Pesticide-Induced Diseases: Sexual and Reproductive Dysfunction
A robust body of literature details reproductive effects in fish, amphibians, and reptiles related to exposure to endocrine disruptors. Evidence of these effects has also been seen in wild mammals such as polar bears and seals. Environmental exposure assessments and wildlife, laboratory and epidemiologic studies show exposure to low-level environmental contaminants, such as pesticides and other chemicals, subtly undermines the ability to reproduce. The study of endocrine disruption is revealing mechanisms that show how specific environmental contaminants can alter fertility. Laboratory animal experiments have confirmed these wildlife findings.
- Impact of Chronic Multi-Generational Exposure to an Environmentally Relevant Atrazine Concentration on Testicular Development and Function in Mice
A common herbicide, atrazine, is associated with poor health. Atrazine acts as an endocrine disruptor at supra-environmental levels. Little research, however, has been conducted regarding chronic exposure to environmental atrazine concentrations across generations. This study utilized comprehensive endpoint measures to investigate the effects of chronic exposure to a conservative atrazine concentration (0.02 ng/mL), measured in Australian waterways, on male mice fertility across two generations. Mice were exposed through the maternal line, from the pre-conception period and through the F1 and F2 generations until three or six months of age. Atrazine did not impact sperm function, testicular morphology nor germ cell parameters but did alter the expression of steroidogenic genes in the F1, down-regulating the expression of Cyp17a1 (Cytochrome P450 family 17, subfamily A member 1; p = 0.0008) and Ddx4 (DEAD-box helicase 4; p = 0.007), and up-regulating the expression of Star (Steroidogenic acute regulatory protein; p = 0.017). In the F2, atrazine induced up-regulation in the expression of Star (p = 0.016). The current study demonstrates that chronic exposure to an environmentally relevant atrazine concentration perturbs testicular steroid-associated gene expression that varies across generations. Future studies through the paternal and combined parental lineages should be undertaken to further elucidate the multigenerational effects of atrazine on male fertility.
[Kolaitis, N.D., Finger, B.J., Merriner, D.J., Nguyen, J., Houston, B.J., O’Bryan, M.K., Stringer, J.M., Zerafa, N., Nguyen, N., Hutt, K.J. and Tarulli, G.A., 2023. Cells, 12(4), p.648.]
- Investigating the prevalence of erectile dysfunction among men exposed to organophosphate insecticides.
Erectile dysfunction (ED) poses a significant disease morbidity and contributor to male infertility, where an estimated 20-40% of men are affected annually. While several risk factors have been identified in the etiology of ED (e.g., aging, heart disease, diabetes, and obesity), the complete pathogenesis remains to be elucidated. Over the last few decades, the contribution of environmental exposures to the pathogenesis of ED has gained some attention, though population studies are limited and results are mixed. Among environmental contaminants, organophosphate (OP) insecticides represent one of the largest chemical classes, and chlorpyrifos is the most commonly used OP in the U.S. OP exposure has been implicated in driving biological processes, including inflammation, reactive oxygen species production, and endocrine and metabolism disruption, which have been demonstrated to adversely affect the hypothalamus and testes and may contribute to ED. Currently, studies evaluating the association between OPs and ED within the U.S. general population are sparse. Data were leveraged from the National Health and Nutrition Examination Survey (NHANES), which is an annually conducted, population-based cross-sectional study. Urinary levels of 3,5,6-trichloro-2-pyridinol (TCPy), a specific metabolite of the most pervasive OP insecticide chlorpyrifos, were quantified as measures of OP exposure. ED was defined by responses to questionnaire data, where individuals who replied "sometimes able" or "never able" to achieve an erection were classified as ED. Chi-square, analysis of variance (ANOVA), and multivariable, weighted linear and logistic regression analyses were used to compare sociodemographic variables between quartiles of TCPy exposure, identify risk factors for TCPy exposure and ED, and to analyze the relationship between TCPy and ED. A total of 671 adult men were included in final analyses, representing 28,949,379 adults after survey weighting. Approximately 37% of our cohort had ED. Smoking, diabetes, aging, Mexican-American self-identification, and physical inactivity were associated with higher ED prevalence. Analysis of TCPy modeled as a continuous variable revealed nonsignificant associations with ED (OR = 1.02 95% CI [0.95, 1.09]). Stratification of total TCPy into quartiles revealed increased odds of ED among adults in the second and fourth quartiles, using the first quartile as the reference (OR = 2.04 95% CI [1.11, 3.72], OR = 1.51 95% CI [0.58, 3.93], OR = 2.62 95% CI [1.18, 5.79], for quartiles 2, 3, and 4, respectively). The results of our study suggest a potential role for chlorpyrifos and other OPs the pathogenesis of ED. Future studies are warranted to validate these findings, determine clinical significance, and to investigate potential mechanisms underlying these associations.
[Glover, F., Mehta, A., Richardson, M., Muncey, W., Del Giudice, F., Belladelli, F., Seranio, N. and Eisenberg, M.L., 2023. Journal of Endocrinological Investigation, pp.1-11.]
- Pesticides exposure in pregnant Argentinian women: Potential relations with the residence areas and the anthropometric neonate parameters.
Intrauterine environment is the first chemical exposure scenario in life, through transplacental transfer. In this study, the aim was to determine concentrations of organochlorine pesticides (OCPs) and selected current use pesticides in the placentas of pregnant women from Argentina. Socio-demographic information, the mother's lifestyle and neonatal characteristics were also analysed and related to pesticides residue concentrations. Thus, 85 placentas were collected at birth, from an area of intensive fruit production for the international market, in Patagonia Argentina. Concentrations of 23 pesticides including, trifluralin (herbicide), the fungicides chlorothalonil and HCB, and the insecticides chlorpyrifos, HCHs, endosulfans, DDTs, chlordanes, heptachlors, drins and metoxichlor, were determined by GC-ECD and GC-MS. Results were first analysed all together and then grouped by their residential settings, in urban and rural groups. Total mean pesticide concentration was 582.6 ± 1034.4 ng/g lw, where DDTs (325.9 ± 950.3 ng/g lw) and chlorpyrifos (188.4 ± 365.4 ng/g lw) showed a high contribution. Pesticide levels found exceeded those reported in low, middle and high income countries from Europe, Asia and Africa. In general, pesticides concentrations were not associated with neonatal anthropometric parameters. When the results were analysed by residence place, significantly higher concentrations of total pesticides and chlorpyrifos (Mann Whitney test p = 0.0003 and p = 0.032, respectively) were observed in placentas collected from mothers living in rural settings compared to urban areas. Rural pregnant women presented the highest pesticide burden (5.9 μg), where DDTs and chlorpyrifos were the major constituents. These results suggested that all pregnant women are highly exposed to complex pesticide mixtures, including banned OCPs and the widely used chlorpyrifos. Based on the pesticide concentrations found, our results warn of possible health impacts from prenatal exposure through transplacental transfer. This is one of the first reports of both chlorpyrifos and chlorothalonil concentrations in placental tissue, and contributes to the knowledge of current pesticide exposure in Argentina.
[Rodriguez, P.M., Ondarza, P.M., Miglioranza, K.S., Ramirez, C.L., Vera, B., Muntaner, C. and Guiñazú, N.L., 2023. Chemosphere, 332, p.138790.]
- Associations between persistent organic pollutants and endometriosis: A multiblock approach integrating metabolic and cytokine profiling
Humans are exposed daily to complex mixtures of chemical pollutants through their environment and diet, some of which have the potential to disrupt the bodies’ natural endocrine functions and contribute to reproductive diseases like endometriosis. Increasing epidemiological and experimental evidence supports the association between endometriosis and certain persistent organic pollutants (POPs) like dioxins; however, little is known about the underlying linking mechanisms. The main objective of this study is to proof the methodological applicability and discovery potential of integrating ultra-trace mass spectrometry (MS) profiling of POP biomarkers and endogenous biomarker profiling (MS metabolomics and cytokines) in a case-control study for the etiological research of endometriosis. The approach is applied in a pilot clinical-based study conducted in France where women with and without surgically confirmed endometriosis were recruited. Serum samples were analysed with high-resolution MS for about 30 polychlorinated biphenyls (PCBs), organochlorinated pesticides and perfluoroalkyl substances (PFAS). About 600 serum metabolites and lipids were identified with targeted metabolomics using tandem MS with the Biocrates MxP® Quant 500 Kit. A panel of 4 pro-inflammatory cytokines were analysed using ELISA-based 4-PLEX analyser. Statistical analysis included a battery of variable selection approaches, multivariate logistic regression for single-chemical associations, Bayesian kernel machine regressions (BKMR) to identify mixture effects of POPs and a multiblock approach to identify shared biomarker signatures among high risk clusters. The results showed the positive associations between some POPs and endometriosis risk, including the pesticide trans-nonachlor Odds Ratio (95% Confidence Interval) 3.38 (2.06–5.98), p < 0.0001 and PCB 114 OR (95% CI) 1.83 (1.17–2.93), p = 0.009. The BKMR approach showed a tendency of a positive cumulative effect of the mixture, however trans-nonachlor exhibited significant associations within the mixture and interacted with other PCBs, strengthening the effects at highest concentrations. Finally, the multiblock analysis, relating the various blocks of data, revealed a latent cluster of women with higher risk of endometrioma presenting higher concentrations of trans-nonachlor, PCB 114 and dioxin-like toxic equivalents from PCBs, together with an increased inflammatory profile (i.e. elevated interleukin-8 and monocyte chemoattractant protein-1). It was also highlighted a specific metabolic pattern characterized by dysregulation of bile acid homeostasis and lipase activity. Further research will be required with larger sample size to confirm these findings and gain insight on the underlying mechanisms between POPs and endometriosis.
[Matta, K., Lefebvre, T., Vigneau, E., Cariou, V., Marchand, P., Guitton, Y., Royer, A.L., Ploteau, S., Le Bizec, B., Antignac, J.P. and Cano-Sancho, G. Environment International, 158, p.106926.]
- Effects of the endocrine disruptor vinclozolin in male reproduction: a systematic review and meta-analysis
Endocrine disrupting chemicals (EDCs) have become an issue of scientific and public discussion. Vinclozolin (VNZ) is a fungicide that competitively antagonizes the binding of natural androgens to their receptor, disturbing the function of tissues that are sensitive to these hormones, as is the case of the male reproductive organs. A systematic review with meta-analyses of rodent studies was conducted to answer the following question: does exposure to VNZ affect sperm parameters and testicular/epididymal weight? The methodology was prespecified according to the Cochrane Handbook for Systematic Reviews and PRISMA recommendations. Sixteen articles met the inclusion criteria, comprising a total of 1189 animals. The risk of publication bias was assessed using the Trim and Fill adjustment, funnel plot and Egger's regression test. Heterogeneity and inconsistency across the findings were tested using the Q-statistic and I2 of Higgins, respectively. Sensitivity was also analysed. Statistical analysis was performed on Comprehensive Meta-Analysis software (Version 2.0), using random models and weighted mean differences along with a 95% confidence interval. Sperm motility, counts, daily sperm production (DSP, evidence of publication bias) and epididymis weight were decreased in VNZ-treated animals. Exposure length and dose, as well as the time point of exposure, influenced the obtained results. Despite the moderate/high heterogeneity observed, the sensitivity analysis overall demonstrated the robustness of the findings. The quality scores of the included studies were superior to 4 in a total of 9, then classified as good. The obtained data corroborate the capability of VNZ exposure to disrupt spermatogenic output and compromise male fertility.
[Feijó, M., Martins, R.V., Socorro, S., Pereira, L. and Correia, S., 2021. Biology of Reproduction.]
- Persistent organic pollutants and the size of ovarian reserve in reproductive-aged women
Industrial chemicals such as persistent organic pollutants (POPs) have been associated with reduced fertility in women, including longer time-to-pregnancy (TTP), higher odds for infertility, and earlier reproductive senescence. Fertility is highly dependent on the ovarian reserve, which is composed of a prenatally determined stock of non-growing follicles. The quantity and quality of the follicles decline with age, thereby eventually leading to menopause. In the clinical setting, assessing ovarian reserve directly through the histological analysis of follicular density in ovaries is not practical. Therefore, surrogate markers of ovarian reserve, such as serum anti-Müllerian hormone (AMH) are typically used. Here, we studied associations between chemical exposure and ovarian reserve in a cohort of pregnant women undergoing elective caesarean section (n = 145) in Stockholm, Sweden. Full data (histological, clinical, serum) were available for 50 women. We estimated the size of the reserve both directly by determining the density of follicles in ovarian cortical tissue samples, and indirectly by measuring AMH in associated serum samples. Concentrations of 9 organochlorine pesticides (OCPs), 10 polychlorinated biphenyls (PCBs), 3 polybrominated diphenylethers (PBDEs) and 9 perfluoroalkyl substances (PFAS) were determined in serum, and clinical data were retrieved from electronic medical records. Healthy follicle densities (median 0, range 0–193 follicles/mm3) and AMH levels (median 2.33 ng/mL, range 0.1–14.8 ng/mL) varied substantially. AMH correlated with the density of growing follicles. Twenty-three chemicals detected in more than half of the samples were included in the analyses. None of the chemicals, alone or as a mixture, correlated with AMH, growing or atretic follicles. However, HCB, transnonachlor, PCBs 74 and 99 were associated with decreased non-growing follicle densities. HCB and transnonachlor were also negatively associated with healthy follicle density. Further, mixture of lipophilic POPs (PBDE 99, p,p’-DDE, and PCB 187) was associated with lower non-growing follicle densities. In addition, exposure to HCB, p,p’-DDE, and mixture of OCPs were significantly associated with higher odds of infertility. The results suggest that exposure to chemicals may reduce the size of ovarian reserve in humans, and strongly encourage to study mechanisms behind POP-associated infertility in women in more detail.
[Björvang, R.D., Hassan, J., Stefopoulou, M., Gemzell-Danielsson, K., Pedrelli, M., Kiviranta, H., Rantakokko, P., Ruokojärvi, P., Lindh, C.H., Acharya, G. and Damdimopoulou, P. Environment International, 155, p.106589.]
- Association of urinary metabolites of organophosphate and pyrethroid insecticides, and phenoxy herbicides with endometriosis
Endometriosis is a hormone-responsive gynecologic disease, signifying its connotations across a woman’s life span. Previous studies suggested that endocrine disrupting chemicals were risk factors for endometriosis. Nevertheless, little is known on exposure to organophosphate, pyrethroid and phenoxy acid pesticides on endometriosis diagnosis. In this study, we determined the concentrations of 11 pesticides, metabolites of organophosphate and pyrethroid insecticides, and phenoxy herbicides, in urine collected from 619 reproductive-age women in Utah and California, using liquid chromatography-tandem mass spectrometry. The association of urinary concentrations of pesticides with an increase in the odds of endometriosis diagnosis was examined in 594 women who underwent laparoscopy/laparotomy (operative cohort: n = 471) or pelvic magnetic resonance imaging (population cohort: n = 123), during 2007–2009. 2-Isopropyl-4-methyl-6-hydroxypyrimidine (IMPY), malathion dicarboxylic acid (MDA), para-nitrophenol (PNP), 3,5,6-trichloro-2-pyridinol (TCPY), 3-phenoxybenzoic acid (3-PBA), and 2,4-dichlorophenoxyacetic acid (2,4-D) were detected in ≥95% of the urine samples analyzed. Urinary concentrations of IMPY, MDA, PNP, 3-PBA and 2,4-D tended to be higher in younger, non-Hispanic black, nulliparous and less affluent women. IMPY was the most dominant compound in urine followed by PNP and TCPY. When women in the 4th quartile of IMPY and the 2nd quartile of TCPY concentrations (μg/g creatinine) were compared with women in the 1st quartile, the odds ratios (ORs) for diagnosis of endometriosis increased significantly in unadjusted models (IMPY OR = 1.89, 95% confidence interval (Cl) = 1.12–3.20; TCPY OR = 1.65, 95% Cl = 1.02–2.69) for the operative (n = 471) and entire data set (n = 594), respectively. Our results suggest that exposure to elevated concentrations of diazinon (the parent compound of IMPY) and chlorpyrifos and chlorpyrifos-methyl (parent compounds of TCPY) may be associated with endometriosis.
[Li, A.J., Chen, Z., Lin, T.C., Louis, G.M.B. and Kannan, K., 2020. Environment International, 136, p.105456.]
- Effects of environmental pyrethroids exposure on semen quality in reproductive-age men in Shanghai, China
Animal experiments have revealed that pyrethroids (PYRs) exposure could affect semen quality, however evidence on humans being is limited and controversial.To explore the potential effects of environmental PYRs exposure on semen quality in reproductive age men. We conducted a cross-sectional study of 346 men who planned to conceive and addressed to hospital for preconception examination. PYRs exposure was assessed by analyzing PYRs urinary metabolites [3-phenoxybenzoic acid (3PBA), trans- and cis-3-(2,2-Dichlorovinyl) −2,2-dimethylcy clopropane carboxylic acid (TDCCA and CDCCA)] levels using gas chromatography-mass spectrometry. Semen quality was assessed by a computer-aided semen analyzer.For a detection rate of 99.7%, 76.6%, and 22.0%, the median levels (μg/g creatinine) of PYRs metabolites were 0.46 for 3PBA, 0.38 for TDCCA and under detection limit for CDCCA. Linear regression models found negative associations between 3PBA and sperm morphology (β = −2.12, 95% CI: −4.02 to −0.22) as well as between TDCCA and log-transformed total sperm count (β = −0.09, 95% CI: −0.16 to −0.01). In logistic regression models, men with the highest quartile of 3PBA had higher risk of poor semen quality (having below-reference semen parameter, OR = 2.40, 95% CI: 1.26 to 4.54; having below-reference sperms morphology, OR = 3.08, 95% CI: 1.10 to 8.60) compared to men in the lowest quartile. Our study suggests that environmental PYRs exposure might adversely affect semen parameters of reproductive age men in Shanghai, China. Further studies are needed to confirm our findings and demonstrate a causal relationship between PYRs exposure and semen quality.
[Hu, Y., Zhang, Y., Vinturache, A., Wang, Y., Shi, R., Chen, L., Qin, K., Tian, Y. and Gao, Y., 2020. Chemosphere, 245, p.125580.]
- Long-term maternal exposure to atrazine in the drinking water reduces penis length in the tammar wallaby Macropus eugenii
Marsupials are experiencing devastating population declines across Australia. Exposure to environmental endocrine disruptors, through ingestion of contaminated resources in the environment, could be contributing to this decline. Atrazine (ATZ), a widely used herbicide in Australia, is an endocrine disruptor with the ability to cause reproductive abnormalities in a diverse range of vertebrates. We exposed adult female wallabies (Macropus eugenii) to drinking water containing ATZ (450 p.p.m) throughout pregnancy, parturition and lactation. We assessed the outcome of this exposure to the reproductive development of their young by assessing gonad and phallus development. Both these organs are especially sensitive to perturbations in the hormonal environment during development. Although no gross abnormalities were seen in gonad structure, exposure to ATZ did alter the expression of genes required for normal testis function. Furthermore, long-term exposure to ATZ resulted in a significant reduction in penis length. These results demonstrate that ATZ exposure during gestation and lactation can significantly affect the development of male young by affecting virilisation. Given the known vulnerability of macropodid marsupials to endocrine disruption, as well as their overlapping distribution with agricultural areas, these data raise major concerns for the use of pesticides in areas with fragile marsupial populations.
[Cook, L.E., Chen, Y., Renfree, M.B. and Pask, A.J., 2020. Reproduction, Fertility and Development, 32(13), pp.1168-1168.]
- Prenatal exposure to pesticides and risk for holoprosencephaly: a case-control study
Pesticide exposure during susceptible windows and at certain doses are linked to numerous birth defects. Early experimental evidence suggests an association between active ingredients in pesticides and holoprosencephaly (HPE), the most common malformation of the forebrain in humans (1 in 250 embryos). No human studies to date have examined the association. This study investigated pesticides during multiple windows of exposure and fetal risk for HPE. It is hypothesized that pre-conception and early pregnancy, the time of brain development in utero, are the most critical windows of exposure. A questionnaire was developed for this retrospective case-control study to estimate household, occupational, and environmental pesticide exposures. Four windows of exposure were considered: preconception, early, mid and late pregnancy. Cases were identified through the National Human Genome Research Institute’s ongoing clinical studies of HPE. Similarly, controls were identified as children with Williams-Beuren syndrome, a genetic syndrome also characterized by congenital malformations, but etiologically unrelated to HPE. We assessed for differences in odds of exposures to pesticides between cases and controls. Findings from 91 cases and 56 controls showed an increased risk for HPE with reports of maternal exposure during pregnancy to select pesticides including personal insect repellants (adjusted odds ratio (aOR) 2.89, confidence interval (CI): 0.96–9.50) and insecticides and acaricides for pets (aOR 3.84, CI:1.04–16.32). Exposure to household pest control products during the preconception period or during pregnancy was associated with increased risk for HPE (aOR 2.60, OR: 0.84–8.68). No associations were found for occupational exposures to pesticides during pregnancy (aOR: 1.15, CI: 0.11–11.42), although exposure rates were low. Higher likelihood for HPE was also observed with residency next to an agricultural field (aOR 3.24, CI: 0.94–12.31). Observational findings are consistent with experimental evidence and suggest that exposure to personal, household, and agricultural pesticides during pregnancy may increase risk for HPE. Further investigations of gene by environment interactions are warranted.
[Addissie, Y.A., Kruszka, P., Troia, A., Wong, Z.C., Everson, J.L., Kozel, B.A., Lipinski, R.J., Malecki, K.M. and Muenke, M., 2020. Environmental Health, 19(1), pp.1-13.]
- Assessment of Glyphosate Induced Epigenetic Transgenerational Inheritance of Pathologies and Sperm Epimutations: Generational Toxicology
Ancestral environmental exposures to a variety of factors and toxicants have been shown to promote the epigenetic transgenerational inheritance of adult onset disease. One of the most widely used agricultural pesticides worldwide is the herbicide glyphosate (N-(phosphonomethyl)glycine), commonly known as Roundup. There are an increasing number of conflicting reports regarding the direct exposure toxicity (risk) of glyphosate, but no rigorous investigations on the generational actions. The current study using a transient exposure of gestating F0 generation female rats found negligible impacts of glyphosate on the directly exposed F0 generation, or F1 generation offspring pathology. In contrast, dramatic increases in pathologies in the F2 generation grand-offspring, and F3 transgenerational great-grand-offspring were observed. The transgenerational pathologies observed include prostate disease, obesity, kidney disease, ovarian disease, and parturition (birth) abnormalities. Epigenetic analysis of the F1, F2 and F3 generation sperm identified differential DNA methylation regions (DMRs). A number of DMR associated genes were identified and previously shown to be involved in pathologies. Therefore, we propose glyphosate can induce the transgenerational inheritance of disease and germline (e.g. sperm) epimutations. Observations suggest the generational toxicology of glyphosate needs to be considered in the disease etiology of future generations.
[Kubsad, D., Nilsson, E.E., King, S.E., Sadler-Riggleman, I., Beck, D. and Skinner, M.K., 2019. Scientific reports, 9(1), pp.1-17.]
- Association of Maternal Insecticide Levels With Autism in Offspring From a National Birth Cohort
Autism is a complex neurodevelopmental disorder with a largely unknown etiology. To date, few studies have investigated prenatal exposure to toxins and risk of autism by using maternal biomarkers of exposure. Persistent organic pollutants are lipophilic halogenated organic compounds and include the insecticide dichlorodiphenyltrichloroethane (DDT), as well as its metabolite p,p′-dichlorodiphenyl dichloroethylene (p,p′-DDE), and polychlorinated biphenyls (PCBs). The objective of this study was to test whether elevated maternal levels of persistent organic pollutants are associated with autism among offspring. The investigation was derived from the Finnish Prenatal Study of Autism, a national birth cohort study based on a nested case-control design. Cases of autism among children born between 1987 and 2005 were ascertained by national registry linkages. In cases of childhood autism and matched control subjects (778 matched case-control pairs), maternal serum specimens from early pregnancy were assayed for levels of p,p′-DDE and total levels of PCBs. The odds of autism among offspring were significantly increased with maternal p,p′-DDE levels that were in the highest 75th percentile, with adjustment for maternal age, parity, and history of psychiatric disorders (odds ratio=1.32, 95% CI=1.02, 1.71). The odds of autism with intellectual disability were increased by greater than twofold with maternal p,p′-DDE levels above this threshold (odds ratio=2.21, 95% CI=1.32, 3.69). There was no association between total levels of maternal PCBs and autism. These findings provide the first biomarker-based evidence that maternal exposure to insecticides is associated with autism among offspring. Although further research is necessary to replicate this finding, this study has implications for the prevention of autism and may provide a better understanding of its pathogenesis.
[Brown, A.S., Cheslack-Postava, K., Rantakokko, P., Kiviranta, H., Hinkka-Yli-Salomäki, S., McKeague, I.W., Surcel, H.M. and Sourander, A., 2018. American Journal of Psychiatry, 175(11), pp.1094-1101.]
- Mixed "Antiandrogenic" Chemicals at Low Individual Doses Produce Reproductive Tract Malformations in the Male Rat.
Biomonitoring efforts have clearly shown that all humans are exposed to chemical mixtures. Of concern is whether or not exposure to mixtures during pregnancy contributes to congenital abnormalities in children even when each chemical is at an individual dose that does not affect the fetus. Here, we hypothesized that in utero exposure to a mixture of chemicals covering multiple "antiandrogenic" mechanisms of action at doses that individually have no adverse effect would result in permanent reproductive tract alterations in the male rat after birth. Pregnant dams were exposed to a range of dilutions (100%, 50%, 25%, 12.5%, 6.25%, or vehicle control) of a mixture containing pesticides, phthalates, and drugs (p, p'-DDE, linuron, prochloraz, procymidone, pyrifluquinazon, vinclozolin, finasteride, flutamide, simvastatin, and 9 phthalates [dipentyl, dicyclohexyl, di-2-ethylhexyl, dibutyl, benzyl butyl, diisobutyl, diisoheptyl, dihexyl, and diheptyl]). The top dose contained each chemical at 20% of its lowest observed adverse effect level (LOAEL) for the most sensitive male reproductive alteration following in utero exposure. We found that male rat offspring displayed a variety of neonatal, pubertal, and permanent adult effects across all dose levels. Even at the lowest dose (each chemical approximately 80-fold below lowest observed adverse effect level) there were permanent reductions in several reproductive tract tissue weights. In the top dose group, 100% of male offspring displayed permanent severe birth defects including genital malformations. Despite acting via 5 different molecular initiating events, a mixture of 18 chemicals can combine to produce additive effects even when each compound is at a relatively low dose.
[Conley JM, Lambright CS, Evans N, Cardon M, et al. Toxicol Sci. 164(1):166-178]
- Organophosphate and Pyrethroid Pesticide Exposures Measured before Conception and Associations with Time to Pregnancy in Chinese Couples Enrolled in the Shanghai Birth Cohort.
Pesticides have been associated with reproductive disorders, but there is limited research on pesticide exposures and human fertility. We aimed to investigate the effects of preconception exposure to pesticides on time to pregnancy (TTP) and on infertility in a general population of couples planning to become pregnant in Shanghai, China. A total of 615 women who were planning a pregnancy were enrolled before conception and were prospectively followed for 1 y to observe their TTP. Preconception pesticide exposures were assessed by measuring urinary metabolites of organophosphates (OPs) and pyrethroids (PYRs). Fecundability odds ratios (FORs) and odds ratios (ORs) of infertility were estimated using Cox and logistic regression models, respectively. All analyses were repeated after restricting the sample to nulliparous women (n=569). After adjusting for age, prepregnancy BMI, current smoking, education, annual household income, age at menarche, and two items from the Perceived Stress Scale (PSS-10), women in the highest quartile of diethylthiophosphate (DETP; an OP metabolite) had significantly longer TTP [adjusted FOR=0.68 (95% CI: 0.51, 0.92)] and increased infertility [adjusted OR=2.17 (95% CI: 1.19, 3.93)] compared with women in the lowest quartile. The highest versus lowest quartile of 3-phenoxybenzoic acid (3PBA; a PYR metabolite) was associated with longer TTP and infertility, with significant associations in nulliparous women [adjusted FOR=0.72 (95% CI: 0.53, 0.98); adjusted OR for infertility=2.03 (95% CI: 1.10, 3.74)].Our study provides some of the first evidence that preconception OP and PYR exposures are associated with decreased fertility in Chinese couples. Given that OPs and PYRs are rapidly metabolized in humans, more studies are needed to confirm our findings.
[Hu Y, Ji L, Zhang Y, Shi R, Han W, Tse LA, et al. 2018. Environ Health Perspect. 126(7):077001]
- Prenatal Exposure to Ambient Pesticides and Preterm Birth and Term Low Birthweight in Agricultural Regions of California.
Findings from studies of prenatal exposure to pesticides and adverse birth outcomes have been equivocal so far. We examined prenatal exposure to agricultural pesticides in relation to preterm birth and term low birthweight, respectively, in children born between 1998 and 2010, randomly selected from California birth records. We estimated residential exposure to agriculturally applied pesticides within 2 km of residential addresses at birth by pregnancy trimester for 17 individual pesticides and three chemical classes (organophosphates, pyrethroids, and carbamates). Among maternal addresses located within 2 km of any agricultural pesticide application, we identified 24,693 preterm and 220,297 term births, and 4412 term low birthweight and 194,732 term normal birthweight infants. First or second trimester exposure to individual pesticides (e.g., glyphosates, paraquat, imidacloprid) or exposure to 2 or more pesticides in the three chemical classes were associated with a small increase (3⁻7%) in risk for preterm birth; associations were stronger for female offspring. We did not find associations between term low birthweight and exposure to pesticides other than myclobutanil (OR: 1.11; 95% CI: 1.04⁻1.20) and possibly the pyrethroids class. Our improved exposure assessment revealed that first and second trimester exposure to pesticides is associated with preterm delivery but is rarely linked with term low birthweight.
[Ling C, Liew Z, von Ehrenstein OS, Heck JE, et al. 2018. Toxics. 6(3). pii: E41]
- Allethrin toxicity causes reproductive dysfunction in male rats
Pyrethroids are widely used for domestic and agricultural purposes and their use is increasing, especially in developing countries. Uncontrolled use of these insecticides resulted in their entry into the food chain thereby causing toxicity to different organ systems. Allethrin is one of the widely used pyrethroids, but its toxicological effects are underreported when compared to other pyrethroids. Further, its effects on the male reproductive tract remain uncharacterized. In this study, its toxicity on the male reproductive tract was evaluated by administering 25-150 mg/kg body weight allethrin to adult rats for 60 days. The mRNA expression of factors that are important in spermatogenesis (Scf, c-Kit, Hsf2, Ovol1, Brdt, Kdm3A, Ybx-2, and Grth) and steroidogenesis (StAR, 3β-HSD, 17β-HSD) was significantly downregulated. Decreased levels of testosterone, reduced sperm count and daily sperm production was also observed due to allethrin toxicity. However, sperm quality parameters assessed by computer-assisted sperm analyzer were not affected. Spermatozoa obtained from allethrin-treated rats failed to undergo acrosome reaction. Results of this study indicate that allethrin affects spermatogenesis and sperm function, thus lending further support to the growing evidence of its toxicity.
[Madhubabu G, Yenugu S. 2017. Environ Toxicol. 32(6):1701-1710. ]
- Association of reproductive disorders and male congenital anomalies with environmental exposure to endocrine active pesticides.
There is growing evidence that environmental exposure to pesticides may increase the risk of developing reproductive and developmental disorders. This study determined the prevalence and risk of developing gestational disorders and male congenital genitourinary malformations in areas with distinct exposure to pesticides, many of them with potential endocrine disrupting properties. A population-based case-control study was carried out on pregnant women and male children living in ten health districts of Andalusia classified as areas of high and low environmental exposure to pesticides according to agronomic criteria. The study population included 45,050 cases and 950,620 controls matched for age and health district. Data were collected from computerized hospital records between 1998 and 2005. Prevalence rates and risk of miscarriage, low birth weight, hypospadias, cryptorchidism and micropenis were significantly greater in areas with higher use of pesticides in relation to those with lower use, thus supporting and extending previous information.
[García J, Ventura MI, Requena M, Hernández AF, et al. 2017. Reprod Toxicol. 71:95-100.]
- Association of serum organochlorine pesticides concentrations with reproductive hormone levels and polycystic ovary syndrome in a Chinese population.
To investigate the serum concentrations of organochlorine pesticides (OCPs) in patients with polycystic ovary syndrome (PCOS), a total of 178 women were studied. The concentrations of hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT) in serum were determined using Gas Chromatography Mass-Mass Spectrometer. No differences with statistical significance in the mean HCH, p,p'-DDD, p,p'-DDE concentrations were observed between the patients with PCOS and the control group. Serum p,p'-DDT (P = 0.016) and o,p'-DDT (P = 0.000) levels were significantly higher in patients with PCOS compared with the control group. The results of the association between OCPs levels and hormone levels indicated that o,p'-DDT may play a role in the pathogenesis of PCOS by affecting hormones levels. Further trials should be investigated with the findings in this study to obtain new pathogenesis of PCOS.
[Guo Z, Qiu H, Wang L, Wang L, et al. 2017. Chemosphere. 171:595-600.]
- Chronic exposure to the fungicide propiconazole: Behavioral and reproductive evaluation of F1 and F2 generations of male rats.
Several studies have suggested that propiconazole (PROP) may be an endocrine disruptor; possibly altering the activity of the CYP51 enzyme, which is part of the cholesterol biosynthesis pathway required for the production of sexual steroid hormones. Another PROP effect is inhibition of the aromatase enzyme that converts androgens into estrogens, which could lead to negative effects on reproductive parameters. Therefore, the present study evaluated the reproductive and developmental toxicity of PROP by exposing two generations (F1 and F2) of male rats to this fungicide, since a previous study from our lab reported that PROP has anti-estrogenic and anti-androgenic activities (Costa et al., 2015) in the male parental (P) generation. The F1 males were exposed to PROP (4 or 20mg/kg) through germ cells (via the P generation), intra uterus, and lactation, following treatment by gavage from post-natal day (PND) 21 to 120, while the F2 generation was exposed through germ cells, intra uterus, and lactation. The parameters observed in both F1 and F2 generations were: body weight, anogenital distance (PND 0 and 21), ontogenic reflex, testosterone plasmatic levels, testis weight, and testicular histomorphology (PND 21); and in the F1 generation only: preputial separation (PND 40), sexual behavior, organ weights, testosterone and estradiol plasmatic levels (PND 120), sperm count and morphology, and testicular histomorphology at adulthood. In the F1 and F2 generations, PROP (4mg/kg) presented a decrease in testosterone levels, and in the F1 decreases in the vas deferens weight, without hormonal and functional changes of the reproductive organs, either at 4mg/kg or at 20mg/kg, in adulthood. Based on the results of this work, PROP did not alter the gonadal-endocrine parameters under these exposure conditions in rats.
[Vieira ML, Costa NO, Pereira MRF, et al. 2017. Toxicology. 389:85-93.]
- Combined exposure to low doses of pesticides causes decreased birth weights in rats
Decreased birth weight is a common effect of many pesticides in reproductive toxicity studies, but there are no empirical data on how pesticides act in combination on this endpoint. We hypothesized that a mixture of six pesticides (cyromazine, MCPB, pirimicarb, quinoclamine, thiram, and ziram) would decrease birth weight, and that these mixture effects could be predicted by the Dose Addition model. Data for the predictions were obtained from the Draft Assessment Reports of the individual pesticides. A mixture of equi-effective doses of these pesticides was tested in two studies in Wistar rats, showing mixture effects in good agreement with the additivity predictions. Significantly lower birth weights were observed when compounds were present at individual doses below their no-observed adverse effect levels (NOAELs). These results emphasize the need for cumulative risk assessment of pesticides to avoid potentially serious impact of mixed exposure on prenatal development and pregnancy in humans.
[Hass U, Christiansen S, Axelstad M, Scholze M, Boberg J. 2017. Reprod Toxicol. 72:97-105]
- Disruption of aromatase homeostasis as the cause of a multiplicity of ailments: A comprehensive review.
Human health is beset with a legion of ailments, which is exacerbated by lifestyle errors. Out of the numerous enzymes in human body, aromatase, a cytochrome P450 enzyme is particularly very critical. Occurring at the crossroads of multiple signalling pathways, its homeostasis is vital for optimal health. Unfortunately, medications, hormone therapy, chemical additives in food, and endocrine-disrupting personal care products are oscillating the aromatase concentration beyond the permissible level. As this enzyme converts androgens (C19) into estrogens (C18), its agitation has different outcomes in different genders and age groups. Some common pathologies associated with aromatase disruption include breast cancer, prostate cancer, polycystic ovary syndrome (PCOS), endometriosis, osteoporosis, ovarian cancer, gastric cancer, pituitary cancer, Alzheimer's disease, schizophrenia, male hypogonadism, and transgender issues. Several drugs, cosmetics and pesticides act as the activators and suppressors of this enzyme. This carefully-compiled critical review is expected to increase public awareness regarding the threats resultant of the perturbations of this enzyme and to motivate researchers for further investigation of this field.
[Patel S. 2017. J Steroid Biochem Mol Biol.168:19-25]
- Effects of melatonin in rats in the initial third stage of pregnancy exposed to sub-lethal doses of herbicides.
Exposure to the herbicides Paraquat (PQ) and Roundup® may cause cell lesions due to an increase in oxidative stress levels in different biological systems, even in the reproductive system. This study evaluated the possible changes in reproductive parameters and hepatic, as well as its prevention by simultaneous application of melatonin.Thirty-five female rats at the age of 3 months were divided into seven groups: three groups exposed to sub-lethal doses of the herbicides PQ (50mg/kg) and Roundup® (500mg/kg) (n=5, G2, G3 and G4); three groups exposed to herbicides and simultaneous treatment with 10mg/kg of Melatonin (n=5, G5, G6 and G7) and control group (n=5, G1) from the first to the seventh day of pregnancy. On the seventh day of pregnancy, the rats were anesthetized and euthanized, followed by laparotomy to remove their reproductive tissues and liver. Body and ovary weights were taken and the number of implantation sites, corpora lutea, preimplantation losses, implantation rates were counted and histopathology of the implantation sites, morphometry of the surface and glandular epithelia of endometrium and hepatic oxidative stress were undertaken.The present study shows the decrease in body and ovary weight, decrease in the number of implantation sites, implantation rate, in the total number of corpora lutea and increase of preimplantation percentages were observed when compared to the G1. The histopathological analysis of the implantation sites showed a disorder of the cytotrophoblast and cell degeneration within the blastocyst cavity in Fig. 4. Morphometry revealed a reduction in surface and glandular epithelia and in the diameter of the endometrial glands (Table 2; p>0.05 ANOVA/Tukey), whereas in liver, serum levels of thiobarbituric acid reactive substances (TBARS) were found to be significantly elevated (Fig. 2; p>0.001; p>0.05 ANOVA/Tukey), and serum level of reduced glutathione (GSH) was significantly lower (Fig. 3; p>0.001 ANOVA/Tukey). However, treatments with melatonin exhibited improvements in reproductive parameters, as well as reduced lesions in the implantation sites and in serum levels TBARS, serum levels GSH.These results reveal that melatonin is a protective agent against experimentally induced maternal/embryo toxicity with herbicides and favoring normalization of reproductive parameters and hepatic.
[Almeida LL, Teixeira ÁAC, Soares AF, Cunha FMD, et al. Acta Histochem. 119(3):220-227.]
- Effects of Neonicotinoid Pesticide Exposure on Human Health: A Systematic Review.
Numerous studies have identified detectable levels of neonicotinoids (neonics) in the environment, adverse effects of neonics in many species, including mammals, and pathways through which human exposure to neonics could occur, yet little is known about the human health effects of neonic exposure.In this systematic review, we sought to identify human population studies on the health effects of neonics. Eight studies investigating the human health effects of exposure to neonics were identified. Four examined acute exposure: Three neonic poisoning studies reported two fatalities (n = 1,280 cases) and an occupational exposure study of 19 forestry workers reported no adverse effects. Four general population studies reported associations between chronic neonic exposure and adverse developmental or neurological outcomes, including tetralogy of Fallot (AOR 2.4, 95% CI: 1.1, 5.4), anencephaly (AOR 2.9, 95% CI: 1.0, 8.2), autism spectrum disorder [AOR 1.3, 95% credible interval (CrI): 0.78, 2.2], and a symptom cluster including memory loss and finger tremor (OR 14, 95% CI: 3.5, 57). Reported odds ratios were based on exposed compared to unexposed groups.The studies conducted to date were limited in number with suggestive but methodologically weak findings related to chronic exposure. Given the wide-scale use of neonics, more studies are needed to fully understand their effects on human health.
[Cimino AM, Boyles AL, Thayer KA, Perry MJ. 2017. Environ Health Perspect. 125(2):155-162]
- Environmental levels of triclosan and male fertility.
Men with higher urinary concentrations of triclosan were found to have poorer semen quality, exhibiting a greater percentage of sperm with abnormal morphology as compared to men with lower triclosan levels. Triclosan is a synthetic chemical with broad antimicrobial activity that has been used extensively in consumer products, including personal care products, textiles, and plastic kitchenware, although the exposure which is widespread evidence from human studies is scarce. Our study aims to investigate the relationship between triclosan exposure and male fertility. Triclosan (TCS) urinary concentrations were measured using gas chromatography coupled with tandem mass spectrometry in 315 men recruited from a male reproductive health clinic with normal sperm concentration (≥ 15 mln/ml) (WHO 2010) under 45 years of age. Participants were interviewed and provided a semen sample. TCS was detected in 84.13% of urine samples, with a median concentration of 2.83 μg/l (2.57 μg/g creatinine). A multiple linear regression analysis showed a positive association between the urinary concentrations of triclosan 50th–75th percentile and ≥ 50 percentile and percentage of sperm with abnormal morphology (p = 0.016 and p = 0.002, respectively). The study provides evidence that exposure to triclosan is associated with poorer semen quality. Future studies are needed to confirm these findings.
[Jurewicz, J et al. 2017. Environmental Science and Pollution Research 25(6), 5484-5490. ]
- Environmental pollutants, a possible etiology for premature ovarian insufficiency: a narrative review of animal and human data.
Because only 25% of cases of premature ovarian insufficiency (POI) have a known etiology, the aim of this review was to summarize the associations and mechanisms of the impact of the environment on this pathology. Eligible studies were selected from an electronic literature search from the PUBMED database from January 2000 to February 2016 and associated references in published studies. The literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data have been grouped according to the studied pollutants in order to synthetize their impact on follicular development and follicular atresia and the molecular pathways involved. Ninety-seven studies appeared to be eligible and were included in the present study, even though few directly address POI. Phthalates, bisphenol A, pesticides and tobacco were the most reported substances having a negative impact on ovarian function with an increased follicular depletion leading to an earlier age of menopause onset. These effects were found when exposure occured at different times throughout the lifetime from the prenatal to the adult period, possibly due to different mechanisms. The main mechanism seemed to be an increase in atresia of pre-antral follicles. Environmental pollutants are probably a cause of POI. Health officials and the general public must be aware of this environmental effect in order to implement individual and global preventive actions.
[Vabre P, Gatimel N, Moreau J, Gayrard V, et al. 2017. Environ Health. 16(1):37.]
- Exposure to endocrine disruptors during adulthood: consequences for female fertility.
Endocrine disrupting chemicals are ubiquitous chemicals that exhibit endocrine disrupting properties in both humans and animals. Female reproduction is an important process, which is regulated by hormones and is susceptible to the effects of exposure to endocrine disrupting chemicals. Disruptions in female reproductive functions by endocrine disrupting chemicals may result in subfertility, infertility, improper hormone production, estrous and menstrual cycle abnormalities, anovulation, and early reproductive senescence. This review summarizes the effects of a variety of synthetic endocrine disrupting chemicals during adult life. The chemicals covered in this review are pesticides (organochlorines, organophosphates, carbamates, pyrethroids, and triazines), heavy metals (arsenic, lead, and mercury), diethylstilbesterol, plasticizer alternatives (di-(2-ethylhexyl) phthalate and bisphenol A alternatives), 2,3,7,8-tetrachlorodibenzo-p-dioxin, nonylphenol, polychlorinated biphenyls, triclosan, and parabens. This review focuses on the hypothalamus, pituitary, ovary, and uterus because together they regulate normal female fertility and the onset of reproductive senescence. The literature shows that several endocrine disrupting chemicals have endocrine disrupting abilities in females during adult life, causing fertility abnormalities in both humans and animals.
[Rattan S, Zhou C, Chiang C, Mahalingam S, Brehm E, Flaws J. J Endocrinol. pii: JOE-17-0023. ]
- Exposure to PFOA and PFOS and fetal growth: a critical merging of toxicological and epidemiological data.
Toxicological and epidemiological evidence on the association between perfluorooctanoic acid (PFOA) or perfluorooctane sulfonic acid (PFOS) and birth/fetal weight was assessed. An extensive search for toxicological information in rats and mice, and a systematic search for epidemiological evidence were conducted. The linear regression coefficient (LRC) of birth weight (BrthW) on PFOA/PFOS was considered, and separate random effects meta-analyses for untransformed (i.e. not mathematically transformed) and log-transformed values were performed. Toxicological evidence: PFOA: 12 studies (21 datasets) in mice showed statistically significant lower birth/fetal weights from 5 mg/kg body weight per day. PFOS: most of the 13 studies (19 datasets) showed lower birth/fetal weights following in utero exposure. Epidemiological evidence: Sixteen articles were considered. The pooled LRC for a 1 ng/mL increase in untransformed PFOA (12 studies) in maternal plasma/serum was -12.8 g (95% CI -23.2; 2.4), and -27.1 g (95% CI -50.6; -3.6) for an increase of 1 loge ng/mL PFOA (nine studies). The pooled LRC for untransformed PFOS (eight studies) was -0.92 g (95%CI -3.4; 1.6), and for an increase of 1 loge ng/mL was -46.1(95% CI -80.3; -11.9). No consistent pattern emerged for study location or timing of blood sampling. Epidemiological and toxicological evidence suggests that PFOA and PFOS elicit a decrease in BrthW both in humans and rodents. However, the effective animal extrapolated serum concentrations are 102-103 times higher than those in humans. Thus, there is no quantitative toxicological evidence to support the epidemiological association, thus reducing the biological plausibility of a causal relationship.
[Negri E, Metruccio F, Guercio V, Tosti L, et al. 2017. Crit Rev Toxicol. 47(6):482-508]
- Glyphosate and Paraquat in Maternal and Fetal Serums in Thai Women
This longitudinal study measured the glyphosate and paraquat concentrations found in maternal and umbilical cord serum in 82 pregnant women who gave birth in three provinces of Thailand.Through questionnaires and biological samples collected at childbirth, factors such as personal characteristics, family members occupation, agricultural activities, and herbicide use in agricultural work were evaluated as predictors of glyphosate and paraquat levels in the pregnant women. Statistical analysis used univariate and binary multiple logistic regression, where the outcome was the probability of exposure to paraquat or glyphosate above the limit of detection associated with occupation and household factors.The glyphosate concentrations in the pregnant women's serum at childbirth (median: 17.5, range: 0.2-189.1 ng/mL) were significantly higher (P < .007) than those in the umbilical cord serum (median: 0.2, range: 0.2-94.9 ng/mL). However, the paraquat concentrations in the serum of the pregnant women at childbirth (83% ≤limit of detection [LOD], with maximum of 58.3 ng/mL) were similar to those in the umbilical cord serum (80% <LOD, with maximum of 47.6 ng/mL). Women with glyphosate levels >LOD in serum at childbirth were 11.9 times more likely to report work as an agriculturist (P < .001), 3.7 times more likely to live near agricultural areas (P = .006), and 5.9 times more likely to have a family member who worked in agriculture (P < .001). The only factors affecting paraquat exposures in pregnant women at childbirth were reporting the agricultural activity of digging in farm soil and working in the agricultural fields in the third trimester of pregnancy.These results show that pregnant women who work in agriculture or live in families that work in agriculture have higher exposures to the herbicides glyphosate and paraquat. The potential for long-term health impacts of these prenatal exposures to children should be evaluated, and greater regulation of the sale and use of herbicides should be considered in Thailand.
[Kongtip P, Nankongnab N, Phupancharoensuk R, et al. 2017. J Agromedicine. 22(3):282-289. ]
- Human exposure to endocrine disrupting chemicals: effects on the male and female reproductive systems.
Endocrine disrupting chemicals (EDCs) comprise a group of chemical compounds that have been examined extensively due to the potential harmful effects in the health of human populations. During the past decades, particular focus has been given to the harmful effects of EDCs to the reproductive system. The estimation of human exposure to EDCs can be broadly categorized into occupational and environmental exposure, and has been a major challenge due to the structural diversity of the chemicals that are derived by many different sources at doses below the limit of detection used by conventional methodologies. Animal and in vitro studies have supported the conclusion that endocrine disrupting chemicals affect the hormone dependent pathways responsible for male and female gonadal development, either through direct interaction with hormone receptors or via epigenetic and cell-cycle regulatory modes of action. In human populations, the majority of the studies point towards an association between exposure to EDCs and male and/or female reproduction system disorders, such as infertility, endometriosis, breast cancer, testicular cancer, poor sperm quality and/or function. Despite promising discoveries, a causal relationship between the reproductive disorders and exposure to specific toxicants is yet to be established, due to the complexity of the clinical protocols used, the degree of occupational or environmental exposure, the determination of the variables measured and the sample size of the subjects examined. Future studies should focus on a uniform system of examining human populations with regard to the exposure to specific EDCs and the direct effect on the reproductive system.
[Sifakis S, Androutsopoulos VP, Tsatsakis AM, Spandidos DA. 2017. Environ Toxicol Pharmacol. 51:56-70.]
- Impact of chlorpyrifos on human villous trophoblasts and chorionic villi.
Placental barrier regulates maternal-fetal interchange protecting the baby from damage caused by substances found in the uterine environment or circulating in the vascular system. Organophosphate (OP) pesticides are a paramount group of environmental pollutants used in intensive agriculture for protection against diseases and pests. While many studies have reported an increased risk of pregnancy alterations in pregnant women exposed to OPs, few have analyzed the effects caused by these pesticides in the placenta. Herein, we evaluated the effects of chlorpyrifos (CPF), one of the most widely used OP insecticides, on human placenta using in vitro and ex vivo exposure models. Villous cytotrophoblast cells isolated from normal human term placentas maintained their cell viability, differentiated into syncytiotrophoblast-like structures, and increased the expression of β-hCG, ABCG2, and P-gp in the presence of CPF at concentrations of 10 to 100μM. The same doses of CPF induced marked changes in chorionic villi samples. Indeed, CPF exposure increased stroma cell apoptosis, altered villi matrix composition, basement membrane thickness, and trophoblastic layer integrity. Histomorphological and ultrastructural alterations are compatible with those found in placentas where maternal-placenta injury is chronic and able to impair the placental barrier function and nutrient transport from mother to the fetus. Our study shows that placental ex vivo exposure to CPF produces tissue alterations and suggest that human placenta is a potential target of CPF toxicity. In addition, it highlights the importance of using different models to assess the effects of a toxic on human placenta.
[Ridano ME, Racca AC, Flores-Martin JB, Fretes R, et al. 2017. Toxicol Appl Pharmacol. 329:26-39]
- Impact of oocytes with CLCG on ICSI outcomes and their potential relation to pesticide exposure
Oocyte quality is a key limiting factor in female fertility which is primarily reflected in morphological features. Centrally located cytoplasm granulation (CLCG) is one type of cytoplasmic dimorphism exhibited by oocytes that could be linked to pesticide exposure with a significant risk of decreased ICSI outcomes.This retrospective study included 633 women who were part of an intracytoplasmic spermatozoa injection (ICSI) program between 2009 and 2011. The participants lived in the Picardy region of France and had been exposed to pesticides. The participants were divided in two groups based on prevalence of oocytes with CLCG (LCLCG [n = 83]: low prevalence of oocytes with CLCG under 25%. HCLCG [n = 68]: high prevalence of CLCG over 75%). The embryological and clinical outcomes were analysed for both groups and were calculated using the difference between the two values.Results for couples with HCLCG compared to LCLCG showed a decrease in embryo cleavage, ongoing pregnancy, and live birth rates (82%, 14%, 13% vs 99%, 32%, 30%, respectively).The early miscarriage rate was increased (47% vs 11%), with an OR of 3.1 (95%CI [2.1-4.1]). Due to high pesticide exposure (over 3000 g/ha), there is a higher risk of a resulting disturbed oocyte cohort with a high prevalence of CLCG over 75%.The high prevalence of oocytes with CLCG over 75% has a negative effect on embryos and the general ICSI clinical outcomes. Furthermore, a putative association between pesticide exposure and risk of CLCG was identified, justifying the need for further research and a potential need to find alternative assisted reproductive technologies for these couples.
[Merviel P, Cabry R, Chardon K, Haraux E, et al. 2017. J Ovarian Res. 10(1):42.]
- In utero exposure to atrazine analytes and early menarche in the Avon Longitudinal Study of Parents and Children Cohort.
Evidence from experimental studies suggests that atrazine and its analytes alter the timing of puberty in laboratory animals. Such associations have not been investigated in humans. To determine the association between in utero exposure to atrazine analytes and earlier menarche attainment in a nested case-control study of the population-based Avon Longitudinal Study of Parents and Children. Cases were girls who reported menarche before 11.5 years while controls were girls who reported menarche at or after 11.5 years. Seven atrazine analyte concentrations were measured in maternal gestational urine samples (sample gestation week median (IQR): 12 (8-17)) during the period 1991-1992, for 174 cases and 195 controls using high-performance liquid chromatography-tandem mass spectrometry. We evaluated the study association using multivariate logistic regression, adjusting for potential confounders. We used multiple imputations to impute missing confounder data for 29% of the study participants. Diaminochlorotriazine (DACT) was the most frequently detected analyte (58%>limit of detection [LOD]) followed by desethyl atrazine (6%), desethyl atrazine mercapturate (3%), atrazine mercapturate (1%), hydroxyl atrazine (1%), atrazine (1%) and desisopropyl atrazine (0.5%). Because of low detection of other analytes, only DACT was included in the exposure-outcome analyses. The adjusted odds of early menarche for girls with DACT exposures≥median was 1.13 (95% Confidence Interval [95% CI]:0.82, 1.55) and exposure
[Namulanda G, Taylor E, Maisonet M, Boyd Barr D, et al. 2017. Environ Res. 156:420-425. ]
- Investigation of Associations Between Exposures to Pesticides and Testosterone Levels in Thai Farmers
We conducted a cross-sectional study to assess the relationship between pesticide exposures and testosterone levels in 133 male Thai farmers. Urine and serum samples were collected concurrently from participants. Urine was analyzed for levels of specific- and non-specific metabolites of organophosphates (OPs), pyrethroids, select herbicides, and fungicides. Serum was analyzed for total and free testosterone. Linear regression analyses revealed significant negative relationships between total testosterone and the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) after controlling for covariates (e.g., age, BMI, smoking status). Positive significant associations were found between some OP pesticides and total testosterone. Due to the small sample size and the observational nature of the study, future investigation is needed to confirm our results and to elucidate the biological mechanisms.
[Panuwet P, Ladva C, Barr DB, Prapamontol T, et al. 2017. Arch Environ Occup Health. doi: 10.1080/19338244.2017.1378606]
- Is it time to reassess current safety standards for glyphosate-based herbicides?
Use of glyphosate-based herbicides (GBHs) increased ∼100-fold from 1974 to 2014. Additional increases are expected due to widespread emergence of glyphosate-resistant weeds, increased application of GBHs, and preharvest uses of GBHs as desiccants. Current safety assessments rely heavily on studies conducted over 30 years ago. We have considered information on GBH use, exposures, mechanisms of action, toxicity and epidemiology. Human exposures to glyphosate are rising, and a number of in vitro and in vivo studies challenge the basis for the current safety assessment of glyphosate and GBHs. We conclude that current safety standards for GBHs are outdated and may fail to protect public health or the environment. To improve safety standards, the following are urgently needed: (1) human biomonitoring for glyphosate and its metabolites; (2) prioritisation of glyphosate and GBHs for hazard assessments, including toxicological studies that use state-of-the-art approaches; (3) epidemiological studies, especially of occupationally exposed agricultural workers, pregnant women and their children and (4) evaluations of GBHs in commercially used formulations, recognising that herbicide mixtures likely have effects that are not predicted by studying glyphosate alone.
[Vandenberg LN, Blumberg B, Antoniou MN, Benbrook CM, Carroll L, Colborn T, et al. 2017. J Epidemiol Community Health. 71(6):613-618]
- Low doses of chlorpyrifos interfere with spermatogenesis of rats through reduction of sex hormones.
Use of pesticides results in indirect effects on human health. We aimed to evaluate implications of toxicological effects of subchronic chlorpyrifos exposure on reproductive function in male rats. A total of 48 adult Wistar male rats were separated into four groups (n = 12). Animals were gavaged with 2.5 mg/kg (T1), 5 mg/kg (T2), or 10 mg/kg (T3) body weight of chlorpyrifos (CPF) or distilled water (control) daily for 30 days. Organ weights, epididymal sperm parameters, DNA integrity, sex hormonal (FHS and LH) levels, and alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), and creatinine concentrations were determined on day 31. Another two sets of (four groups/set; n = 10) animals were orally treated with the same doses of CPF, control animal groups were treated with distilled water only for 30 days, and fertility indices and blood plasma acetylcholine esterase (AchE) were determined on day 31. Exposure to CPF resulted in a significant (p < 0.05) decrease in weights of testis and epididymis. An increase in liver weight resulted in reduced sperm counts and sperm motility and an increase in sperm abnormalities. Significant reduction in serum testosterone (p < 0.01), luteinizing hormone (p < 0.05), and follicular stimulating hormone (p < 0.05) levels was evident in animals treated with the highest dose. A significant decrease in the number of viable implantation sites and pups was observed in female rats mated with the T3 (p < 0.01) and T2 (p < 0.05) males. The ALT, AST, GGT, and creatinine contents were significantly increased (p < 0.05 and p < 0.01, respectively) on CPF exposure. A significant (p < 0.01) reduction in blood plasma AchE enzyme was observed with the highest dose. Our results demonstrated that prolonged exposure of CPF induces spermatogenesis damage, possibly through interference with sex hormones and AchE enzyme resulting in reduction of fertility. Therefore, awareness programs on handling CPF (pesticides) to enhance safety warrant minimization of its hazards.
[Peiris DC, Dhanushka T. 2017. Environ Sci Pollut Res Int. doi: 10.1007/s11356-017-9617-x.]
- Maternal linuron exposure alters testicular development in male offspring rats at the whole genome level.
Linuron is a widely used herbicide; its toxicity on the male reproductive system has been recognized. The current study was designed to explore the molecular mechanism underlying linuron-induced reproductive toxicity. Pregnant rats received daily oral gavage of linuron at the dose of 120mg/kg/d from gestation day (GD)12 to GD17. Tissues from male offspring rats were collected for pathological examination and microarray gene expression profiling. Changes in gene expression were further verified by quantitative real-time RT-PCR. Data showed that linuron-exposed offspring rats had a decreased sperm count (88% of controls) and disrupted acrosome formation. There were evident damages in seminiferous tubules and abnormal morphology in mesenchymal cells in samples from linuron-exposed animals. Microarray analysis indicated that the expressions of testosterone synthesis-associated genes, i.e., Star, P450scc, 3β-Hsd, Abp, Cox7a2, Pcna, p450c17and17β-Hsd were significantly altered by linuron exposure, along with other genes involving in cell proliferation and apoptosis, such as c-myc, S6K, Apaf1, and TSC1. These data indicate that linuron upon entering male offspring body can directly or indirectly interact with the androgen production and function; linuron-induced alteration in genes encoding testosterone synthesis is likely a major factor in linuron-induced male reproductive toxicity.
[Bai J, Han H, Wang F, Su L, et al. 2017. Toxicology. 389:13-20]
- Occupational exposure to pesticides, reproductive hormone levels and sperm quality in young Brazilian men.
The association of occupational exposure to current-use pesticides with reproductive hormones, semen quality, and genital measures was investigated among young men in the South of Brazil. A cross-sectional study was conducted in 99 rural and 36 urban men aged 18-23 years. Information on pesticide use was obtained through questionnaire. Serum and semen samples were analyzed for sex hormones and sperm parameters, respectively, and measurement of anogenital distance (AGD) and testis volume (TV) were performed. Associations were explored using multivariate linear regression. Rural men had poorer sperm morphology, higher sperm count, and lower LH levels relative to urban subjects. Lifetime use of pesticides, especially herbicides and fungicides, was associated with poorer morphology and reduced LH and prolactin, with evidence of a linear pattern. Maternal farming during pregnancy was associated with larger AGD and TV. Chronic occupational exposure to modern pesticides may affect reproductive outcomes in young men.
[Cremonese C, Piccoli C, Pasqualotto F, Clapauch R, et al,. 2017. Reprod Toxicol. pii: S0890-6238(17)30006-0.]
- Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in human breast milk and associated health risks to nursing infants in Northern Tanzania
This is the first study to report organochlorines (OCs), including chlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) in human milk from Tanzania. The main aims of this study were to assess the level of contamination and the possible health risks related to OC exposure in nursing infants from the Northern parts of Tanzania. Ninety-five healthy mother-infant couples attending Mount Meru Regional Referral Hospital (MMRRH), Arusha, Tanzania, were assessed for associations between maternal/infant characteristics, i.e. mother's age, BMI, gestational weight gain, occupation, residence and fetal growth parameters and breast milk levels of OCPs, such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, dieldrin and PCBs. p,p'-DDE and p,p'-DDT were detected in 100% and 75% of the breast milk samples, respectively, and ranged between 24 and 2400ng/g lipid weight (lw) and
[Müller MH, Polder A, Brynildsrud OB, Karimi M, et al. 2017. Environ Res. 154:425-434]
- Pesticides: an update of human exposure and toxicity.
Pesticides are a family of compounds which have brought many benefits to mankind in the agricultural, industrial, and health areas, but their toxicities in both humans and animals have always been a concern. Regardless of acute poisonings which are common for some classes of pesticides like organophosphoruses, the association of chronic and sub-lethal exposure to pesticides with a prevalence of some persistent diseases is going to be a phenomenon to which global attention has been attracted. In this review, incidence of various malignant, neurodegenerative, respiratory, reproductive, developmental, and metabolic diseases in relation to different routes of human exposure to pesticides such as occupational, environmental, residential, parental, maternal, and paternal has been systematically criticized in different categories of pesticide toxicities like carcinogenicity, neurotoxicity, pulmonotoxicity, reproductive toxicity, developmental toxicity, and metabolic toxicity. A huge body of evidence exists on the possible role of pesticide exposures in the elevated incidence of human diseases such as cancers, Alzheimer, Parkinson, amyotrophic lateral sclerosis, asthma, bronchitis, infertility, birth defects, attention deficit hyperactivity disorder, autism, diabetes, and obesity. Most of the disorders are induced by insecticides and herbicides most notably organophosphorus, organochlorines, phenoxyacetic acids, and triazine compounds.
[Mostafalou S and Abdollahi M.2017. Arch Toxicol. 91(2):549-599]
- Prenatal and early postnatal NOAEL-dose clothianidin exposure leads to a reduction of germ cells in juvenile male mice.
Neonicotinoids are pesticides used worldwide. They bind to insect nicotinic acetylcholine receptors (nAChRs) with high affinity. We previously reported that clothianidin (CTD), one of the latest neonicotinoids, reduced antioxidant expression and induced germ cell death in the adult testis of vertebrates. Here, we investigated the male reproductive toxicity of prenatal and early postnatal exposure to CTD, because it is likely that developmental exposure more severely affects the testis compared to adults due to the absence of the blood-testis barrier. Pregnant C57BL/6 mice were given water gel blended with CTD (0, 10 or 50 mg/kg/day; no-observed-adverse-effect-level [NOAEL for mice]: 47.2 mg/kg/day) between gestational day 1 and 14 days post-partum. We then examined the testes of male offspring at postnatal day 14. The testis weights and the numbers of germ cells per seminiferous tubule were decreased in the CTD-50 group, and abnormal tubules containing no germ cells appeared. Nevertheless, the apoptotic cell number and proliferative activity were not significantly different between the control and CTD-exposed groups. There were no significant differences in the androgen-related parameters, such as the Leydig cell volume per testis, the Sertoli cell number and the tubule diameter. The present study is the first demonstration that in utero and lactational exposures to CTD at around the NOAEL for mice reduce the germ cell number, but our findings suggest that these exposures do not affect steroidogenesis in Leydig cells during prenatal or early postnatal life.
[Yanai S, Hirano T, Omotehara T, Takada T, et al. 2017. J Vet Med Sci. 79(7):1196-1203.]
- Relationship between pesticide exposure and adverse pregnancy outcomes among reproductive couples in rural areas of China
To analyze the association between pesticide exposure and adverse pregnancy outcomes in women from the rural areas of China. Data of "National Free Preconception Health Examination Project (NFPHEP)" from January 2010 to December 2012 was used for analysis. A total of 248 501 families that were planning to deliver a baby in the next 6 months were enrolled. Data on paternal exposure to pesticides before or during pregnancy was collected through questionnaires, with related outcomes on pregnancy recorded by doctors. Among all the 248 501 participants, 1 806 (0.74%) women and 2 653 (1.09%) men reported to have been exposed to pesticide before pregnancy, with 505 (0.21%) reported of having been exposed to pesticide during the period of pregnancy. Maternal exposure to pesticide was found a risk factor related to stillbirth (OR=3.37, 95%CI: 2.05-5.55), peculiar smell pregnancy (OR=3.17, 95%CI:1.18-8.55) and low birth weight (OR=7.56, 95% CI: 5.36-10.66). Paternal exposure to pesticide was also found related to miscarriage (OR=1.37, 95% CI: 1.03-1.80), low birth weight (OR=3.65, 95% CI:1.51-8.84), or giant infant (OR=0.64, 95%CI: 0.44-0.93). Maternal exposure to pesticide during pregnancy appeared a risk factor on miscarriage (OR=4.65, 95% CI: 3.47-6.24). Other adverse outcomes on pregnancy would include premature birth and high birth weight.Parental pesticide exposure appeared a risk factor on stillbirth, peculiar smell pregnancy, low birth weight and miscarriage.
[Qu YM, Chen S, Li JJ, Jin RR, et al. 2017. Zhonghua Liu Xing Bing Xue Za Zhi. 38(6):732-736]
- Reproductive toxic impact of subchronic treatment with combined butylparaben and triclosan in weanling male rats.
The effect of treatment with combined butylparaben and triclosan on male gonadal toxicity in weanling rats was investigated. All treated groups experienced atrophy in the ventral prostate and seminal vesicle, likewise significant depletion in the number and motility of sperm. Given individually or combined butylparaben and triclosan, significantly decreased testosterone, luteinizing hormone, and follicle‐stimulating hormone levels. Individual treatment with tested compounds caused significant elevation in the E2 level, whereas combined treatment did not alter the E2 level. Testicular DNA damage was recorded in all treated groups. Moreover, the testicular malondialdehyde level was significantly elevated, along with a significant decrease in catalase enzyme activity in all treated groups. Superoxide dismutase enzyme activity was significantly decreased in the butylparaben‐treated group, increased in the triclosan‐treated group, and nonsignificantly changed the butylparaben‐triclosan‐treated group. The combined treatment produced an endocrine disturbance with a concomitant induction of testicular oxidative stress, which may represent a common mechanism of endocrine disruptor‐mediated dysfunction.
[Riad, M et al. 2017. J Biochem Mol Toxicol doi:10.1002/jbt.22037.]
- Routine assessment of occupational exposure and its relation to semen quality in infertile men: a cross-sectional study.
Concerns about the detrimental effects of occupational and environmental exposure on male reproductive function have been raised by reports of declining sperm quality over the last decades. The aim of this study was to investigate the association between altered semen parameters and exposure to occupational risk factors as assessed by questionnaire.We conducted a cross-sectional questionnaire-based study among a population of 2122 men who underwent andrological investigation for couple infertility. All participants were interviewed and their semen samples were analyzed. Information about medical history and occupational exposure was used to classify participants into exposed and unexposed groups.Exposure to pesticides was associated with a significantly higher risk of asthenozoospermia (adjusted odds ratio [OR] = 1.6; 95% CI, 1.0-2.4) and necrozoospermia (OR = 2.6; 95% CI, 1.4-4.7). Exposure to cement was found to be correlated with a higher risk of oligozoospermia (OR = 1.1; 95% CI, 0.9-1.4). There was no association between semen impairment and exposure to solvents, excess heat, or mechanical vibrations.We found an association between self-reported occupational exposure and altered semen parameters. These results support the usefulness of questionnaires for routine assessment and management of occupational exposures in infertile men.
[Daoud S, Sellami A, Bouassida M, et al. 2017. Turk J Med Sci. 47(3):902-907.]
- The In Vitro Impact of the Herbicide Roundup on Human Sperm Motility and Sperm Mitochondria.
Toxicants, such as herbicides, have been hypothesized to affect sperm parameters. The most common method of exposure to herbicides is through spraying or diet. The aim of the present study was to investigate the effect of direct exposure of sperm to 1 mg/L of the herbicide Roundup on sperm motility and mitochondrial integrity. Sperm samples from 66 healthy men who were seeking semen analysis were investigated after written informed consent was taken. Semen analysis was performed according to the World Health Organization guidelines (WHO, 2010). Mitochondrial integrity was assessed through mitochondrial staining using a mitochondria-specific dye, which is exclusively incorporated into functionally active mitochondria. A quantity of 1 mg/L of Roundup was found to exert a deleterious effect on sperm's progressive motility, after 1 h of incubation (mean difference between treated and control samples = 11.2%) in comparison with the effect after three hours of incubation (mean difference = 6.33%, p < 0.05), while the relative incorporation of the mitochondrial dye in mitochondria of the mid-piece region of Roundup-treated spermatozoa was significantly reduced compared to relative controls at the first hour of incubation, indicating mitochondrial dysfunction by Roundup. Our results indicate that the direct exposure of semen samples to the active constituent of the herbicide Roundup at the relatively low concentration of 1 mg/L has adverse effects on sperm motility, and this may be related to the observed reduction in mitochondrial staining.
[Anifandis G, Amiridis G, Dafopoulos K, Daponte A, et al. 2017. Toxics. 6(1). pii: E2. doi: 10.3390/toxics6010002.]
- Association of organochlorine pesticides with the mRNA expression of tumour necrosis factor-alpha (TNF-α) & cyclooxygenase-2 (COX-2) genes in idiopathic preterm birth.
Preterm birth (PTB) is an important cause of prenatal death, neonatal morbidity and mortality and adult illness. Increased inflammation occurs in normal parturition, and inflammatory cytokines and oxidative stress are found to be higher in PTB cases. The present study was planned to investigate the association of organochlorine pesticides (OCPs) with mRNA expression of inflammatory pathway genes such as tumour necrosis factor-alpha (TNF-α) and cyclooxygenase-2 (COX-2) in preterm delivery (PTD) cases. Maternal blood samples of PTD (n=30) cases and equal number of term delivery (n=30) were collected at the time of labour.
Significantly higher levels of β-HCH (beta-hexachlorocyclohexane), p'p'-DDE (para, para-dichlorodiphenyldichloroethylene), and o'p'-DDD (ortho, para-dichlorodiphenyldichloroethane) were observed in maternal blood of PTB cases as compared to term delivery. The mRNA expressions of COX-2 and TNF-α genes were 3.13 and 2.31 folds higher in PTB cases in comparison to term delivery. l0 inear positive correlations were observed between period of gestation (POG) and ΔCt of COX-2 and TNF-α genes. Environmental factors such as OCPs may be associated with inflammatory events showing gene-environment interaction in PTB cases. Evaluating the molecular control of inflammation along with gene environment interaction may be used as a model to explore the aetiology of idiopathic PTB cases and may be considered for the prognosis of adverse reproductive outcomes.
[Tyagi V, Mustafa MD, Sharma T, et al. 2016. Indian J Med Res. 143(6):731-738. ]
- Effect of methomyl on the biochemical and reproductive parameters in pregnancy rats: the protective role of Pistacia Lentiscus oil
Methomyl (MET) is a carbamate insecticide used worldwide to protect a wide variety of crops from insect nuisances. Besides this beneficial role, it is classified as highly toxic compound for humans and animals by the EPA. Pistacia Lentiscus (PL) is a shrub that grows in the Mediterranean region; plant parts and oil have a long history in folk medicine in healing several diseases by their antioxidant, anti-inflammatory, antimicrobial, antifungal, antiatherogenic and anticancer properties. Hence, this study was undertaken to assess the effect of MET on biochemical, histological and reproductive parameters as well as the possible protective role of Pistacia Lentiscus oil (PLO) against MET-induced toxicity in pregnant female rats. Thirty two pregnant female rats were randomly divided into four equal groups including control, MET group (10 mg/kg/bw), PLO group (0.5 ml/kg/bw) and MET+ PLO group, MET and PLO were administered by oral route. At the eighteenth day of gestation (GD18), the blood samples were taken from retro-orbital sinus to evaluate the biochemical parameters and progesterone level. Then after the parturition, the different reproductive parameters were measured and the ovary and adrenal glands were removed, weighed, fixed and used for histopathological examination.The results show that MET increased significantly the weight of liver and adrenal gland, the level of cholesterol, glucose, creatinin, urea, ASAT and ALAT, meanwhile the level of total protein was reduced. Likewise, MET induced reproductive toxicity pronounced by a decline in the level of progesterone, an alteration in the reproductive index and an increase in the number of ovary atretic follicles and degenerative corpus luteum. The supplementation of the PLO with MET reverses partially and/or completely all adverse effects noted on the biochemical and reproductive parameters as well as on the histopathological changes by their antioxidant activities. We recommended the use of PLO by oral and/or dermal application as protective agent against several diseases related to reproduction dysfunction.
[Mosbah, R., Mokrani, N., Mosbahi, I., Rouabhi, S. and Mantovani, A., 2016. In 18th European Congress of Endocrinology (Vol. 41). BioScientifica.]
- Effect of Prenatal Exposure to Pesticides on Children's Health.
The aim of this study was to summarize the current state of knowledge on pesticide-related fertility problems and disadventeges of childrens due to prenatal pesticides exposure. Available literature was analyzed. Due to the extent of the issue, the study focuses on epidemiological studies conducted in humans, despite evidence from in vitro and animal studies. It seems certain that exposure to harmful chemicals is one of the factors that may cause a decline in fertility and problems with conceiving, whereas exposure during pregnancy can impair foetal development. Prenatal exposure may also result in the occurrence of childhood cancer and neurobehavioral disorders. The meaning of the project is to summarize the role of pesticides in the process of reproduction. This applies especially to people working in agriculture, since they might be occupationally exposed to pesticides.
[Matysiak M, Kruszewski M, Jodlowska-Jedrych B, Kapka-Skrzypczak L. 2016. J Environ Pathol Toxicol Oncol. 35(4):375-386.]
- Endocrine-Disrupting Chemicals and Reproductive Health.
This review discusses the evidence linking industrial chemicals to a variety of health and reproductive outcomes. Industrial chemical production has increased over the past 30 to 40 years. Basic science, animal models, and epidemiologic data suggest that certain chemicals may act as endocrine disruptors (substances that interfere with normal hormonal action) and may play an etiologic role in a number of conditions whose incidence has also increased during this same period. These include low birth weight, gestational diabetes, obesity, certain cancers, certain birth defects, and neurodevelopmental disorders such as attention deficit disorder and autism. In addition, some environmental chemicals may have epigenetic effects, resulting in transgenerational health impacts. The epidemiologic and experimental evidence that links chemicals such as plasticizers (eg, phthalates and phenols), flame retardants, perfluorinated compounds, and pesticides with adverse reproductive health outcomes is reviewed. Women's health care providers are the liaison between scientific research and their patients; they should educate themselves on the significance of environmental toxins to health. They are ideally positioned, not only to counsel and reassure pregnant women, but also to suggest practicable changes in dietary and lifestyle habits to improve their health. Furthermore, women's health care providers should advocate for regulatory changes that protect women and their families from the health effects of environmental toxins.
[Zlatnik MG. 2016. J Midwifery Womens Health. 61(4):442-55.]
- Epigenetic Effects Of Environmental Chemicals On Reproductive Biology
Mammalian reproduction is a complex phenomenon. Human fertility is highly impacted from environmental exposure to toxicants as well as nutrients. The burden of environmental stimuli is heavy and multifaceted. The contaminant sources are many, often occult, and at present, the wide range of positive and negative consequences on the ecosystem and the human health is only partially understood. Compounds deriving from industrial manufacturing, pesticides, waste accumulation and burning are only some examples of the contaminants daily impacting human life. Ovary and testis biology, primordial germinal cells and gametogenesis are primary targets of a large number of pollutants. Pregnancy holds the basis of the healthy post-natal life of each individual and his offspring. During the pre-natal development, genetic and epigenetic factors concur to determine the good sequence of events for the good final outcome of the pregnancy. World wide epidemiological studies and focused experiments in animal models are unraveling the molecular basis of the normal and abnormal development. Evidences are growing about the relationship between pregnancy conditions and the onset of metabolic and other complex diseases in adult life. Epigenetic mechanisms, including DNA methylation, histone marks and non coding RNAs, are main molecular players of normal development and of the adaptive response during pre- and post natal life.
[Strazzullo M and Matarazzo MR. 2016. Curr Drug Targets. Vol17]
- Glyphosate and adverse pregnancy outcomes, a systematic review of observational studies
A study in frog and chicken embryos, and reports of a high incidence of birth defects in regions of intensive GM-soy planting have raised concerns on the teratogenic potential of glyphosate-based herbicides. These public concerns prompted us to conduct a systematic review of the epidemiological studies testing hypotheses of associations between glyphosate exposure and adverse pregnancy outcomes including birth defects.A case-control study on the association between pesticides and congenital malformations in areas of extensive GM soy crops in South America, and reports on the occurrence of birth defects in these regions were reviewed. The search found ten studies testing associations between glyphosate and birth defects, abortions, pre-term deliveries, small for gestational date births, childhood diseases or altered sex ratios. Two additional studies examined changes of time-to-pregnancy in glyphosate-exposed populations. Except for an excess of Attention Deficit Hyperactivity Disorder - ADHD (OR = 3.6, 1.3-9.6) among children born to glyphosate appliers, no significant associations between this herbicide and adverse pregnancy outcomes were described. Evidence that in South American regions of intensive GM-soy planting incidence of birth defects is high remains elusive.Current epidemiological evidence, albeit limited to a few studies using non-quantitative and indirect estimates and dichotomous analysis of exposures, does not lend support to public concerns that glyphosate-based pesticides might pose developmental risks to the unborn child. Nonetheless, owing to methodological limitations of existing analytical observational studies, and particularly to a lack of a direct measurement (urine and/or blood levels), or an indirect estimation of exposure that has proven valid, these negative findings cannot be taken as definitive evidence that GLY, at current levels of occupational and environmental exposures, brings no risk for human development and reproduction.
[de Araujo JS, Delgado IF, Paumgartten FJ. 2016. BMC Public Health. 16:472]
- Glyphosate pathways to modern diseases V: Amino acid analogue of glycine in diverse proteins
Glyphosate, a synthetic amino acid and analogue of glycine, is the most widely used biocide on the planet. Its presence in food for human consumption and animal feed is ubiquitous. Epidemiological studies have revealed a strong correlation between the increasing incidence in the United States of a large number of chronic diseases and the increased use of glyphosate herbicide on corn, soy and wheat crops. Glyphosate, acting as a glycine analogue, may be mistakenly incorporated into peptides during protein synthesis. A deep search of the research literature has revealed a number of protein classes that depend on conserved glycine residues for proper function. Glycine, the smallest amino acid, has unique properties that support flexibility and the ability to anchor to the plasma membrane or the cytoskeleton. Glyphosate substitution for conserved glycines can easily explain a link with diabetes, obesity, asthma, chronic obstructive pulmonary disease (COPD), pulmonary edema, adrenal insufficiency, hypothyroidism, Alzheimer’s disease, amyotrophic lateral sclerosis (ALS), Parkinson’s disease, prion diseases, lupus, mitochondrial disease, nonHodgkin’s lymphoma, neural tube defects, infertility, hypertension, glaucoma, osteoporosis, fatty liver disease and kidney failure. The correlation data together with the direct biological evidence make a compelling case for glyphosate action as a glycine analogue to account for much of glyphosate’s toxicity. Glufosinate, an analogue of glutamate, likely exhibits an analogous toxicity mechanism. There is an urgent need to find an effective and economical way to grow crops without the use of glyphosate and glufosinate as herbicides.
[Samsel, A. and Seneff, S., 2016. J Biol Phys Chem, 16(6), pp.9-46.]
- Human exposure to endocrine disrupting compounds: Their role in reproductive systems, metabolic syndrome and breast cancer. A review
Endocrine disrupting chemicals (EDCs) are released into the environment from different sources. They are mainly used in packaging industries, pesticides and food constituents. Clinical evidence, experimental models, and epidemiological studies suggest that EDCs have major risks for humans by targeting different organs and systems in the body (e.g. reproductive system, breast tissue, adipose tissue, pancreas, etc.). Due to the ubiquity of human exposure to these compounds the aim of this review is to describe the most recent data on the effects induced by phthalates, bisphenol A and parabens in a critical window of exposure: in utero, during pregnancy, infants, and children. The interactions and mechanisms of toxicity of EDCs in relation to human general health problems, especially those broadening the term of endocrine disruption to 'metabolic disruption', should be deeply investigated. These include endocrine disturbances, with particular reference to reproductive problems and breast, testicular and ovarian cancers, and metabolic diseases such as obesity or diabetes.
[Giulivo M, Lopez de Alda M, Capri E, Barceló D. 2016. Environ Res. 151:251-264.]
- Individual and combined effect of chlorpyrifos and cypermethrin on reproductive system of adult male albino rats.
Commercial mixtures of chlorpyrifos and cypermethrin pesticides are widely used to enhance the toxic effects of cypermethrin on target insects. So, the purpose of the current study was to evaluate the individual and combined toxic effects of chlorpyrifos (CPF) and cypermethrin (CYP) on reproductive system of adult male albino rats. Forty adult male albino rats were randomized into main four groups. All treatments were given by oral gavage for 12 weeks. Single CPF and CYP exposures significantly have adverse effects on reproductive function of adult male albino rats manifested by reduced testicular weight, decreased sperm count, motility and viability, significantly increased percent of morphologically abnormal spermatozoa, and significant increments in sperm DNA fragmentation index (DFI) with respect to control group. Furthermore, serum follicle stimulating hormone, luteinizing hormone, and testosterone levels were decreased significantly compared to control group. This was accompanied with histopathological changes in the testis of rats such as necrosis, degeneration, decreasing number of spermatogenic cells in some seminiferous tubules, edema, congested blood vessels, and exudate in interstitial tissue of the testis. Notably, all these changes were exaggerated in rats treated concomitantly with chlorpyrifos and cypermethrin rendering the mixture more toxic than the additive effects of each compound and causing greater damage on the reproductive system of male albino rats than the individual pesticides.
[Alaa-Eldin EA, El-Shafei DA, Abouhashem NS. 2016. Environ Sci Pollut Res. doi:10.1007/s11356-016-7912-6]
- Myclobutanil worsens nonalcoholic fatty liver disease: An in vitro study of toxicity and apoptosis on HepG2 cells.
Myclobutanil is a conazole class fungicide widely used as an agrichemical. Its widespread use has raised the issue of possible health risks for agrarian communities and the general population, which can be exposed to residues present in food and drinking water. The toxicities identified include adverse effects on liver and kidney and on the development of male reproductive organs. Since the liver is the first-line organ in the defense against xenobiotics, toxic effects on hepatic metabolism cause degeneration, necrosis, and tissue hypertrophy. Therefore, we investigated myclobutanil's effects on the human liver cell line HepG2. We found that myclobutanil increases the amount of fatty acids in these hepatic cells, as evaluated with Oil Red O staining, and progressively reduces cell viability from 1ppm to 500ppm. Analysis of biomarkers such as Bcl-xL/Bak and Mcl-1/Bak confirmed activation of cell death pathways at low doses. Therefore, myclobutanil may play an important role in the pathogenesis and progression of chronic hepatocellular diseases in humans.
[Stellavato A, Lamberti M, Pirozzi AV, et al. 2016. Toxicol Lett. 262:100-104]
- Occupational exposure to pesticides as a possible risk factor for the development of chronic diseases in humans (Review).
It is well known that pesticides are widely used compounds. In fact, their use in agriculture, forestry, fishery and the food industry has granted a huge improvement in terms of productive efficiency. However, a great number of epidemiological surveys have demonstrated that these toxic compounds can interact and exert negative effects not only with their targets (pests, herbs and fungi), but also with the rest of the environment, including humans. This is particularly relevant in the case of workers involved in the production, transportation, preparation and application of these toxicants. Accordingly, a growing body of evidence has demonstrated the correlation between occupational exposure to pesticides and the development of a wide spectrum of pathologies, ranging from eczema to neurological diseases and cancer. Pesticide exposure is often quite difficult to establish, as many currently used modules do not take into account all of the many variables that can occur in a diverse environment, such as the agricultural sector, and the assessment of the real risk for every single worker is problematic. Indeed, the use of personal protection equipment is necessary while handling these toxic compounds, but education of workers can be even more important: personal contamination with pesticides may occur even in apparently harmless situations. This review summarises the most recent findings describing the association between pesticide occupational exposure and the development of chronic diseases.
[Gangemi S, Miozzi E, Teodoro M, Briguglio G, et al. 2016. Mol Med Rep. 14(5):4475-4488. ]
- Prenatal Paraquat exposure induces neurobehavioral and cognitive changes in mice offspring.
In the present work, we investigated developmental toxicity of Paraquat (PQ), from the 1st or 6th day of mating and throughout the gestation period. We have examined several parameters, including toxicity indices, reproductive performance, sensorimotor development, as well as anxiety and cognitive performance of the offspring. Our results showed that exposure to 20mg/kg of Paraquat during the first days of pregnancy completely prevents pregnancy in treated mice, but from the 6th day of pregnancy, an alteration in fertility and reproductive parameters was observed. In offspring, the PQ was responsible for an overall delay of innate reflexes and a deficit in motor development. All exposed animals showed a decrease in the level of locomotor activity, increased levels of anxiety-like behavior and pronounced cognitive impairment in adulthood. These results demonstrated that Paraquat led to the onset of many behavioral changes that stem from the impairment of neuronal developmental processes in prenatally exposed mice.
[Ait-Bali Y, Ba-M'hamed S, Bennis M. 2016. Environ Toxicol Pharmacol. 48:53-62.]
- The effects of alpha-cypermethrin exposure on biochemical and redox parameters in pregnant rats and their newborns.
Pyrethroid insecticides are extensively used in agriculture and in household activities. During pregnancy, they might affect maternal metabolic status and there after fetal development. In this work, authors studied metabolic and redox effects of low dose alpha-cypermethrin exposure in pregnant rats and their offspring. The diet containing alpha cypermethrin at 0.02mg/kg/day was consumed during the entire gestation. Plasma biochemical parameters as well as liver lipid and oxidative stress markers were determined. Results showed that alpha-cypermethrin induced an increase in body weight and in plasma glucose and lipid levels, as well as in plasma aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase activities in pregnant rats and their newborns. Pregnant rats showed cellular oxidative stress and altered oxidant-antioxidant status when treated by the insecticide and these disturbances were also seen in their newborns. In conclusion, low dose alpha-cypermethrin exposure induced several metabolic and redox alterations leading to maternal physiological impairments and to fetal metabolic changes. Alpha-cypermethrin should be used with caution especially during pregnancy.
[Hocine L, Merzouk H, Merzouk SA, et al. 2016. Pestic Biochem Physiol. 134:49-54]
- The Increasing Prevalence in Intersex Variation from Toxicological Dysregulation in Fetal Reproductive Tissue Differentiation and Development by Endocrine-Disrupting Chemicals
An increasing number of children are born with intersex variation (IV; ambiguous genitalia/hermaphrodite, pseudohermaphroditism, etc.). Evidence shows that endocrine-disrupting chemicals (EDCs) in the environment can cause reproductive variation through dysregulation of normal reproductive tissue differentiation, growth, and maturation if the fetus is exposed to EDCs during critical developmental times in utero. Animal studies support fish and reptile embryos exhibited IV and sex reversal when exposed to EDCs. Occupational studies verified higher prevalence of offspring with IV in chemically exposed workers (male and female). Chemicals associated with endocrine-disrupting ability in humans include organochlorine pesticides, poly-chlorinated biphenyls, bisphenol A, phthalates, dioxins, and furans. Intersex individuals may have concurrent physical disorders requiring lifelong medical intervention and experience gender dysphoria. An urgent need exists to determine which chemicals possess the greatest risk for IV and the mechanisms by which these chemicals are capable of interfering with normal physiological development in children.
[Rich AL, Phipps LM, Tiwari S, et al. 2016. Environ Health Insights. 10:163-71. ]
- Absence of effects on the rat sperm quality after subacute exposure to low doses of fungicide prochloraz.
Prochloraz (PCZ) is a fungicide and androgen-receptor antagonist used worldwide in horticulture and agriculture. Pre- and perinatal exposure to this pesticide during sexual differentiation is deleterious for male offspring. Since data on the effects of PCZ on epididymal functions are scarce, and because sperm maturation occurs in this organ, the present investigation aimed to determine whether low PCZ doses administered to rats during the phase of sperm transit through the epididymis might affect the morphophysiology of this organ and sperm quality. Adult male Wistar rats were assigned to 4 different groups: 0 (control, vehicle) or 10, 15, or 30 mg/kg bw/d PCZ diluted in corn oil administered orally for 4 consecutive days. Morphofunctional parameters of the male reproductive tract, hormone concentrations, sperm evaluations, and fertility and histopathologic analysis of testis and epididymis were assessed. There were no statistically significant differences between treated and control groups in relation to all evaluated parameters. Data demonstrated show that PCZ exposure for a brief 4-d exposure and low doses did not produce reproductive toxicity or compromise sperm quality in adult rats.
[Sanabria M, Pessin A, Zanutto MR, et al. 2015. J Toxicol Environ Health A. 78(8):481-91.]
- Anti-Müllerian hormone and lifestyle, reproductive, and environmental factors among women in rural South Africa.
Few data exist regarding anti-Müllerian hormone, a marker of ovarian reserve, in relation to environmental factors with potential ovarian toxicity. This analysis included 420 women from Limpopo, South Africa studied in 2010-2011. Women were administered comprehensive questionnaires, and plasma concentrations of anti-Müllerian hormone and dichlorodiphenyltrichloroethane were determined. The median age of women was 24 years; the median anti-Müllerian hormone concentration was 3.1 ng/ml. Women who reported indoor residual spraying in homes with painted walls (indicative of exposure to pyrethroids) had 25% lower anti-Müllerian hormone concentrations compared with women who reported no spraying. Little evidence of decreased anti-Müllerian hormone concentrations was observed among women with the highest dichlorodiphenyltrichloroethane levels. These are among the first data regarding anti-Müllerian hormone concentrations relative to pesticides and indoor air pollution. Our results are suggestive of decreased ovarian reserve associated with exposure to pyrethroid pesticides, which is consistent with laboratory animal data.
[Whitworth KW, Baird DD, Steiner AZ, et al.2015. Epidemiology.26(3):429-35.]
- Combined effects of repeated administration of Bretmont Wipeout (glyphosate) and Ultrazin (atrazine) on testosterone, oxidative stress and sperm quality of Wistar rats.
The potential toxicity resulting from the possible interactions of the herbicides, Ultrazin (atrazine, ATZ) and Bretmont Wipeout (glyphosate, GLY) is not completely known. This study evaluated reproductive- and hepato-toxicity in rats co-exposed to ATZ and GLY.Six weeks old male rats were exposed by gavage three times per week to ATZ (12.5 mg/kg) or GLY (5 mg/kg) alone or in combination (12.5 mg/kg ATZ + 5 mg/kg GLY).ATZ and GLY impaired sperm quality but GLY has more adverse effect on sperm quality than ATZ. Testosterone level, sperm motility, sperm counts, live/dead ratio and the weight of the epididymis were lower in the GLY group compared to the ATZ group by 57%, 33%, 20%, 22% and 41% and higher by 109%, 76.7%, 39.6%, 32.3% and 100% respectively in the combine-exposure group (ATZ + GLY) compared to the GLY group. Oxidative stress and histopathological changes were also noticeable in the liver but not in the testis of GLY-treated animals, and the observed effects were more remarkable in the GLY group than the ATZ or the combined-exposure group. The combined effects of the active ingredients on testosterone level, sperm count and hepatic malondialdehyde (MDA) levels were also similar as when the commercial formulations were used. Study finds antagonistic interactions between the two toxicants on the toxicity endpoints investigated in this study and these effects are due to the active ingredients of both herbicides in the commercial formulations.
[Abarikwu SO, Akiri OF, et al. 2015. Toxicol Mech Methods.25(1):70-80.]
- EDC-2: The Endocrine Society's Second Scientific Statement on Endocrine-Disrupting Chemicals.
The Endocrine Society's first Scientific Statement in 2009 provided a wake-up call to the scientific community about how environmental endocrine-disrupting chemicals (EDCs) affect health and disease. Five years later, a substantially larger body of literature has solidified our understanding of plausible mechanisms underlying EDC actions and how exposures in animals and humans-especially during development-may lay the foundations for disease later in life. At this point in history, we have much stronger knowledge about how EDCs alter gene-environment interactions via physiological, cellular, molecular, and epigenetic changes, thereby producing effects in exposed individuals as well as their descendants. Causal links between exposure and manifestation of disease are substantiated by experimental animal models and are consistent with correlative epidemiological data in humans. There are several caveats because differences in how experimental animal work is conducted can lead to difficulties in drawing broad conclusions, and we must continue to be cautious about inferring causality in humans. In this second Scientific Statement, we reviewed the literature on a subset of topics for which the translational evidence is strongest: 1) obesity and diabetes; 2) female reproduction; 3) male reproduction; 4) hormone-sensitive cancers in females; 5) prostate; 6) thyroid; and 7) neurodevelopment and neuroendocrine systems. Our inclusion criteria for studies were those conducted predominantly in the past 5 years deemed to be of high quality based on appropriate negative and positive control groups or populations, adequate sample size and experimental design, and mammalian animal studies with exposure levels in a range that was relevant to humans. We also focused on studies using the developmental origins of health and disease model. No report was excluded based on a positive or negative effect of the EDC exposure. The bulk of the results across the board strengthen the evidence for endocrine health-related actions of EDCs. Based on this much more complete understanding of the endocrine principles by which EDCs act, including nonmonotonic dose-responses, low-dose effects, and developmental vulnerability, these findings can be much better translated to human health. Armed with this information, researchers, physicians, and other healthcare providers can guide regulators and policymakers as they make responsible decisions.
[Gore AC, Chappell VA, Fenton SE, Flaws JA, et al. 2015. Endocr Rev. 36(6):E1-E150.]
- Effects of a mixture of pesticides on the adult female reproductive system of Sprague-Dawley, Wistar, and Lewis rats
The Brazilian federal government Agency for Health Surveillance detected pesticide residues in fresh food available for consumers all over the country. The current study investigated the effects of a mixture of some of those pesticides (dichlorvos, dicofol, dieldrin, endosulfan, and permethrin) on the reproductive system of Sprague-Dawley (SD), Wistar (WT), and Lewis (LEW) rats. Female rats from each strain were randomized into three experimental groups and were fed a control diet or diets added with pesticides mixture at their respective no-observed-effect level (NOEL)/no-observed-adverse-effect level (NOAEL) (low dose) (mg/kg/d): dichlorvos (0.23), dicofol (0.5), dieldrin (0.025), endosulfan (0.7), permethrin (5), or lowest-observed-effect level (LOEL)/lowest-effect level (LEL)/ lowest-observed-adverse-effect level (LOAEL) (toxically effective dose) (mg/kg/d): dichlorvos (2.3), dicofol (2.1), dieldrin (0.05), endosulfan (3.8), and permethrin (25) as reported in the literature. Euthanasia was performed between wk 10 and 12, during the estrous stage. Decreased body weights gain (SD and WT) and increased liver weights (SD, WT, and LEW) were observed in each strain fed the pesticides mixture at the higher levels. At that dose level, rat strains also varied in their responses regarding the estrous cycle, hormonal levels, and number of developing ovarian follicles. The studied mixture of pesticides was found to interfere with the female reproductive system when individual pesticides were mixed above a certain level, indicating a threshold exists for each of the strains studied.
[Pascotto VM, Guerra MT, Franci JA, et al. 2015. J Toxicol Environ Health A. 78(9):602-16]
- Leydig cell number and sperm production decrease induced by chronic ametryn exposure: a negative impact on animal reproductive health.
Ametryn is an herbicide used to control broadleaf and grass weeds and its acute and chronic toxicity is expected to be low. Since toxicological data on ametryn is scarce, the aim of this study was to evaluate rat reproductive toxicity. Thirty-six adult male Wistar rats (90 days) were divided into three groups: Co (control) and T1 and T2 exposed to 15 and 30 mg/kg/day of ametryn, respectively, for 56 days. Testicular analysis demonstrated that ametryn decreased sperm number per testis, daily sperm production, and Leydig cell number in both treated groups, although little perceptible morphological change has been observed in seminiferous tubule structure. Lipid peroxidation was higher in group T2, catalase activity decreased in T1 group, superoxide dismutase activity diminished, and a smaller number of sulphydryl groups of total proteins were verified in both exposed groups, suggesting oxidative stress. These results showed negative ametryn influence on the testes and can compromise animal reproductive performance and survival.
[Dantas TA, Cancian G, Neodini DN, et al. 2015. Environ Sci Pollut Res Int. 22(11):8526-35.]
- Prenatal exposure to PCB-153, p,p'-DDE and birth outcomes in 9000 mother-child pairs: exposure-response relationship and effect modifiers.
Low-level exposure to polychlorinated biphenyl-153 (PCB-153) and dichlorodiphenyldichloroethylene (p-p'-DDE) can impair fetal growth; however, the exposure-response relationship and effect modifiers of such association are not well established. This study is an extension of an earlier European meta-analysis. The aim was to explore exposure-response relationship between PCB-153 and p-p'-DDE and birth outcomes; to evaluate whether any no exposure-effect level and susceptible subgroups exist; and to assess the role of maternal gestational weight gain (GWG). A pooled dataset of 9377 mother-child pairs enrolled in 14 study populations from 11 European birth cohorts was used. Study found an inverse linear exposure-response relationship between prenatal exposure to PCB-153 and birth weight, and effects on birth weight over the entire exposure range, including at low levels. This reduction seems to be stronger among children of mothers who were non-Caucasian or had smoked during pregnancy. This study suggests that the association between low-level exposure to PCB-153 and birth weight exists and follows an inverse linear exposure-response relationship with effects even at low levels, and that maternal smoking and ethnicity modify this association.
[Casas M, Nieuwenhuijsen M, Martínez D, et al. 2015. Environ Int. 74:23-31]
- Impaired development of female mouse offspring maternally exposed to simazine
Authors evaluated the toxicity of simazine in female mouse offspring with in utero and lactational exposure. Pregnant mice were exposed to environmentally relevant doses (from 5 to 500μg/kg) of simazine via oral administration, and their female offspring were then analyzed. The female offspring showed shortened anogenital distance and decreased whole body, ovarian, and uterine weights. Their ovaries showed increased apoptotic granulosa cells. In addition, expression of critical genes involved in regulation of cellular apoptosis and proliferation was significantly downregulated in the ovaries of simazine-exposed mice. Moreover, in vitro exposure of human granulosa cell-derived KGN cells to simazine (0.003-1nM) resulted in decreased viability and proliferation. Thus, the present study demonstrates that maternal exposure to low doses of simazine impairs normal development of female offspring via disturbance of cellular apoptosis and proliferation.
[Park S, Kim S, et al. 2014. Environ Toxicol Pharmacol. 38(3):845-51]
- Methamidophos alters sperm function and DNA at different stages of spermatogenesis in mice.
Methamidophos (MET) is a highly toxic organophosphate (OP) pesticide that is widely used in developing countries. MET has male reproductive effects, including decreased fertility. We evaluated MET effects on sperm quality, fertilization and DNA integrity, exploring the sensitivity of different stages of spermatogenesis. Adult male mice were exposed to evaluate MET's effects on epididymal maturation, meiosis or mitosis, respectively. At 1-days post-treatment (dpt), MET inhibited AChE (43-57%) and increased abnormal cells (6%). While at 28- and 45-dpt, sperm motility and viability were significantly reduced, and abnormal morphology increased. MDA and mitochondrial activity were not affected at any dose or time. DNA damage (OTM and %DNA) was also observed. Sperm phosphorylation (at serine and tyrosine residues) was observed at all time points. Data suggest that meiosis and mitosis are the more sensitive stages of spermatogenesis for MET reproductive toxicity compared to epididymal maturation.
[Urióstegui-Acosta M, Hernández-Ochoa I, Sánchez-Gutiérrez M,et al. 2014. Toxicol Appl Pharmacol. 279(3):391-400]
- Persistent organochlorine pollutants and human reproductive health
Study focuses on the reproductive health effects in humans from four diverse populations: an Inuit population from Greenland, a Swedish population of fishermen and fishermen's wives, and urban populations from the cities of Warsaw in Poland and Kharkiv in Ukraine, representing populations with considerable variations in organochlorine exposure levels due to differences in the consumption of contaminated food items and the period since banning the use of the organochlorines selected in the present study. Time to pregnancy varied between the populations included, whereas semen quality was remarkably similar with only minor differences in motility between countries and within regions in Greenland. Sperm concentration and morphology were not associated with PCB-153 or DDE exposure, but sperm motility was consistently associated with PCB-153 exposure across populations. Xeno-estrogen, -androgen and dioxin-like activity in serum samples were not consistently associated with semen quality measures, indicating that the associations observed with sperm motility were not caused via direct effects on these receptors. Results suggest a higher probability of ever having a spontaneous abortion among women with high PCB-153 or DDE exposure levels. Overall, the results suggest that PCB-153, but probably not DDE, may affect aspects of male and female reproductive functioning in European and Arctic populations at the levels of exposure currently experienced in these populations, although the associations observed did not seem to be a major cause of reduced human fertility.
[Toft G. 2014. Dan Med J. 61(11):B4967.]
- Pesticide methoxychlor promotes the epigenetic transgenerational inheritance of adult-onset disease through the female germline.
This study examined the actions of the pesticide methoxychlor to promote the epigenetic transgenerational inheritance of adult-onset disease and associated differential DNA methylation regions (i.e. epimutations) in sperm. Gestating F0 generation female rats were transiently exposed to methoxychlor during fetal gonadal development (gestation days 8 to 14) and then adult-onset disease was evaluated in adult F1 and F3 (great-grand offspring) generation progeny for control (vehicle exposed) and methoxychlor lineage offspring. There were increases in the incidence of kidney disease, ovary disease, and obesity in the methoxychlor lineage animals. In females and males the incidence of disease increased in both the F1 and the F3 generations and the incidence of multiple disease increased in the F3 generation. There was increased disease incidence in F4 generation reverse outcross (female) offspring indicating disease transmission was primarily transmitted through the female germline. Analysis of the F3 generation sperm epigenome of the methoxychlor lineage males identified differentially DNA methylated regions (DMR) termed epimutations in a genome-wide gene promoters analysis. These epimutations were found to be methoxychlor exposure specific in comparison with other exposure specific sperm epimutation signatures. Observations indicate that the pesticide methoxychlor has the potential to promote the epigenetic transgenerational inheritance of disease and the sperm epimutations appear to provide exposure specific epigenetic biomarkers for transgenerational disease and ancestral environmental exposures.
[Manikkam M, Haque MM, et al. 2014. PLoS One. 24;9(7):e102091.]
- Prepubertal organochlorine pesticide concentrations and age of pubertal onset among Russian boys.
In animal studies, organochlorine pesticide (OCP) exposure alters pubertal development; however, epidemiological data are limited and inconsistent. The aim of this study was to evaluate the associations of serum OCP concentrations [hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH), and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE)] with male pubertal onset. In Chapaevsk, Russia, a town environmentally contaminated with OCPs, 350 8-9year old boys with measured OCPs were enrolled during 2003-2005 and were followed annually for eight years. The authors evaluated three measures of pubertal onset: testicular volume (TV)>3mL in either testis, or stage 2 or greater for genitalia (G2+), or pubic hair (P2+). In adjusted models, boys with higher HCB concentrations had later mean ages of TV>3mL and P2+ (but not G2+). Mean age at attaining TV>3mL was delayed 3.6, 7.9, and 4.7months for HCB Q2, Q3, and Q4, respectively, compared to Q1. Boys with higher HCB concentrations reached P2+ 0.1months earlier for Q2, 4.7months later for Q3 and 4.6months later for Q4 compared to Q1. There were no associations of serum β-HCH and p,p'-DDE concentrations with age of pubertal onset. Higher prepubertal serum HCB concentrations were associated with later age of gonadarche and pubarche.
[Lam T, Williams PL, Lee MM, et al. 2014. Environ Int. 73C:135-142.]
- Reproductive toxicities of methoxychlor based on estrogenic properties of the compound and its estrogenic metabolite, hydroxyphenyltrichloroethane.
Methoxychlor is an organochlorine pesticide having a weak estrogenicity, which is estimated to be approximately 1000- to 14,000-fold less potent to a natural ligand, 17β-estradiol. However, its active metabolite, hydroxyphenyltrichloroethane, has much more potent estrogenic activity and probably acts in the target organs of animals exposed to methoxychlor at least 100 times stronger than the parent compound. A variety of in vivo reproductive toxicity studies have shown that treatment with methoxychlor exerts typical endocrine-disrupting effects manifest as estrogenic effects, such as formation of cystic ovaries resulting in ovulation failures, uterine hypertrophy, hormonal imbalances, atrophy of male sexual organs, and deteriorations of sperm production in rats and/or mice, through which it causes serious reproductive damages in both sexes of animals at sufficient dose levels. However, methoxychlor is not teratogenic. The no-observed-adverse-effect level of methoxychlor among reliable experimental animal studies in terms of the reproductive toxicity is 10ppm (equivalent to 0.600mg/kg/day) in a two-generation reproduction toxicity study.
[Aoyama H, Chapin RE. 2014. Vitam Horm.94:193-210.]
- Subacute toxicity assessment of diflubenzuron, an insect growth regulator, in adult male rats.
The objective of the present study was to evaluate the toxicological effects of subacute exposure to Diflubenzuron (DFB) insecticide in adult male rats. Adult male rats were exposed (gavage) to 0, 2, 4, or 8 mg/kg of DFB for 28 days. No clinical signs of toxicity were observed in the DFB-treated animals of the experimental groups. However, there was an increase in serum levels of alanine aminotransferase in the group that received 8 mg/kg/DFB/day and urea at doses of 4 and 8 mg/kg/DFB/day, without altering other biochemical or hematological parameters. The subacute exposure to the lowest dose of DFB caused significant decrease in testis weight, daily sperm production, and in number of sperm in the epididymis in relation to the control group. However, no alterations were observed in the sperm morphology, testicular, epididymis, liver and kidney histology, or testosterone levels. These findings unveiled the hazardous effects of DFB on male reproduction after the subacute exposure and special attention should be addressed to the effects of low doses of this pesticide.
[de Barros AL, Cavalheiro GF, de Souza AV, et al, 2014. Environ Toxicol. doi: 10.1002/tox.22054.]
- Ancestral dichlorodiphenyltrichloroethane (DDT) exposure promotes epigenetic transgenerational inheritance of obesity.
Ancestral environmental exposures to a variety of environmental factors and toxicants have been shown to promote the epigenetic transgenerational inheritance of adult-onset disease. The present work examined the potential transgenerational actions of the insecticide dichlorodiphenyltrichloroethane (DDT) on obesity and associated disease. Outbred gestating female rats were transiently exposed to vehicle control or DDT and the F3 generation male sperm were collected to investigate methylation between the control and DDT lineage male sperm. The F1 generation DDT lineage animals did develop kidney disease, prostate disease, ovary disease and tumor development as adults. The F3 generation (great grand-offspring) had over 50% of males and females develop obesity. Several transgenerational diseases previously shown to be associated with metabolic syndrome and obesity were observed in the testis, ovary and kidney. The transgenerational transmission of disease was through both female (egg) and male (sperm) germlines. F3 generation sperm epimutations, differential DNA methylation regions (DMR), induced by DDT were identified. A number of the genes associated with the DMR have previously been shown to be associated with obesity. Observations indicate ancestral exposure to DDT can promote obesity and associated disease transgenerationally. The etiology of diseases such as obesity may be in part due to environmentally induced epigenetic transgenerational inheritance.
[Skinner MK, Manikkam M, Tracey R, et al.2013. BMC Med. 23;11:228.]
- Association between serum levels of organochlorine pesticides and sex hormones in adults living in a heavily contaminated area in Brazil.
The study examined the association between serum concentrations of organochlorine (OC) pesticides and levels of sex hormones in adult population in a rural area in Brazil heavily contaminated with these pesticides. A cross-sectional study with 304 men and 300 women was undertaken. Wet weight serum concentrations of 19 OC pesticides (dichloro-diphenyl-trichloroethane [DDT] and hexachlorocyclohexane [HCH], among others) were determined in all participants. Testosterone levels were obtained for men and estradiol, progesterone, prolactin, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) for women. After adjusting for serum lipids and confounders, heptachlor and o,p'-DDT concentrations in men were associated with lower testosterone levels, while peri- and postmenopausal women showed inverse associations between LH and hexachlorobenzene (HCB), p,p'-DDT, p,p'-DDD (dichloro-diphenyl-dichloroethane), endosulfan 1 and 2, aldrin and mirex, as well as between FSH and p,p'-DDD, endosulfan 1 and aldrin. Premenopausal women did not show statistically significant associations between OC pesticides and sex hormones.Thus,inverse associations between OC pesticide concentrations and testosterone in men and LH and FSH in peri-/postmenopausal women, together with the high proportion of women with elevated prolactin, suggest that these OC compounds may have triggered anti-androgenic effects in men and estrogenic effects in women in this population.
[Freire C, Koifman RJ, Sarcinelli PN, et al. 2013. Int J Hyg Environ Health. pii: S1438-4639(13)00106-5]
- Cypermethrin induced pathological and biochemical changes in reproductive organs of female rats.
Cypermethrin, a synthetic pyrethroid, has broad spectrum use in domestic agriculture, and veterinary applications due to its high bioefficacy, enhanced stability and low mammalian toxicity. The present investigation was performed to investigate the sub acute effects of cypermethrin in female rats. Cypermethrin at a dose of 50 mg kg(-1) body weight (1/5th LD50) was orally given to female rats for 4 weeks. Control rats received similar amount of ground nut oil. Significant decrease in ovarian weight (15.4%) was observed after four weeks of cypermethrin administration while the uterine weight (68.2%) and thickness of myometrium increased at 2 and 4 weeks. Cypermethrin caused degenerative changes in ovary as evidenced by increased follicular atresia and decreased concentration of proteins (38%), lipids (20%), phospholipids (18%) and cholesterol (37%). Acid (49.2%) and alkaline phosphatase (41%) activities were increased while lactate dehydrogenase (37.9%) and 3beta-HSDH (31.3%) decreased in treated rat ovary.
[Sangha GK, Kaur K, Khera KS. 2013. J Environ Biol. 34(1):99-105]
- Do in utero events contribute to current health disparities in reproductive medicine?
Health disparities exist in reproductive medicine as discussed in detail in the subsequent articles of this issue; however, in most cases, the exact cause of these differences is unknown. Some of these disparities can be linked to environmental exposures such as alcohol and other hazardous toxic exposures (polycarbonate, pesticides, nicotine) in adults. In addition, low socioeconomic status, behavioral risk factors, and lack of education have been linked to poor obstetric and reproductive outcomes in minority groups. Aside from these various environmental exposures later in life, there is evidence that adverse events in utero could contribute to poor reproductive outcome in specific minority groups. We will focus on the developmental origins of health and disease as a possible causal mechanism for health disparities in reproductive diseases, as this perspective may suggest tractable solutions of how to address and eliminate these health disparities.
[Sauerbrun-Cutler MT, Segars JH. 2013. Semin Reprod Med. 31(5):325-32]
- Endocrine-Disrupting contaminant mixtures induce adverse developmental effects in pre-weaning rats.
Reproductive toxicity was investigated in rats after developmental exposure to a mixture of 13 endocrine disrupting contaminants, including pesticides, plastic- and cosmetic ingredients, and paracetamol. ll exposures and a vehicle were administered by oral gavage to time-mated Wistar dams rats throughout gestation and lactation, and their offspring were assessed for reproductive effects at birth and in prepuberty.The mixture doses which included the anti-androgenic compounds, affected the male offspring by causing decreased anogenital distance, increased nipple retention and reduced ventral prostate weights, at both medium and high doses. Additionally, the weights of the levator ani/bulbocavernosus muscle (LABC) were decreased at the high anti-androgen mixture dose. No effects were seen after exposure to the estrogenic chemicals alone, whereas males exposed solely to paracetamol showed decreased LABC weights and increased nipple retention. Thus adverse reproductive effects were observed at mixtures reflecting 200 times high end human exposure, which is relatively close to the safety margin covered by the regulatory uncertainty factor of 100. This suggests that highly exposed human population groups may not be sufficiently protected against mixtures of endocrine disrupting chemicals.
[Axelstad M, Christiansen S, Boberg J,et al. 2013. Reproduction. doi: 10.1530/REP-13-0447]
- Environmental and occupational pesticide exposure and human sperm parameters: a systematic review.
Of continuing concern are the associations between environmental or occupational exposures to pesticides and semen quality parameters. Prior research has indicated that there may be associations between exposure to pesticides of a variety of classes and decreased sperm health. The intent of this review was to summarize the most recent evidence related to pesticide exposures and commonly used semen quality parameters, including concentration, motility and morphology. Included in the review are 17 studies, 15 of which reported significant associations between exposure to pesticides and semen quality indicators. Specific pesticides targeted for study included dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexane (HCH), and abamectin. Pyrethroids and organophosphates were analyzed as classes of pesticides rather than as individual compounds, primarily due to the limitations of exposure assessment techniques. Overall, a majority of the studies reported significant associations between pesticide exposure and sperm parameters. A decrease in sperm concentration was the most commonly reported finding among all of the pesticide classes investigated. Decreased motility was also associated with exposures to each of the pesticide classes, although these findings were less frequent across studies. The evidence presented in this review continues to support the hypothesis that exposures to pesticides at environmentally or occupationally relevant levels may be associated with decreased sperm health.
[Martenies SE, Perry MJ. 2013. Toxicology.307:66-73]
- Environmental contaminant exposures and preterm birth: a comprehensive review.
Preterm birth is a significant public health concern, as it is associated with high risk of infant mortality, various morbidities in both the neonatal period and later in life, and a significant societal economic burden. As many cases are of unknown etiology, identification of the contribution of environmental contaminant exposures is a priority in the study of preterm birth. This is a comprehensive review of all known studies published from 1992 through August 2012 linking maternal exposure to environmental chemicals during pregnancy with preterm birth. Using PubMed searches, studies were identified that examined associations between preterm birth and exposure to five categories of environmental toxicants, including persistent organic pollutants, drinking-water contaminants, atmospheric pollutants, metals and metalloids, and other environmental contaminants. Individual studies were summarized and specific suggestions were made for future work in regard to exposure and outcome assessment methods as well as study design, with the recommendation of focusing on potential mediating toxicological mechanisms. In conclusion, no consistent evidence was found for positive associations between individual chemical exposures and preterm birth. By identifying limitations and addressing the gaps that may have impeded the ability to identify true associations thus far, this review can guide future epidemiologic studies of environmental exposures and preterm birth.
[Ferguson KK, O'Neill MS, Meeker JD. 2013. J Toxicol Environ Health B Crit Rev. 16(2):69-113]
- Environmental exposure to pyrethroids and sperm sex chromosome disomy: a cross-sectional study.
This study investigated whether environmental exposure to pyrethroids was associated with altered frequency of sperm sex chromosome disomy in adult men. A sample of 75 subjects recruited through a Massachusetts infertility clinic provided urine and semen samples. Individual exposures were measured as urinary concentrations of three pyrethroid metabolites ((3-phenoxybenzoic acid (3PBA), cis- and trans- 3-(2,2-Dichlorovinyl)-1-methylcyclopropane-1,2-dicarboxylic acid (CDCCA and TDCCA)). Multiprobe fluorescence in situ hybridization for chromosomes X, Y, and 18 was used to determine XX, YY, XY, 1818, and total sex chromosome disomy in sperm nuclei. Poisson regression analysis was used to examine the association between aneuploidy rates and pyrethroid metabolites while adjusting for covariates. Between 25-56% of the sample were above the limit of detection (LOD) for the pyrethroid metabolites. All sex chromosome disomies were increased by 7-30% when comparing men with CDCCA and TDCCA levels above the LOD to those below the LOD. For 3PBA, compared to those below the LOD, those above the LOD had YY18 disomy rates 1.28 times higher whereas a reduced rate was seen for XY18 and total disomy, and no association was seen for XX18 and 1818. Findings suggest that urinary concentrations of CDCCA and TDCCA above the LOD were associated with increased rates of aneuploidy. However the findings for 3BPA were not consistent.
[Young HA, Meeker JD, Martenies SE, et al. 2013. Environ Health. 12(1):111]
- Environmental toxins: Alarming impacts of pesticides on male fertility.
This review comprehensively summarizes the effects of more than 15 mostly used pesticides on male reproductive physiology, as recent experimental and epidemiological research have indicated their alarming impact on overall human health. Mechanisms have described that pesticide exposure damages spermatozoa, alter Sertoli or Leydig cell function, both in vitro and in vivo and thus affects semen quality. But, the literature suggests a need for more intricate research in those pesticides that are defined as mutagens or carcinogens and directly affect the hypothalamic-pituitary-gonadal axis. This literature review also proposes specific solutions to overcome these health effects.
[Sengupta P, Banerjee R. 2013. Hum Exp Toxicol.]
- Environmentally induced epigenetic transgenerational inheritance of altered Sertoli cell transcriptome and epigenome: molecular etiology of male infertility.
Environmental toxicants have been shown to induce the epigenetic transgenerational inheritance of adult onset disease, including testis disease and male infertility. The current study was designed to determine the impact of an altered sperm epigenome on the subsequent development of an adult somatic cell (Sertoli cell) that influences the onset of a specific disease (male infertility). A gestating female rat (F0 generation) was exposed to the agriculture fungicide vinclozolin during gonadal sex determination and then the subsequent F3 generation progeny used for the isolation of Sertoli cells and assessment of testis disease. As previously observed, enhanced spermatogenic cell apoptosis was observed. The Sertoli cells provide the physical and nutritional support for the spermatogenic cells. Over 400 genes were differentially expressed in the F3 generation control versus vinclozolin lineage Sertoli cells. A number of specific cellular pathways were identified to be transgenerationally altered. One of the key metabolic processes affected was pyruvate/lactate production that is directly linked to spermatogenic cell viability. The Sertoli cell epigenome was also altered with over 100 promoter differential DNA methylation regions (DMR) modified. The genomic features and overlap with the sperm DMR were investigated. Observations demonstrate that the transgenerational sperm epigenetic alterations subsequently alters the development of a specific somatic cell (Sertoli cell) epigenome and transcriptome that correlates with adult onset disease (male infertility). The environmentally induced epigenetic transgenerational inheritance of testis disease appears to be a component of the molecular etiology of male infertility.
[Guerrero-Bosagna C, Savenkova M, Haque MM, et al. 2013. PLoS One. 8(3):e59922]
- Female farmworkers' health during pregnancy: health care providers' perspectives.
Pregnant farmworkers and their fetuses are at increased risk of negative health outcomes due to environmental and occupational factors at their workplaces. Health care providers who serve farm communities can positively affect workers' health through the informed care they deliver. Yet, interviews with rural health care providers reveal limited knowledge about agricultural work or occupational and environmental health risks during pregnancy. Professional associations, government organizations, academic institutions, and practice settings must renew their efforts to ensure that environmental and occupational health education, especially as it relates to women and their children, is incorporated into academic and practice environments.
[Kelley MA, Flocks JD, Economos J, McCauley LA. 2013. Workplace Health Saf. 61(7):308-13]
- Impact of boric acid exposure at different concentrations on testicular DNA and male rats fertility.
The aim of this study was to investigate the consequences of exposure to three levels of boric acid (BA) on male rats reproduction, fertility and progeny outcome, with emphasis on testicular DNA level and quality. Adult male rats (12 weeks old) were treated orally with BA for 60 d. The results indicated that BA administration at 125 mg/kg bwt had no adverse effects on fertility, sperm characteristics or prenatal development of the impregnated females. However, at dose 250 mg, BA treatment significantly increased serum nitric oxide, testosterone, estradiol levels and testicular boron and calcium levels and also significantly reduced serum arginase activity, sperm quality and testicular DNA content with minor DNA fragmentation. The impact of BA exposure at dose 250 mg on male rats fertility was translated into increases in pre-implantation loss with a resulting decrease in the number of live fetuses/litter. In addition to the significant alteration of biochemical measurements, observed at dose 250 mg, administration of BA at 500 mg caused testicular atrophy, severe damage of spermatogenesis, spermiation failure and significant reduction of Mg and Zn testicular levels. None of the male rats, treated with 500 mg/kg bwt, could impregnate untreated females, suggesting the occurrence of definitive loss of fertility. In conclusion, BA impaired fertility, in a dose-dependant manner, by targeting the highly proliferative cells, the germ cells, through decreasing DNA synthetic rate rather than the induction of DNA damage.
[El-Dakdoky MH, Abd El-Wahab HM.2013. Toxicol Mech Methods. 23(5):360-7]
- In vitro-in vivo correlations for endocrine activity of a mixture of currently used pesticides.
Two pesticide mixtures were investigated for potential endocrine activity. Mix 3 consisted of bitertanol, propiconazole, and cypermethrin, and Mix 5 included malathion and terbuthylazine in addition to the three pesticides in Mix 3. All five single pesticides and the two mixtures were investigated for their ability to affect steroidogenesis in vitro in H295R cells. The pesticides alone and both mixtures affected steroidogenesis with both mixtures causing increase in progesterone and decrease in testosterone. For Mix 5 an increase in estradiol was seen as well, indicating increased aromatase activity. The two mixtures were also investigated in pregnant rats dosed from gestational day 7 to 21, followed by examination of dams and fetuses. Decreased estradiol and reduced placental testosterone were seen in dams exposed to Mix 5. Also a significant increase in aromatase mRNA-levels in female adrenal glands was found for Mix5. However, neither of the two mixtures showed any effects on fetal hormone levels in plasma or testis, or on anogenital distance. Overall, potential aromatase induction was found for Mix 5 both in vitro and in vivo, but not for Mix 3, an effect likely owed to terbuthylazine in Mix 5. However, the hormonal responses in vitro were only partly reflected in vivo, probably due to some toxicokinetic issues, as the pesticide levels in the amniotic fluid also were found to be negatively affected by the number of compounds present in the mixtures. Nonetheless, the H295R assay gives hints on conceivable interference with steroidogenesis, thus generating hypotheses on in vivo effects.
[Taxvig C, Hadrup N, Boberg J, et al. 2013. Toxicol Appl Pharmacol.272(3):757-66]
- Late life effects on rat reproductive system after developmental exposure to mixtures of endocrine disrupters
This study examined late life effects of perinatal exposure of rats to a mixture of endocrine disrupting contaminants. Four groups of 14 time-mated Wistar rats were exposed by gavage from gestation day 7 to pup day 22 to a mixture of 13 anti-androgenic and estrogenic chemicals including phthalates, pesticides, UV-filters, bisphenol A, parabens and the drug paracetamol.Onset of puberty and estrous cyclicity at 9 and 12 months of age was assessed. Significantly fewer females showed regular estrus cyclicity at 12 months of age in the 2 exposure groups compared to controls. In 19 months old male offspring, epididymal sperm counts were lower than controls and in ventral prostate, an over-representation of findings related to hyperplasia was observed in exposed groups compared to controls particularly in the group dosed with anti-androgens. A higher incidence of pituitary adenoma at 19 months of age was found in males and females in the high dose group. Developmental exposure of rats to the highest dose of a human relevant mixture of endocrine disrupters induced adverse effects late in life manifested as earlier female reproductive senescence, reduced sperm counts, higher score for prostate atypical hyperplasia and higher incidence of pituitary tumors. These delayed effects highlight the need for further studies on the role of endocrine disrupters in hormone-related disorders in aging humans.
[Isling LK, Boberg J, Jacobsen PR, et al. 2013. Reproduction. doi: 10.1530/REP-13-0448]
- Male pubertal development: are endocrine-disrupting compounds shifting the norms?
Endocrine-disrupting compounds (EDCs) are synthetic or natural compounds that interfere with endogenous endocrine action. In humans, a growing number of epidemiological studies report an association with altered pubertal timing and progression. This review focuses on the small number of studies performed in males that report an association of polychlorinated biphenyls with earlier sexual maturity rating and confirm subtle effects of lead, dioxins, and endosulfan on delaying pubertal onset and progression in boys. Recent studies have also demonstrated that EDC exposure may affect pubertal testosterone production without having a noticeable effect on sexual maturity rating. A limitation to understand the effects of EDCs in humans is the potential for confounding due to the long temporal lag from early-life exposures to adult outcomes. The complex interplay of multiple environmental exposures over time also complicates the interpretation of human studies. These studies have identified critical windows of vulnerability during development when exposures to EDCs alter critical pathways and affect postnatal reproductive health. Contemporaneous exposures can also disrupt the hypothalamic-pituitary-gonadal axis. This paper reviews the normal process of puberty in males and summarize human data that suggest potential perturbations in pubertal onset and tempo with early-life exposures to EDCs.
[Zawatski W, Lee MM. 2013. J Endocrinol. 218(2):R1-12]
- Metabolomics tools for describing complex pesticide exposure in pregnant women in Brittany (France).
This study aims to answer to following questions: What is the influence of exposures to multiple pesticides on the metabolome? What mechanistic pathways could be involved in the metabolic changes observed? Based on the PELAGIE cohort (Brittany, France), 83 pregnant women who provided a urine sample in early pregnancy, were classified in 3 groups according to the surface of land dedicated to agricultural cereal activities in their town of residence. The 3 groups of exposure were correctly separated with a PLS-DA model after implementing an orthogonal signal correction with pareto standardizations (R2 = 90.7% and Q2 = 0.53). After adjusting for maternal age, parity, body mass index and smoking habits, the most statistically significant changes were observed for glycine, threonine, lactate and glycerophosphocholine (upward trend), and for citrate (downward trend). This work suggests that an exposure to complex pesticide mixtures induces modifications of metabolic fingerprints. It can be hypothesized from identified discriminating metabolites that the pesticide mixtures could increase oxidative stress and disturb energy metabolism.
[Bonvallot N, Tremblay-Franco M, Chevrier C. et al. 2013. PLoS One. 8(5):e64433]
- Occupational exposure to organophosphate and carbamate pesticides affects sperm chromatin integrity and reproductive hormone levels among Venezuelan farm workers.
Several reports suggest that chronic pesticide exposure may affect semen quality and male fertility in humans. The objective of this study was to evaluate the association between occupational exposure to organophosphate (OP) and carbamate (CB) pesticides and semen quality, as well as levels of reproductive and thyroid hormones of Venezuelan farm workers. Thirty-five healthy men (unexposed group) and 64 male agricultural workers (exposed group) were recruited for clinical evaluation of fertility status. Fresh semen samples were evaluated for sperm quality and analyzed for DNA fragmentation index (DFI) by flow cytometry. Pesticide exposure was assessed by measuring erythrocyte acetylcholinesterase (AChE) and plasma butyrylcholinesterase (BuChE) with a Test-mate ChE field kit. Serum levels of total testosterone (Tt), follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), thyroid stimulating hormone (TSH) and free thyroxine (FT4) were analyzed using enzyme immunoassay kits. Evidence of pesticide exposure was found in 87.5% of farmers based on AChE and BuChE inhibition. Significant increments were observed in sperm DFI with significant decreases in some semen parameters. DFI was negatively correlated with BuChE, sperm concentration, morphology and vitality in these workers. The levels of Tt, PRL, FT4 and TSH appeared to be normal; however, there was a tendency for increased LH and FSH levels in exposed workers. Results confirm the potential impact of chronic occupational exposure to OP/CB pesticides on male reproductive function, which may cause damage to sperm chromatin, decrease semen quality and produce alterations in reproductive hormones, leading to adverse reproductive health outcomes.
[Miranda-Contreras L, Gómez-Pérez R, Rojas G, et al. 2013. J Occup Health. 55(3):195-203]
- Organochlorine compound levels in fertile and infertile women from Rio de Janeiro, Brazil.
The aim of the study was quantify organochlorine compounds in women seeking infertility treatment and in spontaneously pregnant ones. From the pesticides studied, pp'DDE was detected in 100% of infertile women, at higher mean levels than in pregnant women, without correlation with the etiology of infertility. Levels of the polychlorinated biphenyls (PCBs) were low, with positive samples in 100% in the infertile women for PCBs 138, 153, 180, while in pregnant women, they were 85.7% for congeners 138 and 153. Only PCB180 showed significance, with frequency of 71.4%. The risk factors for female infertility were: age, consumption of untreated water and of canned foods. Exposure to the most prevalent organochlorine compounds described in literature was confirmed in the study, indicating that pp'DDE may adversely influence female fertility.
[Bastos AM, de Souza Mdo C, de Almeida Filho GL, et al. 2013. Arq Bras Endocrinol Metabol.57(5):346-53]
- Organochlorine Pesticides and Risk of Endometriosis: Findings from a Population-Based Case-Control Study.
Endometriosis is considered an estrogen-dependent disease. Persistent environmental chemicals that exhibit hormonal properties, such as organochlorine pesticides (OCPs), may affect endometriosis risk. Authors investigated endometriosis risk in relation to environmental exposure to OCPs. They conducted the present analyses using data from the Women's Risk of Endometriosis (WREN) study, a population-based case-control study of endometriosis conducted among 18- to 49-year-old female enrollees of a large health care system in western Washington State. OCP concentrations were measured in sera from surgically confirmed endometriosis cases first diagnosed between 1996 and 2001 and from population-based controls. Data suggested increased endometriosis risk associated with serum concentrations of β-hexachlorocyclohexane (HCH) and mirex. The association between serum β-HCH concentrations and endometriosis was stronger in analyses restricting cases to those with ovarian endometriosis.
[Upson K, De Roos AJ, Thompson ML,et al. 2013. Environ Health Perspect. 11-12;121(11-12):1319-1324]
- Paternal fenvalerate exposure influences reproductive functions in the offspring.
The aim of the present study was to elucidate whether adverse effects on male reproductive system are passed from exposed male mice to their offspring. Adult male mice received Fen (10 mg/kg) daily for 30 days and mated with untreated females to produce offspring. Fenvalerate significantly changed the methylation status of angiotensin I-converting enzyme (Ace), forkhead box O3 (Foxo3a), huntingtin-associated protein 1 (Hap1), nuclear receptor subfamily 3 (Nr3c2), promyelocytic leukemia (Pml), and Prostaglandin F2 receptor negative regulator (Ptgfrn) genes in paternal mice sperm genomic DNA. Further, Fen significantly increased sperm abnormalities; serum testosterone and estradiol-17ß level in adult male (F0) and their male offspring (F1). Further, paternal Fen treatment significantly increased the length of estrous cycle, serum estradiol-17ß concentration in estrus, and progesterone levels in diestrus in female offspring (F1). These findings suggest that adverse effects of paternal Fen exposure on reproductive functions can be seen not only in treated males (F0) but also in their offsprings.
[Xia D, Parvizi N, Zhou Y, et al. 2013. Reprod Sci. 20(11):1308-15.]
- Pre- and postnatal toxicity of diazinon induces disruption of spermatogenetic cell line evidenced by increased testicular marker enzymes activities in rat offspring.
The objective of this study was to study the possible reproductive adverse effects of the diazinon on rat offspring exposed in utero and during lactation. Dams were gavaged daily before mating, during mating, and during pregnancy and lactation in separate groups. Reproductive outcome data of dams were examined. Body weight, testis weight, testicular marker enzyme activities (alkaline phosphatase, acid phosphatase, lactate dehydrogenase, and glucose-6-phosphate dehydrogenase), qualitative and quantitative testicular and epididymal histology, and immunohistochemisty for 3-β-hydroxysteroid dehydrogenase (HSD) were examined in male offspring at puberty and adulthood. The 30-mg/kg dose induced significant adverse effects at both puberty and adulthood in offspring. At puberty the male offspring showed a decrease in testicular weight, degenerative changes, and 3-β-HSD. At adulthood, there was a decrease in testicular weight and 3-β-HSD with an increase in the levels of testicular marker enzyme. Most of the adverse effects were irreversible and were evident at both puberty and adulthood in offspring, although a few parameters reverted back to the normal growth pattern. Hence, diazinon is a reproductive toxicant in male offspring, which caused significant damage to the testes when exposed during prenatal and postnatal life.
[Jayachandra S, D'Souza UJ. 2013. J Environ Pathol Toxicol Oncol.32(1):73-90]
- Prenatal exposure to the pesticide DDT and hypertension diagnosed in women before age 50: a longitudinal birth cohort study.
Elevated levels of the pesticide DDT (dichlorodiphenyltrichloroethane) have been positively associated with blood pressure and hypertension in studies among adults. Accumulating epidemiologic and toxicologic evidence suggests that hypertension during adulthood may also be affected by earlier life and possibly the prenatal environment. Study assessed whether prenatal exposure to the pesticide DDT increases risk of adult hypertension. Authors examined concentrations of DDT (p,p´- and o,p´-) and its metabolite p,p´-DDE (dichlorodiphenyldichloroethylene) in prenatal serum samples from a subset of women who had participated in the prospective Child Health and Development Studies birth cohort in the San Francisco Bay area while they were pregnant between 1959 and 1967. Authors surveyed daughters 39-47 years of age. Prenatal p,p´-DDT exposure was associated with hypertension. These associations between p,p´-DDT and hypertension were robust to adjustment for independent hypertension risk factors as well as sensitivity analyses. These findings suggest that the association between DDT exposure and hypertension may have its origins early in development.
[La Merrill M, Cirillo PM, Terry MB, et al. 2013. Environ Health Perspect. 121(5):594-9]
- Reproductive effects of two neonicotinoid insecticides on mouse sperm function and early embryonic development in vitro.
Acetamiprid (ACE) and imidacloprid (IMI) are two major members in the family of neonicotinoid pesticides, which are synthesized with a higher selectivity to insects. The present study determined and compared in vitro effects of ACE, IMI and nicotine on mammalian reproduction by using an integrated testing strategy for reproductive toxicology, which covered sperm quality, sperm penetration into oocytes and preimplantation embryonic development. Direct chemical exposure on spermatozoa during capacitation was performed, and in vitro fertilization (IVF) process, zygotes and 2-cell embryos were respectively incubated with chemical-supplemented medium until blastocyst formation to evaluate the reproductive toxicity of these chemicals and monitor the stages mainly affected. Generally, treatment of 500 µM or 5 mM chemicals for 30 min did not change sperm motility and DNA integrity significantly but the fertilization ability in in-vitro fertilization (IVF) process, indicating that IVF process could detect and distinguish subtle effect of spermatozoa exposed to different chemicals. Culture experiment in the presence of chemicals in medium showed that fertilization process and zygotes are adversely affected by direct exposure of chemicals, in an order of nicotine>IMI>ACE, whereas developmental progression of 2-cell stage embryos was similar to controls. These findings unveiled the hazardous effects of neonicotinoid pesticides exposure on mammalian sperm fertilization ability as well as embryonic development, raising the concerns that neonicotinoid pesticides may pose reproductive risks on human reproductive health, especially in professional populations.
[Gu YH, Li Y, Huang XF, et al. 2013. PLoS One. 8(7):e70112]
- Residential proximity to methyl bromide use and birth outcomes in an agricultural population in California.
Methyl bromide, a fungicide often used in strawberry cultivation, is of concern for residents who live near agricultural applications because of its toxicity and potential for drift. Little is known about the effects of methyl bromide exposure during pregnancy. The study investigated the relationship between residential proximity to methyl bromide use and birth outcomes. Participants were from the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) study. Using data from the California Pesticide Use Reporting system, authors employed a geographic information system to estimate the amount of methyl bromide applied within 5 km of a woman's residence during pregnancy. Multiple linear regression models were used to estimate associations between trimester-specific proximity to use and birth weight, length, head circumference, and gestational age. High methyl bromide use (vs. no use) within 5 km of the home during the second trimester was negatively associated with birth weight, birth length, and head circumference. These outcomes were also associated with moderate methyl bromide use during the second trimester. Negative associations with fetal growth parameters were stronger when larger (5 km and 8 km) versus smaller (1 km and 3 km) buffer zones were used to estimate exposure.
[Gemmill A, Gunier RB, Bradman A, et al. 2013. Environ Health Perspect. 121(6):737-43]
- Roundup disrupts male reproductive functions by triggering calcium-mediated cell death in rat testis and Sertoli cells.
The present results show that acute Roundup exposure at low doses (36ppm, 0.036g/L) for 30min induces oxidative stress and activates multiple stress-response pathways leading to Sertoli cell death in prepubertal rat testis. The pesticide increased intracellular Ca(2+) concentration by opening L-type voltage-dependent Ca(2+) channels as well as endoplasmic reticulum IP3 and ryanodine receptors, leading to Ca(2+) overload within the cells, which set off oxidative stress and necrotic cell death. Similarly, 30min incubation of testis with glyphosate alone (36ppm) also increased (45)Ca(2+) uptake. These events were prevented by the antioxidants Trolox and ascorbic acid. Activated protein kinase C, phosphatidylinositol 3-kinase, and the mitogen-activated protein kinases such as ERK1/2 and p38MAPK play a role in eliciting Ca(2+) influx and cell death. Roundup decreased the levels of reduced glutathione (GSH) and increased the amounts of thiobarbituric acid-reactive species (TBARS) and protein carbonyls. Also, exposure to glyphosate-Roundup stimulated the activity of glutathione peroxidase, glutathione reductase, glutathione S-transferase, γ-glutamyltransferase, catalase, superoxide dismutase, and glucose-6-phosphate dehydrogenase, supporting downregulated GSH levels. Glyphosate has been described as an endocrine disruptor affecting the male reproductive system; however, the molecular basis of its toxicity remains to be clarified. We propose that Roundup toxicity, implicated in Ca(2+) overload, cell signaling misregulation, stress response of the endoplasmic reticulum, and/or depleted antioxidant defenses, could contribute to Sertoli cell disruption in spermatogenesis that could have an impact on male fertility.
[de Liz Oliveira Cavalli VL, Cattani D, Heinz Rieg CE, et al. 2013. Free Radic Biol Med. 65:335-46]
- The effects of pyridaben pesticide on the histomorphometric, hormonal alternations and reproductive functions of BALB/c mice.
This study was designed to elucidate how pyridaben can effects the histomorphometric, hormonal alternations and reproductive functions of BALB/c mice. 80 adult and apparently healthy male BALB/c mice were received the toxin at doses of 53 mg/kg. BW, and 212 mg/kg. BW, respectively.The levels of FSH, LH and testosterone were significantly decreased on the dose and time dependant means. The levels of the ROS and NOS were significantly increased in all test groups. The percent body weight gains significantly reduced, whereas weights significantly increased in test groups in a dose and time dependant manner. The histomorphometric and stereologic findings, including diameters of somniferous tubules, thickness of somniferous tubules epithelium, the leydig's cell distribution, TDI, SI, RI revealed that, all these parameters are also significantly reduces in test groups in a dose and time dependant manner. Study concludes that pyridaben causes histomorphometric and stereologic changes in testis, as well as hormonal and reproductive functional alternations in BALB/c mice.
[Ebadi Manas G, Hasanzadeh S, Parivar K. 2013. Iran J Basic Med Sci.16(10):1055-64.]
- Adverse effects on sexual development in rat offspring after low dose exposure to a mixture of endocrine-disrupting pesticides.
The present study investigated whether a mixture of low doses of five environmentally relevant endocrine disrupting pesticides, epoxiconazole, mancozeb, prochloraz, tebuconazole and procymidone, would cause adverse developmental toxicity effects in rats. In rat dams, a significant increase in gestation length was seen, while in male offspring increased nipple retention and increased incidence and severity of genital malformations were observed. Severe mixture effects on gestation length, nipple retention and genital malformations were seen at dose levels where the individual pesticides caused no or smaller effects when given alone. Generally, the mixture effect predictions based on dose-additivity were in good agreement with the observed effects. The results indicate that there is a need for modification of risk assessment procedures for pesticides, in order to take account of the mixture effects and cumulative intake, because of the potentially serious impact of mixed exposure on development and reproduction in humans.
[Hass U, Boberg J, Christiansen S, Jacobsen PR, et al. 2012. Reprod Toxicol.34(2):261-74]
- Characterization of endocrine-disrupting chemicals based on hormonal balance disruption in male and female adult rats.
Reproductive functions are controlled by a finely tuned balance between estrogens and androgens. To further characterize the gonadal pathways leading to hormonal balance disruption by atrazine, vinclozolin, methoxychlor, and bisphenol A in rat, study investigated their effects in male and female young adult animals. Specifically, reproductive tract alterations, sex hormone balance in serum and gonads, tissue dosimetry, and mRNA expression were assessed. Study observed different aromatase regulation profiles between animals with similar estrogen-to-androgen ratios but with different chemical treatments. For example, increased estrogen-to-androgen ratios in atrazine-treated females could be partly linked to aromatase upregulation, while in methoxychlor- and bisphenol A-treated females, peripheral mechanisms such as conjugation/deconjugation processes might be more likely to elevate estrogen levels. In vinclozolin-treated animals, the decreased estrogen-to-androgen ratios reported might be due to an increase of peripheral (adrenal) steroidogenesis. Thus, measurement of many endpoints is necessary for good risk assessment.
[Quignot N, Arnaud M, Robidel F, Lecomte A, et al. 2012. Reprod Toxicol. 33(3):339-52.]
- Dioxin (TCDD) induces epigenetic transgenerational inheritance of adult onset disease and sperm epimutations.
The current study examined the ability of dioxin (2,3,7,8-tetrachlorodibenzo[p]dioxin, TCDD) to promote epigenetic transgenerational inheritance of disease and DNA methylation epimutations in sperm. Gestating F0 generation females were exposed to dioxin during fetal day 8 to 14 and adult-onset disease was evaluated in F1 and F3 generation rats. The incidences of total disease and multiple disease increased in F1 and F3 generations. Prostate disease, ovarian primordial follicle loss and polycystic ovary disease were increased in F1 generation dioxin lineage. Kidney disease in males, pubertal abnormalities in females, ovarian primordial follicle loss and polycystic ovary disease were increased in F3 generation dioxin lineage animals. Analysis of the F3 generation sperm epigenome identified 50 differentially DNA methylated regions (DMR) in gene promoters. These DMR provide potential epigenetic biomarkers for transgenerational disease and ancestral environmental exposures. Observations demonstrate dioxin exposure of a gestating female promotes epigenetic transgenerational inheritance of adult onset disease and sperm epimutations.
[Manikkam M, Tracey R, Guerrero-Bosagna C, Skinner MK. 2012. PLoS One.7(9):e46249]
- Evidence for diazinon-mediated inhibition of cis-permethrin metabolism and its effects on reproductive toxicity in adult male mice.
The potential toxicity resulting from combinatorial effects of organophosphorus and pyrethroid insecticides are not completely known. We evaluated male reproductive toxicity in mice co-exposed to diazinon and cis-permethrin. Nine-week-old male mice were exposed to diazinon or cis-permethrin alone or in combination, or vehicle (corn oil), for 6 weeks. Diazinon and the diazinon-permethrin mixture inhibited plasma and liver carboxylesterase activities. In the mixture group, urinary excretion of cis-permethrin metabolite 3-phenoxybenzoic acid decreased along with increased plasma and testicular concentrations of cis-permethrin, while excretion of diazinon metabolites, diethylphosphate and diethylthiophosphate, did not change, versus mice exposed to each chemical alone, which suggested that inhibition of carboxylesterase decreased the metabolic capacity to cis-permethrin. Though the co-exposure decreased testosterone biosynthesis, increased degenerate germ cells in seminiferous tubule and sperm morphological abnormalities versus controls more clearly than exposure to cis-permethrin alone, the expected potentiation of toxicity was not evident.
[Wang D, Kamijima M, Okamura A, et al. 2012. Reprod Toxicol. 34(4):489-97]
- Glyphosate impairs male offspring reproductive development by disrupting gonadotropin expression.
Glyphosate has been shown to alter aromatase activity and decrease serum testosterone concentrations. The aim of this study was to investigate the effect of gestational maternal glyphosate exposure on the reproductive development of male offspring. Sixty-day-old male rat offspring were evaluated for sexual behavior and partner preference; serum testosterone concentrations, estradiol, FSH and LH; the mRNA and protein content of LH and FSH; sperm production and the morphology of the seminiferous epithelium; and the weight of the testes, epididymis and seminal vesicles. The growth, the weight and age at puberty of the animals were also recorded to evaluate the effect of the treatment. The most important findings were increases in sexual partner preference scores and the latency time to the first mount; testosterone and estradiol serum concentrations; the mRNA expression and protein content in the pituitary gland and the serum concentration of LH; sperm production and reserves; and the height of the germinal epithelium of seminiferous tubules. An early onset of puberty but no effect on the body growth in these animals was also observed. These results suggest that maternal exposure to glyphosate disturbed the masculinization process and promoted behavioral changes and histological and endocrine problems in reproductive parameters. These changes associated with the hypersecretion of androgens increased gonadal activity and sperm production.
[Romano MA, Romano RM, Santos LD, et al. 2012. Arch Toxicol. 86(4):663-73]
- Pesticide and insect repellent mixture (permethrin and DEET) induces epigenetic transgenerational inheritance of disease and sperm epimutations.
The current study was designed to determine if a "pesticide mixture" (pesticide permethrin and insect repellent N,N-diethyl-meta-toluamide, DEET) promotes epigenetic transgenerational inheritance of disease and associated DNA methylation epimutations in sperm. Gestating F0 generation female rats were exposed during fetal gonadal sex determination and the incidence of disease evaluated in F1 and F3 generations. There were significant increases in the incidence of total diseases in animals from pesticide lineage F1 and F3 generation animals. Pubertal abnormalities, testis disease, and ovarian disease (primordial follicle loss and polycystic ovarian disease) were increased in F3 generation animals. Analysis of the pesticide lineage F3 generation sperm epigenome identified 363 differential DNA methylation regions (DMR) termed epimutations. Observations demonstrate that a pesticide mixture (permethrin and DEET) can promote epigenetic transgenerational inheritance of adult onset disease and potential sperm epigenetic biomarkers for ancestral environmental exposures.
[Manikkam M, Tracey R, Guerrero-Bosagna C, Skinner MK. 2012. Reprod Toxicol. 34(4):708-19]
- Transgenerational actions of environmental compounds on reproductive disease and identification of epigenetic biomarkers of ancestral exposures.
Environmental factors during fetal development can induce a permanent epigenetic change in the germ line (sperm) that then transmits epigenetic transgenerational inheritance of adult-onset disease in the absence of any subsequent exposure. The epigenetic transgenerational actions of various environmental compounds and relevant mixtures were investigated with the use of a pesticide mixture (permethrin and insect repellant DEET), a plastic mixture (bisphenol A and phthalates), dioxin (TCDD) and a hydrocarbon mixture (jet fuel, JP8). The effects on the F1, F2 and F3 generations pubertal onset and gonadal function were assessed. The plastics, dioxin and jet fuel were found to promote early-onset female puberty transgenerationally (F3 generation). Spermatogenic cell apoptosis was affected transgenerationally. Ovarian primordial follicle pool size was significantly decreased with all treatments transgenerationally. Differential DNA methylation of the F3 generation sperm promoter epigenome was examined. Differential DNA methylation regions (DMR) were identified in the sperm of all exposure lineage males and found to be consistent within a specific exposure lineage, but different between the exposures. Exposure-specific epigenetic biomarkers were identified that may allow for the assessment of ancestral environmental exposures associated with adult onset disease.
[Manikkam M, Guerrero-Bosagna C, et al. 2012.PLoS One. 7(2):e31901.]
- Two-generation reproduction toxicity study in rats with methoxychlor.
A two-generation reproduction toxicity study was conducted in rats with a reference estrogenic pesticide, methoxychlor, to validate the sensitivity and competency of current guidelines recommended by the United States Environmental Protection Agency; Japanese Ministry of Agriculture, Forestry and Fisheries; and Organisation for Economic Co-operation and Development for predicting reproductive toxicity of the test compound based on estrogenic endocrine disrupting effects. Both sexes of SD rats were exposed to methoxychlor in the diet at concentrations of 0, 10, 500 and 1500 ppm for two successive generations. The present study has successfully detected estrogenic activities and reproductive toxicities of methoxychlor, as well as its systemic toxicity. Body weights, body weight gains and food consumption of both sexes of animals were suppressed significantly in the 500 and 1500 ppm groups. Typical reproductive toxicities observed in females of these groups included, but were not limited to, prolonged estrous cycle, reduced fertility, decreased numbers of implantation sites and newborns, decreased ovary weights and/or increased incidences of cystic ovary. Uterine weights of weanlings increased significantly in these groups, suggesting that the sensitivity of this parameter for predicting estrogenic ability of the test compound is comparable to that of the uterotrophic assay. Reproductive toxicities of methoxychlor seemed less potent in males than in females. Methoxychlor delayed preputial separation and significantly reduced sperm counts and reproductive organ weights of males of the 500 and/or 1500 ppm groups; however, most males that failed to impregnate females in the same group showed normal fertility when they were re-mated with untreated females. Neither systemic nor reproductive toxicities appeared in the 10 ppm group.
[Aoyama H, Hojo H, Takahashi KL, et al. 2012. Congenit Anom (Kyoto). 52(1):28-41]
- Dioxin Exposure and Age of Pubertal Onset among Russian Boys
Animal data demonstrate associations of dioxin, furan, and polychlorinated biphenyl (PCB) exposures with altered male gonadal maturation. It is unclear whether these associations apply to human populations. We investigated the association of dioxins, furans, PCBs, and corresponding toxic equivalent (TEQ) concentrations with pubertal onset among boys in a dioxin-contaminated region. Between 2003 and 2005, 499 boys 8–9 years of age were enrolled in a longitudinal study in Chapaevsk, Russia. Pubertal onset [stage 2 or higher for genitalia (G2+) or testicular volume (TV) > 3 mL] was assessed annually between ages 8 and 12 years. Serum levels at enrollment were analyzed by the Centers for Disease Control and Prevention, Atlanta, Georgia, USA. We used Cox proportional hazards models to assess age at pubertal onset as a function of exposure adjusted for potential confounders. We conducted sensitivity analyses excluding boys with pubertal onset at enrollment. The median (range) total serum TEQ concentration was 21 (4–175) pg/g lipid, approximately three times higher than values in European children. At enrollment, boys were generally healthy and normal weight (mean body mass index, 15.9 kg/m2), with 30% having entered puberty by G2+ and 14% by TV criteria. Higher dioxin TEQs were associated with later pubertal onset by TV (hazard ratio = 0.68, 95% confidence interval, 0.49–0.95 for the highest compared with the lowest quartile). Similar associations were observed for 2,3,7,8-tetrachlorodibenzo-p-dioxin and dioxin concentrations for TV but not G2+. Results were robust to sensitivity analyses. Findings support an association of higher peripubertal serum dioxin TEQs and concentrations with later male pubertal onset reflected in delayed testicular maturation.
[Korrick, S.A., Lee, M., Williams, P., et al. 2011. Environ Health Perspect. 119 (9):1339–1344.]
- Internal exposure to pollutants and sexual maturation in Flemish adolescents
Sexual maturation of adolescents (aged 14-15 years) was studied in relation to internal exposure to pollutants. Serum levels of pollutants and sex hormones were measured in 1679 participants selected as a random sample of the adolescents residing in the study areas. Data on sexual development were obtained from the medical school examination files. Self-assessment questionnaires provided information on health, use of medication and lifestyle factors. In boys, serum levels of hexachlorobenzene (HCB), p,p'-DDE and polychlorinated biphenyls (sum of marker PCB138, 153 and 180) were significantly and positively associated with pubertal staging (pubic hair and genital development). Higher levels of serum HCB and blood lead were associated with, respectively, a lower and a higher risk of gynecomastia. In girls, significant and negative associations were detected between blood lead and pubic hair development; higher exposure to PCBs was significantly associated with a delay in timing of menarche. Further understanding of toxic mode of action and sensitive windows of exposure is needed to explain the current findings.
[Den Hond, E., Dhooge, W., Bruckers,L., Schoeters,G., et al. 2011.J Expo Sci Environ Epidemiol.21(3): 224–233.]
- Synergistic effect of dichlorvos, dimethoate and malathion mixture on reproduction toxicity in male mice
To evaluate the reproduction toxicity of the mixture composed of dichlorvos, dimethoate and malathion synergistic effect on male mice, and further explore its possible mechanisms.The 105 male mice were divided into 7 groups, including control. The oral gavage was given for successive 35 days, and the mice were sacrificed on the 36(th) day. The levels of sexual hormone were measured, including testosterone (T), follicle stimulating hormone (FSH), luteinizing hormone (LH) and estradiol (E(2)). Pathological changes of testicle and epididymis were observed by morphology, pathology and electron microscope. After 14 days exposure, the body weights of the mice were lower in the mix-high dose group (than those in control group. After 28 days exposure, the body weights of the mice were also lower in the mix-medium dose group. The sperm counts and sperm motility decreased significantly as the toxic concentration arised. Comparing to control group, the spermatozoa count and sperm motility had decreased in mix-medium and mix-high dose groups, and the sperm abnormality rates were higher in mix-medium and mix-high groups. Compared to those in control group, the serum level of FSH, E(2) in mix-medium and mix-high dose group increased, while the level of LH and T decreased. The morphological and ultramicrostructure results of testicle and epididymis indicated that the mature sperm numbers were decreased, and the cacoplastic sperm head and the tail of spermatozoon were observed in mix-high dose groups. Thus, the dichlorvos, dimethoate and malathion mixture had synergistic reproductive toxicity to the testicle and epididymis structure and function, and thus leading to the process of generation cell cytopoiesis abnormalities, simultaneously the hypothalamus-pituitary-gonad axis were also affected and thus resulted in parasecretion.
[Yu Y, Yang AM, Zhang JH et al. 2011. Chinese Journal of Preventive Medicine. 45(9):810-4]
- The effects of prenatal exposure to atrazine on pubertal and postnatal reproductive indices in the female rat.
Atrazine (ATR) is an herbicide that exerts negative reproductive effects. Study examined the effects of vehicle or ATR (1, 5, 20 and 100mg/kg-d), administered to Sprague-Dawley rats on gestational days 14-21, once daily or divided into two doses per day, on female offspring reproductive indices. Offspring body weights at birth were reduced and mortality increased in the 100mg/kg-d group shortly after birth; by PND 21 there were no significant effects. Vaginal opening was delayed in this group, indicating delayed puberty. No significant differences in mammary gland development were apparent at PND 45, or estrous cyclicity through PND 272. There were no differences between dosing regimens. Lower ATR doses showed few effects in females prenatally exposed to ATR, while the high dose reduced offspring body weight and delayed vaginal opening. Nonetheless, it is unlikely that environmental exposure comparable to the high dose would be encountered.
[Davis LK, Murr AS, Best DS, Fraites MJ, et al. 2011. Reprod Toxicol. 32(1):43-51]
- Widely Used Pesticides with Previously Unknown Endocrine Activity Revealed as in Vitro Anti-Androgens
Researchers screened pesticides using in-vitro assays, which use human cells to check whether the pesticides activate or inhibit hormone receptors in cells that turn genes on and off. ScientistsThirty out of 37 pesticides tested by the researchers altered male hormones, including 16 that had no known hormonal activity until now. There was some previous evidence for the other 14 . The most potent in terms of blocking androgens was the insecticide fenitrothion, an organophosphate insecticide. Others with hormonal activity include fludioxonil, fenhexamid, dimethomorph and imazalil, which are all fungicides. Due to estimated anti-androgenic potency, current use, estimated exposure, and lack of previous data, authors strongly recommend that dimethomorph, fludioxonil, fenhexamid, imazalil, ortho-phenylphenol and pirimiphos-methyl be tested for anti-androgenic effects in vivo.
[Orton F, Rosivatz E, Scholze M, Kortenkamp A 2011. Environ Health Perspect. doi:10.1289/ehp.1002895]
- Effects of prenatal exposure to a low dose atrazine metabolite mixture on pubertal timing and prostate development of male Long-Evans rats
The present study examines the postnatal reproductive development of male rats following prenatal exposure to an atrazine metabolite mixture (AMM) consisting of the herbicide atrazine and its environmental metabolites diaminochlorotriazine, hydroxyatrazine, deethylatrazine, and deisopropylatrazine. Pregnant Long-Evans rats were treated by gavage with 0.09, 0.87, or 8.73 mg AMM/kg body weight (BW), vehicle, or 100 mg ATR/kg BW positive control, on gestation days 15–19. Preputial separation was significantly delayed in 0.87 mg and 8.73 mg AMM-exposed males. AMM-exposed males demonstrated a significant treatment-related increase in incidence and severity of inflammation in the prostate on postnatal day (PND) 120. A dose-dependent increase in epididymal fat masses and prostate foci were grossly visible in AMM-exposed offspring. These results indicate that a short, late prenatal exposure to mixture of chlorotriazine metabolites can cause chronic prostatitis in male LE rats. The mode of action for these effects is presently unclear.
[Stanko JP, et al. 2010. Reprod Toxicol. Epub ahead of print. DOI:10.1016/j.reprotox.2010.07.006]
- Maternal pesticide use and birth weight in the Agricultural Health Study
Studies examining the association between maternal pesticide exposure and low birth weight yield conflicting results. The authors examined the association between maternal pesticide use and birth weight among women in the Agricultural Health Study, a large study of pesticide applicators and their spouses in Iowa and North Carolina. The authors evaluated self-reported pesticide use of 27 individual pesticides in relation to birth weight among 2246 farm women whose most recent singleton birth occurred within 5 years of enrollment (1993-1997). First-trimester pesticide-related tasks were not associated with birth weight. Ever use of the pesticide carbaryl was associated with decreased birth weight. This study thus provides limited evidence about pesticide use as a modulator of birth weight. Overall, the authors observed no associations between birth weight and pesticide-related activities during early pregnancy; however, the authors have no data on temporal specificity of individual pesticide exposures prior to or during pregnancy and therefore cannot draw conclusions related to these exposure windows. Given the widespread exposure to pesticide products, additional evaluation of maternal pregnancy exposures at specific time windows and subsequent birth outcomes is warranted.
[Sathyanarayana S., O. Basso, C.J. Karr, P., et al. 2010. J Agromedicine.15 (2): 127-36]
- Fourth National Report on Human Exposure to Environmental Chemicals
Report found more than 90 percent of males in the U.S. population had urine samples with detectable levels of metabolites of chlorpyrifos (TCPY). Over 75% of U.S. males had detectable levels of metabolites of naphthalene (1N). Chlorpyrifos is a known cholinesterase inhibitor, which the researchers believe may affect the release of luteinizing hormone (LH), the hormone that triggers testosterone secretion from the Leydig cells.
[Centers for Disease Control and Prevention. 2009. Atlanta, GA.]
- Profiling the Reproductive Toxicity of Chemicals from Multigeneration Studies in the Toxicity Reference Database
Multigeneration reproduction studies are used to characterize parental and offspring systemic toxicity, as well as reproductive toxicity of pesticides, industrial chemicals and pharmaceuticals. Results from 329 multigeneration studies on 316 chemicals have been digitized into standardized and structured toxicity data within the Toxicity Reference Database (ToxRefDB). Comparative analysis across the 329 studies identified chemicals with sensitive reproductive effects, based on comparisons to chronic and subchronic toxicity studies, as did the cross-generational comparisons within the multigeneration study. The general pattern of toxicity across all chemicals and the more focused comparative analyses identified 19 parental, offspring and reproductive effects with a high enough incidence to serve as targets for predictive modeling that will eventually serve as a chemical prioritization tool spanning reproductive toxicities. These toxicity endpoints included specific reproductive performance indices, male and female reproductive organ pathologies, offspring viability, growth and maturation, and parental systemic toxicities. Capturing this reproductive toxicity data in ToxRefDB supports ongoing retrospective analyses, test guideline revisions, and computational toxicology research.
[Martin, M, Mendez, E et al. 2009. Toxicol. Sci. 110 (1): 181-190.]
- Statistical Modeling Suggests That Anti-Androgens in Wastewater Treatment Works Effluents Are Contributing Causes of Widespread Sexual Disruption in Fish Living in English Rivers
In addition to the estrogenic substances, antiandrogenic activity was prevalent in almost all treated sewage effluents tested. Further, the results of the modeling demonstrated that feminizing effects in wild fish could be best modeled as a function of their predicted exposure to both antiandrogens and estrogens or to antiandrogens alone. Results provide a strong argument for a multicausal etiology of widespread feminization of wild fish in U.K. rivers involving contributions from both steroidal estrogens and xenoestrogens and from other (as yet unknown) contaminants with antiandrogenic properties. These results may add further credence to the hypothesis that endocrine-disrupting effects seen in wild fish and in humans are caused by similar combinations of endocrine-disrupting chemical cocktails.
[Jobling, S. et al. 2009. Environ Health Perspect 117:797-802. doi:10.1289/ehp.0800197]
- Synergistic Disruption of External Male Sex Organ Development by a Mixture of Four Antiandrogens
Study found the effect of combined exposure to four selected chemicals on malformations of external sex organs was synergistic, and the observed responses were greater than would be predicted from the toxicities of the individual chemicals. In relation to other hallmarks of disrupted male sexual development, including changes in anogenital distance (AGD), retained nipples, and sex organ weights, the combined effects were dose additive. When the four chemicals were combined at doses equal to no observed adverse effect levels estimated for nipple retention, significant reductions in AGD were observed in male offspring.
[Christiansen, S. et al. 2009. Environ Health Perspect 117:1839-1846]
- Testicular toxicity of chlorpyrifos (an organophosphate pesticide) in albino rat
Present study was undertaken to assess the effects of chlorpyrifos on testes, the main organ of male reproduction. Chlorpyrifos at the dose levels of 7.5, 12.5 and 17.5 mg/kg b. wt./day was administered orally to male rats of Wistar strain for 30 days. A significant reduction in weight was observed in testes. Chlorpyrifos also brought about marked reduction in epididymal and testicular sperm counts in exposed males and a decrease in serum testosterone concentration. Histopathological examination of testes showed mild to severe degenerative changes in seminiferous tubules at various dose levels. Fertility test showed 85% negative results. A significant reduction in the sialic acid content of testes and testicular glycogen was noticed, whereas the protein and cholesterol content was raised at significant levels. All these toxic effects are moderate at low doses and become severe at higher dose levels. From the results of the present study it is concluded that chlorpyrifos induces severe testicular damage and results in reduction in sperm count and thus affect fertility. Small changes in sperm counts are known to have adverse affects on human fertility. Therefore, application of such insecticide should be limited to a designed program.
[Joshi, S, Mathur, R and Gulati, N. 2007. Toxicology and Industrial Health. 23: 439—444]
- Association of in utero organochlorine pesticide exposure and fetal growth and length of gestation in an agricultural population.
Although substantial evidence exists for the fetal toxicity of organochlorines in animals, information on human reproductive effects is conflicting. Study investigated whether infants' length of gestation, birth weight, and crown-heel length were associated with maternal serum levels of 11 different organochlorine pesticides: p,p -dichlorodiphenyltrichloroethane (p,p -DDT), p,p -dichlorodiphenyldichloroethylene (p,p -DDE), o,p -dichlorodiphenyltrichloroethane (o,p -DDT), hexachlorobenzene (HCB), gamma-hexachlorocyclohexane (gamma-HCCH), gamma-hexachlorocyclohexane (gamma-HCCH), dieldrin, heptachlor epoxide, oxychlordane, trans-nonachlor, and mirex. Our subjects were a birth cohort of 385 low-income Latinas living in the Salinas Valley, an agricultural community in California. Results found no adverse associations between maternal serum organochlorine levels and birth weight or crown-heel length. Decreased length of gestation with increasing levels of lipid-adjusted HCB was found. Study did not find reductions in gestational duration associated with any of the other organochlorine pesticides. Study's finding of decreased length of gestation related to HCB does not seem to have had clinical implications for this population, given its relatively low rate of preterm delivery (6.5%).
[Fenster L, Eskenazi B, Anderson M, Bradman A. 2006. Environ Health Perspect. 114(4):597-602]
- Exposure to nonpersistent insecticides and male reproductive hormones.
Urinary metabolites of several nonpersistent insecticides have been measured in a high percentage of men in the general population, suggesting widespread environmental exposures to these compounds. The present study explored the association of urinary concentrations of 3,5,6-trichloro-2-pyridinol (TCPY), a metabolite of chlorpyrifos and chlorpyrifos-methyl, and 1-naphthol (1N), a metabolite of carbaryl and naphthalene, with serum reproductive hormone levels in adult men. Subjects (n = 268) were the male partners in couples presenting to a Massachusetts infertility clinic in years 2000 through 2003. TCPY and 1N were measured in a spot urine sample from each subject and adjusted for dilution using specific gravity. Reproductive hormones (follicle-stimulating hormone, leuteinizing hormone, inhibin B, testosterone, and sex hormone-binding globulin) were measured in serum collected from subjects during the same clinic visit. Multiple linear regression models showed an inverse association between TCPY and testosterone concentration. An interquartile range (IQR) increase in TCPY was associated with a decline of 25 ng/dL (95% confidence interval = -40 to -10) in testosterone concentration. The association appeared to be dose-dependent when exposure was divided into quintiles. The highest TCPY quintile was associated with a testosterone decline of 83 ng/dL (-128 to -39) compared with the lowest TCPY quintile. We also found inverse associations between TCPY and free androgen index and between 1N and testosterone, and suggestive inverse associations between TCPY and luteinizing hormone and between 1N and free androgen index. In adult men, TCPY and 1N were associated with reduced testosterone levels. On a population level, these reductions are of potential public health importance because of widespread exposure to these nonpersistent insecticides.
[Meeker JD, et al. 2006. Epidemiology;17(1):61-8]
- Impact of PCB and p, p'-DDE Contaminants on Human Sperm Y:X Chromosome Ratio: Studies in Three European Populations and the Inuit Population in Greenland
Recent studies indicate that persistent organohalogen pollutants (POPs) may contribute to sex ratio changes in offspring of exposed populations. Our aim in the present study was to investigate whether exposure to 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB-153) and dichlorodiphenyldichloroethene (p,p′-DDE) affects sperm Y:X chromosome distribution. We obtained semen and blood for analysis of PCB-153 and p,p′-DDE levels from 547 men from Sweden, Greenland, Poland (Warsaw), and Ukraine (Kharkiv), with regionally different levels of POP exposure. The proportion of Y- and X-chromosome–bearing sperm in the semen samples was determined by two-color fluorescence in situ hybridization analysis. Swedish and Greenlandic men had on average significantly higher proportions of Y sperm (in both cohorts, 51.2%) and correspondingly higher lipid-adjusted concentrations of PCB-153 (260 ng/g and 350 ng/g, respectively) compared with men from Warsaw (50.3% and 22 ng/g) and Kharkiv (50.7% and 54 ng/g). In the Swedish cohort, log-transformed PCB-153 and log-transformed p,p′-DDE variables were significantly positively associated with Y-chromosome fractions (p-values 0.04 and < 0.001, respectively). On the contrary, in the Polish cohort PCB-153 correlated negatively with the proportion of Y-bearing fraction of spermatozoa (p = 0.008). The present study indicates that POP exposure might be involved in changing the proportion of ejaculated Y-bearing spermatozoa in human populations. Intercountry differences, with different exposure situations and doses, may contribute to varying Y:X chromosome ratios.
[Tiido T, et al. 2006. Environ Health Perspect 114:718-724. doi:10.1289/ehp.8668]
- Epigenetic Transgenerational Actions of Endocrine Disruptors and Male Fertility
Transgenerational effects of environmental toxins require either a chromosomal or epigenetic alteration in the germ line. Transient exposure of a gestating female rat during the period of gonadal sex determination to the endocrine disruptors vinclozolin (an antiandrogenic compound) or methoxychlor (an estrogenic compound) induced an adult phenotype in the F1 generation of decreased spermatogenic capacity (cell number and viability) and increased incidence of male infertility. These effects were transferred through the male germ line to nearly all males of all subsequent generations examined (that is, F1 to F4). The effects on reproduction correlate with altered DNA methylation patterns in the germ line. The ability of an environmental factor (for example, endocrine disruptor) to reprogram the germ line and to promote a transgenerational disease state has significant implications for evolutionary biology and disease etiology.
[Anway, M.D. et al. 2005. Science: 308(5727) pp. 1466 - 1469]
- Exposure to persistent organochlorine pollutants associates with human sperm Y:X chromosome ratio
During the last decades, there has been concern that exposure to endocrine disruptors, such as persistent organochlorine pollutants (POPs), may contribute to sex ratio changes in offspring of exposed populations. To investigate whether exposure to 2,2'4,4'5,5'-hexachlorobiphenyl (CB-153) and dichlorodiphenyl dichloroethene (p,p'-DDE) affect Y:X chromosome proportion, semen of 149 Swedish fishermen, aged 27-67 years, was investigated. The men provided semen and blood for analysis of hormone, CB-153 and p,p'-DDE levels. The proportion of Y- and X-chromosome bearing sperm in semen samples was determined by two-color fluorescence in situ hybridization (FISH) analysis. Log transformed CB-153 as well as log transformed p,p'-DDE variables were both significantly positively associated with Y chromosome fractions (P-values = 0.05 and <0.001, respectively). Neither age, smoking nor hormone levels showed any association with Y-chromosome fractions. This is the first study to indicate that exposure to POPs may increase the proportion of ejaculated Y-bearing spermatozoa. These data add to the growing body of evidence that exposure to POPs may alter the offspring sex ratio.
[Tiido T, et al. 2005. Hum Reprod:20(7)1903-9]
- Methoxychlor Disrupts Uterine Hoxa10 Gene Expression
Study demonstrates that a mechanism by which methoxychlor disrupts uterine function is by suppressing Hoxa10 expression. Neonatal methoxychlor treatment resulted in an immediate suppression and cellular restriction of Hoxa10 expression as well as a permanent generalized decrease in expression that persisted in the adult. methoxychlor inhibited the expression of Hoxa10, a gene necessary for uterine development and function. One common mechanism by which endocrine disrupting chemicals produce lasting reproductive tract defects is through permanent alteration of developmental gene expression.
[Fei, X. et al. 2005. Endocrinology 146(8): 3445-3451]
- Low-Dose Agrochemicals and Lawn-Care Pesticides Induce Developmental Toxicity in Murine Preimplantation Embryos
Mixtures simulating preemergent herbicides, postemergent herbicides, and fungicides increased the percentage of apoptosis in exposed embryos (p ≤ 0.05). Mixtures simulating groundwater contaminants, insecticide formulation, and lawn-care herbicides reduced development to blastocyst and mean cell number per embryo (p ≤ 0.05). Our data demonstrate that pesticide-induced injury can occur very early in development, with a variety of agents, and at concentrations assumed to be without adverse health consequences for humans.
[Greenlee, A., et al. 2004. Environmental Health Perspectives, 112(6): 703-709.]
- Effect of Endosulfan on Male Reproductive Development
There is experimental evidence of adverse effects of endosulfan on the male reproductive system, but there are no human data. Therefore, we undertook a study to examine the relationship between environmental endosulfan exposure and reproductive development in male children and adolescents. The study population was composed of 117 male schoolchildren (10-19 years of age) of a village situated at the foothills of cashew plantations, where endosulfan had been aerially sprayed for more than 20 years, and 90 comparable controls with no such exposure history. The study parameters included recording of clinical history, physical examination, sexual maturity rating (SMR) according to Tanner stages, and estimation of serum levels of testosterone, luteinizing hormone (LH), follicle-stimulating hormone, and endosulfan residues (70 study and 47 control subjects). Mean +/- SE serum endosulfan levels in the study group (7.47 +/- 1.19 ppb) were significantly higher (p < 0.001) than in controls (1.37 +/- 0.40 ppb). Multiple regression analysis showed that SMR scoring for development of pubic hair, testes, penis, and serum testosterone level was positively related to age and negatively related to aerial exposure to endosulfan (AEE; p < 0.01). Serum LH levels were significantly positively related to AEE after controlling for age (p < 0.01). The prevalence of congenital abnormalities related to testicular descent (congenital hydrocele, undescended testis, and congenital inguinal hernia) among study and controls subjects was 5.1% and 1.1%, respectively, but the differences were statistically nonsignificant. Our study results suggest that endosulfan exposure in male children may delay sexual maturity and interfere with sex hormone synthesis. Our study is limited by small sample size and nonparticipation.
[Saiyed, H et al. 2003. Environ Health Perspect 111:1958-1962]
- Geographic differences in semen quality of fertile U.S. males.
Although geographic variation in semen quality has been reported, this is the first study in the United States to compare semen quality among study centers using standardized methods and strict quality control. We evaluated semen specimens from partners of 512 pregnant women recruited through prenatal clinics in four U.S. cities during 1999-2001; 91% of men provided two specimens. Sperm concentration, semen volume, and motility were determined at the centers, and morphology was assessed at a central laboratory. Study protocols were identical across centers, and quality control was rigorously maintained. Sperm concentration was significantly lower in Columbia, Missouri, than in New York, New York; Minneapolis, Minnesota; and Los Angeles, California. Mean counts were 58.7, 102.9, 98.6, and 80.8 X 10(6)/mL (medians 53.5, 88.5, 81.8, and 64.8 X 10(6)/mL) in Missouri, New York, Minnesota, and California, respectively. The total number of motile sperm was also lower in Missouri than in other centers: 113, 196, 201, and 162 X 10(6) in Missouri, New York, Minnesota, and California, respectively. Semen volume and the percent morphologically normal sperm did not differ appreciably among centers. These between-center differences remained significant in multivariate models that controlled for abstinence time, semen analysis time, age, race, smoking, history of sexually transmitted disease, and recent fever (all p-values < 0.01). Confounding factors and differences in study methods are unlikely to account for the lower semen quality seen in this mid-Missouri population. These data suggest that sperm concentration and motility may be reduced in semirural and agricultural areas relative to more urban and less agriculturally exposed areas.
[Swan, S. et al. 2003. Environ Health Perspect; 111(4): 414–420]
- Risk factors for female infertility in an agricultural region
Mixing and applying herbicides 2 years before attempting conception was more common among infertile women (odds ratio [OR] = 27; 95% confidence interval [CI] = 1.9-380), as was the use of fungicides (OR = 3.3; CI = 0.8-13). Residing on a farm, ranch or in a rural area during this time period was protective of female fertility. Households supplied with central Wisconsin groundwater were at less risk for infertility than households using municipal sources (OR = 0.6; CI = 0.4-0.9). These results suggest that certain agricultural, residential and lifestyle choices may modify the risk of female infertility.
[Greenlee AR, et al. 2003. Epidemiology;14(4):429-36]
- Semen quality in relation to biomarkers of pesticide exposure.
Study addresses the hypothesis that pesticides currently used in agriculture in the Midwest contributed to these differences in semen quality. Men from Missouri with high levels of alachlor or diazinon in thier urine were significantly more likely to have poor sperm quality than were men with low levels, as were men with atrazine levels higher than the limit of detection (OR = 11.3). The herbicides 2,4-D and metolachlor were associated with poor semen quality in some analyses, whereas acetochlor levels were lower in cases than in controls (p = 0.04). No significant associations were seen for any pesticides within Minnesota, where levels of agricultural pesticides were low, or for the insect repellent DEET or the malathion metabolite malathion dicarboxylic acid. These associations between current-use pesticides and reduced semen quality suggest that agricultural chemicals may have contributed to the reduction in semen quality in fertile men from mid-Missouri reported previously.
[Swan, S.H. et al. 2003. Environ Health Perspect; 111(12): 1478–1484]
- Developmental Toxicity of a Commercial Herbicide Mixture in Mice: I. Effects on Embryo Implantation and Litter Size
We investigated the developmental toxicity in mice of a common commercial formulation of herbicide containing a mixture of 2,4-dichlorophenoxyacetic acid (2,4-D), mecoprop, dicamba, and inactive ingredients. Pregnant mice were exposed to one of four different doses of the herbicide mixture diluted in their drinking water, either during preimplantation and organogenesis or only during organogenesis. Litter size, birth weight, and crown-rump length were determined at birth, and pups were allowed to lactate and grow without additional herbicide exposure so that they could be subjected to additional immune, endocrine, and behavioral studies, the results of which will be reported in a separate article. At weaning, dams were sacrificed, and the number of implantation sites was determined. The data, although apparently influenced by season, showed an inverted or U-shaped dose-response pattern for reduced litter size, with the low end of the dose range producing the greatest decrease in the number of live pups born. The decrease in litter size was associated with a decrease in the number of implantation sites, but only at very low and low environmentally relevant doses. Fetotoxicity, as evidenced by a decrease in weight and crown-rump length of the newborn pups or embryo resorption, was not significantly different in the herbicide-treated litters.
[Cavieres, M., et al. 2002. Environ Health Perspect 110:1081-1085]
- Reproductive Toxicity of Carbofuran to the Female Mice: Effects on Estrous Cycle and Follicles
Carbofuran, a systemic N-methyl carbamate pesticide was orally administered with the doses of 0.4, 0.7, 1 and 1.3 mg/kg body weight/day to normal virgin female Swiss albino mice for 30 days. Estrous cycle was effected by showing a significant decrease in the number of estrous cycle and the duration of each phases of estrous cycle with concomitant significant increase in the diestrus phase in 1 and 1.3 mg/kg/d carbofuran treatment when compared with that of control mice. There was a significant decrease in the number of healthy follicles and a significant increase in the number of atretic follicles in 1 and 1.3 mg/kg/d treated groups when compared with the control. The histologic observations of the ovary revealed the presence of less number of healthy follicles and more number of atretic follicles in high dose of carbofuran treated mice. There was a dose dependent decrease in the body weight. The ovary weight was also decreased significantly in 1.3mg/kg/d carbofuran treatment. There were no significant change in the weight of the organs such as uterus, kidney, adrenal, liver, spleen, thymus and thyroid. These observed effects of carbofuran on the estrous cycle and follicles may be due to a direct effect on the ovary or the hypothalamo-hypophysial ovarian axis causing hormonal imbalance.
[BALIGAR, PN, KALIWAL, BB. 2002. Industrial Health. 40(4):345-352]
- An exploratory analysis of the effect of pesticide exposure on the risk of spontaneous abortion in an Ontario farm population.
The Ontario Farm Family Health Study collected data by questionnaire on the identity and timing of pesticide use on the farm, lifestyle factors, and a complete reproductive history from the farm operator and eligible couples living on the farm. A total of 2,110 women provided information on 3,936 pregnancies, including 395 spontaneous abortions. To explore critical windows of exposure and target sites for toxicity, authors examined exposures separately for preconception (3 months before and up to month of conception) and postconception (first trimester) windows and for early (< 12 weeks) and late (12-19 weeks) spontaneous abortions. They observed moderate increases in risk of early abortions for preconception exposures to phenoxy acetic acid herbicides, triazines, and any herbicide. For late abortions, preconception exposure to glyphosate, thiocarbamates, and the miscellaneous class of pesticides was associated with elevated risks. This study shows that timing of exposure and restricting analyses to more homogeneous endpoints are important in characterizing the reproductive toxicity of pesticides.
[Arbuckle,TE, Lin, Z and Mery, LS. 2001. Environ Health Perspect. 109(8): 851–857.]
- Contribution of environmental factors to the risk of male infertility
An increasing number of reports suggest that chemical and physical agents in the environment, introduced and spread by human activity, may affect male fertility in humans. We investigated the relationships between exposure to environmental agents and seminal characteristics, and the concentrations of reproductive hormones in the serum of men seeking infertility treatment. We studied 225 male partners from consecutively recruited couples, who had their first infertility consultation between 1995 and 1998, in the Litoral Sur region of Argentina, one of the most productive farming regions in the world. A multivariate logistic regression model showed that exposure to pesticides and solvents is significantly associated with sperm threshold values well below the limit for male fertility. We also found that men exposed to pesticides had higher serum oestradiol concentrations, and that men exposed to solvents had lower LH concentrations than non-exposed men. All of these effects were greater in men with primary infertility than in men with secondary infertility. We have shown that environmental factors contribute to the severity of infertility, and that this may worsen the effects of pre-existing genetic or medical risk factors.
[Oliva A, et al. 2001. Hum Reprod;16(8):1768-76]
- Environmental risk factors and male fertility and reproduction
Several environmental substances and pesticides exert a direct, cytotoxic effect on male germ cells. However, an increasing concern has been raised by compounds that may act through more subtle mechanisms, for example, specific pesticides that are potentially capable of modulating or disrupting the endocrine system. Overall, exposure to pesticides with endocrine-disrupting potential raise a particular concern for male fertility because of the possible occurrence of both effects at low concentrations and additive interactions with other environmental risk factors. Delayed reproductive problems deserve special attention, since experimental data consistently indicate a high vulnerability in the developing male reproductive system. Epidemiologic studies have confirmed an increased risk of conception delay associated with occupational exposure to pesticides. Moreover, an increased risk of spontaneous abortion has been noted among wives of exposed workers.
[Petrelli, G and Mantovani, A. 2001. Contraception. 65(4):297–300]
- Evaluation of the Toxic Potentials of Cypermethrin Pesticide on Some Reproductive and Fertility Parameters in the Male Rats
Adult male Sprague-Dawley rats were exposed to tap water containing 0, 8,571, 17,143, or 34,286 ppm cypermethrin for 12 weeks. Fertility was significantly reduced in male rats ingesting cypermethrin at a concentration of 13.15 and 18.93 mg in that the number of females impregnated by them was significantly reduced. The number of implantation sites was significantly reduced in females mated with males that had ingested cypermethrin at a concentration of 39.66 mg. A significant reduction in the number of viable fetuses was observed in females impregnated by the exposed males at all three doses of cypermethrin. Epididymal and testicular sperm counts as well as daily sperm production were significantly decreased in exposed males. The serum levels of testosterone, follicle-stimulating hormone and luteinizing hormone were significantly reduced in males exposed to 39.66 mg per day. Ingestion of cypermethrin at 18.93 and 39.66 mg/animal/day also resulted in a significant decrease in the perimeter and number of cell layers of the seminiferous tubules. The testes of treated animals were infiltrated with congested blood vessels with marked hemorrhage and a significant accumulation of connective tissue surrounding the seminiferous tubules, which contained a large number of immature spermatids. These results clearly demonstrate the adverse effects of cypermethrin pesticide on fertility and reproduction in male rats.
[Elbetieha, A, Da'as, SI et al. 2001. Arch Environ Contamn Tox. 41(4):522-528]
- Reproductive toxicity of DDT in adult male rats
The reproductive toxicity of DDT was investigated in adult male rats. Administration of DDT led to a dose-dependent reduction of testicular weight and the number as well as the percentage of motile spermatozoa in the epididymis. Testicular histological observations revealed alsoamarkedloss of gametes in the lumen of seminiferous tubules. In DDT treated rats, the seminal vesicles weights dropped significantly, resulting from a decrease of testosterone production by testes, whereas serum LH and FSH increased after pesticide exposure. This increase of gonadotrophin levels may be related to an impairment of the negative feedback exerted by the steroid on the hypothalamic–pituitary axis. It is concluded that DDT induced adverse effects on male rat fertility by acting directly on the testes and altering the neuroendocrinefunction.
[Rhouma, KB, Tebourbi et al. 2001. Hum Exp Toxicol 20(8):393-397]
- Environmental antiandrogens: low doses of the fungicide vinclozolin alter sexual differentiation of the male rat.
In humans and rodents, exposure to antiandrogenic chemicals during sexual differentiation can produce malformations of the reproductive tract. Perinatal administration of 100 or 200 mg vinclozolin (V) kg-1 day-1 during sexual differentiation in rats induces female-like anogenital distance (AGD), retained nipples, cleft phallus with hypospadias, suprainguinal ectopic scrota/testes, a vaginal pouch, epididymal granulomas, and small to absent sex accessory glands in male offspring. Vinclozolin is metabolized to at least two active forms, M1 and M2, that display antiandrogenic activity by binding the androgen receptor (AR). Here, we present information on the reproductive effects of oral treatment with low dosage levels of V during sexual differentiation of the male rat. Vinclozolin was administered to the dam at 0, 3.125, 6.25, 12.5, 25, 50, or 100 mg kg-1 day-1 from gestational day 14 to postnatal day 3 (the period of fetal/neonatal testicular testosterone synthesis and sexual differentiation). At doses of 3.125 mg V kg-1 and above, AGD was significantly reduced in newborn male offspring and the incidence of areolas was increased. These effects were associated with permanent alterations in other androgen-dependent tissues. Ventral prostate weight in one year old male offspring was reduced in all treatment groups (significant at 6.25, 25, 50, and 100 mg kg-1 day-1), and permanent nipples were detected in males at 3.125 (1.4%), 6.25 (3.6%), 12.5 (3.9%), 25 (8.5%), 50 (91%), and 100 (100%) mg V kg-1 day-1. To date, permanent nipples have not been observed in a control male from any study in our laboratory. Vinclozolin treatment at 50 and 100 mg kg-1 day-1 induced reproductive tract malformations and reduced ejaculated sperm numbers and fertility. Even though all of the effects of V likely result from the same initial event (AR binding), the different endpoints displayed a wide variety of dose-response curves and ED50's. The dose-response data for several of the functional endpoints failed to display an obvious threshold. These data demonstrate that V produces subtle alterations in sexual differentiation of the external genitalia, ventral prostate, and nipple tissue in male rat offspring at dosage levels below the previously described no-observed-effect-level (NOEL). These effects occur at a dosage level an order of magnitude below that required to induce malformations and reduce fertility. Hence, multigenerational reproduction studies of antiandrogenic chemicals that were not conducted under the Environmental Protection Agency's new Harmonized Multigenerational Test Guidelines, which include endpoints sensitive to antiandrogens at low dosage levels, could yield a NOEL that is at least an order of magnitude too high.
[Gray LE, et al. 1999. Toxicol Ind Health;15(1-2):48-64]
- Effects of Pesticides and Toxic Substances On Behavioral and Morphological Reproductive Development: Endocrine Versus Nonendocrine Mechanisms
Exposure to toxic substances or pesticides during critical perinatal developmental periods can alter reproductive and central nervous system (CNS)function in a manner that does not compromise the growth and viability of the fetus but causes functional alterations that become apparent later in life. While some "CNS/behavioral teratogens" are mutagenic or alter cell division, other chemicals produce alterations of CNS development via endocrine-mediated mechanisms. This discussion focuses on studies conducted primarily in our laboratory that describe how pesticides and toxic substances alter development of the reproductive and central nervous systems as a consequence of organizational or activational exposures. Abnormal behavior and morphology can result from exposure to endocrine-disrupting toxicants by altering organization of the CNS during critical stages of life or activation of behavior after puberty. Some of the toxicants that alter rodent sexual differentiation include xenoestrogens, antiandrogenic pesticides, and dioxin-like toxic substances. Chemicals that alter sex-linked nonreproductive and reproductive CNS development via nonhormonal mechanisms are also discussed in order to demonstrate that multiple mechanisms of action are involved in the development of behavioral abnormalities in pre- and perinatally exposed offspring. The fact that reproductive function (behavioral, biochemical, and morphological) can be altered via such a wide variety of mechanisms indicates that hazard identification in this area cannot rely solely on the detection of endocrine activity.
[Gray, LE and Ostby, J. 1998. Toxicol Ind Health 14(1-2): 159-184]
- Latent Effects of Pesticides and Toxic Substances On Sexual Differentiation of Rodents
The current discussion presents information on the effects of toxic chemicals and pesticides that act on reproductive development via novel mechanisms, including germ cell toxicity, antiandrogenicity, and Ah-receptor binding. Information will be presented that describes how exposure during critical stages of life to synthetic chemicals present in our environment, such as benzidine- based dyes, antiandrogenic fungicides, 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD), and PCB congener 169, result in abnormal rodent sex differentiation. In rodents, perinatal exposure to fetal germ cell toxicants reduced the reproductive potential of female, and permanently reduced sperm production in male progeny. Phenotypic sex differentiation, however, was unaffected by these germ cell toxicants. In contrast, antiandrogenic drugs and fungicides induced profound alterations in phenotypic sex differentiation. Effects such as hypospadias, ectopic testes, vaginal pouches, agenesis of the ventral prostate, and nipple retention in male rats were observed commonly. Although these antiandrogens induced no permanent effects in female progeny, another class of chemicals, the Ah-receptor mediated toxicants, did reduce fertility in both male and female rat offspring. Other toxicants produced dramatic alterations of sex differentiation (uterus unicornis, agenesis of the vas and epididymis, and undescended testes), via mechanisms that have not been characterized yet. Since these adult/pubertal alterations resulted from gestational and/or neonatal exposures, future studies should include a comprehensive assessment of reproductive function after perinatal exposure because the developing animal is extremely sensitive to toxicants during sex differentiation, and many of the effects are difficult to detect until late in life.
[Gray, LE and Kelce, W. 1996. Toxicol Ind Health.12(3-4): 515-531]
- Developmental effects of endocrine-disrupting chemicals in wildlife and humans.
Large numbers and large quantities of endocrine-disrupting chemicals have been released into the environment since World War II. Many of these chemicals can disturb development of the endocrine system and of the organs that respond to endocrine signals in organisms indirectly exposed during prenatal and/or early postnatal life; effects of exposure during development are permanent and irreversible. The risk to the developing organism can also stem from direct exposure of the offspring after birth or hatching. In addition, transgenerational exposure can result from the exposure of the mother to a chemical at any time throughout her life before producing offspring due to persistence of endocrine-disrupting chemicals in body fat, which is mobilized during egg laying or pregnancy and lactation. Mechanisms underlying the disruption of the development of vital systems, such as the endocrine, reproductive, and immune systems, are discussed with reference to wildlife, laboratory animals, and humans.
[Colborn, T, vom Saal, FS, and Soto, AM. 1993. Environ Health Perspect. 101(5): 378–384]
- Prevalence of adverse reproductive outcomes in a population occupationally exposed to pesticides in Colombia
A prevalence survey of adverse reproductive outcomes was carried out in a population of 8867 persons (2951 men and 5916 women) who had been working in the floriculture industry in the Bogotá area of Colombia for at least six months. These workers were exposed to 127 different types of pesticides. The prevalence rates for abortion, prematurity, stillbirths, and malformations were estimated for pregnancies occurring among the female workers and the wives of the male workers before and after they started working in floriculture, and these rates were related to various degrees of exposure. A moderate increase in the prevalence of abortion, prematurity, and congenital malformations was detected for pregnancies occurring after the start of work in floriculture.
[Restrepo, M, Muñoz, N et al. 1990. Scandinavian Journal of Work, Environment & Health.16(4):232-238]