0041-1337/02/7312-1869/0 TRANSPLANTATION Vol. 73, 1869–1874, No. 12, June 27, 2002 Copyright © 2002 by Lippincott Williams & Wilkins, Inc. Printed in U.S.A. IMPROVING THE QUALITY OF KIDNEYS FROM NON-HEART- BEATING DONORS, USING STREPTOKINASE: AN ANIMAL MODEL 1 MUHAMMED A. GOK, 2,7 BRIAN K. SHENTON, 2 ROBERT PEASTON, 3 CHRIS CORNELL, 3 HELEN ROBERTSON, 4 MARIE MATHERS, 4 JONATHAN D. AITCHISON, 5 JOHN H. DARK, 5 DAVE MANTLE, 6 AND DAVID TALBOT 2 Department of Surgery, The Medical School, Newcastle University, Newcastle Upon Tyne; Department of Biochemistry, The Freeman Hospital, Newcastle Upon Tyne; Department of Pathology, University of Newcastle; Cardiothoracic Transplant Unit, The Freeman Hospital, Newcastle Upon Tyne; Department of Agriculture and Environmental Science, Newcastle University, Newcastle Upon Tyne, UK Background. Non-heart-beating donors (NHBD) of- fer a promising potential to increase the cadaveric organ donor pool, especially for kidneys. However, almost half of NHBD kidneys are discarded after viability assessment. This wastage is costly in both human and monetary terms. Intravascular thrombo- sis at the time of donor death is an event leading to failure in the viability assessment. We have devel- oped an animal model to investigate the effects of the addition of streptokinase to the in situ flush medium before transplant in an attempt to redress the situation. Methods. Two groups of eight healthy young Land- race Yorkshire white pigs were entered into the study. Both groups were subjected to approximately 70 min warm ischemia. Both groups received an intravascu- lar flush with 4 L of Marshall’s solution with heparin (1000 IU/L); one group of pigs also had streptokinase (1.5 MIU/L) added. After donor nephrectomy, all kid- neys were machine perfused for 4 hr. Data on perfu- sion characteristics were taken and samples of kidney effluent were assayed for tissue damage biomarkers, glutathione S-transferase (GST) and alanine amino- peptidase (Ala-AP). Wedge sections of porcine kidneys were taken at the end of perfusion, for histological analysis. Results. Data on machine perfusion parameters (temperature, mean pressure index, resistance) indi- cate better cooling, lower resistance, and lower mean pressure index in the streptokinase-treated group of pigs. GST and Ala-AP levels were increased in the nonstreptokinase group perfusates. Histopathological analysis of porcine kidneys indicated more ischemic injury and tissue damage in the nonstreptokinase group. Conclusion. The use of streptokinase in this porcine NHBD model conferred benefits to donor kidneys when assessed by machine perfusion. Markers of bio- chemical injury indicated that less renal tissue dam- age occurred with the incorporation of streptokinase in the in situ flush medium. INTRODUCTION As the number of transplantable kidneys from traditional brainstem-dead donor sources has reached a plateau in re- cent times, there has been a renewed interest in sourcing kidneys from non-heart beating donors (NHBD) (1). Optimis- tic estimates have predicted a potential increase of 20 – 45% in the kidney donor pool with the wide scale implementation of a NHBD program (2, 3). However, two problems are en- countered by established NHBD centers. First, not all kid- neys harvested are transplanted and second, some kidneys that are transplanted do not function. A variable rate of 9 –35% of harvested NHBD kidneys has been reported for discarded kidneys after viability assessment (4–7). Primary nonfunction (PNF) has been reported to develop in 6 –11% of NHBD renal transplants. In our own center, (33.3%) 1:3 and (100%) 1:1 Maastricht category II and III NHBD kidneys, respectively, are subsequently transplanted, with an overall PNF rate of 10.3%. Warm ischemic injury is a crucial factor in the causation of tissue damage during organ procurement. Viability assess- ment is therefore important in preventing PNF. Rejection of kidneys is therefore inevitable, which is costly in monetary and human terms. Donor pretreatment procedures have been associated with improvement in the quality of kidney allo- graft; e.g., use of in situ (intravascular and intraperitoneal) cooling, continued donor resuscitation after pronouncement of death (e.g., mechanical thumper), machine preservation of NHBD kidneys, use of different preservation solutions, and vitamin supplemented donors (8 –10). It is generally accepted that machine-perfused kidneys perform better than cold-stored kidneys in terms of survival and graft function (8). This has lead to the universal deploy- ment of machine preservation of all NHBD kidneys. In addi- tion to allograft resuscitation, machine preservation enables allograft assessment, via review of perfusion and enzyme characteristics. Cardiac arrest is followed by stasis of blood and then in- travascular thrombosis. This phenomenon becomes crucial in viability assessment of NHBD kidneys. Our objective was to investigate the use of streptokinase to reverse this intravas- cular thrombosis in a porcine NHBD model, to evaluate the effect on machine perfusion (MP) characteristics and kidney 1 Supported by the Northern Counties Kidney Research fund and the Freeman Hospital. 2 Department of Surgery, The Medical School, Newcastle University. 3 Department of Biochemistry, The Freeman Hospital. 4 Department of Pathology, University of Newcastle. 5 Cardiothoracic Transplant Unit, The Freeman Hospital. 6 Department of Agriculture and Environmental Science, New- castle University. 7 Address correspondence to: M. A. Gok, F.R.C.S., Renal and Liver Transplant Unit, The Freeman Hospital, High Heaton, Newcastle Upon Tyne, NE7 7DN, England, UK. 1869