ORLANDO, Fla. By studying a chemical marker in the brain that reflects the health of brain tissue, researchers at Duke University Medical Center have found new clues about why some people experience more rapid age-related brain changes than others.
The researchers have found an association between nerve cell changes associated with aging and the presence of a variation of the apolipoprotein gene known as apolipoprotein E4 (APOE4). This form is carried by approximately 25 percent of the population and has been linked to increased risk of Alzheimer's disease, cardiovascular disease and memory loss after head injury or bypass surgery.
Although the signs of age-related memory loss are widely recognized, researchers are still unsure why some elderly adults retain strong mental capacity well into their 90s while others fall into progressive decline or dementia.
"The frontal lobe is the site where the earliest and most consistent effects of aging occur in the brain," said P. Murali Doraiswamy, M.D., a psychiatrist at Duke and lead researcher on the study. "Virtually every mental symptom of normal aging results from decline in frontal lobe functions. When we examined this vital area of the brain by following a particular genetic marker, we found a single gene variation that can result in significant nerve cell changes associated with aging. Of the people we studied, those who carried the APOE4 gene experienced a more rapid loss of nerve cell functioning."
In other words, their brains showed signs of aging faster than those without the gene.
The research team was scheduled to present their findings today (Feb. 25, 2002) at the 15th annual meeting of the American Association for Geriatric Psychiatry in Orlando, Fla.
Doraiswamy's team decided to measure levels of N-acetylspartate (NAA), a brain chemical known to be closely associated to nerve cells, and hence to mental functions. This chemical is primarily found inside nerve cells within th
Contact: Tracey Koepke
Duke University Medical Center