Normothermic Machine Perfusionreduces Ischemic Reperfusion Injury Of DCD Liver Grafts In Pig Liver Transplantation

Objective:The shortage in donor livers has led to increase using of DCD grafts.Increasing incidence of PNF,DGF and ITBL as well as lower graft survival rate are seen in recipients of DCD liver transplantation.Cold preservation could not fulfill the needs of clinical practice in liver transplantation.NMP storage could significantly alleviate the ischemia reperfusion injury of DCD liver grafts.In this study,we subject to establish a stable,practical NMP system,as well as to investigate the effect and its mechanism of NMP in alleviating the ischemia reperfusion injury of DCD grafts.Methods:1.NMP system was established with centrifugal,oxygenator,thermostatic incubator,connecting pipes,and etc.We investigate the pressure and flow of the portal vein and hepatic artery,temperature,biochemical markers in the perfusion fluid,pathological changes of the donor liver,as well as the bile production through ex vivo NMP preservation of the donor livers derived from 4 Bama miniature pigs.2.Pig liver transplant model without veno-venous bypass was developed using30 healthy Bama miniature pigs.The intraoperative hemodynamic changes,parameters of arterial blood gas,postoperative survival rate and the incidence of postoperative complications weremonitored.3.24 Bama miniature donor pigs underwent 40-minute cardiac arrest and were randomly allocated to two groups.In the group A,donor livers underwent 6-hour NMP preservation.In the group B,livers were preserved immediately with 4℃UW solution for 6 hours.Liver transplantation without by-pass was performed in both groups.The survival rate,the serum biochemical markers,the histopathological changes of the donor livers,as well as the expression of cytokines in the livers were compared between these two groups.Results:1.The NMP equipment was successfully constructed.During the whole course of NMP preservation to the pig donor livers,the temperature,the pressure and blood flow of portal vein and hepatic artery were stable.The levels of ALT,AST,LDH,ALP,lactic Acidin the perfusion fluid slightly elevatedat the beginning of NMP,and then maintained at stable level.The average bile production was 10.3±3.61ml/h.The pathological examination demonstrated that the histological structure of the donor livers was normal after 6-hour preservation.2.After early period of technical training,the 5d survival rate of the recipient pigs was 100%,and no surgical complications were occurred.Obvious decreasing of the CVP,MAP and increasing of the heart rate was observed during the anhepatic phase.Significant depressing of the pH,HCO₃^-and BE level in arterial blood was found by the time of portal vein was reperfused.3.The 5d survival rate in group A and B was 100%and 0 respectively.After 40-minutes warm ischemia and 6-hours storage,the level of ATP,SOD and HSP-70 in the liver tissue of group A was higher than those of group B（p<0.05）,while the content of TNF-ɑ,ROS,BCL-2,ET-1 and ICAM-1 in the liver tissue of group A was lower than those of group B（p<0.05）.After reperfusion,the level of SOD and HSP-70 in the liver tissue of group A was higher than those of group B（p<0.05）,the content of TNF-ɑ,IL-1,ROS,BCL-2,ET-1 and ICM-1 was lower than those of group B（p<0.05）,the level of serum ALT,AST,LDH and Lactic acid in group A was lower than those in group B（p<0.05）.The pathological examination of the donor liver demonstrated that the injury of the hepatocytes in group A was slighter than that in group B after 6-hour preservation and reperfusion.Conclusion:1.The NMP equipment was successfully constructed.There was also no obvious injury to the liver tissue during the NMP preservation of the miniature pig DCD livers.2.Pig liver transplant without veno-venous bypass model was successfully developed,and the successful rate of operation was 100%with good stability and repeatability through technical training.To shorten the anhepatic phase and optimize the perioperative management especially during the anhepatic phase was important to perform successful pig liver transplantation without veno-venous bypass.3.NMP storage could significantly alleviate the ischemia reperfusion injury of pig DCD livers followed by improving the prognosis of liver transplantation.Its mechanism was that NMP could mimic the physiological environment of organs,maintain the cellular metabolism,reverse the injury caused by discontinuity of ATP supplying during the course of warm ischemia,avoid the injury to the sinusoidal endothelial cells due to hypothermia,increase the expression of protected protein and reduce the expression of inflammatory cytokines after preservation and reperfusion.