Associations of Perfluoroalkyl substances with blood lipids and Apolipoproteins in lipoprotein subspecies: the POUNDS-lost study

Assessing the effects of fluorine-free and PFAS-containing firefighting foams on development and behavioral responses using a zebrafish-based platform

Significant progress has been made in developing fluorine-free firefighting foams (F3) as alternatives to perfluoroalkyl substances (PFAS)-containing aqueous film-forming foams (AFFF) to help eliminate the health and environmental concerns linked to PFAS exposure. However, developing viable F3 options hinges on a thorough assessment of potential risks alongside the technical performance evaluations. This study showcases the capability of a zebrafish-based platform to discern the developmental and behavioral toxicities associated with exposure to one AFFF and two F3 formulations. To facilitate direct exposure to the chemicals, embryos were enzymatically dechorionated and then exposed to the diluted formulations (6-120 hours post fertilization (hpf)) at concentrations folding from 0.1% of the manufacturer-recommended working concentrations. The exposure regimen also included daily automated media changes (50%) and mortality assessments (24 and 120 hpf). At 120 hpf, a comprehensive assessment encompassing overall development, prevalence of morphological defects, and behavioral responses to acute stressors (visual, acoustic, and peripheral irritant) was conducted. Exposure to both F3s significantly increased larval mortalities to percentages exceeding 90%, whereas AFFF exposures did not cause any significant effect. Overall development, marked by total larval length, was significantly impacted following exposures to all foams. Behavioral responses to acute stressors were also significantly altered following exposures to both F3s, whereas the AFFF did not alter behavior at the concentrations tested. Our findings demonstrate toxicities associated with tested F3 formulations that encompass several endpoints and highlight the utility of the proposed platform in evaluating the developmental toxicities of current and future foam formulations.

Transplacental transfer of perfluorinated and poly-fluorinated substances in maternal-cord serum and association with birth weight: A birth cohort study, China

Although the effects of traditional perfluorinated and polyfluorinated substances (PFASs) exposure have been extensively explored, research on novel PFASs remains limited, and there is a lack of data regarding their placental transfer and fetal impact. Herein, we aimed to examine maternal and fetal PFASs exposure levels, placental transfer efficiency (TTE), and the consequences of prenatal exposure on birth weight. The study included 214 mother-child pairs recruited in Wuxi birth cohort from 2019 to 2021. Twenty-three PFASs were quantified in maternal serum during the second trimester and umbilical serum during delivery. Median concentrations of ∑23PFASs in maternal and cord sera were 9.34 and 6.88 ng/mL, respectively. The novel alternatives exhibited elevated levels of maternal and fetal exposure, such as perfluorovaleric acid (PFPeA, 2.00 ng/mL and 1.66 ng/mL, respectively) and perfluorohexane sulfonate (PFHxS, 1.77 and 1.14 ng/mL, respectively). With increasing carbon chain length, the TTE of perfluorocarbonic acid (PFCAs) displayed a pattern of initially decreasing before subsequently increasing, with novel alternatives exhibiting a relatively high TTE. Multiple linear regression showed that exposure to perfluorobutane sulfonate (PFBS) and PFPeA in cord serum positively correlated with the birth weight of female infants (β = 231.04 g, 95% confidence interval [CI]: 21.73-440.36; β = 121.26 g, 95% CI: 29.51-213.00). No nonlinear relationship was observed between cord serum PFASs and birth weight. The weighted quantile sum (WQS) regression analysis has reaffirmed that PFPeA and PFBS were predominant contributors to the positive correlation observed between the mixture of PFASs and birth weight. Our findings suggest that novel PFASs may exhibit a heightened susceptibility for transplacental transfer and that exposure to PFBS and PFPeA during pregnancy could be linked to increased birth weight.

Examining a decade-long trend in exposure to per- and polyfluoroalkyl substances and their correlation with lipid profiles: Insights from a prospective cohort study on the young Taiwanese population

Per- and polyfluoroalkyl substances (PFAS) are artificial chemicals extensively utilized in everyday products, and numerous cross-sectional epidemiological studies consistently link PFAS exposure with lipid profiles across diverse populations and age groups. In longitudinal studies, the findings also indicate a positive correlation between PFAS and lipid profiles; however, this association remains unexplored in adolescents and young adults. Notably, previous research has predominantly focused on conventional lipid biomarkers, with limited exploration of the relationship between PFAS and diverse lipoprotein subfractions. Furthermore, there is a lack of comprehensive investigation into the temporal trends in PFAS concentrations in Taiwan. To address this research gap, we conducted a prospective study following 592 adolescents and young adults (12-30 years old at enrollment) from the YOung TAiwanese Cohort (YOTA) over a duration of 10 years. During the follow-up period, we measured 11 types of PFAS and various lipid profile biomarkers (low-density lipoprotein cholesterol (LDL-C), small dense LDL-C (sdLDL-C), low-density lipoprotein triglyceride (LDL-TG), high-density lipoprotein cholesterol (HDL-C), HDL3-C, lipoprotein(a), triglyceride). Our results revealed a general decline in PFAS concentrations in the study population. Regarding the correlation between the average levels (averaged across the initial and second tracking periods) of PFAS and lipid profiles (during the second tracking period), we observed positive correlations with total cholesterol and LDL-C for perfluorononanoic acid (PFNA), perfluoroundecanoic acid (PFUdA), perfluorododecanoic acid (PFDoA), N-methylperfluorooctane sulfonamide acetic acid (N-MeFOSAA), and the sum of PFAS (sum of the 11 kinds of PFAS). Additionally, average levels of PFUdA, N-MeFOSAA, and the sum of PFAS exhibited positive associations with sdLDL-C. This study unveiled an overall decrease in PFAS concentrations and underscores a potential link between PFAS exposure and adverse changes in lipid profiles among young populations, emphasizing the need for further exploration into the mechanisms of PFAS on lipid metabolism and atherosclerosis.

Changes in bile acid subtypes and improvements in lipid metabolism and atherosclerotic cardiovascular disease risk: the Preventing Overweight Using Novel Dietary Strategies (POUNDS Lost) trial

BACKGROUND

Distinct circulating bile acid (BA) subtypes may play roles in regulating lipid homeostasis and atherosclerosis.

OBJECTIVES

We investigated whether changes in circulating BA subtypes induced by weight-loss dietary interventions were associated with improved lipid profiles and atherosclerotic cardiovascular disease (ASCVD) risk estimates.

METHODS

This study included adults with overweight or obesity (n = 536) who participated in a randomized weight-loss dietary intervention trial. Circulating primary and secondary unconjugated BAs and their taurine-/glycine-conjugates were measured at baseline and 6 mo after the weight-loss diet intervention. The ASCVD risk estimates were calculated using the validated equations.

RESULTS

At baseline, higher concentrations of specific BA subtypes were related to higher concentrations of atherogenic very low-density lipoprotein lipid subtypes and ASCVD risk estimates. Weight-loss diet-induced decreases in primary BAs were related to larger reductions in triglycerides and total cholesterol [every 1 standard deviation (SD) decrease of glycocholate, glycochenodeoxycholate, or taurochenodeoxycholate was related to β (standard error) -3.3 (1.3), -3.4 (1.3), or -3.8 (1.3) mg/dL, respectively; PFDR < 0.05 for all]. Greater decreases in specific secondary BA subtypes were also associated with improved lipid metabolism at 6 mo; there was β -4.0 (1.1) mg/dL per 1-SD decrease of glycoursodeoxycholate (PFDR =0.003) for changes in low-density lipoprotein cholesterol. We found significant interactions (P-interaction < 0.05) between dietary fat intake and changes in BA subtypes on changes in ASCVD risk estimates; decreases in primary and secondary BAs (such as conjugated cholate or deoxycholate) were significantly associated with improved ASCVD risk after consuming a high-fat diet, but not after consuming a low-fat diet.

CONCLUSIONS

Decreases in distinct BA subtypes were associated with improved lipid profiles and ASCVD risk estimates, highlighting the importance of changes in circulating BA subtypes as significant factors linked to improved lipid metabolism and ASCVD risk estimates in response to weight-loss dietary interventions. Habitual dietary fat intake may modify the associations of changes in BAs with ASCVD risk. This trial was registered at clinicaltrials.gov as NCT00072995.

Perfluoroalkyl/Polyfluoroalkyl Substances: Links to Cardiovascular Disease Risk

Conservative estimates by the World Health Organization suggest that at least a quarter of global cardiovascular diseases are attributable to environmental exposures. Associations between air pollution and cardiovascular risk have garnered the most headlines and are strong, but less attention has been paid to other omnipresent toxicants in our ecosystem. Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are man-made chemicals that are extensively used in industrial and consumer products worldwide and in aqueous film-forming foam utilized in firefighting. As such, our exposure to PFAS is essentially ubiquitous. Given the long half-lives of these degradation-resistant chemicals, virtually, all people are carrying a body burden of PFAS. Health concerns related to PFAS are growing such that the National Academies of Sciences, Engineering and Medicine has recommended standards for clinical follow-up of individuals with high PFAS blood levels, including prioritizing screening for dyslipidemia. The link between PFAS and dyslipidemia has been extensively investigated, and evidence for associations is compelling. However, dyslipidemia is not the only cardiovascular risk factor with which PFAS is associated. Here, we review the epidemiological evidence for links between PFAS of concern identified by the National Academies of Sciences, Engineering and Medicine and risk factors for cardiovascular disease, including overweight/obesity, glucose intolerance, hypertension, dyslipidemia, and hyperuricemia. Moreover, we review the potential connections of PFAS with vascular disease and atherosclerosis. While observational data support associations between the National Academies of Sciences, Engineering and Medicine PFAS and selected cardiac risk factors, additional research is needed to establish causation and better understand how exposure to PFAS leads to the development of these conditions.

All-cause, cardiovascular disease and cancer mortality in the population of a large Italian area contaminated by perfluoroalkyl and polyfluoroalkyl substances (1980-2018)

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are associated with many adverse health conditions. Among the main effects is carcinogenicity in humans, which deserves to be further clarified. An evident association has been reported for kidney cancer and testicular cancer. In 2013, a large episode of surface, ground and drinking water contamination with PFAS was uncovered in three provinces of the Veneto Region (northern Italy) involving 30 municipalities and a population of about 150,000. We report on the temporal evolution of all-cause mortality and selected cause-specific mortality by calendar period and birth cohort in the local population between 1980 and 2018.

METHODS

The Italian National Institute of Health pre-processed and made available anonymous data from the Italian National Institute of Statistics death certificate archives for residents of the provinces of Vicenza, Padua and Verona (males, n = 29,629; females, n = 29,518) who died between 1980 and 2018. Calendar period analysis was done by calculating standardised mortality ratios using the total population of the three provinces in the same calendar period as reference. The birth cohort analysis was performed using 20-84 years cumulative standardised mortality ratios. Exposure was defined as being resident in one of the 30 municipalities of the Red area, where the aqueduct supplying drinking water was fed by the contaminated groundwater.

RESULTS

During the 34 years between 1985 (assumed as beginning date of water contamination) and 2018 (last year of availability of cause-specific mortality data), in the resident population of the Red area we observed 51,621 deaths vs. 47,731 expected (age- and sex-SMR: 108; 90% CI: 107-109). We found evidence of raised mortality from cardiovascular disease (in particular, heart diseases and ischemic heart disease) and malignant neoplastic diseases, including kidney cancer and testicular cancer.

CONCLUSIONS

For the first time, an association of PFAS exposure with mortality from cardiovascular disease was formally demonstrated. The evidence regarding kidney cancer and testicular cancer is consistent with previously reported data.

Exploring the impact of prenatal perfluoroalkyl and polyfluoroalkyl substances exposure on blood pressure in early childhood: A longitudinal analysis

Previous research investigating the correlation between prenatal exposure to per- and polyfluoroalkyl substances (PFAS) and subsequent blood pressure (BP) in offspring has yielded limited and contradictory findings. This study was conducted to investigate the potential relationship between maternal PFAS levels during pregnancy and subsequent BP in early childhood. A total of 129 expectant mothers from the Shanghai Birth Cohort were included in the study. Using high-performance liquid chromatography/tandem mass spectrometry, we measured ten PFAS compounds in maternal plasma throughout the pregnancy. When the children reached the age of 4, we examined their systolic BP (SBP) and diastolic BP (DBP), along with mean arterial pressure (MAP) and pulse pressure (PP). Data interpretation employed multiple linear and logistic regression models, complemented by Bayesian kernel machine regression (BKMR).We found that the majority of PFAS concentrations remained stable during pregnancy. The linear and BKMR models indicated a positive relationship between the PFAS mixture in maternal plasma and offspring's DBP and MAP, with perfluorohexanesulphonic acid (PFHxS) having the most significant influence (PFHxS and DBP [first trimester:β=3.03, 95%CI: (1.01,5.05); second trimester: β=2.35, 95%CI: (0.94,3.75); third trimester: β=2.57, 95%CI:(0.80,4.34)]; MAP [first trimester:β=2.55, 95%CI: (0.64,4.45); second trimester: β=2.28, 95%CI: (0.95,3.61); third trimester: β=2.35, 95%CI:(0.68,4.01)]). Logistic regression highlighted an increased risk of prehypertension and hypertension in offspring with higher maternal PFHxS concentrations during all three trimesters [first trimester: OR=2.53, 95%CI:(1.11,5.79), second trimester: OR=2.05, 95%CI:(1.11,3.78), third trimester: OR=3.08, 95%CI:(1.40,6.79)]. A positive correlation was identified between the half-lives of PFAS and the odds ratio (OR) of prehypertension and hypertension in childhood (β=0.139, P=0.010). In conclusion, this research found maternal plasma PFAS concentrations to be positively associated with BP in offspring, with PFHxS showing the most significant influence. This correlation remained consistent throughout pregnancy, and this effect was proportional to the half-lives of PFAS.

Chemical contaminants in blood and their implications in chronic diseases

Artificial chemical products are widely used and ubiquitous worldwide and pose a threat to the environment and human health. Accumulating epidemiological and toxicological evidence has elucidated the contributions of environmental chemical contaminants to the incidence and development of chronic diseases that have a negative impact on quality of life or may be life-threatening. However, the pathways of exposure to these chemicals and their involvements in chronic diseases remain unclear. We comprehensively reviewed the research progress on the exposure risks of humans to environmental contaminants, their body burden as indicated by blood monitoring, and the correlation of blood chemical contaminants with chronic diseases. After entering the human body through various routes of exposure, environmental contaminants are transported to target organs through blood circulation. The application of the modern analytical techniques based on human plasma or serum specimens is promising for determining the body burden of environmental contaminants, including legacy persistent organic pollutants, emerging pollutants, and inorganic elements. Furthermore, their body burden, as indicated by blood monitoring correlates with the incidence and development of metabolic syndromes, cancers, chronic nervous system diseases, cardiovascular diseases, and reproductive disorders. On this basis, we highlight the urgent need for further research on environmental pollution causing health problems in humans.

Overall and individual associations between per- and polyfluoroalkyl substances and liver function indices and the metabolic mechanism

Per- and polyfluoroalkyl substances (PFAS) can disrupt liver homeostasis. Studies have shown that a single exposure to PFAS may provoke abnormal liver function; however, few studies have investigated the overall effect of PFAS mixtures. We aimed to investigate associations between exposure to PFAS mixtures and liver function indices and explore the relevant mechanisms. This study included 278 adult males from Guangzhou, China. Serum metabolite profiles were analyzed using untargeted metabolomics. We applied weighted quantile sum (WQS) regression as well as Bayesian kernel machine regression (BKMR) to analyze the association of nine PFAS mixtures with 14 liver function indices. PFAS mixtures were positively associated with apolipoprotein B (APOB) and gamma-glutamyltransferase (GGT) and negatively associated with direct bilirubin (DBIL) and total bilirubin (TBIL) in both the WQS and BKMR analyses. In addition, Spearman's correlation test showed individual PFAS correlated with APOB, GGT, TBIL, and DBIL, while there's little correlation between individual PFAS and other liver function indices. In linear regression analysis, PFHxS, PFOS, PFHpS, PFNA, PFDA, and PFUdA were associated with APOB; PFOA, PFDA, PFOS, PFNA, and PFUdA were associated with GGT. Subsequently, a metabolome-wide association study and mediation analysis were combined to explore metabolites that mediate these associations. The mechanisms linking PFAS to APOB and GGT are mainly related with amino acid and glycerophospholipid metabolism. High-dimensional mediation analysis showed that glycerophospholipids are the main markers of the association between PFAS and APOB, and that (R)-dihydromaleimide, Ile Leu, (R)-(+)-2-pyrrolidone-5-carboxylic acid, and L-glutamate are the main markers of the association between PFAS and GGT. In summary, overall associations between PFAS and specific indices of liver function were found using two statistical methods; the metabolic pathways and markers identified here may serve to prompt more detailed study in animal-based systems, as well as a similar detailed analysis in other populations.

(-)-Epigallocatechin-3-Gallate Reduces Perfluorodecanoic Acid-Exacerbated Adiposity and Hepatic Lipid Accumulation in High-Fat Diet-Fed Male C57BL/6J Mice

Perfluorodecanoic acid (PFDA), an enduring and harmful organic pollutant, is widely employed in diverse food-related sectors. Our previous studies have provided evidence that PFDA has the potential to facilitate obesity and hepatic fat accumulation induced by high-fat diet (HFD) intake. Epigallocatechin-3-gallate (EGCG), a polyphenol found in green tea, has been suggested to possess potential preventive effects against metabolic abnormalities and fatty liver. The purpose of this research was to investigate the effects of EGCG on PFDA-exacerbated adiposity and hepatic lipid accumulation in HFD-fed mice. The results showed that EGCG reduced body weight gain; tissue and organ weights; blood glucose, serum insulin, HOMA-IR, leptin, and lipid parameters; serum inflammatory cytokines (IL-1β, IL-18, IL-6, and TNF-α); and hepatic lipid accumulation in PFDA-exposed mice fed an HFD. Further work showed that EGCG improved liver function and glucose homeostasis in mice fed an HFD and co-exposed to PFDA. The elevated hepatic mRNA levels of SREBP-1 and associated lipogenic genes, NLRP3, and caspase-1 in PFDA-exposed mice fed an HFD were significantly decreased by EGCG. Our work provides evidence for the potential anti-obesity effect of EGCG on co-exposure to HFD and PFDA and may call for further research on the bioactivity of EGCG to attenuate the endocrine disruption effects of long-term exposure to pollutants.

Perfluoroalkyl substances (PFAS) and lead (Pb) as "cardiovascular disruptors" in 9-11-year-old children living in Syracuse, New York, United States

OBJECTIVE

Per- and polyfluoro-alkyl substances (PFAS) and lead (Pb) are ubiquitous environmental toxicants with apparent impact on cardiovascular disease (CVD) risk. As one possible mechanism for this increased risk, we have previously demonstrated an association between Pb exposure and heightened cardiovascular reactivity to acute psychological stress, a CVD risk factor. The present study expands this approach and considers both PFAS and Pb exposures (and the possible interaction).

METHODS

We assessed 14 serum PFAS and whole blood Pb concentrations in a sample of 9-11 year-old children (N = 291; 43.2% White, 56.8% Black; 53.5% female). We measured cardiovascular functioning at rest and during psychological stress as well as multiple indicators of subclinical CVD including resting blood pressure (BP), carotid-femoral pulse wave velocity (cfPWV), carotid intima-media thickness (cIMT), and left ventricular mass (LVM). Data analysis included general linear modeling as well as a non-parametric approach to study metal mixtures, specifically Bayesian Kernel Machine Regression (BKMR).

RESULTS

Significant interactions between different PFAS and with Pb suggest the importance of considering toxicant mixtures when assessing potential disruption of the cardiovascular system. The pattern of findings suggests that greater "vascular reactivity" (elevated BP and vascular resistance during acute psychological stress) was associated with higher concentrations of perfluorononanoic acid (PFNA), perfluorohexane sulfonate (PFHxS), and Pb, but only when perfluorooctanoic acid (PFOA) was concurrently elevated. With respect to subclinical outcomes, increasing perfluorodecanoic acid (PFDA) was associated with greater cIMT (β = 0.21, p = 0.010).

CONCLUSION

To our knowledge this is the first study to consider how PFAS exposures might affect cardiovascular functioning and subclinical disease. Although a complex pattern of associations emerged, it does appear that PFAS and Pb can be classified as "cardiovascular disruptors" in children. Further research is needed to replicate these novel findings and determine whether these disruptions produce future cardiovascular disease.

Association of per- and polyfluoroalkyl substances with hepatic steatosis and metabolic dysfunction-associated fatty liver disease among patients with acute coronary syndrome

Etiology of hepatic steatosis and metabolic dysfunction-associated fatty liver disease (MAFLD) among acute coronary syndrome (ACS) remains unclear. Existing studies suggested the potential role of per- and polyfluoroalkyl substances (PFAS) in comorbidity of hepatic steatosis among ACS patients. Therefore, we conducted a cross-sectional study based on the ACS inpatients to assess the associations of plasma PFAS congeners and mixtures with hepatic steatosis and MAFLD. This study included 546 newly diagnosed ACS patients. Twelve PFAS were quantified using ultra-high-performance liquid chromatography-tandem mass spectrometry. Hepatic steatosis was defined by hepatic steatosis index (HSI). MAFLD was defined as the combination of hepatic steatosis based on the risk factor calculation with metabolic abnormalities. Generalized linear model was used to examine the associations of PFAS congeners with HSI and MAFLD. Adaptive elastic net (AENET) was further used for PFAS congeners selection. Mixture effects were also assessed with Bayesian kernel machine regression model (BKMR). Congeners analysis observed significant greater percent change of HSI for each doubling in PFOS (1.82%, 95% CI: 0.87%, 2.77%), PFHxS (1.17%, 95% CI: 0.46%, 1.89%) and total PFAS (1.84%, 95% CI: 0.56%, 3.14%). Moreover, each doubling in PFOS (OR=1.42, 95% CI: 1.13, 1.81), PFHxS (OR=1.31, 95% CI: 1.09, 1.59) and total PFAS (OR=1.43, 95% CI: 1.06, 1.94) was associated with increased risk of MAFLD. In AENET regression, only PFOS presented significant positive associations with HSI. Mixture analysis indicated significant positive associations between PFAS mixtures and HSI. This is the first study to demonstrate associations of PFAS congeners and mixtures with hepatic steatosis and MAFLD among ACS patients, which provides hypothesis into the mechanisms behind comorbidity of hepatic steatosis among ACS patients, as well as tertiary prevention of ACS.

Perfluorohexanesulfonic acid (PFHxS) induces oxidative stress and causes developmental toxicities in zebrafish embryos

Perfluorohexanesulfonic acid (PFHxS) is a short-chain perfluoroalkyl substance widely used to replace the banned perfluorooctanesulfonic acid (PFOS) in different industrial and household products. It has currently been identified in the environment and human bodies; nonetheless, the possible toxicities are not well-known. Zebrafish have been used as a toxicant screening model due to their fast and transparent developmental processes. In this study, zebrafish embryos were exposed to PFHxS for five days, and various experiments were performed to monitor the developmental and cellular processes. Liquid chromatography-mass spectrometry (LC/MS) analysis confirmed that PFHxS was absorbed and accumulated in the zebrafish embryos. We reported that 2.5 µM or higher PFHxS exposure induced phenotypic abnormalities, marked by developmental delay in the mid-hind brain boundary and yolk sac edema. Additionally, larvae exposed to PFHxS displayed facial malformation due to the reduction of neural crest cell expression. RNA sequencing analysis further identified 4643 differentiated expressed transcripts in 5 µM PFHxS-exposed 5-days post fertilization (5-dpf) larvae. Bioinformatics analysis revealed that glucose metabolism, lipid metabolism, as well as oxidative stress were enriched in the PFHxS-exposed larvae. To validate these findings, a series of biological experiments were conducted. PFHxS exposure led to a nearly 4-fold increase in reactive oxygen species, possibly due to hyperglycemia and impaired glutathione balance. The Oil Red O' staining and qPCR analysis strengthens the notions that lipid metabolism was disrupted, leading to lipid accumulation, lipid peroxidation, and malondialdehyde formation. All these alterations ultimately affected cell cycle events, resulting in S and G2/M cell cycle arrest. In conclusion, our study demonstrated that PFHxS could accumulate and induce various developmental toxicities in aquatic life, and such data might assist the government to accelerate the regulatory policy on PFHxS usage.

Exposure to perfluoroalkyl and polyfluoroalkyl substances and risk of stroke in adults: a meta-analysis

INTRODUCTION

Evidence of the adverse metabolic health effects of perfluoroalkyl and polyfluoroalkyl substances (PFAS) is increasing. However, the impact of PFAS on cardiovascular diseases remains controversial. This meta-analysis aimed to analyze the impact of PFAS on the stroke risk.

CONTENT

Databases were searched for studies published up to November 1, 2022, which report the association between stroke and exposure to at least one of four main PFAS (perfluorooctanoic acid [PFOA], perfluorooctanesulfonic acid [PFOS], perfluorononanoic acid [PFNA], and perfluorohexane sulfonic acid [PFHxS]). Data extraction and quality assessment were performed according to the Newcastle-Ottawa scale.

SUMMARY AND OUTLOOK

Four studies were included in this systematic review. Multivariate adjusted odds ratios (ORs) for incident stroke per 1-log unit increment in each serum PFAS were combined in the meta-analysis. The risk of development of stroke was not significantly associated with PFOA, PFOS, or PFNA exposure (PFOA: pooled odds ratio [OR]=1.001, 95 % confidence interval [CI]=0.975-1.028, p=0.934; PFOS: pooled OR=0.994, 95 % CI=0.972-1.017, p=0.601; PFNA: pooled OR=1.016, 95 % CI=0.920-1.123, p=0.752), whereas a moderately lower risk was associated with PFHxS exposure without statistical significance (pooled OR=0.953, 95 % CI=0.908-1.001, p=0.054). PFOA, PFOS, and PFNA exposure showed a neutral association, while PFHxS showed a possible inverse association with the risk of stroke. Therefore, this finding should be interpreted with caution. Further prospective observational studies with PFAS mixture analyses are warranted.

Associations of perfluoroalkyl substances (PFAS) with lipid and lipoprotein profiles

BACKGROUND

Perfluoroalkyl substances (PFAS) are man-made chemicals with unique properties that are widely distributed in humans and the environment. Recent studies suggest that PFAS are involved in cholesterol metabolism, however, the mechanisms underlying the associations are poorly understood.

OBJECTIVE

We aimed to evaluate associations of plasma PFAS with detailed lipid and lipoprotein subfractions in an adult population of men and women.

METHODS

We measured concentrations of cholesterol and triglycerides in lipoprotein subfractions, apolipoprotein subclasses, as well as fatty acid and different phospholipid measures, using serum proton nuclear magnetic resonance (1H-NMR), and four plasma PFAS using liquid chromatography-mass spectrometry (UHPLC-MS/MS). Measurements were available for 493 participants (all aged 50 years, 50% female). Multivariable linear regression was used to estimate the association of four PFAS with 43 different 1H-NMR measures, with adjustment for body mass index (BMI), smoking, education, and physical activity.

RESULTS

We found that perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDA), but not perfluorohexanesulfonate (PFHxS), concentrations were consistently positively associated with concentrations of cholesterol in lipoprotein subfractions, apolipoproteins, as well as composite fatty acid- and phospholipid profiles. The most consistent associations were found for the relationship of PFAS with total cholesterol in intermediate-density lipoprotein (IDL), across all low-density lipoprotein (LDL) subfractions and small high-density lipoprotein (HDL). Moreover, we found weak to null evidence for an association of any of the measured 13 triglyceride lipoprotein subfractions with PFAS.

CONCLUSIONS

Our results suggest that plasma PFAS concentrations are associated with cholesterol in small HDL, IDL and all LDL subfractions, as well as apolipoproteins and composite fatty acid and phospholipid profiles but to a lesser extent with triglycerides in lipoproteins. Our findings draw attention to the need for more detailed measurements of lipids across various lipoprotein subfractions and subclasses in assessing the role of PFAS in lipid metabolism.

IMPACT

By performing an in-depth characterization of circulating cholesterol and triglycerides in lipoprotein subfractions, apolipoprotein, fatty acid, and phospholipid concentrations, this study has expanded upon the limited literature available on the associations of plasma PFAS concentrations beyond clinical routine laboratory testing for lipids.

PFAS Exposures and the Human Metabolome: A Systematic Review of Epidemiological Studies

Purpose of Review

There is a growing interest in understanding the health effects of exposure to per- and polyfluoroalkyl substances (PFAS) through the study of the human metabolome. In this systematic review, we aimed to identify consistent findings between PFAS and metabolomic signatures. We conducted a search matching specific keywords that was independently reviewed by two authors on two databases (EMBASE and PubMed) from their inception through July 19, 2022 following PRISMA guidelines.

Recent Findings

We identified a total of 28 eligible observational studies that evaluated the associations between 31 different PFAS exposures and metabolomics in humans. The most common exposure evaluated was legacy long-chain PFAS. Population sample sizes ranged from 40 to 1,105 participants at different stages across the lifespan. A total of 19 studies used a non-targeted metabolomics approach, 7 used targeted approaches, and 2 included both. The majority of studies were cross-sectional (n = 25), including four with prospective analyses of PFAS measured prior to metabolomics.

Summary

Most frequently reported associations across studies were observed between PFAS and amino acids, fatty acids, glycerophospholipids, glycerolipids, phosphosphingolipids, bile acids, ceramides, purines, and acylcarnitines. Corresponding metabolic pathways were also altered, including lipid, amino acid, carbohydrate, nucleotide, energy metabolism, glycan biosynthesis and metabolism, and metabolism of cofactors and vitamins. We found consistent evidence across studies indicating PFAS-induced alterations in lipid and amino acid metabolites, which may be involved in energy and cell membrane disruption.

DNA Methylation Near CPT1A and Changes in Triglyceride-rich Lipoproteins in Response to Weight-loss Diet Interventions

CONTEXT

Carnitine palmitoyltransferase-1A, encoded by the CPT1A gene, plays a key role in the oxidation of long-chain fatty acids in the mitochondria and may be important in triglyceride metabolism. Previous work has shown that high fat intake was negatively associated with CPT1A methylation and positively associated with CPT1A expression.

OBJECTIVE

We aim to investigate the association of DNA methylation (DNAm) at the CPT1A gene with reductions in triglycerides and triglyceride-rich lipoproteins (TRLs) in response to weight-loss diet interventions.

METHODS

The current study included 538 White participants, who were randomly assigned to 1 of 4 diets varying in macronutrient components. We defined the regional DNAm at CPT1A as the average methylation level over CpGs within 500 bp of the 3 triglyceride-related DNAm sites.

RESULTS

Dietary fat intake significantly modified the association between baseline DNAm at CPT1A and 2-year changes in total plasma triglycerides, independent of concurrent weight loss. Among participants assigned to a low-fat diet, a higher regional DNAm level at CPT1A was associated with a greater reduction in total plasma triglycerides at 2 years (P = .01), compared with those assigned to a high-fat diet (P = .64) (P interaction = .018). Further investigation on lipids and apolipoproteins in very low-density lipoprotein (VLDL) revealed similar interaction patterns for 2-year changes in VLDL-triglycerides, VLDL-cholesterol, and VLDL-apolipoprotein B (P interaction = .009, .002, and .016, respectively), but not for VLDL-apoC-III (P interaction = .36).

CONCLUSION

Participants with a higher regional DNAm level at CPT1A benefit more in long-term improvement in triglycerides, particularly in the TRLs and related apolipoproteins when consuming a low-fat weight-loss diet.

Perfluorodecanoic acid promotes high-fat diet-triggered adiposity and hepatic lipid accumulation by modulating the NLRP3/caspase-1 pathway in male C57BL/6J mice

Perfluorodecanoic acid (PFDA), a chemical contaminant, may casue became obesity, which makes it a public health concern. In this study, we investigated the effects of PFDA on adiposity development and hepatic lipid accumulation in mice fed with a high-fat diet (HFD). Animals were assigned to two diet treatments (low-fat and high-fat); and PFDA was administered through drinking water for 12 weeks. The contaminant promoted body weight gain and adiposity in HFD-fed mice. Moreover, HFD-fed mice exposed to PFDA had impaired glucose metabolism, inflammation and hepatic lipid accumulation compared to mice fed HFD alone. PFDA activated the expression of hepatic NLRP3 and caspase-1, and induced that of SREBP-1c expression in the liver of HFD-fed mice. PFDA exposure in HFD-fed mice significantly inhibited hepatic AMPK expression than animals fed HFD without PFDA exposure. Furthermore, MCC950, an NLRP3 inhibitor, suppressed the upregulation of NLRP3 and caspase-1 expression, and inhibited the expression of SREBP-1c and the accumulation of hepatic lipid in mice exposed to PFDA. Thus, PFDA may enhance HFD-induced adiposity and hepatic lipid accumulation through the NLRP3/caspase-1 pathway. This contaminant may be a key risk factor for obesity development in individuals consuming high-fat foods, particularly Western diet.

First Investigation of the Physiological Distribution of Legacy and Emerging Perfluoroalkyl Substances in Raw Bovine Milk According to the Component Fraction

Bovine milk is a pillar of the human diet and plays a key role in the nutrition of infants. Perfluoroalkyl substances (PFASs) are well-recognized highly stable organic compounds that are able to pollute ecosystems persistently and threaten both human and animal health. The study aimed to analyze the distribution of 14 PFASs within the milk matrix by comparing their content in whole milk, and its skimmed and creamed fractions. Raw milk samples were individually collected from 23 healthy cows (10 primiparous and 13 multiparous) reared on a farm in Northern Italy not surrounded by known point sources of PFASs. Each sample was fractioned in whole, skim, and cream components to undergo PFAS analysis using liquid chromatography-high-resolution mass spectrometry. All samples contained at least one PFAS, with perfluorobutanoic acid (PFBA) being the primary contaminant in all three fractions, followed by perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). PFOS was shown to be significantly (p < 0.001) more concentrated in cream than in raw and skimmed milk. Multiparous cows showed a higher frequency of positive samples in all analyzed fractions. Further research is necessary to assess the risk of dairy diets and high-fat dairy products and to investigate the toxicological effects of PFASs on cattle, even in environments without known PFAS sources.

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.

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.

Per- and Polyfluoroalkyl Substances and Outcomes Related to Metabolic Syndrome: A Review of the Literature and Current Recommendations for Clinicians

Per- and polyfluoroalkyl substances (PFAS) are a class of toxic, ubiquitous, anthropogenic chemicals known to bioaccumulate in humans. Substantial concern exists regarding the human health effects of PFAS, particularly metabolic syndrome (MetS), a precursor to cardiovascular disease, the leading cause of mortality worldwide. This narrative review provides an overview of the PFAS literature on 4 specific components of MetS: insulin resistance/glucose dysregulation, central adiposity, dyslipidemia, and blood pressure. We focus on prospective cohort studies as these provide the best body of evidence compared to other study designs. Available evidence suggests potential associations between some PFAS and type-2 diabetes in adults, dyslipidemia in children and adults, and blood pressure in adults. Additionally, some studies found that sex and physical activity may modify these relationships. Future studies should consider modification by sex and lifestyle factors (e.g., diet and physical activity), as well quantifying the impact of PFAS mixtures on MetS features and related clinical disease. Finally, clinicians can follow recently developed clinical guidance to screen for PFAS exposure in patients, measure PFAS levels, conduct additional clinical care based on PFAS levels, and advise on PFAS exposure reduction.

Effect of lifestyle-based lipid lowering interventions on the relationship between circulating levels of per-and polyfluoroalkyl substances and serum cholesterol

Exposure to certain per-and polyfluoroalkyl substances (PFAS) has been shown to be positively associated with total and/or low-density lipoprotein cholesterol. Examining this association in lipid lowering interventions may provide additional evidence linking PFAS to cardiovascular risk. We examined the relationship of 6 PFAS with cholesterol in a 6-month lifestyle-based intervention. We quantitated PFAS in 350 individuals at baseline and post intervention and examined associations of PFAS with cholesterol before and after intervention. Food frequency questionnaires and GIS analyses were used to investigate PFAS hotspots and possible exposure routes. Cholesterol significantly decreased following intervention and in parallel, PFOS, PFOA, PFHxS, and PFHpA significantly decreased. PFOS was positively correlated with total cholesterol only post-intervention. We observed that PFOS was distributed among both non-albumin and albumin lipoprotein fractions pre-intervention, but entirely in albumin fraction post-intervention. Our results indicate that lipid-lowering via lifestyle modification may impact on circulating levels or distribution of PFAS.

Combinatorial pathway disruption is a powerful approach to delineate metabolic impacts of endocrine disruptors

The prevalence of metabolic diseases, such as obesity, diabetes, metabolic syndrome and chronic liver diseases among others, has been rising for several years. Epidemiology and mechanistic (in vivo, in vitro and in silico) toxicology have recently provided compelling evidence implicating the chemical environment in the pathogenesis of these diseases. In this review, we will describe the biological processes that contribute to the development of metabolic diseases targeted by metabolic disruptors, and will propose an integrated pathophysiological vision of their effects on several organs. With regard to these pathomechanisms, we will discuss the needs, and the stakes of evolving the testing and assessment of endocrine disruptors to improve the prevention and management of metabolic diseases that have become a global epidemic since the end of last century.

Perfluoroalkyl substances and lipid concentrations in the blood: A systematic review of epidemiological studies

BACKGROUND

Perfluoroalkyl substances (PFAS) are widely used synthetic aliphatic compounds. This systematic review aims to assess PFAS associations with low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), total cholesterol (TC) and total triglyceride (TG) concentrations in human populations.

METHOD

We systematically searched four online databases, PubMed, Scopus, Embase, and Cochrane Library for relevant peer-reviewed English language articles published until July 2021. Additional relevant articles identified were also included in the search results. We categorised populations into adults (≥18 years old) and children. Primary findings were the associations between PFAS concentrations and LDL, HDL, TC, and TG concentrations in the serum, plasma, or whole blood; secondary findings were the associations between PFAS concentrations and the odds of lipid-related health outcomes. Quantitative synthesis was done by vote counting of the effect directions between concentrations of PFAS and lipids/health outcomes, repeated on articles with sample size >1000. Sign tests were performed to assess the statistical significance of the differences between positive and negative associations. Sensitivity analysis was performed by separating out articles with populations having high concentrations of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). Quality was assessed with the STROBE checklist and NHBLI Study Quality Assessment Tool.

RESULTS

A total of 58 articles were included for review. There was evidence that PFAS exposure is associated with higher concentrations of LDL, HDL, and TC, particularly for PFOA-LDL, PFOA-TC, PFOS-TC, and PFNA-LDL. Associations between PFAS and TG tended to be negative, especially for perfluoroundecanoic acid (PFUnDA). Associations between PFAS concentration and the odds of secondary outcomes generally supported a positive association between PFAS and cholesterol concentrations.

CONCLUSION

We found evidence of associations between the concentrations of some PFAS-lipid pairs in human populations. Future research should be conducted on the less well-studied PFAS to explore their effects on human health and in regions where such studies are currently lacking. (300 words).

Physical activity modifies the relation between gestational perfluorooctanoic acid exposure and adolescent cardiometabolic risk

OBJECTIVE

Exposure to per- and polyfluoroalkyl substances (PFAS) - endocrine disrupting chemicals - may increase cardiometabolic risk. We evaluated whether adolescent lifestyle factors modified associations between gestational PFAS exposure and cardiometabolic risk using a prospective cohort study.

METHODS

In 166 mother-child pairs (HOME Study), we measured concentrations of four PFAS in maternal serum collected during pregnancy. When children were age 12 years, we calculated cardiometabolic risk scores from visceral adiposity area, blood pressure, and fasting serum biomarkers. We assessed adolescent physical activity and Healthy Eating Index scores using the Physical Activity Questionnaire for Older Children (PAQ-C), actigraphy, and 24-h diet recalls. Using multivariable linear regression and weighted quantile sum regression, we examined whether physical activity or diet modified covariate-adjusted associations of PFAS and their mixture with cardiometabolic risk scores.

RESULTS

Physical activity modified associations between perfluorooctanoic acid (PFOA) and cardiometabolic risk scores. Each doubling of PFOA was associated with worse cardiometabolic risk scores among children with PAQ-C scores < median (β:1.4; 95% CI:0.5, 2.2, n = 82), but not among those with PAQ-C scores ≥ median (β: 0.2; 95% CI: 1.2, 0.7, n = 84) (interaction p-value = 0.01). Associations were most prominent for insulin resistance, leptin-adiponectin ratio, and visceral fat area. We observed results suggesting that physical activity modified the association of PFAS mixture with cardiometabolic risk scores, insulin resistance, and visceral fat area (interaction p-values = 0.17, 0.07, and 0.10, respectively); however, the 95% CIs of the interaction terms included the null value. We observed similar, but attenuated patterns for PFOA and actigraphy-based measures of physical activity. Diet did not modify any associations. Physical activity or diet did not modify associations for other PFAS.

CONCLUSIONS

Childhood physical activity modified associations of prenatal serum PFOA concentrations with children's cardiometabolic risk in this cohort, indicating that lifestyle interventions may ameliorate the adverse effects of PFOA exposure.

Integument carotenoid-based colouration reflects contamination to perfluoroalkyl substances, but not mercury, in arctic black-legged kittiwakes

Anthropogenic activities are introducing multiple chemical contaminants into ecosystems that act as stressors for wildlife. Perfluoroalkyl substances (PFAS) and mercury (Hg) are two relevant contaminants that may cause detrimental effects on the fitness of many aquatic organisms. However, there is a lack of information on their impact on the expression of secondary sexual signals that animals use for mate choice. We have explored the correlations between integument carotenoid-based colourations, blood levels of carotenoids, and blood levels of seven PFAS and of total Hg (THg) in 50 adult male black-legged kittiwakes (Rissa tridactyla) from the Norwegian Arctic during the pre-laying period, while controlling for other colouration influencing variables such as testosterone and body condition. Kittiwakes with elevated blood concentrations of PFAS (PFOSlin, PFNA, PFDcA, PFUnA, or PFDoA) had less chromatic but brighter bills, and brighter gape and tongue; PFOSlin was the pollutant with the strongest association with bill colourations. Conversely, plasma testosterone was the only significant correlate of hue and chroma of both gape and tongue, and of hue of the bill. Kittiwakes with higher concentrations of any PFAS, but not of THg, tended to have significantly higher plasma concentrations of the carotenoids astaxanthin, zeaxanthin, lutein, and cryptoxanthin. Our work provides the first correlative evidence that PFAS exposure might interfere with the carotenoid metabolism and the expression of integument carotenoid-based colourations in a free-living bird species. This outcome may be a direct effect of PFAS exposure or be indirectly caused by components of diet that also correlate with elevated PFAS concentrations (e.g., proteins). It also suggests that there might be no additive effect of THg co-exposure with PFAS on the expression of colourations. These results call for further work on the possible interference of PFAS with the expression of colourations used in mate choice.

Lipoprotein profiles associated with exposure to poly- and perfluoroalkyl substances (PFASs) in the EuroMix human biomonitoring study

Exposure to per- and polyfluoroalkyl substances (PFASs) is associated with increased blood cholesterol. Although elevated cholesterol is a well-established risk factor for cardiovascular diseases (CVD), it is not clear whether PFASs affect this risk. Lipoprotein subclasses are emerging biomarkers for disease risk and lipoprotein profiling may provide an insight to physiological implications of PFAS exposure. We explored the association between serum PFAS concentrations and lipoprotein subclasses in a cross-sectional study. We determined the concentrations and lipid composition of the major subclasses of lipoproteins in plasma samples from 127 adult participants of the EuroMix human biomonitoring study by nuclear magnetic resonance (NMR). Serum concentrations of 17 PFASs showed a detection frequency between 30 and 100% and were included in further analyses. We examined the associations between PFAS concentrations and lipoprotein subclasses by linear mixed-effect regression models, adjusted for confounders. In the adjusted models, positive associations were found between several PFASs and cholesterol concentrations in large to medium sized HDL and medium sized LDL particles. We found a 4-12% increase in HDL cholesterol per interquartile range (IQR) increase for several PFASs. In women the associations with PFNA, PFUnDA, PFDoDA and PFOS were significant after adjustment for multiple comparisons. Similar magnitude of change was observed between longer chained PFASs and LDL cholesterol, and a few of these associations reached significance for cholesterol in large to medium LDL particle sizes in women. No significant associations with plasma triglycerides were observed. However, most PFASs tended to be associated with reduction in VLDL (very low-density lipoproteins) particle number and VLDL triglyceride. Findings from this exploratory study, suggest that background PFAS exposures influence particle size distributions and lipid composition of plasma lipoprotein subclasses, and that these effects may be more prominent in women. A two-points lipoprofiling for all subjects indicated both low intra-individual variability and good analytical reproducibility.

Mechanisms Underlying the Impacts of Lipids on the Diverse Bioavailability of Per- and Polyfluoroalkyl Substances in Foods

Food is a major source of human exposure to per- and polyfluoroalkyl substances (PFASs), yet little is known about their bioavailability in food matrices. Here, the relative bioavailability (RBA) of PFASs in foods was determined using an in vivo mouse model. Pork, which had the highest lipid content, exhibited the greatest effect on bioavailability by increasing the RBAs of perfluoroalkyl acids (PFAAs) while reducing those of fluorotelomer phosphate diesters (diPAPs). During intestinal digestion of lipids, the bioaccessibility of PFAAs increased due to their greater partition into the stable mixed micelles. However, diPAPs were more likely to partition into the undigested oil phase due to their strong hydrophobicity. Both in vitro incubation and molecular docking results indicated that the PFAAs exhibited stronger binding affinities with mouse blood chylomicrons (CMs) than with diPAPs. Collectively, both lipid digestion in the intestine and the carrier effect of CMs played important roles in modulating the bioavailability of PFASs in food. More attention should be given to further evaluating the health risks of PFASs associated with the intake of high-lipid foods.

Metabolic Syndrome and Endocrine Disrupting Chemicals: An Overview of Exposure and Health Effects

Increasing prevalence of metabolic syndrome (MetS) is causing a significant health burden among the European population. Current knowledge supports the notion that endocrine-disrupting chemicals (EDCs) interfere with human metabolism and hormonal balance, contributing to the conventionally recognized lifestyle-related MetS risk factors. This review aims to identify epidemiological studies focusing on the association between MetS or its individual components (e.g., obesity, insulin resistance, diabetes, dyslipidemia and hypertension) and eight HBM4EU priority substances (bisphenol A (BPA), per- and polyfluoroalkyl substances (PFASs), phthalates, polycyclic aromatic hydrocarbons (PAHs), pesticides and heavy metals (cadmium, arsenic and mercury)). Thus far, human biomonitoring (HBM) studies have presented evidence supporting the role of EDC exposures on the development of individual MetS components. The strength of the association varies between the components and EDCs. Current evidence on metabolic disturbances and EDCs is still limited and heterogeneous, and mainly represent studies from North America and Asia, highlighting the need for well-conducted and harmonized HBM programmes among the European population. Rigorous and ongoing HBM in combination with health monitoring can help to identify the most concerning EDC exposures, to guide future risk assessment and policy actions.

Changes in gut-microbiota-related metabolites and long-term improvements in lipoprotein subspecies in overweight and obese adults: the POUNDS lost trial

BACKGROUND/OBJECTIVES

Alterations in gut microbiota have been linked to obesity and impaired lipid metabolism. Lipoproteins are heterogeneous, and lipoprotein subspecies containing apolipoprotein C-III (apoCIII) have adverse associations with obesity and related cardiometabolic abnormalities. We investigated associations of weight-loss diet-induced decreases in atherogenic gut-microbial metabolites, trimethylamine N-oxide (TMAO) and L-carnitine, with improvements in atherogenic lipoproteins containing apoCIII among patients with obesity.

SUBJECTS/METHODS

This study included overweight and obese adults who participated in a 2-year weight-loss dietary intervention, the POUNDS Lost trial. Blood levels of TMAO and L-carnitine were measured at baseline and 6 months after the intervention; 6-month changes in the metabolites were calculated. We evaluated 2-year changes in lipid profiles (n = 395) and cholesterol [Chol] in lipoprotein (very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL)) subfractions defined by the presence or absence of apoCIII (n = 277).

RESULTS

The initial (6-month) decrease in L-carnitine was significantly associated with long-term (2-year) reductions in non-HDL-Chol and LDL-Chol (p < 0.05). Also, the decrease in L-carnitine was significantly related to decreases in Chol in LDL with apoCIII (p = 0.034) and Chol in [LDL + VLDL] with apoCIII (p = 0.018). We found significant interactions between dietary fat and TMAO on changes in LDL-Chol (P_interaction= 0.013) and Chol in [LDL + VLDL] with apoCIII (P_interaction= 0.0048); a greater increase in TMAO was related to lesser improvements in the lipoprotein outcomes if participants consumed a high-fat compared to a low-fat diet.

CONCLUSIONS

Changes in TMAO and L-carnitine induced by weight-loss diets were associated with long-term improvements in atherogenic lipoproteins containing apoCIII, implicating that these metabolic changes might be predictive of an individual's response to the dietary treatment to modify the unfavorable lipid profiles in obese patients. Dietary fat intake might modify associations of TMAO changes with long-term improvements of atherogenic cholesterol metabolism in overweight and obese adults. CLINICALTRIALS.

GOV IDENTIFIER

NCT00072995.

Perfluorooctane sulfonate alternatives and metabolic syndrome in adults: New evidence from the Isomers of C8 Health Project in China

Chlorinated polyfluoroalkyl ether sulfonates (Cl-PFESAs), are ubiquitous alternatives to perfluorooctane sulfonate (PFOS), a widely used poly- and perfluoroalkyl substance (PFAS). Despite in vivo and in vitro evidence of metabolic toxicity, no study has explored associations of Cl-PFESAs concentrations with metabolic syndrome (MetS) in a human population. To help address this data gap, we quantified 32 PFAS, including 2 PFOS alternative Cl-PFESAs (6:2 and 8:2 Cl-PFESAs) in serum from 1228 adults participating in the cross-sectional Isomers of C8 Health Project in China study. The odds ratios (ORs) and 95% confidence intervals (CIs) of MetS and its various components were estimated using individual PFAS as a continuous or categorical predictor in multivariate regression models. The association between the overall mixture of PFAS and MetS was examined using probit Bayesian Kernel Machine Regression (BKMR-P). Greater serum PFAS concentrations were associated with higher odds of MetS and demonstrated a statistically significant dose-response trend (P for trend < 0.001). For example, each ln-unit (ng/mL) increase in serum 6:2 Cl-PFESA was associated with a higher prevalence of MetS (OR = 1.52, 95% CI: 1.25, 1.85). MetS was also 2.26 (95% CI: 1.59, 3.23) times more common in the highest quartile of serum 6:2 Cl-PFESA concentration than the lowest, and particularly high among women (OR = 6.41, 95% CI: 3.65, 11.24). The BKMR-P analysis showed a positive association between the overall mixture of measured PFAS and the odds of MetS, but was only limited to women. While our results suggest that exposure to Cl-PFESAs was associated with MetS, additional longitudinal studies are needed to more definitively address the potential health concerns of these PFOS alternatives.

Understanding the Impact of Perfluorinated Compounds on Cardiovascular Diseases and Their Risk Factors: A Meta-Analysis Study

Perfluorinated compounds (PFCs) are non-biodegradable synthetic chemical compounds that are widely used in manufacturing many household products. Many studies have reported the association between PFCs exposure with the risk of developing cardiovascular diseases (CVDs). However, those reports are still debatable, due to their findings. Thus, this review paper aimed to analyse the association of PFCs compound with CVDs and their risk factors in humans by systematic review and meta-analysis. Google Scholar, PubMed and ScienceDirect were searched for PFCs studies on CVDs and their risk from 2009 until present. The association of PFCs exposure with the prevalence of CVDs and their risk factors were assessed by calculating the quality criteria, odds ratios (ORs), and 95% confidence intervals (CIs). CVDs risk factors were divided into serum lipid profile (main risk factor) and other known risk factors. The meta-analysis was then used to derive a combined OR test for heterogeneity in findings between studies. Twenty-nine articles were included. Our meta-analysis indicated that PFCs exposure could be associated with CVDs (Test for overall effect: z = 2.2, p = 0.02; Test for heterogeneity: I² = 91.6%, CI = 0.92–1.58, p < 0.0001) and their risk factors (Test for overall effect: z = 4.03, p < 0.0001; Test for heterogeneity: I² = 85.8%, CI = 1.00–1.14, p < 0.0001). In serum lipids, total cholesterol levels are frequently reported associated with the exposure of PFCs. Among PFCs, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) exposure increased the risk of CVDs than other types of PFCs. Although the risk of PFOA and PFOS were positively associated with CVDs and their risk factors, more observational studies shall be carried out to identify the long-term effects of these contaminants in premature CVDs development in patients.

Per- and polyfluoroalkyl substances (PFASs) in Swedish household dust and exposure of pet cats

Per- and polyfluoroalkyl substances (PFASs) are used in a wide range of products and have been found ubiquitously in our indoor environment, and there is evidence that exposure to PFAS can lead to adverse endocrine effects, such as thyroid hormone disruption. Pet cats have a high dust intake due to their grooming behavior and have been shown to be a suitable sentinel species for assessment of toddler's exposure. Here we used paired household dust (n=46) and cat serum (n=27) samples to establish whether dust is a relevant exposure pathway to PFASs. An analytical method for PFAS analysis was optimized using a low volume of cat serum samples, combining solid-phase extraction and online sample cleanup. Dust was extracted with methanol by sonication and cleaned up by addition of active carbon. In total, 27 PFASs were analyzed by liquid chromatography/mass spectrometry analysis. The correlation between PFAS levels in dust and serum, serum lipids and thyroid hormone levels, and PFAS levels in dust between different rooms were statistically evaluated. PFOS and PFDA could be quantified in all cat serum samples (median 2300 pg/mL and 430 pg/mL, respectively), followed by PFOA (median 1100 pg/mL), quantified in 96% of the samples. The levels of 6:2 and 8:2 diPAPs were determined in 65% and 92% of the serum samples, respectively, and were an order of magnitude lower (1.4-160 pg/mL). Household dust on the other hand was dominated by 6:2 and 8:2 diPAPs, with a median of 65 ng/g dust and 49 ng/g dust, respectively. PFOS (median 13 ng/g dust) and PFOA (median 9 ng/g dust) were quantified in 93% of the dust samples. Only eight PFASs were detected (>LOD) in at least 50% of the samples of both matrices and could be paired. Significant correlations between cat serum and dust were found for PFOA (rS=0.32, p<0.049) and PFUnDA (rS=0.55, p<0.001). Significant positive correlations were found between serum total thyroxine (rS=0.11, p<0.05) and PFNA and between serum cholesterol and PFHpA (rS=0.46, p<0.01), PFUnDA (rS=0.40, p<0.05), PFDoDA (rS=0.44, p<0.01), and sum PFAS (rS=0.48, p<0.01). In conclusion, this study confirmed that dust is a relevant exposure pathway for the ingestion of some PFASs for cats, and the serum levels of PFASs could be of relevance for the cat's health.

Perfluorooctanoic acid induces liver and serum dyslipidemia in humanized PPARα mice fed an American diet

Per- and polyfluoroalkyl substances (PFAS) are pervasive in the environment resulting in nearly universal detection in people. Human serum PFAS concentrations are strongly associated with increased serum low-density lipoprotein cholesterol (LDL-C), and growing evidence suggests an association with serum triacylglycerides (TG). Here, we tested the hypothesis that perfluorooctanoic acid (PFOA) dysregulates liver and serum triacylglycerides in human peroxisome proliferator activated receptor α (hPPARα)-expressing mice fed an American diet. Mice were exposed to PFOA (3.5 mg/L) in drinking water for 6 weeks resulting in a serum concentration of 48 ± 9 μg/ml. In male and female hPPARα mice, PFOA increased total liver TG and TG substituted with saturated and monounsaturated fatty acids. Lack of expression of PPARα alone also increased total liver TG, and PFOA treatment had little effect on liver TG in PPARα null mice. In hPPARα mice, PFOA neither significantly increased nor decreased serum TG; however, there was a modest increase in TG associated with very low-density cholesterol particles in both sexes. Intriguingly, in female PPARα null mice, PFOA significantly increased serum TG, with a similar trend in males. PFOA also modified fatty acid and TG homeostasis-related gene expression in liver, in a hPPARα-dependent manner, but not in adipose. The results of our study and others reveal the importance of context (serum concentration and genotype) in determining the effect of PFOA on lipid homeostasis.

Serum perfluoroalkyl substances in relation to lipid metabolism in Chinese pregnant women

Laboratory and epidemiologic studies suggested that exposure to perfluoroalkyl substances (PFASs) could affect lipid metabolisms, but data remain limited for pregnant women. A total of 436 pregnant women were selected in Tangshan City, North China. Serum levels of 11 PFASs were determined in the early term of pregnancy. Four lipids (total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), and low-density lipoprotein (LDL)) were measured in the late term of pregnancy. Of 11 PFASs, seven had a detection rate of greater than 70%. After adjusting for potential confounders, natural log-transformed perfluororohexanesulfonic acid (ln PFHxS) was positively associated with TC (β: 0.184, 95% CI: 0.045-0.321), HDL (β: 0.040, 95% CI: 0.001-0.083), and LDL (β: 0.091, 95% CI: 0.001-0.185). Ln perfluoroundecanoic acid (PFUdA) was positively associated with HDL (β: 0.021, 95% CI: 0.001-0.044), while Ln perfluorodecanoic acid (PFDA) was negatively associated with LDL (β: -0.053, 95% CI: -0.098∼-0.009) and ln perfluorootanoic acid (PFOA) was negatively associated with LDL/HDL (β: -0.042, 95% CI: -0.075∼-0.009). In principal component analysis, the component with a large loading of 31.3% for PFOA, perfluorononanoic acid (PFNA), PFDA and PFUdA showed a negative association with LDL/HDL. After serum concentrations of PFASs were categorized into quartiles, a higher level of TC was seen in the second quartile of PFOA or PFNA than the first quartile, but a lower LDL/HDL ratio was seen in the fourth quartile of PFOA, PFUdA or PFDA. These results suggested that exposure to PFASs has a potential to influence lipid metabolisms in pregnant women.

Per- and Polyfluoroalkyl Substance Toxicity and Human Health Review: Current State of Knowledge and Strategies for Informing Future Research

Reports of environmental and human health impacts of per- and polyfluoroalkyl substances (PFAS) have greatly increased in the peer-reviewed literature. The goals of the present review are to assess the state of the science regarding toxicological effects of PFAS and to develop strategies for advancing knowledge on the health effects of this large family of chemicals. Currently, much of the toxicity data available for PFAS are for a handful of chemicals, primarily legacy PFAS such as perfluorooctanoic acid and perfluorooctane sulfonate. Epidemiological studies have revealed associations between exposure to specific PFAS and a variety of health effects, including altered immune and thyroid function, liver disease, lipid and insulin dysregulation, kidney disease, adverse reproductive and developmental outcomes, and cancer. Concordance with experimental animal data exists for many of these effects. However, information on modes of action and adverse outcome pathways must be expanded, and profound differences in PFAS toxicokinetic properties must be considered in understanding differences in responses between the sexes and among species and life stages. With many health effects noted for a relatively few example compounds and hundreds of other PFAS in commerce lacking toxicity data, more contemporary and high-throughput approaches such as read-across, molecular dynamics, and protein modeling are proposed to accelerate the development of toxicity information on emerging and legacy PFAS, individually and as mixtures. In addition, an appropriate degree of precaution, given what is already known from the PFAS examples noted, may be needed to protect human health. Environ Toxicol Chem 2021;40:606-630. © 2020 SETAC.

Diet as an Exposure Source and Mediator of Per- and Polyfluoroalkyl Substance (PFAS) Toxicity

Per- and polyfluoroalkyl substances (PFAS) are ubiquitously found in the environment due to their widespread commercial use and high chemical stability. Humans are exposed primarily through ingestion of contaminated water and food and epidemiological studies over the last several decades have shown that PFAS levels are associated with adverse chronic health effects, including cardiometabolic disorders such as hyperlipidemia and non-alcoholic fatty liver disease. Perhaps the most well-established effects, as demonstrated in animal studies and human epidemiological studies, are the metabolic alterations PFAS exposure can lead to, especially on lipid homeostasis and signaling. This altered lipid metabolism has often been linked to conditions such as dyslipidemia, leading to fatty liver disease and steatosis. Western diets enriched in high fat and high cholesterol containing foods may be an important human exposure route of PFAS and may also act as an important modulator of associated toxicities. In fact, the chemical structure of PFAS resemble fatty acids and may activate some of the same signaling cascades critical for endogenous metabolism. In this review we aim to outline known dietary exposure sources of PFAS, describe the detrimental metabolic health effects associated with PFAS exposure, and focus on studies examining emerging interaction of dietary effects with PFAS exposure that further alter the dysregulated metabolic state.

Dysregulated lipid and fatty acid metabolism link perfluoroalkyl substances exposure and impaired glucose metabolism in young adults

BACKGROUND

Per- and polyfluoroalkyl substances (PFASs) exposure is ubiquitous among the US population and has been linked to adverse health outcomes including cardiometabolic diseases, immune dysregulation and endocrine disruption. However, the metabolic mechanism underlying the adverse health effect of PFASs exposure is unknown.

OBJECTIVE

The aim of this project is to investigate the association between PFASs exposure and altered metabolic pathways linked to increased cardiometabolic risk in young adults.

METHODS

A total of 102 young adults with 82% overweight or obese participants were enrolled from Southern California between 2014 and 2017. Cardiometabolic outcomes were assessed including oral glucose tolerance test (OGTT) measures, body fat and lipid profiles. High-resolution metabolomics was used to quantify plasma exposure levels of three PFAS congeners and intensity profiles of the untargeted metabolome. Fasting concentrations of 45 targeted metabolites involved in fatty acid and lipid metabolism were used to verify untargeted metabolomics findings. Bayesian Kernel Machine Regression (BKMR) was used to examine the associations between PFAS exposure mixture and cardiometabolic outcomes adjusting for covariates. Mummichog pathway enrichment analysis was used to explore PFAS-associated metabolic pathways. Moreover, the effect of PFAS exposure on the metabolic network, including metabolomic profiles and cardiometabolic outcomes, was investigated.

RESULTS

Higher exposure to perfluorooctanoic acid (PFOA) was associated with higher 30-minute glucose levels and glucose area under the curve (AUC) during the OGTT (p < 0.001). PFAS exposure was also associated with altered lipid pathways, which contributed to the metabolic network connecting PFOA and higher glucose levels following the OGTT. Targeted metabolomics analysis indicated that higher PFOA exposure was associated with higher levels of glycerol (p = 0.006), which itself was associated with higher 30-minute glucose (p = 0.006).

CONCLUSIONS

Increased lipolysis and fatty acid oxidation could contribute to the biological mechanisms linking PFAS exposure and impaired glucose metabolism among young adults. Findings of this study warrants future experimental studies and epidemiological studies with larger sample size to replicate.

Plasma perfluoroalkyls are associated with decreased levels of proteomic inflammatory markers in a cross-sectional study of an elderly population

Perfluoroalkyl substances (PFAS) have been linked to immunotoxicity in experimental studies. Although PFAS exposure is associated with altered immune response in epidemiological studies of children, it is less known whether this is observed also in elderly adults. Eight PFAS and 86 proteins were measured in plasma from 965 elderly individuals from Sweden (all aged 70, 50% women). PFAS were measured using isotope-dilution ultra-pressure liquid chromatography coupled to tandem mass spectrometry. Proteins were measured using a multiplex proximity extension assay (PEA) and covered among others inflammatory marker proteins such as monocyte chemoattractant proteins, tumor necrosis factors, and interleukins. We examined cross-sectional associations using multivariable linear regression at two levels of adjustment. We observed significant decreases in levels of 24 proteins in relation to a ln-unit increase in PFAS concentrations following adjustment for sex, sample storage time in freezer, and correction for multiple testing. Associations of PFAS and hepatocyte growth factor (HGF) and macrophage colony-stimulating factor 1 (CSF-1) remained significant (p-value <0.05) following full covariate adjustment for smoking, exercise habits, education, energy, and alcohol intake, body mass index (BMI), glomular filtration rate (GFR) as well as corticoid- and COX-inhibitor treatment. CSF-1 was inversely associated with perfluorohexane sulfonic acid (PFHxS) β: -0.08: 95% confidence interval (CI); -0.13, -0.02), perfluorooctanoic acid (PFOA) β: -0.04: 95% CI; -0.07, -0.006, perfluorononanoic acid (PFNA) β: -0.04: 95% CI; -0.08, -0.003, perfluorodecanoic acid (PFDA) β: -0.03: 95% CI; -0.06, -0.003, and perfluoroundecanoic acid (PFUnDA) β: -0.05: 95% CI; -0.08, -0.02. The magnitude and direction of PFAS vs protein relationships were similar also for HGF. Our findings implicate PFAS exposure with decreased levels of proteomic markers of inflammation in elderly humans.

Review: Evolution of evidence on PFOA and health following the assessments of the C8 Science Panel

BACKGROUND

The C8 Science Panel was composed of three epidemiologists charged with studying the possible health effects of PFOA in a highly exposed population in the mid-Ohio Valley. The Panel determined in 2012 there was a 'probable link' (i.e., more probable than not based on the weight of the available scientific evidence) between PFOA and high cholesterol, thyroid disease, kidney and testicular cancer, pregnancy-induced hypertension, and ulcerative colitis.

OBJECTIVE

Here, former C8 Science Panel members and collaborators comment on the PFOA literature regarding thyroid disorders, cancer, immune and auto-immune disorders, liver disease, hypercholesterolemia, reproductive outcomes, neurotoxicity, and kidney disease. We also discuss developments regarding fate and transport, and pharmacokinetic models, and discuss causality assessment in cross-sectional associations among low-exposed populations.

DISCUSSION

For cancer, the epidemiologic evidence remains supportive but not definitive for kidney and testicular cancers. There is consistent evidence of a positive association between PFOA and cholesterol, but no evidence of an association with heart disease. There is evidence for an association with ulcerative colitis, but not for other auto-immune diseases. There is good evidence that PFOA is associated with immune response, but uneven evidence for an association with infectious disease. The evidence for an association between PFOA and thyroid and kidney disease is suggestive but uneven. There is evidence of an association with liver enzymes, but not with liver disease. There is little evidence of an association with neurotoxicity. Suggested reductions in birthweight may be due to reverse causality and/or confounding. Fate and transport models and pharmacokinetic models remain central to estimating past exposure for new cohorts, but are difficult to develop without good historical data on emissions of PFOA into the environment.

CONCLUSION

Overall, the epidemiologic evidence remains limited. For a few outcomes there has been some replication of our earlier findings. More longitudinal research is needed in large populations with large exposure contrasts. Additional cross-sectional studies of low exposed populations may be less informative.

Associations between apolipoprotein B and selected perfluoroalkyl substances among diabetics and nondiabetics

Previous population investigation of perfluoroalkyl substances (PFAS) features associations with lipids in a number of populations; these investigations have seldom included consideration of apolipoproteins. Apolipoprotein B (Apo B) fractions were considered in this descriptive analysis because they are essential to the assembly, transport, and cellular uptake of lipid classes associated with poorer health outcomes, and they are associated with incident and prevalent disease. Regression models stratified by diabetes and lipid lowering medication (LLM) status for data from National Health and Nutrition Examination Survey for 2007-2014 were fitted to interrogate associations between selected PFAS and Apo B for US adults aged ≥ 20 years. Adjusted concentrations of Apo B were positively associated with perfluorooctanoic acid (PFOA β = 0.03878, p < 0.01), perfluorooctane sulfonic acid (PFOS β = .02029, p = 0.02), and perfluorononanoic acid (PFNA β = .01968, p = .03) for nondiabetics who were not taking lipid lowering medications. These associations were not seen among diabetic participants, except for perfluorodecanoic acid (PFDA) in those taking LLMs (β = 0.03831, p = 0.02). We also note that LLMs have an inferred greater impact on Apo B in the diabetics compared to the nondiabetic populations. We have considered several sources of confounding and think the data are most consistent with a weak causal association that PFAS exposure increases Apo B. The rodent toxicology literature also contains evidence that PFAS disrupt fatty acid trafficking including Apo B, although how the specific findings may relate to circulating human Apo B concentrations is unclear. We therefore advocate for attempts to replicate the findings in other populations and to consider additional types of mechanistic studies.

Association between exposure to perfluoroalkyl substances and metabolic syndrome and related outcomes among older residents living near a Science Park in Taiwan

Perfluoroalkyl substances (PFASs) are an emerging class of artificial environmental chemicals that have multiple potentially harmful effects on health. The largest Science Park in Taiwan discharges wastewater containing PFASs into the Keya River, and a high concentration of PFASs has been found in this river and its aquatic creatures. We conducted a cross-sectional study from 2016 to 2017 of 397 subjects aged 55-75 years living near the river and evaluated the association of PFASs with metabolic syndrome and related outcomes. The results indicated that perfluorooctane sulfonate (PFOS) levels were positively associated with serum low-density lipoprotein (LDL) levels (P for trend = 0.03) and that perfluorononanoic acid (PFNA) and PFOS levels were positively correlated with uric acid levels (P for trend = 0.03 and 0.03). Perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUnDA) levels were negatively associated with serum triglyceride levels (P for trend = 0.014 and < 0.01). After excluding lipid-lowering drug users, the association between certain PFAS levels and the LDL level was significantly enhanced, but the downward trends of serum triglyceride levels were weakened. When stratified by sex, PFNA (P for trend <0.01), perfluorohexanesulfonate (PFHxS) (P for trend <0.01), and PFOS (P for trend <0.01) showed positive associations with the uric acid level only among males. In conclusion, our results showed that associations were consistently null between PFASs and metabolic syndrome. PFAS levels were associated with serum lipids, and lipid-lowering drugs may interfere with this relationship. Certain PFASs were found to be positively associated with uric acid levels, especially in males. Further studies are warranted to clarify the causal relationships.

Are Persistent Organic Pollutants Linked to Lipid Abnormalities, Atherosclerosis and Cardiovascular Disease? A Review

The term persistent organic pollutants (POPs) denotes chemicals with known or suspected adverse health effects in animals or humans and with chemical properties that make them accumulate in the environment, including animals or humans. Lipid-soluble POPs, like dioxins, polychlorinated biphenyls (PCBs) and organochlorine pesticides are transported by lipoproteins and accumulate in adipose tissue. High levels of these compounds in the circulation have been associated with elevated cholesterol and triglycerides in cross-sectional studies and with an increase in mainly low-density lipoprotein cholesterol in a longitudinal study. Also, non-lipid-soluble POPs, such as perfluoroalkyl substances (PFASs) compounds have been associated with increased total cholesterol levels. Carotid artery atherosclerosis has been related to elevated levels of mainly highly chlorinated PCBs and to highly fluorinated PFASs, but in this case only in women. Both cross-sectional and prospective studies have shown dioxins, PCBs, as well as PFASs to be linked to cardiovascular disease (CVD) and mortality. In conclusion, as highlighted in this review, several lines of evidence support the view that POPs of different chemical classes could be linked to lipid abnormalities, carotid atherosclerosis and overt CVD like myocardial infarction and stroke.