Role of bisphenol A as environmental factor in the promotion of non-alcoholic fatty liver disease: in vitro and clinical study

The Impact of the Aryl Hydrocarbon Receptor on Antenatal Chemical Exposure-Induced Cardiovascular-Kidney-Metabolic Programming

Early life exposure lays the groundwork for the risk of developing cardiovascular-kidney-metabolic (CKM) syndrome in adulthood. Various environmental chemicals to which pregnant mothers are commonly exposed can disrupt fetal programming, leading to a wide range of CKM phenotypes. The aryl hydrocarbon receptor (AHR) has a key role as a ligand-activated transcription factor in sensing these environmental chemicals. Activating AHR through exposure to environmental chemicals has been documented for its adverse impacts on cardiovascular diseases, hypertension, diabetes, obesity, kidney disease, and non-alcoholic fatty liver disease, as evidenced by both epidemiological and animal studies. In this review, we compile current human evidence and findings from animal models that support the connection between antenatal chemical exposures and CKM programming, focusing particularly on AHR signaling. Additionally, we explore potential AHR modulators aimed at preventing CKM syndrome. As the pioneering review to present evidence advocating for the avoidance of toxic chemical exposure during pregnancy and deepening our understanding of AHR signaling, this has the potential to mitigate the global burden of CKM syndrome in the future.

Global epidemiology of type 2 diabetes in patients with NAFLD or MAFLD: a systematic review and meta-analysis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) and metabolic-associated fatty liver disease (MAFLD) shares common pathophysiological mechanisms with type 2 diabetes, making them significant risk factors for type 2 diabetes. The present study aimed to assess the epidemiological feature of type 2 diabetes in patients with NAFLD or MAFLD at global levels.

METHODS

Published studies were searched for terms that included type 2 diabetes, and NAFLD or MAFLD using PubMed, EMBASE, MEDLINE, and Web of Science databases from their inception to December 2022. The pooled global and regional prevalence and incidence density of type 2 diabetes in patients with NAFLD or MAFLD were evaluated using random-effects meta-analysis. Potential sources of heterogeneity were investigated using stratified meta-analysis and meta-regression.

RESULTS

A total of 395 studies (6,878,568 participants with NAFLD; 1,172,637 participants with MAFLD) from 40 countries or areas were included in the meta-analysis. The pooled prevalence of type 2 diabetes among NAFLD or MAFLD patients was 28.3% (95% confidence interval 25.2-31.6%) and 26.2% (23.9-28.6%) globally. The incidence density of type 2 diabetes in NAFLD or MAFLD patients was 24.6 per 1000-person year (20.7 to 29.2) and 26.9 per 1000-person year (7.3 to 44.4), respectively.

CONCLUSIONS

The present study describes the global prevalence and incidence of type 2 diabetes in patients with NAFLD or MAFLD. The study findings serve as a valuable resource to assess the global clinical and economic impact of type 2 diabetes in patients with NAFLD or MAFLD.

Effects of Behavioral, Clinical, and Policy Interventions in Reducing Human Exposure to Bisphenols and Phthalates: A Scoping Review

BACKGROUND

There is growing interest in evidence-based interventions, programs, and policies to mitigate exposures to bisphenols and phthalates and in using implementation science frameworks to evaluate hypotheses regarding the importance of specific approaches to individual or household behavior change or institutions adopting interventions.

OBJECTIVES

This scoping review aimed to identify, categorize, and summarize the effects of behavioral, clinical, and policy interventions focused on exposure to the most widely used and studied bisphenols [bisphenol A (BPA), bisphenol S (BPS), and bisphenol F (BPF)] and phthalates with an implementation science lens.

METHODS

A comprehensive search of all individual behavior, clinical, and policy interventions to reduce exposure to bisphenols and phthalates was conducted using PubMed, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Google Scholar. We included studies published between January 2000 and November 2022. Two reviewers screened references in CADIMA, then extracted data (population characteristics, intervention design, chemicals assessed, and outcomes) for studies meeting inclusion criteria for the present review.

RESULTS

A total of 58 interventions met the inclusion criteria. We classified interventions as dietary (n = 27 ), clinical (n = 13 ), policy (n = 14 ), and those falling outside of these three categories as "other" (n = 4 ). Most interventions (81%, 47/58) demonstrated a decrease in exposure to bisphenols and/or phthalates, with policy level interventions having the largest magnitude of effect.

DISCUSSION

Studies evaluating policy interventions that targeted the reduction of phthalates and BPA in goods and packaging showed widespread, long-term impact on decreasing exposure to bisphenols and phthalates. Clinical interventions removing bisphenol and phthalate materials from medical devices and equipment showed overall reductions in exposure biomarkers. Dietary interventions tended to lower exposure with the greatest magnitude of effect in trials where fresh foods were provided to participants. The lower exposure reductions observed in pragmatic nutrition education trials and the lack of diversity (sociodemographic backgrounds) present limitations for generalizability to all populations. https://doi.org/10.1289/EHP11760.

Endocrine disrupting chemical Bisphenol A and its association with cancer mortality: a prospective cohort study of NHANES

Introduction

There is evidence suggesting that Bisphenol A (BPA) is associated with increased all-cause mortality in adults. However, the specific nature of the relationship between BPA exposure and cancer mortality remains relatively unexplored.

Methods

The National Health and Nutrition Examination Survey (NHANES) dataset was used to recruit participants. Urinary BPA was assessed using liquid chromatography-mass spectrum (LC-MS). Through the use of multivariable Cox proportional hazard regressions and constrained cubic splines, the relationships between urine BPA and death from all causes and cancer were investigated.

Results

This study has a total of 8,035 participants, and 137 died from cancers after a 7.5-year follow-up. The median level of BPA was 2.0 g/mL. Urinary BPA levels were not independently associated with all-cause mortality. For cancer mortality, the second quartile's multivariable-adjusted hazard ratio was 0.51 (95% confidence interval: 0.30 to 0.86; p = 0.011) compared to the lowest quartile. The restricted cubic splines showed that the association was nonlinear (p for nonlinearity = 0.028) and the inflection point was 1.99 ng/mL.

Conclusion

Urinary BPA exposure was U-shaped associated with the risk of cancer mortality, and a lower level of BPA less than 1.99 ng/mL was associated with a higher risk of cancer mortality.

Ultra-processed food consumption and non-alcoholic fatty liver disease, metabolic syndrome and insulin resistance: A systematic review

Background

High ultra-processed food (UPF) consumption is associated with the development of various diet-related non-communicable diseases, especially obesity and type 2 diabetes. The present study aimed to systematically review the association between UPF consumption and non-alcoholic fatty liver disease (NAFLD) and its leading risk factors; metabolic syndrome (MetS) and insulin resistance (IR).

Methods

A comprehensive search was conducted in PubMed, Scopus, Embase, Web of Science, CINAHL, and Cochrane (March 2023), and references of the identified articles were checked. The search keywords were defined through an exploratory investigation in addition to MeSH and similarly controlled vocabulary thesauruses. Observational and interventional studies were included. Studies that focused only on specific groups of processed foods or overlapping dietary patterns were excluded. The quality assessment was conducted using the Joanna Briggs Institute's critical appraisal tools for observational studies and Cochrane's risk of bias 2 tool for randomized-control trials. A narrative synthesis was employed to report the results.

Results

Fifteen studies were included, with a total of 52,885 participants, one randomized-controlled trial, and fourteen observational studies (nine cross-sectional and five prospective). The review has shown a significant association between UPF consumption and NAFLD in three studies out of six, MetS in five out of eight, and IR in one out of three. All large-scale prospective cohorts that studied NAFLD or MetS outcomes demonstrated a positive association. In contrast, studies that did not demonstrate significant associations were mostly cross-sectional and small. The evidence for an association with IR was insufficient and conflicting.

Conclusion

The included studies are few, observational, and based upon self-reported dietary assessment tools. However, current evidence indicates that UPF is not only associated with obesity and type 2 diabetes but may also be a risk factor for NAFLD and MetS. UPF is a worldwide concern deserving further longitudinal research.

Impact and implications

Overconsumption of ultra-processed food (UPF) may lead to the development of obesity and type 2 diabetes, but the association with non-alcoholic fatty liver disease (NAFLD) is not well established. The present systematic review shows that UPF may be associated with NAFLD, although more large prospective studies are needed. These findings emphasize the importance of minimizing the consumption of UPF to prevent NAFLD and other metabolic diseases among the general adult population. This systematic review and further prospective studies, epidemiological or interventional, can help physicians provide patients with evidence-based nutritional recommendations and will support policymakers in restricting the marketing of UPF as well as promoting affordable, healthy, and minimally processed foods.

Mystery of bisphenol F-induced nonalcoholic fatty liver disease-like changes: Roles of Drp1-mediated abnormal mitochondrial fission in lipid droplet deposition

As one of the major substitutes for bisphenol A (BPA), bisphenol F (BPF) has been widely used. Our previous study demonstrated that BPF exposure facilitates lipid droplet deposition in hepatic cells, contributing to nonalcoholic fatty liver disease (NAFLD)-like changes. However, the underlying mechanisms remain poorly understood. Here, with a metabolic cage system, we observed the perturbation of energy metabolism in mice treated with BPF. BPF obviously suppressed metabolic capacity, which manifested as decreased energy expenditure, low O2 consumption and CO2 levels in mice. Consistent with the in vivo results, a Seahorse XF Cell Mito Stress Test showed significant reductions in mitochondrial ATP production capacity, maximum respiratory capacity, and residual respiratory capacity after BPF treatment in an in vitro study. Electron microscopy revealed a striking increase in mitochondrial fission that was synchronous with excessive expression and activation of dynamin-related protein 1 (Drp1). Intriguingly, chemical inhibition of Drp1 by Mdivi-1 and/or silencing of Drp1 dramatically hampered mitochondrial fission and ameliorated BPF-induced lipid droplet deposition both in mouse liver and human hepatic cells. Mechanistically, mitochondrial dynamics imbalance played prominent roles in these processes, since suppression of Drp1 by chemical inhibition or knockdown substantially reversed BPF-induced mitochondrial fission and ameliorated the suppression of mitochondrial metabolism as well as excessive mitochondrial ROS, which was verified to be key to lipid droplet deposition. Collectively, the findings of the current study reveal previously unrecognized effects involving Drp1-mediated mitochondrial injury in BPF-induced lipid droplet deposition. Therefore, targeted intervention against mitochondrial dysfunction may be a promising therapeutic strategy for BPF-induced NAFLD-like changes.

Bisphenol A induces non-alcoholic fatty liver disease by promoting the O-GlcNAcylation of NLRP3

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease. The mechanism by which bisphenol A (BPA) promots NAFLD remains unclear. Palmitic acid (PA) and lipopolysaccharide (LPS) were used to simulate NAFLD in HepG2 cells in vitro. Total cholesterol (TC), triglyceride (TG) content, and lipid accumulation were measured to evaluate lipid metabolism. The caspase-1-stained cells and NLRP3 inflammasome-associated proteins were evaluated for pyroptosis. Western blot analysis was used to detect protein levels and co-immunoprecipitation (Co-IP) was used to detect the association between the proteins. Cycloheximide (CHX) treatment combined with western blot was performed to access protein stability. This data have shown that BPA induces lipid metabolism dysfunction and pyroptosis by upregulating O-GlcNAc transferase (OGT) level. NLRP3 directly interacts with OGT, and elevated OGT enhanced the stability of NLRP3 protein. BPA promoted OGT-mediated O-GlcNAcylation to stabilised NLRP3, thus accelerating NAFLD progress in vitro. Our study reveals that BPA, as an environmental factor, may be involved in the promotion of NAFLD, and that targeting NLRP3 and OGT may inhibit BPA's induction of NAFLD.

Mitigating the impact of bisphenol A exposure on mortality: Is diet the key? A cohort study based on NHANES

Bisphenol A (BPA) is a widespread environmental pollutant linked to detrimental effects on human health and reduced life expectancy following chronic exposure. This prospective cohort study aimed to examine the association between BPA exposure and mortality in American adults and to explore the potential mitigating effects of dietary quality on BPA-related mortality. This study utilized data from 8761 American adults in the 2003-2016 National Health and Nutrition Examination Survey (NHANES). Urinary BPA levels were employed to assess BPA exposure, and dietary quality was evaluated using the Healthy Eating Index-2015 (HEI-2015). All-cause, cardiovascular disease (CVD), and cancer mortality statuses were determined until December 31, 2019, resulting in a cumulative follow-up of 80,564 person-years. The results showed that the highest tertile of urinary BPA levels corresponded to a 36% increase in all-cause mortality and a 62% increase in CVD mortality compared to the lowest tertile. In contrast, the highest tertile of HEI-2015 scores was associated with a 29% reduction in all-cause mortality relative to the lowest tertile. Although no significant interaction was found between HEI-2015 scores and urinary BPA levels concerning mortality, the association between HEI-2015 scores and both all-cause and CVD mortality was statistically significant at low urinary BPA levels. Continuous monitoring of BPA exposure is crucial for evaluating its long-term adverse health effects. Improving dietary quality can lower all-cause mortality and decrease the risk of all-cause and CVD mortality at low BPA exposure levels. However, due to the limited protective effect of dietary quality against BPA exposure, minimizing BPA exposure remains a vital goal.

Modulatory effects of bisphenol A on the hepatic immune response

The liver is a primary line of defense for protection from external substances next to the intestinal barrier. As a result, the hepatic immune system plays a central role in liver pathophysiology. Bisphenol A (BPA) is one of the most common endocrine disrupting chemicals and is primarily metabolized in the liver. Due to its ability to bind to estrogen receptors, BPA is well known to possess estrogenic activity and disrupt reproductive functions. The phase I and Phase II metabolism reactions of BPA mainly occur in the liver with the help of enzymes including cytochrome P450 (CYP), uridine 5'-diphospho-glucuronosyltransferase-glucuronosyltransferases, sulfotransferases, and glutathione-S-transferases. Although the majority of BPA is excreted after conjugation by these enzymes, untransformed BPA induces the production of reactive oxygen species through disruption of the enzymatic complex CYP, lipid accumulation, mitochondrial dysfunction, endoplasmic reticulum stress and inflammatory injury in the liver. Moreover, it has been proposed to possess a potential immunomodulatory effect. Indeed, several in vivo and in vitro studies have reported that low doses of BPA increase the population of T cells with type 1 T helper (Th1), Th2, and Th17 cells. Although the current literature lacks clear evidence on the mechanisms by which BPA is involved in T cell mediated immune responses, recent multi-omics studies suggest that it may directly interact with the antigen processing and presentation pathways. In this review, we first discuss the metabolism of BPA in the liver, before exploring currently available data on its effects on liver injury. Finally, we review its modulatory effects on the hepatic immune response, as well as potential mechanisms. By conducting this review, we aim to improve understanding on the relationship between BPA exposure and immune-related liver injury, with a focus on the antigen processing and presentation pathway and T cell-mediated response in the liver.

Curcumin protects against bisphenol A-induced hepatic steatosis by inhibiting cholesterol absorption and synthesis in CD-1 mice

Curcumin is a polyphenol extracted from the rhizome of turmeric, and our previous research showed that curcumin inhibited cholesterol absorption and had cholesterol-lowering effect. Bisphenol A (BPA), a common plasticizer, is widely used in the manufacture of food packaging and is associated with non-alcoholic fatty liver disease (NAFLD). We hypothesized that curcumin could protect against BPA-induced hepatic steatosis by inhibiting cholesterol absorption and synthesis. Male CD-1 mice fed BPA-contaminated diet with or without curcumin for 24 weeks were used to test our hypothesis. We found that chronic low-dose BPA exposure significantly increased the levels of serum triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol and the contents of liver TG and TC, resulting in liver fat accumulation and hepatic steatosis while curcumin supplementation could alleviate BPA-induced dyslipidemia and hepatic steatosis. Moreover, the anti-steatosis and cholesterol-lowering effects of curcumin against BPA coincided with a significant reduction in intestinal cholesterol absorption and liver cholesterol synthesis, which was modulated by suppressing the expression of sterol regulatory element-binding protein-2 (SREBP-2), Niemann-Pick C1-like 1 (NPC1L1), and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) in the small intestine and liver. In addition, the expression levels of liver lipogenic genes such as liver X receptor alpha (LXRα), SREBP-1c, acetyl-CoA carboxylase 1 (ACC1), and ACC2 were also markedly down-regulated by curcumin. Overall, our findings indicated that curcumin inhibited BPA-induced intestinal cholesterol absorption and liver cholesterol synthesis by suppressing SREBP-2, NPC1L1, and HMGCR expression, subsequently reducing liver cholesterol accumulation and fat synthesis, thereby preventing hepatic steatosis and NAFLD.

Sex, Nutrition, and NAFLD: Relevance of Environmental Pollution

Non-alcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease and represents an increasing public health issue given the limited treatment options and its association with several other metabolic and inflammatory disorders. The epidemic, still growing prevalence of NAFLD worldwide cannot be merely explained by changes in diet and lifestyle that occurred in the last few decades, nor from their association with genetic and epigenetic risk factors. It is conceivable that environmental pollutants, which act as endocrine and metabolic disruptors, may contribute to the spreading of this pathology due to their ability to enter the food chain and be ingested through contaminated food and water. Given the strict interplay between nutrients and the regulation of hepatic metabolism and reproductive functions in females, pollutant-induced metabolic dysfunctions may be of particular relevance for the female liver, dampening sex differences in NAFLD prevalence. Dietary intake of environmental pollutants can be particularly detrimental during gestation, when endocrine-disrupting chemicals may interfere with the programming of liver metabolism, accounting for the developmental origin of NAFLD in offspring. This review summarizes cause-effect evidence between environmental pollutants and increased incidence of NAFLD and emphasizes the need for further studies in this field.

Re-evaluation of the risks to public health related to the presence of bisphenol A (BPA) in foodstuffs

In 2015, EFSA established a temporary tolerable daily intake (t-TDI) for BPA of 4 μg/kg body weight (bw) per day. In 2016, the European Commission mandated EFSA to re-evaluate the risks to public health from the presence of BPA in foodstuffs and to establish a tolerable daily intake (TDI). For this re-evaluation, a pre-established protocol was used that had undergone public consultation. The CEP Panel concluded that it is Unlikely to Very Unlikely that BPA presents a genotoxic hazard through a direct mechanism. Taking into consideration the evidence from animal data and support from human observational studies, the immune system was identified as most sensitive to BPA exposure. An effect on Th17 cells in mice was identified as the critical effect; these cells are pivotal in cellular immune mechanisms and involved in the development of inflammatory conditions, including autoimmunity and lung inflammation. A reference point (RP) of 8.2 ng/kg bw per day, expressed as human equivalent dose, was identified for the critical effect. Uncertainty analysis assessed a probability of 57-73% that the lowest estimated Benchmark Dose (BMD) for other health effects was below the RP based on Th17 cells. In view of this, the CEP Panel judged that an additional uncertainty factor (UF) of 2 was needed for establishing the TDI. Applying an overall UF of 50 to the RP, a TDI of 0.2 ng BPA/kg bw per day was established. Comparison of this TDI with the dietary exposure estimates from the 2015 EFSA opinion showed that both the mean and the 95th percentile dietary exposures in all age groups exceeded the TDI by two to three orders of magnitude. Even considering the uncertainty in the exposure assessment, the exceedance being so large, the CEP Panel concluded that there is a health concern from dietary BPA exposure.

Serum glycolipids mediate the relationship of urinary bisphenols with NAFLD: analysis of a population-based, cross-sectional study

BACKGROUND

Bisphenol A (BPA) and its substitutes bisphenol S (BPS) and bisphenol F (BPF) are endocrine-disrupting chemicals widely used in consumer products, which have been proposed to induce various human diseases. In western countries, one of the most common liver diseases is non-alcoholic fatty liver disease (NAFLD). However, studies on the associations of the three bisphenols with NAFLD in human beings are scarce.

METHODS

We included 960 participants aged ≥ 20 years from the NHANES 2013-16 who had available data on levels of urinary BPA, BPS and BPF. The hepatic steatosis index (HSI) > 36 was used to predict NAFLD. Logistic regression analysis and mediation effect analysis were used to evaluate the associations among bisphenols, glycolipid-related markers and NAFLD.

RESULTS

A total of 540 individuals (56.3%) were diagnosed with NAFLD, who had higher concentrations of BPA and BPS but not BPF than those without NAFLD. An increasing trend in NAFLD risks and HSI levels was observed among BPA and BPS tertiles (p for trend < 0.05). After adjustment for confounders, elevated levels of BPA or BPS but not BPF were significantly associated with NAFLD. The odds ratio for NAFLD was 1.581 (95% confidence intervals [CI]: 1.1-2.274, p = 0.013) comparing the highest with the lowest tertile of BPA and 1.799 (95%CI: 1.2462.597, p = 0.002) for BPS. Mediation effect analysis indicated that serum high-density lipoprotein cholesterol and glucose had a mediating effect on the relationships between bisphenols and NAFLD.

CONCLUSIONS

The present study showed that high exposure levels of BPA and BPS increased NAFLD incidence, which might be mediated through regulating glycolipids metabolism. Further studies on the role of bisphenols in NAFLD are warranted.

Combined effect of polystyrene microplastics and bisphenol A on the human embryonic stem cells-derived liver organoids: The hepatotoxicity and lipid accumulation

Human are exposed to microplastics (MP) via inhalation or ingestion daily and inevitably. The liver is an important target organ of MP. Bisphenol A (BPA) is one of commonly used plasticizers. It is added in plastics, but also generally detected in the biological samples of human beings. However, the combined toxic effect of MP and BPA on human liver is unclear. In this study, a novel 3D in vitro model, the liver organoid (LO) derived from human-pluripotent stem cells, has been utilized to explore the 1 μm polystyrene (PS)-induced hepatotoxicity with BPA individually and jointly. Conclusively, all the changes in the cytotoxicity, cellular and molecular makers regarding the energy supplement, hepatic injury, oxidative stress, inflammatory response, disruption in the lipid accumulation, as well as epigenetics regulation induced by BPA or PS on the LOs individually were comparable to previous study. The BPA levels in the culture medium were declined by the added PS. The combined adverse effect of PS and BPA on the LOs was identified to be synergistic upon deteriorated hepatotoxicity and interfered the gene panels related to multiple processes of lipid metabolism, together with the proteins of HNF4A, CD36, ACC1, CPT1A, CYP2E1, ERα and ERβ. Specifically, PS didn't change the ERα or ERβ individually, but when the LOs were co-exposed to PS and BPA, the ERα further elevated significantly and synergistically. Our findings highlight the metabolic-related health risk due to co-exposure to MP and BPA, even at low-doses equivalent to human internal exposure level. Based on these findings, the potential adverse outcome pathway related to PS and BPA singly and jointly were proposed, predicting two possible outcomes to be hepatic steatosis. Moreover, the ERα and HNF4A were proposed to be potential candidate markers to investigate the "vector-like effect" of PS in the present of BPA.

Bisphenol A enhances apoptosis, fibrosis, and biochemical fluctuations in the liver of adult male rats with possible regression after recovery

Bisphenol A (BPA) is an environmental contaminant that might be harmful. Human exposure to BPA can occur during the fetal and postnatal periods and extends throughout life. This study aimed to estimate the effects of oral administration of BPA on rat liver and assess the possibility of recovery after cessation. Adult male albino rats were orally administered with BPA (50 mg/kg body weight) for 8 weeks, and then one group was left to recover for 4 weeks. Histological, immunohistochemical, biochemical, and quantitative real-time polymerase chain reaction assessments were performed. Loss of hepatic architecture, vascular dilatation congestion, and exudation, as well as cellular vacuolation, fat accumulation, and pyknotic nuclei were detected. Furthermore, inflammatory infiltration, localized metaplasia, and excessive collagen deposition in the portal triad were observed. Expression of Bcl-2-associated X protein and transforming growth factor beta 1 was prominent, denoting apoptosis and fibrosis. After the administration of BPA, serum levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bilirubin, cholesterol, triglycerides, and low-density lipoproteins were enhanced. Additionally, total protein, albumin, and high-density lipoproteins decreased. After a recovery for 4 weeks, hepatic cellular and vascular pathologies returned to normal, except for some inflammatory infiltration. Regarding biochemical affection, most of the parameters were directed toward normal during recovery. However, most of them were still significantly different from controls. This explored BPA hepatotoxicity from structural and functional aspects, and the possible spontaneous reversibility was confirmed. However, the precise mechanisms underlying hepatotoxicity or recovery need more in-depth investigations.

Endocrine disrupting chemicals: A promoter of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disorder. With the improvement in human living standards, the prevalence of NAFLD has been increasing in recent years. Endocrine-disrupting chemicals (EDCs) are a class of exogenous chemicals that simulate the effects of hormones in the body. There has been growing evidence regarding the potential effects of EDCs on liver health, especially in NAFLD. This paper aims to summarize the major EDCs that contribute to the growing burden of NAFLD and to raise public awareness regarding the hazards posed by EDCs with the objective of reducing the incidence of NAFLD.

The Role of Cholesterol in the Interaction of the Lipid Monolayer with the Endocrine Disruptor Bisphenol-A

Among pollutants of emerging concern, endocrine disruptors (ED) have been shown to cause side effects in humans and animals. Bisphenol-A (BPA) is an ED by-product of the plastic industry and one of the chemicals with the highest volume produced yearly. Here, we studied the role of cholesterol in the BPA exposure effects over membrane models. We used Langmuir films of both neat lipid DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) and cholesterol (Chol) and a binary mixture containing DPPC/Chol, exposing it to BPA. We evaluate changes in the π-A isotherms and the PM–IRRAS (polarization modulation–infrared reflection adsorption spectroscopy) spectra. BPA exposure induced changes in the DPPC and Chol neat monolayers, causing mean molecular area expansion and altering profiles. However, at high surface pressure, the BPA was expelled from the air–water interface. For the DPPC/Chol mixture, BPA caused expansion throughout the whole compression, indicating that BPA is present at the monolayer interface. The PM–IRRAS analysis showed that BPA interacted with the phosphate group of DPPC through hydrogen bonding, which caused the area’s expansion. Such evidence might be biologically relevant to better understand the mechanism of action of BPA in cell membranes once phosphatidylcholines and Chol are found in mammalian membranes.

Association between urinary environmental phenols and the prevalence of cardiovascular diseases in US adults

Environmental phenols, as endocrine disruptors, are used widely in personal care and consumer products. However, few studies have examined the association between phenol exposure, including bisphenol A (BPA), benzophenone-3 (BP-3), and triclosan, and the prevalence of cardiovascular diseases (CVD). This cross-sectional study utilized data from the National Health and Nutrition Examination Survey (2003-2012). Urinary BPA, BP-3, and triclosan were measured with liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The CVD was defined as a composite of 5 self-reported cardiovascular outcomes, including congestive heart failure, coronary heart disease, angina pectoris, heart attack or stroke. Multivariable logistic regression models were used to examine the association between phenols and the prevalence of CVD. A total of 8164 participants were enrolled, and 740 (9.1%) were diagnosed of CVD. The average levels of BPA, BP-3, and triclosan concentrations were 3.38, 202.63, and 99.27 ng/mL respectively. Per 1-unit increasement in log-transformed urinary BPA was associated with increased risk of CVD after adjusting all covariates (odds ratio [OR] 1.09, 95% confidence interval [CI] 1.01 to 1.18, P < 0.05). Compared with the lowest quartile (< 0.9), the multivariable-adjusted OR was 1.30 (1.03 to 1.65, P < 0.05) in the highest quartile (> 3.8). Restricted spline models confirmed that the association between BPA and the risk of CVD was non-linear (P = 0.045). Only BPA was associated with the risk of CVD, following a J-curve shaped relationship.

Bisphenol A Coupled with a High-Fat Diet Promotes Hepatosteatosis through Reactive-Oxygen-Species-Induced CD36 Overexpression

Bisphenol A (BPA) is an endocrine-disrupting chemical that affects lipid metabolism and contributes to non-alcoholic fatty liver disease (NAFLD). The mechanism of BPA exposure in hepatic lipid accumulation and its potential effect on NAFLD remain unclear. This study investigated the effect of BPA-exposure-induced hepatic lipid deposition on the pathology of NAFLD and its underlying mechanism in vitro and in vivo. BPA increased intracellular reactive oxygen species (ROS) levels, and promoted fatty acid uptake through upregulation of a free fatty acid uptake transporter, cluster of differentiation 36 (CD36), in HUH-7 cells. Additionally, C57BL/6 mice administered a high-fat/high-cholesterol/high-cholic acid diet (HFCCD) and BPA (50 mg/kg body weight) for 8 weeks developed a steatohepatitis-like phenotype, characterized by alpha-smooth muscle actin (α-SMA, an indicator of hepatic fibrosis) and cleaved caspase 3 (an indicator of apoptosis) in hepatic tissue; moreover, they had a higher oxidative stress index of 8-hydroxydeoxyguanosine (8-OHdG) in liver tissue compared to the control group. Treatment with ROS scavenger n-acetylcysteine (NAC) ameliorated BPA-mediated HFCCD-induced lipid accumulation and steatohepatitis in the livers of treated mice. Our study indicates that BPA acts synergistically to increase hepatic lipid uptake and promote NAFLD development by stimulating ROS-induced CD36 overexpression.

Silymarin is an ally against insulin resistance: A review

Silymarin is obtained from the Milk thistle plant Silybum marianum and has been used over the centuries to treat principally liver disease, although it has also been studied for its beneficial effects in cardioprotection, neuroprotection, immune modulation, and cancer among others. Importantly, silymarin's active component silybin is a flavonolignan that exhibits different activities such as; scavenger, anti-oxidant, anti-inflammatory, and recently revealed, insulin-sensitizing properties which have been explored in clinical trials in patients with insulin resistance. In this review, we summarize the most relevant research of silymarin's effect on lipid and carbohydrate metabolism, focusing the attention on insulin resistance, which is well known to play a crucial role in metabolic disease progression.

Cell Models and Omics Techniques for the Study of Nonalcoholic Fatty Liver Disease: Focusing on Stem Cell-Derived Cell Models

Nonalcoholic fatty liver disease (NAFLD) is now the leading cause of chronic liver disease in western countries. The molecular mechanisms leading to NAFLD are only partially understood, and effective therapeutic interventions are clearly needed. Therefore, preclinical research is required to improve knowledge about NAFLD physiopathology and to identify new therapeutic targets. Primary human hepatocytes, human hepatic cell lines, and human stem cell-derived hepatocyte-like cells exhibit different hepatic phenotypes and have been widely used for studying NAFLD pathogenesis. In this paper, apart from employing the different in vitro cell models for the in vitro assessment of NAFLD, we also reviewed other approaches (metabolomics, transcriptomics, and high-content screening). We aimed to summarize the characteristics of different cell types and methods and to discuss their major advantages and disadvantages for NAFLD modeling.

PNPLA3, TM6SF2, and MBOAT7 Influence on Nutraceutical Therapy Response for Non-alcoholic Fatty Liver Disease: A Randomized Controlled Trial

Introduction: PNPLA3, TM6SF2, and MBOAT7 genes play a crucial role in non-alcoholic fatty liver disease (NAFLD) development and worsening. However, few data are available on their treatment response influence. The aim of this trial is to explore the effect derived from silybin-phospholipids complex (303 mg of silybin-phospholipids complex, 10 μg of vitamin D, and 15 mg of vitamin E twice a day for 6 months) oral administration in NAFLD patients carrying PNPLA3-rs738409, TM6SF2-rs58542926, or MBOAT7-rs641738 genetic variants. Materials and Methods: In all, 92 biopsy-proven NAFLD patients were grouped in 30 NAFLD wild type controls, 30 wild type treated patients, and 32 mutated treated ones. We assessed glycemia (FPG), insulinemia, HOMA-IR, aspartate and alanine aminotransferases (AST, ALT), C-reactive protein (CRP), thiobarbituric acid reactive substance (TBARS), stiffness, controlled attenuation parameter (CAP), dietary daily intake, and physical activity at baseline and end of treatment. Results: The wild-type treated group showed a significant improvement of FPG, insulinemia, HOMA-IR, ALT, CRP, and TBARS (p < 0.05), whereas no improvements were recorded in the other two study groups. NAFLD wild type treated patients showed higher possibilities of useful therapeutic outcome (p < 0.01), obtained from the prescribed therapeutic regimen, independently from age, sex, comorbidities, medications, CAP, and stiffness in comparison to the mutated group. Discussion: The assessed mutations are independently associated with no response to a silybin-based therapeutic regimen and could be considered as useful predictive markers in this context. Clinical Trial Registry Number: www.ClinicalTrials.gov, identifier: NCT04640324.

The association between urinary bisphenol A levels and nonalcoholic fatty liver disease in Korean adults: Korean National Environmental Health Survey (KoNEHS) 2015-2017

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is becoming a global health problem. Bisphenol A (BPA), one of most widely used environmental chemicals, is suspected to be a contributor to the development NAFLD. This study was performed to examine the relationship between human BPA levels and risk of NAFLD.

METHODS

The data (n = 3476 adults: 1474 men and 2002 women) used in this study were obtained from the Korean National Environmental Health Survey III (2015-2017). BPA levels were measured in urine samples. NAFLD was defined using hepatic steatosis index after exclusion of other causes of hepatic diseases.

RESULTS

There was a significant linear relationship between the elevated urinary BPA concentrations and risk of NAFLD. In a univariate analysis, odds ratio (OR) of the highest quartile of urinary BPA level was 1.47 [95% confidence interval (CI) 1.11-1.94] compared to the lowest quartile. After adjusted with covariates, the ORs for NAFLD in the third and fourth quartiles were 1.31 [95% CI 1.03-1.67] and 1.32 [95% CI 1.03-1.70], respectively.

CONCLUSIONS

Urinary BPA levels are positively associated with the risk of NAFLD in adults. Further experimental studies are needed to understand the molecular mechanisms of BPA on NAFLD prevalence.

Human biomonitoring initiative (HBM4EU): Human biomonitoring guidance values (HBM-GVs) derived for bisphenol A

The "European Human Biomonitoring Initiative" (HBM4EU) derives human biomonitoring guidance values (HBM-GVs) for the general population (HBM-GV_GenPop) and/or for occupationally exposed adults (HBM-GV_Worker) for several priority substances and substance groups as identified by policy makers, scientists and stakeholders at EU and national level, including bisphenol A (BPA). Human exposure to BPA is widespread and of particular concern because of its known endocrine-disrupting properties. Unlike the conjugated forms of BPA circulating in the body, free BPA is known to interact with the nuclear estrogen receptors. Because free BPA is considered to be more toxicologically active than the conjugated forms (e.g. BPA-glucuronide (BPA-G) and BPA-sulfate (BPA-S)), its measurement in blood provides the superior surrogate of the biologically effective dose. However, considering the difficulty of implementing blood sampling in large HBM cohorts, as well as the current analytical capacities complying with the quality assurance (QA)/quality control (QC) schemes, total BPA in urine (i.e. the sum of free and conjugated forms of BPA measured after an hydrolysis of phase II metabolites) was retained as the relevant exposure biomarker for BPA. HBM-GV_GenPop for total BPA in urine of 230 µg/L and 135 µg/L for adults and children, respectively, were developed on the basis of toxicological data. To derive these values, the concentrations of urinary total BPA consistent with a steady-state exposure to the temporary Tolerable Daily Intake (t-TDI) of 4 µg/kg bw/day set in 2015 by the European Food Safety Authority (EFSA) were estimated. The BPA human physiologically-based pharmacokinetic (PBPK) model developed by Karrer et al. (2018) was used, assuming an oral exposure to BPA at the t-TDI level averaged over 24 h. Dermal uptake of BPA is suspected to contribute substantially to the total BPA body burden, which in comparison with the oral route, is generating a higher ratio of free BPA to total BPA in blood. Therefore, an alternative approach for calculating the HBM-GV_GenPop according to the estimated relative contributions of both the oral and dermal routes to the global BPA exposure is also discussed. Regarding BPA exposure at the workplace, the steady-state concentration of urinary total BPA was estimated after a dermal uptake of BPA that would generate the same concentration of free BPA in plasma (considered as the bioactive form) as would a 24 h-averaged intake to the European Chemicals Agency (ECHA)'s oral DNEL of 8 µg BPA/kg bw/day set for workers. The predicted concentration of urinary total BPA at steady-state is equivalent to, or exceeds the 95th percentile of total BPA in urine measured in different European HBM studies conducted in the general population. Thus, no HBM-GV_Worker was proposed, as the high background level of BPA coming from environmental exposure - mostly through food intake - is making the discrimination with the occupational exposure to BPA difficult.

Nutrigenomics and Nutrigenetics in Metabolic- (Dysfunction) Associated Fatty Liver Disease: Novel Insights and Future Perspectives

Metabolic- (dysfunction) associated fatty liver disease (MAFLD) represents the predominant hepatopathy and one of the most important systemic, metabolic-related disorders all over the world associated with severe medical and socio-economic repercussions due to its growing prevalence, clinical course (steatohepatitis and/or hepatocellular-carcinoma), and related extra-hepatic comorbidities. To date, no specific medications for the treatment of this condition exist, and the most valid recommendation for patients remains lifestyle change. MAFLD has been associated with metabolic syndrome; its development and progression are widely influenced by the interplay between genetic, environmental, and nutritional factors. Nutrigenetics and nutrigenomics findings suggest nutrition’s capability, by acting on the individual genetic background and modifying the specific epigenetic expression as well, to influence patients’ clinical outcome. Besides, immunity response is emerging as pivotal in this multifactorial scenario, suggesting the interaction between diet, genetics, and immunity as another tangled network that needs to be explored. The present review describes the genetic background contribution to MAFLD onset and worsening, its possibility to be influenced by nutritional habits, and the interplay between nutrients and immunity as one of the most promising research fields of the future in this context.

Immunity as Cornerstone of Non-Alcoholic Fatty Liver Disease: The Contribution of Oxidative Stress in the Disease Progression

Non-alcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of metabolic syndrome and has become the major cause of chronic liver disease, especially in western countries. NAFLD encompasses a wide spectrum of hepatic histological alterations, from simple steatosis to steatohepatitis and cirrhosis with a potential development of hepatocellular carcinoma. Non-alcoholic steatohepatitis (NASH) is characterized by lobular inflammation and fibrosis. Several studies reported that insulin resistance, redox unbalance, inflammation, and lipid metabolism dysregulation are involved in NAFLD progression. However, the mechanisms beyond the evolution of simple steatosis to NASH are not clearly understood yet. Recent findings suggest that different oxidized products, such as lipids, cholesterol, aldehydes and other macromolecules could drive the inflammation onset. On the other hand, new evidence indicates innate and adaptive immunity activation as the driving force in establishing liver inflammation and fibrosis. In this review, we discuss how immunity, triggered by oxidative products and promoting in turn oxidative stress in a vicious cycle, fuels NAFLD progression. Furthermore, we explored the emerging importance of immune cell metabolism in determining inflammation, describing the potential application of trained immune discoveries in the NASH pathological context.

Autophagy mediates perfluorooctanoic acid-induced lipid metabolism disorder and NLRP3 inflammasome activation in hepatocytes

Perfluorooctanoic acid (PFOA) has applications in numerous industrial products and is an industrial waste that is persistently present in the environment. Exposure to PFOA results in nonalcoholic fatty liver disease (NAFLD). However, the underlying mechanisms remain unclear. In this study, male C57BL/6 mice were exposed to PFOA (1 mg/kg/day) for 4 weeks to evaluate the effect of PFOA, and the human liver cell line (L-02) was used to observe the direct effect of PFOA in vitro. After PFOA exposure, the expression of genes related to hepatic lipogenesis, the NLRP3 inflammasome, and autophagy were measured. We found that exposure to PFOA induced lipid accumulation and stimulated lipogenesis in both mouse livers and L-02 cells. In addition, increased NLRP3 aggregation and enhanced production of IL-1β occurred after PFOA treatment. We also found that PFOA exposure induced autophagosome formation and p62 accumulation, indicating blockage of autophagic flux. Rapamycin alleviated PFOA-induced lipid accumulation and NLRP3 inflammasome activation by activating autophagic flux. Conversely, chloroquine, an autophagic flux inhibitor, exacerbated PFOA-induced lipid accumulation and NLRP3 inflammasome activation. Collectively, these results provide evidence to show that PFOA-induced blockade of autophagic flux causes an increase in lipid synthesis and inflammation in vivo and in vitro.

Bisphenol A exposure induces gut microbiota dysbiosis and consequent activation of gut-liver axis leading to hepatic steatosis in CD-1 mice

Interactions between the intestine and the liver, the so-called 'gut-liver axis', play a crucial role in the onset of hepatic steatosis and non-alcoholic fatty liver disease. However, not much is known about the impact of environmental pollutants on the gut-liver axis and consequent hepatic steatosis. Bisphenol A (BPA), a widely used plasticiser, is an important environmental contaminant that affects gut microbiota. We hypothesised that BPA induces hepatic steatosis by promoting gut microbiota dysbiosis and activating the gut-liver axis. In this study, male CD-1 mice were fed with diet containing BPA (50 μg/kg body weight/day) for 24 weeks. Dietary exposure to BPA increased lipid contents and fat accumulation in the liver. Analysis of 16 S rRNA gene sequencing revealed that the diversity of gut microbiota reduced and the composition of gut microbiota was altered in the BPA-fed mice. Further, the abundance of Proteobacteria, a marker of dysbacteria, increased, whereas the abundance of Akkermansia, a gut microbe associated with increased gut barrier function and reduced inflammation, markedly decreased. Expression levels of intestinal tight junction proteins (zona occludens-1 and occludin) also decreased drastically, leading to increased intestinal permeability and elevated levels of endotoxins. Furthermore, BPA up-regulated the expression of Toll-like receptor 4 (TLR4) and phosphorylation of nuclear factor-kappa B (NF-κB) in the liver and increased the production of inflammatory cytokines, including interleukin-1β, interleukin-18, tumour necrosis factor-α, and interleukin-6. Take together, our work indicated that dietary intake of BPA induced hepatic steatosis, and this was closely related to dysbiosis of gut microbiota, elevated endotoxin levels, and increased liver inflammation through the TLR4/NF-κB pathway.

Liver Steatosis, Gut-Liver Axis, Microbiome and Environmental Factors. A Never-Ending Bidirectional Cross-Talk

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing worldwide and parallels comorbidities such as obesity, metabolic syndrome, dyslipidemia, and diabetes. Recent studies describe the presence of NAFLD in non-obese individuals, with mechanisms partially independent from excessive caloric intake. Increasing evidences, in particular, point towards a close interaction between dietary and environmental factors (including food contaminants), gut, blood flow, and liver metabolism, with pathways involving intestinal permeability, the composition of gut microbiota, bacterial products, immunity, local, and systemic inflammation. These factors play a critical role in the maintenance of intestinal, liver, and metabolic homeostasis. An anomalous or imbalanced gut microbial composition may favor an increased intestinal permeability, predisposing to portal translocation of microorganisms, microbial products, and cell wall components. These components form microbial-associated molecular patterns (MAMPs) or pathogen-associated molecular patterns (PAMPs), with potentials to interact in the intestine lamina propria enriched in immune cells, and in the liver at the level of the immune cells, i.e., Kupffer cells and stellate cells. The resulting inflammatory environment ultimately leads to liver fibrosis with potentials to progression towards necrotic and fibrotic changes, cirrhosis. and hepatocellular carcinoma. By contrast, measures able to modulate the composition of gut microbiota and to preserve gut vascular barrier might prevent or reverse NAFLD.

Antifibrotic effect of curcumin, N-acetyl cysteine and propolis extract against bisphenol A-induced hepatotoxicity in rats: Prophylaxis versus co-treatment

AIMS

Bisphenol A (BPA) has been shown to induce liver fibrosis in rodents. Therefore, this study examined the protective effect of a triple combination of curcumin (Cur), N-acetyl cysteine (NAC) and propolis (Prp) extract against BPA-induced hepatic fibrosis.

METHODS

100 Wistar male rats were equally assigned into 10 groups; one group was designated as control. 10 rats were gavaged with BPA (50 mg/kg/day) for 8 wk and left un-treated (BPA group). The remaining 80 rats were divided into 8 groups, distributed in 2 models. Protective model: rats were daily co-treated with BPA and Cur (100 mg/kg, p.o) or NAC (150 mg/kg, p.o) or Prp (200 mg/kg, p.o) or their combination for 8 wk. Preventive model: rats were daily treated with Cur or NAC or Prp or their combination for 4 wk before BPA administration and then in the same manner as protective model.

KEY FINDINGS

Current treatment interventions significantly alleviated BPA-induced hepatic damage and fibrosis. They also restored pro-oxidant/antioxidant balance, shifted cytokine balance towards the anti-inflammatory side, decreasing interleukin-1β/interleukin-10 ratio. Moreover, these compounds seem to exert anti-apoptotic effects by increasing the immunoexpression of B-cell lymphoma 2 in hepatocytes and decreasing hepatic caspase-3 content. Finally, they ameliorated extracellular matrix turn over through down-regulation of matrix metalloproteinase-9 and up-regulation of tissue inhibitor of matrix metalloproteinase-2 genetic expression.

SIGNIFICANCE

Current treatments guarded against BPA-induced hepatic fibrosis due to their antioxidant, anti-inflammatory and anti-apoptotic properties, decreasing extracellular matrix turnover. Interestingly, the triple therapy provided hepatoprotection superior to monotherapy. Besides, prophylactic and concurrent treatments seem to be more effective than concurrent treatments.

Bisphenols and Oxidative Stress Biomarkers-Associations Found in Human Studies, Evaluation of Methods Used, and Strengths and Weaknesses of the Biomarkers

Bisphenols, particularly bisphenol A (4,4'-(hexafluoroisopropylidene)-diphenol) (BPA), are suspected of inducing oxidative stress in humans, which may be associated with adverse health outcomes. We investigated the associations between exposure to bisphenols and biomarkers of oxidative stress in human studies over the last 12 years (2008‒2019) related to six health endpoints and evaluated their suitability as effect biomarkers. PubMed database searches identified 27 relevant articles that were used for data extraction. In all studies, BPA exposure was reported, whereas some studies also reported other bisphenols. More than a dozen different biomarkers were measured. The most frequently measured biomarkers were 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-OHdG), 8-iso-prostaglandin F2α (8-isoprostane) and malondialdehyde (MDA), which almost always were positively associated with BPA. Methodological issues were reported for MDA, mainly the need to handle samples with caution to avoid artefact formation and its measurements using a chromatographic step to distinguish it from similar aldehydes, making some of the MDA results less reliable. Urinary 8-OHdG and 8-isoprostane can be considered the most reliable biomarkers of oxidative stress associated with BPA exposure. Although none of the biomarkers are considered BPA- or organ-specific, the biomarkers can be assessed repeatedly and non-invasively in urine and could help to understand causal relationships.

The Bisphenol A Induced Oxidative Stress in Non-Alcoholic Fatty Liver Disease Male Patients: A Clinical Strategy to Antagonize the Progression of the Disease

Introduction: Bisphenol A (BPA) exposure has been correlated to non-alcoholic fatty liver disease (NAFLD) development and progression. We investigated, in a clinical model, the effects of the administration of 303 mg of silybin phospholipids complex, 10 μg of vitamin D, and 15 mg of vitamin E (RealSIL, 100D, IBI-Lorenzini, Aprilia, Italy) in male NAFLD patients exposed to BPA on metabolic, hormonal, and oxidative stress-related parameters. Methods: We enrolled 32 male patients with histologic diagnosis of NAFLD and treated them with Realsil 100D twice a day for six months. We performed at baseline clinical, biochemical, and food consumption assessments as well as the evaluation of physical exercise, thiobarbituric acid reactive substances (TBARS), plasmatic and urinary BPA and estrogen levels. The results obtained were compared with those of healthy control subjects and, in the NAFLD group, between baseline and the end of treatment. Results: A direct proportionality between TBARS levels and BPA exposure was shown (p < 0.0001). The therapy determined a reduction of TBARS levels (p = 0.011), an improvement of alanine aminotransferase, aspartate aminotransferase, insulinemia, homeostatic model assessment insulin resistance, C reactive protein, tumor necrosis factor alpha (p < 0.05), an increase of conjugated BPA urine amount, and a reduction of its free form (p < 0.0001; p = 0.0002). Moreover, the therapy caused an increase of plasmatic levels of the native form of estrogens (p = 0.03). Conclusions: We highlighted the potential role of BPA in estrogen oxidation and oxidative stress in NAFLD patients. The use of Realsil 100D could contribute to fast BPA detoxification and to improve cellular antioxidant power, defending the integrity of biological estrogen-dependent pathways.

The effects of melatonin on possible damage that will occur on adipocytokines and liver tissue by coadministration of fructose and bisphenol a (BPA)

BPA, one of the environmental endocrine disruptors, and fructose, reason of liver steatosis which is frequently encountered in the daily diet, contribute to the formation of metabolic syndrome (MetS). This study examines the possible effects of concurrent fructose and BPA administration on MetS and determines the effects of melatonin on this process. In the seven identified groups, a total of forty-two adult male Sprague Dawley rats were treated by following fructose, BPA, and melatonin amounts, separately and together: group 1 (control), group 2 (10% aqueous fructose), group 3 (25 mg/kg BPA), group 4 (10% fructose + 25 mg/kg BPA), group 5 (10% fructose + 20 mg/kg melatonin), group 6 (25 mg/kg BPA + 20 mg/kg melatonin), and group 7 (10% fructose + 25 mg/kg BPA + 20 mg/kg melatonin). At the end of 60 days, histochemical, immunohistochemical, and biochemical procedures were performed on liver tissue. As a result, it was seen that BPA and fructose + BPA induced morphological alteration and inflammation and increased intracellular lipid quantity and amount of collagen and reticular fibers. The percentage of apoptotic liver cells stained by annexin V-FITC/PI was lower in group 7 compared to the group 4 (p < 0,001) and also in group 6 compared to the group 3 (p = 0.014). Both BPA and fructose application caused an increase in lipid peroxidation level due to the increase of oxidative stress. Application of melatonin induced antioxidant enzyme activity and reduced lipid peroxidation level. Our results indicate that fructose and BPA administration triggered the formation of MetS, whereas melatonin healed these variations, although not entirely.

In utero Bisphenol A Exposure Is Linked with Sex Specific Changes in the Transcriptome and Methylome of Human Amniocytes

CONTEXT

Prenatal exposure to bisphenol A (BPA) is linked to obesity and diabetes but the molecular mechanisms driving these phenomena are not known. Alterations in deoxyribonucleic acid (DNA) methylation in amniocytes exposed to BPA in utero represent a potential mechanism leading to metabolic dysfunction later in life.

OBJECTIVE

To profile changes in genome-wide DNA methylation and expression in second trimester human amniocytes exposed to BPA in utero.

DESIGN

A nested case-control study was performed in amniocytes matched for offspring sex, maternal race/ethnicity, maternal age, gestational age at amniocentesis, and gestational age at birth. Cases had amniotic fluid BPA measuring 0.251 to 23.74 ng/mL. Sex-specific genome-wide DNA methylation analysis and RNA-sequencing (RNA-seq) were performed to determine differentially methylated regions (DMRs) and gene expression changes associated with BPA exposure. Ingenuity pathway analysis was performed to identify biologically relevant pathways enriched after BPA exposure. In silico Hi-C analysis identified potential chromatin interactions with DMRs.

RESULTS

There were 101 genes with altered expression in male amniocytes exposed to BPA (q < 0.05) in utero, with enrichment of pathways critical to hepatic dysfunction, collagen signaling and adipogenesis. Thirty-six DMRs were identified in male BPA-exposed amniocytes and 14 in female amniocyte analysis (q < 0.05). Hi-C analysis identified interactions between DMRs and 24 genes with expression changes in male amniocytes and 12 in female amniocytes (P < 0.05).

CONCLUSION

In a unique repository of human amniocytes exposed to BPA in utero, sex-specific analyses identified gene expression changes in pathways associated with metabolic disease and novel DMRs with potential distal regulatory functions.

Could phthalates exposure contribute to the development of metabolic syndrome and liver disease in humans?

In the study, 305 patients of both genders were enrolled and divided into three groups: obese (BMI > 30 kg/m²), patients who were diagnosed type 2 diabetes mellitus (T2DM), and control, normal weight healthy volunteers. At least one of ten different phthalate metabolites was determined in the urine samples of 49.84% all enrolled participants. In the obese subgroup, the sum of all urinary phthalate metabolites was positively associated with TG levels (p = 0.031) together with derived TC/HDL and TG/HDL ratios (p = 0.023 and 0.015), respectively. Urinary MEP concentration was positively correlated with the HOMA-IR in T2DM subgroup (p = 0.016) while in the control subgroup, log₁₀MEP levels were negatively correlated with total cholesterol (p = 0.0051), and LDL serum levels (p = 0.0015), respectively. Also, in the control subgroup, positive linear correlations between urinary log₁₀MEP levels and TyG and TYG-BMI values (p = 0.028 and p = 0.027), respectively, were determined. Urinary MEHP levels were associated with glucose serum levels (p = 0.02) in T2DM subgroup, while in the control HDL values were negatively associated with log₁₀MEHP (p = 0.0035). Healthy volunteers exposed to phthalates had elevated AST levels in comparison to non-exposed ones (p = 0.023). In control subgroup, ALT and AST values were increased (p = 0.02 and p = 0.01, respectively) in MEP exposed while GGT levels were enhanced (p = 0.017) in MEHP exposed in comparison with non-exposed. Combined phthalates influence on glucose and lipid metabolism may increase the possibility for NAFLD and insulin resistance development among exposed individuals.

Evaluation of the Effect Derived from Silybin with Vitamin D and Vitamin E Administration on Clinical, Metabolic, Endothelial Dysfunction, Oxidative Stress Parameters, and Serological Worsening Markers in Nonalcoholic Fatty Liver Disease Patients

Nowadays, the nonalcoholic fatty liver disease represents the main chronic liver disease in the Western countries, and the correct medical therapy remains a big question for the scientific community. The aim of our study was to evaluate the effect derived from the administration for six months of silybin with vitamin D and vitamin E (RealSIL 100D®) on metabolic markers, oxidative stress, endothelial dysfunction, and worsening of disease markers in nonalcoholic fatty liver disease patients. We enrolled 90 consecutive patients with histological diagnosis of nonalcoholic fatty liver disease and 60 patients with diagnosis of reflux disease (not in therapy) as healthy controls. The nonalcoholic fatty liver disease patients were randomized into two groups: treated (60 patients) and not treated (30 patients). We performed a nutritional assessment and evaluated clinical parameters, routine home tests, the homeostatic model assessment of insulin resistance, NAFLD fibrosis score and fibrosis-4, transient elastography and controlled attenuation parameter, thiobarbituric acid reactive substances, tumor necrosis factor α, transforming growth factor β, interleukin-18 and interleukin-22, matrix metalloproteinase 2, epidermal growth factor receptor, insulin growth factor-II, cluster of differentiation-44, high mobility group box-1, and Endocan. Compared to the healthy controls, the nonalcoholic fatty liver disease patients had statistically significant differences for almost all parameters evaluated at baseline (p < 0.05). Six months after the baseline, the proportion of nonalcoholic fatty liver disease patients treated that underwent a statistically significant improvement in metabolic markers, oxidative stress, endothelial dysfunction, and worsening of disease was greater than not treated nonalcoholic fatty liver disease patients (p < 0.05). Even more relevant results were obtained for the same parameters by analyzing patients with a concomitant diagnosis of metabolic syndrome (p < 0.001). The benefit that derives from the use of RealSIL 100D could derive from the action on more systems able to advance the pathology above all in that subset of patients suffering from concomitant metabolic syndrome.

Chemical Effect of Bisphenol A on Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is considered a predominant chronic liver disease worldwide and a component of metabolic syndrome. Due to its relationship with multiple organs, it is extremely complex to precisely define its pathogenesis as well as to set appropriate therapeutic and preventive strategies. Endocrine disruptors (EDCs) in general, and bisphenol A (BPA) in particular, are a heterogeneous group of substances, largely distributed in daily use items, able to interfere with the normal signaling of several hormones that seem to be related to type 2 diabetes mellitus (T2DM), obesity, and other metabolic disorders. It is reasonable to hypothesize a BPA involvement in the pathogenesis and evolution of NAFLD. However, its mechanisms of action as well as its burden in the vicious circle that connects obesity, T2DM, metabolic syndrome, and NAFLD still remain to be completely defined. In this review we analyzed the scientific evidence on this promising research area, in order to provide an overview of the harmful effects linked to the exposure to EDCs as well as to frame the role that BPA would have in all phases of NAFLD evolution.

Elevated urinary bisphenol A levels are associated with non-alcoholic fatty liver disease among adults in the United States

BACKGROUND AND AIMS

The relationship between bisphenol A (BPA) and non-alcoholic fatty liver disease (NAFLD) is undefined. We studied the impact of BPA on NAFLD.

METHODS

We performed a cross-sectional analysis of data from the National Health and Nutrition Examination Survey (NHANES) 2005-2014 among adults in the United States (US). NAFLD was diagnosed using the hepatic steatosis index (HSI) and the US fatty liver index (USFLI) in the absence of other causes of chronic liver diseases. The first sample using HSI consisted of 7605 adults. The second sample using USFLI consisted of 3631 participants with availability of fasting data.

RESULTS

Of the first 7605 participants (mean age 47 years, 48.4% male), the prevalence of NAFLD and abnormally elevated alanine aminotransferase (ALT) levels was correlated with urinary BPA levels (P < 0.05). Compared to the reference group with lowest quartile of urinary BPA levels, those with the third and fourth quartiles were 81% and 53% more likely to develop NAFLD defined by HSI. In a multivariate model, the ORs for NAFLD in the third and fourth quartiles were 1.69 (95% CI 1.39-2.04) and 1.44 (95% CI 1.19-1.76) respectively (P for trend <0.001). In the second sample using USFLI, high BPA levels (fourth quartile) remained an independent predictor of NAFLD (OR 1.44, 95% CI 1.05-1.98, P for trend = 0.012).

CONCLUSIONS

High levels of urinary BPA were associated with NAFLD in a nationally representative sample of adults in the US. The pathophysiology remains unclear and warrants further investigation.

Long-term bisphenol S exposure induces fat accumulation in liver of adult male zebrafish (Danio rerio) and slows yolk lipid consumption in F1 offspring

Bisphenol S (BPS), as a substitute for bisphenol A, was frequently detected in human urine and blood. It has been reported that BPS could disrupt fat metabolism in vivo and vitro although mechanisms remain unclear. Additionally, there is no study that the disruptive effect of BPS on parental fat metabolism indirectly interferes with the lipid metabolism of offspring. Here, after 120-d exposure to 1, 10, 100, and 1000 μg/L BPS, the transcription level of genes involved in lipid metabolism in liver and feeding regulation of brain-gut axis, as well as the hepatic triacylglycerol (TAG) and plasma lipid levels were investigated in both male and female zebrafish. Results showed that in male liver, fatty acid synthesis and degradation were inhibited by reducing transcription levels of srebp1 and pparα, and the synthesis of TAG was significantly increased using fatty acid as a precursor by elevating agpat4 and dgat2 mRNA expression levels. As a consequence, fat accumulation and the increased TAG levels were observed in male liver, and lipid levels were also elevated in male plasma. In female liver, there was no excessive fat accumulation and BPS exposure had a non-monotonic effect on the gene expression of fasn, dagt2, and pparα. Notably, the unexposed offspring showed a large amount of yolk lipid remain at 5 days post fertilization. This study obviously demonstrated that long-term BPS exposure increases the risk of non-alcoholic fatty liver disease in male zebrafish and life-cycle exposure hazard on offspring is noteworthy.

Ameliorative effect of Silybin on bisphenol A induced oxidative stress, cell proliferation and steroid hormones oxidation in HepG2 cell cultures

Bisphenol A (BPA) and silybin are considered xenoestrogens and could interfere with the action of endogenous hormones. It was demonstrated a higher level of BPA in plasma of nonalcoholic steatohepatitis (NASH) patients, compared to those with steatosis (NAFL). We investigated the effect of BPA and silybin, alone or in combination, on proliferation, oxidative stress and steroid metabolism in HepG2 grown in high glucose concentration medium (H-HepG2). Cell viability was assessed by adding 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). TBARS were quantified by spectrophotometry. The effect of BPA, silybin and their combination on the expression of phosphorilized extracellular signal-regulated kinase (ERK), ERK and Caspase 3 was determined by Western blot analysis. The identifications of lipids and steroid hormones was performed by mass spectrometry. BPA elicited in H-HepG2 oxidative stress and steroid hormones oxidation leading to the formation of metabolite with estrogenic and genotoxic potentials. Silybin ameliorates the harmful BPA-induced effect decreasing glucose uptake and lipid peroxidation. Moreover silybin activates the synthesis of vitamin D3 metabolites and prevent the steroid hormones oxidation. BPA could be considered as an important risk factor in worsening and progression of NAFLD. At the same time silybin could be a valid support to counteract these effects in NASH patients.

Prenatal Bisphenol A Exposure in Mice Induces Multitissue Multiomics Disruptions Linking to Cardiometabolic Disorders

The health impacts of endocrine-disrupting chemicals (EDCs) remain debated, and their tissue and molecular targets are poorly understood. In this study, we leveraged systems biology approaches to assess the target tissues, molecular pathways, and gene regulatory networks associated with prenatal exposure to the model EDC bisphenol A (BPA). Prenatal BPA exposure at 5 mg/kg/d, a dose below most reported no-observed-adverse-effect levels, led to tens to thousands of transcriptomic and methylomic alterations in the adipose, hypothalamus, and liver tissues in male offspring in mice, with cross-tissue perturbations in lipid metabolism as well as tissue-specific alterations in histone subunits, glucose metabolism, and extracellular matrix. Network modeling prioritized main molecular targets of BPA, including Pparg, Hnf4a, Esr1, Srebf1, and Fasn as well as numerous less studied targets such as Cyp51 and long noncoding RNAs across tissues, Fa2h in hypothalamus, and Nfya in adipose tissue. Lastly, integrative analyses identified the association of BPA molecular signatures with cardiometabolic phenotypes in mouse and human. Our multitissue, multiomics investigation provides strong evidence that BPA perturbs diverse molecular networks in central and peripheral tissues and offers insights into the molecular targets that link BPA to human cardiometabolic disorders.

A novel experimental approach for liver analysis in rats exposed to Bisphenol A by means of LC-mass spectrometry and infrared spectroscopy

An innovative complementary approach using a liquid chromatographic-mass spectrometer method and infrared spectroscopy is proposed for measuring internal biological exposure to dangerous chemical contaminants and for monitoring biochemical changes in target organs. The proposed methodologies were validated and applied in the case of rats exposed to low-doses of Bisphenol A (BPA). A liquid chromatographic method coupled to a tandem mass spectrometer was used in order to measure BPA concentration in rat livers. BPA was detected at different levels in all liver samples from BPA-treated rats, although the exposure dose was the same in all treated animals, and also from control rats, highlighting the difficulties in eliminating external uncontrolled exposure and the need for internal biological monitoring. Fourier Transform Infrared analysis was applied to detect structural changes occurring in several molecules (lipids, proteins, carbohydrates and nucleic acids) as well as the presence of specific metabolic processes. The spectroscopic analyses clearly demonstrated a different lipid composition more than an evident lipid accumulation and a glycogen accumulation decrease, revealing a metabolic disturbance in livers with a normal histological aspect. These results demonstrated the potential of an integrated approach based on mass spectrometry and infrared spectroscopy to evaluate at an early stage the hepatotoxic effect of BPA exposure in an animal model. This approach can be usefully exploited in all the investigations aimed to provide better information concerning the interrelationships between contaminant exposure, dose, and health effects.

Experimental BPA Exposure and Glucose-Stimulated Insulin Response in Adult Men and Women

Context

Human cross-sectional and animal studies have shown an association of the chemical bisphenol A (BPA) with insulin resistance, type 2 diabetes, and other metabolic diseases, but no human experimental study has investigated whether BPA alters insulin/C-peptide secretion.

Design

Men and postmenopausal women (without diabetes) were orally administered either the vehicle or a BPA dose of 50 µg/kg body weight, which has been predicted by US regulators (Food and Drug Administration, Environmental Protection Agency) to be the maximum, safe daily oral BPA dose over the lifetime. Insulin response was assessed in two cross-over experiments using an oral glucose tolerance test (OGTT; experiment 1) and a hyperglycemic (HG) clamp (experiment 2). Main outcomes were the percentage change of BPA session measures relative to those of the control session.

Results

Serum bioactive BPA after experimental exposure was at levels detected in human biomonitoring studies. In the OGTT, a strong positive correlation was found between hemoglobin A1c(HbA1c) and the percentage change in the insulinogenic index (Spearman = 0.92), an indicator of early-phase insulin response, and the equivalent C-peptide index (Pearson = 0.97). In the HG clamp study, focusing on the later-phase insulin response to a stable level of glucose, several measures of insulin and C-peptide appeared suppressed during the BPA session relative to the control session; the change in insulin maximum concentration (Cmax) was negatively correlated with HbA1c and the Cmax of bioactive serum BPA.

Conclusions

This exploratory study suggests that BPA exposure to a dose considered safe by US regulators may alter glucose-stimulated insulin response in humans.