Coronary Vessel Development

Abstract

Abstract-Development of the coronary vascular system is an interesting model in developmental biology with major implications for the clinical setting. Although coronary vessel development is a form of vasculogenesis followed by angiogenesis, this system uses several unique developmental processes not observed in the formation of other blood vessels. This review summarizes the literature that describes the development of the coronary system, highlighting the unique aspects of coronary vessel development. It should be noted that many of the basic mechanisms that govern vasculogenesis in other systems have not been analyzed in coronary vessel development. In addition, we present recent advances in the field that uncover the basic mechanisms regulating the generation of these blood vessels and identify areas in need of additional studies. A Brief Description of Coronary Vessel DevelopmentCoronary vessel development is an example of vasculogenesis followed by angiogenesis with unique variations specific to heart development. Vasculogenesis has been described as the de novo generation of blood vessels, whereas angiogenesis can be thought of as the generation of capillaries, veins, and arteries from preexisting vessels. The process begins with the delivery of vasculogenic cell types to the surface of the heart after beating has begun. These cells must then disperse throughout the heart; differentiate into endothelial cells, smooth muscle cells, pericytes, and fibroblasts; subsequently form arteries, veins, and capillaries; and finally connect to the aorta and coronary sinus. Delivery of a population of cells to an existing organ requires dynamic cellular events, and coordination of cell movement with the precise timing of delivery, commitment, and differentiation is critical for proper vessel formation and organ development. Originally, researchers thought that coronary vascular progenitors were derived from the cardiac mesoderm, like the other cell types in the myocardium and endocardium. 1,2 These data were first challenged by Manasek, 3 who demonstrated that the heart tube is initially composed of only endocardium and myocardium and that the epicardium arises from extracardiac regions. In more recent years, several studies have determined that progenitors of the epicardium and coronary vascular system are derived from extracardiac tissue, the proepicardial organ (PEO; Figure 1). Although the earliest location of these progenitors is still in debate, they appear to arise from splanchnic mesoderm. 4 -6 The PEO is associated with the septum transversum that grows from the dorsal body wall ventrally to divide the embryonic coelom into the pleuropericardial and peritoneal cavities and forms a portion of the diaphragm. 4,[7][8][9] However, the PEO is a transient structure that consists of a single epithelial layer folded into a shape resembling a grapelike cluster. In chicken (HH stage 17) and mouse (E9.5) embryos, the PEO migrates to and then over the surface of the heart to form the primitive epicardium (Figures 1 th...

Prevalence and Distribution of the Third Coronary Artery in Kenyans

“…Two orifices within the RAS had also been reported in the same setting (Saidi et al, 2002). The separate orifices for the TCA and the RCA had been explained by insufficient unification of these two vessels, during their growth towards the ascending aorta (Reese et al, 2002;Wada et al, 2003).…”

Rebuilding the Coronary Vasculature: Hedgehog as a New Candidate for Pharmacologic Revascularization

“…Morphological events that are involved in formation of the coronary vascular system have been well described, especially in avian systems (chick and quail) (Morabito et al 2002, Reese et al 2002, Wada et al 2003. Before stage 14 in the chick (embryonic day 9.5 in the mouse), the heart consists of two layers, an outer myocardial layer and an inner endocardial layer.…”

“…Vascular channel formation leads to the development of a vascular plexus that covers the heart. At later stages in development, this vascular plexus undergoes remodeling, giving rise to the mature coronary vascular system (Morabito et al 2002,Reese et al 2002,Wada et al 2003.Initial studies in avian systems have demonstrated that the proepicardial organ and the epicardium are required for coronary development because removal of either structure severely perturbs coronary vessel formation (Gittenberger-de Groot et al 2000). More recently, genetic analysis in the mouse has confirmed this observation.…”

“…Similar to other vascular systems, coronary development begins with the formation of a vascular network that is later remodeled, giving rise to the mature coronary tree (Kattan et al 2004, Morabito et al 2002 (Figure 1) Interestingly, the initial coronary vascular plexus consists of two sets of blood vessels located within different positions, the subepicardial mesenchyme and the myocardial wall (Figure 2). Morphological events that are involved in formation of the coronary vascular system have been well described, especially in avian systems (chick and quail) (Morabito et al 2002, Reese et al 2002, Wada et al 2003. Before stage 14 in the chick (embryonic day 9.5 in the mouse), the heart consists of two layers, an outer myocardial layer and an inner endocardial layer.…”

Insights Into Coronary Artery Development in Model of Maternal Protein Restriction in Mice

“…Previously, researchers believed that coronary arteries (CAs) budded from the aorta during development in humans and other mammals (Hutchins et al, 1988;Wada et al, 2003;Tomanek, 2005). However, this theory of proximal CA development is inadequate, as it does not explain the known possible congenital abnormalities of the CA (Bogers et al, 1988).…”