This study investigates the structural and mechanical changes in uterine collagen following exposure to propylparaben (PP) using a combined methodology of Second Harmonic Generation (SHG) microscopy, Nanoindentation (NI), and Atomic Force Microscopy (AFM). SHG analysis identified significant disorganization in collagen fibril orientation in the circumferential layer and heterogeneous distribution of regions with elevated forward to backward ratios (F/B) across all uterine layers due to PP exposure. High F/B can indicate multiple potential fibril-level changes like thickened fibrils, higher crosslinking, fibril disorganization - changes not fully decipherable by SHG alone. Recognizing this limitation, the study employs NI and AFM to provide complementary mechanical and nanoscale insights. NI revealed increased indentation modulus in the exposed uteri, suggesting increased stiffness. Co-registration of the indentation response with SHG parameters uncovered that elevated F/B regions show enhanced mechanical stiffness, suggesting a fibrotic transformation following chronic PP exposure. AFM was specifically performed on regions identified by SHG as having low or high F/B, providing the necessary nanoscale resolution to elucidate the structural changes in fibrils that are likely responsible for the observed alterations. AFM confirmed the presence of disordered and entangled collagen fibrils in the circumferential layer in all regions and an increase in fibril diameter in the high F/B regions in the PP-exposed uteri. Together, these findings demonstrate significant alterations in collagen architecture due to PP exposure, revealing disruptions at both the fiber and fibril levels and highlighting the potential for broader applications of the multi-scale, multi-modal approach in collagenous tissue studies.

Human health depends on planetary health, and yet healthcare provision can have unintended consequences for the health of the planet. Emissions from the healthcare sector include greenhouse gases, air pollution and plastic pollution, alongside chemical contamination. Chemical pollution resulting in endocrine disruption has been associated with plastics, which are a source of concerning additives such as phthalates, bisphenols, perfluoroalkyl and polyfluoroalkyl substances, and flame retardants (all routinely found in healthcare products). Many endocrine-disrupting chemicals are persistent and ubiquitous in the environment (including water and food sources), with potential secondary harms for human health, including disrupting reproductive, metabolic and thyroid function. Here we review evidence-based strategies for mitigating environmental effects of healthcare delivery. We focus on what endocrinologists can do, including reducing demand for healthcare services through better preventative health, focusing on high-value care and improving sustainability of medical equipment and pharmaceuticals through adopting circular economy principles (including reduce, reuse and, as a last resort, recycle). The specific issue of endocrine-disrupting chemicals might be mitigated through responsible disposal and processing, alongside advocating for the use of alternative materials and replacing additive chemicals with those that have lower toxicity profiles, as well as tighter regulations. We must work to urgently transition to sustainable models of care provision, minimizing negative effects on human and planetary health.

The epigenome and epigenetic inheritance were not included in the original modern synthesis theory or more recent extended evolutionary synthesis of evolution. In a broad range of species, the environment has been shown to play a significant role in natural selection, which more recently has been shown to occur through epigenetic alterations and epigenetic inheritance. However, even with this evidence, the field of epigenetics and epigenetic inheritance has been left out of modern evolutionary synthesis, as well as other current evolutionary models. Epigenetic mechanisms can direct the regulation of genetic processes (e.g. gene expression) and also can be directly changed by the environment. In contrast, DNA sequence cannot be directly altered by the environment. The goal of this review is to present the evidence of how epigenetics and epigenetic inheritance can alter phenotypic variation in numerous species. This can occur at a significantly higher frequency than genetic change, so correlates with the frequency of evolutionary change. In addition, the concept and importance of generational stability of transgenerational inheritance is incorporated into evolutionary theory. For there to be a better understanding of evolutionary biology, we must incorporate all aspects of molecular (e.g. genetics and epigenetics) and biological sciences (e.g. environment and adaptation).

This study investigates the structural and mechanical changes in uterine collagen following exposure to propylparaben (PP), using a combined methodology of Second Harmonic Generation (SHG) microscopy, Nanoindentation (NI), and Atomic Force Microscopy (AFM). SHG analysis identified significant disorganization in collagen fibril orientation in the circumferential layer and heterogeneous distribution of regions with elevated forward to backward ratios (F/B) across all uterine layers due to PP exposure. High F/B can indicate multiple potential fibril-level changes like thickened fibrils, higher crosslinking, fibril disorganization - changes not fully decipherable by SHG alone. Recognizing this limitation, the study employs NI and AFM to provide complementary mechanical and nanoscale insights. NI revealed increased indentation modulus in the exposed uteri, suggesting increased stiffness. Co-registration of the indentation response with SHG parameters uncovered that elevated F/B regions show enhanced mechanical stiffness, suggesting a fibrotic transformation following PP exposure. AFM was specifically performed on regions identified by SHG as having low or high F/B, providing the necessary nanoscale resolution to elucidate the structural changes in fibrils that are likely responsible for the observed alterations. This approach confirmed the presence of disordered and entangled collagen fibrils in the circumferential layer in all regions and an increase in fibril diameter in the high F/B regions in the exposed uteri. Together, these findings demonstrate significant alterations in collagen architecture due to PP exposure, revealing disruptions at both the fiber and fibril levels and highlighting the potential for broader applications of the multi-scale, multi-modal approach in collagenous tissue studies.

The increase in female reproductive disorders, such as polycystic ovary syndrome, endometriosis, and diminished ovarian reserve that lead to subfertility and infertility, has encouraged researchers to search and discover their underlying causes and risk factors. One of the crucial factors that may influence the increasing number of reproductive issues is environmental pollution, particularly exposure to man-made endocrine-disrupting chemicals (EDCs). EDCs can interfere with the ovarian microenvironment, impacting not only granulosa cell function but also other surrounding ovarian cells and follicular fluid (FF), which all play essential roles for oocyte development, maturation, and overall reproductive function. FF surrounds developing oocytes within an ovarian follicle and represents a dynamic milieu. EDCs are usually found in biological fluids, and FF is therefore of interest in this respect. This narrative review examines the current knowledge on specific classes of EDCs, including industrial chemicals, pesticides, and plasticizers, and their known effects on hormonal signaling pathways, gene expression, mitochondrial function, oxidative stress induction, and inflammation in FF. We describe the impact of EDCs on the development of reproductive disorders, oocyte quality, menstrual cycle regulation, and their effect on assisted reproductive technique outcomes. The potential transgenerational effects of EDCs on offspring through animal and first-human studies has been considered also. While significant progress has been made, the current understanding of EDCs' effects on ovarian function, particularly in humans, remains limited, underscoring the need for further research to clarify actions and effects of EDCs in the ovary.

Over the recent years, scientific community has increased its interest on solving problems of female fertility pathology. Many factors acting separately or in combination affect significantly the reproductive life of a woman. This review summarizes current evidence regarding the direct and/or indirect action of environmental factors and endocrine disrupting chemicals (EDCs; i.e. heavy metals, plasticizers, parabens, industrial chemicals, pesticides, or medications, by-products, anti-bacterial agents, perfluorochemicals) upon assisted and non-assisted female fertility, extracted from in vivo and in vitro animal and human published data. Transgenerational effects which could have been caused epigenetically by the action of EDCs have been raised.

This narrative review englobes and describes data from in vitro and in vivo animal and human studies with regard to the action of environmental factors, which include EDCs, on female fertility following the questions for narrative reviews of the SANRA (a scale for the quality assessment of narrative review articles). The identification of the studies was done: through the PubMed Central and the PubMed of the MEDLINE, the Google Scholar database and the Cochrane Library database until December 2023 combining appropriate keywords ("specific environmental factors" including "EDCs" AND "specific negative fertility outcomes"); by manual scanning of references from selected articles and reviews focusing on these subjects. It includes references to EDCs-induced transgenerational effects.

From the reported evidence emerge negative or positive associations between specific environmental factors or EDCs and infertility outcomes such as infertility indices, disrupted maturation of the oocytes, anovulation, deranged transportation of the embryo and failure of implantation.

The revealed adverse outcomes related to female fertility could be attributed to exposure to specific environmental factors such as temperature, climate, radiation, air pollutants, nutrition, toxic substances and EDCs. The recognition of fertility hazards related to the environment will permit the limitation of exposure to them, will improve female fertility and protect the health potential of future generations.

Isobutyronitrile finds extensive application in organic synthesis for the production of the insecticide diazinon. Apart from occupational exposure, cigarette smoking may also expose the general population to isobutyronitrile. However, to date, the association between isobutyronitrile and female infertility has not been explored in a population-based study. Hence, we analysed data from 1254 women, aged 18-44, with blood isobutyronitrile results and infertility questionnaires, from National Health and Nutrition Examination Survey (NHANES) 2015-2016 and NHANES 2017-March 2020. To compare differences, weighted chi-square tests were conducted for categorical variables and weighted regression models were performed for continuous variables. Logistic regression and generalized linear models were applied to examine the associations. Each standard deviation increment (SD=0.026) of isobutyronitrile increased the risk of infertility by 24 % after adjusting for potential confounders in logistic regression model (aOR=1.24; 95 % CI: 1.06-1.46). In women who had been pregnant and gave birth, the results exhibited a consistent linear relationship. The participants were classified into two groups, namely positive and negative, using an isobutyronitrile cut-off value that exceeded 0.040 ng/mL. The positive group did not demonstrate a statistically significant correlation (aOR=1.55; 95 % CI: 0.66-3.65). According to smooth curve fitting, isobutyronitrile and infertility was linearly related across the entire range, and no threshold effect was found. Particularly, non-Hispanic Black women had a significantly stronger association with isobutyronitrile exposure and infertility (aOR=4.27; 95 % CI: 1.32-13.83). In conclusion, our study was the first report of an independent association of isobutyronitrile with infertility, especially in non-Hispanic Black women. Additional fundamental research on nonhuman primates, along with comprehensive clinical studies, are necessary to fully elucidate the intricate mechanisms underlying isobutyronitrile activity.

The study encompassing research papers documented in the last two decades pertaining to the possible influence of bisphenol A (BPA) on the fertility of females are appraised with emphasis on the influence of BPA in reproductive organs (uterus and ovaries) and pregnancy outcomes including discussion on the reproductive process (implantation, estrous cycle, hormone secretion); outcomes reveal a connection amongst BPA and female infertility. Ovary, uterus, and its shape as well as function can alter a person's ability to become pregnant by influencing the hypothalamus-pituitary axis in the ovarian model. Additionally, implantation and the estrous cycle may be affected by BPA. However, more research is warranted to comprehend the underlying action mechanisms and to promptly identify any imminent reproductive harm.

Dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) are two typical non-volatile disinfection by-products (DBPs) found in drinking water. Increasing evidence has demonstrated that they show reproductive toxicity. However, whether they might have endocrine disrupting properties remains largely unknown. To discover this, we treated male mice or pregnant mice with 0, 1-, 102-, 103-, 104-, or 5 × 104-fold maximal concentration level (MCL) of DCAA or TCAA in drinking water. In male mice, the levels of testosterone in serum and androgen receptor (AR) in testis were declined with ≥ 103-fold MCL of DCAA (26.4 mg/kg/d) or TCAA (52.7 mg/kg/d). In pregnant mice, miscarriage rates were increased with ≥ 104-fold MCL of DCAA (264 mg/kg/d) or ≥ 103-fold MCL of TCAA. The levels of FSH in serum were increased and those of estradiol and progesterone were reduced with ≥ 103-fold MCL of DCAA or TCAA. The protein levels of estrogen receptors (ERα and ERβ) in ovary were reduced with ≥ 102-fold MCL of DCAA (2.64 mg/kg/d) or TCAA (5.27 mg/kg/d). Exposure to some certain fold MCL of DCAA or TCAA also altered the protein levels of ERα and ERβ in uterus and placenta. Exposure to 5 × 104-fold MCL of both DCAA and TCAA showed the combined effects. Therefore, both DCAA and TCAA could be considered as novel reproductive endocrine disrupting chemicals, which might be helpful for further assessment of the toxicological effects of DCAA and TCAA and the awareness of reproductive endocrine disrupting properties caused by DCAA and TCAA in drinking water.

Reproductive disorders are considered a global health problem influenced by physiological, genetic, environmental, and lifestyle factors. The increased exposure to bisphenols, a chemical used in large quantities for the production of polycarbonate plastics, has raised concerns regarding health risks in humans, particularly their endocrine-disrupting effects on female reproductive health. To provide a basis for future research on environmental interference and reproductive health, we reviewed relevant studies on the exposure patterns and levels of bisphenols in environmental matrices and humans (including susceptible populations such as pregnant women and children). In addition, we focused on in vivo, in vitro, and epidemiological studies evaluating the effects of bisphenols on the female reproductive system (the uterus, ovaries, fallopian tubes, and vagina). The results indicate that bisphenols cause structural and functional damage to the female reproductive system by interfering with hormones; activating receptors; inducing oxidative stress, DNA damage, and carcinogenesis; and triggering epigenetic changes, with the damaging effects being intergenerational. Epidemiological studies support the association between bisphenols and diseases such as cancer of the female reproductive system, reproductive dysfunction, and miscarriage, which may negatively affect the establishment and maintenance of pregnancy. Altogether, this review provides a reference for assessing the adverse effects of bisphenols on female reproductive health.

The Consortium Linking Academic and Regulatory Insights on Bisphenol A Toxicity (CLARITY-BPA) was a collaborative research effort to better link academic research with governmental guideline studies. This review explores the secondary goal of CLARITY-BPA: to identify endpoints or technologies from CLARITY-BPA and prior/concurrent literature from these laboratories that may enhance the capacity of rodent toxicity studies to detect endocrine disrupting chemicals (EDCs).

A systematic literature search was conducted with search terms for BPA and the CLARITY-BPA participants. Relevant studies employed a laboratory rodent model and reported results on 1 of the 10 organs/organ systems evaluated in CLARITY-BPA (brain and behavior, cardiac, immune, mammary gland, ovary, penile function, prostate gland and urethra, testis and epididymis, thyroid hormone and metabolism, and uterus). Study design and findings were summarized, and a risk-of-bias assessment was conducted.

Several endpoints and methods were identified as potentially helpful to detect effects of EDCs. For example, molecular and quantitative morphological approaches were sensitive in detecting alterations in early postnatal development of the brain, ovary, and mammary glands. Hormone challenge studies mimicking human aging reported increased susceptibility of the prostate to disease following developmental BPA exposure. Statistical analyses for nonmonotonic dose responses, and computational approaches assessing multiple treatment-related outcomes concurrently in linked hormone-sensitive organ systems, reported effects at low BPA doses.

This review provided an opportunity to evaluate the unique insights provided by nontraditional assessments in CLARITY-BPA to identify technologies and endpoints to enhance detection of EDCs in future studies.

Significant decreases in fertility have been observed over the past 50 years, with female conception rates dropping by 44% and male sperm counts decreasing by over 50%. This dramatic decrease in fertility can be attributed in part to our increasing exposure to endocrine disrupting chemicals (EDCs). Diethylstilbestrol (DES) is an estrogenic EDC that was prescribed to millions of pregnant women between 1940 and 1970 and resulted in detrimental reproductive effects in the offspring that were exposed in utero. Women who were exposed to DES in utero experienced higher rates of infertility, pregnancy complications, and reproductive cancers. Alarmingly, there is evidence to suggest that these effects may persist in the grandchildren and great grandchildren of exposed women. To define the transgenerational reproductive impacts in females following exposure to DES, gestating mice were exposed to DES and the effects monitored in the female descendants across 3 generations. There was a trend for reduced pregnancy rate and fertility index seen across the generations and moreover, the anogenital distance (AGD) was significantly reduced up until the third, unexposed generation. The onset of puberty was also significantly affected, with the timing of vaginal opening occurring significantly earlier in DES descendants. These results indicate a transgenerational effect of DES on multiple reproductive parameters including fertility, timing of puberty, and AGD. These data have significant implications for more than 50 million DES descendants worldwide as well as raising concerns for the ongoing health impacts caused by exposures to other estrogenic EDCs which are pervasive in our environment.

Phthalates are found in plastic food containers, medical plastics, and personal care products. However, the effects of long-term phthalate exposure on female reproduction are unknown. Thus, this study investigated the effects of long-term, dietary phthalate exposure on estrous cyclicity and fertility in female mice. Adult female CD-1 mice were fed chow containing vehicle control (corn oil) or 0.15-1500 ppm of di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DiNP), or a mixture of phthalates (Mix) containing DEHP, DiNP, benzyl butyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, and diethyl phthalate. Measurements of urinary phthalate metabolites confirmed effective delivery of phthalates. Phthalate consumption for 11 months did not affect body weight compared to control. DEHP exposure at 0.15 ppm for 3 and 5 months increased the time that the mice spent in estrus and decreased the time the mice spent in metestrus/diestrus compared to control. DiNP exposure (0.15-1500 ppm) did not significantly affect time in estrus or metestrus/diestrus compared to control. Mix exposure at 0.15 and 1500 ppm for 3 months decreased the time the mice spent in metestrus/diestrus and increased the time the mice spent in estrus compared to control. DEHP (0.15-1500 ppm) or Mix (0.15-1500 ppm) exposure did not affect fertility-related indices compared to control. However, long-term DiNP exposure at 1500 ppm significantly reduced gestational index and birth rate compared to control. These data indicate that chronic dietary exposure to phthalates alters estrous cyclicity, and long-term exposure to DiNP reduces gestational index and birth rate in mice.

In 2015, EFSA established a temporary tolerable daily intake (t-TDI) for BPA of 4 μg/kg body weight (bw) per day. In 2016, the European Commission mandated EFSA to re-evaluate the risks to public health from the presence of BPA in foodstuffs and to establish a tolerable daily intake (TDI). For this re-evaluation, a pre-established protocol was used that had undergone public consultation. The CEP Panel concluded that it is Unlikely to Very Unlikely that BPA presents a genotoxic hazard through a direct mechanism. Taking into consideration the evidence from animal data and support from human observational studies, the immune system was identified as most sensitive to BPA exposure. An effect on Th17 cells in mice was identified as the critical effect; these cells are pivotal in cellular immune mechanisms and involved in the development of inflammatory conditions, including autoimmunity and lung inflammation. A reference point (RP) of 8.2 ng/kg bw per day, expressed as human equivalent dose, was identified for the critical effect. Uncertainty analysis assessed a probability of 57-73% that the lowest estimated Benchmark Dose (BMD) for other health effects was below the RP based on Th17 cells. In view of this, the CEP Panel judged that an additional uncertainty factor (UF) of 2 was needed for establishing the TDI. Applying an overall UF of 50 to the RP, a TDI of 0.2 ng BPA/kg bw per day was established. Comparison of this TDI with the dietary exposure estimates from the 2015 EFSA opinion showed that both the mean and the 95th percentile dietary exposures in all age groups exceeded the TDI by two to three orders of magnitude. Even considering the uncertainty in the exposure assessment, the exceedance being so large, the CEP Panel concluded that there is a health concern from dietary BPA exposure.

Prenatal exposure to endocrine-disrupting chemicals has been linked to gestational hypertension (GH) and preeclampsia (PE). However, the results were conflicting and inconclusive. We conducted a systematic review and meta-analysis for an overview of these relationships. We searched PubMed, and Google Scholar for studies investigating bisphenol A, phthalates, and per or poly-fluoroalkyl substances and GH or PE. Pooled odds ratio (OR) with a 95% confidence interval (CI) were calculated for risk estimate using the generic inverse variance method. A total of 14 studies were included in the present analysis. The pooled results demonstrated that perfluorooctanoic acid (PFOA, OR:1.20, 95% CI: 1.04, 1.39), perfluoro octane sulfonic acid (PFOS, (OR:1.23, 95% CI: 1.10, 1.38), and perfluononanoic acid (PFNA, OR:1.20, 95% CI: 1.03, 1.40) were significantly associated with an increased risk of PE. There was no significant association observed with perfluoro hexane sulfonic acid (PFHxS), perfluoro decanoic acid (PFDA), perfluoro heptanoic acid (PFHpA), and perfluoro undecanoic acid (PFUnDA) and PE. For GH, a statistically significant positive association was found with PFOA (OR:1.18, 95% CI: 1.01, 1.39) and PFHxS (OR:1.15, 95% CI: 1.02, 1.29). Among various phthalates analysed only mono-ethyl phthalate (MEP, OR:1.37, 95% CI: 1.11, 1.70) showed an association with GH. From our analysis, bisphenol A exposure during pregnancy did not show a significant association with the risk of PE. Our findings indicated that exposure to PFASs such as PFOA, PFOS, and PFNA during pregnancy is associated with an increased risk of PE and PFOA and PFHxS with GH. We also found that MEP was associated with GH. Most of the results were unstable in sensitivity analysis. Since most of these associations have limited evidence, more research is needed to confirm these findings.

The epigenome plays an important role in shaping phenotypes. However, whether the environment can alter an organism's phenotype across several generations through epigenetic remodeling in the germline is still a highly debated topic. In this chapter, we briefly review the mechanisms of epigenetic inheritance and their connection with germline development before highlighting specific developmental windows of susceptibility to environmental cues. We further discuss the evidence of transgenerational inheritance to a range of different environmental cues, both epidemiological in humans and experimental in rodent models. Doing so, we pinpoint the current challenges in demonstrating transgenerational inheritance to environmental cues and offer insight in how recent technological advances may help deciphering the epigenetic mechanisms at play. Together, we draw a detailed picture of how our environment can influence our epigenomes, ultimately reshaping our phenotypes, in an extended theory of inheritance.

Similar to environmental factors, EDCs (endocrine-disrupting chemicals) can influence gene expression without modifying the DNA sequence. It is commonly accepted that the transgenerational inheritance of parentally acquired traits is conveyed by epigenetic alterations also known as "epimutations". DNA methylation, acetylation, histone modification, RNA-mediated effects and extracellular vesicle effects are the mechanisms that have been described so far to be responsible for these epimutations. They may lead to the transgenerational inheritance of diverse phenotypes in the progeny when they occur in the germ cells of an affected individual. While EDC-induced health effects have dramatically increased over the past decade, limited effects on sperm epigenetics have been described. However, there has been a gain of interest in this issue in recent years. The gametes (sperm and oocyte) represent targets for EDCs and thus a route for environmentally induced changes over several generations. This review aims at providing an overview of the epigenetic mechanisms that might be implicated in this transgenerational inheritance.

A wide range of chemicals have been identified as endocrine disrupting chemicals (EDCs) in vertebrate species. Most studies of EDCs have focused on exposure of both male and female adults to these chemicals; however, there is clear evidence that EDCs have dramatic effects when mature or developing gametes are exposed, and consequently are associated with in multigenerational and transgenerational effects. Several publications have reviewed such actions of EDCs in subgroups of species, e.g., fish or rodents. In this review, we take a holistic approach synthesizing knowledge of the effects of EDCs across vertebrate species, including fish, anurans, birds, and mammals, and discuss the potential mechanism(s) mediating such multi- and transgenerational effects. We also propose a series of recommendations aimed at moving the field forward in a structured and coherent manner.

Meiotic recombination is a critical process for sexually reproducing organisms. This exchange of genetic information between homologous chromosomes during meiosis is important not only because it generates genetic diversity, but also because it is often required for proper chromosome segregation. Consequently, the frequency and distribution of crossovers are tightly controlled to ensure fertility and offspring viability. However, in many systems, it has been shown that environmental factors can alter the frequency of crossover events. Two studies in flies and yeast point to nutritional status affecting the frequency of crossing over. However, this question remains unexplored in mammals. Here, we test how crossover frequency varies in response to diet in Mus musculus males. We use immunohistochemistry to estimate crossover frequency in multiple genotypes under two diet treatments. Our results indicate that while crossover frequency was unaffected by diet in some strains, other strains were sensitive even to small composition changes between two common laboratory chows. Therefore, recombination is both resistant and sensitive to certain dietary changes in a strain-dependent manner and, hence, this response is genetically determined. Our study is the first to report a nutrition effect on genome-wide levels of recombination. Moreover, our work highlights the importance of controlling diet in recombination studies and may point to diet as a potential source of variability among studies, which is relevant for reproducibility.

Gestational high butterfat (HFB) and/or endocrine disruptor exposure was previously found to disrupt spermatogenesis in adulthood. This study addresses the data gap in our knowledge regarding transgenerational transmission of the disruptive interaction between a high-fat diet and endocrine disruptor bisphenol A (BPA). F0 generation Sprague-Dawley rats were fed diets containing butterfat (10 kcal%) and high in butterfat (39 kcal%, HFB) with or without BPA (25 µg/kg body weight/day) during mating and pregnancy. Gestationally exposed F1-generation offspring from different litters were mated to produce F2 offspring, and similarly, F2-generation animals produced F3-generation offspring. One group of F3 male offspring was administered either testosterone plus estradiol-17β (T + E2) or sham via capsule implants from postnatal days 70 to 210. Another group was naturally aged to 18 months. Combination diets of HFB + BPA in F0 dams, but not single exposure to either, disrupted spermatogenesis in F3-generation adult males in both the T + E2-implanted group and the naturally aged group. CYP19A1 localization to the acrosome and estrogen receptor beta (ERbeta) localization to the nucleus were associated with impaired spermatogenesis. Finally, expression of methyl-CpG-binding domain-3 (MBD3) was consistently decreased in the HFB and HFB + BPA exposed F1 and F3 testes, suggesting an epigenetic component to this inheritance. However, the severe atrophy within testes present in F1 males was absent in F3 males. In conclusion, the HFB + BPA group demonstrated transgenerational inheritance of the impaired spermatogenesis phenotype, but severity was reduced in the F3 generation.

The effects of endocrine-disrupting chemicals (EDCs) on fertility and reproductive development represent a rising concern in modern societies. Although the neuroendocrine control of sexual maturation is a major target of EDCs, little is known about the potential role of the hypothalamus in puberty and ovulation disruption transmitted across generations.

We hypothesized that developmental exposure to an environmentally relevant dose of EDC mixture could induce multi- and/or transgenerational alterations of sexual maturation and maternal care in female rats through epigenetic reprograming of the hypothalamus. We investigated the transmission of a disrupted reproductive phenotype via the maternal germline or via nongenomic mechanisms involving maternal care.

Adult female Wistar rats were exposed prior to and during gestation and until the end of lactation to a mixture of the following 13 EDCs: di-n-butyl phthalate (DnBP), di(2-ethylhexyl) phthalate (DEHP), bisphenol A (BPA), vinclozolin, prochloraz, procymidone, linuron, epoxynaxole, dichlorodiphenyldichloroethylene, octyl methoxynimmate, 4-methylbenzylidene camphor (4-MBC), butylparaben, and acetaminophen. Perinatally exposed offspring (F1) were mated with unexposed males to generate germ cell (F2) and transgenerationally exposed (F3 and F4) females. Sexual maturation, maternal behavior, and hypothalamic targets of exposure were studied across generations.

Germ cell (F2) and transgenerationally (F3) EDC-exposed females, but not F1, displayed delayed pubertal onset and altered folliculogenesis. We reported a transgenerational alteration of key hypothalamic genes controlling puberty and ovulation (Kiss1, Esr1, and Oxt), and we identified the hypothalamic polycomb group of epigenetic repressors as actors of this mechanism. Furthermore, we found a multigenerational reduction of maternal behavior (F1-F3) induced by a loss in hypothalamic dopaminergic signaling. Using a cross-fostering paradigm, we identified that the reduction in maternal phenotype was normalized in EDC-exposed pups raised by unexposed dams, but no reversal of the pubertal phenotype was achieved.

Rats developmentally exposed to an EDC mixture exhibited multi- and transgenerational disruption of sexual maturation and maternal care via hypothalamic epigenetic reprogramming. These results raise concerns about the impact of EDC mixtures on future generations. https://doi.org/10.1289/EHP8795.

The widely used chemical bisphenol A (BPA) has been associated with several health effects. In recent years, many derivatives were developed to replace BPA although without thorough toxicological evaluation. Here, we employed a human embryoid body (EB)-based in vitro global differentiation and hepatic specification models, followed by RNA-seq analyses, to comprehensively study the potential developmental toxicity of six BPA replacements (BPS, BPF, BPZ, BPB, BPE, and BPAF), as compared to BPA. We found that those bisphenols may disrupt lineage commitment and lipid metabolism during early embryonic development. These effects mostly manifested via the dysregulation of HOX and APO family genes. Moreover, among the seven bisphenols analyzed, BPE seemed to have the mildest effects.

A total diet study (TDS) was conducted in France to assess the health risks related to the chemicals in food of non-breastfed children under three years of age (Infant TDS). For the first time, substances coming from food contact materials, such as bisphenol A (BPA), bisphenol A diglycidyl ether (BADGE) and its derivatives, some phthalates, and some ink photoinitiators, were targeted because of growing interest in these substances. Food samples were collected to be representative of the whole diet of non-breastfed children aged 1-36 months, and prepared as consumed prior to analysis. Dietary exposure was assessed for 705 representative children under three years of age. Generally, the substances from food contact materials were detected in few samples: 38% for BPA, 0% for BADGE and its derivatives, 0-35% for phthalates, 1.9% for benzophenone, and 0% for the other ink photoinitiators. Regarding exposure levels, the situation was deemed tolerable for BADGE and its hydrolysis products, di-isodecyl phthalate, dibutyl phthalate, butyl benzyl phthalate, bis(2-ethylhexyl) phthalate, and di-isononyl phthalate, benzophenone, and 4-methylbenzophenone. Only for BPA, the exposure levels of some children exceeded the lowest toxicological value established by the French Agency for Food, Environmental and Occupational Health & Safety at 0.083 µg.kg bw^-1.d^-1. The temporary tolerable daily intake of the European Food Safety Authority (EFSA), set at 4 µg.kg bw^-1.d^-1, was never exceeded. However, actual exposure to BPA was probably overestimated, as well as the associated risk, because the foods were sampled prior to the recent regulations banning BPA in food packaging. This study is the first worldwide to provide an estimate of infant food contamination levels and exposures of children under 3 years of age, based on a TDS approach. It therefore provides key data on the exposure of this particularly sensitive population to substances released from food contact materials, and presents useful data for studies evaluating exposure to mixtures or aggregated exposure.

In the three decades since endocrine disruption was conceptualized at the Wingspread Conference, we have witnessed the growth of this multidisciplinary field and the accumulation of evidence showing the deleterious health effects of endocrine-disrupting chemicals. It is only within the past decade that, albeit slowly, some changes regarding regulatory measures have taken place. In this Perspective, we address some historical points regarding the advent of the endocrine disruption field and the conceptual changes that endocrine disruption brought about. We also provide our personal recollection of the events triggered by our serendipitous discovery of oestrogenic activity in plastic, a founder event in the field of endocrine disruption. This recollection ends with the CLARITY study as an example of a discordance between 'science for its own sake' and 'regulatory science' and leads us to offer a perspective that could be summarized by the motto attributed to Ludwig Boltzmann: "Nothing is more practical than a good theory".

It is becoming increasingly difficult to avoid exposure to man-made endocrine disrupting chemicals (EDCs) and environmental toxicants. This escalating yet constant exposure is postulated to partially explain the concurrent decline in human fertility that has occurred over the last 50 years. Controversy however remains as to whether associations exist, with conflicting findings commonly reported for all major EDC classes. The primary aim of this extensive work was to identify and review strong peer-reviewed evidence regarding the effects of environmentally-relevant EDC concentrations on adult male and female fertility during the critical periconception period on reproductive hormone concentrations, gamete and embryo characteristics, as well as the time to pregnancy in the general population. Secondly, to ascertain whether individuals or couples diagnosed as sub-fertile exhibit higher EDC or toxicant concentrations. Lastly, to highlight where little or no data exists that prevents strong associations being identified. From the greater than 1480 known EDCs, substantial evidence supports a negative association between exposure to phthalates, PCBs, PBDEs, pyrethroids, organochloride pesticides and male fertility and fecundity. Only moderate evidence exists for a negative association between BPA, PCBs, organochloride pesticides and female fertility and fecundity. Overall fewer studies were reported in women than men, with knowledge gaps generally evident for both sexes for all the major EDC classes, as well as a paucity of female fertility studies following exposure to parabens, triclosans, dioxins, PFAS, organophosphates and pyrethroids. Generally, sub-fertile individuals or couples exhibit higher EDC concentrations, endorsing a positive association between EDC exposure and sub-fertility. This review also discusses confounding and limiting factors that hamper our understanding of EDC exposures on fertility and fecundity. Finally, it highlights future research areas, as well as government, industry and social awareness strategies required to mitigate the negative effects of EDC and environmental toxicant exposure on human fertility and fecundity.

There is increasing evidence that bisphenols BPS and BPF, which are analogues of BPA, have deleterious effects on reproduction even at extremely low doses. Indirect exposure via the maternal route (i.e. across the placenta and/or by breastfeeding) is underestimated, although it can be assumed to be a cause of idiopathic female infertility. Therefore, we hypothesised the deleterious effects of exposure to BPA analogues during breastfeeding on the ovarian and oocyte quality of offspring. A 15-day exposure period of pups was designed, whilst nursing dams (N ≥ 6 per experimental group) were treated via drinking water with a low (0.2 ng/g body weight/day) or moderate (20 ng/g body weight/day) dose of bisphenol, mimicking real exposure in humans. Thereafter, female pups were bred to 60 days and oocytes were collected. Immature oocytes were used in the in-vitro maturation assay; alternatively, in-vivo-matured oocytes were isolated and used for parthenogenetic activation. Both in-vitro- and in-vivo-matured oocytes were subjected to immunostaining of spindle microtubules (α-tubulin) and demethylation of histone H3 on the lysine K27 (H3K27me2) residue. Although very low doses of both BPS and BPF did not affect the quality of ovarian histology, spindle formation and epigenetic signs were affected. Notably, in-vitro-matured oocytes were significantly sensitive to both doses of BPS and BPF. Although no significant differences in spindle-chromatin quality were identified in ovulated and in-vivo-matured oocytes, developmental competence was significantly damaged. Taken together, our mouse model provides evidence that bisphenol analogues represent a risk to human reproduction, possibly leading to idiopathic infertility in women.

The onset of puberty and the female ovulatory cycle are important developmental milestones of the reproductive system. These processes are controlled by a tightly organized network of neurotransmitters and neuropeptides, as well as genetic, epigenetic and hormonal factors, which ultimately drive the pulsatile secretion of gonadotropin-releasing hormone. They also strongly depend on organizational processes that take place during fetal and early postnatal life. Therefore, exposure to environmental pollutants such as endocrine-disrupting chemicals (EDCs) during critical periods of development can result in altered brain development, delayed or advanced puberty and long-term reproductive consequences, such as impaired fertility. The gonads and peripheral organs are targets of EDCs, and research from the past few years suggests that the organization of the neuroendocrine control of reproduction is also sensitive to environmental cues and disruption. Among other mechanisms, EDCs interfere with the action of steroidal and non-steroidal receptors, and alter enzymatic, metabolic and epigenetic pathways during development. In this Review, we discuss the cellular and molecular consequences of perinatal exposure (mostly in rodents) to representative EDCs with a focus on the neuroendocrine control of reproduction, pubertal timing and the female ovulatory cycle.

Endocrine-disrupting chemicals (EDCs) exist ubiquitously in the environment. Epidemiological data suggest that the increasing prevalence of infertility may be related to the numerous chemicals. Exposure to EDCs may have significant adverse impacts on the reproductive system including fertility, ovarian reserve, and sex steroid hormone levels. This chapter covers the common exposure ways, the origins of EDCs, and their effects on ovarian function, follicular genesis, and oocyte quality. Furthermore, we will review the origin and the physiology of ovarian development, as well as explore the mechanisms in which EDCs act on the ovary from human and animal data. And then, we will focus on the bisphenol A (BPA), which has been shown to reduce fertility and ovarian reserve, as well as disrupt steroidogenesis in animal and human models. Finally, we will discuss the future direction of prevention and solution methods.

Bisphenol A (BPA) is an industrial plasticizer widely found in consumer products, and exposure to BPA during early development has been associated with the prevalence of various cardiometabolic diseases including obesity, metabolic syndrome, type 2 diabetes, and cardiovascular diseases. To elucidate the molecular perturbations underlying the connection of low-dose prenatal BPA exposure to cardiometabolic diseases, we conducted a multi-dimensional systems biology study assessing the liver transcriptome, gut microbial community, and diverse metabolic phenotypes in both male and female mouse offspring exposed to 5 μg/kg/day BPA during gestation. Prenatal exposure to low-dose BPA not only significantly affected liver genes involved in oxidative phosphorylation, PPAR signaling and fatty acid metabolism, but also affected the gut microbial composition in an age- and sex-dependent manner. Bacteria such as those belonging to the S24-7 and Lachnospiraceae families were correlated with offspring phenotypes, differentially expressed liver metabolic genes such as Acadl and Dgat1, and key drivers identified in our gene network modeling such as Malat1 and Apoa2. This multiomics study provides insight into the relationship between gut bacteria and host liver genes that could contribute to cardiometabolic disease risks upon low-dose BPA exposure.

Bisphenol A (BPA) can cause detrimental effects on fetal growth. However, the effects of BPA alternatives, such as bisphenol F (BPF) and bisphenol S (BPS), on fetal growth are less known.

To investigate the relationships of prenatal BPA, BPF, and BPS exposures with fetal growth parameters and gestational age.

Urinary BPA, BPF, and BPS were measured in 1,197 pregnant women before delivery in a Chinese cohort. The associations of prenatal exposure to BPA, BPF, and BPS with fetal growth parameters and gestational age were examined, and associations stratified by fetal sex were also conducted. We used a restricted cubic splines (RCS) model to examine the dose-response associations between exposures and outcomes.

Maternal urinary BPA and BPF were negatively related to birth length (-0.30 cm, 95% CI: -0.44, -0.15 and -0.21 cm, 95% CI: -0.36, -0.07 comparing the extreme exposure groups, respectively, both p for trends < 0.01). These associations were more pronounced in girls with inverted U-shaped dose-response relationships. Maternal urinary BPA and BPF were positively related to ponderal index (0.05 g/cm³ × 100, 95% CI: 0.01, 0.09 and 0.04 g/cm³ × 100, 95% CI: 0.01, 0.08 comparing the extreme exposure groups, respectively, both p for trends = 0.02), and maternal urinary BPS was associated with shorter gestational age (-0.20 weeks, 95% CI: -0.37, -0.03 comparing the extreme exposure groups, p for trend = 0.02). These associations were only observed in girls and exhibited a linear dose-response relationship.

Prenatal BPA, BPF, and BPS exposures were associated with detrimental effects on fetal growth parameters, and stronger effects were noted in female infants.

In utero Bisphenol A (BPA) exposure has been linked to many deficits during brain development, including sexual differentiation, behavior, and motor coordination. Yet, how BPA induces these disorders and whether its effects are long lasting are largely unknown. In this study, using a mouse model, we demonstrated that in utero exposure to an environmentally relevant dose of BPA induced locomotor deficits, anxiety-like behavior, and declarative memory impairments that persisted into old age (18 months). Compared to the control animals, the BPA-exposed mice had a significant decrease in locomotor activity, exploratory tendencies, and long-term memory, and an increase in anxiety. The global brain gene expression profile was altered permanently by BPA treatment and showed regional and sexual differences. The BPA-treated male mice had more changes in the hippocampus, while female mice experienced more changes in the cortex. Overall, we demonstrate that in utero exposure to BPA induces permanent changes in brain gene expression in a region-specific and sex-specific manner, including a significant decrease in locomotor activity, learning ability, long-term memory, and an increase in anxiety. Fetal/early life exposures permanently affect neurobehavioral functions that deteriorate with age; BPA exposure may compound the effects of aging.

"Consortium Linking Academic and Regulatory Insights on BPA Toxicity" (CLARITY-BPA) was a comprehensive "industry-standard" Good Laboratory Practice (GLP)-compliant 2-year chronic exposure study of bisphenol A (BPA) toxicity that was supplemented by hypothesis-driven independent investigator-initiated studies. The investigator-initiated studies were focused on integrating disease-associated, molecular, and physiological endpoints previously found by academic scientists into an industry standard guideline-compliant toxicity study. Thus, the goal of this collaboration was to provide a more comprehensive dataset upon which to base safety standards and to determine whether industry-standard tests are as sensitive and predictive as molecular and disease-associated endpoints. The goal of this report is to integrate the findings from the investigator-initiated studies into a comprehensive overview of the observed impacts of BPA across the multiple organs and systems analyzed. For each organ system, we provide the rationale for the study, an overview of methodology, and summarize major findings. We then compare the results of the CLARITY-BPA studies across organ systems with the results of previous peer-reviewed studies from independent labs. Finally, we discuss potential influences that contributed to differences between studies. Developmental exposure to BPA can lead to adverse effects in multiple organs systems, including the brain, prostate gland, urinary tract, ovary, mammary gland, and heart. As published previously, many effects were at the lowest dose tested, 2.5μg/kg /day, and many of the responses were non-monotonic. Because the low dose of BPA affected endpoints in the same animals across organs evaluated in different labs, we conclude that these are biologically - and toxicologically - relevant.

Endocrine disrupting chemicals (EDCs), such as bisphenol A (BPA) and 17α-ethinylestradiol (EE2), can have far reaching health effects, including transgenerational abnormalities in offspring that never directly contacted either chemical. We previously reported reduced fertilization rates and embryo survival at F2 and F3 generations caused by 7-day embryonic exposure (F0) to 100 μg/L BPA or 0.05 μg/L EE2 in medaka. Crossbreeding of fish in F2 generation indicated subfertility in males. To further understand the mechanisms underlying BPA or EE2-induced adult onset and transgenerational reproductive defects in males, the present study examined the expression of genes regulating the brain-pituitary-testis (BPT) axis in the same F0 and F2 generation male medaka. Embryonic exposure to BPA or EE2 led to hyperactivation of brain and pituitary genes, which are actively involved in reproduction in adulthood of the F0 generation male fish, and some of these F0 effects continued to the F2 generation (transgenerational effects). Particularly, the F2 generation inherited the hyperactivated state of expression for kisspeptin (kiss1 and kiss2) and their receptors (kiss1r and kiss2r), and gnrh and gnrh receptors. At F2 generation, expression of DNA methyltransferase 1 (dnmt1) decreased in brain of the BPA treatment lineage, while EE2 treatment lineage showed increased dnmt3bb expression. Global hypomethylation pattern was observed in the testis of both F0 and F2 generation fish. Taken together, these results demonstrated that BPA or EE2-induced transgenerational reproductive impairment in the F2 generation was associated with alterations of reproductive gene expression in brain and testis and global DNA methylation in testis.

Studying vitamin E [α-tocopherol (α-T)] metabolism and function in the brain and other tissues requires an animal model with low α-T status, such as the transgenic α-T transfer protein (Ttpa)-null (Ttpa - / -) mouse model. Ttpa + / - dams can be used to produce Ttpa - / - and Ttpa+/+ mice for these studies. However, the α-T content in Ttpa + / - dams' diet requires optimization; diets must provide sufficient α-T for reproduction, while minimizing the transfer of α-T to the offspring destined for future studies that require low baseline α-T status. The goal of this work was to assess the effectiveness and feasibility of 2 breeding diet strategies on reproduction outcomes and offspring brain α-T concentrations. These findings will help standardize the breeding methodology used to generate the Ttpa - / - mice for neurological studies.

Humans and animals are repeatedly exposed to endocrine disruptors, many of which are ubiquitous in the environment. Endocrine disruptors interfere with hormone action; thus, causing non-monotonic dose responses that are atypical of standard toxicant exposures. The female reproductive system is particularly susceptible to the effects of endocrine disruptors. Likewise, exposures to endocrine disruptors during developmental periods are particularly concerning because programming during development can be adversely impacted by hormone level changes. Subsequently, developing reproductive tissues can be predisposed to diseases in adulthood and these diseases can be passed down to future generations. The mechanisms of action by which endocrine disruptors cause disease transmission to future generations are thought to include epigenetic modifications. This review highlights the effects of endocrine disruptors on the female reproductive system, with an emphasis on the multi- and transgenerational epigenetic effects of these exposures.

The developmental origins of health and diseases (DOHaD) is a concept stating that adverse intrauterine environments contribute to the health risks of offspring. Since the theory emerged more than 30 years ago, many epidemiological and animal studies have confirmed that in utero exposure to environmental insults, including hyperglycemia and chemicals, increased the risk of developing noncommunicable diseases (NCDs). These NCDs include metabolic syndrome, type 2 diabetes, and complications such as diabetic cardiomyopathy. Studying the effects of different environmental insults on early embryo development would aid in understanding the underlying mechanisms by which these insults promote NCD development. Embryonic stem cells (ESCs) have also been utilized by researchers to study the DOHaD. ESCs have pluripotent characteristics and can be differentiated into almost every cell lineage; therefore, they are excellent in vitro models for studying early developmental events. More importantly, human ESCs (hESCs) are the best alternative to human embryos for research because of ethical concerns. In this review, we will discuss different maternal conditions associated with DOHaD, focusing on the complications of maternal diabetes. Next, we will review the differentiation protocols developed to generate different cell lineages from hESCs. Additionally, we will review how hESCs are utilized as a model for research into the DOHaD. The effects of environmental insults on hESC differentiation and the possible involvement of epigenetic regulation will be discussed.

This study was performed to examine the transgenerational effects of bisphenol (BP) A analogs, BPE, and BPS on male reproductive functions using mice as a model. CD-1 mice (F0) were orally exposed to control treatment (corn oil), BPA, BPE, or BPS (0.5 or 50 µg/kg/day) from gestational day 7 (the presence of vaginal plug = 1) to birth. Mice from F1 and F2 offspring were used to generate F3 males. Prenatal exposure to BPA, BPE, and BPS decreased sperm counts and/or motility and disrupted the progression of germ cell development as morphometric analyses exhibited an abnormal distribution of the stages of spermatogenesis in F3 males. Dysregulated serum levels of estradiol-17β and testosterone, as well as expression of steroidogenic enzymes in F3 adult testis were also observed. In the neonatal testis, although apoptosis and DNA damage were not affected, mRNA levels of DNA methyltransferases, histone methyltransferases, and their associated factors were increased by BP exposure. Furthermore, BP exposure induced immunoreactive expression of DNMT3A in Sertoli cells, strengthened DNMT3B, and weakened H3K9me2 and H3K9me3 in germ cells of the neonatal testis, whereas DNMT1, H3K4me3, and H3K27ac were not affected. In adult testis, stage-specific DNMT3B was altered by BP exposure, although DNMT3A, H3K9me2, and H3K9me3 expression remained stable. These results suggest that prenatal exposure to BPA, BPE, and BPS induces transgenerational effects on male reproductive functions probably due to altered epigenetic modification following disruption of DNMTs and histone marks in the neonatal and/or adult testis.

Lamina II, also called the substantia gelatinosa (SG) of the medullary dorsal horn (the trigeminal subnucleus caudalis, Vc), is thought to play an essential role in the control of orofacial nociception because it receives the nociceptive signals from primary afferents, including thin myelinated Aδ- and unmyelinated C-fibers. Glycine, the main inhibitory neurotransmitter in the central nervous system, plays an essential role in the transference of nociceptive messages from the periphery to higher brain regions. Bisphenol A (BPA) is reported to alter the morphological and functional characteristics of neuronal cells and to be an effector of a great number of ion channels in the central nervous system. However, the electrophysiological effects of BPA on the glycine receptors of SG neurons in the Vc have not been well studied. Therefore, in this study, we used the whole-cell patch-clamp technique to determine the effect of BPA on the glycine response in SG neurons of the Vc in male mice. We demonstrated that in early neonatal mice (0-3 postnatal day mice), BPA did not affect the glycine-induced inward current. However, in the juvenile and adult groups, BPA enhanced the glycine-mediated responses. Heteromeric glycine receptors were involved in the modulation by BPA. The interaction between BPA and glycine appears to have a significant role in regulating transmission in the nociceptive pathway.

This paper deals with the effect of photobiomodulation (PBM) on Daphnia magna S. and their sensitivity to cadmium sulfate, a known high toxic pollutant. In a first series of experiments, the effect of different He-Ne laser fluences irradiation (range 0.9-4300 mJ cm^-2 ) on the fertility of both parent and filial generations (F1-F3) of the crustacean was studied. It was found that PBM in some cases significantly influenced the fertility of both irradiated crustaceans and their nonirradiated offspring. By selecting two fluences (9 ± 2 mJ cm^-2 reducing fertility and 4.3 ± 0.9 J cm^-2 increasing it), the effect of these on toxicity of cadmium sulfate was evaluated. These experiments have shown that prior irradiation with low-intensity light of a helium-neon laser with 632.8 nm wavelength can change the sensitivity of aquatic organisms to toxin cadmium sulfate. The degree and direction of changes depend on the toxicant concentration and the irradiation dose.

Bisphenol A (BPA) is an abundant environmental contaminant and studies have shown the presence of BPA in the urine of over 90% of population tested in Canada and USA. In addition to its reported harmful effects, there is concern for its transgenerational effects. For a compound to induce transgenerational effect, an epigenetic mark should be mitotically and meiotically stable without reprogramming in primordial germ cells and post fertilization embryos. In the present study, female zebrafish were treated with an environmental dose (20 μg/L) of BPA and then crossed with untreated males. To assess epigenetic effects, transcript levels of several genes involved in female reproduction were measured in adult and in 24 hpf embryos up to F3 generation. Exposure to BPA affected adult female fertility up to F2 generation. In F0, F1 and F2 ovaries transcript levels for several genes involved in reproduction, including esr, star, lhcgr and fshr were affected. To investigate epigenetic mechanisms of gene expression modulation, we studied promoter DNA methylation. Among genes involved in gonadal differentiation, amh transcript level was reduced in 24 hpf embryos, up to the F3 generation. Variation in amh transcript level was associated with hyper-methylation of its promoter and changes in H3K4me3/H3K27me3 enrichment, coherent with gene silencing. The findings provide evidence for transgenerational effects of BPA in zebrafish and demonstrate that amh is susceptible to stable epigenetic alterations. CAPSULE: Transgenerational effects of BPA on female reproductive physiology.

Age at female puberty is associated with adult morbidities, including breast cancer and diabetes. Hormonally active chemicals are suspected of altering pubertal timing. We examined whether persistent organic pollutants (POPs) are associated with age at menarche in a longitudinal study.

We analyzed data for females enrolled at age 6-8 years in the Breast Cancer and Environment Research Program from California and Ohio. Participants were followed annually 2004-2013 and provided serum (mean age 7.8 years) for measurement of polychlorinated biphenyl (PCB), organochlorine pesticide (OCP), and polybrominated diphenyl ether (PBDE) concentrations. Age of menarche was assigned based on parental and participant reported dates and ages of menarche. Adjusted hazard ratios (aHRs) for menarchal onset were calculated with Cox proportional regression. Body mass index (BMI), potentially on the causal pathway, was added to parallel analyses.

Age of menarche was later with higher summed PCB levels (median 11.9 years in quartile 1 [Q1] versus 12.7 in quartile 4 [Q4]) and OCP levels (12.1 years versus 12.4, respectively). When adjusting for all covariates except BMI, higher POP concentrations were associated with later age at menarche (Q4 versus Q1 aHRs: PBDEs 0.75 [95% CI 0.58, 0.97], PCBs 0.67 [95% CI 0.5, 0.89], and OCPs 0.66 [95% CI 0.50, 0.89]). Additional adjustment for BMI attenuated aHRs; PCB aHR approached the null.

Findings revealed later onset of menarche with higher concentrations of certain POPs, possibly through an association with BMI. Altered pubertal timing may have long lasting effects on reproductive health and disease risk, so continued attention is important for understanding the biological processes affected by hormonally active chemicals.