Exposure to Bisphenol a and Gender Differences: From Rodents to Humans Evidences and Hypothesis about the Health Effects

Plasma bisphenol a and phthalate levels in children with cerebral palsy: a case-control study

The case-control study aimed to evaluate potential sources of exposure and the plasma concentrations of bisphenol A (BPA) and phthalates in prepubertal children having cerebral palsy (CP) and healthy control. Blood samples of 68 CP and 70 controls were analyzed for BPA, di-(2-ethylhexyl)-phthalate (DEHP), mono-(2-ethylhexyl)-phthalate (MEHP), and dibutyl phthalate (DBP). BPA and DBP levels were similar in groups. The median DEHP and MEHP levels of the children with CP were significantly lower than those of the controls (p = 0.035, p < 0.001, respectively). Exposure to plastic food containers/bags, personal care hygiene products, household cleaners, wood/coal stove heating, and city water supplies were associated with increased odds of higher BPA and phthalate levels in children with CP. In conclusion, potential exposure sources for BPA and phthalates differ in children with CP and healthy controls, and children with CP are not exposed to higher levels of BPA and phthalates.

Exposure assessment to bisphenol A (BPA) and its analogues bisphenol S (BPS) and bisphenol F (BPF) in wild boars by hair analysis

Bisphenols are widely used in various branches of industry for the production of plastics. They penetrate to the natural environment and thus living organisms. As endocrine disruptors, bisphenols have adverse effects on various internal organs and systems. Contrary to humans, the knowledge of the exposure of wild terrestrial mammals to bisphenols is extremely limited. Therefore, this study for the first time assessed the exposure level of wild boars to three bisphenols commonly used in industry (i.e. bisphenol A - BPA, bisphenol S - BPS and bisphenol F - BPF) using hair sample analysis in liquid chromatography-mass spectrometry (LC-MS). The presence of BPA and/or BPS has been noted in the samples collected from >80 % of animals included in the study (n = 54), while the presence of BPF was not found in any sample. At least one of the bisphenols was present in every sample tested. Mean concentrations of BPA and BPS in the hair of wild boars were 151.40 ± 135.10 pg/mg dry weight (dw.) and 29.40 ± 36.97 pg./mg dw, respectively. Concentrations of BPA and BPS in females were statistically higher than in males (p < 0.05). Moreover, statistically significantly higher concentration levels of BPA (and not BPS) in the areas with higher degree of industrialization and higher human population density were also found. This is the first study concerning the use of hair samples to assess the exposure of wild terrestrial mammals to bisphenols. The obtained results show that an analysis of the hair may be a useful tool of biomonitoring bisphenols in wild animals. The presence of BPA and BPS in wild boar hair in relatively high concentration also suggests that these substances may have an influence on the health status not only in humans and aquatic animals, but also in wild terrestrial mammals. However, many aspects connected with this issue are not clear and require further study.

Exploring aryl hydrocarbon receptor (AhR) as a target for Bisphenol-A (BPA)-induced pancreatic islet toxicity and impaired glucose homeostasis: Protective efficacy of ethanol extract of Centella asiatica

The estrogenic impact of Bisphenol-A (BPA), a widely recognized endocrine disruptor, causes disruption of pancreatic β-cell function through estrogen receptors (ERs). While BPA's binding affinity for ERs is significantly lower than that of its natural counterpart, estrogen, recent observations of BPA's affinity for aryl hydrocarbon receptor (AhR) in specific cellular contexts have sparked a specific question: does AhR play a role in BPA's toxicological effects within the endocrine pancreas? To explore this question, we investigated BPA's (10 and 100 μg/ kg body weight/day for 21 days) potential to activate AhR within pancreatic islets and assessed the protective role of ethanol extract of Centella asiatica (CA) (200 and 400 mg/kg body weight/day for 21 days) against BPA-mediated toxicity in mouse model. Our results indicate that BPA effectively triggers the activation of AhR and modulates its target genes within pancreatic islets. In contrast, CA activates AhR but directs downstream pathways differentially and activates Nrf2. Additionally, CA was observed to counteract the disruption caused by BPA in glucose homeostasis and insulin sensitivity. Furthermore, BPA-induced oxidative stress and exaggerated production of proinflammatory cytokines were effectively counteracted by CA supplementation. In summary, our study suggests that CA influenced AhR signaling to mitigate the disrupted pancreatic endocrine function in BPA exposed mice. By shedding light on how BPA interacts with AhR, our research provides valuable insights into the mechanisms involved in the diabetogenic actions of BPA.

Activation of NLRP3 Inflammasome in Liver of Long Evans Lactating Rats and Its Perinatal Effects in the Offspring after Bisphenol F Exposure

The liver is the organ responsible for the metabolism and detoxification of BPF, the BPA analogue that is replacing it in plastic-based products. It is not known whether BPF can trigger inflammatory responses via the NLRP3 inflammasome, which plays a major role in the development of liver disease. The aim of this study was to evaluate nitrosative stress species (RNS) and NLRP3 inflammasome activation in the liver of lactating dams after BPF exposure. Moreover, it was studied whether this effect could also be observed in the liver of female and male offspring at postnatal day 6 (PND6). 36 Long Evans rats were randomly distributed according to oral treatment into three groups: Control, BPF-low dose (LBPF; 0.0365 mg/kg b.w./day) group and BPF-high dose (HBPF; 3.65 mg/kg b.w./day) group. The levels of nitrosative stress-inducing proteins (eNOS, iNOS, HO-1d), NLRP3 inflammasome components (NLRP3, PyCARD, CASP1) and proinflammatory cytokines (IL-1β, IL-18, IFN-γ and TNF-α) were measured by gene and protein expression in the liver of lactating dams and in female and male PND6 offspring. Lactating dams treated with LBPF showed a significant increase in iNOS and HO-1d, activation of NLRP3 components (NLRP3, PyCARD, CASP1) and promoted the release of proinflammatory cytokines such as IL-1β, IL-18, IFN-γ and TNF-α. Similar effects were found in female and male PND6 offspring after perinatal exposure. LBPF oral administration and perinatal exposure caused an increase of nitrosative stress markers and proinflammatory cytokines. Also, NLRP3 inflammasome activation was significantly increased in in the liver of lactating dams and PND6 offspring.

Oxidative stress increases in liver of lactating rats after BPF-low-dose exposure: perinatal effects in the offspring

Bisphenol F (BPF) is replacing Bisphenol A (BPA) in the manufacture of products due to endocrine-disrupting effects. BPF monomers can also be released into the environment and enter the food chain, resulting in human exposure to low doses. Since bisphenols are primarily metabolized by the liver, this organ is more vulnerable to lower doses of bisphenols than others. Exposure during prenatal development may increase the risk of diseases in adulthood. The aim was to evaluate whether BPF administration could generate oxidative stress in liver of lactating rats, and whether these effects may be also observed in female and male postnatal day 6 (PND6) offspring. Long Evans rats received oral treatment: Control, BPF-low-dose (LBPF) 0.0365 mg/kg b.w./day, and BPF-high-dose (HBPF) 3.65 mg/kg b.w./day. The levels of antioxidant enzymes (CAT, SOD, GR, GPx and GST), glutathione system (GSH, GSSG) and lipid damage markers (MDA, LPO) were measured using colorimetric methods in liver of both lactating dams and in PND6 offspring. Mean values were analyzed using Prism-7. LBPF affected liver defense mechanisms (antioxidant enzymes and glutathione system), increasing ROS levels and producing lipid peroxidation in lactating dams. Similar effects were found in female and male PND6 offspring as a consequence of perinatal exposure.

Kisspeptin as potential biomarker of environmental chemical mixture effect on reproductive hormone profile: A pilot study in adolescent males

BACKGROUND

Kisspeptin has been proposed as an effect biomarker to understand the mechanisms by which some environmental chemicals adversely affect the human reproductive system.

OBJECTIVE

To ascertain whether kisspeptin serum protein and DNA methylation levels are associated with exposure to several environmental chemicals (individually and as a mixture) and serum reproductive hormone levels in adolescent males.

METHODS

Three phenols (bisphenol A [BPA], methyl-paraben [MPB], and benzophenone-3 [BP3]); two toxic metals (arsenic and cadmium); and four metabolites of non-persistent pesticides, including insecticides (2-isopropyl-6-methyl-4-pyrimidinol [IMPy], malathion diacid [MDA], and dimethylcyclopropane carboxylic acid [DCCA]) and fungicides (ethylene thiourea [ETU]) were measured in first-morning urine samples of 133 adolescent males aged 15-17 years from the INMA-Granada cohort. In blood samples collected on the same day, KISS1 gene DNA methylation was measured at four CpGs from the Exon IV, as well as serum levels of kiss54 protein, total testosterone (T), estradiol (E₂), sex hormone binding-globulin, dehydroepiandrosterone sulfate, luteinizing hormone (LH), and follicle-stimulating hormone (FSH). Multiple linear regression and mixture (quantile g-computation) models were fit.

RESULTS

Urinary MDA and DCCA concentrations were associated with higher kiss54 levels [% change (95%CI) for each log-unit increase in concentration = 2.90 (0.32;5.56), and 1.93 (0.45,3.43), respectively]; IMPy with lower DNA methylation percentage at CpG1 and total CpGs [% change (95%CI) = -1.15 (-1.96;-0.33): -0.89 (-1.73;-0.01), respectively]; and BP3 and DCCA with lower total CpGs methylation [-0.53 (-1.04;-0.01) and - 0.69 (-1.37;-0.01), respectively]. The pesticide mixture and the whole chemical mixture were associated with higher kiss54 [% change (95%CI) = 9.09 (3.29;15.21) and 11.61 (3.96;19.82), respectively] and lower methylation levels at several CpGs. Additionally, serum kiss54 in the third tertile was associated with higher LH levels [% change (95%CI) = 28.69 (3.75-59.63)], and third-tertile CpG1, CpG2, and total CpG methylation percentages were associated with lower FSH and E₂.

CONCLUSION

The findings of the present study and the negative correlation between serum kiss54 levels and KISS1 DNA methylation percentages suggested that kisspeptin may be a promising effect biomarker.

Study of serum bisphenol-A and the mRNA of galactosidase beta 1 and tumor necrosis factor alpha in Egyptian patients with type 2 diabetes mellitus

Background

The pathogenesis of type 2 diabetes mellitus (T2DM) originates from multiple tissue defects. Environmental pollutants such like endocrine-disrupting chemicals (EDCs) have lately gotten special attention in triggering the metabolic abnormalities in relation to insulin resistance and T2DM. Bisphenol-A (BPA), which is one of the EDCs and simulates natural endogenous estrogens, has been implicated in the pathogenesis of several diseases, and, over the last decade, it has been revealed to have probable diabetogenic and obesogenic actions.

Aim

To study the environmental exposure of BPA by measuring its serum level together with the relative expression level of galactosidase beta 1 (GLB1), tumor necrosis alpha (TNF-α) mRNAs and malondialdehyde (MDA) as an oxidative stress marker determine the association of these markers with the glycemic control of Egyptian patients having T2DM.

Patients and methods

The present study was conducted on 90 participants categorized into group 1: 60 patients with T2DM and group 2: 30 subjects with normal glucose tolerance. Serum BPA levels were measured by enzyme-linked immunosorbent assay (ELISA) kit, and biochemical determinations were done by standard protocols. Because of the pro-oxidizing role of BPA, we measured serum level of malondialdehyde (MDA) as an oxidative stress marker. Peripheral blood mononuclear cells (PBMCs) were used for detecting the gene expression changes in GLB1 mRNA, a major marker of cellular senescence, and the mRNA of the proinflammatory cytokine, TNF-α.

Results

Serum levels of BPA in T2DM patients were significantly higher compared to their control group, and they were significantly and positively correlated to poor glycemic control and insulin resistance. T2DM patients showed significantly high serum MDA, mRNA levels of GLB1, and TNF-α. There was positive correlation between serum BPA levels and oxidative stress marker, senescence indicator, and inflammatory marker; however, there was no statistical significance for this correlation.

Conclusion

Our study demonstrates that there is a link between increased serum BPA levels, poor glycemic control, and insulin resistance in Egyptian patients with T2DM.

In Vitro Effects of Bisphenol Analogs on Immune Cells Activation and Th Differentiation

AIMS

Investigate the immunomodulatory effects of bisphenols in the THP-1 cell line and peripheral blood mononuclear cells in response to lipopolysaccharide (LPS) activation or to phorbol 12-myristate 13-acetate (PMA) and ionomycin.

BACKGROUND

We have previously demonstrated the usefulness of the evaluation of RACK1 expression as a link between endocrine disrupting activity and the immunotoxic effect of xenobiotics. We demonstrated that while BPA and BPAF reduced RACK1 expression, BPS was able to increase it.

OBJECTIVE

Bisphenol A (BPA) is one of the most commonly used chemicals in the manufacturing of polycarbonate plastics and plastic consumer products. Its endocrine disrupting (ED) potential and changes in European regulations have led to replacing BPA in many uses with structurally similar chemicals, like bisphenol AF (BPAF) and bisphenol S (BPS). However, emerging data indicated that bisphenol analogues may not be safer than BPA both in toxic effects and ED potential.

METHODS

THP-1 cell line and peripheral blood mononuclear cells were activated with lipopolysaccharide (LPS) or with phorbol 12-myristate 13-acetate (PMA) and ionomycin.

RESULTS

BPA and BPAF decreased LPS-induced expression of surface markers and the release of pro-inflammatory cytokines, while BPS increased LPS-induced expression of CD86 and cytokines. BPA, BPAF, and BPS affected PMA/ionomycin-induced T helper differentiation and cytokine release with gender-related alterations in some parameters investigated.

CONCLUSION

Data confirm that bisphenols can modulate immune cell differentiation and activation, further supporting their immunotoxic effects.

Association between bisphenol A exposure and thyroid dysfunction in adults: a systematic review and meta-analysis

The occurrence of thyroid dysfunction is affected by environmental factors, and BPA is a ubiquitous environmental pollutant with the potential to cause thyroid dysfunction. However, the limited epidemiological evidence shows an inconsistent association between BPA exposure and thyroid dysfunction. Therefore, the literature on the impact of BPA on thyroid was sorted and analyzed to study the relationship between BPA and adult thyroid function. The studies published on or before 23rd May 2022 from PubMed, Web of Science, and Scopus were collected analyzing the association between BPA exposure and the levels of thyroid hormones. The methodological quality of each study was assessed, the sensitivity analysis and subgroup analysis based on study population and gender were also performed, and publication bias was evaluated. A total of 2969 literature studies were retrieved. Based on inclusion and exclusion criteria, eleven studies were included. Our results showed that BPA concentration was negatively correlated with FT4 and TSH in males. Pooled correlation coefficients between BPA and FT4/TSH were -0.027 (95%CI = -0.030∼-0.024) and -0.058 (95%CI = -0.111∼-0.004). BPA concentration was positively correlated with FT4 in females, and the pooled correlation coefficient was 0.006 (95%CI = 0.003-0.008). The effects of BPA on thyroid hormone levels were significantly different between males and females. BPA may significantly decrease the levels of FT4 and TSH in males but increase the levels of FT4 in females. Considering the high heterogeneity among studies and the limited investigations into subgroups, the relationship between BPA exposure and thyroid dysfunction needs to be further investigated.

Unravelling sex-specific BPA toxicokinetics in children using a pediatric PBPK model

Bisphenol A (BPA) is a widely known endocrine disruptor (ED) found in many children's products such as toys, feeding utensils, and teething rings. Recent epidemiology association studies have shown postnatal BPA exposure resulted in developing various diseases such as diabetes, obesity, and neurodegeneration, etc., later in their lives. However, little is known about its sex-specific metabolism and consequently internal exposure. The aim of this study was to develop a sex-specific pediatric physiologically based pharmacokinetic model (PBPK) for BPA to compare their toxicokinetic differences. First, the published adult PBPK model was re-validated, and then this model was extended by interpolation to incorporate pediatric sex specific physiological and biochemical parameters. We used both the classical body weight and ontogeny-based scaling approach to interpolate the metabolic process. Then, the pharmacokinetic attributes of the models using the two-scaling approach mentioned above were compared with adult model. Further, a sex-specific PBPK model with an ontogeny scaling approach was preferred to evaluate the pharmacokinetic differences. Moreover, this model was used to reconstruct the BPA exposure from two cohorts (Helix and PBAT Cohort) from 7 EU countries. The half-life of BPA was found to be almost the same in boys and girls at the same exposure levels. Our model estimated BPA children's exposure to be about 1500 times higher than the tolerable daily intake (TDI) recently set by European Food Safety Authority (EFSA) i.e., 0.04 ng/kg BW/day. The model demonstrated feasibility of extending the adult PBPK to sex-specific pediatric, thus investigate a gender-specific health risk assessment.

The Current Findings on the Impact of Prenatal BPA Exposure on Metabolic Parameters: In Vivo and Epidemiological Evidence

Metabolic syndrome (MS) is a multifactorial disease entity and is not fully understood. Growing evidence suggests that early exposure to bisphenol A (BPA) is a significant risk factor for the development of metabolic diseases. BPA is a monomer used in the manufacturing of polycarbonate plastics, thermal receipt paper, and epoxy resins. Owing to its widespread use, BPA has been detected in human fluids and tissues, including blood, placental breast milk, and follicular fluid. In the present review, we aimed to review the impact of prenatal exposure to different doses of BPA on metabolic parameters as determined by in vivo and epidemiological studies. The PubMed, Scopus, and Web of Science electronic databases were searched to identify articles published during a period of 15 years from 2006 to 2021, and 29 studies met the criteria. Most studies demonstrated that prenatal exposure to low BPA concentrations correlated with alterations in metabolic parameters in childhood and an increased risk of metabolic diseases, such as obesity and type 2 diabetes mellitus (T2DM), in adulthood. Therefore, prenatal exposure to low doses of BPA may be associated with an increased risk of obesity and T2DM in a sex-specific manner.

Sex-specific changes in oxidative stress parameters and longevity produced by Bisphenol F and S compared to Bisphenol A in Drosophila melanogaster

Female and male Drosophila melanogaster were exposed separately for seven days to Bisphenol A (BPA), Bisphenol F (BPF), and Bisphenol S (BPS) at concentrations of 0.25, 0.5, and 1 mM. We observed that males exposed to 0.5 and 1 mM BPS showed lower catalase (CAT) activity and higher superoxide dismutase (SOD) and reactive species (RS); CAT activity decreased for BPF 0.5 and 1 mM. Nevertheless, BPA 0.5 and 1 mM decreased CAT activity, increased RS and lipid peroxidation (LPO), and reduced mitochondrial viability. None of the bisphenols altered the cell viability of male flies, although BPA 0.5 and 1 mM reduced longevity. In female flies, BPA and BPS 0.5 and 1 mM increased RS and LPO levels and decreased CAT activity and glutathione-S-transferase (GST), which may have contributed to lower mitochondrial and cell viability. Furthermore, BPS decreased SOD activity at the 1 mM concentration, and BPA reduced the SOD activity at concentrations of 0.5 and 1 mM. In the BPF 1 mM group, there was a reduction in GST activity and an increase in RS and LPO levels. The toxicological effects were different between sexes, and BPA was more harmful than BPF and BPS in male flies. Thus, our findings showed that females were more susceptible to oxidative cell damage when exposed to BPA and BPS than to BPF, and daily exposure to BPA and BPS at all concentrations reduced female longevity, as well as in BPF 1 mM.

Triglyceride profiles are associated with subacute exposure to bisphenol A in healthy young adults

Conflicted results from previous epidemiological studies call for mechanistic evidence to associate exposure to bisphenol A (BPA) with cardiometabolic diseases. In this natural experiment among healthy travelers from Los Angeles (LA) to Beijing, we collected paired urine and blood samples before their departure, 6-8 weeks after their arrival to Beijing, and 4-7 weeks after their return to LA for the assessment of urinary BPA and lipidome in the serum fraction of blood, to study the effects of drastically changed BPA exposure on the lipid metabolism in relation to the development of cardiometabolic disorders. We used linear mixed-effects models with random intercepts for participant and phase to examine the associations between urinary BPA and serum lipidome. Among 744 lipid species from seven classes, triglyceride (TGs) species showed the strongest associations with BPA exposure. The elevation in BPA exposure was associated with increases in TGs with short carbon chains or few double bonds, and decreases in TGs with long carbon chains or many double bonds. A significant linear relationship was observed between BPA-associated TG changes and the number of carbons and double-bonds in the acyl chain. No modification effects of gender but of body mass index (BMI) were observed on the associations between BPA exposure and TGs. This interdisciplinary environmental research substantiated the cardiometabolic effects of BPA according to the perturbations of TG profiling.

Bisphenol A (BPA) Leading to Obesity and Cardiovascular Complications: A Compilation of Current In Vivo Study

BPA is one of the most common endocrine disruptors that is widely being manufactured daily nationwide. Although scientific evidence supports claims of negative effects of BPA on humans, there is also evidence suggesting that a low level of BPA is safe. However, numerous in vivo trials contraindicate with this claim and there is a high possibility of BPA exposure could lead to obesity. It has been speculated that this does not stop with the exposed subjects only, but may also cause transgenerational effects. Direct disruption of endocrine regulation, neuroimmune and signaling pathways, as well as gut microbiata, has been identified to be interrupted by BPA exposure, leading to overweight or obesity. In these instances, cardiovascular complications are one of the primary notable clinical signs. In regard to this claim, this review paper discusses the role of BPA on obesity in the perspective of endocrine disruptions and possible cardiovascular complications that may arise due to BPA. Thus, the aim of this review is to outline the changes in gut microbiota and neuroimmune or signaling mechanisms involved in obesity in relation to BPA. To identify potentially relevant articles, a depth search was done on the databases Nature, PubMed, Wiley Online Library, and Medline & Ovid from the past 5 years. According to Boolean operator guideline, selected keywords such as (1) BPA OR environmental chemical AND fat OR LDL OR obese AND transgenerational effects or phenocopy (2) Endocrine disruptors OR chemical AND lipodystrophy AND phenocopy (3) Lipid profile OR weight changes AND cardiovascular effect (4) BPA AND neuroimmune OR gene signaling, were used as search terms. Upon screening, 11 articles were finalized to be further reviewed and data extraction tables containing information on (1) the type of animal model (2) duration and dosage of BPA exposure (3) changes in the lipid profile or weight (4) genes, signaling mechanism, or any neuroimmune signal involved, and (5) transgenerational effects were created. In toto, the study indicates there are high chances of BPA exposure affecting lipid profile and gene associated with lipolysis, leading to obesity. Therefore, this scoping review recapitulates the possible effects of BPA that may lead to obesity with the evidence of current in vivo trials. The biomarkers, safety concerns, recommended dosage, and the impact of COVID-19 on BPA are also briefly described.

Urinary bisphenol concentrations and its association with metabolic disorders in the US and Korean populations

Bisphenol A (BPA) is a representative endocrine disrupting compound used in a vast array of consumer products, and are being frequently substituted by its analogues, bisphenol S (BPS) and bisphenol F (BPF). We aimed to examine the association between urinary bisphenol levels with obesity and lipid profiles in the general population to comprehensively evaluate its potential of metabolic disturbance. A representative sample of 1046 US adults from the National Health and Nutrition Examination Survey (2013-2016) and 3268 Korean adults from the Korean National Environmental Health Survey (2015-2017) was analyzed. We examined the exposure levels of bisphenols and determined their associations with obesity, high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) levels, and hypercholesterolemia prevalence through multiple linear, and binary/ordinal logistic regression models. In both populations, high BPA levels (lowest tertile vs. 2nd, 3rd tertiles) showed corresponding associations with lipid profile and obesity. BPA levels were associated with decreased HDL-C levels (Q3: β = -0.053, p = 0.08 (US); Q2: β = -0.030, p-0.03), increased TG levels (Q3: β = 0.121, p = 0.029 (US); Q3: β = 0.089, p = 0.021, and higher odds for obesity (Q3: OR = 1.58, 95% CI: 1.06, 2.35 (US); Q3: OR = 1.41, 95% CI: 1.11, 1.78). Higher BPS levels were positively associated with obesity status, especially in US men (Q2: OR = 1.84, 95% CI: 1.15, 2.96) and Korean women (Q3: OR = 1.27, 95% CI: 0.99, 1.64). A significant decrease in HDL-C (Q3: β = -0.088, p = 0.01) and elevated odds for obesity at higher BPF levels (Q3: OR = 1.60, 95% CI: 1.00, 2.56) was observed in US women. The findings of our study indicate that BPA and its analogues, BPS and BPF, are associated with lipid metabolism disorders in addition to obesity in adults. Given the increase in exposure to BPA alternatives, continuous biomonitoring, and further investigation of their health effects through prospective cohort studies are warranted.

Comparison of the renal effects of bisphenol A in mice with and without experimental diabetes. Role of sexual dimorphism

Bisphenol-A (BPA), a chemical -xenoestrogen- used in the production of the plastic lining of food and beverage containers, is present in the urine of almost the entire population. Recent studies have shown that BPA exposure is associated with podocytopathy, increased urinary albumin excretion (UAE), and hypertension. Since these changes are characteristic of early diabetic nephropathy (DN), we explored the renal effects of BPA and diabetes including the potential role of sexual dimorphism. Male and female mice were included in the following animals' groups: control mice (C), mice treated with 21.2 mg/kg of BPA in the drinking water (BPA), diabetic mice induced by streptozotocin (D), and D mice treated with BPA (D + BPA). Male mice form the D + BPA group died by the tenth week of the study due probably to hydro-electrolytic disturbances. Although BPA treated mice did not show an increase in serum creatinine, as observed in D and D + BPA groups, they displayed similar alteration to those of the D group, including increased in kidney damage biomarkers NGAL and KIM-1, UAE, hypertension, podocytopenia, apoptosis, collapsed glomeruli, as well as TGF-β, CHOP and PCNA upregulation. UAE, collapsed glomeruli, PCNA staining, TGF-β, NGAL and animal survival, significantly impaired in D + BPA animals. Moreover, UAE, collapsed glomeruli and animal survival also displayed a sexual dimorphism pattern. In conclusion, oral administration of BPA is capable of promoting in the kidney alterations that resemble early DN. Further translational studies are needed to clarify the potential role of BPA in renal diseases, particularly in diabetic patients.

Magnesium lithospermate B supplementation improved prenatal Bisphenol A exposure-induced metabolic abnormalities in male offspring

Obesity is closely linked with metabolic diseases, while life and prenatal exposure to endocrine-disrupting chemicals has been implicated in the development of obesity. Magnesium lithospermate B (MLB), an active compound of Salvia miltiorrhiza (Danshen), has beneficial effects on insulin resistance and metabolic abnormalities in diet-induced obese rodents. Since exposure to endocrine-disrupting chemical Bisphenol A (BPA) during pregnancy mimics the effects of high fat diet-induced alterations of glucose and lipid metabolism in adult male offspring, the effects of daily MLB supplementation for 4 weeks on metabolic abnormalities in rats weaning from prenatal BPA-exposed dams were investigated. BPA-exposed rats developed obesity and adiposity concurrent with hyperglycemia, hyperinsulinemia, insulin resistance, hypertriglyceridemia, and elevation of circulating glucagon and free fatty acids. Increased hepatic fatty acid synthesis and decreased fatty acid β-oxidation, activation of adipocytic adipogenesis, maturation, and lipogenesis, as well as reduction of muscular glucose uptake were demonstrated in BPA-exposed rats. The aforementioned alterations were improved by MLB supplementation. Additionally, MLB displayed negative effects on glucocorticoid receptor action and inflammation, and promoted lipolysis and thermogenesis in the adipose tissues. In conclusion, our findings suggest that MLB may be a potential therapeutic compound against metabolic diseases, including maternal exposure-induced metabolic abnormalities.

Factors Associated with Exposure to Dietary Bisphenols in Adolescents

Obesogenic endocrine-disrupting chemicals, such as bisphenol A (BPA) and its analogue bisphenol S (BPS), seem to play an important role in the development of obesity, although contradictory results have been reported. The aim of the present study was to conduct a gender analysis of the factors associated with exposure to dietary bisphenols in 585 Spanish adolescents. Dietary BPA and BPS exposure was assessed using a food frequency questionnaire. Foods and macronutrients accounting for more than 95% of energy intake were selected for analysis. Stepwise regression was used to estimate the foods that most contributed to dietary bisphenol exposure in the sample. Gender-related factors associated with greater dietary bisphenol exposure were evaluated using multivariate logistic regression models. Canned tuna was the main dietary source of BPA and BPS in both adolescent boys and girls. Overweight/obese girls showed a higher risk of high dietary exposure to BPA (odds ratio (OR): 3.38, 95% confidence interval (CI): 1.25-9.07) and total bisphenols (OR: 2.81, 95% CI: 1.03-7.67) in comparison with girls with a BMI lower than 25 kg/m². Present results indicate a positive association of dietary exposure to both total bisphenols and BPA with being overweight/obese in adolescent girls.

Concentrations of bisphenol A and its associations with urinary albumin creatinine ratios across the various stages of renal function

Data from National Health and Nutrition Examination Survey for 2003-2016 for US adults aged ≥ 20 years (N = 10,942) were used to study variabilities and associations with urinary albumin creatinine ratio (UACR) in the adjusted concentrations (AGM) of urine bisphenol A (BPA) across various stages of renal function (RF). RF stages considered were RF-1 (eGFR > 90 mL/min/1.73 m²), RF-2 (60 ≤ eGFR ≤ 90 mL/min/1.73 m²), RF-3A (45 ≤ eGFR < 60 mL/min/1.73 m²), and RF-3B/4 (15 ≤ eGFR < 45 mL/min/1.73 m²). Irrespective of gender, race/ethnicity, and smoking status, AGMs for BPA were located on U-curves with point of inflection at RF-2. In general, decreases from RF-1 to RF-2 were followed by increases from RF-2 to RF-3A and from RF-3A to RF-3B/4. For example, AGMs for males were observed to be 1.52, 1.48, 1.61, and 1.69 ng/mL at RF-1, RF-2, RF-3A, and RF-3B/4 respectively. A similar U-curve was observed for those without albuminuria but for those with albuminuria, BPA levels continued increasing until RF-3A before decreasing at RF-3B/4. Severe kidney dysfunction was found to be associated with statistically significantly higher concentrations of BPA in urine. Shape of concentration curves for BPA across RF stages is determined by the balance of actively mediated secretion and reabsorption operating on both sides of renal proximal tubules during each stage of RF. Shape of concentration curves for BPA across various stages of RF was age and concentration dependent. Associations between BPA and UACR were found to be negative (p = 0.02), positive (p = 0.23), negative (p = 0.53), and negative (p < 0.01) respectively at RF-1, RF-2, RF-3A, and RF-3B/4 respectively.

Bioaccumulation and reproductive toxicity of bisphenol A in male-pregnant seahorse (Hippocampus erectus) at environmentally relevant concentrations

Seahorses, with brood pouch in adult males, are a bioindicator species that exhibit specialized reproductive strategy of "male pregnancy". Bisphenol A (BPA), one of the most pervasive endocrine-disrupting chemicals (EDCs), is hazardous for reproductive, immune, and neurological systems. However, no evidence of BPA toxicity to the male-pregnant animals is available. Herein, the reproductive toxicity of BPA was evaluated in lined seahorses (Hippocampus erectus) following exposure to environmentally relevant concentrations (10, 100, and 1000 μg/L) through physiological, histological, and transcriptional analyses. Our results indicated BPA bioaccumulation to be positively correlated with exposure doses in both sexes. Ovarian failure was only observed in the high-dose BPA treatment group, accompanied by the apoptosis of follicular cells and up-regulation of pro-apoptotic genes. However, brood pouches maintenance were surprisingly inhibited at low concentration, and transcriptomic analysis revealed disturbed profiles of genes involved in the extracellular matrix and cell-cell adhesion pathways. Interestingly, seahorse testes were less sensitive to BPA exposure than that in other teleosts. Thus, our study suggests that BPA at environmentally relevant concentrations might cause reproductive dysfunction in seahorses, potentially exerting adverse effects on the seahorse population since most of them inhabit shallow coastal areas with prevalent estrogenic contaminants.

Bisphenol A(BPA), BPS and BPB-induced oxidative stress and apoptosis mediated by mitochondria in human neuroblastoma cell lines

The analogues of biphenol A (BPA), including bisphenol S (BPS) and bisphenol B (BPB), are commonly used to replace the application of BPA in containers and wrappers of daily life. However, their safeties are questioned due to their similar chemical structure and possible physiological effects as BPA. To investigate the neurotoxic effects of BPA, BPS, and BPB as well as their underlying mechanism, IMR-32 cell line from male and SK-N-SH cell line from female were exposed respectively to BPA, BPS and BPB with concentrations of 1 nM, 10 nM, 100 nM, 1 μM, 10 μM, and 100 μM for 24 h. Additionally, 24 h exposure of BPA combining epigallocatechin gallate (EGCG) (4 μM and 8 μM for IMR-32 and SK-N-SH respectively) were conducted. Results demonstrated that BPs exposure could promote reactive oxygen species production and increase level of malondialdehyde (MDA) while decrease levels of superoxide dismutase (SOD). Intensive study revealed that after exposure to BPA mitochondrial membrane potential (MMP) dropped down and the protein expression levels of Bak-1, Bax, cytochrome c and Caspase-3 were up-regulated but Bcl-2 were down-regulated significantly. Moreover, apoptosis rate was raised and cell activity declined remarkably in the neuroblastoma cells. All the effects induced by BPA could be alleviated by the adding of EGCG, which similar alleviations could be inferred in IMR-32 and SK-N-SH cells induced by BPS and BPB. Furthermore, BPS showed lower neurotoxic effects compared to BPA and BPB. Interestingly, the neurotoxic effects of BPA on IMR-32 cells were significantly higher than those on SK-N-SH cells. In conclusion, the results suggested that BPA, BPS and BPB could induce oxidative stress and apoptosis via mitochondrial pathway in the neuroblastoma cells and male is more susceptible to BPs than female.

Public Awareness and Risk Perceptions of Endocrine Disrupting Chemicals: A Qualitative Study

Endocrine disrupting chemicals (EDCs) are exogenous chemicals found in food, consumer products, and the environment. EDCs are ubiquitous in modern life and exposure is associated with many negative health effects, such as reproductive disorders, metabolic disorders, and cancer. Scientists have deemed EDCs as a serious public health risk, yet the public's perceptions of these chemicals is poorly understood. This study aimed to qualitatively explore how aware the public is of EDCs and their attitudes, beliefs, and perceptions of EDC risk. Thirty-four participants (aged 19-65 years) took part in the six focus groups. Discussions were transcribed verbatim and Nvivo 11 was used for thematic analysis. Our results indicated that awareness of EDCs was low. Themes of EDC risk perception included perceived control, perceived severity, and similarity heuristics. Risk alleviation strategies were also discussed. Future research should use quantitative methodology and a larger sample size to validate the findings from this study. Findings from this study may aid the development of effective risk communication strategies and public health interventions.

Carcinogenic effects of bisphenol A in breast and ovarian cancers

Endocrine-disrupting chemicals (EDCs) are exogenous chemical compounds ubiquitously found in everyday life of the modern world. EDCs enter the human body where they act similarly to endogenous hormones, altering the functions of the endocrine system and causing adverse effects on human health. Bisphenol A (BPA), the principal representative of this class, is a carbon-based synthetic plastic, and a key element in manufacturing cans, reusable water bottles and medical equipment. BPA mimics the actions of estrogen on multiple levels by activating estrogen receptors α and β. BPA regulates various processes, such as cell proliferation, migration and apoptosis, leading to neoplastic changes. Considering genetic mechanisms, BPA exerts its functions via multiple oncogenic signaling pathways, including the STAT3, PI3K/AKT and MAPK pathways. Furthermore, BPA is associated with various modifications of the reproductive system in both males and females. These alterations include benign lesions, such as endometrial hyperplasia, the development of ovarian cysts, an increase in the ductal density of mammary gland cells and other preneoplastic lesions. These benign lesions may continue to develop to breast or ovarian cancer; the effects of BPA depend on various molecular and epigenetic mechanisms that dictate whether the endocrine or reproductive system is impacted, wherein preexisting benign lesions can become cancerous. The present review supports the need for continuous research on BPA, considering its widespread use and most available data suggesting a carcinogenic effect of BPA on the female reproductive system. Although most studies on BPA have been conducted in vitro with human cells or in vivo with animal models, it can be argued that more studies should be conducted in vivo with humans to further promote understanding of the impact of BPA.

Trimester-specific, gender-specific, and low-dose effects associated with non-monotonic relationships of bisphenol A on estrone, 17β-estradiol and estriol

BACKGROUND

Bisphenol A (BPA) may cause some adverse effects on human health by mimicking estrogen activities. In vitro andanimalstudies have observed the non-monotonic associations between BPA and natural estrogens, but the evidence in human study is lacking, particularly at multiple points in time during pregnancy.

OBJECTIVE

We aimed to examine the relationships between BPA and estrogens in the three trimesters among Chinese pregnant women and their gender variations.

METHODS

This study included 851 participants from a birth cohort conducted in Wuhan, China between 2014 and 2015. We measured concentrations of BPA and three estrogens (estrone (E1), 17β-estradiol (E2) and estriol (E3)) in urine samples collected in the three trimesters of pregnancy (mean for each visit: 13.0, 23.6, and 35.9 weeks' gestation). We calculated the estimated daily intakes using urinary BPA concentrations and compared them with the tolerable intake value to assess potential health risks. We used multivariate linear regression models stratified by trimester and gender to explore trimester-specific and gender-specific associations of BPA with E1, E2, and E3.

RESULTS

We found the decreased levels of estrogens (β < 0, P < 0.05) in the upper BPA quartiles over three trimesters, except for the elevated levels of E3 (β = 0.20, 95% CI: 0.02, 0.38) in the highest BPA quartile in the 2nd trimester. There were significant non-linear associations (overall associations P < 0.05, non-linear associations P < 0.05) between BPA and E3 in the three trimesters. In the gender-stratified analysis, we observed significant negative relationships (β < 0, P < 0.05) between BPA and E2 among mothers carrying male fetuses in the 1st trimester and significant associations between BPA and E3 among mothers carrying female fetuses in the 2nd trimester. However, we found no significant relationship between BPA and E2 among mothers carrying female fetuses over three trimesters.

CONCLUSIONS

Our findings support experimental evidence of non-monotonic relationships between BPA and three major estrogens, even at low doses of BPA. Mothers delivering male fetuses may be more sensitive to E2 at early pregnancy, and those delivering female fetuses may be more susceptive to E3 at mid-pregnancy.

Bisphenol A: Food Exposure and Impact on Human Health

Bisphenol A (BPA) is an industrial compound used extensively to produce synthetic polymers, such as epoxy resins, which are incorporated into the inner coating of metal cans, and also to manufacture polycarbonates with applications in bottles, including bottles of water. Several studies have reported on the transfer of this compound to food. Regarding human exposure to BPA, food intake can be considered the most serious among all the routes, not only because it potentially reaches more people in different age groups (including infants, an especially vulnerable group), but also because it inadvertently occurs over long time periods. BPA is considered an endocrine disruptor and several studies have proposed a relationship between exposure to BPA and the appearance of adverse health effects, such as cancer, infertility, diabetes, and obesity, among others. In 2015 however, the European Food Safety Authority concluded in its last scientific opinion that this compound does not pose any risk to the exposed population's health. Therefore, the EU regards BPA as an authorized product to be used as food contact material. Although BPA intake through food is apparently below the set limits, research into BPA and its potential negative effects is still ongoing. This review contains the most recent in vitro and in vivo studies on BPA toxicity and its harmful effects on health, and it intends to address human exposure to BPA, namely through dietary exposure and its impact on human health.

Elevated Metabolites of Steroidogenesis and Amino Acid Metabolism in Preadolescent Female Children With High Urinary Bisphenol A Levels: A High-Resolution Metabolomics Study

Health risks associated with bisphenol A (BPA) exposure are controversially highlighted by numerous studies. High-resolution metabolomics (HRM) can confirm these proposed associations and may provide a mechanistic insight into the connections between BPA exposure and metabolic perturbations. This study was aimed to identify the changes in metabolomics profile due to BPA exposure in urine and serum samples collected from female and male children (n = 18) aged 7-9. Urine was measured for BPA concentration, and the children were subsequently classified into high and low BPA groups. HRM, coupled with Liquid chromatography-mass spectrometry/MS, followed by multivariate statistical analysis using MetaboAnalyst 3.0, were performed on urine to discriminate metabolic profiles between high and low BPA children as well as males and females, followed by further validation of our findings in serum samples obtained from same population. Metabolic pathway analysis showed that biosynthesis of steroid hormones and 7 other pathways-amino acid and nucleotide biosynthesis, phenylalanine metabolism, tryptophan metabolism, tyrosine metabolism, lysine degradation, pyruvate metabolism, and arginine biosynthesis-were affected in high BPA children. Elevated levels of metabolites associated with these pathways in urine and serum were mainly observed in female children, while these changes were negligible in male children. Our results suggest that the steroidogenesis pathway and amino acid metabolism are the main targets of perturbation by BPA in preadolescent girls.

Persistent Endocrine-Disrupting Chemicals and Fatty Liver Disease

PURPOSE OF REVIEW

Non-alcoholic fatty liver disease (NAFLD) is the most prominent chronic liver disease in Western countries, affecting approximately 25% of the population worldwide. Sex-specific differences in the development of NAFLD are apparent. While obesity and insulin resistance are major contributors to the increasing prevalence of NAFLD, a growing body of literature suggests that exposure to persistent endocrine-disrupting chemicals (pEDCs) may also play a role. This review summarizes recent (2011 and later) scientific literature investigating exposures to pEDCs, specifically persistent organic pollutants (POPs), and NAFLD, with a focus on sex-specific associations.

RECENT FINDINGS

The overwhelming majority of studies were conducted in single-sex animal models and provide biological evidence that exposures to 2,3,7,8-tetrachlorodibenzo-p-dioxin polychlorinated biphenyls, and other POPs or POP mixtures are negatively associated with liver health. There were four cross-sectional epidemiological studies in humans that reported associations for several POPs, including polychlorinated biphenyls and perfluorinated chemicals, with elevated liver enzymes. Only one of these studies, using a sample of gastric bypass surgery patients, examined sex-specific associations of POPs and liver enzymes, finding adverse associations among women only. The noticeable lack of studies investigating how differences (i.e., biochemical, physiological, and behavioral) between men and women may influence associations of pEDCs and NAFLD represents a large research gap in environmental health. Sexual dimorphism in metabolic processes throughout the body, including the liver, is established but often overlooked in the designs and analyses of studies. Other factors identified in this review that may also act to modulate associations of environmental chemicals and NAFLD are reproductive status and dietary nutrient intakes, which also remain understudied in the literature. Despite knowledge of sexual dimorphism in the actions of pEDCs, as well as in metabolic processes related to NAFLD development, few experimental or epidemiological studies have investigated sex-dependent associations. Future studies, especially those in humans, should be designed to address this research need. Consideration of other factors, such as reproductive status, dietary intakes, and mixtures of chemicals with varying endocrine-disrupting capabilities, should be explored.

Effects of Low-Dose Developmental Bisphenol A Exposure on Metabolic Parameters and Gene Expression in Male and Female Fischer 344 Rat Offspring

BACKGROUND

Bisphenol A (BPA) is an endocrine-disrupting chemical that may contribute to development of obesity and metabolic disorders. Humans are constantly exposed to low concentrations of BPA, and studies support that the developmental period is particularly sensitive.

OBJECTIVES

The aim was to investigate the effects of low-dose developmental BPA exposure on metabolic parameters in male and female Fischer 344 (F344) rat offspring.

METHODS

Pregnant F344 rats were exposed to BPA via their drinking water, corresponding to 0.5 μg/kg BW/d (BPA0.5; n=21) or 50 μg/kg BW/d (BPA50; n=16), from gestational day (GD) 3.5 until postnatal day (PND) 22, and controls were given vehicle (n=26). Body weight (BW), adipose tissue, liver (weight, histology, and gene expression), heart weight, and lipid profile were investigated in the 5-wk-old offspring.

RESULTS

Males and females exhibited differential susceptibility to the different doses of BPA. Developmental BPA exposure increased plasma triglyceride levels (0.81±0.10 mmol/L compared with 0.57±0.03 mmol/L, females BPA50 p=0.04; 0.81±0.05 mmol/L compared with 0.61±0.04 mmol/L, males BPA0.5 p=0.005) in F344 rat offspring compared with controls. BPA exposure also increased adipocyte cell density by 122% in inguinal white adipose tissue (iWAT) of female offspring exposed to BPA0.5 compared with controls (68.2±4.4 number of adipocytes/HPF compared with 55.9±1.5 number of adipocytes/HPF; p=0.03) and by 123% in BPA0.5 females compared with BPA50 animals (68.2±4.4 number of adipocytes/high power field (HPF) compared with 55.3±2.9 number of adipocytes/HPF; p=0.04). In iWAT of male offspring, adipocyte cell density was increased by 129% in BPA50-exposed animals compared with BPA0.5-exposed animals (69.9±5.1 number of adipocytes/HPF compared with 54.0±3.4 number of adipocytes/HPF; p=0.03). Furthermore, the expression of genes involved in lipid and adipocyte homeostasis was significantly different between exposed animals and controls depending on the tissue, dose, and sex.

CONCLUSIONS

Developmental exposure to 0.5 μg/kg BW/d of BPA, which is 8-10 times lower than the current preliminary EFSA (European Food Safety Authority) tolerable daily intake (TDI) of 4 μg/kg BW/d and is within the range of environmentally relevant levels, was associated with sex-specific differences in the expression of genes in adipose tissue plasma triglyceride levels in males and adipocyte cell density in females when F344 rat offspring of dams exposed to BPA at 0.5 μg/kg BW/d were compared with the offspring of unexposed controls. https://doi.org/10.1289/EHP505.

Influence of Bisphenol A on Type 2 Diabetes Mellitus

Bisphenol A (BPA) is an organic synthetic compound employed to produce plastics and epoxy resins. It is used as a structural component in polycarbonate beverage bottles and as coating for metal surface in food containers and packaging. The adverse effects of BPA on human health are widely disputed. BPA has been recently associated with a wide variety of medical disorders and, in particular, it was identified as potential endocrine-disrupting compound with diabetogenic action. Most of the clinical observational studies in humans reveal a positive link between BPA exposure, evaluated by the measurement of urinary BPA levels, and the risk of developing type 2 diabetes mellitus. Clinical studies on humans and preclinical studies on in vivo, ex vivo, and in vitro models indicate that BPA, mostly at low doses, may have a role in increasing type 2 diabetes mellitus developmental risk, directly acting on pancreatic cells, in which BPA induces the impairment of insulin and glucagon secretion, triggers inhibition of cell growth and apoptosis, and acts on muscle, hepatic, and adipose cell function, triggering an insulin-resistant state. The current review summarizes the available evidences regarding the association between BPA and type 2 diabetes mellitus, focusing on both clinical and preclinical studies.