An Evaluation of the Relationship among Urine, Air, and Hand Measures of Exposure to Bisphenol A (BPA) in US Manufacturing Workers

Health risks of Bisphenol-A exposure: From Wnt signaling perspective

Human beings are routinely exposed to chronic and low dose of Bisphenols (BPs) due to their widely pervasiveness in the environment. BPs hold similar chemical structures to 17β-estradiol (E2) and thyroid hormone, thus posing threats to human health by rendering the endocrine system dysfunctional. Among BPs, Bisphenol-A (BPA) is the best-known and extensively studied endocrine disrupting compound (EDC). BPA possesses multisystem toxicity, including reproductive toxicity, neurotoxicity, hepatoxicity and nephrotoxicity. Particularly, the central nervous system (CNS), especially the developing one, is vulnerable to BPA exposure. This review describes our current knowledge of BPA toxicity and the related molecular mechanisms, with an emphasis on the role of Wnt signaling in the related processes. We also discuss the role of oxidative stress, endocrine signaling and epigenetics in the regulation of Wnt signaling by BPA exposure. In summary, dysfunction of Wnt signaling plays a key role in BPA toxicity and thus can be a potential target to alleviate EDCs induced damage to organisms.

Bisphenol analogues in infant foods in south China and implications for infant exposure

Bisphenol analogues (BPs) are commonly used as modifiers, stabilizers and photo-initiators in polymer materials, including those used in food packaging. Compared to adults, infants are more sensitive to chemicals because their bodies are growing and not fully developed. Therefore, it is essential to determine the concentrations of BPs in common infant foods to assess infant exposure and prevent hazards. We collected 54 infant formula (IF) samples, 90 complementary food (CMF) samples and 62 breastmilk samples from breastfeeding women in south China. Tandem mass spectrometry coupled to liquid chromatography separation (HPLC-MS/MS) was used to detect the concentrations of 8 BPs in the three types of food samples. The estimated daily intake (EDI) of infants was also assessed. The results showed that the detection frequency of bisphenol F (BPF), bisphenol S (BPS), bisphenol AF (BPAF) and bisphenol AP (BPAP) were relatively high among the different infant foods. BPF, BPP and BPS were predominant among the detected BPs. The lowest 95th EDI for BPA was 0.67 ng kg-bw-1 day-1, exceeding the tolerable daily intake (TDI) limit for BPA set by the European Food Safety Authority in 2023. Thus, BP exposure is a significant risk to infants. More attention should be paid to the presence of BPs in daily use products and food, and intake limits should be set for BPs other than BPA.

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.

Direct degradation of Bisphenol A from aqueous solution by active red mud in aerobic environment

As industrial waste from aluminum production, red mud (RM) poses a severe threat to the local environment that needs to be appropriately utilized. The activation of iron oxide, which is abundant in RM, improves its effectiveness as a catalytic material for the degradation of organic pollutants. This study developed a novel activation approach by adding dithionite citrate bicarbonate (DCB) for Bisphenol A (BPA) degradation under aeration conditions. Electrochemical experiments and reactive oxygen species (ROSs) trapping experiments showed that DCB treatment enhanced the redox cycle of Fe(II)/Fe(III), which promoted free radical generation. The optimized condition for the RM activation was achieved at 21 mmol/L dithionites, 84 mmol/L citrates, and 34 mmol/L bicarbonate, and the degradation of BPA by activated RM reached 410 µg BPA per gram of RM. This work provided a feasible way to utilize RM resources as an efficient, low-cost catalyst for organic pollutants treatment.

The associations between concentrations of gestational bisphenol analogues and thyroid related hormones in cord blood: A prospective cohort study

Animal studies indicated that Bisphenol analogues (BPs) exhibited potential thyroid toxicity. However, little is known of the associations between maternal BPs exposure and offspring's thyroid related hormones in humans. On the basis of Shanghai-Minhang Birth Cohort study, we analyzed BPs in maternal urine collected at the third trimester of pregnancy. Thyroid related hormones (THs), including total triiodothyronine (TT3), free triiodothyronine (FT3), total thyroxine (TT4), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) were measured in cord blood samples. We performed multiple linear regression and Bayesian kernel machine regression (BKMR) models to explore the single and joint effects of gestational BPs exposure on thyroid related hormones in cord blood among 258 mother-child pairs. Statistically significant inverse associations of categorized BPA with FT3 and TT4 concentrations were observed. We also found a significant association between the mixture of BPs in maternal urine and increased concentration of TT3 in cord blood and a marginally significant association between BPs mixture and increased FT3 concentrations. Further associations of BPA with lower TT4/FT4 and of Bisphenol AF (BPAF) with higher TT3/FT3 were also suggestive, by BKMR model, when other BPs were fixed at 25th percentiles. It was concluded that prenatal BPs exposure was associated with THs in cord blood. Exposure to BPA and BPAF might have large contributions to the effects on thyroid function than other bisphenols.

Zaki M, M. Al-Qahtani S, Fayad E, T. Salem E, K. Abdulsahib W, Emam H, M. Hassan H. Integration of Ultrastructural and Computational Approaches Reveals the Protective Effect of Astaxanthin against BPA-Induced Nephrotoxicity

BACKGROUND

Bisphenol A (BPA) is an environmental contaminant that can induce deleterious organ effects. Human Cytochrome P450 CYP2C9 enzyme belongs to the essential xenobiotic-metabolizing enzymes, producing ROS as a byproduct. Astaxanthin (ATX) is a powerful antioxidant that protects organs and tissues from the damaging effects of oxidative stress caused by various diseases.

AIM OF THE STUDY

This study investigated the possible protective impacts of ATX against BPA-induced nephrotoxicity and its underlying mechanism.

MATERIALS AND METHODS

Kidney tissues were isolated and examined microscopically from control, protected, and unprotected groups of rats to examine the potential protective effect of ATX against nephrotoxicity. Moreover, a molecular dynamic (MD) simulation was conducted to predict the performance of ATX upon binding to the active site of P450 CYP2C9 protein receptor as a potential mechanism of ATX protective effect.

RESULTS

Implemented computational methods revealed the possible underlying mechanism of ATX protection; the protective impact of ATX is mediated by inhibiting P450 CYP2C9 through binding to its dimeric state where the RMSF value for apo-protein and ATX-complex system were 5.720.57 and 1.040.41, respectively, implicating the ATX-complex system to have lesser variance in its residues, leading to the prevention of ROS excess production, maintaining the oxidant-antioxidant balance and re-establishing the proper mitochondrial functionality. Furthermore, the experimental methods validated in silico outcomes and revealed that ATX therapy effectively restored the typical histological architecture of pathological kidney tissues.

CONCLUSIONS

ATX prevents BPA-induced nephrotoxicity by controlling oxidative imbalance and reversing mitochondrial dysfunction. These outcomes shed new light on the appropriate use of ATX as a treatment or prophylactic agent for these severe conditions.

Silicone wristbands as personal passive sampling devices: Current knowledge, recommendations for use, and future directions

Personal chemical exposure assessment is necessary to determine the frequency and magnitude of individual chemical exposures, especially since chemicals present in everyday environments may lead to adverse health outcomes. In the last decade, silicone wristbands have emerged as a new chemical exposure assessment tool and have since been utilized for assessing personal exposure to a wide range of chemicals in a variety of populations. Silicone wristbands can be powerful tools for quantifying personal exposure to chemical mixtures in a single sample, associating exposure with health outcomes, and potentially overcoming some of the challenges associated with quantifying the chemical exposome. However, as their popularity grows, it is crucial that they are used in the appropriate context and within the limits of the technology. This review serves as a guide for researchers interested in utilizing silicone wristbands as a personal exposure assessment tool. Along with briefly discussing the passive sampling theory behind silicone wristbands, this review performs an in-depth comparison of wristbands to other common exposure assessment tools, including biomarkers of exposure measured in biospecimens, and evaluates their utility in exposure assessments and epidemiological studies. Finally, this review includes recommendations for utilizing silicone wristbands to evaluate personal chemical exposure and provides suggestions on what research is needed to recognize silicone wristbands as a premier chemical exposure assessment tool.

Human skin responses to environmental pollutants: A review of current scientific models

Whatever the exposure route, chemical, physical and biological pollutants modify the whole organism response, leading to nerve, cardiac, respiratory, reproductive, and skin system pathologies. Skin acts as a barrier for preventing pollutant modifications. This review aims to present the available scientific models, which help investigate the impact of pollution on the skin. The research question was "Which experimental models illustrate the impact of pollution on the skin in humans?" The review covered a period of 10 years following a PECO statement on in vitro, ex vivo, in vivo and in silico models. Of 582 retrieved articles, 118 articles were eligible. In oral and inhalation routes, dermal exposure had an important impact at both local and systemic levels. Healthy skin models included primary cells, cell lines, co-cultures, reconstructed human epidermis, and skin explants. In silico models estimated skin exposure and permeability. All pollutants affected the skin by altering elasticity, thickness, the structure of epidermal barrier strength, and dermal extracellular integrity. Some specific models concerned wound healing or the skin aging process. Underlying mechanisms were an exacerbated inflammatory skin reaction with the modulation of several cytokines and oxidative stress responses, ending with apoptosis. Pathological skin models revealed the consequences of environmental pollutants on psoriasis, atopic dermatitis, and tumour development. Finally, scientific models were used for evaluating the safety and efficacy of potential skin formulations in preventing the skin aging process or skin irritation after repeated contact. The review gives an overview of scientific skin models used to assess the effects of pollutants. Chemical and physical pollutants were mainly represented while biological contaminants were little studied. In future developments, cell hypoxia and microbiota models may be considered as more representative of clinical situations. Models considering humidity and temperature variations may reflect the impact of these changes.

The exposome in practice: an exploratory panel study of biomarkers of air pollutant exposure in Chinese people aged 60-69 years (China BAPE Study)

The exposome overhauls conventional environmental health impact research paradigms and provides a novel methodological framework that comprehensively addresses the complex, highly dynamic interplays of exogenous exposures, endogenous exposures, and modifiable factors in humans. Holistic assessments of the adverse health effects and systematic elucidation of the mechanisms underlying environmental exposures are major scientific challenges with widespread societal implications. However, to date, few studies have comprehensively and simultaneously measured airborne pollutant exposures and explored the associated biomarkers in susceptible healthy elderly subjects, potentially resulting in the suboptimal assessment and management of health risks. To demonstrate the exposome paradigm, we describe the rationale and design of a comprehensive biomarker and biomonitoring panel study to systematically explore the association between individual airborne exposure and adverse health outcomes. We used a combination of personal monitoring for airborne pollutants, extensive human biomonitoring, advanced omics analysis, confounding information, and statistical methods. We established an exploratory panel study of Biomarkers of Air Pollutant Exposure in Chinese people aged 60-69 years (China BAPE), which included 76 healthy residents from a representative community in Jinan City, Shandong Province. During the period between September 2018 and January 2019, we conducted prospective longitudinal monitoring with a 3-day assessment every month. This project: (1) leveraged advanced tools for personal airborne exposure monitoring (external exposures); (2) comprehensively characterized biological samples for exogenous and endogenous compounds (e.g., targeted and untargeted monitoring) and multi-omics scale measurements to explore potential biomarkers and putative toxicity pathways; and (3) systematically evaluated the relationships between personal exposure to air pollutants, and novel biomarkers of exposures and effects using exposome-wide association study approaches. These findings will contribute to our understanding of the mechanisms underlying the adverse health impacts of air pollution exposures and identify potential adverse clinical outcomes that can facilitate the development of effective prevention and targeted intervention techniques.

miRNA changes in the mouse placenta due to bisphenol A exposure

Aim: To determine small RNA expression changes in mouse placenta induced by bisphenol A (BPA) exposure. Methods: Exposing female mice to BPA two weeks prior to conception through gestational day 12.5; whereupon fetal placentas were collected, frozen in liquid nitrogen and stored at -80°C. Small RNAs were isolated and used for small RNA-sequencing. Results: 43 small RNAs were differentially expressed. Target mRNAs were closely aligned to those expressed by thymus and brain, and pathway enrichment analyses indicated that such target mRNAs regulate neurogenesis and associated neurodevelopment processes. Conclusions: BPA induces several small RNAs in mouse placenta that might provide biomarkers for BPA exposure. Further, the placenta might affect fetal brain development through the secretion of miRNAs.

Urinary bisphenol levels in plastic industry workers

Bisphenol A (BPA) is a known endocrine disruptor compound that is widely applied as a monomer base in polycarbonate plastics and as a binding agent in several epoxy resins. Plastic industry workers have usually heavier and prolonged exposures to BPA. Hence, the present work aims to assess the levels of BPA and their analogs (S, F, B, AF, Z, E, and AP) in 170 urine samples from a cross-sectional study of workers from a plastic industry located in north Constantine (Algeria). This work was complemented with a questionnaire about sexual functions and evaluation of sexual hormone levels. The results showed a stable presence of BPA (average of 3.24 μg/L), accounting for more than 90% of the total BPs. Of the remaining BP analogs, only trace amounts of BPB were detected in three samples (average of 2.73 μg/L). Significant associations with BPA urinary levels were noted with age (p = 0.006), occupational level of exposure (p = 0.023), and years of experience (p = 0.001).

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.

Transcriptomics and Other Omics Approaches to Investigate Effects of Xenobiotics on the Placenta

The conceptus is most vulnerable to developmental perturbation during its early stages when the events that create functional organ systems are being launched. As the placenta is in direct contact with maternal tissues, it readily encounters any xenobiotics in her bloodstream. Besides serving as a conduit for solutes and waste, the placenta possesses a tightly regulated endocrine system that is, of itself, vulnerable to pharmaceutical agents, endocrine disrupting chemicals (EDCs), and other environmental toxicants. To determine whether extrinsic factors affect placental function, transcriptomics and other omics approaches have become more widely used. In casting a wide net with such approaches, they have provided mechanistic insights into placental physiological and pathological responses and how placental responses may impact the fetus, especially the developing brain through the placenta-brain axis. This review will discuss how such omics technologies have been utilized to understand effects of EDCs, including the widely prevalent plasticizers bisphenol A (BPA), bisphenol S (BPS), and phthalates, other environmental toxicants, pharmaceutical agents, maternal smoking, and air pollution on placental gene expression, DNA methylation, and metabolomic profiles. It is also increasingly becoming clear that miRNA (miR) are important epigenetic regulators of placental function. Thus, the evidence to date that xenobiotics affect placental miR expression patterns will also be explored. Such omics approaches with mouse and human placenta will assuredly provide key biomarkers that may be used as barometers of exposure and can be targeted by early mitigation approaches to prevent later diseases, in particular neurobehavioral disorders, originating due to placental dysfunction.

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.

Bisphenol S and bisphenol F are less disruptive to cardiac electrophysiology, as compared to bisphenol A

Bisphenol A (BPA) is a high-production volume chemical used to manufacture consumer and medical-grade plastic products. Due to its ubiquity, the general population can incur daily environmental exposure to BPA, while heightened exposure has been reported in intensive care patients and industrial workers. Due to health concerns, structural analogues are being explored as replacements for BPA. This study aimed to examine the direct effects of BPA on cardiac electrophysiology compared with recently developed alternatives, including BPS (bisphenol S) and BPF (bisphenol F). Whole-cell voltage-clamp recordings were performed on cell lines transfected to express the voltage-gated sodium channel (Nav1.5), L-type voltage-gated calcium channel (Cav1.2), or the rapidly activating delayed rectifier potassium channel (hERG). Cardiac electrophysiology parameters were measured using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) and intact, whole rat heart preparations. BPA was the most potent inhibitor of fast/peak (INa-P) and late (INa-L) sodium channel (IC50= 55.3, 23.6 µM, respectively), L-type calcium channel (IC50= 30.8 µM) and hERG channel current (IC50= 127 µM). Inhibitory effects on L-type calcium channels were supported by microelectrode array recordings, which revealed a shortening of the extracellular field potential (akin to QT interval). BPA and BPF exposures slowed atrioventricular (AV) conduction and increased AV node refractoriness in isolated rat heart preparations, in a dose-dependent manner (BPA: +9.2% 0.001 µM, +95.7% 100 µM; BPF: +20.7% 100 µM). BPS did not alter any of the cardiac electrophysiology parameters tested. Results of this study demonstrate that BPA and BPF exert an immediate inhibitory effect on cardiac ion channels, while BPS is markedly less potent. Additional studies are necessary to fully elucidate the safety profile of bisphenol analogues on the heart.

Fighting Bisphenol A-Induced Male Infertility: The Power of Antioxidants

Bisphenol A (BPA), a well-known endocrine disruptor present in epoxy resins and polycarbonate plastics, negatively disturbs the male reproductive system affecting male fertility. In vivo studies showed that BPA exposure has deleterious effects on spermatogenesis by disturbing the hypothalamic–pituitary–gonadal axis and inducing oxidative stress in testis. This compound seems to disrupt hormone signalling even at low concentrations, modifying the levels of inhibin B, oestradiol, and testosterone. The adverse effects on seminal parameters are mainly supported by studies based on urinary BPA concentration, showing a negative association between BPA levels and sperm concentration, motility, and sperm DNA damage. Recent studies explored potential approaches to treat or prevent BPA-induced testicular toxicity and male infertility. Since the effect of BPA on testicular cells and spermatozoa is associated with an increased production of reactive oxygen species, most of the pharmacological approaches are based on the use of natural or synthetic antioxidants. In this review, we briefly describe the effects of BPA on male reproductive health and discuss the use of antioxidants to prevent or revert the BPA-induced toxicity and infertility in men.

Bisphenol A and Its Analogues in Chinese Total Diets: Contaminated Levels and Risk Assessment

Bisphenol A (BPA) and its analogues (BPs) are suspected posing potential endocrine disrupting properties. They might migrate into foodstuffs through food packaging materials or contaminated water and soil. Dietary exposure is of paramount importance way for human health. European Food Safety Authority (EFSA) lowered the value of tolerable daily intake (TDI) from 50 μg/kg bw/day (d) to a temporary (t) TDI (t-TDI) of 4 μg/kg bw/d. In this study, the Chinese total dietary samples were analyzed for assessing the exposure risk of BPs by diets. BPA, bisphenol F (BPF), bisphenol S (BPS), and bisphenol AF (BPAF) were found in 12 kinds of food samples except for bisphenol B (BPB). A deterministic approach was used to calculate the dietary intakes of 4 kinds of compounds. For different age and gender groups, the exposure levels of BPA (178.440-403.672 ng/kg bw/d) was the highest, followed by BPS (21.372-52.112 ng/kg bw/d), BPF (20.641-50.507 ng/kg bw/d), and BPAF (0.434-1.210 ng/kg bw/d). Based on the t-TDI set by EFSA (4 μg/kg bw/d for BPA), the BPs through dietary intake pose low risks on the Chinese general population even summarization exposure levels of different BPs. However, human can be exposed to multiple endocrine disrupting chemicals rather than BPs alone; combined exposure risks should be further considered.

Bisphenol A and its analogues: A comprehensive review to identify and prioritize effect biomarkers for human biomonitoring

Human biomonitoring (HBM) studies have demonstrated widespread and daily exposure to bisphenol A (BPA). Moreover, BPA structural analogues (e.g. BPS, BPF, BPAF), used as BPA replacements, are being increasingly detected in human biological matrices. BPA and some of its analogues are classified as endocrine disruptors suspected of contributing to adverse health outcomes such as altered reproduction and neurodevelopment, obesity, and metabolic disorders among other developmental and chronic impairments. One of the aims of the H2020 European Human Biomonitoring Initiative (HBM4EU) is the implementation of effect biomarkers at large scales in future HBM studies in a systematic and standardized way, in order to complement exposure data with mechanistically-based biomarkers of early adverse effects. This review aimed to identify and prioritize existing biomarkers of effect for BPA, as well as to provide relevant mechanistic and adverse outcome pathway (AOP) information in order to cover knowledge gaps and better interpret effect biomarker data. A comprehensive literature search was performed in PubMed to identify all the epidemiologic studies published in the last 10 years addressing the potential relationship between bisphenols exposure and alterations in biological parameters. A total of 5716 references were screened, out of which, 119 full-text articles were analyzed and tabulated in detail. This work provides first an overview of all epigenetics, gene transcription, oxidative stress, reproductive, glucocorticoid and thyroid hormones, metabolic and allergy/immune biomarkers previously studied. Then, promising effect biomarkers related to altered neurodevelopmental and reproductive outcomes including brain-derived neurotrophic factor (BDNF), kisspeptin (KiSS), and gene expression of nuclear receptors are prioritized, providing mechanistic insights based on in vitro, animal studies and AOP information. Finally, the potential of omics technologies for biomarker discovery and its implications for risk assessment are discussed. To the best of our knowledge, this is the first effort to comprehensively identify bisphenol-related biomarkers of effect for HBM purposes.

Bisphenols and phthalates: Plastic chemical exposures can contribute to adverse cardiovascular health outcomes

Phthalates and bisphenols are high production volume chemicals that are used in the manufacturing of consumer and medical products. Given the ubiquity of bisphenol and phthalate chemicals in the environment, biomonitoring studies routinely detect these chemicals in 75-90% of the general population. Accumulating evidence suggests that such chemical exposures may influence human health outcomes, including cardiovascular health. These associations are particularly worrisome for sensitive populations, including fetal, infant and pediatric groups-with underdeveloped metabolic capabilities and developing organ systems. In the presented article, we aimed to review the literature on environmental and clinical exposures to bisphenols and phthalates, highlight experimental work that suggests that these chemicals may exert a negative influence on cardiovascular health, and emphasize areas of concern that relate to vulnerable pediatric groups. Gaps in our current knowledge are also discussed, so that future endeavors may resolve the relationship between chemical exposures and the impact on pediatric cardiovascular physiology.

Exposure to environmental bisphenol A inhibits HTR-8/SVneo cell migration and invasion

Environmental pollutants, such as bisphenol A (BPA) have recently been implicated in the development of adverse birth outcomes. However, the underlying teratogenic mechanisms remain unclear. We investigated the effects of BPA on the migration and invasion of human primary extravillous trophoblast HTR-8/SVneo cells. Our results indicated that BPA reduced cell migration and invasion. Moreover, it altered the ratio of matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) by downregulating MMP-2 and MMP-9, and upregulating TIMP-1 and TIMP-2. Furthermore, BPA suppressed integrin β1, integrin α5, and vimentin. Interestingly, BPA-induced invasion was partially restored by G15, a membrane G-protein-coupled estrogen receptor 30 antagonist. We further revealed that 42 proteins were differentially expressed by mass spectrometry analysis, which could be divided into three categories based on gene ontology including biological process, cellular component, and molecular function. These results suggest that BPA reduces HTR-8/SVneo cell migration and invasion by downregulating MMP-2 and MMP-9, up-regulating TIMP-1 and TIMP-2, and suppressing adhesion molecules.

Bisphenol A and Male Fertility: Myths and Realities

Bisphenol A (BPA) represents the main chemical monomer of epoxy resins and polycarbonate plastics. The environmental presence of BPA is widespread, and it can easily be absorbed by the human body through dietary and transdermal routes, so that more than 90% of the population in western countries display detectable BPA levels in the urine. As BPA is qualified as an endocrine disruptor, growing concern is rising for possible harmful effects on human health. This review critically discusses the available literature dealing with the possible impact of BPA on male fertility. In rodent models, the in vivo exposure to BPA negatively interfered with the regulation of spermatogenesis throughout the hypothalamic-pituitary-gonadal axis. Furthermore, in in vitro studies, BPA promoted mitochondrial dysfunction and oxidative/apoptotic damages in spermatozoa from different species, including humans. To date, the claimed clinical adverse effects on male fertility are largely based on the results from studies assessing the relationship between urinary BPA concentration and conventional semen parameters. These studies, however, produced controversial evidence due to heterogeneity in the extent of BPA exposure, type of population, and enrollment setting. Moreover, the cause-effect relationship cannot be established due to the cross-sectional design of the studies as well as the large spontaneous between- and within-subject variability of semen parameters. The best evidence of an adverse effect of BPA on male fertility would be provided by prospective studies on clinically relevant endpoints, including natural or medically assisted pregnancies among men either with different exposure degrees (occupational/environmental) or with different clinical conditions (fertile/subfertile).

Bisphenol A and bisphenol S disruptions of the mouse placenta and potential effects on the placenta-brain axis

Placental trophoblast cells are potentially at risk from circulating endocrine-disrupting chemicals, such as bisphenol A (BPA). To understand how BPA and the reputedly more inert bisphenol S (BPS) affect the placenta, C57BL6J mouse dams were fed 200 μg/kg body weight BPA or BPS daily for 2 wk and then bred. They continued to receive these chemicals until embryonic day 12.5, whereupon placental samples were collected and compared with unexposed controls. BPA and BPS altered the expression of an identical set of 13 genes. Both exposures led to a decrease in the area occupied by spongiotrophoblast relative to trophoblast giant cells (GCs) within the junctional zone, markedly reduced placental serotonin (5-HT) concentrations, and lowered 5-HT GC immunoreactivity. Concentrations of dopamine and 5-hydroxyindoleacetic acid, the main metabolite of serotonin, were increased. GC dopamine immunoreactivity was increased in BPA- and BPS-exposed placentas. A strong positive correlation between 5-HT+ GCs and reductions in spongiotrophoblast to GC area suggests that this neurotransmitter is essential for maintaining cells within the junctional zone. In contrast, a negative correlation existed between dopamine+ GCs and reductions in spongiotrophoblast to GC area ratio. These outcomes lead to the following conclusions. First, BPS exposure causes almost identical placental effects as BPA. Second, a major target of BPA/BPS is either spongiotrophoblast or GCs within the junctional zone. Third, imbalances in neurotransmitter-positive GCs and an observed decrease in docosahexaenoic acid and estradiol, also occurring in response to BPA/BPS exposure, likely affect the placental-brain axis of the developing mouse fetus.

Fetal bisphenol A and ethinylestradiol exposure alters male rat urogenital tract morphology at birth: Confirmation of prior low-dose findings in CLARITY-BPA

Bisphenol A (BPA) is a contaminant in virtually all Americans. To examine BPA's adverse effects, the FDA-NCTR, NIEHS, and 14 groups of academic scientists formed a consortium: CLARITY-BPA. The purpose of our study was to investigate the effects of a wide range of doses of BPA on fetal development of the NCTR CD-SD male rat urogenital sinus (UGS). Pregnant rats were administered BPA or positive control ethinylestradiol (EE2) daily, via oral gavage, from gestational day 6 through parturition. Tissues were collected on postnatal day 1 and the UGS was analyzed using computer-assisted 3-D reconstruction. Importantly, only low doses of BPA, as well as EE2, significantly changed birth weight and UGS morphology, including an increased size of the colliculus and decreased size of the urethra, consistent with prior reported BPA and EE2 effects. Our findings provide further evidence that BPA mediates nonmonotonic developmental effects on the fetal urogenital sinus.

Endocrine disruption through membrane estrogen receptors and novel pathways leading to rapid toxicological and epigenetic effects

Estrogen binding to estrogen receptors (ESR) triggers signaling cascades within cells. Historically, a major emphasis has been characterizing estrogen-induced genomic actions resulting from binding to nuclear estrogen receptor 1 (nESR1). However, recent evidence indicates the first receptors estrogens encounter as they enter a cell, membrane ESR1 (mESR1), also play crucial roles. Membrane and nuclear ESR are derived from the same transcripts but the former are directed to the membrane via palmitoylation. Binding and activation of mESR1 leads to rapid fluctuations in cAMP and Ca+2 and stimulation of protein kinase pathways. Endocrine disrupting chemicals (EDC) that mimic 17β-estradiol can signal through mESR1 and elicit non-genomic effects. Most current EDC studies have focused on genomic actions via nESR1. However, increasing number of studies have begun to examine potential EDC effects mediated through mESR1, and some EDC might have higher potency for signaling through mESR1 than nESR1. The notion that such chemicals might also affect mESR1 signaling via palmitoylation and depalmitoylation pathways has also begun to gain currency. Recent development of transgenic mice that lack either mESR1 or nESR1, while retaining functional ESR1 in the other compartment, will allow more precise in vivo approaches to determine EDC effects through nESR1 and/or mESR1. It is increasingly becoming apparent in this quickly evolving field that EDC directly affect mESR and estrogen signaling, but such chemicals can also affect proportion of ESR reaching the membrane. Future EDC studies should be designed to consider the full range of effects through mESR alone and in combination with nESR.