Bisphenol A Causes Liver Damage and Selectively Alters the Neurochemical Coding of Intrahepatic Parasympathetic Nerves in Juvenile Porcine Models under Physiological Conditions

The probiotic SLAB51 as agent to counteract BPA toxicity on zebrafish gut microbiota -liver-brain axis

A plethora of studies have so far described the toxic effects of bisphenol A (BPA) on organism health, highlighting the urgent need to find new strategies not only to reduce the presence of this toxicant but also to counteract its adverse effects. In this context, probiotics emerged as a potential tool since they promote organism welfare. Using a multidisciplinary approach, this study explores the effects of SLAB51 dietary administration to counteract BPA toxicity using zebrafish as a model. Adult males and females were maintained under standard conditions (control group; C), exposed for 28 days via the water to an environmental relevant dose of BPA (10 μg/L; BPA), dietary treated with SLAB51 (109 CFU/g of body weight; P) and co-treated with BPA plus SLAB51 (BPA + P). In the gut, exposure to BPA resulted in altered architecture in both males and females, with females also experiencing an increase of pathogenic bacterial species. Co-administration of BPA + P led to the restoration of normal gut architecture, favored beneficial bacteria colonization, and decreased the abundance of pathogenic species. In the liver, male BPA exposure led to steatosis and glycogen depletion, which was partially mitigated by SLAB51 co-administration. In contrast, in females exposed to BPA, the lack of steatosis along with the greater glycogen depletion, suggested an increase in energy demand as supported by the metabolomic phenotype. The analysis of liver metabolites in BPA + P males revealed increased levels of anserine and reduced levels of glutamine, which could lie behind the counteraction of the brain histopathological damage caused by BPA. In BPA + P females, a reduction of retinoic acid was found in the liver, suggesting an increase in retinoids responsible for BPA detoxification. Overall, these results demonstrate that SLAB51 exerts its beneficial effects on the gut microbiota-brain-liver axis through distinct molecular pathways, effectively mitigating the pleiotropic toxicity of BPA.

Environment, Endocrine Disruptors, and Fatty Liver Disease Associated with Metabolic Dysfunction (MASLD)

Ecological theories suggest that environmental factors significantly influence obesity risk and related syndemic morbidities, including metabolically abnormal obesity associated with nonalcoholic fatty liver disease (MASLD). These factors encompass anthropogenic influences and endocrine-disrupting chemicals (EDCs), synergistically interacting to induce metabolic discrepancies, notably in early life, and disrupt metabolic processes in adulthood. This review focuses on endocrine disruptors affecting a child's MASLD risk, independent of their role as obesogens and thus regardless of their impact on adipogenesis. The liver plays a pivotal role in metabolic and detoxification processes, where various lipophilic endocrine-disrupting molecules accumulate in fatty liver parenchyma, exacerbating inflammation and functioning as new anthropogenics that perpetuate chronic low-grade inflammation, especially insulin resistance, crucial in the pathogenesis of MASLD.

Exposure to low dose of Bisphenol A (BPA) intensifies kidney oxidative stress, inflammatory factors expression and modulates Angiotensin II signaling under hypertensive milieu

Humans are constantly exposed to low concentrations of ubiquitous environmental pollutant, Bisphenol A (BPA). Due to the prevalence of hypertension (one of the major risk factors of cardiovascular disease [CVD]) in the population, it is necessary to explore the adverse effect of BPA under hypertension associated pathogenic milieu. The current study exposed the Nω-nitro-l-arginine methyl ester (L-NAME) induced hypertensive Wistar rats to low dose BPA (50 μg/kg) for 30 days period. In tissue samples immunohistochemistry, real-time quantitative polymerase chain reaction and enzymatic assays were conducted. Moreover, studies on primary kidney cell culture were employed to explore the impact of low dose of BPA exposure at nanomolar level (20-80 nM range) on renal cells through various fluorescence assays. The observed results illustrate that BPA exposure potentiates/aggravates hypertension induced tissue abnormalities (renal fibrosis), oxidative stress (ROS generation), elevated angiotensin-converting enzyme activity, malfunction of the antioxidant and tricarboxylic acid cycle enzymes, tissue lipid abnormalities and inflammatory factor expression (both messenger RNA and protein level of TNF-α and IL-6). Further, in vitro exposure of nM levels of BPA to primary kidney cells modulates oxidative stress (both superoxide and total ROS), mitochondrial physiology (reduced mitochondrial transmembrane potential-∆ψm) and lipid peroxidation in a dose dependent manner. In addition, angiotensin II induced ROS generation was aggravated further by BPA during coexposure in kidney cells. Therefore, during risk assessment, a precise investigation on BPA exposure in hypertensive (CVD vulnerable) populations is highly suggested.

Bisphenol A (BPA) exposure aggravates hepatic oxidative stress and inflammatory response under hypertensive milieu - Impact of low dose on hepatocytes and influence of MAPK and ER stress pathways

Human exposure to the hazardous chemical, Bisphenol A (BPA), is almost ubiquitous. Due to the prevalence of hypertension (CVD risk factor) in the aged human population, it is necessary to explore its adverse effect in hypertensive subjects. The current study exposed the Nω-nitro-l-arginine methyl ester (L-NAME) induced hypertensive Wistar rats to human exposure relevant low dose of BPA (50 μg/kg) for 30 days period. The liver biochemical parameters, histopathology, immunohistochemistry, gene expression (RT-qPCR), trace elements (ICP-MS), primary rat hepatocytes cell culture and metabolomic (1H NMR) assessments were performed. Results illustrate that BPA exposure potentiates/aggravates hypertension induced tissue abnormalities (hepatic fibrosis), oxidative stress, ACE activity, malfunction of the antioxidant system, lipid abnormalities and inflammatory factor (TNF-α and IL-6) expression. Also, in cells, BPA increased ROS generation, mitochondrial dysfunction and lipid peroxidation without any impact on cytotoxicity and caspase 3 and 9 activation. Notably, BPA exposure modulate lipid metabolism (cholesterol and fatty acid) in primary hepatocytes. Finally, the influence of ERK1/2, p38MAPK, ER stress and oxidative stress during relatively high dose of BPA elicited cytotoxicity was observed. Therefore, a precise hazardous risk investigation of BPA exposure in hypertensive populations is highly recommended.

Does bisphenol A (BPA) participates in the pathogenesis of Polycystic Ovary Syndrome (PCOS)?

PCOS is an endocrine disorder characterized by chronic anovulation, hyperandrogenism, and polycystic ovaries. Its etiology is uncertain. It is debated whether BPA would be a component of the environmental factor in the etiology of PCOS. Contamination by BPA can occur from food packaging (exposure during the diet) and through skin absorption and/or inhalation. It can be transferred to the fetus via the placenta or to the infant via breast milk, and it can be found in follicular fluid, fetal serum, and amniotic fluid. The phenolic structure of BPA allows it to interact with Estrogen Receptors (ERs) through genomic signaling, in which BPA binds to nuclear ERα or Erβ, or through nongenomic signaling by binding to membrane ERs, prompting a rapid and intense response. With daily and constant exposure, BPA's tendency to bioaccumulate and its ability to activate nongenomic signaling pathways can alter women's metabolic and reproductive function, leading to hyperandrogenism, insulin resistance, obesity, atherogenic dyslipidemia, chronic inflammatory state, and anovulation and favoring PCOS. The harmful changes caused by BPA can be passed on to future generations without the need for additional exposure because of epigenetic modifications. Not only high BPA levels can produce harmful effects, but at low levels, BPA may be harmful when exposure occurs during the most vulnerable periods, such as the fetal and neonatal periods, as well as during the prepubertal age causing an early accumulation of BPA in the body. Learning how BPA participates in the pathogenesis of PCOS poses a challenge and further studies should be conducted.

Alterations induced by Bisphenol A on cellular organelles and potential relevance on human health

Bisphenol A (BPA) is a chemical partially soluble in water and exists in a solid state. Its structural similarity with estrogen makes it an endocrine-disrupting chemical. BPA can disrupt signaling pathways at very low doses and may cause organellar stress. According to in vitro and in vivo studies, BPA interacts with various cell surface receptors to cause organellar stress, producing free radicals, cellular toxicity, structural changes, DNA damage, mitochondrial dysfunction, cytoskeleton remodeling, centriole duplication, and aberrant changes in several cell signaling pathways. The current review summarizes the impact of BPA exposure on the structural and functional aspects of subcellular components of cells such as the nucleus, mitochondria, endoplasmic reticulum, lysosome, ribosome, Golgi apparatus, and microtubules and its consequent impact on human health.

Bisphenol A is a carcinogen that induces lipid accumulation, peroxisome proliferator‑activated receptor‑γ expression and liver disease

Bisphenol (BP) A is an exogenous endocrine disruptor that mimics hormones closely associated with health complications, e.g., obesity and cancers. The present study aimed to evaluate the effects of BPA on human liver cells and tissue. The peroxisome proliferator-activated receptor (PPAR)-γ expression profile across tumour samples and paired normal tissue was first analysed using GEPIA. Subsequently, BPA-treated liver THLE-2 cell viability was evaluated using an MTT assay. Clusterin, PPARα and PPARγ gene expression in BPA-treated THLE-2 cells was assessed using GEPIA before validating the gene expression using real-time PCR and analysing overall survival using TCGA data in GEPIA. Cytoplasmic lipid accumulation was examined in BPA-treated THLE-2 cells using Oil Red O staining, and liver tissue was examined using haematoxylin and eosin staining. Finally, cytochrome P450 (CYP) gene expression was assessed in BPA-treated THLE-2 cells using real-time PCR. PPARγ is likely the primary nuclear receptor protein involved in lipid accumulation in THLE-2 cells following BPA treatment and is associated with liver disease. THLE-2 cells exposed to BPA showed a decrease in viability and lipid accumulation after 48 h treatment. Higher PPARγ gene expression was significantly associated with survival of patients with liver cancer, with an average survival time of <80 months. Haematoxylin and eosin-stained sections showed notable disruption of the liver architecture in tissue exposed to BPA. Downregulated CYP1A1 and CYP1B1 gene expression implied that BPA-treated THLE-2 cells decreased capacity for carcinogen metabolism, while upregulated CYP2S1 gene expression exerted minimal cytotoxicity. The present study revealed that BPA served as a carcinogen, enhanced tumorigenesis susceptibility and may induce other types of liver disease.

Nattokinase attenuates bisphenol A or gamma irradiation-mediated hepatic and neural toxicity by activation of Nrf2 and suppression of inflammatory mediators in rats

Nattokinase (NK), a protease enzyme produced by Bacillus subtilis, has various biological effects such as lipid-lowering activity, antihypertensive, antiplatelet/anticoagulant, and neuroprotective effects. Exposure to environmental toxicants such as bisphenol A (BPA) or γ-radiation (IR) causes multi-organ toxicity through several mechanisms such as impairment of oxidative status, signaling pathways, and hepatic and neuronal functions as well as disruption of the inflammatory responses. Therefore, this study is designed to evaluate the ameliorative effect of NK against BPA- or IR-induced liver and brain damage in rats. Serum ammonia level and liver function tests were measured in addition to brain oxidative stress markers, amyloid-beta, tau protein, and neuroinflammatory mediators. Moreover, relative quantification of brain nuclear factor-erythroid 2-related factor-2 (Nrf2)/heme oxygenase-1 (HO-1) genes, as well as apoptotic markers in brain tissue, was carried out in addition to histopathological examination. The results showed that NK improved liver functions, impaired oxidative status, the cholinergic deficits, and minified the misfolded proteins aggregates. Furthermore, NK alleviated the neuroinflammation via modulating NF-κB/Nrf2/HO-1 pathway and glial cell activation in addition to their antiapoptotic effect. Collectively, the current results revealed the protective effect of NK against hepatic and neurotoxicity derived from BPA or IR.

Starch-Based Hydrogel Nanoparticles Loaded with Polyphenolic Compounds of Moringa Oleifera Leaf Extract Have Hepatoprotective Activity in Bisphenol A-Induced Animal Models

Bisphenol A (BPA) is an xenoestrogenic chemical used extensively in the fabrication of baby bottles, reusable plastic water bottles and polycarbonate plastic containers. The current study aims to investigate the hepatoprotective activity of Moringa oleifera Lam leaf extract (MOLE) and hydrogel NPs made of starch-MOLE-Bovine Serum Albumin (BSA) against Bisphenol A-induced liver toxicity in male rats. Fabrication and characterization of hydrogel NPs formed of starch-MOLE-BSA were investigated using FTIR, TEM, zeta potential, UV-visible spectroscopy and fluorescence spectrophotometer. The potential efficacy of hydrogel NPs was studied. Compared to the results of control, the level of liver function, oxidative stress markers and lipid profile status were remodulated in the groups treated with MOLE and hydrogel NPs (Encap. MOLE). Meanwhile, the administration of MOLE and Encap MOLE significantly increased antioxidant activity and decreased the level of apoptotic pathways. Heme oxygenase (HO)-1 and growth arrest -DNA damage-inducible gene 45b (Gadd45b) were also regulated in the groups treated with MOLE and Encap. MOLE compared to the group which received BPA alone. In the present study, MOLE and hydrogel NPs led to remarkable alterations in histological changes during BPA administration. Overall, MOLE has a potential antioxidant activity which can be used in the treatment of liver disorders.

Prenatal Bisphenol a Exposure and Postnatal Trans Fat Diet Alter Small Intestinal Morphology and Its Global DNA Methylation in Male Sprague-Dawley Rats, Leading to Obesity Development

In this study, we aimed to determine whether a postnatal trans fat diet (TFD) could aggravate prenatal bisphenol A (BPA) exposure effects on offspring’s small intestine and adulthood obesity, due to the relatively sparse findings on how the interaction between these two variables interrupt the small intestinal cells. Twelve pregnant rats were administered with either unspiked drinking water (control; CTL) or BPA-spiked drinking water throughout pregnancy. Twelve weaned pups from each pregnancy group were then given either a normal diet (ND) or TFD from postnatal week (PNW) 3 until PNW14, divided into control offspring on normal diet (CTL-ND), BPA-exposed offspring on normal diet (BPA-ND), control offspring on trans fat diet (CTL-TFD), and BPA offspring on trans fat diet (BPA-TFD) groups. Body weight (BW), waist circumference, and food and water intake were measured weekly in offspring. At PNW14, small intestines were collected for global DNA methylation and histological analyses. Marked differences in BW were observed starting at PNW9 in BPA-TFD (389.5 ± 10.0 g; p < 0.05) relative to CTL-ND (339.0 ± 7.2 g), which persisted until PNW13 (505.0 ± 15.6 g). In contrast, water and food intake between offspring were significantly different (p < 0.01−0.05) at earlier ages only (PNW4−6 and PNW7−9, respectively). Furthermore, substantial differences in the general parameters of the intestinal structures were exclusive to ileum crypt length alone, whereby both BPA-ND (150.5 ± 5.1 μm; p < 0.001), and BPA-TFD (130.3 ± 9.9 μm; p < 0.05) were significantly longer than CTL-ND (96.8 ± 8.9 μm). Moreover, BPA-ND (2.898 ± 0.147%; p < 0.05) demonstrated global small intestinal hypermethylation when compared to CTL-ND and CTL-TFD (1.973 ± 0.232% and 1.913 ± 0.256%, respectively). Prenatal BPA exposure may significantly affect offspring’s physiological parameters and intestinal function. Additionally, our data suggest that there might be compensatory responses to postnatal TFD in the combined BPA prenatal group (BPA-TFD).

Non-targeted metabolomics revealing the effects of bisphenol analogues on human liver cancer cells

Bisphenol analogues (BPs) are widely used in plastics, food packaging and other commercial products as non safer alternative of BPA. As emerging environmental contaminants, BPs have received considerable attention for their adverse effects on human health. However, their effects on liver metabolisms are only marginally understood. In this study, high-resolution mass spectrometry-based global metabolomics and extracellular flux (XF) analysis were applied to characterize the cellular metabolome alterations and reveal the possible mechanisms of the metabolic disorders associated with BPs-induced toxicity in HepG2 cells. BPE, BPB and BPAP with similar chemical structures were selected to compare their interference with different metabolic pathways. A total of 61 key metabolite profiles were significantly altered after exposure to the three BPs. Overall, BPs altered metabolites which are associated with energy metabolism, oxidative stress, cell proliferation and nucleotides synthesis. The primary dysregulated pathways included energy and nucleotides synthesis related Purine and Glycolysis/Gluconeogenesis metabolism. In addition, attenuated mitochondrial function and enhanced glycolysis were found under BPB and BPAP treatment. While attenuated glycolysis was observed under BPE treatment. These findings may provide potential biomarkers indicating the cytotoxicity of BPs and prompt a deeper understanding of the intramolecular metabolic processes induced by BPs exposure.

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

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

Autism-Related Transcription Factors Underlying the Sex-Specific Effects of Prenatal Bisphenol A Exposure on Transcriptome-Interactome Profiles in the Offspring Prefrontal Cortex

Bisphenol A (BPA) is an environmental risk factor for autism spectrum disorder (ASD). BPA exposure dysregulates ASD-related genes in the hippocampus and neurological functions of offspring. However, whether prenatal BPA exposure has an impact on genes in the prefrontal cortex, another brain region highly implicated in ASD, and through what mechanisms have not been investigated. Here, we demonstrated that prenatal BPA exposure disrupts the transcriptome-interactome profiles of the prefrontal cortex of neonatal rats. Interestingly, the list of BPA-responsive genes was significantly enriched with known ASD candidate genes, as well as genes that were dysregulated in the postmortem brain tissues of ASD cases from multiple independent studies. Moreover, several differentially expressed genes in the offspring's prefrontal cortex were the targets of ASD-related transcription factors, including AR, ESR1, and RORA. The hypergeometric distribution analysis revealed that BPA may regulate the expression of such genes through these transcription factors in a sex-dependent manner. The molecular docking analysis of BPA and ASD-related transcription factors revealed novel potential targets of BPA, including RORA, SOX5, TCF4, and YY1. Our findings indicated that prenatal BPA exposure disrupts ASD-related genes in the offspring's prefrontal cortex and may increase the risk of ASD through sex-dependent molecular mechanisms, which should be investigated further.

Potential role of green tea extract and epigallocatechin gallate in preventing bisphenol A-induced metabolic disorders in rats: Biochemical and molecular evidence

BACKGROUND

Bisphenol A (BPA) is an artificial chemical widely used in the production of polycarbonate plastics and epoxy resins. Accumulating evidence indicates that BPA exposure is associated with metabolic disorders. The beneficial effects of green tea and epigallocatechin gallate (EGCG), major catechin present in green tea, on alleviating BPA-induced metabolic disorders have been shown in various studies.

PURPOSE

Protective effects of green tea extract and EGCG on BPA-induced metabolic disorders and possible underlying mechanisms were investigated.

METHODS

Rats were randomly divided into control, green tea extract (50 and 100 mg/kg, IP), EGCG (20 and 40 mg/kg, IP), BPA (10 mg/kg, gavage), BPA plus green tea extract (25, 50, and 100 mg/kg, IP), BPA plus EGCG (10, 20, and 40 mg/kg, IP), and BPA plus vitamin E (200 IU/kg, IP). After two months, body weight, blood pressure, biochemical blood tests, hepatic malondialdehyde (MDA), and glutathione (GSH) were assessed. By enzyme-linked immunosorbent assay, serum levels of insulin, leptin, adiponectin, TNFα, and IL-6, and by western blotting, hepatic insulin signaling (IRS-1, PI3K, Akt) were measured.

RESULTS

BPA increased body weight, blood pressure, and MDA, decreased GSH, elevated serum levels of low-density lipoprotein cholesterol, total cholesterol, triglyceride, glucose, insulin, leptin, TNFα, IL-6, and liver enzymes including alanine aminotransferase and alkaline phosphatase, and lowered high-density lipoprotein cholesterol and adiponectin levels. In western blot, decreased phosphorylation of IRS-1, PI3K, and Akt was obtained. Administration of green tea extract, EGCG, or vitamin E with BPA reduced the detrimental effects of BPA.

CONCLUSION

These findings indicate that green tea extract and EGCG can be effective in preventing or reducing metabolic disorders induced by BPA linked to their antioxidant and anti-inflammatory activity, regulating the metabolism of lipids, and improving insulin signaling pathways.

Effects of Bisphenol A and Bisphenol S Exposure at Low Doses on the Metabolome of Adolescent Male Sprague-Dawley Rats

Toxic effects induced upon exposure to low-dose bisphenol A (BPA) or bisphenol S (BPS) remains controversial. In this study, metabolomics was used to examine the metabolomic perturbation arising from 28 days of exposure to BPA or BPS at 50 μg/kg bw/day in Sprague-Dawley (SD) rats. Endogenous metabolite profiling revealed a clear discrimination of metabolome in the rat plasma among BPA-treatment, BPS-treatment, and control groups. BPA exposure induced the up-regulation of 19 metabolites and down-regulation of 32 metabolites in plasma of SD rats, compared with the control. BPS exposure induced the up-regulation of 15 metabolites and the down-regulation of 33 metabolites in the plasma of SD rats, compared with the control. Joint pathway analysis suggested marked perturbations in the citrate cycle, butanoate metabolism, and alanine, aspartate, and glutamate metabolism for BPA-exposed rats as well as glycerophospholipid metabolism for BPS-exposed rats. These findings provide novel insights into associations between the metabolomic perturbation and phenotypic changes arising from BPA and BPS exposure.

Increased PACAP- and DβH-Positive Hepatic Nerve Fibers after Bisphenol A Exposure

Bisphenol A (BPA) is an endocrine-disrupting compound (EDC) that can be found nearly everywhere in our polluted world. BPA has been correlated with pathophysiologies that include psychological disorders, especially in children. This study used juvenile porcine models to investigate the effects of BPA on the liver of developing vertebrates in order to determine the effects of BPA on innervated hepatic samples with the use of double-labeled immunofluorescence. This study specifically investigated the sympathetic nervous system (SNS) colocalized with a specific neural marker (PACAP) that has previously been correlated with specific pathophysiologies in the literature. In the liver, it was observed that there were significantly increased nerve fibers in the SNS colocalized with the neural marker PACAP after exposure to BPA at concentrations considered to be “safe” with the same or more profound effects at higher exposure levels. The implications of childhood exposure to BPA are then discussed with regard to several correlation studies that have linked BPA exposure to behavioral/psychological disorders. It is possible that BPA exposure in childhood may upregulate the SNS and PACAP levels, thereby contributing to the correlations in the literature.

A comprehensive review on the carcinogenic potential of bisphenol A: clues and evidence

Bisphenol A [BPA; (CH₃)₂C(C₆H₄OH)₂] is a synthetic chemical used as a precursor material for the manufacturing of plastics and resins. It gained attention due to its high chances of human exposure and predisposing individuals at extremely low doses to diseases, including cancer. It enters the human body via oral, inhaled, and dermal routes as leach-out products. BPA may be anticipated as a probable human carcinogen. Studies using in vitro cell lines, rodent models, and epidemiological analysis have convincingly shown the increasing susceptibility to cancer at doses below the oral reference dose set by the Environmental Protection Agency for BPA. Furthermore, BPA exerts its toxicological effects at the genetic and epigenetic levels, influencing various cell signaling pathways. The present review summarizes the available data on BPA and its potential impact on cancer and its clinical outcome.

Changes Caused by Low Doses of Bisphenol A (BPA) in the Neuro-Chemistry of Nerves Located in the Porcine Heart

Simple Summary

Bisphenol A (BPA) is a substance commonly used in the plastics industry, which is a part of many everyday items. It may leach from plastics and penetrate food, water, soil and air. It is known that BPA negatively affects living organisms. It impairs the functions of the intestine, neurons, reproductive organs, endocrine glands and immune cells. Previous studies have also reported that BPA negatively influences the cardiovascular system, leading to heart arrhythmia, intensification of atherosclerosis, blood hypertension and increased risk of a heart attack. However, many aspects of the influence of BPA on the heart are still poorly understood. One of these aspects is the BPA impact on heart innervation. Therefore, this article aimed to investigate the influence of low doses of BPA on the number of nerves containing selected active substances taking part in neuronal stimuli conduction located in the porcine heart apex. The results indicate that even relatively low doses of BPA are not neutral to the cardiovascular system, because they affect the neurochemical characterization of nerves in the heart. These changes may underlie the negative effects of BPA on the heart.

Abstract

Bisphenol A (BPA) contained in plastics used in the production of various everyday objects may leach from these items and contaminate food, water and air. As an endocrine disruptor, BPA negatively affects many internal organs and systems. Exposure to BPA also contributes to heart and cardiovascular system dysfunction, but many aspects connected with this activity remain unknown. Therefore, this study aimed to investigate the impact of BPA in a dose of 0.05 mg/kg body weight/day (in many countries such a dose is regarded as a tolerable daily intake–TDI dose of BPA–completely safe for living organisms) on the neurochemical characterization of nerves located in the heart wall using the immunofluorescence technique. The obtained results indicate that BPA (even in such a relatively low dose) increases the number of nerves immunoreactive to neuropeptide Y, substance P and tyrosine hydroxylase (used here as a marker of sympathetic innervation). However, BPA did not change the number of nerves immunoreactive to vesicular acetylcholine transporter (used here as a marker of cholinergic structures). These observations suggest that changes in the heart innervation may be at the root of BPA-induced circulatory disturbances, as well as arrhythmogenic and/or proinflammatory effects of this endocrine disruptor. Moreover, changes in the neurochemical characterization of nerves in the heart wall may be the first sign of exposure to BPA.

Bisphenol A and Type 2 Diabetes Mellitus: A Review of Epidemiologic, Functional, and Early Life Factors

Type 2 diabetes mellitus (T2DM) is characterised by insulin resistance and eventual pancreatic β-cell dysfunction, resulting in persistent high blood glucose levels. Endocrine disrupting chemicals (EDCs) such as bisphenol A (BPA) are currently under scrutiny as they are implicated in the development of metabolic diseases, including T2DM. BPA is a pervasive EDC, being the main constituent of polycarbonate plastics. It can enter the human body by ingestion, through the skin, and cross from mother to offspring via the placenta or breast milk. BPA is a xenoestrogen that alters various aspects of beta cell metabolism via the modulation of oestrogen receptor signalling. In vivo and in vitro models reveal that varying concentrations of BPA disrupt glucose homeostasis and pancreatic β-cell function by altering gene expression and mitochondrial morphology. BPA also plays a role in the development of insulin resistance and has been linked to long-term adverse metabolic effects following foetal and perinatal exposure. Several epidemiological studies reveal a significant association between BPA and the development of insulin resistance and impaired glucose homeostasis, although conflicting findings driven by multiple confounding factors have been reported. In this review, the main findings of epidemiological and functional studies are summarised and compared, and their respective strengths and limitations are discussed. Further research is essential for understanding the exact mechanism of BPA action in various tissues and the extent of its effects on humans at environmentally relevant doses.

Changes in the Population Size of Calbindin D-28k-Immunoreactive Enteric Neurons in the Porcine Caecum under the Influence of Bisphenol A: A Preliminary Study

Calbindin D-28k (CB) is a calcium-binding protein widely distributed in living organisms that may act as a calcium buffer and sensory protein. CB is present in the enteric nervous system (ENS) situated in the gastrointestinal tract, which controls the majority of activities of the stomach and intestine. The influence of various doses of bisphenol A (BPA)—a chemical compound widely used in plastics production—on the number and distribution of CB-positive enteric neuronal cells in the porcine caecum was investigated with an immunofluorescence technique. The obtained results showed that low dosages of BPA resulted in an increase in the number of CB-positive neuronal cells in the myenteric (MP) and inner submucous (ISP) plexuses, whereas it did not alter the number of such neuronal cells in the outer submucous plexus (OSP). High dosages of BPA caused the increase in the amount of CB-positive perikarya in all the above-mentioned kinds of the caecal neuronal plexuses. These observations strongly suggest that CB in the ENS participates in the processes connected with the toxic activity of BPA. Most likely, the changes noted in this experiment result from the adaptive and protective properties of CB.

Bisphenol A (BPA) Affects the Enteric Nervous System in the Porcine Stomach

Bisphenol A (BPA) is widely utilized in plastic production process all over the world. Previous studies have shown that BPA, with its similarity to estrogen, may negatively affect living organisms. It is acknowledged that BPA distorts the activity of multiple internal systems, including the nervous, reproductive, urinary, and endocrine systems. BPA also affects the gastrointestinal tract and enteric nervous system (ENS), which is placed throughout the wall from the esophagus to the rectum. Contrary to the intestine, the influence of BPA on the ENS in the stomach is still little known. This study, performed using the double immunofluorescence method, has revealed that BPA affects the number of nervous structures in the porcine gastric wall immunoreactive to vesicular acetylcholine transporter (VAChT, a marker of cholinergic neurons), substance P (SP), vasoactive intestinal polypeptide (VIP), galanin (GAL) and cocaine- and amphetamine-regulated transcript peptide (CART). The character and severity of noted alterations depended on the part of the ENS, the BPA dose, and the type of neuronal substance. Administration of BPA resulted in an increase in the number of nervous structures containing SP, GAL, and/or CART, and a decrease in the number of cholinergic neurons in all parts of the gastric wall. The number of VIP-positive nervous structures increased in the enteric myenteric ganglia, along with the muscular and mucosal layers, whilst it decreased in the submucous ganglia. The exact mechanism of noted changes was not absolutely obvious, but they were probably related to the neuroprotective and adaptive processes constituting the response to the impact of BPA.

Effects of endocrine disrupting chemicals in pigs

Endocrine-disrupting chemicals (EDCs) are compounds that interfere with the expression, synthesis, and activity of hormones in organisms. They are released into the environment from flame retardants and products containing plasticizers. Persistent pesticides, such as dichlorodiphenyltrichloroethane (DDT) and hexachlorobenzene, also disrupt the endocrine system through interaction with hormone receptors. Endogenous hormones, such as 17β-estradiol (E2), are released in the urine and feces of farm animals and seep into terrestrial and aquatic ecosystems through sewage. Pigs are widely used as animal models to determine the effects of EDCs because they are physiologically, biochemically, and histologically similar to humans. EDCs primarily disrupt the reproductive and nervous systems of pigs. Moreover, embryonic development during the prenatal and early postnatal periods is particularly sensitive to EDCs. Mycotoxins, such as zearalenone, are food contaminants that alter hormonal activities in pigs. Mycotoxins also alter the innate immune system in pigs, making them vulnerable to diseases. It has been reported that farm animals are exposed to various types of EDCs, which accumulate in tissues, such as those of gonads, livers, and intestines. There is a lack of an integrated understanding of the impact of EDCs on porcine reproduction and development. Thus, this article aims to provide a comprehensive review of literature regarding the effects of EDCs in pigs.

The Influence of Bisphenol a on the Nitrergic Nervous Structures in the Domestic Porcine Uterus

Bisphenol A (BPA) is one of the most common environmental pollutants among endocrine disruptors. Due to its similarity to estrogen, BPA may affect estrogen receptors and show adverse effects on many internal organs. The reproductive system is particularly vulnerable to the impact of BPA, but knowledge about BPA-induced changes in the innervation of the uterus is relatively scarce. Therefore, this study aimed to investigate the influence of various doses of BPA on nitrergic nerves supplying the uterus with the double immunofluorescence method. It has been shown that even low doses of BPA caused an increase in the number of nitrergic nerves in the uterine wall and changed their neurochemical characterization. During the present study, changes in the number of nitrergic nerves simultaneously immunoreactive to substance P, vasoactive intestinal polypeptide, pituitary adenylate cyclase-activating peptide, and/or cocaine- and amphetamine-regulated transcript were found under the influence of BPA. The obtained results strongly suggest that nitrergic nerves in the uterine wall participate in adaptive and/or protective processes aimed at homeostasis maintenance in the uterine activity under the impact of BPA.

Hepatic Autonomic Nervous System and Neurotrophic Factors Regulate the Pathogenesis and Progression of Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease represents a continuum of excessive hepatic steatosis, inflammation and fibrosis. It is a growing epidemic in the United States of America and worldwide. Progression of non-alcoholic fatty liver disease can lead to morbidity and mortality due to complications such as cirrhosis or hepatocellular carcinoma. Pathogenesis of non-alcoholic fatty liver disease is centered on increased hepatic lipogenesis and decreased hepatic lipolysis in the setting of hepatic and systemic insulin resistance. Adipose tissue and hepatic inflammation can further perpetuate the severity of illness. Currently there are no approved therapies for non-alcoholic fatty liver disease. Most of the drugs being explored for non-alcoholic fatty liver disease focus on classical pathogenic pathways surrounding hepatic lipid accumulation, inflammation or fibrosis. Studies have demonstrated that the autonomic nervous system innervating the liver plays a crucial role in regulation of hepatic lipid homeostasis, inflammation and fibrosis. Additionally, there is growing evidence that neurotrophic factors can modulate all stages of non-alcoholic fatty liver disease. Both the autonomic nervous system and neurotrophic factors are altered in patients and murine models of non-alcoholic fatty liver disease. In this review we focus on the pathophysiological role of the autonomic nervous system and neurotrophic factors that could be potential targets for novel therapeutic approaches to treat non-alcoholic fatty liver disease.

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

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

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.

Metabolomic modulations of HepG2 cells exposed to bisphenol analogues

Bisphenol analogues including bisphenol A (BPA), bisphenol AF (BPAF), bisphenol F (BPF), and bisphenol S (BPS) share similar chemical structures and endocrine disrupting effects. Their effects on metabolisms, however, are so far only marginally understood. In this study, NMR-based metabonomic profiles of HepG2 cell culture media and PCR array were used to assess the metabolomics disturbances and gene expression levels of HepG2 in response to four BPs (BPA, BPAF, BPF, and BPS). The results indicated that BP analogues resulted in disturbances in 7-15 metabolites that were classified as amino acid (alanine, glutamine, glutamate), intermediates and end-products in the glycolysis (pyruvate) and the tricarboxylic acid cycle (acetate, lactate). Their rank in order according to the number of metabolites and pathways was BPF > BPA > BPAF > BPS. The common disrupted pathways (pyruvate metabolism; alanine, aspartate, and glutamate metabolism) indicated enhanced glycolysis. The following glucometabolic PCR array analysis suggested that although four BPs shared the capability of disrupting glucose metabolism, they may act through different mechanisms: BPAF has increased the pyruvate kinase (PKLR) expression level, which implied enhanced glycolysis that was agreed with NMR results. The other three BP analogues, however, decreased the expression level of glucokinase (GCK) that indicated glucose sensing impairment. Our results demonstrated the potential for using metabolomic and PCR array to understand the underlying action of mechanisms and identify the potential targets for future targeted risk assessment.

Neurochemical characterization of the enteric neurons within the porcine jejunum in physiological conditions and under the influence of bisphenol A (BPA)

BACKGROUND

Bisphenol A (BPA) is commonly used in the production of plastics and has multidirectional, negative effects on the living organisms. It may also affect the enteric nervous system (ENS) located in the wall of the gastrointestinal tract. Enteric neurons express many active substances, which regulate majority of intestinal activities not only in physiological conditions but also under the impact of pathological factors.

METHODS

The influence of various doses of BPA on the ENS of jejunum has been investigated using the double immunofluorescence technique. The commercial antibodies against substance P (SP), vasoactive intestinal polypeptide (VIP), galanin (GAL), vesicular acetylcholine transporter (VAChT), and cocaine- and amphetamine-regulated transcript peptide (CART) were used.

KEY RESULTS

Both doses of BPA studied changed the number of the enteric neurons immunoreactive to SP, VIP, GAL, VAChT, and CART, and the intensity of fluctuations depended on the BPA dose and on the type of the enteric plexus. Bisphenol A causes the increase in the number of neurons immunoreactive to the majority of substances studied. The only exception was VAChT-positive neurons, the number of which was lower under the impact of BPA in the comparison with physiological conditions.

CONCLUSIONS & INFERENCES

Even low doses of BPA cause the changes in neurochemical characterization of the enteric neurons in the jejunum. These changes may be the first sign of subclinical BPA intoxication. The mechanisms of observed changes are probably connected with neurotoxic and/or pro-inflammatory activity of BPA, but their exact mechanisms are not fully explained.

The Influence of Bisphenol A (BPA) on Neuregulin 1-Like Immunoreactive Nerve Fibers in the Wall of Porcine Uterus

Bisphenol A (BPA), a substance commonly used in the manufacture of plastics, shows multidirectional negative effects on humans and animals. Due to similarities to estrogens, BPA initially leads to disorders in the reproductive system. On the other hand, it is known that neuregulin 1 (NRG-1) is an active substance which enhances the survivability of cells, inhibits apoptosis, and protects tissues against damaging factors. Because the influence of BPA on the nervous system has also been described, the aim of the present study was to investigate for the first time the influence of various doses of BPA on neuregulin 1-like immunoreactive (NRG-1-LI) nerves located in the porcine uterus using the routine single- and double-immunofluorescence technique. The obtained results have shown that BPA increases the number and affects the neurochemical characterization of NRG-1-LI in the uterus, and changes are visible even under the impact of small doses of this toxin. The character of observed changes depended on the dose of BPA and the part of the uterus studied. These observations suggest that NRG-1 in nerves supplying the uterus may play roles in adaptive and protective mechanisms under the impact of BPA.

The state of bisphenol research in the lesser developed countries of the EU: a mini-review

Bisphenol compounds are a class of chemical epoxy resins that are found throughout the world in food packaging, thermal paper products, dental materials, and more. These compounds were deemed to be safe until recently, when some studies noticed adverse effects at very low doses, due to the fact that bisphenol acts as an endocrine disruptor. Over the last ten years, studies have been performed to detect bisphenols (especially BPA) in serum and blood samples throughout the world. Essentially, the majority of the earth's population seems to have significantly measurable levels of bisphenol in their blood plasma or urine. However, the majority of the population is unaware that a potential danger may exist. The purpose of this mini-review is to report upon the state of bisphenol research in the lesser developed member-states of the European Union and to increase awareness of the exposure level and possible adverse health effects of this endocrine disruptor. The results show that only three of the most newly admitted members of the European Union have published research concerning the health effects and/or environmental exposure of EU citizens to bisphenol compounds. Those countries were Slovenia, Poland and the Czech Republic. The rest of the surveyed member-states had little or no published research in relation to bisphenol compounds. Furthermore, even the three nations referred to above still lagged far behind the more advanced EU member-states. The lack of research could translate into a lack of awareness amongst the citizenry of nearly half of the EU, and may be unnecessarily putting those EU citizens at an increased risk of exposure.