Cell Grafting for Spinal Cord Injury Repair: Cell Replacement and Bridging Strategies

Recent progress in the development of novel treatments for neurological injury and disease in experimental models has made the clinical success of therapies for spinal cord injury (SCI) repair seem plausible. Transplantation of a heterogeneous population of peripheral and central nervous system, epithelial, immune, and undifferentiated stem or restricted precursor cells has been effective in SCI repair. Cell grafts from these disparate sources have been shown to reduce progressive tissue loss, retard axonal dieback, promote sensory, proprio-, and/or supraspinal axon regeneration, facilitate myelination, and improve functional outcome in experimental models of SCI. Cellular therapies for SCI repair can be classified into three broad categories: cells endogenous to the organism that can be modified or recruited in vivo; cells endogenous to the organism that can be harvested, purified, and/or altered ex vivo and can subsequently be autologously implanted; and cells that can be harvested from one organism, purified and/or modified ex vivo, and transplanted into the injured organism as in allograft or xenograft.