Developmental and Potential Therapeutic Aspects of Mammalian Neural Stem Cells

Abstract

Advances in our understanding of the biology of stem cells, including neural, hematopoietic and mesenchymal stem cells, have opened new avenues for cell-based therapeutic approaches to replace damaged or lost neurons. The mature central nervous system (CNS) has traditionally been considered an unfavourable environment for the regeneration of damaged axons or the generation of new neurons. The recent realization that neural stem cells exist not only in the developing mammalian nervous system but also in the adult CNS of most mammals—including humans—raises the possibility of using either endogenous or transplanted neural stem cells for therapy. Although the location of neural stem cells in the adult CNS is relatively restricted, the restorative potential of stem cells is enhanced by their ability to migrate throughout the CNS. Many aspects of the biology of neural stem cells, including migrational control, proliferative, and differentiative cues are still poorly understood. In order to effectively utilize neural stem cells, either after transplantation or by promoting the mobilization of endogenous cells, will require the ability to manipulate the molecular cues that mediate commitment to particular cell lineages and their differentiation to functional cell types within the settings of neural injury or disease. If neural stem cells can be guided to replace lost neuronal or glial cell populations in the damaged adult CNS, they may offer a highly effective therapy for a wide range of degenerative diseases and insults to the adult human nervous system.