Study of gene expression profile in liver transplant recipients with hepatitis C virus.

The main objective of this study was to identify differences in gene expression profiles by liver transplant recipients with hepatitis C virus (HCV) using microarray technology before versus after liver transplantation. The study was performed in liver transplant recipients with HCV (n = 6) versus a group of healthy volunteers (n = 6). Peripheral blood samples were obtained before (T0) and 7 days after liver transplantation (T7d) using tubes with an RNA stabilizer. The quality of purified RNA was tested (28S/18S ratio >1.5) in a bioanalyzer. Each participant in the study underwent microarrays in duplicate using 10 mug of complementary RNA. After reverse transcription, cRNAs were labeled with Cy5 Streptavidine. Hybridization of 20000 human genes CodeLink bioarrays (Applied Microarrays, United States) was performed overnight at 37 degrees C. Arrays read with a laser scanner were normalized with CodeLink Software 4.2. At T0, liver transplant recipients showed 116 over-expressed genes when compared with healthy volunteers, who had 33 genes increased >2-fold (P < .05). At T7d after transplantation, the same group of patients showed 613 over-expressed genes compared with T0, of which 97 genes were increased >2-fold (P < .05). We determined gene expression profiles in peripheral blood samples obtained before and after liver transplantation, reporting the array of gene expression profiles in peripheral blood samples from each of these patients classes. One implication of these results is that gene profiling of peripheral blood samples could be used to dynamically monitor the impact and adequacy of immunosuppression in individual patients using microarray technology.

Early postoperative response of cytokines in liver transplant recipients.

We evaluated the early postoperative response of several cytokines (IL-2, IL-4, IL-6, IL-10, TNF-alpha, IFN-gamma) prior to liver transplantation (T(0)) as well as 1, 6, and 12 hours and 1, 2, 3, 5, and 7 days afterward. Cytokine concentrations were correlated with serum levels of bilirubin as a predictor of postoperative complications. Cytokine levels were determined in plasma samples from 16 liver transplant recipients (13 men, 3 women) aged 43 to 61 years. IL-6 and IL-10 reached their maximum concentrations 1 hour after transplantation. Each increase in IL-6 correlated to a rise in IL-10. IL-2, IL-4, TNF-alpha, and IFN-gamma had a particular time-course for each patient studied. Bilirubin fell to almost normal values but not in cases of postoperative complications, where IL-6 showed values four times higher compared to those of liver transplant recipients who did not show postoperative complications. IL-6 and IL-10 plasma concentrations and serum bilirubin level might be useful as a predictive factor of postoperative complications in liver transplant recipients.

Influence of Obesity on Liver Transplantation Outcomes.

OBJECTIVE: The aim of this work was to determine the impact of obesity on the morbidity and mortality of liver transplantation (LT) recipients. METHODS: A single-center, observational-cohort, retrospective study was conducted in patients undergoing LT from January 2008 to December 2014 to compare complications and survival between those with body mass index (BMI) <35 kg/m2 and those with BMI ≥35 kg/m2. RESULTS: The study included 170 patients: 162 (95.3%) with BMI <35 kg/m2 and 8 (4.7%) with BMI ≥35 kg/m2. The groups significantly differed in overall mortality and graft survival: The risk of death was 3.54-fold higher (95% confidence interval, 1.39-9.03) and the mean graft survival was shorter (61 vs 21 mo; P = .001) in the group with BMI ≥35 kg/m2. The groups did not significantly differ in rates of biliary complications, arterial and portal vein thrombosis, retransplantation or reintervention, intraoperative requirement for blood products, length of intensive care unit stay, or post-reperfusion syndrome or rejection rates. CONCLUSIONS: Although no significant differences were found between these groups in post-transplantation complications, BMI ≥35 kg/m2 emerged as a mortality risk factor in these patients.

Time course of antioxidant enzyme activities in liver transplant recipients.

Reactive oxygen species (ROS) play a central role in ischemia-reperfusion injury after organ transplantation. They are degraded by endogenous radical scavengers such as antioxidant enzymes. The purpose of this study was to evaluate the temporal variations of antioxidant enzyme activities in liver transplant recipients. The study was performed in 13 liver transplant patients (11 men and 2 women). Blood samples were obtained pre- and postsurgical intervention: before transplant (T(0)), and 1, 6, 12, 24, 48, and 72 hours, as well as 5 and 7 days thereafter. We determined total and specific superoxide dismutase (SOD) activity, catalase (CAT), glutathione peroxidase (GPX), and glutathione reductase (GR) activities as well as malondialdehyde (MDA) and low-density lipoproteins (LDL). The results showed increased SOD and mainly GPX activities after liver transplantation, which correlated with MDA levels. Total SOD activity was mainly represented by Mn-SOD (75%) and Cu,Zn-SOD (25%), whereas Fe-SOD was not detected. In conclusion, the enhanced antioxidant enzyme activities reported in this study indicated a control of oxidative stress generated in liver transplantation. In this sense, although MDA levels showed an enormeous increase at 1 hour after transplantation, the lipid peroxidation was compensated for by GPX activity.

Nonlinear optical waveguides generated in lithium niobate by swift-ion irradiation at ultralow fluences.

A novel method to produce optical waveguides is demonstrated for lithium niobate (LiNbO(3)). It is based on electronic excitation damage by swift ions, i.e., with energies at approximately 1 MeV/amu or above. The new technique uses high-energy medium-mass ions, such as Cl, with electronic stopping powers above the threshold value for amorphization (5-6 keV/nm), reaching the maximum value a few micrometers inside the crystal. At the ultralow fluence regime (10(12)-10(13) cm(-2)) an effective nanostructured medium is obtained that behaves as an optical waveguide where light propagates transversally to the amorphous nanotracks created by every single impact. The method implies a reduction of 4 orders of magnitude with respect to He implantation. The optical waveguides present reasonable losses (~10 dB/cm) and significant second-harmonic generation (SHG) and electro-optic (EO) responses (>50% bulk) for the lowest fluences.