Non-alcoholic fatty liver disease and the metabolic syndrome: An update

De novo lipogenesis in health and disease

BACKGROUND

De novo lipogenesis (DNL) is a complex and highly regulated metabolic pathway. In normal conditions DNL converts excess carbohydrate into fatty acids that are then esterified to storage triacylglycerols (TGs). These TGs could later provide energy via β-oxidation. In human body this pathway is primarily active in liver and adipose tissue. However, it is considered to be a minor contributor to the serum lipid homeostasis. Deregulations in the lipogenic pathway are associated with diverse pathological conditions.

SCOPE OF REVIEW

The present review focuses on our current understanding of the lipogenic pathway with special reference to the causes and consequences of aberrant DNL.

MAJOR CONCLUSIONS

The deregulation of DNL in the major lipogenic tissues of the human body is often observed in various metabolic anomalies - including obesity, non-alcoholic fatty liver disease and metabolic syndrome. In addition to that de novo lipogenesis is reported to be exacerbated in cancer tissues, virus infected cells etc. These observations suggest that inhibitors of the DNL pathway might serve as therapeutically significant compounds. The effectiveness of these inhibitors in treatment of cancer and obesity has been suggested by previous works.

GENERAL SIGNIFICANCE

De novo lipogenesis - which is an intricate and highly regulated pathway - can lead to adverse metabolic consequences when deregulated. Therapeutic targeting of this pathway may open a new window of opportunity for combating various lipogenesis-driven pathological conditions - including obesity, cancer and certain viral infections.

Prediction of metabolic syndrome by non-alcoholic fatty liver disease in northern urban Han Chinese population: a prospective cohort study

Objectives

To explore the relationship between non-alcoholic fatty liver disease (NAFLD) and the metabolic syndrome (MetS), and evaluate the value of NAFLD as a marker for predicting the risk of MetS in a large scale prospective cohort from northern urban Han Chinese population.

Materials and Methods

A total of 17,920 MetS-free at baseline cohort members was included in the current study between 2005 and 2011. The baseline characteristics of the cohort were compared by NAFLD status at baseline, MetS status after follow-up. Cox proportional hazards models were used to estimate the unadjusted or adjusted hazard ratios (HRs) for NAFLD at baseline predicting the risk of MetS.

Results

2,183 (12.18%) new cases of MetS occurred between 2005 and 2011. In unadjusted model, HRs (95% CIs) for NAFLD predicting MetS was 3.65 (3.35, 3.97). After adjusting the confounding factors of age, gender, the metabolic factors, smoke and exercise, the HRs (95% CIs) was 1.70 (1.55, 1.87). Gender difference was observed, adjusted HRs (95% CIs) of NAFLD for predicting MetS were 2.06(1.72, 2.46) and 1.55(1.39, 1.72) in female and male population, respectively. Moreover, 163 participants developed MetS among participants without any MetS component at baseline, and its adjusted HRs was still significant, 1.87 (1.12, 3.13).

Conclusion

The present study indicates that NAFLD is an independent risk factor for predicting the risk of MetS in northern urban Han Chinese population, and the people with NAFLD should initiate weight and dietary control to prevent the occurrence of MetS.

Nonalcoholic fatty liver disease and metabolic syndrome in postmenopausal women

Nonalcoholic fatty liver disease (NAFLD) is considered the most common cause of chronic liver disease in the Western countries. NAFLD includes a spectrum ranging from a simple steatosis to a nonalcoholic steatohepatitis (NASH) which is defined by the presence of inflammatory infiltrate, cellular necrosis, hepatocyte ballooning, and fibrosis and cirrhosis that can eventually develop into hepatocellular carcinoma. Studies emphasize the role of insulin resistance, oxidative stress, pro-inflammatory cytokines, adipokines in the development and progression of NAFLD. It seems to be independently associated with type II diabetes mellitus, increased triglycerides, decreased HDL-cholesterol, abdominal obesity and insulin resistance. These findings are in accordance with the criteria used in the diagnosis of metabolic syndrome (MetS). Here, we will discuss the current knowledge on the epidemiology, pathophysiology and diagnosis of NAFLD and the association of metabolic syndrome in postmenopausal women.

[Non-invasive markers of fibrosis in the diagnosis of non-alcoholic fatty liver disease]

OBJECTIVE

To analyze the utility of three indices to predict hepatic fibrosis in the detection of non-alcoholic fatty liver disease (NAFLD) as a non-invasive method in primary care.

DESIGN

We performed a descriptive, cross-sectional, multicenter study with a populational base from 25 primary care centers in the province of Barcelona.

PARTICIPANTS

Healthy individuals aged 17 to 83 years randomly selected from the Primary Care Computer System.

METHODS

Medical history, physical examination, and blood analyses were used to determine the following predictive indices of fibrosis; HAIR (hypertension, alanine-aminotransferase, insulin resistance); Fatty Liver Index (FLI) (body mass index, gammaglutamyl-transpeptidase, triglycerides, abdominal perimeter) and Lipid Accumulation Product (LAP) (triglycerides, abdominal perimeter), and abdominal echography.

RESULTS

We included 702 individuals; 58% were women and the mean age was 53±14 years. The FLI was positive in 30.8%, HAIR was positive in 6.7%, and LAP was positive in 15.5%. Agreement among the three indices ranged from 63.1% to 84.9%, with kappa indices between 0.18 and 0.50. A total of 184 individuals met the echographic criteria of NAFLD, representing a prevalence of 26.29%. The prevalence of NAFLD in patients with positive FLI, HAIR and LAP indices was 46.8%, 68.1% and 56%, respectively. The index with the greatest sensitivity for NAFLD was tFLI≥60 with 84%. Specificity was highest for HAIR and LAP with 97% and 91%, respectively.

CONCLUSIONS

FLI, HAIR and LAP are highly prevalent and have been shown to be independent markers for the diagnosis of NAFLD. Because of the lack of concordance between the indices, different prevalences are obtained, thus requiring criteria to be unified in order to obtain a more useful index for the diagnosis of NAFLD.

Evaluation of clinical and inflammatory markers of nonalcoholic fatty liver disease in postmenopausal women with metabolic syndrome

BACKGROUND

The aim of this study was to assess clinical and inflammatory markers in nonalcoholic fatty liver disease (NAFLD) in postmenopausal women with metabolic syndrome.

METHODS

This cross-sectional study included 180 Brazilian women (age ≥45 years and amenorrhea ≥12 months). Metabolic syndrome was diagnosed by the presence of at least three of the following indicators: Waist circumference (WC) >88 cm, triglycerides (TGs) ≥150 mg/dL, high-density lipoprotein (HDL) <50 mg/dL; blood pressure ≥130/85 mmHg; and glucose ≥100 mg/dL. NAFLD was diagnosed by abdominal ultrasound. Participants were divided into three groups: Metabolic syndrome alone (n=53); metabolic syndrome+NAFLD (n=67); or absence of metabolic syndrome or NAFLD (control, n=60). Clinical, anthropometric, and biochemical variables were quantified. The inflammatory profile included adiponectin, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Data were submitted to statistical analysis using a Tukey test, analysis of variance (ANOVA), chi-squared, Pearson correlation, and logistic regression (odds ratio, OR).

RESULTS

Women with metabolic syndrome+NAFLD, abdominal obesity, high glucose, and insulin resistance by HOMA-IR were compared to women with metabolic syndrome alone and controls (P<0.05). High values of IL-6 and TNF-α and low values of adiponectin were observed among women with metabolic syndrome alone or metabolic syndrome+NAFLD when compared to controls (P<0.05). In multivariate analysis, the variables considered as risk of NAFLD development were: High systolic blood pressure (SBP) [(OR 1.02, 95% confidence interval (CI) 1.0-1.04]; large WC (OR 1.07, 95% CI 1.01-1.13); insulin resistance (OR 3.81, 95% CI 2.01-7.13); and metabolic syndrome (OR 8.68, 95% CI 3.3-24.1). Adiponectin levels reduced NAFLD risk (OR 0.88, 95% CI 0.80-0.96).

CONCLUSION

In postmenopausal women, metabolic syndrome, abdominal obesity, and insulin resistance were risk markers for the development of NAFLD, whereas higher adiponectin values indicated a protection marker.

BL153 partially prevents high-fat diet induced liver damage probably via inhibition of lipid accumulation, inflammation, and oxidative stress

The present study was to investigate whether a magnolia extract, named BL153, can prevent obesity-induced liver damage and identify the possible protective mechanism. To this end, obese mice were induced by feeding with high fat diet (HFD, 60% kcal as fat) and the age-matched control mice were fed with control diet (10% kcal as fat) for 6 months. Simultaneously these mice were treated with or without BL153 daily at 3 dose levels (2.5, 5, and 10 mg/kg) by gavage. HFD feeding significantly increased the body weight and the liver weight. Administration of BL153 significantly reduced the liver weight but without effects on body weight. As a critical step of the development of NAFLD, hepatic fibrosis was induced in the mice fed with HFD, shown by upregulating the expression of connective tissue growth factor and transforming growth factor beta 1, which were significantly attenuated by BL153 in a dose-dependent manner. Mechanism study revealed that BL153 significantly suppressed HFD induced hepatic lipid accumulation and oxidative stress and slightly prevented liver inflammation. These results suggest that HFD induced fibrosis in the liver can be prevented partially by BL153, probably due to reduction of hepatic lipid accumulation, inflammation and oxidative stress.

Regular exercise coupled to diet regimen accelerates reduction of hepatic steatosis and associated pathological conditions in nonalcoholic fatty liver disease

BACKGROUND

A diet regimen focusing on weight loss is still the most efficient treatment for nonalcoholic fatty liver disease (NAFLD). Recently, specific benefits of exercise against NAFLD independent of weight loss have been reported. Hence, combining exercise with diet-induced weight loss can be expected to have an additive benefit for NAFLD management. We evaluated the effectiveness of diet in conjunction with exercise (DE) compared with that of diet alone (D) on hepatic steatosis and its underlying pathophysiology.

METHODS

Data obtained from 72 obese, middle-aged men with NAFLD who completed a 3-month program of DE or D in 2011 and 2012 were analyzed. Subjects went through a comprehensive parameters analysis for the pathophysiology of NAFLD.

RESULTS

Subjects in the DE group, compared with those in the D group, elicited additive effects on the degree of hepatic steatosis (-82.6% vs. -60.0%) and body weight (-13.3% vs. -8.9%) accompanied by an improvement in serum marker levels: inflammation, ferritin (-16.1% vs. -2.1%); oxidative stress, lipid peroxidation (-31.8% vs. +4.8%); adipokine imbalance, adiponectin, and leptin (+27.4% vs. +2.6% and -74.4% vs. -30.2%). Consequently, subjects in the DE group achieved further attenuation of insulin resistance [homeostatsis model assessment of insulin resistance (HOMA-IR) (-63.6% vs. -40.0%)]. These observed additive benefits in the DE group were closely associated with the increased volume of physical activity.

CONCLUSIONS

The addition of exercise to a diet regimen potentiates the benefits in NAFLD management through further improvement of hepatic steatosis, inflammatory and oxidative stress levels, and adipokine imbalance, thereby attenuating insulin resistance independent of detectable weight loss.

Association between serum soluble low-density lipoprotein receptor levels and metabolic factors in healthy Japanese individuals

BACKGROUND

Soluble low-density lipoprotein receptor (sLDL-R) is formed by cleavage of the extracellular domain of low-density lipoprotein receptor (LDL-R). It is unclear whether serum sLDL-R is a marker of diseases associated with triglyceride (TG) metabolism. We investigated the association between serum sLDL-R concentrations and other biochemical parameters in healthy Japanese individuals.

METHODS

Study subjects consisted of 102 healthy adult Japanese volunteers (42 men, 60 women) with body mass index (BMI) < 30 kg/m(2) and serum TGs, LDL cholesterol (LDL-C), aspartate aminotransferase, alanine aminotransferase, γ-glutamyl transpeptidase, and glucose concentrations within normal ranges. Serum sLDL-R concentrations were determined by enzyme-linked immunosorbent assay and their correlations with biochemical parameters were analyzed.

RESULTS

Mean serum sLDL-R concentration was 120.9 ± 39.9 ng/ml. Serum sLDL-R levels were significantly and positively correlated with BMI (rs = 0.252) and TG (rs = 0.408) and LDL-C (rs = 0.325) concentrations. Multiple regression analysis adjusted for age, gender, and smoking showed that BMI (β = 0.274), TG (β = 0.328), and LDL-C (β = 0.224) were factors independently correlated with sLDL-R levels.

CONCLUSION

Serum sLDL-R concentration may be a marker of diseases associated with TG metabolism. This is the first report to date describing the clinical relevance of sLDL-R.

Alpha-lipoic acid reduces LDL-particle number and PCSK9 concentrations in high-fat fed obese Zucker rats

We characterized the hypolipidemic effects of alpha-lipoic acid (LA, R-form) and examined the associated molecular mechanisms in a high fat fed Zucker rat model. Rats (n = 8) were assigned to a high fat (HF) diet or the HF diet with 0.25% LA (HF-LA) for 30 days and pair fed to remove confounding effects associated with the anorectic properties of LA. Compared with the HF controls, the HF-LA group was protected against diet-induced obesity (102.5±3.1 vs. 121.5±3.6,% change BW) and hypercholesterolemia with a reduction in total-C (−21%), non-HDL-C (−25%), LDL-C (−16%), and total LDL particle number (−46%) and an increase in total HDL particles (∼22%). This cholesterol-lowering response was associated with a reduction in plasma PCSK9 concentration (−70%) and an increase in hepatic LDLr receptor protein abundance (2 fold of HF). Compared with the HF-fed animals, livers of LA-supplemented animals were protected against TG accumulation (−46%), likely through multiple mechanisms including: a suppressed lipogenic response (down-regulation of hepatic acetyl-CoA carboxylase and fatty acid synthase expression); enhanced hepatic fat oxidation (increased carnitine palmitoyltransferase Iα expression); and enhanced VLDL export (increased hepatic diacylglycerol acyltransferase and microsomal triglyceride transfer protein expression and elevated plasma VLDL particle number). Study results also support an enhanced fatty acid uptake (2.8 fold increase in total lipase activity) and oxidation (increased CPT1β protein abundance) in muscle tissue in LA-supplemented animals compared with the HF group. In summary, in the absence of a change in caloric intake, LA was effective in protecting against hypercholesterolemia and hepatic fat accumulation under conditions of strong genetic and dietary predisposition toward obesity and dyslipidemia.

Reduced hepatic eNOS phosphorylation is associated with NAFLD and type 2 diabetes progression and is prevented by daily exercise in hyperphagic OLETF rats

We tested the hypothesis that nonalcoholic fatty liver disease (NAFLD) is associated with reduced hepatic endothelial nitric oxide synthase (eNOS) activation status via S1177 phosphorylation (p-eNOS) and is prevented by daily voluntary wheel running (VWR). Hyperphagic Otsuka Long-Evans Tokushima Fatty (OLETF) rats, an established model of obesity, type 2 diabetes (T2D) and NAFLD, and normophagic controls [Long-Evans Tokushima Otsuka (LETO)] were studied at 8, 20, and 40 wk of age. Basal hepatic eNOS phosphorylation (p-eNOS/eNOS) was similar between LETO and OLETFs with early hepatic steatosis (8 wk of age) and advanced steatosis, hyperinsulinemia, and hyperglycemia (20 wk of age). In contrast, hepatic p-eNOS/eNOS was significantly lower (P < 0.05) in OLETF rats with T2D advancement and the transition to more advanced NAFLD with inflammation and fibrosis [increased tumor necrosis factor-α (TNF-α), CD68, and CD163 mRNA expression; 40 wk of age]. Reduced hepatic eNOS activation status in 40-wk OLETF rats was significantly correlated with reduced p-Akt/Akt (r = 0.73, P < 0.05), reduced serum insulin (r = 0.59, P < 0.05), and elevated serum glucose (r = -0.78, P < 0.05), suggesting a link between impaired glycemic control and altered hepatic nitric oxide metabolism. VWR by OLETF rats, in conjunction with NAFLD and T2D prevention, normalized p-eNOS/eNOS and p-Akt/Akt to LETO levels. Basal activation of hepatic eNOS and Akt are maintained until advanced NAFLD and T2D development in obese OLETF rats. The prevention of this reduction by VWR may result from maintained insulin sensitivity and glycemic control.

Combining metformin and aerobic exercise training in the treatment of type 2 diabetes and NAFLD in OLETF rats

Here, we sought to compare the efficacy of combining exercise and metformin for the treatment of type 2 diabetes and nonalcoholic fatty liver disease (NAFLD) in hyperphagic, obese, type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. OLETF rats (age: 20 wk, hyperglycemic and hyperinsulinemic; n = 10/group) were randomly assigned to sedentary (O-SED), SED plus metformin (O-SED + M; 300 mg·kg(-1)·day(-1)), moderate-intensity exercise training (O-EndEx; 20 m/min, 60 min/day, 5 days/wk treadmill running), or O-EndEx + M groups for 12 wk. Long-Evans Tokushima Otsuka (L-SED) rats served as nonhyperphagic controls. O-SED + M, O-EndEx, and O-EndEx + M were effective in the management of type 2 diabetes, and all three treatments lowered hepatic steatosis and serum markers of liver injury; however, O-EndEx lowered liver triglyceride content and fasting hyperglycemia more than O-SED + M. In addition, exercise elicited greater improvements compared with metformin alone on postchallenge glycemic control, liver diacylglycerol content, hepatic mitochondrial palmitate oxidation, citrate synthase, and β-HAD activities and in the attenuation of markers of hepatic fatty acid uptake and de novo fatty acid synthesis. Surprisingly, combining metformin and aerobic exercise training offered little added benefit to these outcomes, and in fact, metformin actually blunted exercise-induced increases in complete mitochondrial palmitate oxidation and β-HAD activity. In conclusion, aerobic exercise training was more effective than metformin administration in the management of type 2 diabetes and NAFLD outcomes in obese hyperphagic OLETF rats. Combining therapies offered little additional benefit beyond exercise alone, and findings suggest that metformin potentially impairs exercise-induced hepatic mitochondrial adaptations.

Brain metabolic dysfunction at the core of Alzheimer's disease

Growing evidence supports the concept that Alzheimer's disease (AD) is fundamentally a metabolic disease with molecular and biochemical features that correspond with diabetes mellitus and other peripheral insulin resistance disorders. Brain insulin/IGF resistance and its consequences can readily account for most of the structural and functional abnormalities in AD. However, disease pathogenesis is complicated by the fact that AD can occur as a separate disease process, or arise in association with systemic insulin resistance diseases, including diabetes, obesity, and non-alcoholic fatty liver disease. Whether primary or secondary in origin, brain insulin/IGF resistance initiates a cascade of neurodegeneration that is propagated by metabolic dysfunction, increased oxidative and ER stress, neuro-inflammation, impaired cell survival, and dysregulated lipid metabolism. These injurious processes compromise neuronal and glial functions, reduce neurotransmitter homeostasis, and cause toxic oligomeric pTau and (amyloid beta peptide of amyloid beta precursor protein) AβPP-Aβ fibrils and insoluble aggregates (neurofibrillary tangles and plaques) to accumulate in brain. AD progresses due to: (1) activation of a harmful positive feedback loop that progressively worsens the effects of insulin resistance; and (2) the formation of ROS- and RNS-related lipid, protein, and DNA adducts that permanently damage basic cellular and molecular functions. Epidemiologic data suggest that insulin resistance diseases, including AD, are exposure-related in etiology. Furthermore, experimental and lifestyle trend data suggest chronic low-level nitrosamine exposures are responsible. These concepts offer opportunities to discover and implement new treatments and devise preventive measures to conquer the AD and other insulin resistance disease epidemics.

Metformin prevents hepatic steatosis by regulating the expression of adipose differentiation-related protein

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease, characterized by the excess accumulation of lipids in the liver. It has been demonstrated that the dysregulation of lipid droplet (LD)-associated proteins may be involved in the development of NAFLD. Adipose differentiation-related protein (ADRP), as one of the major LD-associated proteins, is expressed in normal and steatotic livers; however, the exact role of ADRP in the liver remains unknown. Previous studies have indicated that metformin, as an antidiabetic drug, effectively ameliorates NAFLD. However, its cellular and molecular mechanisms of action remain to be elucidated. Therefore, the aim of this study was to determine the role of ADRP in the metformin-mediated regulation of hepatic steatosis. We examined the effects of meformin in vivo and in vitro using ob/ob mice and primary hepatocytes, respectively. Lipid accumulation in the hepatocytes was induced by treatment with oleate. Our results revealed that metformin prevented hepatic steatosis in ob/ob mice and inhibited oleate-induced lipid accumulation in primary hepatocytes. Furthermore, using real-time PCR and western blot analysis, we examined the mRNA and protein expression of ADRP, respectively. We found that metformin significantly decreased the expression levels of ADRP. In addition, to further clarify the role of ADRP in lipid accumulation, we generated recombinant adenoviruses to induce the overexpression of ADRP and to knockdown ADRP. In the hepatocytes in which ADRP was overexpressed, the reducing effects of metformin on lipid accumulation were diminished. However, the knockdown of ADRP using siRNA targeting ADRP reduced the accumulation of triglycerides. Taken together, our data demonstrate that metformin prevents hepatic steatosis by regulating the expression of ADRP, which may be a key target in the treatment of NAFLD.

Cardiorespiratory fitness, waist circumference, and alanine aminotransferase in youth

PURPOSE

Nonalcoholic fatty liver disease (NAFLD) is considered the liver component of the metabolic syndrome and is strongly associated with cardiometabolic diseases. In adults, cardiorespiratory fitness (CRF) is inversely associated with alanine aminotransferase (ALT), a blood biomarker for NAFLD. However, information regarding these associations is scarce for youth. The objective of this study is to examine associations between CRF, waist circumference, and ALT in youth.

METHODS

Data were obtained from youth (n = 2844, 12-19 yr) in the National Health and Nutrition Examination Survey 2001-2004. CRF was dichotomized into youth FITNESSGRAM categories of "low" and "adequate" CRF. Logistic and quantile regression were used for a comprehensive analysis of associations, and variables with previously reported associations with ALT were a priori included in the models.

RESULTS

Results from logistic regression suggested that youth with low CRF had 1.5 times the odds of having an ALT >30 than youth with adequate CRF, although the association was not statistically significant (P = 0.09). However, quantile regression demonstrated that youth with low CRF had statistically significantly higher ALT (+1.04, +1.05, and +2.57 U·L) at the upper end of the ALT distribution (80th, 85th, and 90th percentiles, respectively) than youth with adequate CRF. For every 1-cm increase in waist circumference, the odds of having an ALT >30 increased by 1.06 (P < 0.001), and the strength of this association increased across the ALT distribution.

CONCLUSIONS

Future studies should examine whether interventions to improve CRF can decrease hepatic fat and liver enzyme concentrations in youth with ALT ≥80th percentile or in youth diagnosed with NAFLD.

Fatty liver disease index: a simple screening tool to facilitate diagnosis of nonalcoholic fatty liver disease in the Chinese population

BACKGROUND AND OBJECTIVES

A simple screening tool is needed as an aid to optimize management of nonalcoholic fatty liver disease (NAFLD). The purpose of this study was to design a simple index that could be used to predict the presence of NAFLD.

METHODS

A cross-sectional case-control study design was used for this study with 6,926 subjects who had received health assessments.

RESULTS

Multivariate analysis indicated that body mass index (BMI), triglyceride (TG), alanine aminotransferase (ALT) to aspartate aminotransferase (AST) ratio (ALT/AST ratio), and hyperglycemia (HG) were independent risk factors for NAFLD. These variables were used to construct a fatty liver disease (FLD) index: FLD index = BMI + TG + 3 × (ALT/AST ratio) + 2 × HG (presence of HG, HG = 1; absence of HG, HG = 0). The FLD index had an area under the receiver-operating characteristic (AUROC) curve of 0.819 in the training set and 0.817 in the validation set. Values of the FLD index <28.0 or >37.0 excluded the possibility of NAFLD with sensitivity of 94.9 % or detected NAFLD with specificity of 96.0 %, respectively.

CONCLUSIONS

The FLD index is a simple, efficient NAFLD screening tool for the Chinese population that may be used to select people for further analysis and/or treatment, and/or for lifestyle modification.

Inhibition of adipogenesis in 3T3-L1 cells and suppression of abdominal fat accumulation in high-fat diet-feeding C57BL/6J mice after downregulation of hyaluronic acid

OBJECTIVE

Adipogenesis can be spatially and temporally regulated by extracellular matrix (ECM). We hypothesized that the regulation of hyaluronic acid (HA), a component of the ECM, can affect adipogenesis in fat cells. The effects of HA on adipogenesis were investigated in vitro in 3T3-L1 cells and in vivo in high-fat diet-feeding C57BL/6J mice.

METHODS

We investigated the effects of HA by degradation of pre-existing or synthesized HA and artificial inhibition of HA synthesis in adipogenesis.

RESULTS

In vitro adipogenesis in 3T3-L1 cells was inhibited by treating them with exogenous hyaluronidase (HYAL) and with 4-methylumbelliferone, which inhibited the synthesis of HA in a concentration-dependent manner. In vivo, abdominal fat accumulation in high-fat diet-feeding C57BL/6J mice was suppressed by exogenous HYAL 10(4) IU injections, which was associated with reduction of lipid accumulation in liver and increase of insulin sensitivity.

CONCLUSION

Changes in the ECM such as accumulation of high molecular weight of HA by HAS and degradation of HA by endogenous HYAL were essential for adipogenesis both in vitro and in vivo.

The role of angiotensin II in nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is now considered the most prevalent chronic liver disease, affecting over 30% of the US adult population. NAFLD is strongly linked to insulin resistance and is considered the hepatic manifestation of the metabolic syndrome. Activation of the renin-angiotensin-aldosterone system (RAAS) is known to play a role in the hypertension observed in the metabolic syndrome and also is thought to play a central role in insulin resistance and NAFLD. Angiotensin II (AngII) is considered the primary effector of the physiological outcomes of RAAS signaling, both at the systemic and local tissue level. Herein, we review data describing the potential involvement of AngII-mediated signaling at multiple levels in the development and progression of NAFLD, including increased steatosis, inflammation, insulin resistance, and fibrosis. Additionally, we present recent work on the potential therapeutic benefits of RAAS and angiotensin II signaling inhibition in rodent models and patients with NAFLD.

Association of serum CK18-M65 and -M30 with non-alcoholic fatty liver disease

AIM: To analyze the association of serum CK18-M65 and -M30 with non-alcoholic fatty liver disease (NAFLD) and to discuss the possible mechanisms responsible for the formation of NAFLD.

METHODS: Three hundred and nine patients with NAFLD treated from June 2011 to January 2013 at the First Affiliated Hospital of Xinjiang Medical University were included in this study. Two hundred and ninety healthy people served as normal controls. The average age of all subjects was 44.09 years ± 9.99 years. Questionnaire surveys, physical examination, abdominal ultrasound examination and blood biochemical examination were completed in all subjects. The levels of serum 18-M65 and -M30 were determined using ELISA.

RESULTS: Serum levels of CK18-M30 were significantly higher in the NAFLD group than in the control group in both Uyghur and Han Chinese populations (249.03 ng/L ± 133.58 ng/L vs 142.30 ng/L ± 31.89 ng/L, 244.06 ng/L ± 73.76 ng/L vs 143.16 ng/L ± 93.31 ng/L, both P < 0.05). There were no significant differences in serum levels of CK18-M65 between the NAFLD group and control group in both Uyghur and Han Chinese populations (154.69 ng/L ± 138.07 ng/L vs 160.70 ng/L ± 134.19 ng/L, 222.08 ng/L ± 170.52 ng/L vs 239.52 ng/L ± 196.16 ng/L, both P > 0.05). After adjusting for age, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), neutrophil count, lymphocyte count, hemoglobin concentration, fasting plasma glucose, serum triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL), and low-density lipoprotein (LDL), serum levels of CK18-M30 were still significantly higher in the NAFLD group than in the control group, although no significant difference was noted in serum levels of CK18-M65. Logistic regression analysis showed that serum CK18-M30 level was a risk factor for NAFLD (OR = 1.300, P < 0.01), after adjusting for gender, age, BMI, SBP, DBP, TG, TC, HDL, and LDL.

CONCLUSION: Elevation of serum CK18-M30 levels is closely associated with NAFLD, and is an independent risk factor for NAFLD. Serum levels of CK18-M65 are unrelated to NAFLD.

Resveratrol modulates autophagy and NF-κB activity in a murine model for treating non-alcoholic fatty liver disease

In this study, we aimed to investigate the therapeutic effects and involved mechanisms of resveratrol on an established non-alcoholic fatty liver disease (NAFLD) murine model. Wild-type and autophagic mediator ULK1 heterozygous knockout mice were induced to have NAFLD by high-fat diet for 8weeks. After that, resveratrol treatment was applied with the high-fat diet feeding for another 4weeks. Typical features of NAFLD, including histological changes, fibrosis, insulin resistance, oxidative status, and inflammation were characterized. After-treatment with resveratrol showed ameliorative effects on all measured features of NAFLD, from histology, insulin resistance, glucose tolerance to oxidative stress and inflammation. resveratrol treatment also reduced the activity of nuclear factor-κB (NF-κB) through the restoration of its inhibitor IκBα. Partial inhibition of ULK1 expression impaired the ameliorative effects of resveratrol on hepatic histology, fibrosis, oxidative status, inflammation, and NF-κB activity. In conclusion, resveratrol improved NAFLD-caused hepatic injury partially through regulating autophagic and IκBα-NF-κB pathways.

Selective hepatic insulin resistance in a murine model heterozygous for a mitochondrial trifunctional protein defect

Earlier reports suggest a link between mitochondrial dysfunction and development of hepatic insulin resistance. Here we used a murine model heterozygous (HET) for a mitochondrial trifunctional protein (MTP) gene defect to determine if a primary defect in mitochondrial long-chain fatty acid oxidation disrupts hepatic insulin action. Hyperinsulinemic-euglycemic clamps and signaling studies were performed for assessment of whole-body and hepatic insulin resistance/signaling. In addition, hepatic fatty acid oxidation and hepatic insulin action were assessed in vitro using primary hepatocytes isolated from HET and wildtype (WT) mice. In both hepatic mitochondria and isolated primary hepatocytes, heterozygosity of MTP caused an ∼50% reduction in mitochondrial fatty acid oxidation, a significantly impaired glucose disposal during the insulin clamp, and a markedly lower insulin-stimulated suppression of hepatic glucose production. HET mice also exhibited impaired insulin signaling, with increased hepatic phosphorylation of IRS2 (ser731) and reduced Akt phosphorylation (ser473) in both hepatic tissue and isolated primary hepatocytes. Assessment of insulin-stimulated FOXO1/phospho-FOXO1 protein content and PEPCK/G6Pase messenger RNA (mRNA) expression did not reveal differences between HET and WT mice. However, insulin-induced phosphorylation of GSK3β was significantly blunted in HET mice. Hepatic insulin resistance was associated with an increased methylation status of the catalytic subunit of protein phosphatase 2A (PP2A-C), but was not associated with differences in hepatic diacylglycerol content, activated protein kinase C-ϵ (PKC-ϵ), inhibitor κB kinase β (IKK-β), c-Jun N-terminal kinase (JNK), or phospho-JNK protein contents. Surprisingly, hepatic ceramides were significantly lower in the HET mice compared with WT.

CONCLUSION

A primary defect in mitochondrial fatty acid β-oxidation causes hepatic insulin resistance selective to hepatic glycogen metabolism that is associated with elevated methylated PP2A-C, but independent of other mechanisms commonly considered responsible for insulin resistance. (HEPATOLOGY 2013;).

Serum biomarkers in nonalcoholic steatohepatitis: value for assessing drug effects?

Nonalcoholic steatohepatitis (NASH) is a common chronic liver disease throughout the world. In the USA, approximately 3-5% of the population are affected, and the prevalence of this condition is increasing. NASH is associated with an increased risk of liver-related morbidity, such as cirrhosis and fibrosis, as well as cardiovascular disease, and in spite of several clinical studies investigating putative new drugs, no approved treatment is currently available. This is partly due to the nature of the disease. NASH is a complex, slowly progressing disease, and confirmatory clinical trials have long treatment durations and require invasive end points (a liver biopsy). Such invasive assessments are only accepted in confirmatory trials; clinical studies in the exploratory clinical development phase must rely on noninvasive biomarkers as the primary end point. Experimental and clinical research continues to achieve validation and qualification of biomarkers in NASH, which will hopefully assist the development of new treatments for NASH patients.

Non-alcoholic fatty liver disease as an independent manifestation of the metabolic syndrome: results of a US national survey in three ethnic groups

BACKGROUND AND AIM

The metabolic syndrome (MetS) and each of its components are strongly associated with non-alcoholic fatty liver disease (NAFLD). This has led many investigators to suggest that NAFLD is an independent component of the MetS. We formally tested this hypothesis using confirmatory factor analysis, which allows comparison of different models, with or without including NAFLD as a component of the MetS.

METHODS

We analyzed data from 3846 subjects of the Third National Health and Nutrition Examination Survey (1988-1994). NAFLD was defined by increased liver fat measured by ultrasonography.

RESULTS

MetS by Adult Treatment Panel III criteria was present in 20.5%, and 30.2% had NAFLD, defined as mild, moderate, or severe ultrasonographic steatosis. Using confirmatory factor analysis, a basic model representing the MetS using its currently accepted components (glucose, waist, triglyceride/high-density lipoprotein ratio, and mean arterial pressure) showed excellent goodness-of-fit statistics. Addition of NAFLD to the model as a fifth independent variable decreased model fit, suggesting that NAFLD is not an additional independent component of the MetS. Analysis by ethnicity showed that addition of NAFLD decreased model fit in Whites but resulted in minor improvements in non-Hispanic Blacks and Mexican Americans.

CONCLUSIONS

The MetS is strongly associated with NAFLD. However, we found no evidence that NAFLD is an independent component or manifestation of the MetS. Interestingly, ethnic differences might be important in this relationship and require further study.

Elevated serum uric acid levels are associated with non-alcoholic fatty liver disease independently of metabolic syndrome features in the United States: Liver ultrasound data from the National Health and Nutrition Examination Survey

OBJECTIVE

Experimental and observational studies suggest a role for uric acid in non-alcoholic fatty liver disease (NAFLD). We examined the association between serum uric acid levels and NAFLD in a large population-based study from the United States.

MATERIALS/METHODS

A cross-sectional analysis of 10,732 nondiabetic adults who participated in the National Health and Nutrition Examination Survey 1988-1994. Sex specific uric acid quartiles were defined: ≤5.2, 5.3-6.0, 6.1-6.9, and >6.9mg/dL for men and ≤3.7, 3.8-4.5, 4.6-5.3, and >5.3mg/dL for women. NAFLD presence and severity were defined by ultrasonographic detection of steatosis in the absence of other liver diseases. We modeled the probability that more severe NAFLD would be associated with the highest quartiles of uric acid.

RESULTS

Compared to the 1st quartile, the odds ratio for NAFLD was 1.79 (95% C.I. 1.49-2.15, p<0.001) and 3.14 (95% C.I. 2.63-3.75, p<0.001) for the 3rd and 4th quartiles, respectively. After adjusting for demographics, hypertension, waist circumference, triglycerides, high-density lipoprotein-cholesterol, homeostasis model assessment-estimated insulin resistance, estimated glomerular filtration rate, and aspartate aminotransferase, uric acid (4th quartile) was significantly associated with NAFLD (odds ratio 1.43; 95% C.I. 1.16-1.76, p<0.001). Positive parameter estimates suggest increasing uric acid is associated with greater severity of NAFLD.

CONCLUSIONS

Elevated uric acid level is independently associated with ultrasound-diagnosed NAFLD in a nationally representative sample of United States nondiabetic adults. Increasing uric acid is associated with increasing severity of NAFLD on ultrasonography. These findings warrant further studies on the role of uric acid in NAFLD.

The severity of histologic liver lesions is independent of body mass index in patients with nonalcoholic fatty liver disease

GOALS/BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is associated with obesity, but it may also be present in lean individuals. We evaluated the characteristics of NAFLD patients, focusing on those with normal body mass index (BMI).

STUDY

One hundred and sixty-two of 185 consecutive NAFLD patients were included. Demographic, clinical, somatometric, and laboratory characteristics were recorded. BMI<25 kg/m2 was considered to be normal.

RESULTS

Of the 162 patients, 12% had normal BMI. Patients with normal compared with those with increased BMI fulfilled more frequently no criterion of metabolic syndrome (43% vs. 2%; P<0.001) and had higher median alanine aminotransferase (92 vs. 62 IU/L; P=0.032) and aspartate aminotransferase levels (45 vs. 37 IU/L; P=0.036). Liver stiffness values by transient elastography were significantly lower in patients with normal than in those with increased BMI (5.0 ± 1.6 vs. 9.5 ± 8.7 kPa; P=0.003). In the 56 patients with liver biopsy, the prevalence of nonalcoholic steatohepatitis (50% vs. 68.8%; P=0.423) and the severity of inflammation and fibrosis did not significantly differ between cases with normal and those with increased BMI.

CONCLUSIONS

Approximately 1 of 8 NAFLD patients coming to a Greek tertiary liver center has normal BMI. On liver biopsy, normal BMI patients often have nonalcoholic steatohepatitis and histologic liver lesions of similar severity to the overweight or obese patients.

Increased H-FABP concentrations in nonalcoholic fatty liver disease. Possible marker for subclinical myocardial damage and subclinical atherosclerosis

AIM

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disorder which is reported as the hepatic manifestation of metabolic syndrome with an increased risk of cardiovascular events. Patients with NAFLD are also at risk of future cardiac events independently of metabolic syndrome. The aim of this study was to examine serum concentrations of heart type fatty acid binding protein (H-FABP) in NAFLD and to investigate its correlations with metabolic parameters and subclinical atherosclerosis.

PATIENTS AND METHODS

A total of 34 patients with NAFLD and 35 healthy subjects were enrolled in the study. NAFLD patients had elevated liver enzymes and steatosis graded on ultrasonography. Healthy subjects had normal liver enzymes and no steatosis on ultrasonography. H-FABP levels were measured using an enzyme linked immunosorbent assay (ELISA) method and correlations with metabolic parameters and subclinical atherosclerosis were examined. Subclinical atherosclerosis was determined with carotid artery intima-media thickness (CIMT) which was measured by high resolution B mode ultrasonography.

RESULTS

H-FABP levels were elevated in patients with NAFLD (16.3 ± 4.0 ng/ml) when compared with healthy controls (13.8 ± 2.1 ng/ml; p  < 0.001). NAFLD patients had significantly higher CIMT than the controls had (0.64 ± 0.17 mm vs. 0.43 ± 0.14 mm, p = 0.009). The H-FABP concentrations were significantly positively correlated with body mass index (r = 0.255, p = 0.042), fasting blood glucose level (r = 0.300, p = 0.013), CIMT (r = 0.335, p = 0.043), and homeostasis model assessment-estimated insulin resistance (HOMA-IR; r = 0.156, p = 0.306). In multiple linear regression analysis, H-FABP levels were only independently associated with CIMT (p = 0.04)

CONCLUSION

Serum H-FABP concentrations increase in patients with NAFLD. Our results may not only suggest that H-FABP is a marker of subclinical myocardial damage in patients with NAFLD but also of subclinical atherosclerosis, independent of metabolic syndrome and cardiac risk factors.

Effect of testosterone administration on liver fat in older men with mobility limitation: results from a randomized controlled trial

BACKGROUND

Androgen receptor (AR) knockout male mice display hepatic steatosis, suggesting that AR signaling may regulate hepatic fat. However, the effects of testosterone replacement on hepatic fat in men are unknown. The aim of this study was to determine the effects of testosterone administration on hepatic fat in older men with mobility limitation and low testosterone levels who were participating in a randomized trial (the Testosterone in Older Men trial).

METHODS

Two hundred and nine men with mobility limitation and low total or free testosterone were randomized in the parent trial to either placebo or 10-g testosterone gel daily for 6 months. Hepatic fat was determined by magnetic resonance imaging in 73 men (36 in placebo and 37 in testosterone group) using the volumetric method. Insulin sensitivity (homeostatic model assessment-insulin resistance) was derived from fasting glucose and insulin.

RESULTS

Baseline characteristics were similar between the two groups, including liver volumes (1583 ± 363 in the testosterone group vs 1522 ± 271 mL in the placebo group, p = .42). Testosterone concentrations increased from 250 ± 72 to 632 ± 363 ng/dL in testosterone group but did not change in placebo group. Changes in liver volume during intervention did not differ significantly between groups (p = .5) and were not related to on-treatment testosterone concentrations. The change in homeostatic model assessment-insulin resistance also did not differ significantly between groups and was not related to either baseline or change in liver fat.

CONCLUSION

Testosterone administration in older men with mobility limitation and low testosterone levels was not associated with a reduction in hepatic fat. Larger trials are needed to determine whether testosterone replacement improves liver fat in men with nonalcoholic hepatic steatosis.

Influence of non-alcoholic fatty liver disease on the development of diabetes mellitus

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD) is linked to metabolic syndrome, and is known to be associated with impaired fasting glycemia and diabetes mellitus. This prospective community-based study was conducted to determine the association between NAFLD and incidence of diabetes mellitus in an urban adult population in Sri Lanka.

METHODS

Participants of the Ragama Health Study cohort were assessed for NAFLD using established ultrasound criteria in 2007. Those who were free of diabetes at baseline were followed up for 3 years. Incidence rates of diabetes mellitus were compared between subjects with and without NAFLD at baseline.

RESULTS

Out of 2984 subjects, 926 had NAFLD and 676 had diabetes in 2007. Of the 2276 subjects who were free of diabetes in 2007, 1914 were re-assessed in 2010. After 3 years, 104 out of 528 subjects with NAFLD and 138 out of 1314 subjects without NAFLD had developed diabetes mellitus de novo. Incidence rates of diabetes were respectively 64.2 and 34 per 1000 person-years of follow up for those with and without NAFLD. NAFLD was an independent predictor of developing diabetes mellitus. Other independent predictors were impaired fasting glycemia and dyslipidemia.

CONCLUSIONS

Subjects with ultrasonically diagnosed NAFLD have an increased risk of developing diabetes mellitus. Intervention for NAFLD through lifestyle modification may prevent progression of the current diabetes epidemic.

Altered hepatic lipid metabolism contributes to nonalcoholic fatty liver disease in leptin-deficient Ob/Ob mice

Nonalcoholic fatty liver disease (NAFLD) is strongly linked to obesity, insulin resistance, and abnormal hepatic lipid metabolism; however, the precise regulation of these processes remains poorly understood. Here we examined genes and proteins involved in hepatic oxidation and lipogenesis in 14-week-old leptin-deficient Ob/Ob mice, a commonly studied model of obesity and hepatic steatosis. Obese Ob/Ob mice had increased fasting glucose, insulin, and calculated HOMA-IR as compared with lean wild-type (WT) mice. Ob/Ob mice also had greater liver weights, hepatic triglyceride (TG) content, and markers of de novo lipogenesis, including increased hepatic gene expression and protein content of acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), and stearoyl-CoA desaturase-1 (SCD-1), as well as elevated gene expression of PPARγ and SREBP-1c compared with WT mice. While hepatic mRNA levels for PGC-1α, PPARα, and TFAM were elevated in Ob/Ob mice, measures of mitochondrial function (β-HAD activity and complete (to CO(2)) and total mitochondrial palmitate oxidation) and mitochondrial OXPHOS protein subunits I, III, and V content were significantly reduced compared with WT animals. In summary, reduced hepatic mitochondrial content and function and an upregulation in de novo lipogenesis contribute to obesity-associated NAFLD in the leptin-deficient Ob/Ob mouse.

The effects of chronic AMPK activation on hepatic triglyceride accumulation and glycerol 3-phosphate acyltransferase activity with high fat feeding

BACKGROUND

High fat feeding increases hepatic fat accumulation and is associated with hepatic insulin resistance. AMP Activated Protein Kinase (AMPK) is thought to inhibit lipid synthesis by the acute inhibition of glycerol-3-phosphate acyltransferase (GPAT) activity and transcriptional regulation via sterol regulatory element binding protein-1c (SREBP-1c).

METHODS

The purpose of this study was to determine if chronic activation of AMPK prevented an increase in GPAT1 activity in rats fed a high fat diet. Rats were fed a control (C), or a high fat (HF) diet (60% fat) for 6 weeks and injected with saline or a daily aminoimidazole carboxamide ribnucleotide (AICAR) dose of 0.5 mg/g body weight.

RESULTS

Chronic AMPK activation by AICAR injections resulted in a significant reduction in hepatic triglyceride accumulation in both the C and HF fed animals (C, 5.5±0.7; C+AICAR, 2.7 ±0.3; HF, 21.8±3.3; and HF+AICAR, 8.0±1.8 mg/g liver). HF feeding caused an increase in total GPAT and GPAT1 activity, which was not affected by chronic AMPK activation (GPAT1 activity vs. C, C+AICAR, 92±19%; HF, 186±43%; HF+AICAR, 234±62%). Markers of oxidative capacity, including citrate synthase activity and cytochrome c abundance, were not affected by chronic AICAR treatment. Interestingly, HF feeding caused a significant increase in long chain acyl-CoA dehydrogenase or LCAD (up 66% from C), a marker of fatty acid oxidation capacity.

CONCLUSIONS

These results suggest that chronic AMPK activation limits hepatic triglyceride accumulation independent of a reduction in total GPAT1 activity.

Obesity and colorectal cancer

Obesity is a risk factor for colorectal cancer based on its molecular and metabolic effects on insulin and IGF-1, leptin, adipocytokines, and sex hormones. Obese men have a higher risk of colorectal cancer compared with normal weight men, but the association between obesity and rectal cancer is weaker than with colon cancer. There is a weaker association between obesity and colon cancer in women than in men, and no appreciable association between obesity and rectal cancer in women. Although obesity does not seem to have an effect on the number of lymph nodes harvested with resection, obesity does seem to be associated with more-aggressive colorectal cancers in a handful of studies. Survival and local recurrence studies are contradictory with no conclusive evidence that obesity predisposes to worse overall survival or increased recurrence in colon and rectal cancers. The literature is not definitive as far as overall morbidity and mortality rates in the obese are concerned, though obese rectal cancer patients seem to incur proportionally more morbidity and mortality. Preexisting steatosis or steatohepatitis in obese colorectal cancer patients or chemotherapy-induced liver dysfunction may lead to an increased mortality in obese patients with colorectal liver metastases. Diabetes may cause poorer response to neoadjuvant therapy in rectal cancer and contribute to higher mortality and recurrence in colon cancer.

Clinical update on screening, diagnosis and management of metabolic disorders and cardiovascular risk factors associated with polycystic ovary syndrome

PURPOSE OF REVIEW

Polycystic ovarian syndrome (PCOS) is the most common endocrinopathy in premenopausal women. This review discusses the screening, diagnosis and management of metabolic disorders and cardiovascular risk factors associated with PCOS, highlighting significant recent developments.

RECENT FINDINGS

PCOS is a complex genetic disorder with multiple susceptibility genes as well as environmental factors influencing the expression of various PCOS phenotypes. The first genome-wide association study of PCOS identified susceptibility loci on chromosome 2 near the luteinizing hormone receptor gene LHCGR and chromosome 9 near the obesity gene DEEND1A. Women with PCOS are affected by a variety of metabolic disorders, including insulin resistance, metabolic syndrome, type-2 diabetes, dyslipidemia and obesity. Recently, it has been established that women with PCOS have a high risk of nonalcoholic fatty liver disease. These metabolic disturbances are associated with an increased risk of cardiovascular disease (CVD). Although women with PCOS have higher rates of cardiovascular risk factors and intermediate markers of CVD, studies definitively documenting increased CVD are lacking.

SUMMARY

The high prevalence of metabolic disorders and CVD risk factors in women with PCOS highlights the need for early screening, diagnosis and treatment of these disorders to promote long-term health and possibly prevent CVD.

Non-alcoholic fatty liver disease (NAFLD) is associated with low level of physical activity: a population-based study

BACKGROUND

High intensity exercise improves metabolic status and may potentially mobilise hepatic fat.

AIM

To assess the level of physical activity (PA) of subjects with non-alcoholic fatty liver disease (NAFLD).

METHODS

Data were obtained from NHANES (2003-2006). Activity counts obtained from accelerometer readings (ActiGraph, Fort Walton Beach, FL), from 7 consecutive days quantified total PA and time spent engaged in different levels of activity. All measures were counts/minutes/day: (sedentary <100; light 100-0027; moderate, 2020-5999 and vigorous, 6000+). NAFLD was defined as a fatty liver index >60 (FLI) in the absence of other chronic liver disease. Subjects with NAFLD were compared to controls using stratum-specific Chi-squared and t-tests. Simple linear regression analyses (with Taylor series linearised variance estimation and weighting) were used to determine the association between PA levels and NAFLD. P-values <0.05 were considered significant. Statistical analyses were conducted using sudaan version 10.1 and sas version 9.1.

RESULTS

We included 3056 participants. NAFLD patients were older, had higher BMI, larger waist circumference, higher sum of skinfolds, more likely to have insulin resistance (HOMA > 3.0) and type-2 diabetes (all P-values <0.01). Average PA for NAFLD subjects was about 28.7 counts/minute/day less than controls (P < 0.01). Furthermore, NAFLD subjects spent less time participating in activity at any level (P < 0.01). Subjects with NAFLD and DM were in the lowest quartile of average PA as well as moderate-vigorous PA (P < 0.01).

CONCLUSIONS

Data from this study show that non-alcoholic fatty liver disease patients have low level of physical activity and, when they have diabetes mellitus, they perform at the lowest quartile of physical activity and moderate-vigorous physical activity.

The prevalence of metabolic risk factors among outpatients with diagnosed nonalcoholic fatty liver disease in Lithuania

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease; there is growing evidence that it is a hepatic manifestation of a metabolic syndrome. This study aimed to assess the prevalence of metabolic risk factors among patients with NAFLD.

MATERIAL/METHODS

Outpatients with NAFLD were recruited into the study. Family physicians recorded patients' demographic and anthropometric data, leisure-time physical activity, concomitant diseases, and pharmacological treatment for NAFLD into standardized Case Report Forms.

RESULTS

In total, data on 798 patients were analyzed. Most patients were women and they were older than the men (mean age, 60.2 ± 9.6 vs. 54.5 ± 11.4 years; p<0.05). Metabolic risk factors (obesity, arterial hypertension, dyslipidemia) were highly prevalent in the study patients, and these factors were more prevalent among women. There were no differences in the mean Body Mass Index (BMI), in the proportion of men or women with BMI >30 kg/m2 or central obesity in the 2 age groups (≤ 60 years and >60 years). Hypertension and diabetes were more prevalent among older men and women. Dyslipidemia was more common among older women. The level of leisure-time physical activity was lower in women and in older patients. The most frequently prescribed pharmacological agents were cytoprotective agents, lipid-lowering drugs, and antioxidants.

CONCLUSIONS

Metabolic risk factors were highly prevalent among patients with NAFLD. Obesity, hypertension, and dyslipidemia were more prevalent among women. The differences in the prevalence of hypertension seemed to be influenced by older age of women.

Metabolic syndrome and nonalcoholic fatty liver disease in a Spanish population: influence of the diagnostic criteria used

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) is highly prevalent and it is considered the hepatic component of the metabolic syndrome (MetS). The WHO, the National Cholesterol Education Program (NCEP) and the International Diabetes Federation (IDF) have different criteria to define MetS. The aim of this study was to analyze the association between NAFLD and MetS using the three existing criteria.

METHODS

Cross-sectional, descriptive population-based study derived from a previous study on the prevalence and factors associated with NAFLD in Spain.

RESULTS

A total of 696 individuals [mean age 53 ± 14 years (range 17-83 years)] were included, 59% of whom were women. The prevalence of MetS was 34.2% according to the IDF, 17.7% according to the NCEP and 15.5% according to the WHO. Concordance among the different criteria was between 76 and 87%, with kappa indexes between 0.39 and 0.54. NAFLD was present in 184 individuals according to echographic criteria (prevalence 26.4%). The prevalence of NAFLD among patients with MetS was 43% (IDF), 53% (NCEP) and 64% (WHO). The odds ratio (95% confidence interval) for a logistic regression using NAFLD as a dependent variable varied from 3.44 (2.42-4.88) for IDF to 7.28 (4.68-11.3) for WHO, being 4.28 (2.84-6.43) for NCEP.

CONCLUSION

The MetS is quite frequent in the general population, although its prevalence varies considerably according to the criteria used for its definition. The MetS is associated with NAFLD, with the WHO definition being the best to determine its presence, probably because of the inclusion of insulin resistance as a main component. Unification of criteria is needed to adequately compare the prevalence of MetS and its relationship with NAFLD in different population groups.

Non-cirrhotic portal hypertension in HIV mono-infected patients

BACKGROUND AND AIM

Unexplained liver injury including fibrosis and portal hypertension has rarely been reported among patients with HIV in the absence of co-infection with hepatitis B (HBV) or hepatitis C (HCV). We describe a series of HIV mono-infected patients with evidence of non-cirrhotic portal hypertension.

METHODS

HIV-infected patients with evidence of portal hypertension who were anti-HBV and anti-HCV negative and HBV and HCV RNA polymerase chain reaction (PCR) negative were identified from patients managed by the Victorian statewide HIV referral service located at The Alfred Hospital, Melbourne. Portal hypertension was defined as either radiological or endoscopic evidence of varices, portal vein flow obstruction, or elevated hepatic venous pressure gradient (HPVG).

RESULTS

Five patients were found to have portal hypertension. These patients were male, aged 41 to 65 years, with known duration of HIV infection between 11 to 25 years. All had been treated with antiretroviral therapy, including didanosine. Tests for metabolic, autoimmune, and hereditary causes of liver disease failed to establish an etiology for the liver injury. All had radiological or endoscopic findings of varices, and four patients had radiological features of portal vein obstruction or flow reversal. Only one patient underwent HPVG measurement, which was elevated. Non-invasive fibrosis assessment revealed increased liver stiffness in three (out of four) patients, and no cirrhotic features were found on those who underwent liver biopsy.

CONCLUSIONS

To our knowledge, this is the largest published series of non-cirrhotic portal hypertension in HIV mono-infected patients in Australia. Further research is needed to understand what relationship, if any, HIV or its treatments might have on liver injury over time.

The role of dietary fatty acids in the pathology of metabolic syndrome

Dysfunctional lipid metabolism is a key component in the development of metabolic syndrome, a very frequent condition characterized by dyslipidemia, insulin resistance, abdominal obesity and hypertension, which are related to an elevated risk for type 2 diabetes mellitus. The prevalence of metabolic syndrome is strongly associated with the severity of obesity; its physiopathology is related to both genetics and food intake habits, especially the consumption of a high-caloric, high-fat and high-carbohydrate diet. With the progress of scientific knowledge in the field of nutrigenomics, it was possible to elucidate how the majority of dietary fatty acids influence plasma lipid metabolism and also the genes expression involved in lipolysis and lipogenesis within hepatocytes and adipocytes. The aim of this review is to examine the relevant mechanistic aspects of dietary fatty acids related to blood lipids, adipose tissue metabolism, hepatic fat storage and inflammatory process, all of them closely related to the genesis of metabolic syndrome.

Evaluation of relationship between grading of fatty liver and severity of atherosclerotic finding

PURPOSE

Nonalcoholic fatty liver disease (NAFLD) is a feature of metabolic syndrome and has a high prevalence in the general population.

OBJECTIVE

To determine the severity of atherosclerotic finding in various grade of NAFLD.

MATERIAL AND METHODS

We examined 250 consecutive patients with various grade of NAFLD and 85 control subjects matched for age, gender, to determine carotid intima-media thickness (CIMT) in each groups.

RESULTS

The mean CIMT in patients with G1, G2 and G3 NAFLD were 0.78±0.15 mm, 0.82±0.11mm and 0.85±0.16mm respectively. The differences in CIMT between the various grades of NAFLD were statistically significant (p=0.01).

CONCLUSION

According to our study results the presence of NAFLD; severity of atherosclerosis will be higher parallel with severity of fatty liver infiltration. Therefore, Patients with NAFLD especially high-grade fatty liver may be candidate to be investigated for the presence CAD.

Epidemiological, clinical, and biochemical characteristics of Saudi patients with nonalcoholic fatty liver disease: a hospital-based study

BACKGROUND

The estimated prevalence of nonalcoholic fatty liver disease (NAFLD) in Saudi Arabia is 7% to 10%. Despite the high prevalence of risk factors including diabetes, obesity, and hyperlipidemia, no recent epidemiological studies have measured the disease burden. We aimed to determine the characteristics of Saudi NAFLD patients attending a university hospital, and study factors affecting alanine aminotransferase (ALT) levels.

DESIGN AND SETTING

A prospective study among patients referred for ultrasonography in King Khalid University Hospital in Riyadh, Saudi Arabia from February to May 2009.

PATIENTS AND METHODS

NAFLD was defined as an appearance of fatty liver on routine abdominal ultrasound in the absence of coexisting liver disease and alcohol consumption. Patients were classified into normal and high ALT (ALT >60 U/L) level groups for analysis.

RESULTS

The prevalence of NAFLD was 16.6% (218/1312). Patients with normal ALT had the mean (SD) age of 45.9 (10.6) years and the mean body mass index of 34.5 (7.9) kg/m2. Forty percent of the 151 patients with normal ALT had diabetes, 66.2% were obese, and 29.1% had hypertension. Forty-three patients (23%) had high ALT levels. These patients had significantly lower age (P=.003) and fasting blood sugar (P=.03) than the normal ALT group. Non-diabetic patients (odds ratio 0.30, 95% CI 0.1-0.8), men (female OR 0.23, 95% CI 0.1-0.5), lower cholesterol (P=.001), high-density lipoprotein (P=.006), and low-density lipoprotein (P=.008) levels were more likely to be observed among patients with high ALT levels. In a multivariate analysis, younger age (OR 0.96, 95% CI 0.93-0.99), being male (OR 0.23, 95% CI 0.09-0.57), and a lower cholesterol level (OR 0.55, 95% CI 0.37-0.82) were significant predictors of high ALT levels.

CONCLUSION

Based on the high prevalence of obesity and diabetes, the prevalence of NAFLD will continue to be high, unless awareness is inculcated among the local population.

Kupffer cells ameliorate hepatic insulin resistance induced by high-fat diet rich in monounsaturated fatty acids: the evidence for the involvement of alternatively activated macrophages

BACKGROUND

Resident macrophages (Kupffer cells, KCs) in the liver can undergo both pro- or anti-inflammatory activation pathway and exert either beneficiary or detrimental effects on liver metabolism. Until now, their role in the metabolically dysfunctional state of steatosis remains enigmatic. Aim of our study was to characterize the role of KCs in relation to the onset of hepatic insulin resistance induced by a high-fat (HF) diet rich in monounsaturated fatty acids.

METHODS

Male Wistar rats were fed either standard (SD) or high-fat (HF) diet for 4 weeks. Half of the animals were subjected to the acute GdCl3 treatment 24 and 72 hrs prior to the end of the experiment in order to induce the reduction of KCs population. We determined the effect of HF diet on activation status of liver macrophages and on the changes in hepatic insulin sensitivity and triacylglycerol metabolism imposed by acute KCs depletion by GdCl3.

RESULTS

We found that a HF diet rich in MUFA itself triggers an alternative but not the classical activation program in KCs. In a steatotic, but not in normal liver, a reduction of the KCs population was associated with a decrease of alternative activation and with a shift towards the expression of pro-inflammatory activation markers, with the increased autophagy, elevated lysosomal lipolysis, increased formation of DAG, PKCε activation and marked exacerbation of HF diet-induced hepatic insulin resistance.

CONCLUSIONS

We propose that in the presence of a high MUFA content the population of alternatively activated resident liver macrophages may mediate beneficial effects on liver insulin sensitivity and alleviate the metabolic disturbances imposed by HF diet feeding and steatosis. Our data indicate that macrophage polarization towards an alternative state might be a useful strategy for treating type 2 diabetes.

Gluco-lipidic indices in treated hypothyroidism associated with nonalcoholic fatty liver disease

CONTEXT

Thyroid hormones may interfere with regulation of lipid and carbohydrate metabolism as well as with severity of nonalcoholic fatty liver disease (NAFLD), however results are still debated.

OBJECTIVES

Retrospective evaluation of clinical and metabolic correlations between hypothyroidism and NAFLD was the target.

METHODS

Clinical, biochemical and histological investigation of 103 NAFLD patients exhibiting drug-treated hypothyroidism was conducted.

RESULTS

Steatosis was present in 32.0% of the population and nonalcoholic steatohepatitis in 68.0%. Females were the majority in both groups, with age of 50.0 ± 1.5 and 56.0 ± 1.1 years, respectively. Hypothyroidism was not rare (15.5%), and multivariate analysis confirmed positive correlation with this disease for insulin (r = 0.213, P = 0.03), glucose homeostasis index "HOMA" (r = 0.221, P = 0.02), aspartate aminotransferase (r = 0.234, P = 0.01) and triglycerides above 150 mg/dL (r = 0.233, P = 0.01). No association between hypothyroidism and steatohepatitis could be established.

CONCLUSION

A link could be identified between hypothyroidism and markers of glucose and lipid homeostasis, but not with severity of NAFLD. The lack of correlation with liver biopsy requires further studies.

HIV and hepatitis C co-infection: the role of HAART in HIV/hepatitis C virus management

PURPOSE OF REVIEW

Highly active antiretroviral therapy (HAART)-related hepatotoxicity, a relevant side effect in HIV/hepatitis C virus (HCV) co-infected patients, has evolved over time. Antiretroviral therapy might have a positive effect on the liver of HIV/HCV co-infected patients, but data are conflicting.

RECENT FINDINGS

HIV treatments have evolved and we have currently a drug armamentarium with a good liver safety profile. Most of the current first-line HAART regimens recommended by guidelines fit well to HIV/HCV co-infected patients. There are now multiple retrospective studies that suggest a possible benefit of HIV control and protection of CD4 cell counts to the liver of HIV/HCV co-infected patients. However, data are conflicting at times. This factor along with the methodological limitations of these studies prevent us from drawing definitive conclusions. Even assuming a positive effect, HAART does not appear to fully correct the adverse effect of HIV infection on HCV-related outcomes. In the era of HCV direct antiviral agents, the timing of HIV and HCV therapies has to be individualized in HIV/HCV co-infected patients given the variety of scenarios.

SUMMARY

With current HIV drug armamentarium it is possible to construct HAART regimens with optimal liver safety profile for HCV co-infected patients. The possible positive effect of HAART on the HCV-infected liver should not distract from the main intervention, which is HCV eradication with specific treatment.

Non-alcoholic fatty liver disease may develop in individuals with normal body mass index

BACKGROUND

Although non-alcoholic fatty liver disease (NAFLD) is associated with obesity and metabolic syndrome (MS), it may also be present in lean individuals. We evaluated the characteristics of NAFLD patients, focusing on those with normal body mass index (BMI).

METHODS

One hundred and sixty-two of 185 consecutive NAFLD patients were included (23 were excluded due to missing data). NAFLD diagnosis required elevated ALT and/or GGT, hepatic steatosis on ultrasonography and no other cause of liver disease. Demographic, clinical, somatometric and laboratory characteristics were recorded. BMI <25 kg/m2 was considered normal.

RESULTS

Normal BMI was present in 12% of patients. Patients with normal compared to those with increased BMI had numerically but not significantly lower prevalence of diabetes mellitus (6% vs. 15%, p=0.472), arterial hypertension (17% vs. 29%, p=0.276) and MS (20% vs. 41%, p=0.160). Normal BMI NAFLD patients met no criterion of MS more frequently (43% vs. 2%, p<0.0001) and had smaller waist circumference (94±6 vs. 108±10 cm, p<0.001), higher median levels of ALT (92 vs. 62 IU/L, p=0.032) and AST (45 vs. 37 IU/L, p=0.036) and relatively lower fasting glucose levels (98±22 vs. 106±29 mg/dL, p=0.052), but similar levels of HDL, LDL and triglycerides.

CONCLUSION

Approximately 1 of 8 NAFLD patients coming to the tertiary liver center has normal BMI. These patients do not necessarily have insulin resistance associated metabolic disorders, but they have higher levels of ALT/AST than the overweight or obese NAFLD patients.

Inhibitory effect of blueberry polyphenolic compounds on oleic acid-induced hepatic steatosis in vitro

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide and is closely associated with metabolic syndromes, such as obesity, diabetes, and insulin resistance. Nonalcoholic fatty liver (NAFL), also called simple steatosis, is the initial phase of NAFLD, which is accompanied the characteristic pathological overaccumulation of lipids without inflammation. To prevent NAFLD from reaching the NAFL stage through dietary therapy, in the present work, wild Chinese blueberries (Vacciniun spp.) were selected for their well-known benefits in inhibiting metabolic syndrome. After being purified from wild Chinese blueberries, polyphenol-rich extracts were subsequently separated into three fractions, namely, anthocyanin-rich fraction, phenolic acid-rich fraction, and ethyl acetate extract. The inhibition of oleic acid (OA)-induced triglyceride (TG) deposition in HepG 2 cells was referred to as the potential activity of preventing NAFL. Biochemical indicators, such as cytotoxicity, TG level, levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and intracellular reactive oxygen species, were used to evaluate the analogous pathological stage of NAFLD. The results show that OA ≤ 1.0 mM exhibits a dose-dependent induction of TG accumulation, and no inflammation was observed based on the changes in ALT and AST levels. Therefore, 1.0 mM OA was used to simulate an in vitro fatty liver. Blueberry polyphenol-rich extract efficiently inhibited OA-induced TG accumulation in HepG2 cells, and the phenolic acid-rich fraction performed efficiently. Seven phenolic acids were subsequently identified using a high-performance liquid chromatography assay, and the main types were caffeic, chlorogenic, ferulic, p-coumaric, and cinnamic acids. These phenolic acid standards also displayed good efficiency in inhibiting TG accumulation in HepG2 cells. These results imply that wild Chinese blueberries have a potential preventive effect on NAFLD in its early stage, and phenolic acids are the most efficient component.

The effect of cocoa supplementation on hepatic steatosis, reactive oxygen species and LFABP in a rat model of NASH

Background

Non alcoholic steatohepatitis is hypothesised to develop via a mechanism involving fat accumulation and oxidative stress. The current study aimed to investigate if an increase in oxidative stress was associated with changes in the expression of liver fatty acid binding protein in a rat model of non alcoholic steatohepatitis and whether cocoa supplementation attenuated those changes.

Methods

Female Sprague Dawley rats were fed a high fat control diet, a high fat methionine choline deficient diet, or one of four 12.5% cocoa supplementation regimes in combination with the high fat methionine choline deficient diet.

Results

Liver fatty acid binding protein mRNA and protein levels were reduced in the liver of animals with fatty liver disease when compared to controls. Increased hepatic fat content was accompanied by higher levels of oxidative stress in animals with fatty liver disease when compared to controls. An inverse association was found between the levels of hepatic liver fatty acid binding protein and the level of hepatic oxidative stress in fatty liver disease. Elevated NADPH oxidase protein levels were detected in the liver of animals with increased severity in inflammation and fibrosis. Cocoa supplementation was associated with partial attenuation of these pathological changes, although the severity of liver disease induced by the methionine choline deficient diet prevented complete reversal of any disease associated changes. Red blood cell glutathione was increased by cocoa supplementation, whereas liver glutathione was reduced by cocoa compared to methionine choline deficient diet fed animals.

Conclusion

These findings suggest a potential role for liver fatty acid binding protein and NADPH oxidase in the development of non alcoholic steatohepatitis. Furthermore, cocoa supplementation may have be of therapeutic benefit in less sever forms of NASH.

Evaluation of atherosclerotic findings in patients with nonalcoholic fatty liver disease

Background

Nonalcoholic fatty liver disease (NAFLD), a highly prevalent condition, is a feature of metabolic syndrome and is characterized by excessive accumulation of fat in the liver cells. The purpose of this study was to investigate the association between NAFLD and carotid intima-media thickness (CIMT) as an independent risk factor for atherosclerosis.

Methods

We examined 250 consecutive patients with ultrasonographically confirmed NAFLD and 85 age-matched and gender-matched controls with normal parenchymal liver echogenicity for determination of CIMT and presence of carotid atherosclerotic plaque.

Results

Compared with control subjects, patients with NAFLD showed an increased mean CIMT (0.81 ± 0.14 mm) compared with control subjects (0.58 ± 0.15 mm). This difference was statistically significant (P = 0.001). After performing multivariate analysis, the presence of NAFLD was associated with abnormal CIMT independent of other atherogenic risk factors or its association with metabolic syndrome.

Conclusion

NAFLD can be an independent risk factor for developing atherosclerosis. Therefore, NAFLD with and without metabolic syndrome can be associated with increased CIMT and increased risk of cardiovascular events in patients with NAFLD incidentally diagnosed on abdominal ultrasonography.

Centrizonal arteries and microvessels in nonalcoholic steatohepatitis

Correct classification of nonalcoholic steatohepatitis (NASH) liver biopsies is of critical importance and relies on correct orientation to microscopic liver architecture. Centrizonal arteries can cause central zones to be mistaken for portal tracts, especially in the setting of centrizonal ductular reaction, and result in either missed diagnosis or inaccurate staging of NASH. A total of 100 randomly selected biopsies from NASH Clinical Research Network participants (February 2005 to August 2006, fibrosis stage >1a) were evaluated for arteries and CD34-positive microvessels in the centrizonal region. Prevalence of both centrizonal arteries and CD34-positive microvessels was graded as 0 (none in central zones), 1 (1 to 2 central zones with vessels), 2 (<50% of central zones with vessels), or 3 (≥50% of central zones with vessels). Centrizonal arteries and CD34-positive microvessels were present in 40 and 100 cases (40% and 100%), respectively. Arteries and CD34-positive microvessels were more commonly found in central zones in biopsies with greater degrees of fibrosis (62% with arteries in stage 3 to 4 versus 21% in stage 1 to 2 and 70% with microvessels in stage 3 to 4 versus 25% in stage 1 to 2), with increased prevalence of both centrizonal arteries and CD34-positive microvessels correlating directly with fibrosis stage (P<0.001). Ductular reaction was a common finding (55%) in patients with central zone arteries. The presence of centrizonal arteries must be recognized to allow for correct orientation to liver architecture in NASH and, together with the finding of increased CD34-positive microvessel formation in higher-stage fibrosis, suggests a possible association between neoangiogenesis and NASH progression to cirrhosis.