Abstract 13032: Evidence of Dimensional Adaptability of in vivo Tissue-engineered Allogenic “Biotube” Vascular Grafts in a Growing Canine Model

Abstract

Introduction: In pediatric surgery, size mismatch inducing between artificial vascular grafts and growing recipients vessels remains a serious problem to be solved. Biotubes are autologous connective tissue tubes, formed by in body tissue architecture technology (IBTA), which is a novel and practical approach of regenerative medicine based on the tissue encapsulation phenomenon. This study aimed to evaluate the growth potential of Biotubes by examining their caliber and length adaptation to growing native arteries after implantation. Allogenic implantation of Biotubes pre-prepared from adult beagles was performed to juvenile beagles. Methods and Results: IBTA-based Biotubes (internal diameter 3 mm, length 1 cm) were prepared in adult beagles (age, 1 year; weight ca. 10 kg) by subcutaneous embedding of silicone-based molds for 2 months. The obtained allogenic collagenous Biotubes (n=8) were implanted into the common carotid artery (internal diameter, 2 mm) of juvenile beagles (n=8, age 11 weeks, weight ca. 3 kg). In all cases, there was no aneurysm or stenosis formation with perfect patency for all observation periods. Almost complete vascular remodeling occurred only at 1 month of implantation. Follow-up angiogram showed that diameter of Biotubes was gradually expanded with that of the growing host arteries almost in the same way. In 1-year after implantation, there was little gap between them by ca.1.5-times of diameter expansion in Biotube. Interestingly, macroscopic observation showed elongation of Biotubes to ca 1.3 times in maximum. Conclusions: Even in allogenic manner, vascular reconstruction of Biotube to layered vascular tissue successfully occurred. After vascular reconstruction, Biotubes could be extended and expanded according to the growing native arteries. The growth potential of Biotubes was indicated in this animal experimental model for the first time. Biotubes have high potential usefulness in pediatric surgery.