Cell Therapy for Acute Myocardial Infarction

In 1960, McCulloch and Till1 identified a bone marrow stem cell capable of reconstituting hematopoiesis in mice, later documenting the clonality of these cells.2 The concept of the adult stem cell thus was born.More than 3 decades later, Asahara et al3 extended this concept to include the formation of vascular elements from bone marrow–derived, circulating endothelial progenitors. Although controversial at the outset, the endothelial progenitor cell, or EPC, has now established itself within the lexicon of cardiology: At the 2005 Scientific Sessions of the American Heart Association, more than 100 abstracts contained the words “stem cell” in the title and an additional 75 contained the term EPC.4Article p 1287 The escalating interest in stem cells within cardiovascular medicine could be said to be the result of a growing body of evidence that suggests that stem cells may represent therapeutic entities. More than this, however, the concept of stem cell therapy has generated excitement by challenging the long-held paradigm that the heart cannot be repaired. In classic experiments in the laboratory of John Ross in the 1970s (Maroko et al5 and Ginks et al6), the extent of myocardial necrosis was shown to be inextricably linked to the time of coronary occlusion. These studies were not only critical in driving forward the field of reperfusion therapy but also were taken to indicate that the fate of the myocardium was irreversibly determined by this single factor.5,6 The field of cardiac stem cell therapy has reopened this question and ignited interest in the previously unthinkable notion of cardiac regeneration.Preclinical studies in a variety of animal models have provided evidence that both autologous and heterologous cells can contribute to vascular and cardiac repair after myocardial ischemia.7–16 For the purposes of this editorial, we will …