Over 65% of small and medium sized synthetic vascular grafts occlude within 5 years of implantation. It has long been known that coating the luminal surface with endothelial cells (EC's) prior to implantation significantly extends the life of the graft, yet no commercially viable clinical systems have been developed. The goal of this work is to develop a commercially viable method of endothelializing the luminal surface of synthetic vascular grafts based on the electrostatic seeding method. The electrostatic method accomplishes implantation by temporarily altering the prosthetic graft lumenal surface charge to a more positive state, which results in an increased total number of adhered and flattened EC's compared to other methods. The flattened phase is important because it minimizes the loss of EC's upon exposure to fluid shear stress. Electrostatic seeding is rapid, taking only 16 minutes compared to days for the gravitational seeding method. The original electrostatic technique works well for relatively short grafts (<15cm), but presents severe limitations for longer grafts and commercial packaging systems. Our enhanced method promises to retain all of the advantages of the original technique while also overcoming the graft length restrictions and packaging issues. Testing will demonstrate that these improvements apply equally well to short (6cm) and long (80cm) e-PTFE grafts, and will result in the same seeding densities as the original technique. Tests will also demonstrate that the enhanced technique results in the same short seeding times, high cell viability, high degree of maturation (flattening), and low degree of cellular damage. In addition, tests using physiologic shear flow conditions (15 dynes/cm2) will demonstrate that, independent of graft length, the EC's are retained on the graft walls equally as well as the original technique. Key Words: electrostatic cell seeding, synthetic vascular graft, endothelial cells, human umbilical vein endothelial cells, expanded polytetrafluoroethylene (ePTFE).
Thesaurus Terms: cardiovascular transplantation, cell transplantation, method development, surface coating, vascular endothelium apical membrane, blood flow, cell adhesion, cell morphology, electrical property, shear stress, surface property human tissue, tissue /cell culture
