Per- and Polyfluoroalkyl Substances Differentially Inhibit Placental Trophoblast Migration and Invasion In Vitro

Prenatal per- and polyfluoroalkyl substances and blood pressure trajectories in the New Hampshire Birth Cohort Study

Per- and polyfluoroalkyl substances (PFAS) have been associated with increased risk of hypertensive disorders of pregnancy, but whether PFAS influence blood pressure (BP) trajectories among normotensive pregnant women is unknown. We examined associations between PFAS mixtures and BP trajectories during pregnancy among normotensive women. PFAS concentrations, including perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), and perfluorodecanoate (PFDA), were measured in plasma collected at ∼28 gestational weeks among pregnant women enrolled in the New Hampshire Birth Cohort Study (2009-2018). Systolic BP (SBP) and diastolic BP (DBP) were abstracted from pregnancy medical records. We identified BP trajectories using latent class trajectory modeling and evaluated associations between PFAS mixtures and BP trajectories using probit Bayesian kernel machine regression and multinomial quantile g-computation. We used linear mixed models to examine individual PFAS and BP changes during the third trimester. Models were adjusted for sociodemographic, lifestyle, and reproductive factors, and gestational week of blood sample collection. During late pregnancy, plasma PFOS was associated with greater increases in SBP and PFHxS was associated with greater increases in DBP. Over the third trimester, each doubling in plasma PFOS was associated with 0.07 mmHg (95% CI: -0.01, 0.14) increase per week in SBP, and each doubling in plasma PFHxS was associated with 0.07 mmHg (95% CI: 0.02, 0.12) increase per week in DBP. Our study provides additional evidence suggesting that PFAS may adversely influence blood pressure even among normotensive women.

Sex-specific effects of in utero exposure to per- and polyfluoroalkyl substances on placental development

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants that may impact placental function, and potentially gestational age acceleration (GAA), a deviation from reported and predicted gestational age. GAA potentially represents differences in cell maturation in response to a challenging environment.

OBJECTIVE

This study aimed to characterize the effects of individual and mixtures of PFAS on GAA, cell composition, birth length, and birthweight.

METHODS

Pregnant peoples were recruited from around Little Rock, Arkansas, United States between 2011 and 2014. We utilized placental DNA methylation profiles of 153 healthy pregnancies to calculate GAA and estimate the proportions of six placental cell types. PFAS were quantified in homogenized placental tissue using high-performance liquid chromatography-tandem mass spectrometry. Five PFAS were detected in over 70% of samples. We studied these five PFAS individually using multiple linear regression and as a mixture using quantile g-computation, while adjusting for confounders. The dependent variables in our models included GAA, cell proportions, birthweight, and birth length.

RESULTS

We did not observe associations between PFAS and any of our outcomes in our primary models. While GAA in male placentas were not significantly affected by PFAS, the PFAS mixture associated with decreased syncytiotrophoblast proportion (Ψ = -0.018, 95% CI [-0.032, -0.004]). PFAS mixture did not alter cell proportions in female placentas but was associated with increased GAA (Ψ = 0.269, 95% CI [0.026, 0.513]). Similarly, for females, greater GAA was associated with PFOA (β = 0.141, 95% CI [-0.016,0.040]) and PFOS (β = 0.205, 95% CI [-0.020,0.0416]).

DISCUSSION

We illustrate that PFAS may influence placental development in a sex specific manner. Suggested by decrease in syncytotrophoblast, male placenta may experience a more stunted development due to PFAS exposure. Alternatively, female placentas exhibited increased GAA, a plausible marker of elevated developmental maturation in the face of environmental adversity.

Exposure to environmentally relevant levels of GenX affects placental and offspring development in mice

Hexafluoropropylene Oxide Dimer Acid (GenX or HFPO-DA), a fluorochemical used in industrial applications such as non-stick coatings and water-repellent textiles, has emerged as a replacement for perfluorooctanoic acid (PFOA). Its widespread use has led to detection in air, soil, and drinking water, raising concerns about potential health impacts. This study investigates the effects of exposure to environmentally relevant levels of GenX on placental and offspring development in mice. Female mice were exposed to GenX for short-term (11 days) or subchronic (100 days) durations. Both short-term and subchronic exposure resulted in alterations in body weight gain, placental weight, and placental efficiency. Dams exposed subchronically also exhibit altered fetal weight and impaired placental structure. In the labyrinth layer of placenta, subchronic exposure to GenX caused disordered vasculature, characterized by enlarged vessel lumens, discontinuous signals of maternal (MCT1) and fetal (MCT4) vascular networks, and impaired mitochondria in fetal sinus endothelial cells. The placental mRNA profile revealed imbalanced expression of factors essential for proper angiogenesis, with increased levels of Vegfa and Angpt1, and decreased levels of Tie2. Additionally, male pups of the subchronically exposed dams exhibited higher birth weight, increased weight gain and reduced anogenital distance (AGD), while premature puberty onset was observed in female pups. This study provides the first evidence that subchronic exposure to environmentally relevant levels of GenX affects placental angiogenesis, potentially contributing to altered development in offspring. These findings offer new insights into the health impacts of GenX on reproductive development and raise concerns about its safety as a PFOA alternative.

Per- and polyfluoroalkyl substances (PFAS) and hypertensive disorders of Pregnancy- integration of epidemiological and mechanistic evidence

BACKGROUND

Hypertensive disorders of pregnancy (HDP) remain a significant global health burden despite medical advancements. HDP prevalence appears to be rising, leading to increased maternal and fetal complications, mortality, and substantial healthcare costs. The etiology of HDP are complex and multifaceted, influenced by factors like nutrition, obesity, stress, metabolic disorders, and genetics. Emerging evidence suggests environmental pollutants, particularly Per- and polyfluoroalkyl substances (PFAS), may contribute to HDP development.

OBJECTIVE

This review integrates epidemiological and mechanistic data to explore the intricate relationship between PFAS exposure and HDP.

EPIDEMIOLOGICAL EVIDENCE

Studies show varying degrees of association between PFAS exposure and HDP, with some demonstrating positive correlations, particularly with preeclampsia. Meta-analyses suggest potential fetal sex-specific differences in these associations.

MECHANISTIC INSIGHTS

Mechanistically, PFAS exposure appears to disrupt vascular hemodynamics, placental development, and critical processes like angiogenesis and sex steroid regulation. Experimental studies reveal alterations in the renin-angiotensin system, trophoblast invasion, oxidative stress, inflammation, and hormonal dysregulation - all of which contribute to HDP pathogenesis. Elucidating these mechanisms is crucial for developing preventive strategies.

THERAPEUTIC POTENTIAL

Targeted interventions such as AT2R agonists, caspase inhibitors, and modulation of specific microRNAs show promise in mitigating adverse outcomes associated with PFAS exposure during pregnancy.

KNOWLEDGE GAPS AND FUTURE DIRECTIONS

Further research is needed to comprehensively understand the full spectrum of PFAS-induced placental alterations and their long-term implications for maternal and fetal health. This knowledge will be instrumental in developing effective preventive and therapeutic strategies for HDP in a changing environmental landscape.

Potential causal associations between perfluoroalkyl substances exposure and adverse pregnancy outcomes: A bidirectional two-sample mendelian randomization study

Maternal exposure to per- and polyfluoroalkyl substances (PFASs) has been linked to adverse pregnancy outcomes (APOs). Nonetheless, the genetic causality underlying this association remains unknown. This research employed a bidirectional two-sample Mendelian randomization (MR) to investigate the potential causal associations between PFASs exposure and APOs risk. PFASs data were sourced from the GWAS Catalog, and APOs data were retrieved from the FinnGen consortium. Causal estimation primarily employed inverse variance weighting, with Cochran's Q test for instrumental variable heterogeneity, and MR-Egger, MR-PRESSO, and leave-one-out tests for sensitivity analyses. The possibility of reverse causality was investigated through reverse MR. MR evidence revealed a notable correlation between perfluorooctanoic acid (PFOA) and abruptio placentae (OR=1.498, P=0.026), as well as short gestation and low birth weight (OR=1.720, P=0.013). Exposure to perfluorooctanesulfonic acid (PFOS) increased the risk of preeclampsia or eclampsia (OR=1.128, P=0.030) and gestational hypertension (OR=1.076, P=0.049), but decreased the risk of premature rupture of membranes (OR=0.916, P=0.033). The results obtained were consistent across various sensitivity analyses. Reverse MR results was negative. These findings may provide a reference for prevention strategies and intervention measures for PFASs exposure and APOs, and provide a framework for studying the causal effects of environmental pollutant exposure and human diseases.

Association between exposure to per- and polyfluoroalkyl substances and missed miscarriage: A hospital-based case-control study in Shanghai, China

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental pollutants linked to reproductive disruptions. This study investigated the relationship between PFAS exposure and missed miscarriage in a hospital-based, case-control study in Shanghai, China. There were 393 women in our research, including 198 cases and 195 controls. Concentrations of 30 PFAS in plasma were quantified using HPLC-MS/MS, and 15 PFAS were detected at a rate greater than 90 percent. PFOA, L-PFOS, and PFOS isomers were significantly higher in the cases than those in the controls. 13 PFAS showed significant positive associations with miscarriage risk after adjustment for confounders, particularly PFOA (OR: 2.99, 95 % CI: 1.96-4.68) and various PFOS isomers. BKMR analysis confirmed higher overall PFAS levels were associated with increased miscarriage risk. These findings highlight the potential reproductive toxicity of PFAS and underscore the need for further investigations and regulatory actions to mitigate PFAS exposure in pregnant women.

Exploring the sources, occurrence, transformation, toxicity, monitoring, and remediation strategies of per- and polyfluoroalkyl substances: a review

Per- and polyfluoroalkyl substances (PFAS), a class of man-made chemicals, possess unique properties that have rendered them indispensable in various industries and consumer goods. However, their extensive use and persistence in the environment have raised concerns about their potential repercussions on human health and the ecosystem. This review provides insights into the sources, occurrence, transformation, impacts, fate, monitoring, and remediation strategies for PFAS. Once released into the environment, these chemicals undergo intricate transformation processes, such as degradation, bioaccumulation, and biomagnification, which result in their far-reaching distribution and persistence. Their chemical stability results in persistent pollution, with far-reaching ecological and human health implications. Remediation strategies for PFAS are still in their infancy, and researchers are exploring innovative and sustainable methods for treating contaminated environments. Promising technologies such as adsorption, biodegradation, and electrochemical oxidation have shown the potential to remove PFAS from contaminated sites, yet the search for more efficient and sustainable solutions continues. In conclusion, this review emphasizes the urgent need for continued research and innovation to address the global environmental challenge posed by PFAS. As we move forward, it is imperative to prioritize sustainable solutions that minimize the detrimental consequences of these substances on human health and the environment.

Hazard identification of endocrine-disrupting carcinogens (EDCs) in relation to cancers in humans

Endocrine disrupting chemicals or carcinogens have been known for decades for their endocrine signal disruption. Endocrine disrupting chemicals are a serious concern and they have been included in the top priority toxicants and persistent organic pollutants. Therefore, researchers have been working for a long time to understand their mechanisms of interaction in different human organs. Several reports are available about the carcinogen potential of these chemicals. The presented review is an endeavor to understand the hazard identification associated with endocrine disrupting carcinogens in relation to the human body. The paper discusses the major endocrine disrupting carcinogens and their potency for carcinogenesis. It discusses human exposure, route of entry, carcinogenicity and mechanisms. In addition, the paper discusses the research gaps and bottlenecks associated with the research. Moreover, it discusses the limitations associated with the analytical techniques for detection of endocrine disrupting carcinogens.

Glyphosate modifies the gene expression and migration of trophoblastic cells without altering the process of angiogenesis or the implantation of blastocysts in vitro

Adverse pregnancy outcomes have been associated with the presence of glyphosate (G) in umbilical cord, serum, and urine samples from pregnant women. Our aim was to study the effect of G on blastocyst implantation using an in vitro mouse model, and the migration and acquisition of endothelial phenotype of the human trophoblastic HTR8/SVneo (H8) cells. In mouse blastocysts, no differences in attachment time and implantation outgrowth area were observed after G exposure. H8 cell migration was stimulated by 0.625 μM G without cytotoxicity. After 6 h, the mRNA expression of vascular endothelial growth factor (VEGF) and C-C motif chemokine ligand 2 (CCL2) was upregulated in H8 cells exposed to 1.25 μM G when compared vehicle-treated cells (p ≤ 0.05). No differences were observed in interleukin 11, VEGF receptor 1, and coagulation factor II thrombin receptor in H8 cells exposed to different concentrations of G for 6 h compared to the vehicle. Interestingly, exposure to G did not alter angiogenesis as measured by a tube formation assay. Taken all together, these results suggest that G exposure may contribute as a risk factor during pregnancy, due to its ability to alter trophoblast migration and gene expression.

External liquid calibration method for iodide chemical ionization mass spectrometry enables quantification of gas-phase per- and polyfluoroalkyl substances (PFAS) dynamics in indoor air

Per- and polyfluoroalkyl substances (PFAS) are manufactured chemicals that have been detected across the globe. Fluorotelomer alcohols (FTOHs) are one PFAS class commonly found in indoor air due to emissions from consumer products (e.g., textiles and food packaging) and are human metabolic, atmospheric oxidative, and industrial precursors of perfluoroalkyl carboxylic acids (PFCAs). We developed a quantitative method for real-time analysis of gas-phase FTOHs, perfluoroalkyl acids (PFCAs and GenX), one perfluorooctane sulfonamide (EtFOSA), one fluorotelomer diol (FTdiOH), and one fluorinated ether (E2) using high-resolution time-of-flight chemical ionization mass spectrometry equipped with iodide reagent ion chemistry (I-HR-ToF-CIMS). Herein, we present a direct liquid injection method for external calibration, providing detection limits of 0.19-3.1 pptv for 3 s averaging and 0.02-0.44 pptv for 120 s averaging, with the exception of E2, which had detection limits of 1700 and 220 pptv for 3- and 120 s averaging, respectively. These calibrations enabled real-time gas-phase quantification of 6 : 2 FTOH in room air while microwaving popcorn, with an average peak air concentration of 31.6 ± 4.5 pptv measured 2 meters from a closed microwave. Additionally, 8 : 2 and 10 : 2 FTOH concentrations in indoor air were measured in the presence and absence of a rain jacket, with observed peak concentrations of 110 and 25 pptv, respectively. Our work demonstrates the ability of I-HR-ToF-CIMS to provide real-time air measurements of PFAS relevant to indoor human exposure settings and allow for PFAS source identification. We expect that real-time quantification of other gas-phase PFAS classes is possible, enabling advances in understanding PFAS sources, chemistry, and partitioning.

Public Health Risks of PFAS-Related Immunotoxicity Are Real

PURPOSE OF REVIEW

The discovery of per- and polyfluoroalkyl substances (PFAS) in the environment and humans worldwide has ignited scientific research, government inquiry, and public concern over numerous adverse health effects associated with PFAS exposure. In this review, we discuss the use of PFAS immunotoxicity data in regulatory and clinical decision-making contexts and question whether recent efforts adequately account for PFAS immunotoxicity in public health decision-making.

RECENT FINDINGS

Government and academic reviews confirm the strongest human evidence for PFAS immunotoxicity is reduced antibody production in response to vaccinations, particularly for tetanus and diphtheria. However, recent events, such as the economic analysis supporting the proposed national primary drinking water regulations and clinical monitoring recommendations, indicate a failure to adequately incorporate these data into regulatory and clinical decisions. To be more protective of public health, we recommend using all relevant immunotoxicity data to inform current and future PFAS-related chemical risk assessment and regulation. Biological measures of immune system effects, such as reduced antibody levels in response to vaccination, should be used as valid and informative markers of health outcomes and risks associated with PFAS exposure. Routine toxicity testing should be expanded to include immunotoxicity evaluations in adult and developing organisms. In addition, clinical recommendations for PFAS-exposed individuals and communities should be revisited and strengthened to provide guidance on incorporating immune system monitoring and other actions that can be taken to protect against adverse health outcomes.

Reproductive toxicity of PFOA, PFOS and their substitutes: A review based on epidemiological and toxicological evidence

Per- and polyfluoroalkyl substances (PFAS) have already drawn a lot of attention for their accumulation and reproductive toxicity in organisms. Perfluorooctanoic acid (PFOA) and perfluorooctanoic sulfonate (PFOS), two representative PFAS, are toxic to humans and animals. Due to their widespread use in environmental media with multiple toxicities, PFOA and PFOS have been banned in numerous countries, and many substitutes have been produced to meet market requirements. Unfortunately, most alternatives to PFOA and PFOS have proven to be cumulative and highly toxic. Of the reported multiple organ toxicities, reproductive toxicity deserves special attention. It has been confirmed through epidemiological studies that PFOS and PFOA are not only associated with reduced testosterone levels in humans, but also with an association with damage to the integrity of the blood testicular barrier. In addition, for women, PFOA and PFOS are correlated with abnormal sex hormone levels, and increase the risk of infertility and abnormal menstrual cycle. Nevertheless, there is controversial evidence on the epidemiological relationship that exists between PFOA and PFOS as well as sperm quality and reproductive hormones, while the evidence from animal studies is relatively consistent. Based on the published papers, the potential toxicity mechanisms for PFOA, PFOS and their substitutes were reviewed. For males, PFOA and PFOS may produce reproductive toxicity in the following five ways: (1) Apoptosis and autophagy in spermatogenic cells; (2) Apoptosis and differentiation disorders of Leydig cells; (3) Oxidative stress in sperm and disturbance of Ca2+ channels in sperm membrane; (4) Degradation of delicate intercellular junctions between Sertoli cells; (5) Activation of brain nuclei and shift of hypothalamic metabolome. For females, PFOA and PFOS may produce reproductive toxicity in the following five ways: (1) Damage to oocytes through oxidative stress; (2) Inhibition of corpus luteum function; (3) Inhibition of steroid hormone synthesis; (4) Damage to follicles by affecting gap junction intercellular communication (GJIC); (5) Inhibition of placental function. Besides, PFAS substitutes show similar reproductive toxicity with PFOA and PFOS, and are even more toxic to the placenta. Finally, based on the existing knowledge, future developments and direction of efforts in this field are suggested.

Associations of per- and polyfluoroalkyl substances with maternal metabolic and inflammatory biomarkers in early-to-mid-pregnancy

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) can disrupt metabolism. Early-to-mid pregnancy is characterized by amplified metabolic processes and inflammation to support maternal adaptations and fetal growth. Thus, we cross-sectionally evaluated whether PFAS are individually and jointly associated with these processes in early-to-mid pregnancy.

METHODS

Pregnant Illinois women (n = 452) provided fasted blood samples at median 17 weeks gestation. We quantified serum perfluorononanoic (PFNA), perfluorooctane sulfonic (PFOS), perfluorooctanoic (PFOA), methyl-perfluorooctane sulfonamide acetic acid (Me-PFOSA-AcOH), perfluorohexanesulfonic (PFHxS), perfluorodecanoic (PFDeA), and perfluoroundecanoic (PFUdA) acid. Key outcomes were plasma glucose, insulin, C-peptide, insulin-like growth factor 1 (IGF-1), adiponectin, leptin, triglycerides, free fatty acids, total cholesterol, high-density lipoprotein (HDL) cholesterol, C-reactive protein, tumor necrosis factor alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1), and interleukin 6. We calculated homeostatic model assessment for insulin resistance (HOMA-IR), low-density lipoprotein (LDL) cholesterol, and very low-density lipoprotein (VLDL). We evaluated associations of PFAS with each metabolic/inflammatory biomarker individually using covariate-adjusted linear regression and jointly using quantile-based g-computation.

RESULTS

In linear regression, all PFAS (except Me-PFOSA-AcOH) were negatively associated with insulin, HOMA-IR, and leptin, whereas all PFAS were positively associated with HDL cholesterol. We also observed negative associations of some PFAS with TNF-α and MCP-1; positive associations with adiponectin and total cholesterol also emerged. Additionally, PFOS was positively, whereas Me-PFOSA-AcOH was negatively, associated with triglycerides and VLDL. Each 25% increase in the PFAS mixture was associated with -31.3% lower insulin (95%CI: -45.8, -12.9), -31.9% lower HOMA-IR (95%CI: -46.4, -13.4), and -9.4% lower leptin (95%CI: -17.3, -0.8), but 7.4% higher HDL cholesterol (95%CI: 4.6, 10.3). For most outcomes, the major contributors to the PFAS mixture often differed compared to single-PFAS analyses.

IMPLICATIONS

Individual and joint PFAS exposures were associated with markers of maternal metabolism and inflammation in pregnancy. Further investigation is needed to elucidate possible mechanisms and consequences of these findings.

Environmentally related microcystin-LR-induced ovarian dysfunction via the CCL2-CCR10 axis in mice ameliorated by dietary mulberry

Microcystin-LR (MC-LR) is a reproductive toxin produced by cyanobacteria in the aquatic environment and can be ingested by humans through drinking water and the food chain, posing a threat to human reproductive health. However, the toxic mechanisms and prospective interventions for MC-LR-induced ovarian dysfunction at environmental doses are unknown. The mulberry fruit is a traditional natural product of plant origin, with various pharmacological effects, such as antioxidant and anti-inflammatory effects. Here, mice were exposed to MC-LR (10, 100 μg/L) in drinking water for 90 days, during which mice were gavage 600 mg/kg/week of mulberry fruit extract (MFE). It was found that MC-LR can accumulate in mouse ovaries, causing sexual hormone disturbance, inflammatory infiltration, and ovarian pathological damage. Results from RNA-seq were shown that CCL2, a chemokine associated with inflammatory response, was significantly increased in mouse ovary after MC-LR exposure. Further investigation revealed that MC-LR exposure aggravates apoptosis of granulosa cells via the CCL2-CCR10 axis-mediated Jak/Stat pathway. Importantly, MFE can significantly ameliorate these ovarian dysfunction phenotypes by inhibiting the activation of the CCL2-CCR10 axis. This study broadened new insights into the ovarian toxicity of MC-LR and clarified the pharmacological effects of mulberry fruit on ovarian function protection.

Investigating the progression of preeclampsia through a comprehensive analysis of genes associated with per- and polyfluoroalkyl substances

Per- and Polyfluoroalkyl Substances (PFAS) are synthetic chemicals utilized in the production of various products that possess water and dirt-repellent properties. Exposure to PFAS has been linked to numerous diseases, such as cancer and preeclampsia (PE). However, whether PFAS contributes to the advancement of PE remains uncertain. In this study, we conducted an extensive bioinformatics analysis using the Comparative Toxicogenomics Database (CTD) and Gene Expression Omnibus (GEO) databases, leading us to discover a connection between PE and four specific PFAS. Moreover, further examination revealed that six genes associated with PFAS exhibited significant diagnostic potential for individuals with PE. By employing receiver operating characteristic (ROC) curves, our PFAS-related gene-based nomogram model demonstrated outstanding predictive efficacy for diagnosing PE. Immune infiltration analysis showed that six PFAS-related genes were significantly associated with the level of immune cell infiltration. The expression of PFAS-related genes in PE patients was confirmed by collecting clinical samples. This research has offered fresh perspectives on comprehending the impact of PFAS on PE, drawing attention to the connection between environmental factors and the risks and development of PE.

First trimester plasma PER- AND Polyfluoroalkyl Substances (PFAS) and blood pressure trajectories across the second and third trimesters of pregnancy

BACKGROUND

Evidence suggests that exposure to per- and polyfluoroalkyl substances (PFAS) increases risk of high blood pressure (BP) during pregnancy. Prior studies did not examine associations with BP trajectory parameters (i.e., overall magnitude and velocity) during pregnancy, which is linked to adverse pregnancy outcomes.

OBJECTIVES

To estimate associations of multiple plasma PFAS in early pregnancy with BP trajectory parameters across the second and third trimesters. To assess potential effect modification by maternal age and parity.

METHODS

In 1297 individuals, we quantified six PFAS in plasma collected during early pregnancy (median gestational age: 9.4 weeks). We abstracted from medical records systolic BP (SBP) and diastolic BP (DBP) measurements, recorded from 12 weeks gestation until delivery. BP trajectory parameters were estimated via Super Imposition by Translation and Rotation modeling. Subsequently, Bayesian Kernel Machine Regression (BKMR) was employed to estimate individual and joint associations of PFAS concentrations with trajectory parameters - adjusting for maternal age, race/ethnicity, pre-pregnancy body mass index, income, parity, smoking status, and seafood intake. We evaluated effect modification by age at enrollment and parity.

RESULTS

We collected a median of 13 BP measurements per participant. In BKMR, higher concentration of perfluorooctane sulfonate (PFOS) was independently associated with higher magnitude of overall SBP and DBP trajectories (i.e., upward shift of trajectories) and faster SBP trajectory velocity, holding all other PFAS at their medians. In stratified BKMR analyses, participants with ≥ 1 live birth had more pronounced positive associations between PFOS and SBP velocity, DBP magnitude, and DBP velocity - compared to nulliparous participants. We did not observe significant associations between concentrations of the overall PFAS mixture and either magnitude or velocity of the BP trajectories.

CONCLUSION

Early pregnancy plasma PFOS concentrations were associated with altered BP trajectory in pregnancy, which may impact future cardiovascular health of the mother.

Association between prenatal perfluorinated compounds exposure and risk of pregnancy complications: A meta-analysis

BACKGROUND AND OBJECTIVE

Per- and polyfluoroalkyl substances (PFASs) have been shown to be persistent and bioaccumulative. An elevated danger of pregnancy complications perhaps connected with exposure to PFASs, but the potential effects remain elusive. The objective of this study is to investigate the possible association between PFASs exposure and pregnancy complications, drawing upon existing evidence.

METHODS

Electronic databases of PubMed, Qvid Medline, Embase, and Web of Science were searched thoroughly to identify eligible research published prior to November 28, 2023, examining the relationship between PFASs and pregnancy-related complications. To evaluate the quality of observational studies incorporated into the article, the Strengthening Reporting of Observational Studies in Epidemiology (STROBE) tool was utilized. The main outcomes assessed in this study included gestational diabetes mellitus (GDM), hypertensive disorders of pregnancy (HDP), gestational hypertension (GH), and preeclampsia (PE).

RESULTS

Twenty-five relevant studies involving 30079 participants were finally selected from four databases. The combined estimates indicate that prenatal exposure to perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorobutane sulfonic acid (PFBS), and perfluoroenanthic acid (PFHpA) is associated with gestational diabetes mellitus (GDM) (PFOA: OR = 1.45, 95%CI: 1.07-1.94, P = 0.015; PFHxS: OR = 1.16, 95%CI: 1.00-1.36, P = 0.055; PFBS: OR = 1.44, 95%CI: 1.16-1.79, P = 0.001; PFHpA: OR = 1.41, 95%CI: 1.10-1.82, P = 0.008). The exposure to PFBS is positively associated with HDP (OR = 1.27, 95%CI: 1.14-1.41, P < 0.001), while both PFOA and PFHpA demonstrate statistically significant positive correlations with GH (PFOA: OR = 1.09, 95%CI: 1.00-1.19, P = 0.049; PFHpA: OR = 1.43, 95%CI: 1.15-1.78, P = 0.001). Negative correlations were observed for prenatal perfluorododecanoic acid (PFDoA) exposure and GH (OR = 0.71, 95%CI: 0.57-0.87, P = 0.001). However, no compelling evidence was identified to link PFASs exposure with the risk of PE.

CONCLUSION

According to the meta-analysis findings, exposure to PFASs may be linked to GDM, HDP, and GH, but it does not significantly raise the risk of PE alone. Further research with larger sample size is required to verify this potential association and explore the biological mechanisms.

Perfluorooctanoic acid induces transcriptomic alterations in second trimester human cytotrophoblasts

Poly- and perfluroroalkylated substances (PFAS) are a major class of surfactants used in industry applications and consumer products. Despite efforts to reduce the usage of PFAS due to their environmental persistence, compounds such as perfluorooctanoic acid (PFOA) are widely detected in human blood and tissue. Although growing evidence supports that prenatal exposures to PFOA and other PFAS are linked to adverse pregnancy outcomes, the target organs and pathways remain unclear. Recent investigations in mouse and human cell lines suggest that PFAS may impact the placenta and impair trophoblast function. In this study, we investigated the effects of PFOA on cytotoxicity and the transcriptome in cultured second trimester human cytotrophoblasts (CTBs). We show that PFOA significantly reduces viability and induces cell death at 24 h, in a concentration-dependent manner. At subcytotoxic concentrations, PFOA impacted expression of hundreds of genes, including several molecules (CRH, IFIT1, and TNFSF10) linked with lipid metabolism and innate immune response pathways. Furthermore, in silico analyses suggested that regulatory factors such as peroxisome proliferator-activated receptor-mediated pathways may be especially important in response to PFOA. In summary, this study provides evidence that PFOA alters primary human CTB viability and gene pathways that could contribute to placental dysfunction and disease.

PFOS Impairs Mitochondrial Biogenesis and Dynamics and Reduces Oxygen Consumption in Human Trophoblasts

Perfluorooctane sulfonate (PFOS), a synthetic chemical used in various commercial applications and industrial settings, has led to contamination of drinking water and has been detected in the bloodstream of pregnant women with gestational complications. Recent investigations have indicated that PFOS disrupts placental function; however, the mechanism remains elusive. Given the significant abundance of mitochondria in the placenta, which play a pivotal role in fulfilling the heightened energy requirements of pregnancy, our research aimed to examine the repercussions of PFOS exposure on mitochondrial dynamics within placental trophoblasts. Specifically, human trophoblasts (HTR-8/SVneo) were exposed to environmentally relevant concentrations of PFOS ranging from 0.1 to 50 μM for 48 hours. Findings revealed that PFOS exposure elicited a concentration-dependent decrease in basal, maximal, and ATP-linked respiration. PFOS inhibited the activity of electron transport complexes I, II, and III, resulting in diminished ATP production. Furthermore, PFOS reduced mitochondrial DNA copy number, indicating less mitochondrial content. Concurrently, there was a downregulation in the expression of mitochondrial biogenesis-related genes, including PGC-1α, NRF1, and NRF2. Notably, PFOS perturbed mitochondrial dynamics by suppressing the expression of fission-related genes (FIS1 and DRP1) and fusion-related genes (MFN1 and MFN2). In summary, our findings suggest that PFOS exposure leads to a decline in mitochondrial content and compromises the bioenergetic capacity of trophoblasts by impairing cellular respiration. This reduction in mitochondrial biogenesis and alterations in fission/fusion dynamics induced by PFOS may contribute to mitochondrial dysfunction in trophoblasts. Consequently, strategies that preserve mitochondrial function in trophoblasts may mitigate PFOS-induced impairment of placental energy metabolism.

Long-chain perfluoroalkyl carboxylates induce cytoskeletal abnormalities and activate epithelial-mesenchymal transition in both renal cell carcinoma 3D cultures and Caki-1 xenografted mouse model

Exposure to perfluorooctanoate (PFOA; a type of perfluoroalkyl carboxylates [PFACs]) may be correlated with the incidence of kidney cancer in individuals exposed to high levels of PFOA. However, mechanistic studies on the influence of PFACs on renal cell carcinoma (RCC) development are lacking. We explored the effects of five types of PFACs on RCC using in vitro and in vivo models to fill this knowledge gap and provide information for environmental/usage regulations. Using 2D/3D cultures of Caki-1 cells, a human clear cell RCC line, we examined the effects of short-chain (SC) PFACs and long-chain (LC) PFACs on RCC physio/pathological markers, including the cytoskeleton, epithelial-mesenchymal transition (EMT)-related proteins, and Na+/K+-ATPase. We also administered three different PFACs orally to mice harboring Caki-1 xenografts to assess the impact of these compounds on engrafted RCC in vivo. Compared with the effects of SCPFACs, mice with Caki-1 xenografts treated with LCPFACs showed increased EMT-related protein expression and exhibited liver toxicity. Therefore, LCPFACs induced EMT, influencing cancer metastasis activity, and displayed higher toxicity in vivo compared with SCPFACs. These findings improve our understanding of the effects of PFACs on RCC development and their corresponding in vivo toxicity, which is crucial for regulating these substances to protect public health.

Effects of Xenobiotic Compounds on Preeclampsia and Potential Mechanisms

Preeclampsia (PE) refers to a disease with new hypertension and albuminuria or other end-organ damage after 20 weeks of pregnancy. As a major complication of pregnancy, PE can increase the morbidity and mortality of pregnant women and fetuses and cause serious social burden. Recently, it has been found that exposure to xenobiotic compounds, especially endocrine disruptors in the environment, may contribute to the development of PE. However, the underlying mechanism is still unclear. It is generally believed that PE is related to placental dysplasia, spiral artery remodelling failure, oxidative stress, etc. Therefore, in order to better prevent the occurrence of PE and reduce the damage and impact on mother and fetus, this paper reviews the role and potential mechanism of PE induced by exogenous chemicals and provides an outlook on the environmental etiology of PE.

Prenatal exposure to per- and polyfluoroalkyl substances and pregnancy outcome in Austria

Per- and polyfluoroalkyl substances (PFAS) are a large group of persistent industrial chemicals that can harm reproductive health. PFAS levels were analysed to determine the current sources of exposure and possible associations between prenatal PFAS exposure and adverse pregnancy outcome. Samples from 136 mother-newborn pairs recruited between 2017 and 2019 were analysed for the presence of 31 target PFAS in maternal serum, umbilical cord serum, and placental tissue by high-performance liquid chromatography coupled to a tandem mass spectrometer. Questionnaires and medical records were used to survey sources of exposure and pregnancy outcome, including small for gestational age (SGA), fetal growth restriction (FGR), preeclampsia (PE), preterm birth, large for gestational age (LGA) and gestational diabetes mellitus (GDM). Data were analysed for individual PFAS and sum4PFAS (sum of perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexane sulfonate (PFHxS), and perfluorooctane sulfonate (PFOS) serum levels) in logistic regression analyses and categorical regression analyses. Compared to data from a previous Viennese study in 2010-12, sum4PFAS levels were generally lower. Sum4PFAS serum levels of three women (2.2%) exceeded 6.9 µg/L, a level that corresponds to the recently established tolerable weekly intake (TWI) of EFSA for nursing mothers aged 35 years; in the 2010/2012 study it was 13.6%. The large contribution of unidentified extractable organofluorine (EOF) fractions to total PFAS exposure is a concern. Study site, mean maternal corpuscular hemoglobin (MCH), use of facial lotion, and owning upholstered furniture were significantly influencing maternal exposure. While no effect of sum4PFAS on pregnancy outcome could be detected, we found highest placental PFDA levels in SGA births. PFHxS levels in umbilical cord and placenta were highest in preterm births. Further studies are needed to elucidate the relationship of prenatal PFAS exposure and pregnancy outcome, in particular to confirm whether and how placental PFDA levels may contribute to an increased risk for SGA.

Poly- and Perfluoroalkyl Substances Induce Immunotoxicity via the TLR Pathway in Zebrafish: Links to Carbon Chain Length

Previous studies have reported the immunotoxicity of per- and polyfluoroalkyl substances (PFASs), but it remains a significant challenge to assess over 10,000 distinct PFASs registered in the distributed structure-searchable toxicity (DSSTox) database. We aim to reveal the mechanisms of immunotoxicity of different PFASs and hypothesize that PFAS immunotoxicity is dependent on the carbon chain length. Perfluorobutanesulfonic acid (PFBA), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) representing different carbon chain lengths (4-9) at environmentally relevant levels strongly reduced the host's antibacterial ability during the zebrafish's early-life stage. Innate and adaptive immunities were both suppressed after PFAS exposures, exhibiting a significant induction of macrophages and neutrophils and expression of immune-related genes and indicators. Interestingly, the PFAS-induced immunotoxic responses were positively correlated to the carbon chain length. Moreover, PFASs activated downstream genes of the toll-like receptor (TLR), uncovering a seminal role of TLR in PFAS immunomodulatory effects. Myeloid differentiation factor 88 (MyD88) morpholino knock-down experiments and MyD88 inhibitors alleviated the immunotoxicity of PFASs. Overall, the comparative results demonstrate differences in the immunotoxic responses of PFASs due to carbon chain length in zebrafish, providing new insights into the prediction and classification of PFASs mode of toxic action based on carbon chain length.

Unveiling Distribution of Per- and Polyfluoroalkyl Substances in Matched Placenta-Serum Tetrads: Novel Implications for Birth Outcome Mediated by Placental Vascular Disruption

The placenta is pivotal for fetal development and maternal-fetal transfer of many substances, including per- and polyfluoroalkyl substances (PFASs). However, the intraplacental distribution of PFASs and their effects on placental vascular function remain unclear. In this study, 302 tetrads of matched subchorionic placenta (fetal-side), parabasal placenta (maternal-side), cord serum, and maternal serum samples were collected from Guangzhou, China. Eighteen emerging and legacy PFASs and five placental vascular biomarkers were measured. Results showed that higher levels of perfluorooctanoic (PFOA), perfluorooctane sulfonic acid (PFOS), and chlorinated polyfluorinated ether sulfonic acids (Cl-PFESAs) were detected in subchorionic placenta compared to parabasal placenta. There were significant associations of PFASs in the subchorionic placenta, but not in the serum, with placental vascular biomarkers (up to 32.5%) and lower birth size. Birth weight was negatively associated with PFOA (β: -103.8, 95% CI: -186.3 and -21.32) and 6:2 Cl-PFESA (β: -80.04, 95% CI: -139.5 and -20.61), primarily in subchorionic placenta. Mediation effects of altered placental angiopoietin-2 and vascular endothelial growth factor receptor-2 were evidenced on associations of adverse birth outcomes with intraplacental PFOS and 8:2 Cl-PFESA, explaining 9.5%-32.5% of the total effect. To the best of our knowledge, this study is the first to report on differential intraplacental distribution of PFASs and placental vascular effects mediating adverse birth outcomes and provides novel insights into the placental plate-specific measurement in PFAS-associated health risk assessment.

High-throughput screening of toxicants that modulate extravillous trophoblast migration

Migration and subsequent invasion of extravillous trophoblasts into the uterus is essential for proper formation of the placenta. Disruption of these processes may result in poor pregnancy outcomes including preeclampsia, placenta accreta, fetal growth restriction, or fetal death. Currently, there are several methods for quantifying cell migration and invasion in vitro, each with limitations. Therefore, we developed a novel, high-throughput method to screen chemicals for their ability to alter human trophoblast migration. Human HTR8/SVneo trophoblast cells were cultured in Oris™ cell migration plates containing stopper barriers. After EVT cells attached and chemicals were added to media, stoppers were removed thereby creating a cell-free detection zone for migration. Entry of trophoblasts into this zone was monitored through imaging every 6 h and used to calculate a relative cell density. Chemicals known to increase (epidermal growth factor) and decrease (pertussis toxin and cadmium) trophoblast migration were used to validate this in vitro method. Next, a panel of environmental chemicals including bisphenols, mycoestrogens, and flame retardants, were screened for their ability to alter trophoblast invasion. In conclusion, a real-time method to track extravillous trophoblast migration offers potential for screening contaminants as placental toxicants.

In utero exposure to per-/polyfluoroalkyl substances (PFASs): Preeclampsia in pregnancy and low birth weight for neonates

Per-/polyfluoroalkyl substances (PFASs) have been linked to preeclampsia with inconsistent directions for outcomes. However, information regarding the joint effects of PFASs mixtures on preeclampsia as well as their associations with the low birth weight (LBW) and small for gestational age (SGA) is nascent. The present study included 82 women with preeclampsia and 169 healthy participants from Hangzhou, China. Fifteen PFASs were analyzed in maternal serum before delivery. PFOA and 6:2Cl-PFESA were associated with higher incidence of preeclampsia both linearly and by tertile. Each log-unit increase in serum PFOA (OR:5.29, 95% CI: 1.05, 26.7, p = 0.044) and 6:2 Cl-PFESA (OR:1.02, 95%CI: 1.00, 1.48, p = 0.045) concentrations were associated with increased risks of preeclampsia. These effects were more profound among primiparous women carrying female fetuses. Both PFOA and PFUnDA concentrations were significantly associated with higher odds of early-onset preeclampsia, but the associations tended to be null for late-onset. In addition, each logarithmic increment in PFOA concentrations were significantly associated with a 0.262 and 0.224 mmHg increase in systolic (95% CI: 0.147, 0.377) and diastolic (95% CI: 0.133, 0.314) blood pressures. Using Bayesian kernel machine regressions (BKMR), the overall effects of PFASs mixture concentrations on preeclampsia showed an increasing trend, with PFOA being the largest contributor. With regard to birth weight, the Cox proportional hazards model indicated that significantly higher risks of the LBW were associated with preeclampsia than normal pregnancy (OR: 4.56, 95% CI: 2.44, 6.68, p = 0.000). Increased LBW risks were found for the higher PFOA exposure both linearly and by tertile. Besides, serum PFOA and PFUnDA concentrations were significantly associated with higher odds of SGA development. Nevertheless 4:2 FTS and ADONA were inversely associated with LBW and SGA incidences. Further adverse birth outcomes should be explored to elucidate the health implications of PFASs exposure and preeclampsia development.

Exposure to endocrine-disrupting chemicals and risk of gestational hypertension and preeclampsia: A systematic review and meta-analysis

Prenatal exposure to endocrine-disrupting chemicals has been linked to gestational hypertension (GH) and preeclampsia (PE). However, the results were conflicting and inconclusive. We conducted a systematic review and meta-analysis for an overview of these relationships. We searched PubMed, and Google Scholar for studies investigating bisphenol A, phthalates, and per or poly-fluoroalkyl substances and GH or PE. Pooled odds ratio (OR) with a 95% confidence interval (CI) were calculated for risk estimate using the generic inverse variance method. A total of 14 studies were included in the present analysis. The pooled results demonstrated that perfluorooctanoic acid (PFOA, OR:1.20, 95% CI: 1.04, 1.39), perfluoro octane sulfonic acid (PFOS, (OR:1.23, 95% CI: 1.10, 1.38), and perfluononanoic acid (PFNA, OR:1.20, 95% CI: 1.03, 1.40) were significantly associated with an increased risk of PE. There was no significant association observed with perfluoro hexane sulfonic acid (PFHxS), perfluoro decanoic acid (PFDA), perfluoro heptanoic acid (PFHpA), and perfluoro undecanoic acid (PFUnDA) and PE. For GH, a statistically significant positive association was found with PFOA (OR:1.18, 95% CI: 1.01, 1.39) and PFHxS (OR:1.15, 95% CI: 1.02, 1.29). Among various phthalates analysed only mono-ethyl phthalate (MEP, OR:1.37, 95% CI: 1.11, 1.70) showed an association with GH. From our analysis, bisphenol A exposure during pregnancy did not show a significant association with the risk of PE. Our findings indicated that exposure to PFASs such as PFOA, PFOS, and PFNA during pregnancy is associated with an increased risk of PE and PFOA and PFHxS with GH. We also found that MEP was associated with GH. Most of the results were unstable in sensitivity analysis. Since most of these associations have limited evidence, more research is needed to confirm these findings.

Blood transcriptome responses to PFOA and GenX treatment in the marsupial biomedical model Monodelphis domestica

Introduction: Perfluoroalkyl and poly-fluoroalkyl substances (PFASs) are widely used in industrial and consumer products. Due to their environmental persistence and bioaccumulation, PFASs can be found in the blood of humans and wild animals all over the world. Various fluorinated alternatives such as GenX have been developed to replace the long-chain PFASs, but there is limited information about their potential toxicity. Methods:The current study developed blood culture protocols to assess the response to toxic compounds in the marsupial, Monodelphis domestica. After whole-blood culture conditions were tested and optimized, changes in gene expression in response to PFOA and GenX treatment were assessed. Results: More than 10,000 genes were expressed in the blood transcriptomes with and without treatment. Both PFOA and GenX treatment led to significant changes in the whole blood culture transcriptomes. A total of 578 and 148 differentially expressed genes (DEGs) were detected in the PFOA and GenX treatment groups, 32 of which overlapped. Pathway enrichment analysis revealed that DEGs involved in developmental processes were upregulated after PFOA exposure, while those enriched for metabolic and immune system processes were downregulated. GenX exposure upregulated genes associated with fatty acid transport pathways and inflammatory processes, which is consistent with previous studies using rodent models. Discussion: To our knowledge, this study is the first to investigate the effect of PFASs in a marsupial model. The findings provide supportive evidence for significant transcriptomic alterations, suggesting that this mammalian model may provide a mechanism for exploring the potential toxicity of PFOA and GenX.

Early-pregnancy plasma per- and polyfluoroalkyl substance (PFAS) concentrations and hypertensive disorders of pregnancy in the Project Viva cohort

BACKGROUND

Hypertensive disorders of pregnancy (HDP), defined here as hypertensive disorders with onset in pregnancy (i.e., gestational hypertension, preeclampsia, and preeclampsia superimposed on chronic hypertension), affect up to 10% of pregnancies in the United States and are associated with substantial maternal and neonatal morbidity and mortality. Per- and polyfluoroalkyl substances (PFAS) are associated with adverse cardiometabolic outcomes during pregnancy, but associations between PFAS and HDP are inconsistent and joint effects of PFAS mixtures have not been evaluated.

METHODS

We studied 1,558 pregnant individuals from the Project Viva cohort, recruited during 1999-2002. We quantified concentrations of eight PFAS in plasma samples (median 9.7 weeks of gestation). Using clinical records, we calculated trimester-specific mean systolic (SBP) and diastolic (DBP) blood pressure and categorized HDP status [no HDP (normotensive & chronic hypertension), gestational hypertension, preeclampsia]. We estimated associations of individual PFAS with HDP using multinomial logistic regression and estimated associations with blood pressure using linear regression. We used Bayesian kernel machine regression (BKMR) and quantile g-computation to assess joint effects of the PFAS mixture on HDP and blood pressure measures.

RESULTS

Four percent of participants developed preeclampsia and 7% developed gestational hypertension. We observed higher odds of gestational hypertension, but not preeclampsia, per doubling of perfluorooctanoate (PFOA) [OR = 1.51 (95% confidence interval: 1.12, 2.03)], perfluorooctane sulfonate (PFOS) [OR = 1.38 (1.04, 1.82)], and perfluorohexane sulfonate [OR = 1.28 (1.06, 1.54)] concentrations. We observed higher mean DBP per doubling of PFOA [2nd trimester (T2): 0.39 mmHg (-0.01, 0.78); 3rd trimester (T3): 0.56 mmHg (0.14, 0.98)] and PFOS [T2: 0.46 mmHg (0.11, 0.82); T3: 0.43 mmHg (0.05, 0.80)]. The PFAS mixture was positively associated with odds of gestational hypertension [75th vs. 50th percentile: OR = 1.14 (95% credible interval:1.03, 1.25), BKMR] and mean DBP [T2 = 0.17 mmHg (-0.06, 0.40); T3 = 0.22 mmHg (-0.03, 0.48), BKMR].

CONCLUSIONS

These findings suggest that exposure to certain PFAS may increase the odds of gestational hypertension during pregnancy, with potential implications for subsequent maternal and child health outcomes.

Concentrations of per- and polyfluoroalkyl substances (PFAS) in human placental tissues and associations with birth outcomes

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants commonly detected in human serum. Previous studies have observed associations between maternal serum PFAS and adverse pregnancy and birth outcomes such as lower birth weight or pre-eclampsia; however, few studies have explored these associations with birth outcomes and placental tissue PFAS concentration. The placenta is a vital contributor to a healthy pregnancy and may be involved in the mechanism of PFAS reproductive toxicity. Our goal was to measure placental PFAS concentrations and examine associations with birth outcomes (e.g., birth weight, gestational duration). Placenta samples (n = 120) were collected during delivery from women enrolled in the Healthy Pregnancy, Healthy Baby cohort (HPHB) in Durham, North Carolina. All placenta samples contained detectable PFAS, with perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) being the most abundant and most frequently detected (all >96% detection frequency). While placental PFAS concentrations did not differ by infant sex, higher PFAS levels were observed in placenta from nulliparous women, suggesting that parity influences the accumulation of PFAS in the placenta. We used linear regression models to examine associations between placental PFAS and birth outcomes. After adjustment for parity, tobacco use, maternal age, and maternal race, we found that placental PFOS was associated with lower birth weight for gestational age in male infants and higher birth weight for gestational age in female infants. Similar findings were seen for PFNA for birth weight for gestational age. These differences in birth outcomes based on infant sex highlight a need to explore mechanistic differences in PFAS toxicity during gestation for male and female infants.

Perfluorooctanoic acid exposure increases both proliferation and apoptosis of human placental trophoblast cells mediated by ER stress-induced ROS or UPR pathways

Perfluorooctanoate acid (PFOA) is a highly persistent and widespread chemical in the environment. PFOA serum levels in pregnant women are positively associated with an increased risk of placenta-related disorders. However, the mechanism of PFOA cytotoxicity involved in placental cells and cellular responses such as ER stress remains poorly understood. In this study, we studied the cellular toxicity of PFOA with a focus on proliferation and apoptosis in a human placental trophoblast cell line. Cell viability, number, apoptosis, stress response, activation of the involved signaling pathways were assessed. Our results showed PFOA affected cell viability, proliferation and also resulted in apoptosis. Besides, both pro-proliferation and pro-apoptosis effects were attenuated by endoplasmic reticulum (ER) stress inhibitors. Further experiments demonstrated that two different signaling pathways were activated by PFOA-induced ER stress and involved in PFOA toxicity: the reactive oxygen species (ROS)-dependent ERK signaling triggered trophoblast proliferation, while the ATF4-dependent C/EBP homologous protein (CHOP) signaling was the trigger of apoptosis. We conclude that PFOA-induced ER stress is the trigger of proliferation and apoptosis of trophoblast via ROS or UPR signaling pathway, which leads to the altered balance critical to the normal development and function of the placenta.

Prenatal Exposure to an EDC Mixture, NeuroMix: Effects on Brain, Behavior, and Stress Responsiveness in Rats

Humans and wildlife are exposed to endocrine-disrupting chemicals (EDCs) throughout their lives. Environmental EDCs are implicated in a range of diseases/disorders with developmental origins, including neurodevelopment and behavior. EDCs are most often studied one by one; here, we assessed outcomes induced by a mixture designed to represent the real-world situation of multiple simultaneous exposures. The choice of EDCs, which we refer to as “NeuroMix,” was informed by evidence for neurobiological effects in single-compound studies and included bisphenols, phthalates, vinclozolin, and perfluorinated, polybrominated, and polychlorinated compounds. Pregnant Sprague Dawley rats were fed the NeuroMix or vehicle, and then offspring of both sexes were assessed for effects on postnatal development and behaviors and gene expression in the brain in adulthood. In order to determine whether early-life EDCs predisposed to subsequent vulnerability to postnatal life challenges, a subset of rats were also given a stress challenge in adolescence. Prenatal NeuroMix exposure decreased body weight and delayed puberty in males but not females. In adulthood, NeuroMix caused changes in anxiety-like, social, and mate preference behaviors only in females. Effects of stress were predominantly observed in males. Several interactions of NeuroMix and stress were found, especially for the mate preference behavior and gene expression in the brain. These findings provide novel insights into how two realistic environmental challenges lead to developmental and neurobehavioral deficits, both alone and in combination, in a sex-specific manner.

Extravillous trophoblast migration and invasion: Impact of environmental chemicals and pharmaceuticals

During pregnancy, the migration and invasion of extravillous trophoblasts (EVTs) into the maternal uterus is essential for proper development of the placenta and fetus. During the first trimester, EVTs engraft and remodel maternal spiral arteries allowing for efficient blood flow and the transfer of essential nutrients and oxygen to the fetus. Aberrant migration of EVTs leading to either shallow or deep invasion into the uterus has been implicated in a number of gestational pathologies including preeclampsia, fetal growth restriction, and placenta accreta spectrum. The migration and invasion of EVTs is well-coordinated to ensure proper placentation. However, recent data point to the ability of xenobiotics to disrupt EVT migration. These xenobiotics include heavy metals, endocrine disrupting chemicals, and organic contaminants and have often been associated with adverse pregnancy outcomes. In most instances, xenobiotics appear to reduce EVT migration; however, there are select examples of enhanced motility after chemical exposure. In this review, we provide an overview of the 1) current experimental approaches used to evaluate EVT migration and invasion in vitro, 2) ability of environmental chemicals and pharmaceuticals to enhance or retard EVT motility, and 3) signaling pathways responsible for altered EVT migration that are sensitive to disruption by xenobiotics.

The use of in vitro methods in assessing human health risks associated with short-chain perfluoroalkyl and polyfluoroalkyl substances (PFAS)

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a large class of industrial chemicals with a ubiquitous and persistent presence in the environment. Of the thousands of PFAS used by consumers and industry, very few have been thoroughly characterized for potential adverse effects. This is especially true for the novel short-chain (C < 8) alternatives that replaced legacy PFAS. Perfluoroalkyl and polyfluoroalkyl substances have revealed inconsistencies in the toxicokinetics predicted by animal models and empirical findings in humans. To adequately assess the possible health effects of short-chain PFAS, there is a need for robust aggregated data sets on the mechanistic underpinnings and physiochemical properties of these alternatives. Acquiring relevant data on the health effects of short-chain PFAS can be achieved through high-throughput methods supported by in vitro human cell-based models. This review briefly summarizes some of the toxicity data obtained using human cells in vitro, discusses the advantages and limitations of cell-based models, and provides insights on potential solutions to challenges presented with the use of these methods for use in safety assessments.

Fetoplacental vasculature as a model to study human cardiovascular endocrine disruption

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

Per- and polyfluoroalkyl substances exposure during pregnancy and adverse pregnancy and birth outcomes: A systematic review and meta-analysis

BACKGROUND

Exposure to per- and polyfluoroalkyl substances (PFAS) during pregnancy has been suggested to be associated with adverse pregnancy and birth outcomes; however, the findings have been inconsistent. We aimed to conduct a systematic review and meta-analysis to provide an overview of these associations.

METHODS

The online databases PubMed, EMBASE and Web of Science were searched comprehensively for eligible studies from inception to February 2021. Odds ratios (ORs) and 95% confidence intervals (CIs) were pooled using random- or fixed-effects models, and dose-response meta-analyses were also conducted when possible.

FINDINGS

A total of 29 studies (32,905 participants) were included. The pooled results demonstrated that perfluorooctane sulfonate (PFOS) exposure during pregnancy was linearly associated with increased preterm birth risk (pooled OR per 1-ng/ml increase: 1.01, 95% CIs: 1.00-1.02, P = 0.009) and perfluorononanoate (PFNA) and perfluorooctanoate (PFOA) exposure showed inverted U-shaped associations with preterm birth risk (P values for the nonlinear trend: 0.025 and 0.030). Positive associations were also observed for exposure to perfluorodecanoate (PFDA) and miscarriage (pooled OR per 1-ng/ml increase: 1.87, 95% CIs: 1.15-3.03) and PFOS and preeclampsia (pooled OR per 1-log increase: 1.27, 95% CIs: 1.06-1.51), whereas exposure to perfluoroundecanoate (PFUnDA) was inversely associated with preeclampsia risk (pooled OR per 1-log increase: 0.81, 95% CIs: 0.71-0.93). Based on individual evidence, detrimental effects were observed between PFDA exposure and small for gestational age and between PFOA and PFOS and intrauterine growth restriction. No significant associations were found between pregnancy PFAS exposure and other adverse pregnancy outcomes (i.e., gestational diabetes mellitus, pregnancy-induced hypertension, low birth weight, and large and small for gestational age).

INTERPRETATION

Our findings indicated that PFOS, PFOA and PFNA exposure during pregnancy might be associated with increased preterm birth risk and that PFAS exposure might be associated with the risk of miscarriage and preeclampsia. Due to the limited evidence obtained for most associations, additional studies are required to confirm these findings.

Maternal Levels of Perfluoroalkyl Substances (PFAS) during Early Pregnancy in Relation to Preeclampsia Subtypes and Biomarkers of Preeclampsia Risk

BACKGROUND

Prenatal exposure to perfluoroalkyl substances (PFAS) has been previously associated with preeclampsia, although findings are mixed with respect to the direction and magnitude of effect. To our knowledge, no studies have examined associations between PFAS and preeclampsia subtypes, which may have distinct etiologies.

OBJECTIVE

We examined associations between PFAS, any preeclampsia diagnosis, and early- and late-onset preeclampsia. In addition, we estimated associations between PFAS and the angiogenic biomarkers soluble fms-like tyrosine kinase-1 (sFLT-1) and placental growth factor (PlGF), which provide an estimate of pro- and anti-angiogenic activity within the placenta.

METHODS

This case-control study (n = 75 cases, n = 75 controls) was sampled from the LIFECODES birth cohort. Nine legacy PFAS were quantified in maternal plasma from early pregnancy (median = 10 wk) and angiogenic biomarkers were quantified in maternal plasma from four study visits (median = 10, 18, 26, and 35 wk). Logistic regression was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) of the association between an interquartile range (IQR)-increase in PFAS and preeclampsia outcomes. Linear regression was used to estimate associations between an IQR-increase in PFAS and concentrations of angiogenic biomarkers.

RESULTS

Both perfluorodecanoic acid (OR = 1.64, 95% CI: 1.08, 2.47) and perfluorooctanesulfonic acid (OR = 1.60, 95% CI: 1.06, 2.43) were associated with higher odds of late-onset preeclampsia. Associations tended to be below the null for early-onset preeclampsia, although findings were imprecise. Few associations were noted between PFAS and angiogenic biomarkers.

DISCUSSION

Maternal PFAS concentrations were associated with higher odds of late-onset preeclampsia. Heterogeneity of preeclampsia should be considered in future studies because populations may have different distributions of disease subtypes. https://doi.org/10.1289/EHP9091.

Nitric oxide mediates disruption of human placental trophoblast invasion induced by perfluorobutane sulfonate

Perfluorobutane sulfonate (PFBS), an emerging pollutant, is associated with disruption of placental functions and adverse birth outcomes. However, the precise mechanism of this disruption remains unclear. Extravillous trophoblasts make up the majority of cells in the placenta, and have invasive abilities, which plays a critical role in a successful pregnancy. It has been reported that inducible nitric oxide (iNOS) and nitric oxide (NO) signaling is associated with trophoblast migration and invasion. In this study, PFBS exposure was found to enhance trophoblast invasion and increase matrix metalloproteinase 9 (MMP-9) levels. Additionally, PFBS upregulated iNOS levels and stimulated NO generation. iNOS inhibitor treatment attenuated the increased invasion of trophoblasts and MMP-9 expression induced by PFBS. Extracellular signal-regulated kinase (ERK) phosphorylation was also enhanced by PFBS exposure. In the presence of an ERK pathway inhibitor, however, the increases in trophoblast invasion, the induction of NO production, iNOS expression and MMP-9 expression induced by PFBS were attenuated. Taken together, these results suggest that iNOS/NO signaling is triggered by activation of the ERK signaling pathway, and that iNOS/NO signaling mediates PFBS-induced stimulation of trophoblast invasion.

PFOS Inhibited Normal Functional Development of Placenta Cells via PPARγ Signaling

Perfluorooctane sulfonic acid (PFOS), a persistent environmental pollutant, has adverse effects on gestation pregnancy. Peroxisome proliferator-activated receptor γ (PPARγ) is involved in angiogenesis, metabolic processes, anti-inflammatory, and reproductive development. However, the function of PPARγ in PFOS evoked disadvantageous effects on the placenta remain uncertain. Here, we explored the role of PPARγ in PFOS-induced placental toxicity. Cell viability, cell migration, angiogenesis, and mRNA expression were monitored by CCK-8 assay, wound healing assay, tube formation assay, and real-time PCR, respectively. Activation and overexpression of PPARγ were conducted by rosiglitazone or pcDNA-PPARγ, and inhibition and knockdown of PPARγ were performed by GW9662 or si-PPARγ. Results revealed that PFOS decreased cell growth, migration, angiogenesis, and increased inflammation in human HTR-8/SVneo and JEG-3 cells. Placenta diameter and fetal weight decreased in mice treated with PFOS (12.5 mg/kg). In addition, rosiglitazone or pcDNA-PPARγ rescued cell proliferation, migration, angiogenesis, and decreased inflammation induced by PFOS in HTR8/SVneo and JEG-3 cells. Furthermore, GW9662 or si-PPARγ exacerbated the inhibition of cell viability, migration, angiogenesis, and aggravated inflammation induced by PFOS in HTR-8/SVneo and JEG-3 cells. Meanwhile, the results of mRNA expression level were consistent with the cell representation. In conclusion, our findings revealed that PFOS induced placenta cell toxicity and functional damage through PPARγ pathway.

Considering environmental exposures to per- and polyfluoroalkyl substances (PFAS) as risk factors for hypertensive disorders of pregnancy

Hypertensive disorders of pregnancy (HDP), including preeclampsia and gestational hypertension, lead to significant maternal morbidity and in some cases, maternal mortality. Environmental toxicants, especially those that disrupt normal placental and endothelial function, are emerging as potential risk factors for HDP. Per- and polyfluoroalkyl substances (PFAS) are a large group of ubiquitous chemicals found in consumer products, the environment, and increasingly in drinking water. PFAS have been associated with a multitude of adverse health effects, including dyslipidemia, hypertension, and more recently, HDP. In this review, we present epidemiological and mechanistic evidence for the link between PFAS and HDP and recommend next steps for research and prevention efforts. To date, epidemiological studies have assessed associations between only ten of the thousands of PFAS and HDP. Positive associations between six PFAS (PFOA, perfluorooctanoic acid; PFOS, perfluorooctane sulfonic acid; PFHxS, perfluorohexane sulfonic acid; PFHpA, perfluoroheptanoic acid; PFBS, perfluorobutanesulfonic acid; and PFNA, perfluoronanoic acid) and risk for HDP have been reported in some, but not all, studies. PFAS disrupt placental and immune function, cause oxidative stress, and disrupt lipid metabolism. These physiological disruptions may be mechanisms through which PFAS can lead to HDP. Overall, limited epidemiological evidence and plausible mechanisms support PFAS as risk factors for HDP. More research is needed in diverse, well-powered cohorts that assess exposures to as many PFAS as possible. Such research should consider not only individual PFAS but also the totality of exposures to PFAS and other environmental chemicals. Pregnant women may be a group that is vulnerable to PFAS exposure, and as such HDP risk should be considered by policymakers setting PFAS exposure limits. In the interim, medical and public health professionals in regions with PFAS contamination could provide short-term solutions in the form of patient-level prevention, increased monitoring, and early intervention for HDP.

Exposure to toxic metals and per- and polyfluoroalkyl substances and the risk of preeclampsia and preterm birth in the United States: a review

Preeclampsia and preterm birth are among the most common pregnancy complications and are the leading causes of maternal and fetal morbidity and mortality in the United States. Adverse pregnancy outcomes are multifactorial in nature and increasing evidence suggests that the pathophysiology behind preterm birth and preeclampsia may be similar-specifically, both of these disorders may involve abnormalities in placental vasculature. A growing body of literature supports that exposure to environmental contaminants in the air, water, soil, and consumer and household products serves as a key factor influencing the development of adverse pregnancy outcomes. In pregnant women, toxic metals have been detected in urine, peripheral blood, nail clippings, and amniotic fluid. The placenta serves as a "gatekeeper" between maternal and fetal exposures, because it can reduce or enhance fetal exposure to various toxicants. Proposed mechanisms underlying toxicant-mediated damage include disrupted placental vasculogenesis, an up-regulated proinflammatory state, oxidative stressors contributing to prostaglandin production and consequent cervical ripening, uterine contractions, and ruptured membranes and epigenetic changes that contribute to disrupted regulation of endocrine and immune system signaling. The objective of this review is to provide an overview of studies examining the relationships between environmental contaminants in the US setting, specifically inorganic (eg, cadmium, arsenic, lead, and mercury) and organic (eg, per- and polyfluoroalkyl substances) toxicants, and the development of preeclampsia and preterm birth among women in the United States.

Per- and Polyfluoroalkyl Substance Toxicity and Human Health Review: Current State of Knowledge and Strategies for Informing Future Research

Reports of environmental and human health impacts of per- and polyfluoroalkyl substances (PFAS) have greatly increased in the peer-reviewed literature. The goals of the present review are to assess the state of the science regarding toxicological effects of PFAS and to develop strategies for advancing knowledge on the health effects of this large family of chemicals. Currently, much of the toxicity data available for PFAS are for a handful of chemicals, primarily legacy PFAS such as perfluorooctanoic acid and perfluorooctane sulfonate. Epidemiological studies have revealed associations between exposure to specific PFAS and a variety of health effects, including altered immune and thyroid function, liver disease, lipid and insulin dysregulation, kidney disease, adverse reproductive and developmental outcomes, and cancer. Concordance with experimental animal data exists for many of these effects. However, information on modes of action and adverse outcome pathways must be expanded, and profound differences in PFAS toxicokinetic properties must be considered in understanding differences in responses between the sexes and among species and life stages. With many health effects noted for a relatively few example compounds and hundreds of other PFAS in commerce lacking toxicity data, more contemporary and high-throughput approaches such as read-across, molecular dynamics, and protein modeling are proposed to accelerate the development of toxicity information on emerging and legacy PFAS, individually and as mixtures. In addition, an appropriate degree of precaution, given what is already known from the PFAS examples noted, may be needed to protect human health. Environ Toxicol Chem 2021;40:606-630. © 2020 SETAC.

Perfluoroalkyl Substances (PFAS) and Their Effects on the Placenta, Pregnancy, and Child Development: a Potential Mechanistic Role for Placental Peroxisome Proliferator-Activated Receptors (PPARs)

PURPOSE OF REVIEW

This review summarizes studies highlighting perfluoroalkyl substances (PFAS) and their effects on the placenta, pregnancy outcomes, and child health. It highlights human population-based associations as well as in vitro-based experimental data to inform an understanding of the molecular mechanisms underlying these health effects. Among the mechanisms by which PFAS may induce toxicity is via their interaction with the peroxisome proliferator-activated receptors (PPARs), nuclear receptors that regulate lipid metabolism and placental functions important to healthy pregnancies, as well as fetal and child development.

RECENT FINDINGS

In utero exposure to prevalent environmental contaminants such as PFAS is associated with negative health outcomes during pregnancy, birth outcomes, and later in life. Specifically, PFAS have been associated with increased incidence of gestational diabetes, childhood obesity, preeclampsia, and fetal growth restriction. In terms of placental molecular mechanisms underlying these associations, studies demonstrate that PFAS interfere with trophoblast lipid homeostasis, inflammation, and invasion. Moreover these effects could be mediated in part by the interaction between PFAS and PPARs, as well as other biological mechanisms. This review summarizes how PFAS, critical environmental contaminants, may contribute to diseases of pregnancy as well as early and later child health.

Exposure to perfluorobutane sulfonate and perfluorooctanesulfonic acid disrupts the production of angiogenesis factors and stress responses in human placental syncytiotrophoblast

Poly- and per-fluoroalkyl substances (PFAS) have attracted widespread attention in recent years due to their bioaccumulation, toxicity, and ubiquitous nature. We and others have reported that maternal exposure to PFAS is associated with adverse birth outcomes due to altered placental functions. In this study, we investigated the effects of two major PFAS compounds, perfluorobutane sulfonate (PFBS) and perfluorooctanesulfonic acid (PFOS), on the regulation of the production of angiogenic factors and stress response in placental multinucleated syncytial BeWo cells using qRT-PCR and ELISA. Using this in vitro model, we showed that 1) PFOS or PFBS treatment did not seem to interrupt BeWo cell fusion through syncytins; 2) Exposure to PFOS at 10 μM decreased a potent angiogenic factor PlGF gene expression, which is implicated in preeclampsia; 3) Exposure to either PFOS or PFBS significantly decreased the production of CGB7 and hCG except hCG secretion in PFOS (10 nM) and PFBS (100 nM) treatment groups; 4) Exposure to PFOS (10 μM) increased the gene expression of the stress response molecules CRH while neither PFOS nor PFBS treatment affected a stress mitigation factor 11β-HSD2 expression. Our results demonstrate that exposure to PFOS or PFBS impacts several key pathways involved in placental cell functions. PFOS seems more potent than PFBS. These novel findings provide a potential explanation for the adverse reproductive complications associated with prenatal exposure to PFOS or PFBS, including preeclampsia and contribute to our knowledge of the reproductive toxicity of PFAS, specifically PFOS and PFBS.

Early life exposure to per- and polyfluoroalkyl substances (PFAS) and latent health outcomes: A review including the placenta as a target tissue and possible driver of peri- and postnatal effects

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous drinking water contaminants of concern due to mounting evidence implicating adverse health outcomes associated with exposure, including reduced kidney function, metabolic syndrome, thyroid disruption, and adverse pregnancy outcomes. PFAS have been produced in the U.S. since the 1940s and now encompass a growing chemical family comprised of diverse chemical moieties, yet the toxicological effects have been studied for relatively few compounds. Critically, exposures to some PFAS in utero are associated with adverse outcomes for both mother and offspring, such as hypertensive disorders of pregnancy (HDP), including preeclampsia, and low birth weight. Given the relationship between HDP, placental dysfunction, adverse health outcomes, and increased risk for chronic diseases in adulthood, the role of both developmental and lifelong exposure to PFAS likely contributes to disease risk in complex ways. Here, evidence for the role of some PFAS in disrupted thyroid function, kidney disease, and metabolic syndrome is synthesized with an emphasis on the placenta as a critical yet understudied target of PFAS and programming agent of adult disease. Future research efforts must continue to fill the knowledge gap between placental susceptibility to environmental exposures like PFAS, subsequent perinatal health risks for both mother and child, and latent health effects in adult offspring.

Perfluorooctane sulfonic acid (PFOS) exposure during pregnancy increases blood pressure and impairs vascular relaxation mechanisms in the adult offspring

Perfluorooctanesulfonate (PFOS) is a persistent environmental agent. We examined whether PFOS exposure during pregnancy alters blood pressure in male and female offspring, and if this is related to sex-specific changes in vascular mechanisms. PFOS was administered through drinking water (50 μg/mL) to pregnant Sprague-Dawley rats from gestational day 4 until delivery. PFOS-exposure decreased maternal weight gain but did not significantly alter feed and water intake in dams. The male and female pups born to PFOS mothers were smaller in weight by 29 % and 27 %, respectively. The male PFOS offspring remained smaller through adulthood, but the female PFOS offspring exhibited catch-up growth. The blood pressure at 12 and 16 weeks of age was elevated at similar magnitude in PFOS males and females than controls. Mesenteric arterial relaxation to acetylcholine was reduced in both PFOS males and females, but the extent of decrease was greater in females. Relaxation to sodium-nitroprusside was reduced in PFOS females but unaffected in PFOS males. Vascular eNOS expression was not changed, but phospho(Ser¹¹⁷⁷)-eNOS was decreased in PFOS males. In PFOS females, both total eNOS and phospho(Ser¹¹⁷⁷)-eNOS expression were reduced. In conclusion, PFOS exposure during prenatal life (1) caused low birth weight followed by catch-up growth only in females (2) lead to hypertension of similar magnitude in both males and females; (2) decreased endothelium-dependent vascular relaxation in males but suppressed both endothelium-dependent and -independent relaxation in females. The endothelial dysfunction is associated with reduced activity of eNOS in males and decreased expression and activity of eNOS in females.

Exposure to perfluorooctanoic acid (PFOA) decreases neutrophil migration response to injury in zebrafish embryos

Objective

Perfluorooctanoic acid (PFOA) is a ubiquitous environmental contaminant and a known immune suppressant in humans and experimental animal models. Studies on PFOA have focused on suppression of the adaptive immune response; however, little is known of the impact on innate immunity, especially during embryogenesis. Therefore, we utilized the zebrafish chemotaxis assay coupled with in situ hybridization for myeloperoxidase expression to determine the effects of PFOA exposure on neutrophil migration in the developing zebrafish embryo. Zebrafish embryos are a well-established in vivo model that exhibit high homology with the development of human innate immunity.

Results

Treatment of zebrafish with increasing concentrations of PFOA identified the lethal concentration in 50% of the embryos (LC₅₀) to be 300 mg/L. Utilizing the zebrafish chemotaxis assay, this study showed that wounding induced significant neutrophil migration to the site of injury, and that neutrophil number in the wound region was significantly reduced in response to 48-h PFOA exposure (well below doses causing acute mortality). This study demonstrates that the developing embryo is sensitive to PFOA exposure and that PFOA can modify the innate immune system during embryonic development. These results lay the groundwork for future investigation on the mechanisms underlying PFOA-induced developmental immunotoxicity.