Effects of Deep Hypothermic Preservation on Posttransplant Viability of Tracheal Grafts

Abstract

Objective Using an animal model, we performed a study to assess the effects of rapid freezing in the absence of cryoprotectants on the viability of tracheal grafts after allotransplantation. Materials and methods Ten tracheal heterotopic transplantations were performed with fresh grafts just after harvesting donors, and 20, with cryopreserved specimens at 2 or 6 weeks after hypothermic storage. Cryopreservation consisted of rapid cooling in the absence of cryoadditives with storage for 2 weeks at −80°C. After rewarming, grafts were transplanted into the abdominal cavity of immunosuppressed rats by being embedded into the greater omentum. Fourteen days later, the implants were removed to examine chondrocyte viability, submucosal swelling, and epithelial patterns in comparison with fresh controls. Results All allografts retained their macroscopic structure after transplantation. Respiratory epithelium was substituted by planar epithelium only in the frozen transplanted specimens. Fresh transplanted grafts exhibited 100% chondral viability in contrast with 5% viability observed among cryopreserved tracheas after transplantation. Conclusions The method of rapid freezing was effective to preserve airway grafts. However, the quality of cryopreserved cartilage was disappointing, similar to that obtained using conventional slow-freezing protocols.