Development of proximal coronary arteries in quail embryonic heart: multiple capillaries penetrating the aortic sinus fuse to form main coronary trunk

K Ando, Y Nakajima, T Yamagishi… - Circulation …, 2004 - Am Heart Assoc
K Ando, Y Nakajima, T Yamagishi, S Yamamoto, H Nakamura
Circulation Research, 2004Am Heart Assoc
Studies have shown that the proximal coronary artery (PCA) develops via endothelial
ingrowth from the peritruncal ring (PR) of the coronary vasculature. However, the details of
PCA formation remain unclear. We examined the development of PCAs in quail embryonic
hearts from 5 to 9 days of incubation (embryonic day [ED]) using double-immunostaining for
QH1 (quail endothelial marker) and smooth muscle α-actin. At 6 to 7 ED, several QH1-
positive endothelial strands from the PR penetrated the facing sinuses, and in some …
Studies have shown that the proximal coronary artery (PCA) develops via endothelial ingrowth from the peritruncal ring (PR) of the coronary vasculature. However, the details of PCA formation remain unclear. We examined the development of PCAs in quail embryonic hearts from 5 to 9 days of incubation (embryonic day [ED]) using double-immunostaining for QH1 (quail endothelial marker) and smooth muscle α-actin. At 6 to 7 ED, several QH1-positive endothelial strands from the PR penetrated the facing sinuses, and in some embryos, several endothelial strands penetrated the posterior (noncoronary) sinus. At 7 to 8 ED, the endothelial strands penetrating the facing sinuses seemed to fuse, forming a proximal coronary stem that was demarcated from the aortic wall by the nascent smooth muscle layer of the coronary artery. By 9 ED, two coronary stems were completely formed, and the endothelial strands previously penetrating the noncoronary sinus had disappeared. Confocal microscopy at 6 ED revealed discontinuous QH1-positive endothelial progenitors in the aortic wall at sites where the endothelial strands would later develop. Observations demonstrate that during the formation of the PCA, endothelial strands from the PR penetrate the facing sinuses and then fuse, whereas those strands penetrating the noncoronary sinus disappear. Thereafter, the coronary artery tunica media demarcates the definitive PCA from the aortic media.
Am Heart Assoc