| Co-Investigator(Kenkyū-buntansha) |
NAGAOKA Shoji Toray Basic Research Institute, Senior Scientist, 基礎研究所, 主任研究員
MIYATA Teruo Koken Biosciences Institute, Director, バイオサイエンス研究所, 所長
KOYAMAGI Hitishi Tokyo Women's Medical College, Professor, 教授 (90138884)
WATARAI Hiroshi Okayama University, Assistant Professor, 医学部, 助手 (50175139)
YASUDA Tatsuji Okayama University, Professor, 医学部, 教授 (30092357)
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| Research Abstract |
The safetyness of a vascular graft that can grow with the growth of its reciepient was evaluated during long-term implantation in experimental animals. For this experiment, we developed a special grwoable vascular graft from collagenous biological materials along the following procedure : Human saphenous vein was used as the substrate material. It was dipped into distilled water and sonicated, resulting in cell destruction ; and followed by cross-linking with a polyepoxy compound to give both controlled biodegradability, hydrophilicity, and antithrombogenic properties.
At first short-term evaluation was performed. Four millimeter inner diameter (ID) grafts, enveloped with polyester mesh tubes of 10 nun ID, were implanted in 11 puppies, The diameter of the grafts grew to 6.5 mm from original 4 mm after 6 month. Then the long-term evaluation was performed. The grafts 4 mm ID, enveloped with a polyester mesh tube of 10 mm ID were implanted in 15 puppies. The diameter of the graft grew to 9.5 mm after 1 year from the original 4 mm, and remained stabel for 2 years and 7 months of observation. The newly formed neointima reinforced with polyester mesh was composed of smooth muscle cells covered with endothelial cells. The original vein graft was completely absorbed, and there were no degenerative changes such as calcification or aneurysmal dilatation. The graft maintained the expected side for long period of time.
For the growable vascular graft, the following requirements were provided : 1) antithrombogenicity in a small caliber graft ; 2) ability to grow as well as to terminate growth. The polyester mesh tube, which was larger than the graft, caused arrest of growth at the expected diameter, whereas the growth rate was controlled by the degree of graft cross-linking. With this method, any size graft can be made by changing tlie size of the original graft and the polyester mesh tube around it.
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