Vasculogenesis

Abstract

Induction by fibroblast growth factors of mesoderm during gastrulation leads to blood-forming tissue, including angioblasts and hemopoietic cells, that together constitute the blood islands of the yolk sac. The differentiation of angioblasts from mesoderm and the formation of primitive blood vessels from angioblasts at or near the site of their origin are the two distinct steps during the onset of vascularization that are defined as vasculogenesis. Vascular endothelial growth factor and its high-affinity receptor tyrosine kinase flk-1 represent a paracrine signaling system crucial for the differentiation of endothelial cells and the development of the vascular system. Specified cell adhesion molecules such as VE-cadherin and PECAM-1 (CD-31), and transcription factors such as ets-1, as well as mechanical forces and vascular regression and remodeling are involved in the subsequent events of endothelial cell differentiation, apoptosis, and angiogenesis.

The epicardium and epicardially derived cells (EPDCs) as cardiac stem cells

“…The use of quail-to-chick proepicardial chimeras to study proepicardial derivatives has provided some information concerning the lineage relationship between endothelial and blood cells in the subepicardial blood islands. The blood islands are often lined by quailderived (QH1-positive) endothelium, a result that is consistent with the idea that both endothelium and blood cells derive from a common hemangioblastic progenitor (Risau and Flamme, 1995;Eichmann et al, 1997).…”

“…Whereas vasculogenesis of the extraembryonic vasculature involves the formation of blood islands (vesicles with an outer mantle of differentiated endothelial cells and inner mass consisting of blood cells) (Risau and Flamme, 1995), early intraembryonic vascularization does not require their formation (Drake and Fleming, 2000). Interestingly, during early stages of cardiac development, blood islands are seen in the subepicardium (Hutchins et al, 1988;Viragh et al, 1990;Hirakow, 1992;Pérez-Pomares et al, 1997, 1998a, 1998b.…”

Differential response of normal and malignant urothelial cells to CHK1 and ATM inhibitors

“… Sustained angiogenesis: Unlike vasculogenesis which is the de novo formation of blood vessels (Risau and Flamme, 1995), angiogenesis refers to the process of new formation of blood vessels from pre-existing ones. The oxygen and nutrients carried by the vasculature are essential for cell growth and survival in both normal and malignant cells.…”

Angiogenesis induced by hepatocyte growth factor in non-infarcted myocardium and infarcted myocardium: up-regulation of essential transcription factor for angiogenesis, ets

“…[17][18][19][20] The ets family of transcription factors has a DNA-binding domain in common that binds to a core GGA(A/T) DNA sequence. 21,22 In situ hybridization studies have shown that the proto-oncogene c-ets is expressed in endothelial cells at the beginning of blood vessel formation, under normal and pathological conditions.…”