Alzheimer's disease may be caused by a virus
Herpes simplex virus type 1 causes cold sores
and maybe Alzheimer's disease
A team of researchers headed by Professor Ruth Itzhaki from the Faculty of Life Sciences at the University of Manchester, UK has found localization of herpes simplex virus type 1 (HSV1) DNA within the amyloid plaques present in the brains of Alzheimer's disease patients.[1] In Alzheimer's disease brains, 90% of the plaques contained the viral DNA and 72% of the DNA was associated with plaques; in aged normal brains, which contain amyloid plaques at a lower frequency, 80% of plaques contained herpes simplex virus type 1 DNA but only 24% of the viral DNA was plaque-associated.
The researchers think that the strong association of herpes simplex virus type 1 DNA within the amyloid plaques makes the virus a very likely causative agent of Alzheimer's disease, particularly because most people harbor the virus. Other experiments using antiviral agents such as acyclovir for treating Alzheimer's disease have shown a reduction of amyloid plaque deposition. Professor Itzhaki said:
We suggest that HSV1 enters the brain in the elderly as their immune systems decline and then establishes a dormant infection from which it is repeatedly activated by events such as stress, immunosuppression, and various infections. The ensuing active HSV1 infection causes severe damage in brain cells, most of which die and then disintegrate, thereby releasing amyloid aggregates which develop into amyloid plaques after other components of dying cells are deposited on them.
The researchers hope that clinical trials will be set up to test the effect of antiviral agents on Alzheimer's disease patients.
[1] Wozniak M, Mee A, Itzhaki R., Herpes simplex virus type 1 DNA is located within Alzheimer's disease amyloid plaques, J Pathol. 2008 Sep 18. PMID: 18973185
© Copyright - Antonio Zamora
