Impact of Redox Imbalance and Mitochondrial Dysfunction on Neurotoxicity Induced by Perfluorooctanoic Acid in Male Wistar Albino Rats (Rattus norvegicus).

Estimation of Serum PFOA Concentrations from Drinking and Non-Drinking Water Exposures.

Per- and polyfluoroalkyl substances (PFAS) have carcinogenic potential but are understudied in relation to childhood cancers. We examined associations between targeted and non-targeted PFAS measured in newborn dried blood spots (DBS) and the risk of childhood acute lymphoblastic leukemia (ALL) in Los Angeles County, California, accounting for maternal and child characteristics. ALL cases (n = 125) diagnosed before age 18 years during 2000-2015 and controls (n = 219) were selected from a registry-based study using stratified sampling based on birth year and birth address within a PFAS-contaminated water district according to the USEPA Third Unregulated Contaminant Monitoring Rule. We calculated design-based odds ratios (OR) and 95% confidence intervals (CI) for the effect of PFAS exposures, independently and adjusting for other PFAS. We also conducted non-linear and stratified analyses. Of the 17 PFAS quantified using targeted analysis, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) had the highest mean concentrations in DBS, with 4690 and 10,307 pg/g dried blood among cases compared to 4245 and 8142 pg/g dried blood among controls, respectively. The highest risks were observed for the 4th exposure quartile compared with the 1st quartile (PFOA OR = 1.56, CI: 0.42, 5.73; PFOS OR = 1.64, CI: 0.44, 6.14). In non-linear statistical analyses of joint PFOA and PFOS exposures adjusted for other detected PFAS, we also found that ALL risk increased with increasing levels of log2-PFOA and log2-PFOS. Non-targeted analysis identified 26 additional PFAS, for which elevated risk of childhood ALL was associated with a doubling of C4HF7O3 exposure (OR = 5.04, CI: 1.08, 23.63) and the highest quartile of C10HF19O5 exposure (OR = 5.20, CI: 1.15, 23.56). Associations were generally stronger among non-Hispanic participants compared to Hispanic participants, but these analyses were limited by small sample sizes and should be considered exploratory. There was some suggestion that high PFOA and PFOS exposures measured at birth, as well as certain PFAS detected by non-targeted approaches, were related to childhood ALL risk. This study of childhood ALL in Los Angeles County, California found increased risk among children with the highest PFOA and PFOS levels measured in neonatal dried blood spots. These risks were stronger among non-Hispanic children, and the greatest risk was observed for joint PFOA and PFOS exposure adjusting for other detected PFAS and maternal/child characteristics. We also observed possible associations with PFAS discovered by non-targeted analysis. Our results highlight the utility of dried blood spots as a matrix for assessing early life exposures as well as the value of hybrid targeted and non-targeted approaches to measure PFAS in health studies.

Gestation is a vulnerable window when exposure to per- and polyfluoroalkyl substances (PFAS) may impact child development and health. Epigenetic modification, including DNA methylation (DNAm), may be one mechanism linking prenatal PFAS exposure to offspring outcomes. We tested associations between prenatal PFAS and newborn DNAm in 1017 participants from 6 cohorts in the US Environmental influences on Child Health Outcomes consortium. Concentrations of PFAS [perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid] were measured in maternal serum or plasma. DNAm was quantified in newborn dried blood spot or umbilical cord blood leukocytes using the Infinium HumanMethylation450 (450K) or MethylationEPIC (EPIC) arrays. We tested associations between prenatal PFAS and neonatal blood DNAm on the 450K (n = 772) and EPIC (n = 245) arrays; results were meta-analysed across the platforms. Regional changes in DNAm were investigated, and findings were checked for replication in the Michigan Mother–Infant Pairs (MMIP) cohort (n = 140). Following correction for false discovery rate (q = 0.1 for meta-analyses), we identified an association between PFHxS and one cytosine–guanine (CpG) mapped to CASC3 (q = 0.065) that replicated in MMIP (P = .006). PFOS was associated with six CpG sites, of which five were mapped to the genes KIAA1841, ABR, LEP, SERPINA1, and LOXL1. One differentially methylated region (DMR) was associated with prenatal PFOA exposure, and one DMR was associated with PFOS exposure. In this multicohort analysis including a diverse group from the USA, PFOA, PFOS, PFHxS, and PFNA exposures in pregnancy were associated with offspring DNAm, and the implications for children’s health merit further exploration.

Perfluoroalkyl substances (PFAS) are chemicals with endocrine disrupting properties. Experimental studies indicate that PFAS have estrogenic effects by inducing aromatase activity. Sex hormone-binding globulin (SHBG) is a marker of the balance between estrogen and testosterone, as estrogen stimulates and testosterone inhibits SHBG production. To investigate associations between maternal PFAS concentrations and levels of SHBG and testosterone in pregnancy. In Odense Child Cohort (OCC), concentrations of PFAS: perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were measured in 1611 eligible women at median gestational week (GW) 12 (25th, 75th percentile: 10, 15). Among these, levels of sex hormone-binding globulin (SHBG), calculated free testosterone (Free-T), free androgen index (FAI), and total testosterone (TT) were assessed in 1048at median GW 29 (25th, 75th percentile: 28, 30). Associations between PFAS concentrations and levels of SHBG and testosterone were estimated using multiple linear regression models. The effect of combined exposure to PFAS was also assessed via Quantile G-Computation. A doubling in PFOS concentration was associated with an increment in SHBG concentration by 2.29% (95%CI: 0.04%, 4.59%) in adjusted analyses. PFOS exposure in the third tertile, as compared to the first tertile, significantly increased SHBG concentrations by 4.60% (95%CI: 0.82%, 8.53%). No significant association was demonstrated between PFAS and TT, however, a non-significant inverse association was found between PFAS and Free-T and FAI. Combined PFAS exposure was non-significantly associated with an increase in SHBG, and decrease in Free-T, FAI, and TT. PFOS exposure was associated with an increase in the proportion of estrogen effects to androgen effects, assessed by higher SHBG concentrations, in pregnant women. Estrogenic effects during pregnancy may have implications on offspring neural, metabolic, and endocrine development, hence supporting the necessity of a follow-up of offspring.

Perfluoroalkyl substances (PFAS) are the member of that class of compounds which includes at least one fluorine atom in their structure, are being used in various industrial and consumer products due to their unique chemical properties. Perfluorooctanoic sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are the most important and well-known components among PFAS. Perfluoroalkyl and polyfluoroalkyl substances (PFAS) exert various kinds of effects on living organisms, but the most serious ones are the metabolic effects. However, PFAS are inert metabolically itself, but they interfere with endogenous metabolic pathways and reactions, and indirectly affect the metabolism of the body. Unluckily, there are many other PFAS to those humans are exposed throughout their life which not only imparts harmful effects on adults but also in whole life. It has been quantified that PFAS are present in amniotic fluid, fetal tissue, breastmilk, lung, heart, umbilical cord, and brain, blood, and placenta which indicates PFAS exposure in infants from the very start of life. PFAS exposure to Nematodes for 72 h shows the evidence of neuropathology during the inspection of GABAergic, dopaminergic, serotoninergic, and cholinergic neuronal morphologies. Ingestion of mycotoxins causes complex problems to human health. Physio-chemical processing aimed to destroy and mineralize contaminants into carbon dioxide and water or less toxic products.

<h3>Objective</h3> Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) are two perfluoroalkyl substances (PFAS) widespread in industrial applications and consumer products. However, evidence substantiating occupations with elevated exposure is limited. The recent IARC classification of PFOA as carcinogenic has prompted concern about occupational exposure to PFAS for cancer prevention, particularly among women. We investigated the association of occupation and industry of employment with serum PFOA and PFOS biomarker concentrations in a national survey of Canadian adults, with a specific focus on exposure in female workers. <h3>Methods</h3> We conducted a cross-sectional study of 5,795 participants in four cycles of the Canadian Health Measures Survey between 2007-2011 and 2016-2019. Linear regression models adjusted for demographic, diet, and environmental factors were used to estimate predicted geometric means (GM) and geometric mean ratios (GMR) of PFOA and PFOS concentrations among workers in 137 occupation and industry groups, overall and stratified by sex. <h3>Results</h3> PFOA and PFOS concentrations were higher among participants who were older, male, East/Southeast Asian, urban residents or seafood consumers. Concentrations declined in successive CHMS cycles. By occupation, PFOA was elevated among workers in health services (GMR-PFOA 1.25; 95%CI: 1.10–1.43); labourers in processing and manufacturing; front-line protection services; and harvesting and landscaping labourers. Among women, predicted PFOA levels were also elevated in electrical and construction trades; and technical health occupations. For PFOS, aside from health-related occupations, results were similar. By industry, concentrations were elevated among workers in ambulatory care services (GMR-PFOA 1.12; 95%CI: 1.02–1.24) and clothing manufacturing (GMR-PFOS 2.22; 95%CI: 1.39–3.57). <h3>Conclusion</h3> Occupational and sex-based differences in PFOA and PFOS exposure are evident, with elevated exposure identified for workers in specific occupations, including health and manufacturing. Further research will examine exposure to other PFAS as well as associations with cancer risk. This research was supported by the Canadian Cancer Society.

Exposure to perfluoroalkyl substances and risk of hepatocellular carcinoma in a multiethnic cohort

Per- and polyfluoroalkyl substances (PFAS) are a unique class of over 15,000 manmade chemicals that are still widely used in manufacturing and are resistant to degradation. Accumulation in the environment and general population has been associated with an array of adverse health outcomes. Perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and perfluorohexanesulfonic acid (PFHxS) specifically have been associated with markers of liver injury, high serum cholesterol, thyroid disease, low fetal birth weight, suppressed vaccine response, and cancer. Exposure to PFAS is commonly investigated individually, however, humans are exposed to a multitude of PFAS daily. Additionally, with the pervasive nature of these chemical, people of all ages are affected by their toxic effects. This dissertation focuses on both a global and targeted approach to elucidating mechanisms of PFAS liver toxicity, both individually and as a mixture, in young and adult mice. The studies herein introduce novel approaches, including offspring liver omics’ analyses of perinatal PFAS mixture exposures and PFOS exposures in targeted protein murine knockout mouse models, to understand and evaluate the underlying mechanisms of PFAS liver toxicity in both neonatal and adult mice. In manuscript 1, livers from pups gestationally and lactationally exposed to individual PFOA, PFOS, PFHxS, or a PFAS mixture were investigated for proteomic alterations at postnatal day (PND) 21. Herein, sequential window acquisition of all theoretical mass spectra - liquid chromatography-mass spectrometry (SWATH-LC/MS) and Ingenuity Pathway Analysis (IPA) software were utilized to investigate global proteomic changes in the exposed offsprings’ liver. Individual and commonly observed proteins between treatments and diets were explored to tease out the differing proteomic signatures. Specific proteins involved in pathways concerning lipid transport, storage, synthesis, and catabolism, xenobiotic metabolism, and inflammation were investigated. In manuscript 2, neonatal livers indirectly exposed to PFOA, PFOS, PFHxS, or a PFAS mixture through gestation and lactation were investigated for transcriptomic alterations at postnatal day (PND) 21. Herein, the QuantSeq 3' mRNA-Seq Library Prep Kit, BlueBee genomics platform, and IPA software were utilized to investigate global transcriptomic changes in the exposed pup livers. Treatment and diet-specific genes that were individually or commonly observed were investigated to tease out the unique transcriptomic signatures. Selected genes involved in pathways regarding xenobiotic metabolism, inflammation, and lipid transport, storage, synthesis, and catabolism were further investigated. In manuscript 3, a knockout (KO) mouse model with a specific targeted deletion of organic anion transporting polypeptide 2b1 (Oatp2b1) was utilized to investigate the contribution of this

Time-dependent effects of perfluorinated compounds on viability in cerebellar granule neurons: Dependence on carbon chain length and functional group attached

Background: Chronic exposure to long-term exposures to per- and polyfluoroalkyl substances (PFAS), widely known as “forever chemicals”, has been associated with multiple negative health outcomes including increased risk of cancer. Perfluorooctanesulfonic acid (PFOS), a “long-chain” subtype of PFAS, has high bioaccumulation potential with a long elimination half-life. PFOS is frequently detected in drinking water leading to its high absorption through the gastrointestinal tract. Recent studies demonstrate that PFAS exposures promote intestinal inflammation and gut barrier dysfunction. However, how a long-term PFOS exposure affects colorectal cancer (CRC) progression is not known. Therefore, the purpose of this study is to delineate the effect of PFOS exposure on CRC cell proliferation and test the potential mitigation strategy for the harmful effects of PFOS. Methods: SW480 and HCT116 cells have been treated with 1 ug/mL PFOS and proliferation was measured at 1, 2, and 3 months using the Presto Blue Cell Viability Reagent fluorescence assay. Proliferation markers were assessed by qPCR and Western blot. Control and PFOS exposed cells were treated with sulforaphane, a nuclear factor erythroid 2-related factor 2 (Nrf-2) inducer, at concentration 5, 10 and 20 uM for 72 hours. Results: We show that chronic, low-dose PFOS exposure promotes proliferation of SW480 and HCT116 cell lines starting at 3 months since the first exposure. The increase in proliferation is associated with upregulation of Cyclin D, pAkt and FASN. We also show that sulforaphane significantly decreases proliferation of HCT116 and SW480 cells, and its efficacy is significantly higher in PFOS exposed CRC cells. The current studies show no effect on sulforaphane on normal colon epithelium cells. Conclusion: Our studies suggest that chronic PFOS exposure promotes proliferation of CRC cells by increasing pro-carcinogenic gene expression and signaling. Furthermore, our findings suggest that supplementation of diet sulforaphane can potentially mitigate the harmful effects from PFOS exposure. Our studies warrant further investigation of the mechanisms behind the effect of PFOS exposure on cancer progression that would guide development of effective intervention strategies to mitigate the harmful effects of the exposure to “forever chemicals”. Citation Format: Jerika Durham, Josiane Weber Tessmann, Bernhard Hennig, Yekaterina Zaytseva. Chronic perfluorooctanesulfonic acid exposure promotes proliferation of colorectal cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1478.

Invited Perspective: Challenges in Evaluating the Effect of Per- and Polyfluoroalkyl Substance Mixtures on Polycystic Ovarian Syndrome

Environmentally relevant concentrations of individual per- and polyfluoroalkyl substances (PFAS) and a PFAS mixture impact proliferation, migration, and gene transcription in a human myometrial cell line.

Association of polyfluoroalkyl chemical exposure with serum lipids in children

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

Background:Per- and polyfluoroalkyl substances (PFAS) are a diverse class of industrial chemicals with widespread environmental occurrence. Exposure to long-chain PFAS is associated with developmental toxicity, prompting their replacement with short-chain and fluoroether compounds. There is growing public concern over the safety of replacement PFAS.Objective:We aimed to group PFAS based on shared toxicity phenotypes.Methods:Zebrafish were developmentally exposed to 4,8-dioxa-3H-perfluorononanoate (ADONA), perfluoro-2-propoxypropanoic acid (GenX Free Acid), perfluoro-3,6-dioxa-4-methyl-7-octene-1-sulfonic acid (PFESA1), perfluorohexanesulfonic acid (PFHxS), perfluorohexanoic acid (PFHxA), perfluoro-n-octanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), or 0.4% dimethyl sulfoxide (DMSO) daily from 0–5 d post fertilization (dpf). At 6 dpf, developmental toxicity and developmental neurotoxicity assays were performed, and targeted analytical chemistry was used to measure media and tissue doses. To test whether aliphatic sulfonic acid PFAS cause the same toxicity phenotypes, perfluorobutanesulfonic acid (PFBS; 4-carbon), perfluoropentanesulfonic acid (PFPeS; 5-carbon), PFHxS (6-carbon), perfluoroheptanesulfonic acid (PFHpS; 7-carbon), and PFOS (8-carbon) were evaluated.Results:PFHxS or PFOS exposure caused failed swim bladder inflation, abnormal ventroflexion of the tail, and hyperactivity at nonteratogenic concentrations. Exposure to PFHxA resulted in a unique hyperactivity signature. ADONA, PFESA1, or PFOA exposure resulted in detectable levels of parent compound in larval tissue but yielded negative toxicity results. GenX was unstable in DMSO, but stable and negative for toxicity when diluted in deionized water. Exposure to PFPeS, PFHxS, PFHpS, or PFOS resulted in a shared toxicity phenotype characterized by body axis and swim bladder defects and hyperactivity.Conclusions:All emerging fluoroether PFAS tested were negative for evaluated outcomes. Two unique toxicity signatures were identified arising from structurally dissimilar PFAS. Among sulfonic acid aliphatic PFAS, chemical potencies were correlated with increasing carbon chain length for developmental neurotoxicity, but not developmental toxicity. This study identified relationships between chemical structures and in vivo phenotypes that may arise from shared mechanisms of PFAS toxicity. These data suggest that developmental neurotoxicity is an important end point to consider for this class of widely occurring environmental chemicals. https://doi.org/10.1289/EHP5843