Cell therapy to repair injured spinal cords: olfactory ensheathing glia transplantation.

The absence of spontaneous axonal regeneration in the adult mammalian central nervous system cause devastating functional consequences in patients with spinal cord injuries. During the past decades several attempts have been made in order to find a strategy to repair injured spinal cords in experimental animals, that could provide a novel therapeutic approach in humans. Cell transplantation has been broadly used as an intervention to influence neuronal survival and axonal regeneration in the severed neuraxis. Of the cell types used for transplantation, olfactory ensheathing glia (OEG) promoted a dramatic functional improvement and anatomical repair after complete transection of the adult mammalian spinal cord. These cells can be easily obtained from adult donors opening the possibility of autologous transplantation. Grafting OEG to repair injured spinal cords offers some advantages compared to injections of other cell types. Therefore, OEG have become good candidates to bring about repair in damaged spinal cords. In this article we review OEG transplantation studies, discuss the properties that could account for their axonal growth-promoting ability, and the advantages of using OEG as a repair strategy.