Serum perfluoroalkyl substances (PFAS) and risk of asthma and various allergies in adolescents. The Tromsø study Fit Futures in Northern Norway

Exposure to per-and poly-fluoroalkyl substances and respiratory and skin effects in children and adolescents: A systematic review and meta-analysis

Despite being previously banned due to long-term health effects, Per- and polyfluoroalkyl substances (PFAS) remain widespread in the environment, accumulating in animals and humans. This systematic review and meta-analysis explores associations between exposure to PFAS and asthma onset, wheezing, atopic dermatitis, and eczema in children and adolescents while addressing exposure timing and sex-specific differences. After comprehensive search conducted in several databases, including risk of bias, study heterogeneity, and quality of evidence evaluation, the review included 28 observational studies, most with low risk of bias in all domains. PFAS exposure was not significantly associated with asthma onset (OR:1.03, CI:0.99;1.07), but revealed significantly lower association in the prenatal period (OR:0.97, CI:0.94;0.99), higher in the postnatal period (OR:1.20, CI:1.07;1.35), and no differences among sexes. PFAS exposure (mainly prenatal) was associated with 4 % significantly lower odds of wheezing (OR:0.96, CI:0.94;0.98), higher in girls (OR:0.94, CI:0.91;0.98) than in boys (OR:0.97, CI:0.94;1.00). No significant impact was noted on atopic dermatitis (OR:1.04, CI:0.94;1.16), while PFAS exposure was associated with 8 % significantly lower eczema odds (OR:0.92, CI:0.89;0.96). Evidence was insufficient to perform sensitivity analyses on atopic dermatitis and eczema. Additional research is needed on the impact of synergistic and co-exposure to other pollutants on children and adolescents' health.

Integrated PBPK Modelling for PFOA Exposure and Risk Assessment

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

Per- and polyfluoroalkyl substances (PFAS): immunotoxicity at the primary sites of exposure

Per- and polyfluoroalkyl substances (PFAS) are persistent synthetic chemicals widely used in industrial and consumer products, leading to environmental contamination and human exposure. This review focuses on perfluoroalkyl acids, a subset of PFAS, which are primarily encountered through diet, including drinking water, and other pathways such as dust ingestion, and dermal contact. Impaired vaccine antibody response has been identified as the most critical effect for risk assessment by the European Food Safety Authority. Furthermore, human epidemiological studies have linked exposure to certain PFAS to various immune-related outcomes, such as asthma, allergies, and inflammatory bowel disease. This review examines potential immunomodulatory effects of perfluoroalkyl acids at the primary sites of exposure: lungs, intestines, and skin, using human epidemiological data as the basis for investigating these impacts. While animal studies are referenced for context, this paper highlights the need for further human-based research to address key questions about PFAS and their immunological impacts. The state of in vitro toxicity testing related to these effects is thoroughly reviewed and critical issues pertaining to this topic are discussed.

Respiratory Health Impacts from Natural Disasters and Other Extreme Weather Events: The Role of Environmental Stressors on Asthma and Allergies

PURPOSE OF REVIEW

The frequency of natural disasters, other extreme weather events, and downstream emissions of emerging contaminants is increasing. One category of health outcome that is now experiencing increased prevalence due to these environmental threats is respiratory disease, specifically asthma and allergies; though a review summarizing current knowledge and research gaps has not been synthesized on this topic in recent years despite growing evidence.

RECENT FINDINGS

We identified recent literature that connects allergy/asthma with environmental events that are increasing in prevalence alongside natural disasters and other extreme weather events, including algal blooms, floods, heat stress, wildfires, and thunderstorms. Coinciding emissions of per-and polyfluoroalkyl substances (PFAS) and microplastics (MPs) are also discussed as downstream outcomes of these environmental events. Available evidence ranged according to environmental event/stressor type, with over 50 papers identified as relevant to this research scope in the last five years. Narrative synthesis of these papers highlighted exposure-disease linkages for stressors related to natural disasters, other extreme weather events, and downstream emissions of emerging contaminants with pulmonary asthma and allergy outcomes. Underlying biological mechanisms are beginning to be elucidated and include widespread inflammation in the lungs and changes in immune cell signaling and function across the pulmonary system. Take home points in this review pave the way for future investigations to better understand the impacts of these environmental events amongst the complex milieu of threats becoming increasingly prevalent worldwide.

Complete Aqueous Defluorination of GenX (Hexafluoropropylene Oxide Dimer Acid Anion) by Pulsed Electrolysis with Polarity Reversal

Per- and polyfluoroalkyl substances (PFAS) are extremely stable chemicals that are essential for modern life and decarbonization technologies. Yet PFAS are persistent pollutants that are harmful to human health. Hexafluoropropylene oxide dimer acid (GenX), a replacement for the PFAS chemical perfluorooctanoic acid, continues to pollute waterways. In this study, we report the complete defluorination of GenX through electrocatalysis in aqueous LiOH electrolytes, utilizing high surface area anodes consisting of pulsed laser in liquid synthesized [NiFe]-(OH)₂ nanocatalysts on hydrophilic carbon fiber paper. Additional experiments with industrial nickel-iron alloy demonstrated exceptional stability for >100 hours. Including a brief interval of reversed polarity in pulsed electrolysis and optimizing the pulse train sequence enabled the complete defluorination of GenX. Our facile approach employs only nonprecious materials, does not require bisulfate or other auxiliary chemical agents that are consumed, and thus provides a promising strategy for alleviating the environmental impact of PFAS pollutants.

Incidence of respiratory diseases associated with per- and polyfluoroalkyl substances (PFAS) in PM2.5: New evidence from a population-based survey of Pearl River Delta (PRD), China

Epidemiological studies have evinced that particulate matter (PM) is linked to respiratory diseases, but the relationship between the specific constituents of PM and respiratory diseases remains scarce. Here, we evaluated the relationship between PFAS in PM2.5 with respiratory diseases. In this study, from May 2016 to May 2018, we recruited 131,346 school-aged children and adolescents living in Pearl River Delta, Guangdong Province, China. Participants self-reported the respiratory diseases, including asthma, wheezing, phlegm, cough and rhinitis. Logistic regression and qg-comp models were used to analyze the relationship between PFAS exposure and respiratory diseases. We found several PFAS were significantly associated with higher prevalence of respiratory diseases. For instance, higher quintiles of PFSA exposure (Q2-Q4), as compared to Q1, were associated with greater odds of respiratory diseases: 1.35 (95 %CI: 1.23, 1.48) in Q2, 1.95 (95 %CI: 1.78, 2.14) in Q3 and 2.83 (95 %CI: 2.76, 3.11) in Q4. Furthermore, qg-comp model analysis revealed PFCA as the most important weight in respiratory diseases. Moreover, the effect estimates were higher in boys, older children (>12 years old) and overweight/obesity, indicating the vulnerability of these subpopulations. In summary, exposure to PFAS, a specific PM2.5 constituent, potentially increases the risk of respiratory diseases among school-aged children and adolescents.

Perfluorooctane sulfonate attenuates IgE/Ag-stimulated mast cell activation and anaphylactic responses via activating SHP-1 pathway

Perfluorooctane sulfonate (PFOS), a widely distributed and persistent organic pollutant, is known to cause immune dysfunction. In a previous study, we reported that PFOS modestly increases mast cell activation. However, its effects on FcεRI (a high-affinity IgE receptor)-mediated mast cell activation, a pivotal process in inflammatory allergic reactions and innate immunity, have not been clearly demonstrated. In this study, we investigated the effects of PFOS on IgE/Ag (antigen)-stimulated mast cell activation and the underlying mechanisms using bone marrow-derived mast cells (BMMCs) and a passive cutaneous anaphylaxis (PCA) mouse model. Oral administration of PFOS attenuated IgE/Ag-stimulated PCA responses. In the BMMCs model, PFOS reduced IgE/Ag-stimulated degranulation, intracellular Ca2+ levels, eicosanoid synthesis, and mRNA expression of pro-inflammatory cytokines. Consistently, PFOS decreased the phosphorylation of Syk and Lck, central tyrosine kinases in IgE/Ag-stimulated mast cell activation, along with their downstream signaling molecules (PLCγ1, AKT, and MAPKs), through the activation of tyrosine phosphatase Src homology region 2 domain-containing phosphatase-1. Additionally, PFOS reduced the phosphorylation of FcεRI-associated tyrosine kinases Fyn and Lyn. Fluorine-19 nuclear magnetic resonance spectroscopy revealed reduced fluorine signals of PFOS upon interaction with the plasma membrane, suggesting that PFOS accumulates in plasma membranes and interferes with FcεRI signaling by acting upstream, close to the membrane. Moreover, PFOS attenuated lipopolysaccharide-stimulated mRNA expression of TNFα and IL-6. In conclusion, PFOS exposure disrupts FcεRI-mediated allergic responses and modulates innate immune responses.

Association between exposure to per- and polyfluoroalkyl substances (PFAS) and chronic cough in American adults: Results from NHANES 2003-2012

Chronic cough, which affects approximately 10 % of the global population, is recognized as a significant health issue, especially among females. Recent research suggests that chronic cough may be an independent disease rather than merely a symptom of other conditions. This study focuses on the potential role of exposure to perfluoroalkyl and polyfluoroalkyl substances (PFAS) in the development of chronic cough, noting that PFAS exposure has been linked to various adverse health outcomes. We aimed to explore the association between PFAS exposure and the risk of chronic cough in the U.S. population, analyzing data from the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2012 and examining potential sex-based differences. Our findings reveal several factors independently associated with an increased incidence of chronic cough, including elevated levels of serum perfluorobutane sulfonic acid (PFBS) and perfluoroheptanoic acid (PFHP). The multi-pollutant models consistently demonstrated a significant positive correlation between PFAS exposure and a higher risk of chronic cough in adult males, with PFBS and PFHP as the primary contributors. However, due to the cross-sectional design of the NHANES study, further research is necessary to elucidate the precise mechanisms by which PFAS contribute to chronic cough.

Arginine Metabolism Reprogramming in Perfluorooctanoic Acid (PFOA)-Induced Liver Injury

Perfluorooctanoic acid (PFOA) is a persistent pollutant that has gained worldwide attention, owing to its widespread presence in the environment. Previous studies have reported that PFOA upregulates lipid metabolism and is associated with liver injury in humans. However, when the fatty acid degradation pathway is activated, lipid accumulation still occurs, suggesting the presence of unknown pathways and mechanisms that remain to be elucidated. In this study, adult C57BL/6N mice were exposed to PFOA at 0.1, 1, and 10 mg/kg/day. Using integrated metabolomics and transcriptomics, it was uncovered that arginine metabolism was differentially downregulated in all three groups. In vitro studies confirmed the downregulation of arginine metabolism in MIHA cell lines treated with PFOA. Supplementation of arginine could effectively rescue liver injury and downregulate the chemokine levels caused by PFOA. This finding highlights the contribution of arginine metabolism in maintaining liver health following PFOA exposure and suggests potential mechanisms of metabolic and immune modulation.

Association of environmental pollutants with asthma and allergy, and the mediating role of oxidative stress and immune markers in adolescents

BACKGROUND

Asthma and allergic diseases are among the common causes of morbidity and mortality globally. Various environmental pollutants are linked to the development of asthma and allergic diseases. Evidence on the role of oxidative stress and immune markers in the association of environmental pollutants with asthma and allergy is scant. We examined cross-sectional associations between environmental pollutants and asthma and allergy, investigated mixture effects and possible mediation by oxidative stress or immune markers.

METHODS

We used data from the Flemish Environment and Health Study 2016-2020 (FLEHS IV), including 409 adolescents aged 13-16 years. Fifty-four pollutants, including metals, phthalates, Di(isononyl) cyclohexane-1,2-dicarboxylate (DINCH), bisphenols, currently used and legacy pesticides, flame retardants, per- and polyfluoroalkyl substances (PFAS), polyaromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) were analyzed. Outcomes were self-reported asthma, rhinitis, eczema, allergies, respiratory infection, and airway inflammation, measured through fractional exhaled nitric oxide (FeNO). Single pollutant models using multiple regression analysis and multipollutant models using Bayesian Kernel Machine Regression (BKMR) were fitted. As sensitivity analysis, Bayesian model averaging (BMA) and elastic net (ENET) models were also performed. For Bayesian models, posterior inclusion probabilities (PIP) were used to identify the most important chemicals. Mediation analysis was performed to investigate the role of oxidative stress, measured by urinary 8-hydroxy-2' -deoxyguanosine (8-OHdG), and immune markers (eosinophils, basophils, InterLeukin 8, InterLeukin 6, and Interferon-ᵧ in blood).

RESULTS

In single pollutant models, FeNO was significantly higher by 20% (95% CI: 6, 36%) and 13% (95% CI: 2, 25%) per interquartile range (IQR) fold in mono-n-butyl phthalate (MnBP) and mono-benzyl phthalate (MBzP), respectively. In BKMR analysis, the group PIPs indicated phthalates and DINCH as the most important group (group PIP = 0.509), with MnBP being the most important pollutant within that group (conditional PIP = 0.564; %change = 28%; 95%CI: 6, 54%). Similar patterns were observed in all multipollutant models. Eosinophil count mediated 37.8% (p = 0.018) and 27.9% (p = 0.045) of the association between MBzP and FeNO, and the association between MnBP and FeNO, respectively. 8-OHdG plays a significant mediating role in the association of 2,4-Dichlorophenoxyacetic acid (2,4-D) (55.4%), 3,5,6-Trichloro-2-pyridinol (TCPY) (48.1%), and 1-Naphthylamine (1-NAP) (32.7%) with rhinitis, while the total effects of these chemicals on rhinitis were not statistically significant.

CONCLUSIONS

This study found associations between phthalates, MnBP and MBzP, and elevated FeNO, which appeared to be mediated by eosinophil count. 8-OHdG plays a significant mediating role in the association between 2,4-D, TCPY, and 1-NAP with rhinitis, while their direct effects remain non-significant. Use of inflammatory and oxidative stress markers can enhance the understanding of inflammatory processes in asthma and allergic diseases due to environmental pollutants.

Unveiling the Research Void: Exploring the Reproductive Effects of PFAS Compounds on Male Health

Per- and polyfluoroalkyl substances (PFAS) represent an emerging concern for male reproductive health. Epidemiological studies have reported associations between increased PFAS exposure and reduced semen quality parameters, lower sperm counts, and potential alterations in reproductive hormone levels. Toxicology research has revealed possible mechanisms including blood-testis barrier disruption, oxidative stress, interference with testicular cell function, and epigenetic changes. However, significant uncertainties remain regarding definitive exposure-response relationships, developmental windows of heightened vulnerability, combined mixture effects, and causality interpretation, given limitations inherent to observational studies. Ongoing investigation of short-chain and replacement PFAS compounds is also critically needed. Additionally, directly connecting the mechanistic insights from animal models to human fertility impacts remains challenging. While controlled toxicology studies have described pathways by which PFAS could impair cellular functioning in the testes, uncertainty persists in extrapolating these experimental effects to real-world human exposures and sperm parameter declines reported epidemiologically. Overall, current findings suggest PFAS may contribute to declining male reproductive function, but additional clarification through well-designed longitudinal cohort studies integrated with mechanistic animal work is still warranted to confirm exposure-fertility links across a range of PFAS types and inform evidence-based public health mitigation strategies.

Asthma and decreased lung function in children exposed to perfluoroalkyl and polyfluoroalkyl substances (PFAS): An updated meta-analysis unveiling research gaps

BACKGROUND AND OBJECTIVE

Associations between exposure to per- and polyfluoroalkyl substances (PFAS) and pediatric asthma and reduced lung function in children are mixed and inconclusive. The study objective was to examine the extant research on exposure to PFAS and the diagnosis of asthma or decreased lung function in children <17 years of age to highlight what is known and to identify research gaps for future investigations.

METHODS

The present review was registered on the PROSPER database (CRD42023407172). We systematically searched several bibliographic databases (Scopus, Embase, Web of Science (core Collection), Medline, and CINAHL) along with grey literature sources in January 2023 to find relevant studies before this date. The National Toxicology Program's Office of Health Assessment and Translation (NTP OHAT) tool was applied to assess the risk of bias (RoB) assessment. We used a random-effects meta-analysis to assess the associations. From 12 observational epidemiological studies (out of 513) explored for qualitative analyses, 4 studies were included in quantitative analyses.

RESULTS

The meta-analysis revealed a significant association between exposures to perfluorooctanoate (PFOA) with the prevalence of children's asthma [Odds Ratios (OR) = 1.162 (95% CI: 1.004-1.321)] whereas the association for perfluorooctane sulfonate (PFOS) was not statistically significant [OR = 1.03 (95%CI: 0.806-1.265]. The narrative synthesis results of the four included studies that examined the effects of PFAS exposure on lung function did not demonstrate significant associations between exposure to PFAS and decreased lung function. The RoB for most included studies was assessed as probably low without serious limitations. However, two studies were at high risk of biases.

CONCLUSION

Our findings suggest that children who are exposed to PFOA are at a higher risk of developing asthma as well as the association between exposure to PFOS with impaired lung function. Large longitudinal studies with homogeneous PFAS exposures and standardized outcome measures are needed to ascertain these outcomes with improved certainty as well as toxicological studies to investigate the underlying mechanisms.

Advancing PFAS risk assessment: Integrative approaches using agent-based modelling and physiologically-based kinetic for environmental and health safety

Per- and polyfluoroalkyl substances (PFAS), ubiquitous in a myriad of consumer and industrial products, and depending on the doses of exposure represent a hazard to both environmental and public health, owing to their persistent, mobile, and bio accumulative properties. These substances exhibit long half-lives in humans and can induce potential immunotoxic effects at low exposure levels, sparking growing concerns. While the European Food Safety Authority (EFSA) has assessed the risk to human health related to the presence of PFAS in food, in which a reduced antibody response to vaccination in infants was considered as the most critical human health effect, a comprehensive grasp of the molecular mechanisms spearheading PFAS-induced immunotoxicity is yet to be attained. Leveraging modern computational tools, including the Agent-Based Model (ABM) Universal Immune System Simulator (UISS) and Physiologically Based Kinetic (PBK) models, a deeper insight into the complex mechanisms of PFAS was sought. The adapted UISS serves as a vital tool in chemical risk assessments, simulating the host immune system's reactions to diverse stimuli and monitoring biological entities within specific adverse health contexts. In tandem, PBK models unravelling PFAS' biokinetics within the body i.e. absorption, distribution, metabolism, and elimination, facilitating the development of time-concentration profiles from birth to 75 years at varied dosage levels, thereby enhancing UISS-TOX's predictive abilities. The integrated use of these computational frameworks shows promises in leveraging new scientific evidence to support risk assessments of PFAS. This innovative approach not only allowed to bridge existing data gaps but also unveiled complex mechanisms and the identification of unanticipated dynamics, potentially guiding more informed risk assessments, regulatory decisions, and associated risk mitigations measures for the future.

Exploring the link between the pediatric exposome, respiratory health, and executive function in children: a narrative review

Asthma is a highly prevalent inflammatory condition, significantly affecting nearly six million U.S. children and impacting various facets of their developmental trajectories including neurodevelopment. Evidence supports a link between pediatric environmental exposures in two key areas: asthma and executive function (E.F.). E.F.s are a collective of higher-order cognitive processes facilitating goal-oriented behaviors. Studies also identify asthma-associated E.F. impairments in children. However, limited research has evaluated the inter-relationships among environmental exposures, asthma, and E.F. in children. This review explored relevant research to identify and connect the potential mechanisms and pathways underlying these dynamic associations. The review suggests that the role of the pediatric exposome may function through (1) several underlying biological pathways (i.e., the lung-brain axis, neuroendocrine system, and hypoxia), which could drive asthma and maladaptive E.F. in children and (2) the relationships between the exposome, asthma, and E.F. is a bidirectional linkage. The review reveals essential synergistic links between asthma and E.F. deficits, highlighting the potential role of the pediatric exposome.

Per and poly-fluoroalkyl substances and respiratory health in an Inuit community

BACKGROUND

Concentrations of plasma per and poly-fluoroalkyl substances (PFAS) are elevated in the Inuit population of Nunavik and may be causing adverse health effects. Respiratory health outcomes have been associated with PFAS, but have not been explored in Inuit communities. The aim of the study was to examine the association between PFAS and respiratory health outcomes, and the moderating role of nutritional biomarkers.

METHODS

We included up to 1298 participants of the Qanuilirpitaa? 2017 survey aged 16-80 years. Generalized regression models were used to estimate the associations between six individual PFAS congeners and four self-reported symptoms, four spirometry measures, and physician-diagnosed asthma. Outcomes associated with PFAS from single chemical models were further explored using Bayesian Kernel Machine Regression (BKMR). The modifying effect of n-3 PUFA in red blood cell quartiles and vitamin D deficiency were examined on the associations between PFAS and respiratory outcomes.

RESULTS

PFNA and PFOS were associated with asthma (odds ratio (OR) 1.61, 95% confidence interval (CI) 1.12, 2.32; OR 1.45 95% CI 1.04, 2.03). PFOA, PFNA, PFDA and PFHxS were associated with a decrease in the ratio between the forced expiratory volume in the first second and forced vital capacity (FEV1/FVC). No associations were observed with self-reported respiratory symptoms. No associations were observed between a PFAS mixture and asthma. Some associations were modified by nutritional factors, namely, stronger associations between PFOA and PFHxS and asthma with lower n-3 PUFA levels and stronger associations between PFDA, PFUnDA and PFOS and FEV1/FVC with vitamin D deficiency.

CONCLUSION

These findings add to the growing literature on the impacts of PFAS on respiratory health, and the importance of their global regulation. Associations were modified by nutritional factors pointing to the nutritional value of traditional Inuit foods.

Developmental perfluorooctane sulfonic acid exposure exacerbates house dust mite induced allergic responses in adult mice

Perfluorooctane sulfonic acid (PFOS) is a long-chain per- and polyfluoroalkyl substance (PFAS), a persistent organic pollutant, which has been used in aqueous film-forming foams. Emerging epidemiological evidence indicates a significant body burden of PFOS is observed in the lungs. Furthermore, developmental PFOS exposure dysregulates lung development and exacerbates eosinophilic inflammation, which are critical risk factors for asthma. However, it is unknown whether PFOS exerts sex-dependent effects on house dust mite (HDM) induced asthmatic progression and allergic inflammation. In this study, timed pregnant Balb/cJ dams were dosed orally via PFOS (1.0 mg/kg/d) spiked or vehicle control mealworms from gestational day (GD) 0.5 to postnatal day (PND) 21. Subsequently, HDM (30 μg/day) was administered starting at PND 77-82 for 10 days, and the mice were sacrificed 48 h after their final treatment. The serum and lung PFOS concentrations were 3.391 ± 0.189 μg/mL and 3.567 ± 0.1676 μg/g in the offspring, respectively. Male mice exposed to PFOS + HDM showed higher total cell counts in bronchoalveolar lavage fluid (BALF), macrophage counts, and eosinophil counts compared to mice exposed to HDM alone. Female mice exposed to PFOS + HDM had increased BALF eosinophil percentage, mucous production, alternatively activated (M2) macrophage polarization, and M2-associated gene expression compared to female mice exposed to HDM alone. PFOS exposure had no significant effect on HDM-induced IL-4, IL-5, or IL-13, but RANTES was further elevated in female mice. Overall, our data suggest that developmental PFOS exposure increased the risk of exacerbated eosinophilic inflammation and M2 polarization, which were more severe in female mice, suggesting sex-dependent developmental effects of PFOS on allergic airway responses.

Developmental PFOS exposure alters lung inflammation and barrier integrity in juvenile mice

Emerging epidemiological evidence indicates perfluorooctane sulfonic acid (PFOS) is increasingly associated with asthma and respiratory viral infections. Animal studies suggest PFOS disrupts lung development and immuno-inflammatory responses, but little is known about the potential consequences on respiratory health and disease risk. Importantly, PFOS exposure during the critical stages of lung development may increase disease risk later in life. Thus, we hypothesized that developmental PFOS exposure will affect lung inflammation and alveolar/airway development in a sex-dependent manner. To address this knowledge gap, timed pregnant Balb/cJ dams were orally dosed with a PFOS (1.0 or 2.0 mg/kg/d) injected mealworm or a vehicle control daily from gestational day (GD) 0.5 to postnatal day (PND) 21, and offspring were sacrificed at PND 22-23. PFOS-exposed male offspring displayed increased alveolar septa thickness. Occludin was also downregulated in the lungs after PFOS exposure in mice, indicative of barrier dysfunction. BALF macrophages were significantly elevated at 2.0 mg/kg/d PFOS in both sexes compared with vehicles, whereas BALF cytokines (TNF-α, IL-6, KC, MIP-1α, MIP-1β, and MCP-1) were suppressed in PFOS-exposed male offspring compared with vehicle controls. Multiplex nucleic acid hybridization assay showed male-specific downregulation of cytokine gene expression in PFOS-exposed mice compared with vehicle mice. Overall, these results demonstrate PFOS exposure exhibits male-specific adverse effects on lung development and inflammation in juvenile offspring, possibly predisposing them to later-in-life respiratory disease. Further research is required to elucidate the mechanisms underlying the sex-differentiated pulmonary toxicity of PFOS.

Moderate-intensity physical activity reduces the role of serum PFAS on COPD: A cross-sectional analysis with NHANES data

BACKGROUND

Chronic obstructive pulmonary disease (COPD) has emerged as a leading cause of chronic disease morbidity and mortality globally, posing a substantial public health challenge. Perfluoroalkyl substances (PFAS) are synthetic chemicals known for their high stability and durability. Research has examined their potential link to decreased lung function. Physical activity (PA) has been identified as one of the primary modalities of the non-pharmacological treatment of COPD.

METHODS

To investigate the relationship between PFAS and COPD, and whether physical activity could reduce the risk of COPD caused by PFAS exposure, we used data from the NHANES 2013-2018, a cross-sectional study. Logistic regression analysis was used to examine the associations between PFAS and COPD in adult populations, and their associations in different PA types.

RESULTS

We finally included 4857 participants in the analysis, and found that Sm-PFOS (OR: 1.250), PFOA (OR: 1.398) and n-PFOA (OR: 1.354) were closely related to COPD; After stratified by gender, age and smoking, the results showed that Sm-PFOA (OR: 1.312) was related to COPD in female adult, and PFOA (OR: 1.398) and n-PFOA (OR: 1.354) were associated with COPD in male adults; The associations of Sm-PFOS (OR: 1.280), PFOA (OR: 1.481) and n-PFOA (OR: 1.424)with COPD tended to be stronger and more consistent in over 50 years old adults; Sm-PFOS was related to COPD in current smoker (OR: 1.408), and PFOA was related to COPD in former smoker (OR: 1.487); Besides, in moderate-intensity PA group, there were no associations of Sm-PFOS, PFOA and n-PFOA with COPD stratified by gender, age and smoking.

CONCLUSION

PFAS exposure may increase the risk of developing COPD, but regular moderate-intensity physical activity can protect individuals from evolving to the disease. However, longitudinal studies are needed to support these preliminary findings.

Gene expression patterns associated with PFOA exposure in Czech young men and women

Perfluorooctanoic acid (PFOA), a member of per- and polyfluoroalkyl substances (PFASs), has been widely used in manufacturing for decades. Currently, PFOA is strictly regulated, but due to its high stability and persistence, it is detected in both environmental as well as in human matrices. To elucidate mechanisms of PFOA toxicity in humans, we determined the genome-wide transcriptomic changes of peripheral blood mononuclear cells (PBMC) responding to PFOA exposure in a sex-stratified analysis. This work employed samples from 145 female and 143 male participants of the CELSPAC: YA study to characterize PFOA-associated transcripts in a broader context using computational analysis. PFOA-associated gene expression differed significantly between men and women, as only 2 % of mapped genes were expressed in both sexes. Disease-specific enrichment analysis revealed cancer and immune-related disease terms as those most enriched in male and female populations. Patterns of enriched terms within the gene set enrichment analysis indicated three main targets of PFOA toxicity: i) lipid metabolism for women; ii) cell cycle regulation for men; and iii) immune system response for both sexes. In summary, our genome-wide transcriptomics analysis described sex-specific differences in PFOA-associated gene expression and provided evidence about biological pathways underlying PFOA toxicity in humans.

Per- and poly-fluoroalkyl substances (PFAS) effects on lung health: a perspective on the current literature and future recommendations

Per- and poly-fluoroalkyl substances (PFAS) are a broad class of synthetic compounds widely used in commercial applications. The persistent nature of PFAS in the environment has earned them the epithet "forever chemicals." Concerns arise from widespread exposure to PFAS from occupational, household, and environmental sources. This widespread use of PFAS is particularly concerning, as emerging epidemiological evidence highlights their adverse effects on lung health. Such adverse impacts include impaired fetal lung development, reduced immune function in children, and potential links to lung cancer. Both in vivo and in vitro studies illuminate potential mechanisms underlying such adverse health outcomes subsequent to PFAS inhalation exposure, which may include immunomodulation, oxidative stress, and disruptions to epithelial barriers. However, evidence-based information focusing on the mechanisms of PFAS-mediated lung injury is lacking. Additionally, the discrepancies between data collected from animal and epidemiological studies highlight the need for improved approaches to better understand the toxicity results of PFAS exposure. To address these gaps, we recommend leveraging route-to-route extrapolation for risk assessment, prioritizing research on understudied PFAS, and adopting physiologically relevant, high-throughput approaches. These strategies are aimed at enhancing our understanding of PFAS inhalation effects, aiding in more informed risk management decisions. In this review, we summarize the current literature on PFAS exposure, emphasizing its adverse effects on lung health, particularly through inhalation. We then discuss the current knowledge on mechanisms underlying tissue- and cellular-level adverse outcomes caused by PFAS.

Associations of per- and polyfluoroalkyl substances (PFAS) and their mixture with risk of rheumatoid arthritis in the U.S. adult population

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are known environmental contaminants with immunosuppressive properties. Their connection to rheumatoid arthritis (RA), a condition influenced by the immune system, is not well studied. This research explores the association between PFAS exposure and RA prevalence.

METHODS

This research utilized data from the NHANES, encompassing a sample of 10,496 adults from the 2003-2018 cycles, focusing on serum levels of several PFAS. The presence of RA was determined based on self-reports. This study used multivariable logistic regression to assess the relationship between individual PFAS and RA risk, adjusting for covariates to calculate odds ratios (ORs). The combined effects of PFAS mixtures were evaluated using BKMR, WQS regression, and quantile g-computation. Additionally, sex-specific associations were explored through stratified analysis.

RESULTS

Higher serum PFOA (OR = 0.88, 95% CI: 0.79, 0.98), PFHxS (OR = 0.91, 95% CI: 0.83, 1.00), PFNA (OR = 0.87, 95% CI: 0.77, 0.98), and PFDA (OR = 0.89, 95% CI: 0.81, 0.99) concentration was related to lower odds of RA. Sex-specific analysis in single chemical models indicated the significant inverse associations were only evident in females. BKMR did not show an obvious pattern of RA estimates across PFAS mixture. The outcomes of sex-stratified quantile g-computation demonstrated that an increase in PFAS mixture was associated with a decreased odds of RA in females (OR: 0.76, 95% CI: 0.62, 0.92). We identified a significant interaction term of the WQS*sex in the 100 repeated hold out WQS analysis. Notably, a higher concentration of the PFAS mixture was significantly associated with reduced odds of RA in females (mean OR = 0.93, 95% CI: 0.88, 0.98).

CONCLUSIONS

This study indicates potential sex-specific associations of exposure to various individual PFAS and their mixtures with RA. Notably, the observed inverse relationships were statistically significant in females but not in males. These findings contribute to the growing body of evidence indicating that PFAS may have immunosuppressive effects.

Systemic and immunotoxicity induced by topical application of perfluorohexane sulfonic acid (PFHxS) in a murine model

Per- and polyfluoroalkyl substances (PFAS) are a large group of stable synthetic surfactants that are incorporated into numerous products for their water and oil resistance and have been associated with adverse health effects. The present study evaluated the systemic and immunotoxicity of sub-chronic 28- or 10-day dermal exposure of PFHxS (0.625-5% or 15.63-125 mg/kg/dose) in a murine model. Elevated levels of PFHxS were detected in the serum and urine, suggesting that absorption is occurring through the dermal route. Liver weight (% body) significantly increased and spleen weight (% body) significantly decreased with PFHxS exposure, which was supported by histopathological changes. Additionally, PFHxS significantly reduced the humoral immune response and altered immune subsets in the spleen, suggesting immunosuppression. Gene expression changes were observed in the liver, skin, and spleen with genes involved in fatty acid metabolism, necrosis, and inflammation. Immune-cell phenotyping identified significant decreases in B-cells, NK cells, and CD11b+ monocyte/macrophages in the spleen along with increases in CD4+ and CD8+ T-cells, NK cells, and neutrophils in the skin. These findings support dermal PFHxS-induced liver damage and immune suppression. Overall, data support PFHxS absorption through the skin and demonstrate immunotoxicity via this exposure route, suggesting the need for further examination.

Environmental exposure to per- and polyfluoroalkyl substances mixture and asthma in adolescents

BACKGROUND

Previous epidemiological studies about the relationship between per- and polyfluoroalkyl substances (PFAS) concentrations and adolescent asthma have typically examined single PFAS, without considering the mixtures effects of PFAS.

METHODS

Using data from the 2013-2018 National Health and Nutrition Examination Survey (NHANES), 886 adolescents aged 12-19 years were included in this study. We explored the association between PFAS mixture concentrations and adolescent asthma using weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) models, respectively.

RESULTS

After adjusting for confounders, the results of the WQS regression and BKMR models were consistent, with mixed exposure to the five PFAS not significantly associated with asthma in all adolescents. The association remained nonsignificant in the subgroup analysis by sex.

CONCLUSIONS

Our study demonstrated no significant association between mixed exposure to PFAS and adolescent asthma, and more large cohort studies are needed to confirm this in the future.

Quantifying Disparities in Per- and Polyfluoroalkyl Substances (PFAS) Levels in Drinking Water from Overburdened Communities in New Jersey, 2019-2021

BACKGROUND

Policymakers have become increasingly concerned regarding the widespread exposure and toxicity of per- and polyfluoroalkyl substances (PFAS). While concerns exist about unequal distribution of PFAS contamination in drinking water, research is lacking.

OBJECTIVES

We assess the scope of PFAS contamination in drinking water in New Jersey (NJ), the first US state to develop regulatory levels for PFAS in drinking water. We test for inequities in PFAS concentrations by community sociodemographic characteristics.

METHODS

We use PFAS testing data for community water systems (CWS) (n = 491 ) from the NJ Department of Environmental Protection (NJDEP) from 2019 to 2021 and demographic data at the block group level from the US Census to estimate the demographics of the NJ population served by CWS. We use difference in means tests to determine whether CWSs serving "overburdened communities" (OBCs) have a statistically significant difference in likelihood of PFAS detections. OBCs are defined by the NJDEP to be census block groups in which: a) at least 35% of the households qualify as low-income, b) at least 40% of the residents identify as people of color, or c) at least 40% of the households have limited English proficiency. We calculate statewide summary statistics to approximate the relative proportions of sociodemographic groups that are served by CWSs with PFAS detections.

RESULTS

We find that 63% of all CWSs tested by NJDEP from 2019 to 2021 had PFAS detections in public drinking water, collectively serving 84% of NJ's population receiving water from CWSs. Additionally, CWSs serving OBCs had a statistically significant higher likelihood of PFAS detection and a higher likelihood of exposure above state MCLs. We also find that a larger proportion of people of color lived in CWS service areas with PFAS detections compared to the non-Hispanic white population.

DISCUSSION

These findings quantitatively identify disparities in PFAS contamination of drinking water by CWS service area and highlight the extent of PFAS drinking water contamination and the importance of PFAS remediation efforts for protecting environmental health and justice. https://doi.org/10.1289/EHP12787.

Early menarche and other endocrine disrupting effects of per- and polyfluoroalkyl substances (PFAS) in adolescents from Northern Norway. The Fit Futures study

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) comprise a large group of chemicals that are ubiquitous in the environment and include recognized persistent organic pollutants. The aim of this cross-sectional study was to investigate possible endocrine disrupting effects of different PFAS in adolescents.

METHODS

Serum concentrations of PFAS, thyroid, parathyroid and steroid hormones were measured in 921 adolescents aged 15-19 years in the Fit Futures study, Northern Norway. The questionnaire included data on self-reported age at menarche and puberty development score (PDS). Multiple linear and logistic regression analyses and principle component analyses (PCA) were used to assess associations of PFAS with hormones concentrations and puberty indices.

RESULTS

In girls, total PFAS (∑PFAS), perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoate (PFNA), perfluorodecanoate (PFDA) were positively associated with dehydroepiandrosterone sulfate (DHEAS) and negatively associated with 11-deoxycorticosterone (11-DOC)/DHEAS ratio. In boys, the associations with 11-DOC/DHEAS ratio were positive for ∑PFAS, perfluoroheptanoate (PFHpA), perfluoroheptane sulfonate (PFHpS), PFOA, and PFOS. Perfluoroundecanoate (PFUnDA) was negatively associated with free thyroxine (fT4) and free triiodothyronine (fT3) in boys. PFNA and PFDA were also negatively associated with fT3 in boys. Serum parathyroid hormone concentration (PTH) was negatively associated with ∑PFAS and perfluorohexane sulfonate (PFHxS) in girls, and with PFOS in boys. PFDA and PFUnDA were positively associated with early menarche, while ∑PFAS and PFOA were positively associated with PDS in boys. No associations of PFAS with serum testosterone, follicle-stimulating hormone, or luteinizing hormone were found in either sex. In girls, PFOA was positively associated with free testosterone index (FTI). In boys, PFOA was positively associated with androstendione and 17-OH-progesterone, while PFHpA was positively associated with estradiol.

CONCLUSIONS

Serum concentrations of several PFAS were associated with parathyroid and steroid hormones in both sexes, and with thyroid hormones in boys, as well as with early menarche in girls and higher PDS in boys.

The association between prenatal per-and polyfluoroalkyl substance levels and Kawasaki disease among children of up to 4 years of age: A prospective birth cohort of the Japan Environment and Children's study

Kawasaki disease (KD) is common among pediatric patients and is associated with an increased risk of later cardiovascular complications, though the precise pathophysiology of KD remains unknown. Per- and polyfluoroalkyl substances (PFAS) have gathered notoriety as the causal pathogens of numerous diseases as well as for their immunosuppressive effects. The present epidemiological study aims to assess whether PFAS may affect KD risk. We evaluated research participants included in the ongoing prospective nationwide birth cohort of the Japan Environment and Children's Study (JECS). Among the over 100,000 pregnant women enrolled in the JECS study, 28 types of PFAS were measured in pregnancy in a subset of participants (N = 25,040). The JECS followed their children born between 2011 and 2014 (n total infants = 25,256; n Kawasaki disease infants = 271), up to age four. Among the 28 types of PFAS, those which were detected in >60 % of participants at levels above the method reporting limit (MRL) were eligible for analyses. Multivariable logistic regressions were implemented on the seven eligible PFAS, adjusting for multiple comparison effects. Finally, we conducted Weighted Quantile Sum (WQS) and Bayesian kernel machine regression (BKMR) to assess the effects of the PFAS mixture on KD. Therefore, we ran the BKMR model using kernel mechanical regression equations to examine PFAS exposure and the outcomes of KD. Upon analysis, the adjusted multivariable regression results did not reach statistical significance for the seven eligible substances on KD, while odds ratios were all under 1.0. WQS regression was used to estimate the mixture effect of the seven eligible PFAS, revealing a negative correlation with KD incidence; similarly, BKMR implied an inverse association between the PFAS mixture effect and KD incidence. In conclusion, PFAS exposure was not associated with increased KD incidence.

Prenatal exposure to poly- and perfluoroalkyl substances and the incidence of asthma in early childhood

EXPOSURE TO POLY: and perfluoroalkyl substances (PFAS) in early life may increase the risk of childhood asthma, but evidence has been inconsistent. We estimated associations between maternal serum concentrations of PFAS during pregnancy and clinician-diagnosed asthma incidence in offspring through age eight. We included 597 mother-child pairs with PFAS quantified in mid-pregnancy serum and childhood medical records reviewed for asthma diagnoses. We used separate Cox proportional hazards models to assess the relationship between log-transformed concentrations of five PFAS and the incidence of asthma. We estimated associations between the PFAS mixture and clinician-diagnosed asthma incidence using quantile-based g-computation. PFAS concentrations were similar to those among females in the US general population. Seventeen percent of children (N = 104) were diagnosed with asthma during follow-up. Median (interquartile range) duration of follow-up was 4.7 (4.0, 6.2) years, and median age at asthma diagnosis was 1.7 (0.9, 2.8) years. All adjusted hazard ratios (HRs) were elevated, but all 95% confidence intervals (CI) included the null. The HR (95% CI) of asthma for a one-quartile increase in the PFAS mixture was 1.17 (0.86, 1.61). In this cohort of children followed to eight years of age, prenatal PFAS concentrations were not significantly associated with incidence of clinician-diagnosed asthma.

Legacy and emerging per- and polyfluoroalkyl substances suppress the neutrophil respiratory burst

Per- and polyfluoroalkyl substances (PFASs) are used in a multitude of processes and products, including nonstick coatings, food wrappers, and fire-fighting foams. These chemicals are environmentally-persistent, ubiquitous, and can be detected in the serum of 98% of Americans. Despite evidence that PFASs alter adaptive immunity, few studies have investigated their effects on innate immunity. The report here presents results of studies that investigated the impact of nine environmentally-relevant PFASs [e.g. perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid potassium salt (PFOS-K), perfluorononanoic acid (PFNA), perfluorohexanoic acid (PFHxA), perfluorohexane sulfonic acid (PFHxS), perfluorobutane sulfonic acid (PFBS), ammonium perfluoro(2-methyl-3-oxahexanoate) (GenX), 7H-perfluoro-4-methyl-3,6-dioxa-octane sulfonic acid (Nafion byproduct 2), and perfluoromethoxyacetic acid sodium salt (PFMOAA-Na)] on one component of the innate immune response, the neutrophil respiratory burst. The respiratory burst is a key innate immune process by which microbicidal reactive oxygen species (ROS) are rapidly induced by neutrophils in response to pathogens; defects in the respiratory burst can increase susceptibility to infection. The study here utilized larval zebrafish, a human neutrophil-like cell line, and primary human neutrophils to ascertain whether PFAS exposure inhibits ROS production in the respiratory burst. It was observed that exposure to PFHxA and GenX suppresses the respiratory burst in zebrafish larvae and a human neutrophil-like cell line. GenX also suppressed the respiratory burst in primary human neutrophils. This report is the first to demonstrate that these PFASs suppress neutrophil function and support the utility of employing zebrafish larvae and a human cell line as screening tools to identify chemicals that may suppress human immune function.

Advanced electrocatalytic redox processes for environmental remediation of halogenated organic water pollutants

Halogenated organic compounds are widespread, and decades of heavy use have resulted in global bioaccumulation and contamination of the environment, including water sources. Here, we introduce the most common halogenated organic water pollutants, their classification by type of halogen (fluorine, chlorine, or bromine), important policies and regulations, main applications, and environmental and human health risks. Remediation techniques are outlined with particular emphasis on carbon-halogen bond strengths. Aqueous advanced redox processes are discussed, highlighting mechanistic details, including electrochemical oxidations and reductions of the water-oxygen system, and thermodynamic potentials, protonation states, and lifetimes of radicals and reactive oxygen species in aqueous electrolytes at different pH conditions. The state of the art of aqueous advanced redox processes for brominated, chlorinated, and fluorinated organic compounds is presented, along with reported mechanisms for aqueous destruction of select PFAS (per- and polyfluoroalkyl substances). Future research directions for aqueous electrocatalytic destruction of organohalogens are identified, emphasizing the crucial need for developing a quantitative mechanistic understanding of degradation pathways, the improvement of analytical detection methods for organohalogens and transient species during advanced redox processes, and the development of new catalysts and processes that are globally scalable.

Perfluoroalkyl Substances (PFAS) Affect Inflammation in Lung Cells and Tissues

Adverse lung outcomes from exposure to per-and polyfluoroalkyl substances (PFAS) are known; however, the mechanism of action is poorly understood. To explore this, human bronchial epithelial cells were grown and exposed to varied concentrations of short-chain (perfluorobutanoic acid, perflurobutane sulfonic acid and GenX) or long-chain (PFOA and perfluorooctane sulfonic acid (PFOS)) PFAS, alone or in a mixture to identify cytotoxic concentrations. Non-cytotoxic concentrations of PFAS from this experiment were selected to assess NLRP3 inflammasome activation and priming. We found that PFOA and PFOS alone or in a mixture primed and activated the inflammasome compared with vehicle control. Atomic force microscopy showed that PFOA but not PFOS significantly altered the membrane properties of cells. RNA sequencing was performed on the lungs of mice that had consumed PFOA in drinking water for 14 weeks. Wild type (WT), PPARα knock-out (KO) and humanized PPARα (KI) were exposed to PFOA. We found that multiple inflammation- and immune-related genes were affected. Taken together, our study demonstrated that PFAS exposure could alter lung biology in a significant manner and may contribute to asthma/airway hyper-responsiveness.

Associations between serum per- and polyfluoroalkyl substances and asthma morbidity in the National Health and Nutrition Examination Survey (2003-18)

Background

Per- and polyfluoroalkyl substances (PFAS) are a class of chemicals widely used in manufacturing and are highly resistant to degradation, so they accumulate in the environment. Serum concentrations of these so-called forever chemicals have been associated with impairment of innate and adaptive immune responses. The relationship between serum PFAS levels and asthma morbidity has not been studied.

Objective

We tested the association between serum PFAS concentration and asthma exacerbations.

Methods

We performed secondary analysis of data from the National Health and Nutrition Examination Survey (NHANES, 2003-18). We fit multivariable logistic regression models to estimate odds ratios and 95% CIs for asthma exacerbation in the prior 12 months, given serum concentrations of PFAS. Models were adjusted for relevant covariates.

Results

Of 1101 participants with self-reported current asthma and available serum PFAS data, we observed that higher serum perfluorooctanoic and perfluorodecanoic acids were associated with greater odds of asthma attacks in the previous 12 months (respectively, adjusted odds ratio 1.16, 95% CI 1.01, 1.33; and adjusted odds ratio 1.21, 95% CI 1.03, 1.43). After stratification by age, the association between perfluorooctanoic acid and asthma attacks was significant in the 12-18-year-old group only (adjusted odds ratio 1.56, 95% CI 1.06, 2.31). No significant relationships were observed between PFAS and asthma-related emergency department visits. After correction for multiple comparison testing, none of the associations reached the threshold of significance.

Conclusion

The role of these bioaccumulative forever chemicals in susceptibility to asthma attacks warrants further examination in longitudinal studies. (J Allergy Clin Immunol Global 2023;2:100078.).

Impact of PFAS exposure on prevalence of immune-mediated diseases in adults in the Czech Republic

BACKGROUND

Per- and polyfluoroalkyl substances (PFASs) are emerging environmental contaminants with multiple hazardous properties including immunomodulation potency. Human exposure to PFASs has been associated with various immune-mediated diseases and outcomes. This study aimed to investigate the association between PFAS exposure and immune-mediated diseases such as allergies, eczemas, and autoimmune diseases in a population of adults in the Czech Republic.

METHODS

This study included 309 adults from the Central European Longitudinal Study of Parents and Children: Young Adults (CELSPAC: YA). 12 PFASs were measured in participants' serum by HPLC-MS/MS, 3 PFASs were removed from the subsequent analyses due to low detection frequency. The associations of 9 PFASs with 9 immune-mediated diseases were assessed by logistic regression. Furthermore, Bayesian kernel machine regression (BKMR) was used to estimate the effect of the PFAS mixture on immune-mediated diseases. All analyses were adjusted for sex, age, BMI, smoking, education, and family history of immune-mediated diseases. In cases of a statistically significant interaction of PFASs and sex, stratified analyses were performed for men and women.

RESULTS

Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) were negatively associated with both atopic eczema (OR per IQR increase 0.58 (95% CI 0.37-0.90) for PFOA and 0.56 (0.32-0.95) for PFOS) and contact dermatitis (0.37 (0.16-0.85) for PFOA and 0.33 (0.11-0.94) for PFOS). Perfluoroundecanoate (PFUnDA) was negatively associated with pollen, dust, and mite allergy (0.62 (0.43-0.89)). BKMR modelling showed a negative tendency in the overall effect of PFAS mixture on immune-health outcomes. Based on the stratified analysis, sex was suggested to be an effect modifier in the association of PFOS and atopic eczema.

CONCLUSION

Our results contribute to the body of literature that observes the immunosuppressive effect of PFAS exposure during eczemas and allergies, both for PFASs individually and as a mixture.

Perfluoroalkyl substance exposure is associated with asthma and innate immune cell count in US adolescents stratified by sex

Exposure to perfluoroalkyl substances (PFAS) may be harmful to humans; however, previous studies have been inconsistent regarding the potential for PFAS-induced immunosuppresion. This study explored the relationship between PFAS exposure and risks of asthma, wheezing, and immunosuppression in 12-19 year-olds using the National Health and Nutrition Examination Survey (NHANES) data. Logistic regression models were used to reveal associations between serum PFAS levels and risks of asthma, wheezing, asthma attack, and emergency department visits. Pearson's correlation was used to determine the relationship between serum PFAS levels and leukocyte count. Data were also stratified by sex. We found that medium-low levels of serum perfluorooctane sulfonate (PFOS) (6.90-12.40 ng/mL) and serum perfluorooctanoic acid (PFOA) (2.43-3.60 ng/mL) were negatively related, respectively, to current asthma and wheezing in boys, and to wheezing in girls. Meanwhile, boys with medium-high levels (1.50-3.00 ng/mL) of serum perfluorohexanesulfonate (PFHxS) had a high risk of wheezing. Among asthmatic participants, both medium-high levels (3.75-5.07 ng/mL) of serum PFOA and high levels (> 3.92 ng/mL) of PFHxS correlated with asthma attacks in boys; likewise, medium-low levels (0.70-0.99 ng/mL) of serum PFNA correlated with asthma attacks in girls. Also, PFOA and PFNA levels were weakly positively correlated with basophil count, whereas PFOS levels were weakly negatively correlated with eosinophils in asthmatic boys, indicating that basophils may be important in the immune response to PFAS exposure among asthmatics.

Consideration of pathways for immunotoxicity of per- and polyfluoroalkyl substances (PFAS)

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are of public health concern, because of their ubiquitous and extremely persistent occurrence, and depending on their structure, their bio-accumulative, mobile and toxic properties. Human health effects associated with exposure to PFAS include adverse effects on the immune system. In 2020, EFSA (the European Food Safety Authority) defined adverse effects on the immune system as the most critical effect for human health risk assessment, based on reduced antibody responses to childhood vaccines and similar effects observed in experimental animal studies. Likewise, the U.S. EPA (Environmental Protection Agency) considers PFAS-induced immunotoxicity, especially in children, as the critical effect for risk assessment. However, the mechanisms by which antibody concentrations are impacted are not completely understood. Furthermore, other targets of the immune system functions have been reported in the literature.

OBJECTIVE

The aim of this review is to explore PFAS-associated immune-related effects. This includes, relevant mechanisms that may underlie the observed effects on the immune system, immunosuppression as well as immunoenhancement, such as i) modulation of cell signalling and nuclear receptors, such as NF-κB and PPARs; ii) alteration of calcium signalling and homoeostasis in immune cells; iii) modulation of immune cell populations; iv) oxidative stress and v) impact on fatty acid metabolism & secondary effects on the immune system.

METHODS

A literature research was conducted using three databases (Web of Science, PubMed, and Scopus), which were searched in July 2021 for relevant studies published in the time frame from 2018 to 2021. In total, 487 publications were identified as potentially eligible and following expert-based judgement, articles relevant for mechanisms of PFAS induced immunotoxicity are discussed.

CONCLUSIONS

Taken together, we show that there is substantial evidence from both in vitro and in vivo experimental as well as epidemiological studies, supporting that various PFAS, not only PFOA and PFOS, affect multiple aspects of the immune system. Timing of exposure is critical, because the developing immune system is especially vulnerable to toxic insults, resulting in a higher risk of particularly adverse immune effects but also other organs later in life.

PFAS levels and determinants of variability in exposure in European teenagers - Results from the HBM4EU aligned studies (2014-2021)

BACKGROUND

Perfluoroalkyl substances (PFAS) are man-made fluorinated chemicals, widely used in various types of consumer products, resulting in their omnipresence in human populations. The aim of this study was to describe current PFAS levels in European teenagers and to investigate the determinants of serum/plasma concentrations in this specific age group.

METHODS

PFAS concentrations were determined in serum or plasma samples from 1957 teenagers (12-18 years) from 9 European countries as part of the HBM4EU aligned studies (2014-2021). Questionnaire data were post-harmonized by each study and quality checked centrally. Only PFAS with an overall quantification frequency of at least 60% (PFOS, PFOA, PFHxS and PFNA) were included in the analyses. Sociodemographic and lifestyle factors were analysed together with food consumption frequencies to identify determinants of PFAS exposure. The variables study, sex and the highest educational level of household were included as fixed factors in the multivariable linear regression models for all PFAS and each dietary variable was added to the fixed model one by one and for each PFAS separately.

RESULTS

The European exposure values for PFAS were reported as geometric means with 95% confidence intervals (CI): PFOS [2.13 μg/L (1.63-2.78)], PFOA ([0.97 μg/L (0.75-1.26)]), PFNA [0.30 μg/L (0.19-0.45)] and PFHxS [0.41 μg/L (0.33-0.52)]. The estimated geometric mean exposure levels were significantly higher in the North and West versus the South and East of Europe. Boys had significantly higher concentrations of the four PFAS compared to girls and significantly higher PFASs concentrations were found in teenagers from households with a higher education level. Consumption of seafood and fish at least 2 times per week was significantly associated with 21% (95% CI: 12-31%) increase in PFOS concentrations and 20% (95% CI: 10-31%) increase in PFNA concentrations as compared to less frequent consumption of seafood and fish. The same trend was observed for PFOA and PFHxS but not statistically significant. Consumption of eggs at least 2 times per week was associated with 11% (95% CI: 2-22%) and 14% (95% CI: 2-27%) increase in PFOS and PFNA concentrations, respectively, as compared to less frequent consumption of eggs. Significantly higher PFOS concentrations were observed for participants consuming offal (14% (95% CI: 3-26%)), the same trend was observed for the other PFAS but not statistically significant. Local food consumption at least 2 times per week was associated with 40% (95% CI: 19-64%) increase in PFOS levels as compared to those consuming local food less frequently.

CONCLUSION

This work provides information about current levels of PFAS in European teenagers and potential dietary sources of exposure to PFAS in European teenagers. These results can be of use for targeted monitoring of PFAS in food.

Short-Term Exposure of Dactylis glomerata Pollen to Atmospheric Gaseous Pollutants Is Related to an Increase in IgE Binding in Patients with Grass Pollen Allergies

The concentrations of nitrogen dioxide (NO2) and tropospheric ozone (O3) in urban and industrial site atmospheres are considered key factors associated with pollen-related respiratory allergies. This work studies the effects of NO2 and O3 on the protein expression profile and IgE binding in patients with grass allergies to Dactylis glomerata pollen extracts. Pollens were collected during the flowering season and were exposed to NO2 and O3 in a controlled environmental chamber. The amount of soluble protein was examined using the Bradford method, and the protein expression profile and antigenic properties were analysed using the immunoblotting and enzyme-linked immunosorbent assay (ELISA), respectively. Our results showed apparent inter-sera differences concerning the number and intensity of IgE reactivity, with the most prominent at bands of 55 kDa, 35, 33, and 13 kDa. In the 13 kDa band, both gases tend to induce an increase in IgE binding, the band at 33 kDa showed a tendency towards a reduction, particularly pollen exposed to O3. Reactive bands at 55 and 35 kDa presented an increase in the IgE binding pattern for all the patient sera samples exposed to NO2, but the samples exposed to O3 showed an increase in some sera and in others a decrease. Regarding the ELISA results, out of the 21 tested samples, only 9 showed a statistically significant increase in total IgE reactivity after pollen exposure to the pollutants. Our study revealed that although airborne pollen allergens might be affected by air pollution, the possible impacts on allergy symptoms might vary depending on the type of pollutant and the patient's sensitisation profile.

Persistent organic pollutants in foods, their interplay with gut microbiota and resultant toxicity

Persistent Organic Pollutants (POPs) have become immensely prevalent in the environment as a result of their unique chemical properties (persistent, semi-volatile and bioaccumulative nature). Their occurrence in the soil, water and subsequently in food has become a matter of concern. With food being one of the major sources of exposure, the detrimental impact of these chemicals on the gut microbiome is inevitable. The gut microbiome is considered as an important integrant for human health. It participates in various physiological, biochemical and immunological activities; thus, affects the metabolism and physiology of the host. A myriad of studies have corroborated an association between POP-induced gut microbial dysbiosis and prevalence of disorders. For instance, ingestion of polychlorinated biphenyls, polybrominated diphenyl ethers or organochlorine pesticides influenced bile acid metabolism via alteration of bile salt hydrolase activity of Lactobacillus, Clostridium or Bacteroides genus. At the same time, some chemicals such as DDE have the potential to elevate Proteobacteria and Firmicutes/Bacteriodetes ratio influencing their metabolic activity leading to enhanced short-chain fatty acid synthesis, ensuing obesity or a pre-diabetic state. This review highlights the impact of POPs exposure on the gut microbiota composition and metabolic activity, along with an account of its corresponding consequences on the host physiology. The critical role of gut microbiota in impeding the POPs excretion out of the body resulting in their prolonged exposure and consequently, enhanced degree of toxicity is also emphasized.

Simultaneous determination of poly- and perfluoroalkyl substances and organophosphorus flame retardants in serum by ultra-performance liquid chromatography/tandem mass spectrometry

RATIONALE

Poly- and perfluoroalkyl substances (PFASs) and organophosphorus flame retardants (OPFRs) are two types of emerging organic pollutants with potential human health hazards. Here, a rapid and sensitive method was developed for the determination of sixteen PFASs and seven OPFRs in human serum by ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS).

METHODS

After optimizing the chromatographic and mass spectrometric conditions, respectively, 100 μL of serum sample was liquid-liquid extracted using 8 mL of methyl tert-butyl ether. The 23 targets were quantified within 8 min. All targets were quantified by the isotope-internal standard method in both negative- and positive-ion mode by UPLC/MS/MS.

RESULTS

The method was validated in terms of sensitivity, linearity, precision, and accuracy. The limit of detection ranged between 0.004 and 0.650 ng/mL. Recoveries ranged from70.0% to 118.9% with a relative standard deviation lower than 20%. The developed method was successfully applied to analyze targeted analytes in human serum samples. A total of 13 of 23 analytes were detected in over 50% of samples.

CONCLUSIONS

A sensitive and rapid method was developed to quantify sixteen PFASs and seven OPFRs in serum. Sensitivity, linearity, recovery, and precision were validated and found to be satisfactory. This method can be a valuable tool for evaluation of exposure to both PFASs and OPFRs with high separation efficiency and sensitivity.

Health at age 17 in Norwegian adolescents: Mental and physical status in the national cohort born in 2001

AIMS

We present self-reported data on physical and mental health at age 17 years from 82% of Norwegians born in 2001.

METHODS

In Norway, the Armed Forces require that each resident who reaches the age of 17 years completes a self-administered declaration of health that is used for military selection. The declaration collects information on height and weight, various clinically diagnosed diseases, mental and behavioural disorders, and other health conditions where clinical diagnosis is not required. In 2018, there were 65,913 adolescents born in 2001 living in Norway, of whom 10,223 were exempt from completing the declaration; declarations were therefore sent to 55,690 participants. We included 54,132 participants who completed the declaration (response rate 97.2%): 27,220 male and 26,912 female respondents.

RESULTS

We found that 18% of male and 28% of female respondents reported at least one clinically diagnosed disease, mental disorder or behavioural disorder. Among health condition where clinical diagnosis was not required, 19% of male and 37% of female respondents reported anxiety/depression affecting daily life and 10 versus 18% reported migraines/recurring headaches. The respondents probably represent the healthiest part of the total cohort of 17-year-old Norwegians because those who are exempt from completing the declaration are already considered unfit for military service.

CONCLUSIONS

These data represent a rich resource for further research. Similar data exist for the birth cohorts in 1993-2003. We encourage further research that can help decision-makers identify areas of concern that should be targeted for interventions.

Registered human trials addressing environmental and occupational toxicant exposures: Scoping review of immunological markers and protective strategies

Exposure to pollution is a worldwide societal challenge participating in the etiology and progression of different diseases. However, the scarce information hinders our understanding of the actual level of human exposure and its specific effects. Inadequate and excessive immune responses underlie diverse chronic diseases. Yet, it is unclear which and how toxicant exposures affect the immune system functions. There is a multiplicity of immunological outcomes and biomarkers being studied in human trials related to exposure to different toxicants but still without clear evidence of their value as biomarkers of exposure or effect. The main aim of this study was to collect scientific evidence and identify relevant immunological biomarkers used at the clinical level for toxicant exposures. We used the platform clinical trials.gov as a database tool. First, we performed a search combining research items related to toxicants and immunological parameters. The resulting117 clinical trials were examined for immune-related outcomes and specific biomarkers evaluated in subjects exposed to occupational and environmental toxicants. After categorization, relevant immunological outcomes and biomarkers were identified related to systemic and airway inflammation, modulation of immune cells, allergy and autoimmunity. In general, the immune markers related to inflammation are more frequently investigated for exposure to pollutants, namely IL-6, C-reactive protein (CRP) and nitric oxide (NO). Nevertheless, the data also indicated that prospective biomarkers of effect are gaining ground and a guiding representation of the established and novel biomarkers is suggested for upcoming trials. Finally, potential protective strategies to mitigate the adverse effects of specific toxicants are underlined for future studies.

Pulmonary exposure of mice to ammonium perfluoro(2-methyl-3-oxahexanoate) (GenX) suppresses the innate immune response to carbon black nanoparticles and stimulates lung cell proliferation

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) have been associated with respiratory diseases in humans, yet the mechanisms through which PFAS cause susceptibility to inhaled agents is unknown. Herein, we investigated the effects of ammonium perfluoro(2-methyl-3-oxahexanoate) (GenX), an emerging PFAS, on the pulmonary immune response of mice to carbon black nanoparticles (CBNP). We hypothesized that pulmonary exposure to GenX would increase susceptibility to CBNP through suppression of innate immunity.

METHODS

Male C57BL/6 mice were exposed to vehicle, 4 mg/kg CBNP, 10 mg/kg GenX, or CBNP and GenX by oropharyngeal aspiration. Bronchoalveolar lavage fluid (BALF) was collected at 1 and 14 days postexposure for cytokines and total protein. Lung tissue was harvested for histopathology, immunohistochemistry (Ki67 and phosphorylated (p)-STAT3), western blotting (p-STAT3 and p-NF-κB), and qRT-PCR for cytokine mRNAs.

RESULTS

CBNP increased CXCL-1 and neutrophils in BALF at both time points evaluated. However, GenX/CBNP co-exposure reduced CBNP-induced CXCL-1 and neutrophils in BALF. Moreover, CXCL-1, CXCL-2 and IL-1β mRNAs were increased by CBNP in lung tissue but reduced by GenX. Western blotting showed that CBNP induced p-NF-κB in lung tissue, while the GenX/CBNP co-exposed group displayed decreased p-NF-κB. Furthermore, mice exposed to GenX or GenX/CBNP displayed increased numbers of BALF macrophages undergoing mitosis and increased Ki67 immunostaining. This was correlated with increased p-STAT3 by western blotting and immunohistochemistry in lung tissue from mice co-exposed to GenX/CBNP.

CONCLUSIONS

Pulmonary exposure to GenX suppressed CBNP-induced innate immune response in the lungs of mice yet promoted the proliferation of macrophages and lung epithelial cells.

Translatability and transferability of in silico models: Context of use switching to predict the effects of environmental chemicals on the immune system

Immunotoxicity hazard identification of chemicals aims to evaluate the potential for unintended effects of chemical exposure on the immune system. Perfluorinated alkylate substances (PFAS), such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are persistent, globally disseminated environmental contaminants known to be immunotoxic. Elevated PFAS exposure is associated with lower antibody responses to vaccinations in children and in adults. In addition, some studies have reported a correlation between PFAS levels in the body and lower resistance to disease, in other words an increased risk of infections or cancers. In this context, modelling and simulation platforms could be used to simulate the human immune system with the aim to evaluate the adverse effects that immunotoxicants may have. Here, we show the conditions under which a mathematical model developed for one purpose and application (e.g., in the pharmaceutical domain) can be successfully translated and transferred to another (e.g., in the chemicals domain) without undergoing significant adaptation. In particular, we demonstrate that the Universal Immune System Simulator was able to simulate the effects of PFAS on the immune system, introducing entities and new interactions that are biologically involved in the phenomenon. This also revealed a potentially exploitable pathway for assessing immunotoxicity through a computational model.

Immunotoxicity mechanisms of perfluorinated compounds PFOA and PFOS

Perfluorinated and polyfluorinated compounds (PFASs) are a class of synthetic chemical substances that are widely used in human production and life, such as fire-fighting foams, textiles and clothing, surfactants, and surface protective agents. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are the most abundant and common perfluorinated compounds in biota and humans. Currently, PFOA and PFOS have been listed in the Stockholm Convention on Persistent Organic Pollutants, and their production has been halted in many countries. However, because the high-energy carbon-fluorine bond can make it resistant to hydrolysis, photolysis, microbial degradation, and vertebrate metabolism, PFOA and PFOS show environmental persistence and bioaccumulation and hence, are of great concern to humans and wildlife. PFOA and PFOS have toxic effects on the immune system of the body. This article reviewed the effects of PFOA and PFOS on immune organs such as the spleen, bone marrow, and thymus of mice and zebrafish, and the effects on non-specific immune functions such as the skin barrier, intestinal mucosal barrier, and humoral immunity. We also reviewed the influence of specific immune functions based on cellular immunity, and further summarized the possible immune toxicity mechanisms such as AIM2 inflammasome activation, gene dysregulation, and signal pathway disorders caused by PFOA and PFOS. The aim of this review was to provide a reference for further understanding of the immunotoxicity and the responsible mechanism of PFOA and PFOS.

Prevalence and Implications of Per- and Polyfluoroalkyl Substances (PFAS) in Settled Dust

PURPOSE OF REVIEW

Per- and polyfluoroalkyl substances (PFAS) are a family of more than 7,000 fluorinated compounds. The carbon-fluorine bond of PFAS provides desirable hydrophobic and oleophobic properties and stability that has led to widespread usage in consumer products and industrial applications. The strength of the carbon-fluorine bond also prevents appreciable degradation once released into the environment. Consequently, various household products can release volatile and nonvolatile PFAS into the indoor environment that often concentrate in dust. We discuss the diversity of PFAS in settled dust, emission sources of these chemicals, changes in PFAS profiles in dust over the past century, and the implications for human health.

RECENT FINDINGS

Sources of PFAS found in dust include building materials and furnishings and consumer products used in typical indoor spaces. Daycares and workplaces are emphasized as locations with widespread exposure due to the presence of treated carpeting and industrial-strength cleaners. Comparison and interpretation of findings across studies are complicated by the different ways in which PFAS are screened across studies. We further discuss recent developments in non-targeted software for the comprehensive annotation of PFAS in indoor dust and emphasize the need for comprehensive and harmonized analytical workflows. We highlight the detection and diversity of PFAS in settled dust collected from various indoor spaces, including locations with vulnerable subpopulations. There are opportunities for future research to leverage settled dust as a sentinel environmental matrix to evaluate the link between inhalation and ingestion routes of PFAS exposure to adverse health.

Serum vaccine antibody concentrations in adults exposed to per- and polyfluoroalkyl substances: A birth cohort in the Faroe Islands

Per- and polyfluoroalkyl substances (PFASs) are highly persistent in the environment and may cause depressed immune function. Previous studies have linked PFAS exposure to lower vaccine responses in children, but research in adults is limited. Therefore, the present study evaluated the associations between exposure to PFASs and serum antibody concentrations in adults vaccinated at age 28 years in the Faroe Islands. PFAS concentrations were determined from cord-blood collected at birth and serum samples collected at ages 7, 14, 22, and 28 years. Serum antibody concentrations against hepatitis type A and B, diphtheria, and tetanus were analyzed from blood samples collected about 6 mo after the first vaccine inoculation at age 28 years. Linear regression models were used to estimate changes in antibody concentration for each doubling of PFAS concentration. Potential effect modification by sex was assessed by including an interaction term between PFAS and sex. Although the 95% confidence intervals contain the null value, inverse trends were observed between serum perfluorooctanoate (PFOA) at ages 14 and 28 years and hepatitis type A antibody (anti-HAV) concentrations, as revealed by an estimated decrease of 0.71 (95% CI: -1.52, 0.09) and 0.24 (95% CI: -0.59, 0.10) signal-to-cutoff ratio for each doubling of exposure, respectively. Inverse trends were also observed between serum PFOA at ages 22 and 28 years and hepatitis type B antibody (anti-HBs) concentration, with an estimated decrease of 21% (95% CI: -42.20%, 7.34%) and of 17% (95% CI: -35.47%, 7.35%) in anti-HBs for each doubling of exposure, respectively. Sex-specific associations with anti-HAV were observed for cord-blood PFASs and serum PFAS concentrations at ages 7 and 14 years. No inverse associations of PFAS exposure were found with diphtheria and tetanus antibody concentrations. Future studies are needed to confirm these findings and further investigate the effects of PFASs on adult immune function.

Integrating in silico with in vivo approach to investigate phthalate and bisphenol A mixture-linked asthma development: Positive probiotic intervention

The aim of this study was to explore the mechanisms of bis(2- ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP) and bisphenol A (BPA) mixture-induced asthma development and test probiotic as a potential positive intervention. Comparative Toxicogenomics Database (CTD) and ToppGene Suite were used as the main tools for in silico analysis. In vivo 28-day experiment was conducted on rats - seven groups (n = 6): (1) Control: corn oil, (2) P: probiotic (8.78 * 10⁸ CFU/kg/day); (3) DEHP: 50 mg/kg b.w./day, (4) DBP: 50 mg/kg b.w./day, (5) BPA: 25 mg/kg b.w./day; (6) MIX: DEHP + DBP + BPA; (7) MIX + P. Lungs, thymus and kidneys were extracted and prepared for redox status and essential metals analysis. By conducting additional in vitro experiment, probiotic phthalate and BPA binding ability was explored. There were 24 DEHP, DBP and BPA asthma-related genes, indicating the three most probable mechanisms - apoptosis, inflammation and oxidative stress. In vivo experiment confirmed that significant changes in redox status/essential metal parameters were either prominent, or only present in the MIX group, indicating possible additive effects. In vitro experiment confirmed the ability of the multy-strain probiotic to bind DEHP/DBP/BPA mixture, while probiotic administration ameliorated mixture-induced changes in rat tissue.

Perfluoroalkyl substances exposure and immunity, allergic response, infection, and asthma in children: review of epidemiologic studies

Background

Increased exposure to perfluoroalkyl substances (PFAS) potentially affects infant and childhood health through immunosuppression. Given rapidly evolving research on PFAS, it is important to comprehensively examine the impact of PFAS exposure among the pediatric population as new research becomes available due to potential fragility of the developing immune system.

Objectives

This review assessed the effects of PFAS fetal, infant and childhood exposures upon the development of immune function during early life stages.

Methods

Researchers completed a literature review, searching PubMed for human studies published since 2010 for PFAS and health outcomes among infants and children. Included articles incorporated key search terms in the title or abstract; non-research reports and non-English papers were excluded. The search identified 518 studies for possible inclusion. Following hands-on review, 34 were determined relevant. Subsequent analyses found 8 additional relevant articles, totaling 42 studies.

Results

Major immune-related sequelae from PFAS exposures on infant and child health outcomes documented in recent literature include:

• Strong indication of immunosuppression, with diminished childhood antibody response to vaccination, particularly with PFOA, PFOS and PFHxS exposures.

• Some indication of increased risks of childhood infectious diseases/infections, particularly from PFOS exposures.

• Limited indication of an effect of PFAS exposure on allergic reactions/allergen specific IgE antibodies.

• Limited indication of an effect of PFAS exposure on atopic dermatitis (AD).

• Limited indication of an effect of PFAS exposure on asthma and lung function.

Conclusion

This review summarizes recent findings of PFAS effects on infant and childhood immune health. Evidence of immunosuppression, diminished vaccine efficacy, and increased risk of infections, allergies, asthma and AD were described following in utero, infant, and early childhood PFAS exposures. Further investigation is warranted to characterize PFAS exposure pathways and potential modes of action in relation to PFAS effects on the developing immune system. Incontrovertible proof of PFAS immunotoxic effects could optimally be obtained by a large prospective study cohort of mothers and children from infancy through school-age. Regular assessments of circulating antibodies and response to infant and childhood vaccines during growth years could prove invaluable.

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This review summarizes findings of PFAS effects on infant and child immune health.

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In utero, infant, and early childhood PFAS exposures were examined.

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Strong evidence of PFAS exposure on diminished childhood antibody vaccination response.

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Moderate evidence of PFAS exposure on increased risk of childhood infectious diseases.

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Limited evidence of PFAS exposure on allergic reactions, atopic dermatitis, asthma.

Perfluorooctane sulfonate and bisphenol A induce a similar level of mast cell activation via a common signaling pathway, Fyn-Lyn-Syk activation

Perfluoroalkyl compounds (PFCs) as food contaminants are widely distributed persistent organic pollutants (POPs) and have been suggested to induce immune dysfunction. However, their effects on immune function are not conclusive. Mast cells play a central role in allergic and non-allergic inflammatory responses. Therefore, we have examined the effects of PFCs (PFHxS, PFOA, PFOS) on mast cell-mediated inflammatory responses using in vitro mouse bone marrow-derived mast cells (BMMCs) and human mast cells (HMC-1) and in vivo mice model. The effects of PFCs were compared with those of bisphenol A (BPA), a well-studied environmental pollutant. Among PFCs tested, PFOS had the highest effects. Both PFOS and BPA increased degranulation and production of inflammatory eicosanoids in mast cells at a similar level, which subsequently led to increased skin edema and serum LTC₄ and PGD₂ in mice. Both PFOS and BPA increased not only downstream signaling (PLCγ1, AKT, ERK), but also upstream signaling (Fyn, Lyn, Syk/LAT) in mast cells. Taken together, PFOS and BPA induce mast cell-mediated inflammatory responses via a common signaling pathways. Our results may help establish the scientific basis for understanding the etiology of mast cell-mediated inflammatory responses and improve the immune dysfunction risk assessment for emerging POPs such as PFCs.

Association between exposure to polyfluoroalkyl chemicals and increased fractional exhaled nitric oxide in adults

BACKGROUND

Perfluoroalkyl chemicals (PFCs) are widely detected in the environment and human body, and they have been linked to asthma and a number of respiratory responses in children and mice. However, no previous studies have investigated the association between exposure to PFCs and airway inflammation in adults.

OBJECTIVES

To evaluate the associations between serum PFCs and fractional exhaled nitric oxide (FeNO), a biomarker of airway inflammation, in adults.

METHODS

A cross-sectional study of 3630 adults aged 20-79 years who participated in the National Health and Nutrition Examination Survey (NHANES, 2007-2012) was conducted. Serum concentrations of five major PFCs were measured using SPE-HPLC-TIS-MS/MS method, including perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorodecanoic acid (PFDE). The detection rates of them were all >85%. Weighted multivariable linear regression and Bayesian kernel machine regression (BKMR) analyses were applied to examine the associations between serum PFCs and FeNO.

RESULTS

After adjusted for potential confounding factors, linear regression analyses found that compared with their lowest tertiles, highest tertiles of PFOS, PFDE and PFOA were significantly associated with 5.02% (95% CI: 1.40%, 8.77%), 3.77% (95% CI: 0.30%, 7.36%) and 6.34% (95% CI: 2.81%, 10.01%) increases in FeNO, respectively. The second tertile of PFNA was significantly correlated with a 4.79% (95% CI: 1.41%, 8.29%) increase in FeNO compared with the lowest tertile. In the BKMR analysis, the mixture effect of PFCs on FeNO increased significantly when the PFC levels were at or above the 60th percentiles compared to those at their medians. PFOS and PFOA displayed significant positive single-exposure effects on FeNO when all the other PFCs are set at a particular threshold.

CONCLUSIONS

This study provided preliminary evidence that serum PFCs were positively associated with increased FeNO in adults.