Background & Aims Acute-on-chronic liver failure (ACLF) is a frequent syndrome (30% prevalence), characterized by acute decompensation of cirrhosis, organ failure(s) and high short-term mortality. ...This study develops and validates a specific prognostic score for ACLF patients. Methods Data from 1349 patients included in the CANONIC study were used. First, a simplified organ function scoring system (CLIF Consortium Organ Failure score, CLIF-C OFs) was developed to diagnose ACLF using data from all patients. Subsequently, in 275 patients with ACLF, CLIF-C OFs and two other independent predictors of mortality (age and white blood cell count) were combined to develop a specific prognostic score for ACLF (CLIF Consortium ACLF score CLIF-C ACLFs). A concordance index (C-index) was used to compare the discrimination abilities of CLIF-C ACLF, MELD, MELD-sodium (MELD-Na), and Child-Pugh (CPs) scores. The CLIF-C ACLFs was validated in an external cohort and assessed for sequential use. Results The CLIF-C ACLFs showed a significantly higher predictive accuracy than MELDs, MELD-Nas, and CPs, reducing (19–28%) the corresponding prediction error rates at all main time points after ACLF diagnosis (28, 90, 180, and 365 days) in both the CANONIC and the external validation cohort. CLIF-C ACLFs computed at 48 h, 3–7 days, and 8–15 days after ACLF diagnosis predicted the 28-day mortality significantly better than at diagnosis. Conclusions The CLIF-C ACLFs at ACLF diagnosis is superior to the MELDs and MELD-Nas in predicting mortality. The CLIF-C ACLFs is a clinically relevant, validated scoring system that can be used sequentially to stratify the risk of mortality in ACLF patients.
Background
Adenoma and polyp detection rates (ADR and PDR, respectively) are important indicators of endoscopy quality, particularly in colorectal carcinoma screening.
Objective
To assess the ...influence of the endoscopist's experience on the ADR and PDR.
Patients and Methods
In this study, 9635 colonoscopies were screened during a 5‐year period. Only 5738 were finally analyzed due to exclusion criteria. The endoscopists were separated in three groups of experience according to the number of colonoscopies performed in the past (yearly and total). The number of polyps and adenomas, as well as the size and histology of these polyps were recorded.
Results
The ADR and PDR were similar regardless of the experience of the endoscopist, but those with more experience clearly found more polyps of less than 10 mm (P = 0.01) and of less than 3 mm (P < 0.0001). Most of the differences were due to a higher number of flat polyps detected by the experienced group. This study also shows that more experienced endoscopists detect adenomas with more advanced histology (P < 0.0001).
Conclusion
Even though the ADR and PDR are similar in all groups of endoscopists, the less experienced endoscopists could be missing some of the smaller polyps, sometimes with more advanced histology.
Summary
Background and Aims
Little is known about the extent of mitochondrial respiratory chain (MRC) activity dysfunction in patients with alcoholic hepatitis (AH). We aimed to assess the hepatic ...MRC activity in AH patients and its potential impact on the severity and prognosis of this life‐threatening liver disease.
Methods
MRC complexes were measured in liver biopsies of 98 AH patients (non‐severe, 17; severe, 81) and in 12 histologically normal livers (NL). Severity was assessed according to Maddrey's Index and MELD score. Corticosteroid response rate and cumulative mortality were also evaluated.
Results
The activity of the five MRC complexes was markedly decreased in the liver of AH patients compared with that of NL subjects, being significantly lower in patients with severe AH than in those with non‐severe AH. There was a negative correlation between the activity of all MRC complexes and the severity of AH. Interestingly, only complex I and III activities showed a significant positive correlation with the corticosteroid response rate and a significant negative correlation with the mortality rate at all‐time points studied. In a multivariate regression analysis, besides the MELD score and the corticosteroid response rate, complex I activity was significantly associated with 3‐month mortality (OR = 6.03; p = 0.034) and complex III activity with 6‐month mortality (OR = 4.70; p = 0.041) in AH patients.
Conclusion
Our results indicate that MRC activity is markedly decreased in the liver of AH patients, and, particularly, the impairment of MRC complexes I and III activity appears to have a significant impact on the clinical outcomes of patients with AH.
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We investigate the cause of the low activity of mitochondrial complex I found in ob/ob mice with nonalcoholic fatty liver disease. In mitochondrial proteins from ob/ob mice, we assessed complex I ...activity, fully assembled complex I, and its subunits, oxygen consumption, gene expression of complex I subunits, and oxidative damage to DNA. In mitochondrial proteins from the liver of ob/ob mice, complex I activity, fully assembly of this complex and complex I subunits were markedly reduced. Likewise, gene expression of mitochondrial DNA-encoded subunits was significantly decreased in obese mice, but not nuclear DNA-encoded subunits. Treatment of obese mice with uric acid, anti-TNFα antibody or a mimic of manganese superoxide dismutase normalized all these abnormalities. “In vitro” addition of peroxynitrite to mitochondrial proteins from wild-type mice reproduced the abnormalities found in ob/ob mice (decreased complex I activity, the amount of fully assembled complex I, and its subunits, and mitochondrial oxygen consumption). Low activity of complex I found in ob/ob mice can be ascribed to a reduced amount of fully assembled complex, which may be attributed to degradation and reduced synthesis of its subunits by peroxynitrite. Exposure of mitochondrial proteins from normal mice to peroxynitrite reproduced the proteomic abnormalities present in ob/ob mice.
LINKED CONTENT
This article is linked to Solís‐Muñoz et al papers. To view these articles, visit https://doi.org/10.1111/apt.17434 and https://doi.org/10.1111/apt.17440
Activity of the oxidative phosphorylation system (OXPHOS) is decreased in humans and mice with nonalcoholic steatohepatitis. Nitro-oxidative stress seems to be involved in its pathogenesis. The aim ...of this study was to determine whether fatty acids are implicated in the pathogenesis of this mitochondrial defect. In HepG2 cells, we analyzed the effect of saturated (palmitic and stearic acids) and monounsaturated (oleic acid) fatty acids on: OXPHOS activity; levels of protein expression of OXPHOS complexes and their subunits; gene expression and half-life of OXPHOS complexes; nitro-oxidative stress; and NADPH oxidase gene expression and activity. We also studied the effects of inhibiting or silencing NADPH oxidase on the palmitic-acid-induced nitro-oxidative stress and subsequent OXPHOS inhibition. Exposure of cultured HepG2 cells to saturated fatty acids resulted in a significant decrease in the OXPHOS activity. This effect was prevented in the presence of a mimic of manganese superoxide dismutase. Palmitic acid reduced the amount of both fully-assembled OXPHOS complexes and of complex subunits. This reduction was due mainly to an accelerated degradation of these subunits, which was associated with a 3-tyrosine nitration of mitochondrial proteins. Pretreatment of cells with uric acid, an antiperoxynitrite agent, prevented protein degradation induced by palmitic acid. A reduced gene expression also contributed to decrease mitochondrial DNA (mtDNA)-encoded subunits. Saturated fatty acids induced oxidative stress and caused mtDNA oxidative damage. This effect was prevented by inhibiting NADPH oxidase. These acids activated NADPH oxidase gene expression and increased NADPH oxidase activity. Silencing this oxidase abrogated totally the inhibitory effect of palmitic acid on OXPHOS complex activity. We conclude that saturated fatty acids caused nitro-oxidative stress, reduced OXPHOS complex half-life and activity, and decreased gene expression of mtDNA-encoded subunits. These effects were mediated by activation of NADPH oxidase. That is, these acids reproduced mitochondrial dysfunction found in humans and animals with nonalcoholic steatohepatitis.
Visceral fat deposition is associated with impairment of glucose and lipid metabolism while leptin levels are frequently related to subcutaneous fat area. At present, there is considerable ...controversy regarding the role of visceral adipose tissue accumulation in the development of metabolic syndrome (MS). Here we show the effects of omentectomy on the liver and MS in a diet induced obesity rat model. Our results reveal that undergoing omentectomy previously the establishment of the diet-induced-obesity reduced significantly body weight gain and avoid the development of MS, including non-alcoholic fatty liver disease. Intriguingly, the significantly lower body weight gain was due to decreased food intake. Omentum drives obesity progression through leptin resistance mediated by C-reactive protein, Interleucin (IL)-6 and high lipolysis activity. Omentum removal reversed immediately the increased plasma levels of CRP and IL-6 and gradually food intake, weight gain, and features of MS in diet-induced-obesity. Omentectomy caused no changes in normal-weigh-rats. This report displays causal mechanism by which omentum promotes obesity and propose omentectomy as a promising procedure in MS prevention.
Acute‐on‐chronic liver failure (ACLF) is characterized by acute decompensation (AD) of cirrhosis, organ failure(s), and high 28‐day mortality. We investigated whether assessments of patients at ...specific time points predicted their need for liver transplantation (LT) or the potential futility of their care. We assessed clinical courses of 388 patients who had ACLF at enrollment, from February through September 2011, or during early (28‐day) follow‐up of the prospective multicenter European Chronic Liver Failure (CLIF) ACLF in Cirrhosis study. We assessed ACLF grades at different time points to define disease resolution, improvement, worsening, or steady or fluctuating course. ACLF resolved or improved in 49.2%, had a steady or fluctuating course in 30.4%, and worsened in 20.4%. The 28‐day transplant‐free mortality was low‐to‐moderate (6%‐18%) in patients with nonsevere early course (final no ACLF or ACLF‐1) and high‐to‐very high (42%‐92%) in those with severe early course (final ACLF‐2 or ‐3) independently of initial grades. Independent predictors of course severity were CLIF Consortium ACLF score (CLIF‐C ACLFs) and presence of liver failure (total bilirubin ≥12 mg/dL) at ACLF diagnosis. Eighty‐one percent had their final ACLF grade at 1 week, resulting in accurate prediction of short‐ (28‐day) and mid‐term (90‐day) mortality by ACLF grade at 3‐7 days. Among patients that underwent early LT, 75% survived for at least 1 year. Among patients with ≥4 organ failures, or CLIF‐C ACLFs >64 at days 3‐7 days, and did not undergo LT, mortality was 100% by 28 days. Conclusions: Assessment of ACLF patients at 3‐7 days of the syndrome provides a tool to define the emergency of LT and a rational basis for intensive care discontinuation owing to futility. (Hepatology 2015;62:243‐252)
Nonalcoholic fatty liver disease (NAFLD) is the most frequent histological finding in individuals with abnormal liver-function tests in the Western countries. In previous studies, we have shown that ...oxidative phosphorylation (OXPHOS) is decreased in individuals with NAFLD, but the cause of this mitochondrial dysfunction remains uncertain. The aims of this study were to determine whether feeding mice a high-fat diet (HFD) induces any change in the activity of OXPHOS, and to investigate the mechanisms involved in the pathogenesis of this defect. To that end, 30 mice were distributed between five groups: control mice fed a standard diet, and mice on a HFD and treated with saline solution, melatonin (an antioxidant), MnTBAP (a superoxide dismutase analog) or uric acid (a scavenger of peroxynitrite) for 28 weeks intraperitoneously. In the liver of these mice, we studied histology, activity and assembly of OXPHOS complexes, levels of subunits of these complexes, gene expression of these subunits, oxidative and nitrosative stress, and oxidative DNA damage. In HFD-fed mice, we found nonalcoholic steatohepatitis, increased gene expression of TNFα, IFNγ, MCP-1, caspase-3, TGFβ1 and collagen α1(I), and increased levels of 3-tyrosine nitrated proteins. The activity and assembly of all OXPHOS complexes was decreased to about 50-60%. The amount of all studied OXPHOS subunits was markedly decreased, particularly the mitochondrial-DNA-encoded subunits. Gene expression of mitochondrial-DNA-encoded subunits was decreased to about 60% of control. There was oxidative damage to mitochondrial DNA but not to genomic DNA. Treatment of HFD-fed mice with melatonin, MnTBAP or uric acid prevented all changes observed in untreated HFD-fed mice. We conclude that a HFD decreased OXPHOS enzymatic activity owing to a decreased amount of fully assembled complexes caused by a reduced synthesis of their subunits. Antioxidants and antiperoxynitrites prevented all of these changes, suggesting that nitro-oxidative stress played a key role in the pathogenesis of these alterations. Treatment with these agents might prevent the development of NAFLD in humans.
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