Midbrain-derived neural stem cells: from basic science to therapeutic approaches.

Neural stem cells (NSCs) are a subtype of tissue-specific progenitor cells capable of extended self-renewal and the ability to generate all major cell types of nervous tissue, such as neurons, astroglia and oligodendroglial cells. Recent studies suggest that salient patterning in anterior-posterior and dorsal-ventral axes occurs early, concomitantly with neural induction and therefore stem cells and restricted precursors exhibit regionalization. Fetal mesencephalic NSCs can be isolated and expanded in vitro for many months while retaining their potential to differentiate into glia and neurons, with a subset of neurons displaying all the major properties of mature functional dopaminergic neurons. Since Parkinson's disease (PD) is characterized by the loss of a specific type of dopaminergic cells, the prospect of replacing the missing or damaged cells is very attractive in PD. Thus, mesencephalic NSCs might serve as a new and continuous source of dopaminergic neurons for regenerative strategies in this neurodegenerative disorder. This review discusses new data concerning the cell biology and therapeutic potential of NSCs derived from the midbrain region of the central nervous system.