Key Words

human embryonic stem cell, neural stem cell, stem cell therapy, cell replacement, regeneration, brain repair Stem cells, by virtue of their defining property of self-renewal, rep-resent an unlimited source of potentially functional human cells for basic research and regenerativemedicine.Having validated the feasi-bility of cell-based therapeutic strategies over the past decade,mostly through the use of rodent cells, the stem cell field has now embarked upon a detailed characterization of human cells. Recent progress has included improved cell culture conditions, long-term propagation, directed differentiation, and transplantation of both human embry-onic and somatic stem cells. Continued progress in understanding basic human stem cell biology, combined with a better handle on the fundamental pathophysiology of human diseases one wishes to target (including the use of human stem cells in primate and other large animal models of human disease), should help to move this technology closer to clinical application. 31