A new and simple technique to achieve a confluent and flow resistant endothelium on vascular ePTFE-grafts using human serum

Abstract

Confluent endothelialisation of vascular grafts in vitro before implantation has been suggested as a way to improve patency. With the aim of creating a confluent endothelium or expanded polytetrafluoroethylene (ePTFE) vascular grafts, using a minimum of allo- or xenogenic material, we have investigated the use of human serum for endothelial cell (EC) growth and adhesion to the grafts. Loss of fibronectin from the serum was measured before and after coating. After serum- or collagen I-precoating, the grafts were seeded with cultured adult human endothelial cells from the great saphenous vein and then kept under rotational culture conditions for 2 days. To evaluate the endothelial resistance to detachment the grafts were mounted in parallel to a heart-lung machine, delivering a pulsatile flow of human blood for 1 hour. Evaluation was performed using scanning electron microscopy (SEM). By simply pressing serum through the graft wall, fibronectin corresponding to 19 micrograms/cm2 graft surface was consumed. It was possible to achieve a confluent endothelium on both serum- and collagen I-precoated grafts (n = 8). After being subjected to blood flow, SEM revealed a complete endothelial lining of the grafts (n = 12) except for two serum-precoated grafts which showed < or = 10% and between 10 and 20% denuded areas, and one collagen-coated graft that showed < or = 10% of denuded area. This method provides a way to achieve a confluent and flow resistant endothelial lining on ePTFE vascular grafts.