A research synthesis of humans, animals, and environmental compartments exposed to PFAS: A systematic evidence map and bibliometric analysis of secondary literature

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are a class of widely used anthropogenic chemicals. Concerns regarding their persistence and potential adverse effects have led to multiple secondary research publications. Here, we aim to assess the resulting evidence base in the systematic secondary literature by examining research gaps, evaluating the quality of reviews, and exploring interdisciplinary connections.

METHODS

This study employed a systematic evidence-mapping approach to assess the secondary literature on the biological, environmental, and medical aspects of exposure to 35 fluorinated compounds. The inclusion criteria encompassed systematic reviews published in peer-reviewed journals, pre-prints, and theses. Comprehensive searches across electronic databases and grey literature identified relevant reviews. Data extraction and synthesis involved mapping literature content and narrative descriptions. We employed a modified version of the AMSTAR2 checklist to evaluate the methodological rigour of the reviews. A bibliometric data analysis uncovered patterns and trends in the academic literature. A research protocol for this study was previously pre-registered (osf.io/2tpn8) and published (Vendl et al., Environment International 158 (2022) 106973). The database is freely accessible through the interactive and user-friendly web application of this systematic evidence map at https://hi-this-is-lorenzo.shinyapps.io/PFAS_SEM_Shiny_App/.

RESULTS

Our map includes a total of 175 systematic reviews. Over the years, there has been a steady increase in the annual number of publications, with a notable surge in 2021. Most reviews focused on human exposure, whereas environmental and animal-related reviews were fewer and often lacked a rigorous systematic approach to literature search and screening. Review outcomes were predominantly associated with human health, particularly with reproductive and children's developmental health. Animal reviews primarily focused on studies conducted in controlled laboratory settings, and wildlife reviews were characterised by an over-representation of birds and fish species. Recent reviews increasingly incorporated quantitative synthesis methodologies. The methodological strengths of the reviews included detailed descriptions of study selection processes and disclosure of potential conflicts of interest. However, weaknesses were observed in the critical lack of detail in reporting methods. A bibliometric analysis revealed that the most productive authors collaborate within their own country, leading to limited and clustered international collaborations.

CONCLUSIONS

In this overview of the available systematic secondary literature, we map literature content, assess reviews' methodological quality, highlight data gaps, and draw research network clusters. We aim to facilitate literature reviews, guide future research initiatives, and enhance opportunities for cross-country collaboration. Furthermore, we discuss how this systematic evidence map and its publicly available database benefit scientists, regulatory agencies, and other stakeholders by providing access to current systematic secondary literature on PFAS exposure.

Bisphenol A promotes cell death in healthy respiratory system cells through inhibition of cell proliferation and induction of G2/M cell cycle arrest

Bisphenol A (BPA) is a substance that can harm the environment and human health by interfering with the normal functioning of the body's hormonal system. It is commonly found in various plastic-based products such as cosmetics, canned foods, beverage containers, and medical equipment and as well as it can also be absorbed by inhalation. There have been limited studies on the effects of BPA on lung fibroblasts, and it is still unclear how high levels of BPA can impact respiratory system cells, particularly the lungs and trachea. In this research, we aimed to investigate the cell cycle disruption potential of BPA on respiratory system cells by examining healthy trachea and lung cells together for the first time. The findings indicated that BPA exposure can alter the healthy cells' morphology, leading to reduced cellular viability that has been assessed by MTT and SRB assays. BPA treatment was able to activate caspase3 as expected, which could cause apoptosis in treated cells. Although the highest dose of BPA did not increase the apoptotic rate of rat trachea cells, it remarkably caused them to become necrotic (52.12%). In addition to quantifying the induction of apoptosis and necrosis by BPA, cell cycle profiles were also determined using flow cytometry. Thereby, BPA treatment unexpectedly inhibited the cell cycle's progression by causing G2/M cell cycle arrest in both lung and tracheal cells, which hindered cell proliferation. The findings of the study suggested that exposure to BPA could lead to serious respiratory problems, even respiratory tract cancers via alterations in the cell cycle.

Evaluation of Lipids and Lipid-Related Transcripts in Human and Ovine Theca Cells and an in Vitro Mouse Model Exposed to the Obesogen Chemical Tributyltin

BACKGROUND

Exposure to obesogenic chemicals has been reported to result in enhanced adipogenesis, higher adipose tissue accumulation, and reduced ovarian hormonal synthesis and follicular function. We have reported that organotins [tributyltin (TBT) and triphenyltin (TPT)] dysregulate cholesterol trafficking in ovarian theca cells, but, whether organotins also exert lipogenic effects on ovarian cells remains unexplored.

OBJECTIVE

We investigated if environmentally relevant exposures to organotins [TBT, TPT, or dibutyltin (DBT)] induce lipid dysregulation in ovarian theca cells and the role of the liver X receptor (LXR) in this effect. We also tested the effect of TBT on oocyte maturation and neutral lipid accumulation, and lipid-related transcript expression in cumulus cells and preimplantation embryos.

METHODS

Primary theca cell cultures derived from human and ovine ovaries were exposed to TBT, TPT, or DBT (1, 10, or 50   ng / ml ). The effect of these chemical exposures on neutral lipid accumulation, lipid abundance and composition, lipid homeostasis-related gene expression, and cytokine secretion was evaluated using liquid chromatography-mass spectrometry (LC-MS), inhibitor-based methods, cytokine secretion, and lipid ontology analyses. We also exposed murine cumulus-oocyte complexes to TBT and evaluated oocyte maturation, embryo development, and lipid homeostasis-related mRNA expression in cumulus cells and blastocysts.

RESULTS

Exposure to TBT resulted in higher intracellular neutral lipids in human and ovine primary theca cells. In ovine theca cells, this effect was dose-dependent, independent of cell stage, and partially mediated by LXR. DBT and TPT resulted in higher intracellular neutral lipids but to a lesser extent in comparison with TBT. More than 140 lipids and 9 cytokines were dysregulated in TBT-exposed human theca cells. Expression of genes involved in lipogenesis and fatty acid synthesis were higher in theca cells, as well as in cumulus cells and blastocysts exposed to TBT. However, TBT did not impact the rates of oocyte maturation or blastocyst development.

DISCUSSION

TBT induced dyslipidemia in primary human and ovine theca cells, which may be responsible for some of the TBT-induced fertility dysregulations reported in rodent models of TBT exposure. https://doi.org/10.1289/EHP13955.

Heavy Metals in Follicular Fluid Affect the Ultrastructure of the Human Mature Cumulus-Oocyte Complex

It is known that exposure to heavy metal such as lead (Pb) and cadmium (Cd) has several adverse effects, particularly on the human reproductive system. Pb and Cd have been associated with infertility in both men and women. In pregnant women, they have been associated with spontaneous abortion, preterm birth, and impairment of the development of the fetus. Since these heavy metals come from both natural and anthropogenic activities and their harmful effects have been observed even at low levels of exposure, exposure to them remains a public health issue, especially for the reproductive system. Given this, the present study aimed to investigate the potential reproductive effects of Pb and Cd levels in the follicular fluid (FF) of infertile women and non-smokers exposed to heavy metals for professional reasons or as a result of living in rural areas near landfills and waste disposal areas in order to correlate the intrafollicular presence of these metals with possible alterations in the ultrastructure of human cumulus-oocyte complexes (COCs), which are probably responsible for infertility. Blood and FF metals were measured using atomic absorption spectrometry. COCs corresponding to each FF analyzed were subjected to ultrastructural analyses using transmission electron microscopy. We demonstrated for the first time that intrafollicular levels of Pb (0.66 µg/dL-0.85 µg/dL) and Cd (0.26 µg/L-0.41 µg/L) could be associated with morphological alterations of both the oocyte and cumulus cells' (CCs) ultrastructure. Since blood Cd levels (0.54 µg/L-1.87 µg/L) were above the current reference values established by the guidelines of the Agency for Toxic Substances and Disease Registry (ATSDR) and the Environmental Protection Agency (EPA) (0.4 µg/L), whereas blood Pb levels (1.28 µg/dL-3.98 µg/dL) were below the ATSDR reference values (≤5 µg/dL), we believe that these alterations could be due especially to Cd, even if we cannot exclude a possible additional effect of Pb. Our results highlighted that oocytes were affected in maturation and quality, whereas CCs showed scarcely active steroidogenic elements. Regressing CCs, with cytoplasmic alterations, were also numerous. According to Cd's endocrine-disrupting activity, the poor steroidogenic activity of CCs might correlate with delayed oocyte cytoplasmic maturation. So, we conclude that levels of heavy metals in the blood and the FF might negatively affect fertilization, embryo development, and pregnancy, compromising oocyte competence in fertilization both directly and indirectly, impairing CC steroidogenic activity, and inducing CC apoptosis.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Endocrine Effect of Some Mycotoxins on Humans: A Clinical Review of the Ways to Mitigate the Action of Mycotoxins

Fungi such as Aspergillus spp. and Fusarium spp., which are commonly found in the environment, pose a serious global health problem. This study aims to present the results of epidemiological studies, including clinical cases, on the relationship between human exposure to some mycotoxins, especially zearalenone and aflatoxin, and the occurrence of reproductive disorders. In addition, examples of methods to reduce human exposure to mycotoxins are presented. In March 2023, various databases (PubMed, Google Scholar, EMBASE and Web of Science) were systematically searched using Google Chrome to identify studies evaluating the association between exposure to mycotoxins and the occurrence of complications related to impaired fertility or cancer incidence. The analysed data indicate that exposure to the evaluated mycotoxins is widespread and correlates strongly with precocious puberty, reduced fertility and increased cancer incidence in women and men worldwide. There is evidence to suggest that exposure to the Aspergillus mycotoxin aflatoxin (AF) during pregnancy can impair intrauterine foetal growth, promote neonatal jaundice and cause perinatal death and preterm birth. In contrast, exposure to the Fusarium mycotoxin zearalenone (ZEA) leads to precocious sexual development, infertility, the development of malformations and the development of breast cancer. Unfortunately, the development of methods (biological, chemical or physical) to completely eliminate exposure to mycotoxins has limited practical application. The threat to human health from mycotoxins is real and further research is needed to improve our knowledge and specific public health interventions.

Maternal pesticide exposure and risk of preterm birth: A systematic review and meta-analysis

BACKGROUND

Maternal pesticide exposure might be associated with adverse pregnancy outcomes through triggering inflammation and oxidative stress and disrupting endocrine functions. Yet the association between prenatal pesticide exposure and risk of preterm birth remains inconclusive.

OBJECTIVES

To conduct a systematic review and meta-analysis of human observational studies using the Office of Health Assessment and Translation (OHAT) framework to explore the association of per ten-fold increase of pesticide concentrations in maternal biological samples during pregnancy with risk of preterm birth and length of gestational age at birth.

DATA SOURCE

Five English (PubMed, Embase, Cochrane Library, Web of Science and Scopus) and 3 Chinese databases (China national knowledge infrastructure (CNKI), Wanfang Data, and Chinese Biomedical Literature Database (CBM)) were searched till Jan 18th, 2023.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS

To be included, pesticide exposure should be measured in maternal biological samples during pregnancy and in log-transformed forms. The primary outcome was preterm birth and the secondary outcome was gestational age at birth.

STUDY APPRAISAL, SYNTHESIS METHODS AND CONFIDENCE ASSESSMENT

Quality of studies was evaluated using OHAT Risk of Bias Tool. Evidence was quantitatively synthesized with Correlated and Hierarchical Effects (CHE) model. The confidence rating in the body of evidence was done using OHAT.

RESULTS

A total of 21 studies reported by 18 papers were included, with 7 studies for preterm birth and 19 for gestational age at birth. The meta-analysis found a ten-fold increase of pesticide concentrations was potentially associated with risk of preterm birth (pooled OR = 1.28; 95%CI: 0.93, 1.78) and shortened gestational age at birth (β = -0.10; 95%CI: -0.21, 0.01). Sampling biospecimens in different trimesters was identified as a potential modifier in the association between pesticide exposure and length of gestational age (F = 2.77, P < 0.05). For studies that collected samples at any time during pregnancy, pesticide exposure was found to be associated with shortened length of gestational age (β = -0.43; 95%CI: -0.81, -0.06). The confidence rating in the body of evidence was "moderate" and "very low" for preterm birth and gestational age at birth, respectively.

CONCLUSION

Our result suggested moderate evidence of an association between pesticide exposure and higher risk of preterm birth. Yet more studies are still needed with larger sample size and careful considerations of confounders and accuracy of outcome measurements. Attention is also required on other pesticide compounds in addition to organochlorine and organophosphorus pesticides, and on windows of susceptibility.

Maternal exposure to dibutyl phthalate regulates MSH6 crotonylation to impair homologous recombination in fetal oocytes

Homologous recombination (HR) during early oogenesis repairs programmed double-strand breaks (DSBs) to ensure female fertility and offspring health. The exposure of fetal ovaries to endocrine disrupting chemicals (EDCs) can cause reproductive disorders in the adulthood. The EDC dibutyl phthalate (DBP) is widely distributed in flexible plastic products, leading to ubiquitous human exposure. Here, we report that maternal exposure to DBP caused gross aberrations in meiotic prophase I of fetal oocytes, including delayed progression, impaired DNA damage response, uncoupled localization of DMC1 and RAD51, and decreased HR. However, programmed DSBs were efficiently repaired. DBP exposure negatively regulated lysine crotonylation (Kcr) of MSH6. Similar meiotic defects were observed in fetal ovaries with targeted disruption of Msh6, and mutation of K544cr of MSH6 impaired its association with Ku70, thereby promoting non-homologous end joining (NHEJ) and inhibiting HR. Unlike mature F1 females, F2 female mice exhibited premature follicular activation, precocious puberty, and anxiety-like behaviors. Therefore, DBP can influence early meiotic events, and Kcr of MSH6 may regulate preferential induction of HR or NHEJ for DNA repair during meiosis.

Environmental factors affecting pregnancy outcomes

INTRODUCTION

Pregnancy represents a fragile period in the life of a woman, vulnerable to hazardous environmental substances which might affect maternal and fetal metabolism. The possible influence of environmental factors, including endocrine disrupting chemicals (EDCs), upon the mother and the fetus before and/or during pregnancy might be associated directly and/or indirectly to deleterious pregnancy outcomes. Because the existence of such associations would be, to our view, of major importance to the scientific community, their investigation is the scope of this critical review.

METHODS

This critical review includes in vivo animal and human studies regarding the role of environmental factors, including EDCs, on pregnancy outcomes complying with the SANRA (a scale for the quality assessment of narrative review articles) questions for narrative reviews. Studies were identified by searching the MEDLINE (PubMed and PubMed Central), the Cochrane library and the Google Scholar databases till October 2022 with the combinations of the appropriate key words (detailed environmental factors including EDCs AND detailed negative pregnancy outcomes) as well as by scanning references from already included articles and relevant reviews manually. Because environmental factors and EDCs have been associated to epigenetic alterations, special care has been given to EDC-induced transgenerational effects on pregnancy outcomes.

RESULTS

The existing evidence suggests positive associations between specific environmental factors and negative pregnancy outcomes such as ectopic pregnancies, pregnancy losses, gestational diabetes, hypertensive disorders of pregnancy, preterm births, birth defects, intrauterine growth restriction, and small or large for gestational age babies.

CONCLUSION

Environmental factors and EDCs may have a catalytic effect on the course and the outcomes of pregnancy.

Environmental and occupational factors and higher risk of couple infertility: a systematic review study

Background

Infertility is a global health problem that represents an increasing trend due to new lifestyles following technological advances since individuals are facing more risk factors than before. The present systematic review study aimed to investigate the impact of environmental and occupational factors on reproductive parameters and increased risk of couple infertility.

Main body

Scopus, PubMed, SID, and Web of Science databases were searched for the available observational (i.e., cohort, case-control, and cross-sectional) systematic review, meta-analysis, and clinical trial studies between 2007 and 2019. To this end, keywords such as ‘Environmental exposure’, ‘Occupational exposure’, ‘Environmental pollutants’, ‘Environmental pollution’, ‘Couple infertility’, ‘Sterility’, and ‘Sub-fertility’ were used. The retrieved investigations examined the impact of environmental and occupational risk factors on reproductive indices and increased infertility risk. Totally, 66 out of 9519 papers were evaluated after considering the inclusion and exclusion criteria. The reported risk factors in the reviewed studies were heavy metals, cigarette smoking, and exposure to chemicals through consumer goods, urban life, and proximity to main roads. In addition, occupational factors included heavy physical activity, prolonged sitting, exposure to a hot environment, contact with formaldehyde, pesticides, insecticides, mechanical vibration, and contact with ionizing radiation, all of which affected the reproductive parameters. However, some researchers found no significant associations in this regard.

Short conclusion

In general, individuals with known impairments in reproductive parameters were more exposed to risk factors. Nonetheless, more studies are needed to determine the risk of infertility in the population.

Perfluorooctane Sulfonate Induces Dysfunction of Human Umbilical Vein Endothelial Cells via Ferroptosis Pathway

(1) Background: Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant, and it is receiving increasing attention regarding its human health risks due to its extensive use. Endothelial dysfunction is a mark of cardiovascular disease, but the basic mechanism of PFOS-induced endothelial dysfunction is still not fully understood. Ferroptosis is a newly defined regulatory cell death driven by cellular metabolism and iron-dependent lipid peroxidation. Although ferroptosis has been shown to be involved in the pathogenesis of cardiovascular diseases, the involvement of ferroptosis in the pathogenesis of endothelial dysfunction caused by PFOS remains unclear. (2) Purpose: To explore the role of ferroptosis in the dysfunction of endothelial cells and underlying mechanisms. (3) Methods: Human umbilical vein endothelial cells (HUVECs) were exposed to PFOS or PFOS and Fer-1. The viability, morphology change under electronic microscope, lipid-reactive oxygen species (lipid-ROS), and production of nitric oxide (NO) were determined. The expression of glutathione peroxidase 4(GPX4), ferritin heavy chain protein 1 (FTH1), heme oxygenase 1 (HO-1) and Acyl-CoA synthetase long-chain family member 4 (ACSL4) were analyzed via Western blot analysis. (4) Results: PFOS was shown to cause a decrease in viability and morphological changes of mitochondria, and well as an increase in lipid droplets. The expression of GPX4, FTH1 and HO-1 was decreased, and that of ACSL4 was increased after exposure to PFOS. In addition to the above-mentioned ferroptosis-related manifestations, there was also a reduction in NO content. (5) Conclusions: PFOS induces ferroptosis by regulating the GPX4 and ACSL4 pathways, which leads to HUVEC dysfunction.

Chronic exposure to propylparaben at the humanly relevant dose triggers ovarian aging in adult mice

Parabens, a type of endocrine-disrupting chemicals, are widely used as antibacterial preservatives in food and cosmetics in daily life. Paraben exposure has gained particular attention in the past decades, owing to its harmful effects on reproductive function. Whether low-dose paraben exposure may cause ovarian damage has been ignored recently. Here, we investigated the effects of chronic low-dose propylparaben (PrPB) exposure on ovarian function. Female C57BL/6J mice were exposed to PrPB at a humanly relevant dose for 8 months. Our results showed that chronic exposure to PrPB at a humanly relevant dose significantly altered the estrus cycle, hormone levels, and ovarian reserve, accelerating ovarian aging in adult mice. These effects are accompanied by oxidative stress enrichment, leading to steroidogenesis dysfunction and acceleration of primordial follicle recruitment. Notably, melatonin supplementation has been shown to protect against PrPB-induced steroidogenesis dysfunction in granulosa cells. Here, we report that daily chronic PrPB exposure may contribute to ovarian aging by altering oxidative stress-mediated JNK and PI3K-AKT signaling regulation, and that melatonin may serve as a pharmaceutical candidate for PrPB-associated ovarian dysfunction.

Developmental Exposure to Endocrine Disrupting Chemicals and Its Impact on Cardio-Metabolic-Renal Health

Developmental origin of health and disease postulates that the footprints of early life exposure are followed as an endowment of risk for adult diseases. Epidemiological and experimental evidence suggest that an adverse fetal environment can affect the health of offspring throughout their lifetime. Exposure to endocrine disrupting chemicals (EDCs) during fetal development can affect the hormone system homeostasis, resulting in a broad spectrum of adverse health outcomes. In the present review, we have described the effect of prenatal EDCs exposure on cardio-metabolic-renal health, using the available epidemiological and experimental evidence. We also discuss the potential mechanisms of their action, which include epigenetic changes, hormonal imprinting, loss of energy homeostasis, and metabolic perturbations. The effect of prenatal EDCs exposure on cardio-metabolic-renal health, which is a complex condition of an altered biological landscape, can be further examined in the case of other environmental stressors with a similar mode of action.

Association between per- and polyfluoroalkyl substances and risk of gestational diabetes mellitus

BACKGROUND

Existing evidence suggests that perfluoroalkyl and polyfluoroalkyl substances (PFASs) exposure might contribute to the incidence of gestational diabetes mellitus (GDM). This study aimed to perform a meta-analysis to identify the association between PFAS and the risk of GDM.

METHODS

We systematically searched PubMed, Ovid, Cochrane Library, and Web of Science databases for appropriate articles about the association between PFASs exposure and the risk of GDM before September 28, 2020. Odds ratios (OR) with 95% confidence intervals (CIs) were summarized by Stata 16.0 through fixed effect models according to heterogeneity. We also carried out subgroup analyses by geographic location, blood sampling time of subjects, method of chemical analysis, study design, sample size, and sampling year. In addition, a sensitivity analysis was conducted to explore the robustness of the results.

RESULTS

A total of eight studies involving 5654 pregnant women were included in the meta-analysis. Perfluorooctanoic acid (PFOA) exposure was positively and significantly associated with the risk of GDM (OR = 1.27, 95% CI: 1.02-1.59). Exposure to other types of PFASs such as perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), perfluorononanoic acid (PFNA) was not statistically significantly associated with the risk of GDM with the pooled effect estimates of 0.97 (95% CI: 0.86-1.09), 1.03 (95% CI: 0.86-1.24), and 0.80 (95% CI: 0.55-1.16) respectively.

CONCLUSION

We conducted a meta-analysis to investigate the association between PFASs exposure and GDM and found that PFOA concentration was significantly associated with a higher risk of GDM, which is of great significance for the prevention and control of GDM in public health. Further studies are needed in order to establish causality and clarify the potential mechanism.

Machine Learning for Investigation on Endocrine-Disrupting Chemicals with Gestational Age and Delivery Time in a Longitudinal Cohort

Endocrine-disrupting chemicals (EDCs) are widespread environmental chemicals that are often considered as risk factors with weak activity on the hormone-dependent process of pregnancy. However, the adverse effects of EDCs in the body of pregnant women were underestimated. The interaction between dynamic concentration of EDCs and endogenous hormones (EHs) on gestational age and delivery time remains unclear. To define a temporal interaction between the EDCs and EHs during pregnancy, comprehensive, unbiased, and quantitative analyses of 33 EDCs and 14 EHs were performed for a longitudinal cohort with 2317 pregnant women. We developed a machine learning model with the dynamic concentration information of EDCs and EHs to predict gestational age with high accuracy in the longitudinal cohort of pregnant women. The optimal combination of EHs and EDCs can identify when labor occurs (time to delivery within two and four weeks, AUROC of 0.82). Our results revealed that the bisphenols and phthalates are more potent than partial EHs for gestational age or delivery time. This study represents the use of machine learning methods for quantitative analysis of pregnancy-related EDCs and EHs for understanding the EDCs' mixture effect on pregnancy with potential clinical utilities.

Urinary bisphenol A in women with polycystic ovary syndrome - a possible suppressive effect on steroidogenesis?

OBJECTIVES

There is a growing evidence indicating an impact of endocrine distrupting chemicals such as bisphenol A (BPA) on human reproduction. Its higher levels in serum or urine have been documented in women with polycystic ovary syndrome (PCOS), however the relationship to ovarian steroidogenesis remains unclear.Aim of the study was to compare urinary BPA (U-BPA) concentrations among PCOS women and control group. Second aim was to assess the relationship of U-BPA to ovarian steroidogenesis in the group with PCOS.

METHODS

Eighty six Caucasian women (age 28.5 ± 5.1 years) diagnosed with PCOS and 32 controls of age 24.9 ± 4.4 years were included in the study. Fasting blood samples were analyzed for biochemical parameters and steroid hormones. U-BPA was measured in the morning urine sample using high pressure liquid chromatography.

RESULTS

PCOS women had significantly higher U-BPA as compared with control group (p=0.0001). Those with high levels of U-BPA (U-BPA ≥2.14 ug/g creatinine) demonstrated higher serum insulin (p=0.029) and HOMA IR (p=0.037), lower serum estrone (p=0.05), estradiol (p=0.0126), FSH (p=0.0056), and FAI (p=0.0088), as compared with low-BPA group (U- BPA <2.14 ug/g creatinine). In PCOS women, U-BPA positively correlated with age (p=0.0026; R²=0.17), negatively with estradiol (p=0.0001, R²=0.5), testosterone (p=0.0078, R²=0.15), free-testosterone (p=0.0094, R²=0.12) and FAI (p=0.0003, R²=0.32), respectively.

CONCLUSIONS

PCOS women have significantly higher U-BPA concentrations than healthy controls. U-BPA positively correlates with age and negatively with ovarian steroid hormones suggesting a possible suppressive effect of bisphenol A on ovarian steroidogenesis.

The influence of phenolic environmental estrogen on the transcriptome of uterine leiomyoma cells: A whole transcriptome profiling-based analysis

OBJECTIVE

The study aimed to recognize potential molecular targets and signal pathways whereby phenolic environmental estrogen promotes the proliferation of uterine leiomyoma cells.

METHODS

Primary cultured cell lines of uterine leiomyoma were treated with 0.1% DMSO, 10.0μmol/L Bisphenol A (BPA), and 32.0μmol/L Nonylphenol (NP) for 48 h before RNA-seq was performed. Those genes affected by BPA and NP were identified. Then, Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and Protein-protein Interaction (PPI) analysis were performed. Quantitative real-time polymerase chain reaction (q-PCR) and western blot were used to verify the differentially expressed gene and protein.

RESULTS

Compared to with the control group, 739 differentially expressed genes were identified in both the BPA group and the NP group. GO enrichment analysis showed that the most enriched GO terms were connective tissue development and G1/S transition of mitotic cell cycle, and extracellular matrix. The results of KEGG enrichment analysis showed that differentially expressed mRNA were enriched mainly in three primary pathways, including environmental information processing, human diseases, and cellular processes. The cell cycle, PI3K-Akt signaling pathway are significantly enriched. The q-PCR and western blot verified the cell cycle associated genes and proteins were upregulated in both BPA group and NP group. Both BPA and NP activated the PI3K-AKT signaling pathway.

CONCLUSION

Phenolic environmental estrogens may promote the proliferation and cell cycle progression of uterine leiomyoma cells through rapid non-genomic ER signaling, which leads to disordered cell cycle regulation and accelerates the transition of the cell cycle from G0/G1 phase to S phase. In addition, as an external stimulant, phenolic estrogen promotes the upregulation of inflammatory factors in uterine leiomyomas.

Reproductive toxic potential of phthalate compounds - State of art review

Phthalates are pervasive compounds, and due to the ubiquitous usage of phthalates, humans or even children are widely exposed to them. Since phthalates are not chemically bound to the plastic matrix, they can easily leach out to contaminate the peripheral environment. Various animal and human studies have raised vital health concern including developmental and reproductive toxicity of phthalate exposure. The present review is based upon the available literature on phthalates with respect to their reproductive toxic potential. Common reproductive effects such as declined fertility, reduced testis weight, variations in accessory sex organs and several female reproductive disorders appeared to be largely associated with the transitional phthalates. Among the higher molecular weight phthalates (≥ C7), di-isononyl phthalate (DINP) produces some minor effects on development of male reproductive tract and among low molecular weight phthalates (≤C3), di-methyl (DMP) and di-isobutyl (DIBP) phthalate produce some adverse effects on male reproductive system. Whereas transitional phthalates such as di-butyl phthalate, benzyl butyl phthalate, and di-(2-ethylhexyl) phthalate have shown adverse effects on female reproductive system. Owing to these, non-toxic alternatives to phthalates may be developed and use of phthalates could be rationalized as an important issue where human reproduction system is involved. Though, more epidemiological studies are needed to substantiate the reported findings on phthalates.

Effects of Bisphenol A Released From Composite Fillings on Reproductive Hormone Levels in Men

Objectives

Composite resins are the most preferred filling material because of their excellent aesthetic qualities. However, a filling material should also be biocompatible as well as aesthetic. The aim of this study was to determine the serum and saliva bisphenol-A (BPA) levels and to examine the effects of serum BPA on reproductive hormone levels after healthy men were treated with composite fillings.

Methods

Eighteen healthy males each received 2 composite restorations. Saliva and blood samples of subjects were collected before resin application and 1 day and 1, 3, and 5 weeks after the resin was applied. BPA amounts in samples were detected using high-performance liquid chromatography (HPLC). Serum gonadotropins, testosterone, sex hormone binding globulin, free androgen index, and oestrogen levels were measured with radioimmunological assay kits. Statistical analysis of data was made using Friedman, Wilcoxon signed ranks and Mann-Whitney U tests (α = 0.05).

Results

The amount of BPA released from composite resins over time was not significantly elevated in either saliva or serum (P > 0.5). In addition, serum BPA levels were significantly higher than saliva BPA levels for both composites (P < .05), but saliva and serum BPA levels were not statistically different when comparing the 2 composites (P > .05).

Conclusions

BPA from composite resins used in this study did not significantly alter serum hormone levels.

Developmental Programming: Physiological Impacts of Prenatal Melatonin Administration on Reproductive Capacity and Serum Triiodothyronine of Adult Female Offspring Rat Born to Moms Exposed to Bisphenol A During Pregnancy

Gestational bisphenol A (BPA) exposure induced multiple programmed diseases in the adult offsprings. Thus, this study targeted exploring the physiological impacts of melatonin (MEL) as a reprogramming strategy against in utero BPA exposure on reproductive capacity of adult F1 female rat offspring. Forty adult pregnant albino female rats were divided equally into 5 groups (n = 8): group I (control), group II (low-dose BPA; 25 μg BPA/kg B.w.t.), group III (low-dose BPA + 10 mg MEL/kg B.w.t.), group IV (high-dose BPA; 250 μg/kg B.w.t.), and group V (high-dose BPA + MEL). Treatments were given daily by subcutaneous (s/c) injection from the fourth day of pregnancy until full term. After delivery, female offspring were selected, and on postnatal day 60, adult offspring were examined for estrus regularity and then were sacrificed at estrus to collect blood and tissue samples. Findings clarified that in utero BPA exposure (both doses) increased significantly (P < 0.05) the ovarian weights and the serum levels of estrogen but decreased that of triiodothyronine (T3) compared to control groups. Significant increasing of serum malondialdehyde (MDA) and decreasing of total antioxidant capacity (TAC) were also detected. Both doses of BPA disturbed remarkably the estrus cycles and caused marked aberrations in ovarian and uterine tissues. Interestingly, prenatal MEL co-treatment with BPA mitigated significantly all of these degenerative changes. Thus, this study first demonstrated that prenatal MEL therapy could be used as a potent reprogramming intervention against BPA-induced reproductive disorders in the adult F1 female rat offspring.

Association of bisphenol A with puberty timing: a meta-analysis

OBJECTIVES

The results of existing studies on bisphenol A (BPA) and puberty timing did not reach a consensus. Thereby we performed this meta-analytic study to explore the association between BPA exposure in urine and puberty timing.

METHODS

Meta-analysis of the pooled odds ratios (OR), prevalence ratios (PR) or hazards ratios (HR) with 95% confidence intervals (CI) were calculated and estimated using fixed-effects or random-effects models based on between-study heterogeneity.

RESULTS

A total of 10 studies involving 5621 subjects were finally included. The meta-analysis showed that BPA exposure was weakly associated with thelarche (PR: 0.96, 95% CI: 0.93-0.99), while no association was found between BPA exposure and menarche (HR: 0.99, 95% CI: 0.89-1.12; OR: 1.02, 95% CI: 0.73-1.43), and pubarche (OR: 1.00, 95% CI: 0.79-1.26; PR: 1.00, 95% CI: 0.95-1.05).

CONCLUSIONS

There was no strong correlation between BPA exposure and puberty timing. Further studies with large sample sizes are needed to verify the relationship between BPA and puberty timing.

Di-(2-ethylhexyl) phthalate induced developmental abnormalities of the ovary in quail (Coturnix japonica) via disruption of the hypothalamic-pituitary-ovarian axis

An increasing number of epidemiologic studies show that women have a special exposure profile to phthalates, and the exposures have attracted attention regarding their potential health hazards. Here, we developed a model for studying the ovarian action of di-(2-ethylhexyl) phthalate (DEHP) and its major metabolite monoethylhexyl phthalate (MEHP). In vivo, treatment with DEHP (250, 500, and 1000 mg kg^-1) induced decreased thickness of ovarian granulosa cell layer and mitochondrial damage in quail, caused oxidative stress, interfered with the transcription of hypothalamic-pituitary-ovarian axis (HPOA) steroid hormone-related factors (increased transcription of StAR, 3β-HSD, P450scc, and LH and decreased transcription of 17β-HSD, P450arom, FSH, and ERβ), and blocked the secretion of steroid hormones (decreased FSH, E₂, and T levels and increased LH, P, and PRL levels). In vitro, granulosa cells were cultured with MEHP (50, 100, and 200 μM), activator of PPARγ (rosiglitazone, 50 μM), or antagonist of PPARγ (GW9662, 10 μM) for 24 h and gene and protein expression were analyzed by real time RT-PCR and western blot. Rosiglitazone, like MEHP, significantly decreased mRNA and protein levels of P450arom. Antagonist GW9662 partially blocked the suppression of P450arom by MEHP, suggesting that MEHP acts through PPARγ, but not exclusively. Our model shows that MEHP acts on granulosa cells in quail by stimulating PPARs, which leads to decreased gene and protein expression of P450arom. Therefore, the environmental endocrine disruptor DEHP and its major metabolite MEHP act through a receptor-mediated signaling pathway to inhibit the production of estradiol, interfere with the modulation of HPOA, suppress the synthesis of sex hormones, and cause sex hormone secretion disorders, resulting in severe toxicity in the female reproductive system. A framework for an adverse outcome pathway of DEHP/MEHP-induced ovarian toxicity was constructed, which can facilitate an improved understanding of the mechanism of female reproductive toxicity.

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) and their effects on the ovary

BACKGROUND

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are found widespread in drinking water, foods, food packaging materials and other consumer products. Several PFAS have been identified as endocrine-disrupting chemicals based on their ability to interfere with normal reproductive function and hormonal signalling. Experimental models and epidemiologic studies suggest that PFAS exposures target the ovary and represent major risks for women's health.

OBJECTIVE AND RATIONALE

This review summarises human population and toxicological studies on the association between PFAS exposure and ovarian function.

SEARCH METHODS

A comprehensive review was performed by searching PubMed. Search terms included an extensive list of PFAS and health terms ranging from general keywords (e.g. ovarian, reproductive, follicle, oocyte) to specific keywords (including menarche, menstrual cycle, menopause, primary ovarian insufficiency/premature ovarian failure, steroid hormones), based on the authors' knowledge of the topic and key terms.

OUTCOMES

Clinical evidence demonstrates the presence of PFAS in follicular fluid and their ability to pass through the blood-follicle barrier. Although some studies found no evidence associating PFAS exposure with disruption in ovarian function, numerous epidemiologic studies, mostly with cross-sectional study designs, have identified associations of higher PFAS exposure with later menarche, irregular menstrual cycles, longer cycle length, earlier age of menopause and reduced levels of oestrogens and androgens. Adverse effects of PFAS on ovarian folliculogenesis and steroidogenesis have been confirmed in experimental models. Based on laboratory research findings, PFAS could diminish ovarian reserve and reduce endogenous hormone synthesis through activating peroxisome proliferator-activated receptors, disrupting gap junction intercellular communication between oocyte and granulosa cells, inducing thyroid hormone deficiency, antagonising ovarian enzyme activities involved in ovarian steroidogenesis or inhibiting kisspeptin signalling in the hypothalamus.

WIDER IMPLICATIONS

The published literature supports associations between PFAS exposure and adverse reproductive outcomes; however, the evidence remains insufficient to infer a causal relationship between PFAS exposure and ovarian disorders. Thus, more research is warranted. PFAS are of significant concern because these chemicals are ubiquitous and persistent in the environment and in humans. Moreover, susceptible groups, such as foetuses and pregnant women, may be exposed to harmful combinations of chemicals that include PFAS. However, the role environmental exposures play in reproductive disorders has received little attention by the medical community. To better understand the potential risk of PFAS on human ovarian function, additional experimental studies using PFAS doses equivalent to the exposure levels found in the general human population and mixtures of compounds are required. Prospective investigations in human populations are also warranted to ensure the temporality of PFAS exposure and health endpoints and to minimise the possibility of reverse causality.

Assessment of environmental knowledge and needs among assisted reproductive technology professionals

PURPOSE

Exposure to environmental contaminants is to be taken into account in preventive healthcare in general and particularly in the field of reproduction according to the increasing amount of evidence data being published. The aim of this study is to evaluate the practices and interest in and basic knowledge of environmental health, by the professionals of the ART process: doctor, embryologist, and nurses.

METHODS

Survey among 12 Belgian assisted reproductive technology (ART) centers.

RESULTS

The response rate was 67%: 43.5% of the ART professionals do bring up the topic of environmental contaminants with their patients, without significant differences among types of professionals. Ninety percent of respondents believe that it would be useful, and 63% mention their lack of knowledge and the absence of solutions (20.5%) to explain their inaction. Lack of knowledge is much greater for nurses respectively (85%) compared with doctors (52%) and biologists (54%). The most popular means toward improving their knowledge is scientific seminars (69%). The questionnaire to evaluate the health professional knowledge gives 56% of adequate replies. The topic concerning eating habits obtains a very bad score of knowledge. When looking at exposure to occupational risks, 75% of the answers were correct.

CONCLUSIONS

The place of ART before conception makes it an ideal entry point for the prevention of environmental hazards. This study corroborates the previous observations which underline the importance to reinforce the concepts of environmental health in the initial and continuous training of health professionals.

Birth Cohorts in Highly Contaminated Sites: A Tool for Monitoring the Relationships Between Environmental Pollutants and Children's Health

Industrial areas are characterized by the dispersion of environmental stressors that could possibly have long-term detrimental effects on both human health and the environment. Environmental contamination has been indicated to be one of the major risks for reproductive health. In this context, the effects of environmental pollution on pregnant women living in heavily polluted areas is of special interest. In fact, fetal development is a crucial phase due to the dynamic interaction between the maternal/external environments and the developing organs and tissues. Moreover, following Barker's postulate of the intrauterine origin of health and disease, the events occurring in this time window could affect future health. Birth cohorts provide the most suitable design for assessing the association between early-life and possible long-term health outcomes in highly contaminated sites. By providing an assessment of the early life environment throughout the collection of biological samples, birth cohorts offer the opportunity to study in-depth several possible confounders and outcomes by means of questionnaires and follow-ups based on clinical evaluations and bio-specimen samplings. The exposome comprises the totality of exposures from conception onwards; the birth cohort approach allows the integration of the exposures as a whole, including those related to socioeconomic status, with "omics" data from biological samples collected at birth and throughout life. In the characterization of the "fetal exposome," the placenta represents a highly informative and scarcely considered organ. For this purpose, the "Neonatal Environment and Health Outcomes" (NEHO) birth cohort has been established by enrolling pregnant women residing in contaminated sites and in surrounding areas.

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.

Racial disparity in maternal phthalates exposure; Association with racial disparity in fetal growth and birth outcomes

Experimental and observational data implicate phthalates as developmental toxicants. However, few data are available to assess the maternal risks of gestational exposure by race and infant sex. To begin to address this data gap, we characterized associations between maternal urinary phthalate metabolites and birth outcomes among African American and white mothers from a southeastern U.S. population. We enrolled pregnant African American (n = 152) and white (n = 158) women with singleton live births between 18 and 22 weeks gestation. We measured phthalate metabolites (mono-n-butyl phthalate (MBP), monoisobutyl phthalate (MiBP), monobenzyl phthalate (MBzP), mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), monoethyl phthalate (MEP), monomethyl phthalate (MMP), and the sums of DEHP (ΣDEHP) and DBP (ΣDBP) metabolites) in up to two gestational urine specimens from mothers, and evaluated confounder-adjusted associations per natural log unit greater concentration with birth weight for gestational age z-score, small for gestational age (SGA; <10th %tile), preterm birth (PTB; <37 weeks gestation), and low birth weight (LBW; <2500 g). We also tested for interactions by maternal race and infant sex. We found that lower z-scores were associated with greater MiBP (β = -0.28; 95% CI: -0.54, -0.02) and MMP (β = -0.30; 95% CI: -0.52, -0.09) concentrations, while MEP interacted with race (p = 0.04), indicating an association among whites (β = -0.14; 95% CI: -0.28, 0.001) but not among African Americans (β = 0.05; 95% CI = -0.09, 0.19). Greater MiBP (OR = 2.82; 95% CI: 1.21, 6.56) and MEOHP (OR = 2.80; 95% CI: 1.05, 7.42) were associated with an overall higher SGA risk, greater MEHP was associated with higher SGA risk (p = 0.10) in whites (OR = 3.26 95% CI: 0.64, 16.56) but not in African Americans (OR = 0.71 95% CI: 0.07, 7.17), and the associations for MiBP (p = 0.02) and ΣDBP (p = 0.02) varied by infant sex. We detected interactions for PTB in which African Americans were at higher risk than whites for greater MiBP (p = 0.08) and MEP (p = 0.02) although lower risk for greater MEHP (p = 0.09). Greater MEP was associated with an overall higher LBW risk (OR = 1.33; 95% CI: 0.95, 1.86), and males were at higher risk than females with greater MBP (p = 0.002), MiBP (p = 0.02), MBzP (p = 0.01), MEP (p = 0.002), MMP (p = 0.09), and ΣDBP (p = 0.01) concentrations. Overall, our results suggest that gestational phthalate exposure is associated with adverse maternal birth outcomes, and that the effects vary by maternal race and infant sex.

Prenatal exposure to PCBs and neurological and sexual/pubertal development from birth to adolescence

Several chemical compounds are resistant to degradation and end up in the food chain. One group of these chemicals is polychlorinated biphenyls (PCBs) which are used as flame retardants and plasticizers. Although PCBs were banned several decades ago, PCBs are still found in environmental media, including in the body of humans. PCBs are transferred from mother to fetus via the placenta during pregnancy. Considering that the prenatal period is a sensitive period during which essential developmental processes take place, exposure to environmental chemicals might have considerable and permanent consequences for outcomes in later life. The aim of this review is to provide an update on the latest insights on the effects of prenatal exposure to PCBs on neurological, sexual and pubertal development in children. We give an overview of recent literature, and discuss it in the light of the findings in a unique Dutch birth cohort, with data on both neurological and pubertal development into adolescence. The findings in the studies included in this review, together with the findings in the Dutch cohort, demonstrate that prenatal exposure to PCBs can interfere with normal child development, not only during the perinatal period, but up to and including adolescence. Higher prenatal exposure to PCBs was found to be both negatively and positively associated with neurodevelopmental outcomes. Regarding pubertal development, higher prenatal PCB exposure was found to be associated with more advanced pubertal development, also in the Dutch cohort, whereas other studies also found delayed pubertal development. These findings raise concern regarding the effects of man-made chemical compounds on child development. They further contribute to the awareness of how environmental chemical compounds can interfere with child development and negatively influence healthy ageing.

Early pregnancy exposure to endocrine disrupting chemical mixtures are associated with inflammatory changes in maternal and neonatal circulation

Endocrine disrupting chemicals (EDCs) are ubiquitous, and pregnancy is a sensitive window for toxicant exposure. EDCs may disrupt the maternal immune system, which may lead to poor pregnancy outcomes. Most studies investigate single EDCs, even though "real life" exposures do not occur in isolation. We tested the hypothesis that uniquely weighted mixtures of early pregnancy exposures are associated with distinct changes in the maternal and neonatal inflammasome. First trimester urine samples were tested for 12 phthalates, 12 phenols, and 17 metals in 56 women. Twelve cytokines were measured in first trimester and term maternal plasma, and in cord blood after delivery. Spearman correlations and linear regression were used to relate individual exposures with inflammatory cytokines. Linear regression was used to relate cytokine levels with gestational age and birth weight. Principal component analysis was used to assess the effect of weighted EDC mixtures on maternal and neonatal inflammation. Our results demonstrated that maternal and cord blood cytokines were differentially associated with (1) individual EDCs and (2) EDC mixtures. Several individual cytokines were positively associated with gestational age and birth weight. These observed associations between EDC mixtures and the pregnancy inflammasome may have clinical and public health implications for women of childbearing age.

Inhibitory effect of Bisphenol A on in vitro feline uterine contractions

Bisphenol A (BPA) is an environmental pollutant used as a plasticizer in the manufacture of many plastic products, such as packaging, containers, and water and beverage bottles. There are deleterious effects of BPA on metabolic, endocrine, nervous, and reproductive systems. This is the first study in which there was investigation of the in vitro effect of BPA on the spontaneous contractions of the cat uterus. The tubal uterine segments (1 cm) collected from queens in estrus were suspended in an isolated organ bath. Following tissue stabilization, spontaneous contractions were recorded for 10 min to constitute the control group. The effects of the solvent (alcohol) and BPA at different concentrations (1, 10, and 100 μM) on uterine contractions were subsequently evaluated at 10 min intervals in terms of frequency and mean amplitude variables. The ethanol vehicle did not alter the uterine contractions compared to the control group. All concentrations of BPA used in the study resulted in a reduction (P < 0.05) in amplitude of uterine contractions in a dose-dependent manner, while only the largest dose of BPA decreased the frequency of contractions (P < 0.05). In reproductive physiology, regular uterine contractions facilitate successful fertilization, migration, implantation, and maintenance of pregnancy, as well as fetus expulsion. The results of this study indicate BPA has an inhibitory effect on spontaneous contractions of the cat uterus. It is proposed that this suppressive effect of BPA on uterine contractions might lead to queen infertility.

Bisphenol S, a Bisphenol A alternative, impairs swine ovarian and adipose cell functions

The high-volume-produced plastic monomer Bisphenol A (BPA) has been in the spotlight in the last years because of its endocrine disruptor (ED) behavior, leading to disclosure of the association between the widespread human and wildlife exposure to BPA and reproductive, metabolic, and developmental disorders and hormone-dependent cancer onset. These evidences caused restrictions and prohibitions of BPA industrial uses and prompted investigation of harmless alternative compounds. Above all, several countries have substituted the parental analogue with Bisphenol S (BPS) in baby care product manufacturing, even if its structural homology to BPA suggests similar ED properties not yet completely ruled out. In light of this consideration, the aim of this in vitro study was to investigate the effect of BPS exposure (0.1, 1, and 10 μM for 48 h) on granulosa cells that are considered the prime ovarian targets of BPA as a "reproductive toxicant". Our data document that BPS inhibited E2 production, cell proliferation, and scavenging nonenzymatic activity (P < 0.05) while it significantly (P < 0.05) stimulated cell viability, superoxide (O₂^-) and nitric oxide (NO) production in cultured swine granulosa cells, a previously validated endocrine cell model for BPA. Evidence also exists that BPA and its analogues, as environmental lipophilic pollutants, are involved in the disruption of adipose tissue (AT) endocrine function, resulting in metabolic effects and thus in potential reproductive disorders. On this basis, our second purpose was the assessment of BPS effects on mesenchymal stromal cells (MSCs) isolated from porcine AT, taking into account MSCs viability and adipogenic differentiation, a process actually demonstrated to be largely affected by EDs. Our results show that BPS decreased (P < 0.001) cell viability of proliferating adipose stromal cells. Taken as a whole, our data demonstrate an effective BPS ED activity at μM concentrations, suggesting that further studies are needed before considering its use in industrial application as an alternative to BPA.

Methoxychlor metabolite HPTE alters viability and differentiation of embryonic thymocytes from C57BL/6 mice

Endocrine-disrupting chemicals (EDC) are widespread in the built and natural environments. Heightened public awareness of their potential danger has led to concern about whether EDC and their metabolites have significant negative biological effects. Studies have shown that EDC like DDT and other organochlorine pesticides, such as methoxychlor (MXC), have adverse effects on immune cells, but no studies have addressed the impact of HPTE, the primary metabolite of MXC. To elucidate the presence and significance of HPTE adverse effects, this study explored the impact of HPTE on a critical window and component of immune system development, embryonic T-cell development. Lesions at this phase of development can lead to lifelong immune dysfunction and increased incidence of immune disease, such as autoimmunity. Embry-onic thymocytes (GD 16-18) from C57BL/6 mice were subjected to an in vitro differentiation culture that mimicked early steps in thymocyte development in the presence of 0.005, 0.05, 0.5, 5, or 50 μM HPTE, or a model endocrine disruptor, DES. The results indicated that compared to the vehicle control, HPTE- and DES-induced death of thymocytes. Annexin-V staining and Caspase 8, markers of programed cell death, revealed that the loss of cells was due at least in part to induction of apoptosis. Moreover, HPTE-induced cell death not only resulted in selective loss of double positive thymocytes, but also loss of developing CD4 intermediate cells (post-double positive partially differentiated thymocyte population). Phenotypic analysis of thymocyte maturation (T-cell receptor, TCR) and TCR ligation (CD5) surface markers revealed that surviving embryonic thymocytes expressed low levels of both. Taken together these data demonstrate that immature embryonic thymocytes are sensitive to HPTE exposure and that HPTE exposure targets thymocyte populations undergoing critical differentiation steps. These findings suggest HPTE may play a pivotal role in MXC exposure-induced immune dysfunction.

The impact of FSH receptor polymorphism on time-to-pregnancy: a cross-sectional single-centre study

Background

Single nucleotide polymorphism of the follicle-stimulating hormone (FSH) receptor (FSHR) is an important marker of ovarian function. However, its role in female fecundity remains debatable. The aim of the study to assess the relationship of FSHR polymorphism of Serine/Serine, Asparagine/Asparagine and Asparagine/Serine variants directly against the time-to-pregnancy (TTP) in women.

Methods

Data were collected from 291 consecutive selected post-partum Caucasians using this criterion: ethnicity, age between 21 and 34-year-old new mothers and, 0–3 days after delivery of newborns in the Klaipeda University Hospital, Lithuania. Questionnaires on factors associated with conception were given to patients, and blood samples were collected for genomic DNA extractions as well as for analysis of follicle-stimulating hormone receptor gene polymorphism. Odds ratios (OR) and 95% confidence intervals (CI) for time-to-pregnancy were estimated by multivariate logistic regression. Women with unplanned pregnancies and those who received assisted reproductive technologies were not included in the study.

Results

After adjustment for other possible factors, increased risk for time-to-pregnancy of 12 or more months was associated with: Serine/Serine polymorphism variant (OR = 1.38, 95% CI 1.56–2.71, p = 0.007), age of 30 or more years (OR = 1.95, 95% CI 1.25–2.71, p = 0.015), gynaecological diseases in the past (OR = 2.21, 95% CI 1.12–5.74, p = 0.027), prior contraception use (OR = 1.87, 95% CI 1.14–3.64, p = 0.016), and fertility problems in the past (OR = 1.57, 95% CI 1.16–4.76, p = 0.019).

Conclusion

The results suggest a possible relationship of FSH receptor gene Serine/Serine variant for the lower possibility of conception during the first 12 months of planned conception.

Engaging One Health for Non-Communicable Diseases in Africa: Perspective for Mycotoxins

The role of mycotoxins-e.g., aflatoxins, ochratoxins, trichothecenes, zearalenone, fumonisins, tremorgenic toxins, and ergot alkaloids-has been recognized in the etiology of a number of diseases. In many African countries, the public health impact of chronic (indoor) and/or repeated (dietary) mycotoxin exposure is largely ignored hitherto, with impact on human health, food security, and export of African agricultural food products. Notwithstanding, African scientific research reached milestones that, when linked to findings gained by the international scientific community, make the design and implementation of science-driven governance schemes feasible. Starting from Nigeria as leading African Country, this article (i) overviews available data on mycotoxins exposure in Africa; (ii) discusses new food safety issues, such as the environment-feed-food chain and toxic exposures of food producing animals in risk assessment and management; (iii) identifies milestones for mycotoxins risk management already reached in West Africa; and (iv) points out preliminary operationalization aspects for shielding communities from direct (on health) and indirect (on trade, economies, and livelihoods) effects of mycotoxins. An African science-driven engaging of scientific knowledge by development actors is expected therefore. In particular, One health/One prevention is suggested, as it proved to be a strategic and sustainable development framework.

Impaired ovarian response to exogenous gonadotropins in female rat offspring born to mothers perinatally exposed to Bisphenol A

The ovary is sensitive to disruption by the environmental estrogen Bisphenol A (BPA). Our aim was to investigate whether perinatal exposure to BPA (50μg/kgday), orally administered, affects ovarian response to exogenous gonadotrophins (PMSG or PMSG+hCG) in prepubertal female offspring. An altered response to gonadotrophins was observed in BPA-exposed rats. Increased proportion of antral follicles, altered levels of ovarian steroidogenic enzymes, gonadotropin receptors, AR and ERβ were observed in PMSG group. Besides that, in response to PMSG+hCG, a persistent high Fshr mRNA expression and a decreased number of follicles with high expression of PR before ovulation were observed. After ovulation, there was an increase in antral atretic follicles, reduced Lhcgr mRNA expression and high serum levels of E2. Therefore, an early exposure to a low dose of BPA during perinatal period induces ovarian changes leading to an altered response to exogenous gonadotropin treatment later in life.

Deleterious Effects From Occupational Exposure to Ethylene Thiourea in Pregnant Women

Human exposure to endocrine disrupting chemicals (EDCs) has become common as a result of widespread application of these chemicals to the food supply, environmental contamination, and occupational exposures (Caserta et al., 2011). However, relatively little is known about the effects of EDCs such as ethylene thiourea (ETU) in developing fetuses and the lasting implications of this disruption on human development from birth through adulthood. Of highest concern are chronic, low-dose exposures among industrial and agricultural workers. Current knowledge regarding the significance of endocrine thyroid signaling on normal human development raises serious concerns about the possible deleterious effects of EDCs in the developing fetus, children, and mature adults. Occupational health nurses are critical in identifying women and families at increased risk of ETU exposure and mitigating early exposures in pregnancy.

Self-management and psychological-sexological interventions in patients with endometriosis: strategies, outcomes, and integration into clinical care

Endometriosis has a multifactorial etiology. The onset and progression of the disease are believed to be related to different pathogenic mechanisms. Among them, the environment and lifestyle may play significant roles. Diet, dietary supplements, physical exercise, osteopathy, massage, acupuncture, transcutaneous electrical nerve stimulation, and Chinese herbal medicine may represent a complementary and feasible approach in the treatment of symptoms related to the disease. In this narrative review, we aimed to examine the most updated evidence on these alternative approaches implicated in the self-management of the disease. In addition, several studies have demonstrated that endometriosis may negatively impact mental health and quality of life, suggesting that affected women may have an increased risk of developing psychological suffering as well as sexual problems due to the presence of pain. In light of these findings, we discuss the importance of integrating psychological interventions (including psychotherapy) and sexual therapy in endometriosis treatment.

Potential exposure to endocrine disrupting chemicals and selected adverse pregnancy outcomes: a follow-up study of pregnant women referred for occupational counselling

BACKGROUND

Experimental evidence indicates that fetal exposure to xenobiotics with the potential to interfere with the endogenous steroid hormone regulation of fetal development may reduce birth weight. However, epidemiological studies are limited. The aim of the study was to investigate whether potential occupational exposure to endocrine disrupting chemicals (EDC) of the mother during pregnancy is associated with preterm birth and low birth weight.

METHODS

Pregnant women referred to an Occupational Health Clinic (OHC) in two Danish regions (Copenhagen or Aarhus) between 1984 and 2010, suspected of being exposed to occupational reproductive hazards were included in the study. A job exposure matrix enabled estimation of potential occupational exposure to EDC on the basis of job title. Births by women potentially exposed to EDC (n = 582) were compared to births by women referred to an OHC on the suspicion of other exposures than EDC (n = 620), and to a sample of births by all occupationally active women in the same geographical regions (n = 346,544), including 1,077 births of the referred women's non-referred pregnancies.

RESULTS

No indications of reduced birth weight or increased risk of preterm birth were found among women potentially exposed to EDC. Women potentially exposed to EDC had children with a higher birth weight compared to the sample of occupationally active women but not compared to other women referred to an OHC.

CONCLUSIONS

Potential maternal exposure to EDC at Danish workplaces is not related to low birth weight or preterm birth among women referred to occupational counselling. Occupational exposures might be too weak on the average to cause these adverse effects or counselling at the OHCs is effective in preventing them.

Environmental Contaminants and Reproductive Bodies: Provider Perspectives on Risk, Gender, and Responsibility

Increasingly, leading health organizations recommend that women who are pregnant or considering pregnancy avoid certain toxic chemicals found in our products, homes, and communities in order to protect fetuses from developmental and future harm. In the contemporary United States, women's maternal bodies have been treated as sites of exceptional risk and individual responsibility. Many studies have examined this phenomenon through the lens of lifestyle behaviors like smoking, drinking, and exercise. However, we know little about how environmental hazards fit into the dominant framework of gendered, individual responsibility for risk regulation. I draw on in-depth interviews with 19 reproductive healthcare providers in the United States to explore how they think about their patients' exposure to environmental contaminants and sometimes subvert this gendered, individualized responsibility and adopt more collective frames for understanding risk.

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.

Perinatal exposure to mixtures of endocrine disrupting chemicals reduces female rat follicle reserves and accelerates reproductive aging

Exposure to endocrine disrupting chemicals (EDCs) during development can have negative consequences later in life. In this study we investigated the effect of perinatal exposure to mixtures of human relevant EDCs on the female reproductive system. Rat dams were exposed to a mixture of phthalates, pesticides, UV-filters, bisphenol A, butylparaben, as well as paracetamol. The compounds were tested together (Totalmix) or in subgroups with anti-androgenic (AAmix) or estrogenic (Emix) potentials. Paracetamol was tested separately. In pre-pubertal rats, a significant reduction in primordial follicle numbers was seen in AAmix and PM groups, and reduced plasma levels of prolactin was seen in AAmix. In one-year-old animals, the incidence of irregular estrous cycles was higher after Totalmix-exposure and reduced ovary weights were seen in Totalmix, AAmix, and PM groups. These findings resemble premature ovarian insufficiency in humans, and raises concern regarding potential effects of mixtures of EDCs on female reproductive function.

Mechanisms of the Maternal Exposome and Implications for Health Outcomes

It is well established that the environment contributes to health. However, few studies have evaluated environmental exposures in women that may influence future health of their offspring. Knowledge gained may inform nursing how to better advocate for patients and families, and provide individualized interventions and education. Therefore, a more comprehensive investigation of the maternal exposome to uncover mechanistic insight into complex disease in offspring is warranted. To advance understanding of biologic mechanisms that contribute to high-risk birth outcomes and offspring predisposition to disease, it will be necessary to measure a range of exposures and biomarkers before and during pregnancy.

Associations between maternal phenolic exposure and cord sex hormones in male newborns

STUDY QUESTION

Are maternal urinary phenol concentrations associated with cord steroid hormone levels and anogenital distance (AGD) in male newborns?

SUMMARY ANSWER

High maternal urinary Bisphenol A (BPA) levels are associated with decreases in cord testosterone levels and the ratio of testosterone to estradiol in male newborns, but there was no significant association with AGD.

WHAT IS KNOWN ALREADY

Early life exposure to phenolic endocrine disrupting compounds (EDCs) is known to disrupt hormonal activities and affect reproductive development in males. However, studies on the health effects of prenatal human exposure are scarce.

STUDY DESIGN, SIZE, DURATION

This was a cross-sectional study to investigate the association between maternal phenolic exposure and cord sex steroid hormones and AGD in male newborns. We recruited 100 mother-infant pairs from each of two hospitals, one in a polluted town (Guiyu) and the other in a cleaner town (Haojiang), from September 2010 to September 2011.

PARTICIPANTS/MATERIALS, SETTING, METHODS

One hundred and seventy eight maternal urine samples and 137 cord blood samples were available for quantification, thus 137 complete records entered into the final analysis. Of them, 77 pairs were from Guiyu, and 60 were from Haojiang. The chemical concentrations were determined by solid phase extraction and gas chromatography-mass spectrometry (SPE-GC-MS), and cord sex hormones were detected by radioimmunoassay (RIA). Neonatal anthropometric parameters including AGD were measured.

MAIN RESULTS AND THE ROLE OF CHANCE

Log2-transformed maternal urinary BPA concentration was negatively correlated with testosterone level and the ratio of testosterone to estradiol (T/E2) in male fetal cord blood after adjustment for potential confounders in linear regression models (βadjusted = -31.09 (95% CI, -53.07 to -9.11) and βadjusted = -0.08 (95% CI, -0.13 to -0.01), respectively). Moreover, compared with the lowest quartile group of BPA level, the highest group showed a significant decrease in testosterone level and T/E2 (βadjusted = -179.84 (95% CI, -333.45 to -26.24) and βadjusted = -0.37 (95% CI, -0.81 to 0.07), respectively). No significant associations between AGD or anogenital index (AGI, [AGI = AGD/birthweight (mm/kg)]) and phenolic EDCs or cord hormone levels were found.

LIMITATIONS, REASONS FOR CAUTION

Results in the present study should be interpreted with caution because of its cross-sectional nature, small sample size and sampling time.

WIDER IMPLICATIONS OF THE FINDINGS

Testosterone plays an important role in sex differentiation and normal development of the fetus and newborn, and the balance between testosterone and estradiol is thought an important mediator of prostate disease. Therefore, our findings may have important implications for human reproductive health.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the National Natural Science Foundation of China (21377077) and Guangdong University Project for International Cooperation and Innovation Platform (2013gjhz0007). The authors declare they have no actual or potential competing financial interests.