Bisphenol A and its analogs: Do their metabolites have endocrine activity?

Wastewater-based epidemiology methodology to investigate human exposure to bisphenol A, bisphenol F and bisphenol S

Wastewater-based epidemiology (WBE) has become an invaluable tool for tracking the evolution of use or exposure of/to numerous substances. Bisphenols, commonly utilized in manufacturing plastic goods, have been categorized as endocrine disrupting chemicals, underscoring the critical need for real-time data on their local-level exposure to safeguard public health. In this study, we have developed a novel analytical method and WBE framework for the assessment of population-level exposure to bisphenol A (BPA) and its most prominent substitutes, bisphenols F and S (BPF and BPS), through the determination their Phase II metabolites in wastewater by WBE. Stability and exclusivity tests denoted that glucuronides are not stable in sewage, whereas sulfate metabolites are good biomarkers. Therefore, a solid-phase extraction followed by liquid chromatography-tandem mass spectrometry method was developed for the bisphenols' monosulfates and BPA bissulfate. The analytical method was validated with three different wastewater matrices, providing trueness (as recovery) in the 79-112 % range with relative standard deviations < 12 %, and method quantification limits below 2 ng L-1 for monosulfates, but higher (35 ng L-1) for BPA bissulfate. Subsequently, the method was applied to 24h-composite raw wastewater samples collected over a week in 4 different locations in Spain and Portugal. BPA bissulfate was not detected, but the three monosulfate metabolites of each bisphenol were positively detected in the samples, being the metabolite of BPA the most prevalent, followed by those of BPF and BPS. Community-wide BPA intake was then estimated to be higher than the European Food Safety Agency (EFSA) tolerable daily intake (TDI) of 2 × 10-4 µg kg-1day-1 in all locations. In the case of BPF and BPS, there is not enough metabolism data or even established limit, but they would also surpass safe levels in several locations if a similar metabolism and TDI would be assumed. This innovative method could be used to a larger set of wastewater-treatment plants as an early-warning approach on human exposure to bisphenols.

Exploring the relationships between exposure levels of bisphenols and phthalates and prostate cancer occurrence

We established an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for simultaneously analyzing the metabolites of bisphenols and phthalates in urine to identify the associations between these exposure levels and prostate cancer (PCa) based on a case-control study. After purifying urine samples with SPE, 18 metabolites were separated on a C18 column, and MS detection was performed. The UPLC-MS/MS method has been proven effective at evaluating bisphenol and phthalate exposure (0.020-0.20 μg/L of the limits of detection, 71.8 %∼119.4 % of recoveries, 0.4 %∼8.2 % of precision). Logistic regression explored the association between exposure level and PCa in 187 PCa cases and 151 controls. The detection rates of bisphenol A (BPA) and most phthalate metabolites were 100 % ranging from 0.06-46.74 and 0.12-899.92 μg/g creatinine, respectively, while the detection rates of other bisphenols and mono-benzyl phthalate (MBzP) are low, ranging from 0 % to 21.85 %. Correlation analysis of the metabolite levels indicated that the exposure sources of BPA, di-ethyl phthalate (DEP), and di(2-ethylhexyl) phthalate (DEHP) were different, and that the exposure sources of di-n-butyl phthalate (DnBP) and di-isobutyl phthalate (DiBP) may differ between two groups. Logistic regression analysis revealed that BPA (OR<0.45 vs ≥1.43 =10.02) and DEHP exposure (OR<21.75 vs ≥45.42 =48.26) increased the risk of PCa.

Interaction of Bisphenol A and Its Analogs with Estrogen and Androgen Receptor from Atlantic Cod (Gadus morhua)

The widespread use of bisphenol A (BPA) in polycarbonate plastics and epoxy resins has made it a prevalent environmental pollutant in aquatic ecosystems. BPA poses a significant threat to marine and freshwater wildlife due to its documented endocrine-disrupting effects on various species. Manufacturers are increasingly turning to other bisphenol compounds as supposedly safer alternatives. In this study, we employed in vitro reporter gene assays and ex vivo precision-cut liver slices from Atlantic cod (Gadus morhua) to investigate whether BPA and 11 BPA analogs exhibit estrogenic, antiestrogenic, androgenic, or antiandrogenic effects by influencing estrogen or androgen receptor signaling pathways. Most bisphenols, including BPA, displayed estrogenic properties by activating the Atlantic cod estrogen receptor alpha (gmEra). BPB, BPE, and BPF exhibited efficacy similar to or higher than that of BPA, with BPB and BPAF being more potent agonists. Additionally, some bisphenols, like BPG, induced estrogenic effects in ex vivo liver slices despite not activating gmEra in vitro, suggesting structural modifications by hepatic biotransformation enzymes. While only BPC2 and BPAF activated the Atlantic cod androgen receptor alpha (gmAra), several bisphenols exhibited antiandrogenic effects by inhibiting gmAra activity. This study underscores the endocrine-disrupting impact of bisphenols on aquatic organisms, emphasizing that substitutes for BPA may pose equal or greater risks to both the environment and human health.

Critical role of endoplasmic reticulum stress on bisphenol A-induced cytotoxicity in human keratinocyte HaCaT cells

Bisphenol A (BPA) is widely used in plastic and paper products, and its exposure can occur through skin contact or oral ingestion. The hazardous effects of BPA absorbed through the skin may be more severe; however, few studies have investigated the skin toxicity of BPA. This study investigated the effects of BPA on human epidermal keratinocyte cell lines, which is relevant for skin exposure. BPA treatment reduced cell viability in a time- and concentration-dependent manner and elevated oxidative and endoplasmic reticulum (ER) stress. N-acetylcysteine (NAC), an oxidative stress inhibitor, reduced BPA-induced reactive oxygen species (ROS) levels. However, only 10% of the decreased cell viability was restored at the highest NAC concentration. Treatment with tauroursodeoxycholic acid (TUDCA), which is an ER stress inhibitor, effectively countered the increase in ER stress-related proteins induced by BPA. Moreover, TUDCA treatment led to a reduction in oxidative stress, as demonstrated by the decrease in ROS levels, maintenance of mitochondrial membrane potential, and modulation of stress signaling proteins. Consequently, TUDCA significantly improved BPA-induced cytotoxicity in a concentration-dependent manner. Notably, combined treatment using TUDCA and NAC further reduced the BPA-induced ROS levels; however, no significant difference in cell viability was observed compared with that for TUDCA treatment alone. These findings indicated that the oxidative stress observed following BPA exposure was exacerbated by ER stress. Moreover, the principal factor driving BPA-induced cytotoxicity was indeed ER stress, which has potential implications for developing therapeutic strategies for diseases associated with similar stress responses.

Determination of the urinary concentrations of six bisphenols in public servants by online solid-phase extraction-liquid chromatography tandem mass spectrometry

Bisphenols are widely used as monomers and additives in plastic production. Thus, bisphenol A (BPA) and its most prominent substitutes have been detected in many environmental and human samples. This study proposes an online solid-phase extraction analytical methodology coupled to liquid chromatography with tandem mass spectrometry for the determination of six bisphenols (BPA and bisphenols F (BPF), S (BPS), AF (BPAF), B (BPB), and E (BPE)) in urine samples as an efficient and automated methodology. The method was developed and validated for all bisphenols with good recoveries (92-112%) and repeatability (RSD ≤ 10%) despite the variable matrix effects, except BPAF (which would require a dedicated internal standard), achieving method quantification limits in the 0.05-2.2 ng mL-1 range. The methodology was subsequently applied to 435 urine samples from a non-occupational exposure population (civil servants for the regional government) from Santiago de Compostela (Galicia, Spain). Only BPA, BPF, and BPS were positively detected; the last two presented higher detection frequencies than BPA. When the urinary concentrations are extrapolated to human intake and compared to the European Food Safety Agency (EFSA) tolerable daily intake (TDI) of 2 × 10-4 µg kg-1 day-1 (TDI), all BPA positively identified samples would surpass this threshold. Although no TDI exists currently for the other two identified bisphenols, it is evident that human exposure to bisphenols should be limited. Finally, the results stratification by gender revealed higher levels of exposure to BPF in the women group.

Metabolic activity of gut microbial enrichment cultures from different marine species and their transformation abilities to plastic additives

The role of the gut microbiota in host physiology has been previously elucidated for some marine organisms, but little information is available on their metabolic activity involved in transformation of environmental pollutants. This study assessed the metabolic profiles of the gut microbial cultures from grouper (Epinephelus coioides), green mussel (Perna viridis) and giant tiger prawn (Penaeus monodon) and investigated their transformation mechanisms to typical plastic additives. Community-level physiological profiling analysis confirmed the utilization profiles of the microbial cultures including carbon sources of carbohydrates, amines, carboxylic acids, phenolic compounds, polymers and amino acids, and the plastic additives of organophosphate flame retardants, tetrabromobisphenol A derivates and bisphenols. Using in vitro incubation, triphenyl phosphate (TPHP) was found to be rapidly metabolized into diphenyl phosphate by the gut microbiota as a representative ester-containing plastic additive, whereas the transformation of BPA (a representative phenol) was relatively slower. Interestingly, all three kinds of microbial cultures efficiently transformed the hepatic metabolite of BPA (BPA-G) back to BPA, thereby increasing its bioavailability in the body. The specific enzyme analysis confirmed the ability of the gut microbiota to perform the metabolic reactions. The results of 16S rRNA sequencing and network analysis revealed that the genera Escherichia-Shigella, Citrobacter, and Anaerospora were functional microbes, and their collaboration with fermentative microbes played pivotal roles in the transformation of the plastic additives. The structure-specific transformations by the gut microbiota and their distinct bioavailability deserve more attention in the future.

Update of the scientific opinion on tetrabromobisphenol A (TBBPA) and its derivatives in food

The European Commission asked EFSA to update its 2011 risk assessment on tetrabromobisphenol A (TBBPA) and five derivatives in food. Neurotoxicity and carcinogenicity were considered as the critical effects of TBBPA in rodent studies. The available evidence indicates that the carcinogenicity of TBBPA occurs via non-genotoxic mechanisms. Taking into account the new data, the CONTAM Panel considered it appropriate to set a tolerable daily intake (TDI). Based on decreased interest in social interaction in male mice, a lowest observed adverse effect level (LOAEL) of 0.2 mg/kg body weight (bw) per day was identified and selected as the reference point for the risk characterisation. Applying the default uncertainty factor of 100 for inter- and intraspecies variability, and a factor of 3 to extrapolate from the LOAEL to NOAEL, a TDI for TBBPA of 0.7 μg/kg bw per day was established. Around 2100 analytical results for TBBPA in food were used to estimate dietary exposure for the European population. The most important contributors to the chronic dietary LB exposure to TBBPA were fish and seafood, meat and meat products and milk and dairy products. The exposure estimates to TBBPA were all below the TDI, including those estimated for breastfed and formula-fed infants. Accounting for the uncertainties affecting the assessment, the CONTAM Panel concluded with 90%-95% certainty that the current dietary exposure to TBBPA does not raise a health concern for any of the population groups considered. There were insufficient data on the toxicity of any of the TBBPA derivatives to derive reference points, or to allow a comparison with TBBPA that would support assignment to an assessment group for the purposes of combined risk assessment.

An in vitro model system for testing chemical effects on microbiome-immune interactions - examples with BPX and PFAS mixtures

Introduction

More than 350,000 chemicals make up the chemical universe that surrounds us every day. The impact of this vast array of compounds on our health is still poorly understood. Manufacturers are required to carry out toxicological studies, for example on the reproductive or nervous systems, before putting a new substance on the market. However, toxicological safety does not exclude effects resulting from chronic exposure to low doses or effects on other potentially affected organ systems. This is the case for the microbiome-immune interaction, which is not yet included in any safety studies.

Methods

A high-throughput in vitro model was used to elucidate the potential effects of environmental chemicals and chemical mixtures on microbiome-immune interactions. Therefore, a simplified human intestinal microbiota (SIHUMIx) consisting of eight bacterial species was cultured in vitro in a bioreactor that partially mimics intestinal conditions. The bacteria were continuously exposed to mixtures of representative and widely distributed environmental chemicals, i.e. bisphenols (BPX) and/or per- and polyfluoroalkyl substances (PFAS) at concentrations of 22 µM and 4 µM, respectively. Furthermore, changes in the immunostimulatory potential of exposed microbes were investigated using a co-culture system with human peripheral blood mononuclear cells (PBMCs).

Results

The exposure to BPX, PFAS or their mixture did not influence the community structure and the riboflavin production of SIHUMIx in vitro. However, it altered the potential of the consortium to stimulate human immune cells: in particular, activation of CD8+ MAIT cells was affected by the exposure to BPX- and PFAS mixtures-treated bacteria.

Discussion

The present study provides a model to investigate how environmental chemicals can indirectly affect immune cells via exposed microbes. It contributes to the much-needed knowledge on the effects of EDCs on an organ system that has been little explored in this context, especially from the perspective of cumulative exposure.

Research progress of the effects of bisphenol analogues on the intestine and its underlying mechanisms: A review

Bisphenol A (BPA) and its analogues have prompted rising concerns, especially in terms of human safety, due to its broad use and ubiquity throughout the ecosystem. Numerous studies reported various adverse effects of bisphenols, including developmental disorders, reproductive toxicity, cardiovascular toxicity, and so on. There is increasing evidence that bisphenols can enter the gastrointestinal tract. Consequently, it is important to investigate their effects on the intestine. Several in vivo and in vitro studies have examined the impacts of bisphenols on the intestine. Here, we summarized the literature concerning intestinal toxicity of bisphenols over the past decade and presented compelling evidence of the link between bisphenol exposure and intestinal disorders. Experiment studies revealed that even at low levels, bisphenols could promote intestinal barrier dysregulation, disrupt the composition and diversity of intestinal microbiota as well as induce an immunological response. Moreover, possible underlying mechanisms of these effects were discussed. Because of a lack of empirical data, the potential risk of bisphenol exposure in humans is still unidentified, particularly regarding intestinal disorders. Thus, we propose to conduct additional epidemiological investigations and animal experiments to elucidate the associations between bisphenol exposure and human intestinal health and reveal underlying mechanisms to develop preventative and therapeutic techniques.

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.

Perinatal exposure to bisphenol A or S: Effects on anxiety-related behaviors and serotonergic system

Bisphenols, synthetic organic compounds used in the production of plastics, are an extremely abundant class of Endocrine Disrupting Chemicals, i.e., exogenous chemicals or mixtures of chemicals that can interfere with any aspect of hormone action. Exposure to BPs can lead to a wide range of effects, and it is especially dangerous if it occurs during specific critical periods of life. Focusing on the perinatal exposure to BPA or its largely used substitute BPS, we investigated the effects on anxiety-related behaviors and the serotonergic system, which is highly involved in controlling these behaviors, in adult mice. We treated C57BL/6J dams orally with a dose of 4 μg/kg body weight/day (i.e., EFSA TDI) of BPA or BPS dissolved in corn oil or with vehicle alone, at the onset of mating and continued treatment until the offspring were weaned. Adult offspring of both sexes performed the elevated plus maze and the open field tests. Then, we analyzed the serotonergic system in dorsal (DR) and median (MnR) raphe nuclei by immunohistochemical techniques. Behavioral tests highlighted alterations in BPA- and BPS-treated mice, suggesting different effects of the bisphenols exposure on anxiety-related behavior in males (anxiolytic) and females (anxiogenic). The analysis of the serotonergic system highlighted a sex dimorphism in the DR only, with control females showing higher values of serotonin immunoreactivity (5-HT-ir) than control males. BPA-treated males displayed a significant increase of 5-HT-ir in all analyzed nuclei, whereas BPS-treated males showed an increase in ventral DR only. In females, both bisphenols-treated groups showed a significant increase of 5-HT-ir in dorsal DR compared to the controls, and BPA-treated females also showed a significant increase in MnR.These results provide evidence that exposure during the early phases of life to BPA or BPS alters anxiety and the raphe serotonergic neurons in a sex-dependent manner.

Potential impacts of bisphenols on prostate cells: An overview of cytotoxicity, proliferation, oxidative stress, apoptosis, and ER-stress response activation

This study aimed to evaluate the toxic effects of Bisphenol A (BPA), Bisphenol F (BPF) and Bisphenol S (BPS) on PNT1A and PC-3 cells, focusing on their effects on endoplasmic reticulum (ER) stress and related pathways. PNT1A and PC-3 were treated with BPA, BPF and BPS at concentrations of 0.1, 1 and 10 μM for 48 h cytotoxicity, BrdU cell proliferation, ROS generation, apoptosis detection, gene expression analysis and Western blot analysis were performed. BPA induced proliferation and late apoptosis in PNT1A cells, whereas it induced both late apoptosis and early apoptosis in PC-3 cells. BPF and BPS induced late apoptosis in PC-3 cells. Increased ROS levels were observed in PNT1A cells exposed to 1-10 μM BPA. BPA, BPF and BPS increased the expression levels of ER stress-related genes in PNT1A cells. Furthermore, exposure to BPA increased the expression of ER stress-related CHOP/DDIT3 protein in PNT1A cells. These findings highlight the potential health risks associated with BPA, BPF and BPS exposure and emphasize the importance of investigating the underlying mechanisms by which these chemicals may affect human health. Further research is required to comprehensively understand the role of ER stress pathways in cellular responses to these substances.

Combining computational tools and experimental studies towards endocrine disruptors mitigation: A review of biocatalytic and adsorptive processes

The endocrine disruptors (EDCs) are an important group of emerging contaminants, and their mitigation has been a huge challenge due to their chemistry complexity and variety of these compounds. The traditional treatments are inefficient to completely remove EDCs, and adsorptive processes are the major alternative investigated on their removal. Also, the use of EDCs degrading enzymes has been encouraged due to ecofriendly approach of biocatalytic processes. This paper highlights the occurrence, classification, and toxicity of EDCs with special focus in the use of enzyme-based and adsorptive technologies in the elimination of EDCs from ambiental matrices. Numerous prior reviews have focused on the discussions toward these technologies. However, the literature lacks theoretical discussions about important aspects of these methods such as the mechanisms of EDCs adsorption on the adsorbent surface or the interactions between degrading enzymes - EDCs. In this sense, theoretical calculations combined to experimental studies may help in the development of more efficient technologies to EDCs mitigation. In this review, we point out how computational tools such as molecular docking and molecular dynamics have to contribute to the design of new adsorbents and efficient catalytic processes towards endocrine disruptors mitigation.

Association between Urinary BPA Substitutes and Precocious Puberty among Girls: A Single-Exposure and Mixed Exposure Approach from a Chinese Case-Control Study

There is an argument that BPA substitutes may have the same or more deleterious health effects as BPA due to their structural similarity. This study explored the association between urinary BPA substitutes and precocious puberty among girls by including 120 girls with precocious puberty (cases) aged 2-10 years enrolled at Nanjing Children's Hospital Department of Endocrinology in China between April 2021 to September 2021 and 145 healthy girls (controls) recruited from a primary school. Logistic regression was used to evaluate the effect of single exposures, and Bayesian kernel machine regression (BKMR) and quantile-based g-computation were used for the mixed effect. In the multivariate logistic regression, BPS (bisphenol S), TBBPA (tetrabromobisphenol A), and BPFL (bisphenol-FL) were significantly associated with increased risk of precocious puberty (odds ratio (OR) = 1.75, 95% confidence interval (CI): 1.13, 2.76, p = 0.014), (OR = 1.46, CI: 1.06, 2.05; p = 0.023), and (OR = 1.47, CI: 1.01, 2.18; p = 0.047), respectively. The BMKR and quantile-based g-computation models revealed consistent associations for single exposures and there was insufficient evidence for the associations of the mixed exposure of bisphenols with precocious puberty. In conclusion, BPA substitutes such as BPS, TBBPA, and BPFL may be associated with an increased risk of precocious puberty in girls.

Large-scale biomonitoring of bisphenol analogues and their metabolites in human urine from Guangzhou, China: Implications for health risk assessment

Bisphenol analogues (BPs) are ubiquitous in the environment and have gained significant attention regarding their associated health risks. However, there is a lack of comprehensive biomonitoring data on BPs and their metabolites in human urine. To address this, we conducted a study evaluate the exposure to BPs in the general population of Guangzhou, China. A total of 1440 urine samples were collected from volunteers and analyzed for the presence of BPs and their metabolites after being pooled into 36 groups based on age and gender. The findings revealed the common detection of ten free-form BPs, as well as the urinary metabolites of BPA and BPS, in the pooled urine samples. BPA was the predominant free-form compound, constituting 50% of the total BPs. The primary urinary metabolites of BPA and BPS are BPA-G and BPS-G, respectively, indicating glucuronidation as their primary metabolic pathway. The composition of urinary metabolites of BPA and BPS varied by age and sex, while the concentration of total BPs in urine was not significantly associated with age and sex. Enzymatic hydrolysis yielded a mean amplification of individual BPs concentrations in urine samples ranging from 1.8 times (BPA) to 4.6 times (BPS). Based on the outcomes, it was estimated that conjugated forms accounted for 96.9%, 96.2%, 94.7%, 94.1%, 92.6%, 89.1%, 87.3%, 87.2%, 87.1% and 85.8% of BPP, BPAF, BPZ, BPE, BPAP, BPF, BPA, BPC, BPS and BPF, respectively, in the pooled urine samples. Preliminary risk assessments indicated that the estimated daily intake of BPA was much higher than the latest proposed tolerable daily intake. Due to the unavailability of health-based guideline values for alternative BPs, some of them exhibit daily intakes comparable to BPA, implying that greater attention should be paid to health risks associated with exposure to BPs.

Estrogens and endocrine-disrupting chemicals differentially impact the bioenergetic fluxes of mammary epithelial cells in two- and three-dimensional models

Due to its sensitivity to hormonal signaling, the mammary gland is often referred to as a sentinel organ for the study of endocrine-disrupting chemicals (EDCs), environmental pollutants that can interfere with the estrogen signaling pathway and induce mammary developmental defects. If and how EDCs impact mammary epithelial cell metabolism has not yet been documented. Herein, to study how estrogens and EDCs modulate mammary gland metabolism, we performed bioenergetic flux analyses using mouse mammary epithelial organoids compared to cells grown in monolayer culture. Several EDCs were tested, including bisphenol A (BPA), its close derivative BPS, a new BPA replacement copolyester called TritanTM, and the herbicide glyphosate. We report that estrogens reprogrammed mammary epithelial cell metabolism differently when grown in two- and three-dimensional models. Specific EDCs were also demonstrated to alter bioenergetic fluxes, thus identifying a new potential adverse effect of these molecules. Notably, organoids were more sensitive to low EDC concentrations, highlighting them as a key model for screening the impact of various environmental pollutants. Mechanistically, transcriptomic analyses revealed that EDCs interfered with the regulation of estrogen target genes and the expression of metabolic genes in organoids. Furthermore, co-treatment with the anti-estrogen fulvestrant blocked these metabolic impacts of EDCs, suggesting that, at least partially, they act through modulation of the estrogen receptor activity. Finally, we demonstrate that mammary organoids can be used for long-term studies on EDC exposure to study alterations in organogenesis/morphogenesis and that past pregnancies can modulate the sensitivity of mammary epithelial organoids to specific EDCs. Overall, this study demonstrates that estrogens and EDCs modulate mammary epithelial cell metabolism in monolayer and organoid cultures. A better understanding of the metabolic impacts of EDCs will allow a better appreciation of their adverse effects on mammary gland development and function.

Inhalation of polycarbonate emissions generated during 3D printing processes affects neuroendocrine function in male rats

Three-dimensional (3D) printing of manufactured goods has increased in the last 10 years. The increased use of this technology has resulted in questions regarding the influence of inhaling emissions generated during printing. The goal of this study was to determine if inhalation of particulate and/or toxic chemicals generated during printing with polycarbonate (PC) plastic affected the neuroendocrine system. Male rats were exposed to 3D-printer emissions (592 µg particulate/m3 air) or filtered air for 4 h/day (d), 4 days/week and total exposures lengths were 1, 4, 8, 15 or 30 days. The effects of these exposures on hormone concentrations, and markers of function and/or injury in the olfactory bulb, hypothalamus and testes were measured after 1, 8 and 30 days exposure. Thirty days of exposure to 3D printer emissions resulted in reductions in thyroid stimulating hormone, follicle stimulating hormone and prolactin. These changes were accompanied by (1) elevation in markers of cell injury; (2) reductions in active mitochondria in the olfactory bulb, diminished gonadotropin releasing hormone cells and fibers as well as less tyrosine hydroxylase immunolabeled fibers in the arcuate nucleus; and (3) decrease in spermatogonium. Polycarbonate plastics may contain bisphenol A, and the effects of exposure to these 3D printer-generated emissions on neuroendocrine function are similar to those noted following exposure to bisphenol A.

Degradation and toxicity of bisphenol A and S during cold atmospheric pressure plasma treatment

Bisphenols are widely recognised as toxic compounds that potentially threaten the environment and public health. Here we report the use of cold atmospheric pressure plasma (CAP) to remove bisphenol A (BPA) and bisphenol S (BPS) from aqueous systems. Additionally, methanol was added as a radical scavenger to simulate environmental conditions. After 480 s of plasma treatment, 15-25 % of BPA remained, compared to > 80 % of BPS, with BPA being removed faster (-k_t = 3.4 ms^-1, half-life = 210 s) than BPS (-k_t = 0.15 ms^-1, half-life 4700 s). The characterisation of plasma species showed that adding a radical scavenger affects the formation of reactive oxygen and nitrogen species, resulting in a lower amount of ˙OH, H₂O₂, and NO₂^- but a similar amount of NO₃^-. In addition, a non-target approach enabled the elucidation of 11 BPA and five BPS transformation products. From this data, transformation pathways were proposed for both compounds, indicating nitrification with further cleavage, demethylation, and carboxylation, and the coupling of smaller bisphenol intermediates. The toxicological characterisation of the in vitro HepG2 cell model has shown that the mixture of transformation products formed during CAP is less toxic than BPA and BPS, indicating that CAP is effective in safely degrading bisphenols.

Toxicological evaluation of bisphenol analogues: preventive measures and therapeutic interventions

Bisphenol A (BPA) is a prominent endocrine-disrupting compound that shares structural similarities with estrogen. It is widely used, particularly in the production of food packaging, canned goods, and dental sealants. Of the eight bisphenol analogues, BPA is the most frequently utilized chemical in packaging food items, canned foods and dental sealants. However, chronic exposure to BPA can pose severe health risks, particularly in children. To ensure public safety, it is crucial to adopt proper precautionary measures to minimize BPA exposure. This article explores the toxic effects of bisphenols on various body systems and mechanisms, shedding light on their impact on the reproductive and endocrine system, obesity, albuminuria, and the generation of reactive oxygen species. Understanding the detrimental effects of bisphenols on these systems and mechanisms is vital for developing strategies to mitigate their harmful consequences. Furthermore, the article delves into the biotransformation processes of bisphenols, focusing on their occurrence in vertebrates, invertebrates, plants, and microorganisms. Investigating the biotransformation pathways provides valuable insights into the fate of bisphenols in various organisms and ecosystems. Lastly, the article emphasizes preventive measures to avoid bisphenol exposure and highlights the potential use of plant-based bioactive compounds for treatment strategies. By implementing effective preventive measures, such as utilizing BPA-free products and adopting safer alternatives, individuals can reduce their exposure to bisphenols. Additionally, exploring the potential of plant-based bioactive compounds as therapeutic agents offers promising avenues for addressing the adverse effects of bisphenols. The findings presented herein contribute to a better understanding of the novelty, significance, and potential implications of bisphenol research in the field, aiding in the development of safer practices and interventions to safeguard public health.

Reproductive toxicity of combined effects of endocrine disruptors on human reproduction

Confluence of environmental, genetic, and lifestyle variables is responsible for deterioration of human fecundity. Endocrine disruptors or endocrine disrupting chemicals (EDCs) may be found in a variety of foods, water, air, beverages, and tobacco smoke. It has been demonstrated in experimental investigations that a wide range of endocrine disrupting chemicals have negative effects on human reproductive function. However, evidence on the reproductive consequences of human exposure to endocrine disrupting chemicals is sparse and/or conflicting in the scientific literature. The combined toxicological assessment is a practical method for assessing the hazards of cocktails of chemicals, co-existing in the environment. The current review provides a comprehensive overview of studies emphasizing the combined toxicity of endocrine disrupting chemicals on human reproduction. Endocrine disrupting chemicals interact with each other to disrupt the different endocrine axes, resulting in severe gonadal dysfunctions. Transgenerational epigenetic effects have also been induced in germ cells, mostly through DNA methylation and epimutations. Similarly, after acute or chronic exposure to endocrine disrupting chemicals combinations, increased oxidative stress (OS), elevated antioxidant enzymatic activity, disrupted reproductive cycle, and reduced steroidogenesis are often reported consequences. The article also discusses the concentration addition (CA) and independent action (IA) prediction models, which reveal the importance of various synergistic actions of endocrine disrupting chemicals mixtures. More crucially, this evidence-based study addresses the research limitations and information gaps, as well as particularly presents the future research views on combined endocrine disrupting chemicals toxicity on human reproduction.

Effects of developmental exposures to Bisphenol-A and Bisphenol-S on hepatocellular function in male Long-Evans rats

Bisphenol-S (BPS) is a current substitute for Bisphenol-A (BPA) in various commercial products (paper, plastics, protective can-coatings, etc.) used by all age groups globally. The current literature indicates that a drastic surge in pro-oxidants, pro-apoptotic, and pro-inflammatory biomarkers in combination with diminished mitochondrial activity can potentially decrease hepatic function leading to morbidity and mortality. Consequently, there are increasing public health concerns that substantial Bisphenol-mediated effects may impact hepatocellular functions, particularly in newborns exposed to BPA and BPS postnatally. However, the acute postnatal impact of BPA and BPS and the molecular mechanisms affecting hepatocellular functions are unknown. Therefore, the current study investigated the acute postnatal effect of BPA and BPS on the biomarkers of hepatocellular functions, including oxidative stress, inflammation, apoptosis, and mitochondrial activity in male Long-Evans rats. BPA and BPS (5 and 20 microgram/Liter (μg/L) of drinking water) were administered to 21-day-old male rats for 14 days. BPS had no significant effect on apoptosis, inflammation, and mitochondrial function but significantly reduced the reactive oxygen species (51-60 %, **p < 0.01) and nitrite content (36 %, *p < 0.05), exhibiting hepatoprotective effects. As expected, based on the current scientific literature, BPA induced significant hepatoxicity, as seen by significant glutathione depletion (50 %, *p < 0.05). The in-silico analysis indicated that BPS is effectively absorbed in the gastrointestinal tract without crossing the blood-brain barrier (whereas BPA crosses the blood-brain barrier) and is not a substrate of p-Glycoprotein and Cytochrome P450 enzymes. Thus, the current in-silico and in vivo findings revealed that acute postnatal exposure to BPS had no significant hepatotoxicity.

Effects of perinatal exposure to bisphenol A or S in EAE model of multiple sclerosis

Epidemiological studies support the idea that multiple sclerosis (MS) is a multifactorial disease, overlapping genetic, epigenetic, and environmental factors. A better definition of environmental risks is critical to understand both etiology and the sex-related differences of MS. Exposure to endocrine-disrupting compounds (EDCs) fully represents one of these risks. EDCs are natural or synthetic exogenous substances (or mixtures) that alter the functions of the endocrine system. Among synthetic EDCs, exposure to bisphenol A (BPA) has been implicated in the etiology of MS, but to date, controversial data has emerged. Furthermore, nothing is known about bisphenol S (BPS), one of the most widely used substitutes for BPA. As exposure to bisphenols will not disappear soon, it is necessary to clarify their role also in this pathological condition defining their role in disease onset and course in both sexes. In this study, we examined, in both sexes, the effects of perinatal exposure to BPA and BPS in one of the most widely used mouse models of MS, experimental autoimmune encephalomyelitis (EAE). Exposure to bisphenols seemed to be particularly deleterious in males. In fact, both BPA- and BPS-treated males showed anticipation of the disease onset and an increased motoneuron loss in the spinal cord. Overall, BPA-treated males also displayed an exacerbation of EAE course and an increase in inflammation markers in the spinal cord. Analyzing the consequences of bisphenol exposure on EAE will help to better understand the role of both xenoestrogens and endogenous estrogens on the sexually dimorphic characteristics of MS.

The State of Research and Weight of Evidence on the Epigenetic Effects of Bisphenol A

Bisphenol A (BPA) is a high-production-volume chemical with numerous industrial and consumer applications. BPA is extensively used in the manufacture of polycarbonate plastics and epoxy resins. The widespread utilities of BPA include its use as internal coating for food and beverage cans, bottles, and food-packaging materials, and as a building block for countless goods of common use. BPA can be released into the environment and enter the human body at any stage during its production, or in the process of manufacture, use, or disposal of materials made from this chemical. While the general population is predominantly exposed to BPA through contaminated food and drinking water, non-dietary exposures through the respiratory system, integumentary system, and vertical transmission, as well as other routes of exposure, also exist. BPA is often classified as an endocrine-disrupting chemical as it can act as a xenoestrogen. Exposure to BPA has been associated with developmental, reproductive, cardiovascular, neurological, metabolic, or immune effects, as well as oncogenic effects. BPA can disrupt the synthesis or clearance of hormones by binding and interfering with biological receptors. BPA can also interact with key transcription factors to modulate regulation of gene expression. Over the past 17 years, an epigenetic mechanism of action for BPA has emerged. This article summarizes the current state of research on the epigenetic effects of BPA by analyzing the findings from various studies in model systems and human populations. It evaluates the weight of evidence on the ability of BPA to alter the epigenome, while also discussing the direction of future research.

The fate of bisphenol A, bisphenol S, and their respective glucuronide metabolites in ovarian cells

Ovarian cells are critical for reproduction and steroidogenesis, which are functions that can be impacted by exposure to xenobiotics. As in other extra-hepatic tissues, biotransformation events may occur at the ovarian level. Such metabolic events deserve interest, notably as they may modulate the overall exposure and toxicity of xenobiotics. In this study, the comparative metabolic fate of two bisphenols was investigated in ovarian cells. Bisphenol A (BPA), a model endocrine disruptor, and its major substitute bisphenol S (BPS) were selected. Bovine granulosa cells (primary cultures) and theca explants (ex vivo tissue) were exposed for 24hr to tritium-labeled BPA, BPS and their respective glucuronides (i.e. their major circulating forms), at concentrations consistent with low-dose exposure scenarios. Mass balance studies were performed, followed by radio-HPLC profiling. The capability of both cell compartments to biotransform BPA and BPS into their respective sulfo-conjugates was demonstrated, with sulfation being the predominant metabolic route. In theca, there was a significantly higher persistence of BPA (compared to BPS) residues over 24hr. Moreover, only theca explants were able to deconjugate inactive BPA-glucuronide and BPS-glucuronide back into their biologically active aglycone forms. Deconjugation rates were demonstrated to be higher for BPS-G than for BPA-G. These findings raise concerns about the in situ direct release of bisphenols at the level of the ovary and demonstrate the relevance of exploring the biotransformation of bisphenols and their circulating metabolites in different ovarian cells with specific metabolic capabilities. This work also provides essential knowledge for the improved risk assessment of bisphenols.

An Insight into the Metabolism of 2,5-Disubstituted Monotetrazole Bearing Bisphenol Structures: Emerging Bisphenol A Structural Congeners

The non-estrogenic 2,5-disubstituted tetrazole core-bearing bisphenol structures (TbB) are being researched as emerging structural congeners of Bisphenol A, an established industrial endocrine disruptor. However, there is no understanding of TbB's adverse effects elicited via metabolic activation. Therefore, the current study aimed to investigate the metabolism of TbB ligands, with in silico results serving as a guide for in vitro studies. The Cytochrome P450 enzymes (CYP) inhibitory assay of TbB ligands on the seven human liver CYP isoforms (i.e., 1A2, 2A6, 2D6, 2C9, 2C8, 2C19, and 3A4) using human liver microsomes (HLM) revealed TbB ligand 223-3 to have a 50% inhibitory effect on all the CYP isoforms at a 10 μM concentration, except 1A2. The TbB ligand 223-10 inhibited 2B6 and 2C8, whereas the TbB ligand 223-2 inhibited only 2C9. The first-order inactivity rate constant (Kobs) studies indicated TbB ligands 223-3, 223-10 to be time-dependent (TD) inhibitors, whereas the TbB 223-2 ligand did not show such a significant effect. The 223-3 exhibited a TD inhibition for 2C9, 2C19, and 1A2 with Kobs values of 0.0748, 0.0306, and 0.0333 min-1, respectively. On the other hand, the TbB ligand 223-10 inhibited 2C9 in a TD inhibition manner with Kobs value 0.0748 min-1. However, the TbB ligand 223-2 showed no significant TD inhibition effect on the CYPs. The 223-2 ligand biotransformation pathway by in vitro studies in cryopreserved human hepatocytes suggested the clearance via glucuronidation with the predominant detection of only 223-2 derived mono glucuronide as a potential inactive metabolite. The present study demonstrated that the 223-2 ligand did not elicit any significant adverse effect via metabolic activation, thus paving the way for its in vivo drug-drug interactions (DDI) studies.

Bisphenol A (BPA) induces apoptosis of mouse Leydig cells via oxidative stress

As one of the most frequently produced synthetic compounds worldwide, bisphenol A (BPA) has been widely used in many kinds of products such as appliances, housewares, and beverage cans. BPA has been shown to cause damage to male reproductive system; however, the potential mechanism remains to be investigated. In the present study, BPA exposure decreased the testis and epididymis coefficient, caused a disintegration of germinal epithelium, decreased the density and motility of sperm in the epididymis tissue, and increased the number of abnormal sperm morphology, which indicated that BPA exposure could cause damage to testis. BPA was also shown to induce apoptosis and oxidative stress in the testis tissue. The serum testosterone concentration was decreased in the BPA-treated group, suggesting that BPA could lead to Leydig cell damage. Subsequently, mouse TM3 cell, a kind of mouse Leydig cell line, was utilized to investigate the potential mechanism. Herein, we showed that BPA exposure could inhibit cell viability and induce apoptosis of TM3 cells. Furthermore, oxidative stress in the cells could also be induced by BPA, while the inhibition of oxidative stress by N-acetyl-L-cysteine (NAC), an oxidative stress scavenger, could reverse the inhibition of cell viability and induction of apoptosis by BPA exposure, indicating that oxidative stress was involved in BPA-induced apoptosis of TM3 cells. Finally, RNA-sequencing and real-time PCR were utilized to screen and validate the potential oxidative stress-related genes involving in BPA-induced apoptosis. We found that BPA exposure increased the mRNA levels of oxidative stress-related genes such as Lonp1, Klf4, Rack1, Egln1, Txn2, Msrb1, Atox1, Mtr, and Atp2a2, as well as decreased the mRNA level of Dhfr gene; while NAC could rescue the expression of these genes. Taken together, oxidative stress was involved in BPA-induced apoptosis of mouse Leydig cells.

Aerobic degradation of bisphenol A by Pseudomonas sp. LM-1: characteristic and pathway

Bisphenol A (BPA) has been widely used in the manufacture of polymeric materials. BPA is regarded as an endocrine disrupting chemical, posing a great threat to the public health. In this study, a bacterial strain LM-1, capable of utilizing BPA as the sole carbon and energy source under aerobic conditions, was originally isolated from an activated sludge sample. The isolate was identified as Pseudomonas sp. based on 16S rRNA gene sequence analysis. Strain LM-1 was able to completely degrade 25-100 mg/L BPA within 14-24 h, and it also exhibited high capacity for BPA degradation at a range of pH (6.0-8.0). (NH₄)₂SO₄ and NH₄NO₃ were the suitable nitrogen sources for its growth and BPA biodegradation, and the BPA degradation could be accelerated when exogenous carbon sources were introduced as the co-substrates. Metal ions such as Zn²⁺, Cu²⁺, and Ni²⁺ could considerably suppress the growth of strain LM-1 and BPA degradation. According to the analysis of liquid chromatography coupled to Q-Exactive high resolution mass spectrometry, hydroquinone, p-hydroxybenzaldehyde, and p-hydroxybenzoate were the predominate metabolites in the BPA biodegradation and the degradation pathways were proposed. This study is important for assessment of the fate of BPA in engineered and natural systems and possibly for designing bioremediation strategies.

Effects of the long-term influence of bisphenol A and bisphenol S on the population of nitrergic neurons in the enteric nervous system of the mouse stomach

Bisphenol A (BPA) is an endocrine disruptor commonly used in the production of plastics. Due to its relatively well-known harmful effects on living organisms, BPA is often replaced by its various analogues. One of them is bisphenol S (BPS), widely used in the plastics industry. Until recently, BPS was considered completely safe, but currently, it is known that it is not safe for various internal organs. However, knowledge about the influence of BPS on the nervous system is scarce. Therefore, the aim of this study was to investigate the influence of two doses of BPA and BPS on the enteric nitrergic neurons in the CD1 strain mouse stomach using the double-immunofluorescence technique. The study found that both substances studied increased the number of nitrergic neurons, although changes under the impact of BPS were less visible than those induced by BPA. Therefore, the obtained results, for the first time, clearly indicate that BPS is not safe for the innervation of the gastrointestinal tract.

Human body burden of bisphenol A: a case study of lactating mothers in Florianopolis, Brazil

Exclusive breast milk is the diet recommended by the World Health Organization (WHO) until 6 months of age. However, breastfeeding has the potential of transferring certain toxic chemicals from the mother to the infant. Bisphenol A (BPA) is a synthetic chemical used as a monomer in polycarbonate plastics and epoxy resins. Information on BPA concentration in the breast milk of lactating mothers is very limited; thus, this study aimed to determine the concentration of BPA in the colostrum of 64 post-partum women at a university-affiliated tertiary hospital in South Brazil. The results showed that all the breast milk samples contained a high concentration of BPA with a median value of 34.18 ng/mL. Furthermore, the concentration of BPA in mothers was influenced by the consumption of foods packaged in plastic packaging, especially when the plastic is heated (p = 0.0182). The total daily intake of BPA in breastfed infants was 19.5 µg/kg/day and 28.5 µg/kg/day was recorded at the 95th percentile of body weight per day, which is higher than the maximum daily intake estimated by the European Authority of Food Safety. These data showed a high concentration of BPA in the breastmilk of the lactating mothers which might be through the use of plastic containers as food/drink packages. This is of public health importance as the high concentration of BPA in their breast milk can be an indicator of potentially serious health problems in these mothers and much more in the babies breastfed with BPA-contaminated breast milk.

Adverse (geno)toxic effects of bisphenol A and its analogues in hepatic 3D cell model

Bisphenol A (BPA) is one of the most widely used and versatile chemical compounds in polymer additives and epoxy resins for manufacturing a range of products for human applications. It is known as endocrine disruptor, however, there is growing evidence that it is genotoxic. Because of its adverse effects, the European Union has restricted its use to protect human health and the environment. As a result, the industry has begun developing BPA analogues, but there are not yet sufficient toxicity data to claim that they are safe. We investigated the adverse toxic effects of BPA and its analogues (BPS, BPAP, BPAF, BPFL, and BPC) with emphasis on their cytotoxic and genotoxic activities after short (24-h) and prolonged (96-h) exposure in in vitro hepatic three-dimensional cell model developed from HepG2 cells. The results showed that BPFL and BPC (formed by an additional ring system) were the most cytotoxic analogues that affected cell viability, spheroid surface area and morphology, cell proliferation, and apoptotic cell death. BPA, BPAP, and BPAF induced DNA double-strand break formation (γH2AX assay), whereas BPAF and BPC increased the percentage of p-H3-positive cells, indicating their aneugenic activity. All BPs induced DNA single-strand break formation (comet assay), with BPAP (≥0.1 μM) being the most effective and BPA and BPC the least effective (≥1 μM) under conditions applied. The results indicate that not all of the analogues studied are safer alternatives to BPA and thus more in-depth research is urgently needed to adequately evaluate the risks of BPA analogues and assess their safety for humans.

Comparison of toxicokinetic properties of eleven analogues of Bisphenol A in pig after intravenous and oral administrations

Due to the restrictions of its use, Bisphenol A (BPA) has been replaced by many structurally related bisphenols (BPs) in consumer products. The endocrine disrupting potential similar to that of BPA has been described for several bisphenols, there is therefore an urgent need of toxicokinetic (TK) data for these emerging BPs in order to evaluate if their internal exposure could increase the risk of endocrine disruption. We investigated TK behaviors of eleven BPA substitutes (BPS, BPAF, BPB, BPF, BPM, BPZ, 3-3BPA, BP4-4, BPAP, BPP, and BPFL) by intravenous and oral administrations of mixtures of them to piglets and serial collection of blood over 72 h and urine over 24 h, to evaluate their disposition. Data were analyzed using nonlinear mixed-effects modeling and a comparison was made with TK predicted by the generic model HTTK package. The low urinary excretion of some BPs, in particular BPM, BPP and BPFL, is an important aspect to consider in predicting human exposure based on urine biomonitoring. Despite their structural similarities, for the same oral dose, all BPA analogues investigated showed a higher systemic exposure (area under the plasma concentration-time curve (AUC) of the unconjugated Bisphenol) than BPA (2 to 4 fold for 3-3BPA, BPAF, BPB and BPZ, 7-20 fold for BP4-4, BPAP, BPP, BPFL, BPF and BPM and 150 fold for BPS) due mainly to a considerable variation of oral bioavailability (proportion of BP administered by oral route that attains the systemic circulation unchanged). Given similarities in the digestive tract between pigs and humans, our TK data suggest that replacing BPA with some of its alternatives, particularly BPS, will likely lead to higher internal exposure to potential endocrine disruptive compounds. These findings are crucial for evaluating the risk of human exposure to these emerging BPs.

A new identity of microcystins: Environmental endocrine disruptors? An evidence-based review

Microcystins (MCs) are widely distributed cyanobacterial toxins in eutrophic waters. At present, the endocrine-disrupting effects of MCs have been extensively studied, but whether MCs can be classified as environmental endocrine disruptors (EDCs) is still unclear. This review is aimed to evaluate the rationality for MCs as to be classified as EDCs based on the available evidence. It has been identified that MCs meet eight of ten key characteristics of chemicals that can be classified as EDCs. MCs interfere with the six processes, including synthesis, release, circulation, metabolism, binding and action of natural hormones in the body. Also, they are fit two other characteristics of EDC: altering the fate of producing/responding cells and epigenetic modification. Further evidence indicates that the endocrine-disrupting effect of MCs may be an important cause of adverse health outcomes such as metabolic disorders, reproductive disorders and effects on the growth and development of offspring. Generally, MCs have endocrine-disrupting properties, suggesting that it is reasonable for them to be considered EDCs. This is of great importance in understanding and evaluating the harm done by MCs on humans.

Bisphenol S induced dysregulations in liver; iron regulatory genes and inflammatory mediators in male Wistar rats

Bisphenol S (BPS), an analog of bisphenol A (BPA), has been frequently detected in consumer products, food wrappers, plastics, and thermal papers. Since the liver is a hub of metabolic and detoxification pathways, thus intimately related to BPS presence in the environment and body. The current study was designed to investigate the effects of BPS administration in an animal model. Twenty-five male Wistar rats weighing 175 ± 25 g were randomly divided into control and treated groups. The control group was further divided into group I (no treatment) and group II (corn oil), whereas the treatment group was divided into D-I (40 mg/kg/day), D-II (200 mg/kg/day), and D-III (400 mg/kg/day) groups, getting oral doses of BPS for 15 days. Data analysis showed a significant statistical increase in hepatic enzymes ALT (33.4%), AST (25.4%), and ALP (529.6%) in the D-III group along with the development of hypercholesterolemia and hypertriglyceridemia in all BPS groups. Aberrant mRNA expressions of some key hepatic iron regulatory genes and inflammatory mediators were evident through qRT-PCR. Bisphenol S caused congestion of central vein from mild to moderate in hepatic sections. In conclusion, our investigation insinuates BPS intoxication potential and therefore may not be a safe alternative to BPA.

Applicability of an on-line solid-phase extraction liquid chromatography - tandem mass spectrometry for the wastewater-based assessment of human exposure to chemicals from personal care and household products

Wastewater-based epidemiology (WBE) can be a useful complementary approach to assess human exposure to potentially harmful chemicals, including those from personal care and household products. In this work, a fully automated multiresidue method, based on on-line solid-phase extraction liquid chromatography - tandem mass spectrometry, was developed for the determination of 27 biomarkers of human exposure to selected chemicals from personal care and household products, including parabens, UV filters, phthalates and alternative plasticizers, phosphorous flame retardants/plasticizers (PFRs), and bisphenols. These biomarkers include both the parent compounds and their human metabolites. In addition, two oxidative stress biomarkers, 8-epi-prostaglandin F2α and 4-hydroxy nonenal mercapturic acid, were also considered in the study. The method was carefully optimized to tackle the challenges of analyzing compounds with different physico-chemical properties in a highly complex raw wastewater matrix, while model experiments were performed to investigate filtration losses and analyte stability. The applicability of the developed method was tested by analyzing raw wastewater from four European cities: Antwerp, Brussels (Belgium), Girona (Spain), and Zagreb (Croatia). Twenty-one biomarkers (10 parent compounds and 11 metabolites) were detected in all analyzed wastewater samples. The parent compounds with the highest mass loads were PFRs, parabens, and bisphenol S, while phthalate monoesters were the most prominent metabolites. The mass loads of most compounds were quite similar across cities, but geographic differences were observed for some biomarkers, such as metabolites of phthalates and alternative plasticizers. Exposure was then assessed for seven substances for which quantitative urinary excretion data are known. Our results indicate that safe reference values were exceeded for several contaminants, including butylated phthalates, bisphenol A, and tris(2-butoxyethyl) phosphate, particularly for toddlers. With this relatively simple method, which requires less sample manipulation, it is possible to promptly identify and monitor exposure to harmful chemicals at the population level using the WBE approach.

Association between Ultra-Processed Food Consumption and Diabetes in Chinese Adults-Results from the China Health and Nutrition Survey

Aims: We aimed to assess the association between ultra-processed food (UPF) consumption with diabetes in Chinese adults. Methods: This study included 12,849 eligible adults aged 20 years and over attending at least two surveys in the China Nutrition and Health Survey during 1997−2011. Food intake at each survey was assessed by a 3-day 24-h dietary recall method. UPF was defined based on the NOVA classification. Diabetes was obtained from questionnaires and/or ascertained by fasting blood tests. The association of diabetes with UPF was examined using mix effect logistic regression adjusting for potential confounding factors. Results: The mean age of the participants was 43.3 (SD 14.8) years. The age and gender adjusted mean UPF intake increased four times and the prevalence of diabetes increased eight times in 1997−2011. Compared with non-consumers, the odds ratios (95% CI) of diabetes for those with mean UPF consumption of 1−19 g/day, 20−49 g/day, and ≥50 g/day were 1.21 (0.98, 1.48), 1.49 (1.19, 1.86), and 1.40 (1.08, 1.80), respectively (p trend < 0.001) after adjusted for the measured covariates including lifestyle factors (smoking, alcohol drinking, and physical activity), BMI and hypertension. Conclusions: both UPF consumption and prevalence of diabetes increased among adults in China during 1997−2011. Higher UPF consumption was positively associated with diabetes.

55 xenobiotic organic compounds in Tripoli landfill-Lebanon leachate and their fluxes to the Abou Ali River and Mediterranean Sea

Pollution generated from landfill solid wastes constitute one of the major threat to the environment. The landfill leachate contains various toxic pollutants, making it the most dangerous issue of the landfills. Monitoring the xenobiotic organic concentrations in landfill leachate is an important step to evaluate the environmental impacts. This work aims to characterize the seasonal variation of 55 xenobiotic organic compounds including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), phthalic acid esters (PAEs) and bisphenols (BPs) in the leachate from municipal solid waste landfill of Tripoli, Lebanon. And also, the quantity of the pollutant's flux to the Abou Ali River and the Mediterranean Sea nearby has been estimated. The organic pollutants were extracted by using the solid-phase extraction and quantified by using GC-MS/MS. The results showed high level of PAEs, BPs, PCBs, and PAHs in the leachate samples. The fluxes of pollutants to the Abou Ali River and Mediterranean Sea have been detected at 0.23 kg, 0.01 kg, 116.85 kg, 15.93 kg, and 7.58 kg for Σ₁₆PAHs, Σ₂₈PCBs, Σ₆PAEs, Σ₄BPs, and 4-NP respectively.

Human health risk assessment of bisphenol A (BPA) through meat products

Meat and meat products are often consumed in our daily diet, providing essential nutrients. Contamination by chemical hazards, including bisphenol A (BPA) in meat products, is a concern and is continuously monitored. BPA is well-known for its endocrine-disrupting properties, which may cause potential toxicological effects on reproductive, nervous, and immune systems. Dietary consumption is the main route of BPA exposure, and meat products are a major contributor. BPA exposure from meat consumption is the focus of this review. This review found that BPA has been widely detected in canned and non-canned meat products. BPA in canned meat is assumed to be predominantly from migration from can coatings. Relatively low levels are observed in non-canned products, and the source of contamination in these products has yet to be definitively identified. A recent European Food Safety Authority (EFSA) draft opinion has proposed to lower the tolerable daily intake of BPA from 4 μg kg body weight (bw)^-1 day^-1 to 0.04 ng kg body weight (bw)^-1 day^-1, therefore potential health risks need to be addressed. This review has investigated potential contamination at the farm, industrial processes, and retail levels. Data gaps in the literature are also identified to improve future food safety in the meat industry. Also, a unified risk assessment strategy has been proposed. Further understanding of BPA migration in meat products is needed as a part of the exposure assessment to reduce potential risk, and more data on the dose-response relationship will help comprehend potential adverse health effects of BPA on humans. This research will inform the public, meat producers and processing industry, and policymakers on potential exposure to BPA and risk reduction measures, thus, ensuring food safety.

Exposure to phthalates, phenols, and parabens mixture and alterations in sex steroid hormones among adolescents

Exposure to phthalates (PAEs), phenols, and parabens has been linked with sex hormone imbalance; however, previous studies were predominantly limited to adults and failed to examine the combined effects of these chemicals mixture among adolescents. Thus, we used the data from the National Health and Nutrition Examination Survey (2013-2016) to explore the associations of urinary PAEs, phenols, and parabens biomarkers with sex hormones among participants aged 12-19 years old (n = 613). Latent class analysis (LCA) and quantile-based g-computation (QGC) were applied to assess the associations of the latent exposure profiles and chemicals mixture with sex hormone indicators, including steroid hormones and sex hormone binding globulin (SHBG), in adolescents and by sex. Using LCA, four latent classes were identified among all participants. Compared with the class characterized by "Low exposure", the class represented by "High PAEs" [mono (2-ethyl-5-carboxypentyl) phthalate (MECPP), mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and monobenzyl phthalate (MBZP)] had lower level of estradiol (E₂) [β = -0.249, 95% confidence interval (CI): -0.419, -0.08], free androgen index (FAI) (β = -0.258, 95%CI: -0.512, -0.005) and free testosterone (FT) (β = -0.248, 95%CI: -0.496, -0.001) among male adolescents. These results were echoed by the results in QGC analyses, where PAEs mixture was negatively associated with E₂ (β = -0.137, 95% CI: -0.263, -0.011), FAI (β = -0.198, 95%CI: -0.387, -0.008) and FT (β = -0.189, 95%CI: -0.375, -0.002) among male adolescents. By contrast, the associations of the identified latent classes or chemicals mixture with sex hormone indicators were generally nonsignificant among female counterparts, except for a positive association between PAEs mixture and SHBG (β = 0.121, 95%CI: 0.012, 0.23). Our study demonstrated that exposure to PAEs, particularly MECPP, MEHHP, and MBZP, would be a threat to the sex hormone homeostasis of male adolescents.

Last piece in the puzzle of bisphenols BPA, BPS and BPF metabolism: Kinetics of the in vitro sulfation reaction

Bisphenols are endocrine-disrupting chemicals ubiquitously present in the environment, with the consequent exposure to humans. In humans, bisphenols are metabolized to glucuronide and sulfate conjugates. Recent studies indicate that sulfation represents an important bisphenol metabolic pathway for the most vulnerable humans, such as the growing fetus. Our aim was to evaluate sulfation kinetics of commonly detected bisphenols in biological samples: bisphenol A (BPA), bisphenol S (BPS), and bisphenol F (BPF). Furthermore, we evaluated estrogenic agonist potencies and long-term stability of these bisphenol sulfates. BPS and BPF sulfates were prepared by chemical synthesis. Sulfation kinetics of the selected bisphenols were tested in pooled human liver cytosol, as a source for soluble phase II enzymes, including liver sulfotransferases, with quantification by LC-MS/MS. A validated transactivation assay using the hERα-Hela 9903 cell line was used to determine estrogenic agonist potencies. Moreover, BPA, BPS, and BPF sulfate stabilities were examined under various conditions and during storage. In vitro sulfation of BPA and BPS followed Michaelis-Menten kinetics; BPF sulfation followed a substrate inhibition model. Sulfation rates were comparable for these bisphenols, although their K_M values indicated some large differences in affinities. BPA and BPS sulfates are not hERα agonists. The bisphenol sulfates can be considered stable for at least 2 days under these tested media conditions. These data indicate that bisphenol sulfation is an important route in their biotransformation. Compared to glucuronidation, these bisphenols show slower sulfation rates but similar K_M values. BPA and BPS metabolic biotransformation by sulfation provides their detoxification as they are without estrogenic activities.

Covalent Protein Modification: An Unignorable Factor for Bisphenol A-Induced Hepatotoxicity

Covalent modification of proteins by reactive pollutants/metabolites might trigger various toxicities resulting from the disruption of protein structures and/or functions, which is critical for understanding the mechanism of pollutants-induced toxicity. However, this mechanism has rarely been touched on due to the lack of a methodology. In this research, the protein modification of bisphenol A (BPA) in rats was characterized using a series of liquid chromatography-tandem mass spectrometry (LC-MS) approaches. BPA-modified cysteine (Cys1) was first released from proteins via enzymatic hydrolysis and identified using LC-MS. Moreover, the positive correlation between Cys1 and hepatotoxicity indicated the involvement of protein modification in BPA toxicity. Then, in vitro incubation of BPA with amino acids and protein confirmed that BPA could specifically modify cysteine residues of proteins after bioactivation and provided four additional modification patterns. Finally, 24 BPA-modified proteins were identified from the liver of BPA-exposed rats using proteomic analysis, and they were mainly enriched in oxidative stress-related pathways. The modification on superoxide dismutases, catalase, and glutathione S-transferases disrupted their enzymatic functions, leading to oxidative damage. These results revealed that the covalent protein modification is an unignorable factor for BPA hepatotoxicity. Moreover, the workflow can be applied to identify protein adducts of other emerging contaminants and possible risk.

Effects of BPA substitutes on the prenatal and cardiovascular systems

Bisphenol A (BPA) is a ubiquitous chemical compound constantly being released into the environment, making it one of the most persistent endocrine-disrupting chemical (EDC) in nature. This EDC has already been associated with developing various pathologies, such as diabetes, obesity, and cardiovascular, renal, and behavioral complications, among others. Therefore, over the years, BPA has been replaced, gradually, by its analog compounds. However, these compounds are structurally similar to BPA, so, in recent years, questions have been raised concerning their safety for human health. Numerous investigations have been performed to determine the effects BPA substitutes may cause, particularly during pregnancy and prenatal life. On the other hand, studies investigating the association of these compounds with the development of cardiovascular diseases (CVD) have been developed. In this sense, this review summarizes the existing literature on the transgenerational transfer of BPA substitutes and the consequent effects on maternal and offspring health following prenatal exposure. In addition, these compounds' effects on the cardiovascular system and the susceptibility to develop CVD will be presented. Therefore, this review aims to highlight the need to investigate further the safety and benefits, or hazards, associated with replacing BPA with its analogs.

The toxicokinetics of bisphenol A and its metabolites in fish elucidated by a PBTK model

Bisphenol A (BPA) is a chemical of major concern due to its endocrine disrupting function, high production volume, and persistence in the aquatic environment. Consequently, organisms such as fish are subject to chronic exposure to BPA. However, physiologically-based toxicokinetic (PBTK) models, which are valuable tools to improve the understanding of a chemical's fate in an organism, have never been specifically adapted to model BPA toxicokinetics (TK) in fish. In our work, an existing PBTK developed for four different fish species was modified to model BPA ADME processes (absorption, distribution, metabolization and excretion). The metabolization of BPA into BPA-monoglucuronide (BPA gluc) and BPA-monosulfate (BPA sulf) and their TK in various organs was taking into account in the model. Experiments were performed to generate BPA TK data in a model species commonly used in ecotoxicology, the stickleback. The model structure had to include two sites of metabolization to simulate BPA TK accurately in stickleback organs. Thus, the fish liver may not be the only site of the metabolization of BPA: plasma or gills could also play a role in BPA metabolization. The PBTK model predictive performance evaluated on literature data in zebrafish and rainbow trout concurs with this conclusion. Finally, a calibration mixing data from the three species was compared to the calibration on stickleback data only.

The bisphenol A metabolite MBP causes proteome alterations in male Cyprinodon variegatus fish characteristic of estrogenic endocrine disruption

The toxicological status of bisphenol A (BPA) is under strong debate. Whereas in vitro it is an agonist of the estrogen receptor with a potency ca. 10⁵-fold lower than the natural female hormone estradiol, in vivo exposure causes only mild effects at concentration thresholds environmentally not relevant and inconsistent among species. By using a proteomic approach, shotgun liver proteome analysis, we show that 7-d exposure to 10 μg/L of the BPA metabolite, 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP), and not the same exposure to the parental molecule BPA, alters the liver proteome of male Cyprinodon variegatus fish. Different physiological and environmental conditions leading to biotransformation of BPA to MBP may partly explain the conflicting results so far reported for in vivo BPA exposures. The pattern of alteration induced by MBP is similar to that caused by estradiol, and indicative of estrogenic endocrine disruption. MBP enhanced ribosomal activity, protein synthesis and transport, with upregulation of 91% of the ribosome-related proteins, and 12 proteins whose expression is regulated by estrogen-responsive elements, including vitellogenin and zona pellucida. Whey acidic protein (WAP) was the protein most affected by MBP exposure (FC = 68). This result points at WAP as novel biomarker for xenoestrogens.

Human Biomonitoring Guidance Values (HBM-GVs) for Bisphenol S and Assessment of the Risk Due to the Exposure to Bisphenols A and S, in Europe

Within the European Joint Programme HBM4EU, Human Biomonitoring Guidance Values (HBM-GVs) were derived for several prioritised substances. In this paper, the derivation of HBM-GVs for the general population (HBM-GVGenPop) and workers (HBM-GVworker) referring to bisphenol S (BPS) is presented. For the general population, this resulted in an estimation of the total urinary concentration of BPS of 1.0 µg/L assuming a 24 h continuous exposure to BPS. For workers, the modelling was refined in order to reflect continuous exposure during the working day, leading to a total urinary concentration of BPS of 3.0 µg/L. The usefulness for risk assessment of the HBM-GVs derived for BPS and bisphenol A (BPA) is illustrated. Risk Characterisation Ratios (RCRs) were calculated leading to a clear difference between risk assessments performed for both bisphenols, with a very low RCR regarding exposure to BPA., contrary to that obtained for BPS. This may be due to the endocrine mediated endpoints selected to derive the HBM-GVs for BPS, whereas the values calculated for BPA are based on the temporary Tolerable Daily Intake (t-TDI) from EFSA set in 2015. A comparison with the revised TDI recently opened for comments by EFSA is also discussed. Regarding the occupational field, results indicate that the risk from occupational exposure to both bisphenols cannot be disregarded.

Computational risk assessment framework for the hazard analysis of bisphenols and quinone metabolites

Bisphenol A (BPA) is a widely used chemical in plastics but its proven harmful effects has led to the replacement and production of its analogs that might also induce hazard as well as associated risks. To elucidate the adverse impact of the BPA analogs, a comprehensive computational framework is developed which applies toxicogenomics aligned with Density Functional Theory (DFT) and Molecular Dynamics (MD) based approaches to understand the toxic potential of quinone metabolites of Bisphenol F (BPF) and 3,3'-dimethylbisphenol A (DMBPA). The obtained results indicate a similar chemical reactivity profile for these metabolites of bisphenols to BPA metabolite. MD simulation revealed that the quinone metabolites tend to interact with the DNA comprising hydrogen bonding, van der Waals forces, and electrostatic interactions as an onset for covalent binding to adduct formation. Structural analysis suggests that interactions with DC9, DG10, DG16, DA17, DA18, and DT19 play a crucial role in stabilizing the quinone metabolite in the interactive pocket of DNA. These observations are demonstrating that BPF and DMBPA have the potential to impose genotoxicity via forming the quinone metabolite adducts. Combination of DFT and MD-based computational approaches providing a structure-activity-toxicity spectrum of chemicals can serve for the purpose of risk assessment.

Association of bisphenol A, bisphenol F, and bisphenol S with ADHD symptoms in children

BACKGROUND

Bisphenol A (BPA) has been linked to attention-deficit/hyperactivity disorder (ADHD) symptoms, but the neurotoxic effects of bisphenol substitutes such as bisphenol F (BPF) and S (BPS) have not been well investigated. We investigated the associations between BPA, BPF, and BPS with ADHD symptoms at multiple time points in children.

METHODS

The levels of BPA (at ages 4, 6, and 8), BPF (at ages 6 and 8), and BPS (at ages 6 and 8) were measured in 619 children. Because of the low detection frequency of BPF and BPS levels, participants were divided into categories (<or ≥ limit of detection (LOD) for BPF; < LOD, ≥ LOD and < median, or ≥ median for BPS). ADHD symptoms were assessed using the ADHD Rating Scale IV (ARS). The relationship between bisphenols and ARS scores was analyzed using Poisson regression models, and generalized additive models and piecewise regression models were further explored for BPA.

RESULTS

BPA was detected in most participants (>97%), whereas BPF and BPS were less frequently detected (age 6: 17.5% for BPF and 42.0% for BPS; age 8: 51.6% for BPF and 73.3% for BPS). Doubling in BPA levels was associated with increased ARS scores by 4.7% (95% confidence intervals [CI]: 0.5, 9.2) at age 6. The association was greater with BPA levels higher than 3.0 μg/g creatinine (24.2% [95% CI: 15.5, 33.6] increase). The BPF ≥ LOD group had 10.8% (95% CI: 1.2, 21.4) higher ARS scores than the BPF < LOD group. The BPS ≥ median group had 11.4% (95% CI: 2.0, 21.7) higher ARS scores than the BPS < LOD group.

CONCLUSION

All bisphenols, in particular those at or above the LOD or median levels, were associated with ADHD symptoms at age 6. Further prospective studies are warranted to determine causal inference.

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.