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Monday, 6 November, 2000, 17:28 GMT
Alzheimer's: how mice beat it
Mouse brains could resist the development of Alzheimer's
The ability of mice to resist the development of Alzheimer's disease could be harnessed to help humans fight the disease, say scientists.

One of the key changes associated with the disabling and ultimately fatal brain disorder are the appearance of deposits of waste products building up in brain tissue.

These deposits, called "amyloid plaques" are believed to be toxic to surrounding brain cells, and contribute to the degenerative condition, which is frequently marked with symptoms such as confusion, sleeplessness and memory loss.

Elderly woman in wheelchair
Alzheimer's is predominantly a disease of the elderly
However, scientists have noticed that mice seem to be able to stop these plaques forming in their brains.

They have a body chemical which appears to help flush the waste material, beta amyloid, out of the brain, preventing it being laid down as a plaque.

This chemical, a protein called LRP-1, helps push the beta amyloid across the blood brain barrier, beyond which it is broken down into harmless constituents.

Neurosurgeon Berislav Zlokovic, from the University of Rochester Medical Center, tested the brains of live mice to test the role of LRP-1.

He stopped their brains producing the protein, then injected an amyloid chemical.

When LRP-1 production was blocked, the removal of amyloid from the brain slowed dramatically.

Zlokovic said: "The idea that healthy people have small amounts of amyloid peptide in their brains, and that somehow the body is constantly neutralising it, has been around for a while.

"But just how the body takes care of it has been a huge question mark."

Poor circulation

He believes that Alzheimer's may generally be a disease of the elderly because either the LRP-1 production slows down, or poor circulation to the brain stops the beta amyloid being flushed out.

Keeping active, either mentally or physically, is associated with a reduced risk of Alzheimer's.

Professor Simon Lovestone, a professor of old age psychiatry at the Institute of Psychiatry in London, said that the link between circulation and Alzheimers was a possibility.

He added: "This still remains to be proven. Not much is known about the reason many people get Alzheimer's."

Greater understanding of this process might help scientists devise ways of helping Alzheimer's patients, or all those at risk of the disease, boost this cleaning mechanism and prevent or slow down plaque formation.

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20 Jun 00 | Health
'First real test' for Alzheimer's
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