Emerging Role of Stem Cells - Derived Exosomes as Valuable Tools for Cardiovascular Therapy

In modern society, myocardial infarction is a major cause of mortality, morbidity and deterioration of quality of life. Although various therapeutic approaches are available, none of them lead to the regeneration of infarcted tissue. The use of mesenchymal stem cells in cell therapy for myocardial infarction showed a beneficial effect consisting in reduced infarcted area and improved cardiac function, which can be explained by paracrine mechanism. It has been shown that stem cells are able to release a very complex range of factors including growth factors, cytokines and chemokines, along with an abundant mixture of membrane vesicles. These secreted elements contribute to the beneficial effect of stem cells therapy observed both in vitro and in vivo. Recent studies have shown that exosomes, which are small membrane vesicles originating in the endocytic pathway of the cells and carry a complex cargo consisting in mRNA, microRNA and various other anti-apoptotic and pro-angiogenic factors, are the main mediators of stem cells paracrine effect. In this review, we discuss the capacity of mesenchymal stem cells to protect the ischemic myocardium, the role of exosomes as protective factors secreted by stem cells and the possibility to use these vesicles in developing a novel approach in cardiovascular therapy, involving a non-cellular use of mesenchymal stem cells paracrine activity.