A
new finding that may help unravel the Alzheimer's disease (AD) puzzle
shows that loss of enzymes associated with the production of acetylcholine,
a brain chemical implicated in memory function, may occur much later
in Alzheimer's disease than formerly believed.
Dr.
Kenneth Davis and colleagues at the Mount Sinai Alzheimer's Disease
Research Center in New York studied the brains after death of people
with early and late AD and people with no memory problems. The study
appears in the April 21, 1999, issue of the Journal of the American
Medical Association (JAMA).
The findings indicate that patients in early stages of the disease,
while exhibiting memory deficits and classic pathological signs,
such as plaques and tangles, have relatively normal levels of the
enzymes regulating acetylcholine levels. Only in patients with severe
Alzheimer's disease did they see much diminished levels of these
enzymes. These findings suggest that overall deficits of these enzymes
may not be an early pathological feature of the disease, although
they do not exclude the possibility that more subtle losses might
have occurred in specific neuron populations. Positive effects of
currently approved drugs on early-stage AD patients might not be
due to maintaining falling levels of acetylcholine but to boosting
normal levels of this important chemical.
The
National Institute on Aging (NIA) currently funds Alzheimer's disease
Centers at medical institutions around the nation. The NIA network
of centers has played a major role in advancing research on Alzheimer's
disease. The NIA is the lead federal agency supporting and conducting
Alzheimer's disease research, including studies of the basic, clinical,
and epidemiological aspects of this and other related dementias of
aging.
