Developmental perspectives on human midbrain-derived neural stem cells

Regeneration or restoration of lost or damaged neurons is very likely to profoundly alter the disability and needs of many patients. The replacement of dopaminergic (DA) neurons in patients with Parkinson's disease via implantation of embryonic midbrain tissue was taken from animal experiments to clinical applications. Ethical concerns related to the use of fetal tissue derived from abortions further argue for the search for alternative tissue sources. Today, it seems possible to generate functional DA neurons from a variety of stem cells, including embryonic and neural stem cells. Bone marrow stromal cells are another source for cell replacement. Neural stem cells derived from human fetal midbrain tissue maintain a considerable capacity to self-renew and to differentiate into DA neurons. Therefore, these cells may be a promising source to generate functional human DA neurons.