Abstract 276: Tissue Engineering a Small Diameter Vascular Graft

Abstract

Introduction The patency rate of synthetic small diameter grafts for coronary and peripheral arterial bypass remains poor. The aim of this study was to engineer an acellular, biocompatible conduit with biomechanical properties similar to native artery and investigate the regenerative capacity of the conduit using ovine vascular cells. Methods Porcine carotid arteries were harvested and decellularized using an established protocol. In short, arteries were treated sequentially with EDTA, hypotonic buffer, 0.1% (w/v) sodium dodecyl sulphate (SDS), DNase and RNase, hypertonic buffer and sterilised using 0.1% (v/v) peracetic acid. In order to determine the biomechanical properties of the acellular arteries, suture retention strength, ultimate tensile strength and burst pressure measurements were performed in comparison to native tissue. Ovine endothelial cells were harvested from the femoral arteries of sheep following digestion with collagenase. Ovine smooth muscle cells were isolated from ovine arterial explant cultures. The phenotype of the cells was confirmed using antibodies to ovine vascular cell markers (myosin, α-actin, VWF, CD62) by indirect immunofluorescence.. Biocompatability of the scaffolds was assessed using contact and extract cytotoxicity tests with two cell lines (BHK and 3T3) and primary ovine vascular cells (endothelial and smooth muscle cells). The capacity of the acellular arteries to support vascular cell adhesion was determined by seeding cells onto the scaffolds and evaluation using scanning electron microscopy (SEM).. Results Histiological characterization and DNA quantification confirmed successful decellularization of porcine carotid arteries. Decellularized vessels were shown to retain the biomechanical strength and properties of native vessels. Decellularized arteries displayed no evidence of cytotoxicity to cell lines or primary vascular cells. Initial cell adhesion studies confirmed successful adherence of ovine vascular cells to decellularized arteries. Conclusion The study resulted in an acellular, biocompatible scaffold that retained the biomechanical properties of the native artery. Initial re-cellularization studies with ovine vascular cells was successful.