Environmental Chemicals in an Urban Population of Pregnant Women and Their Newborns from San Francisco

Association between perfluoroalkyl and polyfluoroalkyl substances and adolescents' sleep disorders: NHANES 2005-2018

Background

Previous research indicates that per- and polyfluoroalkyl substances (PFAS) can disrupt metabolism and neurological function via endocrine pathway interference and neuroinflammation. These effects may impair melatonin secretion and disrupt circadian rhythm regulation, suggesting potential links to sleep health. However, the impact of PFAS exposure on adolescent sleep remains unclear. This study examines the associations between PFAS exposure and sleep health indicators in U.S. adolescents.

Methods

Data from 838 adolescents who participated in the 2005-2018 National Health and Nutrition Examination Survey (NHANES) were analyzed to investigate the association between PFAS exposure and physician-diagnosed sleep disorders. Eight PFAS compounds were identified. Multivariate logistic regression models, restricted cubic spline (RCS) curves, Bayesian kernel machine regression (BKMR), and weighted quantile sum (WQS) regression were used to assess single, linear, and combined effects on adolescent sleep disorders.

Results

Negative associations were observed between adolescent sleep disorders and three PFAS compounds, specifically perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and perfluorononanoic acid (PFNA). RCS analysis revealed a significant linear relationship (P for non-linear > 0.05). The BKMR and WQS models demonstrated a combined effect of PFAS exposure on sleep disorders, with PFOS demonstrating the most substantial contribution (effect size: 0.91). The stratified analysis revealed that PFOS exposure had a greater impact on females [odds ratio (OR): 0.54, 95% confidence interval (CI): 0.33-0.87] than males (OR: 0.50, 95% CI: 0.24-1.01), suggesting sex-specific differences in vulnerability.

Conclusions

Our findings indicate a negative correlation between specific PFAS and specific sleep disorders in adolescents, with PFOS being the dominant effect component in the PFAS mixture and stronger effects observed in females. However, due to the cross-sectional nature of the study, a causal relationship cannot be established. These results highlight the potential public health impact of PFAS exposure and the need to further investigate the underlying mechanisms and causal pathways in future longitudinal or experimental studies.

PBScreen: A server for the high-throughput screening of placental barrier-permeable contaminants based on multifusion deep learning

Contaminants capable of crossing the placental barrier (PB) adversely affect female reproduction and fetal development. The rapid identification of PB-permeable contaminants is urgently needed due to the inefficiencies of conventional cell-based transwell assays for the screening of large quantities of chemicals. Herein, we construct a PBScreen server using a multifusion deep learning (DL) model for the accurate and rapid screening of PB-permeable chemicals. This model is trained using graph convolutional networks and deep neural networks algorithms. It achieves state-of-the-art performance with an accuracy of 0.927, a false negative rate of 0.074, and an area under the receiver operating characteristic curve of 0.960. The robustness and generalization of the model as assessed using the external validation set and BeWo cell-based transwell assays demonstrate its potential for diverse applications. Our study establishes an efficient high-throughput screening tool that aids in screening PB-permeable chemicals, thereby enhancing the risk assessment of contaminants associated with key public health concerns.

Comprehensive analysis of transplacental transfer of environmental pollutants detected in paired maternal and cord serums

Prenatal exposure to hazardous environmental pollutants is a critical global concern due to their confirmed presence in umbilical cord blood, indicating the ability of pollutants to cross the placental barrier and expose the fetus to harmful compounds. However, the transplacental transfer efficiencies (TTEs) of many pollutants remain underexplored. Herein, we developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantitatively analyze 91 environmental pollutants, including 13 bisphenols (BPs), 18 organophosphorus flame retardants (OPFRs), 7 brominated and other flame retardants (BFRs), 34 phthalates (PAEs), and 19 per- and polyfluoroalkyl substances (PFASs), in paired maternal and cord serums. 38 pollutants were detected in serums, including 5 BPs, 13 OPFRs, 2 BFRs, 4 PAEs, and 14 PFASs. Among the detected pollutants, bisphenol A (BPA) exists in the highest concentration (GM: 10.92 ng/mL in maternal serums and 12.66 ng/mL in cord serums), followed by tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), perfluorooctanoic acid (PFOA), and 4,4'-(1,3-phenylenediisopropylidene) bisphenol (BPM). The exposure concentrations of the same type of pollutants were highly correlated between maternal and cord serums. Perfluorohexanoic acid (PFHxA) had the highest TTE value (5.526), while perfluorooctane sulfonic acid (PFOS) had the lowest (0.206). TTEs of PFOS and perfluorononanoic acid (PFNA) were higher for female newborns, whereas TTEs of perfluorohexadecanoic acid (PFHxDA) and perfluorodecane sulfonic acid (PFDS) were higher for male newborns. Moreover, the expression levels of the transplacental transporters ABCA1, ABCC2, ABCC3, ABCC4, ABCG1, SLCO3A1, and SLC22A3 were associated with the transplacental transfer of triphenyl phosphate (TPHP), TDCIPP, di-n-propyl phthalate (DPRP), perfluoroundecanoic acid (PFUnDA), perfluorotridecanoic acid (PFTrDA), and PFOS. Further research is essential to unveil the mechanisms involved in the transplacental transfer of environmental pollutants, ultimately boosting our comprehension of their impact on fetal health and birth outcomes.

Per- and polyfluoroalkyl substances in paired serum and breastmilk samples among pregnant farmworkers in Thailand

Per- and polyfluoroalkyl substances (PFAS) are widely detected in pregnant persons and can be transferred to the developing fetus in utero. Breastfeeding may represent an important source of PFAS exposure for infants. However, studies quantifying levels of PFAS in breastmilk samples remain scarce, particularly in low- and middle-income countries. We examined breastmilk as a postnatal PFAS exposure source among mother-infant pairs in Thailand. Pregnant farmworkers were enrolled in the Study of Asian Women and their Offspring's Development and Environmental Exposures (SAWASDEE), a prospective birth cohort in Northern Thailand, between 2017 and 2019. We quantified levels of eight PFAS in maternal serum samples obtained during the second trimester, as well as in breastmilk samples obtained at 9.5 months and 11.5 months in infancy (N = 46 matched pairs). For each PFAS, we calculated lactational (serum to milk) transfer efficiencies and lactational estimated daily intake. PFOA, PFOS PFHxS, PFNA, PFDA, and PFUnDA were detected in >90% of serum samples. PFOS was detected in >60% of breastmilk samples obtained at 9.5 and 11.5 months, while PFNA was detected in >50% of 9.5-month breastmilk samples only. All remaining PFAS were detected in <50% of breastmilk samples. The lactational transfer efficiency for PFOS was 7.03% (SD = 5.78) and 5.83% (SD = 5.21) at 9.5 and 11.5 months, respectively. The lactational estimated daily intake for PFOS was 12.1 ng/kg bodyweight/day (SD = 5.49) and 10 ng/kg bodyweight/day (SD = 6.22) at 9.5 and 11.5 months, respectively. For PFNA, the lactational transfer efficiency and estimated daily intake at 9.5 months was 14.7% (SD = 14.3) and 6.14% (SD = 3.40), respectively. Within one of the first PFAS biomonitoring studies conducted in Thailand, we found that legacy PFAS were widely detected in serum, and some compounds were also detected in breastmilk of farmworkers. This study provides new evidence enhancing our understanding of postnatal exposure to PFAS.

Participant perspectives related to individual chemical exposure report-back approaches in three environmental health studies

Returning results to participants of environmental exposure studies has become more common in recent years. Despite evidence of benefits for study participants, there are challenges in communicating results to people with limited resources or capacity to mitigate chemical exposures. We interviewed N = 54 participants and compared exposure report-back conducted in 2010-2013 across three susceptible study populations: 1) low-income pregnant individuals in the Chemicals in Our Bodies (CIOB) study; 2) the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort; and 3) early childhood educators (ECE). Report-back differed between the cross-sectional studies (CIOB and ECE), which offered an opportunity to consult with research staff by phone or email, and the prospective cohort study (CHAMACOS), which allowed for participants to discuss individual and group-level results directly with researchers at a community meeting. Participants in all three studies were motivated to participate by children's health and wanted more information about health implications and exposure reduction strategies, with cost and limited resources cited as common barriers to change. We observed overall positive experiences with report-back across studies, with improved environmental health literacy and constructive learning experiences that were most evident in CHAMACOS. While many noted individual actions they had made or intended to make to reduce exposures, CHAMACOS participants were more likely to mention systems-level changes achieved through actions such as contacting decision-makers and raising community awareness. Our findings suggest that researchers may have a unique opportunity to support environmental health literacy and informed action at both the individual and community or policy levels through long-term study engagement, various forms of direct consultation with study participants, and thoughtful report-back methods that leverage existing tools and are sensitive to barriers faced by specific study populations. This work informs best practices for communicating chemical exposure results among sensitive or highly exposed communities.

Lead exposure at the feto-maternal interface: a cause for concern for fetal membrane trophoblasts

The integrity of fetal membranes enables biological functions that protect the fetus and maintain the pregnancy. Any compromise in fetal membrane function can predispose a pregnant woman to prelabor rupture of the membranes (pPROMs) and subsequently to preterm birth (PTB). Epidemiologic data suggest that lead exposure during pregnancy is one of several risk factors associated with PTB and pPROM. This heavy metal can cross placental and fetal membrane barriers, disrupting homeostasis in these tissues. Autophagy contributes to the maintenance of fetal membrane homeostasis during gestation, and dysfunctional autophagy is associated with pPROM. In this study, we determined the mechanistic impact of lead-induced cellular changes, autophagy, senescence, and inflammation in chorion trophoblast cells (CTCs) and amnion epithelial cells (AECs) of the fetal membranes. Lead exposure in CTCs induced autophagy dysfunction (increase in LC3B-II), augmented senescence (increased SA-β-galactosidase activity), and increased the release of inflammation. In AECs, lead exposure did effect autophagy, senescence, nor inflammation. The differential changes observed in CTCs and AECs after exposure to high lead concentrations may promote the weakening of fetal membranes and contribute to preterm rupture.

Gestational exposure to environmental chemical mixtures and cognitive abilities in children: A pooled analysis of two North American birth cohorts

BACKGROUND

Gestational exposures to single toxic chemicals have been associated with cognitive deficits in children, but few studies have explored chemical mixtures.

OBJECTIVES

To evaluate the associations between gestational chemical biomarker mixtures and cognitive abilities in children from two prospective cohorts.

METHODS

This study includes 617 birthing parent-child pairs from the Health Outcomes and Measures of the Environment (HOME) and Maternal-Infant Research on Environmental Chemicals (MIREC) Studies. We measured 29 chemical biomarkers (metals, persistent organic pollutants, perfluoroalkyl substances, organophosphate esters, phenols, phthalates, organophosphate pesticides, and parabens) in pregnant individuals during early pregnancy and their children's cognitive abilities at ages 3 to 5 years using Wechsler Intelligence Scales. We assessed linear associations using quantile g-computation and non-linear associations using Bayesian Kernel Machine Regression (BKMR) methods, adjusted for covariates.

RESULTS

Using quantile g-computation, we observed overall null associations between the chemical biomarker mixture and cognitive outcomes among preschool-age children. Although statistical significance was not attained for child sex as an effect modifier, our stratified analysis unveiled a moderate divergence in association trends. We noted a marginal inverse trend between the chemical biomarker mixture and cognitive scores [Full-Scale Intelligence Quotient (FSIQ) & Performance Intelligence Quotient (PIQ)] among males. Using quantile g-computation and BKMR methods, we observed that PBDE47, PFHxS, and di-ethyl organophosphates commonly contributed towards a decline in FSIQ scores in males. Among males, a quartile increase in the chemical biomarker mixture was associated with a 0.64-point decrease (95% CI: -2.59, 1.31) in the FSIQ score and a 1.59-point decrease (95% CI: -3.72, 0.54) in the PIQ score.

CONCLUSION

In this study, we observed a weak negative trend between the gestational chemical biomarker mixture and cognitive scores (FSIQ/PIQ) among males. Further studies are needed to confirm the findings between the longitudinal chemical biomarkers and child cognitive scores at school ages.

Associations of prenatal urinary melamine, melamine analogues, and aromatic amines with gestational duration and fetal growth in the ECHO Cohort

Melamine, its analogues, and aromatic amines (AAs) were commonly detected in a previous study of pregnant women in the Environmental influences on Child Health Outcomes (ECHO) Cohort. While these chemicals have identified toxicities, little is known about their influences on fetal development. We measured these chemicals in gestational urine samples in 3 ECHO cohort sites to assess associations with birth outcomes (n = 1,231). We estimated beta coefficients and 95% confidence intervals (CIs) using adjusted linear mixed models with continuous dilution-standardized concentrations (log2 transformed and scaled by interquartile range, IQR) or binary indicators for detection. As secondary analyses, we repeated analyses using categorical outcomes. Forty-one of 45 analytes were detected in at least one sample, with > 95 % detection of melamine, cyanuric acid, ammelide, and aniline. Higher melamine concentration was associated with longer gestational age (β^ per IQR increase of log2-transformed: 0.082 [95 % CI: -0.012, 0.177]; 2nd vs 1st tertile: 0.173 [-0.048, 0.394]; 3rd vs 1st tertile: 0.186 [-0.035, 0.407]). Similarly in secondary analyses using categorical outcomes, an IQR increase in log2(melamine) was associated with 1.22 [0.99, 1.50] higher odds of post-term (>40 & ≤42 weeks) as compared to full-term (≥38 & ≤40 weeks). Several AAs were associated with birthweight and gestational length, with the direction of associations varying by AA. Some stronger associations were observed in females. Our findings suggest melamine and its analogs and AAs may influence gestational length and birthweight.

[Research advances in the transplacental transfer efficiencies of environmental pollutants]

Industrialization has led to significant increases in the types and quantities of pollutants, with environmental pollutants widely present in various media, including the air, food, and everyday items. These pollutants can enter the human body via multiple pathways, including ingestion through food and absorption through the skin; this intrusion can disrupt the production, release, and circulation of hormones in the body, resulting in a range of illnesses that affect the reproductive, endocrine, and nervous systems. Consequently, these pollutants pose substantial risks to human health. In particular, fetuses are highly sensitive to environmental pollutants during critical stages of development, and exposure during periods of growth and development can result in more-obvious and severe health hazards that can lead to preterm birth, low birth weight, and fetal malformations. The placenta acts as a barrier between the mother and fetus, and selectively filters certain pollutants. While some pollutants remain in the maternal bloodstream, others cross the placental barrier into the fetal umbilical blood through passive diffusion, placental transport proteins, or endocytosis. The transplacental transfer efficiency (TTE) is the ratio of the level of the pollutant in the umbilical blood to that in the maternal blood, and is a valuable metric for evaluating the ability of a pollutant to breach the placental barrier. A higher TTE implies that a larger proportion of pollutants are transferred from the mother to the fetus, thereby amplifying the potential risks to the fetus. Mass spectrometry-based detection methods are extensively used in the chemical and environmental sciences because they are exceptionally sensitive and highly resolving. This analytical technique involves ionizing compounds within a sample and identifying them based on their distinct mass-to-charge ratios; it enables both qualitative and quantitative analyses of various environmental pollutants. Current methodologies for examining the TTE of a pollutant include in-vitro experiments, animal studies, epidemiologic studies, and model calculation; these approaches help to evaluate the transfer of pollutants from mother to fetus via the placenta. Analyzing the TTEs of different chemicals enables high-risk pollutants to be identified and provides an understanding of their abilities to cross the placenta. Research on the transplacental transfer of environmental pollutants has focused mainly on per- and polyfluoroalkyl substances (PFASs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs), with relatively few studies on the TTEs of other pollutants reported. Pollutant transfer through the placenta is a complex process that is influenced by factors that include the physical and chemical properties of the pollutant (e.g., molecular mass, solubility, and lipophilicity), maternal factors (e.g., maternal health and lifestyle, maternal genetics, environmental conditions, and socioeconomic status), and placental characteristics (e.g., placental maturity, placental blood flow, transport proteins, and metabolic enzymes). This review summarizes recent advances in research on the TTEs of environmental pollutants, focusing on analytical methods, the TTEs of PFASs, PBDEs, PCBs, and OCPs, and the pivotal factors that influence TTEs. Studying the TTEs of pollutants enables their characteristics to be elucidated, thereby providing support data for research on the exposure, transfer, and accumulation of pollutants in the human body, as well as a theoretical framework for understanding the mechanism of transplacental transfer of environmental pollutants. This research is expected to play a vital role in assessing the impact of environmental pollutants on the health of pregnant women and their fetuses.

Per- and polyfluoroalkyl substances (PFAS): Trends in mass spectrometric analysis for human biomonitoring and exposure patterns from recent global cohort studies

Per- and polyfluoroalkyl substances (PFAS) are widespread environmental contaminants that have been shown to contribute to human exposure, thereby raising a range of health concerns. In this context, human biomonitoring is essential for linking exposure levels of PFAS with their potential health risks. Mass spectrometry-based analytical techniques have been extensively adopted for the evaluation of PFAS levels across various cohorts. However, challenges arising from the use of biological samples (e.g., plasma, serum, urine, etc.) necessitate ongoing research and refinement of analytical methodologies. This review provides an overview of current trends in mass spectrometry-based approaches for human biomonitoring of PFAS, including sample collection and preparation, and instrumental techniques. We also explore analytical strategies to overcome challenges in obtaining PFAS-free blank matrices and address the risk of background contamination. Moreover, this review examines differing PFAS exposure patterns across regions by analyzing recent international cohort studies, specifically those conducted in the US and China over the past five years. Accordingly, several key research gaps in biomonitoring studies that need to be addressed moving forward are highlighted.

A Prospective Analysis of Per- and Polyfluoroalkyl Substances from Early Pregnancy to Delivery in the Atlanta African American Maternal-Child Cohort

BACKGROUND

Longitudinal trends in per- and polyfluoroalkyl substances (PFAS) serum concentrations across pregnancy have not been thoroughly examined, despite evidence linking prenatal PFAS exposures with adverse birth outcomes.

OBJECTIVES

We sought to characterize longitudinal PFAS concentrations across pregnancy and to examine the maternal-fetal transfer ratio among participants in a study of risk and protective factors for adverse birth outcomes among African Americans.

METHODS

In the Atlanta African American Maternal-Child cohort (2014-2020), we quantified serum concentrations of four PFAS in 376 participants and an additional eight PFAS in a subset of 301 participants during early (8-14 weeks gestation) and late pregnancy (24-30 weeks gestation). Among these, PFAS concentrations were also measured among 199 newborns with available dried blood spot (DBS) samples. We characterized the patterns, variability, and associations in PFAS concentrations at different time points across pregnancy using intraclass correlation coefficients (ICCs), maternal-newborn pairs transfer ratios, linear mixed effect models, and multivariable linear regression, adjusting for socioeconomic and prenatal predictors.

RESULTS

Perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) were detected in > 95 % of maternal samples, with PFHxS and PFOS having the highest median concentrations. We observed high variability in PFAS concentrations across pregnancy time points (ICC = 0.03 - 0.59 ). All median PFAS concentrations increased from early to late pregnancy, except for PFOA and N-methyl perfluorooctane sulfonamido acetic acid (NMFOSAA), which decreased [paired t -test for all PFAS p < 0.05 except for PFOA and perfluorobutane sulfonic acid (PFBS)]. Prenatal serum PFAS were weakly to moderately correlated with newborn DBS PFAS (- 0.05 < rho < 0.49 ). The median maternal-fetal PFAS transfer ratio was lower for PFAS with longer carbon chains. After adjusting for socioeconomic and prenatal predictors, in linear mixed effect models, the adjusted mean PFAS concentrations significantly increased during pregnancy, except for PFOA. In multivariable linear regression, PFAS concentrations in early pregnancy significantly predicted the PFAS concentrations in late pregnancy and in newborns.

DISCUSSION

We found that the concentrations of most PFAS increased during pregnancy, and the magnitude of variability differed by individual PFAS. Future studies are needed to understand the influence of within-person PFAS variability during and after pregnancy on birth outcomes. https://doi.org/10.1289/EHP14334.

Environmental Health Attitudes, Practices, and Educational Preferences: A National Survey of Reproductive-Aged Women in Canada

Prenatal exposures to environmental toxicants can adversely affect fetal and child development and lead to increased risk of chronic disease. While regulatory action is essential to reduce sources of environmental toxicants, prenatal care presents an opportunity to educate, mobilize, and support prospective parents to reduce exposures to such hazards. As the first phase of an interdisciplinary research collaboration to inform the development of prenatal environmental health education strategy in Canada, we surveyed reproductive-aged female individuals. The online survey (July-September 2021) yielded a nationally representative sample of 1914 reproductive-aged females living in Canada. The questionnaire topics addressed the respondents' knowledge and perceptions of environmental health risks, preventive actions and related facilitators and barriers, information sources and preferences, reproductive history, and demographics. The analysis included bivariate and multivariate techniques. Our results suggest broad awareness among reproductive-aged females that exposure to toxicants can be harmful, and that reducing prenatal exposures can benefit child health. However, fewer than half of respondents felt that they had enough knowledge to take protective measures. Despite high levels of preference for prenatal care as an ideal context for learning about environmental health risks and protective measures, fewer than one in four respondents had ever discussed environmental health concerns with a healthcare provider. Our findings reveal a knowledge-action gap and a corresponding opportunity to improve environmental health education and advocacy in prenatal care in the Canadian context.

Prenatal exposure to persistent and non-persistent chemical mixtures and associations with adverse birth outcomes in the Atlanta African American Maternal-Child Cohort

BACKGROUND

African Americans (AAs) experience higher rates of preterm birth and fetal growth restriction relative to other pregnant populations. Differential in utero exposure to environmental chemicals may partially explain these health disparities, as AAs are disproportionately exposed to environmental hazards.

OBJECTIVE

We examined the individual and mixture effects of non-persistent chemicals and persistent organic pollutants (POPs) on gestational age at birth and birthweight for gestational age z-scores within a prospective cohort of pregnant AAs.

METHODS

First-trimester serum and urine samples obtained from participants within the Atlanta African American Maternal-Child cohort were analyzed for 43 environmental chemicals, including per-and polyfluoroalkyl substances (PFAS), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides, pyrethroid insecticides, phthalates, bisphenol A, nicotine, and the primary metabolite of delta-9-tetrahydrocannabinol. Linear regression was used to estimate individual associations between chemicals and gestational age and birthweight z-scores (N ranging from 107 to 523). Mixture associations were estimated using quantile g-computation, principal component (PC) analyses, and hierarchical Bayesian kernel machine regression among complete cases (N = 86).

RESULTS

Using quantile g-computation, increasing all chemical exposures by one quantile was modestly associated with a reduction in gestational age (mean change per quartile increase = -0.47, 95% CI = -1.56, 0.61) and birthweight z-scores (mean change per quartile increase = -0.49, 95% CI = -1.14, 0.15). All PCs were associated with a reduction in birthweight z-scores; associations were greatest in magnitude for the two PCs reflecting exposure to combined tobacco, insecticides, PBDEs, and phthalates. In single pollutant models, we observed inconsistent and largely non-significant associations.

SIGNIFANCE

We conducted multiple targeted exposure assessment methods to quantify levels of environmental chemicals and leveraged mixture methods to quantify their joint effects on gestational age and birthweight z-scores. Our findings suggest that prenatal exposure to multiple classes of persistent and non-persistent chemicals is associated with reduced gestational age and birthweight z-scores in AAs.

IMPACT

African Americans (AAs) experience higher rates of preterm birth and fetal growth restriction relative to other pregnant populations. Differential in utero exposure to environmental chemicals may partially explain these health disparities, as AAs are disproportionately exposed to environmental hazards. In the present study, we analyzed serum and urine samples for levels of 43 environmental chemicals. We used quantile g-computation, principal component analysis, and BKMR to assess associations between chemical exposure mixtures and adverse birth outcomes. Our findings suggest that prenatal exposure to multiple classes of chemicals is associated with reduced birthweight z-scores, a proxy for fetal growth, in AAs.

Associations of per- and polyfluoroalkyl substances with maternal early second trimester sex-steroid hormones

BACKGROUND/AIMS

Pregnant women are exposed to persistent environmental contaminants, including per- and polyfluoroalkyl substances (PFAS) that disrupt thyroid function. However, it is unclear if PFAS alter maternal sex-steroid hormone levels, which support pregnancy health and fetal development.

METHODS

In Illinois women with relatively high socioeconomic status (n = 460), we quantified perfluorononanoic (PFNA), perfluorooctane sulfonic (PFOS), perfluorooctanoic (PFOA), methyl-perfluorooctane sulfonamide acetic acid, perfluorohexanesulphonic (PFHxS), perfluorodecanoic (PFDeA), and perfluoroundecanoic (PFUdA) acid concentrations in fasting serum samples at median 17 weeks gestation, along with plasma progesterone, testosterone, and estradiol. We evaluated covariate-adjusted associations of ln-transformed hormones with each ln-transformed PFAS individually using linear regression and with the PFAS mixture using quantile-based g-computation (QGComp).

RESULTS

Interquartile range (IQR) increases in PFOS were associated with higher progesterone (%Δ 3.0; 95%CI: -0.6, 6.6) and estradiol (%Δ: 8.1; 95%CI: 2.2, 14.4) levels. Additionally, PFHxS was positively associated with testosterone (%Δ: 10.2; 95%CI: 4.0, 16.7), whereas both PFDeA and PFUdA were inversely associated with testosterone (%Δ: -5.7; 95%CI: -10.3, -0.8, and %Δ: -4.1; 95%CI: -7.6, -0.4, respectively). The IQR-standardized PFAS mixture was not associated with progesterone (%Δ: 1.6; 95%CI: -5.8, 9.2), due equal partial positive (%Δ: 9.2; driven by PFOA) and negative (%Δ: -7.4; driven by PFOS) mixture associations. Similarly, the mixture was not associated with testosterone (%Δ: 5.3; 95%CI: -9.0, 20.1), due to similar partial positive (%Δ: 23.6; driven by PFHxS) and negative (%Δ: -17.4; driven by PFDeA) mixture associations. However, we observed a slightly stronger partial positive (%Δ: 25.6; driven by PFOS and PFUdA) than negative (%Δ: -16.3; driven by PFOA) association resulting in an overall non-significant positive trend between the mixture and estradiol (%Δ: 8.5; 95%CI: -3.7, 20.9).

CONCLUSION

PFAS mixture modeled using QGComp was not associated with maternal sex-steroid hormones due to potential opposing effects of certain PFAS. Additional prospective studies could corroborate these findings.

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.

Cross-Sectional Associations between Prenatal Per- and Poly-Fluoroalkyl Substances and Bioactive Lipids in Three Environmental Influences on Child Health Outcomes (ECHO) Cohorts

Prenatal per- and poly-fluoroalkyl substances (PFAS) exposure may influence gestational outcomes through bioactive lipids─metabolic and inflammation pathway indicators. We estimated associations between prenatal PFAS exposure and bioactive lipids, measuring 12 serum PFAS and 50 plasma bioactive lipids in 414 pregnant women (median 17.4 weeks' gestation) from three Environmental influences on Child Health Outcomes Program cohorts. Pairwise association estimates across cohorts were obtained through linear mixed models and meta-analysis, adjusting the former for false discovery rates. Associations between the PFAS mixture and bioactive lipids were estimated using quantile g-computation. Pairwise analyses revealed bioactive lipid levels associated with PFDeA, PFNA, PFOA, and PFUdA (p < 0.05) across three enzymatic pathways (cyclooxygenase, cytochrome p450, lipoxygenase) in at least one combined cohort analysis, and PFOA and PFUdA (q < 0.2) in one linear mixed model. The strongest signature revealed doubling in PFOA corresponding with PGD2 (cyclooxygenase pathway; +24.3%, 95% CI: 7.3-43.9%) in the combined cohort. Mixture analysis revealed nine positive associations across all pathways with the PFAS mixture, the strongest signature indicating a quartile increase in the PFAS mixture associated with PGD2 (+34%, 95% CI: 8-66%), primarily driven by PFOS. Bioactive lipids emerged as prenatal PFAS exposure biomarkers, deepening insights into PFAS' influence on pregnancy outcomes.

Association of placental weight at birth with maternal whole blood concentration of heavy metals (cadmium, lead, mercury, selenium, and manganese): The Japan Environment and Children's Study (JECS)

BACKGROUND

Lifelong health is dependent on prenatal growth and development, influenced by the placental intrauterine environment. Charged with dual functions--exchange of oxygen and nutrients as well as a barrier against toxins--the placenta itself is susceptible to environmental exposure to heavy metals.

OBJECTIVE

To examine the use of placenta weight as a biomarker for heavy metal exposure using a large Japanese cohort of pregnant women.

METHODS

The placenta weight, as a biomarker of exposure to heavy metals (cadmium, lead, and mercury), was investigated using data from the Japan Environment and Children's Study (2011-2014). Selenium and manganese were included as factors directly affecting fetal growth or heavy metal toxicity. Maternal blood samples collected in the second or third trimester were used to measure heavy metal concentrations. The association between maternal blood metal concentrations and placenta weight was explored by applying Z scores and multivariable logistic regression analysis and classifying participants into quartiles (Q1, Q2, Q3, and Q4) according to metal concentrations.

RESULTS

This study included a total of 73,005 singleton pregnant women who delivered via live births and met the inclusion criteria. The median heavy metal concentrations in the maternal whole blood were 0.662 ng/g cadmium, 5.85 ng/g lead, 3.61 ng/g mercury, 168 ng/g selenium, and 15.3 ng/g manganese. Regression analysis revealed a significant correlation between placenta weight Z scores and maternal blood metal concentrations: cadmium, 0.0660 (standard error = 0.0074, p < 0.001); selenium, -0.3137 (standard error = 0.0276, p < 0.001); and manganese, 0.1483 (standard error = 0.0110, p < 0.001).

CONCLUSION

This study provides a robust examination of the association between heavy metal exposure and placenta weight. Cadmium and manganese showed a positive correlation with significant differences, whereas selenium showed a negative correlation. Essential elements notably affect placenta weight differently. No significant association was noted between lead or mercury and placenta weight.

Association between maternal heavy metal exposure and Kawasaki Disease, the Japan Environment and Children's Study (JECS)

Kawasaki disease (KD) is an acute systemic vasculitis primarily affecting young children, with an unclear etiology. We investigated the link between maternal heavy metal exposure and KD incidence in children using the Japan Environment and Children's Study, a large-scale nationwide prospective cohort with approximately 100,000 mother-child pairs. Maternal blood samples collected during the second/third trimester were analyzed for heavy metals [mercury (Hg), cadmium (Cd), lead (Pb), selenium (Se), manganese (Mn)], divided into four quartiles based on concentration levels. KD incidence within the first year of life was tracked via questionnaire. Among 85,378 mother-child pairs, 316 children (0.37%) under one year were diagnosed with KD. Compared with the lowest concentration group (Q1), the highest (Q4) showed odds ratios (95% confidence interval) for Hg, 1.29 (0.82-2.03); Cd, 0.99 (0.63-1.58); Pb, 0.84 (0.52-1.34); Se, 1.17 (0.70-1.94); Mn, 0.70 (0.44-1.11), indicating no concentration-dependent increase. Sensitivity analyses with logarithmic transformation and extended outcomes up to age 3 yielded similar results. No significant association was found between maternal heavy metal levels and KD incidence, suggesting that heavy metal exposure does not increase KD risk.

Associations of per- and polyfluoroalkyl substances (PFAS) and their mixture with risk of rheumatoid arthritis in the U.S. adult population

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are known environmental contaminants with immunosuppressive properties. Their connection to rheumatoid arthritis (RA), a condition influenced by the immune system, is not well studied. This research explores the association between PFAS exposure and RA prevalence.

METHODS

This research utilized data from the NHANES, encompassing a sample of 10,496 adults from the 2003-2018 cycles, focusing on serum levels of several PFAS. The presence of RA was determined based on self-reports. This study used multivariable logistic regression to assess the relationship between individual PFAS and RA risk, adjusting for covariates to calculate odds ratios (ORs). The combined effects of PFAS mixtures were evaluated using BKMR, WQS regression, and quantile g-computation. Additionally, sex-specific associations were explored through stratified analysis.

RESULTS

Higher serum PFOA (OR = 0.88, 95% CI: 0.79, 0.98), PFHxS (OR = 0.91, 95% CI: 0.83, 1.00), PFNA (OR = 0.87, 95% CI: 0.77, 0.98), and PFDA (OR = 0.89, 95% CI: 0.81, 0.99) concentration was related to lower odds of RA. Sex-specific analysis in single chemical models indicated the significant inverse associations were only evident in females. BKMR did not show an obvious pattern of RA estimates across PFAS mixture. The outcomes of sex-stratified quantile g-computation demonstrated that an increase in PFAS mixture was associated with a decreased odds of RA in females (OR: 0.76, 95% CI: 0.62, 0.92). We identified a significant interaction term of the WQS*sex in the 100 repeated hold out WQS analysis. Notably, a higher concentration of the PFAS mixture was significantly associated with reduced odds of RA in females (mean OR = 0.93, 95% CI: 0.88, 0.98).

CONCLUSIONS

This study indicates potential sex-specific associations of exposure to various individual PFAS and their mixtures with RA. Notably, the observed inverse relationships were statistically significant in females but not in males. These findings contribute to the growing body of evidence indicating that PFAS may have immunosuppressive effects.

Polybrominated diphenyl ether (PBDE) exposure and adverse maternal and infant health outcomes: Systematic review

Polybrominated diphenyl ethers (PBDEs) are flame retardants found in ambient environment and are measured in humans. There are reports on general PBDE toxicity, including endocrine disrupting properties. Studies on adverse maternal and infant outcomes and underlying toxicity mechanisms needs to be understood. The objective of this study was to conduct a systematic review to examine the state of science on the relationship between PBDE and adverse maternal/infant health outcomes and related maternal biomarker changes. This literature review was conducted using PubMed, Scopus, Embase and Web of Science for published articles from January 2005-February 2022. Article quality was assessed using Newcastle-Ottawa Scale. Of the 1518 articles, only 54 human observational studies were screened in for this review. A second reviewer examined the validity of these articles. Reports on associations between PBDE and maternal health outcomes included gestational hypertension/preeclampsia (N = 2) and gestational diabetes mellitus/glycemic index (N = 6). Meanwhile, reports on PBDE and infant outcomes (N=32) included effects on infant birth weight, birth length and cephalic perimeter, preterm birth, fetal growth restriction and APGAR scores. Although findings on PBDE exposure and adverse infant outcomes showed inconsistencies across studies, in general, negative correlations between maternal PBDEs and infant birth weight, birth length and cephalic perimeter were seen, in few cases, after stratification by sex. Association between maternal PBDE and maternal biomarkers (N=18) suggested negative impact of PBDE exposure on markers relevant to neuro-endocrine system and inflammatory processes. The review findings identified potential associations between maternal PBDE and adverse maternal/infant health outcomes. Furthermore, PBDE-related biomarker changes suggest disturbances in maternal mechanisms relevant to endocrine disrupting properties of PBDEs. The observed study heterogeneity can be attributed to factors namely, sample size, study design and statistical analysis. Overall review findings imply the necessity for further research to validate PBDE exposure-related adverse maternal/infant health effects and to validate underlying toxicity mechanisms.

Review on new approach methods to gain insight into the feto-maternal interface physiology

Non-human animals represent a large and important feature in the history of biomedical research. The validity of their use, in terms of reproducible outcomes and translational confidence to the human situation, as well as ethical concerns surrounding that use, have been and remain controversial topics. Over the last 10 years, the communities developing microphysiological systems (MPS) have produced new approach method (NAMs) such as organoids and organs-on-a-chip. These alternative methodologies have shown indications of greater reliability and translatability than animal use in some areas, represent more humane substitutions for animals in these settings, and - with continued scientific effort - may change the conduct of basic research, clinical studies, safety testing, and drug development. Here, we present an introduction to these more human-relevant methodologies and suggest how a suite of pregnancy associated feto-maternal interface system-oriented NAMs may be integrated as reliable partial-/full animal replacements for investigators, significantly aid animal-/environmental welfare, and improve healthcare outcomes.

Cross-sectional associations between prenatal maternal per- and poly-fluoroalkyl substances and bioactive lipids in three Environmental influences on Child Health Outcomes (ECHO) cohorts

Background

Per- and poly-fluoroalkyl substances (PFAS) exposure can occur through ingestion of contaminated food and water, and inhalation of indoor air contaminated with these chemicals from consumer and industrial products. Prenatal PFAS exposures may confer risk for pregnancy-related outcomes such as hypertensive and metabolic disorders, preterm birth, and impaired fetal development through intermediate metabolic and inflammation pathways.

Objective

Estimate associations between maternal pregnancy PFAS exposure (individually and as a mixture) and bioactive lipids.

Methods

Our study included pregnant women in the Environmental influences on Child Health Outcomes Program: Chemicals in our Bodies cohort (CiOB, n=73), Illinois Kids Developmental Study (IKIDS, n=287), and the ECHO-PROTECT cohort (n=54). We measured twelve PFAS in serum and 50 plasma bioactive lipids (parent fatty acids and eicosanoids derived from cytochrome p450, lipoxygenase, and cyclooxygenase) during pregnancy (median 17 gestational weeks). Pairwise associations across cohorts were estimated using linear mixed models and meta-analysis. Associations between the PFAS mixture and individual bioactive lipids were estimated using quantile g-computation.

Results

PFDeA, PFOA, and PFUdA were associated (p<0.05) with changes in bioactive lipid levels in all three enzymatic pathways (cyclooxygenase [n=6 signatures]; cytochrome p450 [n=5 signatures]; lipoxygenase [n=7 signatures]) in at least one combined cohort analysis. The strongest signature indicated that a doubling in PFOA corresponded with a 24.3% increase (95% CI [7.3%, 43.9%]) in PGD2 (cyclooxygenase pathway) in the combined cohort. In the mixtures analysis, we observed nine positive signals across all pathways associated with the PFAS mixture. The strongest signature indicated that a quartile increase in the PFAS mixture was associated with a 34% increase in PGD2 (95% CI [8%, 66%]), with PFOS contributing most to the increase.

Conclusions

Bioactive lipids were revealed as biomarkers of PFAS exposure and could provide mechanistic insights into PFAS' influence on pregnancy outcomes, informing more precise risk estimation and prevention strategies.

A Critical Review on the Opportunity to Use Placenta and Innovative Biomonitoring Methods to Characterize the Prenatal Chemical Exposome

Adverse effects associated with chemical exposures during pregnancy include several developmental and reproductive disorders. However, considering the tens of thousands of chemicals present on the market, the effects of chemical mixtures on the developing fetus is still likely underestimated. In this critical review, we discuss the potential to apply innovative biomonitoring methods using high-resolution mass spectrometry (HRMS) on placenta to improve the monitoring of chemical exposure during pregnancy. The physiology of the placenta and its relevance as a matrix for monitoring chemical exposures and their effects on fetal health is first outlined. We then identify several key parameters that require further investigations before placenta can be used for large-scale monitoring in a robust manner. Most critical is the need for standardization of placental sampling. Placenta is a highly heterogeneous organ, and knowledge of the intraplacenta variability of chemical composition is required to ensure unbiased and robust interindividual comparisons. Other important variables include the time of collection, the sex of the fetus, and mode of delivery. Finally, we discuss the first applications of HRMS methods on the placenta to decipher the chemical exposome and describe how the use of placenta can complement biofluids collected on the mother or the fetus.

Nutrition paves the way to environmental toxicants and influences fetal development during pregnancy

Nutrition plays a major role in the healthy pregnancy and development of the fetus. In addition, nutrition can expose humans to a wide range of potentially hazardous environmental constituents, such as organic pollutants and heavy metals from marine or agricultural food products while processing, producing, and packaging. Humans constantly face these constituents through air, water, soil, food, and domestic products. During pregnancy, the rate of cellular division and differentiation is higher; exposure to any of these environmental toxicants can lead to developmental defects as they cross the placental barrier and, in some cases, can harm the successive generation too, as some contaminants can act on the reproductive cells of the fetus (Diethylstilbestrol). Pregnant women are considered a vulnerable population to food contaminant exposure and require a proper dietary chart and conscious food choices. Food is a source of both essential nutrients and environmental toxicants. Here, we have researched the possible toxicants of the food industry and their influence on the fetus's in-utero development, along with the importance of dietary interventions and the need to balance a healthy diet to overcome the harms. The cumulative exposure to environmental toxicants can influence the mother's prenatal environment and affect the fetus's development.

Associations of prenatal exposure to per- and polyfluoroalkyl substances (PFAS) with measures of cognition in 7.5-month-old infants: An exploratory study

BACKGROUND

Prenatal exposure to per- and polyfluoroalkyl substances (PFAS) has been linked to a wide array of adverse maternal and child health outcomes. However, studies examining PFAS in relation to offspring cognition have been inconclusive.

OBJECTIVE

We examined whether prenatal exposure to a mixture of PFAS was related to cognition in 7.5-month-old infants.

METHODS

Our analytic sample included participants enrolled in the Chemicals in Our Bodies (CIOB) and Illinois Kids Development Study (IKIDS) cohorts (N = 163). Seven PFAS were measured in 2nd trimester maternal serum samples and were detected in >65% of participants. Infant cognition was measured with a visual recognition memory task using an infrared eye tracker when infants were 7.5 months old. This task included familiarization trials where each infant was shown two identical faces and test trials where each infant was shown the familiar face paired with a novel face. In familiarization, we assessed average run duration (time looking at familiarization stimuli before looking away) as a measure of information processing speed, in addition to time to familiarization (time to reach 20 s of looking at stimuli) and shift rate (the number of times infants looked between stimuli), both as measures of attention. In test trials, we assessed novelty preference (proportion of time looking to the novel face) to measure recognition memory. Linear regression was used to estimate associations of individual PFAS with cognitive outcomes, while Bayesian kernel machine regression (BKMR) was used to estimate mixture effects.

RESULTS

In adjusted single-PFAS linear regression models, an interquartile range increase in PFNA, PFOA, PFOS, PFHxS, PFDeA, and PFUdA was associated with an increase in shift rate, reflecting better visual attention. Using BKMR, increasing quartiles of the PFAS mixture was similarly associated with a modest increase in shift rate. There were no significant associations between PFAS exposure and time to reach familiarization (another measure of attention), average run duration (information processing speed), or novelty preference (visual recognition memory).

CONCLUSION

In our study population, prenatal PFAS exposure was modestly associated with an increase in shift rate and was not strongly associated with any adverse cognitive outcomes in 7.5-month-old infants.

A Review on Per- and Polyfluoroalkyl Substances in Pregnant Women: Maternal Exposure, Placental Transfer, and Relevant Model Simulation

Per- and polyfluoroalkyl substances (PFASs) are important and ubiquitous environmental contaminants worldwide. These novel contaminants can enter human bodies via various pathways, subsequently posing risks to the ecosystem and human health. The exposure of pregnant women to PFASs might pose risks to the health of mothers and the growth and development of fetuses. However, little information is available about the placental transfer of PFASs from mothers to fetuses and the related mechanisms through model simulation. In the present study, based upon a review of previously published literature, we initially summarized the exposure pathways of PFASs in pregnant women, factors affecting the efficiency of placental transfer, and mechanisms associated with placental transfer; outlined simulation analysis approaches using molecular docking and machine learning to reveal the mechanisms of placental transfer; and finally highlighted future research emphases that need to be focused on. Consequently, it was notable that the binding of PFASs to proteins during placental transfer could be simulated by molecular docking and that the placental transfer efficiency of PFASs could also be predicted by machine learning. Therefore, future research on the maternal-fetal transfer mechanisms of PFASs with the benefit of simulation analysis approaches is warranted to provide a scientific basis for the health effects of PFASs on newborns.

Biomonitoring California Protocol for Following up on Elevated Levels of Urinary Arsenic

OBJECTIVES

to develop and implement a follow-up protocol for Biomonitoring California study participants with elevated levels of urinary arsenic, particularly inorganic forms.

METHODS

We selected 20 μg/L as the level of concern for urinary inorganic arsenic; samples with total arsenic ≥20 μg/L were speciated. Participants with elevated inorganic arsenic were notified of their level and invited to participate in a telephone survey to help determine possible exposure sources. We illustrate the protocol in four Biomonitoring California studies, which collected samples from 2010-2013 in locations across the state.

RESULTS

48 participants in the four studies had elevated urinary inorganic arsenic levels. Consumption of rice and rice-based products was the most commonly identified potential source of inorganic arsenic exposure.

CONCLUSIONS

Of 48 participants with elevated inorganic arsenic, 27 would have been missed if we had used the previously published threshold of 50 µg/L total arsenic to identify urine samples for speciation. This protocol fills a gap in the clinical literature by providing a more health-protective approach to identify individuals with elevated urinary inorganic arsenic and help determine potentially significant exposure sources.

A science-based agenda for health-protective chemical assessments and decisions: overview and consensus statement

The manufacture and production of industrial chemicals continues to increase, with hundreds of thousands of chemicals and chemical mixtures used worldwide, leading to widespread population exposures and resultant health impacts. Low-wealth communities and communities of color often bear disproportionate burdens of exposure and impact; all compounded by regulatory delays to the detriment of public health. Multiple authoritative bodies and scientific consensus groups have called for actions to prevent harmful exposures via improved policy approaches. We worked across multiple disciplines to develop consensus recommendations for health-protective, scientific approaches to reduce harmful chemical exposures, which can be applied to current US policies governing industrial chemicals and environmental pollutants. This consensus identifies five principles and scientific recommendations for improving how agencies like the US Environmental Protection Agency (EPA) approach and conduct hazard and risk assessment and risk management analyses: (1) the financial burden of data generation for any given chemical on (or to be introduced to) the market should be on the chemical producers that benefit from their production and use; (2) lack of data does not equate to lack of hazard, exposure, or risk; (3) populations at greater risk, including those that are more susceptible or more highly exposed, must be better identified and protected to account for their real-world risks; (4) hazard and risk assessments should not assume existence of a "safe" or "no-risk" level of chemical exposure in the diverse general population; and (5) hazard and risk assessments must evaluate and account for financial conflicts of interest in the body of evidence. While many of these recommendations focus specifically on the EPA, they are general principles for environmental health that could be adopted by any agency or entity engaged in exposure, hazard, and risk assessment. We also detail recommendations for four priority areas in companion papers (exposure assessment methods, human variability assessment, methods for quantifying non-cancer health outcomes, and a framework for defining chemical classes). These recommendations constitute key steps for improved evidence-based environmental health decision-making and public health protection.

Dietary predictors of prenatal per- and poly-fluoroalkyl substances exposure

BACKGROUND

Per- and poly-fluoroalkyl substances (PFAS) are commonly detected in a variety of foods and food packaging materials. However, few studies have examined diet as a potential source of PFAS exposure during pregnancy. In the present cross-sectional study, we examined prenatal PFAS levels in relation to self-reported consumption of meats, dairy products, and processed foods during pregnancy.

METHODS

Participants were enrolled in the Chemicals in Our Bodies study, a demographically diverse pregnancy cohort in San Francisco, CA (N = 509). Diet was assessed using a self-reported interview questionnaire administered during the second trimester. Participants were asked on average how many times a day, week, or month they ate 11 different foods since becoming pregnant. Responses were categorized as at least once a week or less than once a week and foods were grouped into three categories: processed foods, dairy products, and meats. Twelve PFAS (ng/mL) were measured in second trimester serum samples. We investigated relationships between consumption of individual dairy products, meats, and processed foods and natural log-transformed PFAS using separate linear regression models adjusted for maternal age, education, race/ethnicity, and nativity.

RESULTS

Seven PFAS were detected in ≥65% of participants. Consumption of dairy milk and cheese at least once per week was moderately associated with elevated levels of perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDeA) relative to those who ate dairy products less than once week. The strongest associations observed were with PFDeA for dairy milk (β = 0.2, 95% confidence interval [CI] = 0.02, 0.39) and PFNA for cheese (β = 0.22, 95% CI = 0.02, 0.41). Eating fish, poultry, and red meat at least once per week was associated with higher levels of perfluoroundecanoic acid, PFDeA, PFNA, and perflucorooctane sulfonic acid.

CONCLUSIONS

Results indicate that consumption of animal products may contribute to elevated prenatal PFAS levels.

Exposure to flame retardants in European children - Results from the HBM4EU aligned studies

Many legacy and emerging flame retardants (FRs) have adverse human and environmental health effects. This study reports legacy and emerging FRs in children from nine European countries from the HBM4EU aligned studies. Studies from Belgium, Czech Republic, Germany, Denmark, France, Greece, Slovenia, Slovakia, and Norway conducted between 2014 and 2021 provided data on FRs in blood and urine from 2136 children. All samples were collected and analyzed in alignment with the HBM4EU protocols. Ten halogenated FRs were quantified in blood, and four organophosphate flame retardants (OPFR) metabolites quantified in urine. Hexabromocyclododecane (HBCDD) and decabromodiphenyl ethane (DBDPE) were infrequently detected (<16% of samples). BDE-47 was quantified in blood from Greece, France, and Norway, with France (0.36 ng/g lipid) having the highest concentrations. BDE-153 and -209 were detected in <40% of samples. Dechlorane Plus (DP) was quantified in blood from four countries, with notably high median concentrations of 16 ng/g lipid in Slovenian children. OPFR metabolites had a higher detection frequency than other halogenated FRs. Diphenyl phosphate (DPHP) was quantified in 99% of samples across 8 countries at levels ∼5 times higher than other OPFR metabolites (highest median in Slovenia of 2.43 ng/g lipid). FR concentrations were associated with lifestyle factors such as cleaning frequency, employment status of the father of the household, and renovation status of the house, among others. The concentrations of BDE-47 in children from this study were similar to or lower than FRs found in adult matrices in previous studies, suggesting lower recent exposure and effectiveness of PBDE restrictions.

Associations of per- and polyfluoroalkyl substances (PFAS) and their mixture with oxidative stress biomarkers during pregnancy

BACKGROUND

Oxidative stress from excess reactive oxygen species (ROS) is a hypothesized contributor to preterm birth. Per- and polyfluoroalkyl substances (PFAS) exposure is reported to generate ROS in laboratory settings, and is linked to adverse birth outcomes globally. However, to our knowledge, the relationship between PFAS and oxidative stress has not been examined in the context of human pregnancy.

OBJECTIVE

To investigate the associations between prenatal PFAS exposure and oxidative stress biomarkers among pregnant people.

METHODS

Our analytic sample included 428 participants enrolled in the Illinois Kids Development Study and Chemicals In Our Bodies prospective birth cohorts between 2014 and 2019. Twelve PFAS were measured in second trimester serum. We focused on seven PFAS that were detected in >65 % of participants. Urinary levels of 8-isoprostane-prostaglandin-F2α, prostaglandin-F2α, 2,3-dinor-8-iso-PGF2α, and 2,3-dinor-5,6-dihydro-8-iso-PGF2α were measured in the second and third trimesters as biomarkers of oxidative stress. We fit linear mixed-effects models to estimate individual associations between PFAS and oxidative stress biomarkers. We used quantile g-computation and Bayesian kernel machine regression (BKMR) to assess associations between the PFAS mixture and averaged oxidative stress biomarkers.

RESULTS

Linear mixed-effects models showed that an interquartile range increase in perfluorooctane sulfonic acid (PFOS) was associated with an increase in 8-isoprostane-prostaglandin-F2α (β = 0.10, 95 % confidence interval = 0, 0.20). In both quantile g-computation and BKMR, and across all oxidative stress biomarkers, PFOS contributed the most to the overall mixture effect. The six remaining PFAS were not significantly associated with changes in oxidative stress biomarkers.

CONCLUSIONS

Our study is the first to investigate the relationship between PFAS exposure and biomarkers of oxidative stress during human pregnancy. We found that PFOS was associated with elevated levels of oxidative stress, which is consistent with prior work in animal models and cell lines. Future research is needed to understand how prenatal PFAS exposure and maternal oxidative stress may affect fetal development.

Modeling the transplacental transfer of small molecules using machine learning: a case study on per- and polyfluorinated substances (PFAS)

BACKGROUND

Despite their large numbers and widespread use, very little is known about the extent to which per- and polyfluoroalkyl substances (PFAS) can cross the placenta and expose the developing fetus.

OBJECTIVE

The aim of our study is to develop a computational approach that can be used to evaluate the of extend to which small molecules, and in particular PFAS, can cross to cross the placenta and partition to cord blood.

METHODS

We collected experimental values of the concentration ratio between cord and maternal blood (R_CM) for 260 chemical compounds and calculated their physicochemical descriptors using the cheminformatics package Mordred. We used the compiled database to, train and test an artificial neural network (ANN). And then applied the best performing model to predict R_CM for a large dataset of PFAS chemicals (n = 7982). We, finally, examined the calculated physicochemical descriptors of the chemicals to identify which properties correlated significantly with R_CM.

RESULTS

We determined that 7855 compounds were within the applicability domain and 127 compounds are outside the applicability domain of our model. Our predictions of R_CM for PFAS suggested that 3623 compounds had a log R_CM > 0 indicating preferable partitioning to cord blood. Some examples of these compounds were bisphenol AF, 2,2-bis(4-aminophenyl)hexafluoropropane, and nonafluoro-tert-butyl 3-methylbutyrate.

SIGNIFICANCE

These observations have important public health implications as many PFAS have been shown to interfere with fetal development. In addition, as these compounds are highly persistent and many of them can readily cross the placenta, they are expected to remain in the population for a long time as they are being passed from parent to offspring.

IMPACT

Understanding the behavior of chemicals in the human body during pregnancy is critical in preventing harmful exposures during critical periods of development. Many chemicals can cross the placenta and expose the fetus, however, the mechanism by which this transport occurs is not well understood. In our study, we developed a machine learning model that describes the transplacental transfer of chemicals as a function of their physicochemical properties. The model was then used to make predictions for a set of 7982 per- and polyfluorinated alkyl substances that are listed on EPA's CompTox Chemicals Dashboard. The model can be applied to make predictions for other chemical categories of interest, such as plasticizers and pesticides. Accurate predictions of R_CM can help scientists and regulators to prioritize chemicals that have the potential to cause harm by exposing the fetus.

Toxic Substances Control Act (TSCA) Implementation: How the Amended Law Has Failed to Protect Vulnerable Populations from Toxic Chemicals in the United States

Exposures to industrial chemicals are widespread and can increase the risk of adverse health effects such as cancer, developmental disorders, respiratory effects, diabetes, and reproductive problems. The amended Toxic Substances Control Act (amended TSCA) requires the U.S. Environmental Protection Agency (EPA) to evaluate risks of chemicals in commerce, account for risk to potentially exposed and susceptible populations, and mitigate risks for chemicals determined to pose an unreasonable risk to human health and the environment. This analysis compares EPA's first 10 chemical risk evaluations under amended TSCA to best scientific practices for conducting risk assessments. We find EPA's risk evaluations underestimated human health risks of chemical exposures by excluding conditions of use and exposure pathways; not considering aggregate exposure and cumulative risk; not identifying all potentially exposed or susceptible subpopulations, and not quantifying differences in risk for susceptible groups; not addressing data gaps; and using flawed systematic review approaches to identify and evaluate the relevant evidence. We present specific recommendations for improving the implementation of amended TSCA using the best available science to ensure equitable, socially just safeguards to public health. Failing to remedy these shortcomings will result in continued systematic underestimation of risk for all chemicals evaluated under amended TSCA.

Perspectives of peripartum people on opportunities for personal and collective action to reduce exposure to everyday chemicals: Focus groups to inform exposure report-back

Participants in biomonitoring studies who receive personal exposure reports seek information to reduce exposures. Many chemical exposures are driven by systems-level policies rather than individual actions; therefore, change requires engagement in collective action. Participants' perceptions of collective action and use of report-back to support engagement remain unclear. We conducted virtual focus groups during summer 2020 in a diverse group of peripartum people from cohorts in the Environmental influences on Child Health Outcomes (ECHO) Program (N = 18). We assessed baseline exposure and collective action experience, and report-back preferences. Participants were motivated to protect the health of their families and communities despite significant time and cognitive burdens. They requested time-conscious tactics and accessible information to enable action to reduce individual and collective exposures. Participant input informed the design of digital report-back in the cohorts. This study highlights opportunities to shift responsibility from individuals to policymakers to reduce chemical exposures at the systems level.

Multigenerational metabolic disruption: Developmental origins and mechanisms of propagation across generations

It has been long known that the environment plays a critical role in the etiology of disease. However, it is still unclear how the large variety of environmental factors humans are exposed to interact with each other to lead to disease. Metabolic disorders are just one example of human disorders that have been associated with environmental exposures. Obesity and type 2 diabetes have become a health and economic burden worldwide as the number of affected people has tripled in the last 40 years. Animal and human studies have shown a strong association between exposure to environmental chemicals during critical windows of susceptibility such as periconception, prenatal, and early life, whose effect can persist through development and across generations. However, little is known about the mechanisms driving this persistence. Here, we review historical and current knowledge on the effect of exposure to environmental factors during in utero development and discuss mechanisms for these disorders to be propagated across generations.

Enantioselective characteristics, bioaccumulation and toxicological effects of chlordane-related compounds in laying hens

Chlordane-related compounds are ubiquitously detected in the environment and can transfer and accumulate to animals through food chain to cause adverse effects. In this study, the dynamic distribution and the enantiomeric profile of chlordane-related compounds in laying hens over time were investigated. The effect of these compounds on immune-associated cells in the intestinal tract and histopathology in some tissues were also evaluated after long-term exposure. The chlordane-related compounds preferentially accumulated in fat, followed by the intestines, ovum, and egg yolk during long-term exposure. The metabolites heptachlor epoxide and oxychlordane were mainly formed in the liver of hens by epoxidation or hydroxylation. The high accumulation ratios of trans-nonachlor and MC5 were found in ovum and egg yolk after long-term exposure, implying a greater risk to the hens' offspring. Chlordane-related compounds may cause abnormal lipometabolism and glycometabolism in liver of hens. Additionally, (-)-Cis-chlordane was dominant in all tissues of laying hens and its dominance increased over time. Conversely, (+)-isomer of metabolite oxychlordane was overwhelmingly dominant during the experiment. These findings about enantioselectivity, metabolic processes and toxicological effects are crucial in understanding the exposure risk of chlordane-related compounds.

A Critical Review on Transplacental Transfer of Per- and Polyfluoroalkyl Substances: Prenatal Exposure Levels, Characteristics, and Mechanisms

Prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances (PFASs) has aroused public concerns as it can pose multiple health threats to pregnant women and cause adverse birth outcomes for fetuses. In previous studies, the prenatal exposure levels and transplacental transfer efficiencies (TTE) of PFASs have been reported and discussed. Specifically, the binding affinities between PFASs and some transporters were determined, demonstrating that the TTE values of PFASs are highly dependent on their binding behaviors. To summarize primary findings of previous studies and propose potential guidance for future research, this article provides a systematic overview on levels and characteristics of prenatal exposure to PFASs worldwide, summarizes relationships between TTE values and structures of PFASs, and discusses possible transplacental transfer mechanisms, especially for the combination between PFASs and transporters. Given the critical roles of transporters in the transplacental transfer of PFASs, we conducted molecular docking to further clarify the binding behaviors between PFASs and the selected transporters. We proposed that the machine learning can be a superior method to predict and reveal behaviors and mechanisms of the transplacental transfer of PFASs. In total, this is the first review providing a comprehensive overview on the prenatal exposure levels and transplacental transfer mechanisms of PFASs.

Prenatal PFAS and psychosocial stress exposures in relation to fetal growth in two pregnancy cohorts: Applying environmental mixture methods to chemical and non-chemical stressors

BACKGROUND

Prenatal exposure to individual per‑ and poly‑fluoroalkyl substances (PFAS) and psychosocial stressors have been associated with reductions in fetal growth. Studies suggest cumulative or joint effects of chemical and non-chemical stressors on fetal growth. However, few studies have examined PFAS and non-chemical stressors together as a mixture, which better reflects real life exposure patterns. We examined joint associations between PFAS, perceived stress, and depression, and fetal growth using two approaches developed for exposure mixtures.

METHODS

Pregnant participants were enrolled in the Chemicals in Our Bodies cohort and Illinois Kids Development Study, which together make up the ECHO.CA.IL cohort. Seven PFAS were previously measured in 2nd trimester maternal serum samples and were natural log transformed for analyses. Perceived stress and depression were assessed using self-reported validated questionnaires, which were converted to t-scores using validated methods. Quantile g-computation and Bayesian kernel machine regression (BKMR) were used to assess joint associations between PFAS, perceived stress and depression t-scores and birthweight z-scores (N = 876).

RESULTS

Individual PFAS, depression and perceived stress t-scores were negatively correlated with birthweight z-scores. Using quantile g-computation, a simultaneous one quartile increase in all PFAS, perceived stress and depression t-scores was associated with a slight reduction in birthweight z-scores (mean change per quartile increase = -0.09, 95% confidence interval = -0.21,0.03). BKMR similarly indicated that cumulative PFAS and stress t-scores were modestly associated with lower birthweight z-scores. Across both methods, the joint association appeared to be distributed across multiple exposures rather than due to a single exposure.

CONCLUSIONS

Our study is one of the first to examine the joint effects of chemical and non-chemical stressors on fetal growth using mixture methods. We found that PFAS, perceived stress, and depression in combination were modestly associated were lower birthweight z-scores, which supports prior studies indicating that chemical and non-chemical stressors are jointly associated with adverse health outcomes.

Perfluorohexane sulfonate induces memory impairment and downregulation of neuroproteins via NMDA receptor-mediated PKC-ERK/AMPK signaling pathway

Perfluorohexane sulfonate (PFHxS) is a widely used industrial chemical detected in human umbilical cord blood and breast milk, and has been suggested to exhibit developmental neurotoxicity. Previous studies on mice reported that neonatal exposure to PFHxS altered neuroprotein levels in the developing brain, and caused behavioral toxicity and cognitive dysfunction in the mature brain. However, the underlying mechanisms responsible for PFHxS-induced neuroprotein dysregulation are poorly understood. In this study, we examined the effect of neonatal exposure to PFHxS on memory function using an in vivo mice model. Furthermore, we examined the levels of growth associated protein-43 (GAP-43) and calcium/calmodulin dependent protein kinase II (CaMKII) (biomarkers of neuronal development) and the involved signaling pathways using differentiated neuronal PC12 cells. PFHxS decreased cell viability, GAP-43 and CaMKII levels, and neurite formation. These effects were mediated by the NMDA receptor, PKC-α, PKC-δ, AMPK and ERK pathways. MK801, an NMDA receptor antagonist, reduced the activation of PKC-α, PKC-δ, ERK and AMPK. The activation of ERK was suppressed by pharmacological and knockdown inhibition of PKC-α and -δ. Interestingly, the AMPK pathway was selectively inhibited by inhibiting PKC-δ but not PKC-ɑ. Consistent with PFHxS-induced neuronal death, and GAP-43 and CaMKII downregulation, neonatal exposure to PFHxS caused significant memory impairment in adult mice. Collectively, these results demonstrate that PFHxS induces persistent developmental neurotoxicity, as well as GAP-43 and CaMKII downregulation via the NMDA receptor-mediated PKCs (α and δ)-ERK/AMPK pathways.

The transplacental transfer efficiency of per- and polyfluoroalkyl substances (PFAS): a first meta-analysis

Per- and polyfluorinated substances (PFAS), ubiquitously present in the environment and biota, are transferred to the fetus via the placenta. PFAS can be distinguished, among other things, by their different carbon chain lengths and functional groups. The aim of this study was to provide comprehensive evidence on PFAS transfer rates across the human placental barrier by means of a meta-analysis based upon a systematic review. The available literature up to April 2021 was reviewed and transplacental transfer efficiencies (TTEs) of PFAS assessed. A total of 39 studies reporting data on 20 PFAS were included in the systematic review. Of these, 20 studies with data on 19 compounds were included in the meta-analysis. Comprehensive Meta-Analysis (CMA v3.0) was used for quantitative, statistical analyses with random effects models. A curvilinear relationship was found with short and long chains of perfluorocarboxylic acids (PFCAs) exhibiting higher TTE than compounds with intermediate chain length. Among the less well studied PFAS, perfluorohexanoic acid (PFHxA), 6:2 fluorotelomersulfonic acid (6:2 FTS) and perfluorobutanoic acid (PFBA) stood out the most with a high TEEs. The dependence of TTEs on chain length and functional group is clearly shown in this first meta-analysis on PFAS transfer across the human placenta. More data on effects of less well studied PFAS in pregnant women and neonates are needed to assess the potential risk for fetal exposure.

Joint effects of prenatal exposure to per- and poly-fluoroalkyl substances and psychosocial stressors on corticotropin-releasing hormone during pregnancy

BACKGROUND

Prenatal exposure to per- and poly-fluoroalkyl substances (PFAS) and psychosocial stressors has been associated with adverse pregnancy outcomes, including preterm birth. Previous studies have suggested that joint exposure to environmental chemical and social stressors may be contributing to disparities observed in preterm birth. Elevated corticotropin-releasing hormone (CRH) during mid-gestation may represent one biologic mechanism linking chemical and nonchemical stress exposures to preterm birth.

METHODS

Using data from a prospective birth cohort (N = 497), we examined the cross-sectional associations between five individual PFAS (ng/mL; PFNA, PFOA, PFOS, PFHxS, and Me-PFOSA-AcOH) and CRH (pg/mL) using linear regression. PFAS and CRH were measured during the second trimester in serum and plasma, respectively. Coefficients were standardized to reflect change in CRH associated with an interquartile range (IQR) increase in natural log-transformed PFAS. We additionally examined if the relationship between PFAS and CRH was modified by psychosocial stress using stratified models. Self-reported depression, stressful life events, perceived stress, food insecurity, and financial strain were assessed using validated questionnaires during the second trimester and included as binary indicators of psychosocial stress.

RESULTS

An IQR increase in PFNA was associated with elevated CRH (β = 5.17, 95% confidence interval [CI] = 1.79, 8.55). Increased concentrations of PFOA were also moderately associated with CRH (β = 3.62, 95% CI = -0.42, 7.66). The relationship between PFNA and CRH was stronger among women who experienced stressful life events, depression, food insecurity, and financial strain compared to women who did not experience these stressors.

CONCLUSIONS

This cross-sectional study is the first to examine the relationship between PFAS exposure and CRH levels in mid-gestation. We found that these associations were stronger among women who experienced stress, which aligns with previous findings that chemical and nonchemical stressor exposures can have joint effects on health outcomes.

Protracted Impairment of Maternal Metabolic Health in Mouse Dams Following Pregnancy Exposure to a Mixture of Low Dose Endocrine-Disrupting Chemicals, a Pilot Study

Pregnancy, a period of increased metabolic demands coordinated by fluctuating steroid hormones, is an understudied critical window of disease susceptibility for later-life maternal metabolic health. Epidemiological studies have identified associations between exposures to various endocrine-disrupting chemicals (EDCs) with an increased risk for metabolic syndrome, obesity, and diabetes. Whether such adverse outcomes would be heightened by concurrent exposures to multiple EDCs during pregnancy, consistent with the reality that human exposures are to EDC mixtures, was examined in the current pilot study. Mouse dams were orally exposed to relatively low doses of four EDCs: (atrazine (10 mg/kg), bisphenol-A (50 µg/kg), perfluorooctanoic acid (0.1 mg/kg), 2,3,7,8-tetrachlorodibenzo-p-dioxin (0.036 µg/kg)), or the combination (MIX), from gestational day 7 until birth or for an equivalent 12 days in non-pregnant females. Glucose intolerance, serum lipids, weight, and visceral adiposity were assessed six months later. MIX-exposed dams exhibited hyperglycemia with a persistent elevation in blood glucose two hours after glucose administration in a glucose tolerance test, whereas no such effects were observed in MIX-exposed non-pregnant females. Correspondingly, MIX dams showed elevated serum low-density lipoprotein (LDL). There were no statistically significant differences in weight or visceral adipose; MIX dams showed an average visceral adipose volume to body volume ratio of 0.09, while the vehicle dams had an average ratio of 0.07. Collectively, these findings provide biological plausibility for the epidemiological associations observed between EDC exposures during pregnancy and subsequent maternal metabolic dyshomeostasis, and proof of concept data that highlight the importance of considering complex EDC mixtures based of off common health outcomes, e.g., for increased risk for later-life maternal metabolic effects following pregnancy.

Distribution characteristics of per- and polyfluoroalkyl substances (PFASs) in human urines of acrylic fiber plant and chemical plant

Per- and polyfluoroalkyl substances (PFASs) are persistent and bioaccumulative substances that have many adverse effects on human bodies. This study investigated the PFASs distribution characteristics in urine samples of workers from an acrylic fiber plant and a chemical plant. It was found that perfluorobutanoic acid (PFBA) was the predominant PFASs both in urine samples from the chemical plant (detection frequency: 86.52%; median value: 39.01 ng/mL) and the acrylic fiber plant (detection frequency: 88.16%; median value: 44.36 ng/mL). Meanwhile, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were detected with very low frequencies and low concentrations. Furthermore, the results showed that PFASs levels in urine samples of workers from different units of the plants were quite different. PFASs concentrations of urine samples in males were higher than those in females, especially for PFBA, PFHxA, and PFDoA. The age had limited effects on the PFASs distribution in urine samples in this study, as short-chain PFASs were the dominant compounds. The correlations between PFASs concentrations in urine and gender/ages of workers were finally analyzed by Pearson correlation. The overall results may indicate that short-chain PFASs (such as: PFBA and PFBS) were becoming dominant for human exposure, especially occupational workers.

A Comprehensive Non-targeted Analysis Study of the Prenatal Exposome

Recent technological advances in mass spectrometry have enabled us to screen biological samples for a very broad spectrum of chemical compounds allowing us to more comprehensively characterize the human exposome in critical periods of development. The goal of this study was three-fold: (1) to analyze 590 matched maternal and cord blood samples (total 295 pairs) using non-targeted analysis (NTA); (2) to examine the differences in chemical abundance between maternal and cord blood samples; and (3) to examine the associations between exogenous chemicals and endogenous metabolites. We analyzed all samples with high-resolution mass spectrometry using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF/MS) in both positive and negative electrospray ionization modes (ESI+ and ESI-) and in soft ionization (MS) and fragmentation (MS/MS) modes for prioritized features. We confirmed 19 unique compounds with analytical standards, we tentatively identified 73 compounds with MS/MS spectra matching, and we annotated 98 compounds using an annotation algorithm. We observed 103 significant associations in maternal and 128 in cord samples between compounds annotated as endogenous and compounds annotated as exogenous. An example of these relationships was an association between three poly and perfluoroalkyl substances (PFASs) and endogenous fatty acids in both the maternal and cord samples indicating potential interactions between PFASs and fatty acid regulating proteins.

Developmental origins of metabolic diseases

Almost 2 billion adults in the world are overweight, and more than half of them are classified as obese, while nearly one-third of children globally experience poor growth and development. Given the vast amount of knowledge that has been gleaned from decades of research on growth and development, a number of questions remain as to why the world is now in the midst of a global epidemic of obesity accompanied by the "double burden of malnutrition," where overweight coexists with underweight and micronutrient deficiencies. This challenge to the human condition can be attributed to nutritional and environmental exposures during pregnancy that may program a fetus to have a higher risk of chronic diseases in adulthood. To explore this concept, frequently called the developmental origins of health and disease (DOHaD), this review considers a host of factors and physiological mechanisms that drive a fetus or child toward a higher risk of obesity, fatty liver disease, hypertension, and/or type 2 diabetes (T2D). To that end, this review explores the epidemiology of DOHaD with discussions focused on adaptations to human energetics, placental development, dysmetabolism, and key environmental exposures that act to promote chronic diseases in adulthood. These areas are complementary and additive in understanding how providing the best conditions for optimal growth can create the best possible conditions for lifelong health. Moreover, understanding both physiological as well as epigenetic and molecular mechanisms for DOHaD is vital to most fully address the global issues of obesity and other chronic diseases.

Mixture effects of prenatal exposure to per- and polyfluoroalkyl substances and polybrominated diphenyl ethers on maternal and newborn telomere length

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) and polybrominated diphenyl ethers (PBDEs) are endocrine disrupting chemicals with widespread exposures across the U.S. given their abundance in consumer products. PFAS and PBDEs are associated with reproductive toxicity and adverse health outcomes, including certain cancers. PFAS and PBDEs may affect health through alternations in telomere length. In this study, we examined joint associations between prenatal exposure to PFAS, PBDEs, and maternal and newborn telomere length using mixture analyses, to characterize effects of cumulative environmental chemical exposures.

METHODS

Study participants were enrolled in the Chemicals in Our Bodies (CIOB) study, a demographically diverse cohort of pregnant people and children in San Francisco, CA. Seven PFAS (ng/mL) and four PBDEs (ng/g lipid) were measured in second trimester maternal serum samples. Telomere length (T/S ratio) was measured in delivery cord blood of 292 newborns and 110 second trimester maternal whole blood samples. Quantile g-computation was used to assess the joint associations between groups of PFAS and PBDEs and newborn and maternal telomere length. Groups considered were: (1) all PFAS and PBDEs combined, (2) PFAS, and (3) PBDEs. Maternal and newborn telomere length were modeled as separate outcomes.

RESULTS

T/S ratios in newborn cord and maternal whole blood were moderately correlated (Spearman ρ = 0.31). In mixtures analyses, a simultaneous one quartile increase in all PFAS and PBDEs was associated with a small increase in newborn (mean change per quartile increase = 0.03, 95% confidence interval [CI] = -0.03, 0.08) and maternal telomere length (mean change per quartile increase = 0.03 (95% CI = -0.03, 0.09). When restricted to maternal-fetal paired samples (N = 76), increasing all PFAS and PBDEs combined was associated with a strong, positive increase in newborn telomere length (mean change per quartile increase = 0.16, 95% CI = 0.03, 0.28). These associations were primarily driven by PFAS (mean change per quartile increase = 0.11 [95% CI = 0.01, 0.22]). No associations were observed with maternal telomere length among paired samples.

CONCLUSIONS

Our findings suggest that PFAS and PBDEs may be positively associated with newborn telomere length.

Inflammatory state and autism-like behavioral phenotype of offspring induced by maternal exposure to low-dose chemical mixtures during pregnancy in mice

To investigate the effects of maternal exposure to 13 chemicals mixture (CM) during pregnancy on pregnancy outcome and health status of maternal/offspring mice. C57BL/6 pregnant mice were given drinking water containing carbaryl dimethoate glyphosate methomyl methyl parathion triadimefon aspartame sodium benzoate calcium disodium ethylene diamine tetra-acetate ethylparaben butylparaben bisphenol A and acacia gum The effects of CM exposure on pregnancy outcome, health status of dams/offspring, levels of circulating inflammatory cytokines in dams/offspring and emotional related behaviors of offspring were evaluated. CM exposure during pregnancy had no significant effect on pregnancy outcome, liver function, body weight of the dams in late pregnancy and uterine/ovarian weight after delivery, however, it led to an increase in maternal serum IFN-γ level （<0.05）. CM exposure during pregnancy had no significant effect on the liver function of offspring, but increased the serum IFN-γ, prefrontal cortex IFN-γ, and TNF-α and hippocampus IFN-γ levels in the offspring（all <0.01）. In addition, the offspring of CM group showed significant abnormal emotion-related (autism-like) behaviors in adulthood, especially in male offspring. Low dose CM exposure during pregnancy may induce inflammation status in dams/offspring, and lead to autism-like behaviors in offspring, indicating the potential effects of low dose CM exposure on human maternal and infant health.

Suspect Screening, Prioritization, and Confirmation of Environmental Chemicals in Maternal-Newborn Pairs from San Francisco

Our proof-of-concept study develops a suspect screening workflow to identify and prioritize potentially ubiquitous chemical exposures in matched maternal/cord blood samples, a critical period of development for future health risks. We applied liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (LC-QTOF/MS) to perform suspect screening for ∼3500 industrial chemicals on pilot data from 30 paired maternal and cord serum samples (n = 60). We matched 662 suspect features in positive ionization mode and 788 in negative ionization mode (557 unique formulas overall) to compounds in our database, and selected 208 of these for fragmentation analysis based on detection frequency, correlation in feature intensity between maternal and cord samples, and peak area differences by demographic characteristics. We tentatively identified 73 suspects through fragmentation spectra matching and confirmed 17 chemical features (15 unique compounds) using analytical standards. We tentatively identified 55 compounds not previously reported in the literature, the majority which have limited to no information about their sources or uses. Examples include (i) 1-(1-acetyl-2,2,6,6-tetramethylpiperidin-4-yl)-3-dodecylpyrrolidine-2,5-dione (known high production volume chemical) (ii) methyl perfluoroundecanoate and 2-perfluorooctyl ethanoic acid (two PFAS compounds); and (iii) Sumilizer GA 80 (plasticizer). Thus, our workflow demonstrates an approach to evaluating the chemical exposome to identify and prioritize chemical exposures during a critical period of development.

Transplacental Behaviors of Organophosphate Tri- and Diesters Based on Paired Human Maternal and Cord Whole Blood: Efficiencies and Impact Factors

Organophosphate tri- and diesters (tri-OPEs and di-OPEs) were quantified in 63 paired maternal and cord whole blood samples collected in Hubei, China, in which tri-o-cresyl phosphate (ToCP) was predominant. The transplacental transfer efficiencies (expressed as cord blood to maternal blood (C:M) concentration ratios) of aryl-tri-OPEs, such as ToCP (1.61) and triphenyl phosphate (TPHP) (1.06), were higher than those of alkyl-tri-OPEs (0.66-0.76). For the target tri-OPEs and some traditional organic compounds, the C:M ratios first increased with log K_ow in the range of 1.63-5.23 and then decreased, showing a parabolic relationship. However, ToCP, with a log K_ow of 6.34, deviated from this relationship and displayed the highest C:M ratio (1.61). Molecular docking indicated a very strong binding affinity between ToCP and transthyretin, suggesting that ToCP might be actively transported by transthyretin in the placenta. The di-OPE levels in the blood samples were significantly lower than the corresponding tri-OPE levels, and those in the cord blood were influenced not only by their transplacental behaviors but also by their low excretion rates and the metabolic characteristics of their parent compounds in the fetus. This study provides useful information for accurately assessing the health risks posed by tri-OPEs to pregnant women and fetuses.