Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0015695 (fatty liver)
 13,941 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Emerging attention has been paid to metabolic syndrome, which comprises several metabolic disorders including visceral obesity, diabetes mellitus, dyslipidemia, and hypertension. Whether the severity of each disease is mild to moderate, the comorbidity of these metabolic disorders has a serious impact on the development of atherosclerosis. Nonalcoholic fatty liver disease (NAFLD) is the major hepatic disorder in patients with metabolic syndrome, and indeed it is the most common cause of abnormal liver function tests in the working population in industrialized countries. In recent years, it has become recognized that NAFLD is no longer just a trivial disease, and a rather considerable proportion of the patients develop liver cirrhosis. Furthermore, chronic infection of hepatitis C virus also develops a pathological feature of steatohepatitis, and extended hepatic steatosis has a serious impact not only on the progression of hepatic fibrosis but also on the antiviral efficacy of interferon therapy. Emerging lines of studies indicated that insulin resistance, abnormal lipid metabolism, and dysregulation of cytokines/adipokines (e.g., tumor necrosis factor-alpha, adiponectin, and leptin) are profoundly involved in the pathogenesis of NAFLD. This review aims to integrate the reported evidence and to provide the current point of view for comprehensive understanding of the pathophysiology of steatohepatitis.
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PMID:Liver diseases and metabolic syndrome. 1864 37

Worldwide, one of the most prevalent forms of chronic disease is alcoholic fatty liver, which may progress to more severe forms of liver injury including steatohepatitis, fibrosis, and cirrhosis. The molecular mechanisms by which ethanol consumption causes accumulation of hepatic lipid are multiple and complex. Chronic ethanol exposure is thought to cause enhanced hepatic lipogenesis and impaired fatty acid oxidation by inhibiting key hepatic transcriptional regulators such as AMP-activated kinase (AMPK), sirtuin 1 (SIRT1), PPAR-gamma coactivator alpha (PGC-1alpha), peroxisome proliferator-activated receptor alpha (PPARalpha), and sterol regulatory element-binding protein 1 (SREBP-1). Adiponectin is an adipose-derived hormone with a variety of beneficial biological functions. Increasing evidence suggests that altered adiponectin production in adipose tissue and impaired expression of hepatic adiponectin receptors (AdipoRs) are associated with the development of alcoholic liver steatosis in several rodent models. More importantly, studies have demonstrated a protective role of adiponectin against alcoholic liver steatosis. The hepato-protective effect of adiponectin is largely mediated by the coordination of multiple signaling pathways in the liver, leading to enhanced fat oxidation, reduced lipid synthesis and prevention of hepatic steatosis. This review begins with an assessment of the current understanding of the role of adiponectin and its receptors in the regulation of lipid homeostasis in liver, with emphasis on their relationship to the development of alcoholic liver steatosis. Following sections will review hepatic signaling molecules involved in the protective actions of adiponectin against alcoholic fatty liver and summarize the current knowledge of regulatory mechanisms of adiponectin expression and secretion in response to chronic ethanol exposure. We will conclude with a discussion of potential strategies for treating human alcoholic fatty liver disease (AFLD), including nutritional and pharmacological modulation of adiponectin and its receptors.
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PMID:Adiponectin and alcoholic fatty liver disease. 1870 50

Nonalcoholic steatohepatitis (NASH) is the hepatic manifestation of the metabolic syndrome. Currently, there is no established therapy for NASH. The aim of the present study was to evaluate the efficacy of atorvastatin in the treatment of NASH associated with hyperlipidemia. This prospective study included 31 patients with biopsy-proven NASH with hyperlipidemia. Body mass index, serum lipids, liver function tests, fibrosis markers, and adipocytokines (adiponectin, leptin, tumor necrosis factor-alpha) were measured periodically during an open-label study of atorvastatin (10 mg daily) for 24 months. Standard weight-loss counseling was continued during the treatment period. Oral glucose tolerance test and liver density assessed by computerized tomography were performed before and after treatment. Follow-up liver biopsy was performed in 17 patients. All 31 patients had high cholesterol levels at baseline, and 20 also presented high triglyceride levels. The body mass index and serum glucose levels did not change during the treatment. After treatment, 23 patients (74.2%) presented normal transaminase levels. Adiponectin levels were significantly increased, and the levels of tumor necrosis factor-alpha were significantly decreased. However, leptin levels were not changed significantly. The concentration of long-chain fatty acids was decreased; and significant decreases were observed in C18:2,n-6 (linoleic acid, -21%) and C20:4,n-6 (arachidonic acid, -22%). Liver steatosis and nonalcoholic fatty liver disease activity score were significantly improved, whereas 4 patients had increased fibrosis stage. The NASH-related metabolic parameters improved with therapy, including fibrosis in some patients. However, 4 of 17 patients had progression of fibrosis over the 2-year period, with 3 of them progressing to stage 3. It is unclear whether this divergent response represents sampling error, heterogeneity in the population, or untreated postprandial hyperglyceridemia. Controlled trials are needed to further investigate and resolve this.
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PMID:Efficacy of atorvastatin for the treatment of nonalcoholic steatohepatitis with dyslipidemia. 1901 95

The aim of this study was to determine if orlistat, an inhibitor of fat absorption, combined with caloric restriction in overweight subjects with nonalcoholic steatohepatitis results in weight loss and improved liver histology. Fifty overweight subjects (body mass index = >or=27) with biopsy proven nonalcoholic steatohepatitis were randomized to receive a 1,400 Kcal/day diet plus vitamin E (800 IU) daily with or without orlistat (120 mg three times a day) for 36 weeks. Liver biopsies were repeated at week 36. Twenty-three subjects in the orlistat/diet/vitamin E group and 18 in the diet/vitamin E group completed the study. The mean age was 47 +/- 9.0 (standard deviation) years and mean body mass index was 36.4 +/- 6.3 kg/m(2). Four subjects were diabetic. The orlistat group lost a mean of 8.3% body weight compared to 6.0% in the diet plus vitamin E group (not significant). Both groups also had similarly improved serum aminotransferases, hepatic steatosis, necroinflammation, ballooning, and nonalcoholic fatty liver disease activity scores. Stratified according to weight loss instead of treatment group, a loss of >or=5% body weight (n = 24) compared to <5% body weight (n = 17) correlated with improvement in insulin sensitivity (P = 0.001) and steatosis (P = 0.015). Comparing subjects who lost >or=9% of body weight (n = 16), to those that did not (n = 25), improved insulin sensitivity (P < 0.001), adiponectin (P = 0.03), steatosis (P = 0.005), ballooning (P = 0.04), inflammation (P = 0.045), and nonalcoholic fatty liver disease activity score (P = 0.009) were seen. Increases in adiponectin strongly correlated with improved ballooning and nonalcoholic fatty liver disease activity score (P = 0.03). Orlistat did not enhance weight loss or improve liver enzymes, measures of insulin resistance, and histopathology. However, subjects who lost >or=5% of body weight over 9 months improved insulin resistance and steatosis, and those subjects who lost >or=9% also achieved improved hepatic histologic changes.
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PMID:Orlistat for overweight subjects with nonalcoholic steatohepatitis: A randomized, prospective trial. 1949 25

Subcutaneous and visceral adipose compartments act, not only as fatty acid depots, but also as active endocrine organs that undergo hyperplastic changes and significantly enhance their function in obesity. Akipokines and other proteins secreted by both adipocytes and stromal cells play a central role in peripheral insulin resistance and the metabolic syndrome (MS). Minor alleles of the adipokine genes substantially contribute to MS. The most important consequence of MS is low-level systemic inflammation supported by adipose-specific synthesis of proinflammatory soluble molecules. Proinflammatory signals are secreted into the bloodstream and spread to peripheral tissues that contain their receptors. The signals provided by adipose tissue stimulate the development of secondary complications of MS, including cardiovascular disorders (CVDs) and nonalcoholic fatty liver disease. The review describes the physiological effects of adiponectin, leptin, resistin, visfatin, and apelin and the influence of the minor alleles of the adipokine genes on the development of the secondary complications of MS.
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PMID:[Adipokine genetics: unbalanced protein secretion by human adipose tissue as a cause of the metabolic syndrome]. 1906 31

1. Angiotensin-converting enzyme inhibitors (ACEI) are hypotensive drugs that have been shown to prevent Type 2 diabetes mellitus (T2DM) in high-risk individuals. However, in T2DM, the effects of ACEI on hepatic steatosis are not known. The aim of the present study was to examine the effects of ACEI on changes in liver histology and hepatic mRNA expression of adipokines in rats with T2DM. 2. Thirty-six rats were divided into a normal control group, a T2DM group and a fosinopril-treated group. After six weeks of treatment with 5 mg/kg per day fosinopril, an ACEI, changes in liver histology, serum fasting glucose (FG), insulin, triglyceride (TG), total cholesterol (TC), alanine aminotransferase (ALT), aspartate aminotransferase (AST), tumour necrosis factor (TNF)-alpha, interleukin (IL)-6, adiponectin were evaluated, as was hepatic TNF-alpha, IL-6 and adiponectin receptor-2 (adipoR2) mRNA expression. 3. The degree of hepatic steatosis and inflammation, serum FG, insulin, TG, TC, ALT, TNF-alpha and IL-6 concentrations and hepatic TNF-alpha and IL-6 mRNA expression were significantly higher in rats with T2DM than in normal controls. Serum adiponectin concentrations and hepatic adipoR2 mRNA expression in rats with T2DM were significantly lower than in normal controls. Fosinopril significantly reduced the degree of hepatic steatosis, serum FG, insulin, ALT, TNF-alpha and IL-6 concentrations and hepatic TNF-alpha and IL-6 mRNA expression. Fosinopril significantly increased serum adiponectin concentrations and hepatic adipoR2 mRNA expression. 4. In conclusion, the ACEI improved insulin sensitivity and hepatic steatosis in rats with T2DM by increasing circulating adiponectin and hepatic adipoR2 levels, in addition to reducing pro-inflammatory cytokine levels in the circulation and liver.
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PMID:Angiotensin-converting enzyme inhibitors improve hepatic steatosis by modulating expression of tumour necrosis factor-alpha, interleukin-6 and adiponectin receptor-2 in rats with type 2 diabetes. 1907 62

We aimed at determining which circulating forms of the adipokine adiponectin that increases lipid oxidation in liver and skeletal muscle are related to ectopic fat in these depots in humans. Plasma total-, high-molecular weight (HMW)-, middle-molecular weight (MMW)-, and low-molecular weight (LMW) adiponectin were quantified by an enzyme-linked immunosorbent assay. Their relationships with liver- and intramyocellular fat, measured using (1)H magnetic resonance spectroscopy, were investigated in 54 whites without type 2 diabetes. Liver fat, adjusted for gender, age, and total body fat, was associated only with HMW adiponectin (r = -0.35, P = 0.012), but not with total-, MMW-, or LMW adiponectin. In addition, subjects with fatty liver (liver fat > or =5.56%, n = 15) had significantly lower HMW- (P = 0.04), but not total-, MMW-, or LMW adiponectin levels, compared to controls (n = 39). Similarly, intramyocellular fat correlated only with HMW (r = -0.32, P = 0.039), but not with the other circulating forms of adiponectin. These data indicate that, among circulating forms of adiponectin, HMW is strongly related to ectopic fat, thus possibly representing the form of adiponectin regulating lipid oxidation in liver and skeletal muscle.
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PMID:Adiponectin oligomers and ectopic fat in liver and skeletal muscle in humans. 1916 22

Apolipoprotein D (apoD), a widely expressed lipocalin, has the capacity to transport small hydrophobic molecules. Although it has been proposed that apoD may have multiple tissue-specific, physiological ligands and functions, these have yet to be identified. To gain insight in some of its functions, we generated transgenic mice overexpressing human apoD (H-apoD) under the control of neuron-specific promoters. In Thy-1/apoD and NSE/apoD mice, expression of H-apoD was strong in the nervous system although weakly detected in peripheral organs such as the liver and blood cells. These mice displayed not entirely anticipated metabolic defects. Although they are not obese and have normal lipid concentration in circulation, Thy-1/apoD and NSE/apoD mice are glucose intolerant, insulin resistant, and develop hepatic steatosis. The steatosis and its associated insulin resistance are correlated with impairments in hepatic lipogenesis. However, they are not strongly related with inflammation. This impaired insulin response is not caused by a decrease in circulating leptin or a modulation of adiponectin and resistin levels. These results suggest that variations in the levels and/or sites of apoD expression influence the lipid and glucose metabolism, consolidating apoD as a target for insulin-resistance-related disorders.
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PMID:Human apolipoprotein D overexpression in transgenic mice induces insulin resistance and alters lipid metabolism. 1917 53

Omega-3-polyunsaturated fatty acids (omega-3-PUFAs) have well-documented protective effects that are attributed not only to eicosanoid inhibition but also to the formation of novel biologically active lipid mediators (i.e., resolvins and protectins). In this study, we examined their effects on ob/ob mice, an obesity model of insulin resistance and fatty liver disease. Dietary intake of omega-3-PUFAs had insulin-sensitizing actions in adipose tissue and liver and improved insulin tolerance in obese mice. Genes involved in insulin sensitivity (PPARgamma), glucose transport (GLUT-2/GLUT-4), and insulin receptor signaling (IRS-1/IRS-2) were up-regulated by omega-3-PUFAs. Moreover, omega-3-PUFAs increased adiponectin, an anti-inflammatory and insulin-sensitizing adipokine, and induced AMPK phosphorylation, a fuel-sensing enzyme and a gatekeeper of the energy balance. Concomitantly, hepatic steatosis was alleviated by omega-3-PUFAs. A lipidomic analysis with liquid chromatography/mass spectrometry/mass spectrometry revealed that omega-3-PUFAs inhibited the formation of omega-6-PUFA-derived eicosanoids, while triggering the formation of omega-3-PUFA-derived resolvins and protectins. Moreover, representative members of these lipid mediators, namely resolvin E1 and protectin D1, mimicked the insulin-sensitizing and antisteatotic effects of omega-3-PUFAs and induced adiponectin expression to a similar extent that of rosiglitazone, a member of the thiazolidinedione family of antidiabetic drugs. Taken together, these findings uncover beneficial actions of omega-3-PUFAs and their bioactive lipid autacoids in preventing obesity-induced insulin resistance and hepatic steatosis.
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PMID:Obesity-induced insulin resistance and hepatic steatosis are alleviated by omega-3 fatty acids: a role for resolvins and protectins. 1921 25

Increases in adiposity trigger metabolic and inflammatory changes that interfere with insulin action in peripheral tissues, culminating in beta cell failure and overt diabetes. We found that the cAMP Response Element Binding protein (CREB) is activated in adipose cells under obese conditions, where it promotes insulin resistance by triggering expression of the transcriptional repressor ATF3 and thereby downregulating expression of the adipokine hormone adiponectin as well as the insulin-sensitive glucose transporter 4 (GLUT4). Transgenic mice expressing a dominant-negative CREB transgene in adipocytes displayed increased whole-body insulin sensitivity in the contexts of diet-induced and genetic obesity, and they were protected from the development of hepatic steatosis and adipose tissue inflammation. These results indicate that adipocyte CREB provides an early signal in the progression to type 2 diabetes.
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PMID:Adipocyte CREB promotes insulin resistance in obesity. 1925 72


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