Review article: the current management of acute liver failure

Hepatoprotective effect of amifostine and WR-1065 on acetaminophen-induced liver toxicity on Wistar rats

PURPOSE

The most important problem with acetaminophen is its hepatotoxicity. N-acetylcysteine (NAC) is used to treat the hepatotoxicity of acetaminophen. Due to the structural similarities of this compound with amifostine, we decided to test the effect of this substance and its metabolite, WR-1065, on the hepatotoxicity of acetaminophen.

METHODS

The single-dose method contained 1. Control; 2. Acetaminophen (1 g/kg, gavage); 3-5. Acetaminophen + amifostine (100, 200, 400 mg/kg, i.p.); 6-8. Acetaminophen + WR-1065 (50, 100, 200 mg/kg, i.p.); and 9. Acetaminophen + NAC (100, 200 mg/kg, i.p.). The multiple-dose method included the same groups: amifostine (50, 100, 200 mg/kg), WR-1065 (25, 50, 100 mg/kg), and NAC (100 mg/kg). Then, animals were sacrificed, and blood samples were collected for measuring ALT, AST, ALP, and T-Bil, liver tissue for histopathological examination, MDA, and GSH amounts.

RESULTS

Acetaminophen increased the levels of MDA, T-Bil, ALT, AST, and ALP, decreased GSH levels, and augmented necrosis, neutrophils, lymphocytes, and macrophages in the port space in single-dose and multiple-dose studies. Amifostine and WR-1065 significantly reduced the levels of MDA, T-Bil, ALT, AST, ALP, increased GSH content, and ameliorated histopathological alterations in a single-dose and multiple-dose method compared to the acetaminophen group. Moreover, NAC caused a significant decrease in the levels of MDA, T-Bil, ALT, AST, and ALP, and reduced GSH amounts in single-dose and multiple-dose studies.

CONCLUSION

Amifostine and WR-1065 as antioxidant and hepatoprotective compounds are effective in reducing acetaminophen-induced hepatotoxicity with a similar effect to NAC and can be administered as an adjunct in the treatment of acetaminophen overdose.

Inhibition of ALK3-mediated signalling pathway protects against acetaminophen-induced liver injury

Acetaminophen (APAP)-induced liver injury is one of the most prevalent causes of acute liver failure (ALF). We assessed the role of the bone morphogenetic protein (BMP) type I receptors ALK2 and ALK3 in APAP-induced hepatotoxicity. The molecular mechanisms that regulate the balance between cell death and survival and the response to oxidative stress induced by APAP was assessed in cultured human hepatocyte-derived (Huh7) cells treated with pharmacological inhibitors of ALK receptors and with modulated expression of ALK2 or ALK3 by lentiviral infection, and in a mouse model of APAP-induced hepatotoxicity. Inhibition of ALK3 signalling with the pharmacological inhibitor DMH2, or by silencing of ALK3, showed a decreased cell death both by necrosis and apoptosis after APAP treatment. Also, upon APAP challenge, ROS generation was ameliorated and, thus, ROS-mediated JNK and P38 MAPK phosphorylation was reduced in ALK3-inhibited cells compared to control cells. These results were also observed in an experimental model of APAP-induced ALF in which post-treatment with DMH2 after APAP administration significantly reduced liver tissue damage, apoptosis and oxidative stress. This study shows the protective effect of ALK3 receptor inhibition against APAP-induced hepatotoxicity. Furthermore, findings obtained from the animal model suggest that BMP signalling might be a new pharmacological target for the treatment of ALF.

Oral magnesium prevents acetaminophen-induced acute liver injury by modulating microbial metabolism

Acetaminophen overuse is a common cause of acute liver failure (ALF). During ALF, toxins are metabolized by enzymes such as CYP2E1 and transformed into reactive species, leading to oxidative damage and liver failure. Here, we found that oral magnesium (Mg) alleviated acetaminophen-induced ALF through metabolic changes in gut microbiota that inhibit CYP2E1. The gut microbiota from Mg-supplemented humans prevented acetaminophen-induced ALF in mice. Mg exposure modulated Bifidobacterium metabolism and enriched indole-3-carboxylic acid (I3C) levels. Formate C-acetyltransferase (pflB) was identified as a key Bifidobacterium enzyme involved in I3C generation. Accordingly, a Bifidobacterium pflB knockout showed diminished I3C generation and reduced the beneficial effects of Mg. Conversely, treatment with I3C or an engineered bacteria overexpressing Bifidobacterium pflB protected against ALF. Mechanistically, I3C bound and inactivated CYP2E1, thus suppressing formation of harmful reactive intermediates and diminishing hepatocyte oxidative damage. These findings highlight how interactions between Mg and gut microbiota may help combat ALF.

Advances in the study of acetaminophen-induced liver injury

Acetaminophen (APAP) overdose is a significant cause of drug-induced liver injury and acute liver failure. The diagnosis, screening, and management of APAP-induced liver injury (AILI) is challenging because of the complex mechanisms involved. Starting from the current studies on the mechanisms of AILI, this review focuses on novel findings in the field of diagnosis, screening, and management of AILI. It highlights the current issues that need to be addressed. This review is supposed to summarize the recent research progress and make recommendations for future research.

Pien Tze Huang attenuated acetaminophen-induced liver injury by autophagy mediated-NLRP3 inflammasome inhibition

ETHNOPHARMACOLOGICAL RELEVANCE

Pien Tze Huang is a classic traditional Chinese medicinal product, used for inflammatory diseases as stated in Chinese Pharmacopoeia. In particular, it is effective in treating liver diseases and pro-inflammatory conditions. Acetaminophen (APAP) is a widely used analgesic drug, but its over-dose is associated with acute liver failure where the clinical approved antidote treatment is limited. Inflammation has been considered as one of the therapeutic targets against APAP-induced liver injury.

AIM OF THE STUDY

We aimed to explore the therapeutic potential of Pien Tze Huang tablet (PTH) on protecting liver against APAP-induced liver injury through its strong anti-inflammatory pharmacological action.

MATERIALS AND METHODS

Wild-type C57BL/6 mice were given PTH (75, 150 and 300 mg/kg) by oral gavage 3 days before the APAP injection (400 mg/kg). The protective effect of PTH was assessed by aspartate aminotransferase (AST) and alanine transaminase (ALT) levels and pathological staining. The mechanisms underlying PTH's hepatoprotective effects were investigated in nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) knock-out (NLRP3^-/-), over expression NLRP3 (oe-NLRP3) mice, and wild-type mice with the injection of autophagy inhibitor (3-methyladenine, 3-MA).

RESULTS

APAP-exposed mice resulted in evident liver injury which was evidenced by hepatic necrosis and elevated levels of AST and ALT in the wild-type C57BL/6 mice. PTH dose-dependently reduced ALT, AST and upregulated autophagy activity. In addition, PTH significantly reduced elevated levels of proinflammatory cytokines and NLRP3 inflammasome. The liver protective effect of PTH (300 mg/kg) was still obvious in the oe-NLRP3 mice, however, it became insignificant in the NLRP3^-/- mice. When PTH (300 mg/kg) was co-treated with 3-MA to the wild-type C57BL/6 mice, the NLRP3 inhibition were reversed when autophagy was blocked.

CONCLUSION

PTH exerted a beneficial effect in protecting liver against APAP-induced liver injury. The underlying molecular mechanism was associated with the NLRP3 inflammasome inhibition which was likely driven by the upregulated autophagy activity. Our study underpins the traditional use of PTH in protecting liver through its anti-inflammatory action.

Organ dysfunction, injury, and failure in cardiogenic shock

BACKGROUND

Cardiogenic shock (CS) is caused by primary cardiac dysfunction and induced by various and heterogeneous diseases (e.g., acute impairment of cardiac performance, or acute or chronic impairment of cardiac performance).

MAIN BODY

Although a low cardiac index is a common finding in patients with CS, the ventricular preload, pulmonary capillary wedge pressure, central venous pressure, and systemic vascular resistance might vary between patients. Organ dysfunction has traditionally been attributed to the hypoperfusion of the organ due to either progressive impairment of the cardiac output or intravascular volume depletion secondary to CS. However, research attention has recently shifted from this cardiac output ("forward failure") to venous congestion ("backward failure") as the most important hemodynamic determinant. Both hypoperfusion and/or venous congestion by CS could lead to injury, impairment, and failure of target organs (i.e., heart, lungs, kidney, liver, intestines, brain); these effects are associated with an increased mortality rate. Treatment strategies for the prevention, reduction, and reversal of organ injury are warranted to improve morbidity in these patients. The present review summarizes recent data regarding organ dysfunction, injury, and failure.

CONCLUSIONS

Early identification and treatment of organ dysfunction, along with hemodynamic stabilization, are key components of the management of patients with CS.

The molecular mechanisms of acetaminophen-induced hepatotoxicity and its potential therapeutic targets

Acetaminophen (APAP), a widely used antipyretic and analgesic drug in clinics, is relatively safe at therapeutic doses; however, APAP overdose may lead to fatal acute liver injury. Currently, N-acetylcysteine (NAC) is clinically used as the main antidote for APAP poisoning, but its therapeutic effect remains limited owing to rapid disease progression and the general diagnosis of advanced poisoning. As is well known, APAP-induced hepatotoxicity (AIH) is mainly caused by the toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI), and the toxic mechanisms of AIH are complicated. Several cellular processes are involved in the pathogenesis of AIH, including liver metabolism, mitochondrial oxidative stress and dysfunction, sterile inflammation, endoplasmic reticulum stress, autophagy, and microcirculation dysfunction. Mitochondrial oxidative stress and dysfunction are the major cellular events associated with APAP-induced liver injury. Many biomolecules involved in these biological processes are potential therapeutic targets for AIH. Therefore, there is an urgent need to comprehensively clarify the molecular mechanisms underlying AIH and to explore novel therapeutic strategies. This review summarizes the various cellular events involved in AIH and discusses their potential therapeutic targets, with the aim of providing new ideas for the treatment of AIH.

3,4-dihydroxyphenylethyl alcohol glycoside reduces acetaminophen-induced acute liver failure in mice by inhibiting hepatocyte ferroptosis and pyroptosis

APAP is one of the most commonly used antipyretic and pain medications, but excessive use can cause liver toxicity and damage. 3,4-dihydroxyphenylethyl alcohol glycoside (DAG) is a component isolated from Sargentodoxa cuneata known to have anti-apoptotic, anti-oxidation and anti-inflammatory effects. However, the effects of DAG on acute liver failure (ALF) are largely unknown. The purpose of this study is to study the protective effects and mechanism of DAG on APAP-induced ALF in mice. We established an ALF model in adult male pathogen-free C57BL/6 mice treated with APAP (300 mg/kg) by intraperitoneal injection and resolved by 24 h. Hematoxylin and eosin (HE) staining was used to evaluate the pathological changes in mouse liver tissue. The infiltration of neutrophils in liver tissue and reactive oxygen species (ROS) in AML12 cells were analyzed by flow cytometry. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutathione (GSH), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD) were analyzed using relevant kits. Our results show that DAG reduced APAP-induced serum ALT and AST levels, histopathological changes, liver neutrophil infiltration and proinflammatory cytokines production, also attenuated the accumulation of MDA and the exhaustion of GSH, CAT and SOD. In vitro experiment indicated that DAG dose-dependently inhibited APAP-induced the levels of pro-inflammatory factors (IL-1β and IL18), and reactive oxygen species (ROS) and preventing GSH depletion in mouse AML12 hepatocytes. More interestingly, DAG inhibited the expression of ERK, HO-1, NLRP3, Caspase1 (p20) and Gasdermin-D and upregulated the expression of GPX4 in liver tissues and AML12hepatocytes. Therefore, our results indicate that DAG may act as a potential agent to treat ALF induced by APAP by inhibiting hepatocyte ferroptosis and pyroptosis.

Mesenchymal Stem Cell Therapy for Acetaminophen-Related Liver Injury: A Systematic Review and Meta-Analysis of Experimental Studies in Vivo

OBJECTIVE

The efficacy of mesenchymal stem cell (MSC) therapy in acetaminophen-induced liver injury has been investigated in animal experiments, but individual studies with a small sample size cannot be used to draw a clear conclusion. Therefore, we conducted a systematic review and meta-analysis of preclinical studies to explore the potential of using MSCs in acetaminophen-induced liver injury.

METHODS

Eight databases were searched for studies reporting the effects of MSCs on acetaminophen hepatoxicity. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used. SYRCLE's risk of bias tool for animal studies was applied to assess the methodological quality. A meta-analysis was performed by using RevMan 5.4 and STATA/SE 16.0 software.

RESULTS

Eleven studies involving 159 animals were included according to PRISMA statement guidelines. Significant associations were found for MSCs with the levels of alanine transaminase (ALT) (standardized mean difference (SMD) - 2.58, p < 0.0001), aspartate aminotransferase (AST) (SMD - 1.75, p = 0.001), glutathione (GSH) (SMD 3.7, p < 0.0001), superoxide dismutase (SOD) (SMD 1.86, p = 0.022), interleukin 10 (IL-10) (SMD 5.14, p = 0.0002) and tumor necrosis factor-α (TNF-α) (SMD - 4.48, p = 0.011) compared with those in the control group. The subgroup analysis showed that the tissue source of MSCs significantly affected the therapeutic efficacy (p < 0.05).

CONCLUSION

Our meta-analysis results demonstrate that MSCs could be a potential treatment for acetaminophen-related liver injury.

Enhancement of TEX264-Mediated ER-Phagy Contributes to the Therapeutic Effect of Glycycoumarin against APA Hepatotoxicity in Mice

Acetaminophen (APA)-induced hepatotoxicity is coupled with the activation of autophagy. We sought to determine whether selective autophagy of the endoplasmic reticulum (ER), termed ER-phagy, is involved in APA hepatotoxicity and to explore its potential as a therapeutic target for APA-induced liver injury (AILI). APA (300 or 600 mg/kg) was administered to male C57BL/6N mice, with and without rapamycin, glycycoumarin (GCM) and N-acetylcysteine (NAC). The results demonstrated that ER-phagy accompanied with ER stress was activated after APA overdose. The dynamic changes of LC3 and TEX264 revealed that ER-phagy was induced as early as 6 h and peaked at 24 h following the APA injection. A delayed treatment with GCM, but not rapamycin, considerably attenuated a liver injury and, consequently, reduced its mortality. This is probably due to the inhibition of ER stress and the acceleration of liver regeneration via enhanced ER-phagy. Unlike the impaired hepatocyte proliferation and more severe liver injury in mice that received prolonged treatment with NAC, liver recovery is facilitated by repeated treatment with GCM. These findings suggest that TEX264-mediated ER-phagy is a compensatory mechanism against ER stress provoked by an APA overdose. A delayed and prolonged treatment with GCM enhances ER-phagy, thus serving as a potential therapeutic approach for patients presenting at the late stage of AILI.

Can granulocyte colony stimulating factor (G-CSF) ameliorate acetaminophen-induced hepatotoxicity?

Acetaminophen (APAP) is often used as an antipyretic and analgesic agent. Overdose hepatotoxicity, which often results in liver cell failure and liver transplantation, is a severe complication of APAP usage. To save the liver and save lives from acute liver damage caused by APAP, the search for new strategies for liver defense is important. Wistar rats have been used for the induction of APAP hepatotoxicity. Elevated levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) were evaluated for liver toxicity. In addition, the levels of hepatic tissue oxidative markers such as malondialdehyde (MDA), nitric oxide (NO) increased while glutathione (GSH) was depleted and catalase (CAT) activity was curtailed. The biochemical findings were consistent with the changes in histology that suggested liver damage and inflammation. Treated rats with N-acetylcysteine (N-AC) and granulocyte colony stimulating factor (G-CSF) showed a decrease in serum levels of ALT, AST and LDH, while the level of ALP in the G-CSF group was still high. After administration of APAP, treatment with N-AC or G-CSF substantially reduced the level of MDA and NO while maintaining the GSH content and CAT activity. Treatment with N-AC and G-CSF after administration of APAP has also attenuated inflammation and hepatocytes necrosis. The results of this study showed that G-CSF could be viewed as an alternative hepatoprotective agent against APAP-induced acute liver injury compared to N-AC.

Pain Management in Patients with Serious Illness

Managing pain in patients with serious illness can be complex. However, pain is often a prominent symptom in patients with malignant and nonmalignant serious illness and providers have to be adept at balancing effective pain management and safety. Clinicians should start with a standard pain assessment that lays important groundwork for developing a tailored multimodal approach to pain management. It is important to identify physical causes of pain and also existential causes. Opioids are not always appropriate but are still an important tool for managing pain. Basic opioid management and safe practices are essential when managing this population.

Herbal Therapy for the Treatment of Acetaminophen-Associated Liver Injury: Recent Advances and Future Perspectives

Acetaminophen (APAP) overdose is the leading cause of drug-induced liver injury worldwide, and mitochondrial oxidative stress is considered the major event responsible for APAP-associated liver injury (ALI). Despite the identification of N-acetyl cysteine, a reactive oxygen species scavenger that is regarded as an effective clinical treatment, therapeutic effectiveness remains limited due to rapid disease progression and diagnosis at a late phase, which leads to the need to explore various therapeutic approaches. Since the early 1990s, a number of natural products and herbs have been found to have hepatoprotective effects against APAP-induced hepatotoxicity in terms of acute liver failure prevention and therapeutic amelioration of ALI. In this review, we summarize the hepatoprotective effects and mechanisms of medicinal plants, including herbs and fruit extracts, along with future perspectives that may provide guidance to improve the current status of herbal therapy against ALI.

Acute Liver Failure Induces Glial Reactivity, Oxidative Stress and Impairs Brain Energy Metabolism in Rats

Acute liver failure (ALF) implies a severe and rapid liver dysfunction that leads to impaired liver metabolism and hepatic encephalopathy (HE). Recent studies have suggested that several brain alterations such as astrocytic dysfunction and energy metabolism impairment may synergistically interact, playing a role in the development of HE. The purpose of the present study is to investigate early alterations in redox status, energy metabolism and astrocytic reactivity of rats submitted to ALF. Adult male Wistar rats were submitted either to subtotal hepatectomy (92% of liver mass) or sham operation to induce ALF. Twenty-four hours after the surgery, animals with ALF presented higher plasmatic levels of ammonia, lactate, ALT and AST and lower levels of glucose than the animals in the sham group. Animals with ALF presented several astrocytic morphological alterations indicating astrocytic reactivity. The ALF group also presented higher mitochondrial oxygen consumption, higher enzymatic activity and higher ATP levels in the brain (frontoparietal cortex). Moreover, ALF induced an increase in glutamate oxidation concomitant with a decrease in glucose and lactate oxidation. The increase in brain energy metabolism caused by astrocytic reactivity resulted in augmented levels of reactive oxygen species (ROS) and Poly [ADP-ribose] polymerase 1 (PARP1) and a decreased activity of the enzymes superoxide dismutase and glutathione peroxidase (GSH-Px). These findings suggest that in the early stages of ALF the brain presents a hypermetabolic state, oxidative stress and astrocytic reactivity, which could be in part sustained by an increase in mitochondrial oxidation of glutamate.

Role of autophagy in alcohol and drug-induced liver injury

Alcohol-related liver disease (ALD) and drug-induced liver injury (DILI) are common causes of severe liver disease, and successful treatments are lacking. Autophagy plays a protective role in both ALD and DILI by selectively removing damaged mitochondria (mitophagy), lipid droplets (lipophagy), protein aggregates and adducts in hepatocytes. Autophagy also protects against ALD by degrading interferon regulatory factor 1 (IRF1) and damaged mitochondria in hepatic macrophages. Specifically, we will discuss selective autophagy for removal of damaged mitochondria and lipid droplets in hepatocytes and autophagy-mediated degradation of IRF1 in hepatic macrophages as protective mechanisms against alcohol-induced liver injury and steatosis. In addition, selective autophagy for removal of damaged mitochondria and protein adducts for protection against DILI is discussed in this review. Development of new therapeutics for ALD and DILI is greatly needed, and selective autophagy pathways may provide promising targets. Drug and alcohol effects on autophagy regulation as well as protective mechanisms of autophagy against DILI and ALD are highlighted in this review.

The MAP2K4/JNK/c-Jun Signaling Pathway Plays A Key Role In Dexmedetomidine Protection Against Acetaminophen-Induced Liver Toxicity

Purpose

Dexmedetomidine [DEX; (S)-4-[1-(2,3-dimethylphenyl)ethyl]-3H-imidazole] is a selective α₂-adrenergic receptor (α₂-AR) agonist that attenuates the liver damage associated with local or systemic inflammation. However, it remains unclear whether DEX has protective effects against acetaminophen (Paracetamol, PARA)-induced liver toxicity (PILT).

Methods

PILT mice were established by intraperitoneal administration of a hepatotoxic dose of acetaminophen (300 mg/kg). Thirty minutes later, the mice were treated with DEX at a concentration of 0, 5, 25, or 50 μg/kg. Blood and liver samples were obtained for further analysis.

Results

DEX treatment significantly attenuated PILT in mice, with the strongest beneficial effects at a dose of 25 μg/kg. The levels of hepatic cytokines, tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), in addition to myeloperoxidase (MPO) activity, were significantly decreased following DEX treatment. Moreover, DEX treatment reduced macrophage recruitment around the area of hepatotoxicity and the expression levels of hepatic phosphorylated mitogen-activated protein kinase kinase 4 (MAP2K4), c-jun N-terminal kinase (JNK), and c-Jun expression induced by acetaminophen overdose.

Conclusion

The data suggest that DEX likely downregulates the JNK signaling pathway and its downstream effectors to promote its hepatoprotective effect, providing a clinical application of DEX for the attenuation of PILT.

Acute Liver Failure: From Textbook to Emergency Room and Intensive Care Unit With Concomitant Established and Modern Novel Therapies

Acute liver failure is a rare hepatic emergent situation that affects primarily young people and has often a catastrophic or even fatal outcome. Definition of acute liver failure has not reached a universal consensus and the interval between the appearance of jaundice and hepatic encephalopathy for the establishment of the acute failure is a matter of debate. Among the wide variety of causes, acetaminophen intoxication in western societies and viral hepatitis in the developing countries rank at the top of the etiology list. Identification of the clinical appearance and initial management for the stabilization of the patient are of vital significance. Further advanced therapies, that require intensive care unit, should be offered. The hallmark of treatment for selected patients can be orthotopic liver transplantation. Apart from well-established treatments, novel therapies like hepatocyte or stem cell transplantation, additional new therapeutic strategies targeting acetaminophen intoxication and/or hepatic encephalopathy are mainly experimental, and some of them do not belong, yet, to clinical practice. For clinicians, it is substantial to have the alertness to timely identify the patient and transfer them to a specialized center, where more treatment opportunities are available.

Infectious Complications in Patients Who Received High-Volume Plasma Exchange Prior to Liver Transplant: A Case Report

Acute liver failure is a rare but life-threatening medical emergency. Despite advancements in medical management, mortality rates of acute liver failure remain high. Currently, liver transplant is the only definitive therapeutic option available. High-volume plasma exchange has been shown to increase transplant-free survival in patients with acute liver failure before liver transplant. However, the occurrence of infectious complications in patients who receive this treatment has not been well studied. We report 2 cases of severe opportunistic infections occurring within 30 days of transplant in patients who underwent high-volume plasma exchange before liver transplant.

Outcome of Acetaminophen-Induced Acute Liver Failure Managed Without Intracranial Pressure Monitoring or Transplantation

Acetaminophen-induced acute liver failure (ALF) may require emergency liver transplantation (LT) in the presence of specific criteria, and its management may also include intracranial pressure (ICP) monitoring in selected patients at high risk of cerebral edema. We aimed to test the hypothesis that management of such patients without ICP monitoring or LT would yield outcomes similar to those reported with conventional management. We interrogated a database of all patients treated in an intensive care unit for acetaminophen-induced ALF between November 2010 and October 2016 and obtained relevant information from electronic medical records. We studied 64 patients (58 females) with a median age of 38 years. Such patients had a high prevalence of depression, substance abuse, or other psychiatric disorders and had ingested a median acetaminophen dose of 25 g. No patient received ICP monitoring or LT. Overall, 51 (79.7%) patients survived. Of the 42 patients who met King's College Hospital (KCH) criteria, 29 (69.0%) survived without transplantation. There were 45 patients who developed severe hepatic encephalopathy, and 32 (71.1%) of these survived. Finally, compared with the KCH criteria, the current UK Registration Criteria for Super-Urgent Liver Transplantation (UKRC) for super-urgent LT had better sensitivity (92.3%) and specificity (80.4%) for hospital mortality. In conclusion, in a center applying a no ICP monitoring and no LT approach to the management of acetaminophen-induced ALF, during a 6-year period, overall survival was 79.7%, and for patients fulfilling KCH criteria, it was 69.0%, which were both higher than for equivalent patients treated with conventional management as reported in the literature. Finally, the current UKRC may be a better predictor of hospital mortality in this patient population.

A case report of full recovery from severe cerebral edema secondary to acetaminophen-induced hepatotoxicity in a 13 year old girl

Background

Acetaminophen is a common cause of acute liver failure in pediatrics. Cerebral edema is a significant complication of acute hepatic failure and is associated with increased mortality.

Case presentation

We present a case of a 13 -year old girl with severe cerebral edema secondary to acetaminophen toxicity and hepatic failure. Her poor neurological status precluded her from liver transplantation and withdrawal of life sustaining treatment was recommended. However, with supportive care, she remarkably made a full recovery.

Conclusions

This case highlights the difficulties surrounding prognostication in pediatric patients with cerebral edema from acute liver failure secondary to acetaminophen toxicity.

Mechanisms of acetaminophen-induced liver injury and its implications for therapeutic interventions

Acetaminophen (APAP) overdose is the leading cause of drug-induced acute liver failure in many developed countries. Mitochondrial oxidative stress is considered to be the predominant cellular event in APAP-induced liver injury. Accordingly, N-acetyl cysteine, a known scavenger of reactive oxygen species (ROS), is recommended as an effective clinical antidote against APAP-induced acute liver injury (AILI) when it is given at an early phase; however, the narrow therapeutic window limits its use. Hence, the development of novel therapeutic approaches that can offer broadly protective effects against AILI is clearly needed. To this end, it is necessary to better understand the mechanisms of APAP hepatotoxicity. Up to now, in addition to mitochondrial oxidative stress, many other cellular processes, including phase I/phase II metabolism, endoplasmic reticulum stress, autophagy, sterile inflammation, microcirculatory dysfunction, and liver regeneration, have been identified to be involved in the pathogenesis of AILI, providing new targets for developing more effective therapeutic interventions against APAP-induced liver injury. In this review, we summarize intracellular and extracellular events involved in APAP hepatotoxicity, along with emphatic discussions on the possible therapeutic approaches targeting these different cellular events.

Elevated cardiac troponin T in cirrhotic patients with emergency care admissions: Associations with mortality

BACKGROUND AND AIM

Mortality of cirrhotic patients after emergency care admission is high, and prognostic factors can help in prioritizing patients. The aim of our study was to assess the association between levels of cardiac troponin T (cTnT) and 1-year mortality in patients with liver cirrhosis without known cardiac disease, who were admitted to the emergency department (ED).

METHODS

All patients with cirrhosis presented to the ED from October 2009 until August 2015 who had an initial cTnT value measured with the first lab panel were retrospectively analyzed with a follow-up of 365 days.

RESULTS

Of a total of 237 cirrhotic ED patients, cTnT measurements were available for 87 (63% men, mean age 58.9 ± 11.0 years, and median Model for End-stage Liver Disease score was 15 [25th-75th percentile: 10-19]). Chronic Liver Failure Consortium acute-on-chronic liver failure (CLIF-C-ACLF) score was 33. Forty-three patients (49%) had cTnT values above the normal range (14 ng/L), of which 19 (22%) had values over 30 ng/L. Two patients were lost to follow-up. In multivariable analysis, both CLIF-C-ACLF (hazard ratio 1.072 per point increase; 95% confidence interval 1.029-1.117; P < 0.001) and cTnT (hazard ratio 1.014 per ng/L increase; 95% confidence interval 1.004-1.024; P = 0.008) emerged as independently associated with mortality.

CONCLUSIONS

A large proportion of cirrhotic patients in the ED have elevated levels of cTnT even if there is no evidence of cardiac disease. Elevated cTnT is associated with increased mortality during 1 year after correcting for Model for End-stage Liver Disease and CLIF-C-ACLF scores.

Bacterial Infections

Bacterial infections are the most significant infectious source of morbidity and mortality in cirrhotic patients. Bacteria infections result is both acute decompensation in chronic liver disease and mortality in patients with decompensated cirrhosis. Spontaneous bacterial peritonitis (SBP), bacteremia, pneumonia, urinary tract infections (UTI) and skin and soft tissue infection (SSTI) are the most significant sources of infection in cirrhosis. Bacterial infections can precipitate renal failure and worsening hepatic encephalopathy, and patients with sepsis and liver disease have higher rates of acute respiratory distress syndrome (ARDS) and coagulopathy.

Stellate Cells Orchestrate Concanavalin A-Induced Acute Liver Damage

Concanavalin A (ConA) causes immune cell-mediated liver damage, but the contribution of resident nonparenchymal cells (NPCs) is also evident. Hepatic stellate cells (HSCs) induce hepatic inflammation and immunological reactions; we therefore investigated their role in ConA-induced liver injury. ConA was administered i.v. to control or HSC-depleted mice; hepatic histopathology and cytokines/chemokines were determined after 6 hours. In vitro, effects of ConA-conditioned HSC medium on hepatocytes were determined. ConA induced inflammation, sinusoidal congestion, and extensive midzonal hepatocyte death in control mice, which were strongly minimized in HSC-depleted mice. CD4 and natural killer T cells and neutrophils were markedly reduced in ConA-treated HSC-depleted mice compared with control mice. The increase in cytokines/chemokines of hepatic injury was much higher in ConA-treated control mice than in HSC-depleted mice. ConA-treated HSCs showed increased expression of interferon-β, tumor necrosis factor-α, and CXCL1, induced oxidative stress in hepatocytes, and caused hepatocyte apoptosis. ConA induced nuclear translocation of interferon-regulatory factor-1 (IRF1) in hepatocytes in vivo, and ConA/HSC induced a similar effect in cultured hepatocytes. IRF1-knockout mice were resistant to ConA-induced liver damage, and anti-interferon β antibody mitigated ConA/HSC-induced injury. In HSC-NPC co-culture, ConA-induced expression of inflammatory cytokines/chemokines was significantly augmented compared with NPCs alone. HSCs play an essential role in ConA-induced liver injury directly via the interferon-β/IRF1 axis, and by modulating properties of NPCs.

Organ dysfunction, injury and failure in acute heart failure: from pathophysiology to diagnosis and management. A review on behalf of the Acute Heart Failure Committee of the Heart Failure Association (HFA) of the European Society of Cardiology (ESC)

Organ injury and impairment are commonly observed in patients with acute heart failure (AHF), and congestion is an essential pathophysiological mechanism of impaired organ function. Congestion is the predominant clinical profile in most patients with AHF; a smaller proportion presents with peripheral hypoperfusion or cardiogenic shock. Hypoperfusion further deteriorates organ function. The injury and dysfunction of target organs (i.e. heart, lungs, kidneys, liver, intestine, brain) in the setting of AHF are associated with increased risk for mortality. Improvement in organ function after decongestive therapies has been associated with a lower risk for post-discharge mortality. Thus, the prevention and correction of organ dysfunction represent a therapeutic target of interest in AHF and should be evaluated in clinical trials. Treatment strategies that specifically prevent, reduce or reverse organ dysfunction remain to be identified and evaluated to determine if such interventions impact mortality, morbidity and patient-centred outcomes. This paper reflects current understanding among experts of the presentation and management of organ impairment in AHF and suggests priorities for future research to advance the field.

[Metamizole (dipyrone): mode of action, drug-drug interactions, and risk of agranulocytosis]

Metamizole (dipyrone) is a nonsteroidal compound with strong analgesic as well as antipyretic and spasmolytic properties. Based on a small number of cases of agranulocytosis, metamizole was withdrawn from the market in some countries. Other countries restricted its use. This paper discusses the safety aspects of metamizole and compares it with other compounds used for similar indications.

Hepatoprotective Effect of Opuntia robusta and Opuntia streptacantha Fruits against Acetaminophen-Induced Acute Liver Damage

Acetaminophen (APAP)-induced acute liver failure (ALF) is a serious health problem in developed countries. N-acetyl-L-cysteine (NAC), the current therapy for APAP-induced ALF, is not always effective, and liver transplantation is often needed. Opuntia spp. fruits are an important source of nutrients and contain high levels of bioactive compounds, including antioxidants. The aim of this study was to evaluate the hepatoprotective effect of Opuntia robusta and Opuntia streptacantha extracts against APAP-induced ALF. In addition, we analyzed the antioxidant activities of these extracts. Fruit extracts (800mg/kg/day, orally) were given prophylactically to male Wistar rats before intoxication with APAP (500 mg/kg, intraperitoneally). Rat hepatocyte cultures were exposed to 20mmol/LAPAP, and necrosis was assessed by LDH leakage. Opuntia robusta had significantly higher levels of antioxidants than Opuntia streptacantha. Both extracts significantly attenuated APAP-induced injury markers AST, ALT and ALP and improved liver histology. The Opuntia extracts reversed APAP-induced depletion of liver GSH and glycogen stores. In cultured hepatocytes, Opuntia extracts significantly reduced leakage of LDH and cell necrosis, both prophylactically and therapeutically. Both extracts appeared to be superior to NAC when used therapeutically. We conclude that Opuntia extracts are hepatoprotective and can be used as a nutraceutical to prevent ALF.

Circulating full-length cytokeratin 18 for predicting prognosis of hepatitis B virus-related acute-on-chronic liver failure patients with lamivudine treatment

AIM

The predictive value of circulating full-length cytokeratin 18 (M65) on prognosis of hepatitis B virus-related liver failure is still not well investigated. The aim of this study was to reveal the association between serum M65 levels and outcomes of hepatitis B virus-related acute-on-chronic liver failure, and to further clarify clinical significance of M65 in lamivudine treatment.

METHODS

Ninety-six patients with hepatitis B virus-related acute-on-chronic liver failure were recruited between January 2011 and December 2013, and 52 of them received lamivudine treatment. Blood were obtained from participants at admission, and M65 were determined by enzyme-linked immunosorbent assay. Other necessary data were collected from medical records.

RESULTS

The liver failure patients were divided into high and low level groups according to the serum M65 levels. After 24-week follow up, survival incidences were significantly higher in the low level group than that in the high level group (odds ratio [OR] = 0.3, 95% confidence interval = 0.1-0.7). In addition, the survival incidences and albumin levels improved in the patients with lamivudine treatment compared with the patients without lamivudine treatment in the low level group (OR = 5.4, 95% CI = 1.1-26.0 and OR = 4.2, 95% CI = 1.3-13.2). A similar improvement was not observed in the high level group.

CONCLUSION

The study suggested that the circulating M65 may serve as a relatively independent prognostic parameter for liver failure. If prospectively validated in further studies, M65 measurement may also be a useful method for optimizing antiviral therapy.

Adverse drug reactions and organ damage: The liver

Drug-induced liver injury (DILI) is among the most challenging acute or chronic liver conditions to be handled by physicians. Despite its low incidence in the general population, DILI is a frequent cause of acute liver failure. As such, the possibility of DILI should be considered in all patients who present with acute liver damage, independent of any known pre-existing liver disease. DILI can be classified as intrinsic/dose-dependent (e.g., acetaminophen toxicity) or idiosyncratic/dose-independent, with the latter form being relatively uncommon. Amoxicillin-clavulanate is the antimicrobial that is most frequently associated with idiosyncratic DILI. Large, ongoing, prospective studies in western countries have reported other drugs associated with DILI, including nonsteroidal anti-inflammatory drugs, statins, and herbal and dietary supplements. An important safety issue, DILI is one of the most frequently cited reasons for cessation of drug development during or after preclinical studies and for withdrawal of a drug from the market. This review summarizes the epidemiology, risk factors, commonly implicated drugs, clinical features, and diagnosis of DILI, with the aim of aiding physicians in the management of this debated problem. Old and new biomarkers for DILI and pharmacogenetic studies are also described.

Mycetismus: a review

Although rare, death from amanitin exposure poses a significant health risk and a diagnostic challenge to the clinician due to its rarity. This is one of the few conditions to be voluntarily reported by healthcare professionals. No antidote exists for this poisoning and, perhaps due to its rarity or lack of attention, the United States has lagged behind Europe for almost three decades in treatment, diagnostics and experimentation. This regrettable fact warrants the formation of a centralized agency for education, the advancement of research and the collection of data, to provide better treatment for the population.

Circulating levels of soluble receptor for advanced glycation end products and ligands of the receptor for advanced glycation end products in patients with acute liver failure

Animal studies suggest that receptor for advanced glycation end products (RAGE)-dependent mechanisms contribute to acetaminophen-induced liver damage. We examined whether circulating levels of soluble receptor for advanced glycation end products (sRAGE) or RAGE ligands, including extracellular newly identified receptor for advanced glycation end products binding protein (EN-RAGE), high-mobility group box 1 (HMGB1), and Nε-(Carboxymethyl)lysine adducts (CML), could aid in prognostication after an acetaminophen overdose. Sixty well-characterized acetaminophen-related acute liver failure (ALF) patients (30 spontaneous survivors and 30 patients who underwent transplantation and/or died) who were enrolled in the National Institutes of Health-sponsored Acute Liver Failure Study Group, were matched by age, met standard criteria for encephalopathy, and had an international normalized ratio > 1.5 were retrospectively studied. HMGB1, EN-RAGE, CML, and sRAGE were detected by enzyme-linked immunosorbent assay methods in sera from ALF patients and 30 healthy controls. Levels of sRAGE, EN-RAGE, and HMGB1 (but not CML) were significantly greater (P < 0.001) in ALF patients versus normal controls. The levels of sRAGE, HMGB1, and EN-RAGE were significantly higher (P = 0.03, P < 0.01, and P = 0.03) in patients with a systemic inflammatory response syndrome (SIRS) score > 2 versus patients with a SIRS score ≤ 2. Nevertheless, only sRAGE levels were significantly higher in patients who underwent transplantation and/or died versus spontaneous survivors (P < 0.001), and they were positively associated with conventional markers of liver disease severity. Multivariate logistic regression identified an encephalopathy grade > 2 as an independent predictor of an adverse outcome on admission (odds ratio, 13; 95% confidence interval, 2.3-73; P < 0.001). The RAGE-ligand axis may interfere with liver regeneration and should be a promising objective for further research.

Acute liver failure in dogs and cats

OBJECTIVE

To define acute liver failure (ALF), review the human and veterinary literature, and discuss the etiologies and current concepts in diagnostic and treatment options for ALF in veterinary and human medicine.

ETIOLOGY

In veterinary medicine ALF is most commonly caused by hepatotoxin exposure, infectious agents, inflammatory diseases, trauma, and hypoxic injury.

DIAGNOSIS

A patient may be deemed to be in ALF when there is a progression of acute liver injury with no known previous hepatic disease, the development of hepatic encephalopathy of any grade that occurs within 8 weeks after the onset of hyperbilirubinemia (defined as plasma bilirubin >50 μM/L [>2.9 mg/dL]), and the presence of a coagulopathy. Diagnostic testing to more specifically characterize liver dysfunction or pathology is usually required.

THERAPY

Supportive care to aid the failing liver and compensate for the lost functions of the liver remains the cornerstone of care of patients with ALF. Advanced therapeutic options such as extracorporeal liver assist devices and transplantation are currently available in human medicine.

PROGNOSIS

The prognosis for ALF depends upon the etiology, the degree of liver damage, and the response to therapy. In veterinary medicine, the prognosis is generally poor.

Acetaminophen hepatotoxicity: an updated review

As the most common cause of acute liver failure (ALF) in the USA and UK, acetaminophen-induced hepatotoxicity remains a significant public health concern and common indication for emergent liver transplantation. This problem is largely attributable to acetaminophen combination products frequently prescribed by physicians and other healthcare professionals, with unintentional and chronic overdose accounting for over 50 % of cases of acetaminophen-related ALF. Treatment with N-acetylcysteine can effectively reduce progression to ALF if given early after an acute overdose; however, liver transplantation is the only routinely used life-saving therapy once ALF has developed. With the rapid course of acetaminophen-related ALF and limited supply of donor livers, early and accurate diagnosis of patients that will require transplantation for survival is crucial. Efforts in developing novel treatments for acetaminophen-induced ALF are directed toward bridging patients to recovery. These include auxiliary, artificial, and bioartificial support systems. This review outlines the most recent developments in diagnosis and management of acetaminophen-induced ALF.

Scoring systems for 6-month mortality in critically ill cirrhotic patients: a prospective analysis of chronic liver failure - sequential organ failure assessment score (CLIF-SOFA)

BACKGROUND

Cirrhotic patients admitted to intensive care units (ICUs) have high mortality rates. The Chronic Liver Failure-Sequential Organ Failure Assessment (CLIF-SOFA) score, a modified Sequential Organ Failure Assessment (SOFA) score, is a newly developed scoring system exclusively for patients with end-stage liver disease.

AIM

To externally validate the efficacy of the CLIF-SOFA score and evaluate other scoring systems for 6-month mortality in critically ill cirrhotic patients.

METHODS

This study prospectively recorded and analysed the data for 30 demographical parameters and some clinical characteristic variables on day 1 of 250 cirrhotic patients admitted to a 10-bed specialised hepatogastroenterology ICU in a 2000-bed tertiary care referral hospital during the period from September 2010 to August 2013.

RESULTS

The overall in-hospital and 6-month mortality rate were 58.8% (147/250) and 78.0% (195/250), respectively. Liver diseases were mostly attributed to hepatitis B virus infection (32%). Multiple Cox logistic regression hazard analysis revealed that Glasgow coma scale, both the CLIF-SOFA and Acute Physiology and Chronic Health Evaluation III (ACPACHE III) scores determined on the first day of ICU admission were independent predictors of 6-month mortality. Analysis of the area under the receiver operating characteristic curve revealed that the CLIF-SOFA score had the best discriminatory power (0.900 ± 0.020). Moreover, the cumulative 6-month survival rates differed significantly for patients with a CLIF-SOFA score ≤11 and those with a CLIF-SOFA score >11 on the ICU admission day.

CONCLUSION

Both CLIF-SOFA and APACHE III scores are excellent prognosis evaluation tools for critically ill cirrhotic patients.

Clinical significance of miRNA changes in chronic liver diseases

MicroRNAs (miRNAs) are small molecules that regulate gene expression at the post-transcriptional level. MiRNAs could exhibit specific changes in many liver diseases, which reflects pathologic changes of hepatic tissue. To better understand the relationship between miRNAs and liver diseases, this review summarizes the roles of miRNAs in hepatitis, alcohol-induced liver injury, drug-induced liver injury and hepatocellular carcinoma. Investigation of miRNA changes in humans might not only help to elucidate the mechanism of chronic hepatitis B virus infection, but also provide new molecular markers for clinical diagnosis and evaluation of the curative effect of antiviral treatment. In addition, it might provide new ideas and methods for the diagnosis and treatment of alcoholic liver disease, drug-induced liver injury, fatty liver disease and hepatocellular carcinoma.

Circulating microRNA profiles in human patients with acetaminophen hepatotoxicity or ischemic hepatitis

We have identified, by quantitative real-time PCR, hundreds of miRNAs that are dramatically elevated in the plasma or serum of acetaminophen (APAP) overdose patients. Most of these circulating microRNAs decrease toward normal levels during treatment with N-acetyl cysteine (NAC). We identified a set of 11 miRNAs whose profiles and dynamics in the circulation during NAC treatment can discriminate APAP hepatotoxicity from ischemic hepatitis. The elevation of certain miRNAs can precede the dramatic rise in the standard biomarker, alanine aminotransferase (ALT), and these miRNAs also respond more rapidly than ALT to successful treatment. Our results suggest that miRNAs can serve as sensitive diagnostic and prognostic clinical tools for severe liver injury and could be useful for monitoring drug-induced liver injury during drug discovery.

Hepatitis E virus in patients with acute severe liver injury

AIM: To examine the incidence of hepatitis E (HepE) in individuals with acute liver injury severe enough to warrant treatment at a transplant unit.

METHODS: Hepatitis E virus (HEV) is an emerging pathogen in developed countries causing severe illness, particularly in immunocompromised patients or those with underlying chronic liver disease. HepE infection is often under diagnosed, as clinicians can be reluctant to test patients who have not travelled to regions traditionally considered hyperendemic for HepE. There are few data regarding the significance of HEV in patients with very severe acute liver injury in developed countries. Eighty patients with acute severe liver injury attending the Scottish Liver Transplant unit were tested for HEV and anti-HEV IgG and IgM. Severe acute liver injury was defined as a sudden deterioration in liver function confirmed by abnormal liver function tests and coagulopathy or presence of hepatic encephalopathy. Eighty percent of these patients were diagnosed with paracetomol overdose. No patients had a history of chronic or decompensated chronic liver disease at time of sampling. IgG positive samples were quantified against the World Health Organization anti-HEV IgG standard. Samples were screened for HEV viral RNA by quantitative reverse transcription polymerase chain reaction.

RESULTS: Four cases of hepatitis E were identified. Three of the four cases were only diagnosed on retrospective testing and were initially erroneously ascribed to drug-induced liver injury and decompensated chronic liver disease, with the cause of the decompensation uncertain. One case was caused by HEV genotype 1 in a traveller returning from Asia, the other three were autochthonous and diagnosed on retrospective testing. In two of these cases (where RNA was detected) HEV was found to be genotype 3, the most prevalent genotype in developed countries. Three patients survived, two of whom had been misdiagnosed as having drug induced liver injury. The fourth patient died from sepsis and liver failure precipitated as a result of hepatitis E infection and previously undiagnosed cirrhosis. Histopathology data to date is limited to mainly that seen for endemic HepE. All patients, with the exception of patient 1, demonstrated characteristics of HepE infection, as seen in previously described locally acquired cases.

CONCLUSION: In patients with acute severe liver injury, HEV testing should be part of the initial diagnostic investigation algorithm irrespective of suspected initial diagnosis, age or travel history.

Right-lobe living-donor liver transplantation in adult patients with acute liver failure

BACKGROUND

Right-lobe living-donor liver transplantation (RLDLT) is an excellent option to reduce donor shortages for adult patients with acute liver failure (ALF). The aim of this study was to evaluate the etiologies and outcomes of 30 consecutive adult patients who underwent emergency RLDLT for ALF.

METHODS

Between January 2007 and September 2011, we examined data from medical records of patients with ALF who underwent RLDLT.

RESULTS

Their mean age was 32.2 ± 13.05 years. The etiologies of ALF were acute hepatitis B (n = 11; 36.6%), hepatitis A (n = 4; 13.3%), drug intoxication (n = 4; 13.3%), pregnancy (n = 2; 6.7%), hepatitis B with pregnancy (n = 1; 3.3%), mushroom intoxication (n = 1; 3.3%), and unknown (n = 7; 23.3%). The mean hepatic coma grade (Model for End-Stage Liver Disease score) was 34.13 ± 8.72. The 43 (48.7%) postoperative complications were minor (grades I-II) and 44 (51.3%) were major (grades III-V). Reoperation was required in 14 of 30 (47%) recipients (grades IIIb-IVa). Deaths occurred owing to pulmonary (n = 2), cardiac (n = 1), septic (n = 2), or encephalopathic (n = 4) complications. The mean durations of intensive care unit stay and postoperative hospitalization were 3.2 ± 2.3 and 29.5 ± 23 days, respectively. The survival rate was 70%. The mean follow-up duration was 305 days (range, 1-1582).

CONCLUSION

Liver transplantation is potentially the only curative modality, markedly improving the prognosis of patients with ALF. The interval between ALF onset and death is short and crucial because of the rapid, progressive multiorgan failure. Thus, RLDLT should be considered to be a life-saving procedure for adult patients with ALF, requiring quicker access to a deceased-donor liver graft and a short ischemia time.

Acute liver failure in an obstetric patient: challenge of critical care for 1 patient with 2 subspecialty needs

Acute fatty liver of pregnancy is a rare and life-threatening disease associated with a defect in fatty acid metabolism in the fetus that causes liver disease in the mother. Prompt diagnosis and management are critical to the outcome of both the mother and the fetus and require involvement of several medical specialties, including hepatology, obstetrics, and, possibly, critical care. The included case study describes a woman with acute fatty liver of pregnancy decompensating to acute liver failure complicated by encephalopathy, cerebral edema, and intracranial hypertension. Subsequent management of these conditions, including the woman's progression to liver transplant, is provided.

Acute kidney injury in acute liver failure: a review

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

MicroRNAs in Liver Disease: Bench to Bedside

MicroRNAs (miRs) are small non-coding RNAs that negatively regulate gene expression by pairing with partially complementary target sequences in the 3'UTRs of mRNAs to promote degradation and/or block translation. Aberrant miR expression is associated with development of multiple diseases including hepatic diseases. The role of miRs in the regulation of gene expression and rapid progress in the field of microRNA research are resulting in momentum toward development of diagnostic markers and novel therapeutic strategies for human liver diseases. Recent studies provide clear evidence that miRs are abundant in the liver and modulate a diverse spectrum of biological functions, thereby supporting an association between alterations of miR homeostasis and pathological liver diseases. Here we review the role of miRs in liver as their physiological and pathological importance has been demonstrated in metabolism, immunity, viral hepatitis, oncogenesis, fatty liver diseases (alcoholic and non-alcoholic), drug-induced liver injury, fibrosis as well as acute liver failure.

Circulating microRNAs in exosomes indicate hepatocyte injury and inflammation in alcoholic, drug-induced, and inflammatory liver diseases

MicroRNAs are fine tuners of diverse biological responses and are expressed in various cell types of the liver. Here we hypothesized that circulating microRNAs (miRNAs) may serve as biomarkers of liver damage and inflammation. We studied miRNA-122, which is abundant in hepatocytes, and miR-155, -146a, and -125b, which regulate inflammation in immune cells in mouse models of alcoholic liver disease (ALD), drug (acetaminophen, APAP)-induced liver injury (DILI), and Toll-like receptor (TLR) 9+4 ligand-induced inflammatory cell-mediated liver damage. We found that serum/plasma miR-122 correlated with alanine aminotransferase (ALT) increases in the liver damage caused by alcohol, APAP, and TLR9 (CpG)+4 (LPS) ligands. MiR-155, a regulator of inflammation, was increased in serum/plasma in alcoholic and inflammatory liver injury. Alcohol failed to increase serum miR-122 in TLR4-deficient and p47phox-deficient mice that were protected from ALD. We found the most robust increase in plasma miR-122 in DILI and it correlated with the highest ALT levels. Consistent with the massive inflammatory cell infiltration in the liver, plasma miR-155 and miR-146a were significantly elevated after CpG+LPS administration. We show for the first time that, depending on the type of liver injury, circulating miRNAs are associated either with the exosome-rich or protein-rich compartments. In ALD and in inflammatory liver injury, serum/plasma miR-122 and miR-155 were predominantly associated with the exosome-rich fraction, whereas in DILI/APAP injury these miRNAs were present in the protein-rich fraction.

CONCLUSION

Our results suggest that circulating miRNAs may serve as biomarkers to differentiate between hepatocyte injury and inflammation and the exosome versus protein association of miRNAs may provide further specificity to mechanisms of liver pathology.

Plasma microRNA profiles distinguish lethal injury in acetaminophen toxicity: A research study

AIM: To investigate plasma microRNA (miRNA) profiles indicative of hepatotoxicity in the setting of lethal acetaminophen (APAP) toxicity in mice.

METHODS: Using plasma from APAP poisoned mice, either lethally (500 mg/kg) or sublethally (150 mg/kg) dosed, we screened commercially available murine microRNA libraries (SABiosciences, Qiagen Sciences, MD) to evaluate for unique miRNA profiles between these two dosing parameters.

RESULTS: We distinguished numerous, unique plasma miRNAs both up- and downregulated in lethally compared to sublethally dosed mice. Of note, many of the greatest up- and downregulated miRNAs, namely 574-5p, 466g, 466f-3p, 375, 29c, and 148a, have been shown to be associated with asthma in prior studies. Interestingly, a relationship between APAP and asthma has been previously well described in the literature, with an as yet unknown mechanism of pathology. There was a statistically significant increase in alanine aminotransferase levels in the lethal compared to sublethal APAP dosing groups at the 12 h time point (P < 0.001). There was 90% mortality in the lethally compared to sublethally dosed mice at the 48 h time point (P = 0.011).

CONCLUSION: We identified unique plasma miRNAs both up- and downregulated in APAP poisoning which are correlated to asthma development.

The sequential organ failure assessment (SOFA) score is an effective triage marker following staggered paracetamol (acetaminophen) overdose

BACKGROUND

The sequential organ failure assessment (SOFA) score is an effective triage marker following single time point paracetamol (acetaminophen) overdose, but has not been evaluated following staggered (multiple supratherapeutic doses over >8 h, resulting in cumulative dose of >4 g/day) overdoses.

AIM

To evaluate the prognostic accuracy of the SOFA score following staggered paracetamol overdose.

METHODS

Time-course analysis of 50 staggered paracetamol overdoses admitted to a tertiary liver centre. Individual timed laboratory samples were correlated with corresponding clinical parameters and the daily SOFA scores were calculated.

RESULTS

A total of 39/50 (78%) patients developed hepatic encephalopathy. The area under the SOFA receiver operator characteristic for death/liver transplantation was 87.4 (95% CI 73.2-95.7), 94.3 (95% CI 82.5-99.1), and 98.4 (95% CI 84.3-100.0) at 0, 24 and 48 h, respectively, postadmission. A SOFA score of <6 at tertiary care admission predicted survival with a sensitivity of 100.0% (95% CI 76.8-100.0) and specificity of 58.3% (95% CI 40.8-74.5), compared with 85.7% (95% CI 60.6-97.4) and 75.0% (95% CI 65.2-79.5) , respectively, for the modified Kings College criteria. Only 2/21 patients with an admission SOFA score <6 required renal replacement therapy or intracerebral pressure monitoring. SOFA significantly outperformed the Model for End-stage Liver Disease, but not APACHE II, at 0, 24-and 48-h following admission.

CONCLUSIONS

A SOFA score <6 at tertiary care admission following a staggered paracetamol overdose, is associated with a good prognosis. Both the SOFA and APACHE II scores could improve triage of high-risk staggered paracetamol overdose patients.