Endocrine-Disrupting Chemicals: Some Actions of POPs on Female Reproduction

Organic Sunscreens and Their Products of Degradation in Biotic and Abiotic Conditions-In Silico Studies of Drug-Likeness and Human Placental Transport

A total of 16 organic sunscreens and over 160 products of their degradation in biotic and abiotic conditions were investigated in the context of their safety during pregnancy. Drug-likeness and the ability of the studied compounds to be absorbed from the gastrointestinal tract and cross the human placenta were predicted in silico using the SwissADME software (for drug-likeness and oral absorption) and multiple linear regression and "ARKA" models (for placenta permeability expressed as fetus-to-mother blood concentration in the state of equilibrium), with the latter outperforming the MLR models. It was established that most of the studied compounds can be absorbed from the gastrointestinal tract. The drug-likeness of the studied compounds (expressed as a binary descriptor, Lipinski) is closely related to their ability to cross the placenta (most likely by a passive diffusion mechanism). The organic sunscreens and their degradation products are likely to cross the placenta, except for very bulky and highly lipophilic 1,3,5-triazine derivatives; an avobenzone degradation product, 1,2-bis(4-tert-butylphenyl)ethane-1,2-dione; diethylamino hydroxybenzoyl hexyl benzoate; and dimerization products of sunscreens from the 4-methoxycinnamate group.

Novel flame retardants detected in marine plastic litter in coastal areas in Central Chile

Flame retardants (FRs) are released throughout the plastic life cycle, potentially impacting the environment, biodiversity, and human health. This study analyzed novel flame retardants (NFR) in marine plastic litter (MPL) from six coastal areas in central Chile in November 2017. Target chemicals (n = 19) were analyzed using ultrasonic extraction with hexane, gas chromatography, and mass spectrometry (GC-MS). From all nineteen NFRs analyzed, only ten (53 %) were routinely detected. BTBPE (1,2-bis(2,4,6-tribromophenoxy) ethane) showed the highest concentrations at the Bellavista site (618 to 424,000 pg g-1), and HBB (Hexabromobiphenyl), banned since 1970, was detected in Coliumo (2630 to 13,700 pg g-1). These results show emerging transport patterns and underscore the critical need for enhanced waste management practices for MPL in coastal regions to prevent adverse impacts on marine biodiversity.

A realistic mixture of ubiquitous persistent organic pollutants affects bone and cartilage development in zebrafish by interaction with nuclear receptor signaling

"Persistent organic pollutants (POPs)" have a plethora of deleterious effects on humans and the environment due to their bioaccumulative, persistent, and mimicking properties. Individually, each of these chemicals has been tested and its effects measured, however they are rather found as parts of complex mixtures of which we do not fully grasp the extent of their potential consequences. Here we studied the effects of realistic, environmentally relevant mixtures of 29 POPs on cartilage and bone development using zebrafish as a model species. We observed developmental issues in cartilage, in the form of diverse malformations such as micrognathia, reduced size of the Meckel's and other structures. Also, mineralized bone formation was disrupted, hence impacting the overall development of the larvae at later life stages. Assessment of the transcriptome revealed disruption of nuclear receptor pathways, such as androgen, vitamin D, and retinoic acid, that may explain the mechanisms of action of the compounds within the tested mixtures. In addition, clustering of the compounds using their chemical signatures revealed structural similarities with the model chemicals vitamin D and retinoic acid that can explain the effects and/or enhancing the phenotypes we witnessed. Further mechanistic studies will be required to fully understand this kind of molecular interactions and their repercussions in organisms. Our results contribute to the already existing catalogue of deleterious effects caused by exposure to POPs and help to understand the potential consequences in at risk populations.

Insight into the Potential Mechanisms of Endocrine Disruption by Dietary Phytoestrogens in the Context of the Etiopathogenesis of Endometriosis

Phytoestrogens (PEs) are estrogen-like nonsteroidal compounds derived from plants (e.g., nuts, seeds, fruits, and vegetables) and fungi that are structurally similar to 17β-estradiol. PEs bind to all types of estrogen receptors, including ERα and ERβ receptors, nuclear receptors, and a membrane-bound estrogen receptor known as the G protein-coupled estrogen receptor (GPER). As endocrine-disrupting chemicals (EDCs) with pro- or antiestrogenic properties, PEs can potentially disrupt the hormonal regulation of homeostasis, resulting in developmental and reproductive abnormalities. However, a lack of PEs in the diet does not result in the development of deficiency symptoms. To properly assess the benefits and risks associated with the use of a PE-rich diet, it is necessary to distinguish between endocrine disruption (endocrine-mediated adverse effects) and nonspecific effects on the endocrine system. Endometriosis is an estrogen-dependent disease of unknown etiopathogenesis, in which tissue similar to the lining of the uterus (the endometrium) grows outside of the uterus with subsequent complications being manifested as a result of local inflammatory reactions. Endometriosis affects 10-15% of women of reproductive age and is associated with chronic pelvic pain, dysmenorrhea, dyspareunia, and infertility. In this review, the endocrine-disruptive actions of PEs are reviewed in the context of endometriosis to determine whether a PE-rich diet has a positive or negative effect on the risk and course of endometriosis.

Priorities and Challenges in Methodology for Human Health Risk Assessment from Combined Exposure to Multiple Chemicals

This paper reviews key elements in the assessment of human health effects from combined exposure to multiple chemicals taking into consideration current knowledge and challenges to identify areas where scientific advancement is mostly needed and proposes a decision-making scheme on the basis of existing methods and tools. The assumption of dose addition and estimation of the hazard index (HI) is considered as a starting point in component-based risk assessments. When, based on the generic HI approach, an unacceptable risk is identified, more specific risk assessment options may be implemented sequentially or in parallel depending on problem formulation, characteristics of the chemical group under assessment, exposure levels, data availability and resources. For prospective risk assessments, the reference point index/margin of exposure (RPI/MOET) (Option 1) or modified RPI/normalized MOET (mRPI/nMOET) (Option 2) approaches may be implemented focusing on the specific mixture effect. Relative potency factors (RPFs) may also be used in the RPI approach since a common uncertainty factor for each mixture component is introduced in the assessment. Increased specificity in the risk assessment may also be achieved when exposure of selected population groups is considered (Option 3/exposure). For retrospective risk assessments, human biomonitoring data available for vulnerable population groups (Option 3/susceptibility) may present more focused scenarios for consideration in human health risk management decisions. In data-poor situations, the option of using the mixture assessment factor (MAF) is proposed (Option 4), where an additional uncertainty factor is applied on each mixture component prior to estimating the HI. The magnitude of the MAF may be determined by the number of mixture components, their individual potencies and their proportions in the mixture, as previously reported. It is acknowledged that implementation of currently available methods and tools for human health risk assessment from combined exposure to multiple chemicals by risk assessors will be enhanced by ongoing scientific developments on new approach methodologies (NAMs), integrated approaches to testing and assessment (IATA), uncertainty analysis tools, data sharing platforms, risk assessment software as well as guideline development to meet legislative requirements.

Ecological and human health hazards; integrated risk assessment of organochlorine pesticides (OCPs) from the Chenab River, Pakistan

Carcinogenic hazards to human health were investigated through oral and dermal exposure to organochlorine pesticides (OCPs) from water samples (n = 120) of River Chenab, Pakistan. The Pioneering study aimed to employ an integrated geographic information system (GIS) based geostatistical method for the determination of pollution load by GC-ECD from water of River Chenab. The residual levels of OCPs detected from water samples ranged from 0.54 to 122 ng L^-1 with significant prevalence of DDE and α-HCH. Results of the Nemerrow pollution index (NeI), single pollution index (SPI), and comprehensive pollution index (CPI) reflected the downstream zone a stern pollution risk zone. The spatial distribution pattern through geostatistical approaches also revealed significantly higher (p < 0.05) OCP levels in the downstream zone. Risk quotient (RQ_CCC) of surface water quality with respect to heptachlor epitomized a high level of risk (RQ_CCC > 1). Non-carcinogenic human health risk (Σ HQ) assessment ranged from 8.39 × 10^-9 to 1.7 × 10^-3, which represented a marginal risk through oral and dermal exposure. However, carcinogenic risks by oral exposure route were ranged from 3.57 × 10^-11 to 4.46 × 10^-6. Estimated cancer risk (ΣCR) exhibited a considerable carcinogenic risk posed by heptachlor, α-HCH and dieldrin. It is suggested to employ an immediate mitigation strategy for the constant discharge of OCPs in the studied area.

A Realistic Mixture of Persistent Organic Pollutants Affects Zebrafish Development, Behavior, and Specifically Eye Formation by Inhibiting the Condensin I Complex

Persistent organic pollutants (POPs) are posing major environmental and health threats due to their stability, ubiquity, and bioaccumulation. Most of the numerous studies of these compounds deal with single chemicals, although real exposures always consist of mixtures. Thus, using different tests, we screened the effects on zebrafish larvae caused by exposure to an environmentally relevant POP mixture. Our mixture consisted of 29 chemicals as found in the blood of a Scandinavian human population. Larvae exposed to this POP mix at realistic concentrations, or sub-mixtures thereof, presented growth retardation, edemas, retarded swim bladder inflation, hyperactive swimming behavior, and other striking malformations such as microphthalmia. The most deleterious compounds in the mixture belong to the per- and polyfluorinated acids class, although chlorinated and brominated compounds modulated the effects. Analyzing the changes in transcriptome caused by POP exposure, we observed an increase of insulin signaling and identified genes involved in brain and eye development, leading us to propose that the impaired function of the condensin I complex caused the observed eye defect. Our findings contribute to the understanding of POP mixtures, their consequences, and potential threats to human and animal populations, indicating that more mechanistic, monitoring, and long-term studies are imperative.

The toxicological profile of polychlorinated naphthalenes (PCNs)

The legacy of polychlorinated naphthalenes (PCNs) manufactured during the last century continues to persist in the environment, food and humans. Metrological advances have improved characterisation of these occurrences, enabling studies on the effects of exposure to focus on congener groups and individual PCNs. Liver and adipose tissue show the highest retention but significant levels of PCNs are also retained by the brain and nervous system. Molecular configuration appears to influence tissue disposition as well as retention, favouring the higher chlorinated (≥ four chlorines) PCNs while most lower chlorinated molecules readily undergo hydroxylation and excretion through the renal system. Exposure to PCNs reportedly provokes a wide spectrum of adverse effects that range from hepatotoxicity, neurotoxicity and immune response suppression along with endocrine disruption leading to reproductive disorders and embryotoxicity. A number of PCNs, particularly hexachloronaphthalene congeners, elicit AhR mediated responses that are similar to, and occur within similar potency ranges as most dioxin-like polychlorinated biphenyls (PCBs) and some chlorinated dibenzo-p-dioxins and furans (PCDD/Fs), suggesting a relationship based on molecular size and configuration between these contaminants. Most toxicological responses generally appear to be associated with higher chlorinated PCNs. The most profound effects such as serious and sometimes fatal liver disease, chloracne, and wasting syndrome resulted either from earlier episodes of occupational exposure in humans or from acute experimental dosing of animals at levels that reflected these exposures. However, since the restriction of manufacture and controls on inadvertent production (during combustion processes), the principal route of human and animal exposure is likely to be dietary intake. Therefore, further investigations should include the effects of chronic lower level intake of higher chlorinated PCN congeners that persist in the human diet and subsequently in human and animal tissues. PCNs in the diet should be evaluated cumulatively with other similarly occurring dioxin-like contaminants.

Reproductive toxicity induced by benzo[a]pyrene exposure: first exploration highlighting the multi-stage molecular mechanism in female scallop Chlamys farreri

Reproductive toxicity induced by benzo[a]pyrene (B[a]P) exposure has received great ecotoxicological concerns. However, huge gaps on the molecular mechanism still exist in bivalves. In this study, reproduction-related indicators were investigated in female scallops Chlamys farreri during life cycle of proliferative, growth, mature, and spawn stages, under gradient concentrations of B[a]P at 0, 0.04, 0.4, and 4 μg/L. Meanwhile, a multi-stage ovarian transcriptome analysis under 4 μg/L B[a]P exposure was also conducted to elucidate the potential molecular mechanisms. The results indicated that life-cycle exposure to 0.4 and 4 μg/L B[a]P significantly decreased GSI and sex steroid levels. Even 0.04 μg/L B[a]P could play the adverse role in DNA integrity at the mature and spawn stages. Ovarian histological sections showed that B[a]P inhibited the maturation and release of oocytes. Through the functional enrichment analysis of differentially expressed genes (DEGs) from transcriptome data, 18 genes involved in endocrine disruption effects, DNA damage and repair, and oogenesis were selected and further determined by qRT-PCR. The downregulation of genes involved in steroidogenic and estrogen signaling pathways indicated that B[a]P could cause endocrine disruption through both receptor-dependent and receptor-independent pathways. The variations of gene expressions involved in DNA single-strand break and repair implied the presence of toxic mechanisms similar with vertebrates. Additionally, the changes of gene expressions of cell cycle, apoptosis, and cell adhesion suggested that exposure to B[a]P possibly caused the reproductive toxicity effects by affecting oogenesis. Taken together, this study was a pioneer in combining genome-wide transcriptomic analysis with its corresponding reproductive indicators (GSI, sex steroid levels, DNA single-strand break, and histological sections) to explore the bivalves' toxic mechanisms under B[a]P exposure. Meanwhile, some genes involved in estrogen signaling pathway and DNA damage were firstly analyzed in bivalves, and the expression data might be useful in establishing new hypotheses and discovering new biomarkers for marine biomonitoring.

Environmental Phenol and Paraben Exposure Risks and Their Potential Influence on the Gene Expression Involved in the Prognosis of Prostate Cancer

Prostate cancer (PCa) is one of the leading malignant tumors in US men. The lack of understanding of the molecular pathology on the risk of food supply chain exposures of environmental phenol (EP) and paraben (PB) chemicals limits the prevention, diagnosis, and treatment options. This research aims to utilize a risk assessment approach to demonstrate the association of EP and PB exposures detected in the urine samples along with PCa in US men (NHANES data 2005−2015). Further, we employ integrated bioinformatics to examine how EP and PB exposure influences the molecular pathways associated with the progression of PCa. The odds ratio, multiple regression model, and Pearson coefficients were used to evaluate goodness-of-fit analyses. The results demonstrated associations of EPs, PBs, and their metabolites, qualitative and quantitative variables, with PCa. The genes responsive to EP and PB exposures were identified using the Comparative Toxicogenomic Database (CTD). DAVID.6.8, GO, and KEGG enrichment analyses were used to delineate their roles in prostate carcinogenesis. The plug-in CytoHubba and MCODE completed identification of the hub genes in Cytoscape software for their roles in the PCa prognosis. It was then validated by using the UALCAN database by evaluating the expression levels and predictive values of the identified hub genes in prostate cancer prognosis using TCGA data. We demonstrate a significant association of higher levels of EPs and PBs in the urine samples, categorical and numerical confounders, with self-reported PCa cases. The higher expression levels of the hub genes (BUB1B, TOP2A, UBE2C, RRM2, and CENPF) in the aggressive stages (Gleason score > 8) of PCa tissues indicate their potential role(s) in the carcinogenic pathways. Our results present an innovative approach to extrapolate and validate hub genes responsive to the EPs and PBs, which may contribute to the severity of the disease prognosis, especially in the older population of US men.

Effect of Environmental Stressors, Xenobiotics, and Oxidative Stress on Male Reproductive and Sexual Health

This article examines the environmental factor-induced oxidative stress (OS) and their effects on male reproductive and sexual health. There are several factors that induce OS, i.e. radition, metal contamination, xenobiotic compounds, and cigarette smoke and lead to cause toxicity in the cells through metabolic or bioenergetic processes. These environmental factors may produce free radicals and enhance the reactive oxygen species (ROS). Free radicals are molecules that include oxygen and disbalance the amount of electrons that can create major chemical chains in the body and cause oxidation. Oxidative damage to cells may impair male fertility and lead to abnormal embryonic development. Moreover, it does not only cause a vast number of health issues such as ageing, cancer, atherosclerosis, insulin resistance, diabetes mellitus, cardiovascular diseases, ischemia-reperfusion injury, and neurodegenerative disorders but also decreases the motility of spermatozoa while increasing sperm DNA damage, impairing sperm mitochondrial membrane lipids and protein kinases. This chapter mainly focuses on the environmental stressors with further discussion on the mechanisms causing congenital impairments due to poor sexual health and transmitting altered signal transduction pathways in male gonadal tissues.

Assessing the chemical-induced estrogenicity using in silico and in vitro methods

Multiple substances are considered endocrine disrupting chemicals (EDCs). However, there is a significant gap in the early prioritization of EDC's effects. In this work, in silico and in vitro methods were used to model estrogenicity. Two Quantitative Structure-Activity Relationship (QSAR) models based on Logistic Regression and REPTree algorithms were built using a large and diverse database of estrogen receptor (ESR) agonism. A 10-fold external validation demonstrated their robustness and predictive capacity. Mechanistic interpretations of the molecular descriptors (C-026, nArOH,PW5, B06[Br-Br]) used for modelling suggested that the heteroatomic fragments, aromatic hydroxyls, and bromines, and the relative bond accessibility areas of molecules, are structural determinants in estrogenicity. As validation of the QSARs, ESR transactivity of thirteen persistent organic pollutants (POPs) and suspected EDCs was tested in vitro using the MMV-Luc cell line. A good correspondence between predictions and experimental bioassays demonstrated the value of the QSARs for prioritization of ESR agonist compounds.

Air pollution-induced epigenetic changes: disease development and a possible link with hypersensitivity pneumonitis

Air pollution is a serious threat to our health and has become one of the major causes of many diseases including cardiovascular disease, respiratory disease, and cancer. The association between air pollution and various diseases has long been a topic of research interest. However, it remains unclear how air pollution actually impacts health by modulating several important cellular functions. Recently, some evidence has emerged about air pollution-induced epigenetic changes, which are linked with the etiology of various human diseases. Among several epigenetic modifications, DNA methylation represents the most prominent epigenetic alteration underlying the air pollution-induced pathogenic mechanism. Several other types of epigenetic changes, such as histone modifications, miRNA, and non-coding RNA expression, have also been found to have been linked with air pollution. Hypersensitivity pneumonitis (HP), one of the most prevalent forms of interstitial lung diseases (ILDs), is triggered by the inhalation of certain organic and inorganic substances. HP is characterized by inflammation in the tissues around the lungs' airways and may lead to irreversible lung scarring over time. This review, in addition to other diseases, attempts to understand whether certain pollutants influence HP development through such epigenetic modifications.

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.

Congenital heart diseases and parental occupational exposure in a Hungarian case-control study in 1997 to 2002

The etiology of congenital heart diseases is not fully understood yet, however, endocrine disrupting chemicals may have a causative role in their development. The purpose of our study was to examine the association between congenital heart diseases and periconceptional parental occupational exposure to endocrine disrupting chemicals. In our Hungarian population-based case-control study, we examined 2263 live born cases with any congenital heart disease and 6789 matched controls selected between years 1997 to 2002. Occupational exposure was assessed with a job-exposure matrix developed for endocrine disrupting chemicals. Conditional multiple logistic regression analyses were performed to test associations between parental occupational exposure to endocrine disrupting chemicals and congenital heart diseases of the offspring as a whole and by congenital heart disease subtypes. The prevalence of exposure to endocrine disrupting chemicals was 4.5% for both case and control mothers and 19.1% and 19.4% for case and control fathers, respectively. We found a positive association between paternal pesticide (adjusted odds ratio = 1.66, 95% confidence interval: 1.03-2.69) and alkylphenolic compound exposure (adjusted odds ratio = 1.95, 95% confidence interval: 1.30-2.93) and the development of patent ductus arteriosus in the offspring. Alkylphenolic compound exposure occurred among painters, famers, and those working in the food service industry, while pesticide exposure occurred predominantly among farm workers. We identified that certain occupations may increase the occurrence of certain congenital heart disease phenotypes in the offspring. By paying closer attention to those working in these areas, antenatal detection rates of congenital heart diseases may be improved.

Chlorinated and brominated persistent compounds in hard coral, soft coral, and parrotfish from remote Mascarene islands

Persistent halogenated compounds (PHC) are of concern for human and environmental health. Persistent Organic Pollutants (POPs) are regulated by international treaties, but alternative compounds such as novel brominated flame retardants (NBFRs) and Dechlorane Plus (DP) are not-yet they are increasingly used. There are no data on PHCs in coral reef biota from tropical islands in the western Indian Ocean (WIO). For this assessment, three hard coral genera, two soft coral genera, and ember parrotfish (Scarus rubroviolaceus) were collected from the remote Rodrigues, Agalega, and St. Brandon's Atoll (Republic of Mauritius) in the Mascarene Basin of the WIO. Five compounds - Pentabromotoluene (PBT), γ-HCH, p,p'-DDE, HCB, and BDE-47- were quantifiable in all samples. Hard coral consistently contained the lowest concentrations of PHCs, except for NBFRs. The presence of BDE-47 suggests long-range aerial transport. We quantified DP, currently a candidate POP, in coral reef biota. PBT was measured in all samples also suggests long-range transport. Because the hard coral, soft coral, and fish had differing concentrations and patterns of PHCs, future surveys should stratify sampling accordingly. Agalega and St. Brandon's Atoll can be considered as locations to monitor changes in background concentrations of pollutants due to their remoteness.

[Effects of bisphenol A on apoptosis of ovarian preantral follicular granulosa cells and ovarian development in mice]

OBJECTIVE

To investigate the effect of environmental estrogen bisphenol A (BPA) exposure on apoptosis of mouse ovarian preantral follicular granulosa cells and ovarian development and explore the underlying mechanism.

METHODS

Mouse ovarian preantral follicular granulosa cells were isolated from female ICR mice at postnatal day (PND) 10 and cultured in vitro. The cultured cells were treated with 0, 1, 10, 50, 100, 150, 200 and 500 μmol/L BPA, and the changes in cell proliferation, cell cycle, apoptosis and mitochondrial membrane potential were analyzed with CCK-8 method and flow cytometry. The protein expressions of Bcl-2, Bax, p53 and cyclin D1 in the treated cells were determined with Western blotting. Pregnant ICR mice were treated for a week with BPA at the concentration that produced significant effects on the preantral follicular granulosa cells, and the weight changes of the pregnant mice were recorded. The ovarian tissues of the offspring female mice were weighed at PND 10, 17, 21 and 42 followed by histological observation with HE staining and examination of Bcl-2 mRNA expression level with RT-qPCR.

RESULTS

Compared with the control cells group, the isolated cells exposed to a low concentration of BPA (50 μmol/L) showed a significantly lowered apoptosis rate, increased mitochondrial membrane potential, and enhanced cellular proliferation (P < 0.05). Exposure to a higher BPA concentration at 200 μmol/L obviously enhanced cell apoptosis by reducing the mitochondrial membrane potential and repressed the cell proliferation (P < 0.05). BPA exposure at 50 μmol/L and 200 μmol/L produced opposite effects on the protein expressions of Bcl-2 (P < 0.01), Bax (P < 0.05) and p53 (P < 0.05) in mouse ovarian preantral follicular granulosa cells. BPA exposure at the doses of 10 and 35 mg/kg caused rapid weight increment of the pregnant mice and changes in ovarian index of the offspring female mice. In the offspring female mice, the changes in Bcl-2 mRNA expression in the ovarian tissue showed a similar pattern to that of ovarian index. Exposure of the pregnant mice to a high BPA concentration at 35 mg/kg resulted in accelerated follicular development into antral follicular stage in PND 21 offspring female mice.

CONCLUSIONS

BPA can concentration-dependently regulate the function of ovarian preantral follicular granulosa cells in mice and potentially affects both the pregnant mice and the offspring female mice in light of early ovarian development.

Parental occupational exposure and congenital heart diseases in a Hungarian case-control study

Purpose

Our study aimed to explore the effect of parental occupational exposure to endocrine disrupting chemicals (EDCs) on the development of congenital heart diseases (CHDs) in the offspring, and to compare job-exposure matrix (JEM)-assessed and self-reported occupational exposures with each other.

Methods

Live-born infants born in 2007–2008 were selected from the population-based Hungarian Case–Control Surveillance of Congenital Abnormalities Study. 577 cases with any CHDs were compared to 1731 matched controls. Parental periconceptional occupational exposure to EDCs was assessed by a JEM and by questionnaire-based self-reporting of parents. Multivariate conditional logistic regression analyses were conducted to explore associations between parental occupational exposure to EDCs and the entire spectrum of CHDs and by CHD subtypes in the offspring. Kappa statistics were also performed to determine the consistency among JEM-assessed and self-reported occupational exposure of parents.

Results

JEM-assessed paternal exposure to polychlorinated organic substances, phthalates, biphenolic compounds, and solvents were significantly associated with the entire spectrum of CHDs. Ventricular septal defects were significantly associated with paternal self-reported exposure to pesticides, while atrial septal defects were significantly associated to paternal JEM-assessed phthalate exposure. Paternal solvent exposure was significantly associated with atrial septal defects and right ventricle outflow tract obstructions. JEM-assessed and self-reported exposures to pesticides, heavy metals, and solvents exhibited poor agreement for mothers and slight agreement for fathers.

Conclusion

Even though parental occupational exposure to EDCs seems to have a minor impact on the occurrence of CHDs, the results of biological and environmental monitoring should be taken into consideration as well.

Feces are Effective Biological Samples for Measuring Pesticides and Flame Retardants in Primates

The habitats of wild primates are increasingly threatened by surrounding anthropogenic pressures, but little is known about primate exposure to frequently used chemicals. We applied a novel method to simultaneously measure 21 legacy pesticides (OCPs), 29 current use pesticides (CUPs), 47 halogenated flame retardants (HFRs), and 19 organophosphate flame retardants in feces from baboons in the U.S.A., howler monkeys in Costa Rica, and baboons, chimpanzees, red-tailed monkeys, and red colobus in Uganda. The most abundant chemicals were α-hexachlorocyclohexane (α-HCH), β-hexachlorocyclohexane (β-HCH), and hexachlorobenzene among OCPs across all sites, chlorpyrifos among CUPs in Costa Rica and Indiana, decabromodiphenylethane (DBDPE) in Costa Rica and Indiana and 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47) in Uganda as HFRs, and tris(2-butoxyethyl) phosphate (TBOEP) as OPFRs across all sites. The detected chemical concentrations were generally higher in red-tailed monkeys and red colobus than in chimpanzees and baboons. Our methods can be used to examine the threat of chemical pollutants to wildlife, which is critical for endangered species where only noninvasive methods can be used.

Bioaccumulation of persistent organic pollutants in the gonads of Barbus barbus (Linnaeus, 1758)

Maps with grey or even white spaces are still present in spite of the fact that persistent organic pollutants (POPs) are at the forefront of research in aquatic toxicology and environmental safety. This is also the case for the Mureș River basin. The intensive use of industrial substances such as polychlorinated biphenyls (PCBs) and pesticides such as organochlorine compounds (OCPs) has caused global contamination of the aquatic environment. In our study we have found very high concentrations of both PCBs (2110-169,000 ng/g lipid weight ΣPCB, 1950-166,000 ng/g lipid weight ΣPCB₇) and OCPs (1130-7830 ng/g lipid weight ΣDDT, 47.6-2790 ng/g lipid weight ΣHCH, 5.53-35.6 ng/g lipid weight ΣChlordane, and 6.74-158 ng/g lipid weight HCB) in the gonad tissue of Barbus barbus (Linnaeus, 1758) males and females. Contrary to most studies where the weight, length, and lipid percentage are positively correlated with the concentration of POPs from different tissue types, we observed a downward trend for the lipid normalized concentrations of some pollutants in gonads while these indices were actually increasing. The decrease of lipid normalized POPs with the increase of CF and lipid percentage may be due to the fact that individuals are eliminating hard and soft roes every year during reproduction which could mean that some quantities of pollutants are also eliminated along with the hard and soft roes. The high POPs concentrations found in our study should be a needed wakeup call for environmentalists and a starting point in developing monitoring and management measures for these pollutants.

Characterization of 9 Gas Chromatography Columns by Linear and Lee Retention Indices for Polychlorinated Biphenyls and Polychlorinated Naphthalenes

Polychlorinated biphenyls (PCBs) and naphthalenes (PCNs) are ubiquitous environmental contaminants with varying degrees of toxicity. There are hundreds of possible congeners with similar chemical characteristics, which make these compounds difficult to isolate in environmental samples. Historically, PCBs and PCNs were identified by using an Aroclor or Halowax mixture instead of the individual compounds, which was impractical because of limited numbers of individual standards. A retention index database was developed with all 209 PCBs and 36 PCNs to help identify these chemicals in environmental and biological matrixes. This study uses linear and Lee retention indices to identify all 209 PCBs and 36 PCNs on nine gas chromatography columns. The most toxic congeners, the 12 dioxin-like PCBs, were compared across all columns to determine which stationary phases gave the best selectivity for those compounds. Column selectivity was also examined to determine columns for confirmatory analyses and GC×GC separations. The Rxi-17SilMS demonstrated the most drastic difference in PCB selectivity and, to a lesser extent, PCNs when compared with the other eight columns and could work as a confirmatory column or as a 2nd dimension column for GC×GC separations.

Biphasic Dose-Response Induced by PCB150 and PCB180 in HeLa Cells and Potential Molecular Mechanisms

The polychlorinated biphenyls (PCBs) are persistent and their dose-dependent toxicities studies are not well-established. In this study, cytotoxic and genotoxic effects of PCB150 and PCB180 in HeLa cells were studied. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that the cell proliferation was stimulated at low doses (10⁻³ and 10⁻² µg/mL for 12, 24, 48, and 72 hours) and inhibited at high doses (10 and 15 µg/mL for 24, 48, and 72 hours) for both PCBs. Increase in reactive oxygen species formation was observed in the HeLa cells in a time- and dose-dependent manner. Malondialdehyde and superoxide dismutase showed increased levels at high concentrations of PCBs over the time. Glutathione peroxidase expression was downregulated after PCBs exposure, suggested that both PCB congeners may attributable to cytotoxicity. Comet assay elicited a significant increase in genotoxicity at high concentrations of PCBs as compared to low concentrations indicating genotoxic effects. PCB150 and PCB180 showed decrease in the activity of extracellular signal–regulated kinase 1/2 and c-Jun N-terminal kinase at high concentrations after 12 and 48 hours. These findings may contribute to understanding the mechanism of PCBs-induced toxicity, thereby improving the risk assessment of toxic compounds in humans.

Bisphenol A: an emerging threat to female fertility

Bisphenol-A (BPA) has been reported to be associated to female infertility. Indeed, BPA has been found to be more frequently detected in infertile women thus leading to hypothesize a possible effect of BPA on natural conception and spontaneous fecundity. In addition, in procedures of medically assisted reproduction BPA exposure has been found to be negatively associated with peak serum estradiol levels during gonadotropin stimulation, number of retrieved oocytes, number of normally fertilized oocytes and implantation. BPA deleterious effects are more critical during perinatal exposure, causing dysregulation of hypothalamic-pituitary-ovarian axis in pups and adults, with a precocious maturation of the axis through a damage of GnRH pulsatility, gonadotropin signaling and sex steroid hormone production. Further, BPA exposure during early lifestage may have a transgenerational effect predisposing the subsequent generations to the risk of developing BPA related disease. Experimental studies suggested that prenatal, perinatal and postnatal exposure to BPA can impair several steps of ovarian development, induce ovarian morphology rearrangement and impair ovarian function, particularly folliculogenesis, as well as can impair uterus morphology and function, in female adult animal and offspring. Finally, studies carried out in animal models have been reported the occurrence of endometriosis-like lesions after BPA exposure. Moreover, BPA exposure has been described to encourage the genesis of PCOS-like abnormalities through the impairment of the secretion of sex hormones affecting ovarian morphology and functions, particularly folliculogenesis. The current manuscript summarizes the evidence regarding the association between BPA exposure and female infertility, reviewing both clinical and preclinical studies.

Nitrophenols suppress steroidogenesis in prehierarchical chicken ovarian follicles by targeting STAR, HSD3B1, and CYP19A1 and downregulating LH and estrogen receptor expression

To assess the effects of 4-nitrophenol (PNP) and 3-methyl-4-nitrophenol (PNMC) on steroidogenesis in the chicken ovary, white (WF, 1-4 mm) and yellowish (YF, 4-8 mm) prehierarchical follicles were incubated in a medium supplemented with PNP or PNMC (10^-8-10^-4 M), ovine LH (oLH; 10 ng/mL), and combinations of oLH with PNP or PNMC (10^-6 M). Testosterone (T) and estradiol (E2) concentrations in media and mRNA expression for steroidogenic proteins (STAR, HSD3B1, and CYP19A1), and LH receptors (LHR), estrogen receptor α (ESR1) and β (ESR2) in follicles were determined by RIA and real-time qPCR, respectively. PNP and PNMC decreased T and E2 secretion by the WF and YF, and oLH-stimulated T secretion from these follicles. PNP decreased basal STAR and HSD3B1 mRNA levels both in the WF and YF, and CYP19A1 mRNAs in the WF. PNP reduced oLH-affected mRNA expression of these genes in the YF. PNMC inhibited basal STAR, HSD3B1, and CYP19A1 mRNA expression in the WF, but not in the YF. PNMC reduced oLH-stimulated STAR and CYP19A1 expression in the YF and WF, respectively. PNP decreased basal mRNA expression of LHR, ESR1, and ESR2 in the WF, but it increased ESR1 and ESR2 mRNA levels in the YF. PNMC reduced both basal and oLH-affected LHR, ESR1, and ESR2 mRNA expression in the WF; however, it did not influence expression of these genes in the YF. We suggest that nitrophenols by influencing sex steroid synthesis and transcription of LH and estrogen receptors in prehierarchical ovarian follicles may impair their development and selection to the preovulatory hierarchy.

Persistent Organic Pollutants in Food: Contamination Sources, Health Effects and Detection Methods

Persistent organic pollutants (POPs) present in foods have been a major concern for food safety due to their persistence and toxic effects. To ensure food safety and protect human health from POPs, it is critical to achieve a better understanding of POP pathways into food and develop strategies to reduce human exposure. POPs could present in food in the raw stages, transferred from the environment or artificially introduced during food preparation steps. Exposure to these pollutants may cause various health problems such as endocrine disruption, cardiovascular diseases, cancers, diabetes, birth defects, and dysfunctional immune and reproductive systems. This review describes potential sources of POP food contamination, analytical approaches to measure POP levels in food and efforts to control food contamination with POPs.

Folic acid supplementation reduces multigenerational sperm miRNA perturbation induced by in utero environmental contaminant exposure

Persistent organic pollutants (POPs) can induce epigenetic changes in the paternal germline. Here, we report that folic acid (FA) supplementation mitigates sperm miRNA profiles transgenerationally following in utero paternal exposure to POPs in a rat model. Pregnant founder dams were exposed to an environmentally relevant POPs mixture (or corn oil) ± FA supplementation and subsequent F1-F4 male descendants were not exposed to POPs and were fed the FA control diet. Sperm miRNA profiles of intergenerational (F1, F2) and transgenerational (F3, F4) lineages were investigated using miRNA deep sequencing. Across the F1-F4 generations, sperm miRNA profiles were less perturbed with POPs+FA compared to sperm from descendants of dams treated with POPs alone. POPs exposure consistently led to alteration of three sperm miRNAs across two generations, and similarly one sperm miRNA due to POPs+FA; which was in common with one POPs intergenerationally altered sperm miRNA. The sperm miRNAs that were affected by POPs alone are known to target genes involved in mammary gland and embryonic organ development in F1, sex differentiation and reproductive system development in F2 and cognition and brain development in F3. When the POPs treatment was combined with FA supplementation, however, these same miRNA-targeted gene pathways were perturbed to a lesser extend and only in F1 sperm. These findings suggest that FA partially mitigates the effect of POPs on paternally derived miRNA in a intergenerational manner.

Comparative study of environmental pollutants bisphenol A and bisphenol S on sexual differentiation of anteroventral periventricular nucleus and spermatogenesis

BACKGROUND

Bisphenol A is well known endocrine-disrupting chemical while Bisphenol S was considered a safe alternative. The present study aims to examine the comparative effects of xenobiotic bisphenol-A (BPA) and its substitute bisphenol-S (BPS) on spermatogenesis and development of sexually dimorphic nucleus population of dopaminergic neurons in the anteroventral periventricular nucleus (AVPV) of the hypothalamus in male pups.

METHODS

Sprague Dawley rat's pups were administered subcutaneously at the neonatal stage from postnatal day PND1 to PND 27. Thirty animals were divided into six experimental groups (6 animals/group). The first group served as control and was provided with normal olive oil. The four groups were treated with 2 μg/kg and 200 μg/kg of BPA and BPS, respectively. The sixth group was given with 50 μg/kg of estradiol dissolved in olive oil as a standard to find the development of dopaminergic tyrosine hydroxylase neurons in AVPV regions. Histological analysis for testicular tissues and immunohistochemistry for brain tissues was performed.

RESULTS

The results revealed adverse histopathological changes in testis after administration of different doses of BPA and BPS. These degenerative changes were marked by highly significant (p < 0.001) decrease in tubular and luminal diameters of seminiferous tubule and epithelial height among bisphenols treated groups as compared to control. Furthermore, significantly increased (p < 0.001) TH-ir cell bodies in the AVPV region of the brain with 200 μg/kg dose of BPA and BPS was evident.

CONCLUSION

It is concluded that exposure of BPA and BPS during a critical developmental period can structural impairments in testes and affects sexual differentiation of a dimorphic dopaminergic population of AVPV region of hypothalamus in the male brain.

Pharmacologic and Environmental Endocrine Disruptors in the Pathogenesis of Hypospadias: a Review

PURPOSE OF REVIEW

Endocrine disrupting chemicals (EDCs) potentially have a role in causing hypospadias malformation through modifiable in-utero exposure. Considering the emerging literature on the role of potential endocrine disrupting substances on the occurrence of hypospadias and the potential to inform public health efforts to prevent the occurrence of these malformations, we have summarized the current literature, identified areas of consensus, and highlighted areas that warrant further investigation.

RECENT FINDINGS

Pharmaceuticals, such as diethylstilbestrol, progestin fertility treatments, corticosteroids, and valproic acid, have all been associated with hypospadias risk. Data on exposure to dichlorodiphenyltrichloroethane and hexachlorobenzene pesticides, as well as non-persistent pollutants, particularly phthalates, is less consistent but still compelling. Improving exposure assessment, standardizing sample timing to relevant developmental windows, using clear case identification and classification schemes, and elucidating dose-response relationships with EDCs will help to provide clearer evidence. Promising directions for future research include identification of subgroups with genetic hypospadias risk factors, measurement of intermediate outcomes, and study of EDC mixtures that will more accurately represent the total fetal environment.

Associations between endocrine disrupting chemicals and equine metabolic syndrome phenotypes

Equine Metabolic Syndrome (EMS) is characterized by abnormalities in insulin regulation, increased adiposity and laminitis, and has several similarities to human metabolic syndrome. A large amount of environmental variability in the EMS phenotype is not explained by commonly measured factors (diet, exercise, and season), suggesting that other environmental factors play a role in EMS development. Endocrine disrupting chemicals (EDCs) are associated with metabolic syndrome and other endocrine abnormalities in humans. This led us to hypothesize that EDCs are detectable in horse plasma and play a role in the pathophysiology of EMS. EDCs acting through the aryl hydrocarbon and estrogen receptors, were measured in plasma of 301 horses from 32 farms. The median (range) TEQ (2,3,7,8-TCDD equivalent) and EEQ (17β-estradiol equivalent) were 19.29 pg/g (0.59-536.36) and 10.50 pg/ml (4.35-15000.00), respectively. TEQ was negatively associated with plasma fat extracted and batch analyzed. EEQ was positively associated with pregnancy and batch analyzed, and negatively associated with being male and superfund score ≤100 miles of the farm. Of particular interest, serum glucose and insulin, glucose and insulin post oral sugar challenge, and leptin concentrations were associated with EEQ, and serum triglyceride concentration was associated with TEQ. Overall, we demonstrated that EDCs are present in the plasma of horses and may explain some of the environmental variability in measured EMS phenotypes. This is the first example of EDCs being associated with clinical disease phenotype components in domestic animals.

Evaluation of selected polychlorinated biphenyls (PCBs) congeners and dichlorodiphenyltrichloroethane (DDT) in fresh root and leafy vegetables using GC-MS

Persistent organic pollutants (POPs) are dangerous and toxic pollutants that may cause adverse effects on human and animal health, including death. POPs such as polychlorinated biphenyls (PCBs) and pesticides are subtly released into the environment from industrial and agricultural use. Global circulation is due to their trans-boundary transport capacity, contingent on aerodynamic and hydrological properties. Plants have capacity to take-up POPs, and these bio-magnify along heterotrophic transfer pathways. In this study, levels of selected 6-PCB congeners and 3- DDTs in some leaf and root vegetables were investigated. Leaf and root vegetables were collected from different horticultural farms areas in Cape Town. The 6-PCBs and 3-DDTs were recovered from the samples using solid phase extraction(SPE), followed by GC-MS analysis. The ΣPCBs and ΣDDT (on-whole basis), were ranged: 90.9–234 ng/g and 38.9–66.1 ng/g respectively. The 3-PCBs and 6-DDTs levels were slightly higher in leaf vegetables compared to root vegetables. The detection of PCBs and DDTs in the vegetables suggest the probable use of PCBs containing pesticides. Although the observed concentrations were below the WHO maximum residue limits, consumption of such contaminated leaf and root vegetables portend a health risk.

The Impact of Bisphenol A on Fertility, Reproductive System, and Development: A Review of the Literature

Bisphenol A (BPA) has been used since the 1950s, in food packaging, industrial materials, dental sealants, and personal hygiene products. Everyone is exposed to BPA through skin, inhalation, and digestive system. BPA disrupts endocrine pathways, because it has weak estrogenic, antiandrogenic, and antithyroid activities. Despite the rapid metabolism, BPA can accumulate in different tissues. Many researchers proved the impact of BPA on human development, metabolism, and finally reproductive system. There is increasing evidence that BPA has impact on human fertility and is responsible for the reproductive pathologies, e.g., testicular dysgenesis syndrome, cryptorchidism, cancers, and decreased fertility in male and follicle loss in female.

Interactions Between Bisphenol A Exposure and GSTP1 Polymorphisms in Childhood Asthma

Purpose

Bisphenol A (BPA) exposure may increase the risk of asthma. Genetic polymorphisms of oxidative stress-related genes, glutathione S-transferases (GSTM1, GSTP1), manganese superoxide dismutase, catalase, myeloperoxidase, and microsomal epoxide hydrolase may be related to BPA exposure. The aim is to evaluate whether oxidative stress genes modulates associations of BPA exposure with asthma.

Methods

We conducted a case-control study comprised of 126 asthmatic children and 327 controls. Urine Bisphenol A glucuronide (BPAG) levels were measured by ultra-performance liquid chromatography/tandem mass spectrometry, and genetic variants were analyzed by a TaqMan assay. Information on asthma and environmental exposure was collected. Analyses of variance and logistic regressions were performed to determine the association of genotypes and urine BPAG levels with asthma.

Results

BPAG levels were significantly associated with asthma (adjusted odds ratio [aOR], 1.29 per log unit increase in concentration; 95% confidence interval [CI], 1.081.55). Compared to the GG genotype, children with a GSTP1 AA genotype had higher urine BPAG concentrations (geometric mean [standard error], 12.72 [4.16] vs 11.42 [2.82]; P=0.036). In children with high BPAG, the GSTP1 AA genotype was related to a higher odds of asthma than the GG genotype (aOR, 4.84; 95% CI, 1.0223.06).

Conclusions

GSTP1 variants are associated with urine BPA metabolite levels. Oxidative stress genes may modulate the effect of BPA exposure on asthma.

Aryl hydrocarbon receptor and unexplained miscarriage

AIM

The aim of this study was to carry out a preliminary investigation of the expression of aryl hydrocarbon receptor (AhR) in decidua and villus and the relationship between AhR and unexplained miscarriage.

METHODS

The expression of AhR mRNA and protein from decidua and villus were measured using real-time reverse transcription-polymerase chain reaction, western blot and immunohistochemistry in 34 patients with unexplained miscarriage (miscarriage group) and 38 women with normal early pregnancy (control group).

RESULTS

The AhR mRNA and protein expression was increased significantly in the villus in both groups compared with decidua (P < 0.05, P < 0.05). In decidua, AhR mRNA and protein expression in the miscarriage group was increased significantly compared with the control group (P < 0.05, P < 0.05). In villus, AhR mRNA and protein expression in the miscarriage group was increased significantly compared with the control group (P < 0.05, P < 0.05). AhR is expressed mostly in the cytoplasm of syncytiotrophoblasts in villus, and also in the cytoplasm of decidual cells.

CONCLUSIONS

AhR was expressed more in the villus than in the decidua, and the upregulation of AhR mRNA and protein expression is associated with the pathogenesis of unexplained miscarriage.

Environmental pollutants, a possible etiology for premature ovarian insufficiency: a narrative review of animal and human data

BACKGROUND

Because only 25% of cases of premature ovarian insufficiency (POI) have a known etiology, the aim of this review was to summarize the associations and mechanisms of the impact of the environment on this pathology. Eligible studies were selected from an electronic literature search from the PUBMED database from January 2000 to February 2016 and associated references in published studies. Search terms included ovary, follicle, oocyte, endocrine disruptor, environmental exposure, occupational exposure, environmental contaminant, pesticide, polyaromatic hydrocarbon, polychlorinated biphenyl PCB, phenol, bisphenol, flame retardant, phthalate, dioxin, phytoestrogen, tobacco, smoke, cigarette, cosmetic, xenobiotic. The literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We have included the human and animal studies corresponding to the terms and published in English. We have excluded articles that included results that did not concern ovarian pathology and those focused on ovarian cancer, polycystic ovary syndrome, endometriosis or precocious puberty. We have also excluded genetic, auto-immune or iatrogenic causes from our analysis. Finally, we have excluded animal data that does not concern mammals and studies based on results from in vitro culture. Data have been grouped according to the studied pollutants in order to synthetize their impact on follicular development and follicular atresia and the molecular pathways involved. Ninety-seven studies appeared to be eligible and were included in the present study, even though few directly address POI. Phthalates, bisphenol A, pesticides and tobacco were the most reported substances having a negative impact on ovarian function with an increased follicular depletion leading to an earlier age of menopause onset. These effects were found when exposure occured at different times throughout the lifetime from the prenatal to the adult period, possibly due to different mechanisms. The main mechanism seemed to be an increase in atresia of pre-antral follicles.

CONCLUSION

Environmental pollutants are probably a cause of POI. Health officials and the general public must be aware of this environmental effect in order to implement individual and global preventive actions.

Obesity, Persistent Organic Pollutants and Related Health Problems

The present review aims to delve into persistent organic pollutants (POPs) , as xenobiotics, in correlation to human health. POPs exhibit a group of common characteristics, including lipophilicity, persistence to decomposition and bioaccumulation in tissues. POPs have been thoroughly studied by former researchers, as they offer a particular interest in the elucidation of metabolic, endocrine and immune perturbation caused by their synergy with intracellular mechanisms. Herein particular focus is attributed to the relationship of POPs with obesity provocation. Obesity nowadays receives epidemic dimensions, as its prevalence elevates in an exponential degree. POPs-induced obesity rotates around interfering in metabolic and endocrinal procedures and interacting with peroxisome-proliferator and retinoic receptors. Moreover, polymorphisms in CYP gene families exert a negative result, as they incapacitate detoxification of POPs. Obesity could be deemed as a multidimensional condition, as various factors interact to lead to an obesogenic result. Therefore, concomitant disorders may occur, from mild to lethal, and get intensified due to POPs exposure. POPs exact function mechanisms remain rather enigmatic, thus further investigation should be prospectively performed, for a more lucid picture of this issue, and, consequently for the establishment of alternative solutions.

Effects of PCB 126 and PCB 153 on secretion of steroid hormones and mRNA expression of steroidogenic genes (STAR, HSD3B, CYP19A1) and estrogen receptors (ERα, ERβ) in prehierarchical chicken ovarian follicles

The objective of this study was to assess the in vitro effects of dioxin-like PCB 126 and non-dioxin-like PCB 153 on basal and ovine LH (oLH)-stimulated testosterone (T) and estradiol (E2) secretion and expression of steroidogenic genes (STAR, HSD3B and CYP19A1) and estrogen receptors α (ERα) and β (ERβ) in white (WF) and yellowish (YF) prehierarchical follicles of the hen ovary. Steroid concentrations in a medium and gene expression in follicles following 6h of exposition were determined by RIA and real-time qPCR, respectively. Both PCBs increased basal and oLH-stimulated T secretion by the WF follicles. PCB 126 reduced basal E2 secretion by the WF follicles. PCB 153 elevated but PCB 126 reduced oLH-stimulated E2 secretion by the prehierarchical follicles. PCB 126 increased basal STAR and HSD3B and reduced CYP19A1 mRNA expression in these follicles. PCB 153 increased basal expression of STAR and HSD3B in YF follicles, but diminished HSD3B mRNA levels in the WF. The studied PCBs had an opposite effect on basal and oLH-stimulated CYP19A1 mRNA expression in prehierarchical follicles. Both PCBs modulated basal and inhibited oLH-stimulated ERα and ERβ gene expression in the prehierarchical follicles. In conclusion, data of the current study demonstrate the congener-specific effects of PCBs on sex steroid secretion by prehierarchical follicles of the chicken ovary, which are at least partly related to STAR, HSD3B and CYP19A1 gene expression. It is suggested that PCBs, by influencing follicular steroidogenesis and expression of estrogen receptors, may impair development and selection of yellowish follicles to the preovulatory hierarchy.

Impact of prenatal and postnatal exposure to bisphenol A on female rats in a two generational study: Genotoxic and immunohistochemical implications

Environmental xenoestrogen contaminant bisphenol A (BPA), widely used as a monomer in the manufacture of epoxy, polycarbonate plastics and polystyrene resins. However, exposure to BPA has raised concerns, and the negative impacts of its exposure on reproduction have been controversial. The purpose of this work was directed to assess the potential adverse effects of BPA on dam rats and their first generation females in a comparative toxicological study. Fifteen pregnant female rats were classified into three equal groups; first group was orally administered corn oil and served as control (group1), second and third groups were orally administered BPA at dose levels of 50 and 200 mg/kg b.wt respectively (groups 2 & 3). The administration was carried out daily from zero day through the gestation period (21 days) until the last day of the lactation period (21days) and was extended after weaning for three months, in which female off springs of first generation (F1) of the three groups of dams were classified into; F1control group (group 4), F1 group treated with low dose of BPA (group 5) and F1 group treated with high dose of BPA (group 6) which continued in daily oral administration of BPA at the same previously mentioned doses for three months. The results elucidated a clear marked DNA fragmentation in the ovary of both dam and F1 female groups especially at higher examined concentration. Also, the data demonstrated a significant increase in the serum levels of GGT, ALP, glucose, total cholesterol, triglycerides, LDH and also in the serum level of estrogen hormone. Meanwhile, our study recorded a significant decrease in total protein, catalase, GST, HDL and FSH hormone in both treated dam and F1 female groups which was more significantly decreased in F1 female rats. Moreover, our experiment illustrated up-regulation in the immunoexpression of ERβ in ovary, uterus and liver of dam and F1 female groups. The histopathological investigation showed degeneration in the epithelial lining of ovarian follicles, submucosal leukocytic infiltration and increase in vaculation of hepatic cells with proliferation of kupffer cells. The lesions were more sever in groups 3 & 6 of both dam and their F1 females. Our data speculated that long- term exposure to BPA at 50 and 200 mg/kg.b.wt. depicted total genomic damage, significant alterations in liver enzymes, lipid profile, antioxidant enzymes and reproductive hormones with up-regulation in the expression of ERβ which were more significantly perturbed in group 3 and group 6 of both dam and F1 female rats.

THE USE OF PLASMAPHERESIS IN TREATMENT OF PATIENTS WITH INFERTILITY, PERITONEAL ENDOMETRIOSIS AND NAT2 GENE POLYMORPHISM

It is known that 30–40 % of patients with peritoneal endometriosis suffer from infertility. Half of the patients with endometriosis are identified point mutation in NAT2 – gene, which plays an important role in the acetylation of aromatic and heterocyclic amines, in the accumulation of endotoxins, activation of free radical oxidation, impaired microcirculation. These factors involve the use of methods of gemapheresis which have detoxification, the blood rheology corrective and immune corrective effects. The purpose of this study was to evaluate the efficacy of therapeutic plasma exchange in treatment of patients with peritoneal form of endometriosis, infertility and point mutations in the gene NAT2. The study included 140 patients with infertility, peritoneal form of endometriosis and point mutations in the gene NAT2. All patients are performed laparoscopy, coagulation foci of endometriosis. In the following 93 (66.4 %) patients were treated with a the course of therapeutic plasmapheresis using the apparatus «PCS-2» with the removal of 20–25 % the volume of circulating plasma with replacement plasma of crystalloid and colloid solutions. Before treatment were shown the signs of endotoxemia, activation of oxidative stress. After treatment with the use of plasmapheresis was revealed the significant reduction of endogenous intoxication parameters and oxidative stress. Also is noted the increase in the pregnancy rate, both independently and in IVF programs, especially during the first 3 months after treatment. The findings suggest that the efficiency of the proposed comprehensive treatment techniques (laparoscopy and subsequent course of therapeutic plasmapheresis) of patients with peritoneal endometriosis and infertility and with point mutations in the gene NAT2. The use of plasmapheresis is pathogenetically justified in patients of the studied group.

Effect-based assessment of persistent organic pollutant and pesticide dumpsite using mammalian CALUX reporter cell lines

A combined chemical and biological analysis of samples from a major obsolete pesticide and persistent organic pollutant (POP) dumpsite in Northern Tajikistan was carried out. The chemical analytical screening focused on a range of prioritized compounds and compounds known to be present locally. Since chemical analytics does not allow measurements of hazards in complex mixtures, we tested the use of a novel effect-based approach using a panel of quantitative high-throughput CALUX reporter assays measuring distinct biological effects relevant in hazard assessment. Assays were included for assessing effects related to estrogen, androgen, and progestin signaling, aryl hydrocarbon receptor-mediated signaling, AP1 signaling, genotoxicity, oxidative stress, chemical hypoxia, and ER stress. With this panel of assays, we first quantified the biological activities of the individual chemicals measured in chemical analytics. Next, we calculated the expected sum activity by these chemicals in the samples of the pesticide dump site and compared the results with the measured CALUX bioactivity of the total extracts of these samples. The results showed that particularly endocrine disruption-related effects were common among the samples. This was consistent with the toxicological profiles of the individual chemicals that dominated these samples. However, large discrepancies between chemical and biological analysis were found in a sample from a burn place present in this site, with biological activities that could not be explained by chemical analysis. This is likely to be caused by toxic combustion products or by spills of compounds that were not targeted in the chemical analysis.

Bisphenol-A and Female Infertility: A Possible Role of Gene-Environment Interactions

Background: Bisphenol-A (BPA) is widely used and ubiquitous in the environment. Animal studies indicate that BPA affects reproduction, however, the gene-environment interaction mechanism(s) involved in this association remains unclear. We performed a literature review to summarize the evidence on this topic. Methods: A comprehensive search was conducted in PubMed using as keywords BPA, gene, infertility and female reproduction. Full-text articles in both human and animals published in English prior to December 2014 were selected. Results: Evidence shows that BPA can interfere with endocrine function of hypothalamic-pituitary axis, such as by changing gonadotropin-releasing hormones (GnRH) secretion in hypothalamus and promoting pituitary proliferation. Such actions affect puberty, ovulation and may even result in infertility. Ovary, uterus and other reproductive organs are also targets of BPA. BPA exposure impairs the structure and functions of female reproductive system in different times of life cycle and may contribute to infertility. Both epidemiological and experimental evidences demonstrate that BPA affects reproduction-related gene expression and epigenetic modification that are closely associated with infertility. The detrimental effects on reproduction may be lifelong and transgenerational. Conclusions: Evidence on gene-environment interactions, especially from human studies, is still limited. Further research on this topic is warranted.

Association of serum levels of typical organic pollutants with polycystic ovary syndrome (PCOS): a case-control study

STUDY QUESTION

Is polycystic ovary syndrome (PCOS) associated with increased serum levels of typical organic pollutants?

SUMMARY ANSWER

PCOS in Han females from Northern China was significantly associated with elevated serum levels of pollutants, including polychlorinated biphenyls (PCBs), organochlorine pesticides and polycyclic aromatic hydrocarbons (PAHs).

WHAT IS KNOWN ALREADY

PCOS is arguably the most common endocrinopathy in females of reproductive age. The etiology of PCOS is thought to be multifactorial.

STUDY DESIGN, SIZE, DURATION

This was a preliminary case-control study undertaken at the Division of Reproductive Center, Peking University Third Hospital. Fifty participants affected by PCOS and 30 normal controls were recruited between August and October 2012 from Northern China. All participants were Han women.

PARTICIPANTS/MATERIALS, SETTING, METHODS

PCOS participants were diagnosed according to the 2003 Rotterdam criteria. The control participants were non-pregnant females unable to conceive solely due to male azoospermia. Serum levels of a wide range of organic pollutants, including PCBs, organochlorine pesticides, PAHs and more than 20 phenolic pollutants, were analyzed using gas chromatographic mass spectrometry.

MAIN RESULTS AND THE ROLE OF CHANCE

Serum levels of PCBs, pesticides and PAHs were significantly higher in the PCOS group than the control group. Concentrations of PCBs, p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and PAHs in serum above median levels were associated with PCOS with odds ratios of 3.81 [95% confidence interval (CI), 1.45-10.0], 4.89 (95% CI, 1.81-13.2) and 2.39 (95% CI, 0.94-6.05), respectively. Partial least-squares-discriminant analysis (PLS-DA) confirmed that serum levels of organic pollutants were associated with PCOS, especially for p,p'-DDE and PCBs.

LIMITATIONS, REASONS FOR CAUTION

Some other possible covariates (e.g. dietary and income) were missed in this study, although education and occupation have been considered as an indicator of personal income. The PLS-DA model allowed a quasi-exposome analysis with over 60 kinds of typical organic pollutants; however, the possibility of other pollutants involved in the PCOS still could not be excluded.

WIDER IMPLICATIONS OF THE FINDINGS

Our study identified that bodily retention of environmental organic pollutants-including PCBs, pesticides (especially p,p'-DDE) and PAHs-was associated with PCOS.

STUDY FUNDING/COMPETING INTERESTS

This research was supported by the Ministry of Science and Technology of China Grants (973 program; 2014CB943203 and 2015CB553401), National Natural Science Foundation of China (21322705, 21190051, 41121004 and 81170538), National Key Technology R&D Program in the Twelve Five-Year Plan (2012BAI32B01) and the Collaborative Innovation Center for Regional Environmental Quality. There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

None. This is not a clinical trial.

Phlebotomy treatment for elimination of perfluoroalkyl acids in a highly exposed family: a retrospective case-series

BACKGROUND

Perfluoroalkyl acids (PFAAs) are a family of commonly used synthetic chemicals that have become widespread environmental contaminants. In human serum, perfluorohexane sulfonate (PFHxS), perflurooctane sulfonate (PFOS), and perfluorooctanoate (PFOA) are most frequently detected, in part owing to their long elimination half-lives of between 3.8 yrs (PFOA) and 8.5 yrs (PFHxS). These PFAAs also cross the placenta and have been associated with developmental toxicity, and some are considered likely human carcinogens. Interventions to eliminate PFAAs in highly contaminated individuals would reduce future health risks, but minimal research has been conducted on methods to facilitate accelerated human clearance of these persistent substances.

METHODS

Six patients with elevated serum concentrations from a single family were treated by intermittent phlebotomy over a 4-5 year period at intervals similar to, or less frequent than what is done for routine blood donation at Canadian Blood Services. The apparent elimination half-life (HLapp) for PFHxS, PFOS, and PFOA in this treated population was calculated in each patient and compared to the intrinsic elimination half-lives (HLin) from a literature reference population of untreated fluorochemical manufacturing plant retirees (n = 26, age >55 yrs).

RESULTS

For all three PFAAs monitored during phlebotomy, HLapp in each of the family members (except the mother, who had a low rate of venesection) was significantly shorter than the geometric mean HL measured in the reference population, and in some cases were even shorter compared to the fastest eliminator in the reference population.

CONCLUSION

This study suggests significantly accelerated PFAA clearance with regular phlebotomy treatment, but the small sample size and the lack of controls in this clinical intervention precludes drawing firm conclusions. Given the minimal risks of intermittent phlebotomy, this may be an effective and safe clinical intervention to diminish the body burden of PFAAs in highly exposed people.

Bisphenol A and the female reproductive tract: an overview of recent laboratory evidence and epidemiological studies

Bisphenol A (BPA) is a high production volume monomer used for making a wide variety of polycarbonate plastics and resins. A large body of evidence links BPA to endocrine disruption in laboratory animals, and a growing number of epidemiological studies support a link with health disorders in humans. The aim of this review is to summarize the recent experimental studies describing the effects and mechanisms of BPA on the female genital tract and to compare them to the current knowledge regarding the impact of BPA impact on female reproductive health. In particular, BPA has been correlated with alterations in hypothalamic-pituitary hormonal production, reduced oocyte quality due to perinatal and adulthood exposure, defective uterine receptivity and the pathogenesis of polycystic ovary syndrome. Researchers have reported conflicting results regarding the effect of BPA on premature puberty and endometriosis development. Experimental studies suggest that BPA's mechanism of action is related to life stage and that its effect on the female reproductive system may involve agonism with estrogen nuclear receptors as well as other mechanisms (steroid biosynthesis inhibition). Notwithstanding uncertainties and knowledge gaps, the available evidence should be seen as a sufficient grounds to take precautionary actions against excess exposure to BPA.

Zebrafish (Danio rerio) as a possible bioindicator of epigenetic factors present in drinking water that may affect reproductive function: is chorion an issue?

Emerging organic contaminants have been monitored in stream waters, raw and finished waters and wastewater effluents. Most of these contaminants, such as epigenetic substances, have been detected at very low levels. Unfortunately, their complete monitoring and/or removal are very difficult, given the increasing presence of new contaminants and due to analytical and economic considerations. For this reason, bioindicators are used as an alternative to monitor their presence. To this end, zebrafish is being used to assess certain contaminants in water quality studies. As our long-term aim is to determine if zebrafish (Danio rerio) can be used to detect environmental epigenetic factors in drinking waters with effects on human reproduction, an initial question is whether the chorion could interfere with the possible action of epigenetic factors in two reproductive events: genital ridge formation and migration of the primordial germ cells (PGCs) to these genital ridges. In the first experiment, we attempted to partially degrade the chorion of mid blastula transition (MBT) embryos with pronase, with acceptable survival rates at 5 days post fertilisation (dpf), with the group exposed for 15 min giving the best survival results. As denuded early embryos require a specific culture medium, in the next experiment embryo survival was evaluated when they were cultured up to 5 dpf in drinking waters from six different sources. Results showed a negative effect on embryo survival at 5 dpf from several waters but not in others, thus distorting the survival outcomes. These results suggest using embryos with the chorion intact from the outset when drinking waters from different sources are to be tested.

Urinary bisphenol A, phthalates, and couple fecundity: the Longitudinal Investigation of Fertility and the Environment (LIFE) Study

OBJECTIVE

To assess the relationship between environmental chemicals and couple fecundity or time to pregnancy (TTP).

DESIGN

Prospective cohort.

SETTING

Communities of targeted populations with reported exposure.

PATIENT(S)

501 couples recruited upon discontinuing contraception to become pregnant, 2005-2009.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Fecundability odds ratios (FORs) and 95% confidence intervals (CIs) estimated for each partner's chemical concentrations adjusted for age, body mass index, cotinine, creatinine, and research site while accounting for time off contraception.

RESULT(S)

Couples completed interviews and anthropometric assessments and provided the urine specimens for quantification of bisphenol A (BPA) and 14 phthalate metabolites, which were measured using high-performance liquid chromatography with electrospray triple-quadrupole mass spectrometer. Women recorded menstruation and pregnancy test results in daily journals. Couples were evaluated until a positive human-chorionic gonadotropin pregnancy test or 12 cycles without pregnancy. Neither female nor male BPA concentration was associated with TTP (FOR 0.98; 95% CI, 0.86, 1.13 and FOR 1.04; 95% CI, 0.91, 1.18, respectively). Men's urinary concentrations of monomethyl, mono-n-butyl, and monobenzyl phthalates were associated with a longer TTP (FOR 0.80; 95% CI, 0.70, 0.93; FOR 0.82, 95% CI, 0.70, 0.97; and FOR 0.77, 95% CI, 0.65 0.92, respectively).

CONCLUSION(S)

Select male but not female phthalate exposures were associated with an approximately 20% reduction in fecundity, underscoring the importance of assessing both partners' exposure to minimize erroneous conclusions.

Prenatal exposure to chromium induces early reproductive senescence by increasing germ cell apoptosis and advancing germ cell cyst breakdown in the F1 offspring

Hexavalent chromium (CrVI), one of the more toxic heavy metals, is widely used in more than 50 industries such as chrome plating, welding, wood processing and tanneries. As one of the world's leading producers of chromium compounds, the U.S. is facing growing challenges in protecting human health against multiple adverse effects of CrVI. CrVI is rapidly converted to CrIII intracellularly, and can induce apoptosis through different mechanisms. Our previous studies demonstrated postnatal exposure to CrVI results in a delay or arrest in follicle development and puberty. Pregnant rats were treated with 25 ppm potassium dichromate (CrVI) from gestational day (GD) 9.5 to 14.5 through drinking water, placentae were removed on GD 20, and total Cr was estimated in the placentae; ovaries were removed from the F1 offspring on postnatal day (PND)-1 and various analyses were performed. Our results show that gestational exposure to CrVI resulted in (i) increased Cr concentration in the placenta, (ii) increased germ cell apoptosis by up-regulating p53/p27-Bax-caspase-3 proteins and by increasing p53-SOD-2 co-localization; (iii) accelerated germ cell cyst (GCC) breakdown; (iv) advanced primordial follicle assembly and primary follicle transition and (v) down regulation of p-AKT, p-ERK and XIAP. As a result of the above events, CrVI induced early reproductive senescence and decrease in litter size in F1 female progeny.

Chronic exposure of mice to environmental endocrine-disrupting chemicals disturbs their energy metabolism

We evaluated the effects of a 20-week chronic exposure of mice to a low dose of cypermethrin (CYP), atrazine (ATZ) and 17α-ethynyestradiol (EE2) on energy metabolism. Here, male mice were exposed to 50 μg/kg BW/day CYP, 100 μg/kg BW/day ATZ or 1 μg/kg BW/day EE2 supplied in their drinking water for 20 weeks. During the exposure, mice were fed a high energy diet (HD). The bodyweights were not significantly affected by chronic exposure to EDCs, while the serum-free fatty acids (FFA) levels, hepatic lipid accumulation and triacylglycerol (TG) contents increased significantly in the ATZ- and CYP-HD groups. To determine the mechanism involved, we determined the expression levels of the genes in the glucose and fat metabolism pathways in the liver and adipose tissue. The results showed that chronic exposure to ATZ and CYP increased the mRNA levels of a number of key genes involved in both the de novo FFA synthesis pathway and the transport of FFA from blood. The increased amount of FFA was partially consumed as energy through β-oxidation in the mitochondria. Some of the FFA was used to synthesize TG in the liver by up-regulating primary genes, which resulted in increased TG levels and lipid accumulation. The results indicate that chronic exposure to EDCs has the potential to cause energy metabolic dysregulation and hepatotoxicity in mice.