Alzheimer's vaccine proves successful in mice.

NEW YORK, Sep 28 (Reuters Health) - Alzheimer's disease is a devastating disorder with progressive dementia as its hallmark. The disease is characterised by protein plaques and nerve tangles that gradually distort the architecture of the brain. A naturally-occurring protein called amyloid has been implicated as a key player in the destructive process. Now, scientists report that a vaccine, administered nasally, may prove successful in reducing the accumulation of the debilitating amyloid plaques.

The treatment, which has previously been tested in an injection form, "creates a new avenue for treating the disease because it takes an immunological approach," lead author Dr. Howard L. Weiner of Brigham and Women's Hospital in Boston, Massachusetts, told Reuters Health.

His team's report is published in the October issue of the Annals of Neurology.

In this study using mice, the vaccine was shown to stimulate the immune system to produce antibodies that bind to the amyloid fragments and "clear them out of the brain," according to Weiner.

The investigators have so far tested the vaccine in a special strain of mice that have been bred to develop plaques similar to those seen in human Alzheimer's disease. The vaccine was able to reduce the build-up of plaques by as much as 60%, according to the researchers.

"We expect to have our nasal vaccine in clinical trials sometime next year," Weiner said.

For now, scientists are still puzzled as to why the amyloid protein accumulation occurs.

"We don't know exactly where the amyloid proteins come from, but what we do know is that the reason that they cause problems is that they get spliced in the wrong place in people with Alzheimer's disease," Weiner explained. "This causes fragments to be formed and they accumulate in the brain."

One in 10 people over age 65 and nearly half of those over 85 have Alzheimer's disease, according to the Alzheimer's Association in Chicago, Illinois. Today, 4 million Americans have Alzheimer's disease. Unless a cure or prevention is found, that number will jump to 14 million by the year 2050.

World-wide, it is estimated that 22 million individuals will develop Alzheimer's disease by the year 2025.