July 18, 2006
Alzheimer’s drug slow brain shrinkage
WASHINGTON (Reuters) - The Alzheimer's drug Aricept not
only improves memory and understanding in patients but appears
to slow the characteristic shrinkage of the brain, researchers
reported on Monday.
Magnetic resonance imaging or MRI images of the brains of
131 patients with mild cognitive impairment showed less
shrinkage of the hippocampus, a structure key to memory
function, in patients who got the drug compared to those who
got a placebo, researchers told a meeting.
"No drug has been shown to slow brain atrophy for patients
with mild cognitive impairment," said Dr. Clifford Jack of the
Mayo Clinic in Rochester, Minnesota.
Aricept, which is known generically as donepezil, is
marketed by Pfizer and Japan's Eisai Co. Ltd..
"Our study results seem to imply that donepezil does more
than provide symptom relief -- it has an effect on a measure of
brain health. Our findings also show that MRI measures can have
usefulness in future studies of mild cognitive impairment."
Mild cognitive impairment can lead to Alzheimer's disease,
but not always.
Jack's team found the effects only in people with the
apolipoprotein E4 (APOE 4) gene, a genetic variation that has
long been known to put people at higher risk of Alzheimer's.
Why is unclear, he said.
"One possibility is that APOE 4 carriers were more likely
to have definite Alzheimer's disease than noncarriers in the
study who appear to have symptoms of early Alzheimer's disease,
yet turn out to have a different diagnosis when an autopsy is
performed after death," he said.
Jack's study was presented to the International Conference
on Alzheimer's Disease and Related Disorders in Madrid, Spain.
An estimated 12 million people worldwide suffer from
Alzheimer's disease, but international researchers predict the
number of people suffering from dementia worldwide could reach
81 million by 2040 as the "baby boom" generation ages.
There is no cure for Alzheimer's, which begins as mild
memory loss and can progress quickly to complete loss of any
ability to care for oneself.
The brain becomes clogged with proteins known as plaques
and tangles of nerve fibers. And it shrinks.
"In extreme cases, the brain of an Alzheimer's patient
might weigh half of what a normal person's brain does at peak
health," Jack said.
Experts are looking for ways to prevent Alzheimer's from
developing, or to slow its fatal progression. They are also
looking for better ways to diagnose the disease in patients
using imaging scans such as MRI or PET.