Lack of evidence for the pathogenic role of iron and HFE gene mutations in Brazilian patients with nonalcoholic steatohepatitis

The Role of STAMP2 in Pathogenesis of Chronic Diseases Focusing on Nonalcoholic Fatty Liver Disease: A Review

Nonalcoholic fatty liver disease (NAFLD) is a major health issue. NAFLD can progress from simple hepatic steatosis to nonalcoholic steatohepatitis (NASH). NASH can progress to cirrhosis or hepatocellular carcinoma. Unfortunately, there is no currently approved pharmacologic therapy for NAFLD patients. The six transmembrane protein of prostate 2 (STAMP2), a metalloreductase involved in iron and copper homeostasis, is well known for its critical role in the coordination of glucose/lipid metabolism and inflammation in metabolic tissues. We previously demonstrated that hepatic STAMP2 could be a suitable therapeutic target for NAFLD. In this review, we discuss the emerging role of STAMP2 in the dysregulation of iron metabolism events leading to NAFLD and suggest therapeutic strategies targeting STAMP2.

Hepatic STAMP2 mediates recombinant FGF21-induced improvement of hepatic iron overload in nonalcoholic fatty liver disease

Although previous studies have shown that the administration of fibroblast growth factor 21 (FGF21) reverses hepatic steatosis, the mechanism by which FGF21 exerts a therapeutic effect on nonalcoholic fatty liver disease (NAFLD) is not yet entirely understood. We previously demonstrated that hepatic six transmembrane protein of prostate 2 (STAMP2) may represent a suitable target for NAFLD. We investigated the mechanism underlying the therapeutic effect of recombinant FGF21 on NAFLD, focusing on the involvement of hepatic STAMP2. In this study, we used human nonalcoholic steatosis patient pathology samples, C57BL/6 mice for a high-fat diet (HFD)-induced in vivo NAFLD model, and used human primary hepatocytes and HepG2 cells for oleic acid (OA)-induced in vitro NAFLD model. We observed that recombinant FGF21 treatment ameliorated hepatic steatosis and insulin resistance through the upregulation of STAMP2 expression. We further observed hepatic iron overload (HIO) and reduced iron exporter, ferroportin expression in the liver samples obtained from human NAFLD patients, and HFD-induced NAFLD mice and in OA-treated HepG2 cells. Importantly, recombinant FGF21 improved HIO through the hepatic STAMP2-mediated upregulation of ferroportin expression. Our data suggest that hepatic STAMP2 may represent a suitable therapeutic intervention target for FGF21-induced improvement of NAFLD accompanying HIO.

Serum hepcidin levels are related to serum markers for iron metabolism and fibrosis stage in patients with chronic hepatitis B: A cross-sectional study

BACKGROUND AND STUDY AIMS

The clinical significance of serum parameters of iron metabolism and hepcidin in liver disease remains unknown. Therefore, this study aimed to evaluate the association of serum hepcidin levels with fibrosis stage and serum iron parameters in patients with chronic hepatitis B (CHB).

PATIENTS AND METHODS

This cross-sectional study included 126 treatment-naïve patients with CHB (median age, 39.0 years; 64.3% males) who were positive for hepatitis B surface antigen and 23 healthy controls (median age, 33.0 years; 52.2% males). Data on patient demographics, serum hepcidin levels, liver function tests and serum iron parameters and liver biopsy findings including fibrosis grade, histological activity index (HAI) and liver iron level were recorded.

RESULTS

The median (minimum-maximum) serum hepcidin levels were significantly lower in the CHB group than in the control group [71.2 (13.3-672.7) vs. 657.5 (201.7-2714.2) pg/mL, p < 0.001]. Higher fibrosis stage was associated with higher transferrin saturation (p = 0.029), serum ferritin level (p < 0.001) and viral load (p < 0.001). Fibrosis stage and HAI were positively correlated with ferritin (r = 0.407, p < 0.001 and r = 0.415, p < 0.001, respectively) and transferrin saturation (r = 0.219, p = 0.026 and r = 0.290, p = 0.003, respectively) levels, whereas hepcidin level was negatively correlated with fibrosis stage (r = -0.175, p = 0.051), viral load (r = -0.209, p = 0.020) and ferritin level (r = -0.244, p = 0.006) level. There were no significant differences in serum iron level, total iron binding capacity and liver iron level among patients with different stages of fibrosis.

CONCLUSION

Reduced hepcidin levels and elevated transferrin saturation and ferritin levels are linked to fibrosis severity and HAI in patients with CHB.

Serum Markers of Iron Metabolism in Chronic Liver Diseases

BACKGROUND:

Disorders in the metabolism of iron in the direction of iron overload are observed not only in primary hemochromatosis but also in some chronic liver diseases other aetiology. Elevation of serum iron, ferritin and transferrin saturation is reported in nonalcoholic fatty liver disease and alcohol, chronic hepatitis C and liver cirrhosis.

AIM:

Aim of the study was to evaluate and compare the frequency of the iron serum markers in patients with various chronic liver diseases.

MATERIAL AND METHODS:

The study included a total of 246 persons -186 patients with chronic liver disease without cirrhosis (-115 men, women -71; average age of 50.41 ± 12.85, from 23 to 77 years) and 60 healthy controls (-30 men, women -30, middle-aged 50.50 ± 11.31, from 29 to 83 years). Medical history, physical examination and demographic data including height, weight, laboratory and instrumental studies were performed.

RESULTS:

The highest incidence of elevated serum iron, transferrin saturation and ferritin and decreased serum hepcidin found in cases of alcoholic liver disease (ALD), nonalcoholic fatty liver disease (NAFLD) and chronic hepatitis C (CHC).

CONCLUSION:

Finally, analysis of the changes in serum markers of iron metabolism shows that the difference between healthy and sick with liver disease is primarily due to changes in alcoholic and nonalcoholic fatty liver disease, particularly steatohepatitis, and chronic hepatitis C.

Systematic review of genetic association studies involving histologically confirmed non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease has an increasing prevalence in Western countries, affecting up to 20% of the population.

Iron overload causes oxidative stress and impaired insulin signaling in AML-12 hepatocytes

BACKGROUND

Iron overload is associated with increased severity of nonalcoholic fatty liver disease (NAFLD) including progression to nonalcoholic steatohepatitis and hepatocellular carcinoma.

AIMS

To identify potential role(s) of iron in NAFLD, we measured its effects on pathways of oxidative stress and insulin signaling in AML-12 mouse hepatocytes.

METHODS

Rapid iron overload was induced with 50 μM ferric ammonium citrate and 8-hydroxyquinoline. Insulin response was measured by Western blot of phospho-protein kinase B. Lipid content was determined by staining with Oil Red O. Reactive oxygen species (ROS) were measured by flow cytometry using 5-(and 6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate. Oxidative stress was measured by Western blots for phospho-jnk and phospho-p38.

RESULTS

Iron increased ROS (p < 0.001) and oxidative stress (p < 0.001) and decreased insulin signaling by 33 % (p < 0.001). Treatment with stearic or oleic acids (200 μM) increased cellular lipid content and differentially modulated effects of iron. Stearic acid potentiated iron-induced ROS levels by two-fold (p < 0.05) and further decreased insulin response 59 % (p < 0.05) versus iron alone. In contrast, cells treated with oleic acid were protected against iron-mediated injury; ROS levels were decreased by half (p < 0.01) versus iron alone while insulin response was restored to control (untreated) levels. The anti-oxidant curcumin reduced effects of iron on insulin signaling, ROS, and oxidative stress (p < 0.01). Curcumin was similarly effective in cells treated with both stearic acid and iron.

CONCLUSIONS

An in vitro model of NAFLD progression is described in which iron-induced oxidative stress inhibits insulin signaling. Pathophysiological effects of iron were increased by saturated fat and decreased by curcumin.

Genetics of nonalcoholic Fatty liver disease: an overview

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in the world today. Its incidence in adults and children is rising rapidly due to the ongoing epidemics of obesity and type 2 diabetes. Hence, it has become a global public health issue. Environmental factors have been found to play a major role in the etiology of NAFLD, especially for genetically susceptible populations. Among these, one of the most important factors is junk food, especially the typical "Western-style" diet rich in simple carbohydrates, saturated fat, and highly processed food materials. Genetic predisposition to NAFLD does occur; however, a precise definition of genetic factors responsible for NAFLD is still lacking. Specific variants of different genes have been shown to present a risk for NAFLD. Genetic studies might be helpful in the management of the disease by developing novel treatment strategies based on individual's genotype.

Lower serum hepcidin and greater parenchymal iron in nonalcoholic fatty liver disease patients with C282Y HFE mutations

Hepcidin regulation is linked to both iron and inflammatory signals and may influence iron loading in nonalcoholic steatohepatitis (NASH). The aim of this study was to examine the relationships among HFE genotype, serum hepcidin level, hepatic iron deposition, and histology in nonalcoholic fatty liver disease (NAFLD). Single-nucleotide polymorphism genotyping for C282Y (rs1800562) and H63D (rs1799945) HFE mutations was performed in 786 adult subjects in the NASH Clinical Research Network (CRN). Clinical, histologic, and laboratory data were compared using nonparametric statistics and multivariate logistic regression. NAFLD patients with C282Y, but not H63D mutations, had lower median serum hepcidin levels (57 versus 65 ng/mL; P = 0.01) and higher mean hepatocellular (HC) iron grades (0.59 versus 0.28; P < 0.001), compared to wild-type (WT) subjects. Subjects with hepatic iron deposition had higher serum hepcidin levels than subjects without iron for all HFE genotypes (P < 0.0001). Hepcidin levels were highest among patients with mixed HC/reticuloendothelial system cell (RES) iron deposition. H63D mutations were associated with higher steatosis grades and NAFLD activity scores (odds ratio [OR], ≥1.4; 95% confidence interval [CI]: >1.0, ≤2.5; P ≤ 0.041), compared to WT, but not with either HC or RES iron. NAFLD patients with C282Y mutations had less ballooning or NASH (OR, ≤0.62; 95% CI: >0.39, <0.94; P ≤ 0.024), compared to WT subjects.

CONCLUSIONS

The presence of C282Y mutations in patients with NAFLD is associated with greater HC iron deposition and decreased serum hepcidin levels, and there is a positive relationship between hepatic iron stores and serum hepcidin level across all HFE genotypes. These data suggest that body iron stores are the major determinant of hepcidin regulation in NAFLD, regardless of HFE genotype. A potential role for H63D mutations in NAFLD pathogenesis is possible through iron-independent mechanisms.

Interactions between hepatic iron and lipid metabolism with possible relevance to steatohepatitis

The liver is an important site for iron and lipid metabolism and the main site for the interactions between these two metabolic pathways. Although conflicting results have been obtained, most studies support the hypothesis that iron plays a role in hepatic lipogenesis. Iron is an integral part of some enzymes and transporters involved in lipid metabolism and, as such, may exert a direct effect on hepatic lipid load, intrahepatic metabolic pathways and hepatic lipid secretion. On the other hand, iron in its ferrous form may indirectly affect lipid metabolism through its ability to induce oxidative stress and inflammation, a hypothesis which is currently the focus of much research in the field of non-alcoholic fatty liver disease/non-alcoholic steatohepatitis (NAFLD/NASH). The present review will first discuss how iron might directly interact with the metabolism of hepatic lipids and then consider a new perspective on the way in which iron may have a role in the two hit hypothesis for the progression of NAFLD via ferroportin and the iron regulatory molecule hepcidin. The review concludes that iron has important interactions with lipid metabolism in the liver that can impact on the development of NAFLD/NASH. More defined studies are required to improve our understanding of these effects.

Iron metabolism in Nonalcoholic Fatty Liver Disease

Non-Alcoholic Fatty Liver Disease (NAFLD) is a common worldwide clinical and major public health problem affecting both adults and children in developed nations. Increased hepatic iron stores are observed in about one-third of adult NAFLD patients. Iron deposition may occur in parenchymal and/or non-parenchymal cells of the reticuloendothelial system (RES). Similar patterns of iron deposition have been associated with increased severity of other chronic liver diseases including HCV infection and dysmetabolic iron overload, suggesting there may be a common mechanism for hepatic iron deposition in these diseases. In NAFLD, iron may potentiate the onset and progression of disease by increasing oxidative stress and altering insulin signaling and lipid metabolism. The impact of iron in these processes may depend upon the sub-cellular location of iron deposition in hepatocytes or RES cells. Iron depletion therapy has shown efficacy at reducing serum aminotransferase levels and improving insulin sensitivity in subjects with NAFLD.

Iron overload in nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is a major causative agent of chronic liver disease worldwide, but the actual mechanisms responsible for liver injury remain unclear. NAFLD includes a spectrum of clinical entities ranging from simple steatosis to nonalcoholic steatohepatitis (NASH) with possible evolution to cirrhosis and hepatocellular carcinoma. Iron is considered a putative element that interacts with oxygen radicals in inducing liver damage/fibrosis and insulin resistance. The role of hepatic iron in the progression of NASH remains controversial, but in some patients, iron may have a role in the pathogenesis of NASH. Though genetic factors, insulin resistance, dysregulation of iron-regulatory molecules, erythrophagocytosis by Kupffer cells may be responsible for hepatic iron accumulation in NASH, exact mechanisms involved in iron overload remain to be clarified. Iron reduction therapy such as phlebotomy or iron-restricted diet may be promising in patients with NAFLD/NASH to reduce hepatic injury as well as insulin resistance. Larger controlled trials of longer duration are warranted to assess the long-term clinical benefit of phlebotomy and/or iron-restricted diet in NAFLD/NASH.

Hemochromatosis gene and nonalcoholic fatty liver disease: a systematic review and meta-analysis

BACKGROUND & AIMS

Previous studies examining the relationship between the C282Y and H63D HFE mutations and presence of nonalcoholic fatty liver disease (NAFLD) have yielded conflicting results. The goal of this study was to systematically evaluate and summarize data on the association between these two variants and the presence of NAFLD.

METHODS

The authors searched EMBASE and PUBMED from August 1, 1996 to August 12, 2010. Two investigators independently conducted data abstraction. Ethnic specific weighted prevalence was calculated and pooled odds ratios were estimated using the random effects model.

RESULTS

From 2542 references, the authors included 16 case-control studies and 14 case-only studies, or 2610 cases and 7298 controls. The majority of the studies came from Caucasian populations (2287 cases and 4275 controls). The weighted prevalence of HFE mutations in cases was comparable to controls. The meta-analysis was restricted to Caucasians only because of the small sample size of non Caucasian participants. The pooled odds ratio for the presence of any HFE genetic variant in cases was 1.03 (95%CI: 0.90, 1.17; I(2): 65.8%, 95%CI: 38.5, 81.0). The presence of other genotypes and secondary analyses yielded similar non significant findings.

CONCLUSIONS

Our systematic review does not support an association between the HFE genetic variants and the presence of NAFLD.

An epidemiologic study on the incidence and significance of HFE mutations in a Korean cohort with nonalcoholic fatty liver disease

BACKGROUND/AIM

The incidence and significance of HFE mutations (C282Y, H63D, and S65C) in nonalcoholic fatty liver disease (NAFLD) has not been investigated in Korea.

METHODS

Mutation analysis of HFE gene and measurement of blood iron indices were carried out in 125 NAFLD patients and 221 controls.

RESULTS

Neither C282Y nor S65C gene mutations were detected. The prevalence of the H63D mutation was higher in the NAFLD group (14.4%) than in the controls (7.2%) (P=0.032). The estimated odds ratio (OR) of NAFLD for H63D mutations was 3.09 (P=0.008) by multivariate analysis, and age, gender, obesity, diabetes mellitus, and hypercholesterolemia were independent variables associated with NAFLD. However, in the multivariate analysis containing interaction of the types of HFE mutations and gender, the prevalence of the H63D mutation was significantly higher in the male NAFLD group than in the male control group (OR=5.51, P=0.007); the difference of the prevalence between the NAFLD and the control group in females was not significant. The NAFLD patients with H63D mutations had higher levels of TS than those with the wild type (OR=3.14, P=0.048) by the multivariate analysis. A higher TS was significantly associated with the lower body mass index only in the male NAFLD group by multivariate analysis (OR=0.67, P=0.002).

CONCLUSIONS

The presence of H63D mutations was an independent factor associated with NAFLD and elevated TS. Therefore, the H63D mutation may increase susceptibility to NAFLD probably associated with peripheral iron overload, especially in males.

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.

Hepatic iron overload and risk of hepatocellular carcinoma in cirrhosis

Iron accumulation in the liver is considered to be a co-factor for progression of liver disease. Iron overload can enhance the effects of oxidative stress and influence the natural history of patients with cirrhosis, exposing them to a higher risk of hepatocellular carcinoma. The results of clinical studies designed to assess the impact of liver iron content on the risk of tumor development have remained controversial for some time. It is known that common factors can affect both liver iron overload and the risk of cancer, necessitating multivariate analyses of these features in large cohorts of cirrhotic patients. Furthermore, the causes and consequences of hepatic iron overload appear to depend on the cause of the underlying liver disease. Thus, the only solid evidence of a relationship between liver iron overload and event occurrence has come from longitudinal studies conducted in homogeneous cohorts of patients with cirrhosis. So far, the available data suggest that iron accumulation in the liver is an independent risk factor for hepatocellular carcinoma in patients with alcoholic cirrhosis and/or nonalcoholic hepatosteatosis, but not in those with viral hepatitis C cirrhosis.

Role of hepatic iron in non-alcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) includes a spectrum of clinical entities ranging from simple steatosis to non-alcoholic steatohepatitis (NASH) with possible evolution to cirrhosis and hepatocellular carcinoma. Iron is considered a putative element that interacts with oxygen radicals in inducing liver damage and fibrosis. The role of hepatic iron in the progression of NASH remains controversial, but in some patients, iron may have a role in the pathogenesis of NASH. Though genetic factors, insulin resistance, dysregulation of iron-regulatory molecules, erythrophagocytosis by Kupffer cells may be responsible for hepatic iron accumulation in NASH, exact mechanisms involved in iron overload remain to be clarified. Iron reduction therapy such as phlebotomy or dietary iron restriction may be promising in patients with NASH/NAFLD to reduce insulin resistance as well as serum transaminase activities.

Co-factors in liver disease: the role of HFE-related hereditary hemochromatosis and iron

The severity of liver disease and its presentation is thought to be influenced by many host factors. Prominent among these factors is the level of iron in the body. The liver plays an important role in coordinating the regulation of iron homeostasis and is involved in regulating the level of iron absorption in the duodenum and iron recycling by the macrophages. Iron homeostasis is disturbed by several metabolic and genetic disorders, including various forms of hereditary hemochromatosis. This review will focus on liver disease and how it is affected by disordered iron homeostasis, as observed in hereditary hemochromatosis and due to HFE mutations. The types of liver disease covered herein are chronic hepatitis C virus (HCV) infection, alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), end-stage liver disease, hepatocellular carcinoma (HCC) and porphyria cutanea tarda (PCT).

SLC40A1 c.1402G-->a results in aberrant splicing, ferroportin truncation after glycine 330, and an autosomal dominant hemochromatosis phenotype

BACKGROUND/AIMS

To determine the molecular basis of a mild hemochromatosis phenotype in a man of Scottish-Irish descent.

METHODS

We sequenced genomic DNA to detect mutations of HFE, SLC40A1, TFR2, HAMP, and HFE2. RNA isolated from blood mononuclear cells was used to make cDNA. RT-PCR was performed to amplify ferroportin from cDNA, and amplified products were visualized by electrophoresis and sequenced.

RESULTS

The proband was heterozygous for the novel mutation c.1402G-->A (predicted G468S) in exon 7 of the ferroportin gene (SLC40A1). Located in the last nucleotide before the splice junction, this mutation results in aberrant splicing to a cryptic upstream splice site located at nt 990 within the same exon. This causes truncation of ferroportin after glycine 330 and the addition of 4 irrelevant amino acids before terminating. The truncated ferroportin protein, missing its C-terminal 241 amino acids, would lack all structural motifs beyond transmembrane region 7. The patient was also heterozygous for the common HFE H63D polymorphism, but did not have coding region mutations in TFR2, HAMP, or HFE2.

CONCLUSIONS

We conclude that this patient represents a unique example of hemochromatosis due to a single base-pair mutation of SLC40A1 that results in aberrant splicing and truncation of ferroportin.

Prevalence of the hemochromatosis gene mutation in patients with nonalcoholic steatohepatitis and correlation with degree of liver fibrosis

BACKGROUND

Nonalcoholic steatohepatitis is a chronic liver disease with a high prevalence in the general population and a potential to evolve into cirrhosis. It is speculated that iron overload could be associated with liver injury and unfavorable progress in affected patients.

AIMS

To evaluate the prevalence of mutation of the hemochromatosis gene (HFE) in patients with nonalcoholic steatohepatitis and to correlate it with histological findings in liver specimens.

PATIENTS AND METHODS

Twenty-nine patients with nonalcoholic steatohepatitis were evaluated. The presence of mutation in the hemochromatosis gene (C282Y and H63D) was tested in all patients and its result was evaluated in relation to hepatic inflammatory activity, presence of fibrosis, and iron overload in the liver. The control group was composed of 20 patients with normal liver function tests and 20 patients infected with the hepatitis C virus, with elevated serum levels of aminotransferases and with chronic hepatitis as shown by biopsy.

RESULTS

Mutation of the hemochromatosis gene (C282Y and/or H63D) was diagnosed in 16 (55.2%) patients with nonalcoholic steatohepatitis, in 12 (60%) patients with hepatitis C and in 8 (40%) patients with no liver disease. No association was found between the presence of mutation and inflammatory activity, nor with the presence of fibrosis in patients with nonalcoholic steatohepatitis. An association was found between the presence of mutation and the occurrence of iron overload in liver, but there was no association between liver iron and the occurrence of fibrosis.

CONCLUSIONS

The findings suggest that iron does not play a major role in the pathogenesis and progression of nonalcoholic steatohepatitis, and routine tests of the hemochromatosis gene mutation in these patients should not be recommended.

HFE gene in primary and secondary hepatic iron overload

Distinct from hereditary haemochromatosis, hepatic iron overload is a common finding in several chronic liver diseases. Many studies have investigated the prevalence, distribution and possible contributory role of excess hepatic iron in non-haemochromatotic chronic liver diseases. Indeed, some authors have proposed iron removal in liver diseases other than hereditary haemochromatosis. However, the pathogenesis of secondary iron overload remains unclear. The High Fe (HFE) gene has been implicated, but the reported data are controversial. In this article, we summarise current concepts regarding the cellular role of the HFE protein in iron homeostasis. We review the current status of the literature regarding the prevalence, hepatic distribution and possible therapeutic implications of iron overload in chronic hepatitis C, hepatitis B, alcoholic and non-alcoholic fatty liver diseases and porphyria cutanea tarda. We discuss the evidence regarding the role of HFE gene mutations in these liver diseases. Finally, we summarize the common and specific features of iron overload in liver diseases other than haemochromatosis.

HFE C282Y mutations are associated with advanced hepatic fibrosis in Caucasians with nonalcoholic steatohepatitis

Previous studies examining the relationship between HFE mutations and severity of nonalcoholic steatohepatitis (NASH) have been limited by small sample size or ascertainment bias. The aim of this study was to examine the relationship between HFE mutations and histological severity in a large North American multicenter cohort with NASH. Data from 126 NASH patients were collected from 6 North American centers. Liver biopsy and genotyping for the C282Y and H63D HFE mutations were performed in all subjects. Serum transferrin-iron saturation and ferritin levels as well as hepatic iron content were recorded whenever available. Univariate and multivariate logistic regression analyses were performed to identify factors associated with advanced hepatic fibrosis. The prevalence of heterozygous C282Y and H63D HFE mutations was 14.3% and 21.4%, respectively, in the overall cohort. Among Caucasians, C282Y heterozygotes were more likely to have bridging fibrosis or cirrhosis (44% versus 21% [P = 0.05]) and stainable hepatic iron (50% versus 16% [P = 0.011]) compared with patients with other genotypes. Diabetes mellitus was the only independent predictor of advanced hepatic fibrosis (OR 4.37, 95% CI 1.41-13.54 [P = 0.010]) using multiple logistic regression analysis adjusting for age, sex, ethnicity, body mass index, and HFE genotype status.

CONCLUSION

The HFE C282Y heterozygous mutation is associated with advanced fibrosis among Caucasians with NASH. Additional studies are warranted to examine the possible mechanisms for this relationship.

Effects of iron overload in a rat nutritional model of non-alcoholic fatty liver disease

BACKGROUND/AIMS

This study sought to determine whether excess hepatic iron potentiates liver injury in the methionine choline-deficient (MCD) model of non-alcoholic fatty liver disease (NAFLD).

METHODS

Iron-loaded rats were fed either MCD or control diets [MCD diet plus choline bitartrate (2 g/kg) and DL-methionine (3 g/kg)] for 4 and 12 weeks, after which liver pathology, hepatic iron, triglyceride, lipid peroxidation products and hydroxyproline (HYP) levels and serum alanine aminotransferase (ALT) levels were evaluated.

RESULTS

Iron supplementation in MCD animals resulted in histologic evidence of hepatic iron overload at 4 and 12 weeks and a 14-fold increase in hepatic iron concentration at 12 weeks (P < 0.001). Iron supplementation in these animals was associated with increased lobular necroinflammation at 4 weeks (P < 0.02) and decreased hepatic steatosis (P < 0.01), hepatic triglyceride levels (P < 0.01), hepatic-conjugated dienes (CD; P < 0.02) and serum ALT levels (P < 0.002) at 12 weeks. Reduced hepatic steatosis (P < 0.005) and CD (P < 0.01) were apparent by 4 weeks. Iron supplementation was associated with a trend towards increased perivenular fibrosis not hepatic HYP content.

CONCLUSION

Hepatic iron overload in the MCD model of NAFLD is associated with decreased hepatic lipid, decreased early lipid peroxidation products, increased necroinflammation and a trend towards increased perivenular fibrosis.

Fructose-induced fatty liver disease: hepatic effects of blood pressure and plasma triglyceride reduction

The most known risk factor for nonalcoholic fatty liver disease (NAFLD) is the metabolic syndrome. In this study, we characterized changes in liver pathology, hepatic lipid composition, and hepatic iron concentration (HIC) occurring in rats given fructose-enriched diet (FED), with and without therapeutic maneuvers to reduce blood pressure and plasma triglycerides. Rats were given FED or standard rat chow for 5 weeks. Rats on FED were divided into 4 groups: receiving amlodipine (15 mg/kg per day), captopril (90 mg/kg per day), bezafibrate (10 mg/kg per day) in the last 2 weeks, or a control group that received FED only. FED rats had hepatic macrovesicular and microvesicular fat deposits develop, with increase in hepatic triglycerides (+198%) and hepatic cholesterol (+89%), but a decrease in hepatic phospholipids (-36%), hypertriglyceridemia (+223%), and hypertension (+15%), without increase in HIC. Amlodipine reduced blood pressure (-18%), plasma triglycerides (-12%), but there was no change in hepatic triglycerides and phospholipids concentrations. Captopril reduced blood pressure (-24%), plasma triglycerides (-36%), hepatic triglycerides (-51%), and hepatic macrovesicular fat (-51%), but increased HIC (+23%), with a borderline increase in hepatic fibrosis. Bezafibrate reduced plasma triglycerides (-49%), hepatic triglycerides (-78%), hepatic macrovesicular fat (-90%), and blood pressure (-11%). We conclude that FED rats can be a suitable model for human NAFLD. Drugs administered to treat various aspects of the metabolic syndrome could have hepatic effects. An increase in HIC in rats with NAFLD could be associated with increased hepatic fibrosis.