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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanism(s) determining the progression from fatty liver to steatohepatitis is currently unknown. Our goal was to define the relative impact of iron overload, genetic mutations of HFE, and insulin resistance on the severity of liver fibrosis in a population of subjects with nonalcoholic fatty liver disease (NAFLD) who had low prevalence of obesity and no overt symptoms of diabetes. In a cohort of 263 prospectively enrolled patients with NAFLD, 7.4% of patients had signs of peripheral iron overload and 9% had signs of hepatic iron overload, but 21.1% had hyperferritinemia. The prevalence of C282Y and H63D HFE mutations was similar to the general population and mutations were not associated with iron overload. Although subjects were on average only moderately overweight, insulin sensitivity, measured both in the fasting state and in response to oral glucose, was lower. Univariate analysis demonstrated that the presence of severe fibrosis was independently associated with older age, female sex, overweight, aspartate/alanine aminotransferase ratio, serum ferritin level, fasting glucose and insulin levels, decreased insulin sensitivity, and with histologic features (degree of necroinflammation and steatosis). After adjustment for body mass index (BMI), age, sex, and degree of steatosis, ferritin levels (odds ratio [OR] = 1.77; 95% CI = 1.21- 2.58; P =.0032) and the oral glucose insulin sensitivity (OR = 0.53; CI = 0.33-0.87; P =.0113) were independent predictors of severe fibrosis. In conclusion, the current study indicates that insulin resistance is a major, independent risk factor for advanced fibrosis in patients with NAFLD. Increased ferritin levels are markers of severe histologic damage, but not of iron overload. Iron burden and HFE mutations do not contribute significantly to hepatic fibrosis in the majority of patients with NAFLD.
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PMID:Relative contribution of iron burden, HFE mutations, and insulin resistance to fibrosis in nonalcoholic fatty liver. 1518 21

Non-alcoholic steatohepatitis (NASH) can vary from mild hepatic inflammation and steatosis to cirrhosis, and is most frequently associated with obesity, Type 2 diabetes mellitus, hypertension, and the female gender. The prevalence of fatty liver and NASH in the general population is 20% and 3%, respectively. In Western countries, 15-20% of the population is obese and 74-90% of them exhibit fatty changes in liver biopsies. We assessed the prevalence of NASH in morbidly obese patients and evaluated serum TGF-beta1 concentrations in different stages of liver fibrosis. Thirty-five obese patients were evaluated, nine male and 26 female. Their mean body mass index (BMI) was 43.62 +/- 7.92 kg/m2. Liver biopsies were evaluated by light microscopy; graded and staged according to Brunt's system. Serum obtained from patients was used to detect TGF-beta1 concentrations by an ELISA method. Serum alanine transaminase (ALT) levels were elevated in four of the patients and the mean level was 49.98 +/- 94.7 (8-65 IU/L). NASH was diagnosed in 32 (91%) of the biopsies, and the most common pattern seen was mixed, predominantly macrovesicular steatosis. Some degree of fibrosis was seen in 34 (97%) of the biopsies and 22 (63%) were at stage 2 (range 1-3). Serum concentrations of TGF-beta1 had no relationship with the stages of fibrosis. In conclusion, NASH and fibrosis are common in our obese patients, as observed in other studies. TGF-beta1 may play a key role in liver fibrogenesis.
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PMID:Obesity-related non-alcoholic steatohepatitis and TGF-beta1 serum levels in relation to morbid obesity. 1511 94

Obesity and type 2 diabetes are associated with nonalcoholic steatohepatitis (NASH), but an obese/diabetic animal model that mimics human NASH remains undefined. We examined the induction of steatohepatitis and liver fibrosis in obese and type 2 diabetic db/db mice in a nutritional model of NASH and determined the relationship of the expressions of osteopontin (OPN) and leptin receptors to the pathogenesis of NASH. db/db mice and the corresponding lean and nondiabetic db/m mice were fed a diet deficient in methionine and choline (MCD diet) or control diet for 4 wk. Leptin-deficient obese and diabetic ob/ob mice fed similar diets were used for comparison. MCD diet-fed db/db mice exhibited significantly greater histological inflammation and higher serum alanine aminotransferase levels than db/m and ob/ob mice. Trichrome staining showed marked pericellular fibrosis in MCD diet-fed db/db mice but no significant fibrosis in db/m or ob/ob mice. Collagen I mRNA expression was increased 10-fold in db/db mice, 4-fold in db/m mice, and was unchanged in ob/ob mice. mRNA expressions of OPN, TNF-alpha, TGF-beta, and short-form leptin receptors (Ob-Ra) were significantly increased in db/db mice compared with db/m or ob/ob mice. Parallel increases in OPN and Ob-Ra protein levels were observed in db/db mice. Cultured hepatocytes expressed only Ob-Ra, and leptin stimulated OPN mRNA and protein expression in these cells. In conclusion, our results demonstrate the development of an obese/diabetic experimental model for NASH in db/db mice and suggest an important role for Ob-Ra and OPN in the pathogenesis of NASH.
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PMID:Obese and diabetic db/db mice develop marked liver fibrosis in a model of nonalcoholic steatohepatitis: role of short-form leptin receptors and osteopontin. 1525 62

Nonalcoholic steatohepatitis may cause severe fibrosis, cirrhosis, and hepatocellular carcinoma, but supporting evidence is based on indirect data. Few publications have examined the results of repeat liver biopsies to evaluate progression of fibrosis. The aims of this study were to assess rate of fibrosis progression in untreated patients with nonalcoholic steatohepatitis and to identify associated variables. Among 106 patients, a second liver biopsy was proposed to those who had undergone their first liver biopsy at least 3 years before. None of them had been given pharmacological therapy. Liver biopsy samples were evaluated blindly. Variables were compared between patients with (group P) and without (group NP) fibrosis progression, using a Wilcoxon rank-sum test for numerical variables and a difference of two binomial proportions for categorical ones. Twenty-two patients (median age, 45 years; age range, 20-69 years; 13 women; diabetes in 8 patients, obesity in 10 patients) underwent a second liver biopsy 4.3 years (range, 3.0-14.3 years) after the first. Fibrosis progression was found in 7 patients in group P (31.8%), no progression was found in 15 patients in group NP. There were no differences between both groups regarding age, gender, diabetes, hyperlipidemia, ALT levels, AST-to-ALT ratio levels, albumin levels, prothrombin activity, steatosis, or inflammation. Obesity was significantly more prevalent in group P (86%) than in group NP (27%; P =.01). Basal body mass index was higher in group P (median, 33.2; range, 29.1-38.2) than in group NP (median, 29.0; range, 24.0-38.1; P =.024). Time between biopsies was not different between groups. In conclusion, progression of liver fibrosis was found in a third of nonalcoholic steatohepatitis patients 4.3 years after the first liver biopsy, and obesity and body mass index were the only associated factors with such progression.
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PMID:Natural history of nonalcoholic steatohepatitis: a longitudinal study of repeat liver biopsies. 1538 71

Non-alcoholic fatty liver disease (NAFLD) is a frequent syndrome encompassing fatty liver alone and steatohepatitis (NASH). Often asymptomatic, the suspicion arises because of abnormal aminotransferases or a bright liver on abdominal ultrasound. It should be suspected during evaluation of associated conditions as obesity, diabetes or dyslipidaemia. The diagnostic evaluation must exclude other potential causes of liver disease and may include a liver biopsy, the only method able to confirm features of necroinflammation and fibrosis that define NASH and its prognostic implications. Indeed, the presence of necroinflammation has been associated with a significant risk of progression to cirrhosis and eventually hepatocellular carcinoma. Age >45 years, obesity and diabetes have also been associated with an increased risk of liver fibrosis and progression to cirrhosis. Given the high prevalence of NAFLD, general measures of life-style changes, focusing on exercise, diet, and total alcohol abstinence, should be implemented before a liver biopsy is considered.
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PMID:Non-alcoholic fatty liver disease/non-alcoholic steatohepatitis (NAFLD/NASH): diagnosis and clinical course. 1556 40

Obesity is a rapidly growing health issue in Mexico and throughout the world because it is perceived as an alarming threat directly related with lifestyle in both children and adults, although cardiovascular, metabolic, neoplasic, and sleep-disorder complications of obesity are being investigated. However, overweight is a risk factor for chronic liver disease because liver fibrosis can develop in overweight patients free of any other known causes of liver disease. Obesity has been associated with development of hepatocellular carcinoma.
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PMID:[Obesity and its association with cryptogenic cirrhosis and hepatocarcinoma]. 1564 76

Liver fibrosis is the consequence of chronic or repeated liver injury caused by hepatotoxic agents like alcohol and viruses, as well as immune and congenital metabolic disorders. Nonalcoholic fatty liver disease (NAFLD), caused by obesity and abnormal lipid metabolism, may be the latest known cause of liver fibrosis and cirrhosis. Furthermore, NAFLD with obesity can provide a terrain in which alcoholic and viral liver diseases, such as chronic hepatitis C, are prone to cause liver cirrhosis. Insulin, insulin-like growth factor (IGF)-1, peroxisome proliferator-activated receptors (PPARs), leptin, adiponectin, and preadipocyte factor-1/delta-like1 (Pref-1/dlk1) are hormones, growth factors, nuclear receptors, and cytokines that are actively involved in lipid metabolism. They share common target cells important in liver fibrosis, i.e., hepatic stellate cells (HSCs). Activation of HSCs is known to initiate and perpetuate liver fibrosis. Insulin and IGF-1 stimulate HSC activation and collagen production in vitro. However, IGF-1 alleviates liver fibrosis in vivo. Ligands of PPARy inhibit HSC activation and collagen synthesis in vivo and in vitro, and are helpful in decreasing liver fibrosis. But ligands of PPARbeta enhance proliferation of HSCs. Leptin is profibrogenic, and liver fibrosis is decreased in leptin- or leptin receptor-deficient mice. Adiponectin is, on the contrary, anti-fibrogenic. Extensive liver fibrosis may develop in adiponectin-knockout mice and is alleviated by administration of recombinant adiponectin. Pref-1/dlkl is implicated in fibrogenesis of the liver through its modulation of HSCs. The use of such biologically active molecules in lipid metabolism as ligands of PPARgamma and adiponectin might not help slim down a patient on the whole, but can potentially be used to halt the progression of liver fibrosis. Weight reduction, a strategy for controlling obesity and metabolic syndromes, may also be a tool for decreasing NAFLD and alleviating liver cirrhosis.
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PMID:An adipocentric view of liver fibrosis and cirrhosis. 1575 75

Hepatic steatosis is the hallmark of nonalcoholic fatty liver disease (NAFLD), which is the consequence of multiple metabolic derangements among which insulin resistance plays a pivotal role. Steatosis is, also, a feature of hepatitis C virus (HCV) infection. However, in chronic hepatitis C, the prevalence of steatosis is 2.5-fold more elevated than that expected by a chance concurrence with NAFLD, suggesting that HCV may be implied in the development of steatosis. As observed in NAFLD, in patients infected with HCV genotype 1 steatosis is associated with an increased body mass index. On the other hand, in patients infected with genotype 3 the extent of steatosis strictly correlates with the viral load indicating that steatosis is mainly "virus-related". Regardless of the "metabolic" or "viral" etiology, hepatic steatosis in HCV contributes to the progression of liver fibrosis, to the development of hepatocellular carcinoma and to an impaired response to interferon treatment. Features such as obesity, insulin resistance and type 2 diabetes mellitus are shared by NAFLD and HCV-associated steatosis. In addition, HCV infection, directly or through steatosis, favors the development of type 2 diabetes mellitus. Hyperlipidemia is an independent predictor of the development of NAFLD, but not of HCV-associated steatosis. Arterial hypertension is common in nonalcoholic steatohepatitis patients, and HCV infection has recently been acknowledged as an independent risk factor for atherosclerosis. The role of iron in the progression of both NAFLD and HCV-associated steatosis remains controversial while lipoperoxidation and oxidative stress are pathogenic mechanisms shared by both. Some metabolic risk factors may be shared by both HCV-associated steatosis and NAFLD although the disease progression and pathophysiological background may be different. Preliminary data suggest that the therapeutic options for NAFLD may also be useful to improve HCV-associated steatosis.
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PMID:[Hepatitis C virus-associated and metabolic steatosis. Different or overlapping diseases?]. 1585 90

Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a nuclear transcription factor that comprises the primary molecular target for thiazolidinedione (TZD) insulin-sensitizing drugs. Whilst expressed in many tissues in humans, its abundant expression in adipose tissue is believed to be the focal point through which TZDs regulate genes involved in glucose and lipid metabolism and via which these agents ultimately improve the hyperglycemia of type 2 diabetes. However, TZDs exhibit many additional properties, not least an array of effects which suggest a broad attack on the inflammatory process. Thus, TZDs have been shown to reduce plasma levels of the chemokine, monocyte chemotactic protein-1 (MCP-1), the anti-fibrinolytic protein, plasminogen activator inhibitor-1 (PAI-1), the endothelial cell adhesion molecules, e-selectin and inter-cellular adhesion molecule-1 (ICAM-1), the leucocyte-activating molecule, CD40L, and the tissue-remodeling enzyme, matrix metalloproteinase-9 (MMP-9). Further tangible evidence of a reduction by TZDs of systemic inflammation in patients with the classical metabolic syndrome stems from falls in the white blood cell count, P-selectin-positive platelets and in the acute-phase inflammatory proteins, C-reactive protein, serum amyloid A and fibrinogen. At the tissue level, TZDs improve vascular endothelial function, and reduce the rate of progression of intimal-medial thickening of the carotid artery and the microalbuminuria of type 2 diabetes. Further, TZDs have been shown to be efficacious in inflammatory diseases as wide-ranging as psoriasis, ulcerative colitis and non-alcoholic steatohepatitis (NASH). In the case of the latter, a broad spectrum of TZD-related properties is visible. Here, these drugs improve insulin sensitivity for glucose metabolism, reduce hyperinsulinemia, hepatic steatosis, inflammation and fibrosis, and lower the circulating levels of liver transaminases (ALT, AST), alkaline phosphatase and gamma glutamyl transferase. These effects in humans are also well-supported by investigative animal and in vitro studies. The ameliorative effects on liver fibrosis are of particular interest since they suggest that TZDs are able to activate a program of corrective tissue-remodeling. The basis for this action may be partly an ability to inhibit matrix protein secretion by hepatic stellate cells. An analogous action has also been seen in kidney mesangial cells. In conclusion, TZDs are important new drugs, presently indicated for the treatment of type 2 diabetes but with a spectrum of properties which suggests their potential for treating a number of degenerative inflammatory diseases, including NASH. However, full-scale, long-term clinical trials are needed with TZDs to test their potential to treat NASH, not least because of the (hepatotoxic) legacy of the prototype TZD, troglitazone, but also in view of the escalating burden of liver disease which is accompanying the increasing global prevalence of clinical obesity and type 2 diabetes.
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PMID:Thiazolidinediones: Pleiotropic drugs with potent anti-inflammatory properties for tissue protection. 1619 19

Since non-alchoholic steatohepatitis (NASH) is often accompanied with metabolic syndrome comprising obesity, type-2 diabetes and hypertension, it is hypothesized that adipocytokines, insulin resistance and autonomic nervous system play crucial roles in disease progression of NASH. On the other hand, hepatic stellate cells (HSCs) have been shown to produce leptin when they get activated during hepatic fibrogenesis. Therefore, we investigated the role of leptin in fibrogenesis in the liver. Xenobiotics-induced liver fibrosis was extremely diminished in ob/ob mice and Zucker (fa/fa) rats, an inborn leptin- and leptin receptor (Ob-R)-deficient animal, respectively. Further, leptin increased transforming growth factor (TGF)-beta mRNA in isolated sinusoidal endothelial cells and Kupffer cells, suggesting that leptin promotes hepatic fibrogenesis through up-regulation of TGF-beta in the liver. Moreover, leptin augmented PDGF-dependent proliferation of HSCs by enhancing downstream intracellular signaling pathways via mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3 kinase (PI3K)/Akt. Taken together, it is postulated that leptin acts as a profibrogenic cytokine in sinusoidal microenvironment. These findings indicate that leptin is one of the key regulators for inflammation and progression of fibrosis in various chronic liver diseases including NASH.
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PMID:The role of leptin in progression of non-alcoholic fatty liver disease. 1619 23


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