Neurons, Stem Cells and Potential Therapies

Abstract

Contrary to long held theory it has been shown recently that there are self-renewing stem cells in the adult central nervous system and that neuronal precursor cells can be derived in vitro from embryonic stem (ES) cells as well as other types of adult stem cells. Differentiation can be controlled by growth factors and culture conditions, such as, epidermal growth factor for the astrocyte lineage, and basic fibroblast growth factor for neuronal phenotypes, presumably by selection of stem cells with different potentials. Cell lines derived from different stages of neuronal development may provide cell sources with more directed potential to different types of neuronal cells. For example, lines restricted to glial differentiation may be useful therapeutically for transplantation for remyelination and other cell lines for replacement of lost neurons. On the other hand, adult neural stem cells appear to have multi—cell type plasticity and can give rise to progeny of many different tissue cell types, and ES cells can give rise to different types of neuronal cells. ES cells show great promise for replacement of injured nerve tissues, but technical and ethical problems need to be resolved.