Direct effects of alcohol on hepatic fibrinolytic balance: implications for alcoholic liver disease

Establishment and application of murine models of alcoholic liver disease: A narrative review

In recent years, there have been significant advances in pathological research on alcoholic liver disease (ALD), with suitable animal models making a significant contribution. However, the currently established animal ALD models still have some significant drawbacks, especially the inability to induce the entire human ALD lineage, which may be related to physiological differences between animals and humans. This review comprehensively summarized the most widely used experimental models of ALD, including voluntary drinking, Lieber-DeCarli, Meadows-Cook, Tsukamoto-French, NIAAA, and the "second hit" model. "Second hit" refers to an additional factor that damages the liver. There are various "second hit" models that fall into two main categories: particular diets and drugs. These models can either simulate human drinking patterns more accurately or produce varying degrees of ALD without significantly increasing animal mortality. We introduced the established method of the original models, discussed the advantages and disadvantages of the existing models from the aspects of operability and practicality, and provided existing improvement methods, hoping to provide a reference for future researchers.

Sea buckthorn (Hippophae rhamnoides L.) fermentation liquid protects against alcoholic liver disease linked to regulation of liver metabolome and the abundance of gut microbiota

BACKGROUND

Alcoholic liver disease (ALD) refers to liver damage caused by long-term heavy drinking, which causes oxidative stress and changes in gut microbiota. In this paper, we investigated the hepatoprotective effect of sea buckthorn fermentation liquid on ALD in mice and the interaction between ALD and gut microbiota using animal experiments and gut microbiota measurements.

RESULTS

We found that the contents of total flavonoids, total triterpenes and related short-chain fatty acids (SCFAs) in sea buckthorn fermentation liquid (SFL) were significantly greater. Liver index, kidney index, spleen index, serum indexes of liver injury - alanine aminotransferase (ALT) and spartate aminotransferase (AST), inflammatory factors in liver tissues - tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), oxidation indexes - malondialdehyde (MDA) and superoxide dismutase (SOD), and lipid metabolism indexes - high-density liptein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), and triglyceride (TG), suggested that SFL significantly ameliorates liver injury caused by alcohol. By measuring gut microbiota in mice feces samples, we found that the high-dose group of SFL reversed the declining trend of the gut microbiota Firmicutes/Bacteroidetes (F/B) ratio caused by alcohol, reducing the number of gram-negative bacteroidetes. Patescibacteria was tightly connected with the indicators of ALD. At the genus level, high-dose SFL significantly downregulated Akkermansia, Turicibacter, Alistipes and Ruminiclostridium, and improved the abundance of beneficial bacteria in Lactobacillus. In addition, Alistipes and Ruminiclostridium was closely connected with the indicators of ALD.

CONCLUSION

Sea buckthorn fermentation liquid protected against alcoholic liver disease and modulated the composition of gut microbiota. © 2020 Society of Chemical Industry.

Hepatoprotective effect of crude polysaccharide isolated from Lycium barbarum L. against alcohol-induced oxidative damage involves Nrf2 signaling

In the present work, we investigated the effect of Lycium barbarum L. polysaccharides (LBPs) on L-02 cells exposed to alcohol exploring the potential molecular mechanisms. Our results suggested that LBPs significantly prevented alcohol-induced hepatotoxicity with dose-dependent effect, indicated by both cell viability and diagnostic indicators of liver damage. Moreover, alcohol induced excessive oxidative stress, as evidenced by an increase of the malondialdehyde level and reactive oxygen species production, while reducing antioxidant enzymes (T-SOD, CAT, and GPx) in liver, were inhibited by administration of LBPs. Furthermore, LBPs reversed the cell apoptosis and increased the mitochondrial membrane potential in alcohol-treated liver cell. Studies of underlying mechanisms revealed that LBPs increased expression levels of Nrf2 expression, which in turn blocked proapoptotic signaling events, restoring the balance between proapoptotic Bax and antiapoptotic Bcl-2 proteins, suppressing activities of cytochrome C (Cyto c), caspase-3, and caspase-9 in L-02 cells stimulation by ethanol. In general, the results showed that the inhibition of alcohol-caused liver damage by LBPs is due at least in part to its antioxidant and antiapoptosis activity via Nrf2 signaling pathway.

Antioxidant Activity and Protective Effects of Enzyme-Extracted Oudemansiella radiata Polysaccharides on Alcohol-Induced Liver Injury

This work was to examine the antioxidation in vitro and hepatoprotective effects of enzyme-extracted Oudemansiella radiata polysaccharides (En-OPS) on alcohol-induced liver damage in mice. The antioxidant activities were determined according to the scavenging effects of En-OPS on hydroxyl, superoxide, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, and the level of reducing power. En-OPS showed hepatoprotective activities on decreasing the serum levels of aspertate aminotransferase (AST), alamine aminotransferase (ALT), and alkaline phosphatase (ALP), as well as hepatic lipid levels of total cholesterol (TC) and triacylglycerols (TG). En-OPS treatment reversed the acute impairment induced by alcohol consumption, including reactive oxygen species (ROS) generation, malondialdehyde (MAD), and lipid peroxide (LPO) elevation; and superoxide dismutase (SOD), GSH peroxide (GSH-Px), catalase (CAT), and total antioxidant capacity (T-AOC) impairment. The En-OPS effectively ameliorated alcohol metabolism by activating alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), and reducing cytochrome P450 2E1 (CYP2E1) levels. Furthermore, the histopathological observations also displayed that En-OPS could alleviate liver damage. These results indicated that En-OPS could be suitable to be an ingredient of preventing alcoholic liver diseases (ALD). In addition, the preliminary structure characteristics of En-OPS were also analyzed by Fourier transform infrared (FT-IR) spectroscopy and a gas chromatography-flame ionization detector (GC-FID).

Chronic Ethanol Consumption and Generation of Etheno-DNA Adducts in Cancer-Prone Tissues

Chronic ethanol consumption is a risk factor for several human cancers. A variety of mechanisms may contribute to this carcinogenic effect of alcohol including oxidative stress with the generation of reactive oxygen species (ROS), formed via inflammatory pathways or as byproducts of ethanol oxidation through cytochrome P4502E1 (CYP2E1). ROS may lead to lipidperoxidation (LPO) resulting in LPO-products such as 4-hydoxynonenal (4-HNE) or malondialdehyde. These compounds can react with DNA bases forming mutagenic and carcinogenic etheno-DNA adducts. Etheno-DNA adducts are generated in the liver (HepG2) cells over-expressing CYP2E1 when incubated with ethanol;and are inhibited by chlormethiazole. In liver biopsies etheno-DNA adducts correlated significantly with CYP2E1. Such a correlation was also found in the esophageal- and colorectal mucosa of alcoholics. Etheno-DNA adducts also increased in liver biopsies from patients with non alcoholic steatohepatitis (NASH). In various animal models with fatty liver either induced by high fat diets or genetically modified such as in the obese Zucker rat, CYP2E1 is induced and paralleled by high levels of etheno DNA-adducts which may be modified by additional alcohol administration. As elevation of adduct levels in NASH children were already detected at a young age, these lesions may contribute to hepatocellular cancer development later in life. Together these data strongly implicate CYP2E1 as an important mediator for etheno-DNA adduct formation, and this detrimental DNA damage may act as a driving force for malignant disease progression.

Annexin A2 promotes liver fibrosis by mediating von Willebrand factor secretion

BACKGROUND

Liver fibrosis can lead to cirrhosis and hepatocellular carcinoma if not treated in the early stages. The molecular mechanisms of the pathogenesis of hepatic fibrosis remain unclear.

AIM

To identify the molecules involved in the pathogenesis of liver fibrosis and to investigate the potential effect and mechanism of Annexin A2 up-regulation during liver fibrosis progression.

METHODS

Twenty Sprague-Dawley rats were divided into two groups: the carbon tetrachloride (CCl₄)-induced liver fibrosis group and the normal control group. Hematoxylin and eosin staining or Masson Trichrome staining and enzyme-linked immunosorbent assay were applied to assess the degree of liver damage and fibrosis in rats with CCl₄-induced liver fibrosis. Liver tissue protein profiles were analyzed using iTRAQ and mass spectrometry. RT-PCR and western blotting analyses were employed to validate differentially expressed proteins. Small interfering RNA-based silencing was performed to study the function of Annexin A2.

RESULTS

Twelve weeks after CCl₄ injection, significant body weight changes and liver injury and liver fibrosis were observed in rats. In addition, 130 proteins were differentially expressed in the liver fibrosis group. Overexpression of Annexin A2 was confirmed by RT-PCR and Western blotting analysis. Silencing of Annexin A2 expression in HepG2 and LX-2 cells significantly reduced the secretion of von Willebrand factor (vWF).

CONCLUSION

Annexin A2 promotes liver fibrosis by mediating vWF secretion, which can be used to mitigate the progression of liver fibrosis.

Heat-Killed Lactobacillus salivarius and Lactobacillus johnsonii Reduce Liver Injury Induced by Alcohol In Vitro and In Vivo

The aim of the present study was to determine whether Lactobacillus salivarius (LS) and Lactobacillus johnsonii (LJ) prevent alcoholic liver damage in HepG2 cells and rat models of acute alcohol exposure. In this study, heat-killed LS and LJ were screened from 50 Lactobacillus strains induced by 100 mM alcohol in HepG2 cells. The severity of alcoholic liver injury was determined by measuring the levels of aspartate transaminase (AST), alanine transaminase (ALT), gamma-glutamyl transferase (γ-GT), lipid peroxidation, triglyceride (TG) and total cholesterol. Our results indicated that heat-killed LS and LJ reduced AST, ALT, γ-GT and malondialdehyde (MDA) levels and outperformed other bacterial strains in cell line studies. We further evaluated these findings by administering these strains to rats. Only LS was able to reduce serum AST levels, which it did by 26.2%. In addition LS significantly inhibited serum TG levels by 39.2%. However, both strains were unable to inhibit ALT levels. In summary, we demonstrated that heat-killed LS and LJ possess hepatoprotective properties induced by alcohol both in vitro and in vivo.

Transitional Remodeling of the Hepatic Extracellular Matrix in Alcohol-Induced Liver Injury

Alcohol consumption is a common custom worldwide, and the toxic effects of alcohol on several target organs are well understood. The liver is the primary site of alcohol metabolism and is therefore the major target of alcohol toxicity. Alcoholic liver disease is a spectrum of disease states, ranging from simple steatosis (fat accumulation), to inflammation, and eventually to fibrosis and cirrhosis if untreated. The fibrotic stage of ALD is primarily characterized by robust accumulation of extracellular matrix (ECM) proteins (collagens) which ultimately impairs the function of the organ. The role of the ECM in early stages of ALD is poorly understood, but recent research has demonstrated that a number of changes in the hepatic ECM in prefibrotic ALD not only are present, but may also contribute to disease progression. The purpose of this review is to summarize the established and proposed changes to the hepatic extracellular matrix (ECM) that may contribute to earlier stages of ALD development and to discuss potential mechanisms by which these changes may mediate the progression of the disease.

Hemostatic balance in patients with liver cirrhosis: Report of a consensus conference

Patients with cirrhosis present with hemostatic alterations secondary to reduced availability of pro-coagulant and anti-coagulant factors. The net effect of these changes is a rebalanced hemostatic system. The Italian Association of the Study of the Liver (AISF) and the Italian Society of Internal Medicine (SIMI) promoted a consensus conference on the hemostatic balance in patients with cirrhosis. The consensus process started with the review of the literature by a scientific board of experts and ended with a formal consensus meeting in Rome in December 2014. The statements were graded according to quality of evidence and strength of recommendations, and approved by an independent jury. The statements presented here highlight strengths and weaknesses of current laboratory tests to assess bleeding and thrombotic risk in cirrhotic patients, the pathophysiology of hemostatic perturbations in this condition, and outline the optimal management of bleeding and thrombosis in patients with liver cirrhosis.

Cyp4 A2, Apoa1, ANXA2 and DPYD are involved in anti-fibrotic effects of genistein in rats

AIM: To investigate the molecular mechanism of genistein in therapy of CCl₄-induced liver fibrosis in rats by utilizing isobaric tags for relative and absolute quantitation (iTRAQ) coupled with liquid chromatography and electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS).

METHODS: SD rats were randomly divided into a control group, a model group and a genistein therapy group. The rats of the model group and genistein therapy group were given intragastric administration of 50% CCl₄ for 15 wk to induce liver fibrosis. Genistein therapy was started at the 9^th week and lasted for 6 wk. Proteins differentially expressed in the tissue were identified by iTRAQ coupled with LC-ESI-MS/MS technology and analyzed with bioinformatics tools. The expression of representative differentia1 protein (Cyp4 A2 and A1) was validated by Western blot.

RESULTS: A total of 585 proteins were identified by MS, of which 63 were differentially expressed, including 32 up-regulated and 31 down-regulated ones. The differentially expressed proteins are involved in post-translational modification, transcription, recombination and signal transduction pathways. The tissue level of Cyp4 A2 decreased significantly in genistein therapy group compared with the model group, but Apoa1 showed a reverse trend.

CONCLUSION: Genistein can impact rat tissue protein expression. The antifibrotic effects of genistein may be due to regulation of protein expression.

Effect of multiple binge alcohol on diet-induced liver injury in a mouse model of obesity

Background:

Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are highly prevalent liver diseases that may coexist and contribute significantly to liver disease-related mortality. Obesity is a common underlying risk factor for both disorders. There has been little research investigating the combined effects of high fat diet (HFD) and alcohol. Current mouse models of alcohol- or fat-rich diet alone do not lead to severe liver injury. There is a need to develop animal models recapitulating human settings of drinking and diet to study the mechanisms of liver injury progression.

Methods:

C57BL6 male mice were fed either chow or HFD ad libitum for 12 weeks. A sub-set of mice from each group were also given alcohol (2 g kg⁻¹ body weight) twice a week via intra-gastric lavage. Animals were monitored progressively for weight gain and blood and livers were harvested at termination. The extent of liver injury was examined by histopathology as well as by liver and serum biochemistry. The expression of lipid metabolism, inflammation and fibrogenesis-related molecules was examined by quantitative reverse transcription PCR (Q-PCR) and immunofluorescence staining.

Results:

HFD significantly increased total body weight, triglyceride and cholesterol, whereas alcohol increased liver weight. Alcohol+HFD in combination produced maximum hepatic steatosis, increased micro- and macro-vesicular lipid droplets, increased de novo lipogenesis (steroid response-element binding protein 1 (SREBP-1) and stearoyl-CoA desaturase-1 (SCD-1)) and proliferation peroxisome activated receptor alpha (PPARα), and decreased fatty acid β-oxidation (Acyl-CoA oxidase 1 (ACOX1)). Alcohol+HFD treatment also increased the inflammation (CD45+, CD68+, F4/80+ cells; tumour necrosis factor-alpha (TNF-α), F4/80 mRNAs) and fibrogenesis (vimentin+ activated stellate cells, collagen 1 (Col1) production, transforming growth factor-beta (TGF-β) and Col-1 mRNAs) in mice livers.

Conclusions:

We report a novel mouse model with more severe liver injury than either alcohol or HFD alone recapitulating the human setting of intermittent alcohol drinking and HFD.

Differential protective effects of extra virgin olive oil and corn oil in liver injury: a proteomic study

Extra virgin olive oil (EVOO) presents benefits against chronic liver injury induced by hepatotoxins such as carbon tetrachloride (CCl4); however, the protective mechanisms remain unclear. In the present study, a two-dimensional gel based proteomic approach was constructed to explore the mechanisms. Rats are injected with CCl4 twice a week for 4 weeks to induce liver fibrosis, and were fed laboratory chow plus 20% (w/w) of either corn oil or EVOO over the entire experimental period. Histological staining, MDA assay and fibrogenesis marker gene analysis illustrate that the CCl4-treated animals fed EVOO have a lower fibrosis and lipid peroxidation level in the liver than the corn oil fed group. The proteomic study indicates that the protein expression of thioredoxin domain-containing protein 12, peroxiredoxin-1, thiosulphate sulphurtransferase, calcium-binding protein 1, Annexin A2 and heat shock cognate 71 kDa protein are higher in livers from EVOO-fed rats with the CCl4 treatment compared with those from rats fed with corn oil, whereas the expression of COQ9, cAMP-dependent protein kinase type I-alpha regulatory subunit, phenylalanine hydroxylase and glycerate kinase are lower. Our findings confirmed the benefits of EVOO against chronic liver injury, which may be attributable to the antioxidant effects, hepatocellular function regulation and hepatic metabolism modification effects of EVOO.

Osteopontin is an important mediator of alcoholic liver disease via hepatic stellate cell activation

AIM: To investigate over-expression of Osteopontin (OPN) pathway expression and mechanisms of action in human alcoholic liver disease (ALD), in vivo and in vitro acute alcohol models.

METHODS: OPN pathway was evaluated in livers from patients with progressive stages of human ALD and serum from drinkers with and without liver cirrhosis. In vitro stellate LX2 cells exposed to acute alcohol and in vivo in acute alcoholic steatosis mouse models were also investigated for OPN pathway expression and function. WT and OPN^-/- mice were administered an acute dose of alcohol and extent of liver injury was examined by histopathology and liver biochemistry after 16-24 h. The causative role of OPN was studied in OPN knockout animals and in vitro in stellate LX2 cells, utilizing siRNA, aptamer and neutralizing antibodies to block OPN and OPN pathway. OPN pathway expression and downstream functional consequences were measured for signaling by Western blotting, plasmin activation by spectrophotometric assays and cell migration by confocal imaging and quantitation.

RESULTS: OPN expression positively correlated with disease severity in patients with progressive stages of ALD. In vivo, associated with alcoholic steatosis, a single dose of acute alcohol significantly increased hepatic OPN mRNA and protein, and a cleaved OPN form in a dose dependent manner. OPN mRNA and secreted OPN also increased in parallel with activation of LX2 stellate cells within 4 h of a single dose of alcohol. Expression of OPN receptors, αvβ3-integrin and CD44, increased in human ALD, and in vivo and in vitro with alcohol administration. This was accompanied by downstream phosphorylation of Akt and Erk, increased mRNA expression of several fibrogenesis, fibrinolysis and extracellular matrix pathway genes, plasmin activation and hepatic stellate cell (HSC) migration. Inhibition of OPN and OPN-receptor mediated signaling partially inhibited alcohol-induced HSC activation, plasmin activity and cell migration.

CONCLUSION: OPN is a key mediator of the alcohol-induced effects on hepatic stellate cell functions and liver fibrogenesis.

Therapeutic potential of chinese herbal medicines in alcoholic liver disease

Alcoholic liver disease (ALD) is a complex chronic disease and is associated with a spectrum of liver injury ranging from steatosis and steatohepatitis to fibrosis and cirrhosis. Since effective therapies for ALD are still limited, Chinese herbal medicine is thought to be an important and alternative approach. This review focuses on the current scientific evidence of ALD by ten Chinese Materia Medica ( zhōng yào), including Salviae Miltiorrhizae Radix ( dān shēn), Notoginseng Radix ( sān qī), Lycii Fructus ( gǒu qǐ zǐ), Cnidii Fructus ( shé chuáng zǐ), Gentianae Radix ( lóng dǎn), Puerariae Radix ( gé gēn), Puerariae Flos ( gé huā), Magnoliae Officinalis Cortex ( hòu pò), Platycodonis Radix ( jié gěng), and Trigonellae Semen ( hú lú bā). Potential mechanisms of these herbal medicines in ALD are involved in amelioration of enhanced inflammation, reduction of hepatic oxidative stress and lipogenesis, and enhancement of intestinal permeability in alcohol-induced liver injury models in vitro and in vivo. Accordingly, the evidenced therapeutic potential suggests that these herbs are promising candidates for prevention and development of new drugs for ALD in the future.

Cardiovascular risk, lipidemic phenotype and steatosis. A comparative analysis of cirrhotic and non-cirrhotic liver disease due to varying etiology

BACKGROUND

Liver regulates lipid metabolism in health and disease states. Nevertheless, the entity of cardiovascular risk (CVR) resulting from dysregulation of lipid metabolism secondary to liver disease is poorly characterized.

AIM AND METHODS

To review, based on a PubMed literature search, the features and the determinants of serum lipid phenotype and its correlation with hepatic steatosis, insulin resistance (IR) and CVR across the wide spectrum of the most common chronic liver diseases due to different etiologies.

RESULTS

Alcoholic liver disease (ALD) is associated with steatosis, IR and a typical lipid profile. The relationship between alcohol intake, incident type 2 diabetes (T2D) and CVR describes a J-shaped curve. Non-alcoholic fatty liver disease (NAFLD), and probably nonalcoholic steatohepatitis (NASH) in particular, is associated with IR, atherogenic dyslipidemia and increased CVR independent of traditional risk factors. Moreover, NASH-cirrhosis and T2D contribute to increasing CVR in liver transplant recipients. HBV infection is generally free from IR, steatosis and CVR. HCV-associated dysmetabolic syndrome, featuring steatosis, hypocholesterolemia and IR, appears to be associated with substantially increased CVR. Hyperlipidemia is an almost universal finding in primary biliary cirrhosis, a condition typically spared from steatosis and associated with neither subclinical atherosclerosis nor excess CVR. Finally, little is known on CVR in patients with hepatocellular carcinoma.

CONCLUSIONS

CVR is increased in ALD, NAFLD and chronic HCV infection, all conditions featuring IR and steatosis. Therefore, irrespective of serum lipid phenotype, hepatic steatosis and IR may be major shared determinants in amplifying CVR in common liver disease due to varying etiology.

Annexin A2 is not a good biomarker for hepatocellular carcinoma in cirrhosis

In China, hepatocellular carcinoma (HCC) usually develops following a long history of chronic hepatitis B infection or cirrhosis. To evaluate the diagnostic role of annexin A2 (ANXA2), a possible tumor marker, in patients with hepatitis B virus (HBV)-related HCC, particularly those with a history of cirrhosis, the present study prospectively enrolled 87 patients with HBV-related HCC (with cirrhosis), 39 patients with HBV-related cirrhosis and 27 healthy controls. The expression levels of serum and tissue ANXA2 were determined using an enzyme-linked immunosorbent assay (ELISA) and immunohistochemical staining, respectively. The serum levels of ANXA2 were significantly elevated in the patients with HCC (median, 567.2 μg/ml; P=0.003) and cirrhosis (median, 414.8 μg/ml; P=0.011) compared with the healthy controls (median, 241.9 μg/ml). However, no significant differences were observed in the serum ANXA2 levels between the patients with HCC and those with cirrhosis. The immunohistochemical staining analysis showed that the healthy controls did not show positive staining, while the number of cases immunoreactive for ANXA2 steadily increased from the liver cirrhosis tissues (20/39, 51.3%) to the non-cancer (53/87, 60.9%) and cancer tissues (68/87, 78.2%). The cancer tissues exhibited a significantly higher ANXA2-positive rate compared with the non-cancer (P=0.013) and liver cirrhosis tissues (P=0.002). Furthermore, marked ANXA2 staining was more prevalent in the cancer tissues (16/87, 18.4%) than the non-cancer (4/87, 4.6%; P=0.004) and liver cirrhosis (1/39, 2.6%; P=0.034) tissues. The sensitivity, specificity and diagnostic accuracy of tissue ANXA2 for HCC in cirrhosis were 78.2, 42.1 and 56.8%, respectively. The ANXA2 expression levels in the serum and cancer tissues were not associated with tumor-free survival or patient survival following liver transplantation. Serum or tissue ANXA2 is not a good diagnostic marker for HCC in HBV-related cirrhosis and is not associated with prognosis.

Multiplex transcriptional analysis of paraffin-embedded liver needle biopsy from patients with liver fibrosis

Background

The possibility of extracting RNA and measuring RNA expression from paraffin sections can allow extensive investigations on stored paraffin samples obtained from diseased livers and could help with studies of the natural history of liver fibrosis and inflammation, and in particular, correlate basic mechanisms to clinical outcomes.

Results

To address this issue, a pilot study of multiplex gene expression using branched-chain DNA technology was conducted to directly measure mRNA expression in formalin-fixed paraffin-embedded needle biopsy samples of human liver. Twenty-five genes were selected for evaluation based on evidence obtained from human fibrotic liver, a rat BDL model and in vitro cultures of immortalized human hepatic stellate cells. The expression levels of these 25 genes were then correlated with liver fibrosis and inflammation activity scores. Statistical analysis revealed that three genes (COL3A1, KRT18, and TUBB) could separate fibrotic from non-fibrotic samples and that the expression of ten genes (ANXA2, TIMP1, CTGF, COL4A1, KRT18, COL1A1, COL3A1, ACTA2, TGFB1, LOXL2) were positively correlated with the level of liver inflammation activity.

Conclusion

This is the first report describing this multiplex technique for liver fibrosis and has provided the proof of concept of the suitability of RNA extracted from paraffin sections for investigating the modulation of a panel of proinflammatory and profibrogenic genes. This pilot study suggests that this technique will allow extensive investigations on paraffin samples from diseased livers and possibly from any other tissue. Using identical or other genes, this multiplex expression technique could be applied to samples obtained from extensive patient cohorts with stored paraffin samples in order to correlate gene expression with valuable clinically relevant information. This method could be used to provide a better understanding of the mechanisms of liver fibrosis and inflammation, its progression, and help development of new therapeutic approaches for this indication.

Rodent models of alcoholic liver disease: of mice and men

Alcoholic liver disease (ALD) is a major cause of acute and chronic liver disease worldwide. The progressive nature of ALD is well described; however, the complex interactions under which these pathologies evolve remain to be fully elucidated. Clinically there are no clear biomarkers or universally accepted, effective treatment strategies for ALD. Experimental models of ALD are an important component in identifying underlying mechanisms of alcohol-induced injury to develop better diagnostic markers, predictors of disease progression, and therapeutic targets to manage, halt, or reverse disease progression. Rodents remain the most accessible model for studying ALD pathology. Effective rodent models must mimic the natural history of ALD while allowing examination of complex interactions between multiple hepatic, and non-hepatic, cell types in the setting of altered metabolic or oxidative/nitrosative stress, inflammatory responses, and sensitivity to cytotoxic stress. Additionally, mode and duration of alcohol delivery influence hepatic response and present unique challenges in understanding disease pathology. This review provides an overview of rodent models of ALD, their strengths and weaknesses relative to human disease states, and provides insight of the potential to develop novel rodent models to simulate the course of human ALD.

Exacerbation of alcohol-induced oxidative stress in rats by polyunsaturated Fatty acids and iron load

The hypothesis that excessive intake of vegetable oil containing polyunsaturated fatty acids and iron load precipitate alcohol-induced liver damage was investigated in a rat model. In order to elucidate the mechanism underlying this synergism, the serum levels of iron, total protein, serum glutamate pyruvate transaminase, liver thiobarbituric acid reactive substances, and activities of antioxidant enzymes superoxide dismutase, catalase in liver of rats treated with alcohol, polyunsaturated fatty acids and iron per se and in combination were examined. Alcohol was fed to the rats at a level of 10-30% (blood alcohol was maintained between 150-350 mg/dl by using head space gas chromatography), polyunsaturated fatty acids at a level of 15% of diet and carbonyl iron 1.5-2% of diet per se and in combination to different groups for 30 days. Hepatotoxicity was assessed by measuring serum glutamate pyruvate transaminase, which was elevated and serum total protein, which was decreased significantly in rats fed with a combination of alcohol, polyunsaturated fatty acids and iron. It was also associated with increased lipid peroxidation and disruption of antioxidant defense in combination fed rats as compared to rats fed with alcohol or polyunsaturated fatty acids or iron. The present study revealed significant exacerbation of the alcohol-induced oxidative stress in presence of polyunsaturated fatty acids and iron.

Plasmin triggers a switch-like decrease in thrombospondin-dependent activation of TGF-β1

Transforming growth factor-β1 (TGF-β1) is a potent regulator of extracellular matrix production, wound healing, differentiation, and immune response, and is implicated in the progression of fibrotic diseases and cancer. Extracellular activation of TGF-β1 from its latent form provides spatiotemporal control over TGF-β1 signaling, but the current understanding of TGF-β1 activation does not emphasize cross talk between activators. Plasmin (PLS) and thrombospondin-1 (TSP1) have been studied individually as activators of TGF-β1, and in this work we used a systems-level approach with mathematical modeling and in vitro experiments to study the interplay between PLS and TSP1 in TGF-β1 activation. Simulations and steady-state analysis predicted a switch-like bistable transition between two levels of active TGF-β1, with an inverse correlation between PLS and TSP1. In particular, the model predicted that increasing PLS breaks a TSP1-TGF-β1 positive feedback loop and causes an unexpected net decrease in TGF-β1 activation. To test these predictions in vitro, we treated rat hepatocytes and hepatic stellate cells with PLS, which caused proteolytic cleavage of TSP1 and decreased activation of TGF-β1. The TGF-β1 activation levels showed a cooperative dose response, and a test of hysteresis in the cocultured cells validated that TGF-β1 activation is bistable. We conclude that switch-like behavior arises from natural competition between two distinct modes of TGF-β1 activation: a TSP1-mediated mode of high activation and a PLS-mediated mode of low activation. This switch suggests an explanation for the unexpected effects of the plasminogen activation system on TGF-β1 in fibrotic diseases in vivo, as well as novel prognostic and therapeutic approaches for diseases with TGF-β dysregulation.

High-density real-time PCR-based in vivo toxicogenomic screen to predict organ-specific toxicity

Toxicogenomics, based on the temporal effects of drugs on gene expression, is able to predict toxic effects earlier than traditional technologies by analyzing changes in genomic biomarkers that could precede subsequent protein translation and initiation of histological organ damage. In the present study our objective was to extend in vivo toxicogenomic screening from analyzing one or a few tissues to multiple organs, including heart, kidney, brain, liver and spleen. Nanocapillary quantitative real-time PCR (QRT-PCR) was used in the study, due to its higher throughput, sensitivity and reproducibility, and larger dynamic range compared to DNA microarray technologies. Based on previous data, 56 gene markers were selected coding for proteins with different functions, such as proteins for acute phase response, inflammation, oxidative stress, metabolic processes, heat-shock response, cell cycle/apoptosis regulation and enzymes which are involved in detoxification. Some of the marker genes are specific to certain organs, and some of them are general indicators of toxicity in multiple organs. Utility of the nanocapillary QRT-PCR platform was demonstrated by screening different references, as well as discovery of drug-like compounds for their gene expression profiles in different organs of treated mice in an acute experiment. For each compound, 896 QRT-PCR were done: four organs were used from each of the treated four animals to monitor the relative expression of 56 genes. Based on expression data of the discovery gene set of toxicology biomarkers the cardio- and nephrotoxicity of doxorubicin and sulfasalazin, the hepato- and nephrotoxicity of rotenone, dihydrocoumarin and aniline, and the liver toxicity of 2,4-diaminotoluene could be confirmed. The acute heart and kidney toxicity of the active metabolite SN-38 from its less toxic prodrug, irinotecan could be differentiated, and two novel gene markers for hormone replacement therapy were identified, namely fabp4 and pparg, which were down-regulated by estradiol treatment.

Pathogenesis of alcohol-induced liver disease: classical concepts and recent advances

Alcoholic liver disease (ALD) is a primary consequence of heavy and prolonged drinking. ALD contributes to the bulk of liver disease burden worldwide. Progression of ALD is a multifactorial and multistep process that includes many genetic and environmental risk factors. The molecular pathogenesis of ALD involves alcohol metabolism and secondary mechanisms such as oxidative stress, endotoxin, cytokines and immune regulators. The histopathological manifestation of ALD occurs as an outcome of complex but controlled interactions between hepatic cell types. Hepatic stellate cells (HSCs) are the key drivers of fibrogenesis, but transformation of hepatocytes to myofibroblastoids also implicate parenchymal cells as playing an active role in hepatic fibrogenesis. Recent discoveries indicate that lipogenesis during the early stages of ALD is a risk for advancement to cirrhosis. Other recently identified novel molecules and physiological/cell signaling pathways include fibrinolysis, osteopontin, transforming growth factor-β-SMAD and hedgehog signaling, and involvement of novel cytokines in hepatic fibrogenesis. The observation that ALD and non-alcoholic steatohepatitis share common pathways and genetic polymorphisms suggests operation of parallel pathogenic mechanisms. Future research involving genomics, epigenomics, deep sequencing and non-coding regulatory elements holds promise to identify novel diagnostic and therapeutic targets for ALD. There is also a need for adequate animal models to study pathogenic mechanisms at the molecular level and targeted therapy.

Advances in alcoholic liver disease

Alcoholic liver disease (ALD) remains a leading cause of death from liver disease in the United States. In studies from the Veterans Administration, patients with cirrhosis and superimposed alcoholic hepatitis had greater than 60% mortality over a 4-year period, with most of those deaths occurring in the first month. Thus, the prognosis for this disease is more ominous than for many common types of cancer (eg, breast, prostate, and colon). Moreover, ALD imposes a significant economic burden from lost wages, health care costs, and lost productivity. Unfortunately, there is still no Food and Drug Administration-approved or widely accepted drug therapy for any stage of ALD. Thus, a pressing need exists for a more detailed understanding of mechanisms of liver injury. This article reviews recent advances in mechanisms and therapy related to five major areas of direct relevance to ALD: oxidative stress; gut-liver axis and cytokine signaling; malnutrition; fibrin/clotting; and stellate cell activation/fibrosis. We also review why therapies related to these mechanisms have performed well in experimental animals and in vitro systems, but have not necessarily translated into effective therapy for humans with ALD.

The effect of Lycium barbarum polysaccharide on alcohol-induced oxidative stress in rats

The aim of this study was to investigate the effects of Lycium barbarum Polysaccharide (LBP) on alcohol-induced liver damage in rats. A total of 36 rats were divided into control, ethanol and ethanol + LBP groups. Rats in the ethanol group were fed 7 g ethanol/kg body weight by gastric infusion, three times a day, for 30 consecutive days, while rats in the control group received the same volume of physiological saline instead of ethanol, and rats in ethanol + LBP group were fed both ethanol (7 g/kg body weight) and LBP (300 mg/Kg body weight/day). Alcoholic liver injury was examined by serum ALT and AST activities, alcoholic fatty liver was assessed by lipid levels, and oxidative stress was evaluated by SOD, CAT, GSH-Px, GSH and MDA assays. In the ethanol group, a significant elevation of enzymes and lipid in serum, increased MDA level and depletion of SOD, CAT, GSH-Px and GSH in liver were observed. LBP administration significantly ameliorated liver injury, prevented the progression of alcohol-induced fatty liver, and improved the antioxidant functions when compared with the ethanol group. Histopathological examination of rat liver revealed that LBP administration protected liver cells from the damage induced by ethanol. The results suggest that LBP is a promising agent to protect the liver from hepatotoxicity and fatty liver induced by ethanol intake.

Plasma membrane proteome analysis of the early effect of alcohol on liver: implications for alcoholic liver disease

In humans, the over-consumption of alcohol can lead to serious liver disease. To examine the early effects of alcohol on liver disease, rats were given sufficient ethanol to develop liver cirrhosis. Rats before the onset of fibrosis were studied in this work. Plasma membranes (PM) of liver were extracted by twice sucrose density gradient centrifugation. The proteome profiles of PM from ethanol-treated rats and the controls were analyzed using two-dimensional gel electrophoresis (2-DE) and isobaric tag for relative and absolute quantitation (iTRAQ) technology. Ethanol treatment altered the amount of 15 different liver proteins: 10 of them were detected by 2-DE and 5 by iTRAQ. Keratin 8 was detected by both methods. Gene ontology analysis of these differentially detected proteins indicated that most of them were involved in important cell functions such as binding activity (including ion, DNA, ATP binding, etc.), cell structure, or enzyme activity. Among these, annexin A2, keratin 8, and keratin 18 were further verified using western blot analysis and annexin A2 was verified by immunohistochemistry. Our results suggested that alcohol has the potential to affect cell structure, adhesion and enzyme activity by altering expression levels of several relevant proteins in the PM. To the best of our knowledge, this is the first time to study the effect of alcohol on the liver PM proteome and it might be helpful for understanding the possible mechanisms of alcohol-induced liver disease.

Laboratory models available to study alcohol-induced organ damage and immune variations: choosing the appropriate model

The morbidity and mortality resulting from alcohol-related diseases globally impose a substantive cost to society. To minimize the financial burden on society and improve the quality of life for individuals suffering from the ill effects of alcohol abuse, substantial research in the alcohol field is focused on understanding the mechanisms by which alcohol-related diseases develop and progress. Since ethical concerns and inherent difficulties limit the amount of alcohol abuse research that can be performed in humans, most studies are performed in laboratory animals. This article summarizes the various laboratory models of alcohol abuse that are currently available and are used to study the mechanisms by which alcohol abuse induces organ damage and immune defects. The strengths and weaknesses of each of the models are discussed. Integrated into the review are the presentations that were made in the symposium "Methods of Ethanol Application in Alcohol Model-How Long is Long Enough" at the joint 2008 Research Society on Alcoholism (RSA) and International Society for Biomedical Research on Alcoholism (ISBRA) meeting, Washington, DC, emphasizing the importance not only of selecting the most appropriate laboratory alcohol model to address the specific goals of a project but also of ensuring that the findings can be extrapolated to alcohol-induced diseases in humans.

Plasma levels of fibrinolytic proteins and the risk of myocardial infarction in men

Hypofibrinolysis as measured with overall clot lysis assays is associated with risk of arterial thrombosis. Individual components of the fibrinolytic system, however, have not been studied extensively in relation to arterial disease, or results of studies were inconsistent. The relation between plasminogen and α2-antiplasmin levels and cardiovascular risk factors and the association between plasminogen, α2-antiplasmin, tissue-plasminogen activator (t-PA), and plasminogen activator inhibitor-1 (PAI-1) and risk of myocardial infarction was investigated in the Study of Myocardial Infarctions Leiden (555 men with a first myocardial infarction and 635 controls). α2-antiplasmin was associated with age and lipid levels, whereas plasminogen correlated with lipids, C-reactive protein, and smoking. Increased levels of all fibrinolytic factors were associated with myocardial infarction. Age-adjusted odds ratios (ORs; 95% confidence interval) for quartile 4 compared with 1 were 1.7 (1.2-2.3) for plasminogen, 1.9 (1.3-2.6) for α2-antiplasmin, 1.7 (1.2-2.3) for t-PA, and 1.7 (1.2-2.4) for PAI-1. After adjusting for cardiovascular risk factors, only α2-antiplasmin levels remained associated with risk (OR, 1.4; [1.0-2.0]). t-PA and PAI-1 levels predominantly reflected lipid levels, whereas plasminogen reflected the inflammatory state. Concluding, elevated α2-antiplasmin levels are independently associated with risk of myocardial infarction. t-PA, PAI-1, and plasminogen levels appear to reflect other cardiovascular risk factors.

Subcellular proteome analysis unraveled annexin A2 related to immune liver fibrosis

It is important to study the mechanism of liver fibrogenesis, and find new non-invasive biomarkers. In this study, we used subcellular proteomic technology to study the plasma membrane (PM) proteins related to immune liver fibrosis and search for new non-invasive biomarkers. A rat liver fibrosis model was induced by pig serum injection. The liver fibrogenesis from stage (S) S0-1, S2, S3-4, and S4 was detected by Masson staining and HE staining in this rat model after 2, 4, 6, and 8 weeks of treatment. The liver PM was enriched and analyzed using subcellular proteomic technology. The differentially expressed proteins were verified by Western blotting, immunohistochemistry, and ELISA. PM with 149-fold purification was obtained and 22 differentially expressed proteins were identified. Of which, annexin A2 (ANXA2) was detected to be increased obviously in S4 compared with S0-1, and verified by Western blotting of rat liver tissue and immunohistochemistry of rat and human liver tissue. The expression of ANXA2 in human plasma with S1-2 was also found to be up-regulated for 1.4-fold than that in S0. Furthermore, ANXA2 was detected to translocate from nuclear membrane and cytosol to PM as HBV stimulation through immunocytochemical analysis in vitro. This study identified 22 differentially expressed proteins related to liver fibrosis, and verified a potential biomarker (ANXA2) for non-invasive diagnosis of immune liver fibrosis. To our knowledge, it was the first time to dynamically study the proteins related to liver fibrosis and select biomarkers for liver fibrosis diagnosis through PM proteome research.

Alcohol, signaling, and ECM turnover

Alcohol is recognized as a direct hepatotoxin, but the precise molecular pathways that are important for the initiation and progression of alcohol-induced tissue injury are not completely understood. The current understanding of alcohol toxicity to organs suggests that alcohol initiates injury by generation of oxidative and nonoxidative ethanol metabolites and via translocation of gut-derived endotoxin. These processes lead to cellular injury and stimulation of the inflammatory responses mediated through a variety of molecules. With continuing alcohol abuse, the injury progresses through impairment of tissue regeneration and extracellular matrix (ECM) turnover, leading to fibrogenesis and cirrhosis. Several cell types are involved in this process, the predominant being stellate cells, macrophages, and parenchymal cells. In response to alcohol, growth factors and cytokines activate many signaling cascades that regulate fibrogenesis. This mini-review brings together research focusing on the underlying mechanisms of alcohol-mediated injury in a number of organs. It highlights the various processes and molecules that are likely involved in inflammation, immune modulation, susceptibility to infection, ECM turnover and fibrogenesis in the liver, pancreas, and lung triggered by alcohol abuse.

Compensatory role of inducible annexin A2 for impaired biliary epithelial anion-exchange activity of inflammatory cholangiopathy

The peribiliary inflammation of cholangiopathy affects the physiological properties of biliary epithelial cells (cholangiocyte), including bicarbonate-rich ductular secretion. We revealed the upregulation of annexin A2 (ANXA2) in cholangiocytes in primary biliary cirrhosis (PBC) by a proteomics approach and evaluated its physiological significance. Global protein expression profiles of a normal human cholangiocyte line (H69) in response to interferon-gamma (IFNgamma) were obtained by two-dimensional electrophoresis followed by MALDI-TOF-MS. Histological expression patterns of the identified molecules in PBC liver were confirmed by immunostaining. H69 cells stably transfected with doxycyclin-inducible ANXA2 were subjected to physiological evaluation. Recovery of the intracellular pH after acute alkalinization was measured consecutively by a pH indicator with a specific inhibitor of anion exchanger (AE), 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS). Protein kinase-C (PKC) activation was measured by PepTag Assay and immunoblotting. Twenty spots that included ANXA2 were identified as IFNgamma-responsive molecules. Cholangiocytes of PBC liver were decorated by the unique membranous overexpression of ANXA2. Apical ANXA2 of small ducts of PBC was directly correlated with the clinical cholestatic markers and transaminases. Controlled induction of ANXA2 resulted in significant increase of the DIDS-inhibitory fraction of AE activity of H69, which was accompanied by modulation of PKC activity. We, therefore, identified ANXA2 as an IFNgamma-inducible gene in cholangiocytes that could serve as a potential histological marker of inflammatory cholangiopathy, including PBC. We conclude that inducible ANXA2 expression in cholangiocytes may play a compensatory role for the impaired AE activity of cholangiocytes in PBC in terms of bicarbonate-rich ductular secretion and bile formation through modulation of the PKC activity.

Hepatoprotective activity of polyherbal formulation (Normeta) in oxidative stress induced by alcohol, polyunsaturated fatty acids and iron in rats

In recent years, oxidative stress has been implicated in the pathophysiology of a large number of diseases or disorders which are initiated and/or exacerbated by pro-oxidants such as various drugs including alcohol and food additives. The present study was carried out to evaluate the effects of oral treatment with polyherbal formulation Normeta (2 ml and 4 ml/kg) on hepatic damage induced by alcohol 10-30% (blood alcohol was maintained at levels between 150 and 350 mg/dl), thermally oxidized oil (polyunsaturated fatty acids) (15% of diet) and carbonyl iron (1.5-2% of diet) for 30 days in rats. In vitro studies with 1, 1-Diphenyl, 2-Picrylhydrazyl (DPPH), Nitric oxide and Ferric chloride (Fe(+3) ions) showed that Normeta possesses antioxidant and metal chelating activity. Alcohol, polyunsaturated fatty acids and iron feeding produced an increase in serum levels of iron, serum glutamate pyruvate transaminase and decrease in serum proteins. It was also associated with elevated lipid peroxidation (thiobarbituric acid reactive substances) and disruption of antioxidant defence mechanism in liver, decreased body weight and increased liver to body weight ratio. Oral administration of Normeta along with alcohol, polyunsaturated fatty acids and iron decreased the serum iron, serum glutamate pyruvate transaminase levels and increased serum protein levels. The levels of liver thiobarbituric acid reactive substances were decreased and the activities of antioxidant enzymes superoxide dismutase and catalase were increased. Improvement in body weight and liver to body weight ratio was also observed. The effects of Normeta on physico-metabolic parameters were comparable with silymarin. This indicates that Normeta has favourable effect in bringing down the severity of hepatotoxicity.

"Second hit" models of alcoholic liver disease

Alcoholic liver disease (ALD) is a lifestyle disease with its pathogenesis and individual predisposition governed by gene-environment interactions. Based on the "second hit" or "multiple hits" hypothesis, patients are predisposed to progressive ALD when a magic combination of gene and environmental interactions exists. Reproduction of second or multiple hits in animal models serves to test a combination and to gain mechanistic insights into synergism achieved by such combination. Numerous environmental factors have been incorporated into animal models, largely classified into nutritional, xenobiotic/pharmacologic, hemodynamic, and viral groups. A loss or gain of function genetic model has become a popular experimental approach to test the role of a gene as a second hit. Future research will need to test more subtle or natural hits combined with excessive alcohol intake to test multiple hits in the genesis of ALD. Additionally, animal models of comorbidities are urgently needed particularly for synergistic liver disease and oncogenesis caused by alcohol, obesity, and hepatitis virus.