Serum MicroRNA Signatures in Recovery From Acute and Chronic Liver Injury and Selection for Liver Transplantation

Serum microRNA-181a Expression Level in Patients with Acute Liver Failure and Its Correlation with Prognosis

Objective

This paper examined miR-181a expression in the serum of patients with acute liver failure (ALF) and investigated the impact of its expression in the prognosis of ALF patients.

Methods

A total of 112 ALF patients (ALF group) and 100 healthy controls during the same period (control group) were recruited as study subjects, and ALF patients were separated into the survival group and the death group. Serum ALT, AST, SCr, TBil, PTA, and International Normalized Ratio (INR) indices as well as serum miR-181a expression were assessed by using a fully automated biochemistry analyzer and RT-qPCR. Patients in the ALF group were evaluated using the Model for End-Stage Liver Disease (MELD) score. Correlation between serum miR-181a expression and MELD scores of ALF patients was processed by Pearson correlation analysis, and the diagnostic value of miR-181a level for the occurrence of ALF was estimated by ROC curve analysis. Multivariate logistic regression analysis was executed to assess the factors influencing the occurrence of death in ALF patients.

Results

ALF patients had higher levels of ALT, AST, TBiL, SCr, INR and miR-181a and lower PTA levels in comparison to healthy controls. Serum miR-181a expression level in ALF patients revealed a significant positive correlation with MELD score. Multivariate logistic regression analysis unveiled that TBil, INR, SCr, and miR-181a were the independent risk factors for the occurrence of death in ALF patients, and that PTA was an independent protective factor for the prognosis of ALF patients. miR-181a exhibited a favorable diagnostic value in ALF and its prognosis.

Conclusion

miR-181a expression is upregulated in the serum of ALF patients, and it can be utilized as an indicator for ALF diagnostic and prognostic assessment.

miRNA biomarkers to predict risk of primary non-function of fatty allografts and drug induced acute liver failures

Primary non-function (PNF) of an allograft defines an irreversible graft failure and although rare, constitutes a life-threatening condition that requires high-urgency re-transplantation. Equally, drug induced acute liver failures (ALF) are seldom but the rapid loss of hepatic function may require orthotropic liver transplantation (OLT). Recently, we reported the development of a rodent PNF-disease model of fatty allografts and showed that a dysfunctional Cori and Krebs cycle and inhibition of lactate transporters constitute a mechanism of PNF. Based on findings from the rat PNF-disease model, we selected 15 miRNA-biomarker candidates for clinical validation and performed RT-qPCRs in well-documented PNF cases following OLT of fatty allografts. To assess specificity and selectivity, we compared their regulation in pre- and intraoperative liver biopsies and pre- and post-operative blood samples of patients undergoing elective hepatobiliary surgery. Additionally, we assessed their regulation in drug induced ALF. We confirmed clinical relevance for 11 PNF-associated miRNAs and found expression of miRNA-27b-3p, miRNA-122-3p, miRNA-125a-5p, miRNA-125b-5p and miRNA-192-5p to correlate with the hepatic steatosis grades. Furthermore, we demonstrate selectivity and specificity for the biomarker candidates with opposite regulation of let-7b-5p, miRNA-122-5p, miRNA-125b-5p and miRNA-194-5p in blood samples of patients following successful OLTs and/or liver resection. Moreover, by considering findings from 21 independent ALF-studies, we observed nine PNF-associated miRNAs regulated in common. We report miRNAs highly regulated in PNF and ALF, and their common regulation in different diseases broadens the perspective as biomarker candidates. Our study warrants independent confirmation in randomized clinical trials.

microRNA associated with hepatocyte injury and systemic inflammation may predict adverse outcomes in cirrhotic patients

As the global prevalence of chronic liver disease continues to rise, the need to determine which patients will develop end-stage liver disease and require liver transplantation is increasingly important. However, current prognostic models perform sub-optimally. We aim to determine microRNA profiles associated with clinical decompensation and mortality/transplantation within 1 year. We examined microRNA expression profiles in plasma samples from patients across the spectrum of cirrhosis (n = 154), acute liver failure (ALF) (n = 22), sepsis (n = 20) and healthy controls (HC) (n = 20). We demonstrated that a microRNA-based model (miR-24 and -27a) associated with systemic inflammation differentiated decompensated cirrhosis states from compensated cirrhosis and HC (AUC 0.77 (95% CI 0.69-0.85)). 6 patients within the compensated cirrhosis group decompensated the subsequent year and their exclusion improved model performance (AUC 0.81 (95% CI 0.71-0.89)). miR-191 (associated with liver injury) predicted risk of mortality across the cohort when acutely decompensated and acute-on-chronic-liver failure patients were included. When they were excluded miR-24 (associated with systemic inflammation) predicted risk of mortality. Our findings demonstrate that microRNA associated with systemic inflammation and liver injury predict adverse outcomes in cirrhosis. miR-24 and -191 require further investigation as prognostic biomarkers and therapeutic targets for patients with liver disease.

The Role of Mechanistic Biomarkers in Understanding Acetaminophen Hepatotoxicity in Humans

Our understanding of the fundamental molecular mechanisms of acetaminophen (APAP) hepatotoxicity began in 1973 to 1974, when investigators at the US National Institutes of Health published seminal studies demonstrating conversion of APAP to a reactive metabolite that depletes glutathione and binds to proteins in the liver in mice after overdose. Since then, additional groundbreaking experiments have demonstrated critical roles for mitochondrial damage, oxidative stress, nuclear DNA fragmentation, and necrotic cell death as well. Over the years, some investigators have also attempted to translate these mechanisms to humans using human specimens from APAP overdose patients. This review presents those studies and summarizes what we have learned about APAP hepatotoxicity in humans so far. Overall, the mechanisms of APAP hepatotoxicity in humans strongly resemble those discovered in experimental mouse and cultured hepatocyte models, and emerging biomarkers also suggest similarities in liver repair. The data not only validate the first mechanistic studies of APAP-induced liver injury performed 50 years ago but also demonstrate the human relevance of numerous studies conducted since then. SIGNIFICANCE STATEMENT: Human studies using novel translational, mechanistic biomarkers have confirmed that the fundamental mechanisms of acetaminophen (APAP) hepatotoxicity discovered in rodent models since 1973 are the same in humans. Importantly, these findings have guided the development and understanding of treatments such as N-acetyl-l-cysteine and 4-methylpyrazole over the years. Additional research may improve not only our understanding of APAP overdose pathophysiology in humans but also our ability to predict and treat serious liver injury in patients.

The challenges and potential of microRNA-based therapy for patients with liver failure syndromes and hepatocellular carcinoma

INTRODUCTION

Morbidity and mortality from liver disease continues to rise worldwide. There are currently limited curative treatments for patients with liver failure syndromes, encompassing acute liver failure and decompensated cirrhosis states, outside of transplantation. Whilst there have been improvements in therapeutic options for patients with hepatocellular carcinoma (HCC), there remain challenges necessitating novel therapeutic agents. microRNA have long been seen as potential therapeutic targets but there has been limited clinical translation.

AREAS COVERED

We will discuss the limitations of conventional non-transplant management of patients with liver failure syndromes and HCC. We will provide an overview of microRNA and the challenges in developing and delivering microRNA-based therapeutic agents. We will finally provide an overview of microRNA-based therapeutic agents which have progressed to clinical trials.

EXPERT OPINION

microRNA have great potential to be developed into therapeutic agents due to their association with critical biological processes which govern health and disease. Utilizing microRNA sponges to target multiple microRNA associated with specific biological processes may improve their therapeutic efficacy. However, there needs to be significant improvements in delivery systems to ensure the safe delivery of microRNA to target sites and minimize systemic distribution. This currently significantly impacts the clinical translation of microRNA-based therapeutic agents.

The challenges and potential in developing microRNA associated with regeneration as biomarkers to improve prognostication for liver failure syndromes and hepatocellular carcinoma

INTRODUCTION

Determining the need for liver transplantation remains critical in the management of hepatocellular carcinoma (HCC) and liver failure syndromes (including acute liver failure and decompensated cirrhosis states). Conventional prognostic models utilize biomarkers of liver and non-liver failure and have limitations in their application. Novel biomarkers which predict regeneration may fulfil this niche. microRNA are implicated in health and disease and are present in abundance in the circulation. Despite this, they have not translated into mainstream clinical biomarkers.

AREAS COVERED

We will discuss current challenges in the prognostication of patients with liver failure syndromes as well as for patients with HCC. We will discuss biomarkers implicated with liver regeneration. We then provide an overview of the challenges in developing microRNA into clinically tractable biomarkers. Finally, we will provide a scoping review of microRNA which may have potential as prognostic biomarkers in liver failure syndromes and HCC.

EXPERT OPINION

Novel biomarkers are needed to improve prognostic models in liver failure syndromes and HCC. Biomarkers associated with liver regeneration are currently lacking and may fulfil this niche. microRNA have the potential to be developed into clinically tractable biomarkers but a consensus on standardizing methodology and reporting is required prior to large-scale studies.

miRNA-ome plasma analysis unveils changes in blood-brain barrier integrity associated with acute liver failure in rats

BACKGROUND

Hepatic encephalopathy (HE) symptoms associated with liver insufficiency are linked to the neurotoxic effects of ammonia and other toxic metabolites reaching the brain via the blood-brain barrier (BBB), further aggravated by the inflammatory response. Cumulative evidence documents that the non-coding single-stranded RNAs, micro RNAs (miRs) control the BBB functioning. However, miRs' involvement in BBB breakdown in HE is still underexplored. Here, we hypothesized that in rats with acute liver failure (ALF) or rats subjected to hyperammonemia, altered circulating miRs affect BBB composing proteins.

METHODS

Transmission electron microscopy was employed to delineate structural alterations of the BBB in rats with ALF (thioacetamide (TAA) intraperitoneal (ip.) administration) or hyperammonemia (ammonium acetate (OA) ip. administration). The BBB permeability was determined with Evans blue dye and sodium fluorescein assay. Plasma MiRs were profiled by Next Generation Sequencing (NGS), followed by in silico analysis. Selected miRs, verified by qRT-PCR, were examined in cultured rat brain endothelial cells. Targeted protein alterations were elucidated with immunofluorescence, western blotting, and, after selected miR mimics transfection, through an in vitro resistance measurement.

RESULTS

Changes in BBB structure and increased permeability were observed in the prefrontal cortex of TAA rats but not in the brains of OA rats. The NGS results revealed divergently changed miRNA-ome in the plasma of both rat models. The in silico analysis led to the selection of miR-122-5p and miR-183-5p with their target genes occludin and integrin β1, respectively, as potential contributors to BBB alterations. Both proteins were reduced in isolated brain vessels and cortical homogenates in TAA rats. We documented in cultured primary brain endothelial cells that ammonia alone and, in combination with TNFα increases the relative expression of NGS-selected miRs with a less pronounced effect of TNFα when added alone. The in vitro study also confirmed miR-122-5p-dependent decrease in occludin and miR-183-5p-related reduction in integrin β1 expression.

CONCLUSION

This work identified, to our knowledge for the first time, potential functional links between alterations in miRs residing in brain endothelium and BBB dysfunction in ALF.

The Evolution of Circulating Biomarkers for Use in Acetaminophen/Paracetamol-Induced Liver Injury in Humans: A Scoping Review

Acetaminophen (APAP) is a widely used drug, but overdose can cause severe acute liver injury. The first reports of APAP hepatotoxicity in humans were published in 1966, shortly after the development of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) as the first biomarkers of liver injury as opposed to liver function. Thus, the field of liver injury biomarkers has evolved alongside the growth in APAP hepatotoxicity incidence. Numerous biomarkers have been proposed for use in the management of APAP overdose patients in the intervening years. Here, we comprehensively review the development of these markers from the 1960s to the present day and briefly discuss possible future directions.

Liver Regeneration in Acute on Chronic Liver Failure

Liver regeneration is a multifaceted process by which the organ regains its original size and histologic organization. In recent decades, substantial advances have been made in our understanding of the mechanisms underlying regeneration following loss of hepatic mass. Liver regeneration in acute liver failure possesses several classic pathways, while also exhibiting unique differences in key processes such as the roles of differentiated cells and stem cell analogs. Here we summarize these unique differences and new molecular mechanisms involving the gut-liver axis, immunomodulation, and microRNAs with an emphasis on applications to the patient population through stem cell therapies and prognostication.

Acute Liver Failure: Biomarkers Evaluated by the Acute Liver Failure Study Group

There has been a growing interest in identifying prognostic biomarkers that alone or with available prognostic models (King's College Criteria, KCC; MELD and ALFSG Prognostic Index) would improve prognosis in acute liver failure (ALF) patients being assessed for liver transplantation. The Acute Liver Failure Study Group (ALFSG) has evaluated 15 potential prognostic biomarkers: serum AFP; apoptosis-associated proteins; serum actin-free Gc-globulin; serum glycodeoxycholic acid; sRAGE/RAGE ligands; plasma osteopontin; circulating MBL, M-, L-, H-ficolin and CL-1; plasma galectin-9; serum FABP1; serum Lct2; miRNAs; factor V; thrombocytopenia, and sCD163. The ALFSG also has reported on 4 susceptibility biomarkers: keratins 8 and 18 (K8/K18) gene variants; polymorphisms of genes encoding putative APAP-metabolizing enzymes ( UGT1A1 , UGT 1A0 , UGT 2B15 , SULT1A1 , CYP2E1 , and CYP3A5 ) as well as CD44 and BHMT1 ; single nucleotide polymorphisms (SNPs) of genes associated with human behavior, rs2282018 in the arginine vasopressin ( AVP ) gene and rs11174811 in the AVP receptor 1A gene. Finally, rs2277680 of the CSCL16 gene in HBV-ALF patients. In conclusion, we have reviewed the prognostic and susceptibility biomarkers studied by the ALFSG. We suggest that a better approach to predicting the clinical outcome of an ALF patient will require a combination of biomarkers of pathogenic processes such as cell death, hepatic regeneration, and degree of inflammation that could be incorporated into prognostic models such as KCC, MELD or ALFSG PI.

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.

Artificial liver support systems for hepatitis B virus-associated acute-on-chronic liver failure: A meta-analysis of the clinical literature

To evaluate the short-term and long-term survival efficacy of an artificial liver support system (ALSS) in patients with acute-on-chronic liver failure (ACLF). A systematic search was performed for relevant published data in PubMed, Web of Science and Cochrane Library databases. Studies that evaluated the efficacy of ALSS in patients with ACLF and provided the short-term or long-term survival rate were included. A total of 10 studies involving 3685 patients were included in this analysis. The pooled 28-day survival rate and 90-day survival rate were 68.7% (95% CI: 64.5%-72.9%) and 53.4% (95% CI: 45.5%-61.4%), respectively. The pooled estimates of the OR for the 28-day and 90-day survival rates between the ALSS group and the control group were 1.91 (95% CI: 1.21-3.04) and 1.41 (95% CI: 1.17-1.70), respectively. Subgroup analysis showed that patients treated with lower levels of TBIL and MELD scores had a higher 28-day survival rate (χ²  = 15.75, p < 0.01; χ²  = 13.80, p < 0.01). The present meta-analysis suggests that ALSS treatment could remarkably improve short-term survival rates in HBV-ACLF patients, which implies that treatment with ALSS may help to reduce high mortality. Further prospective randomized trials are needed to validate these findings.

The Baveno VII concept of cirrhosis recompensation

Traditionally, the progression from compensated to decompensated cirrhosis has been regarded as a point of no return in the natural history of the disease. However, this point of view is increasingly being challenged by new evidence on disease regression and hepatic recompensation upon suppression/cure of the underlying aetiology. In order to create a uniform definition of recompensated cirrhosis, standardised criteria have been set out by the Baveno VII consensus, which include the removal of the primary aetiological factor, the resolution of any decompensating events and a sustained improvement in hepatic function. Initial insights into the concept of hepatic recompensation come from previous studies, which have demonstrated that a cure/suppression of the underlying aetiology in patients with prior decompensation leads to significant clinical improvements and favourable outcomes and can even enable the delisting of transplant candidates. Nevertheless, future studies are required to shed light on the natural history of hepatic recompensation, assess modifying factors and potential non-invasive biomarkers of recompensation and explore the molecular mechanisms of disease regression.

Acute liver failure

PURPOSE OF REVIEW

Present an outline of acute liver failure, from its definition to its management in critical care, updated with findings of selected newer research.

RECENT FINDINGS

Survival of patients with acute liver failure has progressively improved. Intracranial hypertension complicating hepatic encephalopathy is now much less frequent than in the past and invasive ICP monitoring is now rarely used. Early renal replacement therapy and possibly therapeutic plasma exchange have consolidated their role in the treatment. Further evidence confirms the low incidence of bleeding in these patients despite striking abnormalities in standard tests of coagulation and new findings of abnormalities on thromboelastographic testing. Specific coagulopathy profiles including an abnormal vWF/ADAMTS13 ratio may be associated with poor outcome and increased bleeding risk. Use of N-acetylcysteine in nonparacetamol-related cases remains unsupported by robust clinical evidence. New microRNA-based prognostic markers to select patients for transplantation are described but are still far from widespread clinical applicability; imaging-based prognostication tools are also promising. The use of extracorporeal artificial liver devices in clinical practice is yet to be supported by evidence.

SUMMARY

Medical treatment of patients with acute liver failure is now associated with significantly improved survival. Better prognostication and selection for emergency liver transplant may further improve care for these patients.

Insight into microRNAs-Mediated Communication between Liver and Brain: A Possible Approach for Understanding Acute Liver Failure?

Acute liver failure (ALF) is a life-threatening consequence of hepatic function rapid loss without preexisting liver disease. ALF may result in a spectrum of neuropsychiatric symptoms that encompasses cognitive impairment, coma, and often death, collectively defined as acute hepatic encephalopathy. Micro RNAs are small non-coding RNAs that modulate gene expression and are extensively verified as biomarker candidates in various diseases. Our systematic literature review based on the last decade's reports involving a total of 852 ALF patients, determined 205 altered circulating miRNAs, of which 25 miRNAs were altered in the blood, regardless of study design and methodology. Selected 25 miRNAs, emerging predominantly from the analyses of samples obtained from acetaminophen overdosed patients, represent the most promising biomarker candidates for a diagnostic panel for symptomatic ALF. We discussed the role of selected miRNAs in the context of tissue-specific origin and its possible regulatory role for molecular pathways involved in blood-brain barrier function. The defined several common pathways for 15 differently altered miRNAs were relevant to cellular community processes, indicating loss of intercellular, structural, and functional components, which may result in blood-brain barrier impairment and brain dysfunction. However, a causational relationship between circulating miRNAs differential expression, and particular clinical features of ALF, has to be demonstrated in a further study.

Getting immunosuppression just right: the role of clinical biomarkers in predicting patient response post solid organ transplantation

INTRODUCTION

Actually, immunosuppression selection isn't based on individual immune alloreactivity, and immunosuppressive drug dosing is mainly based on the development of toxicity and the achievement of specific target concentrations. Since a successful outcome requires optimal patient risk stratification and treatment, several groups have evaluated candidate biomarkers that have shown promise in the assessment of individual immune responses, the prediction of personal pharmacodynamic effects of immunosuppressive drugs and the prognosis and diagnosis of graft outcomes..

AREAS COVERED

This review includes biomarkers that the Scientific Community in Solid Organ Transplantation currently considers to have potential as diagnostic and prognostic biomarkers of graft evolution. We have focused on recent scientific advances and expert recommendations regarding the role of specific and non-specific pharmacodynamic biomarkers that are mainly involved in the T-cell-mediated response.

EXPERT OPINION

Integral pharmacologic monitoring that combines pharmacokinetics, pharmacogenetics and predictive pharmacodynamic biomarkers may provide crucial information and allow personal adjustment of immunosuppressive drugs at an early stage before severe adverse events ensue. Multicentre, randomized, prospective and interventional trials are needed to fine tune the established cut-off values for each biomarker and the optimal monitoring frequency for each biomarker and to accurately evaluate possible clinical confounding factors to enable correct clinical qualification.

Transcriptional Analysis of Liver Tissue Identifies Distinct Phenotypes of Indeterminate Pediatric Acute Liver Failure

Many patients with indeterminate pediatric acute liver failure (PALF) have evidence of T-cell driven immune injury; however, the precise inflammatory pathways are not well defined. We have characterized the hepatic cytokine and transcriptional signatures of patients with PALF. A retrospective review was performed on 22 children presenting with indeterminate (IND-PALF; n = 17) or other known diagnoses (DX-PALF; n = 6) with available archived liver tissue. Specimens were stained for clusters of differentiation 8 (CD8) T cells and scored as dense, moderate, or minimal. Measurement of immune analytes and RNA sequencing (RNA-seq) was performed on whole-liver tissue. Immune analyte data were analyzed by principal component analysis, and RNA-seq was analyzed by unsupervised hierarchical clustering, differential gene expression, and gene-set enrichment analysis. Most patients with IND-PALF (94%) had dense/moderate CD8 staining and were characterized by Th1 immune analytes including tumor necrosis factor α, interferon γ (IFN-γ), interleukin (IL) 1β, IL-12, C-X-C motif chemokine ligand (CXCL) 9, and CXCL12. Transcriptional analyses identified two transcriptional PALF phenotypes. Most patients in group 1 (91%) had IND-PALF and dense/moderate CD8 staining. This group was characterized by increased expression of genes and cell subset-specific signatures related to innate inflammation, T-cell activation, and antigen stimulation. Group 1 expressed significantly higher levels of gene signatures for regulatory T cells, macrophages, Th1 cells, T effector memory cells, cytotoxic T cells, and activated dendritic cells (adjusted P < 0.05). In contrast, patients in group 2 exhibited increased expression for genes involved in metabolic processes. Conclusion: Patients with IND-PALF have evidence of a Th1-mediated inflammatory response driven by IFN-γ. Transcriptional analyses suggest that a complex immune network may regulate an immune-driven PALF phenotype with less evidence of metabolic processes. These findings provide insight into mechanisms of hepatic injury in PALF, areas for future research, and potential therapeutic targets.

A novel microRNA-based prognostic model outperforms standard prognostic models in patients with acetaminophen-induced acute liver failure

BACKGROUND & AIMS

Acetaminophen (APAP)-induced acute liver failure (ALF) remains the most common cause of ALF in the Western world. Conventional prognostic models, utilising markers of liver injury and organ failure, lack sensitivity for mortality prediction. We previously identified a microRNA signature that is associated with successful regeneration post-auxiliary liver transplant and with recovery from APAP-ALF. Herein, we aimed to use this microRNA signature to develop outcome prediction models for APAP-ALF.

METHODS

We undertook a nested, case-control study using serum samples from 194 patients with APAP-ALF enrolled in the US ALF Study Group registry (1998-2014) at early (day 1-2) and late (day 3-5) time-points. A microRNA qPCR panel of 22 microRNAs was utilised to assess microRNA expression at both time-points. Multiple logistic regression was used to develop models which were compared to conventional prognostic models using the DeLong method.

RESULTS

Individual microRNAs confer limited prognostic value when utilised in isolation. However, incorporating them within microRNA-based outcome prediction models increases their clinical utility. Our early time-point model (AUC = 0.78, 95% CI 0.71-0.84) contained a microRNA signature associated with liver regeneration and our late time-point model (AUC = 0.83, 95% CI 0.76-0.89) contained a microRNA signature associated with cell-death. Both models were enhanced when combined with model for end-stage liver disease (MELD) score and vasopressor use and both outperformed the King's College criteria. The early time-point model combined with clinical parameters outperformed the ALF Study Group prognostic index and the MELD score.

CONCLUSIONS

Our findings demonstrate that a regeneration-linked microRNA signature combined with readily available clinical parameters can outperform existing prognostic models for ALF in identifying patients with poor prognosis who may benefit from transplantation.

LAY SUMMARY

While acute liver failure can be reversible, some patients will die without a liver transplant. We show that blood test markers that measure the potential for liver recovery may help improve identification of patients unlikely to survive acute liver failure who may benefit from a liver transplant.

Role of Noncoding RNAs in Acetaminophen-Induced Liver Injury

Genomic and transcriptomic analyses have well established that the major fraction of the mammalian genome is transcribed into different classes of RNAs ranging in size from a few nucleotides to hundreds of thousands of nucleotides, which do not encode any protein. Some of these noncoding RNAs (ncRNAs) are directly or indirectly linked to the regulation of expression or functions of 25,000 proteins coded by <2% of the human genome. Among these regulatory RNAs, microRNAs are small (2125 nucleotides) RNAs that are processed from precursor RNAs that have stemloop structure, whereas noncoding RNAs >200 nucleotides are termed long noncoding RNAs (lncRNAs). Circular RNAs (circRNAs) are newly identified lncRNA members that are generated by back-splicing of primary transcripts. The functions of ncRNAs in modulating liver toxicity of xenobiotics are emerging only recently. Acetaminophen (N-acetyl-para-aminophenol, paracetamol or APAP) is a safe analgesic and antipyretic drug at the therapeutic dose. However, it can cause severe liver toxicity that may lead to liver failure if overdosed or combined with alcohol, herbs, or other xenobiotics. This review discusses the role of ncRNAs in acetaminophen metabolism, toxicity, and liver regeneration after APAP-induced liver injury (AILI).