Fibronectin coating of an experimental PTFE vascular prosthesis

Abstract

Because of the known inefficiency of endothelial cell seeding of vascular prostheses, some investigators have pretreated their grafts with fibronectin in an effort to increase endothelial cell adhesion. However, the most efficient method of coating vascular prostheses with fibronectin has not yet been determined and more importantly, the durability of this coating following restoration of pulsatile perfusion has not yet been established. This experiment measured the adsorption of fibronectin which was perfused at three different concentrations through an experimental, highly porous PTFE vascular graft. Most efficient coating of the prosthetic appeared to occur with a 250 mg/ml concentration of fibronectin perfused through the graft for 60 min. Grafts so prepared were subsequently studied in a pulsatile perfusion system which mimicked the canine circulation. Fifteen additional fibronectin-coated grafts were also interposed in the canine carotid artery. Flow was restored, grafts were removed at varying intervals, and fibronectin disappearance was measured. In both the in vitro and in vivo models, three distinct phases of fibronectin dissociation were seen: an initial rapid loss which resulted in an average 30.5% retention of the initial concentration of fibronectin following 30 min of perfusion; a second phase, which occurred from 30 to 120 min, demonstrated an average 2.5% loss of fibronectin per hour; and a final phase, from 2 to 24 hr, during which no significant additional loss of fibronectin was seen. This study describes a new method by which PTFE vascular prostheses can be effectively coated by perfusing them with physiologic concentrations of fibronectin and demonstrates that the resulting bond between fibronectin and prosthetic is stable following restoration of pulsatile flow.