Toward Development of in-situ Endothelialized Artificial Graft : Hydrodynamic Shear Stress Dependent Retention of Endothelial Cells Adhered to a Vascular Endothelial Growth Factor-Fixed Surface

点击翻译按钮获取中文摘要

The full endothelialization of the luminal surface of an implanted small-diameter artificial graft is a requirement for expressing nonthrombogenic potential. Our strategic approach to meet that requirement is in-situ harvesting of circulating endothelial progenitor cells (EPCs) on a luminal surface of an implanted graft. The first phase of this research emphasized the determination of an appropriate receptor-counter-receptor pair, thereby enabling the clonal adhesion of EPC and high cell retention under flow loading. The radial flow chamber, installed with a three-regiospecific-protein-fixed substrate (fibronectin for integrin, and VEGF and anti-Flk-1 antibodies for VEGF receptor), clearly differentiated shear-stress-dependent cell retention potential of endothelial cells (ECs; ECs were used here as a cell model closed to EPCs because of difficulty in harvesting EPCs), which depends on the type of fixed protein and cell adhesion period. High shear-stress-resistance potential was in the order of fibronectin > VEGF and anti-Flk-1 antibody. The adhesion potential from the cell adhesion area and cell shape were both determined from phase-contrast microscopic and scanning electron microscopic images. The distribution and magnitude of fluorescence intensity of fluorescently immunostained vinculin (a key protein of focal adhesion plaque) were determined using total internal reflection fluorescence microscopy. All indicated that round cells were much more easily detachable than well-spread shaped cells. A potential in-situ EPC harvest technology is discussed in this paper.