Long-term exposure to bisphenol A or S promotes glucose intolerance and changes hepatic mitochondrial metabolism in male Wistar rats

Deciphering the molecular mechanism of NLRP3 in BPA-mediated toxicity: Implications for targeted therapies

Bisphenol-A (BPA), a pervasive industrial chemical used in polymer synthesis, is found in numerous consumer products including food packaging, medical devices, and resins. Detectable in a majority of the global population, BPA exposure occurs via ingestion, inhalation, and dermal routes. Extensive research has demonstrated the adverse health effects of BPA, particularly its disruption of immune and endocrine systems, along with genotoxic potential. This review focuses on the complex relationship between BPA exposure and the NOD-like receptor protein 3 (NLRP3) inflammasome, a multiprotein complex central to inflammatory disease processes. We examine how BPA induces oxidative stress through the generation of intracellular free radicals, subsequently activating NLRP3 signaling. The mechanistic details of this process are explored, including the involvement of signaling cascades such as PI3K/AKT, JAK/STAT, AMPK/mTOR, and ERK/MAPK, which are implicated in NLRP3 inflammasome activation. A key focus of this review is the wide-ranging organ toxicities associated with BPA exposure, including hepatic, renal, gastrointestinal, and cardiovascular dysfunction. We investigate the immunopathogenesis and molecular pathways driving these injuries, highlighting the interplay among BPA, oxidative stress, and the NLRP3 inflammasome. Finally, this review explores the emerging concept of targeting NLRP3 as a potential therapeutic strategy to mitigate the organ toxicities stemming from BPA exposure. This work integrates current knowledge, emphasizes complex molecular mechanisms, and promotes further research into NLRP3-targeted interventions.

Cardiac energy metabolism disorder mediated by energy substrate imbalance and mitochondrial damage upon tebuconazole exposure

Tebuconazole exposure has been described as an increasing hazard to human health. An increasing number of recent studies have shown a positive association between tebuconazole exposure and cardiovascular disease risk, which is characterized by the reduction of adenosine triphosphate (ATP) synthesis. However, researches on the damage of tebuconazole exposure to energy metabolism and the related molecular mechanisms are limited. In the present study, male C57BL/6 mice were treated with tebuconazole at different low concentrations for 4 weeks. The results indicated that tebuconazole could accumulate in the heart and further induce the decrease of ATP content in the mouse heart. Importantly, tebuconazole induced an obvious shift in substrate utilization of fatty acid and glucose by disrupting their corresponding transporters (GLUT1, GLUT4, CD36, FABP3 and FATP1) expression, and significantly repressed the expression of mitochondrial biogenesis (Gabpa and Tfam) and oxidative phosphorylation (CS, Ndufa4, Sdhb, Cox5a and Atp5b) related genes in a dose-dependent manner. Further investigation revealed that these alterations were related to the IRS1/AKT and PPARγ/RXRα pathways. These findings contribute to a better understanding of triazole fungicide-induced cardiovascular disease by revealing the key indicators associated with this phenomenon.

Bisphenol S, bisphenol F, bisphenol a exposure and body composition in US adults

Bisphenol S (BPS) and bisphenol F (BPF) are increasingly used to replace bisphenol A (BPA), an endocrine-disrupting chemical with putative obesogenic properties; whether and how BPS and BPF affect adiposity in humans remains to be determined. Therefore, we examined the association of BPA, BPS， and BPF with body composition among US adults. We included 1787 participants aged 20-59 years old in the National Health and Nutrition Examination Survey 2013-2016 who had information on urinary BPA, BPS, and BPF concentrations, and body composition measured using dual-energy x-ray absorptiometry. After full adjustment for potential confounders in linear regression models, BPA was significantly associated with the % body fat of the whole body, arm, and leg, with the β (95% CI) for the highest quartile vs. the lowest quartile of 1.34 (95%CI [0.11, 2.58], P = 0.03), 1.60 (95%CI [0.20, 3.00], P = 0.03), and 1.63 (95%CI [0.24, 3.02], P = 0.02), respectively. No association between BPA and lean mass was found. For BPS, significant associations were found for % body fat of the whole body (β [95% CI] = 1.42 [0.49, 2.36], P = 0.004), trunk (β[95% CI] = 1.92 [0.86, 2.97], P = 0.001), and arm (β [95% CI] = 1.60 [0.49, 2.70], P = 0.01), as well as lean mass of the whole body (β [95% CI] = 2610.6 [1324.3, 3896.8], P < 0.001), trunk (β [95% CI] = 1467.0 [745.3, 2188.7], P < 0.001), arm (β [95% CI] = 113.4 [10.3, 216.5], P = 0.03), and leg (β [95% CI] = 431.5 [219.6, 643.4], P < 0.001), comparing the third quartile vs. the lowest quartile. No significant association was observed between BPF and % body fat and lean mass. Results suggest that higher BPA levels were significantly associated with greater % body fat of the whole body and limbs, and there was suggestive evidence that BPS levels were associated with both % body fat and lean mass of the whole body and body parts in a nonmonotonic relationship.

Multilevel meta-analysis and dose-response analysis for bisphenol A (BPA) exposure on metabolic and neurobehavioral effects

Evidence suggests that oral exposure to bisphenol A (BPA) may result in adverse metabolic and neurobehavioral effects. The aim of the present meta-analysis is to examine this association based on systematically selected laboratory rodent studies published from 2012 to 2021 and sourced from Scopus, Web of Science, EmBase, and PubMed. Articles satisfying eligibility and inclusion criteria were included for the calculation of the summary standardised mean difference (SMD). Subgroup analysis and subsequent dose-response analysis were conducted if applicable. In total, 32 studies were analysed for 6 metabolic endpoints (cholesterol, triglycerides, insulin, glucose, leptin, and adiponectin) and 6 neurobehavioral endpoints (locomotor activity, exploratory, anxiety, depression, spatial learning and memory, non-spatial learning and memory). Summary SMDs implied that no significant effects were observed in endpoints considered. The dose was not determined as a significant moderator with regards to medium or high heterogeneity; however, there was significant impairment of spatial learning and memory at health-based guidance value ('HBGV') (0.05-9 mg (kg bw)-1 day-1) and 'High' (>9 mg (kg bw)-1 day-1) dose group. As a result, an indicative toxicological reference dose value of 0.034 mg (kg bw)-1 day-1 was proposed due to large variability. Potential harm to spatial learning and memory from BPA exposure requires further investigation. This study has provided some additional information on potential adverse metabolic and neurobehavioral effects of BPA from the perspective of meta-analysis which can inform the public, regulatory authorities, and policymakers.

A New In Vivo Zebrafish Bioassay Evaluating Liver Steatosis Identifies DDE as a Steatogenic Endocrine Disruptor, Partly through SCD1 Regulation

Non-alcoholic fatty liver disease (NAFLD), which starts with liver steatosis, is a growing worldwide epidemic responsible for chronic liver diseases. Among its risk factors, exposure to environmental contaminants, such as endocrine disrupting compounds (EDC), has been recently emphasized. Given this important public health concern, regulation agencies need novel simple and fast biological tests to evaluate chemical risks. In this context, we developed a new in vivo bioassay called StAZ (Steatogenic Assay on Zebrafish) using an alternative model to animal experimentation, the zebrafish larva, to screen EDCs for their steatogenic properties. Taking advantage of the transparency of zebrafish larvae, we established a method based on fluorescent staining with Nile red to estimate liver lipid content. Following testing of known steatogenic molecules, 10 EDCs suspected to induce metabolic disorders were screened and DDE, the main metabolite of the insecticide DDT, was identified as a potent inducer of steatosis. To confirm this and optimize the assay, we used it in a transgenic zebrafish line expressing a blue fluorescent liver protein reporter. To obtain insight into DDE's effect, the expression of several genes related to steatosis was analyzed; an up-regulation of scd1 expression, probably relying on PXR activation, was found, partly responsible for both membrane remodeling and steatosis.

Preconceptional exposure of adult male rats to bisphenol S impairs insulin sensitivity and glucose tolerance in their male offspring

Since the use of bisphenol A (BPA) has been restricted because of its endocrine disruptor properties, bisphenol S (BPS) has been widely used as a substitute of BPA. However, BPS exerts similar effects on metabolic health as BPA. The effects of maternal exposure to BPA and BPS on the metabolic health of offspring have been largely documented during the past decade. However, the impact of preconceptional paternal exposure to BPS on progenies remains unexplored. In this study we investigated the impact of paternal exposure to BPS before conception, on the metabolic phenotype of offspring. Male Wistar rats were administered BPS through drinking water at the dose of 4 μg/kg/day (BPS-4 sires) or 40 μg/kg/day (BPS-40 sires) for 2 months before mating with females. The progenies (F1) were studied at fetal stage and in adulthood. We showed that preconceptional paternal exposure to BPS for 2 months did not alter the metabolic status of sires. The female offspring of sires exposed to lower or higher doses of BPS showed no alteration of their metabolic phenotype compared to females from control sires. In contrast, male offspring of BPS-4 sires exhibited increased body weight and body fat/lean ratio, decreased insulin sensitivity and increased glucose-induced insulin secretion at adult age, compared to the male offspring of control sires. Moreover, male offspring of BPS-4 sires developed glucose intolerance later in life. None of these effects were apparent in male offspring of BPS-40 sires. In conclusion, our study provides the first evidence of the non-monotonic and sex-specific effects of preconceptional paternal exposure to BPS on the metabolic health of offspring, suggesting that BPS is not a safe BPA substitute regarding the inter-generational transmission of metabolic disorders through the paternal lineage.

Beneficial antioxidant effects of Coenzyme Q10 on reproduction

This chapter focuses on preclinical and clinical studies conducted in recent years that contribute to increasing knowledge on the role of Coenzyme Q10 in female reproductive health. General aspects of CoQ10, such as its role as an antioxidant and in mitochondrial bioenergetics are considered. The age-dependent decline in human female reproductive potential is associated with cellular mitochondrial dysfunction and oxidative stress, and in some cases accompanied by a decrease in CoQ10 levels. Herein, we discuss experimental and clinical evidence on CoQ10 protective effects on reproductive health. We also address the potential of supplementation with this coenzyme to rescue reprotoxicity induced by exposure to environmental xenobiotics. This review not only contributes to our general understanding of the effects of aging on female reproduction but also provides new insights into strategies promoting reproductive health. The use of CoQ10 supplementation can improve reproductive performance through the scavenging of reactive oxygen species and free radicals. This strategy can constitute a low-risk and low-cost strategy to attenuate the impact on fertility related to aging and exposure to environmental chemicals.

Exposure to Bisphenol A Substitutes, Bisphenol S and Bisphenol F, and Its Association with Developing Obesity and Diabetes Mellitus: A Narrative Review

Bisphenol A, a well-known endocrine-disrupting chemical, has been replaced with its analogs bisphenol S (BPS) and bisphenol F (BPF) over the last decade due to health concerns. BPS and BPF are present in relatively high concentrations in different products, such as food products, personal care products, and sales receipts. Both BPS and BPF have similar structural and chemical properties to BPA; therefore, considerable scientific efforts have investigated the safety of their exposure. In this review, we summarize the findings of relevant epidemiological studies investigating the association between urinary concentrations of BPS and/or BPF with the incidence of obesity or diabetes. The results showed that BPS and BPF were detected in many urinary samples at median concentrations ranging from 0.03 to 0.4 µg·L-1. At this exposure level, BPS median urinary concentrations (0.4 µg·L-1) were associated with the development of obesity. At a lower exposure level (0.1-0.03 µg·L-1), two studies showed an association with developing diabetes. For BPF exposure, only one study showed an association with obesity. However, most of the reported studies only assessed BPS exposure levels. Furthermore, we also summarize the findings of experimental studies in vivo and in vitro regarding our aim; results support the possible obesogenic effects/metabolic disorders mediated by BPS and/or BPF exposure. Unexpectedly, BPS may promote worse obesogenic effects than BPA. In addition, the possible mode of action underlying the obesogenic effects of BPS might be attributed to various pathophysiological mechanisms, including estrogenic or androgenic activities, alterations in the gene expression of critical adipogenesis-related markers, and induction of oxidative stress and an inflammatory state. Furthermore, susceptibility to the adverse effects of BPS may be altered by sex differences according to the results of both epidemiological and experimental studies. However, the possible mode of action underlying these sex differences is still unclear. In conclusion, exposure to BPS or BPF may promote the development of obesity and diabetes. Future approaches are highly needed to assess the safety of BPS and BPF regarding their potential effects in promoting metabolic disturbances. Other studies in different populations and settings are highly suggested.

Cytotoxicity, redox and immune status in African catfish, Clarias gariepinus (Burchell, 1822) exposed to bisphenol A (BPA) and its analogues

The objective of the study was to determine the comparative toxicities and immune dysfunction in the African catfish, Clarias gariepinus, exposed to bisphenol A (BPA) and its two analogues: bisphenol AP (BPAP) and bisphenol P (BPP). Juveniles of C. gariepinus were exposed to sublethal concentrations (70 and 140 μg/L) of BPA, BPAP and BPP for 7, 14 or 21 days after which various endpoints which are indicative of cytotoxicity, oxidative stress and haematological and innate immune parameters were determined in the liver homogenates or blood plasma. The exposure of C. gariepinus to BPA and its analogues caused significant increased activities of lactate dehydrogenase, catalase and superoxide dismutase. The exposed fish had increased levels of DNA fragmentation, lipid peroxidation, white blood cells, nitric oxide and respiratory burst, while the red blood cell counts and the percentage packed cell volume decreased significantly in the exposed fish compared to control. The toxic effects elicited by the bisphenols were both concentration- and duration-dependent. Generally, BPA exerted the most toxic effects on the fish, followed by BPAP, while BPP exerted the least toxic effects to C. gariepinus. Summarily, the findings indicated that BPA and its two analogues studied in the research are capable of causing cytotoxicity, oxidative stress and immune dysfunction in C. gariepinus.

Maternal perinatal exposure to bisphenol S induces an estrogenic like effect in glucose homeostasis in male offspring

Bisphenol S (BPS) has been introduced into the industry as a safer alternative to bisphenol A (BPA). However, the recent studies have reported a possible association between BPS and disturbed glucose homeostasis, indicating that it may be a risk factor for type 1 and type 2 diabetes mellitus, obesity, and gestational diabetes mellitus. Nevertheless, the role of BPS in glucose metabolism remains controversial. In this study, we investigated the glucose metabolism of male Wistar rats born from dams that were BPS-exposed (groups: BPS-L (0.05 mg/kg/day), BPS-H (20 mg/kg/day)) during pregnancy and lactation. We observed that both BPS treated groups of animals presented a significant decrease in anogenital distance/weight^1/3 , as compared to control animals, although no alterations in testosterone levels were observed. Furthermore, the BPS-L group presented a significant decrease in body weight from postnatal day (PND) 21 to adult stage. In addition, a significant increase in glucose tolerance, pancreatic β-cell proliferation, the frequency of small islets, and the average β-cell size at PND 36 was observed in this group. However, no changes in insulin serum levels and percentage of β-cells were recorded. Furthermore, these changes were not preserved at the adult stage (PND 120). The results suggest that the administration of low doses of BPS during the perinatal period induced an estrogenic like effect, with males apparently becoming more female-like in their responses to a glucose challenge.

Increased gut serotonin production in response to bisphenol A structural analogs may contribute to their obesogenic effects

Obesogens are synthetic, environmental chemicals that can disrupt endocrine control of metabolism and contribute to the risk of obesity and metabolic disease. Bisphenol A (BPA) is one of the most studied obesogens. There is considerable evidence that BPA exposure is associated with weight gain, increased adiposity, poor blood glucose control, and nonalcoholic fatty liver disease in animal models and human populations. Increased usage of structural analogs of BPA has occurred in response to legislation banning their use in some commercial products. However, BPA analogs may also cause some of the same metabolic impairments because of common mechanisms of action. One key effector that is altered by BPA and its analogs is serotonin, however, it is unknown if BPA-induced changes in peripheral serotonin pathways underlie metabolic perturbations seen with BPA exposure. Upon ingestion, BPA and its analogs act as endocrine-disrupting chemicals in the gastrointestinal tract to influence serotonin production by the gut, where over 95% of serotonin is produced. The purpose of this review is to evaluate how BPA and its analogs alter gut serotonin regulation and then discuss how disruption of serotonergic networks influences host metabolism. We also provide evidence that BPA and its analogs enhance serotonin production in gut enterochromaffin cells. Taken together, we propose that BPA and many BPA analogs represent endocrine-disrupting chemicals that can influence host metabolism through the endogenous production of gut-derived factors, such as serotonin.

The alternative analog plasticizer BPS displays similar phenotypic and metabolomic responses to BPA in HepG2 and INS-1E cells

Bisphenols A (BPA) and S (BPS) are endocrine-disrupting chemicals that affect energy metabolism, leading to impairment of glucose and lipid homeostasis. We aimed at identifying metabolic pathways regulated by both compounds in human liver cells and rat pancreatic β-cells that could impair energy homeostasis regulation. We assessed the effects on growth, proliferation, and viability of hepatocarcinoma (HepG2) and insulinoma (INS-1E) cells exposed to either BPA or BPS in a full range concentration between 0.001 and 100 μM. Both the dose and duration of exposure caused a differential response on growth and viability of both cells. Effects were more pronounced on HepG2, as these cells exhibited non-linear dose-responses following exposure to xenobiotics. For INS-1E, effect was observed only at the highest concentration. In addition, we profiled their intracellular state by untargeted metabolomics at 24, 48, and 72 h of exposure. This analysis revealed time- and dose-dependently molecular changes for HepG2 and INS-1E that were similar between BPA and BPS. Both increased levels of inflammatory mediators, such as metabolites pertaining to linolenic and linoleic acid metabolic pathway. In summary, this study shows that BPS also disrupts molecular functions in cells that regulate energy homeostasis, displaying similar but less pronounced responses than BPA.

Regulatory and academic studies to derive reference values for human health: The case of bisphenol S

The close structural analogy of bisphenol (BP) S with BPA, a recognized endocrine-disrupting chemical and a substance of very high concern in the European Union, highlights the need to assess the extent of similarities between the two compounds and carefully scrutinize BPS potential toxicity for human health. This analysis aimed to investigate human health toxicity data regarding BPS, to find a point of departure for the derivation of human guidance values. A systematic and transparent methodology was applied to determine whether European or international reference values have been established for BPS. In the absence of such values, the scientific literature on human health effects was evaluated by focusing on human epidemiological and animal experimental studies. The results were analyzed by target organ/system: male and female reproduction, mammary gland, neurobehavior, and metabolism/obesity. Academic experimental studies were analyzed and compared to regulatory data including subchronic studies and an extended one-generation and reproduction study. In contrast to the regulatory studies, which were performed at dose levels in the mg/kg bw/day range, the academic dataset on specific target organs or systems showed adverse effects for BPS at much lower doses (0.5-10 μg/kg bw/day). A large disparity between the lowest-observed-adverse-effect levels (LOAELs) derived from regulatory and academic studies was observed for BPS, as for BPA. Toxicokinetic data on BPS from animal and human studies were also analyzed and showed a 100-fold higher oral bioavailability compared to BPA in a pig model. The similarities and differences between the two bisphenols, in particular the higher bioavailability of BPS in its active (non-conjugated) form and its potential impact on human health, are discussed. Based on the available experimental data, and for a better human protection, we propose to derive human reference values for exposure to BPS from the N(L)OAELs determined in academic studies.

Oral Bisphenol A Worsens Liver Immune-Metabolic and Mitochondrial Dysfunction Induced by High-Fat Diet in Adult Mice: Cross-Talk between Oxidative Stress and Inflammasome Pathway

Lines of evidence have shown the embryogenic and transgenerational impact of bisphenol A (BPA), an endocrine-disrupting chemical, on immune-metabolic alterations, inflammation, and oxidative stress, while BPA toxic effects in adult obese mice are still overlooked. Here, we evaluate BPA’s worsening effect on several hepatic maladaptive processes associated to high-fat diet (HFD)-induced obesity in mice. After 12 weeks HFD feeding, C57Bl/6J male mice were exposed daily to BPA (50 μg/kg per os) along with HFD for 3 weeks. Glucose tolerance and lipid metabolism were examined in serum and/or liver. Hepatic oxidative damage (reactive oxygen species, malondialdehyde, antioxidant enzymes), and mitochondrial respiratory capacity were evaluated. Moreover, liver damage progression and inflammatory/immune response were determined by histological and molecular analysis. BPA amplified HFD-induced alteration of key factors involved in glucose and lipid metabolism, liver triglycerides accumulation, and worsened mitochondrial dysfunction by increasing oxidative stress and reducing antioxidant defense. The exacerbation by BPA of hepatic immune-metabolic dysfunction induced by HFD was shown by increased toll-like receptor-4 and its downstream pathways (i.e., NF-kB and NLRP3 inflammasome) amplifying inflammatory cytokine transcription and promoting fibrosis progression. This study evidences that BPA exposure represents an additional risk factor for the progression of fatty liver diseases strictly related to the cross-talk between oxidative stress and immune-metabolic impairment due to obesity.

Mechanism investigation on Bisphenol S-induced oxidative stress and inflammation in murine RAW264.7 cells: The role of NLRP3 inflammasome, TLR4, Nrf2 and MAPK

Bisphenol S is considered as a safer alternative to bisphenol A. In the present study, we used murine macrophages to investigate the effects of BPS exposure on oxidative stress and inflammatory response as well as the underlying mechanism. Cells were exposed to BPS at various concentrations for short period of times. Results showed that 10^-8 M BPS triggered oxidative stress by increasing ROS/RNS production, increased the levels of oxidant enzyme NOX1/2, and decreased the levels of antioxidant enzymes SOD1/2, CAT and GSH-Px. 10^-8 M BPS exposure significantly induced the production of proinflammatory mediators. Activation of the NLRP3 inflammasome, TLR4, and MAPK pathways was involved in this process. Furthermore, we illustrated that NAC pretreatment diminished these effects triggered by BPS exposure. Collectively, our data suggested that BPS at a dose relevant to human serum concentration induced oxidative stress and inflammatory response in macrophages. These novel findings shed light on the concerns regarding the potential adverse effects of BPS exposure that requires further careful attention.

Global liver proteomic analysis of Wistar rats chronically exposed to low-levels of bisphenol A and S

Exposure to bisphenol A (BPA) and bisphenol S (BPS) has been associated with the development of metabolic disorders, such as obesity, dyslipidemias, and nonalcoholic fatty liver disease. Nonetheless, the associated mechanisms are still not fully understood. BPS is being used with no restrictions to replace BPA, which increases the concern regarding its safety and claims for further investigation on its potential mechanisms of toxicity. The present study aims to access liver molecular disturbances which could be associated with systemic metabolic disorders following exposure to BPA or BPS. Therefore, body weight gain and serum biochemical parameters were measured in male Wistar rats chronically exposed to 50 or 500 µg/kg/day of BPA or BPS, while an extensive evaluation of liver protein expression changes was conducted after exposure to 50 µg/kg/day of both compounds. Exposure to the lowest dose of BPA led to the development of hyperglycemia and hypercholesterolemia, while the BPS lowest dose led to the development of hypertriglyceridemia. Besides, exposure to 500 µg/kg/day of BPS significantly increased body weight gain and LDL-cholesterol levels. Hepatic proteins differentially expressed in BPA and BPS-exposed groups compared to the control group were mostly related to lipid metabolism and synthesis, with upregulation of glucokinase activity-related sequence 1 (1.8-fold in BPA and 2.4-fold in BPS), which is involved in glycerol triglycerides synthesis, and hydroxymethylglutaryl-CoA synthase cytoplasmic (2-fold in BPS), an enzyme involved in mevalonate biosynthesis. Essential mitochondrial proteins of the electron transport chain were upregulated after exposure to both contaminants. Also, BPA and BPS dysregulated expression of liver antioxidant enzymes, which are involved in cellular reactive oxygen species detoxification. Altogether, the results of the present study contribute to expand the scientific understanding of how BPA and BPS lead to the development of metabolic disorders and reinforce the risks associated with exposure to these contaminants.

Hydrothermal synthesis of NiFe2O4 nanoparticles as an efficient electrocatalyst for the electrochemical detection of bisphenol A

In this study, the sensitive and selective detection of bisphenol A (BPA) was achieved using a screen-printed carbon electrode (NFO/SPCE) modified with hydrothermally synthesized NiFe₂O₄ nanoparticles.