The role of iron in the pathophysiology and treatment of chronic hepatitis C

Mitochondrial dysfunction: A promising therapeutic target for liver diseases

The liver is an important metabolic and detoxification organ and hence demands a large amount of energy, which is mainly produced by the mitochondria. Liver tissues of patients with alcohol-related or non-alcohol-related liver diseases contain ultrastructural mitochondrial lesions, mitochondrial DNA damage, disturbed mitochondrial dynamics, and compromised ATP production. Overproduction of mitochondrial reactive oxygen species induces oxidative damage to mitochondrial proteins and mitochondrial DNA, decreases mitochondrial membrane potential, triggers hepatocyte inflammation, and promotes programmed cell death, all of which impair liver function. Mitochondrial DNA may be a potential novel non-invasive biomarker of the risk of progression to liver cirrhosis and hepatocellular carcinoma in patients infected with the hepatitis B virus. We herein present a review of the mechanisms of mitochondrial dysfunction in the development of acute liver injury and chronic liver diseases, such as hepatocellular carcinoma, viral hepatitis, drug-induced liver injury, alcoholic liver disease, and non-alcoholic fatty liver disease. This review also discusses mitochondrion-centric therapies for treating liver diseases.

Role of hepcidin upregulation and proteolytic cleavage of ferroportin 1 in hepatitis C virus-induced iron accumulation

Hepatitis C virus (HCV) is a pathogen characterized not only by its persistent infection leading to the development of cirrhosis and hepatocellular carcinoma (HCC), but also by metabolic disorders such as lipid and iron dysregulation. Elevated iron load is commonly observed in the livers of patients with chronic hepatitis C, and hepatic iron overload is a highly profibrogenic and carcinogenic factor that increases the risk of HCC. However, the underlying mechanisms of elevated iron accumulation in HCV-infected livers remain to be fully elucidated. Here, we observed iron accumulation in cells and liver tissues under HCV infection and in mice expressing viral proteins from recombinant adenoviruses. We established two molecular mechanisms that contribute to increased iron load in cells caused by HCV infection. One is the transcriptional induction of hepcidin, the key hormone for modulating iron homeostasis. The transcription factor cAMP-responsive element-binding protein hepatocyte specific (CREBH), which was activated by HCV infection, not only directly recognizes the hepcidin promoter but also induces bone morphogenetic protein 6 (BMP6) expression, resulting in an activated BMP-SMAD pathway that enhances hepcidin promoter activity. The other is post-translational regulation of the iron-exporting membrane protein ferroportin 1 (FPN1), which is cleaved between residues Cys284 and Ala285 in the intracytoplasmic loop region of the central portion mediated by HCV NS3-4A serine protease. We propose that host transcriptional activation triggered by endoplasmic reticulum stress and FPN1 cleavage by viral protease work in concert to impair iron efflux, leading to iron accumulation in HCV-infected cells.

Antimicrobial peptides: natural or synthetic defense peptides against HBV and HCV infections

According to the literature, treatment of HCV and HBV infections faces challenges due to problems such as the emergence of drug-resistant mutants, the high cost of treatment, and the side effects of current antiviral therapy. Antimicrobial peptides (AMPs), a group of small peptides, are a part of the immune system and are considered as an alternative treatment for microbial infections. These peptides are water-soluble with amphiphilic (hydrophilic and hydrophobic surfaces) characteristics. AMPs are produced by a wide range of organisms including both prokaryotic and eukaryotic cells. The antiviral mechanisms of AMPs include inhibiting virus entry, inhibiting intracellular virus replication, inhibiting intracellular viral packaging, and inducing immune responses. In addition, AMPs are a new generation of antiviral biomolecules that have very low toxicity for human host cells, particularly liver cell lines. AMPs can be considered as one of the most important strategies for developing new adjuvant drugs in the treatment of HBV and HCV infections. In the present study, several groups of AMPs (with a net positive charge) such as Human cathelicidin, Claudin-1, Defensins, Hepcidin, Lactoferrin, Casein, Plectasin, Micrococcin P1, Scorpion venom, and Synthetic peptides were reviewed with antiviral properties against HBV and HCV.

Iron Accumulation with Age alters Metabolic Pattern and Circadian Clock gene expression through the reduction of AMP-modulated Histone Methylation

Iron accumulates with age in mammals, and its possible implications in altering metabolic responses are not fully understood. Here we report that both high-iron diet and advanced age in mice consistently altered gene expression of many pathways, including those governing the oxidative stress response and the circadian clock. We used a metabolomic approach to reveal similarities between metabolic profiles and the daily oscillation of clock genes in old and iron-overloaded mouse livers. In addition, we show that phlebotomy decreased iron accumulation in old mice, partially restoring the metabolic patterns and amplitudes of the oscillatory expression of clock genes Per1 and Per2. We further identified that the transcriptional regulation of iron occurred through a reduction in AMP-modulated methylation of histone H3K9 in the Per1 and H3K4 in the Per2 promoters, respectively. Taken together, our results indicate that iron accumulation with age can affect metabolic patterns and the circadian clock.

Determination of mutations in iron regulating genes of beta thalassemia major patients of Khyber Pakhtunkhwa, Pakistan

Background

Hepcidin and hemochromatosis (HFE) are iron regulatory proteins that are encoded by HAMP and HFE genes. Mutation in either HAMP gene or HFE gene causes Hepcidin protein deficiency that can lead to iron overload in beta thalassemia patients. The aim of this research work was to study the presence of G71D mutation of HAMP gene and H63D mutation of HFE gene in beta thalassemia major and minor group to check the association of these mutations with serum ferritin level of beta thalassemia patients.

Methods

The study was conducted on 42 beta thalassemia major and 20 beta thalassemia minor samples along with 20 control samples. The genotyping of both mutations has done by ARM‐PCR technique with specific set of primers.

Results

Significant effect of G71D and H63D mutations was observed on serum ferritin level of thalassemia major group. The risk allele of HAMP G71D and HFE H63D was found with high frequency (48% and 49%, respectively) in beta thalassemia major than in control group. High genotypic frequency of HAMP and HFE gene mutation gene mutation was observed in beta thalassemia major than beta thalassemia minor and control group (7% and 9%, respectively).

Conclusion

It can be concluded that both HAMP and HFE gene mutations show high frequency in beta thalassemia major patients and mean significant association between mutations and high serum ferritin level of beta thalassemia major patients but the nonsignificant results of Odd ratios showed that both mutations do not act as major risk factor in beta thalassemia major.

Prevalence and characteristics of anti-HCV positivity and chronic hepatitis C virus infection in HFE p.C282Y homozygotes

INTRODUCTION AND AIM

Observations of hepatitis C virus (HCV) infection in adults with hemochromatosis are limited.

MATERIALS AND METHODS

We determined associations of serum ferritin (SF) with anti-HCV in non-Hispanic white North American adults in a post-screening examination. Cases included p.C282Y homozygotes (regardless of screening transferrin saturation (TS) and SF) and participants (regardless of HFE genotype) with high screening TS/SF. Controls included participants without p.C282Y or p.H63D who had normal screening TS/SF. Participants with elevated alanine aminotransferase underwent anti-HCV testing. We determined prevalence of chronic HCV infection in consecutive Alabama and Ontario referred adults with HFE p.C282Y homozygosity.

RESULTS

In post-screening participants, anti-HCV prevalence was 0.3% [95% CI: 0.02, 2.2] in 294 p.C282Y homozygotes, 9.5% [7.2, 12.3] in 560 Cases without p.C282Y homozygosity, and 0.7% [0.2, 2.3] in 403 Controls. Anti-HCV was detected in 7.2% of 745 participants with and 0.8% of 512 participants without elevated SF (odds ratio 9.9 [3.6, 27.6]; p<0.0001). Chronic HCV infection prevalence in 961 referred patients was 1.0% (10/961) [95% confidence interval (CI): 0.5, 2.0]. Ten patients with chronic HCV infection had median age 45y (range 29-67) and median SF 1163μg/L (range 303-2001). Five of eight (62.5%) patients had biopsy-proven cirrhosis.

CONCLUSIONS

Odds ratio of anti-HCV was increased in post-screening participants with elevated SF. Prevalence of anti-HCV in post-screening participants with HFE p.C282Y homozygosity and chronic HCV infection in referred adults with HFE p.C282Y homozygosity in North America is similar to that of Control participants with HFE wt/wt and normal screening TS/SF.

Review article: iron disturbances in chronic liver diseases other than haemochromatosis - pathogenic, prognostic, and therapeutic implications

BACKGROUND

Disturbances in iron regulation have been described in diverse chronic liver diseases other than hereditary haemochromatosis, and iron toxicity may worsen liver injury and outcome.

AIMS

To describe manifestations and consequences of iron dysregulation in chronic liver diseases apart from hereditary haemochromatosis and to encourage investigations that clarify pathogenic mechanisms, define risk thresholds for iron toxicity, and direct management METHODS: English abstracts were identified in PubMed by multiple search terms. Full length articles were selected for review, and secondary and tertiary bibliographies were developed.

RESULTS

Hyperferritinemia is present in 4%-65% of patients with non-alcoholic fatty liver disease, autoimmune hepatitis, chronic viral hepatitis, or alcoholic liver disease, and hepatic iron content is increased in 11%-52%. Heterozygosity for the C282Y mutation is present in 17%-48%, but this has not uniformly distinguished patients with adverse outcomes. An inappropriately low serum hepcidin level has characterised most chronic liver diseases with the exception of non-alcoholic fatty liver disease, and the finding has been associated mainly with suppression of transcriptional activity of the hepcidin gene. Iron overload has been associated with oxidative stress, advanced fibrosis and decreased survival, and promising therapies beyond phlebotomy and oral iron chelation have included hepcidin agonists.

CONCLUSIONS

Iron dysregulation is common in chronic liver diseases other than hereditary haemochromatosis, and has been associated with liver toxicity and poor prognosis. Further evaluation of iron overload as a co-morbid factor should identify the key pathogenic disturbances, establish the risk threshold for iron toxicity, and promote molecular interventions.

Elevated serum ferritin level associated with hepatic steatosis and fibrosis in hepatitis C virus-infected patients

BACKGROUND

Serum ferritin is an indicator of iron accumulation in a human body, and it is frequently elevated in patients with systemic inflammatory state in chronic hepatitis C (CHC). Iron accumulation is associated with hepatic fibrosis, steatosis, and unfavorable outcome in CHC patients. We studied the status of elevated serum ferritin level and its association with the liver fibrosis or steatosis in Taiwanese CHC patients.

METHODS

Seven hundred and thirty-eight Taiwanese CHC patients were consecutively included in this study. Laboratory analysis, four indexes of fibrosis (FIB4), histological assessment of fibrosis, and steatosis were assessed by appropriate elevation of serum ferritin level.

RESULTS

Three hundred and one patients (40.8%) had elevated serum ferritin level (sex-specific threshold >1.5 × upper limit of normal). Serum iron level (odds ratio [OR], 1.02; 95% CI, 1.01%-1.03%, p < 0.001), female gender (OR, 1.49; 95% CI, 1.07%-2.08%, p = 0.018), serum gamma-glutamyl transferase level (OR, 1.007; 95% CI, 1.003%-1.01%, p < 0.001), steatosis grade (OR, 1.56; 95% CI, 1.13%-2.16%, p = 0.006), and FIB4 ≥3.25 (OR, 1.63; 95% CI, 1.18%-2.27%, p = 0.003) indexes were associated with high serum ferritin level by multivariate logistic regression analysis. Patients with steatosis (>5%) were associated with older age (OR, 1.01; 95% CI, 1.00%-1.03%, p = 0.015), body mass index (OR, 1.10; 95% CI, 1.05%-1.15%, p < 0.001), and elevated serum ferritin level (OR, 1.001; 95% CI, 1.00%-1.001%, p = 0.024) by multivariate logistic regression analysis. Serum ferritin level also associated with high FIB4 (≥3.25) (OR, 1.001; 95% CI, 1.001%-1.002%, p = 0.010) when multivariate model adjusted together with advanced liver fibrosis by biopsy.

CONCLUSION

Elevated serum ferritin level was noted in 40.8% of Taiwanese CHC patients, and the serum ferritin level was associated with liver steatosis and high FIB4.

Biomarkers of Nutrition for Development (BOND)-Iron Review

This is the fifth in the series of reviews developed as part of the Biomarkers of Nutrition for Development (BOND) program. The BOND Iron Expert Panel (I-EP) reviewed the extant knowledge regarding iron biology, public health implications, and the relative usefulness of currently available biomarkers of iron status from deficiency to overload. Approaches to assessing intake, including bioavailability, are also covered. The report also covers technical and laboratory considerations for the use of available biomarkers of iron status, and concludes with a description of research priorities along with a brief discussion of new biomarkers with potential for use across the spectrum of activities related to the study of iron in human health.The I-EP concluded that current iron biomarkers are reliable for accurately assessing many aspects of iron nutrition. However, a clear distinction is made between the relative strengths of biomarkers to assess hematological consequences of iron deficiency versus other putative functional outcomes, particularly the relationship between maternal and fetal iron status during pregnancy, birth outcomes, and infant cognitive, motor and emotional development. The I-EP also highlighted the importance of considering the confounding effects of inflammation and infection on the interpretation of iron biomarker results, as well as the impact of life stage. Finally, alternative approaches to the evaluation of the risk for nutritional iron overload at the population level are presented, because the currently designated upper limits for the biomarker generally employed (serum ferritin) may not differentiate between true iron overload and the effects of subclinical inflammation.

Low hepcidin in liver fibrosis and cirrhosis; a tale of progressive disorder and a case for a new biochemical marker

Liver fibrosis is a precursor of liver cirrhosis, which is associated with increased mortality. Though liver biopsy remains the gold standard for the diagnosis of fibrosis, noninvasive biochemical methods are cost-effective, practical and are not linked with major risks of complications. In this respect, serum hepcidin, has emerged as a new marker of fibrosis and cirrhosis. In this review the discussion uncovers molecular links between hepcidin disturbance and liver fibrosis/cirrhosis. The discussion also expands on clinical studies that suggest that hepcidin can potentially be used as a biochemical parameter of fibrosis/cirrhosis and target of therapeutic strategies to treat liver diseases. The debatable issues such as the complicated nature of hepcidin disturbance in non-alcoholic liver disease, serum levels of hepcidin in acute hepatitis C virus infection, cause of hepcidin disturbance in autoimmune hepatitis and hepatic insulin resistance are discussed, with potential solutions unveiled in order to be studied by future research.

Improvement of chronic hepatitis B by iron chelation therapy in a patient with iron overload: A case report

RATIONALE

This report describes seroconversion of hepatitis B surface antigen (HBsAg) in a patient with marked iron overload caused by chronic hepatitis B (CHB) after receiving iron chelation therapy and discusses the role of iron chelation therapy in CHB.

PATIENT CONCERNS

Increased serum ferritin level for 2 months.

DIAGNOSIS

Secondary iron overload and CHB.

INTERVENTION

To relieve iron load of the body, the patient underwent regular phlebotomy therapy and deferoxamine (DFO) therapy. During the therapy, serum ferritin and hepatitis B virus (HBV) were monitored and the iron concentration of the liver and heart were followed by T2* of magnetic resonance imaging (MRI) scan.

OUTCOMES

Serum ferritin gradually decreased. Approximately 1 year after the therapy, HBsAg turned persistently negative.

LESSONS

Iron chelation therapy may attenuate HBV infection.

HFE mRNA expression is responsive to intracellular and extracellular iron loading: short communication

In liver hepatocytes, the HFE gene regulates cellular and systemic iron homeostasis by modulating cellular iron-uptake and producing the iron-hormone hepcidin in response to systemic iron elevation. However, the mechanism of iron-sensing in hepatocytes remain enigmatic. Therefore, to study the effect of iron on HFE and hepcidin (HAMP) expressions under distinct extracellular and intracellular iron-loading, we examined the effect of holotransferrin treatment (1, 2, 5 and 8 g/L for 6 h) on intracellular iron levels, and mRNA expressions of HFE and HAMP in wild-type HepG2 and previously characterized iron-loaded recombinant-TfR1 HepG2 cells. Gene expression was analyzed by real-time PCR and intracellular iron was measured by ferrozine assay. Data showed that in the wild-type cells, where intracellular iron content remained unchanged, HFE expression remained unaltered at low holotransferrin treatments but was upregulated upon 5 g/L (p < 0.04) and 8 g/L (p = 0.05) treatments. HAMP expression showed alternating elevations and increased upon 1 g/L (p < 0.05) and 5 g/L (p < 0.05). However, in the recombinant cells that showed higher intracellular iron levels than wild-type cells, HFE and HAMP expressions were elevated only at low 1 g/L treatment (p < 0.03) and were repressed at 2 g/L treatment (p < 0.03). Under holotransferrin-untreated conditions, the iron-loaded recombinant cells showed higher expressions of HFE (p < 0.03) and HAMP (p = 0.05) than wild-type cells. HFE mRNA was independently elevated by extracellular and intracellular iron-excess. Thus, it may be involved in sensing both, extracellular and intracellular iron. Repression of HAMP expression under simultaneous intracellular and extracellular iron-loading resembles non-hereditary iron-excess pathologies.

Relationship between Hepatitis C Virus Infection and Iron Overload

Objective:

The aim of this study was to summarize the interactions between hepatitis C virus (HCV) infection and iron overload, and to understand the mechanisms of iron overload in chronic hepatitis C (CHC) and the role iron plays in HCV life cycle.

Data Sources:

This review was based on data in articles published in the PubMed databases up to January 28, 2017, with the keywords “hepatitis C virus”, “iron overload”, “iron metabolism”, “hepcidin”, “translation”, and “replication”.

Study Selection:

Articles related to iron metabolism, iron overload in patients with CHC, or the effects of iron on HCV life cycle were selected for the review.

Results:

Iron overload is common in patients with CHC. The mechanisms involve decreased hepcidin levels caused by HCV through signal transducer and activator of transcription 3, mitogen-activated protein kinase, or bone morphogenetic protein/SMAD signaling pathways, and the altered expression of other iron-metabolism-related genes. Some studies found that iron increases HCV replication, while other studies found the opposite result. Most of the studies suggest the positive role of iron on HCV translation, the mechanisms of which involve increased expression levels of factors associated with HCV internal ribosome entry site-dependent translation, such as eukaryotic initiation factor 3 and La protein.

Conclusion:

The growing literature demonstrates that CHC leads to iron overload, and iron affects the HCV life cycle in turn. Further research should be conducted to clarify the mechanism involved in the complicated interaction between iron and HCV.

Impact of iatrogenic iron overload on the course of hepatitis C in the dialysis population: A plea for caution

About 2.5% of the world population, corresponding to about 177 million individuals, are infected by hepatitis C virus (HCV), a small, single-stranded RNA virus. The prevalence of HCV infection among dialysis patients in Japan, Europe, and North America during the 2012 to 2015 period was found to be 8.7% in the DOPPS study. Nosocomial HCV spread in hemodialysis facilities still occurs. Increased hepatic tissue iron has been shown to play a deleterious role in the course of hepatitis C, favor development of fibrosis and cirrhosis and possibly increase the risk of liver cancer in the general population. Regular loss of blood in the hemodialysis circuit, in routine blood sampling for laboratory tests (for uremia monitoring), and in gut due to uremic enteropathy, invariably results in iron deficiency for which patients are commonly treated with intravenous (IV) iron preparations. Data on the effects of IV iron in hemodialysis patients with hepatitis C are limited (2 studies) and strongly suggest that parenteral iron may contribute to hepatocellular injury. Iatrogenic iron overload is extremely prevalent among hemodialysis population worldwide. Iron overload and toxicity has emerged as one of the most controversial topic in the management of anemia in dialysis patients. Given the known impact of iron in promoting growth and virulence of HCV and the associated liver disease, it is necessary to use iron therapy cautiously and closely monitor plasma markers of iron metabolism and liver iron stores non-invasively by means of MRI to avoid iron overload in this vulnerable population.

Hepcidin inhibits Smad3 phosphorylation in hepatic stellate cells by impeding ferroportin-mediated regulation of Akt

Hepatic stellate cell (HSC) activation on liver injury facilitates fibrosis. Hepatokines affecting HSCs are largely unknown. Here we show that hepcidin inhibits HSC activation and ameliorates liver fibrosis. We observe that hepcidin levels are inversely correlated with exacerbation of fibrosis in patients, and also confirm the relationship in animal models. Adenoviral delivery of hepcidin to mice attenuates liver fibrosis induced by CCl₄ treatment or bile duct ligation. In cell-based assays, either hepcidin from hepatocytes or exogenous hepcidin suppresses HSC activation by inhibiting TGFβ1-mediated Smad3 phosphorylation via Akt. In activated HSCs, ferroportin is upregulated, which can be prevented by hepcidin treatment. Similarly, ferroportin knockdown in HSCs prohibits TGFβ1-inducible Smad3 phosphorylation and increases Akt phosphorylation, whereas ferroportin over-expression has the opposite effect. HSC-specific ferroportin deletion also ameliorates liver fibrosis. In summary, hepcidin suppresses liver fibrosis by impeding TGFβ1-induced Smad3 phosphorylation in HSCs, which depends on Akt activated by a deficiency of ferroportin.

The peptide hormone hepcidin is released from hepatocytes and regulates iron homoeostasis. Here, the authors show that hepcidin also regulates the activation of hepatic stellate cells (HSCs) in mouse models of liver fibrosis by reducing ferroportin expression and inhibiting the HSC response to TGFβ.

Iron depletion enhances the effect of sorafenib in hepatocarcinoma

ABSTACT Human hepatocellular carcinoma (HCC) is known to have a poor prognosis. Sorafenib, a molecular targeted drug, is most commonly used for HCC treatment. However, its effect on HCC is limited in clinical use and therefore new strategies regarding sorafenib treatment are required. Iron overload is known to be associated with progression of chronic hepatitis and increased risk of HCC. We previously reported that iron depletion inhibited cancer cell proliferation and conversely induced angiogenesis. Indeed iron depletion therapy including iron chelator needs to be combined with anti-angiogenic drug for its anti-cancer effect. Since sorafenib has an anti-angiogenic effect by its inhibitory targeting VEGFR, we hypothesized that sorafenib could complement the anti-cancer effect of iron depletion. We retrospectively analyzed the relationship between the efficacy of sorafenib and serum iron-related markers in clinical HCC patients. In clinical cases, overall survival was prolonged in total iron binding capacity (TIBC) high- and ferritin low-patients. This result suggested that the low iron-pooled patients, who could have a potential of more angiogenic properties in/around HCC tumors, could be adequate for sorafenib treatment. We determined the effect of sorafenib (Nexavar®) and/or deferasirox (EXJADE®) on cancer cell viability, and on cell signaling of human hepatocarcinoma HepG2 and HLE cells. Both iron depletion by deferasirox and sorafenib revealed insufficient cytotoxic effect by each monotherapy, however, on the basis of increased angiogenesis by iron depletion, the addition of deferasirox enhanced anti-proliferative effect of sorafenib. Deferasirox was confirmed to increase vascular endothelial growth factor (VEGF) secretion into cellular supernatants by ELISA analysis. In in vivo study sorafenib combined with deferasirox also enhanced sorafenib-induced apoptosis. These results suggested that sorafenib combined with deferasirox could be a novel combination chemotherapy for HCC.

Dysregulated iron homeostasis is strongly associated with multiorgan failure and early mortality in acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) is an ailment with high incidence of multiorgan failure (MOF) and consequent mortality. Dysregulated iron homeostasis and macrophage dysfunction are linked to increased incidence of MOF. We investigated whether a panel of circulating iron-regulating proteins are associated with development of MOF and can predict 15- or 30-day mortality in ACLF patients. One hundred twenty patients with ACLF, 20 patients with compensated cirrhosis, and 20 healthy controls were studied. Relative protein expression profiling was performed in the derivative cohort and confirmed in the validation cohort. A panel of iron regulators and indices were determined. Multiparametric flow cytometry for quantitation of labile iron pool (LIP) was performed. Validation studies confirmed lower serum transferrin (Tf) and ceruloplasmin levels in ACLF and ACLF-MOF, compared to patients with cirrhosis and controls (P < 0.01). Serum iron and ferritin levels were markedly elevated (P < 0.001; P < 0.05) and hepcidin levels were lower (P < 0.001) in ACLF patients with MOF than those without and other groups (P < 0.001). Percentage Tf saturation (%SAT) was higher in ACLF-MOF (39.2%; P < 0.001) and correlated with poor outcome (hazard ratio: 6.970; P < 0.01). Intracellular LIP indices were significantly elevated in the subsets of circulating macrophages in ACLF-MOF, compared to other groups (P < 0.01). Whereas expression of iron-regulatory genes was markedly down-regulated, genes related to endoplasmic reticulum stress, apoptosis, and inflammation were up-regulated in ACLF patients, compared to patients with cirrhosis. Severe dysregulation of autophagy mechanisms was also observed in the former.

CONCLUSIONS

Iron metabolism and transport are severely deranged in ACLF patients and more so in those with MOF. %SAT, circulating hepcidin, and LIP in macrophages correlate with disease severity and %SAT could be used for early prognostication in ACLF patients.

Hepcidin/ferroportin expression levels involve efficacy of pegylated-interferon plus ribavirin in hepatitis C virus-infected liver

AIM: To investigate the relationship between the iron-metabolism-related gene expression profiles and efficacy of antiviral therapy in chronic hepatitis C patients.

METHODS: The hepatic expression profile of iron-metabolism-related genes was analyzed and its association with virological response to pegylated-interferon plus ribavirin combination therapy was evaluated. A hundred patients with chronic hepatitis C (genotype1b, n = 50; genotype 2, n = 50) were enrolled and retrospectively analyzed. Liver biopsy samples were subjected to quantitative polymerase chain reaction for iron-metabolism-related genes and protein expression (Western blotting analysis) for ferroportin. As a control, normal liver tissue was obtained from 18 living donors of liver transplantation. Serum hepcidin level was measured by sensitive liquid chromatography/electrospray ionization tandem mass spectrometry.

RESULTS: Iron overload is associated with liver damage by increasing oxidative stress and hepatitis C virus (HCV) is reported to induce iron accumulation in hepatocytes in vivo. Conversely, iron administration suppresses HCV replication in vitro. Therefore, the association between HCV infection and iron metabolism remains unclear. Compared with controls, patients had significantly higher gene expression for transferrin, iron-regulatory proteins 1 and 2, divalent metal transporter 1, and ferroportin, but similar for transferrin receptors 1 and 2, and hepcidin. When the expression profiles were compared between sustained virological response (SVR) and non-SVR patients, the former showed significantly lower transcription and protein expression of hepcidin and ferroportin. Expression of hepcidin-regulating genes, BMPR1, BMPR2, and hemojuvelin, was significantly increased, whereas BMP2 was decreased in HCV-infected liver. BMPR2 and hemojuvelin expression was significantly lower in the SVR than non-SVR group. HCV infection affects the expression of iron-metabolism-related genes, leading to iron accumulation in hepatocytes.

CONCLUSION: Decreased expression of hepcidin and ferroportin in SVR patients indicates the importance of hepatocytic iron retention for viral response during pegylated-interferon plus ribavirin treatment.

Potential roles of BMP9 in liver fibrosis

Liver fibrosis is a common phenomenon that is associated with several pathologies and is characterized by excessive extracellular matrix deposition that leads to progressive liver dysfunction. Bone morphogenetic protein 9 (BMP9) is the most recently discovered member of the BMP family. BMP9 bound with high affinity to activin receptor-like kinase 1 (ALK1) and endoglin in non-parenchymal liver cells. In addition, BMP9 activated Smad1/Smad5/Smad8 and induced the expression of the target genes inhibitor of differentiation 1 (Id1), hepcidin, Snail and the co-receptor endoglin in liver cells. Although the role of BMP9 in liver fibrosis is currently poorly understood, the presence of BMP9-activated proteins and its target genes have been reported to be associated with liver fibrosis development. This review summarizes the indirect connection between BMP9 and liver fibrosis, with a focus on the BMP9 signaling pathway members ALK1, endoglin, Id1, hepcidin and Snail. The observations on the role of BMP9 in regulating liver fibrosis may help in understanding the pathology mechanisms of liver disease. Furthermore, BMP9 could be served as a potent biomarker and the target of potential therapeutic drugs to treat hepatocytes fibrosis.

Duodenal ferroportin is up-regulated in patients with chronic hepatitis C

Hepatitis C virus (HCV) infection is a leading cause of liver-related mortality. Chronic hepatitis C (CHC) is frequently associated with disturbances in iron homeostasis, with serum iron and hepatic iron stores being elevated. Accumulating evidence indicates that chronic HCV infection suppresses expression of hepatic hepcidin, a key mediator of iron homeostasis, leading to iron overload conditions. Since hepcidin mediates degradation of ferroportin, a basolateral transporter involved in the release of iron from cells, diminished hepcidin expression probably leads to up-regulation of ferroportin-1 (Fpn1) in patients with CHC. In this study, we determined the protein levels of duodenal Fpn1, and found that its expression was significantly up-regulated in patients with CHC. The expression of duodenal Fpn1 is negatively correlated with mRNA levels of hepcidin, and positively correlated with serum iron parameters. Although iron is a critical factor for growth of a variety of pathogenic bacteria, our results suggest that iron overload in blood does not increase the infection rate of bacteria in patients with CHC.

Iron homeostasis and its regulators over the course of chronic hepatitis C

ABSTRACT: 

Chronic infection with HCV has been diagnosed in approximately 170 million people worldwide. It is an important cause of chronic, progressive liver fibrosis. Late consequences of chronic HCV infection, including liver cirrhosis and hepatocellular carcinoma, have become the major indications for liver transplantation in developed countries. Particular attention is being paid to iron accumulation in chronic hepatitis C and its relation to the current antiviral therapy's efficacy and safety, risk of exacerbation of oxidative stress, development of metabolic disorders and hepatocarcinogenesis. HCV infection disrupts the synthesis of hepcidin, which regulates extracellular iron content. This article discusses the impact of iron on HCV multiplication and the involvement of impaired iron homeostasis in chronic hepatitis C in terms of the pathogenesis of insulin resistance, fatty liver and hepatocarcinogenesis.

Hepatic iron overload and hepatocellular carcinoma

In recent years it has become increasingly evident that excess body iron may be complicated by the supervention of hepatocellular carcinoma (HCC). Hereditary hemochromatosis (HH) was the first condition in which hepatic iron overload was shown to predispose to the development of HCC. The inherited predisposition to excessive absorption of dietary iron in HH is almost always the result of homozygosity of the C282Y mutation of the HFE gene, which causes inappropriately low secretion of hepcidin. HCC develops in 8-10% of patients with HH and is responsible for approximately 45% of deaths in the HCC patients. Cirrhosis is almost always present when HCC is diagnosed. Dietary iron overload is a condition which occurs in rural-dwelling Black Africans in southern Africa as a result of the consumption, over time, of large volumes of alcohol home-brewed in iron containers and having, as a consequence, a high iron content. Iron loading of the liver results and may be complicated by malignant transformation of the liver (relative risk of approximately 10.0). Accompanying cirrhosis does occur but is less common than that in HH. The development of HCC as a consequence of increased dietary iron, and the fact that it may develop in the absence of cirrhosis, has been confirmed in an animal model. Drinking water with a high iron content might contribute to the high incidence of HCC in parts of Taiwan. The metabolic syndrome [obesity, insulin resistance type 2 (or diabetes mellitus type 2), non-alcoholic fatty liver or non-alcoholic steatohepatitis] has in recent years become a major public health problem in some resource-rich countries. A link between excess body iron and insulin resistance or the metabolic syndrome has become apparent. The metabolic syndrome may be complicated by the supervention of HCC, and recent evidence suggests that increased body iron may contribute to this complication.