A gene known to be a major risk factor for Alzheimer’s disease puts out the welcome mat for the virus that causes cold sores, allowing the virus to be more active in the brain compared to other forms of the gene. The new findings, published online in the journal Neurobiology of Aging, add some scientific heft to the idea, long suspected by some scientists, that herpes somehow plays a role in bringing about Alzheimer’s disease.
The work links a form of the ApoE gene known as ApoE-4, which after advanced age is the leading known risk factor for getting Alzheimer’s disease, with the form of herpes ? herpes simplex 1 or HSV ? that infects more than 80 percent of Americans and causes cold sores around the mouth. The findings from a group at the University of Rochester Medical Center show that the particular form of the gene that puts people at risk also creates a fertile environment for herpes in the brain, allowing the virus to be more active than other forms of the ApoE gene permit.
Scientists have known for more than 15 years that the ApoE-4 gene is a player in Alzheimer’s disease, but the idea that it works in concert with the herpes virus is new.
“This work raises the question whether herpes in concert with ApoE-4 increases the risk of Alzheimer’s disease. The data suggests that ApoE-4 may support the ability of HSV to be a more virulent pathogen,” said Howard Federoff, M.D., Ph.D., the leader of the team and professor of Neurology, Medicine, and Microbiology & Immunology. He worked closely with post-doctoral research associate Renee Miller, Ph.D., on the project.
The findings, which are based on measurements of the activity levels of the herpes virus in the brains of mice with different forms of the human ApoE gene, bring together several lines of research that have pointed toward a possible role for herpes in Alzheimer’s disease.