Vasculogenesis of the embryonic heart: Origin of blood island-like structures
Article first published online: 6 FEB 2006
Copyright © 2006 Wiley-Liss, Inc.
The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology
Volume 288A, Issue 3, pages 223–232, March 2006
How to Cite
Ratajska, A., Czarnowska, E., Kołodzińska, A., Kluzek, W. and Leśniak, W. (2006), Vasculogenesis of the embryonic heart: Origin of blood island-like structures. Anat. Rec., 288A: 223–232. doi: 10.1002/ar.a.20311
- Issue published online: 20 FEB 2006
- Article first published online: 6 FEB 2006
- Manuscript Accepted: 26 NOV 2005
- Manuscript Received: 14 NOV 2005
- Polish State Committee for Scientific Research
- Medical University of Warsaw. Grant Number: 6 P05A 025 20 2P05A 111 28
- murine heart;
- nucleated red blood cells
The earliest vascular structures (blood island-like) in the embryonic heart are clusters of angioblasts and nucleated red blood cells (NRBCs), which differentiate into endothelial cells and erythrocytes, respectively. Our purpose was to define the area and chronology of NRBC appearance in the mouse embryonic heart at the stages before a patency between coronary vessels and peripheral circulation is established (10.5–13.5 dpc). Before and at the onset of vascularization, NBCs were not present within the proepicardium; however, Ter/119+ differentiating erythroblasts and single scattered CD45+ were found in the heart beginning from 10.5 dpc. The Ter/119+ cells were in close apposition to angioblasts (PECAM1+) and were recognized as components of blood island-like structures or vascular vesicles in transmission electron microscope and were located mostly in the subepicardium. Some of the NRBCs were not accompanied by angioblasts and located close to the endocardial endothelium or at the border of the endocardial endothelium or in the subepicardium. These erythroblasts were beginning to assemble with angioblasts. CD34+ NBCs as well as progenitor cells of erythroid lineage were not detected in the heart at these stages of development. The state of differentiation of NRBCs of blood islands was similar/the same as the morphology of circulating blood cells at the respective stages of embryo development. The presence of mature NRBCs in the subendocardial area and lack of progenitor cells of erythroid lineage within the heart indicate that erythroid commitment occurs outside the heart. We suggest that NRBCs enter the heart from the blood stream at 10.5–12 dpc independently from angioblasts. © 2006 Wiley-Liss, Inc.