Nicotine and Alzheimer's

WASHINGTON--Nicotine prevents the formation in the test tube of protein clumps linked to Alzheimer's disease, scientists announced at a press conference today. The finding may provide a useful starting point for developing drugs that delay or prevent the disease. The researchers are quick to caution, however, that harmful effects of smoking--strengthened by a report in Science last week linking a carcinogenic byproduct of cigarette smoke to a specific kind of lung tumor--far outweigh any possible benefit from nicotine in tobacco.

Michael Zagorski, a biochemist at Case Western Reserve University in Cleveland, and his colleagues were looking for a biochemical mechanism to explain why smokers appear to have a lower incidence of Alzheimer's. They found that nicotine prevents aggregation of beta amyloid, a protein that forms damaging plaques in Alzheimer's patients' brains. The researchers added nicotine to a solution of beta amyloid, which can take several shapes. They found that nicotine binds to the soluble protein and prevents it from aggregating in a form found in Alzheimer's plaques. The results of the study, which was partially funded by the tobacco firm Philip Morris, are published in this month's Biochemistry.

The findings are "intriguing," says neurobiologist Neil Buckholtz, director of Alzheimer's research at the National Institute on Aging. However, he points out, the concentrations of beta amyloid and nicotine in the study are much higher than levels in the brain. Still, nicotine or related compounds might someday be used as a drug to delay or prevent Alzheimer's, says Ken Keller, a pharmacologist at Georgetown University Medical Center. Don't expect nicotine to cure Alzheimer's, however. ``No one thinks nicotine is going to be a turnaround drug,'' Keller says.

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