Permanent life support by kidneys perfused with a vitrifiable (7.5 molar) cryoprotectant solution

BACKGROUND: Vitrification (glass formation) is a potential method for indefinite term organ preservation that eliminates all of the conventional problems of freezing and thawing. A 7.5 M mixture of cryoprotectants known as VS4 is sufficiently concentrated, in combination with applied pressure, to preclude ice formation entirely during cooling to below the glass transition temperature (about -125 degrees C), at which point vitrification takes place, arresting further changes over time. METHODS: Rabbit kidneys were perfused with VS4 according to three different protocols. The kidneys were evaluated using an autograft model with immediate contralateral nephrectomy. RESULTS: All three methods permitted long-term survival, but the best results were obtained when the highest concentrations were perfused at about -3 degrees C. Using the latter protocol, the survival rate was 10/10, serum creatinine returned to a normal baseline after transient elevation, other clinical chemistry results normalized, and no histological damage was apparent 3 weeks after autografting. CONCLUSIONS: The results described provide the strongest evidence to date that it may be possible to bank kidneys for unlimited periods in the absence of ice for later transplantation.