Review article: the metabolic syndrome and non-alcoholic fatty liver disease

Insights from exploring the interrelated dynamics of gallstone disease, non-alcoholic fatty liver disease, and kidney stone disease

This article delved into the comprehensive study by Jiang et al, which meticulously examined the bidirectional relationships among gallstone disease, non-alcoholic fatty liver disease, and kidney stone disease through a multicenter study, systematic review, and meta-analysis. The study provides significant evidence supporting these associations, offering valuable insights into the etiology and potential prevention strategies for these interconnected conditions. The clinical significance of these bidirectional relationships is profound, as they underscore the importance of recognizing these conditions not only as isolated diseases but as part of a complex network that can influence each other. These results highlight the critical need for thorough screening and personalized prevention strategies for individuals with these interconnected conditions. Explicit implications for prevention strategies and early screening practices are crucial, as they can lead to early detection and intervention, significantly altering disease progression and outcomes. Furthermore, identifying potential therapeutic targets within these shared pathways may enhance treatment efficacy and patient outcomes, making this research highly relevant to clinical practice. By comprehending the common pathophysiological mechanisms and applying specific interventions, healthcare professionals can greatly enhance patient care and lessen the impact of these widespread diseases on global health.

Endothelial Dysfunction in Obesity and Therapeutic Targets

Parallel to the increasing prevalence of obesity in the world, the mortality from cardiovascular disease has also increased. Low-grade chronic inflammation in obesity disrupts vascular homeostasis, and the dysregulation of adipocyte-derived endocrine and paracrine effects contributes to endothelial dysfunction. Besides the adipose tissue inflammation, decreased nitric oxide (NO)-bioavailability, insulin resistance (IR), and oxidized low-density lipoproteins (oxLDLs) are the main factors contributing to endothelial dysfunction in obesity and the development of cardiorenal metabolic syndrome. While normal healthy perivascular adipose tissue (PVAT) ensures the dilation of blood vessels, obesity-associated PVAT leads to a change in the profile of the released adipo-cytokines, resulting in a decreased vasorelaxing effect. Higher stiffness parameter β, increased oxidative stress, upregulation of pro-inflammatory cytokines, and nicotinamide adenine dinucleotide phosphate (NADP) oxidase in PVAT turn the macrophages into pro-atherogenic phenotypes by oxLDL-induced adipocyte-derived exosome-macrophage crosstalk and contribute to the endothelial dysfunction. In clinical practice, carotid ultrasound, higher leptin levels correlate with irisin over-secretion by human visceral and subcutaneous adipose tissues, and remnant cholesterol (RC) levels predict atherosclerotic disease in obesity. As a novel therapeutic strategy for cardiovascular protection, liraglutide improves vascular dysfunction by modulating a cyclic adenosine monophosphate (cAMP)-independent protein kinase A (PKA)-AMP-activated protein kinase (AMPK) pathway in PVAT in obese individuals. Because the renin-angiotensin-aldosterone system (RAAS) activity, hyperinsulinemia, and the resultant IR play key roles in the progression of cardiovascular disease in obesity, RAAS-targeted therapies contribute to improving endothelial dysfunction. By contrast, arginase reciprocally inhibits NO formation and promotes oxidative stress. Thus, targeting arginase activity as a key mediator in endothelial dysfunction has therapeutic potential in obesity-related vascular comorbidities. Obesity-related endothelial dysfunction plays a pivotal role in the progression of type 2 diabetes (T2D). The peroxisome proliferator-activated receptor gamma (PPARγ) agonist, rosiglitazone (thiazolidinedione), is a popular drug for treating diabetes; however, it leads to increased cardiovascular risk. Selective sodium-glucose co-transporter-2 (SGLT-2) inhibitor empagliflozin (EMPA) significantly improves endothelial dysfunction and mortality occurring through redox-dependent mechanisms. Although endothelial dysfunction and oxidative stress are alleviated by either metformin or EMPA, currently used drugs to treat obesity-related diabetes neither possess the same anti-inflammatory potential nor simultaneously target endothelial cell dysfunction and obesity equally. While therapeutic interventions with glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide or bariatric surgery reverse regenerative cell exhaustion, support vascular repair mechanisms, and improve cardiometabolic risk in individuals with T2D and obesity, the GLP-1 analog exendin-4 attenuates endothelial endoplasmic reticulum stress.

Betel Nut Chewing Increases the Risk of Metabolic Syndrome and Its Components in a Large Taiwanese Population Follow-Up Study Category: Original Investigation

Betel nut chewing is a popular habit in Taiwan, and it is associated with adverse metabolic effects. The aim of this study was to investigate correlations between betel nut chewing with metabolic syndrome (MetS) and its components in a longitudinal study using data from the Taiwan Biobank. A total of 121,423 participants were included in the baseline study, and 27,002 received follow-up examinations after a median of 4 years. The association between betel nut chewing and MetS was analyzed using multiple logistic regression after controlling for confounders. The baseline prevalence of MetS was 22.5%. Multivariable analysis showed that a history of chewing betel nut was significantly associated with baseline MetS (odds ratio (OR) = 1.629; 95% confidence interval (CI) = 1.535 to 1.730, p < 0.001) and five components of MetS in all participants. A long history of chewing betel nut (per 1 year; OR = 1.008; 95% CI = 1.004 to 1.013, p < 0.001) was associated with baseline MetS, abdominal obesity, hypertriglyceridemia and low high-density lipoprotein (HDL) cholesterol. In addition, high cumulative dose (per 1 year × frequency × daily score; OR = 1.001; 95% CI = 1.001−1.002; p < 0.001) was significantly associated with baseline MetS. At the end of the follow-up, a history of chewing betel nut (OR = 1.352; 95% CI = 1.134 to 1.612, p = 0.001) was significantly associated with MetS and its components including abdominal obesity, hypertriglyceridemia and low HDL-cholesterol in the participants without baseline MetS. In addition, a longer history of betel nut chewing was associated with MetS (per 1 year; OR = 1.021; 95% CI = 1.008 to 1.035, p = 0.002), abdominal obesity and hypertriglyceridemia at follow-up. However, cumulative dose (p = 0.882) was not significantly associated with follow-up MetS. Chewing betel nut and a long history of betel nut chewing were associated with baseline MetS and its components. In the participants without MetS at baseline, chewing betel nut and a long history of chewing betel nut were associated with the development of MetS after 4 years of follow-up. However, a cumulative dose of betel nut chewing was not associated with follow-up MetS. Betel nut chewing cessation programs are important to reduce the incidence of MetS in Taiwan.

Significant burden of nonalcoholic fatty liver disease with advanced fibrosis in the US: a cross-sectional analysis of 2011-2014 National Health and Nutrition Examination Survey

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease in the US. Understanding the epidemiology of NAFLD, with specific focus on individuals with hepatic fibrosis is important to guide healthcare resource planning.

AIM

To evaluate prevalence and predictors of hepatic fibrosis among US adults with NAFLD.

METHODS

We performed a cross-sectional study using data from the updated 2011-2014 National Health and Nutrition Examination Survey, a national, stratified, multistage sampling survey of non-institutionalised US adults age ≥ 20. METAVIR F2 or greater fibrosis among individuals with NAFLD was assessed using AST to Platelet Ratio Index (APRI) score > 0.7. METAVIR F3 or greater fibrosis was assessed using NAFLD fibrosis score (NFS) > 0.676 and FIB-4 score > 3.25. Multivariate logistic regression models evaluated for predictors of fibrosis among individuals with NAFLD.

RESULTS

Overall prevalence of NAFLD among US adults was 21.9% (95% CI 20.6-23.3), representing 51.6 million adults. Among individuals with NAFLD, we observed a 23.8% prevalence of ≥F2 fibrosis, representing 12.2 million individuals, and we observed a 2.3%-9.7% prevalence of ≥F3 fibrosis, representing as many as 5.0 million adults. On multivariate regression analyses, increasing age, obesity and concurrent diabetes mellitus were associated with increased risk of ≥F3 fibrosis.

CONCLUSIONS

NAFLD represents a major healthcare burden among US adults with as many as 5 million adults estimated to have NAFLD with ≥F3 fibrosis. Age and the components of the metabolic syndrome are independently associated with higher risk of fibrosis.

The Reliability of Classification of Terminal Nodes in GUIDE Decision Tree to Predict the Nonalcoholic Fatty Liver Disease

Tree structured modeling is a data mining technique used to recursively partition a dataset into relatively homogeneous subgroups in order to make more accurate predictions on generated classes. One of the classification tree induction algorithms, GUIDE, is a nonparametric method with suitable accuracy and low bias selection, which is used for predicting binary classes based on many predictors. In this tree, evaluating the accuracy of predicted classes (terminal nodes) is clinically of special importance. For this purpose, we used GUIDE classification tree in two statuses of equal and unequal misclassification cost in order to predict nonalcoholic fatty liver disease (NAFLD), considering 30 predictors. Then, to evaluate the accuracy of predicted classes by using bootstrap method, first the classification reliability in which individuals are assigned to a unique class and next the prediction probability reliability as support for that are considered.

Endothelial Dysfunction in Obesity

Chronic inflammatory state in obesity causes dysregulation of the endocrine and paracrine actions of adipocyte-derived factors, which disrupt vascular homeostasis and contribute to endothelial vasodilator dysfunction and subsequent hypertension. While normal healthy perivascular adipose tissue (PVAT) ensures the dilation of blood vessels, obesity-associated PVAT leads to a change in profile of the released adipo-cytokines, resulting in a decreased vasorelaxing effect. Adipose tissue inflammation, nitric oxide (NO)-bioavailability, insulin resistance and oxidized low-density lipoprotein (oxLDL) are main participating factors in endothelial dysfunction of obesity. In this chapter, disruption of inter-endothelial junctions between endothelial cells, significant increase in the production of reactive oxygen species (ROS), inflammation mediators, which are originated from inflamed endothelial cells, the balance between NO synthesis and ROS , insulin signaling and NO production, and decrease in L-arginine/endogenous asymmetric dimethyl-L-arginine (ADMA) ratio are discussed in connection with endothelial dysfunction in obesity.

Angiotensin-(1-7) improves non-alcoholic steatohepatitis through an adiponectin-independent mechanism

AIM

Recent evidence suggests that angiotensin-(1-7) [Ang-(1-7)] could improve non-alcoholic steatohepatitis (NASH) through an adiponectin-dependent mechanism. This study aimed to investigate whether and how Ang-(1-7) influences NASH without adiponectin.

METHODS

Adiponectin knockout mice were fed with a high fat diet (HFD) or normal chow for 6 months, and were subsequently infused with Ang-(1-7) or saline for 2 weeks.

RESULTS

We found that HFD-fed mice showed obesity, hyperlipidemia, NASH, and significantly increased levels of serum Ang-(1-7). Chronic infusion of Ang-(1-7) could reduce body weight, absolute and relative liver weight, and serum levels of total cholesterol, triglyceride, and low-density lipoprotein cholesterol in HFD-fed mice. In addition, Ang-(1-7) treatment could attenuate hepatocellular inflammation, steatosis, and ballooning with activation of the hepatic AMP-activated protein kinase signaling pathway in HFD-fed knockout mice.

CONCLUSIONS

These results showed the protective role of Ang-(1-7) in the development of NASH through an adiponectin-independent mechanism, which may be partially attributed to the activation of hepatic AMP-activated protein kinase pathway.

Increased parenchymal damage and steatohepatitis in Caucasian non-alcoholic fatty liver disease patients with common IL1B and IL6 polymorphisms

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a complex, multifactorial disease affected by diet, lifestyle and genetics. Proinflammatory cytokines like IL-1β and IL-6 have been shown to be elevated in non-alcoholic steatohepatitis (NASH).

AIM

To investigate the relationship between IL1B and IL6 gene polymorphisms and histological features of NAFLD in the NASH CRN cohort.

METHODS

A total of 604 adult (≥18 years) non-Hispanic Caucasians with biopsy-proven NAFLD were genotyped for the following SNPs: IL1B, rs16944, rs1143634; IL6, rs1800795, rs10499563. Logistic regression was used to examine the relationship between genotype and a definitive diagnosis and advanced histological features of NASH after controlling for the following variables selected a priori: age, sex, diabetes, obesity and HOMA-IR level.

RESULTS

The IL6 rs10499563 C allele was independently associated with the presence of definitive NASH, and increased ballooning and Mallory bodies. The IL1B rs1143634 TT genotype was associated with advanced fibrosis and increased Mallory bodies. The IL6 rs1800795 C allele was associated with not only increased risk for severe steatosis, >66% but also decreased risk for advanced fibrosis and lobular inflammation and Mallory body formation.

CONCLUSIONS

These results suggest that common variants in the IL6 and IL1B genes may increase susceptibility for NASH and confer a higher risk of hepatic parenchymal damage including increased ballooning, increased Mallory bodies, and bridging fibrosis or cirrhosis. In contrast, the IL6 rs1800795 C allele may confer a higher risk for steatosis, but less parenchymal damage. Our findings support the development of therapeutics aimed at IL-1β and IL-6 suppression.

Prediction and Diagnosis of Non-Alcoholic Fatty Liver Disease (NAFLD) and Identification of Its Associated Factors Using the Classification Tree Method

Background

Non-alcoholic fatty liver disease (NAFLD) is the most common form of liver disease in many parts of the world.

Objectives

The aim of the present study was to identify the most important factors influencing NAFLD using a classification tree (CT) to predict the probability of NAFLD.

Patients and Methods

This cross-sectional study was conducted in Kavar, a town in the south of Fars province, Iran. A total of 1,600 individuals were selected for the study via the stratified method and multiple-stage cluster random sampling. A total of 30 demographic and clinical variables were measured for each individual. Participants were divided into two datasets: testing and training. We used the training dataset (1,120 individuals) to build the CT and the testing dataset (480 individuals) to assess the CT. The CT was also used to estimate class and to predict fatty liver occurrence.

Results

NAFLD was diagnosed in 22% of the individuals in the sample. Our findings revealed that the following variables, based on univariate analysis, had a significant association with NAFLD: marital status, history of hepatitis B vaccine, history of surgery, body mass index (BMI), waist-hip ratio (WHR), systolic blood pressure (SBP), diastolic blood pressure (DBP), high-density lipoprotein (HDL), triglycerides (TG), alanine aminotransferase (ALT), cholesterol (CHO0, aspartate aminotransferase (AST), glucose (GLU), albumin (AL), and age (P < 0.05). The main affecting variables for predicting NAFLD based on the CT and in order of importance were as follows: BMI, WHR, triglycerides, glucose, SBP, and alanine aminotransferase. The goodness of fit model based on the training and testing datasets were as follows: prediction accuracy (80%, 75%), sensitivity (74%, 73%), specificity (83%, 77%), and the area under the receiver operating characteristic (ROC) curve (78%, 75%), respectively.

Conclusions

The CT is a suitable and easy-to-interpret approach for decision-making and predicting NAFLD.

Prevention of cardiac dysfunction, kidney fibrosis and lipid metabolic alterations in l-NAME hypertensive rats by sinapic acid--Role of HMG-CoA reductase

The present study was designed to evaluate the effect of sinapic acid, a bioactive phenolic acid on high blood pressure associated cardiac dysfunction, kidney fibrosis and lipid alterations in N(ω)-nitro-l-arginine methyl ester hydrochloride (l-NAME) induced hypertensive rats. Sinapic acid was administered to rats orally at a dosage of 40 mg/kg everyday for a period of 4 weeks. Sinapic acid treatment significantly decreased mean arterial pressure, left ventricular end diastolic pressure, organ weights (liver and kidney), lipid peroxidation products in tissues (liver and kidney), activities of hepatic marker enzymes and the levels of renal function markers in serum of l-NAME rats. Sinapic acid treatment also significantly increased the level of plasma nitric oxide metabolites, and enzymatic and non-enzymatic antioxidants in tissues of l-NAME rats. Tissue damage was assessed by histopathological examination. Alterations in plasma angiotensin-converting enzyme activity, level of plasma lipoproteins and tissue lipids were corrected by sinapic acid treatment in l-NAME rats. Sinapic acid treatment significantly decreased the activity of 3-hydroxy-3-methylglutaryl-Coenzyme A (HMG-CoA) reductase in plasma and liver, whereas the activity of lecithin cholesterol acyl transferase was significantly increased in the plasma of hypertensive rats. Docking result showed the interaction between sinapic acid and HMG-CoA reductase. Sinapic acid has shown best ligand binding energy of -5.5 kcal/M. Moreover, in chick embryo model, sinapic acid improved vessel density on chorioallantoic membrane. These results of the present study concludes that sinapic acid acts as a protective agent against hypertension associated cardiac dysfunction, kidney fibrosis and lipid alterations.

Metalloproteinases and leptin in vehicle drivers of public service with metabolic syndrome in Armenia, Quindío

OBJECTIVE

To describe the relationship between metalloproteinase (MMP) 2, MMP-9, and leptin in drivers of public service vehicles with metabolic syndrome in the city of Armenia (Quindio, Colombia).

METHODS

Leptin was measured using Millipore ELISA kits. MMP-2 and MMP-9 were measured with ELISA kits from R&D Systems.

RESULTS

Fifty-seven male drivers with metabolic syndrome with a mean age of 45.35years, BMI of 29.81, and an abdominal circumference of 105.75cm were identified. Blood pressure values were 126.5/82.5mmHg. Leptin, MMP-2, and MMP-9 levels were 24.6ng/mL, 28,1ng/mL, and 7.5ng/mL respectively. The relationship between leptin and waist circumference was statistically significant (P<.001). The explained variation (R(2)) in waist circumference, is explained in a 80.12% for the study variables, has a statistically significant association with BMI (P<.001), MMP-2 (P=.01), age (P=.01), SBP (P<.001) and DBP (P<.001). The R(2) of leptin, is explained in a 69.56% for the study variables, has a statistically significant association with BMI (P<.001), MMP-2 (P=.05) and triglycerides (P=.02). The R(2) of MMP-2, explained in 41.82% of the study variables and has a statistically significant association with waist circumference (P=.01), glucose (P=.01) and age (P=.03).

CONCLUSIONS

Statistically significant associations were found between waist circumference and MMP-2; leptin and MMP-2, and MMP-2 and waist circumference and blood glucose.

Serum Chemerin Levels in relation to Osteoporosis and Bone Mineral Density: A Case-Control Study

BACKGROUND

To evaluate serum chemerin levels in patients with osteoporosis and healthy controls and to investigate the relationship between serum chemerin levels and bone mineral density (BMD).

METHODS

An age- and gender-matched case-control study was conducted. Pearson's correlation test was performed to investigate the relationship between serum chemerin levels and BMD.

RESULTS

There were 93 patients included in the osteoporosis group and 93 matched controls. Serum chemerin level was significantly higher in patients with osteoporosis (87.27 ± 5.80 ng/mL) than patients in control (71.13 ± 5.12 ng/mL) (P < 0.01). There was a negative correlation between femoral bone mineral density and chemerin in both groups (R = -0.395, P < 0.01 in osteoporosis group; R = -0.680, P < 0.01 in control) and also a negative correlation between lumbar bone mineral density with chemerin in both groups (R = -0.306, P < 0.01 in osteoporosis group; R = -0.362, P < 0.01 in control).

CONCLUSIONS

Patients with osteoporosis presented a higher level of serum chemerin, which witnessed an inverse correlation with BMD. Further studies are needed to explore the role of chemerin in the pathophysiology of osteoporosis.

Role of diet on non-alcoholic fatty liver disease: An updated narrative review

The purpose of this article review is to update what is known about the role of diet on non-alcoholic fatty liver disease (NAFLD). NAFLD is the most common cause of chronic liver disease in the developed world and is considered to be a spectrum, ranging from fatty infiltration of the liver alone (steatosis), which may lead to fatty infiltration with inflammation known as non alcoholic steatohepatitis While the majority of individuals with risk factors like obesity and insulin resistance have steatosis, only few people may develop steatohepatitis. Current treatment relies on weight loss and exercise, although various insulin-sensitizing medications appear promising. Weight loss alone by dietary changes has been shown to lead to histological improvement in fatty liver making nutrition therapy to become a cornerstone of treatment for NAFLD. Supplementation of vitamin E, C and omega 3 fatty acids are under consideration with some conflicting data. Moreover, research has been showed that saturated fat, trans-fatty acid, carbohydrate, and simple sugars (fructose and sucrose) may play significant role in the intrahepatic fat accumulation. However, true associations with specific nutrients yet to be clarified.

Valproic acid prevents the deregulation of lipid metabolism and renal renin-angiotensin system in L-NAME induced nitric oxide deficient hypertensive rats

The present study was aimed to investigate the antihyperlipidemic and renoprotective potential of valproic acid against N(ω)-nitro-L arginine methyl ester hydrochloride (L-NAME) induced hypertension in male albino Wistar rats. In hypertensive rats, mean arterial pressure (MAP), kidney weight, levels of oxidative stress markers in tissues were increased. Dyslipidemia was also observed in hypertensive rats. Moreover, enzymatic and nonenzymatic antioxidant network also deregulated in tissues. Valproic acid (VPA) supplementation daily for four weeks brought back all the above parameters to near normal level and showed no toxicity which was established using serum hepatic marker enzyme activities and renal function markers. Moreover the up regulated expression of renin-angiotensin system (RAS) components were also attenuated by VPA treatment. All the above outcomes were confirmed by the histopathological examination. These results suggest that VPA has enough potential to attenuate hypertension, dyslipidemia and renal damage in nitric oxide deficiency induced hypertension.

Hepatic glucose intolerance precedes hepatic steatosis in the male aromatase knockout (ArKO) mouse

Estrogens are known to play a role in modulating metabolic processes within the body. The Aromatase knockout (ArKO) mice have been shown to harbor factors of Metabolic syndrome with central adiposity, hyperinsulinemia and male-specific hepatic steatosis. To determine the effects of estrogen ablation and subsequent replacement in males on whole body glucose metabolism, three- and six-month-old male ArKO mice were subjected to whole body glucose, insulin and pyruvate tolerance tests and analyzed for ensuing metabolic changes in liver, adipose tissue, and skeletal muscle. Estrogen-deficient male ArKO mice showed increased gonadal adiposity which was significantly reduced upon 17β-estradiol (E2) treatment. Concurrently, elevated ArKO serum leptin levels were significantly reduced upon E2 treatment and lowered serum adiponectin levels were restored to wild type levels. Three-month-old male ArKO mice were hyperglycemic, and both glucose and pyruvate intolerant. These phenotypes continued through to 6 months of age, highlighting a loss of glycemic control. ArKO livers displayed changes in gluconeogenic enzyme expression, and in insulin signaling pathways upon E2 treatment. Liver triglycerides were increased in the ArKO males only after 6 months of age, which could be reversed by E2 treatment. No differences were observed in insulin-stimulated ex vivo muscle glucose uptake nor changes in ArKO adipose tissue and muscle insulin signaling pathways. Therefore, we conclude that male ArKO mice develop hepatic glucose intolerance by the age of 3 months which precedes the sex-specific development of hepatic steatosis. This can be reversed upon the administration of exogenous E2.

The role of antioxidants and other agents in alleviating hyperglycemia mediated oxidative stress and injury in liver

Several antioxidants and agents having similar antioxidant effects are known to exert beneficial effects in ameliorating the injurious effects of hyperglycemia on liver in different diabetic in vitro and in vivo models. The review deals with some of the agents which have been shown to exert protective effects on liver against hyperglycemic insult and the various mechanisms involved. The different classes of agents which protect the diabetic liver or decrease the severity of hyperglycemia mediated injury include flavonoids, catechins, and other polyphenolic compounds, curcumin and its derivatives, certain vitamins, hormones and drugs, trace elements, prototypical antioxidants and amino acids. Some of the pronounced changes mediated by the antioxidants in liver exposed to hyperglycemia include decreased oxidative stress, and alterations in carbohydrate and lipid metabolism. Other mechanisms through which the agents ameliorate hyperglycemia mediated liver injury include decrease in oxidative DNA and protein damage, restoration of mitochondrial structural and functional integrity, decrease in inflammation and improved insulin signaling. Thus, antioxidants may prove to be an important mode of defense in maintaining normal hepatic functions in diabetes.

Non alcoholic fatty liver disease in southern Iran: a population based study

BACKGROUND

Population based studies on prevalence and risk factors of NAFLD in Iranian population are few. The prevalence of NAFLD and non alcoholic steatohepatitis (NASH) in Iranians varies from 2.9% to 7.1% in general population and 55.8% in patients with type 2 diabetes mellitus.

OBJECTIVES

To determine the prevalence and determinants of non alcoholic fatty liver disease (NAFLD) in a sample of adult Iranian general population.

PATIENTS AND METHODS

This was a cross-sectional study being performed in Shiraz, southern Iran during a 10-month period from November 2010 to September 2011 through cluster random sampling of Iranian general population in Shiraz region. All individuals undergone anthropometric, blood pressure measurements, thorough medical history and physical examinations. Laboratory measurements included fasting blood glucose (FBS), lipid profile, complete blood count (CBC) and liver function tests. NAFLD was diagnosed by transabdominal ultrasonography.

RESULTS

819 subjects were included in this study among which were 340 males (41.5%) and 479 females (58.5%) with the mean age of 43.1 ± 14.1 years. NAFLD was diagnosed in 176 (21.5%) subjects. Patients with NAFLD were significantly older (P < 0.001), had higher proportion of male gender (P = 0.004) and had higher BMI (P < 0.001). They also had higher prevalence of hypertension (P < 0.001), high FBS (P < 0.001), high cholesterol (P = 0.026), high triglyceride (P < 0.001) and high waist circumference (P < 0.001). Taking all these together, patients with NAFLD had significantly higher prevalence of metabolic syndrome when compared to healthy subjects (P < 0.001).

CONCLUSION

The prevalence of NAFLD in this group of Iranian adult general population is 21.5%. NAFLD in Iranian population is associated with male gender, old age, obesity, and features of metabolic syndrome.

The GH/IGF-1 Axis in Obesity: Physiological and Pathological Aspects

The cluster of cardiovascular risk factors-abdominal obesity, dyslipidaemia, insulin resistance and hypertension-has been recognized as the core of the metabolic syndrome. Adults with severe growth hormone (GH) deficiency have, to a large extent, features of the metabolic syndrome, and there is a strong inverse association between visceral fat accumulation and blunted GH secretion in adults. Hyposomatotropism in abdominal obesity has therefore been suggested to be of importance for its metabolic consequences. However, the underlying pathophysiological mechanisms are poorly understood. Prevalence of the metabolic syndrome is steadily increasing worldwide. Overnutrition and sedentary habits are the stigmata of modern society that predispose genetically susceptible individuals to develop central obesity and other features of the metabolic syndrome including glucose intolerance, hypertension and dyslipidemia. Although there are still no unified definitions of the syndrome, it is clear that this condition is associated with an increased risk for development of cardiovascular disease (CVD) and diabetes mellitus (DM). In this review, we discuss current evidence regarding alterations in the GH-IGF- 1 axis in abdominal obesity and its possible impact on other features of the metabolic syndrome.

Investigation of anthropometric, biochemical and dietary parameters of obese children with and without non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) in children has been recognized as a major health burden. The high prevalence of NAFLD is probably due to the contemporary epidemics of obesity, unhealthy dietary pattern, and sedentary lifestyle. The purpose of this study was to investigate anthropometric, biochemical and dietary intake parameters of obese Greek children with and without NAFLD. Eighty two obese children aged 8-15 (45 boys/37 girls) participated in the study. Ultrasonography (US) was used to diagnose NAFLD in all participated subjects. Liver indexes were measured in all children. A 3-day dietary was recorded for all subjects. Data for continuous variables is expressed as mean values±standard deviation. Thirty-five out of eighty two subjects (42.6%) had NAFLD. Body Mass Index levels (P<0.001) and Waist Circumference (P<0.046) levels were statistically higher in the children with severe NAFLD (37.2kg/m(2)±6.2 and 102.9cm±14) compared to children with mild NAFLD (26.6kg/m(2)±3.3 and 86.1cm±9.9) and absent of fatty liver (25.3kg/m(2)±3.6 and 85.2cm±11.2), respectively. Total carbohydrates intakes were significantly higher in subjects with NAFLD (288.8g±70.6) compared to children without NAFLD (244.5g±67.5), (P<0.001). Saturated fatty acids (SFAs) intake was proportionally increased to the degree of hepatic steatosis, while n-3 fatty acids (n-3 FA) consumption was inversely related with NAFLD. In multiple regression analysis of factors associated with NAFLD, HOMA-IR (OR: 1.260, 95%CI: 1.110-1.470, P<0.001) and n-3FA (OR:1.921, 95%CI:1.132-2.187, P<0.001) were the most significant ones. Our results showed that IR, high dietary intakes of CHO and SFA and a low dietary consumption of fiber and n-3 FA were positively associated with the pathogenesis of NAFLD.

Dietary Coleus forskohlii extract generates dose-related hepatotoxicity in mice

Coleus forskohlii root extract (CFE) represented by its bioactive constituent 'forskolin' is popularly used as a natural weight-lowering product, but the association of its use with liver-related risks is very limited. In the present study, the effect of standardized CFE with 10% forskolin on liver function of mice was examined. Mice were given 0-5% CFE in an AIN93G-based diet for 3-5 weeks. Food intake, body weights, relative organ weights and liver marker enzymes [aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP)] combined with histophatological analysis were assessed. CFE (0-0.5%) only had minimal effects on food intake and body weight whereas a significant difference was observed in mice receiving the highest dose (5% CFE). The extract 0.05-5% dose-dependently decreased visceral fat weight by between 16% and 63%, and a dose-dependent several folds increase was observed in liver weights and plasma AST, ALT and ALP activities with quick onset apparent after only 1 week of 0.5% CFE intake. The hepatic effect persisted throughout the 3-weeks course but was restored towards normalization within 1 week after withdrawal of treatment. Liver histology of mice fed 0.5% CFE for 3 weeks showed hepatocyte hypertrophy and fat deposition. In contrast, none of the hepatic responses measured were altered when mice were given a diet containing pure forskolin alone at the dose corresponding to its content in 0.5% CFE. The present study clearly indicated that forskolin was not involved in the CFE-induced hepatotoxicity and was caused by other unidentified constituents in CFE which warrants further studies.

Antihypertensive and antioxidant potential of vanillic acid, a phenolic compound in L-NAME-induced hypertensive rats: a dose-dependence study

We investigated the antihypertensive and antioxidant potential of vanillic acid (VA) in N(ω)-Nitro-L-arginine methyl ester hydrochloride (L-NAME) - treated adult male albino Wistar rats. Treatment of rats with L-NAME (40 mg/kg Bw for 30 days) caused a sustained increase in systolic- (SBP) and diastolic blood pressure (DBP) and significantly decreased the concentration of nitrite/nitrate (NO(x)) in plasma as compared with that in the control. Rats treated with VA restored SBP and DBP to normal level and preserve the plasma NO metabolites concentration. Moreover, VA reduced lipid peroxidation products (thiobarbituric acid reactive substances, lipid hydroperoxides, conjugated dienes) and significantly restored enzymatic antioxidants (superoxide dismutase, catalase, and glutathione peroxidase), non-enzymatic antioxidants (vitamin C, vitamin E, and reduced glutathione) in the plasma. To assess the toxicity if any of VA treatment, hepatic and renal function markers were measured. Our results showed that the effect at a dose of 50 mg/kg Bw of VA was more pronounced than that of the other two doses, 25 and 100 mg/kg Bw. These results were supported by histopathology studies. We conclude that VA possesses an antihypertensive and antioxidant activity in L-NAME-induced hypertensive rats.

Carbohydrate but not fat is associated with elevated aminotransferases

BACKGROUND

Recently, many studies reported that high carbohydrate and simple sugar intake increase a risk of obesity and metabolic syndrome significantly.

AIM

To investigate the effect of carbohydrate on aminotransferase levels in Korea, where the proportion of carbohydrate in meals is extremely high but fat is low.

METHODS

We used the data of Korean National Health and Nutrition Examination Surveys (KNHANES). A total of 19 749 people were included. Amounts and types of consumed foods were examined by the 24 h recall method.

RESULTS

Mean carbohydrate and fat proportions in total energy intake were 67.7% and 17.4%, respectively. Aminotransferase activity increased according to the rise of the proportion of carbohydrate in the energy intake. A high carbohydrate intake (>70% of energy) was associated with abnormal aminotransferase activity and metabolic syndrome. After adjusting for covariates, such as age, energy intake and body mass index, abnormal aminotransferase activity was significantly associated with carbohydrate proportion. There was a negative correlation between fat proportion in the total energy intake and aminotransferase activity (P < 0.01). The relation between aminotransferase activity and carbohydrate composition showed a J-shaped curve. The lowest point (the J point) was located at 50-60% carbohydrate.

CONCLUSIONS

The proportion of carbohydrate in energy intake but not fat is positively correlated with abnormal aminotransferase activity in Koreans. This finding may be useful in planning a strategy of nutrition education for NAFLD in countries where the proportion of carbohydrate in most meals is extremely high.

Etiopathogenesis of nonalcoholic steatohepatitis: role of obesity, insulin resistance and mechanisms of hepatotoxicity

Incidence of nonalcoholic fatty liver disease is increasing with an estimated prevalence of 20-30% in developed nations. This is leading to increased incidence of chronic liver disease, cirrhosis, and hepatocellular cancer. It is critical to understand the etiology and pathogenesis of any disease to create therapeutic targets and develop new treatments. In this paper we discuss the etiology and pathogenesis of nonalcoholic steatohepatitis with special focus on obesity, role of insulin resistance, and molecular mechanisms of hepatotoxicity.

Treatment of atherogenic liver based on the pathogenesis of nonalcoholic fatty liver disease: a novel approach to reduce cardiovascular risk?

Nonalcoholic fatty liver disease (NAFLD), which spans a spectrum of conditions ranging from simple steatosis to progressive nonalcoholic steatohepatitis (NASH), is the most common chronic liver disease and a relevant public health issue. The prevalence of NAFLD depends on adiposity, age, gender and ethnicity. The natural history of liver disease in those with NAFLD critically depends on liver histological changes. However, cardiovascular mortality is increased in NAFLD, particularly in middle-aged adults. Against such a background, this review consists of three sections. First, data on NAFLD as a novel mechanism of increased cardiovascular risk via hyperinsulinism, pro-thrombotic potential, and subclinical inflammation are summarized. Next, the role of atherogenic liver in the development of manifestations of oxidative stress and atherosclerosis is emphasized. Finally, whether and how treating NAFLD will mechanistically result in reduced cardiovascular risk through ameliorated metabolic syndrome is discussed.

Systematic review and meta-analysis on the adverse events of rimonabant treatment: considerations for its potential use in hepatology

Background

The cannabinoid-1 receptor blockers have been proposed in the management of obesity and obesity-related liver diseases (fatty liver as NAFLD or NASH). Due to increasing number of patients to be potentially treated and the need to assess the advantage of this treatment in terms of risk/benefit, we analyze the side events reported during the treatment with rimonabant by a systematic review and meta-analysis of all randomized controlled studies.

Methods

All published randomized controlled trials using rimonabant versus placebo in adult subjects were retrieved. Relative risks (RR) with 95% confidence interval for relevant adverse events and number needed to harm was calculated.

Results

Nine trials (n = 9635) were considered. Rimonabant 20 mg was associated with an increased risk of adverse event (RR 1.35; 95%CI 1.17-1.56), increased discontinuation rate (RR 1.79; 95%CI 1.35-2.38), psychiatric (RR 2.35; 95%CI 1.66-3.34), and nervous system adverse events (RR 2.35; 95%CI 1.49-3.70). The number needed to harm for psychiatric adverse events is 30.

Conclusion

Rimonabant is associated with an increased risk of adverse events. Despite of an increasing interest for its use on fatty liver, the security profile and efficacy it is needs to be carefully assessed before its recommendation. At present the use of rimonabant on fatty liver cannot be recommended.

Statins in liver disease: a molehill, an iceberg, or neither?

A growing number of chronic liver disease patients, especially those with metabolic syndrome-associated nonalcoholic fatty liver disease or hepatitis C virus-associated dysmetabolic syndrome, will take statins to prevent cardiovascular disease. As a result, clinicians will weigh complex issues raised by the interaction of statins with liver metabolism in these disorders. In this article, we critically review data concerning statins and liver pathophysiology with an emphasis on nonalcoholic fatty liver disease and hepatitis C virus, while also touching on other chronic liver diseases. Basic research interests include statins' mechanism of action and their effects on cholesterol-related cell signaling pathways and angiogenesis. From the clinical standpoint, many chronic liver diseases increase cardiovascular risk and would undeniably benefit from sustained statin use. The false alarms and security accompanying aminotransferase monitoring, however, are disturbing in light of the scarcity of data on statins' long-term effects on liver histology. Although some actions of statins might eventually prove to be particularly useful in nonalcoholic steatohepatitis, hepatitis C virus, or hepatocellular carcinoma, others may prove harmful. The lack of definitive data makes a fully informed decision impossible. Research using histological endpoints is urgently needed to determine the indications and contraindications of this extraordinary class of agents in patients with chronic liver disease.

Dysmetabolic changes associated with HCV: a distinct syndrome?

Although not associated with the metabolic syndrome, HCV is linked with impaired insulin signalling, insulin resistance, hypocholesterolemia and steatosis which represent a distinct HCV-associated dysmetabolic syndrome. Insulin resistance affects the development of diabetes, fibrosis, impaired response to antivirals and perhaps hepatocellular carcinoma risk. HCV infection is associated with hypocholesterolemia and steatosis reversible after sustained virologic response. A "viral", and a "metabolic" steatosis exist as function of viral genotypes. Little is known about the possible role of HCV in further components of the metabolic syndrome such as atherosclerosis, obesity, arterial hypertension, hyperuricemia and thrombotic risk factors.

Steatohepatitis: Risk factors and impact on disease severity in human immunodeficiency virus/hepatitis C virus coinfection

Hepatic steatosis has been reported in human immunodeficiency virus (HIV)/hepatitis C virus (HCV) coinfection. However, the features of steatohepatitis, including cytologic ballooning and pericellular fibrosis, its risk factors, and the impact on disease severity in such patients are unknown. To assess this, we prospectively reviewed liver histology in consecutive coinfected patients to define the prevalence and severity of the features of steatohepatitis, its risk factors, and its impact on the severity of liver disease. A total of 222 subjects (74% male, mean age 45, 78% African American, 90% genotype 1) were studied. The mean body mass index (BMI) was 26, and 18% had a BMI >30. The prevalence of risk factors for steatosis were: diabetes (31%), hypertension (15%), dyslipidemia (8%), metabolic syndrome (9%), and alcohol abuse (21%). Steatosis was present in 23% and steatohepatitis was present in 17%. The steatosis was mild (5%-33%) in 19%, and moderate to severe (>33%) in 4%. Cytologic ballooning and pericellular fibrosis were present in 30% and 13%, respectively. The mean Ishak score was 6.9, and 33% had bridging fibrosis or cirrhosis. Both steatosis and cytologic ballooning were associated with BMI, metabolic syndrome, and insulin resistance, and presence of either was strongly associated with advanced fibrosis (P < 0.0001). By multiple logistic regressions, the following associations were identified: increased BMI, diabetes, and genotype 3 with steatosis; diabetes with cytologic ballooning; and longer duration of infection with steatohepatitis.

CONCLUSION

Steatosis and steatohepatitis are present in 23% and 30%, respectively, of patients with HIV/HCV coinfection, and both are associated with an increased risk of having advanced fibrosis. Although we did identify genotype 3, increased BMI, and diabetes as risk factors, we found no independent association with antiretroviral therapy.

Weight loss, dietary advice and statin therapy in non-alcoholic fatty liver disease: a retrospective study

BACKGROUND

Studies have shown that weight loss can have a favourable effect upon non-alcoholic fatty liver disease (NAFLD). However, the most effective means of achieving weight loss and safety profile of lipid-lowering drugs in the presence of NAFLD is unknown.

AIM

To investigate the effect of dietary advice and lipid-lowering drugs, particularly statins, on patients with NAFLD and dyslipidaemia.

DESIGN

Observational records based study.

METHODS

We studied 71 patients with NAFLD and dyslipidaemia diagnosed and treated between 1996 and 2002 at University Hospital Lewisham. Some were referred to a dietician for weight loss advice as part of their management. After treatment all patients were assessed for changes in weight, serum alanine transaminase (ALT) and serum lipids including serum cholesterol, serum high density lipoprotein (HDL) and serum triglycerides.

RESULTS

Thirty-seven male and 34 female patients with NAFLD and dyslipidaemia were followed up for a mean period of 440 +/- 374 days (median 335). Regression analysis revealed a significant association between changes in weight and changes in serum ALT (p < 0.039). Dietary advice failed to reduce body weight but significantly lowered the serum cholesterol to HDL ratio (p = 0.05). Only 15.4% of patients taking statins experienced a rise in serum ALT > or = 40 U/l, and in each case the rise was transient, returning near baseline or below without discontinuation of statin treatment.

CONCLUSIONS

Weight loss appears to improve NAFLD, and dietary advice and lipid-lowering drugs may be beneficial for patients with NAFLD and dyslipidaemia even if weight loss is not achieved. Statins appear to be safe and efficacious in this group.

Treating nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a chronic illness with multiple consequences. The spectrum of disease ranges from simple steatosis, with benign prognosis, to a potentially progressive form, nonalcoholic steatohepatitis, which may lead to liver fibrosis and cirrhosis, leading to an increase in morbidity and mortality. Furthermore, hepatocellular carcinoma incidence in NAFLD is comparable with that observed in hepatitis C-infected patients once cirrhosis is established. Current therapy is limited to lifestyle changes and control of associated metabolic disorders; however, new treatments are on the way from basic research to bedside. A review of the current literature on treatment of nonalcoholic fatty liver disease is presented in this article.

Update on non-alcoholic fatty liver disease in children

Non-alcoholic fatty liver disease (NAFLD) is probably the most common cause of liver disease in the pediatric community. It is closely associated with obesity and insulin resistance. NAFLD may lead to non-alcoholic steatohepatitis (NASH). Although NASH is a prerequisite for the definition of NAFLD in adults and children, distinct differences are often apparent in the extent or location of fat, inflammation and fibrosis. Confirmation of the diagnosis of NAFLD can usually be achieved by imaging studies; however, staging the disease requires a liver biopsy. Current treatment relies on weight loss and exercise, although various insulin-sensitizing agents, antioxidants and medications appear promising. The aim of this review is to summarize what is known about pediatric NAFLD in terms of prevalence, pathogenesis, diagnosis, histology and treatment.

Adeno-associated virus LPL(S447X) gene therapy in LDL receptor knockout mice

BACKGROUND

Overexpression of lipoprotein lipase (LPL) protects against atherosclerosis in genetically engineered mice. We tested whether a gene therapy vector that delivers human (h) LPL(S447X) cDNA to skeletal muscle could induce similar effects.

METHODS

LDL receptor knockout (LDLr-/-) mice were injected intramuscular (i.m.) with adeno-associated virus serotype 1 (AAV1) LPL(S447X) or PBS. Four weeks later they were started on an atherogenic diet for 12 weeks. After termination, atherosclerosis was assessed and homogenates of muscle and liver tissue were analyzed.

RESULTS

AAV1-treated mice showed hLPL concentrations of 768+/-293 ng/mL in post-heparin plasma associated with 48% reductions of fasting triglycerides (TG) levels (p<0.0001). In the absence of an effect on total cholesterol (TC) levels, no effects on atherosclerosis were found. An increase in lipid content of injected muscles was accompanied by a significant decrease of TG (-20%, p<0.0001) and free cholesterol (FC) content (-24%, p<0.0001) in liver homogenates.

CONCLUSIONS

The data show that transgenic hLPL(S447X) on top of endogenous murine LPL reduces fasting TG levels in plasma but has no effect on atherosclerosis in LDLr-/- mice. While lipid accumulation in the injected muscle was anticipated, this coincided with an interesting decrease of both TG and FC in liver homogenates.