Microglial senescence.

In order to understand microglial senescence it is important to also understand neuroinflammation because the distinction between senescent and activated microglia is a fine one to make and not always made easily. Indeed, it is not easy to reliably identify activated microglia which is why we spend some effort here discussing intricacies associated with both acute and chronic neuroinflammation before addressing the subject of microglial senescence. The idea of microglial senescence in the context of aging-related neurodegenerative disease (NDD) pathogenesis represents a relatively recent idea that emerged largely because of the many caveats and inconsistencies found to be associated with the belief that neuroinflammation is a critical event in NDD pathogenesis. In this paper, we discuss most of these discrepancies and explain why microglial senescence can provide a better conceptual framework for understanding NDD mechanisms and for devising radically different pharmacological approaches to treatment.