Role of ammonia, inflammation, and cerebral oxygenation in brain dysfunction of acute-on-chronic liver failure patients

Investigation of Post-Transplant Mental Well-Being in Liver Transplant Recipients with Hepatic Encephalopathy

Objective: In this study, we aimed to examine the healing trend of hepatic encephalopathy after transplantation surgery in patients with liver failure. Method: We conducted this descriptive and cross-sectional study with the participation of liver transplant recipients. A personal information form, the West Haven Criteria (WHC), the Warwick-Edinburgh Mental Well-Being Scale (WEMWBS), and the Richmond Agitation Sedation Scale (RASS) were used for data collection. The data were analyzed using Chi-squared tests, ANOVA, and paired-samples t-tests. Results: As time progressed after liver transplantation, hepatic encephalopathy stages regressed (p < 0.01). We found that liver transplant recipients with end-stage hepatic encephalopathy were mostly within the first 6 months after transplantation, while patients with first-stage hepatic encephalopathy had received liver transplants more than 2 years ago (p < 0.01). Conclusions: The results of our study revealed that hepatic encephalopathy stages regressed after transplantation, but there was no complete recovery. This highlights the need to develop new treatment strategies other than liver transplantation for the treatment of hepatic encephalopathy.

Recent advances in the prevention and treatment of decompensated cirrhosis and acute-on-chronic liver failure (ACLF) and the role of biomarkers

The progression of cirrhosis with clinically significant portal hypertension towards decompensated cirrhosis remains clinically challenging and the evolution towards acute-on-chronic liver failure (ACLF), with one or more extrahepatic organ failures, is associated with very high mortality. In the last decade, significant progress has been made in the understanding of the mechanisms leading to decompensation and ACLF. As portal hypertension advances, bacterial translocation across an impaired gut barrier culminates in endotoxaemia, systemic inflammation and cirrhosis-associated immune dysfunction (CAID). Gut-derived systemic inflammation and CAID have become the logical targets for innovative therapies that prevent hepatic decompensation episodes and the progression to ACLF.Furthermore, classification of disease and biomarker discovery to personalise care have advanced in the field. This review discusses progress in biomarker discovery and personalisation of treatment in decompensated cirrhosis and ACLF.

Lessons on brain edema in HE: from cellular to animal models and clinical studies

Brain edema is considered as a common feature associated with hepatic encephalopathy (HE). However, its central role as cause or consequence of HE and its implication in the development of the neurological alterations linked to HE are still under debate. It is now well accepted that type A and type C HE are biologically and clinically different, leading to different manifestations of brain edema. As a result, the findings on brain edema/swelling in type C HE are variable and sometimes controversial. In the light of the changing natural history of liver disease, better description of the clinical trajectory of cirrhosis and understanding of molecular mechanisms of HE, and the role of brain edema as a central component in the pathogenesis of HE is revisited in the current review. Furthermore, this review highlights the main techniques to measure brain edema and their advantages/disadvantages together with an in-depth description of the main ex-vivo/in-vivo findings using cell cultures, animal models and humans with HE. These findings are instrumental in elucidating the role of brain edema in HE and also in designing new multimodal studies by performing in-vivo combined with ex-vivo experiments for a better characterization of brain edema longitudinally and of its role in HE, especially in type C HE where water content changes are small.

Serum ammonia variation predicts mortality in patients with hepatitis B virus-related acute-on-chronic liver failure

Background

Hyperammonemia is critical to the development of hepatic encephalopathy (HE) and is associated with mortality in end-stage liver disease. This study investigated the clinical value of ammonia variation in hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) patients.

Methods

A total of 276 patients with HBV-ACLF were retrospectively recruited. Patients' ammonia levels were serially documented. Baseline ammonia, Peak ammonia (highest level), and Trough ammonia (lowest level) were particularly corrected to the upper limit of normal (AMM-ULN). The primary endpoint was 28-day mortality.

Results

The 28-day, 3-month, and 12-month mortality rates were 19.2, 25.7, and 28.2%, respectively. A total of 51 (18.4%) patients had overt HE (grade 2/3/4). Peak AMM-ULN was significantly higher in patients with overt HE and non-survivors compared with their counterparts (P < 0.001). Following adjustment for significant confounders, high Peak AMM-ULN was an independent predictor of overt HE (hazard ratio, 1.031, P < 0.001) and 28-day mortality (hazard ratio, 1.026, P < 0.001). The cut-off of Peak AMM-ULN was 1.8, determined by using the X-tile. Patients with Peak AMM-ULN appearing on days 1-3 after admission had a higher proportion of overt HE and mortality compared to other groups. Patients with decreased ammonia levels within 7 days had better clinical outcomes than those with increased ammonia.

Conclusion

Serum Peak ammonia was independently associated with overt HE and mortality in HBV-ACLF patients. Serial serum ammonia may have prognostic value.

Novel Therapeutic Approaches in Treatment of Acute-on-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF), a clinical syndrome that can develop at any stage in the progression of cirrhotic liver disease, is characterized by an acute decompensation in liver function with associated multiorgan failure and high short-term mortality. Current evidence points to ACLF being reversible, particularly in those at the lower end of the severity spectrum. However, there are no specific treatments for ACLF, and overall outcomes remain poor. Expedited liver transplantation as a treatment option is limited by organ shortage and a lack of priority allocation for this indication. Other options are therefore urgently needed, and our improved understanding of the condition has led to significant efforts to develop novel therapies. In conclusion, this review aims to summarize the current understanding of the pathophysiological processes involved in the onset, progression, and recovery of ACLF and discuss novel therapies under development.

Intravenous BCAA Infusion Does Not Lead to a Sustained Recovery From Overt HE in ACLF - An Open Label Randomized Clinical Trial

Background

Hepatic encephalopathy (HE) in acute-on-chronic liver failure (ACLF) is associated with significant morbidity and mortality. We conducted a prospective, randomized controlled clinical trial to study the efficacy of intravenous branched chain amino acids (IV-BCAA) with lactulose versus lactulose alone for improvement in HE at 24 h, day 3, and day 7. The primary outcome was an improvement in encephalopathy by ≥ 1 grade at 72 h.

Patients and methods

European association for study of liver (EASL) defined ACLF patients with overt HE were assessed and randomized into the experimental arm (IV-BCAA - 500 mL/day for 3 days + Lactulose; n = 39) and the comparator arm (Lactulose alone; n = 37). Six patients developed COVID-19 after randomization and were excluded (4-experimental arm and 2-comparator arm).

Results

Of 222 screened patients, 70 (35 in each arm) were included in the analysis. Baseline characteristics, including HE grade (2.9 ± 0.7 vs 2.8 ± 0.7; P = 0.86) and (chronic liver failure) CLIF-C ACLF score (54.2 ± 5.6 vs 54.8 ± 5.7; P = 0.65), were similar. Overall survival was 40% at 28 days (48.5% vs 31.4%; P = 0.14). Improvement in hepatic encephalopathy scoring algorithm (HESA) by ≥ 1 grade at 24 h occurred in 14 patients (40%) in the BCAA arm and 6 patients (17.1%) in the control group (P = 0.03) which translated to a shorter intensive care unit (ICU) stay. The median change in HESA at 24 h was greater in the BCAA arm than the control arm (P = 0.006), which was not sustained at days 3 or 7. Ammonia levels did not correlate with the grade of HE (Spearman's correlation coefficient (ρ) = - 0.0843; P = 0.29).

Conclusion

Intravenous BCAA does not lead to a sustained improvement in HE grade in ACLF.

Trial registration no

NCT04238416 (clinicaltrials.gov).

Early serum ammonia variation in critically ill patients with cirrhosis: A multicentre cohort study

BACKGROUND

Serum ammonia variation in critically ill patients with cirrhosis has been poorly studied.

AIM

To describe and assess the impact of serum ammonia variation in these patients' outcomes.

METHODS

We studied patients ≥18 years old admitted to the intensive care units (ICUs) at University of Alberta Hospital (Edmonton, Canada) and Curry Cabral Hospital (Lisbon, Portugal; derivation cohort, n = 492) and Northwestern University Hospital (Chicago, USA; validation cohort, n = 600) between January 2010 and December 2021. Primary exposure was ICU days 1-3 serum ammonia. Primary endpoint was all-cause hospital mortality.

RESULTS

In the derivation cohort, 330 (67.1%) patients were male and median (IQR) age was 57 (50-63) years. On ICU day 1, median ammonia was higher in patients with grade 3/4 hepatic encephalopathy (HE) than those with grade 2 HE or grade 0/1 HE (112 vs. 88 vs. 77 μmoL/L, respectively; p < 0.001). Furthermore, medium ammonia was higher in hospital non-survivors than survivors (99 vs. 86 μmol/L; p < 0.030). Following adjustment for significant confounders (age, HE, vasopressor use and renal replacement therapy delivery), higher ICU day 2 ammonia was independently associated with higher hospital mortality (adjusted OR per each 10 μmoL/L increment [95% CI] = 1.11 [1.01-1.21]; p = 0.024). In the validation cohort, this model with serial ammonia (ICU days 1 and 3) predicted hospital mortality with reasonably good discrimination (c-statistic = 0.73) and calibration (R2  = 0.19 and Brier score = 0.17).

CONCLUSIONS

Among patients with cirrhosis in the ICU, early serum ammonia variation was independently associated with hospital mortality. In this context, serial serum ammonia may have prognostic value.

Pharmacokinetics of AXA1665, a Novel Composition of Amino Acids, in Comparison With Protein Supplement: A Single-Dose, Open-Label, Randomized Study in Healthy Subjects

We evaluated the safety and tolerability of AXA1665, a novel investigational fixed-ratio amino acid (AA) composition, the pharmacokinetics (PK) of the constituent AAs within AXA1665, and their relative bioavailability versus standard protein supplement. This study was conducted in 2 phases; in the initial phase, healthy subjects (N = 16) were randomly assigned to 4 treatment sequences (AXA1665 4.9, 9.8, and 19.6 g or 35 g protein supplement) in an open-label, single-dose, 4-way crossover study, while in the extension phase, they received single AXA1665 doses of 29.4 and 39.2 g in a sequential crossover manner. The net area under the plasma concentration-time curve (AUC) and observed time to reach maximum plasma concentration were estimated. A dose-dependent increase in plasma AUC from time 0 to the last measurable concentration (AUClast ) and maximum plasma concentration (Cmax ) was observed for all AXA1665-dosed AAs (4.9-39.2 g) except aspartic acid. AXA1665 19.6 g resulted in 1.5- to 9.5-fold higher systemic exposure to all AXA1665-dosed AAs except for aspartic acid and lysine and lower exposure to all nondosed AAs except for glutamine and alanine versus protein supplement. AXA1665 doses, up to 39.2 g, can deliver AXA1665-dosed AAs in the systemic circulation in the linear AUC range.

Plasma ammonia levels predict hospitalisation with liver-related complications and mortality in clinically stable outpatients with cirrhosis

BACKGROUND & AIMS

Hyperammonaemia is central in the pathogenesis of hepatic encephalopathy. It also has pleiotropic deleterious effects on several organ systems, such as immune function, sarcopenia, energy metabolism and portal hypertension. This study was performed to test the hypothesis that severity of hyperammonaemia is a risk factor for liver-related complications in clinically stable outpatients with cirrhosis.

METHODS

We studied 754 clinically stable outpatients with cirrhosis from 3 independent liver units. Baseline ammonia levels were corrected to the upper limit of normal (AMM-ULN) for the reference laboratory. The primary endpoint was hospitalisation with liver-related complications (a composite endpoint of bacterial infection, variceal bleeding, overt hepatic encephalopathy, or new onset or worsening of ascites). Multivariable competing risk frailty analyses using fast unified random forests were performed to predict complications and mortality. External validation was carried out using prospective data from 130 patients with cirrhosis in an independent tertiary liver centre.

RESULTS

Overall, 260 (35%) patients were hospitalised with liver-related complications. On multivariable analysis, AMM-ULN was an independent predictor of both liver-related complications (hazard ratio 2.13; 95% CI 1.89-2.40; p <0.001) and mortality (hazard ratio 1.45; 95% CI 1.20-1.76; p <0.001). The AUROC of AMM-ULN was 77.9% for 1-year liver-related complications, which is higher than traditional severity scores. Statistical differences in survival were found between high and low levels of AMM-ULN both for complications and mortality (p <0.001) using 1.4 as the optimal cut-off from the training set. AMM-ULN remained a key variable for the prediction of complications within the random forests model in the derivation cohort and upon external validation.

CONCLUSION

Ammonia is an independent predictor of hospitalisation with liver-related complications and mortality in clinically stable outpatients with cirrhosis and performs better than traditional prognostic scores in predicting complications.

LAY SUMMARY

We conducted a prospective cohort study evaluating the association of blood ammonia levels with the risk of adverse outcomes in 754 patients with stable cirrhosis across 3 independent liver units. We found that ammonia is a key determinant that helps to predict which patients will be hospitalised, develop liver-related complications and die; this was confirmed in an independent cohort of patients.

Blood ammonia in patients with chronic liver diseases: A better defined role in clinical practice

Ammonia is one of the main players in the pathogenesis of hepatic encephalopathy (HE) in patients with chronic liver diseases. The usefulness of measuring ammonemia has been debated since many years. New data reveal that besides helping in the differential diagnosis of HE, ammonemia could be a prognostic marker not only in patients with HE, but also in patients without any neurological symptoms, suggesting a potential toxic role of ammonia beyond the brain. Finally, targeting ammonemia while monitoring therapeutic response could be a way to improve outcomes in patients with HE.

Metabolomics profiles in acute-on-chronic liver failure: Unveiling pathogenesis and predicting progression

Acute-on-chronic liver failure (ACLF) usually develops based on acute decompensation (AD) of cirrhosis and is characterized by intense systemic inflammation, multiple organ failure, and high short-term mortality. Validated biomarkers for the diagnosis and prognosis of ACLF remain to be clarified. Metabolomics is an emerging method used to measure low-molecular-weight metabolites and is currently frequently implemented to understand pathophysiological processes involved in disease progression, as well as to search for new diagnostic or prognostic biomarkers of various disorders. The characterization of metabolites in ACLF has recently been described via metabolomics. The role of metabolites in the pathogenesis of ACLF deserves further investigation and improvement and could be the basis for the development of new diagnostic and therapeutic strategies. In this review, we focused on the contributions of metabolomics on uncovering metabolic profiles in patients with ACLF, the key metabolic pathways that are involved in the progression of ACLF, and the potential metabolite-associated therapeutic targets for ACLF.

Heretical thoughts into hepatic encephalopathy

Clinical progress in the development of new diagnostic modalities and therapeutic strategies for the management of patients with hepatic encephalopathy has lagged behind the vast knowledge that has been generated from basic studies. In this article, we critically assess matters that should be revisited, such as definition, classification, diagnosis and grading of hepatic encephalopathy, which are difficult to apply reproducibly using the current criteria. Many lines of investigation have confirmed that hepatic encephalopathy is irreversible in many patients and suggest the need for further studies focussing on mechanisms of neuronal injury and death, to guide future drug development for these patients. The clinical evidence behind using lactulose for all severities of hepatic encephalopathy, which is currently considered the standard of care, is poor and placebo-controlled trials for hepatic encephalopathy should be considered ethically sound. This expert opinion identifies current challenges in hepatic encephalopathy and highlights areas which require further debate and investigation in order to help advance the field both scientifically and clinically.

Hepatic encephalopathy

Hepatic encephalopathy (HE) is a prognostically relevant neuropsychiatric syndrome that occurs in the course of acute or chronic liver disease. Besides ascites and variceal bleeding, it is the most serious complication of decompensated liver cirrhosis. Ammonia and inflammation are major triggers for the appearance of HE, which in patients with liver cirrhosis involves pathophysiologically low-grade cerebral oedema with oxidative/nitrosative stress, inflammation and disturbances of oscillatory networks in the brain. Severity classification and diagnostic approaches regarding mild forms of HE are still a matter of debate. Current medical treatment predominantly involves lactulose and rifaximin following rigorous treatment of so-called known HE precipitating factors. New treatments based on an improved pathophysiological understanding are emerging.

Combined PEG3350 Plus Lactulose Results in Early Resolution of Hepatic Encephalopathy and Improved 28-Day Survival in Acute-on-Chronic Liver Failure

BACKGROUND AND AIMS

Acute-on-chronic liver failure (ACLF) is associated with high short-term mortality in those with hepatic encephalopathy (HE). Polyethylene glycol (PEG) 3350 electrolyte solution can ensure rapid gut catharsis, which may resolve HE more effectively than lactulose. In this open-label-randomized trial, we compared PEG+lactulose versus lactulose alone in ACLF with HE grade ≥2 for efficacy and outcome.

PATIENTS AND METHODS

Patients were randomized to receive PEG (2 L q12 h) followed by lactulose (30 mL q8 h) or standard medical treatment [SMT, lactulose (titrated 30 mL q8 h)]. Endpoints were HE grade improvement at 24 hours, 48 hours, and 7 days using hepatic encephalopathy scoring algorithm (HESA), ammonia reduction, HE resolution, and survival benefit.

RESULTS

Of 60 patients, 29 were randomized to PEG+lactulose arm and 31 to SMT. In the PEG arm, early reduction in HESA score was noted in more persons [18 (62.1%) vs. 10 (32.2%); P=0.021] with a shorter median time to HE resolution [4.5 (3 to 9) d vs. 9 (8 to 11) d; P=0.023]. On multivariate analysis, age [hazard ratio (HR),1.06 (1.00 to 1.13); P=0.03], HESA score [HR, 6.01 (1.27 to 28.5); P=0.024], and model for end-stage liver disease [HR, 1.26 (1.01 to 1.53); P=0.022] were predictors of mortality at 28 days. Ammonia level or reduction did not correlate with HE grades. Adverse events included excessive diarrhea (20.6% vs. 9.6%) in the PEG and SMT arms, albeit without dyselectrolytemia or worsened renal function. In the PEG versus SMT arm, survival at 28 days were 93.1% versus 67.7% (P=0.010) and at 90 days was 68.9% versus 48.3% (P=0.940), respectively, with fewer persons relapsing with HE in the PEG arm.

CONCLUSIONS

PEG resulted in early and sustained HE resolution with improved short-term survival making, it a suitable and safe drug in patients with acute HE in ACLF.

Desenvolvimento neuropsicomotor e habilidades funcionais em pré-escolares com doenças hepáticas

Resumo Introdução Crianças com doenças hepáticas crônicas são expostas a fatores de risco biológicos e/ou ambientais que podem comprometer suas aquisições neuromotoras e o desenvolvimento de suas habilidades funcionais. Objetivo Descrever o desenvolvimento neuropsicomotor (DNPM) e habilidades funcionais de crianças com doenças hepáticas crônicas. Métodos Estudo seccional, descritivo e exploratório realizado com crianças de até 6 anos, que foram selecionadas em um hospital de referência do estado da Bahia, Brasil, no período de novembro de 2019 a março de 2020. Foram consideradas elegíveis para o estudo crianças em atendimento ambulatorial, com diagnóstico clínico, laboratorial e histológico compatíveis com doença hepática crônica. O instrumento de avaliação do desenvolvimento neuropsicomotor foi o Denver II. As habilidades funcionais foram obtidas pela aplicação do Inventário de Avaliação Pediátrica de Incapacidade Testagem Computadorizada Adaptativa (PEDI-CAT) aos pais ou cuidadores principais, versão rápida (Speedy-CAT). Resultados Das 34 crianças com hepatopatias crônicas, 52,9% eram do sexo feminino, com idade entre 4 e 6 anos (64%). Os resultados do teste de Denver II demonstraram que 68,7% (22/32) da amostra apresentaram risco para DNPM. No PEDI-CAT, os escores das crianças hepatopatas com risco para DNPM foram de 60,7 ± 9,1 nos domínios atividade diária, 57,6 ± 11,8 em mobilidade e 48,3 ± 6,2 em social/cognitivo. Conclusão Crianças com hepatopatias crônicas apresentam risco para DNPM, apesar de não possuírem comprometimento de suas habilidades funcionais quando avaliadas pelo PEDI-CAT.

Renal and brain failure predict mortality of patients with acute-on-chronic liver failure admitted to the intensive care unit

INTRODUCTION AND OBJECTIVES

Acute on Chronic Liver Failure (ACLF) is characterized by organ failure and high 28-day mortality. Identifying clinical predictors associated with early mortality could have implications for the treatment of patients with ACLF.

PATIENTS AND METHODS

Patients diagnosed with chronic liver failure that developed ACLF based on the EASL-CLIF Consortium definition admitted to the Intensive care unit of a tertiary hospital between 2012-2018 were included. Bivariate and multivariate Cox regression analyses were performed to identify factors associated with mortality.

RESULTS

148 patients (55% female) were diagnosed with ACLF of which 55% (n = 82) had ACLF grade 3, 28% (n = 41) grade 2 and 17% (n = 25) grade 1. The median age was 54 years (41-63). Hepatitis C virus (HCV) was the most frequent etiology in 29.8% (n = 44) of the patients with bacterial infection being the most predominant precipitant factor in 58.1% (n = 86). Ninety-day global cumulative survival was only 18%. When divided by grade, mortality reached to 10% in ACLF 3. Moreover, in the multivariate Cox regression analysis, renal failure (HR 3.26, 95% CI (2.13-4.99), brain failure (HR 1.37, 95% CI 1.09-2.04) and male sex (HR 1.62, 95% CI 1.10-2.40) were independent predictors of 28- and 90-day mortality.

CONCLUSIONS

ACLF is a frequent syndrome among chronic liver disease patients. Brain and renal failure are significantly associated with higher mortality and are independent predictors of 28 and 90-day mortality.

Albumin Substitution in Decompensated Liver Cirrhosis: Don't Forget Zinc

Decompensated liver cirrhosis has a dismal prognosis, with patients surviving on average for 2-4 years after the first diagnosis of ascites. Albumin is an important tool in the therapy of cirrhotic ascites. By virtue of its oncotic properties, it reduces the risk of cardiovascular dysfunction after paracentesis. Treatment with albumin also counteracts the development of hepatorenal syndrome and spontaneous bacterial peritonitis. More recently, the positive impact of long-term albumin supplementation in liver disease, based on its pleiotropic non-oncotic activities, has been recognized. These include transport of endo- and exogenous substances, anti-inflammatory, antioxidant and immunomodulatory activities, and stabilizing effects on the endothelium. Besides the growing recognition that effective albumin therapy requires adjustment of the plasma level to normal physiological values, the search for substances with adjuvant activities is becoming increasingly important. More than 75% of patients with decompensated liver cirrhosis do not only present with hypoalbuminemia but also with zinc deficiency. There is a close relationship between albumin and the essential trace element zinc. First and foremost, albumin is the main carrier of zinc in plasma, and is hence critical for systemic distribution of zinc. In this review, we discuss important functions of albumin in the context of metabolic, immunological, oxidative, transport, and distribution processes, alongside crucial functions and effects of zinc and their mutual dependencies. In particular, we focus on the major role of chronic inflammatory processes in pathogenesis and progression of liver cirrhosis and how albumin therapy and zinc supplementation may affect these processes.

Therapeutic Applications of Resveratrol in Hepatic Encephalopathy through Its Regulation of the Microbiota, Brain Edema, and Inflammation

Hepatic encephalopathy is a common complication in patients with liver cirrhosis and portosystemic shunting. Patients with hepatic encephalopathy present a variety of clinical features, including neuropsychiatric manifestations, cognitive dysfunction, impaired gut barrier function, hyperammonemia, and chronic neuroinflammation. These pathogeneses have been linked to various factors, including ammonia-induced oxidative stress, neuronal cell death, alterations in the gut microbiome, astrocyte swelling, and blood-brain barrier disruptions. Many researchers have focused on identifying novel therapeutics and prebiotics in the hope of improving the treatment of these conditions. Resveratrol is a natural polyphenic compound and is known to exert several pharmacological effects, including antioxidant, anti-inflammatory, and neuroprotective activities. Recent studies suggest that resveratrol contributes to improving the neuropathogenic effects of liver failure. Here, we review the current evidence describing resveratrol's effects in neuropathogenesis and its impact on the gut-liver axis relating to hepatic encephalopathy. We highlight the hypothesis that resveratrol exerts diverse effects in hepatic encephalopathy and suggest that these effects are likely mediated by changes to the gut microbiota, brain edema, and neuroinflammation.

NEUROPSYCHOMOTOR DEVELOPMENT IN CHILDREN AND ADOLESCENTS WITH LIVER DISEASES: SYSTEMATIC REVIEW WITH META-ANALYSIS

BACKGROUND

The nature of liver disease, the evolutionary course and duration of liver diseases, as well as the degree of severity and disability can trigger multiple outcomes with repercussions on neuromotor acquisition and development.

OBJECTIVE

To systematically review and conduct a meta-analysis to evaluate the effects of liver disease on the neuropsychomotor development of children and adolescents with their native livers and those who underwent liver transplantation.

METHODS

Observational studies published since the early 1980s until June 2019 were sought in the PubMed and Scopus databases. An α value of 0.05 was considered significant. The statistical heterogeneity of the treatment effect between the studies was assessed by the Cochran's Q test and the I2 inconsistency test, in which values above 25 and 50% were considered indicative of moderate and high heterogeneity, respectively. Analyses were performed with Review Manager 5.3.

RESULTS

Twenty-five studies met the eligibility criteria, including 909 children and adolescents with liver disease. Meta-analyses showed deficits in total IQ -0.41 (95%CI: -0.51 to -0.32; N: 9,973), verbal IQ -0.38 (95%CI: -0.57 to -0.18; N: 10,284) and receptive language -0.85 (95%CI: -1.16 to -0.53; N: 921) in liver transplantation, and those with native livers who had symptoms early had total and verbal IQ scores (85±8.8; 86.3±10.6 respectively) lower than the scores of those with late manifestations (99.5±13.8; 96.2±9.2). Gross motor skill was reduced -46.29 (95%CI: -81.55 to -11.03; N: 3,746).

CONCLUSION

Acute or chronic liver disease can cause declines in cognitive, motor and language functions. Although the scores improve after liver transplantation, children remain below average when compared to healthy children.

Dynamic assessments of hepatic encephalopathy and ammonia levels predict mortality in acute-on-chronic liver failure

BACKGROUND

We evaluated the dynamics of hepatic encephalopathy (HE) and ammonia estimation in acute-on-chronic liver failure (ACLF) patients due to a paucity of evidence.

METHODS

ACLF patients recruited from the APASL-ACLF Research Consortium (AARC) were followed up till 30 days, death or transplantation, whichever earlier. Clinical details, including dynamic grades of HE and laboratory data, including ammonia levels, were serially noted.

RESULTS

Of the 3009 ACLF patients, 1315 (43.7%) had HE at presentation; grades I-II in 981 (74.6%) and grades III-IV in 334 (25.4%) patients. The independent predictors of HE at baseline were higher age, systemic inflammatory response, elevated ammonia levels, serum protein, sepsis and MELD score (p < 0.05; each). The progressive course of HE was noted in 10.0% of patients without HE and 8.2% of patients with HE at baseline, respectively. Independent predictors of progressive course of HE were AARC score (≥ 9) and ammonia levels (≥ 85 μmol/L) (p < 0.05; each) at baseline. A final grade of HE was achieved within 7 days in 70% of patients and those with final grades III-IV had the worst survival (8.9%). Ammonia levels were a significant predictor of HE occurrence, higher HE grades and 30-day mortality (p < 0.05; each). The dynamic increase in the ammonia levels over 7 days could predict nonsurvivors and progression of HE (p < 0.05; each). Ammonia, HE grade, SIRS, bilirubin, INR, creatinine, lactate and age were the independent predictors of 30-day mortality in ACLF patients.

CONCLUSIONS

HE in ACLF is common and is associated with systemic inflammation, poor liver functions and high disease severity. Ammonia levels are associated with the presence, severity, progression of HE and mortality in ACLF patients.

Pathophysiology of decompensated cirrhosis: Portal hypertension, circulatory dysfunction, inflammation, metabolism and mitochondrial dysfunction

Patients with acutely decompensated cirrhosis have a dismal prognosis and frequently progress to acute-on-chronic liver failure, which is characterised by hepatic and extrahepatic organ failure(s). The pathomechanisms involved in decompensation and disease progression are still not well understood, and as specific disease-modifying treatments do not exist, research to identify novel therapeutic targets is of the utmost importance. This review amalgamates the latest knowledge on disease mechanisms that lead to tissue injury and extrahepatic organ failure - such as systemic inflammation, mitochondrial dysfunction, oxidative stress and metabolic changes - and marries these with the classical paradigms of acute decompensation to form a single paradigm. With this detailed breakdown of pathomechanisms, we identify areas for future research. Novel disease-modifying strategies that break the vicious cycle are urgently required to improve patient outcomes.

Role of ammonia in predicting the outcome of patients with acute-on-chronic liver failure

BACKGROUND

High venous ammonia (VA) values have been proven to be a part of the mechanism of hepatic encephalopathy in patients with liver cirrhosis (LC) as well as acute hepatitis. Moreover, VA has been associated with poor prognosis and high mortality in these clinical settings. However, the role of ammonia in acute-on-chronic liver failure (ACLF) has not yet been clearly established.

AIM

To assess the role of VA in predicting the outcome of cirrhotic patients with ACLF in a tertiary care center.

METHODS

We performed a retrospective observational study including consecutive patients with LC hospitalized for acute non-elective indications such as ascites, hepatic encephalopathy (HE), upper gastrointestinal bleeding, or bacterial infections that fulfilled the Asian Pacific Association for the Study of the Liver (APASL) criteria for ACLF. The study was conducted in “St. Spiridon” University Hospital, Iasi, Romania, a tertiary care center, between January 2017 and January 2019. The APASL ACLF Research Consortium (AARC) score was calculated and ACLF grade was established accordingly. West-haven classification was used for HE. Statistical analysis was performed using IBM SPSS version 22.0.

RESULTS

Four hundred and forty-six patients were included, aged 59 (50-65) years, 57.4% men. Child-Pugh, model for end-stage liver disease (MELD) and AARC scores were 11 (10-12), 19.13 ± 6.79, and 7 (6-8), respectively. 66.4% had ACLF grade I, 31.2% ACLF grade II, and 2.5% ACLF grade III. HE was diagnosed in 83.9%, 34% grade I, 37.2% grade II, 23.5% grade III, and 5.3% grade IV. Overall mortality was 7.8%. VA was 103 (78-148) μmol/L. Receiver operating characteristic analysis showed good accuracy for the prediction of in-hospital mortality for the AARC score [Area under the curve (AUC) = 0.886], MELD score (AUC = 0.816), VA (AUC = 0.812) and a fair accuracy for the Child-Pugh score (AUC = 0.799). Subsequently, a cut-off value for the prediction of mortality was identified for VA (152.5 μmol/L, sensitivity = 0.706, 1-specificity = 0.190). Univariate analysis found acute kidney injury, severe HE (grade III or IV), VA ≥ 152.5 μmol/L, MELD score ≥ 22.5, Child-Pugh score ≥ 12.5, and AARC score ≥ 8.5 to be associated with in-hospital mortality. Multivariate analysis identified AARC score ≥ 8.5 and venous ammonia ≥ 152 μmol/L to be independent predictors of in-hospital mortality.

CONCLUSION

VA could be used as an inexpensive predictor of in-hospital mortality in patients with ACLF. Patients with both ACLF and VA > 152.5 μmol/L have a high risk for a poor outcome.

Hepatic encephalopathy: Novel insights into classification, pathophysiology and therapy

Hepatic encephalopathy (HE) is a frequent and serious complication of both chronic liver disease and acute liver failure. HE manifests as a wide spectrum of neuropsychiatric abnormalities, from subclinical changes (mild cognitive impairment) to marked disorientation, confusion and coma. The clinical and economic burden of HE is considerable, and it contributes greatly to impaired quality of life, morbidity and mortality. This review will critically discuss the latest classification of HE, as well as the pathogenesis and pathophysiological pathways underlying the neurological decline in patients with end-stage liver disease. In addition, management strategies, diagnostic approaches, currently available therapeutic options and novel treatment strategies are discussed.

Hepatic Encephalopathy-Associated Cerebral Vasculopathy in Acute-on-Chronic Liver Failure: Alterations on Endothelial Factor Release and Influence on Cerebrovascular Function

The acute-on-chronic liver failure (ACLF) is a syndrome characterized by liver decompensation, hepatic encephalopathy (HE) and high mortality. We aimed to determine the mechanisms implicated in the development of HE-associated cerebral vasculopathy in a microsurgical liver cholestasis (MHC) model of ACLF. Microsurgical liver cholestasis was induced by ligating and extracting the common bile duct and four bile ducts. Sham-operated and MHC rats were maintained for eight postoperative weeks Bradykinin-induced vasodilation was greater in middle cerebral arteries from MHC rats. Both Nω-Nitro-L-arginine methyl ester and indomethacin diminished bradykinin-induced vasodilation largely in arteries from MHC rats. Nitrite and prostaglandin (PG) F_1α releases were increased, whereas thromboxane (TX) B₂ was not modified in arteries from MHC. Expressions of endothelial nitric oxide synthase (eNOS), inducible NOS, and cyclooxygenase (COX) 2 were augmented, and neuronal NOS (nNOS), COX-1, PGI₂ synthase, and TXA₂S were unmodified. Phosphorylation was augmented for eNOS and unmodified for nNOS. Altogether, these endothelial alterations might collaborate to increase brain blood flow in HE.

Serum ammonia is a strong prognostic factor for patients with acute-on-chronic liver failure

Ammonia is thought to be central to the pathogenesis of hepatic encephalopathy (HE), but its prognostic role in acute-on-chronic liver failure (ACLF) is still unknown. We aimed to determine the association between serum ammonia level and short-term prognosis in ACLF. Furthermore, we performed an in-depth evaluation of the independent effect of serum ammonia level on the short-term prognosis of hepatitis B virus (HBV) reactivation-induced ACLF patients. We identified 174 patients as part of prospective observational studies in patients with ACLF. Plasma ammonia levels were measured on admission, and several prognostic scores were used to determine the prognostic effect of ammonia. The 28-day patient survival was determined. Receiver operating characteristic analysis was used to identify the cut-off points for ammonia values, and multivariable analysis was performed using the Cox proportional hazard regression model. Plasma ammonia was significantly higher in nonsurvivors (83.53 ± 43.78 versus 67.13 ± 41.77 µmol/L, P = 0.013), and ACLF patients with hyperammonemia had significantly higher 28-day mortality than those without hyperammonemia. Ammonia was also closely related to ACLF grade (P < 0.001) and organ failure, including liver (P = 0.048), coagulation (P < 0.001) and brain (P < 0.001). HBV reactivation serves as the main precipitating factor in the ACLF population. Subgroup analysis showed that ammonia is also a strong prognostic factor in the HBV reactivation-induced ACLF population. Ammonia level is closely correlated with failure of other organs and is an independent risk factor for mortality in ACLF and the special population defined as HBV reactivation-related ACLF. Based on the results from our study, we measured serum ammonia in the population with ACLF, which strongly indicates their prognosis. It serves as an important biomarker and a therapeutic target.

Ammonia predicts poor outcomes in patients with hepatitis B virus-related acute-on-chronic liver failure

BACKGROUND

Hepatic encephalopathy (HE) is a common feature of acute liver failure and has been reported to be associated with poor outcomes. Ammonia is thought to be central to the pathogenesis of HE, but its role in hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is unclear. The present study aimed to assess the prognostic role of ammonia level for patients with HBV-ACLF.

METHODS

We retrospectively recruited 127 patients diagnosed with HBV-ACLF for the present study.

RESULTS

Ammonia levels at the time of admission were higher among non-surviving participants than in survivors. Increased ammonia level was found to be associated with severe liver disease and was identified as an independent predictor for mortality in patients with HBV-ACLF.

CONCLUSIONS

Our results suggest that high ammonia level at admission is an independent factor for predicting short-term mortality in patients with HBV-ACLF. Therefore, ammonia levels may represent a therapeutic target for this condition.

Neuroprotective effect of 25-Methoxyhispidol A against CCl4-induced behavioral alterations by targeting VEGF/BDNF and caspase-3 in mice

Brain oxidative stress and neuroinflammation have been implicated in various psychiatric disorders. The current study investigated the effect and mechanism of 25-Methoxyhispidol A (25-MHA) against CCl₄-induced anxiety and depression. Mice were challenged with CCl₄ (1 ml/kg; i.p.) after 30 min of 25-MHA (1, 5 and 10 mg/kg; i.p.) administration. Pretreatment with 25-MHA (10 mg/kg) significantly attenuated the anxiety and depression-like behavior in testing models. The oxidative stress induced by CCl₄ was significantly attenuated by pretreatment with 25-MHA. The immunohistochemical (IHC) analysis showed a reduction in kelch-like ECH-associated protein 1 (Keap1) and improvement in expression of nuclear factor erythroid-2-related factor (Nrf-2) and heme oxygenase (HO)-1. In addition, 25-MHA significantly attenuated the CCl₄-mediated depletion of antioxidant enzymes in hippocampus (HC) and prefrontal cortex (PFC) region and reduced the expression of toll-like receptor (TLR)-4 and nuclear factor kappa B (NF-κB), along with a decreased production of pro-inflammatory cytokines in HC and PFC region. Pretreatment with 25-MHA also showed an improved expression of neurotrophic factors i.e., brain derived growth factor (BDNF) and vascular endothelial growth factor (VEGF). Furthermore, 25-MHA inhibited malondialdehyde (MDA) and ammonia level in plasma, liver, HC and PFC regions of mice brain. 25-MHA also exhibited anti-apoptotic effect evident from the reduced expression of caspase-3 and decreased hippocampal DNA damage in comet assay. Furthermore, decreased serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and corticosterone level, along with prevention of CCl₄-induced alterations in thickness of dentate gyrus and intact hepatic cells morphology, represented by hippocampal and liver histopathology, indicated the neuroprotective effect of 25-MHA.

Persistent or incident hyperammonemia is associated with poor outcomes in acute decompensation and acute-on-chronic liver failure

Background and Aim

The effect of elevated ammonia on organ failures (OF), apart from hepatic encephalopathy, in patients with acute decompensation (AD) of cirrhosis and acute‐on‐chronic liver failure (ACLF) is unclear. We aimed to assess the effect of persistent or incident hyperammonemia on OF and outcomes in patients with AD and ACLF.

Methods

A total of 229 patients with ACLF and 83 with AD were included. Arterial ammonia was measured on day 1 and day 3 of admission. Persistent or incident hyperammonemia was defined as a level of ≥79.5 μmol/L on day 3. The changes in ammonia levels during the first 3 days were analyzed with respect to the complications and outcomes.

Results

At admission, the median level of arterial ammonia was higher in ACLF compared to AD patients (103 vs 86 μmol/L, P < 0.001). Persistent or incident hyperammonemia was noted in 206 (66.0%) patients and was more frequent in ACLF compared to AD patients (70.7 vs 53.0%, P = 0.013). Patients with persistent or incident hyperammonemia, compared to those without it, developed a higher proportion of new‐onset OF during hospitalization involving liver (P = 0.018), kidney (P = 0.001), brain (P = 0.005), coagulation (P = 0.036), circulation (P = 0.002), and respiratory (P = 0.003) issues and had higher 28‐day mortality (log‐rank test, P < 0.001). After adjustment for chronic liver failure consortium ACLF score, persistent or incident hyperammonemia (hazard ratio, 3.174) was independently associated with 28‐day mortality. The presence of infection was an independent predictor of persistent or incident hyperammonemia.

Conclusion

Persistent or incident hyperammonemia during first 3 days of hospitalization in patients with AD or ACLF is associated with increased risk of OF and death.

The Direct Contribution of Astrocytes and Microglia to the Pathogenesis of Hepatic Encephalopathy

Hepatic encephalopathy is a neurological complication resulting from loss of hepatic function and is associated with poor clinical outcomes. During acute liver failure over 20% of mortality can be associated with the development of hepatic encephalopathy. In patients with liver cirrhosis, 1-year survival for those that develop overt hepatic encephalopathy is under 50%. The pathogenesis of hepatic encephalopathy is complicated due to the multiple disruptions in homeostasis that occur following a reduction in liver function. Of these, elevations of ammonia and neuroinflammation have been shown to play a significant contributing role to the development of hepatic encephalopathy. Disruption of the urea cycle following liver dysfunction leads to elevations of circulating ammonia, which enter the brain and disrupt the functioning of astrocytes. This results in dysregulation of metabolic pathways in astrocytes, oxidative stress and cerebral edema. Besides ammonia, circulating chemokines and cytokines are increased following liver injury, leading to activation of microglia and a subsequent neuroinflammatory response. The combination of astrocyte dysfunction and microglia activation are significant contributing factors to the pathogenesis of hepatic encephalopathy.

Prognostic Role of Ammonia in Patients With Cirrhosis

Ammonia is thought to be central to the pathogenesis of hepatic encephalopathy (HE), but its prognostic role in patients with cirrhosis and acute decompensation is unknown. The aims of this study were to determine the relationship between ammonia levels and severity of HE and its association with organ dysfunction and short-term mortality. We identified 498 patients from two institutions as part of prospective observational studies in patients with cirrhosis. Plasma ammonia levels were measured on admission and Chronic Liver Failure-Sequential Organ Failure Assessment criteria were used to determine the presence of organ failures. The 28-day patient survival was determined. Receiver operating characteristic analysis was used to identify the cutoff points for ammonia values, and multivariable analysis was performed using the Cox proportional hazard regression model. The 28-day mortality was 43.4%. Plasma ammonia correlated with severity of HE (P < 0.001), was significantly higher in nonsurvivors (93 [73-121] versus 67 [55-89] µmol/L, P < 0.001), and was an independent predictor of 28-day mortality (hazard ratio, 1.009, P < 0.001). An ammonia level of 79.5 µmol/L had sensitivity of 68.1% and specificity of 67.4% for predicting 28-day mortality. An ammonia level of ≥79.5 µmol/L was associated with a higher frequency of organ failures (liver [P = 0.004], coagulation [P < 0.001], kidney [P = 0.004], and respiratory [P < 0.001]). Lack of improvement in baseline ammonia at day 5 was associated with high mortality (70.6%). Conclusion: Ammonia level correlates with not only the severity of HE but also the failure of other organs and is an independent risk factor for mortality; lack of improvement in ammonia level is associated with high risk of death, making it an important biomarker and a therapeutic target.

Targeted puncture of left branch of intrahepatic portal vein in transjugular intrahepatic portosystemic shunt to reduce hepatic encephalopathy

BACKGROUND

Transjugular intrahepatic portosystemic shunt (TIPS) is currently used for the treatment of complications of portal hypertension. The incidence of hepatic encephalopathy (HE) remains a problem in TIPS placement. It has been reported that the right branch mainly receives superior mesenteric venous blood while the left branch mainly receives blood from the splenic vein. We hypothesized that targeted puncture of the left portal vein would divert the non-nutritive blood from the splenic vein into the TIPS shunt; therefore, targeted puncture of the left branch of the intrahepatic portal vein during TIPS may reduce the risk of HE.

AIM

To evaluate the influence of targeted puncture of left branch of portal vein in TIPS on HE.

METHODS

A retrospective analysis of 1244 patients with portal-hypertension-related complications of refractory ascites or variceal bleeding who underwent TIPS from January 2000 to January 2013 was performed. Patients were divided into group A (targeting left branch of portal vein, n = 937) and group B (targeting right branch of portal vein, n = 307). TIPS-related HE and clinical outcomes were analyzed.

RESULTS

The symptoms of ascites and variceal bleeding disappeared within a short time. By the endpoint of follow-up, recurrent bleeding and ascites did not differ significantly between groups A and B (P = 0.278, P = 0.561, respectively). Incidence of HE differed significantly between groups A and B at 1 mo (14.94% vs 36.80%, χ² = 4.839, P = 0.028), 3 mo (12.48% vs 34.20%, χ² = 5.054, P = 0.025), 6 mo (10.03% vs 32.24%, χ² = 6.560, P = 0.010), 9 mo (9.17% vs 31.27%, χ² = 5.357, P = 0.021), and 12 mo (8.21% vs 28.01, χ² = 3.848, P = 0.051). There were no significant differences between groups A and B at 3 years (6.61% vs 7.16%, χ² = 1.204, P = 0.272) and 5 years (5.01% vs 6.18%, χ² = 0.072, P = 0.562). The total survival rate did not differ between groups A and B (χ² = 0.226, P = 0.634, log-rank test).

CONCLUSION

Targeted puncture of the left branch of the intrahepatic portal vein during TIPS may reduce the risk of HE but has no direct influence on prognosis of portal-hypertension-related complications.

Hepatic encephalopathy 2018: A clinical practice guideline by the Italian Association for the Study of the Liver (AISF)

Hepatic encephalopathy (HE) is a common, worrisome and sometimes difficult to manage complication of end-stage liver disease. HE is often recurrent, requiring multiple hospital admissions. It can have serious implications in terms of a patient's ability to perform complex tasks (for example driving), their earning capacity, their social and family roles. This guideline reviews current knowledge on HE definition, pathophysiology, diagnosis and treatment, both by general principles and by way of a summary of available drugs and treatment strategies. The quality of the published, pertinent evidence is graded, and practical recommendations are made. Where possible, these are placed within the Italian health service context, with reference to local diagnosis and management experience.

Current Diagnosis and Classification of Hepatic Encephalopathy

Hepatic encephalopathy is a brain dysfunction caused by liver insufficiency and/or portal-systemic shunt; it manifests as a wide spectrum of neurological or psychiatric abnormalities ranging from subclinical alterations to coma. It should be differentiated from other neurological/psychiatric disorders that can occur in patients with liver disease. Its classification needs to take into account the underlying condition, severity, course, precipitating factors, and-possibly-sensitivity to ammonia-lowering agents.

Resveratrol Restores Neuronal Tight Junction Proteins Through Correction of Ammonia and Inflammation in CCl4-Induced Cirrhotic Mice

Systemic inflammation and ammonia (hyperammonemia) act synergistically in the pathogenesis of hepatic encephalopathy (HE), the neurobehavioral sequelae of advanced liver disease. In cirrhotic patients, we have recently observed elevated levels of circulating neuronal tight junction (TJ) protein, zonula occludens 1 (ZO-1), reflective of a change to blood-brain barrier (BBB) integrity. Moreover, ZO-1 levels positively correlated with hyperammonemia, although any potential relationship remains unclear. Using a carbon tetrachloride (CCl₄)-induced mouse model of cirrhosis, we primarily looked to explore the relationship between neuronal TJ protein expression and hyperammonemia. Secondarily, we assessed the potential role of a natural antioxidant, resveratrol, on neuronal TJ protein expression and hyperammonemia. Over 12 weeks, male Swiss mice were randomized (n = 8/group) to either naïve controls or induced cirrhosis, using two doses of intraperitoneal CCl₄ (0.5 ml/kg/week). After 12 weeks, naïve and cirrhotic mice were randomized to receive either 2 weeks of par-oral resveratrol (10 mg/kg). Plasma samples were analyzed for ammonia, liver biochemistry (ALT, AST, albumin, and bilirubin), and pro-inflammatory cytokines (TNF-α and IL-1β), and brain tissue for brain water content, TJ protein expression (e.g., ZO-1, claudin 5, and occludin), and tissue oxidative stress and inflammatory markers (NF-κB and iNOS) using western blotting. Compared to naïve mice, cirrhosis significantly increased circulating ammonia, brain water, ALT, AST, TNF-α, IL-1β, 4HNE, NF-κB, and iNOS levels, with a concomitant reduction in all TJ proteins (P < 0.05, respectively). In cirrhotic mice, resveratrol treatment ameliorated these changes significantly (P < 0.05, respectively). Our findings provide evidence for a causal association between hyperammonemia and inflammation in cirrhosis linked to TJ protein alterations, BBB disruption, and HE predilection. Moreover, this is the first report of a potential role for resveratrol as a novel therapeutic approach to managing neurological sequelae complicating cirrhosis.

Gene Therapy for Treatment of Chronic Hyperammonemia in a Rat Model of Hepatic Encephalopathy

INTRODUCTION AND AIM

Hepatic encephalopathy (HE), caused by hyperammonemia resulting from liver disease, is a spectrum of neuropsychiatric and motor disorders that can lead to death. Existing therapies are deficient and alternative treatments are needed. We have shown that gene therapy with a baculovirus vector containing the glutamine synthetase (Bac-GS) gene is efficient for reducing ammonia levels in an acute hyperammonemia rat model. However, the most common condition resulting from liver disease is chronic hyperammonemia. In this work, Bac-GS was evaluated in bile-duct ligated rats, a chronic liver disease model with hyperammonemia and some characteristics of Type C HE.

MATERIAL AND METHODS

Bac-GS was tested for mediating GS overexpression in HeLa cells and H9C2 myotubes. For determining the utility of Bac-GS for the reduction of ammonia levels in a chronic hyperammonemia animal model, four groups of rats were treated: control, sham, ligated with Bac-GS and ligated with Bac-GFP. Baculoviruses were injected i.m. 18 days post-surgery. Blood was drawn 2, 3 and 4 weeks post-surgery and plasma ammonia concentrations were quantified.

RESULTS

In protein lysates of cells and myotubes transduced with Bac-GS, a 44 kDa band corresponding to GS was detected. Significant results were obtained in the hyperammonemic bile-duct ligated rat model, as plasma ammonia was reduced to normal levels 3 days after treatment with Bac-GS. Furthermore, a transitory effect of Bac-GS was observed.

CONCLUSION

Our results show that gene therapy by delivering GS is a promising alternative for treatment of hyperammonemia in acute-on-chronic liver failure patients with HE.

Validation of CLIF-C ACLF score to define a threshold for futility of intensive care support for patients with acute-on-chronic liver failure

Background

Acute-on-chronic liver failure (ACLF) is a severe complication of cirrhosis and is defined by organ failure and high rates of short-term mortality. Patients with ACLF are managed with multiorgan support in the intensive care unit (ICU). Currently, it is unclear when this supportive care becomes futile, particularly in patients who are not candidates for liver transplant. The aim of this study was to determine whether the currently available prognostic scores can identify patients with ACLF in whom prolonged ICU care is likely to be futile despite maximal treatment efforts.

Methods

Data of 202 consecutive patients with ACLF admitted to the ICU at the Royal Free Hospital London between 2005 and 2012 were retrospectively analyzed. Prognostic scores for chronic liver diseases, such as Child-Pugh, Model for End-Stage Liver Disease (MELD), European Foundation for the study of chronic liver failure (CLIF-C) organ failure (OF), and CLIF-C ACLF, were calculated 48 hours after ICU admission and correlated with patient outcome after 28 days.

Results

The CLIF-C ACLF score, compared with all other scores, most accurately predicted 28-day mortality, with an area under the receiver operator characteristic of 0.8 (CLIF-C OF, 0.75; MELD, 0.68; Child-Pugh, 0.66). A CLIF-C ACLF score cutoff ≥ 70 identified patients with a 100% mortality within 28 days. These patients had elevated inflammatory parameters representing a systemic inflammatory response, most often renal failure, compared with patients below this cutoff.

Conclusions

Patients with ACLF and high CLIF-C ACLF score (≥ 70) after 48 hours of intensive care may reach a threshold of futility for further ongoing intensive support. The best treatment options in this scenario remain to be determined but may include palliative care.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-2156-0) contains supplementary material, which is available to authorized users.

Ammonia mediates cortical hemichannel dysfunction in rodent models of chronic liver disease

The pathogenesis of hepatic encephalopathy (HE) in cirrhosis is multifactorial and ammonia is thought to play a key role. Astroglial dysfunction is known to be present in HE. Astrocytes are extensively connected by gap junctions formed of connexins, which also exist as functional hemichannels allowing exchange of molecules between the cytoplasm and the extracellular milieu. The astrocyte-neuron lactate shuttle hypothesis suggests that neuronal activity is fueled (at least in part) by lactate provided by neighboring astrocytes. We hypothesized that in HE, astroglial dysfunction could impair metabolic communication between astrocytes and neurons. In this study, we determined whether hyperammonemia leads to hemichannel dysfunction and impairs lactate transport in the cerebral cortex using rat models of HE (bile duct ligation [BDL] and induced hyperammonemia) and also evaluated the effect of ammonia-lowering treatment (ornithine phenylacetate [OP]). Plasma ammonia concentration in BDL rats was significantly reduced by OP treatment. Biosensor recordings demonstrated that HE is associated with a significant reduction in both tonic and hypoxia-induced lactate release in the cerebral cortex, which was normalized by OP treatment. Cortical dye loading experiments revealed hemichannel dysfunction in HE with improvement following OP treatment, while the expression of key connexins was unaffected.

CONCLUSION

The results of the present study demonstrate that HE is associated with central nervous system hemichannel dysfunction, with ammonia playing a key role. The data provide evidence of a potential neuronal energy deficit due to impaired hemichannel-mediated lactate transport between astrocytes and neurons as a possible mechanism underlying pathogenesis of HE. (Hepatology 2017;65:1306-1318).

Metabolomics Analysis Revealed Distinct Cyclic Changes of Metabolites Altered by Chronic Ethanol-Plus-Binge and Shp Deficiency

BACKGROUND

Chronic ethanol (EtOH) consumption causes alcoholic liver disease (ALD), and disruption of the circadian system facilitates the development of ALD. Small heterodimer partner (SHP) is a nuclear receptor and critical regulator of hepatic lipid metabolism. This study aimed at depicting circadian metabolomes altered by chronic EtOH-plus-binge and Shp deficiency using high-throughput metabolomics.

METHODS

Wild-type (WT) C57BL/6 and Shp^-/- mice were fed the control diet (CD) or Lieber-DeCarli EtOH liquid diet (ED) for 10 days followed by a single bout of maltose (CD + M) or EtOH (ED + E) binge on the 11th day. Serum and liver were collected over a 24-hour light/dark (LD) cycle at Zeitgeber time ZT12, ZT18, ZT0, and ZT6, and metabolomics was performed using gas chromatography-mass spectrometry.

RESULTS

A total of 110 metabolites were identified in liver and of those 80 were also present in serum from pathways of carbohydrates, lipids, pentose phosphate, amino acids, nucleotides, and tricarboxylic acid cycle. In the liver, 91% of metabolites displayed rhythmicity with ED + E, whereas in the serum, only 87% were rhythmic. Bioinformatics analysis identified unique metabolome patterns altered in WT CD + M, WT ED + E, Shp^-/- CD + M, and Shp^-/- ED + E groups. Specifically, metabolites from the nucleotide and amino acid pathway (ribose, glucose-6-phosphate, glutamic acid, aspartic acid, and sedoheptulose-7-P) were elevated in Shp^-/- CD + M mice during the dark cycle, whereas metabolites including N-methylalanine, 2-hydroxybutyric acid, and 2-hydroxyglutarate were elevated in WT ED + E mice during the light cycle. The rhythmicity and abundance of other individual metabolites were also significantly altered by both control and EtOH diets.

CONCLUSIONS

Metabolomics provides a useful means to identify unique metabolites altered by chronic EtOH-plus-binge.