March 28, 2016
- Department of Pathology
Dr. Bearer's work on transport has made significant discoveries on Alzheimer's dementia, including the controversial opinion that microbes that travel inside neurons may play a role. This opinion was dramatically presented last week (March 18, 2016) in Journal of Alzheimer's Research by a consortium of over 30 investigators from 7 different countries. Scientific American picked up the idea and posted a thoughtful commentary on this controversial opinion, showing support for the idea and for further research on microbial affects on the brain from investigators at Harvard, Stanford, and Washington University in St. Louis. While over 100 scientific publications defend the possibility and describe evidence of links between microbes and Alzheimer's many scientists remained unconvinced, an opinion based on three publications. The infections linked to Alzheimer's Disease are commonly acquired in childhood. Clearly the degree of controversy demands that the topic be studied further, especially since infectious etiologies are often treatable whereas to date, after billions of dollars spent on finding a cure, no treatment for Alzheimer's disease has yet been found.
Microbes and Alzheimer's Disease. Itzhaki RF, Lathe R, Balin BJ, Ball MJ, Bearer EL, Braak H, Bullido MJ, Carter C, Clerici M, Cosby SL, Del Tredici K, Field H, Fulop T, Grassi C, Griffin WS, Haas J, Hudson AP, Kamer AR, Kell DB, Licastro F, Letenneur L, Lövheim H, Mancuso R, Miklossy J, Otth C, Palamara AT, Perry G, Preston C, Pretorius E, Strandberg T, Tabet N, Taylor-Robinson SD, Whittum-Hudson JA. J Alzheimers Dis. 2016 Mar 8. [Epub ahead of print] No abstract available. PMID: 26967229
Read commentary on Microbes and Alzheimer's from Scientific American
HSV gets into the brain, here's how we think it works: Virus infects the lip and makes a cold sore. By breaking through the skin, it gets into neurons and travels up their long processes into the brain. Many other viruses also do this, like polio and rabies. HSV is composed of four concentric compartments, each of which play their part in this nasty business. When HSV enters a neuron it can live forever, sleeping near the nucleus. When HSV re-awakens, it does more damage, traveling back the way it came.
Inside cells, HSV reproduces, make many many tiny viral particles. These babies have a problem--how to get out of the cell and into another cell to promote the infection. The Bearer lab has discovered that this birth involves a dance between the virus and the cellular protein, APP. APP is the protein that makes the plaques that clog the brain in Alzheimer's disease. Thus we suspect that re-awakened virus in the brain can mess up APP and precipitate plaques, leading to Alzheimer's or other brain damage.