Post-natal Development of the Coronary Arterial Tree

University Of California-Irvine, Irvine CA

Investigators

Abstract

9978199 Kassab There is no doubt that knowledge of the adaptation mechanisms in structure and function during normal growth is important in human health. The objective of this proposal is to gain a better understanding of the adaptation mechanisms in the structure, zero-stress state and function of the coronary arteries during normal cardiac growth. The specific aims are: 1) To obtain a complete set of morphometric data on the branching pattern and vascular geometry of the coronary arterial tree during cardiac growth and to demonstrate some of the hemodynamic applications of the morphometric data; 2) To determine the changes in the stress-strain relationship of the epicardial coronary arteries during cardiac growth and development, with reference to the zero-stress state; and 3) To obtain a complete set of morphometric data of the micro-structural components of the epicardial coronary arteries during cardiac growth and to correlate the structural components to the hemodynamic and mechanical data of Specific Aims 1 and 2. The branching pattern and vascular geometry of the coronary arterial trees will be measured with the elastomer-casting method. The order number, diameter, length, and connectivity matrix will be measured for all orders of vessels of the right coronary artery, left anterior descending and left circumflex arteries. The vessel wall structural remodeling will be studied with light and electron microscopes. The changes in the volume density of arterial components, including intima, smooth muscle cells, fibroblasts, collagenous bundles, and elastic laminae will be determined. The remodeling of the zero-stress state (the state of the organ when the external loads are removed) of the epicardial coronary arteries will be determined by first cutting the arteries into short ring-shaped segments perpendicular to the longitudinal axis of the blood vessel, and then making a radial cut. This procedure causes the ring to open into a sector whose internal and external circumferential lengths will be measured and used as reference parameters at the zero-stress for the analysis of arterial mechanics. This research will lay a structural and mechanical foundations for the study of tissue engineering of the blood vessels during growth and development.