Alcoholic liver disease: Clinical and translational research

Mitochondrial dysfunction: A promising therapeutic target for liver diseases

The liver is an important metabolic and detoxification organ and hence demands a large amount of energy, which is mainly produced by the mitochondria. Liver tissues of patients with alcohol-related or non-alcohol-related liver diseases contain ultrastructural mitochondrial lesions, mitochondrial DNA damage, disturbed mitochondrial dynamics, and compromised ATP production. Overproduction of mitochondrial reactive oxygen species induces oxidative damage to mitochondrial proteins and mitochondrial DNA, decreases mitochondrial membrane potential, triggers hepatocyte inflammation, and promotes programmed cell death, all of which impair liver function. Mitochondrial DNA may be a potential novel non-invasive biomarker of the risk of progression to liver cirrhosis and hepatocellular carcinoma in patients infected with the hepatitis B virus. We herein present a review of the mechanisms of mitochondrial dysfunction in the development of acute liver injury and chronic liver diseases, such as hepatocellular carcinoma, viral hepatitis, drug-induced liver injury, alcoholic liver disease, and non-alcoholic fatty liver disease. This review also discusses mitochondrion-centric therapies for treating liver diseases.

ADH1B, ADH1B/C and CYP2E1 Gene Polymorphism and the Risk of Fetal Alcohol Spectrum Disorder

Increasing alcohol consumption by women of childbearing age contributes to more frequent cases of fetal alcohol spectrum disorder. The cause of the syndrome is fetal alcohol exposure, particularly what is referred to as high prenatal alcohol exposure. Low metabolic activity of fetal enzymes shifts the burden of ethanol removal to maternal metabolism. One of the factors influencing the pathogenesis of FASD is the genetic background. It can determine the rate of elimination of ethanol, thus increasing or decreasing the time of fetal exposure to ethanol and also decreasing its concentration. Genetic polymorphisms could potentially play a significant role in these processes. In the present study, we considered three polymorphisms of genes implicated in the synthesis of enzymes involved in ethanol metabolism, i.e., ADH1b (rs1229984), ADH1b/c (rs1789891), and CYP2E1 (rs3813867). The studied group consisted of 303 children and 251 mothers. Both mothers' and children's genotypes were considered in our analysis. There were no statistically significant differences between the respective groups of genotypes of the studied polymorphisms. However, the genetic background of FASD is still elusive.

Immune dysregulation and pathophysiology of alcohol consumption and alcoholic liver disease

Alcoholic liver disease (ALD) is a clinical-pathologic entity caused by the chronic excessive consumption of alcohol. The disease includes a broad spectrum of anomalies at the cellular and tissual level that can cause acute-on-chronic (alcoholic hepatitis) or chronic (fibrosis, cirrhosis, hepatocellular cancer) injury, having a great impact on morbidity and mortality worldwide. Alcohol is metabolized mainly in the liver. During alcohol metabolism, toxic metabolites, such as acetaldehyde and oxygen reactive species, are produced. At the intestinal level, alcohol consumption can cause dysbiosis and alter intestinal permeability, promoting the translocation of bacterial products and causing the production of inflammatory cytokines in the liver, perpetuating local inflammation during the progression of ALD. Different study groups have reported systemic inflammatory response disturbances, but reports containing a compendium of the cytokines and cells involved in the pathophysiology of the disease, from the early stages, are difficult to find. In the present review article, the role of the inflammatory mediators involved in ALD progression are described, from risky patterns of alcohol consumption to advanced stages of the disease, with the aim of understanding the involvement of immune dysregulation in the pathophysiology of ALD.

The effects of Gentiana dahurica Fisch on alcoholic liver disease revealed by RNA sequencing

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Gentiana dahurica Fisch (called Qin-Jiao in China), a traditional Chinese medicine, is used in China to treat alcoholic liver disease (ALD), but there has been no scientific report on the treatment of ALD.

AIM OF THE STUDY

To investigate the therapeutic effects of Gentiana dahurica Fisch ethanol extract (GDEE) on ALD and to reveal its possible mechanism of action using RNA sequencing.

MATERIALS AND METHODS

The model of ALD was established by continuous gavage with alcohol in mice, and GDEE was used to treat ALD. Pathological observation (HE staining, oil red O staining) and biochemical indicators were performed to evaluate liver tissue lesions and efficacy of GDEE. RNA sequencing analysis of liver tissues was carried out to elucidate the pathogenesis of ALD and the mechanism of hepatoprotective effect by GDEE. The RNA sequencing results were verified by detecting mRNA and protein expressions of acetyl coenzyme A carboxylase α (Acacα), fatty acid synthase (Fasn) and carnitine palmitoyltransferase 1A (Cpt1a) by quantitative real-time polymerase chain reaction (PCR) and Western blot.

RESULTS

Measurements of biochemical parameters showed that GDEE could inhibit the increased transaminase activities in the serum and lipid levels in the liver caused by alcohol. It was observed that GDEE could alleviate fatty degeneration, edema and cell necrosis caused by alcohol in the liver tissue. RNA sequencing analysis of liver tissues found that 719 genes and 1137 genes were significantly changed by alcohol and GDEE, respectively. GDEE reversed most of the changes in triglycerides synthesis-related genes up-regulated by alcohol. GDEE up-regulated most of the genes involved in the fatty acid degradation in ALD mice, while alcohol had little effect on them. In addition, GDEE suppressed most of the genes involved in cholesterol synthesis that were up-regulated by alcohol. GDEE up-regulated genes related to bile acid synthesis in ALD mice, and down-regulated genes related to bile acid reabsorption, while alcohol had no significant effect on genes related to bile acid metabolism. In the validation experiments, the Acacα, Fasn and Cpt1a expressions quantified by real-time PCR and Western blot were consistent with the RNA sequencing results.

CONCLUSIONS

GDEE can alleviate liver damage and steatosis in ALD mice, and its mechanism of action may be related to the process of regulating triglycerides and cholesterol.

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.

Oxidative Stress-A Key Player in the Course of Alcohol-Related Liver Disease

Oxidative stress is known to be an inseparable factor involved in the presentation of liver disorders. Free radicals interfere with DNA, proteins, and lipids, which are crucial in liver metabolism, changing their expression and biological functions. Additionally, oxidative stress modifies the function of micro-RNAs, impairing the metabolism of hepatocytes. Free radicals have also been proven to influence the function of certain transcriptional factors and to alter the cell cycle. The pathological appearance of alcohol-related liver disease (ALD) constitutes an ideal example of harmful effects due to the redox state. Finally, ethanol-induced toxicity and overproduction of free radicals provoke irreversible changes within liver parenchyma. Understanding the underlying mechanisms associated with the redox state in the course of ALD creates new possibilities of treatment for patients. The future of hepatology may become directly dependent on the effective action against reactive oxygen species. This review summarizes current data on the redox state in the natural history of ALD, highlighting the newest reports on this topic.

Hepatic stellate cell-derived exosomes modulate macrophage inflammatory response

BACKGROUND

Hepatic stellate cell (HSC) differentiation/activation is central to liver fibrosis and is innately linked to the immune response to liver injury. Exosomes (EXOs) are important means of communication between cell populations. This study sought to characterize EXO release from HSCs and the effect of HSC-EXOs on macrophage cytokine release/function.

METHODS

Liver from a rat fibrosis model was analyzed for EXO expression and localization. Quiescent and culture-activated rat and mouse HSCs and activated human HSCs were analyzed for microRNA expression. Mouse, rat, and human HSCs were culture-activated and EXOs purified from culture medium prior to addition to macrophages, and interleukin-6 (IL-6) and tumor necrosis factor-α (TNFα) mRNA and protein measured. The effect of activated HSC-EXOs on macrophage migration was assayed.

RESULTS

Activation of rat HSCs led to increased EXO production in vivo, an effect mirrored by in vitro rat HSC culture-activation. Culture activation of mouse and rat HSCs led to altered EXO microRNA profiles, with a similar microRNA profile detected in activated human HSCs. Addition of activated HSC-EXOs to macrophages stimulated IL-6 and TNFα mRNA expression and protein secretion in mouse and human macrophages, but not for rat HSC-EXO-macrophages. Addition of human EXOs to macrophages stimulated migration, effects mirrored by the direct addition of rhIL-6 and rhTNFα.

CONCLUSIONS

HSC-EXOs associate with macrophages and stimulate cytokine synthesis-release and macrophage migration. Constructing a comprehensive understanding of EXO interactions between liver cell populations in the setting of inflammation/fibrosis increases the potential for developing new diagnostic/therapeutic approaches.

Non-Alcoholic Fatty Liver Disease and Cardiovascular Comorbidities: Pathophysiological Links, Diagnosis, and Therapeutic Management

Non-alcoholic fatty liver disease (NAFLD) has a growing prevalence in recent years. Its association with cardiovascular disease has been intensively studied, and certain correlations have been identified. The connection between these two entities has lately aroused interest regarding therapeutic management. In order to find the best therapeutic options, a detailed understanding of the pathophysiology that links (NAFLD) to cardiovascular comorbidities is needed. This review focuses on the pathogenic mechanisms that are behind these two diseases and on the therapeutic management available at this time.

Fatty acid binding protein-4 promotes alcohol-dependent hepatosteatosis and hepatocellular carcinoma progression

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Fatty liver disease (hepatosteatosis) is a hallmark of ALD and NAFLD.

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FABP4 is normally expressed in adipocytes and macrophages.

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ALD leads to FABP4 synthesis/release from steatotic hepatocytes.

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FABP4 stimulates hepatoma cell growth and migration.

Fatty liver disease (hepatosteatosis) is a common early pathology in alcohol-dependent and obese patients. Fatty acid binding protein-4 (FABP4) is normally expressed in adipocytes and macrophages and functions as a regulator of intracellular lipid movement/storage. This study sought to investigate hepatic FABP4 expression and function in alcoholic liver disease (ALD) and hepatocellular carcinoma (HCC). Using chronic ethanol fed mouse models and patient samples FABP4 expression was analyzed. Human HCC cells, and HCC cells transfected to express CYP2E1, were exposed to ethanol and analyzed for FABP4 expression, or exposed to rhFABP4 (in the absence/presence of ERK, p38-MAPK or JNK1/2 inhibitors) and cell proliferation and migration measured. Hepatosteatotic-ALD mouse models exhibited increased hepatic FABP4 mRNA and protein levels, with FABP4 expression confirmed in hepatocytes. In HCC cells, CYP2E1-dependent ethanol metabolism induced FABP4 expression in vitro and exogenous rhFABP4 stimulated proliferation and migration, effects abrogated by ERK and JNK1/2 inhibition. Increased FABP4 was also detected in ALD/ALD-HCC patients, but not patients with viral hepatitis/HCC. Collectively these data demonstrate ethanol metabolism induces hepatic FABP4 expression and FABP4 promotes hepatoma cell proliferation/migration. These data suggest liver-derived FABP4 may be an important paracrine-endocrine factor during hepatic foci expansion and/or hepatoma progression in the underlying setting of ALD.

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.

Biomarkers of Drug-Induced Liver Toxicity

Drug-induced liver injury (DILI) is a comprehensive phenomenon. The injury to the liver may occur as an unexpected and undesired reaction to a therapeutic dose of a drug (idiosyncratic reaction) or as an expected therapeutic effect of the direct (intrinsic) toxicity of a drug taken in a large enough dose to cause liver injury. The direct toxicity (type A) reactions represent an extension of the drug's therapeutic effect; they occur relatively frequently and are typically dose-related and frequency-of-exposure-related. By contrast, idiosyncratic reactions, or type B reactions, are unpredictable, occurring only in susceptible individuals, and are unrelated to the dose or frequency of exposure. DILI encompasses both acute and/or chronic hepatic lesions. The liver injury may be the only clinical manifestation of the adverse drug effect. Otherwise, it may be accompanied by injury to other organs, or by systemic manifestations. The liver injury may be observed in 1-8 days from taking the drug. DILI cases may result in the disapproval of a new drug or in the removal of a useful drug from the market by regulatory agencies. The purpose of this review is to provide guidance to facilitate the detection and assessment of hepatotoxicity induced by therapeutics that received market authorization. This review supports the safe and effective use of drugs by patients and guides laboratory medicine professional in determining the possible drug-induced liver damage.

Mitochondrial DNA in liver inflammation and oxidative stress

The function of liver is highly dependent on mitochondria producing ATP for biosynthetic and detoxifying properties. Accumulating evidence indicates that most hepatic disorders are characterized by profound mitochondrial dysfunction. Mitochondrial dysfunction not only exhibits mitochondrial DNA (mtDNA) damage and depletion, but also releases mtDNA. mtDNA is a closed circular molecule encoding 13 of the polypeptides of the oxidative phosphorylation system. Extensive mtDNA lesions could exacerbate mitochondrial oxidative stress and subsequently cause damage to hepatocytes. When mtDNA leaves the confines of mitochondria to the cytosolic and extracellular environment, it can act as damage-associated molecular patterns (DAMPs) to trigger the inflammatory response through the Toll-like receptor 9, inflammasomes, and stimulator of interferon genes (STING) pathways and further exacerbate hepatocellular damage and even remote organs injury. In addition, mtDNA also plays a vital role in hepatitis B virus (HBV)-related liver injury and hepatocellular carcinoma (HCC). In this review, we describe mtDNA alterations during liver injury, focusing on the mechanisms of mtDNA-mediated liver inflammation and oxidative stress injury.

The role of iron in hepatic inflammation and hepatocellular carcinoma

Iron is an essential for organisms and the liver plays a major role in its storage. In pathologic conditions, where iron absorption from the intestine or iron uptake into the hepatocytes is increased, excess iron accumulates in the hepatocytes, leading to hepatocyte injury through the production of free radicals. Iron exerts its toxicity by catalyzing the generation of reactive oxygen species (ROS). ROS causes cell injury by inducing damage to the lysosomal, cytoplasmic, nuclear and mitochondrial membranes, apoptosis through activation of the caspase cascade, and hyperoxidation of fatty chains. In this manuscript, we reviewed the articles regarding role of iron in hepatic inflammation and hepatocellular carcinoma.

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.

Resveratrol Ameliorates Experimental Alcoholic Liver Disease by Modulating Oxidative Stress

The aim of this study was to investigate the hepatoprotective effects of resveratrol in alcoholic liver disease (ALD). Alcohol was administered to healthy female rats starting from 6% (v/v) and gradually increased to 20% (v/v) by the fifth week. After 16 weeks of intervention, liver enzymes (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]) were analyzed using a chemistry analyzer, while hepatic antioxidant enzymes, oxidative stress markers, and caspase 3 activity were assessed using ELISA kits. Furthermore, hepatic CYP2E1 protein levels and mRNA levels of antioxidant and inflammation-related genes were determined using western blotting and RT-PCR, respectively. The results showed that resveratrol significantly attenuated alcohol-induced elevation of liver enzymes and improved hepatic antioxidant enzymes. Resveratrol also attenuated alcohol-induced CYP2E1 increase, oxidative stress, and apoptosis (caspase 3 activity). Moreover, genes associated with oxidative stress and inflammation were regulated by resveratrol supplementation. Taken together, the results suggested that resveratrol alleviated ALD through regulation of oxidative stress, apoptosis, and inflammation, which was mediated at the transcriptional level. The data suggests that resveratrol is a promising natural therapeutic agent against chronic ALD.

Anesthetic implications of recreational drug use

PURPOSE

As the use of recreational drugs increases, the likelihood of an anesthesiologist perioperatively encountering patients using or addicted to these drugs will also increase.

PRINCIPAL FINDINGS

Addicted patients may present for anesthetic care in a variety of circumstances in everyday elective surgeries or in acute or life-saving situations, such as emergency Cesarean delivery or trauma surgery. Therefore, it is important for anesthesiologists to know about the most common illicit drugs being used, their clinical presentation and side effects, and the anesthetic options that are beneficial or detrimental to these patients. The most frequently used illicit substances, apart from alcohol and tobacco, are cannabis, cocaine, heroin, prescription opioids, methamphetamine, and hallucinogens. When planning anesthetic care, it is important for anesthesiologists to understand the effects of these agents, including various drug interactions, to predict tolerance to some anesthetic agents, to recognize drug withdrawal signs and symptoms, and to be prepared to manage all these factors in the perioperative period.

CONCLUSIONS

For optimal patient care through the perioperative period, it is critical to obtain information about patient drug use and other associated treatment in order to construct an appropriate anesthetic plan, including specific considerations during surgery, emergence, and in the postanesthesia care unit.

Pathophysiology and Management of Alcoholic Liver Disease: Update 2016

Alcoholic liver disease (ALD) is a leading cause of cirrhosis, liver cancer, and acute and chronic liver failure and as such causes significant morbidity and mortality. While alcohol consumption is slightly decreasing in several European countries, it is rising in others and remains high in many countries around the world. The pathophysiology of ALD is still incompletely understood but relates largely to the direct toxic effects of alcohol and its main intermediate, acetaldehyde. Recently, novel putative mechanisms have been identified in systematic scans covering the entire human genome and raise new hypotheses on previously unknown pathways. The latter also identify host genetic risk factors for significant liver injury, which may help design prognostic risk scores. The diagnosis of ALD is relatively easy with a panel of well-evaluated tests and only rarely requires a liver biopsy. Treatment of ALD is difficult and grounded in abstinence as the pivotal therapeutic goal; once cirrhosis is established, treatment largely resembles that of other etiologies of advanced liver damage. Liver transplantation is a sound option for carefully selected patients with cirrhosis and alcoholic hepatitis because relapse rates are low and prognosis is comparable to other etiologies. Still, many countries are restrictive in allocating donor livers for ALD patients. Overall, few therapeutic options exist for severe ALD. However, there is good evidence of benefit for only corticosteroids in severe alcoholic hepatitis, while most other efforts are of limited efficacy. Considering the immense burden of ALD worldwide, efforts of medical professionals and industry partners to develop targeted therapies in ALF has been disappointingly low.

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.

Dysregulation of redox pathways in liver fibrosis

Reactive oxygen species are implicated in physiological signaling and cell fate decisions. In chronic liver diseases persistent and increased production of oxidative radicals drives a fibrogenic response that is a common feature of disease progression. Despite our understanding the biology of the main prooxidant enzymes, their targets, and antioxidant mechanisms in the liver, there is still lack of knowledge concerning their precise role in the pathogenesis of fibrosis. This review will examine the role of physiological redox signaling in the liver, provide an overview on recent advances in prooxidant and antioxidant pathways that are dysregulated during fibrosis, and highlight possible novel treatment targets.

Pharmacological inhibition of NOX4 ameliorates alcohol-induced liver injury in mice through improving oxidative stress and mitochondrial function

BACKGROUND

Oxidative stress plays a crucial role in the development of alcoholic liver disease (ALD), however effective pharmacological treatment for oxidative injury is still lacking. The objective of this study was to determine whether inhibition of NADPH oxidase activity could reverse alcohol-induced liver injury via protecting mitochondrial functions.

METHODS

C57BL/6J mice were pair-fed with Lieber-DeCarli control or ethanol diet for four week with or without administration with 30mg/kg/d GKT137831, a NOX4 inhibitor for the last two weeks. H4IIEC3 cells were transfected with scrambled or NOX4 shRNA. Cells were then treated with 200mM ethanol for 48h.

RESULTS

Alcohol exposure induced NOX4 expression in the liver and mitochondrial fraction. GKT137831 partially reversed alcohol-induced liver injury and elevation of serum H₂O₂. The levels of mitochondrial ROS, mitochondrial DNA, respiratory chain complex IV, and hepatic ATP were partially reversed by GKT137831 after alcohol exposure. Furthermore GKT137831 ameliorated alcohol-induced lipid accumulation and increased HNF-4α and β-oxidation enzymes. GKT137831 also decreased alcohol-induced apoptosis coupled with decreased insertion of Bax into mitochondria and decreased activation of cleaved caspase-9 and cleaved PARP. Mechanistic study shows that ethanol induced expression of NOX4 in H4IIEC3 cells. Knockdown of NOX4 caused an increased mitochondrial membrane potential, decreased mitochondrial superoxide levels, reduced number of apoptotic cells, decreased lipid accumulation, and improved ATP levels and NAD+/NADH ratio after ethanol treatment.

CONCLUSION

Pharmacological inhibition of NOX4 activity protects against alcohol-induced fat accumulation and activation of intrinsic apoptosis via improving mitochondrial function.

GENERAL SIGNIFICANCE

Pharmacological inhibition of NOX4 could be a promising treatment for ALD.