Bisphenol A, Bisphenol S, and 4-Hydro​xyphenyl 4-Isopro​oxyphenyl​sulfone (BPSIP) in Urine and Blood of Cashiers

Perinatal bisphenol S exposure exacerbates the oxidative burden and apoptosis in neonatal ovaries by suppressing the mTOR/autophagy axis

Bisphenol S (BPS) is an emerging environmental endocrine disruptor capable of crossing the placental barrier, resulting in widespread exposure to pregnant women due to its extensive usage. However, the impact of perinatal maternal exposure to BPS on reproductive health in offspring and the underlying molecular mechanism remain underexplored. In this study, gestational ICR mice were provided with drinking water containing 3.33 mg/L BPS to mimic possible human exposure in some countries. Results demonstrated that BPS accelerated the breakdown of germ-cell cysts and the assembly of primordial follicles in neonates, leading to oocyte over-loss. Furthermore, the expression levels of folliculogenesis-related genes (Kit, Nobox, Gdf9, Sohlh2, Kitl, Bmp15, Lhx8, Figla, and Tgfb1) decreased, thus compromising oocyte quality and disrupting early folliculogenesis dynamics. BPS also disrupted other aspects of offspring reproduction, including advancing puberty onset, disrupting the estrus cycle, and impairing fertility. Further investigation found that BPS exposure inhibited the activities and expression levels of antioxidant-related enzymes in neonatal ovaries, leading to the substantial accumulation of MDA and ROS. The increased oxidative burden exacerbated the intracellular apoptotic signaling, manifested by increased expression levels of pro-apoptotic markers (Bax, Caspase 3, and Caspase 9) and decreased expression levels of anti-apoptotic marker (Bcl2). Concurrently, BPS inhibited autophagy by increasing p-mTOR/mTOR and decreasing p-ULK1/ULK1, subsequently down-regulating autophagy flux-related biomarkers (LC3b/LC3a and Beclin-1) and impeding the degradation of autophagy substrate p62. However, the imbalanced crosstalk between autophagy, apoptosis and oxidative stress homeostasis was restored after rapamycin treatment. Collectively, the findings demonstrated that BPS exposure induced reproductive disorders in offspring by perturbing the mTOR/autophagy axis, and such autophagic dysfunction exacerbated redox imbalance and promoted excessive apoptosis. These results provide novel mechanistic insights into the role of autophagy in mitigating BPS-induced intergenerational reproductive dysfunction.

Description of Solvent-Extractable Chemicals in Thermal Receipts and Toxicological Assessment of Bisphenol S and Diphenyl Sulfone

Research on thermal receipts has previously focused on the toxic effects of dermal exposure from the most publicized developers (e.g., bisphenol A (BPA) and bisphenol S (BPS)), while no studies have reported on the other solvent-extractable compounds therein. Diphenyl sulfone (DPS) is a sensitizer added to thermal receipts, but little is known about DPS concentrations in receipts or potential toxicity. Here, we quantified BPA, BPS, and DPS concentrations and tentatively identified the solvent-extractable compounds of thermal receipts collected from three South Dakota (USA) cities during 2016-2017. An immortalized chicken hepatic cell line, cultured as 3D spheroids, was used to screen effects of DPS, BPS, and 17ß estradiol (E2; 0.1-1000 µM) on cell viability and gene expression changes. These chemicals elicited limited cytotoxicity with LC50 values ranging from 113 to 143 µM, and induced dysregulation in genes associated with lipid and bile acid homeostasis. Taken together, this study generated novel information on solvent-extractable chemicals from thermal receipts and toxicity data for DPS.

Cross sectional study on exposure to BPA and its analogues and semen parameters in Czech men

Exposure to bisphenols has been found to have adverse effects on male reproductive function in animals. Human exposure to bisphenols is widespread. Bisphenol A (BPA) and its analogues, including bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF) are utilized in various consumer products such as food contact materials and dental resins. The effects of these compounds on male fertility and spermatogenesis are unclear and findings from human studies are inconsistent. In this cross-sectional study, we evaluated the influence of BPA, BPS, BPF, BPAF (BPs) measured in semen on number of spermatozoa, total motility, progressive motility, morphology, and DNA fragmentation. We also examined the association of bisphenols (BPs) exposure with patients' occupation. A total of 358 patients aged 17-62 years with BMI 18-42 were included in the study from 2019 to 2021. BPs were extracted using solvent extraction followed by preconcentration step and determined by high-performance liquid chromatography and tandem mass spectrometry (LC/MSMS). Bisphenols were detected in 343 from 349 analysed samples (98.3% of all the samples). In 6 samples, the concentration of all BPs was under the limit of detection and in 20 samples under the limit of quantification. We did not find a statistically significant relationship between occupation and BPs. However, we observed significant correlations between the concentration of BPA and a lower motility and normal morphology. For BPS, a significant correlation with a lower ejaculate volume and a lower total sperm count was found. BPF and BPAF were detected only in 14.3% and 23.9% of samples, respectively. For BPF and BPAF, no significant correlations with spermiogram parameters were observed. Our results show that BPs are widespread in the male population (more than 90% of analysed samples), independently of an occupation and in case of BPA and BPS having a negative impact on spermiogram parameters.

Screening of the Antagonistic Activity of Potential Bisphenol A Alternatives toward the Androgen Receptor Using Machine Learning and Molecular Dynamics Simulation

Over the past few decades, extensive research has indicated that exposure to bisphenol A (BPA) increases the health risks in humans. Toxicological studies have demonstrated that BPA can bind to the androgen receptor (AR), resulting in endocrine-disrupting effects. In recent investigations, many alternatives to BPA have been detected in various environmental media as major pollutants. However, related experimental evaluations of BPA alternatives have not been systematically implemented for the assessment of chemical safety and the effects of structural characteristics on the antagonistic activity of the AR. To promote the green development of BPA alternatives, high-throughput toxicological screening is fundamental for prioritizing chemical tests. Therefore, we proposed a hybrid deep learning architecture that combines molecular descriptors and molecular graphs to predict AR antagonistic activity. Compared to previous models, this hybrid architecture can extract substantial chemical information from various molecular representations to improve the model's generalization ability for BPA alternatives. Our predictions suggest that lignin-derivable bisguaiacols, as alternatives to BPA, are likely to be nonantagonist for AR compared to bisphenol analogues. Additionally, molecular dynamics (MD) simulations identified the dihydrotestosterone-bound pocket, rather than the surface, as the major binding site of bisphenol analogues. The conformational changes of key helix H12 from an agonistic to an antagonistic conformation can be evaluated qualitatively by accelerated MD simulations to explain the underlying mechanism. Overall, our computational study is helpful for toxicological screening of BPA alternatives and the design of environmentally friendly BPA alternatives.

Evaluating the efficiency of the 2020 ban of BPA and BPS in thermal papers in Switzerland

Thermal printing technology requires a color developer to activate the dye under the action of heat. Bisphenol A (BPA) has traditionally been used for this purpose, although it has increasingly been replaced by bisphenol S (BPS) in recent years. Due to concerns regarding their toxicity, the Swiss authorities have banned both BPA and BPS from thermal papers since 2020. The impact of this regulatory decision was evaluated during 3 monitoring campaigns: in 2013-2014, 2019 and 2021. They were used to describe the starting point, the transition phase, and the status after entry into force of the ban, respectively. Whereas the use of BPA as color developer dropped from 82.2% in 2013/14 to 10.8% in 2021, the fraction of BPS-based thermal paper rose from 3.1% to 19.1% during the same period, despite being banned. However, Pergafast® 201 (PF201) is now the main color developer in thermal paper in Switzerland, with an occurrence of 60.3%. Other alternatives such as D-8, TGSA, PPSMU, NKK-1304, BPS-MAE, D-90 and Blue4est® have only been marginally detected. This study demonstrates the efficiency of the regulatory measure and the feasibility to substitute BPA in thermal papers with less-toxic alternatives.

Developmental Programming: Impact of Prenatal Exposure to Bisphenol A on Senescence and Circadian Mediators in the Liver of Sheep

Prenatal exposure to endocrine disruptors such as bisphenol A (BPA) plays a critical role in the developmental programming of liver dysfunction that is characteristic of nonalcoholic fatty liver disease (NAFLD). Circadian and aging processes have been implicated in the pathogenesis of NAFLD. We hypothesized that the prenatal BPA-induced fatty-liver phenotype of female sheep is associated with premature hepatic senescence and disruption in circadian clock genes. The expression of circadian rhythm and aging-associated genes, along with other markers of senescence such as telomere length, mitochondrial DNA copy number, and lipofuscin accumulation, were evaluated in the liver tissue of control and prenatal BPA groups. Prenatal BPA exposure significantly elevated the expression of aging-associated genes GLB1 and CISD2 and induced large magnitude differences in the expression of other aging genes-APOE, HGF, KLOTHO, and the clock genes PER2 and CLOCK-in the liver; the other senescence markers remained unaffected. Prenatal BPA-programmed aging-related transcriptional changes in the liver may contribute to pathological changes in liver function, elucidating the involvement of aging genes in the pathogenesis of liver steatosis.

Comparison of the Effect of BPA and Related Bisphenols on Membrane Integrity, Mitochondrial Activity, and Steroidogenesis of H295R Cells In Vitro

Bisphenol A (BPA) is an endocrine-disruptive chemical that is widely utilized in the production of polycarbonate plastic and epoxy resin, which are used to make a wide range of consumer products, food and drink containers, and medical equipment. When the potential risk of BPA emerged, it was substituted by allegedly less harmful substitutes such as bisphenols S, F, B, and AF. However, evidence suggests that all bisphenols can have endocrine-disruptive effects, while the extent of these effects is unknown. This study aimed to determine effect of BPA, BPAF, BPB, BPF, and BPS on viability and steroidogenesis in human adrenocortical carcinoma cell line in vitro. The cytotoxicity of bisphenols was shown to be considerable at higher doses. However, at low concentrations, it improved viability as well as steroid hormone secretion, indicating that bisphenols have a biphasic, hormetic effect in biological systems. The results are consistent with the hypothesis that bisphenols selectively inhibit some steroidogenic enzymes. These findings suggest that bisphenols have the potential to disrupt cellular steroidogenesis in humans, but substantially more detailed and systematic research is needed to gain a better understanding of the risks associated with bisphenols and their endocrine-disrupting effect on humans and wildlife.

Synthetic Chemicals: What We Have Learned and Still Need to Learn About Their Associations with Childhood Allergy and Asthma

PURPOSE OF REVIEW

Prenatal and childhood exposure to synthetic chemicals, such as phenols and phthalates, have been linked to asthma and allergy, but the extent of this association and the underlying mechanisms are not fully understood. Here we provide an up-to-date review of the evidence linking phenol and phthalate exposure with childhood asthma and allergy and of proposed mechanistic pathways.

RECENT FINDINGS

Five experimental and 12 epidemiological studies that examined associations between exposures to synthetic chemicals to asthma and allergic diseases were included. An additional 14 studies provided mechanistic support for the importance of immune modification through epigenetic regulation, induction of pro-allergic T2 expression, and endocrine disruption. While recent studies have provided further experimental and epidemiological evidence for how these chemical exposures may induce childhood asthma and allergy, the recent literature remains limited. However, emerging mechanistic studies have identified chemical-induced alterations in DNA methylation of genes implicated in allergic inflammation and endocrine disruption as potential pathways. In addition, barriers to decrease exposure to synthetic chemicals at the individual level (facilitated through education) and areas for further action at the organizational and governmental levels are suggested. The latter includes transferring some of the onus from the individual to organizations and legislation to restrict marketing and access to products containing potentially harmful chemicals and provide alternative products. We also suggest future research that focuses on further elucidating pathways between exposure to disease development and identifying strategies to reduce exposure at the population level.

The intestinal microbiota as mediators between dietary contaminants and host health

The gut microbiota sit at an important interface between the host and the environment, and are exposed to a multitude of nutritive and non-nutritive substances. These microbiota are critical to maintaining host health, but their supportive roles may be compromised in response to endogenous compounds. Numerous non-nutritive substances are introduced through contaminated foods, with three common groups of contaminants being bisphenols, phthalates, and mycotoxins. The former contaminants are commonly introduced through food and/or beverages packaged in plastic, while mycotoxins contaminate various crops used to feed livestock and humans alike. Each group of contaminants have been shown to shift microbial communities following exposure; however, specific patterns in microbial responses have yet to be identified, and little is known about the capacity of the microbiota to metabolize these contaminants. This review characterizes the state of existing research related to gut microbial responses to and biotransformation of bisphenols, phthalates, and mycotoxins. Collectively, we highlight the need to identify consistent, contaminant-specific responses in microbial shifts, whether these community alterations are a result of contaminant effects on the host or microbiota directly, and to identify the extent of contaminant biotransformation by microbiota, including if these transformations occur in physiologically relevant contexts.

Bisphenols and alternative developers in thermal paper receipts from the U.S. market assessed by Fourier transform infrared spectroscopy

Cash register receipts made of thermal paper expose workers and shoppers to endocrine-disrupting chemicals and contaminate paper recycling streams. In 2022, 571 receipts were collected from retail stores in the United States and tested for developer chemicals using attenuated total reflection infrared spectroscopy. The results were compared to a 2017 study of 167 receipts to determine changes in color developer use over time. Receipts were tested as-is and a subset were additionally subjected to a simple extraction that improved detection of receipt chemicals. Bisphenol S was the most frequently detected developer (85% of tested receipts), followed by Pergafast 201 (12%), bisphenol A (1%); and Appvion Alpha Free, D-8, and NKK-1304 (each below 1%). NKK-1304 is reported here for the first time in a scientific journal. The frequency of bisphenol A usage in receipts decreased and the frequency of bisphenol S and Pergafast 201 increased between 2017 and 2022, particularly among large companies. National retailers were more likely than regional or local retailers to have adopted non-bisphenol alternatives. Potential health and environmental hazards of the detected developer chemicals and strategies for reduction are discussed.

A descriptive analysis of first trimester urinary concentrations of 14 bisphenol analogues in the MIREC Canadian pregnancy cohort

BACKGROUND

Concern over the health effects of BPA, particularly for the developing fetus, has led to an increasing use of bisphenol analogues in industrial and consumer products, which may be as hormonally active as BPA. Biomonitoring data for many bisphenol analogues, especially in pregnant populations, are limited.

METHODS

We measured concentrations of 14 bisphenol analogues in 1st trimester urine samples (n = 1851) from the Maternal-Infant Research on Environmental Chemicals (MIREC) Canadian pregnancy cohort (2008-2011). We examined patterns of exposure according to sociodemographic and sampling characteristics as well as occupation and frequency of consumption of canned fish within the previous 3 months.

RESULTS

BPA was detected in 89% of participants with a specific gravity standardized geometric mean concentration of 0.990 μg/L. Biphenol 4,4' (BP 4,4'), 4,4'-dihydroxydiphenyl ether (DHDPE), and bisphenol E (BPE) were detected in >97% of participants. Bisphenol F (BPF) and bisphenol S (BPS) were detected in >60% of participants. Specific gravity standardized geometric mean concentrations of these 5 compounds ranged from 0.024 to 0.564 μg/L. Nine bisphenol analogues were detected in <9% of participants. Concentrations of BP 4,4', DHDPE, and BPE were higher in younger women and those with higher pre-pregnancy BMI, lower household income, lower education, and among smokers. We found a similar pattern of differences in BPF for age, education, and smoking status while BPS similarly differed across categories of pre-pregnancy BMI. Participants who were unemployed or working in the service industry had higher molar sum of 7 bisphenol analogues than those working in healthcare, education, or an office setting. Canned fish consumption was not related to bisphenol analogue concentrations.

CONCLUSION

BP 4,4', DHDPE, BPE, BPF, and BPS were highly detected in 1st trimester urine samples in this large pan-Canadian pregnancy cohort. This suggests widespread exposure to these analogues around 2008-2011 and warrants further investigation into associations with health outcomes.

The bisphenol S contamination level observed in human follicular fluid affects the development of porcine oocytes

Bisphenol S (BPS), the main replacement for bisphenol A (BPA), is thought to be toxic, but limited information is available on the effects of Bisphenol S on ovarian follicles. In our study, we demonstrated the presence of Bisphenol S in the follicular fluid of women at a concentration of 22.4 nM. The effect of such concentrations of Bisphenol S on oocyte maturation and subsequent embryo development is still unknown. Therefore, we focused on the effect of Bisphenol S on in vitro oocyte maturation, fertilization, and embryo development. As a model, we used porcine oocytes, which show many physiological similarities to human oocytes. Oocytes were exposed to Bisphenol S concentrations similar to those detected in female patients in the ART clinic. We found a decreased ability of oocytes to successfully complete meiotic maturation. Mature oocytes showed an increased frequency of meiotic spindle abnormalities and chromosome misalignment. Alarming associations of oocyte Bisphenol S exposure with the occurrence of aneuploidy and changes in the distribution of mitochondria and mitochondrial proteins were demonstrated for the first time. However, the number and quality of blastocysts derived from oocytes that successfully completed meiotic maturation under the influence of Bisphenol S was not affected.

Bisphenol S exposure promotes cell apoptosis and mitophagy in murine osteocytes by regulating mtROS signaling

Bisphenol S (BPS), a safer alternative to bisphenol A, is commonly used as a plasticizer to manufacture various food-packaging materials. The accumulated BPS inhibits osteoblastic bone formation and promotes osteoclastogenesis, thereby accelerating remarkable bone destruction, but it is unclear whether BPS affects osteocytes, comprising over 95% of all bone cells. This study aimed to investigate the biological effect of BPS on osteocytes in vitro, as well as the detailed mechanism. Results showed that BPS (200, 400 μmol/L) exposure caused dose-dependently cell death of osteocytes MLO-Y4, and increased cell apoptosis. BPS induced loss of mitochondrial membrane potential (MMP) and mitochondria impairment. Furthermore, BPS upregulated expressions of mitophagy-related proteins including microtubule-associated protein light chain 3 (LC-3) II and PTEN-induced putative kinase (PINK) 1, accompanied by elevation of autophagy flux and the accumulation of acidic vacuoles; whereas p62 level was downregulated after BPS treatment. Additionally, BPS triggered the production of intracellular reactive oxygen species (ROS) and mitochondrial ROS (mtROS), while it decreased expression levels of nuclear factor E2-related factor 2 (Nrf2) and quinone oxidoreductase 1 (NQO1). The specific mtROS scavenger MitoTEMPO reversed cell apoptosis and mitophagy, suggesting that mtROS contributes to BPS exposure-induced apoptosis and mitophagy in MLO-Y4 cells. Our data first provide novel evidence that apoptosis and mitophagy as cellular mechanisms for the toxic effect of BPS on osteocytes, thereby helping our understanding of the potential role of osteocytes in the adverse effect of BPS and its analogs on bone growth, and supporting strategies targeting bone destruction caused by BPS.

Occurrence of multiple bisphenol S analogues in children from Shantou, China

Emerging bisphenol S analogues (BPSs) have gained their application perspectives to replace bisphenol A (BPA) and BPA analogues (BPAs). However, the extent of human exposure and potential health risk from BPSs is rarely known yet. We hypothesized that children living in Shantou, China, a well-known e-waste recycling city, may expose to emerging BPSs together with BPA and BPAs. In this study, BPA, six commonly used BPAs and 11 emerging BPSs were determined simultaneously in 240 urine samples collected from children residing in Shantou. BPA, BPS, bisphenol F, bisphenol AF and three BPSs of 2,4'-bis(hydroxyphenyl)sulfone, 4-((4-(allyloxy)phenyl)sulfonyl)phenol and diphenylsulfone (DPS) were the urinary predominant bisphenols with detection frequencies of 67-100% in the children. BPA was found at the highest median concentration (3.36 µg/g creatinine) followed by BPS (0.313) and DPS (0.187). It is interesting to find that the girls and children in the younger group (2 ≤ age < 5) had consistently higher concentrations of the seven dominant bisphenols than the boys and these of the older group (5 ≤ age ≤ 10), respectively. The children with under/overweight suffered higher burdens of bisphenol exposure based on medians of estimated daily intakes. Association analysis results indicated that the Shantou children exposed themselves to multiple BPSs along with BPA and BPAs from assumed consumer products and/or contaminated environments.

Broadening the lens on bisphenols in coastal waters: Occurrence, partitioning, and input fluxes of multiple novel bisphenol S derivatives along with BPA and BPA analogues in the Pearl River Delta, China

Bisphenol S derivatives (BDs) are being widely used as novel substitutes for BPA and BPA analogues (BPAs), causing pollution in various environmental compartments. However, the occurrence and fate of BDs in coastal waters are currently unknown. To broaden the lens on bisphenols in coastal waters, this study measured a broad suite of 23 bisphenols, including 12 BDs along with BPA and 10 BPAs, in water, suspended particulate matter (SPM), and sediment from eight major outlets of the Pearl River Delta, China (PRD). In addition to BPA and BPAs, all the 12 BDs were detected in the collected samples. The total concentration of 12 BDs ranged from 1.2 to 25 ng/L (median of 4.3 ng/L) in water samples, 0.80-13 ng/g dw (median of 3.0 ng/g dw) in SPM samples and 0.48-3.7 ng/g dw (median of 0.64 ng/g dw) in sediment samples. For most individual BDs, they had comparable concentrations to individual BPAs. In addition, logK_d values of the frequently detected bisphenols, including BPA, BPS, BPF, 4-((4-Isopropoxyphenyl)sulfonyl)phenol (BPSIP), 2,4-bis(phenylsulfonyl)phenol (DBSP), and other 9 bisphenols, were significantly correlated with their logK_ow values (R² = 0.38, p < 0.05), indicating that the partitioning of bisphenols between the aqueous and SPM phases were strongly influenced by hydrophobic interaction. Based on bisphenols' concentrations in water from the eight outlets of PRD, the estimated input fluxes of novel BDs (1900 kg/y) were found to be even higher than that of BPAs (550 kg/y). This indicates that the riverine input of BDs into the coastal environment is gradually increasing, which should be taken seriously in the future.

Occurrence of emerging bisphenol S analogues in urine from five occupational populations in South China

Bisphenol S (BPS) and its 11 emerging analogues were investigated in 325 urine samples from five occupational populations in South China. Besides BPS, ten emerging BPS analogues were newly identified and detected in the urine. It should be noted that urinary concentrations of dominant BPS analogues of 2,4'-bis(hydroxyphenyl)sulfone (2,4-BPS), bis(3-allyl-4-hydroxyphenyl)sulfone (TGSA) and diphenylsulfone (DPS) were 1.1-2.3 times higher than that of BPS, with overall detection frequencies at 74-91 %. The median sum concentrations of the target 12 bisphenols (ng/mL) were found highest in urine from cashiers (1.12), followed by water plant staffs (0.994), teachers (0.552), doctors (0.408) and power plant staffs (0.333). The composition profile of the urinary dominant bisphenols was occupational-dependent, with 2,4-BPS accounting for 45-73 % in cashiers and power plant staffs, and with DPS and TGSA for 74-82 % among doctors, teachers and water plant staffs. Significant correlations were found among the most frequently detected bisphenols in cashiers, indicating their common application and emission pathways. The median exposures based on estimated daily intakes (EDIs, ng/kg bw/day) for the 12 bisphenols in cashiers and water plant staffs (31.6-35.6) were 1.8-3.4 times higher than those of teachers, doctors and power plant staffs (10.6-17.5). This is the first study to identify multiple emerging BPS analogues in urine from occupational populations, especially cashiers and water plant staffs.

Probing prenatal bisphenol exposures and tissue-specific DNA methylation responses in cord blood, cord tissue, and placenta

The early-gestational fetal epigenome establishes the landscape for fetal development and is susceptible to disruption via environmental stressors including chemical exposures. Research has explored how cell- and tissue-type-specific epigenomic signatures contribute to human disease, but how the epigenome in each tissue comparatively responds to environmental exposures is largely unknown. This pilot study compared DNA methylation in four previously identified genes across matched cord blood (CB), cord tissue (CT), and placental (PL) samples from 28 mother-infant pairs in tthe Michigan Mother Infant Pairs study; evaluated association between prenatal exposure to bisphenols (BPA, BPF, and BPS) and DNA methylation (DNAm) by tissue type; compared epigenome-wide DNAm of CB and PL; and explored associations between prenatal bisphenol exposures and epigenome-wide DNAm in PL. Bisphenol concentrations were quantified in first-trimester maternal urine. DNAm was assessed at four genes via pyrosequencing in three tissues; epigenome-wide DNAm analysis via Infinium MethylationEPIC array was completed on CB and PL. Candidate gene analysis revealed tissue-specific differences across all genes. In adjusted linear regression, BPA and BPF were associated with DNAm across candidate genes in PL but not CB and CT. Epigenome-wide comparison of matched CB and PL DNAm revealed tissue-specific differences at most CpG sites and modest associations between maternal first-trimester bisphenol exposures and PL but not CB DNAm. These data endorse inclusion of a variety of tissues in prenatal exposure studies. Overlapping and divergent responses in CB, CT, and PL demonstrate their utility in combination to capture a fuller picture of the epigenetic effect of developmental exposures.

Influence of living in the same home on biomonitored levels of consumer product chemicals

BACKGROUND

Individuals living in the same home may share exposures from direct contact with sources or indirectly through contamination of the home environment.

OBJECTIVE

We investigated the influence of sharing a home on urine levels of ten phenolic chemicals present in some consumer products.

METHODS

We used data from Silent Spring Institute's Detox Me Action Kit (DMAK), a crowdsourced biomonitoring program in the US. Of the 726 DMAK participants, 185 lived in the same home with one or more other DMAK participants (n = 137 pairs, up to six participants in a home). The concentration distributions included values below the detection limit so we used statistical methods that account for left-censored data, including non-parametric correlation estimation and hierarchical Bayesian regression models.

RESULTS

Concentrations were significantly positively correlated between pair-members sharing a home for nine of the ten chemicals. Concentrations of 2,5-dichlorophenol were the most strongly correlated between pair-members (tau = 0.46), followed by benzophenone-3 (tau = 0.31) and bisphenol A (tau = 0.21). The relative contribution of personal product use reported product use of other household members (up to 5 others), and the residual contribution from a shared household, including exposures not asked about, varied by chemical. Paraben concentrations were largely influenced by personal behaviors whereas dichlorophenol and bisphenol concentrations were largely influenced by shared home exposures not related to reported behaviors.

SIGNIFICANCE

Measuring the influence of personal and household practices on biomonitoring exposures helps pinpoint major sources of exposure and highlights chemical-specific intervention strategies to reduce them.

Effects of Oral Exposure to Low-Dose Bisphenol S on Allergic Asthma in Mice

Bisphenol S (BPS) is increasingly being used as an alternative for bisphenol A; however, its health effects remain unclear. We investigated the effects of oral exposure to low-dose BPS on allergic asthma. C3H/HeJ male mice were intratracheally administered with allergen (ovalbumin (OVA), 1 μg/animal) every 2 weeks from 6 to 11 weeks old. BPS was ingested by drinking water at doses equivalent to 0.04, 0.4, and 4 μg/kg/day. We then examined pulmonary inflammation, airway hyperresponsiveness, serum OVA-specific immunoglobulin (Ig) levels, Th2 cytokine/chemokine production, and mediastinal lymph node (MLN) cell activities. Compared with OVA alone, moderate-dose BPS (BPS-M) with OVA significantly enhanced pulmonary inflammation, airway hyperresponsiveness, and OVA-specific IgE and IgG1. Furthermore, interleukin (IL)-5, IL-13, IL-33, and CCL11/Eotaxin protein levels in the lungs increased. Conversely, these allergic responses were reduced in the high-dose BPS+OVA group. In MLN cells, BPS-M with OVA increased the total cell count and activated antigen-presenting cells including conventional dendritic cell subset (cDC2). After OVA restimulation, cell proliferation and Th2 cytokine production (IL-4, IL-5, and IL-13) in the culture supernatant also increased. Therefore, oral exposure to low-dose BPS may exacerbate allergic asthmatic responses by enhancing Th2-polarized responses and activating the MLN cells.

Bisphenol A in the environment and recent advances in biodegradation by fungi

Bisphenol A (BPA) is a compound used in the manufacture of a wide variety of everyday materials that, when released into the environment, causes multiple detrimental effects on humans and other organisms. The reason for this review is to provide an overview of the presence, distribution, and concentration of BPA in water, soil, sediment, and air, as well as the process of release and migration, biomagnification, and exposure mechanisms that cause various toxic effects in humans. Therefore, it is important to seek efficient and economic strategies that allow its removal from the environment and prevent it from reaching humans through food chains. Likewise, the main removal techniques are analyzed, focusing on biological treatments, particularly the most recent advances in the degradation of BPA in different environmental matrices through the use of ligninolytic fungi, non-ligninolytic fungi and yeasts, as well as the possible routes of metabolic processes that allow their biotransformation or biodegradation due to their efficient extracellular enzyme systems. This review supports the importance of the application of new biotechnological tools for the degradation of BPA.

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.

Bisphenol S Impairs Oestradiol Secretion during In Vitro Basal Folliculogenesis in a Mono-Ovulatory Species Model

Bisphenol S (BPS) affects terminal folliculogenesis by impairing steroidogenesis in granulosa cells from different species. Nevertheless, limited data are available on its effects during basal folliculogenesis. In this study, we evaluate in vitro the effects of a long-term BPS exposure on a model of basal follicular development in a mono-ovulatory species. We cultured ovine preantral follicles (180−240 μm, n = 168) with BPS (0.1 μM (possible human exposure dose) or 10 μM (high dose)) and monitored antrum appearance and follicular survival and growth for 15 days. We measured hormonal secretions (oestradiol (at day 13 [D13]), progesterone and anti-Müllerian hormone [D15]) and expression of key follicular development and redox status genes (D15) in medium and whole follicles, respectively. BPS (0.1 µM) decreased oestradiol secretion compared with the control (−48.8%, p < 0.001), without significantly impairing antrum appearance, follicular survival and growth, anti-Müllerian hormone and progesterone secretion and target gene expression. Thus, BPS could also impair oestradiol secretion during basal folliculogenesis as it is the case during terminal folliculogenesis. It questions the use of BPS as a safe BPA substitute in the human environment. More studies are required to elucidate mechanisms of action of BPS and its effects throughout basal follicular development.

Bisphenol A Analogs Induce Cellular Dysfunction in Human Trophoblast Cells in a Thyroid Hormone Receptor-Dependent Manner: In Silico and In Vitro Analyses

Bisphenol A (BPA) and its analogs are frequently detected in human daily necessities and environmental media. Placental thyroid hormone plays an important role in fetal development. Herein, we followed the adverse outcome pathway (AOP) to explore the toxic mechanisms of BPA and its analogs toward placental thyroid hormone receptor (TR). First, the TOX21 database was used, and the interactions between BPA analogs and the ligand-binding domains (LBDs) of two subtypes of TR (TRα and TRβ) were subjected to in silico screening using molecular docking (MD) and molecular dynamics simulation (MDS). Fluorescence spectra and circular dichroism (CD) showed that BPA and its analogs interfere with TRs as a molecular initiation event (MIE), including static fluorescence quenching and secondary structural content changes in TR-LBDs. Key events (KEs) of the AOP, including the toxicity induced in placental chorionic trophoblast cells (HTR-8/SVneo) by an inverted U-shaped dose effect and changes in ROS levels, were tested in vitro. BPA, BPB, and BPAF significantly changed the expression level of TRβ, and only BPAF significantly downregulated the expression level of TRα. In conclusion, our study contributes to the health risk assessment of BPA and its analogs regarding placental adverse outcomes (AOs).

Bisphenol S exposure induces intestinal inflammation: An integrated metabolomic and transcriptomic study

As a typical substitute for bisphenol A (BPA), bisphenol S (BPS) is raising concerns due to the potential adverse effects on human health. Limit evidence is available to understand the toxicity of BPS to the digestive system, especially for intestine. In this study, we aimed to investigate the potential effects and underlying mechanisms of BPS exposure on human colon mucosal epithelial cells (NCM460). Our results showed that BPS exposure significantly increased the production of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and interleukin-17A (IL-17A). The tight junctions of the cells has been destroyed by BPS exposure, which was characterized by a down-regulation of the tight junction proteins (Claudin1 and zonula occluden 1 (ZO1)). A multi-omics study explored the underlying mechanisms based on the metabolomic and transcriptomic responses. A variety of neurotransmitters increased significantly after exposure to BPS. The top enriched pathway was "glutamatergic synapse", which was activated by BPS exposure, resulting in the up-regulation of l-glutamine. Links were observed among the altered metabolites, genes and cytokines. Our results indicate that exposure to BPS may disturb the balance of gut-brain axis, leading to the production of inflammatory cytokines and the destruction of tight junction in NCM460 cells. It provides new clue for the development of intestinal inflammation in terms of the environmental pollutants.

Adverse Effects of Plasticizers and Pesticides on Female Reproductive Health

Central neuroendocrine system regulated by hypothalamus, controls most of the body homeostasis involving processes, like metabolism, reproduction, stress responsiveness, growth, and energy balance mainly through hormonal signals. Plasticizers and pesticides interact as endocrine disruptors with endocrine hormones causing adverse effects which tend to destroy the body homeostasis. Exposures to these compounds during critical developmental stages such as puberty and pregnancy (prenatal or perinatal) influence neurodevelopment, social behavior of the growing fetus and causes sexual dimorphism. Plasticizers and pesticides systemize its effects on adulthood either by mimicking, antagonizing, or having an impact on steroidal activity also along with hormonal disruptions. The aim of this review is to address some of the effects of plasticizers and pesticides exposure on female behavior. In this review, we are discussing the remedial nutritional choice to control the plasticizers and pesticides mediated endocrine disruption.

Bisphenol S exposure induces cytotoxicity in mouse Leydig cells

Bisphenol S (BPS), an increasingly used alternative to bisphenol A, has been linked to testosterone deficiency and male reproductive dysfunction in laboratory animals. This study aimed to examine the cytotoxicity of BPS exposure to Leydig cells and to investigate its possible mechanisms. After treatment with BPS (100, 200 and 400 μM) for 48 h in vitro, TM3 mouse Leydig cells exhibited a dose-dependent decrease in the viability. Furthermore, BPS challenge triggered oxidative stress manifested by compromised activities of superoxide dismutase and catalase with exaggerated formation of reactive oxygen species. Especially, BPS exposure resulted in augmented mitochondrial permeability transition pore opening, dissipated mitochondrial membrane potential and reduced ATP generation, along with an altered energy metabolism. Moreover, BPS stimulation enhanced BAX expression and caspase-3 activity and inhibited BCL-2 expression. In addition, BPS-treated TM3 cells showed an accumulation of autophagic vacuoles, together with increased Beclin1 and P62 expression and elevated LC3B-II/LC3B-I ratio. These results demonstrated that in vitro exposure to BPS exerted cytotoxicity to TM3 Leydig cells through inducing oxidative stress, mitochondrial impairment, autophagic disturbance and apoptosis.

Binding and activity of bisphenol analogues to human peroxisome proliferator-activated receptor β/δ

Several studies have indicated metabolic function disruption effects of bisphenol analogues through peroxisome proliferator-activated receptor (PPAR) alpha and gamma pathways. In the present study, we found for the first time that PPARβ/δ might be a novel cellular target of bisphenol analogues. By using the fluorescence competitive binding assay, we found seven bisphenol analogues could bind to PPARβ/δ directly, among which tetrabromobisphenol A (TBBPA, 18.38-fold) and tetrachlorobisphenol A (TCBPA, 12.06-fold) exhibited stronger binding affinity than bisphenol A (BPA). In PPARβ/δ-mediated luciferase reporter gene assay, the seven bisphenol analogues showed transcriptional activity toward PPARβ/δ. Bisphenol AF (BPAF), bisphenol F (BPF) and bisphenol B (BPB) even showed higher transcriptional activity than BPA, while TBBPA and TCBPA showed comparable activity with BPA. Moreover, in human liver HL-7702 cells, the bisphenol analogues promoted the expression of two PPARβ/δ target genes PDK4 and ANGPTL4. Molecular docking simulation indicated the binding potency of bisphenol analogues to PPARβ/δ might depend on halogenation and hydrophobicity and the transcriptional activity might depend on their binding affinity and hydrogen bond interactions. Overall, the PPARβ/δ pathway may provide a new mechanism for the metabolic function disruption of bisphenol analogues, and TBBPA and TCBPA might exert higher metabolic disruption effects than BPA via PPARβ/δ pathway.

Direct LC-MS/MS and indirect GC-MS/MS methods for measuring urinary bisphenol A concentrations are comparable

BACKGROUND

Bisphenol A (BPA) is typically measured in urine using an indirect method that involves enzymatic deconjugation and extraction. In contrast, the direct method measures free and conjugated BPA concurrently and sums them to estimate urinary BPA concentrations. Statistical comparison of total BPA results using the direct and indirect methods is necessary to accurately interpret biomonitoring data for risk assessments.

OBJECTIVES

To compare urinary BPA concentrations estimated from the indirect and direct methods in duplicate first trimester urine samples collected from 1879 pregnant women from the MIREC Study.

METHODS

For the indirect method, we measured urinary BPA concentrations using GC-MS/MS. For the direct method, we summed free and conjugated BPA concentrations measured using LC-MS/MS. We evaluated deviation between the two methods using the Bland-Altman analysis in the total sample and stratified (1) by specific gravity and (2) at the limit of quantification (LOQ).

RESULTS

Median urinary BPA concentrations for the direct and indirect methods were 0.89 µg BPA equivalents/L and 0.81 µg/L respectively. Concentrations from the direct method were, on average, 8.6% (95% CI: 6.7%, 10.5%) higher than the indirect method in a Bland-Altman analysis. The percent differences between the two methods was 4.0% in urines with specific gravities < 1.02 (n = 1348, 72%) and 20.3% in urine with specific gravity ≥ 1.02. In values below the LOQ (n = 663, 35%), we observed smaller average percent deviation (4.8%) between the two methods but wider limits of agreement.

DISCUSSION

Results from this study, based on the largest statistically rigorous comparison of the direct and indirect methods of BPA measurement, contrast previous findings reporting that the indirect method underestimates total BPA exposure. The difference in urinary BPA concentrations we observed with the indirect and direct methods is unlikely to alter the interpretation of health outcome data.

Association of Urinary Bisphenols Concentration with Asthma in Korean Adolescents: Data from the Third Korean National Environmental Health Survey

The effects of bisphenol A (BPA) on asthma have been reported in various in vitro, animal, and human epidemiologic studies. However, epidemiological studies on the effects of bisphenol S (BPS) and bisphenol F (BPF), which are substitutes of BPA, on asthma are lacking. The purpose of this study was to identify the association between BPA, BPS, and BPF and asthma. An asthma-related questionnaire; urinary BPA, BPS, BPF; and the possible confounders were analyzed among 922 adolescents aged 12–17 years who participated in the Korean National Environmental Health Survey 2016. In males, urinary BPA, BPS, and BPF did not show a significant relationship with the lifetime prevalence of asthma. In females, urinary BPS was higher in the asthma group (p < 0.01). High urinary BPS showed a significant relationship with a high odds ratio (OR) of lifetime asthma prevalence in the model adjusted for possible confounders (p < 0.05). High urinary BPS was particularly associated with an increase in the OR of asthma diagnosed after the age of 60 months (p < 0.01). Urinary BPS was significantly associated with asthma diagnosis, especially after the age of 60 months, among Korean adolescent females.

Internal exposure of Chinese children from a typical coastal city to bisphenols and possible association with thyroid hormone levels

Bisphenols (BPs) are widely used in consumer products, and human exposure to BPs is nearly ubiquitous. However, human biomonitoring data are scarce, especially for children. In this study, we quantified eight BPs in the serum of 345 children from a typical coastal city in China. Bisphenol A (BPA), bisphenol F (BPF), and bisphenol S (BPS) were frequently detected (63% BPA, 68% BPF, 43% BPS), with geometric mean (GM) concentrations of 1.6, 0.08, and 0.04 ng/mL, respectively. The other five BPs had low detection frequencies (<5%). The distribution of BPA, BPF, and BPS in children's serum samples was independent of sex whereas the concentrations of BPS and BPF both significantly increased with age (P < 0.01). The GM values of estimated daily intake for BPA and BPS were 0.61 and 0.014 μg/kg body weight (bw)/day, respectively, indicating a relatively higher exposure risk of BPA in comparison with BPS. Compared with the population with euthyroid or nonhyperthyroid thyroid dysfunction, children with hyperthyroidism suffered higher exposure to BPA. By multiple linear regression analysis, thyroid-stimulating hormone showed a significantly negative relationship with log₁₀-BPA concentration for euthyroid children (R² = 0.477, P < 0.001), whereas a significantly positive correlation (R² = 0.753, P = 0.033) was found for hyperthyroid children.

Overview of the Mechanisms of Action of Selected Bisphenols and Perfluoroalkyl Chemicals on the Male Reproductive Axes

Male fertility has been deteriorating worldwide for considerable time, with the greatest deterioration recorded mainly in the United States, Europe countries, and Australia. That is, especially in countries where an abundance of chemicals called endocrine disruptors has repeatedly been reported, both in the environment and in human matrices. Human exposure to persistent and non-persistent chemicals is ubiquitous and associated with endocrine-disrupting effects. This group of endocrine disrupting chemicals (EDC) can act as agonists or antagonists of hormone receptors and can thus significantly affect a number of physiological processes. It can even negatively affect human reproduction with an impact on the development of gonads and gametogenesis, fertilization, and the subsequent development of embryos. The negative effects of endocrine disruptors on sperm gametogenesis and male fertility in general have been investigated and repeatedly demonstrated in experimental and epidemiological studies. Male reproduction is affected by endocrine disruptors via their effect on testicular development, impact on estrogen and androgen receptors, potential epigenetic effect, production of reactive oxygen species or direct effect on spermatozoa and other cells of testicular tissue. Emerging scientific evidence suggests that the increasing incidence of male infertility is associated with the exposure to persistent and non-persistent endocrine-disrupting chemicals such as bisphenols and perfluoroalkyl chemicals (PFAS). These chemicals may impact men’s fertility through various mechanisms. This study provides an overview of the mechanisms of action common to persistent (PFAS) and nonpersistent (bisphenols) EDC on male fertility.

Concentration-dependent transcriptome of zebrafish larvae for environmental bisphenol S assessment

The widespread use of bisphenol S (BPS) as an alternative to bisphenol A has captured attention due to its potential toxicity to aquatic organisms. In the present study, the zebrafish was used as a model to evaluate the toxicity of BPS and determine the underlying mechanisms. The environmental concentration-dependent (0, 0.1, 1, 10, 100, and 1000 μg/L BPS) transcriptome approach was employed in combination with toxicity assays to address the problem. Based on a weighted correlation network analysis, we speculated that excess reactive oxygen species (ROS) may initiate cellular events in BPS-exposed zebrafish, leading to multiple toxic effects. Furthermore, we used pathway enrichment analysis to identify key pathways (MAPK signalling pathway and metabolic pathways) that link the molecular mechanisms with different toxic effects. In addition, we performed protein-protein network and shortest path analyses to identify six hub genes (erbb2, rrm2, rps27a, his2h3c, cdk1, and mcm5) and their interactions. Moreover, we suggest that BPS may interact with erbb2 by molecular docking. Thus, the BPS-erbb2 interaction may activate the MAPK signalling and metabolic pathways, resulting in ROS production and then caused multiple toxic effects in zebrafish. This study provides information for characterising the mechanisms of BPS exposure in aquatic environments.

Intestinal toxicity and microbial community disorder induced by bisphenol F and bisphenol S in zebrafish

The intestine is the important bioaccumulation and target organ of Bisphenol F (BPF) and Bisphenol S (BPS). Morphological and functional abnormalities induced by BPS and BPF exposure in zebrafish intestine have been reported. However, the underlying mechanisms are not well understood, and the combined toxicities of BPS and BPF in the intestine have not been studied. Here, the zebrafish were treated by single and combined exposure of BPF and BPS at 1, 10, 100, 1000 μg/L. Oxidative damage, inflammation, and transcriptome profiles in the zebrafish intestine were determined. Changes in microbial community structure in zebrafish intestine were analyzed. Results showed that BPF, BPS, and BPF + BPS exposures significantly increased MDA, 8-OHdG, 1L-1β, and TNF-α levels in the zebrafish intestine, indicating oxidative damage and inflammatory effects. Co-exposure of BPS and BPF did not cause synergistic effects on the above effects but induced more changes in gene expression profiles. The changes in the PPAR signaling pathway might be associated with oxidative damage and inflammation. The amino acid metabolism and steroid biosynthesis were specifically altered by co-exposure of BPF and BPS. Moreover, BPF and/or BPS exposures altered microbial community structure in the zebrafish intestine, which showed different influence patterns. Increased abundance of potentially pathogenic bacteria (such as Flavobacterium, Pseudomonas, and Stenotrophomonas) might indicate one of the potential health hazards in zebrafish intestine. The above results provide basic information for the health risk assessment of BPS and BPF in aquatic organisms.

Drivers of owning more BPA

Bisphenol A (BPA) is a ubiquitous environmental toxin worldwide. Despite the many studies documenting the toxicity of this substance, it remains a popular choice for consumer products. The internet, magazine articles, and newspaper reports are replete with tips on how to avoid BPA exposure, which mostly spread contradictory and often unscientific information. Therefore, based on a comprehensive search of the available biomedical literature, we summarized several confounding factors that may be directly or indirectly related to human BPA exposure. We found that the unique properties of BPA materials (i.e. low cost, light-weight, resistance to corrosion, and water/air-tightness), lack of personal health and hygiene education, fear of BPA-substitutes (with yet unknown risks), inappropriate production, processing, and marketing of materials containing BPA, as well as the state of regulatory guidance are influencing the increased exposure to BPA. Besides, we detailed the disparities between scientifically derived safe dosages of BPA and those designated as "safe" by government regulatory agencies. Therefore, in addition to providing a current assessment of the states of academic research, government policies, and consumer behaviors, we make several reasonable and actionable recommendations for limiting human exposure to BPA through improved labeling, science-based dosage limits, and public awareness campaigns.

Biomonitoring of occupational exposure to bisphenol A, bisphenol S and bisphenol F: A systematic review

Bisphenol A (BPA) and its substitutes bisphenol S (BPS) and bisphenol F (BPF) are endocrine disrupting chemicals widely used in the production of polycarbonate plastics, epoxy resins and thermal papers. The aim of the review was to identify occupational studies using human biomonitoring (HBM) as a tool for bisphenol exposure assessment and to characterize research gaps on the topic as part of the HBM4EU project. Hence, a systematic literature search using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was conducted for articles published between 2000 and 27th March 2020 across three databases (PubMed, Scopus and Web of Science). Thirty studies on the occupational HBM of BPA met the inclusion criteria. Regarding BPS and BPF, only 4 and 2 publications were retrieved, respectively. Fifty-seven percent (57%) of the studies selected for BPA were conducted in Asia whereas half of BPS and BPF studies were undertaken in Europe. Studies on BPA in plastic and epoxy resin sectors were infrequent in Europe while Asian data showed higher exposure when the substance is employed as raw material. The main data on BPS were among cashiers while BPF data were available from incinerator workers. Several research gaps have been identified: (i) shortage of HBM studies on occupational exposure, especially to BPS and BPF; (ii) different methodological designs making suitable comparisons between studies difficult; and (iii) only few studies conducted on the industrial applications of bisphenols outside Asia. This review highlights the lack of recent occupational HBM studies on bisphenols and the need for a harmonized approach to acquire reliable data. Considering the increasing replacement of BPA by BPS and BPF, it is of relevance to evaluate the exposure to these substances and the impact of the available risk management measures on workers exposure and possible health risk.

Breast cancer proliferation and deterioration-associated metabolic heterogeneity changes induced by exposure of bisphenol S, a widespread replacement of bisphenol A

Exposure to bisphenol A (BPA) is considered to be associated with the increased incidence of breast cancer. As a widespread replacement of BPA, the effect of bisphenol S (BPS) on breast tumor programming has not been studied. We reported that BPS exposure significantly promoted proliferation and deterioration of breast tumor by nonmonotonic dose response. The mechanisms were investigated by molecular biology and mass spectrometry-based lipidomics, proteomics and imaging. BPS exposure induced the spatially intratumor heterogeneity of morphology-driven lipids and proteins. The more significant proliferation resulted from BPS-10 (10 μg/kg body weight /day) exposure was evidenced by the variations of spatial distribution of lipids related to ceramide-sphingomyelin signaling pathway, proteins related to chromosomal stability and cell proliferation in central necrotic regions of breast tumor. In contrast, the BPS-100 exposure obviously accelerated deterioration of breast tumor by the variations of spatial distribution of proteins that were associated with the stability of nucleic acid structure in peripheral neoplastic regions. Accordingly, dysregulation of metabolism and protein function as well as DNA methylation and hypoxic tumor microenvironment could be applied to predict the possibility of tumorigenesis, proliferation and metastasis that might be caused by other bisphenol analogs.

Bisphenol S is present in culture media used for ART and cell culture

STUDY QUESTION

Do plastic laboratory consumables and cell culture media used in ART contain bisphenols?

SUMMARY ANSWER

The majority of human embryo culture media assessed contained bisphenol S close to the nanomolar concentration range, while no release of bisphenols by plastic consumables was detected under routine conditions.

WHAT IS KNOWN ALREADY

The deleterious effect of the endocrine disruptor bisphenol A (BPA) on female fertility raised concerns regarding ART outcome. BPA was detected neither in media nor in the majority of plastic consumables used in ART; however, it might have already been replaced by its structural analogs, including bisphenol S (BPS).

STUDY DESIGN, SIZE, DURATION

Seventeen plastic consumables and 18 cell culture and ART media were assessed for the presence of bisphenols.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ten different bisphenols (bisphenol A, S, AF, AP, B, C, E, F, P and Z) were measured using an isotopic dilution according to an on-line solid phase extraction/liquid chromatography/mass spectrometry method.

MAIN RESULTS AND THE ROLE OF CHANCE

While the plastic consumables did not release bisphenols under routine conditions, 16 of the 18 cell culture and ART media assessed contained BPS. Six media exhibited BPS concentrations higher than 1 nM and reached up to 6.7 nM (1693 ng/l).

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Further studies are required to investigate a greater number of ART media to identify less potentially harmful ones, in terms of bisphenol content.

WIDER IMPLICATIONS OF THE FINDINGS

As BPS has already been reported to impair oocyte quality at nanomolar concentrations, its presence in ART media, at a similar concentration range, could contribute to a decrease in the ART success rate. Thus far, there has been no regulation of these compounds in the ART context.

STUDY FUNDING/COMPETING INTERESTS

This study was financially supported by the ‘Centre-Val de Loire’ Region (Bemol project, APR IR 2017), INRAE, BRGM, the French National Research Agency (project ANR-18-CE34-0011-01 MAMBO) and the BioMedicine Agency (Project 18AMP006 FertiPhenol). The authors declare that they have no conflict of interest that could be perceived as prejudicing the impartiality of the reported research.

Low doses of BPF-induced hypertrophy in cardiomyocytes derived from human embryonic stem cells via disrupting the mitochondrial fission upon the interaction between ERβ and calcineurin A-DRP1 signaling pathway

Bisphenol F (BPF) is a replacement to bisphenol A, which has been extensively used in industrial manufacturing. Its wide detection in various human samples raises increasing concern on its safety. Currently, whether a low dose of BPF compromises cardiac function is still unknown. This study provides the first evidence that low-dose BPF can induce cardiac hypertrophy by using cardiomyocytes derived from human embryonic stem cells (hES). Non-cytotoxic BPF increased cytosolic Ca 2+ influx ([Ca2+ ]c), which was most remarkable at low dose (7 ng/ml) rather than at higher doses. Significant changes in the morphological parameters of mitochondria and significant decreases in ATP production were induced by 7 ng/ml BPF, representing a classic hypertrophic cardiomyocyte. After eliminating the direct effects on mitochondrial fission-related DRP1 by administration of the DRP1 inhibitor Mdivi-1, we examined the changes in [Ca 2+ ]c levels induced by BPF, which enhanced the calcineurin (Cn) activity and induced the abnormal mitochondrial fission via the CnAβ-DRP1 signaling pathway. BPF triggered excessive Ca 2+ influx by disrupting the L-type Ca 2+channel in cardiomyocytes. The interaction between ERβ and CnAβ cooperatively involved in the BPF-induced Ca 2+ influx, which resulted in the abnormal mitochondrial fission and compromised the cardiac function. Our findings provide a feasible molecular mechanism for explaining low-dose BPF-induced cardiac hypertrophy in vitro, preliminarily suggesting that BPF may not be as safe as assumed in humans.

Skin Absorption of Bisphenol A and Its Alternatives in Thermal Paper

OBJECTIVES

Bisphenol A (BPA) is the most used colour developer in thermal paper for cashiers receipts, labels, and tickets. BPA can migrate onto the skin and be absorbed when handling these papers. BPA is a known endocrine disruptor and is therefore being replaced in thermal paper by some alternatives such as Bisphenol S (BPS), D-8, and Pergafast 201® (PF201). To our knowledge, no studies have characterized skin permeation of these BPA alternatives.

METHODS

We measured/characterized skin absorption for BPA, BPS, D-8, and PF201 through ex vivo human skin using flow-through diffusion cells according to OECD guideline 428. Skin samples were 7-12 per test substance from three different skin donors. Skin metabolism was studied for BPA. Dermal absorption was expressed as the amount of the BPA alternatives in the receptor fluid over applied dose in percent (%).

RESULTS

The absorbed dose after 24 h of exposure was 25% for BPA, 17% for D-8, 0.4% for BPS, and <LLOQ for PF201. The amount of BPA-glucuronide in the receptor fluid after 24 h was under the limit of quantification (LLOQ = 0.2 µg l-1). Despite the 10-fold lower concentration of the aq solution applied on the skin, D-8's permeation rate JMAX was 5-fold higher than the one for BPS (0.032 versus 0.006 µg cm-2 h-1). Neither D-8 nor BPS permeated readily through the skin (tlag = 3.9 h for D-8, 6.4 h for BPS). None of PF201's skin permeation kinetic parameters could be determined because this BPA analogue was not quantifiable in the receptor fluid in our test conditions.

CONCLUSIONS

Skin absorption was in decreasing order: BPA > D-8 >> BPS > PF201. These results are in agreement with their log Kow and molecular weights. We provided here the necessary data to estimate the extent of skin absorption of BPA analogues, which is a necessary step in risk assessment, and ultimately evaluate public health risks posed by D-8, BPS, and PF201.

Exposure to alternative bisphenols BPS and BPF through breast milk: Noxious heritage effect during nursing associated with idiopathic infertility

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

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 [Cmax/D (ng/mL)/(ppm)] and area under the concentration time curve [AUC/D (h × ng/mL)/(ppm)] for free was higher for BPS (Cmax/D: 0.476-1.02; AUC/D: 3.58-8.26) than for BPAF (Cmax/D: 0.017-0.037; AUC/D:0.196-0.436). In mice, the difference in systemic exposure parameters between free BPS (Cmax/D: 0.376-0.459; AUC/D: 1.52-2.54) and free BPAF (Cmax/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.

Development and Validation of an Analytical Method for Quantitation of Bisphenol S in Rodent Plasma, Amniotic Fluid and Fetuses by UPLC-MS-MS

Bisphenol S (BPS) has been detected in personal care products, water, food and indoor house dust, demonstrating the potential for human exposure. Due to limited data to characterize the hazard of BPS, the National Toxicology Program (NTP) is investigating the toxicity of BPS in rodent models. Generating systemic exposure data is integral to putting toxicological findings into context. The objective of this work was to develop and validate a method to quantitate free (unconjugated parent) and total (free and all conjugated forms of) BPS in rodent plasma, amniotic fluid and fetal homogenate in support of NTP studies. The method used incubation with (total BPS) and without (free BPS) deconjugating enzyme and then protein precipitation followed by ultra-performance liquid chromatography-tandem mass spectrometry. In Sprague Dawley rat plasma, the method was linear (r ≥ 0.99) over the range 5-1,000 ng/mL, accurate (mean relative error (RE) ≤ ±10.5%) and precise (relative standard deviation (RSD) ≤ 7.7%). Mean recoveries were ≥93.1% for both free and total analyses. The limits of detection were 1.15 ng/mL (free) and 0.862 ng/mL (total) in plasma. The method was evaluated in the following study matrices: (i) male Hsd:Sprague Dawley®SD® (HSD) rat plasma, (ii) female HSD rat plasma, (iii) male B6C3F1 mouse plasma, (iv) female B6C3F1 mouse plasma, (v) HSD rat gestational day (GD) 18 dam plasma, (vi) HSD rat GD 18 amniotic fluid, (vii) HSD rat GD 18 fetal homogenate and (viii) HSD rat postnatal day 4 pup plasma (mean %RE ≤ ±8.2 and %RSD ≤ 8.7). Stability of BPS in extracted samples was demonstrated for up to 7 days at various temperatures, and freeze-thaw stability was demonstrated after three cycles over 7 days. BPS in various matrices stored at -80°C for at least 60 days was within 92.1-115% of Day 0 concentrations, demonstrating its stability in these matrices. These data demonstrate that this simple method is suitable for determination of free and total BPS in plasma, amniotic fluid and fetuses following exposure of rodents to BPS.

Pharmacokinetics of bisphenol A in humans following dermal administration

BACKGROUND

Human exposures to bisphenol A (BPA) are widespread. The current study addresses uncertainties regarding human pharmacokinetics of BPA following dermal exposure.

OBJECTIVE

To examine the absorption, distribution, metabolism and excretion of BPA in humans following dermal administration.

METHODS

We dermally administered deuterated BPA (d6-BPA) to 10 subjects (6 men and 4 women) at a dose of 100 µg/kg over a 12-hour period and conducted blood and urine analysis from the beginning of dosing through a three- or six-day period. We present time-course serum and urine concentrations of total and unconjugated ("free") d6-BPA and used this information to calculate terminal half-life and area under the curve.

RESULTS AND CONCLUSIONS

Detectable serum levels of total d6-BPA were observed at 1.4 h after the start of dosing, and a maximum serum concentration (C_max) of 3.26 nM was observed. Free d6-BPA was detectable in serum 2.8 h after start of dermal administration, with C_max of 0.272 nM. Beginning at approximately seven hours and continuing to 12 h (which corresponds to cessation of exposure), the concentration of free and total serum d6-BPA plateaued. The terminal half-lives of total d6-BPA and free d6-BPA in the body were 21.4 ± 9.81 h and 17.6 ± 7.69 h, respectively. Elimination from the body was rate-limited by kinetics in the dermal compartment. Free d6-BPA was a greater percentage of the area under the curve of total serum BPA (8.81%) compared to the 0.56% observed in our previously published oral study. Recovery of total d6-BPA in urine was <2% of the applied dose after six days. Analysis of the area under the curve for dermal and oral administration revealed that 2.2% of the dermal dose became systemically available. These data are in line with prior studies indicating how pharmacokinetics of BPA differ following oral and dermal exposures. Dermal exposure resulted in a longer apparent half-life and higher free:total d6-BPA ratio compared to oral.

Evaluation of bisphenol A levels in Nigerian thermal receipts and estimation of daily dermal exposure

Bisphenol A (BPA) is a high production volume chemical that has wide industrial applications, especially as a color developer in thermal papers. The present study focused on the determination of levels of BPA in thermal receipts collected from different locations in Akure, Nigeria, and the estimation of daily intake of BPA through dermal absorption. Thermal receipts were collected from different locations, and the levels of extracted BPA were determined using fluorescence spectroscopy. The daily intake of BPA was estimated, and the amount was compared with the reference value. BPA was detected in all the samples analyzed with levels ranging from 1.50 to 3.16 mg/g. These values were lower than the values detected in thermal receipts obtained from other countries. The estimated mean daily intakes of BPA by dermal absorption due to handling of thermal receipts were 0.20 and 9.89 μg/day for the general population and the occupationally exposed individuals, respectively, and were much lower than the reference value of 50 μg/kg bw/day provided by the European Food Safety Authority. This indicates that dermal exposure to BPA is not a serious health risk to the population.

Comparative toxicokinetics of bisphenol S in rats and mice following gavage administration

Bisphenol S (BPS) is a component of polyether sulfone used in a variety of industrial applications and consumer products. We investigated the plasma toxicokinetic (TK) behavior of free (unconjugated parent) and total (parent and conjugated) BPS in rats and mice following a single gavage administration (34, 110, or 340 mg/kg). In male rats, BPS was rapidly absorbed with free BPS maximum concentration (C_max) reached at ≤2.27 h. Elimination of free BPS in male rats was dose-dependent with estimated half-lives of 5.77-11.9 h. C_max and area under the concentration versus time curve (AUC) increased with dose although the increase in AUC was more than dose proportional. In male rats, total BPS C_max was reached ≤2.77 h with both C_max (≥ 10-fold) and AUC (≥ 15-fold) higher than free BPS demonstrating rapid and extensive conjugation of BPS. In male mice, the increase in C_max and AUC of free BPS was dose-proportional; C_max was higher and AUC was lower than in male rats. BPS was cleared more rapidly in male mice (half-life 2.86-4.21 h) compared to male rats (half-life 5.77-11.9 h). Similar to rats, total BPS C_max (≥ 6-fold) and AUC (≥ 12-fold) were higher than corresponding free BPS. Oral bioavailability of free BPS was low to moderate (rats, ≤ 21%; mice, ≤ 19%). There were some species differences in TK parameters of free and total BPS and limited sex difference in rats and mice. In addition, there were dose-related effects of plasma TK parameters in rats.