Translational challenge for bone marrow stroma cell therapy after stroke.

There is increasing evidence that the transplanted bone marrow stromal cells (BMSC) significantly promote functional recovery after central nervous system (CNS) damage in the animal models of various kinds of CNS disorders, including cerebral infarct. However, there remain several challenges before considering BMSC transplantation for patients with ischemic stroke. In this review, therefore, the authors discuss what should be clarified to establish cell transplantation therapy in the clinical setting and describe their scientific contributions in this matter. The BMSC have the ability to alter their gene expression profile and phenotype in response to the surrounding environment and to protect the neurons by producing certain neurotrophic factors. They also promote neurite extension and rebuild the neural circuits in the injured CNS. The BMSC can be expanded in vitro using the animal serum-free medium. Pharmacological modulation may accelerate the in vitro proliferation of the BMSC. Using in vivo optical imaging technique and MRI, the transplanted BMSC can noninvasively be tracked in the living animal for at least 8 weeks after transplantation. It is urgent to develop a clinical imaging technique to track the transplanted cells in the CNS and evaluate the therapeutic significance of BMSC transplantation in order to establish it as a definite therapeutic strategy in the clinical setting in the future.