Immunolocalization of the vascular endothelial growth factor receptor-2 inthe subepicardial mesenchyme of hamster embryos: identification of the coronary vessel precursors
Jm. Perez-pomares et al., Immunolocalization of the vascular endothelial growth factor receptor-2 inthe subepicardial mesenchyme of hamster embryos: identification of the coronary vessel precursors, HISTOCHEM J, 30(9), 1998, pp. 627-634
The earliest evidence of the development of the cardiac vessels in mammals
is the emergence of subepicardial blood islands, which are thought to origi
nate from mesenchymal progenitors. In order to identify these progenitor ce
lls, we have studied the immunohistochemical localization in the heart of S
yrian hamster embryos of the type 2 vascular endothelial growth factor rece
ptor, the earliest molecule known to be expressed in the vasculogenic cell
lineage. Only a few immunoreactive subepicardial mesenchymal cells were pre
sent by 10 days post coitum. By 11 days post coitum, the subepicardial mese
nchymal cells became abundant at the dorsal part of the ventricle, the atri
oventricular and the conoventricular grooves. About 20% of cells were label
led with the antibody. Immunoreactive cells were isolated or formed pairs,
short cords, rounded clusters or ring-like structures at the subepicardium
or, occasionally, within the ventricular myocardium. Other labelled cells w
ere simultaneously cytokeratin immunoreactive. By 12 days post coitum, most
immunoreactive mesenchymal cells have been replaced by a capillary network
. We propose that an active process of vascular differentiation occurs betw
een 10 and 12 days post coitum in the subepicardium of this species, and it
might be a suitable model for the study of vasculogenetic mechanisms. (C)
1998 Chapman & Hall.