Sympathetic nervous activation, mitochondrial dysfunction and outcome in acutely decompensated cirrhosis: the metabolomic prognostic models (CLIF-C MET).

BACKGROUND AND AIMS: Current prognostic scores of patients with acutely decompensated cirrhosis (AD), particularly those with acute-on-chronic liver failure (ACLF), underestimate the risk of mortality. This is probably because systemic inflammation (SI), the major driver of AD/ACLF, is not reflected in the scores. SI induces metabolic changes, which impair delivery of the necessary energy for the immune reaction. This investigation aimed to identify metabolites associated with short-term (28-day) death and to design metabolomic prognostic models. METHODS: Two prospective multicentre large cohorts from Europe for investigating ACLF and development of ACLF, CANONIC (discovery, n=831) and PREDICT (validation, n=851), were explored by untargeted serum metabolomics to identify and validate metabolites which could allow improved prognostic modelling. RESULTS: Three prognostic metabolites strongly associated with death were selected to build the models. 4-Hydroxy-3-methoxyphenylglycol sulfate is a norepinephrine derivative, which may be derived from the brainstem response to SI. Additionally, galacturonic acid and hexanoylcarnitine are associated with mitochondrial dysfunction. Model 1 included only these three prognostic metabolites and age. Model 2 was built around 4-hydroxy-3-methoxyphenylglycol sulfate, hexanoylcarnitine, bilirubin, international normalised ratio (INR) and age. In the discovery cohort, both models were more accurate in predicting death within 7, 14 and 28 days after admission compared with MELDNa score (C-index: 0.9267, 0.9002 and 0.8424, and 0.9369, 0.9206 and 0.8529, with model 1 and model 2, respectively). Similar results were found in the validation cohort (C-index: 0.940, 0.834 and 0.791, and 0.947, 0.857 and 0.810, with model 1 and model 2, respectively). Also, in ACLF, model 1 and model 2 outperformed MELDNa 7, 14 and 28 days after admission for prediction of mortality. CONCLUSIONS: Models including metabolites (CLIF-C MET) reflecting SI, mitochondrial dysfunction and sympathetic system activation are better predictors of short-term mortality than scores based only on organ dysfunction (eg, MELDNa), especially in patients with ACLF.

Dysregulation of the Lysophosphatidylcholine/Autotaxin/Lysophosphatidic Acid Axis in Acute-on-Chronic Liver Failure Is Associated With Mortality and Systemic Inflammation by Lysophosphatidic Acid-Dependent Monocyte Activation.

BACKGROUND & AIMS: Acute-on-chronic liver failure (ACLF) is characterized by systemic inflammation, monocyte dysfunction, and susceptibility to infection. Lysophosphatidylcholines (LPCs) are immune-active lipids whose metabolic regulation and effect on monocyte function in ACLF is open for study. APPROACHES & RESULTS: Three hundred forty-two subjects were recruited and characterized for blood lipid, cytokines, phospholipase (PLA), and autotaxin (ATX) concentration. Peripheral blood mononuclear cells and CD14+ monocytes were cultured with LPC, or its autotaxin (ATX)-derived product, lysophosphatidic acid (LPA), with or without lipopolysaccharide stimulation and assessed for surface marker phenotype, cytokines production, ATX and LPA-receptor expression, and phagocytosis. Hepatic ATX expression was determined by immunohistochemistry. Healthy volunteers and patients with sepsis or acute liver failure served as controls. ACLF serum was depleted in LPCs with up-regulated LPA levels. Patients who died had lower LPC levels than survivors (area under the receiver operating characteristic curve, 0.94; P < 0.001). Patients with high-grade ACLF had the lowest LPC concentrations and these rose over the first 3 days of admission. ATX concentrations were higher in patients with AD and ACLF and correlated with Model for End-Stage Liver Disease, Consortium on Chronic Liver Failure-Sequential Organ Failure Assessment, and LPC/LPA concentrations. Reduction in LPC correlated with higher monocyte Mer-tyrosine-kinase (MerTK) and CD163 expression. Plasma ATX concentrations rose dynamically during ACLF evolution, correlating with IL-6 and TNF-α, and were associated with increased hepatocyte ATX expression. ACLF patients had lower human leukocyte antigen-DR isotype and higher CD163/MerTK monocyte expression than controls; both CD163/MerTK expression levels were reduced in ACLF ex vivo following LPA, but not LPC, treatment. LPA induced up-regulation of proinflammatory cytokines by CD14+ cells without increasing phagocytic capacity. CONCLUSIONS: ATX up-regulation in ACLF promotes LPA production from LPC. LPA suppresses MerTK/CD163 expression and increases monocyte proinflammatory cytokine production. This metabolic pathway could be investigated to therapeutically reprogram monocytes in ACLF.

CD14+ CD15- HLA-DR- myeloid-derived suppressor cells impair antimicrobial responses in patients with acute-on-chronic liver failure.

OBJECTIVE: Immune paresis in patients with acute-on-chronic liver failure (ACLF) accounts for infection susceptibility and increased mortality. Immunosuppressive mononuclear CD14+HLA-DR- myeloid-derived suppressor cells (M-MDSCs) have recently been identified to quell antimicrobial responses in immune-mediated diseases. We sought to delineate the function and derivation of M-MDSC in patients with ACLF, and explore potential targets to augment antimicrobial responses. DESIGN: Patients with ACLF (n=41) were compared with healthy subjects (n=25) and patients with cirrhosis (n=22) or acute liver failure (n=30). CD14+CD15-CD11b+HLA-DR- cells were identified as per definition of M-MDSC and detailed immunophenotypic analyses were performed. Suppression of T cell activation was assessed by mixed lymphocyte reaction. Assessment of innate immune function included cytokine expression in response to Toll-like receptor (TLR-2, TLR-4 and TLR-9) stimulation and phagocytosis assays using flow cytometry and live cell imaging-based techniques. RESULTS: Circulating CD14+CD15-CD11b+HLA-DR- M-MDSCs were markedly expanded in patients with ACLF (55% of CD14+ cells). M-MDSC displayed immunosuppressive properties, significantly decreasing T cell proliferation (p=0.01), producing less tumour necrosis factor-alpha/interleukin-6 in response to TLR stimulation (all p<0.01), and reduced bacterial uptake of Escherichia coli (p<0.001). Persistently low expression of HLA-DR during disease evolution was linked to secondary infection and 28-day mortality. Recurrent TLR-2 and TLR-4 stimulation expanded M-MDSC in vitro. By contrast, TLR-3 agonism reconstituted HLA-DR expression and innate immune function ex vivo. CONCLUSION: Immunosuppressive CD14+HLA-DR- M-MDSCs are expanded in patients with ACLF. They were depicted by suppressing T cell function, attenuated antimicrobial innate immune responses, linked to secondary infection, disease severity and prognosis. TLR-3 agonism reversed M-MDSC expansion and innate immune function and merits further evaluation as potential immunotherapeutic agent.

Mucosa-associated invariant T cells link intestinal immunity with antibacterial immune defects in alcoholic liver disease.

BACKGROUND/AIMS: Intestinal permeability with systemic distribution of bacterial products are central in the immunopathogenesis of alcoholic liver disease (ALD), yet links with intestinal immunity remain elusive. Mucosa-associated invariant T cells (MAIT) are found in liver, blood and intestinal mucosa and are a key component of antibacterial host defences. Their role in ALD is unknown. METHODS/DESIGN: We analysed frequency, phenotype, transcriptional regulation and function of blood MAIT cells in severe alcoholic hepatitis (SAH), alcohol-related cirrhosis (ARC) and healthy controls (HC). We also examined direct impact of ethanol, bacterial products from faecal extracts and antigenic hyperstimulation on MAIT cell functionality. Presence of MAIT cells in colon and liver was assessed by quantitative PCR and immunohistochemistry/gene expression respectively. RESULTS: In ARC and SAH, blood MAIT cells were dramatically depleted, hyperactivated and displayed defective antibacterial cytokine/cytotoxic responses. These correlated with suppression of lineage-specific transcription factors and hyperexpression of homing receptors in the liver with intrahepatic preservation of MAIT cells in ALD. These alterations were stronger in SAH, where surrogate markers of bacterial infection and microbial translocation were higher than ARC. Ethanol exposure in vitro, in vivo alcohol withdrawal and treatment with Escherichia coli had no effect on MAIT cell frequencies, whereas exposure to faecal bacteria/antigens induced functional impairments comparable with blood MAIT cells from ALD and significant MAIT cell depletion, which was not observed in other T cell compartments. CONCLUSIONS: In ALD, the antibacterial potency of MAIT cells is compromised as a consequence of contact with microbial products and microbiota, suggesting that the 'leaky' gut observed in ALD drives MAIT cell dysfunction and susceptibility to infection in these patients.

Incidence and Outcomes for Patients With Cirrhosis Admitted to the United Kingdom Critical Care Units.

OBJECTIVE: To assess the epidemiology and outcome of patients with cirrhosis following critical care unit admission. DESIGN: Retrospective cohort study. SETTING: Critical care units in England, Wales, and Northern Ireland participating in the U.K. Intensive Care National Audit and Research Centre Case Mix Programme. PATIENTS: Thirty-one thousand three hundred sixty-three patients with cirrhosis identified of 1,168,650 total critical care unit admissions (2.7%) admitted to U.K. critical care units between 1998 and 2012. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Ten thousand nine hundred thirty-six patients had alcohol-related liver disease (35%). In total, 1.6% of critical care unit admissions in 1998 had cirrhosis rising to 3.1% in 2012. The crude critical care unit mortality of patients with cirrhosis was 41% in 1998 falling to 31% in 2012 (p < 0.001). Crude hospital mortality fell from 58% to 46% over the study period (p < 0.001). Mean(SD) Acute Physiology and Chronic Health Evaluation II score in 1998 was 20.3 (8.5) and 19.5 (7.1) in 2012. Mean Acute Physiology and Chronic Health Evaluation II score for patients with alcohol-related liver disease in 2012 was 20.6 (7.0) and 19.0 (7.2) for non-alcohol-related liver disease (p < 0.001). In adjusted analysis, alcohol-related liver disease was associated with increased risk of death (odds ratio, 1.51 [95% CI, 1.42-1.62; p < 0.001]) with a year-on-year reduction in hospital mortality (adjusted odds ratio, 0.95/yr, [0.94-0.96, p < 0.001]). CONCLUSIONS: More patients with cirrhosis are being admitted to critical care units but with increasing survival rates. Patients with alcohol-related liver disease have reduced survival rates partly explained by higher levels of organ failure at admission. Patients with cirrhosis and organ failure warrant a trial of organ support and universal prognostic pessimism is not justified.

Defective monocyte oxidative burst predicts infection in alcoholic hepatitis and is associated with reduced expression of NADPH oxidase.

OBJECTIVE: In order to explain the increased susceptibility to serious infection in alcoholic hepatitis, we evaluated monocyte phagocytosis, aberrations of associated signalling pathways and their reversibility, and whether phagocytic defects could predict subsequent infection. DESIGN: Monocytes were identified from blood samples of 42 patients with severe alcoholic hepatitis using monoclonal antibody to CD14. Phagocytosis and monocyte oxidative burst (MOB) were measured ex vivo using flow cytometry, luminometry and bacterial killing assays. Defects were related to the subsequent development of infection. Intracellular signalling pathways were investigated using western blotting and PCR. Interferon-γ (IFN-γ) was evaluated for its therapeutic potential in reversing phagocytic defects. Paired longitudinal samples were used to evaluate the effect of in vivo prednisolone therapy. RESULTS: MOB, production of superoxide and bacterial killing in response to Escherichia coli were markedly impaired in patients with alcoholic hepatitis. Pretreatment MOB predicted development of infection within two weeks with sensitivity and specificity that were superior to available clinical markers. Accordingly, defective MOB was associated with death at 28 and 90 days. Expression of the gp91 phox subunit of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase was reduced in patients with alcoholic hepatitis demonstrating defective MOB. Monocytes were refractory to IFN-γ stimulation and showed high levels of a negative regulator of cytokine signalling, suppressor of cytokine signalling-1. MOB was unaffected by 7 days in vivo prednisolone therapy. CONCLUSIONS: Monocyte oxidative burst and bacterial killing is impaired in alcoholic hepatitis while bacterial uptake by phagocytosis is preserved. Defective MOB is associated with reduced expression of NADPH oxidase in these patients and predicts the development of infection and death.

Predicting Fluid Responsiveness in Acute Liver Failure: A Prospective Study.

BACKGROUND: The profound hemodynamic changes seen in acute liver failure (ALF) resemble the hyperdynamic state found in the later stages of septic shock. Vasopressor support frequently is required after initial volume therapy. Markers of preload dependency have not been studied in this patient group. Dynamic maneuvers such as passive leg raising or end-expiratory hold, which have shown good predictive accuracy in a general intensive care unit population, cannot be considered safe in this cohort because of the concerns of intracranial hypertension. METHODS: Mechanically ventilated patients with ALF admitted to a tertiary specialist intensive care unit in shock and multiorgan failure were enrolled. Markers of fluid responsiveness derived from transpulmonary thermodilution, pulse contour analysis, and echocardiography were compared between responders (cardiac index ≥15%) and nonresponders to a colloid fluid challenge (5 mL/kg predicted body weight). The ability to predict fluid responsiveness of stroke volume variation, pulse pressure variation (PPV), and respiratory change in peak (delta V peak) left ventricular outflow tract velocity for preload dependency were analyzed. RESULTS: Thirty-five patients (mean ± SD age, 38 [14] years, 13 male, 22 female]) were assessed after a single fluid challenge. Ten patients (29%) were fluid responders. Changes in cardiac index and stroke volume index in the cohort of 35 patients were correlated (R = 0.726 [99% confidence interval, 0.401-0.910]; P < .001). PPV predicted fluid responsiveness (area under the receiver operating characteristic curve [AUROC], 0.752 [95% confidence interval, 0.565-0.889]; P = .005; cutoff >9%). The AUROC for stroke volume variation was 0.678 ([95% confidence interval, 0.499-0.825]; P = .084; cutoff >11%). The AUROC for [delta] V peak before fluid bolus was 0.637 (95% confidence interval, 0.413-0.825; P = .322). CONCLUSIONS: PPV based on pulse contour analysis predicted fluid responsiveness in ALF.

Multivariate metabotyping of plasma predicts survival in patients with decompensated cirrhosis.

BACKGROUND & AIMS: Predicting survival in decompensated cirrhosis (DC) is important in decision making for liver transplantation and resource allocation. We investigated whether high-resolution metabolic profiling can determine a metabolic phenotype associated with 90-day survival. METHODS: Two hundred and forty-eight subjects underwent plasma metabotyping by (1)H nuclear magnetic resonance (NMR) spectroscopy and reversed-phase ultra-performance liquid chromatography coupled to time-of-flight mass spectrometry (UPLC-TOF-MS; DC: 80-derivation set, 101-validation; stable cirrhosis (CLD) 20 and 47 healthy controls (HC)). RESULTS: (1)H NMR metabotyping accurately discriminated between surviving and non-surviving patients with DC. The NMR plasma profiles of non-survivors were attributed to reduced phosphatidylcholines and lipid resonances, with increased lactate, tyrosine, methionine and phenylalanine signal intensities. This was confirmed on external validation (area under the receiver operating curve [AUROC]=0.96 (95% CI 0.90-1.00, sensitivity 98%, specificity 89%). UPLC-TOF-MS confirmed that lysophosphatidylcholines and phosphatidylcholines [LPC/PC] were downregulated in non-survivors (UPLC-TOF-MS profiles AUROC of 0.94 (95% CI 0.89-0.98, sensitivity 100%, specificity 85% [positive ion detection])). LPC concentrations negatively correlated with circulating markers of cell death (M30 and M65) levels in DC. Histological examination of liver tissue from DC patients confirmed increased hepatocyte cell death compared to controls. Cross liver sampling at time of liver transplantation demonstrated that hepatic endothelial beds are a source of increased circulating total cytokeratin-18 in DC. CONCLUSION: Plasma metabotyping accurately predicts mortality in DC. LPC and amino acid dysregulation is associated with increased mortality and severity of disease reflecting hepatocyte cell death.

Ability of King's College Criteria and Model for End-Stage Liver Disease Scores to Predict Mortality of Patients With Acute Liver Failure: A Meta-analysis.

BACKGROUND & AIMS: Several prognostic factors are used to identify patients with acute liver failure (ALF) who require emergency liver transplantation. We performed a meta-analysis to determine the accuracy of King's College criteria (KCC) versus the model for end-stage liver disease (MELD) scores in predicting hospital mortality among patients with ALF. METHODS: We performed a systematic search of the literature for articles published from 2001 through 2015 that compared the accuracy of the KCC with MELD scores in predicting hospital mortality in patients with ALF. We identified 23 studies (comprising 2153 patients) and assessed the quality of data, and then performed a meta-analysis of pooled sensitivity and specificity values, diagnostic odds ratios (DORs), and summary receiver operating characteristic curves. Subgroups analyzed included study quality, era, location (Europe vs non-Europe), and size; ALF etiology (acetaminophen-associated ALF [AALF] vs nonassociated [NAALF]); and whether or not the study included patients who underwent liver transplantation and if the study center was also a transplant center. RESULTS: The DOR for the KCC was 5.3 (95% confidence interval [CI], 3.7-7.6; 57% heterogeneity) and the DOR for MELD score was 7.0 (95% CI, 5.1-9.7; 48% heterogeneity), so the MELD score and KCC are comparable in overall accuracy. The summary area under the receiver operating characteristic curve values was 0.76 for the KCC and 0.78 for MELD scores. The KCC identified patients with AALF who died with 58% sensitivity (95% CI, 51%-65%) and 89% specificity (95% CI, 85%-93%), whereas MELD scores identified patients with AALF who died with 80% sensitivity (95% CI, 74%-86%) and 53% specificity (95% CI, 47%-59%). The KCC predicted hospital mortality in patients with NAALF with 58% sensitivity (95% CI, 54%-63%) and 74% specificity (95% CI, 69%-78%), whereas MELD scores predicted hospital mortality in patients with NAALF with 76% sensitivity (95% CI, 72%-80%) and 73% specificity (95% CI, 69%-78%). In patients with AALF, the KCC's DOR was 10.4 (95% CI, 4.9-22.1) and the MELD score's DOR was 6.6 (95% CI, 2.1-20.2). In patients with NAALF, the KCC's DOR was 4.16 (95% CI, 2.34-7.40) and the MELD score's DOR was 8.42 (95% CI, 5.98-11.88). CONCLUSIONS: Based on a meta-analysis of studies, the KCC more accurately predicts hospital mortality among patients with AALF, whereas MELD scores more accurately predict mortality among patients with NAALF. However, there is significant heterogeneity among studies and neither system is optimal for all patients. Given the importance of specificity in decision making for listing for emergency liver transplantation, MELD scores should not replace the KCC in predicting hospital mortality of patients with AALF, but could have a role for NAALF.

Neutrophil Toll-Like Receptor 9 Expression and the Systemic Inflammatory Response in Acetaminophen-Induced Acute Liver Failure.

OBJECTIVES: There is a marked propensity for patients with acetaminophen-induced acute liver failure to develop sepsis, which may culminate in multiple organ failure and death. Toll-like receptors sense pathogens and induce inflammatory responses, but whether this is protective or detrimental in acetaminophen-induced acute liver failure remains unknown. DESIGN, SETTING, AND PATIENTS: We assessed Toll-like receptor expression on circulating neutrophils and their function in 24 patients with acetaminophen-induced acute liver failure and compared with 10 healthy controls. INTERVENTIONS: Neutrophil Toll-like receptor 2, -4, and -9 expression and cytokine production and function were studied ex vivo at baseline and following stimulation with lipopolysaccharide, oligodeoxynucleotides, ammonium chloride, and interleukin-8. To examine the influence of acetaminophen-induced acute liver failure plasma and endogenous DNA on Toll-like receptors-9 expression, healthy neutrophils were incubated with acetaminophen-induced acute liver failure plasma with and without deoxyribonuclease-I. MEASUREMENTS AND MAIN RESULTS: Circulating neutrophil Toll-like receptor 9 expression was increased in acetaminophen-induced acute liver failure on day 1 compared with healthy controls (p = 0.0002), whereas Toll-like receptor 4 expression was decreased compared with healthy controls (p < 0.0001). Toll-like receptor 2 expression was unchanged. Neutrophil phagocytic activity was decreased, and spontaneous oxidative burst increased in all patients with acetaminophen-induced acute liver failure compared with healthy controls (p < 0.0001). Neutrophil Toll-like receptor 9 expression correlated with plasma interleukin-8 and peak ammonia concentration (r = 0.6; p < 0.05) and increased with severity of hepatic encephalopathy (grade 0-2 vs 3/4) and systemic inflammatory response syndrome score (0-1 vs 2-4) (p < 0.05). Those patients with advanced hepatic encephalopathy (grade 3/4) or high systemic inflammatory response syndrome score (2-4) on day 1 had higher neutrophil Toll-like receptor 9 expression, arterial ammonia concentration, and plasma interleukin-8 associated with neutrophil exhaustion. Healthy neutrophil Toll-like receptor 9 expression increased upon stimulation with acetaminophen-induced acute liver failure plasma, which was abrogated by preincubation with deoxyribonuclease-I. Intracellular Toll-like receptor 9 was induced by costimulation with interleukin-8 and ammonia. CONCLUSION: These data point to neutrophil Toll-like receptor 9 expression in acetaminophen-induced acute liver failure being mediated both by circulating endogenous DNA as well as ammonia and interleukin-8 in a synergistic manner inducing systemic inflammation, neutrophil exhaustion, and exacerbating hepatic encephalopathy.

Increased Survival for Patients With Cirrhosis and Organ Failure in Liver Intensive Care and Validation of the Chronic Liver Failure-Sequential Organ Failure Scoring System.

BACKGROUND & AIMS: During the past decade, survival has increased among patients admitted to general intensive care units, but it is not clear if it has increased for patients admitted with cirrhosis and organ failure. The chronic liver failure-sequential organ failure assessment (CLIF-SOFA) recently was developed as an adaptation to the SOFA to predict outcomes of patients, but requires validation. We investigated changes in outcomes of patients with cirrhosis and organ failure since 2000, compared the abilities of SOFA and CLIF-SOFA to predict patient survival, and validated the CLIF-SOFA system. METHODS: In a retrospective study, we collected data from 971 patients (median age, 52 y; age range, 16-90 y; 62% male) with cirrhosis (54% alcohol associated, 12% viral, and 34% other causes). The patients were admitted under emergency conditions from January 1, 2000, to December 31, 2010, to a liver intensive therapy unit in the United Kingdom. Patient survival while in the hospital was compared with measures of illness severity, Acute Physiology and Chronic Health Evaluation (APACHE) II scores, model for end-stage liver disease (MELD) scores, SOFA scores, and CLIF-SOFA scores. RESULTS: Patients had a median APACHE II score of 21 (range, 5-50) and a median MELD score of 23 (range, 6-40). The median APACHE II score at admission decreased from 23 to 22 over the study period (P < .001), whereas the median MELD score at admission decreased from 23 to 18 (P < .001). Overall survival until hospital discharge was 51%; this value increased from 40% in 2000 to 63% in 2010 (P < .001). The unadjusted odds ratio for change in mortality/year was 0.87 (95% confidence interval, 0.83-0.91; P < .001). The APACHE II score adjusted odds ratio for mortality was 0.89 (95% confidence interval, 0.84-0.93; P < .001). The etiology of cirrhosis was not associated with a significant difference in survival. CLIF-SOFA and SOFA scores at the time of admission predicted patient survival with area under the receiver operating curve (AUROC) values of 0.813 and 0.799, respectively; the scores at 48 hours after admission predicted survival with AUROC values of 0.853 and 0.840, and scores after 1 week predicted survival with AUROC values of 0.842 and 0.844, respectively. These AUROC values were higher than those obtained from APACHE II or MELD scores. CONCLUSIONS: The proportion of patients with cirrhosis who survived after admission to intensive care increased from 2000 to 2010. SOFA and CLIF-SOFA scores during the first week of critical care appear to have similar abilities to predict patient survival.

Modulation of monocyte/macrophage function: a therapeutic strategy in the treatment of acute liver failure.

Acute liver failure (ALF) is a condition with a high mortality and morbidity for which new treatments are desperately required. We contend that although the initial event in ALF is liver cell death, the clinical syndrome of ALF and its complications including multi-organ dysfunction and sepsis, are largely generated by the immune response to liver injury. Hepatic macrophages fulfil a diversity of roles in ALF, from pro-inflammatory to pro-resolution. Their inherent plasticity means the same macrophages may have a variety of functions depending on the local tissue environment at different stages of disease. A better understanding of the mechanisms that regulate macrophage plasticity during ALF will be an essential step towards realising the potential of immune-modulating therapies that re-orientate macrophages to promote the desirable functions of attenuating liver injury and promoting liver repair/regenerative responses. The key dynamics: temporal (early vs. late phase), regional (hepatic vs. systemic), and activation (pro-inflammatory vs. pro-resolution) are discussed and the potential for novel ALF therapies that modulate monocyte/macrophage function are described.

Prognosis of acute severe autoimmune hepatitis (AS-AIH): the role of corticosteroids in modifying outcome.

BACKGROUND & AIMS: No standardised definition exists for acute, severe AIH (AS-AIH). However, rapid identification of AS-AIH and early corticosteroid therapy may prevent the need for liver transplantation (LT). We set out to determine the clinical outcomes of patients with AS-AIH presenting to our institution with particular focus on the role of corticosteroids. METHODS: Retrospective analysis of a prospectively collated database identified patients presenting with AS-AIH from 1999 to 2009. We defined AS-AIH as an acute presentation with an INR of ⩾1.5 at any time without histological evidence of cirrhosis. RESULTS: 32 patients were identified with AS-AIH. Among the 32 AS-AIH patients 23 were treated with corticosteroids of whom 10 (48%) required LT, whilst all 9 untreated patients required LT (p = 0.01). Untreated patients demonstrated higher MELD scores at presentation (34 vs. 28 p = 0.01) and a non-significant decrease in episodes of sepsis but no difference in sepsis or mortality was observed between untreated or treated patients (11% vs. 26% p = 0.6 and 22% vs. 17% p = 0.99 respectively). Among treated patients, no difference in MELD scores was observed between responders or failures. Despite 59% undergoing LT, six deaths (19%) occurred. CONCLUSION: In a well characterised cohort of patients with AS-AIH, almost 60% required LT and 20% died. There was no difference in prognostic scores between steroid responders and failures and steroid exposure did not appear to jeopardise survival. Patients with AS-AIH should be considered for a trial of corticosteroids expediently whilst a thorough search for sepsis and assessment for LT should occur if clinical deterioration or encephalopathy develops.

Lung injury and its prognostic significance in acute liver failure.

OBJECTIVE: Hypoxemia is a feared complication of acute liver failure, and high oxygen requirements will frequently lead to removal of patients from the transplant list. As data regarding the prevalence and outcome of acute respiratory distress syndrome in acute liver failure are scant and hypoxemia being a commonly encountered systemic complication, we analyzed radiological, gas exchange, and ventilator data in consecutive patients admitted with acute liver failure. PATIENTS: Acute liver failure patients receiving mechanical ventilation admitted between January 2007 and February 2011 were included. INTERVENTIONS: Patients were categorized according to the Berlin definition as: no acute respiratory distress syndrome, acute respiratory distress syndrome (PaO2/FIO2 < 300 mm Hg), and subdivisions of mild, moderate, and severe acute respiratory distress syndrome (200-300 mm Hg, 100-200 mm Hg, and < 100 mm Hg, respectively). Chest radiographs were independently assessed by two observers for the presence or absence of acute respiratory distress syndrome. Absence of left atrial pressure elevation was based on combined hemodynamic and echocardiographic assessment. MEASUREMENTS AND MAIN RESULTS: Two hundred acute liver failure patients were admitted during the study period of whom 148, median age 39 years (16-74 yr), were included. Thirty-one (21%) had acute respiratory distress syndrome (17 mild acute respiratory distress syndrome [12%], 9 moderate acute respiratory distress syndrome [12%], and 5 severe acute respiratory distress syndrome) within the first 72 hours following admission. Acute respiratory distress syndrome patients required higher positive end-expiratory pressure (7 vs 6 vs 10 vs 15 cm H2O for no, mild, moderate, or severe acute respiratory distress syndrome, p = 0.014), had reduced respiratory system compliance (34 vs 29 vs 30 vs 23 L/cm H2O, p = 0.028), and an increased number of ventilator days (no acute respiratory distress syndrome, 10 d; mild acute respiratory distress syndrome acute lung injury, 12 d; moderate acute respiratory distress syndrome, 23 d; severe acute respiratory distress syndrome, 22 d; p = 0.097). Duration of liver intensive therapy unit stay (p = 0.175), survival (p = 0.877), inotrope requirements (p = 0.495), need for extracorporeal renal support (p = 0.565), and severity of organ failure scores were not affected. Extravascular lung water index had a moderate sensitivity of 65% and specificity of 77% for the prediction of acute respiratory distress syndrome. CONCLUSION: The prevalence of lung injury is relatively low in acute liver failure, where 21% fulfilled acute respiratory distress syndrome criteria. Overall presence of acute respiratory distress syndrome appeared to have a limited impact on outcome.

Circulating neutrophil dysfunction in acute liver failure.

UNLABELLED: Systemic inflammation and susceptibility to developing sepsis is common in acute liver failure (ALF) resulting in tissue damage and organ failure. This study characterized the function of circulating neutrophils in 25 patients with ALF and subacute liver failure (SALF). ALF (n=15)/SALF (n=10) patients were prospectively studied and compared with 11 healthy (HC) and 6 septic controls (SC). Neutrophils were isolated on admission to intensive care and every 3-4 days until death / liver transplantation / recovery. Neutrophil phenotype was determined using fluorochrome-labeled antibodies to CD16 and CD11b and assessed by flow cytometry. Neutrophil phagocytic activity (NPA) was determined using fluorescein isothiocyanate-labeled opsonized Escherichia coli and oxidative burst (OB) was determined by the percentage of neutrophils producing reactive oxygen species (ROS) at rest and after stimulation with opsonized E. coli. Physiological variables, biochemistry, arterial ammonia, microbiology, and outcomes were collected. Plasma pro- and antiinflammatory cytokine profiles were performed by enzyme-linked immunosorbent assay. Neutrophil expression of CD16 which recognizes the FcγRIII region of immunoglobulin G was significantly reduced in the ALF cohort (P<0.001) on day 1 compared to HC. NPA was significantly impaired in the SALF cohort compared to HC (P<0.01). Impaired NPA in the ALF and SALF cohorts on admission predicted nonsurvival without liver transplantation (P=0.01). Spontaneous neutrophil production of ROS was not significantly increased in any of the cohorts. E. coli-stimulated OB was preserved in ALF/SALF cohorts but was significantly impaired in the SC group (P<0.05). CONCLUSION: Circulating neutrophils in ALF/SALF have impaired bacteriocidal function similar to that seen in severe sepsis. Neutrophil function indices are important biomarkers in ALF and may be implicated in the development of organ dysfunction and the increased susceptibility to developing sepsis.

Ammonia clearance with haemofiltration in adults with liver disease.

BACKGROUND & AIMS: Ammonia is recognized as a toxin central to complications of liver failure. Hyperammonaemia has important clinical consequences, but optimal means to reduce circulating levels are uncertain. In patients with liver disease, continuous renal replacement therapy (CRRT) with haemofiltration (HF) is often required to treat concurrent kidney injury, but its effects upon ammonia levels are poorly characterized. To evaluate the effect of HF at different treatment intensities on ammonia clearance (AC) and arterial ammonia concentration. METHODS: Prospective study of adult patients with liver failure and arterial ammonia >100 µmol/L requiring CRRT using veno-venous HF. Arterial ammonia concentration and AC measured at 1 and 24 h after initiation of low (35 ml/kg/h) or high (90 ml/kg/h) filtration volume. RESULTS: Twenty-four patients (10 acute liver failure, 10 chronic liver disease and 4 following liver resection) were studied. Clearance of urea and ammonia solutes correlated closely (r = 0.819, P = 0.007). Ammonia clearance correlated closely with ultrafiltration rate (r = 0.86, P < 0.001). At 1 h, AC was 39 (34-54) ml/min (low volume) vs 85 (62-105) ml/min (high volume) CRRT, (P < 0.001) and at 24 h 44 (34-63) vs 105 (82-109) ml/min, (P = 0.01). Overall, a 22% reduction in median arterial ammonia concentration was observed over 24 h of HF from 156 (137-176) to 122 (85-133) µmol/L, (P ≤ 0.0001). CONCLUSION: Clinically significant ammonia clearance can be achieved in adult patients with hyperammonaemia utilizing continuous VVHF. Ammonia clearance is closely correlated with ultrafiltration rate. HF was associated with a fall in arterial ammonia concentration.

Portopulmonary hypertension: improved detection using CT and echocardiography in combination.

OBJECTIVES: To establish the relationship between CT signs of pulmonary hypertension and mean pulmonary artery pressure (mPAP) in patients with liver disease, and to determine the additive value of CT in the detection of portopulmonary hypertension in combination with transthoracic echocardiography. METHODS: Forty-nine patients referred for liver transplantation were retrospectively reviewed. Measured CT signs included the main pulmonary artery/ascending aorta diameter ratio (PA/AAmeas) and the mean left and right main PA diameter (RLPAmeas). Enlargement of the pulmonary artery compared to the ascending aorta was also assessed visually (PA/AAvis). CT measurements were correlated with right-sided heart catheter-derived mPAP. The ability of PA/AAvis combined with echocardiogram-derived right ventricular systolic pressure (RVSP) to detect portopulmonary hypertension was tested with ROC analysis. RESULTS: There were moderate correlations between mPAP and both PA/AAmeas and RLPAmeas (rs = 0.41 and rs = 0.42, respectively; p < 0.005). Compared to transthoracic echocardiography alone (AUC = 0.59, p = 0.23), a diagnostic algorithm incorporating PA/AAvis and transthoracic echocardiography-derived RVSP improved the detection of portopulmonary hypertension (AUC = 0.8, p < 0.0001). CONCLUSIONS: CT contributes to the non-invasive detection of portopulmonary hypertension when used in a diagnostic algorithm with transthoracic echocardiography. CT may have a role in the pre-liver transplantation triage of patients with portopulmonary hypertension for right-sided heart catheterisation. KEY POINTS: • CT signs correlate with right-sided heart catheter data in portopulmonary hypertension • CT adds to the transthoracic echocardiography detection of portopulmonary hypertension • CT may have a complementary role in pre-liver transplantation triage.

Character and temporal evolution of apoptosis in acetaminophen-induced acute liver failure*.

OBJECTIVE: To evaluate the role of hepatocellular and extrahepatic apoptosis during the evolution of acetaminophen-induced acute liver failure. DESIGN AND SETTING: A prospective observational study in two tertiary liver transplant units. PATIENTS: Eighty-eight patients with acetaminophen-induced acute liver failure were recruited. Control groups included patients with nonacetaminophen-induced acute liver failure (n = 13), nonhepatic multiple organ failure (n = 28), chronic liver disease (n = 19), and healthy controls (n = 11). MEASUREMENTS: Total and caspase-cleaved cytokeratin-18 (M65 and M30) measured at admission and sequentially on days 3, 7, and 10 following admission. Levels were also determined from hepatic vein, portal vein, and systemic arterial blood in seven patients undergoing transplantation. Protein arrays of liver homogenates from patients with acetaminophen-induced acute liver failure were assessed for apoptosis-associated proteins, and histological assessment of liver tissue was performed. MAIN RESULTS: Admission M30 levels were significantly elevated in acetaminophen-induced acute liver failure and non-acetaminophen induced acute liver failure patients compared with multiple organ failure, chronic liver disease, and healthy controls. Admission M30 levels correlated with outcome with area under receiver operating characteristic of 0.755 (0.639-0.885, p < 0.001). Peak levels in patients with acute liver failure were seen at admission then fell significantly but did not normalize over 10 days. A negative gradient of M30 from the portal to hepatic vein was demonstrated in patients with acetaminophen-induced acute liver failure (p = 0.042) at the time of liver transplant. Analysis of protein array data demonstrated lower apoptosis-associated protein and higher catalase concentrations in acetaminophen-induced acute liver failure compared with controls (p < 0.05). Explant histological analysis revealed evidence of cellular proliferation with an absence of histological evidence of apoptosis. CONCLUSIONS: Hepatocellular apoptosis occurs in the early phases of human acetaminophen-induced acute liver failure, peaking on day 1 of hospital admission, and correlates strongly with poor outcome. Hepatic regenerative/tissue repair responses prevail during the later stages of acute liver failure where elevated levels of M30 are likely to reflect epithelial cell death in extrahepatic organs.

The association of pretransplant ferritin level with waiting list and post-transplant survival. Does ferritin actually predict outcome?

Recent data suggest an association of serum ferritin (SF) with waiting list (WL) and postliver transplant (LT) outcomes. To assess the predictive capacity of SF on pre- and post-LT outcomes, and to identify whether recipient or donor liver siderosis is associated with post-LT survival; a retrospective analysis of 1079 patients assessed for first LT, 2000-2007 was performed. Iron deposition in the liver tissue was assessed using a semi-quantitative grading system. Median age was 54 (18-82) years and 67% were male. Seventeen per cent had hepatocellular carcinoma (HCC). Median Model for End-stage Liver Disease MELD score was 14 (6-40), ferritin was 174 µg/l (4-4597) with 36.5% had a SF ≥ µg/l. Age (OR = 1.028) and MELD score (OR = 1.158) were independently associated with WL mortality (P < 0.001), whilst SF was not (P = NS). Age (OR = 1.018), HCC (OR = 1.542) and cold ischemia time (CIT) ≥ 10 h (OR = 1.418) were independently associated with post-LT survival (P < 0.05). Explant siderosis grade <2 was seen in 376 (71.7%) patients. Patients with explant siderosis grade ≥ 2 had inferior 12-month post-LT survival (P = 0.030). Presence of graft siderosis (15.8% of patients) was not associated with survival. In conclusion, we found a limited role for SF as a prognostic indicator for pre- or post-transplant survival.

Acute liver failure and the brain: a look through the crystal ball.

Over the past 35 years, the outlook for a patient presenting with acute liver failure (ALF) has changed beyond all recognition. A patient presenting in 1984 had an 80 % likelihood of succumbing to intracranial hypertension. Today due to dramatic improvements in intensive care in dedicated liver transplant units, this has been reduced to just 20 %. Prompt fluid resuscitation, empirical treatment for sepsis and standardised management protocols that include early intubation and high flow hemofiltration for ammonia removal, limit the numbers of patients who die from the sequelae of cerebral edema and ALF. With the evolution and development of bedside prognostic markers that will include personalised genomic, metabonomic and immune profiling, rationalisation of grafts to those who are not predicted to survive is likely to further minimise the number of grafts utilised. Furthermore, in those patients with a dismal prognosis, the use of plasmapheresis, immunomodulatory therapies, biological liver support systems and hepatocyte transplantation offer a potential bridge until the injured liver can begin to regenerate avoiding transplantation and life-long immunosuppressant therapy.