The negative health effects of chemicals called PFAS continue to be uncovered. Scientists from North Carolina State University (NCSU) have now shown that some types of PFAS can disrupt vital functions of immune cells.
Per- and polyfluoroalkyl substances (PFAS) are a broad group of chemicals that are becoming more and more problematic the more research is done on them. Since they were developed in the 1940s, their non-stick and water-repellent properties made them appealing for a range of uses in common household products.
It was only later that their health impacts became apparent. PFAS exposure has been linked to diabetes, low birth weight, fertility issues, thyroid disease, and various cancers, among other things. Worse still, their long life and abundance makes exposure hard to avoid.
In the new study, the NCSU team investigated the effects of nine different PFAS molecules on the innate immune system that hadn’t been well studied before. The team tested the PFAS against immune cells called neutrophils, some of the body’s first responders to infection, which fight by dumping reactive oxygen species onto pathogens in a process called respiratory burst.
Three groups of neutrophils were tested: some cultured from human blood samples, some derived from zebrafish embryos, and some from other cells that had been chemically treated to behave like neutrophils. Each group was exposed to solutions of the nine PFAS chemicals, all of which have been detected in the Cape Fear River in North Carolina, as well as the blood of people in the area.
One PFAS was particularly troublesome – GenX, a later chemical that was introduced to replace earlier, more toxic PFAS but was eventually discovered to have its own health concerns. In this case, GenX was found to disrupt the respiratory burst process in all three groups, potentially weakening the immune response to pathogens. A second PFAS, called PFHxA, was also found to suppress the process, but only in the zebrafish and neutrophil-like cells.
The team says that this study uncovers new concerns for these already problematic chemicals, but further work will need to be done to investigate how they might affect the innate immune system at levels that everyday people would be exposed to.
“The longest chemical exposure in our study was four days, so obviously we can’t compare that to real human exposure of four decades,” said Jeff Yoder, corresponding author of the study. “We looked at a high dose of single PFAS over a short period, whereas people in the Cape Fear River basin were exposed to a mixture of PFAS – a low dose over a long period. So while we can say that we see a toxic effect from a high dose in the cell lines, we can’t yet say what effects long-term exposure may ultimately have on the immune system.”
The research was published in the Journal of Immunotoxicology.
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