Transplantation of umbilical cord blood stem cells for treating spinal cord injury.

Spinal cord injury (SCI) develops primary and secondary damage to neural tissue and this often results in permanent disability of the motor and sensory functions. However, there is currently no effective treatment except methylprednisolone, and the use of methylprednisolone has also been questioned due to its moderate efficacy and the drug's downside. Regenerative medicine has remarkably developed since the discovery of stem cells, and many studies have suggested the potential of cell-based therapies for neural injury. Especially, the therapeutic potential of human umbilical cord blood cells (hUCB cells) for intractable neurological disorders has been demonstrated using in vitro and vivo models. The hUCB cells are immune naïve and they are able to differentiate into other phenotypes, including the neural lineage. Their ability to produce several neurotropic factors and to modulate immune and inflammatory reactions has also been noted. Recent evidence has emerged suggesting alternative pathways of graft-mediated neural repair that involve neurotrophic effects. These effects are caused by the release of various growth factors that promote cell survival, angiogenesis and anti-inflammation, and this is all aside from a cell replacement mechanism. In this review, we present the recent findings on the stemness properties and the therapeutic potential of hUCB as a safe, feasible and effective cellular source for transplantation in SCI. These multifaceted protective and restorative effects from hUCB grafts may be interdependent and they act in harmony to promote therapeutic benefits for SCI. Nevertheless, clinical studies with hUCB are still rare because of the concerns about safety and efficiency. Among these concerns, the major histocompatibility in allogeneic transplantation is an important issue to be addressed in future clinical trials for treating SCI.