Pathogenesis Of Acute-on-chronic Liver Failure Research Articles

Distinct immunometabolic signatures in circulating immune cells define disease outcome in acute-on-chronic liver failure.

Acute-on-chronic liver failure (ACLF) is a complication of cirrhosis characterized by multiple organ failure and high short-term mortality. The pathophysiology of ACLF involves elevated systemic inflammation leading to organ failure, along with immune dysfunction that heightens susceptibility to bacterial infections. However, it is unclear how these aspects are associated with recovery and non-recovery in ACLF. Here we mapped the single-cell transcriptome of circulating immune cells from ACLF-, acute decompensated (AD) cirrhosis patients and healthy individuals. We further interrogate how these findings as well as immunometabolic- and functional profiles associate with ACLF recovery (ACLF-R) or non-recovery (ACLF-NR). Our analysis unveiled two distinct states of classical monocytes (cMon). Hereto, ACLF-R cMons were characterized by transcripts associated with immune- and stress tolerance, including anti-inflammatory genes such as RETN and LGALS1. Additional metabolomic- and functional validation experiments implicated an elevated oxidative phosphorylation metabolic program as well as an impaired ACLF-R cMon functionality. Interestingly, we observed a common stress-induced tolerant state, oxidative phosphorylation program and blunted activation among lymphoid populations in ACLF-R patients. Conversely, ACLF-NR cMon featured elevated expression of inflammatory- and stress response genes such as VIM, LGALS2, and TREM1 along with blunted metabolic activity and increased functionality. This study identifies distinct immuno-metabolic cellular states that contribute to disease outcome in ACLF patients. Our findings provide valuable insights into the pathogenesis of ACLF, shedding light on factors driving either recovery or non-recovery phenotypes which may be harnessed as potential therapeutic targets in the future.

The Role of Hypoxia-Inducible Factor 1 Alpha in Acute-on-Chronic Liver Failure.

Acute-on-chronic liver failure (ACLF) is associated with increased mortality. Specific therapy options are limited. Hypoxia-inducible factor 1 alpha (HIF-1α) has been linked to the pathogenesis of chronic liver disease (CLD), but the role of HIF-1α in ACLF is poorly understood. In the current study, different etiologies of CLD and precipitating events triggering ACLF were used in four rodent models. HIF-1α expression and the intracellular pathway of HIF-1α induction were investigated using real-time quantitative PCR. The results were verified by Western blotting and immunohistochemistry for extrahepatic HIF-1α expression using transcriptome analysis. Exploratory immunohistochemical staining was performed to assess HIF-1α in human liver tissue. Intrahepatic HIF-1α expression was significantly increased in all animals with ACLF, regardless of the underlying etiology of CLD or the precipitating event. The induction of HIF-1α was accompanied by the increased mRNA expression of NFkB1 and STAT3 and resulted in a marked elevation of mRNA levels of its downstream genes. Extrahepatic HIF-1α expression was not elevated. In human liver tissue samples, HIF-1α expression was elevated in CLD and ACLF. Increased intrahepatic HIF-1α expression seems to play an important role in the pathogenesis of ACLF, and future studies are pending to investigate the role of therapeutic HIF inhibitors in ACLF.

Knockdown of CXCL1 improves ACLF by reducing neutrophil recruitment to attenuate ROS production and hepatocyte apoptosis.

Acute-on-chronic liver failure (ACLF) is an acute decompensated syndrome based on chronic liver disease, while neutrophil recruitment is the most critical early step. C-X-C motif chemokine ligand 1 (CXCL1), a cytokine that recruits neutrophils, was significantly upregulated in both ACLF mice and patients with ACLF. This present study aims to explore the role of CXCL1 in the pathogenesis of ACLF. We established an ACLF mouse model induced by carbon tetrachloride, lipopolysaccharide, and D-galactosamine, and used adeno-associated virus to achieve overexpression and knockdown of Cxcl1. We employed mass cytometry, flow cytometry, multiplex cytokine and chemokine analysis, Western blot, and reactive oxygen species (ROS) detection in mice blood and liver. ACLF patients (n = 10) and healthy controls (n = 5) were included, and their liver samples were stained using multiplex immunohistochemistry techniques. CXCL1 was significantly elevated in both ACLF mice and patients. CXCL1 recruits neutrophils by binding to the C-X-C motif chemokine receptor 2 on the surface of neutrophils, affects ACLF prognosis by generating ROS and mitochondrial depolarization and modulating caspase3-related apoptotic pathways. We found that the knockdown of CXCL1 attenuated the infiltration of neutrophils in the mouse liver, reduced the expression of inflammatory cytokines, and also significantly downregulated ROS production and caspase3-related hepatocyte apoptosis, thereby ameliorating the liver injury of ACLF. CXCL1 is a core player in the mobilization of neutrophils in ACLF, and the knockdown of Cxcl1 improves neutrophil infiltration, reduces ROS levels, and reduces hepatocyte apoptosis, thereby attenuating inflammation and liver injury in ACLF. Our results revealed a previously unknown link between CXCL1-induced neutrophil recruitment and ACLF, providing evidencing for potential therapies targeting ACLF.

Pathogenetic mechanisms and therapeutic approaches of acute-to-chronic liver failure.

Liver cirrhosis is the end stage of all chronic liver diseases and contributes significantly to overall mortality of 2% globally. The age-standardized mortality from liver cirrhosis in Europe is between 10 and 20% and can be explained by not only the development of liver cancer but also the acute deterioration in the patient's overall condition. The development of complications including accumulation of fluid in the abdomen (ascites), bleeding in the gastrointestinal tract (variceal bleeding), bacterial infections, or a decrease in brain function (hepatic encephalopathy) define an acute decompensation that requires therapy and often leads to acute-on-chronic liver failure (ACLF) by different precipitating events. However, due to its complexity and organ-spanning nature, the pathogenesis of ACLF is poorly understood, and the common underlying mechanisms leading to the development of organ dysfunction or failure in ACLF are still elusive. Apart from general intensive care interventions, there are no specific therapy options for ACLF. Liver transplantation is often not possible in these patients due to contraindications and a lack of prioritization. In this review, we describe the framework of the ACLF-I project consortium funded by the Hessian Ministry of Higher Education, Research and the Arts (HMWK) based on existing findings and will provide answers to these open questions.

EASIX Is an Accurate and Easily Available Prognostic Score in Critically Ill Patients with Advanced Liver Disease

Acute-on-chronic liver failure (ACLF) is associated with high mortality. Objective prognostic scores are important for treatment decisions. EASIX (Endothelial Activation and Stress Index) is a simple biomarker consisting of LDH, platelets, and creatinine, reflecting endothelial dysfunction after allogeneic stem cell transplantation. Considering endothelial dysfunction in the pathogenesis of ACLF, this study aimed to test the discriminative ability of EASIX in advanced liver disease. We retrospectively analysed the prognostic potential of EASIX to predict 28-day and 3-month mortality in a total of 188 liver cirrhotic patients requiring treatment at the intensive care unit. We evaluated the ability of EASIX to rule out early infections and predict the need for hemodialysis. EASIX performed moderately better than established scores in predicting 28-day mortality (AUC = 0.771) and was nearly equivalent (AUC = 0.791) to SOFA and APACHE-II in the prediction of 3-month mortality. Importantly, EASIX showed better diagnostic potential in ruling out clinically apparent infections than common proinflammatory markers (AUC = 0.861, p < 0.001) and showed suitable accuracy in predicting the need for hemodialysis (AUC = 0.833). EASIX is an accurate, objective and easily assessable biomarker for predicting mortality and complications in patients with advanced liver disease.

Systemic inflammatory regulators and risk of acute-on-chronic liver failure: A bidirectional mendelian-randomization study.

Inflammation plays a role in the pathogenesis of acute-on-chronic liver failure (ACLF), however, whether there is a causal relationship between inflammation and ACLF remains unclear. A two-sample Mendelian randomization (MR) approach was used to investigate the causal relationship between systemic inflammatory regulators and ACLF. The study analyzed 41 cytokines and growth factors from 8,293 individuals extracted from a genome-wide association study (GWAS) meta-analysis database involving 253 ACLF cases and 456,095 controls. Our results showed that lower stem cell factor (SCF) levels, lower basic fibroblast growth factor (bFGF) levels and higher Interleukin-13 (IL-13) levels were associated with an increased risk of ACLF (OR = 0.486, 95% CI = 0.264-0.892, p = 0.020; OR = 0.323, 95% CI = 0.107-0.972, p = 0.044; OR = 1.492, 95% CI = 1.111-2.004, p = 0.008, respectively). In addition, genetically predicted ACLF did not affect the expression of systemic inflammatory regulators. Our results indicate that cytokines play a crucial role in the pathogenesis of ACLF. Further studies are needed to determine whether these biomarkers can be used to prevent and treat ACLF.

Acute-on-chronic liver failure: definition, diagnosis, and pathogenesis

Acute-on-chronic liver failure (ACLF) is a form of complex syndrome with acute deterioration of liver function that occurs on the basis of chronic liver disease, and is accompanied by hepatic and extrahepatic organ failure with high mortality rate. The short-term mortality rate of comprehensive internal medicine treatment is as high as 50%-90%. This paper summarizes the current common definitions and diagnostic criteria, early-warning prediction models, and pathogenesis of ACLF.

Presence of Serum Antinuclear Antibodies Does Not Impact Outcomes in HBV-Related Acute-on-Chronic Liver Failure.

Background The aim of this study was to provide new insights into the prevalence of positive antinuclear antibody (ANA) in patients with HBV-related acute-on-chronic liver failure (ACLF) and its impact on clinical outcomes. Methods A total of 116 patients with HBV-related ACLF treated at three clinical centers were retrospectively recruited. Serum concentrations of ANA were detected using the enzyme-linked immunosorbent assay kit. Multiple nuclear dots, rim-like, and centromere patterns of ANA were detected using indirect immunofluorescence assay on HEp-2 cells. Results Among the 116 patients with HBV-related ACLF, 17 (14.66%) were ANA positive. Most patients in both ANA positive and negative groups were males (88.2% and 83.8%). Patients with negative ANA had a higher international normalized ratio, model for end-stage liver disease (MELD), and MELD-sodium scores than those with positive ANA (all P < 0.05). Multiple nuclear dot pattern was detected in half of the patients (8/17, 47.06%), rim-like/membranous pattern was found in six patients, and centromere pattern was detected in the last three patients. For patients with ANA (+), IgM was lower, and it was positively correlated with IgG. For patients with ANA (-), C3 was positively correlated with C4, and both C3 and C4 were negatively correlated with INR and MELD (all P < 0.05). In addition, TBIL, INR, WBC, and PLT, but not ANA, resulted as independent risk factors associated with 90-day mortality. Conclusion Positive ANA is frequent in HBV-related ACLF, and it does not seem to be associated with poor outcomes, but the pathogenesis of ACLF may be different between ANA (+) and ANA (−) groups.

Acute-on-chronic liver failure: update on pathogenesis, therapeutic targets, predictive models, and liver transplantation.

Acute-on-chronic liver failure (ACLF) is a clinical syndrome in patients with chronic liver disease that is associated with multiple organ failures and a high short-term mortality. Systemic inflammation is suggested to play a key role in its pathogenesis, although the precise causative mechanism is unknown. The purpose of this review is to present and discuss new findings related to: mechanisms underlying ACLF, therapeutic targets, risk prediction models for developing ACLF, and liver transplantation for ACLF. Recent studies of ACLF pathophysiology classified the immunosuppressive phenotype in monocytes. Investigation of therapeutic strategies identified inhibition of toll-like receptor-4 (TLR-4) and glutamine synthetase (GLUL) as potential targets. Recent studies identified novel risk prediction models for developing ACLF and enhanced our understanding of liver transplantation for ACLF to guide clinicians in determining that patients will benefit from transplantation. Improved knowledge on the pathogenesis of ACLF and identification of TLR-4 and GLUL may lead to clinical trials to study the efficacy of these novel therapeutic targets for patients with ACLF. Liver transplantation is the only current treatment for ACLF. Given the limited availability of donor organs, recent studies have identified ACLF patients who may merit the highest waitlist priority.

Prognostic value of neutrophil-to-lymphocyte ratio in cirrhotic patients with acute-on-chronic liver failure

Patients with cirrhosis hospitalized in the intensive care unit (ICU) have a high risk for acute-on-chronic liver failure (ACLF) and short-term mortality. A major factor in the pathogenesis of ACLF is systemic inflammation, the assessment of which includes the use of surrogate markers, such as neutrophil-to-lymphocyte ratio (NLR). This study aimed to assess the accuracy of NLR in predicting the outcome of patients with cirrhosis and ACLF hospitalized in the ICU. This was a retrospective observational study on patients with cirrhosis with acute decompensation hospitalized in the ICU of a Romanian tertiary care center. ACLF was defined according to the CANONIC criteria, and NLR was calculated by dividing the absolute neutrophil count by the absolute lymphocyte count. A total of 70 patients were included, of whom 70% were men with a mean age of 62±6.2 years. ACLF was diagnosed in 58 (82.9%) patients who presented with higher in-hospital mortality rates than patients without ACLF (84.5% vs. 33.3%, p=0.001). The mean NLR value was 11.7±9.5, higher in non-survivors than in survivors (12.6±9.8 vs. 8.6±7.8, p=0.170). NLR had a poor accuracy in predicting the outcome in patients without ACLF (area under the curve [AUC]=0.611) but a better accuracy in patients with ACLF (AUC=0.776). Patients with cirrhosis and a high NLR had higher levels of bilirubin; higher Child-Turcotte-Pugh score; and higher incidence of ascites, coagulation, and circulatory failure, presenting a poor outcome. Receiver operating characteristic analysis showed a good accuracy for predicting mortality for the Child-Turcotte-Pugh score (AUC= 0.864) and NLR (AUC=0.732). NLR is a promising and cost-effective method for the prediction of a poor outcome in critically ill patients with cirrhosis hospitalized in the ICU and shows greater accuracy in those with ACLF.

Long Non-coding RNA NEAT1 Alleviates Acute-on-Chronic Liver Failure Through Blocking TRAF6 Mediated Inflammatory Response

BackgroundLong non-coding RNAs (lncRNAs) have recently been tightly linked to plenty of human diseases. However, knowledge of acute-on-chronic liver failure (ACLF) related lncRNAs remains insufficient. In this work, we studied the role of the lncRNA nuclear enriched abundant transcript 1 (NEAT1) in the pathogenesis of ACLF.MethodsACLF model was established by challenging D-galactosamine (D-GalN)/ lipopolysaccharide (LPS) i.p. in rats with cirrhosis. The serum levels of IL-1, IL-6, and HMGB1 were determined using ELISA. Quantitative real time-PCR and western blot were performed to evaluate RNA and protein levels of inflammatory response. RNA immunoprecipitation assay was performed to confirm protein that interacts with NEAT1.FindingsOver-expression of NEAT1 could interact with TRAF6 and decrease its ubiquitination level, and significantly reduced the expression levels of IL-6, IL-22. Importantly, in ACLF rat model, NEAT1 over-expression reduced several cytokines expression and alleviated the pathological status in contrast to the control group. Additionally, NEAT1 was increased and positively correlated with IL-22 and IL-6 levels in PBMCs from the ACLF patients.InterpretationNEAT1 can suppress inflammatory response through blockade of TRAF6 ubiquitination in ACLF rat model, suggesting that lncRNA NEAT1 might play protective roles in the pathogenesis of ACLF and provide promising novel target for pharmacological intervention.

Orchestration of Tryptophan-Kynurenine Pathway, Acute Decompensation, and Acute-on-Chronic Liver Failure in Cirrhosis.

Systemic inflammation (SI) is involved in the pathogenesis of acute decompensation (AD) and acute-on-chronic liver failure (ACLF) in cirrhosis. In other diseases, SI activates tryptophan (Trp) degradation through the kynurenine pathway (KP), giving rise to metabolites that contribute to multiorgan/system damage and immunosuppression. In the current study, we aimed to characterize the KP in patients with cirrhosis, in whom this pathway is poorly known. The serum levels of Trp, key KP metabolites (kynurenine and kynurenic and quinolinic acids), and cytokines (SI markers) were measured at enrollment in 40 healthy subjects, 39 patients with compensated cirrhosis, 342 with AD (no ACLF) and 180 with ACLF, and repeated in 258 patients during the 28-day follow-up. Urine KP metabolites were measured in 50 patients with ACLF. Serum KP activity was normal in compensated cirrhosis, increased in AD and further increased in ACLF, in parallel with SI; it was remarkably higher in ACLF with kidney failure than in ACLF without kidney failure in the absence of differences in urine KP activity and fractional excretion of KP metabolites. The short-term course of AD and ACLF (worsening, improvement, stable) correlated closely with follow-up changes in serum KP activity. Among patients with AD at enrollment, those with the highest baseline KP activity developed ACLF during follow-up. Among patients who had ACLF at enrollment, those with immune suppression and the highest KP activity, both at baseline, developed nosocomial infections during follow-up. Finally, higher baseline KP activity independently predicted mortality in patients with AD and ACLF. Conclusion: Features of KP activation appear in patients with AD, culminate in patients with ACLF, and may be involved in the pathogenesis of ACLF, clinical course, and mortality.

Acute-on-Chronic Liver Failure: Getting Ready for Prime Time?

ACLF is a clinically relevant syndrome that is epidemic worldwide and requires a dedicated multinational approach focused on prognostication and management; investigations are underway worldwide to prepare ACLF for prime time. (Hepatology 2018; 00:000-000).

Increased intestinal permeability in patients with acute-on chronic liver failure (ACLF): an update on the pathogenesis of ACLF

Increased intestinal permeability in patients with acute-on chronic liver failure (ACLF): an update on the pathogenesis of ACLF

The Pathogenesis of ACLF: The Inflammatory Response and Immune Function.

Although systemic inflammation is a hallmark of acute-on-chronic liver failure (ACLF), its role in the development of this syndrome is poorly understood. Here the author first summarizes the general principles of the inflammatory response. Inflammation can be triggered by exogenous or endogenous inducers. Important exogenous inducers include bacterial products such as pathogen-associated molecular patterns (PAMPs) and virulence factors. Pathogen-associated molecular patterns elicit inflammation through structural feature recognition (using innate pattern-recognition receptors [PRRs]), whereas virulence factors generally trigger inflammation via functional feature recognition. Endogenous inducers are called danger-associated molecular patterns (DAMPs) and include molecules released by necrotic cells and products of extracellular matrix breakdown. Danger-associated molecular patterns use different PRRs. The purpose of the inflammatory response may differ according to the type of stimulus: The aim of infection-induced inflammation is to decrease pathogen burden, whereas the DAMP-induced inflammation aims to promote tissue repair. An excessive inflammatory response can induce collateral tissue damage (a process called immunopathology). However immunopathology may not be the only mechanism of tissue damage; for example, organ failure can develop because of failed disease tolerance. In this review, the author also discusses how general principles of the inflammatory response can help us to understand the development of ACLF in different contexts: bacterial infection, severe alcoholic hepatitis, and cases in which there is no identifiable trigger.

ITRAQ-based proteomic analysis of hepatic tissues from patients with hepatitis B virus-induced acute-on-chronic liver failure.

The pathogenesis of hepatitis B virus (HBV)-induced acute-on-chronic liver failure (ACLF), a serious and prevalent medical condition, is not clear, particularly with regard to which proteins are expressed in the course of the disease. The aim of the present study was to identify the differences in hepatic tissue protein expression between normal human subjects and patients with ACLF using isobaric tags for relative and absolute quantification (iTRAQ)-based proteomic analysis and to verify the results using western blot analysis. The iTRAQ method was used to analyze the protein contents of hepatic tissue samples from 3 patients with HBV-induced ACLF and 3 normal healthy subjects. The results were verified by subjecting the hepatic tissues from 2 patients with HBV-induced ACLF and 4 healthy subjects to western blot analysis. In total, 57 proteins with ≥1.5-fold differences between patients with HBV-induced ACLF and healthy subjects were identified using iTRAQ. Among these 57 proteins, 4 with the most marked differences in their expression and the most significant association with liver disease were selected to be verified through western blot analysis: Keratin, type-I cytoskeletal 19; α-1-acid glycoprotein 1 (α1-AGP); carbonic anhydrase-1; and serpin peptidase inhibitor and clade A (α-1 anti proteinase, antitrypsin) member 1 (SERPINA1). The results of the western blot analyses were nearly identical to the iTRAQ results. Identifying the differences in liver protein expression in patients with HBV-induced ACLF may provide a basis for studies on the pathogenesis of ACLF. Future studies should focus particularly on α1-AGP, carbonic anhydrase 1 and SERPINA1.

The dysregulation of endoplasmic reticulum stress response in acute-on-chronic liver failure patients caused by acute exacerbation of chronic hepatitis B.

Although endoplasmic reticulum (ER) stress is critical in various liver diseases, its role in acute-on-chronic liver failure (AoCLF) caused by acute exacerbation of chronic hepatitis B (CHB) is still elusive. This study aimed to analyse ER stress responses in the progression of HBV-related AoCLF. Normal liver tissues (n = 10), liver tissues of CHB (n = 12) and HBV-related patients with AoCLF (n = 19) were used. Electron microscopy of the ultrastructure of the ER was carried out on liver specimens. The gene and protein expression levels of ER stress-related genes were measured. We further analysed the correlation between the expression levels of ER stress-related molecules and liver injury. Electron microscopy identified typical features of the ER microstructure in AoCLF subjects. Among the three pathways of unfolded protein responses, the PKR-like ER kinase and inositol-requiring enzyme 1 signalling pathway were activated in CHB subjects and inactivated in AoCLF subjects, while the activating transcription factor 6 signalling pathway was sustained in the activated form during the progression of AoCLF; the expression of glucose-regulated protein (Grp)78 and Grp94 was gradually decreased in AoCLF subjects compared to healthy individuals and CHB subjects, showing a negative correlation with serum ALT, AST and TBIL; moreover, the ER stress-related apoptosis molecules were activated in the progression of acute exacerbation of CHB. The dysregulated ER stress response may play a complicated role in the pathogenesis of AoCLF, and a severe ER stress response may predict the occurrence of AoCLF caused by acute exacerbation of CHB.

Analysis of a urinary biomarker panel for clinical outcomes assessment in cirrhosis.

BackgroundBiomarkers are potentially useful in assessment of outcomes in patients with cirrhosis, but information is very limited. Given the large number of biomarkers, adequate choice of which biomarker(s) to investigate first is important.AimAnalysis of potential usefulness of a panel of urinary biomarkers in outcome assessment in cirrhosis.Patients and MethodsFifty-five patients with acute decompensation of cirrhosis were studied: 39 had Acute Kidney Injury (AKI) (Prerenal 12, type-1 HRS (hepatorenal syndrome) 15 and Acute Tubular Necrosis (ATN) 12) and 16 acute decompensation without AKI. Thirty-four patients had Acute-on-chronic liver failure (ACLF). A panel of 12 urinary biomarkers was assessed, using a multiplex assay, for their relationship with ATN, ACLF and mortality.ResultsBiomarker with best accuracy for ATN diagnosis was NGAL (neutrophil-gelatinase associated lipocalin): 36 [26-125], 104 [58-208] and 1807 [494-3,716] μg/g creatinine in Prerenal-AKI, type-1 HRS and ATN, respectively; p<0.0001 (AUROC 0.957). Other attractive biomarkers for ATN diagnosis were IL-18, albumin, trefoil-factor-3 (TFF-3) and glutathione-S-transferase-π (GST-π) Biomarkers with less accuracy for ATN AUCROC<0.8 were β2-microglobulin, calbindin, cystatin-C, clusterin and KIM-1 (kidney injury molecule-1). For ACLF, the biomarker with the best accuracy was NGAL (ACLF vs. No-ACLF: 165 [67-676] and 32 [19-40] μg/g creatinine; respectively; p<0.0001; AUROC 0.878). Interestingly, other biomarkers with high accuracy for ACLF were osteopontin, albumin, and TFF-3. Biomarkers with best accuracy for prognosis were those associated with ACLF.ConclusionsA number of biomarkers appear promising for differential diagnosis between ATN and other types of AKI. The most interesting biomarkers for ACLF and prognosis are NGAL, osteopontin, albumin, and TFF-3. These results support the role of major inflammatory reaction in the pathogenesis of ACLF.