MADRID, July 17 (UPI) -- The drug donepezil seems to slow brain shrinkage in some patients with mild cognitive impairment, a pre-Alzheimer's symptom.
A new study that measured the rate of brain shrinkage in these patients using magnetic resonance imaging showed that 131 patients who carried the molecule APOE 4 -- a predictor of which patients will develop beta amyloid brain plagues, the primary marker of Alzheimer's -- and who took the drug donepezil had less shrinkage of the brain's hippocampus, the area that is key to memory function, compared to those taking placebo.
"No drug has been shown to slow brain atrophy for patients with mild cognitive impairment," says Clifford Jack Jr., a Mayo Clinic radiologist who led the study. "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."
Other drugs in the same class as donepezil have not yet been tested using MRI to see if they also slow brain shrinkage, researchers noted.
However, scientists are still baffled as to why the drug has an effect only in patients who carry APOE 4. "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," Jack said.
Moreover, the presence of APOE 4 is not a definitive predictor of the brain disease, he added. "Being an APOE 4 carrier increases one's risk for Alzheimer's disease, but many people who are carriers live into their 90s and don't get Alzheimer's," Jack noted.
The findings were presented Monday at the Alzheimer's Association International Conference on Alzheimer's disease and Related Disorders in Madrid.
