Insulin resistance, steatosis and hepatitis C virus

Metabolic complications of hepatitis C virus infection

Hepatitis C virus (HCV) infection is a systemic disease that is implicated in multiple extrahepatic organ dysfunction contributing to its protean manifestations. HCV is associated with diverse extrahepatic disorders including atherosclerosis, glucose and lipid metabolic disturbances, alterations in the iron metabolic pathways, and lymphoproliferative diseases over and above the traditional liver manifestations of cirrhosis and hepatocellular carcinoma. The orchestration between HCV major proteins and the liver-muscle-adipose axis, poses a major burden on the global health of human body organs, if not adequately addressed. The close and inseparable associations between chronic HCV infection, metabolic disease, and cardiovascular disorders are specifically important considering the increasing prevalence of obesity and metabolic syndrome, and their economic burden to patients, the healthcare systems, and society. Cellular and molecular mechanisms governing the interplay of these organs and tissues in health and disease are therefore of significant interest. The coexistence of metabolic disorders and chronic hepatitis C infection also enhances the progression to liver fibrosis and hepatocellular carcinoma. The presence of metabolic disorders is believed to influence the chronicity and virulence of HCV leading to liver disease progression. This comprehensive review highlights current knowledge on the metabolic manifestations of hepatitis C and the potential pathways in which these metabolic changes can influence the natural history of the disease.

Beneficial effects of DAAs on cardiac function and structure in hepatitis C patients with low-moderate liver fibrosis

Hepatitis C virus (HCV)-related chronic infection has been associated with a higher incidence of cardiovascular diseases. An altered morphology and function of both left and right heart have been described in HCV patients; however, the causality of the association is still debated. Ninety-eight nonobese and nondiabetic HCV patients (59.5 ± 12.0 years; males 52%) with Fibroscan-Transient Elastography assessed low-moderate liver fibrosis that achieved sustained viral response at 12 and 24 weeks after DAAs (direct-acting antivirals) participated. 56 were matched with 52 control subjects for age, sex and cardiovascular risk factors at baseline. A trans-thoracic echocardiography was performed in each subject at baseline (T0) and repeated in all HCV patients after eradication (6 months later eligibility, T1). TNF-α and IL-10 were measured at baseline and at T1. A concentric remodelling of the left heart in HCV participants was identified, whereas tricuspidal annular plane systolic excursion, right indexed atrial volume, right basal ventricular diameter, inferior vena cava diameter and pulmonary arterial pressure were higher in HCV participants compared to matched controls. After virus eradication, left indexed atrial volume and all right cardiac chambers measures were lower than baseline. A significant reduction of TNF-α was shown at T1, while IL-10 did not change. This study shows a concentric remodelling of the left ventricle and structural modifications in the right sections in HCV patients compared to controls. Virus eradication with DAAs was associated with a reduction of the main right atrioventricular parameters indicating a direct involvement of the HCV in cardiac changes.

HCV Extrahepatic Manifestations

Hepatitis C virus (HCV) has been shown to affect many tissues other than liver. However, of the many extrahepatic manifestations (EMs) that have been associated with HCV, including cryoglobulinemia, lymphoma, insulin resistance, type 2 diabetes and neurological disorders, only a few have been shown to be directly related to HCV infection of extrahepatic tissues. HCV-triggered immune-mediated mechanisms account for most of the EMs. It is estimated that up to 74% of patients with chronic hepatitis C can develop at least one EM. All HCV patients with EMs should be considered for antiviral therapy, although not all will resolve with sustained virological response.

Hepatitis C Virus Infection in the Older Patient

Hepatitis C virus (HCV) is the most common blood-borne infection in the United States and is of concern in older adults. HCV infection is associated with not only hepatic but also extrahepatic comorbidities common to the aging patient including diabetes, kidney and cardiovascular diseases, and neurocognitive impairment. The effect of direct-acting antiviral agents to treat HCV on these outcomes is limited. This article summarizes the literature regarding the epidemiology and natural history of HCV infection; the impact of age on clinical outcomes in HCV-infected persons; and current knowledge regarding safety and efficacy of HCV treatment regimens in the older patient.

Hepatitis C and Its Metabolic Complications in Kidney Disease

INTRODUCTION

Evidence has been accumulated during the last decade showing that HCV infection plays an important activity at hepatic and extra-hepatic level. Chronic HCV is associated with a large spectrum of extra-hepatic manifestations including lympho-proliferative diseases and metabolic abnormalities (such as insulin resistance and fatty liver disease).

MATERIAL AND METHODS

We have performed an extensive review of the medical literature regarding the increased risk of cardiovascular and kidney disease that has been observed in various groups of HCV-infected patients. The potential link between such increased risk and the metabolic consequences of chronic HCV infection has been explored.

RESULTS

According to a systematic review with a meta-analysis of longitudinal studies (n = 9 clinical observational studies; n = 1,947,034 unique patients), we found a strong relationship between positive anti-HCV serologic status and increased incidence of chronic kidney disease in the adult general population, the summary estimate for adjusted hazard ratio was 1.43 (95% confidence intervals, 1.23; 1.63, P = 0.0001) (random-effects model) in anti-HCV positive patients. In another meta-analysis of clinical observational studies (n = 145,608 unique patients on long term dialysis; n = 14 observational studies), anti-HCV sero-positive status was an independent and significant risk factor for death in patients on maintenance dialysis. The summary estimate for adjusted relative risk (all-cause mortality) was 1.35 with a 95% confidence interval (CI) of 1.25; 1.47 (P < 0.01) in anti-HCV positive patients on maintenance dialysis. An updated and stratified analysis (n = 4 studies, n = 91,916 patients on maintenance dialysis) resulted in an adjusted HR for cardiovascular mortality among anti-HCV positive patients of 1.21 (95% CI, 1.06; 1.39) (P < 0.01); the homogeneity assumption was not rejected. The mechanisms underlying such relationships remain unclear; it has been suggested that HCV promotes atherogenesis through direct and indirect mechanisms.

CONCLUSIONS

Clinical trials are under way to assess whether the clearance of HCV RNA from serum by direct-acting antiviral drugs reduces all cause or disease-specific (cardiovascular) mortality among patients on maintenance dialysis.

The prevalence of steatohepatitis in chronic hepatitis B patients and its impact on disease severity and treatment response

BACKGROUND & AIMS

The clinical significance of steatohepatitis in chronic hepatitis B remains unclear. This study aimed to determine the prevalence and risk factors for steatohepatitis in chronic hepatitis B, and to determine its correlation with liver fibrosis and response to antiviral therapy.

METHODS

Liver histopathology of 256 consecutive chronic hepatitis B patients with serum hepatitis B virus DNA >2000 IU/mL were analysed with clinical and laboratory characteristics. Virological and biochemical responses were prospectively assessed in the 112 patients treated with antiviral monotherapy.

RESULTS

Hepatic steatosis was observed in 38% of the entire cohort, and steatohepatitis was diagnosed in 18% of patients with hepatic steatosis according to Brunt's classification. The presence of steatohepatitis was associated with overweight/obese (odds ratio, 5.99; 95% CI, 1.32-27.2) and hypertriglyceridaemia (odds ratio, 2.95; 95% CI, 1.07-8.15). None of the viral characteristics including HBeAg status, genotypes and viraemia levels was associated with the presence of steatohepatitis. Steatohepatitis was an independent predictor of significant fibrosis (odds ratio, 10.0; 95% CI, 2.08-48.5) and advanced fibrosis (odds ratio, 3.45; 95% CI, 1.11-10.7) after adjusting for viraemia levels and features of the metabolic syndrome. The rates of suppression of serum hepatitis B virus DNA <20 IU/mL combined with aminotransferase normalization at week 48 of antiviral therapy were not different between the steatohepatitis and non-steatohepatitis groups (43% vs 53%; P=.475).

CONCLUSIONS

Steatohepatitis is not uncommon in chronic hepatitis B patients. It is associated with metabolic syndrome but not viral factor. This study demonstrates that steatohepatitis is related to the severity of liver fibrosis but it does not affect response to antiviral therapy.

Alterations in serum levels of fetuin A and selenoprotein P in chronic hepatitis C patients with concomitant type 2 diabetes: A case-control study

BACKGROUND

Insulin resistance (IR) and type 2 diabetes mellitus (T2DM) are serious extrahepatic manifestations of chronic hepatitis C virus (HCV) infection. However, the mechanism underlying the IR in chronic HCV is obscure. Hepatokines are group of liver-derived protein, which affect the glucose and lipid metabolism in several tissues. Fetuin A (also known as human α2-HS-glycoprotein) is one of the hepatokines, which was recognized as a natural inhibitor of the insulin receptor tyrosine kinase in liver and skeletal muscle. Additionally, selenoprotein P has emerged as an important hepatokine, which primarily acts as selenium transporter and has been reported to be implicated in glucose homeostasis in human.

OBJECTIVE

The aim of the current case-control study was to investigate the serum levels of both fetuin A and selenoprotein P in chronic hepatitis C patients with or without T2DM and to correlate their levels with other biochemical parameters of insulin resistance.

MAIN FINDINGS

Our results showed that, serum fetuin A levels increased significantly in HCV patients compared with controls (P<0.01) and surplus increase was found in HCV with concomitant T2DM (P>0.001). However, selenoprotein P levels significantly elevated only in patients with both HCV and T2DM (P<0.05) compared with the healthy subjects. Both fetuin A and selenoprotein P were positively correlated with fasting blood glucose. Yet, only fetuin A was significantly correlated to the HOMA-IR (r=0.28; P=0.03).

CONCLUSIONS

These results indicate crucial roles played by fetuin A and selenoprotein P in the IR caused by HCV and that both hepatokines may be targets for the development of therapies to treat or inhibit insulin resistance associated to HCV. However, further studies on large scale should be conducted to confirm our findings.

Hepatitis C virus as a systemic disease: reaching beyond the liver

Chronic hepatitis C (CHC) is associated with multiple extrahepatic manifestations that may impact infected patients. The mechanisms through which these develop include those which are immunological, in which the chronic persistence of virus leads to the circulation of immune complexes (mixed cryoglobulinemia) and other autoimmune phenomena, and those which are virological and related to the extrahepatic tropism of the virus to other tissues. It is estimated that 40-74 % of patients with CHC may develop at least one extrahepatic manifestation during the course of the disease. Extrahepatic syndromes may represent the first signal of hepatitis C infection in some patients. CHC is associated with a four-fold increased risk of insulin resistance and type 2 diabetes mellitus; with cardiovascular disease in 17-37 % of patients; and with increased risk for cerebrovascular deaths, with a biological gradient of cerebrovascular mortality correlating with an increasing serum viral load. CHC is also associated with lymphoproliferative disorders, particularly non-Hodgkin B-cell lymphoma. The kidney is involved in 35-60 % of patients with CHC-associated mixed cryoglobulinemia. The prevalent type of glomerulonephritis associated with mixed cryoglobulinemia is membranoproliferative glomerulonephritis. In 30 % of cases, renal involvement begins with a nephritis syndrome and acute renal failure, while in 55 % there is only mild hematuria, microalbuminuria, proteinuria and renal insufficiency. CHC is also associated with cognitive impairment, especially in memory and concentration. Thus, extrahepatic CHC manifestations involve multiple organ systems outside the liver linked to a variety of comorbidities which may lead to significantly increased mortality from non-liver-related events.

Metabolic Manifestations and Complications Associated With Chronic Hepatitis C Virus Infection

Chronic hepatitis C virus (HCV) infection is associated with many extrahepatic manifestations that contribute to morbidity and mortality. It is especially important to be aware of metabolic manifestations and serious complications that affect other organs and cancer risks. Chronic HCV infection itself contributes to de novo development of insulin resistance and hepatic steatosis, both of which increase the risk of cardiovascular diseases. Through these metabolic pathways (as well as through other hypothesized mechanisms that involve lipid metabolism, systemic inflammatory signals, and endothelial dysfunction), chronic HCV infection also contributes to significant systemic cardiovascular morbidity and mortality. While chronic HCV infection contributes to incident development of metabolic complications, the presence of concurrent metabolic diseases also contributes to disease progression, such as higher risks of hepatocellular carcinoma and progression to advanced fibrosis, among patients with chronic HCV infection. The implications of these observations are particularly important given the rising prevalence of obesity and metabolic syndrome in the United States and worldwide. Furthermore, concurrent nonalcoholic fatty liver disease, either as a result of underlying metabolic syndrome or as a direct result of HCV-induced fatty liver disease, further complicates the management of chronic HCV-infected patients. Greater awareness is needed toward the systemic manifestations of chronic HCV infection, with focused attention on the associated metabolic manifestations and complications. Successful treatment and cure of chronic HCV infection with the currently available, highly effective antiviral therapies will significantly improve long-term outcomes among these patients. It is also important to recognize and address the associated metabolic manifestations and complications to reduce cardiovascular-related morbidity and mortality.

Hepatitis C Virus, Insulin Resistance, and Steatosis

Hepatitis C virus (HCV) is one of the main causes of liver disease worldwide. Liver steatosis is a common finding in many hepatic and extrahepatic disorders, the most common being metabolic syndrome (MS). Over time, it has been shown that the frequent coexistence of these two conditions is not coincidental, since many epidemiological, clinical, and experimental studies have indicated HCV to be strongly associated with liver steatosis and numerous metabolic derangements. Here, we present an overview of publications that provide clinical evidence of the metabolic effects of HCV and summarize the available data on the pathogenetic mechanisms of this association. It has been shown that HCV infection can induce insulin resistance (IR) in the liver and peripheral tissues through multiple mechanisms. Substantial research has suggested that HCV interferes with insulin signaling both directly and indirectly, inducing the production of several proinflammatory cytokines. HCV replication, assembly, and release from hepatocytes require close interactions with lipid droplets and host lipoproteins. This modulation of lipid metabolism in host cells can induce hepatic steatosis, which is more pronounced in patients with HCV genotype 3. The risk of steatosis depends on several viral factors (including genotype, viral load, and gene mutations) and host features (visceral obesity, type 2 diabetes mellitus, genetic predisposition, medication use, and alcohol consumption). HCV-related IR and steatosis have been shown to have a remarkable clinical impact on the prognosis of HCV infection and quality of life, due to their association with resistance to antiviral therapy, progression of hepatic fibrosis, and development of hepatocellular carcinoma. Finally, HCV-induced IR, oxidative stress, and changes in lipid and iron metabolism lead to glucose intolerance, arterial hypertension, hyperuricemia, and atherosclerosis, resulting in increased cardiovascular mortality.

Elevated serum α-fetoprotein levels in patients with chronic hepatitis C virus genotype 4: not the end of the story

BACKGROUND AND AIM

Elevated serum α-fetoprotein (AFP) is not uncommonly seen among patients with chronic hepatitis C. This study aimed to identify clinical characteristics, histological characteristics, and biochemical markers associated with increased serum AFP levels in hepatitis C virus genotype 4-infected patients with no evidence of hepatocellular carcinoma and to determine the effect of lifestyle modification on these parameters.

METHODS

The study included 447 chronic hepatitis C patients with no evidence of hepatocellular carcinoma and 100 healthy controls. They underwent liver biopsies, homeostasis model assessment-insulin resistance (HOMA-IR), measurement of serum insulin, leptin, adiponectin, tumor necrosis factor-α, and interleukin-6 levels by an enzyme-linked immunosorbent assay, and assessment of AFP levels. Eighty patients with HOMA-IR greater than 3 received prospective longitudinal lifestyle intervention.

RESULTS

In a multivariate analysis, platelet count less than 140×10/cm, a mean platelet volume of at least 9.5 fl, a neutrophil-lymphocyte ratio (NLR) of at least 2, an aspartate transaminase level of at least 55 IU/l, a γ-glutamyl transpeptidase level of at least 40 IU/l, an albumin level of up to 3.8 g/dl, HOMA-IR greater than 3, a leptin level of at least 10 pg/ml, an iron level of at least 165 μg/dl, a ferritin level of at level 175 ng/ml, and hepatic fibrosis F3-F4 were found to be independently associated with elevated AFP levels. The lifestyle intervention significantly improved BMI, platelet indices, NLR, γ-glutamyl transpeptidase, leptin, leptin/adiponectin ratio, tumor necrosis factor-α, interleukin-6, HOMA-IR, and AFP levels.

CONCLUSION

Elevated insulin resistance, leptin, serum iron, ferritin, mean platelet volume, NLR, and advanced fibrosis, as well as decreased platelet count and serum albumin, are independently associated with an elevated AFP level. Lifestyle modification can improve (reduce) insulin resistance, leptin, leptin/adiponectin ratio, platelet count and their indices, NLR, and AFP level.

Hepatitis C and insulin action: An intimate relationship

Chronic hepatitis C virus (HCV) infection has been shown to be linked to a higher prevalence of type 2 diabetes compared with the general population or with patients with chronic hepatitis B infection and diabetes is the most common extra-hepatic manifestation of HCV. The HCV-diabetes association is due to insulin resistance (IR) that occurs early in the course of the disease even in patients without or with minimal fibrosis. The mechanisms for HCV-induced IR are only partly understood and include a direct inhibitory effect of HCV on insulin signaling pathway. IR in chronic HCV results in an increased progression rate of hepatic fibrosis, cirrhosis and hepatocellular carcinoma. Some but not all studies found that IR reduces the response rate to interferon/ribavirin therapy. Whether IR affects the response to the new direct-acting antiviral treatments is still unknown.

Hepatitis C Virus Infection Increases the Risk of Developing Chronic Kidney Disease: A Systematic Review and Meta-Analysis

BACKGROUND AND RATIONALE

Chronic kidney disease and hepatitis C virus are prevalent in the general population worldwide, and controversy exists about the impact of HCV infection on the development and progression of kidney disease.

DESIGN

A systematic review of the published medical literature was made to assess whether positive anti-HCV serologic status plays an independent impact on the development of chronic kidney disease in the adult general population. We used a random-effects model to generate a summary estimate of the relative risk of chronic kidney disease (defined by reduced glomerular filtration rate or detectable proteinuria) with HCV across the published studies. Meta-regression and stratified analysis were also conducted.

RESULTS

Twenty-three studies (n = 2,842,421 patients) were eligible, and separate meta-analyses were performed according to the outcome. Pooling results of longitudinal studies (n = 9; 1,947,034 unique patients) demonstrated a relationship between positive HCV serologic status and increased incidence of chronic kidney disease, the summary estimate for adjusted hazard ratio was 1.43 (95% confidence interval 1.23; 1.63, P = 0.0001), and between-studies heterogeneity was noted (P value by Q test <0.0001). The risk of the incidence of chronic kidney disease associated with HCV, in the subset of Asian surveys, was 1.31 (95% confidence interval 1.16; 1.45) without heterogeneity (P value by Q test = 0.6). HCV positive serology was an independent risk factor for proteinuria; adjusted odds ratio, 1.508 (95% confidence intervals 1.19; 1.89, P = 0.0001) (n = 6 studies; 107,356 unique patients).

CONCLUSIONS

HCV infection is associated with an increased risk of developing chronic kidney disease in the adult general population.

Hyperinsulinaemia and insulin signalling in the pathogenesis and the clinical course of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most prevalent cancer and is one of the leading causes of cancer-related death. The risk factors for HCC include cirrhosis, chronic viral hepatitis, heavy alcohol intake and metabolic diseases such as obesity, type 2 diabetes and metabolic syndrome. Insulin resistance is a common denominator of all of these conditions and is tethered to hyperinsulinaemia. Here, we give an overview of the recent advances linking hyperinsulinaemia to HCC development and progression. In particular, we summarise the underlying causes of hyperinsulinaemia in the setting of chronic liver diseases. We present epidemiological evidence linking metabolic diseases to HCC risk and HCC-related mortality, as well as the pathogenic cellular and molecular mechanisms explaining this relation. A better understanding of the mechanisms by which insulin participates in HCC biology might ultimately provide novel opportunities for prevention and treatment.

Inhibition of IRS-1 by hepatitis C virus infection leads to insulin resistance in a PTEN-dependent manner

Background

Hepatitis C virus (HCV) infection was recently recognized as an independent risk factor for insulin resistance (IR), the onset phase of type 2 diabetes mellitus (T2DM). Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) negatively regulates PI3K/Akt signaling pathway, which is critical for IR development and progression of cirrhosis to hepatocellular carcinoma (HCC). Here, we investigate the role of PTEN in HCV-associated IR and explored the mechanisms by which HCV regulates PTEN.

Methods

Western blotting was used to detect the levels of insulin signaling pathway components, including insulin receptor substrate-1 (IRS-1), phosphorylated IRS-1 (pIRS-1) at serine 307 (Ser307), both phosphorylated Akt (pAkt) and total Akt. A time-course experiment measuring activation of the insulin signaling pathway was performed to assess the effect of HCV infection on insulin sensitivity by examining the phosphorylation levels of Akt and GSK3β, a downstream target of Akt. Huh7.5.1 cells were transduced with a lentiviral vector expressing PTEN or PTEN shRNA, and IRS-1 and pIRS-1 (Ser307) levels were determined in both HCV-infected and uninfected cells. The pc-JFH1-core plasmid was constructed to explore the underlying mechanisms by which HCV regulated PTEN and therefore IRS-1 levels.

Results

HCV infection inhibited the insulin signaling pathway by reducing the levels of IRS-1 and pAkt/Akt while increasing phosphorylation of IRS-1 Ser307. In addition, HCV infection decreased the sensitivity to insulin-induced stimulation by inhibiting Akt and GSK3β phosphorylation. Furthermore, PTEN mRNA and protein levels were reduced upon HCV infection as well as transfection with the pc-JFH1-core plasmid. The reduction in IRS-1 level observed in HCV-infected cells was rescued to a limited extent by overexpression of PTEN, which in turn slightly reduced pIRS-1 (Ser307) level. In contrast, IRS-1 level were significantly decreased and phosphorylation of IRS-1 at Ser-307 was strongly enhanced by PTEN knockdown, suggesting that both reduction in IRS-1 level and increase in IRS-1 phosphorylation at Ser307 upon HCV infection occurred in a PTEN-dependent manner.

Conclusions

HCV infection suppresses the insulin signaling pathway and promotes IR by repressing PTEN, subsequently leading to decreased levels of IRS-1 and increased levels of pIRS-1 at Ser307. The findings provide new insight on the mechanism of HCV-associated IR.

Clinical Advances in Fibrosis Progression of Chronic Hepatitis B and C

Chronic liver diseases, such as chronic hepatitis B (CHB) and chronic hepatitis C (CHC), are characterized by the presence of liver fibrosis, which may ultimately lead to cirrhosis. The progression of fibrosis is associated with various factors. Here, we review recent advances in the study of factors related to the progression rate of CHB- and CHC-induced fibrosis. Identification of these factors and establishment of a scoring system for cirrhosis risk are particularly important for predicting cirrhosis development, planning individualized treatment, and preventing fibrosis progression.

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.

Recent advances on hepatitis C virus in dialysis population

Hepatitis C virus (HCV) infection remains common among patients undergoing regular dialysis and good evidence supports the detrimental role of HCV on survival in patients undergoing maintenance dialysis. According to an updated meta-analysis of clinical studies (n=15; 195,370 unique patients on maintenance dialysis), the summary estimate for adjusted relative risk (all-cause mortality) with anti-HCV across the published studies was 1.32 with a 95% Confidence Intervals of 1.24; 1.42, homogeneity assumption was not rejected. Various mechanisms support the excess death risk of HCV-infected patients on regular dialysis, in addition to liver disease-related mortality. The adjusted relative risk for cardiovascular mortality among HCV-infected patients on regular dialysis was 1.26 (95% Confidence Intervals, 1.10; 1.45); the increased cardiovascular mortality in anti-HCV positive patients has been associated in part to malnutrition and chronic inflammation. The current standard of care for HCV in dialysis population is combined antiviral therapy (pegylated interferon plus ribavirin) with a rate of viral response of around 60%. Triple therapy with telaprevir proved to be effective and safe in dialysis patients with HCV but only anecdotal evidence exists. Antiviral treatment of HCV-infected patients on maintenance dialysis could lead to cure the liver damage and the extrahepatic complications. The future availability of all-oral interferon/ribavirin free regimens for antiviral treatment of HCV will help nephrologists to improve survival in this high-risk group.

Serum proteomics of hepatitis C virus infection reveals retinol-binding protein 4 as a novel regulator

Persistent infection of hepatitis C virus (HCV) can lead to liver cirrhosis and hepatocellular carcinoma, which are currently diagnosed by invasive liver biopsy. Approximately 15-20 % of cases of chronic liver diseases in India are caused by HCV infection. In North India, genotype 3 is predominant, whereas genotype 1 is predominant in southern parts of India. The aim of this study was to identify differentially regulated serum proteins in HCV-infected Indian patients (genotypes 1 and 3) using a two-dimensional electrophoresis approach. We identified eight differentially expressed proteins by MS. Expression levels of one of the highly upregulated proteins, retinol-binding protein 4 (RBP4), was validated by ELISA and Western blotting in two independent cohorts. We also confirmed our observation in the JFH1 infectious cell culture system. Interestingly, the HCV core protein enhanced RBP4 levels and partial knockdown of RBP4 had a positive impact on HCV replication, suggesting a possible role for this cellular protein in regulating HCV infection. Analysis of RBP4-interacting partners using a bioinformatic approach revealed novel insights into the possible involvement of RBP4 in HCV-induced pathogenesis. Taken together, this study provided information on the proteome profile of the HCV-infected Indian population, and revealed a link between HCV infection, RBP4 and insulin resistance.