Elevated platelet-derived growth factor production by aortic grafts implanted on a long-term basis in a canine model

An endothelial cell lining in a prosthetic vascular graft has been shown to decrease graft thrombogenicity. However, previous studies in our laboratory demonstrated that grafts seeded with endothelial cells produced platelet-derived growth factor, a potent smooth muscle cell mitogen that may promote intimal hyperplasia. This study was undertaken to assess temporal changes in platelet-derived growth factor production by grafts seeded with endothelial cells and unseeded grafts and adjacent arteries. Adult beagles underwent placement of 20 to 22 cm long, 8 mm inner diameter, expanded polytetrafluoroethylene thoracoabdominal aortic grafts that were either seeded with autologous jugular vein endothelial cells or were unseeded controls. Grafts and adjacent arteries were removed at times up to 2 years after implantation. The tissue was studied in organ culture and platelet-derived growth factor production was measured after 72 hours with use of a radioreceptor assay. Platelet-derived growth factor production by endothelialized grafts increased significantly over the period studied, especially at the anastomoses, whereas that by arterial segments did not change significantly. The increase in platelet-derived growth factor production was greater in the distal than the proximal anastomotic segment suggesting a possible explanation for the clinical finding of more severe intimal hyperplasia at the distal anastomosis.