Cell therapy is a potentially useful approach to treating heart failure (HF) secondary to chronic ischemic cardiomyopathy (ischemic HF). Despite controversy, the preclinical data in the field of cell therapy are clear: Although transplanted cells do not regenerate cardiomyocytes, preclinical studies have consistently shown that they improve cardiac performance. Bone marrow–derived mesenchymal stromal cells (MSCs) are among the most promising cell types in the preclinical arena1 and for patients with ischemic HF.

The field of cell therapy is evolving rapidly. The fundamental shift has been the recognition that all cell types fail to engraft in the heart and instead work via paracrine mechanisms. This concept has 2 corollaries: (1) because transplanted cells do not persist in the heart for more than a few weeks, giving repeated doses seems logical; and (2) because cells work by releasing factors in the environment, intravenous (IV) therapy may also be effective by enabling systemic release of these factors.