Endothelial cell seeding of small diameter vascular grafts

This study examines, under flow conditions, the adhesion of endothelial cells to 3 mm diameter fibronectin (Fn)-coated expanded polytetrafluoroethylene (PTFE) vascular grafts. Cultured ovine carotid artery endothelial cells were labelled with 35S-methionine. The grafts were seeded with endothelial cells (1.5 x 10(6)/ml) by rolling for 1 h at 37 degrees C and then either cultured to confluence for 48 h or flow tested immediately. Cell attachment to grafts (n = 5) was evaluated in an in vitro flow circuit, using flows of up to 330 ml/min. Ex vivo studies (n = 5 grafts) were conducted without anticoagulant using autologous cells in a sheep model. Grafts were inserted into an externalized carotid-jugular shunt and exposed to blood flows of approximately 150 ml/min for 3 h. One hour seeded and 48 h cultured grafts demonstrated greater than 95% cell retention following in vitro flow studies. Ex vivo studies of 48 h cultured grafts gave endothelial cell retention of 81% with no sign of thrombogenicity. Furthermore, a preliminary 24 h ex vivo study has shown greater than 95% retention. This study demonstrates the firm attachment of seeded endothelial cells to Fn-coated PTFE grafts in the sheep model.