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)

Current knowledge on gamma glutamyl transpeptidase (gammaGTP) was reviewed. This enzyme, which is mainly expresses on the cell surface, is thought to participate in catalyzing glutathione breakdown, resulting in the formation of cystein, a thiol compound exerting antioxidant effects. The most important role of this enzyme in vivo seems to recover cystein from extracellular glutathione to preserve intracellular homeostasis of oxidative stress. Increase in environmental oxidative stress may induce this enzyme via NFkB. However, its excessive induction may contrary raise oxidative stress and cause subsequent organ injuries since cysteinylglycine, an intermediate of the glutathione breakdown, affects the iron metabolism, resulting in the production of free radicals. Recently, there are multiple lines of evidence that the development of hypertension, hyperlipidemia, diabetes mellitus is associated with increased serum gammaGTP levels. The oxidative stress derived from gammaGTP may participate in the development of these morbid conditions and would account for these associations. However, since subjects associated with excessive drinking and overweight, two major factors increasing serum gammaGTP level are usually suffering from hypertension, hyperlipidemia, diabetes mellitus, it is most likely that the associations are attributed to excessive drinking and overweight. We recently demonstrated that level of serum gammaGTP is inversely associated with that of serum adiponectin, a sort of adipocytokines. In that abnormalities of adipocytokines including adiponectin cause hypertension, hyperlipidemia, diabetes mellitus as well as fatty liver that is associated with increased gammaGTP level, the status of adipocytokines may stand behind the associations among these factors in obese subjects. Moreover, we demonstrated that serum gammaGTP level is inversely associated with subjects' statuses of lifestyles evaluated by Breslow's lifestyle index, suggesting that serum gammaGTP activity could be a tool for screening of subjects with unhealthy lifestyles. In that unhealthy lifestyles cause various morbid conditions designated as lifestyle-related diseases that is thought to comprehend metabolic syndrome and/or alcohol-related diseases, such screening and intervention in their correction should be significant to prevent their development. The consensus currently reached is that increased serum gammaGTP activity is associated with increased mortality. In that excessive drinking, obesity, as well as improper lifestyle elevate serum gammaGTP activity meanwhile cause various morbid conditions that make lifespan shorter, the view is not surprising.
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PMID:[Gamma glutamyl transpeptidase (gammaGTP) in the era of metabolic syndrome]. 1766 41

Alcohol-induced fatty liver (steatosis) was believed to result from excessive generation of reducing equivalents from ethanol metabolism, thereby enhancing fat accumulation. Recent findings have revealed a more complex picture in which ethanol oxidation is still required, but specific transcription as well as humoral factors also have important roles. Transcription factors involved include the sterol regulatory element binding protein 1 (SREBP-1) which is activated to induce genes that regulate lipid biosynthesis. Conversely, ethanol consumption causes a general down-regulation of lipid (fatty acid) oxidation, a reflection of inactivation of the peroxisome proliferator-activated receptor-alpha (PPAR-alpha) that regulates genes involved in fatty acid oxidation. A third transcription factor is the early growth response-1 (Egr-1), which is strongly induced prior to the onset of steatosis. The activities of all these factors are governed by that of the principal regulatory enzyme, AMP kinase. Important humoral factors, including adiponectin, and tumor necrosis factor-alpha (TNF-alpha), also regulate alcohol-induced steatosis. Their levels are affected by alcohol consumption and by each other. This review will summarize the actions of these proteins in ethanol-elicited fatty liver. Because steatosis is now regarded as a significant risk factor for advanced liver pathology, an understanding of the molecular mechanisms in its etiology is essential for development of effective therapies.
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PMID:Alcohol-induced steatosis in liver cells. 1785 40

Overweight and obesity among children and adolescents are increasing. Fatty liver disease (FLD) is an emerging problem in this age group. We investigated prevalence of overweight and non-invasive FLD and associated clinical characteristics in a representative population-based sample of 378 children and adolescents aged 12-20 years who were randomly selected from the general population in Leutkirch, Southern Germany. Overweight was defined as having a body mass index above the 90th percentile for the respective age and sex. About 15% of female (29 out of 194) and 12% of male participants (22/182) were overweight. Among females, only one non-overweight individual showed signs of FLD but in more than one third of the overweight males (8/22) signs of FLD were present. Overweight subjects in general had an unfavourable lipid profile and abnormal concentrations of obesity-related hormones such as significantly lower concentrations of adiponectin and increased levels of inflammatory markers including C-reactive protein and fibrinogen. Overweight males with signs of FLD showed even more severe altered metabolic responses compared to those who were overweight without signs of liver injury. FLD was not explained by alcohol consumption or other chronic liver disease. In this sample of children and adolescents representative of the general population a high prevalence of non-alcoholic fatty liver disease (NAFLD) is found in overweight males. These individuals showed the most severe metabolic alterations compared to non-overweight and overweight individuals without NAFLD indicating even higher risk for future overweight and obesity-related diseases such as type 2 diabetes and cardiovascular disease.
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PMID:Prevalence of non-alcoholic fatty liver and characteristics in overweight adolescents in the general population. 1789 81

Retinol binding protein 4 (RBP4) is a protein secreted by adipocytes, and closely associated with insulin resistance. Whereas RBP4 is also mainly expressed in hepatocytes as the principal transport protein for retinol (vitamin A) in the circulation, and its pathophysiological role in liver remain unclear. The aim of this paper was to investigate the association between RBP4 and nonalcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus (T2DM). Serum RBP4 and adiponectin concentrations were measured by radioimmunoassay in 52 diabetic patients who had NAFLD and 50 sex- and age-matched diabetic patients without any clinical features of liver diseases who had normal liver ultrasonic appearance and normal liver function. Serum RBP4 levels were elevated in diabetic patients with NAFLD (32.0+/-8.9 microg/ml vs. 41.3+/-9.8 microg/ml, p<0.001), while adiponectin decreased (17.4+/-9.3 microg/ml vs. 13.8+/-7.0 microg/ml, p=0.032). Male diabetic patients had higher serum RBP4 concentration and lower serum adiponectin concentration than female diabetic patients (38.5+/-9.9 microg/ml vs. 34.0+/-10.7 microg/ml, p=0.031 and 12.7+/-5.7 microg/ml vs. 20.23+/-9.8 microg/ml, p<0.001, respectively). Multiple logistic regression analysis revealed RBP4 and triglyceride as independent association factors for NAFLD, while the association between serum adiponectin and NAFLD was not significant. Increasing concentrations of RBP4 were independently and significantly associated with NAFLD in diabetic patients. In multiple linear regression analysis, alanine aminotransferase, fasting serum insulin and adiponectin were independent factors for serum RBP4 level. The study demonstrates that retinol binding protein 4 might contribute to the pathogenesis of nonalcoholic fatty liver disease.
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PMID:Serum retinol binding protein 4 and nonalcoholic fatty liver disease in patients with type 2 diabetes mellitus. 1790 83

Conjugated linoleic acid (CLA) induces insulin resistance preceded by rapid depletion of the adipokines leptin and adiponectin, increased inflammation, and hepatic steatosis in mice. To determine the role of leptin in CLA-mediated insulin resistance and hepatic steatosis, recombinant leptin was coadministered with dietary CLA in ob/ob mice to control leptin levels and to, in effect, negate the leptin depletion effect of CLA. In a 2 x 2 factorial design, 6 week old male ob/ob mice were fed either a control diet or a diet supplemented with CLA and received daily intraperitoneal injections of either leptin or vehicle for 4 weeks. In the absence of leptin, CLA significantly depleted adiponectin and induced insulin resistance, but it did not increase hepatic triglyceride concentrations or adipose inflammation, marked by interleukin-6 and tumor necrosis factor-alpha mRNA expression. Insulin resistance, however, was accompanied by increased macrophage infiltration (F4/80 mRNA) in adipose tissue. In the presence of leptin, CLA depleted adiponectin but did not induce insulin resistance or macrophage infiltration. Despite this, CLA induced hepatic steatosis. In summary, CLA worsened insulin resistance without evidence of inflammation or hepatic steatosis in mice after 4 weeks. In the presence of leptin, CLA failed to worsen insulin resistance but induced hepatic steatosis in ob/ob mice.
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PMID:Conjugated linoleic acid fails to worsen insulin resistance but induces hepatic steatosis in the presence of leptin in ob/ob mice. 1790 21

The objective of this work was to study the influence of insulin resistance and adipokines on the grade of steatosis in patients with NAFLD (nonalcoholic fatty liver disease) diagnosed by liver biopsy. A sample of 24 NAFLD patients was analyzed in a cross-sectional study. All patients with a two-week weight-stabilization period before recruitment were enrolled. A liver biopsy was realized. Weight, basal glucose, insulin, insulin resistance (HOMA), total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, and adipokines blood levels were measured. A nutritional evaluation (dietary intake, indirect calorimetry, and bioimpedance) was performed. The mean age was 41.6 +/- 8.7 years and the mean body mass index (BMI) 29.4 +/- 4.7. Twelve patients had a low grade of steatosis (grade 1 of the Brunt classification) and 12 patients had a high grade of steatosis (grade 2 or 3). Only HOMA was higher in patients with a high grade of steatosis (1.4 +/- 0.5 vs. 2.8 +/- 1.7 units; P < 0.05). Anthropometric data and dietary intake were similar for both groups. Blood levels of adiponectin were higher in patients with a low grade of steatosis (37.7 +/- 22.5 vs. 24.2 +/- 33 ng mL(-1); P < 0.05). Blood levels of resistin were higher in patients with a high grade of steatosis (2.36 +/- 0.6 vs. 2.8 +/- 0.6 mg mL(-1); P < 0.05), without differences in TNF-alpha or leptin levels. In logistic regression analysis, the HOMA-IR remained in the model, with an odds ratio to develop high grade of steatosis of 7.8 (95% CI: 1.8-75) with each 1 unit of HOMA-IR adjusted by age, sex, BMI, and dietary intake. This study demonstrates that insulin resistance determined with the HOMA model is associated with a high grade of steatosis in patients with NAFLD.
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PMID:Influence of insulin resistance and adipokines in the grade of steatosis of nonalcoholic fatty liver disease. 1793 20

Steatosis is an important cofactor in hepatitis C virus (HCV) because it is associated with fibrosis and reduces early and sustained virologic response. Recent studies suggest that HCV genotype 1 is not steatogenic if additional risk factors are not present. Because hypoadiponectinemia was found to be a feature of nonalcoholic steatohepatitis (NASH) independent of insulin resistance, its level in patients with hepatitis C genotype can reveal the optimal therapeutic strategy. This study was conducted to determine the role of the relationship between steatosis and serum adiponectin levels in the progression of liver damage in HCV genotype 1 without known risk factors for NASH. Patients (n=50) with biopsy-proven chronic hepatitis C (CHC), positive HCV RNA, and raised alanine aminotransferase were enrolled. They were carefully selected to rule out possible confounding factors for the presence of steatosis and additional systemic or liver disease. Associations between serum adiponectin levels and grade of steatosis, histologic activity index (HAI), fibrosis grade of liver biopsies, patient age, HCV viral load, and serum transaminase activities were studied. Also, adiponectin levels were compared with those of a control group of 30 healthy volunteers with normal ultrasound findings of the upper abdomen who had no known NASH risk factors. The investigators found that adiponectin levels in patients with CHC genotype 1 were similar to those in healthy subjects. No significant association was found between adiponectin levels and severity of steatosis, HCV RNA levels, HAI, transaminases, and fibrosis. Steatosis was present in 41 patients (82%) with CHC. Multivariate analysis of data on 50 patients revealed that severity of steatosis was independently related to age alone (P=.03). A correlation between HCV RNA load and HAI was observed (P=.02; r=0.712). HAI also was associated with stage of fibrosis (P=.00; r= 0.612). In cases of chronic HCV genotype 1 hepatitis, steatosis is a common histologic feature, although no risk factors are known. Results presented here cannot establish an association between adiponectin and severity of steatosis when risk factors for steatosis are unknown. Additional studies are needed to discover a metabolic treatment that would seek to improve the progression of hepatic steatosis in CHC infection.
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PMID:Correlation of serum adiponectin levels and hepatic steatosis in hepatitis C virus genotype 1 infection. 1802 22

Dyslipidemia and fatty liver are important components of the metabolic syndrome and are the factors most commonly associated with the development of nonalcoholic fatty liver disease. Delayed and excessive insulin secretion in response to food intake is a key element in the onset of these risk factors. Nateglinide (NAT) is known to restore early-phase insulin secretion. We assessed the effect of NAT on postprandial hypertriglyceridemia and fatty liver in type 2 diabetic Goto-Kakizaki (GK) rats. The GK rats fed a high-fat diet containing 30% beef tallow twice a day were administered either the vehicle alone or NAT (50 mg/kg) before each meal for 12 weeks. Delayed insulin secretion and an increase of total insulin release were caused by feeding 30% beef tallow to the rats. This diet also induced postprandial hypertriglyceridemia and increased the hepatic triglyceride content. Treatment with NAT restored early-phase insulin secretion without any increase of total insulin release and also reduced postprandial hypertriglyceridemia and the hepatic triglyceride content. There was up-regulation of the hepatic expression of peroxisome proliferators-activated receptor alpha and its downstream enzymes after 12 weeks of NAT treatment, as well as normalization of the plasma total ketone body level. Furthermore, NAT also up-regulated hepatic expression of the adiponectin receptor AdipoR2, although there was no effect on the plasma adiponectin level. These findings indicate that long-term treatment with NAT prevented the development of fatty liver through the up-regulation of hepatic lipid oxidation pathways. Restoration of early-phase insulin secretion and suppression of recurrent postprandial hypertriglyceridemia might be involved in these effects of NAT. The present results may support the use of NAT to prevent the onset and progression of the metabolic syndrome and chronic liver disease.
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PMID:Nateglinide prevents fatty liver through up-regulation of lipid oxidation pathway in Goto-Kakizaki rats on a high-fat diet. 1807 71

The incidence of nonalcoholic fatty liver disease (NAFLD) has risen along with the ongoing obesity epidemic. Green tea extract (GTE) inhibits intestinal lipid absorption and may regulate hepatic lipid accumulation. The objective of this study was to determine whether GTE protects against hepatic lipid accumulation during the development of NAFLD in an obese mouse model. Five-wk-old ob/ob (obese) mice and their lean littermates (8 mice x genotype(-1) x dietary treatment(-1)) were fed GTE at 0, 1, or 2% (wt:wt) for 6 wk. The body weights of obese mice and lean littermates fed diets containing GTE were 23-25% and 11-20% lower (P < 0.05) than their respective controls fed no GTE. Histologic evaluation showed a significant reduction in hepatic steatosis in GTE-fed obese mice only and histologic scores were correlated with hepatic lipid concentration (r = 0.84; P < 0.05), which was reduced dose dependently by GTE. GTE protected against hepatic injury as suggested by 30-41% and 22-33% lower serum alanine aminotransferase and aspartate aminotransferase activities, respectively. Hepatic alpha-tocopherol was 36% higher in obese mice than lean mice. GTE tended (P = 0.06) to lower hepatic alpha-tocopherol, which was not fully explained by the GTE-mediated reduction in hepatic lipid. Hepatic ascorbic acid was lower in obese mice than in lean mice (P < 0.05) and was unaltered by GTE. Obese mice had lower serum adiponectin than lean mice and this was not affected by GTE. The results suggest that GTE protects against NAFLD by limiting hepatic lipid accumulation and injury without affecting hepatic antioxidant status and adiponectin-mediated lipid metabolism. Further study is underway to define the events by which GTE protects against obesity-triggered NAFLD.
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PMID:Green tea extract protects leptin-deficient, spontaneously obese mice from hepatic steatosis and injury. 1820 99

Recent studies have demonstrated that n-3 polyunsaturated fatty acids ameliorate nonalcoholic fatty liver disease. Although eicosapentaenoic acid (EPA), one of the major components of n-3 polyunsaturated fatty acids, is widely used as an antilipidemic agent, its single efficacy for nonalcoholic steatohepatitis (NASH) remains unclear. As such, we aimed to evaluate the efficacy and safety of EPA on 23 biopsy-proven NASH patients in a pilot trial. Highly purified EPA (2700 mg/d) was administered for 12 months and efficacy was assessed by biochemical parameters and liver histology. All patients completed the treatment with no adverse events, indicating acceptable tolerance to the treatment. After 12 months, serum alanine aminotransferase levels were significantly improved (from 79+/-36 to 50+/-20 U/L), and serum free fatty acids, plasma soluble tumor necrosis factor receptor 1 and 2 levels, and serum ferritin and thioredoxin levels, which may reflect hepatic oxidative stress, were significantly decreased. Body weight, blood glucose, insulin, and adiponectin concentrations remained unchanged. Seven of the 23 patients consented to undergo posttreatment liver biopsy, which showed improvement of hepatic steatosis and fibrosis, hepatocyte ballooning, and lobular inflammation in 6 patients. In conclusion, EPA treatment seems to be safe and efficacious for patients with NASH, largely due to its anti-inflammatory and antioxidative properties. To confirm these results, appropriately powered, controlled trials are needed.
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PMID:Highly purified eicosapentaenoic acid treatment improves nonalcoholic steatohepatitis. 1827 95


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