Prolonged Cold Ischemia Time in Mouse Heart Transplantation Using Supercooling Preservation

Background. Supercooling preservation techniques store a donor organ below 0 degrees C without freezing. This has great advantages in inhibiting metabolism and preserving the organ in comparison to conventional preservation at 4 degrees C. We developed a novel supercooling technique using a liquid cooling apparatus and novel preservation and perfusion solutions. The purpose of this study was to evaluate the preservation effect of our supercooling preservation technique in a mouse heart transplantation model. Methods. Syngeneic heterotopic heart transplantation was performed in 3 groups of mice: (1) the nonpreservation group, in which the cardiac grafts were transplanted immediately after retrieval; (2) the conventional University of Wisconsin (UW) group, in which the cardiac grafts were stored in UW solution at 4 degrees C for different periods of time; and (3) the supercooling group, in which the cardiac grafts were stored in a novel supercooling preservation solution at -8 degrees C for different periods of time. The maximal preservation time was investigated. Twenty-four-hour sample data were collected and analyzed to compare supercooling preservation to conventional UW preservation. Results. Our technique yielded a stable -8 degrees C supercooling state. Cardiac graft revival was successfully achieved after supercooling preservation for 144 hours, and long-term survival was observed after supercooling preservation for 96 hours. Posttransplant outcomes, including myocardial ischemia-reperfusion injury, oxidative stress-related damage, and myocardial cell apoptosis, were improved in comparison to conventional 4 degrees C UW preservation. Conclusions. Supercooling heart preservation at -8 degrees C greatly prolonged the preservation time and improved the posttransplant outcomes in comparison to conventional 4 degrees C UW preservation. Supercooling preservation is a promising technique for organ preservation.