MyD88 in hepatic stellate cells promotes the development of alcoholic fatty liver via the AKT pathway

Myeloid differentiation primary response gene 88 (MyD88), an adaptor protein in the Toll-like receptors (TLRs) signalling pathway, is expressed in various liver cells including hepatocytes, Kupffer cells and hepatic stellate cells (HSCs). And yet, the functional role of MyD88 in HSCs is poorly elucidated in alcoholic fatty liver (AFL). Here, to study the functional role of MyD88 in HSCs and the molecular mechanism related to the development of AFL, chronic-binge ethanol mouse models were established in mice with specific MyD88 knockout in quiescent (MyD88^GFAP-KO) and activated HSCs (MyD88^SMA-KO), respectively. Our results clearly showed an elevated expression of MyD88 in liver tissues of ethanol treated mouse model which harbours the wild type. Intriguingly, ethanol treatment profoundly inhibited inflammation in both MyD88^GFAP-KO and MyD88^SMA-KO mice, but the suppression of lipogenesis was only observed in MyD88^GFAP-KO mice. Molecularly, our study indicated that MyD88 induced osteopontin (OPN) secretion in HSCs, which consequently resulted in activation of AKT signalling pathway and accumulation of fat in hepatocytes. Additionally, our data also suggested that OPN promoted inflammation by activating p-STAT1. Thus, targeting MyD88 may be a potentially represent a promising strategy for the prevention and treatment of AFL. KEY MESSAGES: The expression of MyD88 in HSCs was significantly increased in ethanol-induced liver tissues of wild-type mice. MyD88 deficiency in quiescent HSCs inhibited inflammation and lipogenesis under the ethanol feeding condition. MyD88 deficiency in activated HSCs only inhibited inflammation under the ethanol feeding condition. MyD88 promoted the OPN secretion of HSCs, which further activated the AKT signalling pathway of hepatocytes and upregulated lipogenic gene expression to promote fat accumulation. OPN also promotes inflammation by activating p-STAT1.

The impact of Model for End-Stage Liver Disease score on deceased donor liver transplant outcomes in low volume liver transplantation center: a retrospective and single-center study

PURPOSE

In June 2016, the Model for End-Stage Liver Disease (MELD) score was employed in South Korea instead of the Child-Turcotte-Pugh (CTP) score. This study compared the outcomes of deceased donor liver transplantation (DDLT) before and after the MELD system application.

METHODS

This retrospective study reviewed 48 patients who underwent DDLT for end-stage liver disease at a single tertiary referral center between January 2014 and December 2018. The patients were categorized into the pre-MELD (22 patients) and post-MELD (26 patients) groups. The demographics, postoperative outcomes, and overall survival time were evaluated between the 2 groups.

RESULTS

The 2 groups had no differences in age, sex, ABO type, etiology for liver transplantation, CTP-score, operation time, cold ischemic time, and amount of red blood cell transfusion, although their MELD score differed significantly (post-MELD group, 36.2 ± 4.9; pre-MELD group, 27.7 ± 11.8; P < 0.001). The post-MELD group has longer intensive care unit stay (11.2 ± 9.5 days vs. 5.7 ± 4.5 days, P = 0.018) and hospital stay than the pre-MELD group (36.8 ± 26 days vs. 22.8 ± 9.3 days, P = 0.016). The 1-year survival rate was lower in the post-MELD group (61.5% vs. 86.4%, P = 0.029).

CONCLUSION

After MELD allocation, patients with high MELD scores had increased DDLT and consequently required a longer recovery time, which could negatively affect survival. According to the experience of a small-volume center, these problems were related to both severe organ shortages in South Korea and MELD allocation.

Caveolin-1 attenuates acetaminophen aggravated lipid accumulation in alcoholic fatty liver by activating mitophagy via the Pink-1/Parkin pathway

Alcoholic fatty liver (AFL) is a disease characterized by the abnormal structure and dysfunction of hepatocytes caused by long-term, excessive drinking. Acetaminophen (APAP) is a commonly used painkiller, but it can aggravate lipid deposition in the liver and cause liver injury when used in fatty liver disease. Here, we investigated the effect of caveolin-1 (CAV-1), an intracellular stent protein, on the pathogenesis of APAP aggravated lipid deposition in AFL mice. This study shows that lipid accumulation was more severe in APAP groups than in alcohol-treated mice. The CAV-1 stent-like domain (CSD, 82-101 amino acids of caveolin-1), used to upregulate CAV-1 expression, could reduce lipid accumulation and activate autophagy in AFL mice treated with APAP. The levels of CAV-1 and autophagy-related proteins (LC3-II/I and Beclin-1) had decreased, whereas SREBP-1c had increased in A/O (alcohol and oleic acid) and APAP-co-treated L02 cells. CAV-1 small interfering RNA and CAV1-overexpressing plasmid were separately transfected into A/O and APAP co-treated L02 cells. When CAV-1 was downregulated, the levels of Pink-1, Parkin, and autophagy-related proteins (LC3-II/I and Beclin-1) were decreased, whereas SREBP-1c was increased. The opposite trend was observed when CAV-1 was overexpressed. The results show that CAV-1 reduced lipid accumulation in L02 cells and activated Pink-1/Parkin-related mitophagy. This study highlights the positive role of CAV-1 in APAP-increased lipid accumulation under the AFL status and provides a new understanding of the function of CAV-1 in the liver through mitophagy associated with the Pink-1/Parkin pathway.

Association of Cardiovascular Risk Factors and Metabolic Syndrome with non-alcoholic and alcoholic fatty liver disease: a retrospective analysis

BACKGROUND

Although many studies on non-alcoholic fatty liver disease (NAFLD) are underway worldwide, and several existing studies have investigated the association between NAFLD and cardiovascular risk factors, studies comparing NAFLD and alcoholic fatty liver disease (AFLD) are scarce. This study aimed to evaluate differences between the incidence of cardiovascular risk factors and metabolic syndrome in NAFLD and AFLD.

METHODS

A retrospective analysis of 913 patients who underwent abdominal computed tomography (CT) was performed to compare the incidence of cardiovascular risk factors and metabolic syndrome between NAFLD and AFLD. Subjects were divided into three groups based on criteria: healthy (n = 572), NAFLD (n = 295), and AFLD (n = 46). The healthy group had no liver disease. NAFLD was defined as fatty liver diagnosed on CT and drinking less than 140 g/week for men or 70 g/week for women. AFLD was defined as fatty liver diagnosed on CT and drinking more than 140 g/week for men or 70 g/week for women. We compared the incidence of cardiovascular risk factors and metabolic syndrome between the three groups. The relationship between each group and the metabolic syndrome risk was analyzed through multivariate logistic regression analysis.

RESULTS

No significant differences in several cardiovascular risk factors were observed between the NAFLD and AFLD groups. Upon analyzing the metabolic syndrome status in each group after making appropriate adjustments, the odds ratios (ORs) in the NAFLD (OR = 2.397, P = 0.002) and AFLD groups (OR = 4.445, P = 0.001) were found to be significantly higher than that in the healthy group; the incidence rate of metabolic syndrome was similar in the NAFLD and AFLD groups.

CONCLUSIONS

Both the NAFLD and AFLD groups had more cardiovascular risk factors and higher metabolic syndrome risk than the healthy group. Thus, the prevention of fatty liver disease, regardless of the specific type, should involve the identification of cardiovascular and metabolic syndrome risk factors. If abdominal CT reveals a fatty liver, whether NAFLD or AFLD, the risk of cardiovascular disease and metabolic syndrome should be assessed.

Mesencephalic astrocyte-derived neurotrophic factor alleviates alcohol induced hepatic steatosis via activating Stat3-mediated autophagy

Alcoholic fatty liver disease (AFLD) is induced by alcohol consumption and may progress to more severe liver diseases such as alcoholic steatohepatitis, fibrosis and cirrhosis, and even hepatocellular carcinoma. Mesencephalic astrocyte-derived neurotrophic factor (MANF) participates in maintaining lipid homeostasis. However, the role of MANF in the pathogenesis of AFLD remains unclear. We established an AFLD mouse model following the US National Institute on Alcohol Abuse and Alcoholism procedure. Both mRNA and protein levels of MANF were significantly increased in the chronic binge alcohol feeding model. Liver-specific knockout of MANF aggravated hepatic lipid accumulation. Similarly, liver-specific overexpression of MANF alleviated AFLD in mouse livers. MANF affected hepatic lipid metabolism by modulating autophagy. The levels of LC3-II and Atg5-Atg12 were decreased in mouse livers with MANF liver-specific knockout and increased with MANF liver-specific overexpression. Furthermore, MANF changed the phosphorylation of Stat3 and its nuclear localization. MANF may have a protective role in the development of AFLD.

Downregulation of mitogen-activated protein kinases (MAPKs) in chronic ethanol-induced fatty liver

Mitogen-activated protein kinases (MAPKs) are versatile proteins that have been suggested to be involved in the regulation of lipid metabolism. This study was designed to investigate the responses of MAPK signaling to chronic ethanol exposure in vivo and in vitro, and try to explore its role in the pathogenesis of alcoholic fatty liver (AFL). Mice were fed with Lieber-Decarli liquid diet (5% ethanol, w/v) for 4 weeks to induce fatty liver, and the chronological changes of MAPK phosphorylation were measured using western blotting. We found that chronic ethanol feeding led to accumulation of triglyceride (TG), decreased phosphorylation of MAPKs, decreased protein level of peroxisomal proliferator activation receptor α (PPARα), and increased protein expression of cytochrome P4502E1 (CYP2E1) in mice liver. In vitro study showed that overexpression of CYP2E1 blunted the response of MAPKs to ethanol, and MAPK phosphatase 1 (MKP-1) knockdown by siRNA led to upregulation of PPARα protein level. Lastly, epidermal growth factor (EGF), a well-known MAPK activator, significantly suppressed chronic ethanol-induced hepatic fat accumulation and decline of PPARα expression in mice liver. Collectively, MAPK suppression, possibly due to the activation of hepatic CYP2E1, may be involved in chronic ethanol-induced hepatic steatosis.

Ghrelin regulates adipose tissue metabolism: Role in hepatic steatosis

Fatty liver is the earliest and most common response of the liver to consumption of excessive alcohol. Steatosis can predispose the fatty liver to develop progressive liver damage. Chief among the many mechanisms involved in development of hepatic steatosis is dysregulation of insulin-mediated adipose tissue metabolism. Particularly, it is the enhanced adipose lipolysis-derived free fatty acids and their delivery to the liver that ultimately results in hepatic steatosis. The adipose-liver axis is modulated by hormones, particularly insulin and adiponectin. In recent studies, we demonstrated that an alcohol-induced increase in serum ghrelin levels impairs insulin secretion from pancreatic β-cells. The consequent reduction in circulating insulin levels promotes adipose lipolysis and mobilization of fatty acids to the liver to ultimately contribute to hepatic steatosis. Because many tissues, including adipose tissue, express ghrelin receptor we hypothesized that ghrelin may directly affect energy metabolism in adipocytes. We have exciting new preliminary data which shows that treatment of premature 3T3-L1 adipocytes with ghrelin impairs adipocyte differentiation and inhibits lipid accumulation in the tissue designed to store energy in the form of fat. We further observed that ghrelin treatment of differentiated adipocytes significantly inhibited secretion of adiponectin, a hepatoprotective hormone that reduces lipid synthesis and promotes lipid oxidation. These results were corroborated by our observations of a significant increase in serum adiponectin levels in ethanol-fed rats treated with a ghrelin receptor antagonist verses the un-treated ethanol-fed rats. Interestingly, in adipocytes, ghrelin also increases secretion of interleukin-6 (IL-6) and CCL2 (chemokine [C-C motif] ligand 2), cytokines which promote hepatic inflammation and progression of liver disease. To summarize, the alcohol-induced increase in serum ghrelin levels dysregulates adipose-liver interaction and promotes hepatic steatosis by increasing the free fatty acid released from adipose for hepatic uptake, and by altering adiponectin and cytokine secretion. Taken together, our data indicates that targeting the activity of ghrelin may be a powerful treatment strategy.

Estrogen-related receptor γ controls sterol regulatory element-binding protein-1c expression and alcoholic fatty liver

Although SREBP-1c regulates key enzymes required for hepatic de novo lipogenesis, the mechanisms underlying transcriptional regulation of SREBP-1c in pathogenesis of alcoholic fatty liver is still incompletely understood. In this study, we investigated the role of ERRγ in alcohol-mediated hepatic lipogenesis and examined the possibility to ameliorate alcoholic fatty liver through its inverse agonist. Hepatic ERRγ and SREBP-1c expression was increased by alcohol-mediated activation of CB₁ receptor signaling. Deletion and mutation analyses of the Srebp-1c gene promoter showed that ERRγ directly regulates Srebp-1c gene transcription via binding to an ERR-response element. Overexpression of ERRγ significantly induced SREBP-1c expression and fat accumulation in liver of mice, which were blocked in Srebp-1c-knockout hepatocytes. Conversely, liver-specific ablation of ERRγ gene expression attenuated alcohol-mediated induction of SREBP-1c expression. Finally, an ERRγ inverse agonist, GSK5182, significantly ameliorates fatty liver disease in chronically alcohol-fed mice through inhibition of SREBP-1c-mediated fat accumulation. ERRγ mediates alcohol-induced hepatic lipogenesis by upregulating SREBP-1c expression, which can be blunted by the inverse agonist for ERRγ, which may be an attractive therapeutic strategy for the treatment of alcoholic fatty liver disease in human.

Parkin deficiency prevents chronic ethanol-induced hepatic lipid accumulation through β-catenin accumulation

Background

Alcohol abuse and alcoholism lead to alcohol liver disease such as alcoholic fatty liver. Parkin is a component of the multiprotein E3 ubiquitin ligase complex and is associated with hepatic lipid accumulation. However, the role of parkin in ethanol-induced liver disease has not been reported. Here, we tested the effect of parkin on ethanol-induced fatty liver in parkin knockout (KO) mice with chronic ethanol feeding.

Methods

Male wild type (WT) and parkin KO mice (10–12 weeks old, n = 10) were fed on a Lieber-DeCarli diet containing 6.6% ethanol for 10 days. Liver histological, biochemical, and gene-expression studies were performed.

Results

Parkin KO mice exhibited lower hepatosteatosis after ethanol consumption. Because several studies reported that β-catenin is a critical factor in ethanol metabolism and protects against alcohol-induced hepatosteatosis, we investigated whether parkin changes β-catenin accumulation in the liver of ethanol-fed mice. Our results show that β-catenin was greatly accumulated in the livers of ethanol-fed parkin KO mice compared to ethanol-fed WT mice, and that parkin binds to β-catenin and promotes its degradation it by ubiquitination. Moreover, the β-catenin inhibitor IWR-1 abrogated the attenuation of ethanol-induced hepatic lipid accumulation by parkin deficiency in the livers of parkin KO mice and parkin siRNA-transfected human hepatic cell line.

Conclusions

Parkin deficiency prevents ethanol-induced hepatic lipid accumulation through promotion of β-catenin signaling by failure of β-catenin degradation.

Electronic supplementary material

The online version of this article (10.1186/s12964-019-0424-5) contains supplementary material, which is available to authorized users.

[Protective effects of N-acetyl-L-cysteine against binge drinking-induced fatty liver in mice]

Objective: To investigate the roles of N-acetyl-L-cysteine (NAC) against binge drinking-induced fatty liver in mice. Methods: SPF male C57BL/6 mice were randomly divided into 3 groups, i.e. control group, model group, and NAC/ethanol group (n=10). Mice in model and NAC/ethanol groups were exposed to 3 doses of ethanol (6 g/kg bw) to induced fatty liver, while mice in control group received equal volume and equal energy of maltodextrin solution. NAC was administered to mice at 1 h before ethanol exposure (100 mg/kg bw, i.p.). The mice were sacrificed at 6 h after the last ethanol exposure. The liver and epididymal adipose tissues were collected. Histopathological examination and biochemical assay kit were used to evaluate the fat accumulation, while Western-blot was performed to detect the protein levels of some key factors involved in fat metabolism in liver and adipose tissues. Results: Compored with control group mice, the liver index and liver weight were significantly increased compared with model group, the liver index and TG level in NAC/ethanol group mice were all significantly decreased (P<0.05). Histological examination showed NAC effectively suppressed binge drinking-induced fat accumulation in mice liver. In addition, NAC had no significant effects on the protein levels of peroxisome proliferator-activated receptor-α (PPAR-α), Acy-CoA oxidase (ACOX), sterol regulatory element binding protein 1 c (SREBP-1c) and fatty acid synthase (FAS). Furthermore, the protein levels of hormone sensitive lipase (HSL) did not significantly differ among 3 groups, whereas NAC prevented binge drinking-induced increase of HSL phosphorylation at ser563 and ser660. Conclusion: NAC could effectively attenuate binge drinking-induced fatty liver, which might be associated with the inhibition of lipid mobilization by suppressing the phosphorylation of HSL.

Roles of extrahepatic lipolysis and the disturbance of hepatic fatty acid metabolism in TNF-α -induced hepatic steatosis

Our previous study showed that both Kupffer cell eliminator (GdCl₃) and tumor necrosis factor α (TNF-α) receptor antagonist (etanercept) could partially attenuate binge drinking-induced liver steatosis. Herein, we extended the study by directly investigating the roles of TNF-α on the hepatic fat levels in mice and in HepG2 cells, and explored the underlying mechanisms. SPF male ICR mice were exposed to TNF-α (0.166 mg/kg body weight) with or without phenylisopropyl adenosine (PIA, an anti-lipolytic drug) for 1.5, 3, 6, and 24 h. We found that TNF-α treatment resulted in hepatic triglyceride (TG) elevation at 6 h time point, which was blocked by PIA. TNF-α led to the activation of extrahepatic lipolysis demonstrated by the increase of serum free fatty acid (FFA) level, and the increased protein levels of adipose triglyceride lipase (ATGL) and phosphorylated hormone-sensitive lipase (HSL) in mice epididymal adipose tissues, but had no significant effects on the protein levels of sterol regulatory element binding protein 1c (SREBP-1c) and peroxisomal proliferator activation receptor α (PPAR-α) in mice liver. The in vitro study showed TNF-α treatment could not result in elevation of TG in HepG2 cells, although it indeed brought about a slight activation of SREBP-1c. These results support the hypothesis that TNF-α might make a small contribution to ethanol-induced fatty liver by stimulating extrahepatic lipolysis.

Both alcoholic and non-alcoholic steatohepatitis association with cardiovascular risk and liver fibrosis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of liver disease worldwide. Mortality in NAFLD is mainly related to cardiovascular disease (CVD) and cancer. NAFLD and its association with both CVD and liver disease risk have been well evaluated, but the association of NAFLD with alcohol, known as "both alcoholic and non-alcoholic steatohepatitis" (BASH), remains uncertain. The objective of this study was to assess the influence of alcohol and obesity in the development of liver and cardiovascular disease risk.

METHODS

This was a case-control study that included patients from a regular check-up. Alcohol consumption was evaluated with MAST, AUDIT, and CAGE. Cardiovascular risk was evaluated using the Framingham score, and liver fibrosis was evaluated with APRI and NAFLD score. Patients were classified in five groups: healthy patients, steatosis with obesity, steatosis with alcoholism, BASH, and idiopathic steatosis.

RESULTS

A total of 414 patients were included. The BASH group represented 16% of patients, and showed a greater proportion of patients with high cardiovascular risk with 17% (p = 0.001), and liver fibrosis with 9%, according to the APRI score (p = 0.10). A multivariate logistic regression showed that alcohol consumption >140 g/week (OR 2.546, 95% CI 1.11-5.81, p = 0.003) and BMI >25 kg/m² (OR 12.64, 95% CI 1.66 96.20, p = 0.001) were related to high cardiovascular risk. Liver fibrosis according to APRI was only related to alcohol consumption >140 g/week (OR 2.74, 95% CI 1-7.48, p = 0.03).

CONCLUSIONS

BASH remains an area not well explored, and of great implication given the increasing number of patients affected. We observed an additive effect of both etiologies in the development of high cardiovascular and liver disease risk.

Alcohol-Induced Hepatic Steatosis: A Comparative Study to Identify Possible Indicator(s) of Alcoholic Fatty Liver Disease

Background

Fatty liver is an early sign of both nonalcoholic and alcoholic fatty liver diseases. Ethanol feeding using a Lieber-DeCarli liquid diet (LD) model which contains 35% fat to rats or mice is a well-established model for alcoholic fatty liver. However, LD diet alone can also induce fatty liver and its differential metabolic profile may be able to differentiate steatosis induced by LD versus LD plus ethanol.

Purpose

We investigated the lipidomic differences in the livers of Sprague-Dawley (SD) rats fed a pellet diet (PD), LD and liquid ethanol diet (LED) for six weeks.

Study Design

Male Sprague Dawley rats were fed with nonalcoholic diets PD, LD or LED (ethanol in LD) for six weeks. Lipids were extracted and analyzed by nuclear magnetic resonance (NMR)- based metabolomics. The NMR data obtained was analyzed by multivariate Principal Component Analysis (PCA) and Spotfire DecisionSite 9.0 software to compare PD versus LD and LD versus LED groups.

Results

PCA of the NMR spectral data of livers of both comparisons showed a clear separation of PD from LD group and LD from LED group indicating differences in lipid profiles which corresponded with changes in total lipid weights. LD showed increases for cholesterol, esterified cholesterol, cholesterol acetate and triglycerides with decreases for fatty acyl chain, diallylic and allylic protons, while the LED showed increases in esterified cholesterol, cholesterol acetate, fatty acid methyl esters, allylic protons and some triglyceride protons with decreases in free cholesterol and phosphatidylcholine (PC).

Conclusion

Our data suggest that altered lipid signature or PC levels could be an indicator to differentiate between nonalcoholic versus alcoholic fatty liver.

Relationship between plasma FGF21 level and insulin resistance in patients with alcoholic fatty liver and type 2 diabetes mellitus

AIM

To investigate the relationship between plasma levels of basic fibroblast growth factor 21 (FGF21) and insulin resistance in patients with alcoholic fatty liver (AFL) and type 2 diabetes mellitus (T2DM).

METHODS

Forty-seven patients with simple AFL (group A), 41 with AFL with T2DM (group B), and 40 healthy volunteers (control group) were enrolled in this study. Body mass index (BMI), blood lipid, blood glucose, plasma FGF21 level and insulin resistance parameters were compared among the three groups.

RESULTS

BMI and levels of total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), and free fatty acids (FFAs) in groups A and B were significantly different from those in the control group (P < 0.05), although there was no statistical significance between groups A and B (P > 0.05). The levels of plasma FGF21, fasting plasma glucose (FPG), fasting insulin (FINS), insulin resistance index (HOMA-IR) and insulin sensitivity index (ISI) in groups A and B were significantly different from those in the control group (P < 0.05), and there was also a significant difference between groups A and B (P < 0.05). Plasma FGF21 was positively correlated with BMI, TG, FFA and HOMA-IR (r = 0.512, 0.843, 0.511, and 0.437, respectively; P < 0.05), and was negatively correlated with HDL and ISI (r = -363 and -418 respectively; P < 0.05).

CONCLUSION

Plasma FGF21 levels in patients with AFL with T2DM are higher than those in patients with AFL alone, and there is a certain relationship between FGF21 levels and insulin resistance, suggesting that FGF21 may be involved in the occurrence and development of T2DM.

Impairment of Akt activity by CYP2E1 mediated oxidative stress is involved in chronic ethanol-induced fatty liver

Protein kinase B (PKB/Akt) plays important roles in the regulation of lipid homeostasis, and impairment of Akt activity has been demonstrated to be involved in the development of non-alcoholic fatty liver disease (NAFLD). Previous studies suggest that cytochrome P4502E1 (CYP2E1) plays causal roles in the pathogenesis of alcoholic fatty liver (AFL). We hypothesized that Akt activity might be impaired due to CYP2E1-induced oxidative stress in chronic ethanol-induced hepatic steatosis. In this study, we found that chronic ethanol-induced hepatic steatosis was accompanied with reduced phosphorylation of Akt at Thr308 in mice liver. Chronic ethanol exposure had no effects on the protein levels of phosphatidylinositol 3 kinase (PI3K) and phosphatase and tensin homologue deleted on chromosome ten (PTEN), and led to a slight decrease of phosphoinositide-dependent protein kinase 1 (PDK-1) protein level. Ethanol exposure resulted in increased levels of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE)-Akt adducts, which was significantly inhibited by chlormethiazole (CMZ), an efficient CYP2E1 inhibitor. Interestingly, N-acetyl-L-cysteine (NAC) significantly attenuated chronic ethanol-induced hepatic fat accumulation and the decline of Akt phosphorylation at Thr308. In the in vitro studies, Akt phosphorylation was suppressed in CYP2E1-expressing HepG2 (CYP2E1-HepG2) cells compared with the negative control HepG2 (NC-HepG2) cells, and 4-HNE treatment led to significant decrease of Akt phosphorylation at Thr308 in wild type HepG2 cells. Lastly, pharmacological activation of Akt by insulin-like growth factor-1 (IGF-1) significantly alleviated chronic ethanol-induced fatty liver in mice. Collectively, these results indicate that CYP2E1-induced oxidative stress may be responsible for ethanol-induced suppression of Akt phosphorylation and pharmacological modulation of Akt in liver may be an effective strategy for the treatment of ethanol-induced fatty liver.

Ethanol-induced steatosis involves impairment of lipophagy, associated with reduced Dynamin2 activity

BACKGROUND

Lipid droplets (LDs), the organelles central to alcoholic steatosis, are broken down by lipophagy, a specialized form of autophagy. Here, we hypothesize that ethanol administration retards lipophagy by down-regulating Dynamin 2 (Dyn2), a protein that facilitates lysosome re-formation, contributing to hepatocellular steatosis.

METHODS

Primary hepatocytes were isolated from male Wistar rats fed Lieber-DeCarli control or EtOH liquid diets for 6-8 wk. Hepatocytes were incubated in complete medium (fed) or nutrient-free medium (fasting) with or without the Dyn2 inhibitor Dynasore or the Src inhibitor SU6656. Phosphorylated (active) forms of Src and Dyn2, and markers of autophagy were quantified by Western Blot. Co-localization of LDs-with autophagic machinery was determined by confocal microscopy.

RESULTS

In hepatocytes from pair-fed rats, LD breakdown was accelerated during fasting, as judged by smaller LDs and lower TG content when compared to hepatocytes in complete media. Fasting-induced TG loss in control hepatocytes was significantly blocked by either SU6656 or Dynasore. Compared to controls, hepatocytes from EtOH-fed rats had 66% and 40% lower content of pSrc and pDyn2, respectively, coupled with lower rate of fasting-induced TG loss. This slower rate of fasting-induced TG loss was blocked in cells co-incubated with Dynasore. Microscopic examination of EtOH-fed rat hepatocytes revealed increased co-localization of the autophagosome marker LC3 on LDs with a concomitant decrease in lysosome marker LAMP1. Whole livers and LD fractions of EtOH-fed rats exhibited simultaneous increase in LC3II and p62 over that of controls, indicating a block in lipophagy.

CONCLUSION

Chronic ethanol administration slowed the rate of hepatocyte lipophagy, owing in part to lower levels of phosphorylated Src kinase available to activate its substrate, Dyn2, thereby causing depletion of lysosomes for LD breakdown.

Curcumin improves alcoholic fatty liver by inhibiting fatty acid biosynthesis

Alcoholic fatty liver is a threat to human health. It has been long known that abstinence from alcohol is the most effective therapy, other effective therapies are not available for the treatment in humans. Curcumin has a great potential for anti-oxidation and anti-inflammation, but the effect on metabolic reconstruction remains little known. Here we performed metabolomic analysis by gas chromatography/mass spectrometry and explored ethanol pathogenic insight as well as curcumin action pattern. We identified seventy-one metabolites in mouse liver. Carbohydrates and lipids were characteristic categories. Pathway analysis results revealed that ethanol-induced pathways including biosynthesis of unsaturated fatty acids, fatty acid biosynthesis and pentose and glucuronate interconversions were suppressed by curcumin. Additionally, ethanol enhanced galactose metabolism and pentose phosphate pathway. Glyoxylate and dicarboxylate metabolism and pyruvate metabolism were inhibited in mice fed ethanol diet plus curcumin. Stearic acid, oleic acid and linoleic acid were disease biomarkers and therapical biomarkers. These results reflect the landscape of hepatic metabolism regulation. Our findings illustrate ethanol pathological pathway and metabolic mechanism of curcumin therapy.

Chronic exposure to ethanol causes steatosis and inflammation in zebrafish liver

AIM

To evaluate the effects of chronic exposure to ethanol in the liver and the expression of inflammatory genes in zebrafish.

METHODS

Zebrafish (n = 104), wild type, adult, male and female, were divided into two groups: Control and ethanol (0.05 v/v). The ethanol was directly added into water; tanks water were changed every two days and the ethanol replaced. The animals were fed twice a day with fish food until satiety. After two and four weeks of trial, livers were dissected, histological analysis (hematoxilin-eosin and Oil Red staining) and gene expression assessment of adiponectin, adiponectin receptor 2 (adipor2), sirtuin-1 (sirt-1), tumor necrosis factor-alpha (tnf-a), interleukin-1b (il-1b) and interleukin-10 (il-10) were performed. Ultrastructural evaluations were conducted at fourth week.

RESULTS

Exposing zebrafish to 0.5% ethanol developed intense liver steatosis after four weeks, as demonstrated by oil red staining. In ethanol-treated animals, the main ultrastructural changes were related to cytoplasmic lipid particles and droplets, increased number of rough endoplasmic reticulum cisterns and glycogen particles. Between two and four weeks, hepatic mRNA expression of il-1b, sirt-1 and adipor2 were upregulated, indicating that ethanol triggered signaling molecules which are key elements in both hepatic inflammatory and protective responses. Adiponectin was not detected in the liver of animals exposed and not exposed to ethanol, and il-10 did not show significant difference.

CONCLUSION

Data suggest that inflammatory signaling and ultrastructural alterations play a significant role during hepatic steatosis in zebrafish chronically exposed to ethanol.

Alcoholic fatty liver is enhanced in CYP2A5 knockout mice: The role of the PPARα-FGF21 axis

BACKGROUND & AIMS

Cytochrome P450 2A5 (CYP2A5) is induced by ethanol, and the ethanol induction of CYP2A5 is regulated by nuclear factor-erythroid 2-related factor 2 (NRF2). Cyp2a5 knockout (Cyp2a5^-/-) mice develop more severe alcoholic fatty liver than Cyp2a5^+/+ mice. Fibroblast growth factor 21 (FGF21), a PPARα-regulated liver hormone, is involved in hepatic lipid metabolism. Alcoholic and non-alcoholic fatty liver are enhanced in Pparα knockout (Pparα^-/-) mice. This study investigates the relationship between the PPARα-FGF21 axis and the enhanced alcoholic fatty liver in Cyp2a5^-/- mice.

METHODS

Mice were fed the Lieber-Decarli ethanol diet to induce alcoholic fatty liver.

RESULTS

More severe alcoholic fatty liver disease was developed in Cyp2a5^-/- mice than in Cyp2a5^+/+ mice. Basal FGF21 levels were higher in Cyp2a5^-/- mice than in Cyp2a5^+/+ mice, but ethanol did not further increase the elevated FGF21 levels in Cyp2a5^-/- mice while FGF21 was induced by ethanol in Cyp2a5^+/+ mice. Basal levels of serum FGF21 were lower in Pparα^-/- mice than in Pparα^+/+ mice; ethanol induced FGF21 in Pparα^+/+ mice but not in Pparα^-/- mice, whereas ethanol induced hypertriglyceridemia in Pparα^-/- mice but not in Pparα^+/+ mice. Administration of recombinant FGF21 normalized serum FGF21 and triglyceride in Pparα^-/- mice. Alcoholic fatty liver was enhanced in liver-specific Fgf21 knockout mice. Pparα and Cyp2a5 double knockout (Pparα^-/-/Cyp2a5^-/-) mice developed more severe alcoholic fatty liver than Pparα^+/+/Cyp2a5^-/- mice.

CONCLUSIONS

These results suggest that CYP2A5 protects against the development of alcoholic fatty liver disease, and the PPARα-FGF21 axis contributes to the protective effects of CYP2A5 on alcoholic fatty liver disease.

Presence of alcoholic steatohepatitis, but no selective histological feature, indicates an increased risk of cirrhosis and premature death

OBJECTIVE

The prognostic impact of early stages of histologically confirmed alcoholic liver disease is uncertain. Our aim was to determine the risk of cirrhosis and premature death, and identify prognostic markers, in patients with biopsy-proven alcoholic steatohepatitis - and to compare prognosis in patients with alcoholic pure fatty liver and the general population.

MATERIAL AND METHODS

Patients with biopsy-proven alcoholic fatty liver disease diagnosed during 1976-1987 were identified. Data were collected from medical records, the Danish National Patient Registry and the Registry of Causes of Death. All biopsies were re-examined and morphological findings assessed. A reference cohort matched for age and gender was created. Cox proportional hazard models adjusted for age and gender were used to analyse differences in mortality and cirrhosis development, as well as the prognostic impact of histological and biochemical parameters.

RESULTS

Two hundred and twenty-five patients with fatty liver and 111 with steatohepatitis were followed for median 13 and 9.7 years, respectively. There was a significantly higher risk of developing cirrhosis amongst patients with steatohepatitis compared to both patients with fatty liver (p < 0.001) and the reference cohort (p < 0.001). Mortality was significantly higher in patients with steatohepatitis compared to patients with fatty liver (p = 0.046) and the general population (p < 0.001). No histological or biochemical parameters with prognostic significance for mortality were identified.

CONCLUSION

Presence of steatohepatitis indicates an increased risk of cirrhosis and premature death. However, none of the histological parameters defining steatohepatitis can independently identify patients at risk for premature death.

Ethnicity matters: A Systematic Review and Meta-Analysis of the Non-Linear Relationship Between Alcohol Consumption and Prevalence and Incidence of Hepatic Steatosis

BACKGROUND

Fatty liver (hepatic steatosis) is one of the most common diseases globally, with increasing prevalence. The role of alcohol consumption in the development of hepatic steatosis has not been systematically examined.

METHODS

We searched Medline, Embase, and ProQuest Dissertations & Theses Global for original data on the relationship between alcohol consumption and hepatic steatosis measured by non-invasive imagery, excluding studies conducted in participants <18years, or subgroups related to viral and drug-induced liver disease. We identified 18 articles reporting adjusted data (Japan=11, other high-income countries=7). Random-effect categorical meta-analyses (<20g/day pure alcohol consumption vs non-drinkers) and dose-response meta-analyses for the whole range of alcohol consumption were conducted.

RESULTS

In total, 99,370 participants and 25,662 cases of hepatic steatosis were included. In Japan, low alcohol consumption was consistently associated with substantially reduced incidence and prevalence of hepatic steatosis compared to non-drinkers (RR for <20g pure alcohol/day=0.75, 95% CI: 0.71-0.79, I(2)=0%). No overall association was found in other countries (RR=1.05, 95% CI: 0.86-1.30, I(2)=84%). Dose-response analyses in Japan (up to 80g/day) showed an inverse relationship in men and a J-shape in women.

CONCLUSIONS

Alcohol consumption showed a complex association with hepatic steatosis with substantial differences by ethnicity and sex. Low alcohol consumption was beneficial in Japan with good epidemiological evidence, whereas there was no association in other countries. However, heterogeneity was large in countries other than Japan. More and higher quality research in diverse ethnic populations is needed to further clarify this relationship.

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.

Impairment of autophagosome-lysosome fusion contributes to chronic ethanol-induced liver injury

The pathogenic mechanism underlying alcoholic fatty liver (AFL) is not clear. Autophagy is a self-digestion process that is critical for the maintenance of cellular homeostasis and regulation of lipid metabolism. We investigated the role of autophagy and autophagic flux in hepatic injury induced by chronic ethanol feeding in mice. C57BL/6 mice were fed a Lieber-DeCarli ethanol diet (ED) to induce AFL or an isocaloric control diet for 6 weeks. Chloroquine (CQ, 10 mg/kg, intra-peritoneally [i.p.]) or rapamycin (Rapa, 5 mg/kg, i.p.) were administered during the last 2 weeks of the experimental period. Chronic ethanol feeding induced AFL with focal necrosis associated with increased levels of hepatic triglyceride. This phenomenon was aggravated by CQ, an inhibitor of autophagy, and attenuated by Rapa, an inducer of autophagy. Expression of microtubule-associated protein 1 light chain 3 (LC3)-II and sequestosome1/p62 significantly increased in the ED group. Moreover, accumulation of autophagosomes was observed by transmission electron microscopy in chronic ethanol-treated mice. Chronic ethanol consumption decreased protein expression of LC3 lipidation-related proteins Atg3 and Atg7, and the lysosomal proteins lysosome-associated membrane protein-2 and Rab7, and increased the protein expression of calpain 1 and phosphorylated mammalian target of rapamycin. Taken together, these findings suggest that chronic ethanol consumption leads to impairment of autophagic flux, which contributes to ethanol-induced liver injury.

Expression of 8-OHdG and TBARS in alcoholic fatty liver in rats: Implications for therapeutic effects of vitamin E

AIM: To explore the role of oxidative stress (OS) and lipid peroxidation (LPO) in alcoholic fatty liver (AFL) in rats and to investigate the effect of vitamin E (V_E) on AFL.

METHODS: Forty-five Wistar rats were randomly divided into three groups: a control group (n = 15), an ethanol group (ET, n= 15), and an ET + V_E group (n = 15). The control group was given distilled water by gavage once a day for 8 wk. The ET group was given ET and fish oil by gavage. The ET + V_E group was given additional V_E compared with the ET group. Triglyceride (TG) in the liver was measured by colorimetric method. The contents of 8-hydroxy-deoxyguanosine (8-OHdG) and thiobarbituric acid reactive substances (TBARS) in the liver were measured by enzyme linked immunosorbent assay (ELISA).

RESULTS: The ET group had a significant increase in TG compared with the control group (0.72 ± 0.09 vs 0.28 ± 0.07, P < 0.01). After V_E intervention, TG in the liver decreased. 8-OHdG (1.45 ± 0.17 vs 0.52 ± 0.21, P < 0.01) and TBARS (65.2 ± 9.7 vs 51.2 ± 12.9, P < 0.01) increased significantly in the ET group compared with the control group. 8-OHdG and TBARS decreased significantly in the ET + V_E group compared with the ET group.

CONCLUSION: TG deposits obviously in the liver of AFL rats. OS and LPO play an important role in the pathogenesis of AFL. V_E as an antioxidant can ameliorate AFL induced injury.

Role of Kupffer cells in ischemic injury in alcoholic fatty liver

BACKGROUND

This study was designed to evaluate the role of Kupffer cells (KCs) in hepatic drug metabolizing dysfunction after hepatic ischemia-reperfusion (IR) in alcoholic fatty liver.

MATERIALS AND METHODS

Rats were fed the Lieber-DeCarli diet for 5 wk to develop alcoholic fatty liver, then were subjected to 90 min of hepatic ischemia and 5 h of reperfusion. For ablation of KCs, rats were pretreated with gadolinium chloride (GdCl3) 48 and 24 h before the IR procedure.

RESULTS

After the IR procedure, ethanol diet (ED)-fed rats had higher serum aminotransferase activity compared with the control diet-fed rats. These changes were attenuated by GdCl3. The ED-fed rats exhibited increased hepatic microsomal total cytochrome P450 (CYP) content and nicotinamide adenine dinucleotide phosphate-CYP reductase and CYP1A1, 1A2, 2B1, and 2E1 isozyme activity. After hepatic IR, these increases were reduced to lower levels than observed in the sham group, except CYP2E1 activity. Increases in CYP2E1 activity and its expression were augmented after hepatic IR in ED-fed animals, but were attenuated by GdCl3. Finally, toll-like receptor 4 and myeloid differentiation primary response gene 88 protein expression, nuclear translocation of nuclear factor-κB and activator protein 1, and levels of proinflammatory mediators were further increased in ED-fed animals compared with control diet-fed animals after IR. These increases were attenuated by GdCl3.

CONCLUSIONS

We suggest that KCs contribute to hepatic drug metabolizing dysfunction during hepatic IR in alcoholic fatty liver via the toll-like receptors 4-mediated inflammatory response.

Alcoholic fatty liver disease elevates estimated coronary heart disease risk to levels comparable with those of nonalcoholic fatty liver disease in the Korean population: a cross-sectional study

Background/Aims

A close relationship has been established between nonalcoholic fatty liver disease (NAFLD) and an elevated risk of coronary heart disease (CHD), but little is known about the association between alcoholic fatty liver disease (AFLD) and CHD risk. The aim of this study was to determine whether AFLD is associated with elevated CHD risk.

Methods

We retrospectively enrolled 10,710 subjects out of 11,469 individuals who visited the Konkuk University Health Care Center for a routine health checkup in 2010. AFLD was diagnosed made when the usual amount of alcohol consumption exceeded 210 g/week in males and 140 g/week in females for the previous 2 years and when hepatic steatosis was detected by liver ultrasonography. The 10-year risk for CHD was estimated using the Framingham Risk Score.

Results

Hepatic steatosis was diagnosed in 4,142 of the 10,710 individuals (38.7%); the remainder (i.e., n=6,568) became the control group. The 4,142 individuals with hepatic steatosis were divided into two groups: NAFLD (n=2,953) and AFLD (n=1,189). The risk of CHD was higher in AFLD (6.72±0.12) than in the control group (5.50±0.04, P<0.001), and comparable to that in NAFLD (7.32±0.07, P=0.02).

Conclusions

Individuals with AFLD have an elevated 10-year risk of CHD that is comparable to those with NAFLD. Therefore, AFLD should be considered a significant risk for future CHD, and preventive measures should be considered earlier.

Activation of farnesoid X receptor attenuates hepatic injury in a murine model of alcoholic liver disease

Alcoholic liver disease (ALD) is a common cause of advanced liver disease, and considered as a major risk factor of morbidity and mortality worldwide. Hepatic cholestasis is a pathophysiological feature observed in all stages of ALD. The farnesoid X receptor (FXR) is a member of the nuclear hormone receptor superfamily, and plays an essential role in the regulation of bile acid, lipid and glucose homeostasis. However, the role of FXR in the pathogenesis and progression of ALD remains largely unknown. Mice were fed Lieber-DeCarli ethanol diet or an isocaloric control diet. We used a specific agonist of FXR WAY-362450 to study the effect of pharmacological activation of FXR in alcoholic liver disease. In this study, we demonstrated that FXR activity was impaired by chronic ethanol ingestion in a murine model of ALD. Activation of FXR by specific agonist WAY-362450 protected mice from the development of ALD. We also found that WAY-362450 treatment rescued FXR activity, suppressed ethanol-induced Cyp2e1 up-regulation and attenuated oxidative stress in liver. Our results highlight a key role of FXR in the modulation of ALD development, and propose specific FXR agonists for the treatment of ALD patients.

D-xylose protects against alcohol-induced steatosis in HepG2 cells

AIM: To investigate the protective effect of D-xylose against alcohol-induced hepatic cell steatosis.

METHODS: HepG2 cells were divided into three groups: normal control group, alcohol-injured group, and D-xylose group. Steatosis was induced with alcohol in cells in the alcohol-injured group and D-xylose group. The D-xylose group was treated with different concentrations of D-xylose. After treatment, cell apoptosis and growth were observed based on morphology, while cell viability was tested by MTT assay. The degree of steatosis in viable cells was evaluated by Oil Red O staining. RT-PCR was employed for testing the changes in PPARγ expression levels.

RESULTS: In the D-xylose groups, hepatic cell survival rate was increased significantly (88.5%, 81.8%, 75.4% vs 44.0%, all P < 0.05) and the degree of steatosis was alleviated (0.63250 ± 0.068172, 0.60400 ± 0042798, 0.95538 ± 0.067853 vs 0.97313 ± 0.063481, all P < 0.05) compared to the alcohol-injured group. The mRNA level of PPARγ was significantly higher in the alcohol-injured group than in the control group; however, D-xylose significantly reduced the degree of steatosis in a concentration-dependent manner.

CONCLUSION: D-xylose can reduce alcohol-induced hepatic cell injury and steatosis possibly by decreasing lipid generation.

Effect of palmitic acid on ethanol-induced fatty degeneration in hepatic cells in vitro

AIM: To determine the effect of different concentrations of palmitic acid on alcohol-induced lipogenesis in L-02 liver cells and to explore mechanisms involved.

METHODS: Cultured L-02 liver cells were divided into three groups: blank control group, alcohol induction group, and palmitic acid intervention group, which were cultured in RPMI 1640 medium containing 10% serum, RPMI 1640 medium containing 10% serum and 6% ethanol, and RPMI 1640 medium containing 10% serum, 6% ethanol and different concentrations of palmitic acid (2.5, 5, 10, 20, 30, and 40 µmol/L), respectively. Cell proliferation was measured by MTT assay. The accumulation of lipid droplets was observed by light inverted microscopy after red oil-O staining. Intracellular triglyceride (TG) level was determined using commercial kits. Western blot was used to detect the levels of nuclear SREBP-1c protein in hepatocytes of each group.

RESULTS: A model of alcohol-induced steatosis was successfully induced in L-02 liver cells by incubation with 0.6% ethanol for 72 h. Compared to the alcohol induction group, palmitic acid at concentrations of 2.5, 5, and 10 µmol/L could not only significantly promote cell proliferation (all P < 0.05) but also significantly reduce the accumulation of lipid droplets and the levels of intracellular TG and nuclear SREBP-1c protein (all P < 0.05), showing concentration-dependent protective effects. However, palmitic acid at concentrations of 20, 30 and 40 µmol/L significantly inhibited cell proliferation (all P < 0.05) and increased the accumulation of lipid droplets and the levels of intracellular TG and nuclear SREBP-1c protein (all P < 0.05), showing harmful effect on alcohol-induced steatosis in L-02 liver cells.

CONCLUSION: Palmitic acid at concentrations <10 µmol/L has protective effects and palmitic acid at concentrations >10 µmol/L has harmful effects on alcohol-induced steatosis in L-02 liver cells. Palmitic acid exerts effects on alcohol-induced steatosis in L-02 liver cells via mechanisms associated with regulating the expression of nuclear SREBP-1c protein in hepatocytes.

Effects of quercetin on the expression of nuclear factor kappaB in alcoholic fatty liver of rats

AIM: To explore the effect and possible mechanism of quercetin on alcoholic fatty liver (AFL) in rats.

METHODS: Forty-eight male wistar rats were randomly divided into four groups: normal control, model, quercetin and naloxone groups. By the end of the fourth week, all rats were weighed, narcotized, sacrificed, and tested for expression levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and tumor necrosis factor-alpha (TNF-α) in plasma. Liver samples were analyzed for common histopathological changes and the expression of nuclear factor kappaB (NF-κB) was measured by immunohistochemical staining.

RESULTS: Levels of AST, ALT, and TNF-α in plasma were markedly lower in the quercetin and naloxone groups than the model group (quercetin, 150.7 ± 23.6 U/L, 57.4 ± 8.4 U/L, 0.83 ± 0.27 µg/L; naloxone, 148.3 ± 21.4 U/L, 55.2 ± 7.3 U/L, 0.85 ± 0.34 µg/L vs 205.0 ± 31.5 U/L, 70.5 ± 9.2 U/L, 4.08 ± 1.23 µg/L; P < 0.05), but were higher in the quercetin and naloxone groups than in the normal contrast group (127.6 ± 17.8 U/L, 47.9 ± 7.1 U/L, 0.22 ± 0.10 µg/L; P < 0.05). Compared with the model group, the degree of liver fatty degeneration in the quercetin and naloxone groups was slight, and the expression level of NF-κB in liver tissue was clearly lower in the quercetin group (60.27/HP vs 28.49/HP, P < 0.05).

CONCLUSION: Quercetin may have a role in preventing alcoholic fatty liver by inhibiting expression of NF-κB and TNF-α.

Experimental study of osthole on treatment of hyperlipidemic and alcoholic fatty liver in animals

AIM: To evaluate the effects of osthole on fatty liver, and investigate the possible mechanism.

METHODS: A quail model with hyperlipidemic fatty liver and rat model with alcoholic fatty liver were set up by feeding high fat diet and alcohol, respectively. These experimental animals were then treated with osthole 5-20 mg/kg for 6 wk, respectively. Whereafter, the lipid in serum and hepatic tissue, and coefficient of hepatic weight were measured.

RESULTS: After treatment with osthole the levels of serum total cholesterol (TC), triglyceride (TG), lower density lipoprotein-cholesterol (LDL-C), coefficient of hepatic weight, and the hepatic tissue contents of TC and TG were significantly decreased. The activity of superoxide dismutase (SOD) in liver was improved. In alcohol-induced fatty liver rats, the level of malondialdehyde (MDA) in liver was decreased. In high fat-induced fatty liver quails, glutathione peroxidase (GSH-PX) in liver was significantly improved. The histological evaluation of liver specimens demonstrated that the osthole dramatically decreased lipid accumulation.

CONCLUSION: These results suggested that osthole had therapeutic effects on both alcohol and high fat-induced fatty liver. The mechanism might be associated with its antioxidation.