Acute-on-chronic liver failure: current concepts on definition, pathogenesis, clinical manifestations and potential therapeutic interventions

Cross-sectional and dynamic change of serum metabolite profiling for Hepatitis B-related acute-on-chronic liver failure by UPLC/MS

Summary Acute-on-chronic liver failure(ACLF) is an increasingly recognized entity encompassing an acute deterioration of liver function and results in the failure of one or more organs with high short-term mortality. The focus of this study was to discover noninvasive and reliable biomarkers for the diagnosis and prognosis of hepatitis B-related ACLF. Ultra-performance liquid chromatography-mass spectrometry (UPLC/MS) was used to analyse serum metabolites of 28 patients with hepatitis B-related ACLF, 35 patients with Child-Pugh A cirrhosis, 30 patients with chronic hepatitis B and 35 healthy volunteers (HS). Characteristic metabolites were screened, identified and dynamically tracked to investigate their value for diagnosis and prognosis. After comparing serum metabolic profile of hepatitis B-related ACLF and Child-Pugh A cirrhosis, 99 characteristic metabolites were selected, and 38 of them were identified. Dynamic tracking model demonstrated that 17 metabolites were related to prognosis of hepatitis B-related ACLF, and there were also 11 metabolites which improved with treatment in the survival group. The correlations between these characteristic metabolites and the model for end-stage liver disease score were strong. These observations contributed to the investigation of the mechanisms of hepatitis B-related ACLF manifestation and progression on the metabolic level, and they provided information for the identification of biomarkers for the diagnosis and prognosis of hepatitis B-related ACLF.

Nucleoside analogs prevent disease progression in HBV-related acute-on-chronic liver failure: validation of the TPPM model

PURPOSE

This study aimed to evaluate the efficacy and safety of entecavir, lamivudine and telbivudine for treating patients with HBV-ACLF and to validate the Tongji prognostic predictor model (TPPM) in these patients.

METHODS

In this retrospective study, we enrolled 283 patients with HBV-ACLF (100 treated with entecavir, 98 treated with lamivudine and 85 treated with telbivudine). There were no significant differences in baseline clinical and virological characteristics among patients treated with entecavir, telbivudine or lamivudine.

RESULTS

There were no significant differences in the 4- and 12-week survival rates of entecavir-, telbivudine- and lamivudine-treated patients (79.00, 81.18 and 86.73 %, respectively, at 4 weeks; 67.00, 65.88 and 73.47 %, respectively, at 12 weeks). Patients in all three groups achieved an improvement in the model for end-stage liver disease (MELD) score. Using the Hosmer-Lemeshow test, the validation of the TPPM score for HBV-ACLF demonstrated a good degree of fit with disease prognosis. Based on this unique group of patients, the TPPM score with an AUC of 0.787 was superior to the MELD score, which had an AUC of 0.736 in the prediction of 12-week mortality. The TPPM had an AUC of 0.733, and the MELD score had an AUC of 0.672 in the prediction of 4-week mortality. Using a cutoff value of 0.22 for 12-week mortality prediction by the TPPM, the positive predictive value was 49.66 %, with a negative predictive value of 89.55 %.

CONCLUSION

Treatment with nucleoside analogs including entecavir, lamivudine and telbivudine prevented disease progression and increased the survival of patients with HBV-ACLF. Validation of the established TPPM scoring system in this study confirmed its superior predictive value for HBV-ACLF patients when compared with the MELD system.

Imbalance between circulating CD4+ regulatory T and conventional T lymphocytes in patients with HBV-related acute-on-chronic liver failure

BACKGROUND & AIMS

The important pathophysiological role of immune dysfunction, especially innate immune dysfunction in patients with acute-on-chronic liver failure (ACLF), has been investigated in recent years, but dysregulation of adaptive immunity remains poorly elucidated. The aim of this study was to (i) determine the CD3(+) T-lymphocyte count and the balance between CD4(+) regulatory T (Tregs) and conventional T cells (Tconv) in hepatitis B virus (HBV)-related ACLF patients; (ii) analyse the frequencies of Tregs subpopulations; and (iii) assess the suppressive potency of CD4(+) Tregs and each fraction.

METHODS

We enrolled 20 HBV-ACLF patients, 10 septic shock subjects, 20 chronic hepatitis B (CHB) patients and 20 healthy volunteers (HC). Based on flow cytometry, we performed the absolute counting of circulating T lymphocytes and phenotyping of CD4(+) Tregs and quantified the effects of Tregs and each subpopulation on Tconv proliferation by CFSE staining.

RESULTS

Compared with CHB patients and HC, we observed an equal reduction in peripheral T subsets in HBV-ACLF and septic shock subjects; the number of CD4(+) Tregs remained unchanged and the Tconv count declined, promoting elevation of the Treg-to-Tconv ratio. The frequencies of Treg-II and -III were elevated in HBV-ACLF. Functional studies showed that the suppressive capacity of Tregs was preserved in the HBV-ACLF group and Treg-II came first.

CONCLUSIONS

Similar to septic shock subjects, in HBV-ACLF patients there exists a reduction in CD4(+) T lymphocytes, predominantly CD4(+) Tconv, and the development of suppressive CD4(+) Tregs greatly prevails over Tconv, constituting important characteristics of adaptive immune dysfunction of HBV-ACLF.

Acute kidney injury in acute liver failure: a review

Acute liver failure is a rare and often devastating condition consequent on massive liver cell necrosis that frequently affects young, previously healthy individuals resulting in altered cognitive function, coagulopathy and peripheral vasodilation. These patients frequently develop concurrent acute kidney injury (AKI). This abrupt and sustained decline in renal function, through a number of pathogenic mechanisms such as renal hypoperfusion, direct drug-induced nephrotoxicity or sepsis/systemic inflammatory response contributes to increased morbidity and is strongly associated with a worse prognosis. Improved understanding of the pathophysiology AKI in the context of acute liver failure may be beneficial in a number of areas; the development of new and sensitive biomarkers of renal dysfunction, refining prognosis and organ allocation, and ultimately leading to the development of novel treatment strategies, these issues are discussed in more detail in this expert review.

Liver transplantation in lymphoma patients with hepatitis B virus reactivation

BACKGROUND

Acute-on-chronic liver failure (AoCLF) occurs in lymphoma patients because of hepatitis B virus (HBV) reactivation. We aimed to identify characteristics of patients who underwent liver transplantation (OLT) because of AoCLF that occurred due to HBV reactivation in the setting of lymphoma and to compare these patients with AoCLF patients who did not have lymphoma.

METHODS

Twenty patients underwent OLT due to AoCLF between February 2009 and June 2011. Among these patients, five were diagnosed with lymphoma before OLT and assigned to group 1. The remaining patients (n = 15) were assigned to group 2.

RESULTS

Hospitalization after transplantation in group 2 was longer than in group 1 (P = .014). However, there were no differences in other variables between the two groups. The overall survival rate of group 1 was lower than that of group 2, but there was no difference between the two groups (P = .134). With the exception of one patient, the median time from complete remission to liver transplantation in group 1 was 4.5 months (range, 1-15) in group 1. Lymphoma recurrence occurred in one patient 8 months after transplantation.

CONCLUSION

Our study revealed that OLT is a feasible and effective approach in AoCLF due to HBV reactivation in select lymphoma patients.

APACHE II score is superior to SOFA, CTP and MELD in predicting the short-term mortality in patients with acute-on-chronic liver failure (ACLF)

OBJECTIVE

The aim of the study was to assess the performance of various prognostic scores including the acute physiology and chronic health evaluation (APACHE II), sequential organ failure assessment (SOFA), Child-Turcotte-Pugh (CTP) and model for end-stage liver disease (MELD) scores in predicting short-term mortality in patients with acute-on-chronic liver failure (ACLF).

METHODS

Altogether 100 consecutive patients with ACLF were evaluated prospectively. The diagnosis of ACLF was based on the Asian-Pacific Association for the Study of the Liver criteria except for the inclusion of non-hepatic insults as acute events. Sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy for predicting short-term mortality was calculated for APACHE II, SOFA, CTP and MELD in all patients and Maddrey's discriminant function (DF) and Glasgow alcoholic hepatitis scores (GAHS) for patients with alcoholic hepatitis only.

RESULTS

Most patients had alcohol-related cirrhosis and alcoholic hepatitis as acute insults for ACLF. A total of 53 patients either died or left hospital in very sick status and were confirmed to have died the same day after leaving hospital. Overall, the area under the receiver operating characteristic curve of APACHE II was higher than those of MELD, SOFA and CTP scores for predicting short-term mortality. Even for patients with alcoholic hepatitis, APACHE II performed better than DF and GAHS.

CONCLUSIONS

Short-term mortality is high in patients with ACLF. APACHE II scoring system is superior to other prognostic scores in predicting its short-term mortality.

Hepatitis E and Acute-on-Chronic Liver Failure

Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis (AVH) globally. It causes large scale epidemics of AVH across the low- and middle income countries in Asia and Africa, and also causes sporadic cases of AVH in the same geographical region. AVH due to HEV is usually an acute, self-limiting illness, similar in clinical presentation to AVH caused by hepatitis A virus (HAV). When HEV causes AVH in patients of chronic liver disease it may worsen rapidly to a syndrome called acute-on-chronic liver failure (ACLF) leading to very high mortality. Acute deterioration of liver function in a patient with compensated chronic liver disease is the characteristic feature of ACLF. The typical disease course of patients with ACLF is the appearance of organ failure, which progresses to multi-organ failure and death. Many publications have reported HEV as one of the leading causes for ACLF from Asia and Africa, where HEV is endemic. The mortality rate of HEV-related ACLF (HEV-ACLF) ranges from 0% to 67% with a median being 34%. These patients require admission in the intensive care unit and they benefit from a team approach of clinicians with expertise in both hepatology and critical care. The goals of treatment are to prevent further deterioration in liver function, reverse precipitating factors, and support failing organs. Liver transplantation is required in selected patients to improve survival and quality of life. One preliminary report suggests that ribavirin may be an effective and safe drug for treatment of HEV-ACLF however this requires validation in large trials.

Extracorporeal detoxification for hepatic failure using molecular adsorbent recirculating system: depurative efficiency and clinical results in a long-term follow-up

Acute liver failure and acute-on-chronic liver failure still show a poor prognosis. The molecular adsorbent recirculating system (MARS) has been extensively used as the most promising detoxifying therapy for patients with these conditions. Sixty-four patients with life-threatening liver failure were selected, and 269 MARS treatments were carried out as a bridge for orthotopic liver transplantation (OLT) or for liver function recovery. All patients were grouped according to the aim of MARS therapy. Group A consisted of 47 patients treated for liver function recovery (median age 59 years, range 23-82). Group B consisted of 11 patients on the waiting list who underwent OLT (median age 47 years, range 32-62). Group C consisted of 6 patients on the waiting list who did not undergo OLT (median age 45.5 years, range 36-54, P = 0.001). MARS depurative efficiency in terms of liver toxins, cytokines, and growth factors was assessed together with the clinical outcome of the patients during a 1-year follow-up. Total bilirubin reduction rate per session (RRs) for each MARS session was 23% (range 17-29); direct bilirubin RRs was 28% (21-35), and indirect bilirubin RRs was 8% (3-21). Ammonia RRs was 34% (12-86). Conjugated cholic acid RRs was 58% (48-61); chenodeoxycholic acid RRs was 34% (18-48). No differences were found between groups. Hepatocyte growth factor (HGF) values on starting MARS were 4.1 ng/mL (1.9-7.9) versus 7.9 ng/mL (3.2-14.1) at MARS end (P < 0.01). Cox regression analysis to determine the risk factors predicting patient outcomes showed that age, male gender, and Sequential Organ Failure Assessment score (but not Model for End-stage Liver Disease score) were factors predicting death, whereas the number of MARS sessions and the ΔHGF proved protective factors. Kaplan-Meier survival analysis was also used; after 12 months, 21.3% of patients in Group A survived, while 90.9% were alive in Group B and 16.7% in Group C (log rank = 0.002). In conclusion, MARS was clinically well tolerated by all patients and significantly reduced hepatic toxins. Better survival rates were linked to an OLT program, but patients' clinical characteristics on starting MARS therapy were the main factors predicting survival. The role of HGF should be evaluated in larger clinical trials.

Gastrointestinal complications of obesity: non-alcoholic fatty liver disease (NAFLD) and its sequelae

Obesity is a major risk factor for malign and non-malign diseases of the gastrointestinal tract. Non-alcoholic fatty liver disease (NAFLD) is an outstanding example for the complex pathophysiology of the metabolic system and represents both source and consequence of the metabolic syndrome. NAFLD has a growing prevalence and will become the leading cause of advanced liver disease and cirrhosis. Obesity has a negative impact on NAFLD at all aspects and stages of the disease. The growing epidemic will strain health care resources and demands new concepts for prevention, screening and therapeutic approaches. A better understanding of the interplay of liver, gut and hormonal system is necessary for new insights in the underlying mechanisms of NAFLD and the metabolic syndrome including obesity. Identification of patients at risk for progressive liver disease will allow a better adaption of treatment strategies.

A guide to the management of tuberculosis in patients with chronic liver disease

Tuberculosis remains one of the 'Captains of the Men of Death' even today, particularly in the developing world. Its frequency is increased 14-fold in patients with chronic liver diseases (CLD) and liver cirrhosis, more so in those with decompensated disease, probably due to the cirrhosis-associated immune dysfunction syndrome, and case-fatality rates are high. The diagnosis of tuberculosis, particularly the interpretation of the Mantoux test, is also fraught with difficulties in CLD, especially after previous BCG vaccination. However, the greatest challenge in the patient with CLD or liver cirrhosis and tuberculosis is managing their therapy since the best first-line anti-tuberculosis drugs are hepatotoxic and baseline liver function is often deranged. Frequency of hepatotoxicity is increased in those with liver cirrhosis, chronic hepatitis B and chronic hepatitis C, possibly related to increased viral loads and may be decreased following antiviral therapy. If hepatotoxicity develops in those with liver cirrhosis, particularly decompensated cirrhosis, the risk of severe liver failure is markedly increased. Currently, there are no established guidelines for anti-tuberculosis therapy (ATT) in CLD and liver cirrhosis although the need for such guidelines is self-evident. It is proposed that ATT should include no more than 2 hepatotoxic drugs (RIF and INH) in patients with CLD or liver cirrhosis and stable liver function [Child-Turcotte-Pugh (CTP) ≤7], only a single hepatotoxic drug (RIF or INH) in those with advanced liver dysfunction (CTP 8-10) and no hepatotoxic drugs with very advanced liver dysfunction (CTP ≥11). A standard protocol should be followed for monitoring ATT-related hepatotoxicity and for stop rules and reintroduction rules in all these patients, on the lines proposed here. It is hoped that these proposals will introduce uniformity and result in streamlining the management of these difficult patients.

Hepatic stellate cells are involved in the pathogenesis of acute-on-chronic liver failure (ACLF)

ACLF is a condition with varied acute and chronic underlying etiologies and high mortality. Hepatic stellate cells (HSCs) are known to play an important role in hepatic fibrogenesis. Experimental data suggest that HSCs also display characteristics of hepatic stem/progenitor cells (HPCs). We investigated the number of activated HSC and their relationship to HPCs in ACLF in comparison to acute and chronic stages of other liver diseases. Immunohistochemical analysis of the number of activated HSCs and HPCs was performed in liver biopsies of 70 cases of ACLF and in the biopsies of patients with cirrhosis (45), acute hepatitis (25), chronic hepatitis (25), and normal live-related liver transplantation (LDLT) donor biopsies (15). The number of α-SMA-positive HSCs was assessed both quantitatively and semi-quantitatively. Keratin-19 (K19)-positive HPCs were estimated semi-quantitatively, and we looked for correlations between numbers of HSCs and HPCs. We found significantly more α-SMA activated HSCs/1,000 hepatocytes in ACLF biopsies (231 ± 91) than in biopsies of patients with acute hepatitis (147 ± 77), cirrhosis (73 ± 35), chronic hepatitis (66 ± 30), and normal LDLT donor biopsies (25 ± 10), respectively (p < 0.0001). A significant correlation between the presence of HPCs and ACLF versus other etiologies of liver disease was found (p < 0.001). There was a significant correlation between the numbers of HPCs and of activated HSCs (p < 0.001). ACLF is associated with more significant HSC activation than in acute hepatitis and other chronic liver diseases. There is a significant relationship between the presence of HSCs and that of HPCs, indicating a possible dynamic role of HSCs in liver regeneration and pathobiology of ACLF.

Hepatic encephalopathy: An approach to its multiple pathophysiological features

Hepatic encephalopathy (HE) is a neuropsychiatric complex syndrome, ranging from subtle behavioral abnormalities to deep coma and death. Hepatic encephalopathy emerges as the major complication of acute or chronic liver failure. Multiplicity of factors are involved in its pathophysiology, such as central and neuromuscular neurotransmission disorder, alterations in sleep patterns and cognition, changes in energy metabolism leading to cell injury, an oxidative/nitrosative state and a neuroinflammatory condition. Moreover, in acute HE, a condition of imminent threat of death is present due to a deleterious astrocyte swelling. In chronic HE, changes in calcium signaling, mitochondrial membrane potential and long term potential expression, N-methyl-D-aspartate-cGMP and peripheral benzodiazepine receptors alterations, and changes in the mRNA and protein expression and redistribution in the cerebral blood flow can be observed. The main molecule indicated as responsible for all these changes in HE is ammonia. There is no doubt that ammonia, a neurotoxic molecule, triggers or at least facilitates most of these changes. Ammonia plasma levels are increased two- to three-fold in patients with mild to moderate cirrhotic HE and up to ten-fold in patients with acute liver failure. Hepatic and inter-organ trafficking of ammonia and its metabolite, glutamine (GLN), lead to hyperammonemic conditions. Removal of hepatic ammonia is a differentiated work that includes the hepatocyte, through the urea cycle, converting ammonia into GLN via glutamine synthetase. Under pathological conditions, such as liver damage or liver blood by-pass, the ammonia plasma level starts to rise and the risk of HE developing is high. Knowledge of the pathophysiology of HE is rapidly expanding and identification of focally localized triggers has led the development of new possibilities for HE to be considered. This editorial will focus on issues where, to the best of our knowledge, more research is needed in order to clarify, at least partially, controversial topics.

A prospective randomized open-label crossover trial of regional citrate anticoagulation vs. anticoagulation free liver dialysis by the Molecular Adsorbents Recirculating System

Introduction

The Molecular Adsorbent Recycling System (MARS) is used to treat patients with liver failure. Observational data suggest that citrate anticoagulation during MARS is feasible. Comparative studies on the optimal anticoagulation regimen during MARS are lacking. The aim of the current study was to evaluate two heparin-free anticoagulation regimens.

Methods

We performed a prospective randomized open-label crossover study of regional citrate anticoagulation against no anticoagulation. Ten patients (age 55 ± 11 years) with liver failure undergoing MARS treatment were included. The primary endpoint was completion of MARS sessions. Secondary endpoints included treatment efficacy and safety. Longevity of MARS treatment was plotted as a Kaplan-Meier estimate. Fisher's exact test was used for contingency table analysis.

Results

Of a total of 27 6-hour sessions, four sessions had to be terminated prematurely, three due to occlusive clotting of the extracorporeal circuit and one due to uncontrollable bleeding from the vascular access site. All four events occurred in the group without anticoagulation. Between group comparison demonstrated citrate anticoagulation to significantly increase the likelihood of completed MARS treatment (Fisher's exact test, P 0.04). This translates into higher bilirubin reduction ratios when citrate was applied (reduction ratio 0.25 vs. 0.15, P 0.02). Systemic ionized calcium concentrations were significantly reduced during citrate anticoagulation (P < 0.001) but remained within a safe range. We observed no major adverse events.

Conclusions

Regional citrate anticoagulation in patients with liver failure is feasible. Citrate anticoagulation provides superior patency of the extracorporeal circuit. Avoidance of anticoagulation during MARS results in significant loss of treatment efficacy, due to treatment downtime. Additional studies are required to identify the optimal anticoagulation regimen for extracorporeal circulation in patients with liver failure.

Artificial liver support devices as treatment option for liver failure

Non-biological artificial liver support (ALS) devices aim to remove albumin-bound and water-soluble toxins arising as a result of liver failure. They do not directly improve the liver synthetic capacity. The currently most used devices combine haemodialysis with albumin dialysis (MARS) or plasma separation and filtration (Prometheus). These devices have been used as a treatment for different types of liver failure: acute liver failure, acute-on-chronic liver failure and primary non- or poor-function after liver transplantation. Overall these devices are found to be safe. The following beneficial effects have been documented: improvement of jaundice, amelioration of haemodynamic instability, reduction of portal hypertension, lowering of intracranial pressure and improvement of hepatic encephalopathy. However, recently multicentre controlled trials failed to show a beneficial effect on transplant-free survival. Therefore the use of these devices at present seems only justified as a bridge to liver transplantation.

IκB kinase-beta inhibitor attenuates hepatic fibrosis in mice

AIM: To investigate the anti-fibrosis effect of IκB kinase-beta inhibitor (IKK2 inhibitor IMD0354) in liver fibrosis.

METHODS: Twenty male C57BL6 mice were divided into four groups. Five high-fat fed mice were injected with lipopolysaccharide (LPS, 10 mg/kg) intraperitoneally and five high-fat fed mice were without LPS injection to build models of liver injury, and the intervention group (five mice) was injected intraperitoneally with IKK2 inhibitor (IMD 30 mg/kg for 14 d), while the remaining five mice received a normal diet as controls. Hepatic function, pathological evaluation and liver interleukin-6 (IL-6) expression were examined. Western blotting and real-time polymerase chain reaction were used to detect the expressions of nuclear factor-κB (NF-κB), alpha-smooth muscle actin (α-SMA), tumor growth factor-beta1 (TGF-β1), tumor necrosis factor-alpha (TNF-α), typeIand type III collagen proteins and mRNA.

RESULTS: A mouse model of liver injury was successfully established, and IMD decreased nuclear translocation of NF-κB p65 in liver cells. In the IMD-treated group, the levels of alanine aminotransferase (103 ± 9.77 μ/L vs 62.4 ± 7.90 μ/L, P < 0.05) and aminotransferase (295.8 ± 38.56 μ/L vs 212 ± 25.10 μ/L, P < 0.05) were significantly decreased when compared with the model groups. The histological changes were significantly ameliorated. After treatment, the expressions of IL-6 (681 ± 45.96 vs 77 ± 7.79, P < 0.05), TGF-β1 (Western blotting 5.65% ± 0.017% vs 2.73% ± 0.005%, P < 0.05), TNF-α (11.58% ± 0.0063% vs 8.86% ± 0.0050%, P < 0.05), typeIcollagen (4.49% ± 0.014% vs 1.90% ± 0.0006%, P < 0.05) and type III collagen (3.46% ± 0.008% vs 2.29% ± 0.0035%, P < 0.05) as well as α-SMA (6.19 ± 0.0036 μ/L vs 2.16 ± 0.0023 μ/L, P < 0.05) protein and mRNA were downregulated in the IMD group compared to the fibrosis control groups (P < 0.05).

CONCLUSION: IKK2 inhibitor IMD markedly improved non-alcoholic fatty liver disease in mice by lowering NF-κB activation, which could become a remedial target for liver fibrosis.