AUTOLOGOUS ARTIFICIAL HEART VALVES (BIOVALVES) BASED ON ???IN BODY TISSUE ARCHITECTURE??? TECHNOLOGY

Background: In vivo tissue-engineered trileaflet valves with simple polymeric support scaffolds were developed under the new practical concept of regenerative medicine “in body tissue architecture” technology, based on tissue-encapsulation phenomenon for foreign materials. Method: Crown-shaped microporous polyurethane (PU) tubes with 3 horns (internal diameter; 5 and 20mm) were specially designed as scaffolds. Silicone rod molds were inserted into the scaffolds, which were placed into dorsal subcutaneous spaces of Japan white rabbits (n=4). Histological and mechanical features of the implants were evaluated after 4 weeks. Results: The scaffolds were completely covered with membranous tissues consisting of autologous collagen rich extracellular matrices and fibroblasts. After trimming the formed membranous tissues between the 3 horns of the scaffolds and removal the silicone molds, “Biovalves” with three autologous leaflets were obtained. The tensile strength of the leaflets was equivalent to that of porcine aortic valve leaflets. Excellent valvular performances were demonstrated under pulsatile condition using a flow loading circuit. No regurgitation was observed at the physiological hydrostatic pressure up to 60mmHg. Conclusion: New in vivo tissue-engineered trileaflet valves “Biovalves” were successfully produced by “in body tissue architecture” technology. Since the “Biovalves” are composed only of autologous tissues and biodegradable scaffolds, they could be ideal prosthetic heart valves with high biocompatibility and high “bioadaptability” for growing recipients.