Reperfusion injury in liver transplantation

Reactive metabolites and AGE-RAGE-mediated inflammation in patients following liver transplantation

Recent investigations have indicated that reactive metabolites and AGE-RAGE-mediated inflammation might play an important role in the pathogenesis of ischemia-reperfusion injury in liver transplantation. In this observational clinical study, 150 patients were enrolled following liver transplantation from deceased donors. The occurrence of short-term complications within 10 days of transplantation was documented. Blood samples were collected prior to transplantation, immediately after transplantation, and at consecutive time points, for a total of seven days after transplantation. Plasma levels of methylglyoxal were determined using HPLC, whereas plasma levels of L-arginine, asymmetric dimethylarginine, advanced glycation endproducts-carboxylmethyllysine, soluble receptor for advanced glycation endproducts, and total antioxidant capacity were measured by ELISA. Patients following liver transplantation were shown to suffer from increased RAGE-associated inflammation with an AGE load mainly dependent upon reactive carbonyl species-derived AGEs. In contrast, carboxylmethyllysine-derived AGEs were of a minor importance. As assessed by the ratio of L-arginine/asymmetric dimethylarginine, the bioavailability of nitric oxide was shown to be reduced in hepatic IRI, especially in those patients suffering from perfusion disorders following liver transplantation. For the early identification of patients at high risk of perfusion disorders, the implementation of asymmetric dimethylarginine measurements in routine diagnostics following liver transplantation from deceased donors should be taken into consideration.

Cell death biomarkers as early predictors for hepatic dysfunction in patients after orthotopic liver transplantation

BACKGROUND

Valid prognostic factors for early identification of a complicated course after orthotopic liver transplantation from deceased donors are rare. The aim of this study was to investigate the prognostic value of different cell death biomarkers and inflammatory markers in patients after orthotopic liver transplantation from deceased donors.

METHODS

In total, 100 patients were evaluated for short-term complications within 10 days after orthotopic liver transplantation from deceased donors. Blood samples were collected before surgery, immediately after the end of the surgical procedure, and 1 day and 3, 5, and 7 days later. Plasma levels of total keratin 18, keratin 18 fragments, interleukin 6, tumor necrosis factor α, and soluble intercellular adhesion molecule 1 were measured.

RESULTS

Total keratin 18 was demonstrated to be favorable in its prognostic value for early identification of a complicated course in comparison to routine markers of liver impairment (e.g., aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase). In contrast, inflammation markers (e.g., interleukin 6, tumor necrosis factor α and soluble intercellular adhesion molecule 1) were unsuitable for predicting early complications after liver transplantation from deceased donors.

CONCLUSIONS

For early identification of patients at high risk for complications, the implementation of total keratin 18 measurements in routine diagnostics after orthotopic liver transplantation from deceased donors should be taken into consideration.

Soluble cytokeratin 18 biomarkers may provide information on the type of cell death during early ischemia and reperfusion periods of liver transplantation

Hepatocellular damage takes place as a result of ischemia and reperfusion during liver transplantation (LT). To discriminate the type of cell death and quantitate its severity may provide new insights into the mechanisms of hepatocellular damage. Therefore, we investigated the type of cell death by ELISA-based assays in patient sera. Apoptosis was specifically assessed by measuring a novel soluble biomarker, the caspase-cleaved cytokeratin 18, while total cell death (apoptosis and necrosis) by cytokeratin 18 released from dead (necrotic and apoptotic) cells. Twenty-seven live (LDLT) and 14 deceased (DDLT) donor liver transplantations were analyzed before the operation, at the anhepatic stage, first, sixth and 24th hour after the reperfusion. Both apoptosis and total cell death have successfully been demonstrated although they have not been confirmed by the liver biopsy that is impossible to perform in this setting. Apoptosis was not induced in LDLT. Total cell death (primarily necrosis) only transiently appeared the first hour after the reperfusion in LDLT, while it sharply increased the first hour after the reperfusion and maintained its level in DDLT. Soluble cytokeratin 18 biomarkers seem to be useful to discriminate and quantitate the type of cell death during early ischemia and reperfusion periods of LT.

Intrahepatic cholestasis after liver transplantation

Biochemical cholestasis after liver transplantation is common and often has no clinical significance if biliary anastomosis strictures and leaks have been excluded. There is no agreed upon definition for severe cholestasis, but it is associated with a worse mortality. There has been little evaluation on risk factors, but these include cryoprecipitate and platelet transfusion intraoperatively, nonidentical blood group, suboptimal graft appearance, inpatient status before transplant, and bacteremia within the first month. Associated causes considered as early (<6 months) include ischemia-reperfusion injury, primary nonfunction, small-for-size graft syndrome, infection, drugs and acute cellular rejection. Late causes include hepatic artery thrombosis, chronic rejection, biliary complications, recurrent viral and cholestatic disease, and posttransplant lymphoproliferative disorder.