Study: Herpes Virus May Play Role in Alzheimer's Disease

A common virus that causes cold sores may play a role in the development of Alzheimer's disease, according to a study reported in the December issue of the journal Aging Cell.

Lead researcher Dr. Elaine Bearer, senior research scientist at Brown University, and her colleagues linked the herpes virus to the onset of Alzheimer's disease while studying squid.

Bearer said the discovery should trigger further study into the role the virus may play in the disease and even into possible uses of the virus in therapy.

The herpes virus was found to interact with amyloid precursor protein (APP), which breaks down to form beta-amyloid. The build-up of beta-amyloid is found consistently in the brains of Alzheimer's patients. Specifically, the researchers discovered that the virus, after coming into contact with APP moves, abnormally fast in a direction opposite its normal route.

"It's as if the virus hijacks a car and the APP is the driver," explains Bearer. "The virus takes the APP where it wants to be, not where the APP wants to be."

Although APP is found in everyone, it causes problems only in a few, according to the researchers, who noted that their discovery should not worry anyone who has ever had a cold sore.

Bearer speculated that when APP is co-opted by the herpes virus, the APP breaks down at a location where it would not normally appear and at a very different rate. "When APP piles up around neurons, the neurons die," she explains. "But we don't yet know if this is a secondary or a primary cause of Alzheimer's."

Despite their discovery, the researchers said they are uncertain whether herpes plays a causal role in Alzheimer's disease, but they noted that their findings do provide some interesting new insight into both diseases.