Factors Associated with Mortality and Graft Failure in Liver Transplants: A Hierarchical Approach

Background

Liver transplantation has received increased attention in the medical field since the 1980s following the introduction of new immunosuppressants and improved surgical techniques. Currently, transplantation is the treatment of choice for patients with end-stage liver disease, and it has been expanded for other indications. Liver transplantation outcomes depend on donor factors, operating conditions, and the disease stage of the recipient. A retrospective cohort was studied to identify mortality and graft failure rates and their associated factors. All adult liver transplants performed in the state of São Paulo, Brazil, between 2006 and 2012 were studied.

Methods and Findings

A hierarchical Poisson multiple regression model was used to analyze factors related to mortality and graft failure in liver transplants. A total of 2,666 patients, 18 years or older, (1,482 males; 1,184 females) were investigated. Outcome variables included mortality and graft failure rates, which were grouped into a single binary variable called negative outcome rate. Additionally, donor clinical, laboratory, intensive care, and organ characteristics and recipient clinical data were analyzed. The mortality rate was 16.2 per 100 person-years (py) (95% CI: 15.1–17.3), and the graft failure rate was 1.8 per 100 py (95% CI: 1.5–2.2). Thus, the negative outcome rate was 18.0 per 100 py (95% CI: 16.9–19.2). The best risk model demonstrated that recipient creatinine ≥ 2.11 mg/dl [RR = 1.80 (95% CI: 1.56–2.08)], total bilirubin ≥ 2.11 mg/dl [RR = 1.48 (95% CI: 1.27–1.72)], Na⁺ ≥ 141.01 mg/dl [RR = 1.70 (95% CI: 1.47–1.97)], RNI ≥ 2.71 [RR = 1.64 (95% CI: 1.41–1.90)], body surface ≥ 1.98 [RR = 0.81 (95% CI: 0.68–0.97)] and donor age ≥ 54 years [RR = 1.28 (95% CI: 1.11–1.48)], male gender [RR = 1.19(95% CI: 1.03–1.37)], dobutamine use [RR = 0.54 (95% CI: 0.36–0.82)] and intubation ≥ 6 days [RR = 1.16 (95% CI: 1.10–1.34)] affected the negative outcome rate.

Conclusions

The current study confirms that both donor and recipient characteristics must be considered in post-transplant outcomes and prognostic scores. Our data demonstrated that recipient characteristics have a greater impact on post-transplant outcomes than donor characteristics. This new concept makes liver transplant teams to rethink about the limits in a MELD allocation system, with many teams competing with each other. The results suggest that although we have some concerns about the donors features, the recipient factors were heaviest predictors for bad outcomes.     

Evaluation of enzyme-linked immunosorbent assay using crude Leishmania and recombinant antigens as a diagnostic marker for canine visceral leishmaniasis

The performances of ELISA assays with different antigen preparations, such as Leishmania amazonensis or L. chagasi lysates and the recombinant antigens rK-39 and rK-26, were compared using sera or eluates from dried blood collected on filter paper to detect anti-Leishmania antibodies in dogs from a visceral leishmaniasis-endemic area in Brazil. Of 115 IFAT-reactive dogs at 1:40 titre, 106 (92.2%) were positive in parasitological exams (skin and/or spleen). These animals were compared to healthy animals (n = 25), negative for IFAT at a titre of 1:40 and parasitological exams. The sensitivities of crude and recombinant antigens were similar and remarkably high for both sera and eluates (97-100%). Specificity was higher than 96% for sera and eluates for different antigens, except for L. chagasi antigen using eluates (88%). Concordance values among the tests were higher either for sera or eluates (J = 0.95-1.00). High concordances were observed between sera and eluates tested with different antigens (kappa = 0.93-0.97). Crude and recombinant antigens identified different clinical phases of canine leishmaniasis. These results show that eluates could be used in canine surveys to identify L. chagasi infection. Recombinant antigens added little when compared to crude antigen in identifying positive dogs. Cross-reactivity with other diseases whose distribution often overlaps VL-endemic areas is a limitation of crude antigen use however.     

The Association between EGFR and cMET Expression and Phosphorylation and Its Prognostic Implication in Patients with Breast Cancer

EGFR and cMET cross-talk is involved in breast cancer (BC) progression and resistance to different targeted therapies, however little is known about the co-expression patterns of EGFR and cMET or its prognostic significance in BC. Protein levels of EGFR, cMET and their phosphorylated proteins were measured in 825 BC samples using reverse phase protein array (RPPA). Given unimodal distribution of proteins, the median was selected as a cut-off after sensitivity analyses. Kaplan-Meier survival curves were used to estimate relapse-free (RFS) and overall survival (OS). Cox-proportional hazards models were utilized to determine associations between EGFR and cMET with outcomes. Mean age was 58 years with 457 (55%) hormone receptor (HR) positive, 211 (26%) triple-negative (TN) and 148 (18%) HER2 positive tumors (HER2+). HER2+ was associated with higher EGFR expression and phosphorylation, compared to HR and TN (p<0.05). High EGFR expression was associated with higher phosphorylated-cMET (p-cMET) but not cMET (ANOVA p-cMET p < 0.001; cMET p = 0.34). The same association was found with high phosphorylated-EGFR (p-EGFR) group at Tyr992 and Tyr1068 (both p < 0.001). High expressions in either of two p-EGFRs were linked with higher cMET as well (all p<0.001). For the TN subtype, high expression in EGFR and p-EGFR at Tyr992 but not at Tyr1068 was associated with higher p-cMET (p<0.00, p = 0.012, p = 0.4 respectively). Only high expression in p-EGFR at Tyr992 was linked with higher expression of cMET (p = 0.02). In contrast, among HER2 subtype, high expression in p-EGFR at Tyr1068 but not at Tyr992 was associated with higher cMET and p-cMET (cMET p = 0.023;p-cMET p<0.001). Four subgroups of patients defined by dichotomized EGFR/p-EGFR and cMET/p-cMET level demonstrated no significant differences in survival. In multivariate analyses, neither cMET nor EGFR expression/activation was found to be an independent prognostic factor in survival outcome.     

IgG and IgM western blot assay for diagnosis of congenital toxoplasmosis

The aim of this study was to evaluate the utility of western blot (WB) analysis as a diagnostic tool for congenital toxoplasmosis in 215 newborn infants. The children were submitted to clinical examinations to assess macular, neurological and hearing signals. The WB results obtained were compared to the persistence of IgG antibodies at the end of 12 months, which is regarded as the "gold standard" diagnosis of congenital toxoplasmosis. Association between the WB results and the clinical signs presented by the infants was also assessed. Of the 215 children, 177 had a confirmed congenital toxoplasmosis diagnosis and 38 were uninfected. IgG-WB showed a sensitivity of 73.5% and a specificity of 97.4%. IgM-WB showed a sensitivity of 54.8% and a specificity of 94.7%. The IgG-WB and IgM-WB combination increased the sensitivity to 86.5%. The IgM-WB-positive children had a 1.4-fold greater risk of presenting active macular lesions than did those that were IgM-WB-negative. This study showed that the WB assay is a useful tool to confirm a diagnosis of congenital toxoplasmosis and that the IgM-WB-positive results can indicate active macular lesions in newborn infants.     

Interaction between artemisinin and heme. A Density Functional Theory study of structures and interaction energies

Malaria is an infectious disease caused by the unicellular parasite Plasmodium sp. Currently, the malaria parasite is becoming resistant to the traditional pharmacological alternatives, which are ineffective. Artemisinin is the most recent advance in the chemotherapy of malaria. Since it has been proven that artemisinin may act on intracellular heme, we have undertaken a systematic study of several interactions and arrangements between artemisinin and heme. Density Functional Theory calculations were employed to calculate interaction energies, electronic states, and geometrical arrangements for the complex between the heme group and artemisinin. The results show that the interaction between the heme group and artemisinin at long distances occurs through a complex where the iron atom of the heme group retains its electronic features, leading to a quintet state as the most stable one. However, for interaction at short distances, due to artemisinin reduction by the heme group, the most stable complex has a septet spin state. These results suggest that a thermodynamically favorable interaction between artemisinin and heme may happen.     

Effect of maternal diet rich in omega‐6 and omega‐9 fatty acids on the liver of LDL receptor‐deficient mouse offspring

BACKGROUND: Omega‐6 fatty acids are important to fetal development. However, during gestation/lactation, these fatty acids may contribute toward the development of fat tissue. Omega‐9 fatty acids are associated with a reduction in serum lipids and protection from liver disease. OBJECTIVES: The present study investigated the effect of the maternal intake of omega‐6 and omega‐9 in hypercholesterolemic mothers on the liver of the offspring. METHODS: LDL receptor–deficient mice were fed a diet rich in either omega‐6 (E6D) or omega‐9 (E9D) for 45 days prior to mating and until the birth of the offspring, evaluating the effect on the offspring liver in comparison to a standard diet (STD). RESULTS: Mothers fed with the E6D experienced an increase in total cholesterol (TC) and the offspring exhibited an increase in TC, hepatic triglycerides (TG), and CC‐chemokine ligand (CCL)2/monocyte chemoattractant protein (MCP)‐1 as well as a reduction in HDL. Histological analysis on this group revealed steatosis, leukocyte infiltrate, and increased CCL2/MCP‐1 expression. The ultrastructural analysis revealed hepatocytes with lipid droplets and myofibroblasts. The offspring of mothers fed the standard diet exhibited low serum TC, but microvesicular steatosis was observed. The offspring of mothers fed the E9D exhibited lower serum and hepatic TG as well as higher LDL in comparison to the other diets. The histological analyses revealed lower steatosis and leukocyte infiltrate. CONCLUSIONS: The findings suggest that hypercholesterolemic mothers with a diet rich in omega‐6 fatty acids predispose their offspring to steatohepatitis, whereas a diet rich in omega‐9 has a protective effect. Birth Defects Res (Part B) 89:164–170, 2010. © 2010 Wiley‐Liss, Inc.     

Molecular analysis of <Emphasis Type="Italic">Aspergillus</Emphasis> section <Emphasis Type="Italic">Flavi</Emphasis> isolated from Brazil nuts

Brazil nuts are an important export market in its main producing countries, including Brazil, Bolivia, and Peru. Approximately 30,000 tons of Brazil nuts are harvested each year. However, substantial nut contamination by Aspergillus section Flavi occurs with subsequent production of aflatoxins. In our study, Aspergillus section Flavi were isolated from Brazil nuts (Bertholletia excelsa), and identified by morphological and molecular means. We obtained 241 isolates from nut samples, 41% positive for aflatoxin production. Eighty-one isolates were selected for molecular investigation. Pairwise genetic distances among isolates and phylogenetic relationships were assessed. The following Aspergillus species were identified: A. flavus, A. caelatus, A. nomius, A. tamarii, A. bombycis, and A. arachidicola. Additionally, molecular profiles indicated a high level of nucleotide variation within β-tubulin and calmodulin gene sequences associated with high genetic divergence from RAPD data. Among the 81 isolates analyzed by molecular means, three of them were phylogenetically distinct from all other isolates representing the six species of section Flavi. A putative novel species was identified based on molecular profiles.     

Cytogenetic divergence in two sympatric fish species of the genus Astyanax Baird and Girard, 1854 (Characiformes,Characidae) from northeastern Brazil

The fish genus Astyanax is widespread throughout the Neotropical region and is one of the most species-rich genera of the Characiformes. Cytogenetic studies of Astyanax have revealed marked intra- and interspecific diversity, with the identification of various species complexes. In this report, we describe the karyotypic structure of two sympatric species of Astyanax (Astyanax sp. and Astyanax aff. fasciatus) from the Middle Contas River basin in the northeastern Brazilian state of Bahia. Both species had 2n = 48 but differed in their karyotypic formulae. Small heterochromatic blocks and multiple nucleolar organizer regions (NORs) were identified in both species. Terminal CMA₃⁺/DAPI⁻ signals were observed in Astyanax sp. and A. aff. fasciatus, mostly coincident with NORs. These results show that chromosomal markers can be used to identify species in this fish complex. These markers can provide useful information for evolutionary studies and investigations on the mechanisms of chromosomal diversity in Astyanax.     

Taurine supplementation increases KATP channel protein content,improving Ca2+ handling and insulin secretion in islets from malnourished mice fed on a high-fat diet

Pancreatic β-cells are highly sensitive to suboptimal or excess nutrients, as occurs in protein-malnutrition and obesity. Taurine (Tau) improves insulin secretion in response to nutrients and depolarizing agents. Here, we assessed the expression and function of Cav and K_ATP channels in islets from malnourished mice fed on a high-fat diet (HFD) and supplemented with Tau. Weaned mice received a normal (C) or a low-protein diet (R) for 6 weeks. Half of each group were fed a HFD for 8 weeks without (CH, RH) or with 5 % Tau since weaning (CHT, RHT). Isolated islets from R mice showed lower insulin release with glucose and depolarizing stimuli. In CH islets, insulin secretion was increased and this was associated with enhanced K_ATP inhibition and Cav activity. RH islets secreted less insulin at high K⁺ concentration and showed enhanced K_ATP activity. Tau supplementation normalized K⁺-induced secretion and enhanced glucose-induced Ca²⁺ influx in RHT islets. R islets presented lower Ca²⁺ influx in response to tolbutamide, and higher protein content and activity of the Kir6.2 subunit of the K_ATP. Tau increased the protein content of the α1.2 subunit of the Cav channels and the SNARE proteins SNAP-25 and Synt-1 in CHT islets, whereas in RHT, Kir6.2 and Synt-1 proteins were increased. In conclusion, impaired islet function in R islets is related to higher content and activity of the K_ATP channels. Tau treatment enhanced RHT islet secretory capacity by improving the protein expression and inhibition of the K_ATP channels and enhancing Synt-1 islet content.