14 4
7.7 Cellular Approaches
There is considerable data regarding the effect of exogenous cellular transplanta-
tion in CNS injury. Cell therapies may be delivered to the spinal cord and brain by
direct injection, intrathecal infusion, polymeric microspheres, or biomaterial scaf-
folds [ 320 , 321 ]. Cell therapies primarily aim to replace damaged endogenous
cells, enhance the regeneration of endogenous tissues, and/or act as vehicles for
gene delivery and growth and neurotrophic factor delivery [ 319 , 322 , 323 ]. Neural
progenitor/stem cells (NPSCs) and mesenchymal stem cells (MSCs) , are fre-
quently utilized based on their multipotent nature and capacity to replace neuronal
lineage cells, enhance axonal regeneration, and restore interneuron communica-
tion [ 324 ]. Somatic cells and tissues such as olfactory ensheathing cells (OECs) ,
Schwann cells , fetal tissues, and peripheral nerves have been shown to be effective
in decreasing excitotoxicity via the secretion of various growth and neurotrophic
factors, producing a more favorable microenvironment for neuroregeneration
[ 324 ]. While cellular therapies show great promise, there are a number of disad-
vantages to consider such as ethical issues, tumorigenicity, and immunological
rejection [ 325 ]. These concerns vary with cell type, and as such, in this section we
will discuss the advantages, disadvantages, and relevant applications of each cell
type mentioned above in detail (see Table 7.2 ).
Table 7.2 Cell types associated with their respective effects on the CNS post-injury
A. Roussas et al.