3-D reconstruction and multiple marker analysis of mouse proepicardial endothelial cell population.
BACKGROUND
The proepicardium (PE), a transient embryonic structure crucial for the development of the epicardium and heart, contains its own population of endothelial cells (ECs). The aim of our study was to determine the pattern, anatomical orientation and phenotypic marker expression of the endothelial cell network within the PE.


RESULTS
Immunohistochemical findings revealed that proepicardial ECs express both early and late EC-specific markers such as CD31, Flk-1, Lyve-1 and Tie-2 but not SCL/Tal1, vWF, Dll4 or Notch1. Proepicardial ECs are present in the vicinity of the sinus venosus (SV) and form a continuous network of vascular sprouts/tubules connected with the SV endothelium, with Ter-119-positive erythroblasts in the vascular lumina.


CONCLUSIONS
On the basis of our results, we postulate the existence of a continuous network of ECs in the PE, exhibiting connection and/or patency with the SV and forming vessels/tubules/strands. Marker expression suggests that ECs are immature and undifferentiated, which was also confirmed with a transmission electron microscopy (TEM) analysis. Our results deliver new data for a better understanding of the nature of proepicardial ECs.
Department of Histology and Embryology, Medical University of Warsaw, Poland.
Justyna
J
Niderla-Bielińska
Student Scientific Group at the Department of Pathology, Medical University of Warsaw, Poland.
Grzegorz
G
Gula
Department of Pathology, Medical University of Warsaw, Poland.
Aleksandra
A
Flaht-Zabost
Department of Histology and Embryology, Medical University of Warsaw, Poland.
Ewa
E
Jankowska-Steifer
Department of Pathology, The Children's Memorial Health Institute, Warsaw, Poland.
Elżbieta
E
Czarnowska
Department of Histology and Embryology, Medical University of Warsaw, Poland.
Dorota M
DM
Radomska-Leśniewska
Department of Clinical Anatomy, Medical University of Warsaw, Poland.
Bogdan
B
Ciszek
Department of Pathology, Medical University of Warsaw, Poland. Electronic address: anna.ratajska@wum.edu.pl.
Anna
A
Ratajska
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism*; D005260:Female; D005865:Gestational Age; D006023:Glycoproteins / Q000378:metabolism; D021621:Imaging, Three-Dimensional; D007150:Immunohistochemistry; D008297:Male; D026901:Membrane Transport Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D046529:Microscopy, Electron, Transmission; D008955:Models, Cardiovascular; D010496:Pericardium / Q000196:embryology* / Q000378:metabolism*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D011247:Pregnancy; D042787:Receptor, TIE-2 / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism
D015415:Biomarkers; D006023:Glycoproteins; D026901:Membrane Transport Proteins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D042787:Receptor, TIE-2; D040301:Vascular Endothelial Growth Factor Receptor-2; C492273:LYVE1 protein, mouse; C079086:Tek protein, mouse
CD31; Liver bud; Lyve-1; Proepicardium; Prox1; Ter-119