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KMID : 0378620030190000077
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Baptist Hospital Medical Journal
2003 Volume.19 No. 0 p.77 ~ p.83
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Tissue Engineered Heart Valve Leaflet
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이택연/Lee, Taek-Yeon
방정현/Bang, Jung Hyeon
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Abstract
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Heart valve replacement with either a bioprosthesis or a mechanical prosthesis is an effective therapy for valvular heart disease. However both of these valves have limitations, including their inability to grow. repair, and remodel. In addition, a mechanical valve requires long term anticoagulation therapy.
Tissue engineered heart valve is considered a promising way of overcoming these problems.
The aim of this study was to evaluate the feasibility of valve leaflet for autologous ovine vascular cells and biodegradable polymers by tissue engineering techniques and compare .the biological response of an autologous cell seeded scalffold and cellular scaffold implanted in the·pulmonary valve leaflet in the same animal.
Myofibroblasts and endothelial cells were isolated and cultured from an ovine carotid artery. Asynthetic biodegradable scaffold consisting of polyglycolic acid and polylactic acid was initially seeded with the myofbroblasts, after then coated with endothelial cells. Cells were seeded using a medium containing collagen and cultured. The tissue engineered constructs and the plain scaffold were implanted as double pulmonary valve leaflets replacement in the same ovine models(n=3). Additionally, the tissue engineered constructs (n=2) and the plain scaffold (n=2) were implanted as single valve leaflet placements for long-term analysis.
After sacrificing, the implaned valve leaflet tissues were retrieved and analyzed grossly and microscopically
Three animals, which underwent replacement of two valve leaflets with a tissue engineered construct and a plain scaffold, survived only a short time(12, 24, 36, hours). Their deaths were attributed to acute right ventricular failure which was resulted from severe pulmonary insufficiency. Animals that underwent single valve leaflet replacement survived longer and were sacrificed at 6 and 9 weeks after operation. The analysis of the leaflets from the short-term survivors showed that the tissue engineered constructs contained less fibrins and protein exudates than the plain scaffold. In contrast, leaflets obtained form animals surving 6 and 9weeks showed similar well organized granulation tissues in the tissue engineered constructs and the plain scaffold.
This animal experiment demonstrates that in the early phase of implantation, the tissue engineered constuct shows a better biological response in terms of antithrombogenectiy than the plain scaffold, although both of them give similar results in the later reparative phase.
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