Alcoholic Steatosis Research Articles

Mammalian Sirtuin 1 Is Involved in the Protective Action of Dietary Saturated Fat against Alcoholic Fatty Liver in Mice

This study was undertaken to elucidate the mechanism underling the protective effect of a high saturated fat (HSF) diet against the development of alcoholic fatty liver in mice. We tested the effects of a HSF diet on the ethanol-mediated increase in hepatic sterol regulatory element binding protein 1 (SREBP-1) activity. Thirty-two male mice were divided into 4 groups and fed liquid diets consisting of either a high polyunsaturated fat (40% of energy from corn oil) or a HSF (40% of energy from cocoa butter) diet with or without ethanol for 4 wk. In the ethanol-containing diets, ethanol was substituted for an equivalent amount of carbohydrate to provide 27.5% of the total energy. Control mice were pair-fed the same volume of liquid diets as the ethanol-fed mice. The HSF diet suppressed the increase in mature SREBP-1 protein and prevented increased mRNA of the SREBP-1-regulated lipogenic enzymes in the ethanol-fed mice (P < 0.05). Sirtuins 1 (SIRT1), a NAD+-dependent class III histone deacetylase, was upregulated by ethanol administration in mice fed the HSF diet (P < 0.05). The HSF diet blocked histone H3 at lysine 9 (lys9) hyperacetylation and attenuated association of acetylated histone H3-Lys9 with the promoters of mitochondrial glycerol-3-phosphate acyltransferase and stearoyl-CoA desaturase 1 in the livers of the ethanol-fed mice. These results suggest that the protective effects of HSF diet against the development of alcoholic liver steatosis may occur via regulation of the hepatic SIRT1-SREBP-1-histone H3 axis, suppressing the expression of genes encoding lipogenic enzymes and slowing the synthesis of hepatic fatty acids.

Dissection of endoplasmic reticulum stress signaling in alcoholic and non‐alcoholic liver injury

Accumulation of unfolded or malfolded proteins induces endoplasmic reticulum (ER) stress which elicits a complex network of interacting and parallel responses that dampen the stress. The ER stress response in the liver is controlled by intrinsic feedback effectors and is initially protective. However, delayed or insufficient responses or interplay with mitochondrial dysfunction may turn physiological mechanisms into pathological consequences including apoptosis, fat accumulation and inflammation all of which have an important role in the pathogenesis of liver disorders such as genetic mutations, viral hepatitis, insulin resistance, ischemia/reperfusion injury, and alcoholic and non-alcoholic steatosis. In both alcohol and non-alcohol-induced ER stress, a common candidate is hyperhomocysteinemia. Betaine supplementation and/or expression of betaine-homocysteine methyltransferase (BHMT) promote removal of homocysteine and alleviate ER stress, fatty accumulation and apoptosis in cultured hepatocytes and mouse models. The rapidity and magnitude of homocysteine-induced activation of each of the main ER resident transmembrane sensors including inositol requiring enzyme 1 (IRE-l alpha), activating transcription factor 6 (ATF-6) and RNA-activated protein kinase (PKR)-like ER kinase (PERK) appear different in different experimental models. Dissection and differentiation of ER stress signaling may reveal clues on the specific importance of the ER stress response in contributing to liver injury and thus provide better strategies on prevention and treatment of liver disease.

Cannabinoids Provoke Alcoholic Steatosis through a Conspiracy of Neighbors

Cannabinoid signaling by CB1 receptors drives fibrogenesis and fat accumulation in liver. A report in this issue of Cell Metabolism (Jeong et al., 2008) now links hepatic stellate cells, a resident liver fibrogenic cell type, to the generation of steatosis through production of the endocannabinoid 2-arachidonoylglycerol (2-AG) after ethanol feeding, leading to paracrine stimulation of hepatocyte CB1 receptors.

PXR and LXR in Hepatic Steatosis: A New Dog and an Old Dog with New Tricks

PXR was isolated as a "xenobiotic receptor" that regulates drug-metabolizing enzymes and transporters, whereas LXR is known to promote hepatic lipogenesis by activating the lipogenic transcriptional factor sterol regulatory element-binding protein (SREBP). We have recently shown that PXR can mediate a SREBP-independent lipogenic pathway by activating the free fatty acid (FFA) uptake transporter CD36, PPARgamma, and several accessory lipogenic enzymes, such as stearoyl CoA desaturase-1 (SCD-1) and long-chain free fatty acid elongase (FAE). More recently, we found activation of LXR also induced the expression of CD36. Promoter analysis established CD36 as a novel transcriptional target of LXRalpha. Moreover, the steatotic effect of LXR agonists was largely abolished in CD36 null mice, suggesting an essential role for CD36 and FFA uptake in LXR-mediated steatosis. We also showed that PPARgamma, a positive regulator of CD36, is also a transcriptional target of PXR. Thus, PXR can regulate CD36 directly or through its activation of PPARgamma. Interestingly, PXR- and LXR-mediated CD36 activation and PXR-mediated PPARgamma activation are all liver-specific. We conclude that CD36 is a shared target of LXR, PXR, and PPARgamma. The network of CD36 regulation controlled by LXR, PXR, and PPARgamma establishes this FFA transporter as a common target of orphan nuclear receptors in their mediation of hepatic steatosis. It is hoped that the nuclear receptor-mediated CD36 regulation may offer novel targets for the therapeutic management of alcoholic and nonalcoholic steatosis.

Serum ferritin and erythrocyte indices in iron overload.

Raised levels of serum transferrin saturation (TS) and ferritin (SF) are frequently associated with increased values of haemoglobin and erythrocyte indices. In hereditary haemochromatosis this phenomenon has been considered to be a beneficial effect of the C282Y mutation, protecting women from iron deficiency. The elevated values of mean corpuscular volume (MCV) in hereditary haemochromatosis may reflect increased iron uptake and haemoglobin synthesis by immature erythroid cells1–3. In a large screening study of a European population, a higher haemoglobin concentration was found in C282Y homozygous women with either normal or increased TS or SF4. However, when the effect of the C282Y mutation was analysed separately in subjects from different parts of Europe, the mean haemoglobin concentration and MCV were higher in C282Y carriers from northern Europe than in those from southern Europe. This could be due to the higher prevalence of thalassaemia trait in southern Europe5. The variability in TS and SF may depend not only on mutations in HFE or other genes involved in haemochromatosis, but also on other genetic and environmental factors. A recent large screening study (the HEIRS study) conducted in the USA and in Canada found higher mean TS and SF levels among Asians and Pacific Islanders, who do not have an HFE mutation or H63D allele, than in white subjects. There is no consistent evidence supporting the hypothesis that the increased SF in Asians is attributable to liver disease or diabetes. A reduced MCV in Asian men with increased SF could be explained by a high prevalence of thalassaemia trait in this population, although further studies are required to clarify this issue6. In anaemia of chronic diseases (ACD), normal or increased SF and reduced TS levels are usually associated with low haemoglobin levels and normocytic or microcytic erythrocytes. An increased uptake of iron and retention in active macrophages, which is the pathophysiological mechanism of ACD, is linked to increased pro-inflammatory and anti-inflammatory cytokines and is responsible for reduced availability of iron for erythroid progenitors. Recently, it was speculated that a small peptide hormone, hepcidin, might be involved in the pathogenesis of ACD. Hepcidin has antimicrobial activity and its expression increases in response to inflammatory stimuli. In mice, hepcidin mRNA expression is increased in response to lipopolysaccharides and infection. It has been suggested that hepcidin may be one cytokine-regulated gene that impairs erythrocyte iron acquisition by modifying the release of iron from macrophages7. In alcoholic steatosis, the serum TS and SF levels are unrelated to iron deposits. In alcoholic cirrhosis, low haemoglobin concentrations and increased MCV are often detected in association with increased levels of ferritin. These haematological findings are dependent on several factors, including direct and indirect effects of alcohol on the bone marrow, an impaired nutritional state, and the different stages of the liver disease. Hyperferritinaemia is also frequently observed in non-alcoholic fatty liver disease (NAFLD), the hepatic manifestation of the metabolic syndrome. The increased SF values are associated with insulin resistance and mild hepatic iron accumulation. So far, no significant modifications of haematological indices have been reported in NAFLD8.

Mechanisms of protection by the betaine-homocysteine methyltransferase/betaine system in HepG2 cells and primary mouse hepatocytes

Betaine-homocysteine methyltransferase (BHMT) regulates homocysteine levels in the liver. We previously reported that the alteration of BHMT is associated with alcoholic liver steatosis and injury. In this study, we tested whether BHMT protects hepatocytes from homocysteine-induced injury and lipid accumulation. Both BHMT transfectants of HepG2 cells and primary mouse hepatocytes with suppressed BHMT were generated. Comparisons were made between the cell models with respect to their response to homocysteine treatments. Homocysteine metabolism was impaired in HepG2 cells, and the expression of BHMT in HepG2 cells ameliorated the impairment and stabilized the levels of intracellular homocysteine after the addition of exogenous homocysteine. BHMT expression inhibited homocysteine-induced glucose-regulated protein 78 (GRP78) and C/EBP-homologous protein (CHOP) and homocysteine-induced cell death. A betaine treatment protected primary mouse hepatocytes from a homocysteine-induced increase in GRP78 and cell death but not a tunicamycin-induced increase. Homocysteine induced greater CHOP expression (2.7-fold) in BHMT small interfering RNA (siRNA)-transfected cells than in a control (1.9-fold). Homocysteine-induced cell death was increased by 40% in the siRNA-treated cells in comparison with the control. Apolipoprotein B (apoB) expression was higher and triglycerides and cholesterol were lower in HepG2 expressing BHMT. In primary mouse hepatocytes, homocysteine induced the accumulation of triglycerides and cholesterol, which was reduced in the presence of betaine. Betaine partially reduced homocysteine-induced sterol regulatory element binding protein 1 expression in HepG2 cells and increased S-adenosylmethionine in primary mouse hepatocytes. The BHMT/betaine system directly protects hepatocytes from homocysteine-induced injury but not tunicamycin-induced injury, including an endoplasmic reticulum stress response, lipid accumulation, and cell death. This system also exhibits a more generalized effect on liver lipids by inducing ApoB expression and increasing S-adenosylmethionine/S-adenosylhomocysteine.

Traditional Chinese herbal medicines for treatment of liver fibrosis and cancer: from laboratory discovery to clinical evaluation

Liver disease afflicts over 10% of the world population. This includes chronic hepatitis, alcoholic steatosis, fibrosis, cirrhosis and hepatocellular carcinoma (HCC), which are the most health-threatening conditions drawing considerable attention from medical professionals and scientists. Patients with alcoholism or viral hepatitis are much more likely to have liver cell damage and cirrhosis, and some may eventually develop HCC, which is unfortunately, and very often, a fatal malignancy without cure. While liver surgery is not suitable in many of the HCC cases, patients are mostly given palliative support cares or transarterial chemoembolization or systemic chemotherapies. However, HCC is well known to be a highly chemoresistant tumour, and the response rate is <10-20%. To this end, alternative medicines are being actively sought from other sources with hopes to halt the disease's progression or even eliminate the tumours. Traditional Chinese herbal medicine has begun to gain popularity worldwide for promoting healthcare as well as disease prevention, and been used as conventional or complementary medicines for both treatable and incurable diseases in Asia and the West. In this article, we discuss the laboratory findings and clinical trial studies of Chinese herbal medicines (particularly small molecule compounds) for the treatment of liver disease ranging from fibrosis to liver cancer.

Combined metadoxine and garlic oil treatment efficaciously abrogates alcoholic steatosis and CYP2E1 induction in rat liver with restoration of AMPK activity

Alcoholic steatosis is the earliest and most common response to heavy alcohol intake, and may precede more severe forms of liver injury. Accumulation of fat, largely triglyceride, in hepatocytes results from the inhibition of fatty acid oxidation and excessive oxidative stress involving CYP2E1. This study evaluated the therapeutic effects of metadoxine, garlic oil or their combination on alcoholic steatosis. Feeding rats an alcohol-containing diet for 4 weeks elicited an increase in hepatic triglyceride content and induced CYP2E1. The concurrent administration of metadoxine and garlic oil (MG) to rats during the last week of the diet feeding efficaciously abrogated both fat accumulation and CYP2E1 induction as compared to the individual treatment at higher doses. Histopathology confirmed the ability of MG combination to inhibit lipid accumulation. Blood biochemistry verified improvement of liver function in rats treated with MG. Alcohol administration resulted in a decrease in AMP-activated protein kinase-α (AMPKα) phosphorylation, which was restored by MG treatments. Recovery of AMPK activity by MG was supported by an increase in acetyl-CoA carboxylase phosphorylation. Hepatic fatty acid synthase (FAS) expression was markedly decreased after alcohol consumption, which correlated with a decrease in AMPK activity and a commensurate increase in lipid content. Combined MG treatments caused restoration of the FAS level. These results demonstrate that the combination of MG effectively treats alcoholic steatosis with CYP2E1 inhibition, which may be associated with the recovery of AMPK activity, promising that the combination therapy may constitute an advance in the development of clinical candidates for alcoholic steatosis.

S‐Adenosylmethionine Attenuates Hepatic Lipid Synthesis in Micropigs Fed Ethanol With a Folate‐Deficient Diet

To demonstrate a causative role of abnormal methionine metabolism in the pathogenesis of alcoholic steatosis, we measured the effects on hepatic lipid synthesis of supplementing ethanol and folate-deficient diets with S-adenosylmethionine (SAM), a metabolite that regulates methionine metabolism. Yucatan micropigs were fed folate-deficient diets as control, with ethanol at 40% of kcal, and with ethanol supplemented with SAM at 0.4 g/1,000 kcal for 14 weeks. Histopathology, triglyceride levels and transcripts, and protein levels of the regulatory signals of hepatic lipid synthesis were measured in terminal omental adipose and liver samples. Feeding ethanol at 40% of kcal with folate-deficient diets for 14 weeks increased and supplemental SAM maintained control levels of liver and plasma triglyceride. Serum adiponectin, liver transcripts of adiponectin receptor-1 (AdipoR1), and phosphorylated adenosine monophosphate kinase-beta (p-AMPKbeta) were each reduced by ethanol feeding and were sustained at normal levels by SAM supplementation of the ethanol diets. Ethanol feeding activated and SAM supplementation maintained control levels of ER stress-induced transcription factor sterol regulatory element-binding protein-1c (SREBP-1c) and its targeted transcripts of lipid synthesizing enzymes acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), and glycerol-3-phosphate acyltransferase (GPAT). Ethanol feeding with a folate-deficient diet stimulates hepatic lipid synthesis by down-regulating adiponectin-mediated pathways of p-AMPK to increase the expression of nSREBP-1c and its targeted lipogenic enzymes. Preventing abnormal hepatic methionine metabolism by supplementing ethanol diets with SAM reduces liver triglyceride levels by up-regulation of adiponectin-mediated pathways to decrease fatty acid and triglyceride synthesis. This study demonstrates that ethanol-induced hepatic lipid synthesis is mediated in part by abnormal methionine metabolism, and strengthens the concept that altered methionine metabolism plays an integral role in the pathogenesis of steatosis.

Co-infection avec les hépatites virales

k]HBV and HCV infections are frequent in HIV patients and often contribute significantly to mortality and morbidity. There is no evidence that either HCV or HBV affects HIV disease progression. By contrast, HIV increases HBV and HCV viral replication and leads to higher chronicity rates. It also increases mother-to-child and sexual HCV transmission. HIV speeds the course of HCV and HBV liver disease progression, resulting in accelerated liver fibrosis progression and increased rates of liver decompensation, cirrhosis and hepatocellular carcinoma. Coinfected patients are more likely to have other fibrosis cofactors, such as high alcohol consumption and steatosis. All HIV-infected patients should undergo regular screening for HCV and HBV, using a real-time PCR detection system for HCV RNA and HBV DNA, when possible. Liver damage should be evaluated using liver biopsy or noninvasive methods, such as serum fibrosis marker assays and tissue elastography. HBV and HCV increase HIV drug toxicity. Antiretroviral therapy (ART) has a positive effect on HCV and HBV disease. Didanosine, stavudine and zidovudine should be avoided in HIV treatment in the case of HCV combination therapy with pegylated interferon and ribavirin. Sustained virological response (SVR) is lower in coinfected patients compared with monoinfected patients. Every effort, however, should be made to maintain high-dose therapy, which results in improved SVR. HBV treatment is mainly based on nucleoside/nucleotide analogues. Liver transplantation can be performed in coinfected patients with decompensated cirrhosis. Hepatitis prevention by vaccination against HBV and HAV should be widely considered in the care of HIV-infected patients.

Liver transplantation worldwide

Liver transplantation worldwide

Betaine attenuates alcoholic steatosis by restoring phosphatidylcholine generation via the phosphatidylethanolamine methyltransferase pathway

Previous studies in our laboratory implicated ethanol-induced decreases in hepatocellular S-adenosylmethionine to S-adenosylhomocysteine (SAM:SAH) ratios in lowering the activity of phosphatidylethanolamine methyltransferase (PEMT), which is associated with the generation of steatosis. Further in vitro studies showed that betaine supplementation could correct these alterations in the ratio as well as attenuate alcoholic steatosis. Therefore, we sought to determine whether the protective effect of betaine is via its effect on PEMT activity. Male Wistar rats were fed the Lieber DeCarli control or ethanol diet with or without 1% betaine supplementation for 4 weeks. We observed that ethanol feeding resulted in decreased phosphatidylcholine (PC) production by a PEMT-catalyzed reaction. Betaine supplementation corrected the ethanol-induced decrease in hepatic SAM:SAH ratios and by normalizing PC production via the PEMT-mediated pathway, significantly reduced fatty infiltration associated with ethanol consumption. This restoration of hepatocellular SAM:SAH ratio by betaine supplementation was associated with increases in the activity, enzyme mass and gene expression of the enzyme, betaine homocysteine methyltransferase (BHMT), that remethylates homocysteine. Betaine, by virtue of promoting an alternate remethylation pathway, restores SAM:SAH ratios that, in turn, correct the defective cellular methylation reaction catalyzed by PEMT resulting in protection against the generation of alcoholic steatosis.

Anabolic-androgenic steroids for alcoholic liver disease.

Alcohol is one of the most common causes of liver disease in the Western World. Randomised clinical trials have examined the effects of anabolic-androgenic steroids for alcoholic liver disease. To assess the beneficial and harmful effects of anabolic-androgenic steroids for patients with alcoholic liver disease based on the results of randomised clinical trials. We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Controlled Trials Register in The Cochrane Library, MEDLINE, EMBASE, LILACS, and Science Citation Index Expanded until June 2006. Electronic searches were combined with full text searches. Manufacturers and researchers in the field were also contacted. Randomised clinical trials studying patients with alcoholic steatosis, alcoholic fibrosis, alcoholic hepatitis, and/or alcoholic cirrhosis were included. Interventions encompassed anabolic-androgenic steroids at any dose or duration versus placebo or no intervention. The trials could be double blind, single blind, or unblinded. The trials could be unpublished or published, and no language limitations were applied. Outcomes are assessed at maximal follow-up. All analyses were performed according to the intention-to-treat method. The statistical package RevMan Analyses was used. The methodological quality of the randomised clinical trials was assessed. Combining the results of five randomised clinical trials randomising 499 patients with alcoholic hepatitis and/or cirrhosis demonstrated no significant effects of anabolic-androgenic steroids on mortality (relative risk (RR) 1.01, 95% confidence interval (CI) 0.79 to 1.29), liver-related mortality (RR 0.83, 95% CI 0.60 to 1.15), complications of liver disease (RR 1.25, 95% CI 0.74 to 2.10), and liver histology. Anabolic-androgenic steroids did not significantly affect a number of other outcome measures, including sexual function and liver biochemistry. Anabolic-androgenic steroids were not associated with a significantly increased risk of non-serious adverse events (RR 1.14, 95% CI 0.50 to 2.59) or with serious adverse events (RR 4.54, 95% CI 0.57 to 36.30). This systematic review could not demonstrate any significant beneficial effects of anabolic-androgenic steroids on any clinically important outcomes (mortality, liver-related mortality, liver complications, and histology) of patients with alcoholic liver disease.

Identification and Characterization of Associated with Lipid Droplet Protein 1: A Novel Membrane‐Associated Protein That Resides on Hepatic Lipid Droplets

Alcoholic and nonalcoholic liver steatosis and steatohepatitis are characterized by the massive accumulation of lipid droplets (LDs) in the cytosol of hepatocytes. Although LDs are ubiquitous and dynamic organelles found in the cells of a wide range of organisms, little is known about the mechanisms and sites of LD biogenesis. To examine the participation of these organelles in the pathophysiological disorders of steatotic livers, we used a combination of mass spectrometry (matrix-assisted laser desorption ionization-time of flight and LC-MS electrospray) and Western blot analysis to study the composition of LDs purified from rat liver after a partial hepatectomy. Fifty proteins were identified. Adipose differentiation-related protein was the most abundant, but other proteins such as calreticulin, TIP47, Sar1, Rab GTPases, Rho and actin were also found. In addition, we identified protein associated with lipid droplets I ALDI (tentatively named Associated with LD protein 1), a novel protein widely expressed in liver and kidney corresponding to the product of 0610006F02Rik (GI:27229118). Our results show that, upon lipid loading of the cells, ALDI translocates from the endoplasmic reticulum into nascent LDs and indicate that ALDI may be targeted to the initial lipid deposits that eventually form these droplets. Moreover, we used ALDI expression studies to view other processes related to these droplets, such as LD biogenesis, and to analyze LD dynamics. In conclusion, here we report the composition of hepatic LDs and describe a novel bona fide LD-associated protein that may provide new insights into the mechanisms and sites of LD biogenesis.

Metabolic basis of ethanol-induced hepatic and pancreatic injury in hepatic alcohol dehydrogenase deficient deer mice

Alcoholic liver disease (ALD) and alcoholic pancreatitis (AP) are major diseases causing high mortality and morbidity among chronic alcohol abusers. Neutral lipid accumulation (steatosis) is an early stage of ALD or AP and progresses to inflammation and other advanced stages of diseases in a subset of chronic alcohol abusers. However, the mechanisms of alcoholic steatosis leading to ALD and AP are not well understood. Chronic alcohol abuse impairs hepatic alcohol dehydrogenase (ADH, a major enzyme involved in ethanol oxidative metabolism) and facilitates nonoxidative metabolism of ethanol to fatty acid ethyl esters (FAEEs, nonoxidative metabolites of ethanol). These esters are implicated in the pathogenesis of various alcoholic diseases and shown to cause hepatocellular and pancreatitis-like injury. Ethanol exposure is known to increase synthesis of FAEEs by several-fold in the livers and pancreata of rats pretreated with hepatic ADH inhibitor. Therefore, studies were undertaken to evaluate hepatocellular and pancreatic injury in hepatic ADH-deficient (ADH −) deer mice versus ADH-normal (ADH +) deer mice fed ethanol (4% wt/vol) via Lieber-DeCarli liquid diet for 60 days. A significant mortality was found in ethanol-fed ADH − deer mice (11 out of 18) versus ADH + deer mice (1 out of 16); most of the deaths occurred during the first 2 weeks of ethanol exposure. The surviving animals, sacrificed at the end of 60th day, showed distinct changes in hepatic and pancreatic histology and several-fold increases in nonoxidative metabolism of ethanol in ethanol-fed ADH − versus ADH + deer mice. Extensive vacuolization with displacement or absence of nucleus in some hepatocytes, and significant increase in hepatic neutral lipids were found in ethanol-fed ADH − versus ADH + deer mice. Ultrastructural changes showed perinuclear space, edema, presence of apoptotic bodies and disintegration, and/or dilatation of endoplasmic reticulum (ER) in the pancreata of ethanol-fed ADH − deer mice. FAEE levels were significantly higher in ADH − versus ADH + deer mice, approximately four-fold increases in the livers and seven-fold increases in the pancreata. Ethyl esters of oleic, linoleic, and arachidonic acids were the major FAEEs detected in ethanol-fed groups. The role of FAEEs in pancreatic lysosomal fragility is reflected by higher activity of cathepsin B (five-fold) in ethanol-fed ADH − versus ADH + deer mice. Although the present studies clearly indicate a metabolic basis of ethanol-induced hepatic and pancreatic injury, detailed dose- and time-dependent toxicity studies in this ADH − deer mouse model could reveal further a better understanding of mechanism(s) of ethanol-induced hepatic and pancreatic injuries.

Intrahepatic gene expression in human alcoholic hepatitis

Alcoholic hepatitis remains an important cause of morbidity and mortality. Treatment remains unsatisfactory, in part, due to limited understanding of the pathogenesis. The aim of this study is to define the global intrahepatic expression profile of human alcoholic hepatitis. Gene expression was analysed by DNA microarray on RNA isolated from liver of patients with alcoholic hepatitis (AH, n = 8), alcoholic steatosis (AS, n = 9) and explants from non-diseased donor liver controls (ND, n = 7). Differential expression of selected genes was confirmed by real-time RT-PCR and immunohistochemistry. Cluster analysis allowed differentiation of alcoholic hepatitis from alcoholic steatosis. The gene expression profile of AH revealed 586 genes differentially expressed from AS and 211 genes differentially expressed from that of ND liver. In comparison, only 98 genes were differentially expressed in AS from ND. Novel differentially expressed genes in AH in comparison to ND and AS included claudins, osteopontin, CD209, selenoprotein and genes related to bile duct proliferation. Real-time RT-PCR confirmed up-regulation of IL-8, osteopontin, and TNFRSF14 and down-regulation of SAMeS and CD209. This study has defined the intrahepatic gene expression profile of human alcoholic hepatitis and revealed a number of novel differentially expressed genes.

Relationship Between Steatosis, Inflammation, and Fibrosis in Chronic Hepatitis C: A Meta-Analysis of Individual Patient Data

Steatosis is a frequent histologic finding in chronic hepatitis C (CHC), but it is unclear whether steatosis is an independent predictor for liver fibrosis. We evaluated the association between steatosis and fibrosis and their common correlates in persons with CHC and in subgroup analyses according to hepatitis C virus (HCV) genotype and body mass index. We conducted a meta-analysis on individual data from 3068 patients with histologically confirmed CHC recruited from 10 clinical centers in Italy, Switzerland, France, Australia, and the United States. Steatosis was present in 1561 patients (50.9%) and fibrosis in 2688 (87.6%). HCV genotype was 1 in 1694 cases (55.2%), 2 in 563 (18.4%), 3 in 669 (21.8%), and 4 in 142 (4.6%). By stepwise logistic regression, steatosis was associated independently with genotype 3, the presence of fibrosis, diabetes, hepatic inflammation, ongoing alcohol abuse, higher body mass index, and older age. Fibrosis was associated independently with inflammatory activity, steatosis, male sex, and older age, whereas HCV genotype 2 was associated with reduced fibrosis. In the subgroup analyses, the association between steatosis and fibrosis invariably was dependent on a simultaneous association between steatosis and hepatic inflammation. In this large and geographically different group of CHC patients, steatosis is confirmed as significantly and independently associated with fibrosis in CHC. Hepatic inflammation may mediate fibrogenesis in patients with liver steatosis. Control of metabolic factors (such as overweight, via lifestyle adjustments) appears important in the management of CHC.

Dietary Conjugated Linoleic Acid (CLA) Attenuates Hepatic Steatosis by Modifying Stearoyl‐CoA Desaturase (SCD‐1) mRNA and Activity in High‐Fat‐Fed Rats

Non alcoholic hepatic steatosis is associated with obesity and may lead to insulin resistance. Isomers of CLA are naturally occurring dietary compounds with health promoting effects. The role of CLA in attenuating hepatic steatosis and hyperglycemia is complex. Here, we investigated the extent that CLA protects male Wistar rats from developing hepatic steatosis. Rats were fed a 20% fat diet for 4 weeks then changed to either control (CON) diet or CLA diet containing 6.5% soybean oil or 5% soybean oil plus 1.5% CLA respectively. After 4 weeks, CLA diet did not change food intake or body weight however fasting blood glucose (FBG) and hepatic triglycerides (TG) were significantly reduced compared to CON group. Reduced TG levels were associated with significantly lower SCD-1 mRNA levels measured by real time PCR and SCD-1 activity which was determined by gas chromatography. As the rate-limiting enzyme in the cellular biosynthesis of oleate and palmitoleate, SCD-1 activity is indicative of synthesis of components of TG, phospholipids and cholesterol. The effects of CLA on SCD-1 were independent of the adipocytokine, leptin, which was unchanged in rats fed CLA. Because leptin is known to suppress SCD-1, these data suggest CLA acts in part as a leptin mimetic. The mRNA levels of gluconeogenic enzymes were unchanged in the CLA fed group. Thus, the lower hepatic lipid accumulation may be modulated by SCD-1 independent of changes on adipose or leptin levels. We anticipate these hepatic effects explain the improvement of glucose levels in Wistar rats fed CLA. This work was supported by the USDA.

Letter Regarding Article by Ruttmann et al, “γ-Glutamyltransferase as a Risk Factor for Cardiovascular Disease Mortality: An Epidemiological Investigation in a Cohort of 163 944 Austrian Adults”

To the Editor: In their article, Ruttmann et al1 showed that γ-glutamyltransferase(GGT) was independently associated with cardiovascular (CV) mortality. GGT was significantly correlated with components of the metabolic syndrome,2 including uric acid level, but waist circumference was not measured. Measurement of GGT activity is a very commonly used diagnostic test for liver dysfunction, and it increases with alcohol consumption and steatosis. Elevation of hepatic enzyme activities occurs frequently in patients with multiple CV risk factors. Indeed, we have shown that approximately one fourth of a population of 8501 dyslipidemic patients3 displayed hepatic enzymatic elevations. We found correlation coefficients similar to those reported by Ruttmann et al1 when GGT, aspartate aminotransferase, or alanine aminotransferase was selected. In subgroup analysis, the relation between waist circumference, body mass index (BMI), and GGT (n=1911) was …

Progression of hepatic fibrosis in irish females with HCV infection (genotype 1) – the impact of menopause

Introduction: Liver fibrosis is known to be highly variable within HCV infected cohorts. Co-factors for fibrosis progression include alcohol excess, steatosis and viral co-infection. Recent data suggest that low oestrogen and menopause are associated with accelerated fibrosis. This has not been validated in patients with paired biopsies.