Mesenchymal cells in the treatment of spinal cord injury: current & future perspectives

Nearly 1.5 million people in the US live with a spinal cord injury (SCI). The cost to the healthcare system is estimated at over $10 billion annually likely because over 65% of SCIs occur at the cervical level. Despite medical advances, many SCI patients still experience substantial neurological disability and high dependency with severe loss of motor, sensory and autonomic function. The consensus from a combination of in vivo studies and in vivo models is that mesenchymal or stromal cells, and possibly even neural progenitors, regardless of derivation act through the provision of trophic support and inflammatory modulation. Indeed, they have been found to secrete a wide spectrum of diffusible factors with known roles in both. As such, mesenchymal cells, obtainable from multiple tissues, are ideally suited to addressing many pathophysiological consequences of SCI. Advances in understanding the latter, structural and functional magnetic resonance imaging, image-guided microneurosurgical techniques and transplantable cell biology have enabled the clinical use of cell-based therapies. Of the twenty most recent cell therapy clinical trials for SCI, seven involve adult bone marrow mesenchymal cells and six others umbilical cord cells. This reflects the growing recognition of the clinical potential of perinatal cells. However, a limited understanding of how best to exploit the capabilities of these cells impedes a full-scale clinical deployment. This mini-review focuses on recent developments that are likely to facilitate the targeted application of these cells to treat specific secondary pathophysiological processes.