Prenatal Exposure to PFAS, Associations with Preterm Birth and Modification by Maternal Estrogen Levels: The Maoming Birth Study

Developmental exposure to perfluorooctane sulfonate(PFOS) impairs the endometrial receptivity

Perfluorooctane sulfonate (PFOS) is a widely used chemical in industrial production. It can be introduced into the environment through multiple pathways and exhibits resistance to degradation. Recent research has demonstrated a significant correlation between its exposure levels in the human body and the incidence of various diseases. The expression of genes related to endometrial receptivity and the differentiation of human endometrial stromal cells (hESCs) were assessed in this study concerning PFOS. In this study, we investigated the effect of PFOS exposure on endometrial tolerance by cell and animal experiments. The activity against endometrial mesenchymal cells was significantly reduced by PFOS intervention, and the apoptosis flow assay results showed that PFOS significantly promoted cell death in a concentration-dependent manner. Transmission electron microscopy results revealed mitochondrial damage in the PFOS-intervened group, and WB results showed that the expression levels of endometrial tolerance-related proteins Homeobox A10 (HOXA10) and integrin beta3 (ITGB3) were decreased, and the expression level of Forkhead box O1 (FOXO1) protein was increased. Animal studies have shown that PFOS exposure can change uterine morphology, cause obvious damage to pinopodes morphology, change the estrous cycle of mice, and affect endometrial receptivity In the present study, we found that PFOS may synergistically affect the viability of endometrial mesenchymal stromal cells through accumulation in vivo, and that PFOS may contribute to the failure of embryo implantation by affecting mitochondrial function and consequently endometrial permissive sites.

Legacy and alternative per- and polyfluoroalkyl substances spatiotemporal distribution in China: Human exposure, environmental media, and risk assessment

In recent decades, China's rapid development has led to significant environmental pollution from the widespread use of chemical products. Per- and polyfluoroalkyl substances (PFAS) are among the most concerning pollutants due to their persistence and bioaccumulation. This article assesses PFAS exposure levels, distribution, and health risks in Chinese blood, environment, and food. Out of 4037 papers retrieved from November 2022 to December 31, 2023, 351 articles met the criteria. Findings show perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) as the main PFAS in both Chinese populations and the environment. The highest PFOA levels in Chinese populations were in Shandong (53.868 ng/mL), while Hubei had the highest PFOS levels (43.874 ng/mL). Similarly, water samples from Sichuan (2115.204 ng/L) and Jiangsu (368.134 ng/L) had the highest PFOA and PFOS levels, respectively. Although localized areas showed high PFAS concentrations. Additionally, developed areas had higher PFAS contamination. The researches conducted in areas such as Qinghai and Hainan remain limited, underscoring the imperative for further investigation. Temporal analysis indicates declining levels of some PFAS, but emerging alternatives require more research. Limited studies on PFAS concentrations in soil, atmosphere, and food emphasize the need for comprehensive research to mitigate human exposure.

Transplacental transfer of perfluorinated and poly-fluorinated substances in maternal-cord serum and association with birth weight: A birth cohort study, China

Although the effects of traditional perfluorinated and polyfluorinated substances (PFASs) exposure have been extensively explored, research on novel PFASs remains limited, and there is a lack of data regarding their placental transfer and fetal impact. Herein, we aimed to examine maternal and fetal PFASs exposure levels, placental transfer efficiency (TTE), and the consequences of prenatal exposure on birth weight. The study included 214 mother-child pairs recruited in Wuxi birth cohort from 2019 to 2021. Twenty-three PFASs were quantified in maternal serum during the second trimester and umbilical serum during delivery. Median concentrations of ∑23PFASs in maternal and cord sera were 9.34 and 6.88 ng/mL, respectively. The novel alternatives exhibited elevated levels of maternal and fetal exposure, such as perfluorovaleric acid (PFPeA, 2.00 ng/mL and 1.66 ng/mL, respectively) and perfluorohexane sulfonate (PFHxS, 1.77 and 1.14 ng/mL, respectively). With increasing carbon chain length, the TTE of perfluorocarbonic acid (PFCAs) displayed a pattern of initially decreasing before subsequently increasing, with novel alternatives exhibiting a relatively high TTE. Multiple linear regression showed that exposure to perfluorobutane sulfonate (PFBS) and PFPeA in cord serum positively correlated with the birth weight of female infants (β = 231.04 g, 95% confidence interval [CI]: 21.73-440.36; β = 121.26 g, 95% CI: 29.51-213.00). No nonlinear relationship was observed between cord serum PFASs and birth weight. The weighted quantile sum (WQS) regression analysis has reaffirmed that PFPeA and PFBS were predominant contributors to the positive correlation observed between the mixture of PFASs and birth weight. Our findings suggest that novel PFASs may exhibit a heightened susceptibility for transplacental transfer and that exposure to PFBS and PFPeA during pregnancy could be linked to increased birth weight.

Raman-guided exploration of placental microplastic exposure: Unraveling the polymeric tapestry and assessing developmental implications

The prevalence of microplastics in human tissues and their potential reproductive toxicity have been increasingly documented, yet their appearance in the placenta and the impact of microplastic exposure on human fertility and pregnancy remains uncertain. Utilizing an inVia™ confocal Raman microspectroscopy by Renishaw equipped with a detection threshold as low as 0.25 µm, our study examined the microplastics in the placentas of 50 women post-delivery and investigated their correlations with gestational age, and neonatal length and weight. We found that 40 microplastic particles were identified across 31 of 50 placentas, averaging 2.35 ± 1.25 µm in size and ranging from 1.03 to 6.84 µm. Seven distinct polymer types were detected, with PTFE, PS, and ABS being the most prevalent. Notably, no significant difference across the normal, PTFE, and PS groups for all demographic variables examined was identified, nor as pathological alterations of placental tissues. In conclusion, our findings demonstrate the presence of seven microplastic polymers in human placentas, with PTFE, PS, and ABS being the most prevalent. However, maternal and neonatal parameters were not affected, and further studies are necessary to elucidate the effects of microplastics on developmental outcomes and fetal health.

Isomer of per- and polyfluoroalkyl substances and red blood cell indices in adults: The Isomers of C8 Health Project in China

This study aimed to explore the isomer-specific, sex-specific, and joint associations of PFAS and red blood cell indices. We used data of 1,238 adults from the Isomers of C8 Health Project in China. Associations of PFAS isomers and red blood cell indices were explored using multiple linear regression models, Bayesian Kernel Machine Regression models and subgroup analysis across sex. We found that serum concentration of linear (n-) and branched (Br-) isomers of perfluorooctane sulfonate (PFOS) and perfluorohexanesulfonic acid (PFHxS) were significantly associated with red blood cell indices in single-pollutant models, with stronger associations observed for n-PFHxS than Br-PFHxS, in women than in men. For instance, the estimated percentage change in hemoglobin concentration for n-PFHxS (3.65%; 95% CI: 2.95%, 4.34%) was larger than that for Br-PFHxS (0.96%; 95% CI: 0.52%, 1.40%). The estimated percentage change in red blood cell count for n-PFHxS in women (2.55%; 95% CI: 1.81%, 3.28%) was significantly higher than that in men (0.12%; 95% CI: -1.04%, 1.29%) (Pinter < 0.001). Similarly, sex-specific positive association of PFAS mixture and outcomes was observed. Therefore, the structure, susceptive population, and joint effect of PFAS isomers should be taken into consideration when evaluating the health risk of chemicals.

Exposure to Synthetic Endocrine-Disrupting Chemicals in Relation to Maternal and Fetal Sex Steroid Hormones: A Scoping Review

PURPOSE OF REVIEW

Many synthetic endocrine-disrupting chemicals (EDCs) are ubiquitous in the environment and highly detected among pregnant people. These chemicals may disrupt maternal and/or fetal sex steroid hormones, which are critical to pregnancy maintenance and fetal development. Here, we review the epidemiological literature examining prenatal exposure to common synthetic EDCs in relation to maternal and fetal sex steroid hormones.

RECENT FINDINGS

We performed a literature search using PubMed, SCOPUS, and Embase, ultimately identifying 29 articles for full review. Phenols, parabens, and persistent organic pollutants generally showed inverse associations with androgens, estrogens, and progesterone. Phthalates and per-and polyfluoroalkyl substances tended to be inversely associated with progesterone, while evidence regarding androgens and estrogens was mixed. Inconsistent, but noteworthy, differences by fetal sex and timing of exposure/outcome were observed. Overall, the literature suggests EDCs may disrupt maternal and fetal sex steroid activity, though findings are mixed. Given the pervasive, high-volume production of these synthetic chemicals and the critical functions sex steroid hormones play during gestation, additional research is warranted.

Effect of per- and polyfluoroalkyl substances on neurodevelopment: Evidence-based risk assessment in the TRAEC strategy context

Although emerging evidence on the association between per- and polyfluoroalkyl substances (PFASs) and neurodevelopment have been investigated, there is no consensus on the effect of maternal PFASs on neurodevelopment in offspring. Here, we assessed the risk of maternal PFASs exposure on the neurodevelopment of offspring using a novel Targeted Risk Assessment of Environmental Chemicals (TRAEC) strategy based on multiple evidence. The evidence from five online databases were analyzed the effect of PFASs on neurodevelopment. The potential neurodevelopment risk of PFASs was evaluated by the TRAEC strategy, which was conducted on a comprehensive scoring system with reliability, correlation, outcome fitness and integrity. The studies from five databases and additional researchers' experiments were included the present study to proceed following risk assessment. Based on the framework with TRAEC strategy, the comprehensive evaluation of health risks was classified as low (absolute value 0-4), medium (absolute value 4-8), high (absolute value 8-10). In the present study, the effect of PFASs exposure on neurodevelopment was a medium-risk level with 5.61 overall risk-score. The population-attributable risk (PAR) was 8.26 % for maternal PFASs exposure. The study identified a low-risk effect of prenatal PFASs exposure on ASD and behavioral disabilities. The chain length, type of PFASs and neurodevelopmental trajectories contributed to the risk of maternal PFASs on the neurodevelopment of offspring. Consistent with results of four criteria-based tools (ToxRTool, SciRAP, OHAT and IRIS), health risk assessment based on the TRAEC strategy demonstrated robustness and reliability in the present study. These results illustrated a medium-risk effect of maternal PFASs exposure on neurodevelopmental disorders of offspring. In addition, the TRAEC strategy provided a scientific and structured method for effect evaluation between prenatal PFASs and neurodevelopmental disorders, promoting the consistency and validation in risk assessment.

Associations of prenatal exposure to per- and polyfluoroalkyl substances and fetal sex hormones in the Guangxi Zhuang Birth Cohort Study: Greater effect of long-chain PFAS

Fetal sex hormone homeostasis disruption could lead to reproductive and developmental abnormalities. However, previous studies have reported inconsistent findings regarding the association of maternal per- and polyfluoroalkyl substances (PFAS) exposure with fetal sex hormone levels. A total of 277 mother-infant pairs from the Guangxi Zhuang Birth Cohort Study between 2015 and 2019 were selected. We quantified nine PFAS in maternal serum in early pregnancy, and detected three sex hormones, namely, estradiol (E2), progesterone (P4) and testosterone (TT), in cord blood. The generalized linear model (GLM) and Bayesian kernel machine regression (BKMR) model were used for single- and multiple-exposure analyses, respectively. In the GLM, there was no significant association between an individual PFAS and any hormone level or the E2/TT ratio, but a negative association between perfluorododecanoic acid (PFDoA) exposure and P4 levels in female infants was observed after stratification by sex. In the BKMR, a mixture of nine PFAS was positively associated with E2 levels and the E2/TT ratio, with the same main contributors, i.e., perfluoroundecanoic acid (PFUnA). And PFAS mixtures were not associated with P4 or TT levels. After stratification by infant sex, positive associations of PFAS mixtures with E2 levels and the E2/TT ratio were observed only in male infants, with the same main contributors, i.e., PFUnA. There was a positive association between PFAS mixtures and P4 levels in male infants, in which PFUnA was the main contributor; but a reverse association between PFAS mixtures and P4 levels in female infants, in which PFDoA was the main contributor. This study suggested that prenatal exposure to PFAS mixtures is associated with fetal sex hormones, and long-chain PFAS may play an important role in this association. Furthermore, sex differences in the association of maternal PFAS exposure with E2 and P4 levels need additional attention.

Perfluorooctane sulfonate (PFOS) induces apoptosis and autophagy by inhibition of PI3K/AKT/mTOR pathway in human granulosa cell line KGN

Perfluorooctane sulfonate (PFOS) is recognized as an environmental endocrine disruptor with widespread use in industrial manufacturing and daily life, contributing to various public health concerns. However, the precise impacts of PFOS on the ovary and its regulatory mechanisms remain unclear. This study aims to delineate the ovarian toxicity of PFOS and scrutinize its effects on apoptosis and autophagy through modulation of the PI3K/AKT/mTOR pathway in the human granulosa cell line (KGN). Cell viability, assessed via the Cell Counting Kit-8 (CCK8), revealed a dose-dependent reduction in cell viability upon PFOS exposure. Flow cytometry analysis demonstrated an elevated proportion of apoptotic cells following PFOS treatment. Western blot analyses unveiled increased expression of Bax, Cyt c, cleaved caspase-9, and LC3-II/I, coupled with decreased expression of Bcl-2 and p62. Transmission electron microscopy (TEM) observations illustrated a heightened number of autophagosomes induced by PFOS. Molecular docking investigations, in conjunction with Western blot experiments, substantiated PFOS's significant inhibition of the PI3K/AKT/mTOR signaling pathway. These findings collectively underscore that PFOS induces apoptosis and autophagy in KGN cells through modulation of the PI3K/AKT/mTOR pathway, providing experimental evidence for PFOS-induced ovarian toxicity and elucidating the underlying regulatory mechanisms in KGN cells.