Concentrations and association between exposure to mixed perfluoroalkyl and polyfluoroalkyl substances and glycometabolism among adolescents

The effect and potential mechanisms of per- and polyfluoroalkyl substances (PFAS) exposure on kidney stone risk

Exposure to per- and polyfluoroalkyl substances (PFAS) may be associated with an increased prevalence of some kidney diseases. Kidney stones are common and have a high prevalence of kidney diseases. However, there is no evidence for the effect and potential mechanisms of PFAS on kidney stone risk. In this study, we designed a cross-sectional study using the National Health and Nutrition Examination Surveys (NHANES) data from 2017 to 2020. Our results revealed that PFAS were positively associated with kidney stone risk, and PFDA was the main contributing compound among PFAS. The triglyceride-glucose (TyG) index and the systemic immune-inflammatory (SII) index had significant mediation effects. In addition, target proteins, such as IL-6, TNF, ALB, IL-1B, and AKT1, and signaling pathways, including TNF and IL-17 pathways, might be potential mechanisms of PFAS in promoting kidney stone risk. In conclusion, PFAS, especially PFDA, increases the risk of kidney stones by the mediation effects of the TyG index and SII index. TNF and IL-17 signaling pathways may be potential mechanisms. Our findings provide new evidence for the effects and potential mechanisms of PFAS exposure in increasing kidney stone risk. However, in the future, it is still imperative to further explore and validate the underlying mechanisms of PFAS-induced kidney stone formation through experimental studies.

Association between endocrine disrupting chemicals exposure and diabetic kidney disease in adults: A national cross-sectional NHANES study

BACKGROUND

Diabetic kidney disease (DKD) is a global public health concern. Environmental factors are increasingly recognized as significant risk factors that cannot be overlooked, and certain environmental pollutants exhibit endocrine-disrupting properties. Previous research on the association between endocrine-disrupting chemicals (EDCs) and DKD has been notably limited.

METHODS

This study investigated the association between exposure to 25 EDC metabolites and DKD in 1421 U.S. adults from the 2015-2018 National Health and Nutrition Examination Survey (NHANES). We used logistic regression, restricted cubic spline regression, weighted quantile sum (WQS) regression, and bayesian kernel machine regression (BKMR) models to assess the association between individual and co-exposure to multiple EDCs and DKD. Subgroup analyses and interaction tests were performed to investigate whether this association was stable across the population. Additionally, mediation analysis was used to explore the mediating role of serum globulins in the association between Pb exposure and DKD.

RESULTS

In logistic regression models, N-Acetyl-S-(2-hydroxypropyl)-L-cysteine (2HPMA), N-Acetyl-S-(4-hydroxy-2-butenyl)-L-cysteine (MHBMA3), Phenylglyoxylic acid (PGA), and lead (Pb) were significantly positively associated with diabetes. Restricted cubic spline (RCS) analyses also revealed significant non-linear positive associations between 2HPMA, MHBMA3, and DKD. Perfluorohexane sulfonic acid (PFHxS), n-perfluorooctanoic acid (n-PFOA), n-perfluorooctane sulfonic acid (n-PFOS), and Perfluoromethylheptane sulfonic acid isomers (Sm-PFOS) were significantly negatively associated with DKD. Furthermore, co-exposure to metals and metalloid was positively associated with DKD in both the WQS regression and the BKMR models, with Pb as the primary contributing factor. Mediation analysis showed that globulin mediated the association between Pb exposure and DKD, with a mediation proportion of 7.25 % (P = 0.046). Co-exposure to perfluoroalkyl and polyfluoroalkyl substances (PFASs) was negatively correlated with DKD, and subgroup analyses revealed that this correlation was more pronounced in the obese group (BMI ≥30 kg/m²). The BKMR analysis revealed potential interactions among various chemical compounds, such as N-Acetyl-S-(2-hydroxypropyl)-L-cysteine (2HPMA), 2-Methylhippuric acid (2MHA), N-Acetyl-S-(4-hydroxy-2-methyl-2-butenyl)-L-cysteine (IPM3), mercury (Hg), and cadmium (Cd), in a model simulating co-exposure to metals and metalloid, as well as to volatile organic compound metabolites (mVOCs).

CONCLUSION

The findings suggest an association between individual or co-exposure to EDC metabolites and DKD, providing valid evidence for DKD prevention from the perspective of EDCs exposure. However, more prospective studies are needed to elucidate the potential mechanisms underlying these findings.

Relationship of perfluoroalkyl chemicals with chronic obstructive pulmonary disease: A cross-sectional study

Perfluoroalkyl chemicals are one of the most stable substances in industry and have become ubiquitous contaminants owing to their persistence in the environment. This study enrolled 1,953 participants aged ≥40 years old using data from the National Health and Nutrition Examination Survey (NHANES). We selected four perfluoroalkyl chemicals with a detection frequency of more than 80%, including perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonic acid (PFOS). Multivariate logistic regression was performed to determine the relationship of serum perfluoroalkyl chemicals with COPD and airflow limitation. We evaluated the interaction between perfluoroalkyl chemicals and lung function using multivariate linear regression analyses. Our results showed that the prevalence of COPD was not significantly related to serum PFHxS, PFNA, PFOA, and PFOS. Airflow limitation was positively linked with serum PFHxS, PFOA, and PFOS. However, these significant differences were not robust after adjustment of all confounders of interest. Serum PFHxS, PFOA, and PFOS were all positively related to the forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF). However, only PFOA remained significantly linked with the FEV1 and FVC after covariate adjustment. These results indicated that there was no significant interaction between exposure to perfluoroalkyl chemicals and the prevalence of COPD. Higher levels of serum PFOA appeared to be related to higher measures of FEV1 and FVC.

Environment-wide association study of five per- and polyfluoroalkyl substance (PFASs) exposure pathways in Korean adolescents from the Korean National Environmental Health Survey (2018-2020)

Per- and polyfluoroalkyl substances (PFASs) are widely used in consumer products and are easily encountered in daily life. PFASs that accumulate in the human body can negatively affect adolescent health. This study aimed to identify key exposure pathways that influence serum PFAS levels in Korean adolescents, using data from the Korean National Environmental Health Survey (2018-2020) cycle 4. By employing an environment-wide association study, we assessed residential, lifestyle, and dietary factors associated with serum PFAS levels. Serum levels of five PFAS compounds-perfluorooctanoic acid, perfluorooctane sulfonate, perfluorohexane sulfonate, perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA)-were measured in 825 adolescents. Multivariable linear regressions were performed to explore the association between serum PFAS levels and 102 potential exposure-pathway variables. The Benjamini-Hochberg procedure was then applied to calculate false discovery rate-adjusted p-values, with values < 0.01 considered statistically significant. For internal validation, least absolute shrinkage and selection operator regression was conducted 3000 times. We found that frequent fish consumption (>once a week) was strongly associated with increased serum levels of PFNA and PFDA. Frequent consumption of shellfish (>once a month), crustaceans (>once a week), and vegetables (≥once a day) was associated with increased serum levels of PFDA. Living near roads with self-reported high traffic volume was linked to higher PFDA concentrations. Further research is necessary to assess additional exposure pathways and to develop effective strategies to minimize PFAS exposure during adolescence.

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

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

Mitigation PFHxA-induced neurotoxicity in Carassius auratus brain cells by selenium-enriched Bacillus subtilis via the BDNF/PI3K/AKT/GSK-3β pathway

As emerging contaminants growing threat to aquatic organisms, explore effective mitigation strategies is particularly important. Our previous studies have shown that selenium-rich Bacillus subtilis can not only alleviate the cause of brain damage by perfluorohexanoic acid (PFHxA) in Carassius auratus via the intestinal axis of the brain, but its metabolites can also alleviate PFHxA toxicity. This study further explores the potential mechanism through in vitro experiments. Findings demonstrate that apoptosis caused by PFHXA is effectively reduced with the use of selenium-rich Bacillus subtilis, which operates through the BDNF/PI3K/AKT/GSK-3β signalling pathway. Furthermore, utilisation of LY294002 and LICl inhibitors provided additional confirmation of the pivotal function of this pathway in neuroprotection. Our study results emphasize the significance of the PI3K/AKT/GSK-3β signalling pathway in promoting neuronal survival. Additionally, our findings establish a novel theoretical framework for using selenium-enriched Bacillus subtilis in environmental toxicology. Selenium-enriched Bacillus subtilis can be used as a novel microecological preparation. Implementing this approach could effectively counteract neurotoxic consequences of emerging contaminants, hence safeguarding and preserving aquatic ecosystems.

Relationship between per-fluoroalkyl and polyfluoroalkyl substance exposure and insulin resistance in nondiabetic adults: Evidence from NHANES 2003-2018

BACKGROUND

Studies have linked per- and polyfluoroalkyl substances (PFAS) to chronic metabolic diseases. However, the relationship between PFAS exposure and insulin resistance (IR), a key pathophysiological basis of these metabolic diseases, in nondiabetic individuals have yet to be determined.

METHODS

This study analyzed data from 3909 participants (aged ≥20) from the NHANES 2003-2018 to investigate the associations between serum levels of seven PFAS and and IR indicators, including including HOMA-IR, HOMA-β, fasting insulin, QUICKI, and TyG index. Linear and logistic regression models were used, along with a restricted cubic spline to assess dose-response. Weighted quantile sum (WQS) regression and quantile g-computation (qgcomp) models were used to assess the association between mixed PFAS exposure and IR.

RESULTS

Linear regression revealed that elevated exposure to PFOS [β (95 % CI): 0.04 (0.02, 0.06)], PFOA [0.04 (0.01, 0.06)], and Me_PFOSA_AcOH [0.04 (0.02, 0.06)] was associated with a higher TyG index in adults. Notably, Me_PFOSA_AcOH was negatively associated with IR when assessed by HOMA-IR >2.6 [OR (95 % CI): 0.88 (0.79, 0.98)], although this was not supported by linear regression findings. When IR was defined by a TyG index >8.6, exposure to the highest quartiles of PFOS, PFOA, and Me_PFOSA_AcOH was associated with an increased risk of IR by 63 %, 42 %, and 85 %, respectively [1.63 (1.21, 2.20); 1.42 (1.06, 1.92); 1.85 (1.37, 2.50)]. PFOS, PFOA, and Me_PFOSA_AcOH demonstrated a nonlinear dose-response relationship with IR risk. The WQS and qgcomp models revealed significant positive correlations with the TyG index.

CONCLUSION

Mixed PFAS exposure in US nondiabetic adults was positively associated with IR, as indicated by the TyG index, particularly for PFOS, PFOA, and Me_PFOSA_AcOH. Further research is needed to establish causality, and reinforcing environmental risk mitigation strategies to reduce PFAS exposure is recommended.

TLR4 as a Potential Target of Me-PFOSA-AcOH Leading to Cardiovascular Diseases: Evidence from NHANES 2013-2018 and Molecular Docking

BACKGROUND

Concerns have been raised regarding the effects of perfluoroalkyl substance (PFAS) exposure on cardiovascular diseases (CVD), but clear evidence linking PFAS exposure to CVD is lacking, and the mechanism remains unclear.

OBJECTIVES

To study the association between PFASs and CVD in U.S. population, and to reveal the mechanism of PFASs' effects on CVD.

METHODS

To assess the relationships between individual blood serum PFAS levels and the risk of total CVD or its subtypes, multivariable logistic regression analysis and partial least squares discriminant analysis (PLS-DA) were conducted on all participants or subgroups among 3391 adults from the National Health and Nutrition Examination Survey (NHANES). The SuperPred and GeneCards databases were utilized to identify potential targets related to PFAS and CVD, respectively. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of intersection genes were performed using Metascape. Protein interaction networks were generated, and core targets were identified with STRING. Molecular docking was achieved using Autodock Vina 1.1.2.

RESULTS

There was a positive association between Me-PFOSA-AcOH and CVD (OR = 1.28, p = 0.022), especially coronary heart disease (CHD) (OR = 1.47, p = 0.007) and heart attack (OR = 1.58, p < 0.001) after adjusting for all potential covariates. Me-PFOSA-AcOH contributed the most to distinguishing between individuals in terms of CVD and non-CVD. Significant moderating effects for Me-PFOSA-AcOH were observed in the subgroup analysis stratified by sex, ethnicity, education level, PIR, BMI, smoking status, physical activity, and hypertension (p < 0.05). The potential intersection targets were mainly enriched in CVD-related pathways, including the inflammatory response, neuroactive ligand-receptor interaction, MAPK signaling pathway, and arachidonic acid metabolism. TLR4 was identified as the core target for the effects of Me-PFOSA-AcOH on CVD. Molecular docking results revealed that the binding energy of Me-PFOSA-AcOH to the TLR4-MD-2 complex was -7.2 kcal/mol, suggesting that Me-PFOSA-AcOH binds well to the TLR4-MD-2 complex.

CONCLUSIONS

Me-PFOSA-AcOH exposure was significantly associated with CVD. Network toxicology and molecular docking uncovered novel molecular targets, such as TLR4, and identified the inflammatory and metabolic mechanisms underlying Me-PFOSA-AcOH-induced CVD.

Association of exposure to multiple perfluoroalkyl and polyfluoroalkyl substances and glucose metabolism in National Health and Nutrition Examination Survey 2017-2018

Objective

To investigate the relationships between perfluoroalkyl and polyfluoroalkyl substances (PFASs) exposure and glucose metabolism indices.

Methods

Data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018 waves were used. A total of 611 participants with information on serum PFASs (perfluorononanoic acid (PFNA); perfluorooctanoic acid (PFOA); perfluoroundecanoic acid (PFUA); perfluorohexane sulfonic acid (PFHxS); perfluorooctane sulfonates acid (PFOS); perfluorodecanoic acid (PFDeA)), glucose metabolism indices (fasting plasma glucose (FPG), homeostasis model assessment for insulin resistance (HOMA-IR) and insulin) as well as selected covariates were included. We used cluster analysis to categorize the participants into three exposure subgroups and compared glucose metabolism index levels between the subgroups. Least absolute shrinkage and selection operator (LASSO), multiple linear regression analysis and Bayesian kernel machine regression (BKMR) were used to assess the effects of single and mixed PFASs exposures and glucose metabolism.

Results

The cluster analysis results revealed overlapping exposure types among people with higher PFASs exposure. As the level of PFAS exposure increased, FPG level showed an upward linear trend (p < 0.001), whereas insulin levels demonstrated a downward linear trend (p = 0.012). LASSO and multiple linear regression analysis showed that PFNA and FPG had a positive relationship (>50 years-old group: β = 0.059, p < 0.001). PFOA, PFUA, and PFHxS (≤50 years-old group: insulin β = -0.194, p < 0.001, HOMA-IR β = -0.132, p = 0.020) showed negative correlation with HOMA-IR/insulin. PFNA (>50 years-old group: insulin β = 0.191, p = 0.018, HOMA-IR β = 0.220, p = 0.013) showed positive correlation with HOMA-IR/insulin, which was essentially the same as results that obtained for the univariate exposure-response map in the BKMR model. Association of exposure to PFASs on glucose metabolism indices showed positive interactions between PFOS and PFHxS and negative interactions between PFOA and PFNA/PFOS/PFHxS.

Conclusion

Our study provides evidence that positive and negative correlations between PFASs and FPG and HOMA-IR/insulin levels are observed, respectively. Combined effects and interactions between PFASs. Given the higher risk of glucose metabolism associated with elevated levels of PFAS, future studies are needed to explore the potential underlying mechanisms.

Associations of prenatal exposure to per- and polyfluoroalkyl substances and fetal sex hormones in the Guangxi Zhuang Birth Cohort Study: Greater effect of long-chain PFAS

Fetal sex hormone homeostasis disruption could lead to reproductive and developmental abnormalities. However, previous studies have reported inconsistent findings regarding the association of maternal per- and polyfluoroalkyl substances (PFAS) exposure with fetal sex hormone levels. A total of 277 mother-infant pairs from the Guangxi Zhuang Birth Cohort Study between 2015 and 2019 were selected. We quantified nine PFAS in maternal serum in early pregnancy, and detected three sex hormones, namely, estradiol (E2), progesterone (P4) and testosterone (TT), in cord blood. The generalized linear model (GLM) and Bayesian kernel machine regression (BKMR) model were used for single- and multiple-exposure analyses, respectively. In the GLM, there was no significant association between an individual PFAS and any hormone level or the E2/TT ratio, but a negative association between perfluorododecanoic acid (PFDoA) exposure and P4 levels in female infants was observed after stratification by sex. In the BKMR, a mixture of nine PFAS was positively associated with E2 levels and the E2/TT ratio, with the same main contributors, i.e., perfluoroundecanoic acid (PFUnA). And PFAS mixtures were not associated with P4 or TT levels. After stratification by infant sex, positive associations of PFAS mixtures with E2 levels and the E2/TT ratio were observed only in male infants, with the same main contributors, i.e., PFUnA. There was a positive association between PFAS mixtures and P4 levels in male infants, in which PFUnA was the main contributor; but a reverse association between PFAS mixtures and P4 levels in female infants, in which PFDoA was the main contributor. This study suggested that prenatal exposure to PFAS mixtures is associated with fetal sex hormones, and long-chain PFAS may play an important role in this association. Furthermore, sex differences in the association of maternal PFAS exposure with E2 and P4 levels need additional attention.

Per- and Poly-fluoroalkyl Substances and Bile Acid Profiles in Pregnant Women

Alterations in bile acid (BA) profiles are closely associated with adverse outcomes in pregnant women and their offspring and may be one potential pathway underlying the related metabolic effects of per- and poly-fluoroalkyl substances (PFAS) exposure. However, evidence of associations between PFAS exposure and BA profiles in pregnant women is scarce. This study examined the associations of individual PFAS and PFAS mixture with BA profiles of pregnant women. We obtained quantitative data on the plasma concentrations of 13 PFAS and 15 BAs in 645 pregnant women from the Jiashan birth cohort. In Bayesian kernel machine regression models, the PFAS mixture was associated with increased plasma CA, TCA, TCDCA, and GLCA levels but with decreased GCA and LCA concentrations. Furthermore, the PFAS mixture was associated with increased concentrations of total BAs and the secondary/primary BA ratio but with decreased conjugated/unconjugated and glycine/taurine-conjugated BA ratios. PFHxS, PFUdA, PFOS, PFNA, and PFDA were the dominant contributors. The results of the linear regression analysis of individual PFAS were generally similar. Our findings provide the first epidemiological evidence for the associations of a PFAS mixture with BA profiles in pregnant women and may provide explanatory insights into the biological pathways underlying the related metabolic effects of PFAS exposure.