What's new in acute liver failure?

The Mechanisms of Systemic Inflammatory and Immunosuppressive Acute-on-Chronic Liver Failure and Application Prospect of Single-Cell Sequencing

Acute-on-chronic liver failure (ACLF) is a complex clinical syndrome, and patients often have high short-term mortality. It occurs with intense systemic inflammation, often accompanied by a proinflammatory event (such as infection or alcoholic hepatitis), and is closely related to single or multiple organ failure. Liver inflammation begins when innate immune cells (such as Kupffer cells (KCs)) are activated by binding of pathogen-associated molecular patterns (PAMPs) from pathogenic microorganisms or damage-associated molecular patterns (DAMPs) of host origin to their pattern recognition receptors (PRRs). Activated KCs can secrete inflammatory factors as well as chemokines and recruit bone marrow-derived cells such as neutrophils and monocytes to the liver to enhance the inflammatory process. Bacterial translocation may contribute to ACLF when there are no obvious precipitating events. Immunometabolism plays an important role in the process (including mitochondrial dysfunction, amino acid metabolism, and lipid metabolism). The late stage of ACLF is mainly characterized by immunosuppression. In this process, the dysfunction of monocyte and macrophage is reflected in the downregulation of HLA-DR and upregulation of MER tyrosine kinase (MERTK), which weakens the antigen presentation function and reduces the secretion of inflammatory cytokines. We also describe the specific function of bacterial translocation and the gut-liver axis in the process of ACLF. Finally, we also describe the transcriptomics in HBV-ACLF and the recent progress of single-cell RNA sequencing as well as its potential application in the study of ACLF in the future, in order to gain a deeper understanding of ACLF in terms of single-cell gene expression.

Infectious complications and timing for liver transplantation in autoimmune acute liver failure in Japan: a subanalysis based on nationwide surveys between 2010 and 2015

BACKGROUND

The prognosis of autoimmune acute liver failure (ALF) without liver transplantation (LT) is poor worldwide. We subanalyzed infectious complications of autoimmune ALF using data of nationwide surveys between 2010 and 2015 retrospectively and tried to determine when to evaluate the efficacy of corticosteroid (CS) treatment or abandon it for LT based on objective data.

METHODS

One hundred and forty-four patients with autoimmune ALF, comprising 79 ALF with coma ≤ I, 52 ALF with coma ≥ II and 13 late onset hepatic failure (LOHF), were analyzed.

RESULTS

CS was administered to 140 (97%) patients. Thirty-seven (26%) patients had infectious complications. Patients with infection revealed more advanced disease type (p < 0.001) and poorer spontaneous survival (p < 0.001) than those without infection. Median (interquartile range) duration between diagnosis of ALF and onset of infection was 18.5 (11-36) days, and that between introduction of CS and onset of infection was 17 (10.5-36) days. Seventy-nine (55%) recovered without LT, 14 (10%) received LT and 51 (35%) died without LT. Dead or transplanted patients were older (p = 0.0057), and revealed more advanced liver failure (p < 0.001) and more occurrence of infection (p < 0.001).

CONCLUSIONS

A critical point for evaluating the efficacy of CS treatment and switching to LT is at most 2-week after diagnosis of ALF and introduction of CS. More important, we should accelerate the point and prepare for LT in cases of ALF with coma ≥ II and LOHF, and we should have performed LT by then at the latest in case of failure to improve.

Perspective of placenta derived mesenchymal stem cells in acute liver failure

Acute Liver failure (ALF) is a life-threatening disease and is determined by coagulopathy (with INR ≥ 1.5) and hepatic encephalopathy as a result of severe liver injury in patients without preexisting liver disease. Since there are problems with liver transplantation including lack of donors, use of immunosuppressive drugs, and high costs of this process, new therapeutic approaches alongside current treatments are needed. The placenta is a tissue that is normally discarded after childbirth. On the other hand, human placenta is a rich source of mesenchymal stem cells (MSCs), which is easily available, without moral problems, and its derived cells are less affected by age and environmental factors. Therefore, placenta-derived mesenchymal stem cells (PD-MSCs) can be considered as an allogeneic source for liver disease. Considering the studies on MSCs and their effects on various diseases, it can be stated that MSCs are among the most important agents to be used for novel future therapies of liver diseases. In this paper, we will investigate the effects of mesenchymal stem cells through migration and immigration to the site of injury, cell-to-cell contact, immunomodulatory effects, and secretory factors in ALF.

Acetaminophen Oxidation and Inflammatory Markers - A Review of Hepatic Molecular Mechanisms and Preclinical Studies

Acetaminophen is a widely used analgesic for pain management, especially useful in chronic diseases, such as rheumatoid arthritis. However, easy access to this medicine has increased the occurrence of episodes of poisoning. Patients often develop severe liver damage, which may quickly lead to death. Consequently, numerous studies have been conducted to identify new biomarkers that allow the prediction of the degree of acetaminophen intoxication and thus intervene in a timely manner to save patients' lives. This review highlights the main mechanisms of the induction and progression of liver damage arising from acetaminophen poisoning. In addition, we have discussed the possibility of using new clinical biomarkers for detecting acetaminophen poisoning.

Micro- and nanoparticles-based immunoregulation of macrophages for tissue repair and regeneration

The importance of inflammatory tissue microenvironment on the repair and regeneration of tissues and organs has been well recognized. In particular, the phenotypes of macrophages can significantly influence on the processes of tissue repair and remodeling. Among the many types of biomaterials, the particles in the range from nanometers to submicron meters have been extensively studied and applied in tissue engineering and regenerative medicine. They can actively interact with cells in different levels, and show the ability to regulate the polarization of macrophages. In this review, the influence of physicochemical properties such as size, surface charge, chemical components and surface modification of micro-nanoparticles on the immune behavior of macrophages, including endocytosis and phenotype switch, shall be introduced. The important roles of nanoparticles-based immunoregulation of macrophages on the chronic skin wounds regeneration, myocardial repair, liver repair and bone regeneration are discussed.

The platelet receptor CLEC-2 blocks neutrophil mediated hepatic recovery in acetaminophen induced acute liver failure

Acetaminophen (APAP) is the main cause of acute liver failure in the West. Specific efficacious therapies for acute liver failure (ALF) are limited and time-dependent. The mechanisms that drive irreversible acute liver failure remain poorly characterized. Here we report that the recently discovered platelet receptor CLEC-2 (C-type lectin-like receptor) perpetuates and worsens liver damage after toxic liver injury. Our data demonstrate that blocking platelet CLEC-2 signalling enhances liver recovery from acute toxic liver injuries (APAP and carbon tetrachloride) by increasing tumour necrosis factor-α (TNF-α) production which then enhances reparative hepatic neutrophil recruitment. We provide data from humans and mice demonstrating that platelet CLEC-2 influences the hepatic sterile inflammatory response and that this can be manipulated for therapeutic benefit in acute liver injury. Since CLEC-2 mediated platelet activation is independent of major haemostatic pathways, blocking this pathway represents a coagulopathy-sparing, specific and novel therapy in acute liver failure.

The Role of Monocytes and Macrophages in Acute and Acute-on-Chronic Liver Failure

Acute and acute-on-chronic liver failure (ALF and ACLF), though distinct clinical entities, are considered syndromes of innate immune dysfunction. Patients with ALF and ACLF display evidence of a pro-inflammatory state with local liver inflammation, features of systemic inflammatory response syndrome (SIRS) and vascular endothelial dysfunction that drive progression to multi-organ failure. In an apparent paradox, these patients are concurrently immunosuppressed, exhibiting acquired immune defects that render them highly susceptible to infections. This paradigm of tissue injury succeeded by immunosuppression is seen in other inflammatory conditions such as sepsis, which share poor outcomes and infective complications that account for high morbidity and mortality. Monocyte and macrophage dysfunction are central to disease progression of ALF and ACLF. Activation of liver-resident macrophages (Kupffer cells) by pathogen and damage associated molecular patterns leads to the recruitment of innate effector cells to the injured liver. Early monocyte infiltration may contribute to local tissue destruction during the propagation phase and results in secretion of pro-inflammatory cytokines that drive SIRS. In the hepatic microenvironment, recruited monocytes mature into macrophages following local reprogramming so as to promote resolution responses in a drive to maintain tissue integrity. Intra-hepatic events may affect circulating monocytes through spill over of soluble mediators and exposure to apoptotic cell debris during passage through the liver. Hence, peripheral monocytes show numerous acquired defects in acute liver failure syndromes that impair their anti-microbial programmes and contribute to enhanced susceptibility to sepsis. This review will highlight the cellular and molecular mechanisms by which monocytes and macrophages contribute to the pathophysiology of ALF and ACLF, considering both hepatic inflammation and systemic immunosuppression. We identify areas for further research and potential targets for immune-based therapies to treat these devastating conditions.

Early Combination Therapy with Corticosteroid and Nucleoside Analogue Induces Rapid Resolution of Inflammation in Acute Liver Failure due to Transient Hepatitis B Virus Infection

Objective Patients with acute hepatitis B sometimes develop acute liver failure (ALF), which has a poor prognosis. The efficacy of nucleoside analogue (NA) monotherapy for ALF due to transient hepatitis B virus infection (HBV-ALF) remains controversial. Further investigations are necessary in nations with a shortage of donor livers for liver transplantation. In the present study, we aimed to clarify the efficacy of combination therapy with corticosteroid (CS) and NA in the treatment HBV-ALF. Patients We examined the clinical and biochemical features of 19 patients with HBV-ALF who were treated in the early stage of the disease between 2000 and 2015. Results Fourteen patients received CS and NA (CS + NA group) and 5 received NA monotherapy (NA group). Eleven patients (58%) survived and 8 (42%) died. The survival rates in the CS + NA and NA groups were 64% and 40%, respectively (p=0.60). The mean alanine aminotransferase (ALT) levels declined significantly at week 2 in both groups. The mean PT activities improved significantly at weeks 1 and 2 in the CS + NA group (p<0.05) but not in the NA group. None of the surviving patients developed persistent infection. Conclusion Combination therapy with CS and NA induces the rapid resolution of inflammation leading to a rapid recovery of the liver function. When it is administered at a sufficiently early stage, it would have a survival benefit and prevent persistent infection in HBV-ALF.

Modern Management of Acute Liver Failure

Acute liver failure is a rare but life-threatening disease that can lead to progressive encephalopathy, intracranial hypertension, and multiorgan failure. In the developed world, the most common cause remains acetaminophen overdose, but there are still many cases in which there is acute liver failure of unknown etiology. The mainstay of acute liver failure management remains supportive care in the critical care setting. If supportive treatment does not stabilize the disease process, the patient may require emergent liver transplantation. This article summarizes the current management of acute liver failure.

Corticosteroid might reduce serum levels of pro-inflammatory cytokines in fulminant hepatitis: A case series

AIM

There are no beneficial therapies except for emergency liver transplantation for acute liver failure (ALF). However, in Japan, which has a serious problem in the shortage of donor livers, therapies other than transplantation must be further investigated for patients with ALF. Pro-inflammatory cytokines promoting tissue destruction are predominant at an early phase of ALF. Corticosteroid (CS) influences monocyte/macrophage differentiation, by suppressing pro-inflammatory genes, indicating CS treatment might be beneficial during the early phase of ALF. Our aim was to elucidate the efficacy of CS pulse therapy in decreasing pro-inflammatory cytokine levels in the early stage of ALF.

METHODS

Ten consecutive adult Japanese patients with fulminant hepatitis in the early stage, three treated with artificial liver support (ALS) and CS pulse therapy (ALS + CS group) and seven treated with ALS (ALS group), were enrolled. Clinical and biochemical data on admission were matched between the groups and retrospectively analyzed for serum concentrations of interleukin-6, tumor necrosis factor-α, and interleukin-1β over a 2-week period.

RESULTS

Mean cytokine levels on admission were not different between the two groups. Tumor necrosis factor-α was significantly reduced on day 7 in patients with CS. Serum levels of pro-inflammatory cytokines tended to be reduced in patients with CS compared to those without during the observation period, although the differences were not significant.

CONCLUSIONS

It might be possible that introduction of CS pulse therapy in the early stage of ALF could reduce levels of pro-inflammatory cytokines, which might inhibit the cascade of progression of ALF.

EASL Clinical Practical Guidelines on the management of acute (fulminant) liver failure

The term acute liver failure (ALF) is frequently applied as a generic expression to describe patients presenting with or developing an acute episode of liver dysfunction. In the context of hepatological practice, however, ALF refers to a highly specific and rare syndrome, characterised by an acute abnormality of liver blood tests in an individual without underlying chronic liver disease. The disease process is associated with development of a coagulopathy of liver aetiology, and clinically apparent altered level of consciousness due to hepatic encephalopathy. Several important measures are immediately necessary when the patient presents for medical attention. These, as well as additional clinical procedures will be the subject of these clinical practice guidelines.

Infectious complications, steroid use and timing for emergency liver transplantation in acute liver failure: analysis in a Japanese center

BACKGROUND

Corticosteroid (CS) has been introduced in most acute liver failure (ALF) patients for the purpose of suppressing pro-inflammatory cytokines in Japan where a shortage of donor livers exists, whereas CS use is evaluated to be no benefit in Western countries. In the present study, we aimed to clarify the association between infectious complications and CS use in ALF, and determine when to evaluate treatment response and consider the timing for switching to liver transplantation (LT).

METHODS

Corticosteroid was administered to patients in the early stage prospectively. Clinical and biochemical features of 110 adult patients were analyzed.

RESULTS

Corticosteroids were administered to 78 (71%) patients. The duration between start of CS and onset of infection was 17 ± 10 days. Multivariate analysis revealed that infection was associated with age >50 years (P = 0.034) and T-BIL >15 mg/dl (P < 0.001), and not with CS use (P = 0.10). Accumulative incidence of infection was not different between patients with and without CS (P = 0.18).

CONCLUSIONS

Corticosteroid use did not significantly increase the incidence of infection. Two weeks after introduction of CS is a critical point for evaluating treatment response, avoiding infectious complications and switching to LT.

Analysis of infectious complications and timing for emergency liver transplantation in autoimmune acute liver failure

BACKGROUND

Autoimmune hepatitis (AIH) is one of major etiologies of acute liver failure (ALF), and the survival rate without liver transplantation (LT) of patients with fulminant AIH is especially poor worldwide. We investigated the clinicopathological features of infectious complications in autoimmune ALF retrospectively and tried to determine when to continue corticosteroid (CS) treatment or abandon it for LT.

METHODS

Twenty patients with autoimmune ALF, comprising five severe hepatitis, 13 fulminant hepatitis and two late onset hepatic failure, were analyzed.

RESULTS

Corticosteroids were administered to 19 patients. Seventeen infectious complications were observed in 12 patients. The median (range) duration between the introduction of CS and onset of infection was 15 (10–41) days. There were no significant differences in clinicobiochemical features between patients with and without infection. Of 20 patients, eight (40%) recovered without LT, four (20%) received LT and eight (40%) died without LT. Dead or transplanted patients had more advanced liver failure on admission than recovered ones (P < 0.01).

CONCLUSIONS

Two-week after the introduction of CS is a critical point for avoiding infectious complications. Therefore, we should have evaluated efficacy of CS and performed LT by then at the latest in case of failure to improve.