Older brains clear out plaque-forming amyloid beta more slowly
A new study may help explain why Alzheimer’s is a disease of aging.
A protein fragment that forms the brain cell–killing plaques characteristic of Alzheimer’s disease sticks around longer and longer as people age, researchers report July 20 in the Annals of Neurology. That persistence may make it easier for plaques to form in older people, says study coauthor Randall Bateman, a neuroscientist at Washington University School of Medicine in St. Louis.
Bateman and colleagues measured how long it takes for the protein fragment known as amyloid beta, or A-beta, to be cleared from people’s brains. Some A-beta may be broken down and some may be transported out of the brain. For a 20-something-year-old, it takes about four hours for half of the A-beta in the brain to disappear. But that half-life increases to nearly 10 hours for people in their 80s, the researchers found.