Tracheal Replacement Using an In-Body Tissue-Engineered Collagenous Tube "BIOTUBE" with a Biodegradable Stent in a Beagle Model: A Preliminary Report on a New Technique.

Introduction:  Tracheal reconstruction for long-segment stenosis remains challenging. We investigate the usefulness of BIOTUBE, an in-body tissue-engineered collagenous tube with a biodegradable stent, as a novel tracheal scaffold in a beagle model.

Materials And Methods:  We prepared BIOTUBEs by embedding specially designed molds, including biodegradable stents, into subcutaneous pouches in beagles. After 2 months, the molds were filled with ingrown connective tissues and were harvested to obtain the BIOTUBEs. The BIOTUBEs, cut to 10- or 20-mm lengths, were implanted to replace the same-length defects in the cervical trachea of five beagles. Endoscopic and fluoroscopic evaluations were performed every week until the lumen became stable. The trachea, including the BIOTUBE, was harvested and subjected to histological evaluation between 3 and 7 months after implantation.

Results:  One beagle died 28 days after 20-mm BIOTUBE implantation because of insufficient expansion and retention force of the stent. The remaining four beagles were implanted with a BIOTUBE reinforced by a strong stent, and all survived the observation period. Endoscopy revealed narrowing of the BIOTUBEs in all four beagles, due to an inflammatory reaction, but patency was maintained by steroid application at the implantation site and balloon dilatation against the stenosis. After 2 months, the lumen gradually became wider. Histological analyses showed that the internal surface of the BIOTUBEs was completely covered with tracheal epithelial cells.

Conclusion:  This study demonstrated the usefulness of the BIOTUBE with a biodegradable stent as a novel scaffold for tracheal regeneration.