The mitochondrial biliverdin exporter ABCB10 in hepatocytes mitigates neutrophilic inflammation in alcoholic hepatitis

Acute liver failure caused by alcoholic hepatitis (AH) is only effectively treated with liver transplantation. Livers of patients with AH show a unique molecular signature characterized by defective hepatocellular redox metabolism, concurrent to hepatic infiltration of neutrophils that express myeloperoxidase (MPO) and form neutrophil extracellular traps (NETs). Exacerbated NET formation and MPO activity contribute to liver damage in mice with AH and predicts poor prognosis in AH patients. The identification of pathways that maladaptively exacerbate neutrophilic activity in liver could inform of novel therapeutic approaches to treat AH. Whether the redox defects of hepatocytes in AH directly exacerbate neutrophilic inflammation and NET formation is unclear. Here we identify that the protein content of the mitochondrial biliverdin exporter ABCB10, which increases hepatocyte-autonomous synthesis of the ROS-scavenger bilirubin, is decreased in livers from humans and mice with AH. Increasing ABCB10 expression selectively in hepatocytes of mice with AH is sufficient to decrease MPO gene expression and histone H3 citrullination, a specific marker of NET formation. These anti-inflammatory effects can be explained by ABCB10 function reducing ROS-mediated actions in liver. Accordingly, ABCB10 gain-of-function selectively increased the mitochondrial GSH/GSSG ratio and decreased hepatic 4-HNE protein adducts, without elevating mitochondrial fat expenditure capacity, nor mitigating steatosis and hepatocyte death. Thus, our study supports that ABCB10 function regulating ROS-mediated actions within surviving hepatocytes mitigates the maladaptive activation of infiltrated neutrophils in AH. Consequently, ABCB10 gain-of-function in human hepatocytes could potentially decrease acute liver failure by decreasing the inflammatory flare caused by excessive neutrophil activity.

Single-cell transcriptomics of peripheral blood mononuclear cells indicates impaired immune and inflammatory responses in alcohol-associated hepatitis

Alcohol-associated hepatitis (AH) is often diagnosed at advanced stages, and severe AH usually carries poor prognosis and high short-term mortality. In addition, it is challenging to understand the molecular mechanisms of immune dysregulation and inflammation in AH due to the cellular complexity and heterogeneity. Using single-cell RNA sequencing, previous studies found that AH causes dysfunctional innate immune response in monocytes, involving activation of pattern recognition receptors (PRRs) and cytokine signaling pathways. To better understand the coordinated systemic immune response in AH patients, we performed combined single-cell transcriptome, cell-surface protein, and lymphocyte antigen receptor analysis of peripheral blood mononuclear cell (PBMC) samples. Our results showed inflammatory cytokines and chemokines were highly expressed in AH, including IL-2, IL-32, CXC3R1 and CXCL16 in monocytes and NK cells, whereas HLA-DR genes were reduced in monocytes. In addition, we also found altered differentiation of T-helper cells (TH1 and TH17), which could further lead to neutrophil recruitment and macrophage activation. Lastly, our results also suggest impaired NK-cell activation and differentiation in AH with reduced gene expression of KLRC2 and increased gene expression of KLRG1. Our findings indicate different mechanisms may be involved in impaired immune and inflammatory responses for the cellular subtypes of the PBMCs in AH.

Long non-coding RNA HOX transcript antisense intergenic RNA depletion protects against alcoholic hepatitis through the microRNA-148a-3p/sphingosine 1-phosphate receptor 1 axis

The aggravating role of long noncoding RNA (lncRNA) HOTAIR has been indicated in liver injury caused by hepatic ischemia/reperfusion. However, under the condition of alcoholic hepatitis (AH), its effects remain unclear. The present study aimed to examine the effect of lncRNA HOTAIR on hepatic stellate cell viability and apoptosis during liver injury caused by AH. In the liver tissues of AH rats, HOTAIR and S1PR1 were overexpressed, and microRNA (miR)-148a-3p was poorly expressed. Loss-of-function assays revealed that silencing of HOTAIR alleviated liver injury in AH by inhibiting the activated phenotype of hepatic stellate cells, inflammation, and fibrosis. Using the bioinformatics databases, dual-luciferase, RIP, and FISH assays, we observed that HOTAIR was mainly localized in the cytoplasm of hepatic stellate cells, and HOTAIR could bind specifically to miR-148a-3p. In addition, miR-148a-3p could target S1PR1 expression. Rescue experiments showed that silencing of miR-148a-3p or overexpression of S1PR1 reversed the alleviating effects of HOTAIR silencing on liver injury. Taken together, our findings revealed that HOTAIR regulates hepatic stellate cell proliferation via the miR-148a-3p/S1PR1 axis in liver injury, which may serve as the basis for developing novel therapeutic strategies to treat AH.

5S rRNA pseudogene transcripts are associated with interferon production and inflammatory responses in alcohol-associated hepatitis

BACKGROUND AND AIMS

Interferon (IFN) signaling is critical to the pathogenesis of alcohol-associated hepatitis (AH), yet the mechanisms for activation of this system are elusive. We hypothesize that host-derived 5S rRNA pseudogene (RNA5SP) transcripts regulate IFN production and modify immunity in AH.

APPROACH AND RESULTS

Mining of transcriptomic datasets revealed that in patients with severe alcohol-associated hepatitis (sAH), hepatic expression of genes regulated by IFNs was perturbed and gene sets involved in IFN production were enriched. RNA5SP transcripts were also increased and correlated with expression of type I IFNs. Interestingly, inflammatory mediators upregulated in sAH, but not in other liver diseases, were positively correlated with certain RNA5SP transcripts. Real-time quantitative PCR demonstrated that RNA5SP transcripts were upregulated in peripheral blood mononuclear cells (PBMCs) from patients with sAH. In sAH livers, increased 5S rRNA and reduced nuclear MAF1 (MAF1 homolog, negative regulator of RNA polymerase III) protein suggested a higher activity of RNA polymerase III (Pol III); inhibition of Pol III reduced RNA5SP expression in monocytic THP-1 cells. Expression of several RNA5SP transcript-interacting proteins was downregulated in sAH, potentially unmasking transcripts to immunosensors. Indeed, siRNA knockdown of interacting proteins potentiated the immunostimulatory activity of RNA5SP transcripts. Molecular interaction and cell viability assays demonstrated that RNA5SP transcripts adopted Z-conformation and contributed to ZBP1-mediated caspase-independent cell death.

CONCLUSIONS

Increased expression and binding availability of RNA5SP transcripts was associated with hepatic IFN production and inflammation in sAH. These data identify RNA5SP transcripts as a potential target to mitigate inflammation and hepatocellular injury in AH.

Apolipoprotein A-IV Has Bi-Functional Actions in Alcoholic Hepatitis by Regulating Hepatocyte Injury and Immune Cell Infiltration

Alcohol abuse can lead to alcoholic hepatitis (AH), a worldwide public health issue with high morbidity and mortality. Here, we identified apolipoprotein A-IV (APOA4) as a biomarker and potential therapeutic target for AH. APOA4 expression was detected by Gene Expression Omnibus (GEO) databases, Immunohistochemistry, and qRT-PCR in AH. Bioinformatics Methods (protein-protein interaction (PPI) network, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and Gene Set Enrichment Analysis (GSEA) were used to show down-stream gene and pathways of APOA4 in AH. AML-12 cells were used to evaluate the biological function of APOA4 using an ELISA kit (AST, ALT, and IL-1β) and flow cytometry (ROS activity). Both in vivo and in vitro, APOA4 expression was significantly elevated in the AH model induced by alcohol (ETOH). AML-12 cell damage was specifically repaired by APOA4 deficiency, while AST, ALT, and IL-1β activity that was increased by ETOH (200 µmol, 12 h) were suppressed. APOA4 inhibition increased intracellular ROS induced by ETOH, which was detected by flow cytometry. Functional and PPI network analyses showed Fcgamma receptor (FCGR) and platelet activation signaling were potential downstream pathways. We identified CIDEC as a downstream gene of APOA4. The CIDEC AUC values for the ROC curves were 0.861. At the same time, APOA4 silencing downregulated the expression of CIDEC, whereas the knockdown of CIDEC did not influence the expression of APOA4 in AML-12 cells. Collectively, APOA4 regulates CIDEC expression and immune cell infiltration and may hold great potential as a biomarker and therapeutic target for AH.

Impaired regulation of PMCA activity by defective CFTR expression promotes epithelial cell damage in alcoholic pancreatitis and hepatitis

Alcoholic pancreatitis and hepatitis are frequent, potentially lethal diseases with limited treatment options. Our previous study reported that the expression of CFTR Cl- channel is impaired by ethanol in pancreatic ductal cells leading to more severe alcohol-induced pancreatitis. In addition to determining epithelial ion secretion, CFTR has multiple interactions with other proteins, which may influence intracellular Ca2+ signaling. Thus, we aimed to investigate the impact of ethanol-mediated CFTR damage on intracellular Ca2+ homeostasis in pancreatic ductal epithelial cells and cholangiocytes. Human and mouse pancreas and liver samples and organoids were used to study ion secretion, intracellular signaling, protein expression and interaction. The effect of PMCA4 inhibition was analyzed in a mouse model of alcohol-induced pancreatitis. The decreased CFTR expression impaired PMCA function and resulted in sustained intracellular Ca2+ elevation in ethanol-treated and mouse and human pancreatic organoids. Liver samples derived from alcoholic hepatitis patients and ethanol-treated mouse liver organoids showed decreased CFTR expression and function, and impaired PMCA4 activity. PMCA4 co-localizes and physically interacts with CFTR on the apical membrane of polarized epithelial cells, where CFTR-dependent calmodulin recruitment determines PMCA4 activity. The sustained intracellular Ca2+ elevation in the absence of CFTR inhibited mitochondrial function and was accompanied with increased apoptosis in pancreatic epithelial cells and PMCA4 inhibition increased the severity of alcohol-induced AP in mice. Our results suggest that improving Ca2+ extrusion in epithelial cells may be a potential novel therapeutic approach to protect the exocrine pancreatic function in alcoholic pancreatitis and prevent the development of cholestasis in alcoholic hepatitis.

Loss of hepatocyte identity following aberrant YAP activation: A key mechanism in alcoholic hepatitis

BACKGROUND & AIMS

Alcoholic hepatitis (AH) is a life-threatening disease with limited therapeutic options, as the molecular mechanisms leading to death are not well understood. This study evaluates the Hippo/Yes-associated protein (YAP) pathway which has been shown to play a role in liver regeneration.

METHOD

The Hippo/YAP pathway was dissected in explants of patients transplanted for AH or alcohol-related cirrhosis and in control livers, using RNA-seq, real-time PCR, western blot, immunohistochemistry and transcriptome analysis after laser microdissection. We transfected primary human hepatocytes with constitutively active YAP (YAPS127A) and treated HepaRG cells and primary hepatocytes isolated from AH livers with a YAP inhibitor. We also used mouse models of ethanol exposure (Lieber de Carli) and liver regeneration (carbon tetrachloride) after hepatocyte transduction of YAPS127A.

RESULTS

In AH samples, RNA-seq analysis and immunohistochemistry of total liver and microdissected hepatocytes revealed marked downregulation of the Hippo pathway, demonstrated by lower levels of active MST1 kinase and abnormal activation of YAP in hepatocytes. Overactivation of YAP in hepatocytes in vitro and in vivo led to biliary differentiation and loss of key biological functions such as regeneration capacity. Conversely, a YAP inhibitor restored the mature hepatocyte phenotype in abnormal hepatocytes taken from patients with AH. In ethanol-fed mice, YAP activation using YAPS127A resulted in a loss of hepatocyte differentiation. Hepatocyte proliferation was hampered by YAPS127A after carbon tetrachloride intoxication.

CONCLUSION

Aberrant activation of YAP plays an important role in hepatocyte transdifferentiation in AH, through a loss of hepatocyte identity and impaired regeneration. Thus, targeting YAP is a promising strategy for the treatment of patients with AH.

LAY SUMMARY

Alcoholic hepatitis is characterized by inflammation and a life-threatening alteration of liver regeneration, although the mechanisms behind this have not been identified. Herein, we show that liver samples from patients with alcoholic hepatitis are characterized by profound deregulation of the Hippo/YAP pathway with uncontrolled activation of YAP in hepatocytes. We used human cell and mouse models to show that inhibition of YAP reverts this hepatocyte defect and could be a novel therapeutic strategy for alcoholic hepatitis.

Super enhancer regulation of cytokine-induced chemokine production in alcoholic hepatitis

Alcoholic hepatitis (AH) is associated with liver neutrophil infiltration through activated cytokine pathways leading to elevated chemokine expression. Super-enhancers are expansive regulatory elements driving augmented gene expression. Here, we explore the mechanistic role of super-enhancers linking cytokine TNFα with chemokine amplification in AH. RNA-seq and histone modification ChIP-seq of human liver explants show upregulation of multiple CXCL chemokines in AH. Liver sinusoidal endothelial cells (LSEC) are identified as an important source of CXCL expression in human liver, regulated by TNFα/NF-κB signaling. A super-enhancer is identified for multiple CXCL genes by multiple approaches. dCas9-KRAB-mediated epigenome editing or pharmacologic inhibition of Bromodomain and Extraterminal (BET) proteins, transcriptional regulators vital to super-enhancer function, decreases chemokine expression in vitro and decreases neutrophil infiltration in murine models of AH. Our findings highlight the role of super-enhancer in propagating inflammatory signaling by inducing chemokine expression and the therapeutic potential of BET inhibition in AH treatment.

Integrated Multiomics Reveals Glucose Use Reprogramming and Identifies a Novel Hexokinase in Alcoholic Hepatitis

BACKGROUND & AIMS

We recently showed that alcoholic hepatitis (AH) is characterized by dedifferentiation of hepatocytes and loss of mature functions. Glucose metabolism is tightly regulated in healthy hepatocytes. We hypothesize that AH may lead to metabolic reprogramming of the liver, including dysregulation of glucose metabolism.

METHODS

We performed integrated metabolomic and transcriptomic analyses of liver tissue from patients with AH or alcoholic cirrhosis or normal liver tissue from hepatic resection. Focused analyses of chromatin immunoprecipitation coupled to DNA sequencing was performed. Functional in vitro studies were performed in primary rat and human hepatocytes and HepG2 cells.

RESULTS

Patients with AH exhibited specific changes in the levels of intermediates of glycolysis/gluconeogenesis, the tricarboxylic acid cycle, and monosaccharide and disaccharide metabolism. Integrated analysis of the transcriptome and metabolome showed the used of alternate energetic pathways, metabolite sinks and bottlenecks, and dysregulated glucose storage in patients with AH. Among genes involved in glucose metabolism, hexokinase domain containing 1 (HKDC1) was identified as the most up-regulated kinase in patients with AH. Histone active promoter and enhancer markers were increased in the HKDC1 genomic region. High HKDC1 levels were associated with the development of acute kidney injury and decreased survival. Increased HKDC1 activity contributed to the accumulation of glucose-6-P and glycogen in primary rat hepatocytes.

CONCLUSIONS

Altered metabolite levels and messenger RNA expression of metabolic enzymes suggest the existence of extensive reprogramming of glucose metabolism in AH. Increased HKDC1 expression may contribute to dysregulated glucose metabolism and represents a novel biomarker and therapeutic target for AH.

Hepatic lipocalin 2 promotes liver fibrosis and portal hypertension

Advanced fibrosis and portal hypertension influence short-term mortality. Lipocalin 2 (LCN2) regulates infection response and increases in liver injury. We explored the role of intrahepatic LCN2 in human alcoholic hepatitis (AH) with advanced fibrosis and portal hypertension and in experimental mouse fibrosis. We found hepatic LCN2 expression and serum LCN2 level markedly increased and correlated with disease severity and portal hypertension in patients with AH. In control human livers, LCN2 expressed exclusively in mononuclear cells, while its expression was markedly induced in AH livers, not only in mononuclear cells but also notably in hepatocytes. Lcn2-/- mice were protected from liver fibrosis caused by either ethanol or CCl4 exposure. Microarray analysis revealed downregulation of matrisome, cell cycle and immune related gene sets in Lcn2-/- mice exposed to CCl4, along with decrease in Timp1 and Edn1 expression. Hepatic expression of COL1A1, TIMP1 and key EDN1 system components were elevated in AH patients and correlated with hepatic LCN2 expression. In vitro, recombinant LCN2 induced COL1A1 expression. Overexpression of LCN2 increased HIF1A that in turn mediated EDN1 upregulation. LCN2 contributes to liver fibrosis and portal hypertension in AH and could represent a new therapeutic target.

NLRP6 exerts a protective role via NF-kB with involvement of CCL20 in a mouse model of alcoholic hepatitis

Alcoholic hepatitis (AH) is an important form of alcoholic liver disease (ALD), and its incidence is continuously increasing leading to advanced disease burden. The NOD-like receptors (NLRs) are a specialized group of intracellular pattern recognition receptors, which participate in inflammatory diseases. However, the role of NLRs in the pathogenesis of AH still remain obscure. The animal model of alcoholic hepatitis in mice was established according to National Institute on Alcohol Abuse and Alcoholism (NIAAA) method. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to analyze the expression of NLR family members in liver tissues of the ethanol-fed(EtOH-fed)group and pair-fed group. NLRP6 was overexpressed in mice by injecting Recombinant Adeno-Associated Virus into the tail vein. Mouse Cytokines and Chemokines RT² Profiler PCR Array was used to analyze the related cytokines and chemokines involved in the development of alcoholic hepatitis. Among the NLR family members, the expression of NLRP6 decreased most significantly in the animal model of AH. Our results demonstrated that overexpression of NLRP6 in vivo obviously alleviated steatosis, inflammation and fibrosis in liver. Meanwhile, the serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in mice also decreased. Besides, Chemokine (C-C motif) ligand 20(CCL20) was one of the most significantly up-regulated chemokines in the mouse AH model and CCL20 was participated in NLRP6-mediated AH. NLRP6 could inhibit the activation of nuclear factor (NF)-κB signaling pathway in vitro and in vivo. Furthermore, the activation, proliferation, and migration of hepatic stellate cells was enhanced after downregulation of NLRP6. In summary, NLRP6 may play a protective role in the development of AH. NLRP6 could inhibit activation of NF-κB signaling pathway in AH.

Epithelial splicing regulatory protein 2-mediated alternative splicing reprograms hepatocytes in severe alcoholic hepatitis

Severe alcoholic hepatitis (SAH) is a deadly liver disease without an effective medical therapy. Although SAH mortality is known to correlate with hepatic accumulation of immature liver cells, why this occurs and how it causes death are unclear. Here, we demonstrate that expression of epithelial splicing regulatory protein 2 (ESRP2), an RNA-splicing factor that maintains the nonproliferative, mature phenotype of adult hepatocytes, was suppressed in both human SAH and various mouse models of SAH in parallel with the severity of alcohol consumption and liver damage. Inflammatory cytokines released by excessive alcohol ingestion reprogrammed adult hepatocytes into proliferative, fetal-like cells by suppressing ESRP2. Sustained loss of ESRP2 permitted reemergence of a fetal RNA-splicing program that attenuates the Hippo signaling pathway and thus allows fetal transcriptional regulators to accumulate in adult liver. We further showed that depleting ESRP2 in mice exacerbated alcohol-induced steatohepatitis, enabling surviving hepatocytes to shed adult hepatocyte functions and become more regenerative, but threatening overall survival by populating the liver with functionally immature hepatocytes. Our findings revealed a mechanism that explains why liver failure develops in patients with the clinical syndrome of SAH, suggesting that recovery from SAH might be improved by limiting adult-to-fetal reprogramming in hepatocytes.

Perturbations in Mitochondrial Dynamics Are Closely Involved in the Progression of Alcoholic Liver Disease

BACKGROUND

Mitochondria play a fundamental role in the pathogenesis of alcoholic liver disease (ALD). The preservation of functional mitochondria during toxic alcohol insults is essential for cell survival and is maintained by key processes known as mitochondrial dynamics, including fragmentation and fusion, which are regulated by mitochondria-shaping proteins (MSP). We have shown mitochondrial dynamics to be distorted by alcohol in cellular and animal models, but the effect in humans remains unknown.

METHODS

Hepatic gene expression of the main MSP involved in the mitochondrial fusion and fragmentation pathways was evaluated in patients with alcoholic hepatitis (AH) by DNA microarray (n = 15) and Reverse Transcription Polymerase Chain Reaction (n = 32). The activation of dynamin-1-like protein (Drp1) was also investigated in mitochondria isolated from liver biopsies of ALD patients (n = 8). The effects of alcohol on mitochondrial dynamics and on MSP protein expression were studied in human precision-cut liver slices (PCLS) exposed for 24 hours to increasing doses of ethanol (EtOH; 50 to 250 mM).

RESULTS

A profound hyperactivation of the fragmentation pathway was observed in AH patients, with a significant increase in the expression of Drp1 and its adapters/receptors. The translocation of Drp1 to the mitochondria was also induced in patients with severe ALD and was affected in the PCLS with short-term exposure to EtOH but only mildly. The fusion pathway was not altered in ALD, and this was confirmed in the PCLS model.

CONCLUSIONS

The present study reveals the role of mitochondrial dynamics in human ALD, confirming our previous observations in animal and cell culture models of ALD. Taken together, we show that alcohol has a significant impact on the fragmentation pathway, and we confirm Drp1 as a potential therapeutic target in severe ALD.

Dysregulated Autophagy and Lysosome Function Are Linked to Exosome Production by Micro-RNA 155 in Alcoholic Liver Disease

Cellular homeostais, that is normally maintained through autophagy, is disrupted in alcoholic liver disease (ALD). Because autophagy and exosome biogenesis share common elements, we hypothesized that increased exosome production in ALD may be linked to disruption of autophagic function. We found impaired autophagy both in ALD and alcoholic hepatitis (AH) mouse models and human livers with ALD as indicated by increased hepatic p62 and LC3-II levels. Alcohol reduced autophagy flux in vivo in chloroquine-treated mice as well as in vitro in hepatocytes and macrophages treated with bafilomycin A. Our results revealed that alcohol targets multiple steps in the autophagy pathway. Alcohol-related decrease in mechanistic target of rapamycin (mTOR) and Ras homolog enriched in brain (Rheb), that initiate autophagy, correlated with increased Beclin1 and autophagy-related protein 7 (Atg7), proteins involved in phagophore-autophagosome formation, in ALD. We found that alcohol disrupted autophagy function at the lysosomal level through decreased lysosomal-associated membrane protein 1 (LAMP1) and lysosomal-associated membrane protein 2 (LAMP2) in livers with ALD. We identified that micro-RNA 155 (miR-155), that is increased by alcohol, targets mTOR, Rheb, LAMP1, and LAMP2 in the authophagy pathway. Consistent with this, miR-155-deficient mice were protected from alcohol-induced disruption of autophagy and showed attenuated exosome production. Mechanistically, down-regulation of LAMP1 or LAMP2 increased exosome release in hepatocytes and macrophages in the presence and absence of alcohol. These results suggested that the alcohol-induced increase in exosome production was linked to disruption of autophagy and impaired autophagosome and lysosome function. Conclusion: Alcohol affects multiple genes in the autophagy pathway and impairs autophagic flux at the lysosome level in ALD. Inhibition of LAMP1 and LAMP2 promotes exosome release in ALD. We identified miR-155 as a mediator of alcohol-related regulation of autophagy and exosome production in hepatocytes and macrophages.

Alcohol-related changes in the intestinal microbiome influence neutrophil infiltration, inflammation and steatosis in early alcoholic hepatitis in mice

Background

Alcohol-induced intestinal dysbiosis disrupts homeostatic gut-liver axis function and is essential in the development of alcoholic liver disease. Here, we investigate changes in enteric microbiome composition in a model of early alcoholic steatohepatitis and dissect the pathogenic role of intestinal microbes in alcohol-induced liver pathology.

Materials and methods

Wild type mice received a 10-day diet that was either 5% alcohol-containing or an isocaloric control diet plus a single binge. 16S rDNA sequencing defined the bacterial communities in the cecum of alcohol- and pair-fed animals. Some mice were treated with an antibiotic cocktail prior to and throughout alcohol feeding. Liver neutrophils, cytokines and steatosis were evaluated.

Results

Acute-on-chronic alcohol administration induced shifts in various bacterial phyla in the cecum, including increased Actinobacteria and a reduction in Verrucomicrobia driven entirely by a reduction in the genus Akkermansia. Antibiotic treatment reduced the gut bacterial load and circulating bacterial wall component lipopolysaccharide (LPS). We found that bacterial load suppression prevented alcohol-related increases in the number of myeloperoxidase- (MPO) positive infiltrating neutrophils in the liver. Expression of liver mRNA tumor necrosis factor alpha (Tnfα), C-X-C motif chemokine ligand 1 (Cxcl1) and circulating protein monocyte chemoattractant protein-1 (MCP-1) were also reduced in antibiotic-treated alcohol-fed mice. Alcohol-induced hepatic steatosis measured by Oil-Red O staining was significantly reduced in antibiotic treated mice. Genes regulating lipid production and storage were also altered by alcohol and antibiotic treatment. Interestingly, antibiotic treatment did not protect from alcohol-induced increases in serum aminotransferases (ALT/AST).

Conclusions

Our data indicate that acute-on-chronic alcohol feeding alters the microflora at multiple taxonomic levels and identifies loss of Akkermansia as an early marker of alcohol-induced gut dysbiosis. We conclude that gut microbes influence liver inflammation, neutrophil infiltration and liver steatosis following alcohol consumption and these data further emphasize the role of the gut-liver axis in early alcoholic liver disease.

Over expression of proteins that alter the intracellular signaling pathways in the cytoplasm of the liver cells forming Mallory-Denk bodies

In this study, liver biopsy sections fixed in formalin and embedded in paraffin (FFPE) from patients with alcoholic hepatitis (AH) were used. The results showed that the expression of the SYK protein was up regulated by RNA-seq and real time PCR analyses in the alcoholic hepatitis patients compared to controls. The results were supported by using the IHC fluorescent antibody staining intensity morphometric quantitation. Morphometric quantification of fluorescent intensity measurement showed a two fold increase in SYK protein in the cytoplasm of the cells forming MDBs compared to surrounding normal hepatocytes. The expression of AKT1 was also analyzed. AKT1 is a serine/threonine-specific protein kinase that plays a key role in multiple cellular processes such as glucose metabolism, apoptosis, cell proliferation, transcription and cell migration. The AKT protein was also increased in hepatocyte balloon cells forming MDBs. This observation demonstrates the role of SYK and its subsequent effect on the internal signaling pathways such as PI3K/AKT as well as p70S6K, as a potential multifunctional target in protein quality control mechanisms of hepatocytes when ER stress is activated.

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.

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.

Predicting transcription factors in human alcoholic hepatitis from gene regulatory network

OBJECTIVE

Alcoholic hepatitis (AH) is a type of alcoholic liver disorder caused by overconsumption of alcohol. The involvement of several transcription factors (TF), as the main regulators of disease related gene expression has been documented previously. However, despite the importance of analysis of gene regulatory network for understanding the molecular basis in any disease, so far, there is no report on construction of such network for AH in human.

MATERIALS AND METHODS

Here, we used microarray analysis to construct a rather complete gene regulatory network and used it to predict TFs and pathways that affected by this disease.

RESULTS

Ten TFs were shown to undergo significant alteration in AH. These TFs are AR, EGR1, MYC, TCF4, ATF3, JUN, FOXO3, STAT1, HIF1A and EOMES, where ATF3, TCF4 and MYC are the new TFs with a role in AH. Comparisons of gene expression profile of patients with those of healthy persons indicates 820 differentially expressed (DE) genes. Network analysis indicates that, these ten TFs regulate expression of 516 DE genes (out of 820 genes), by 1057 interactions. Furthermore, we report pathways that significantly affected by these ten TFs.

CONCLUSIONS

These results may contribute to our limited understanding of the molecular basis of AH.

Protein S exacerbates alcoholic hepatitis by stimulating liver natural killer T cells

BACKGROUND

Alcohol consumption is a major cause of liver injury but the mechanisms are not completely understood. Protein S (PS) is an anticoagulant glycoprotein with multiple functions. The role of PS in liver injury is unknown.

OBJECTIVES

This study investigated the role of PS in acute alcoholic hepatitis.

METHODS

A mouse overexpressing human PS (hPS-TG) was generated in which acute hepatitis was induced by intraperitoneal injection of ethanol.

RESULTS

The levels of serum liver enzymes and liver tissue inflammatory cytokines and the degree of hepatic steatosis were significantly increased in hPS-TG mice treated with ethanol compared with ethanol-treated wild type (WT) mice. Cell expansion, activation and inhibition of apoptosis were significantly augmented in natural killer T (NKT) cells from hPS-TG mice compared with WT mice. Liver mononuclear cells from hPS-TG mice express higher levels of inflammatory cytokines than those from WT mice after stimulation with a specific stimulant of NKT cells in vitro. In a co-culture system of hepatocytes and NKT cells, the effects of PS on ethanol-mediated cell injury were suppressed by a CD1d neutralizing antibody. Alcoholic liver injury was significantly improved in mice pre-treated with PS siRNA and anti-protein S antibody compared with control mice. Patients with alcoholic hepatitis showed significantly increased plasma PS levels and enhanced liver expression of PS and CD1d compared with controls.

CONCLUSIONS

The results of this study suggest that PS exacerbates acute alcoholic hepatitis by inhibiting apoptosis of activated NKT cells.

Mutation of mitochondrial DNA in livers from patients with alcoholic hepatitis and nonalcoholic steatohepatitis

BACKGROUND

In alcoholic hepatitis (Al-Hep) and nonalcoholic steatohepatitis (NASH), triglycerides accumulate in hepatocytes. We examined the hypothesis that mutations in mitochondrial DNA may take place by mitochondrial overwork, resulting in dysfunction of mitochondria.

SUBJECTS AND METHODS

Subjects of this research were 8 cases each of Al-Hep, NASH, and fatty liver (FL). Total DNA was extracted from the biopsied liver samples. DNA fragments were amplified by PCR and DNA sequences determined in the control and coding regions of mitochondrion.

RESULTS

When the numbers of mutations per 1,000 bases of mitochondrial DNA were compared between each group, no significant differences were found among D-loop, HV1, and HV2 mitochondrial DNA regions. However, there were significantly more mutations in ND1 and COII of Al-Hep and NASH than in FL, and mutations were comparatively at random. Neither a region in which mutations were focused nor differences among the groups were recognized. When details of the base mutation in a control region were investigated by group, the transition type of mutation between T:A<<->>C:G occurred in at least 70%. Also, a transition-type mutation was found mostly in a coding region, which was similar to the mutation pattern in the control region, except for the ND1 and COII regions where there were hardly any mutations.

CONCLUSIONS

As gene mutations of mitochondrial DNA appeared frequently in Al-Hep, and also in NASH, mitochondrial dysfunction caused by mutation in mitochondrial DNA may be involved in the pathogenesis of both diseases.

Increased gene and protein expression of the novel eNOS regulatory protein NOSTRIN and a variant in alcoholic hepatitis

BACKGROUND & AIMS

Increased intrahepatic resistance in cirrhosis is associated with reduced endothelial NO synthase (eNOS) activity and exacerbated by superimposed inflammation. NOSTRIN induces intracellular translocation of eNOS and reduces NO generation. Our aims were to quantify and compare hepatic expression of eNOS, NOSTRIN, NOSIP, and caveolin-1 in alcoholic cirrhosis with or without superimposed alcoholic hepatitis and in normal livers.

METHODS

Biopsy specimens from 20 decompensated alcoholic cirrhotic patients with portal hypertension (10 with alcoholic hepatitis) and 6 normal livers were analyzed: real-time polymerase chain reaction for quantification of messenger RNA; Western blotting; and enzyme assays of eNOS in normal and diseased liver were performed. Localization and interaction of eNOS and NOSTRIN in liver was assessed by immunohistochemistry and co-immunoprecipitation.

RESULTS

eNOS mRNA was significantly increased and eNOS activity decreased in alcoholic hepatitis patients, despite no differences in eNOS protein expression among the patients. Patients with alcoholic hepatitis had significantly higher hepatic levels of NOSTRIN and caveolin-1 mRNA compared with cirrhosis alone or normal biopsy specimens. A NOSTRIN splice variant, not present in normal tissue, was detected on mRNA and protein levels in all alcoholic patients. Coimmunoprecipitation demonstrated association among NOSTRIN, eNOS, and caveolin-1.

CONCLUSIONS

An increase in mRNA and protein of NOSTRIN and its shortened variant in alcoholic hepatitis may partly account for the paradox of increased mRNA levels and normal protein expression but decreased enzymatic activity of eNOS in diseased liver. Such intracellular regulators of NO production may be important in the development of increased intrahepatic resistance in alcoholic hepatitis patients.

Hepatic expression of candidate genes in patients with alcoholic hepatitis: correlation with disease severity

BACKGROUND & AIMS

Alcoholic hepatitis (AH) is a form of acute-on-chronic liver failure for which current therapy is not fully effective. We investigated the hepatic expression of candidate genes in patients with AH to identify new targets for therapy.

METHODS

Hepatic expression of candidate genes (n = 46) was assessed by quantitative polymerase chain reaction in patients with AH (n = 23) and in normal livers (n = 6). Disease severity was assessed by the Maddrey's discriminant function and the occurrence of clinical complications. Histologic analysis included the assessment of myofibroblasts (smooth muscle alpha-actin), collagen deposition (Sirius red), and inflammatory infiltrate (CD43). Portal hypertension was assessed by hepatic venous pressure gradient. Predictive association between gene expression and disease severity was assessed by k-nearest neighbor analysis.

RESULTS

Patients with AH showed profound hepatocellular dysfunction advanced fibrosis, and severe portal hypertension. Livers with AH showed up-regulation of genes encoding extracellular matrix proteins (procollagen I), fibrogenesis mediators, inflammatory cytokines, and apoptosis regulators. Key components of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase were markedly up-regulated, whereas cytochrome p450 2E1 and angiotensinogen were down-regulated. The expression of tissue inhibitor of metalloproteinases-1, growth-related oncogene alpha, and several components of NADPH oxidase (dual oxidases 1 and 2) correlated with histologic findings and parameters indicative of disease severity.

CONCLUSIONS

Genes involved in hepatic fibrogenesis, inflammatory response, and oxidative stress are overexpressed in AH. Some candidate genes correlate with histologic findings and disease severity, suggesting that they may be potential targets for therapy.

Intrahepatic gene expression in human alcoholic hepatitis

BACKGROUND/AIMS

Alcoholic hepatitis remains an important cause of morbidity and mortality. Treatment remains unsatisfactory, in part, due to limited understanding of the pathogenesis. The aim of this study is to define the global intrahepatic expression profile of human alcoholic hepatitis.

METHODS

Gene expression was analysed by DNA microarray on RNA isolated from liver of patients with alcoholic hepatitis (AH, n = 8), alcoholic steatosis (AS, n = 9) and explants from non-diseased donor liver controls (ND, n = 7). Differential expression of selected genes was confirmed by real-time RT-PCR and immunohistochemistry.

RESULTS

Cluster analysis allowed differentiation of alcoholic hepatitis from alcoholic steatosis. The gene expression profile of AH revealed 586 genes differentially expressed from AS and 211 genes differentially expressed from that of ND liver. In comparison, only 98 genes were differentially expressed in AS from ND. Novel differentially expressed genes in AH in comparison to ND and AS included claudins, osteopontin, CD209, selenoprotein and genes related to bile duct proliferation. Real-time RT-PCR confirmed up-regulation of IL-8, osteopontin, and TNFRSF14 and down-regulation of SAMeS and CD209.

CONCLUSIONS

This study has defined the intrahepatic gene expression profile of human alcoholic hepatitis and revealed a number of novel differentially expressed genes.

Combined polymorphisms of tumour necrosis factor alpha and interleukin-10 genes in patients with alcoholic hepatitis

OBJECTIVES

The development and progression of alcoholic hepatitis are controlled by an extensive cytokine network which involves pro-inflammatory and anti-inflammatory cytokines. Genetic variations determining production of these cytokines have been described and the susceptibility to the disease may be determined by an imbalance in the expression of several candidate genes.

METHODS

We have studied biallelic single nucleotide polymorphisms at positions (-308) and (-238) in the promoter region of the pro-inflammatory tumour necrosis factor alpha (TNF-alpha) and at positions (-1,082) and (-592) in the promoter of anti-inflammatory interleukin-10 (IL-10) in 134 patients with severe biopsy-proven alcoholic hepatitis and 145 healthy subjects.

RESULTS

The frequency distribution of isolated cytokine genotypes did not differ between the two groups. The combination of at least one A or A allele for TNF-alpha, associated with a TNF-alpha high-producer phenotype, and one A or A allele for IL-10, associated with an IL-10 low-producer phenotype, was less frequent in patients (20.9 vs 33.8%, P=0.016, OR (95% CI)=0.52 (0.30-0.89)). The same combination in patients was associated with a higher risk of septic complications (32.5 vs 16.0%, P=0.031, OR (95% CI)=1.79 (1.07-6.00)) but not with in-hospital mortality.

CONCLUSIONS

We have not found any relationship between the isolated polymorphisms and the risk of alcoholic hepatitis. Moreover, the imbalance between the pro-inflammatory and anti-inflammatory responses leading to high TNF-alpha production and low IL-10 was uncommon in alcoholic hepatitis. However, patients with this particular genotype appeared more susceptible to severe septic complications.

[Genetic susceptibility to the development of acute alcoholic hepatitis: role of genetic mutations in dehydrogenase alcohol, aldehyde dehydrogenase and cytochrome P450 2E1]

OBJECTIVE

Analyze the frequencies of genetic mutation in alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH) and cytochrome P450 2E1 (CYP2E1) and establish their possible association with the development of acute alcoholic hepatitis (AAH).

METHODOLOGY

Case-control study in a total of 85 Spanish patients. We distinguish three groups (one case group and two control groups) based on hepatic histological lesion and alcohol consumption: controls (group 1: teetotalers; group 2: drinkers without AAH; cases: group 3: drinkers with AAH). Case diagnosis was established based on the presence of polymorphonuclear leukocyte infiltrate in histological study. We analyzed the presence of the genetic mutations R47H and R369C (ADH2), E487K (ALDH2) and mutation Rsa I of CYP2E1 (allele c2) by polymerase chain reaction (PCR) and capillary electrophoresis.

RESULTS

The allele c2 of CYP2E1 was found in 10%, 16% and 50% of the groups 1, 2 and 3 patients, respectively. Presence of the mutation Rsa I showed influence on the development of AAH (odds ratio [OR]: 3.63; confidence interval (95% [CI]: 0.88-15.02).

CONCLUSIONS

The data suggest a possible association between the presence of the Rsa I of CYP2E1 and the development of AAH in patients with chronic alcohol consumption.

Identification of the antigens predominantly reacted with serum from patients with hepatocellular carcinoma

BACKGROUND

To identify antigens specifically recognized by the immune surveillance system in patients with hepatocellular carcinoma (HCC), the authors examined two complementary DNA (cDNA) libraries of moderately differentiated HCC by serologic analysis of recombinant cDNA expression libraries (SEREX).

METHODS

The libraries were screened with autologous patients' sera, and sequences of the reacted clones were determined. To study the immunoreactivity of the antigens, sera from 20 patients with HCC, from 20 healthy volunteers, and from 16 patients with chronic viral hepatitis were examined.

RESULTS

Twenty-seven antigens were identified. They included SART1, p57Kip2, ROCK-1, gamma-catenin, and heat shock proteins, which are classified as tumor-associated genes. Three of 27 antigens-Tat-binding protein-1 (TBP-1), beta4 integrin-binding protein (p27[BBP]), and ribosomal protein L30 (rpL30)-were reacted predominantly with sera from patients with HCC (55% of patients, 45% of patients, and 20% of patients, respectively). Patients in the control group had no antibodies against these three antigens. Seventy percent of patients with HCC had the antibody against at least one of these antigens.

CONCLUSIONS

Disease specific humoral immune response against TBP-1, p27(BBP), and rpL30 was induced in patients with HCC, and the antibodies against these antigens also may be used as tumor markers.

LPO and ethanol biotransformation systems in the liver as markers of predisposition to ethanol hepatotoxicity

An original experimental model for detecting organ-specific markers of predisposition to ethanol hepatotoxicity is proposed. A relationship between congenital activity of LPO processes in rat liver (before ethanol intoxication) and the type and severity of ethanol-induced damage to the liver was demonstrated using methods of mathematical modeling. It was proven that intact rats with genetically high MDA levels in the liver and more active systems of MDA generation in ascorbate- and NADPH-dependent reactions are prone to ethanol-induced damage to the liver.

Valine-alanine manganese superoxide dismutase polymorphism is not associated with alcohol-induced oxidative stress or liver fibrosis

The role of genetic factors in the pathogenesis of alcohol-induced liver disease (ALD) is receiving increasing attention. Recently, it has been reported that homozygosity for a valine to alanine substitution in the mitochondrial targeting sequence of manganese superoxide dismutase (Mn-SOD) represents a risk factor for severe ALD. Because this mutation is postulated to modify enzyme transport into mitochondria, we have sought confirmatory evidence of this association in a larger group of patients and investigated whether this polymorphism might influence alcohol-induced oxidative stress. Genotyping for the valine-alanine (Val-Ala) polymorphism of the Mn-SOD gene in 281 patients with advanced ALD (cirrhosis/fibrosis) and 218 drinkers without liver disease showed no differences in either the heterozygote (55% vs. 50%) or the homozygote (19% vs. 23%) frequency for the alanine allele. By measuring the titers of circulating antibodies against oxidized cardiolipin (OX-CL) and malondialdehyde (MDA) or hydroxy-ethyl radical (HER) adducts as markers of oxidative stress, we found a significant increase in ALD patients compared with healthy controls. However, the carriers of the alanine Mn-SOD allele had titers of anti-MDA, anti-HER, and anti-OX-CL IgG comparable with heterozygotes and patients homozygous for the valine allele. Similarly, the frequency of subjects with antibody titers above the 95th percentile of controls was not increased among homozygotes for the alanine Mn-SOD allele. In conclusion, in our population Val-Ala polymorphism in Mn-SOD influences neither susceptibility to alcohol-induced liver fibrosis nor alcohol-induced oxidative stress.

Molecular pathogenesis of T lymphocyte-induced liver injury in alcoholic hepatitis

The development of alcohol-induced liver injury is, in part, a consequence of the immunological/inflammatory response that alcohol stimulates. The abnormalities of immune function in heavy drinkers have been documented well. Cytokines, especially TNF alpha, produced from macrophages/Kupffer cells, play a role in the induction of liver cell necrosis and apoptosis. TNF alpha can cause liver cell apoptosis through the TNF alpha receptor or Fas/CD95 which is expressed by liver cells. Furthermore, chronic ethanol consumption may damage the liver by inhibiting the hepatotrophic and hepatoprotective actions of TNF alpha and other cytokines. There exists an intrinsic lymphocyte population in the normal liver. Intrahepatic T lymphocytes consist of a heterogeneous population of cells that has many and varied functional characteristics in addition to classical T cell activity. The population of intrahepatic T lymphocytes may arise via a thymus-independent pathway. Our recent work has demonstrated the role of liver-associated T lymphocytes in the pathogenesis of alcohol related liver injury initiated by a variety of stimuli such as endotoxin (lipopolysaccharide, LPS) or concanavalin A (Con A). Our studies have, for the first time, suggested that alcohol consumption alone does not lead to the development of marked liver necrosis (at least in the rat), but rather that a second insult is required for this to occur. Liver-associated T lymphocytes in rats spontaneously secrete interleukin-1 alpha, interleukin-6 and TNF alpha in vitro culture. There is a significant decline in the amounts of interleukin-1 alpha and TNF alpha secreted in ethanol-consuming rats compared with non-ethanol consuming rats. The numbers of T cells, NK cells and Kupffer cells in liver perfusates remains stable over a prolonged period of ethanol consumption. However, following Con A injection, there was an inappropriate increase in the amounts of interleukin-6 and TNF alpha secreted in in vitro culture of liver-associated T lymphocytes and a significant increase in the percentage of CD4+ T cells and CD25+ T cells in liver perfusates compared with non-ethanol consuming rats. It suggested that liver-associated T lymphocytes are involved in the inflammatory process associated with alcohol related liver injury through increased cytokine secretion (TNF alpha).

[Genetic aspects of liver diseases]

Genetic factors play a privotal role in the pathogenesis of several liver diseases. A review is devoted to discussing the genetics of autoimmune hepatitis, chronic viral hepatitis B and C, cholestatic and alcoholic liver diseases, UDP-glucuronyl transferase deficiency, alpha, antitripsin deficiency, hereditary haemochromatosis, Wilson's disease and hepatocellular carcinoma.

Macrophage migration inhibitory factor expression in male and female ethanol-fed rats

Macrophage migration inhibitory factory (MIF) regulates macrophage accumulation at sites of injury and can promote the inflammatory response. We studied MIF expression in the intragastric feeding rat model for alcoholic liver injury. Male and age-matched female rats were fed ethanol or dextrose with fish oil. Two groups of male rats were fed medium-chain triglycerides with ethanol or dextrose. Analysis of liver histopathology, lipid peroxidation, endotoxin, mRNA, and immunohistochemistry for MIF, tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) were carried out. Male and female rats fed fish oil and ethanol showed necroinflammatory liver injury and had the highest expression of MIF, TNF-alpha, and IFN-gamma in the liver. Decreased levels of MIF protein were seen in rats with higher endotoxin levels, suggesting that preformed MIF is released into the circulation. MIF is an important mediator of the inflammatory response in alcoholic liver disease and a potential therapeutic target.

Reduced early alcohol-induced liver injury in CD14-deficient mice

Activation of Kupffer cells by gut-derived endotoxin is associated with alcohol-induced liver injury. Recently, it was shown that CD14-deficient mice are more resistant to endotoxin-induced shock than wild-type controls. Therefore, this study was designed to investigate the role of CD14 receptors in early alcohol-induced liver injury using CD14 knockout and wild-type BALB/c mice in a model of enteral ethanol delivery. Animals were given a high-fat liquid diet continuously with ethanol or isocaloric maltose-dextrin as control for 4 wk. The liver to body weight ratio in wild-type mice (5.8 +/- 0.3%) was increased significantly by ethanol (7.3 +/- 0.2%) but was not altered by ethanol in CD14-deficient mice. Ethanol elevated serum alanine aminotransferase levels nearly 3-fold in wild-type mice, but not in CD14-deficient mice. Wild-type and knockout mice given the control high-fat diet had normal liver histology, whereas ethanol caused severe liver injury (steatosis, inflammation, and necrosis; pathology score = 3.8 +/- 0.4). In contrast, CD14-deficient mice given ethanol showed minimal hepatic changes (score = 1.6 +/- 0.3, p < 0.05). Additionally, NF-kappa B, TGF-beta, and TNF-alpha were increased significantly in wild-type mice fed ethanol but not in the CD14 knockout. Thus, chronic ethanol feeding caused more severe liver injury in wild-type than CD14 knockouts, supporting the hypothesis that endotoxin acting via CD14 plays a major role in the development of early alcohol-induced liver injury.

[Genetic background of alcoholic liver disease]

The genetic background of alcoholic behaviour and alcoholic liver diseases has long been the target of intense research. The current knowledge of this very interesting topic is herewith summarized with special emphasis on findings and facts which might have clinical significance including results of family studies, gene polymorphisms of enzyme families of alcohol metabolism, cytokines as well as HLA antigens.

Alcoholic hepatitis as a T-cell mediated disorder: an hypothesis

BACKGROUND

The mechanism by which alcohol induces alcoholic hepatitis, the precursor lesion for cirrhosis, has never been elucidated. In particular, direct toxicity has not been proven. This article reviews the hypothesis that a primary target of chronic alcohol ingestion is the T lymphocyte. The lesion in the T lymphocyte is characterized by reduced baseline secretion of cytokines, including tumor necrosis factor-alpha; although characterized by an exaggerated release of cytokines when stimulated by polyclonal activators such as endotoxin. High concentrations of cytokines, especially tumor necrosis factor-alpha, within the liver induce necrosis/apoptosis of hepatocytes.

METHODS

Data supporting this hypothesis in rodent models are reviewed.

CONCLUSION

A strategic approach for testing this concept in man is defined.

Relationship between serum levels of anti-low-density lipoprotein-acetaldehyde-adduct antibody and aldehyde dehydrogenase 2 heterozygotes in patients with alcoholic liver injury

We prepared low-density lipoprotein (LDL)-acetaldehyde-adduct (hereafter abbreviated as LDL-adduct) and anti-LDL-adduct antibody by using Watanabe hyperlipidemic rabbits, and determined values of serum anti-LDL-adduct antibody levels by the ELISA method in healthy adults and patients with alcoholic liver injury. In the nondrinking group in healthy adults, values of anti-LDL-adduct antibody levels were 25 +/- 13 microg/ml, and there was no significant difference between moderate drinkers without diseases and the nondrinking group in healthy adults. Values of anti-LDL-adduct antibody in alcoholic disease groups, 17 +/- 9 microg/ml for the patients with the fatty liver group, 21 +/- 14 microg/ml for the hepatic fibrosis group, 70 +/- 21 microg/ml for the alcoholic hepatitis group, 41 +/- 50 microg/ml for the alcoholic cirrhosis group, and 19 +/- 18 microg/ml for the alcoholic pancreatitis group. Examinations of aldehyde dehydrogenase 2 (ALDH2) genetic variations by the polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) method in the healthy group and the liver injury group revealed a tendency for patients with ALDH2(1)/2(2) in the liver injury group to have relatively mild liver lesions. When comparing anti-LDL-adduct antibody levels between ALDH2 genetic variations, those for the patients with ALDH2(1)/2(2) (36 +/- 40 microg/ml) were significantly higher than those for patients with ALDH2(1)/2(2) (11 +/- 5 microg/ml). Results of the present study suggest that genetic variation may influence the progression of liver injury.

Association of a tumor necrosis factor promoter polymorphism with susceptibility to alcoholic steatohepatitis

Twin concordance studies suggest that genetic factors play a role in determining why only a minority of heavy drinkers develop hepatitis and cirrhosis. Tumor necrosis factor alpha (TNF-alpha) has emerged as the "final common pathway" in the pathogenesis of alcohol-related hepatic necro-inflammation. We have examined the frequency of the two recently described polymorphisms of the TNF-alpha promoter in 150 patients with biopsy-proven alcoholic liver disease and 145 healthy volunteers. There was a significant excess of the rare allele (TNFA-A; G(-238) --> A) at position -238 in patients with steatohepatitis compared with controls or patients without this lesion. This is consistent with previous suggestions that the TNFA-A allele, which falls within a putative Y regulation box of the TNF-alpha promoter, is associated with increased TNF-alpha expression. No differences were observed for the polymorphism at position -308.

Polymorphism in the cytochrome P450 2E1 gene and the risk of alcoholic liver disease

BACKGROUND/AIMS

To study the genetic susceptibility to alcoholic liver disease, we investigated the association between genetic polymorphism in the cytochrome P450 2E1 gene and the occurrence of alcoholic liver disease.

METHODS

Four previously described restriction fragment length polymorphisms (RFLPs) in the cytochrome P 450 2E1 gene were analyzed by restriction endonuclease (Dra I, Msp I, Pst I and Rsa I) digestion of polymerase chain reaction amplified DNA segments. Polymorphisms in these loci were compared to the occurrence of fatty liver, alcoholic hepatitis and liver fibrosis in 319 males comprising total abstainers, moderate alcohol consumers and chronic alcoholics.

RESULTS

The allelic frequencies for each RFLP in this series were: 0.89 and 0.11 (Dra I), 0.98 and 0.02 (Msp I) and 0.99 and 0.01 (Pst I and Rsa I). The distribution of the alleles did not vary significantly between the different consumption groups. The allelic frequencies among patients with fatty liver, alcoholic hepatitis or liver fibrosis were not significantly different from the allelic frequencies among patients with normal liver histology. Comparison of different genotypes among moderate alcohol consumers (n = 43) or chronic alcoholics (n = 243) with or without liver disease showed no statistically significant associations. However, the rare polymorphic (d2) allele in the Dra I RFLP was found slightly more often among moderate consumers as well as alcoholics with alcoholic liver disease.

CONCLUSIONS

These results indicate that the Msp I, Pst I and Rsa I RFLPs were very rare in the Finnish population, suggesting at most minor contribution to the inherited susceptibility to alcoholic liver disease. Polymorphism in the Dra I locus was more common in this study population, but showed no statistically significant association with alcoholic liver disease.

Chronic liver disease: do alcohol and hepatitis C virus interact

In chronic liver disease, alcoholism and hepatitis C virus (HCV) frequently coexist, and it is widely believed that they interact to result in more severe disease. However, the issue is far more complex and that view may be incorrect. Newer HCV assays cast doubt on the earlier results. Data acquired in one country are often at variance with those from other countries, suggesting that other factors may be involved in the variability of the disease. Further comparison of histologically different groups of individuals with excess alcohol intake is unlikely to shed further light on the issue unless information on the duration and quantity of alcohol consumption and the duration of HCV infection is available. The net evidence is that HCV and alcohol produce different histological appearances in the precirrhosis stage with the end result cirrhosis often being indistinguishable, regardless of aetiology. Nevertheless, even with both aetiologies, progression is slow and only a minority of people develop cirrhosis despite the combination of HCV and heavy alcoholism. As yet there is no definite evidence that cirrhosis develops more frequently or sooner if both HCV and alcohol are present . Although the majority of the evidence suggests that these insults are probably additive, there is a possibility that alcohol and HCV do interact in the pathogenesis of chronic liver disease. Further studies will be necessary, however, to clarify their relationship.

Alcoholism and the D2 receptor gene

The allelic association of the human dopamine D2 receptor gene and alcoholism was evaluated in 20 male alcoholics and 20 controls (sex, race, and geographic place of birth matched). This study further examines the issue of alcoholism severity and A1 allele frequency. No difference in A1 allele frequency was observed between these two groups. Similarly, no relationship between alcoholism severity and A1 frequency within the alcoholics was demonstrated.

Oxidation phenotyping in alcoholics with liver disease of varying severity

The propensity to develop alcoholic cirrhosis is probably, at least in part, genetically determined. A striking similarity exists histologically between perhexiline and alcohol-related hepatitis and both are potentially precirrhotic lesions. Liver damage due to perhexiline is associated with impaired drug oxidation capacity which is genetically determined and tested by use of debrisoquine. Oxidation phenotyping might be used to predict susceptibility to perhexiline liver damage; it might also predict the potential to develop alcoholic cirrhosis. Oxidation phenotyping was therefore undertaken, using debrisoquine in 100 alcoholic patients, 30 of whom had only fatty liver despite prolonged alcohol abuse, while the remaining 70 had alcoholic hepatitis and/or cirrhosis. One hundred patients with nonalcoholic chronic liver disease served as controls. The number of patients with severely impaired drug oxidation capacity (poor metabolizer phenotype) was similar in the alcoholic group (8%) and the nonalcoholic control group (7%). In particular, the incidence of the poor metabolizer phenotype was similar in alcoholics with severe liver disease (10%) and in those with only fatty change (3%). There appears to be no association between the susceptibility to develop alcoholic cirrhosis and drug oxidizing capacity.

Association of HLA-B40 and DRW9 with Japanese alcoholic liver cirrhosis

Seventy-seven chronic alcoholics with liver disease were studied to evaluate the HLA antigen association. There were no significant differences of HLA antigen phenotype frequencies (PF) between the patients and controls regarding A and C loci, (62 healthy Japanese). Prevalences of HLA-B40 complex (B40 . 48 . 13) and DRW9 tended to increase among chronic alcoholics. When chronic alcoholics were divided according to whether they had liver cirrhosis or not, the cirrhosis group (42 cases) revealed a significantly higher frequency of HLA-DRW9 (chi 2 = 10.88, p less than 0.001, corrected p less than 0.05, relative risk (R.R.) = 4.17) as compared to controls. There was also a tendency of B40 complex to increase in frequency (chi 2 = 5.51, p less than 0.05, R.R. = 2.65) in the cirrhosis group. Haplotype frequency and linkage disequilibrium parameters of HLA-B40 . 48-DRW9 were significantly higher than those of controls. Moreover, the increased frequency of DRW9 in the cirrhosis group was similar to that in autoimmune disease like ulcerative colitis or SLE. These data suggest that HLA-DRW9 and/or HLA-B40-DRW9 might be closely associated with susceptibility to developing alcoholic cirrhosis and that autoimmune mechanisms might be involved partly in its etiology.

Increased frequency of DR3 antigen in alcoholic hepatitis and cirrhosis

HLA-A, B and DR antigens were determined in 33 patients suffering from confirmed alcoholic hepatitis, with or without cirrhosis. Past alcohol consumption and plasma immunoglobulins were also determined in 21 cases. An increased frequency of the DR-3 antigen was found in patients as compared with the control group (a sample of the Geneva population (31% v. 11%, p less than 0.05)). Although past alcohol consumption tended to be less in DR-3 positive patients in comparison with the other patients, the difference was not significant. No other differentiating clinical, immunological or histological features were observed among DR-3 positive patients. Our findings that there appears to be an increased frequency of DR-3 antigens in patients with alcoholic hepatitis, together with the previous work showing an increased frequency of HLA-B8 in the same condition, is particularly interesting in the light of the known association of both these antigens with autoimmune disease. These results would suggest that liver damage in chronic alcoholism is genetically predisposed, and that autoimmune mechanisms could be involved in the pathogenesis of alcoholic liver disease.

HLA and alcoholic cirrhosis

In fifty-seven patients with alcoholic cirrhosis the frequency of HLA-DR2 was found to be 47.4%, in contrast to 26.1% in 119 normal subjects and 14.0% in 43 cases of autoimmune-type chronic active hepatitis (CAH). The frequencies of HLA-DR3 in the three respective groups also differed, being 24.6%, 31.9% and 74.4%. The greatly differing HLA-DR profiles in alcoholic cirrhosis and CAH point to immunogenetic differences in predisposition to these two liver diseases.