From bench to bedside, work in cell-based myocardial regeneration therapy

In clinical cellular cardiomyoplasty, bone marrow cells and myoblasts are introduced mainly to ischemic cardiomyopathy tissue via several cell delivery systems, such as needle injection or catheter. These clinical studies have demonstrated the safety and feasibility of this technique, but its effectiveness for treating heart failure, especially in the long term, is still under discussion. Neither of these cell types can differentiate into cardiomyocytes; rather, they improve the failing heart mainly by the paracrine effects of some cytokines, such as Hepatocyte growth factor (HGF) and Vascular endothelial growth factor (VEGF). Thus, many researchers have a great interest in stem cells, which exist in bone marrow, circulating blood, atrium, and adipose tissue, and can differentiate into cardiomyocytes. Although several stem cells with the potential to differentiate into various cell types have been reported, few can differentiate into cardiomyocytes. Moreover, beating cells that can demonstrate synchronized contraction with native cardiomyocytes are critical for the complete repair of severe heart failure. Therefore, stem cells with a high differentiation capacity should be explored for the goal of completely repairing severely damaged myocardium. In this review, we summarize the clinical protocols and basic experiments for cellular cardiomyoplasty using bone marrow cells, myoblasts, and other stem cells.