EXTRACELLULAR HTK PERFUSION AND INTRACELLULAR ACIDIFICATION IN ISCHEMIC DOG KIDNEYS - A P-31 NMR SPECTROSCOPIC STUDY

Purpose: Bretschneider's histidine-tryptophan-ketoglutarate solution ( HTK) for organ preservation is in wide clinical use. Its high bufferin g capacity is its major protective principle. It is assumed that renal ischemic tolerance benefits from this principle. The study was undert aken to determine the degree to which extracellular buffering influenc es intracellular acid load. Material and Methods: Canine kidneys were investigated for intracellular and extracellular pH changes during a c linically relevant period of ischemia after preperfusion with either H TK or Ringer solution (Ringer) at different temperatures. Extracellula r pH (pH(e)) was measured with ion-sensitive electrodes. Intracellular pH (pH(i)) was determined with P-31 NMRS. Morphologic and functional parameters were assessed in reperfusion experiments. Results: After pe rfusion with HTK, pH(e) values of 7.35, 7.25, and 7.30 were determined for 5C, 20C and, normothermia, respectively. The pH(e) values after 1 50 minutes were 7.37, 6.84, and 6.76 at the temperatures indicated. Th e corresponding pH(i) values 150 minutes after HTK perfusion were 7.20 , 6.79 and 6.54. After Ringer perfusion and 150 minutes at 20C and nor mothermia, pH(i) values of 6.29 and 5.92 were measured. Reperfusion ex periments showed better results in the HTK group. Conclusions: Preperf usion with HTK considerably decreases ischemic acidification of extrac ellular and intracellular compartments at 20C and 37C, compared with R inger. In kidneys preperfused with HTK and kept at 5C, a nearly physio logic pH was maintained during the observation period of 150 minutes a nd longer, HTK leads to better functional and morphologic preservation compared to Ringer.