Daizo Ishii1, Jun-Ichiro Enmi2, Ryosuke Iwai3, Kaoru Kurisu4, Eisuke Tatsumi5, Yasuhide Nakayama6. 1. Department of Artificial Organs, National Cerebral and Cardiovascular Centre Research Institute, Japan; Department of Neurosurgery, Hiroshima University Graduate School of Biomedical and Health Sciences, Japan. 2. Department of Investigative Radiology, National Cerebral and Cardiovascular Centre Research Institute, Japan. 3. Department of Artificial Organs, National Cerebral and Cardiovascular Centre Research Institute, Japan; Research Institute of Technology, Okayama University of Science, Japan. 4. Department of Neurosurgery, Hiroshima University Graduate School of Biomedical and Health Sciences, Japan. 5. Department of Artificial Organs, National Cerebral and Cardiovascular Centre Research Institute, Japan. 6. Department of Artificial Organs, National Cerebral and Cardiovascular Centre Research Institute, Japan. Electronic address: nakayama@ncvc.go.jp.
Abstract
OBJECTIVE: The world's smallest calibre "microbiotube" vascular graft was recently developed, with an inner diameter of 0.6 mm. It was formed using in-body tissue architecture (iBTA) and has a high degree of patency and capacity for regeneration in the acute phase, 1 month after implantation. This consecutive study investigated the compatibility and stability of microbiotubes in the chronic phase of implantation for 12 months for potential application in microsurgery. METHODS: This was an in vivo experimental study. The microbiotubes were prepared by embedding the mould subcutaneously in rats for 2 months. Allogenic microbiotubes (n = 16) were implanted into the bilateral femoral arteries (inner diameter 0.5 mm) of eight Wistar rats in an end to end anastomosis manner for 12 months. Follow up 7-Tesla magnetic resonance angiograms were performed every 3 months. Histological observation was performed 12 months after implantation. RESULTS: All patent grafts (n = 12, patency 75%) one month after implantation maintained their patency up to 12 months without any abnormal morphological changes or calcification. Histological observation at 12 months showed that layered α-smooth muscle actin positive cells with a monolayer luminal covering of endothelial cells had formed from the proximal to the distal anastomoses. A thin elastic fibre layer formed in the luminal area. After implantation, all components of the microbiotube were similar to those of a native artery. CONCLUSIONS: This study suggests that microbiotubes have high compatibility, stability, and durability as replacement grafts over the short to mid-term period.
OBJECTIVE: The world's smallest calibre "microbiotube" vascular graft was recently developed, with an inner diameter of 0.6 mm. It was formed using in-body tissue architecture (iBTA) and has a high degree of patency and capacity for regeneration in the acute phase, 1 month after implantation. This consecutive study investigated the compatibility and stability of microbiotubes in the chronic phase of implantation for 12 months for potential application in microsurgery. METHODS: This was an in vivo experimental study. The microbiotubes were prepared by embedding the mould subcutaneously in rats for 2 months. Allogenic microbiotubes (n = 16) were implanted into the bilateral femoral arteries (inner diameter 0.5 mm) of eight Wistar rats in an end to end anastomosis manner for 12 months. Follow up 7-Tesla magnetic resonance angiograms were performed every 3 months. Histological observation was performed 12 months after implantation. RESULTS: All patent grafts (n = 12, patency 75%) one month after implantation maintained their patency up to 12 months without any abnormal morphological changes or calcification. Histological observation at 12 months showed that layered α-smooth muscle actin positive cells with a monolayer luminal covering of endothelial cells had formed from the proximal to the distal anastomoses. A thin elastic fibre layer formed in the luminal area. After implantation, all components of the microbiotube were similar to those of a native artery. CONCLUSIONS: This study suggests that microbiotubes have high compatibility, stability, and durability as replacement grafts over the short to mid-term period.