OPTIMAL PH FOR SIMPLE COLD-STORAGE OR MACHINE PERFUSION OF DOG KIDNEYS WITH UW SOLUTION

Metabolic suppression by temperature is a key to successful organ pres ervation. additional methods for inducing metabolic suppression may fu rther improve organ preservation. Extracellular acidosis has been show n to suppress warm anoxic injury to various isolated cells. Acidosis m ay suppress enzymes with a pH optimum at the pH of the cytosol (pH 7.3 ). In this study, the combination of hypothermia and acidosis was used to determine if it would improve renal preservation. Dog kidneys were cold-stored (CS) for 48 h in University of Wisconsin (UW) solution wi th the pH adjusted to 6.4, 6.8, 7.4, or 7.8. Kidneys were also machine -perfused (MP) for 3 days with the gluconate perfusion solution (Belze r's machine perfusion solution, MPS) at pHs similar to those tested fo r CS. Renal function (serum creatinine, SCr) and survival were recorde d in immediate contralateral nephrectomized recipients. On the basis o f maximum SCr values, kidneys preserved by CS or MP were best preserve d at pHs of 7.4 or 7.8. At a pH of 6.8, SCr values were elevated and r eturned to normal at a slower rate than in those preserved at higher p Hs. This study shows that acidosis is not cytoprotective to cold-store d dog kidneys and causes preservation/reperfusion injury.