Endocardial Flowers: A Bouquet of Arterial Endothelial Cells Generated From New and Pre-Existing Endothelial Cells Within the Endocardium of Infarcted Heart

Ischemic heart disease is the major underlying cause of myocardial infarction (MI), scarring, and hypertrophy that can progress to heart failure. Each year, ≈300 000 individuals have recurring MIs, which is projected to ≈40% of the US population in the next 15 years. More recently, angiogenic therapy for myocardial ischemia has received significant attention. These therapeutic angiogenic strategies include gene therapy, delivery of growth factor proteins, and stem cell implantation. Although these approaches are attractive, there are limitations and concerns, including delivery modalities, uncontrolled angiogenesis, limited half-life of growth factors, and off-target effects on other organs. Moreover, limited success of therapeutic angiogenesis in myocardial revascularization left us with more questions than answers. Is the damaged heart capable of inducing new vessel growth? If so, what is the source of coronary vessel growth? What are the molecular mechanisms involved? Fortunately, recent studies on coronary vascular development have begun to answer these questions.