Evaluation of oxidative stress in the late postoperative stage of liver transplantation.

INTRODUCTION: Liver transplant recipients are at an increased oxidative stress risk due to pre-existing hepatic impairment, ischemia-reperfusion injury, immunosuppression, and functional graft rejection. This study compared the oxidative status of healthy control subjects, patients with liver cirrhosis on the list for transplantation, and subjects already transplanted for at least 12 months. PATIENTS AND METHODS: Sixty adult male patients, aged between 27 and 67 years, were subdivided into 3 groups: a control group (15 healthy volunteers), a cirrhosis group (15 volunteers), and a transplant group (30 volunteers). Oxidative stress was evaluated by activity of reduced glutathione, malondialdehyde, and vitamin E. RESULTS: There was a significant difference (P < .01) in the plasma concentration of reduced glutathione in the 3 groups, with the lowest values observed in the transplanted group. The malondialdehyde values differed significantly (P < .01) among the 3 groups, with the transplanted group again having the lowest concentrations. The lowest concentrations of vitamin E were observed in patients with cirrhosis compared with control subjects, and there was a significant correlation (P < .05) among the 3 groups. No correlations were found between reduced glutathione and vitamin E or between vitamin E and malondialdehyde. However, there were strong correlations between plasma malondialdehyde and reduced glutathione in the 3 groups: control group, r = 0.9972 and P < .0001; cirrhotic group, r = 0.9765 and P < .0001; and transplanted group, r = 0.8981 and P < .0001. CONCLUSIONS: In the late postoperative stage of liver transplantation, oxidative stress persists but in attenuated form.

Should preconditioning hyperbaric oxygenation protect the liver against ischemia-reperfusion injury? An experimental study in a rat model.

OBJECTIVES: We designed studies to test the hypotheses that hyperbaric oxygen (HBO) therapy should protect liver against subsequent ischemia/reperfusion (I/R) injury are scarce and controversial. The purpose of this study was to clarify some questions about the association of HBO with the processes of liver I/R. METHODS: We divided Wistar rats into 5 groups: (1) SHAM operation, (2) I/R, rats submitted to total pedicle ischemia for 30 minutes followed by 5 minutes of reperfusion; (3) HBO60I/R and (4) HBO120I/R, rats respectively submitted to 60 and 120 minutes of HBO therapy at 2 absolute atmospheres and immediately after submitted to the experimental protocol of I/R; (5) HBO120, rats submitted to 120 minutes of HBO therapy at 2 absolute atmospheres and then immediately after humanely killed. The experimental protocol included (1) serum levels of aspartate and alanine aminotransferase; (2) mitochondrial function; (3) tissue malondialdehyde (MDA); and (4) plasma nitrite/nitrate. Data were analyzed using the Mann-Whitney test and were considered significant P < 5%. RESULTS: The processes of liver ischemia/reperfusion caused tissue injury with hepatic mitochondrial functional impairment. A single exposure to 120 minutes of HBO caused an increase of tissue MDA. The time of HBO exposure as preconditioning before hepatic I/R is critical in the prevalence of beneficial or deleterious effects. Sixty minutes of hyperoxic preconditioning before liver I/R presents systemic benefits, but no significant tissue preservation. One hundred twenty minutes of hyperoxic preconditioning tissue liver benefits predominate compared with systemic benefits. CONCLUSIONS: The HBO preconditioning therapeutic benefits to liver I/R injury are time dependent, suggesting a therapeutic window that needs to be clearly defined in future studies.

Comparison of acute physiology and chronic health evaluation II death risk, Child-Pugh, Charlson, and model for end-stage liver disease indexes to predict early mortality after liver transplantation.

OBJECTIVE: This study sought to determine which prognostic index was the most efficient to predict early (1-month) mortality of patients undergoing orthotopic liver transplantation (OLT). MATERIALS AND METHODS: This retrospective study included 63 patients including 49 males and 14 females of overall median age 51.6 ± 9.7 years who were admitted to the intensive care unit (ICU) of a tertiary hospital. The Acute Physiology and Chronic Health Evaluation II (APACHE II) death risk, Child-Pugh, Charlson, and Model for End-stage Liver Disease (MELD) indices pre-OLT and post-OLT were analyzed by generation of receiver operating characteristic (ROC) curves to determine the area under the ROC curve (AUC), as a predictive factor for each index. The level of significance was set at P < .05. RESULTS: The general 1-month posttransplantation mortality rate of OLT patients was 19% (n = 12 p). The AUC was 0.81 (confidence interval [CI] = 0.66-0.96; sensitivity = 72.5; specificity = 83.3) for APACHE II death risk; 0.74 (CI = 0.57-0.92; sensitivity = 76.5; specificity = 66.7) for MELD post-OLT; 0.70 (CI = 0.54-0.85; sensitivity = 64.7; specificity = 66.7) for Child-Pugh; 0.57 (CI = 0.36-0.78; sensitivity = 74.5; specificity = 50.0) for Charlson; and 0.50 (CI = 0.32-0.69; sensitivity = 98.0; specificity = 16.7) for MELD Pre-OLT. CONCLUSION: Among the studied indices, the APACHE II death risk scoring system was the most effective to predict early mortality after OLT.