Abstract 13054: Perfect 1 Year Angiographic Patency of in vivo Tissue-Engineered Vascular Grafts With an Ultra Small Diameter of 0.6 mm (MicroBiotubes) in a Rat Model

Abstract

Background and Purpose: Biotubes are autologous tubular connective tissues formed by in-body tissue architecture technology, which is a novel and practical approach in regenerative medicine. We confirmed that Microbiotubes (MBs) with diameter of 0.6 mm had high performance potential as a reliable arterial graft in acute phase of implantation in a rat model. In this study, quality and patency of MBs in chronic phase were evaluated by histological or magnetic resonance angiographic (MRA) examinations, respectively. Method: The mold for multiple preparing of MBs was assembled by several stainless wires covered with silicone tubes. The molds were surgically embedded into the dorsal subcutaneous pouches of rats. After 2 months, the molds were harvested with surrounding tissues and MBs were obtained by removing the molds. MBs (length, 10 mm; internal diameter, 0.6 mm) were implanted in rat femoral arteries (diameter, ca. 0.5 mm) in allogenic manner by end-to-end anastomosis without use of any anticoagulant agents. Ten patent MBs after 1-month implantation were observed by follow-up 7- Tesla MRA until 1 year after implantation. Results: In all follow-up periods, all MBs were patent without any observable stenoses or dilatations and a difference of signal intensity between MBs and native artery was obscure (Fig. 1). Moreover, native-like reconstructed structure of MBs’ wall was conserved histologically for 1 year. Conclusion: It was unprecedented result that there was no occluded case in chronic phase and MBs preserved high quality and patency for a long-term period. We are convinced that MBs could be useful grafts for ultramicrosurgery, such as a replantation of severed fingers or a reconstruction of lymphatic vesssels, in the not too distant future.