Neural stem cells in the adult spinal cord.

Spinal cord injury results in cell loss, disruption of neural circuitry and chronic functional impairment. Several different cell types generate progeny in response to injury, which participate in scar formation and remyelination. Work over the last few years has identified neural stem cells and delineated the stem cell potential of different cell populations in the adult spinal cord under homeostasis and in response to injury. Neural stem cell properties are contained within the ependymal cell population, and these cells generate the majority of new astrocytes forming the glial scar. Oligodendrocyte progenitors give rise to myelinating oligodendrocytes in the intact spinal cord. They also generate the majority of remyelinating oligodendrocytes after spinal cord injury, with a minor contribution by ependymal cells. The fibrotic component of the scar tissue is generated by a subtype of pericytes. A better understanding of the regulation and precise function of different cells in the response to injury may aid in the development of regenerative strategies.