The role of exposure to per- and polyfluoroalkyl substances in racial/ethnic disparities in hypertension: Results from the study of Women's health across the nation

Specific and potent inhibition of steroid hormone pre-receptor regulator AKR1C2 by perfluorooctanoic acid: Implications for androgen metabolism

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental pollutants that are highly stable synthetic organofluorine compounds. One congener perfluorooctanoic acid (PFOA) can be detected in nearly all humans and is recognized as an endocrine disrupting chemical (EDC). EDCs disrupt hormone synthesis and metabolism and receptor function. One mechanism of steroid hormone action is the pre-receptor regulation of ligand access to steroid hormone receptors by aldo-keto reductases. Here we report PFOA inhibition of AKR family 1 member C2 (AKR1C2), leading to dysregulation of androgen action. Spectrofluorimetric inhibitor screens identified PFOA as a competitive and tight binding inhibitor of AKR1C2, whose role is to inactivate 5α-dihydrotestosterone (5α-DHT). Further site directed mutagenesis studies along with molecular docking simulations revealed the importance of residue Valine 54 in mediating AKR1C2 inhibitor specificity. Binding site restrictions were explored by testing inhibition of other related PFAS chemicals, confirming that steric hinderance is a key factor. Furthermore, radiochromatography using HPLC and in line radiometric detection confirmed the accumulation of 5α-DHT as a result of PFOA inhibition of AKR1C2. We showed that PFOA could enhance the transactivation of AR in reporter genes assays in which 5α-DHT metabolism was blocked by AKR1C2 inhibition in HeLa cells. Taken together, these data suggest PFOA has a role in disrupting androgen action through inhibiting AKR1C2. Our work identifies an EDC function for PFOA not previously revealed.

Associations of PFAS concentrations during pregnancy and midlife with bone health in midlife: Cross-sectional and prospective findings from Project Viva

BACKGROUND

PFAS may impair bone health, but effects of PFAS exposure assessed during pregnancy and the perimenopause-life stages marked by rapidly changing bone metabolism-on later life bone health are unknown.

METHODS

We studied 531 women in the Boston-area Project Viva cohort. We used multivariable linear, generalized additive, and mixture models to examine associations of plasma PFAS concentrations during early pregnancy [median (IQR) maternal age 32.9 (6.2) years] and midlife [age 51.2 (6.3)] with lumbar spine, total hip, and femoral neck areal bone mineral density (aBMD) and bone turnover biomarkersassessed in midlife. We examined effect modification by diet and physical activity measured at the time of PFAS exposure assessment and by menopausal status in midlife.

RESULTS

Participants had higher PFAS concentrations during pregnancy [1999-2000; e.g., PFOA median (IQR) 5.4 (3.8) ng/mL] than in midlife [2017-2021; e.g.

, PFOA

1.5 (1.2) ng/mL]. Women with higher PFOA, PFOS and PFNA during pregnancy had higher midlife aBMD, especially of the spine [e.g., 0.28 (95% CI: 0.07, 0.48) higher spine aBMD T-score, per doubling of PFOA], with stronger associations observed among those with higher diet quality. In contrast, higher concentrations of all PFAS measured in midlife were associated with lower concurrent aBMD at all sites [e.g., -0.21 (-0.35, -0.07) lower spine aBMD T-score, per doubling of PFOA]; associations were stronger among those who were postmenopausal. The associations of several PFAS with bone resorption (loss) were also stronger among postmenopausal versus premenopausal women.

DISCUSSION

Plasma PFAS measured during pregnancy versus in midlife had different associations with midlife aBMD. We found an adverse association of PFAS measured in midlife with midlife aBMD, particularly among postmenopausal women. Future studies with longer follow-up are needed to elucidate the effect of PFAS on bone health during the peri- and postmenopausal years.

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.

Associations of Prenatal Per- and Polyfluoroalkyl Substance (PFAS) Exposures with Offspring Adiposity and Body Composition at 16-20 Years of Age: Project Viva

BACKGROUND

Findings on the associations between prenatal PFAS exposures and offspring adiposity are inconsistent. Whether such associations may extend to adolescence is especially understudied.

OBJECTIVES

We investigated associations of prenatal PFAS exposures with offspring adiposity and body composition at 16-20 years of age.

METHODS

We studied 545 mother-child pairs in the prospective prebirth cohort Project Viva (Boston, Massachusetts). We measured six PFAS (PFOA, PFOS, PFNA, PFHxS, EtFOSAA, and MeFOSAA) in maternal early pregnancy (median age = 9.6 wk , range: 5.7-19.6 wk) plasma samples. At the late adolescence visit (median age = 17.4 y, range: 15.9-20.0 y), we obtained anthropometric measures and assessed body composition using bioelectrical impedance analysis and dual-energy X-ray absorptiometry. We examined associations of individual PFAS with obesity [i.e., age- and sex-specific body mass index (BMI) ≥ 95 th percentile] and adiposity and body composition using multivariable Poisson and linear regression models, respectively. We assessed PFAS mixture effects using Bayesian kernel machine regression (BKMR) and quantile g-computation. We used fractional-polynomial models to assess BMI trajectories (at 3-20 years of age) by prenatal PFAS levels.

RESULTS

Thirteen percent (n = 73 ) of the children had obesity in late adolescence. After multivariable adjustment, higher prenatal PFAS concentrations were associated with higher obesity risk [e.g., 1.59 (95% CI: 1.19, 2.12), 1.24 (95% CI: 0.98, 1.57), and 1.49 (95% CI: 1.11, 1.99) times the obesity risk per doubling of PFOS, PFOA, and PFNA, respectively]. BKMR showed an interaction between PFOA and PFOS, where the positive association between PFOS and obesity was stronger when PFOA levels were lower. Each quartile increment of the PFAS mixture was associated with 1.52 (95% CI: 1.03, 2.25) times the obesity risk and 0.52 (95% CI: - 0.02 , 1.06) kg / m 2 higher BMI. Children with higher prenatal PFOS, EtFOSAA, and MeFOSAA concentrations had higher rates of BMI increase starting from 9-11 years of age.

DISCUSSION

Prenatal PFAS exposures may have obesogenic effects into late adolescence. https://doi.org/10.1289/EHP12597.

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.

Association between prenatal exposure to perfluoroalkyl substance mixtures and intrauterine growth restriction risk: A large, nested case-control study in Guangxi, China

Intrauterine growth restriction (IUGR) is an abnormal fetal growth pattern that can lead to neonatal morbidity and mortality. IUGR may be affected by prenatal exposure to environmental pollutants, including perfluoroalkyl substances (PFASs). However, research linking PFAS exposure to IUGR is limited, with inconsistent results. We aimed to investigate the association between PFAS exposure and IUGR by using nested casecontrol study based on Guangxi Zhuang Birth Cohort (GZBC), in Guangxi, China. A total of 200 IUGR cases and 600 controls were enrolled in this study. The maternal serum concentrations of nine PFASs were measured using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLCMS). The associations single and mixed effects of prenatal PFAS exposure on IUGR risk were assessed using conditional logistic regression (single-exposure), Bayesian kernel machine regression (BKMR) and quantile g-computation (qgcomp) models. In the conditional logistic regression models, the log10-transformed concentrations of perfluoroheptanoic acid (PFHpA, adjusted OR: 4.41, 95% CI: 3.03-6.41), perfluorododecanoic acid (PFDoA, adjusted OR: 1.94, 95% CI: 1.14-3.32), and perfluorohexanesulfonate (PFHxS, adjusted OR: 1.83, 95% CI: 1.15-2.91) were positively associated with risk of IUGR. In the BKMR models, the combined effect of PFASs was positively associated with IUGR risk. In the qgcomp models, we also found an increased IUGR risk (OR=5.92, 95% CI: 2.33-15.06) when all nine PFASs increased by one tertile as a whole, and PFHpA (43.9%) contributed the largest positive weights. These findings suggested prenatal exposure to single and mixtures of PFASs may increase IUGR risk, with the effect being largely driven by the PFHpA concentration.