KIDNEY PRESERVATION AT SUBZERO TEMPERATURES USING A NOVEL STORAGE SOLUTION AND INSECT ICE-BINDING PROTEINS

BACKGROUND: Contemporary kidney preservation methods involve storing at 4 degrees C up to 24 h prior to transplantation. By decreasing the storage temperature to below 0 degrees C, we hypothesized that the safe storage time could be significantly lengthened. OBJECTIVE: The efficacy of a proprietary CryoStasis (CrS) storage solution for the subzero preservation of kidneys was tested, with or without addition of a hyperactive insect antifreeze protein (TmAFP). MATERIALS AND METHODS: Rat kidneys were stored in either University of Wisconsin (UW) solution (4 degrees C, 24 h), CrS (-2 degrees C, 48 h), or CrS with 61.5 mu M TmAFP (-4.4 degrees C, 72 h). Following storage, viability was assessed with MTT reduction assays and live vs. dead cell (FDA/PI) staining. Markers of ischemic damage were analyzed using fluormetric substrates for caspase-3 and calpain activity. RESULTS: Kidneys stored in CrS for 48 h and CrS with TmAFP for 72 h displayed similar levels of enzymatic activity compared to 24 h UW controls. CONCLUSION: This methodology shows promise to prolong the safe storage time of kidneys and offers the potential of increased organ availability for renal transplants.