Adipokines and cytokines in non-alcoholic fatty liver disease

Increased Serum Levels of LIGHT/TNFSF14 in Nonalcoholic Fatty Liver Disease: Possible Role in Hepatic Inflammation

OBJECTIVES

The tumor necrosis factor superfamily member 14, LIGHT (homologous to lymphotoxin, exhibits inducible expression, and competes with HSV glycoprotein D for herpes virus entry mediator (HVEM), a receptor expressed by T lymphocytes), has been involved in various autoimmune disorders and has been shown to influence hepatic lipid metabolism. We hypothesized that LIGHT could also have a pathogenic role in nonalcoholic fatty liver disease (NAFLD).

METHODS

Serum levels of LIGHT in NAFLD patients and control subjects, as well as LIGHT and interleukin (IL)-8 released from Huh7 (human hepatoma cell line) hepatocytes, were determined by enzyme-linked immunosorbent assay. The mRNA expression of LIGHT in the liver tissue and mRNA levels of LIGHT and IL-8 in Huh7 hepatocytes were assessed by real-time quantitative reverse transcription-PCR.

RESULTS

(i) Serum levels of LIGHT were significantly elevated in NAFLD patients (n=66) as compared with healthy controls (n=16), with no differences between simple steatosis (n=34) and nonalcoholic steatohepatitis (NASH) (n=32). (ii) Within the liver, NAFLD patients (n=14) had significantly increased mRNA levels of the two LIGHT receptors, herpes virus entry mediator and lymphotoxin β receptor (LTβR), as compared with controls (n=7), with no difference between simple steatosis (n=8) and NASH (n=6). (iii) LIGHT markedly increased the release of IL-8 in Huh7 hepatocytes in a time- and dose-dependent manner. (iv) The reactive oxygen species (ROS) H2O2 (hydrogen peroxide) enhanced the LIGHT-mediated release of IL-8 in Huh7 hepatocytes.

CONCLUSION

We show increased levels of LIGHT and its two membrane-bound receptors in NAFLD, potentially promoting hepatic inflammation through ROS interaction. Our findings should encourage further studies on the role of LIGHT in NAFLD development and progression.

LUBAC Formation Is Impaired in the Livers of Mice with MCD-Dependent Nonalcoholic Steatohepatitis

Nonalcoholic steatohepatitis (NASH) is a disorder characterized by hepatic lipid accumulation followed by the inflammation-induced death of hepatocytes and fibrosis. In this process, oxidative stress contributes to the induction of several inflammatory cytokines including TNF-α andIL-1β in macrophages, while, in hepatocytes, NF-κB reportedly induces the expressions of cell survival genes for protection from apoptosis. Recently, it was reported that the new ubiquitin ligase complex termed linear ubiquitin chain assembly complex (LUBAC), composed of SHARPIN (SHANK-associated RH domain-interacting protein), HOIL-1L (longer isoform of heme-oxidized iron-regulatory protein 2 ubiquitin ligase-1), and HOIP (HOIL-1L interacting protein), forms linear ubiquitin on NF-κB essential modulator (NEMO) and thereby induces NF-κB pathway activation. In this study, we demonstrated the formation of LUBAC to be impaired in the livers of NASH rodent models produced by methionine and choline deficient (MCD) diet feeding, first by either gel filtration or Blue Native-PAGE, with subsequent confirmation by western blotting. The reduction of LUBAC is likely to be attributable to markedly reduced expression of SHARPIN, one of its components. Thus, impaired LUBAC formation, which would result in insufficient NF-κB activation, may be one of the molecular mechanisms underlying the enhanced apoptotic response of hepatocytes in MCD diet-induced NASH livers.

The Riddle of Nonalcoholic Fatty Liver Disease: Progression From Nonalcoholic Fatty Liver to Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver (NAFL) is an emerging global epidemic which progresses to nonalcoholic steatohepatitis (NASH) and cirrhosis in a subset of subjects. Various reviews have focused on the etiology, epidemiology, pathogenesis and treatment of NAFLD. This review highlights specifically the triggers implicated in disease progression from NAFL to NASH. The integrating role of genes, dietary factors, innate immunity, cytokines and gut microbiome have been discussed.

Dihydromyricetin improves glucose and lipid metabolism and exerts anti-inflammatory effects in nonalcoholic fatty liver disease: A randomized controlled trial

Ampelopsis grossedentata, a medicinal and edible plant, has been widely used in China for hundreds of years, and dihydromyricetin is the main active ingredient responsible for its various biological actions. We investigated the effects of dihydromyricetin on glucose and lipid metabolism, inflammatory mediators and several biomarkers in nonalcoholic fatty liver disease. In a double-blind clinical trial, sixty adult nonalcoholic fatty liver disease patients were randomly assigned to receive either two dihydromyricetin or two placebo capsules (150 mg) twice daily for three months. The serum levels of alanine, aspartate aminotransferase, γ-glutamyl transpeptidase, glucose, low-density lipoprotein-cholesterol and apolipoprotein B, and the homeostasis model assessment of insulin resistance (HOMA-IR) index were significantly decreased in the dihydromyricetin group compared with the placebo group. In the dihydromyricetin group, the serum levels of tumor necrosis factor-alpha, cytokeratin-18 fragment and fibroblast growth factor 21 were decreased, whereas the levels of serum adiponectin were increased at the end of the study. We conclude that dihydromyricetin supplementation improves glucose and lipid metabolism as well as various biochemical parameters in patients with nonalcoholic fatty liver disease, and the therapeutic effects of dihydromyricetin are likely attributable to improved insulin resistance and decreases in the serum levels of tumor necrosis factor-alpha, cytokeratin-18, and fibroblast growth factor 21.

Composite prognostic models across the non-alcoholic fatty liver disease spectrum: Clinical application in developing countries

Heterogeneity in clinical presentation, histological severity, prognosis and therapeutic outcomes characteristic of non-alcoholic fatty liver disease (NAFLD) necessitates the development of scientifically sound classification schemes to assist clinicians in stratifying patients into meaningful prognostic subgroups. The need for replacement of invasive liver biopsies as the standard method whereby NAFLD is diagnosed, graded and staged with biomarkers of histological severity injury led to the development of composite prognostic models as potentially viable surrogate alternatives. In the present article, we review existing scoring systems used to (1) confirm the presence of undiagnosed hepatosteatosis; (2) distinguish between simple steatosis and NASH; and (3) predict advanced hepatic fibrosis, with particular emphasis on the role of NAFLD as an independent cardio-metabolic risk factor. In addition, the incorporation of functional genomic markers and application of emerging imaging technologies are discussed as a means to improve the diagnostic accuracy and predictive performance of promising composite models found to be most appropriate for widespread clinical adoption.

The hop constituent xanthohumol exhibits hepatoprotective effects and inhibits the activation of hepatic stellate cells at different levels

Xanthohumol is the principal prenylated flavonoid of the female inflorescences of the hop plant. In recent years, various beneficial xanthohumol effects including anti-inflammatory, antioxidant, hypoglycemic activities, and anticancer effects have been revealed. This review summarizes present studies indicating that xanthohumol also inhibits several critical pathophysiological steps during the development and course of chronic liver disease, including the activation and pro-fibrogenic genotype of hepatic stellate cells. Also the various mechanism of action and molecular targets of the beneficial xanthohumol effects will be described. Furthermore, the potential use of xanthohumol or a xanthohumol-enriched hop extract as therapeutic agent to combat the progression of chronic liver disease will be discussed. It is notable that in addition to its hepatoprotective effects, xanthohumol also holds promise as a therapeutic agent for treating obesity, dysregulation of glucose metabolism and other components of the metabolic syndrome including hepatic steatosis. Thus, therapeutic xanthohumol application appears as a promising strategy, particularly in obese patients, to inhibit the development as well as the progression of non-alcoholic fatty liver disease.

The relationship between visfatin, liver inflammation, and acute phase reactants in chronic viral hepatitis B

Chronic viral hepatitis B (CHB) is an important cause of morbidity and mortality. Adipokine stimulation might play an important role in the pathogenesis of chronic inflammation. The aim of this study was to evaluate serum visfatin concentrations and the relationship between visfatin, fibrosis, liver inflammation, and acute phase reactants in CHB patients.The sampling universe of the study consisted of 41 CHB patients and 25 healthy controls. All patients had positive hepatitis B surface antigen (Hepatitis e antigen (HBeAg) positive n: 7, n: 34 HBeAg negative) for at least 6 months and detectable serum HBV DNA. Serum visfatin concentrations were significantly higher in the CHB patients [18.0 ± 10.9 ng dL(-1)] than in the healthy controls [9.4 ± 1.6 ng dL(-1)] [P < 0.001]. On the other hand, fibrinogen and haptoglobin concentrations were significantly lower in CHB patients. A strong negative correlation was observed between serum visfatin concentration, haptoglobin, and fibrinogen levels; however, there was no significant correlation between visfatin, glucose, alanine aminotransferase, aspartate aminotransferase, BMI, Knodell score, fibrosis score, hepatitis B virus DNA, sedimentation, and C-reactive protein. Visfatin concentrations were elevated and visfatin was negatively correlated with haptoglobin and fibrinogen levels in CHB patients.

Antiresistin RNA Oligonucleotide Ameliorates Diet-Induced Nonalcoholic Fatty Liver Disease in Mice through Attenuating Proinflammatory Cytokines

The aim of this study was to determine whether inhibition of resistin by a synthetic antiresistin RNA (oligonucleotide) oligo ameliorates metabolic and histological abnormalities in nonalcoholic fatty liver disease (NAFLD) induced by high-fat diet (HFD) in mice. The antiresistin RNA oligo and a scrambled control oligo (25 mg/kg of body weight) were i.p. injected to HFD mice. Serum metabolic parameters and hepatic enzymes were measured after 4-week treatment. The treatment significantly reduced epididymal fat and attenuated the elevated serum resistin, cholesterol, triglycerides, glucose, and insulin with an improved glucose tolerance test. Antiresistin RNA oligo also normalized serum AST and ALT levels with improved pathohistology of NAFLD. Immunoblotting and qRT-PCR revealed that decreased protein and mRNA expression of resistin in fat and liver tissues of the treated mice were associated with reduction of adipose TNF-α and IL-6 expression and secretion into circulation. mRNA and protein expression of hepatic phosphoenolpyruvate carboxykinase (PEPCK) and sterol regulatory element-binding protein-1c (SREBP-1c) were also significantly decreased in the treated mice. Our results suggest that resistin may exacerbate NAFLD in metabolic syndrome through upregulating inflammatory cytokines and hepatic PEPCK and SREBP-1c. Antiresistin RNA oligo ameliorated metabolic abnormalities and histopathology of NAFLD through attenuating proinflammatory cytokines.

Adipocytokine expression associated with miRNA regulation and diagnosis of NASH in obese patients with NAFLD

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is strongly associated with visceral adiposity. The secretion of adipocytokines from white adipose tissue (WAT) promoting necroinflammation, and/or fibrosis may play important roles in the pathogenesis of non-alcoholic steatohepatits (NASH). In a previous study, reduced expression of a number of miRNA species in WAT concomitant with histological diagnosis of NASH was successfully demonstrated. In this study, we measure the expression of several predicted miRNA regulatory targets relevant to NAFLD and NASH including mTOR, FAS, IL20, SEMA4C, ADAMTS6 and IL13RA. We then examine hepatic receptor expression by immunohistochemical staining and qPCR.

METHODS

White adipose tissue was collected from 24 obese patients undergoing bariatric surgery with biopsy-proven NAFLD. Extracted total RNAs from the adipose tissue were reverse transcribed and profiled for gene expression by qPCR for specific individual mRNA targets defined after identification by any two of three of the major prediction services: miRanda, TarBase or PicTar. All liver biopsies were read by a singly hepatopathologist. The same liver tissue was used to stain for hepatic receptor expression for FASLG and IL20. Additionally, the same tissue was used for qPCR for FASLG and IL20.

RESULTS

Increases in the expression of IL13RA, mTOR, IL20, SEMA4C and FAS were detected and negatively correlated with putative regulatory miRNA. Hepatic receptor expression for FAS and IL20 was noted to correlate with markers of inflammation and severity of NAFLD.

CONCLUSION

These data are consistent with the hypothesis that specific adipocytokines secreted by WAT will impact hepatic tissue and participate in the pathogenesis of NASH.

Angiogenesis and liver fibrosis

Recent data indicate that hepatic angiogenesis, regardless of the etiology, takes place in chronic liver diseases (CLDs) that are characterized by inflammation and progressive fibrosis. Because anti-angiogenic therapy has been found to be efficient in the prevention of fibrosis in experimental models of CLDs, it is suggested that blocking angiogenesis could be a promising therapeutic option in patients with advanced fibrosis. Consequently, efforts are being directed to revealing the mechanisms involved in angiogenesis during the progression of liver fibrosis. Literature evidences indicate that hepatic angiogenesis and fibrosis are closely related in both clinical and experimental conditions. Hypoxia is a major inducer of angiogenesis together with inflammation and hepatic stellate cells. These profibrogenic cells stand at the intersection between inflammation, angiogenesis and fibrosis and play also a pivotal role in angiogenesis. This review mainly focuses to give a clear view on the relevant features that communicate angiogenesis with progression of fibrosis in CLDs towards the-end point of cirrhosis that may be translated into future therapies. The pathogenesis of hepatic angiogenesis associated with portal hypertension, viral hepatitis, non-alcoholic fatty liver disease and alcoholic liver disease are also discussed to emphasize the various mechanisms involved in angiogenesis during liver fibrogenesis.

Circulating level of CTRP1 in patients with nonalcoholic fatty liver disease (NAFLD): is it through insulin resistance?

Nonalcoholic fatty liver disease (NAFLD) is considered as one of the most common liver diseases. It is robustly linked to obesity and insulin resistance and is regarded as hepatic manifestation of metabolic syndrome (MetS). Adipokines are involved in the pathophysiology of liver diseases. The aim of this study was to evaluate the plasma concentrations of CTRP1 (complement-C1q TNF-related protein 1) in 22 patients with NAFLD, 22 patients with type 2 diabetes mellitus (T2DM), 22 patients with NAFLD+T2DM and 21 healthy controls, as well as their correlation with the level of metabolic and hepatic parameters. Plasma concentration of CTRP1 was measured with ELISA method. Plasma concentration of CTRP1 in patients with NAFLD, T2DM and NAFLD+T2DM were significantly higher than healthy subjects (p<0.0001). Moreover, we observed significant positive correlations between plasma level of CTRP1 and fasting blood glucose (FBG) (p<0.001), homeostasis model assessment of insulin resistance (HOMA-IR) (p<0.001), body mass index (BMI) (p = 0.001), alanine amino transferase (ALT) (p = 0.002), gamma glutamyl transferase (γ-GT) (p<0.001) and liver stiffness (LS) (p<0.001). Our results indicate the strong association of CTRP1 with insulin resistance in NAFLD. Also, it seems that CTRP1 can be considered as an emerging biomarker for NAFLD, however, more studies are necessary to unravel the role of CTRP1 in NAFLD pathogenesis.

Resveratrol improves insulin resistance, glucose and lipid metabolism in patients with non-alcoholic fatty liver disease: a randomized controlled trial

BACKGROUND

Non-alcoholic fatty liver disease is a major health problem worldwide. Resveratrol is a natural polyphenol found in edible plants that has a variety of biochemical and physiological effects.

AIMS

To evaluate the effect of resveratrol on insulin resistance, glucose and lipid metabolism in non-alcoholic fatty liver disease.

METHODS

Double-blind, randomized, placebo-controlled trial: 60 subjects with non-alcoholic fatty liver disease were given 2 placebo capsules (placebo group) or 2 150mg resveratrol capsules (resveratrol group) twice daily for three months. Liver ultrasound imaging, anthropometric profile, serum liver enzymes, insulin, glucose, C-peptide, lipid profile, and inflammation-related cytokines were compared pre and post-treatment.

RESULTS

Compared with the placebo group, resveratrol significantly decreased aspartate aminotransferase, glucose and low-density lipoprotein cholesterol [-6.00 (-9.00, -3.00) IU/L, -0.64±0.31mmol/L, and -0.41±0.35mmol/L, respectively, P≤0.001] alanine aminotransferase, total cholesterol [-7.00 (-11.0, -2.50) IU/L and -0.67±0.50mmol/L, respectively, P=0.002], and homeostasis model assessment insulin resistance index (-0.60±1.15, P=0.016). In the resveratrol group significant reductions of the levels of tumour necrosis factor-alpha, cytokeratin 18 fragment, and fibroblast growth factor 21 [-0.53±1.30pg/mL, -26.9 (-70.3, 5.12) IU/L and -23.3 (-43.0, 0.31) pg/mL, respectively, P<0.05] and elevation of adiponectin level [1.22 (-0.37, 1.60) ng/mL, P=0.025] were observed.

CONCLUSION

Resveratrol supplementation may benefit patients with non-alcoholic fatty liver disease.

Blockade of interleukin 6 signalling ameliorates systemic insulin resistance through upregulation of glucose uptake in skeletal muscle and improves hepatic steatosis in high-fat diet fed mice

BACKGROUND & AIMS

Mice fed high-fat diet (HFD) demonstrate obesity-related systemic insulin resistance (IR). Aim of this study is to clarify the role of interleukin (IL)-6 in IR in vivo focusing on skeletal muscle, adipose tissue and liver.

METHODS

Plasma markers of IR and hepatic IL-6 signalling were examined in eight-week HFD feeding C57/BL6 mice. Furthermore, IR-related molecules in skeletal muscles, adipose tissues and livers were investigated following a single injection of anti- IL-6 receptor neutralizing antibody (MR16-1) in two-week HFD feeding mice. To investigate the role of IL-6 in hepatic steatosis by prolonged HFD, hepatic triglyceride accumulation was assessed in eight-week HFD feeding mice with continuous MR16-1 treatment.

RESULTS

High-fat diet for both 2 and 8 weeks elevated plasma IL-6, insulin and leptin, which were decreased by MR16-1 treatment. A single injection of MR16-1 ameliorated IR as assessed by glucose and insulin tolerance test, which may be attributable to upregulation of glucose transporter type 4 via phosphorylation of AMP-activated protein kinase as well as upregulation of peroxisome proliferator-activated receptor alpha in livers and, particularly, in skeletal muscles. MR16-1 also decreased mRNA expression of leptin and tumour necrosis factor-alpha and increased that of adiponectin in adipose tissue. High-fat diet for 8 weeks, not 2 weeks, induced hepatic steatosis and increased hepatic triglyceride content, all of which were ameliorated by MR16-1 treatment.

CONCLUSIONS

Blockade of excessive IL-6 stimulus ameliorated HFD-induced IR in a skeletal muscle and modulated the production of adipokines from an early stage of NAFLD, leading to prevention of liver steatosis for a long term.

Protective effect of oroxylin A against lipopolysaccharide and/or D-galactosamine-induced acute liver injury in mice

BACKGROUND

Oroxylin A, a natural flavonoid isolated from Scutellariae baicalensis, has been reported to possess a wide spectrum of pharmacologic activities. However, the effects of oroxylin A on liver injury are poor understood. The purpose of this study was to investigate the effects of oroxylin A on acute liver injury in mice induced by lipopolysaccharide and/or D-galactosamine (LPS and/or D-GalN).

METHODS

Mice acute liver injury model was induced by LPS (50 μg/kg) and/or GalN (800 mg/kg). Serum alanine aminotransferase, aspartate aminotransferase, and tumor necrosis factor-α levels, hepatic tissue histology, malondialdehyde content, and myeloperoxidase activity were analyzed. Meanwhile, nuclear factor kappa B (NF-κB), heme oxygenase-1 (HO-1), and nuclear factor erythroid2-related factor 2 (Nrf2) expression were detected by Western blotting.

RESULTS

The results showed that oroxylin A dose-dependently inhibited LPS and/or GalN-induced serum alanine aminotransferase, aspartate aminotransferase, and tumor necrosis factor-α levels. Hepatic malondialdehyde content and myeloperoxidase activity were also suppressed by oroxylin A. We also found that oroxylin A inhibited LPS and/or GalN-induced toll like receptor 4 (TLR4) expression and NF-κB activation. In addition, oroxylin A upregulated the expression of Nrf2 and HO-1 in a dose-dependent manner.

CONCLUSIONS

In conclusion, oroxylin A protected against LPS and/or GalN-induced liver injury through activating Nrf2 and inhibiting TLR4 signaling pathway.

Republished: Non-alcoholic fatty liver disease: non-invasive investigation and risk stratification

Non-alcoholic fatty liver disease (NAFLD) encompasses a histological spectrum of liver disease, from simple steatosis through to cirrhosis. As the worldwide rates of obesity have increased, NAFLD has become the commonest cause of liver disease in many developed countries, affecting up to a third of the population. The majority of patients have simple steatosis that carries a relatively benign prognosis. However, a significant minority have non-alcoholic steatohepatitis, and have increased liver related and cardiovascular mortality. Identifying those at risk of progressive disease is crucial. Liver biopsy remains the gold standard investigation for assessing stage of disease but its invasive nature makes it impractical for widespread use as a prognostic tool. Non-invasive tools for diagnosis and disease staging are required, reserving liver biopsy for those patients where it offers clinically relevant additional information. This review discusses the non-invasive modalities available for assessing steatosis, steatohepatitis and fibrosis. We propose a pragmatic approach for the assessment of patients with NAFLD to identify those at high risk of progressive disease who require referral to specialist services.

Adipokines, vascular wall, and cardiovascular disease: a focused overview of the role of adipokines in the pathophysiology of cardiovascular disease

Epidemiological evidence has shown that abdominal obesity is closely associated with the development of cardiovascular (CV) disease, suggesting that it might be considered as an independent CV risk factor. However, the pathophysiological mechanisms responsible for the association between these 2 clinical entities remain largely unknown. Adipocytes are considered able to produce and secrete chemical mediators known as "adipokines" that may exert several biological actions, including those on heart and vessels. Of interest, a different adipokine profile can be observed in the plasma of patients with obesity or metabolic syndrome compared with healthy controls. We consider the main adipokines, focusing on their effects on the vascular wall and analyzing their role in CV pathophysiology.

Resistin: insulin resistance to malignancy

Adipose tissue is recognized as an endocrine organ that secretes bioactive substances known as adipokines. Excess adipose tissue and adipose tissue dysfunction lead to dysregulated adipokine production that can contribute to the development of obesity-related co-morbidities. Among the various adipokines, resistin, which was initially considered as a determinant of the emergence of insulin resistance in obesity, has appeared as an important link between obesity and inflammatory processes. Several experimental and clinical studies have suggested an association between increased resistin levels and severe conditions associated with obesity such as cardiovascular disease and malignancies. In this review, we present the growing body of evidence that human resistin is an inflammatory biomarker and potential mediator of obesity-associated diseases. A common pathway seems to involve the combined alteration of immune and inflammatory processes that favor metabolic disturbances, atherosclerosis and carcinogenesis. The mode of action and the signaling pathways utilized by resistin in its interactions with target cells could involve oxidative and nitrosative stress. Therefore, resistin could function as a key molecule in the complications of obesity development and could potentially be used as a diagnostic and prognostic marker.

Lactobacillus rhamnosus LA68 and Lactobacillus plantarum WCFS1 differently influence metabolic and immunological parameters in high fat diet-induced hypercholesterolemia and hepatic steatosis

TwoLactobacillusstrains were evaluated for their effects on high fat diet induced pathology in mice.

Oxidative stress in obesity: a critical component in human diseases

Obesity, a social problem worldwide, is characterized by an increase in body weight that results in excessive fat accumulation. Obesity is a major cause of morbidity and mortality and leads to several diseases, including metabolic syndrome, diabetes mellitus, cardiovascular, fatty liver diseases, and cancer. Growing evidence allows us to understand the critical role of adipose tissue in controlling the physic-pathological mechanisms of obesity and related comorbidities. Recently, adipose tissue, especially in the visceral compartment, has been considered not only as a simple energy depository tissue, but also as an active endocrine organ releasing a variety of biologically active molecules known as adipocytokines or adipokines. Based on the complex interplay between adipokines, obesity is also characterized by chronic low grade inflammation with permanently increased oxidative stress (OS). Over-expression of oxidative stress damages cellular structures together with under-production of anti-oxidant mechanisms, leading to the development of obesity-related complications. The aim of this review is to summarize what is known in the relationship between OS in obesity and obesity-related diseases.

4Ps medicine of the fatty liver: the research model of predictive, preventive, personalized and participatory medicine-recommendations for facing obesity, fatty liver and fibrosis epidemics

Relationship between adipose tissue and fatty liver, and its possible evolution in fibrosis, is supported by clinical and research experience. Given the multifactorial pathogenesis of non-alcoholic fatty liver disease (NAFLD), treatments for various contributory risk factors have been proposed; however, there is no single validated therapy or drug association recommended for all cases which can stand alone. Mechanisms, diagnostics, prevention and treatment of obesity, fatty liver and insulin resistance are displayed along with recommendations and position points. Evidences and practice can get sustainable and cost-benefit valuable outcomes by participatory interventions. These recommendations can be enhanced by comprehensive research projects, addressed to societal issues and innovation, market appeal and industry development, cultural acceptance and sustainability. The basis of participatory medicine is a greater widespread awareness of a condition which is both a disease and an easy documented and inclusive clue for associated diseases and unhealthy lifestyle. This model is suitable for addressing prevention and useful for monitoring improvement, worsening and adherence with non-invasive imaging tools which allow targeted approaches. The latter include health psychology and nutritional and physical exercise prescription expertise disseminated by continuous medical education but, more important, by concrete curricula for training undergraduate and postgraduate students. It is possible and recommended to do it by early formal teaching of ultrasound imaging procedures and of practical lifestyle intervention strategies, including approaches aimed to healthier fashion suggestions. Guidelines and requirements of research project funding calls should be addressed also to NAFLD and allied conditions and should encompass the goal of training by research and the inclusion of participatory medicine topics. A deeper awareness of ethics of competences in health professionals and the articulation of knowledge, expertise and skills of medical doctors, dieticians, health psychologists and sport and physical exercise graduates are the necessary strategy for detectin a suboptimal health status and achieving realistically beneficial lifestyle changes. “The devil has put a penalty on all things we enjoy in life. Either we suffer in health or we suffer in soul or we get fat” (Albert Einstein); the task of medical research and intervention is to make possible to enjoy life also without things that make sufferance in health and souls and which excessively increase body fat.

Association between nonalcoholic fatty liver disease and colorectal adenoma: a systemic review and meta-analysis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is considered to be a hepatic manifestation of metabolic syndrome (MetS) and the most common chronic liver disease worldwide. The association between NAFLD and colorectal adenoma has been investigated in multiples studies but the results have been conflicting. We performed a systematic review and meta-analysis to evaluate this in asymptomatic patients who underwent screening colonoscopy.

METHODS

We searched the literatures of all languages from PubMed, EMBASE and the Cochrane library from January 1, 1980 through July 15, 2014. Combined and subgroup analyses stratified by study designs, study locations, characteristics of adenoma (location, size, number, and advanced adenoma) were performed.

RESULTS

Four cross-sectional and one cohort studies with a total of 6,263 subjects were included in the meta-analysis. NAFLD was significantly associated with colorectal adenoma [pooled odds ratio (OR) 1.74, 95% confidence interval (CI): 1.53-1.97]. The association was more significant in Asian population (pooled OR =1.77, 95% CI: 1.52-2.05, n=3 studies), compared to European/North American population (pooled OR =1.42, 95% CI: 0.75-2.67, n=2 studies). NAFLD was significantly associated with the number of colorectal adenoma (pooled OR =1.78, 95% CI: 1.10-2.86, n=2 studies), but not the location, size, or presence of advanced adenoma.

CONCLUSIONS

Our results suggest NAFLD is significantly associated with the presence of colorectal adenoma in asymptomatic patients undergoing screening colonoscopy. This finding provides additional risk stratifications for applying colorectal cancer (CRC) screening strategies. However, more studies of western population are needed to further investigate the ethnic disparity.

Oral coenzyme Q10 supplementation in patients with nonalcoholic fatty liver disease: effects on serum vaspin, chemerin, pentraxin 3, insulin resistance and oxidative stress

BACKGROUNDS AND AIMS

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver injury. Chronic exposure to oxidative stress leads to depletion of liver antioxidants and abnormal cytokine production; antioxidant therapy is one of the main therapeutic lines in NAFLD. In the current study we aimed to investigate the effect of coenzyme Q10 (coQ10) therapy on several adipocytokines and insulin resistance in patients with NAFLD.

METHODS

In the current randomized double-blind placebo controlled trial 44 NAFLD patients were enrolled. After randomization into two groups, 22 patients received 100 mg/day coQ10 capsules and 22 patients received placebo daily for 4 weeks. BMI and WHR were calculated for patients at the beginning and end of the study and blood samples were obtained from the patients to measure serum concentrations of aspartate aminotransferase (AST), alanine aminotransferase (ALT), fasting serum glucose (FSG), insulin resistance (IR), vaspin, chemerin, pentraxin 3 (PTX3) and markers of oxidative stress including total antioxidant capacity (TAC) and malondialdehyde (MDA).

RESULTS

After 4 weeks of coQ10 supplementation, waist circumference (WC) and serum AST and TAC concentrations significantly decreased in intervention group (p <0.05) but no significant changes occurred in placebo-treated group. In stepwise multivariate linear regression model, change in serum FSG was a significant predictor of changes in serum vaspin, chemerin and pentraxin 3 (p <0.001).

CONCLUSIONS

The present study showed a potential for coQ10 therapy in improving several anthropometric and biochemical variables in NAFLD. Longer studies with higher doses of coQ10 are required to further evaluate this potential benefit.

Non-alcoholic fatty liver disease in children: focus on nutritional interventions

With increasing prevalence of childhood obesity, non-alcoholic fatty liver disease (NAFLD) has emerged as the most common cause of liver disease among children and adolescents in industrialized countries. It is generally recognized that both genetic and environmental risk factors contribute to the pathogenesis of NAFLD. Recently, there has been a growing body of evidence to implicate altered gut microbiota in the development of NAFLD through the gut-liver axis. The first line of prevention and treatment of NAFLD in children should be intensive lifestyle interventions such as changes in diet and physical activity. Recent advances have been focused on limitation of dietary fructose and supplementation of antioxidants, omega-3 fatty acids, and prebiotics/probiotics. Convincing evidences from both animal models and human studies have shown that reduction of dietary fructose and supplement of vitamin E, omega-3 fatty acids, and prebiotics/probiotics improve NAFLD.

Nonalcoholic fatty liver disease: A comprehensive review of a growing epidemic

Nonalcoholic fatty liver disease (NAFLD) is quickly becoming one of the most prominent causes of liver disease worldwide. The increasing incidence of NAFLD is tied to the obesity epidemic and the subsequent metabolic derangements brought along with it. Current efforts to elucidate the mechanism and causes of the disease have answered some questions, but much remains unknown about NAFLD. The aim of this article is to discuss the current knowledge regarding the pathogenesis of the disease, as well as the current and future diagnostic, preventative, and therapeutic options available to clinicians for the management of NAFLD.

Noninvasive biomarkers in non-alcoholic fatty liver disease: Current status and a glimpse of the future

The development of non invasive biomarkers of disease has become a major focus of interest in nonalcoholic fatty liver disease (NAFLD). The large prevalence of the disease and the invasive nature of the investigation means that screening with liver biopsy is impractical. In addition to screening, the differentiation of those with simple steatosis vs steatohepatitis and fibrosis is clinically important as the prognosis of each differs. Serum biomarkers may be a combination of simple markers derived from large data sets or direct markers of disease activity. Serum markers of inflammation, apoptosis and oxidative stress in addition to fibrosis have been extensively studied in patients with NAFLD. Other techniques such as transient elastography, magnetic resonance elastography and acoustic radiation force imaging are becoming more established as noninvasive methods of detecting fibrosis in a variety of chronic liver conditions in addition to NAFLD. Newer high throughput methods such as proteomics and glycomics allow the nonhypothesis-driven identification of novel markers and may also potentially contribute to our understanding of the pathogenesis of the condition. This review addresses some of the methodological issues which need to be considered in the search for the ideal biomarker. It is likely that a combination of serum biomarkers and techniques such as transient elastography may provide the optimal diagnostic discrimination however this remains to be proven in large studies.

Nonalcoholic fatty liver disease increases risk for gastroesophageal reflux symptoms

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is now recognized as a leading cause of liver dysfunction. Gastroesophageal reflux disease (GERD) is a common disorder causing symptoms that often impair patients' quality of life. In recent years, the prevalence of both these diseases has increased, partially overlapping the rise of metabolic disorders.

AIMS

We investigated whether a relation does exist between NAFLD and GERD symptoms.

METHODS

Cross-sectional study among 206 outpatients diagnosed with NAFLD and 183 controls. We collected clinical and laboratory data, assessed severity and frequency of GERD symptoms and the esophageal endoscopic pattern.

RESULTS

The prevalence of GERD symptoms was higher in NAFLD patients than controls (61.2 vs. 27.9%, p < 0.001). We found a positive association between NAFLD and the experiencing of heartburn, regurgitation and belching. GERD symptoms were related to body mass index (BMI) and metabolic syndrome (MetS); a strong association persisted after adjustment for all the covariates (adjusted OR 3.49, 95 CI% 2.24-5.44, p < 0.001).

CONCLUSIONS

Our data show that the prevalence of GERD typical symptoms is higher in patients with NAFLD. GERD was associated with higher BMI and MetS, but not with age and diabetes type 2. NAFLD remained strongly associated with GERD, independently of a coexisting MetS status. Consistent with these findings, MetS can be considered a shared background, but cannot completely explain this correlation. We suggest NAFLD as an independent risk factor for GERD symptoms.

Protective effects and mechanisms of total alkaloids of Rubus alceaefolius Poir on non‑alcoholic fatty liver disease in rats

The plant Rubus alceaefolius Poir is used as a hepatic protectant in Traditional Chinese Medicine. The aim of the present study was to confirm the protective effect of the total alkaloids of Rubus alceaefolius Poir (TARAP) on the liver and to evaluate the potential molecular mechanisms associated with adipocytokines underlying non-alcoholic fatty liver disease (NAFLD) in rats. To generate the NAFLD model, Sprague-Dawley rats were administered a high‑fat diet and following 12 weeks of model construction, rats were orally treated with a positive control drug and different doses of TARAP daily for 28 days. The rats were then sacrificed and the livers were collected to evaluate the liver index (LI) and observe histological changes by hematoxylin and eosin (H&E) staining. The secretion levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum were examined by ELISA. Finally, the expression levels of leptin (LEP), resistin and adiponectin (APN) in liver tissues were determined by immunohistochemistry (IHC). The results demonstrated that, in the group treated with methionine and choline bitartrate tablets and in the groups treated with different doses of TARAP, there was a significant reduction in the LI (P<0.05 or P<0.01), a downregulation of the secretion levels of ALT and AST, reduced levels of LEP and resistin and an increased expression of APN in the liver of NAFLD rats compared with the model group. Furthermore, the effect of TARAP treatment of NAFLD rats was dose dependent. In conclusion, TARAP is a potential agent for downregulating LEP and resistin and upregulating APN expression in rats with NAFLD. Furthermore, TARAP may be a potential candidate for improving treatment responses in patients with NAFLD.

Molecular pathways in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a clinicopathological change characterized by the accumulation of triglycerides in hepatocytes and has frequently been associated with obesity, type 2 diabetes mellitus, hyperlipidemia, and insulin resistance. It is an increasingly recognized condition that has become the most common liver disorder in developed countries, affecting over one-third of the population and is associated with increased cardiovascular- and liver-related mortality. NAFLD is a spectrum of disorders, beginning as simple steatosis. In about 15% of all NAFLD cases, simple steatosis can evolve into non-alcoholic steatohepatitis, a medley of inflammation, hepatocellular injury, and fibrosis, often resulting in cirrhosis and even hepatocellular cancer. However, the molecular mechanism underlying NAFLD progression is not completely understood. Its pathogenesis has often been interpreted by the “double-hit” hypothesis. The primary insult or the “first hit” includes lipid accumulation in the liver, followed by a “second hit” in which proinflammatory mediators induce inflammation, hepatocellular injury, and fibrosis. Nowadays, a more complex model suggests that fatty acids (FAs) and their metabolites may be the true lipotoxic agents that contribute to NAFLD progression; a multiple parallel hits hypothesis has also been suggested. In NAFLD patients, insulin resistance leads to hepatic steatosis via multiple mechanisms. Despite the excess hepatic accumulation of FAs in NAFLD, it has been described that not only de novo FA synthesis is increased, but FAs are also taken up from the serum. Furthermore, a decrease in mitochondrial FA oxidation and secretion of very-low-density lipoproteins has been reported. This review discusses the molecular mechanisms that underlie the pathophysiological changes of hepatic lipid metabolism that contribute to NAFLD.

Chronic stress induces steatohepatitis while decreases visceral fat mass in mice

Background

Prolonged stress leads over time to allostatic load on the body and is likely to exacerbate a disease process. Long-term of stress exposure is one of a risk factor for metabolism-related diseases such as obesity and type 2 diabetes. However, the relationship between chronic stress and non-alcoholic fatty liver disease (NAFLD) remain unknown.

Methods

To address the hypothesis that chronic stress associate to NAFLD development, we subjected C57bl/6 mice to electric foot shock and restraint stress for 12 weeks to set up chronic stress model. Then the serum and hepatic triglyceride (TG), total cholesterol (TC) were measured. Hepatic HE and Oil red O staining were used to specify the state of the NAFLD. To investigate whether inflammation takes part in the stress-induced NAFLD process, related visceral fat, serum and hepatic inflammatory factors were measured.

Results

We observed that chronic stress led to an overall increase of hepatic triglyceride and cholesterol while decreasing body weight and visceral fat mass. Microvesicular steatosis, lobular inflammation and ballooning degeneration were seen in stress liver section. This effect was correlated with elevated hepatic and serum inflammatory factors. Although the amount of visceral fat was decreased in stress group, various adipocytokines were elevated.

Conclusions

We showed that chronic stress is associated to NAFLD and chronic inflammation in visceral fat, though food intake and visceral fat mass were decreased. These results may contribute to better understanding of the mechanism from steatosis to steatohepatitis, and propose a novel insight into the prevention and treatment of NAFLD.

Steatosis and steatohepatitis: complex disorders

Non-alcoholic fatty liver disease (NAFLD) which includes steatosis and steatohepatitis, in particular non-alcoholic steatohepatitis (NASH), is a rising health problem world-wide and should be separated from alcoholic steatohepatitis (ASH). NAFLD is regarded as hepatic manifestation of the metabolic syndrome (MetSy), being tightly linked to obesity and type 2 diabetes mellitus (T2DM). Development of steatosis, liver fibrosis and cirrhosis often progresses towards hepatocellular carcinogenesis and frequently results in the indication for liver transplantation, underlining the clinical significance of this disease complex. Work on different murine models and several human patients studies led to the identification of different molecular key players as well as epigenetic factors like miRNAs and SNPs, which have a promoting or protecting function in AFLD/ASH or NAFLD/NASH. To which extent they might be translated into human biology and pathogenesis is still questionable and needs further investigation regarding diagnostic parameters, drug development and a better understanding of the genetic impact. In this review we give an overview about the currently available knowledge and recent findings regarding the development and progression of this disease.

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.

Role of innate immune response in non-alcoholic Fatty liver disease: metabolic complications and therapeutic tools

Non-alcoholic fatty liver disease (NAFLD) is currently the most common liver disease worldwide, both in adults and children. It is characterized by an aberrant lipid storage in hepatocytes, named hepatic steatosis. Simple steatosis remains a benign process in most affected patients, while some of them develop superimposed necroinflammatory activity with a non-specific inflammatory infiltrate and a progression to non-alcoholic steatohepatitis with or without fibrosis. Deep similarity and interconnections between innate immune cells and those of liver parenchyma have been highlighted and showed to play a key role in the development of chronic liver disease. The liver can be considered as an “immune organ” because it hosts non-lymphoid cells, such as macrophage Kupffer cells, stellate and dendritic cells, and lymphoid cells. Many of these cells are components of the classic innate immune system, enabling the liver to play a major role in response to pathogens. Although the liver provides a “tolerogenic” environment, aberrant activation of innate immune signaling may trigger “harmful” inflammation that contributes to tissue injury, fibrosis, and carcinogenesis. Pathogen recognition receptors, such as toll-like receptors and nucleotide oligomerization domain-like receptors, are responsible for the recognition of immunogenic signals, and represent the major conduit for sensing hepatic and non-hepatic noxious stimuli. A pivotal role in liver inflammation is also played by cytokines, which can initiate or have a part in immune response, triggering hepatic intracellular signaling pathways. The sum of inflammatory signals and deranged substrate handling induce most of the metabolic alteration traits: insulin resistance, obesity, diabetes, hyperlipidemia, and their compounded combined effects. In this review, we discuss the relevant role of innate immune cell activation in relation to NAFLD, the metabolic complications associated to this pathology, and the possible pharmacological tools.

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.

The relationship between hepatic resistin overexpression and inflammation in patients with nonalcoholic steatohepatitis

Background

The relationship between resistin and non-alcoholic steatohepatitis (NASH) is not clear, some studies claimed that serum resistin levels were associated with neither the presence of NASH nor its severity, others declared that serum resistin was related with inflammation and fibrosis in NASH. Our animal study verified that the distribution of resistin in the liver is correlated with inflammation in NASH. However, there is no pertinent study in humans.

Methods

Thirty patients with NASH, 28 simple steatosis, and 43 controls were recruited. Blood was collected for resistin, liver chemistries, fasting insulin and some metabolic parameters. Liver histology was scored according to NAFLD activity scoring system. Hepatic resistin expression was examined by real-time polymerase chain reaction, immunohistochemistry. Resistin protein expression was confirmed by western blotting in 13 patients with concomitant NAFLD and gallstone.

Results

Serum resistin was significantly elevated in both NASH and simple steatotic subjects compared with controls (all P < 0.05). Hepatic resistin was significantly increased in NASH patients in both mRNA and protein levels than those in simple steatosis and control subjects (all P < 0.05). Both serum and hepatic resistin had a correlation with obesity, but not with insulin resistance. The distribution of resistin positive cells was predominantly in perisinusoidal cells (such as Kupffer cells and hepatic stellate cells) in human NASH. Multivariate analysis revealed that waist-hip ratio, higher serum triglyceride, and hyperresistinemia were independent factors related to higher grade of steatosis; whereas hepatic resistin and serum cytokeratin predict NASH and severity of liver fibrosis.

Conclusions

Hepatic resistin overexpression in NASH patients is associated with the severity of liver inflammation and fibrosis. Liver-derived resistin may be involved in the pathogenesis of human NASH.

Clinical approaches to non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) ranges from simple steatosis to nonalcoholic steatohepatitis (NASH), leading to fibrosis and potentially cirrhosis, and it is one of the most common causes of liver disease worldwide. NAFLD is associated with other medical conditions such as metabolic syndrome, obesity, cardiovascular disease and diabetes. NASH can only be diagnosed through liver biopsy, but noninvasive techniques have been developed to identify patients who are most likely to have NASH or fibrosis, reducing the need for liver biopsy and risk to patients. Disease progression varies between individuals and is linked to a number of risk factors. Mechanisms involved in the pathogenesis are associated with diet and lifestyle, influx of free fatty acids to the liver from adipose tissue due to insulin resistance, hepatic oxidative stress, cytokines production, reduced very low-density lipoprotein secretion and intestinal microbiome. Weight loss through improved diet and increased physical activity has been the cornerstone therapy of NAFLD. Recent therapies such as pioglitazone and vitamin E have been shown to be beneficial. Omega 3 polyunsaturated fatty acids and statins may offer additional benefits. Bariatric surgery should be considered in morbidly obese patients. More research is needed to assess the impact of these treatments on a long-term basis. The objective of this article is to briefly review the diagnosis, management and treatment of this disease in order to aid clinicians in managing these patients.

Clinical approaches to non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) ranges from simple steatosis to nonalcoholic steatohepatitis (NASH), leading to fibrosis and potentially cirrhosis, and it is one of the most common causes of liver disease worldwide. NAFLD is associated with other medical conditions such as metabolic syndrome, obesity, cardiovascular disease and diabetes. NASH can only be diagnosed through liver biopsy, but noninvasive techniques have been developed to identify patients who are most likely to have NASH or fibrosis, reducing the need for liver biopsy and risk to patients. Disease progression varies between individuals and is linked to a number of risk factors. Mechanisms involved in the pathogenesis are associated with diet and lifestyle, influx of free fatty acids to the liver from adipose tissue due to insulin resistance, hepatic oxidative stress, cytokines production, reduced very low-density lipoprotein secretion and intestinal microbiome. Weight loss through improved diet and increased physical activity has been the cornerstone therapy of NAFLD. Recent therapies such as pioglitazone and vitamin E have been shown to be beneficial. Omega 3 polyunsaturated fatty acids and statins may offer additional benefits. Bariatric surgery should be considered in morbidly obese patients. More research is needed to assess the impact of these treatments on a long-term basis. The objective of this article is to briefly review the diagnosis, management and treatment of this disease in order to aid clinicians in managing these patients.

Systematic review with meta-analysis: non-invasive assessment of non-alcoholic fatty liver disease--the role of transient elastography and plasma cytokeratin-18 fragments

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) affects 15-40% of the general population. Some patients have non-alcoholic steatohepatitis (NASH) and progressive fibrosis, and would be candidates for monitoring and treatment.

AIM

To review current literature on the use of non-invasive tests to assess the severity of NAFLD.

METHODS

Systematic literature searching identified studies evaluating non-invasive tests of NASH and fibrosis using liver biopsy as the reference standard. Meta-analysis was performed for areas with adequate number of publications.

RESULTS

Serum tests and physical measurements like transient elastography (TE) have high negative predictive value (NPV) in excluding advanced fibrosis in NAFLD patients. The NAFLD fibrosis score comprises of six routine clinical parameters and has been endorsed by current American guidelines as a screening test to exclude low-risk individuals. The pooled sensitivities and specificities for TE to diagnose F ≥ 2, F ≥ 3 and F4 disease were 79% and 75%, 85% and 85%, and 92% and 92% respectively. Liver stiffness measurement often fails in obese patients, but the success rate can be improved with the use of the XL probe. A number of biomarkers have been developed for the diagnosis of NASH, but few were independently validated. Serum/plasma cytokeratin-18 fragments have been most extensively evaluated and have a pooled sensitivity of 66% and specificity of 82% in diagnosing NASH.

CONCLUSIONS

Current non-invasive tests are accurate in excluding advanced fibrosis in NAFLD patients, and may be used for initial assessment. Further development and evaluation of NASH biomarkers are needed.

Resistin and visfatin in steatotic and non-steatotic livers in the setting of partial hepatectomy under ischemia-reperfusion

BACKGROUND & AIMS

This study examined whether the regulation of resistin and visfatin could reduce damage and improve regeneration in both steatotic and non-steatotic livers undergoing partial hepatectomy under ischemia-reperfusion, a procedure commonly applied in clinical practice to reduce bleeding.

METHODS

Resistin and visfatin were pharmacologically modulated in lean and obese animals undergoing partial hepatectomy under ischemia-reperfusion.

RESULTS

No evident role for these adipocytokines was observed in non-steatotic livers. However, obese animals undergoing liver surgery showed increased resistin in liver and plasma, without changes in adipose tissue, together with visfatin downregulation in liver and increment in plasma and adipose tissue. Endogenous resistin maintains low levels of visfatin in the liver by blocking its hepatic uptake from the circulation, thus regulating the visfatin detrimental effects on hepatic damage and regenerative failure. Indeed, the administration of anti-resistin antibodies increased hepatic accumulation of adipocyte-derived visfatin, exacerbating damage and regenerative failure. Interestingly, treatment with anti-visfatin antibodies protected steatotic livers, and similar results were obtained with the concomitant inhibition of resistin and visfatin. Thus, when visfatin was inhibited, the injurious effects of anti-resistin antibodies disappeared. Herein we show that upregulation of visfatin increased NAD levels in the remnant steatotic liver, whereas visfatin inhibition decreased them. These later observations suggest that visfatin may favour synthesis of NAD instead of DNA and induces alterations in amino acid metabolism-urea cycle and NO production, overall negatively affecting liver viability.

CONCLUSIONS

Our results indicate the clinical potential of visfatin blocking-based therapies in steatotic livers undergoing partial hepatectomy with ischemia-reperfusion.

Adiponectin and resistin protect steatotic livers undergoing transplantation

BACKGROUND & AIMS

Numerous steatotic livers are discarded for transplantation because of their poor tolerance to ischemia-reperfusion. Controversial roles for adiponectin and related adipocytokines visfatin and resistin have been described in different liver pathologies, nevertheless it is unknown their possible implication in ischemia-reperfusion injury associated with liver transplantation. Our study aimed at characterizing the role of the adiponectin-derived molecular pathway in transplantation with steatotic and non-steatotic liver grafts.

METHODS

Steatotic and non-steatotic liver transplantation was carried out and the hepatic levels of adiponectin, visfatin and resistin were measured and modulated either pharmacologically or surgically.

RESULTS

Steatotic liver grafts exhibited downregulation of both adiponectin and resistin when subjected to transplantation. Adiponectin pre-treatment only protected steatotic grafts and did it so through a visfatin-independent and resistin-dependent mechanism. Adiponectin-derived resistin accumulation activated the PI3K/Akt pathway, unravelling AMPK as an upstream mediator of adiponectin's actions in steatotic grafts. Strategies aimed at increasing adiponectin including either AMPK activators or the induction of ischemic preconditioning (which activates AMPK) increased resistin accumulation, prevented the downregulation of PI3K/Akt pathway and protected steatotic liver grafts. Conversely, PI3K/Akt pathway upregulation and hepatic protection induced by adiponectin were abolished when resistin action was inhibited.

CONCLUSIONS

Our findings reveal a new protective pathway in steatotic liver transplantation, namely AMPK-adiponectin-resistin-PI3K/Akt, which may help develop new strategies aimed at increasing either adiponectin or resistin in the steatotic liver undergoing transplant to ultimately increase organ donor pool and reduce waiting list.

An integrated view of liver injury and disease progression in nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is rapidly becoming the most common cause of chronic liver disease globally. NAFLD represents a host of pathophysiologic mechanisms that culminate in the accumulation of fat, in a predominantly macrovesicular pattern, in the liver along with varying degrees of inflammation, hepatocellular injury, apoptosis and fibrosis. The most common mechanism for the development of NAFLD is insulin resistance. Insulin resistance is commonly associated with obesity, although it can develop in individuals who do not have obesity. A consequence of insulin resistance is increased peripheral lipolysis and increased delivery of free fatty acids to the liver. The concept of lipotoxicity emerged as the mechanisms by which fatty acids produce cell injury, promote apoptosis and activate inflammatory pathways were elucidated. While much work has been done mainly in cell culture models, the free fatty acid concentration in the liver is not significantly changed in NAFLD. Recently, the focus has shifted to alterations in other lipid metabolic pathways that appear to play an important role in the genesis of nonalcoholic steatohepatitis, the aggressive form of NAFLD. The innate immune system and the intestinal microbiota have been implicated in the development of NAFLD. These mechanisms are reviewed in this article.

Association of serum adiponectin, leptin, and resistin concentrations with the severity of liver dysfunction and the disease complications in alcoholic liver disease

BACKGROUND AND AIMS

There is growing evidence that white adipose tissue is an important contributor in the pathogenesis of alcoholic liver disease (ALD). We investigated serum concentrations of total adiponectin (Acrp30), leptin, and resistin in patients with chronic alcohol abuse and different grades of liver dysfunction, as well as ALD complications.

MATERIALS AND METHODS

One hundred forty-seven consecutive inpatients with ALD were prospectively recruited. The evaluation of plasma adipokine levels was performed using immunoenzymatic ELISA tests. Multivariable logistic regression was applied in order to select independent predictors of advanced liver dysfunction and the disease complications.

RESULTS

Acrp30 and resistin levels were significantly higher in patients with ALD than in controls. Lower leptin levels in females with ALD compared to controls, but no significant differences in leptin concentrations in males, were found. High serum Acrp30 level revealed an independent association with advanced liver dysfunction, as well as the development of ALD complications, that is, ascites and hepatic encephalopathy.

CONCLUSION

Gender-related differences in serum leptin concentrations may influence the ALD course, different in females compared with males. Serum Acrp30 level may serve as a potential prognostic indicator for patients with ALD.

What does irritable bowel syndrome share with non-alcoholic fatty liver disease?

Non-alcoholic fatty liver disease (NAFLD) and irritable bowel syndrome (IBS) are two very common diseases in the general population. To date, there are no studies that highlight a direct link between NAFLD and IBS, but some recent reports have found an interesting correlation between obesity and IBS. A systematic PubMed database search was conducted highlighting that common mechanisms are involved in many of the local and systemic manifestations of NAFLD, leading to an increased cardiovascular risk, and IBS, leading to microbial dysbiosis, impaired intestinal barrier and altered intestinal motility. It is not known when considering local and systemic inflammation/immune system activation, which one has greater importance in NAFLD and IBS pathogenesis. Also, the nervous system is implicated. In fact, inflammation participates in the development of mood disorders, such as anxiety and depression, characteristics of obesity and consequently of NAFLD and, on the other hand, in intestinal hypersensitivity and dysmotility.

Non-viral causes of liver cancer: does obesity led inflammation play a role?

Liver cancer is the fifth most common cancer worldwide and the third most common cause of cancer mortality. Hepatocellular carcinoma (HCC) accounts for around 90% of primary liver cancers. Chronic infection with hepatitis B and hepatitis C viruses are two of most common causes of liver cancer. However, there are non-viral factors that are associated with liver cancer development. Numerous population studies have revealed strong links between obesity and the development of liver cancer. Obesity can alter hepatic pathology, metabolism and promote inflammation, leading to nonalcoholic fatty liver disease (NAFLD) and the progression to the more severe form, non-alcoholic steatohepatitis (NASH). NASH is characterised by prominent steatosis and inflammation, and can lead to HCC. Here, we discuss the role of obesity in inflammation and the principal signalling mechanisms involved in HCC formation.

Non-alcoholic fatty liver disease: non-invasive investigation and risk stratification

Non-alcoholic fatty liver disease (NAFLD) encompasses a histological spectrum of liver disease, from simple steatosis through to cirrhosis. As the worldwide rates of obesity have increased, NAFLD has become the commonest cause of liver disease in many developed countries, affecting up to a third of the population. The majority of patients have simple steatosis that carries a relatively benign prognosis. However, a significant minority have non-alcoholic steatohepatitis, and have increased liver related and cardiovascular mortality. Identifying those at risk of progressive disease is crucial. Liver biopsy remains the gold standard investigation for assessing stage of disease but its invasive nature makes it impractical for widespread use as a prognostic tool. Non-invasive tools for diagnosis and disease staging are required, reserving liver biopsy for those patients where it offers clinically relevant additional information. This review discusses the non-invasive modalities available for assessing steatosis, steatohepatitis and fibrosis. We propose a pragmatic approach for the assessment of patients with NAFLD to identify those at high risk of progressive disease who require referral to specialist services.

Acute steatohepatitis, due to extreme metabolic dysregulation, as the first presentation of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a slowly progressive chronic disease, with a high prevalence among obese, dyslipidemic or diabetic people, commonly presented as an asymptomatic mild elevation of serum aminotransferases. We report a patient who experienced an acute form of non-alcoholic steatohepatitis, as the first manifestation of NAFLD, due to exacerbation of pre-existing metabolic disorders by an extremely unhealthy lifestyle. A 50-year old, obese, diabetic man presented with a one-week history of jaundice and malaise. Analysis revealed elevated liver enzymes, bilirubin, lipids, and glucose. Based on patient's history, physical examination, laboratory results, and imaging findings, acute non-alcoholic steatohepatitis was established as a diagnosis of exclusion. The patient was started on a low-calorie diet free of carbohydrates and fats, in combination with insulin. A dramatic improvement of clinical and laboratory parameters was observed. In the context of extreme metabolic dysregulation, induced by unhealthy diet, NAFLD may present as an acute steatohepatitis.

Sleep duration and quality in relation to non-alcoholic fatty liver disease in middle-aged workers and their spouses

BACKGROUND & AIMS

Although accumulated evidence implies that short sleep duration and poor sleep quality may lead to an altered metabolic milieu, potentially triggering the development of non-alcoholic fatty liver disease (NAFLD), no studies have explored this association. This study sought to examine whether short sleep duration or poor sleep quality is associated with NAFLD in the general population.

METHODS

We assessed sleep duration and quality using the Pittsburgh Sleep Quality Index in 69,463 middle-aged workers and their spouses and carried out biochemical and anthropometric measurements. The presence of fatty liver was determined using ultrasonographic findings. Logistic regression models were used to evaluate the association of sleep duration and quality with NAFLD, after adjusting for potential confounders.

RESULTS

After controlling for the relevant confounding factors (age, alcohol intake, smoking, physical activity, systolic blood pressure, education level, marital status, presence of job, sleep apnea, and loud snoring), the adjusted odds ratio (95% confidence interval) for NAFLD comparing sleep duration ≤5 h to the reference (>7h) was 1.28 (1.13-1.44) in men and 1.71 (1.38-2.13) in women. After further adjustments for BMI, this association was not significant in men (OR: 1.03, 95% CI: 0.90-1.19) but remained significant in women (OR: 1.59, 95% CI: 1.23-2.05). The multivariate-adjusted odds ratio comparing participants with poor sleep quality vs. participants with good sleep quality was 1.10 (95% CI 1.02-1.19) and 1.36 (95% CI 1.17-1.59) in men and women, respectively.

CONCLUSIONS

In the middle-aged, general population, short sleep duration, and poor sleep quality were significantly associated with an increased risk of NAFLD. Prospective studies are required to confirm this association.