Cold sores bad for brain as well as looks

UK scientists have discovered that the herpes simplex virus (HSV), which is responsible for triggering cold sores, may also be linked to Alzheimer's Disease.

Professor Ruth Itzhaki and her colleagues at Manchester University found that when brain cells grown in culture were infected with the virus they dramatically increased their production of a protein called beta-amyloid 1-42.

This protein is known to accumulate, forming pathological deposits known called plaques, in the brains of Alzheimer's patients.

There are now a number of lines of evidence linking HSV infection with senile dementia and Alzheimer's. These include the discovery of viral DNA in the brain's of patients who have died of the disease, the finding that one of the viral coat proteins is very similar to the structure of beta-amyloid, which might encourage the proteins to aggregate into plaques, and a form of a gene called ApoE4 is known to be a risk factor for both Alzheimer's and herpes infection.

Itzhaki and her team now suspect that virus dormant in the brain periodically reawakens, triggering increases in beta-amyloid production and the progression of plaque formation.

But there is some good news: on the basis of their present findings, the team suggest that there are strong grounds for putting some patients on anti-herpes medication to ward off the progression of dementia.

"I think there's enough evidence to begin giving people with ApoE4 antiviral drugs to slow the progression of the disease," says Itzhaki.