People with high levels of A-beta 42, one of the main components of the amyloid plaques associated with Alzheimer’s disease, are at significantly greater risk of developing the disease, according to results of a study by Nicole Schupf and colleagues.
The 4.5-year-long study of 1,125 people in their late 70s found that participants with the highest levels of A-beta 42 at the start of the study were more than three times as likely to develop Alzheimer’s disease as participants with the lowest levels of the peptide. Intriguingly, A-beta 42 levels were found to drop just before participants developed the first symptoms of the disease, possibly suggesting that A-beta 42 has been deposited in amyloid plaques in the brain.
The results suggest that monitoring blood levels of A-beta 42 in older people would provide scientists with a method of identifying those at high risk of developing Alzheimer’s disease. Sudden drops in A-beta 42 in high-risk patients undergoing regular monitoring may suggest that they have already developed the disease.
Schupf N, Tang MX, Fukuyama H, Manly J, Andres H, Mehta P, Ravetch J, Mayeux R. Peripheral Aβ subspecies as risk biomarkers of Alzheimer’s disease. PNAS Published September 8, 2008, doi:10.1073/pnas.0805902105.
