Associations between PFOA, PFOS and changes in the expression of genes involved in cholesterol metabolism in humans

Prenatal per- and polyfluoroalkyl substance mixtures and weight for length from birth to 12 months: The New Hampshire Birth Cohort Study

OBJECTIVE

To examine the joint associations of plasma concentrations of prenatal per- and polyfluoroalkyl substances (PFAS) mixtures with birth size and postnatal anthropometry measures.

MATERIAL AND METHODS

The current study included 641 mother-child dyads from the New Hampshire Birth Cohort Study. PFAS concentrations were quantified in maternal plasma samples collected during pregnancy (median: 28 weeks of gestation). Information on infant weight and length were abstracted from medical records and converted to sex- and age-standardized weight-for-length z-score according to the World Health Organization standard curves. Bayesian kernel machine regression (BKMR) was used to investigate the joint associations of multiple PFAS concentrations during pregnancy with weight-for-length z score at birth, 6-months, and 12-months. To account for longitudinal outcomes, we also fit linear mixed effect models between PFAS exposure burden score, a novel method to quantify total exposure burden to PFAS mixtures, and changes in weight-for-length from birth to 12 months of age. A multiplicative interaction term ("PFAS burden score × time [birth as a reference, 6 months, and 12 months of age]") was included to evaluate a potential time-varying relationship. All models were adjusted for maternal age, education, marital status, parity, smoking, seafood consumption, pre-pregnancy body mass index, and gestational week of blood draw.

RESULTS

In BKMR models, all 95 % credible intervals included the null value. In linear mixed effects models, PFAS exposure burden score was associated with a lower weight-for-length z-score (β = -0.20; 95 % confidence interval = -0.35, -0.04). The multiplicative interaction term was significant at both 6 and 12 months of age (P < 0.01 for both time points), particularly among female infants, suggesting a shift toward positive associations between the prenatal PFAS mixtures and weight-for-length z-score during infancy.

CONCLUSIONS

Prenatal PFAS mixtures may affect fetal and infant anthropometry measures differently by life stage and biological sex.

Integrated PBPK Modelling for PFOA Exposure and Risk Assessment

Per- and polyfluoroalkyl substances (PFASs) pose significant public health concerns due to their environmental persistence, bioaccumulation, and ubiquitous presence in human biomonitoring (HBM) data, despite regulatory restrictions. This study establishes a deterministic pharmacokinetic model for perfluorooctanoic acid (PFOA), enabling the estimation of PFOA concentrations in major human organs, even at low doses. The model integrates accumulation and recirculation mechanisms of PFOA in hepatic and renal tissues, leveraging publicly available HBM datasets (e.g., HBM4EU, NHANES, literature) to reconstruct bodyweight-normalized intake levels. Importantly, due to the extremely low urinary excretion concentrations of PFOA, most datasets were derived from blood-based measurements, particularly serum while confirming urine as unreliable biomarker of exposure. The analysis underscores the effectiveness of regulatory efforts in reducing PFOA exposures, as evidenced by declining time-trends in estimated exposure levels in recent studies. Risk characterization ratios were calculated based on recommended limits set by the European Food Safety Authority (EFSA), the United States, and Australia. While EFSA's tolerable weekly intake (TWI) indicated a high risk, other regulatory limits suggested less concern about risk at these intake levels. These findings highlight the need for continuous re-evaluation of exposures and targeted studies to identify key determinants of PFOA exposure, informing future regulatory measures. The study emphasizes the critical role of physiologically based pharmacokinetic (PBPK) modeling, HBM data, and exposure reconstruction in advancing chemical risk assessment. These tools form a science-based framework integral to the Chemical Strategy for Sustainability (CSS), enabling accurate predictions of internal exposure levels, empirical validation of models, and robust assessments of real-world exposure scenarios. The integration of these approaches supports the CSS goals of minimizing chemical risks while promoting innovation, ultimately contributing to a sustainable and protective regulatory landscape for human health and the environment.

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.

Longitudinal association of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) exposure with lipid traits, in a healthy unselected population

BACKGROUND

Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic Acid (PFOS) are synthetic substances with long half-lives. Their presence is widespread and pervasive, and they are noted for their environmental persistence. Research has shown these chemicals to be associated with dyslipidaemia, although few studies have considered the long-term associations in the general population.

OBJECTIVES

The aim of this study was to consider the longitudinal and cross-sectional associations with lipid phenotypes.

METHODS

We investigated the association of these chemicals with total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides (TG), and the total cholesterol: high-density lipoprotein ratio (TC:HDL), in a healthy unselected British population of twins (n = 2069), measured at three timepoints between 1996 and 2014.

RESULTS

Serum levels of PFOA and PFOS decreased over time during this period. We demonstrate longitudinal associations across serum levels of both PFOA and PFOS, finding positive associations with TC (PFOA:β = 0.51, p = 1.9e-07; PFOS:β = 0.24, p = 3.8e-05) and LDL (PFOA:β = 0.61, p = 1.7e-11; PFOS:β = 0.42, p = 1.6e-14), and consistent negative associations with HDL and PFOA (β = -0.12, p = 0.003) and PFOS (β = -0.25, p = <2e-16). We also observe cross-sectional associations of PFAS with lipids across all three timepoints.

IMPACT

PFAS remain persistent in the environment, despite regulations, due to their structural properties, leaving humans open to exposure. There is less understanding of how chronic low exposure to these chemicals, particularly within an unselected population, may impact health outcomes. This study reports the longitudinal associations of PFOA and PFOS over an 18-year window with 5 lipid phenotypes, highlighting that despite falling serum levels, PFAS exposure may lead to hyperlipidaemia. We further investigate the cross-sectional associations across three timepoints to understand time-dependent effects, demonstrating associations persist. This work aids our understanding on the long-term effect of chronic PFAS exposure.

Associations between prenatal exposure to PFAS and cardiometabolic health in preadolescents

INTRODUCTION

While a number of studies have examined the effects of prenatal exposure to per- and polyfluoroalkyl substances (PFAS) on childhood obesity, the results reported have been inconsistent and few studies have integrated biological markers. The aim of this study was to investigate the associations between prenatal exposure to PFAS and cardiometabolic health parameters at age 12, taking pubertal stage into consideration.

METHOD

This study included 394 mother-child pairs enrolled in the PELAGIE mother-child cohort (France). Nine PFAS were measured in umbilical cord blood, and the children attended a clinical examination at age 12. Anthropometry, blood metabolic markers, and blood pressure were measured and used to build an internal cardiometabolic score. Linear regression and Quantile G-computation models were used to evaluate individual and mixture PFAS effects, adjusting for confounders and stratifying by sex and pubertal stage.

RESULTS

No statistically significant association was observed between prenatal exposure to PFAS and cardiometabolic score at age 12. In post-menarche girls, perfluorohexane sulfonate (PFHxS) and perfluorodecanoic acid (PFDA) were statistically significantly associated with a decrease in a number of adiposity parameters (e.g., Body mass index z-score: beta [95%CI] = -0.37 [-0.67; -0.07]), as well as a decrease in low-density lipoproteins (LDL) and leptin levels. Similar results were observed with PFAS mixture, with statistically significantly decreased tricipital skinfolds (beta [95%CI] = -1.30 [(-2.54;-0.06)]). Isolated associations, including higher systolic blood pressure, changes in cholesterol levels, and lower adiponectin levels were observed in specific subgroups.

CONCLUSION

There is no clear evidence of an association between prenatal exposure to PFAS and the cardiometabolic health at earlier stage of pubertal development. However, inverse associations between PFAS and anthropometric measures have been observed in post-menarche girls. While the literature on this topic is scarce in pre-adolescents, these results suggest the importance of considering sex and pubertal stage in these associations.

Multidimensional library for the improved identification of per- and polyfluoroalkyl substances (PFAS)

As the occurrence of human diseases and conditions increase, questions continue to arise about their linkages to chemical exposure, especially for per-and polyfluoroalkyl substances (PFAS). Currently, many chemicals of concern have limited experimental information available for their use in analytical assessments. Here, we aim to increase this knowledge by providing the scientific community with multidimensional characteristics for 175 PFAS and their resulting 281 ion types. Using a platform coupling reversed-phase liquid chromatography (RPLC), electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI), drift tube ion mobility spectrometry (IMS), and mass spectrometry (MS), the retention times, collision cross section (CCS) values, and m/z ratios were determined for all analytes and assembled into an openly available multidimensional dataset. This information will provide the scientific community with essential characteristics to expand analytical assessments of PFAS and augment machine learning training sets for discovering new PFAS.

Understanding the effects of perfluorobutane sulfonate in zebrafish larvae model (Danio rerio): Insights into potential ecotoxicological risks and human health

Perfluorobutane sulfonate (PFBS) is a synthetic organic molecule that belongs to the per and polyfluoroalkyl substances family. Due to its unique physicochemical characteristics, PFBS has been extensively used in consumer products and industries. However, its increasing usage and chemical stability cause environmental pollution and bioaccumulation. The toxicological effects of PFBS were not well studied. In this study, the impact of PFBS on zebrafish embryos was evaluated. PFBS (1000-1500 μM) exposure exhibited increased mortality and malformation in a concentration-dependent manner. After 96 hour post-fertilization of PFBS exposure, the LC50 was estimated to be 1378 μM. Furthermore, PFBS (1.4, 14, 140, 1400 μM) exposure significantly increases oxidative stress by suppressing antioxidant levels. Locomotor behavior analysis revealed that PFBS exposure caused locomotor changes in zebrafish larvae. Acetylcholine esterase activity was also reduced in the PFBS-exposed groups. Gene expression study showed that PFBS exposure downregulated the antioxidant gene expression in zebrafish larvae. Overall, the current study reveals that PFBS can trigger oxidative stress-induced apoptosis by reducing antioxidant activity in zebrafish larvae.

Per- and polyfluoroalkyl substances, apolipoproteins and the risk of coronary heart disease in US men and women

BACKGROUND

Existing evidence for associations of per- and polyfluoroalkyl substances (PFASs) with blood lipids, lipoproteins and apolipoproteins (apo), and coronary heart disease (CHD) risk is limited and inconsistent. This study aims to explore associations between plasma PFASs, blood lipoprotein subspecies defined by apolipoproteins, and CHD risk.

METHODS

A case-control study of CHD was conducted in the Health Professionals Follow-Up Study (HPFS) and Nurses' Health Study (NHS). Among participants initially free of cardiovascular disease at blood collection in 1994 (HPFS) or 1990 (NHS), 101 participants who developed non-fatal myocardial infarction or fatal CHD were identified and confirmed. A healthy control was matched to each case for age, smoking status, and date of blood draw. Plasma levels of perfluorohexane sulfonic acid (PFHxS), perfluorooctanoic acid (PFOA), total perfluorooctane sulfonic acid (PFOS), branched PFOS (brPFOS), linear PFOS (nPFOS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were measured. Conditional logistic regression and cubic spline regression models were used to examine associations between baseline PFASs and CHD risk. Linear regression models were applied to study PFAS associations with lipids and their subfractions.

RESULTS

After multivariate adjustments, total PFOS, brPFOS and nPFOS were significantly associated with increased risk of developing CHD, and HRs (95% CIs) per log(ng/mL) increment of PFASs were 3.66 (1.36-9.89), 3.68 (1.55-8.76), and 3.01 (1.16-7.86), respectively. Significant positive dose-response relationships were identified for these PFASs (Plinearity = 0.01, 0.002, 0.02, respectively). Other PFASs were not associated with CHD risk. PFNA and PFDA were positively associated with total apoE levels among HDL particles with or without apoC-III. No associations were observed for other PFASs with blood lipid subspecies. Blood lipid subfractions did not explain the association between PFOS and CHD risk.

CONCLUSIONS

Plasma PFOS and its isomers were positively associated with CHD risk. These findings suggest that PFOS exposure causes public health risks that are greater than hitherto believed.

Per- and polyfluoroalkyl substances (PFAS) and cancer: Detection methodologies, epidemiological insights, potential carcinogenic mechanisms, and future perspectives

Per- and polyfluoroalkyl substances (PFAS), known as "forever chemicals," are synthetic chemicals which have been used since the 1940s. Given their remarkable thermostability and chemical stability, PFAS have been widely utilized in commercial products, including textiles, surfactants, food packages, nonstick coatings, and fire-fighting foams. Thus, PFAS are widely distributed worldwide and have been detected in human urine, blood, breast milk, tissues and other substances. Growing concerns over the risks of PFAS, including their toxicity and carcinogenicity, have attracted people's attention. Recent reviews have predominantly emphasized advancements in the detection, adsorption, and degradation of PFAS through their chemical structures and toxic properties; however, further examination of the literature is needed to determine the link between PFAS exposure and cancer risk. Here, we introduced different PFAS detection methods based on sensors and liquid chromatography-mass spectrometry (LC-MS). Then, we discussed epidemiological investigations on PFAS levels and cancer risks in recent years, as well as the mechanisms underlying the carcinogenesis. Finally, we proposed the "4C principles" for ongoing exploration and refinement in this field. This review highlights PFAS-cancer associations to fill knowledge gaps and provide evidence-based strategies for future research.

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

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

Comparing the obesogenic effect and regulatory mechanisms of long-term exposure to per/polyfluoroalkyl substances with different terminal groups in Caenorhabditis elegans

Per/polyfluoroalkyl substances (PFASs) are ubiquitous, bioaccumulative, and recalcitrant contaminants, posing global exposure and health risks. The effects of chemical structures on toxicities and the mechanisms of their obesogenic effects were largely unclear. This study used the model organism Caenorhabditis elegans to assess the impact of long-term exposure to different PFASs (PFNA, PFOSA, PFBS, PFHxS, 6:2 FTS, 4:2 FTS, PFOA, and PFOS) on growth and lipid metabolism and discussed the obesogenic mechanisms of selected PFASs. The growth assays indicated longer carbon-fluorine (-CF) chains and total fluorine atoms increased developmental toxicity of PFASs, while at 8 -CF chain-length, PFNA (-COOH terminal), PFOS (-SO3 terminal), and PFOSA (-SO2NH2 terminal) exhibited differential growth inhibition. With the toxicity ranking of PFNA > PFOS > PFOSA, all PFASs significantly induced total lipid accumulation and perturbed the lipid composition in C. elegans. All three PFASs significantly induced lipogenesis gene expression and partially suppressed lipolysis genes. The results suggested that the disruption of lipid metabolism of PFOSA depends on sbp-1, while PFNA and PFOS depend on nhr-49. In conclusion, long-term exposure to PFNA, PFOSA, and PFOS triggers obesogenic effects in organisms by distinct molecular mechanisms.

The role of antibody glycosylation in autoimmune and alloimmune kidney diseases

Immunoglobulin glycosylation is a pivotal mechanism that drives the diversification of antibody functions. The composition of the IgG glycome is influenced by environmental factors, genetic traits and inflammatory contexts. Differential IgG glycosylation has been shown to intricately modulate IgG effector functions and has a role in the initiation and progression of various diseases. Analysis of IgG glycosylation is therefore a promising tool for predicting disease severity. Several autoimmune and alloimmune disorders, including critical and potentially life-threatening conditions such as systemic lupus erythematosus, anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis and antibody-mediated kidney graft rejection, are driven by immunoglobulin. In certain IgG-driven kidney diseases, including primary membranous nephropathy, IgA nephropathy and lupus nephritis, particular glycome characteristics can enhance in situ complement activation and the recruitment of innate immune cells, resulting in more severe kidney damage. Hypofucosylation, hypogalactosylation and hyposialylation are the most common IgG glycosylation traits identified in these diseases. Modulating IgG glycosylation could therefore be a promising therapeutic strategy for regulating the immune mechanisms that underlie IgG-driven kidney diseases and potentially reduce the burden of immunosuppressive drugs in affected patients.

Advances in perfluoro-alkylated compounds (PFAS) detection in seafood and marine environments: A comprehensive review on analytical techniques and global regulations

Per- and poly-fluoroalkyl substances (PFAS) are persistent organic pollutants that severely threaten the environment and human health due to their distinct chemical composition, extensive production, widespread distribution, bioaccumulation in nature, and long-term persistence. This review focuses on the occurrence and sources of PFAS in seafood, with a particular emphasis on advanced detection methods viz. nanoparticle-based, biosensor-based, and metal-organic frameworks-based, and mass spectrometric techniques. The challenges associated with these advanced detection technologies are also discussed. Recent research and regulatory updates about PFAS, including hazardous and potential health effects, epidemiological studies, and various risk assessment models, have been reviewed. In addition, the need for global monitoring programs and regulations on PFAS are critically reviewed by underscoring their crucial role in protecting human health and the environment. Further, approaches for reducing PFAS in seafood are highlighted with future innovative remediation directions. Although advanced PFAS analytical methods are available, selectivity, sample preparation, and sensitivity are still significant challenges associated with detection of PFAS in seafood matrices.  Moreover, crucial research gaps and solutions to essential concerns are critically explored in this review.

Three-year field study on the temporal response of soil microbial communities and functions to PFOA exposure

Contamination of per- and polyfluoroalkyl substances (PFAS) poses a significant threat to soil ecosystem health, yet there remains a lack of understanding regarding the responses of soil microbial communities to prolonged PFAS exposure in field conditions. This study involved a three-year field investigation to track changes in microbial communities and functions in soil subjected to the contamination of a primary PFAS, perfluorooctanoic acid (PFOA). Results showed that PFOA exposure altered soil bacterial and fungal communities in terms of diversity, composition, and structure. Notably, certain bacterial communities with a delayed reaction to PFOA contamination showed the most significant response after one year of exposure. Fungal communities were sensitive to PFOA in soil, exhibiting significant responses within just four months of exposure. After two years, the impact of PFOA on both bacterial and fungal communities was lessened, likely due to the long-term adaptation of microbial communities to PFOA. Moreover, PFOA exposure notably inhibited alkaline phosphatase activity and reduced certain phosphorus cycling-related functional genes after three years of exposure, suggesting potential disruptions in soil fertility. These new insights advance our understanding of the long-term effects of PFOA on soil microbial communities and functions at a field scale.

Per- and Polyfluoroalkyl Substances (PFASs) and Their Potential Effects on Female Reproductive Diseases

Per- and polyfluoroalkyl substances (PFASs) are a class of anthropogenic organic compounds widely present in the natural and human living environments. These emerging persistent pollutants can enter the human body through multiple channels, posing risks to human health. In particular, exposure to PFASs in women may cause a series of reproductive health hazards and infertility. Based on a review of the existing literature, this study preliminarily summarizes the effects of PFAS exposure on the occurrence and development of female reproductive endocrine diseases, such as polycystic ovary syndrome (PCOS), endometriosis, primary ovarian insufficiency (POI), and diminished ovarian reserve (DOR). Furthermore, we outline the relevant mechanisms through which PFASs interfere with the physiological function of the female ovary and finally highlight the role played by nutrients in reducing the reproductive health hazards caused by PFASs. It is worth noting that the physiological mechanisms of PFASs in the above diseases are still unclear. Therefore, it is necessary to further study the molecular mechanisms of PFASs in female reproductive diseases and the role of nutrients in this process.

Association between serum perfluoroalkyl substances concentrations and non-alcoholic fatty liver disease among Korean adults: a cross-sectional study using the National Environmental Health Survey cycle 4

Background

Perfluoroalkyl substances (PFAS) are widely used in industry and daily life due to their useful properties. They have a long half-life, accumulate in the body, and there is evidence that they are associated with biomarkers of lipid metabolism and liver damage. This may suggest non-alcoholic fatty liver disease (NAFLD) caused by PFAS. However, since there has been no study analyzing the relationship between PFAS and NAFLD in the entire population in Korea. We sought to confirm the relationship between serum PFAS concentration and NAFLD prevalence in Korean adults using the Korean National Environmental Health Survey (KoNEHS) cycle 4.

Methods

The study was conducted on 2,529 subjects in 2018-2019 among KoNEHS participants. For the diagnosis of NAFLD, the hepatic steatosis index (HSI) was used, and the geometric mean and concentration distribution of serum PFAS were presented. Logistic regression was performed to confirm the increase in the risk of NAFLD due to changes in PFAS concentration, and the odds ratio and 95% confidence interval (CI) were calculated.

Results

In both adjusted and unadjusted models, an increased odds ratio was observed with increasing serum concentrations of total PFAS and perfluorooctane sulfonate (PFOS) in the non-obese group. In the adjusted model, the odds ratios for serum total PFAS and PFOS were 6.401 (95% CI: 1.883-21.758) and 7.018 (95% CI: 2.688-18.319).

Conclusions

In this study, a higher risk of NAFLD based on HSI was associated with serum total PFAS, PFOS in non-obese group. Further research based on radiological or histological evidence for NAFLD diagnosis and long-term prospective studies are necessary. Accordingly, it is necessary to find ways to reduce exposure to PFAS in industry and daily life.

Association between prenatal exposure to per- and polyfluoroalkyl substances and infant anthropometry: A prospective cohort study

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic organic chemicals with potential endocrine-disrupting effects, and have been found to impair the physical growth of offspring in both experimental and epidemiological studies. We aimed to investigate the effects of prenatal PFAS exposure on repeated measurements of multiple anthropometric indicators in infants.

METHOD

PFAS were measured in serum samples collected from pregnant women at 12-16 gestational weeks. We calculated z-scores for the weight-for-age (WAZ), weight-for-length (WLZ), head circumference-for-age (HCZ), arm circumference-for-age (ACZ), triceps skinfold-for-age (TSZ), and subscapular skinfold-for-age (SSZ) at birth, 6 months, and 12 months of age according to the child growth standards of the World Health Organization (WHO) for anthropometric indicators. A total of 964 mother-infant pairs were included. A multivariate linear regression was performed to examine the associations between prenatal PFAS concentrations and anthropometric indicators at each time point. A generalized estimating equation (GEE) model was used to examine the longitudinal effects of PFAS exposure on repeated measurements of anthropometric indicators. Ultimately, a Bayesian kernel machine regression (BKMR) model was used to assess the joint effects of the PFAS mixture on anthropometric indicators.

RESULTS

In GEE models, perfluorododecanoic acid (PFDoA) in the high tertile group was associated with increased WAZ/WLZ, with β values (95% confidence intervals (CI)) of 0.12 (0.00, 0.23) and 0.18 (0.03, 0.32), respectively. Perfluorononanoic acid (PFNA) was associated with increased ACZ in the middle and high tertile groups. The BKMR models also presented the associations of the PFAS mixture with increased WAZ/WLZ throughout infancy, with more profound effects in females. Meanwhile, a pattern of inverse associations was observed between the perfluorooctanoic acid (PFOA) concentrations in the high tertile group and decreased WAZ, WLZ, and HCZ in males. In addition, the associations between PFAS and increased TSZ/SSZ at birth were identified by both linear regression and BKMR models.

CONCLUSION

Prenatal PFAS exposure (PFNA and PFDoA) was associated with increased infant anthropometry, especially in female infants, while prenatal PFOA exposure was associated with decreased weight, and head and arm circumference in male infants. The findings indicate that prenatal PFAS exposure may impair the growth trajectory of offspring.

A novel method to derive a human safety limit for PFOA by gene expression profiling and modelling

Perfluorooctanoic acid (PFOA) is a persistent environmental contaminant that can accumulate in the human body due to its long half-life. This substance has been associated with liver, pancreatic, testicular and breast cancers, liver steatosis and endocrine disruption. PFOA is a member of a large group of substances also known as "forever chemicals" and the vast majority of substances of this group lack toxicological data that would enable their effective risk assessment in terms of human health hazards. This study aimed to derive a health-based guidance value for PFOA intake (ng/kg BW/day) from in vitro transcriptomics data. To this end, we developed an in silico workflow comprising five components: (i) sourcing in vitro hepatic transcriptomics concentration-response data; (ii) deriving molecular points of departure using BMDExpress3 and performing pathway analysis using gene set enrichment analysis (GSEA) to identify the most sensitive molecular pathways to PFOA exposure; (iii) estimating freely-dissolved PFOA concentrations in vitro using a mass balance model; (iv) estimating in vivo doses by reverse dosimetry using a PBK model for PFOA as part of a quantitative in vitro to in vivo extrapolation (QIVIVE) algorithm; and (v) calculating a tolerable daily intake (TDI) for PFOA. Fourteen percent of interrogated genes exhibited in vitro concentration-response relationships. GSEA pathway enrichment analysis revealed that "fatty acid metabolism" was the most sensitive pathway to PFOA exposure. In vitro free PFOA concentrations were calculated to be 2.9% of the nominal applied concentrations, and these free concentrations were input into the QIVIVE workflow. Exposure doses for a virtual population of 3,000 individuals were estimated, from which a TDI of 0.15 ng/kg BW/day for PFOA was calculated using the benchmark dose modelling software, PROAST. This TDI is comparable to previously published values of 1.16, 0.69, and 0.86 ng/kg BW/day by the European Food Safety Authority. In conclusion, this study demonstrates the combined utility of an "omics"-derived molecular point of departure and in silico QIVIVE workflow for setting health-based guidance values in anticipation of the acceptance of in vitro concentration-response molecular measurements in chemical risk assessment.

Perfluorooctane sulfonate causes pyroptosis and lipid metabolism disorders through ROS-mediated NLRP3 inflammasome activation in grass carp hepatocyte

The surfactant perfluorooctane sulfonate (PFOS) is widely produced worldwide. It is a persistent organic pollutant in the aquatic environment and poses a serious threat to aquatic organisms, as PFOS exposure can cause liver injury in a wide range of organisms. However, it is unclear whether PFOS exposure-induced hepatocellular injury in fish is associated with ROS-mediated activation of NLRP3 inflammasome. In this study, various PFOS concentrations were applied to L8824 cells, a cell line of grass carp hepatocytes. The detrimental impacts of PFOS on oxidative stress, pyroptosis, lipid metabolism, and the discharge of inflammatory factors were examined. MCC950 and N-acetylcysteine were employed to hinder the PFOS-stimulated activation of the NLRP3 inflammasome and the excessive generation of reactive oxygen species in L8824 cells, respectively. This study demonstrated that treatment with PFOS resulted in oxidative stress and activation of NLRP3 inflammasome in L8824 cells. This led to increased expression levels of indicators related to pyroptosis, accompanied by the upregulation of pro-inflammatory cytokine expression as well as downregulation of anti-inflammatory factors. In addition, following PFOS exposure, the expression levels of genes related to lipid synthesis were upregulated and lipid catabolism-related genes were downregulated. Surprisingly, both N-acetylcysteine and MCC950 interventions significantly reduced PFOS-induced L8824 cell pyroptosis and lipid metabolism disorders. In conclusion, this research demonstrated that PFOS drives NLRP3 inflammasome activation through oxidative stress induced by reactive oxygen species overload. This in turn leads to pyroptosis and lipid metabolism disorders.

OMICs Signatures Linking Persistent Organic Pollutants to Cardiovascular Disease in the Swedish Mammography Cohort

Cardiovascular disease (CVD) development may be linked to persistent organic pollutants (POPs), including organochlorine compounds (OCs) and perfluoroalkyl and polyfluoroalkyl substances (PFAS). To explore underlying mechanisms, we investigated metabolites, proteins, and genes linking POPs with CVD risk. We used data from a nested case-control study on myocardial infarction (MI) and stroke from the Swedish Mammography Cohort - Clinical (n = 657 subjects). OCs, PFAS, and multiomics (9511 liquid chromatography-mass spectrometry (LC-MS) metabolite features; 248 proteins; 8110 gene variants) were measured in baseline plasma. POP-related omics features were selected using random forest followed by Spearman correlation adjusted for confounders. From these, CVD-related omics features were selected using conditional logistic regression. Finally, 29 (for OCs) and 12 (for PFAS) unique features associated with POPs and CVD. One omics subpattern, driven by lipids and inflammatory proteins, associated with MI (OR = 2.03; 95% CI = 1.47; 2.79), OCs, age, and BMI, and correlated negatively with PFAS. Another subpattern, driven by carnitines, associated with stroke (OR = 1.55; 95% CI = 1.16; 2.09), OCs, and age, but not with PFAS. This may imply that OCs and PFAS associate with different omics patterns with opposite effects on CVD risk, but more research is needed to disentangle potential modifications by other factors.

Transcriptomic and metabolomic profile changes in the liver of Sprague Dawley rat offspring after maternal PFOS exposure during gestation and lactation

Epidemiological and experimental research has indicated an association between perfluorooctane sulfonate (PFOS) exposure and liver disease. However, the potential hepatotoxic effects and mechanisms of low-level prenatal PFOS exposure in offspring remain ambiguous. The objective of this research was to examine the alterations in liver transcriptomic and metabolomic profiles in offspring rats at postnatal day (PND) 30 following gestational and lactational exposure to PFOS (from gestational day 1 to 20 and PND 1 to 21). Pregnant Sprague-Dawley rats were separated into a control group (3% starch gel solution, oral gavage) and a PFOS exposure group (0.03 mg/kg body weight per day, oral gavage). Histopathological changes in liver sections were observed by hematoxylin and eosin staining. Biochemical analysis was conducted to evaluate changes in glucose and lipid metabolism. Transcriptomic and metabolomic analyses were utilized to identify significant genes and metabolites associated with alterations of liver glucose and lipid metabolism through an integrated multi-omics analysis. No significant differences were found in the measured biochemical parameters. In total, 167 significant differentially expressed genes (DEGs) related to processes such as steroid biosynthesis, PPAR signaling pathway, and fat digestion and absorption were identified in offspring rats in the PFOS exposure group. Ninety-five altered metabolites were exhibited in the PFOS exposure group, such as heptaethylene glycol, lysoPE (0:0/18:0), lucidenic acid K, and p-Cresol sulfate. DEGs associated with steroid biosynthesis, PPAR signaling pathway, fat digestion and absorption were significantly upregulated in the PFOS exposure group (P < 0.05). The analysis of correlations indicated that there was a significant inverse correlation between all identified differential metabolites and the levels of fasting blood glucose, high-density lipoprotein, and triglycerides in the PFOS exposure group (P < 0.05). Our findings demystify that early-life PFOS exposure can lead to alterations in transcriptomic and metabolomic profiles in the offspring's liver, which provided mechanistic insights into the potential hepatotoxicity and developmental toxicity associated with environmentally relevant levels of PFOS exposure.

Per- and polyfluoroalkyl substances and cardiometabolic diseases: A review

Per- and polyfluoroalkyl substances (PFAS) are a group of persistent and widespread environmental pollutants that represent a high concern for human health. They have been shown to be associated with several important physiological processes such as lipid metabolism and the immune system. Consequently, PFAS are suspected to play a role in cardiometabolic disease development. However, the evidence regarding associations between PFAS and overt cardiovascular disease and type 2 diabetes remains limited and inconsistent. To address this, we conducted a review of the epidemiological evidence. A deeper understanding of potential underlying molecular mechanisms may help to explain inconsistencies in epidemiological findings. Thus, to gain more mechanistic insight, we also summarized evidence from omics and laboratory studies into an adverse outcome pathway framework. Our observations indicate the potential for associations of PFAS with multiple molecular pathways that could have opposite associations with disease risk, which could be further modified by mixture composition, lifestyle factors or genetic polymorphisms. This identifies the need for exposome studies considering mixture effects, the use of multi-omics data to gain insight in relevant pathways and the integration of epidemiological and laboratory studies to enhance mechanistic understanding and causal inference. Improved comprehension is essential for environmental health risk assessments.

Systematic transcriptome-wide meta-analysis across endocrine disrupting chemicals reveals shared and unique liver pathways, gene networks, and disease associations

Cardiometabolic disorders (CMD) are a growing public health problem across the world. Among the known cardiometabolic risk factors are compounds that induce endocrine and metabolic dysfunctions, such as endocrine disrupting chemicals (EDCs). To date, how EDCs influence molecular programs and cardiometabolic risks has yet to be fully elucidated, especially considering the complexity contributed by species-, chemical-, and dose-specific effects. Moreover, different experimental and analytical methodologies employed by different studies pose challenges when comparing findings across studies. To explore the molecular mechanisms of EDCs in a systematic manner, we established a data-driven computational approach to meta-analyze 30 human, mouse, and rat liver transcriptomic datasets for 4 EDCs, namely bisphenol A (BPA), bis(2-ethylhexyl) phthalate (DEHP), tributyltin (TBT), and perfluorooctanoic acid (PFOA). Our computational pipeline uniformly re-analyzed pre-processed quality-controlled microarray data and raw RNAseq data, derived differentially expressed genes (DEGs) and biological pathways, modeled gene regulatory networks and regulators, and determined CMD associations based on gene overlap analysis. Our approach revealed that DEHP and PFOA shared stable transcriptomic signatures that are enriched for genes associated with CMDs, suggesting similar mechanisms of action such as perturbations of peroxisome proliferator-activated receptor gamma (PPARγ) signaling and liver gene network regulators VNN1 and ACOT2. In contrast, TBT exhibited highly divergent gene signatures, pathways, network regulators, and disease associations from the other EDCs. In addition, we found that the rat, mouse, and human BPA studies showed highly variable transcriptomic patterns, providing molecular support for the variability in BPA responses. Our work offers insights into the commonality and differences in the molecular mechanisms of various EDCs and establishes a streamlined data-driven workflow to compare molecular mechanisms of environmental substances to elucidate the underlying connections between chemical exposure and disease risks.

Associations of a Prenatal Serum Per- and Polyfluoroalkyl Substance Mixture with the Cord Serum Metabolome in the HOME Study

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous and persistent chemicals associated with multiple adverse health outcomes; however, the biological pathways affected by these chemicals are unknown. To address this knowledge gap, we used data from 264 mother-infant dyads in the Health Outcomes and Measures of the Environment (HOME) Study and employed quantile-based g-computation to estimate covariate-adjusted associations between a prenatal (∼16 weeks' gestation) serum PFAS mixture [perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), and perfluorononanoic acid (PFNA)] and 14,402 features measured in cord serum. The PFAS mixture was associated with four features: PFOS, PFHxS, a putatively identified metabolite (3-monoiodo-l-thyronine 4-O-sulfate), and an unidentified feature (590.0020 m/z and 441.4 s retention time; false discovery rate <0.20). Using pathway enrichment analysis coupled with quantile-based g-computation, the PFAS mixture was associated with 49 metabolic pathways, most notably amino acid, carbohydrate, lipid and cofactor and vitamin metabolism, as well as glycan biosynthesis and metabolism (P(Gamma) <0.05). Future studies should assess if these pathways mediate associations of prenatal PFAS exposure with infant or child health outcomes, such as birthweight or vaccine response.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

DISCUSSION

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

The Association of Hypertension with Perfluoroalkyl and Polyfluoroalkyl Substances

Perfluoroalkyl and polyfluoroalkyl substance (PFAS) is a large group of fluorinated synthetic chemicals, e.g., perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS), perfluorodecanoic acid (PFDA), and perfluorononanoic acid (PFNA). Many epidemiological studies have found that PFAS exposure is associated with hypertension risk, but others possess a different opinion. Overall, the relationship between PFASs and hypertension risk remains controversial. We sought to conduct a systematic review and meta-analysis to clarify the association between PFAS exposure and human risk of hypertension.We conducted a meta-analysis based on population-involving studies published from 1975 to 2023, which we collected from Web of Science, PubMed, and Embase databases. The odds ratio (OR) and standardized mean difference (SMD), with their 95% confidence interval (CI), were used to assess the risk of hypertension with PFAS exposure. The statistical heterogeneity among studies was assessed with the Q-test and I2 statistics. Research publications related to our meta-analysis topic were systematically reviewed.Fourteen studies involving 71,663 participants, in which 26,281 suffered hypertension, met the inclusion criteria. Our analyses suggest that exposure to general PFAS (OR = 1.09, 95% CI = 1.04-1.14) or PFOS (OR = 1.17, 95% CI = 1.05-1.30) is associated with hypertension risk. Specifically, elevated levels of general PFAS (SMD = 0.25, 95% CI = 0.08-0.42), PFHxS (SMD = 0.17, 95% CI = 0.07-0.27), and PFDA (SMD = 0.08, 95% CI = 0.02-0.13) are associated with a high risk of hypertension.Our meta-analysis indicates that PFAS exposure is a risk factor for hypertension, and increased hypertension risk is associated with higher PFAS levels. Further study may eventually provide a better and more comprehensive elucidation of the potential mechanism of this association.

Rutin ameliorates perfluorooctanoic acid-induced testicular injury in mice by reducing oxidative stress and improving lipid metabolism

This study investigated the protective effect of rutin on reproductive and blood-testis barrier (BTB) damage induced by perfluorooctanoic acid (PFOA) exposure. In this study, male ICR mice were randomly divided into three groups, Ctrl group (ddH2O, 5 mL/kg), PFOA group (PFOA, 20 mg/kg/d, 5 mL/kg), PFOA + rutin group (PFOA, 20 mg/kg/d, 5 mL/kg; rutin, 20 mg/kg/d, 5 mL/kg). Mice were exposed to PFOA for 28 days by gavage once daily in the presence or absence of rutin. Histopathological observations demonstrated that rutin treatment during PFOA exposure can reduce structural damage to testis and epididymis such as atrophy of spermatogenic epithelium and stenosis of epididymal lumen, while increase in the number and layers of spermatogenic cells. Biochemical detection demonstrated that rutin can reduce 8-hydroxy-2'-desoxyguanosine (8-OHdG) concentration in the serum and testis tissues. Rutin can also ameliorate glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) content, and reduce malondialdehyde (MDA) and total cholesterol (TC) content in testis tissues. Biotin tracking immunofluorescence and transmission electron microscopy demonstrated that rutin can ameliorate BTB structural damage during PFOA exposure. Rutin ameliorated the stress expression of tight junction proteins occludin and claudin-11. In conclusion, our findings suggested that rutin has a degree of protection in reproductive and BTB damage, which could put forward a new perspective on the application of rutin to prevent reproductive damage.

Association of per- and polyfluoroalkyl substance exposure with metabolic syndrome and its components in adults and adolescents

Per- and polyfluoroalkyl substances (PFAS) are widespread contaminants, but few studies have explored the relationship between PFAS and levels of metabolic syndrome (MetS) in the population. The available evidence of an association is also conflicting. We selected adults and adolescents with complete PFAS data from the National Health and Nutrition Examination Survey conducted between 2003 and 2018. We analyzed the association between PFAS and MetS using multivariate logistic regression models and evaluated potential nonlinear relationships with restricted cubic spline models. Additionally, we employed weighted quantile sum (WQS) regressions to uncover the multiple exposure effects and relative weights of each PFAS. Finally, we conducted a series of sensitivity analyses to test the robustness of our findings. In this population-based study, we analyzed data from a total of 4,973 adults, aged 20-85 years, and 1,381 adolescents, aged 12-19 years. Using fully adjusted multivariate logistic regression models, we found that serum levels of perfluorodecanoate (PFDA) [0.65 (0.50, 0.85)] and total PFAS [0.92 (0.85, 0.99)] were negatively associated with the prevalence of MetS in adults. Similarly, in adolescents, we observed negative correlations between the prevalence of MetS and levels of PFDA [0.55 (0.38, 0.80)], perfluorooctanoic acid (PFOA) [0.62 (0.39, 1.00)], perfluorooctane sulfonic acid (PFOS) [0.59 (0.36, 0.96)], and total PFAS [0.61 (0.37, 0.99)]. Additionally, our study identified statistically significant negative associations between serum levels of PFAS and certain components of MetS, primarily elevated fasting glucose and lower high-density lipoprotein cholesterol. Our study found that PFAS was associated with a lower prevalence of MetS in both adults and adolescents, offering new insights into the relationship between PFAS and metabolic health. Interestingly, however, we observed conflicting findings across the components of MetS. Specifically, we observed that PFAS had a negative correlation with some metrics and a positive correlation with others. These conflicting results point to a complex interplay between PFAS and various metrics of metabolic health.

Plasma levels of per- and polyfluoroalkyl substances (PFAS) and cardiovascular disease - Results from two independent population-based cohorts and a meta-analysis

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are persistent chemicals that have been linked to increased cholesterol levels and thus may have a role in the development of cardiovascular disease (CVD).

OBJECTIVES

To investigate associations between PFAS exposure and incident CVD (a combined CVD end-point consisting of myocardial infarction, ischemic stroke, or heart failure) in two independent population-based cohorts in Sweden. In addition, we performed a meta-analysis also including results from previous studies.

METHODS

In 2,278 subjects aged 45-75 years from the EpiHealth study, the risk of incident CVD in relation to relative plasma levels of perfluorohexanesulfonic acid (PFHxS), perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) was investigated. Associations between plasma levels of six PFAS and incident CVD were also examined in the PIVUS-study (n = 1,016, all aged 70 years). In addition, a meta-analysis was performed including three previous prospective studies, together with the results from the present study.

RESULTS

There were no overall statistically significant associations between levels of the different PFAS and incident CVD, neither in EpiHealth nor in PIVUS. However, there was a significant sex interaction for PFOS in EpiHealth (p = 0.008), and an inverse association could be seen only in men (Men, HR: 0.68, 95 % CI: 0.52, 0.89) (Women, HR: 1.13, 95 % CI: 0.82, 1.55). A meta-analysis of five independent studies regarding PFOA and incident CVD showed a risk ratio (RR) of 0.80 (CI: 0.66, 0.94) when high levels were compared to low levels.

CONCLUSIONS

This longitudinal study using data from two population-based cohort studies in Sweden did not indicate any increased risk of incident CVD for moderately elevated PFAS levels. A meta-analysis of five independent cohort studies rather indicated a modest inverse association between PFOA levels and incident CVD, further supporting that increasing PFAS levels are not linked to an increased risk of CVD.

Regulation of cholesterol metabolism: New players for an old physiological process

Identified more than two centuries ago, cholesterol plays a pivotal role in human physiology. Since cholesterol metabolism is a physiologically significant process, it is not surprising that its alterations are associated with several pathologies. The discovery of new molecular targets or compounds able to modulate this sophisticated metabolism has been capturing the attention of research groups worldwide since many years. Endogenous and exogenous compounds are known to regulate cellular cholesterol synthesis and uptake, or reduce cholesterol absorption at the intestinal level, thereby regulating cholesterol homeostasis. However, there is a great need of new modulators and diverse new pathways have been uncovered. Here, after illustrating cholesterol metabolism and its well-known regulators, some new players of this important physiological process are also described.

Associations between per- and polyfluoroalkyl substances (PFAS) and diabetes in two population-based cohort studies from Sweden

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) have been suggested to contribute to the development of metabolic diseases such as obesity, diabetes and non-alcoholic fatty liver disease (NAFLD). However, evidence from epidemiological studies remain divergent. The aim of the present study was to evaluate associations between PFAS exposure and prevalent diabetes in a cross-sectional analysis and fasting glucose in a longitudinal analysis.

METHODS

In 2373 subjects aged 45-75 years from the EpiHealth study, three PFAS; perfluorohexanesulfonic acid (PFHxS), perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were analyzed in plasma together with information on prevalent diabetes. Participants in the PIVUS study (n = 1016 at baseline, all aged 70 years) were followed over 10 years regarding changes in plasma levels of six PFAS; PFHxS, PFOA, PFOS, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA), and changes in plasma levels of fasting glucose.

RESULTS

In the EpiHealth study, no overall associations could be observed between the levels of PFOA, PFOS or PFHxS and prevalent diabetes. However, there was a significant sex-interaction for PFOA (p = 0.02), and an inverse association could be seen between PFOA (on a SD-scale) and prevalent diabetes in women only (OR: 0.71, 95% CI: 0.52, 0.96, p-value: 0.02). This association showed a non-monotonic dose-response curve. In the PIVUS study, inverse relationships could be observed between the changes in levels (ln-transformed) of PFOA and PFUnDA vs the change in fasting glucose levels (ln-transformed) over 10 years (p = 0.04 and p = 0.02, respectively). As in EpiHealth, these inverse associations were significant only in women (PFOA: β: -0.03, p = 0.02, PFUnDA: β: -0.03, p = 0.03).

IMPACT

Exposure to per- and polyfluoroalkyl substances (PFAS) has been linked to unfavorable human health, including metabolic disorders such as obesity, diabetes and non-alcoholic fatty liver disease. However, results from in vivo, in vitro and epidemiological studies are incoherent. The aim of the present study was therefore to investigate associations between PFAS and diabetes in a cross-sectional study and glucose levels in a longitudinal study. Results show inverse associations in women only. Results also display non-monotonic dose response curves (i.e., that only low levels of PFOA are related to higher probability of prevalent diabetes). This suggests that sex differences and complex molecular mechanisms may underlie the observed findings. A better understanding of the factors and molecular mechanisms contributing to such differences is recognized as an important direction for future research.

CONCLUSIONS

PFOA was found to be inversely related to both prevalent diabetes and changes in plasma glucose levels among women only. Thus, our findings suggest there are sex differences in the inverse relationship of PFOA and type 2 diabetes and glucose levels.

The interference between effects of PFAS exposure on thyroid hormone disorders and cholesterol levels: an NHANES analysis

Studies have documented that per- and polyfluoroalkyl substance (PFAS) exposures are associated with thyroid hormones (TH) and lipid levels. This study investigates whether these effects interfere with each other. We analyzed data on 3954 adults in the US National Health and Nutrition Examination Survey (NHANES; 2007-2012). TH disorder was defined using thyroid hormones. Serum high-density lipoprotein (HDL) cholesterol, total cholesterol, and six types of PFAS were included. Weighted quantile sum (WQS) regression was used to estimate the overall effect of PFAS mixture on TH disorder and cholesterols, respectively. Potential confounders, including age, race, gender, education, household poverty, smoking, and alcohol drinking, were adjusted. PFAS mixture was associated increased risk for TH disorder (odds ratio = 1.21, 95% confidence interval (CI): 1.02, 1.43), higher HDL cholesterol (linear coefficient = 1.31, 95% CI: 0.50, 2.11), and higher total cholesterol (linear coefficient = 5.30, 95% CI: 3.40, 7.21). TH disorder was associated with higher HDL cholesterol (linear coefficient = 2.30, 95% CI: 0.50, 2.11), but not total cholesterol. When adjusted for TH disorder, the effect estimates of PFAS mixture remain roughly unchanged on HDL cholesterol (linear coefficient = 1.13, 95% CI: 0.28, 1.98) and total cholesterol (linear coefficient = 5.61, 95% CI: 3.58, 7.63). Sex modified the effect of PFAS mixture on HDL cholesterol (P for interaction: 0.04) but did not change the interaction between PFAS and TH disorder on cholesterols. We corroborated the adverse health effects of PFAS exposure on TH and lipids; however, these two effects appear to be independent of and not interfere with each other.

Current Review of Increasing Animal Health Threat of Per- and Polyfluoroalkyl Substances (PFAS): Harms, Limitations, and Alternatives to Manage Their Toxicity

Perfluorinated and polyfluorinated alkyl substances (PFAS), more than 4700 in number, are a group of widely used man-made chemicals that accumulate in living things and the environment over time. They are known as "forever chemicals" because they are extremely persistent in our environment and body. Because PFAS have been widely used for many decades, their presence is evident globally, and their persistence and potential toxicity create concern for animals, humans and environmental health. They can have multiple adverse health effects, such as liver damage, thyroid disease, obesity, fertility problems, and cancer. The most significant source of living exposure to PFAS is dietary intake (food and water), but given massive industrial and domestic use, these substances are now punctually present not only domestically but also in the outdoor environment. For example, livestock and wildlife can be exposed to PFAS through contaminated water, soil, substrate, air, or food. In this review, we have analyzed and exposed the characteristics of PFAS and their various uses and reported data on their presence in the environment, from industrialized to less populated areas. In several areas of the planet, even in areas far from large population centers, the presence of PFAS was confirmed, both in marine and terrestrial animals (organisms). Among the most common PFAS identified are undoubtedly perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA), two of the most widely used and, to date, among the most studied in terms of toxicokinetics and toxicodynamics. The objective of this review is to provide insights into the toxic potential of PFAS, their exposure, and related mechanisms.

Integrating -omics approaches into population-based studies of endocrine disrupting chemicals: A scoping review

Health effects of endocrine disrupting chemicals (EDCs) are challenging to detect in the general population. Omics technologies become increasingly common to identify early biological changes before the apparition of clinical symptoms, to explore toxic mechanisms and to increase biological plausibility of epidemiological associations. This scoping review systematically summarises the application of omics in epidemiological studies assessing EDCs-associated biological effects to identify potential gaps and priorities for future research. Ninety-eight human studies (2004-2021) were identified through database searches (PubMed, Scopus) and citation chaining and focused on phthalates (34 studies), phenols (19) and PFASs (17), while PAHs (12) and recently-used pesticides (3) were less studied. The sample sizes ranged from 10 to 12,476 (median = 159), involving non-pregnant adults (38), pregnant women (11), children/adolescents (15) or both latter populations studied together (23). Several studies included occupational workers (10) and/or highly exposed groups (11) focusing on PAHs, PFASs and pesticides, while studies on phenols and phthalates were performed in the general population only. Analysed omics layers included metabolic profiles (30, including 14 targeted analyses), miRNA (13), gene expression (11), DNA methylation (8), microbiome (5) and proteins (3). Twenty-one studies implemented targeted multi-assays focusing on clinical routine blood lipid traits, oxidative stress or hormones. Overall, DNA methylation and gene expression associations with EDCs did not overlap across studies, while some EDC-associated metabolite groups, such as carnitines, nucleotides and amino acids in untargeted metabolomic studies, and oxidative stress markers in targeted studies, were consistent across studies. Studies had common limitations such as small sample sizes, cross-sectional designs and single sampling for exposure biomonitoring. In conclusion, there is a growing body of evidence evaluating the early biological responses to exposure to EDCs. This review points to a need for larger longitudinal studies, wider coverage of exposures and biomarkers, replication studies and standardisation of research methods and reporting.

Liver and cardiometabolic markers and conditions in a cross-sectional study of three Australian communities living with environmental per- and polyfluoroalkyl substances contamination

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) have been associated with higher cholesterol and liver function markers in some studies, but the evidence for specific cardiometabolic conditions has been inconclusive.

OBJECTIVES

We quantified the associations of single and combined PFAS with cardiometabolic markers and conditions in a cross-sectional study of three Australian communities with PFAS-contaminated water from the historical use of aqueous film-forming foam in firefighting activities, and three comparison communities.

METHODS

Participants gave blood samples for measurement of nine PFAS, four lipids, six liver function markers, and completed a survey on sociodemographic characteristics and eight cardiometabolic conditions. We estimated differences in mean biomarker concentrations per doubling in single PFAS concentrations (linear regression) and per interquartile range increase in the PFAS mixture (Bayesian kernel machine regression). We estimated prevalence ratios of biomarker concentrations outside reference limits and self-reported cardiometabolic conditions (Poisson regression).

RESULTS

We recruited 881 adults in exposed communities and 801 in comparison communities. We observed higher mean total cholesterol with higher single and mixture PFAS concentrations in blood serum (e.g., 0.18 mmol/L, 95% credible interval -0.06 to 0.42, higher total cholesterol concentrations with an interquartile range increase in all PFAS concentrations in Williamtown, New South Wales), with varying certainty across communities and PFAS. There was less consistency in direction of associations for liver function markers. Serum perfluorooctanoic acid (PFOA) concentrations were positively associated with the prevalence of self-reported hypercholesterolemia in one of three communities, but PFAS concentrations were not associated with self-reported type II diabetes, liver disease, or cardiovascular disease.

DISCUSSION

Our study is one of few that has simultaneously quantified the associations of blood PFAS concentrations with multiple biomarkers and cardiometabolic conditions in multiple communities. Our findings for total cholesterol were consistent with previous studies; however, substantial uncertainty in our estimates and the cross-sectional design limit causal inference.

Gene-environment interactions in the associations of PFAS exposure with insulin sensitivity and beta-cell function in a Faroese cohort followed from birth to adulthood

BACKGROUND

Exposure to perfluoroalkyl substances (PFAS) has been associated with changes in insulin sensitivity and pancreatic beta-cell function in humans. Genetic predisposition to diabetes may modify these associations; however, this hypothesis has not been yet studied.

OBJECTIVES

To evaluate genetic heterogeneity as a modifier in the PFAS association with insulin sensitivity and pancreatic beta-cell function, using a targeted gene-environment (GxE) approach.

METHODS

We studied 85 single-nucleotide polymorphisms (SNPs) associated with type 2 diabetes, in 665 Faroese adults born in 1986-1987. Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were measured in cord whole blood at birth and in participants' serum from age 28 years. We calculated the Matsuda-insulin sensitivity index (ISI) and the insulinogenic index (IGI) based on a 2 h-oral glucose tolerance test performed at age 28. Effect modification was evaluated in linear regression models adjusted for cross-product terms (PFAS*SNP) and important covariates.

RESULTS

Prenatal and adult PFOS exposures were significantly associated with decreased insulin sensitivity and increased beta-cell function. PFOA associations were in the same direction but attenuated compared to PFOS. A total of 58 SNPs were associated with at least one PFAS exposure variable and/or Matsuda-ISI or IGI in the Faroese population and were subsequently tested as modifiers in the PFAS-clinical outcome associations. Eighteen SNPs showed interaction p-values (PGxE) < 0.05 in at least one PFAS-clinical outcome association, five of which passed False Discovery Rate (FDR) correction (PGxE-FDR<0.20). SNPs for which we found stronger evidence for GxE interactions included ABCA1 rs3890182, FTO rs9939609, FTO rs3751812, PPARG rs170036314 and SLC12A3 rs2289116 and were more clearly shown to modify the PFAS associations with insulin sensitivity, rather than with beta-cell function.

DISCUSSION

Findings from this study suggest that PFAS-associated changes in insulin sensitivity could vary between individuals as a result of genetic predisposition and warrant replication in independent larger populations.

Associations between Per- and Polyfluoroalkyl Substances Exposures and Blood Lipid Levels among Adults-A Meta-Analysis

BACKGROUND

Associations between per- and polyfluoroalkyl substances (PFAS) and blood lipid levels in humans were mixed.

OBJECTIVES

The objective of this meta-analysis was to summarize associations between PFAS and blood lipids in adults.

METHODS

A literature search was conducted on PubMed and Web of Science for articles published through 13 May 2022 that examined associations between PFAS and blood lipids, including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triacylglycerols (TGs). Inclusion criteria included the presence of associations between five PFAS (PFOA, PFOS, PFHxS, PFDA, and PFNA) and four blood lipid measures (TC, HDL-C, LDL-C, and TGs) in adults. Data on study characteristics and PFAS-lipid associations were extracted. Assessments of individual study quality were performed. Associations of changes of blood lipid levels corresponding to 1 interquartile range (IQR)-unit increase of blood PFAS levels were pooled using random effects models. Dose-response relationships were examined.

RESULTS

Twenty-nine publications were included in the present analyses. Every IQR increase of PFOA was significantly associated with a 2.1 -mg / dL increase in TC (95% CI: 1.2, 3.0), a 1.3 -mg / dL increase in TGs (95% CI: 0.1, 2.4), and a 1.4 -mg / dL increase in LDL-C (95% CI: 0.6, 2.2). PFOS was also significantly associated with TC and LDL-C levels, and the corresponding values were 2.6 (95% CI: 1.5, 3.6) and 1.9 (95% CI: 0.9, 3.0), respectively. Associations of PFOS and PFOA with HDL-C levels were largely null. For minor PFAS species, PFHxS was significantly associated with higher levels of HDL-C [0.8 (95% CI: 0.5, 1.2)]. Inverse associations were observed between PFDA and TGs [- 5.0 (95% CI: - 8.1 , - 1.9 )] and between PFNA and TGs [- 1.7 (95% CI: - 3.5 , - 0.02 )], whereas a positive association was observed between PFDA and HDL-C [1.4 (95% CI: 0.1, 2.7)]. Nonsignificant nonlinear dose-response relationships were identified for associations of PFOA and PFOS with certain blood lipids.

DISCUSSION

PFOA and PFOS were significantly associated with TC and LDL-C levels in adults. Whether these findings may translate into an elevated cardiovascular disease risk associated with PFAS exposure warrants further investigation. https://doi.org/10.1289/EHP11840.

Integrated lipidomics and transcriptomics analysis reveal lipid metabolism disturbance in scallop (Chlamys farreri) exposure to benzo[a]pyrene

Benzo[a]pyrene (B[a]P) commonly bioaccumulates in lipid-rich tissues due to its lipophilicity and further affects lipid metabolism. The present study systematically investigated the lipid metabolism disturbance in digestive glands of scallops (Chlamys farreri) exposure to B[a]P, based on lipidomics, transcriptomics, molecular and biochemical analysis. We exposed the scallops to environmentally relevant concentrations of B[a]P for 21 days. The bioaccumulation of B[a]P, lipid content and lipid peroxidation in digestive glands were measured. Integrated lipidomics and transcriptomics analysis, the differential lipid species were identified and key genes based on the pathways in which genes and lipid species involved together were selected in scallop exposure to 10 μg/L B[a]P. The changes of lipid profile showed that triglycerides (TGs) were accumulated after 21 days exposure, while the phospholipids (PLs) decreased demonstrated membrane structures were disrupted by B[a]P. In combination with the change of gene expression, we speculated that B[a]P could induce lipids accumulation by up-regulating lipid synthesis-related genes expression, down-regulating lipolysis-related genes expression and interfering with lipid transport. Overall, this study provides new insights into the mechanisms of lipid metabolism disturbance in bivalves exposed to PAHs, and establishes a foundation for understanding the bioaccumulation mechanism of B[a]P in aquatic organisms, which is of great importance for further ecotoxicological study.

PFASs: What can we learn from the European Human Biomonitoring Initiative HBM4EU

Per- and polyfluoroalkyl substances (PFASs) were one of the priority substance groups selected which have been investigated under the ambitious European Joint programme HBM4EU (2017-2022). In order to answer policy relevant questions concerning exposure and health effects of PFASs in Europe several activities were developed under HBM4EU namely i) synthesis of HBM data generated in Europe prior to HBM4EU by developing new platforms, ii) development of a Quality Assurance/Quality Control Program covering 12 biomarkers of PFASs, iii) aligned and harmonized human biomonitoring studies of PFASs. In addition, some cohort studies (on mother-child exposure, occupational exposure to hexavalent chromium) were initiated, and literature researches on risk assessment of mixtures of PFAS, health effects and effect biomarkers were performed. The HBM4EU Aligned Studies have generated internal exposure reference levels for 12 PFASs in 1957 European teenagers aged 12-18 years. The results showed that serum levels of 14.3% of the teenagers exceeded 6.9 μg/L PFASs, which corresponds to the EFSA guideline value for a tolerable weekly intake (TWI) of 4.4 ng/kg for some of the investigated PFASs (PFOA, PFOS, PFNA and PFHxS). In Northern and Western Europe, 24% of teenagers exceeded this level. The most relevant sources of exposure identified were drinking water and some foods (fish, eggs, offal and locally produced foods). HBM4EU occupational studies also revealed very high levels of PFASs exposure in workers (P95: 192 μg/L in chrome plating facilities), highlighting the importance of monitoring PFASs exposure in specific workplaces. In addition, environmental contaminated hotspots causing high exposure to the population were identified. In conclusion, the frequent and high PFASs exposure evidenced by HBM4EU strongly suggests the need to take all possible measures to prevent further contamination of the European population, in addition to adopting remediation measures in hotspot areas, to protect human health and the environment. HBM4EU findings also support the restriction of the whole group of PFASs. Further, research and definition for additional toxicological dose-effect relationship values for more PFASs compounds is needed.

Firefighters' exposure to per-and polyfluoroalkyl substances (PFAS) as an occupational hazard: A review

The term "firefighter" and "cancer" have become so intertwined in the past decade that they are now nearly inseparable. Occupational exposure of firefighters to carcinogenic chemicals may increase their risk of developing different types of cancer. PFAS are one of the major classes of carcinogenic chemicals that firefighters are exposed to as occupational hazard. Elevated levels of PFAS have been observed in firefighters' blood serum in recent studies. Possible sources of occupational exposure to PFAS include turnout gear, aqueous film-forming foam, and air and dust at both the fire scene and fire station. Preliminary discussion on PFAS includes definition, classification, and chemical structure. The review is then followed by identifying the sources of PFAS that firefighters may encounter as an occupational hazard. The structural properties of the PFAS used in identified sources, their degradation, and exposure pathways are reviewed. The elevated level of PFAS in the blood serum and how this might associate with an increased risk of cancer is discussed. Our review shows a significant amount of PFAS on turnout gear and their migration to untreated layers, and how turnout gear itself might be a potential source of PFAS exposure. PFAS from aqueous film-forming foams (AFFF), air, and dust of fire stations have been already established as potential exposure sources. Studies on firefighters' cancer suggest that firefighters have a higher cancer risk compared to the general population. This review suggests that increased exposure to PFAS as an occupational hazard could be a potential cancer risk for firefighters.

A review of cardiovascular effects and underlying mechanisms of legacy and emerging per- and polyfluoroalkyl substances (PFAS)

Cardiovascular disease (CVD) poses the leading threats to human health and life, and their occurrence and severity are associated with exposure to environmental pollutants. Per- and polyfluoroalkyl substances (PFAS), a group of widely used industrial chemicals, are characterized by persistence, long-distance migration, bioaccumulation, and toxicity. Some PFAS, particularly perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexanesulfonic acid (PFHxS), have been banned, leaving only legacy exposure to the environment and human body, while a number of novel PFAS alternatives have emerged and raised concerns, such as polyfluoroalkyl ether sulfonic and carboxylic acid (PFESA and PFECA) and sodium p-perfluorous nonenoxybenzene sulfonate (OBS). Overall, this review systematically elucidated the adverse cardiovascular (CV) effects of legacy and emerging PFAS, emphasized the dose/concentration-dependent, time-dependent, carbon chain length-dependent, sex-specific, and coexposure effects, and discussed the underlying mechanisms and possible prevention and treatment. Extensive epidemiological and laboratory evidence suggests that accumulated serum levels of legacy PFAS possibly contribute to an increased risk of CVD and its subclinical course, such as cardiac toxicity, vascular disorder, hypertension, and dyslipidemia. The underlying biological mechanisms may include oxidative stress, signaling pathway disturbance, lipid metabolism disturbance, and so on. Various emerging alternatives to PFAS also play increasingly prominent toxic roles in CV outcomes that are milder, similar to, or more severe than legacy PFAS. Future research is recommended to conduct more in-depth CV toxicity assessments of legacy and emerging PFAS and explore more effective surveillance, prevention, and treatment strategies, accordingly.

Gut Microbiome-Host Metabolome Homeostasis upon Exposure to PFOS and GenX in Male Mice

Alterations of the normal gut microbiota can cause various human health concerns. Environmental chemicals are one of the drivers of such disturbances. The aim of our study was to examine the effects of exposure to perfluoroalkyl and polyfluoroalkyl substances (PFAS)-specifically, perfluorooctane sulfonate (PFOS) and 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy) propanoic acid (GenX)-on the microbiome of the small intestine and colon, as well as on liver metabolism. Male CD-1 mice were exposed to PFOS and GenX in different concentrations and compared to controls. GenX and PFOS were found to have different effects on the bacterial community in both the small intestine and colon based on 16S rRNA profiles. High GenX doses predominantly led to increases in the abundance of Clostridium sensu stricto, Alistipes, and Ruminococcus, while PFOS generally altered Lactobacillus, Limosilactobacillus, Parabacteroides, Staphylococcus, and Ligilactobacillus. These treatments were associated with alterations in several important microbial metabolic pathways in both the small intestine and colon. Untargeted LC-MS/MS metabolomic analysis of the liver, small intestine, and colon yielded a set of compounds significantly altered by PFOS and GenX. In the liver, these metabolites were associated with the important host metabolic pathways implicated in the synthesis of lipids, steroidogenesis, and in the metabolism of amino acids, nitrogen, and bile acids. Collectively, our results suggest that PFOS and GenX exposure can cause major perturbations in the gastrointestinal tract, aggravating microbiome toxicity, hepatotoxicity, and metabolic disorders.

Perfluoroalkyl Substance Serum Concentrations and Cholesterol Absorption-Inhibiting Medication Ezetimibe

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are human-made compounds with a widespread presence in human blood and other organs. PFAS have been associated with multiple health effects, including higher serum cholesterol and LDL cholesterol.

OBJECTIVE

Potential population differences in serum PFAS attributable to ezetimibe, a medication that inhibits cholesterol absorption, are of interest for several reasons. The "C8" Health Project survey data from six contaminated water districts in the mid-Ohio Valley of the United States provide a wide enough range of serum PFAS and a sufficient number of ezetimibe takers to explore this topic.

METHODS

A total of 44,126 adult participants of the C8 Health Survey were included in the community-based study. The status of taking (1075) or non-taking of ezetimibe, alone or in combination with another lipid-lowering agent, was acquired. The geometric mean serum concentrations of the four most commonly detected serum PFAS were compared based on the status of ezetimibe use.

RESULTS

There is no significant difference in serum concentrations of perfluorohexanesulfonic acid (PFHxS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and perfluorononanoic acid (PFNA) between ezetimibe users and non-users after adjustment for age, sex, body mass index, estimated glomerular filtration rate (eGFR), cigarette smoking, education, and average household income.

CONCLUSION

The sterol absorption-inhibiting medication ezetimibe does not appear to affect serum PFAS concentrations. We sought but did not find direct evidence that ezetimibe could inhibit PFAS uptake nor inferential evidence that inter-individual differences in sterol absorption could provide a confounding factor explanation for the association of serum total- and LDL-cholesterol with serum PFAS.

Chemicals/materials of emerging concern in farmlands: sources, crop uptake and potential human health risks

Certain chemicals/materials that are contaminants of emerging concern (CECs) have been widely detected in water bodies and terrestrial systems worldwide while other CECs occur at undetectable concentrations. The primary sources of CECs in farmlands are agricultural inputs, such as wastewater, biosolids, sewage sludge, and agricultural mulching films. The percent increase in cropland area during 1950-2016 was 30 and the rise in land use for food crops during 1960-2018 was 100-500%, implying that there could be a significant CEC burden in farmlands in the future. In fact, the alarming concentrations (μg kg^-1) of certain CECs such as PBDEs, PAEs, and PFOS that occur in farmlands are 383, 35 400 and 483, respectively. Also, metal nanoparticles are reported even at the mg kg^-1 level. Chronic root accumulation followed by translocation of CECs into plants results in their detectable concentrations in the final plant produce. Thus, there is a continuous flow of CECs from farmlands to agricultural produce, causing a serious threat to the terrestrial food chain. Consequently, CECs find their way to the human body directly through CEC-laden plant produce or indirectly via the meat of grazing animals. Thus, human health could be at the most critical risk since several CECs have been shown to cause cancers, disruption of endocrine and cognitive systems, maternal-foetal transfer, neurotoxicity, and genotoxicity. Overall, this comprehensive review provides updated information on contamination of chemicals/materials of concern in farmlands globally, sources for their entry, uptake by crop plants, and their likely impact on the terrestrial food chain and human health.

Plasma PFOA and PFOS Levels, DNA Methylation, and Blood Lipid Levels: A Pilot Study

Exposure to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) is associated with blood lipids in adults, but the underlying mechanisms remain unclear. This pilot study aimed to investigate the associations between PFOA or PFOS and epigenome-wide DNA methylation and assess the mediating effect of DNA methylation on the PFOA/PFOS-blood lipid association. We measured plasma PFOA/PFOS and leukocyte DNA methylation in 98 patients enrolled from the hospital between October 2018 and August 2019. The median plasma PFOA/PFOS levels were 0.85 and 2.29 ng/mL. Plasma PFOA and PFOS levels were significantly associated with elevated total cholesterol (TC) and low-density lipoprotein cholesterol (LDL) levels. There were 63/87 CpG positions and 8/11 differentially methylated regions (DMRs) associated with plasma PFOA/PFOS levels, respectively. In addition, 5 CpG positions (annotated to AFF3, CREB5, NRG2, USF2, and intergenic region) and one DMR annotated to IRF6 may mediate the association between plasma PFOA/PFOS and LDL levels (mediated proportion from 7.29 to 46.77%); two CpG positions may mediate the association between plasma PFOA/PFOS and TC levels (annotated to CREB5 and USF2, mediated proportion is around 30%). The data suggest that PFOA/PFOS exposure alters DNA methylation. More importantly, the association of PFOA/PFOS with lipid indicators was partly mediated by DNA methylation changes in lipid metabolism-related genes.

Associations between serum perfluoroalkyl acid (PFAA) concentrations and health related biomarkers in firefighters

Firefighters who used aqueous film forming foam in the past have experienced elevated exposures to perfluoroalkyl acids (PFAAs). The objective of this study was to examine the associations between clinical chemistry endpoints and serum concentrations of perfluorooctanoic acid (PFOA), perfluorohexane sulfonate (PFHxS), perfluoroheptane sulfonate (PFHpS) and perfluorooctane sulfonate (PFOS) in firefighters. Multiple linear regression was used to assess relationships between PFAA serum concentrations and biochemical markers for cardiovascular disease, kidney-, liver- and thyroid function, in a cross-sectional survey of 783 firefighters with elevated levels of PFHxS, PFHpS and PFOS in relation to the most recently reported levels in the general Australian population. Linear logistic regression was used to assess the odds ratios for selected self-reported health outcomes. Repeated measures linear mixed models were further used to assess relationships between PFAAs and biomarkers for cardiovascular disease and kidney function longitudinally in a subset of the firefighters (n = 130) where serum measurements were available from two timepoints, five years apart. In the cross-sectional analysis, higher levels of all PFAAs were significantly associated with higher levels of biomarkers for cardiovascular disease (total-cholesterol, and LDL-cholesterol). For example, doubling in PFOS serum concentration were associated with increases in total cholesterol (β:0.111, 95% confidence interval (95%CI): 0.026, 0.195 mmol/L) and LDL-cholesterol (β: 0.104, 95%CI:0.03, 0.178 mmol/L). Doubling in PFOA concentration, despite not being elevated in the study population, were additionally positively associated with kidney function marker urate (e.g., β: 0.010, 95%CI; 0.004, 0.016 mmol/L) and thyroid function marker TSH (e.g., β: 0.087, 95%CI: 0.014, 0.161 mIU/L). PFAAs were not associated with any assessed self-reported health conditions. No significant relationships were observed in the longitudinal analysis. Findings support previous studies, particularly on the association between PFAAs and serum lipids.

Characterization of Potential Adverse Outcome Pathways Related to Metabolic Outcomes and Exposure to Per- and Polyfluoroalkyl Substances Using Artificial Intelligence

Human exposure to per- and polyfluoroalkyl substances (PFAS) has been associated with numerous adverse health effects, depending on various factors such as the conditions of exposure (dose/concentration, duration, route of exposure, etc.) and characteristics associated with the exposed target (e.g., age, sex, ethnicity, health status, and genetic predisposition). The biological mechanisms by which PFAS might affect systems are largely unknown. To support the risk assessment process, AOP-helpFinder, a new artificial intelligence tool, was used to rapidly and systematically explore all available published information in the PubMed database. The aim was to identify existing associations between PFAS and metabolic health outcomes that may be relevant to support building adverse outcome pathways (AOPs). The collected information was manually organized to investigate linkages between PFAS exposures and metabolic health outcomes, including dyslipidemia, hypertension, insulin resistance, and obesity. Links between PFAS exposure and events from the existing metabolic-related AOPs were also retrieved. In conclusion, by analyzing dispersed information from the literature, we could identify some associations between PFAS exposure and components of existing AOPs. Additionally, we identified some linkages between PFAS exposure and metabolic outcomes for which only sparse information is available or which are not yet present in the AOP-wiki database that could be addressed in future research.

Factors Modulating COVID-19: A Mechanistic Understanding Based on the Adverse Outcome Pathway Framework

Addressing factors modulating COVID-19 is crucial since abundant clinical evidence shows that outcomes are markedly heterogeneous between patients. This requires identifying the factors and understanding how they mechanistically influence COVID-19. Here, we describe how eleven selected factors (age, sex, genetic factors, lipid disorders, heart failure, gut dysbiosis, diet, vitamin D deficiency, air pollution and exposure to chemicals) influence COVID-19 by applying the Adverse Outcome Pathway (AOP), which is well-established in regulatory toxicology. This framework aims to model the sequence of events leading to an adverse health outcome. Several linear AOPs depicting pathways from the binding of the virus to ACE2 up to clinical outcomes observed in COVID-19 have been developed and integrated into a network offering a unique overview of the mechanisms underlying the disease. As SARS-CoV-2 infectibility and ACE2 activity are the major starting points and inflammatory response is central in the development of COVID-19, we evaluated how those eleven intrinsic and extrinsic factors modulate those processes impacting clinical outcomes. Applying this AOP-aligned approach enables the identification of current knowledge gaps orientating for further research and allows to propose biomarkers to identify of high-risk patients. This approach also facilitates expertise synergy from different disciplines to address public health issues.