Characterization of pathogenic and prognostic factors of nonalcoholic steatohepatitis associated with obesity

Anti-CD47 antibody treatment attenuates liver inflammation and fibrosis in experimental non-alcoholic steatohepatitis models

BACKGROUND & AIMS

With the epidemic burden of obesity and metabolic diseases, nonalcoholic fatty liver disease (NAFLD) including steatohepatitis (NASH) has become the most common chronic liver disease in the western world. NASH may progress to cirrhosis and hepatocellular carcinoma. Currently, no treatment is available for NASH. Therefore, finding a therapy for NAFLD/NASH is in urgent need. Previously we have demonstrated that mice lacking CD47 or its ligand thrombospondin1 (TSP1) are protected from obesity-associated NALFD. This suggests that CD47 blockade might be a novel treatment for obesity-associated metabolic disease. Thus, in this study, the therapeutic potential of an anti-CD47 antibody in NAFLD progression was determined.

METHODS

Both diet-induced NASH mouse model and human NASH organoid model were utilized in this study. NASH was induced in mice by feeding with diet enriched with fat, fructose and cholesterol (AMLN diet) for 20 weeks and then treated with anti-CD47 antibody or control IgG for 4 weeks. Body weight, body composition and liver phenotype were analysed.

RESULTS

We found that anti-CD47 antibody treatment did not affect mice body weight, fat mass or liver steatosis. However, liver immune cell infiltration, inflammation and fibrosis were significantly reduced by anti-CD47 antibody treatment. In vitro data further showed that CD47 blockade prevented hepatic stellate cell activation and NASH progression in a human NASH organoid model.

CONCLUSION

Collectively, these data suggest that anti-CD47 antibody might be a new therapeutic option for obesity-associated NASH and liver fibrosis.

Soluble Endoglin as a Potential Biomarker of Nonalcoholic Steatohepatitis (NASH) Development, Participating in Aggravation of NASH-Related Changes in Mouse Liver

Nonalcoholic steatohepatitis (NASH) is characterized by hepatic steatosis with inflammation and fibrosis. Membrane endoglin (Eng) expression is shown to participate in fibrosis, and plasma concentrations of soluble endoglin (sEng) are increased in patients with hypercholesterolemia and type 2 diabetes mellitus. We hypothesize that NASH increases both hepatic Eng expression and sEng in blood and that high levels of sEng modulate cholesterol and bile acid (BA) metabolism and affect NASH progression. Three-month-old transgenic male mice overexpressing human sEng and their wild type littermates are fed for six months with either a high-saturated fat, high-fructose high-cholesterol (FFC) diet or a chow diet. Evaluation of NASH, Liquid chromatography-mass spectrometry (LC/MS) analysis of BA, hepatic expression of Eng, inflammation, fibrosis markers, enzymes and transporters involved in hepatic cholesterol and BA metabolism are assessed using Real-Time Quantitative Reverse Transcription Polymerase Chain reaction (qRT-PCR) and Western blot. The FFC diet significantly increases mouse sEng levels and increases hepatic expression of Eng. High levels of human sEng results in increased hepatic deposition of cholesterol due to reduced conversion into BA, as well as redirects the metabolism of triglycerides (TAG) to its accumulation in the liver, via reduced TAG elimination by β-oxidation combined with reduced hepatic efflux. We propose that sEng might be a biomarker of NASH development, and the presence of high levels of sEng might support NASH aggravation by impairing the essential defensive mechanism protecting NASH liver against excessive TAG and cholesterol accumulation, suggesting the importance of high sEng levels in patients prone to develop NASH.

Astaxanthin attenuates hepatic damage and mitochondrial dysfunction in non-alcoholic fatty liver disease by up-regulating the FGF21/PGC-1α pathway

BACKGROUND AND PURPOSE

Non-alcoholic fatty liver disease (NAFLD) is considered to be one of the most common chronic liver diseases across worldwide. Astaxanthin (Ax) is a carotenoid, and beneficial effects of astaxanthin, including anti-oxidative, anti-inflammatory, and anti-tumour activity, have been identified. The present study aimed to elucidate the protective effect of astaxanthin against NAFLD and its underlying mechanism.

EXPERIMENTAL APPROACH

Mice were fed either a high fat or chow diet, with or without astaxanthin, for up to 12 weeks. L02 cells were treated with free fatty acids combined with different doses of astaxanthin for 48 h. Histopathology, expression of lipid metabolism, inflammation, apoptosis, and fibrosis-related gene expression were assessed. And the function of mitochondria was also evaluated.

KEY RESULTS

The results indicated that astaxanthin attenuated HFD- and FFA-induced lipid accumulation and its associated oxidative stress, cell apoptosis, inflammation, and fibrosis both in vivo and in vitro. Astaxanthin up-regulated FGF21 and PGC-1α expression in damaged hepatocytes, which suggested an unrecognized mechanism of astaxanthin on ameliorating NAFLD.

CONCLUSION AND IMPLICATIONS

Astaxanthin attenuated hepatocyte damage and mitochondrial dysfunction in NAFLD by up-regulating FGF21/PGC-1α pathway. Our results suggest that astaxanthin may become a promising drug to treat or relieve NAFLD.

Combined cranberry supplementation and weight loss diet in non-alcoholic fatty liver disease: a double-blind placebo-controlled randomized clinical trial

A double-blind placebo-controlled randomised clinical trial was conducted on 41 patients with non-alcoholic fatty liver disease (NAFLD). Participants were randomly allocated to receive either a cranberry supplement or a placebo for 12 weeks. Both groups were assigned to follow a weight loss diet. At the end of the study, alanine aminotransferase and insulin decreased significantly in both groups (p < .05); however, this reduction was significantly greater in the cranberry group than in the placebo group (p < .05). Significant improvements in insulin resistance were observed in the cranberry group and between the two groups (p < .001 and p = .020, respectively). Also, there was an improvement in steatosis grade and anthropometric measurements in both groups (p < .05), and there was no significant difference between the two groups in regard to these factors (p > .05). It seems that 288 mg of cranberry extract might improve managing NAFLD, which is equivalent to 26 g of dried cranberry.

Drug-Induced Steatosis and Steatohepatitis: The Search for Novel Serum Biomarkers Among Potential Biomarkers for Non-Alcoholic Fatty Liver Disease and Non-Alcoholic Steatohepatitis

Drug-induced steatosis (DIS) and drug-induced steatohepatitis (DISH) are two of several types of drug-induced liver injury (DILI). They can be caused by various drugs and may present as acute, potentially lethal disorders or as chronic slowly progressive liver injury. Despite the fact that they are distinct disorders, the slow progressive forms of DIS and DISH are often confused with or misdiagnosed as non-alcoholic fatty liver disease (NAFLD) or non-alcoholic steatohepatitis (NASH), which are much more common and, by definition, not caused by drugs. Currently the only way to identify DIS is via imaging studies or a liver biopsy, while DISH can be identified only through liver biopsy. In addition, diagnosis of either DIS or DISH requires an exhaustive clinical evaluation and comprehensive causality assessment to rule out other possible causes and determine the association with the suspected drug. Furthermore, it is difficult, using existing methods, to monitor the progression of DIS and DISH and to determine the underlying mechanism. Therefore, there is a great unmet need for non-invasive biomarkers that will be able to identify the development of DIS or DISH during drug development and to monitor for progression or regression of the disorder during treatment or following drug discontinuation. Recent developments in the fields of NAFLD and NASH have introduced several novel biomarkers that show promise for the diagnosis, monitoring, and severity assessment of these common diseases. Given the significant overlap in possible underlying mechanisms and histological pattern between NAFLD/NASH and DIS/DISH, these postulated NAFLD and NASH biomarkers may have a potential application to DIS and DISH. This article reviews the existing medical literature and other publically available information pertaining to novel serum biomarkers for NAFLD and NASH, and explores the concurrent identification of these biomarkers for DIS and DISH.

Use of a bioengineered antioxidant in mouse models of metabolic syndrome

Background: Oxidative stress has been implicated in metabolic syndrome (MetS); however, antioxidants such as vitamin E have had limited success in the clinic. This prompts the question of what effects amore potent antioxidant might produce. A prime candidate is the recently developed bioengineered antioxidant, poly(ethylene glycol)-functionalizedhydrophilic carbon clusters (PEG-HCCs), which are capable of neutralizing the reactive oxygen species (ROS) superoxide anion and hydroxyl radical at10⁶/molecule of PEG-HCC. In this project, we tested the potential of PEG-HCCs as a possible therapeutic for MetS.Results: PEG-HCC treatment lessened lipid peroxidation, aspartate aminotransferase levels, non-fastingblood glucose levels, and JNK phosphorylation inob/ob mice. PEG-HCC-treated WT mice had an increased response to insulin by insulin tolerance tests and adecrease in blood glucose by glucose tolerance tests. These effects were not observed in HFD-fed mice, regardless of treatment. PEG-HCCs were observed in the interstitial space of liver, spleen, skeletal muscle, and adipose tissue. No significant difference was shown in gluconeogenesis or inflammatory gene expression between treatment and dietary groups.Expert Opinion: PEG-HCCs improved some parameters of disease possibly due to a resulting increase in peripheral insulin sensitivity. However, additional studies are needed to elucidate how PEG-HCCsare producing these effects.

Symptom-based network classification identifies distinct clinical subgroups of liver diseases with common molecular pathways

BACKGROUND AND OBJECTIVE

Liver disease is a multifactorial complex disease with high global prevalence and poor long-term clinical efficacy and liver disease patients with different comorbidities often incorporate multiple phenotypes in the clinic. Thus, there is a pressing need to improve understanding of the complexity of clinical liver population to help gain more accurate disease subtypes for personalized treatment.

METHODS

Individualized treatment of the traditional Chinese medicine (TCM) provides a theoretical basis to the study of personalized classification of complex diseases. Utilizing the TCM clinical electronic medical records (EMRs) of 6475 liver inpatient cases, we built a liver disease comorbidity network (LDCN) to show the complicated associations between liver diseases and their comorbidities, and then constructed a patient similarity network with shared symptoms (PSN). Finally, we identified liver patient subgroups using community detection methods and performed enrichment analyses to find both distinct clinical and molecular characteristics (with the phenotype-genotype associations and interactome networks) of these patient subgroups.

RESULTS

From the comorbidity network, we found that clinical liver patients have a wide range of disease comorbidities, in which the basic liver diseases (e.g. hepatitis b, decompensated liver cirrhosis), and the common chronic diseases (e.g. hypertension, type 2 diabetes), have high degree of disease comorbidities. In addition, we identified 303 patient modules (representing the liver patient subgroups) from the PSN, in which the top 6 modules with large number of cases include 51.68% of the whole cases and 251 modules contain only 10 or fewer cases, which indicates the manifestation diversity of liver diseases. Finally, we found that the patient subgroups actually have distinct symptom phenotypes, disease comorbidity characteristics and their underlying molecular pathways, which could be used for understanding the novel disease subtypes of liver conditions. For example, three patient subgroups, namely Module 6 (M6, n = 638), M2 (n = 623) and M1 (n = 488) were associated to common chronic liver disease conditions (hepatitis, cirrhosis, hepatocellular carcinoma). Meanwhile, patient subgroups of M30 (n = 36) and M36 (n = 37) were mostly related to acute gastroenteritis and upper respiratory infection, respectively, which reflected the individual comorbidity characteristics of liver subgroups. Furthermore, we identified the distinct genes and pathways of patient subgroups and the basic liver diseases (hepatitis b and cirrhosis), respectively. The high degree of overlapping pathways between them (e.g. M36 with 93.33% shared enriched pathways) indicates the underlying molecular network mechanisms of each patient subgroup.

CONCLUSIONS

Our results demonstrate the utility and comprehensiveness of disease classification study based on community detection of patient network using shared TCM symptom phenotypes and it can be used to other more complex diseases.

Estradiol-mediated regulation of hepatic iNOS in obese rats: Impact of Src, ERK1/2, AMPKα, and miR-221

PURPOSE

This study aimed to investigate in vivo effects of estradiol on the regulation of hepatic inducible nitric oxide synthase (iNOS) expression in the high fat (HF) diet-induced obesity. Also, we aimed to investigate whether activation of the extracellular signal-regulated kinase (ERK1/2), adenosine monophosphate-activated protein kinase (AMPK), Src kinase, and miR-221 is involved in estradiol-mediated regulation of iNOS in the liver of obese male Wistar rats. Male Wistar rats were fed a standard laboratory diet or a HF diet for 10 weeks. Half of HF rats were treated with estradiol intraperitoneally (40 μg/kg), whereas the other half were placebo-treated 24 H before euthanasia. Results show that estradiol treatment of HF rats decreased hepatic iNOS mRNA (P < 0.05) and protein expression (P < 0.01), the protein levels of p65 subunit of nuclear factor κB (P < 0.05) and ERα (P < 0.05), ERK1/2 phosphorylation (P < 0.001), and ERα/Src kinase association (P < 0.05). By contrast, hepatic Src protein level (P < 0.05), AMPKα phosphorylation (P < 0.05), and miR-221 expression (P < 0.05) were increased in HF rats after estradiol treatment. Our results indicate that estradiol in vivo regulates hepatic iNOS expression in obese rats via molecular mechanisms involving ERK1/2, AMPK, Src, and miR-221 signaling.

DNase II activated by the mitochondrial apoptotic pathway regulates RIP1-dependent non-apoptotic hepatocyte death via the TLR9/IFN-β signaling pathway

Cell death, including apoptotic and non-apoptotic cell death, is frequently observed in liver disease. Upon activation of the mitochondrial apoptotic pathway, mitochondria release not only apoptogenic cytochrome c but also mitochondrial DNA (mtDNA) into the cytosol. The impact of DNase II, a lysosomal acid DNase that degrades mtDNA, on hepatocyte death remains unclear. Administration of ABT-737, a Bcl-xL inhibitor, upregulated DNase II activity in murine hepatocyte cell line BNL CL.2 cells and induced apoptosis. In cells treated with DNase II siRNA, ABT-737 led to accumulation of mtDNA in the cytosol and increased expression of interferon (IFN)-β and induction of propidium iodide (PI)-positive cells, in addition to apoptosis. Induced PI-positive cells were suppressed by RIP1 inhibitor, Necrostatin-1, but not by pan-caspase inhibitor, ZVAD-FMK, suggesting non-apoptotic cell death. Both the increase in IFN-β and the induction of non-apoptotic cell death were abolished by administering a TLR9 antagonist, ODN2088, or by the removal of mtDNA from cells with ethidium bromide. Hepatocyte-specific Mcl-1 knockout mice developed hepatocyte apoptosis accompanied by upregulated DNase II activity in their livers. Further knockout of DNase II induced IFN-β expression and RIP1-dependent non-apoptotic hepatocyte death, both of which were suppressed by the administration of ODN2088. Mice fed a high-fat diet (HFD), an obesity-associated fatty liver model, showed increased expression of IFN-β with suppression of DNase II activity in their livers and developed not only hepatocyte apoptosis but also non-apoptotic hepatocyte death. Hepatocyte-specific knockout of DNase II exacerbated HFD-induced non-apoptotic hepatocyte death and liver fibrosis. In conclusion, without DNase II, apoptotic stimulation on hepatocytes induces TLR9-dependent IFN-β production and RIP1-dependent non-apoptotic cell death originating from mtDNA. In fatty livers, DNase II activity is suppressed in contrast to simple inactivation of Bcl-xL or Mcl-1, and both apoptotic and non-apoptotic hepatocyte death can develop, leading to the progression of liver fibrosis.

The Expression of PNPLA3 Polymorphism could be the Key for Severe Liver Disease in NAFLD in Hispanic Population

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) encompasses: fatty liver (SS), steatohepatitis (NASH) with or without fibrosis and cirrhosis. Patatine-like phosphatas in domain 3 (PNPLA3; adiponutrin; SNP rs738409 C/G, M148I) shows anabolic and catabolic activities on lipid metabolism and significant association to fatty liver content; however, I148M demographics and ethnics, as its role with NAFLD have not been fully elucidated.

MATERIAL AND METHODS

PNPLA3 genotyping from peripheral blood DNA by polymerase chain reaction (PCR) and direct sequencing, 211 patients diagnosed with NAFLD including SS, NASH and fibrosis spectrum.

RESULTS

Eighty nine per cent showed the G risk allele [CC: 23 (10.5%), GC: 73 (34.7%), GG 115 (54.7%)], the allele frequency was 77%, NASH (71%), SS (80%) and fibrosis (73%). GG genotype carriers showed 3.8 times (CI 95%: 3.03 - 4.79) of increased risk of steatohepatitis and 2.3 times more (CI 95%: 1.77 ~ 3.23) risk of having liver fibrosis (CC). PNPLA3 (GC, GG) conditioned higher probability of low levels of HDL cholesterol (p < 0.010), SS even in normal weight (p < 0.007), insulin resistance by HOMA (p < 0.029), NAFLD fibrosis score showed > 0.675 (p < 0.001) and altered serum alanine aminotransferase (p < 0.05).

CONCLUSION

PNPLA3 expression in Hispanics could be decisive in NAFLD pathogenesis, it's highly prevalent and it's a key to condition and determine the spectrum associated, SS, NASH and fibrosis.

A Point-based Mortality Prediction System for Older Adults with Diabetes

The mortality prediction models for the general diabetic population have been well established, but the corresponding elderly-specific model is still lacking. This study aims to develop a mortality prediction model for the elderly with diabetes. The data used for model establishment were derived from the nationwide adult health screening program in Taiwan in 2007-2010, from which we applied a 10-fold cross-validation method for model construction and internal validation. The external validation was tested on the MJ health screening database collected in 2004-2007. Multivariable Cox proportional hazards models were used to predict five-year mortality for diabetic patients ≥65 years. A total of 220,832 older subjects with diabetes were selected for model construction, of whom 23,241 (10.5%) died by the end of follow-up (December 31, 2011). The significant predictors retained in the final model included age, gender, smoking status, body mass index (BMI), fasting glucose, systolic and diastolic blood pressure, leukocyte count, liver and renal function, total cholesterol, hemoglobin, albumin, and uric acid. The Harrell's C in the development, internal-, and external-validation datasets were 0.737, 0.746, and 0.685, respectively. We established an easy-to-use point-based model that could accurately predict five-year mortality risk in older adults with diabetes.

Effect of Mediterranean Diet and Antioxidant Formulation in Non-Alcoholic Fatty Liver Disease: A Randomized Study

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide, characterized by liver fatty acid accumulation and fibrosis, not due to excessive alcohol consumption. Notably, nutritional habits have been reported to be implicated in the onset and severity of the hepatic damage, while the Mediterranean diet has shown beneficial effects on NAFLD. Free radicals and oxidative stress were suggested to be involved in the pathogenesis and progression of NAFLD, and several data highlighted the efficacy of antioxidant supplementation in its treatment. The aim of this study was to compare the effects of the Mediterranean diet, with or without an antioxidant complex supplement, in overweight patients suffering from NAFLD. In this prospective study, fifty Caucasian overweight patients were randomized into three groups (Groups A-C). A personalized moderately hypocaloric Mediterranean diet was prescribed to all patients included in the A and B groups. In addition to the diet, Group B was administered antioxidant supplementation daily and for the period of six months. Group C did not have any type of treatment. The study proved that the Mediterranean diet alone or in association with the antioxidant complex improved anthropometric parameters, lipid profile and reduced hepatic fat accumulation and liver stiffness. However, Group B patients, in which the diet was associated with antioxidant intake, showed not only a significant improvement in insulin sensitivity, but also a more consistent reduction of anthropometric parameters when compared with Group A patients. Taken together, these results support the benefit of antioxidant supplementation in overweight patients with NAFLD.

The effects of diet and lifestyle interventions on insulin resistance in patients with nonalcoholic fatty liver disease: a systematic review

Nonalcoholic fatty liver disease (NAFLD) results from excessive fat accumulation in the liver in the absence of excessive alcohol consumption. Insulin resistance (IR) is proposed to be an underlying pathogenic factor in the development and progression of disease. There are currently no proven pharmacotherapies and weight loss is the only prescribed treatment despite a lack of evidence to support a specific diet or lifestyle therapy. The aim of this review is to evaluate the efficacy of dietary lifestyle interventions on IR measured by Homeostasis model assessment in patients with NAFLD. A systematic electronic search of Medline, Scopus, The Cochrane Library, CINAHL and PubMed databases (1999-2015) was performed by two independent reviewers. Randomized control trials evaluating the efficacy of diet and lifestyle interventions on IR in adults diagnosed with NAFLD were included. A total of 6441 articles were identified; eight randomized control trials fulfilled the inclusion criteria. Three studies involved dietary interventions and five incorporated diet and exercise. The majority of intervention groups resulted in significant reductions in IR, with no significant changes observed in the control groups. Lifestyle interventions compared with controls reduced IR measured by homeostasis model assessment. All diet and diet and lifestyle intervention trials were efficient in reducing IR in participants with NAFLD. A lack of literature and variation across interventions warrants the need for extensive research to establish firm dietary lifestyle recommendations.

Prevalence of Nonalcoholic Fatty Liver Disease and its Related Metabolic Risk Factors in Isfahan, Iran

Background:

This study aimed to determine the prevalence of nonalcoholic fatty liver disease (NAFLD) and its related risk factors among the general population of Isfahan city located in the central part of Iran.

Materials and Methods:

In this cross-sectional study, the prevalence of NAFLD among 483 general adult populations was determined using ultrasonography. Anthropometric and biochemical variables were compared in groups with and without NAFLD and their predictive value for occurrence of NAFLD was investigated also.

Results:

Prevalence of NAFLD was 39.3%. Frequency of focal fatty infiltration (FFI), Grade I, Grade II, and Grade III of NAFLD was 9.5%, 21.1%, 7.2%, 1.4%, respectively. Prevalence of different types of NAFLD and FFI, was not different between female and male participants (P = 0.238). Ordinal regression was determined that all of the studied variables have significant predictive value for NAFLD (P < 0.001, γ = 0.615). Spearman correlation indicated that there was a significant relationship between NAFLD and BMI (r = 0.37, P < 0.001), age (r = 0.15, P = 0.001), FBS (r = 0.20, P < 0.001), cholesterol (r = 0.19, P < 0.001), triglyceride (r = 0.20, P < 0.001), LDL (r = 0.16, P < 0.001), AST (r = 0.17, P < 0.001), and ALT (r = 0.31, P < 0.001).

Conclusions:

Considering the high prevalence of NAFLD specially its lower grades among Isfahani adult general population and their association with studied variables, it seems that interventional studies which target-related mentioned risk factors could reduce the overall occurrence of NAFLD.

Liver acoustic radiation force impulse (ARFI) in childhood obesity: comparison and correlation with biochemical markers

PURPOSE

To compare and correlate the diagnostic efficiency of acoustic radiation force impulse (ARFI) elastography with biochemical markers for assessing hepatic changes in overweight and obese children.

METHODS

This prospective study was approved by the institutional ethics committee. It included 54 overweight and obese children and 50 normal children (as a control group) in the age range 5-18 years. For all children, we performed grayscale ultrasonography to diagnose fatty liver, ARFI elastography to measure liver stiffness, and biochemical evaluation for aspartate aminotransferase (AST), alanine aminotransferase (ALT), and serum triglyceride (TG) levels.

RESULTS

Of the 54 obese children, AST was elevated in 13 (24.1%) and ALT was elevated in 16 (29.6%); however, only 4 (25%) of these 16 obese children with abnormal aminotransferase levels had an AST/ALT ratio >0.8. Furthermore, all children with abnormal aminotransferase levels with AST/ALT ratio >0.8 also had abnormal readings of ARFI elastography. The TG was elevated (>150 mg/dL) in 2 out of 54 (3.7%) obese children. None of the normal children showed abnormal levels of aminotransferase and TG. Three out of 54 (5.6%) obese children did not show fatty liver changes, while 29 (53.7%) showed grade-I fatty liver changes, and 22 (40.7%) showed grade-II fatty liver changes. The mean (SD) ARFI value was 1.13 m/s (SD 0.199) for obese children and 1.02 m/s (SD 0.11) for children in the control group. Of the 54 obese children, 49 (90.7%) showed ARFI values of <1.19 m/s (normal), 4 (7.4%) had ARFI values from >1.19 to <1.75 m/s, and 1 (1.9%) had an ARFI value >1.75 m/s. Four children with an increased ARFI value also had an AST/ALT ratio >0.8. However, one obese child with a raised ARFI value did not have an elevated AST/ALT ratio, and none of his aminotransferase levels were abnormal. All normal children had ARFI values <1.19 m/s.

CONCLUSION

ARFI elastography shows excellent correlation with AST/ALT ratios in obese children and may be used as a noninvasive tool to detect nonalcoholic fatty liver disease (NAFLD) and associated hepatic changes, especially in pediatric patients, for whom liver biopsy is not always feasible.

Role of the gastroenterologist in the management of the obese patient

Obesity is a highly prevalent disease worldwide, and one in which gastroenterologists can play an important role. Some digestive diseases are more common in obese patients, and preoperative evaluation may be required in some cases. Additionally, bariatric surgery can lead to digestive complications in the short and long term that require intervention, and endoscopic treatment can be an important factor in weight loss. The aim of this review is to highlight the role of the gastroenterologist in the management of obese patients who are either scheduled for or have undergone surgical or endoscopic treatment for obesity.

Non-alcoholic fatty liver disease and diabetes

Non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes (T2DM) are common conditions that regularly co-exist and can act synergistically to drive adverse outcomes. The presence of both NAFLD and T2DM increases the likelihood of the development of complications of diabetes (including both macro- and micro- vascular complications) as well as augmenting the risk of more severe NAFLD, including cirrhosis, hepatocellular carcinoma and death. The mainstay of NAFLD management is currently to reduce modifiable metabolic risk. Achieving good glycaemic control and optimising weight loss are pivotal to restricting disease progression. Once cirrhosis has developed, it is necessary to screen for complications and minimise the risk of hepatic decompensation. Therapeutic disease modifying options for patients with NAFLD are currently limited. When diabetes and NAFLD co-exist, there are published data that can help inform the clinician as to the most appropriate oral hypoglycaemic agent or injectable therapy that may improve NAFLD, however most of these data are drawn from observations in retrospective series and there is a paucity of well-designed randomised double blind placebo controlled studies with gold-standard end-points. Furthermore, given the heterogeneity of inclusion criteria and primary outcomes, as well as duration of follow-up, it is difficult to draw robust conclusions that are applicable across the entire spectrum of NAFLD and diabetes. In this review, we have summarised and critically evaluated the available data, with the aim of helping to inform the reader as to the most pertinent issues when managing patients with co-existent NAFLD and T2DM.

The Metabolic Syndrome and Its Influence on Nonalcoholic Steatohepatitis

Nonalcoholic steatohepatitis (NASH) and the metabolic syndrome (MetS) are highly prevalent in the Western population. Their pathogenesis is closely linked to insulin resistance, which serves as a therapeutic target for the management of these conditions. This review article reviews the research supporting the influence of MetS on NASH and includes studies supporting their similar epidemiology, pathogenesis, and treatment.

Dietary supplements and pediatric non-alcoholic fatty liver disease: Present and the future

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in children. High prevalence of pediatric obesity and sedentary lifestyle has augmented the incidence of NAFLD in children. Obesity is associated with an increased risk of NAFLD through various mechanisms such as intensification of insulin resistance and increased levels of inflammatory markers. There is no approved medical intervention for treatment of pediatric NAFLD; the only proven strategy in management of pediatric NAFLD is lifestyle modification. Recently, the effects of nutritional supplements have been examined in the management of pediatric NAFLD. The purpose of this review is to summarize the studies evaluating the effects of nutritional supplements on pediatric NAFLD and explain the future direction in this field.

Targeting fatty acid metabolism to improve glucose metabolism

Disturbances in fatty acid metabolism in adipose tissue, liver, skeletal muscle, gut and pancreas play an important role in the development of insulin resistance, impaired glucose metabolism and type 2 diabetes mellitus. Alterations in diet composition may contribute to prevent and/or reverse these disturbances through modulation of fatty acid metabolism. Besides an increased fat mass, adipose tissue dysfunction, characterized by an altered capacity to store lipids and an altered secretion of adipokines, may result in lipid overflow, systemic inflammation and excessive lipid accumulation in non-adipose tissues like liver, skeletal muscle and the pancreas. These impairments together promote the development of impaired glucose metabolism, insulin resistance and type 2 diabetes mellitus. Furthermore, intrinsic functional impairments in either of these organs may contribute to lipotoxicity and insulin resistance. The present review provides an overview of fatty acid metabolism-related pathways in adipose tissue, liver, skeletal muscle, pancreas and gut, which can be targeted by diet or food components, thereby improving glucose metabolism.

Rimonabant Improves Oxidative/Nitrosative Stress in Mice with Nonalcoholic Fatty Liver Disease

The present study deals with the effects of rimonabant on oxidative/nitrosative stress in high diet- (HFD-) induced experimental nonalcoholic fatty liver disease (NAFLD). Male mice C57BL/6 were divided into the following groups: control group fed with control diet for 20 weeks (C; n = 6); group fed with HFD for 20 weeks (HF; n = 6); group fed with standard diet and treated with rimonabant after 18 weeks (R; n = 9); group fed with HFD and treated with rimonabant after 18 weeks (HFR; n = 10). Daily dose of rimonabant (10 mg/kg) was administered to HFR and R group by oral gavage for two weeks. Treatment induced a decrease in hepatic malondialdehyde concentration in HFR group compared to HF group (P < 0.01). The concentration of nitrites + nitrates in liver was decreased in HFR group compared to HF group (P < 0.01). Liver content of reduced glutathione was higher in HFR group compared to HF group (P < 0.01). Total liver superoxide dismutase activity in HFR group was decreased in comparison with HF group (P < 0.01). It was found that rimonabant may influence hepatic iron, zinc, copper, and manganese status. Our study indicates potential usefulness of cannabinoid receptor type 1 blockade in the treatment of HFD-induced NAFLD.

Nonalcoholic steatohepatitis associated with metabolic syndrome: relationship to insulin resistance and liver histology

BACKGROUND

Nonalcoholic steatohepatitis (NASH) is a hepatic manifestation of metabolic syndrome. We aimed to assess the relationship of metabolic syndrome-associated NASH and insulin resistance (IR), and to define the correlation of chemicometabolic components with different degree of liver histology in NASH subjects.

STUDY

Ninety-four subjects with NASH (mean age, 38±14 y; 77% male) were enrolled. IR was calculated using a homeostasis model assessment of insulin resistance (HOMA-IR). Clinical characteristics including IR and accompanying metabolic risk components in NASH subjects were compared with those of 52 diabetics and 21 healthy controls. The relationship between IR and chemicometabolic variables was analyzed according to different clustering of metabolic risk components and the histologic activity.

RESULTS

NASH subjects had a stronger association with metabolic syndrome than healthy controls. HOMA-IR was significantly higher in NASH subjects than in healthy controls (4.4±2.5 vs. 1.7±0.6; P<0.001) but not than in diabetics. NASH subjects with metabolic syndrome were more likely to have higher HOMA-IR compared with that of NASH subjects without metabolic syndrome (5.0±2.9 vs. 3.6±1.7; P=0.032). HOMA-IR showed a positive correlation with body mass index (r=0.428, P=0.015) and serum fasting blood sugar (r=0.365, P=0.037). Serum aspartate aminotransferase/alanine aminotransferase ratio (P=0.029) and high-density lipoprotein cholesterol level (P=0.034) were significantly affected according to the degree of fibrotic activity in 41 histology-proven NASH subjects.

CONCLUSIONS

NASH subjects showed increased IR with a significant association of metabolic syndrome. The severity of hepatic fibrosis revealed a strong correlation with serum aspartate aminotransferase/alanine aminotransferase ratio and high-density lipoprotein cholesterol level.

Reactive oxygen and nitrogen species in steatotic hepatocytes: a molecular perspective on the pathophysiology of ischemia-reperfusion injury in the fatty liver

SIGNIFICANCE

Hepatic ischemia-reperfusion (IR) injury results from the temporary deprivation of hepatic blood supply and is a common side effect of major liver surgery (i.e., transplantation or resection). IR injury, which in most severe cases culminates in acute liver failure, is particularly pronounced in livers that are affected by non-alcoholic fatty liver disease (NAFLD). In NAFLD, fat-laden hepatocytes are damaged by chronic oxidative/nitrosative stress (ONS), a state that is acutely exacerbated during IR, leading to extensive parenchymal damage.

RECENT ADVANCES

NAFLD triggers ONS via increased (extra)mitochondrial fatty acid oxidation and activation of the unfolded protein response. ONS is associated with widespread protein and lipid (per)oxidation, which reduces the hepatic antioxidative capacity and shifts the intracellular redox status toward an oxidized state. Moreover, activation of the transcription factor peroxisome proliferator-activated receptor α induces expression of mitochondrial uncoupling protein 2, resulting in depletion of cellular energy (ATP) reserves. The reduction in intracellular antioxidants and ATP in fatty livers consequently gives rise to severe ONS and necrotic cell death during IR.

CRITICAL ISSUES

Despite the fact that ONS mediates both NAFLD and IR injury, the interplay between the two conditions has never been described in detail. An integrative overview of the pathophysiology of NAFLD that renders steatotic hepatocytes more vulnerable to IR injury is therefore presented in the context of ONS.

FUTURE DIRECTIONS

Effective methods should be devised to alleviate ONS and the consequences thereof in NAFLD before surgery in order to improve resilience of fatty livers to IR injury.

Grading scale of visceral adipose tissue thickness and their relation to the nonalcoholic fatty liver disease

CONTEXT

The mesenteric fat is drained by the portal system, being related to the metabolic syndrome which is an impor-tant risk factor for non-alcoholic fatty liver disease (NAFLD).

OBJECTIVES

Graduate of visceral fat thickness and correlate with the NAFLD degree through ultrasonography method.

METHODS

We studied 352 subjects for age, gender, measures of subcutaneous fat thickness and visceral fat thickness as well as the presence and degree of liver fatty. Was analyzed the independent relationship between visceral fat thickness and NAFLD, and linear regression analysis was used in order to predict the visceral fat thickness from subcutaneous fat thickness.

RESULTS

The mean age of 225 women (63.9%) and 127 men (36.1%) was 47.5 ± 14.0 (18-77) years, 255 subjects had normal examinations, 97 had NAFLD thus distributed, 37 grade 1, 32 grade 2, and 28 grade 3. The subcutaneous fat thickness ranged from 0.26 to 3.50 cm with a mean of 1.3 ± 0.6 cm and visceral fat thickness ranged from 0.83 to 8.86 cm with a mean of 3.6 ± 1.7 cm. Linear regression showed that for every increase of 1 cm in subcutaneous fat thickness the visceral fat thickness will increase 0.9 cm.

CONCLUSIONS

The visceral fat thickness measured by ultrasonography is a useful and seems to be able to help estimate the risk of NAFLD.

Effects of resveratrol and other polyphenols in hepatic steatosis

Non-alcoholic fatty liver disease covers a wide spectrum of liver pathologies which range from simple steatosis to non-alcoholic steatohepatitis. Polyphenols are members of a very large family of plant-derived compounds that can have beneficial effects on human health, and thus their study has become an increasingly important area of human nutrition research. The aim of the present review is to compile published data concerning the effects of both isolated polyphenols as well as polyphenol extracts, on hepatocyte and liver fat accumulation under different steatosis-inducing conditions. The results reported clearly show that this group of biomolecules is able to reduce fat accumulation, but further studies are needed to establish the optimal dose and treatment period length. With regard to the potential mechanisms of action, there is a good consensus. The anti-lipidogenic effect of polyphenols is mainly due to reduced fatty acid and triacylglycerol synthesis, increased in fatty acid oxidation, and reduced of oxidative stress and inflammation. As a general conclusion, it can be stated that polyphenols are biomolecules which produce hepatoprotective effects. To date, these beneficial effects have been demonstrated in cultured cells and animal models. Thus, studies performed in humans are needed before these molecules can be considered as truly useful tools in the prevention of liver steatosis.

Impact of glucose tolerance on the severity of non-alcoholic steatohepatitis

Aims/Introduction:  We investigated the relationship between non‐alcoholic steatohepatitis (NASH) and different stages of fasting plasma glucose (FPG) concentrations, and the association between factors related to glucose tolerance and severity of NASH.

Materials and Methods:  A total of 147 patients with non‐alcoholic fatty liver disease (NAFLD) who had undergone a liver biopsy were divided into three groups: a normal glucose tolerance (NGT) group, an impaired fasting glucose (IFG) group and a diabetes (DM) group. In addition, to investigate progression factors of NASH in the DM group, we divided the diabetic patients into two groups: a group with NASH (NASH group) and a group without NASH, the simple steatosis (SS) group. The relationship between the patients’ clinical parameters and the severity of NAFLD/NASH were analyzed.

Results:  In the patients with liver biopsies, the IFG group had the highest percentage of NASH. There was no correlation between FPG and either total NAFLD activity scores (NAS) or staging of NASH, but the fasting serum insulin was correlated significantly with both, even after adjusting for age, sex and body mass index. Among the diabetic patients, the fasting insulin values in the NASH group were significantly higher than in the SS group, but there were no differences in FPG or A1c values between the two groups. The fasting serum insulin correlated significantly with total NAS, but the FPG and A1c values did not.

Conclusions:  A high percentage of the IFG group developed NASH. Hyperinsulinemia, but not hyperglycemia, was associated with severity of NASH. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00134.x, 2011)

Central obesity and altered peripheral adipose tissue gene expression characterize the NAFLD patient with insulin resistance: Role of nutrition and insulin challenge

OBJECTIVE

Insulin resistance (IR) and white adipose tissue (WAT) dysfunction frequently are associated with nonalcoholic fatty liver disease (NAFLD); however, the pathogenic mechanisms contributing to their clustering are not well defined. The aim of this study was to define some nutritional, anthropometric, metabolic, and genetic mechanisms contributing to their clustering.

METHODS

Forty-five (20 men, 25 women) patients (age 45.7 ± 11.1 y) with recent diagnosis of NAFLD were grouped according to IR state. Energy balance was assessed using a food questionnaire and indirect calorimetry, and body composition with anthropometry and dual-energy x-ray absorptiometry. Biochemical and hormonal parameters combined with adipose tissue gene expression were determined. Microarray analysis of gene expression was performed in a subset of WAT samples from IR patients (n = 9), in the fasted state, after specific test meals (monounsaturated fatty acid [MUFA], saturated fat [SAT], and carbohydrate-rich) and after being challenged with insulin.

RESULTS

IR patients exhibited higher trunk fat to leg fat ratio (P < 0.05) and had a higher ratio of SAT/MUFA fat intake (P < 0.05) than insulin-sensitive (IS) individuals. Deposition of fat in the trunk but not in the leg was directly related to liver enzyme levels (P < 0.05). IR patients also had lower adiponectin serum levels and leptin (LEP) mRNA expression in WAT compared with IS patients (P < 0.01 and P < 0.05, respectively). Microarray analysis after insulin challenge confirmed that insulin treatment induces the expression of PPARG gene and LEP and decreases GCGR gene (P < 0.05 for all) in WAT. No changes in these genes were observed in the postprandial state induced after the acute effect of specific diets.

CONCLUSIONS

Patients exhibiting NAFLD and IR had preferential central fat deposition directly related to their serum alanine aminotransferase levels. These patients showed peripheral adipose tissue dysfunction and exhibited inappropriately low LEP biosynthesis that could be partially restored after anabolic conditions induced by insulin signaling.

Increased soluble CD36 is linked to advanced steatosis in nonalcoholic fatty liver disease

BACKGROUND

Soluble CD36 (sCD36) clusters with insulin resistance, but no evidence exists on its relationship with hepatic fat content. We determined sCD36 to assess its link to steatosis in nonalcoholic fatty liver disease (NAFLD) and chronic hepatitis C (CHC) patients.

MATERIALS AND METHODS

Two hundred and twenty-seven NAFLD, eighty-seven CHC, and eighty-five patients with histologically normal liver (NL) were studied. Steatosis was graded by Kleiner's histological scoring system. Serum sCD36 and hepatic CD36 expression was assessed by immunoassay and immunohistochemistry, respectively.

RESULTS

In NAFLD, serum sCD36 levels were significantly higher in simple steatosis than in NL (361.4 ± 286.4 vs. 173.9 ± 137.4 pg/mL, respectively; P < 0.001), but not in steatohepatitis (229.6 ± 202.5 pg/mL; P = 0.153). In CHC, serum sCD36 levels were similar regardless of the absence (428.7 ± 260.3 pg/mL) or presence of steatosis (387.2 ± 283.6 pg/mL; P = 0.173). A progressive increase in serum sCD36 values was found in NAFLD depending on the histological grade of steatosis (P < 0.001), but not in CHC (P = 0.151). Serum sCD36 concentrations were independently associated with advanced steatosis in NAFLD when adjusted by demographic and anthropometric features [odds ratio (OR), 1.001; 95% confidence interval (CI), 1.000 to 1.002; P = 0.021] and by metabolic variables (OR, 1.002; 95% CI, 1.000 to 1.003; P = 0.001). Interestingly, a significant correlation was observed between hepatic CD36 and serum sCD36 (ρ = 0.499, P < 0.001).

CONCLUSIONS

Increased serum sCD36 is an independent factor associated with advanced steatosis in NAFLD.

Therapy of experimental NASH and fibrosis with galectin inhibitors

Non-alcoholic steatohepatitis (NASH) and resultant liver fibrosis is a major health problem without effective therapy. Some data suggest that galectin-3 null mice are resistant to the development of NASH with fibrosis. We examined the ability of two complex carbohydrate drugs that bind galectin-3, GM-CT-01 and GR-MD-02, to treat NASH with fibrosis in a murine model. GR-MD-02 treatment resulted in marked improvement in liver histology with significant reduction in NASH activity and collagen deposition. Treatments seemed also to improve both glomerulopathy and interstitial fibrosis observed in kidneys. The improvement in liver histology was evident when animals were treated early in disease or after establishment of liver fibrosis. In all measures, GM-CT-01 had an intermediate effect between vehicle and GR-MD-02. Galectin-3 protein expression was increased in NASH with highest expression in macrophages surrounding lipid laden hepatocytes, and reduced following treatment with GR-MD-02, while the number of macrophages was unchanged. Treatment with GR-MD-02 also reduced the expression of pathological indicators including iNOS, an important TH1 inflammatory mediator, CD36, a scavenger receptor for lipoproteins on macrophages, and α-smooth muscle actin, a marker for activated stellate cells which are the primary collagen producing cells in liver fibrosis. We conclude that treatment with these galectin-3 targeting drugs improved histopathological findings of NASH and markedly reduced fibrosis in a murine model of NASH. While the mechanisms require further investigation, the treatment effect is associated with a reduction of galectin-3 expressed by activated macrophages which was associated with regression of NASH, including hepatocellular fat accumulation, hepatocyte ballooning, intra-portal and intra-lobular inflammatory infiltrate, and deposition of collagen. Similar effects were found with GM-CT-01, but with approximately four-fold lower potency than GR-MD-02. The results, in combination with previous experiments in toxin-induced fibrosis, suggest that these galectin-targeting drugs may have potential in human NASH with fibrosis.

Nonalcoholic Fatty liver: a possible new target for type 2 diabetes prevention and treatment

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder worldwide. Several lines of evidence have indicated a pathogenic role of insulin resistance, and a strong association with type 2 diabetes (T2MD) and metabolic syndrome. Importantly, NAFLD appears to enhance the risk for T2MD, as well as worsen glycemic control and cardiovascular disease in diabetic patients. In turn, T2MD may promote NAFLD progression. The opportunity to take into account NAFLD in T2MD prevention and care has stimulated several clinical studies in which antidiabetic drugs, such as metformin, thiazolidinediones, GLP-1 analogues and DPP-4 inhibitors have been evaluated in NAFLD patients. In this review, we provide an overview of preclinical and clinical evidences on the possible efficacy of antidiabetic drugs in NAFLD treatment. Overall, available data suggest that metformin has beneficial effects on body weight reduction and metabolic parameters, with uncertain effects on liver histology, while pioglitazone may improve liver histology. Few data, mostly preclinical, are available on DPP4 inhibitors and GLP-1 analogues. The heterogeneity of these studies and the small number of patients do not allow for firm conclusions about treatment guidelines, and further randomized, controlled studies are needed.

Markers in nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD), the most common liver disorder worldwide, encompasses a spectrum of abnormal liver histology ranging from simple steatosis to nonalcoholic steatohepatitis (NASH) and cirrhosis. Population studies show that NAFLD is strongly associated with insulin resistance, obesity, type 2 diabetes mellitus, and lipid abnormalities. In the context of hepatic steatosis, factors that promote cell injury, inflammation, and fibrosis include oxidative stress, early mitochondrial dysfunction, endoplasmic reticulum stress, iron accumulation, apoptosis, adipocytokines, and stellate cell activation. The exact NASH prevalence is unknown because of the absence of simple noninvasive diagnostic tests. Although liver biopsy is the "gold standard" for the diagnosis of NASH, other tests are needed to facilitate the diagnosis and greatly reduce the requirement for invasive liver biopsy. In addition, the development of new fibrosis markers in NASH is needed to facilitate the assessment of its progression and the effectiveness of new therapies. The aim of this chapter, which is overview of biomarkers in NASH, is to establish a systematic approach to laboratory findings of the disease.

Evolution of nonalcoholic fatty liver disease recurrence after liver transplantation

Nonalcoholic steatohepatitis (NASH) is the progressive form of nonalcoholic fatty liver disease (NAFLD) and is the fourth most common indication for liver transplantation. Risk factors for NAFLD can persist and even worsen after liver transplantation. However, the risk and significance of NAFLD recurrence remain unclear. Reported posttransplant NAFLD and NASH recurrence rates vary widely across studies. There is little information detailing the histological evolution of NAFLD recurrence, and the long-term natural history of NAFLD recurrence is unclear. In this review, we summarize the findings of studies on the prevalence of recurrent NAFLD and its risk factors in the posttransplant setting, and we explore reasons for the discrepant reported recurrence rates. On the basis of currently available data, the relatively low rates of advanced fibrosis and NAFLD-associated graft loss and the comparability of the survival rates for these patients and patients undergoing transplantation for other diseases suggest that although NAFLD or NASH can recur, the clinical significance of disease recurrence for graft or patient survival may be small.

Ultrasonography (US) and non-invasive diagnostic methods for non-alcoholic fatty liver disease (NAFLD) and early vascular damage. Possible application in a population study on the metabolic syndrome (MS)

Abdominal ultrasonography (US) represents the first-line imaging examination in chronic liver diseases; in most cases, US, laboratory findings and the clinical context are generally sufficient to guide the diagnosis. Thanks to the considerable diffusion of US, we have seen an increased diagnosis of NAFLD in recent years, although this condition is generally silent from a clinical point of view. We have to identify the metabolic syndrome in the general population and to promptly recognize NAFLD to prevent its development into non-alcoholic steatohepatitis, cirrhosis and hepatocellular carcinoma. Among the non-invasive diagnostic techniques for NAFLD and for early vascular damage, ultrasonography represents the method of choice. In fact, besides the traditional semiotics of fundamental US of the liver, new US techniques have recently been proposed (contrast enhancement US, acoustic structure characterization), with respect to serum biomarkers and Fibroscan, for the study of liver fibrosis. Similarly, also as concerns the US measurement of carotid intima-media thickness, new automated methods with sophisticated software and radio-frequency signal have recently been introduced. Finally, we report the preliminary results of a personal experience on liver and carotid US in the epidemiology of the metabolic syndrome.

Nonalcoholic fatty liver disease of two ethnic groups in Kuwait: comparison of prevalence and risk factors

OBJECTIVES

To assess the prevalence of nonalcoholic hepatic steatosis (nonalcoholic fatty liver disease, NAFLD) and the significance of some risk factors, such as obesity and glucose metabolism impairment, for two major ethnic groups of Kuwait: Arabs and South Asians.

SUBJECTS AND METHODS

143 adults (Arab: n = 81; South Asian: n = 62) were enrolled in the study. Anthropometric measurements including body mass index (BMI), waist circumference (WC), hip circumference (HC) and waist-to-hip ratio were performed along with abdominal ultrasonography. The prevalence of liver steatosis was assessed; its relation to glucose metabolism impairment, obesity, age and gender was compared in the two ethnic groups.

RESULTS

Except for waist-to-hip ratio, the anthropometric parameters were higher in Arabs than South Asians. The respective parameters in Arabs and South Asians were: BMI: 30.9 ± 6.6 versus 27.0 ± 4.5, p < 0.001; WC: 101.5 ± 16.4 versus 94.0 ± 12.2, p = 0.002; HC: 106.6 ± 12.4 versus 99.2 ± 9.9, p < 0.001. Although Arabs were more obese, they did not exhibit a higher prevalence of steatosis (33.3 vs. 29.0%, p = 0.583). According to multivariate analysis, only gender (odds ratio 3.93, p = 0.005), glucose metabolism impairment (odds ratio 4.94, p = 0.003) and WC (odds ratio 4.75, p = 0.012) remained significantly associated with steatosis.

CONCLUSION

No significant difference in NAFLD prevalence was found between Arabs and South Asians. Only gender, history of impaired glucose metabolism and abdominal obesity expressed by WC had an independent predictive value for developing liver steatosis.

Effects of moderate red wine consumption on liver fat and blood lipids: a prospective randomized study

BACKGROUND

There have been no human prospective randomized studies of the amount of alcohol that can induce hepatic steatosis.

METHODS

Thirty-two healthy women and twelve healthy men (34 ± 9 years of age) were randomized to consume 150 ml of red wine/day for women (16 g ethanol/day) or double that amount for men (33 g ethanol/day), or to alcohol abstention for 90 days. Participants underwent proton-nuclear magnetic-resonance spectroscopy for measurement of hepatic triglyceride content (HTGC). Blood samples for assessment of cardiovascular risk were drawn before and after the intervention.

RESULTS

After exclusion of three subjects with steatosis at baseline a trend towards increased HTGC was apparent for red wine (before median: 1.1%, range 0.2-3.9%, after median: 1.1%, range 0.5-5.2 %, P = 0.059) a difference that was statistically significant compared with abstainers (p = 0.02). However, no subject developed hepatic steatosis. Low-density lipoprotein (LDL)-cholesterol was lowered by red wine (-0.3 mmol/l, SE -0.1, 95% CI -0.6 to -0.04).

CONCLUSIONS

Moderate consumption of red wine during three months increased HTGC in subjects without steatosis at baseline. However, since not a single participant developed steatosis we suggest that the threshold of alcohol consumption to define nonalcoholic fatty liver disease should not be lower than the amount in our study.

Mechanisms and implications of age-related changes in the liver: nonalcoholic Fatty liver disease in the elderly

Nonalcoholic fatty liver disease (NAFLD) is hepatic steatosis associated with metabolic abnormalities such as overweight/central obesity, insulin resistance, type 2 diabetes (T2D), and dyslipidemia. NAFLD is becoming the most common liver disease in contemporary society, with the highest prevalence in those over 60 years. NAFLD pathology ranges from simple steatosis to a necroinflammatory fibrosing disorder called steatohepatitis (SH), the latter associated with high risk of developing cirrhosis, often occuring in the seventh to ninth decades of life. While the main health implications of NAFLD are increased risk of developing T2D, cardiovascular diseases, and common cancers, there is substantantially increased standardized mortality, and deaths from decompensated cirrhosis and hepatocellular carcinoma (HCC). Little is known about the interactive effects of ageing and NAFLD, with most studies focusing on the younger population. This paper summarises the epidemiology, pathogenesis, and clinical course of NAFLD, with particular attention to persons over age 60 years. An approach to the management of NASH and its complications in the elderly, will also be presented here.

Presence and significance of microvesicular steatosis in nonalcoholic fatty liver disease

BACKGROUND & AIMS

Liver biopsies from patients with nonalcoholic fatty liver disease (NAFLD) sometimes exhibit non-zonal aggregates of hepatocytes with microvesicular steatosis, but its prevalence and significance are unclear. In this study, we have evaluated the frequency of microvesicular steatosis and assessed its association with histological markers of disease severity in a large sample of NAFLD liver biopsies.

METHODS

Liver biopsies from a large cohort of adults who participated in two studies conducted by the NASH Clinical Research Network (NASH CRN) were included in this cross-sectional study. Liver histology was assessed centrally and various histological features scored in a systematic fashion. The relationship between microvesicular steatosis and various histological features that characterize NAFLD was tested by multiple logistic regression, after controlling for age, gender, race, body mass index, and diabetes.

RESULTS

Among 1022 liver biopsies included, 102 (10%) had microvesicular steatosis. No demographic differences were noted between patients with or without microvesicular steatosis. The presence of microvesicular steatosis was associated with higher grades of steatosis (p<0.001), ballooning cell injury (p<0.001), presence of Mallory-Denk bodies (p<0.007), presence of megamitochondria (p<0.0001), higher NAS scores (p<0.0001), more advanced fibrosis (p<0.0001), and diagnosis of borderline or definite NASH (p<0.0001).

CONCLUSIONS

Microvesicular steatosis correlates with more advanced histology of NAFLD. Longitudinal studies are needed to address the role of microvesicular steatosis in mediating cellular injury and disease progression in NAFLD.

Obesity, Visceral Fat, and NAFLD: Querying the Role of Adipokines in the Progression of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) represents a spectrum of clinicopathologic conditions ranging from steatosis alone to nonalcoholic steatohepatitis (NASH), with varying risks for progression to cirrhosis and hepatocellular carcinoma. There is mounting evidence that NAFLD not only complicates obesity, but also perpetuates its metabolic consequences. Critical event that leads to progressive liver injury in NAFLD is unknown. Obesity reflects a generalized proinflammatory state with its increased inflammatory markers like C reactive protein, IL-6, IL-8, IL-10, PAI-1, TNF-α, and hepatocyte growth factor. The elevated production of these adipokines is increasingly considered to be important in the development of diseases linked to obesity and the metabolic syndrome. Disordered cytokine production is likely to play a role in the pathogenesis of NAFLD. There is no effective treatment for NAFLD, though weight loss may halt disease progression and revert histological changes, the underlying mechanism remaining elusive. All stages of the disease pathway from prevention, early identification/diagnosis, and treatment require an understanding of the pathogenesis of liver injury in NAFLD.

The effect of the Spanish Ketogenic Mediterranean Diet on nonalcoholic fatty liver disease: a pilot study

The "Spanish Ketogenic Mediterranean Diet" (SKMD) has been shown to be an effective and safe way to cure patients suffering from metabolic syndrome (MS). Keeping in mind that nonalcoholic fatty liver disease (NAFLD) is closely associated with MS, the purpose of this study was to evaluate the potential therapeutic properties under free living conditions of the SKMD in patients with MS (following the International Diabetes Federation [IDF] consensus guidelines) and NAFLD (suspected by using a cutoff value of alanine aminotransferase [ALT] levels of >40 U/L and confirmed by abdominal ultrasonography) over a 12-week period. A prospective study was carried out in 14 obese men meeting the inclusion criteria and whose body mass index (BMI) and age were 36.58±0.54 kg/m² and 41.18±2.28 years, respectively. Statistical differences between the parameters studied before and after administration of the SKMD (week 0 and 12) were analyzed by paired Student's t test (continuous variables) and the χ² test (discontinuous variables). P<.05 was considered statistically significant. There was an extremely significant (P<.001) improvement in body weight (from 109.79 kg to 95.86 kg), low-density lipoprotein-cholesterol (from 123.43 mg/dL to 100.35 mg/dL), ALT (from 71.92 U/L to 37.07 U/L), aspartate aminotransferase (from 47.71 U/L to 29.57 U/L), steatosis degree (complete fatty liver regression was observed in 21.4% of the patients, and an overall reduction was found in 92.86% of the patients), and all the parameters studied associated with the MS: BMI (from 36.99 kg/m² to 32.42 kg/m²), waist circumference (from 114.01 cm to 98.59 cm), fasting plasma glucose (from 118.57 mg/dL to 90.14 mg/dL), triacylglycerols (from 232.64 mg/dL to 111.21 mg/dL), high-density lipoprotein-cholesterol (HDLc) (from 42.81 mg/dL to 58.71 mg/dL), systolic blood pressure (from 142.86 mm Hg to 125.36 mm Hg), and diastolic blood pressure (from 89.64 mm Hg to 77.86 mm Hg). After the diet all the subjects were free of MS according to the IDF definition, and 100% of them had normal triacylglycerols and HDLc levels, in spite of the fact that 100% of them still had a BMI of >30 kg/m². We conclude that the SKMD could be an effective and safe way to treat patients suffering from MS and the associated NAFLD.

Role of the inducible nitric oxide synthase in the onset of fructose-induced steatosis in mice

To test the hypothesis that the inducible nitric oxide synthase (iNOS) is involved in mediating the toll-like receptor 4-dependent effects on the liver in the onset of fructose-induced steatosis, wild-type and iNOS knockout (iNOS(-/-)) mice were either fed tap water or 30% fructose solution for 8 weeks. Chronic consumption of 30% fructose solution led to a significant increase in hepatic steatosis and inflammation as well as plasma alanine-aminotransferase levels in wild-type mice. This effect of fructose feeding was markedly attenuated in iNOS(-/-) mice. Hepatic lipidperoxidation, concentration of phospho-IκB, nuclear factor κB activity, and tumor necrosis factor-α mRNA level were significantly increased in fructose-fed wild-type mice, whereas in livers of fructose-fed iNOS(-/-) mice, lipidperoxidation, phospho-IκB, nuclear factor κB activity, and tumor necrosis factor-α expression were almost at the level of controls. However, portal endotoxin levels and hepatic myeloid differentiation factor 88 expression were significantly higher in both fructose-fed groups compared to controls. Taken together, these data suggest that (i) the formation of reactive oxygen species in liver is a key factor in the onset of fatty liver and (ii) iNOS is involved in mediating the endotoxin/toll-like receptor 4-dependent effects in the development of fructose-induced fatty liver.

Liver fibrogenesis and metabolic factors

Mechanisms of liver fibrosis are complex and varied. Among them, metabolic factors are particularly important in the development of fibrosis associated with nonalcoholic steatohepatitis (NASH). These factors are some of the "multiple parallel hits" responsible for liver damage during NASH. Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome. Major profibrogenic protagonists, such as hepatic stellate cells and Kupffer cells, are activated by insulin resistance, apoptosis and local inflammation. Relations between steatosis, insulin resistance and fibrosis are complex. Initially, simple steatosis may be a way to store deleterious free fatty acid in neutral triglycerides. If the lipid storage threshold is exceeded, steatosis may become associated with lipotoxicity. Similarly, interindividual variations of adipose tissue expandability might explain various phenotypes, ranging from "metabolically obese patients with normal weight" to "metabolically normal morbidly obese patients". The metabolic abnormalities in subcutaneous and visceral adipose tissue are insulin resistance and low-grade inflammation, which are associated with increased release of free fatty acid flux and changes in adipocytokines production such as leptin, adiponectin and interleukin 6. The nuclear transcription factor peroxisome proliferator-activated receptor gamma (PPARγ) and the endocannabinoid system might have important roles in liver fibrogenesis and are potential therapeutic targets. Finally, with the development of new molecular tools, gut microbiota has been recently identified for its pleiotropic functions, including metabolism regulation. Better knowledge of these mechanisms should lead to new strategies for the treatment of metabolic factors that play a key role in liver injuries.

Serum ferritin is a discriminant marker for both fibrosis and inflammation in histologically proven non-alcoholic fatty liver disease patients

INTRODUCTION

Differentiation between steatosis and non-alcoholic steatohepatitis (NASH) in non-alcoholic fatty liver disease (NAFLD) is important as NASH progress to cirrhosis. No specific laboratory/imaging technique exists either to diagnose NASH or to select patients for liver biopsy.

PATIENTS AND METHODS

We evaluated serum ferritin and the features of metabolic syndrome with respect to histological inflammation and/or fibrosis in NAFLD patients. The Kleiner scoring system was used to classify NAFLD in consecutive liver biopsies. One hundred and eleven patients: median age 52.6, 64 males, obesity 62, diabetes mellitus (DM) 58, arterial hypertension 26 and hyperlipidaemia 40%.

RESULTS

Histologically, 40.7 had fatty liver, 30.6% had borderline NASH, 28.7% had NASH and 11% had cirrhosis. Multivariate regression showed that diabetes, serum ferritin concentrations, body mass index (BMI) and AST were independently associated with NASH: together, the areas under the receiver operating characteristic (AUROC) was 0.91 (95% confidence interval 0.86-0.96); fibrosis was associated with ferritin concentrations and BMI: AUROC 0.87, portal inflammation with ferritin and DM: AUROC 0.82, while lobular inflammation was associated with BMI, DM and ferritin: AUROC 0.85.

CONCLUSION

Serum ferritin concentrations and BMI are strongly associated with fibrosis, portal and lobular inflammation in NAFLD patients. Both ferritin and BMI are potential discriminant markers to select patients for liver biopsy and are associated with inflammation and fibrosis.

Inflammation in nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) describes a range of disorders characterized by excess accumulation of triglyceride within the liver. While simple steatosis may be clinically stable, nonalcoholic steatohepatitis (NASH) can be progressive. Inflammation is believed to be the driving force behind NASH and the progression to fibrosis and subsequent cirrhosis. This article will review and interpret the current literature in an attempt to expand our understanding of the environmental and genetic causes of inflammation and its effects in NAFLD.

Eicosapentaenoic acid attenuates progression of hepatic fibrosis with inhibition of reactive oxygen species production in rats fed methionine- and choline-deficient diet

BACKGROUND AND AIMS

Nonalcoholic steatohepatitis (NASH) is associated with fat accumulation in the liver, and develops to cirrhosis with the progression of hepatic fibrosis. Eicosapentaenoic acid (EPA) is used to treat hyperlipidemia, and suppresses hepatic fat accumulation. As the effect of EPA on NASH remains unclear, we assessed the therapeutic effect of EPA and its mechanisms in an animal model of NASH.

METHODS

Wistar rats were fed a methionine- and choline-deficient (MCD) diet for 20 weeks, and given EPA ethyl ester (EPA-E, 1,000 mg/kg/day) or vehicle by gavage from week 12, at which hepatic fibrosis has already established. The liver was histologically analyzed for fibrosis and α-smooth muscle actin (αSMA) expression, and hepatic levels of transforming growth factor-β1 (TGF-β1), fibrogenic gene expression, reactive oxygen species (ROS), and triglyceride (TG) content were determined. Serum oxidative markers were also measured.

RESULTS

EPA-E treatment significantly suppressed the MCD-induced increase in fibrotic area of liver sections, with repressed macronodule formation. EPA-E also suppressed increases in hepatic fibrogenic factors, αSMA expression, TGF-β1 level, and messenger RNA (mRNA) levels of procollagens and connective tissue growth factor. EPA-E reduced MCD-induced increases in hepatic ROS level, serum oxidative markers, 8-isoprostane and ferritin, and hepatic TG content. Attenuation of hepatic fibrosis by EPA-E was significantly correlated with hepatic ROS level, but not TG content.

CONCLUSIONS

EPA-E attenuates progression of hepatic fibrosis in developed steatohepatitis, and this effect is likely mediated by inhibition of ROS production. These actions may elicit the therapeutic effect of EPA-E against NASH.

Inducible nitric oxide distribution in the fatty liver of a mouse with high fat diet-induced obesity

Obesity is a condition of abnormal adipose tissue storage and recently it has been recognized as a major factor in metabolic syndrome. High-fat diet-induced obesity in the C57BL/6 mouse is an important animal model because of its similarities with human obesity. The aim of the present study was to estimate obesity, liver injury and steatohepatitis, and the distribution of inducible nitric oxide synthase (iNOS) in mice with high-fat diet induced obesity. Three-week-old male C57BL/6J mice were fed either a high-fat diet (D-60: 60 kcal% fat, or D-45: 45 kcal% fat) or a normal diet (D-10: 10 kcal% fat) for 15 weeks. Oral glucose tolerance tests and intraperitoneal glucose tolerance tests showed that the D-60 mice had severely impaired glucose tolerance. In serum chemistry values and histopathological lesions, the D-60 group showed severe steatohepatitis. A distinct positive signal for iNOS was detected by immunohistochemistry in the cytoplasm of hepatocytes around the central vein in the D-45 and D-60 groups. Serum insulin levels and insulin immunohistochemistry in the pancreas showed pancreatic injury and insulin resistance in the D-60 group. We observed the presence of more iNOS in the high-fat diet-induced obese mouse, which has characteristics of non-alcoholic steatohepatitis (NASH) and diabetes, and expect that these background pathological data will be useful in research on obesity, diabetes mellitus, and non-alcoholic fatty liver disease.