Stem Cell Loss in Aging Brain May Bring Poorer Memory
Rat study also suggests new treatments for Alzheimer's, experts say
FRIDAY, Dec. 22, 2006 (HealthDay News) -- Having trouble remembering things with age? A new study in rats finds that stem cells in aging brains divide less frequently, leading to a dramatic drop in the number of new nerve cells being born in the hippocampus, the brain's learning and memory center.
The finding, published in the journal Neurobiology of Aging, also suggests that it may be possible to stimulate the brain's ability to produce new brain nerve cells in order to treat neurodegenerative diseases such as Alzheimer's, depression and dementia, said senior study investigator Ashok K. Shetty, professor of neurosurgery at Duke University Medical Center in Durham, N.C., and a medical research scientist at Durham VA Medical Center.
For this study, the researchers attached fluorescent tags to neuronal stem cells in the hippocampus of young, middle-aged and old rats. In young rats, the hippocampus contained 50,000 stem cells. This number did not decrease with age, which means that decreased production of new neurons in aging brains is not related to a lack of stem cells.
The researchers then analyzed neuronal stem cell division in the rats and found that 25 percent of neuronal stem cells were actively dividing in young rats, compared with 8 percent in middle-aged rats and 4 percent in old rats.
"This discovery provides a new avenue to pursue in trying to combat the cognitive decline associated with conditions such as Alzheimer's disease and with aging in general," lead investigator Bharathi Hattiangady, a neurosurgery research associate at Duke, said in a prepared statement.
The researchers are now exploring methods of stimulating the brain to replace its own cells in order to improve memory and learning in the elderly.
The American Academy of Family Physicians has more about memory and aging.