Bisphenols as a Legacy Pollutant, and Their Effects on Organ Vulnerability

Bisphenols are widely used in the synthesis of polycarbonate plastics, epoxy resins, and thermal paper, which are used in manufacturing items of daily use. Packaged foods and drinks are the main sources of exposure to bisphenols. These chemicals affect humans and animals by disrupting the estrogen, androgen, progesterone, thyroid, and aryl hydrocarbon receptor functions. Bisphenols exert numerous harmful effects because of their interaction with receptors, reactive oxygen species (ROS) formation, lipid peroxidation, mitochondrial dysfunction, and cell signal alterations. Both cohort and case-control studies have determined an association between bisphenol exposure and increased risk of cardiovascular diseases, neurological disorders, reproductive abnormalities, obesity, and diabetes. Prenatal exposure to bisphenols results in developmental disorders in animals. These chemicals also affect the immune cells and play a significant role in initiating the inflammatory response. Exposure to bisphenols exhibit age, gender, and dose-dependent effects. Even at low concentrations, bisphenols exert toxicity, and hence deserve a critical assessment of their uses. Since bisphenols have a global influence on human health, the need to discover the underlying pathways involved in all disease conditions is essential. Furthermore, it is important to promote the use of alternatives for bisphenols, thereby restricting their uses.

Related papers:

title: Bisphenol A and human health: a review of the literature.
abstract: There is growing evidence that bisphenol A (BPA) may adversely affect humans. BPA is an endocrine disruptor that has been shown to be harmful in laboratory animal studies. Until recently, there were relatively few epidemiological studies examining the relationship between BPA and health effects in humans. However, in the last year, the number of these studies has more than doubled. A comprehensive literature search found 91 studies linking BPA to human health; 53 published within the last year. This review outlines this body of literature, showing associations between BPA exposure and adverse perinatal, childhood, and adult health outcomes, including reproductive and developmental effects, metabolic disease, and other health effects. These studies encompass both prenatal and postnatal exposures, and include several study designs and population types. While it is difficult to make causal links with epidemiological studies, the growing human literature correlating environmental BPA exposure to adverse effects in humans, along with laboratory studies in many species including primates, provides increasing support that environmental BPA exposure can be harmful to humans, especially in regards to behavioral and other effects in children.

title: Release of Bisphenol A from Polycarbonate—A Review
abstract: The release of Bisphenol A (BPA) from polycarbonate baby bottles into food and food simulants is reviewed in the perspective of the current intensive discussions on the risks of this substance. Potential factors that have been reported to influence the release of BPA are reviewed. Unlike most polymers polycarbonate is hydrolyzed under alkaline conditions by scale formation, residual alkaline detergents and boiled water. Data suggest that brushing of the bottle did not raise the release of BPA. Claims that used bottles release more BPA than new bottles and that mineral composition of the aqueous food simulant affect release could not be substantiated. There are indications that aminolysis of polycarbonate by milk and ethanolysis of polycarbonate by 50% ethanol might take place under relevant test conditions. The relatively few migration data following the test conditions of European food contact material legislation, comply with the specific migration limit. Two test conditions were identified that reflect real use and exposure, and might cause higher release of BPA compared to the test conditions of European food contact material legislation. Further detailed studies are necessary to verify whether these two exposure scenarios are more severe.

title: Bisphenol A (BPA) in China: a review of sources, environmental levels, and potential human health impacts.
abstract: Bisphenol A (BPA), identified as an endocrine disruptor, is an industrially important chemical that is used as a raw material in the manufacture of many products such as engineering plastics (e.g., epoxy resins/polycarbonate plastics), food cans (i.e., lacquer coatings), and dental composites/sealants. The demand and production capacity of BPA in China have grown rapidly. This trend will lead to much more BPA contamination in the environmental media and in the general population in China. This paper reviews the current literature concerning the pollution status of BPA in China (the mainland, Hong Kong, and Taiwan) and its potential impact on human health. Due to potential human health risks from long-term exposure to BPA, body burden of the contaminant should be monitored.

title: Assessment of bisphenol A alternatives in paper products from the Chinese market and their dermal exposure in the general population.
abstract: Bisphenol A (BPA), a well-known endocrine disruptor, is used as a color developer in thermal paper. More recently, some emerging structural analogues have been introduced to replace BPA due to the strengthened regulations concerning thermal paper. Nevertheless, very limited data are available regarding their occurrence and potential health risks. Here, thirteen potentially toxic compounds were investigated in paper products (120 thermal papers and 81 nonthermal papers) collected in Beijing, China. The results indicated that the replacement of BPA by alternatives such as Bisphenol S (BPS), Bis(2-chloroethyl)ether-4,4″-dihydroxydiphenyl sulfone copolymer (D-90), 4-hydroxyphenyl 4-isoprooxyphenylsulfone (D-8), Bis(4-hydroxyphenyl)sulfonylphenyl (BPS-MAE) and Bis-(3-allyl-4-hydroxyphenyl) sulfone (TGSA) has been significantly advanced in several types of thermal paper (i.e., market weight stickers, train tickets, express labels, air boarding passes and lottery tickets). The mean value for the total analyte concentrations in thermal paper was 6.06 mg/g, and the highest level found was 26.0 mg/g. In addition, the frequent detection of these chemicals in nonthermal paper (>80%, n = 81) demonstrated that the contamination in thermal paper can be spread into other recycled paper, such as corrugated boxes, newspapers, food contact papers, etc. The estimated daily intake of BPA and its alternatives through the handling of thermal paper was 0.025 μg/kg bw/day for the general population. This is the first report on the occurrence of various new BPA alternatives in paper products from China, which will be helpful for further risk assessment and making responsible replacement decisions.

title: Bisphenol A Analogues in Food and Their Hormonal and Obesogenic Effects: A Review
abstract: Bisphenol A (BPA) is the most well-known compound from the bisphenol family. As BPA has recently come under pressure, it is being replaced by compounds very similar in structure, but data on the occurrence of these BPA analogues in food and human matrices are limited. The main objective of this work was to investigate human exposure to BPA and analogues and the associated health effects. We performed a literature review of the available research made in humans, in in vivo and in vitro tests. The findings support the idea that exposure to BPA analogues may have an impact on human health, especially in terms of obesity and other adverse health effects in children.

title: Assessment of human exposure to Bisphenol-A, Triclosan and Tetrabromobisphenol-A through indoor dust intake in Belgium.
abstract: Bisphenol-A (BPA), Triclosan (TCS) and Tetrabromobisphenol-A (TBBPA) are phenolic organic contaminants used in a variety of household applications. Through manufacture and usage, these contaminants can leach into the environment and can be detected in indoor dust. In this study, we determined the concentrations of BPA, TCS and TBBPA in indoor dust samples from 18 houses and 2 offices in Flanders, Belgium. The analysis was performed using solid-liquid extraction, clean-up and measurement by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Median concentrations of the 18 domestic dust samples were 1460, 220 and 10 ng g(-1) dust for BPA, TCS and TBBPA, respectively. Concentrations in offices were almost 5-10 times higher for BPA and TBBPA, while TCS concentrations were comparable at both locations. An assessment of the daily intake of these contaminants through dust was made and the contribution of dust to the total human exposure was calculated. For all three contaminants, dust seems to be a minor contributor (<10% of total exposure) to the total daily exposure. Food intake appears to be the major source of human exposure to BPA and TBBPA as dermal uptake through personal care products seems to be the major contributor for TCS.

title: Occupational Exposure Levels of Bisphenol A among Chinese Workers
abstract: Occupational Exposure Levels of Bisphenol A among Chinese Workers: Yonghua He, et al. School of Public Health/WHO Collaborating Center for Occupational Health, Fudan University, PR China

title: Transcriptional Analysis of Chlorella pyrenoidosa Exposed to Bisphenol A
abstract: Bisphenol A (BPA) is the raw material of 71% of polycarbonate-based resins and 27% of epoxy-based resins which are used for coating metal-based food and beverage cans. Meanwhile, it is taken into account as a typical environmental pollutant. Hormesis may occur in algae exposed to BPA. In this study, the effects of BPA on Chlorella pyrenoidosa were assessed based on growth inhibition and transcriptome analysis. We have focused on two exposure scenarios as follows: (1) exposure to a low stimulation concentration (0.1 mg.L−1, 19.35% promotion in cell density on the 3rd day); (2) exposure to a high inhibition concentration (10 mg.L−1, 64.71% inhibition in cell density on the 3rd day). Transcriptome analysis showed enrichment in nucleotide transport, single-organism transport, cellular respiration. Among them, adenosine triphosphate (ATP) synthase and Nicotinamide adenine dinucleotide (NADH) dehydrogenase were upregulated under 0.1 mg.L−1 BPA treatment. These changes enhanced the physiological and energy metabolic pathways of C. pyrenoidosa, thereby stimulating cell proliferation. At exposure to the high BPA, severe inhibited changes in the expression levels of several pathways were observed, which were related to tricarboxylic acid (TCA) cycle, glycolysis, fatty acid metabolism, oxidative phosphorylation, and photosynthesis. Therefore, BPA could negatively affect growth inhibition through the multiple energy metabolism processes. These results may result in a deeper insight into BPA-induced biphasic responses in algae, and provide vital information to assess the potential ecological risks of exposure to BPA in an aquatic ecosystem.

title: Case study: Is bisphenol S safer than bisphenol A in thermal papers?
abstract: The Risk Assessment Committee of the European Chemical Agency released a scientific opinion alerting that the risk associated with dermal occupational exposure to bisphenol A (BPA) via thermal paper might not be adequately controlled because the estimated exposure was around twice the Derived No Effect Level (DNEL) and the European Commission will effectively restrict BPA in thermal paper as soon as 2020. Bisphenol S (BPS) is currently being used as a BPA surrogate and is already widespread in thermal paper receipts. Based on publically available information in the scientific literature, we assessed the risk associated with dermal BPS exposure via thermal paper for the general and occupational populations to compare with BPA situation. We developed two exposure scenarios; one based on the total excreted BPS and another on exposure estimations by transferring BPS from the thermal paper matrix to skin. Both scenarios yielded similar exposures for the general population (0.016–0.013 µg/kg bw/day), but the exposure estimated for the workers in the second scenario (0.96 µg/kg bw/day) was around 17-fold higher than that estimated for the workers in the first scenario. The systemic DNELs for the general and workers populations were 0.45 and 0.91 µg BPS/kg bw/day, respectively, which were 4.6- and 19-fold higher than the respective dermal DNELs. Risk Characterisation Ratio (RCR) (estimated exposure through urinary excretion compared with the systemic DNEL) in the first and most reliable scenario suggested that the risk was adequately controlled. In the second scenario, however, the RCR suggests that the risk might not be adequately controlled for both the general population and workers. This work raises the necessity of generate more toxicodynamic and toxicokinetic information, specially using dermal exposures, to properly assess the risk associated to dermal BPS exposure because the situation might presumably get worse after 2020.

title: QUANTITATION OF BISPHENOL A AND BISPHENOL A GLUCURONIDE IN BIOLOGICAL SAMPLES BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY
abstract: Bisphenol A (BPA) is a weak estrogen. Pharmacokinetic studies of BPA have demonstrated a rapid and extensive metabolism of BPA to the nonestrogenic BPA-monoglucuronide (BPA-gluc). Some investigators have reported that BPA was found at parts per billion concentrations in the tissues or urine of humans without known exposure to BPA. This work developed a rapid and sensitive method for the determination of BPA and BPA-gluc in plasma and urine based on liquid chromatography-tandem mass spectrometry. The liquid chromatography-electrospray ionization-tandem mass spectrometry method for quantitation of BPA and BPA-gluc uses stable isotope-labeled internal standards. A linear ion trap mass spectrometer permits identification and quantitation of BPA-gluc and BPA without sample workup. Development of separation conditions reduced the BPA-background in solvent samples to below 2.5 pmol/ml for BPA. Limit of quantitation (LOQ) for BPA in control urine was 15 pmol/ml; LOQ for BPA-gluc was 65 pmol/ml. Application of the method to urine samples from human subjects (n = 6) after administration of 25 μg of BPA/person (estimated maximum human daily intake) permitted the determination of excretion kinetics for BPA-gluc; BPA was below the LOD in all except two of the samples. In urine or blood samples of human subjects (n = 19) without intentional exposure to BPA, BPA concentrations were always below the limit of detection (≈2.5 pmol/ml) with or without prior glucuronidase treatment. The results show that care is required for analysis of BPA and its major metabolite BPA-gluc. The LOD obtained and the absence of detectable levels of BPA in samples from individuals suggests that general exposure of humans to BPA is much lower than the worst-case exposure scenario developed.

title: Binary Mixtures of Selected Bisphenols in the Environment: Their Toxicity in Relationship to Individual Constituents
abstract: Bisphenol A (BPA) is one of the most popular and commonly used plasticizer in the industry. Over the past decade, new chemicals that belong to the bisphenol group have increasingly been used in industrial applications as alternatives to BPA. Nevertheless, information on the combined effects of bisphenol (BP) analogues is insufficient. Therefore, our current study aimed to find the biological response modulations induced by the binary mixtures of BP compounds. We determined the toxicity levels in Microtox and XenoScreen YES/YAS assays for several BP analogs alone, and for their binary mixtures. The results obtained constituted the database for chemometric intelligent data analysis to evaluate the possible interactions occurring in the mixtures. Several chemometric/biophysical models have been used (concentration addition—CA, independent action—IA and polynomial regression calculations) to realize this aim. The best fitting was found for the IA model and even in this description strong evidence for synergistic behaviors (modes of action) of some bisphenol analogue mixtures was demonstrated. Bisphenols A, S, F and FL were proven to be of significant endocrine threat (with respect to XenoScreen YES/YAS assay); thus, their presence in mixtures (including presence in tissues of living organisms) should be most strictly monitored and reported.

title: Bisphenol A and Metabolic Syndrome: Results from NHANES
abstract: Bisphenol A (BPA) is detected in the urine of >95% of US adults. Recent evidence from population-based studies suggests that BPA is associated with individual components for metabolic syndrome (MetS). However, no previous study has examined the direct association between BPA and MetS.  We examined 2,104 participants from the National Health and Nutrition Examination Survey 2003–2008. The main outcome was the presence of MetS (n = 741).  Increasing levels of urinary BPA were positively associated with MetS, independent of confounders such as age, gender, race/ethnicity, smoking, alcohol intake, physical activity, and urinary creatinine. Compared to tertile 1 (referent), the multivariable adjusted odds ratio (95% confidence interval) of MetS in tertile 3 was 1.51 (1.07–2.12); P-trend was 0.02.  Urinary BPA levels are positively associated with MetS, in a representative sample of US adults and independent of traditional risk factors for MetS. Future, prospective studies are needed to confirm our findings.

title: Embryotoxic and teratogenic effects of the combination of bisphenol A and genistein on in vitro cultured postimplantation rat embryos.
abstract: The potential teratogenic effects and fetal toxicity of environmental estrogenic endocrine disruptors have become a great concern in recent years, and they have yet to be fully characterized. In the present study, the teratogenic effects of bisphenol A (BPA) and genistein (GEN) on rat embryos during their critical period of organogenesis were investigated using a whole-embryo culture experiment. The combined exposure effects of BPA and GEN were explored using a 4 x 4 full factorial design. Both BPA and GEN produced concentration-dependent inhibition of embryonic development, beginning at 32.0 and 10.0 microg/ml, respectively. Full factorial and isobologram analyses revealed a significant synergistic interaction between BPA and GEN for most end points (12 out of 20 tested), as indicated by the enhanced developmental toxicity of BPA after coexposure with different dose levels of GEN. In particular, serious malformations and a higher abnormal frequency of the central nervous system were induced by the combination of BPA and GEN. Our findings suggest that GEN may be embryotoxic and teratogenic to humans. BPA alone may not be a potential teratogen, but these two estrogenic chemicals have a synergistic effect on embryonic development when present together during the critical period of major organ formation. The current findings suggest that pregnant women should not take soy supplements, but more studies are necessary to provide a conclusive recommendation.

title: The occurrence, potential toxicity, and toxicity mechanism of bisphenol S, a substitute of bisphenol A: A critical review of recent progress.
abstract: Bisphenol S (BPS) has been introduced into the industry as a safer alternative to bisphenol A (BPA). The distribution of BPS has recently become an important issue worldwide, but investigations on the toxicity and mechanisms of BPS remain limited. A review of the literature reveals that BPS has widespread presence in environmental media, such as indoor dust, surface water, sediments, and sewage sludge. It has been detected in plants, paper products, some food items, and even in the human body. In addition, compared to BPA, BPS has a lower acute toxicity, similar or less endocrine disruption, similar neurotoxicity and immunotoxicity, and lower reproductive and developmental toxicity. The mechanisms underlying BPS toxicity may be related to the chemical properties of BPS in the human body, including interactions with estrogen receptors, and binding to DNA and some proteins, subsequently including exerting oxidative stress. However, further investigation on the potential risks of BPS to humans and its mechanisms of toxicity should be conducted to better understand and control the risks of such novel chemicals.

title: Occurrence of bisphenol S in the environment and implications for human exposure: A short review.
abstract: As a substitute of bisphenol A (BPA), bisphenol S (BPS) has been applied in consumer products present in our daily lives. With a similar chemical structure as BPA, BPS has also been demonstrated as an exogenous endocrine disrupting chemical. Compared with a large number of studies on BPA, investigation on BPS has remained limited. In this study, we reviewed the literature of BPS mainly published during 2010-2017, including its environmental distributions, toxicities, and human exposure. The data demonstrated that BPS is now ubiquitous in the environment and found worldwide, but generally with concentration levels lower than BPA in various environment media, including water, sediment, sludge, indoor dust and air, consumer products, and human urine. However, we found that the concentration levels of BPS in aquatic environments, especially water samples, were almost comparable or equal to that of BPA. Our summary also indicated that process speed of substituting BPA with BPS in consumer products in the U.S. was relatively faster than other countries. In addition, we summarized the toxicities of exposure to BPS both in vivo and in vitro experiments. The current data supports that exposure to BPS may have adverse effects on reproductive systems, endocrine systems, and nervous systems in animals and humans, and may trigger oxidative stress. The occurrence of BPS was frequently reported in human urine, but rarely in other human samples. The current research indicates that food is the dominant source for human exposure to BPS, and the contribution of personal care product usage is low. The occurrence of BPS and their metabolites in the human body and the guidelines for BPS exposure merit further investigation.

title: Environmentally Relevant Concentrations of Bisphenol A Interact with Doxorubicin Transcriptional Effects in Human Cell Lines
abstract: The worldwide production of synthetic chemicals, including endocrine disruptor chemicals (EDCs), such as Bisphenol A (BPA) has increased significantly in the last two decades. Human exposure to BPA, particularly through ingestion, is continuous and ubiquitous. Although, considered a weak environmental estrogen, BPA can induce divergent biological responses through several signaling pathways, including carcinogenesis in hormone-responsive organs. However, and despite the continuous increase of tumor cell-resistance to therapeutic drugs, such as doxorubicin (DOX), information regarding BPA drug interactions is still scarce, although its potential role in chemo-resistance has been suggested. This study aims to assess the potential interactions between environmentally relevant levels of BPA and DOX at a therapeutic dosage on Hep-2 and MRC-5 cell lines transciptome. Transcriptional effects in key-player genes for cancer biology, namely c-fos, p21, and bcl-xl, were evaluated through qRT-PCR. The cellular response was analyzed after exposure to BPA, DOX, or co-exposure to both chemicals. Transcriptional analysis showed that BPA exposure induces upregulation of bcl-xl and endorses an antagonistic non-monotonic response on DOX transcriptional effects. Moreover, the BPA interaction with DOX on c-fos and p21 expression emphasize its cellular specificity and divergent effects. Overall, Hep-2 was more susceptible to BPA effects in a dose-dependent manner while MRC-5 transcriptional levels endorsed a non-monotonic response. Our data indicate that BPA environmental exposure may influence chemotherapy outcomes, which emphasize the urgency for a better understanding of BPA interactions with chemotherapeutic agents, in the context of risk assessment.

title: Bisphenol Analogues Other Than BPA: Environmental Occurrence, Human Exposure, and Toxicity-A Review.
abstract: Numerous studies have investigated the environmental occurrence, human exposure, and toxicity of bisphenol A (BPA). Following stringent regulations on the production and usage of BPA, several bisphenol analogues have been produced as a replacement for BPA in various applications. The present review outlines the current state of knowledge on the occurrence of bisphenol analogues (other than BPA) in the environment, consumer products and foodstuffs, human exposure and biomonitoring, and toxicity. Whereas BPA was still the major bisphenol analogue found in most environmental monitoring studies, BPF and BPS were also frequently detected. Elevated concentrations of BPAF, BPF, and BPS (i.e., similar to or greater than that of BPA) have been reported in the abiotic environment and human urine from some regions. Many analogues exhibit endocrine disrupting effects, cytotoxicity, genotoxicity, reproductive toxicity, dioxin-like effects, and neurotoxicity in laboratory studies. BPAF, BPB, BPF, and BPS have been shown to exhibit estrogenic and/or antiandrogenic activities similar to or even greater than that of BPA. Knowledge gaps and research needs have been identified, which include the elucidation of environmental occurrences, persistence, and fate of bisphenol analogues (other than BPA), sources and pathways for human exposure, effects on reproductive systems and the mammary gland, mechanisms of toxicity from coexposure to multiple analogues, metabolic pathways and products, and the impact of metabolic modification on toxicity.

title: Developmental exposure of zebrafish (Danio rerio) to bisphenol-S impairs subsequent reproduction potential and hormonal balance in adults.
abstract: In the recent years, there has been a growing concern about the production and use of bisphenol-A substitute, namely bisphenol-S (BPS). Due to its novel nature, there have been few studies addressing the ability of BPS to disrupt the endocrine system of animals. In the present study, zebrafish (Danio rerio) embryos were exposed to and reared in various concentrations of BPS (0, 0.1, 1, 10 and 100 μg/l) for 75 days. Then adult males and females were paired in spawning tanks for 7 days in clean water and the consequent effects on fish development, reproduction, plasma vitellogenin (VTG), sex steroids and thyroid hormone levels were investigated as endpoints. After 75 days of exposure, there was a skewed sex ratio in favor of females. The results also showed that body length and weight significantly decreased in males exposed to 100 μg/l of BPS. Gonadosomatic index was significantly reduced in fish at ≥ 10 μg/l. Hepatosomatic index exhibited a significant increase in both male and female fish. At ≥ 1 μg/l of BPS, plasma 17β-estradiol levels were significantly increased in both males and females. However, plasma testosterone showed a significant reduction in males exposed to 10 and 100 μg/l of BPS. A significant induction in plasma VTG level was observed in both males and females at ≥ 10 μg/l of BPS. Plasma thyroxine and triiodothyronine levels were significantly decreased at 10 and 100 μg/l of BPS in males, and at 100 μg/l in females. Egg production and sperm count were also significantly decreased in groups received 10 and 100 μg/l of BPS. Moreover, once time to hatching and hatching rates were calculated for fertilized eggs the postponed and decreased rates of hatching were observed. Taken together, these results suggest that developmental exposure to low concentrations of BPS has adverse effects on different parts of the endocrine system in zebrafish.

title: Are structural analogues to bisphenol a safe alternatives?
abstract: Bisphenol A (BPA) is a chemical with widespread human exposure suspected of causing low-dose effects. Thus, a need for developing alternatives to BPA exists. Structural analogues of BPA have already been detected in foods and humans. Due to the structural analogy of the alternatives, there is a risk of effects similar to BPA.



The aim was to elucidate and compare the hazards of bisphenol B (BPB), bisphenol E (BPE), bisphenol F (BPF), bisphenol S (BPS) and 4-cumylphenol (HPP) to BPA.



In vitro studies on steroidogenesis, receptor activity, and biomarkers of effect, as well as Quantitative Structure-Activity Relationship (QSAR) modeling.



All test compounds caused the same qualitative effects on estrogen receptor and androgen receptor activities, and most of the alternatives exhibited potencies within the same range as BPA. Hormone profiles for the compounds indicated a specific mechanism of action on steroidogenesis which generally lead to decreased androgen, and increased estrogen and progestagen levels. Differential effects on corticosteroid synthesis were observed suggesting a compound-specific mechanism. Overall, BPS was less estrogenic and antiandrogenic than BPA, but BPS showed the largest efficacy on 17α-hydroxyprogesterone (17α-OH progesterone). Finally, there were indications of DNA damage, carcinogenicity, oxidative stress, effects on metabolism, and skin sensitization of one or more of the test compounds.



Interference with the endocrine system was the predominant effect of the test compounds. A substitution of BPA with these structural analogues should be carried out with caution.

title: Cellular, transcriptomic and methylome effects of individual and combined exposure to BPA, BPF, BPS on mouse spermatocyte GC‐2 cell line
abstract: Environmental factors, particularly xenoestrogens adversely affect reproductive health and their main mechanism is based on steroid‐signaling pathway alterations. The presence of bisphenol A (BPA) in the environment has been confirmed and it is about to be replaced by analogues such as bisphenol F (BPF) and bisphenol S (BPS). Whether the BPF and BPS exert similar adverse effects to BPA has become the subject of intense scientific scrutiny. The aim of the present study was to evaluate and compare the cellular, transcriptomic and methylome effects of exposure to BPA, BPF, BPS individually and in combination on GC‐2 spermatocyte cell line. The results show that all studied compounds affect cell viability, induce apoptosis and cause cellular damage. BPA, BPF and BPS also influence GC‐2 cell steroid receptor and steroidogenesis related genes expressions. In addition to specific molecular mechanisms, all studied compounds also increase global DNA methylation. Exposure to a combination of all the studied compounds caused comparable effects on cell culture to each of them examined separately. These data suggest that exposure to BPA and its main substitutes‐ BPF and BPS induced multitude of effects and hence, BPF and BPS are not safe alternative to BPA in terms of male reproductive health. HIGHLIGHTSBPA, BPF and BPS affect GC‐2 cell viabilityERs and GPR30 cooperate in mediating the effects of BPF and BPSMixture of bisphenols causes comparable effects as single compound.BPA, BPF and BPS affect global DNA methylation.BPF and BPS are not safe substitutes to BPA.

title: Impact of low-dose chronic exposure to bisphenol A and its analogue bisphenol B, bisphenol F and bisphenol S on hypothalamo-pituitary-testicular activities in adult rats: A focus on the possible hormonal mode of action.
abstract: Bisphenol A an estrogen-mimic endocrine disrupting chemical, used to manufacture polycarbonate plastics and epoxy resins with toxic effects for male reproduction. Due to its toxicity, industries have started to replace it with other bisphenols. In this study, the toxicity of BPA analogues (BPB, BPF and BPS) was evaluated in a chronic study. We investigated whether the chronic exposure to low bisphenols doses affects spermatogenesis with outcomes on oxidative stress and male reproductive system. Male rats (22 day old) were exposed to water containing 0.1% ethanol for control or different concentrations of BPA and its analogues BPB, BPF and BPS (5, 25 and 50 μg/L) in drinking water for 48 weeks. Results of the present study showed a significant alteration in the gonadosomatic index (GSI) and relative reproductive organs weights. Oxidative stress in the testis was significantly elevated while sperm motility, Daily sperm production (DSP) and number of sperm in epididymis were reduced. Plasma testosterone, LH and FSH concentrations were reduced and estradiol levels were high in 50 μg/L exposed group. These results suggest that exposure to BPA and its analogues for chronic duration can induce structural changes in testicular tissue and endocrine alterations in the male reproductive system.

title: Effects of bisphenol A analogues on reproductive functions in mice.
abstract: This study was performed to examine whether bisphenol (BP) A analogues, BPE and BPS, negatively impacts reproductive functions using mice as a model. CD-1 mice were exposed to control treatment (corn oil), BPA, BPE and BPS (50μg/kg or 10mg/kg) from birth to postnatal day (PND) 60 by s.c. injection every three days. Sperm counts or motility was significantly reduced by BPA, BPE or BPS exposure on PND 60 or PND 90. Exposure of BPA, BPE and BPS disrupted the progression of germ cell development, as morphometric analyses exhibited an abnormal distribution of the stages of spermatogenesis. In females, postnatal BPA and BPE exposure accelerated the onset of puberty, and increased body weight after parturition. Furthermore, postnatal exposure of BPA, BPE and/or BPS increased steroid hormone levels in serum. These results suggest that BPA analogues (BPS and BPE) affects male and female reproductive functions.

title: Bisphenol-A induced oxidative stress, inflammatory gene expression, and metabolic and histopathological changes in male Wistar albino rats: protective role of boron.
abstract: Bisphenol A (BPA) is one of the most produced chemicals in the world and has been widely employed in the food industry. Continuous and widespread exposure to BPA through drinking water and food leads to health concerns for humans. This study evaluated the effects of boron (B) on BPA-mediated oxidative stress in male Wistar albino rats. Rats were equally divided into 5 groups; corn oil was given orally to the control group; 25 mg kg-1 of BPA dissolved in corn oil was given orally to the second group. All other groups received the same dose of BPA and different doses of B (5, 10, and 20 mg kg-1 per day, respectively) orally for 30 days. The administration of BPA significantly decreased glutathione levels and increased malondialdehyde levels in rat tissues. Furthermore, BPA treatment reduced the catalase and superoxide dismutase activities in tissues and erythrocytes. Also, mRNA expression levels of TNF-α, IL-1β, and IL-6 in the brain, liver, and testes of rats were augmented, whereas IL-10 was decreased with BPA treatment. Besides, BPA treatment adversely altered biochemical parameters and caused damage to the cell integrity of rat tissues. However, B administration reversed BPA-induced alterations in rat tissues in a dose-dependent manner. Furthermore, B exhibited antioxidant and anti-inflammatory effects and regulated metabolic and histopathological alterations in male Wistar albino rats exposed to BPA.

title: Prenatal Exposure to Bisphenol A Analogues on Male Reproductive Functions in Mice
abstract: This study was performed to examine whether prenatal exposure to bisphenol (BP) A analogues, BPE and BPS, negatively impacts male reproductive functions and testis development using mice as a model. CD-1 mice were orally exposed to control treatment (corn oil), BPA, BPE, and BPS (0.5, 20, or 50 µg/kg/day) from gestational day 11 (the presence of vaginal plug = 1) to birth. Although sperm counts were significantly reduced by BPA, BPE, or BPS on postnatal day (PND) 60, only BPE or BPS exposure remained low for sperm motility. Exposure to BPA, BPE, and BPS disrupted the progression of germ cell development, as morphometric analyses exhibited an abnormal distribution of the stages of spermatogenesis. Furthermore, BPS with a dose of 50 µg/kg/day increased a level of serum estradiol-17β in adult males. On PND12, BPE and BPS significantly increased TUNEL positive cells in neonatal testis, following disruption of the expression of apoptosis, autophagy, and oxidative stress-related factors. In addition, the expression of methyltransferases for DNA methylation and histone modification was also affected by prenatal exposure to BPA, BPE, or BPS in neonatal testis. These results suggest that prenatal exposure to BPE and BPS with physiologically relevant doses affects male reproductive functions probably due to spermatogenic defect in the developing testis.

title: Bisphenol S modulates concentrations of bisphenol A and oestradiol in female and male mice
abstract: Concern over endocrine-disrupting actions of bisphenol A (BPA) has prompted some manufacturers to remove it from consumer products. Among the chemical replacements in “BPA-free” products are other bisphenol analogues, such as bisphenol S (BPS). Given evidence that BPA and BPS possess similar oestrogenic activity, their capacity to interact and disrupt oestrogen homeostasis should be examined. We investigated whether BPS can modulate concentrations of 14C-BPA, exogenous 3H-oestradiol (E2), or natural E2. CF-1 mice were each given a single subcutaneous injection of oil containing 0 (vehicle), 1, 3, or 9 mg BPS, then given a dietary supplement containing either 50 μg/kg 14C-BPA or 5 μCi (14.5 ng) 3H-E2. BPS treatment elevated 14C-BPA concentrations in blood serum and certain reproductive organs of both sexes, but reduced 3H-E2 concentrations in blood serum of females. In another experiment, natural E2 was measured in urine 2–12 h after injection of 0 (vehicle), 1, or 3 mg BPS. BPS reduced E2 concentrations at 10 h after injection in both sexes. These results are consistent with evidence that BPS and BPA compete for access to metabolic enzymes, and that BPS can disrupt oestrogen homeostasis. These findings demonstrate the importance of considering multiple toxicants when determining regulatory exposure limits.

title: Binding of bisphenol A, bisphenol AF, and bisphenol S on the androgen receptor: Coregulator recruitment and stimulation of potential interaction sites.
abstract: Bisphenol A (BPA), bisphenol AF (BPAF), and bisphenol S (BPS) are well known endocrine disruptors. Previous in vitro studies showed that these compounds antagonize androgen receptor (AR) transcriptional activity; however, the mechanisms of action are unclear. In the present study, we investigated interactions of coregulator peptides with BPA, BPAF, or BPS at the AR complexes using Micro Array for Real-time Coregulator Nuclear Receptor Interaction (MARCoNI) assays and assessed the binding of these compounds on AR by molecular dynamics (MD) simulations. The set of coregulator peptides that are recruited by BPA-bound AR, either positively/or negatively, are different from those recruited by the agonist R1881-bound AR. Therefore, the data indicates that BPA shows no similarities to R1881 and suggests that it may recruit other coregulators to the AR complex. BPAF-bound AR recruits about 70-80% of the same coregulator peptides as BPA-bound AR. Meanwhile, BPS-bound AR interacts with only few peptides compared to BPA or BPAF-bound AR. MD results show that multiple binding sites with varying binding affinities are available on AR for BPA, BPAF, and BPS, indicating the availability of modified binding surfaces on AR for coregulator interactions. These findings help explain some of the distinct AR-related toxicities observed with bisphenol chemicals and raise concern for the use of substitutes for BPA in commercial products.

title: Bisphenol A Exposure and Sperm ACHE Hydroxymethylation in Men
abstract: Exposure to bisphenol A (BPA) has been shown to impact human sperm quality. The epigenetic mechanisms underlying the effect remain unknown. The acetylcholinesterase (ACHE) gene is a sperm-expressed gene encoding the acetylcholine hydrolyzing enzyme acetylcholinesterase and participates in the apoptosis of cells, including sperm. This study aimed to examine whether BPA exposure is associated with the hydroxymethylation level of the sperm ACHE gene. A total of 157 male factory workers were studied, among whom 74 had BPA exposure in the workplace (BPA exposure group) and 83 had no BPA exposure in the workplace (control group). Urine samples were collected for BPA measurement and semen samples were collected to assay for ACHE hydroxymethylation. Sperm ACHE hydroxymethylation level was higher in the BPA exposure group (p = 0.041) compared to the control group. When subjects were categorized according to tertiles of detected BPA level, higher ACHE hydroxymethylation levels were observed for the lowest, middle, and top tertiles compared to those with BPA below the limit of detection (LOD). In a linear regression analysis adjusted for confounders, a positive linear association between urine BPA concentration and 5-hydroxymethylcytosine (5hmC) rate of the sperm ACHE gene was observed, although the association did not reach statistical significance in all categories after being stratified by the BPA tertile. In conclusion, 5hmC of the sperm ACHE gene was positively associated with BPA exposure, which may provide supportive evidence for BPA’s effects on male fertility or other health endpoints.

title: Bisphenol-A and the great divide: a review of controversies in the field of endocrine disruption.
abstract: In 1991, a group of 21 scientists gathered at the Wingspread Conference Center to discuss evidence of developmental alterations observed in wildlife populations after chemical exposures. There, the term "endocrine disruptor" was agreed upon to describe a class of chemicals including those that act as agonists and antagonists of the estrogen receptors (ERs), androgen receptor, thyroid hormone receptor, and others. This definition has since evolved, and the field has grown to encompass hundreds of chemicals. Despite significant advances in the study of endocrine disruptors, several controversies have sprung up and continue, including the debate over the existence of nonmonotonic dose response curves, the mechanisms of low-dose effects, and the importance of considering critical periods of exposure in experimental design. One chemical found ubiquitously in our environment, bisphenol-A (BPA), has received a tremendous amount of attention from research scientists, government panels, and the popular press. In this review, we have covered the above-mentioned controversies plus six additional issues that have divided scientists in the field of BPA research, namely: 1) mechanisms of BPA action; 2) levels of human exposure; 3) routes of human exposure; 4) pharmacokinetic models of BPA metabolism; 5) effects of BPA on exposed animals; and 6) links between BPA and cancer. Understanding these topics is essential for educating the public and medical professionals about potential risks associated with developmental exposure to BPA and other endocrine disruptors, the design of rigorously researched programs using both epidemiological and animal studies, and ultimately the development of a sound public health policy.

title: Bisphenol-A acts as a potent estrogen via non-classical estrogen triggered pathways
abstract: Bisphenol-A (BPA) is an estrogenic monomer commonly used in the manufacture of numerous consumer products such as food and beverage containers. Widespread human exposure to significant doses of this compound has been reported. Traditionally, BPA has been considered a weak estrogen, based on its lower binding affinity to the nuclear estrogen receptors (ERs) compared to 17-β estradiol (E2) as well as its low transcriptional activity after ERs activation. However, in vivo animal studies have demonstrated that it can interfere with endocrine signaling pathways at low doses during fetal, neonatal or perinatal periods as well as in adulthood. In addition, mounting evidence suggests a variety of pathways through which BPA can elicit cellular responses at very low concentrations with the same or even higher efficiency than E2. Thus, the purpose of the present review is to analyze with substantiated scientific evidence the strong estrogenic activity of BPA when it acts through alternative mechanisms of action at least in certain cell types.

title: Bisphenol A exposure, effects, and policy: a wildlife perspective.
abstract: Thousands of anthropogenic chemicals are present in the environment, and mounting evidence indicates that some have endocrine-disrupting effects in a variety of organisms. Of particular concern are chemicals that act as agonists or antagonists on vertebrate estrogen or androgen receptors. One such compound is bisphenol A (BPA), which appears to be both an estrogen receptor agonist and an androgen receptor antagonist. Used in the manufacture of plastic resins, BPA is found at low levels in surface-water, sediments, soils, and biota. Although it degrades quickly, it is pseudo-persistent in the environment because of continual inputs. Due to its environmental ubiquity, organisms may be exposed to BPA chronically or during sensitive life stages. While the impacts of BPA-related endocrine disruption in humans have been extensively studied, the endocrinal and systemic effects in wildlife are less well known. This article reviews the current state of knowledge of BPA inputs to the environment, routes of exposure, and effects on wildlife. We then critically examine the regulatory structure governing the environmental endpoints of BPA in the United States, European Union, and Canada, and discuss major challenges to the effective regulation of BPA. We conclude with a survey of treatment and mitigation options.

title: Exposure to Bisphenol a Substitutes and Gestational Diabetes Mellitus: A Prospective Cohort Study in China
abstract: The association of bisphenol A (BPA) and gestational diabetes mellitus (GDM) has been investigated in only a small number of studies, and research on the associations between BPA substitutes and GDM is scarce.  We aimed to investigate the associations of four bisphenols [bisphenol A (BPA), bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF)] levels in urine sample with the risk of gestational diabetes mellitus (GDM) and plasma glucose levels.  A total of 1,841 pregnant women from a cohort study were recruited at their first prenatal examination between 2013 and 2015 in Wuhan, China. Concentrations of four bisphenols (BPA, BPS, BPF, BPAF) were measured in first-trimester urine samples using Ultra-high performance liquid chromatography system coupled to a Triple Quadrupole mass spectrometer (UHPLC-TQMS). An oral glucose tolerance test (OGTT) was performed at 24–28 gestational weeks and GDM was diagnosed post hoc using International Association of Diabetes and Pregnancy Study Groups criteria. We used multivariable logistic regression models to examine the associations of urinary bisphenols with the risk of GDM, and multiple linear regression models to determine the associations between bisphenols exposure and plasma glucose levels.  Urinary BPAF was associated with increased odds of GDM among women with normal pre-pregnancy BMI [adjusted odds ratio (aOR) = 1.70 (95% CI: 1.08, 2.67) for the highest group compared to the lowest group], and the association remained significant after additional adjustment for other bisphenols [aOR = 1.68 (95% CI: 1.03, 2.72)]. No significant associations were observed for other bisphenols and GDM. Consistent with the result of GDM, women in the highest BPAF category had a mean of 0.05 mmol/L (95% CI: 0.01, 0.09) higher fasting plasma glucose (FPG) levels than women in the lowest category. For BPA and plasma glucose, non-linear associations were observed between urinary BPA and FPG and the sum of the PG z-score among women who were overweight (p for non-linear association < 0.05). We also found that the per-unit increase in natural log transformed specific gravity adjusted BPS [ln (SG-adj BPS)] was associated with a 0.03 mmol/L (95% CI: 0.01, 0.04) increase in FPG levels and the associations might be modified by fetal sex (p for interaction < 0.05). Among women with female fetus, a per-unit increase in ln (SG-adj BPS) was associated with a 0.04 mmol/L (95% CI: 0.02, 0.06) increase in FPG, a 0.11 mmol/L (95% CI: 0.04, 0.17) increase in 1 h-PG and a 0.19 mmol/L (95% CI: 0.08, 0.30) increase in the sum of PG z-score.  Our results provide evidence that BPAF and BPS might be potential risk factors of GDM, which require to be studied further.

title: Urinary bisphenol A concentrations in relation to serum thyroid and reproductive hormone levels in men from an infertility clinic.
abstract: Human exposure to bisphenol A (BPA) is widespread. Animal studies have demonstrated that BPA can alter endocrine function, but human studies are limited. For the present study, we measured urinary BPA concentrations and serum thyroid and reproductive hormone levels in 167 men recruited through an infertility clinic. BPA was detected in 89% of urine samples with a median (range) of 1.3 (<0.4 - 36.4) ng/mL. In multivariable regression models adjusted for potential confounders, BPA concentrations in urine collected on the same day as a blood sample were inversely associated with serum levels of inhibin B and estradiol:testosterone ratio (E(2):T) and positively associated with follicle-stimulating hormone (FSH) and FSH:inhibin B ratio. Because BPA is metabolized quickly and multiple urine measures may better reflect exposure than a single measure, we also considered among a subset of the men the BPA concentrations in repeated urine samples collected weeks or months following serum sample collection. In these analyses, the effect estimates remained consistent for FSH and E(2):T but were somewhat weakened for inhibin B. In addition, we observed inverse relationships between urinary BPA concentrations and free androgen index (ratio of testosterone to sex hormone binding globulin), estradiol, and thyroid stimulating hormone. Our results suggest that urinary BPA concentrations may be associated with altered hormone levels in men, but these findings need to be substantiated through further research.

title: Bisphenol A Exposure Is Associated with in Vivo Estrogenic Gene Expression in Adults
abstract: Bisphenol A (BPA) is a synthetic estrogen commonly used in polycarbonate plastic and resin-lined food and beverage containers. Exposure of animal and cell models to doses of BPA below the recommended tolerable daily intake (TDI) of 50 μg/kg/day have been shown to alter specific estrogen-responsive gene expression, but this has not previously been shown in humans.  We investigated associations between BPA exposure and in vivo estrogenic gene expression in humans.  We studied 96 adult men from the InCHIANTI population study and examined in vivo expression of six estrogen receptor, estrogen-related receptor, and androgen receptor genes in peripheral blood leukocytes.  The geometric mean urinary BPA concentration was 3.65 ng/mL [95% confidence interval (CI): 3.13, 4.28], giving an estimated mean excretion of 5.84 μg/day (95% CI: 5.00, 6.85), significantly below the current TDI. In age-adjusted models, there were positive associations between higher BPA concentrations and higher ESR2 [estrogen receptor 2 (ER beta)] expression (unstandardized linear regression coefficient = 0.1804; 95% CI: 0.0388, 0.3221; p = 0.013) and ESRRA (estrogen related receptor alpha) expression (coefficient = 0.1718; 95% CI: 0.0213, 0.3223; p = 0.026): These associations were little changed after adjusting for potential confounders, including obesity, serum lipid concentrations, and white cell subtype percentages. Upper-tertile BPA excretors (urinary BPA > 4.6 ng/mL) had 65% higher mean ESR2 expression than did lower-tertile BPA excretors (0–2.4 ng/mL).  Because activation of nuclear-receptor–mediated pathways by BPA is consistently found in laboratory studies, such activation in humans provides evidence that BPA is likely to function as a xenoestrogen in this sample of adults.

title: Urinary Bisphenol A Concentration and Thyroid Function in Chinese Adults
abstract: Bisphenol A (BPA) is an endocrine disruptor that in animal studies can bind to the thyroid hormone receptor and affect thyroid function. Relevant epidemiologic studies are limited and results are inconsistent. We explored the relationship between urinary BPA and thyroid function in a Chinese population.  The study population included 3394 subjects age 40 years or older who were enrolled in a population-based study from Songnan Community, Baoshan District, Shanghai, China, from June through August 2009. We analyzed the association between urinary BPA and thyroid function using multivariate linear regression. Participants were further divided according to thyroid function status, and logistic regression was applied to determine the relationship between urinary BPA and thyroid function.  Each one-quartile increase in BPA was related to an increase of 0.068 pmol/l (95% confidence interval = 0.065– 0.071) in free triiodothyronine and a 0.084 &mgr;IU/ml decline (−0.099 to −0.069) in thyroid-stimulating hormone (TSH) in men. For women, there was a 0.10 pmol/l (0.09 to 0.11) increase in free triiodothyronine and a 0.13 &mgr;IU/ml decline (−0.14 to −0.11) in TSH. High urinary BPA level was associated with increased thyroid function (adjusted odds ratio= 1.71 [1.26 to 2.32]).  Our results support previous reports of associations between BPA exposure and altered thyroid hormones in animal models and epidemiologic studies. Because our study is cross-sectional, no causal relationships can be established.

title: Determination of four parabens and bisphenols A, F and S in human breast milk using QuEChERS and liquid chromatography coupled to mass spectrometry.
abstract: For the first time, a multiresidue, sensitive and high throughput method for determination of bisphenol A, F and S and 4 parabens (methyl paraben, ethyl paraben, propyl paraben and butyl paraben) in human breast milk was developed. The proposed method includes an extraction and clean-up procedure based on QuEChERS methodology followed by liquid chromatography coupled to triple quadrupole mass spectrometry determination. Negative atmospheric pressure chemical ionization in the selected reaction monitoring mode was used for mass detection. During the method validation the recoveries varied between 83 and 115% with a precision lower than 20% for all analytes using spiked levels from 0.1 to 50 ng mL-1. The LOQ was 0.10 ng mL-1 for most of the analytes. The proposed method was successfully applied for the determination of these compounds in 10 breast milk samples from volunteer lactating mothers from the Valencian region (Spain). Among parabens, methyl paraben presented the highest detection frequency (80%) with a concentration range of 0.11-7.00 ng mL-1, while bisphenol A was detected more frequently than BPF and BPS (80% of detection frequency) with concentrations ranging from 0.13 to 1.62 ng mL-1.

title: Biomonitoring of bisphenols A, F, S in human milk and probabilistic risk assessment for breastfed infants.
abstract: The present study addresses the presence of bisphenols A (BPA) and its analogs bisphenol F (BPF) and S (BPS) in milk of 120 mothers living in Valencia (Spain) and participating in the BETTERMILK project (year 2015). We also studied the factors that could influence the BPA levels and estimated the exposure and the risk for breast fed infants. The frequency of detection of total (conjugated + unconjugated) and unconjugated-BPA were 83% and 77%, with a geometric mean of 0.29 ng/mL and 0.15 ng/mL, respectively. The frequency of detection was much lower for total-BPF (22%) and total-BPS (1.1%). The place of residence of the mother and the use of personal care products showed significant association with BPA concentrations. The estimated daily intake of total-BPA for breastfed infants amounted to a geometric mean of 0.04 μg/kg bw and a 95th percentile of 1.0 μg/kg bw, below the tolerable daily intake of 4 μg/kg bw-day established by EFSA. To our knowledge, this is the largest biomonitoring study of bisphenols in human milk in Europe.

title: Mammalian development in a changing environment: exposure to endocrine disruptors reveals the developmental plasticity of steroid‐hormone target organs
abstract: Recent findings in the field of environmental endocrine disruption have revealed that developmental exposure to estrogenic chemicals induces morphological, functional, and behavioral anomalies associated with reproduction. The aim of the present study was to determine the effects of in utero exposure to low doses of the estrogenic chemical bisphenol A (BPA) on the development of the female reproductive tissues and mammary glands in CD‐1 mice. Humans are exposed to BPA, which leaches from dental materials and plastic food and beverage containers. Here we report that prenatal exposure to BPA induces alterations in tissue organization within the ovaries and mammary glands and disrupts estrous cyclicity in adulthood. Because estrogen receptors are expressed developmentally in these estrogen‐target organs, we propose that BPA may directly affect the expression of genes involved in their morphogenesis. In addition, alterations in the sexual differentiation of the brain, and thus the hypothalamic‐pituitary‐gonadal axis, may further contribute to the observed phenotype. The emerging field of endocrine disruptors promises to provide new insights into the mechanisms underlying the development of hormone‐target organs and demonstrates that the environment plays important roles in the making of phenotypes.

title: Inhibition of catalase activity with 3-amino-1,2,4-triazole intensifies bisphenol A (BPA)-induced toxicity in granulosa cells of female albino rats
abstract: Exposure to bisphenol A (BPA), an endocrine disruptor and environmental toxicant, is associated with adverse estrogenic effects in both humans and wildlife species. Because the effects of BPA on the ovary at the cellular level are incompletely understood, the present study was designed to investigate the underlying mechanism of granulosa cell injury following BPA exposure. Eight-week-old female Wistar rats were treated with BPA (25 mg/kg BW/day for 9 days, intraperitonially) with or without pretreatment of the catalase-specific blocker 3-amino-1,2,4-triazole (ATZ; 1 g/kg BW/day for 5 days, intraperitonially). Different oxidative and antioxidant stress parameters, pro-inflammatory cytokines, and hormonal levels were measured. Catalase expression in isolated granulosa cells was analyzed by Western blot. There were noticeable increases in both nitric oxide and lipid peroxidation levels in the granulosa cells of the BPA-treated group with or without pretreatment with ATZ. Compared with the controls, BPA exposure resulted in a significant increase in pro-inflammatory cytokine levels that was further increased following pretreatment with ATZ. Results of the hormonal assays clearly showed a significant decrease in both estrogen and progesterone levels. In contrast, there was a significant increase in both serum follicle-stimulating hormone and luteinizing hormone levels following BPA exposure, with or without ATZ pretreatment. Results of Western blot analysis demonstrated decreased expression of catalase in the BPA-treated group and a further decrease in expression in the group treated with both BPA and ATZ. Our data suggest that catalase plays a role in mediating reproductive damage to granulosa cells exposed to BPA.

title: Melatonin ameliorates bisphenol A-induced perturbations of the prostate gland of adult Wistar rats.
abstract: Bisphenol A (BPA) is an endocrine disrupting chemical (EDC) that has been demonstrated to induce alterations in reproductive organs while melatonin (ML), an antioxidant, present in plants and animals, is capable of protecting against EDC-induced alterations. Adult male Wistar rats (average weight, 240 + 10 g) were divided into four groups of ten animals each: Rats in group I (control) received oral 0.2 ml 1% dimethyl sulfoxide (DMSO)/99% canola oil as vehicle; group II received intra-peritoneal 10 mg/kg BW/day ML. Group III received oral BPA dissolved in DMSO and solubilized in canola oil at 10 mg/kg BW/day. Group IV were treated with same dose of BPA as group III with a concomitant intra-peritoneal 10 mg/kg BW/day ML. All treatments lasted for 14 days. BPA significantly increased the prostatic index of the rats while ML ameliorated it. BPA significantly increased serum levels of estrogen as well as prostate-specific antigen but decreased serum testosterone in the rats while concomitant treatment with ML ameliorated these alterations. Also, BPA caused vascular congestion, hyperplasia (functional, reactive and atypical) of prostatic epithelium as well as tubular atrophy the rats while ML attenuated the observed lesions. Decreased localization of αSmooth muscle actin, vimentin and S100 proteins were observed in the BPA-treated rats while these decreases were ameliorated by ML. The present study has shown that sub-acute oral administration of BPA induced alterations in prostatic index, serum hormone levels, down-regulated protein localization and induced morphological lesions of the prostate gland in rats while concomitant treatment with intra-peritoneal ML ameliorated these conditions. Hence, low dose of ML can protect against BPA-induced toxicity of the prostate gland of rats.

title: Bisphenol A inhibits cultured mouse ovarian follicle growth partially via the aryl hydrocarbon receptor signaling pathway.
abstract: Bisphenol A (BPA) is an endocrine disruptor that inhibits growth of mouse ovarian follicles and disrupts steroidogenesis at a dose of 438μM. However, the effects of lower doses of BPA and its mechanism of action in ovarian follicles are unknown. We hypothesized that low doses of BPA inhibit follicular growth and decrease estradiol levels through the aryl hydrocarbon receptor (AHR) pathway. Antral follicles from wild-type and Ahr knock-out (AhrKO) mice were cultured for 96h. Follicle diameters and estradiol levels then were compared in wild-type and AhrKO follicles ± BPA (0.004-438μM). BPA inhibited follicle growth (110-438μM) and decreased estradiol levels (43.8-438μM) in wild-type and AhrKO follicles. However, at BPA 110μM, inhibition of growth in AhrKO follicles was attenuated compared to wild-type follicles. These data suggest that BPA may inhibit follicle growth partially via the AHR pathway, whereas its effects on estradiol synthesis likely involve other mechanisms.

title: Bisphenol A induced oxidative stress and apoptosis in mice testes: Modulation by selenium
abstract: Spermatogenesis, a highly coordinated process, is prone to environmental insults which may lead to impaired spermatogenesis or, at worst, infertility. Bisphenol A (BPA) is a well‐known global environmental toxicant and a ubiquitous oestrogenic chemical. This study evaluated the role of selenium (0.5 ppm sodium selenite/kg diet) on spermatogenesis after BPA treatment in different groups of male BALB/c mice: control, selenium, BPA and selenium+BPA. Markers of oxidative stress and apoptosis were evaluated in testis after BPA treatment. Significant decrease in sperm concentration and motility and increased reactive oxygen species(ROS) and LPO levels were seen in BPA group. Histopathological changes revealed extensive vacuolisation, lumen devoid of spermatozoa and decreased germ cell count, confirmed by testicular germ cell count studies. TUNEL assay for apoptosis showed increased number of TUNEL‐positive germ cells in BPA group with increased percentage apoptotic index. However, in Se+BPA group, histopathological studies revealed systematic array of all germ cells, preserved basement membrane with relatively less vacuolisation, improved sperm parameters and ROS and LPO levels and decreased number of TUNEL‐positive germ cells. These results clearly demonstrate the role of selenium in ameliorating oxidative stress and apoptosis induced upon BPA treatment in mice and can be further used as therapeutic target in male infertility.

title: In vitro study on the agonistic and antagonistic activities of bisphenol-S and other bisphenol-A congeners and derivatives via nuclear receptors.
abstract: Bisphenols are a group of chemicals structurally similar to bisphenol-A (BPA) in current use as the primary raw material in the production of polycarbonate and epoxy resins. Some bisphenols are intended to replace BPA in several industrial applications. This is the case of bisphenol-S (BPS), which has an excellent stability at high temperature and resistance to sunlight. Studies on the endocrine properties of BPS have focused on its interaction with human estrogen receptor alpha (hERα), but information on its interaction with other nuclear receptors is scarce. The aim of this study was to investigate interactions of BPS, BPF, BPA and its halogenated derivatives, tetrachlorobisphenol A (TCBPA), and tetrabromobisphenol A (TBBPA), with human estrogen receptors (hERα and hERβ), androgen receptor (hAR), and pregnane X receptor (hPXR), using a panel of in vitro bioassays based on competitive binding to nuclear receptors (NRs), reporter gene expression, and cell proliferation assessment. BPS, BPF, and BPA efficiently activated both ERs, while TCBPA behaved as weak hERα agonist. Unlike BPF and BPA, BPS was more active in the hERβ versus hERα assay. BPF and BPA were full hAR antagonists (BPA>BPF), whereas BPA and BPS were weak hAR agonists. Only BPA, TCBPA, and TBBPA, were hPXR agonists (TCBPA>TBBPA>BPA). These findings provide evidence that BPA congeners and derivatives disrupt multiple NRs and may therefore interfere with the endocrine system. Hence, further research is needed to evaluate the potential endocrine-disrupting activity of putative BPA substitutes.

title: Predicting anti-androgenic activity of bisphenols using molecular docking and quantitative structure-activity relationships.
abstract: Both in vivo and in vitro assay indicated that bisphenols can inhibit the androgen receptor. However, the underlying antagonistic mechanism is unclear. In this study, molecular docking was employed to probe the interaction mechanism between bisphenols and human androgen receptor (hAR). The binding pattern of ligands in hAR crystal structures was also analyzed. Results show that hydrogen bonding and hydrophobic interactions are the dominant interactions between the ligands and hAR. The critical amino acid residues involved in forming hydrogen bonding between bisphenols and hAR is Asn 705 and Gln 711. Furthermore, appropriate molecular structural descriptors were selected to characterize the non-bonded interactions. Stepwise multiple linear regressions (MLR) analysis was employed to develop quantitative structure-activity relationship (QSAR) models for predicting the anti-androgenic activity of bisphenols. Based on the QSAR development and validation guideline issued by OECD, the goodness-of-fit, robustness and predictive ability of constructed QSAR model were assessed. The model application domain was characterized by the Euclidean distance and Williams plot. The mechanisms of the constructed model were also interpreted based on the selected molecular descriptors i.e. the number of hydroxyl groups (nROH), the most positive values of the molecular surface potential (Vs,max) and the lowest unoccupied molecular orbital energy (ELUMO). Finally, based on the model developed, the data gap for other twenty-six bisphenols on their anti-androgenic activity was filled. The predicted results indicated that the anti-androgenic activity of seven bisphenols was higher than that of bisphenol A.

title: Bisphenol AF exerts estrogenic activity in MCF-7 cells through activation of Erk and PI3K/Akt signals via GPER signaling pathway.
abstract: The negative health effects of bisphenol A (BPA) due to its estrogenic activity result in the increasing usage of alternative bisphenols (BPs) including bisphenol AF (BPAF). To comprehensive understand health effects of BPAF, the MCF-7 cells were used to investigate the effects of BPAF on cell proliferation, intracellular reactive oxygen species (ROS) formation, and calcium ion (Ca2+) level. The molecular mechanisms of cell biological responses caused by BPAF were investigated by analyzing target protein expression. The results showed that low-concentration BPAF induces significant effects on MCF-7 cells, including promoting cell proliferation and elevating intracellular ROS and Ca2+ levels. BPAF in low concentration significantly enhances the protein expression of estrogen receptor α (ERα), G protein-coupled receptor (GPER), c-Myc, and Cyclin D1, as well as increases phosphorylation levels of protein kinase B (Akt) and extracellular signal-regulated kinase (Erk) in MCF-7 cells. After the addition of ERα, GPER, and phosphatidylinositide 3-kinase (PI3K) inhibitors, phosphorylations of Erk and Akt were both inhibited. In addition, specific signal inhibitors significantly attenuated the effects of BPAF. Silencing of GPER also markedly decreased BPAF induced cell proliferation. The present results suggested that BPAF can activate PI3K/Akt and Erk signals via GPER, which, in turn, stimulate cellular biological effects induced by BPAF. ERα also plays a critical role in BPAF induced cellular biological effects.

title: Endocrine activity of alternatives to BPA found in thermal paper in Switzerland.
abstract: Alternatives to bisphenol A (BPA) are more and more used in thermal paper receipts. To get an overview of the situation in Switzerland, 124 thermal paper receipts were collected and analyzed. Whereas BPA was detected in most samples (n=100), some alternatives, namely bisphenol S (BPS), Pergafast® 201 and D-8 have been found in 4, 11 and 9 samples respectively. As no or few data on their endocrine activity are available, these chemicals and bisphenol F (BPF) were tested in vitro using the H295R steroidogenesis assay. 17β-Estradiol production was induced by BPA and BPF, whereas free testosterone production was inhibited by BPA and BPS. Both non-bisphenol substances did not show significant effects. The binding affinity to 16 proteins and the toxicological potential (TP) were further calculated in silico using VirtualToxLab™. TP values lay between 0.269 and 0.476 and the main target was the estrogen receptor β (84.4 nM to 1.33 μM). A substitution of BPA by BPF and BPS should be thus considered with caution, since they exhibit almost a similar endocrine activity as BPA. D-8 and Pergafast® 201 could be alternatives to replace BPA, however further analyses are needed to better characterize their effects on the hormonal system.

title: A new chapter in the bisphenol A story: bisphenol S and bisphenol F are not safe alternatives to this compound.
abstract: Bisphenol A (BPA) is a widely studied typical endocrine-disrupting chemical, and one of the major new issues is the safe replacement of this commonly used compound. Bisphenol S (BPS) and bisphenol F (BPF) are already or are planned to be used as BPA alternatives. With the use of a culture system that we developed (fetal testis assay [FeTA]), we previously showed that 10 nmol/L BPA reduces basal testosterone secretion of human fetal testis explants and that the susceptibility to BPA is at least 100-fold lower in rat and mouse fetal testes. Here, we show that addition of LH in the FeTA system considerably enhances BPA minimum effective concentration in mouse and human but not in rat fetal testes. Then, using the FeTA system without LH (the experimental conditions in which mouse and human fetal testes are most sensitive to BPA), we found that, as for BPA, 10 nmol/L BPS or BPF is sufficient to decrease basal testosterone secretion by human fetal testes with often nonmonotonic dose-response curves. In fetal mouse testes, the dose-response curves were mostly monotonic and the minimum effective concentrations were 1,000 nmol/L for BPA and BPF and 100 nmol/L for BPS. Finally, 10,000 nmol/L BPA, BPS, or BPF reduced Insl3 expression in cultured mouse fetal testes. This is the first report describing BPS and BPF adverse effects on a physiologic function in humans and rodents.

title: Effects of exposure to BPF on development and sexual differentiation during early life stages of zebrafish (Danio rerio).
abstract: Bisphenol F (BPF) has become a predominant bisphenol contaminant in recent years. It has significant estrogenic properties in both in vivo and in vitro studies. We have previously studied the disrupting mechanisms of BPF on the hypothalamic-pituitary-gonadal axis of adult zebrafish. However, the effects of BPF exposure on development and sexual differentiation of zebrafish embryos/larvae remain unclear. To determine the effects of BPF on the critical stage of sex differentiation in zebrafish, zebrafish embryos/larvae were exposed to 1, 10, 100, and 1000 μg/L BPF from fertilization to 60 days post-fertilization (dpf). Developmental malformations were induced by exposure to BPF from 2 h post-fertilization (hpf), with a LC50 of 10,030 μg/L at 96 hpf and 9391 μg/L at 120 hpf. Long-term exposure during sex differentiation tended to result in a female sex ratio bias. Histological analyses at 60 dpf indicated that the development of ovo-testes and immature ovaries was induced by 100 and 1000 μg/L BPF. Homogenate testosterone levels decreased and 17β-estradiol levels increased in zebrafish in a concentration-dependent manner. BPF exposure suppressed gene expression of double sex, Mab3-related transcription factor 1(dmrt1), fushi tarazu factor 1d (ff1d), sry-box containing gene 9a (sox9a) and anti-Mullerian hormone (amh); induced expression of the forkhead box L2 transcription factor (foxl2), leading to increased expression of aromatase (cyp19a1a), which promoted production of estrogens, and further caused phenotypic feminization of zebrafish. These results suggest that developmental exposure to BPF has adverse effects on sexual differentiation, and the results were useful for a BPF risk assessment.

title: Embryonic stem cell- and transcriptomics-based in vitro analyses reveal that bisphenols A, F and S have similar and very complex potential developmental toxicities.
abstract: Bisphenol A (BPA) is a very versatile industrial chemical. Many reports have associated BPA with several health effects. Some bisphenol alternatives have been introduced to replace BPA in its many applications. However, comprehensive toxicological evaluations for these replacements are still lacking. In this study, we examined the potential effects of BPA, bisphenol F (BPF) and bisphenol S (BPS), on embryonic development with an in vitro stem cell toxicology system and transcriptomics analyses. Mouse embryonic stem cells (mESCs) were differentiated via embryoid body formation, either globally towards the three primary germ layers and their lineages, or specifically into neuroectoderm/neural progenitor cells. During the differentiation, cells were treated with BPA, BPF, BPS, or DMSO control. Samples were collected at different time points, for qRT-PCR and RNA-seq analyses. BPA, BPF and BPS disrupted many processes, during mESC global and neural differentiations, in very similar manners. In fact, at each time point the three chemicals differentially regulated analogous gene categories, particularly the ones involved in cell-matrix and cell-cell adhesion, signal transduction pathways, and medical conditions such as cardiovascular diseases and cancer. Our findings demonstrate once more then BPA substitutes may not be very safe. They potentially have a very complex developmental toxicity, similarly to BPA, and seem more toxic than BPA itself. In addition, our results reveal that stem cell-based developmental toxicity assays can be very comprehensive.

title: Differential responses of GC‑1 spermatogonia cells to high and low doses of bisphenol A.
abstract: Bisphenol A (BPA) is an environmental endocrine disruptor. The exact effect of BPA on spermatogenesis and the specific epigenetic effects on mouse spermatogonia remain to be elucidated. The present study exposed the GC‑1 spermatogonial cell line to a series of differing BPA concentrations and examined the subsequent effects on cell proliferation, mitogen activated protein kinase (MAPK) signaling, DNA and histone methylation. A Cell Counting Kit‑8 assay revealed that BPA significantly inhibited cell growth at the concentration of 10 µg/ml, however no significant alterations were detected at lower BPA doses. The global DNA methylation levels were reduced at the dose of 10 µg/ml of BPA, via detection of 5‑methylcytosine using a dot blot. The protein and mRNA expression levels of DNA methyltransferase (DNMT) 1 were decreased at 10 and 1 µg/ml of BPA, detected via western blotting and reverse transcription‑quantitative polymerase chain reaction, respectively. The global levels of H3K27me3 was decreased at 10 µg/ml BPA, detected via western blotting. Increased phosphorylation of p38 and decreased phosphorylation of extracellular signal‑regulated kinases 1/2 were observed at 10 and 1 µg/ml BPA. The results demonstrated that high and low doses of BPA exposure exhibit differential effects on cell growth, global DNA methylation, histone H3K9Me3 and H3K27Me3 levels and additionally affect the MAPK signaling pathways.

title: Bisphenol A (BPA) and bisphenol S (BPS) alter the promoter activity of the ABCB1 gene encoding P‐glycoprotein in the human placenta in a haplotype‐dependent manner
abstract: Exposure to bisphenols (BPA and BPS) during pregnancy can significantly affect fetal development and increase risk of adverse health consequences, however the underlying mechanisms are not fully elucidated. In human placenta, the efflux transporter P‐glycoprotein (P‐gp), encoded by the ABCB1 gene, extrudes its substrates from the trophoblasts back into the maternal circulation. Alterations in levels of placental P‐gp could therefore significantly affect fetal exposure to xenobiotics that are P‐gp substrates. The ABCB1 promoter contains many single nucleotide polymorphisms (SNPs). In the genome, SNPs are not arrayed as independent variants but as combinations forming defined haplotypes. Recently, we determined the haplotype sequences encompassing the ABCB1 promoter SNPs and found that promoter haplotypes differentially affect ABCB1 promoter activity. Here we investigate the effect of BPA and BPS on ABCB1 promoter activity by testing the hypothesis that BPA and BPS exposure affect ABCB1 promoter activity in a haplotype‐dependent manner. Our data indicate that acute exposure to 50nM BPA induced a significant haplotype‐dependent increase in ABCB1 promoter activity (P<.05). However, acute exposure to 0.5nM BPS induced a significant decrease (P<.05) in promoter activity that was haplotype‐dependent. Chronic exposure to BPA and BPS individually (5nM and 0.3nM, respectively) or as a mixture (5nM BPA:1.5nM BPS) induced significant haplotype‐dependent increases (P<.01) in ABCB1 promoter activity. Our data indicate that BPA and BPS significantly alter ABCB1 promoter activity in a haplotype‐ and exposure type‐ dependent manners. Such alteration could significantly impact placental P‐gp levels and alter fetal exposure to many therapeutic and environmental xenobiotics. HIGHLIGHTSBPA and BPS alter ABCB1 promoter activity in a haplotype‐dependent manner.Acute BPA exposure elicits haplotype‐dependent increases in ABCB1 promoter activity.Acute BPS exposure elicits haplotype‐dependent decreases in ABCB1 promoter activity.Chronic exposure to BPA/BPS elicits haplotype‐dependent increases in ABCB1 activity.Alteration of ABCB1 promoter activity could significantly affect P‐gp levels.

title: Bisphenol A interferes with thyroid specific gene expression.
abstract: Bisphenol A (BPA) is an endocrine-disrupting chemical that leads to low-dose human exposure due to its ability to leach from chemically derived products, as polycarbonate plastics and epoxy resin. In addition to its known xeno-endocrine action, BPA exerts a wide range of metabolic effects. Despite the documented BPA exposure outcomes on synthesis of thyroid hormones, there are not any data available on its actions on the thyroid follicular cells, site of synthesis of the thyroid hormones. Recently, it has been shown that several environmental pollutants, as BPA, can exert a thyroid disrupting activity. In this study, we employed in vitro and in vivo (zebrafish) models to examine the effects of BPA in regulating the expression of genes involved in the thyroid hormone synthesis and of their transcriptional regulators at BPA doses as low as 10(-9)M, a dose that is environmentally pertinent and far below the one detected in infants plasma. In both systems we could detect an altered expression of the genes involved in thyroid hormones synthesis and of thyroid specific transcriptional factors in BPA dose and time dependent manner. Our results suggest that BPA exerts a direct effect on thyroid follicular cell. We show that these cells can "sense" very low amount of BPA. Thus they, potentially, represent an ideal in vitro system to develop assays to detect BPA and other pollutants with thyroid disrupting activity at level far below the ones considered to be environmental relevant. Moreover, this report may provide new insight into the mode of BPA-induced deregulation of physiological processes as well as on the extensively debated molecular pathways underlying its biological activities.

title: Low concentrations of bisphenol a suppress thyroid hormone receptor transcription through a nongenomic mechanism.
abstract: Bisphenol (BPA) is one of the highest-volume chemicals produced worldwide, and human exposure to BPA is thought to be ubiquitous. Various rodent and in vitro studies have shown that thyroid hormone (TH) function can be impaired by BPA. However, it is still unknown if low concentrations of BPA can suppress the thyroid hormone receptor (TR) transcription. The present study aims to investigate the possible suppressing effects of low concentrations of BPA on TR transcription and the involved mechanism(s) in CV-1 cells derived from cercopithecus aethiops monkey kidneys. Using gene reporter assays, BPA at concentrations as low as 10(-9)M suppresses TR or steroid receptor coactivator-1(SRC-1)-enhanced TR transcription, but not reducing TR/SRC-1 interaction in mammalian two-hybrid and glutathione S-transferase pull-down studies. It has been further shown that both nuclear receptor co-repressor (N-CoR) and silencing mediator for retinoid and thyroid hormone receptors (SMRT) are recruited to the TR-β1 by BPA in the presence of physiologic concentrations of T3 or T4. However, the overexpression of β3 integrin or c-Src significantly reduces BPA-induced recruitment of N-CoR/SMRT to TR or suppression of TR transcription. Furthermore, BPA inhibits the T3/T4-mediated interassociation of the β3 integrin/c-Src/MAPK/TR-β1 pathways by the co-immunoprecipitation. These results indicate that low concentrations of BPA suppress the TR transcription by disrupting physiologic concentrations of T3/T4-mediated β3 integrin/c-Src/MAPK/TR-β1 pathways, followed by recruiting N-CoR/SMRT to TR-β1, providing a novel insight regarding the TH disruption effects of low concentration BPA.

title: Embryonic Exposure to Bisphenol A Impairs Primordial Germ Cell Migration without Jeopardizing Male Breeding Capacity
abstract: A large amount of chemicals are released to the environment each year. Among them, bisphenol A (BPA) is of utmost concern since it interferes with the reproductive system of wild organisms due to its capacity to bind to hormone receptors. Additionally, BPA epigenotoxic activity is known to affect basic processes during embryonic life. However, its effects on primordial germ cells (PGCs) proliferation and migration, both mechanisms being crucial for gametogenesis, remain unknown. To investigate the effects of BPA on PGCs migration and eventual testicle development, zebrafish embryos were exposed to 100, 2000 and 4000 µg/L BPA during the first 24 h of development. Vasa immunostaining of PGCs revealed that exposure to 2000 and 4000 µg/L BPA impaired their migration to the genital ridge. Two pivotal genes of PGCs migration (cxcr4b and sdf1a) were highly dysregulated in embryos exposed to these doses, whereas DNA methylation and epigenetic marks in PGCs and their surrounding somatic cells were not altered. Once embryos reached adulthood, the morphometric study of their gonads revealed that, despite the reduced number of PGCs which colonized the genital ridges, normal testicles were developed. Although H3K9ac decreased in the sperm from treated fishes, it did not affect the progeny development.

title: Urinary bisphenol A (BPA) concentration associates with obesity and insulin resistance.
abstract: Bisphenol A (BPA) is one of the world's highest-volume chemicals in use today. Previous studies have suggested BPA disturbs body weight regulation and promotes obesity and insulin resistance. But epidemiological data in humans were limited.



Our objective was to determine whether BPA associates with obesity and insulin resistance.



This cross-sectional study included 3390 adults aged 40 yr or older, in Songnan Community, Baoshan District, Shanghai, China.



Questionnaire, clinical and biochemical measurements, and urinary BPA concentration were determined. Generalized overweight was defined as body mass index (BMI) of 24 to less than 28 kg/m(2) and obesity was defined as BMI of 28 kg/m(2) or higher. Abdominal obesity was defined as waist circumference at least 90 cm for men and at least 85 cm for women. Insulin resistance was defined as the index of homeostasis model assessment of insulin resistance higher than 2.50.



The participants in the highest quartile of BPA had the highest prevalence of generalized obesity [odds ratio (OR) = 1.50; 95% confidence interval (CI) = 1.15-1.97], abdominal obesity (OR = 1.28; 95% CI = 1.03-1.60), and insulin resistance (OR = 1.37; 95% CI = 1.06-1.77). In participants with BMI under 24 kg/m(2), compared with the lowest quartile, the highest quartile of BPA increased the prevalence of insulin resistance by 94% (OR = 1.94; 95% CI = 1.20-3.14), but this association was not observed in those with BMI of 24 kg/m(2) or higher.



BPA was positively associated with generalized obesity, abdominal obesity, and insulin resistance in middle-aged and elderly Chinese adults.

title: Association between urinary bisphenol A concentration and obesity prevalence in children and adolescents.
abstract: Bisphenol A (BPA), a manufactured chemical, is found in canned food, polycarbonate-bottled liquids, and other consumer products. In adults, elevated urinary BPA concentrations are associated with obesity and incident coronary artery disease. BPA exposure is plausibly linked to childhood obesity, but evidence is lacking to date.



To examine associations between urinary BPA concentration and body mass outcomes in children.



Cross-sectional analysis of a nationally representative subsample of 2838 participants aged 6 through 19 years randomly selected for measurement of urinary BPA concentration in the 2003-2008 National Health and Nutrition 
Body mass index (BMI), converted to sex- and age-standardized z scores and used to classify participants as overweight (BMI ≥85th percentile for age/sex) or obese (BMI ≥95th percentile).



Median urinary BPA concentration was 2.8 ng/mL (interquartile range, 1.5-5.6). Of the participants, 1047 (34.1% [SE, 1.5%]) were overweight and 590 (17.8% [SE, 1.3%]) were obese. Controlling for race/ethnicity, age, caregiver education, poverty to income ratio, sex, serum cotinine level, caloric intake, television watching, and urinary creatinine level, children in the lowest urinary BPA quartile had a lower estimated prevalence of obesity (10.3% [95% CI, 7.5%-13.1%]) than those in quartiles 2 (20.1% [95% CI, 14.5%-25.6%]), 3 (19.0% [95% CI, 13.7%-24.2%]), and 4 (22.3% [95% CI, 16.6%-27.9%]). Similar patterns of association were found in multivariable analyses examining the association between quartiled urinary BPA concentration and BMI z score and in analyses that examined the logarithm of urinary BPA concentration and the prevalence of obesity. Obesity was not associated with exposure to other environmental phenols commonly used in other consumer products, such as sunscreens and soaps. In stratified analysis, significant associations between urinary BPA concentrations and obesity were found among whites (P < .001) but not among blacks or Hispanics.



Urinary BPA concentration was significantly associated with obesity in this cross-sectional study of children and adolescents. Explanations of the association cannot rule out the possibility that obese children ingest food with higher BPA content or have greater adipose stores of BPA.

title: Bisphenol S exposure impairs glucose homeostasis in male zebrafish (Danio rerio).
abstract: Bisphenol S (BPS) is a substitute of the plastic additive bisphenol A (BPA). Its concentrations detected in surface waters and urine samples are on the same order of magnitude as BPA. Human exposure to BPA has been implicated in the development of diabetes mellitus; however, whether BPS can disrupt glucose homeostasis and increase blood glucose concentration remains unclear. We extensively investigated the effects of environmentally relevant concentrations of BPS on glucose metabolism in male zebrafish (Danio rerio) and the underlying mechanisms of these effects. Male zebrafish were exposed to 1, 10, or 100μg/L of BPS for 28 d. Fasting blood glucose (FBG) levels, glycogen levels in the liver and muscle, and mRNA levels of key glucose metabolic enzymes and the activities of the encoded proteins in tissues were evaluated to assess the effect of BPS on glucose metabolism. Plasma insulin levels and expression of preproinsulin and glucagon genes in the visceral tissue were also evaluated. Compared with the control group, exposure to 1 and 10μg/L of BPS significantly increased FBG levels but decreased insulin levels. Gluconeogenesis and glycogenolysis in the liver were promoted, and glycogen synthesis in the liver and muscle and glycolysis in the muscle were inhibited. Exposure to 100μg/L of BPS did not significantly alter plasma insulin and blood glucose levels, but nonetheless pronouncedly interfered with gluconeogenesis, glycogenolysis, glycolysis, and glycogen synthesis. Our data indicates that BPS at environmentally relevant concentrations impairs glucose homeostasis of male zebrafish possibly by hampering the physiological effect of insulin; higher BPS doses also pronouncedly interfered with glucose metabolism.

title: Urine Bisphenol-A Level in Relation to Obesity and Overweight in School-Age Children
abstract: Bisphenol-A (BPA) is a potential endocrine disruptor impacting metabolic processes and increasing the risk of obesity. To determine whether urine BPA level is associated with overweight/obesity in school-age children, we examined 1,326 students in grades 4–12 from three schools (one elementary, one middle, and one high school) in Shanghai. More than 98% of eligible students participated. Total urine BPA concentration was measured and anthropometric measures were taken by trained research staff. Information on risk factors for childhood obesity was collected for potential confounders. Age- and gender-specific weight greater than 90th percentile of the underlying population was the outcome measure. After adjustment for potential confounders, a higher urine BPA level (≥2 µg/L), at the level corresponding to the median urine BPA level in the U.S. population, was associated with more than two-fold increased risk of having weight >90th percentile among girls aged 9–12 (adjusted odds ratio (aOR) = 2.32, 95% confidence interval: 1.15–4.65). The association showed a dose-response relationship with increasing urine BPA level associated with further increased risk of overweight (p = 0.006 for trend test). Other anthropometric measures of obesity showed similar results. The same association was not observed among boys. This gender difference of BPA effect was consistent with findings from experimental studies and previous epidemiological studies. Our study suggests that BPA could be a potential new environmental obesogen. Widespread exposure to BPA in the human population may also be contributing to the worldwide obesity epidemic.

title: Systematic Review and Meta-Analysis of Early-Life Exposure to Bisphenol A and Obesity-Related Outcomes in Rodents
abstract: Early-life exposure to bisphenol A (BPA) has been implicated to play a role in the development of obesity.  A systematic review with meta-analyses of experimental rodent studies was conducted to answer the following question: does early-life exposure to BPA affect the obesity-related outcomes body weight, fat (pad) weight, and circulating and tissue levels of triglycerides, free fatty acids (FFA), and leptin?  The methodology was prespecified in a rigorous protocol using the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) approach. Using PubMed and EMBASE, we identified 61 articles that met the inclusion criteria. The risk of bias and the methodological quality of these articles were assessed using the SYRCLE Risk of Bias tool, and a confidence-rating methodology was used to score the quality of evidence. Meta-analyses were performed using random effect models and standardized mean differences (SMDs), or, where possible, mean differences (MDs) were calculated.  Overall summary estimates indicated significant positive associations between BPA and fat weight [SMD=0.67 (95% CI: 0.53, 0.81)], triglycerides [SMD=0.97 (95% CI: 0.53, 1.40)], and FFA [SMD=0.86 (95% CI: 0.50, 1.22)], and a nonsignificant positive association with leptin levels [MD=0.37 (95% CI: −0.14, 0.87)] and a significant negative association with body weight were estimated [MD=−0.22 (95% CI: −0.37, −0.06)]. Subgroup analyses revealed stronger positive associations for most outcome measures in males and at doses below the current U.S. reference dose of 50μg/kg/d compared with doses above the reference dose. It should be noted that there was substantial heterogeneity across studies for all outcomes assessed and that there was insufficient information to assess risk of bias for most studies.  Findings from our systematic review suggest that early-life exposure to BPA may increase adiposity and circulating lipid levels in rodents. https://doi.org/10.1289/EHP1233

title: Endocrine Disruptors Leading to Obesity and Related Diseases
abstract: The review aims to comprehensively present the impact of exposure to endocrine disruptors (EDs) in relation to the clinical manifestation of obesity and related diseases, including diabetes mellitus, metabolic syndrome, cardiovascular diseases, carcinogenesis and infertility. EDs are strong participants in the obesity epidemic scenery by interfering with cellular morphological and biochemical processes; by inducing inflammatory responses; and by presenting transcriptional and oncogenic activity. Obesity and lipotoxicity enhancement occur through reprogramming and/or remodeling of germline epigenome by exposure to EDs. Specific population groups are vulnerable to ED exposure due to current dietary and environmental conditions. Obesity, morbidity and carcinogenicity induced by ED exposure are an evolving reality. Therefore, a new collective strategic approach is deemed essential, for the reappraisal of current global conditions pertaining to energy management.

title: Urinary bisphenol A concentration and glucose homeostasis in non-diabetic adults: a repeated-measures, longitudinal study
abstract: A (BPA) has been shown to be potentially associated with type 2 diabetes; however, there is little evidence associating BPA exposure with glucose metabolic outcomes prior to diabetes onset. We aimed to examine BPA exposure in relation to glucose homeostasis among non-diabetic individuals.MethodsThis longitudinal cohort study comprised 2336 Chinese adults aged 40 years or above (62.8% women) and free of diabetes at baseline in 2009, followed for 4 years. Urinary BPA and glucose metabolic traits including fasting plasma glucose (FPG), 2 h post-load plasma glucose, fasting serum insulin, HOMA-IR and HOMA-B were measured at baseline and follow-up. Repeated-measures analysis was performed to evaluate associations of urinary BPA concentration with markers of glucose homeostasis.ResultsAfter full adjustment for confounders including BMI, each tenfold increase in urinary BPA concentrations was associated with a 3.39% increase in FPG (95% CI 2.24%, 4.55%) and an 11.6% decrease in HOMA-B (95% CI −15.8%, −7.18%) in women. The inverse association between urinary BPA and HOMA-B was more prominent among overweight or obese individuals (change −13.7%; 95% CI −19.3%, −7.61%) compared with those who were of normal weight (change −6.74%; 95% CI −13.2%, 0.20%) (pinteraction = 0.07). Moreover, the ORs of fasting hyperglycaemia and beta cell dysfunction corresponding to a tenfold increase in urinary BPA concentrations were 1.37 (95% CI 1.10, 1.72) and 1.30 (95% CI 1.02, 1.65) in women, respectively. No significant associations existed between urinary BPA and glucose metabolic markers in men.Conclusions/interpretationOur findings suggest that exposure to BPA was independently associated with impaired glucose homeostasis before the development of diabetes in middle-aged and elderly women.

title: Inhibition of Type 1 Iodothyronine Deiodinase by Bisphenol A.
abstract: Plastics are ubiquitously present in our daily life and some components of plastics are endocrine-disrupting chemicals, such as bisphenol A and phthalates. Herein, we aimed to evaluate the effect of plastic endocrine disruptors on type 1 and type 2 deiodinase activities, enzymes responsible for the conversion of the pro-hormone T4 into the biologically active thyroid hormone T3, both in vitro and in vivo. Initially, we incubated rat liver type 1 deiodinase and brown adipose tissue type 2 deiodinase samples with 0.5 mM of the plasticizers, and the deiodinase activity was measured. Among them, only BPA was capable to inhibit both type 1 and type 2 deiodinases. Then, adult male Wistar rats were treated orally with bisphenol A (40 mg/kg b.w.) for 15 days and hepatic type 1 deiodinase and brown adipose tissue type 2 deiodinase activities and serum thyroid hormone concentrations were measured. In vivo bisphenol A treatment significantly reduced hepatic type 1 deiodinase activity but did not affect brown adipose tissue type 2 deiodinase activity. Serum T4 levels were higher in bisphenol A group, while T3 remained unchanged. T3/T4 ratio was decreased in rats treated with bisphenol A, reinforcing the idea that peripheral metabolism of thyroid hormone was affected by bisphenol A exposure. Therefore, our results suggest that bisphenol A can affect the metabolism of thyroid hormone thus disrupting thyroid signaling.

title: Bisphenol A is related to circulating levels of adiponectin, leptin and ghrelin, but not to fat mass or fat distribution in humans.
abstract: Since bisphenol A (BPA) has been shown to induce obesity in experimental studies, we explored the associations between BPA and fat mass, fat distribution and circulating levels of adiponectin, leptin and ghrelin in humans.



In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS), fat mass and fat distribution were determined in 70-year-old men and women (n=890) by dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI) (n=287). Serum levels of BPA were analyzed using isotope liquid chromatography/tandem mass spectrometer (API4000LC-MS/MS). Hormone levels were analyzed with radioimmunoassays (RIA) or enzyme-linked immunosorbent assay (ELISA). Imaging was performed approximately two years following collection of other data.



Serum concentrations of BPA were not related to adipose tissue measurements by DXA or MRI. BPA associated positively with adiponectin and leptin, but negatively with ghrelin, following adjustments for sex, height, fat mass, lean mass, smoking, alcohol consumption, physical activity, energy intake, and educational levels (p<0.001, p=0.009, p<0.001, respectively). The relationship between BPA and ghrelin was stronger in women than in men.



Although no relationships between BPA levels and measures of fat mass were seen, BPA associated strongly with the adipokines adiponectin and leptin and with the gut-hormone ghrelin suggesting that BPA may interfere with hormonal control of hunger and satiety.

title: Association between bisphenol A exposure and body mass index in Chinese school children: a cross-sectional study
abstract: BackgroundThere is increasing evidence suggesting that Bisphenol A (BPA), one of the highest volume chemicals produced worldwide, can interfere with the body’s natural weight control mechanisms to promote obesity. However, epidemiological studies for this are limited, especially for children.MethodsA cross-sectional study was conducted to investigate the association between BPA exposure and body mass index (BMI) in school children. Three primary and three middle schools were randomly selected from 26 primary and 30 middle candidate schools in Changning District of Shanghai City in China. According to the BMI-based criteria by age and sex for screening of overweight or obese children, we randomly chose 20 obese, 10 overweight, and 30 normal weight children aged 8-15 years of age from each selected school. First morning urine was collected and total urine BPA concentrations were determined by ultra-performance liquid chromatography tandem mass spectrometry. Multiple linear regression analysis was conducted to examine the association of urine BPA concentrations and daily intake estimates with BMI.ResultsBPA was detected in 84.9% of urine samples with a geometric mean of 0.45 ng/mL. The daily intake estimates ranged from 0.03 μg/day to 1.96 μg/day with a geometric mean of 0.37 μg/day. The average urine BPA concentrations and daily intake estimates were similar for boys and girls, but significantly higher in older children than younger ones, and showed an increasing trend with BMI. Multiple linear regression analyses showed that urine BPA concentrations were significantly associated with increasing BMI values in all subjects after adjustment for age and sex and the results were similar before and after corrected by urine specific gravity. When stratified by age or sex, the associations remained significant in females and in those 8-11 years of age before corrected by specific gravity. Similar results were shown for the association between BMI and daily intake estimates.ConclusionsThere is a possibility that BPA exposure increases BMI in school children. Given the cross-sectional nature of this study, longitudinal studies are warranted to confirm BPA exposure as a contributor to increased BMI in children.

title: Association of urinary concentrations of bisphenols with type 2 diabetes mellitus: A case-control study.
abstract: Bisphenols, as synthetic chemicals, have been widely detected in environmental and human samples. Epidemiological studies have reported relationships between bisphenol A (BPA) and type 2 diabetes mellitus (T2DM), but results are inconsistent. Additionally, the associations between other bisphenols (i.e., the substitutes of BPA) with T2DM have been scarcely reported. A case-control study was conducted to examine the associations of urinary bisphenols with T2DM by investigating 8 bisphenols in urine samples of 251 T2DM cases and 251 controls and using different statistic models. Urinary bisphenol AF (BPAF) and bisphenol S (BPS) concentrations were significantly positively associated with T2DM in the log-transformed statistical models and adjusted odd ratios (ORs) were separately 4.95 [95% confidence interval (CI): 3.15, 7.79] and 1.73 (95% CI: 1.37, 2.18), which was consistent with the results in categorical models (OR = 2.03; 95% CI: 1.31, 3.15; p = 0.001 for BPAF; OR = 3.83; 95% CI: 2.37, 6.20; p < 0.001 for BPS). In addition, in the categorical models, elevated odds of T2DM were observed in the second BPA quartile (OR = 2.58; 95% CI: 1.38, 4.80) and the third quartile (OR = 1.89; 95% CI: 1.03, 3.46), but not in the fourth quartile, which reflected a nonlinear association between urinary BPA and T2DM. Similarly, only significant positive association with T2DM was found in the second quartile of the sum of bisphenols (OR = 2.07; 95% CI: 1.12, 3.82). In the sensitivity analyses, the associations of bisphenols with T2DM remained consistent except for BPAF in the categorical model. Our study suggested that several urinary bisphenols were positively associated with T2DM.

title: Bisphenol A exposure and type 2 diabetes mellitus risk: a meta-analysis
abstract: BackgroundThis meta-analytic study explored the relationship between the risk of type 2 diabetes mellitus (T2DM) and bisphenol A concentrations.MethodsThe Embase and Medline (PubMed) databases were searched, using relevant keywords, for studies published between 1980 and 2018. A total of 16 studies, twelve cross-sectional, two case-control and one prospective, were included in the meta-analysis. The odds ratio (OR) and its 95% confidence interval (CI) were determined across the sixteen studies. The OR and its 95% CI of diabetes associated with bisphenol A were estimated using both fixed-effects and random-effects models. total of 41,320 subjects were included. Fourteen of the sixteen studies included in the analysis provided measurements of urine bisphenol A levels and two study provided serum bisphenol A levels. Bisphenol A concentrations in human bio-specimens showed positive associations with T2DM risk (OR 1.28, 95% CI 1.14, 1.44). A sensitivity analysis indicated that urine bisphenol A concentrations were positively associated with T2DM risk (OR 1.20, 95% CI 1.09, 1.31).ConclusionsThis meta-analysis indicated that Bisphenol A exposure is positively associated with T2DM risk in humans.

title: Relationship between urinary bisphenol A levels and diabetes mellitus.
abstract: Bisphenol A (BPA) is a widely used chemical in the manufacture of polycarbonate plastics and epoxy resins. Recent animal studies have suggested that BPA exposure may have a role in the development of weight gain, insulin resistance, pancreatic endocrine dysfunction, thyroid hormone disruption, and several other mechanisms involved in the development of diabetes. However, few human studies have examined the association between markers of BPA exposure and diabetes mellitus.



We examined the association between urinary BPA levels and diabetes mellitus in the National Health and Nutritional Examination Survey (NHANES) 2003-2008. Urinary BPA levels were examined in quartiles. The main outcome of interest was diabetes mellitus defined according the latest American Diabetes Association guidelines.



Overall, we observed a positive association between increasing levels of urinary BPA and diabetes mellitus, independent of confounding factors such as age, gender, race/ethnicity, body mass index, and serum cholesterol levels. Compared to quartile 1 (referent), the multivariate-adjusted odds ratio (95% confidence interval) of diabetes associated with quartile 4 was 1.68 (1.22-2.30) (p-trend = 0.002). The association was present among normal-weight as well as overweight and obese subjects.



Urinary BPA levels are found to be associated with diabetes mellitus independent of traditional diabetes risk factors. Future prospective studies are needed to confirm or disprove this finding.

title: Long-term bisphenol A exposure accelerates insulitis development in diabetes-prone NOD mice
abstract: Exposure to the endocrine disruptor (ED) bisphenol A (BPA) used in polycarbonate plastic and epoxy resins appears ubiquitous since BPA can be found in over 90% of analyzed urine samples from all age groups. There is a parallel occurrence of increased prevalence in type 1 diabetes mellitus (T1DM) and an increased exposure to EDs the last decades. T1DM is caused by insulin deficiency due to autoimmune destruction of insulin producing pancreatic beta cells and has been suggested to be induced by various environmental factors acting together with a genetic predisposition. The objective of the present study was to investigate the effect of BPA (0, 1 and 100 mg/l BPA in the drinking water) on T1DM development in nonobese diabetic (NOD) mice, spontaneously developing T1DM. Histological evaluation of pancreas from 12-weeks-old female mice revealed significantly increased insulitis in mice exposed to 1 mg/l BPA, while the insulitis was less severe at the higher BPA exposure. Serum glucose levels in the 1 mg/ml BPA group tended to be hyperglycaemic, also indicating an accelerated onset of T1DM. The high BPA exposure seemed to counteract the diabetes development in females and also in male NOD mice for both BPA concentrations. Prior to insulitis, both BPA concentrations resulted in increased apoptosis and reduced numbers of tissue resident macrophages in pancreatic islets. In conclusion, long-term BPA exposure at a dose three times higher than the tolerable daily intake of 50 µg/kg, appeared to accelerate spontaneous insulitis and diabetes development in NOD mice.

title: Perinatal Bisphenol A Exposure and Adult Glucose Homeostasis: Identifying Critical Windows of Exposure
abstract: Bisphenol A (BPA) is a widespread endocrine-disrupting chemical used as the building block for polycarbonate plastics. Epidemiological evidence has correlated BPA exposure with higher risk of heart disease and type 2 diabetes. However, it remains unknown whether there are critical windows of susceptibility to BPA exposure on the development of dysglycemia. This study was an attempt to investigate the critical windows and the long-term consequences of perinatal exposure to BPA on glucose homeostasis. Pregnant mice were given either vehicle or BPA (100 µg/kg/day) at different time of perinatal stage: 1) on days 1–6 of pregnancy (P1–P6, preimplantation exposure); 2) from day 6 of pregnancy until postnatal day (PND) 0 (P6–PND0, fetal exposure); 3) from lactation until weaning (PND0–PND21, neonatal exposure); and 4) from day 6 of gestation until weaning (P6–PND21, fetal and neonatal exposure). At 3, 6 and 8 months of age, offspring in each group were challenged with glucose and insulin tolerance tests. Then islet morphometry and β-cell function were measured. The glucose homeostasis was impaired in P6-PND0 mice from 3 to 6 months of age, and this continued to 8 months in males, but not females. While in PND0-PND21 and P6-PND21 BPA-treated groups, only the 3-month-old male offspring developed glucose intolerance. Moreover, at the age of 3 months, perinatal exposure to BPA resulted in the increase of β-cell mass mainly due to the coordinate changes in cell replication, neogenesis, and apoptosis. The alterations of insulin secretion and insulin sensitivity, rather than β-cell mass, were consistent with the development of glucose intolerance. Our findings suggest that BPA may contribute to metabolic disorders relevant to glucose homeostasis and the effects of BPA were dose, sex, and time-dependent. Fetal development stage may be the critical window of susceptibility to BPA exposure.

title: Urinary Bisphenol A and Hypertension in a Multiethnic Sample of US Adults
abstract: Bisphenol A (BPA) is a common chemical used in the manufacture of polycarbonate plastics and epoxy resins, with >93% of US adults having detectable BPA levels in urine. Recent animal studies have suggested that BPA exposure may have a role in several mechanisms involved in the development of hypertension, including weight gain, insulin resistance, thyroid dysfunction, endothelial dysfunction, and oxidative stress. However, no previous human study has examined the association between markers of BPA exposure and hypertension.  We examined urinary BPA levels in 1380 subjects from the National Health and Nutritional Examination Survey 2003-2004. Main outcome-of-interest was hypertension, defined as blood pressure-reducing medication use and/or blood pressures >140/90 mm of Hg (n = 580).  We observed a positive association between increasing levels of urinary BPA and hypertension independent of confounding factors such as age, gender, race/ethnicity, smoking, body mass index (BMI), diabetes mellitus and total serum cholesterol levels. Compared to tertile 1 (referent), the multivariate-adjusted odds ratio (95% confidence interval) of hypertension associated with tertile 3 was 1.50 (1.12−2.00); P-trend = 0.007. The association was consistently present in subgroup analyses by race/ethnicity, smoking status, BMI, and diabetes mellitus.  Urinary BPA levels are associated with hypertension, independent of traditional risk factors.

title: Bisphenol A and Peripheral Arterial Disease: Results from the NHANES
abstract: Bisphenol A (BPA) is a common chemical used in the manufacture of polycarbonate plastics and epoxy resins, and > 93% of U.S. adults have detectable levels of urinary BPA. Recent animal studies have suggested that BPA exposure may have a role in several mechanisms involved in the development of cardiovascular disease (CVD), including weight gain, insulin resistance, thyroid dysfunction, endothelial dysfunction, and oxidative stress. However, few human studies have examined the association between markers of BPA exposure and CVD. Peripheral arterial disease (PAD) is a subclinical measure of atherosclerotic vascular disease and a strong independent risk factor for CVD and mortality.  We examined the association between urinary BPA levels and PAD in a nationally representative sample of U.S. adults.  We analyzed data from 745 participants in the National Health and Nutritional Examination Survey 2003–2004. We estimated associations between urinary BPA levels (in tertiles) and PAD (ankle–brachial index < 0.9, n = 63) using logistic regression models adjusted for potential confounders (age, sex, race/ethnicity, education, smoking, body mass index, diabetes mellitus, hypertension, urinary creatinine, estimated glomerular filtration rate, and serum cholesterol levels).  We observed a significant, positive association between increasing levels of urinary BPA and PAD before and after adjusting for confounders. The multivariable-adjusted odds ratio for PAD associated with the highest versus lowest tertile of urinary BPA was 2.69 (95% confidence interval: 1.02, 7.09; p-trend = 0.01).  Urinary BPA levels were significantly associated with PAD, independent of traditional CVD risk factors.

title: Impact of Bisphenol A on the Cardiovascular System — Epidemiological and Experimental Evidence and Molecular Mechanisms
abstract: Bisphenol A (BPA) is a ubiquitous plasticizing agent used in the manufacturing of polycarbonate plastics and epoxy resins. There is well-documented and broad human exposure to BPA. The potential risk that BPA poses to the human health has attracted much attention from regulatory agencies and the general public, and has been extensively studied. An emerging and rapidly growing area in the study of BPA’s toxicity is its impact on the cardiovascular (CV) system. Recent epidemiological studies have shown that higher urinary BPA concentration in humans is associated with various types of CV diseases, including angina, hypertension, heart attack and coronary and peripheral arterial disease. Experimental studies have demonstrated that acute BPA exposure promotes the development of arrhythmias in female rodent hearts. Chronic exposure to BPA has been shown to result in cardiac remodeling, atherosclerosis, and altered blood pressure in rodents. The underlying mechanisms may involve alteration of cardiac Ca2+ handling, ion channel inhibition/activation, oxidative stress, and genome/transcriptome modifications. In this review, we discuss these recent findings that point to the potential CV toxicity of BPA, and highlight the knowledge gaps in this growing research area.

title: Physiological response of cardiac tissue to bisphenol A: alterations in ventricular pressure and contractility.
abstract: Biomonitoring studies have indicated that humans are routinely exposed to bisphenol A (BPA), a chemical that is commonly used in the production of polycarbonate plastics and epoxy resins. Epidemiological studies have shown that BPA exposure in humans is associated with cardiovascular disease; however, the direct effects of BPA on cardiac physiology are largely unknown. Previously, we have shown that BPA exposure slows atrioventricular electrical conduction, decreases epicardial conduction velocity, and prolongs action potential duration in excised rat hearts. In the present study, we tested if BPA exposure also adversely affects cardiac contractile performance. We examined the impact of BPA exposure level, sex, and pacing rate on cardiac contractile function in excised rat hearts. Hearts were retrogradely perfused at constant pressure and exposed to 10(-9)-10(-4) M BPA. Left ventricular developed pressure and contractility were measured during sinus rhythm and during pacing (5, 6.5, and 9 Hz). Ca(2+) transients were imaged from whole hearts and from neonatal rat cardiomyocyte layers. During sinus rhythm in female hearts, BPA exposure decreased left ventricular developed pressure and inotropy in a dose-dependent manner. The reduced contractile performance was exacerbated at higher pacing rates. BPA-induced effects on contractile performance were also observed in male hearts, albeit to a lesser extent. Exposure to BPA altered Ca(2+) handling within whole hearts (reduced diastolic and systolic Ca(2+) transient potentiation) and neonatal cardiomyocytes (reduced Ca(2+) transient amplitude and prolonged Ca(2+) transient release time). In conclusion, BPA exposure significantly impaired cardiac performance in a dose-dependent manner, having a major negative impact upon electrical conduction, intracellular Ca(2+) handing, and ventricular contractility.

title: Bisphenol S rapidly depresses heart function through estrogen receptor-β and decreases phospholamban phosphorylation in a sex-dependent manner
abstract: The health effects of the endocrine disruptor Bisphenol A (BPA) led to its partial replacement with Bisphenol S (BPS) in several products including food containers, toys, and thermal paper receipts. The acute effects of BPS on myocardial contractility are unknown. We perfused mouse hearts from both sexes for 15 min with physiologically relevant doses of BPS or BPA. In females BPS (1 nM) decreased left ventricular systolic pressure by 5 min, whereas BPA (1 nM) effects were delayed to 10 min. BPS effects in male mice were attenuated. In both sexes ER-β antagonism abolished the effects of BPS. Cardiac myofilament function was not impacted by BPS or BPA in either sex, although there were sex-dependent differences in troponin I phosphorylation. BPS increased phospholamban phosphorylation at S16 only in female hearts, whereas BPA reduced phosphorylation in both sexes. BPA decreased phospholamban phosphorylation at T17 in both sexes while BPS caused dephosphorylation only in females. This is the first study to compare sex differences in the acute myocardial response to physiologically relevant levels of BPS and BPA, and demonstrates a rapid ability of both to depress heart function. This study raises concerns about the safety of BPS as a replacement for BPA.

title: Association of Urinary Bisphenol A Concentration with Heart Disease: Evidence from NHANES 2003/06
abstract: Bisphenol A (BPA) is a high production volume chemical widely used in food and drinks packaging. Associations have previously been reported between urinary BPA concentrations and heart disease, diabetes and liver enzymes in adult participants of the National Health and Nutrition Examination Survey (NHANES) 2003/04. We aimed to estimate associations between urinary BPA concentrations and health measures in NHANES 2005/06 and in data pooled across collection years.  A cross-sectional analysis of NHANES: subjects were n = 1455 (2003/04) and n = 1493 (2005/06) adults aged 18–74 years, representative of the general adult population of the United States. Regression models were adjusted for age, sex, race/ethnicity, education, income, smoking, BMI, waist circumference, and urinary creatinine concentration. Main outcomes were reported diagnoses of heart attack, coronary heart disease, angina and diabetes and serum liver enzyme levels. Urinary BPA concentrations in 2005/06 (geometric mean 1.79 ng/ml, 95% CI: 1.64 to 1.96) were lower than in 2003/04 (2.49 ng/ml, CI: 2.20 to 2.83, difference p-value = 0.00002). Higher BPA concentrations were associated with coronary heart disease in 2005/06 (OR per z-score increase in BPA = 1.33, 95%CI: 1.01 to 1.75, p = 0.043) and in pooled data (OR = 1.42, CI: 1.17 to 1.72, p = 0.001). Associations with diabetes did not reach significance in 2005/06, but pooled estimates remained significant (OR = 1.24, CI: 1.10 to 1.40, p = 0.001). There was no overall association with gamma glutamyl transferase concentrations, but pooled associations with alkaline phosphatase and lactate dehydrogenase remained significant.  Higher BPA exposure, reflected in higher urinary concentrations of BPA, is consistently associated with reported heart disease in the general adult population of the USA. Studies to clarify the mechanisms of these associations are urgently needed.

title: Associations of Bisphenol A Exposure With Heart Rate Variability and Blood Pressure
abstract: Bisphenol A (BPA) is a high-volume production chemical that has been suspected to have adverse health effects. Recent studies have suggested that cardiovascular diseases are associated with the BPA exposure. The aim of present study was to investigate the associations of urinary BPA with heart rate variability and blood pressure. We recruited 560 noninstitutionalized elderly citizens from August 2008 to August 2010 in Seoul. All of the participants were ≥60 years old. The participants took medical examinations ⩽5 times. Urinary BPA concentration, heart rate variability, and blood pressure were measured at each time. A total of 1511 observations from 521 participants were included in the analyses. We observed that urinary BPA was associated negatively with the root mean square of successive differences for heart rate and positively with blood pressure. The odds ratio of showing hypertension (systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg) was 1.27 (95% CI, 0.85–1.88) in the fourth quartile compared with the first quartile of urinary BPA concentration. When the analyses were restricted to participants who did not report previous history of hypertension (n=258), the odds ratio was increased to 2.35 (95% CI, 1.33–4.17).

title: Associations between circulating levels of bisphenol A and phthalate metabolites and coronary risk in the elderly.
abstract: Studies have pointed out associations between various chemicals with estrogenic activity and cardiovascular disease. Being ubiquitous, the plastic additive substances bisphenol A (BPA), and phthalates have been detected in almost all types of analyzed human samples. The aim of this study was to investigate whether circulating levels of BPA and/or four selected phthalate metabolites are associated to coronary risk in an elderly population. In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, coronary risk was assessed by the Framingham Risk Score (FRS) together with circulating serum levels of BPA and the four phthalate metabolites monoisobutyl phthalate (MiBP), monomethyl phthalate (MMP), monoethyl phthalate (MEP), mono-(2-ethylhexyl) phthalate (MEHP) in 1016 subjects aged 70 years. BPA, MEHP, and MMP were associated to LDL-cholesterol and MEHP to HDL-cholesterol, MEP to diastolic blood pressure and MiBP to fasting glucose when the compounds were investigated one by one. After Bonferronni correction, only the relations for MMP to LDL-cholesterol (p<0.0001), MEP to diastolic blood pressure (p<0.0002), and MiBP to fasting glucose (p<0.0001) remained significant. MMP was associated to the FRS (p=0.02), but after Bonferronni correction, this association was not significant. In conclusion, associations were found between MMP and LDL-cholesterol, MEP and diastolic blood pressure, and MiBP and fasting glucose. We did not observe any strong associations between BPA nor any of the four phthalate metabolites and Framingham Risk Score in this elderly population.

title: Inhibition of L-type calcium channels by Bisphenol A in rat aorta smooth muscle.
abstract: Bisphenol A (BPA) is an endocrine disrupting chemical used on a wide range in industry. This compound has been used in the production of polycarbonate plastics and epoxy resins. For this reason and their global use, BPA is one of the most common environmental chemicals to which humans are exposed. This exposure can cause several adverse health outcomes, including at the cardiovascular level. The regulation of ion channels in vascular smooth muscle is pivotal and important for vasoreactivity, and changes in their flux can be involved in the pathophysiology of some cardiovascular diseases. This study aims to analyse in rat aorta whether the vasorelaxant effect of BPA is mediated by L-type Ca2+ channels inhibition. Using male Wistar rat aorta artery rings in the organ bath we analysed the contractility, and to study the activity of calcium current in A7r5 cells we used the whole cell configuration of Patch Clamp technique. Regarding the contractility experiences we observed that in both NA and KCl contraction, BPA caused a rapid and concentration-dependent relaxation. The electrophysiology experiments showed that BPA inhibited the basal and BAY K8644-stimulated whole-cell L-type Ca2+ channel (W-CLTCC) currents, indicating that this drug blocks the L-type Ca2+ channels. Our results suggest that BPA inhibits the W-CLTCC, leading to the relaxation of vascular smooth muscle.

title: Bisphenol A and octylphenol exacerbate type 1 diabetes mellitus by disrupting calcium homeostasis in mouse pancreas.
abstract: In pancreatic β cells, which produce and secrete insulin, Ca2+ signals contribute to insulin production and secretion. Bisphenol A (BPA) and octylphenol (OP) are reported to increase plasma insulin levels and insulin transcription factors, but regulation of plasma glucose levels did not decrease proportionally to the insulin increase. We hypothesized that BPA and OP disrupt calcium homeostasis resulting in insulin resistance through induction of endoplasmic reticulum (ER) stress. BPA and OP treatment leads to survival of pancreatic β cells against streptozotocin, but despite an increased insulin level, serum glucose regulation is not properly regulated. The expression of genes involved in transporting calcium ions to the cytosol and ER decreased while the expression of those affecting the removal of calcium from the cytosol and ER increased. Depletion of calcium from the ER leads to ER stress and can induce insulin resistance. Insulin resistance is also confirmed by insulin-responsive gene, such as glucose transporter 4 (GLUT4) and IRS2, expression. Taken together, these results imply that disruption of calcium homeostasis by BPA and OP induces ER stress and leads to insulin resistance, especially in a streptozotocin (STZ) -induced type 1 diabetes mellitus model.

title: Effects of perinatal exposure to BPA and its alternatives (BPS, BPF and BPAF) on hepatic lipid and glucose homeostasis in female mice adolescent offspring.
abstract: The widespread application of bisphenols (BPs) makes them ubiquitous in the natural environment and poses many potential risks. In this study, we examined the effects of perinatal exposure to BPA and its 3 alternatives (BPS, BPF, and BPAF) on lipid and glucose homeostasis in female mice adolescent offspring. Specifically, BPA exposure promoted the expression of hepatic lipid synthesis and fatty acid accumulation genes, resulting in a significant increase in 2 free fatty acids contents. BPS exposure caused an increase in 6 free fatty acids and triglyceride contents through promoting the expression of fatty acid synthesis, triglyceride synthesis and fatty acid accumulation genes and inhibiting the expression of fatty acid β-oxidation genes. Interestingly, BPAF exposure showed completely opposite effects on hepatic lipid metabolism compared to BPS exposure. 9 free fatty acids and triglycerides contents in the liver were significantly reduced. In particular, BPF exposure caused decreases in 2 free fatty acids contents, but no significant changes were found in the genes for lipid metabolism. In addition, unlike BPA and BPF exposure, BPS and BPAF exposure also resulted in significant increases in glucose and glycogen contents in the liver by activation of Fxr-Shp pathway and glycolysis, and inhibition of gluconeogenesis. The results showed that compared to BPA and BPF exposure, BPS and BPAF exposure significantly regulated the expression of genes related to glucose and lipid metabolism and severely interfered with hepatic lipid and glucose homeostasis. This suggested that we should thoroughly evaluate the potential health risks of BPA and its alternatives.

title: Effects of perinatal exposure to BPA, BPF and BPAF on liver function in male mouse offspring involving in oxidative damage and metabolic disorder.
abstract: Bisphenols (BPs) are common environmental pollutants that are ubiquitous in the natural environment and can affect human health. In this study, we explored the effects of perinatal exposure to BPA, BPF and BPAF on liver function involving in oxidative damage and metabolic disorders in male mouse offspring. We found that BPA exposure impairs the antioxidant defense system, increases lipid peroxidation, and causes oxidative damage in the liver. Furthermore, the levels of 13 metabolites were significantly altered following BPA exposure. We found that BPF exposure significantly increased the expression and activity of CAT, suggesting disturbances in the antioxidant defense system. Moreover, BPF exposure led to metabolic disorders in the liver due to changes in the levels of 8 key metabolites. Exposure to BPAF caused no negative effects on oxidative damage, but altered the levels of β-glucose and glycogen. In summary, perinatal exposure to BPA, BPF and BPAF differentially influence oxidative damage and metabolic disorders in the livers of male mouse offspring. The impact of early life exposure to BPs now warrants future investigations.

title: Bisphenol A Induces Hepatotoxicity through Oxidative Stress in Rat Model
abstract: Reactive oxygen species (ROS) are cytotoxic agents that lead to significant oxidative damage. Bisphenol A (BPA) is a contaminant with increasing exposure to it and exerts both toxic and estrogenic effects on mammalian cells. Due to limited information concerning the effect of BPA on liver, this study investigates whether BPA causes hepatotoxicity by induction of oxidative stress in liver. Rats were divided into five groups: The first four groups, BPA (0.1, 1, 10, 50 mg/kg/day) were administrated orally to rats for four weeks. The fifth group was taken water with vehicle. The final body weights in the 0.1 mg group showed a significant decrease compared to control group. Significant decreased levels of reduced glutathione, superoxide dismutase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase and catalase activity were found in the 50 mg BPA group compared to control groups. High dose of BPA (50 mg/kg) significantly increased the biochemical levels of ALT, ALP and total bilirubin. BPA effect on the activity of antioxidant genes was confirmed by real time PCR in which the expression levels of these genes in liver tissue were significantly decrease compared to control. Data from this study demonstrate that BPA generate ROS and reduce the antioxidant gene expression that causes hepatotoxicity.

title: Identification of Environmental Chemicals Associated with the Development of Toxicant-associated Fatty Liver Disease in Rodents
abstract: Toxicant-associated fatty liver disease (TAFLD) is a recently identified form of nonalcoholic fatty liver disease (NAFLD) associated with exposure to industrial chemicals and environmental pollutants. Numerous studies have been conducted to test the association between industrial chemicals/environmental pollutants and fatty liver disease both in vivo and in vitro.  The objective of the article is to report a list of chemicals associated with TAFLD.  Two federal databases of rodent toxicology studies—Toxicological Reference Database (ToxRefDB; Environmental Protection Agency) and Chemical Effects in Biological Systems (CEBS, National Toxicology Program)—were searched for liver end points. Combined, these 2 databases archive nearly 2,000 rodent studies. Toxicant-associated steatohepatitis (TASH) descriptors including fatty change, fatty necrosis, Oil red O-positive staining, steatosis, and lipid deposition were queried.  Using these search terms, 123 chemicals associated with fatty liver were identified. Pesticides and solvents were the most frequently identified chemicals, while polychlorinated biphenyls (PCBs)/dioxins were the most potent. About 44% of identified compounds were pesticides or their intermediates, and >10% of pesticide registration studies in ToxRefDB were associated with fatty liver. Fungicides and herbicides were more frequently associated with fatty liver than insecticides.  More research on pesticides, solvents, metals, and PCBs/dioxins in NAFLD/TAFLD is warranted due to their association with liver damage.

title: Bisphenol A Causes Liver Damage and Selectively Alters the Neurochemical Coding of Intrahepatic Parasympathetic Nerves in Juvenile Porcine Models under Physiological Conditions
abstract: Bisphenol A (BPA) is an extremely common polymer that is used in typical everyday products throughout the world, especially in food and beverage containers. Within the last ten years, it has been found that the BPA monomer tends to leach into foodstuffs, and nanogram concentrations of it may cause a variety of deleterious health effects. These health problems are very evident in developing children and in young adults. The aim of this study was to expose developing pigs to dietary BPA at both legally acceptable and ten-fold higher levels. Livers that had been exposed to BPA showed vacuolar degeneration, sinusoidal dilatation, vascular congestion and glycogen depletion that increased with exposure levels. Furthermore, the livers of these models were then examined for irregularities and double-labeled immunofluorescence was used to check the innervated hepatic samples for varying neuronal expression of selected neuronal markers in the parasympathetic nervous system (PSNS). It was found that both the PSNS and all of the neuronal markers showed increased expression, with some of them being significant even at recommended safe exposure levels. The implications are quite serious since these effects have been observed at recommended safe levels with expression increasing in-line with exposure levels. The increased neuronal markers studied here have been previously correlated with behavioral/psychological disorders of children and young adults, as well as with childhood obesity and diabetes. However, further research must be performed in order to develop a mechanism for the above-mentioned correlations.

title: Activation of Sirtuin 3 and Maintenance of Mitochondrial Integrity by N-Acetylcysteine Protects Against Bisphenol A-Induced Kidney and Liver Toxicity in Rats
abstract: Mitochondrial impairment ensuing from oxidative imbalance is related to adverse consequences of bisphenol A (BPA), a globally utilized industrial chemical. Recent evidence reveals sirtuin 3 (SIRT3) as a key regulator of mitochondrial homeostasis; however, its role in BPA toxicity remains unidentified. This study explored the potential benefits of N-acetylcysteine (NAC), an effective antioxidant, against BPA toxicity in the kidney and liver, and examined whether SIRT3 was involved in this condition. Male Wistar rats were fed with vehicle, BPA (5, 50 mg/kg), BPA (50 mg/kg) plus NAC (100 mg/kg) and were evaluated after 5 weeks. NAC treatment significantly diminished BPA-induced kidney and liver functional disorders, histopathological alterations, oxidative stress, and apoptosis. The increased mitochondrial reactive oxygen species, the disrupted membrane potential, the swelling, and the impaired mitochondrial fission caused by BPA were also mitigated upon concurrent treatment with NAC. The benefits of NAC were associated with enhanced AMPK-PGC-1α-SIRT3 signaling protein expressions, which led to decreased acetylation of superoxide dismutase 2 (SOD2) and increased expression of mitochondrial antioxidant manganese superoxide dismutase (MnSOD). The findings demonstrate the efficacy of NAC in protecting BPA-induced kidney and liver injury, which, in part, is mediated by activating SIRT3 and improving mitochondrial function, dynamics, and oxidative imbalance.

title: Human exposure to Bisphenol A and liver health status: Quantification of urinary and circulating levels by LC–MS/MS
abstract: &NA; A selective and highly sensitive analytical methodology for determination of Bisphenol A in human plasma was developed and validated. The method was based on selective liquid/solid extraction, combined with liquid chromatography–electrospray ionization tandem mass spectrometry in the multiple reaction monitoring mode and negative ionization. The linearity of the detector response was verified in human plasma over the concentration range 0.100–200 ng mL−1. The detection limit was 0.03 ng mL−1 and the quantification limit was 0.100 ng mL−1. The analytical features of the proposed in‐house validated method were satisfactory: precision was <10% and recoveries were around 84–104%. The matrix effect was studied and compensated using deuterated labeled standard. The applicability of the proposed method was demonstrated analyzing human plasma samples from individuals affected by non‐alcoholic fatty liver disease. Bisphenol A was detected above the detection limit in all samples. The data show a persistence of unconjugated Bisphenol A levels in plasma and indicate a chronic Bisphenol A exposure of the target organ, suggesting an association between liver health status and Bisphenol A exposure. The results from our study are valuable for further investigation with large sample size and longitudinal study designs, necessary to confirm the observed association.

title: Bisphenol A Impairs Mitochondrial Function in the Liver at Doses below the No Observed Adverse Effect Level
abstract: Bisphenol A (BPA) has been reported to possess hepatic toxicity. We investigated the hypothesis that BPA, below the no observed adverse effect level (NOAEL), can induce hepatic damage and mitochondrial dysfunction by increasing oxidative stress in the liver. Two doses of BPA, 0.05 and 1.2 mg/kg body weight/day, were administered intraperitoneally for 5 days to mice. Both treatments impaired the structure of the hepatic mitochondria, although oxygen consumption rate and expression of the respiratory complex decreased only at the higher dose. The hepatic levels of malondialdehyde (MDA), a naturally occurring product of lipid peroxidation, increased, while the expression of glutathione peroxidase 3 (GPx3) decreased, after BPA treatment. The expression levels of proinflammatory cytokines such as interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) also increased. In HepG2 cells, 10 or 100 nM of BPA also decreased the oxygen consumption rate, ATP production, and the mitochondrial membrane potential. In conclusion, doses of BPA below the NOAEL induce mitochondrial dysfunction in the liver, and this is associated with an increase in oxidative stress and inflammation.

title: Bisphenol A disturbed the lipid metabolism mediated by sterol regulatory element binding protein 1 in rare minnow Gobiocypris rarus.
abstract: Bisphenol A (BPA), a representative endocrine disrupting compound, exists ubiquitously in the aquatic environment. Several studies on fish have validated the role of BPA in the lipid metabolism. However, the action mechanisms of BPA on lipid metabolism have been little studied. To clarify how BPA regulates lipid metabolism, Gobiocypris rarus were exposed to 15 μg/L BPA for 3 and 6 weeks. Results showed that BPA altered lipid content by regulating some metabolism-related genes. The BPA's inhibiting effect on fatty acid β-oxidation might be stronger than on lipid synthesis. BPA disturbed the expression of acaca (acetyl-CoA carboxylase), fasn (fatty acid synthase) and cpt1α (carnitine palmitoyltransferase 1α) by altering the sterol regulatory element binding protein 1 (SREBP-1) binding to their sterol regulatory elements (SREs). Our result also revealed that DNA methylation in the 5' flanking regions of cpt1α could perturb the SREBP-1 binding adjacent to its SRE in females under BPA exposure. Besides, BPA exposure led to gender-specific effect on fatty acid β-oxidation in G. rarus. This will contribute to our understanding of the regulation mechanisms of BPA on lipid metabolism in fish.

title: Bisphenol-A impairs memory and reduces dendritic spine density in adult male rats.
abstract: Exposure to Bisphenol-A (BPA), an endocrine disruptor used in plastics, occurs in the United States on a daily basis. Recent studies suggest exposure during development causes memory deficits later in life; however, the ramifications of exposure in adulthood are unclear. We examined the effects of acute BPA administration (40 μg/kg) on memory and synaptic plasticity in adult male rats. BPA significantly impaired both visual and spatial memory and decreased dendritic spine density on pyramidal cells in CA1 and the medial prefrontal cortex (mPFC). Additionally, BPA significantly decreased PSD-95, a synaptic marker, in the hippocampus and increased cytosolic pCREB, a transcription factor, in mPFC. Together, these findings show that a single dose of BPA, below the USEPA reference safe daily limit of 50 μg/kg/day, may block the formation of new memories by interfering with neural plasticity processes in the adult brain.

title: Sensitive neurotoxicity assessment of bisphenol A using double immunocytochemistry of DCX and MAP2
abstract: Bisphenol A (BPA) is an environmental toxin widely used in manufacturing industries. Studies conducted on the neurotoxicity of BPA demonstrated that at excessive, high concentrations (≥ 200 µM) adverse responses occurred which were not detectable using traditional toxicity tests at lower chemical quantities than 200 µM. Thus, a method capable of effectively detecting neurotoxicity at low concentrations (≤ 100 µM) was devised. Bisphenol A-mediated neurotoxicity was examined in primary cultured neurons using various methods, including Western blot, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity and reactive oxygen species assays. These methods confirmed BPA-induced toxicity at 200 μM, but no marked effect was observed at concentrations below 200 μM. However, when immunocytochemistry (ICC) was performed using a co-immunofluorescence assay of doublecortin (DCX) and microtubule-associated protein 2 (MAP2), BPA adversely affected neuronal maturation in neural progenitor cells at concentrations as low as 100 µM, at which the three traditional methods failed to detect any neurotoxic effect. Our DCX/MAP2 ICC findings indicate that low concentrations of BPA are toxic to developing neurons, and suggest that the devised double ICC technique might provide an effective means of assessing neurotoxic effects of environmental toxins at low concentrations.

title: Bisphenol A exposure and children’s behavior: A systematic review
abstract: Bisphenol A (BPA) is an endocrine disrupting chemical used to synthesize polycarbonate plastics and epoxy resins. Previous research suggests that exposure to it can alter children’s behavior. The objective of this study is to conduct a systematic review of the existing literature, examining associations between prenatal and childhood BPA exposure and behavior in children up to 12 years of age. We searched electronic bibliographic databases (MEDLINE, PubMed, EMBASE, PsycINFO, CINAHL, and ERIC), reference lists of included articles, and conference abstracts (American Psychiatric Association, American Academy of Neurology, Pediatric Academic Societies, and International Society of Environmental Epidemiology). We included original studies reporting on the association between prenatal and childhood BPA exposure that measured BPA metabolites in urine and children’s behavioral outcomes. From 2811 citations, 11 articles met our inclusion criteria. Descriptive analyses indicated that prenatal exposure to maternal BPA concentrations were related to higher levels of anxiety, depression, aggression, and hyperactivity in children. BPA exposure in childhood was associated with higher levels of anxiety, depression, hyperactivity, inattention, and conduct problems. Limited observational evidence suggests an association between both prenatal and childhood exposure to BPA and adverse behavioral outcomes in children. Prospective cohort studies are needed to clarify these associations.

title: Prenatal and early childhood bisphenol A concentrations and behavior in school-aged children.
abstract: Early life exposure to bisphenol A (BPA), an endocrine disrupting chemical used in some food and beverage containers, receipts, and dental sealants, has been associated with anxiety and hyperactivity in animal studies. A few human studies also show prenatal and childhood BPA exposure to be associated with behavior problems in children.



We measured BPA in urine from mothers during pregnancy and children at 5 years of age (N=292). Child behavior was assessed by mother and teacher report at age 7 years and direct assessment at age 9 years.



Prenatal urinary BPA concentrations were associated with increased internalizing problems in boys, including anxiety and depression, at age 7. No associations were seen with prenatal BPA concentrations and behaviors in girls. Childhood urinary BPA concentrations were associated with increased externalizing behaviors, including conduct problems, in girls at age 7 and increased internalizing behaviors and inattention and hyperactivity behaviors in boys and girls at age 7.



This study adds to the existing literature showing associations of early life BPA exposure with behavior problems, including anxiety, depression, and hyperactivity in children. Additional information about timing of exposure and sex differences in effect is still needed.

title: Prenatal bisphenol A exposure and maternally reported behavior in boys and girls.
abstract: Prenatal exposure to gonadal hormones plays a major role in the normal development of the male and female brain and sexually dimorphic behaviors. Hormone-dependent differences in brain structure and function suggest that exposure to exogenous endocrine disrupting chemicals may be associated with sex-specific alterations in behavior. Bisphenol A (BPA) is an environmental chemical that has been shown to alter estrogen, androgen, and thyroid hormone signaling pathways. Epidemiological and experimental studies suggest associations between prenatal exposure to BPA and child behavior, however data are inconsistent, and few studies have examined school age children. We examined BPA concentration in spot urine samples from women at mean 27 weeks of pregnancy in relation to child behavior assessed at age 6-10 years using the parent-completed Child Behavior Checklist (CBCL). We report associations between maternal BPA urinary concentrations and several CBCL scores in 153 children (77 boys and 76 girls). We observed a significant interaction between maternal urinary BPA and sex for several behaviors (externalizing, aggression, Anxiety Disorder, Oppositional/Defiant Disorder and Conduct Disorder traits), but no significant associations between BPA and scores on any CBCL scales. However in analyses restricted to children of mothers with detectable prenatal urinary BPA (n=125), BPA was associated with moderately increased internalizing and externalizing behaviors, withdrawn/depressed behavior, somatic problems, and Oppositional/Defiant Disorder traits in boys. In addition we observed a significant interaction between BPA and sex for several behaviors (externalizing, withdrawn/depressed, rule-breaking, Oppositional/Defiant Disorder traits, and Conduct Disorder traits). These results suggest that prenatal exposure to BPA may be related to increased behavior problems in school age boys, but not girls.

title: Bisphenol A Exposure in Children With Autism Spectrum Disorders
abstract: The etiology of autism spectrum disorders (ASD) is believed to involve genetic and environmental components. This study focused on the plasticizer, Bisphenol‐A (BPA). The major pathway for BPA metabolism and excretion is via glucuronidation. To determine whether there was a relationship between BPA exposure and ASD, urine specimens were collected from 46 children with ASD and 52 controls. Free and total BPA concentrations were determined by mass spectrometry. The fraction glucuronidated was calculated from the difference. A metabolomics study was done to investigate metabolite distribution in the urine. (i) Most of the BPA excreted in the urine was as the glucuronide; (ii) about 20% of the ASD children had BPA levels beyond the 90th percentile (>50 ng/mL) of the frequency distribution for the total sample of 98 children; (iii) Mann–Whitney U tests and multiple regression analyses found significant differences (P < 0.05) between the groups in total and % bound BPA; and (iv) the metabolomics analyses showed the number of absolute partial correlations >|0.30| between metabolite concentrations and total BPA was ∼3 times greater with the ASD group than the controls (P < 0.001), and the number of absolute partial correlations > |0.30| for % bound BPA was ∼15 times higher with ASD (P < 0.001). The results suggest there is an association between BPA and ASD.

title: Prenatal and lactational exposure to low-doses of bisphenol A alters brain monoamine concentration in adult mice
abstract: Bisphenol A (BPA) is an endocrine-disrupting chemical, widely used in industry and dentistry. We have previously reported that BPA affects murine neocortical development by accelerating neuronal differentiation/migration resulting in abnormal neocortical architecture as well as apparent thalamocortical connections in adult mice brains. The aim of this study was to investigate whether or not prenatal and lactational BPA-exposure affects the level of neurotransmitters in mice brains. Pregnant mice were injected subcutaneously with 20μg/kg of BPA daily from embryonic day 0 (E0) until postnatal day 21 (P21). Control animals received a vehicle alone. The brains were removed and dissected into six regions for biochemical assays (n=7-8) at postnatal 3 weeks (P3W) and P10-15W. The concentration of the neurotransmitters was determined by high-performance liquid chromatography. The levels of dopamine and its metabolite significantly increased in the caudate/putamen and dorsal raphe nucleus, whereas serotonin and its metabolite increased in the caudate/putamen, dorsal raphe nucleus, thalamus and Substantia nigra in the BPA-exposure group at both P3W and/or P14-15W. These results suggested that prenatal and lactational BPA-exposure might perturb the neurotransmitter system in adult mice.

title: Prenatal and lactational exposure to low-doses of bisphenol A alters adult mice behavior
abstract: Bisphenol A (BPA) is an endocrine-disrupting chemical, widely used in dentistry and various industries. We previously reported that BPA affected murine neocortical development by accelerating neuronal differentiation/migration, resulting in abnormal neocortical architecture as well as aberrant thalamocortical connections in the brains of adult mice. The aim of this study was to investigate whether prenatal and lactational BPA exposure affected behavior in adult mice. Pregnant mice were injected subcutaneously with 20μg/kg of BPA daily from embryonic day 0 (E0) until postnatal day 21 (P21). Control animals received a vehicle alone. Behavioral tests (n=15-20) were conducted at postnatal 3weeks (P3W) and P10-15W. After an open-field test, an elevated plus maze and Morris water maze tests were performed. The total distance in the elevated plus maze test at P3W and in the open-field test at P10W was significantly decreased in the BPA-exposed group, compared with the control group. Significant sex differences were observed in the time spent in the central area in the open-field test at P3W and in the total distance in the elevated plus maze test at P11W. These results indicated that prenatal and lactational BPA exposure disturbed the murine behavior in the postnatal development period and the adult mice.

title: Bisphenol A exposure remodels cognition of male rats attributable to excitatory alterations in the hippocampus and visual cortex.
abstract: Bisphenol A, an environmental xenoestrogen, has been shown sex-specific adverse effects on cognitive function of rodents. However, the specific mechanisms underlying these outcomes remain elusive, limiting our understanding the differences in behavioral impairments due to BPA exposure between genders in humans. The present study chose the juvenile stage (with a stable estrogen level) as the exposure window to explore BPA effects on cognitive behaviors of male and female Sprague-Dawley (SD) rats and related mechanisms. Three dosages of BPA (0.04, 0.4 and 4 mg/kg/day) were chose to make BPA-exposed models. Especially, the mid-dose for rats was close to the current reference daily limit for human exposure given by the U.S. Environmental Protection Agency. Our results showed that male but not female juvenile rats had a marked decline in spatial memory after 0.4 mg/kg/day BPA exposure, which accompanied with downregulation of glutamate receptor (NR2) expression in their hippocampus and primary visual cortex (V1). In the high-dose BPA exposed groups (4 mg/kg/day), there was not only a deficit of spatial memory, but also an anxiety-like behavior of male rats. Additionally, those rats had a significant decline in spine density of pyramidal neurons and a decreased expression of glutamate receptor subtypes (NR2 and GluR1) in the hippocampus. Importantly, such impairments in the hippocampus of male rats were associated with a decrease of glutamate receptor (NR2) expression in the V1, which could perturb the visual information inputs. To some extent, altered ERβ expression within their hypothalamus could contribute to the anxiety-like behavior after high-dose BPA exposure. However, the low-dose BPA exposed juvenile rats didn't present any structural and behavioral changes in our present study. Those results suggests that BPA exerts dose dependent and gender-specific effects on the cognition of juvenile animals. Our findings shed light on mechanisms underlying BPA effects on the juvenile animals.

title: Signaling pathways of bisphenol A–induced apoptosis in hippocampal neuronal cells: Role of calcium‐induced reactive oxygen species, mitogen‐activated protein kinases, and nuclear factor–κB
abstract: In the present study, we investigated the neurotoxicity of bisphenol A [BPA; 2,2‐bis‐(4 hydroxyphenyl) propane] and the underlying mechanisms of action in mouse hippocampal HT‐22 cells. BPA, known to be a xenoestrogen, is used in the production of water bottles, cans, and teeth suture materials. BPA‐treated HT‐22 cells showed lower cell viability than did controls at concentrations of BPA over 100 μM. BPA induced apoptotic cell death as indicated by staining with Hoechst 33258, costaining with Annexin V/propidium iodide, and activation of caspase 3. BPA regulated the generation of reactive oxygen species (ROS) by increasing intracellular calcium. BPA activated phosphorylation of extracellular signal–regulated kinase (ERK) and c‐Jun N‐terminal kinase (JNK), and nuclear translocation of nuclear factor (NF)‐κB. Pretreatment with specific inhibitors for calcium, ROS, ERK, and JNK decreased BPA‐induced cell death; however, inhibitor for NF‐κB increased BPA‐induced cell death. The results suggest that calcium, ROS, ERK, and JNK are involved in BPA‐induced apoptotic cell death in HT‐22 cells. In contrast, an NF‐κB cascade was activated for survival signaling after BPA treatment.

title: Neurochemical impact of bisphenol A in the hippocampus and cortex of adult male albino rats
abstract: Bisphenol A (BPA), an endocrine-disrupting chemical, is widely used in the manufacture of polycarbonated plastics and epoxy resins and line metal beverage cans. Growing evidence suggests that BPA acts directly on neuronal functions as it is lipophilic and could accumulate in the brain. The present study aims to investigate the effect of two doses of BPA (10 mg/kg for 6 and 10 weeks and 25 mg/kg for 6 weeks) on excitatory (glutamate and aspartate) and inhibitory (γ-aminobutyric acid, glycine, and taurine) amino acid neurotransmitter levels in the cortex and hippocampus. This study extends to investigate the effect of BPA on acetylcholinesterase (AchE) activity and some oxidative stress parameters in the two regions. In the cortex, a significant increase in the excitatory and a significant decrease in the inhibitory amino acids occurred after BPA (10 mg/kg for 10 weeks and 25 mg/kg for 6 weeks). This was accompanied by a significant increase in lipid peroxidation, nitric oxide, and reduced glutathione after 6 weeks of BPA (25 mg/kg). In the hippocampus, a significant increase in the excitatory and inhibitory amino acid neurotransmitters occurred after 6 weeks of BPA. Hippocampal lipid peroxidation increased significantly after BPA exposure and hippocampal reduced glutathione increased significantly after 6 weeks of BPA exposure (10 mg/kg). BPA induced a significant increase in cortical and hippocampal AchE activity. The present neurochemical changes in the cortex and hippocampus suggest that BPA induced a state of excitotoxicity and oxidative stress. This may raise concerns about the exposure of humans to BPA due to its wide applications in industry.

title: Neurotoxicity of low bisphenol A (BPA) exposure for young male mice: Implications for children exposed to environmental levels of BPA.
abstract: To investigate the neuron toxicities of low-dose exposure to bisphenol A (BPA) in children, mice were used as an animal model. We examined brain cell damage and the effects of learning and memory ability after BPA exposure in male mice (4 weeks of age) that were divided into four groups and chronically received different BPA treatments for 8 weeks. The comet assay and hippocampal neuron counting were used to detect the brain cell damage. The Y-maze test was applied to test alterations in learning and memory ability. Long term potentiation induction by BPA exposure was performed to study the potential mechanism of performance. The percentages of tail DNA, tail length and tail moment in brain cells increased with increasing BPA exposure concentrations. Significant differences in DNA damage were observed among the groups, including between the low-dose and control groups. In the Y-maze test, the other three groups qualified for the learned standard one day earlier than the high-exposed group. Furthermore, the ratio of qualified mice in the high-exposed group was always the lowest among the groups, indicating that high BPA treatment significantly altered the spatial memory performance of mice. Different BPA treatments exerted different effects on the neuron numbers of different regions in the hippocampus. In the CA1 region, the high-exposed group had a significant decrease in neuron numbers. A non-monotonic relationship was observed between the exposure concentrations and neuron quantity in the CA3 region. The hippocampal slices in the control and medium-exposed groups generated long-term potentiation after induction by theta burst stimulation, but the low-exposed group did not. A significant difference was observed between the control and low-exposed groups. In conclusion, chronic exposure to a low level of BPA had adverse effects on brain cells and altered the learning and memory ability of adolescent mice.

title: Bisphenol A inhibits proliferation and induces apoptosis in micromass cultures of rat embryonic midbrain cells through the JNK, CREB and p53 signaling pathways.
abstract: Bisphenol A (BPA) has been widely used in the manufacture of polycarbonate plastic, water bottles and food containers. Previous studies have established that BPA could cause developmental toxicity by inhibiting the proliferation and differentiation of rat embryonic midbrain (MB) cells in vitro. However, the underlying mechanisms have not been well studied yet. In the current study, we examined the proliferation and differentiation of MB cells treated with 10(-12)-10(-4)M BPA and found that only 10(-4)M BPA inhibited proliferation and differentiation. Then, we investigated the cell cycle progression and apoptosis of MB cells; 10(-4)M BPA caused an explicit S phase and G2/M phase arrest in the cell cycle and increased the percentage of apoptotic cells. Moreover, the phosphorylation of mitogen-activated protein kinase (MAPK) and cyclic-AMP response binding protein (CREB) and the expression of some apoptotic regulatory genes were investigated. BPA (10(-4)M) reduced the phosphorylation of C-Jun N-terminal kinase (JNK) and CREB, and increased the mRNA expression level of Bax and p53. Our findings demonstrated that BPA could cause developmental toxicity through anti-proliferation and pro-apoptosis in MB cells. Multiple signaling pathways, such as the JNK, CREB and p53-mitochondrial apoptosis pathways, participate in these effects.

title: Corticosterone-regulated actions in the rat brain are affected by perinatal exposure to low dose of bisphenol A
abstract: The estrogen-mimicking endocrine disrupter bisphenol A (BPA) which is used in the manufacture of plastic and epoxy resins, is one of the world's most heavily produced synthetic chemicals. BPA is detected in animal tissues, and its bio-accumulation has shown to be higher in the fetus than the mother. Exposure to doses below the daily safe limit has been reported to affect the sexual differentiation of the brain and modify the behavior of the exposed rodent offspring. The aim of the present study was to investigate in the rat the possible organizational effects of low BPA exposure on glucocorticoid-regulated responses. Female breeders were exposed to 40 microg/kg b.w. BPA daily throughout pregnancy and lactation. Plasma corticosterone levels and the two types of hippocampal corticosteroid receptors (GR and MR) were determined in mid-adolescent offspring under basal conditions and following a Y-maze task. BPA treated females had higher corticosterone levels than control females and BPA males and lower GR levels than BPA males, under basal conditions. Following the mildly stressful experience of Y-maze, corticosterone levels were increased in BPA-treated animals of both sexes, compared to the controls. GR levels were also increased in BPA-treated females compared to males. No effect of BPA was observed on MR levels, whereas the Y-maze experience significantly decreased receptors' levels in both female groups. The animals' performance in the task was also evaluated. BPA exposure significantly impaired the spatial recognition memory in both sexes, and modified the behavioural coping in a sex-dependent manner. Female BPA-treated offspring exhibited increased "anxiety-like" behaviour and dramatic loss of exploration attitude during the task, in comparison to males. This study provides for the first time evidence that corticosterone and its actions in the brain are sensitive to the programming effects of BPA at a dose below the currently acceptable daily intake.

title: Neurobehavioral effects of bisphenol S exposure in early life stages of zebrafish larvae (Danio rerio).
abstract: As an alternate of bisphenol A (BPA), bisphenol S (BPS) is now widely used to produce our daily consumer goods. Some studies have shown that BPS has the potential to disrupt the reproduction and glucose homeostasis. However, the impact of BPS on the nervous system remains unclear. The purpose of this study is to investigate the impact of BPS on the nervous systems of zebrafish in their early growing stages. The 96 h-LC50 value of BPS to zebrafish larvae was 323 mg/L (95%CI: 308-339 mg/L). Zebrafish embryos were exposed to BPS at concentrations of 0, 0.03, 0.3 and 3.0 mg/L until 6 days postfertilization. Our results showed that 0.3 and 3.0 mg/L BPS exposure markedly decreased locomotor behavior, accompany by the increased oxidative stress, promoted apoptosis and altered retinal structure in zebrafish. In addition, the expression levels of six neurodevelopment genes (α1-tubulin, elavl3, gap43, mbp, syn2a and gfap) were downregulated after 3.0 mg/L BPS treatment. In conclusion, BPS may affect locomotor behavior and alter retinal structure in zebrafish larvae partially by increasing oxidative stress, and by suppressing the expression levels of neurodevelopment genes.

title: Low-dose exposure to bisphenol A and replacement bisphenol S induces precocious hypothalamic neurogenesis in embryonic zebrafish
abstract: Here we demonstrate that bisphenol A (BPA) exposure during a time point analogous to the second trimester in humans has real and measurable effects on brain development and behavior. Furthermore, our study is the first, to our knowledge, to show that bisphenol S, a replacement used in BPA-free products, equally affects neurodevelopment. These findings suggest that BPA-free products are not necessarily safe and support a societal push to remove all structurally similar bisphenol analogues and other compounds with endocrine-disruptive activity from consumer goods. Our data here, combined with over a dozen physiological and behavioral human studies that begin to point to the prenatal period as a BPA window of vulnerability, suggest that pregnant mothers limit exposure to plastics and receipts. Bisphenol A (BPA), a ubiquitous endocrine disruptor that is present in many household products, has been linked to obesity, cancer, and, most relevant here, childhood neurological disorders such as anxiety and hyperactivity. However, how BPA exposure translates into these neurodevelopmental disorders remains poorly understood. Here, we used zebrafish to link BPA mechanistically to disease etiology. Strikingly, treatment of embryonic zebrafish with very low-dose BPA (0.0068 μM, 1,000-fold lower than the accepted human daily exposure) and bisphenol S (BPS), a common analog used in BPA-free products, resulted in 180% and 240% increases, respectively, in neuronal birth (neurogenesis) within the hypothalamus, a highly conserved brain region involved in hyperactivity. Furthermore, restricted BPA/BPS exposure specifically during the neurogenic window caused later hyperactive behaviors in zebrafish larvae. Unexpectedly, we show that BPA-mediated precocious neurogenesis and the concomitant behavioral phenotype were not dependent on predicted estrogen receptors but relied on androgen receptor-mediated up-regulation of aromatase. Although human epidemiological results are still emerging, an association between high maternal urinary BPA during gestation and hyperactivity and other behavioral disturbances in the child has been suggested. Our studies here provide mechanistic support that the neurogenic period indeed may be a window of vulnerability and uncovers previously unexplored avenues of research into how endocrine disruptors might perturb early brain development. Furthermore, our results show that BPA-free products are not necessarily safer and support the removal of all bisphenols from consumer merchandise.

title: Long‐term exposure to bisphenol S damages the visual system and reduces the tracking capability of male zebrafish (Danio rerio)
abstract: Bisphenol S (BPS) is widely detected in aquatic environments and in human bodies. BPS has reproductive and thyroid disrupting effects, but its effect on the visual system remains unknown. In the present study, zebrafish embryos were exposed to BPS at concentrations of 1, 10, 100 and 1000 μg l−1 until 120 days post‐fertilization in a semistatic system, and the effect of BPS on the visual behavior was examined using the optokinetic response and the optomotor response tests in male zebrafish. The retinal histology, mRNA expression of photoreceptor opsin genes (zfrho, zfblue, zfgr1, zfred and zfuv) and apoptosis‐related genes (bax and bcl‐2) were also assessed. Long‐term BPS exposure decreased the tracking capability of male zebrafish, consistent with structural damage to the retina. BPS induced different amounts of vacuoles in the retinal pigment epithelium, and 1000 μg l−1 BPS exposure decreased the length of the inner plexiform layer, ganglion cell layer and retina, and induced an irregular arrangement of photoreceptor cells. The expression levels of the opsin genes (zfred, zfgr1 and zfrho) were significantly elevated, indicating an enhanced spectral sensitivity to red, green and dim light to compensate for the reduction of the optomotor response. Together, the results showed for the first time that long‐term exposure to BPS damaged the structure of male zebrafish retina and reduced their tracking capability.

title: Review: Endocrine disrupting chemicals and immune responses: a focus on bisphenol-A and its potential mechanisms.
abstract: Endocrine disrupting chemicals (EDCs) have become of concern for a variety f health issues. Due to their effects on the endocrine system they have been thoroughly examined with regards to sexual dysfunction, malformation, and cancers of reproductive origin. Bisphenol-A (BPA) is a widely studied EDC and has been characterized regarding its estrogenic effects on a variety of cell types. BPA also alters immune responses. In this review, we examine some of the documented effects of EDCs, with a focus on BPA that pertain to modulation of the immune system and various immune cell populations. We highlight the multiple actions of BPA on altering T cell subsets, B cell functions, and dendritic cell and macrophage biology. Finally, we consider that these immunological activities of BPA may be mediated through estrogen receptor signaling, arylhydrocarbon receptor, and the peroxisome proliferator-activated receptor family of nuclear receptors.

title: Developmental Bisphenol A Exposure Modulates Immune-Related Diseases
abstract: Bisphenol A (BPA), used in polycarbonate plastics and epoxy resins, has a widespread exposure to humans. BPA is of concern for developmental exposure resulting in immunomodulation and disease development due to its ability to cross the placental barrier and presence in breast milk. BPA can use various mechanisms to modulate the immune system and affect diseases, including agonistic and antagonistic effects on many receptors (e.g., estrogen receptors), epigenetic modifications, acting on cell signaling pathways and, likely, the gut microbiome. Immune cell populations and function from the innate and adaptive immune system are altered by developmental BPA exposure, including decreased T regulatory (Treg) cells and upregulated pro- and anti-inflammatory cytokines and chemokines. Developmental BPA exposure can also contribute to the development of type 2 diabetes mellitus, allergy, asthma and mammary cancer disease by altering immune function. Multiple sclerosis and type 1 diabetes mellitus may also be exacerbated by BPA, although more research is needed. Additionally, BPA analogs, such as bisphenol S (BPS), have been increasing in use, and currently, little is known about their immune effects. Therefore, more studies should be conducted to determine if developmental exposure BPA and its analogs modulate immune responses and lead to immune-related diseases.

title: Effect of Bisphenol A on non-specific immunodefenses against non-pathogenic Escherichia coli.
abstract: We examined the effect of Bisphenol A (BPA) on non-specific defense in experiments with a non-pathogenic bacterium, Escherichia coli K-12. Mice were pretreated by a subcutaneous route with BPA (5 mg/kg body weight) for 5 consecutive days in the back and 3 days after the last treatment, injected by the intra-peritoneal route with E. coli K-12. BPA pretreatment caused a decrease of T and B cell populations in the spleen of treated mice. After the challenge with E. coli, the activity to eliminate bacteria from the peritoneal cavity in the early stage of infection (within 24 h) was diminished compared with non-treated mice. BPA induced the migration of excess neutrophils into the peritoneal cavity, but reduced their phagocytic activity against E. coli K-12. For macrophages and lymphocytes, BPA reduced the population in the spleen and the accumulation at infection foci. The production of MCP-1 was enhanced by BPA treatment, but that of IL-6 was suppressed after infection. These results suggest that BPA possessed immunotoxicity and reduced the non-specific host defense as an acute toxicity.

title: Developmental Exposure to Bisphenol A Modulates Innate but Not Adaptive Immune Responses to Influenza A Virus Infection
abstract: Bisphenol A (BPA) is used in numerous products, such as plastic bottles and food containers, from which it frequently leaches out and is consumed by humans. There is a growing public concern that BPA exposure may pose a significant threat to human health. Moreover, due to the widespread and constant nature of BPA exposure, not only adults but fetuses and neonates are also exposed to BPA. There is mounting evidence that developmental exposures to chemicals from our environment, including BPA, contribute to diseases late in life; yet, studies of how early life exposures specifically alter the immune system are limited. Herein we report an examination of how maternal exposure to a low, environmentally relevant dose of BPA affects the immune response to infection with influenza A virus. We exposed female mice during pregnancy and through lactation to the oral reference dose for BPA listed by the US Environmental Protection Agency, and comprehensively examined immune parameters directly linked to disease outcomes in adult offspring following infection with influenza A virus. We found that developmental exposure to BPA did not compromise disease-specific adaptive immunity against virus infection, or reduce the host’s ability to clear the virus from the infected lung. However, maternal exposure to BPA transiently reduced the extent of infection-associated pulmonary inflammation and anti-viral gene expression in lung tissue. From these observations, we conclude that maternal exposure to BPA slightly modulates innate immunity in adult offspring, but does not impair the anti-viral adaptive immune response, which is critical for virus clearance and survival following influenza virus infection.

title: Evaluation of the immune response following exposure of mice to bisphenol A: Induction of th1 cytokine and prolactin by BPA exposure in the mouse spleen cells
abstract: Bisphenol A [2, 2 bis (4-hydoxyphenyl) propane; BPA] is a widely used endocrine disruptors and has estrogenic activities. Although interests on biological effect of BPA are rising, evidences of its effect on immune system are lacking. We investigated that the effect of BPA on immune parameters to postulate the mechanism, and BPA interruptions between neuroendocrine and immune system. BPA was administrated to mice by p.o. (as a drinking water) dose on 0.015, 1.5 and 30 mg/ml for 4 weeks. The BPA treatment did not result in any change in body weight, spleen weight and distribution of lymphocyte subpopulation collected from spleen. BPA induced prolactin production in spleen, and exposure of BPA increased the activity of splenocyte proliferation in response to Con A (p<0.001). The production of a strong Th-1 type cytokine (IFN-γ) was induced while Th-2 type (IL-4) was suppressed by BPA treatment. These were consistent with RT-PCR results of transcription factor GATA-3 and IRF-1. These findings suggested that stimulation of prolactin production by estrogenic effects of BPA would affect cytokine profiles, and lead to imbalanced cellular immune response. In addition, we could speculate that prolactin and cytokine is important mediator involved in network between neuroendocrine and immune system by BPA.

title: Plant-originated glycoprotein (36 kDa) suppresses interleukin-4 and -10 in bisphenol A–stimulated primary cultured mouse lymphocytes
abstract: Bisphenol A (BPA) is one of the estrogen mimic environmental hormones and a chemical used for the wrapping foods, toy products for children, biomedical equipment, and machines. It can exert toxic effects, such as occurring allergy-related diseases. This study demonstrates that glycoprotein isolated from Rhus verniciflua Stokes (RVS glycoprotein) has an inhibitory activity of T-helper type 2 (Th2) cytokines [Interleukin (IL)-4 and -10]. First, it was shown that RVS glycoprotein inhibits the proliferation of lymphocytes and scavenges intracellular reactive oxygen species (ROS). Then, the activities of mitogen-activated protein kinase (MAPK), GATA-binding protein-3 (GATA-3), t-box expressed in T-cells (T-bet), and Th2 cell-related cytokine (IL-4 and -10) were evaluated in BPA (50 μM)-stimulated primary cultured mouse lymphocytes, using immunoblot analysis and reverse-transcription polymerase chain reaction (RT-PCR). The results showed that the RVS glycoprotein (50 μg/mL) inhibited the proliferation of lymphocytes, intracellular ROS, and activity of p38 MAPK dose dependently. In the transcriptional factors for the oriented differentiation of T-helper cells, the RVS glycoprotein (50 μg/mL) significantly suppressed the GATA-3, whereas it enhanced T-bet. Also, the RVS glycoprotein (100 μg/mL) significantly attenuated Th2-related cytokines (IL-4 and -10). Taken together, the results obtained from this study suggest that the RVS glycoprotein may help in preventing allergy-related immune dysfunction, such as that produced by BPA.

title: Estrogen receptor α in mouse splenic lymphocytes: possible involvement in immunity
abstract: To elucidate relevance of estrogens to immune responses, we investigated whether estrogen receptor α (ERα) exists in mouse splenic B cells and T cells and the effect of 17β-estradiol and endocrine disrupting chemicals (EDCs) on lymphocyte mitogenesis. ERα was identified in both male and female mouse splenic cells using RT-PCR. Crude splenic cells were stained with anti-ER antibody, and the distribution of ERα in the splenic B cells and part of the splenic T cells was confirmed by flow cytometry. 17β-Estradiol inhibited B cell mitogenesis at the concentration of 10−8 M and T cell mitogenesis at the concentration of 10−6 M. Some EDCs, diethylstilbestrol, bisphenol A, p-nonylphenol and di-2-ethylhexylphthalate, suppressed lymphocyte mitogenesis at the concentration of 10−6–10−5 M. We therefore suggest that estrogen may suppress lymphocyte mitogenesis through ERα in B and T cells.

title: Orally Administered Bisphenol A Disturbed Antigen Specific Immunoresponses in the Naïve Condition
abstract: Bisphenol A [2,2-bis(4-hydoxyphenyl)propane; BPA] is an endocrine disrupter widely used in polycarbonate plastics and epoxy resins. We investigated the effects of orally administered BPA on antigen-specific responses of the naïve immune system. BPA was orally administered to T cell receptor transgenic mice, and the antigen-specific responses of immune cells were investigated. Administered BPA moderately reduced interleukin (IL)-2, 4, and interferon (IFN)-γ secretion and increases in IgA and IgG2a production. Additionally, it was found that orally administered BPA increased antigen-specific IFN-γ production of T cells and modified whole antigen presenting cells (APCs) to suppress antigen-specific cytokine production from T cells. These findings suggest that BPA can augment the Th1-type responses of naïve immune systems, though the bioavailability of orally administered BPA was low in our experiments.

title: In vitro molecular mechanisms of bisphenol A action.
abstract: Bisphenol A (BPA, 2,2-bis (4-hydroxyphenyl) propane; CAS# 80-05-7) is a chemical used primarily in the manufacture of polycarbonate plastic, epoxy resins and as a non-polymer additive to other plastics. Recent evidence has demonstrated that human and wildlife populations are exposed to levels of BPA which cause adverse reproductive and developmental effects in a number of different wildlife species and laboratory animal models. However, there are major uncertainties surrounding the spectrum of BPA's mechanisms of action, the tissue-specific impacts of exposures, and the critical windows of susceptibility during which target tissues are sensitive to BPA exposures. As a foundation to address some of those uncertainties, this review was prepared by the "In vitro" expert sub-panel assembled during the "Bisphenol A: An Examination of the Relevance of Ecological, In vitro and Laboratory Animal Studies for Assessing Risks to Human Health" workshop held in Chapel Hill, NC, Nov 28-29, 2006. The specific charge of this expert panel was to review and assess the strength of the published literature pertaining to the mechanisms of BPA action. The resulting document is a detailed review of published studies that have focused on the mechanistic basis of BPA action in diverse experimental models and an assessment of the strength of the evidence regarding the published BPA research.

title: Immunotoxicity of bisphenol S and F are similar to that of bisphenol A during zebrafish early development.
abstract: Bisphenol S (BPS) and bisphenol F (BPF) have been increasingly used as alternatives to bisphenol A (BPA) owing to health concerns. The present study aims to evaluate the impact of these two BPA analogs on oxidative stress and the immune system during zebrafish embryonic and larval development. Environmentally relevant levels of BPS and BPF exposure could increase reactive oxygen species (ROS) content, nitric oxide (NO) content, nitric oxide synthase (NOS) activity, and the expression of immunity-related genes in concentration dependent manners during the early developmental stages in zebrafish. At a concentration of 100 μg/L, BPS and BPF showed similar effects on the immune toxicity of zebrafish as that of BPA. Moreover, BPS and BPF induced both erα and nf-κb expression, and antagonists of estrogen receptor and NF-κB blocked the effects on immunity-related gene expression, providing evidence that the two pathways mediate the actions of BPS and BPF on fish immune response and functions. Thus we conclude that the presence of BPS and BPF in the environment, similar to BPA, may also pose risks to ecosystem and human health and cannot be widely used without limitations and precautions.

title: Immunotoxicity of bisphenol A to Carassius auratus lymphocytes and macrophages following in vitro exposure.
abstract: Bisphenol A (BPA) is the monomer component of polycarbonate plastics and classified as an endocrine disrupting chemical (EDC). The reproductive toxicity of BPA has been extensively studied in mammals; however, relatively little information is available on the immunotoxic responses of fish to BPA. In this study, we investigated the effects of BPA on the immune functions of lymphocytes and macrophages in Carassius auratus. The effects of BPA were compared with those of two natural steroid hormones, estradiol and hydrocortisone. Proliferation of the two types of cells in response to PHA was measured using colorimetric MTT assay. Macrophage respiratory burst stimulated by Con A was measured using chemiluminescence assay. Results showed that BPA (0.054-5.4 mg/L), estradiol (0.0002-2.0 mg/L) and hydrocortisone (5-50 mg/L) significantly induced Carassius auratus lymphocyte proliferation while higher doses of hydrocortisone (500-5000 mg/L) appeared to be inhibitory. BPA (0.005-50 mg/L), estradiol (0.005-800 mg/L) and hydrocortisone (0.005-500 mg/L) markedly enhanced macrophage proliferation, whereas higher doses of BPA (500-1000 mg/L) appeared to inhibit cell proliferation. Furthermore, higher dosage of BPA (50 mg/L) and hydrocortisone (50 and 500 mg/L) suppressed the macrophages respiratory burst while estradiol is stimulative all the doses tested (0.05-500 mg/L). In conclusion, BPA could have immunotoxicity to Carassius auratus and functional changes of lymphocyte and macrophage in Carassius auratus may be different between low and high dosages.