Cultures of Stem Cells of the Central Nervous System

Over the past few years, the view that little or no cell turnover or replacement takes place within the adult central nervous system (CNS) has changed dramatically. The adult brain of both rodents and primates has been shown to embody undifferentiated, mitotically active precursor cells that are multipotential in nature and may contribute new, differentiated neurons and glia to specific regions of the mature brain, such as the olfactory bulb (Hinds, 1968a ,Hinds, 1968b ; Bayer, 1983 ; Corotto et al., 1993 ; Lois and Alvarez-Buylla, 1994 ), the hippocampus (Altman and Das, 1965 ; Kaplan and Bell, 1984 ; Kuhn et al., 1996 ) and the cortex (Kaplan, 1981 ; Huang and Lim, 1990 ; Gould, et al., 1999 ). Although this clearly suggests the presence of stem cells in the adult CNS in vivo, testing the proliferation, self-renewal, and differentiation capacity of “putative” CNS stem cells relies on the development of methodologies that allow for their extensive propagation and expansion in vitro.