Alcohol-fed Rats Research Articles

Proteome Analysis of the Cerebellum Tissue in Chronically Alcohol-Fed Rats

Background: Cerebellar degeneration is one of the most common effects of chronic alcohol exposure, and Purkinje cells are the main targets of alcohol-induced cerebellum neuropathology, but the underlying mechanism remains unclear. Methods: Eight rats were fed for 8 weeks with a nutritionally adequate liquid diet containing either ethanol as 36% of the total caloric content or an isocaloric control diet. Rat cerebellum homogenates were subjected to agarose two-dimensional electrophoresis (2-DE), and the protein expression profiles in chronically alcohol-fed rats and the pair-fed controls were compared. The observed changes in the protein expression levels were confirmed using immunoblotting analysis. Results: Three protein spots changed significantly in intensity according to 2-DE. Based on immunoblotting analysis, low expression levels of microtubule-associated protein-2 (MAP2) and the overexpression of voltagedependent anion channel protein 1 (VDAC1) were observed in the cerebellum of alcohol-fed rats. The expression levels of both proteins did not change in other parts of the brain. Conclusions: Low expression levels of MAP2 and overexpression of VDAC1 were detected using proteome analysis of the cerebellum tissue from chronically alcohol-fed rats. Changes in the expression of these proteins may be related to cerebellar degeneration following chronic alcohol consumption.

Alcohol Differentially Alters Extracellular Matrix and Adhesion Molecule Expression in Skeletal Muscle and Heart

The production of fibrosis in response to chronic alcohol abuse is well recognized in liver but has not been fully characterized in striated muscle and may contribute to functional impairment. Therefore, the purpose of this study was to use an unbiased discovery-based approach to determine the effect of chronic alcohol consumption on the expression profile of genes important for cell-cell and cell-extracellular matrix (ECM) interactions in both skeletal and cardiac muscle. Adult male rats were pair-fed an alcohol-containing liquid diet or control diet for 24weeks, and skeletal muscle (gastrocnemius) and heart were collected in the freely fed state. A pathway-focused gene expression polymerase chain reaction array was performed on these tissues to assess mRNA content for 84 ECM proteins, and selected proteins were confirmed by Western blot analysis. In gastrocnemius, alcohol feeding up-regulated the expression of 11 genes and down-regulated the expression of 1 gene. Alcohol increased fibrosis as indicated by increased mRNA and/or protein for collagens α1(I), α2(I), α1(III), and α2(IV) as well as hydroxyproline. Alcohol also increased α-smooth muscle actin protein, an index of myofibroblast activation, but no concomitant change in transforming growth factor-β was detected. The mRNA and protein content for other ECM components, such as integrin-α5, L-selectin, PECAM, SPARC, and ADAMTS2, were also increased by alcohol. Only laminin-α3 mRNA was decreased in gastrocnemius from alcohol-fed rats, while 66 ECM- or cell adhesion-related mRNAs were unchanged by alcohol. For heart, expression of 16 genes was up-regulated, expression of 3 genes was down-regulated, and 65 mRNAs were unchanged by alcohol; there were no common alcohol-induced gene expression changes between heart and skeletal muscle. Finally, alcohol increased tumor necrosis factor-α and interleukin (IL)-12 mRNA in both skeletal and cardiac muscle, but IL-6 mRNA was increased and IL-10 mRNA decreased only in skeletal muscle. These data demonstrate a fibrotic response in striated muscle from chronic alcohol-fed rats which is tissue specific in nature, suggesting different regulatory mechanisms.

Coordinated regulation of scopoletin at adipose tissue–liver axis improved alcohol-induced lipid dysmetabolism and inflammation in rats

There is increasing evidence that alcohol-induced white adipose tissue (WAT) dysfunction contributes to disturbance of hepatic lipid metabolism. This study investigated the effects of scopoletin on lipid homeostasis and inflammation at the WAT and liver in chronic alcohol-fed rats. Rats were fed a liquid diet containing 5% alcohol with or without two doses of scopoletin (0.001% and 0.005%) for 8 weeks. Scopoletin decreased serum triglyceride and cytokines (TNFα and IL-6) levels and hepatic and WAT lipid levels, whereas it increased WAT adiponectin mRNA and serum adiponectin levels, up-regulated hepatic gene and protein expression of AdipoR2 and activated AMPK. Additionally, scopoletin inhibited the expression of lipogenic genes (SREBP-1c and Fasn) and increased the expression of fatty acid oxidative genes (PPARα, Acsl1, CPT, Acox, and Acaa1a) in both WAT and liver. Alcohol led to significant up-regulation of WAT lipolysis and hepatic Cidea gene expression, whereas it decreased the WAT Cidea gene level; however, scopoletin reversed these changes. Scopoletin significantly down-regulated TLR4 signaling genes such as MyD88, TRIF, NFκB, TNFα and IL-6 in WAT and liver. These results indicated that coordinated regulation of scopoletin at the WAT–liver axis may play an important role in improvement of alcohol-induced lipid dysregulation and inflammation.

Dietary saturated fatty acids reduce hepatic lipid accumulation but induce fibrotic change in alcohol-fed rats.

In this study, we evaluated the influence of an ethanol-containing diet with high saturated fatty acids (SFAs) on alcoholic liver disease (ALD) in rats. Male Wistar rats weighing about 160 g were divided into four groups: an ethanol (E) group fed an ethanol-containing liquid diet with 36% total calories as fat (corn oil, olive oil and safflower oil); a control (C) group pair-fed an isoenergetic diet without ethanol; an ethanol with saturated fat (EHS) group fed an ethanol-containing diet which contained 40% total calories as fat (90% lard); and a control with saturated fat (CHS) group fed an isoenergetic diet without ethanol, which contained 40% total calories as fat. After 8 weeks of treatment, the liver weight and plasma aspartate aminotransferase (AST) activities in E and EHS groups were significantly higher than those of C group. Significantly higher scores of inflammation, necrosis, and fatty changes were found in E group, whereas significantly higher scores of necrosis, bile duct hyperplasia, and fibrosis were found in EHS group. Although significantly lower plasma adiponectin concentrations were observed in both E and EHS groups, compared to C group, plasma adiponectin in EHS group was significantly higher than that in E group. There was no change in hepatic peroxisome proliferator activated receptor (PPAR)-α expression between E and C groups, and rats in EHS group showed a significantly elevated level compared to the other groups. A lower hepatic sirtuins (SIRT)-1 level was found in E group, but it did not reach statistical significance. Moreover, the highest plasma TGF-β1 level was found in EHS group. Compared to C group, the hepatic reduced glutathione/oxidized glutathione ratio and thiobarbituric acid (TBA)-reactive substance level were significantly increased in E and EHS groups; however, there was no significant difference between E and EHS groups. Significantly increased hepatic CYP2E1 expression was observed in both E and EHS groups, while at the same time, hepatic CYP2E1 in EHS group was the highest among all groups. The hepatic tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-10 concentrations in the E group were significantly higher than those in C group, whereas the hepatic IL-6 and IL-10 concentrations in ES group were significantly lower than those of E group. These results suggested that dietary saturated fats may inhibit hepatic fat accumulation and induce hepatic fibrosis in rats under chronic alcohol intake.

Alveolar Barrier Function in Alcoholic Lung Syndrome Is Impaired by Tight Junction Destabilization

Alcohol abuse increases the severity of acute respiratory distress syndrome by impairing alveolar barrier function and increasing airspace flooding. We used a rodent model of chronic alcohol ingestion and cultured primary alveolar epithelial cells (AECs) to investigate the influence of alcohol on tight junction formation and function. AECs from alcohol-fed rats had disrupted tight junction morphology and were leakier than control AECs. Alcohol-induced changes to AEC tight junctions were accompanied by increased expression of a claudin family tight junction protein, claudin-5. Claudin-18 also increased in response to alcohol; however, claudin-4 was decreased. Using an adenovector to increase claudin-5 expression by normal AECs mimicked the effects of alcohol on tight junctions, whereas short hairpin interfering RNA targeting to decrease claudin-5 improved tight junction morphology and function of AECs from alcohol-fed rats. We then used stochastic optical reconstruction microscopy to examine interactions in situ between claudin-5, claudin-18, and the tight junction scaffold protein, zonula occludens-1 at a level of 20-nm resolution. Stochastic optical reconstruction microscopy analysis of AECs revealed that alcohol significantly increased colocalization between claudin-5 and claudin-18, and that this was associated with a significant decrease in colocalization between claudin-18 and zonula occludens-1. Thus, increased claudin-5 destabilized integration of claudin-18 into tight junctions. Taken together, these data suggest that increased claudin-5 disrupts alveolar barrier function, and that strategies to target claudin-5 may provide a therapeutic approach to improve barrier function in acute respiratory distress syndrome and the alcoholic lung syndrome.

Scopoletin 보충이 만성 알코올을 급여한 흰쥐의 인슐린저항성 및 항산화방어계에 미치는 영향

This study investigated the effects of scopoletin (6-methoxy-7-hydroxycoumarin) supplementation on insulin resistance and the antioxidant defense system in chronic alcohol-fed rats. Rats were fed a Lieber-Decarli liquid diet containing 5% ethanol with or without two doses of scopoletin (0.01 and 0.05 g/L) for 8 weeks. Pair-fed rats received an isocaloric carbohydrate liquid diet. Chronic alcohol did not affect fasting serum glucose levels, although it induced glucose intolerance and hyperinsulinemia compared with the pair-fed group and led to insulin resistance. Both doses of scopoletin similarly improved glucose intolerance, serum insulin level, and insulin resistance. Scopoletin supplementation significantly activated phosphatidyl inositol 3-kinase, which was inhibited by chronic alcohol. Two doses of scopoletin up-regulated hepatic mRNA expression and activity of glucokinase as well as down-regulated mRNA expression and activity of glucose-6-phosphatase compared with the alcohol control group. Both doses of scopo- letin significantly reduced cytochrome P450 2E1 activity and elevated aldehyde dehydrogenase 2 activity, resulting in a lower serum acetaldehyde level compared with the alcohol control group. Chronic alcohol suppressed hepatic mRNA expression and activities of antioxidant enzymes such as superoxide dismutase, catalase, and glutathione perox- idase; however, they were reversed by scopoletin supplementation, which reduced hydrogen peroxide and lipid peroxide levels in the liver. These results indicate that dietary scopoletin attenuated chronic alcohol-induced insulin resistance and activated the antioxidant defense system through regulation of hepatic gene expression in glucose and antioxidant metabolism.

Dietary tomato powder inhibits alcohol-induced hepatic injury by suppressing cytochrome p450 2E1 induction in rodent models

Chronic and excessive alcohol consumption leads to the development of alcoholic liver disease (ALD) and greatly increases the risk of liver cancer. Induction of the cytochrome p450 2E1 (CYP2E1) enzyme by chronic and excessive alcohol intake is known to play a role in the pathogenesis of ALD. High intake of tomatoes, rich in the carotenoid lycopene, is associated with a decreased risk of chronic disease. We investigated the effects of whole tomato (tomato powder, TP), partial tomato (tomato extract, TE), and purified lycopene (LYC) against ALD development in rats. Of the three supplements, only TP reduced the severity of alcohol-induced steatosis, hepatic inflammatory foci, and CYP2E1 protein levels. TE had no effect on these outcomes and LYC greatly increased inflammatory foci in alcohol-fed rats. To further support the protective effect of TP against ALD, TP was supplemented in a carcinogen (diethylnitrosamine, DEN)-initiated alcohol-promoted mouse model. In addition to reduced steatosis and inflammatory foci, TP abolished the presence of preneoplastic foci of altered hepatocytes in DEN-injected mice fed alcohol. These reductions were associated with decreased hepatic CYP2E1 protein levels, restored levels of peroxisome proliferator-activated receptor-α and downstream gene expression, decreased inflammatory gene expression, and reduced endoplasmic reticulum stress markers. These data provide strong evidence for TP as an effective whole food prevention strategy against ALD.

Anti-inflammatory and antioxidant effects of umbelliferone in chronic alcohol-fed rats.

BACKGROUND/OBJECTIVESInflammation is associated with various types of acute and chronic alcohol liver diseases. In this study, we examined whether umbelliferone (7-hydroxycoumarin, UF) ameliorates chronic alcohol-induced liver damage by modulating inflammatory response and the antioxidant system.METHODSRats were fed a Liber-Decarli liquid diet containing 5% alcohol with or without UF (0.05 g/L) for 8 weeks, while normal rats received an isocaloric carbohydrate liquid diet.RESULTSChronic alcohol intake significantly increased serum tumor necrosis factor-α (TNF-α) and interleukin 6 levels and decreased interleukin 10 level; however, UF supplementation reversed the cytokines related to liver damage. UF significantly suppressed hepatic lipopolysaccharide binding protein, toll-like receptor 4 (TLR4), nuclear factor kappa B, and TNF-α gene expression increases in response to chronic alcohol intake. Masson's trichrome staining revealed that UF improved mild hepatic fibrosis caused by alcohol, and UF also significantly increased the mRNA expressions and activities of superoxide dismutase and catalase in liver, and thus, decreased lipid peroxide and mitochondrial hydrogen peroxide levels.CONCLUSIONSThe findings of this study indicate that UF protects against alcohol-induced liver damage by inhibiting the TLR4 signaling pathway and activating the antioxidant system.

The Role of LPS-TLR4 Pathway on Hepatic Fibrogenesis in Chronic Ethanol-Fed Rats

Introduction: Gut-derived lipopolysaccharide (LPS) has been proposed as a key player in the pathogenesis of alcoholic liver disease (ALD). The aims of this study were to investigate the role of LPS on hepatic fibrogenesis in a rat model of chronic alcohol feeding. Methods: Forty-eight Sprague-Dawley male rats were randomly divided as 4 groups and fed isocaloric Liber-DeCarli liquid diets ± alcohol (36% of total caloric value) for 8 weeks or 10 weeks. Plasma concentrations of LPS in portal veins from these rats were determined by spectrophotometric method. Rat liver tissue samples were examined for TLR4 and TGF-β1 mRNA by in situ hybridization. Immunohistochemistry was used to determine FSP-1 and vimentin for identification of activated HSC while F4/80 for recognition of Kuffer cells in serial sections of liver tissues. Computer image analysis was performed to measure the integrated optimal density (IOD) of FSP-1-positive HSC and TLR4 mRNA-positive cells. Hepatic collagen-I and α-SMA protein were analyzed by Western blot while IL-1, IL-6, TNF-α, and TGFβ1 mRNA were accessed by RT-PCR. Histological characteristics were evaluated by H and E staining and Masson’s Trichrome stain. Results: Masson’s Trichrome stain showed that there was a perisinusoidal fibrosis in rats fed ethanol at the end of 10 weeks, which was consistent with increased expression of collagen I by Western blot. Immunohistochemical stain showed there were abundant activated HSCs and some Kuffer cells in livers of rats fed ethanol at the end of 10 weeks, but a few HSC were seen in control-diet fed rats. Plasma LPS levels in portal veins were significantly higher in 10-week alcohol-fed rats than in 10-week controldiet-fed rats, but LPS levels were not increased in 8-week alcohol-fed rats. In situ hybridization analysis showed that a significant increase of TLR4 mRNA could be detected in abundant hepatocytes and some activated HSC and Kuffer cells in 10-week alcohol-fed rat livers, but in fewer endothelial cells of central vein in control-diet-fed rats. Bivariate correlation analysis showed that there was a positive correlation between the expression intensity of TLR4 mRNA in livers and the levels of plasma LPS in the portal vein of 10-week alcohol-fed rats (r=0.856; p<0.05); furthermore, the expressions of proinflammatory cytokine mRNA, including IL-1, IL-6, and TNF-α, as well as profibrogenic factor TGF-β1 mRNA, were increased in livers of 10-week alcohol-fed rats compared with control diet-fed rats. Conclusion: This study highlights the role of gut-derived LPS on hepatic fibrogenesis in a rat model of chronic alcohol feeding.

Effects of triterpenoid from Schisandra chinensis on oxidative stress in alcohol-induced liver injury in rats.

Alcohol-induced oxidative stress plays a crucial role in the pathological development of alcoholic liver disease. The aim of this study was to investigate the effects of triterpenoid from Schisandra chinensis on oxidative stress in alcohol-induced liver injury in rats. We found that the administration of triterpenoid attenuated alcohol-induced oxidative stress in multiple organs including liver. Moreover, the impaired liver function and histological changes resulted from alcohol consumption was improved by triterpenoid treatment. Finally, we found that pretreatment with triterpenoid from Schisandra chinensis to alcohol-fed rats increased the expression level of haem oxygenase-1 (HO-1) while inhibited the induction of cytochrome P-450 2E1 (CYP2E1) in liver microsomes. Further assays revealed that the microsomal activity of HO-1 was accordingly induced whereas CYP2E1 was suppressed in rats received triterpenoid intervention. Our findings suggest that triterpenoid from Schisandra chinensis may protect against alcohol-induced liver injury through ameliorating oxidative stress in rats.

Dietary umbelliferone attenuates alcohol-induced fatty liver via regulation of PPARα and SREBP-1c in rats

This study investigated the effects of umbelliferone (UF) on alcoholic fatty liver and its underlying mechanism. Rats were fed a Lieber–DeCarli liquid diet with 36% of calories as alcohol with or without UF (0.05 g/L) for 8 weeks. Pair-fed rats received an isocaloric carbohydrate liquid diet. UF significantly reduced the severity of alcohol-induced body weight loss, hepatic lipid accumulation and droplet formation, and dyslipidemia. UF decreased plasma AST, ALT, and γGTP activity. UF significantly reduced hepatic cytochrome P450 2E1 activities and increased alcohol dehydrogenase and aldehyde dehydrogenase 2 activities compared to the alcohol control group, which resulted in a lower plasma acetaldehyde level in the rats that received UF. Chronic alcohol exposure inhibited hepatic AMPK activation compared to the pair-fed rats, which was reversed by UF supplementation. UF also significantly suppressed the lipogenic gene expression (SREBP-1c, SREBP-2, FAS, CIDEA, and PPARγ) and elevated the fatty acid oxidation gene expression (PPARα, Acsl1, CPT, Acox, and Acaa1a) compared to the alcohol control group, which could lead to inhibition of FAS activity and stimulation of CPT and fatty acid β-oxidation activities in the liver of chronic alcohol-fed rats. These results indicated that UF attenuated alcoholic steatosis through down-regulation of SREBP-1c-mediated lipogenesis and up-regulation of PPARα-mediated fatty acid oxidation. Therefore, UF may provide a promising natural therapeutic strategy against alcoholic fatty liver.

유산균 발효 와송이 알코올성 유발 지방간 흰쥐의 조직 과산화지질 및 혈중 지질농도에 미치는 영향

The purpose of this study was to identify the effect on plasma levels of lipid and lipid peroxidation by administration of lactic acid bacteria (Lactobacillus bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus) fermented Orostachys malacophyllus (FOM) in alcohol fed rats. Male Sprague-dawley rats were randomly divided into seven groups: normal diet group (N), alcohol treated group (C), 2.5% (w/w) or 5% (w/w) OM treated group (2.5OM, 5OM), 2.5% (w/w) or 5% (w/w) fermented OM treated group (2.5FOM, 5FOM) and silymarin treated group (SM) as a positive control. As a result of measuring serum total lipid, C group were increased total lipid, free fatty acid content and were decreased HDL-cholesterol content, but 5FOM group were significantly decreased lipid content and were increased HDL-cholesterol content and accordingly reduced the incidence of atherosclerosis. Serum total protein content was similarly measured in all groups and serum albumin content was decreased in alcohol feeding groups compared to the N group. The 5FOM group had significantly decreased liver and serum triglycerides compared to the C group. The TBARS content in the liver, serum, testis, kidney, spleen, and heart were slightly decreased in the 5FOM group compared to the C group and the 5FOM group had an increased glutathione concentration. The 5FOM treatment was showed analogous results to those of the SM treatment, suggesting that FOM is can improve the lipid profiles of alcohol-fed rats.

Glycine Stabilize the Tissue Fatty Acid Composition in an Experimental Model of Alcohol-Induced Hepatotoxicity

Background and Aim: The aim of the present study was to investigate the effect of the administration of glycine, a non-essential amino acid on tissue fatty acid composition in experimental rats.Methods: Liver cell damage was induced by the administration of ethanol (7.9 g/kg b.w.) for 30 days by intragastric intubation. Control rats were given isocaloric glucose solution. Glycine was subsequently administered at a dose of 0.6 g/kg bodyweight every day by intragastric intubation for the next 30 days.Results: Feeding alcohol significantly elevated the activities of serum aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatases (ALP) and gamma-glutamyl transpeptidase (GGT) and altered the liver and brain fatty acid composition compared with control rats. Subsequently, glycine supplementation to alcohol-fed rats significantly lowered the activities of serum AST, ALT, ALP, GGT and normalized the liver fatty acid composition compared with untreated alcohol-fed rats.Conclusion: The present study demonstrates that oral administration of glycine confers a significant protective effect against alcohol-induced hepatotoxicity by virtue of its ability to optimize the activities of serum AST, ALT, ALP and GGT, as well as the tissue fatty acid composition. Background and Aim: The aim of the present study was to investigate the effect of the administration of glycine, a non-essential amino acid on tissue fatty acid composition in experimental rats. Methods: Liver cell damage was induced by the administration of ethanol (7.9 g/kg b.w.) for 30 days by intragastric intubation. Control rats were given isocaloric glucose solution. Glycine was subsequently administered at a dose of 0.6 g/kg bodyweight every day by intragastric intubation for the next 30 days. Results: Feeding alcohol significantly elevated the activities of serum aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatases (ALP) and gamma-glutamyl transpeptidase (GGT) and altered the liver and brain fatty acid composition compared with control rats. Subsequently, glycine supplementation to alcohol-fed rats significantly lowered the activities of serum AST, ALT, ALP, GGT and normalized the liver fatty acid composition compared with untreated alcohol-fed rats. Conclusion: The present study demonstrates that oral administration of glycine confers a significant protective effect against alcohol-induced hepatotoxicity by virtue of its ability to optimize the activities of serum AST, ALT, ALP and GGT, as well as the tissue fatty acid composition.

A Mechanism for Inhaled Anesthetic-Induced Solid Organ Injury: Inflammation

Background: Inhaled anesthetics, including halothane, iso- and sevoflurane induce proinflammatory cytokine release. Halothane is an inhaled anesthetic agent that is metabolized by the liver into a highly reactive product, trifluoroacetyl chloride, which can react endogenously to form a trifluoroacetyl-adduct (TFA-adduct). The MAA-adduct is formed by acetaldehyde and malondialdehyde reacting with endogenous proteins and is found in both patients and animals post-consumption of alcohol. These TFA and MAA-adducts have been shown to cause the release of proinflammatory cytokines by endogenous inflammatory cells. If both adducts share a similar mechanism of cell activation, receiving general anesthesia following alcohol ingestion could exacerbate the inflammatory response caused by the inhaled general anesthetic halothane and lead to solid organ (including liver and brain) injury. Methods: Control diet and alcohol-fed rats were randomized to receive halothane pretreatments by intraperitoneal injection mixed in sesame oil. Following the intraperitoneal injections, the intact heart was removed, HECs were isolated and stimulated with unmodified bovine serum albumin (Alb), MAA-modified Alb (MAA-Alb), Hexyl-MAA, or lipopolysaccharide (LPS), and supernatant concentrations of TNF-α were determined. Results: Halothane pre-treated rat HECs demonstrated significantly greater TNF-α concentration following MAA-adduct and LPS stimulation than the non-halothane pre-treated in both pair and alcohol-fed rats, but was significantly greater in the alcohol-fed groups. Conclusion: These results demonstrate that halothane and MAA-adduct pre-treatment will increase the inflammatory response (TNF-α release) in rat HECs following LPS and MAA stimulation in vitro. Also, these results suggest that halothane exposure may increase the risk of alcohol-induced solid organ injury secondary to TNF-induced inflammation. Other investigators have reported similar proinflammatory cytokine release with other (isoflurane and sevoflurane) inhaled anesthetic exposure, suggesting inhaled anesthetics should be used with caution in alcohol consuming humans.

A Mechanism for Inhaled Anesthetic-Induced Solid Organ Injury: Inflammation

Background: Inhaled anesthetics, including halothane, iso- and sevoflurane induce proinflammatory cytokine release. Halothane is an inhaled anesthetic agent that is metabolized by the liver into a highly reactive product, trifluoroacetyl chloride, which can react endogenously to form a trifluoroacetyl-adduct (TFA-adduct). The MAA-adduct is formed by acetaldehyde and malondialdehyde reacting with endogenousproteins and is found in both patients and animals post-consumption of alcohol. These TFA and MAA-adducts have been shown to cause the release of proinflammatorycytokines by endogenous inflammatory cells. If both adducts share a similar mechanism of cell activation, receiving general anesthesia following alcohol ingestion could exacerbate the inflammatory response caused by the inhaled general anesthetic halothane and lead to solid organ (including liver and brain) injury. Methods: Control diet and alcohol-fed rats were randomized to receive halothane pretreatments by intraperitoneal injection mixed in sesame oil. Following the intraperitoneal injections, the intact heart was removed, HECs were isolated and stimulated with unmodified bovine serum albumin (Alb), MAA-modified Alb (MAA-Alb), Hexyl-MAA, or lipopolysaccharide (LPS), and supernatant concentrations of TNF-α were determined. Results: Halothane pre-treated rat HECs demonstrated significantly greater TNF-α concentration following MAA-adduct and LPS stimulation than the non-halothane pre-treated in both pair and alcohol-fed rats, but was significantly greater in the alcohol-fed groups. Conclusion: These results demonstrate that halothane and MAA-adduct pre-treatment will increase the inflammatory response (TNF-α release) in rat HECs following LPS and MAA stimulation in vitro. Also, these results suggest that halothane exposure may increase the risk of alcohol-induced solid organ injury secondary to TNF-induced inflammation. Other investigators have reported similar proinflammatory cytokine release with other (isoflurane and sevoflurane) inhaled anesthetic exposure, suggesting that inhaled anesthetics should be used with caution in alcohol consuming humans.

Alcohol Consumption Decreases Rat Hepatic Creatine Biosynthesis Via Altered Guanidinoacetate Methyltransferase Activity

We have previously shown that decreased S-adenosylmethionine (SAM):S-adenosylhomocysteine (SAH) ratio generated in livers of alcohol-fed rats can impair the activities of many SAM-dependent methyltransferases. One such methyltransferase is guanidinoacetate methyltransferase (GAMT) that catalyzes the last step of creatine synthesis. As GAMT is the major utilizer of SAM, the purpose of the study was to examine the effects of ethanol (EtOH) on liver creatine levels and GAMT activity. Male Wistar rats were pair-fed the Lieber-DeCarli control and EtOH diet for 4 to 5weeks. At the end of the feeding regimen, the liver, kidney, and blood were removed from these rats for subsequent biochemical analyses. We observed ~60% decrease in creatine levels in the livers from EtOH-fed rats as compared to controls. The reduction in creatine levels correlated with lower SAM:SAH ratio observed in the livers of the EtOH-fed rats. Further, in vitro experiments with cell-free system and hepatic cells revealed it is indeed elevated SAH and lower SAM:SAH ratio that directly impairs GAMT activity and significantly reduces creatine synthesis. EtOH intake also slightly decreases the hepatocellular uptake of the creatine precursor, guanidinoacetate (GAA), and the GAMT enzyme expression that could additionally contribute to reduced liver creatine synthesis. The consequences of impaired hepatic creatine synthesis by chronic EtOH consumption include (i) increased toxicity due to GAA accumulation in the liver; (ii) reduced protection due to lower creatine levels in the liver, and (iii) reduced circulating and cardiac creatine levels. Chronic EtOH consumption affects the hepatic creatine biosynthetic pathway leading to detrimental consequences not only in the liver but could also affect distal organs such as the heart that depend on a steady supply of creatine from the liver.

Chronic alcohol consumption disrupts myocardial protein balance and function in aged, but not adult, female F344 rats

The purpose of this study was to assess whether the deleterious effect of chronic alcohol consumption differs in adult and aged female rats. To address this aim, adult (4 mo) and aged (18 mo) F344 rats were fed a nutritionally complete liquid diet containing alcohol (36% total calories) or an isocaloric isonitrogenous control diet for 20 wk. Cardiac structure and function, assessed by echocardiography, as well as myocardial protein synthesis and proteolysis did not differ in either alcohol- versus control-fed adult rats or in adult versus aged control-fed rats. In contrast, cardiac function was impaired in alcohol-fed aged rats compared with age-matched control rats. Additionally, alcohol feeding decreased cardiac protein synthesis that was associated with decreased phosphorylation of 4E-BP1 and S6K1. This reduction in mammalian target of rapamycin (mTOR) kinase activity was associated with reduced eIF3f and binding of both Raptor and eIF4G to eIF3. Proteasome activity was increased in alcohol-fed aged rats with a coordinate elevation in the E3 ligases atrogin-1 and muscle RING-finger protein-1 (MuRF1). These changes were associated with increased regulated in development and DNA damage response 1 (REDD1) and phosphorylation of AMP-activated protein kinase (AMPK) but no increase in AKT or forkhead transcription factor (FOXO)3 phosphorylation. Finally, markers of autophagy (e.g., LC3B, Atg7, Atg12) and TNF-α were increased to a greater extent in alcohol-fed aged rats. These data demonstrate that aged female rats exhibit an enhanced sensitivity to alcohol compared with adult animals. Our data are consistent with a model whereby alcohol increases proteolysis via FOXO-independent increase in atrogin-1, which degrades eIF3f and therefore impairs formation of a functional preinitiation complex and protein synthesis.

Alcohol Exacerbates LPS-Induced Fibrosis in Subclinical Acute Pancreatitis

The role of pancreatic acinar cells in initiating fibrogenic responses during the early stages of alcoholic acute pancreatitis has not been evaluated. We investigated the ability of injured acinar cells to generate pancreatic fibrosis in acute pancreatitis. Rats were fed either an ethanol-containing or control diet over 14 weeks and euthanized 3 or 24 hours after a single lipopolysaccharide injection. Profibrotic transforming growth factor-β of acinar cells and pancreatic fibrosis were assessed by immunofluorescence, histological characteristics, and electron microscopy. Human pancreatic tissues were also evaluated. Periacinar cell fibrosis and collagen were exacerbated 24 hours after endotoxemia in alcohol-fed rats. Alcohol exposure exacerbated acinar cell-specific production of transforming growth factor β in response to lipopolysaccharide in vivo and in acinar cell-like AR42J cells in vitro. Although a morphological examination showed no visible signs of necrosis, early pancreatic fibrosis can be initiated by little or no pancreatic necrosis. Transforming growth factor β was also significantly increased in human acinar cells from patients with acute/recurrent pancreatitis compared with chronic pancreatitis tissue. Alcohol exacerbates lipopolysaccharide-induced pancreatic fibrosis during the early onset of mild, subclinical, acute pancreatitis. We suggest that multiple, subclinical, acute pancreatitis episodes can accumulate in fibrosis during the development of chronic pancreatitis, even if there is no history of acute pancreatitis.

Proteolytic signaling mechanisms in skeletal muscles in patients with alcohol-induced muscle disease

Chronic alcoholic myopathy is one of most numerous and profound manifestations of chronic alcohol intoxication. This disease is characterized by the pronounced atrophy of the locomotor muscles, which involves predominantly those fibers expressing myosin isoforms of the I "fast" type. In early experiments with alcohol-fed rats and studies of patients it was shown the impairment of the anabolic intracellular signaling pathways and decrease in protein synthesis rate. We were the first to analyze the signaling pathways involved in the pathogenesis of alcoholic myopathy with different fiber atrophy levels. At the early stages of the pathogenesis we observed also the sufficient increase of mRNA of E3 ubiquitin ligases. However the ubiquitinylation level was not altered in patients as compared to the control subjects. This phenomenon could be associated with the increased expression of the heat-shock proteins, known for their protective action.

Alcohol ingestion disrupts alveolar epithelial barrier function by activation of macrophage-derived transforming growth factor beta1

BackgroundChronic alcohol abuse causes oxidative stress and impairs alveolar epithelial barrier integrity, thereby rendering the lung susceptible to acute edematous injury. Experimentally, alcohol-induced oxidative stress increases the expression of transforming growth factor β1 (TGFβ1) in the lung; however, we do not know the precise contribution of various alveolar cells in this process. In the present study, we focused on cell-cell interactions between alveolar macrophages and epithelial cells and the potential mechanisms by which TGFβ1 may become activated in the alveolar space of the alcoholic lung.MethodsPrimary alveolar macrophages and epithelial cells were isolated from control- and alcohol-fed Sprague–Dawley rats. Expression of TGFβ1 and the epithelial integrin αvβ6 were examined by real time PCR and either immunocytochemistry or flow cytometry. Alveolar epithelial cells were cultured on transwell supports in the presence of macrophage cell lysate from control- or alcohol-fed rats or in the presence of viable macrophages ± alcohol. Epithelial barrier function was assessed by transepithelial resistance (TER) and paracellular flux of Texas Red dextran.ResultsTGFβ1 expression was increased in alveolar macrophages from alcohol-fed rats, and TGFβ1 protein was predominantly membrane-bound. Importantly, alveolar macrophage cellular lysate from alcohol-fed rats decreased TER and increased paracellular dextran flux in primary alveolar epithelial cell monolayers as compared to the lysates from control-fed rats. Alcohol-induced epithelial barrier dysfunction was prevented by anti-TGFβ1 antibody treatment, indicating the presence of bioactive TGFβ1 in the macrophage lysate. In addition, co-culturing macrophages and epithelial cells in the presence of alcohol decreased epithelial barrier function, which also was prevented by anti-TGFβ1 and anti-αvβ6 treatment. In parallel, chronic alcohol ingestion in vivo, or direct treatment with active TGFβ1 in vitro, increased the expression of αvβ6 integrin, which is known to activate TGFβ1, in alveolar epithelial cells.ConclusionsTaken together, these data suggest that interactions between alveolar epithelial cells and macrophages contribute to the alcohol-mediated disruption of epithelial barrier function via the expression and activation of TGFβ1 at points of cell-cell contact.