Review on bisphenol A and the risk of polycystic ovarian syndrome: an insight from endocrine and gene expression

Connecting Bisphenol A Exposure to PCOS: Findings from a Case-Control Investigation

Polycystic Ovary Syndrome (PCOS) is a multifaceted condition influenced by genetic, hormonal, and environmental factors. Among environmental factors, Bisphenol A (BPA)-a recognized endocrine disruptor-has been implicated in the development of PCOS. The study aimed to compare BPA levels in women diagnosed with PCOS with those in healthy controls, using the high-performance liquid chromatography (HPLC) technique. The study involved 80 women diagnosed with PCOS and 50 healthy control participants. Demographic and biochemical parameters were recorded, including age, Body Mass Index (BMI), and levels of testosterone, estradiol, Luteinizing Hormone (LH), Follicle Stimulating Hormone (FSH), Prolactin (PRL), Dehydroepiandrosterone Sulfate (DHEA-S), Thyroid Stimulating Hormone (TSH), and Insulin Resistance as measured by the Homeostatic Model Assessment (HOMA-IR). Furthermore, BPA levels were measured using the HPLC technique. Women with PCOS exhibited significantly higher mean age and BMI compared to healthy controls (p = 0.01, p < 0.0001, respectively). Additionally, higher levels of testosterone (p = 0.04), LH (p = 0.03) and BPA (p < 0.0001) were observed in women with PCOS. However, estradiol, FSH, PRL, LH/FSH ratio, DHEA-S, and TSH levels were not significantly different between the two groups. HOMA-IR levels were not recorded for the control group. A notable positive relationship emerged between Bisphenol A and luteinizing hormone (LH) levels (r = 0.23, p = 0.03), also significant negative correlation appeared between Bisphenol A and thyroid-stimulating hormone (TSH) levels. This study found that women with PCOS have elevated BPA levels compared with healthy controls, showing a need for further research on the relationship between BPA exposure and the development of PCOS.

Low-Temperature Methanolysis of Polycarbonate over Solid Base Sodium Aluminate

Herein, a low-cost and readily available sodium aluminate (NaAlO2) was used as a solid base catalyst for the depolymerization of polycarbonate (PC) via methanolysis in the presence of tetrahydrofuran (THF) as a solvent. NaAlO2 was highly active for the reaction, and the performance was comparable to that of soluble strong base SrO and much higher than those of MgO and CaO. By the reaction over the catalyst, a highly pure and crystalline bisphenol A (BPA) was obtained. Among tested organic solvents, THF was the best in aiding PC methanolysis over NaAlO2 due to the polarity similar to PC according to Hansen solubility parameters (HSPs). At 60 °C, 98.1% PC conversion and 96.8% BPA yield were achieved within just 2 h. NaAlO2 was reusable without any severe catalyst deactivation in at least four runs. The mechanistic study revealed that the reaction proceeded via the methoxide pathway, with THF aiding the dissolution of PC. The reaction over NaAlO2 possessed a low apparent activation energy (Ea) of 75.1 kJ mol-1, which is the lowest ever reported so far for the reaction over solid catalysts.

Genetic and Epigenetic Profiles of Polycystic Ovarian Syndrome and In Vitro Bisphenol Exposure in a Human Granulosa Cell Model

Higher levels of bisphenols are found in granulosa cells of women with polycystic ovary syndrome (PCOS), posing the question: Is bisphenol exposure linked to PCOS pathophysiology? Human granulosa cells were obtained from women with and without PCOS, and genes and microRNAs associated with PCOS were investigated. The first phase compared healthy women and those with PCOS, revealing distinct patterns: PCOS subjects had lower 11β-HSD1 (p = 0.0217) and CYP11A1 (p = 0.0114) levels and elevated miR-21 expression (p = 0.02535), elucidating the molecular landscape of PCOS, and emphasizing key players in its pathogenesis. The second phase focused on healthy women, examining the impact of bisphenols (BPA, BPS, BPF) on the same genes. Results revealed alterations in gene expression profiles, with BPS exposure increasing 11β-HSD1 (p = 0.02821) and miR-21 (p = 0.01515) expression, with the latest mirroring patterns in women with PCOS. BPA exposure led to elevated androgen receptor (AR) expression (p = 0.0298), while BPF exposure was associated with higher levels of miR-155. Of particular interest was the parallel epigenetic expression profile between BPS and PCOS, suggesting a potential link. These results contribute valuable insights into the nuanced impact of bisphenol exposure on granulosa cell genes, allowing the study to speculate potential shared mechanisms with the pathophysiology of PCOS.

The adverse role of endocrine disrupting chemicals in the reproductive system

Reproductive system diseases pose prominent threats to human physical and mental well-being. Besides being influenced by genetic material regulation and changes in lifestyle, the occurrence of these diseases is closely connected to exposure to harmful substances in the environment. Endocrine disrupting chemicals (EDCs), characterized by hormone-like effects, have a wide range of influences on the reproductive system. EDCs are ubiquitous in the natural environment and are present in a wide range of industrial and everyday products. Currently, thousands of chemicals have been reported to exhibit endocrine effects, and this number is likely to increase as the testing for potential EDCs has not been consistently required, and obtaining data has been limited, partly due to the long latency of many diseases. The ability to avoid exposure to EDCs, especially those of artificially synthesized origin, is increasingly challenging. While EDCs can be divided into persistent and non-persistent depending on their degree of degradation, due to the recent uptick in research studies in this area, we have chosen to focus on the research pertaining to the detrimental effects on reproductive health of exposure to several EDCs that are widely encountered in daily life over the past six years, specifically bisphenol A (BPA), phthalates (PAEs), polychlorinated biphenyls (PCBs), parabens, pesticides, heavy metals, and so on. By focusing on the impact of EDCs on the hypothalamic-pituitary-gonadal (HPG) axis, which leads to the occurrence and development of reproductive system diseases, this review aims to provide new insights into the molecular mechanisms of EDCs' damage to human health and to encourage further in-depth research to clarify the potentially harmful effects of EDC exposure through various other mechanisms. Ultimately, it offers a scientific basis to enhance EDCs risk management, an endeavor of significant scientific and societal importance for safeguarding reproductive health.

Emerging pollutants in etiology and pathophysiology of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a multifactorial endocrine disorder affecting reproductive-aged women worldwide. Although genetic and lifestyle factors have been implicated in its etiology, emerging evidence suggests that exposure to environmental pollutants may also contribute significantly to the development and pathophysiology of PCOS. This review article aims to provide a comprehensive overview of the potential role of emerging pollutants, including pharmaceuticals and personal care products (PPCPs), microplastics, endocrine disruptors, and nanoparticles, in PCOS development. The article summarizes the current understanding of PCOS pathogenesis and its clinical manifestations. Subsequently, it delves into the mechanisms of action of the emerging pollutants, exploring how they may disrupt the endocrine system, interfere with hormonal regulation, and contribute to the manifestation of PCOS symptoms. Moreover, the potential for cumulative effects and synergistic interactions between these pollutants demands a cautious approach when considering their role in PCOS etiology.

Liver and ovarian toxicities boosted by bisphenol and gamma radiation in female albino rats

Bisphenol A (BPA), a carbon-based synthetic polymer compound, was newly classified as an environmental toxicant and an endocrine-disrupting chemical leading to abnormalities in cell proliferation, apoptosis, or migration that contributes to cancer development and progression. This study aims to evaluate the effect of the elevation of γ- radiation dose and BPA on the liver and ovaries of female rats. In this study, eighty female albino rats (130-150 g) were used in this work. Rats in this experiment received BPA in ethanol (50 mg/kg b. wt.) for 30 days, day after day, and in the irradiated groups, animals were administered BPA and then exposed to γ- radiation in doses (2, 4, and 6 Gy) one shot dose. Several members of the cytochrome family were examined. Exposure to γ-radiation and BPA showed an increase in cytochrome P450 and b5 fold change. Further, BPA and γ-radiation activate α and β estrogen receptors and also downregulate aromatase (CYT19) fold change. The current results also revealed that BPA and/or γ-radiation regulate the protein expression of the PI3K/Akt signaling pathway. The steroidogenic acute regulatory protein (StAR) appeared to be targeted by BPA and γ-radiation and its relative expression was elevated significantly by raising the γ-radiation dose. In conclusion, exposure to BPA, an endocrine-disrupting chemical, leads to marked toxicity. Additionally, toxicity is heightened by increasing the γ-radiation dose, either alone or in combination with BPA.

Nontargeted Analysis Reveals a Broad Range of Bioactive Pollutants in Drinking Water by Estrogen Receptor Affinity-Mass Spectrometry

Exposure to environmental endocrine-disrupting chemicals (EDCs) can cause extensive health issues. However, specific EDCs remain elusive. This work aimed at performing nontargeted identification of estrogen receptor α (ERα)-active compounds using an ERα protein affinity assay combined with high-resolution mass spectrometry in the source and drinking water sampled from major rivers in China. Fifty-one potential ERα-active compounds across 13 categories were identified. For the first time, diisodecyl phenyl phosphate was found to have antiestrogenic activity, and three chemicals (galaxolidone, bensulfuron methyl, and UV234) were plausible ERα ligands. Among the 51 identified compounds, 12 were detected in the aquatic environment for the first time, and the concentration of N-phenyl-2-naphthylamine, a widely used antioxidant in rubber products, was up to 1469 and 1190 ng/L in source and drinking water, respectively. This study demonstrated the widespread presence of known and unknown ERα estrogenic and antiestrogenic pollutants in the major rivers that serve as key sources of drinking water in China and the low removal efficiency of these chemicals in drinking water treatment plants.

Does bisphenol A (BPA) participates in the pathogenesis of Polycystic Ovary Syndrome (PCOS)?

PCOS is an endocrine disorder characterized by chronic anovulation, hyperandrogenism, and polycystic ovaries. Its etiology is uncertain. It is debated whether BPA would be a component of the environmental factor in the etiology of PCOS. Contamination by BPA can occur from food packaging (exposure during the diet) and through skin absorption and/or inhalation. It can be transferred to the fetus via the placenta or to the infant via breast milk, and it can be found in follicular fluid, fetal serum, and amniotic fluid. The phenolic structure of BPA allows it to interact with Estrogen Receptors (ERs) through genomic signaling, in which BPA binds to nuclear ERα or Erβ, or through nongenomic signaling by binding to membrane ERs, prompting a rapid and intense response. With daily and constant exposure, BPA's tendency to bioaccumulate and its ability to activate nongenomic signaling pathways can alter women's metabolic and reproductive function, leading to hyperandrogenism, insulin resistance, obesity, atherogenic dyslipidemia, chronic inflammatory state, and anovulation and favoring PCOS. The harmful changes caused by BPA can be passed on to future generations without the need for additional exposure because of epigenetic modifications. Not only high BPA levels can produce harmful effects, but at low levels, BPA may be harmful when exposure occurs during the most vulnerable periods, such as the fetal and neonatal periods, as well as during the prepubertal age causing an early accumulation of BPA in the body. Learning how BPA participates in the pathogenesis of PCOS poses a challenge and further studies should be conducted.

Bisphenol S dysregulates thyroid hormone homeostasis; Testicular survival, redox and metabolic status: Ameliorative actions of melatonin

Bisphenol S (BPS) is an incipient threat for reproductive health augmenting societal burden of infertility worldwide. In the present study, we investigated the mechanism of BPS induced testicular dysfunctions and protective actions of melatonin in mice. BPS (150 mg/kg BW) treatment reduced serum T3/T4, testosterone and elevated insulin levels along with adverse effect on thyroid and testicular histoarchitecture. Further, BPS treatment compromised sperm quality, reduced mRNA expression of steroidogenic (StAR/CYP11A1) markers, elevated oxidative load and disrupts metabolic status. However, melatonin (5 mg/kg BW) administration to BPS treated mice showed improved hormonal/histological parameters, enhanced thyroid hormone (TR-α/Dio-2)/melatonin (MT-1) receptor expressions. Further, melatonin treatment modulated the expression of testicular survival/redox (SIRT1/PGC-1α/FOXO-1, Nrf2/HO-1, p-JAK2/p-STAT3), proliferative (PCNA) and metabolic (IR/pAKT/GLUT-1) markers. Furthermore, melatonin treatment enhanced testicular antioxidant status and reduced caspase-3 expression. In conclusion, our results showed that BPS induces endocrine/oxidative and metabolic anomalies while melatonin improved male reproductive health.

Modulation of fetoplacental growth, development and reproductive function by endocrine disrupters

Maternal endocrine homeostasis is vital to a successful pregnancy, regulated by several hormones such as human chorionic gonadotropin, estrogen, leptin, glucocorticoid, insulin, prostaglandin, and others. Endocrine stress during pregnancy can modulate nutrient availability from mother to fetus, alter fetoplacental growth and reproductive functions. Endocrine disrupters such as bisphenols (BPs) and phthalates are exposed in our daily life's highest volume. Therefore, they are extensively scrutinized for their effects on metabolism, steroidogenesis, insulin signaling, and inflammation involving obesity, diabetes, and the reproductive system. BPs have their structural similarity to 17-β estradiol and their ability to bind as an agonist or antagonist to estrogen receptors to elicit an adverse response to the function of the endocrine and reproductive system. While adults can negate the adverse effects of these endocrine-disrupting chemicals (EDCs), fetuses do not equip themselves with enzymatic machinery to catabolize their conjugates. Therefore, EDC exposure makes the fetoplacental developmental window vulnerable to programming in utero. On the one hand prenatal BPs and phthalates exposure can impair the structure and function of the ovary and uterus, resulting in placental vascular defects, inappropriate placental expression of angiogenic growth factors due to altered hypothalamic response, expression of nutrient transporters, and epigenetic changes associated with maternal endocrine stress. On the other, their exposure during pregnancy can affect the offspring's metabolic, endocrine and reproductive functions by altering fetoplacental programming. This review highlights the latest development in maternal metabolic and endocrine modulations from exposure to estrogenic mimic chemicals on subcellular and transgenerational changes in placental development and its effects on fetal growth, size, and metabolic & reproductive functions.

Bisphenol A interferes with lncRNA Fhadlos2 and RUNX3 association in adolescent mouse ovary

Bisphenol A (BPA) has a number of adverse effects on the reproductive development of females. In particular, the mechanism of disruption of ovarian development in adolescent mice is still unclear. Based on transcriptome sequencing results, a differentially expressed lncRNA, Fhad1os2, was detected in the ovaries of BPA-exposed pubertal mice. In our study, the lncRNA Fhad1os2, localized in the ovarian granulosa cell cytoplasm, could regulate the proliferation of mouse ovarian granulosa cells. Mechanistically, the results of RNA pull-down experiments as well as mass spectrometry analysis showed that ERα, an interfering signaling molecule of BPA, could directly bind lncRNA Fhad1os2 and decrease the transcription of lncRNA Fhad1os2 in response to the estrogen-like effect of BPA. BPA exposure also caused abnormal lncRNA Fhad1os2 pulldown protein-related signaling pathways in the ovaries of adolescent mice. Furthermore, lncRNA Fhad1os2 interacted with RUNX3, a transcription factor related to follicle development and hormone synthesis. As a negative regulator, lncRNA Fhad1os2 transactivated the expression of Runx3, which in turn induced RUNX3 to positively regulate aromatase (Cyp19a1) expression in mouse ovarian granulosa cells and promote estrogen synthesis. In conclusion, our study indicates that BPA exposure interferes with ERα-regulated lncRNA Fhad1os2 interactions with RUNX3 in pubertal mice, affecting estrogen synthesis in mouse granulosa cells and contributing to premature ovarian maturation in pubertal mice.

Distinct metabolic signatures in blood plasma of bisphenol A-exposed women with polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) is a complicated endocrinopathy with an unclear etiology that afflicts fertility status in women. Although the underlying causes and pathophysiology of PCOS are not completely understood, it is suspected to be driven by environmental factors as well as genetic and epigenetic factors. Bisphenol A (BPA) is a weak estrogenic endocrine disruptor known to cause adverse reproductive outcomes in women. A growing relevance supports the notion that BPA may contribute to PCOS pathogenesis. Due to the indeterminate molecular mechanisms of BPA in PCOS endocrinopathy, we sought liquid chromatography with tandem mass spectrometry (LC-MS/MS), a metabolomics strategy that could generate a metabolic signature based on urinary BPA levels of PCOS and healthy individuals. Towards this, we examined urinary BPA levels in PCOS and healthy women by ELISA and performed univariate and chemometric analysis to distinguish metabolic patterns among high and low BPA in PCOS and healthy females, followed by pathway and biomarker analysis employing MetaboAnalyst 5.0. Our findings indicated aberrant levels of certain steroids, sphingolipids, and others, implying considerable disturbances in steroid hormone biosynthesis, linoleic, linolenic, sphingolipid metabolism, and various other pathways across target groups in comparison to healthy women with low BPA levels. Collectively, our findings provide insight into metabolic signatures of BPA-exposed PCOS women, which can potentially improve management strategies and precision medicine.

Acute/chronic exposure to bisphenol A induced immunotoxicity in zebrafish and its potential association with pancreatic cancer risk

Previous studies have confirmed that bisphenol A (BPA) induced immune toxicity and affected diseases, however, the underlying mechanism remains unknown. In the present study, zebrafish was employed as the model to assess the immunotoxicity and the potential disease risk of BPA exposure. Upon BPA exposure, a series of abnormalities were found, which included the increased oxidative stress, damaged innate and adaptive immune functions and the elevated insulin and blood glucose levels. According to the target prediction and RNA sequencing data of BPA, the differential expression genes were found enriched in immune- and pancreatic cancer-related pathway and process, and the potential role of stat3 in the regulation of these processes was revealed. The key immune- and pancreatic cancer-related genes were selected for further confirmation by RT-qPCR. Based on the changes in the expression levels of these genes, our hypothesis that BPA induced the occurrence of pancreatic cancer by modulating immune responses was further evidenced. Deeper mechanism was further disclosed by molecular dock simulation and survival analysis of key genes, proving that BPA stably bound to STAT3 and IL10 and STAT3 may serve as the target of BPA-inducing pancreatic cancer. These results are of great significance in deepening the molecular mechanism of immunotoxicity induced by BPA and our understanding of the risk assessment of contaminants.

Continuous light exposure influences luteinization and luteal function of ovary in ICR mice

With the rapid change of people's lifestyle, more childbearing couples live with irregular schedules (i.e., staying up late) and suffer from decreased fertility and abortion, which can be caused by luteal phase defect (LPD). We used continuous light-exposed mice as a model to observe whether continuous light exposure may affect luteinization and luteal function. We showed that the level of progesterone in serum reduced (p < .001), the number of corpus luteum (CL) decreased (p < .01), and the expressions of luteinization-related genes (Lhcgr, Star, Ptgfr, and Runx2), clock genes (Clock and Per1), and Mt1 were downregulated (p < .05) in the ovaries of mice exposed to continuous light, suggesting that continuous light exposure induces defects in luteinization and luteal functions. Strikingly, injection of melatonin (3 mg/kg) could improve luteal functions in continuous light-exposed mice. Moreover, we found that, after 2 h of hCG injection, the level of pERK1/2 in the ovary decreased in the continuous light group, but increased in the melatonin administration group, suggesting that melatonin can improve LPD caused by continuous light exposure through activating the ERK1/2 pathway. In summary, our data demonstrate that continuous light exposure affects ovary luteinization and luteal function, which can be rescued by melatonin.

Cumulus Cell Transcriptome after Cumulus-Oocyte Complex Exposure to Nanomolar Cadmium in an In Vitro Animal Model of Prepubertal and Adult Age

Cadmium (Cd), a highly toxic pollutant, impairs oocyte fertilization, through oxidative damage on cumulus cells (CCs). This study analysed the transcriptomic profile of CCs of cumulus-oocyte complexes (COCs) from adult and prepubertal sheep, exposed to Cd nanomolar concentration during in vitro maturation. In both age-groups, CCs of matured oocytes underwent RNA-seq, data analysis and validation. Differentially expressed genes (DEGs) were identified in adult (n = 99 DEGs) and prepubertal (n = 18 DEGs) CCs upon Cd exposure. Transcriptomes of adult CCs clustered separately between Cd-exposed and control samples, whereas prepubertal ones did not as observed by Principal Component Analysis. The transcriptomic signature of Cd-induced CC toxicity was identified by gene annotation and literature search. Genes associated with previous studies on ovarian functions and/or Cd effects were confirmed and new genes were identified, thus implementing the knowledge on their involvement in such processes. Enrichment and validation analysis showed that, in adult CCs, Cd acted as endocrine disruptor on DEGs involved in hormone biosynthesis, cumulus expansion, regulation of cell signalling, growth and differentiation and oocyte maturation, whereas in prepubertal CCs, Cd affected DEGs involved in CC development and viability and CC-oocyte communications. In conclusion, these DEGs could be used as valuable non-invasive biomarkers for oocyte competence.

Bisphenol A and its substitutes in the aquatic environment: Occurrence and toxicity assessment

Bisphenol A is classified as a high production volume chemical commonly used in the manufacture of polycarbonate plastics, epoxy resins and thermal paper. The endocrine disrupting properties of this xenobiotic have led to the restriction and prohibition of its use in many consumer products. To date, many chemical compounds with a chemical structure similar to bisphenol A have been used in consumer products as its replacement. The ubiquitous occurrence of bisphenol A and its substitutes in the environment and their endocrine activity as well as adverse effects on aquatic organisms is a global concern, especially because many available literature reports show that many substitutes (e.g. bisphenol AF, bisphenol AP, bisphenol B, bisphenol C, bisphenol F, bisphenol G, bisphenol FL, tetrabromobisphenol A) exert adverse effects on aquatic organisms, similar to, or even stronger than bisphenol A. Therefore, the objective of this paper is to provide a comprehensive overview of the production, sources, occurrence and associated toxicity, as well as the endocrine activity of bisphenol A and its substitutes on aquatic species. The environmental levels and ecotoxicological data presented in this review allowed for a preliminary assessment and prediction of the risk of bisphenol A and its substitutes for aquatic organisms. Furthermore, the data collected in this paper highlight that several compounds applied in bisphenol A-free products are not safe alternatives and regulations regarding their use should be introduced.

Assessment of BPA and BPS exposure in the general population in Guangzhou, China - Estimation of daily intakes based on urinary metabolites

Human exposure to bisphenol A (BPA) and bisphenol S (BPS) has garnered considerable global health concerns. In this paper, the daily intake (DI) of BPA and BPS in the general population of Guangzhou, China, were back-calculated using the biomarkers BPA glucuronides (BPA-G) and BPS glucuronides (BPS-G), respectively. The biomarkers are preferable to total BPA and BPS measurements because they are not susceptible to external contamination. A total of 1440 urine samples were gathered from the general population in Guangzhou, China, which were classified by age and sex into 36 pooled urine samples. 100% and 98% of pooled urine samples contained BPA-G and BPS-G at median values of 1.57 and 0.38 ng/mL, respectively. Based on urinary BPA-G and BPS-G concentrations, we determined the median DI of BPA and BPS to be 31.07 and 7.37 ng/(kg bw*d), respectively, and the highest values to be 106.77 ng/(kg bw*d) and 18.19 ng/(kg bw*d), respectively. Furthermore, our results showed that for the entire dataset, the DI of BPA and BPS were considerably greater in males than in females (p < 0.01)and declined significantly with age (p < 0.05). For risk assessment, the estimated DIs of BPA and BPS were much lower than the European Food Safety Authority^' s (EFSA) the temporary acceptable reference dose of 4 μg/(kg bw*d) advised for BPA, suggesting that the exposure risk of BPA and BPS for Guangzhou population is within a controllable safety range. This is the first study to investigate BPA and BPS exposure in the general population of Guangzhou, China, on the basis of urinary metabolites.

Bisphenol-A and Female Fertility: An Update of Existing Epidemiological Studies

Humans interfere with a variety of endocrine disruptors on a daily basis, which may result in adverse health effects. Among them, Bisphenol-A (BPA) is the most debated endocrine disruptor, despite being widely studied, regarding its effects on fertility. The aim of this review was to investigate the interrelation of BPA and female fertility. PubMed (Medline) was searched from 2013 until 2022 to identify epidemiological studies that report the association of BPA with fertility parameters, in vitro fertilization (IVF) outcomes, polycystic ovarian syndrome (PCOS) and endometriosis. Regarding general fertility, most studies report an inverse association between BPA and ovarian reserve markers, namely antral follicle count (AFC) and anti-Müllerian hormone (AMH). The BPA and estradiol (E2) levels did not correlate significantly in the majority of studies. No definite conclusions can be reached regarding BPA and IVF endpoints or endometriosis. Lastly, most studies report higher prevalence of PCOS in women with higher BPA concentrations, although no casualty has been proven. Although most studies fail to reach definite conclusion regarding the impact of BPA on fertility, there is accumulating evidence suggesting a negative role of BPA in female reproductive health.

Bisphenol A exposure modulates reproductive and endocrine system, mitochondrial function and cellular senescence in female adult rats: A hallmarks of polycystic ovarian syndrome phenotype

Bisphenol A (BPA) mimics estrogen and consequently suspected to be detrimental to female reproductive system. Biomonitoring confirms the BPA burden in body leading to a complex condition called polycystic ovarian syndrome (PCOS) which is frequently attributed to female infertility. Due to unclear precise molecular pathomechanisms of BPA in PCOS, we intend to examine the molecular mechanisms of the reproductive, endocrine, mitochondrial features, and cellular senescence in BPA-treated rats. We analyzed vaginal smears and ovarian follicles using microscope, assessed sex hormones by ELISA, analyzed BPA target gene expression by semi-quantitative RT-PCR, assessed senescence induction by β-galactosidase staining and immunofluorescence in BPA-treated rats. Our data showed hormonal imbalance, impaired folliculogenesis, abnormal expression patterns of target genes, CDKN2A overexpression and enhanced ROS levels in BPA-treated rats. This study provides insights on the effects of BPA exposure on ovulatory, hormonal, mitochondrial dysfunction, and senescence that benefit in better understanding of PCOS induced by BPA.

Bisphenol A analogues in associations with serum hormone levels among reproductive-aged Chinese men

BACKGROUND

Bisphenol A (BPA) as an endocrine disrupting chemical has been shown to alter reproductive endocrine function, but little is known on its analogues such as bisphenol F (BPF) and bisphenol S (BPS) with increasing usage and exposure.

OBJECTIVE

To explore the associations between exposures to BPA, BPF and BPS and serum reproductive hormones among reproductive-aged Chinese men.

METHODS

We measured BPA, BPF and BPS concentrations in repeated urine samples and multiple reproductive hormones in the serum samples collected from 462 men attending an infertility clinic in Wuhan, China. Linear regression models were applied to assess the associations between averaged urinary BPA, BPF and BPS levels and serum hormone concentrations, and restricted cubic spline (RCS) models were further utilized to explore potential non-linear associations. We also examined potential modifying effects by age and body mass index (BMI).

RESULTS

There was little evidence of associations between BPA exposure and altered reproductive hormones. However, we found that elevated BPF and BPS exposures were in negative associations with estrogen (E2) levels and E2/T (total testosterone) ratio (all P for trends < 0.05), and that elevated BPS exposure was negatively associated with SHBG levels (P for trend = 0.09). Based on the RCS models, these linear negative associations except that between BPS exposure and E2/T ratio were further confirmed. In stratified analyses, BPF and BPS exposures in relation to reduced E2 and E2/T ratio were more pronounced among men aged > 30 years, whereas their associations with reduced SHBG levels were more pronounced among men aged ≤ 30. Also, BPS exposure in negative association with FSH only emerged among men with BMI ≥ 24 kg/m² (P for interaction = 0.03).

CONCLUSION

BPF and BPS exposures were negatively associated with male serum E2, E2/T ratio and SHBG levels, and these associations varied by age and BMI.