Till truth makes all things plain: human hearts and stem cells.

Abstract

All humans develop from stem cells. Each of us also has a “rescue” system of stem cells circulating in the blood and residing in our heart (and other organs) that is intended to repair injuries. However, early after birth, the heart’s ability to regenerate itself becomes impaired.1 Improving our understanding of stem cells and building on the capabilities of this system may ultimately enable researchers to use cell therapy not only to repair injuries locally but also to regenerate the whole heart and other organs. Although preclinical studies provide valuable information, proof of the safety and efficacy of stem cell therapy has and will continue to come from studies in humans with cardiovascular diseases—the best model for this work. Thus, we should perform our human research of stem cell therapies as Shakespeare urged, “till truth makes all things plain” (A Midsummer Night’s Dream, Act V, sc. 1, line 128). Multiple small-scale clinical studies examining the use of various types of cells for treating patients with cardiovascular diseases have shown that the therapy is safe and may provide clinical benefits.2–8 In patients with ischemic heart disease, transendocardial injections of autologous bone marrow–derived mononuclear cells,5 bone marrow–derived aldehyde dehydrogenase–bright stem cells,8 or adipose tissue–derived mesenchymal cells (PRECISE)6 have been shown to be safe. Moreover, the results of these studies have revealed that these cell types may improve myocardial function, including perfusion and contractility. In addition, intracoronary infusion of autologous c-kit+ cardiac stem cells in patients with severe coronary artery disease who underwent coronary bypass surgery was shown to be safe and to improve left ventricular (LV) function and reduce infarct scar size (SCIPIO).2 Similarly, intracoronary infusion of cardiosphere-derived cells (a mixture of resident cardiac stem cells) obtained from endomyocardial biopsy …