Mice Experiment Yields Alzheimer's Hope

It might be possible for the brain to recover from structural damage seen in Alzheimer’s disease (search). The key could be using antibodies to clear the brain of plaque (search) seen in people with this condition.

That strategy has not been tried on humans. No one knows if it would work in people, or exactly how to do it. There is currently no cure for Alzheimer’s disease, America’s leading cause of dementia. In the U.S., Alzheimer’s strikes nearly 10 percent of people older than 65 and half of those older than 85.

But researchers might be getting closer to a solution.

The hallmark of Alzheimer's disease is plaque formation in areas of the brain that control memory and thinking skills. While the cause of Alzheimer's disease remains unknown, the researchers say that evidence indicates that plaque formation and accumulation may play a role.

In a recent experiment, scientists succeeded in deleting plaque in mice with a disease similar to Alzheimer’s. The mice’s brain cells also bounced back, to some extent, from plaque damage.

The experiment was conducted by researchers including Robert Brendza, PhD, a research instructor in the neurology department at Washington University School of Medicine in St. Louis. Their findings appear in the online edition of The Journal of Clinical Investigation.

Targeting Plaque

The researchers used antibodies to clear away the plaque. The antibodies targeted a protein called Abeta (amyloid beta) (search), which is a key ingredient of the plaque seen in Alzheimer’s disease.

The antibodies were injected directly onto the mice’s brains. Afterwards, the researchers watched to see what happened next.

To peek inside the heads of the mice, the researchers put the living animals under the microscope. With a little help from fluorescent dye, the scientists could see how the brains of the mice fared.

The scientists didn’t have to wait long. The antibodies went to work quickly. After three days, plaque was sharply reduced. A “rapid reversal” was also seen in plaque-related brain injuries, say the researchers.

Exceeding Expectations

The results were better than the researchers had hoped.

Plaque can cause swelling and bumps on nerve cells, making it hard or even impossible for the cells to communicate. Brendza’s team thought they might be able to stop that from worsening.

“We thought that clearing the plaques would halt the progression of the damage -- stop the development of new swellings,” he says, in a news release. “But what we saw was much more striking: In just three days, there were 20-25 percent reductions in the number and size of the existing swellings.”

That could mean that the brain would eagerly heal if it wasn’t clogged with plaque. It’s also possible that younger animals in early stages of the disease might reap the most antibody treatment benefits, write the researchers.

They plan to keep studying the topic, the news release notes. Meanwhile, the researchers say their imaging technique could be useful for future tests.

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: Brendza, R. The Journal of Clinical Investigation, online edition. News release, Washington University School of Medicine.