Alzheimer's: An Epidemic: Diabetes, Herpes or Something Else?

Ivanhoe Broadcast News
Wednesday, May 23, 2007; 4:15 AM

PROVIDENCE, R.I. (Ivanhoe Broadcast News) -- It's been 101 years since Alzheimer's was first discovered by a German scientist. But we still don't know what causes it. Is it a virus like herpes? A type of diabetes? Or something entirely different?

The human brain stores our thoughts, controls our actions, and makes us who we are. But when Alzheimer's starts, everything stops. Plaques and tangles build up in the brain, and healthy neurons are damaged. Scientists still don't know why the plaques and tangles form, but there are theories. Suzanne de la Monte, M.D., M.P.H., a neuro-pathologist at Rhode Island Hospital and Warren Alpert Medical School at Brown University in Providence, believes Alzheimer's is actually another form of diabetes.

"We stumbled into the concept, it wasn't like we were looking for it," Dr. de la Monte says.

Her research shows the brain produces insulin just like the pancreas, and insulin levels are often lower in Alzheimer's brains.

"They had a brain form of diabetes, they had insulin resistance, and they had a loss of insulin, and that's why we dubbed the term 'type 3 diabetes.'" Dr. de la Monte says.

When researchers gave mice drugs to stop insulin from working, their brains were half the size and filled with harmful plaques. This damaged was reversed with drugs that improved insulin function, indicating therapies used to treat diabetes may also treat Alzheimer's. "I think that the evidence is there," says Dr. de la Monte.

Howard Federoff, M.D., Ph.D., a neuroscientist at Georgetown University in Washington, D.C., is studying a different idea. He believes a gene known to predict Alzheimer's may be linked to the herpes virus, which infects 70 percent of Americans and causes cold sores around the mouth.

"It could be conveyed by sharing a spoon or straw, by kissing, any type of communication that would allow active viral particles that are available in the oral cavity," Dr. Federhoff says.

In Dr. Federoff's study, the herpes virus was more active when it entered the special gene known to be a major risk factor for Alzheimer's. If further research confirms this link, patients could be put on anti-viral medication, or even be vaccinated for herpes to prevent Alzheimer's.