Bone marrow stromal cells for spinal cord repair: a challenge for contemporary neurobiology

In the last years, it has been reported that bone marrow stromal cells (BMSC) are able to differentiate towards a neuronal phenotype, in vitro as well as in vivo, and consequently, the possible use of these cells for the treatment of neurological diseases has acquired enormous importance. The objective of this review is to discuss the experimental findings that suggested the utility of BMSC for the treatment of paraplegia, and the possibilities of its clinical application in patients. For this reason, we revise our previous experimental findings about neuronal transdifferentiation of BMSC, and the utility of local BMSC transplantation in an experimental model of chronic paraplegia. Our current experience supports that a neural transdifferentiation of BMSC is possible after these mesenchymal stem cells are transplanted into injured spinal cord tissue. Furthermore, this cell therapy achieves a clear functional improvement of paraplegic animals, together with morphological evidence of spinal cord regeneration. Although at present our efforts should be guided to obtain a better knowledge of the mechanisms of nervous regeneration induced by bone-marrow derived stem cells, it is obvious that cell therapy for nervous system repair is beginning, and BMSC transplantation offers new hope for the treatment of traumatic paraplegia in humans.