Stem Cell Extracellular Vesicles: A Novel Cell-Based Therapy for Cardiovascular Diseases

Cell-based therapies for ischemic heart disease have gained immense popularity in the recent past. Although the mechanisms through which transplanted cells exert beneficial effects remain incompletely understood, "paracrine effects" seem to play an important role in cell-mediated cardiovascular repair. Recent evidence indicates that in addition to numerous soluble factors, stem cells also release extracellular vesicles (EVs), which represent minute, membrane-bound cytoplasmic fragments that are either shed from the cell surface (microvesicles) or secreted from the endosomal compartment (exosomes). Stem cell-derived EVs have been shown to contain cell-specific mRNAs, microRNAs, proteins, and lipids; and to alter the gene expression, proliferation, and differentiation of target cells via transferring these bioactive contents from donor cells. Since EVs may carry several biological properties of the parent stem cells, it is likely that paracrine benefits of cell therapy are effected, at least in part, by EVs. Thus, EV-based therapeutic approaches may potentially circumvent the vagaries of whole cell administration in the future. This chapter focuses on stem cell-derived EVs as important intercellular messengers participating in cardiovascular repair.