Epigenetic Methylation Changes in Pregnant Women: Bisphenol Exposure and Atopic Dermatitis

Bisphenol is a chemical substance widely used in plastic products and food containers. In this study, we observed a relationship between DNA methylation and atopic dermatitis (AD) in the peripheral blood mononuclear cells (PBMCs) of pregnant women exposed to bisphenol A (BPA) and its alternatives, bisphenol S (BPS) and bisphenol F (BPF). DNA methylation is an epigenetic mechanism that regulates gene expression, which can be altered by environmental factors, and affects the onset and progression of diseases. We found that genes belonging to the JAK-STAT and PI3K-AKT signaling pathways were hypomethylated in the blood of pregnant women exposed to bisphenols. These genes play important roles in skin barrier function and immune responses, and may influence AD. Therefore, we suggest that not only BPA, but also BPS and BPF, which are used as alternatives, can have a negative impact on AD through epigenetic mechanisms.

A novel strategy for the study on molecular mechanism of prostate injury induced by 4,4'-sulfonyldiphenol based on network toxicology analysis

The study aimed to investigate the underlying molecular mechanisms of prostate injury induced by 4,4'-sulfonyldiphenol (BPS) exposure and propose a novel research strategy to systematically explore the molecular mechanisms of toxicant-induced adverse health effects. By utilizing the ChEMBL, STITCH, and GeneCards databases, a total of 208 potential targets associated with BPS exposure and prostate injury were identified. Through screening the potential target network in the STRING database and Cytoscape software, we determined 21 core targets including AKT1, EGFR, and MAPK3. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses conducted through the DAVID database illustrated that the potential targets of BPS in prostatic toxicity were primarily enriched in cancer signaling pathways and calcium signaling pathways. These findings suggest that BPS may actively participate in the occurrence and development of prostate inflammation, prostatic hyperplasia, prostate cancer, and other aspects of prostate injury by regulating prostate cancer cell apoptosis and proliferation, activating inflammatory signaling pathways, and modulating prostate adipocytes and fibroblasts. This research provides a theoretical basis for understanding the molecular mechanism of underlying BPS-induced prostatic toxicity and establishes a foundation for the prevention and treatment of prostatic diseases associated with exposure to plastic products containing BPS and certain BPS-overwhelmed environments.

PPARα Senses Bisphenol S to Trigger EP300-Mediated Autophagy Blockage and Hepatic Steatosis

The internal exposure dose of bisphenol S (BPS) is increasing since its use as a substitute for BPA. The relationship between BPS and nonalcoholic liver disease (NAFLD) and the underlying mechanism remain unclarified. In this study, we evaluated the correlation of BPS with NAFLD in populations from the Jiangsu Survey and the 2013-2016 National Health Nutrition Examination Survey and unraveled the molecular pathway by which BPS blocked hepatic autophagy, contributing to lipid accumulation. The study found that serum and urine BPS were associated with NAFLD risks in both the Chinese and US populations. For each additional unit of the BPS level, the NAFLD risk increased by 3.163-fold (serum) and 3.979-fold (urine) in the Chinese population. In addition, after BPS exposure at a dose equivalent to human exposure for 20 weeks, mice developed liver lipid accumulation. BPS could trigger PPARα-mediated transcriptional activation of EP300 expression. BPS promoted the translocation of EP300 from the nucleus to the cytoplasm to regulate the acetylation of Raptor and the activation of mTORC1, which in turn induced autophagy blockage and interfered with lipid degradation in hepatocytes. Conversely, knockdown of EP300 reduced Raptor acetylation and ameliorated autophagy blockage. This study demonstrated that EP300 was a key enzyme for the development of BPS-related NAFLD and provided novel evidence that BPS causes NAFLD.

Bisphenol S induces brown adipose tissue whitening and aggravates diet-induced obesity in an estrogen-dependent manner

Bisphenol S (BPS) exposure has been implied epidemiologically to increase obesity risk, but the underlying mechanism is unclear. Here, we propose that BPS exposure at an environmentally relevant dose aggravates diet-induced obesity in female mice by inducing brown adipose tissue (BAT) whitening. We explored the underlying mechanism by which KDM5A-associated demethylation of the trimethylation of lysine 4 on histone H3 (H3K4me3) in thermogenic genes is overactivated in BAT upon BPS exposure, leading to the reduced expression of thermogenic genes. Further studies have suggested that BPS activates KDM5A transcription in BAT by binding to glucocorticoid receptor (GR) in an estrogen-dependent manner. Estrogen-estrogen receptors facilitate the accessibility of the KDM5A gene promoter to BPS-activated GR by recruiting the activator protein 1 (AP-1) complex. These results indicate that BAT is another important target of BPS and that targeting KDM5A-related signals may serve as an approach to counteract the BPS-induced susceptivity to obesity.

Association between Environmental Exposure to Multiclass Organic Pollutants and Sex Steroid Hormone Levels in Women of Reproductive Age

Organic pollutant exposure may alter sex steroid hormone levels in both animals and humans, but studies on mixture effects have been lacking and mainly limited to persistent organic pollutants, with few hormones being investigated. Moreover, measurements from a single blood or urine sample may not be able to reflect long-term status. Using hair analysis, here, we evaluated the relationship between multiclass organic pollutants and sex steroid hormones in 196 healthy Chinese women aged 25-45 years. Associations with nine sex steroid hormones, including progesterone, androstenedione (AD), testosterone (T), estrone (E1), and 17β-estradiol (E2), and eight related hormone ratios were explored on 54 pollutants from polychlorinated biphenyl (PCB), pesticide, and bisphenol families using stability-based Lasso regression analysis. Our results showed that each hormone was associated with a mixture of at least 10 examined pollutants. In particular, hair E2 concentration was associated with 19 pollutants, including γ-hexachlorocyclohexane, propoxur, permethrin, fipronil, mecoprop, prochloraz, and carbendazim. There were also associations between pollutants and hormone ratios, with pentachlorophenol, dimethylthiophosphate, 3-phenoxybenzoic acid, and flusilazole being related to both E1/AD and E2/T ratios. Our results suggest that exposure to background levels of pesticides PCB180 and bisphenol S may affect sex steroid hormone homeostasis among women of reproductive age.

Effects of Prenatal Exposure to Bisphenol A Substitutes, Bisphenol S and Bisphenol F, on Offspring's Health: Evidence from Epidemiological and Experimental Studies

Pregnancy and lactation are critical periods for human well-being and are sensitive windows for pollutant exposure. Bisphenol A (BPA) is well demonstrated as a toxicant and has been replaced in the plastic industry with other bisphenol analogs that share similarities in structure and characteristics, most commonly Bisphenol S (BPS) and Bisphenol F (BPF). Maternal exposure to BPS or BPF can result in their accumulation in the fetal compartment, leading to chronic exposure and potentially limiting normal fetal growth and development. This review summarizes considerable findings of epidemiological or experimental studies reporting associations between BPS or BPF and impaired fetal growth and development. Briefly, the available findings indicate that exposure to the two bisphenol analogs during pregnancy and lactation can result in multiple disturbances in the offspring, including fetal growth restrictions, neurological dysfunctions, and metabolic disorders with the potential to persist throughout childhood. The occurrence of premature births may also be attributed to exposure to the two bisphenols. The possible mechanisms of actions by which the two bisphenols can induce such effects can be attributed to a complex of interactions between the physiological mechanisms, including impaired placental functioning and development, dysregulation of gene expression, altered hormonal balance, and disturbances in immune responses as well as induced inflammations and oxidative stress. In conclusion, the available evidence suggests that BPS and BPF have a toxic potential in a compartment level to BPA. Future research is needed to provide more intensive information; long-term studies and epidemiological research, including a wide scale of populations with different settings, are recommended. Public awareness regarding the safety of BPA-free products should also be enhanced, with particular emphasis on educating individuals responsible for the well-being of children.

Bisphenol S stimulates Leydig cell proliferation but inhibits differentiation in pubertal male rats through multiple mechanisms

Bisphenol S (BPS) is a novel bisphenol A (BPA) analogue, a ubiquitous environmental pollutant that disrupts male reproductive system. Whether BPS affects Leydig cell maturation in male puberty remains unclear. Male Sprague-Dawley rats (age of 35 days) were daily gavaged to 0, 1, 10, 100, and 200 mg/kg/day from postnatal days 35-56. BPS at 1-10 mg/kg/day and higher doses markedly reduced serum testosterone and progesterone levels but it at 200 mg/kg/day significantly increased estradiol level. BPS at 100 and 200 mg/kg/day significantly elevated serum luteinizing hormone (LH) levels. BPS at 1-10 mg/kg/day and higher doses significantly reduced inhibin A and inhibin B levels. BPS at 100 and 200 mg/kg/day markedly increased CYP11A1+ Leydig cell number, but did not affect HSD11B1+ (a mature Leydig cell marker) cell number. BPS at 10 mg/kg/day and higher doses significantly downregulated the expression of Cyp11a1 and at 100 and 200 mg/kg/d significantly lowered Cyp17a1, Hsd11b1, and Nr5a1 in the testes. BPS at 100 and/or 200 mg/kg/day significantly elevated Lhb in the pituitary. BPS at 100 and 200 mg/kg/day significantly increased the phosphorylation of AKT1, AKT2, and CREB without affecting total AKT1, AKT2, and CREB levels. BPS at 1-100 μM significantly suppressed testosterone production and induced proliferation of primary immature Leydig cells after 24 h of treatment and these actions were reversed by estrogen receptor α antagonist, ICI 182780, and partially reversed by vitamin E. BPS at 0.1-10 μM significantly increased oxidative stress of Leydig cells in vitro. BPS also directly inhibited 17β-hydroxysteroid dehydrogenase 3 activity at 10-100 μM. In conclusion, BPS causes hypergonadotropic androgen deficiency in male rats during pubertal exposure via activating ESR1 and inducing ROS in immature Leydig cells and directly inhibiting 17β-hydroxysteroid dehydrogenase 3 activity.

Bisphenols-A Threat to the Natural Environment

Negative public sentiment built up around bisphenol A (BPA) follows growing awareness of the frequency of this chemical compound in the environment. The increase in air, water, and soil contamination by BPA has also generated the need to replace it with less toxic analogs, such as Bisphenol F (BPF) and Bisphenol S (BPS). However, due to the structural similarity of BPF and BPS to BPA, questions arise about the safety of their usage. The toxicity of BPA, BPF, and BPS towards humans and animals has been fairly well understood. The biodegradability potential of microorganisms towards each of these bisphenols is also widely recognized. However, the scale of their inhibitory pressure on soil microbiomes and soil enzyme activity has not been estimated. These parameters are extremely important in determining soil health, which in turn also influences plant growth and development. Therefore, in this manuscript, knowledge has been expanded and systematized regarding the differences in toxicity between BPA and its two analogs. In the context of the synthetic characterization of the effects of bisphenol permeation into the environment, the toxic impact of BPA, BPF, and BPS on the microbiological and biochemical parameters of soils was traced. The response of cultivated plants to their influence was also analyzed.

Exposure to Bisphenol A and Its Analogs among Thai School-Age Children

Bisphenol F (BPF) and bisphenol S (BPS) have become popular substitutes for bisphenol A (BPA) in the plastic industry due to concerns over BPA's adverse effects. However, there is limited information on children's exposure to these chemicals. This study aims to assess the extent of BPA, BPF, and BPS exposure and determine factors that influence such exposure. A group of Thai children (age 6-13 years, N = 358) were recruited between October 2019 and 2020. Two first-morning voids were collected one week apart. Demographic and exposure-related information was gathered. Urinary concentrations of bisphenols were analyzed by liquid chromatography and tandem mass spectrometry. Correlation between bisphenol concentrations with age, body weight, and sources of bisphenol exposure, was determined using generalized estimating equations with linear model. BPA, BPF, and BPS were detected at 79.6%, 31.0%, and 16.8%, with geometric mean (GM) concentrations of 1.41, 0.013, and 0.014 ng/mL, respectively. Younger children aged <10 years exhibited 1.3-1.6 times higher GM levels of all bisphenols compared to older children. Exposure to food stored in plastic containers was associated with higher levels of BPF and BPS. In conclusion, BPA was the most frequently detected bisphenol in urine samples from Thai children, followed by BPF and BPS.

Puerarin Prevents Bisphenol S Induced Lipid Accumulation by Reducing Liver Lipid Synthesis and Promoting Lipid Metabolism in C57BL/6J Mice

Bisphenol S (BPS) is an environmental pollutant that can accumulate in the human body and cause harm. Puerarin (PUE) is a flavonoid with anti-inflammatory and antioxidant effects. In this study, we used 50 mg/kg/d BPS as a poison and PUE as an intervention for model mice for 42 d. BPS exposure significantly increased the levels of the impairment of the mice's liver function, T-CHO, TG, LDL-C, ALT, and AST in the BPS group were significantly increased (p < 0.05). Additionally, BPS exposure caused inflammatory cell infiltration in the mice liver tissue and enhanced oxidative stress response, the level of MDA was significantly increased (p < 0.05). The expression of CD36 and pparγ was stimulated after BPS exposure. Moreover, the expression of cpt1a and cpt1b, which promote fatty acid oxidation, was downregulated. After PUE intervention, the levels of genes and proteins involved in lipid synthesis (PPARγ, SREBP1C, and FASN) and metabolism (Cpt1a, Cpt1b, and PPARα) in mice returned to those of the control group, or much higher than those in the BPS group. Therefore, we hypothesized that BPS causes lipid accumulation in the liver by promoting lipid synthesis and reducing lipid metabolism, whereas PUE reduces lipid synthesis and promotes lipid metabolism. Conclusively, our results imply that long-term exposure to BPS in mice affects liver lipid metabolism and that PUE intervention could maintain the liver function of mice at normal metabolic levels.

Influence of bisphenol A and its analog bisphenol S on cocaine- and amphetamine-regulated transcript peptide-positive enteric neurons in the mouse gastrointestinal tract

Introduction

Bisphenol A (BPA) is used in large quantities for the production of plastics and is present in various everyday objects. It penetrates living organisms and shows multidirectional adverse influence on many internal organs. For this reason, BPA is often replaced in plastic production by other substances. One of them is bisphenol S (BPS), whose effects on the enteric nervous system (ENS) have not been explained.

Methods

Therefore, the present study compares the influence of BPA and BPS on the number of enteric neurons immunoreactive to cocaine-and amphetamine-regulated transcript (CART) peptide located in the ENS of the stomach, jejunum and colon with the use of double immunofluorescence method.

Results

The obtained results have shown that both bisphenols studied induced an increase in the number of CART-positive enteric neurons, and the severity of changes depended on the type of enteric ganglion, the dose of bisphenols and the segment of the digestive tract. The most visible changes were noted in the myenteric ganglia in the colon. Moreover, in the colon, the changes submitted by BPS are more noticeable than those observed after BPA administration. In the stomach and jejunum, bisphenol-induced changes were less visible, and changes caused by BPS were similar or less pronounced than those noted under the impact of BPA, depending on the segment of the gastrointestinal tract and ganglion type studied.

Discussion

The results show that BPS affects the enteric neurons containing CART in a similar way to BPA, and the BPS impact is even stronger in the colon. Therefore, BPS is not neutral for the gastrointestinal tract and ENS.

Vitamin E (α-Tocopherol) Does Not Ameliorate the Toxic Effect of Bisphenol S on the Metabolic Analytes and Pancreas Histoarchitecture of Diabetic Rats

This study investigated whether the coadministration of vitamin E (VitE) diminishes the harmful effects provoked by plasticizer bisphenol S (BPS) in the serum metabolites related to hepatic and renal metabolism, as well as the endocrine pancreatic function in diabetic male Wistar rats. Rats were divided into five groups (n = 5-6); the first group was healthy rats (Ctrl group). The other four groups were diabetic rats induced with 45 mg/kg bw of streptozotocin: Ctrl-D (diabetic control); VitE-D (100 mg/kg bw/d of VitE); BPS-D (100 mg/kg bw/d of BPS); The animals from the VitE + BPS-D group were administered 100 mg/kg bw/d of VitE + 100 mg/kg bw/d of BPS. All compounds were administered orally for 30 days. Body weight, biochemical assays, urinalysis, glucose tolerance test, pancreas histopathology, proximate chemical analysis in feces, and the activity of antioxidants in rat serum were assessed. The coadministration of VitE + BPS produced weight losses, increases in 14 serum analytes, and degeneration in the pancreas. Therefore, the VitE + BPS coadministration did not have a protective effect versus the harmful impact of BPS or the diabetic metabolic state; on the contrary, it partially aggravated the damage produced by the BPS. VitE is likely to have an additive effect on the toxicity of BPS.

Associations of bisphenol F and S, as substitutes for bisphenol A, with cardiovascular disease in American adults

Bisphenol A (BPA) exposure may be positively associated with cardiovascular disease (CVD). For more than a past decade, exposure to bisphenol F (BPF) and bisphenol S (BPS), as substitutes for BPA, has gradually increased in the population. Whether BPF and BPS exposure are associated with CVD remains unclear. We used data from the United States National Health and Nutrition Examination Survey (NHANES) from 2013 to 2016. A total of 3,502 participants, including 368 with CVD, were enrolled in the final analysis. Associations of BPA, BPF and BPS with CVD were determined using multivariate logistic regression analysis. The highest level of urinary BPA (≥2.5 ng/ml) was significantly associated with a higher CVD prevalence (odds ratio [OR], 1.58; 95% confidence interval [CI], 1.08-2.3) among all participants in the quartile analysis. In stratified analyses, the highest level of urinary BPA was positively associated with CVD prevalence in males (1.86, 1.1-3.13) and the elderly population (≥60 years old) (1.89, 1.2-2.97). Higher levels of urinary BPF were positively associated with CVD prevalence in females (Q2: 1.81, 1.03-3.18; Q4: 1.73, 1.07-2.79) and in the elderly population (Q3: 1.7, 1.16-2.48). No associations were found between urinary BPS levels and CVD, regardless of whether the participants were stratified by age or sex. In conclusion, exposure to BPA or BPF was positively correlated with CVD prevalence, but an association was not found for exposure to BPS. BPF may not be as safe as assumed for human health.

BPS-induced ovarian dysfunction: Protective actions of melatonin via modulation of SIRT-1/Nrf2/NFĸB and IR/PI3K/pAkt/GLUT-4 expressions in adult golden hamster

Ever-increasing occurrence of plastic-manufacturing industries leads to environmental pollution that has been associated with declined human health and increased incidence of compromised reproductive health. Female subfertility/infertility is a complex phenomenon and environmental toxicants as well as lifestyle factors have a crucial role to play. Bisphenol S (BPS) was believed to be a "safer" replacement of bisphenol A (BPA) but recent data documented its neurotoxic, hepatotoxic, nephrotoxic, and reprotoxic attributes. Hence based on the scarcity of reports, we investigated molecular insights into BPS-induced ovarian dysfunction and protective actions of melatonin against it in adult golden hamsters, Mesocricetus auratus. Hamsters were administered with melatonin (3 mg/kg BW i.p. alternate days) and BPS (150 mg/kg BW orally every day) for 28 days. BPS treatment disrupted hypothalamo-pituitary-ovarian (HPO) axis as evident by reduced gonadotropins such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH), ovarian steroids such as estradiol (E2) and progesterone (P4), thyroid hormones namely triiodothyronine (T3) and thyroxine (T4) and melatonin levels along with their respective receptors (ERα, TRα, and MT-1) thereby reducing ovarian folliculogenesis. BPS exposure also led to ovarian oxidative stress/inflammation by increasing reactive oxygen species and metabolic disturbances. However, melatonin supplementation to BPS restored ovarian folliculogenesis/steroidogenesis as indicated by increased number of growing follicles/corpora lutea and E2/P4 levels. Further, melatonin also stimulated key redox/survival markers such as silent information regulator of transcript-1 (SIRT-1), forkhead box O-1 (FOXO-1), nuclear factor E2-related factor-2 (Nrf2), and phosphoinositide 3-kinase/protein kinase B (PI3K/pAkt) expressions along with enhanced ovarian antioxidant capacity. Moreover, melatonin treatment reduced inflammatory load including ovarian nuclear factor kappa-B (NFĸB), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) expressions, serum tumor necrosis factor α (TNFα), C-reactive protein (CRP) and nitrite-nitrate levels as well as upregulated ovarian insulin receptor (IR), glucose uptake transporter-4 (GLUT-4), connexin-43, and proliferating cell nuclear antigen (PCNA) expressions in ovary thereby ameliorating inflammatory and metabolic alterations due to BPS. In conclusion, we found severe deleterious impact of BPS on ovary while melatonin treatment protected ovarian physiology from these detrimental changes suggesting it to be a potential preemptive candidate against environmental toxicant-compromised female reproductive health.

Changes Caused by Bisphenols in the Chemical Coding of Neurons of the Enteric Nervous System of Mouse Stomach

Bisphenol A (BPA), an organic chemical compound which is widely used in the production of plastics, can severely damage live organisms. Due to these findings, the plastic industry has started to replace it with other substances, most often with bisphenol S (BPS). Therefore, during the present investigation, with the use of double immunofluorescence labeling, we compared the effect of BPA and BPS on the enteric nervous system (ENS) in the mouse corpus of the stomach. The obtained results show that both studied toxins impact the amount of nerve cells immunoreactive to substance P (SP), galanin (GAL), vesicular acetylcholine transporter (VAChT is used here as a marker of cholinergic neurons) and vasoactive intestinal polypeptide (VIP). Changes observed under the impact of both bisphenols depended on the neuronal factor, the type of the enteric ganglion and the doses of bisphenols studied. Generally, the increase in the percentage of neurons immunoreactive to SP, GAL and/or VIP, and the decrease in the percentage of VAChT-positive neurons, was noted. Severity of changes was more visible after BPA administration. However, the study has shown that long time exposure to BPS also significantly affects the ENS.

Comparative evaluation of the effects of bisphenol derivatives on oxidative stress parameters in HepG2 cells

Bisphenol A (BPA) BPA is an endocrine-disrupting chemical that has a wide range of uses. Exposure to BPA can be by oral, inhalation, and parenteral routes. Although its use in several products is limited, there is still concern on its adverse health effects, particularly for susceptible populations like children. Alternative bisphenols, such as bisphenol S (BPS) and bisphenol F (BPF), are now being used instead of BPA, although there is little information on the toxicity of these bisphenols. BPF is used as a plasticizer in the production of several industrial materials as well as in the coating of drinks and food cans. BPS is used in curing fast-drying epoxy glues, as a corrosion inhibitor and as a reactant in polymer reactions. In this study, the possible toxic effects of BPA, BPS, and BPF in HepG2 cells were evaluated comparatively. For this purpose, their effects on cytotoxicity, production of intracellular reactive oxygen species (ROS), oxidant/antioxidant parameters, and DNA damage have been examined. The cytotoxicity potentials of different bisphenols were found to be as BPS > BPF > BPA. All bisphenol derivatives caused increases in intracellular ROS production. We observed that all bisphenol derivatives cause an imbalance in some oxidant/antioxidant parameters. Bisphenols also caused significant DNA damage in order of BPF > BPA > BPS. We can suggest that both of the bisphenol derivatives used as alternatives to BPA also showed similar toxicities and may not be considered as safe alternatives. Mechanistic studies are needed to elucidate this issue.

Bisphenol S induces oxidative stress-mediated impairment of testosterone synthesis by inhibiting the Nrf2/HO-1 signaling pathway

Bisphenol S (BPS) is an environmental endocrine disruptor widely used in industrial production. BPS induces oxidative stress and exhibits male reproductive toxicity in mice, but the mechanisms by which BPS impairs steroid hormone synthesis are not fully understood. Nuclear factor erythroid 2-related factor 2(Nrf2)/HO-1 signaling is a key pathway in improving cellular antioxidant defense capacities. Therefore, this study explored the effects of exposure to BPS on testosterone synthesis in adult male mice and its mechanisms with regard to the Nrf2/HO-1 signaling pathway. Adult male C57BL/6 mice were orally exposed to BPS (2, 20, and 200 mg/kg BW) with sesame oil as a vehicle (0.1 ml/10 g BW) per day for 28 consecutive days. The results showed that compared with the control group, serum testosterone levels were substantially reduced in the 20 and 200 mg/kg BPS treatment groups, and testicular testosterone levels were reduced in all BPS treatment groups. These changes were accompanied by a prominent decrease in the expression levels of testosterone synthesis-related enzymes (STAR, CYP11A1, CYP17A1, HSD3B1, and HSD17B3) in the mouse testis. In addition, BPS induced oxidative stress in the testis by upregulating the messenger RNA and protein levels of Keap1 and downregulating the levels of Nrf2, HO-1, and downstream antioxidant enzymes (CAT, SOD1, and Gpx4). In summary, our results indicate that exposure of adult male mice to BPS can inhibit Nrf2/HO-1 signaling and antioxidant enzyme activity, which induces oxidative stress and thereby may impair testosterone synthesis in testicular tissues, leading to reproductive damage.

Modulation of Osteogenic Gene Expression by Human Osteoblasts Cultured in the Presence of Bisphenols BPF, BPS, or BPAF

Bone effects attributed to bisphenols (BPs) include the inhibition of growth and differentiation. This study analyzes the effect of BPA analogs (BPS, BPF, and BPAF) on the gene expression of the osteogenic markers RUNX2, osterix (OSX), bone morphogenetic protein-2 (BMP-2), BMP-7, alkaline phosphatase (ALP), collagen-1 (COL-1), and osteocalcin (OSC). Human osteoblasts were obtained by primary culture from bone chips harvested during routine dental work in healthy volunteers and were treated with BPF, BPS, or BPAF for 24 h at doses of 10^-5, 10^-6, and 10^-7 M. Untreated cells were used as controls. Real-time PCR was used to determine the expression of the osteogenic marker genes RUNX2, OSX, BMP-2, BMP-7, ALP, COL-1, and OSC. The expression of all studied markers was inhibited in the presence of each analog; some markers (COL-1; OSC, BMP2) were inhibited at all three doses and others only at the highest doses (10^-5 and 10^-6 M). Results obtained for the gene expression of osteogenic markers reveal an adverse effect of BPA analogs (BPF, BPS, and BPAF) on the physiology of human osteoblasts. The impact on ALP, COL-1, and OSC synthesis and therefore on bone matrix formation and mineralization is similar to that observed after exposure to BPA. Further research is warranted to determine the possible contribution of BP exposure to the development of bone diseases such as osteoporosis.

Bisphenol S Impairs Behaviors through Disturbing Endoplasmic Reticulum Function and Reducing Lipid Levels in the Brain of Zebrafish

The number of neurotoxic pollutants is increasing, but their mechanism of action is unclear. Here, zebrafish were exposed to 0, 1, 10, and 100 μg/L bisphenol S (BPS) for different durations beginning at 2 h postfertilization (hpf) to explore the neurotoxic mechanisms of BPS. Zebrafish larvae exposed to BPS displayed abnormal neurobehaviors. At 48 and 120 hpf, BPS inhibited yolk lipid consumption and reduced the lipid distribution in the zebrafish brain. Moreover, BPS downregulated the mRNA levels of genes involved in fatty acid elongation in the endoplasmic reticulum (ER) and activated ER stress pathways at 48 and 120 hpf, and KEGG analysis after RNA-seq showed that the protein processing pathway in the ER was significantly enriched after BPS exposure. Exposure to ER toxicants (thapsigargin and tunicamycin), two positive controls, induced neurotoxic effects on zebrafish embryos and larvae similar to those of BPS exposure. These data suggested that BPS and ER toxicants disturbed ER function and reduced brain lipid levels. Continued exposure to BPS into adulthood not only inhibited brain fatty acid elongation and ER function but also caused abnormal swelling of the ER in zebrafish. Our data provide new insights into the neurotoxic mechanism of BPS.

Exposure to Bisphenol A Substitutes, Bisphenol S and Bisphenol F, and Its Association with Developing Obesity and Diabetes Mellitus: A Narrative Review

Bisphenol A, a well-known endocrine-disrupting chemical, has been replaced with its analogs bisphenol S (BPS) and bisphenol F (BPF) over the last decade due to health concerns. BPS and BPF are present in relatively high concentrations in different products, such as food products, personal care products, and sales receipts. Both BPS and BPF have similar structural and chemical properties to BPA; therefore, considerable scientific efforts have investigated the safety of their exposure. In this review, we summarize the findings of relevant epidemiological studies investigating the association between urinary concentrations of BPS and/or BPF with the incidence of obesity or diabetes. The results showed that BPS and BPF were detected in many urinary samples at median concentrations ranging from 0.03 to 0.4 µg·L^-1. At this exposure level, BPS median urinary concentrations (0.4 µg·L^-1) were associated with the development of obesity. At a lower exposure level (0.1-0.03 µg·L^-1), two studies showed an association with developing diabetes. For BPF exposure, only one study showed an association with obesity. However, most of the reported studies only assessed BPS exposure levels. Furthermore, we also summarize the findings of experimental studies in vivo and in vitro regarding our aim; results support the possible obesogenic effects/metabolic disorders mediated by BPS and/or BPF exposure. Unexpectedly, BPS may promote worse obesogenic effects than BPA. In addition, the possible mode of action underlying the obesogenic effects of BPS might be attributed to various pathophysiological mechanisms, including estrogenic or androgenic activities, alterations in the gene expression of critical adipogenesis-related markers, and induction of oxidative stress and an inflammatory state. Furthermore, susceptibility to the adverse effects of BPS may be altered by sex differences according to the results of both epidemiological and experimental studies. However, the possible mode of action underlying these sex differences is still unclear. In conclusion, exposure to BPS or BPF may promote the development of obesity and diabetes. Future approaches are highly needed to assess the safety of BPS and BPF regarding their potential effects in promoting metabolic disturbances. Other studies in different populations and settings are highly suggested.

Evaluation of the therapeutic role of allopurinol on Bisphenol S gastric and renal toxicity in adult male albino rats: An in vivo study

Bisphenol S (BPS) is used as an alternative to bisphenol A (BPA) in polycarbonate plastics, epoxy resins and thermal receipt sheet manufacturing. We examined the toxic effects of BPS on gastric and renal functions, as well as the efficacy of allopurinol as a treatment. Albino rats were given only BPS (30 and 120 mg/kg BW/day) and some were treated with allopurinol prior to sacrifice. Gastric and renal specimens were evaluated histologically and immunohistochemically and blood from the tail vein was analysed for levels of gastrin, uric acid (UA), erythropoietin and 8-deoxyguanosine (8-OHdG) levels. Gastrin levels decreased while erythropoietin, UA and 8-OHdG levels increased significantly. The severity of gastric and renal damage observed in BPS-treated animals increased with increasing doses. The mean percentage of COX-2 immunoreactivity and the mean number of CD45 immunoreactive cells was significantly increased in the stomach and kidney of BPS rats. Allopurinol ameliorated the biochemical, histological and immunohistochemical alterations induced by BPS, with superior protection at lower doses. Allopurinol can reverse the effects of BPS on the stomach and kidneys.

Bisphenols A and S Alter the Bioenergetics and Behaviours of Normal Urothelial and Bladder Cancer Cells

Bisphenol A (BPA) and bisphenol S (BPS) are used in the production of plastics. These endocrine disruptors can be released into the environment and food, resulting in the continuous exposure of humans to bisphenols (BPs). The bladder urothelium is chronically exposed to BPA and BPS due to their presence in human urine samples. BPA and BPS exposure has been linked to cancer progression, especially for hormone-dependent cancers. However, the bladder is not recognized as a hormone-dependent tissue. Still, the presence of hormone receptors on the urothelium and their role in bladder cancer initiation and progression suggest that BPs could impact bladder cancer development. The effects of chronic exposure to BPA and BPS for 72 h on the bioenergetics (glycolysis and mitochondrial respiration), proliferation and migration of normal urothelial cells and non-invasive and invasive bladder cancer cells were evaluated. The results demonstrate that chronic exposure to BPs decreased urothelial cells' energy metabolism and properties while increasing them for bladder cancer cells. These findings suggest that exposure to BPA and BPS could promote bladder cancer development with a potential clinical impact on bladder cancer progression. Further studies using 3D models would help to understand the clinical consequences of this exposure.

The BDNF-TrkB-CREB Signalling Pathway Is Involved in Bisphenol S-Induced Neurotoxicity in Male Mice by Regulating Methylation

Bisphenol S (BPS), the most common substitute for bisphenol A in manufacturing, is associated with neurotoxicity, but its molecular mechanisms are unclear. Here, we studied the role of the BDNF-TrkB-CREB (brain-derived neurotrophic factor-tropomyosin-related kinase B-CAMP response element-binding protein) signalling pathway in bisphenol S-induced neurotoxicity via methylation regulation in male C57BL/6 mice. The mice were treated with sesame oil or 2, 20 and 200 mg/kg body weight BPS for 28 consecutive days, and the hippocampus was extracted. We recorded the body weight, organ index, and hippocampal pathology and ultrastructure of the mice. The BDNF, TrkB, CREB, phosphorylated (p)-CREB, DNMTs (DNA methyltransferases) levels were determined by qRT-PCR and/or Western blotting. BDNF promoter IV methylation level was detected by bisulfite sequencing PCR. BPS damaged the mouse hippocampus ultrastructure and reduced the number of synapses. Further, it increased the methylation rate of BDNF promoter IV; downregulated BDNF, CREB, p-CREB/CREB and DNMT1 expression; and upregulated DNMT3a and DNMT3b expression. Therefore, we speculate that the BDNF-TrkB-CREB pathway may be involved in BPS-induced neurotoxicity in male mice by regulating methylation.

Temporal trend of bisphenol S occurrence in meat samples from 2008-2020 Canadian total diet study

In our previous study, bisphenol S (BPS) was detected unexpectedly and at high levels in meat samples from 2016 and 2020 Canadian total diet study (TDS). In this study, samples of meat and meat products from 2008-2015 and 2017-2019 TDS were also analysed to investigate the consistency of BPS occurrence in meat and identify possible trends and provide some information on the potential sources for BPS in meat. BPS was detected again with the highest levels observed in samples of fresh pork (105 ng/g) and veal cutlets (140 ng/g) from the 2008 TDS. This indicates that the occurrence of BPS in meat is not a recent phenomenon but rather an existing one since 2008 or even earlier. BPS concentrations in meat samples from the 2008 to 2020 TDS varied significantly, e.g. 1.2-118 ng/g in roast beef, 1.8-140 ng/g in veal cutlets, but no trend was observed. The lack of trend for BPS over the period of 13 years (2008-2020) does not support the speculation that BPS is being used to replace BPA in food packaging, and sources other than food packaging may be possible and should be investigated for BPS.

The Bisphenols Found in the Ejaculate of Men Does Not Pass through the Testes

Exposure to bisphenols is related to negative effects on male reproduction. The bisphenols exposure is associated with several modes of action including negative impact on the blood–testis barrier (BTB) in testes or direct effect on spermatozoa. Bisphenols have been detected in human seminal plasma, but the possible mechanism of seminal transfer of bisphenols is not clear. Some authors consider the transfer through the blood–testis barrier to be crucial. Therefore, in this work, we compared normozoospermic men and men after vasectomy who have interrupted vas deferens and their ejaculate does not contain testicular products. We measured the concentration of bisphenol A (BPA), bisphenol S (BPS) and bisphenol F (BPF) in the urine and seminal plasma of these men using liquid chromatography tandem mass spectrometry (LC/MSMS). We found that the ratio of urinary and seminal plasma content of bisphenols did not differ in normozoospermic men or men after vasectomy. From the obtained data, it can be concluded that the pathways of transport of bisphenols into seminal plasma are not primarily through the testicular tissue, but this pathway is applied similarly to other routes of transmission by a corresponding ejaculate volume ratio. To a much greater extent than through testicular tissue, bisphenols enter the seminal plasma mainly as part of the secretions of the accessory glands.

Bisphenol S favors hepatic steatosis development via an upregulation of liver MCT1 expression and an impairment of the mitochondrial respiratory system

Bisphenol S (BPS) is a common substitute of bisphenol A (BPA). Recent data suggest that BPS acts as an obesogenic endocrine disruptor with emerging implications in the physiopathology of metabolic syndrome. However, the effects of BPS on monocarboxylate transporters (acting as carriers for lactate, pyruvate, and ketone bodies) and the mitochondrial respiratory system in the liver remain limited. For this purpose, male Swiss mice were treated with BPS at 100 µg/kg/day for 10 weeks, in drinking water. An increase in body weight and food intake was observed with no increase in locomotor activity. Moreover, data show that BPS increases hepatic MCT1 (a key energetic fuel transporter) mRNA expression accompanied by hepatic steatosis initiation and lipid accumulation, while disrupting mitochondrial function and oxidative stress parameters. Furthermore, BPS produced a significant increase in lactate dehydrogenase and creatine kinase activities. We can suggest that BPS contributes to hepatic steatosis in mice by upregulating monocarboxylate transporters and affecting the bioenergetic status characterized by an impaired mitochondrial respiratory system. Thus, our data highlight a new mechanism putatively implicated in hepatic steatosis development during BPS-induced obesity involving lactate metabolism.

Photoaging of Baby Bottle-Derived Polyethersulfone and Polyphenylsulfone Microplastics and the Resulting Bisphenol S Release

This study evaluated the release of bisphenol S (BPS) from polyethersulfone (PES) and polyphenylsulfone microplastics (MPs) derived from baby bottles under UV irradiation. Released BPS fluctuates over time because it undergoes photolysis under UV₂₅₄ irradiation. Under UV₃₆₅ irradiation, the highest released concentration at 50 °C was 1.7 and 3.2 times that at 35 and 25 °C, respectively, as the activation energy of the photochemical reactions responsible for MP decay was reduced at high temperatures. Low concentrations of humic acid (HA, ≤10 mg·L^-1) promote BPS release because HA acts as a photosensitizer. A high concentration of HA (10∼50 mg·L^-1) decreases the BPS release because HA shields MPs from light and scavenges reactive radicals that are produced via photochemical reactions. For example, under UV irradiation, hydroxyl radicals (•OH) attack results in the breakage of ether bonds and the formation of phenyl radicals (Ph•) and phenoxy radicals (Ph-O•).The•OH addition and hydrogen extractions further produce BPS from the decayed MPs. A leaching kinetics model was developed and calibrated by the experimental data. The calibrated model predicts the equilibrium level of BPS release from MPs that varies with the surface coverage density of BPS and leaching rate constants. This study provides groundwork that deepens our understanding of environmental aging and the chemical release of MPs.

Effects of BPA, BPS, and BPF on Oxidative Stress and Antioxidant Enzyme Expression in Bovine Oocytes and Spermatozoa

Bisphenol A (BPA) and its analogs, bisphenol S (BPS) and bisphenol F (BPF), might impact fertility by altering oxidative stress pathways. Here, we hypothesize that bisphenols-induced oxidative stress is responsible for decreased gamete quality. In both female (cumulus-oocyte-complexes-COCs) and male (spermatozoa), oxidative stress was measured by CM-H2DCFDA assay and key ROS scavengers (SOD1, SOD2, GPX1, GPX4, CAT) were quantified at the mRNA and protein levels using qPCR and Western blot (COCs)/immunofluorescence (sperm). Either gamete was treated in five groups: control, vehicle, and 0.05 mg/mL of BPA, BPS, or BPF. Our results show elevated ROS in BPA-treated COCs but decreased production in BPS- and BPF-treated spermatozoa. Additionally, both mRNA and protein expression of SOD2, GPX1, and GPX4 were decreased in BPA-treated COCs (p < 0.05). In sperm, motility (p < 0.03), but not morphology, was significantly altered by bisphenols. SOD1 mRNA expression was significantly increased, while GPX4 was significantly reduced. These results support BPA's ability to alter oxidative stress in oocytes and, to a lesser extent, in sperm. However, BPS and BPF likely act through different mechanisms.

Bisphenol S Impairs Invasion and Proliferation of Extravillous Trophoblasts Cells by Interfering with Epidermal Growth Factor Receptor Signaling

The placenta supports fetal growth and is vulnerable to exogenous chemical exposures. We have previously demonstrated that exposure to the emerging chemical bisphenol S (BPS) can alter placental endocrine function. Mechanistically, we have demonstrated that BPS interferes with epidermal growth factor receptor (EGFR) signaling, reducing placenta cell fusion. Extravillous trophoblasts (EVTs), a placenta cell type that aids with vascular remodeling, require EGF to invade into the maternal endometrium. We hypothesized that BPS would impair EGF-mediated invasion and proliferation in EVTs. Using human EVTs (HTR-8/SVneo cells), we tested whether BPS could inhibit the EGF response by blocking EGFR activation. We also evaluated functional endpoints of EGFR signaling, including EGF endocytosis, cell invasion and proliferation, and endovascular differentiation. We demonstrated that BPS blocked EGF-induced phosphorylation of EGFR by acting as a competitive antagonist to EGFR. Transwell assay and a three-dimensional microfluidic chip invasion assay revealed that BPS exposure can block EGF-mediated cell invasion. BPS also blocked EGF-mediated proliferation and endovascular differentiation. In conclusion, BPS can prevent EGF-mediated EVT proliferation and invasion through EGFR antagonism. Given the role of EGFR in trophoblast proliferation and differentiation during placental development, our findings suggest that maternal exposure to BPS may contribute to placental dysfunction via EGFR-mediated mechanisms.

Bisphenol S Alters the Steroidome in the Preovulatory Follicle, Oviduct Fluid and Plasma in Ewes With Contrasted Metabolic Status

Bisphenol A (BPA), a plasticizer and endocrine disruptor, has been substituted by bisphenol S (BPS), a structural analogue that had already shown adverse effects on granulosa cell steroidogenesis. The objective of this study was to assess the effect of chronic exposure to BPS, a possible endocrine disruptor, on steroid hormones in the ovary, oviduct and plasma using the ewe as a model. Given the interaction between steroidogenesis and the metabolic status, the BPS effect was tested according to two diet groups. Eighty adult ewes were allotted to restricted (R) and well-fed (WF) groups, that were further subdivided into two subgroups. Ewes were exposed to 50 µg BPS/kg/day in their diet (R50 and WF50 groups) or were unexposed controls (R0 and WF0 groups). After at least 3 months of BPS exposure, preovulatory follicular fluid, oviduct fluid and plasma were collected and steroid hormones were analyzed by gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). A deleterious effect of restricted diet on the volume of oviduct fluid and numbers of pre-ovulatory follicles was observed. Exposure to BPS impaired estradiol concentrations in both follicular and oviduct fluids of well-fed ewes and progesterone, estradiol and estrone concentrations in plasma of restricted ewes. In addition, a significant interaction between metabolic status and BPS exposure was observed for seven steroids, including estradiol. In conclusion, BPS acts in ewes as an endocrine disruptor with differential actions according to metabolic status.

A Comparative Study of Effects of 28-Day Exposure of Bisphenol A and Bisphenol S on Body Weight Changes, Organ Histology, and Relative Organ Weight

Context

Bisphenol A (BPA), a known endocrine disrupting chemical, is of widespread use in manufacturing of plastic products. Documenting ill health effects of BPA has led the plastic industrialists to replace BPA by its alleged safer alternative, bisphenol S (BPS). BPS belongs to the same chemical family and shares endocrine disrupting properties with BPA.

Aims

We compared the effects of 28-day exposure of BPA and BPS on body weight changes, organ histology, and relative organ weight in rats. In addition, we detected BPA and BPS in the rat's blood serum.

Settings and Design

Adult male albino rats were administered BPA (50 mg/kg/day) or BPS (50 mg/kg/day) or equivolume vehicle in different groups by oral gavage for 28 days.

Subjects and Methods

The weight of each rat was noted at the commencement of the study and weekly afterward. On 29^th day, the animals were sampled for whole blood and then sacrificed. The dissected out wet viscera were weighed and subjected to the standard protocol for histological examination. Serum samples were prepared and analyzed for the detection of BPA and BPS by high-pressure liquid chromatography.

Statistical Analysis Used

Paired and unpaired Student's t-test, one-way ANOVA test, and Bonferroni test for multiple comparisons were used, as required for statistical analysis, and P < 0.05 was considered statistically significant.

Results

Both BPA and BPS produced similar detrimental changes in body weight, histology of stomach, small intestine, lung, and kidney, and relative organ weight of lung and kidney. BPA and BPS detected in the serum of rats were nearly 45 times of the control.

Conclusions

Present data suggest caution about the application of BPS as a substitute of BPA.

Bisphenol A and Its Analogues Deteriorate the Hormones Physiological Function of the Male Reproductive System: A Mini-Review

BPA is identified as an endocrine-disrupting chemical that deteriorates the physiological function of the hormones of the male reproductive system. Bisphenol F (BPF), bisphenol S (BPS), and bisphenol AF (BPAF) are actively explored as substitutes for BPA and are known as BPA analogues in most manufacturing industries. These analogues may demonstrate the same adverse effects as BPA on the male reproductive system; however, toxicological data explaining the male reproductive hormones' physiological functions are still limited. Hence, this mini-review discusses the effects of BPA and its analogues on the physiological functions of hormones in the male reproductive system, focusing on the hypothalamus-pituitary-gonad (HPG) axis, steroidogenesis, and spermatogenesis outcomes. The BPA analogues mainly show a similar negative effect on the hormones' physiological functions, proven by alterations in the HPG axis and steroidogenesis via activation of the aromatase activity and reduction of spermatogenesis outcomes when compared to BPA in in vitro and in vivo studies. Human biomonitoring studies also provide significant adverse effects on the physiological functions of hormones in the male reproductive system. In conclusion, BPA and its analogues deteriorate the physiological functions of hormones in the male reproductive system as per in vitro, in vivo, and human biomonitoring studies.

Oxidative stress responses of a freshwater fish, Labeo rohita, to a xenobiotic, bisphenol S

Bisphenol S (BPS) is an organic chemical that has been used as a substitute for bisphenol A (BPA) in making polycarbonate plastics, epoxy resins, thermal receipt papers, and currency bills, as BPA has been reported to have dreadful effects on the living system. From this view point, the present study investigates whether BPS has the same or rather more toxic effects like BPA or not. Limited studies were carried out on the effect of BPS on fish. The hepatic antioxidant enzymes such as superoxide dismutase, catalase, glutathione S-transferase, glutathione reductase, and glutathione peroxidase (GPx), along with the nonenzymatic antioxidant, glutathione, in a freshwater fish, Labeo rohita, were selected as biomarkers. The results revealed that the sublethal exposure of BPS significantly influenced the activities of these biomarkers. Lipid peroxidation (LPO) products such as malondialdehyde and conjugate diene levels were also altered by the exposure. The alteration in the levels of antioxidants and LPO products after BPS exposure clearly showed that the fish experienced oxidative stress. Furthermore, the current study showed that BPS is a pollutant with oxidative potential by disrupting the antioxidant enzymes.

Oxidative stress-mediated apoptosis is involved in bisphenol S-induced reproductive toxicity in male C57BL/6 mice

The reproductive toxicity of bisphenol S (BPS) in male mammals and its possible mechanism are not clear. We investigated the effects and possible mechanism of action of BPS on adult male C57BL/6 mice. We found that exposure to 200-mg/kg BPS resulted in a significant decrease in the sperm count in the caput/corpus and cauda epididymis, significantly decreased sperm motility, and significantly increased the sperm deformity. Histological evaluation revealed that BPS exposure caused a decrease of spermatozoa in the lumen of seminiferous tubules and a reduction in the proportion of Stage VII or VIII seminiferous tubules in the BPS-treated groups. Furthermore, ultrastructure analysis revealed BPS-induced mitochondrial damage and apoptosis in spermatogenic cells. Moreover, BPS exposure-induced oxidative stress in testicular tissues. Further, dUTP-biotin nick end labeling (TUNEL) assay showed that BPS induced the apoptosis of spermatogenic cells in a dose-dependent manner. BPS also significantly upregulated cleaved caspase-8, cleaved caspase-9, cleaved caspase-3, Fas, and FasL and significantly downregulated the Bcl-2/Bax ratio. These results suggest that BPS-induced oxidative stress in the testis and spermatogenic cell apoptosis potentially impairs spermatogenesis and sperm function, which may be the mechanism of the reproductive toxicity of BPS. The Fas/FasL and mitochondrial signal pathways may be involved in BPS-induced oxidative stress-related apoptosis. These results suggest that BPS-induced oxidative stress in the testis and spermatogenic cell apoptosis potentially impairs spermatogenesis and sperm function, which may be the mechanism of the reproductive toxicity of BPS. The Fas/FasL and mitochondrial signal pathways may be involved in BPS-induced oxidative stress-related apoptosis.

Factors Associated with Exposure to Dietary Bisphenols in Adolescents

Obesogenic endocrine-disrupting chemicals, such as bisphenol A (BPA) and its analogue bisphenol S (BPS), seem to play an important role in the development of obesity, although contradictory results have been reported. The aim of the present study was to conduct a gender analysis of the factors associated with exposure to dietary bisphenols in 585 Spanish adolescents. Dietary BPA and BPS exposure was assessed using a food frequency questionnaire. Foods and macronutrients accounting for more than 95% of energy intake were selected for analysis. Stepwise regression was used to estimate the foods that most contributed to dietary bisphenol exposure in the sample. Gender-related factors associated with greater dietary bisphenol exposure were evaluated using multivariate logistic regression models. Canned tuna was the main dietary source of BPA and BPS in both adolescent boys and girls. Overweight/obese girls showed a higher risk of high dietary exposure to BPA (odds ratio (OR): 3.38, 95% confidence interval (CI): 1.25-9.07) and total bisphenols (OR: 2.81, 95% CI: 1.03-7.67) in comparison with girls with a BMI lower than 25 kg/m². Present results indicate a positive association of dietary exposure to both total bisphenols and BPA with being overweight/obese in adolescent girls.

Toxicity of bisphenol analogues on the reproductive, nervous, and immune systems, and their relationships to gut microbiome and metabolism: insights from a multi-species comparison

Bisphenols are common chemicals found in plastics and epoxy resins. Over the past decades, many studies have shown that bisphenol A (BPA) is a potential endocrine-disrupting chemical that may cause multisystem toxicity. However, the relative safety of BPA analogues is a controversial subject. Herein, we conducted a review of the reproductive toxicity, neurotoxicity, immunotoxicity, metabolic toxicity and gut microbiome toxicity of the BPA analogues in various species, including Caenorhabditis elegans, zebrafish, turtles, sheep, rodents, and humans. In addition, the mechanisms of action were discussed with focus on bisphenol S and bisphenol F. It was found that these BPA analogues exert their toxic effects on different organs and systems through various mechanisms including epigenetic modifications and effects on cell signaling pathways, microbiome, and metabolome in different species. More research is needed to study the relative toxicity of the lesser-known BPA analogues compared to BPA, both systemically and organ specifically, and to better define the underlying mechanisms of action, in particular, the potentials of disrupting microbiome and metabolism.

Where Is the Good?

Background: Bisphenol A (BPA), a reprotoxic and endocrine-disrupting chemical, has been substituted by alternative bisphenols such as bisphenol F (BPF) and bisphenol S (BPS) in the plastic industry. Despite their detection in placenta and amniotic fluids, the effects of bisphenols on human placental cells have not been characterized. Our objective was to explore in vitro and to compare the toxicity of BPA to its substitutes BPF and BPS to highlight their potential risks for placenta and then pregnancy. Methods: Human placenta cells (JEG-Tox cells) were incubated with BPA, BPF, and BPS for 72 h. Cell viability, cell death, and degenerative P2X7 receptor and caspases activation, and chromatin condensation were assessed using microplate cytometry and fluorescence microscopy. Results: Incubation with BPA, BPF, or BPS was associated with P2X7 receptor activation and chromatin condensation. BPA and BPF induced more caspase-1, caspase-9, and caspase-3 activation than BPS. Only BPF enhanced caspase-8 activity. Conclusions: BPA, BPF, and BPS are all toxic to human placental cells, with the P2X7 receptor being a common key element. BPA substitution by BPF and BPS does not appear to be a safe alternative for human health, particularly for pregnant women and their fetuses.

Bisphenol S is a haemodialysis-associated xenobiotic that is less toxic than bisphenol A

BACKGROUND

Bisphenol S (BPS) is a structural analogue of bisphenol A (BPA) that is found in the environment. BPS may accumulate in anuric patients due to decreased urinary excretion. The toxicity and health effects of BPS are poorly characterized.

METHODS

A cross-over study was performed using polynephron (PN) or polysulphone (PS) dialysers for a short (1 week each, 14 patients) or long (3 months each, 20 patients) period on each dialyser. Plasma BPA, BPS and hippuric acid were assessed by SRM mass spectrometry (SRM-MS). The biological significance of the BPS concentrations found was explored in cultured kidney tubular cells.

RESULTS

In haemodiafiltration (HDF) patients, plasma BPS was 10-fold higher than in healthy subjects (0.53 ± 0.52 versus 0.05 ± 0.01 ng/mL; P = 0.0015), while BPA levels were 35-fold higher (13.23 ± 14.65 versus 0.37 ± 0.12 ng/mL; P = 0.007). Plasma hippuric acid decreased after an HDF session, while BPS and BPA did not. After 3 months of HDF with the same membranes, the BPS concentration was 1.01 ± 0.87 ng/mL for PN users and 0.62 ± 0.21 ng/mL for PS users (P non-statistically significant). In vitro, BPS and BPA leaked from dialysers containing them. In cultured tubular cells, no biological impact (cytotoxicity, inflammatory and oxidative stress gene expression) was observed for BPS up to 200 µM, while BPA was toxic at concentrations ≥100 µM.

CONCLUSIONS

BPS may be released from dialysis membranes, and dialysis patients display high BPS concentrations. However, BPS concentrations are lower than BPA concentrations and no BPS toxicity was observed at concentrations found in patient plasma.

Surface-Enhanced Raman Spectroscopy for Bisphenols Detection: Toward a Better Understanding of the Analyte-Nanosystem Interactions

Silver nanoparticles functionalized with thiolated β-cyclodextrin (CD-SH) were employed for the detection of bisphenols (BPs) A, B, and S by means of surface-enhanced Raman spectroscopy (SERS). The functionalization of Ag nanoparticles with CD-SH leads to an improvement of the sensitivity of the implemented SERS nanosensor. Using a multivariate analysis of the SERS data, the limit of detection of these compounds was estimated at about 10⁻⁷ M, in the range of the tens of ppb. Structural analysis of the CD-SH/BP complex was performed by density functional theory (DFT) calculations. Theoretical results allowed the assignment of key structural vibrational bands related to ring breathing motions and the inter-ring vibrations and pointed out an external interaction due to four hydrogen bonds between the hydroxyl groups of BP and CD located at the external top of the CD cone. DFT calculations allowed also checking the interaction energies of the different molecular species on the Ag surface and testing the effect of the presence of CD-SH on the BPs’ affinity. These findings were in agreement with the experimental evidences that there is not an actual inclusion of BP inside the CD cavity. The SERS sensor and the analysis procedure of data based on partial least square regression proposed here were tested in a real sample consisting of the detection of BPs in milk extracts to validate the detection performance of the SERS sensor.

Role of the BDNF/TrkB/CREB signaling pathway in the cytotoxicity of bisphenol S in SK-N-SH cells

Bisphenol S (BPS) is associated with neurotoxicity, but its molecular mechanisms are unclear. Our aim was to investigate the role of the brain-derived neurotrophic factor (BDNF)/tyrosine kinase B (TrkB)/cAMP-response element-binding protein (CREB) signaling pathway in BPS-induced cytotoxicity in SK-N-SH cells. The cells were treated with various concentrations of BPS, and cell viability, apoptosis rate, mitochondrial membrane potential (MMP), and the BDNF, cleaved-caspase-3, B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), TrkB, CREB, and phospho-CREB (p-CREB) levels were determined. The effects of pretreatment with the TrkB activator 7,8-dihydroxyflavone (7,8-DHF) were also explored. BPS decreased SK-N-SH cell viability and altered their morphology. Their apoptosis rate was increased, as were the levels of the proapoptotic proteins Bax and cleaved-caspase-3, but MMP was decreased. Thus, BPS may induce mitochondria-dependent apoptosis pathways. BPS also reduced the BDNF, TrkB, and p-CREB levels, and pretreatment with 7,8-DHF alleviated its cytotoxic effects. Thus, BPS-induced cytotoxicity might be mediated by the BDNF/TrkB/CREB signaling pathway.

Effects of bisphenol A and S on blood coagulation: in vivo, in vitro and in silico approaches in toxicodynamic

Bisphenol A (BPA) is a well-known endocrine disruptor with several effects on mammalian systems and has been linked to diseases, such as cancer. Bisphenol S (BPS) emerged as a likely alternative to BPA in industrial production. Despite being well studied and exhibiting BPA-like toxic capacity, many effects are still being elucidated. The blood coagulation system is well controlled in an effort to minimize blood loss. To our knowledge, no study reported actions of bisphenols in this system. The aim of this work was to evaluate the effects of bisphenols on blood coagulation. Zebrafish were used to measure bleeding time. To assess possible mechanisms, platelet-rich plasma was incubated with both bisphenols in the presence of arachidonic acid. Prothrombin time (PT) and activated partial thromboplastin time (APTT) assays were performed in the presence of BPA and BPS. Alignment of human factor VII sequence was compared to zebrafish and docking simulations performed with FVIIa and bisphenols. An extended time was observed in BPA-treated but not BPS-treated animals in bleeding time; in PT, bisphenols showed no effect. APTT was increased in the highest concentration of bisphenols, with no effects in platelet aggregation, indicating interference with factor VII. Protein alignment showed that both proteins have well conserved residues, as those being required for interaction of FVIIa-BPA and FVIIa-BPS complexes, as shown in molecular docking. Taken together, these data show BPA and BPS as capable of interfering with the coagulation process via FVIIa.

Genome-wide expression changes induced by bisphenol A, F and S in human stem cell derived hepatocyte-like cells

The debate about possible adverse effects of bisphenol A (BPA) has been ongoing for decades. Bisphenol F (BPF) and S (BPS) have been suggested as “safer” alternatives. In the present study we used hepatocyte-like cells (HLCs) derived from the human embryonic stem cell lines Man12 and H9 to compare the three bisphenol derivatives. Stem cell-derived progenitors were produced using an established system and were exposed to BPA, BPF and BPS for 8 days during their transition to HLCs. Subsequently, we examined cell viability, inhibition of cytochrome P450 (CYP) activity, and genome-wide RNA profiles. Sub-cytotoxic, inhibitory concentrations (IC₅₀) of CYP3A were 20, 9.5 and 25 µM for BPA, BPF and BPS in Man12 derived HLCs, respectively. The corresponding concentrations for H9-derived HLCs were 19, 29 and 31 µM. These IC₅₀ concentrations were used to study global expression changes in this in vitro study and are higher than unconjugated BPA in serum of the general population. A large overlap of up- as well as downregulated genes induced by the three bisphenol derivatives was seen. This is at least 28-fold higher compared to randomly expected gene expression changes. Moreover, highly significant correlations of expression changes induced by the three bisphenol derivatives were obtained in pairwise comparisons. Dysregulated genes were associated with reduced metabolic function, cellular differentiation, embryonic development, cell survival and apoptosis. In conclusion, no major differences in cytochrome inhibitory activities of BPA, BPF and BPS were observed and gene expression changes showed a high degree of similarity.

Comparative toxicokinetics of bisphenol S and bisphenol AF in male rats and mice following repeated exposure via feed

We investigated the plasma toxicokinetic behavior of free (parent) and total (parent and conjugated forms) of bisphenol S (BPS) and bisphenol AF (BPAF) in plasma of adult male rats and mice following exposure via feed for 7 days to BPS (338, 1125, and 3375 ppm) or BPAF (338, 1125, and 3750 ppm). In rats, the exposure concentration-normalized maximum concentration [C_max/D (ng/mL)/(ppm)] and area under the concentration time curve [AUC/D (h × ng/mL)/(ppm)] for free was higher for BPS (C_max/D: 0.476-1.02; AUC/D: 3.58-8.26) than for BPAF (C_max/D: 0.017-0.037; AUC/D:0.196-0.436). In mice, the difference in systemic exposure parameters between free BPS (C_max/D: 0.376-0.459; AUC/D: 1.52-2.54) and free BPAF (C_max/D: 0.111-0.165; AUC/D:0.846-1.09) was marginal. Elimination half-lives for free analytes (4.41-10.4 h) were comparable between species and analogues. When systemic exposure to free analyte was compared between species, in rats, BPS exposure was slightly higher but BPAF exposure was much lower than in mice. BPS and BPAF were highly conjugated; total BPS AUC values (rats ≥18-fold, mice ≥17-fold) and BPAF (rats ≥127-fold, mice ≥16-fold) were higher than corresponding free values. Data demonstrated that there are analogue and species differences in the kinetics of BPS and BPAF.

Environmentally Relevant Concentration of Bisphenol S Shows Slight Effects on SIHUMIx

Bisphenol S (BPS) is an industrial chemical used in the process of polymerization of polycarbonate plastics and epoxy resins and thus can be found in various plastic products and thermal papers. The microbiota disrupting effect of BPS on the community structure of the microbiome has already been reported, but little is known on how BPS affects bacterial activity and function. To analyze these effects, we cultivated the simplified human intestinal microbiota (SIHUMIx) in bioreactors at a concentration of 45 µM BPS. By determining biomass, growth of SIHUMIx was followed but no differences during BPS exposure were observed. To validate if the membrane composition was affected, fatty acid methyl esters (FAMEs) profiles were compared. Changes in the individual membrane fatty acid composition could not been described; however, the saturation level of the membranes slightly increased during BPS exposure. By applying targeted metabolomics to quantify short-chain fatty acids (SCFA), it was shown that the activity of SIHUMIx was unaffected. Metaproteomics revealed temporal effect on the community structure and function, showing that BPS has minor effects on the structure or functionality of SIHUMIx.

Toxicological Evaluation of Bisphenol A and Its Analogues

Bisphenol A (BPA) is known as one of the oldest synthetic compounds with endocrine disrupting activity. It is commonly used in the production of epoxy resins, polycarbonates, dental fillings, food storage containers, baby bottles, and water containers. BPA is associated with various health problems such as obesity, diabetes, chronic respiratory diseases, cardiovascular diseases, renal diseases, behavior disorders, breast cancer, tooth development disorders, and reproductive disorders. Increasing health concerns have led the industry to seek alternatives to BPA. As BPA is now being excluded from several consumer products, the use of alternative compounds is increasing. However, the chemicals used to replace BPA are also BP analogues and may have similar or higher toxicological effects on organisms. The aim of this review is to focus on the toxicological profiles of different BP analogues (i.e. BPS and BPF) which are increasingly used today as alternative to BPA.

Prenatal Exposure to Bisphenol A, E, and S Induces Transgenerational Effects on Male Reproductive Functions in Mice

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.

Prenatal Exposure to Bisphenol A Analogues on Female Reproductive Functions in Mice

This study was performed to examine whether prenatal exposure to bisphenol (BP) A analogues, BPE and BPS, negatively impacts female reproductive functions and follicular development using mice as a model. CD-1 mice were orally exposed to control treatment (corn oil), BPA, BPE, or BPS (0.5, 20, or 50 µg/kg/day) from gestational day 11 (the presence of vaginal plug = 1) to birth. Exposure to BPA, BPE, and BPS accelerated the onset of puberty and exhibited abnormal estrous cyclicity, especially with lower doses. Females exposed to BPA, BPE, and BPS exhibited mating difficulties starting at 6 months of age. By 9 months, mice exhibited various fertility problems including reduced pregnancy rate, parturition issues, and increased dead pups at birth. Furthermore, the levels of serum testosterone were elevated by BPE or BPS exposure at the age of 9 months, whereas estrogen levels were not affected. On the other hand, the dysregulated expression of steroidogenic enzymes was observed in the ovary at 3, 6, or 9 months of age by BPE or BPS exposure. When we examined neonatal ovary on postnatal day 4, BPA, BPE, and BPS exposure inhibited germ cell nest breakdown and reduced number of primary and secondary follicles. These results suggest that prenatal exposure to BPA analogues, BPE, and BPS, have effects on fertility in later reproductive life probably due to the disruption of early folliculogenesis.

Association of Urinary Levels of Bisphenols A, F, and S with Endometriosis Risk: Preliminary Results of the EndEA Study

Aim: The aim of this study was to explore associations of urinary concentrations of bisphenols A (BPA), S (BPS), and F (BPF) and of thiobarbituric acid reactive substances (TBARS) with the risk of endometriosis in women of childbearing age. Methods: This case-control study enrolled 124 women between January 2018 and July 2019: 35 women with endometriosis (cases) and 89 women without endometriosis undergoing abdominal surgery for other reasons (controls). Endometriosis was diagnosed (cases) or ruled out (controls) by laparoscopic inspection of the pelvis and the biopsy of suspected lesions (histological diagnosis). Fasting urine samples were collected before surgery to determine concentrations of BPA, BPS, BPF, and TBARS. Associations of bisphenol and TBARS concentrations with endometriosis risk were explored with multivariate logistic and linear regression analyses. Results: After adjustment for urinary creatinine, age, BMI, parity, and residence, endometriosis risk was increased with each 1 log unit of BPA [OR 1.5; 95%CI 1.0-2.3] and Σbisphenols [OR 1.5; 95%CI 0.9-2.3] but was not associated with the presence of BPS and BPF. Classification of the women by tertiles of exposure revealed statistically significant associations between endometriosis risk and the second tertile of exposure to BPA [OR 3.7; 95%CI 1.3-10.3] and Σbisphenols [OR 5.4; 95%CI 1.9-15.6]. In addition, TBARS concentrations showed a close-to-significant relationship with increased endometriosis risk [OR 1.6; 95%CI 1.0-2.8], and classification by TBARS concentration tertile revealed that the association between endometriosis risk and concentrations of BPA [OR 2.0; 95%CI 1.0-4.1] and Σbisphenols [OR 2.2; 95%CI 1.0-4.6] was only statistically significant for women in the highest TBARS tertile (>4.23 μM). Conclusion: Exposure to bisphenols may increase the risk of endometriosis, and oxidative stress may play a crucial role in this association. Further studies are warranted to verify these findings.

High-Content Image-Based Single-Cell Phenotypic Analysis for the Testicular Toxicity Prediction Induced by Bisphenol A and Its Analogs Bisphenol S, Bisphenol AF, and Tetrabromobisphenol A in a Three-Dimensional Testicular Cell Co-culture Model

Emerging data indicate that structural analogs of bisphenol A (BPA) such as bisphenol S (BPS), tetrabromobisphenol A (TBBPA), and bisphenol AF (BPAF) have been introduced into the market as substitutes for BPA. Our previous study compared in vitro testicular toxicity using murine C18-4 spermatogonial cells and found that BPAF and TBBPA exhibited higher spermatogonial toxicities as compared with BPA and BPS. Recently, we developed a novel in vitro three-dimensional (3D) testicular cell co-culture model, enabling the classification of reproductive toxic substances. In this study, we applied the testicular cell co-culture model and employed a high-content image (HCA)-based single-cell analysis to further compare the testicular toxicities of BPA and its analogs. We also developed a machine learning (ML)-based HCA pipeline to examine the complex phenotypic changes associated with testicular toxicities. We found dose- and time-dependent changes in a wide spectrum of adverse endpoints, including nuclear morphology, DNA synthesis, DNA damage, and cytoskeletal structure in a single-cell-based analysis. The co-cultured testicular cells were more sensitive than the C18 spermatogonial cells in response to BPA and its analogs. Unlike conventional population-averaged assays, single-cell-based assays not only showed the levels of the averaged population, but also revealed changes in the sub-population. Machine learning-based phenotypic analysis revealed that treatment of BPA and its analogs resulted in the loss of spatial cytoskeletal structure, and an accumulation of M phase cells in a dose- and time-dependent manner. Furthermore, treatment of BPAF-induced multinucleated cells, which were associated with altered DNA damage response and impaired cellular F-actin filaments. Overall, we demonstrated a new and effective means to evaluate multiple toxic endpoints in the testicular co-culture model through the combination of ML and high-content image-based single-cell analysis. This approach provided an in-depth analysis of the multi-dimensional HCA data and provided an unbiased quantitative analysis of the phenotypes of interest.

The effects of different bisphenol derivatives on oxidative stress, DNA damage and DNA repair in RWPE-1 cells: A comparative study

Bisphenol A (BPA) is a well-known endocrine disruptor and it is widely used mainly in the plastics industry. Due to recent reports on its possible impact on health (particularly on the male reproductive system), bisphenol F (BPF) and bisphenol S (BPS) are now being used as alternatives. In this study, RWPE-1 cells were used as a model to compare cytotoxicity, oxidative stress-causing potential and genotoxicity of these chemicals. In addition, the effects of the bisphenol derivatives were assessed on DNA repair proteins. RWPE-1 cells were incubated with BPA, BPF, and BPS at concentrations of 0-600 μM for 24 h. The inhibitory concentration 20 (IC₂₀ , concentration that causes 20% of cell viability loss) values for BPA, BPF, and BPS were 45, 65, and 108 μM, respectively. These results indicated that cytotoxicity potentials were ranked as BPA > BPF > BPS. We also found alterations in superoxide dismutase, glutathione peroxidase and glutathione reductase activities, and glutathione and total antioxidant capacity in all bisphenol-exposed groups. In the standard and modified Comet assay, BPS produced significantly higher levels of DNA damage vs the control. DNA repair proteins (OGG1, Ape-1, and MyH) involved in the base excision repair pathway, as well as p53 protein levels were down-regulated in all of the bisphenol-exposed groups. We found that the BPA alternatives were also cytotoxic and genotoxic, and changed the expressions of DNA repair enzymes. Therefore, further studies are needed to assess whether they can be used safely as alternatives to BPA or not.