Spinal cord injuries: how could cell therapy help?

Introduction: Spinal cord injury (SCI) is a devastating condition, where regenerative failure and cell loss lead to paralysis. The heterogeneous and time-sensitive pathophysiology has made it difficult to target tissue repair. Despite many medical advances, there are no effective regenerative therapies. As stem cells offer multi-targeted and environmentally responsive benefits, cell therapy is a promising treatment approach. Areas covered: This review highlights the cell therapies being investigated for SCI, including Schwann cells, olfactory ensheathing cells, mensenchymal stem/stromal cells, neural precursors, oligodendrocyte progenitors, embryonic stem cells, and induced pluripotent stem cells. Through mechanisms of cell replacement, scaffolding, trophic support and immune modulation, each approach targets unique features of SCI pathology. However, as the injury is multifaceted, it is increasingly recognized that a combinatorial approach will be necessary to treat SCI. Expert opinion: Most preclinical studies, and an increasing number of clinical trials, are finding that single cell therapies have only modest benefits after SCI. These considerations, alongside issues of therapy cost-effectiveness, need to be addressed at the bench. In addition to exploring combinatorial strategies, researchers should consider cell reproducibility and storage parameters when designing animal experiments. Equally important, clinical trials must follow strict regulatory guidelines that will enable transparency of results.