Optimal seeding conditions for human endothelial cells.

An in vitro model of endothelial cell seeding has been developed to individually evaluate the steps required for seeding arterial prostheses. Human saphenous vein endothelial cells are radiolabeled with tritiated thymidine and seeded onto 4 mm polytetrafluoroethylene grafts. Grafts are then placed into a perfusion circuit for determination of cellular retention. Using this model, the following variables were studied: (1) graft coating (fibronectin versus serum versus plasma); (2) time of incubation of cells with graft (0, 20, 90 minutes); (3) density of the initial seeding solution (4 x 10(3)-6 x 10(5) cells/cm2). The data suggest that incubation of a graft with plasma provides an adhesive surface that is as effective as fibronectin for enhancing cell retention. With this particular model, seeding densities between 1 and 2 x 10(5) cells/cm2 produce a confluent monolayer with optimal utilization of cells. A shorter 20 minute incubation period resulted in the retention of only half of the seeded cells, while postperfusion attachment increased significantly with a 90 minute incubation period. Data derived from this system can be used to construct a protocol that may be useful for clinical in vivo seeding trials.