Where do you come from and what are you going to become, reactive astrocyte?

Astrocytes are fascinating resident cells of the central nervous system (CNS). They overcome neurons in number, and they were long believed to play a mere structural and homeostatic function in the healthy brain and spinal cord. This shortsighted view has now profoundly changed and astrocytes are universally recognized as one of the major players in the response of brain tissue to pathological conditions. In particular, following an acute brain injury (such as stroke or stab wound) but also in chronic degenerative pathologies, astrocytes leave their quiescent state and become activated (1). Reactive astrocytes undergo significant and substantial changes, in fact they: (I) become hypertrophic; (II) up-regulate intermediate filaments [composed of nestin, vimentin and glial fibrillary acidic protein (GFAP)]; (III) activate cell proliferation; and (IV) migrate to the site of injury to form the so-called “glial scar” (1).