Steatohepatitis in obese individuals

A narrative review on the role of hesperidin on metabolic parameters, liver enzymes, and inflammatory markers in nonalcoholic fatty liver disease

Insulin resistance, oxidative stress, hyperlipidemia, and inflammation play main roles in the development of nonalcoholic fatty liver disease (NAFLD). Some studies have reported that hesperidin can reduce hyperglycemia and hyperlipidemia by inhibiting inflammatory pathways. In the current study, our purpose was to evaluate whether it can influence the primary parameters in NAFLD and improve the treatment effectiveness for future trials. Various studies have found that hesperidin involves multiple signaling pathways such as cell proliferation, lipid and glucose metabolism, insulin resistance, oxidative stress, and inflammation, which can potentially affect NAFLD development and prognosis. Recent findings indicate that hesperidin also regulates key enzymes and may affect the severity of liver fibrosis. Hesperidin inhibits reactive oxygen species production that potentially interferes with the activation of transcription factors like nuclear factor-κB. Appropriate adherence to hesperidin may be a promising approach to modulate inflammatory pathways, metabolic indices, hepatic steatosis, and liver injury.

Lycopene Improves Metabolic Disorders and Liver Injury Induced by a Hight-Fat Diet in Obese Rats

Epidemiological studies have shown that the consumption of a high-fat diet (HFD) is positively related to the development of obesity. Lycopene (LYC) can potentially combat HFD-induced obesity and metabolic disorders in rats. This study aimed to investigate the effect of LYC on metabolic syndrome and assess its anti-inflammatory and antioxidant effects on the liver and adipose tissue in rats fed an HFD. Thirty-six male Wistar albino rats were divided into three groups. Group Ι (the control group) was fed a normal diet, group ΙΙ (HFD) received an HFD for 16 weeks, and group ΙΙΙ (HFD + LYC) received an HFD for 12 weeks and then LYC (25 mg/kg b.wt) was administered for four weeks. Lipid peroxidation, antioxidants, lipid profile, liver function biomarkers, and inflammatory markers were determined. The results showed that long-term consumption of an HFD significantly increased weight gain, liver weight, and cholesterol and triglyceride levels. Rats on an HFD displayed higher levels of lipid peroxidation and inflammatory markers. Moreover, liver and white adipose tissue histopathological investigations showed that LYC treatment mended the damaged tissue. Overall, LYC supplementation successfully reversed HFD-induced changes and shifts through its antioxidant and anti-inflammatory activity. Therefore, LYC displayed a therapeutic potential to manage obesity and its associated pathologies.

GUT MICROBIOTA, PREBIOTICS, PROBIOTICS, AND SYNBIOTICS IN GASTROINTESTINAL AND LIVER DISEASES: PROCEEDINGS OF A JOINT MEETING OF THE BRAZILIAN SOCIETY OF HEPATOLOGY (SBH), BRAZILIAN NUCLEUS FOR THE STUDY OF HELICOBACTER PYLORI AND MICROBIOTA (NBEHPM), AND BRAZILIAN FEDERATION OF GASTROENTEROLOGY (FBG)

Over the last years, there is growing evidence that microorganisms are involved in the maintenance of our health and are related to various diseases, both intestinal and extraintestinal. Changes in the gut microbiota appears to be a key element in the pathogenesis of hepatic and gastrointestinal disorders, including non-alcoholic fatty liver disease, alcoholic liver disease, liver cirrhosis, inflammatory bowel disease, irritable bowel syndrome, and Clostridium difficile - associated diarrhea. In 2019, the Brazilian Society of Hepatology (SBH) in cooperation with the Brazilian Nucleus for the Study of Helicobacter Pylori and Microbiota (NBEHPM), and Brazilian Federation of Gastroenterology (FBG) sponsored a joint meeting on gut microbiota and the use of prebiotics, probiotics, and synbiotics in gastrointestinal and liver diseases. This paper summarizes the proceedings of the aforementioned meeting. It is intended to provide practical information about this topic, addressing the latest discoveries and indicating areas for future studies.

Characterizing Eckol as a Therapeutic Aid: A Systematic Review

The marine biosphere is a treasure trove of natural bioactive secondary metabolites and the richest source of structurally diverse and unique compounds, such as phlorotannins and halo-compounds, with high therapeutic potential. Eckol is a precursor compound representing the dibenzo-1,4-dioxin class of phlorotannins abundant in the Ecklonia species, which are marine brown algae having a ubiquitous distribution. In search of compounds having biological activity from macro algae during the past three decades, this particular compound has attracted massive attention for its multiple therapeutic properties and health benefits. Although several varieties of marine algae, seaweed, and phlorotannins have already been well scrutinized, eckol deserves a place of its own because of the therapeutic properties it possesses. The relevant information about this particular compound has not yet been collected in one place; therefore, this review focuses on its biological applications, including its potential health benefits and possible applications to restrain diseases leading to good health. The facts compiled in this review could contribute to novel insights into the functions of eckol and potentially enable its use in different uninvestigated fields.

Lysosomal acid lipase deficiency: a form of non-obese fatty liver disease (NOFLD)

INTRODUCTION

With the growing obesity epidemic, nonalcoholic fatty liver disease (NAFLD) is rapidly becoming one of the leading causes of liver disease worldwide. Although obesity is a main risk factor for the development of NAFLD, it can also develop in lean subjects and can be encountered in different clinical setting and in association with an array of genetic, metabolic, nutritional, infectious and drug-induced disorders. Areas covered: This article discusses causes of fatty liver in non-obese subjects focusing on Lysosomal acid lipase deficiency (LAL-D), a commonly overlooked disorder reviewing its prevalence, genetics, pathogenesis, clinical features, diagnosis and treatment. It will also review other causes of non-alcoholic fatty liver disease, which can be encountered in the absence of obesity and metabolic syndrome. Expert commentary: Although the prevalence of LAL-D has been estimated in the range of 1 in 40,000 and 1 in 300,000, this estimate is much more than the identified cases reported in the literature, which suggests that that the disease may be considerably under-diagnosed. There is a pressing need to educate clinicians about the disease, especially with the development of new promising therapeutic modalities.

Diabetic and dyslipidaemic morbidly obese exhibit more liver alterations compared with healthy morbidly obese

Background & aims

To study the origin of fat excess in the livers of morbidly obese (MO) individuals, we analysed lipids and lipases in both plasma and liver and genes involved in lipid transport, or related with, in that organ.

Methods

Thirty-two MO patients were grouped according to the absence (healthy: DM − DL −) or presence of comorbidities (dyslipidemic: DM − DL +; or dyslipidemic with type 2 diabetes: DM + DL +) before and one year after gastric bypass.

Results

The livers of healthy, DL and DM patients contained more lipids (9.8, 9.5 and 13.7 times, respectively) than those of control subjects. The genes implicated in liver lipid uptake, including HL, LPL, VLDLr, and FAT/CD36, showed increased expression compared with the controls. The expression of genes involved in lipid-related processes outside of the liver, such as apoB, PPARα and PGC1α, CYP7a1 and HMGCR, was reduced in these patients compared with the controls. PAI1 and TNFα gene expression in the diabetic livers was increased compared with the other obese groups and control group. Increased steatosis and fibrosis were also noted in the MO individuals.

Conclusions

Hepatic lipid parameters in MO patients change based on their comorbidities. The gene expression and lipid levels after bariatric surgery were less prominent in the diabetic patients. Lipid receptor overexpression could enable the liver to capture circulating lipids, thus favouring the steatosis typically observed in diabetic and dyslipidaemic MO individuals.

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The criteria used to define the “metabolically healthy” obese is not applicable to morbidly obese patients.

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Virtually no studies of how bariatric surgery affects depending on comorbidities and less how affect to the liver.

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Anthropometrics, fat, lipid profile and inflammation parameters are different depending of comorbidities, not only in plasma but also in liver.

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The extent of lipases and lipids in the liver biopsies could help not only the diagnosis but also to follow the course of recovery after surgery.

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The morbidly obese individuals with diabetes and dyslipidemia have more altered metabolic profiles than the other two groups.

Nutrition and Physical Activity in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide and it is associated with other medical conditions such as diabetes mellitus, metabolic syndrome, and obesity. The mechanisms of the underlying disease development and progression are not completely established and there is no consensus concerning the pharmacological treatment. In the gold standard treatment for NAFLD weight loss, dietary therapy, and physical activity are included. However, little scientific evidence is available on diet and/or physical activity and NAFLD specifically. Many dietary approaches such as Mediterranean and DASH diet are used for treatment of other cardiometabolic risk factors such as insulin resistance and type-2 diabetes mellitus (T2DM), but on the basis of its components their role in NAFLD has been discussed. In this review, the implications of current dietary and exercise approaches, including Brazilian and other guidelines, are discussed, with a focus on determining the optimal nonpharmacological treatment to prescribe for NAFLD.

In vitro assessment of drug-induced liver steatosis based on human dermal stem cell-derived hepatic cells

Steatosis, also known as fatty liver disease (FLD), is a disorder in which the lipid metabolism of the liver is disturbed, leading to the abnormal retention of lipids in hepatocytes. FLD can be induced by several drugs, and although it is mostly asymptomatic, it can lead to steatohepatitis, which is associated with liver inflammation and damage. Drug-induced liver injury is currently the major cause of postmarketing withdrawal of pharmaceuticals and discontinuation of the development of new chemical entities. Therefore, the potential induction of steatosis must be evaluated during preclinical drug development. However, robust human-relevant in vitro models are lacking. In the present study, we explore the applicability of hepatic cells (hSKP-HPCs) derived from postnatal skin precursors, a stem cell population residing in human dermis, to investigate the steatosis-inducing effects of sodium valproate (Na-VPA). Exposure of hSKP-HPC to sub-cytotoxic concentrations of this reference steatogenic compound showed an increased intracellular accumulation of lipid droplets, and the modulation of key factors involved in lipid metabolism. Using a toxicogenomics approach, we further compared Na-VPA-treated hSKP-HPC and Na-VPA-treated primary human hepatocytes to liver samples from patients suffering from mild and advanced steatosis. Our data show that in hSKP-HPC exposed to Na-VPA and liver samples of patients suffering from mild steatosis, but not in primary human hepatocytes, "liver steatosis" was efficiently identified as a toxicological response. These findings illustrate the potential of hSKP-HPC as a human-relevant in vitro model to identify hepatosteatotic effects of chemical compounds.

Obesity as a Disease

In recent years, obesity and related medical conditions have become leading public health concerns worldwide. Policy measures to combat or prevent obesity have been instated in a number of countries, with varying degrees of success. To stress the importance of obesity as a health issue, many professional health organizations, including the American Medical Association, have defined obesity itself as a disease. While this may be somewhat controversial, the high risk of comorbid conditions in obese individuals, the significant changes from healthy physiology that are present in the obese state, and the need for further public policies to address the public health threat and economic impact of obesity in the population are strong supporting arguments to label obesity as a disease.

Lipid lowering effects of iodothyronines: In vivo and in vitro studies on rat liver

Non-alcoholic fatty liver disease (NAFLD) is emerging as one of the most common liver diseases, leading to the increasing interest for new therapeutic approaches for its treatment. NAFLD primarily depends on a hypercaloric and/or unbalanced diet leading to overweight and obesity. The liver, in fact, plays a central role in lipid metabolism by importing free fatty acids from the blood and synthesizing, storing, oxidizing and exporting lipids. Furthermore, the liver is the target for the thyroid hormones, thyroxine (T₄) and 3,3’,5-triiodo-L-thyronine (T₃), that stimulate the basal metabolic rate and lead to body weight loss. In the last decade, other iodothyronines have been shown to possess biological relevance and play some thyromimetic activities; in particular, 3,5-diiodo-L-thyronine (T₂) gained large interest. The global effect of iodothyronines on liver lipid metabolism results from the balance between direct and indirect actions on the hepatocyte, leading to stimulation of lipid synthesis, oxidation and autophagy. In this review, the results so far obtained on both in vivo and in vitro models of hepatosteatosis are summarized in order to obtain an updated picture of the lipid-lowering effects of iodothyronines on mammalian liver.

Targeting Hepatic Glycerolipid Synthesis and Turnover to Treat Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) encompasses a spectrum of metabolic abnormalities ranging from simple hepatic steatosis (accumulation of neutral lipid) to development of steatotic lesions, steatohepatitis, and cirrhosis. NAFLD is extremely prevalent in obese individuals and with the epidemic of obesity; nonalcoholic steatohepatitis (NASH) has become the most common cause of liver disease in the developed world. NASH is rapidly emerging as a prominent cause of liver failure and transplantation. Moreover, hepatic steatosis is tightly linked to risk of developing insulin resistance, diabetes, and cardiovascular disease. Abnormalities in hepatic lipid metabolism are part and parcel of the development of NAFLD and human genetic studies and work conducted in experimentally tractable systems have identified a number of enzymes involved in fat synthesis and degradation that are linked to NAFLD susceptibility as well as progression to NASH. The goal of this review is to summarize the current state of our knowledge on these pathways and focus on how they contribute to etiology of NAFLD and related metabolic diseases.

Intestinal epithelial barrier function in liver cirrhosis: an extensive review of the literature

Recent evidence suggests that translocation of bacteria and bacterial products, such as endotoxin from the intestinal lumen into the systemic circulation is a contributing factor in the pathogenesis of chronic liver diseases and the development of complications in cirrhosis. In addition to alterations in the intestinal microbiota and immune system, dysfunction of the intestinal epithelial barrier may be an important factor facilitating bacterial translocation. This review aims to provide an overview of the current evidence of intestinal epithelial barrier dysfunction in human chronic liver diseases and cirrhosis, and to discuss possible contributing factors and mechanisms. Data suggest the presence of intestinal epithelial barrier dysfunction in patients with chronic liver diseases, but are more convincing in patients with cirrhosis, especially in those with complications. The barrier dysfunction can result from both direct and indirect effects of aetiological factors, such as alcohol and obesity, which can cause chronic liver diseases and ultimately cirrhosis. On the other hand characteristics of cirrhosis itself, including portal hypertension, alterations in the intestinal microbiota, inflammation and oxidative stress can affect barrier function of both small and large intestine and may contribute to the development of complications. In conclusion, there are indications for intestinal epithelial barrier dysfunction in patients with chronic liver diseases and especially in patients with cirrhosis, which can be caused by various factors affecting both the small and large intestine.

Serum circulating microRNA profiling for identification of potential type 2 diabetes and obesity biomarkers

Background and Aim

MicroRNAs are small non-coding RNAs that play important regulatory roles in a variety of biological processes, including complex metabolic processes, such as energy and lipid metabolism, which have been studied in the context of diabetes and obesity. Some particular microRNAs have recently been demonstrated to abundantly and stably exist in serum and to be potentially disease-specific. The aim of this profiling study was to characterize the expression of miRNA in serum samples of obese, nonobese diabetic and obese diabetic individuals to determine whether miRNA expression was deregulated in these serum samples and to identify whether any observed deregulation was specific to either obesity or diabetes or obesity with diabetes.

Patients and Methods

Thirteen patients with type 2 diabetes, 20 obese patients, 16 obese patients with type 2 diabetes and 20 healthy controls were selected for this study. MiRNA PCR panels were employed to screen serum levels of 739 miRNAs in pooled samples from these four groups. We compared the levels of circulating miRNAs between serum pools of each group. Individual validation of the twelve microRNAs selected as promising biomarkers was carried out using RT-qPCR.

Results

Three serum microRNAs, miR-138, miR-15b and miR-376a, were found to have potential as predictive biomarkers in obesity. Use of miR-138 or miR-376a provides a powerful predictive tool for distinguishing obese patients from normal healthy controls, diabetic patients, and obese diabetic patients. In addition, the combination of miR-503 and miR-138 can distinguish diabetic from obese diabetic patients.

Conclusion

This study is the first to show a panel of serum miRNAs for obesity, and compare them with miRNAs identified in serum for diabetes and obesity with diabetes. Our results support the use of some miRNAs extracted from serum samples as potential predictive tools for obesity and type 2 diabetes.

Prospective histopathologic evaluation of lifestyle modification in nonalcoholic fatty liver disease: a randomized trial

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) is now recognized as part of the metabolic syndrome, and is specifically related to obesity and insulin resistance. Lifestyle modification is advocated for the treatment of NAFLD, but few studies have evaluated its impact on liver histology. The purpose of this study was to investigate which, if any, specific diet and exercise recommendations are associated with histopathologic changes.

METHODS

A total of 56 participants were randomly assigned to 1 of 4 lifestyle modification subgroups for 6 months: standard care, low-fat diet and moderate exercise, moderate-fat/low-processed-carbohydrate diet and moderate exercise, or moderate exercise only. All subjects had biopsy-proven NAFLD, to include nonalcoholic steatohepatitis (NASH), and received a repeat 6-month biopsy to detect histopathologic changes. Other measures included blood assay of liver enzymes (aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase), fasting glucose, serum insulin, lipid panel, body weight, dietary intake, fat mass, and fitness level.

RESULTS

Among the 41 participants who completed the study (88% with NASH), a significant change was found in pre- to post-NAFLD activity score in the group as a whole (p < 0.001) with no difference detected between subgroups (p = 0.31). Our results confirm that lifestyle modification is effective in improving NAFLD and NASH.

CONCLUSIONS

Regardless of intervention group, lifestyle modification improved liver histology, as verified by repeat biopsy, after a 6-month intervention. This study reinforces the importance of lifestyle modification as the primary treatment strategy for patients with NAFLD.

Relationship between visceral adipose tissue and adiponectin, inflammatory markers and thyroid hormones in obese males with hepatosteatosis and insulin resistance

BACKGROUND AND AIMS

In our detailed analysis of the recent academic publications, we have not found sufficient evidence regarding the changes of metabolism that occur in cases of insulin resistance (IR) and nonalcoholic fatty liver disease (NAFLD). We aimed to investigate the changes in various biomarkers of obese patients by taking into consideration the IR and NAFLD, which occur increasingly together.

METHODS

Obese male patients included in the study (n = 315) were divided into three groups. Group I was determined as mild pathology (n = 129; HOMA-IR ≥2.5 and grade 0 or HOMA-IR <2.5 and grade 1-2 hepatosteatosis), group II as moderate pathology (n = 145; HOMA-IR ≥2.5 and grade 1-2 or HOMA-IR <4 and grade 3 hepatosteatosis) and group III as severe pathology (n = 41; HOMA-IR ≥4 and grade 3 hepatosteatosis). Waist circumference (WC), percent body fat (%BF), visceral adipose tissue (VAT), subcutaneous abdominal fat tissue (SCAT), thyroid volume (Tvol), thyroid hormones, insulin, adiponectin, fibrinogen and ultrasensitive C-reactive protein (us-CRP) were measured in all patients.

RESULTS

A negative correlation between adiponectin and HOMA-IR was found (r = -0.4226; p <0.001). In addition, there were significant differences among all three groups with respect to VAT (p <0.01). Moreover total-triiodo-L-thyronine (TT3) and free-triiodo-L-thyronine (fT3) levels were observed first to decrease in group II compared to group I and then to increase in group III (p <0.001). Fibrinogen and us-CRP levels in group III were significantly higher (p <0.001).

CONCLUSIONS

TT3 and fT3 levels as well as adiponectin, fibrinogen and us-CRP levels may be affected by the relationship between IR and NAFLD in obese patients. Moreover, increased VAT is a more important risk factor than WC, %BF and BMI, with respect to IR and NAFLD.

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

GOALS/BACKGROUND

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

STUDY

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

RESULTS

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

CONCLUSIONS

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

Upregulation of miR-15b in NAFLD models and in the serum of patients with fatty liver disease

AIM

In the present study, we examined the expression and function of miR-15b in a rat model of non-alcoholic fatty liver disease (NAFLD), and we determined whether the presence of miR-15b in serum can be used as a biomarker for this disease.

METHODS

We measured the expression of miR-15b in both the high-fat-induced non-alcoholic fatty liver disease (NAFLD) SD rat model and in the palmitate-induced NAFLD L02 cell model. Following transfection of miR-15b into QSG7701 cells, cell proliferation, glucose consumption and intracellular triglyceride levels were measured. We also measured the levels of miR-15b in the serum of fatty liver disease patients using real-time PCR.

RESULTS

We found that miR-15b was upregulated in the livers of NAFLD SD rats as well as in NAFLD L02 cells. Increased miR-15b levels could cause decreased cell proliferation and glucose consumption as well as induce the storage of intracellular triglyceride in QSG7701 cells. The expression of miR-15b was also significantly elevated in the serum of fatty liver disease patients compared with healthy subjects.

CONCLUSIONS

Increased miR-15b expression in NAFLD models may lead to decreased cell proliferation and glucose consumption while inducing the storage of intracellular triglyceride, which are all hazards of NAFLD. Therefore, increased serum miR-15b level is a potentially biomarker for the diagnosis of fatty liver disease.

Polyphenol-Rich Fraction of Brown Alga Ecklonia cava Collected from Gijang, Korea, Reduces Obesity and Glucose Levels in High-Fat Diet-Induced Obese Mice

Ecklonia cava (E. cava) is a brown alga that has beneficial effects in models of type 1 and type 2 diabetes. However, the effects of E. cava extracts on diet-induced obesity and type 2 diabetes have not been specifically examined. We investigated the effects of E. cava on body weight, fat content, and hyperglycemia in high-fat diet- (HFD) induced obese mice and sought the mechanisms involved. C57BL/6 male mice were fed a HFD (60% fat) diet or normal chow. After 3 weeks, the HFD diet group was given extracts (200 mg/kg) of E. cava harvested from Jeju (CA) or Gijang (G-CA), Korea or PBS by oral intubation for 8 weeks. Body weights were measured weekly. Blood glucose and glucose tolerance were measured at 7 weeks, and fat pad content and mRNA expression of adipogenic genes and inflammatory cytokines were measured after 8 weeks of treatment. G-CA was effective in reducing body weight gain, body fat, and hyperglycemia and improving glucose tolerance as compared with PBS-HFD mice. The mRNA expression of adipogenic genes was increased, and mRNA expression of inflammatory cytokines and macrophage marker gene was decreased in G-CA-treated obese mice. We suggest that G-CA reduces obesity and glucose levels by anti-inflammatory actions and improvement of lipid metabolism.

Analysis of vanin-1 upregulation and lipid accumulation in hepatocytes in response to a high-fat diet and free fatty acids

High-fat diet is one of the causes of nonalcoholic fatty liver disease. We have previously demonstrated that high-fat diet induces upregulation of adipose differentiation-related protein mRNA expression accompanied by lipid droplet formation in mouse liver. Vanin-1 is a ubiquitous epithelial ectoenzyme that has pantetheinase activity and produces cysteamine, a potent endogenous antioxidant. In the present study, we analyzed the expression of hepatic vanin-1 mRNA following the administration of a high-fat diet in mice as well as free fatty acids in hepatocyte cultures and speculated its possible mechanism. Vanin-1 mRNA levels in the livers of mice were upregulated within a day of the high-fat diet, even before the expression of adipose differentiation-related protein mRNA and lipid accumulation. An in vitro analysis using HuH-7 cells revealed a significant upregulation of vanin-1 mRNA by as low as 0.01 mM oleic acid; however, lipid accumulation in hepatocytes was not affected at this concentration. Furthermore, vanin-1 mRNA was differentially upregulated by various free fatty acids irrespective of the grade of lipid accumulation. These findings indicate that the upregulation of vanin-1 precedes lipid accumulation and is differentially mediated by various types of free fatty acids in the model, presenting vanin-1 as a novel player in the pathogenesis of nonalcoholic fatty liver disease.

Nutrigenomics of hepatic steatosis in a feline model: effect of monosodium glutamate, fructose, and Trans-fat feeding

Nonalcoholic fatty liver disease begins with a relatively benign hepatic steatosis, often associated with increased adiposity, but may progress to a more severe nonalcoholic steatohepatitis with inflammation. A subset of these patients develops progressive fibrosis and ultimately cirrhosis. Various dietary components have been shown to contribute to the development of liver disease, including fat, sugars, and neonatal treatment with high doses of monosodium glutamate (MSG). However, rodent models of progressive disease have been disappointing, and alternative animal models of diet-induced liver disease would be desirable, particularly if they contribute to our knowledge of changes in gene expression as a result of dietary manipulation. The domestic cat has previously been shown to be an appropriate model for examining metabolic changes-associated human diseases such as diabetes. Our aim was therefore to compare changes in hepatic gene expression induced by dietary MSG, with that of a diet containing Trans-fat and high fructose corn syrup (HFCS), using a feline model. MSG treatment increased adiposity and promoted hepatic steatosis compared to control (P < 0.05). Exposure to Trans-fat and HFCS promoted hepatic fibrosis and markers of liver dysfunction. Affymetrix microarray analysis of hepatic gene expression showed that dietary MSG promoted the expression of genes involved in cholesterol and steroid metabolism. Conversely, Trans-fat and HFCS feeding promoted the expression of genes involved in lipolysis, glycolysis, liver damage/regeneration, and fibrosis. Our feline model examining gene-diet interactions (nutrigenomics) demonstrates how dietary MSG, Trans-fat, and HFCS may contribute to the development of hepatic steatosis.

High fat diet induced downregulation of microRNA-467b increased lipoprotein lipase in hepatic steatosis

Non-alcoholic fatty liver disease (NAFLD) is characterized by hepatic fat accumulation and is presently the most common chronic liver disease. However, the mechanisms underlying the development of steatosis remain unclear. MicroRNAs (miRNAs) are small non-coding RNAs that modulate a variety of biological functions. We have investigated the role of miRNA in the development of steatosis. We found that miR-467b expression is significantly downregulated in liver tissues of high-fat diet fed mice and in steatosis-induced hepatocytes. The downregulation of miR-467b resulted in the upregulation of hepatic lipoprotein lipase (LPL), the direct target of miR-467b. Moreover, the interaction between miR-467b and LPL was associated with insulin resistance, a major cause of NAFLD. These results suggest that downregulation of miR-467b is involved in the development of hepatic steatosis by modulating the expression of its target, LPL.

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.

Steatosis and steatohepatitis in postmortem material from Northwestern Greece

AIM: To determine the prevalence of steatosis and steatohepatitis in a series of autopsies in Northwestern Greece.

METHODS: Liver biopsy material from a total of 600 autopsies performed over a period of 2 years (2006-2008) to define the cause of death was subjected to histological examination. Patient demographic data were also collected. Tissue sections were stained with different dyes for the evaluation of liver architecture, degree of fibrosis and other pathological conditions when necessary.

RESULTS: Satisfactory tissue samples for histological evaluation were available in 498 cases (341 male, 157 female) with a mean age of 64.51 ± 17.78 years. In total, 144 (28.9%) had normal liver histology, 156 (31.3%) had evidence of steatosis, and 198 (39.8%) had typical histological findings of steatohepatitis. The most common causes of death were ischemic heart disease with or without myocardial infarction (43.4%), and traffic accidents (13.4%).

CONCLUSION: A high prevalence of steatosis and steatohepatitis was detected in postmortem biopsies from Northwestern Greece. Since both diseases can have serious clinical consequences, they should be considered as an important threat to the health of the general population in Greece.

Ensemble modeling of hepatic fatty acid metabolism with a synthetic glyoxylate shunt

The liver plays a central role in maintaining whole body metabolic and energy homeostasis by consuming and producing glucose and fatty acids. Glucose and fatty acids compete for hepatic substrate oxidation with regulation ensuring glucose is oxidized preferentially. Increasing fatty acid oxidation is expected to decrease lipid storage in the liver and avoid lipid-induced insulin-resistance. To increase hepatic lipid oxidation in the presence of glucose, we previously engineered a synthetic glyoxylate shunt into human hepatocyte cultures and a mouse model and showed that this synthetic pathway increases free fatty acid beta-oxidation and confers resistance to diet-induced obesity in the mouse model. Here we used ensemble modeling to decipher the effects of perturbations to the hepatic metabolic network on fatty acid oxidation and glucose uptake. Despite sampling of kinetic parameters using the most fundamental elementary reaction models, the models based on current metabolic regulation did not readily describe the phenotype generated by glyoxylate shunt expression. Although not conclusive, this initial negative result prompted us to probe unknown regulations, and malate was identified as inhibitor of hexokinase 2 expression either through direct or indirect actions. This regulation allows the explanation of observed phenotypes (increased fatty acid degradation and decreased glucose consumption). Moreover, the result is a function of pyruvate-carboxylase, mitochondrial pyruvate transporter, citrate transporter protein, and citrate synthase activities. Some subsets of these flux ratios predict increases in fatty acid and decreases in glucose uptake after glyoxylate expression, whereas others predict no change. Altogether, this work defines the possible biochemical space where the synthetic shunt will produce the desired phenotype and demonstrates the efficacy of ensemble modeling for synthetic pathway design.

Procedure and outcomes of Roux-en-Y gastric bypass

Bariatric surgery is an effective intervention for weight loss in the morbidly obese patient and can result in resolution of associated comorbidities. However, it is a complex area of practice and care, as these patients suffer a series of comorbidities that can compromise outcomes after surgery. Nurses must be aware of these comorbidities and anticipate the required interventions to ensure timely and effective treatment, and to minimize potential problems. This article reviews the technical procedures of the laparoscopic Roux-en-Y gastric bypass (LRYGBP)--which is considered the gold standard in bariatric surgery--and outlines its complications and outcomes. Other forms of bariatric surgery are briefly discussed in comparison to the LRYGBP. With knowledge in this area, nurses are in a ideal position to educate and prepare patients for life after surgery, and to diminish their anxiety during adaptation to this new phase of life.

The relationship of omental and subcutaneous adipocyte size to metabolic disease in severe obesity

Objective

Several studies have reported the existence of a subgroup of obese individuals with normal metabolic profiles. It remains unclear what factors are responsible for this phenomenon. We proposed that adipocyte size might be a key factor in the protection of metabolically healthy obese (MHO) individuals from the adverse effects of obesity.

Subjects

Thirty-five patients undergoing bariatric surgery were classified as MHO (n = 15) or metabolically unhealthy obese (MUO, n = 20) according to cut-off points adapted from the International Diabetes Federation definition of the metabolic syndrome. Median body mass index (BMI) was 48 (range 40–71).

Results

There was a moderate correlation between omental adipocyte size and subcutaneous adipocyte size (r = 0.59, p<0.05). The MHO group had significantly lower mean omental adipocyte size (80.9±10.9 µm) when compared with metabolically unhealthy patients (100.0±7.6 µm, p<0.0001). Mean subcutaneous adipocyte size was similar between the two groups (104.1±8.5 µm versus 107.9±7.1 µm). Omental, but not subcutaneous adipocyte size, correlated with the degree of insulin resistance as measured by HOMA-IR (r = 0.73, p<0.0005), as well as other metabolic parameters including triglyceride/HDL-cholesterol ratio and HbA1c. Twenty-eight patients consented to liver biopsy. Of these, 46% had steatohepatitis and fibrosis. Fifty percent (including all the MHO patients) had steatosis only. Both omental and subcutaneous adipocyte size were significantly associated with the degree of steatosis (r = 0.66, p<0.0001 and r = 0.63, p<0.005 respectively). However, only omental adipocyte size was an independent predictor of the presence or absence of fibrosis.

Conclusion

Metabolically healthy individuals are a distinct subgroup of the severely obese. Both subcutaneous and omental adipocyte size correlated positively with the degree of fatty liver, but only omental adipocyte size was related to metabolic health, and possibly progression from hepatic steatosis to fibrosis.

Hepatic artery resistance in children with obesity and fatty liver

OBJECTIVE

The present study assessed whether there is a correlation between hepatic artery resistive index (HARI) and increase of body mass index and hepatosteatosis grading in children with non-alcoholic fatty liver disease (NAFLD) reflecting hemodynamic effects of hepatosteatosis.

METHODS

Thirty three healthy children [body mass index(BMI): mean+/- standart deviation(SD), min-max: 20.1+/-1.14(18.5-23.7), 33 overweight [BMI:25.1+/-2.2 (18.5-23.7)] and 66 obese [BMI:31.1+/-2(25.6-40)] adolescents were enrolled into the study. To search the relation of HARI with fatty liver degree, study subjects subdivided into groups according to their degree of fatty liver at ultrasonography(US).

RESULTS

Increase of HARI was correlated with increase in BMI (p<0.0001, r=0.533). Increase of HARI was well correlated with increase in degree of fatty liver (p<0.0001, r=0.630).

CONCLUSION

The present study results suggest that there are positive correlations of HARI with BMI and hepatosteatosis grade in obese children with NAFLD. HARI may be a candidate parameter to determine early alarming hemodynamic changes in hepatic tissue of obese children with fatty liver before development of severe stages NAFLD.

Inflammatory mediators of hepatic steatosis

Nonalcoholic fatty liver disease (NAFLD) is rapidly becoming a world-wide public health problem. NAFLD represents a spectrum of disease ranging from "simple steatosis", which is considered relatively benign, to nonalcoholic steatohepatitis and to NAFLD-associated cirrhosis and end-stage liver disease. The etiology of NAFLD and its progression is complex and remains incompletely understood. The progression of the disease involves many factors. Apart from the two hits, the accumulation of TG and the development of fibrosis and necroinflammatory processes, exit numerous molecules associated with these two hits. Among them we can highlight the pro-inflammatory molecules and adiponectins. This review focuses on the growing evidence from both experimental and human studies suggesting a central role of cytokines in the pathogenesis of NAFLD. We review the role of cytokines as key regulators of insulin sensitivity and hepatic lipid overloading, liver injury and inflammation, and fibrosis with an emphasis on potential therapeutic implications.

Hepatic expression of cell death-inducing DFFA-like effector C in obese subjects is reduced by marked weight loss

The hepatic expression of the cell death-inducing DNA fragmentation factor A-like effector family (CIDEA, CIDEB, and CIDEC) genes is markedly upregulated in mouse models of obesity. We evaluated the expression of CIDE genes in liver of obese human subjects undergoing gastric bypass surgery (GBS), at the time of surgery and again 1 year later when subjects had lost 37.6 +/- 1.4% of their initial body weight. At the time of GBS, the expression of CIDEA (r(2) = 0.20, P = 0.04) and CIDEC (r(2) = 0.32, P = 0.01) was strongly correlated with BMI, whereas CIDEB was not (r(2) = 0.01, P = 0.81). One year after surgery, CIDEC expression had declined over 60% (P = 0.02), whereas CIDEA expression did not change (P = 0.20). These data demonstrate that, consistent with previous studies conducted in rodents, hepatic expression of CIDEA and CIDEC, but not CIDEB, is increased in obese humans. Moreover, the hepatic expression of CIDEC is downregulated by marked weight loss.

A subset of dysregulated metabolic and survival genes is associated with severity of hepatic steatosis in obese Zucker rats

We aimed to characterize the primary abnormalities associated with fat accumulation and vulnerability to hepatocellular injury of obesity-related fatty liver. We performed functional analyses and comparative transcriptomics of isolated primary hepatocytes from livers of obese insulin-resistant Zucker rats (comprising mild to severe hepatic steatosis) and age-matched lean littermates, searching for novel genes linked to chronic hepatic steatosis. Of the tested genome, 1.6% was identified as steatosis linked. Overexpressed genes were mainly dedicated to primary metabolism (100%), signaling, and defense/acute phase (approximately 70%); detoxification, steroid, and sulfur metabolism (approximately 65%) as well as cell growth/proliferation and protein synthesis/transformation (approximately 70%) genes were downregulated. The overexpression of key genes involved in de novo lipogenesis, fatty acid and glycerolipid import and synthesis, as well as acetyl-CoA and cofactor provision was paralleled by enhanced hepatic lipogenesis and production of large triacylglycerol-rich VLDL. Greatest changes in gene expression were seen in those encoding the lipogenic malic enzyme (up to 7-fold increased) and cell-to-cell interacting cadherin 17 (up to 8-fold decreased). Among validated genes, fatty acid synthase, stearoyl-CoA desaturase 1, fatty acid translocase/Cd36, malic enzyme, cholesterol-7 alpha hydroxylase, cadherin 17, and peroxisome proliferator-activated receptor alpha significantly correlated with severity of hepatic steatosis. In conclusion, dysregulated expression of metabolic and survival genes accompany hepatic steatosis in obese insulin-resistant rats and may render steatotic hepatocytes more vulnerable to cell injury in progressive nonalcoholic fatty liver disease.

Resistance to diet-induced obesity in mice with synthetic glyoxylate shunt

Given the success in engineering synthetic phenotypes in microbes and mammalian cells, constructing non-native pathways in mammals has become increasingly attractive for understanding and identifying potential targets for treating metabolic disorders. Here, we introduced the glyoxylate shunt into mouse liver to investigate mammalian fatty acid metabolism. Mice expressing the shunt showed resistance to diet-induced obesity on a high-fat diet despite similar food consumption. This was accompanied by a decrease in total fat mass, circulating leptin levels, plasma triglyceride concentration, and a signaling metabolite in liver, malonyl-CoA, that inhibits fatty acid degradation. Contrary to plants and bacteria, in which the glyoxylate shunt prevents the complete oxidation of fatty acids, this pathway when introduced in mice increases fatty acid oxidation such that resistance to diet-induced obesity develops. This work suggests that using non-native pathways in higher organisms to explore and modulate metabolism may be a useful approach.

Lipoprotein lipase expression in livers of morbidly obese patients could be responsible for liver steatosis

BACKGROUND

Most patients with morbid obesity develop non-alcoholic fatty liver disease (NAFLD). The origins of lipid deposition in the liver and the effects of bariatric surgery in the obese with NAFLD are controversial.

METHODS

We analyzed lipids and lipoprotein lipase (LPL) in both plasma and liver biopsies performed before and 12-18 months after Roux-en-Y gastric bypass surgery in 26 patients.

RESULTS

In the livers of morbidly obese patients, the levels of LPL messenger RNA (mRNA) were higher (4.5-fold) before surgery than afterwards than control livers. In these patients, LPL activity was also significantly higher (91 +/- 7 mU/g) than in controls (51 +/- 3 mU/g, p = 0.0026) and correlated with the severity of the liver damage. All hepatic lipids were significantly increased in obese patients; however, after bariatric surgery, these lipids, with the exception of NEFA, tended to recover to normal levels.

CONCLUSIONS

The liver of obese patients presented higher LPL activity than controls, and unlike the controls, this enzyme could be synthesized in the liver because it also present LPL mRNA. The presence of the LPL activity could enable the liver to capture circulating triacylglycerides, thus favoring the typical steatosis observed in these patients.

[Nonalcoholic steatohepatitis: pathogenesis and treatment]

Nonalcoholic fatty liver disease (NAFLD) is characterized by a wide spectrum of liver damage spanning steatosis, nonalcoholic steatohepatitis (NASH), cryptogenic liver cirrhosis, and even to hepatocellular carcinoma. Investigations in the last few years have focused on NASH, a relatively aggressive form of liver disease, due largely to the explosion of information provided by clinical and basic science studies related to the widespread presence of risk factors, such as obesity, type II diabetes mellitus, and dyslipidemia. This is especially important given that obesity and type II diabetes mellitus have recently reached epidemic proportions in Korea. The pathogenesis of NASH is multifactorial, with insulin resistance and increased fatty acid possibly being important factors in the accumulation of hepatocellular fat, and oxidant stress, lipid peroxidation, mitochondrial dysfunction, and dysregulation of variable cytokines possibly being important causes of hepatocellular injury in steatotic liver. Because not all steatotic livers progress to NASH, some other environmental factors or a combination of genetic factors are thought to be required for progression to NASH and fibrosis. Lifestyle modifications continue to be the cornerstone therapy in NAFLD, but some insulin-sensitizing drugs might be more effective in treating NASH. Many pilot trials for antioxidants and lipid-lowering and hepatic protective agents have yielded promising initial results in improving liver enzymes or features of liver histology. However, the efficacy of these agents remains questionable. Despite recent gains in understanding NASH, several issues related to its natural history, pathogenesis, and treatment remain unresolved.

A decision analysis study of the value of a liver biopsy in nonalcoholic steatohepatitis

OBJECTIVES

Nonalcoholic fatty liver disease (NAFLD) is an increasingly prevalent clinical syndrome reflecting a mixture of pathological liver histology with the potential to progress to cryptogenic cirrhosis. Liver biopsy (LB) is the only way to determine the severity of disease. However, LB is invasive, has complications and financial costs. The aim of this study is to determine the benefits of early LB for diagnosis and early treatment.

METHODS

A decision tree model tracked the potential outcomes of NAFLD between an LB-directed approach vs. no initial LB. Each specific biopsy category determined subsequent care actions. The baseline probabilities were determined by literature review and expert opinion.

RESULTS

An initial LB strategy was projected to have a lower mortality compared with the no initial LB group and fewer transplant eligible patients after 5 years. If the prevalence of NAFLD is increased, the mortality increases in both the study groups. With improved efficacy of medical and/or surgical intervention, the mortality rate was decreased.

CONCLUSION

This decision tree model provides a context for balancing the risk and benefit of LB in NAFLD. With early biopsy, and early intervention, the relative return of preventing advanced liver disease per LB was high.

Fatty liver disease in severe obese patients: Diagnostic value of abdominal ultrasound

AIM: To evaluate the sensitivity and specificity of abdominal ultrasound (US) for the diagnosis of hepatic steatosis in severe obese subjects and its relation to histological grade of steatosis.

METHODS: A consecutive series of obese patients, who underwent bariatric surgery from October 2004 to May 2005, was selected. Ultrasonography was performed in all patients as part of routine preoperative time and an intraoperative wedge biopsy was obtained at the beginning of the bariatric surgery. The US and histological findings of steatosis were compared, considering histology as the gold standard.

RESULTS: The study included 105 patients. The mean age was 37.2 ± 10.6 years and 75.2% were female. The histological prevalence of steatosis was 89.5%. The sensitivity and specificity of US in the diagnosis of hepatic steatosis were, respectively, 64.9% (95% CI: 54.9-74.3) and 90.9% (95% CI: 57.1-99.5). The positive predictive value and negative predictive value were, respectively, 98.4% (95% CI: 90.2-99.9) and 23.3% (95% CI: 12.3-39.0). The presence of steatosis on US was associated to advanced grades of steatosis on histology (P = 0.016).

CONCLUSION: Preoperative abdominal US in our series has not shown to be an accurate method for the diagnosis of hepatic steatosis in severe obese patients. Until another non-invasive method demonstrates better sensitivity and specificity values, histological evaluation may be recommended to these patients undergoing bariatric surgery.

Nonalcoholic fatty liver disease in severely obese subjects

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) has been consistently associated with obesity and insulin resistance. Nonalcoholic steatohepatitis (NASH) is a histological entity within NAFLD that can progress to cirrhosis. The exact prevalence of NASH in severe obesity is unknown. It is unclear whether differences in insulin sensitivity exist among subjects with NASH and simple fatty liver.

OBJECTIVE

To evaluate the prevalence and correlates of NASH and liver fibrosis in a racially diverse cohort of severely obese subjects.

DESIGN

Ninety-seven subjects were enrolled. Liver biopsies, indirect markers of insulin resistance, metabolic parameters, and liver function tests were obtained.

RESULTS

Thirty-six percent of subjects had NASH and 25% had fibrosis. No cirrhosis was diagnosed on histology. Markers of hyperglycemia, insulin resistance, and the metabolic syndrome but not body mass index were associated with the presence of NASH and fibrosis. Elevated transaminase levels correlated strongly with NASH and fibrosis but 46% subjects with NASH had normal transaminases. Subjects with NASH had more severe insulin resistance when compared to those with simple fatty liver. A signal detection model incorporating AST and the presence of diabetes predicted the presence of NASH while another incorporating ALT and HbA1C predicted the presence of fibrosis.

CONCLUSIONS

NAFLD is associated with the metabolic syndrome rather than excess adipose tissue in severe obesity. Insulin resistance is higher in subjects with NASH versus those with simple fatty liver. Statistical models incorporating markers of liver injury and hyperglycemia may be useful in predicting the presence of liver pathology in this population.

Race and comorbid factors predict nonalcoholic fatty liver disease histopathology in severely obese patients

PURPOSE

Nonalcoholic fatty liver disease (NAFLD) is a common and potentially serious form of chronic liver disease. Although NAFLD is known to be associated with obesity and some comorbid conditions, less is known about the severity of NAFLD among different racial groups.

METHODS

We prospectively studied 237 consecutive morbidly obese patients presenting for bariatric surgery. All patients underwent intraoperative liver biopsy and chart review. After excluding subjects who reported alcohol use (n = 37) or who had missing biopsy data (n = 11), 189 patients were available for analysis. Clinical and laboratory associations with each of the histological components of NAFLD were assessed using multiple logistic regression analysis.

RESULTS

The mean age was 43.1 years, 84% were female, and 13% were African American. It was found that 88% had steatosis, including 35% with moderate to severe steatosis (> 33% of hepatocytes involved). Of these patients, 67% had inflammation, 46% had fibrosis, and 45% met Brunt's criteria for NASH. Compared with Caucasians and after adjustment, African Americans had significantly lower odds of severe hepatic pathology, with adjusted odds ratios of 0.1 (P = .02) for the presence of moderate or severe steatosis, 0.2 for inflammation (P = .006), 0.3 for fibrosis (P = .05), and 0.2 for NASH (P = .02). In addition, participants with one or more features of the metabolic syndrome (ie, diabetes, hypertension, or dyslipidemia) or elevated aminotransferase levels had significantly higher odds of severe hepatic histopathology.

CONCLUSION

Among obese patients presenting for bariatric surgery, NAFLD is more common in Caucasians, patients with features of the metabolic syndrome, and those with elevated aminotransferase levels.

Lipin 1 is an inducible amplifier of the hepatic PGC-1alpha/PPARalpha regulatory pathway

Perturbations in hepatic lipid homeostasis are linked to the development of obesity-related steatohepatitis. Mutations in the gene encoding lipin 1 cause hepatic steatosis in fld mice, a genetic model of lipodystrophy. However, the molecular function of lipin 1 is unclear. Herein, we demonstrate that the expression of lipin 1 is induced by peroxisome proliferator-activated receptor gamma (PPARgamma) coactivator 1alpha (PGC-1alpha), a transcriptional coactivator controlling several key hepatic metabolic pathways. Gain-of-function and loss-of-function strategies demonstrated that lipin selectively activates a subset of PGC-1alpha target pathways, including fatty acid oxidation and mitochondrial oxidative phosphorylation, while suppressing the lipogenic program and lowering circulating lipid levels. Lipin activates mitochondrial fatty acid oxidative metabolism by inducing expression of the nuclear receptor PPARalpha, a known PGC-1alpha target, and via direct physical interactions with PPARalpha and PGC-1alpha. These results identify lipin 1 as a selective physiological amplifier of the PGC-1alpha/PPARalpha-mediated control of hepatic lipid metabolism.

Breath biomarkers and non-alcoholic fatty liver disease: preliminary observations

Breath biomarkers have the potential to offer information that is similar to conventional clinical tests or they are entirely unique. Preliminary data support the use of breath biomarkers in the study of liver disease, in particular non-alcoholic fatty liver disease (NAFLD). It was evaluated whether breath ethanol, ethane, sulfur compounds and acetone would be associated with hepatic histopathology amongst morbidly obese patients presenting for bariatric surgery. Breath samples were collected during a preoperative visit and compared with liver biopsies obtained during the surgery. A Student's two-tailed t-test was used to compare differences between the two groups. Linear regression was used to analyse associations between the concentrations of breath molecules and independent predictor variables. It was found that breath ethanol, ethane and acetone can be useful biomarkers in patients with NAFLD. In particular, breath ethanol can be associated with hepatic steatosis, and breath acetone can be associated with non-alcoholic steatohepatitis.

Association of cardiorespiratory fitness, body mass index, and waist circumference to nonalcoholic fatty liver disease

BACKGROUND & AIMS

There is a need for more work examining the potential of physical activity and/or weight control as a preventive and/or therapeutic option in the treatment of fatty liver diseases. The purpose of this study was to examine the association between cardiorespiratory fitness, body mass index (BMI), and waist circumference with markers of nonalcoholic fatty liver disease (NAFLD).

METHODS

Participants consisted of 218 apparently healthy nonsmoking, nonalcoholic men aged 33-73 years. Cardiorespiratory fitness was assessed by a maximal treadmill test. Liver and spleen density were measured using a computed tomography scan. We defined the presence of NAFLD as the following 3 conditions being met: (1) liver to spleen density of 1.0 or less, (2) serum alanine transaminase level greater than 30 U/L, and (3) serum aspartate transaminase/alanine transaminase level less than 1.0.

RESULTS

Twenty-four (11%) of the participants met the NAFLD definition. There was an inverse association between fitness categories, and a positive association for BMI categories (and waist circumference categories) with the prevalence of NAFLD (P for trend <.001 for all). Fitness and BMI were independent of each other in their associations with the prevalence of NAFLD. The addition of waist circumference to the regression model attenuated the association with prevalence of NAFLD for both fitness (P value changed from <.0001 to .06) and BMI (P value changed from <.001 to .22).

CONCLUSIONS

Fitness (inversely) and BMI (directly) were associated with the prevalence of NAFLD. However, these associations were attenuated when abdominal obesity was included in the statistical model.

How different is the dietary pattern in non-alcoholic steatohepatitis patients?

BACKGROUND/AIMS

This study aimed at evaluating whether patients with non-alcoholic steatohepatitis (NASH) had a specific dietary pattern and how it compared with data representative from the same geographical region individuals.

SUBJECTS AND METHODS

Clinical, biochemical and anthropometrics: weight, height, body mass index (BMI) and waist circumference were collected in 45 NASH patients. Diet history was assessed using a validated semi-quantitative food frequency questionnaire, analysed with the Food Processor Plus, and was compared, after adjustment for BMI, with data from a sample of 856 free-living individuals, frequency matched for sex and age.

RESULTS

Patients' mean age was 49.6+/-10.6 years, 26 F: 19 M, BMI: 31.2+/-5.0 kg/m2. Comparison of their diet history with control data (C) revealed that carbohydrate consumption was lower in patients (P): P-243.6+/-5.7 g vs. C-261.5+/-1.6 g, P<0.05, and most patients had very low fibre intake. Conversely, total fat consumption was higher in patients: P-79.7+/-1.7 g vs. 73.0+/-0.4, P<0.01. A significantly higher intake of n-6 fatty acids (P=0.003) and n-6/n-3 ratio was found in patients, P<0.001.

CONCLUSIONS

Our results suggest that the quality and combination of carbohydrates and fat intake may be more relevant than their isolated amount; an increased fat intake with an excessive amount of n-6 fatty acids can be implicated in promoting necro-inflammation, and provides further grounds for individualized dietary therapy.

Serum adiponectin, resistin levels and non-alcoholic fatty liver disease in obese children

The objective is to investigate the relation between the levels of two serum adipocytokines (adiponectin and resistin) and non-alcoholic fatty liver disease (NAFLD) in obese children. In this study, 113 obese children were enrolled and divided into 3 groups. Obese group 1 was defined as obese children without any liver abnormality. Obese group 2 was defined as obese children just with fatty infiltration of the liver in ultrasonic appearance and obese group 3 was defined as obese children with liver function abnormality. The controls consisted of 37 nonobese children without endocrine, metabolic or kidney disease. The levels of serum adiponectin and resistin were measured by ELISA method. Insulin resistance by homeostasis model (HOMA-IR), area under curve of glucose (AUCG), serum total cholesterol, triglyceride, alanine aminotransferase, uric acid, HDL-cholesterol, LDL-cholesterol and body mass index (BMI) were measured as well. In obese children, NAFLD were found in 63 cases (55.75%). Serum adiponectin levels of obese children were significantly lower than that of controls (3.63 vs 5.79 microg/mL, P<0.001) while serum resistin levels were not different (P = 0.876). Moreover, serum adiponectin levels in obese group 1 were significantly higher than that of group 2 and 3 (4.24 vs 3.37 and 3.12 microg/mL, all P<0.05) and no difference was found between obese group 2 and obese group 3 (P>0.05). Serum resistin levels among the three obese groups were 4.37 ng/mL, 3.72 ng/mL and 4.24 ng/mL without significant difference (P = 0.592). NAFLD, BMI, gender and HDL-cholesterol were independent determinants of serum adiponectin levels in children analyzed by multiple regression analysis, which explained 33% of the variance. Serum adiponectin levels were inversely associated with BMI, gender and NAFLD (all P<0.05) and were positively associated with HDL-cholesterol levels (P = 0.033). These results suggest that adiponectin might be a protective factor in NAFLD occurrence in obese children, and that the measurement of adiponectin should be part of the standard evaluation of the obese child and may help to evaluate the occurrence of NAFLD.

Nonalcoholic fatty liver disease: is all the fat bad?

Nonalcoholic fatty liver disease is now a major cause of liver disease in developed countries, largely as a result of an epidemic of obesity, diabetes and sedentary lifestyles. This has resulted in raised clinical awareness and diagnostic refinement. The entity encompasses several histologic patterns from benign steatosis to nonalcoholic steatohepatitis, the latter having a significant risk of progressive fibrosis and the development of cirrhosis. Laboratory tests and imaging are not able to distinguish steatosis from steatohepatitis, which requires liver biopsy. However following an assessment of several risk factors, patients can be stratified for the potential risk of fibrosis, allowing the rational use of liver biopsy. This review will describe the various patterns of nonalcoholic fatty liver disease and relate this to disease pathogenesis and progression. Strategies for management, including experimental interventions, will be discussed.

A pilot study of orlistat treatment in obese, non-alcoholic steatohepatitis patients

BACKGROUND

Treatment options for non-alcoholic steatohepatitis (NASH) are limited. Weight loss remains the most recommended therapy. Orlistat is an effective adjunct to dietary weight loss therapy.

AIM

To evaluate the efficacy of orlistat, given for 6 months to patients with obesity and biopsy confirmed NASH.

METHODS

Ten obese patients with biopsy proven NASH were enrolled. Orlistat was given with meals for 6 months. Body Mass Index (BMI), liver enzymes, haemoglobin A1c, fasting lipids and glucose were assessed at baseline and at completion of the study. Paired liver histology was obtained.

RESULTS

Six women and four men were enrolled. The mean weight loss was 22.7 lb and ranged from 0 to 24.3%. The following clinical values significantly improved: mean BMI: 43.4-39.8 (P = 0.007); mean haemoglobin A1c (%): 7.14-5.95 (P = 0.021); mean alanine aminotransferase (ALT) (U/L): 93 -54 (P = 0.009); and mean aspartate aminotransferase (AST) (U/L): 79-48 (P = 0.008). Steatosis improved in six patients, and fibrosis improved in three patients.

CONCLUSIONS

Orlistat therapy and dietary counselling were associated with significant decreases in body weight, haemoglobin A1c, ALT and AST. A 10% or greater reduction in weight improved steatosis and fibrosis as well as haemoglobin A1c levels in the majority of patients treated for 6 months. Controlled trials of longer duration are warranted to assess for histopathologic improvement as well as cost-efficacy in comparison to diet and exercise alone.