PFAS compounds are widely used in industrial applications and consumer products, prized for their durability and resistance to heat, water, and oil. However, their chemical stability also means they persist in the environment and accumulate in human tissue, earning them the nickname “forever chemicals.” Of particular concern is PFAS’s established capacity to disrupt immune function, which may underlie associations with various health disorders, including respiratory diseases like asthma. While earlier epidemiological studies have explored the relationship between PFAS and asthma, they generally focused on populations exposed only to background levels of these chemicals, yielding inconclusive results.

The latest breakthrough study leverages a unique natural experiment from Ronneby, Sweden, where municipal water contamination by PFAS reached extraordinarily high levels over decades due to industrial pollution. This localized exposure hotspot offered researchers an unparalleled opportunity to examine the effects of substantial prenatal PFAS exposure on childhood asthma incidence. By examining all children born in Blekinge County, including Ronneby, from 2006 to 2013, and linking maternal residential addresses with water distribution records, investigators could quantitatively estimate each child’s prenatal exposure level with unprecedented precision.

Coupled with nation-wide health registries documenting clinically diagnosed asthma cases, this register-based cohort design enabled robust statistical analyses correlating prenatal PFAS exposure with respiratory outcomes in children. The results were striking: children whose mothers experienced very high PFAS exposure levels during pregnancy exhibited significantly increased incidence of asthma during childhood. This association was absent at lower exposure levels, illuminating why previous studies in general populations failed to detect clear patterns.

The implications of these findings resonate deeply with global environmental health concerns. PFAS contamination is widespread, arising from sources such as aqueous film-forming foams used at airports, firefighting sites, and various industrial operations. The new evidence suggests that prenatal exposure to elevated PFAS concentrations may have lasting consequences on respiratory health, potentially contributing to increasing asthma burdens observed worldwide. This elevates PFAS pollution from an environmental nuisance to a pressing public health crisis with intergenerational impacts.

Analyzing the mechanisms behind this association, PFAS molecules are known to interfere with immune regulation by modulating cytokine production and altering immune cell function. Such immunotoxic effects may predispose developing fetuses to aberrant lung immune development, rendering them susceptible to asthma and other allergic airway diseases. The timing of exposure during critical windows of lung and immune system maturation in utero likely explains the heightened vulnerability observed in this cohort.

Nevertheless, the study authors caution that future research is needed to refine understanding of exposure-response relationships, taking into account confounding variables such as concurrent exposures to other environmental contaminants, postnatal PFAS exposure, and household smoking, all of which can influence asthma risk. The findings from Ronneby warrant replication in other highly exposed populations globally to validate the generalizability of these alarming results.

From a public health perspective, these insights underscore the urgent necessity to mitigate PFAS contamination through regulatory interventions, remediation of polluted water systems, and surveillance of at-risk communities. Policymakers must prioritize controlling PFAS emissions to prevent further prenatal exposure and its downstream health consequences. Additionally, clinicians should be aware of environmental factors contributing to asthma to better tailor prevention strategies and early interventions.

This study also exemplifies the power of leveraging population-based registries and environmental monitoring data for environmental epidemiology research. By melding detailed residential histories with medical outcomes and exposure metrics, researchers can unravel complex links between chemical pollutants and chronic diseases, guiding evidence-based policy and health recommendations.

In conclusion, the emerging science compels a reassessment of PFAS chemicals beyond their industrial utility, spotlighting them as significant prenatal hazards contributing to the asthma epidemic. As contamination affects millions worldwide, these findings sound a clarion call for intensified research, regulation, and remediation efforts to protect future generations from the insidious legacy of PFAS. The scientific and public health communities are now tasked with translating such revelations into tangible actions to curb this growing environmental health threat.

Subject of Research: People

Article Title: Prenatal exposure to per- and polyfluoroalkyl substances (PFAS) and incidence of asthma and wheeze in childhood: A register-based cohort study in Ronneby, Sweden

News Publication Date: Not provided

Web References: http://dx.doi.org/10.1371/journal.pmed.1004659

References: Blomberg AJ, Nielsen C, Borgström Bolmsjö B, Bind M-A, Hartman L, Saxne Jöud A (2026) Prenatal exposure to per- and polyfluoroalkyl substances (PFAS) and incidence of asthma and wheeze in childhood: A register-based cohort study in Ronneby, Sweden. PLoS Med 23(4): e1004659.

Image Credits: Robina Weermeijer, Unsplash (CC0)

Keywords: Asthma, PFAS, Prenatal Exposure, Childhood Respiratory Health, Environmental Contaminants, Immunotoxicity, Epidemiology, Water Contamination, Public Health, Synthetic Chemicals, Chronic Disease, Register-based Cohort Study

While the spotlight has traditionally focused on a group of well-known ‘legacy’ PFAS such as perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorohexane sulfonate (PFHS), which are already regulated under the 2001 Stockholm Convention on Persistent Organic Pollutants, the chemical landscape continues to evolve. New generations of PFAS have emerged in the market, often touted as safer alternatives. However, recent cutting-edge research underscores that these newer compounds may not be as benign as initially hoped. In a groundbreaking study published in the journal Frontiers in Aging, scientists have unveiled the concerning biological effects of two such compounds, perfluorononanoic acid (PFNA) and perfluorooctanesulfonamide (PFOSA), which appear to accelerate the aging process at a cellular level.

Dr. Xiangwei Li, a professor at Shanghai Jiao Tong University School of Medicine and the principal investigator of the study, emphasized the significance of these findings. “Our research demonstrates that specific forever chemicals, namely PFNA and PFOSA, expedite biological aging, especially in men aged between 50 and 64,” Li stated. He further cautioned that the assumption of newer PFAS as low-risk replacements is misguided, suggesting a pressing need to reevaluate regulatory frameworks to encompass these evolving contaminants. The study offers a lucid perspective on how these substances can insidiously disrupt biological systems, leading to accelerated aging and potential health complications.

The research team leveraged a robust data source—the US National Health and Nutrition Examination Survey (NHANES)—which provides a comprehensive, nationally representative cohort of older adults enrolled around the turn of the century. Blood samples from 326 participants were analyzed for concentrations of 11 different PFAS compounds. Notably, the team employed DNA methylome profiling, a sophisticated epigenetic technique that quantifies DNA methylation patterns controlling gene expression. By integrating these epigenetic markers into state-of-the-art algorithms known as ‘epigenetic clocks,’ they estimated the biological age of each individual, revealing a nuanced relationship between PFAS exposure and the pace of biological aging.

Intriguingly, the researchers discovered that PFNA and PFOSA were present in the blood of an overwhelming 95% of participants, signaling their pervasive nature. More critically, elevated levels of these chemicals correlated strongly with accelerated epigenetic aging in middle-aged men but not in women. This sexual dimorphism in response raises compelling questions about underlying mechanisms, possibly related to differences in metabolism, hormone regulation, or lifestyle factors that may amplify vulnerability. PFNA and PFOSA, synthesized originally between the 1950s and 1960s, find extensive application in consumer and industrial products due to their exceptional durability against heat, corrosion, and various forms of contamination.

Other PFAS compounds, including two acetic acid derivatives—2-(N-ethyl-perfluorooctane sulfonamido) acetic acid (EPAH) and 2-(N-methyl-perfluorooctane sulfonamido) acetic acid (MPAH)—as well as PFOS, PFOA, and PFHS, were also highly prevalent, detected in at least 85% of the subjects. However, the study interestingly found no significant association between these compounds and biological age, nor any gender or age-related variations in their concentrations. These findings imply compound-specific differences in biological impact, underscoring the complexity of PFAS chemistry and toxicology.

The team concluded that the effects of PFAS on epigenetic aging are not uniform across all compounds, pointing to the inadequacy of current regulations that primarily target legacy PFAS. Most notably, they argued for urgent regulatory attention to include compounds like PFNA and PFOSA, which remain largely overlooked in policy discussions despite emerging evidence of their harmful effects. As the landscape of chemical manufacturing continues to evolve, the need for dynamic, evidence-based oversight mechanisms that consider newer contaminants becomes paramount.

A particularly compelling aspect of the study is the age and gender-specific vulnerability highlighted. Middle-aged men, it seems, represent a uniquely sensitive demographic in the context of PFAS-induced aging. Dr. Ya-Qian Xu, the first author of the study, elucidated this pattern by pointing to midlife as a critical biological window. During this period, physiological systems become increasingly susceptible to various stressors—including chemical exposures—which may exacerbate aging processes. Dr. Li supplemented this view, hypothesizing that lifestyle factors more prevalent in men, such as smoking, might synergize with PFAS effects to accelerate biological wear and tear.

Globally, the regulatory environment is beginning to address PFAS concerns more proactively. France has already enacted a nationwide ban on PFAS usage in clothing and cosmetics, while the European Union considers imposing similar restrictions on select applications. These proactive measures reflect a growing recognition of the urgent need to mitigate exposure risks through legislative means. Experts advocate for further initiatives, urging manufacturers, policymakers, and consumers alike to prioritize reducing PFAS dissemination via industrial processes and product formulations.

In the interim, individuals can adopt practical strategies to reduce their PFAS exposure. The study’s authors recommend minimizing consumption of packaged foods, which often involve PFAS-laden materials, and avoiding practices like microwaving food in fast-food containers, which can increase chemical leaching. These measures, albeit small, contribute to limiting cumulative toxicity over time. Looking forward, the research team aims to expand investigations into how PFAS interact with other prevalent environmental pollutants to better elucidate the complex, cumulative health implications of these chemical mixtures.

This research not only deepens the understanding of PFAS toxicity but also exemplifies the power of epigenetics as a tool to measure and interpret the biological consequences of environmental exposures. By linking chemical pollutants with accelerated aging signatures, the study provides compelling evidence that could reshape public health policies and environmental standards. The pressing challenge remains: how to balance industrial and consumer benefits of these durable chemicals against their insidious and far-reaching biological costs. As this body of evidence grows, it becomes increasingly clear that the covert legacy of forever chemicals demands sustained scientific and regulatory vigilance.

Subject of Research: People
Article Title: Not specified in the provided content
News Publication Date: Not specified, but article publication date: 26-Feb-2026
Web References: https://www.frontiersin.org/journals/aging/articles/10.3389/fragi.2025.1722675/full
References: Not provided
Image Credits: Not provided
Keywords: PFAS, perfluorononanoic acid, PFNA, perfluorooctanesulfonamide, PFOSA, biological aging, epigenetic clock, DNA methylome, environmental toxicology, gender differences, middle-aged men, persistent organic pollutants

The liver’s critical role in detoxifying the bloodstream makes it exceptionally vulnerable to toxic insults from PFAS. These “forever chemicals,” as they are often termed due to their resistance to degradation, accumulate over many years, raising concerns about long-term health consequences including liver damage and metabolic disruptions. Despite epidemiological evidence linking PFAS exposure to liver abnormalities, including steatosis and cancer, the precise cellular and molecular mechanisms remained incompletely understood until now, largely due to limitations in traditional animal and cell culture models.

To overcome these challenges, researchers turned to human liver spheroids—a sophisticated three-dimensional culture system that closely mimics the architecture and microenvironment of the human liver. Made from cells pooled from multiple donors, these spheroids preserve critical cell-cell interactions that drive normal liver functions and pathological responses. This platform allowed for a nuanced investigation into the effects of four prevalent PFAS compounds—perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), perfluorooctanesulfonic acid (PFOS), and perfluorononanoic acid (PFNA)—each tested independently to discern their unique toxicity profiles.

After a continuous seven-day exposure of liver spheroids to these PFAS compounds, researchers employed advanced single-cell RNA sequencing to unravel gene expression changes at an unprecedented resolution. This technique revealed that while all four PFAS disrupt immune signaling pathways and interfere with intercellular communication—processes essential for liver homeostasis—their downstream effects diverged significantly. For instance, PFOA and PFHxS both promoted abnormal fat accumulation in liver cells, yet they achieved this through distinct mechanisms: PFOA stimulated de novo lipogenesis, increasing fat synthesis, whereas PFHxS inhibited fat metabolism, causing retention of lipids within cells.

Conversely, exposure to PFOS and PFNA led to gene expression patterns linked to oncogenic transformation. Notably, PFNA demonstrated a pronounced effect in activating pathways associated with inflammation, oxidative stress, and DNA repair mechanisms—hallmarks of cellular stress that can precipitate malignant transformation. The startling discovery that 61.3% of PFNA-exposed liver cells exhibited cancer-related gene signatures underscores the grave risk this compound poses to liver health, potentially accelerating the progression towards hepatocellular carcinoma.

Intriguingly, the study uncovered sex-specific differences in liver cell responses to PFAS exposure. Female-derived liver cells exhibited heightened sensitivity to PFOA, whereas male-derived cells were more affected by PFOS. These findings hint at underlying biological pathways modulated differently across sexes, suggesting the need for sex-informed strategies in both risk assessment and therapeutic development. Such differential susceptibility could be rooted in hormonal influences, enzyme expression profiles, or genetic regulatory networks that modulate PFAS metabolism and cellular stress responses uniquely in males and females.

The implications of this research extend far beyond the laboratory. By illuminating the precise cellular pathways disrupted by individual PFAS compounds, the study provides a critical foundation for the design of targeted interventions. Some pharmaceutical agents that modulate lipid metabolism and inflammation—already approved by the U.S. Food and Drug Administration—emerge as promising candidates for repurposing to ameliorate PFAS-induced liver toxicity. This represents a pivotal step towards translating mechanistic insights into clinical therapies that can reduce the burden of PFAS-related liver diseases.

Yet, despite therapeutic optimism, the researchers emphasize that prevention remains paramount. Reducing PFAS exposure is critical given their pervasive presence and persistent nature. They advise practical measures such as consuming filtered water and avoiding products coated with PFAS, including nonstick cookware. Although regulatory efforts are underway globally, immediate individual actions offer a necessary line of defense against these insidious chemicals, whose harm continues to unfold silently within our bodies.

This investigation is part of the Southern California Superfund Research and Training Program for PFAS Assessment, Remediation and Prevention (ShARP Center), a multidisciplinary NIH-funded initiative committed to addressing the environmental and health challenges posed by PFAS contamination. By fostering collaboration across toxicology, environmental science, and public health, the ShARP Center aims to generate actionable knowledge and innovative solutions that can safeguard communities affected by PFAS pollution.

Future directions for this research involve exploring the combined effects of multiple PFAS compounds, reflecting real-world exposure scenarios where humans encounter complex mixtures rather than single substances. This line of inquiry is crucial because PFAS mixtures may exhibit synergistic or additive toxicities that differ from individual chemicals, further complicating risk assessment and regulatory standards. Understanding these interactions at the granular cellular level will be key to refining safety guidelines and developing effective mitigation strategies.

The technical achievements in this study—particularly the use of multi-donor human liver spheroids paired with single-cell transcriptomics—represent a breakthrough for toxicological research. This approach enables scientists to disentangle heterogeneous cellular responses, map molecular pathways with fine detail, and capture subtle variations linked to donor sex or genetic background. Such methodological innovations are setting new standards for environmental health research, transcending the limitations of animal models and traditional cell cultures.

As PFAS contamination continues to be a pressing environmental health issue worldwide, this research highlights the urgent need for informed public health policies and consumer awareness. The distinct molecular fingerprints left by different PFAS chemicals in liver cells not only clarify their individual toxicities but also underscore the complexity of their impact on human health. Accurate, mechanistic knowledge is indispensable for crafting nuanced regulations that protect vulnerable populations while guiding the development of medical interventions.

In sum, this comprehensive study advances our understanding of how perfluoroalkyl substances sabotage liver health at the most fundamental biological levels. Through innovative research techniques and a focus on translational impact, the USC team has transformed the opaque landscape of PFAS toxicity into a clearer map of cellular disruption, risk, and potential remedy. Their work will resonate across toxicology, medicine, and environmental science communities for years to come, fueling efforts to combat the global challenge posed by these persistent pollutants.

Subject of Research: Cells

Article Title: Assessing the impact of perfluoroalkyl substances on liver health: a comprehensive study using multi-donor human liver spheroids

News Publication Date: 5-Sep-2025

Web References:
https://www.sciencedirect.com/science/article/pii/S0160412025005148
http://dx.doi.org/10.1016/j.envint.2025.109763

References:
Maretti-Mira, A. C., Golden-Mason, L., Matsuba, C., Wang, Y., Salomon, M. P., Setiawan, V. W., & Chatzi, L. (2025). Assessing the impact of perfluoroalkyl substances on liver health: a comprehensive study using multi-donor human liver spheroids. Environment International, [DOI:10.1016/j.envint.2025.109763].

Keywords:
Liver damage, Liver cancer, Metabolic disorders, Chemical pollution, Water pollution, Pollutants, Fatty liver disease

Exposure to PFAS poses significant challenges, especially because they enter the human body through various pathways including contaminated food, drinking water, and air. While these compounds are not acutely toxic, chronic exposure is nearly unavoidable in modern societies. This sustained presence and bioaccumulation raise serious concerns about long-term health outcomes, particularly in vulnerable subpopulations such as pregnant women, young children, and individuals with chronic illnesses. Such groups may experience heightened risks due to the subtle but persistent effects of these chemicals.

Scientific investigations have uncovered associations between PFAS exposure and several detrimental health conditions, including metabolic disorders like obesity, disruptions in hormonal balance, and increased cancer risk. Beyond these effects, PFAS are now recognized as modulators of the immune system, a revelation that carries significant implications for public health. Recent epidemiological data highlight how PFAS compromise immune responses, notably by dampening antibody production following vaccination against infectious diseases, with SARS-CoV-2 being a prominent example.

Understanding the intricacies of the immune system’s response to PFAS exposure is critical, especially given the ongoing global challenges posed by COVID-19. Immunity against SARS-CoV-2 involves both humoral immunity mediated by antibodies and cellular immunity driven by T cells and other immune components. While antibody levels have traditionally been used as a marker of vaccine effectiveness, they do not tell the entire story. The cellular arm of the immune response is equally vital for protection against severe infections but has been less studied in the context of PFAS exposure.

Addressing this knowledge gap, a collaborative research team led by Professor Ana Zenclussen from the Helmholtz Centre for Environmental Research (UFZ) conducted an in-depth experimental study focused on how PFAS influence cellular immune responses in individuals vaccinated against SARS-CoV-2. By isolating peripheral blood mononuclear cells (PBMCs) from vaccinated individuals with prior COVID-19 infection, the researchers were able to meticulously examine immune cell behavior when exposed to PFAS in laboratory conditions. This approach allowed for controlled analyses of direct effects, bypassing the complexity of whole-body interactions that often obscure mechanistic insights.

Central to the study’s design was the use of a PFAS mixture carefully calibrated to mimic real-world exposure levels observed across European populations. This mixture was developed in collaboration with Norwegian partners from the Institute of Public Health in Oslo and was derived from extensive cohort data to ensure ecological validity. To explore dose-dependent effects, the immune cells were also subjected to PFAS concentrations up to a thousand times higher, simulating exposure scenarios relevant to workers in PFAS production facilities.

Following a 24-hour incubation with the PFAS mixture, the PBMCs were then stimulated with SARS-CoV-2 spike proteins to evaluate their immune responsiveness. Cutting-edge spectral flow cytometry was employed to dissect the immune cell repertoire with high resolution, enabling quantification and identification of multiple immune subsets within a single assay. This technology also facilitated the measurement of cytokines and chemokines—immune signaling molecules that dictate cell communication and functional responses.

The results painted a nuanced and concerning picture. At elevated PFAS concentrations, two distinct types of immune cells displayed an exaggerated inflammatory response when re-exposed to SARS-CoV-2 antigens. This phenomenon, characterized by increased secretion of inflammatory mediators, suggests a dysregulated immune activation that may have harmful consequences if replicated in vivo. Intriguingly, this hyperinflammatory trend was markedly more pronounced in the samples derived from male participants, hinting at potential sex-specific vulnerabilities.

Conversely, female participants’ immune cells exhibited a different pattern. Higher PFAS exposure correlated with a reduction in B cell populations, the specialized lymphocytes responsible for producing antibodies and sustaining long-term immunity. Such depletion could undermine humoral immune memory and impair vaccine efficacy, raising important questions about sex-based differences in immune modulation by environmental contaminants.

Moreover, the production of key soluble immune mediators involved in recruiting other immune cells to the site of infection and in tissue repair processes was adversely affected across both sexes. These functional impairments further underscore the potential for PFAS to not only skew immune responses but also impede the resolution phase of inflammation, which is critical for restoring tissue homeostasis after viral challenges.

Collectively, these findings underscore the complexity of PFAS-induced immunomodulation and highlight the potential public health ramifications. Individuals experiencing high PFAS burdens—whether occupationally or environmentally—might face increased risks of suboptimal vaccine responses and more severe disease progression if infected with SARS-CoV-2 or similar pathogens. Tailoring vaccination strategies to account for such environmental exposures could become an essential component of personalized medicine and epidemiological planning.

Professor Ana Zenclussen emphasized the significance of these discoveries, noting that this research fills a crucial gap in understanding how chronic environmental pollutants alter cellular immunity. The sex-differentiated effects warrant further investigation to inform risk assessments and public health interventions that consider biological variability.

Dr. Oddvar Myhre of the Norwegian Institute of Public Health highlighted the methodological strengths of the study, particularly the use of human-relevant PFAS mixtures reflective of actual exposure scenarios. This approach moves beyond single-compound toxicology, embracing the complex interactions found in real-world PFAS contamination and its health consequences.

As PFAS contamination continues to be a pressing environmental and health issue globally, studies like this provide critical mechanistic insights that bridge laboratory findings with epidemiological trends. The integration of advanced immunological techniques, realistic exposure models, and interdisciplinary collaboration marks a new frontier in assessing how “forever chemicals” impact human health at the immune system level.

Future research directions should include long-term cohort studies tracking PFAS exposure alongside vaccine responsiveness and infection outcomes, stratified by sex and other demographic factors. Intervention strategies to reduce PFAS exposure and mitigate its immunotoxic effects should also be prioritized to protect vulnerable populations and enhance global health resilience.

Subject of Research: Cells
Article Title: Evaluating PFAS-Induced modulation of peripheral blood mononuclear cells (PBMCs) immune response to SARS-CoV-2 spike in COVID-19 Vaccinees
News Publication Date: 26-Mar-2025
Web References: 10.1016/j.envint.2025.109409

Keywords

PFAS, immune modulation, SARS-CoV-2, COVID-19 vaccination, cellular immunity, peripheral blood mononuclear cells, spectral flow cytometry, sex differences, environmental contaminants, chronic exposure, immunotoxicity, antibody response