Biomedical Engineering Reference
In-Depth Information
18.3 NEURAL PROGENITOR CELLS
Neural Progenitor Cells (NPCs) are present in the adult nervous system through-
out life, can self-renew but not indefi nitely, and give rise to (differentiate into)
cells of the nervous system (neurons and glial cells) (Gage 2000; Turner et al. 1990;
Turner and Cepko 1987; Baizabal et al. 2003). (See Figure 18.1). However, in the
adult CNS, differentiation occurs in specifi c niches. Some of the locations where
NPCs are found within the adult nervous system are the olfactory bulb (Fisher
1997; Baizabal et al. 2003), hippocampus (Gage et al. 1995), sub-ventricular
zone (Palmer et al. 1997) and spinal cord (Weiss et al. 1996; Kehl et al. 1997;
Shihabuddin et al. 1997). The following section will provide additional detail
about these cells. The research performed in the author's group characterizes the
behavior of NPCs from the hippocampus of rats and humans under different
environmental conditions.
18.3.1 History of Postnatal Neurogenesis
Originally, it was thought that neurogenesis
1
in mammals only occurred in the
early developmental stages (Cajal 1913). In 1913, Santiago Ramon
y
Cajal deter-
mined that neurons were generated only before birth (Ramon
y
Cajal 1913 ).
Broad potential
self-renewing
Multipotent
stem cells
Embryo or adult
brain, blood (?)
Limited potential
limited self-renewing
Neural
progenitor
Brain or
spinal cord
?
?
Committed
neural
progenitor
Brain subregion
Limited division
non-functional
Neuronal progenitor Glial progenitor
Non-mitotic
functional
Differentiated
Specific
brain sites
Neuron
Gila
Figure 18.1.
Neural Progenitor Cells (Gage 2000), reprinted with permission from AAAS.
1. Neurogenesis: a process of generating functional neurons from progenitor cells. This process in-
cludes proliferation and neuronal fate specifi cation of neural progenitors, and maturation and func-
tional integration of neuronal progeny into neuronal circuits.
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