Vaccine may control Alzheimer's


Researchers have developed an experimental vaccine against Alzheimer's disease, a leading cause of dementia, which affects up to 20 per cent of the population over the age of 75. Scientists in Canada and the US have demonstrated the vaccine's ability to clear microscopic clumps (plaque) of a protein called beta amyloid from the brain of mice. This amyloid protein is thought to be at the centre of the disease process leading to Alzheimer's.

The mice were genetically modified to reproduce some of the symptoms of dementia.

The latest research has found that the vaccine not only clears the plaque from the central nervous system but was able in some way to prevent further mental decline among the mice. The vaccine, which has been developed by a subsidiary of Elan Pharmaceuticals, is a version of the beta amyloid protein itself.

It appears to capitalise on the fact that the brain and the body have separate immune systems. The vaccine stimulates the body's immune system to produce enough antibodies for some to migrate to the brain and begin attacking the beta amyloid at the point where it is doing damage.

There are a number of caveats, however. The science of a vaccine being effective against a non-viral agent such as a protein is certainly new. And there are other rogue proteins, apart from amyloid, associated with Alzheimer's.

Most importantly, there are significant differences between humans and mice. Even if this does turn out to be a significant step forward in the treatment of Alzheimer's disease, it will be at least five years before a vaccine is available to patients.