Over the last decade, neural stem cell research has provided penetrating insights into the plasticity and regenerative potential of the brain. Stem cells have been isolated from embryonic as well as adult central nervous system (CNS). Many non-CNS mammalian tissues also contain stem cells with a more limited repertoire: the replacement of tissue-specific cells throughout the li- time of the organism. Progress has been made in understanding fundamental stem cell properties that depend on the interplay of extrinsic signaling factors with intrinsic genetic programs within critical time frames. With this growing knowledge, scientists have been able to change a neural stem cell’s fate. - der certain conditions, neural stem cells have been induced to differentiate into cells outside the expected neural lineage and conversely, stem cells from nonneural tissue have been shown to transdifferentiate into cells with distinct neural phenotypes. At the moment, there is an accelerated effort to identify a readily ava- able, socially acceptable stem cell that can be induced to proliferate in an und- ferentiated state and that can be manipulated at will to generate diverse cells types. We are on the threshold of a great new therapeutic era of cellular therapy that has as great, if not greater, potential as the current pharmacologic era, g- rified by antibiotics, anesthetics, pain killers, immunosuppressants, and psyc- tropics.
