ENDOTHELIALIZED BIOLOGICAL HEART-VALVE PROSTHESES IN THE NONHUMAN PRIMATE MODEL

Objective: The main disadvantage of implanted cardiac valve bioprosthe ses remains primarily tissue failure due to calcification. Coating of bioprostheses with viable autologous endothelial cells may delay or ev en eliminate tissue calcification and subsequent cardiac dysfunction. Methods: Glutaraldehyde-preserved Hancock bioprostheses (n = 5), pretr eated with glutamic acid (8%) and cryopreserved allografts (n = 5) wer e lined, using endothelial cells harvested from the external jugular v ein. Coated specimens were cultivated for 9 days in Medium 199 supplem ented with 20% fetal calf serum and basic fibroblast growth factor. En dothelialized grafts were anastomosed into the descending thoracal aor ta of adult Chacma baboons. Untreated valve bioprostheses (n = 4) serv ed as controls. Forty days after implantation the prostheses were exam ined morphologically and immunohistochemically. Results: After implant ation endothelialized prostheses showed a positive Factor VIII related antigen reaction by immunohistochemistry on all valve surfaces. Scann ing electron microscopy showed confluently lined leaflets with transpl anted endothelial cells and displayed cobblestone morphology on all co ated allografts. In contrast, the surface of pretreated xenograft valv es revealed uncoated areas with platelet and leucocyte aggregates. No endothelium was observed on the leaflets of untreated controls 40 days after implantation. Conclusion: In vitro endothelialization of cardia c valve bioprostheses with autologous endothelial cells is possible. T he newly created endothelium is shear stress resistant and the antithr ombotic as well as the antiaggregatory capacity of the transplanted ce lls were retained. Lining with autologous endothelial cells could impr ove the durability and clinical outcome of biological valve prostheses . (C) 1997 Elsevier Science B.V.