Endothelial implants provide long-term control of vascular repair in a porcine model of arterial injury

Cell culture and animal data support the role of endothelial cells and endo thelial-based compounds in regulating vascular repair after injury. We desc ribe a long-term study in pigs in which the biological and immunological re sponses to endothelial cell implants were investigated 3 months after angio plasty, approximately 2 months after the implants have degraded. Confluent porcine or bovine endothelial cells grown in polymer matrices were implante d adjacent to 28 injured porcine carotid arteries. Porcine and bovine endot helial cell implants significantly reduced experimental restenosis compared to control by 56 and 31%, respectively. Host humoral responses were invest igated by detection of an increase in serum antibodies that bind to the bov ine or porcine cell strains used for implantation. A significant increase i n titer of circulating antibodies to the bovine cells was observed after 4 days in all animals implanted with xenogeneic cells. Detected antibodies re turned to presurgery levels after Day 40. No significant increase in titer of antibodies to the porcine cells was observed during the time course of t he experiment in animals implanted with porcine endothelial cells. No impla nted cells, Gelfoam, or focal inflammatory reaction could be detected histo logically at any of the implant sites at 90 days. These data suggest that t issue-engineered endothelial cell implants may provide longterm control of vascular repair after injury, rather than simply delaying lesion formation and that allogeneic implants are able to provide a greater benefit than xen ogeneic implants. (C) 2001 Academic Press.