Common Viruses May Be Triggering Alzheimer’s Disease
Varicella zoster virus (VZV), which commonly causes chickenpox and shingles, activates herpes simplex virus (HSV) from dormancy in neural tissue grown in vitro, which then leads to an increase in plaque deposits and decrease in neural signaling — hallmarks of Alzheimer’s disease. Credit: Tufts University
Shingles infection may awaken dormant neurological herpes viruses, causing inflammation and accumulation of Tufts University and the University of Oxford.
Normally HSV-1 – one of the main variants of the herpes simplex virus — lies dormant within the neurons of the brain. However, when it is activated it leads to the accumulation of tau and amyloid beta proteins and loss of neuronal function. These are signature elements found in patients with Alzheimer’s disease.
“Our results suggest one pathway to Alzheimer’s disease, caused by a VZV infection which creates inflammatory triggers that awaken HSV in the brain,” said Dana Cairns, GBS12, a research associate in the Tufts University Biomedical Engineering Department. “While we demonstrated a link between VZV and HSV-1 activation, it’s possible that other inflammatory events in the brain could also awaken HSV-1 and lead to Alzheimer’s disease.”
The study was published recently in the Journal of Alzheimer’s Disease.
Viruses Lying in Wait
“We have been working off a lot of established evidence that HSV has been linked to increased risk of Alzheimer’s disease in patients,” said David Kaplan, Stern Family Professor of Engineering and chair of the Department of Biomedical Engineering at Tufts’ School of Engineering. One of the first to hypothesize a connection between herpes virus and Alzheimer’s disease is Ruth Itzhaki of the Common Viruses May Be Triggering Alzheimer’s Disease