Scientists close to finding a vaccine for dementia

A vaccine against Alzheimer's disease could soon a be reality after pioneering research showed that the long-term mental decline associated with the disease can be prevented.

A vaccine against Alzheimer's disease could soon a be reality after pioneering research showed that the long-term mental decline associated with the disease can be prevented.

Three independent teams of scientists have demonstrated in animal experiments that a vaccine can prevent the build-up of protein deposits in the brain which are believed to cause Alzheimer's.

Scientists have shown that it is possible to arrest the decline in the mental performance of laboratory mice that would otherwise be destined to develop similar symptoms to those of the human disorder. The scientists behind the research, which is published today in the journal Nature, believe the findings could be developed into an effective treatment for a disease that affects one in 20 people over the age of 65, and a third of those over 80.

Alzheimer's disease, which is sometimes unkindly called the "living death," is a seriously debilitating condition which is of growing concern for a country with a rapidly ageing population.

Peter St George-Hyslop, the director of the Centre for Neurodegenerative Diseases at the University of Toronto, where one of the three studies took place, said the findings were unequivocal. "Not only were we able to clean up the brain tissue, but we also prevented the behavioural consequences of Alzheimer's. Obviously, it is more important that a treatment or prevention in humans be able to block the clinical dementia," Dr St George-Hyslop said.

The vaccine was developed from a small protein, or peptide, that builds up in the brain of Alzheimer's patients to produce the tell-tale deposits or "plaques" that were thought to cause dementia.

Vaccinated mice had fewer plaques and were much better than unvaccinated animals at performing and remembering how to find an underwater platform when swimming in an enclosed tank - a classic test of mental ability in mice.

The other two studies which led to a similar conclusion came from a team led by scientists at Edinburgh University and a group led by the University of South Florida in Tampa.

Harry Clayton, chief executive of the Alzheimer's Society, said: "If the results of this study can be replicated in humans it means the serious possibility of an intervention that could treat or even prevent dementia developing.

"It really is a great step forward in our knowledge."