Nonalcoholic fatty liver disease (NAFLD) has been associated with the insulin-resistance syndrome, at present defined as the metabolic syndrome, whose limits were recently set. We assessed the prevalence of the metabolic syndrome in 304 consecutive NAFLD patients without overt diabetes, on the basis of 3 or more criteria out of 5 defined by the U.S. National Institutes of Health (waist circumference, glucose, high-density lipoprotein [HDL]-cholesterol, triglycerides, and arterial pressure). The prevalence of the metabolic syndrome increased with increasing body mass index, from 18% in normal-weight subjects to 67% in obesity. Insulin resistance (Homeostasis Model Assessment method) was significantly associated with the metabolic syndrome (odds ratio [OR], 2.5; 95% CI, 1.5-4.2; P < .001). Liver biopsy was available in 163 cases (54%). A total of 120 patients (73.6%) were classified as having nonalcoholic steatohepatitis (NASH); 88% of them had a metabolic syndrome (vs. 53% of patients with pure fatty liver; P < .0001). Logistic regression analysis confirmed that the presence of metabolic syndrome carried a high risk of NASH among NAFLD subjects (OR, 3.2; 95% CI, 1.2-8.9; P ‫؍‬ .026) after correction for sex, age, and body mass. In particular, the syndrome was associated with a high risk of severe fibrosis (OR, 3.5; 95% CI, 1.1-11.2; P ‫؍‬ .032). In conclusion, the presence of multiple metabolic disorders is associated with a potentially progressive, severe liver disease. The increasing prevalence of obesity, coupled with diabetes, dyslipidemia, hypertension, and ultimately the metabolic syndrome puts a very large population at risk of forthcoming liver failure in the next decades. (HEPATOLOGY 2003;37:917-923.)

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Inherited factors play a major role in the predisposition to nonalcoholic fatty liver disease (NAFLD), and the rs738409 CfiG polymorphism of PNPLA3/adiponutrin, encoding for the isoleucine-to-methionine substitution at residue 148 (I148M) protein variant, has recently been recognized as a major determinant of liver fat content. However, the effect of the rs738409 polymorphism on the severity of liver fibrosis in patients with NAFLD is still unknown. In this study, we considered 253 Italian patients, 179 healthy controls, and 71 family trios with an affected child with NAFLD. Analyses were replicated in 321 patients from the United Kingdom. The rs738409 polymorphism was determined by TaqMan assays. Liver histology was scored according to Kleiner et al. Hepatic expression of genes regulating liver damage was assessed by real-time polymerase chain reaction in 52 patients. The rs738409 GG genotype was more prevalent in patients than in controls (14% versus 3%, adjusted odds ratio [OR] 5 3.29, 95% confidence interval [CI] 5 1.8-6.9), and in the family study, the G allele was overtransmitted to affected children (P 5 0.001). In Italian and United Kingdom patients, adiponutrin genotype influenced alanine aminotransferase levels and the severity of steatosis. Adiponutrin genotype was associated with the expression of genes involved in the steatosis-related liver damage, including the proapoptotic molecule Fas ligand. In the whole series combined, adiponutrin genotype was associated with steatosis grade >1 (OR 5 1.35, 95% CI 5 1.04-1.76), nonalcoholic steatohepatitis (OR 5 1.5, 95% CI 5 1.12-2.04), and fibrosis stage >1 (OR 5 1.5, 95% CI 5 1.09-2.12), independent of age, body mass index, and diabetes. Adiponutrin genotype demonstrated a dose effect with heterozygote risk intermediate between CC and GG homozygotes. Conclusion: In patients with NAFLD, adiponutrin rs738409 CfiG genotype, encoding for I148M, is associated with the severity of steatosis and fibrosis and the presence of nonalcoholic steatohepatitis. (HEPATOLOGY 2010;51:1209-1217 Abbreviations: ALT, alanine aminotransferase; FASL, Fas ligand; FFA, free fatty acid; HDL, high-density lipoprotein; INSR, insulin receptor; LDL, low-density lipoprotein; mRNA, messenger RNA; NAFLD, nonalcoholic fatty liver disease; NASH, nonalcoholic steatohepatitis; PNPLA3, patatin-like phospholipase-3; PPARa, peroxisome proliferator-activated receptor-a; qRT-PCR, quantitative real-time polymerase chain reaction; a-SMA, a-smooth muscle actin; SNP, single-nucleotide polymorphism; SREBP1c, steroid regulatory element binding protein 1c.From the

Aims/Hypothesis: Non-alcoholic fatty liver disease (NAFLD) has been associated with the metabolic syndrome. However, it is not clear whether insulin resistance is an independent feature of NAFLD, and it remains to be determined which of the in vivo actions of insulin are impaired in this condition. Methods: We performed a twostep (1.5 and 6 pmol min −1 kg −1 ) euglycaemic insulin clamp coupled with tracer infusion ([6,6-2 H 2 ]glucose and [ 2 H 5 ] glycerol) and indirect calorimetry in 12 non-obese, normolipidaemic, normotensive, non-diabetic patients with biopsy-proven NAFLD and six control subjects. Results: In NAFLD patients, endogenous glucose production (basal and during the clamp) was normal; however, peripheral glucose disposal was markedly decreased (by 30% and 45% at the low and high insulin doses, respectively, p<0.0001) at higher plasma insulin levels (p=0.05), due to impaired glucose oxidation (p=0.003) and glycogen synthesis (p<0.001). Compared with control subjects, glycerol appearance and lipid oxidation were significantly increased in NAFLD patients in the basal state, and were suppressed by insulin to a lesser extent (p<0.05-0.001). The lag phase of the in vitro copper-catalysed peroxidation of LDL particles was significantly shorter in the patients than in the control subjects (48±12 vs 63±13 min, p<0.04). Lipid oxidation was significantly related to endogenous glucose production, glucose disposal, the degree of hepatic steatosis, and LDL oxidisability. Conclusions/interpretation: Insulin resistance appears to be an intrinsic defect in NAFLD, with the metabolic pattern observed indicating that adipose tissue is an important site.

It is uncertain whether patients with nonalcoholic fatty liver disease (NAFLD) and normal alanine aminotransferase (ALT) have a milder disease and should undergo liver biopsy. We reviewed the histological data of 458 Italian patients with NAFLD in whom liver biopsy was indicated by altered liver enzymes (395 cases, 86%), or persistently elevated ferritin or longlasting severe steatosis (63 cases). Factors associated with nonalcoholic steatohepatitis (NASH) and fibrosis > 2 were identified by multivariate analysis. Patients with normal ALT were significantly older, had lower body mass index, fasting triglycerides, insulin resistance according to homeostasis model assessment (HOMA-IR), ALT, and gamma-glutamyltransferase, but a higher prevalence of hypertension. NASH was diagnosed in 59% and 74% of the patients with normal and increased ALT, respectively (P ‫؍‬ 0.01). In the overall series of patients, NASH was independently predicted by ALT (odds ratio [OR], 1.11; 95% confidence interval [CI], 1.04-1.19 per 10-IU/mL increase) and diabetes (OR, 1.5; 95% CI, 1.1-2.0). The same variables were selected in patients with increased ALT, whereas in those with normal ALT, HOMA-IR and ALT were independent predictors. Severe fibrosis was independently predicted by serum ferritin (OR, 1.04; 95% CI, 1.001-1.08 per 50-ng/mL increase), ALT (OR, 1.07; 95% CI, 1.02-1.14), and diabetes (OR, 1.8; 95% CI, 1.4-2.3) in the overall series, serum ferritin and diabetes in those with increased ALT, and only HOMA-IR (OR, 1.97; 95% CI, 1.2-3.7) in patients with normal ALT. Conclusion: Normal ALT is not a valuable criterion to exclude patients from liver biopsy. Alterations in glucose metabolism and insulin resistance in subjects with normal ALT should also be considered in the selection of NAFLD cases for histological assessment of disease severity and progression. (HEPATOLOGY 2008;48:792-798.)

Metformin treatment is better than a prescriptive diet or vitamin E in the therapy of NAFLD patients receiving nutritional counseling. Limited histological data support an association between improved aminotransferases and biopsy findings, which require confirmation in a double-blind trial with appropriate statistical power based on liver histology.

Nonalcoholic fatty liver disease (NAFLD) is consistently associated with features of the metabolic syndrome, a condition carrying a high risk of cardiovascular events. We measured the vasodilatory response of the brachial artery in response to ischemia (a test of endothelial function) (FMV) as well as cardiovascular risk profile in 52 NAFLD cases and 28 age-and sex-matched controls. The 10-year risk of coronary events was calculated according to the Framingham equation and the scores derived from the PROCAM study and NCEP-ATPIII proposals. FMV was 6.33% ؎ 5.93% in NAFLD versus 12.22% ؎ 5.05% in controls (P < .0001), and higher in pure fatty liver (9.93%) compared with nonalcoholic steatohepatitis (4.94%) (P ‫؍‬ .010). No differences were observed in flow-independent vasodilation (response to sublingual nitroglycerin). Percent FMV was negatively associated with insulin resistance (homeostasis model assessment) in the whole population (r ‫؍‬ ؊0.243; P ‫؍‬ .030). In logistic regression analysis, NAFLD was associated with a percent FMV in the lower tertile (OR, 6.7; 95% CI, 1.26-36.1), after adjustment for age, sex, body mass index, and insulin resistance. Among NAFLD patients, low FMV was associated with nonalcoholic steatohepatitis (adjusted OR, 6.8; 95% CI, 1.2-40.2). The 10-year probability of cardiovascular events was moderately increased in NAFLD, and particularly in nonalcoholic steatohepatitis. In conclusion, our study provides evidence of endothelial dysfunction and increased risk of cardiovascular events in NAFLD. The risk of advanced liver disease is well recognized in NAFLD patients, but the large majority of cases might experience cardiovascular disease in the long term, indirectly limiting the burden of liver failure. (HEPATOLOGY 2005;42:473-480.)

The metabolic syndrome encompasses metabolic and cardiovascular risk factors which predict diabetes and cardiovascular disease (CVD) better than any of its individual components. Nonalcoholic fatty liver disease (NAFLD) comprises a disease spectrum which includes variable degrees of simple steatosis (nonalcoholic fatty liver, NAFL), nonalcoholic steatohepatitis (NASH) and cirrhosis. NAFLD is the hepatic manifestation of the metabolic syndrome, with insulin resistance as the main pathogenetic mechanism. Recent data indicate that hyperinsulinemia is probably the consequence rather than cause of NAFLD and NAFLD can be considered an independent predictor of cardiovascular disease. Serum free fatty acids derived from lipolysis of visceral adipose tissue are the main source of hepatic triglycerides in NAFLD, although hepatic de novo lipogenesis and dietary fat supply contribute to the pathogenesis of NAFLD. Approximately 10-25% NAFLD patients develop NASH, the evolutive form of hepatic steatosis. Presumably in a genetically predisposed environment, this increased lipid overload overwhelms the oxidative capacity and reactive oxygen species are generated, leading to lipid peroxidation, cytokine induction, chemoattraction of inflammatory cells, hepatic stellate cell activation and finally fibrogenesis with extracellular matrix deposition. No currently available therapies for NAFLD and NASH exist. Recently nuclear receptors have emerged as key regulators of lipid and carbohydrate metabolism for which specific pharmacological ligands are available, making them attractive therapeutic targets for NAFLD and NASH.Abbreviations ALT, alanine aminotransferase; BMI, body mass index; CVD, cardiovascular disease; FFA, free fatty acids; HDL, high density lipoprotein; 1H-MRS, proton magnetic resonance spectroscopy; IDF, International Diabetes Federation; LDL, low density lipoprotein; NAFLD, nonalcoholic fatty liver disease; SNP, single nucleotide polymorphism; VLDL, very low density lipoprotein IntroductionThe metabolic syndrome is a cluster of metabolic and cardiovascular risk factors which predicts diabetes and cardiovascular disease (CVD) better than any of its individual components [1]. The latest definition of the metabolic syndrome by International Diabetes Federation (IDF) includes abdominal obesity defined by increased waist circumference (≥94 cm in men and ≥80 cm in women) and two or more of the following features: elevated blood pressure, fasting glucose or triglyceride concentrations, or low HDL cholesterol [1]. The term nonalcoholic fatty liver disease (NAFLD) comprises a disease spectrum which includes variable degrees of simple steatosis (nonalcoholic fatty liver, NAFL), nonalcoholic steatohepatitis (NASH) and cirrhosis [2] and [3]. NAFLD can be considered the hepatic manifestation of the metabolic syndrome. Simple steatosis is benign, whereas NASH is defined by the presence of hepatocyte injury, inflammation and/or fibrosis which can lead to cirrhosis, liver failure and hepatocellular carcinoma. In contrast to t...