The Adult Epicardium

From the first description of its origins by the Polish-German anatomist Robert Remak in 1855, through to latter day studies into its role in establishing the coronary vasculature (reviewed in1), the embryological epicardium (outermost mesothelial epithelial layer that envelops the developing heart) has intrigued embryologists, cell biologists, and cardiologists alike. The adult epicardium, on the other hand, has been consigned to the overall view that the mature mammalian heart is a terminally differentiated postmitotic organ in which the major structural cell types survive a life time without support from either new vascular or myocardial cells. However, recently the quiescent nature of the adult epicardium has been contested. After appropriate stimulation (by the actin monomer binding protein Thymosin β4) adult epicardium-derived cells (EPDCs) were shown to have the capacity to proliferate, migrate, and differentiate ex vivo into vascular …