A new study recently published online in the journal Neurology of Aging stipulated that a form of the ApoE gene (a leading risk factor for Alzheimer's) known as ApoE-4 is linked to a form of herpes called herpes simplex 1 or HSV.

HSV infects more than 80 percent of Americans and causes cold sores around the mouth.

The findings from a University of Rochester Medical Center research team show that the particular form of the gene that puts people at risk of AD 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.

While the fact that ApoE-4 gene is a player in Alzheimer's disease is already known to scientists for more than 15 years, the idea that it works in connivance with the herpes virus is new.

According to Howard Federoff, M.D., Ph.D., the leader of the team and professor of Neurology, Medicine, and Microbiology & Immunology:

"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."

Ruth Itzhaki of the University of Manchester has led the way with several studies showing a correlation between herpes and Alzheimer's:

• Alzheimer's patients who have the ApoE-4 form of the gene have more herpes DNA in the brain regions that are affected by Alzheimer's, compared to Alzheimer's patients who also have herpes but who have a different form of the ApoE gene.
• people with the ApoE-4 version of the gene who are infected with herpes are more likely to get Alzheimer's disease than people infected with herpes who have a different form of the ApoE gene, or than people who have the ApoE-4 gene but who don't have herpes.

While other studies have shown that people who are frequently troubled by cold sores are more likely to have the gene that makes them more vulnerable to Alzheimer's disease.

However, Dr. Federoff concluded that, just how ApoE-4 makes people vulnerable to Alzheimer's disease isn't resolved at all in this particular study.

Find more details from the URMC press release.

[Photo Credit: Library - University of Iowa]