Identification of the Bisphenol A (BPA) and the Two Analogues BPS and BPF in Cryptorchidism

High seminal BPA in IVF patients correlates with lower sperm count and up-regulated miR-21 and miR-130a

Bisphenol A (BPA) is a widespread industrial chemical, used as the key monomer of polycarbonate plastics and epoxy resins. BPA has been detected in human seminal fluid and has been correlated with changes in sperm parameters, crucial in determining male fertility. In this study, semen samples were collected from 100 patients aged 29-47 years undergoing fertility assessment between 2021 and 2023 and analyzed according to WHO guidelines. BPA levels in the seminal plasma were then measured through an enzyme-linked immunosorbent assay (ELISA) and compared to sperm quality metrics. The relative mRNA/miRNA expression of key genes associated to male reproduction, including androgen receptor, miR-34c, miR-21, miR-130a, was then quantified and compared between groups with high or low BPA content. Our results revealed that BPA levels were increased with age and were negatively correlated with sperm counts (p<0.05). The negative correlation remained significant when patients were age-matched. No other relationships between seminal BPA and motility, morphology or DNA fragmentation levels were observed. qPCR analysis showed that androgen receptor mRNA expression was significantly greater in sperm with high seminal BPA (p<0.05). Moreover, we found that the expression of miR-21 and miR-130a was also upregulated in the higher BPA group (p<0.05). These results display a relationship between BPA content in the semen and male fertility parameters, and provide insights into the molecular mechanisms through which BPA may be affecting male reproductive capability. Ultimately, this research can potentially drive changes to guidelines and exposure limits for BPA exposure.

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.

Effects of prenatal bisphenol S and bisphenol F exposure on behavior of offspring mice

Bisphenol A (BPA) is a representative endocrine-disrupting chemical that exhibits hormonal disturbance reactions. Various alternatives, such as Bisphenol S (BPS) and Bisphenol F (BPF), are being developed. BPS and BPF (which are representative alternatives to BPA) are used in consumer products such as polycarbonate plastics and epoxy resins. They have structures similar to those of BPA and have also been proven to be exogenous endocrine disruptors. However, although there are many studies on BPA, there are few studies on the neurodevelopmental effects of BPS and BPF. Therefore, in this study, we analyzed neurobehavioral changes in offspring mice exposed to BPS and BPF during brain development by administering BPS and BPF to pregnant mice. We found that prenatal exposure to BPS and BPF did not affect anxiety-and depression-like behaviors, locomotion, sociability, memory, or cognition functions in offspring mice. However, exposure to BPS and BPF decreased the preference for social novelty in the offspring mice. Taken together, these findings suggest that perinatal exposure to BPS and BPF affects changes in social behaviors, but not other behavioral changes such as emotion, memory, or cognition in the offspring mice.

Endocrine disrupting chemicals and male fertility: from physiological to molecular effects

The deleterious effects of chemical or non-chemical endocrine disruptors (EDs) on male fertility potential is well documented but still not fully elucidated. For example, the detection of industrial chemicals' metabolites in seminal plasma and follicular fluid can affect efficiency of the gametogenesis, the maturation and competency of gametes and has guided scientists to hypothesize that endocrine disrupting chemicals (EDCs) may disrupt hormonal homoeostasis by leading to a wide range of hormonal control impairments. The effects of EDCs exposure on reproductive health are highly dependent on factors including the type of EDCs, the duration of exposure, individual susceptibility, and the presence of other co-factors. Research and scientists continue to study these complex interactions. The aim of this review is to summarize the literature to better understand the potential reproductive health risks of EDCs in France.

New Evidence on BPA's Role in Adipose Tissue Development of Proinflammatory Processes and Its Relationship with Obesity

Bisphenol A (BPA) is a xenobiotic with endocrine disruptor properties which interacts with various receptors, eliciting a cellular response. In the plastic industry, BPA is widely used in the production of polycarbonate and epoxy-phenolic resins to provide elastic properties. It can be found in the lining of canned foods, certain plastic containers, thermal printing papers, composite dental fillings, and medical devices, among other things. Therefore, it is a compound that, directly or indirectly, is in daily contact with the human organism. BPA is postulated to be a factor responsible for the global epidemic of obesity and non-communicable chronic diseases, belonging to the obesogenic and diabetogenic group of compounds. Hence, this endocrine disruptor may be responsible for the development of metabolic disorders, promoting in fat cells an increase in proinflammatory pathways and upregulating the expression and release of certain cytokines, such as IL6, IL1β, and TNFα. These, in turn, at a systemic and local level, are associated with a chronic low-grade inflammatory state, which allows the perpetuation of the typical physiological complications of obesity.

BPA induces placental trophoblast proliferation inhibition and fetal growth restriction by inhibiting the expression of SRB1

Bisphenol-A (BPA) is a common environmental toxicant that is known to be associated with fetal growth restriction (FGR). However, the mechanisms of how BPA induce FGR is poorly characterized. We conducted proteomics to identify the abnormal expression of SRB1 in female placental tissues with high BPA-induced FGR and further verified its decreased expression in human placenta and BeWo cells. Next, the effect of BPA on fetal development was further confirmed in pregnant C57BL/6 mice. The expression of SRB1 was consistently downregulated in human FGR placentas, BPA-exposed trophoblasts and mouse placentas. In addition, we found that SRB1 interacted with PCNA, and BPA exposure indirectly reduced the expression of PCNA and further inhibited placental proliferation. In vitro studies showed that BPA exposure reduced the expression of CDK1, CDK2, cyclin B and phosphorylated Rb in placental trophoblast cells, indicating cell cycle arrest after exposure to BPA. In addition, the expression of γ-H2AX and phosphorylated ATM was upregulated in BPA-exposed trophoblasts, indicating increased DNA damage. Our results indicate that BPA-induced FGR is achieved by reducing the expression of SRB1, inhibiting placental proliferation and increasing DNA damage. Our findings not only explain the mechanism of BPA-associated developmental toxicity but also shed light upon developing novel therapeutic targets.

Bisphenol S Increases Cell Number and Stimulates Migration of Endometrial Epithelial Cells

OBJECTIVE

To determine whether bisphenol S (BPS), a common substitute for bisphenol A (BPA), induces cell proliferation and migration in human endometrial epithelial cells (Ishikawa) and adult mouse uterine tissues.

METHODOLOGY

Human endometrial Ishikawa cells were exposed to low doses of BPS (1 nM and 100 nM) for 72 hours. Cell proliferation was assessed through the viability assays MTT and CellTiter-Glo®. Wound healing assays were also used to evaluate the migration potential of the cell line. The expression of genes related to proliferation and migration was also determined. Similarly, adult mice were exposed to BPS at a dose of 30 mg/kg body weight/day for 21 days, after which, the uterus was sent for histopathologic assessment.

RESULTS

BPS increased cell number and stimulated migration in Ishikawa cells, in association with the upregulation of estrogen receptor beta (ESR2) and vimentin (VIM). In addition, mice exposed to BPS showed a significantly higher mean number of endometrial glands within the endometrium.

CONCLUSION

Overall, in vitro and in vivo results obtained in this study showed that BPS could significantly promote endometrial epithelial cell proliferation and migration, a phenotype also observed with BPA exposure. Hence, the use of BPS in BPA-free products must be reassessed, as it may pose adverse reproductive health effects to humans.

Unexpected Interacting Effects of Physical (Radiation) and Chemical (Bisphenol A) Treatments on Male Reproductive Functions in Mice

For decades, numerous chemical pollutants have been described to interfere with endogenous hormone metabolism/signaling altering reproductive functions. Among these endocrine disrupting substances, Bisphenol A (BPA), a widely used compound, is known to negatively impact germ and somatic cells in the testis. Physical agents, such as ionizing radiation, were also described to perturb spermatogenesis. Despite the fact that we are constantly exposed to numerous environmental chemical and physical compounds, very few studies explore the impact of combined exposure to chemical and physical pollutants on reproductive health. The aim of this study was to describe the impact of fetal co-exposure to BPA and IR on testicular function in mice. We exposed pregnant mice to 10 µM BPA (corresponding to 0.5 mg/kg/day) in drinking water from 10.5 dpc until birth, and we irradiated mice with 0.2 Gy (γ-ray, RAD) at 12.5 days post-conception. Co-exposure to BPA and γ-ray induces DNA damage in fetal germ cells in an additive manner, leading to a long-lasting decrease in germ cell abundance. We also observed significant alteration of adult steroidogenesis by RAD exposure independently of the BPA exposure. This is illustrated by the downregulation of steroidogenic genes and the decrease of the number of adult Leydig cells. As a consequence, courtship behavior is modified, and male ultrasonic vocalizations associated with courtship decreased. In conclusion, this study provides evidence for the importance of broadening the concept of endocrine disruptors to include physical agents, leading to a reevaluation of risk management and regulatory decisions.