Mammalian development in a changing environment: exposure to endocrine disruptors reveals the developmental plasticity of steroid-hormone target organs

Exploring novel insights into the molecular mechanisms underlying Bisphenol A-induced toxicity: A persistent threat to human health

Bisphenol A (BPA) is a ubiquitous industrial chemical used in the production of polycarbonate plastics and epoxy resins, found in numerous consumer products. Despite its widespread use, its potential adverse health effects have raised significant concerns. This review explores the molecular mechanisms and evidence-based literature underlying BPA-induced toxicities and its implications for human health. BPA is an endocrine-disrupting chemical (EDC) which exhibits carcinogenic properties by influencing various receptors, such as ER, AhR, PPARs, LXRs, and RARs. It induces oxidative stress and contributes to cellular dysfunction, inflammation, and DNA damage, ultimately leading to various toxicities including but not limited to reproductive, cardiotoxicity, neurotoxicity, and endocrine toxicity. Moreover, BPA can modify DNA methylation patterns, histone modifications, and non-coding RNA expression, leading to epigenetic changes and contribute to carcinogenesis. Overall, understanding molecular mechanisms of BPA-induced toxicity is crucial for developing effective strategies and policies to mitigate its adverse effects on human health.

Impact of DEHP exposure on female reproductive health: Insights into uterine effects

Several endocrine disrupting compounds released from plastics, including polyfluoroalkyl substances, bisphenols, flame retardants, phthalates and others, are of great concern to human health due to their high toxicity. This review discusses the effects of di-(2-ethylhexyl) phthalate (DEHP), the most common member of the phthalate family, on female reproduction. In vitro and in vivo studies link DEHP exposure to impaired hypothalamic-pituitary-ovarian s (HPO) axis function, alteration of steroid-hormone levels and dysregulation of their receptors, and changes in uterine morphophysiology. In addition, high urinary DEPH levels have been associated with several reproductive disorders in women, including endometriosis, fibromyoma, fetal growth restriction and pregnancy loss. These data suggest that DEHP may be involved in the pathophysiology of various female reproductive diseases. Therefore, exposure to these compounds should be considered a concern in clinician surveillance practices for women at reproductive age and should be regulated to protect their health and that of their progeny.

Evaluating endocrine disrupting chemicals: A perspective on the novel assessments in CLARITY-BPA

BACKGROUND

The Consortium Linking Academic and Regulatory Insights on Bisphenol A Toxicity (CLARITY-BPA) was a collaborative research effort to better link academic research with governmental guideline studies. This review explores the secondary goal of CLARITY-BPA: to identify endpoints or technologies from CLARITY-BPA and prior/concurrent literature from these laboratories that may enhance the capacity of rodent toxicity studies to detect endocrine disrupting chemicals (EDCs).

METHODS

A systematic literature search was conducted with search terms for BPA and the CLARITY-BPA participants. Relevant studies employed a laboratory rodent model and reported results on 1 of the 10 organs/organ systems evaluated in CLARITY-BPA (brain and behavior, cardiac, immune, mammary gland, ovary, penile function, prostate gland and urethra, testis and epididymis, thyroid hormone and metabolism, and uterus). Study design and findings were summarized, and a risk-of-bias assessment was conducted.

RESULTS

Several endpoints and methods were identified as potentially helpful to detect effects of EDCs. For example, molecular and quantitative morphological approaches were sensitive in detecting alterations in early postnatal development of the brain, ovary, and mammary glands. Hormone challenge studies mimicking human aging reported increased susceptibility of the prostate to disease following developmental BPA exposure. Statistical analyses for nonmonotonic dose responses, and computational approaches assessing multiple treatment-related outcomes concurrently in linked hormone-sensitive organ systems, reported effects at low BPA doses.

CONCLUSIONS

This review provided an opportunity to evaluate the unique insights provided by nontraditional assessments in CLARITY-BPA to identify technologies and endpoints to enhance detection of EDCs in future studies.

NTS, NTSR1 and ERs in the Pituitary-Gonadal Axis of Cycling and Postnatal Female Rats after BPA Treatment

The neuropeptide neurotensin (NTS) is involved in regulating the reproductive axis and is expressed at each level of this axis (hypothalamus-pituitary-gonads). This dependence on estrogen levels has been widely demonstrated in the hypothalamus and pituitary. We focused on confirming the relationship of NTS with estrogens and the gonadal axis, using a particularly important environmental estrogenic molecule, bisphenol-A (BPA). Based on the experimental models or in vitro cell studies, it has been shown that BPA can negatively affect reproductive function. We studied for the first time the action of an exogenous estrogenic substance on the expression of NTS and estrogen receptors in the pituitary-gonadal axis during prolonged in vivo exposure. The exposure to BPA at 0.5 and 2 mg/kg body weight per day during gestation and lactation was monitored through indirect immunohistochemical procedures applied to the pituitary and ovary sections. Our results demonstrate that BPA induces alterations in the reproductive axis of the offspring, mainly after the first postnatal week. The rat pups exposed to BPA exhibited accelerated sexual maturation to puberty. There was no effect on the number of rats born per litter, although the fewer primordial follicles suggest a shorter fertile life.

Hepatic Transcriptome Analysis Reveals Genes, Polymorphisms, and Molecules Related to Lamb Tenderness

Tenderness is a key meat quality trait that determines the public acceptance of lamb consumption, so genetic improvement toward lamb with higher tenderness is pivotal for a sustainable sheep industry. However, unravelling the genomics controlling the tenderness is the first step. Therefore, this study aimed to identify the transcriptome signatures and polymorphisms related to divergent lamb tenderness using RNA deep sequencing. Since the molecules and enzymes that control muscle growth and tenderness are metabolized and synthesized in the liver, hepatic tissues of ten sheep with divergent phenotypes: five high- and five low-lamb tenderness samples were applied for deep sequencing. Sequence analysis identified the number of reads ranged from 21.37 to 25.37 million bases with a mean value of 22.90 million bases. In total, 328 genes are detected as differentially expressed (DEGs) including 110 and 218 genes that were up- and down-regulated, respectively. Pathway analysis showed steroid hormone biosynthesis as the dominant pathway behind the lamb tenderness. Gene expression analysis identified the top high (such as TP53INP1, CYP2E1, HSD17B13, ADH1C, and LPIN1) and low (such as ANGPTL2, IGFBP7, FABP5, OLFML3, and THOC5) expressed candidate genes. Polymorphism and association analysis revealed that mutation in OLFML3, ANGPTL2, and THOC5 genes could be potential candidate markers for tenderness in sheep. The genes and pathways identified in this study cause variation in tenderness, thus could be potential genetic markers to improve meat quality in sheep. However, further validation is needed to confirm the effect of these markers in different sheep populations so that these could be used in a selection program for lamb with high tenderness.

Multi-omics approaches for remediation of bisphenol A: Toxicity, risk analysis, road blocks and research perspectives

In this "plastic era" with the increased use of plastic in day today's life the accumulation of its degraded products like microplastics or plastic additives such as Bisphenol A(BPA) is also increasing. BPA is an endocrine-disrupting chemical used as a plasticizing agent in clear plastic, building materials, coatings, and epoxy resin. Several enzymes including laccases and lipases have been studied for the reduction of BPA toxicity. Over the decades of encountering these toxicants, microorganisms have evolved to degrade different classes of plastic additives. Since the degradation of BPA is a long process thus meta-omics approaches have been employed to identify the active microbiota and microbial dynamics involved in the mitigation of BPA. It is also necessary to investigate the impact of processing activities on transit of BPA in food items and to limit its entrance in food world. This review summarizes a comprehensive overview on BPA sources, toxicity, bio-based mitigation approaches along with a deeper understanding of multi-omics approaches for its reduction and risk analysis. Knowledge gaps and opportunities have been comprehensively compiled that would aid the state-of-the-art information in the available literature for the researchers to further address this issue.

Stable magnetic CoZn/N-doped polyhedron with self-generating carbon nanotubes for highly efficient removal of bisphenols from complex wastewaters

Bisphenols have extensively been found in various environmental matrices and caused public concerns due to their endocrine-disrupting potential. Herein, we developed a ZIF-67@ZIF-8-derived CoZn/nitrogen-doped carbon (CoZn/NC) as a robust adsorbent for bisphenols in wastewaters. The self-generating carbon nanotubes and the open metal sites provided sufficient adsorption sites. The Co component endowed the derivative with strong magnetism facilitating its separation from water. CoZn/NC exhibited exceeding water stability in pH 3 - 12 solution and withstood water up to 15 days. The great applicability of CoZn/NC was validated with 16 real wastewaters from different sources (recoveries exceeding 97.9%). Fast adsorption kinetics were observed with removal efficiencies above 96.5% within 1 min. The adsorption isotherms were well fitted with the Langmuir model, with adsorption capacities of 222, 200, 193, and 321 mg g^-1 for bisphenol A, bisphenol F, bisphenol S, and bisphenol AF, respectively. Variations in external conditions, including pH 3 - 9, humic acid (50 mg L^-1), and NaCl (0.1 mol L^-1), had negligible impacts on the adsorption process. The characterizations and density functional theory computation demonstrated that electrostatic, hydrophobic, π - π, and cation- π interactions are the driving forces in this system. The as-prepared CoZn/NC exhibits great promise in real wastewater treatment.

Implications of endocrine-disrupting chemicals on polycystic ovarian syndrome: A comprehensive review

Polycystic ovarian syndrome (PCOS) is a complex multifactorial disorder of unknown pathogenesis in which genetic and environmental factors contribute synergistically to its phenotypic expressions. Endocrine-disrupting chemicals (EDCs), a group of widespread pollutants freely available in the environment and consumer products, can interfere with normal endocrine signals. Extensive evidence has shown that EDCs, environmental contributors to PCOS, can frequently induce ovarian and metabolic abnormalities at low doses. The current research on environmental EDCs suggests that there may be link between EDC exposure and PCOS, which calls for more human bio-monitoring of EDCs using highly sophisticated analytical techniques for the identification and quantification and to discover the underlying pathophysiology of the disease. This review briefly elaborated on the general etiology of PCOS and listed various epidemiological and experimental data from human and animal studies correlating EDCs and PCOS. This review also provides insights into various analytical tools and sample preparation techniques for biomonitoring studies for PCOS risk assessment. Furthermore, we highlight the role of metabolomics in disease-specific biomarker discovery and its use in clinical practice. It also suggests the way forward to integrate biomonitoring studies and metabolomics to underpin the role of EDCs in PCOS pathophysiology.

Impact of Environmentally Relevant Concentrations of Bisphenol A (BPA) on the Gene Expression Profile in an In Vitro Model of the Normal Human Ovary

Endocrine-disrupting chemicals (EDCs), including the xenoestrogen Bisphenol A (BPA), can interfere with hormonal signalling. Despite increasing reports of adverse health effects associated with exposure to EDCs, there are limited data on the effect of BPA in normal human ovaries. In this paper, we present a detailed analysis of the transcriptomic landscape in normal Human Epithelial Ovarian Cells (HOSEpiC) treated with BPA (10 and 100 nM). Gene expression profiles were determined using high-throughput RNA sequencing, followed by functional analyses using bioinformatics tools. In total, 272 and 454 differentially expressed genes (DEGs) were identified in 10 and 100 nM BPA-treated HOSEpiCs, respectively, compared to untreated controls. Biological pathways included mRNA surveillance pathways, oocyte meiosis, cellular senescence, and transcriptional misregulation in cancer. BPA exposure has a considerable impact on 10 genes: ANAPC2, AURKA, CDK1, CCNA2, CCNB1, PLK1, BUB1, KIF22, PDE3B, and CCNB3, which are also associated with progesterone-mediated oocyte maturation pathways. Future studies should further explore the effects of BPA and its metabolites in the ovaries in health and disease, making use of validated in vitro and in vivo models to generate data that will address existing knowledge gaps in basic biology, hazard characterisation, and risk assessment associated with the use of xenoestrogens such as BPA.

Killing two birds with one stone: Pregnancy is a sensitive window for endocrine effects on both the mother and the fetus

Pregnancy is a complex process requiring tremendous physiological changes in the mother in order to fulfill the needs of the growing fetus, and to give birth, expel the placenta and nurse the newborn. These physiological modifications are accompanied with psychological changes, as well as with variations in habits and behaviors. As a result, this period of life is considered as a sensitive window as impaired functional and physiological changes in the mother can have short- and long-term impacts on her health. In addition, dysregulation of the placenta and of mechanisms governing placentation have been linked to chronic diseases later-on in life for the fetus, in a concept known as the Developmental Origin of Health and Diseases (DOHaD). This concept stipulates that any change in the environment during the pre-conception and perinatal (in utero life and neonatal) period to puberty, can be "imprinted" in the organism, thereby impacting the health and risk of chronic diseases later in life. Pregnancy is a succession of events that is regulated, in large part, by hormones and growth factors. Therefore, small changes in hormonal balance can have important effects on both the mother and the developing fetus. An increasing number of studies demonstrate that exposure to endocrine disrupting compounds (EDCs) affect both the mother and the fetus giving rise to growing concerns surrounding these exposures. This review will give an overview of changes that happen during pregnancy with respect to the mother, the placenta, and the fetus, and of the current literature regarding the effects of EDCs during this specific sensitive window of exposure.

Developmental Programming: Prenatal Testosterone Excess on Liver and Muscle Coding and Noncoding RNA in Female Sheep

Prenatal testosterone (T)-treated female sheep manifest peripheral insulin resistance, ectopic lipid accumulation, and insulin signaling disruption in liver and muscle. This study investigated transcriptional changes and transcriptome signature of prenatal T excess-induced hepatic and muscle-specific metabolic disruptions. Genome-wide coding and noncoding (nc) RNA expression in liver and muscle from 21-month-old prenatal T-treated (T propionate 100 mg intramuscular twice weekly from days 30-90 of gestation; term: 147 days) and control females were compared. Prenatal T (1) induced differential expression of messenger RNAs (mRNAs) in liver (15 down, 17 up) and muscle (66 down, 176 up) (false discovery rate < 0.05, absolute log2 fold change > 0.5); (2) downregulated mitochondrial pathway genes in liver and muscle; (3) downregulated hepatic lipid catabolism and peroxisome proliferator-activated receptor (PPAR) signaling gene pathways; (4) modulated noncoding RNA (ncRNA) metabolic processes gene pathway in muscle; and (5) downregulated 5 uncharacterized long noncoding RNA (lncRNA) in the muscle but no ncRNA changes in the liver. Correlation analysis showed downregulation of lncRNAs LOC114112974 and LOC105607806 was associated with decreased TPK1, and LOC114113790 with increased ZNF470 expression. Orthogonal projections to latent structures discriminant analysis identified mRNAs HADHA and SLC25A45, and microRNAs MIR154A, MIR25, and MIR487B in the liver and ARIH1 and ITCH and miRNAs MIR369, MIR10A, and MIR10B in muscle as potential biomarkers of prenatal T excess. These findings suggest downregulation of mitochondria, lipid catabolism, and PPAR signaling genes in the liver and dysregulation of mitochondrial and ncRNA gene pathways in muscle are contributors of lipotoxic and insulin-resistant hepatic and muscle phenotype. Gestational T excess programming of metabolic dysfunctions involve tissue-specific ncRNA-modulated transcriptional changes.

Bisphenol-A exposure and risk of breast and prostate cancer in the Spanish European Prospective Investigation into Cancer and Nutrition study

BACKGROUND

Bisphenol A (BPA) is an endocrine disruptor that it is present in numerous products of daily use. The aim of this study was to assess the potential association of serum BPA concentrations and the risk of incident breast and prostate cancer in a sub-cohort of the Spanish European Prospective Investigation into Cancer and Nutrition (EPIC).

METHODS

We designed a case-cohort study within the EPIC-Spain cohort. Study population consisted on 4812 participants from 4 EPIC-Spain centers (547 breast cancer cases, 575 prostate cancer cases and 3690 sub-cohort participants). BPA exposure was assessed by means of chemical analyses of serum samples collected at recruitment. Borgan II weighted Cox regression was used to estimate hazard ratios.

RESULTS

Median follow-up time in our study was 16.9 years. BPA geometric mean serum values of cases and sub-cohort were 1.12 ng/ml vs 1.10 ng/ml respectively for breast cancer and 1.33 ng/ml vs 1.29 ng/ml respectively for prostate cancer. When categorizing BPA into tertiles, a 40% increase in risk of prostate cancer for tertile 1 (p = 0.022), 37% increase for tertile 2 (p = 0.034) and 31% increase for tertile 3 (p = 0.072) was observed with respect to values bellow the limit of detection. No significant association was observed between BPA levels and breast cancer risk.

CONCLUSIONS

We found a similar percentage of detection of BPA among cases and sub-cohort from our population, and no association with breast cancer risk was observed. However, we found a higher risk of prostate cancer for the increase in serum BPA levels. Further investigation is needed to understand the influence of BPA in prostate cancer risk.

Endocrine disrupting chemicals and the mammary gland

Development of the mammary gland requires coordination of hormone signaling pathways including those mediated by estrogen, progesterone, androgen and prolactin receptors. These hormones play important roles at several distinct stages of life including embryonic/fetal development, puberty, pregnancy, lactation, and old age. This also makes the gland sensitive to perturbations from environmental agents including endocrine disrupting chemicals (EDCs). Although there is evidence from human populations of associations between EDCs and disruptions to breast development and lactation, these studies are often complicated by the timing of exposure assessments and the latency to develop breast diseases (e.g., years to decades). Rodents have been instrumental in providing insights-not only to the basic biology and endocrinology of the mammary gland, but to the effects of EDCs on this tissue at different stages of development. Studies, mostly but not exclusively, of estrogenic EDCs have shown that the mammary gland is a sensitive tissue, that exposures during perinatal development can produce abnormal mammary structures (e.g., alveolar buds, typically seen in pregnant females) in adulthood; that exposures during pregnancy can alter milk production; and that EDC exposures can enhance the response of the mammary tissue to hormones and chemical carcinogens. Other studies of persistent organic pollutants have shown that EDC exposures during critical windows of development can delay development of the gland, with lifelong consequences for the individual. Collectively, this work continues to support the conclusion that EDCs can harm the mammary gland, with effects that depend on the period of exposure and the period of evaluation.

Endocrine disrupting chemical Bisphenol A and its potential effects on female health

BACKGROUND AND AIM

A large number of chemical compounds with endocrine-disrupting activity have been documented. These chemicals are ubiquitous and widely used in many products of our daily lives. Bisphenol A (BPA) is among the most common Endocrine Disrupting Chemical (EDC) that has been used for many years in the manufacture of polycarbonate plastics and epoxy resins. There is growing evidence that exposure to these EDCs poses a possible health risk. This review focuses on the effect of EDCs, in particular, BPA on female reproduction and Polycystic Ovary Syndrome (PCOS), which is the most prevalent endocrine disorder of reproductively aged women.

METHODS

A relevant literature survey was conducted with Google scholar and Pubmed using several appropriate keywords to select the most relevant studies evaluating the role of endocrine disrupting-chemicals in female reproduction.

RESULTS

The female menstrual cycle and fertility are very sensitive to hormonal imbalance and alteration in endocrine function during critical times and different stages of lifecycle owing to EDC exposure results in many abnormalities like menstrual irregularities, impaired fertility, PCOS, and Endometriosis among others. BPA is the most extensively studied EDC worldwide and has been strongly associated with female reproductive health.

CONCLUSION

EDCs lead to deleterious effects on human health including reproductive health which are of global concern. Exposure to EDCs in early life can elicit disease in adult life and maybe even transgenerational. There is an immediate need to minimize the ill effect of EDCs which can be tackled through the collection of more data to clarify the clinical implications of EDCs.

Environmental exposures to endocrine disrupting chemicals (EDCs) and their role in endometriosis: a systematic literature review

PURPOSE

Endocrine-related diseases and disorders are on the rise globally. Synthetically produced environmental chemicals (endocrine-disrupting chemicals (EDCs)) mimic hormones like oestrogen and alter signalling pathways. Endometriosis is an oestrogen-dependent condition, affecting 10-15% of women of the reproductive age, and has substantial impacts on the quality of life. The aetiology of endometriosis is believed to be multifactorial, ranging from genetic causes to immunologic dysfunction due to environmental exposure to EDCs. Hence, we undertook a systematic review and investigated the epidemiological evidence for an association between EDCs and the development of endometriosis. We also aimed to assess studies on the relationship between body concentration of EDCs and the severity of endometriosis.

METHOD

Following PRISMA guidelines, a structured search of PubMed, Embase and Scopus was conducted (to July 2018). The included studies analysed the association between one or more EDCs and the prevalence of endometriosis. The types of EDCs, association and outcome, participant characteristics and confounding variables were extracted and analysed. Quality assessment was performed using standard criteria.

RESULTS

In total, 29 studies were included. Phthalate esters were positively associated with the prevalence of endometriosis. The majority (71%) of studies revealed a significant association between bisphenol A, organochlorinated environmental pollutants (dioxins, dioxin-like compounds, organochlorinated pesticides, polychlorinated biphenyls) and the prevalence of endometriosis. A positive association between copper, chromium and prevalence of endometriosis was demonstrated in one study only. Cadmium, lead and mercury were not associated with the prevalence of endometriosis. There were conflicting results for the association between nickel and endometriosis. The relationship of EDCs and severity of endometriosis was not established in the studies.

CONCLUSION

We found some evidence to suggest an association between phthalate esters, bisphenol A, organochlorinated environmental pollutants and the prevalence of endometriosis. Disentangling these exposures from various other factors that affect endometriosis is complex, but an important topic for further research.

Comparative toxicity reduction potential of UV/sodium percarbonate and UV/hydrogen peroxide treatments for bisphenol A in water: An integrated analysis using chemical, computational, biological, and metabolomic approaches

Bisphenol A (BPA) is a common industrial chemical with significant adverse impacts on biological systems as an environmental contaminant. UV/hydrogen peroxide (UV/H₂O₂) is a well-established technology for BPA treatment in water while UV/sodium percarbonate (UV/SPC) is an emerging technology with unclear biological impacts of treated effluent. Therefore, in this study, the toxicity evaluation of BPA solution treated with UV/H₂O₂ and UV/SPC was preformed and compared based on transformation products (TPs) profile, quantitative structure-activity relationship (QSAR), Escherichia coli (E. coli) toxicity assays, and metabolomic analysis. TPs with hydroxylation, double-ring split, and single-ring cleavage were generated from BPA during the treatments with both technologies, but TPs with quinonation were specifically detected in UV/H₂O₂ treated solution at the UV dose of 1470 mJ cm^-2. QSAR prediction based on TPs profile (excluding benzoquinone TPs) suggested that UV/H₂O₂ and UV/SPC treatments of BPA may increase matrix toxicity due to the formation of multi-hydroxylated TPs; however decreased bioaccumulation potential of all TPs may mitigate the increase of toxicity by reducing the chance of TPs to reach the concentration of toxicity threshold. In vivo assays with E. coli showed inhibited cell growth, arrested cell cycle, and increased cell death in BPA solution treated with UV/H₂O₂ at the UV dose of 1470 mJ cm^-2. Metabolomic analysis indicated that BPA solution treated with UV/H₂O₂ at UV dose of 1470 mJ cm^-2 impacted E. coli metabolism differently than other solutions with unique inhibition on glycerolipid metabolism. Moreover, BPA interfered in various metabolic pathways including alanine, aspartate and glutamate metabolism, starch and sucrose metabolism, pentose phosphate pathway, and lysine degradation, which were mitigated after the treatments. UV/SPC showed advantage over UV/H₂O₂ of attenuated impact on butanoate metabolism with UV irradiation. This study has generated valuable data for better understanding of biological impacts of BPA and its solutions treated with UV/H₂O₂ or UV/SPC, thus providing insights for their application prospect for water and wastewater treatment.

Bisphenol A and Bisphenol S Induce Endocrine and Chromosomal Alterations in Brown Trout

Bisphenol A is a widely used compound found in large amount of consumer products. As concerns have been raised about its toxicological and public health effect, the use of alternatives to bisphenol A are now increasing. Bisphenol S is one of the analogues being used as a replacement for bisphenol A despite the fact that little is known about the effects of bisphenol S on living organisms. In this study, we investigated the potential endocrine and genotoxic effects of bisphenol A and bisphenol S in juvenile brown trout (Salmo trutta). The fish were exposed to the compounds for either 2 weeks or 8 weeks via sustained-release cholesterol implants containing doses of 2 mg/kg fish or 20 mg/kg fish of the substances. The effects on the thyroid hormone levels and the estrogenic disrupting marker vitellogenin were evaluated, along with the genotoxic markers micronucleated cells and erythrocyte nuclear abnormalities. An increase in plasma vitellogenin was observed in fish exposed to the high dose of bisphenol A for 2 weeks. At this experimental time the level of the thyroid hormone triiodothyronine (T3) in plasma was elevated after bisphenol S exposure at the high concentration, and paralleled by an increase of micronucleated cells. Moreover, bisphenol A induced an increase of micronuclei frequency in fish erythrocytes after the exposure at the lowest dose tested. Taken together the results indicate that both bisphenol A and its alternative bisphenol S cause endocrine disrupting and genotoxic effects in brown trout, although suggesting two different mechanisms of damage underlying bisphenol A and bisphenol S activity.

Data integration, analysis, and interpretation of eight academic CLARITY-BPA studies

"Consortium Linking Academic and Regulatory Insights on BPA Toxicity" (CLARITY-BPA) was a comprehensive "industry-standard" Good Laboratory Practice (GLP)-compliant 2-year chronic exposure study of bisphenol A (BPA) toxicity that was supplemented by hypothesis-driven independent investigator-initiated studies. The investigator-initiated studies were focused on integrating disease-associated, molecular, and physiological endpoints previously found by academic scientists into an industry standard guideline-compliant toxicity study. Thus, the goal of this collaboration was to provide a more comprehensive dataset upon which to base safety standards and to determine whether industry-standard tests are as sensitive and predictive as molecular and disease-associated endpoints. The goal of this report is to integrate the findings from the investigator-initiated studies into a comprehensive overview of the observed impacts of BPA across the multiple organs and systems analyzed. For each organ system, we provide the rationale for the study, an overview of methodology, and summarize major findings. We then compare the results of the CLARITY-BPA studies across organ systems with the results of previous peer-reviewed studies from independent labs. Finally, we discuss potential influences that contributed to differences between studies. Developmental exposure to BPA can lead to adverse effects in multiple organs systems, including the brain, prostate gland, urinary tract, ovary, mammary gland, and heart. As published previously, many effects were at the lowest dose tested, 2.5μg/kg /day, and many of the responses were non-monotonic. Because the low dose of BPA affected endpoints in the same animals across organs evaluated in different labs, we conclude that these are biologically - and toxicologically - relevant.

Bisphenol-A and polycystic ovary syndrome: a review of the literature

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among women of reproductive age with reproductive, metabolic and endocrine implications. While the exact pathophysiological mechanisms of the syndrome are unknown, its heterogeneity suggests a multifactorial causal background. In the last two decades, numerous environmental chemicals, including Bisphenol-A (BPA) that is used in the synthesis of polycarbonate plastics, have been proposed as potential contributors to the aetiology of PCOS. This review provides a holistic overview of the available data regarding the possible relation of PCOS with BPA exposure. We have included a total number of 24 studies. Eleven human case-control and 13 animal studies provided data regarding this potential relation. Accumulating evidence suggests that a correlation between high levels of BPA and the presence of PCOS may exist. Contradicting results from human and animal studies, however, render it difficult to conclude on the exact role of BPA in the pathogenesis of PCOS. BPA may constitute a consequence of the syndrome rather than a cause, but further research is still needed to clarify this. Continued efforts to study the early origins of PCOS, using prospective-designed studies, are required to identify the exact effect of BPA on women with PCOS.

Carcinogenic effects of bisphenol A in breast and ovarian cancers

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

Developmental programming: Prenatal testosterone-induced changes in epigenetic modulators and gene expression in metabolic tissues of female sheep

Prenatal testosterone (T)-treated female sheep manifest peripheral insulin resistance and tissue-specific changes in insulin sensitivity with liver and muscle manifesting insulin resistance accompanied by inflammatory, oxidative and lipotoxic state. In contrast, visceral (VAT) and subcutaneous (SAT) adipose tissues are insulin sensitive in spite of VAT manifesting changes in inflammatory and oxidative state. We hypothesized that prenatal T-induced changes in tissue-specific insulin resistance arise from disrupted lipid storage and metabolism gene expression driven by changes in DNA and histone modifying enzymes. Changes in gene expression were assessed in liver, muscle and 4 adipose (VAT, SAT, epicardiac [ECAT] and perirenal [PRAT]) depots collected from control and prenatal T-treated female sheep. Prenatal T-treatment increased lipid droplet and metabolism genes PPARA and PLIN1 in liver, SREBF and PLIN1 in muscle and showed a trend for decrease in PLIN2 in PRAT. Among epigenetic modifying enzymes, prenatal T-treatment increased expression of 1) DNMT1 in liver and DNMT3A in VAT, PRAT, muscle and liver; 2) HDAC1 in ECAT, HDAC2 in muscle with decrease in HDAC3 in VAT; 3) EP300 in VAT and ECAT; and 4) KDM1A in VAT with increases in liver histone acetylation. Increased lipid storage and metabolism genes in liver and muscle are consistent with lipotoxicity in these tissues with increased histone acetylation likely contributing to increased liver PPARA. These findings are suggestive that metabolic defects in prenatal T-treated sheep may arise from changes in key genes mediated, in part, by tissue-specific changes in epigenetic-modifying enzymes.

Sex-Specific Differences of Steroid Receptors Following Exposure to Environmentally Relevant Concentrations of Phenothiazine in Fundulus heteroclitus

Phenothiazine (PTZ) is a heterocyclic thiazine compound used for industrial and medical purposes. Through environmental surveillance studies, PTZ was found being discharged into a local river in Connecticut. Phenothiazine has been shown to act similarly to endocrine disrupting chemicals. This study sought to identify sex specific hormone receptor changes in Fundulus heteroclitus in response to PTZ exposure. Fundulus heteroclitus, also known as mummichog, are small fish native to the Atlantic coast of the United States and Canada. They reside in brackish waters and can survive harsh toxic environments. This model organism is native to the polluted waters found in Connecticut. In this study, fish were exposed to PTZ concentrations of 0.5 ppm, 1.0 ppm, and 2.0 ppm for 1 week. Following exposure, brain, liver, and gonad tissues were harvested; cDNA was synthesized; and mRNA expression was assessed for 6 different hormone receptors. Compared with vehicle control (ethanol) differences in mRNA expression, levels of hormone receptors were observed in various tissues from male and female fish. Many of the tissues assessed showed changes in expression level, while only female liver and testis showed no change. These results implicate PTZ as a potential endocrine disrupting compound to mummichog at environmentally relevant concentrations.

Role of Antioxidants in Alleviating Bisphenol A Toxicity

Bisphenol A (BPA) is an oestrogenic endocrine disruptor widely used in the production of certain plastics, e.g., polycarbonate, hard and clear plastics, and epoxy resins that act as protective coating for food and beverage cans. Human exposure to this chemical is thought to be ubiquitous. BPA alters endocrine function, thereby causing many diseases in human and animals. In the last few decades, studies exploring the mechanism of BPA activity revealed a direct link between BPA-induced oxidative stress and disease pathogenesis. Antioxidants, reducing agents that prevent cellular oxidation reactions, can protect BPA toxicity. Although the important role of antioxidants in minimizing BPA stress has been demonstrated in many studies, a clear consensus on the associated mechanisms is needed, as well as the directives on their efficacy and safety. Herein, considering the distinct biochemical properties of BPA and antioxidants, we provide a framework for understanding how antioxidants alleviate BPA-associated stress. We summarize the current knowledge on the biological function of enzymatic and non-enzymatic antioxidants, and discuss their practical potential as BPA-detoxifying agents.

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.

A Method Validation for Simultaneous Determination of Phthalates and Bisphenol A Released from Plastic Water Containers

Phthalates (or phthalate esters, PAEs) and bisphenol A (BPA) are widely used in various industries, particularly in the fields of cosmetics and packaging, and they increase the malleability and workability of materials. As a result of their use, some international health organizations have begun to study them. In this study, the authors developed a methodology for the simultaneous determination of dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DiBP); dibutyl phthalate (DBP), bis(2-ethylhexyl) phthalate (DEHP); di-n-octyl-phthalate (DnOP) and bisphenol A (BPA) from drinking and non-potable waters. The extraction of PAEs and BPA was performed using a solvent-based dispersive liquid–liquid microextraction (SB-DLLME) method. The analytical determination was performed using a gas chromatography–ion trap mass spectrometry (GC-IT/MS) analysis. The entire procedure was validated as recoveries were studied according to the volume and the extraction solvent used, pH, and ionic strength. Dynamic linearity ranges and linear equations of all the compounds were experimentally determined as well as the limit of detection (LOD) (1–8 ng mL−1) and the limit of quantification (LOQ) (5–14 ng mL−1), reproducibility, and sensitivity. The method was applied to 15 water samples (mineral water and tap water) for determining PAEs and BPA released from the plastic container. After the release simulation, four PAEs (i.e., DiBP, DBP, DHEP, and DnOP) were determined at very low concentrations (below 1.2 ng mL−1) in two water samples from (sport) bottles.

Prenatal epigenetics diets play protective roles against environmental pollution

It is thought that germ cells and preimplantation embryos during development are most susceptible to endogenous and exogenous environmental factors because the epigenome in those cells is undergoing dramatic elimination and reconstruction. Exposure to environmental factors such as nutrition, climate, stress, pathogens, toxins, and even social behavior during gametogenesis and early embryogenesis has been shown to influence disease susceptibility in the offspring. Early-life epigenetic modifications, which determine the expression of genetic information stored in the genome, are viewed as one of the general mechanisms linking prenatal exposure and phenotypic changes later in life. From atmospheric pollution, endocrine-disrupting chemicals to heavy metals, research increasingly suggests that environmental pollutions have already produced significant consequences on human health. Moreover, mounting evidence now links such pollution to relevant modification in the epigenome. The epigenetics diet, referring to a class of bioactive dietary compounds such as isothiocyanates in broccoli, genistein in soybean, resveratrol in grape, epigallocatechin-3-gallate in green tea, and ascorbic acid in fruits, has been shown to modify the epigenome leading to beneficial health outcomes. This review will primarily focus on the causes and consequences of prenatal environment pollution exposure on the epigenome, and the potential protective role of the epigenetics diet, which could play a central role in neutralizing epigenomic aberrations against environmental pollutions.

Association of exposure to Bisphenol A with obesity and cardiometabolic risk factors in children and adolescents

In this study, the association of exposure to Bisphenol A (BPA) with obesity and cardiometabolic risk factors was investigated on 132 children and adolescents aged 6-18 years living in Isfahan, Iran. Potential contributors to BPA exposure were assessed by a questionnaire. Total BPA was detected in urine samples of all participants without significant difference in boys and girls. The mean body mass index (BMI) and waist circumference (WC) increased significantly across the BPA tertiles (p for trend = < 0.001). Similar trend was documented for systolic blood pressure (SBP) and diastolic blood pressure (DBP) as well as fasting blood sugar. The risk of obesity was 12.48 times higher in participants in the third tertile of BPA than in others (95% CI: 3.36-46.39, p < 0.001). The current study showed significant association between BPA exposure with obesity and some cardiometabolic risk factors in children and adolescents, however, further longitudinal studies are necessary to evaluate the clinical effects of this finding. Abbreviations: BMI: Body Mass Index; BPA: Bisphenol A; BSTFA: N, O-Bistrifluoroacetamide; CDC: Centers for Disease Control and Prevention; CI: Circumference Interval; DBP: Diastolic Blood Pressure; DLLME: Dispersive liquid-liquid microextraction method; FBS: Fasting Blood Glucose; HDL: high-density lipoprotein cholesterol were; LDL: low-density lipoprotein cholesterol; OR: Odd Ratio; PA: Physical Activity; SBP: Systolic Blood Pressure; TC: total cholesterol; TG: triglycerides; WC: Waist Circumference.

The Case for BPA as an Obesogen: Contributors to the Controversy

Since the inception of the term endocrine disruptor, the idea that the environment is an important determinant of phenotype has motivated researchers to explore the effect of low dose exposure to BPA during organogenesis. The syndrome observed was complex, affecting various endpoints such as reproduction and reproductive tissues, behavior, mammary gland development and carcinogenesis, glucose homeostasis, and obesity. This constellation of impacted endpoints suggests the possibility of complex interactions among the multiple effects of early BPA exposure. One key finding of our rodent studies was alterations of energy and amino-acid metabolism that were detected soon after birth and continued to be present at all time points examined through 6 months of age. The classical manifestations of obesity and associated elements of metabolic disease took a longer time to become apparent. Here we examine the validity of the often-mentioned lack of reproducibility of obesogenic effects of BPA, starting from the known environmental causes of variation, which are diverse and range from the theoretical like the individuation process and the non-monotonicity of the dose-response curve, to the very pragmatic like housing, feed, and time and route of exposure. We then explore environmental conditions that may hinder reproducibility and discuss the effect of confounding factors such as BPA-induced hyperactivity. In spite of all the potential sources of variation, we find that some obesogenic or metabolic effects of BPA are reproducibly observed when study conditions are analogous. We recommend that study authors describe details of their study conditions including the environment, husbandry, and feed. Finally, we show that when experimental conditions are strictly maintained, reproducibility, and stability of the obese phenotype is consistently observed.

Protective role of Ficus deltoidea against BPA-induced impairments of the follicular development, estrous cycle, gonadotropin and sex steroid hormones level of prepubertal rats

Ficus deltoidea is one of the well-known medicinal plants in Malaysia that is traditionally used by the Malay community to treat various ailments and for maintenance of female reproductive health. The objective of this study is to evaluate the potential protective roles of Ficus deltoidea against BPA-induced toxicity of the pituitary-ovarian axis in pre-pubertal female rats. In this study, four groups of pre-pubertal female Sprague Dawley rats were administered with the followings by oral gavage for a period of six weeks: NC (negative control- treated with vehicle), PC (positive control-treated with BPA at 10 mg/kg/BW), F (treated with Ficus deltoidea at 100 mg/kg/BW, then exposed to BPA at 10 mg/kg/BW) and FC (Ficus deltoidea control - treated with Ficus deltoidea at 100 mg/kg/BW). Daily vaginal smear, ovarian follicular development as well as gonadotropin and sexual-steroid hormone levels were determined. The findings showed that Ficus deltoidea demonstrated preventive role against BPA-induced toxicity on the ovaries. This was evident by the increased percentage of rats with normal estrous cycle, qualitatively reduced number of atretic follicles (as observed in histopathological examination) and normalization of the gonadotropins hormone (FSH) and sexual steroid hormone (progesterone) levels. In conclusion, Ficus deltoidea has the capability to prevent the effects of BPA toxicity in the hypothalamus-pituitary-gonadal axis of prepubertal female reproductive system, possibly due to its variety of phytochemical properties. Therefore, these findings strongly support the traditional belief that this medicinal plant is beneficial as daily dietary supplement for the maintenance of female reproductive health.

Alteration of mammary gland development by bisphenol a and evidence of a mode of action mediated through endocrine disruption

The development and function of the mammary gland are endocrine-dependent processes, depending on the stage of development. Foetal and/or postnatal exposure to low doses of BPA alters tissue organisation through epithelial proliferation and stroma-epithelial interactions. BPA also alters the expression of E2-dependent epithelial and stroma transcriptomes. Several signalling pathways are consistent with the observed phenotype: proliferation and apoptosis, a focal adhesion pathway indicating changes in biomechanical properties of the extracellular matrix, and immune function. Some of BPA's effects are reversed by oestrogen and/or GPER inhibitors. BPA also alters the expression of epigenetic marks (EZH2, HOTAIR), which would explain the delayed effect of foetal BPA exposure. In conclusion, experimental evidence shows that pre- or postnatal BPA exposure consistently causes endocrine modifications in the mammary tissue of different animal species, disrupting stromal-epithelial interactions and ultimately increasing its susceptibility to carcinogens. An interspecies comparison highlights why and how these effects apply to humans.

Prenatal Steroids and Metabolic Dysfunction: Lessons from Sheep

Prenatal exposure to excess steroids or steroid mimics can disrupt the normal developmental trajectory of organ systems, culminating in adult disease. The metabolic system is particularly susceptible to the deleterious effects of prenatal steroid excess. Studies in sheep demonstrate that prenatal exposure to excess native steroids or endocrine-disrupting chemicals with steroidogenic activity, such as bisphenol A, results in postnatal development of numerous cardiometabolic perturbations, including insulin resistance, increased adiposity, altered adipocyte size and distribution, and hypertension. The similarities in the phenotypic outcomes programmed by these different prenatal insults suggest that common mechanisms may be involved, and these may include hormonal imbalances (e.g., hyperandrogenism and hyperinsulinemia), oxidative stress, inflammation, lipotoxicity, and epigenetic alterations. Animal models, including the sheep, provide mechanistic insight into the metabolic repercussions associated with prenatal steroid exposure and represent valuable research tools in understanding human health and disease. Focusing on the sheep model, this review summarizes the cardiometabolic perturbations programmed by prenatal exposure to different native steroids and steroid mimics and discusses the potential mechanisms underlying the development of adverse outcomes.

Perinatal BPA exposure and reproductive axis function in CD-1 mice

Perinatal Bisphenol-A (BPA) exposure reduces fertility and fecundity in mice. This study examined effects of early BPA exposure on activation of gonadotropin releasing hormone (GnRH) neurons in conjunction with a steroid-induced luteinizing hormone (LH) surge, characterized patterns of estrous cyclicity and fertility over time, and assessed the ovarian follicular reserve to further explore factors responsible for the reduced fertility we previously described in this model. The percent activated GnRH neurons was reduced in BPA-exposed females at 3-6 months, and periods of persistent proestrus were increased. These data suggest that perinatal exposure to BPA reduces GnRH neuronal activation required for the generation of the LH surge and estrous cyclicity. Assessments of anti-Müllerian hormone (AMH) levels failed to suggest a decline in the follicular reserve at the BPA exposure levels examined.

Comparative effects of Bisphenol S and Bisphenol A on the development of female reproductive system in rats; a neonatal exposure study

Bisphenol A (BPA) has been well documented for its endocrine disrupting potential however, very little is known about endocrine disrupting abilities of bisphenol S (BPS). The present study aimed to compare the endocrine disrupting potentials of BPS with BPA, using female rats as an experimental animal model. On postnatal day 1 (PND 1) female pups born were randomly assigned to seven different treatments. Control group received subcutaneous injection of castor oil (50 μL) from PND 1 to PND 10. Three groups of female pups were injected subcutaneously with different concentrations (0.5, 5 and 50 mg/kg in 50 μL castor oil) of BPS, while remaining three groups were treated with 0.5, 5 and 50 mg/kg BPA. Highest doses treatments of both compounds resulted in delayed puberty onset and altered estrous cyclicity. Final body weight was significantly high in the highest dose treated groups of both BPS and BPA. Gonadosomatic index, absolute and relative weight of uteri was significantly reduced in BPS (5 and 50 mg/kg) and BPA (5 and 50 mg/kg) treated groups than control. Plasma concentrations of testosterone and estradiol were significantly increased, while plasma progesterone, Luteinizing hormone (LH) and Follicle stimulating hormone (FSH) concentrations were significantly reduced in highest doses treated groups. Dose dependent increase in the number of cystic follicles in the ovaries was evident along with an increase in the number of atratic follicles. The results suggest that neonatal exposure to higher concentrations of BPS can lead to BPA like structural and endocrine alterations in female rats.

Prenatal Exposure to Unconventional Oil and Gas Operation Chemical Mixtures Altered Mammary Gland Development in Adult Female Mice

Unconventional oil and gas (UOG) operations, which combine hydraulic fracturing (fracking) and directional drilling, involve the use of hundreds of chemicals, including many with endocrine-disrupting properties. Two previous studies examined mice exposed during early development to a 23-chemical mixture of UOG compounds (UOG-MIX) commonly used or produced in the process. Both male and female offspring exposed prenatally to one or more doses of UOG-MIX displayed alterations to endocrine organ function and serum hormone concentrations. We hypothesized that prenatal UOG-MIX exposure would similarly disrupt development of the mouse mammary gland. Female C57Bl/6 mice were exposed to ~3, ~30, ~ 300, or ~3000 μg/kg/d UOG-MIX from gestational day 11 to birth. Although no effects were observed on the mammary glands of these females before puberty, in early adulthood, females exposed to 300 or 3000 μg/kg/d UOG-MIX developed more dense mammary epithelial ducts; females exposed to 3 μg/kg/d UOG-MIX had an altered ratio of apoptosis to proliferation in the mammary epithelium. Furthermore, adult females from all UOG-MIX-treated groups developed intraductal hyperplasia that resembled terminal end buds (i.e., highly proliferative structures typically seen at puberty). These results suggest that the mammary gland is sensitive to mixtures of chemicals used in UOG production at exposure levels that are environmentally relevant. The effect of these findings on the long-term health of the mammary gland, including its lactational capacity and its risk of cancer, should be evaluated in future studies.

Developmental Programming of Ovarian Functions and Dysfunctions

The pathophysiological mechanisms underlying the origin of several ovarian pathologies remain unclear. In addition to the genetic basis, developmental insults are gaining attention as a basis for the origin of these pathologies. Such early insults include maternal over or under nutrition, stress, and exposure to environmental chemicals. This chapter reviews the development and physiological function of the ovary, the known ovarian pathologies, the developmental check points of ovarian differentiation impacted by developmental insults, the role played by steroidal and metabolic factors as mediaries, the epigenetic mechanisms via which these mediaries induce their effects, and the knowledge gaps for targeting future studies to ultimately aid in the development of improved treatments.

Scientific Challenges in the Risk Assessment of Food Contact Materials

BACKGROUND

Food contact articles (FCAs) are manufactured from food contact materials (FCMs) that include plastics, paper, metal, glass, and printing inks. Chemicals can migrate from FCAs into food during storage, processing, and transportation. Food contact materials' safety is evaluated using chemical risk assessment (RA). Several challenges to the RA of FCAs exist.

OBJECTIVES

We review regulatory requirements for RA of FCMs in the United States and Europe, identify gaps in RA, and highlight opportunities for improving the protection of public health. We intend to initiate a discussion in the wider scientific community to enhance the safety of food contact articles.

DISCUSSION

Based on our evaluation of the evidence, we conclude that current regulations are insufficient for addressing chemical exposures from FCAs. RA currently focuses on monomers and additives used in the manufacture of products, but it does not cover all substances formed in the production processes. Several factors hamper effective RA for many FCMs, including a lack of information on chemical identity, inadequate assessment of hazardous properties, and missing exposure data. Companies make decisions about the safety of some food contact chemicals (FCCs) without review by public authorities. Some chemical migration limits cannot be enforced because analytical standards are unavailable.

CONCLUSION

We think that exposures to hazardous substances migrating from FCAs require more attention. We recommend a) limiting the number and types of chemicals authorized for manufacture and b) developing novel approaches for assessing the safety of chemicals in FCAs, including unidentified chemicals that form during or after production. https://doi.org/10.1289/EHP644.

Exposure to modern, widespread environmental endocrine disrupting chemicals and their effect on the reproductive potential of women: an overview of current epidemiological evidence

Growing evidence indicates that exposure to widespread, environmental contaminants called endocrine disruptors (EDCs) negatively affects animal and human reproductive health and has been linked to several diseases including infertility. This review aims to evaluate the impact of environmental exposure to endocrine disrupting chemicals [phthalates, parabens, triclosan, bisphenol A (BPA), organochlorine (PCBs) and perfluorinated (PFCs) compounds] on the reproductive potential among women, by reviewing most recently published literature. Epidemiological studies focusing on EDCs exposure and reproductive potential among women for the last 16 years were identified by a search of the PUBMED, MEDLINE, EBSCO and TOXNET literature databases. The results of the presented studies show that exposure to EDCs impacts the reproductive potential in women, measured by ovarian reserve and by assisted reproductive technology outcomes. Exposure to environmental endocrine disrupting chemicals decrease: (i) oestradiol levels (BPA); (ii) anti-Müllerian hormone concentrations (PCBs); (iii) antral follicle count (BPA, parabens, phthalates); (iv) oocyte quality (BPA, triclosan, phthalates, PCBs); (v) fertilization rate (PFCs, PCBs); (vi) implantation (BPA, phthalates, PCBs); (vii) embryo quality (triclosan, PCBs, BPA); (viii) rate of clinical pregnancy and live births (parabens, phthalates). The studies were mostly well-designed and used prospective cohorts with the exposure assessment based on the biomarker of exposure. Considering the suggested health effects, more epidemiological data is urgently needed to confirm the presented findings.

The Genetic Architecture of Ovariole Number in Drosophila melanogaster: Genes with Major, Quantitative, and Pleiotropic Effects

Ovariole number has a direct role in the number of eggs produced by an insect, suggesting that it is a key morphological fitness trait. Many studies have documented the variability of ovariole number and its relationship to other fitness and life-history traits in natural populations of Drosophila However, the genes contributing to this variability are largely unknown. Here, we conducted a genome-wide association study of ovariole number in a natural population of flies. Using mutations and RNAi-mediated knockdown, we confirmed the effects of 24 candidate genes on ovariole number, including a novel gene, anneboleyn (formerly CG32000), that impacts both ovariole morphology and numbers of offspring produced. We also identified pleiotropic genes between ovariole number traits and sleep and activity behavior. While few polymorphisms overlapped between sleep parameters and ovariole number, 39 candidate genes were nevertheless in common. We verified the effects of seven genes on both ovariole number and sleep: bin3, blot, CG42389, kirre, slim, VAChT, and zfh1 Linkage disequilibrium among the polymorphisms in these common genes was low, suggesting that these polymorphisms may evolve independently.

Bisphenol A interferes with swine vascular endothelial cell functions

Several studies have demonstrated that the endocrine disruptor bisphenol A (BPA) negatively affects animal and human health. An angiogenic process has been suggested among the events disrupted by this molecule, but the underlying mechanisms have not yet been clarified. The effect of BPA on angiogenesis was investigated by means of a bioassay previously validated in our laboratory. Using immortalized swine aortic endothelial cell line (AOC), the development of new blood vessels through a three-dimensional in vitro angiogenesis assay was evaluated. Subsequently, since vascular endothelial growth factor (VEGF) and nitric oxide (NO) are key players in the regulation of the angiogenic process, the effect of BPA on the production of these molecules by AOC was examined. BPA (10 μmol/L) stimulated AOC growth (p < 0.05) and VEGF production (p < 0.05), but did not modify NO levels. Our data suggest that the endocrine-disrupting effects of BPA could also be associated with the promotion of vascular growth, thus interfering with a physiologically finely tuned process resulting from a delicate balance of numerous molecular processes. The stimulatory effects of BPA on VEGF production may have negative implications, potentially switching the balance toward uncontrolled neovascularization. Moreover, since angiogenesis is involved in several pathologies, including cancer growth and progression, potential health risks of BPA exposure should be carefully monitored.

Perinatal administration of bisphenol A alters the expression of tight junction proteins in the uterus and reduces the implantation rate

We studied the effect of bisphenol-A (BPA) administration to rats, during the perinatal period, on the fertility of F1 generation and on the expression of tight junction (TJ) proteins in the uterus during early pregnancy. Pregnant Wistar dams (F0) received: BPA-L (0.05mg/kg/day), BPA-H (20mg/kg/day) or vehicle, from gestational day (GD) 6 to lactation day 21. F1 female pups were mated at 3 months of age and sacrificed at GD 1, 3, 6, and 7. Serum hormonal levels, ovulation rate, number of implantation sites and expression of TJ proteins in the uterus of F1 females were evaluated. BPA treatment induced no change in ovulation rate, but induced alterations in progesterone (P₄) and estradiol (E₂) serum levels, and in implantation rate. With regards to TJ proteins, BPA-H increased claudin-1 during all GDs; eliminated the peaks of claudins -3 and -4 at GD 3 and 6, respectively; and decreased claudin-7 at GD 6, ZO-1 from GD 1-6, and claudin-3 at GD 7 in stromal cells. BPA-L instead, eliminated claudin-3 peak at GD 3, increased claudin-4 and decreased claudin-7 from GD 1-6, decreased claudin-1 at GD 3 and 7 and claudin-4 at GD 7 in stromal cells. BPA-L also decreased ZO-1 at GDs 1 and 3 and increased ZO-1 at GD 6. Thus, BPA treatment during perinatal period perturbed, when the animals reached adulthood and became pregnant, the particular expression of TJ proteins in the uterine epithelium and reduced in consequence the number of implantation sites.

Differences in the Rate of in Situ Mammary Gland Development and Other Developmental Endpoints in Three Strains of Female Rat Commonly Used in Mammary Carcinogenesis Studies: Implications for Timing of Carcinogen Exposure

The potential of chemicals to alter susceptibility to mammary tumor formation is often assessed using a carcinogen-induced study design in various rat strains. The rate of mammary gland (MG) development must be considered so that the timing of carcinogen administration is impactful. In this study, in situ MG development was assessed in females of the Harlan Sprague-Dawley (Hsd:SD), Charles River Sprague-Dawley (Crl:SD), and Charles River Long-Evans (Crl:LE) rat strains at postnatal days 25, 33, and 45. Development was evaluated by physical assessment of growth parameters, developmental scoring, and quantitative morphometric analysis. Although body weight (BW) was consistently lower and day of vaginal opening (VO) occurred latest in female Hsd:SD rats, they exhibited accelerated pre- and peripubertal MG development compared to other strains. Glands of Crl:SD and Crl:LE rats exhibited significantly more terminal end buds (TEBs) and TEB/mm than Hsd:SD rats around the time of VO. These data suggest a considerable difference in the rate of MG development across commonly used strains, which is independent of BW and timing of VO. In mammary tumor induction studies employing these strains, administration of the carcinogen should be timed appropriately, based on strain, to specifically target the peak of TEB occurrence.

Polycystic ovary syndrome and environmental toxins

Polycystic ovary syndrome (PCOS) is the most common, heterogeneous, and multifactorial endocrine disorder in premenopausal women. The pathophysiology of this endocrinopathy is still unclear; however, the heterogeneity of its features within ethnic races, geographic location, and families suggests that environment and lifestyle are of prime importance. This work is mainly focused on the possible role of the most common and studied environmental toxins for this syndrome in the pathogenesis of PCOS. Plasticizers, such as bisphenol A (BPA) or phthalates, which belong to the categories of endocrine disrupting chemicals (EDCs) and advanced glycation end products (AGEs), affect humans' health in everyday, industrialized life; therefore special attention should be paid to such exposure. Timing of exposure to EDCs is crucial for the intensity of adverse health effects. It is now evident that fetuses, infants, and/or young children are the most susceptible groups, especially in the early development periods. Prenatal exposure to EDCs that mimic endogenous hormones may contribute to the altered fetal programming and in consequence lead to PCOS and other adverse health effects, potentially transgenerationally. Acute or prolonged exposure to EDCs and AGEs through different life cycle stages may result in destabilization of the hormonal homeostasis and lead to disruption of reproductive functions. They may also interfere with metabolic alterations such as obesity, insulin resistance, and compensatory hyperinsulinemia that can exacerbate the PCOS phenotype and contribute to PCOS consequences such as type 2 diabetes and cardiovascular disease. Since wide exposure to environmental toxins and their role in the pathophysiology of PCOS are supported by extensive data derived from diverse scientific models, protective strategies and strong recommendations should be considered to reduce human exposure to protect present and future generations from their adverse health effects.

Minireview: Endocrine Disruptors: Past Lessons and Future Directions

Within the past few decades, the concept of endocrine-disrupting chemicals (EDCs) has risen from a position of total obscurity to become a focus of dialogue, debate, and concern among scientists, physicians, regulators, and the public. The emergence and development of this field of study has not always followed a smooth path, and researchers continue to wrestle with questions about the low-dose effects and nonmonotonic dose responses seen with EDCs, their biological mechanisms of action, the true pervasiveness of these chemicals in our environment and in our bodies, and the extent of their effects on human and wildlife health. This review chronicles the development of the unique, multidisciplinary field of endocrine disruption, highlighting what we have learned about the threat of EDCs and lessons that could be relevant to other fields. It also offers perspectives on the future of the field and opportunities to better protect human health.

A dynamic simulation of bisphenol A dosimetry in neuroendocrine organs

Bisphenol A (BPA) is a known xenoestrogen with similar properties to 17b-estradiol. BPA and estrogen are hydrophobic compounds, and this affects the pharmacokinetics of both compounds in mammals. In a previous study we measured the distribution of BPA in female F344 rats exposed to oral doses of 0.1, 10 and 100 mg/kg. The results showed distribution to target neuroendocrine organs at all doses tested. Using these results, we developed a pharmacokinetic model to predict the dynamic uptake and excretion of BPA by various routes of exposure (po, iv, sc, ip). The model was able to simulate the entire time course (48 h) following various routes of exposure in rats over the dose ranges tested. The model indicated that the ultimate tissue uptake of BPA was established by the rapid initial transfer of free BPA into tissues. After free BPA enters the systemic circulation, metabolism and excretion reactions cause a relatively short duration and rapid decline. This period is followed by a slower long-term decline characteristic of BPA’s biphasic pharmacokinetics. Plasma protein and tissue binding reactions established the long-term half-life of BPA in the body. Route differences in tissue uptake were directly related to the competition between transfer and binding reactions during the absorption phase.

Endocrine disrupting chemical, bisphenol-A, induces breast cancer associated gene HOXB9 expression in vitro and in vivo

HOXB9 is a homeobox-containing gene that plays a key role in mammary gland development and is associated with breast and other types of cancer. Here, we demonstrate that HOXB9 expression is transcriptionally regulated by estradiol (E2), in vitro and in vivo. We also demonstrate that the endocrine disrupting chemical bisphenol-A (BPA) induces HOXB9 expression in cultured human breast cancer cells (MCF7) as well as in vivo in the mammary glands of ovariectomized (OVX) rats. Luciferase assay showed that estrogen-response-elements (EREs) in the HOXB9 promoter are required for BPA-induced expression. Estrogen-receptors (ERs) and ER-co-regulators such as MLL-histone methylase (MLL3), histone acetylases, CBP/P300, bind to the HOXB9 promoter EREs in the presence of BPA, modify chromatin (histone methylation and acetylation) and lead to gene activation. In summary, our results demonstrate that BPA exposure, like estradiol, increases HOXB9 expression in breast cells both in vitro and in vivo through a mechanism that involves increased recruitment of transcription and chromatin modification factors.

A Review of the Clinical Implications of Breast Cancer Biology

BACKGROUND

Histologically similar tumors may have different prognoses and responses to treatment. These differences are due to molecular differences. Hence, in this review, the biological interaction of breast cancer in several different areas is discussed. In addition, the performance and clinical application of the most widely-recognized biomarkers, metastasis, and recurrences from a biological perspective and current global advances in these areas are addressed.

OBJECTIVE

This review provides the performance and clinical application of the most widely-recognized biomarkers, metastasis, and recurrences from the biological perspective and current global advances in these areas.

METHODS

PubMed, Scopus, and Google Scholar were searched comprehensively with combinations of the following keywords: "breast cancer," "biological markers," and "clinical." The definition of breast cancer, diagnostic methods, biological markers, and available treatment approaches were extracted from the literature.

RESULTS

Estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER-2), and Ki-67 are the most well-known biological markers that have important roles in prognosis and response to therapeutic methods. Some studies showed the response of ER-positive and PR-negative tumors to anti-estrogenic treatment to be lower than ER-positive and PR-positive tumors. Patients with high expression of HER-2 and Ki-67 had a poor prognosis. In addition, recent investigations indicated the roles of new biomarkers, such as VEGF, IGF, P53 and P21, which are associated with many factors, such as age, race, and histological features.

CONCLUSION

The objective of scientists, from establishing a relationship between cancer biology infrastructures with clinical manifestations, is to find new ways of prevention and progression inhibition and then possible introduction of less dangerous and better treatments to resolve this dilemma of human society.