Cellular and Molecular Approaches to Regeneration and Repair

Abstract

As cell-based therapies have demonstrated efficacy in the treatment of experimental and clinical stroke, their mechanisms of action warrant intense investi- gation and are being investigated in greater depth. It is becoming increasingly clear that one of the main ways that cell therapies based on mesenchymal stem cells (MSC) and other cells impart functional benefits to animals is through release of exosomes and other extracellular vesicles in vivo. Mounting evidence shows that MSCs release exosomes, and that these exosomes induce predictable and impactful changes in recipient cells. These exosome-induced cellular changes are likely mediated through the content of the exosomes, which comprise mRNA, miRNA, proteins, and other macromolecules. Many studies that have been published in the last several years have shown that treatment of animals with exosomes, harvested from MSCs and other cells, after stroke and traumatic brain injury (TBI) recapitulate the effect of the parent cells. Exosomes lack the safety and manufacturability issues that plague cell therapy, and they therefore may represent the next generation of cell-free therapies. Their biology and potential use as therapies for CNS injuries are discussed herein. Keywords