Medicina Molecular e Genética

Emerging Links between Herpesviruses and Alzheimer's Disease Pathology

Abstract

Sasmita AO, Methi A and Kislai P

Over 3.7 billion people worldwide under the age of 50 are estimated to have some form of Herpes simplex virus (HSV) infection in their lifetime. Despite mostly presenting as asymptomatic, HSV infection has been associated with worsening symptoms and biological conditions in various diseases, some of which are neurological, such as Alzheimer’s disease (AD). This mini-review thus aims to showcase the varying researches carried out in the past decades which sought the connection between the infection and the neurodegenerative disease. Various members of the Herpes viridae family have been associated with worsening AD pathology and symptoms, namely HSV-1, HSV-2, human herpes virus 6 (HHV-6), and HHV-7. The virus affects many aspects of the nervous system to promote neurodegeneration, including fragmentation of amyloid precursor proteins (APP), inducing production of excess amyloid beta (Aβ) in response to the viral infection, and formation of tau neurofibrillary tangles (NFT), all of which point to further degeneration of the nervous system structures and cognitive decline in AD patients. HSV has been significantly reported to induce concurrent alterations in the context of AD. Although more in-depth analysis still needs to be done to consider other factors such as age, viral load, and the degree of neurodegeneration, HSV infection remains an interesting drug target through the means of antivirals in ameliorating a certain degree of neurodegeneration, cognitive decline, and memory loss in AD.