Update on the management of acute liver failure

Acute liver failure: A practical update

Acute liver failure is a rare and dynamic condition, with a broad aetiology and an incompletely understood pathophysiology. Management of this life-threatening disease requires critical care and organ support and frequently early liver transplantation. Proper identification, prevention and treatment of complications such as intracranial hypertension and sepsis are critical to optimising outcomes. The identification of the cause of acute liver failure and the prompt initiation of the aetiological treatment can also improve prognosis. Survival has progressively improved in parallel to advances in medical treatment. Intracranial hypertension complicating hepatic encephalopathy is less frequent than in the past and intracranial pressure monitoring now relies on non-invasive techniques. Current prognostic models have good accuracy to identify patients who will die without liver transplantation but are not able to identify those in whom transplantation is futile. New prognostic markers to select patients for transplantation are still in the pipeline. Therapeutic plasma exchange and, in some centers, early renal replacement therapy are well established treatments for the disease. The use of other artificial liver devices in clinical practice is not supported by evidence. This review is intended to provide a clinical update on the management of acute liver failure, incorporating the most recent advances in the field.

Effect of P53 nuclear localization mediated by G3BP1 on ferroptosis in acute liver failure

This study investigated whether G3BP1 could regulate ferroptosis in hepatocytes during ALF by affecting the entry of P53 into the nucleus. Promoting G3BP1 expression could inhibit P53 entry by binding to the nuclear localization sequence of P53. The inhibition of SLC7A11 transcription was weakened after blocking of P53 binding to the promoter region of the SLC7A11 gene. The SLC7A11-GSH-GPX4 antiferroptotic pathway was subsequently activated, and the level of ferroptosis in ALF hepatocytes was inhibited.

Lysophosphatidylcholines modulate immunoregulatory checkpoints in peripheral monocytes and are associated with mortality in people with acute liver failure

BACKGROUND & AIMS

Acute liver failure (ALF) is a life-threatening disease characterised by high-grade inflammation and immunoparesis, which is associated with a high incidence of death from sepsis. Herein, we aimed to describe the metabolic dysregulation in ALF and determine whether systemic immune responses are modulated via the lysophosphatidylcholine (LPC)-autotaxin (ATX)-lysophosphatidylcholinic acid (LPA) pathway.

METHODS

Ninety-six individuals with ALF, 104 with cirrhosis, 31 with sepsis and 71 healthy controls (HCs) were recruited. Pathways of interest were identified by multivariate statistical analysis of proton nuclear magnetic resonance spectroscopy and untargeted ultraperformance liquid chromatography-mass spectrometry-based lipidomics. A targeted metabolomics panel was used for validation. Peripheral blood mononuclear cells were cultured with LPA 16:0, 18:0, 18:1, and their immune checkpoint surface expression was assessed by flow cytometry. Transcript-level expression of the LPA receptor (LPAR) in monocytes was investigated and the effect of LPAR antagonism was also examined in vitro.

RESULTS

LPC 16:0 was highly discriminant between ALF and HC. There was an increase in ATX and LPA in individuals with ALF compared to HCs and those with sepsis. LPCs 16:0, 18:0 and 18:1 were reduced in individuals with ALF and were associated with a poor prognosis. Treatment of monocytes with LPA 16:0 increased their PD-L1 expression and reduced CD155, CD163, MerTK levels, without affecting immune checkpoints on T and NK/CD56+T cells. LPAR1 and 3 antagonism in culture reversed the effect of LPA on monocyte expression of MerTK and CD163. MerTK and CD163, but not LPAR genes, were differentially expressed and upregulated in monocytes from individuals with ALF compared to controls.

CONCLUSION

Reduced LPC levels are biomarkers of poor prognosis in individuals with ALF. The LPC-ATX-LPA axis appears to modulate innate immune response in ALF via LPAR1 and LPAR3. Further investigations are required to identify novel therapeutic agents targeting these receptors.

IMPACT AND IMPLICATIONS

We identified a metabolic signature of acute liver failure (ALF) and investigated the immunometabolic role of the lysophosphatidylcholine-autotaxin-lysophosphatidylcholinic acid pathway, with the aim of finding a mechanistic explanation for monocyte behaviour and identifying possible therapeutic targets (to modulate the systemic immune response in ALF). At present, no selective immune-based therapies exist. We were able to modulate the phenotype of monocytes in vitro and aim to extend these findings to murine models of ALF as a next step. Future therapies may be based on metabolic modulation; thus, the role of specific lipids in this pathway require elucidation and the relative merits of autotaxin inhibition, lysophosphatidylcholinic acid receptor blockade or lipid-based therapies need to be determined. Our findings begin to bridge this knowledge gap and the methods used herein could be useful in identifying therapeutic targets as part of an experimental medicine approach.

Stress granules inhibit endoplasmic reticulum stress-mediated apoptosis during hypoxia-induced injury in acute liver failure

BACKGROUND

Stress granules (SGs) could be formed under different stimulation to inhibit cell injury.

AIM

To investigate whether SGs could protect hepatocytes from hypoxia-induced damage during acute liver failure (ALF) by reducing endoplasmic reticulum stress (ERS) mediated apoptosis.

METHODS

The agonist of SGs, arsenite (Ars) was used to intervene hypoxia-induced hepatocyte injury cellular model and ALF mice models. Further, the siRNA of activating transcription factor 4 (ATF4) and SGs inhibitor anisomycin was then used to intervene in cell models.

RESULTS

With the increase of hypoxia time from 4 h to 12 h, the levels of HIF-1α, ERS and apoptosis gradually increased, and the expression of SGs marker G3BP1 and TIA-1 was increased and then decreased. Compared with the hypoxia cell model group and ALF mice model, the levels of HIF-1α, apoptosis and ERS were increased in the Ars intervention group. After siRNA-ATF4 intervention, the level of SGs in cells increased, and the levels of HIF-1α, ERS and apoptosis decreased. Compared with the siRNA-ATF4 group, the levels of G3BP1 in the siRNA-ATF4+anisomycin group were decreased, and the levels of HIF-1α, ERS and apoptosis were increased. Moreover, compared with the ALF group, the degree of liver injury and liver function, the levels of HIF-1α, ERS and apoptosis in the Ars intervention group were decreased, the level of SGs was increased.

CONCLUSION

SGs could protect hepatocytes from hypoxia-induced damage during ALF by reducing ERS-mediated apoptosis.

Upregulated microRNA-450b-5p represses the development of acute liver failure via modulation of liver function, inflammatory response, and hepatocyte apoptosis

OBJECTIVE

It has been evidenced that microRNAs (miRs) exert crucial effects on acute liver failure (ALF), while the detailed function of miR-450b-5p in ALF progression remained obscure. The purpose of this research was to unravel the regulatory mechanism of miR-450b-5p in ALF via modulating Mouse Double Minute 2 protein (MDM2).

METHODS

ALF was induced in mice by intraperitoneal injection of d-galactosamine ( d-GalN) and lipopolysaccharide (LPS). Adenoviruses containing overexpressed miR-450b-5p, MDM2 shRNA, and overexpressed MDM2 sequences were utilized to manipulate miR-450b-5p and MDM2 expression in the liver before the mice were treated with d-GalN/LPS-induced ALF. Subsequently, miR-450b-5p and MDM2 expression levels in liver tissues of ALF mice were examined. Serum biochemical parameters of liver function were tested, serum inflammatory factors were assessed, and the histopathological changes and hepatocyte apoptosis in liver tissues were observed. The relation between miR-450b-5p and MDM2 was verified.

RESULTS

In ALF mice, miR-450b-5p was low-expressed while MDM2 was high-expressed. The upregulation of miR-450b-5p or downregulation of MDM2 could alleviate liver function, mitigate the serum inflammatory response and pathological changes in liver tissues, as well as inhibit the apoptosis of hepatocytes. MiR-450b-5p targeted MDM2. MDM2 overexpression reversed the repressive effects of elevated miR-450b-5p on ALF.

CONCLUSION

The upregulated miR-450b-5p blocks the progression of ALF via targeting MDM2. This study contributes to affording novel therapeutic targets for ALF treatment.

Flos Carthami Exerts Hepatoprotective Action in a Rat Model of Alcoholic Liver Injury via Modulating the Metabolomics Profile

This study was intended to identify the shifts in the metabolomics profile of the hepatic tissue damaged by alcohol consumption and verify the potential restorative action of flos carthami (the flowers of Carthamus tinctorius, FC) in the protection of alcohol-induced injury by attenuating the level of identified metabolites. Rats were treated with FC and subsequently subjected to alcohol administration. The serum samples were subjected to liquid chromatography-mass spectrometry (LC-MS)-based metabolomics followed by statistical and bioinformatics analyses. The clustering of the samples showed an obvious separation in the principal component analysis (PCA) plot, and the scores plot of the orthogonal partial least squares-discriminant analysis (OPLS-DA) model allowed the distinction among the three groups. Among the 3211 total metabolites, 1088 features were significantly different between the control and alcohol-treated groups, while 367 metabolites were identified as differential metabolites between the alcohol- and FC-treated rat groups. Time series clustering approach indicated that 910 metabolites in profile 6 were upregulated by alcohol but subsequently reversed by FC treatment; among them, the top 10 metabolites based on the variable importance in projection (VIP) scores were 1-methyladenine, phenylglyoxylic acid, N-acetylvaline, mexiletine, L-fucose, propylthiouracil, dopamine 4-sulfate, isoleucylproline, (R)-salsolinol, and monomethyl phthalate. The Pearson correlation analysis and network construction revealed 96 hub metabolites that were upregulated in the alcohol liver injury model group but were downregulated by FC. This study confirmed the hepatoprotective effects of FC against alcohol-induced liver injury and the related changes in the metabolic profiles, which will contribute to the understanding and the treatment of alcohol-induced acute liver injury.

Bridging to Allotransplantation-Is Pig Liver Xenotransplantation the Best Option?

In the past 20 y, the number of patients in the United States who died while waiting for a human donor liver totaled >52 000. The median national wait time for patients with acute liver failure and the most urgent liver transplant listing was 7 d in 2018. The need for a clinical "bridge" to allotransplantation is clear. Current options for supporting patients with acute liver failure include artificial liver support devices, extracorporeal liver perfusion, and hepatocyte transplantation, all of which have shown mixed results with regard to survival benefit and are largely experimental. Progress in the transplantation of genetically engineered pig liver grafts in nonhuman primates has grown steadily, with survival of the pig graft extended to almost 1 mo in 2017. Further advances may justify consideration of a pig liver transplant as a clinical bridge to allotransplantation. We provide a brief history of pig liver xenotransplantation, summarize the most recent progress in pig-to-nonhuman primate liver transplantation models, and suggest criteria that may be considered for patient selection for a clinical trial of bridging by genetically engineered pig liver xenotransplantation to liver allotransplantation.

Analysis of the safety of pretransplant corticosteroid therapy in patients with acute liver failure and late-onset hepatic failure in Japan

Background and Aim

In Japan, corticosteroids have been commonly used as a part of multidisciplinary therapy for patients with acute liver failure and late‐onset hepatic failure. However, there is controversy regarding the development of infections and other complications. In this study, the influence of corticosteroids on patient outcomes after liver transplantation was investigated.

Methods

This study included 167 patients with acute liver failure and late‐onset hepatic failure who underwent liver transplantation between 2010 and 2015. The effects of pretransplant corticosteroid therapy on patient outcomes were evaluated using a database constructed by the subcommittee for fulminant hepatitis in the Intractable Hepato‐Biliary Diseases Study Group of Japan.

Results

The subacute type and the median total bilirubin levels were higher in those receiving corticosteroids than in those not receiving corticosteroids. Although infections tended to be higher in patients receiving corticosteroids, pretransplant corticosteroid administration did not affect the survival rates. The duration from corticosteroid initiation to liver transplantation was longer in patients who developed infections. The survival rates, however, did not differ between patients with and without infections.

Conclusions

Corticosteroids were administered to patients with poor prognoses. Otherwise, the overall outcome in those administered corticosteroids was not significantly different from that in those administered without corticosteroids. Although infectious complications tended to occur, they were generally controllable and nonfatal. Pretransplant corticosteroid therapy may be permissible, with regarding for infections and performed within the minimum duration.

Efficacy and safety of liver support devices in acute and hyperacute liver failure: a systematic review and network meta-analysis

Acute liver failure (ALF) is a potentially life-threatening condition. Liver support therapies can be applied as a bridging-to-transplantation or bridging-to-recovery; however, results of clinical trials are controversial. Our aim was to compare liver support systems in acute and hyperacute liver failure with network meta-analysis. After systematic search, randomized controlled trials (RCT) comparing liver support therapies in adults with acute or hyperacute liver failure were included. In-hospital mortality was the primary outcome, the secondary outcomes were hepatic encephalopathy and mortality-by-aetiology. A Bayesian-method was used to perform network meta-analysis and calculate surface under the cumulative ranking curve (SUCRA) values to rank interventions. Eleven RCTs were included. BioLogic-DT and molecular adsorbent recirculating system (MARS) resulted in the lowest mortality (SUCRAs: 76% and 73%, respectively). In non-paracetamol-poisoned patients, BioLogic-DT, charcoal hemoperfusion and MARS may be equally efficient regarding mortality (SUCRAs: 53%, 52% and 52%, respectively). Considering hepatic encephalopathy, extracorporeal liver assist device (ELAD) may be the most effective option (SUCRA: 78%). However, in pairwise meta-analysis, there were no statistically significant differences between the interventions in the outcomes. In conclusion, MARS therapy seems to be the best available option in reducing mortality. Further research is needed on currently available and new therapeutic modalities. (CRD42020160133).

SEPSIS. Educational and Best Practice Frontiers. Beyond the Boundaries of Fatality, Enhancing Clinical Skills and Precision Medicine

Dissemination and exploitation of knowledge regarding affordable clinical skills and innovative precision medicine, two current topics in active development in medicine, may contribute to improve also sepsis management. Sepsis is a life-threatening organ dysfunction due to a dysregulated host response to infection. Sepsis is strongly related to all body organs or to systemic diseases and to the quality of the best-practice in use, which is particularly critical in surgical or intervention techniques. Trauma, surgical and mini-invasive procedures, vascular or endoscopic interventions, otolaryngology, obstetrics-gynecological and urological procedures, malnutrition, dental, skin, chronic liver, kidney and respiratory disease are frequently involved. Accordingly, apart from the clinical risk analysis and management of the process of care, the actual factors that may be easily neglected are the techniques used, the personal skills of the health professionals and the quality of the equipment. The quest for biomarkers consistent with the unmet needs of medical doctors and of their patient and the efforts for overcoming bacterial antibiotic resistances are currently the main foci of medical research. In addition, in this regard, research and innovation would benefit from greater knowledge, skills and use of bioinformatics and omics. The caveats related to in-silico approaches must be flagged: algorithms may equally warrant scientific innovations or hide the lack of them; a patient is more than a set of covariates. Epidemiology and prevention includes all the actions suitable for achieving an adequate hygiene and immunization of populations and for safer hospital policies and procedures during Patients’ stays. In any subset, the most unresolved critical point in sepsis is a timely diagnosis. This is impaired by low degrees of suspicion for the possibility of emerging sepsis, by the shortage of use of the simplest microbiological testing but, equally or more, by the insufficient diffusion of non-invasive imaging skills suitable to detect and monitor the emerging sites and sources of infection. In primary care, in emergency facilities, in hospital wards and in intensive care units, inclusion of appropriate knowledge, skills, expertise and imaging equipment must be extended as much as possible. The low cost of UltraSound machines and of increasing bioinformatics literacy by e-learning, makes such investments affordable even in limited-resources contexts. Frontier educational and best practice intervention enhancing affordable clinical skills and innovative precision medicine may lead beyond the boundaries of fatal outcomes in sepsis.

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End-stage liver failure: filling the treatment gap at the intensive care unit

End-stage liver failure is a condition of collapsing liver function with mortality rates up to 80. Liver transplantation is the only lifesaving therapy. There is an unmet need for therapy to extend the waiting time for liver transplantation or regeneration of the native liver. Here we review the state-of-the-art of non-cell based and cell-based artificial liver support systems, cell transplantation and plasma exchange, with the first therapy relying on detoxification, while the others aim to correct also other failing liver functions and/or modulate the immune response. Meta-analyses on the effect of non-cell based systems show contradictory outcomes for different types of albumin purification devices. For bioartificial livers proof of concept has been shown in animals with liver failure. However, large clinical trials with two different systems did not show a survival benefit. Two clinical trials with plasma exchange and one with transplantation of mesenchymal stem cells showed positive outcomes on survival. Detoxification therapies lack adequacy for most patients. Correction of additional liver functions, and also modulation of the immune system hold promise for future therapy of liver failure.