Microglia: Activation in acute and chronic inflammatory states and in response to cardiovascular dysfunction

Microglia are the resident immune cells in the central nervous system and are constantly monitoring their environment. After an insult, they are activated and secrete both pro- and anti-inflammatory mediators. Thus, they can have both detrimental and protective actions. Microglia are activated in many conditions that involve chronic inflammation such as Alzheimer's and Parkinson's diseases and in neuropathic pain. Following cerebral ischemia and stroke, microglia are activated and acutely contribute to neuronal loss and infarct damage. Chronically, in this condition, neuroprotective actions of activated microglia include clearance of the dead cells and secretion of neurotrophins. Of great interest is the recent observation that following myocardial infarction, there is increased inflammation within the hypothalamus and a marked increase in activated microglia.