RESUMEN
Cell transplantation for spinal cord injury (SCI) has largely been studied in sub-acute settings within 1-2 weeks of injury. In contrast, here we transplanted skin-derived precursors differentiated into Schwann cells (SKP-SCs) into the contused rat spinal cord 8 weeks post-injury (wpi). Twenty-one weeks later (29 wpi), SKP-SCs were found to have survived transplantation, integrated with host tissue, and mitigated the formation of a dense glial scar. Furthermore, transplanted SKP-SCs filled much of the lesion sites and greatly enhanced the presence of endogenous SCs, which myelinated thousands of sprouting/spared host axons in and around the injury site. In addition, SKP-SC transplantation improved locomotor outcomes and decreased pathological thickening of bladder wall. To date, functional improvements have very rarely been observed with cell transplantation beyond the sub-acute stage of injury. Hence, these findings indicate that skin-derived SCs are a promising candidate cell type for the treatment of chronic SCI.