Enhanced resistance to the effects of hypothermic ischemia in the preserved canine kidney.

Addition of trifluoperazine (TFP), a powerful calmodulin inhibitor to Collins' flush solution has exerted a significant protective effect on the cold-preserved kidney, with successful autotransplantation of 80% of preserved kidneys (4 of 5) after 72 hr of storage. In contrast, use of Collins' solution alone resulted in successful autotransplantation of only 33% (2 of 6) of kidneys after a similar period of preservation. In an attempt to analyze the significance of this result, the microcirculation of preserved kidneys was studied with injections of technetium-labeled microspheres into the kidneys, followed by study with a noninvasive radionuclide scintiphotography (RNS) technique that does not interfere with subsequent transplantation of the kidney. Such studies demonstrate that prolonged cold preservation after flush-cooling with Collins' solution is associated with a progressive deterioration of the integrity of the microcirculation, resulting in poor flow to the renal cortex. In contrast, when TFP is added to the Collins' solution, there are uniform increases in renal cortical flow in kidneys stored for 48 and 72 hr, with preservation of the integrity of the renal microcirculation. Biological testing shows a clear-cut correlation between these observations and the capacity of the tested kidneys to sustain life after retransplantation. Further experiments suggest that the decreases observed in cortical flow in kidneys preserved in the cold for 72 hr are a consequence of cellular swelling, and not of a vasospastic response. The data support the conclusion that TFP exerts its protective effect on the basis of its membrane stabilizing capacity as a calmodulin inhibitor, and not through direct vasodilatation.