The contribution of the proepicardium to avian cardiovascular development
Published: 1 June 2001
JM Perez-Pomares, A Phelps, R Munoz-Chapuli, A Wessels
Med Univ S Carolina, Dept Cell Biol & Anat, Charleston, SC 29425 USA; Univ Malaga, Fac Ciencias, Dept Anim Biol, Malaga, Spain
The embryonic epicardial layer of the heart, which originates from the proepicardium, gives rise to a set of invasive pluripotent epicardially-derived cells (EPDCs) that contribute to the development of 1) subepicardial mesenchyme, 2) coronary vessels, 3) intermyocardial fibrous tissue, and 4) mesenchyme of the atrioventricular cardiac valve primordia. Here we report that chimeric tracing of proepicardial cells as well as a new experimental procedure reveal a non-proepicardial origin for the epicardial-like cells of the more distal part of the outflow tract of the heart (OFT). This observation is supported by the fact that the expression pattern of mesothelial antigens in the epicardial-like cells of the distal outflow tract is different from the expression pattern in the pro epicardially-derived epicardium. The delay of epicardium and EPDC development using diverse microsurgical procedures leads to abnormal cardiac phenotypes in all cardiac areas colonized by proepicardially-derived epicardium and EPDCs. These results suggest the existence of a signaling role for epicardium and EPDCs in cardiac development and support the hypothesis that ontogenetical diversity of cardiac epicardium is involved in heart chamber morphogenesis and remodeling.