title: In situ observation and enhancement of leaflet tissue formation in bioprosthetic "biovalve".
abstract: Biovalves, autologous tri-leaflet valved conduits, are formed in the subcutaneous spaces of animals. The valves are formed using molds encapsulated with autologous connective tissues. However, tissue migration into the small apertures in the molds for leaflet formation is generally slower than that for conduit formation around the molds. In this study, the formation of the leaflet tissues was directly and non-invasively observed using a wireless capsule endoscope. The molds were assembled from 6 parts, one of which was impregnated with the endoscope, and embedded into subcutaneous pouches in goats (n = 30). Tissue ingrowth into the apertures gradually occurred from the edges of the leaflet parts. Tissue formation was accompanied by capillary formation. At 63.1 ± 17.1 days after embedding, the apertures were completely replaced with autologous connective tissue, forming the leaflet tissues. Leaflet formation was enhanced by including fat tissue (46.7 ± 4.2 days) or blood (41.1 ± 6.9 days) in the apertures before embedding. The creation of slit openings, in conjunction with addition of blood to the apertures, further enhanced leaflet formation (37.0 ± 2.8 days). Since leaflet formation could be observed endoscopically, the appropriate embedding period for complete biovalve formation could be determined.
authors.affiliation: Division of Medical Engineering and Materials, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka, 565-8565, Japan.
authors.forename: Marina
authors.initials: M
authors.lastname: Funayama
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Takewa
authors.forename: Tomonori
authors.initials: T
authors.lastname: Oie
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Matsui
authors.forename: Eisuke
authors.initials: E
authors.lastname: Tatsumi
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Nakayama
mesh_terms: D000818:Animals; D001705:Bioprosthesis; D006348:Cardiac Surgical Procedures; D006041:Goats; D006350:Heart Valve Prosthesis; D011474:Prosthesis Design; D023822:Tissue Engineering