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

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. Rabbit kidneys were perfused with VS4 according to three different protocols. The kidneys were evaluated using an autograft model with immediate contralateral nephrectomy. 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. 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.