Model Of Alcoholic Liver Injury Research Articles

MTORC1 Inhibition Reduces ER Stress and Ameliorates Alcoholic Liver Injury

Hyperactivation of mammalian target of rapamycin complex 1 (mTORC1) and endoplasmic reticulum (ER) stress promote hepatic lipid accumulation and insulin resistance. To elucidate the role of mTORC1 in the alcoholic liver disease (ALD), we examined mTORC1 activation and adaptive unfolded protein response (UPR) mechanisms in chronic plus binge ethanol feeding (CB) murine model of alcoholic liver injury. CB resulted in hepatic steatosis, elevation of serum alanine aminotransferase levels, exacerbation of cell apoptosis as indicated as caspase 3 cleavage and poly ADP-ribose polymerase activation. In livers of CB mice, selective UPR genes were upregulated, as evidenced by X-box binding protein splicing, phosphorylation of eIF2α and increased levels of ER chaperone. Furthermore, CB led to defective adaption to prolonged ER stress for ER stress-mediated apoptosis was activated in liver. Similar ER stress responses were achieved/attenuated in mice after challenging with tunicamycin/4-PBA, an ER stress inducer/inhibitor. The steatotic changes were also attributed to lipids accumulation as reflected by sterol regulatory element-binding protein 1 and peroxisome proliferator-activated receptor alpha. Importantly, the activity of mTORC1, as indicated by phosphorylation of S6K1 and 4E-BP1, was increased in CB mice. mTORC1 inhibition by Deptor overexpression or rapamycin injection can restore hepatic ER homeostasis, inhibited lipogenesis, and reduced fatty liver. Specific signaling pathway regulated by mTORC1 was also determined in S6K1 dominant negative CB mice. Therefore, hepatic activation of mTORC1 may play a causal role in ER stress and steatosis related to ALD.

Effect of blueberry on hepatic expression of TLR4 in a rat model of alcoholic liver injury

Effect of blueberry on hepatic expression of TLR4 in a rat model of alcoholic liver injury

English

The aim of study is to detect the effects and relevant mechanisms of oxysophoridine on alcoholic hepatic injury in mice. Sixty male Institute of Cancer Research (ICR) mice were randomly divided into a normal control group, an alcoholic liver injury model group, a positive control (tiopronin) group and an oxysophoridine (250, 125, 62.5 mg/kg) group. Consecutive interventions were conducted on each group for 10 days; specimens were obtained according to requirements of the testing indicators 16 h after the last drug administration. The protective effects were evaluated by biochemical parameters including serum aspartate transaminase (AST), alanine transferase (ALT), reduced glutathione (GPx), liver malondialdehyde (MDA) and superoxide dismutase (SOD). The pathological changes of the liver in microstructure and ultrastructure were observed. A decreased level of serum ALT, AST activity and liver MDA content with increased liver SOD, GPx activity (P<0.05) were observed (P<0.05) in the oxysophoridine group compared with the alcoholic liver injury model group, in which elevated serum ALT and AST activity were recorded, along with a marked increase of liver MDA (P<0.05), decrease of liver SOD and GPx (P<0.05). The following changes of the liver were observed in the model group: Blurred contour of the hepatic lobule with punctated or focal necrosis in partial liver cells, multiple intracellular microvesicular steatosis, with lipid droplets formed in the cytoplasm, marked swelling of hepatocytes and disarrangement of hepatic cords, swelling of mitochondria, with disappeared or broken cristae, enlarged endoplasmic reticulum and condensed chromatin. Compared with the model group, a decrease in pathological changes of various degrees was observed in the oxysophoridine group at various doses. The result indicates that oxysophoridine prevents alcoholic liver damage in mice and the protective effect may be associated with anti-oxidative stress.   Key words:  Alcohol, oxysophoridine, oxidative stress, antioxidants.

Mouse model of chronic and binge ethanol feeding (the NIAAA model).

Chronic alcohol consumption is a leading cause of chronic liver disease worldwide, leading to cirrhosis and hepatocellular carcinoma. Currently, the most widely used model for alcoholic liver injury is ad libitum feeding with the Lieber-DeCarli liquid diet containing ethanol for 4-6 weeks; however, this model, without the addition of a secondary insult, only induces mild steatosis, slight elevation of serum alanine transaminase (ALT) and little or no inflammation. Here we describe a simple mouse model of alcoholic liver injury by chronic ethanol feeding (10-d ad libitum oral feeding with the Lieber-DeCarli ethanol liquid diet) plus a single binge ethanol feeding. This protocol for chronic-plus-single-binge ethanol feeding synergistically induces liver injury, inflammation and fatty liver, which mimics acute-on-chronic alcoholic liver injury in patients. This feeding protocol can also be extended to chronic feeding for longer periods of time up to 8 weeks plus single or multiple binges. Chronic-binge ethanol feeding leads to high blood alcohol levels; thus, this simple model will be very useful for the study of alcoholic liver disease (ALD) and of other organs damaged by alcohol consumption.

Association of the cannabinoid receptor 2 (CB2) Gln63Arg polymorphism with indices of liver damage in obese children: An alternative way to highlight the CB2 hepatoprotective properties

We thank Rossi and colleagues for their interest in our experimental findings delineating the impact of CB2 receptors in experimental models of liver injury. We reported recently that the hepatic cannabinoid receptor 2 (CB2) displays beneficial hepatoprotective and antifibrogenic properties.1, 2 However, as stressed by Rossi and colleagues, we also demonstrated that treatment of obese mice with the CB2-selective agonist JWH-133 enhances insulin resistance and steatosis.3 Deleterious effects of CB2 agonism in obese mice were attributed to a proinflammatory effect of adipose tissue CB2 receptors.3 However, our recent findings in a model of alcoholic liver injury indicate that stimulation of hepatic CB2 receptors reduces the development of fatty liver.4 Altogether, our experimental data demonstrate the protective effects of hepatic CB2 receptors against liver injury, steatosis, and fibrosis. In their cohort study of over 400 obese children, Rossi and colleagues show a positive correlation between the presence of a CB2 variant with reduced activity, as assessed in culture studies, and the degree of liver injury estimated by serum aminotransferase levels. These interesting findings constitute the first evidence supporting the clinical relevance of hepatoprotective effects of CB2 receptors. Further studies should be conducted to examine the impact of CB2 polymorphism on the severity of liver lesions (steatosis, necroinflammation, and fibrosis) in patients with nonalcoholic steatohepatitis. Sophie Lotersztajn* , Fatima Teixeira-Clerc*, Vanessa Deveaux*, Sylvie Manin*, Ariane Mallat* , * INSERM U955, Créteil France, Université Paris Est, Créteil France

Paeonol, the main active principles of Paeonia moutan, ameliorates alcoholic steatohepatitis in mice

Aim of study Paeonol, a major phenolic component of Moutan Cortex, is traditionally used as a Chinese herbal medicine in various diseases including hepatitis. Evidence shows that paeonol has anti-inflammatory, anti-tumor, and anti-atherosclerosis effects. However, the effect of paeonol on alcoholic liver injury remains obscure. The present investigation was designed to determine the effects of paeonol on alcohol-induced hepatic injury in mice. Materials and methods The degree of alcoholic liver injury was evaluated biochemically by measuring serum markers and pathological examination. Real-time PCR and ELISA methods were used to check the expression of cytokines. Western blotting was used to check CYP 450 expression. Results Treatment with paeonol significantly attenuated the level of serum aminotransferase, reduced the severe extent of hepatic cell damage, steatosis, and the infiltration of inflammatory cells in a model of alcoholic liver injury ( P < 0.05). Interestingly, paeonol markedly decreased hepatic mRNA expression of lipogenic genes ( P < 0.05) while had no effect on protein expression of hepatic CYP2E1. Furthermore, paeonol significantly decreased serum and tissue inflammatory cytokine levels, tissue lipid peroxidation, neutrophil infiltration and inhibited the apoptosis of hepatocytes ( P < 0.05). Kupffer cells isolated from ethanol-fed mice produced high amounts of tumor necrosis factor alpha, whereas Kupffer cells from paeonol treatment ethanol-fed mice produced less tumor necrosis factor alpha ( P < 0.05). Conclusions These findings suggest that paeonol may represent a novel, protective strategy against alcoholic liver injury by attenuating hepatic steatosis, inflammatory response and apoptosis.

Initiation of alcoholic fatty liver and hepatic inflammation with a specific recall immune response in alcohol-consuming C57Bl/6 mice.

Whether immunological responses are involved in initiation and progression of alcoholic liver disease is unclear. We describe a mouse model of alcoholic liver injury characterized by steatosis and hepatic inflammation initiated by a recall immune response. Mice immune to Listeria monocytogenes fed a liquid diet containing ethanol and challenged with viable bacteria developed steatosis within 24 h and, at a later time, elevated serum alanine aminotransferase levels, indicating more liver damage in this group. Listeria antigen also induced steatosis and increased serum alanine aminotransferase levels in immune ethanol-consuming mice. The production of tumour necrosis factor by a recall immune response in this model is a major, but not the only, component in initiation of alcoholic liver disease.

Models of alcoholic liver disease in rodents: a critical evaluation.

This article represents the proceedings of a workshop at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were J. Christian Bode and Hiroshi Fukui. The presentations were (1) Essentials and the course of the pathological spectrum of alcoholic liver disease in humans, by P. de la M. Hall; (2) Lieber-DeCarli liquid diet for alcohol-induced liver injury in rats, by C. S. Lieber and L. M. DeCarli; (3) Tsukamoto-French model of alcoholic liver injury, by S. W. French; (4) Animal models to study endotoxin-ethanol interactions, by K. O. Lindros and H. Järveläinen; and (5) Jejunoileal bypass operation in rats-A model for alcohol-induced liver injury? by Christiane Bode, Alexandr Parlesak, and J. Christian Bode.

Models of Alcoholic Liver Disease in Rodents: A Critical Evaluation

This article represents the proceedings of a workshop at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were J. Christian Bode and Hiroshi Fukui. The presentations were (1) Essentials and the course of the pathological spectrum of alcoholic liver disease in humans, by P. de la M. Hall; (2) Lieber‐DeCarli liquid diet for alcohol‐induced liver injury in rats, by C. S. Lieber and L. M. DeCarli; (3) Tsukamoto‐French model of alcoholic liver injury, by S. W. French; (4) Animal models to study endotoxin‐ethanol interactions, by K. O. Lindros and H. Järveläinen; and (5) Jejunoileal bypass operation in rats—A model for alcohol‐induced liver injury? by Christiane Bode, Alexandr Parlesak, and J. Christian Bode.

Iron primes hepatic macrophages for NF-kappaB activation in alcoholic liver injury.

NF-kappaB activation induced by lipopolysaccharide (LPS) in cultured hepatic macrophages (HM) may be abrogated by pretreatment of cells with a lipophilic iron chelator, 1,2-dimethyl-3-hydroxypyrid-4-one (L1, deferiprone), suggesting a role for iron in this molecular event [M. Lin, M., R. A. Rippe, O. Niemelä, G. Brittenham, and H. Tsukamoto, Am. J. Physiol. 272 (Gastrointest. Liver Physiol. 35): G1355-G1364, 1997]. To ascertain the relevance in vivo of this hypothesis, HM from an experimental model of alcoholic liver injury were examined for the relationship between nuclear factor (NF)-kappaB activation and iron storage. HM showed a significant increase in nonheme iron concentration (+70%), accompanied by enhanced generation of electron paramagnetic resonance-detected radicals (+200%), NF-kappaB activation (+100%), and tumor necrosis factor-alpha (+150%) and macrophage inflammatory protein-1 (+280%) mRNA induction. Treatment of the cells ex vivo with L1 normalized all these parameters. HM content of ferritin protein, ferritin L chain mRNA, and hemeoxygenase-1 mRNA and splenic content of nonheme iron were increased, suggesting enhanced heme turnover as a cause of the increased iron storage and NF-kappaB activation. To test this possibility, increased iron content in HM was reproduced in vitro by phagocytosis of heat-treated red blood cells. Treatment caused a 40% increase in nonheme iron concentration and accentuated LPS-induced NF-kappaB activation twofold. Both effects could be abolished by pretreatment of cells with zinc protoporphyrin, a hemeoxygenase inhibitor. To extend this observation, animals were splenectomized before 9-wk alcohol feeding. Splenectomy resulted in further increments in HM nonheme iron storage (+60%) and NF-kappaB activation (+90%) and mononuclear cell infiltration (+450%), particularly around the iron-loaded HM in alcohol-fed animals. These results support the pivotal role of heme-derived iron in priming HM for NF-kappaB activation and expression of proinflammatory genes in alcoholic liver injury.

Glutamate-induced neurotoxicity and intracellular calcium homeostasis in neurons

In the present study, we aimed to investigate the therapeutic effect of Vitexin on inhibiting ethanol-induced liver damage and explore the underling mechanism. In vitro, the injury was induced in LO2 cell by 100 mM ethanol. Cell viability, AST, oxidative stress, inflammation, apoptosis rate, and related gene and protein expressions were assessed. Alcoholic liver injury model was made by intragastric infusion of alcohol for 4 weeks on male KM mice. Liver index, AST, ALT, TC, TG, TP, TBIL in serum and liver pathology were evaluated. Meanwhile, the level of SOD, MDA and TNF-α also were detected by Kits. Quantitative RT-PCR and Western blotting analysis the Sirt1/p53 pathway related gene and protein expressions. In vitro, Vitexin restored cytoactive and inhibited the releasing of AST induced by ethanol in LO2 cell. Vitexin treatment significantly suppressed the elevation of aminotransferase, blood lipid, UA in mice. Vitexin ameliorated liver pathological changes induced by ethanol. Vitexin supplement restored the decrease of Sirt1/Bcl-2 expression, restrained the elevation of caspase3, cleaved caspse-3, p53 and ac-p53 expression in vivo and in vitro. Vitexin has a protective effect against ethanol-induced liver damage, and the underlying mechanism is probably through Sirt1/p53 mediated mitochondrial apoptotic pathway.

Elevated plasma levels of hyaluronic acid indicate endothelial cell dysfunction in the initial stages of alcoholic liver disease in the rat

Background/Aims: We used the intragastric feeding rat model for alcoholic liver disease to evaluate the relationship between morphologic and functional indicators of endothelial cell dysfunction. Methods: Twelve groups of rats (4–5 rats/group) were fed the following diets: saturated fat and dextrose (SD), saturated fat and ethanol (SE), corn oil and dextrose (CD), corn oil and ethanol (CE). Four of the 12 groups were sacrificed at 2 weeks, four groups at 4 weeks and remaining four groups at 8 weeks. The following were evaluated at sacrifice: pathologic changes in the liver, endothelial cell proliferation using a monoclonal antibody to proliferating cell nuclear antigen, factor VIII-related antigen staining of endothelial cells in liver, plasma endotoxin, hyaluronan and prostaglandin F 2α. Results: Only CE rats at 4 and 8 weeks showed pathologic changes. The plasma levels of HA were significantly higher in the CE groups compared to the other groups at all time intervals studied. In the CE rats, a significant correlation was obtained between plasma endotoxin and hyaluronan ( r=0.84, p<0.01). Endotoxin levels also correlated significantly with the number of G 1/S arrested hepatic sinusoidal endothelial cells ( r=0.61, p<0.05). A role for prostaglandin F 2α, in causing endothelial dysfunction, was suggested by a significant correlation between plasma hyaluronan and prostaglandin F 2α levels ( r=0.95, p<0.01). Positive factor VIII related antigen staining of hepatic endothelial cells was seen in rats with high plasma hyaluronan levels. Conclusion: We propose that endotoxin, mediating part of its effect through prostaglandin F 2α, plays a role in hepatic sinusoidal endothelial cell G 1/S arrest. This morphologic change, associated with increased plasma hyaluronan levels, precedes capillarization in this model of alcoholic liver injury.

Plasma amino acid abnormalities in the alcoholic: Respective role of alcohol, nutrition, and liver injury

Plasma amino acid abnormalities are common in alcoholics, but the respective role of alcoholism, nutrition, and liver injury in producing these abnormalities is unknown. To elucidate this question, amino acids were measured in 56 alcoholics and 32 nonalcoholics with liver disease, and in an experimental model of alcoholic liver injury in the baboon. Dietary protein deficiency depressed branched-chain amino acids with a tendency to decreased α-amino-n-butyric acid. By contrast, chronic alcoholic consumption selectively increased these amino acids both in short term (2 to 4 weeks) studies in human beings and in 1 to 4-year studies in baboons. Moderate liver injury had no significant effects on these amino acids whereas advanced cirrhosis depressed branched-chain amino acids. Thus, plasma branched-chain amino acids and α-amino-n-butyric acid in the alcoholic are affected by at least three variables: dietary protein deficiency and advanced cirrhosis which tend to decrease these amino acids, and chronic alcohol consumption which tends to increase them.