Bone Marrow for the Treatment of Spinal Cord Injury: Mechanisms and Clinical Application.

Abstract

Transplantation of bone marrow stem cells into spinal cord lesions enhances axonal regeneration and promotes functional recovery in animal studies. There are two types of adult bone marrow stem cell; haematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). The mechanisms by which HSCs and MSCs might promote spinal cord repair following transplantation have been extensively investigated. The objective of this review is to discuss these mechanisms; we briefly consider the controversial topic of HSC and MSC transdifferentiation into CNS cells, but focus on the neurotrophic, tissue sparing and reparative action of MSC grafts in the context of the spinal cord injury (SCI) milieu. We then discuss some of the specific issues relating to the translation of HSC and MSC therapies for SCI patients and present a comprehensive critique of the current bone marrow cell clinical trials for the treatment of SCI to date.