How can viruses influence the neuroinflammation and neurodegeneration in the aged human brain.

Abstract

Age is one of the key risk factors of several human neurodegenerative disorders such as Alzheimer΄s disease and Parkinson΄s disease. During aging the immune system of the brain undergoes multiple structural and functional changes. The major immune cells of the brain - microglia and astrocytes - significantly change their morphology and functional state during aging. Similarly, the blood brain barrier (BBB), that is considered to be the iron curtain protecting the brain parenchyma against invasion of the pathogens, can be influenced by aging. This state of altered brain immunity may lead to the increased brain vulnerability to viral infections, primoinfection as well as reactivation. We hypothesize that impairment of the brain immunity and BBB integrity can create the optimal condition for viral infection that can further amplify the neuroinflammation mediated by glial cells and neurodegeneration induced and driven by disease modified proteins.