Non-alcoholic steatohepatitis (NASH): a disease of emerging identity and importance

Chronic ethanol consumption in mice alters hepatocyte lipid droplet properties

BACKGROUND

Hepatosteatosis is a common pathological feature of impaired hepatic metabolism following chronic alcohol consumption. Although often benign and reversible, it is widely believed that steatosis is a risk factor for development of advanced liver pathologies, including steatohepatitis and fibrosis. The hepatocyte alterations accompanying the initiation of steatosis are not yet clearly defined.

METHODS

Induction of hepatosteatosis by chronic ethanol consumption was investigated using the Lieber-DeCarli (LD) high fat diet model. Effects were assessed by immunohistochemistry and blood and tissue enzymatic assays. Cell culture models were employed for mechanistic studies.

RESULTS

Pair feeding mice ethanol (LD-Et) or isocaloric control (LD-Co) diets for 6 weeks progressively increased hepatocyte triglyceride accumulation in morphological, biochemical, and zonally distinct cytoplasmic lipid droplets (CLD). The LD-Et diet induced zone 2-specific triglyceride accumulation in large CLD coated with perilipin, adipophilin (ADPH), and TIP47. In LD-Co-fed mice, CLD were significantly smaller than those in LD-Et-fed mice and lacked perilipin. A direct role of perilipin in formation of large CLD was further suggested by cell culture studies showing that perilipin-coated CLD were significantly larger than those coated with ADPH or TIP47. LD-Co- and LD-Et-fed animals also differed in hepatic metabolic stress responses. In LD-Et but not LD-Co-fed mice, inductions were observed in the following: microsomal ethanol-oxidizing system [cytochrome P-4502E1 (CYP2E1)], hypoxia response pathway (hypoxia-inducible factor 1 alpha, HIF1α), endoplasmic reticulum stress pathway (calreticulin), and synthesis of lipid peroxidation products [4-hydroxynonenal (4-HNE)]. CYP2E1 and HIF1 α immunostaining localized to zone 3 and did not correlate with accumulation of large CLD. In contrast, calreticulin and 4-HNE immunostaining closely correlated with large CLD accumulation. Importantly, 4-HNE staining significantly colocalized with ADPH and perilipin on the CLD surface.

CONCLUSIONS

These data suggest that ethanol contributes to macrosteatosis by both altering CLD protein composition and inducing lipid peroxide adduction of CLD-associated proteins.

Lycopene prevents development of steatohepatitis in experimental nonalcoholic steatohepatitis model induced by high-fat diet

We investigated the preventive effect of lycopene on nonalcoholic steatohepatitis-induced by high-fat diet in rats. Forty male Sprague-Dawley rats were divided into 4 groups. They were fed standard diet, high-fat diet (HFD), high-fat diet plus lycopene at a dose of 2 mg/kg body weight and the high-fat diet lycopene at a dose of 4 mg/kg BW for a period of 6 weeks. Inflammation, steatosis, α-smooth muscle actin (α-SMA), and cytochrome P450 2E1 (CYP 2E1) expression increased significantly in the rats fed HFD and decreased in the rats administered by lycopene. Significantly elevated levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), tumor necrosis factor (TNF α), and serum and liver malondialdehyde (MDA) were observed in rats fed the high-fat diet as compared to the control rats (P < .01). Supplementation with lycopene lowered serum MDA and tumor necrosis factor (TNF-α) levels and elevated liver GSH level (P < .001). Insulin resistance was higher in the rats fed HFD than in rats supplemented with lycopene. The data indicate that supplementation with lycopene can reduce high-fat diet-induced oxidative stress to the cells.

p62+ Hyaline inclusions in intrahepatic cholangiocarcinoma associated with viral hepatitis or alcoholic liver disease

Mallory bodies (MBs) and hyaline globules (HGs) are recognized as hepatocellular cytoplasmic inclusions in liver diseases. We reviewed 123 intrahepatic cholangiocarcinomas (ICCs) and encountered 16 cases (13.0%) in which cancer cells had MB-type inclusions and/or HG-type inclusions, both of which are positive for p62 and ubiquitin. The HG type was present in all 16 cases, and 5 cases contained the MB type. Of 16 patients, 12 had chronic liver disease that was related to alcoholic abuse in 4, hepatitis B surface antigen-positive in 3, and hepatitis C virus antibody-positive in 8. Viral infection and liver cirrhosis were more common in ICCs with p62+ inclusions (P = .0004 and P = .0199, respectively). Of 16 ICCs, 15 with hyaline inclusions had a peripheral tumor location (P = .0052). On ultrastructural examination, the MB type had an electron-dense fibrillar appearance, while the HG type appeared as rounded masses of granular materials. Our results suggest that intracytoplasmic hyaline bodies occasionally can be found in cholangiocarcinoma with chronic liver disease related to viral hepatitis or alcoholic intake.

Regulation of hepatocyte lipid metabolism and inflammatory response by 25-hydroxycholesterol and 25-hydroxycholesterol-3-sulfate

Dysregulation of lipid metabolism is frequently associated with inflammatory conditions. The mechanism of this association is still not clearly defined. Recently, we identified a nuclear oxysterol, 25-hydroxycholesterol-3-sulfate (25HC3S), as an important regulatory molecule involved in lipid metabolism in hepatocytes. The present study shows that 25HC3S and its precursor, 25-hydroxycholesterol (25HC), diametrically regulate lipid metabolism and inflammatory response via LXR/SREBP-1 and IkappaBalpha/NFkappaB signaling in hepatocytes. Addition of 25HC3S to primary rat hepatocytes decreased nuclear LXR and SREBP-1 protein levels, down-regulated their target genes, acetyl CoA carboxylase 1 (ACC1), fatty acid synthase (FAS), and SREBP-2 target gene HMG reductase, key enzymes involved in fatty acid and cholesterol biosynthesis. 25HC3S reduced TNFalpha-induced inflammatory response by increasing cytoplasmic IkappaBalpha levels, decreasing NFkappaB nuclear translocation, and consequently repressing expression of NFkappaB-dependent genes, IL-1beta, TNFalpha, and TRAF1. NFkappaB-dependent promoter reporter gene assay showed that 25HC3S suppressed luciferase activity in the hepatocytes. In contrast, 25HC elicited opposite effects by increasing nuclear LXR and SREBP-1 protein levels, and by increasing ACC1 and FAS mRNA levels. 25HC also decreased cytoplasmic IkappaBalpha levels and further increased TNFalpha-induced NFkappaB activation. The current findings suggest that 25HC and 25HC3S serve as potent regulators in cross-talk of lipid metabolism and inflammatory response in the hepatocytes.

Betaine improved adipose tissue function in mice fed a high-fat diet: a mechanism for hepatoprotective effect of betaine in nonalcoholic fatty liver disease

Adipose tissue dysfunction, featured by insulin resistance and/or dysregulated adipokine production, plays a central role not only in disease initiation but also in the progression to nonalcoholic steatohepatitis and cirrhosis. Promising beneficial effects of betaine supplementation on nonalcoholic fatty liver disease (NAFLD) have been reported in both clinical investigations and experimental studies; however, data related to betaine therapy in NAFLD are still limited. In this study, we examined the effects of betaine supplementation on hepatic fat accumulation and injury in mice fed a high-fat diet and evaluated mechanisms underlying its hepatoprotective effects. Male C57BL/6 mice weighing 25 +/- 0.5 (SE) g were divided into four groups (8 mice/group) and started on one of four treatments: control diet, control diet supplemented with betaine, high-fat diet, and high-fat diet supplemented with betaine. Betaine was supplemented in the drinking water at a concentration of 1% (wt/vol) (anhydrous). Our results showed that long-term high-fat feeding caused NAFLD in mice, which was manifested by excessive neutral fat accumulation in the liver and elevated plasma alanine aminotransferase levels. Betaine supplementation alleviated hepatic pathological changes, which were concomitant with attenuated insulin resistance as shown by improved homeostasis model assessment of basal insulin resistance values and glucose tolerance test, and corrected abnormal adipokine (adiponectin, resistin, and leptin) productions. Specifically, betaine supplementation enhanced insulin sensitivity in adipose tissue as shown by improved extracellular signal-regulated kinases 1/2 and protein kinase B activations. In adipocytes freshly isolated from mice fed a high-fat diet, pretreatment of betaine enhanced the insulin signaling pathway and improved adipokine productions. Further investigation using whole liver tissues revealed that betaine supplementation alleviated the high-fat diet-induced endoplasmic reticulum stress response in adipose tissue as shown by attenuated glucose-regulated protein 78/C/EBP homologous protein (CHOP) protein abundance and c-Jun NH(2)-terminal kinase activation. Our findings suggest that betaine might serve as a safe and efficacious therapeutic tool for NAFLD by improving adipose tissue function.

The role of fructose in the pathogenesis of NAFLD and the metabolic syndrome

Nonalcoholic fatty liver disease (NAFLD) is the most frequent liver disease worldwide, and is commonly associated with the metabolic syndrome. Secular trends in the prevalence of these diseases may be associated with the increased fructose consumption observed in the Western diet. NAFLD is characterized by two steps of liver injury: intrahepatic lipid accumulation (hepatic steatosis), and inflammatory progression to nonalcoholic steatohepatitis (NASH) (the 'two-hit' theory). In the first 'hit', hepatic metabolism of fructose promotes de novo lipogenesis and intrahepatic lipid, inhibition of mitochondrial beta-oxidation of long-chain fatty acids, triglyceride formation and steatosis, hepatic and skeletal muscle insulin resistance, and hyperglycemia. In the second 'hit', owing to the molecular instability of its five-membered furanose ring, fructose promotes protein fructosylation and formation of reactive oxygen species (ROS), which require quenching by hepatic antioxidants. Many patients with NASH also have micronutrient deficiencies and do not have enough antioxidant capacity to prevent synthesis of ROS, resulting in necroinflammation. We postulate that excessive dietary fructose consumption may underlie the development of NAFLD and the metabolic syndrome. Furthermore, we postulate that NAFLD and alcoholic fatty liver disease share the same pathogenesis.

Proton magnetic resonance spectroscopy and ultrasound for hepatic fat quantification

AIM

The increasing prevalence of fatty liver disease requires routine assessment methods. Proton magnetic resonance spectroscopy ((1)H MRS) is increasingly used for steatosis measurement, but due to cost, is unlikely to become a widely-used screening tool. Ultrasound is cheaper and more widely available, although subject to observer variability. Our aim was to determine the sensitivity and specificity of ultrasound against (1)H MRS, using MRS as a gold standard, for the detection and quantification of hepatic fat content.

METHODS

Fifty adults participated (43 men, seven women) in this study. Hepatic steatosis was assessed by ultrasound and (1)H MRS. Images were graded by two independent radiologists to classify severity and distribution of liver fat.

RESULTS

Ultrasound detected liver fat infiltration in 82% of cases measurable by (1)H MRS, while liver fat was detectable in 44% of cases graded absent by ultrasound. Ultrasound grading was subjective, with the radiologists in agreement in 53% of cases (kappa = 0.39, P = 0.002). Considerable overlap in intrahepatocellular lipid content was observed between different grades: absent (0.0-1.58%), mild (2.2-16.2%), moderate (4.9-26.7%) and severe (8.1-76.8%) steatosis. Ultrasound could not detect liver fat levels below 2% as measured by (1)H MRS Conclusion: Ultrasound is less sensitive than (1)H MRS in detecting very low levels of liver fat content, but is sensitive to fatty infiltration greater than 2%. There is a tendency of higher ultrasound grades to correlate with higher degrees of fatty infiltration, although some overlap exists. Our findings are still consistent with ultrasound being useful as a low cost screening tool.

Serum ferritin is a clinical biomarker in Japanese patients with nonalcoholic steatohepatitis (NASH) independent of HFE gene mutation

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver injury. The spectrum of NAFLD is broad, extending from simple steatosis through nonalcoholic steatohepatitis (NASH). Iron is regarded as a putative element that interacts with oxygen radicals, and high rates of hyperferritinemia and increased hepatic iron stores have been demonstrated in NASH. We investigated serum ferritin concentrations, HFE gene mutations, and insulin resistance in Japanese NASH patients and the diagnostic utility of serum ferritin concentrations as a means of distinguishing NASH. Serum ferritin concentrations were measured in 86 patients with histopathologically verified NAFLD (24 with steatosis and 62 with NASH) and 20 control subjects, they were tested for HFE gene mutations and their insulin resistance was measured. The serum ferritin concentration was significantly higher in the NASH patients than in the patients with simple steatosis (P = 0.006). There was no significant difference between the groups in HFE gene mutation (C282Y, H63D, and S65C), and the serum ferritin level was related with insulin resistance. The area under the ROC curve was 0.732 for distinguishing NASH from simple steatosis (P = 0.005; 95% CI, 0.596-0.856). In conclusion high serum ferritin concentrations are a distinguishing feature of Japanese NASH patients independent of HFE gene mutations.

Comparative evaluation of whole body and hepatic insulin resistance using indices from oral glucose tolerance test in morbidly obese subjects with nonalcoholic Fatty liver disease

Nonalcoholic Fatty Liver Disease (NAFLD) is the hepatic manifestation of metabolic syndrome and is a marker of Insulin Resistance (IR). Euglycemic-hyperinsulinemic clamp is the gold standard for measuring whole body IR (hepatic + peripheral IR). However, it is an invasive and expensive procedure. Homeostasis Model Assessment Index for Insulin Sensitivity (HOMA-IS), Quantitative Insulin Sensitivity Check Index (QUICKI) for hepatic IR and Insulin Sensitivity Index (ISI(0,120)), and Whole Body Insulin Sensitivity Index (WBISI) for whole body IR are the indices calculated after Oral Glucose Tolerance Test (OGTT). We used these indices as noninvasive methods of IR (inverse of insulin sensitivity) estimation and compared hepatic/peripheral components of whole body IR in NAFLD. Methods. 113 morbidly obese, nondiabetic subjects who underwent gastric bypass surgery and intraoperative liver biopsy were included in the study. OGTT was performed preoperatively and the indices were calculated. Subjects were divided into closely matched groups as normal, fatty liver (FL) and Non-Alcoholic Steatohepatitis (NASH) based on histology. Results. Whole body IR was significantly higher in both FL and NASH groups (NAFLD) as compared to Normal, while hepatic IR was higher only in NASH from Normal. Conclusions. FL is a manifestation of peripheral IR but not hepatic IR.

High-sensitivity C-reactive protein and liver enzymes in individuals with Metabolic Syndrome in Talca, Chile

Metabolic syndrome (MS) is a core set of disorders, including abdominal obesity, dyslipidemia, hypertension and hypertriglyceridemia that together predict the development of diabetes type 2 and cardiovascular disease. This study investigated the relationship between liver enzyme levels and high-sensitivity C-reactive protein (hs-CRP) in subjects with and without MS. Alanine-aminotransferase (ALAT), aspartate-aminotransferase (ASAT), γ-glutamyl transferase (GGT) and hs-CRP were measured in 510 subjects, aged 40 to 65 years old. Patients were selected from 1007 subjects from the Research Program for Cardiovascular Disease Risk Factors in Talca, Chile. Results showed that women with MS presented higher liver enzyme levels than those who did not have MS. This was not observed in male patients for the enzymes ALAT and ASAT. However, GGT and hs-PCR levels were higher in male and female patients with MS than in those without MS. In conclusion, it is important to search for the presence of MS when diagnosing fatty liver. Moreover, the presence of liver disease in patients with MS should be further investigated.

A translational view of the genetics of lipodystrophy and ectopic fat deposition

A wide range of lipodystrophy syndromes exist, each with varying clinical presentations, and yet cumulatively they underscore the importance of adipocyte biology in human metabolism. Loss of the ability to retain excess lipids in "classical" adipose tissue stores can lead to the overdevelopment of ectopic fat stores, often creating severe perturbations of both glucose and lipid homeostasis. Linkage analysis and candidate sequencing efforts have successfully identified responsible mutations for multiple forms of lipodystrophy. Recently, the reduction in the cost of DNA sequencing has resulted in discovery of many novel mutations within both known and novel loci. In this review, we present the steps involved in clinical characterization of a suspected lipodystrophy case, an overview of the clinical manifestations, molecular findings, and pathogenic basis of different forms of lipodystrophy, a discussion of therapeutic options for lipodystrophy patients, and an examination of genetic advances that will be used to identify additional pathogenic mechanisms.

Outcomes of liver transplantation in patients with cirrhosis due to nonalcoholic steatohepatitis versus patients with cirrhosis due to alcoholic liver disease

Nonalcoholic steatohepatitis (NASH) is becoming a common cause of liver cirrhosis requiring liver transplantation (LT). Cardiovascular complications related to metabolic syndrome and NASH recurrence in the transplanted liver may affect the outcome of LT in these patients. We compared the outcomes of LT for NASH cirrhosis and alcoholic cirrhosis (ETOH) in a large transplant center. A retrospective chart review was performed for all patients who underwent LT for cryptogenic cirrhosis with the NASH phenotype (the NASH group) or ETOH (the ETOH group) at the University of Miami from January 1997 to January 2007. There was no significant difference in survival between the NASH and ETOH groups, despite a trend toward lower survival in the former (P = 0.1699). Sepsis was the leading cause of posttransplant death in both groups, and it was followed by cardiovascular causes in the NASH group (26% versus 7% in the ETOH group, P = 0.21) and malignancies in the ETOH group (29% versus 0% in the NASH group, P = 0.024). Recurrent steatohepatitis (33% versus 0%, P < 0.0001) and acute rejection (41% versus 23%, P < 0.023) were significantly more frequent in the NASH group than in the ETOH group. There was no difference in graft failure between the groups (24% in the NASH group versus 18% in the ETOH group, P = 0.3973). In conclusion, despite a numerical trend favoring the ETOH group, there were no statistically significant differences in posttransplant survival and cardiovascular mortality between the NASH and ETOH groups. Acute rejection and recurrent steatohepatitis were significantly more frequent in the NASH group but did not lead to higher rates of retransplantation.

Nitric oxide and redox regulation in the liver: Part I. General considerations and redox biology in hepatitis

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are created in normal hepatocytes and are critical for normal physiologic processes, including oxidative respiration, growth, regeneration, apoptosis, and microsomal defense. When the levels of oxidation products exceed the capacity of normal antioxidant systems, oxidative stress occurs. This type of stress, in the form of ROS and RNS, can be damaging to all liver cells, including hepatocytes, Kupffer cells, stellate cells, and endothelial cells, through induction of inflammation, ischemia, fibrosis, necrosis, apoptosis, or through malignant transformation by damaging lipids, proteins, and/or DNA. In Part I of this review, we will discuss basic redox biology in the liver, including a review of ROS, RNS, and antioxidants, with a focus on nitric oxide as a common source of RNS. We will then review the evidence for oxidative stress as a mechanism of liver injury in hepatitis (alcoholic, viral, nonalcoholic). In Part II of this review, we will review oxidative stress in common pathophysiologic conditions, including ischemia/reperfusion injury, fibrosis, hepatocellular carcinoma, iron overload, Wilson's disease, sepsis, and acetaminophen overdose. Finally, biomarkers, proteomic, and antioxidant therapies will be discussed as areas for future therapeutic interventions.

Hyperferritinemia is a risk factor for steatosis in chronic liver disease

AIM

To investigate the relationship between ferritin and steatosis in patients with chronically abnormal liver function tests (LFTs) and high ferritin level.

METHODS

One hundred and twenty-four consecutive patients with hyperferritinemia (male > 300 ng/mL, female > 200 ng/mL) were evaluated; clinical, biochemical and serological data, iron status parameters, HFE gene mutations and homeostasis model assessment score were obtained. Steatosis was graded by ultrasound as absent or present. Histology was available in 53 patients only.

RESULTS

Mean level of ferritin was 881 +/- 77 ng/mL in men and 549 +/- 82 ng/mL in women. The diagnosis was chronic hepatitis C in 53 (42.7%), non-alcoholic fatty liver disease/non-alcoholic steatohepatitis in 57 (45.9%), and cryptogenic liver damage in 14 (11.3%). None was diagnosed as hereditary hemochromatosis (HH). Hepatic siderosis on liver biopsy was present in 17 of 54 (32%) patients; grade 1 in eight and grade 2 in nine. Overall, 92 patients (74.2%) had steatosis. By logistic regression, ferritin and gamma-glutamyltransferase were independent predictors of steatosis. Ferritin levels were significantly related to low platelet count, steatosis and hepatitis C virus infection.

CONCLUSION

In a non-obese cohort of non-alcoholic patients with chronically abnormal LFTs without HH, high serum ferritin level is a risk factor for steatosis.

Preventive effect of a melon extract rich in superoxide scavenging activity on abdominal and liver fat and adipokine imbalance in high-fat-fed hamsters

Studies showed that dietary antioxidants could be a therapy against obesity that is associated with a state of oxidative stress. Thus, this paper investigates whether a dietary ingredient, a melon juice extract rich in superoxide dismutase, would prevent the development of such obesity in hamsters. Five groups received a standard diet or a high-fat diet (HF) plus a daily gavage with water (control) or extract at 0.7, 2.8, or 5.6 mg/day. After 84 days, the higher dose lowered triglyceridemia (68%), production of liver superoxide anion (12%), mitochondrial cytochrome c oxidase activity (40%), lipid and protein oxidation products (35 and 35%, respectively), and leptinemia (99%) and increased adiponectinemia (29%), leading to a concomitant reduction in insulinemia (39%), insulin resistance (41%), and abdominal lipids (25%). The extract triggered a remarkable decrease of liver lipids (73%) and fully prevented the steatohepatitis induced by the HF diet. Chronic consumption of this melon extract may represent a new alternative to reduce obesity induced by a high-fat diet.

Hyperferritinemia is a risk factor for steatosis in chronic liver disease

AIM: To investigate the relationship between ferritin and steatosis in patients with chronically abnormal liver function tests (LFTs) and high ferritin level.

METHODS: One hundred and twenty-four consecutive patients with hyperferritinemia (male > 300 ng/mL, female > 200 ng/mL) were evaluated; clinical, biochemical and serological data, iron status parameters, HFE gene mutations and homeostasis model assessment score were obtained. Steatosis was graded by ultrasound as absent or present. Histology was available in 53 patients only.

RESULTS: Mean level of ferritin was 881 ± 77 ng/mL in men and 549 ± 82 ng/mL in women. The diagnosis was chronic hepatitis C in 53 (42.7%), non-alcoholic fatty liver disease/non-alcoholic steatohepatitis in 57 (45.9%), and cryptogenic liver damage in 14 (11.3%). None was diagnosed as hereditary hemochromatosis (HH). Hepatic siderosis on liver biopsy was present in 17 of 54 (32%) patients; grade 1 in eight and grade 2 in nine. Overall, 92 patients (74.2%) had steatosis. By logistic regression, ferritin and γ-glutamyltransferase were independent predictors of steatosis. Ferritin levels were significantly related to low platelet count, steatosis and hepatitis C virus infection.

CONCLUSION: In a non-obese cohort of non-alcoholic patients with chronically abnormal LFTs without HH, high serum ferritin level is a risk factor for steatosis.

Hepatic lipid metabolism and non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is an increasingly recognized pathology with a high prevalence and a possible evolution to its inflammatory counterpart (non-alcoholic steatohepatitis, or NASH). The pathophysiology of NAFLD and NASH has many links with the metabolic syndrome, sharing a causative factor in insulin resistance. According to a two-hit hypothesis, increased intrahepatic triglyceride accumulation (due to increased synthesis, decreased export, or both) is followed by a second step (or "hit"), which may lead to NASH. The latter likely involves oxidative stress, cytochrome P450 activation, lipid peroxidation, increased inflammatory cytokine production, activation of hepatic stellate cells and apoptosis. However, both "hits" may be caused by the same factors. The aim of this article is to overview the biochemical steps of fat regulation in the liver and the alterations occurring in the pathogenesis of NAFLD and NASH.

The Effect of Metformin and Standard Therapy versus Standard Therapy alone in Nondiabetic Patients with Insulin Resistance and Nonalcoholic Steatohepatitis (NASH): A Pilot Trial

Nonalcoholic steatohepatitis (NASH) is increasing in prevalence and is related to underlying insulin resistance. The aim of this study was to assess the efficacy of metformin on the characteristic histopathologic lesions of NASH. This was a 12-month prospective, randomized, placebo-controlled trial comparing diet and exercise alone to diet, exercise and metformin in nondiabetic patients with insulin resistance and NASH. Patients were randomized to either group A or B. Group A received placebo, dietary counseling, recommendations for weight loss and exercise four times per week. Group B received long-acting metformin 500 mg daily (titrated to 1000 mg daily) plus dietary counseling, recommendations for weight loss and exercise four times per week. Histopathology was assessed at 12 months and biopsies were scored by two pathologists who were blinded to all data. Twenty-three subjects were screened and 19 were randomized to either group A (n ¼10) or group B (n¼ 9). Seven of the 10 subjects in group A completed the study including repeat liver biopsy while all patients in group B completed the study. Body mass index improved in both groups decreasing by 1.7 kg/m(2) in group A and 0.9 kg/m(2) in group B (not significant, control versus treatment). Homeostasis model assessment of insulin resistance scores improved in both groups decreasing by 1.14 in group A and 1.58 in group B (not significant, control versus treatment). No significant difference in histopathology was seen between groups on follow-up liver biopsy. Metformin appeared to have little effect in improvement in liver function tests or liver histology in nondiabetic patients with insulin resistance and NASH. Decrease in BMI through diet and exercise significantly improved HOMA-IR scores, serum aminotransferases and liver histology.

Non-alcoholic steatohepatitis: an overview

Non-alcoholic fatty liver disease (NAFLD) includes a broad spectrum of fat-induced liver injury, ranging from mild steatosis to cirrhosis and liver failure. The presence of obesity and insulin resistance is strongly associated with non-alcoholic fatty liver and a greater risk of advanced disease. We present here a review of the mechanisms involved in the pathogenesis of NAFLD, advances in the diagnosis, and options for treatment.

Clinical trial: pilot study of metformin for the treatment of non-alcoholic steatohepatitis

BACKGROUND

Non-alcoholic steatohepatitis (NASH) is a form of progressive fatty liver disease that is strongly associated with insulin resistance, which suggests that insulin sensitizing agents such as metformin may be beneficial for NASH.

AIM

To assess the effects of metformin on insulin sensitivity, body composition, serum alanine aminotransferase (ALT) levels and liver histology in patients with NASH.

METHODS

Patients underwent liver biopsy, metabolic profiling and imaging studies before and at the end 48 weeks of metformin (2000 mg/day) therapy. The primary endpoint was a three-point improvement in the histological NASH activity index.

RESULTS

Of 28 patients enrolled, 26 (13 females; average age 44 years) completed 48 weeks of treatment and underwent repeat metabolic studies, imaging and liver biopsy. Thirty per cent achieved a histological response. Most patients lost weight, the average being 6 kg. There was a marked association between weight loss and improvements in NASH activity index and ALT levels (both, P < 0.01). Insulin sensitivity also improved, but the degree of change did not correlate with histological improvement.

CONCLUSION

Metformin leads to improvements in liver histology and ALT levels in 30% of patients with NASH, probably by its effects in causing weight loss.

Farnesoid X receptor deficiency induces nonalcoholic steatohepatitis in low-density lipoprotein receptor-knockout mice fed a high-fat diet

Nonalcoholic steatohepatitis (NASH) comprises dysregulation of lipid metabolism and inflammation. Identification of the various genetic and environmental susceptibility factors for NASH may provide novel treatments to limit inflammation and fibrosis in patients. This study utilized a mouse model of hypercholesterolemia, low-density lipoprotein receptor knockout (LDLr(-/-)) mice fed a high-fat diet for 5 months, to test the hypothesis that farnesoid X receptor (FXR) deficiency contributed to NASH development. Either the high-fat diet or FXR deficiency increased serum alanine aminotransferase activity, whereas only FXR deficiency increased bile acid and alkaline phosphatase levels. FXR deficiency and high-fat feeding increased serum cholesterol and triglycerides. Although high fat led to macrosteatosis and hepatocyte ballooning in livers of mice regardless of genotype, no inflammatory infiltrate was observed in the livers of LDLr(-/-) mice. In contrast, in the livers of LDLr(-/-)/FXR(-/-) mice, foci of inflammatory cells were observed occasionally when fed the control diet and were greatly increased when fed the high-fat diet. Consistent with enhanced inflammatory cells, hepatic levels of tumor necrosis factor alpha and intercellular adhesion molecule-1 mRNA were increased by the high-fat diet in LDLr(-/-)/FXR(-/-) mice. In agreement with elevated levels of procollagen 1 alpha 1 and TGF-beta mRNA, type 1 collagen protein levels were increased in livers of LDLr(-/-)/FXR(-/-) mice fed a high-fat diet. In conclusion, FXR deficiency induces pathologic manifestations required for NASH diagnosis in a mouse model of hypercholesterolemia, including macrosteatosis, hepatocyte ballooning, and inflammation, which suggest a combination of FXR deficiency and high-fat diet is a risk factor for NASH development, and activation of FXR may be a therapeutic intervention in the treatment of NASH.

Pattern of expression of adiponectin receptors in human liver and its relation to nonalcoholic steatohepatitis

BACKGROUND

Adiponectin has antisteatosis-anti-inflammatory properties and its circulating levels are reduced in nonalcoholic steatohepatitis (NASH).

METHODS

To assess the role of adiponectin in NASH, we measured expression of adiponectin gene (APM1) and receptors (AdipoR1/AdipoR2) in liver and subcutaneous and visceral fat in subjects with biopsy-proven NASH or pure steatosis (PS). In 103 subjects undergoing gastric bypass or elective abdominal surgery (17 with normal liver histology (C), 52 with PS, and 34 with NASH), RNA was extracted from tissue samples, and quantification of APM1, AdipoR1, and AdipoR2 was carried out by real-time polymerase chain reaction.

RESULTS

In NASH vs C, circulating adiponectin levels (3.6[2.4] vs 5.3[4.3] microg/ml, median[interquartile range], p < 0.05) and adiponectin concentrations, APM1, AdipoR1, and AdipoR2 expression in visceral fat were all reduced (p < or = 0.03). These differences disappeared when adjusting for obesity. In contrast, liver AdipoR1 (1.40 [0.46] vs 1.00 [0.32] of controls) and AdipoR2 expression (1.20 [0.41] vs 0.78 [0.43]) were increased in NASH, and group differences were statistically significant (p < 0.0001 for AdipoR1 and p = 0.0001 for AdipoR2). Results for PS were generally intermediate between NASH and C. Liver receptor expression was reciprocally related to circulating adiponectin (rho = -0.42, p < 0.003 for AdipoR1 and rho = -0.26, p < 0.009 for AdipoR2). In multivariate models adjusting for sex, age, fasting plasma glucose, and obesity, liver enzymes levels were directly related to both AdipoR1 and AdipoR2 expression in liver.

CONCLUSION

In obese patients with NASH, adiponectin receptors are underexpressed in visceral fat-as a likely correlate of obesity-but overexpressed in liver, possibly as a compensatory response to hypoadiponectinemia, and positively associated with liver damage.

Moderate alcohol consumption and lipoprotein-associated phospholipase A2 activity

BACKGROUND AND AIMS

To investigate the effect of moderate alcohol consumption on lipoprotein-associated phospholipase A2 activity, markers of inflammation and oxidative stress and whether these effects are modified by BMI.

METHODS AND RESULTS

Eleven lean (BMI: 18.5-25 kg/m(2)) and 9 overweight (BMI>27 kg/m(2)) men participated in a randomized controlled crossover trial. After consuming 3 cans of beer (40 g ethanol) or alcohol-free beer daily during 3 weeks, fasting blood samples were taken. HDL cholesterol increased by 18.2% (p<0.001) after beer compared to alcohol-free beer, while LDL cholesterol decreased by 7.8% (p=0.008). Lipoprotein-associated phospholipase A2 activity was not different (p=0.23) between beer (47.5+/-0.8) and alcohol-free beer (48.9+/-0.8). High-sensitive C-reactive protein was unaffected, but urinary isoprostanes tended to increase (p=0.09) after beer (114.0+/-6.9) compared to alcohol-free beer (96.9+/-6.5). An interaction between BMI and treatment (p<0.05) on liver enzymes was observed, indicating an increase of liver enzymes after moderate alcohol consumption in overweight men only.

CONCLUSION

Despite profound effects on HDL and LDL cholesterol, moderate alcohol consumption did not affect lipoprotein-associated phospholipase A2 activity. Liver enzymes increased after alcohol consumption in overweight men only, suggesting a less favorable response to moderate alcohol consumption in overweight people.

Increased apoptosis in high-fat diet-induced nonalcoholic steatohepatitis in rats is associated with c-Jun NH2-terminal kinase activation and elevated proapoptotic Bax

Hepatocyte apoptosis in addition to oxidative stress could be a key component in the pathogenesis of nonalcoholic steatohepatitis (NASH). However, the underlying mechanisms of hepatocellular apoptotic response associated with oxidative stress have not been investigated in high-fat diet (HFD)-induced NASH models. In this study, Sprague-Dawley rats were fed either a Lieber-DeCarli control diet (CD; 35% energy from fat) or a HFD (71% energy from fat) for 6 wk. Pathologic lesions, lipid peroxidation products, and apoptotic hepatocytes in the liver were examined. The expressions of hepatic tumor necrosis factor-alpha (TNFalpha) and protein concentrations of cleaved caspase-3, cytochrome p4502E1 (CYP2E1), phosphorylated c-Jun NH(2)-terminal kinase (JNK), Bax, Bcl-2, and Bcl-xl were measured. Results showed that the key histological features of NASH, including steatosis, inflammatory cell infiltration, and ballooning degeneration of hepatocytes, were induced by HFD feeding, with increased hepatic TNFalpha mRNA expression. HFD-fed rats had elevated lipid peroxidation products and CYP2E1 protein in the liver. The apoptotic hepatocytes were significantly greater in livers of rats fed HFD than in those fed CD, and these were associated with a higher level of cleaved caspase-3. In addition, HFD feeding increased both hepatic phosphorylated JNK and pro-apoptotic Bax but did not affect anti-apoptotic Bcl-2 and Bcl-xl compared with CD feeding. These data indicate that the increased oxidative stress and its associated JNK activation as well as an imbalance of pro- and anti-apoptotic proteins in the Bcl-2 family all contribute to high hepatocyte apoptosis that may play an important role in the pathogenesis of NASH in this model.

Serum leptin and soluble leptin receptor in non-alcoholic fatty liver disease

AIM: To determine the role of leptin system in non-alcoholic fatty liver disease (NAFLD) development by delineating the changes in serum levels of leptin and soluble leptin receptor (sOB-R).

METHODS: Blood samples were collected from 30 consecutive patients with liver-biopsy-proven NAFLD and 30 patients with cholecystolithiasis (stationary phase) as controls. Serum leptin levels were determined by radioimmunoassay and concentration of sOB-R was measured by ELISA. Body mass index (BMI) was calculated for all subjects, and serum insulin, C-peptide, and lipoprotein levels were also detected.

RESULTS: Mean serum leptin level and BMI in the NAFLD group were significantly higher than in the controls (both P < 0.001), but mean sOB-R level was lower in the NAFLD group when compared to the controls. Both men and women in the NAFLD group had higher mean serum leptin levels and lower sOB-R levels than did the men and women in the control group (all P < 0.001). There was a significant negative correlation between serum leptin and sOB-R levels (r = -0.725, P < 0.001). Multivariate analysis showed that the percentage of hepatocyte steatosis, sex, BMI, and homeostasis model assessment of insulin resistance (HOMA IR) were independently related to serum leptin levels.

CONCLUSION: Elevated serum leptin seems to be a feature of steatosis, and serum leptin seems to increase as hepatocyte steatosis develops. An enhanced release of leptin is accompanied by an decrease in sOB-R concentration, which suggests higher resistance of peripheral tissues towards the action of leptin.

High prevalence of small intestinal bacterial overgrowth in patients with morbid obesity: a contributor to severe hepatic steatosis

BACKGROUND

With the increasing prevalence of obesity, non-alcoholic fatty liver disease (NAFLD) has become a major cause of liver diseases. Small intestinal bacterial overgrowth (SIBO) could be related to NAFLD. Our aim was to determine the prevalence of SIBO and its relationship with liver lesions in morbidly obese patients.

METHODS

A glucose hydrogen (H(2)) breath test (positive if fasting breath H(2) concentration > 20 ppm and/or an increase of > 10 ppm over baseline within the first 2 h) was performed in obese patients referred for bariatric surgery (body mass index [BMI] > 40 kg/m(2) or > 35 in association with comorbidities) and in healthy non-obese subjects. In obese patients, a surgical liver biopsy was performed.

RESULTS

One hundred and forty-six patients (129 women, age [mean+/-SE]: 40.7 +/- 11.4 years) were prospectively included in the study. The mean BMI was 46.1+/-6.4 kg/m(2). A liver biopsy was available in 137 patients and a breath test in 136. The frequency of positive breath tests was higher in obese patients (24/136, 17.1%) than in healthy subjects (1/40, 2.5%; P=0.031). In the univariate analysis, SIBO was not associated with clinical variables, but tended to be associated with more frequent severe hepatic steatosis (26.3 vs. 10.3%, P=0.127), whereas the frequency of sinusoidal or portal fibrosis, lobular necrosis and non-alcoholic steatohepatitis (NASH) were not different. In the multivariate analysis, SIBO (P=0.005) and the presence of a metabolic syndrome (P=0.006) were independent factors of severe hepatic steatosis.

CONCLUSION

In morbidly obese patients, bacterial overgrowth prevalence is higher than in healthy subjects and is associated with severe hepatic steatosis.

A case-control study of non-alcoholic fatty liver disease in breast cancer

BACKGROUND

Patients with breast cancer sometimes present with increased liver enzymes during follow-up period that may be consistent with hepatic steatosis. This effect known as non-alcoholic fatty liver disease may be associated with the malignancy itself, drugs or some other well-known risk factors that may induce steatosis. We studied the influences of primary disease and treatment on steatosis in patients with breast cancer.

MATERIALS AND METHODS

There were four groups of patients in our study. Group 1: 40 newly diagnosed, previously untreated breast cancer; Group 2: 45 cases of breast cancer treated with systemic therapy; Group 3: 40 cases of ovarian cancer; Group 4: 40 healthy women. Hepatic steatosis was evaluated by sonography by two radiologist, independently. We also evaluated major risk factors, biochemical findings, and influences of treatment on hepatic steatosis.

RESULTS

We detected steatosis in 63%, 72%, 77%, and 48% of patients in groups 1, 2, 3, and 4, respectively. There was a statistically significant difference only between groups 3 and 4 (P = 0.045). However, grade 2 and 3 steatosis were more frequent in breast cancer patients (group 1 and 2), compared with mild steatosis in ovarian cancer patients and healthy women. Although a good correlation was found between tamoxifen use and chemotherapy on development of non-alcoholic fatty liver disease, no association of hepatic steatosis with transaminase levels was found, which might be of help for earlier detection of steatosis. AST/ALT ratio was found to have no impact on the rate of hepatic steatosis, contrary to the literature.

CONCLUSION

Hepatic steatosis, excluding patients with grade 1 steatosis, which may be a normal variant, were more readily detected in patients with breast cancer. This effect was aggravated by use of tamoxifen, but not the chemotherapy. Non-alcoholic fatty liver disease in patients with breast cancer may be associated with the primary tumor itself or some well-known risk factors such as obesity, hyperlipidemia, and diabetes mellitus, which needs to be explored.

Nutritional assessment and hepatic fatty acid composition in non-alcoholic fatty liver disease (NAFLD): a cross-sectional study

BACKGROUND/AIMS

Low hepatic n-6 and n-3 polyunsaturated fatty acid (PUFA) may contribute to steatosis and steatohepatitis and can be affected by diet and oxidative stress.

METHODS

Seventy-three patients referred for elevated liver enzymes and suspected NAFLD were assessed. Nutritional assessment, hepatic FA composition and oxidative stress were compared between these groups: simple steatosis (SS, n=18), steatohepatitis (NASH, n=38) and minimal findings on liver biopsy (MF, n=17).

RESULTS

Patients with NASH had higher: BMI, central obesity, body fat, insulin resistance, dyslipidemia and lower physical activity compared to the other groups. They also had relatively lower hepatic n-3 and n-6 PUFA, a decrease in the ratio of metabolites to essential FA precursors for both n-6 and n-3 FA (eicosapentaenoic+docosahexaenoic/linolenic and arachidonic/linoleic acid ratios) and higher liver lipid peroxides with lower antioxidant power, when compared to MF. Overall, there was no significant difference between SS and NASH in FA composition. Self-reported dietary intake and red blood cell FA composition were similar among the three groups.

CONCLUSIONS

NASH patients have more metabolic abnormalities. This is associated with higher oxidative stress and lower n-3 and n-6 PUFA in the liver in the absence of any differences in dietary FA composition.

Fatty liver in childhood

A parenchimás szervek – mint például a máj – abnormális zsírfelhalmozódását zsíros átalakulásnak nevezzük. A máj elzsírosodásának hátterében a májsejtek zsírfelvevő és zsírleadó folyamatainak egyensúlyzavara áll, miáltal a felesleges triglicerid felhalmozódik a hepatocytákban. Normál esetben a sejtek kb. 5%-a tartalmaz trigliceridet, zsírmáj esetén ez az érték 50% fölé is emelkedhet. 50% alatt májelzsírosodásról, 50% felett zsírmájról beszélünk. Enyhébb esetben nem feltétlenül okoz sejtműködési zavart, súlyosabb formánál azonban igen, sokszor a sejthalál előfutára. A zsírmáj olyan kórállapotnak tekinthető, mely érzékennyé teszi a májat egyéb toxikus hatásokkal szemben. Nem önálló betegség, legtöbbször valamilyen ártalom, egyéb kórfolyamat kísérő jelensége. Önmagában – bizonyos súlyossági fokig (a fibrosis megjelenéséig) – reverzíbilis károsodást jelent, a kiváltó ok megszűnésekor a máj a felesleges triglicerid-tartalmát leadja. Kezelni az alapfolyamatot kell; még nem ismert olyan specifikus gyógyszer, amely a hepatocytákban lerakódott zsírt csökkenti.

Prevalence and risk factors of fatty liver disease in the Shuiguohu district of Wuhan city, central China

BACKGROUND

Fatty liver disease (FLD) is highly prevalent in Western countries, but recent data have shown that FLD is also emerging in China.

AIM

To investigate the prevalence and risk factors of FLD in the Shuiguohu district of Wuhan city, central China, during 1995-2004.

METHODS

12247 individuals (7179 men and 5068 women) over 18 years of age who were living in the area were investigated for FLD in the Zhongnan Hospital of Wuhan University from 1995 to 2004. FLD was determined by the ultrasonographic method. Height, weight, blood pressure, fasting blood sugar, alanine aminotransferase, total cholesterol and triglyceride were determined by routine laboratory methods.

RESULTS

The prevalence of FLD was 12.5% in 1995, and rose gradually to 24.5% by 2003-4. The prevalence was twice as high in men (28.1%) as in women (13.8%), and increased with age in females, and males <60 years of age. Multivariate analysis showed that several risk factors were profoundly associated with the prevalence of FLD, including male sex, old age, obesity, hyperlipidaemia (cholesterol or triglyceride), fasting hyperglycemia and hypertension.

CONCLUSION

The prevalence of FLD in the Shuiguohu district of Wuhan city, central China, was shown to have increased during the 10-year period, 1995 to 2004. The FLD was found to be closely associated with sex, age, obesity and other metabolic syndrome features.

Nonalcoholic fatty liver disease is a risk factor for type 2 diabetes in middle-aged Japanese men

OBJECTIVE

To determine the association between nonalcoholic fatty liver disease and the risk for development of diabetes.

RESEARCH DESIGN AND METHODS

We conducted an observational cohort study in male workers > or = 40 years old in a Japanese company from 1997 to 2005. We excluded workers with alcohol intake > or = 20 g/day and those with impaired glucose tolerance by a 75-g oral glucose tolerance test. The remaining 3,189 workers were classified into fatty liver (FL) and non-FL group based on the findings of abdominal ultrasonography. Both groups were followed for the development of diabetes. Hazard ratio (HR) was determined in Cox proportional hazard analysis. A nested case-control study was conducted to determine the odds ratio (OR).

RESULTS

The average age of participants was 48.0 years at the entry, and the average follow-up period was 4.0 years. The incidence of diabetes in the FL group was 2,073 per 100,000 person-years (65 cases), whereas 452 per 100,000 person-years (44 cases) in the non-FL group. The age- and BMI-adjusted HR of diabetes associated with FL was 5.5 (95% CI 3.6-8.5, P < 0.001). In the nested case-control analysis, the OR adjusted for age and BMI was 4.6 (3.0-6.9, P < 0.001).

CONCLUSIONS

Nonalcoholic fatty liver disease significantly increases the risk of diabetes in middle-aged Japanese men.

Lipid-induced oxidative stress causes steatohepatitis in mice fed an atherogenic diet

Recently, nonalcoholic steatohepatitis (NASH) was found to be correlated with cardiovascular disease events independently of the metabolic syndrome. The aim of this study was to investigate whether an atherogenic (Ath) diet induces the pathology of steatohepatitis necessary for the diagnosis of human NASH and how cholesterol and triglyceride alter the hepatic gene expression profiles responsible for oxidative stress. We investigated the liver pathology and plasma and hepatic lipids of mice fed the Ath diet. The hepatic gene expression profile was examined with microarrays and real-time polymerase chain reactions. The Ath diet induced dyslipidemia, lipid peroxidation, and stellate cell activation in the liver and finally caused precirrhotic steatohepatitis after 24 weeks. Cellular ballooning, a necessary histological feature defining human NASH, was observed in contrast to existing animal models. The addition of a high-fat component to the Ath diet caused hepatic insulin resistance and further accelerated the pathology of steatohepatitis. A global gene expression analysis revealed that the Ath diet up-regulated the hepatic expression levels of genes for fatty acid synthesis, oxidative stress, inflammation, and fibrogenesis, which were further accelerated by the addition of a high-fat component. Conversely, the high-fat component down-regulated the hepatic gene expression of antioxidant enzymes and might have increased oxidative stress.

CONCLUSION

The Ath diet induces oxidative stress and steatohepatitis with cellular ballooning. The high-fat component induces insulin resistance, down-regulates genes for antioxidant enzymes, and further aggravates the steatohepatitis. This model suggests the critical role of lipids in causing oxidative stress and insulin resistance leading to steatohepatitis.

Liver breath tests non-invasively predict higher stages of non-alcoholic steatohepatitis

Effectively assessing subtle hepatic metabolic functions by novel non-invasive tests might be of clinical utility in scoring NAFLD (non-alcoholic fatty liver disease) and in identifying altered metabolic pathways. The present study was conducted on 39 (20 lean and 19 obese) hypertransaminasemic patients with histologically proven NAFLD {ranging from simple steatosis to severe steatohepatitis [NASH (non-alcoholic steatohepatitis)] and fibrosis} and 28 (20 lean and eight overweight) healthy controls, who underwent stable isotope breath testing ([(13)C]methacetin and [(13)C]ketoisocaproate) for microsomal and mitochondrial liver function in relation to histology, serum hyaluronate, as a marker of liver fibrosis, and body size. Compared with healthy subjects and patients with simple steatosis, NASH patients had enhanced methacetin demethylation (P=0.001), but decreased (P=0.001) and delayed (P=0.006) ketoisocaproate decarboxylation, which was inversely related (P=0.001) to the degree of histological fibrosis (r=-0.701), serum hyaluronate (r=-0.644) and body size (r=-0.485). Ketoisocaproate decarboxylation was impaired further in obese patients with NASH, but not in patients with simple steatosis and in overweight controls. NASH and insulin resistance were independently associated with an abnormal ketoisocaproate breath test (P=0.001). The cut-off value of 9.6% cumulative expired (13)CO(2) for ketoisocaproate at 60 min was associated with the highest prediction (positive predictive value, 0.90; negative predictive value, 0.73) for NASH, yielding an overall sensitivity of 68% and specificity of 94%. In conclusion, both microsomal and mitochondrial functions are disturbed in NASH. Therefore stable isotope breath tests may usefully contribute to a better and non-invasive characterization of patients with NAFLD.

Involvement of AMP-activated protein kinase in beneficial effects of betaine on high-sucrose diet-induced hepatic steatosis

Although simple steatosis was originally thought to be a pathologically inert histological change, fat accumulation in the liver may play a critical role not only in disease initiation, but also in the progression to nonalcoholic steatohepatitis and cirrhosis. Therefore, prevention of fat accumulation in the liver may be an effective therapy for multiple stages of nonalcoholic fatty liver disease (NAFLD). Promising beneficial effects of betaine supplementation on human NAFLD have been reported in some pilot clinical studies; however, data related to betaine therapy in NAFLD are limited. In this study, we examined the effects of betaine on fat accumulation in the liver induced by high-sucrose diet and evaluated mechanisms by which betaine could attenuate or prevent hepatic steatosis in this model. Male C57BL/6 mice weighing 20 +/- 0.5 g (means +/- SE) were divided into four groups (8 mice per group) and started on one of four treatments: standard diet (SD), SD+betaine, high-sucrose diet (HS), and HS + betaine. Betaine was supplemented in the drinking water at a concentration of 1% (wt/vol) (anhydrous). Long-term feeding of high-sucrose diet to mice caused significant hepatic steatosis accompanied by markedly increased lipogenic activity. Betaine significantly attenuated hepatic steatosis in this animal model, and this change was associated with increased activation of hepatic AMP-activated protein kinase (AMPK) and attenuated lipogenic capability (enzyme activities and gene expression) in the liver. Our findings are the first to suggest that betaine might serve as a therapeutic tool to attenuate hepatic steatosis by targeting the hepatic AMPK system.

Present and future therapeutic strategies in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is found in individuals who do not drink or abuse alcohol and represents a significant health burden for the general community. NAFLD is often associated with one or more features of the metabolic syndrome and has potential for evolution towards non-alcoholic steatohepatitis (NASH), the necro-inflammatory form of liver steatosis. The most worrisome evolutive events in a subgroup of NASH patients include advanced liver fibrosis, cirrhosis, and hepatocellular carcinoma. Pathophysiology of NAFLD/NASH is complex, but studies point to a pre-eminent role of oxidative stress and lipid peroxidation in the liver, including early mitochondrial dysfunction. Changes follow an insulin resistance status with a background of a chronic pro-inflammatory status due to an excess of visceral adiposity. Although no established therapy exists for NAFLD/NASH, potential therapeutic approaches are discussed in this review.

Oxidative stress-induced risk factors associated with the metabolic syndrome: a unifying hypothesis

Although the biochemical steps linking insulin resistance with the metabolic syndrome have not been completely clarified, mounting experimental and clinical evidence indicate oxidative stress as an attractive candidate for a central pathogenic role since it potentially explains the appearance of all risk factors and supports the clinical manifestations. In fact, metabolic syndrome patients exhibit activation of biochemical pathways leading to increased delivery of reactive oxygen species, decreased antioxidant protection and increased lipid peroxidation. The described associations between increased abdominal fat storage, liver steatosis and systemic oxidative stress, the diminished concentration of nitric oxide derivatives and antioxidant vitamins and the endothelial oxidative damages observed in subjects with the metabolic syndrome definitively support oxidative stress as the common second-level event in a unifying pathogenic view. Moreover, it has been observed that oxidative stress regulates the expression of genes governing lipid and glucose metabolism through activation or inhibition of intracellular sensors. Diet constituents can modulate redox reactions and the oxidative stress extent, thus also acting on nuclear gene expression. As a consequence of the food-gene interaction, metabolic syndrome patients may express different disease features and extents according to the different pathways activated by oxidative stress-modulated effectors. This view could also explain family differences and interethnic variations in determining risk factor appearance. This review mechanistically focused on oxidative stress events leading to individual disease factor appearance in metabolic syndrome patients and their setting for a more helpful clinical approach.

Metabolic conditions of fatty liver in non-diabetic obese women

INTRODUCTION

Steatosis of the liver has a close association with metabolic conditions such as obesity, dyslipidemia and diabetes mellitus. We aimed to determine metabolic features of subjects with different degrees of ultrasonographic steatosis.

MATERIALS AND METHODS

One hundred and thirty non-diabetic obese women were investigated (average age 43.47+/-12.55 yr, range 18-77 yr). They were negative for hepatitis virus and had no history of alcohol usage and diabetes mellitus. All subjects had a complete work-up including clinical examination, anthropometric measurements, laboratory tests, and a routine liver ultrasonographic scanning. Steatosis was graded as absent, mild, moderate, and severe.

RESULTS

A progressive increase was observed in the body mass index (p<0.05), waist circumference (p<0.01), body fat percentage (p<0.05), fasting plasma glucose (p<0.01), triglyceride (p<0.05), alanine aminotransferase (p<0.01), and aspartate aminotransferase (p<0.05) levels as the severity of ultrasonographic fatty liver increased. Also, insulin resistance, which was calculated via homeostasis model assessment, metabolic syndrome, and the prevalence of high alanine aminotransferase levels increased significantly with the degree of the steatosis. On the other hand, hypertriglyceridemia was found to be the independent risk factor for the severity of the steatosis.

CONCLUSION

The present study suggests that liver steatosis may be considered with some metabolic risk factors and particularly in the presence of insulin resistance and metabolic syndrome.

The Combination of S-adenosylmethionine and Dilinoleoylphosphatidylcholine Attenuates Non-alcoholic Steatohepatitis Produced in Rats by a High-Fat Diet

In the pathogenesis of non-alcoholic steatohepatitis (NASH), oxidative stress resulting from free radicals generated by cytochrome P4502E1 (CYP2E1) plays a major role suggesting the importance of antioxidants. The objective of this study was to assess in a high-fat diet (HF) rat model the effects of the combination of s-adenosylmethionine (SAMe) plus dilinoleoylphosphatidylcholine (DLPC) in the treatment of NASH. To test the hypothesis that these two antioxidants are beneficial in NASH, male Sprague-Dawley rats were fed five different diets for six weeks: control, HF diet and HF plus SAMe and DLPC or their combination. As expected, the HF diet significantly increased hepatic triacylglycerols and CYP2E1 levels. However, only the combination diet opposed this effect, consistent with different actions of the two antioxidants. Next, 24 additional rats divided in two groups were fed the HF or the HF+SAMe+DLPC diets for 3 weeks. Dietary intake was similar, but liver triacylglycerols dropped from 76.1+/-6.8 to 49.4+/-3.5 mg/g (p=0.002) and hepatic CYP2E1 mRNA decreased after treatment (p=0.01) with a trend for less CYP2E1 protein. This was accompanied by a 41% reduction of hepatic 4-hydroxynonenal (4-HNE) (p=0.008), reflecting control of oxidative stress. Furthermore, the hepatic inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) mRNA and TNF-alpha protein decreased (p=0.05 and p=0.01 respectively) with attenuation of alpha1(I) procollagen mRNA and type I collagen levels (p=0.01 and p=0.02, respectively). We concluded that the combination SAMe+DLPC might be beneficial in NASH by reducing oxidative stress and associated liver injury.

Genetic forms of the cardiometabolic syndrome: what can they tell the clinician?

A well-worn medical aphorism states that "when you hear hoof beats, think of a horse and not a zebra." When applying this principle to the cardiometabolic syndrome (CMS), the horse would be represented by the prevalent CMS phenotype that affects approximately 30% of individuals in Westernized societies, while the zebra is represented by very rare conditions--such as lipodystrophy syndromes--that share some features with the more prevalent CMS. For instance, familial partial lipodystrophy types 2 and 3 result from heterozygous mutations in LMNA, encoding nuclear lamin A/C, and in PPARG, encoding peroxisome proliferator-activated receptor (PPAR)-gamma, respectively. Patients with either subtype of partial lipodystrophy exhibit an increased ratio of central to peripheral fat stores, dysglycemia, dyslipidemia, and hypertension, with predisposition for developing insulin-resistant diabetes and atherosclerosis end points. Sometimes, however, the zebra serves as a model that can help us understand the horse, so that the rare partial lipodystrophies might offer some insight into pathogenesis and treatment of the more prevalent CMS.

Endothelial dysfunction in Turkish patients with non-alcoholic fatty liver disease

BACKGROUND

The components of the metabolic syndrome are closely related with endothelial dysfunction, which is a pathophysiological issue of cardiovascular diseases. Non-alcoholic fatty liver disease (NAFLD) is considered as one of the components of the metabolic syndrome. The aim of this study was to evaluate the endothelial-dependent dilatation (EDD) and endothelial-independent dilatation (EID) of the brachial artery in NAFLD.

METHODS

Fifteen non-alcoholic steatohepatitis (NASH), 17 patients with simple steatosis and 16 healthy subjects formed the study group. Non-alcoholic fatty liver disease group was composed of patients admitted to the gastroenterology outpatient clinic because of increased liver enzymes. Endothelial functions of the brachial artery were evaluated by vascular ultrasound. EDD was assessed by establishing reactive hyperaemia, and EID was determined by using sublingual nitrate.

RESULTS

No statistical difference for the basal diameter of brachial artery was found between the groups (P = 0.49). The values for EDD and EID were significantly different across all three groups (P < 0.0001 and P < 0.0001, respectively). EDD and EID were significantly lower in NASH compared with simple steatosis (P = 0.01 and P < 0.01, respectively). However, there was no statistical significance for EDD and EID in simple steatosis groups compared with controls (P = 0.58 and P = 0.98, respectively).

CONCLUSIONS

Our study showed that patients with NASH had significantly worse endothelial dysfunction compared with patients with simple steatosis and healthy subjects. The treatment strategies with ameliorative effects for endothelial dysfunction might be effective for delaying the development of cardiovascular complications in NAFLD.

Combining ursodeoxycholic acid or its NO-releasing derivative NCX-1000 with lipophilic antioxidants better protects mouse hepatocytes against amiodarone toxicity

Nonalcoholic steatohepatitis (NASH) is a common and potentially severe form of liver disease. This study aimed to determine the effect of ursodeoxycholic acid and its NO-releasing derivative NCX-1000 alone or in combination with antioxidants on cultured mouse hepatocytes treated with amiodarone to mimic certain aspects of hepatocyte injury found in NASH. Isolated mouse hepatocytes were incubated with ursodeoxycholic acid or NCX-1000 (0–100 μmol/L) combined or not combined with the hydrophilic antioxidants butylated hydroxytoluene and ascorbic acid (0–100 μmol/L) or with the lipophilic antioxidant α-tocopherol (0–100 μmol/L) 15 min before adding amiodarone (50 μmol/L) to the culture medium. Twenty hours later, necrosis, apoptosis, superoxide anion production, and malondialdehyde levels were assessed in cultured cells. Amiodarone led to a dose-dependent decrease in cell viability with an LD50 of 50 μmol/L and increased production of superoxide anion and lipid peroxidation. NCX-1000 showed a better protective potential than ursodeoxycholic acid against the toxic effects of amiodarone. The hydrophilic antioxidants had no effect on the toxicity of amiodarone, whereas α-tocopherol at a concentration >100 μmol/L almost completely suppressed it. Ursodeoxycholic acid and NCX-1000 protection was additive only when they were combined with α-tocopherol, not with butylated hydroxytoluene or ascorbic acid. In addition, all the antioxidants tested reduced the superoxide anion detected, but only α-tocopherol prevented lipid peroxidation induced by amiodarone. The combination of lipophilic antioxidants with ursodeoxycholic acid or NCX-1000 enhances their protective potential and could represent an interesting therapeutic approach to explore for the treatment of NASH.

Cholesterol-fed rabbit as a unique model of nonalcoholic, nonobese, non-insulin-resistant fatty liver disease with characteristic fibrosis

BACKGROUND

The number of patients suffering from metabolic syndrome is increasing rapidly. Metabolic syndrome causes severe pathological changes in various organs, including the liver, and its main phenotype is nonalcoholic fatty liver disease (NAFLD). NAFLD has a broad spectrum ranging from simple fatty change to severe steatohepatitis with marked fibrosis. Recently, several experimental animal models for NAFLD have been proposed. However, most were established by rather artificial conditions such as genetic alteration. In the present study, we tried to establish a unique animal model mimicking some of the physiopathological features of NAFLD using high-cholesterol-fed rabbits.

METHODS

Male rabbits fed with standard rabbit food containing 1% cholesterol for 8 weeks and 12 weeks were compared to controls (six rabbits/group). The weight of food was strictly restricted to 100 g/rabbit per day.

RESULTS

Body weights and fasting plasma insulin levels showed no significant differences among the groups. In contrast, characteristic fine fibrosis was extended from perivenular to pericellular areas, and microvesicular fatty change with ballooning degeneration was observed in perivenular areas in livers of the cholesterol-fed rabbits. Increase of serum cholesterol level, activation of hepatic stellate cells, and exposure to oxidative stress were also recognized.

CONCLUSIONS

Cholesterol-fed rabbits share several physiopathological features of NAFLD. Because this model did not show insulin resistance or obesity, it may be useful for elucidating the mechanism of NAFLD related mainly to hyperlipidemia.