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Relevance of proteolysis and proteasome activation in fatty liver graft preservation: An Institut Georges Lopez-1 vs University of Wisconsin appraisal.

ABSTRACT: To compare liver proteolysis and proteasome activation in steatotic liver grafts conserved in University of Wisconsin (UW) and Institut Georges Lopez-1 (IGL-1) solutions.Fatty liver grafts from male obese Zücker rats were conserved in UW and IGL-1 solutions for 24 h at 4 °Cand subjected to "ex vivo" normo-thermic perfusion (2 h; 37 °C). Liver proteolysis in tissue specimens and perfusate was measured by reverse-phase high performance liquid chromatography. Total free amino acid release was correlated with the activation of the ubiquitin proteasome system (UPS: measured as chymotryptic-like activity and 20S and 19S proteasome), the prevention of liver injury (transaminases), mitochondrial injury (confocal microscopy) and inflammation markers (TNF 1 alpha, high mobility group box-1 (HGMB-1) and PPAR gamma), and liver apoptosis (TUNEL assay, cytochrome c and caspase 3).Profiles of free AA (alanine, proline, leucine, isoleucine, methionine, lysine, ornithine, and threonine, among others) were similar for tissue and reperfusion effluent. In all cases, the IGL-1 solution showed a significantly higher prevention of proteolysis than UW (P < 0.05) after cold ischemia reperfusion. Livers conserved in IGL-1 presented more effective prevention of ATP-breakdown and more inhibition of UPS activity (measured as chymotryptic-like activity). In addition, the prevention of liver proteolysis and UPS activation correlated with the prevention of liver injury (AST/ALT) and mitochondrial damage (revealed by confocal microscopy findings) as well as with the prevention of inflammatory markers (TNF1alpha and HMGB) after reperfusion. In addition, the liver grafts preserved in IGL-1 showed a significant decrease in liver apoptosis, as shown by TUNEL assay and the reduction of cytochrome c, caspase 3 and P62 levels.Our comparison of these two preservation solutions suggests that IGL-1 helps to prevent ATP breakdown more effectively than UW and subsequently achieves a higher UPS inhibition and reduced liver proteolysis.

SUBMITTER: Zaouali MA

PROVIDER: S-EPMC5483495 | biostudies-other | 2017 Jun

REPOSITORIES: biostudies-other

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Project description:BackgroundThe question of whether the choice of preservation solution affects outcome after liver transplantation is still not satisfactorily answered. The purpose of this study is to examine the preservation solutions' impact on outcome after liver transplantation.MethodsA double-center retrospective study of short- and long-term results of 3134 consecutive liver transplantations with follow-up periods up to 23 years was performed applying multivariate, risk-adjusted analyses with a subset for living-donor transplants, pediatric transplants and cases with prolonged cold ischemic times. An additional focus was put on biliary complications. The primary study endpoints were short- and long-term patient survival and death-censored graft survival. Secondary study endpoints were the occurrence of post-transplant complications, the necessity of operative revisions, the length of hospital stay, and the length of intensive care unit stay.ResultsAlthough long-term graft survival appears to be increased by Histidine-Tryptophan-Ketoglutarate-use (p = 0.018), this effect could not be confirmed in risk-adjusted analysis (p = 0.641). Multivariate regression analysis revealed that 3-month mortality (p = 0.120), 3-month graft survival (p = 0.103) and long-term patient survival (p = 0.235) were not influenced by the choice of preservation solution. There was no difference in the occurrence of common complications or necessity of operative revisions after liver transplantation. This was confirmed in subgroup analyses for living donor and pediatric transplantation and cases with prolonged cold ischemic time. Analysis of the preservation solutions' impact on length of hospital (p = 0.113) and intensive care unit stay (p = 0.481) revealed no significant difference.ConclusionsUniversity of Wisconsin and Histidine-Tryptophan-Ketoglutarate solutions are clinically equivalent. Histidine-Tryptophan-Ketoglutarate solution could have an economically superior profile. The notion that the choice of preservation solution can have an impact on the onset of biliary complications after liver transplantation remains a matter of controversy.

Project description:To compare Institut Georges Lopez (IGL-1) and Celsior preservation solutions for hepatic endothelium relaxation and liver cold ischemia reperfusion injury (IRI).Two experimental models were used. In the first one, acetylcholine-induced endothelium-dependent relaxation (EDR) was measured in isolated ring preparations of rat hepatic arteries preserved or not in IGL-1 or Celsior solutions (24 h at 4 °C). To determine nitric oxide (NO) and cyclooxygenase EDR, hepatic arteries were incubated with L-NG-nitroarginine methyl ester (L-NAME), an inhibitor of endothelium nitric oxide synthase (eNOS), or with L-NAME plus indomethacin, an inhibitor of cyclooxygenase. In the second experiment, rat livers were cold-stored in IGL-1 or Celsior solutions for 24 h at 4 °C and then perfused "ex vivo" for 2 h at 37 °C. Liver injury was assessed by transaminase measurements, liver function by bile production and bromosulfophthalein clearance, oxidative stress by malondialdehyde levels and catalase activity and alterations in cell signaling pathways by pAkt, pAMPK, eNOS and MAPKs proteins level.After cold storage for 24 h with either Celsior or IGL-1, EDR was only slightly altered. In freshly isolated arteries, EDR was exclusively mediated by NO. However, cold-stored arteries showed NO- and COX-dependent relaxation. The decrease in NO-dependent relaxation after cold storage was significantly more marked with Celsior. The second study indicated that IGL-1 solution obtained better liver preservation and protection against IRI than Celsior. Liver injury was reduced, function was improved and there was less oxidative stress. IGL-1 solution activated Akt and AMPK, which was concomitant with increased eNOS expression and nitrite/nitrate levels. Furthermore, MAPKs kinases were regulated in livers preserved with IGL-1 solution since reductions in p-p38, p-ERK and p-JNK protein levels were observed.IGL-1 solution preserved NO-dependent relaxation better than Celsior storage solution and enhanced liver graft preservation.

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Relevance of proteolysis and proteasome activation in fatty liver graft preservation: An Institut Georges Lopez-1 vs University of Wisconsin appraisal.

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