The Effects of the Warm Ischemic Time, the Preserving Temperature and the Cryopreservation Solution on the Viability of Tracheas

Sa, Young Jo; Park, Jae Kil; Sim, Sung Bo; Jin, Ung; Moon, Young Kyu; Lee, Sun Hee; Jo, Kuhn Hyun

Abstract

BACKGROUND: Tracheal reconstruction after extended tracheal resection still remains as a major surgical challenge because good clinical outcomes are usually correlated with limited tracheal resection. Recent investigations with a using cryopreserved trachea for the reconstruction of a trachea have been carried out to overcome this problem. In this study, we analyzed viability of tracheas, which is an important determining factor for the success of transplanting a cryopreserved trachea and the development of post-transplantation tracheal stenosis, according to three different experimental factors: 1) the warm-ischemic time, 2) the cryopreservation solution and 3) the preserving temperature, to determine a better cryopreservation protocol and a better composition of the cryopreservation solution. MATERIAL AND METHOD: Rats tracheas were harvested for different warm-ischemic times (0 hr, 12 hrs, 24 hrs). The tracheas were treated with recombinant insulin growth factor-1 (IGF-1) and they were stored at three different temperatures (4 degreesC, -80 degreesC, -196 degreesC) for two weeks. After two weeks, we thawed the stored trachea and isolated the cells of the tracheas with using type II collagenase. We cultured the cells for seven days and then we compared the cellular viability by the MTT reduction assay. RESULT: Though cryopreservation is required to preserve a trachea for a longer time period, the viability of the tracheas stored at -80 degreesC and -196 degreesC was significantly reduced compared to that of the tracheas stored at 4 degreesC. The viability of the tracheas with warm-ischemic times of 12 hrs and 24 hrs was also reduced in comparison to the tracheas with a warm-ischemic time of 0 hrs.Department of Thoracic and Cardiovascular Surgery, St. Mary's Hospital, The Catholic University of Korea College of Medicine Our data showed that the warm ischemic time and the parameters of cryopreservation negatively affect on trachea viability. However, a cryopresrvation solution containing IGF-1 improved the cellular viability better than the existing cryopreservation solution. For the warm ischemic time group of 0 hr, the addition of IGF-1 improved the viability of trachea at all the preserving temperatures.
CONCLUSION
These experiments demonstrate that the viability of a cryopreserved trachea can be improved by modifying the components of the cryopreservation solution with the addition of IGF-1 and reducing the warm-ischemic time.