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Background Our previous work showed that binge drinking in the rat induced hepatic steatosis which correlated with reduced expression of AMP-activated protein kinase ( AMPK). In this study, we used the rat model to investigate the role of adiponectin (Adip), sirtuin 1 ( SIRT1), AMPK, and lipin 1 ( LIP 1) signaling, a central controlling pathway of lipid metabolism in hepatic steatosis. Methods The serum Adip and tumor necrosis factor-alpha ( TNF- α) as well as liver Adip receptors (AdipoR1 and AdipoR2) SIRT1, AMPK, phosphorylated AMPK (p- AMPK), sterol regulatory element-binding proteins ( SREBPs), acetyl-CoA carboxylase ( ACC), LIP 1, lipocalin-2 ( LCN2), and serum amyloid A1 were assessed in the rat model where 16 weeks of gavaged alcohol were administered. Results In this model of ethanol (EtOH) administration, hepatic steatosis, necrosis, as well as inflammation were increased over the 16-week period. The level of TNF- α in the serum was increased while the Adip content decreased significantly, and there was an inverse relationship between the content of TNF- α and Adip. The mRNA and protein expression of AdipoR2, SIRT1, and AMPK was suppressed by EtOH in the rats' hepatic tissue. Additionally, EtOH significantly decreased p- AMPK by 90% over the 16-week period. In parallel, there was a 2.53- and 1.82-fold increase of lipogenic genes SREBP1c and ACC, and a 3.22- and 4.12-fold increase of LIP 1 and LIP 1 β mRNA expression, respectively, in the hepatic tissue of the rats. Conclusions Our present observations demonstrate that the impaired Adip- SIRT1- AMPK signaling pathway contributes, at least in part, to the development of alcoholic fatty liver disease in EtOH binge rats. [ABSTRACT FROM AUTHOR]

Background Alcoholic liver disease (ALD) continues to be a major cause of morbidity worldwide. The exact mechanisms for ALD pathogenesis are not fully understood. There is currently no known available drug for ALD. Previous studies have suggested that ethanol (EtOH)-induced hepatic insulin resistance, through the inhibition of adenosine monophosphate-activated protein kinase (AMPK) and the expression of adiponectin as well as downstream enzymes, contribute to the development of ALD. This study was to determine the effects of EtOH on AMPK activity as well as the protective effect of metformin. Methods Forty male Wistar rats weighing 200 ± 20 g were randomized into 4 groups ( n = 10) as follows: A = control group-rats received rodent chow; B = control + metformin group-rats received metformin (200 mg/kg/d intragastrically [IG]) at 21:00; C = EtOH group-rats were gavaged with alcohol of gradually increasing concentrations (30 to 60%, 5 to 9 g/kg/d) twice a day (9:00 and 16:00); D = EtOH + metformin group-rats received the same amount of EtOH as the rats in group C, and in addition received metformin (200 mg/kg/d IG) at 21:00. After 16 weeks, blood and liver samples were collected for further study. Results Chronic EtOH consumption led to liver injury both histologically and biochemically accompanied by insulin resistance, reduced AMPK activity, and dysregulation of downstream enzymes. Decreased levels of circulating adiponectin and decreased expression of proliferator-activated receptor gamma coactivator-1α ( PGC-1α) and peroxisome proliferator-activated receptors-α ( PPAR-α) in the hepatic tissue were observed. Treatment with metformin attenuated the severity of liver injury, restored AMPK activity and normalized the expression of acetyl-CoA carboxylase and fatty acid synthase. In addition, metformin also increased the circulating adiponectin and liver adiponectin receptor 2 expression. Furthermore, PGC-1α and PPAR-α activities were also restored. Conclusions EtOH exposure induces hepatic insulin resistance. Metformin improved insulin resistance and reversed liver injury through the activation of AMPK and normalized adiponectin signaling making metformin a promising drug for the treatment of ALD. [ABSTRACT FROM AUTHOR]

Background To investigate whether 'binge' and escalating alcohol exposure in the rat influences the development of pathological liver injury. Methods Time courses for the formation of eicosanoids by cyclooxygenase (COX), oxidative stress and nitrosative stress production, expression of hypoxia-inducible factor 1 (HIF-1), cytokines, hepatic tissue necroinflammation, and fibrosis were assessed in rats during 16 weeks of daily alcohol gavage. Results In this model of binge and escalating levels of alcohol, hepatic steatosis, necrosis, and inflammation as well as fibrosis were increased over the 16-week period. The levels of COX-2, oxidative stress, nitrosative stress, HIF-1, proinflammatory mediators ( tumor necrosis factor-α, interleukin 1β [IL-1β], IL-6), and procollagen-I were increased over the 16-week period. The content of IL-10 in rat serum increased at the end of 4 and 8 weeks but decreased thereafter and was significantly decreased at 12 and 16 weeks. Conclusions A rat model of alcoholic liver disease (ALD) with long-term binge and escalating ethanol exposure was developed. Our data support the hypothesis that enhanced eicosanoid production by COX, oxidative stress and nitrosative stress, HIF-1, and the imbalance between pro- and anti-inflammatory cytokines plays an important role in the pathogenesis of ALD. [ABSTRACT FROM AUTHOR]

Background Thromboxane levels are increased in rats fed ethanol ( Et OH), whereas thromboxane inhibitors reduce alcoholic liver injury. The aim of this study is to determine whether thromboxane inhibitors could attenuate the already established alcoholic liver injury. Methods Rats were fed Et OH and liquid diet for 6 weeks by intragastric infusion to induce liver injury after which EtOH was continued for 2 more weeks, and the rats were treated with either a thromboxane synthase inhibitor ( TXSI) or a thromboxane receptor antagonist ( TXRA). Liver pathology, lipid peroxidation, nuclear factor-kappa- B ( NF-κ B) activity, tumor necrosis factor-α ( TNF-α), cyclooxygenase-2 ( COX-2), and transforming growth factor-beta1 ( TGF-β1) were evaluated. Results Administration of fish oil and Et OH caused fatty liver, necrosis, inflammation and fibrosis accompanied by increased in lipid peroxidation, NF-κ B activity, and expression of TNF-α, COX-2, and TGF-β1. Treatment with the thromboxane inhibitors ameliorated a certain level of the pathological and biochemical abnormalities. In particular, TXSI in addition to reducing necrosis, inflammation and fibrosis also decrease the severity of fatty liver. Conclusions Thromboxane inhibitors attenuated the alcoholic liver injury, inflammation and fibrotic changes despite continued Et OH administration. Inhibition of the production of thromboxane by thromboxane inhibitor and receptor antagonists may be a useful treatment strategy in clinical alcoholic liver disease. [ABSTRACT FROM AUTHOR]

Background: Ethanol metabolism increases production of reactive oxygen species, including superoxide ( ) in the liver, resulting in significant oxidative stress, which causes cellular damage. Superoxide dismutase (SOD) is an antioxidant enzyme that converts superoxide to less toxic intermediates, preventing accumulation. Because the absence of SOD would confer less resistance to oxidative stress, we determined whether damage to hepatic proteolytic systems was greater in SOD−/− than in SOD+/+ mice after chronic ethanol feeding. Methods: Female wild-type (SOD+/+) and Cu/Zn-SOD knockout (SOD−/−) mice were pair-fed ethanol and control liquid diets for 24 days, after which liver injury was assessed. Results: Ethanol-fed SOD−/− mice had 4-fold higher blood ethanol, 2.8-fold higher alanine aminotransferase levels, 20% higher liver weight, a 1.4-fold rise in hepatic protein levels, and 35 to 70% higher levels of lipid peroxides than corresponding wild-type mice. While wild-type mice exhibited fatty liver after ethanol administration, SOD−/− mice showed no evidence of ethanol-induced steatosis, although triglyceride levels were elevated in both groups of knockout mice. Ethanol administration caused no significant change in proteasome activity, but caused lysosomal leakage in livers of SOD−/− mice but not in wild-type mice. Alcohol dehydrogenase activity was reduced by 50 to 60% in ethanol-fed SOD−/− mice compared with all other groups. Additionally, while ethanol administration induced cytochrome P450 2E1 (CYP2E1) activity in wild-type mice, it caused no such induction in SOD−/− mice. Unexpectedly, ethanol feeding significantly elevated total and mitochondrial levels of glutathione in SOD knockout mice compared with wild-type mice. Conclusion: Ethanol-fed SOD−/− mice exhibited lower alcohol dehydrogenase activity and lack of CYP2E1 inducibility, thereby causing decreased ethanol metabolism compared with wild-type mice. These and other atypical responses to ethanol, including the absence of ethanol-induced steatosis and enhanced glutathione levels, appear to be linked to enhanced oxidative stress due to lack of antioxidant enzyme capacity. [ABSTRACT FROM AUTHOR]

Reduced expression of endothelial nitric oxide synthase (eNOS) in chronic liver disease can reduce hepatic perfusion and accelerate fibrosis. The relationship between eNOS expression and liver fibrogenesis remains unclear. We investigated whetherl-arginine attenuated chronic liver fibrosis through eNOS expression. Chronic liver injury was induced by administration of carbon tetrachloride (CCl4) to mice for 8 weeks. 5-Methylisothiourea hemisulphate (SMT), an iNOS inhibitor, orl-arginine, a NOS substrate were injected subcutaneously. CCl4-induced hepatotoxicity, oxidative stress and accumulation of collagen were detected in the liver. The expression levels of inducible NOS (iNOS) and nuclear factor kappa-B (NF-κB) activity in the liver after CCl4 treatment were increased but eNOS expression and activator protein-1 (AP-1) activity were decreased. Both SMT andl-arginine effectively reduced CCl4 induced oxidative stress and collagen formation, butl-arginine showed a significantly greater suppression of collagen formation, iNOS expression and NF-κB activity.l-Arginine also restored the level of eNOS and AP-1 activity.l-Arginine was more effective than SMT in suppressing liver fibrosis.l-Arginine might improve NO production which facilitates hepatic blood flow and thus retards liver fibrogenesis. Our results showed that the reduced eNOS expression in CCl4-treated mice was reversed byl-arginine. Furthermore,l-arginine also reversed the reduced AP-1 activity, an eNOS promoter. [ABSTRACT FROM AUTHOR]

Background: The intragastric (IG) ethanol infusion model results in fatty liver, necrosis, inflammation and fibrosis. This model was utilized to study the pathogenesis of alcoholic liver disease (ALD). Disadvantages of the IG model include maintenance of the animals and equipment expense. To develop a voluntary feeding model for ALD, we took advantage of two important observations in the IG model: (i) female rats demonstrate greater severity of alcohol-induced liver injury than males and (ii) rats fed fish oil as a source of fatty acids develop more severe alcoholic liver injury than rats fed other fatty acids with ethanol. Methods: Female Wistar rats (205 to 220 g) were fed for 8 weeks a diet containing 8% ethanol, fish oil (30% of calories), protein, and dextrose. Pair-fed controls (FD) received dextrose in amounts isocaloric to ethanol. The following measurements were made: liver pathology [fatty liver (0 to 4), necrosis, inflammation and fibrosis by Sirius Red], endotoxin and alanine aminotransferase (ALT) in plasma, urine ethanol, lipid peroxidation, nuclear factor kappa-B (NF-κB) and mRNA levels for tumor necrosis factor-alpha (TNF-α), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). Protein levels for iNOS and nitrotyrosine were evaluated by immunohistochemistry and Western Blot analysis. Liver proteasome and cytochrome P450 2E1 activity and protein levels of asialoglycoprotein receptor (ASGPR) were also evaluated. In addition, mRNA levels of fibrogenic markers were assessed. Results: All animals lost weight for the initial 2 to 3 weeks but then gained weight until killing at 8 weeks. There was, however, a significant difference ( p < 0.05) in weight between the ethanol-fed (Etoh) and (FD) groups at the end of the experiment. The mean urine ethanol levels ranged between 190 and 240 mg/dl. The severity of pathological changes was greater ( p < 0.01) in Etoh vs. FD: fatty liver, 3.0 ± 1.2 vs. 1.2 ± 0.4; necrosis (foci/mm2), 3.9 ± 2.3 vs. 0.4 ± 0.3; inflammation (cells/mm2), 19.0 ± 6.3 vs. 1.8 ± 0.6. Centrilobular collagen deposition (% area), assessed by Sirius Red staining, was greater in Etoh vs. FD. Levels of endotoxin, ALT, CYP2E1 and lipid peroxidation markers were also higher ( p < 0.01) in Etoh vs. FD. Levels of NF-κB and mRNA of pro-inflammatory mediators (TNF-α, COX-2, iNOS) and procollagen-I were increased ( p < 0.05) in ethanol-fed rats. Immunohistochemical analysis showed more intense staining for both iNOS and nitrotyrosine in the centrilobular areas in the Etoh vs. FD groups. The greater area of positive staining for iNOS and nitrotyrosine in Etoh vs. FD was confirmed by Western Blot analysis. An increase in the expression of mRNA for profibrogenic genes ( p < 0.05) was seen in ethanol-fed rats. Conclusions: A voluntary feeding regimen consisting of fish oil and ethanol in female rats is technically less demanding yet produces pathological and biochemical changes similar to those observed with the IG model. Pathological changes include fatty liver, necrosis and inflammation. Increased NF-κB and mRNA and protein levels of the pro-inflammatory mediators TNF-α, COX-2 and iNOS, coincided with the presence of necroinflammatory changes. The voluntary feeding regimen is proposed as an alternative to the IG model in the study of alcoholic liver injury. [ABSTRACT FROM AUTHOR]

Background: Women exhibit greater liver damage than men after chronic alcohol consumption. Similar findings are reported in animal models. Here, we determined whether differential liver injury occurred in male and female rats after feeding these animals liquid diets containing either ethanol or isocaloric dextrose with fish oil as the sole source of lipid. Methods: Control and ethanol liquid diets containing fish oil were pair-fed to male and female rats for 8 weeks. Liver damage was evaluated by triglyceride accumulation, lipid peroxide formation, serum transaminases, histological evaluation, and the activities of selected lysosomal and hepatoprotective enzymes. Results: Fatty liver was detected after ethanol feeding in both genders, but in female rats, triglyceride levels were 60% higher, lipid peroxides were 2-fold higher, and inflammatory cells were more evident than in males. A 2-fold elevation of cathepsin B in hepatic cytosol fractions, indicating lysosomal leakage, was detected in ethanol-fed female rats but no such elevation was observed in males. The basal activity of the hepatoprotective enzyme, betaine-homocysteine methyltransferase was 4-fold higher in livers of control male rats than females, and the enzyme activity was further elevated in ethanol-fed male rats but not in females. Conclusions: Thus, female rats given ethanol in a diet containing fish oil exhibited more severe liver damage than males. We propose that this difference results, in part, from a greater tendency by females to accumulate hepatic fat, thereby enhancing the potential for oxidative stress, which in turn leads to hepatic inflammation. In addition, our findings indicate that female rats have a higher susceptibility to liver damage because of a reduced capacity for hepatoprotection. [ABSTRACT FROM AUTHOR]

Background: l-Buthionine ( S,R) sulfoximine (BSO) is an inhibitor of glutathione biosynthesis and has been used as an effective means of depleting glutathione from cells and tissues. Here we investigated whether treatment with BSO enhanced ethanol-induced liver injury in mice. Methods: Female C57Bl/6 mice were pair fed with control and ethanol-containing liquid diets in which ethanol was 29.2% of total calories. During the final 7 days of pair feeding, groups of control-fed and ethanol-fed mice were given 0, 5 or 7.6 mM BSO in the liquid diets. Results: Compared with controls, ethanol given alone decreased total liver glutathione. This effect was exacerbated in mice given ethanol with 7.6 mM BSO, causing a 72% decline in hepatic glutathione. While ethanol alone caused no decrease in mitochondrial glutathione, inclusion of 7.6 mM BSO caused a 2-fold decline compared with untreated controls.l-Buthionine ( S,R) sulfoximine did not affect ethanol consumption, but serum ethanol levels in BSO-treated mice were nearly 6-fold lower than in mice given ethanol alone. The latter decline in serum ethanol was associated with a significant elevation in the specific activities of cytochrome P450 2E1 and alcohol dehydrogenase in livers of BSO-treated animals. Ethanol consumption caused a 3.5-fold elevation in serum alanine aminotransferase levels but the enzyme fell to control levels when BSO was included in the diet.l-Buthionine ( S,R) sulfoximine administration also attenuated ethanol-induced steatosis, prevented the leakage of lysosomal cathepsins into the cytosol, and prevented the ethanol-elicited decline in proteasome activity. Conclusions: l-Buthionine ( S,R) sulfoximine, administered with ethanol, significantly depleted hepatic glutathione, compared with controls. However, despite the decrease in hepatic antioxidant levels, liver injury by ethanol was alleviated, due, in part, to a BSO-elicited acceleration of ethanol metabolism. [ABSTRACT FROM AUTHOR]

Zhang H-Y, Nanji AA, Luk JM, Huang X-R, Lo C-M, Chen YX, Yuen S-T, Lan HY, Lau GKK. Macrophage migration inhibitory factor expression correlates with inflammatory changes in human chronic hepatitis B infection.Liver International: 2005: 25: 571–579.© Blackwell Munksgaard 2005Macrophage migration inhibitory factor (MIF) has emerged to be a pivotal cytokine in immune-mediated diseases.To investigate the role of MIF in chronic hepatitis B infection, we studied two groups of hepatitis B surface antigen positive patients: group 1 (immune tolerant,n=16) and group 2 (immune clearance,n=16). Serum level of MIF was measured by enzyme-linked immunosorbent assay and intrahepatic expression of MIF, macrophage and T-cell localisation were detected by double immunohistochemistry.An increased serum MIF correlated significantly with increased serum alanine aminotransferase activity (r=0.73,P<0.001) and the severity of necroinflammatory injury (r=0.642,P<0.001). In group 2, there was marked MIF mRNA expression in all KP-1+ macrophages and CD45RO+ activated T cells and, to a lesser extent, in hepatocytes within inflammatory areas. In contrast to its mRNA expression, the cytoplasmic MIF protein level in hepatocytes, infiltrating macrophages and T cells within the inflammatory area was reduced, which probably contributed to the increased serum MIF level.Our data suggested that MIF played a role in sustaining cell-mediated hepatic injury during the immune-clearance phase of chronic hepatitis B infection. [ABSTRACT FROM AUTHOR]

The article summarizes the proceedings of a symposium on recent advances in research on the pathogenesis of alcoholic liver disease at the 2001 RSA meeting in Montreal, Canada. The chairs were Amin A. Nanji and Samuel W. French. The presentations were (1) Role of inflammatory mediators in alcoholic liver injury by Amin A. Nanji, (2) Role of endotoxin, lipopolysaccharide binding protein, CD14 and Toll receptors in alcoholic liver injury by Grace Su, (3) Fatty acid ethyl esters: toxicity, metabolism and markers of ethanol intake by Michael Laposata, and (4) Cyclic changes in gene expression when rats are fed alcohol at a constant rate by Samuel W. French. [ABSTRACT FROM AUTHOR]

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Carol A. Casey and Amin Nanji. The presentations were (1) Mechanisms of apoptosis in alcoholic liver disease, by Amin A. Nanji; (2) Impaired receptor-mediated endocytosis: Its role in alcoholic apoptosis, by Carol A. Casey; (3) Toxicity of ethanol in HepG2 cells that express CYP2E1, by Arthur I. Cederbaum; (4) Mitochondrial regulation of ethanol-induced hepatocyte apoptosis, by M. Adachi; and (5) Apoptosis in alcoholic hepatitis, by T. Takahashi. [ABSTRACT FROM AUTHOR]

Background: Fatty acid ethyl esters (FAEE) are nonoxidative ethanol metabolites that have been shown to be long term markers of ethanol intake and have been implicated as mediators of ethanol-induced cell injury. Previous studies have indicated that the fatty acid composition of the FAEE found in the plasma of human subjects after ethanol ingestion is predominantly ethyl palmitate and ethyl oleate. This raised the possibility that there is some selectivity toward the fatty acid used for FAEE to be exported from the liver into the blood. Methods: To address the hypothesis that the fatty acid composition of FAEE secreted from organs, such as the liver and pancreas, differs from the fatty acid composition of FAEE in the organs, this study was performed using rats that received ethanol by intra-arterial infusion. Results: It was found that the fatty acids in FAEE differed significantly in plasma versus liver, bile versus liver, and pancreatic secretions versus pancreas. Conclusions: These results indicate that organs selectively export certain FAEE species. [ABSTRACT FROM AUTHOR]

Background: The role of free radicals in alcoholic liver injury remains uncertain. These experiments were conducted to measure radical formation in rats that were fed alcohol along with either fish oil or saturated fats, which cause different types of liver pathology. Methods: Liquid diets containing alcohol or isocaloric dextrose were administered to rats by intragastric infusion for 2 weeks. Radical intermediates detected by spin trapping were measured in bile. Results: In rats that were fed alcohol plus fish oil, biliary concentrations of trapped radicals, which most likely originated from lipids, were 6-fold higher than in controls that were fed fish oil plus dextrose. High rates of radical formation persisted 24 hr after alcohol withdrawal, when all alcohol had been metabolized. In contrast, diets containing alcohol and medium chain triglycerides did not stimulate lipid radical formation. Conclusions: High rates of lipid radical formation were observed only in rats that were fed alcohol in combination with a fish oil diet, and a persistent flux of radical formation continued after alcohol with- drawal. These radical phenomena precede serious liver pathology, which develops after longer periods of fish oil plus alcohol diets. [ABSTRACT FROM AUTHOR]

The influence of dietary fat and alcohol on hepatic microsomal levels of cytochromes P-450 2E1, 2B, and 4A; phospholipases A and C; and UDP-glucuronosyltransferase was studied in the intragastric feeding rat model for alcoholic liver injury. Eight groups of animals were evaluated. Control and ethanol fed rats received either saturated fat or corn oil and were killed after 2 weeks and 1 month of feeding. All animals were pair-fed by continuous infusion of liquid diet through permanently implanted gastric cannulas. Alcoholic liver injury developed only in the corn oil-ethanol-fed groups and was manifest by 1 month. Livers were subjected to the following analyses: pathologic evaluation of liver injury; levels of cytochromes P-450 2E1, 2B, and 4A protein and mRNA; aniline hydroxylase activity; and phospholipase A and C and UDP-glucuronosyltransferase activities. Ethanol-induced increases in cytochromes P-450 2E1 and 2B protein determined by Western blotting were greatest in the corn oil-ethanol-fed group, which developed pathologic changes in the liver. Cytochromes P-450 2E1 and 2B1 mRNA levels were unaffected, suggesting that posttranscriptional mechanisms are responsible for the increase in the corresponding P-450 proteins. In contrast, cytochrome P-450 4A levels were higher in the saturated fat-ethanol groups compared with the corn oil-ethanol groups. Phospholipase A and phospholipase C levels were higher in the corn oil-ethanol groups compared with pair-fed dextrose controls and the saturated fat-ethanol groups. UDP-glucuronosyltransferase levels declined with time in the ethanol-fed groups. These observations are discussed in the context of a model whereby the induction of phospholipases A and C and cytochromes P-450 2E1 and 2B1 in corn oil-ethanol-fed rats provide arachidonic acid substrate and induce lipid peroxidation, respectively. These changes may account for the more severe pathologic changes that develop in corn oil-ethanol-fed animals compared with animals fed saturated fat and ethanol. [ABSTRACT FROM AUTHOR]

The rat intragastric feeding model for alcoholic liver disease was used to study the effect of different diets on the fatty acid composition of liver microsomes. Rats were fed corn oil and ethanol (CE), saturated fat and ethanol (SF+E) or corn oil and dextrose (CD) for either 2 or 4 weeks. Rats were also fed saturated and dextrose (SF+D) for 4 weeks. In comparison with the CD diet, lower levels of arachidonic acid were detected in rats fed the CE, SF+E, and SF+D diets. However, the diet-induced changes in levels of arachidonic acid varied as a function of length of feeding. In rats fed the CE diet, we detected a significant decrease in the level of arachidonic acid compared with CD animals. Conversely, in rats fed the SF+E diet, the level of arachidonic acid increased compared with the SF+D group. In addition, a significant correlation was noted between levels of oleic acid and arachidonic acid in both corn oil ( r=-0.85, p < 0.01) and saturated fat ( r=-0.76, p < 0.05) groups. However, the changes in levels of arachidonic acid and oleic acid were in opposite directions in the two groups. Levels of docosahexaenoic acid decreased between the 2 and 4 weeks in animals maintained on the CE diet. Levels of stearic acid increased between 2 and 4 weeks in rats fed the SF+E diet. The lowest level of linoleic acid was detected in the SF+D and SF+E groups, but levels of linoleic acid remained constant in all groups throughout the study. Histological evaluation indicated that ethanol-induced liver injury was limited to rats fed the diet containing corn oil for 4 weeks. Thus, diet-dependent differences in liver microsomal fatty acid composition may help to explain why ethanol-induced liver injury occurs in rats fed corn oil, but not saturated fat. [ABSTRACT FROM AUTHOR]

We evaluated the role of changes in microsomal phospholipases (A and C) and arachidonic acid in the intragastric rat feeding model. The experimental animals (male Wistar rats), divided into 4-5 rats/group, were fed the following diets: corn oil and ethanol and corn oil plus dextrose. One set of groups was killed after 2 weeks of feeding, and the second set was killed after 1 month. For each animal, microsomal analysis of cytochrome P-450 2E1 (CYP 2E1) and fatty acids was done. Fourteen animals had analyses of phospholipase C (PLC) and phospholipase A (PLA), and 10 animals had measurements of conjugated dienes. A significant correlation was obtained between the level of CYP 2E1 and the decrease in arachidonic acid (AA) from baseline levels ( r= 0.69, p < 0.01). The decrease in AA also correlated with the increase in conjugated dienes ( r= 0.70, p < 0.05). PLA and PLC activities were both significantly increased in the corn oil and ethanol groups. The activity of PLC correlated with the decline in AA ( r= 0.69, p < 0.01). The correlations noted between the decrease in microsomal AA and CYP 2E1 induction and conjugated diene formation suggest that these processes may be interlinked especially in regard to generation of lipid peroxides that may play a role in alcoholic liver injury. [ABSTRACT FROM AUTHOR]

The amount and type of dietary fat is thought to be important in the pathogenesis of alcoholic liver disease (ALD). We investigated the role of different dietary fats in our rat model for ALD. Liver pathology was evaluated in rats fed ethanol and lard or tallow or corn oil over a period of 2 to 6 months. All experimental animals were pair-fed the same diet as controls except that glucose was isocalorically replaced by ethanol. Rats fed tallow and ethanol developed none of the features of ALD, those fed lard and ethanol developed minimal to moderate disease, rats fed corn oil and ethanol developed the most severe pathology. The degree of histopathological abnormality correlated with the linoleic acid content of fat in the diet (tallow 0.7%, lard 2.5%, corn oil 56.6%). We postulate that linoleic acid facilitates development of ALD and provides an explanation for our previous epidemiological observations. [ABSTRACT FROM AUTHOR]

Arachidonic acid concentrations in liver are decreased in response to ethanol administration. In addition, the oxygenated products of arachidonic acid metabolites could affect the severity of alcoholic liver injury. Selective utilization of arachidonic acid by the cyto-chrome P-450 system could, in part, account for the decrease in arachidonic acid. To evaluate this pathway further, male Wistar rats were fed different dietary fats: medium chain triglycerides, palm oil, and corn oil or fish oil with either ethanol or isocaloric amounts of dextrose. Histopathology, cytochrome P-45ME1 (CYP2E1) and cy-tochrome P-4504A (CYP4A), and ω- and (ω-1)-hydroxylation products of lauric and arachidonic acids were evaluated. Ethanol induction of CYP2El was related to the concentration of polyunsaturated fatty acids in the diet; induction of CYP4A by ethanol was seen in all groups. The highest levels of 11-hydroxy-lauric acid and 19-hydroxyarachidonic acid (ω-1) were seen in rats fed ethanol with palm oil and corn oil. Highly significant correlations were seen between the (ω-1)-hydroxylation products and CYP2E1 activity. No correlation was seen between the ω-hydroxylation products and CYP2E1 activity. In contrast, the levels of ω-hydroxylation products correlated with CYP4A. The overall results showed a significant increase in (ω-1)-hydroxylation products in rats fed diets containing significant amounts of linoleic acid (i.e., palm oil and corn oil). [ABSTRACT FROM AUTHOR]

We used the intragastric feeding rat model to investigate the relationship between severity of alcoholic liver injury, apoptosis, bcl-2 protein expression, and lipid peroxidation. Rats were fed ethanol with different dietary fats (saturated fat, corn oil, and fish oil) for a 1-month period. Apoptosis was evaluated using an immunohistochemical method, and flow cytometry. Bcl-2 protein concentrations in liver were evaluated by Western blot analysis and lipid peroxidation by measurement of conjugated diems. Pathological changes (fatty liver, necrosis, and inflammation) were present in com oil-ethanol and fish oil-ethanol groups only. The highest number of apoptotic cells were seen in the group of rats exhibiting her Injury. The fish oil-ethanol-fed group had the highest concentrations of bcl-2 protein; this protein was localized in the bile duct epithelial and inflammatory cells. A significant correlation was seem between bcl-2 protein assessed densitometrically and the number of inflammatory cells/mm2 ( r= 0.78, p < 0.02) and conjugated diene levels ( r= 0.82, p < 0.01). Increased numbers of apoptotic cells were seen in rats developing ethanol-induced pathological liver injury. Increased bcl-2 protein concentrations are associated with the presence of inflammatory cells and lipid peroxidation. [ABSTRACT FROM AUTHOR]

We studied the effects of long-term ethanol ingestion and dietary fat on Ito cell activation morphometrically in rats. Sixteen pairs of Wistar male rats were divided into two groups, one fed tallow and the other fed corn oil as the source of dietary fat. Each group of rats were pair-fed a nutritional adequate liquid diet containing either corn oil (CF) or tallow (TF) as fat as well as protein and carbohydrate. Half of each group received ethanol, the rest were pair-fed isocaloric amounts of dextrore via an implanted gastric tube for up to 5 months. Morphometric analysis of the change in fat and rough endoplasmic reticulum (RER) of Ito cells was performed on electron micrographs obtained from monthly biopsies including baseline. Ito cell activation was assessed by a decrease in the ratio of fat/RER in Ito cells. The ratio of fat/RER in Ito cells of alcoholic rats fed the CF diet (CFA) gradually decreased. The ratio war found to be lower than in the pair-fed control rats (CFC) at 5 months of feeding. CFA 1.74 ± 0.57, vs. 7.46 ± 2.05, respectlvely, p < 0.05, mean ± se). Ito cell fat also significantly decreased at 5 months of feeding (p < 0.05). The fat/ RER ratio In CFA significantly decreased only subsequent to the development of fatty change, necrosis, and inflammation followed by fibrosis of the liver. In contrast, the TFA rats did not show a significant decrease in the fat/RER ratio in the Ito cells throughout the study, while TFC rats showed an increase in the fat/RER ratio. Minimal pathological changes were observed In the livers of CFC, TFA, and TFC rats. These results indicate that activation of Ito cells at a signifiant level occurred only late in the course of feeding alcohol after moderate to severe abnormalities in liver hlstology had developed, although activation may have begun at an earlier time of ethanol feeding. The results Indicate that dietary fatty acid composition may be an important factor in the pathogenesis of ethanol-induced Ito cII activation. [ABSTRACT FROM AUTHOR]

Mortality from cirrhosis in many countries deviates markedly from that expected for a given per capita alcohol intake. We investigated the possibility that dietary factors might explain the deviation expected and actual mortality rates in different countries. Deviations from expected cirrhosis mortality was calculated as a percentage for 17 different countries, all of whom had carrier rates for hepatitis B virus of less than 2%. The percentage of deviation was correlated with dietary intake of sautrated fat, polyunsaturated fat, cholesterol, and also with mortality from ischemic heart disease. The percentage of deviation correlated inversely with dietary cholesterol ( r= -0.86, p 0.001) and saturated fat ( r= -0.80, p 0.001) and positively with polyunsaturated fats ( r= -0.55 p 0.05). This suggests that both saturated fat and cholesterol protect against alcoholic cirrhosis while polyunsaturated fats promote cirrhosis. The correlation between percentage of deviation and ischemic heart disease ( r= -0.78, p 0.002) suggests that those factors that promote ischemic heart diease protect against alcoholic cirrhosis. [ABSTRACT FROM AUTHOR]

Background: Because of its role in degrading the bulk of intracellular proteins and eliminating damaged proteins, the proteasome is important in maintaining cell viability. Previously, we showed a 35-40% decrease in proteasome peptidase activity when ethanol was administered to rats by intragastric infusion. We hypothesized that this reduction was caused by ethanol-elicited oxidative stress, the degree of which varies depending on the method of ethanol administration. This study examined the relationship of proteasome activity and content with ethanol-induced oxidative stress and the degree of liver injury., Methods: Rats were given ethanol or isocaloric dextrose-containing liquid diets by intragastric infusion for 1 month. The diets contained medium-chain triglycerides (MCT), palm oil (PO), corn oil (CO), or fish oil (FO) as the principal source of fat., Results: Rats given ethanol and MCT exhibited no significant liver pathology, whereas cumulative pathology scores in ethanol-fed rats given PO, CO, or FO were 2.5, 5.4 and 7.0, respectively, indicating that ethanol and FO caused the greatest liver damage. The severity of liver pathology in the last three groups of animals correlated with levels of lipid peroxides and serum 8-isoprostanes. Alpha smooth muscle actin, an indicator of stellate cell activation, was increased relative to controls in the livers of all ethanol-fed rats except FO-fed animals, in which both control and ethanol-fed rats had similar levels of this protein. In livers of CO and FO ethanol-fed rats, proteasome chymotrypsin-like activity was decreased by 55-60%, but there was no quantitative alteration in 20S proteasome subunit content. In contrast, ethanol affected neither proteasome activity nor its content in MCT- and PO-treated animals., Conclusions: Our findings indicate that the severity of liver injury and ethanol-induced oxidative stress is associated with a reduction in proteasome catalysis., (Copyright 2004 Research Society on Alcoholism)

Background: Cytochrome P-450 3A (CYP3A) is responsible for the metabolism of numerous therapeutic agents. The content of CYP3A seems to be affected by ethanol ingestion. Because ethanol is used widely, its potential interaction with CYP3A is of great interest. The effects of ethanol on CYP3A content and activity were assessed in different in vivo and in vitro models., Methods: Rats fed either the Lieber-DeCarli ethanol-containing diet or an ethanol and liquid diet via the intragastric tube feeding method were used. Additionally, HepG2 cell lines that constitutively and stably express human CYP3A4 were constructed to study ethanol interactions with CYP3A4., Results: In all models tested, ethanol induced CYP3A activity and content, as assessed by the metabolism of fentanyl, a sensitive and specific CYP3A substrate, and Western blot analysis, respectively. In the CYP3A4-expressing HepG2 cell line, incubation with ethanol caused a dose-dependent increase in CYP3A4 activity. Ethanol also increased messenger RNA levels of CYP3A4. In the HepG2-CYP3A4 line, incubation with cycloheximide caused a decrease in fentanyl metabolism secondary to a decrease in CYP3A4 levels; this decrease was prevented by coincubation of cycloheximide with ethanol., Conclusions: Ethanol induced CYP3A activity and content both in vitro and in vivo. There may be multiple mechanisms of induction of CYP3A4 by ethanol, including stabilization of messenger RNA and protein. Ethanol-induced increases in both the protein level and activity of CYP3A4 may play a role that might be of pathophysiological or clinical significance.