Early development PFOS exposure may affect behavior and Alzheimer’s disease biomarkers in middle-aged mice, according to findings by STEEP researchers

Former STEEP trainee Emily Marques (left) and STEEP researcher Angela Slitt, photographed at a conference in 2019. Credit: Slitt Lab.

STEEP researcher Angela Slitt, former STEEP trainee Emily Marques, and colleagues from URI investigated a prevalent PFAS compound as a potential risk factor for Alzheimer’s disease. In a study published in Neurotoxicology, the scientists exposed mice and live cultured human cells to perfluorooctanesulfonic acid (PFOS) and assessed its effects on Alzheimer’s disease biomarkers and mouse behavior.

PFOS, one of the most widespread PFAS compounds, was commonly used in products like stain-resistant fabrics, food packaging, and fire-fighting foams. It has been detected throughout the environment and in human blood. Previous research using rodents as models has demonstrated neurological effects of PFOS exposure, leading to cognitive and behavioral abnormalities. Slitt, Marques, and their colleagues exposed the mice in their study to PFOS during pregnancy and through the mother’s milk, which mirrors how humans are often exposed to PFAS compounds early in life. When the mice were one-year old, which is considered middle-aged, their behavior was tested in a maze and in an open area. Although their ability to escape the maze was not affected by PFOS, the mice exposed to PFOS showed more anxiety-like behavior when placed in the open area. Altered behavior supports the idea that PFOS could potentially be causing neurological harm.

When the researchers looked at the live human cell cultures, they found that PFOS exposure altered certain proteins in ways consistent with Alzheimer’s disease. The effects on two biomarkers, tau protein and glycogen synthase kinase-3 beta, suggest that even low doses of PFOS can promote the development of Alzheimer’s disease.

About 60-80% of dementia cases worldwide are caused by Alzheimer’s disease. While one known gene is associated with late-onset Alzheimer’s disease, scientists believe there may be environmental risk factors as well. PFOS is a potential neurotoxin that is widespread and extremely difficult to break down. This investigation into its biological effects on live animals and human cells will help scientists understand if PFOS leads to Alzheimer’s in humans.

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