Alcoholic and non-alcoholic steatohepatitis

Role of AMPK-SREBP Signaling in Regulating Fatty Acid Binding-4 (FABP4) Expression following Ethanol Metabolism

Fatty acid binding protein-4 (FABP4) is not normally expressed in the liver but is induced in alcohol-dependent liver disease (ALD)). This study sought to identify mechanisms whereby ethanol (EtOH) metabolism alters triglyceride accumulation and FABP4 production. Human hepatoma cells which were stably transfected to express alcohol dehydrogenase (ADH) or cytochrome P4502E1 (CYP2E1) were exposed to EtOH in the absence/presence of inhibitors of ADH (4-methylpyrazole) or CYP2E1 (chlormethiazole). Cells were analyzed for free fatty acid (FFA) content and FABP4 mRNA, then culture medium assayed for FABP4 levels. Cell lysates were analyzed for AMP-activated protein kinase-α (AMPKα), Acetyl-CoA carboxylase (ACC), sterol regulatory element binding protein-1c (SREBP-1c), and Lipin-1β activity and localization in the absence/presence of EtOH and pharmacological inhibitors. CYP2E1-EtOH metabolism led to increased FABP4 mRNA/protein expression and FFA accumulation. Analysis of signaling pathway activity revealed decreased AMPKα activation and increased nuclear-SREBP-1c localization following CYP2E1-EtOH metabolism. The role of AMPKα-SREBP-1c in regulating CYP2E1-EtOH-dependent FFA accumulation and increased FABP4 was confirmed using pharmacological inhibitors and over-expression of AMPKα. Inhibition of ACC or Lipin-1β failed to prevent FFA accumulation or changes in FABP4 mRNA expression or protein secretion. These data suggest that CYP2E1-EtOH metabolism inhibits AMPKα phosphorylation to stimulate FFA accumulation and FABP4 protein secretion via an SREBP-1c dependent mechanism.

Molecular, Viral and Clinical Features of Alcohol- and Non-Alcohol-Induced Liver Injury

Hepatic cells are sensitive to internal and external signals. Ethanol is one of the oldest and most widely used drugs in the world. The focus on the mechanistic engine of the alcohol-induced injury has been in the liver, which is responsible for the pathways of alcohol metabolism. Ethanol undergoes a phase I type of reaction, mainly catalyzed by the cytoplasmic enzyme, alcohol dehydrogenase (ADH), and by the microsomal ethanol-oxidizing system (MEOS). Reactive oxygen species (ROS) generated by cytochrome (CYP) 2E1 activity and MEOS contribute to ethanol-induced toxicity. We aimed to: (1) Describe the cellular, pathophysiological and clinical effects of alcohol misuse on the liver; (2) Select the biomarkers and analytical methods utilized by the clinical laboratory to assess alcohol exposure; (3) Provide therapeutic ideas to prevent/reduce alcohol-induced liver injury; (4) Provide up-to-date knowledge regarding the Corona virus and its affect on the liver; (5) Link rare diseases with alcohol consumption. The current review contributes to risk identification of patients with alcoholic, as well as non-alcoholic, liver disease and metabolic syndrome. Additional prevalence of ethnic, genetic, and viral vulnerabilities are presented.

Inhibition of GCN2 alleviates hepatic steatosis and oxidative stress in obese mice: Involvement of NRF2 regulation

The development of nonalcoholic fatty liver disease (NAFLD) is associated with increased reactive oxygen species (ROS) production. Previous observations on the contradictory roles of general control nonderepressible 2 (GCN2) in regulating the hepatic redox state under different nutritional conditions prompted an investigation of the underlying mechanism by which GCN2 regulates ROS homeostasis. In the present study, GCN2 was found to interact with NRF2 and decrease NRF2 expression in a KEAP1-dependent manner. Activation of GCN2 by halofuginone treatment or leucine deprivation decreased NRF2 expression in hepatocytes by increasing GSK-3β activity. In response to oxidative stress, GCN2 repressed NRF2 transcriptional activity. Knockdown of hepatic GCN2 by tail vein injection of an AAV8-shGcn2 vector attenuated hepatic steatosis and oxidative stress in leptin-deficient (ob/ob) mice in an NRF2-dependent manner. Inhibition of GCN2 by GCN2iB also ameliorated hepatic steatosis and oxidative stress in both ob/ob mice and high fat diet-fed mice, which was associated with significant changes in lipid and amino acid metabolic pathways. Untargeted metabolomics analysis revealed that GCN2iB decreased fatty acid and sphingomyelin levels but increased aliphatic amino acid and phosphatidylcholine levels in fatty livers. Collectively, our results provided the first direct evidence that GCN2 is a novel regulator of NRF2 and that specific GCN2 inhibitors might be potential drugs for NAFLD therapy.

Priming, Triggering, Adaptation and Senescence (PTAS): A Hypothesis for a Common Damage Mechanism of Steatohepatitis

Understanding the pathomechanism of steatohepatitis (SH) is hampered by the difficulty of distinguishing between causes and consequences, by the broad spectrum of aetiologies that can produce the phenotype, and by the long time-span during which SH develops, often without clinical symptoms. We propose that SH develops in four phases with transitions: (i) priming lowers stress defence; (ii) triggering leads to acute damage; (iii) adaptation, possibly associated with cellular senescence, mitigates tissue damage, leads to the phenotype, and preserves liver function at a lower level; (iv) finally, senescence prevents neoplastic transformation but favours fibrosis (cirrhosis) and inflammation and further reduction in liver function. Escape from senescence eventually leads to hepatocellular carcinoma. This hypothesis for a pathomechanism of SH is supported by clinical and experimental observations. It allows organizing the various findings to uncover remaining gaps in our knowledge and, finally, to provide possible diagnostic and intervention strategies for each stage of SH development.

Non-invasive Biomarkers of Liver Inflammation and Cell Death in Response to Alcohol Detoxification

Introduction

Alcohol-related liver disease (ALD) represents the most common liver disease worldwide, however, the underlying molecular mechanisms are still poorly understood. Namely centrilobular inflammation and programmed cell death are characteristic to ALD and it remains to be elucidated why they persist despite the absence of alcohol.

Aims

To study the effects of alcohol withdrawal in a cohort of heavy drinkers and the role of cirrhosis by using non-invasive biomarkers such as cytokines, apoptotic and angiogenic markers.

Methods

Caspase 3-cleaved M30, M65, cytokines (IL-6, IL-8), tumor necrosis factor alpha (TNF-α), transforming growth factor (TGF-β) and vascular endothelial growth factor (VEGF) were measured in 114 heavy drinkers. The role of alcohol detoxification was investigated in 45 patients. The liver histology was available in 23 patients. Fibrosis stage and steatosis were assessed by measuring liver stiffness (LS) and controlled attenuation parameter (CAP) in all patients using transient elastography (FibroScan, Echosens, Paris). Mean observation interval between the measurements was 5.7 ± 1.4 days (mean + -SD).

Results

Patients consumed a mean of 204 ± 148 g/day alcohol with a heavy drinking duration of 15.3 ± 11.0 years. Mean LS was 20.7 ± 24.4 kPa and mean CAP was 303 ± 51 dB/m. Fibrosis distribution was F0-38.1%, F1-2-31%, F3-7.1 and F4-23.9%. Apoptotic markers M30 and M65 were almost five times above normal. In contrast, TNF- α a, IL-8 and VEGF were only slightly elevated. Patients with manifest liver cirrhosis (F4) had significantly higher levels of M30, M65, IL-6 and IL-8. Histology features such as hepatocyte ballooning, Mallory-Denk bodies, inflammation and fibrosis were all significantly associated with elevated LS, and serum levels of TNF-alpha, M30 and M65 but not with CAP and other cytokines. During alcohol detoxification, LS, transaminases, TGF- β, IL-6, IL-8 and VEGF decreased significantly. In contrast, no significant changes were observed for M30, M65 and TNF- α and M30 even increased during detoxification in non-cirrhotic patients. Profibrogenic cytokine TGF-beta and pro-angiogenic cytokine VEGF showed a delayed decrease in patients with manifest cirrhosis.

Conclusion

Patients with alcohol-related cirrhosis have a pronounced apoptotic activity and a distinct inflammatory response that only partly improves after 1 week of alcohol detoxification. Alcohol withdrawal may represent an important approach to better dissect the underlying mechanisms in the setting of alcohol metabolism.

Effect of Betaine Supplementation on Liver Tissue and Ultrastructural Changes in Methionine-Choline-Deficient Diet-Induced NAFLD

Nonalcoholic fatty liver disease (NAFLD) represents a hepatic manifestation of metabolic syndrome. The aim of this study was to examine the effect of betaine on ultrastructural changes in the mouse liver with methionine- and choline-deficient (MCD) diet-induced NAFLD. Male C57BL/6 mice were divided into groups: Control-fed with standard chow, BET-standard chow supplemented with betaine (1.5% w/v drinking water), MCD-fed with MCD diet, and MCD + BET-MCD diet with betaine supplementation for 6 weeks. Liver samples were taken for pathohistology and transmission electron microscopy. The MCD diet-induced steatosis, inflammation, and balloon-altered hepatocytes were alleviated by betaine. MCD diet induced an increase in mitochondrial size versus the control group (p < 0.01), which was decreased in the betaine-treated group. In the MCD diet-fed group, the total mitochondrial count decreased versus the control group (p < 0.01), while it increased in the MCD + BET group versus MCD (p < 0.01). Electron microscopy showed an increase in the number of autophagosomes in the MCD and MCD + BET group versus control, and a significant difference in autophagosomes number was detected in the MCD + BET group by comparison with the MCD diet-treated group (p < 0.05). Betaine decreases the number of enlarged mitochondria, alleviates steatosis, and increases the number of autophagosomes in the liver of mice with NAFLD.

Mitophagy in Human Diseases

Mitophagy is a selective autophagic process, essential for cellular homeostasis, that eliminates dysfunctional mitochondria. Activated by inner membrane depolarization, it plays an important role during development and is fundamental in highly differentiated post-mitotic cells that are highly dependent on aerobic metabolism, such as neurons, muscle cells, and hepatocytes. Both defective and excessive mitophagy have been proposed to contribute to age-related neurodegenerative diseases, such as Parkinson’s and Alzheimer’s diseases, metabolic diseases, vascular complications of diabetes, myocardial injury, muscle dystrophy, and liver disease, among others. Pharmacological or dietary interventions that restore mitophagy homeostasis and facilitate the elimination of irreversibly damaged mitochondria, thus, could serve as potential therapies in several chronic diseases. However, despite extraordinary advances in this field, mainly derived from in vitro and preclinical animal models, human applications based on the regulation of mitochondrial quality in patients have not yet been approved. In this review, we summarize the key selective mitochondrial autophagy pathways and their role in prevalent chronic human diseases and highlight the potential use of specific interventions.

Bile acids profile, histopathological indices and genetic variants for non-alcoholic fatty liver disease progression

OBJECTIVE

Metabolomic studies suggest plasma levels of bile acids (BAs) are elevated amongst subjects with non-alcoholic fatty liver disease (NAFLD) compared to healthy controls. However, it remains unclear whether or not specific BAs are associated with the clinically relevant transition from nonalcoholic fatty liver (i.e. simple steatosis) to non-alcoholic steatohepatitis (NASH), or enhanced progression of hepatic fibrosis, or genetic determinants of NAFLD/NASH.

METHODS

Among sequential subjects (n=102) undergoing diagnostic liver biopsy, we examined the associations of a broad panel of BAs with distinct histopathological features of NAFLD, the presence of NASH, and their associations with genetic variants linked to NAFLD and NASH.

RESULTS

Plasma BA alterations were observed through the entire spectrum of NAFLD, with several glycine conjugated forms of the BAs demonstrating significant associations with higher grades of inflammation and fibrosis. Plasma 7-Keto-DCA levels showed the strongest associations with advanced stages of hepatic fibrosis [odds ratio(95% confidence interval)], 4.2(1.2-16.4), NASH 24.5(4.1-473), and ballooning 18.7(4.8-91.9). Plasma 7-Keto-LCA levels were associated with NASH 9.4(1.5-185) and ballooning 5.9(1.4-28.8). Genetic variants at several NAFLD/NASH loci were nominally associated with increased levels of 7-Keto- and glycine-conjugated forms of BAs, and the NAFLD risk allele at the TRIB1 locus showed strong tendency toward increased plasma levels of GCA (p=0.02) and GUDCA (p=0.009).

CONCLUSIONS

Circulating bile acid levels are associated with histopathological and genetic determinants of the transition from simple hepatic steatosis into NASH. Further studies exploring the potential involvement of bile acid metabolism in the development and/or progression of distinct histopathological features of NASH are warranted.

Alcohol-associated liver disease: A review on its pathophysiology, diagnosis and drug therapy

One of the global burdens of health care is an alcohol-associated liver disease (ALD) and liver-related death which is caused due to acute or chronic consumption of alcohol. Chronic consumption of alcohol damage the normal defense mechanism of the liver and likely to disturb the gut barrier system, mucosal immune cells, which leads to decreased nutrient absorption. Therapy of ALD depends upon the spectrum of liver injury that causes fatty liver, hepatitis, and cirrhosis. The foundation of therapy starts with abstinence from alcohol. Corticosteroids are used for the treatment of ALD but due to poor acceptance, continuing mortality, and identification of tumor necrosis factor-alpha as an integral component in pathogenesis, recent studies focus on pentoxifylline and, antitumor necrosis factor antibody to neutralize cytokines in the therapy of severe alcoholic hepatitis. Antioxidants also play a significant role in the treatment but till today there is no universally accepted therapy available for any stage of ALD. The treatment aspects need to restore the gut functions and require nutrient-based treatments to regulate the functions of the gut system and prevent liver injury. The vital action of saturated fatty acids greatly controls the gut barrier. Overall, this review mainly focuses on the mechanism of alcohol-induced metabolic dysfunction, contribution to liver pathogenesis, the effect of pregnancy, and targeted therapy of ALD.

Acute Elevated Resistin Exacerbates Mitochondrial Damage and Aggravates Liver Steatosis Through AMPK/PGC-1α Signaling Pathway in Male NAFLD Mice

Resistin was identified as a link between obesity and insulin resistance and is associated with many diseases in mice. Deciphering the related development and molecular mechanism is necessary for the treatment of these diseases. Previous studies have revealed that increased resistin levels are correlated with lipid accumulation and play a role in non-alcoholic fatty liver disease (NAFLD) development. However, the exact mechanisms underlying these processes remain unclear. To further clarify whether acute elevated resistin level exacerbated liver steatosis, a high-fat diet-induced NAFLD animal model was used and treated with or without resistin for 6 days. We discovered that resistin altered mitochondrial morphology, decreased mitochondrial content, and increased lipid accumulation in HFD mice. qRT-PCR and western blot analysis showed that acute elevated resistin significantly altered the gene expression of mitochondrial biogenesis and liver lipid metabolism molecules in HFD mice. Consequently, in vitro experiments verified that resistin reduced the mitochondrial content, impaired the mitochondrial function and increased the lipid accumulation of palmitate-treated HepG2 cells. Additionally, we demonstrated that resistin upregulated proinflammatory factors, which confirmed that resistin promoted the development of inflammation in NAFLD mice and palmitate-treated HepG2 cells. Signaling-transduction analysis demonstrated that acute elevated resistin aggravated liver steatosis through AMPK/PGC-1α pathway in male mice. This reveals a novel pathway through which lipogenesis is induced by resistin and suggests that maintaining mitochondrial homeostasis may be key to treatments for preventing resistin-induced NAFLD aggravation.

Molecular mechanisms and physiological functions of mitophagy

Degradation of mitochondria via a selective form of autophagy, named mitophagy, is a fundamental mechanism conserved from yeast to humans that regulates mitochondrial quality and quantity control. Mitophagy is promoted via specific mitochondrial outer membrane receptors, or ubiquitin molecules conjugated to proteins on the mitochondrial surface leading to the formation of autophagosomes surrounding mitochondria. Mitophagy-mediated elimination of mitochondria plays an important role in many processes including early embryonic development, cell differentiation, inflammation, and apoptosis. Recent advances in analyzing mitophagy in vivo also reveal high rates of steady-state mitochondrial turnover in diverse cell types, highlighting the intracellular housekeeping role of mitophagy. Defects in mitophagy are associated with various pathological conditions such as neurodegeneration, heart failure, cancer, and aging, further underscoring the biological relevance. Here, we review our current molecular understanding of mitophagy, and its physiological implications, and discuss how multiple mitophagy pathways coordinately modulate mitochondrial fitness and populations.

Sagittaria sagittifolia polysaccharide interferes with arachidonic acid metabolism in non-alcoholic fatty liver disease mice via Nrf2/HO-1 signaling pathway

BACKGROUNDS

Non-alcoholic fatty liver disease (NAFLD) is currently one of the most common chronic liver diseases especially in developed countries. Modern research shows an obvious protective effect of Sagittaria sagittifolia L. (Alismataceae) on glucose and lipid metabolism disorders. Previous studies had reported that Sagittaria sagittifolia polysaccharide (SSP) has potent protective effects on drug-induced liver injury. Based on this, we speculated that Sagittaria sagittifolia polysaccharide also has protective effects on NAFLD and performed experiments to explore this more.

METHODS

Outstanding protective effects of SSP against NAFLD in mice was observed with Hematoxylin and Eosin (H&E) and uranium acetate-citrate stain in our prophase research. By performing bioinformatics analysis on plasma metabolic data which is obtained from ultra-performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS), we found the regulatory mechanisms and key nodes behind the beneficial effect with IPA (Ingenuity Pathway Analysis) software. Immunohistochemical staining and Western blot were performed for further validation on expression variations of key proteins.

RESULTS

Regulatory pathways were enriched with 33 significant differential metabolites that responded to SSP treatment in plasma, and specifically, the ones related to arachidonic acid metabolism showed high participation. Moreover, the expression patterns of upstream regulators, Nrf2 and HO-1, were found to be significantly regulated upon SSP treatment.

CONCLUSIONS

In conclusion, our findings illustrated a novel perspective that SSP exerts preventive protection against high-fat diet-induced NAFLD by interfering with arachidonic acid metabolism via Nrf2/HO-1 signaling pathway in liver oxidative stress, providing an attractive point for the breakthrough of related natural medicine development.

Non-alcoholic Fatty Liver Disease and Alcohol-Related Liver Disease: Two Intertwined Entities

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide, with a prevalence of 25-30%. Since its first description in 1980, NAFLD has been conceived as a different entity from alcohol-related fatty liver disease (ALD), despite that, both diseases have an overlap in the pathophysiology, share genetic-epigenetic factors, and frequently coexist. Both entities are characterized by a broad spectrum of histological features ranging from isolated steatosis to steatohepatitis and cirrhosis. Distinction between NAFLD and ALD is based on the amount of consumed alcohol, which has been arbitrarily established. In this context, a proposal of positive criteria for NAFLD diagnosis not considering exclusion of alcohol consumption as a prerequisite criterion for diagnosis had emerged, recognizing the possibility of a dual etiology of fatty liver in some individuals. The impact of moderate alcohol use on the severity of NAFLD is ill-defined. Some studies suggest protective effects in moderate doses, but current evidence shows that there is no safe threshold for alcohol consumption for NAFLD. In fact, given the synergistic effect between alcohol consumption, obesity, and metabolic dysfunction, it is likely that alcohol use serves as a significant risk factor for the progression of liver disease in NAFLD and metabolic syndrome. This also affects the incidence of hepatocellular carcinoma. In this review, we summarize the overlapping pathophysiology of NAFLD and ALD, the current data on alcohol consumption in patients with NAFLD, and the effects of metabolic dysfunction and overweight in ALD.

Nuclear ErbB2 expression in hepatocytes in liver disease

ErbB2 is a prominent representative of the epidermal growth factor receptors that mainly attract attention as oncogenic drivers and therapeutic targets in cancer. Besides transmembrane signaling, ErbB2 may also translocate into the nucleus and mediate distinct nuclear signaling effects including DNA repair and cell cycle arrest. Unexpectedly, we found nuclear ErbB2 expression in human hepatocytes in various liver diseases so we aimed to investigate the characteristics of liver disease leading to nuclear ErbB2 translocation. The immunohistochemical pattern of ErbB2 staining was analyzed in 1125 liver biopsy samples from patients with hepatic dysfunction. Further signaling and metabolic markers were analyzed by immunohistochemistry in selected liver biopsy samples. We found a cytoplasmic and nuclear ErbB2 expression in hepatocytes from different disease conditions with the strongest expression detected in alcoholic steatohepatitis. Nuclear ErbB2 positivity significantly correlated with histologic parameters of hepatocellular damage including inflammatory activity in steatohepatitis, hepatocellular ballooning, and cholestasis. ErbB2 overexpressing hepatocytes revealed an increase of phospho-STAT3, a downstream effector of nuclear ErbB2 signaling. Notably, we observed in nuclear ErbB2-positive hepatocytes a downregulation of estrogen receptor expression. In alcoholic steatohepatitis and other toxic liver diseases, hepatocytes revealed a nuclear ErbB2 expression implying a so far unknown mechanism in hepatocytes upon cellular stress that might lead to resistance to cell death. Nuclear ErbB2-positive hepatocytes showed downregulation of estrogen receptor expression and increased levels of pSTAT3, which are signs of functionality of nuclear ErbB2 signaling. Furthermore, analysis of hepatocellular ErbB2 expression could serve as helpful tool for diagnosis of liver disease.

Alcoholic-Hepatitis, Links to Brain and Microbiome: Mechanisms, Clinical and Experimental Research

The following review article presents clinical and experimental features of alcohol-induced liver disease (ALD). Basic aspects of alcohol metabolism leading to the development of liver hepatotoxicity are discussed. ALD includes fatty liver, acute alcoholic hepatitis with or without liver failure, alcoholic steatohepatitis (ASH) leading to fibrosis and cirrhosis, and hepatocellular cancer (HCC). ALD is fully attributable to alcohol consumption. However, only 10-20% of heavy drinkers (persons consuming more than 40 g of ethanol/day) develop clinical ALD. Moreover, there is a link between behaviour and environmental factors that determine the amount of alcohol misuse and their liver disease. The range of clinical presentation varies from reversible alcoholic hepatic steatosis to cirrhosis, hepatic failure, and hepatocellular carcinoma. We aimed to (1) describe the clinico-pathology of ALD, (2) examine the role of immune responses in the development of alcoholic hepatitis (ASH), (3) propose diagnostic markers of ASH, (4) analyze the experimental models of ALD, (5) study the role of alcohol in changing the microbiota, and (6) articulate how findings in the liver and/or intestine influence the brain (and/or vice versa) on ASH; (7) identify pathways in alcohol-induced organ damage and (8) to target new innovative experimental concepts modeling the experimental approaches. The present review includes evidence recognizing the key toxic role of alcohol in ALD severity. Cytochrome p450 CYP2E1 activation may change the severity of ASH. The microbiota is a key element in immune responses, being an inducer of proinflammatory T helper 17 cells and regulatory T cells in the intestine. Alcohol consumption changes the intestinal microbiota and influences liver steatosis and liver inflammation. Knowing how to exploit the microbiome to modulate the immune system might lead to a new form of personalized medicine in ALF and ASH.

The hepatic lipidome: From basic science to clinical translation

The liver is the key organ involved in lipid metabolism and transport. Excessive lipid accumulation due to dysregulated lipid metabolism predisposes the liver to steatosis, cirrhosis, and hepatocellular carcinoma. Lipids are generally compartmentalized in specialized organelles called lipid droplets that enable cells to store and release lipids in a regulated manner. However, during flux-in and flux-out of droplets, lipids are converted into toxic species leading to lipid-mediated liver damage. Lipids are categorized into 'toxic' or 'healthy' lipids that are involved in liver disease pathogenesis or resolution, respectively. Lipidomic analysis have revealed unique lipid signature that correlates with the disease progression therefore being used for disease diagnosis. In this comprehensive review, we provide an overview on hepatic lipid homeostasis, lipid compartmentalization mechanisms and lipidomic profiles in different liver diseases. We further discuss promising therapeutics targeting the hepatic lipidome including pro-resolving lipids, liposomes, and small-molecule inhibitors for the treatment of liver diseases.

Diagnostic Biomarkers in Liver Injury by Drugs, Herbs, and Alcohol: Tricky Dilemma after EMA Correctly and Officially Retracted Letter of Support

Liver injuries caused by the use of exogenous compounds such as drugs, herbs, and alcohol are commonly well diagnosed using laboratory tests, toxin analyses, or eventually reactive intermediates generated during metabolic degradation of the respective chemical in the liver and subject to covalent binding by target proteins. Conditions are somewhat different for idiosyncratic drug induced liver injury (DILI), for which metabolic intermediates as diagnostic aids are rarely available. Although the diagnosis of idiosyncratic DILI can well be established using the validated, liver specific, structured, and quantitative RUCAM (Roussel Uclaf Causality Assessment Method), there is an ongoing search for new diagnostic biomarkers that could assist in and also confirm RUCAM-based DILI diagnoses. With respect to idiosyncratic DILI and following previous regulatory letters of recommendations, selected biomarkers reached the clinical focus, including microRNA-122, microRNA-192, cytokeratin analogues, glutamate dehydrogenase, total HMGB-1 (High Mobility Group Box), and hyperacetylated HMGB-1 proteins. However, the new parameters total HMGB-1, and even more so the acetylated HMGB-1, came under critical scientific fire after misconduct at one of the collaborating partner centers, leading the EMA to recommend no longer the exploratory hyperacetylated HMGB1 isoform biomarkers in clinical studies. The overall promising nature of the recommended biomarkers was considered by EMA as highly dependent on the outstanding results of the now incriminated biomarker hyperacetylated HMGB-1. The EMA therefore correctly decided to officially retract its Letter of Support affecting all biomarkers listed above. New biomarkers are now under heavy scrutiny that will require re-evaluations prior to newly adapted recommendations. With Integrin beta 3 (ITGB3), however, a new diagnostic biomarker may emerge, possibly being drug specific but tested in only 16 patients; due to substantial remaining uncertainties, final recommendations would be premature. In conclusion, most of the currently recommended new biomarkers have lost regulatory support due to scientific misconduct, requiring now innovative approaches and re-evaluation before they can be assimilated into clinical practice.

Glutathione deficiency-elicited reprogramming of hepatic metabolism protects against alcohol-induced steatosis

Depletion of glutathione (GSH) is considered a critical pathogenic event promoting alcohol-induced lipotoxicity. We recently show that systemic GSH deficiency in mice harboring a global disruption of the glutamate-cysteine ligase modifier subunit (Gclm) gene confers protection against alcohol-induced steatosis. While several molecular pathways have been linked to the observed hepatic protection, including nuclear factor erythroid 2-related factor 2 and AMP-activated protein kinase pathways, the precise mechanisms are yet to be defined. In this study, to gain insights into the molecular mechanisms underpinning the protective effects of loss of GCLM, global profiling of hepatic polar metabolites combined with liver microarray analysis was carried out. These inter-omics analyses revealed both low GSH- and alcohol-driven changes in multiple cellular pathways involving the metabolism of amino acids, fatty acid, glucose and nucleic acids. Notably, several metabolic changes were uniquely present in alcohol-treated Gclm-null mouse livers, including acetyl-CoA enrichment and diversion of acetyl-CoA flux from lipogenesis to alterative metabolic pathways, elevation in glutamate concentration, and induction of the glucuronate pathway and nucleotide biosynthesis. These metabolic features reflect low GSH-elicited cellular response to chronic alcohol exposure, which is beneficial for the maintenance of hepatic redox and metabolic homeostasis. The current study indicates that fine-tuning of hepatic GSH pool may evoke metabolic reprogramming to cope with alcohol-induced cellular stress.

Antidotes Against Methanol Poisoning: A Review

Methanol is the simplest alcohol. Compared to ethanol that is fully detoxified by metabolism. Methanol gets activated in toxic products by the enzymes, alcohol dehydrogenase and aldehyde dehydrogenase. Paradoxically, the same enzymes convert ethanol to harmless acetic acid. This review is focused on a discussion and overview of the literature devoted to methanol toxicology and antidotal therapy. Regarding the antidotal therapy, three main approaches are presented in the text: 1) ethanol as a competitive inhibitor in alcohol dehydrogenase; 2) use of drugs like fomepizole inhibiting alcohol dehydrogenase; 3) tetrahydrofolic acid and its analogues reacting with the formate as a final product of methanol metabolism. All the types of antidotal therapies are described and how they protect from toxic sequelae of methanol is explained.

Endoplasmic reticulum stress in the livers of BDNF heterozygous knockout mice

Context: Involvement of endoplasmic reticulum (ER) stress and brain-derived neurotrophic factor (BDNF) in hepatic lipid metabolism has been reported previously. Objective: The effects of chronic BDNF deficiency on ER stress response in the livers were examined in this study. Methods: BDNF^(+/-) mice, characterised by BDNF deficiency, and their wild-type (WT) littermates were used. The ER stress was induced by tunicamycin (Tm) (0.5 mg/kg, intraperitoneal). Animals were divided into four groups; WT, WT + Tm, BDNF^(+/-), and BDNF^(+/-)+Tm. Results: At the basal conditions, BDNF deficiency did not affect hepatic cell death or lipid accumulation. However, during ER stress, BDNF^(+/-)+Tm group showed increased apoptosis, GADD153 immunostaining, sterol regulatory element-binding protein-1c (SREBP-1c) level, and steatosis compared to the WT + Tm group. Conclusion: Endogenous BDNF might be protective against apoptosis through GADD153 suppression and steatosis via SREBP-1c suppression during ER stress. This effect of BDNF might be clinically important for type 2 diabetes and obesity, which are related with both ER stress and BDNF deficiency.

Alcoholic Liver Disease: Current Mechanistic Aspects with Focus on Their Clinical Relevance

The spectrum of alcoholic liver disease (ALD) is broad and includes alcoholic fatty liver, alcoholic steatohepatitis, alcoholic hepatitis, alcoholic fibrosis, alcoholic cirrhosis, and alcoholic hepatocellular carcinoma, best explained as a five-hit sequelae of injurious steps. ALD is not primarily the result of malnutrition as assumed for many decades but due to the ingested alcohol and its metabolic consequences although malnutrition may marginally contribute to disease aggravation. Ethanol is metabolized in the liver to the heavily reactive acetaldehyde via the alcohol dehydrogenase (ADH) and the cytochrome P450 isoform 2E1 of the microsomal ethanol-oxidizing system (MEOS). The resulting disturbances modify not only the liver parenchymal cells but also non-parenchymal cells such as Kupffer cells (KCs), hepatic stellate cells (HSCs), and liver sinusoidal endothelial cells (LSECs). These are activated by acetaldehyde, reactive oxygen species (ROS), and endotoxins, which are produced from bacteria in the gut and reach the liver due to gut leakage. A variety of intrahepatic signaling pathways and innate or acquired immune reactions are under discussion contributing to the pathogenesis of ALD via the five injurious hits responsible for disease aggravation. As some of the mechanistic steps are based on studies with in vitro cell systems or animal models, respective proposals for humans may be considered as tentative. However, sufficient evidence is provided for clinical risk factors that include the amount of alcohol used daily for more than a decade, gender differences with higher susceptibility of women, genetic predisposition, and preexisting liver disease. In essence, efforts within the last years were devoted to shed more light in the pathogenesis of ALD, much has been achieved but issues remain to what extent results obtained from experimental studies can be transferred to humans.

Increasing efficacy of treatment in patients with steatohepatitis and concomitant chronic colitis

This paper presents the results of a study of patients with nonalcoholic steatohepatitis, alcoholic steatohepatitis, and drug-induced liver injury with concomitant colitis and the development of biliary insufficiency that manifests as a significant decrease in the volume of bile acids and bile. In patients with liver injury and concomitant colitis, changes in intestinal microflora were marked. After a combination therapy of this pathology with phosphatidylcholine and glycyrrhizic acid, an improvement of biochemical, clinical indicators was observed, as well as a decrease in fatty degeneration and reduction of elastographic indicators of liver fibrosis. The introduction of the drug formulations phosphatidylcholine and glycyrrhizic acid in the complex of conservative treatment of liver injury with concomitant colitis helps to prevent hepatic and intestinal complications and to increase the treatment efficacy of these diseases.

Regulatory T cells suppress excessive lipid accumulation in alcoholic liver disease

Sensitization of hepatic immune cells from chronic alcohol consumption gives rise to inflammatory accumulation, which is considered a leading cause of liver damage. Regulatory T cells (Tregs) are an immunosuppressive cell subset that plays an important role in a variety of liver diseases; however, data about pathological involvement of Tregs in liver steatosis of alcoholic liver disease (ALD) is insufficient. In mouse models of ALD, we found that increased lipid accumulation by chronic alcohol intake was accompanied by oxidative stress, inflammatory accumulation, and Treg decline in the liver. Adoptive transfer of Tregs relieved lipid metabolic disorder, oxidative stress, inflammation, and, consequently, ameliorated the alcoholic fatty liver. Macrophages are a dominant source of inflammation in ALD. Aberrant macrophage activation and cytokine production were activated during chronic alcohol consumption, but were significantly inhibited after Treg transfer. In vitro, macrophages were co-activated by alcohol and lipopolysaccharide to mimic a condition for alcoholic liver microenvironment. Tregs suppressed monocyte chemoattractant protein-1 and TNF-α production from these macrophages. However, such effects of Tregs were remarkably neutralized when interleukin (IL)-10 was blocked. Altogether, our data uncover a novel role of Tregs in restoring liver lipid metabolism in ALD, which partially relies on IL-10-mediated suppression of hepatic pro-inflammatory macrophages.

Management of Diabetes Mellitus in Patients with Chronic Liver Diseases

Diabetes mellitus (DM) is a common chronic disease affecting humans globally. During the last few years, the incidence of diabetes has increased and has received more attention. In addition to growing DM populations, DM complications are involving injuries to more organs, such as the heart and cerebral vessel damage. DM complications can reduce quality of life and shorten life spans and eventually also impede social and economic development. Therefore, effective measures to curb the occurrence and development of diabetes assist in improving patients' quality of life, delay the progression of DM in the population, and ease a social burden. The liver is regarded as an important link in the management and control of DM, including the alleviation of glucose metabolism and lipid metabolism and others via glucose storage and endogenous glucose generation from glycogen stored in the liver. Liver cirrhosis is a very common chronic disease, which often lowers the quality of life and decreases life expectancy. According to a growing body of research, diabetes shows a close correlation with hepatitis, liver cirrhosis, and liver cancer. Moreover, coexistence of liver complications would accelerate the deterioration of patients with diabetes. Liver cirrhosis and diabetes influence each other. Thus, in addition to pharmacological treatments and lifestyle interventions, effective control of cirrhosis might assist in a better management of diabetes. When it comes to different etiologies of liver cirrhosis, different therapeutic methods, such as antiviral treatment, may be more effective. Effective control of cirrhosis might be a strategy for better management of diabetes.

Mitochondrial Stasis Reveals p62-Mediated Ubiquitination in Parkin-Independent Mitophagy and Mitigates Nonalcoholic Fatty Liver Disease

It is unknown what occurs if both mitochondrial division and fusion are completely blocked. Here, we introduced mitochondrial stasis by deleting two dynamin-related GTPases for division (Drp1) and fusion (Opa1) in livers. Mitochondrial stasis rescues liver damage and hypotrophy caused by the single knockout (KO). At the cellular level, mitochondrial stasis re-establishes mitochondrial size and rescues mitophagy defects caused by division deficiency. Using Drp1KO livers, we found that the autophagy adaptor protein p62/sequestosome-1-which is thought to function downstream of ubiquitination-promotes mitochondrial ubiquitination. p62 recruits two subunits of a cullin-RING ubiquitin E3 ligase complex, Keap1 and Rbx1, to mitochondria. Resembling Drp1KO, diet-induced nonalcoholic fatty livers enlarge mitochondria and accumulate mitophagy intermediates. Resembling Drp1Opa1KO, Opa1KO rescues liver damage in this disease model. Our data provide a new concept that mitochondrial stasis leads the spatial dimension of mitochondria to a stationary equilibrium and a new mechanism for mitochondrial ubiquitination in mitophagy.

Non-alcoholic fatty liver disease: an update on diagnosis

Background and aim

The non-alcoholic fatty liver disease (NAFLD) and its sub-entity, the non-alcoholic steatohepatitis (NASH) represent a field of a tremendous progress in recent years. Clinicians need to remain updated with new data on pathogenesis and therapy. The present mini review aims to present some new scientific reports on the diagnosis of NAFLD and NASH for clinical practitioners.

Methods

A systematic literature search of the main international databases was performed. We looked for seminal and innovative papers published in main international languages. A narrative review of the topic was consequently written.

Results

This review describes new data on the diagnosis of NAFLD including NASH. Liver punction biopsy remains the gold standard. However many patients and clinicians prefer to use noninvasive methods. We present the serological tests and the imaging methods used to diagnose inflammation and fibrosis occurring in NAFLD and NASH.

Conclusions

NAFLD-NASH are multifaceted entities that have to be diagnosed and treated by skilled and informed practitioners.

The Hippo-YAP Pathway Regulates 3D Organ Formation and Homeostasis

The vertebrate body shape is formed by the specific sizes and shapes of its resident tissues and organs, whose alignments are essential for proper functioning. To maintain tissue and organ shape, and thereby function, it is necessary to remove senescent, transformed, and/or damaged cells, which impair function and can lead to tumorigenesis. However, the molecular mechanisms underlying three-dimensional (3D) organ formation and homeostasis are not fully clear. Yes-associated protein (YAP) is a transcriptional co-activator that is involved in organ size control and tumorigenesis. Recently, we reported that YAP is essential for proper 3D body shape through regulation of cell tension by using a unique medaka fish mutant, hirame (hir). In Madin&ndash;Darby canine kidney (MDCK) epithelial cells, active YAP-transformed cells are eliminated apically when surrounded by normal cells. Furthermore, in a mosaic mouse model, active YAP-expressing damaged hepatocytes undergo apoptosis and are eliminated from the liver. Thus, YAP functions in quantitative and quality control in organogenesis. In this review, we describe the various roles of YAP in vertebrates, including in the initiation of liver cancer.

Liver function and dysfunction - a unique window into the physiological reach of ER stress and the unfolded protein response

The unfolded protein response (UPR) improves endoplasmic reticulum (ER) protein folding in order to alleviate stress. Yet it is becoming increasingly clear that the UPR regulates processes well beyond those directly involved in protein folding, in some cases by mechanisms that fall outside the realm of canonical UPR signaling. These pathways are highly specific from one cell type to another, implying that ER stress signaling affects each tissue in a unique way. Perhaps nowhere is this more evident than in the liver, which-beyond being a highly secretory tissue-is a key regulator of peripheral metabolism and a uniquely proliferative organ upon damage. The liver provides a powerful model system for exploring how and why the UPR extends its reach into physiological processes that occur outside the ER, and how ER stress contributes to the many systemic diseases that involve liver dysfunction. This review will highlight the ways in which the study of ER stress in the liver has expanded the view of the UPR to a response that is a key guardian of cellular homeostasis outside of just the narrow realm of ER protein folding.

YAP determines the cell fate of injured mouse hepatocytes in vivo

The presence of senescent, transformed or damaged cells can impair tissue function or lead to tumorigenesis; therefore, organisms have evolved quality control mechanisms to eliminate them. Here, we show that YAP activation induced by inactivation of the Hippo pathway specifically in damaged hepatocytes promotes their selective elimination by using in vivo mosaic analysis in mouse liver. These damaged hepatocytes migrate into the hepatic sinusoids, undergo apoptosis and are engulfed by Kupffer cells. In contrast, YAP activation in undamaged hepatocytes leads to proliferation. Cellular stresses such as ethanol that damage both liver sinusoidal endothelial cells and hepatocytes switch cell fate from proliferation to migration/apoptosis in the presence of activated YAP. This involves the activation of CDC42 and Rac that regulate cell migration. Thus, we suggest that YAP acts as a stress sensor that induces elimination of injured cells to maintain tissue and organ homeostasis.

Senescent and injured cells affect tissue functions and can drive tumorigenesis. Thus, efficient elimination of these cells is pivotal for tissue integrity. Here Miyamura et al. show that YAP acts as a cellular stress sensor and promotes the elimination of damaged cells to maintain tissue homeostasis.

Caspase-cleaved keratin-18 fragments increase during alcohol withdrawal and predict liver-related death in patients with alcoholic liver disease

Noninvasive assessment of disease activity in patients with nonalcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD) is still unsettled, but essential for the evaluation of disease progression. We here studied the association of total (M65) and caspase-cleaved (M30) serum keratin-18 fragments (n = 204) with histological parameters (n = 106) in heavy drinkers primarily admitted for alcohol withdrawal before and after alcohol detoxification. An age-, sex-, and fibrosis-stage matched NAFLD cohort (n = 30) was used for comparison. The prognostic value of M30 and M65 levels were assessed in an additional prospectively followed-up cohort of 230 patients with alcoholic cirrhosis (AC) using competing risk analyses. Among the histological parameters, both M30/65 correlated significantly and better than any other serum marker with apoptosis and liver damage, such as ballooning (r = 0.65; P < 0.001), followed by lobular inflammation (0.48; P < 0.001), steatosis (0.46; P < 0.001), but less with fibrosis (0.24; P < 0.001). Area under the receiver operating characteristics curves to detect ballooning, steatosis, or steatohepatitis (SH) were slightly better for M30 (P < 0.005). Optimal M30 cut-off values for mild and severe ballooning were 330 and 420 U/L, and 290 and 330 U/L for SH grades 1 and 2. No significant differences of M30/65 were found between the matched NAFLD and ALD cohort. In contrast to aspartate-amino-transferase and M65, M30 levels increased significantly from 391 to 518 U/L during alcohol detoxification. Moreover, levels of M30 and M65 predicted non-hepatocellular carcinoma liver-related mortality in patients with AC during a mean observation interval of 67.2 months.

CONCLUSION

Our data suggest M30 as highly specific marker of liver apoptosis both in ALD and NAFLD. In addition, hepatocellular apoptosis, as determined by M30 levels, occurs during alcohol withdrawal, and survival data point toward a novel underestimated role of apoptosis in patients with ALD. (Hepatology 2017;66:96-107).

Role of nonalcoholic fatty liver disease as risk factor for drug-induced hepatotoxicity

BACKGROUND

Obesity is often associated with nonalcoholic fatty liver disease (NAFLD), which refers to a large spectrum of hepatic lesions including fatty liver, nonalcoholic steatohepatitis (NASH) and cirrhosis. Different investigations showed or suggested that obesity and NAFLD are able to increase the risk of hepatotoxicity of different drugs. Some of these drugs could induce more frequently an acute hepatitis in obese individuals whereas others could worsen pre-existing NAFLD.

AIM

The main objective of the present review was to collect the available information regarding the role of NAFLD as risk factor for drug-induced hepatotoxicity. For this purpose, we performed a data-mining analysis using different queries including drug-induced liver injury (or DILI), drug-induced hepatotoxicity, fatty liver, nonalcoholic fatty liver disease (or NAFLD), steatosis and obesity. The main data from the collected articles are reported in this review and when available, some pathophysiological hypotheses are put forward.

RELEVANCE FOR PATIENTS

Drugs that could pose a potential risk in obese patients include compounds belonging to different pharmacological classes such as acetaminophen, halothane, methotrexate, rosiglitazone, stavudine and tamoxifen. For some of these drugs, experimental investigations in obese rodents confirmed the clinical observations and unveiled different pathophysiological mechanisms which could explain why these pharmaceuticals are particularly hepatotoxic in obesity and NAFLD. Other drugs such as pentoxifylline, phenobarbital and omeprazole might also pose a risk but more investigations are required to determine whether this risk is significant or not. Because obese people often take several drugs for the treatment of different obesity-related diseases such as type 2 diabetes, hyperlipidemia and coronary heart disease, it is urgent to identify the main pharmaceuticals that can cause acute hepatitis on a fatty liver background or induce NAFLD worsening.

Alcohol, microbiome, life style influence alcohol and non-alcoholic organ damage

This paper is based upon the "8th Charles Lieber's Satellite Symposium" organized by Manuela G. Neuman at the Research Society on Alcoholism Annual Meeting, on June 25, 2016 at New Orleans, Louisiana, USA. The integrative symposium investigated different aspects of alcohol-induced liver disease (ALD) as well as non-alcohol-induced liver disease (NAFLD) and possible repair. We revealed the basic aspects of alcohol metabolism that may be responsible for the development of liver disease as well as the factors that determine the amount, frequency and which type of alcohol misuse leads to liver and gastrointestinal diseases. We aimed to (1) describe the immuno-pathology of ALD, (2) examine the role of genetics in the development of alcoholic hepatitis (ASH) and NAFLD, (3) propose diagnostic markers of ASH and non-alcoholic steatohepatitis (NASH), (4) examine age and ethnic differences as well as analyze the validity of some models, (5) develop common research tools and biomarkers to study alcohol-induced effects, 6) examine the role of alcohol in oral health and colon and gastrointestinal cancer and (7) focus on factors that aggravate the severity of organ-damage. The present review includes pre-clinical, translational and clinical research that characterizes ALD and NAFLD. Strong clinical and experimental evidence lead to recognition of the key toxic role of alcohol in the pathogenesis of ALD with simple fatty infiltrations and chronic alcoholic hepatitis with hepatic fibrosis or cirrhosis. These latter stages may also be associated with a number of cellular and histological changes, including the presence of Mallory's hyaline, megamitochondria, or perivenular and perisinusoidal fibrosis. Genetic polymorphisms of ethanol metabolizing enzymes and cytochrome p450 (CYP) 2E1 activation may change the severity of ASH and NASH. Other risk factors such as its co-morbidities with chronic viral hepatitis in the presence or absence of human deficiency virus were discussed. Dysregulation of metabolism, as a result of ethanol exposure, in the intestine leads to colon carcinogenesis. The hepatotoxic effects of ethanol undermine the contribution of malnutrition to the liver injury. Dietary interventions such as micro and macronutrients, as well as changes to the microbiota have been suggested. The clinical aspects of NASH, as part of the metabolic syndrome in the aging population, have been presented. The symposium addressed mechanisms and biomarkers of alcohol induced damage to different organs, as well as the role of the microbiome in this dialog. The microbiota regulates and acts as a key element in harmonizing immune responses at intestinal mucosal surfaces. It is known that microbiota is an inducer of proinflammatory T helper 17 cells and regulatory T cells in the intestine. The signals at the sites of inflammation mediate recruitment and differentiation in order to remove inflammatory inducers and promote tissue homeostasis restoration. The change in the intestinal microbiota also influences the change in obesity and regresses the liver steatosis. Evidence on the positive role of moderate alcohol consumption on heart and metabolic diseases as well on reducing steatosis have been looked up. Moreover nutrition as a therapeutic intervention in alcoholic liver disease has been discussed. In addition to the original data, we searched the literature (2008-2016) for the latest publication on the described subjects. In order to obtain the updated data we used the usual engines (Pub Med and Google Scholar). The intention of the eighth symposia was to advance the international profile of the biological research on alcoholism. We also wish to further our mission of leading the forum to progress the science and practice of translational research in alcoholism.

Glycosylation site occupancy in health, congenital disorder of glycosylation and fatty liver disease

Glycosylation is an integral part in health and disease, as emphasized by the growing number of identified glycosylation defects. In humans, proteins are modified with a diverse range of glycoforms synthesized in complex biosynthetic pathways. Glycosylation disorders have been described in congenital disorders of glycosylation (CDG) as well as in acquired disease conditions such and non-alcoholic fatty liver disease (NAFLD). A hallmark in a subset of CDG cases is the reduced glycosylation site occupancy of asparagine-linked glycans. Using an optimized method protocol, we determined the glycosylation site occupancy from four proteins of hepatic and lymphatic origin from CDG and NAFLD patients. We found variable degrees of site occupancy, depending on the tissue of origin and the disease condition. In CDG glycosylation sites of IgG2 and IgA1 were occupied to normal levels. In NAFLD haptoglobin and transferrin glycosylation sites were hyper-glycosylated, a property qualifying for its use as a potential biomarker. Furthermore, we observed, that glycosylation sites of liver-originating transferrin and haptoglobin are differentially occupied under physiological conditions, a further instance not noticed in serum proteins to date. Our findings suggest the use of serum protein hyperglycosylation as a biomarker for early stages of NAFLD.

Chronic Glutathione Depletion Confers Protection against Alcohol-induced Steatosis: Implication for Redox Activation of AMP-activated Protein Kinase Pathway

The pathogenesis of alcoholic liver disease (ALD) is not well established. However, oxidative stress and associated decreases in levels of glutathione (GSH) are known to play a central role in ALD. The present study examines the effect of GSH deficiency on alcohol-induced liver steatosis in Gclm knockout (KO) mice that constitutively have ≈15% normal hepatic levels of GSH. Following chronic (6 week) feeding with an ethanol-containing liquid diet, the Gclm KO mice were unexpectedly found to be protected against steatosis despite showing increased oxidative stress (as reflected in elevated levels of CYP2E1 and protein carbonyls). Gclm KO mice also exhibit constitutive activation of liver AMP-activated protein kinase (AMPK) pathway and nuclear factor-erythroid 2–related factor 2 target genes, and show enhanced ethanol clearance, altered hepatic lipid profiles in favor of increased levels of polyunsaturated fatty acids and concordant changes in expression of genes associated with lipogenesis and fatty acid oxidation. In summary, our data implicate a novel mechanism protecting against liver steatosis via an oxidative stress adaptive response that activates the AMPK pathway. We propose redox activation of the AMPK may represent a new therapeutic strategy for preventing ALD.

New treatment options for alcoholic hepatitis

The burden of alcoholic liver disease has rapidly grown in the past two decades and is expected to increase further in the coming years. Alcoholic hepatitis, the most florid presentation of alcoholic liver disease, continues to have high morbidity and mortality, with significant financial and healthcare burden with limited treatment options. Steroids remain the current standard of care in severe alcoholic hepatitis in carefully selected patients. No specific treatments are available for those patients who are steroid ineligible, intolerant or unresponsive. Liver transplant has shown good short-term outcome; however, feasibility, ethical and economic concerns remain. Modification of gut microbiota composition and their products, such as lipopolysaccharide, nutritional interventions, immune modulation, increasing steroid sensitivity, genetic polymorphism and epigenetic modification of alcohol induced liver damage, augmenting hepatic regeneration using GCSF are potential therapeutic avenues in steroid non-responsive/ineligible patients. With better understanding of the pathophysiology, using “Omics” platforms, newer options for patients with alcoholic hepatitis are expected soon.

Ethnicity matters: A Systematic Review and Meta-Analysis of the Non-Linear Relationship Between Alcohol Consumption and Prevalence and Incidence of Hepatic Steatosis

BACKGROUND

Fatty liver (hepatic steatosis) is one of the most common diseases globally, with increasing prevalence. The role of alcohol consumption in the development of hepatic steatosis has not been systematically examined.

METHODS

We searched Medline, Embase, and ProQuest Dissertations & Theses Global for original data on the relationship between alcohol consumption and hepatic steatosis measured by non-invasive imagery, excluding studies conducted in participants <18years, or subgroups related to viral and drug-induced liver disease. We identified 18 articles reporting adjusted data (Japan=11, other high-income countries=7). Random-effect categorical meta-analyses (<20g/day pure alcohol consumption vs non-drinkers) and dose-response meta-analyses for the whole range of alcohol consumption were conducted.

RESULTS

In total, 99,370 participants and 25,662 cases of hepatic steatosis were included. In Japan, low alcohol consumption was consistently associated with substantially reduced incidence and prevalence of hepatic steatosis compared to non-drinkers (RR for <20g pure alcohol/day=0.75, 95% CI: 0.71-0.79, I(2)=0%). No overall association was found in other countries (RR=1.05, 95% CI: 0.86-1.30, I(2)=84%). Dose-response analyses in Japan (up to 80g/day) showed an inverse relationship in men and a J-shape in women.

CONCLUSIONS

Alcohol consumption showed a complex association with hepatic steatosis with substantial differences by ethnicity and sex. Low alcohol consumption was beneficial in Japan with good epidemiological evidence, whereas there was no association in other countries. However, heterogeneity was large in countries other than Japan. More and higher quality research in diverse ethnic populations is needed to further clarify this relationship.

Mechanisms of non-alcoholic fatty liver disease and its correlation with chronic stress

With the increase in the incidence of non-alcoholic fatty liver disease (NAFLD), the distributions of area and age have gradually expanded, and it has become a hot topic in the field of medical and scientific research. Previous studies often attributed the reason of NAFLD to unhealthy diet and lifestyle. However, recent studies have shown that chronic stress is one of the main factors for the development of NAFLD. In this paper, we present the latest research achievements on the mechanism of NAFLD caused by chronic stress, with an aim to provide a theoretical basis for the prevention and treatment of NAFLD.

Altered Bile Acid Metabolome in Patients with Nonalcoholic Steatohepatitis

BACKGROUND AND AIMS

The prevalence of nonalcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) is increasing at an alarming rate. The role of bile acids in the development and progression of NAFLD to NASH and cirrhosis is poorly understood. This study aimed to quantify the bile acid metabolome in healthy subjects and patients with non-cirrhotic NASH under fasting conditions and after a standardized meal.

METHODS

Liquid chromatography tandem mass spectroscopy was used to quantify 30 serum and 16 urinary bile acids from 15 healthy volunteers and 7 patients with biopsy-confirmed NASH. Bile acid concentrations were measured at two fasting and four post-prandial time points following a high-fat meal to induce gallbladder contraction and bile acid reabsorption from the intestine.

RESULTS

Patients with NASH had significantly higher total serum bile acid concentrations than healthy subjects under fasting conditions (2.2- to 2.4-fold increase in NASH; NASH 2595-3549 µM and healthy 1171-1458 µM) and at all post-prandial time points (1.7- to 2.2-fold increase in NASH; NASH 4444-5898 µM and healthy 2634-2829 µM). These changes were driven by increased taurine- and glycine-conjugated primary and secondary bile acids. Patients with NASH exhibited greater variability in their fasting and post-prandial bile acid profile.

CONCLUSIONS

Results indicate that patients with NASH have higher fasting and post-prandial exposure to bile acids, including the more hydrophobic and cytotoxic secondary species. Increased bile acid exposure may be involved in liver injury and the pathogenesis of NAFLD and NASH.

Alcoholic Liver Disease: Role of Cytokines

The present review spans a broad spectrum of topics dealing with alcoholic liver disease (ALD), including clinical and translational research. It focuses on the role of the immune system and the signaling pathways of cytokines in the pathogenesis of ALD. An additional factor that contributes to the pathogenesis of ALD is lipopolysaccharide (LPS), which plays a central role in the induction of steatosis, inflammation, and fibrosis in the liver. LPS derived from the intestinal microbiota enters the portal circulation, and is recognized by macrophages (Kupffer cells) and hepatocytes. In individuals with ALD, excessive levels of LPS in the liver affect immune, parenchymal, and non-immune cells, which in turn release various inflammatory cytokines and recruit neutrophils and other inflammatory cells. In this review, we elucidate the mechanisms by which alcohol contributes to the activation of Kupffer cells and the inflammatory cascade. The role of the stellate cells in fibrogenesis is also discussed.

Review of matrix-assisted laser desorption ionization-imaging mass spectrometry for lipid biochemical histopathology

Matrix-Assisted Laser Desorption Ionization-Imaging Mass Spectrometry (MALDI-IMS) is a rapidly evolving method used for the in situ visualization and localization of molecules such as drugs, lipids, peptides, and proteins in tissue sections. Therefore, molecules such as lipids, for which antibodies and other convenient detection reagents do not exist, can be detected, quantified, and correlated with histopathology and disease mechanisms. Furthermore, MALDI-IMS has the potential to enhance our understanding of disease pathogenesis through the use of "biochemical histopathology". Herein, we review the underlying concepts, basic methods, and practical applications of MALDI-IMS, including post-processing steps such as data analysis and identification of molecules. The potential utility of MALDI-IMS as a companion diagnostic aid for lipid-related pathological states is discussed.

Biomolecules and Biomarkers Used in Diagnosis of Alcohol Drinking and in Monitoring Therapeutic Interventions

BACKGROUND

The quantitative, measurable detection of drinking is important for the successful treatment of alcohol misuse in transplantation of patients with alcohol disorders, people living with human immunodeficiency virus that need to adhere to medication, and special occupational hazard offenders, many of whom continually deny drinking. Their initial misconduct usually leads to medical problems associated with drinking, impulsive social behavior, and drunk driving. The accurate identification of alcohol consumption via biochemical tests contributes significantly to the monitoring of drinking behavior.

METHODS

A systematic review of the current methods used to measure biomarkers of alcohol consumption was conducted using PubMed and Google Scholar databases (2010-2015). The names of the tests have been identified. The methods and publications that correlate between the social instruments and the biochemical tests were further investigated. There is a clear need for assays standardization to ensure the use of these biochemical tests as routine biomarkers.

FINDINGS

Alcohol ingestion can be measured using a breath test. Because alcohol is rapidly eliminated from the circulation, the time for detection by this analysis is in the range of hours. Alcohol consumption can alternatively be detected by direct measurement of ethanol concentration in blood or urine. Several markers have been proposed to extend the interval and sensitivities of detection, including ethyl glucuronide and ethyl sulfate in urine, phosphatidylethanol in blood, and ethyl glucuronide and fatty acid ethyl esters in hair, among others. Moreover, there is a need to correlate the indirect biomarker carbohydrate deficient transferrin, which reflects longer lasting consumption of higher amounts of alcohol, with serum γ-glutamyl transpeptidase, another long term indirect biomarker that is routinely used and standardized in laboratory medicine.

Translational Implications of the Alcohol-Metabolizing Enzymes, Including Cytochrome P450-2E1, in Alcoholic and Nonalcoholic Liver Disease

Fat accumulation (hepatic steatosis) in alcoholic and nonalcoholic fatty liver disease is a potentially pathologic condition which can progress to steatohepatitis (inflammation), fibrosis, cirrhosis, and carcinogenesis. Many clinically used drugs or some alternative medicine compounds are also known to cause drug-induced liver injury, which can further lead to fulminant liver failure and acute deaths in extreme cases. During liver disease process, certain cytochromes P450 such as the ethanol-inducible cytochrome P450-2E1 (CYP2E1) and CYP4A isozymes can be induced and/or activated by alcohol and/or high-fat diets and pathophysiological conditions such as fasting, obesity, and diabetes. Activation of these P450 isozymes, involved in the metabolism of ethanol, fatty acids, and various drugs, can produce reactive oxygen/nitrogen species directly and/or indirectly, contributing to oxidative modifications of DNA/RNA, proteins and lipids. In addition, aldehyde dehydrogenases including the mitochondrial low Km aldehyde dehydrogenase-2 (ALDH2), responsible for the metabolism of acetaldehyde and lipid aldehydes, can be inactivated by various hepatotoxic agents. These highly reactive acetaldehyde and lipid peroxides, accumulated due to ALDH2 suppression, can interact with cellular macromolecules DNA/RNA, lipids, and proteins, leading to suppression of their normal function, contributing to DNA mutations, endoplasmic reticulum stress, mitochondrial dysfunction, steatosis, and cell death. In this chapter, we specifically review the roles of the alcohol-metabolizing enzymes including the alcohol dehydrogenase, ALDH2, CYP2E1, and other enzymes in promoting liver disease. We also discuss translational research opportunities with natural and/or synthetic antioxidants, which can prevent or delay the onset of inflammation and liver disease.

Transgenic mice and metabolomics for study of hepatic xenobiotic metabolism and toxicity

INTRODUCTION

The study of xenobiotic metabolism and toxicity has been greatly aided by the use of genetically modified mouse models and metabolomics.

AREAS COVERED

Gene knockout mice can be used to determine the enzymes responsible for the metabolism of xenobiotics in vivo and to examine the mechanisms of xenobiotic-induced toxicity. Humanized mouse models are especially important because there exist marked species differences in the xenobiotic-metabolizing enzymes and the nuclear receptors that regulate these enzymes. Humanized mice expressing CYPs and nuclear receptors including the pregnane X receptor, the major regulator of xenobiotic metabolism and transport were produced. With genetically modified mouse models, metabolomics can determine the metabolic map of many xenobiotics with a level of sensitivity that allows the discovery of even minor metabolites. This technology can be used for determining the mechanism of xenobiotic toxicity and to find early biomarkers for toxicity.

EXPERT OPINION

Metabolomics and genetically modified mouse models can be used for the study of xenobiotic metabolism and toxicity by: i) comparison of the metabolomics profiles between wild-type and genetically modified mice, and searching for genotype-dependent endogenous metabolites; ii) searching for and elucidating metabolites derived from xenobiotics; and iii) discovery of specific alterations of endogenous compounds induced by xenobiotics-induced toxicity.

Hepatitis C, innate immunity and alcohol: friends or foes?

Hepatitis C and alcohol are the most widespread causes of liver disease worldwide. Approximately 80% of patients with a history of hepatitis C and alcohol abuse develop chronic liver injury. Alcohol consumption in hepatitis C virus (HCV)-infected patients exacerbates liver disease leading to rapid progression of fibrosis, cirrhosis and even hepatocellular carcinoma. Hepatocytes are the main sites of HCV-infection and ethanol metabolism, both of which generate oxidative stress. Oxidative stress levels affect HCV replication and innate immunity, resulting in a greater susceptibility for HCV-infection and virus spread in the alcoholic patients. In this review paper, we analyze the effects of ethanol metabolism and other factors on HCV replication. In addition, we illustrate the mechanisms of how HCV hijacks innate immunity and how ethanol exposure regulates this process. We also clarify the effects of HCV and ethanol metabolism on interferon signaling-a crucial point for activation of anti-viral genes to protect cells from virus-and the role that HCV- and ethanol-induced impairments play in adaptive immunity which is necessary for recognition of virally-infected hepatocytes. In conclusion, ethanol exposure potentiates the suppressive effects of HCV on innate immunity, which activates viral spread in the liver and finally, leads to impairments in adaptive immunity. The dysregulation of immune response results in impaired elimination of HCV-infected cells, viral persistence, progressive liver damage and establishment of chronic infection that worsens the outcomes of chronic hepatitis C in alcoholic patients.

Nonmedicinal interventions in nonalcoholic fatty liver disease

Unhealthy diet and lack of physical exercise are responsible for fat accumulation in the liver, which may lead to liver disease. Histologically, the severity of the disease has two stages: nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). NAFLD is defined by the presence of steatosis with no evidence of cellular injury such as hepatocyte ballooning. NASH is a distinct entity from NAFLD, and is characterized by the presence of inflammation with hepatocytes damage, with or without fibrosis. While several therapeutic strategies have been proposed to improve this condition, the present review aims to discuss nonmedicinal interventions used to reduce liver involvement or to prevent the disease altogether. The authors investigated dietary patterns and vitamin deficiencies associated with NAFLD, and their role in enhancing disease severity. Additionally, they reviewed the role of exercise and the use of interventions, such as as intragastric balloon and bariatric surgery, for improving disease progression. The authors propose monitoring disease progression or repair by following changes in cytoadipokine levels.