Bone marrow cell injection for chronic myocardial ischemia: the past and the future

Intramyocardial bone marrow cell injection is currently being investigated as a new therapeutic option for the treatment of chronic myocardial ischemia. Experimental studies and early phase clinical trials established a favorable safety profile of this approach and suggested that bone marrow cell injection was associated with clinical and functional improvements. Recently, a randomized, double-blind, placebo-controlled trial demonstrated that intramyocardial bone marrow cell injection was associated with beneficial effects on myocardial perfusion and anginal symptoms. However, the mechanisms by which bone marrow cells may improve myocardial perfusion are only partially understood, and several issues remain to be addressed. This review aims to provide a summary of the current experience with bone marrow cell therapy as a novel treatment option for patients with chronic myocardial ischemia. Therefore, the most frequently used cell types will be reviewed along with the mechanisms through which bone marrow cells may improve myocardial perfusion and function. In addition, possible routes of delivery are compared, and the results of currently available experimental and clinical studies are discussed.