July 4, 1998 Amyloid Can Trigger Brain Damage By N. Seppa
Autopsies of Alzheimer's patients show waxy plaques of a protein
called beta-amyloid littering the brain like shrapnel on a
battlefield. Yet researchers have failed to establish whether
beta-amyloid actually causes the disease. Now, a study of
monkeys shows that beta-amyloid can indeed damage nerve cells,
or neurons, in the brain, especially in older animals. Some
researchers have suggested that an accumulation of amyloid
plaques over many years contributes to Alzheimer's disease,
which would help explain why the condition usually strikes the
elderly. The new study, however, shows that equal amounts of
beta-amyloid inserted into the brains of young and old monkeys
are far more destructive in the old ones. The work appears in
the July Nature Medicine. "This animal model shows that beta-
amyloid introduced into the brain at levels similar to that in
Alzheimer's disease can actually cause brain cell death," says
coauthor Bruce A. Yankner, a neurologist at