Perfluorooctanoic acid exposure triggers oxidative stress in the mouse pancreas

Bioaccumulation of perfluorooctane sulfonic acid (PFOS) and oxidative stress in snapping turtles in New York, USA

Perfluorooctane sulfonic acid (PFOS) is an anthropogenic chemical found in aqueous film-forming foams (AFFFs) and many consumer products. Despite its environmental ubiquity and persistence, little is known about the effects of PFOS on stress levels in wild animals. Here, we examined PFOS bioaccumulation and correlations between PFOS exposure and oxidative stress in snapping turtles (Chelydra serpentina) downstream of Griffiss Air Force Base in Rome, New York, a known source of AFFF contamination. Maximum concentrations of PFOS were extrapolated as 41.7 ppb and 498 ppb in water and turtle samples, respectively; in comparison, the proposed United States national advisory concentration of PFOS in drinking water is currently 0.00002 ppb. PFOS concentrations declined with distance downstream from the base and were lower in other local water bodies. Indices of oxidative stress were positively correlated with plasma PFOS concentrations in snapping turtles. These data illuminate the potential for bioaccumulation and increasing oxidative stress levels associated with PFOS contamination in a wild population of aquatic turtles.

Evidence on the genotoxic and ecotoxic effects of PFOA, PFOS and their mixture on human lymphocytes and bacteria

Considering that the PFOA and PFOS are widely spread chemicals with harmful effects in human and environmental health as well as the increasing interest of the scientific community in the implications that might present especially when they co-exist, this study aims to assess their harmful impacts, both individually and as a mixture on human lymphocytes and aquatic microorganisms. The cytokinesis-block micronucleus (CBMN) assay was used to examine their potential for cytotoxicity and genotoxicity towards human cells, and Microtox assay using Aliivibrio fischeri assay was used to estimate the environmental risk. Regarding the human lymphocytes, the tested concentrations ranged between 250 and 1000 μg L-1, for all cases. PFOA increased slightly the frequency of micronuclei (MN) but without statistical significance. In the case of PFOS, our results showed a dose-dependent increase in the frequency of micronuclei which showed a statistically significant difference (p < 0.001) at 1000 μg L-1, which is the highest studied concentration. Regarding the CBPI index, statistically significant (p < 0.05, p < 0.01, and p < 0.001 respectively) differences were observed at all studied concentrations of PFOS, compared to the control. The mixture was found to be more cytotoxic and genotoxic than the individual tested compounds, causing a higher decrease at the CBPI index even in lower concentrations and increase at the MN frequencies. Aliivibrio fischeri was exposed to various concentrations in the range of 0.5 μg L-1- 20 mg L-1, for 5 and 15 min and significant increase in the inhibition percentage at the highest tested concentration of their mixture after 15 min was observed.

Occurrence of traffic related trace elements and organic micropollutants in tunnel wash water

Substantially polluted tunnel wash water (TWW) is produced during road tunnel maintenance. Previous literature has reported the presence of trace elements and polycyclic aromatic hydrocarbons (PAHs). However, it was hypothesized that other organic pollutants are present, and more knowledge is needed to prevent environmental harm. This study reveals for the first time the presence of four short- and 17 long-chained per- and polyfluoroalkyl substances (PFASs), three benzothiazoles (BTHs), six benzotriazoles (BTRs), four bisphenols, and four benzophenones in TWW from a Norwegian road tunnel over a period of three years. Concentrations of PAHs, PFASs, BTHs, and BTRs were higher than previously reported in e.g., road runoff and municipal wastewater. Trace elements and PAHs were largely particulate matter associated, while PFASs, BTHs, BTRs, bisphenols, and benzophenones were predominantly dissolved. 26 of the determined contaminants were classified as persistent, mobile, and toxic (PMT) and are of special concern. It was recommended that regulations for TWW quality should be expanded to include PMT contaminants (such as PFPeA, PFBS, BTR, and 4-OH-BzP) and markers of pollution (like 2-M-BTH, 2-OH-BTH, and 2-S-BTH from tire wear particles). These findings highlight the need to treat TWW before discharge into the environment, addressing both, particulate matter associated and dissolved contaminants.

Current state of knowledge of environmental occurrence, toxic effects, and advanced treatment of PFOS and PFOA

Per- and polyfluoroalkyl substances (PFAS) are anthropogenic synthetic compounds, with high chemical and thermal stability and a persistent, stable and bioaccumulative nature that renders them a potential hazard for the environment, its organisms, and humans alike. Perfluorooctane sulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA) are the most well-known substances of this category and even though they are phased out from production they are still highly detectable in several environmental matrices. As a result, they have been spread globally in water sources, soil and biota exerting toxic and detrimental effects. Therefore, up and coming technologies, namely advanced oxidation processes (AOPs) and advanced reduction processes (ARPs) are being tested for their implementation in the degradation of these pollutants. Thus, the present review compiles the current knowledge on the occurrence of PFOS and PFOA in the environment, the various toxic effects they have induced in different organisms as well as the ability of AOPs and ARPs to diminish and/or eliminate them from the environment.

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.

A systematic review on distribution, sources and sorption of perfluoroalkyl acids (PFAAs) in soil and their plant uptake

Perfluoroalkyl acids (PFAAs) are ubiquitous in environment, which have attracted increasing concerns in recent years. This study collected the data on PFAAs concentrations in 1042 soil samples from 15 countries and comprehensively reviewed the spatial distribution, sources, sorption mechanisms of PFAAs in soil and their plant uptake. PFAAs are widely detected in soils from many countries worldwide and their distribution is related to the emission of the fluorine-containing organic industry. Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are found to be the predominant PFAAs in soil. Industrial emission is the main source of PFAAs contributing 49.9% of the total concentrations of PFAAs (Ʃ PFAAs) in soil, followed by activated sludge treated by wastewater treatment plants (WWTPs) (19.9%) and irrigation of effluents from WWTPs, usage of aqueous film-forming foam (AFFFs) and leaching of leachate from landfill (30.2%). The adsorption of PFAAs by soil is mainly influenced by soil pH, ionic strength, soil organic matter and minerals. The concentrations of perfluoroalkyl carboxylic acids (PFCAs) in soil are negatively correlated with the length of carbon chain, log K_ow, and log K_oc. The carbon chain lengths of PFAAs are negatively correlated with the root-soil concentration factors (RCFs) and shoot-soil concentration factors (SCFs). The uptake of PFAAs by plant is influenced by physicochemical properties of PFAAs, plant physiology and soil environment. Further studies should be conducted to make up the inadequacy of existing knowledge on the behavior and fate of PFAAs in soil-plant system.

Metabolic perturbations in pregnant rats exposed to low-dose perfluorooctanesulfonic acid: An integrated multi-omics analysis

Emerging epidemiological evidence has linked per- and polyfluoroalkyl substances (PFAS) exposure could be linked to the disturbance of gestational glucolipid metabolism, but the toxicological mechanism is unclear, especially when the exposure is at a low level. This study examined the glucolipid metabolic changes in pregnant rats treated with relatively low dose perfluorooctanesulfonic acid (PFOS) through oral gavage during pregnancy [gestational day (GD): 1-18]. We explored the molecular mechanisms underlying the metabolic perturbation. Oral glucose tolerance test (OGTT) and biochemical tests were performed to assess the glucose homeostasis and serum lipid profiles in pregnant Sprague-Dawley (SD) rats randomly assigned to starch, 0.03 and 0.3 mg/kg·bw·d groups. Transcriptome sequencing combined with non-targeted metabolomic assays were further performed to identify differentially altered genes and metabolites in the liver of maternal rats, and to determine their correlation with the maternal metabolic phenotypes. Results of transcriptome showed that differentially expressed genes at 0.03 and 0.3 mg/kg·bw·d PFOS exposure were related to several metabolic pathways, such as peroxisome proliferator-activated receptors (PPARs) signaling, ovarian steroid synthesis, arachidonic acid metabolism, insulin resistance, cholesterol metabolism, unsaturated fatty acid synthesis, bile acid secretion. The untargeted metabolomics identified 164 and 158 differential metabolites in 0.03 and 0.3 mg/kg·bw·d exposure groups, respectively under negative ion mode of Electrospray Ionization (ESI-), which could be enriched in metabolic pathways such as α-linolenic acid metabolism, glycolysis/gluconeogenesis, glycerolipid metabolism, glucagon signaling pathway, glycine, serine and threonine metabolism. Co-enrichment analysis indicated that PFOS exposure may disturb the metabolism pathways of glycerolipid, glycolysis/gluconeogenesis, linoleic acid, steroid biosynthesis, glycine, serine and threonine. The key involved genes included down-regulated Ppp1r3c and Abcd2, and up-regulated Ogdhland Ppp1r3g, and the key metabolites such as increased glycerol 3-phosphate and lactosylceramide were further identified. Both of them were significantly associated with maternal fasting blood glucose (FBG) level. Our findings may provide mechanistic clues for clarifying metabolic toxicity of PFOS in human, especially for susceptible population such as pregnant women.

Effects of perfluorooctanoic acid on endoplasmic reticulum stress and lipid metabolism-related genes in human pancreatic cells

Perfluorooctanoic acid (PFOA) is environmentally persistent and has been classified by The International Cancer Research Agency (IARC) as a possible human pancreatic carcinogen. In this study, the epigenetic alteration, the changes in the expression levels of endoplasmic reticulum stress-related and metabolism-related genes, as well as DNA methyltransferase expression were investigated using RT-PCR and ELISA assays. PFOA induced a significant increase in the methylation ratio (5-mC%), impacted DNA methylation maintenance gene expression and decreased lipid metabolism-related genes except for PPARγ (≥ 13-fold increase). While PFOA induced the expression of ATF4 (≥ 5.41-folds), CHOP (≥ 5.41-folds) genes, it inhibited the expression of ATF6 (≥ 67.2%), GRP78 (≥ 64.3%), Elf2α (≥ 95.8%), IRE1 (≥ 95.5%), and PERK (≥ 91.7%) genes. It is thought that epigenetic mechanisms together with disruption in the glucose-lipid metabolism and changes in endoplasmic reticulum stress-related genes may play a key role in PFOA-induced pancreatic toxicity.

GPX2 Gene Affects Feed Efficiency of Pigs by Inhibiting Fat Deposition and Promoting Muscle Development

GPX2 has been recognized as a potential candidate gene for feed efficiency in pigs. This article aimed to elucidate polymorphism of GPX2 associated with feed efficiency and its related molecular mechanism. In this study, seven single nucleotide polymorphisms (SNP) of GPX2 were found among 383 Duroc pigs. In addition, seven SNPs and ALGA0043483 (PorcineSNP60 BeadChip data in 600 Duroc pigs), which are near the GPX2 gene, were identified in one haplotypes block. Furthermore, associated studies showed that the genotype of GPX2 has significant association with weaning weight and 100 kg BF in Duroc pigs. In addition, the AG had no effect when the backfat became thinner, and the FCR and RFI traits had a tendency to decrease in the G3 + TT combination genotype, accompanied by an increase of GPX2 expression in backfat and muscle tissues. At the cellular level, the adipocyte proliferation and ability of adipogenic differentiation were reduced, and the lipid degradation increased in 3T3-L1 when there was overexpression of GPX2. In contrast, overexpression of the GPX2 gene can promote the muscle cell proliferation and myogenic differentiation in C2C12 cells. In other words, GPX2 has the effect of reducing fat deposition and promoting muscle development, and it is a candidate gene for backfat and feed efficiency.

Associations of per- and polyfluoroalkyl substances (PFAS) and their mixture with oxidative stress biomarkers during pregnancy

BACKGROUND

Oxidative stress from excess reactive oxygen species (ROS) is a hypothesized contributor to preterm birth. Per- and polyfluoroalkyl substances (PFAS) exposure is reported to generate ROS in laboratory settings, and is linked to adverse birth outcomes globally. However, to our knowledge, the relationship between PFAS and oxidative stress has not been examined in the context of human pregnancy.

OBJECTIVE

To investigate the associations between prenatal PFAS exposure and oxidative stress biomarkers among pregnant people.

METHODS

Our analytic sample included 428 participants enrolled in the Illinois Kids Development Study and Chemicals In Our Bodies prospective birth cohorts between 2014 and 2019. Twelve PFAS were measured in second trimester serum. We focused on seven PFAS that were detected in >65 % of participants. Urinary levels of 8-isoprostane-prostaglandin-F2α, prostaglandin-F2α, 2,3-dinor-8-iso-PGF2α, and 2,3-dinor-5,6-dihydro-8-iso-PGF2α were measured in the second and third trimesters as biomarkers of oxidative stress. We fit linear mixed-effects models to estimate individual associations between PFAS and oxidative stress biomarkers. We used quantile g-computation and Bayesian kernel machine regression (BKMR) to assess associations between the PFAS mixture and averaged oxidative stress biomarkers.

RESULTS

Linear mixed-effects models showed that an interquartile range increase in perfluorooctane sulfonic acid (PFOS) was associated with an increase in 8-isoprostane-prostaglandin-F2α (β = 0.10, 95 % confidence interval = 0, 0.20). In both quantile g-computation and BKMR, and across all oxidative stress biomarkers, PFOS contributed the most to the overall mixture effect. The six remaining PFAS were not significantly associated with changes in oxidative stress biomarkers.

CONCLUSIONS

Our study is the first to investigate the relationship between PFAS exposure and biomarkers of oxidative stress during human pregnancy. We found that PFOS was associated with elevated levels of oxidative stress, which is consistent with prior work in animal models and cell lines. Future research is needed to understand how prenatal PFAS exposure and maternal oxidative stress may affect fetal development.

The effect of chronic exposure to a low concentration of perfluorooctanoic acid on cognitive function and intestinal health of obese mice induced by a high-fat diet

Perfluorooctanoic acid (PFOA) is a persistent organic pollutant associated with many adverse health risks. Evidence suggests that obese individuals may be more susceptible to environmental substances. In the present work, we explored the effects of PFOA exposure on the cognitive function and intestinal health of obese mice. Obese mice induced by a high-fat diet were exposed to PFOA (0.5 mg/kg (bw)/day) via drinking water for 100 days. After exposure to PFOA, decreased body weight, enlarged liver, abnormal behavior, impaired synapse structure, neuroinflammation, activated glial cell, decreased nerve growth factor, altered gut microbiota, and disturbed serum metabolites were observed, while the gut inflammation and intestinal barrier were not significantly influenced. These results suggest that exposure to PFOA is associated with cognitive impairment in obese mice.

Perfluorooctanoic acid affects mouse brain and liver tissue through oxidative stress

The aim of this study was to investigate oxidative stress induced by perfluorooctanoic acid (PFOA) in the brain and liver tissues of Balb/c mice as well as protective effects of taurine and coenzyme Q₁₀ (CoQ₁₀) in both organs. For this purpose, animals were treated with PFOA (15 and 30 mg/kg) orally and their lipid peroxidation, total glutathione levels (GSH), and antioxidant enzyme activities measured and both tissues analysed for histopathological changes. Our results showed a dose-dependent decrease in body weight and increase in relative brain and liver weights, PFOA-induced lipid peroxidation and reduced glutathione peroxidase (GPx) activity in the brain tissue, and changes in GSH levels, GPx, superoxide dismutase (Cu-Zn SOD), and catalase (CAT) activities in the liver tissue. Pre-treatment with taurine or CoQ₁₀ provided protection against PFOA-induced Cu-Zn SOD reduction in the liver tissue. Our findings evidence the depleting effect of PFOA on antioxidative systems and confirm that PFOA exerts its (neuro)toxicity through oxidative stress, but further research is needed to identify the exact toxicity mechanisms, especially in the brain.

Exposure to perfluorooctanoic acid leads to promotion of pancreatic cancer

Pancreatic cancer is the fourth leading cause of cancer deaths in the United States. Perfluorooctanoic acid (PFOA), a persistent environmental pollutant, has been shown to induce pancreatic acinar cell tumors in rats. Human epidemiologic studies have linked PFOA exposure to adverse chronic health effects including several types of cancer. Previously, we demonstrated that PFOA induces oxidative stress and focal ductal hyperplasia in the mouse pancreas. Here, we evaluated whether PFOA promotes pancreatic cancer using the LSL-KRasG12D;Pdx-1 Cre (KC) mouse model of pancreatic cancer. KC mice were exposed to 5 ppm PFOA in drinking water starting at 8 weeks of age and analyzed at 6 and 9 months of age. At the 6-month time point, PFOA exposure increased pancreatic intraepithelial neoplasia (PanIN) area by 58%, accompanied by a 2-fold increase in lesion number. Although PanIN area increased at 9 months, relative to 6 months, no treatment effect was observed. Collagen deposition was enhanced by PFOA at both the 6- and 9-month time points. PFOA also induced oxidative stress in the pancreas evidenced by elevated antioxidant activity of superoxide dismutase (Sod), catalase and thioredoxin reductase, and a ~3-fold increase in Sod1 mRNA and protein levels at 6 months. Although antioxidant activity was not enhanced by PFOA exposure at the 9-month time point, increased pancreatic oxidative damage was observed. Collectively, these results show that PFOA elicited temporal increases in PanIN lesion area and desmoplasia concomitant with the induction of oxidative stress, demonstrating that it functions to promote pancreatic cancer progression.

Exposure to perfluorooctane sulfonate reduced cell viability and insulin release capacity of β cells

Per- and polyfluoroalkyl substances (PFAS) are found to have multiple adverse outcomes on human health. Recently, epidemiological and toxicological studies showed that exposure to PFAS had adverse impacts on pancreas and showed association with insulin abnormalities. To explore how PFAS may contribute to diabetes, we studied impacts of perfluorooctane sulfonate (PFOS) on cell viability and insulin release capacity of pancreatic β cells by using in vivo and in vitro methods. We found that 28-day administration with PFOS (10 mg/(kg body weight•day)) caused reductions of pancreas weight and islet size in male mice. PFOS administration also led to lower serum insulin level both in fasting state and after glucose infusion among male mice. For cell-based in vitro bioassay, we used mouse β-TC-6 cancer cells and found 48-hr exposure to PFOS decreased the cell viability at 50 μmol/L. By measuring insulin content in supernatant, 48-hr pretreatment of PFOS (100 μmol/L) decreased the insulin release capacity of β-TC-6 cells after glucose stimulation. Although these concentrations were higher than the environmental concentration of PFOS, it might be reasonable for high concentration of PFOS to exert observable toxic effects in mice considering mice had a faster removal efficiency of PFOS than human. PFOS exposure (50 μmol/L) to β-TC-6 cells induced intracellular accumulation of reactive oxidative specie (ROS). Excessive ROS induced the reactive toxicity of cells, which eventually invoke apoptosis and necrosis. Results in this study provide evidence for the possible causal link of exposure to PFOS and diabetes risk.

Persistent organic pollutants and β-cell toxicity: a comprehensive review

Persistent organic pollutants (POPs) are a diverse family of contaminants that show widespread global dispersion and bioaccumulation. Humans are continuously exposed to POPs through diet, air particles, and household and commercial products; POPs are consistently detected in human tissues, including the pancreas. Epidemiological studies show a modest but consistent correlation between exposure to POPs and increased diabetes risk. The goal of this review is to provide an overview of epidemiological evidence and an in-depth evaluation of the in vivo and in vitro evidence that POPs cause β-cell toxicity. We review evidence for six classes of POPs: dioxins, polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), organophosphate pesticides (OPPs), flame retardants, and per- and polyfluoroalkyl substances (PFAS). The available data provide convincing evidence implicating POPs as a contributing factor driving impaired glucose homeostasis, β-cell dysfunction, and altered metabolic and oxidative stress pathways in islets. These findings support epidemiological data showing that POPs increase diabetes risk and emphasize the need to consider the endocrine pancreas in toxicity assessments. Our review also highlights significant gaps in the literature assessing islet-specific endpoints after both in vivo and in vitro POP exposure. In addition, most rodent studies do not consider the impact of biological sex or secondary metabolic stressors in mediating the effects of POPs on glucose homeostasis and β-cell function. We discuss key gaps and limitations that should be assessed in future studies.

Early Warnings by Liver Organoids on Short- and Long-Chain PFAS Toxicity

Short-chain per-fluoroalkyl substances (PFAS) have replaced long-chains in many applications, however the toxicity and its mode of action and interactions due to the large number of these compounds and their mixtures is still poorly understood. The paper aims to compare the effects on mouse liver organoids (target organ for bioaccumulation) of two long-chain PFAS (perfluorooctane sulfonate -PFOS-, perfluorooctanoic acid -PFOA) and two short-chain PFAS commonly utilized in the industry (heptafluorobutyric acid -HFBA-, Pentafluoropropionic anhydride-PFPA) to identify the mode of action of these classes of contaminants. Cytomorphological aberrations and ALT/GDH enzyme disruption were identified but no acute toxicity endpoint neither apoptosis was detected by the two tested short-chain PFAS. After cytomorphological analysis, it is evident that short-chain PFAS affected organoid morphology inducing a reduction of cytostructural complexity and aberrant cytological features. Conversely, EC50 values of 670 ± 30 µM and 895 ± 7 µM were measured for PFOS and PFOA, respectively, together with strong ALT/GDH enzyme disruption, caspase 3 and 7 apoptosis activation and deep loss of architectural complexity of organoids in the range of 500–1000 µM. Eventually, biochemical markers and histology analysis confirmed the sensitivity of organoid tests that could be used as a fast and reproducible platform to test many PFAS and mixtures saving time and at low cost in comparison with in vivo tests. Organoids testing could be introduced as an innovative platform to assess the toxicity to fast recognize potentially dangerous pollutants.

Increased Oxidative Stress in Gastric Cancer Patients and Their First-Degree Relatives: A Prospective Study from Northeastern Brazil

Background and Aims

First-degree relatives of gastric cancer patients are at increased risk of developing gastric cancer. Increased oxidative stress, including lipid peroxidation, has been associated with gastric carcinogenesis. Whether first-degree relatives of gastric cancer patients have increased oxidative stress remains unknown. We aimed to compare oxidative stress in patients with gastric cancer, their first-degree relatives, and dyspeptic controls.

Methods

A total of 155 patients undergoing upper endoscopy were prospectively enrolled, including 50 with gastric cancer, 49 first-degree relatives of gastric cancer patients, and 56 controls. Serum concentrations of malondialdehyde (MDA) and glutathione) and activities of superoxide dismutase (SOD) and catalase were measured. Multivariate analysis adjusting for sex, age, smoking status, and alcohol consumption was performed.

Results

Lipid peroxidation, as measured by concentration of MDA (nmol/mL), was higher (p = 0.04), and glutathione levels were lower (p < 0.001) in the gastric cancer group compared to controls. There was no difference in the catalase activity among the groups. There was no difference in glutathione and MDA concentration or catalase activity between the different stages of gastric cancer based on the TNM classification. Relatives of gastric cancer patients had higher glutathione concentration (μmol/mL) compared to gastric cancer patients (262.5 vs. 144.6; p = 0.018), while there was no difference in MDA concentration. Catalase and superoxide dismutase activity were lower in the gastric cancer group (3.82 vs. 0.91; p < 0.001 and 1.04 vs. 0.6; p < 0.001) compared to their first-degree relatives. Interestingly, MDA concentration in the first-degree relative group was higher than in the control group (7.9 vs. 5.1; p = 0.03).

Conclusions

In this study, similarly to gastric cancer patients, their first-degree relatives were found to have increased oxidative stress compared to controls. Further studies are warranted to validate this observation and to better understand the role of oxidative stress as a possible biomarker in this population.

Associations between Exposures to Perfluoroalkyl Substances and Diabetes, Hyperglycemia, or Insulin Resistance: A Scoping Review

Per- and polyfluoroalkyl substances (PFASs) are persistent environmental pollutants that are commonly found in the human body due to exposures via drinking water, surfactants used in consumer materials, and aqueous film-forming foams (AFFFs). PFAS exposure has been linked to adverse health effects such as low infant birth weights, cancer, and endocrine disruption, though increasingly studies have demonstrated that they may perturb metabolic processes and contribute to dysfunction. This scoping review summarizes the chemistry of PFAS exposure and the epidemiologic evidence for associations between exposure to per- and polyfluoroalkyl substances and the development of diabetes, hyperglycemia, and/or insulin resistance. We identified 11 studies on gestational diabetes mellitus, 3 studies on type 1 diabetes, 7 studies on type 2 diabetes, 6 studies on prediabetes or unspecified diabetes, and 15 studies on insulin resistance or glucose tolerance using the SCOPUS and PubMed databases. Approximately 24 reported positive associations, 9 negative associations, 2 non-linear associations, and 2 inverse associations, and 8 reported no associations found between PFAS and all diabetes search terms. Cumulatively, these data indicate the need for further studies to better assess these associations between PFAS exposure and diabetes.

Exposure to isomers of per- and polyfluoroalkyl substances increases the risk of diabetes and impairs glucose-homeostasis in Chinese adults: Isomers of C8 health project

Per- and polyfluoroalkyl substances (PFAS) exposure has been linked to diabetes, but evidence on the association of isomers of PFAS with type 2 diabetes (T2D) remains scant. This population based cross-sectional study aimed to investigate associations between serum PFAS isomers, glucose-homeostasis markers and T2D, adjusted for multiple potential confounders. We used data from "Isomers of C8 Health Project in China" from July 2015 to October 2016. A total of 10 PFAS including isomers of PFOS and PFOA were measured in serum of 1045 Chinese adults. Fasting blood glucose, fasting insulin, homeostasis model of insulin (HOMA-IR) and beta cell function (HOMA-β) were considered as markers of glucose-homeostasis. We found significant positive associations between serum PFAS isomers and glucose-homeostasis markers, namely, fasting blood glucose, fasting insulin and HOMA-IR. Per log-unit increase in branched (br)-PFOS concentration was associated with increased fasting blood glucose (β = 0.25, 95% CI: 0.18, 0.33), fasting insulin (β = 2.19, 95% CI: 1.44, 2.93) and HOMA-IR (β = 0.69, 95% CI: 0.50, 0.89). As compared to br-PFOS, linear (n)-PFOS and -PFOA showed lesser significant associations with glucose-homeostasis makers. Further, exposure to all PFAS including isomeric PFOS, PFOA and PFHxS increased the risk of T2D with br-PFOS exhibiting the highest risk (OR = 5.41, 95% CI: 3.68-7.96). The associations were stronger among women than men. In conclusion, chronic exposure to PFAS isomers was associated with impaired glucose-homeostasis and may increase the prevalence of T2D in Chinese adults. Given the ubiquity of PFAS in the environment and the public health burden of T2D, future studies are warranted to corroborate the findings.

N-acetyl cysteine co-treatment abates perfluorooctanoic acid-induced reproductive toxicity in male rats

Perfluorooctanoic acid is a synthetic perfluoroalkyl-persistent in the environment and toxic to humans. N-acetylcysteine is a pro-drug of both amino acid l-cysteine and glutathione-a non-enzymatic antioxidant. N-acetylcysteine serves as an antidote for paracetamol poisoning and alleviates cellular oxidative and inflammatory stressors. We investigated N-acetylcysteine role against reproductive toxicity in male Wistar rats (weight: 140-220 g; 10 weeks old) posed by perfluorooctanoic acid exposure. Randomised rat cohorts were dosed both with perfluorooctanoic acid (5 mg/kg; p.o) or co-dosed with N-acetylcysteine (25 and 50 mg/kg p.o) for 28 days. Sperm physiognomies, biomarkers of testicular function and reproductive hormones, oxidative stress and inflammation were evaluated. Co-treatment with N-acetylcysteine significantly (p < .05) reversed perfluorooctanoic acid-mediated decreases in reproductive enzyme activities, and adverse effect on testosterone, luteinising and follicle-stimulating hormone concentrations. N-acetylcysteine treatment alone, improved sperm motility, count and viability, and reduced total sperm abnormalities. Co-treatment with N-acetylcysteine mitigated perfluorooctanoic acid-induced alterations in sperm function parameters. N-acetylcysteine abated (p < .05) perfluorooctanoic acid-induced oxidative stress in experimental rats testes and epididymis, and generally improved antioxidant enzyme activities and cellular thiol levels. Furthermore, N-acetylcysteine suppressed inflammatory responses and remedied perfluorooctanoic acid-mediated histological injuries in rat. Cooperatively, N-acetylcysteine enhanced reproductive function in perfluorooctanoic acid dosed rats, by lessening oxidative and nitrative stressors and mitigated inflammatory responses in the examined organ.

Legacy and Emerging Per- and Polyfluoroalkyl Substances: Analytical Techniques, Environmental Fate, and Health Effects

Due to their unique chemical properties, per- and polyfluoroalkyl substances (PFAS) have been used extensively as industrial surfactants and processing aids. While several types of PFAS have been voluntarily phased out by their manufacturers, these chemicals continue to be of ecological and public health concern due to their persistence in the environment and their presence in living organisms. Moreover, while the compounds referred to as “legacy” PFAS remain in the environment, alternative compounds have emerged as replacements for their legacy predecessors and are now detected in numerous matrices. In this review, we discuss the historical uses of PFAS, recent advances in analytical techniques for analysis of these compounds, and the fate of PFAS in the environment. In addition, we evaluate current biomonitoring studies of human exposure to legacy and emerging PFAS and examine the associations of PFAS exposure with human health impacts, including cancer- and non-cancer-related outcomes. Special focus is given to short-chain perfluoroalkyl acids (PFAAs) and ether-substituted, polyfluoroalkyl alternatives including hexafluoropropylene oxide dimer acid (HFPO-DA; tradename GenX), 4,8-dioxa-3H-perfluorononanoic acid (DONA), and 6:2 chlorinated polyfluoroethersulfonic acid (6:2 Cl-PFESA; tradename F-53B).

PFAS Environmental Pollution and Antioxidant Responses: An Overview of the Impact on Human Field

Due to their unique properties, perfluorinated substances (PFAS) are widely used in multiple industrial and commercial applications, but they are toxic for animals, humans included. This review presents some available data on the PFAS environmental distribution in the world, and in particular in Europe and in the Veneto region of Italy, where it has become a serious problem for human health. The consumption of contaminated food and drinking water is considered one of the major source of exposure for humans. Worldwide epidemiological studies report the negative effects that PFAS have on human health, due to environmental pollution, including infertility, steroid hormone perturbation, thyroid, liver and kidney disorders, and metabolic disfunctions. In vitro and in vivo researches correlated PFAS exposure to oxidative stress effects (in mammals as well as in other vertebrates of human interest), produced by a PFAS-induced increase of reactive oxygen species formation. The cellular antioxidant defense system is activated by PFAS, but it is only partially able to avoid the oxidative damage to biomolecules.

Effects of per- and poly-fluorinated alkyl substances on pancreatic and endocrine differentiation of human pluripotent stem cells

Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) are typical per- and poly-fluorinated alkyl substances (PFASs) that epidemiological studies have already associated with diabetes. However, insufficient data on their toxicity have been reported to explain any mechanism of action, which could justify such an association. Meanwhile, short-chain PFASs designed to substitute PFOA and PFOS, have already raised increasing concerns for their biosafety. Here, we evaluated whether common PFASs affected pancreatic and endocrine cell development using a human pluripotent stem cell pancreatic induction model and human pancreatic progenitor cell (hPP) endocrine induction model. The short-chain PFASs, pentafluorobenzoic acid, perfluorohexanoic acid, perfluorobutanesulfonic acid, and perfluorohexanesulfonic acid, homologous to PFOA or PFOS, did not significantly disrupt hPP generation, unlike PFOA and PFOS, based on pancreatic and duodenal homeobox 1 (PDX1) expression. However, SRY box 9 (SOX9) expression was suppressed in PDX1+ hPPs. All six PFASs did not disrupt SOX9 expression or hPP proliferation. However, endocrine differentiation of hPPs was affected, as indicated by neurogenin-3 (NGN3) downregulation, owing to abnormal increases in SOX9 and hairy and enhancer of split-1 (HES1) expressions. Thus, hyperactivation of NOTCH signaling was repressed after hPPs committed to the endocrine lineage. In conclusion, our study demonstrates how powerful human pluripotent stem cell-based pancreatic differentiation models can be in developmental toxicity evaluations, compared to traditional toxicity assays, mostly based on live animals. Moreover, our findings suggest that PFASs may alter pancreatic development after the pancreatic domain emerges from the gut tube, and provide insights into their toxicity mechanisms.

Serum Per- and Polyfluoroalkyl Substances Are Associated with Increased Hearing Impairment: A Re-Analysis of the National Health and Nutrition Examination Survey Data

Although studies have shown that per- and polyfluoroalkyl substances (PFAS) are potential environmental ototoxicants, epidemiologic study has been limited. I conducted a cross-sectional study to re-examine the associations between PFAS and hearing impairment. Data were obtained from the National Health and Nutrition Examination Survey (NHANES) 1999–2000, 2003-06, 2009-12, and 2015-16. Perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) were measured in serum samples. Participants were divided into quartiles for each PFAS. Air conduction pure-tone audiometry was administered. Hearing impairment (1: yes, 0: no) was defined as a hearing threshold of more than 25 dB at 500, 1000, 2000, 4000, and 8000 Hz in the worse ear. I assessed the relation of serum PFAS with hearing impairment by the generalized linear mixed model with a logit link and binary distribution. Tests for linear trend across quartiles of serum PFAS were conducted using the median serum PFAS in each quartile as a continuous variable. After adjusting for age, sex, body mass index, education, ethnicity group, and family income, I found positive correlations between PFOA and hearing impairment at 2000 Hz (p-trend < 0.01) and 3000 Hz (p-trend = 0.02); between PFOS and hearing impairment at 500 Hz (p-trend < 0.01), 2000 Hz (p-trend < 0.0001) and 3000 Hz (p-trend = 0.02); between PFNA and hearing impairment at 2000 Hz (p-trend = 0.05), 3000 Hz (p-trend < 0.01), 4000 Hz (p-trend = 0.02), and 8000 Hz (p-trend < 0.01); between PFHxS and hearing impairment at 500 Hz (p-trend = 0.04), 1000 Hz (p-trend = 0.03), and 2000 Hz (p-trend < 0.01). However, some of the findings were not significant when only comparing the highest with the lowest quartile of PFASs. In conclusion, several background serum PFASs are positively correlated with hearing impairment in the United States adult population.

Impact of Hurricane Maria on Drinking Water Quality in Puerto Rico

This study performed a comprehensive assessment of the impact of Hurricane Maria (HM) on drinking water quality in Puerto Rico (PR) by integrating targeted chemical analysis of both inorganic (18 trace elements) and organic trace pollutants (200 micropollutants) with high-throughput quantitative toxicogenomics and in vitro biomarkers-based toxicity assays. Average concentrations of 14 detected trace elements and 20 organic micropollutants showed elevation after HM. Arsenic, sucralose, perfluorooctanoic acid (PFOA), atrazine-2-hydroxy, benzotriazole, acesulfame, and prometon were at significantly (p < 0.05) higher levels in the post-HM than in the pre-HM samples. Thirteen micropollutants, including four pesticides, were only detected in posthurricane samples. Spatial comparison showed higher pollutant and toxicity levels in the samples from northern PR (where eight Superfund sites are located) than in those from southern PR. Distinctive pathway-specific molecular toxicity fingerprints for water extracts before and after HM and at different locations revealed changes in toxicity nature that likely resulted from the impact of HM on drinking water composition. Correlation analysis and Maximum Cumulative Ratio assessment suggested that metals (i.e., arsenic) and PFOA were the top ranked pollutants that have the potential to cause increased risk after HM, providing a possible direction for future water resource management and epidemiological studies.

Neurotoxicity of perfluorooctanoic acid and post-exposure recovery due to blueberry anthocyanins in the planarians Dugesia japonica

Perfluorooctanoic acid (PFOA) is a widely used synthetic industrial chemical which accumulates in ecosystems and organisms. Our study have investigated the neurobehavioral effects of PFOA and the alleviation effects of PFOA-induced neurotoxicity by blueberry anthocyanins (ANT) in Dugesia japonica. The planarians were exposed to PFOA and ANT for ten days. Researchs showed that exposure to PFOA affected locomotor behavior and ANT significantly alleviated the reduction in locomotion induced by PFOA. The regeneration of eyespots and auricles was suppressed by PFOA and was promoted by ANT. Following exposure to PFOA, acetylcholinesterase activity continually decreased and was unaffected in the ANT group, but was elevated after combined administration of PFOA and ANT. Oxidative DNA damage was found in planarians exposed to PFOA and was attenuated after administration of ANT by the alkaline comet assay. Concentrations of three neurotransmitters increased following exposure to PFOA and decreased after administration of ANT. Furthermore, ANT promoted and PFOA inhibited neuronal regeneration. DjotxA, DjotxB, DjFoxG, DjFoxD and Djnlg associated with neural processes were up-regulated following exposure to PFOA. Our findings indicate that PFOA is a neurotoxicant while ANT can attenuate these detrimental effects.

Perfluorooctanoic acid activates the unfolded protein response in pancreatic acinar cells

Perfluoroalkyl substances, such as perfluorooctanoic acid (PFOA), are widely used in consumer and industrial applications. Human epidemiologic and animal studies suggest that PFOA exposure elicits adverse effects on the pancreas; however, little is known about the biological effects of PFOA in this organ. In this study, we show that PFOA treatment of mouse pancreatic acinar cells results in endoplasmic reticulum (ER) stress and activation of the protein kinase-like endoplasmic reticulum kinase (PERK), inositol-requiring kinase/endonuclease 1α (IRE1α), and activating transcription factor 6 arms of the unfolded protein response (UPR) pathway. PFOA-stimulated activation of the UPR was blocked by pretreatment with specific PERK and IRE1α inhibitors and the chemical chaperone 4-phenyl butyrate, but not the antioxidants N-acetyl- l-cysteine and Tiron. PFOA treatment led to increased cytosolic Ca⁺² levels and induction of the UPR was blocked by an inhibitor of the inositol 1,4,5-trisphosphate receptor. These findings indicate that PFOA-induced ER stress may be the mechanistic trigger leading to oxidative stress in the pancreas.

Application of the Key Characteristics of Carcinogens to Per and Polyfluoroalkyl Substances

Per- and polyfluoroalkyl substances (PFAS) constitute a large class of environmentally persistent chemicals used in industrial and consumer products. Human exposure to PFAS is extensive, and PFAS contamination has been reported in drinking water and food supplies as well as in the serum of nearly all people. The most well-studied member of the PFAS class, perfluorooctanoic acid (PFOA), induces tumors in animal bioassays and has been associated with elevated risk of cancer in human populations. GenX, one of the PFOA replacement chemicals, induces tumors in animal bioassays as well. Using the Key Characteristics of Carcinogens framework for cancer hazard identification, we considered the existing epidemiological, toxicological and mechanistic data for 26 different PFAS. We found strong evidence that multiple PFAS induce oxidative stress, are immunosuppressive, and modulate receptor-mediated effects. We also found suggestive evidence indicating that some PFAS can induce epigenetic alterations and influence cell proliferation. Experimental data indicate that PFAS are not genotoxic and generally do not undergo metabolic activation. Data are currently insufficient to assess whether any PFAS promote chronic inflammation, cellular immortalization or alter DNA repair. While more research is needed to address data gaps, evidence exists that several PFAS exhibit one or more of the key characteristics of carcinogens.

Tissue distribution of 14C-labelled perfluorooctanoic acid in adult mice after 1-5 days of dietary exposure to an experimental dose or a lower dose that resulted in blood levels similar to those detected in exposed humans

Perfluorooctanoic acid (PFOA), a global environmental pollutant detected in both wildlife and human populations, has several pathophysiological effects in experimental animals, including hepatotoxicity, immunotoxicity, and developmental toxicity. However, details concerning the tissue distribution of PFOA, in particular at levels relevant to humans, are lacking, which limits our understanding of how humans, and other mammals, may be affected by this compound. Therefore, we characterized the tissue distribution of ¹⁴C-PFOA in mice in the same manner as we earlier examined its analogues perfluorooctanesulfonate (PFOS) and perfluorobutanesulfonate (PFBS) in order to allow direct comparisons. Following dietary exposure of adult male C57/BL6 mice for 1, 3 or 5 days to a low dose (0.06 mg/kg/day) or a higher experimental dose (22 mg/kg/day) of ¹⁴C-PFOA, both scintillation counting and whole-body autoradiography revealed the presence of PFOA in most of the 19 different tissues examined, demonstrating its ability to leave the bloodstream and enter tissues. There were no differences in the pattern of tissue distribution with the low and high dose and the tissue-to-blood ratios were similar. At both doses, PFOA levels were highest in the liver, followed by blood, lungs and kidneys. The body compartments estimated to contain the largest amounts of PFOA were the liver, blood, skin and muscle. In comparison with our identical studies on PFOS and PFBS, PFOA reached considerably higher tissue levels than PFBS, but lower than PFOS. Furthermore, the distribution of PFOA differed notably from that of PFOS, with lower tissue-to-blood ratios in the liver, lungs, kidneys and skin.

Astaxanthin reduces perfluorooctanoic acid cytotoxicity in Saccharomyces cerevisiae

Perfluorooctanoic acid (PFA) has been identified as an environmental contaminant of high concern for human health. In this study, we demonstrated that PFA induces a dose (0 to 1.5 mM) dependent cytotoxicity in S. cerevisiae cells which can be rescued by astaxanthin. The percent sensitivity induced by PFA and the cell protection offered by astaxanthin (30 μM) were demonstrated by CFU counts and spots. The increase in intracellular ROS, superoxide dismutase (SOD), glutathione and lipid peroxidation levels in PFA treated cells suggested that increased oxidative stress resulted in yeast cell death. In contrast, decreased ROS level, increased SOD activity, reduced glutathione and decreased lipid peroxidation by astaxanthin supplementation suggest that the cells are protected from the PFA induced oxidative stress mediated cytotoxicity. Reduced chromatin condensation and nuclear fragmentation in astaxanthin pre-treated cells indicate that astaxanthin rescued the cells from PFA induced apoptosis. Our overall results suggest that PFA induces oxidative stress-mediated cytotoxicity in yeast cells, which were rescued by astaxanthin treatment.

Associations of Perfluoroalkyl and Polyfluoroalkyl Substances With Incident Diabetes and Microvascular Disease

OBJECTIVE

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are suspected endocrine disruptors widely detected across populations. We examine the extent to which PFASs are associated with diabetes incidence and microvascular disease. Secondarily, we tested whether a lifestyle intervention modifies associations and decreases concentrations.

RESEARCH DESIGN AND METHODS

We analyzed data from a prospective cohort of 957 participants from the Diabetes Prevention Program (DPP) trial and Diabetes Prevention Program Outcomes Study (DPPOS). At baseline, participants were randomized to an intensive lifestyle intervention of diet, physical activity, and behavior modification or a placebo medication. We quantified plasma concentrations of six PFASs at baseline and 2 years after randomization. Participants were monitored for ∼15 years, repeatedly tested for diabetes, and evaluated for microvascular disease at the end of the follow-up.

RESULTS

A doubling in baseline branched perfluorooctanoic acid concentration was associated with a 14% increase in diabetes risk for the placebo (hazard ratio [HR] 1.14, 95% CI 1.04, 1.25) but not in the lifestyle intervention group (HR 1.01, 95% CI 0.92, 1.11, P interaction = 0.11). Mean change in plasma baseline branched perfluorooctanoic acid concentration was greater for the placebo (0.96 ng/mL; 95% CI 0.71, 1.22) compared with the lifestyle intervention group (0.31 ng/mL; 95% CI 0.14, 0.48) 2 years after randomization. Each doubling in N-ethyl-perfluorooctane sulfonamido acetic acid was associated with 17% greater odds of prevalent microvascular disease (OR 1.17, 95% CI 1.05, 1.31), and a similar association was observed for perfluorodimethylhexane sulfonic acid (OR 1.18, 95% CI 1.04, 1.35), regardless of treatment.

CONCLUSIONS

Some plasma PFASs were associated with diabetes and microvascular disease. Our results suggest that exercise and diet may attenuate the diabetogenic association of PFASs.

Fluorinated MRI contrast agents and their versatile applications in the biomedical field

MRI has been recognized as one of the most applied medical imaging techniques in clinical practice. However, the presence of background signal coming from water protons in surrounding tissues makes sometimes the visualization of local contrast agents difficult. To remedy this, fluorine has been introduced as a reliable perspective, thanks to its magnetic properties being relatively close to those of protons. In this review, we aim to give an overall description of fluorine incorporation in contrast agents for MRI. The different kinds of fluorinated probes such as perfluorocarbons, fluorinated dendrimers, polymers and paramagnetic probes will be described, as will their imaging applications such as chemical exchange saturation transfer (CEST) imaging, physico-chemical changes detection, drug delivery, cell tracking and inflammation or tumors detection.

Environmental ototoxicants, a potential new class of chemical stressors

Hearing loss is an injury that can develop over time, and people may not even be aware of it until it becomes a severe disability. Ototoxicants are substances that may damage the inner ear by either affecting the structures in the ear itself or by affecting the nervous system. We have examined the possibility that ototoxicants may present a health hazard in association with environmental exposures, adding to existing knowledge of their proven hazards under medical therapeutic conditions or occupational activities. In addition to the already described human environmental ototoxicants, mainly organochlorines such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), hexachlorocyclohexane (HCH) and hexachlorobenzene (HCB), we have examined the ubiquitous chemical stressors phthalates, bisphenol A/S/F/, PFCs, flame retardants (FRs) and cadmium for potential ototoxic properties, both as single substances or as chemical mixtures. Our literature review confirmed that these chemicals may disturb thyroid hormones homeostasis, activate aryl hydrocarbon receptor (AhR), and induce oxidative stress, which in turn may initiate a chain of events resulting in impairment of cochlea and hearing loss. With regard to auditory plasticity, diagnostics of a mixture of effects of ototoxicants, potential interactions of chemical and physical agents with effects on hearing, parallel deterioration of hearing due to chemical exposures and ageing, metabolic diseases or obesity, even using specific methods as brainstem auditory evoked potentials (BAEP) or otoacoustic emissions (OAEs) registration, may be difficult, and establishment of concentration-response relationships problematic. This paper suggests the establishment of a class of environmental oxotoxicants next to the established classes of occupational and drug ototoxicants. This will help to properly manage risks associated with human exposure to chemical stressors with ototoxic properties and adequate regulatory measures.

Perfluorooctanoic acid disrupts gap junction intercellular communication and induces reactive oxygen species formation and apoptosis in mouse ovaries

Perfluorooctanoic acid (PFOA) is a member of the perfluoroalkyl acid family of compounds. Due to the presence of strong carbon-fluorine bonds, it is practically nonbiodegradable and highly persistent in the environment. PFOA has been detected in the follicular fluid of women, and positively associated with reduced fecundability and infertility. However, there are no reports concerning the experimental evaluation of PFOA on oocyte toxicity in mammals. The aim of the present study was to determine if PFOA is able to induce oxidative stress in fetal ovaries and cause apoptosis in oocytes in vitro. In addition, since inhibition of the gap junction intercellular communication (GJIC) by PFOA has been demonstrated in liver cells in vivo and in vitro, the effect of PFOA on the GJIC between the oocyte and its supportive cumulus cells was studied. Results show that PFOA induced oocyte apoptosis and necrosis in vitro (medium lethal concentration, LC₅₀ = 112.8 μM), as evaluated with Annexin-V-Alexa 508 in combination with BOBO-1 staining. Reactive oxygen species (ROS) levels, as assessed by DCFH-DA, increased significantly in fetal ovaries exposed to ¼ LC₅₀ (28.2 μM, a noncytotoxic and relevant occupational exposure concentration) and LC₅₀ PFOA ex vivo. This perfluorinated compound also caused the blockage of GJIC in cumulus cells-oocyte complexes (COCs) obtained from female mice exposed in vivo, as evaluated by calcein transfer from cumulus cells to the oocyte. The ability of PFOA of disrupting the GJIC in COCs, generating ROS in the fetal ovary and causing apoptosis and necrosis in mammal's oocytes, might account for the reported association between increasing maternal plasma concentrations of PFOA with reduced fertility in women.

Higher plasma oxidative damage and lower plasma antioxidant defences in an Arctic seabird exposed to longer perfluoroalkyl acids

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) may cause detrimental effects on physiological function and reproduction of Arctic animals. However, there is a paucity of information on the link between PFASs and oxidative stress, which can have potential detrimental effects on key fitness traits, such as cellular homeostasis or reproduction. We have examined the correlations between multiple blood-based markers of oxidative status and several perfluoroalkyl acids (i.e., with 8 or more carbons) in male Arctic black-legged kittiwakes (Rissa tridactyla) during the pre-laying period. Higher protein oxidative damage was found in those birds having higher concentrations of perfluorododecanoic acid (PFDoA), perfluorotridecanoic acid (PFTriA) and perfluorotetradecanoic acid (PFTeA). Lower plasmatic non-enzymatic micro-molecular antioxidants were found in those birds having higher concentrations of perfluoroundecanoic acid (PFUnA), PFDoA and PFTeA. Effect size estimates showed that the significant correlations between PFASs and oxidative status markers were intermediate to strong. The non-enzymatic antioxidant capacity (including antioxidants of protein origin) was significantly lower in those birds having higher plasma concentration of linear perfluorooctanesulfonic acid (PFOSlin). In contrast, the activity of the antioxidant enzyme glutathione peroxidase in erythrocytes was not associated with any PFAS compounds. Our results suggest that increased oxidative stress might be one consequence of long-chain PFAS exposure. Experimental work will be needed to demonstrate whether PFASs cause toxic effects on free-living vertebrates through increased oxidative stress.

Characterizing the binding interactions of PFOA and PFOS with catalase at the molecular level

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have effects on human health by inducing oxidative stress and catalase (CAT) is a vital enzyme involved in protection against oxidative damage. The interactions of PFOA and PFOS with CAT were investigated by using biophysical methods including spectroscopic techniques, molecular docking and enzyme activity measurements. UV-visible, circular dichroism (CD) and resonance light scattering (RLS) spectroscopy results showed that the structure and conformation of CAT were changed by PFOA and PFOS. PFOA could loosen and unfold the skeleton of CAT but PFOS affected the microenvironment around the aromatic amino acid residues and heme groups. Both PFOA and PFOS altered the secondary structure of CAT by decreasing α-helix and increasing β-sheet content. The size of CAT was smaller and CAT became dispersed when it was bound by perfluorinated compounds (PFCs). Furthermore, enzyme activity test showed that PFOS decreased the activity of CAT because the binding site of PFOS was close to the active center of CAT, but PFOA had little effect on the activity because PFOA bound at the surface of the enzyme. These results indicated that PFCs could damage the structures and conformations of CAT but the changes were not always related to the activity and function of CAT.

Fluorinated Paramagnetic Complexes: Sensitive and Responsive Probes for Magnetic Resonance Spectroscopy and Imaging

Fluorine magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) of chemical and physiological processes is becoming more widespread. The strength of this technique comes from the negligible background signal in in vivo¹⁹F MRI and the large chemical shift window of ¹⁹F that enables it to image concomitantly more than one marker. These same advantages have also been successfully exploited in the design of responsive ¹⁹F probes. Part of the recent growth of this technique can be attributed to novel designs of ¹⁹F probes with improved imaging parameters due to the incorporation of paramagnetic metal ions. In this review, we provide a description of the theories and strategies that have been employed successfully to improve the sensitivity of ¹⁹F probes with paramagnetic metal ions. The Bloch-Wangsness-Redfield theory accurately predicts how molecular parameters such as internuclear distance, geometry, rotational correlation times, as well as the nature, oxidation state, and spin state of the metal ion affect the sensitivity of the fluorine-based probes. The principles governing the design of responsive ¹⁹F probes are subsequently described in a "how to" guide format. Examples of such probes and their advantages and disadvantages are highlighted through a synopsis of the literature.

Plasma Concentrations of Perfluoroalkyl Substances and Risk of Type 2 Diabetes: A Prospective Investigation among U.S. Women

BACKGROUND

Emerging evidence suggests that perfluoroalkyl substances (PFASs) are endocrine disruptors and may contribute to the etiology of type 2 diabetes (T2D), but this hypothesis needs to be clarified in prospective human studies.

OBJECTIVES

Our objective was to examine the associations between PFAS exposures and subsequent incidence of T2D in the Nurses' Health Study II (NHSII). In addition, we aimed to evaluate potential demographic and lifestyle determinants of plasma PFAS concentrations.

METHODS

A prospective nested case-control study of T2D was conducted among participants who were free of diabetes, cardiovascular disease, and cancer in 1995-2000 [(mean±SD): 45.3±4.4 y) of age]. We identified and ascertained 793 incident T2D cases through 2011 (mean±SD) years of follow-up: 6.7±3.7 y). Each case was individually matched to a control (on age, month and fasting status at sample collection, and menopausal status and hormone replacement therapy). Plasma concentrations of five major PFASs, including perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonate, perfluorononanoic acid, and perfluorodecanoic acid were measured. Odds ratios (ORs) of T2D by PFAS tertiles were estimated by conditional logistic regression.

RESULTS

Shorter breastfeeding duration and higher intake of certain foods, such as seafood and popcorn, were significantly associated with higher plasma concentrations of PFASs among controls. After multivariate adjustment for T2D risk factors, including body mass index, family history, physical activity, and other covariates, higher plasma concentrations of PFOS and PFOA were associated with an elevated risk of T2D. Comparing extreme tertiles of PFOS or PFOA, ORs were 1.62 (95% CI: 1.09, 2.41; p_trend=0.02) and 1.54 (95% CI: 1.04, 2.28; p_trend=0.03), respectively. Other PFASs were not clearly associated with T2D risk.

CONCLUSIONS

Background exposures to PFASs in the late 1990s were associated with higher T2D risk during the following years in a prospective case-control study of women from the NHSII. These findings support a potential diabetogenic effect of PFAS exposures. https://doi.org/10.1289/EHP2619.

Environmental Toxicant Exposures and Type 2 Diabetes Mellitus: Two Interrelated Public Health Problems on the Rise

Rates of type 2 diabetes mellitus (T2DM) are rising rapidly across the globe and the impact of this devastating disease threatens to plague the 21^st century. While some contributing factors are well-recognized (e.g. sedentary lifestyles and caloric excess), others diabetes-promoting risk factors are less established or poorly appreciated. The latter category includes environmental exposures to diabetogenic contaminants. Herein we review some of the latest concepts and mechanisms by which environmental exposures may contribute to rising rates of T2DM with a particular focus on mechanisms involving mitochondrial dysfunction and imbalances in reactive oxygen species (ROS). Furthermore, while the pathogenesis of diabetes includes impairments in insulin sensitivity as well as insulin secretion, we will specifically delve into the links between environmental exposures to toxicants such as arsenic and disruptions in insulin release from pancreatic β-cells. Since β-cell death or dysfunction lies at the heart of both T2DM as well as type 1 diabetes mellitus (T1DM), environmental endocrine disrupting chemicals (EDCs) that disrupt the production or regulated release of the glucose-lowering hormone insulin are likely contributors to diabetes risk. Importantly, understanding the contribution of toxicants to diabetes risk as well as improved understanding of their mechanisms of action offer unique opportunities to modulate diabetes risk via targeted therapeutics or public policy interventions to reduce and remediate exposures.

Evaluation of single and joint toxicity of perfluorooctane sulfonate and zinc to Limnodrilus hoffmeisteri: Acute toxicity, bioaccumulation and oxidative stress

Perfluorooctane sulfonate (PFOS) and zinc have been detected in aquatic environment widely. In order to study the combined effects of PFOS and Zn, a series of experiments was conducted to explore the acute mortality, bioaccumulation and antioxidant status of Limnodrilus hoffmeisteri. The acute toxicity was evaluated by calculating 24h-EC50 values, and it was observed that 24h-EC50 values in single and joint treatments decreased with decreasing pH value or increasing exposure concentration. Toxic unit analysis suggested that the combined effects of the PFOS+Zn binary mixture were mostly simple addition, with 8 groups showing synergism and only one group showing antagonism. The analysis of internal Zn and PFOS concentration showed that the possible interaction between Zn and PFOS can affect the bioaccumulation of the two chemicals in L. hoffmeisteri. In addition, oxidative stress status was assessed by measuring oxidation-related biochemical parameters such as superoxide dismutase, glutathione peroxidase and malondialdehyde, and the integrated biomarker response index was estimated to rank the toxicity order. Exposures to Zn and PFOS were found to evoke some changes in the antioxidant defense system, and a strong self-adaptive ability was noticed for L. hoffmeisteri after 10 d exposure.

A randomized, controlled trial of the effect of rilpivirine versus efavirenz on cardiovascular risk in healthy volunteers

OBJECTIVES

The HIV NNRTI rilpivirine is being evaluated as a possible agent for HIV pre-exposure prophylaxis. We have recently shown that the NNRTI efavirenz may impair endothelial function assessed as flow-mediated dilation (FMD), but whether this impairment is also found with rilpivirine is unknown. We sought to compare cardiovascular risk profiles between efavirenz and rilpivirine in healthy volunteers.

METHODS

We performed a prospective, randomized, open-label trial in 40 HIV-uninfected healthy volunteers who were randomized 1: 1 to either efavirenz or rilpivirine. Vascular indices, metabolic parameters, inflammatory biomarkers and oxidative stress were measured before and after 4 weeks of treatment. This study is registered at ClinicalTrials.gov (NCT01585038).

RESULTS

There were no significant differences in 4 week mean (SD) changes in FMD between efavirenz and rilpivirine [0.089 (3.65)% versus 0.63 (2.42)%; P = 0.77]. There were also no significant differences in 4 week changes in high-sensitivity C-reactive protein, IL-6, soluble vascular cell adhesion molecule-1, HDL-cholesterol, triglycerides or homeostasis model assessment-insulin resistance. However, efavirenz led to significant increases in total cholesterol [19.39 (23.9) versus -5.78 (16.5) mg/dL; P < 0.001], LDL-cholesterol [13.29 (19.5) versus -2.24 (13.4) mg/dL; P = 0.009] and F2-isoprostanes [92.7 (178.6) versus -101.4 (215.7) pg/mL; P = 0.019] compared with rilpivirine. Two participants from each study group discontinued prematurely for adverse events.

CONCLUSIONS

There were no significant differences in the changes in endothelial function over 1 month between the efavirenz and rilpivirine groups, although efavirenz had worse lipid changes compared with rilpivirine. Longer-term studies are required for confirmation.