I: Negative effect of cold ischemia on initial renal function

Correlation between post-transplant function and exposure to cold ischemia (CI) during preservation has been reported. We attempted to identify the ef fect of CI on renal function using exsanguinous metabolic support (EMS) tec hnology, to eliminate effects of reperfusion complications. Small bovine ki dneys were used to evaluate 4 vs. 24 hours of CI, after warm ischemic (WI) exposure of <15, 30 or 60 minutes. After CI, kidneys were warm perfused (30 <degrees>C to 32 degreesC) ex vivo using EMS technology. Restored renal met abolism and function were quantified by oxygen consumption, urine productio n, glomerular filtration rate (GFR), and hemodynamic characteristics. The r esults demonstrate a CI-associated lag phase in the restoration of metaboli sm, in which the longer cold-preserved kidneys exhibit a lower initial rate of oxygen consumption. However, after 3 hours of EMS perfusion there was n o significant difference in the O-2 consumed, urine flow, GFR, perfusion fl ow, or pressure between the kidneys stored for 4 or 24 hours. An initial re duction in metabolism after longer CI may influence the severity of actual reperfusion injury during transplantation. Therefore, these results provide preliminary evidence suggesting that an acellular warm temperature reperfu sion ex vivo may enhance restoration of cellular metabolism and minimize da mage from the cold seen upon actual reperfusion.