Bisphenol A: A Concise Review of Literature and a Discussion of Health and Regulatory Implications

The Effects of Short- and Long-Term Ingestion of Plastic Toxin Bisphenol A on Gastrointestinal Transit Time in Rats

Introduction Exposure to bisphenol A (BPA), a toxic chemical released from plastic, affects various body functions, including reproduction, metabolism, and development. The most common route of exposure to BPA is oral, and the gastrointestinal (GI) tract is, therefore, the first body system to be exposed to BPA. BPA has been well-documented to impair gut contractility in rats, in vitro. It may therefore be hypothesized that BPA may adversely affect GI motility and hence slow down the movement of food, resulting in the increased transit of food bolus in the GI tract. There are no reports so far on the effects of BPA on GI transit time. Objectives The present study was undertaken to examine the impact of exposure to BPA by a single oral dose (termed as short-term ingestion of BPA) and chronic (28-day) oral dose (termed as long-term ingestion of BPA) on the transit time of food bolus in the gut of adult male albino rats. Methods and materials The study was conducted in the Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India. In one set of experiments, each animal was fed a food pellet, once (short-term ingestion) containing BPA (2 µg/kg and 50 µg/kg in different groups), and in another set of experiments, each animal was fed a food pellet containing BPA (50 µg/kg/day) for 28 consecutive days (long-term ingestion). Control rats in both sets were fed food pellets without BPA. Subsequently, the gastric transit index (GTI), ileocecal transit index (ICTI), and colonic transit time (CTT) were determined by the standard charcoal marker method. Results One-time ingestion of a food pellet containing BPA caused a significant (p < 0.05) drop in the GTI and ICTI and an increase in the CTT with both doses of BPA (2 and 50 µg/kg). Similarly, after chronic (28-day), oral BPA exposure, a significant decrease in the GTI and ICTT and an increase in CTT were observed. Conclusion Both short-term (one-time) and long-term (28-day) oral exposure to BPA-containing food harmed GI transit. Slow GI transit may lead to metabolic disorders and GI motility disorders, such as constipation.

Ameliorative effect of vitamin E and selenium against bisphenol A-induced toxicity in spinal cord and submandibular salivary glands of adult male albino rats

Bisphenol A (BPA) used in plastic industry. This study evaluate ameliorative effect of vitamin E and selenium in combating BPA toxicity in spinal cord (SC) and submandibular glands (SMGs). Thirty rats divided into three groups [Group I, controls; Group II, BPA orally (25 mg/kg) three times a week, 60 days; Group III, BPA (25 mg/kg) plus vitamin E and selenium in water (1 ml/L/day)]. By histopathological, immunohistochemical, and biochemical investigations. Bisphenol A group showed degenerative alterations. SC gray matter showed pyknotic nuclei and white matter revealed neuropil degeneration. Myelinated fibers showed dispersed myelin. SMGs, exhibited vacuolated cytoplasm in acinar cells. Intense glial fibrillary acidic protein in SC and strong proliferating cell nuclear antigen in acinar and ductal cell nuclei of SMGs. Malondialdehyde elevated in SC and catalase decreased in SMG. Group III, SC and SMG revealed partial recovery. Vitamin E and selenium displayed protective effects against BPA toxicity in SC and SMGs.

Understanding microplastic pollution of marine ecosystem: a review

Microplastics are emerging as prominent pollutants across the globe. Oceans are becoming major sinks for these pollutants, and their presence is widespread in coastal regions, oceanic surface waters, water column, and sediments. Studies have revealed that microplastics cause serious threats to the marine ecosystem as well as human beings. In the past few years, many research efforts have focused on studying different aspects relating to microplastic pollution of the oceans. This review summarizes sources, migration routes, and ill effects of marine microplastic pollution along with various conventional as well as advanced methods for microplastics analysis and control. However, various knowledge gaps in detection and analysis require attention in order to understand the sources and transport of microplastics, which is critical to deploying mitigation strategies at appropriate locations. Advanced removal methods and an integrated approach are necessary, including government policies and stringent regulations to control the release of plastics.

BPA interferes with granulosa cell development and oocyte meiosis in mouse preantral follicles

Bisphenol A (BPA) is an established environmental endocrine disruptor and can interfere with the development of female germ cells. However, the underlying mechanisms are still unclear. We investigated the effects of BPA on granulosa cell development and meiosis of oocytes using in vitro culture system of mouse preantral follicles. Preantral follicles from D14 mouse ovary were treated with 10 μg/mL BPA in vitro for 11 days. The adherent area of follicles was measured. On D11, cumulus cell expansion was observed. The meiosis recovery rate was calculated. Western blot detected P53, proliferating cell nuclear antigen (PCNA), estrogen receptor α (ERα), and cyclin B1. ELISA measured estrogen and progesterone levels. Immunofluorescence detected Cx37 on oocyte membrane. Gap junction communication was assessed. We found that BPA significantly promoted the expressions of PCNA and ERα in granulosa cells and the secretion of estrogen and progesterone by granulosa cells on D10 and significantly increased the attachment area of the follicles on D8 and D10. However, it reduced the expansion of cumulus cells, Cx37 expression, and the gap junction communication between cumulus cells and oocytes on D11. BPA promoted the recovery of oocytes from meiosis, interrupted the expression of cyclin B1 protein in arrested germinal vesicle breakdown (GVBD) oocytes, and reduced the in vitro maturation rate of oocytes. These GVBD oocytes were live without apoptosis or death. Conclusively, BPA disturbs the development of granulosa cells and the meiosis progression of oocytes by decreasing gap junction communication between oocytes and the granulosa cells as well as regulating cyclin B1 expression in GVBD oocytes.

Effects of prenatal exposure to bisphenols on newborn leucocyte telomere length: a prospective birth cohort study in China

Telomere length (TL) at birth is related to diseases that may arise in the future and long-term health. Bisphenols exhibit toxic effects and can cross the placenta barrier. However, the effects of prenatal exposure to bisphenols on newborn TL remain unknown. We aimed to explore the effects of prenatal exposure to bisphenols (i.e., bisphenol A [BPA], bisphenol B [BPB], bisphenol F [BPF], bisphenol S [BPS] and tetrabromobisphenol A [TBBPA]) on relative TL in newborns. A total of 801 mother-infant pairs were extracted from the Guangxi Zhuang Birth Cohort. The relationship between bisphenol levels in maternal serum and relative TL in cord blood was examined by generalized linear models and restricted cubic spline (RCS) models. After adjusting for confounders, we observed a 3.19% (95% CI: -6.08%, -0.21%; P = 0.037) reduction in relative cord blood TL among mothers ≥ 28 years old, with each onefold increase in BPS. However, in each onefold increase of TBBPA, we observed a 3.31% (95% CI: 0.67%, 6.01%; P = 0.014) increase in relative cord blood TL among mothers < 28 years old. The adjusted RCS models revealed similar results (P overall < 0.05, P non-linear > 0.05). This study was the first to establish a positive association between serum TBBPA levels and relative TL in newborns born to young mothers. However, BPS levels were inversely correlated with TL in fetus born to old mothers. The results suggested that the fetus of old pregnant women may be more sensitive to BPS exposure. Moreover, BPS exposure early in life may accelerate aging or increase the risk of developing BPS-related diseases in later life.

Changes in the Enteric Neurons Containing Selected Active Substances in the Porcine Descending Colon after the Administration of Bisphenol A (BPA)

Bisphenol A (BPA) is an endocrine disruptor widely distributed in the environment due to its common use in the plastics industry. It is known that it has a strong negative effect on human and animal organisms, but a lot of aspects of this impact are still unexplored. This includes the impact of BPA on the enteric nervous system (ENS) in the large intestine. Therefore, the aim of the study was to investigate the influence of various doses of BPA on the neurons located in the descending colon of the domestic pig, which due to similarities in the organization of intestinal innervation to the human gastrointestinal tract is a good animal model to study processes occurring in human ENS. During this study, the double immunofluorescence technique was used. The obtained results have shown that BPA clearly affects the neurochemical characterization of the enteric neurons located in the descending colon. The administration of BPA caused an increase in the number of enteric neurons containing substance P (SP) and vasoactive intestinal polypeptide (VIP) with a simultaneously decrease in the number of neurons positive for galanin (GAL) and vesicular acetylcholine transporter (VAChT used as a marker of cholinergic neurons). Changes were noted in all types of the enteric plexuses, i.e., the myenteric plexus, outer submucous plexus and inner submucous plexus. The intensity of changes depended on the dose of BPA and the type of enteric plexus studied. The results have shown that BPA may affect the descending colon through the changes in neurochemical characterization of the enteric neurons located in this segment of the gastrointestinal tract.

New approach methods for assessing indoor air toxicity

Indoor air is typically a mixture of many chemicals at low concentrations without any adverse health effects alone, but in mixtures they may cause toxicity and risks to human health. The aim of this study was by using new approach methods to assess the potential toxicity of indoor air condensates. In specific, different in vitro test methods including cyto-and immunotoxicity, skin sensitization and endocrine disruption were applied. In addition to biological effects, the indoor air samples were subjected to targeted analysis of 25 volatile organic compounds (VOCs) and Genapol X-80 (a nonionic emulsifier) suspected to be present in the samples, and to a non-targeted "total chemical scan" to find out whether the chemical composition of the samples is associated with the biological effects. The results confirm that assessing health risks of indoor air by analysing individual chemicals is not an adequate approach: We were not able to detect the VOCs and Genapol X-80 in the indoor air samples, yet, several types of toxicity, namely, cytotoxicity, immunotoxicity, skin sensitization and endocrine disruption were detected. In the non-targeted total chemical scan of the indoor air samples, a larger number of compounds were found in the cytotoxic samples than in the non-cytotoxic samples supporting the biological findings. If only one biological method would be selected for the screening of indoor air quality, THP-1 macrophage/WST-1 assay would best fit for the purpose as it is sensitive and serves as a good representative for different sub-toxic end points, including immunotoxicity, (skin) sensitization and endocrine disruption.

Role of Nrf2 in bisphenol effects: a review study

Bisphenols (BPs), the main endocrine-disrupting chemicals used in polycarbonate plastics, epoxy-phenol resins, and some other manufacturers, have been interestingly focused to find their toxic effects in recent years. Due to the strong relation between bisphenols and some crucial receptors such as ERs, AR, glucocorticoid receptor, THRs, ERRs, hPXR, AhR, and etcetera, the disrupting and oncogenic role of these chemicals on reproductive, respiratory, and circulatory systems and a broad group of body tissues have been investigated. BPs induce oxidant enzymes, exert antioxidant enzymes from body cells, and result in the expression of proinflammatory genes, leading to cell apoptosis and inflammation. To maintain the homeostasis of human body cells, Nrf2, the key regulator of oxidative stress (Ashrafizadeh et al., 2020a; Ashrafizadeh et al., 2020c; Boroumand et al., 2018), confronts BP-induced ROS and RNS through the activation of antioxidant enzymes such as SOD1/2, CAT, GSH, GPX, HO-1, and etcetera. Chemicals and drugs such as LUT, NAC, GEN, L-NMMA, Ph₂Se₂, and GE can regulate the interactions between BPs and Nrf2. Despite the vital role of controlled levels of Nrf2 as an anti-inflammatory and antiapoptotic element, the uncontrolled activity of this transcription factor could lead to cell proliferation and tumorigenesis through NQO1, SLC7a11, Gclm, HMOX1, NQO1 gene activation, and some other genes. To avoid the excessive activity of Nrf2, some protein complexes like CUL3-RBX1-Keap1 (as the primary regulator), β-TrCP, and WDR23 regulate Nrf2's function. It is necessary to note that BPA, as the most famous member, is further reviewed due to its resemblance to the bisphenol family to each other.

Survey on endocrine-disrupting chemicals in seafood: Occurrence and distribution

Currently, the presence of endocrine disrupting chemicals (EDCs) in the marine environment pose а potential risk to both wildlife and human health. The occurrence of EDCs in seafood depends of several factors such as source and amounts of EDCs that reach the aquatic environment, physicochemical features of EDCs, and its accumulation in trophic chain. This review highlights the occurrence and distribution of EDCs along the seafood in the last 6 years. The following EDCs were included in this review: brominated flame retardants (PBDEs, PBBs, HBCDDs, TBBPA, and novel flame retardants); pharmaceuticals (paracetamol, ibuprofen, diclofenac, carbamazepine), bisphenols, hormones, personal care products (Musk and UV Filters), and pesticides (organochlorides, organophosphates, and pyrethroids). Some of them were found above the threshold that may cause negative effects on human, animal, and environmental health. More control in some countries, as well as new legislation and inspection over the purchase, sale, use, and production of these compounds, are urgently needed. This review provides data to support risk assessment and raises critical gaps to stimulate and improve future research.

Low concentrations of bisphenol A promote the activation of the mitochondrial apoptotic pathway on Beta-TC-6 cells via the generation of intracellular reactive oxygen species and mitochondrial superoxide

Τhe natural history of type 2 diabetes mellitus is characterized by a progressive loss of pancreatic beta cell function and insulin resistance. Bisphenol A (BPA) is an endocrine-disrupting chemical that is used widely in industry; people are exposed to BPA and its products daily. Studies have delineated that BPA alters the function of pancreatic beta cells. Herein, we examined the effect of low doses of BPA on pancreatic beta cell viability and apoptosis and we tried to elucidate the mechanisms involved in these processes. Beta-TC-6 (ATCC® CRL-11506™) cells were cultured with a medium containing the following dilutions of BPA: 0.002, 0.02, 0.1, 0.2, 2 μΜ up to 72 h. We examined the viability and adenosine triphosphate (ATP) levels of cells. Then, we measured apoptosis, cell cycle, and insulin levels. We quantified the levels of proteins implicated in the mitochondrial pathway of apoptosis; and finally, we quantified the intracellular reactive oxygen species and mitochondrial superoxide. We found that the exposure of Beta-TC-6 cells to BPA results in a decrease in cell viability, ATP levels, and an increase in insulin levels. We found an increase in apoptosis levels and a decrease in cell cycle levels. In addition, we provide evidence of the levels of apoptotic proteins. Finally, we found an increase in the cellular reactive oxygen species and mitochondrial superoxide production. Exposure to low concentrations of BPA triggers the mitochondrial pathway of apoptosis via the generation of intracellular reactive oxygen species and mitochondrial superoxide on Beta-TC-6 cells in a dose-dependent way.

Can Exposure to Environmental Pollutants Be Associated with Less Effective Chemotherapy in Cancer Patients?

Since environmental pollutants are ubiquitous and many of them are resistant to degradation, we are exposed to many of them on a daily basis. Notably, these pollutants can have harmful effects on our health and be linked to the development of disease. Epidemiological evidence together with a better understanding of the mechanisms that link toxic substances with the development of diseases, suggest that exposure to some environmental pollutants can lead to an increased risk of developing cancer. Furthermore, several studies have raised the role of low-dose exposure to environmental pollutants in cancer progression. However, little is known about how these compounds influence the treatments given to cancer patients. In this work, we present a series of evidences suggesting that environmental pollutants such as bisphenol A (BPA), benzo[a]pyrene (BaP), persistent organic pollutants (POPs), aluminum chloride (AlCl₃), and airborne particulate matter may reduce the efficacy of some common chemotherapeutic drugs used in different types of cancer. We discuss the potential underlying molecular mechanisms that lead to the generation of this chemoresistance, such as apoptosis evasion, DNA damage repair, activation of pro-cancer signaling pathways, drug efflux and action of antioxidant enzymes, among others.

Cell components, interaction types and functional groups involved in the in vitro binding of bisphenol A by Lactiplantibacillus plantarum RS20D and DL7X

AIMS

The current study aimed to evaluate the capacity of two Lactiplantibacillus plantarum strains to remove Bisphenol A (BPA) and to determine the preliminary removal mechanisms underlying this process.

METHODS AND RESULTS

The BPA removal capacity of L. plantarum RS20D and DL7X was assessed by HPLC analysis. The effect of various treatments (physical, chemical, and enzymatic) on two strains were studied to understand which interaction types worked. The different cellular components of them were also subjected to binding assays. Additionally, Fourier-transform infrared spectroscopy (FTIR) was performed to identify the functional groups related to the BPA binding process. Results show that various treatments enhanced the binding capacity of two strains, the effect of sodium dodecyl sulfate was the most outstanding (P=0.000, P=0.000). Hydrogen bonding and hydrophobic interactions likely occurred. Peptidoglycans showed the highest binding capability, protoplasts and teichoic acids might also exert a binding effect. -OH, C=O, -CH, -NH, C-N, C-O, and P=O participated in BPA binding by the two L. plantarum lines.

CONCLUSIONS

Peptidoglycans, protoplasts, and teichoic acid played a vital role in the binding of BPA.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results provided a theoretical foundation for developing effective dietary strategies with foodborne L. plantarum to remove food contaminants.

Men´s reproductive alterations caused by bisphenol A and its analogues: a review

Male reproductive functions are an important area affecting men´s overall health and well-being. However, during the last years, there has been observed increasing incidence of male reproductive issues. The radical growth has been recorded parallelly with a massive expanse of industrialization and agricultural chemigation. Many groups of experts have begun to identify several potential factors and substances that may have adverse effects on men´s reproductive health. Since then, xenobiotics have become a major concern of many scientific studies. There is evidence that most of them have multigenerational and transgenerational effects on reproductive health, which is a serious problem for our population. Bisphenol A could be considered as one of the most studied endocrine disruptors. Until now, several negative effects of bisphenol A were associated with reduced weight testes, histological alterations, impairment spermatogenesis, and steroidogenesis as well as with testes or prostate cancer. Due to convincing evidence, bisphenol A has been started to replace by its analogues such as bisphenol B, S, F, in order to eliminate and suppress the risk of exposure to bisphenol A. However, it seems that a lack of toxicological analyses allows using of these hazardous substances in daily life. Their harmful effect was confirmed by the animal in vitro and in vivo models, while the epidemiological studies monitoring the impact of bisphenol analogues on men's reproductive health are markedly limited. This review provides information about the effects of bisphenol on reproductive health in men. At the same time, it is focused on physiological aspects of sperm viability, steroid hormone secretion, sperm motility, or testes histology in relation to bisphenols exposure.

Intestinal toxicity and microbial community disorder induced by bisphenol F and bisphenol S in zebrafish

The intestine is the important bioaccumulation and target organ of Bisphenol F (BPF) and Bisphenol S (BPS). Morphological and functional abnormalities induced by BPS and BPF exposure in zebrafish intestine have been reported. However, the underlying mechanisms are not well understood, and the combined toxicities of BPS and BPF in the intestine have not been studied. Here, the zebrafish were treated by single and combined exposure of BPF and BPS at 1, 10, 100, 1000 μg/L. Oxidative damage, inflammation, and transcriptome profiles in the zebrafish intestine were determined. Changes in microbial community structure in zebrafish intestine were analyzed. Results showed that BPF, BPS, and BPF + BPS exposures significantly increased MDA, 8-OHdG, 1L-1β, and TNF-α levels in the zebrafish intestine, indicating oxidative damage and inflammatory effects. Co-exposure of BPS and BPF did not cause synergistic effects on the above effects but induced more changes in gene expression profiles. The changes in the PPAR signaling pathway might be associated with oxidative damage and inflammation. The amino acid metabolism and steroid biosynthesis were specifically altered by co-exposure of BPF and BPS. Moreover, BPF and/or BPS exposures altered microbial community structure in the zebrafish intestine, which showed different influence patterns. Increased abundance of potentially pathogenic bacteria (such as Flavobacterium, Pseudomonas, and Stenotrophomonas) might indicate one of the potential health hazards in zebrafish intestine. The above results provide basic information for the health risk assessment of BPS and BPF in aquatic organisms.

Bisphenol A removal and degradation pathways in microorganisms with probiotic properties

Bisphenol-A (BPA) is a constituent of polycarbonate plastics and epoxy resins, widely applied on food packaging materials. As BPA exposure results in health hazards, its efficient removal is of crucial importance. In our study five potentially probiotic microorganisms, namely Lactococcus lactis, Bacillus subtilis, Lactobacillus plantarum, Enterococcus faecalis, and Saccharomyces cerevisiae, were tested for their toxicity tolerance to BPA and their BPA removal ability. Although BPA toxicity, evident on all microorganisms, presented a correlation to both BPA addition time and its concentration, all strains exhibited BPA-removal ability with increased removal rate between 0 and 24 h of incubation. BPA degradation resulted in the formation of two dimer products in cells while the compounds Hydroquinone (HQ), 4-Hydroxyacetophenone (HAP), 4-Hydroxybenzoic acid (HBA) and 4-Isopropenylphenol (PP) were identified in the culture medium. In the proposed BPA degradation pathways BPA adducts formation appears as a common pattern, while BPA decomposition as well as the formation, and the levels of its end products present differences among microorganisms. The BPA degradation ability of the tested beneficial microorganisms demonstrates their potential application in the bioremediation of BPA contaminated foods and feeds and provides a means to suppress the adverse effects of BPA on human and animal health.

Bisphenol-A inhibits mitochondrial biogenesis via impairment of GFER mediated mitochondrial protein import in the rat brain hippocampus

Mitochondrial biogenesis relies on different protein import machinery, as mitochondrial proteins are imported from the cytosol. The mitochondrial intermembrane space assembly (MIA) pathway consists of GFER/ALR and CHCHD4/Mia40, responsible for importing proteins and their oxidative folding inside the mitochondria. The MIA pathway plays an essential role in complex IV (COX IV) biogenesis via importing copper chaperone COX17, associated with the respiratory chain. BPA, an environmental toxicant, found in consumable plastics, causes neurotoxicity via impairment in mitochondrial dynamics, neurogenesis, and cognitive functions. We studied the levels of key regulatory proteins of mitochondrial import pathways and mitochondrial biogenesis after BPA exposure in the rat hippocampus. BPA caused a significant reduction in the levels of mitochondrial biogenesis proteins (PGC1α, and TFAM) and mitochondrial import protein (GFER). Immunohistochemical analysis showed reduced co-localization of NeuN with GFER, PGC-1α, and TFAM suggesting impaired mitochondrial biogenesis and protein import. BPA exposure resulted in damaged mitochondria with distorted cristae in neurons and caused a significant reduction in GFER localization inside IMS as depicted by immunogold electron microscopy. The reduced levels of GFER resulted in defective COX17 import. The translocation of cytochrome c into the cytosol and increased cleaved caspase-3 levels triggered apoptosis due to BPA toxicity. Overall, our study implicates GFER as a potential target for impaired mitochondrial protein machinery, biogenesis, and apoptosis against BPA neurotoxicity in the rat hippocampus.

Placing nanoplastics in the context of global plastic pollution

Numerous studies have made the ubiquitous presence of plastic in the environment undeniable, and thus it no longer comes as a surprise when scientists measure the accumulation of macroplastic litter and microplastic fragments in both urban and remote sites. Nanoplastics have recently emerged in the discussions of scientists, regulators and the public, as the weathering of macroplastics may lead to a substantial burden of nanoplastics in various ecosystems. While nanoplastics particles themselves have not (yet) been extensively measured in the environment, there is increased concern that this size fraction of plastic may be more extensively distributed and hazardous that larger-sized particles. This assessment may emanate from an unease with the term 'nano', which may elicit a negative response over uncertainties of the pervasiveness of nanoplastics specifically, or from the lessons learned by many years of intensive environmental health and safety research of engineered nanomaterials. Ultimately, the different physical and chemical characteristics of the different size classes of plastic pollution (macroplastics, microplastics and nanoplastics) will result in divergent fate and hazards. As nanoscientists specializing in understanding the fate, transport and interactions of nanoparticles in human and environmental systems, in this Perspective, we try to place nanoplastics in the context of global plastic pollution by assessing its sources and risks, and by assessing commonalities nanoplastics may share with other nanosized objects in environmental systems, such as engineered nanomaterials and natural colloids.

Dietary Intake of Endocrine Disrupting Substances Presents in Environment and Their Impact on Thyroid Function

According to the available data, environmental pollution is a serious problem all over the world. Between 2015 and 2016, pollution was responsible for approximately nine million deaths worldwide. They also include endocrine disrupting chemicals (EDCs) that can interfere with the functioning of the thyroid gland. They are characterized by high persistence in the environment. These substances can enter the body through the gastrointestinal tract, respiratory system, as well as contact with the skin and overcome the placental barrier. EDC can be found in food, water, and personal care products. They can get into food from the environment and as a result of their migration to food products and cosmetics from packaging. EDCs can disrupt the functioning of the thyroid gland through a number of mechanisms, including disrupting the activation of thyroid receptors and the expression of genes that are related to the metabolism, synthesis, and transport of thyroid hormones (HT). There is a need to strengthen the food safety policy that aimed at the use of appropriate materials in direct contact with food. At the same time, an important action is to reduce the production of all waste and, when possible, use biodegradable packaging, which may contribute to the improvement of the quality of the entire ecosystem and the health of food, thus reducing the risk of developing thyroid diseases.

The Putative Adverse Effects of Bisphenol A on Autoimmune Diseases

Bisphenol A (BPA) is a monomer that is widely used in the manufacture of polycarbonate plastics including storage plastics and baby bottles, and is considered one of the most widely used synthetic compounds in the manufacturing industry. Exposure to BPA mainly occurs after oral ingestion and results from leaks into food and water from plastic containers and according to epidemiological data exposure is widespread and estimated to occur in 90% of individuals. BPA exertspleiotropiceffects and demonstrates estrogen like effects, thus considered an endocrine disrupting chemical. Growing body of evidence highlight the role of BPA in modulating immune responses and signaling pathways resulting in a proinflammatory response by enhancing the differential polarization of immune cells and cytokine production profile to one that is consistent with proinflammation. Indeed, epidemiological studies have uncovered associations between several autoimmune diseases and BPA exposure. Data from animal models provided consistent evidence highlighting the role of BPA in the pathogenesis, exacerbation and perpetuation of various autoimmune phenomena including neuroinflammation in the context of multiple sclerosis, colitis in inflammatory bowel disease, nephritis in systemic lupus erythematosus, and insulitis in type 1 diabetes mellitus. Given the wide spread of BPA use and its effects in immune systemdysregulation, a call for careful assessment of patients' risks and for public health measures are needed to limit exposure and subsequent deleterious effects. The purpose of this paper is to explore the autoimmune triggering mechanisms and present the current literature supporting the role of BPA in the pathogenesis of autoimmune diseases.

Low-Dose Bisphenol A in a Rat Model of Endometrial Cancer: A CLARITY-BPA Study

BACKGROUND

Bisphenol A (BPA) is known to be biologically active in experimental models even at low levels of exposure. However, its impact on endometrial cancer remains unclear.

OBJECTIVES

This study aimed to investigate whether lifelong exposure to different doses of BPA induced uterine abnormalities and molecular changes in a rat model.

METHODS

Sprague-Dawley rats were exposed to 5 doses of BPA [0, 25, 250, 2,500, or 25,000 μ g / kg body weight (BW)/d] or 2 doses of 17 α - ethynylestradiol (EE2) (0.05 and 0.5 μ g / kg BW/d) starting from gestational day 6 up to 1 y old according to the CLARITY-BPA consortium protocol. The BW, uterus weight, and histopathology end points of the uteri were analyzed at postnatal (PND) day 21, 90, and 365. Estrous cycling status was evaluated in PND90 and PND365 rats. Transcriptomic analyses of estrus stage uteri were conducted on PND365 rats.

RESULTS

Based on the analysis of the combined effects of all testing outcomes (including immunohistological, morphological, and estrous cycle data) in a semiblinded fashion, using statistical models, 25 μ g / kg BW/d BPA [BPA(25)], or 250 μ g / kg BW/d BPA [BPA(250)] exerted effects similar to that of EE2 at 0.5 μ g / kg BW/d in 1-y-old rats. Transcriptome analyses of estrus stage uteri revealed a set of 710 genes shared only between the BPA(25) and BPA(250) groups, with 115 of them predicted to be regulated by estradiol and 57 associated with female cancers. An interesting finding is that the expression of 476 human orthologous genes in this rat BPA signature robustly predicted the overall survival (p = 1.68 × 10 - 5 , hazard ratio = 2.62 ) of endometrial cancer patients.

DISCUSSION

Lifelong exposure of rats to low-dose BPA at 25 and 250 μ g / kg BW/d altered the estrous cycle and uterine pathology with similarity to EE2. The exposure also disrupted a unique low-dose BPA-gene signature with predictive value for survival outcomes in patients with endometrial cancer. https://doi.org/10.1289/EHP6875.

Bisphenols and Risk of Breast Cancer: A Narrative Review of the Impact of Diet and Bioactive Food Components

Data from preclinical studies suggest a link between increased risk of breast cancer and exposure to bisphenols at doses below what the United States Food and Drug Administration (FDA) considers as safe for consumption. Bisphenols exert estrogenic effects and are found in canned and plastic wrapped foods, food packaging, and plasticware. Mechanistically, bisphenols bind to the estrogen receptor (ER) and activate the expression of genes associated with cell proliferation and breast cancer. In this paper, we present a narrative literature review addressing bisphenol A and chemical analogs including bisphenol AF, bisphenol F, and bisphenol S selected as prototype xenoestrogens; then, we discuss biological mechanisms of action of these bisphenols in breast cells and potential impact of exposure at different stages of development (i.e., perinatal, peripubertal, and adult). Finally, we summarize studies detailing interactions, both preventative and promoting, of bisphenols with food components on breast cancer risk. We conclude the review with a discussion of current controversies in interpretation of the above research and future areas for investigation, including the impact of bisphenols and food components on breast tumor risk.

Bisphenol A (BPA)-Induced Changes in the Number of Serotonin-Positive Cells in the Mucosal Layer of Porcine Small Intestine-the Preliminary Studies

Bisphenol A (BPA) is a substance used in the production of plastics which has a negative impact on many internal organs. Because BPA is normally toxic for the gastrointestinal (GI) tract, the intestine is especially vulnerable to the adverse effects of this substance. The aim of this investigation was to study the influence of two doses of BPA (0.05 mg and 0.5 mg/kg body weight/day) on the number of mucosal cells in the porcine small intestine and containing serotonin (5-hydroxytryptamine, 5-HT). During the experiment, it was demonstrated that both applied BPA doses caused an increase in the number of 5-HT-positive cells located in the mucosal layer of the duodenum, jejunum, and ileum. These changes may be connected with the direct impact of BPA on the intestinal mucosa, the pro-inflammatory and immunomodulatory properties of this substance, and/or the influence of BPA on the neurochemical characterization of nervous structures supplying the intestine.