Endogenous neural stem cell responses to stroke and spinal cord injury.

Stroke and spinal cord injury (SCI) are among the most frequent causes of central nervous system (CNS) dysfunction, affecting millions of people worldwide each year. The personal and financial costs for affected individuals, their families, and the broader communities are enormous. Although the mammalian CNS exhibits little spontaneous regeneration and self-repair, recent discoveries have revealed that subpopulations of glial cells in the adult forebrain subventricular zone and the spinal cord ependymal zone possess neural stem cell properties. These endogenous neural stem cells react to stroke and SCI by contributing a significant number of new neural cells to formation of the glial scar. These findings have raised hopes that new therapeutic strategies can be designed based on appropriate modulation of endogenous neural stem cell responses to CNS injury. Here, we review the responses of forebrain and spinal cord neural stem cells to stroke and SCI, the role of these responses in restricting injury-induced tissue loss, and the possibility of directing these responses to promote anatomical and functional repair of the CNS.