Strategy Could Put Brakes on Alzheimer's

Doing so prevented the expected cognitive and neuronal deficits, the team report.

"Mice that had a brain full of amyloid could memorize things quite nicely," Mucke noted.

That effect was seen even when tau levels were cut in half, rather than completely eliminated.

At this point, the researchers aren't entirely sure how this strategy succeeds.

"We think tau reduction acts a little bit like a restrictor plate on a race care, which prevents it from spiraling out of control," Mucke explained. "That's what happens to some nerve cells when they become overexcited by amyloid protein or by a variety of other factors. This is 'excitotoxicity' -- too much excitation of nerve cells. Reducing tau seems to prevent that from happening."

Excitotoxicity has been implicated in a variety of neurological diseases. This paper also showed that reducing tau made mice less prone to having epileptic seizures, for instance.

"There are potentially broad applications," Mucke said.

"The fact that this implication involves three major morbidities (Alzheimer's, stroke, epilepsy) will undoubtedly make for a great synergy of effort, since it is conceivable that from any one line of research could emerge a truly broad spectrum neuroprotectant," Gandy added.

More basic research needs to be done before the strategy can be applied to humans, but Mucke believes it's a promising avenue.

"My view is that we are not going to treat Alzheimer's with one drug," he said. "It's very important that we don't put all our money into anti-amyloid treatment but that we diversify a little bit. I think tau is a worthy target."

More information

Learn more about Alzheimer's at the Alzheimer's Association.

SOURCES: Lennart Mucke, M.D., director, Gladstone Institute of Neurological Disease, and professor, neurology, University of California, San Francisco; Sam Gandy, M.D., Ph.D., chairman, Medical and Scientific Advisory Council, Alzheimer's Association, and director, Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia; May 4, 2007,Science