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.

Citrate pharmacokinetics in critically ill liver failure patients receiving CRRT.

Citrate has been proposed as anticoagulation of choice in continuous renal replacement therapy (CRRT). However, little is known about the pharmacokinetics (PK) and metabolism of citrate in liver failure patients who require CRRT with regional citrate anticoagulation (RCA). This prospective clinical PK study was conducted at King Chulalongkorn Memorial Hospital between July 2019 to April 2021, evaluating seven acute liver failure (ALF) and seven acute-on-chronic liver failure (ACLF) patients who received CRRT support utilizing RCA as an anticoagulant at a citrate dose of 3 mmol/L. For evaluation of the citrate PK, we delivered citrate for 120 min and then stopped for a further 120 min. Total body clearance of citrate was 152.5 ± 50.9 and 195.6 ± 174.3 mL/min in ALF and ACLF, respectively. The ionized calcium, ionized magnesium, and pH slightly decreased after starting citrate infusion and gradually increased to baseline after stopping citrate infusion. Two of the ACLF patients displayed citrate toxicity during citrate infusion, while, no ALF patient had citrate toxicity. In summary, citrate clearance was significantly decreased in critically ill ALF and ACLF patients receiving CRRT. Citrate use as an anticoagulation in these patients is of concern for the risk of citrate toxicity.

The Effect of TGF-ß1 Reduced Functionality on the Expression of Selected Synaptic Proteins and Electrophysiological Parameters: Implications of Changes Observed in Acute Hepatic Encephalopathy.

Decreased platelet count represents a feature of acute liver failure (ALF) pathogenesis. Platelets are the reservoir of transforming growth factor 1 (TGF-ß1), a multipotent cytokine involved in the maintenance of, i.a., central nervous system homeostasis. Here, we analyzed the effect of a decrease in TGF-ß1 active form on synaptic proteins levels, and brain electrophysiology, in mice after intraperitoneal (ip) administration of TGF-ß1 antibody (anti-TGF-ß1; 1 mg/mL). Next, we correlated it with a thrombocytopenia-induced TGF-ß1 decrease, documented in an azoxymethane-induced (AOM; 100 mM ip) model of ALF, and clarified the impact of TGF-ß1 decrease on blood-brain barrier functionality. The increase of both synaptophysin and synaptotagmin in the cytosolic fraction, and its reduction in a membrane fraction, were confirmed in the AOM mice brains. Both proteins' decrease in analyzed fractions occurred in anti-TGF-ß1 mice. In turn, an increase in postsynaptic (NR1 subunit of N-methyl-D-aspartate receptor, postsynaptic density protein 95, gephyrin) proteins in the AOM brain cortex, but a selective compensatory increase of NR1 subunit in anti-TGF-ß mice, was observed. The alterations of synaptic proteins levels were not translated on electrophysiological parameters in the anti-TGF-ß1 model. The results suggest the impairment of synaptic vesicles docking to the postsynaptic membrane in the AOM model. Nevertheless, changes in synaptic protein level in the anti-TGF-ß1 mice do not affect neurotransmission and may not contribute to neurologic deficits in AOM mice.

Safety of treating acute liver injury and failure.

INTRODUCTION: Acute liver injury and progression to acute liver failure can be life-threatening conditions that require prompt careful clinical assessment and therapeutic management. AREAS COVERED: The aim of this article is to review the safety and side effect profile of pharmacological therapies used in the treatment of acute liver injury with specific focus on hepatic toxicity. We performed an extensive literature search with the terms 'acute liver injury,' 'acute liver failure,' 'therapy,' 'safety,' 'adverse reactions' and 'drug induced liver injury.' A thorough discussion of the main drugs and devices used in patients with acute liver injury and acute liver failure, its safety profile and the management of complications associated to therapy of these conditions is presented. EXPERT OPINION: Several pharmacological approaches are used in acute liver injury and acute liver failure in an empirical basis. Whilst steroids are frequently tried in serious drug-induced liver injury there is concern on a potential harmful effect of these agents because of the higher mortality in patients receiving the drug; hence, statistical approaches such as propensity score matching might help resolve this clinical dilemma. Likewise, properly designed clinical trials using old and new drugs for subjects with serious drug-induced liver injury are clearly needed.

Esculetin Alleviates Acute Liver Failure following Lipopolysaccharide/D-Galactosamine in Male C57BL/6 Mice.

Background: Acute liver failure (ALF) is a fatal clinical situation that rapidly leads to the loss of normal liver function. Esculetin is a natural herbal compound used for the management of various diseases such as cardiovascular and renal disorders. In this study, we evaluated the protective effects of esculetin in a mouse model of ALF. Methods: This article is a report on an experimental study that was conducted at Iran University of Medical Sciences in 2019. Forty-eight male C57BL/6 mice were randomly divided into control, LPS/D-Gal, and LPS/D-Gal+Esculetin (40 mg/kg) groups (n=16 per group). ALF was induced with an intraperitoneal injection of lipopolysaccharide (LPS)/D-galactosamine (D-Gal).The LPS/D-Gal group received a mixture of LPS (50 µg/kg) and D-Gal (400 mg/kg). The LPS/D-Gal+Esculetin group received esculetin by gavage 24 hours and one hour before receiving LPS/D-Gal. Six hours after LPS/D-Gal injection, the mice were sacrificed. Liver injury markers, including alanine aminotransferase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP), were measured in the serum. Oxidative stress indices and inflammatory markers such as interleukin-1 beta (IL-1ß), IL-6, and tumor necrosis factor-alpha (TNF-α) were measured in hepatic tissue. The histopathology of liver tissue was also assessed. The data were analyzed using one-way ANOVA, followed by the post hoc Tukey test. Results: Esculetin lowered oxidative stress and myeloperoxidase activity (P<0.001); reduced the serum levels of ALT (P=0.037), AST (P=0.032), and ALP (P=0.004); and decreased the hepatic levels of IL-1ß (P=0.002), IL-6 (P=0.004), toll-like receptor 4 (P<0.001), TNF-α (P=0.003), and nuclear factor-kappa B (P<0.001) as compared with LPS/D-Gal. Additionally, esculetin ameliorated hepatic tissue injury following LPS/D-Gal challenge. Conclusion: Esculetin can reduce liver injury through the mitigation of oxidative burden, inflammation, and neutrophil infiltration and also exerts hepatoprotective effects against ALF.

Scrub typhus-related hepatotoxicity: The Indian scenario.

In Scrunb Typhus, hepatotoxicity is an important, yet understudied, manifestation. We reviewed studies on scrub typhus, published in the last five years (2014-2019), which evaluated its clinico-epidemiological factors in India, and concentrated on its hepatic involvement. Nine studies were found, and no Indian study exclusively evaluated hepatic dysfunction. Thus, comments from a few international studies were also included. We conclude that liver dysfunction in the form of elevated serum transaminase levels is a common manifestation of scrub typhus, which may herald progress to fulminant hepatic failure.

Contrast-Enhanced Ultrasonography-Based Hepatic Perfusion for Early Prediction of Prognosis in Acute Liver Failure.

BACKGROUND AND AIMS: Acute liver failure (ALF) is a rare but dramatic clinical syndrome characterized by massive hepatic necrosis leading to multiorgan failure. It is difficult to predict the outcomes in patients with ALF using existing prognostic models. We aimed to analyze hepatic perfusion using contrast-enhanced ultrasound and Doppler ultrasound in patients with ALF and investigate its utility as a prognostic biomarker. APPROACH AND RESULTS: In this prospective observational study, 208 patients with acute liver injury/ALF were enrolled from 2015 to 2019. We evaluated 50 consecutive patients with ALF with Doppler ultrasound and contrast-enhanced ultrasound performed on admission. The cases were divided into the following two groups: survivors (recovered without surgical intervention) and nonsurvivors (died of ALF or underwent liver transplantation). The time to peak and peak intensity of hepatic artery, portal vein, hepatic vein, and liver parenchyma were calculated using the time-intensity curve analysis. The hepatic artery (HA) resistive index was calculated using the fast Fourier transform analysis of Doppler ultrasound. The time interval (TI) between the time to peak of HA and liver parenchyma (LP) was significantly shorter in the nonsurvivors than in the survivors (P < 0.0001). The area under the receiver operating curve values for TI (HA, LP), Japanese scoring system, HE prediction model, Model for End-Stage Liver Disease score, and King's College Hospital criteria for the prediction of poor prognosis were 0.953, 0.914, 0.861, 0.816, and 0.731, respectively. The most appropriate cutoff value of TI (HA, LP) was 6.897 seconds; the sensitivity, specificity, positive and negative predictive values were 94.4%, 90.6%, 85.0%, and 96.7%, respectively. CONCLUSIONS: TI (HA, LP) accurately predicts the outcome in patients with ALF and may be useful in clinical decision making.

Novel strategies for the treatment of acetaminophen hepatotoxicity.

INTRODUCTION: Acetaminophen (APAP) hepatotoxicity is the leading cause of acute liver failure in the western world. Despite extensive investigations into the mechanisms of cell death, only a single antidote, N-acetylcysteine, is in clinical use. However, there have recently been more efforts made to translate mechanistic insight into identification of therapeutic targets and potential new drugs for this indication. AREAS COVERED: After a short review of the key events in the pathophysiology of APAP-induced liver injury and recovery, the pros and cons of targeting individual steps in the pathophysiology as therapeutic targets are discussed. While the re-purposed drug fomepizole (4-methylpyrazole) and the new entity calmangafodipir are most advanced based on the understanding of their mechanism of action, several herbal medicine extracts and their individual components are also considered. EXPERT OPINION: Fomepizole (4-methylpyrazole) is safe and has shown efficacy in preclinical models, human hepatocytes and in volunteers against APAP overdose. The safety of calmangafodipir in APAP overdose patients was shown but it lacks solid preclinical efficacy studies. Both drugs require a controlled phase III trial to achieve regulatory approval. All studies of herbal medicine extracts and components suffer from poor experimental design, which questions their clinical utility at this point.

Acute liver failure masquerading an occult malignancy.

Acute liver failure (ALF) is a rare initial presentation of metastatic liver disease and is associated with high fatality. Our case report describes acute hepatic decompensation from an occult pancreatic malignancy. A 64-year-old man presented with abdominal distension for 2 weeks associated with decreased appetite and a weight loss of 13.6 kg, over the past 8 months. Significant admission labs were serum creatinine: 6.15 mg/dL, serum bilirubin: 27 mg/dL, aspartate aminotransferase (AST): 316 u/L, alanine aminotransferase (ALT): 198 u/L and serum alkaline phosphatase: 2121 u/L. He was admitted to the medical intensive care unit and was started on dialysis for acute renal failure. MRI of the abdomen showed multiple masses in the liver concerning for metastatic disease, cystic lesions in the pancreatic body and ascites. He underwent paracentesis and ascitic fluid analysis was positive for adenocarcinoma. CA 19-9 was 17 828 u/mL. The patient's condition gradually deteriorated, and he died of cardiac arrest.

[Pediatric acute liver failure]. / Falla hepática aguda en pediatría.

Acute liver failure (ALF) is a rare and life-threatening entity in pediatrics which requires a multidis ciplinary approach for early diagnosis and treatment. The objective of this article is to update defi nitions, management, and available treatments. We obtained the articles by reviewing the literature available between 2000 and 2020 in different databases (Pubmed, LILACS, BIREME, Google Scholar, and UpToDate), using terms such as "acute liver failure" in Pubmed, and in other databases "pedia tric acute liver failure" and "falla hepática aguda en pediatría" using filters such as age, publication date, and types of study (clinical trials, review articles, systematic reviews, and case-control studies). We chose those articles with the highest number of citations and with recent data. The ALF requires support in the pediatric intensive care unit and its early diagnosis favors the beginning of treatment. In pediatric patients with ALF, it is recommended to focus on age-specific diagnostic testing. There is no agreement regarding the liver transplantation in pediatric cases of ALF.

Falla hepática aguda en pediatría / Pediatric acute liver failure

Resumen: La falla hepática aguda (FHA) es poco frecuente en pediatría, amenaza la vida y requiere aborda je multidisciplinario para su diagnóstico y tratamiento tempranos. El presente artículo tiene como objetivo realizar actualización de definiciones, enfoques y tratamientos disponibles. Los artículos se obtuvieron de la revisión de la literatura disponible entre 2000 y 2020 en varias bases de datos (Pub- med, LILACS, BIREME, Google Académico y UpToDate), empleando términos "acute liver failure" en Pubmed, "pediatric acute liver failure", "falla hepática aguda en pediatría" para otros buscadores y aplicando filtros según edad, fecha de publicación y tipo de estudio (ensayos clínicos, artículos de revisión, revisiones sistemáticas, estudios de casos y controles), se eligieron aquellos artículos con mayor número de citaciones y con datos recientes. La FHA requiere soporte en cuidado intensivo pe diátrico y su diagnóstico temprano favorece la instauración del tratamiento. Se recomienda el enfo que de pruebas diagnósticas específicas por edad en pacientes pediátricos con FHA. No hay consenso acerca de las indicaciones de trasplante hepático en FHA en pediatría.

Abstract: Acute liver failure (ALF) is a rare and life-threatening entity in pediatrics which requires a multidis ciplinary approach for early diagnosis and treatment. The objective of this article is to update defi nitions, management, and available treatments. We obtained the articles by reviewing the literature available between 2000 and 2020 in different databases (Pubmed, LILACS, BIREME, Google Scholar, and UpToDate), using terms such as "acute liver failure" in Pubmed, and in other databases "pedia tric acute liver failure" and "falla hepática aguda en pediatría" using filters such as age, publication date, and types of study (clinical trials, review articles, systematic reviews, and case-control studies). We chose those articles with the highest number of citations and with recent data. The ALF requires support in the pediatric intensive care unit and its early diagnosis favors the beginning of treatment. In pediatric patients with ALF, it is recommended to focus on age-specific diagnostic testing. There is no agreement regarding the liver transplantation in pediatric cases of ALF.

Nifuroxazide attenuates experimentally-induced hepatic encephalopathy and the associated hyperammonemia and cJNK/caspase-8/TRAIL activation in rats.

Hyperammonemia is a serious metabolic disorder associating with hepatic encephalopathy (HE) which occurs secondary to several forms of liver injury ranging from simple acute liver failure (ALF) to its most serious form; cirrhosis. The resent study highlights the possible ameliorative effect of oral nifuroxazide (25 mg/kg) against experimentally induced ALF and the subsequent HE in a well-standardized rat model. ALF and HE were induced in a rat model by I.P. injection of thioacetamide (TAA) (200 mg/kg) for 1 week at alternative days. Nifuroxazide administration for 14 days prior to and for further 7 days alongside TAA injection successfully attenuated TAA-induced ALF and HE; as demonstrated by the significant retraction in both brain and serum hyperammonemia with significant improvement in liver function biomarkers; ALT, AST, ALP, GGT, albumin, and serum total protein. This was associated with a significant restoration of both hepatic and brain oxidative stress incidences; MDA, SOD and catalase activities and GSH concentration. The observed improvement was associated with a significant reduction in liver and brain contents of c-Jun N-terminal kinase (cJNK); as an anti-inflammatory biomarker and a modulator of various pro- and anti-apoptotic proteins, caspase-8, and tumor necrosis factor-related apoptosis ligand (TRAIL); as biomarkers of apoptosis. In conclusion; the modulatory effect of nifuroxazide on cJNK/caspase-8/TRAIL signaling appears to underly its hepatoprotective effect and its ameliorative effect on HE progression.

Therapeutic targets for liver regeneration after acute severe injury: a preclinical overview.

Introduction: Liver transplantation is the only viable treatment with a proven survival benefit for acute liver failure (ALF). Donor organ shortage is, however, a major hurdle; hence, alternative approaches that enable liver regeneration and target acute severe hepatocellular damage are necessary.Areas covered: This article sheds light on therapeutic targets for liver regeneration and considers their therapeutic potential. ALF following extensive hepatocyte damage and small-for-size syndrome (SFSS) are illuminated for the reader while the molecular mechanisms of liver regeneration are assessed in accordance with relevant therapeutic strategies. Furthermore, liver background parameters and predictive biomarkers that might associate with liver regeneration are reviewed.Expert opinion: There are established and novel experimental strategies for liver regeneration to prevent ALF resulting from SFSS. Granulocyte-colony stimulating factor (G-CSF) is a promising agent targeting liver regeneration after acute severe injury. Autophagy and hepatocyte senescence represent attractive new targets for liver regeneration in acute severe hepatic injury. Liver support strategies, including tissue engineering, constitute novel regenerative means; the success of this is dependent on stem cell research advances. However, there is no firm clinical evidence that these supportive strategies may alleviate hepatocellular damage until liver transplantation becomes available or successful self-liver regeneration occurs.

Human liver regeneration following massive hepatic necrosis: Two distinct patterns.

BACKGROUND AND AIM: Massive hepatic necrosis is a rare but often fatal complication of various liver injuries. Nevertheless, some patients can survive by spontaneous hepatic regeneration. It is known that surviving hepatocytes and/or progenitor cells can participate in this process but the mechanism of hepatic recovery is vague. METHODS: We examined 13 explanted human livers removed for acute liver failure. Combined immunohistochemistry, digital image analysis, and three-dimensional reconstruction of serial sections were applied. RESULTS: Two patterns of regeneration could be distinguished. In livers with centrilobular necrosis, the surviving injured periportal hepatocytes started to proliferate and arrange into acinar structures and expressed α-fetoprotein. If the injury wiped out almost all hepatocytes, large areas of parenchymal loss were invaded by an intense ductular reaction. The cells at the distal pole of the ductules differentiated into hepatocytes and formed foci organized by the branches of the portal vein. The expanding foci often containing complete portal triads were arranged around surviving central veins. Their fusion eventually could be an attempt to re-establish the hepatic lobules. CONCLUSIONS: Regeneration of human livers following massive hepatic necrosis can occur in two ways-either through proliferation of α-fetoprotein-positive acinary-arranged hepatocytes or through ductular progenitor cells, with the latter being less efficient. Further investigation of these regenerative pathways may help identify biomarkers for likelihood of complete regeneration and hence have therapeutic implications.

Pathophysiology of Acute Liver Failure.

Acute liver failure (ALF) is a rare syndrome resulting from an acute insult to the liver in patients without known underlying chronic liver disease. It is characterized by loss of synthetic function in the form of jaundice and coagulopathy and development of hepatic encephalopathy. Multiorgan failure (MOF) eventually develops, leading to death. Many different etiologies have been identified, with acetaminophen (APAP) overdose and viral hepatitis being the most common causes worldwide. The pathophysiology of ALF can be divided into cause-specific liver injury pathophysiologies and pathophysiology related to occurrence of secondary MOF. In terms of liver injury pathophysiology, APAP toxicity is the most well known. Secondary MOF is often a result of the initial massive proinflammatory response generating a systemic inflammatory response syndrome followed by a compensatory anti-inflammatory response leading to immune cell dysfunction and sepsis. As the liver is a tremendously important metabolic organ involved in energy metabolism, protein synthesis, fat metabolism, and glycemic control, multiple aspects of nutrition also need to be considered as part of the overall pathophysiology of ALF.

Bone marrow mesenchymal stem cell-derived exosomes attenuate D-GaIN/LPS-induced hepatocyte apoptosis by activating autophagy in vitro.

BACKGROUND: Acute liver failure is an inflammation-mediated hepatocyte injury. Mesenchymal stem cell (MSC) transplantation is currently considered to be an effective treatment strategy for acute liver failure. Exosomes are an important paracrine factor that can be used as a direct therapeutic agent. However, the use of bone marrow mesenchymal stem cell-derived exosomes (BMSC-Exos) in the treatment of acute liver failure has not been reported. PURPOSE: Here, we established a model of hepatocyte injury and apoptosis induced by D-galactosamine and lipopolysaccharide (D-GalN/LPS) to study the protective effect of BMSC-Exos on hepatocyte apoptosis, and further explored its protective mechanism. METHODS: BMSC-Exos was identified by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and Western blot. Laser confocal microscopy was used to observe the uptake of Dil-Exos by hepatocytes. D-GalN/LPS-induced primary hepatocytes were pretreated with BMSC-Exos in vitro, and then the cells were harvested. The apoptosis of hepatocytes was observed by TUNEL staining, flow cytometry and Western blot. Electron microscopy and mRFP-GFP-LC3 and Western blot was used to observe autophagy. RESULTS: BMSC-Exos increased the expression of autophagy marker proteins LC3 and Beclin-1 and promoted the formation of autophagosomes. After BMSC-Exos treatment, the expression levels of the proapoptotic proteins Bax and cleaved caspase-3 were significantly decreased, while the expression level of the anti-apoptotic protein Bcl-2 was upregulated. However, when the autophagy inhibitor 3MA was present, the effect of BMSC-Exos on inhibiting apoptosis was significantly reversed. CONCLUSIONS: Our results showed for the first time that BMSC-Exos had the potential to reduce hepatocyte apoptosis after acute liver failure. In particular, we found that BMSC-Exos attenuated hepatocyte apoptosis by promoting autophagy.