Mouse experiment may offer hope in Alzheimer's research

ST. LOUIS -- Brain cells in mice recovered rapidly after brain plaques characteristic of Alzheimer's disease were removed, offering hope that plaque-clearing treatments could benefit patients with the disease, Washington University researchers said Thursday.

No one knows for sure if the sticky plaque -- amyloid beta peptide -- is the true cause of Alzheimer's. But the plaque is a prime suspect, and several companies are developing drugs to target the buildup.

Researchers at Washington University injected mice with an antibody that cleared plaque in parts of the brain. Where the plaque was cleared, swelling on nerve cell branches disappeared quickly, the researchers said. They cautioned that while encouraging, more studies are needed to determine if similar effects might occur in people.

Removing the plaque "often led to rapid recovery of normal structure over a few days," said Dave Holtzman, senior author of the study and head of the Department of Neurology at Washington University.

He said that confirmed benefits of plaque-clearing treatments and "also gets us rethinking our theories on how plaques cause nerve cell damage."

Researcher Robert Brendza said he had expected the progression of cell damage to stop once the plaque was cleared. "But what we saw was much more striking: In just three days, there were 20 to 25 percent reductions in the number or size of the existing swellings," he said.

The rapid ability of the nerve cells to regain their normal structure could indicate that the cells are constantly trying to restore their normal structure, the researchers said.

Dr. Sam Gandy, director of the Farber Institute for Neurosciences at Thomas Jefferson University in Philadelphia and vice chairman of the Chicago-based Alzheimer Association's Medical and Scientific Council, called the finding "a pretty exciting advance."

"It shows that one of the long-standing structural abnormalities that was used to really define the disease is not something that's permanent and in fact it's reversible," Gandy said.

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