Translating stem cell therapies to the clinic

Abstract

One of the most remarkable advances in translational neuroscience of the last few years has been the emergence of cell-based approaches for a wide range of neurological disease and injuries. Molecular approaches designed for the treatment of neurological injuries and insults such as stroke, spinal cord injury and multiple sclerosis have proven to be of limited effectiveness in large part because it has become clear that there is not a single "magic bullet" that allows for neuronal survival, axonal regeneration and/or remyelination. Rather the pathogenesis of insults such as stroke, spinal cord injury and MS are complex, engaging multiple cell types and signaling pathways and as a result require the simultaneous intervention in multiple arenas in order to facilitate functional recovery. Cell therapies, because of their inherent complexity offer the opportunity to intervene at several points in the pathological process and thus may provide a more effective treatment strategy. Among the multiple cell types assessed as therapeutic treatment for neural insults, stem cells have emerged as possibly the most effective class. The particular characteristics of stem cells, namely their ability to self-renew and generate multiple cell types promoted their use as sources of cell replacement in the injured CNS. It is likely, however that the major advance that stem cells have over more restricted cell types is their ability to modulate the responses of the immune system and to influence endogenous tissue stem cells to accentuate repair. While preclinical studies are moving extremely rapidly, the effective translation of these studies to the clinical arena remains extremely challenging.