Post-ischemic Neurogenesis and Brain Repair: Growth Factors and Cytokines

Stroke is the major cause of neurologic death and disability in the adult population. The persistence of neurogenesis in the adult mammalian brain has brought hope that endogenous neural progenitors may be a potential source to repair the damaged brain after cerebral ischemia. In the adult mammalian brain, neurogenesis takes place in specific regions, including the sub-ventricular zone (SVZ) of the lateral ventricle, the sub-granular zone (SGZ) of the dentate gyrus (DG) in the hippocampus and the posterior peri-ventricle (PPV) dorsal to the hippocampus. Accumulating evidence indicates that cerebral ischemia stimulates neurogenesis in adult brain. Numerous attempts in the past to better understand the complicated mechanisms of ischemia-induced neurogenesis have revealed several crucial processes such as proliferation of neural progenitors, migration and differentiation of newly-generated cells, as well as functional incorporation of these cells in the injured brain. However, the molecular mechanisms regulating these steps are far from clearly understood. This review summarizes the role of growth factors and cytokines in the regulation of neurogenesis following cerebral ischemia. The functional significance of post-ischemic neurogenesis, as well as the future research directions to achieve improved functional recovery after stroke by enhancing this endogenous process of brain repair are also discussed.

Keywords: Cerebral ischemia, neural progenitor, growth factors, cytokines, sub-ventricular zone, dentate gyrus