The effect of fibronectin coating on endothelial cell kinetics in polytetrafluoroethylene grafts

Abstract

Despite the proven experimental success of endothelial cell seeding of prosthetic vascular grafts, the process has not been widely accepted for clinical use because of its complexity and the need for a relatively large length of autologous vein to provide the requisite number of cells. Using autologous endothelial cells radiolabeled with indium 111-oxine, we studied the effect of fibronectin coating of polytetrafluoroethylene grafts in a canine carotid interposition model on initial endothelial cell adherence and subsequent cell retention for up to 72 hours following restoration of blood flow. Since the number of harvested endothelial cells varied widely depending on the diameter and length of available vein, cellular adherence was best expressed as a percentage of the original cell harvest. More than twice as many (46.7% vs. 19.8%) endothelial cells initially adhered to fibronectin-coated grafts compared with uncoated control grafts. Fibronectin did not appear to influence the loss of cells within the first 30 minutes following restoration of blood flow. However, over the next 24 hours, it clearly reduced the mean cell loss from 3.7%/hr to 2.2%/hr and resulted in a sixfold increase (21.3% vs. 3.4%) in the number of retained cells at the end of a 24-hour period. When the endothelial cell preclot was performed with a solution of culture medium 199, as opposed to heparinized whole blood, there was no significant difference in endothelial cell retention. Assuming that such increases in seeding density will result in more rapid growth to confluence of the endothelial layer, pretreatment with fibronectin may shorten the period during which grafts remain vulnerable to thrombosis and infection and may significantly reduce the length of autologous vein necessary to seed a given length of prosthesis.