Exposure to per- and Polyfluoroalkyl Substances and Markers of Liver Injury: A Systematic Review and Meta-Analysis

Associations between per- and polyfluoroalkyl substances exposure and renal function as well as poor prognosis in chronic kidney disease patients

OBJECTIVES

The objectives of this study were to investigate the associations of single and mixed exposure to the environmental pollutants per- and polyfluoroalkyl substances (PFAS) with renal function and mortality in non-dialysis chronic kidney disease (CKD) patients.

METHODS

Non-dialysis CKD1-4 stage patients in the 2003-2018 US National Health and Nutrition Examination Survey (NHANES) who were ≥20 years old were included. Five PFAS were measured and all patients were followed up till 31 December 2019. Multivariate linear, logistic, and Cox regressions were used to evaluate the associations between PFAS exposure and renal function, mortality. Stratified subgroups were analyzed based on baseline characteristics. Bayesian kernel machine regression (BKMR) was used in sensitivity analysis.

RESULTS

Among 1503 CKD patients included, baseline renal function declined in 701 patients (44.4%) and 462 patients (24.9%) died during the follow-up. Single exposure to perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), and perfluorohexane sulfonic acid (PFHxS) was positively associated with renal function decline (p < .05). Mixed exposure to five kinds of PFAS was found to be associated with renal function decline. Restricted cubic spline (RCS) showed only PFOS had an inverted U-shaped association with renal function decline (p non-linear < .05). There was no statistically significant association between PFAS exposure and mortality. Urinary protein and drug use might interact with the associations between PFAS and renal function.

CONCLUSIONS

PFAS single and mixed exposure were closely related to renal function and renal progression in adult CKD patients. There was no statistically significant association between PFAS exposure and mortality.

Association between per- and polyfluoroalkyl substances with serum hepatobiliary system function biomarkers in patients with acute coronary syndrome

Previous studies have suggested that abnormal hepatobiliary system function may contribute to poor prognosis in patients with acute coronary syndrome (ACS) and that abnormal hepatobiliary system function may be associated with per- and polyfluoroalkyl substances (PFAS) exposure. However, there is limited evidence for this association in cardiovascular subpopulations, particularly in the ACS patients. Therefore, we performed this study to evaluate the association between plasma PFAS exposure and hepatobiliary system function biomarkers in patients with ACS. This study included 546 newly diagnosed ACS patients at the Second Hospital of Hebei Medical University, and data on 15 hepatobiliary system function biomarkers were obtained from medical records. Associations between single PFAS and hepatobiliary system function biomarkers were assessed using multiple linear regression models and restricted cubic spline model (RCS), and mixture effects were assessed using the Quantile g-computation model. The results showed that total bile acids (TBA) was negative associated with perfluorohexane sulfonic acid (PFHxS) (-7.69 %, 95 % CI: -12.15 %, -3.01 %). According to the RCS model, linear associations were found between TBA and PFHxS (P for overall = 0.003, P for non-linear = 0.234). We also have observed the association between between PFAS congeners and liver enzyme such as aspartate aminotransferase (AST) and α-l-Fucosidase (AFU), but it was not statistically significant after correction. In addition, Our results also revealed an association between prealbumin (PA) and PFAS congeners as well as mixtures. Our findings have provided a piece of epidemiological evidence on associations between PFAS congeners or mixture, and serum hepatobiliary system function biomarkers in ACS patients, which could be a basis for subsequent mechanism studies.

Effect of PFAS serum exposure pattern on the lipid metabolism: Time to step-forward in causal inference in epidemiology

Associations of per- and polyfluoroalkyl substances (PFAS) on lipid metabolism have been documented but research remains scarce regarding effect of PFAS on lipid variability. To deeply understand their relationship, a step-forward in causal inference is expected. To address these, we conducted a longitudinal study with three repeated measurements involving 201 participants in Beijing, among which 100 eligible participants were included for the present study. Twenty-three PFAS and four lipid indicators were assessed at each visit. We used linear mixed models and quantile g-computation models to investigate associations between PFAS and blood lipid levels. A latent class growth model described PFAS serum exposure patterns, and a generalized linear model demonstrated associations between these patterns and lipid variability. Our study found that PFDA was associated with increased TC (β = 0.083, 95% CI: 0.011, 0.155) and HDL-C (β = 0.106, 95% CI: 0.034, 0.178). The PFAS mixture also showed a positive relationship with TC (β = 0.06, 95% CI: 0.02, 0.10), with PFDA contributing most positively. Compared to the low trajectory group, the middle trajectory group for PFDA was associated with VIM of TC (β = 0.756, 95% CI: 0.153, 1.359). Furthermore, PFDA showed biological gradients with lipid metabolism. This is the first repeated-measures study to identify the impact of PFAS serum exposure pattern on the lipid metabolism and the first to estimate the association between PFAS and blood lipid levels in middle-aged and elderly Chinese and reinforce the evidence of their causal relationship through epidemiological studies.

Mitigation of PFAS toxicity through sorbent treatment in Sprague-Dawley rats during prenatal and postnatal exposure

PFAS (per- and polyfluoroalkyl substances) are prevalent and persistent environmental pollutants with significant toxicity, especially during critical windows of exposure such as pregnancy and lactation. This study investigated the prenatal and postnatal effects of PFAS exposure on the serum and liver of Sprague-Dawley rats, and the mitigating efficacy of orally administered sorbents. Animal groups included vehicle control, PFAS (0.95 mg/kg-bw/day), and PFAS co-treated with calcium montmorillonite (CM), CM-carnitine, CM-choline, activated carbon (AC), or acid processed montmorillonite (APM). Oral administration of PFAS resulted in accumulation in serum and liver by postnatal day (PND) 21, especially for PFOS. PFAS exposure also reduced body weight gain by 24 % in females and 35 % in males via reduced food and water conversion rates, impaired liver histopathological structure, caused hepatocellular hypertrophy, disrupted serum biochemistry, and reduced vitamins A and B2 in both sexes. Additionally, PFAS exposure increased oxidative stress and liver damage as evidenced by reduced antioxidants (GSH, SOD, GST), induced ALT, AST and pro-inflammatory cytokines (TGF-β and TNF-α), and suppressed CRP. Importantly, CM-carnitine and CM-choline were the most effective mitigating sorbents, significantly reducing PFAS bioavailability in the liver and serum and restoring biochemical parameters such as cholesterol, total protein, and glucose in serum. All sorbent treatments alleviated oxidative stress, normalized inflammatory markers, and improved nutrient levels in both serum and liver. Furthermore, the study revealed sex-specific responses, with females showing greater susceptibility to PFAS-induced metabolic changes and a more prominent response to sorbent mitigation. This study highlights the toxic effect of PFAS exposure in serum and liver during vulnerable windows of exposure such as pregnancy and lactation, and establishes the proof of concept for the oral administration of sorbents, particularly CM-carnitine, CM-choline, and a mixture of sorbents, as preventive mitigation strategies.

Explainable machine learning models enhance prediction of PFAS bioactivity using quantitative molecular surface analysis-derived representation

The extensive use of per- and polyfluoroalkyl substances (PFAS) in industrial and consumer products poses health risks due to their toxicity. Computational toxicology approaches, particularly quantitative structure-activity relationship (QSAR) models are essential for predicting PFAS bioactivity. However, established QSAR models including machine learning-based ones with traditional molecular descriptors such as constitutional, topological, and geometric descriptors, have limited predictive capability and interpretability. Herein, we proposed a novel machine learning approach that leverages quantitative molecular surface analysis (QMSA) of molecular electrostatic potential. Using QMSA descriptors, five machine learning models (e.g., random forest) achieved outstanding performance, with best accuracy of 0.950 ± 0.017, AUC-ROC of 0.938 ± 0.012, F1-score of 0.734 ± 0.024, and MCC of 0.684 ± 0.111 for five targets (tyrosyl-DNA phosphodiesterase 1 in the absence/presence of camptothecin, ATXN2 protein, transcription factor SMAD3, and transcription factor NRF2), which outperform previously reported models. SHAP analyses revealed that estimated density, molecular volume, positive surface area, and nonpolar surface area were the most important descriptors. These descriptors were deeply involved in PFAS binding to target proteins via non-covalent interactions as evidenced by molecular docking and molecular dynamics simulations. Our results demonstrated that QMSA descriptors-based machine learning models are capable of predicting PFAS toxicity with extraordinary performance and interpretability. This study provides a novel machine learning framework for the high-throughput and cost-effective screening of high-risk emerging PFAS in aquatic environments. By identifying the contaminants that should be prioritized for regulation and treatment among the growing number of PFAS, our work aids in water quality monitoring and risk assessment, and guides decision-making in aquatic environmental management. Furthermore, this work enhances our understanding of the molecular mechanisms involved in PFAS bioactivity.

Shining a light on environmental science: Recent advances in SERS technology for rapid detection of persistent toxic substances

Persistent toxic substances (PTS) represent a paramount environmental issue in the 21st century. Understanding the concentrations and forms of PTS in the environment is crucial for accurately assessing their environmental health impacts. This article presents a concise overview of the components of PTS, pertinent environmental regulations, and conventional detection methodologies. Additionally, we offer an in-depth review of the principles, development, and practical applications of surface-enhanced Raman scattering (SERS) in environmental monitoring, emphasizing the advancements in detecting trace amounts of PTS in complex environmental matrices. Recent progress in enhancing SERS sensitivity, improving selectivity, and practical implementations are detailed, showcasing innovative materials and methods. Integrating SERS with advanced algorithms are highlighted as pivotal areas for future research.

Association between per- and polyfluoroalkyl substances and unexplained recurrent spontaneous abortion: A case-control study in China

Although prior studies have identified that per- and polyfluoroalkyl substances (PFASs) were associated with adverse pregnancy outcomes, the potential influence of PFASs exposure on unexplained recurrent spontaneous abortion (URSA) remains uncertain. Our case-control study aimed to explore the associations between PFASs and URSA, including 110 URSA cases and 91 controls from Beijing. Concentrations of 15 PFASs in serum were measured using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The associations between PFASs and the risk of URSA were then analyzed using multiple logistic regression. Compared to the lowest tertile, PFBA (2nd (OR: 4.26; 95 % CI: 1.92, 9.45), 3rd (OR: 8.10; 95 % CI: 3.48, 18.89)), PFDoDA (2nd (OR: 2.17; 95 % CI: 1.72, 4.35), 3rd (OR: 3.18; 95 % CI: 2.24, 4.85)), PFHxS (3rd (OR: 2.46; 95 % CI: 1.15, 5.25) and PFHpS (3rd (OR: 2.56; 95 % CI: 1.15, 5.69) were positively associated with higher risks of URSA. 6:2 Cl-PFESA was significantly associated with decreased risks of URSA. Weighted quantile sum (WQS) regression analyses, Quantile g-computation (QGC) and Bayesian kernel machine regression (BKMR) identified PFBA and PFDoDA as the primary contributors to the mixed effects of PFASs on URSA. We found that maternal serum PFASs, especially PFBA and PFDoDA may increase the risk of URSA.

Short-chain per- and polyfluoroalkyl substances associate with elevated alanine aminotransferase: Cross-sectional analysis results from the STRIVE cohort

BACKGROUND

The impact of short-chain, low molecular weight polyfluoroalkyl substances (PFAS) and long-chain, high molecular weight PFAS on elevated alanine aminotransferase (ALT) remains unclear. Additionally, demographic and behavioral factors influencing PFAS levels in the U.S. population are not well understood.

OBJECTIVES

To examine (1) associations between short- and long-chain PFAS mixtures and elevated ALT, and (2) participant characteristics linked to PFAS levels.

METHODS

This study included 378 adults (196 with detailed liver disease evaluations and 135 with cirrhosis), aged 40-75 years, from the Southern Liver Health Study (STRIVE), an ongoing prospective cohort. Logistic regression assessed associations between serum PFAS and elevated ALT. Quantile g-computation evaluated PFAS mixture effects, while linear regression identified demographic and behavioral factors linked to PFAS levels.

RESULTS

A one-quartile increase in short-chain PFAS mixture levels was associated with higher odds of elevated ALT (adjusted odds ratio [aOR], 95% confidence interval [CI]: 2.14, 1.31-3.50; P=0.002) and higher log-transformed ALT levels (adjusted β, 95% CI: 0.09, 0.01-0.17; P=0.02). Long-chain PFAS mixtures showed no significant association. Individually, perfluoroheptanoic acid (a short-chain PFAS) (aOR, 95% CI: 1.51, 1.001-2.27; P=0.049) and perfluorohexanesulfonic acid (a long-chain PFAS) (aOR, 95% CI: 1.53, 1.08-2.15; P=0.015) were positively associated with elevated ALT. PFAS levels were lower in bottled water users but higher in current alcohol users. Males and older individuals exhibited higher long-chain PFAS levels, whereas non-water drinkers and current everyday smokers had lower levels of long-chain PFAS.

DISCUSSION

Higher short-chain PFAS mixture levels were linked to elevated ALT, with individual PFAS levels varying by sex and lifestyle factors. Limiting short-chain PFAS exposure may help prevent liver injury.

Toxicokinetics and Perfluorooctanesulfonic Acid-Induced Liver Protein Expression Are Markedly Altered in Mice Lacking Albumin

Perfluorooctanesulfonic acid (PFOS) is a ubiquitous perfluoroalkyl substance (PFAS) linked to liver disease and obesity in humans. Binding studies suggest that albumin is a crucial blood protein influencing PFOS toxicokinetics and hepatotoxicity; however, its role has not been mechanistically tested in vivo. This study used an albumin-deficient mouse model to investigate the relevance of albumin in PFOS tissue distribution and liver disease end points. Adult male C57BL/6J wild-type (Alb+/+) and albumin-deficient (Alb-/-) mice were orally gavaged daily for 7 days with either vehicle or PFOS at 0.5 or 10 mg/kg body weight. The measured PFOS concentrations in plasma were significantly lower in Alb-/- mice compared to those in Alb+/+ mice, while liver concentrations were significantly higher in Alb-/- mice. Binding experiments confirmed these findings, indicating that PFOS toxicokinetics are driven by plasma and tissue binding. Significant changes in liver protein expression did not translate into differences in liver disease end points between genotypes, suggesting the need for chronic exposure studies. Our data imply that disease-related albumin deficiency in humans can influence PFAS toxicokinetics and susceptibility to hepatotoxicity. Our framework using knockout mice can be adapted in future studies to assess the relevance of protein binding and membrane transporters in PFAS distribution and elimination.

Neurotoxic effects of per- and polyfluoroalkyl substances (PFAS) mixture exposure in mice: Accumulations in brain and associated changes of behaviors, metabolome, and transcriptome

Humans are exposed to complex per- and polyfluoroalkyl substances (PFAS) mixtures, yet their neurotoxicity and mechanisms remains unclear. This study exposed male mice to 17 PFAS mixtures at low levels (0.2-20 µg/L) for 49 days via drinking water. Perfluoropentanoic acid (PFPeA), perfluoroheptanoic acid (PFHpA), 6:2 fluorotelomer sulfonic acid (6:2 FTS), and perfluorooctane Sulfonate (PFOS) accumulated in brain tissues, with brain/plasma ratios of 2.03-5.87, 2.94-12.88, 1.90-3.19, and 0.62-0.93, respectively. Electroencephalogram (EEG) results showed significant alterations, including a reduction in beta spectral edge (21.47-13.85 Hz) and an increase in gamma spectral edge (57.64-79.07 Hz). Histopathological analysis revealed necrosis in the hippocampus, contributing to the observed anxiety-like behaviors and memory impairments in exposed mice. Plasma metabolomics highlighted disrupted osmoprotectants, impaired glutamatergic synapse function, and tryptophan metabolism. Brain metabolomics demonstrated suppression of purine metabolism and activation of arachidonic acid metabolism, suggesting involvement in neurotoxic effects. Transcriptomic profiling further identified dysregulation in neuroactive ligand-receptor interactions, cholinergic and GABAergic synapses, and calcium signaling pathways, with oxytocin signaling highlighted as a critical mechanism. This study, for the first time, links PFAS mixture to neurotoxicity via neurotransmitter-related pathways, underscoring the need for public health policies and preventive strategies to mitigate PFAS exposure risks.

Celecoxib as a potential treatment for hepatocellular carcinoma in populations exposed to high PFAS levels

Per- and polyfluoroalkyl substances (PFAS), including perfluorooctane sulfonate and perfluorooctanoic acid, are associated with adverse human effects. However, few studies have assessed the effects of PFAS mixtures on hepatocellular carcinoma (HCC). In this study, we systematically investigated the effects and underlying mechanisms of PFAS mixtures on the proliferation, migration, and invasion of HCC cells (JHH-7 and Li-7) in vitro using a combination of biological techniques and high-coverage untargeted metabolomics. A six day exposure to a 5 μM PFAS mixture significantly enhanced the malignant progression of HCC in vitro. Metabolomic analysis identified the upregulation of prostaglandin E2 (PGE2) as a key factor associated with these effects. This hypothesis was further validated using celecoxib, a PGE2 inhibitor, which reduced PGE2 levels in HCC cells, consequently slowing their migration and invasion. Additionally, mice treated with celecoxib exhibited reduced tumor volumes compared with those treated with PFAS alone. These results suggest that PFAS exposure enhances HCC malignancy through the PI3K/AKT signaling pathway via increased PGE2 production. In conclusion, a 5 μM PFAS mixture accelerates HCC proliferation and invasion; moreover, celecoxib demonstrates potential as a therapeutic agent that inhibits these effects.

An analytical screening platform to differentiate acute and prolonged exposures of per- and polyfluoroalkyl substances on invasive cellular phenotypes

Per- and polyfluoroalkyl substances (PFAS) are "forever chemicals" and pervasive environmental contaminants associated with cancer. Epidemiological studies found that an increased incidence of hormone-sensitive breast cancer is correlated with PFAS exposure. Cell-based assays provide a well-controlled experimental platform to quantify cellular responses as a function of exposure. Given the nearly 15,000 known PFAS on the Environmental Protection Agency's toxicity database (DSSTox), in vitro models are the only feasible approach to screen this large molecular library. One of the hallmarks of cancer is increased migration and invasion, processes that are the gateway to metastasis. Using a paper-based invasion assay developed in our lab, we compared the invasion of the MCF7 and M231 cell lines after acute and prolonged exposures to 2 legacy PFAS compounds, individually and in an equimolar mixture: perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). The acute exposures quantified cellular movement after a 24-h period in the presence of the molecule of interest. The prolonged exposures in this work exposed 5 consecutive cell passages to the PFAS. We hypothesized that prolonged PFAS exposures would select for invasive subpopulations. These prolonged exposures increased the invasion of MCF7 and M231 cells compared to acute exposures of the same PFAS concentration (10 µM). The prolonged exposures to PFOA and PFOS at environmentally relevant concentrations (10 nM) did not increase invasion. Our results highlight the need to assess different exposure durations in vitro and that the paper-based invasion assay is a reasonable screening tool.

Robust titanium suboxide anodes doped by sintering enhance PFOS degradation in water

Per- and Polyfluoroalkyl Substances (PFAS) are a class of persistent organic pollutants that are ubiquitous in the environment, while PFOS is one most representative PFAS of extraordinary persistence. Electrochemical oxidation (EO) is promising for destructive treatment of PFAS in water, and Magnéli phase titanium suboxide (TSO) is regarded as one of only few suitable anode materials for this application. We herein conducted an in-silico survey with Density Functional Theory (DFT) simulations to identify possible beneficial dopant elements, and then prepared TSO anodes doped with Niobium (Nb-TSO) or Cerium (Ce-TSO) by sintering. The doped TSO thus prepared exhibited great robustness, having service lifetimes longer than the pristine Ti4O7 anode, making them useful for EO applications in PFAS treatment. PFOS degradation by EO using Nb-TSO anode was faster than that on the pristine Ti4O7 anode, with energy consumption approximately 1.8 times lower. Further characterizations and DFT simulations reveal that the enhanced efficiency of Nb-TSO anode is attributed to its reduced charge transfer resistance and increased effective electroactive surface area (EESA). The EESA of the Ce-TSO anode was reduced in comparison to the pristine Ti4O7, but PFOS degradation rates normalized by EESA were increased significantly for EO with Ce-TSO anode, due to its increased oxygen evolution potential (OEP) and hydroxyl radical production. The doped TSO anodes prepared in this study by sintering will be useful in EO treatment of PFAS-contaminated waters, with improved service life and performance, and the study provides understandings to guide further improvements of the TSO anodes via doping.

Characterization of POP mixture redistribution and identification of their molecular signature in xenografted fat mice

Persistent organic pollutants (POPs) are associated with many adverse health effects in humans, including cancers, immune, reproductive, neurological disorders and metabolic diseases. These chemicals are known to accumulate in fatty tissues, from which they can be released in other tissue compartments of living organisms, in particular, upon weight loss. This dynamic distribution of POPs remains, however poorly investigated. In this study, a xenografted POP-contaminated adipose tissue (AT) model was used to assess 1) their concentrations in the ATs, the liver and the brain and 2) their associated effects by transcriptomics, metabolomics and lipidomics approaches. In the ATs, the liver and the brain of mice grafted with POP-contaminated fat pad, most of POPs were detected 3 days and 21 days after the graft with the highest concentrations in the ATs and the lowest concentrations in the brain. Conversely, per- and polyfluoroalkyl substances presented a distinct profile as they persist in the liver but not in the ATs or in the brain. In the AT of POP-exposed mice, the most dysregulated pathways were related to mitochondrial functions, endobiotic (carbohydrate, lipid, amino acid) and xenobiotic metabolism and inflammatory response. In the liver of grafted mice, many pathways related to mitochondrial functions and metabolism were dysregulated. These results support that realistic mixture of POPs that accumulate in AT and liver induces a systemic metabolic dysfunction which may represent the mechanisms by which the POPs can promote metabolic diseases such as obesity, type 2 diabetes and cardiovascular diseases.

Associations of Serum Per- and Polyfluoroalkyl Substances with Genotoxic Biomarkers: New Insights from Cross-Sectional and In Vivo Evidence

The effects of perfluoroalkyl and polyfluoroalkyl substances (PFAS) on genomic stability remain unclear. Here, a cross-sectional study was conducted to establish the associations of PFAS with genotoxic biomarkers. We recruited a cohort of 453 residents in 2021 in Zhejiang, China. Thirty PFAS in serum were quantified, alongside seven indicators of genomic stability [five rDNA copy numbers (rDNA-CN), mitochondrial DNA copy numbers (mtDNA-CN), and relative telomere length (RTL)] in whole blood. Results showed that PFUnDA, perfluorohexanesulfonic acid (PFHxS), perfluorooctanesulfonic acid (PFOS), 6:2 Cl-PFESA, and PFO5DoDA were positively correlated with rDNA-CN, while PFHpA, PFOA, and PFMOAA showed inverse associations. PFO4DA and PFO5DoDA were positively correlated with mtDNA-CN. PFOA, HFPO-TA, and PFMOAA were negatively associated with the RTL, while perfluorononanoic acid, PFHxS, PFOS, and 6:2 Cl-PFESA showed positive associations. Nonlinear exposure-response relationships were also observed between PFAS and genotoxic biomarkers using restricted cubic spline models. Furthermore, PFAS mixtures were positively associated with mtDNA-CN, with PFO5DoDA showing the highest contribution by the quantile-based g-computation model. In vivo studies further confirmed that PFO5DoDA increased mtDNA-CN in male mice in a dose-dependent manner. This study provides novel evidence that PFAS disrupt genomic stability, with effects varying by functional groups and fluoroalkyl(ether) chain lengths.

Fisetin Attenuates Zinc Overload-Induced Hepatotoxicity in Mice via Autophagy-Dependent Nrf2 Activation

Zinc (Zn) imbalance-deficiency or overload-is implicated in hepatocyte injury, yet its mechanisms and therapeutic strategies remain incompletely understood. This study investigated Zn dyshomeostasis-induced hepatotoxicity in AML12 hepatocytes and evaluated fisetin's protective potential in diet-induced Zn overload C57BL/6 mice for in vivo validation. In AML12 cells, both Zn deficiency and overload impaired hepatocyte viability and promoted oxidative stress, but only overload activated autophagy and the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. Fisetin, a natural flavonoid with well-documented antioxidant and anti-inflammatory properties, selectively mitigated Zn overload-induced AML12 cytotoxicity and oxidative damage by enhancing autophagic flux and Nrf2 signaling without Zn chelation, while demonstrating no effect on Zn deficiency. Specifically, fisetin required autophagy to sustain Nrf2 activation, as chloroquine abolished its protective effects. In vivo, fisetin administration (200 mg/kg BW, oral gavage) alleviated Zn overload-associated weight loss and hepatic oxidative damage in mice, paralleling its in vitro effects through reinforced autophagy-Nrf2 axis activation. The autophagy-dependent Nrf2 activation mechanism highlights fisetin's therapeutic potential for Zn-related liver disorders.

Design, synthesis, and in-vitro/in-vivo pharmacodynamic studies of novel aza-fused heterocyclic compounds against herpes simplex virus type 1

Herpes simplex virus type 1 (HSV-1) is a prevalent pathogen that can lead to severe diseases, including herpes labialis, keratitis, and encephalitis. The development of novel antiviral therapies is significant due to the limited number of available treatments and the emergence of drug-resistant strains. In this study, a series of aza-fused heterocyclic derivatives were synthesized and evaluated for antiviral efficacy. Compound 5i demonstrated notable antiviral activity in vitro with an EC50 (Effective Concentration 50 %) of 1.95 ± 0.07 μM. This effect was achieved by inhibiting viral replication and targeting viral ICP4 and gD proteins. In addition, the expression of STING and NF-κB signaling pathways was down-regulated, cytokine storm was reduced, and the multi-targeted activity of compound 5i inhibited apoptosis. The high efficacy of compound 5i was demonstrated in a mouse herpes encephalitis model. Infected mice's survival significantly improved, and viral load in brain tissue was substantially reduced in the presence of compound 5i. Furthermore, compound 5i demonstrated favorable safety in preliminary in vivo evaluations, with no adverse effects on major organs observed. In conclusion, the aza-fused heterocyclic derivative 5i has substantial potential as a therapeutic agent for HSV-1 infection, providing a valuable foundation for further drug development and clinical translation.

Association between PFAS exposure and metabolic-related biomarkers in Spanish adolescents

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) exert endocrine disruptive effects on the endocrine-metabolic axis. Emerging knowledge suggests that kisspeptin may play a key role in these effects.

OBJECTIVE

To assess the cross-sectional association of blood PFAS concentrations with kisspeptin levels, KISS1 gene DNA methylation, and metabolic-related biomarkers in adolescent males from the Spanish INMA-Granada cohort.

METHODS

Seven PFAS and twelve biomarkers (glucose-GLU, total cholesterol-TC, triglycerides, LDL, HDL, ALP, AST, ALT, GGT, total bilirubin-BILT, direct bilirubin-BILD, and urea) were measured in plasma and serum, respectively, from 129 adolescent males (15-17 yrs). Systolic and diastolic blood pressure (SBP, DBP), pulse, z-scored body mass index, kisspeptin protein levels (n = 104) and whole blood KISS1 DNA methylation (n = 117) were determined. Linear regression models, weighted quantile sum (WQS), and Bayesian kernel machine (BKMR) were fit.

RESULTS

PFHpA was associated with lower GLU levels [% change per log-unit increase in plasma concentrations (95%CI) = -4.73 (-8.98;-0.28)], and PFUnDA with higher GLU, TC, and HDL levels. In models adjusted by kisspeptin level, PFOS was associated with higher SBP [3.42 (-0.12; 7.09)]. Additionally, PFNA and total PFAS concentrations were associated with higher kisspeptin levels [3.91 (0.55; 7.37) and 6.14 (0.47; 12.13), respectively]. Mixture models showed that combined PFAS exposure was associated with higher HDL, lower hepatic biomarkers (ALT, BILD) and higher kisspeptin levels.

CONCLUSION

Certain PFAS (e.g. PFUnDA) and their mixture were associated with metabolic-related biomarkers, mainly GLU, HDL, and SBP. These associations may be influenced by kisspeptin levels. More studies are needed to verify these observations.

Perfluorooctane sulfonate induced ferritinophagy via detyrosinated alpha tubulin-TRIM21-HERC2-regulated NCOA4 degradation in hepatocytes

The persistent organic pollutant perfluorooctane sulfonate (PFOS) is demonstrated to induce hepatotoxicity through disrupting iron homeostasis and subsequent ferroptosis in hepatocytes. However, it is still elusive in the mechanisms underneath the dysfunctional iron metabolism caused by PFOS. In this study, we observed that PFOS activated the nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy in mice liver and human hepatocytes. PFOS reduced the ubiquitination of NCOA4, subsequently causing an increase in the expression of NCOA4. PFOS induced the ubiquitination of HECT and RLD domain-containing E3 ubiquitin protein ligase 2 (HERC2), an upstream negative regulator of NCOA4, leading to the degradation of HERC2. PFOS upregulated the level of detyrosinated α-tubulin (detyr-α-tubulin) in hepatocytes. Under PFOS exposure, detyr-α-tubulin interacted with tripartite motif containing 21 (TRIM21), another E3 ubiquitin ligase responsible for HERC2 degradation. Despite the reduction in the protein level of HERC2, the increases in detyr-α-tubulin and the interaction between detyr-α-tubulin and TRIM21 caused by PFOS facilitated the interaction between TRIM21 and HERC2. Furthermore, inhibiting α-tubulin detyrosination by parthenolide reversed the ferritinophagy and the following ferroptosis caused by PFOS. Collectively, this study points out the existence of ferritinophagy and enriches the understanding of the alteration in iron metabolism under PFOS exposure, providing novel mechanistic insights into the hepatic toxicity of PFOS.

Legacy, alternative, and precursor PFAS and associations with lipids and liver function biomarkers: results from a cross-sectional analysis of adult females in the MIREC-ENDO study

BACKGROUND

Legacy per- and polyfluoroalkyl substances (PFAS) can promote dyslipidemia; however, evidence is lacking for alternative and precursor PFAS. We investigated associations between serum concentrations of 31 PFAS and concurrently measured lipids and liver function biomarkers.

METHODS

PFAS, lipids, and liver function biomarkers were analyzed in serum samples provided by 282 adult females participating in a 2018-2021 follow-up study of a Canadian pregnancy cohort. We examined percent differences in outcomes continuously for 17 PFAS with >50% detection and as detected vs. not detected for 14 PFAS with 10-50% detection. We also examined associations with the sum of 7 PFAS recommended by the National Academies of Sciences, Engineering, and Medicine guidance report on PFAS testing and 17 PFAS. We used weighted quantile sum (WQS) and quantile g-computation models to estimate joint associations.

RESULTS

Each two-fold increase in concentrations of PFHxS, PFOS, PFNA, PFDA, PFHpS, and Σ7PFAS were associated with up to 7% higher total and LDL cholesterol and the TC:HDL ratio. Individuals with detectable concentrations of N-EtFOSA, N-MeFOSA, PFBS, and 9Cl-PF3ONS had up to 17% higher total and LDL cholesterol and TC:HDL. Each one-quartile increase in the mixture of 7 PFAS was associated with up to 10% higher total and LDL cholesterol. Adding additional PFAS to the mixture (17 PFAS) made estimates less precise in WQS models and attenuated associations to the null in quantile g-computation models.

CONCLUSION

Alternative and precursor PFAS, including replacements for legacy PFAS, are associated with higher cholesterol levels; prospective studies are required to confirm these findings.

Association Between Perfluoroalkyl Substance (PFAS) Exposure and Nonalcoholic Fatty Liver Disease in Korean Adults: Results From the KoNEHS 2018-2020: A Cross-Sectional Study

OBJECTIVES

Nonalcoholic fatty liver disease (NAFLD) is a major public health problem and the most common chronic liver disease today. In Korea, the prevalence and incidence of NAFLD are currently very high, causing a serious social burden. Perfluoroalkyl substances (PFAS) have been consistently implicated as a potential cause of NAFLD, but research in Koreans is limited.

METHODS

Using data from the 4th Korean National Environmental Health Survey (KoNEHS, n = 2859), we investigated the association between PFAS blood levels and NAFLD. Multivariable logistic regression models were used to calculate odds ratios (ORs) for the effects of PFAS. A mediation analysis was also conducted to examine the mediating effect of obesity. Finally, weighted quantile sum (WQS) and G-computation methods were implemented to evaluate the joint effect of PFAS mixtures. Hepatic steatosis index was used as a diagnostic tool for NAFLD.

RESULTS

Through multivariable logistic regression, statistically significant associations with NAFLD were observed for perfluorooctanoic acid (PFOA) (OR 1.09-1.39), perfluorooctansulfonate (PFOS) (1.09-1.40), perfluorohexanesulfonic acid (PFHxS) (1.04-1.22), perfluorononanoic acid (PFNA) (1.12-1.42), and total PFAS (1.21-1.81). We also found that obesity was a significant mediator for PFOA, PFNA, and total PFAS. The ORs for NAFLD obtained by WQS and G-computation methods in the multivariable adjusted model were 1.10-1.46 and 1.08-1.32, respectively.

CONCLUSIONS

This study confirmed a significant association between some PFAS and increased odds of NAFLD. Excessive exposure to PFAS might explain the high prevalence and incidence of chronic liver disease in Koreans. Long-term cohort studies are needed to assess geographic and occupational exposures in the Korean population.

High-Throughput Screening of Polyfluoroalkyl Substances Using Solid-Phase Microextraction Coupled to Microfluidic Open Interface-Mass Spectrometry

Efficient and sustainable methods for large-scale PFAS monitoring are critical for addressing environmental and public health challenges. This work presents a high-throughput sample preparation system capable of processing up to 48 samples simultaneously using solid-phase microextraction (SPME) and was directly coupled with mass spectrometry (MS) via an automated microfluidic open interface (MOI), bypassing the need for chromatographic separation. The SPME-MOI-MS approach achieves sensitive detection of 18 PFAS in drinking water, with limits of detection (LODs) between 1 and 10 pg/mL, using just 1.5 mL of sample and an average analysis time of 2.8 min per sample. The SPME blades, employed to enhance sensitivity in place of standard SPME fibers, incorporate a matrix-compatible coating material that enables effective PFAS screening in water as well as complex matrices including blood, beer, and beef. In addition, significantly low recovery and reproducibility of nonpolar PFAS in water analysis have been found and studied, indicating that using a glass container and adding a small percentage of acetonitrile can address this issue.

Deciphering per- and polyfluoroalkyl substances mode of action: comparative gene expression analysis in human liver spheroids

Understanding the mechanisms by which environmental chemicals cause toxicity is necessary for effective human health risk assessment. High-throughput transcriptomics (HTTr) can be used to inform risk assessment on toxicological mechanisms, hazards, and potencies. We applied HTTr to elucidate the molecular mechanisms by which per- and polyfluoroalkyl substances (PFAS) cause liver perturbations. We contrasted transcriptomic profiles of PFOA, PFBS, PFOS, and PFDS against transcriptomic profiles from established liver-toxic and non-toxic reference compounds, alongside peroxisome proliferator-activated receptors (PPARs) agonists. Our analysis was conducted on metabolically competent 3-D human liver spheroids produced from primary cells from 10 donors. Pathway analysis showed that PFOS and PFDS perturb many of the same pathways as the known liver-toxic compounds in the spheroids, and that the cholesterol biosynthesis pathways are significantly affected by exposure to these compounds. PFOA alters lipid metabolism-related pathways but its expression profile does not closely match reference compounds. PFBS upregulates many degradation-related pathways and targets many of the same pathways as the PPAR agonists and acetaminophen. Our transcriptional analysis does not support the claim that these PFAS are DNA-damaging in this model. A multidimensional scaling (MDS) analysis revealed that PFOS, PFOA, and PFDS cluster together in the same multidimensional space as liver-damaging compounds, whereas PFBS clusters more closely with the non-liver-damaging compounds. Benchmark concentration-response modeling predicts that all the PFAS are bioactive in the liver. Overall, our results show that these PFAS produce unique transcriptional changes but also alter pathways associated with established liver-toxic chemicals in this liver spheroid model.

Perfluorooctanoic acid increases serum cholesterol in a PPARα-dependent manner in female mice

Per- and polyfluoroalkyl substances (PFAS) are a large group of persistent chemicals that are pervasive in the environment leading to widespread exposure for humans. Perfluorooctanoic acid (PFOA), one of the most commonly measured PFAS in people, disrupts liver and serum lipid homeostasis as shown in animal toxicity and human epidemiological studies. We tested the hypothesis that the effects of PFOA exposure in mice expressing mouse PPARα (mPPARα) are driven largely through PPARα-dependent mechanisms while non-PPARα dependent mechanisms will be more apparent in mice expressing human PPARα (hPPARα). Female and male mPPARα, hPPARα, and PPARα null mice were exposed to PFOA (0.5, 1.4 or 6.2 mg PFOA/L) via drinking water for 14 weeks. Concurrently, mice consumed an American diet containing human diet-relevant amounts of fat and cholesterol. Here, we focused on the effects in female mice, given the dearth of data reported on PFAS-induced effects in females. Increasing the duration of PFOA exposure reduced weight gain in all genotypes of female mice while end-of-study body fat was lower in PFOA exposed hPPARα and PPARα null mice. Serum cholesterol, but not triacylglyceride, concentrations were increased by PFOA exposure in a PPARα-dependent manner. Hepatic triacylglycerides were higher in vehicle-exposed mPPARα and PPARα null mice than hPPARα mice, and PFOA significantly reduced concentrations in mPPARα and PPARα null mice only. In contrast, PFOA increased hepatic cholesterol content in a PPARα-dependent manner. Changes in liver and serum cholesterol may be explained by a strong, PPARα-dependent downregulation of Cyp7a1 expression. PFOA significantly increased PPARα target gene expression in mPPARα mice. Other nuclear receptors were examined: CAR target gene expression was only induced by PFOA in hPPARα and PPARα null mice. PXR target gene expression was induced by PFOA in all genotypes. Results were similar in male mice with two exceptions: (1) vehicle-exposed male mice of all genotypes were equally susceptible to diet-induced hepatic steatosis; (2) male mice drank less water, resulting in lower serum PFOA levels, which may explain the less significant changes in lipid endpoints. Overall, our results show that PFOA modifies triacylglyceride and cholesterol homeostasis independently and that PPARα plays an important role in PFOA-induced increases in liver and serum cholesterol.

Per- and polyfluoroalkyl substances exposures are associated with non-alcoholic fatty liver disease, particularly fibrosis

Per- and polyfluoroalkyl substances (PFAS) have been reported to exert hepatotoxic effects; however, their impact on nonalcoholic fatty liver disease (NAFLD) remains unclear. This study aimed to investigate the association between PFAS exposure and NAFLD in Korean adults, thereby contributing to the generalization of PFAS's hepatotoxic effects. Using data from the 2018-2020 Korean National Environmental Health Survey (KoNEHS), we analyzed 2635 Korean adults. PFAS exposure levels were estimated based on the serum concentrations of five PFAS. NAFLD was assessed using two steatosis-related indices (hepatic steatosis index [HSI] and fatty liver index [FLI]) and two fibrosis-related indices (fibrosis-4 index [FIB-4] and aspartate aminotransferase to platelet ratio index [APRI]). The models included these indices as continuous and dichotomous variables, the latter based on diagnostic criteria from previous studies. Associations with PFAS exposure were examined using multiple linear regression and robust Poisson regression models. Positive associations were observed between PFAS exposure and three of the four continuous indices, excluding the FLI, as well as the prevalence of NAFLD diagnosed using these indices. Specifically, the HSI showed a significant association only with perfluorononanoic acid, whereas fibrosis-related indices (FIB-4 and APRI) were significantly associated with all five individual PFAS. The associations were stronger in female and non-obese groups when stratified by sex and obesity status. The results of the Bayesian kernel machine regression analysis evaluating the health effects of PFAS mixtures indicated an association between PFAS mixtures and NAFLD, particularly fibrosis-related indices. Additionally, significant associations with NAFLD indices were mostly observed in females and non-obese groups, supporting the findings from the individual PFAS exposure analyses. Our findings suggest that PFAS are associated with NAFLD, particularly for fibrosis. Considering the high serum PFAS concentrations in the Korean population, continuous monitoring and prospective cohort studies are warranted.

Differential hepatic activation of mouse and human peroxisome proliferator-activated receptor-α by perfluorohexane sulfonate

Exposure of perfluorohexane sulfonate (PFHxS) is associated with hepatomegaly and accumulation of lipids that may be mediated by nuclear receptors like peroxisome proliferator-activated receptor-α (PPARα), constitutive androstane receptor (CAR), or pregnane X receptor (PXR). This study tested the hypotheses that: (i) PFHxS causes changes in liver by activating PPARα, CAR, or PXR, and (ii) there is a species difference in PPARα activity by PFHxS. Wild-type, Ppara-null, and PPARA-humanized mice were fed either a control diet, or one containing 2.2 mg PFHxS/kg diet or 25.8 mg PFHxS/kg diet for either 7 or 28 days, and target gene expression was examined. Relative liver weights were similar after 7 days with either 2.2 or 25.8 mg PFHxS/kg dietary exposure compared with controls. Relative liver weights were higher after treatment for 28 days in all 3 genotypes fed 25.8 mg PFHxS/kg diet compared with controls. The concentration of PFHxS was dose-dependently increased in serum and liver compared with controls. PFHxS exposure of 2.2 and 25.8 mg PFHxS/kg diet caused an increase in expression of PPARα target genes in wild-type mice and this effect was not observed in similarly treated Ppara-null mice or PPARA-humanized mice. Administration of PFHxS caused increased expression of the CAR target gene Cyp2b10 in all 3 genotypes at both timepoints, and the PXR target gene Cyp3a11 in all 3 genotypes after 28 days. Exposure to PFHxS can increase liver weight due in part to the activation of mouse, but not human, PPARα. Activation of CAR and PXR by PFHxS also likely contributes to the observed hepatomegaly in all 3 genotypes.

Assessment of PFAS levels in drinking water: A case study from Poznań County (Poland)

Exposure to per- and polyfluoroalkyl substances (PFAS) through drinking water has emerged as a significant public health concern due to their persistent, bioaccumulative nature and adverse health effects. Drinking water is the primary non-occupational source of PFAS exposure. Recently, investigative journalism has alerted about the presumptive contamination of drinking water at various European sites, including Poland. However, direct data on PFAS concentrations in raw and treated drinking water in Poland remain scarce. Therefore, this study analyzed the concentrations of 20 PFAS in 18 drinking water samples from Poznań County in Greater Poland, where the contamination of drinking water with PFAS was also presumed. In most samples (14/18; 77.7 %), PFAS concentrations were below the method detection limit (<0.001 μg/L). Positive samples revealed total PFAS levels in the 0.0014-0.0041 μg/L range, decisively below the safety threshold established by the European Drinking Water Directive (<0.1 μg/L). Daily consumption of 1.5 or 2.0 L of water containing PFAS by a 70-kg adult would constitute 4.8-9.3 % or 6.4-18.6 % of tolerable intake set by the European Food Safety Authority. These findings suggest that drinking water in the studied area is not a significant source of PFAS exposure. Further research is recommended to assess PFAS contamination in drinking water across a broader geographic scope in Poland to better understand the national contamination status.

Associations between per-and polyfluoroalkyl substances (PFAS) and county-level cancer incidence between 2016 and 2021 and incident cancer burden attributable to PFAS in drinking water in the United States

BACKGROUND

Exposure to per- and polyfluoroalkyl substances (PFAS) has been linked with various cancers. Assessment of PFAS in drinking water and cancers can help inform biomonitoring and prevention efforts.

OBJECTIVE

To screen for incident cancer (2016-2021) and assess associations with PFAS contamination in drinking water in the US.

METHODS

We obtained county-level age-adjusted cancer incidence (2016-2021) from the Surveillance, Epidemiology, and End Results (SEER) Program. Data on PFAS levels in public drinking water systems were obtained from the Third (UCMR3; 2013-2015) and Fifth (UCMR5; 2023-2024) Unregulated Contaminant Monitoring Rule. UCMR3 measured PFOS, PFOA, PFNA, PFHxS, PFHpA, and PFBS. UCMR5 expanded measurements to include PFBA, PFHxA, PFPeA, and PFPeS. We created indicators of PFAS detection and, for UCMR5, concentrations above Maximum Contaminant Levels (MCLs). MCLs for PFOA and PFOS are 4 ng/L, and for PFNA and PFHxS are 10 ng/L. We used Poisson regression models to assess associations between PFAS detection or MCL violation and cancer incidence, adjusting for potential confounders. We estimated the number of attributable cancer cases.

RESULTS

PFAS in drinking water was associated with increased cancer incidence in the digestive, endocrine, oral cavity/pharynx, and respiratory systems. Incidence rate ratios (IRRs) ranged from 1.02 to 1.33. The strongest association was observed between PFBS and oral cavity/pharynx cancers (IRR: 1.33 [1.04, 1.71]). Among males, PFAS was associated with cancers in the urinary, brain, leukemia, and soft tissues. Among females, PFAS was associated with cancers in the thyroid, oral cavity/pharynx, and soft tissue. PFAS in drinking water is estimated to contribute to 4626 [95% CI: 1,377, 8046] incident cancer cases per year based on UCMR3 data and 6864 [95% CI: 991, 12,804] based on UCMR5.

IMPACT STATEMENT

The ecological study examined the associations between PFAS in drinking water measured in two waves (2013-2015 and 2023-2024) and cancer incidence between 2016 and 2021. We found that PFAS in drinking water was associated with cancers in the organ system including the oral cavity/pharynx, lung, digestive system, brain, urinary system, soft tissue, and thyroid. Some cancers have not been widely studied for their associations with PFAS. We also observed sex differences in the associations between PFAS and cancer risks. This is the first ecological study that examined PFAS exposure in drinking water and various cancer risks.

A review of the occurrence and distribution of Per- and polyfluoroalkyl substances (PFAS) in human organs and fetal tissues

This review synthesizes current evidence on PFAS concentrations across human organs and tissues, excluding blood matrices. Literature search was conducted using PubMed, Web of Science, and Scopus. The earliest reported study on the topic measured PFOS, PFOSA, PFOA, and PFHxS levels in human liver and serum, showing mean liver concentrations of 18.8 ng/g and a liver-to-serum ratio of 1.3:1 for PFOS. Subsequent research extended these findings to other organs, with measurements in pooled samples indicating organ-specific accumulation patterns. PFOS was predominant in liver, kidney, and lung, while PFOA was more prominent in bone. Pathological conditions, such as liver disease, have shown to influence PFAS distribution, with diseased tissues exhibiting altered accumulation patterns. On the other hand, the occurrence of PFAS in fetal and placental tissues demonstrated that these compounds cross the placenta, although fetal exposure levels were significantly lower than maternal levels. Tissue-specific accumulation has been reported, with liver and lung showing higher concentrations compared to other fetal tissues. Associations between PFAS levels in the placenta and birth outcomes indicated potential sex-specific effects, including reduced birth weight in male infants exposed to higher PFOS levels. This review highlights important differences in the detection frequencies and concentrations of PFAS across organs and the specific studies. These variations are attributed to differences in analytical methods, sample characteristics, and exposure sources. The findings underscore the need for standardized methodologies and further research to better understand PFAS distribution in human tissues and their potential health impacts, particularly during critical developmental stages.

Exposure to Per- and Polyfluoroalkyl Substances and the Risk of Prostate and Ovarian Cancer: An Epidemiologic Meta-Analysis

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants. Previous research has linked PFAS exposure to prostate and ovarian cancer risk, however, the conclusions have been inconsistent. This research purpose was to determine the relationship between PFAS exposure and prostate and ovarian cancer at the population level.

METHODS

We systematically reviewed three databases-PubMed, Web of Science, and Embase-for research from when these databases were established to April 15, 2024. The quality of the retrieved research was evaluated using the Newcastle-Ottawa Scale (NOS) quality measurement tool. Meta-analysis of the extracted data was conducted using Stata 18. We also conducted sensitivity and subgroup analyses, as well as Begg's and Egger's tests.

RESULTS

Twelve publications were involved in the analysis for prostate cancer, and six were included for ovary cancer. The outcomes indicated that PFOS exposure was positively related to prostate cancer (OR: 1.13, 95% CI: 1.00-1.28), while mixed PFAS exposure was positively related to ovarian cancer (OR: 1.63, 95% CI: 1.49-1.78). The source of heterogeneity identified in the subgroup analysis was primarily attributable to variations in study design. No significant study bias was detected in the analysis.

CONCLUSION

The study demonstrated an association between PFAS exposure and both prostate and ovarian cancers. Further investigation is required to clarify the underlying mechanisms and potential associations.

Rural-Urban Disparities in Hepatocellular Carcinoma Deaths Are Driven by Hepatitis C-Related Hepatocellular Carcinoma

INTRODUCTION

Recent data suggest emerging rural-urban disparities in hepatocellular carcinoma (HCC) burden in the United States. We aimed to assess (i) trends in rural vs urban HCC-related mortality and (ii) differences in underlying chronic liver disease etiologies contributing to HCC-related deaths.

METHODS

We used the National Vital Statistics System to examine crude and age-adjusted HCC death rates overall and by etiology for rural and urban residents from 2005 to 2023. Using the National Cancer Institute Joinpoint Trend Analysis Software, we identified statistically significant changes in annual percentage change (APC) in HCC mortality rates.

RESULTS

Examining mortality rates over time, average APC in HCC deaths was significantly higher in rural residents (crude average annual percentage change [AAPC] 4.64, 95% confidence interval [CI] 4.10, 5.34; age-adjusted AAPC 3.53, 95% CI 3.09, 4.07) compared with urban residents (crude AAPC 2.72, 95% CI 2.43, 3.01; age-adjusted AAPC 1.68, 95% CI 1.28, 2.13). Differences in HCC death rate changes were driven by a significantly greater recent decline in HCC cases from hepatitis C virus (HCV) in urban residents (crude APC -6.69, 95% CI -8.85, -5.30 from 2017 to 2023) compared with rural residents (crude APC -3.31, 95% CI -8.05, 0.73 from 2016 to 2023).

DISCUSSION

Annual increases in HCC deaths have been more pronounced in rural compared with urban populations. Deaths from HCV-related HCC have declined with a geographical disparity that favors urban populations, possibly driven by decreased access to HCV screening or availability of highly effective direct-acting antiviral therapies for rural residents. These findings underscore the need for targeted HCV screening and treatment strategies in rural populations in addition to ongoing strategies to combat alcohol use and metabolic diseases.

Associations of exposure to individual polyfluoroalkyl substances and their mixtures with vitamin D biomarkers in postmenopausal women

The potential impact of polyfluoroalkyl substances (PFAS) on vitamin D status in postmenopausal women remains unexplored. This study examined the effects of individual PFAS and their combined exposures on vitamin D biomarkers among 2114 postmenopausal women utilizing data from the National Health and Nutrition Examination Survey (NHANES) spanning 2003-2018. The serum levels of four PFAS compounds, including perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), and perfluorononanoic acid (PFNA), were assessed alongside the 25-hydroxyvitamin D [25(OH)D] level. Our findings indicated that elevated log-transformed PFAS concentrations were significantly associated with reduced 25(OH)D levels (βPFOS: -15.969, 95 % CI: -19.154, -12.785; βPFOA: -17.288, 95 % CI: -22.446, -12.131; βPFNA: -8.510, 95 % CI: -12.148, -4.871; βPFHxS: -4.056, 95 % CI: -7.003, -1.110) and increased odds of vitamin D deficiency (ORPFOS: 2.495, 95 % CI: 1.685, 3.694; ORPFOA: 3.146, 95 % CI: 1.823, 5.429; ORPFNA: 1.906, 95 % CI: 1.357, 2.677; ORPFHxS: 1.480, 95 % CI: 1.109, 1.976). These associations were modified by race, the family incomepoverty ratio and the survey cycle. Notably, non-Hispanic White individuals presented a stronger inverse association between PFOS exposure and 25(OH)D levels. Bayesian kernel machine regression and weighted quantile sum analyses demonstrated that the effects of exposure to mixtures of the four studied PFAS were consistent with the effects of exposure to individual PFAS. These findings indicate that exposure to individual PFAS, particularly PFOA and PFOS, and their four mixtures may adversely affect serum 25(OH)D concentrations in postmenopausal women, underscoring the need for further investigation into the potential impact of PFAS on vitamin D status in this population.

Per- and polyfluoroalkyl substances (PFAS) exposure in the U.S. population: NHANES 1999-March 2020

Per- and polyfluoroalkyl substances (PFAS), also known as "forever chemicals" because of their persistence in the environment, have been used in many commercial applications since the 1940s. Of late, the detection of PFAS in drinking water throughout the United States has raised public and scientific concerns. To understand PFAS exposure trends in the general U.S. population, we analyzed select PFAS serum concentration data from participants ≥12 years old of nine National Health and Nutrition Examination Survey (NHANES) cycles. Our goals were to a) evaluate concentration changes of four legacy PFAS-perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) from 1999 to 2000 to 2017-March 2020, b) discuss serum concentrations and assess demographic predictors of two PFAS measured for the first time in 2017-2018, perfluoro-1-heptanesulfonic acid (PFHpS) and 9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (9CLPF), and c) compare concentration profiles of legacy PFAS in NHANES to profiles in exposed communities. We report a decrease in geometric mean concentrations of the four legacy PFAS (16%-87%, depending on the PFAS) from 1999 to 2000, although in 2017-March 2020, more than 96% of people aged 12-19 years, some of whom were born after PFAS production changes started in the early 2000s, had measurable concentrations of these PFAS. An estimated 78% of the U.S. general population had detectable concentrations of PFHpS, and 8% had detectable concentrations of 9CLPF (>44% of whom self-identified as Asian). Comparing profiles in NHANES and people living in communities with PFAS contamination can help identify exposure sources and evaluate and monitor exposures in select areas or among specific population groups. Collectively, our findings highlight the usefulness of NHANES data to help researchers, public health officials, and policy makers prioritize investigations, monitor exposure changes, and evaluate effectiveness of efforts to limit exposures.

Environmental Pollutants, Occupational Exposures, and Liver Disease

Environmental pollutants significantly impact liver disease development, progression, and outcomes. This review examines the complex relationship between environmental exposures and liver pathology, from malignant conditions like hepatocellular carcinoma to steatotic and cholestatic liver diseases. Key environmental factors include air pollutants, volatile organic compounds, persistent organic pollutants, heavy metals, and per- and polyfluoroalkyl substances. These compounds can act through multiple mechanisms, including endocrine disruption, metabolic perturbation, oxidative stress, and direct hepatotoxicity. The impact of these exposures is often modified by factors such as sex, diet, and genetic predisposition. Recent research has revealed that even low-level exposures to certain chemicals can significantly affect liver health, particularly when combined with other risk factors. The emergence of exposomics as a research tool promises to enhance our understanding of how environmental factors influence liver disease. Importantly, exposure effects can vary by demographic and socioeconomic factors, highlighting environmental justice concerns. Implementation of this knowledge in clinical practice requires new diagnostic approaches, healthcare system adaptations, and increased awareness among medical professionals. In conclusion, this review provides a comprehensive examination of current evidence linking environmental exposures to liver disease and discusses implications for clinical practice and public health policy.

Per- and poly-fluoroalkyl substances (PFAS) in circulation in a Canadian population: their association with serum-liver enzyme biomarkers and piloting a novel method to reduce serum-PFAS

Extensive use of per- and polyfluoroalkyl substances (PFAS) has resulted in their ubiquitous presence in human blood. PFAS exposures have been associated with multiple adverse human health effects. Biomonitoring studies have focused on long-chain PFASs, but these are being replaced by short-chain PFASs or with alternate PFAS chemistries (or replacement chemistries such as GenX), resulting in changes in human exposures with time. Here, we take advantage of serum samples collected as part of a clinical trial testing the efficacy of a dietary fiber intervention to reduce serum cholesterol to investigate exposure to PFASs in Canadian participants. Serum samples were collected from 72 participants (adult males with elevated cholesterol) in 2019-2020 at baseline and after 4 weeks of the intervention and were analyzed for 17 PFASs. The highest geometric mean serum concentrations of PFAS measured at baseline corresponded to PFOSA (7.1 ng/ml), PFOS (4.2, ng/ml), PFOA (1.8 ng/ml) and PFHxS (1.3 ng/ml). Four long-chain PFASs (PFOA, PFOS, PFOSA and PFHxS) and two short-chain PFASs (PFBA, PFHxA) were detected in 100% of participants. GenX was detected in 71% of participants. Analyses of associations between serum-PFAS concentrations and biomarkers of adverse health outcomes showed the PFBA, PFHxA, PFDA and PFOSA were associated with higher serum gamma-glutamyl transferase concentrations but not with measures of serum-total or low-density lipoprotein cholesterol. Comparison of PFAS concentrations at baseline and after a 4-week follow-up showed that the total PFAS detected decreased in both the control and cholesterol intervention groups. However, the suite of long-chain PFASs of concern identified by the United States National Academies of Sciences, Engineering, and Medicine, significantly decreased only in the cholesterol intervention group. This observation suggests that a sustained dietary fiber intervention may reduce long-chain PFAS body burden, but future intervention studies need to control for PFAS exposure sources and extend the dietary supplement intake beyond 4 weeks. Overall, the results show that exposures to short-chain and replacement chemistry PFASs are common in this Canadian population.

Effects of mixed exposure to PFAS on adolescent non-alcoholic fatty liver disease: Integrating evidence from human cohorts, toxicogenomics, and animal models to uncover mechanisms and potential target sites

Extensive evidence suggests a correlation between environmental pollutants, specifically perfluoroalkyl and polyfluoroalkyl substances (PFAS) and non-alcoholic fatty liver disease (NAFLD). This study aims to investigate the association and underlying mechanisms of PFAS-induced NAFLD in adolescents by employing a comprehensive approach of population-based studies, toxicogenomics, and animal models. A total of 2014 freshmen from Dali University were recruited for this study, with 1694 participants undergoing serum testing for PFAS exposure. Additionally, Comparative Toxicogenomics Database analysis and PFAS exposure experiments were conducted by orally administering PFAS to 8-week-old adult C57/6 J mice for 28 days. Epidemiological analysis of the adolescent cohort revealed that perfluorohexanesulfonic acid and perfluorooctanoic acid are significant risk factors for NAFLD in adolescents. Toxicogenomic analysis revealed that the negative regulation of gap junction assembly and glutathione derivative biosynthesis contributes to NAFLD development. Animal model studies further demonstrated that combined PFAS exposure led to pathological changes in hepatocytes, including inflammation and steatosis, elevated liver enzymes, cholestasis, and bile canalicular blockage. This study reveals that PFAS exposure serves as a significant risk factor for hepatic steatosis/NAFLD in adolescents. The activation of cytochrome P4502E1 and glutathione S-transferase A1 signaling highlights new molecular targets for PFAS-induced disruptions in hepatic lipid metabolism.

Integrated Spheroid-to-Population Framework for Evaluating PFHpA-Associated Metabolic Dysfunction and Steatotic Liver Disease

The rising prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD), particularly among pediatric populations, requires identification of modifiable risk factors to control disease progression. Per- and polyfluoroalkyl substances (PFAS) have emerged as potential contributors to liver damage; however, their role in the etiology of MASLD remains underexplored. This study aimed to bridge the gap between human epidemiological data and in vitro experimental findings to elucidate the effect of perfluoroheptanoic acid (PFHpA), a short chain, unregulated PFAS congener on MASLD development. Our analysis of the Teen-LABS cohort, a national multi-site study on obese adolescents undergoing bariatric surgery, revealed that doubling of PFHpA plasma levels was associated with an 80% increase in MASLD risk (OR, 1.8; 95% CI: 1.3-2.5) based on liver biospies. To further investigate the underlying mechanisms, we used 3D human liver spheroids and single-cell transcriptomics to assess the effect of PFHpA on hepatic metabolism. Integrative analysis identified dysregulation of common pathways in both human and spheroid models, particularly those involved in innate immunity, inflammation, and lipid metabolism. We applied the latent unknown clustering with integrated data (LUCID) model to assess associations between PFHpA exposure, multiomic signatures, and MASLD risk. Our results identified a proteome profile with significantly higher odds of MASLD (OR = 7.1), whereas a distinct metabolome profile was associated with lower odds (OR = 0.51), highlighting the critical role of protein dysregulation in disease pathogenesis. A translational framework was applied to uncover the molecular mechanisms of PFAS-induced MASLD in a cohort of obese adolescents. Identifying key molecular mechanisms for PFAS-induced MASLD can guide the development of targeted prevention and treatment.

Extracellular Vesicle (EV) Mechanisms of Toxicity for Per and Polyfluoroalkyl Substances: Comparing Transcriptomic Points of Departure Across Global Versus EV Regulatory Gene Sets

Extracellular vesicles (EVs) are emitted from cells throughout the body and serve as signaling molecules that mediate disease development. Emerging evidence suggests that per- and polyfluoroalkyl substances (PFAS) impact EV release and content, influencing liver toxicity. Still, the upstream regulators of EV changes affected by PFAS exposure remain unclear. This study evaluated the hypothesis that PFAS exposures, individually and in a mixture, alter the expression of genes involved in EV regulation at concentrations comparable to genes involved in global biological response mechanisms. HepG2 liver cells were treated at multiple concentrations with individual PFOS, PFOA, or PFHxA, in addition to an equimolar PFAS mixture. Gene expression data were analyzed using three pipelines for concentration-response modeling, with results compared against empirically derived datasets. Final benchmark concentration (BMC) modeling was conducted via Laplace model averaging in BMDExpress (v3). BMCs were derived at an individual gene level and across different gene sets, including Gene Ontology (GO) annotations as well as a custom EV regulation gene set. To determine relative PFAS contributions to the evaluated mixture, relative potency factors were calculated across resulting BMCs using PFOS as a standard reference chemical. Results demonstrated that PFAS exposures altered the expression of genes involved in EV regulation, particularly for genes overlapping with endoplasmic reticulum stress. EV regulatory gene changes occurred at similar BMCs as global gene set alterations, supporting concurrent regulation and the role of EVs in PFAS toxicology. This application of transcriptomics-based BMC modeling further validates its utility in capturing both established and novel pathways of toxicity.

A Rapid Quantitative Assessment Method for Liver Damage Effects of Compounds Based on Zebrafish Liver Partition Area Ratio

Total liver area is a traditional indicator in evaluating compound liver damage with zebrafish models. However, in some experiments, compounds changed zebrafish liver morphology but total liver area showed no significant difference, indicating it is inaccurate for evaluating compound effects on zebrafish liver damage. Therefore, in this study, transgenic zebrafish Tg(l-fabp:EGFP) labeled with liver cells using green fluorescent protein was used to evaluate compound effects on liver by the liver partition area ratio. The coefficient of variation of the total liver area and the liver partition area ratio of normal zebrafish at different development stages was calculated to determine the precision and dispersion of the liver partition area ratio. Three known hepatotoxic compounds (water extract of psoralea, alcohol, and α-naphthalene isothiocyanate) were used to treat zebrafish, and liver partition area ratio was calculated and verified by liver tissue pathological sections. The Pearson correlation coefficient was used to analyze the correlation between the liver partition area ratio, total liver area, and alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Results showed significant difference in liver partition area ratio between hepatotoxic compound treated group and control group, and it could accurately reflect liver morphology changes. There was a strong correlation between liver partition area ratio and ALT and AST level, whereas that between total liver area and ALT and AST level was low. Therefore, the change in zebrafish liver partition area ratio can be an evaluation indicator for rapid assessment of compound effects on zebrafish liver function damage, more sensitive and accurate than total liver area.

Transcriptome-based analysis reveals the toxic effects of perfluorononanoic acid by affecting the development of the cardiovascular system and lipid metabolism in zebrafish

Perfluorononanoic acid (PFNA) is a perfluoroalkyl acid containing nine carbon chains, with an additional carbon‑fluorine bond that makes it more stable and toxic. Studies have shown that PFNA can harm the reproductive, immune, and nervous systems, as well as many organs, which can increase the risk of cancer. In this study, zebrafish embryos were treated with 0 and 100 μM PFNA for 72 and 96 hpf, and their angiogenesis and haematopoiesis were observed under laser confocal microscopy using Tg (fli1:EGFP) and Tg (gata1:DsRed) transgenic zebrafish. The data showed that PFNA exposure decreased heart rate and slowed blood flow in zebrafish. PFNA was found to inhibit erythropoiesis by O-dianisidine staining. RNA-seq analysis was used to compare gene expression changes in zebrafish from control and 100 μM PFNA-exposed groups at 72 hpf. KEGG results showed significant enrichment of PPAR signaling pathway, fatty acid metabolism, steroid biosynthesis and apoptosis. The RNA-seq results were validated by real-time fluorescence quantitative PCR (RT-qPCR). Oil red O staining and Filipin staining showed increased lipid accumulation after PFNA exposure, and TUNEL staining showed that PFNA exposure led to apoptosis. In conclusion, exposure to PFNA may cause toxic effects in zebrafish by affecting cardiovascular development, causing lipid accumulation and promoting apoptosis.

Role of hepatocyte-specific FOXO1 in hepatic glucolipid metabolic disorders induced by perfluorooctane sulfonate

Perfluorooctane sulfonate (PFOS), a prevalent perfluoroalkyl substance (PFAS), is widely present in various environmental media, animals, and even human bodies. It primarily accumulates in the liver, contributing to the disruption of hepatic metabolic homeostasis. However, the precise mechanism underlying PFOS-induced hepatic glucolipid metabolic disorders remains elusive. The transcription factor forkhead box protein O 1 (FOXO1) plays a crucial role in regulating hepatic glucolipid metabolism; however, its involvement in PFOS-induced hepatic glucolipid metabolic disorders has not been thoroughly explored. Molecular docking revealed high binding affinity between PFOS and FOXO1. Male C57BL/6 mice were exposed to PFOS at doses of 0.3, 1.0, and 3.0 mg/kg body weight for 12 weeks to assess its subchronic effects on hepatic glucolipid metabolism in this work. The results indicate that PFOS exposure increases hepatic acetylated FOXO1 expression, promotes liver lipid accumulation, suppresses gluconeogenesis, whereas fasting blood glucose levels remain unaffected but this dysregulation results in insulin resistance. Furthermore, hepatic deletion of FOXO1 in PFOS-exposed mice ameliorates liver injury and reduces lipid accumulation by suppressing hepatic autophagy without significantly affecting gluconeogenesis. In conclusion, FOXO1 may play a pivotal role in the development of PFOS-induced hepatic glucolipid metabolic disorder.

Insights into toxicological mechanisms of per-/polyfluoroalkyl substances by using omics-centered approaches

The extensive presence of per-/polyfluoroalkyl substances (PFASs) in the environment and their adverse effects on organisms have garnered increasing concern. With the shift of industrial development from legacy to emerging PFASs, expanding the understanding of molecular responses to legacy and emerging PFASs is essential to accurately assess their risks to organisms. Compared with traditional toxicological approaches, omics technologies including transcriptomics, proteomics, metabolomics/lipidomics, and microbiomics allow comprehensive analysis of the molecular changes that occur in organisms after PFAS exposure. This paper comprehensively reviews the insights of omics approaches, especially the multi-omics approach, on the toxic mechanisms of both legacy and emerging PFASs in recent five years, focusing on hepatotoxicity, developmental toxicity, immunotoxicity, reproductive toxicity, neurotoxicity, and the endocrine-disrupting effect. PFASs exert various toxic effects via lipid and amino acid metabolism disruption, perturbations in several cell signal pathways, and binding to nuclear receptors. Notably, integrating multi-omics offers a thorough insight into the mechanisms of toxicity associated with PFASs. The gut microbiota plays an essential regulatory role in the toxic mechanisms of PFAS-induced hepatotoxicity. Finally, further research directions for PFAS toxicology based on omics technologies are prospected.

Unraveling Human Hepatocellular Responses to PFAS and Aqueous Film-Forming Foams (AFFFs) for Molecular Hazard Prioritization and In Vivo Translation

Aqueous film-forming foams (AFFFs) are complex product mixtures that often contain per- and polyfluorinated alkyl substances (PFAS) to enhance fire suppression and protect firefighters. However, PFAS have been associated with a range of adverse health effects (e.g., liver and thyroid disease and cancer), and innovative approach methods to better understand their toxicity potential and identify safer alternatives are needed. In this study, we investigated a set of 30 substances (e.g., AFFF, PFAS, and clinical drugs) using differentiated cultures of human hepatocytes (HepaRG, 2D), high-throughput transcriptomics, deep learning of cell morphology images, and liver enzyme leakage assays with benchmark dose analysis to (1) predict the potency ranges for human liver injury, (2) delineate gene- and pathway-level transcriptomic points-of-departure for molecular hazard characterization and prioritization, (3) characterize human hepatocellular response similarities to inform regulatory read-across efforts, and (4) introduce an innovative approach to translate mechanistic hepatocellular response data to predict the potency ranges for PFAS-induced hepatomegaly in vivo. Collectively, these data fill important mechanistic knowledge gaps with PFAS/AFFF and represent a scalable platform to address the thousands of PFAS in commerce for greener chemistries and next-generation risk assessments.

Mass Spectrometry-Based Spatial Multiomics Revealed Bioaccumulation Preference and Region-Specific Responses of PFOS in Mice Cardiac Tissue

The distribution and bioaccumulation of environmental pollutants are essential to understanding their toxicological mechanism. However, achieving spatial resolution at the subtissue level is still challenging. Perfluorooctanesulfonate (PFOS) is a persistent environmental pollutant with widespread occurrence. The bioaccumulation behavior of PFOS is complicated by its dual affinity for phospholipids and protein albumin. It is intriguing to visualize the distribution preference of PFOS and investigate the differential microenvironment responses at a subtissue level. Herein, we developed a mass-spectrometry (MS)-based spatial multiomics workflow, integrating matrix-assisted laser desorption/ionization MS imaging, laser microdissection, and liquid chromatography MS analysis. This integrated workflow elucidates the spatial distribution of PFOS in mouse cardiac tissue, highlighting its preferential accumulation in the pericardium over the myocardium. This distribution pattern results in greater toxicity to the pericardium, significantly altering cardiolipin levels and disrupting energy metabolism and lipid transport pathways. Our integrated approach provides novel insights into the bioaccumulation behavior of PFOS and demonstrates significant potential for revealing complex molecular mechanisms underlying the health impacts of environmental pollutants.

Comparative study on gene expression profiles in the liver of male neonatal mice prenatally exposed to PFOA and its alternative HFPO-DA

Hexafluoropropylene oxide dimer acid (HFPO-DA), which belongs to the class of perfluoroalkyl ether carboxylic acid (PFECA), is a new alternative to perfluorooctanoic acid (PFOA). However, whether HFPO-DA is a safer alternative to PFOA in neonates remains unclear. In this study, we evaluated neonatal hepatic toxicity on postnatal days 9-10 by orally exposing pregnant CD-1 mice to 0.3 or 3.0 mg/kg/day (low or high doses) of HFPO-DA or PFOA from gestation days 15-17. The results showed that exposure of pregnant mice to HFPO-DA and PFOA induced similar phenotypic effects, including significant decreases in neonatal body weight (BW) and significant increases in liver weight relative to BW in the high-dose. Notably, HFPO-DA exposure significantly decreased in neonatal BW in the low-dose group, whereas PFOA did not. Comprehensive gene expression analysis revealed significant alterations in 408 and 1402 differentially expressed genes (DEGs) in the liver of neonates from the low- and high-dose HFPO-DA groups, respectively, while PFOA significantly altered 0 and 292 DEGs in the corresponding groups. Gene set enrichment analysis indicated that the DEGs induced by HFPO-DA and PFOA were enriched in pathway related to "PPAR signaling", "fatty acid metabolism", and "biological oxidations". In addition, transactivation assays revealed that mouse (m)PPARα and mPPARγ activity of HFPO-DA exceeds that of PFOA and molecular docking simulations analysis predicted that the binding conformation differ between PFOA and HFPO-DA. Overall, our findings demonstrate that HFPO-DA consistently affected neonatal phenotypes, liver gene expression and the molecular initiating events involving PPARα/γ, at lower concentrations than PFOA.

Per- and Polyfluoroalkyl Substances and Female Health Concern: Gender-based Accumulation Differences, Adverse Outcomes, and Mechanisms

The deleterious health implications of perfluoroalkyl and polyfluoroalkyl substances (PFAS) are widely recognized. Females, in contrast to males, exhibit unique pathways for PFAS exposure and excretion, leading to complex health outcomes. The health status of females is largely influenced by hormone-related processes. PFAS have been reported to be associated with various aspects of female health, including reproductive system disorders and pregnancy-related diseases. In this article, we provide insights into the correlations between PFAS and female-prevalent diseases. Current epidemiological and toxicological evidence has demonstrated that the adverse effects of PFAS on the health of the female reproductive system are primarily attributed to the disruption of the hypothalamic-pituitary-gonadal (HPG) axis and hormonal homeostasis. However, these findings do not sufficiently elucidate the intricate associations between PFAS and specific diseases. Furthermore, autoimmune disorders, another category that is more prevalent in women compared to men, require additional investigation. Immune biomarkers pertinent to autoimmune disorders have been observed to be influenced by PFAS exposure, although epidemiological evidence is insufficient to substantiate these relations. Further thorough exploration encompassing epidemiological and toxicological studies is essential to elucidating the inherent influence of PFAS on human pathologies. Additionally, comprehensive investigations into female health issues beyond their reproductive functions is essential.

Arginine Metabolism Reprogramming in Perfluorooctanoic Acid (PFOA)-Induced Liver Injury

Perfluorooctanoic acid (PFOA) is a persistent pollutant that has gained worldwide attention, owing to its widespread presence in the environment. Previous studies have reported that PFOA upregulates lipid metabolism and is associated with liver injury in humans. However, when the fatty acid degradation pathway is activated, lipid accumulation still occurs, suggesting the presence of unknown pathways and mechanisms that remain to be elucidated. In this study, adult C57BL/6N mice were exposed to PFOA at 0.1, 1, and 10 mg/kg/day. Using integrated metabolomics and transcriptomics, it was uncovered that arginine metabolism was differentially downregulated in all three groups. In vitro studies confirmed the downregulation of arginine metabolism in MIHA cell lines treated with PFOA. Supplementation of arginine could effectively rescue liver injury and downregulate the chemokine levels caused by PFOA. This finding highlights the contribution of arginine metabolism in maintaining liver health following PFOA exposure and suggests potential mechanisms of metabolic and immune modulation.

Perfluorooctanoic Acid Induces Ferroptosis in Hepatocytes via Oxidative Stress and AKT/GSK3β/β-Catenin Pathway Disruption

Perfluorooctanoic acid (PFOA), a typical environmental contaminant, has been observed in tissue samples of various diseases, including liver cancer. PFOA can lead to hepatotoxicity, but the underlying molecular mechanism remains unclear. Our results showed that PFOA significantly inhibited HL-7702 (L02) and MIHA cell viability in a time- and dose-dependent manner. Furthermore, PFOA could cause oxidative stress, mitochondrial injury, and ferroptosis. In addition, PFOA upregulated the levels of malondialdehyde and glutathione/oxidized glutathione and downregulated the expressions of SLC7A11 and GPX4, which refer to typical phenotypes of ferroptosis. PFOA suppressed phosphorylation of signaling cascades AKT/GSK3β/β-catenin, indicating the signal pathway might be related to ferroptosis. In order to prove the above hypothesis, the Wnt signaling pathway activator chir99021 was used and the result revealed that PFOA-induced inhibition of p-AKT and its downstream effectors p-GSK3β, SLC7A11, and GPX4 was counteracted. On the other hand, the inhibitor of p-AKT, Ly294002, strengthened PFOA's regulatory actions on these factors. Overall, our results suggest that PFOA can lead to liver cell injury by inducing oxidative stress and ferroptosis. The effects are conferred through the regulation of the AKT/GSK3β/β-catenin signaling cascades.

Per- and Polyfluoroalkyl Substances in Semen Associated with Repeated Measures of Semen Quality in Healthy Adult Men

Although epidemiological studies have explored the association between poly- and perfluoroalkyl substances (PFAS) concentrations and semen quality, existing findings are often inconsistent. Our work aimed to explore the association of PFAS in plasma and semen with repeated measures of semen quality parameters in healthy adults. Plasma was collected at the initial recruitment and semen was collected at least once within five predetermined intervals during an approximately 3-month period. Semen volume, concentration, motility, and total sperm count were measured in each semen specimen. PFAS was measured in individual plasma samples (n = 1252) and pooled semen samples (n = 1019) from multiple collections (or in a single semen sample if no multiple collection was available). The results reveal seminal perfluorooctanoic acid, perfluorooctanesulfonic acid, perfluorohexanesulfonic acid, and 6:2 chlorinated polyfluoroalkyl ether sulfonate were significantly associated with decreased sperm progressive motility and total motility, while multiple seminal PFAS were positively associated with sperm concentration and total sperm count. By contrast, null associations were observed between plasma PFAS and semen quality. Our study provides epidemiological evidence that PFAS exposure may affect male fertility and seminal PFAS should be measured for precise assessment of the impact of PFAS on male reproductive performances.