Tissue-engineered vascular autograft: Inferior vena cava replacement in a dog model

Tissue-engineered vascular autografts (TEVAs) were made by seeding 4-6 x 10 (6) of mixed cells obtained from femoral veins of mongrel dogs onto tube-sh aped biodegradable polymer scaffolds composed of a polyglycolid acid (PGA) nonwoven fabric sheet and a copolymer of L-lactide and caprolactone (n = 4) . After 7 days, the inferior vena cavas (IVCs) of the same dogs were replac ed with TEVAs. After 3, 4, 5, and 6 months, angiographies were performed, a nd the dogs were sacrificed. The implanted TEVAs were examined both grossly and immunohistologically. The implanted TEVAs showed no evidence of stenos is or dilatation. No thrombus was found inside the TEVAs, even without any anticoagulation therapy. Remnants of the polymer scaffolds were not observe d in all specimens, and the overall gross appearance similar to that of nat ive IVCs. Immunohistological staining revealed the presence of factor VIII positive nucleated cells at the luminal surface of the TEVAs. In addition, lesions were observed where alpha -smooth muscle actin and desmin positive cells existed. Implanted TEVAs contained a sufficient amount of extracellul ar matrix, and showed neither occlusion nor aneurysmal formation. In additi on, endothelial cells were found to line the luminal surface of each TEVA. These results strongly suggest that "ideal" venous grafts with antithrombog enicity can be produced.