Although the sample size in work of Bartolucci et al. was small (15 controls and 15 HF patients treated with UC-MSCs) to establish either safety or efficacy, the echocardiographic and cardiac MRI evaluations demonstrated improvements in ejection fraction, starting at 3 months, and persisting through 12 months. The patients treated with placebo did not improve in either left ventricular ejection fraction or clinical functional class. As indicated by the authors, it is tempting to speculate that the robust paracrine secretion of various factors, including hepatocyte growth factor, might play an important role in mediating the therapeutic effects of the UC-MSCs. A cell-based therapy could offer additional clinical benefits for post-ischemic heart by improving revascularization along with structural and functional properties.