Evidence of the Possible Harm of Endocrine-Disrupting Chemicals in Humans: Ongoing Debates and Key Issues

Thyroid under siege: Unravelling the toxic impact of real-life metal mixture exposures in Wistar rats

This study explored the effect of a toxic metal(oid) mixture (cadmium, lead, arsenic, mercury, chromium, and nickel) on thyroid function in Wistar rats exposed for 28 or 90 days. Dose levels were determined based on prior human-biomonitoring investigation. The experiment included control (male/female rats, 28 and 90 days) and treated groups, reflecting the lower confidence limit of the Benchmark Dose (BMDL) for hormone levels (M1/F1, 28 and 90 days), median concentrations (M2/F2, 28 and 90 days), 95th percentile concentrations (M3/F3, 28 and 90 days) measured in a human study, and reference values for individual metals extracted from the literature (M4/F4, 28 days only). Blood and thyroid gland samples were collected at the experimental termination. Serum TSH, fT3, fT4, T3, and T4 levels were measured, and SPINA-GT and SPINA-GD parameters were calculated. In silico analysis, employing the Comparative Toxicogenomic Database and ToppGene Suite portal, aimed to reveal molecular mechanisms underlying the observed effects. Results showed greater sensitivity in the female rats, with significant effects observed at lower doses. Subacute exposure increased TSH, fT3, and T3 levels in females, while subchronic exposure in males decreased TSH and fT3 levels and increased fT4. Subacute exposure induced changes even at allegedly safe doses, emphasizing potential health risks. Histological abnormalities were observed in all the treated groups. In silico findings suggested that toxic metal exposure contributes to thyroid disorders via oxidative stress, disruption of micronutrients, interference with hormone synthesis, and gene expression dysregulation. These results indicate that seemingly safe doses in single-substance research can adversely affect thyroid structure and function when administered as a mixture. These findings highlight the complex impact of toxic metal exposure on thyroid health, emphasizing that adhering to accepted safety limits for single-substance research fails to account for adverse effects on thyroid structure and function upon exposures to metal mixtures.

Joint and interactive effects of metal mixtures on liver damage: Epidemiological evidence from repeated-measures study

BACKGROUND

The impact of heavy metals on liver function has been examined in numerous epidemiological studies. However, these findings lack consistency and longitudinal validation.

METHODS

In this study, we conducted three follow-up surveys with 426 participants from Northeast China. Blood and urine samples were collected, along with questionnaire information. Urine samples were analyzed for concentrations of four metals (chromium [Cr], cadmium [Cd], lead [Pb], and manganese [Mn]), while blood samples were used to measure five liver function indicators (alanine aminotransferase [ALT], aspartate aminotransferase [AST], albumin [ALB], globulin [GLB], and total protein [TP]). We utilized a linear mixed-effects model (LME) to explore the association between individual heavy metal exposure and liver function. Joint effects of metal mixtures were investigated using quantile g-computation and Bayesian kernel machine regression (BKMR). Furthermore, we employed BKMR and Marginal Effect models to examine the interaction effects between metals on liver function.

RESULTS

The LME results demonstrated a significant association between urinary heavy metals (Cr, Cd, Pb, and Mn) and liver function markers. BKMR results indicated positive associations between heavy metal mixtures and ALT, AST, and GLB, and negative associations with ALB and TP, which were consistent with the g-comp results. Synergistic effects were observed between Cd-Cr on ALT, Mn-Cr and Cr-Pb on ALB, while an antagonistic effect was found between Mn-Pb and Mn-Cd on ALB. Additionally, synergistic effects were observed between Mn-Cr on GLB and Cd-Cr on TP. Furthermore, a three-way antagonistic effect of Mn-Pb-Cr on ALB was identified.

CONCLUSION

Exposure to heavy metals (Cr, Cd, Mn, Pb) is associated with liver function markers, potentially leading to liver damage. Moreover, there are joint and interaction effects among these metals, which warrant further investigation at both the population and mechanistic levels.

Cadmium exposure and thyroid hormone disruption: a systematic review and meta-analysis

INTRODUCTION

This meta-analysis aimed to analyze the effect of cadmium (Cd) exposure on thyroid hormone disruption.

CONTENT

Databases including PubMed, Embase, Cochrane Library, and Scopus were searched for studies published up to December 14, 2022. Studies evaluating the association between Cd exposure (blood Cd [BCd] or urine Cd [UCd]) and thyroid function (thyroid-stimulating hormone [TSH], free thyroxine [FT4], total triiodothyronine [TT3]) or thyroid autoimmunity (thyroglobulin antibody [TgAb] or thyroperoxidase Ab [TPOAb]) were included.

SUMMARY AND OUTLOOK

This systematic review included 12 cross-sectional studies. Cd exposure showed a neutral association with TSH (pooled correlation=0.016, 95 % confidence interval [CI]=-0.013 to 0.045, p=0.277), FT4 (pooled correlation=0.028, 95 % CI=-0.005 to 0.061, p=0.098), and thyroid autoimmunity (pooled odds ratio=1.143, 95 % CI=0.820-1.591, p=0.430). However, Cd exposure showed a positive association with TT3 (pooled correlation=0.065, 95 % CI=0.050-0.080, p<0.001), which was consistent with the BCd and UCd subgroup analyses (pooled correlation=0.053 and 0.081, respectively, both p<0.001). Cd exposure was not associated with TSH, FT4, or thyroid autoimmunity but tended to increase with TT3.

Human health risk assessment for consumption of microplastics and plasticizing substances through marine species

A special characteristic of MP (microplastics) in the ocean is they may act as carriers of additives specific to the plastic materials used in their manufacture, such as plasticizers, among which Bisphenol-A (BPA), bis (2-ethylhexyl) phthalate (DEHP), dybuthyl phthalate (DBP). Both MP as the plasticizers were searched in composite samples of mangrove cockle (Anadara tuberculosa), Stolzmann's weakfish (Cynoscion stolzmanni) and arched swimming crab (Callinectes arcuatus). Extraction of MP was done through physical-chemical techniques and identification was carried out employing the techniques of light microscopy, energy dispersive spectrometer (EDS), scanning electron microscope (SEM) and Raman spectroscopy; the sizes of MP obtained were between 0.5 μm and 106 μm, the following average results being obtained: for Arched swimming crab 4.0 ± 1.0 MP/g; mangrove cockle 3.3 ± 2.9 MP/g; and for Stolzmann's weakfish, the average was 2.4 ± 1.3 MP/g; the most observed shapes were fibers and irregular segments; the most identified MP was polyethylene terephthalate (PET). Regarding extraction and quantification of plasticizers, the extraction stage was carried out using QuEChERS tubes; and the identification and quantification with gas chromatography coupled to a mass spectrometer (GC-MS). Regarding the plasticizing substances, DEHP was found in detectable levels in all the samples; BPA was found in 84% of the composite samples analyzed; DBP was found in 50% of them, of the analyzed samples 34% were positive for the 3 analytes. The dietary exposure of people to plasticizers was calculated and for BPA the exposure obtained was compared with respect to the TDI (tolerable intake dose) for pregnant women and the new TDI proposed by EFSA in 2021 according to the estrogenic effect of this substance in the fetus. The objective of the work was to determine if a relationship could be established between both PM and plasticizers, which gave a positive relationship.

Effects of postnatal exposure to phthalate, bisphenol a, triclosan, parabens, and per- and poly-fluoroalkyl substances on maternal postpartum depression and infant neurodevelopment: a korean mother-infant pair cohort study

Exposure to endocrine-disrupting chemicals (EDCs) can promote infant neurodevelopmental impairment and maternal postpartum depression (PPD). However, the associations between lactation exposure to EDCs, maternal PPD, and infant neurodevelopment are unclear. Hence, we investigated these relationships in infants aged 36-42 months. We recruited 221 Korean mothers and analyzed 29 EDCs. The Edinburgh Postnatal Depression Scale (EPDS) was used to assess maternal PPD. Bayley scales of infant development; the Swanson, Nolan, and Pelham rating scale (SNAP); and the Child Behavior Checklist (CBCL) were used to assess neurodevelopment in infants exposed to the top 30% of EDC over three years. Multiple regression analyses were adjusted for maternal age, pre-pregnancy body mass index, education, income, employment, residence, and infant age and sex. The rates of infants with clinically abnormal diagnoses on neurologic developmental tests (Balyey, SNAP, and CBCL scales) ranged from 7.7 to 38.5% in this study, with the motor and hyperactivity/impulsivity areas scoring the highest among 65 boys and girls. Mono-2-ethylhexyl phthalate (MEHP) and mono-isononyl phthalate (MiNP) levels in breast milk significantly correlated with infant inattention and hyperactivity. Perfluorononanoic acid (PFNA) and perfluorooctyl sulfonate (PFOS) levels correlated significantly with motor development of BSID-III and total CBCL score which mean infant might have lower developmental status. EDC concentrations in breast milk were not associated with maternal PPD. Overall, lactational exposure to EDCs during the postpartum period can exert a negative effect on maternal PPD and infant neurodevelopment.

Reconsidering "low-dose"-Impacts of oral estrogen exposure during preimplantation embryo development

Perturbations of estrogen signaling during developmental stages of high plasticity may lead to adverse effects later in life. Endocrine-disrupting chemicals (EDC) are compounds that interfere with the endocrine system by particularly mimicking the action of endogenous estrogens as functional agonists or antagonists. EDCs compose synthetic and naturally occurring compounds discharged into the environment, which may be taken up via skin contact, inhalation, orally due to contaminated food or water, or via the placenta during in utero development. Although estrogens are efficiently metabolized by the liver, the role of circulating glucuro- and/or sulpho-conjugated estrogen metabolites in the body has not been fully addressed to date. Particularly, the role of intracellular cleavage to free functional estrogens could explain the hitherto unknown mode of action of adverse effects of EDC at very low concentrations currently considered safe. We summarize and discuss findings on estrogenic EDC with a focus on early embryonic development to highlight the need for reconsidering low dose effects of EDC.

The risks of marine micro/nano-plastics on seafood safety and human health

A considerable mass of plastics has been released into the marine environment annually through different human activities, including industrial, agriculture, medical, pharmaceutical and daily care products. These materials are decomposed into smaller particles such as microplastic (MP) and nanoplastic (NP). Hence, these particles can be transported and distributed in coastal and aquatic areas and are ingested by the majority of marine biotas, including seafood products, thus causing the contamination of the different parts of aquatic ecosystems. In fact, seafood involves a wide diversity of edible marine organisms, such as fish, crustaceans, molluscs, and echinoderms, which can ingest the micro/nanoplastics particles, and then transmit them to humans through dietary consumption. Consequently, these pollutants can cause several toxic and adverse impacts on human health and the marine ecosystem. Therefore, this chapter provides information on the potential risks of marine micro/nanoplastics on seafood safety and human health.

Human adrenocortical carcinoma cell line (NCI-H295R): An in vitro screening model for the assessment of endocrine disruptors' actions on steroidogenesis with an emphasis on cell ultrastructural features

Cell lines as an in vitro model for xenobiotic screening and toxicity studies provide a very important tool in the field of scientific research at the level of molecular pathways and gene expression. Good cell culture practice and intracellular characterization, as well as physiological properties of the cell line are of critical importance for in vitro reproductive toxicity testing of various endocrine-disrupting chemicals. The NCI-H295R, human adrenocarcinoma cell line, is the most widely used in vitro cellular system to study the human adrenal steroidogenic pathway at the level of hormone production and gene expression, as it expresses genes that encode for all the key enzymes for steroidogenesis. In this review, we aim to highlight the information considering the origin, development, physiological and ultrastructural characteristics of the NCI-H295R cell line. The review also creates a broad overview of the cell line usage in various range of studies related to the steroidogenesis issues. To our best knowledge, the paper provides the first report of quantitative data (ex novo) from stereological estimates of component (volume, surface) densities of nuclei, mitochondria, and lipid droplets of the NCI-H295R cells. Such ultrastructural measurements can be valuable in the assessment of underlying mechanisms of changes in the cell steroid hormone production induced by the action of diverse endocrine disruptors. Thus, they can significantly contribute to complexity of structure-function relationships in association with steroidogenesis.

UV-B Filter Octylmethoxycinnamate Is a Modulator of the Serotonin and Histamine Receptors in Human Umbilical Arteries

Every day, people use personal care products containing UV filters. Although their use initially showed a protective role, toxicity is a concern for human health as several UV filters are endocrine-disrupting chemicals (EDCs). Exposure to EDCs may induce cardiovascular diseases and can affect the health of sensitive people, such as pregnant women. Currently, the world’s most widely used UV-B filter is octylmethoxycinnamate (OMC), an EDC. However, the disruptive effects on pregnant women are little known. The present work proposed to understand how long-term exposure to OMC affects vascular homeostasis. Endothelium-denuded human umbilical artery (HUA) rings were incubated in an organ bath system. Long-term effects of exposure to OMC (0.001–50 μmol/L) were evaluated on the contractile responses of HUA to the application of the contractile agents, serotonin (5-HT) and histamine (Hist). To investigate in more detail the vascular mode of action of OMC, through which it impairs the vascular homeostasis of HUA, the activity and expression of different 5-HT and Hist-receptors involved in contractility processes were studied. Our findings pointed out an increase in the reactivity of HUA to 5-HT and Hist due to OMC exposure. These alterations in reactivity may be precursors of preeclampsia development and/or gestational hypertension.

Microbiota analysis for risk assessment: evaluation of hazardous dietary substances and its potential role on the gut microbiome variability and dysbiosis

The expansion of fields related to probiotics, microbiome‐targeted interventions and an evolving landscape for implementation across policy, industry and end users, signifies an era of important clinical translational changes. Characteristics and perception of traditional probiotics stemmed from the historical long‐term use of fermented products. Although the distinction between probiotic microorganisms and fermentation‐associated microbes is important, it is often confused as not all fermented foods are probiotic supplements. Current innovation in area of biotechnology and bioinformatics is emerging outside of the classical definitions and new probiotics will emerge from novel sources, challenging scientific as well as regulatory instructions. At the same time, the search for individual and group microbiome signatures – biomarkers in order to predict disease incidence, progression and response to treatment is a key area of microbiological and multidisciplinary research, enabled by efficient and powerful processing of large data sets. However, the regulation of marketed beneficial microbes and probiotics differs among countries and the basic level of classification, which depend on probiotic classification is not globally harmonised. At the same time, the regulation is very demanding to evaluate the safety of products on the market, so that only those products with scientific evidence benefits can obtain positive recognition in ways of health claims. Collaborative experimental and theoretical approaches and case studies have assisted the progress in this crosscutting area of research. There is a requirement to clearly specify criteria and provide details about ways and approaches of achieving those criteria with the intention that manufacturers can benefit from a transparent way of communicating product quality to end users.

Systematic review of prenatal exposure to endocrine disrupting chemicals and autism spectrum disorder in offspring

LAY ABSTRACT

Autism spectrum disorders comprise a complex group with many subtypes of behaviorally defined neurodevelopmental abnormalities in two core areas: deficits in social communication and fixated, restricted, repetitive, or stereotyped behaviors and interests each with potential unique risk factors and characteristics. The underlying mechanisms and the possible causes of autism spectrum disorder remain elusive and while increased prevalence is undoubtable, it is unclear if it is a reflection of diagnostic improvement or emerging risk factors such as endocrine disrupting chemicals. Epidemiological studies, which are used to study the relation between endocrine disrupting chemicals and autism spectrum disorder, can have inherent methodological challenges that limit the quality and strength of their findings. The objective of this work is to systematically review the treatment of these challenges and assess the quality and strength of the findings in the currently available literature. The overall quality and strength were "moderate" and "limited," respectively. Risk of bias due to the exclusion of potential confounding factors and the lack of accuracy of exposure assessment methods were the most prevalent. The omnipresence of endocrine disrupting chemicals and the biological plausibility of the association between prenatal exposure and later development of autism spectrum disorder highlight the need to carry out well-designed epidemiological studies that overcome the methodological challenges observed in the currently available literature in order to be able to inform public policy to prevent exposure to these potentially harmful chemicals and aid in the establishment of predictor variables to facilitate early diagnosis of autism spectrum disorder and improve long-term outcomes.

Elucidation of xenoestrogen metabolism by non-targeted, stable isotope-assisted mass spectrometry in breast cancer cells

Environmental exposure to xenoestrogens, i.e., chemicals that imitate the hormone 17β-estradiol, has the potential to influence hormone homeostasis and action. Detailed knowledge of xenobiotic biotransformation processes in cell models is key when transferring knowledge learned from in vitro models to in vivo relevance. This study elucidated the metabolism of two naturally-occurring phyto- and mycoestrogens; namely genistein and zearalenone, in an estrogen receptor positive breast cancer cell line (MCF-7) with the aid of stable isotope-assisted metabolomics and the bioinformatic tool MetExtract II. Metabolism was studied in a time course experiment after 2 h, 6 h and 24 h incubation. Twelve and six biotransformation products of zearalenone and genistein were detected, respectively, clearly demonstrating the abundant xenobiotic biotransformation capability of the cells. Zearalenone underwent extensive phase-I metabolism resulting in α-zearalenol (α-ZEL), a molecule known to possess a significantly higher estrogenicity, and several phase-II metabolites (sulfo- and glycoconjugates) of the native compound and the major phase I metabolite α-ZEL. Moreover, potential adducts of zearalenone with a vitamin and several hydroxylated metabolites were annotated. Genistein metabolism resulted in sulfation, combined sulfation and hydroxylation, acetylation, glucuronidation and unexpectedly adduct formation with pentose- and hexose sugars. Kinetics of metabolite formation and subsequent excretion into the extracellular medium revealed a time-dependent increase in most biotransformation products. The untargeted elucidation of biotransformation products formed during cell culture experiments enables an improved and more meaningful interpretation of toxicological assays and has the potential to identify unexpected or unknown metabolites.

Fetoplacental vasculature as a model to study human cardiovascular endocrine disruption

Increasing evidence has associated the exposure of endocrine-disrupting chemicals (EDCs) with the cardiovascular (CV) system. This exposure is particularly problematic in a sensitive window of development, pregnancy. Pregnancy exposome can affect the overall health of the pregnancy by dramatic changes in vascular physiology and endocrine activity, increasing maternal susceptibility. Moreover, fetoplacental vascular function is generally altered, increasing the risk of developing pregnancy complications (including cardiovascular diseases, CVD) and predisposing the foetus to adverse health risks later in life. Thus, our review summarizes the existing literature on exposures to EDCs during pregnancy and adverse maternal health outcomes, focusing on the human placenta, vein, and umbilical artery associated with pregnancy complications. The purpose of this review is to highlight the role of fetoplacental vasculature as a model for the study of human cardiovascular endocrine disruption. Therefore, we emphasize that the placenta, together with the umbilical arteries and veins, allows a better characterization of the pregnant woman's exposome. Consequently, it contributes to the protection of the mother and foetus against CV disorders in life.

A Review on Emerging Pollutants in the Water Environment: Existences, Health Effects and Treatment Processes

Emerging pollutants (EPs), also known as micropollutants, have been a major issue for the global population in recent years as a result of the potential threats they bring to the environment and human health. Pharmaceuticals and personal care products (PPCPs), antibiotics, and hormones that are used in great demand for health and cosmetic purposes have rapidly culminated in the emergence of environmental pollutants. EPs impact the environment in a variety of ways. EPs originate from animal or human sources, either directly discharged into waterbodies or slowly leached via soils. As a result, water quality will deteriorate, drinking water sources will be contaminated, and health issues will arise. Since drinking water treatment plants rely on water resources, the prevalence of this contamination in aquatic environments, particularly surface water, is a severe problem. The review looks into several related issues on EPs in water environment, including methods in removing EPs. Despite its benefits and downsides, the EPs treatment processes comprise several approaches such as physico-chemical, biological, and advanced oxidation processes. Nonetheless, one of the membrane-based filtration methods, ultrafiltration, is considered as one of the technologies that promises the best micropollutant removal in water. With interesting properties including a moderate operating manner and great selectivity, this treatment approach is more popular than conventional ones. This study presents a comprehensive summary of EP’s existence in the environment, its toxicological consequences on health, and potential removal and treatment strategies.

Microplastics in aquatic environment: Challenges and perspectives

The occurrence of microplastics in the aquatic environment has become a growing concern globally. Microplastics pose a hazard to the ecological system, and their presence, particularly in the water, has an adverse impact on human health and the ecosystem. Microplastics are released into the environment directly from everyday used plastic items, degradation of plastics, industries, and wastewater treatment plants. Once these contaminants enter the water, aquatic life feeds on them, and microplastics enter the food chain and cause severe health hazards. An assessment of microplastics' ecological risks is essential; however, it is challenging in the present scenario due to limited information available. To fill these knowledge gaps, this paper comprehensively reviews the sources and transport of microplastics in the water environment and their environmental and health effects, global policy frameworks, analytical techniques for microplastic detection, and control strategies to prevent microplastics release in the aquatic environment.

Impact of endocrine-disrupting chemicals on steroidogenesis and consequences on testicular function

Testicular steroidogenesis is a tightly regulated process that produces the androgens important for the development, maintenance and function of the male reproductive system. These androgens are also essential for overall health, and well-being. Disruptions in the ability of the testis to form steroids can result in developmental abnormalities, dysfunction, and infertility. Endocrine-disrupting chemicals (EDCs) can interfere with the intricate signaling and metabolizing networks that produce androgens and promote their dysfunction. These chemicals are found ubiquitously in our environment, as they are integral components of products that are used every day. The effects of EDCs, such as bisphenols, phthalates, and alkyl chemicals, have been studied independently, revealing deleterious effects; but the combined influence of these structures on steroidogenesis has yet to be completely elucidated. This manuscript presents an updated review on EDC mixtures and their impact on testicular function and fertility, highlighting new findings that illustrate the anti-androgenic capabilities of EDC mixtures.

Role of Endocrine-Disrupting Chemicals in the Pathogenesis of Non-Alcoholic Fatty Liver Disease: A Comprehensive Review

Non-alcoholic fatty liver disease (NAFLD) is considered the most common liver disorder, affecting around 25% of the population worldwide. It is a complex disease spectrum, closely linked with other conditions such as obesity, insulin resistance, type 2 diabetes mellitus, and metabolic syndrome, which may increase liver-related mortality. In light of this, numerous efforts have been carried out in recent years in order to clarify its pathogenesis and create new prevention strategies. Currently, the essential role of environmental pollutants in NAFLD development is recognized. Particularly, endocrine-disrupting chemicals (EDCs) have a notable influence. EDCs can be classified as natural (phytoestrogens, genistein, and coumestrol) or synthetic, and the latter ones can be further subdivided into industrial (dioxins, polychlorinated biphenyls, and alkylphenols), agricultural (pesticides, insecticides, herbicides, and fungicides), residential (phthalates, polybrominated biphenyls, and bisphenol A), and pharmaceutical (parabens). Several experimental models have proposed a mechanism involving this group of substances with the disruption of hepatic metabolism, which promotes NAFLD. These include an imbalance between lipid influx/efflux in the liver, mitochondrial dysfunction, liver inflammation, and epigenetic reprogramming. It can be concluded that exposure to EDCs might play a crucial role in NAFLD initiation and evolution. However, further investigations supporting these effects in humans are required.

Perfluoroalkyl Chemicals and Male Reproductive Health: Do PFOA and PFOS Increase Risk for Male Infertility?

Poly- and perfluoroalkyl substances (PFAS) are manmade synthetic chemicals which have been in existence for over 70 years. Though they are currently being phased out, their persistence in the environment is widespread. There is increasing evidence linking PFAS exposure to health effects, an issue of concern since PFAS such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) bioaccumulate in humans, with a half-life of years. Many epidemiological studies suggest that, worldwide, semen quality has decreased over the past several decades. One of the most worrying effects of PFOS and PFOA is their associations with lower testosterone levels, similar to clinical observations in infertile men. This review thus focuses on PFOS/PFOA-associated effects on male reproductive health. The sources of PFAS in drinking water are listed. The current epidemiological studies linking increased exposure to PFAS with lowered testosterone and semen quality, and evidence from rodent studies supporting their function as endocrine disruptors on the reproductive system, exhibiting non-monotonic dose responses, are noted. Finally, their mechanisms of action and possible toxic effects on the Leydig, Sertoli, and germ cells are discussed. Future research efforts must consider utilizing better human model systems for exposure, using more accurate PFAS exposure susceptibility windows, and improvements in statistical modeling of data to account for the endocrine disruptor properties of PFAS.

Diet: A Source of Endocrine Disruptors

BACKGROUND

Food is indispensable for human life and determines the health and wellbeing of the consumer. As food is the source of energy for humans, it also emerges as one of the most important sources of exposure to deleterious chemicals both natural and synthetic. The food exposed chemicals cause a number of detrimental health effects in humans, with endocrine disruption being of serious concern amongst these effects. Such chemicals disrupting the health of endocrine system are known as endocrine-disrupting chemicals (EDCs). The food exposed EDCs need to be identified and classified to effectuate a cautious consumption of food by all and especially by vulnerable groups.

AIM

The aim of the present review was to discuss food as a source of exposure to common endocrine disruptors in humans. This review presents the occurrence and levels of some of the critical endocrine disruptors exposed through frequently consumed diets.

METHODS

The major source of data was PubMed, besides other relevant publications. The focus was laid on data from the last five years, however significant earlier data was also considered.

CONCLUSION

The food as a source of endocrine disruptors to humans cannot be neglected. It is highly imperative for the consumer to recognize food as a source of EDCs and make informed choices in the consumption of food items.

Subacute exposure to lead promotes disruption in the thyroid gland function in male and female rats

Exposure to heavy metals, such as lead, is a global public health problem. Lead has a long historic relation to several adverse health conditions and was recently classified as an endocrine disruptor. The aim of this study was to investigate the effects of subacute exposure to lead on the thyroid gland function. Adult male and female Wistar rats received a lead acetate solution containing 10 or 25 mg/kg, by gavage, three times a week, for 14 days. One week later, behavioral testing showed no alterations in anxiety and motor-exploratory parameters, as evaluated by Open-Field and Plus-Maze Tests, but impairment in learning and memory was found in the male 25 mg/kg lead-treated group and in both female lead-treated groups, as evaluated by the Inhibitory Avoidance Test. After one week, serum levels of tT3 were reduced in the 25 mg/kg female group and in the 10 mg∕ kg male group. However, tT4 levels were increased in the 25 mg/kg male group and in both female treated groups. TSH levels did not change and lead serum levels were undetectable. Morphologic alterations were observed in the thyroid gland, including abnormal thyroid parenchyma follicles of different sizes, epithelial stratification and vacuolization of follicular cells, decrease in colloid eosinophilia and vascular congestion, accompanied by morphometric alterations. An increase in collagen deposition was also observed. No differences were observed in TPO activity or protein expression, H₂O₂ generation by NADPH oxidases or hepatic D1 mRNA expression. However, thyroid NIS protein expression was considerably decreased in the male and female lead-treated groups, while TSHr expression was decreased in the 25 mg/kg female lead-treated group. These findings demonstrated that subacute exposure to lead acetate disrupts thyroid gland function in both sexes, leading to morphophysiological impairment and to changes in learning and memory abilities.

Endocrine disrupting chemicals in the pathogenesis of hypospadias; developmental and toxicological perspectives

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Penis development is regulated by a tight balance of androgens and estrogens.

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EDCs that impact androgen/estrogen balance during development cause hypospadias.

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Cross-disciplinary collaborations are needed to define a mechanistic link.

Hypospadias is a defect in penile urethral closure that occurs in approximately 1/150 live male births in developed nations, making it one of the most common congenital abnormalities worldwide. Alarmingly, the frequency of hypospadias has increased rapidly over recent decades and is continuing to rise. Recent research reviewed herein suggests that the rise in hypospadias rates can be directly linked to our increasing exposure to endocrine disrupting chemicals (EDCs), especially those that affect estrogen and androgen signalling. Understanding the mechanistic links between endocrine disruptors and hypospadias requires toxicologists and developmental biologists to define exposures and biological impacts on penis development. In this review we examine recent insights from toxicological, developmental and epidemiological studies on the hormonal control of normal penis development and describe the rationale and evidence for EDC exposures that impact these pathways to cause hypospadias. Continued collaboration across these fields is imperative to understand the full impact of endocrine disrupting chemicals on the increasing rates of hypospadias.

Best Achievements in Translational and Basic Thyroidology in 2020

This review discusses articles published in 2020 that presented noteworthy achievements in translational and basic thyroidology. Previously unresolved questions about thyroid hormone receptor actions and signaling mechanisms were answered using various novel in vitro and in vivo models. Using high resolution cryo-electron microscopy, the fine functional structure of thyroglobulin was demonstrated, and new insights into the pathogenesis of thyroid disease were achieved, with a focus on research into thyroid-disrupting chemicals and the gut microbiome. Novel therapeutic approaches were tried in the field of advanced thyroid cancer treatments.

Plasticenta: First evidence of microplastics in human placenta

Microplastics are particles smaller than five millimeters deriving from the degradation of plastic objects present in the environment. Microplastics can move from the environment to living organisms, including mammals. In this study, six human placentas, collected from consenting women with physiological pregnancies, were analyzed by Raman Microspectroscopy to evaluate the presence of microplastics. In total, 12 microplastic fragments (ranging from 5 to 10 μm in size), with spheric or irregular shape were found in 4 placentas (5 in the fetal side, 4 in the maternal side and 3 in the chorioamniotic membranes); all microplastics particles were characterized in terms of morphology and chemical composition. All of them were pigmented; three were identified as stained polypropylene a thermoplastic polymer, while for the other nine it was possible to identify only the pigments, which were all used for man-made coatings, paints, adhesives, plasters, finger paints, polymers and cosmetics and personal care products.

The sex-specific effects of blood lead, mercury, and cadmium levels on hepatic steatosis and fibrosis: Korean nationwide cross-sectional study

AIM

The potential effects of heavy metals on non-alcoholic fatty liver disease (NAFLD) remain unknown. We investigated the sex-specific relationships of blood lead (BPb), mercury (BHg), and cadmium (BCd) levels with hepatic steatosis (HS) and fibrosis (HF).

METHOD

We included 4420 participants from the 2016-2017 Korea National Health and Nutrition Examination Survey. High-risk alcoholics and patients with chronic hepatitis B or C infections or liver cirrhosis were excluded. We calculated the hepatic steatosis index (HSI) and fibrosis-4 index (FIB-4) values; we defined the presence of HS and HF as an HSI ≥ 36 and FIB-4 score >2.67, respectively. We adjusted for age, smoking and alcohol consumption statuses, hypertension, obesity, diabetes, hypertriglyceridemia, and BPb, BHg, and BCd levels.

RESULT

In males (n = 1860), the HSI was correlated negatively with the BPb level and positively with the BHg level (both p < 0.01). The FIB-4 score was correlated positively with the BPb and BCd levels (both p < 0.01). In females (n = 2560), the HSI and FIB-4 score were correlated positively with the BPb, BHg, and BCd levels (all p < 0.01). After adjustments, the BHg level increased the risk of HS in both males (OR = 1.065, p = 0.003) and females (OR = 1.061, p = 0.048), and the BCd level increased the risk of HF in females (OR = 1.668, p = 0.012).

CONCLUSION

Blood heavy metal levels were generally correlated positively with the HSI and FIB4 score, more so in females than males. The BHg level was associated with HS in males and females, and the BCd level was associated with HF in females. Further studies on NAFLD progression according to heavy metal status and sex are warranted.

Aryl-hydrocarbon receptor binding and the incidence of type 2 diabetes: the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

BACKGROUND

Persistent organic pollutants (POPs) may cause diabetes, in part through aryl hydrocarbon receptor (AhR) binding. Ensuing mitochondrial dysfunction is postulated to mediate this effect. We aim to investigate the association of POPs with incident diabetes indirectly by bio-assaying AhR ligand bioactivity and intracellular ATP level induced by participant serum samples.

METHODS

In incident case-cohort analyses of one ELSA-Brasil center, 1605 eligible subjects without diabetes at baseline had incident diabetes ascertained by self-report, medication use, OGTT or HbA1c at follow-up 4 years later. We assayed AhR ligand bioactivity (AhRL) and intracellular ATP content, the latter reflecting the presence of mitochondria-inhibiting substances (MIS), following incubation of recombinant mouse Hepa1c1c7 cells with participant sera for 71 incident diabetes cases and 472 randomly selected controls.

RESULTS

In multiply-adjusted proportional hazards regression analyses, those with above-median AhRL and below-median MIS-ATP had 69 and 226% greater risk of developing diabetes (HR = 1.69; 95%CI 1.01-2.83 and 3.26; 1.84-5.78), respectively. A strong interaction was seen between the two exposures (HR_{high AhRL/low MIS-ATP vs. low AhRL/high MIS-ATP} = 8.15; 2.86-23.2).

CONCLUSION

The markedly increased incidence of diabetes seen in those with both higher AhR ligand bioactivity and increased mitochondrial inhibition supports the hypothesis that widespread POPs exposure contributes to the diabetes epidemic.

Detoxification Enhanced Lifestyle Intervention Targeting Endotoxemia (DELITE) in the Setting of Obesity and Pain: Results of a Pilot Group Intervention

BACKGROUND

Obesity is a complex multifactorial disorder affecting a growing proportion of the population. While therapeutic lifestyle change (TLC) is foundational, results of interventional programs are often inconsistent. Factors related to systemic inflammation, toxin load and endotoxemia have been postulated to play a contributory role. This pilot study sought to evaluate the role of TLC with enhanced laboratory evaluation and interventions to address these emerging therapeutic targets.

METHODS

Twelve participants with a body mass index (BMI) greater than 30 (or 27 with metabolic co-morbidities) were recruited from an outpatient clinic for participation with a primary outcome of pre/post changes in body composition. Participants completed a 12-week program involving weekly group and individualized dietary, exercise, and behavioral support, supplemented with a commercial, 30-day dietary detoxification intervention and ongoing nutritional counseling. All participants completed baseline and post-intervention evaluation including metabolic, toxin load, endotoxin, body composition and functional fitness profiles.

RESULTS

After 12-weeks, participants as a group significantly improved body composition parameters including BMI, body fat, fat mass, and waist and hip circumference (P < .01). Significant improvement in several secondary outcomes including levels of lipopolysaccharide, zonulin and leptin were noted. Additionally, results demonstrate substantial improvements in pain, pain interference and functional fitness. Upon completion, all participants rated the program favorably with a high likelihood of continuing or recommending participation to others.

CONCLUSIONS

Obesity remains a challenging and often refractory clinical scenario with emerging evidence indicating the potential role of systemic inflammation, toxin load and endotoxemia. A group therapeutic lifestyle change program enhanced with a detoxification component is feasible and may provide a promising intervention for achieving weight loss while also addressing functional and pain related co-morbidities. Future randomized trials evaluating the components of such a program are needed to better delineate the role of specific interventions in the complex setting of obesity.

Assessment of the endocrine disrupting properties of Bisphenol AF according to the EU criteria and ECHA/EFSA guidance

Endocrine disruptors (EDs) are exogenous compounds that interfere with the hormone system, affecting human health and environment. Specific legislative obligations have been introduced in the European Union (EU) to gradually eliminate EDs in water, industrial chemicals and pesticides. However, identification of EDs is the first and essential step towards regulation and appropriate risk management. Scientific criteria and guidance for ED assessment have recently been established for pesticides in the EU. In this project, the ED properties of the non‐pesticide chemical Bisphenol AF (BPAF), analogue and potential substitute of Bisphenol A were evaluated by the application of the EU criteria and guidance in the frame of human health risk assessment. A data dossier was built by a systematic literature review (WOS, Scopus, Pubmed, Embase), title/abstract screening (RAYYAN) and full‐text examination. All relevant information was extracted and systematically reported, and reliability and relevance of data were assessed (SciRAP). Data were synthesised into lines of evidence for (i) endocrine activity, (ii) adversity and (iii) general toxicity, and weight of evidence evaluation was applied. The initial analysis of the evidence showed potential endocrine adverse effects and endocrine activity, meeting the ED criteria and leading the assessment to the mode of action (MoA) analysis. The biological plausibility of the link between the adverse effects and the endocrine activity was investigated based on current scientific knowledge. Empirical support for dose–response and temporal concordance was evaluated, and the key events were assessed in terms of essentiality, consistency, analogy and specificity. Finally, an overall conclusion of the ED properties of BPAF was drawn. The EU criteria and guidance for EDs assessment were successfully applied to BPAF demonstrating its endocrine activity and adversity based on weight of evidence methodology and MoA analysis. The Fellow greatly increased her knowledge and hands‐on experience on ED assessment in the EU regulatory context contributing to implement transparency and structure in health risk assessment.

Developmental instability is associated with estrogenic endocrine disruption in the Chilean native fish species, Trichomycterus areolatus

Endocrine disrupting compounds (EDCs) are widespread contaminants that alter the normal functioning of the endocrine system. While they cause dysfunctions in essential biological processes, it is unclear whether EDCs also impact developmental stability. In the present study, we investigated the occurrence of estrogenic endocrine disrupting compounds in a small watershed of south-central Chile impacted by anthropogenic activities. Then, we assessed their relationship with internal levels of estrogenic active compounds and fluctuating asymmetry (FA), a proxy of developmental stability in organisms with bilateral symmetry, in a native fish species (Trichomycterus areolatus). Yeast estrogenic screen assays were performed to measure estrogenic activity in river sediments and in male fish tissues collected from 17 sites along the Chillán watershed, and geometric morphometrics used to estimate fluctuating asymmetry based on the shapes of 248 fish skulls. Estrogenic activity was detected both in sediments and male fish tissues at concentrations of up to 1005 ng and 83 ng 17β-estradiol equivalent/kg dw, respectively. No significant correlation was found between the two. However, fish tissue estrogenicity, water temperature and dissolved oxygen explained >80% of the FA population variation. By showing a significant relationship between estrogenic activity and FA of T. areolatus, our results indicate that developmental stability can be altered by estrogenic endocrine disruption, and that FA can be a useful indicator of sub-lethal stress in T. areolatus populations.

Urban-level environmental factors related to pediatric asthma

During the 20th century, urbanization has increasing and represented a major demographic and environmental change in developed countries. This ever-changing urban environment has an impact on disease patterns and prevalence, namely on noncommunicable diseases, such as asthma and allergy, and poses many challenges to understand the relationship between the changing urban environment and the children health. The complex interaction between human beings and urbanization is dependent not only on individual determinants such as sex, age, social or economic resources, and lifestyles and behaviors, but also on environment, including air pollution, indoors and outdoors, land use, biodiversity, and handiness of green areas. Therefore, the assessment and identification of the impact of urban environment on children's health have become a priority and many recent studies have been conducted with the goal of better understanding the impacts related to urbanization, characterizing indoor air exposure, identifying types of neighborhoods, or characteristics of neighborhoods that promote health benefits. Thus, this review focuses on the role of urban environmental factors on pediatric asthma.

Mechanisms of Testicular Disruption from Exposure to Bisphenol A and Phtalates

Great attention has been paid in recent years to the harmful effects of various chemicals that interfere with our natural hormone balance, collectively known as endocrine-disrupting chemicals (EDCs) or endocrine disruptors. The effects on the reproductive system of bisphenol A (BPA) and phthalates have received particular attention: while they have a short half-life, they are so widespread that human exposure can be considered as continuous. Evidence is often limited to the animal model, disregarding the likelihood of human exposure to a mixture of contaminants. Data from animal models show that maternal exposure probably has harmful effects on the male fetus, with an increased risk of urogenital developmental abnormalities. After birth, exposure is associated with changes in the hypothalamic-pituitary-testicular axis, hindering the development and function of the male genital pathways through the mediation of inflammatory mechanisms and oxidative stress. The epidemiological and clinical evidence, while generally confirming the association between reproductive abnormalities and some phthalate esters and BPA, is more contradictory, with wildly different findings. The aim of this review is therefore to provide an update of the potential mechanisms of the damage caused by BPA and phthalates to reproductive function and a review of the clinical evidence currently available in the literature.

Removal of Pharmaceutical Contaminants in Wastewater Using Nanomaterials: A Comprehensive Review

BACKGROUND

The limitless presence of pharmaceutical contaminants in discharged wastewater has emerged as a threat to aquatic species and humans. Their presence in drinking water has although raised substantial concerns, very little is known about the fate and ecological impacts of these pollutants. As a result, these pollutants are inevitably introduced to our food chain at trace concentrations. Unfortunately, the conventional wastewater treatment techniques are unable to treat pharmaceuticals completely with practical limitations. The focus has now been shifted towards nanotechnology for the successful remediation of these persistent pollutants. Thus, the current review specifically focuses on providing readers brief yet sharp insights into applications of various nanomaterials for the removal of pharmaceutical contaminants.

METHODS

An exhaustive collection of bibliographic database was done with articles having high impact and citations in relevant research domains. An in-depth analysis of screened papers was done through standard tools. Studies were categorized according to the use of nanoscale materials as nano-adsorbents (graphene, carbon nanotubes), nanophotocatalysts (metal, metal oxide), nano-filtration, and ozonation for promising alternative technologies for the efficient removal of recalcitrant contaminants.

RESULTS

A total of 365 research articles were selected. The contemporary advancements in the field of nanomaterials for drinking and wastewater treatment have been thoroughly analyzed along with their future perspectives.

CONCLUSION

The recommendations provided in this article will be useful to adopt novel strategies for on-site removal of the emerging contaminants in pharmaceutical effluents and related industries.

Transgenerational effects of BPA on female reproduction

Bisphenol A (BPA) is an abundant environmental contaminant and studies have shown the presence of BPA in the urine of over 90% of population tested in Canada and USA. In addition to its reported harmful effects, there is concern for its transgenerational effects. For a compound to induce transgenerational effect, an epigenetic mark should be mitotically and meiotically stable without reprogramming in primordial germ cells and post fertilization embryos. In the present study, female zebrafish were treated with an environmental dose (20 μg/L) of BPA and then crossed with untreated males. To assess epigenetic effects, transcript levels of several genes involved in female reproduction were measured in adult and in 24 hpf embryos up to F3 generation. Exposure to BPA affected adult female fertility up to F2 generation. In F0, F1 and F2 ovaries transcript levels for several genes involved in reproduction, including esr, star, lhcgr and fshr were affected. To investigate epigenetic mechanisms of gene expression modulation, we studied promoter DNA methylation. Among genes involved in gonadal differentiation, amh transcript level was reduced in 24 hpf embryos, up to the F3 generation. Variation in amh transcript level was associated with hyper-methylation of its promoter and changes in H3K4me3/H3K27me3 enrichment, coherent with gene silencing. The findings provide evidence for transgenerational effects of BPA in zebrafish and demonstrate that amh is susceptible to stable epigenetic alterations. CAPSULE: Transgenerational effects of BPA on female reproductive physiology.

Determining the endocrine disruption potential of industrial chemicals using an integrative approach: Public databases, in vitro exposure, and modeling receptor interactions

Environmental and occupational exposure to industrial chemicals has been linked to toxic and carcinogenic effects in animal models and human studies. However, current toxicology testing does not thoroughly explore the endocrine disrupting effects of industrial chemicals, which may have low dose effects not predicted when determining the limit of toxicity. The objective of this study was to evaluate the endocrine disrupting potential of a broad range of chemicals used in the petrochemical sector. Therefore, 139 chemicals were classified for reproductive toxicity based on the United Nations Globally Harmonized System for hazard classification. These chemicals were evaluated in PubMed for reported endocrine disrupting activity, and their endocrine disrupting potential was estimated by identifying chemicals with active nuclear receptor endpoints publicly available databases. Evaluation of ToxCast data suggested that these chemicals preferentially alter the activity of the estrogen receptor (ER). Four chemicals were prioritized for in vitro testing using the ER-positive, immortalized human uterine Ishikawa cell line and a range of concentrations below the reported limit of toxicity in humans. We found that 2,6-di-tert-butyl-p-cresol (BHT) and diethanolamine (DEA) repressed the basal expression of estrogen-responsive genes PGR, NPPC, and GREB1 in Ishikawa cells, while tetrachloroethylene (PCE) and 2,2'-methyliminodiethanol (MDEA) induced the expression of these genes. Furthermore, low-dose combinations of PCE and MDEA produced additive effects. All four chemicals interfered with estradiol-mediated induction of PGR, NPPC, and GREB1. Molecular docking demonstrated that these chemicals could bind to the ligand binding site of ERα, suggesting the potential for direct stimulatory or inhibitory effects. We found that these chemicals altered rates of proliferation and regulated the expression of cell proliferation associated genes. These findings demonstrate previously unappreciated endocrine disrupting effects and underscore the importance of testing the endocrine disrupting potential of chemicals in the future to better understand their potential to impact public health.

Adverse Effect of Nonylphenol on the Reproductive System in F2 Male Mice : A Qualitative Change?

Previously, we reported negative effects of low-dose nonylphenol (NP) exposure on the reproductive organs of F1 male mice. In the present study was further investigated the endocrine disrupting effect of NP exposure to F2 generation male mice. Mice were divided into 2 groups; (1) CON, control animals and (2) NP-50 (50 μg/L), animals were treated with NP via drinking water. NP exposures were continuously conducted from parental pre-mating period until the postnatal day (PND) 55 of F2 offsprings. Mice were sacrificed on PND 55 and the reproductive tissue weights were measured. The initial (at PND 21) and terminal (PND 55) body weights of the NP-50 group animals were not significantly different from those of control group animals. NP exposure fail to induce a significant weight change of the testes, seminal vesicle and prostate except absolute epididymal weight (p<0.05). However, pathohistological studies revealed that NP-treated F2 animals showed evident decrease in seminiferous tubule diameters, reduced luminal area and number of germ cells. Also, sloughing morphologies in the tubules were notable. In the caudal epididymis, fewer mature sperms and swollen epithelial cells were found in the NP-treated group. The present study demonstrated that the subchronic low-dose NP exposure induced pathohistological abnormalities in testis and epididymis of F2 mice, and we assumed that these ‘qualitative’ changes in reproductive tissues could be derived from the epigenetic modifications such as DNA methylation, histone modification, altered DNA accessibility and chromatin structure. Further studies are needed to achieve a better understanding on the multi- or trans-generational effects of NP on the reproductive health and a human application.

Exposure to polybrominated biphenyl and stochastic epigenetic mutations: application of a novel epigenetic approach to environmental exposure in the Michigan polybrominated biphenyl registry

Endocrine-disrupting compounds are associated with altered epigenetic regulation and adverse health outcomes, although inconsistent results suggest that people have varied responses to the same exposure. Interpersonal variation in response to environmental exposures is not identified using standard, population-based methods. However, methods that capture an individual's response, such as analyzing stochastic epigenetic mutations (SEMs), may capture currently missed effects of environmental exposure. To test whether polybrominated biphenyl (PBB) was associated with SEMs, DNA methylation was measured using Illumina's MethylationEPIC array in PBB-exposed individuals, and SEMs were identified. Association was tested using a linear regression with robust sandwich variance estimators, controlling for age, sex, lipids, and cell types. The number of SEMs was variable (range: 119-18,309), and positively associated with age (p = 1.23e-17), but not with sex (p = 0.97). PBBs and SEMs were only positively associated in people who were older when they were exposed (p = 0.02 vs. p = 0.91). Many subjects had SEMs enriched in biological pathways, particularly in pathways involved with xenobiotic metabolism and endocrine function. Higher number of SEMs was also associated with higher age acceleration (intrinsic: p = 1.70e-3; extrinsic: p = 3.59e-11), indicating that SEMs may be associated with age-related health problems. Finding an association between environmental contaminants and higher SEMs may provide insight into individual differences in response to environmental contaminants, as well as into the biological mechanism behind SEM formation. Furthermore, these results suggest that people may be particularly vulnerable to epigenetic dysregulation from environmental exposures as they age.

4-Nonylphenol-enhanced EZH2 and RNF2 expression, H3K27me3 and H2AK119ub1 marks resulting in silencing of p21CDKN1A in vitro

Aim: To examine the impact of 4-nonylphenol (4-NP), on the expression of polycomb repressive complexes and cellular proliferation. Materials & methods: Cell proliferation assays, quantitative PCR, Western blotting, luciferase reporter assay, chromatin immunoprecipitation-quantitative PCR were used for the study. Results: The 4-NP at 100 nM concentration significantly increased proliferation of MCF-7 cells. It enhanced the expression of RNF2-BMI1 and EZH2-SUZ12 and concomitantly increased H2AK119ub1 and H3K27me3 repressive marks at p21 proximal promoter resulting in its reduced expression. Selective inhibition of RNF2 or EZH2 reverted the 4-NP action. The phospho-CREB, SP1 and E2F-1 are enriched at proximal promoter of RNF2 and EZH2 and cyclin D1, but not p21. Conclusion: The 4-NP-mediated upregulation of RNF2 and EZH2 resulted in epigenetic silencing of p21.

Association of serum levels of p,p'- Dichlorodiphenyldichloroethylene (DDE) with type 2 diabetes in African American and Caucasian adult men from agricultural (Delta) and non-agricultural (non-Delta) regions of Mississippi

Epidemiological associations were reported in several studies between persistent organochlorine organic pollutants and type 2 diabetes mellitus (T2D). Mississippi is a highly agricultural state in the USA, particularly the Delta region, with previous high usage of organochlorine (OC) insecticides such as p,p'- dichlorodiphenyltrichloroethane (DDT). In addition, there is a high proportion of African Americans who display elevated prevalence of T2D. Therefore, this State provides an important dataset for further investigating any relationship between OC compounds and metabolic diseases. The aim of this study was to assess whether soil and serum levels of OC compounds, such as p,p'- dichlorodiphenyldichloroethylene (DDE), arising from the heavy historical use of legacy OC insecticides, might serve as an environmental public health indicator for T2D occurrence. Soil samples from 60 Delta and 60 non-Delta sites randomly selected were analyzed for the presence of OC compounds. A retrospective cohort study of adult men (150 from each region) was recruited to provide a blood sample for OC compound quantitation and select demographic and clinical information including T2D. Using multivariable logistic regression, an association was found between increasing serum DDE levels and T2D occurrence in non-Delta participants (those subjects with lower serum DDE levels), as opposed to Delta participants (individuals with higher serum DDE levels). Thus, while there was a relationship between serum DDE levels and T2D in those with lower burdens of DDE, the lack of association in those with higher levels of DDE indicates a complex non-monotonic correlation between serum DDE levels and T2D occurrence complicating the goal of finding a public health marker for T2D. Abbreviations: BMI, body mass index; CVD, cardiovascular disease; CDC, Center for Disease Control, United States of America; DDE, p,p'- dichlorodiphenyldichloroethylene; DDT, p,p'- dichlorodiphenyltrichloroethane; GC/MS, gas chromatography/mass spectrometry; GIS, geographic information system; GPS, global positioning system; HDL, high-density lipoprotein; HTN, hypertension; IDW, inverse distance weighting; IRB, Institutional Review Board; LDL, low-density lipoprotein; LOQ, limit of quantitation; NHANES, National Health and Nutrition Examination Surveys; POPs, persistent organic pollutants; OC, organochlorine; PCB, polychlorinated biphenyl; SIM, single-ion monitoring; T2D, type 2 diabetes mellitus; USA, United States of America.

Sex-specific effects of blood cadmium on thyroid hormones and thyroid function status: Korean nationwide cross-sectional study

Previous studies on blood cadmium (BCd) and changes in thyroid hormone levels are controversial. We investigated whether thyroid hormone levels and thyroid function status were associated with BCd according to sex in the Korean population. Our study included 1972 participants based on the 2013 Korea National Health and Nutrition Examination Survey (KNHANES) data. Participants whose thyroid-stimulating hormone (TSH) and free thyroxine (fT4) levels were altered physiologically or medically were excluded. Changes in TSH, fT4, and anti-thyroid peroxidase antibody (TPOAb) in men and women were analyzed by different characteristics: age, body mass index (BMI), smoking status, drinking status, BCd, and urine iodine-to-creatinine ratio (UI/Cre). Thyroid function status was classified as hypothyroidism, euthyroidism, and hyperthyroidism as defined by TSH and fT4 levels. Among the total participants, there was a negative correlation between BCd and fT4 (r=-0.067, p = 0.003). In men (n = 1057), fT4 levels decreased with increasing BCd quartile (p-for-trend = 0.002). After adjustment for age, BMI, smoking status, UI/Cre, and TPOAb, the association between BCd and hypothyroidism was significant in men (odds ratio = 1.813, p = 0.032) but not in women. These results suggest that cadmium accumulation is closely associated with thyroid dysfunction, and there is a difference in metabolic capacity according to sex.

Endocrine-disrupting chemicals: Effects on neuroendocrine systems and the neurobiology of social behavior

A contribution to SBN/ICN special issue. Endocrine-disrupting chemicals (EDCs) are pervasive in the environment. They are found in plastics and plasticizers (bisphenol A (BPA) and phthalates), in industrial chemicals such as polychlorinated biphenyls (PCBs), and include some pesticides and fungicides such as vinclozolin. These chemicals act on hormone receptors and their downstream signaling pathways, and can interfere with hormone synthesis, metabolism, and actions. Because the developing brain is particularly sensitive to endogenous hormones, disruptions by EDCs can change neural circuits that form during periods of brain organization. Here, we review the evidence that EDCs affect developing hypothalamic neuroendocrine systems, and change behavioral outcomes in juvenile, adolescent, and adult life in exposed individuals, and even in their descendants. Our focus is on social, communicative and sociosexual behaviors, as how an individual behaves with a same- or opposite-sex conspecific determines that individual's ability to exist in a community, be selected as a mate, and reproduce successfully.

UV-B Filter Octylmethoxycinnamate Induces Vasorelaxation by Ca2+ Channel Inhibition and Guanylyl Cyclase Activation in Human Umbilical Arteries

Ultraviolet (UV) filters are chemicals widely used in personal care products (PCPs). Due to their effect as endocrine disruptor compounds (EDCs), the toxicity of UV filters is a current concern for human health. EDC exposure may be correlated to cardiovascular diseases (CVD), but to our knowledge, no studies assessed the UV filters effects as human EDCs at the vascular level. Octylmethoxycinnamate (OMC) is the world's most widely used UV-B filter, present in more than 90% of PCPs. Due to its demonstrated multiple hormonal activities in animal models, this substance is also suspected to be a human EDC. The purpose of this study was to assess the rapid/short-term effects of OMC on arterial tonus and analyse its mode of action (MOA). Using human umbilical arteries, the endocrine effects of OMC were evaluated in in vitro (cellular and organ) experiments by planar cell surface area (PCSA) and organ bath, respectively. Our data show that OMC induces a rapid/short-term smooth muscle relaxation acting through an endothelium-independent MOA, which seems to be shared with oestrogens, involving an activation of soluble guanylyl cyclase (sGC) that increases the cyclic guanosine monophosphate (cGMP) intracellular levels and an inhibition of L-type voltage-operated Ca²⁺ channels (L-Type VOCC).

Comparative assessment of endocrine disrupting compounds removal in heterotrophic and enriched nitrifying biomass

Despite the number of studies that have investigated the fate of endocrine disrupting compounds (EDCs), to date results are still contradictory and more research is required to evaluate the contribution of the microbial communities present in different engineered treatment systems. Thus, autotrophic and heterotrophic types of biomass were here compared in terms of efficiency in the removal of estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethynilestradiol (EE2) and bisphenol A (BPA). Experiments were performed with enriched nitrifying activated sludge (NAS) and enriched ammonia oxidizing bacteria (AOB) sludge cultivated at lab-scale, as well as with conventional activated sludge (CAS) from a full-scale wastewater treatment plant. Both enriched NAS and AOB demonstrated a negligible degrading capacity. In both cases, the studied EDCs exhibited low removals (<14%) and showed no correlation with the increasing nitrification rates contradicting some of the hypothesis present in literature. Contrariwise, the biodegradation capabilities of the heterotrophic fraction of CAS were highlighted. E2 and E3 were removed by up to 100% and 78%, respectively. E1 was found to be the main transformation product of E2 (almost quantitative oxidation) and it was also highly eliminated. Finally, EE2 and BPA were more persistent biologically with removals ranging from 10% to 39%. For these two compounds similar removals were obtained during experiments with heat-inactivated biomass suggesting that sorption could be a relevant route of elimination.

Endocrine Disrupting Chemicals: An Occult Mediator of Metabolic Disease

Endocrine disrupting chemicals (EDCs), a heterogeneous group of exogenous chemicals that can interfere with any aspect of endogenous hormones, represent an emerging global threat for human metabolism. There is now considerable evidence that the observed upsurge of metabolic disease cannot be fully attributed to increased caloric intake, physical inactivity, sleep deficit, and ageing. Among environmental factors implicated in the global deterioration of metabolic health, EDCs have drawn the biggest attention of scientific community, and not unjustifiably. EDCs unleash a coordinated attack toward multiple components of human metabolism, including crucial, metabolically-active organs such as hypothalamus, adipose tissue, pancreatic beta cells, skeletal muscle, and liver. Specifically, EDCs' impact during critical developmental windows can promote the disruption of individual or multiple systems involved in metabolism, via inducing epigenetic changes that can permanently alter the epigenome in the germline, enabling changes to be transmitted to the subsequent generations. The clear effect of this multifaceted attack is the manifestation of metabolic disease, clinically expressed as obesity, metabolic syndrome, diabetes mellitus, and non-alcoholic fatty liver disease. Although limitations of EDCs research do exist, there is no doubt that EDCs constitute a crucial parameter of the global deterioration of metabolic health we currently encounter.