麻豆传媒

San Francisco

NICOTINE may prevent the lumping together of protein into the clumps that
are suspected of killing brain cells in Alzheimer鈥檚 disease, according to
chemists in Ohio. Experts say that the work, which was partially funded by the
tobacco industry, is interesting but very preliminary.

The brains of Alzheimer鈥檚 patients are often riddled with 鈥減laques鈥� of a
protein known as &bgr;-amyloid. Some biologists believe that the disease begins when
the normally soluble protein forms plaques that choke key nerve cells.

The controversial idea of nicotine as a treatment for the disease has
surfaced before. Some studies have found that smokers are less likely to develop
Alzheimer鈥檚 than nonsmokers. Others have suggested that nicotine鈥檚 ability to
switch on neurons may stimulate mental function and keep neurons alive. But Mark
Zagorsky, a chemist at Case Western Reserve University in Cleveland, Ohio,
wondered whether nicotine鈥檚 protective influence may start even earlier鈥攊n
its ability to stop the aggregation of the &bgr;-amyloid protein.

To test his idea, Zagorsky and his student Arthur Salomon found that if they
left &bgr;-amyloid in water it clumped into plaques within a few days. But if
nicotine was added to the solution, none of the protein aggregated and formed a
plaque. The researchers report their findings in last week鈥檚 issue of
Biochemistry.

鈥淚t鈥檚 an interesting result that needs to be pursued as a possibility,鈥� says
Zaven Khachaturian of the Alzheimer鈥檚 Association, which also helped to fund the
research. But he says one problem with targeting drugs against &bgr;-amyloid is that
its role in the disease is still unproven. Some patients with extreme dementia
have few plaques, while others with mild dementia may have many. 鈥淚t would be a
big leap of faith right now to say that a plaque inhibitor may have a use in
treating Alzheimer鈥檚.鈥�