Blood samples taken from people enrolled in an Alzheimer’s research study revealed higher levels of phosphorylated tau 217 that correlated with the presence of amyloid plaques. People with amyloid in their brains had up to three times more of the tau protein in their blood than those who had no evidence of amyloid accumulation. The higher levels of the protein were evident even in people with no signs of cognitive decline.
Two decades or more before symptoms arise, plaques of a sticky protein called amyloid begin forming in the brains of people later diagnosed with Alzheimer’s disease. Researchers at Washington University School of Medicine in St. Louis have shown that levels of a specific protein in the blood rise as amyloid plaques form in the brain. This protein can be detected in the blood of people who have yet to show signs of forgetfulness or confusion, making it a promising blood test to diagnose Alzheimer’s before symptoms appear.