DISCRIMINANT QUANTITATION OF POSTTRANSPLANT HEPATIC RETICULOENDOTHELIAL FUNCTION - THE IMPACT OF ISCHEMIC PRESERVATION

This study focuses upon two discrete components of posttransplant hepa tic reticuloendothelial system (RES) function-phagocytosis and killing of bacteria-under various conditions of ischemic preservation, We had previously reported that, following intravenous injection of rats wit h Cr-51 and I-125 double-labeled Escherichia cell, hepatic Cr-51 level s can be used to reliably quantify hepatic phagocytic clearance of the bacteria from the blood (HPC), while the subsequent release of I-125 from the Liver accurately parallels hepatic bacterial killing, Here, W istar rats were transplanted with syngeneic livers perfused with eithe r normal saline CNS) or University of Wisconsin solution (UW) and stor ed at 4 degrees C for 1, 2, or 3 hr prior to implantation, Control rat s underwent laparotomy and hepatic artery ligation, Using the double-l abeled E coli assay, HPC was decreased in all transplanted animals whe n compared with controls, reaching a nadir on the third postoperative day (P<0.05), In rats transplanted with livers preserved in NS, the fr action of phagocytosed organisms that were subsequently killed (hepati c killing efficiency=HKE) was increased to 142%, 129%, or 112% of norm al following 1, 2, or 3 hr of cold ischemia, respectively; P<0.05). Co nversely, preservation of donor allografts in UW was associated with m arked depression of HKE. Moreover, rats receiving NS- or UW-preserved livers tolerated an intravenous challenge with Streptococcus pneumonia e poorly (50% mortality) compared with hepatic artery ligated controls (12% mortality) at 7 days. Ischemic preservation of rat Livers in NS resulted in a dose (of ischemia)-dependent reduction of hepatic phagoc ytosis coupled with a potentiation of HKE, Preservation in UW, however , produced a striking suppression of both components of hepatic RES fu nction, Following a septic challenge survival was reduced in both grou ps of transplanted rats.