• Kyodo


A research team at a state-run institute in Aichi Prefecture said Monday it has discovered a vaccine to treat and prevent Alzheimer’s disease without causing side effects.

Hideo Hara and other members of the team at Chubu National Hospital’s National Institute for Longevity Sciences in the city of Obu found the oral drug did not cause side effects in mice and was effective if administered once every six months.

Alzheimer’s is a degenerative disease of the central nervous system characterized by premature senile mental deterioration. It is caused by accumulation of excessive amounts of beta-amyloid proteins, which lead to atrophy of the brain.

In the team’s experiment, the vaccine, which is a virus whose genes have been recombined so it would artificially create beta-amyloid proteins, was fed to the mice.

As a result, an antibody produced in the mucous membranes of the intestines moved to the brain and removed the beta-amyloid proteins that had become attached to the brain, preventing them from accumulating.

The team used mice that were 45 weeks old — equivalent to humans in their 70s — and made prone to developing Alzheimer’s disease, gave them the vaccine once, and then checked their brains 11 weeks later.

Normally, accumulated beta-amyloids make up about 2.5 percent of the brain of such 56-week-old mice, but those that received the vaccine had only about 0.5 percent of their brain covered by the protein. Mice 15 weeks old, equivalent to people in their 30s, that were given the vaccine also showed almost no accumulation of the protein in their 56th week.

The team plans to test the treatment on aged monkeys by year’s end with the hope of conducting clinical tests on humans next summer.

University of Tokyo professor Yasuo Ihara said the team’s study is “significant” as the biggest issue so far in developing medical treatment for Alzheimer’s disease had been how to curb side effects of the medicine.

“From now on, the big issue will be how well to fill the gap between mice and humans in the course of clinical trials,” Ihara said.

A U.S. pharmaceutical firm developed an Alzheimer’s vaccine in 1999, involving injecting a virus under the skin, but of some 350 patients who received the treatment, 15 developed brain fever as a side effect and the vaccination program was stopped.

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