Exposure characteristics of legacy and novel per- and polyfluoroalkyl substances in blood and association with hypertension among low-exposure population

The sex matters: sex-biased stimulatory responses to contaminants

Hormetic regulation is a health hallmark determining susceptibility and lifespan, through which whole-animal performance is also stimulated by low doses of chemical contaminants. However, the sex-dependence of these stimulatory responses remains poorly understood. In this perspective, we highlight compelling evidence of sex-dependent stimulation by contaminants across diverse animal taxa. These responses occur at concentrations below (subNOAEL) or above (superNOAEL, sublethal) established toxicological thresholds, influencing traits such as growth, body mass, survival, and lifespan in a sex-dependent manner. The underlying mechanisms, including gene expression regulation and antioxidant capacity, often vary between sexes. While biphasic hormetic dose-response relationships are commonly observed, emerging evidence suggests that triphasic dose-response patterns may also occur and differ between sexes. The triphasic responses include the hormetic zone with stimulations, a sub-hormetic zone with potential negative effects, and a super-hormetic zone with adverse effects. Interestingly, the observed sex-biased responses often favor females, underscoring the need for further research. However, stimulations do not necessarily indicate beneficial effects and may introduce 'hidden' risks that warrant further long-term investigations integrating multiple dimensions such as resistance to disease or toxicity, metabolic efficiency and weight gain, and reproductive output. Understanding these phenomena is essential for improving ecological risk assessments, refining prevention and treatment strategies, and fostering resilience in affected organisms.

Age-specific associations between per- and polyfluoroalkyl substances exposure and metabolic syndrome: a cross-sectional study

BACKGROUND

The widespread presence of per-and polyfluoroalkyl substances (PFAS) has raised global health concerns. This study aims to determine the age-specific relationships of PFAS compounds with metabolic syndrome (MetS) and its components.

METHODS

We used data from the National Health and Nutrition Examination Survey (NHANES) in 2003-2018. Modified Poisson regression was employed to estimate associations between individual PFAS compounds and prevalence of MetS, as well as its components. Multiple linear regression analyses were performed to examine the associations between PFAS congeners and metabolic markers, including lipid and glucose homeostasis traits. Additionally, weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) models were conducted to investigate the joint effects of PFAS mixtures on the prevalence of MetS and its components across different age groups.

RESULTS

A total of 5850 participants were included for analysis. In the Modified Poisson regression model, ln-transformed perfluorononanoic acid (PFNA) level was positively correlated with MetS prevalence in adolescents (prevalence ratio [PR] = 1.42; 95% CI: 1.01-1.99). Conversely, ln-transformed perfluorohexanesulfonic acid (PFHxS) and ln-transformed 2-(N-Methylperfluorooctane sulfonamido) acetic acid (MeFOSAA) were negatively associated with the risks of MetS in young adults (PR = 0.86, 95% CI: 0.76-0.98) and middle-aged adults (PR = 0.88, 95% CI: 0.79-0.98), respectively. Notably, individual PFAS exposure was positively associated with levels of total cholesterol, low-density lipoprotein, non-high-density lipoprotein, and high-density lipoprotein in young and middle-aged adults. However, overall effect analyses using WQS and BKMR showed no significant associations of PFAS mixture with MetS in any age group. Nonetheless, in middle-aged adults, PFAS mixture was adversely correlated with hypertriglyceridemia and positively linked to a greater risk of hypertension and increased high-density lipoprotein cholesterol levels.

CONCLUSIONS

Our study highlighted the complex relationships between PFAS exposure and the risks of MetS and its components across different age groups. Co-exposure to PFAS was particularly linked to dyslipidemia in young and middle-aged adults. Prospective studies are needed for better comprehension of the causative impact of PFAS on the risks of MetS.

When subcellular chemical imaging enlightens our understanding on intestinal absorption, intracellular fate and toxicity of PFOA in vitro

Perfluorooctanoic acid (PFOA) is a persistent organic pollutant that accumulates in the human body, leading to major health issues. Upon oral uptake, the gastrointestinal tract is the first biological barrier against PFOA. However, the localization of PFOA and its impact on the intestinal wall are largely unknown. Here we achieve a breakthrough in the knowledge of intestinal absorption, intracellular fate and toxicity of PFOA using in vitro assays combined with novel analytical imaging techniques. For the first time, we localized PFOA in the cytosol of Caco-2 cells after acute exposure using high spatial resolution mass spectrometry imaging, and we estimated the PFOA cytosolic concentration. Knowing that PFOA enters and accumulates in the intestinal cells, we also performed common toxicity assays assessing cell metabolic activity, membrane integrity, oxidative stress response, and cell respiration. This study integrating powerful analytical techniques with widely used toxicology assays provides insightful information to better understand potential negative impacts of PFOA and opens new opportunities in toxicology and life science in general.

Efficient removal of per- and polyfluoroalkyl substances by a metal-organic framework membrane with high selectivity and stability

Per- and polyfluoroalkyl substances (PFAS) in water requires sufficient removal due to their extreme chemical stability and potential health risk. Membrane separation can be a promising strategy, while membranes with conventional structures used for PFAS removal often face challenges such as limited efficiency and stability. In this study, a novel metal-organic framework (MOF) membrane with local modification of polyamide (PA) was developed by introducing interfacial polymerization process during the construction of lamellar membranes with MOF nanosheets. Benefiting from the dense structure and strong negative surface charge, the PA-modified MOF membrane could effectively remove 11 types of PFAS (five short-chain and six long-chain ones with molecular weights ranging from 214.0 to 514.1 Da), especially displaying high rejections for short-chain PFAS (over 84%), along with a remarkable water permeance of 21.4 L·m⁻²·h⁻¹·bar⁻1. The membrane removal characteristics for PFAS were deeply analyzed by elucidating various rejection mechanisms, with particularly distinguishing the rejection and adsorption capacity. Moreover, the membrane stability was significantly enhanced, demonstrated by the structural integrity after 10 min of ultrasonic treatment and stable separation efficiency over 120 h of continuous filtration. With enhanced surface hydrophilicity and negative charge as well as dense membrane pores, the novel membrane also exhibited more superior anti-fouling performance compared to conventional lamellar and PA membranes, further manifesting advantages for practical applications. This work provides a promising solution for developing high-performance membranes tailored specifically for efficient PFAS removal, addressing a critical need in water treatment.

Exposure to per- and polyfluoroalkyl substances is associated with impaired cardiovascular health: a cross-sectional study

Background

Per- and polyfluoroalkyl substance (PFAS) exposure and cardiovascular disease are controversial. We aimed to assess the association between serum PFAS exposure and cardiovascular health (CVH) in U.S. adults.

Methods

We analyzed serum PFAS concentration data of U.S. adults reported in the National Health and Nutrition Examination Survey (NHANES) study (2005-2018). We employed two weighted logistic regression models and a restricted cubic spline (RCS) to examine the association between each PFAS and impaired CVH (defined as moderate and low CVH). Quantile g-computation (Qgcomp) and weighted quantile sum (WQS) analysis were used to estimate the effects of mixed exposures to PFASs on impaired CVH.

Results

PFAS were associated with an increased risk of impaired CVH (ORPFNA: 1.40, 95% CI: 1.09, 1.80; ORPFOA: 1.44, 95% CI: 1.10, 1.88; ORPFOS: 1.62, 95% CI: 1.25, 2.11). PFOA and PFOS exhibited nonlinear relationships with impaired CVH. Significant interactions were observed for impaired CVH between race/ethnicity and PFHxS (p = 0.02), marital status and PFOA (p = 0.03), and both marital status and race/ethnicity with PFOS (p = 0.01 and p = 0.02, respectively). Analysis via WQS and Qgcomp revealed that the mixture of PFAS was positively associated with an increased risk of impaired CVH.

Conclusion

PFNA, PFOA, and PFOS exposure are associated with an increased risk of impaired CVH in U.S. adults. Race/ethnicity and marital status may influence CVH. Reducing PFAS exposure could alleviate the burden of disease associated with impaired CVH.

Association between Serum 6:2 Chlorinated Polyfluorinated Ether Sulfonate Concentrations and Lung Cancer

6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) exhibits pronounced estrogenic effects, potentially influencing the etiology of lung cancer. This study assessed the potential associations between serum concentrations of 6:2 Cl-PFESA and lung cancer risk at the population level. Odds ratios (ORs) for lung cancer across serum 6:2 Cl-PFESA quartiles were assessed using conditional logistic regression. Additionally, we investigated potential effect modification by various confounding factors. Elevated serum levels of 6:2 Cl-PFESA were consistently associated with an increased risk of lung cancer in both the crude model (OR = 1.62, 95% CI: 1.08-2.42, p = 0.018) and the adjusted model (OR = 1.59, 95% CI: 1.06-2.39, p = 0.026). Stratified analyses revealed that elevated serum levels of 6:2 Cl-PFESA were associated with increased risk estimates of lung cancer among males (adjusted OR = 2.04, 95% CI: 1.19-3.51, p = 0.006), smokers (adjusted OR = 2.48, 95% CI: 1.25-4.89, p = 0.003), and drinkers (adjusted OR = 2.20, 95% CI: 0.94-5.16, p = 0.049). The results of this study imply that exposure to 6:2 Cl-PFESA at levels considered environmentally relevant may be linked to an elevated risk of developing lung cancer.

Exposure to per- and polyfluoroalkyl substance and metabolic syndrome: A nationally representative cross-sectional study from NHANES, 2003-2018

Per- and polyfluoroalkyl substances(PFAS) are widespread organic pollutants with endocrine-disrupting effects on human health, but the association of PFAS exposure with metabolic syndrome remains conflicting. National Health and Nutrition Examination Survey(NHANES) program was utilized to evaluate the association of individual PFAS exposure and metabolic disorders and further determined the joint effect of PFAS co-exposures. 13921 participants and five PFAS exposures(PFHxS, MPAH, PFDE, PFNA, and PFUA) were included for analysis. The association between individual PFAS and metabolic syndrome varied in the specific PFAS and the specific metabolic disorder examined. PFHxS was negatively associated with obesity(Q4; OR = 0.75; P < 0.001), but positively associated with hyperlipidemia (Q3; OR = 1.2; P = 0.013). PFUA was negatively associated with obesity (Q4; OR = 0.6; P < 0.001), hyperlipidemia (Q3; OR = 0.85; P = 0.03), and non-alcoholic fatty liver disease (NAFLD, Q4; OR = 0.64; P = 0.015), but positively associated with hyperglycemia(Q3; OR = 1.27; P = 0.004). Furthermore, PFAS co-exposures were negatively associated with obesity(OR = 0.63; P < 0.001) and NAFLD(OR = 0.85; P = 0.021), and positively associated with hyperlipidemia(OR = 1.05; P = 0.022), but not significantly associated with hyperglycemia or hypertension. Overall, there was a negative association between PFAS co-exposures and metabolic severity score(β = -0.15; P < 0.001). Subgroup analysis stratified by gender and obesity consistently showed the negative association of PFAS co-exposures with metabolic severity score, and the positive association with hyperlipidemia. However, subgroup analysis showed a negative association with NAFLD in females but not in males, and a negative association with hyperglycemia in the obesity group, but not in the non-obesity group. Collectively, our study showed a negative association of PFAS co-exposures with metabolic syndrome severity score, but did not support a consistent association between PFAS co-exposures and individual components of metabolic syndrome. Additionally, there were gender-specific as well as BMI-specific differences in these associations. Further studies are needed to rule out the reverse causality and clarify the relationship of PFAS co-exposures with the specific metabolic disorder.