Dual cell seeding and the use of zymogen tissue plasminogen activator to improve cell retention on polytetrafluoroethylene grafts

Abstract

Objective: The purpose of this study was to enhance the retention of seeded endothelial cells (EC) on prosthetic vascular grafts. Dual-layer EC and smooth muscle cell (SMC) seeding and gene transfer of a zymogen tissue plasminogen activator gene (tPA) into seeded EC were studied. Methods: Polytetrafluoroethylene (PTFE) grafts were precoated with fibronectin, seeded with SMC followed by EC a day later, and then, 24 hours later, exposed to an in vitro flow system for 1 hour. Cell retention rates were determined for grafts seeded with EC only, a dual layer of EC on top of SMC, EC transduced with wild-type tPA, and EC transduced with zymogen tPA. Results: Seeding efficiency of PTFE pretreated with fibronectin was 260 ± 8 cell/mm2. After exposure to flow, only 39% ± 14% of the EC were retained when EC were seeded alone, whereas 73% ± 22% of EC remained on grafts when EC were seeded on top of SMC (P