Role Of Normothermic Machine Perfusion In Perserving Pig Livers Of DCD And Its Influence On Bile Duct

Objective: Liver transplantation is the effective method of treatment for end stage liver disease patients, but availability of liver grafts is still the main limitation to its wider use.The need for more safe donor grafts made us pay more attention to reaserching of DCD grafts.UW cold storage is regarded as the standard organ preservation protocol,but could not fulfill the needs of clinical practice in the DCD organ. Normothermic machine perfusion preserves under normothermic conditions,the liver reaches simulate physiological metabolic rate and functionality.In this study,we subject to establish a stable,practical NMP system,as well as to evaluate the effect and its mechanism of NMP in reducing the bile duct injury in donation after cardiac death.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 bile ducts, as well as the bile production through NMP preservation of the donor livers drived from 6 Bama miniature pigs. 2.12 Bama miniature donor pigs underwent 40-minnute cardiac arrest and were randomly allocated to two groups.In the NMP group,donor livers underwent 6-hour NMP preservation.In the UW group,livers were preserved with 4? UW solution for 6hours.Then liver transplantation was performed in both groups. The serum biochemical markers,the pathological changes and Immunohistochemistry were compared these two groups.Results: 1.The NMP equipment was successfully constructed.During the whole course of NMP preservation,the temperature, the pressure and the flow of ALT,AST,LDH,ALP,Lac in the perfusion fluid slightly elevated at the beginning, and then maintained at stable level. The total bile production was 27.6±0.59 ml. The semiquantitative scores of biliary injury showed a statistically significant difference between the UW and NMP groups(12?10?9?8?7?10)VS(6?8?7?7?5?9)(P<0.05).2.The survival rate between NMP group and UW group was 100% and 0respectively. The level of serum ALT, ALT, LDH and Lac in the NMP group was lower than those in the UW group(P<0.05). Pathological examination also show the bile duct injury in the NMP group was lighter than it in the UW group.Diffuse Ki-67 staining was present throughout the biliary epithetlium and PBGs of the NMP-preserved livers, and this indicated recent cell proliferation. Conversely,Ki-67 staining was virtually absent in the bile ducts and PBGs of the UW group.Immunohistological stains for v WF demonstrated increased platelet aggregates inthe peribiliary capillary plexus of the UW group versus the NMP group.Conclusion: 1.NMP can reverse the energy deficient after warmischemia, through providing continuous oxygen and nutrients has a good protective effect on the donor organ. 2 Using the NMP equipment requires the organ after warm ischemic, the longer time should be maintain when meet an organ with a longer warm ischemic time. 3 Achieving protection or improved recovery of these critical components of the bile duct wall by machine perfusion could therefore contribute to the prevention of NAS. Here, preventing injury altogether would be the ultimate target, because when regeneration is not needed it also cannot fail. If this cannot be accomplished,protection of the PVP and PBG to facilitate successful regeneration through tissue oxygenation and preservation of progenitor cells in the PBG are obvious subsidiary goals.4. NMP could transform the injury sequence(WI-cold ischemia- SWIT- WI postreperfusion hypoperfusion) into ischemic preconditioning(WI-oxygenated NMP– SWIT- graft reperfusion) and eliminate 2 of the 3 ischemic biliary hits.