Urinary bisphenol A concentrations are associated with abnormal liver function in the elderly: a repeated panel study

Bisphenol A (BPA) and Cardiovascular or Cardiometabolic Diseases

Bisphenol A (BPA; 4,4'-isopropylidenediphenol) is a well-known endocrine disruptor. Most human exposure to BPA occurs through the consumption of BPA-contaminated foods. Cardiovascular or cardiometabolic diseases such as diabetes, obesity, hypertension, acute kidney disease, chronic kidney disease, and heart failure are the leading causes of death worldwide. Positive associations have been reported between blood or urinary BPA levels and cardiovascular or cardiometabolic diseases. BPA also induces disorders or dysfunctions in the tissues associated with these diseases through various cell signaling pathways. This review highlights the literature elucidating the relationship between BPA and various cardiovascular or cardiometabolic diseases and the potential mechanisms underlying BPA-mediated disorders or dysfunctions in tissues such as blood vessels, skeletal muscle, adipose tissue, liver, pancreas, kidney, and heart that are associated with these diseases.

Natural Products in Mitigation of Bisphenol A Toxicity: Future Therapeutic Use

Bisphenol A (BPA) is a ubiquitous environmental toxin with deleterious endocrine-disrupting effects. It is widely used in producing epoxy resins, polycarbonate plastics, and polyvinyl chloride plastics. Human beings are regularly exposed to BPA through inhalation, ingestion, and topical absorption routes. The prevalence of BPA exposure has considerably increased over the past decades. Previous research studies have found a plethora of evidence of BPA’s harmful effects. Interestingly, even at a lower concentration, this industrial product was found to be harmful at cellular and tissue levels, affecting various body functions. A noble and possible treatment could be made plausible by using natural products (NPs). In this review, we highlight existing experimental evidence of NPs against BPA exposure-induced adverse effects, which involve the body’s reproductive, neurological, hepatic, renal, cardiovascular, and endocrine systems. The review also focuses on the targeted signaling pathways of NPs involved in BPA-induced toxicity. Although potential molecular mechanisms underlying BPA-induced toxicity have been investigated, there is currently no specific targeted treatment for BPA-induced toxicity. Hence, natural products could be considered for future therapeutic use against adverse and harmful effects of BPA exposure.

Tangeretin ameliorates bisphenol induced hepatocyte injury by inhibiting inflammation and oxidative stress

Bisphenol A (BPA) is an industrial toxicant that can potentially damage the liver. Tangeretin (TGN) is a natural flavonoid that displays various pharmacological activities. This experiment was carried out to evaluate the protective effects of TGN against BPA-induced hepatic impairment in the male albino rat. Twenty-four male albino rats were equally divided into four different groups: control, BPA (100 mg/kg), BPA + TGN (100 mg/kg + 50 mg/kg) and TGN (50 mg/kg). BPA exposure significantly decreased the activities of catalase (CAT), superoxidase dismutase (SOD), peroxidase (POD), glutathione reductase (GSR), glutathione S-transferase (GST), and glutathione (GSH) content while substantially increasing the thiobarbituric acid reactive substances (TBARS) and hydrogen peroxide (H₂O₂) levels. A substantial increase in the levels of alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST) was also observed in BPA treated rats. Moreover, BPA significantly increased the inflammatory markers, including tumor necrosis factor-α (TNF-α), nuclear factor kappa-B (NF-κB), Interleukin-6 (IL-6), Interleukin-1β (IL-1β)levels, cyclooxygenase-2 (COX-2) activity, and histopathological damages. However, co-treatment with TGN efficiently minimized the BPA-induced biochemical, inflammatory, and histopathological impairments in rat liver. The present study shows that TNG has significant potential to avert BPA-induced liver damage to its antioxidant and anti-inflammatory properties.

Association of endocrine disrupting chemicals levels in serum, environmental risk factors, and hepatic function among 5- to 14-year-old children

Endocrine-disrupting chemicals (EDCs) might increase the risk of childhood diseases by disrupting hormone-mediated processes that are critical for growth and development during childhood, however, the association among the exposure level of EDCs such as Nonylphenol (NP), Bisphenol A (BPA), Dimethyl phthalate (DMP) in children and environmental risk factors, as well as hepatic function has not been elaborated. This study aimed to discuss this interesting relationship among NP, BPA, DMP concentrations in serum, environmental risk factors, hepatic function of 5- to 14-year-old children in industrial zone, residential zone and suburb in northern district of Guizhou Province, China. In Zunyi city, 1006 children participated in cross-sectional health assessments from July to August 2018, and their parents completed identical questionnaires on the environmental risk factors of EDCs exposure to mothers and children. Serum NP, BPA and DMP concentrations were measured by high performance liquid chromatography (HPLC). Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), AST/ALT, total bilirubin (TBIL), direct bilirubin (DBIL) and indirect bilirubin (IBIL) were detected with automatic biochemical analyzer. The median concentrations of serum NP, BPA, and DMP in the participants were 45.85 ng/mL, 26.31 ng/mL and 31.62 ng/mL, respectively, which were higher than the environmental concentration limits of the U.S. National Environmental Protection Agency (EPA). Hair gels used during pregnancy, types of domestic drinking water, nail polish and cosmetics used by children were significantly positive correlated with serum NP concentration (P < 0.05). Gender, feeding pattern, plastic water cup used during pregnancy, hair spray and perfume use for children, duration of children birth, materials for baby bottle or cup and ways to plastic products were significantly positively correlated with serum BPA concentration (P < 0.05). Gender, perms used during pregnancy, hair spray and perfume use for children, using plastic lunch box during pregnancy, duration of children birth, exposure to pesticides, parents' occupations were significantly positively correlated with serum DMP concentrations (P < 0.05). Serum NP (β = 0.296, P = 0.036) and DMP (β = 0.316, P = 0.026) concentrations and TBIL level were significantly positively correlated. Serum NP concentration and the levels of IBIL (β = 0.382, P = 0.006) are significantly positively correlated. Cosmetics used during pregnancy significantly increased AST level (β = 2.641, P = 0.021). There was a positive correlation between the frequency of hair spray and perfume use for children and the AST (β = 4.241, P = 0.022). NP, BPA and DMP, which were commonly detected in the serum of children aged 5-14 years old in Zunyi City, Northern Guizhou Province, China, were closely related to the environmental risk factors of exposure environment during pregnancy, infancy and school age. Exposure to NP, BPA and DMP would have negative effects on hepatic function, and these effects showed differences in gender and geographical location. Notably,The relationships were more evident in girls than in boys.

Role of Endocrine-Disrupting Chemicals in the Pathogenesis of Non-Alcoholic Fatty Liver Disease: A Comprehensive Review

Non-alcoholic fatty liver disease (NAFLD) is considered the most common liver disorder, affecting around 25% of the population worldwide. It is a complex disease spectrum, closely linked with other conditions such as obesity, insulin resistance, type 2 diabetes mellitus, and metabolic syndrome, which may increase liver-related mortality. In light of this, numerous efforts have been carried out in recent years in order to clarify its pathogenesis and create new prevention strategies. Currently, the essential role of environmental pollutants in NAFLD development is recognized. Particularly, endocrine-disrupting chemicals (EDCs) have a notable influence. EDCs can be classified as natural (phytoestrogens, genistein, and coumestrol) or synthetic, and the latter ones can be further subdivided into industrial (dioxins, polychlorinated biphenyls, and alkylphenols), agricultural (pesticides, insecticides, herbicides, and fungicides), residential (phthalates, polybrominated biphenyls, and bisphenol A), and pharmaceutical (parabens). Several experimental models have proposed a mechanism involving this group of substances with the disruption of hepatic metabolism, which promotes NAFLD. These include an imbalance between lipid influx/efflux in the liver, mitochondrial dysfunction, liver inflammation, and epigenetic reprogramming. It can be concluded that exposure to EDCs might play a crucial role in NAFLD initiation and evolution. However, further investigations supporting these effects in humans are required.

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

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

Modification of PARP4, XRCC3, and RAD51 Gene Polymorphisms on the Relation between Bisphenol A Exposure and Liver Abnormality

Repair genes may play critical roles in the relationships between environmental exposure and health outcomes. However, no evidence is available about the effect of repair gene polymorphisms on the relationship between bisphenol A (BPA) exposure and liver abnormality. Therefore, we evaluated the effect of nine genotyped polymorphisms in three repair genes, poly(ADP-ribose) polymerase family member 4 (PARP4), X-ray repair cross complementing 3 (XRCC3), and RAD51 recombinase (RAD51), on the relationship between BPA exposure and liver abnormality using repeated measures data for an elderly population. A significant association between BPA levels and liver abnormality was found only in elders with the PARP4 G-C-G haplotype, XRCC3 G-A-G haplotype, or RAD51 T-A-A haplotype (odds ratio (OR) = 2.16 and p = 0.0014 for PARP4; OR = 1.57 and p = 0.0249 for XRCC3; OR = 1.43 and p = 0.0422 for RAD51). Particularly, PARP4 and XRCC3 showed significant interactions with BPA exposure in relation to liver abnormality (p < 0.05 for both genes). These results indicate that PARP4, XRCC3, and RAD51 gene polymorphisms have modification effects on the relationship between BPA exposure and liver abnormality.

Autophagy role in environmental pollutants exposure

During the last decades, the potential harmfulness derived from the exposure to environmental pollutants has been largely demonstrated, with associated damages ranging from geno- and cyto-toxicity to tissue malfunction and alterations in organism physiology. Autophagy is an evolutionarily-conserved cellular mechanism essential for cellular homeostasis, which contributes to protect cells from a wide variety of intracellular and extracellular stressors. Due to its pivotal importance, its correct functioning is directly linked to cell, tissue and organismal fitness. Environmental pollutants, particularly industrial compounds, are able to impact autophagic flux, either by increasing it as a protective response, by blocking it, or by switching its protective role toward a pro-cell death mechanism. Thus, the understanding of the effects of chemicals exposure on autophagy has become highly relevant, offering new potential approaches for risk assessment, protection and preventive measures to counteract the detrimental effects of environmental pollutants on human health.

The adverse health effects of bisphenol A and related toxicity mechanisms

Bisphenol A (BPA) is an industrial component commonly used in synthesis of polycarbonate plastics, epoxy resin and other polymer materials. Due to its mass productions and widespread applications, the presence of BPA is ubiquitous in the environment. BPA can enter the body via different ways such as digestive tract, respiratory tract and dermal tract. As an endocrine disruptor, BPA has estrogen-like and anti-androgen effects causing damages to different tissues and organs, including reproductive system, immune system and neuroendocrine system, etc. Recently, it has been shown that BPA could induce carcinogenesis and mutagenesis in animal models. Here, the underlying mechanisms of BPA-induced multi-organ toxicity were well summarized, involving the receptor pathways, disruption of neuroendocrine system, inhibition of enzymes, modulation of immune and inflammatory responses, as well as genotoxic and epigenetic mechanisms. The aim of this review is to compile the available current research data regarding BPA and provide an overview of the current status of BPA exposure and relevant health effects covering reproductive, developmental, metabolic, immuno, respiratory, hepatic and renal toxicity and carcinogenesis of BPA. This review provides comprehensive data of BPA toxicity on human health and related mechanisms. We also identify any missing data which should be addressed by further studies.

Developmental programming: Sex-specific programming of growth upon prenatal bisphenol A exposure

In both human and animals, in utero exposure to bisphenol A (BPA), an endocrine-disrupting chemical used in the production of plastics and epoxy resins, has been shown to affect offspring reproductive and metabolic health during adult life. We hypothesized that the effect of prenatal exposure to environmentally relevant doses of BPA will be evident during fetal organogenesis and fetal/postnatal growth trajectory. Pregnant ewes were administered BPA subcutaneously from 30 to 90 days of gestation (term 147 days). Fetal organ weight, anthropometric measures, maternal/fetal hormones and postnatal growth trajectory were measured in both sexes. Gestational BPA administration resulted in higher accumulation in male than female fetuses only at fetal day 65, with minimal impact on fetal/maternal steroid milieu in both sexes at both time points. BPA-treated male fetuses were heavier than BPA-treated female fetuses at fetal day 90 whereas this sex difference was not evident in the control group. At the organ level, liver weight was reduced in prenatal BPA-treated female fetuses, while heart and thyroid gland weights were increased in BPA-treated male fetuses relative to their sex-matched control groups. Prenatal BPA treatment also altered the postnatal growth trajectory in a sex-specific manner. Males grew slower during the early postnatal period and caught up later. Females, in contrast, demonstrated the opposite growth trend. Prenatal BPA-induced changes in fetal organ differentiation and early life growth strongly implicate translational relevance of in utero contributions to reproductive and metabolic defects previously reported in adult female offspring.

A prospective cohort study of the association between bisphenol A exposure and the serum levels of liver enzymes in children

BACKGROUND

Bisphenol A (BPA) is an endocrine disrupter that acts in an estrogen-like manner. Few studies have investigated the association between urinary BPA concentrations and adverse liver function. Additionally, most studies were cross-sectional in nature and included only adults.

OBJECTIVES

We evaluated BPA exposure levels and prospectively explored the association between BPA exposure and liver function in children.

METHODS

Data were retrieved from the ongoing prospective Ewha Birth and Growth Cohort Study. Urinary BPA concentrations were measured in 164 children at 3-5 and 7-9 years of age. At each visit, fasting blood and urine samples were collected, and questionnaires were completed. The associations between the BPA concentrations at these ages and the serum levels of liver enzymes measured at 10-13 years of age were analyzed (n = 113). Multiple regression analysis was performed with adjustment for covariates. We also explored whether the BPA level exhibited dose-response relationships with liver enzyme levels.

RESULTS

The median urinary BPA concentrations were 0.76μg/g creatinine at 3-5 years and 0.61μg/g creatinine at 7-9 years of age. The urinary BPA concentrations at the two ages were correlated significantly (r = 0.23, p < 0.01). The urinary BPA concentrations at 7-9 years, but not that at 3-5 years, was associated significantly with the serum levels of liver enzymes at 10-13 years of age (p < 0.05). Those in the top tertile of urinary BPA concentration had higher levels of liver enzymes than did others. After adjustment for covariates, dose-response relationships of the BPA level with liver enzyme levels were evident at 7-9 years, but not at 3-5 years. Notably, the effect size was larger and the dose-response relationships were more evident in boys than in girls.

CONCLUSIONS

Exposure of children to even low doses of BPA may adversely affect later liver function.

Bisphenol A induces COX-2 through the mitogen-activated protein kinase pathway and is associated with levels of inflammation-related markers in elderly populations

Bisphenol A (BPA) is a well-known endocrine-disrupting chemical, and it is one of the highest volume chemicals produced worldwide. Even though several in vivo and in vitro studies showed positive associations of BPA exposure with pro-inflammatory cytokines such as tumor necrosis factor-α and interleukin (IL)-6, the mechanism by which BPA induces inflammation is unclear. We investigated the mechanism by which BPA induces inflammation (expression of inflammation-related genes, changes in oxidative stress, and cell proliferation and migration) and evaluated the effect of BPA exposure on inflammation-related markers in epidemiologic studies using repeat urine and serum samples from elderly subjects. BPA induced COX-2 expression via nuclear translocation of NF-κB and activation of mitogen-activated protein kinase (MAPK) by phosphorylation of ERK1/2 and enhanced the migration of lung cancer A549 and breast cancer MDAMB-231 cells. In two epidemiologic studies, we detected associations of BPA with six inflammation-related markers (WBC, CRP, IL-10, ALT, AST, and γ-GTP levels). Our findings probably suggest that BPA exposure induces inflammation and exacerbates tumorigenesis.

Dysregulated Autophagy in Hepatocytes Promotes Bisphenol A-Induced Hepatic Lipid Accumulation in Male Mice

Accumulating evidence suggests that bisphenol A (BPA) exposure is associated with nonalcoholic fatty liver disease. Disruption of autophagy causes lipid accumulation in hepatocytes. Whether and how BPA regulates autophagy remains to be explored. We investigated the effect of BPA on autophagy in hepatocytes and examined the influence of BPA-regulated autophagy on hepatic lipid accumulation. Male CD1 mice were treated with BPA for 8 weeks, followed by histological and biochemical evaluation of liver lipids and autophagy. Also, the effects of BPA on autophagy and hepatic lipid accumulation were examined in primary hepatocytes and HepG2 cells. Lipid content in HepG2 cells and/or primary hepatocytes was increased obviously after BPA exposure. In addition, BPA exposure caused accumulation of autophagosomes in HepG2 cells and enhanced colocalization of Bodipy 493/503 with microtubule associated protein light-chain 3. These changes were accompanied with increased expression levels of p-mammalian target of rapamycin, p-p70S6 kinase, p-ULK1 and decreased expression levels of Atg5. BPA exposure also downregulated the expression of cathepsin L and decreased cytoplasmic retention of acridine orange in HepG2 cells. The impaired autophagic degradation was further evidenced by increased levels of p62 in BPA-treated HepG2 cells. At the whole animal level, BPA treatment induced lipid accumulation in livers of male CD1 mice, which was accompanied with changes in hepatic autophagy-related proteins. Moreover, induction of autophagy by Torin1 protected against BPA-induced lipid accumulation whereas suppression of autophagy by chloroquine exacerbated BPA-induced lipid accumulation in HepG2 cells. BPA dysregulates autophagy in hepatocytes, which is linked to BPA-induced hepatic lipid accumulation.

Metabolism disrupting chemicals and metabolic disorders

The recent epidemics of metabolic diseases, obesity, type 2 diabetes(T2D), liver lipid disorders and metabolic syndrome have largely been attributed to genetic background and changes in diet, exercise and aging. However, there is now considerable evidence that other environmental factors may contribute to the rapid increase in the incidence of these metabolic diseases. This review will examine changes to the incidence of obesity, T2D and non-alcoholic fatty liver disease (NAFLD), the contribution of genetics to these disorders and describe the role of the endocrine system in these metabolic disorders. It will then specifically focus on the role of endocrine disrupting chemicals (EDCs) in the etiology of obesity, T2D and NAFLD while finally integrating the information on EDCs on multiple metabolic disorders that could lead to metabolic syndrome. We will specifically examine evidence linking EDC exposures during critical periods of development with metabolic diseases that manifest later in life and across generations.

Increase of urinary malondialdehyde level by bisphenol A exposure: a longitudinal panel study

BACKGROUND

To verify oxidative stress as a possible mechanism that establishes a relationship between exposure to bisphenol A (BPA) and adverse health outcomes in the elderly Korean population, we evaluated the relation between visit-to-visit variations in urinary BPA and oxidative stress biomarker.

METHODS

To assess the relation between BPA and urinary malondialdehyde (MDA) as an oxidative stress biomarker, we used a mixed effect model after controlling for age, sex, BMI, drinking status, exercise, urinary cotinine level, PM₁₀ on lag day 2, and mean temperature and dew point on the day. The relation between exposure to BPA and MDA level by sex of participants and polymorphisms of oxidative stress-related genes (COX2, EPHX1, HSP70-hom, PON1, eNOS, CAT, DRD2, SOD2, and MPO) was also evaluated.

RESULTS

A significant association was found for BPA with MDA in both male and female elderly participants (male, β = 0.19 and p = 0.0003; female, β = 0.18 and p < .0001; and total, β = 0.18 and p < .0001). Furthermore, the association of BPA with MDA was found regardless of any genotype of the nine oxidative stress-related genes.

CONCLUSIONS

The results of our study suggest a strong association of BPA with oxidative stress, not related with sex and oxidative stress-related gene polymorphisms.

Risk assessment based on urinary bisphenol A levels in the general Korean population

Bisphenol A (BPA) is a high-volume industrial chemical used in the global production of polycarbonate plastics and epoxy resins, which are used in food and drink containers, such as tableware (plates and mugs). Due to its broad applications, BPA has been detected in human blood, urine and breast milk as well as environmental substances, including water, indoor and outdoor air, and dust. Indeed, exposure to high concentrations of BPA can result in a variety of harmful effects, including reproductive toxicity, through a mechanism of endocrine disruption. Our comparison of reported BPA urinary concentrations among different countries revealed that exposures in Korea may be higher than those in other Asian countries and North America, but lower than or similar to those in European countries. The current study included a total of 2044 eligible subjects of all ages. The subjects were evenly divided between males and females (48.58% and 51.42%, respectively). The geometric mean (GM) of pre-adjusted (adjusted) urinary BPA concentrations was 1.83μg/L (2.01μg/g creatinine) for subjects of all ages, and there was no statistically difference in BPA concentrations between males (1.90μg/L, 1.87μg/g creatinine) and females (1.76μg/L, 2.16μg/g creatinine). Multiple regression analysis revealed only one positive association between creatinine pre-adjusted urinary BPA concentration and age (β=-0.0868, p<0.001). The 95th percentile levels of 24-hour recall (HR), food frequency questionnaires (FFQ) and estimated daily intake (EDI) through urinary BPA concentrations were 0.14, 0.13, and 0.22μg/kg bw/day, respectively. According to the Ministry of Food and Drug Safety (MFDS), a tolerable daily intake (tDI) of 20μg/kg bw/day was established for BPA from the available toxicological data. Recently, the European Food Safety Authority (EFSA) established a temporary TDI of 4μg/kg bw/day based on current toxicological data. By comparing these TDIs with subjects' exposure, we conclude that there are no health concerns for any age group as a result of current levels of dietary exposure to BPA.

Modification of the association of bisphenol A with abnormal liver function by polymorphisms of oxidative stress-related genes

Some studies suggested oxidative stress as a possible mechanism for the relation between exposure to bisphenol A (BPA) and liver damage. Therefore, we evaluated modification of genetic polymorphisms of cyclooxygenase 2 (COX2 or PTGS2), epoxide hydrolase 1 (EPHX1), catalase (CAT), and superoxide dismutase 2 (SOD2 or MnSOD), which are oxidative stress-related genes, on the relation between exposure to BPA and liver function in the elderly. We assessed the association of visit-to-visit variations in BPA exposure with abnormal liver function by each genotype or haplotype after controlling for age, sex, BMI, alcohol consumption, exercise, urinary cotinine levels, and low density lipoprotein cholesterol using a GLIMMIX model. A significant association of BPA with abnormal liver function was observed only in participants with COX2 GG genotype at rs5277 (odds ratio (OR)=3.04 and p=0.0231), CAT genotype at rs769218 (OR=4.16 and p=0.0356), CAT CT genotype at rs769217 (OR=4.19 and p=0.0348), SOD2 TT genotype at rs4880 (OR=2.59 and p=0.0438), or SOD2 GG genotype at rs2758331 (OR=2.57 and p=0.0457). Moreover, we also found higher OR values in participants with a pair of G-G haplotypes for COX2 (OR=2.81 and p=0.0384), G-C-A haplotype for EPHX1 (OR=4.63 and p=0.0654), A-T haplotype for CAT (OR=4.48 and p=0.0245), or T-G-A haplotype for SOD2 (OR=2.91 and p=0.0491) compared with those with the other pair of haplotypes for each gene. Furthermore, the risk score composed of 4 risky pair of haplotypes showed interactive effect with BPA on abnormal liver function (p=0.0057). Our study results suggest that genetic polymorphisms of COX2, EPHX1, CAT, and SOD2 modify the association of BPA with liver function.

Biomonitoring of human exposures to chlorinated derivatives and structural analogs of bisphenol A

The high reactivity of bisphenol A (BPA) with disinfectant chlorine is evident in the instantaneous formation of chlorinated BPA derivatives (ClxBPA) in various environmental media that show increased estrogen-activity when compared with that of BPA. The documented health risks associated with BPA exposures have led to the gradual market entry of BPA structural analogs, such as bisphenol S (BPS), bisphenol F (BPF), bisphenol B (BPB), etc. A suite of exposure sources to ClxBPA and BPA analogs in the domestic environment is anticipated to drive the nature and range of halogenated BPA derivatives that can form when residual BPA comes in contact with disinfectant in tap water and/or consumer products. The primary objective of this review was to survey all available studies reporting biomonitoring protocols of ClxBPA and structural BPA analogs (BPS, BPF, BPB, etc.) in human matrices. Focus was paid on describing the analytical methodologies practiced for the analysis of ClxBPA and BPA analogs using hyphenated chromatography and mass spectrometry techniques, because current methodologies for human matrices are complex. During the last decade, an increasing number of ecotoxicological, cell-culture and animal-based and human studies dealing with ClxBPA exposure sources and routes of exposure, metabolism and toxicity have been published. Up to date findings indicated the association of ClxBPA with metabolic conditions, such as obesity, lipid accumulation, and type 2 diabetes mellitus, particularly in in-vitro and in-vivo studies. We critically discuss the limitations, research needs and future opportunities linked with the inclusion of ClxBPA and BPA analogs into exposure assessment protocols of relevant epidemiological studies.

Sex-dependent and body weight-dependent associations between environmental PAHs exposure and insulin resistance: Korean urban elderly panel

BACKGROUND

The prevalence of metabolic diseases rises rapidly with an ageing population. Recent studies suggest the potential involvement of environmental chemicals in insulin resistance (IR) that plays a core role in the development of metabolic diseases. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous components of outdoor and indoor air pollution. The influence of PAHs on IR may differ depending on sex and weight.

OBJECTIVES

We examined the association between exposure to environmental PAHs and IR in Korean urban elderly adults controlling for major risk factors that contribute to an increase in IR.

METHODS

Between 2008 and 2010, PAH metabolite levels (urinary 1-hydroxypyrene (1-OHP)) and the homoeostatic model assessment index (HOMA-IR) were repeatedly measured in 502 adults aged ≥60 years. Linear mixed effect models were fit to evaluate the associations of 1-OHP concentration with HOMA-IR. Subgroups were modelled by sex and weight.

RESULTS

After adjusting for sociodemographics, air pollution and metabolic disease status, the highest (vs lowest) quartile of 1-OHP was associated with an 0.57 (95% CI 0.10 to 1.04) increase in the HOMA-IR score (p trend=0.037). When stratified by sex, women presented a significantly dose-dependent trend of 1-OHP with HOMA-IR (p trend=0.013), whereas no association was observed in men (p trend=0.904). When further stratified by weight (body mass index ≥25 vs <25 kg/m(2)), a significant association was found only in overweight women (p trend=0.023).

CONCLUSIONS

Our results suggest that environmental exposure to PAHs is associated with increased IR in elderly adults and that the association may be limited to overweight women.

Bisphenol A Induces Apoptosis in Liver Cells through Induction of ROS

Oxidative stress mechanisms are involved in hepatotoxicity. The liver is reported to be affected by bisphenol A (BPA) in animals studies and has been also reported to possess hepatic toxicity. This study aimed to examine association between liver health status and the effects of BPA on the antioxidant defense systems and liver biomarkers. BPA (0, 2, 10, and 50 mg/kg) body weight was mixed in corn oil and intraperitoneally administered every forty-eight hours for 30 days in dose-dependent manner. There was no significant difference between the body weight and weight of rat liver in BPA-treated groups and control groups. The study results show that the levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) increased after exposure to BPA. However, the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX) were significantly (P<0.001, P<0.05, and P<0.001, resp.) decreased at 50 mg/kg dosage. Liver markers activities such as lactate dehydrogenase (LDH), glutamic-oxalacetic transaminase (GOT), and glutamic-pyruvic transaminase (GPT) were significantly increased, while γ-glutamyl transferase (γ-GT) activity was decreased. BPA exposure increased activity of liver biomarkers indicating liver hyperactivity. Analysis of the liver section provided essential evidence of liver apoptosis. Moreover, BPA may lead to induced toxic response of liver oxidative system.

Association between urinary levels of bisphenol A and its monochlorinated derivative and obesity

Population-based studies suggest the association between exposures to bisphenol A (BPA) and obesity. However, no human studies are available that link exposures to chlorinated derivatives of BPA with obesity biomarkers. The objective of this exploratory post hoc analysis of our cross-sectional study's dataset was to evaluate the association between urinary levels of BPA and monochlorinated BPA (mono-ClBPA) with body mass index (BMI) in a random sample of 223 adults (≥18 years) from the general population in Cyprus. Univariate analysis and multiple logistic regressions were performed for descriptive statistics and estimating odds ratio (OR) of above normal BMI, respectively. We observed a relatively weak positive association between urinary mono-ClBPA and BMI, such as (i) 76 ng g(-1) in participants with above normal BMI (≥25 kg m(-2)) versus 55 ng g(-1) in those with normal BMI (<25 kg m(-2)) (P for mean difference = 0.053) and (ii) higher percentage of participants with above normal BMI in the high urinary mono-ClBPA tertile (63% in tertile 3 and 57% in tertile 2 versus 50% in tertile 1, P for trend = 0.056). Similar tests of association between urinary BPA and BMI showed null outcome. A dichotomously-classified group analysis showed an increased odds ratio (OR) for higher BMI in the group with high creatinine-adjusted urinary levels of BPA and mono-ClBPA when compared with the participants group with low levels for both compounds [logistic model adjusted for gender and health status as potential confounders; adjusted OR (95% CI): 2.34 (1.10, 5.10), P = 0.027]. Measurements of both BPA and its trace chlorinated derivative in human matrices may be warranted for a comprehensive exposure assessment towards improving our understanding of their obesogenic effects.

Bisphenol A exposure and asthma development in school-age children: a longitudinal study

BACKGROUND

Although the effect of bisphenol A on various health outcomes has been extensively examined, few studies have investigated its effect on asthma.

OBJECTIVE

We hypothesized that exposure to bisphenol A in school-age children was associated with wheezing and asthma.

METHODS

Participants included 127 children aged 7-8 years without a previous asthma diagnosis in an elementary school in Seoul, Korea. Three surveys were conducted, each 2 years apart. Bisphenol A concentration was measured at the baseline survey, and PC20, which is defined as the methacholine concentration that induces a decrease in FEV1 of 20% from baseline, was measured at every survey. Associations between bisphenol A concentration at 7-8 years of age and wheezing, asthma, and PC20 at ages up to 11-12 years were examined using generalized estimating equations, a marginal Cox regression model, and a linear mixed model.

RESULTS

The log-transformed creatinine-adjusted urinary bisphenol A concentration at 7-8 years was positively associated with wheezing (odds ratio, 2.48; 95% confidence interval, 1.15-5.31; P = .02) and asthma (hazard ratio, 2.13; 95% confidence interval, 1.51-3.00; P<.001) at ages up to 11-12 years. Bisphenol A was also negatively associated with PC20 (ß = -2.33; P = .02). When stratified by sex, the association between bisphenol A and asthma remained significant only in girls (hazard ratio, 2.45; 95% confidence interval, 2.18-2.76; P<.001).

CONCLUSION

Increased urinary bisphenol A concentrations at 7-8 years old were positively associated with wheezing and asthma and negatively associated with PC20 at ages up to 11-12 years.

Bisphenol A exposure and associations with obesity among adults: a critical review

Objective

To review the literature on bisphenol A (BPA) exposure and obesity in human populations.

Design

Systematic review of the literature via searches of PubMed, EMBASE, Web of Science and reference lists for articles published to 1 August 2014.

Setting

China, Italy, Japan, Republic of Korea, Sweden, UK, USA.

Subjects

Adults (≥18 years).

Results

Eighteen articles were identified and included in the review. Twelve studies included secondary evaluations of BPA exposure and BMI, and six studies evaluated body composition as the primary outcome. All analyses were cross-sectional and no study included in the review received a positive quality rating (twelve negative, six neutral). Eight studies observed a statistically significant positive association between urinary or serum BPA levels and BMI, and ten studies observed no association. Studies where BMI was a primary outcome and studies of neutral quality were more likely to observe an association.

Conclusions

Study results are conflicting and significant methodological issues limit the ability to draw conclusions from these studies. Prospective studies that measure BPA exposure and changes in body weight and composition are needed to establish temporality, causality and the direction of any observed associations.

The Potential Roles of Bisphenol A (BPA) Pathogenesis in Autoimmunity

Bisphenol A (BPA) is a monomer found in commonly used consumer plastic goods. Although much attention in recent years has been placed on BPA's impact as an endocrine disruptor, it also appears to activate many immune pathways involved in both autoimmune disease development and autoimmune reactivity provocation. The current scientific literature is void of research papers linking BPA directly to human or animal onset of autoimmunity. This paper explores the impact of BPA on immune reactivity and the potential roles these mechanisms may have on the development or provocation of autoimmune diseases. Potential mechanisms by which BPA may be a contributing risk factor to autoimmune disease development and progression include its impact on hyperprolactinemia, estrogenic immune signaling, cytochrome P450 enzyme disruption, immune signal transduction pathway alteration, cytokine polarization, aryl hydrocarbon activation of Th-17 receptors, molecular mimicry, macrophage activation, lipopolysaccharide activation, and immunoglobulin pathophysiology. In this paper a review of these known autoimmune triggering mechanisms will be correlated with BPA exposure, thereby suggesting that BPA has a role in the pathogenesis of autoimmunity.