Microglia in the Alzheimer's brain: a help or a hindrance?

Alzheimer’s disease (AD), the leading cause of dementia, is a complex neurodegenerative disorder. The AD brain is characterized by the presence of Amyloid-β (Aβ) plaques, neurofibrillary tangles, and an increased inflammatory response. Microglia, the chief immune cells of the central nervous system, have been implicated in AD due to their strong association with Aβ plaques. The role of inflammation associated with microglia has been hotly contested in development of Alzheimer’s disease. A growing amount of genetic studies have implicated microglia in late-onset AD and their role in Aβ clearance. Although traditionally microglia have been considered to be either in resting or activated states, these cells are now known to exist in multiple heterogeneous populations and altered roles that appear to impact pathological states of the Alzheimer’s brain