Mechanisms of Disease: HCV-induced liver injury

Utilization of hepatitis C virus infected donors in heart transplant recipients with elevated MELD-XI score

BACKGROUND

The advent of direct-acting antivirals has helped to increase the safe utilization of organs from hepatitis C virus positive (HCV+) donors. However, the outcomes of heart transplantation (HT) using an HCV+ donor are unclear in recipients with underlying liver disease represented by an elevated model for end-stage liver disease excluding international normalized ratio (MELD-XI).

METHODS

The United Network of Organ Sharing database was queried from Jan 2016 to Dec 2021. Post-transplant outcomes stratified by recipient MELD-XI score (low <10.37, medium, 10.38-13.39, and high >13.4) was compared between patients with HT from HCV+ (N = 792) and patients with HT from HCV-negative donors (N = 15,266).

RESULTS

The median MELD-XI score was comparable (HCV+, 12.1, vs. HCV-negative, 11.8, p = .37). In the HCV+ group, donors were older (33 vs. 31 years, p < .001). Ischemic time of donor hearts (3.48 vs. 3.28 h, p < .001) and travel distance (250 vs. 157 miles, p < .001) were longer in HCV+ group. In the Kaplan Meier analysis with a median follow-up of 750 days, survival was comparable between the two groups (2-year survival, MELD-XI Low: HCV+, 92.4 ± 3.6% vs. HCV-negative, 91.1 ±.8%, p = .83, Medium: HCV+ 89.2 ± 4.3% vs. HCV-negative, 88.2 ± 1.0%, p = .68, and High: HCV+, 84.9 ± 4.5% vs. HCV-negative, 84.6 ± 1.1%, p = .75) In multivariate Cox hazard models, HCV donors were not associated with mortality in each MELD-XI subgroup (Low: adjusted hazard ratio (aHR), 1.02, p = .94; Medium: aHR, .95, p = .81; and High: aHR, .93, p = .68).

CONCLUSION

Utilization of HCV+ hearts was not associated with an increased risk of adverse outcomes in recipients with an elevated MELD- XI score.

The Role of Non-Coding RNAs in Liver Disease, Injury, and Regeneration

Non-coding RNAs (ncRNAs) have diverse functions in health and pathology in many tissues, including the liver. This review highlights important microRNAs (miRs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) in liver disease and regeneration. Greater attention is given to more prevalent and well characterized RNAs, including: miR-122, miR-21, the let-7 family of miRs, miR-451a, miR-144, and MALAT1.

Innate-like bystander-activated CD38+ HLA-DR+ CD8+ T cells play a pathogenic role in patients with chronic hepatitis C

BACKGROUND AND AIMS

HCV-specific T cells are few and exhausted in patients with chronic hepatitis C (CHC). Whether these T cells are responsible for the liver damage and fibrosis is still debated. However, cluster of differentiation 38-positive (CD38⁺ ) human leukocyte antigen DR-positive (HLA-DR⁺ ) CD8⁺ T cells are regarded as bystander CD8⁺ T cells that cause liver injury in acute hepatitis. We propose that these innate CD8⁺ T cells play a pathogenic role in CHC.

METHODS

Lymphocytes from peripheral blood were obtained from 108 patients with CHC and 43 healthy subjects. Immunophenotyping, functional assays, T-cell receptor (TCR) repertoire, and cytotoxic assay of CD38⁺ HLA-DR⁺ CD8⁺ T cells were studied.

RESULTS

The percentage of CD38⁺ HLA-DR⁺ CD8⁺ T cells increased significantly in patients with CHC. These cells expressed higher levels of effector memory and proinflammatory chemokine molecules and showed higher interferon-γ production than CD38^- HLA-DR^- CD8 T cells. They were largely composed of non-HCV-specific CD8⁺ T cells as assessed by HLA-A2-restricted pentamers and next-generation sequencing analysis of the TCR repertoire. In addition, these CD38⁺ HLA-DR⁺ CD8⁺ T cells had strong cytotoxicity, which could be inhibited by anti-DNAX accessory molecule 1, anti-NKG2 family member D, and anti-natural killer NKp30 antibodies. Lastly, the percentage of CD38⁺ HLA-DR⁺ CD8⁺ T cells was significantly associated with liver injury and fibrosis and decreased significantly along with serum alanine aminotransferase normalization after successful direct-acting antiviral treatment.

CONCLUSIONS

The TCR-independent, cytokine-responsive bystander CD38⁺ HLA-DR⁺ CD8⁺ T cells are strongly cytotoxic and play a pathogenic role in patients with CHC.

Chronic Hepatitis C Pathogenesis: Immune Response in the Liver Microenvironment and Peripheral Compartment

Chronic hepatitis C (CHC) pathogenic mechanisms as well as the participation of the immune response in the generation of liver damage are still a topic of interest. Here, we evaluated immune cell populations and cytokines in the liver and peripheral blood (PB) to elucidate their role in CHC pathogenesis. B, CTL, Th, Treg, Th1, Th17, and NK cell localization and frequency were evaluated on liver biopsies by immunohistochemistry, while frequency, differentiation, and functional status on PB were evaluated by flow cytometry. TNF-α, IL-23, IFN-γ, IL-1β, IL-6, IL-8, IL-17A, IL-21, IL-10, and TGF-β expression levels were quantified in fresh liver biopsy by RT-qPCR and in plasma by CBA/ELISA. Liver CTL and Th1 at the lobular area inversely correlated with viral load (r = −0.469, p =0.003 and r = −0.384, p = 0.040). Treg correlated with CTL and Th1 at the lobular area (r = 0.784, p < 0.0001; r = 0.436, p = 0.013). Th17 correlated with hepatic IL-8 (r = 0.52, p < 0.05), and both were higher in advanced fibrosis cases (Th17 p = 0.0312, IL-8 p = 0.009). Hepatic cytokines were higher in severe hepatitis cases (IL-1β p = 0.026, IL-23 p = 0.031, IL-8 p = 0.002, TGF-β, p= 0.037). Peripheral NK (p = 0.008) and NK dim (p = 0.018) were diminished, while NK bright (p = 0.025) was elevated in patients vs. donors. Naïve Th (p = 0.011) and CTL (p = 0.0007) were decreased, while activated Th (p = 0.0007) and CTL (p = 0.0003) were increased. IFN-γ production and degranulation activity in NK and CTL were normal. Peripheral cytokines showed an altered profile vs. donors, particularly elevated IL-6 (p = 0.008) and TGF-β (p = 0.041). Total hepatic CTLs favored damage. Treg could not prevent fibrogenesis triggered by Th17 and IL-8. Peripheral T-lymphocyte differentiation stage shift, elevated cytokine levels and NK-cell count decrease would contribute to global disease.

Viral hepatitis update: Progress and perspectives

Viral hepatitis, secondary to infection with hepatitis A, B, C, D, and E viruses, are a major public health problem and an important cause of morbidity and mortality. Despite the huge medical advances achieved in recent years, there are still points of conflict concerning the pathogenesis, immune response, development of new and more effective vaccines, therapies, and treatment. This review focuses on the most important research topics that deal with issues that are currently being solved, those that remain to be solved, and future research directions. For hepatitis A virus we will address epidemiology, molecular surveillance, new susceptible populations as well as environmental and food detections. In the case of hepatitis B virus, we will discuss host factors related to disease, diagnosis, therapy, and vaccine improvement. On hepatitis C virus, we will focus on pathogenesis, immune response, direct action antivirals treatment in the context of solid organ transplantation, issues related to hepatocellular carcinoma development, direct action antivirals resistance due to selection of resistance-associated variants, and vaccination. Regarding hepatitis D virus, we describe diagnostic methodology, pathogenesis, and therapy. Finally, for hepatitis E virus, we will address epidemiology (including new emerging species), diagnosis, clinical aspects, treatment, the development of a vaccine, and environmental surveillance.

Hepatic stellate cells - from past till present: morphology, human markers, human cell lines, behavior in normal and liver pathology

Hepatic stellate cell (HSC), initially analyzed by von Kupffer, in 1876, revealed to be an extraordinary mesenchymal cell, essential for both hepatocellular function and lesions, being the hallmark of hepatic fibrogenesis and carcinogenesis. Apart from their implications in hepatic injury, HSCs play a vital role in liver development and regeneration, xenobiotic response, intermediate metabolism, and regulation of immune response. In this review, we discuss the current state of knowledge regarding HSCs morphology, human HSCs markers and human HSC cell lines. We also summarize the latest findings concerning their roles in normal and liver pathology, focusing on their impact in fibrogenesis, chronic viral hepatitis and liver tumors.

Mechanisms for increased risk of diabetes in chronic liver diseases

OBJECTIVE

Patients with chronic liver disease (CLD), both non-alcoholic fatty liver disease (NAFLD) and chronic hepatitis C (CHC), are at high risk of diabetes (T2D), but mechanisms are still unknown. Muscle/liver insulin resistance (IR) and pancreatic dysfunction are the major metabolic defects leading to T2D. However, if the risk of T2D in CLD patients is because of reduced insulin response and/or to IR, and the impact of liver histology has not been investigated.

DESIGN

We studied 220 non-T2D patients with chronic liver disease (129 NAFLD, BMI = 27.3 kg/m² ; 91 CHC, BMI = 25.0 kg/m² ) that received a 75-gram oral glucose tolerance test (OGTT) with the measurement of glucose and insulin concentrations for 2 hours, glucose tolerance (NGT vs IGT) and liver biopsy. The results were compared to 26 controls (CT-NGT, BMI = 25.6 kg/m² ). We evaluated peripheral insulin sensitivity (OGIS), OGTT-insulin response (ΔAUC-I/ΔAUC-G) and disposition-index (DI = OGIS∙ΔAUC-I/ΔAUC-G) for the risk to develop T2D.

RESULTS

NAFLD had increased muscle IR (associated to NASH, steatosis and fibrosis), higher than in CHC or CT-NGT (OGIS = 8.9 vs 11.3 and 10.5 mL/min kg, P < .0001). In NAFLD, OGTT-insulin response (ΔAUC-I/ΔAUC-G) was the highest while it was significantly decreased in CHC (2.2 vs 1.1 and 1.6, NAFLD vs. CHC and CT-NGT, P < .005). The highest T2D risk (low DI) was observed in CHC-IGT (7.5), CHC-NGT (13.5) and NAFLD-IGT (10.8) vs CT-NGT (14.9, all P < .0001), but not in NAFL-NGT or NASH-NGT.

CONCLUSION

We observed an increased T2D risk in NAFLD-IGT, CHC-IGT and CHC-NGT mainly because of reduced OGTT-insulin response, while insulin response in NAFLD-NGT compensates the IR thus maintaining normal glycaemia.

Direct-acting antivirals restore systemic redox homeostasis in chronic HCV patients

Chronic hepatitis C therapy has completely changed in the last years due to the availability of direct-acting antivirals (DAAs). Removing the virus may be not enough since chronic infection deeply modifies immune system and cellular metabolism along decades of inflammation. Oxidative stress plays a significant role in maintaining systemic inflammation during chronic HCV infection. Other than removing the virus, effective therapy could counteract oxidative stress. This study investigated the impact of DAA treatment on circulating markers of oxidative stress and antioxidant defence in a cohort of patients affected by chronic hepatitis C. To this, an observational study on 196 patients who started therapy with DAA for HCV-related hepatitis was performed. Patients were assessed at baseline, 4 weeks after the initiation of therapy (4wks), at the end of treatment (EoT), and 12 weeks after the EoT (SVR12). Circulating oxidative stress was determined by measuring serum hydroxynonenal (HNE)- and malondialdehyde (MDA)-protein adducts, and 8-hydroxydeoxyguanosine (8-OHdG). Antioxidant status was evaluated by measuring the enzymatic activity and mRNA expression of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in peripheral blood mononuclear cells. We observed a reduction of serum 8-OHdG at 4wks, while the circulating level of both HNE- and MDA-protein adducts diminished at EoT; all these markers persisted low at SVR12. On the other side, we reported an increase in the enzymatic activity of all the antioxidant enzymes in PBMC at EoT and SVR12. Taking into account circulating 8-OHdG and antioxidant enzyme activities, patients with high fibrosis stage were those that had the most benefit from DAA therapy. To conclude, this study indicates that treatment with DAAs improves the circulating redox status of patients affected by chronic hepatitis C. This positive impact of DAA therapy may be related to its effectiveness on cutting down viremia and pro-inflammatory markers.

Hepatitis C virus infection induces endoplasmic reticulum stress and apoptosis in human fetal liver stem cells

The cellular mechanisms by which hepatitis C virus (HCV) replication might mediate cytopathic effects are controversial and not entirely clear. In this study, we found that blood-borne HCV (bbHCV) infection could lead to endoplasmic reticulum (ER)-stress and mitochondria-related/caspase-dependent apoptosis at the early stages of infection based on use of the highly efficient bbHCV cell culture model established previously. Sections of bbHCV-infected human fetal liver stem cells (hFLSCs) revealed convolution and nonlinear ER, cell vacuolization, swelling of mitochondria, and numerous double membrane vesicles (DMVs). The percentage of apoptotic hFLSCs infected by bbHCV reached 29.8% at 16 h postinfection, and the amount of cytochrome c increased remarkably in the cytosolic protein fraction. However, over time, apoptosis was inhibited due to the activation of NF-κB. The expression of NF-κB-p65, Bcl-xL, XIAP, and c-FLIPL in hFLSCs was increased significantly 24 h after in infection by bbHCV. The accelerated cell death cycles involving apoptosis, regeneration and repair by bbHCV infection might give rise to the development of cirrhosis, and ultimately to hepatocellular carcinogenesis. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Emricasan (IDN-6556) Lowers Portal Pressure in Patients With Compensated Cirrhosis and Severe Portal Hypertension

Caspases play a central role in apoptosis, inflammation, and fibrosis. They produce hemodynamically active, proinflammatory microparticles that cause intrahepatic inflammation, vasoconstriction, and extrahepatic splanchnic vasodilation. Emricasan is a pan-caspase inhibitor that lowers portal hypertension (PH) and improves survival in murine models of cirrhosis. This exploratory study assessed whether emricasan lowers PH in patients with compensated cirrhosis. This multicenter, open-label study enrolled 23 subjects with compensated cirrhosis and PH (hepatic vein pressure gradient [HVPG] >5 mm Hg). Emricasan 25 mg twice daily was given for 28 days. HVPG measurements were standardized and performed before and after emricasan. A single expert read all HVPG tracings. Median age was 59 (range 49-80); 70% were male. Cirrhosis etiologies were nonalcoholic steatohepatitis and hepatitis C virus. Subjects were Child class A (87%) with a median Model for End-Stage Liver Disease score of 8 (range 6-15). Twelve had severe PH (HVPG ≥12 mm Hg). Overall, there was no significant change in HVPG after emricasan (mean [standard deviation, SD] -1.1 [4.57] mm Hg). HVPG decreased significantly (mean [SD] -3.7[4.05] mm Hg; P = 0.003) in those with severe PH: 4/12 had a ≥20% decrease, 8/12 had a ≥10% decrease, and 2/12 HVPG decreased below 12 mm Hg. There were no significant changes in blood pressure or heart rate. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) decreased significantly in the entire group and in those with severe PH. Serum cleaved cytokeratin 18 and caspase-3/7 decreased significantly. Emricasan was well tolerated. One subject discontinued for nonserious adverse events. Conclusion: Emricasan administered for 28 days decreased HVPG in patients with compensated cirrhosis and severe PH; an effect upon portal venous inflow is likely, and concomitant decreases in AST/ALT suggest an intrahepatic anti-inflammatory effect.

Direct-acting antivirals-based therapy decreases hepatic fibrosis serum biomarker microfibrillar-associated protein 4 in hepatitis C patients

Background/Aims

An estimated 80 million people worldwide are infected with viremic hepatitis C virus (HCV). Even after eradication of HCV with direct acting antivirals (DAAs), hepatic fibrosis remains a risk factor for hepatocarcinogenesis. Recently, we confirmed the applicability of microfibrillar-associated protein 4 (MFAP4) as a serum biomarker for the assessment of hepatic fibrosis. The aim of the present study was to assess the usefulness of MFAP4 as a biomarker of liver fibrosis after HCV eliminating therapy with DAAs.

Methods

MFAP4 was measured using an immunoassay in 50 hepatitis C patients at baseline (BL), the end-of-therapy (EoT), and the 12-week follow-up (FU) visit. Changes in MFAP4 from BL to FU and their association with laboratory parameters including alanine aminotransferase (ALT), aspartate aminotransferase (AST), platelets, the AST to platelet ratio index (APRI), fibrosis-4 score (FIB-4), and albumin were analyzed.

Results

MFAP4 serum levels were representative of the severity of hepatic fibrosis at BL and correlated well with laboratory parameters, especially APRI (Spearman correlation, R²=0.80). Laboratory parameters decreased significantly from BL to EoT. MFAP4 serum levels were found to decrease from BL and EoT to FU with high statistical significance (Wilcoxon p<0.001 for both).

Conclusions

Our findings indicate that viral eradication resulted in reduced MFAP4 serum levels, presumably representing a decrease in hepatic fibrogenesis or fibrosis. Hence, MFAP4 may be a useful tool for risk assessment in hepatitis C patients with advanced fibrosis after eradication of the virus.

Immunometabolic Effect of Cholesterol in Hepatitis C Infection: Implications in Clinical Management and Antiviral Therapy

Hepatitis C virus (HCV) is a lipid-enveloped virion particle that causes infection to the liver, and as part of its life cycle, it disrupts the host lipid metabolic machinery, particularly the cholesterol synthesis pathway. The innate immune response generated by liver resident immune cells is responsible for successful viral eradication. Unfortunately, most patients fail to eliminate HCV and progress to chronic infection. Chronic infection is associated with hepatic fat accumulation and inflammation that triggers fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Despite that the current direct-acting antiviral agents have increased the cure rate of HCV infection, viral genotype and the host genetic background influence both the immune response and lipid metabolism. In this context, recent evidence has shown that cholesterol and its derivatives such as oxysterols might modulate and potentialize the hepatic innate immune response generated against HCV. The impairment of the HCV life cycle modulated by serum cholesterol could be relevant for the clinical management of HCV-infected patients before and after treatment. Alongside, cholesterol levels are modulated either by genetic variations in IL28B, ApoE, and LDLR or by dietary components. Indeed, some nutrients such as unsaturated fatty acids have demonstrated to be effective against HCV replication. Thus, cholesterol modifications may be considered as a new adjuvant strategy for HCV infection therapy by providing a biochemical tool that guides treatment decisions, an improved treatment response and favoring viral clearance. Herein, the mechanisms by which cholesterol contributes to the immune response against HCV infection and how genetic and environmental factors may affect this role are reviewed.

Genetic variants upstream of TNFAIP3 in the 6q23 region are associated with liver disease severity in HIV/HCV-coinfected patients: A cross-sectional study

BACKGROUND

TNFAIP3 is a crucial hepatoprotective factor due to its anti-inflammatory, anti-apoptotic, anti-oxidant and pro-regenerative functions. The aim of this study was to analyze the associations between genetic variants upstream of TNFAIP3 (rs675520, rs9376293 and rs6920220) and liver fibrosis severity and inflammation in HIV/HCV-coinfected patients.

METHODS

A cross-sectional study was carried out in 215 HIV/HCV-coinfected patients, who underwent a liver biopsy. TNFAIP3 polymorphisms were genotyped using GoldenGate® assay. Outcome variables were: a) liver fibrosis (Metavir score) [fibrosis stage (F0, F1, F2, F3 and F4) and advanced fibrosis and cirrhosis (F ≥ 3 and F4, respectively)]; b) non-invasive indexes [FIB-4, APRI, and their cut-offs (FIB-4 ≥ 3.25 and APRI≥1.5)]; c) inflammation-related biomarkers (leptin, HGF, NGF, sFasL, sFas, MIF, HA, Ang-2, TIMP1, MMP1 and MMP2).

RESULTS

Patients with rs675520 AG/GG genotypes had decreased odds of having cirrhosis (F4) and advanced fibrosis (FIB-4 ≥ 3.25 and APRI≥1.5) [adjusted Odd Ratio (aOR) = 0.30 (p = 0.025), aOR = 0.20 (p = 0.014), and aOR = 0.34 (p = 0.017), respectively] and lower levels of FIB-4 and APRI [adjusted arithmetic mean ratio (aAMR) = 0.76 (p = 0.003) and aAMR = 0.72 (p = 0.006), respectively]. Patients with rs9376293 CT/CC genotypes had decreased odds of APRI≥1.5 [aOR = 0.39 (p = 0.030)] and lower levels of APRI [aAMR = 0.77 (p = 0.018)]. Patients with rs6920220 AG/AA genotypes had higher odds of having FIB-4 ≥ 3.25 [aOR = 3.72 (p = 0.043)]. Moreover, rs675520 AG/GG genotypes, compared to AA genotype, were associated with lower levels of leptin and NGF (p = 0.002 and p = 0.001, respectively) and higher levels of sFas, MIF, TIMP1 and MMP2 (p = 0.004, p = 0.007, p = 0.020 and p = 0.036, respectively). Also, rs9376293 CT/CC genotypes were related to lower leptin levels (p = 0.026) and higher sFas, MIF, TIMP1 and MMP2 levels (p = 0.029, p = 0.040, p = 0.022 and p = 0.024, respectively).

CONCLUSIONS

Genetic variants upstream of TNFAIP3 were associated with the liver fibrosis severity and inflammation in HIV/HCV-coinfected patients.

Incidence of Post-Liver Transplant Hepatic Dysfunction After Sustained Virologic Response Following Direct-Acting Anti-Hepatitis C Therapy

OBJECTIVES

Newly developed, direct-acting antiviral therapy is effective in over 90% of cases to eradicate hepatitis C virus infection. Direct-acting antiviral therapy is also effective in liver transplant recipients with recurrent hepatitis C virus infection. However, hepatic function after sustained virologic response in transplant recipients is unknown. Here, we aimed to uncover the incidence of hepatic dysfunction in this patient group at our center.

MATERIALS AND METHODS

Our study included 40 consecutive (January 2014 to February 2016) and compliant posttransplant recipients who achieved sustained viral response from direct-acting antiviral therapy. Patients were investigated for incidence and causes of hepatic dysfunction.

RESULTS

In our patient group, 4 (10%) experienced hepatic dysfunction with stable baseline immunosuppression, with 2 having drastic increases in alanine aminotransferase at 15 and 32 weeks after direct-acting antiviral therapy. Biopsies showed hepatitis, and both patients were treated with hydrocortisone, which increased their baseline immunosuppression. The 3rd patient had an increase in bilirubin at 21 weeks posttherapy, with biopsy showing macrovascular steatosis. The 4th patient had a rapid increase in bilirubin at 7 weeks after direct-acting antiviral therapy, with biopsy showing significant duct loss.

CONCLUSIONS

During the study period, 10% of patients experienced hepatic dysfunction after sustained viral response. Presumed causative factors included partial immune reconstitution and nonalcoholic fatty liver disease.

Serum biomarkers for diagnosis and monitoring viral hepatitis and hepatocellular carcinoma

INTRODUCTION

Chronic liver disease due to viral hepatitis continues to be a major global health concern. Timely diagnosis and treatment will prevent cirrhosis, risk of hepatocellular carcinoma (HCC), and requirement for liver transplantation. Numerous serum biomarkers are available for viral hepatitis that are helpful in diagnosis, measuring severity, progression of disease, evaluating the best therapeutic options, and monitoring antiviral treatment response. Determining the clinical use of available diagnostic tests can be challenging for the health care provider. Areas covered: This review article attempts to summarize the established and emerging serological markers for diagnosis and managing viral hepatitis. The literature search was performed in February 2018 and included MEDLINE and Embase databases for recent relevant literature on biomarkers for viral hepatitis. Expert Commentary: Despite the discovery of several candidate biomarkers, translating these to clinical practice in viral hepatitis and HCC remains challenging. While limited availability of the new biomarkers in prevalent geographic areas and significant cost remain major obstacles, there have been exciting developments in this field. Understanding the detection limits and sensitivity of these markers and translating them into clinical use is important in management of viral hepatitis and complications of liver disease such as cirrhosis and hepatocellular cancer.

Analysis of Plasma Tenascin-C in Post-HCV Cirrhosis: A Prospective Study

BACKGROUND AND AIM

Hepatitis C virus (HCV)-related cirrhosis, one of the most common etiologies of liver cirrhosis in the Western world, is a risk factor for hepatocellular carcinoma. To confirm and improve current effectiveness of screening and prognosis of patients with established cirrhosis, a credible, simple plasma biomarker is needed. Hepatic stellate cell activation, a pivotal event in cirrhosis development, results in increased secretion of extracellular matrix proteins, including tenascin-C (TnC). Herein, we tested TnC as a simple biomarker to identify cirrhotic patients with active HCV infection from those with HCV eradication.

METHODS

A prospective study of subjects with HCV-related cirrhosis, stratified into two groups, HCV or virologic cure, was conducted. Plasma TnC expression was measured by ELISA and Western blots. TnC values were correlated with markers of liver injury and ROC analyses performed between groups.

RESULTS

The HCV cirrhotic cohort, consisting mostly of men (56%), Caucasians (76%), and genotype 1a or 1b (84%), was compared to healthy controls (HCs). Plasma TnC was significantly higher in HCV cirrhotic patients with active infection compared to HCs (P < 0.0001) and virologic cure (P < 0.0001). TnC concentrations in virologic cure subjects were not statistically different from HCs. TnC levels correlated with AST, platelets, MELD, APRI, FIB-4, and Child-Pugh score. TnC and AST together were significantly better indicators of cirrhosis in patients with active HCV infection than other markers tested.

CONCLUSIONS

TnC and AST provided the best model for discriminating HCV cirrhotics with active infection from HC and virologic cure cohorts over current liver injury markers, suggesting TnC as a potential indicator of ongoing hepatic injury and inflammation.

Chronic hepatitis C liver microenvironment: role of the Th17/Treg interplay related to fibrogenesis

The role of the different lymphocyte populations in liver microenvironment of chronic hepatitis C (CHC) patients is still matter of debate. Since Th17 and Treg have opposite functions, their balance could affect disease progression. The aim was to explore liver microenvironment and its peripheral blood counterpart in adult CHC patients. CD4⁺ lymphocytes were predominant in the liver, with high Foxp3⁺ but low IL-17A⁺ frequency. IL-17A⁺ lymphocytes and IL-17A⁺/Foxp3⁺ ratio displayed association with advanced fibrosis (p = 0.0130; p = 0.0236, respectively), while Foxp3⁺ lymphocytes and IL-10 expression level inversely correlated with fibrosis severity (p = 0.0381, p = 0.0398, respectively). TGF-β/IL-6 ratio correlated with IL-17A⁺/Foxp3⁺ ratio (p = 0.0036, r = 0.5944) and with IL-17A⁺ lymphocytes (p = 0.0093; r = 0.5203). TNF-α and TGF-β were associated with hepatitis severity (p = 0.0409, p = 0.0321). Peripheral blood lymphocyte frequency was not associated with liver damage. There are functionally different immune cell populations actively involved in liver damage, but the liver cytokine milieu actually drives the pathogenesis. The intrahepatic Foxp3⁺ lymphocytes predominance beside the low IL-17A⁺ lymphocytes frequency, delineate a skewed IL-17A⁺/Foxp3⁺ balance towards Foxp3⁺ lymphocytes. However, the IL-17A⁺ lymphocytes association with advanced fibrosis denotes their role in the pathogenesis. Therefore, the interplay between Th17 and Treg conditions liver fibrogenesis.

Quantitative proteome analysis of plasma microparticles for the characterization of HCV-induced hepatic cirrhosis and hepatocellular carcinoma

PURPOSE

Hepatocellular carcinoma (HCC) is the most common primary malignant liver tumor and a leading cause of cancer-related deaths worldwide. Cirrhosis induced by hepatitis-C virus (HCV) infection is the most critical risk factor for HCC. However, the mechanism of HCV-induced carcinogenesis is not fully understood. Plasma microparticles (PMP) contribute to numerous physiological and pathological processes and contain proteins whose composition correlates to the respective pathophysiological conditions.

EXPERIMENTAL DESIGN

We analyzed PMP from 22 HCV-induced cirrhosis patients, 16 HCV-positive HCC patients with underlying cirrhosis and 18 healthy controls. PMP were isolated using ultracentrifugation and analyzed via label-free LC-MS/MS.

RESULTS

We identified 840 protein groups and quantified 507 proteins. 159 proteins were found differentially abundant between the three experimental groups. PMP in both disease entities displayed remarkable differences in the proteome composition compared to healthy controls. Conversely, the proteome difference between both diseases was minimal. GO analysis revealed that PMP isolated from both diseases were significantly enriched in proteins involved in complement activation, while endopeptidase activity was downregulated exclusively in HCC patients.

CONCLUSION

This study reports for the first time a quantitative proteome analysis for PMP from patients with HCV-induced cirrhosis and HCC. Data are available via ProteomeXchange with identifier PXD005777.

Activation of hepatic stellate cells by the ubiquitin C-terminal hydrolase 1 protein secreted from hepatitis C virus-infected hepatocytes

Hepatitis C virus (HCV) infection of hepatocytes promotes liver fibrosis by activation of hepatic stellate cells (HSCs) and excessive deposition of extracellular matrix in liver tissue. Whether or not host factors released from the HCV-infected hepatocytes play role in HSCs activation is unclear. In this study, HSCs were activated by the conditioned medium derived from HCV replicon cells. Secretomic profiling of HCV replicon cells and the parental Huh7 cells revealed ubiquitin carboxy-terminal hydrolase L1 (UCHL1) as a novel secreted protein from HCV-infected hepatocytes. UCHL1 expression in hepatocytes was induced by HCV infection. UCHL1 was expressed in the liver and found in the plasma of patients with chronic hepatitis C. Molecular analysis by use of the anti-UCHL1 neutralization antibody and purified UCHL1 protein showed that secreted UCHL1 protein was bound to the cell surface of HSCs and activated JNK signaling leading to overexpression of alpha-smooth muscle actin and the activation of HSCs. These results provide further for understanding the underlying mechanism in HCV-mediated hepatic fibrogenesis.

Hepatocyte-specific expression of constitutively active Alk5 exacerbates thioacetamide-induced liver injury in mice

While Transforming growth factor-βs (Tgf-βs) have been known to play an important role in liver fibrosis through an activation of Hepatic Stellate Cells (HSC), their fibrotic role on hepatocytes in liver damage has not been addressed thoroughly. To shed more light on the hepatocyte-specific role of Tgf-β signaling during liver fibrosis, we generated transgenic mice expressing constitutively active Tgf-β type I receptor Alk5 under the control of albumin promoter. Uninjured mice with increased Tgf-β/Alk5 signaling in hepatocytes (caAlk5/Alb-Cre mice) did not show characteristics related to hepatocyte death, fibrosis and inflammation. When subjected to thioacetamide (TAA) treatment, caAlk5/Alb-Cre mice exhibited more severe liver injury, when compared to control littermates. After TAA administration for 12 weeks, an increase in pathological changes was evident in caAlk5/Alb-Cre livers, with higher number of infiltrating cells in the portal and periportal area. Immunohistochemistry for F4/80, myeloperoxidase and CD3 showed that there was an increased accumulation of macrophages, neutrophils and T-lymphocytes, respectively, in caAlk5/Alb-Cre livers. Coincidently, we observed an exacerbated liver damage as seen by increases in serum aminotransferase level and number of apoptotic hepatocytes in caAlk5/Alb-Cre mice. Sirius staining of collagen demonstrated that the fibrotic response was worsened in caAlk5/Alb-Cre mice. The enhanced fibrosis in mutant livers was associated with marked production of α-SMA-positive myofibroblast. Hepatic expression of genes indicative of HSC activation was greater in caAlk5/Alb-Cre mice. In conclusion, our data indicated that elevation of Tgf-β signaling via Alk5 in hepatocytes is not sufficient to induce liver pathology but plays an important role in amplifying TAA-induced liver damage.

Mx1, OAS1 and OAS2 polymorphisms are associated with the severity of liver disease in HIV/HCV-coinfected patients: A cross-sectional study

The mechanisms involved in the chronic hepatitis C progression are incompletely understood. The aim was to analyze the association between 2'5'oligoadenylate synthetase 1,2 and 3 (OAS1-3) and myxovirus resistance proteins 1 (Mx1) polymorphisms and severity of liver disease in human immunodeficiency virus (HIV)/hepatitis C virus (HCV) coinfected patients. We performed a cross-sectional study in 219 patients that underwent a liver biopsy. DNA genotyping for Mx1 (rs469390), OAS1 (rs2285934), OAS2 (rs1293762) and OAS3 (rs2010604) was performed by using GoldenGate assay. The outcome variables ion liver biopsy were: (i) significant fibrosis (F ≥ 2); (ii) moderate activity grade (A ≥ 2). Additive model of inheritance for genetic association test was used. The likelihood of having significant fibrosis (F ≥ 2) was lower in patients carrying OAS2 rs1293762 A allele [adjusted odds ratio (aOR) = 0.51; p = 0.040]. Besides, the likelihood of having moderate activity grade (A ≥ 2) was higher in patients carrying Mx1 rs464397 C allele (aOR = 1.63; p = 0.028) and Mx1 rs469390 G allele (aOR = 1.97; p = 0.005), while it was lower in patients carrying OAS1 rs2285934 A allele (aOR = 0.64; p = 0.039) and OAS2 rs1293762 A allele (aOR = 0.41; p = 0.009). In conclusion, Mx1 and OAS1-2 polymorphisms were associated with the severity of liver disease in HIV/HCV-coinfected patients, suggesting a significant role in the progression of hepatic fibrosis.

Impact of Hepatitis C Virus/Schistosoma mansoni Coinfection on the Circulating Levels of HCV-NS4 Protein and Extracellular-Matrix Deposition in Patients with Different Hepatic Fibrosis Stages

Hepatitis C virus (HCV)/Schistosoma mansoni coinfection is common in Egypt and other developing countries. This study aimed to investigate the influence of HCV/S. mansoni coinfection on the concentration of HCV-nonstructural protein-4 (NS4) in addition to collagen III and matrix metalloproteinase-1 (MMP-1) in different hepatic fibrosis stages. We found that coinfected patients (N = 186) showed significantly (P < 0.05, Mann-Whitney U test) higher concentrations of HCV-NS4, collagen III, and collagen III/MMP-1 ratio (CMR) than those with HCV monoinfection (N = 104) in different fibrosis stages. Conversely, coinfected patients showed significantly lower concentrations of MMP-1 when compared with HCV monoinfection. The elevated levels of CMR in case of HCV monoinfection yielded an estimated odds ratio of 1.8 and 2.6 for developing significant fibrosis (F2-F4) and cirrhosis (F4), respectively. HCV/S. mansoni coinfection increased the risk for developing F2-F4 and F4 several fold yielding an estimated odds ratio of 11.1 and 5.2, respectively. This means that coinfected patients have a 6-fold and 2-fold increased risk of developing F2-F4 and F4, respectively, over HCV-monoinfected patients. Thus, elevated levels of HCV-NS4 and CMR in HCV/S. mansoni coinfection suggest increased susceptibility of coinfected patients, compared with those with HCV monoinfection, for accelerating hepatic fibrosis progression.

HCV-Mediated Apoptosis of Hepatocytes in Culture and Viral Pathogenesis

Chronic Hepatitis C Virus (HCV) infection is associated with progressive liver injury and subsequent development of fibrosis and cirrhosis. The death of hepatocytes results in the release of cytokines that induce inflammatory and fibrotic responses. The mechanism of liver damage is still under investigation but both apoptosis and immune-mediated processes may play roles. By observing the changes in gene expression patterns in HCV-infected cells, both markers and the causes of HCV-associated liver injury may be elucidated. HCV genotype 1b virus from persistently infected VeroE6 cells induced a strong cytopathic effect when used to infect Huh7.5 hepatoma cells. To determine if this cytopathic effect was a result of apoptosis, ultrastructural changes were observed by electron microscopy and markers of programmed cell death were surveyed. Screening of a human PCR array demonstrated a gene expression profile that contained upregulated markers of apoptosis, including tumor necrosis factor, caspases and caspase activators, Fas, Bcl2-interacting killer (BIK) and tumor suppressor protein, p53, as a result of HCV genotype 1b infection. The genes identified in this study should provide new insights into understanding viral pathogenesis in liver cells and may possibly help to identify novel antiviral and antifibrotic targets.

Distinct Roles for Intracellular and Extracellular Lipids in Hepatitis C Virus Infection

Hepatitis C is a chronic liver disease that contributes to progressive metabolic dysfunction. Infection of hepatocytes by hepatitis C virus (HCV) results in reprogramming of hepatic and serum lipids. However, the specific contribution of these distinct pools of lipids to HCV infection remains ill defined. In this study, we investigated the role of hepatic lipogenesis in HCV infection by targeting the rate-limiting step in this pathway, which is catalyzed by the acetyl-CoA carboxylase (ACC) enzymes. Using two structurally unrelated ACC inhibitors, we determined that blockade of lipogenesis resulted in reduced viral replication, assembly, and release. Supplementing exogenous lipids to cells treated with ACC inhibitors rescued HCV assembly with no effect on viral replication and release. Intriguingly, loss of viral RNA was not recapitulated at the protein level and addition of 2-bromopalmitate, a competitive inhibitor of protein palmitoylation, mirrored the effects of ACC inhibitors on reduced viral RNA without a concurrent loss in protein expression. These correlative results suggest that newly synthesized lipids may have a role in protein palmitoylation during HCV infection.

Functional dichotomy of Vδ2 γδ T cells in chronic hepatitis C virus infections: role in cytotoxicity but not for IFN-γ production

Vδ2 γδ (Vδ2) T cells, a major human γδ T cell subset, exhibit broad anti-tumor and anti-infective activity; however, their precise role in chronic hepatitis C virus (HCV) infections remains unclear. In this study, we analyzed the phenotype and function of Vδ2 T cells in 43 HCV-infected patients compared to 39 healthy controls (HCs). Vδ2 T cells from HCV-infected patients were activated and differentiated into effector cells. Vδ2 T cells in patients expressed significantly higher levels of natural killer (NK) cell markers CD56 and CD16 than in HCs, acquiring cytotoxic NK-like phenotype. The Vδ2 T cell phenotype was associated with increased cytolytic effector molecules expression in HCV-infected patients with elevated serum ALT levels. Surprisingly, Vδ2 T cells in patients had a markedly impaired capacity to produce IFN-γ. Further in vitro and in vivo analysis showed that interferon-α, which was induced during HCV infection, caused Vδ2 T cell function bias toward cytotoxicity. These results suggest a functional dichotomy for Vδ2 T cells in chronic HCV infections: a role in cytotoxicity but not for IFN-γ production, which may contribute to both the liver inflammation and HCV persistence.

Impact of patatin-like phospholipase domain-containing 3 gene polymorphism (rs738409) on severity of liver disease in HIV/hepatitis C virus-coinfected patients

OBJECTIVE

To analyze the association between patatin-like phospholipase domain-containing 3 gene (PNPLA3) rs738409 polymorphism and severity of liver disease in HIV/hepatitis C virus-coinfected patients.

METHODS

We performed a cross-sectional study of 215 patients who underwent a liver biopsy. PNPLA3 rs738409 polymorphism was genotyped using GoldenGate assay. The outcome variables were as follows: advanced fibrosis (F ≥3 and FIB-4 ≥3.25), rapid fibrosis progression (FPR ≥0.10 fibrosis units/year), severe activity grade (A≥3), and steatosis (fatty hepatocytes ≥10%). The genetic association analysis was carried out according to an additive genetic model through logistic regressions adjusted by the most significant covariables.

RESULTS

Overall, 21.4% had F at least 3, 8.9% had FIB-4 at least 3.25, 11.4% had A at least 3, 60.6% had steatosis, and 32.5% had FPR at least 0.10. For each rs738409 G allele, we found an increased frequency of patients with advanced fibrosis (F at least 3) (0% CC, 18.5% CG, and 25.2% GG; P = 0.049) and FIB-4 at least 3.25 (0% CC, 3.8% CG, and 13.2% GG; P = 0.016). Furthermore, for each rs738409 G allele, the odds of having F at least 3 increased 2.15 times (95% confidence interval=1.07; 4.35; P = 0.029) and having FIB-4 at least 3.25 increased 8.77 times (95% of confidence interval = 1.11; 69.0; P = 0.039). Note that rs738409 G allele carriers tended to higher likelihood of having FPR at least 0.10, but statistical significance was not reached (P = 0.054). Finally, we did not find any association for A at least 3 and liver steatosis.

CONCLUSION

PNPLA3 rs738409 polymorphism was associated with the severity of liver fibrosis in patients coinfected with HIV and hepatitis C virus, suggesting that this polymorphism might also play a significant role in the progression of hepatic fibrosis in this group of patients.

Oxidative Stress Attenuates Lipid Synthesis and Increases Mitochondrial Fatty Acid Oxidation in Hepatoma Cells Infected with Hepatitis C Virus

Cytopathic effects are currently believed to contribute to hepatitis C virus (HCV)-induced liver injury and are readily observed in Huh7.5 cells infected with the JFH-1 HCV strain, manifesting as apoptosis highly correlated with growth arrest. Reactive oxygen species, which are induced by HCV infection, have recently emerged as activators of AMP-activated protein kinase. The net effect is ATP conservation via on/off switching of metabolic pathways that produce/consume ATP. Depending on the scenario, this can have either pro-survival or pro-apoptotic effects. We demonstrate reactive oxygen species-mediated activation of AMP-activated kinase in Huh7.5 cells during HCV (JFH-1)-induced growth arrest. Metabolic labeling experiments provided direct evidence that lipid synthesis is attenuated, and β-oxidation is enhanced in these cells. A striking increase in nuclear peroxisome proliferator-activated receptor α, which plays a dominant role in the expression of β-oxidation genes after ligand-induced activation, was also observed, and we provide evidence that peroxisome proliferator-activated receptor α is constitutively activated in these cells. The combination of attenuated lipid synthesis and enhanced β-oxidation is not conducive to lipid accumulation, yet cellular lipids still accumulated during this stage of infection. Notably, the serum in the culture media was the only available source for polyunsaturated fatty acids, which were elevated (2-fold) in the infected cells, implicating altered lipid import/export pathways in these cells. This study also provided the first in vivo evidence for enhanced β-oxidation during HCV infection because HCV-infected SCID/Alb-uPA mice accumulated higher plasma ketones while fasting than did control mice. Overall, this study highlights the reprogramming of hepatocellular lipid metabolism and bioenergetics during HCV infection, which are predicted to impact both the HCV life cycle and pathogenesis.

HCV-infected cells and differentiation increase monocyte immunoregulatory galectin-9 production

The lectin galectin-9 may help establish and maintain chronic hepatitis C virus infection. Galectin-9 is elevated in the liver and sera of hepatitis C virus patients, induces apoptosis of hepatitis C virus-specific T cells, and increases inhibitory regulatory T cells. Kupffer cells stain strongly for galectin-9 protein in hepatitis C virus patients. In the current study, we determined stimuli that induce galectin-9 production by monocytes and macrophages in hepatitis C virus infection. With the use of real-time PCR and flow cytometry, we analyzed galectin-9 mRNA and protein from human monocytes cocultured with hepatitis C virus-infected cells or noninfectious hepatitis C virus subgenomic replicon cells. We focused on finding the stimuli for galectin-9 production. Additionally, we measured galectin-9 during monocyte-to-macrophage maturation. Finally, we examined galectin-9 in peripheral monocytes from hepatitis C virus patients using flow cytometry. Galectin-9 mRNA increased 8-fold when primary monocytes were exposed to hepatitis C virus--infected cells. Maximum induction required proximity or contact and did not require IFN-γ or hepatitis C virus virions. Coculture of monocytes with subgenomic replicon cells increased galectin-9 5-fold, and purified exosomes from infected cells stimulated galectin-9 production. Stimulation of monocyte TLR3, -7, and -8 increased galectin-9 production. Differentiation of monocytes to macrophages increased galectin-9, and nonclassic monocytes from hepatitis C virus patients had the highest levels of galectin-9. Hepatitis C virus-infected cells stimulated monocytes to produce galectin-9 in close proximity, possibly, in part, as a result of exosomes and endosomal TLRs. Differentiation of monocytes to macrophages increased galectin-9. Nonclassic monocytes from hepatitis C virus patients express the highest galectin-9 levels, suggesting they may contribute to elevated galectin-9 and adaptive immune inhibition in hepatitis C virus infection.

HCV upregulates Bim through the ROS/JNK signalling pathway, leading to Bax-mediated apoptosis

We previously reported that hepatitis C virus (HCV) infection induces Bax-triggered, mitochondrion-mediated apoptosis by using the HCV J6/JFH1 strain and Huh-7.5 cells. However, it was still unclear how HCV-induced Bax activation. In this study, we showed that the HCV-induced activation and mitochondrial accumulation of Bax were significantly attenuated by treatment with a general antioxidant, N-acetyl cysteine (NAC), or a specific c-Jun N-terminal kinase (JNK) inhibitor, SP600125, with the result suggesting that the reactive oxygen species (ROS)/JNK signalling pathway is upstream of Bax activation in HCV-induced apoptosis. We also demonstrated that HCV infection transcriptionally activated the gene for the pro-apoptotic protein Bim and the protein expression of three major splice variants of Bim (BimEL, BimL and BimS). The HCV-induced increase in the Bim mRNA and protein levels was significantly counteracted by treatment with NAC or SP600125, suggesting that the ROS/JNK signalling pathway is involved in Bim upregulation. Moreover, HCV infection led to a marked accumulation of Bim on the mitochondria to facilitate its interaction with Bax. On the other hand, downregulation of Bim by siRNA (small interfering RNA) significantly prevented HCV-mediated activation of Bax and caspase 3. Taken together, these observations suggest that HCV-induced ROS/JNK signalling transcriptionally activates Bim expression, which leads to Bax activation and apoptosis induction.

Acute and chronic immune biomarker changes during interferon/ribavirin treatment in HIV/HCV co-infected patients

Chronic viral infections lead to persistent immune activation, which is alleviated by eradicating or suppressing the infection. To understand the effects of interferon treatment on immune system activation by chronic infections, we evaluated kinetic patterns of a broad spectrum of serum biomarkers during HCV treatment in HIV/HCV co-infected patients. HCV viral load and 50 biomarkers were analysed at baseline and 27 time points during pegylated interferon-alpha and ribavirin (IFN/RBV) treatment of 12 HIV/HCV co-infected patients. We evaluated biomarker changes from baseline for each time point and biomarker correlations with clinical parameters, treatment response and liver histopathology. IL-1α, IL-12p40, IL-1RA, IP-10, MIG, MIP-1α/1β, HGF, sCD40L, TRAIL and leptin increased in the first day. IL-12p70, IL-17A, IL-10, GROα, IL-8, MCP-3, IL-4 and M-CSF peaked later during week 1. IL-1α, HGF, IP-10, MIP-1α, TRAIL, sCD40L, IL-10, IL-12p70, MCP-3, FGFb, ENA-78, TGF-β, IL-2, IFN-γ, IL-6, IL-15, IL-7 and PDGF-BB decreased below baseline over the course of treatment. Higher BMI, baseline HCV viral load and leptin levels were associated with lack of sustained virologic response. ENA-78 was associated with sustained viral response. Positive correlations were found between liver inflammation and baseline CD4 count, sVCAM and HGF; fibrosis stage and HGF; liver steatosis, BMI and leptin. Our findings suggest IFN/RBV treatment initially increases levels of several biomarkers, but eventually leads to a decline in many immune markers. These findings shed light on the relationship between IFN treatment and immune activation by chronic viral infections, such as HCV.

MicroRNA expression profiling in PBMCs: a potential diagnostic biomarker of chronic hepatitis C

The expression levels of miR-16, miR-193b, miR-199a, miR-222, and miR-324 in PBMCs were significantly higher in CHC patients compared with healthy controls and significantly different between CHC patients with HCV genotype 1 (GT-1) and non-genotype-1 (non-GT-1). Multivariate logistic regression analysis also showed that patients with high expression levels of the six target miRNAs had an approximately 7.202-fold risk of CHC compared with those with low expression levels of the target miRNAs. We concluded that the expression levels of miR-16, miR-193b, miR-199a, miR-222, and miR-324 target miRNAs in PBMCs of CHC may act as significant risk biomarkers for the development of CHC.

Distinctive intrahepatic characteristics of paediatric and adult pathogenesis of chronic hepatitis C infection

Mechanisms leading to liver damage in chronic hepatitis C (CHC) are being discussed, but both the immune system and the virus are involved. The aim of this study was to evaluate intrahepatic viral infection, apoptosis and portal and periportal/interface infiltrate in paediatric and adult patients to elucidate the pathogenesis of chronic hepatitis C. HCV-infected, activated caspase-3(+) and TUNEL(+) hepatocytes, as well as total, CD4(+), CD8(+), Foxp3(+) and CD20(+) lymphocytes infiltrating portal and periportal/interface tracts were evaluated in 27 paediatric and 32 adult liver samples by immunohistochemistry or immunofluorescence. The number of infected hepatocytes was higher in paediatric than in adult samples (p 0.0078). In children, they correlated with apoptotic hepatocytes (activated caspase-3(+) r = 0.74, p < 0.0001; TUNEL(+) r = 0.606, p 0.0017). Also, infected (p = 0.026) and apoptotic hepatocytes (p = 0.03) were associated with the severity of fibrosis. In adults, activated caspase-3(+) cell count was increased in severe hepatitis (p = 0.009). Total, CD4(+), CD8(+) and Foxp3(+) lymphocyte count was higher in adult samples (p < 0.05). Paediatric CD8(+) cells correlated with infected (r = 0.495, p 0.04) and TUNEL(+) hepatocytes (r = 0.474, p = 0.047), while adult ones correlated with activated caspase-3(+) hepatocytes (r = 0.387, p 0.04). In adults, CD8(+) was associated with hepatitis severity (p < 0.0001) and correlated with inflammatory activity (CD8(+) r = 0.639, p 0.0003). HCV, apoptosis and immune response proved to be involved in CHC pathogenesis of both paediatric and adult patients. However, liver injury in paediatric CHC would be largely associated with a viral cytopathic effect mediated by apoptosis, while in adults it would be mainly associated with an exacerbated immune response.

Reversal, maintenance or progression: what happens to the liver after a virologic cure of hepatitis C?

A sustained virological response (SVR) from HCV (synonymous with virological cure) leads to decreased mortality, morbidity and improved quality of life, as well as a reduced incidence of liver disease progression, including liver failure, cirrhosis and hepatocellular carcinoma. Large clinical trials comparing pre- and post-treatment liver biopsies demonstrate improvements in inflammation as well as fibrosis score following SVR. However, a small subset of patients display persistent hepatic inflammation and/or progress to cirrhosis despite SVR. In addition to conferring a risk of fibrosis progression, advanced fibrosis pre-treatment is a major risk factor for post-SVR hepatocellular carcinoma. In this review, we discuss the mechanisms of fibrosis regression uncovered using experimental fibrosis models and highlight potential mechanisms in those few patients with fibrosis progression despite SVR. We also introduce current concepts of fibrosis-dependent tumorigenesis post-SVR in patients with advanced disease. This article forms part of a symposium in Antiviral Research on "Hepatitis C: next steps toward global eradication."

Monocyte activation by interferon α is associated with failure to achieve a sustained virologic response after treatment for hepatitis C virus infection

BACKGROUND

Interferon α (IFN-α) and ribavirin can induce a sustained virologic response (SVR) in some but not all hepatitis C virus (HCV)-infected patients. The mechanism of effective treatment is unclear. One possibility is that IFN-α differentially improves the functional capacity of classic myeloid dendritic cells (mDCs) by altering expression of surface molecules or cytokines. Others have proposed that antigen-presenting cell activation could be paradoxically detrimental during HCV infection because of the production by monocytes of substances inhibitory or toxic to plasmacytoid dendritic cells.

METHODS

We examined responses to in vitro IFN-α treatment of peripheral blood leukocyte samples from a retrospective treatment cohort of nearly 200 HCV-seropositive patients who had undergone antiviral therapy with ribavirin and pegylated IFN. We analyzed the variable responses of antigen-presenting cell subsets to drug.

RESULTS

We found that patients achieving SVR were no more likely to have robust mDC activation in response to IFN-α than those who did not achieve SVR. Rather, patients achieving SVR were distinguished by restrained monocyte activation in the presence of IFN-α, a factor that was second in importance only to IL28B genotype in its association with SVR.

CONCLUSIONS

These results suggest that interindividual variability in the response of monocytes to IFN-α is an important determinant of treatment success with IFN-α-based regimens.

Emerging concepts in immunity to hepatitis C virus infection

Since the discovery of hepatitis C virus (HCV) by molecular cloning almost a quarter of a century ago, unprecedented at the time because the virus had never been grown in cell culture or detected serologically, there have been impressive strides in many facets of our understanding of the natural history of the disease, the viral life cycle, the pathogenesis, and antiviral therapy. It is apparent that the virus has developed multiple strategies to evade immune surveillance and eradication. This Review covers what we currently understand of the temporal and spatial immunological changes within the human innate and adaptive host immune responses that ultimately determine the outcomes of HCV infection.

Natural killer cells: multifaceted players with key roles in hepatitis C immunity

Natural killer cells (NKs) are involved in every stage of hepatitis C viral (HCV) infection, from protection against HCV acquisition and resolution in the acute phase to treatment-induced clearance. In addition to their direct antiviral actions, NKs are involved in the induction and priming of appropriate downstream T-cell responses. In the setting of chronic HCV, overall NK cell levels are decreased, subset distribution is altered, and changes in NK receptor (NKR) expression have been demonstrated, although the contribution of individual NKRs to viral clearance or persistence remains to be clarified. Enhanced NK cell cytotoxicity accompanied by insufficient interferon-γ production may promote liver damage in the setting of chronic infection. Treatment-induced clearance is associated with activation of NK cells, and it will be of interest to monitor NK cell responses to triple therapy. Activated NK cells also have anti-fibrotic properties, and the same hepatic NK cell populations that are actively involved in control of HCV may also be involved in control of HCV-associated liver damage. We still have much to learn, in particular: how do liver-derived NKs influence the outcome of HCV infection? Do NK receptors recognize HCV-specific components? And, are HCV-specific memory NK populations generated?

Association of hepatitis C with markers of hemostasis in HIV-infected and uninfected women in the women's interagency HIV study (WIHS)

BACKGROUND

Coinfection with HIV and hepatitis C virus (HCV) is common. HIV infection and treatment are associated with hypercoagulability; thrombosis in HCV is underinvestigated. Proposed markers of hemostasis in HIV include higher D-dimer, Factor VIII%, and plasminogen activator inhibitor-1 (PAI-1) antigen and lower total Protein S% (TPS) but have not been examined in HCV. We assessed the independent association of HCV with these 4 measures of hemostasis in a multicenter, prospective study of HIV: the Women's Interagency HIV Study.

METHODS

We randomly selected 450 HCV-infected (anti-HCV+ with detectable plasma HCV RNA) and 450 HCV-uninfected (anti-HCV-) women. HCV was the main exposure of interest in regression models.

RESULTS

Four hundred forty-three HCV+ and 425 HCV- women were included. HCV+ women had higher Factor VIII% (124.4% ± 3.9% vs. 101.8% ± 3.7%, P < 0.001) and lower TPS (75.7% ± 1.1% vs. 84.3% ± 1.1%, <0.001) than HCV- women, independent of HIV infection and viral load; there was little difference in PAI-1 or log10 D-dimer. After adjustment for confounders, these inferences remained. HIV infection was independently associated with higher Factor VIII% and log10 D-dimer and lower TPS.

CONCLUSIONS

HCV was independently associated with higher Factor VIII% and lower TPS consistent with hypercoagulability. Higher Factor VIII% and D-dimer and lower TPS were also strongly associated with HIV infection and levels of HIV viremia, independent of HCV infection. Further investigation is needed to determine if there is increased thrombotic risk from HCV. Studies examining hemostasis markers in HIV infection must also assess the contribution of HCV infection.

Ex vivo analysis of resident hepatic pro-inflammatory CD1d-reactive T cells and hepatocyte surface CD1d expression in hepatitis C

Hepatic CD1d-restricted and natural killer T-cell populations are heterogeneous. Classical 'type 1' α-galactosylceramide-reactive CD1d-restricted T cells express 'invariant' TCRα ('iNKT'). iNKT dominating rodent liver are implicated in inflammation, including in hepatitis models. Low levels of iNKT are detected in human liver, decreased in subjects with chronic hepatitis C (CHC). However, high levels of human hepatic CD161(±) CD56(±) noninvariant pro-inflammatory CD1d-restricted 'type 2' T cells have been identified in vitro. Unlike rodents, healthy human hepatocytes only express trace and intracellular CD1d. Total hepatic CD1d appears to be increased in CHC and primary biliary cirrhosis. Direct ex vivo analysis of human intrahepatic lymphocytes (IHL), including matched ex vivo versus in vitro expanded IHL, demonstrated detectable noninvariant CD1d reactivity in substantial proportions of HCV-positive livers and significant fractions of HCV-negative livers. However, α-galactosylceramide-reactive iNKT were detected only relatively rarely. Liver CD1d-restricted IHL produced IFNγ, variable levels of IL-10 and modest levels of Th2 cytokines IL-4 and IL-13 ex vivo. In a novel FACS assay, a major fraction (10-20%) of hepatic T cells rapidly produced IFNγ and up-regulated activation marker CD69 in response to CD1d. As previously only shown with murine iNKT, noninvariant human CD1d-specific responses were also augmented by IL-12. Interestingly, CD1d was found selectively expressed on the surface of hepatocytes in CHC, but not those CHC subjects with history of alcohol usage or resolved CHC. In contrast to hepatic iNKT, noninvariant IFNγ-producing type 2 CD1d-reactive NKT cells are commonly detected in CHC, together with cognate ligand CD1d, implicating them in CHC liver damage.

Serum apoptosis markers related to liver damage in chronic hepatitis C: sFas as a marker of advanced fibrosis in children and adults while M30 of severe steatosis only in children

Background

Liver biopsy represents the gold standard for evaluating damage and progression in patients with chronic hepatitis C (CHC); however, developing noninvasive tests that can predict liver injury represents a growing medical need. Considering that hepatocyte apoptosis plays a role in CHC pathogenesis; the aim of our study was to evaluate the presence of different apoptosis markers that correlate with liver injury in a cohort of pediatric and adult patients with CHC.

Methods

Liver biopsies and concomitant serum samples from 22 pediatric and 22 adult patients with CHC were analyzed. Histological parameters were evaluated. In serum samples soluble Fas (sFas), caspase activity and caspase-generated neoepitope of the CK-18 proteolytic fragment (M30) were measured.

Results

sFas was associated with fibrosis severity in pediatric (significant fibrosis p = 0.03, advanced fibrosis p = 0.01) and adult patients (advanced fibrosis p = 0.02). M30 levels were elevated in pediatric patients with severe steatosis (p = 0.01) while in adults no relation with any histological variable was observed. Caspase activity levels were higher in pediatric samples with significant fibrosis (p = 0.03) and they were associated with hepatitis severity (p = 0.04) in adult patients. The diagnostic accuracy evaluation demonstrated only a good performance for sFas to evaluate advanced fibrosis both in children (AUROC: 0.812) and adults (AUROC: 0.800) as well as for M30 to determine steatosis severity in children (AUROC: 0.833).

Conclusions

Serum sFas could be considered a possible marker of advanced fibrosis both in pediatric and adult patient with CHC as well as M30 might be a good predictor of steatosis severity in children.

Innate immune responses in hepatitis C virus infection

Hepatitis C virus (HCV) is a major causative agent of chronic hepatitis and hepatocellular carcinoma worldwide and thus poses a significant public health threat. A hallmark of HCV infection is the extraordinary ability of the virus to persist in a majority of infected people. Innate immune responses represent the front line of defense of the human body against HCV immediately after infection. They also play a crucial role in orchestrating subsequent HCV-specific adaptive immunity that is pivotal for viral clearance. Accumulating evidence suggests that the host has evolved multifaceted innate immune mechanisms to sense HCV infection and elicit defense responses, while HCV has developed elaborate strategies to circumvent many of these. Defining the interplay of HCV with host innate immunity reveals mechanistic insights into hepatitis C pathogenesis and informs approaches to therapy. In this review, we summarize recent advances in understanding innate immune responses to HCV infection, focusing on induction and effector mechanisms of the interferon antiviral response as well as the evasion strategies of HCV.

Development of persistent HCV genotype 3a infection cell culture model in huh-7 cell

Background

Hepatitis C virus (HCV) is one of the major health concerns globally, with genotype 3a as the most prevalent in Pakistan. Lack of efficient HCV genotype 3a small animal models as well as genomic replicons has hampered the complete understanding of its life cycle, pathogenesis and therapeutic options. In this study we aimed to develop a persistent HCV genotype 3a infectious cell culture model.

Methods

We inoculated Huh-7 cells with HCV genotype 3a serum. Cells and media supernatant were collected at different time periods up to 40^th day post infection. Culture media supernatant was also collected to find out its ability to infect naive Huh-7 cells.

Results

HCV replication was confirmed at both RNA and protein level through Real Time RCR and western blot using HCV core as marker. In order to validate the persistence of our model for HCV genotype 3a replication we inhibited the HCV replication through core specific siRNAs. The HCV RNA was detected intracellularly from the day one post infection up till 40^th day, while HCV core protein was detected from the second day up to 40^th day consistently. In culture media supernatant HCV RNA was also actively detected conferring its ability to infect the naive Huh-7 cells. Furthermore, core specific siRNA showed significant inhibition at 24^th hour post transfection both at RNA and protein level with progressive increase in the expression of core gene after 3^rd day. It clearly depicts that the Huh-7 successfully retained the HCV replication after degradation of siRNA.

Conclusion

Finally, we report that our persistent infection cell culture model consistently replicate HCV genotype 3a for more than 1 month.

HCV entry receptors as potential targets for siRNA-based inhibition of HCV

Background

Hepatitis C virus (HCV) is a major health concern with almost 3% of the world's population (350 million individuals) and 10% of the Pakistani population chronically infected with this viral pathogen. The current therapy of interferon-α and ribavirin against HCV has limited efficiency, so alternative options are desperately needed. RNA interference (RNAi), which results in a sequence-specific degradation of HCV RNA has potential as a powerful alternative molecular therapeutic approach. Concerning viral entry, the HCV structural gene E2 is mainly involved in virus attachment to the host cell surface receptors i.e., CD81 tetraspanin, scavenger receptor class B type 1 (SR-B1), low density lipoprotein receptor (LDLR) and claudin1 (CLDN1).

Results

In this report, we studied the relationship of the HCV receptors CD81, LDL, CLDN1 and SR-B1to HCV infection. The potential of siRNAs to inhibit HCV-3a replication in serum-infected Huh-7 cells was demonstrated by treatment with siRNAs against HCV receptors, which resulted in a significant decrease in HCV viral copy number.

Conclusions

Our data clearly demonstrate that the RNAi-mediated silencing of HCV receptors is among the first of its type for the development of an effective siRNA-based therapeutic option against HCV-3a. These findings will shed further light on the possible role of receptors in inhibition of HCV-3a viral titre through siRNA mediated silencing.

Characterization of HCV interactions with Toll-like receptors and RIG-I in liver cells

BACKGROUND AND AIM

The aim of this study was to examine the mechanisms of IFN induction and viral escape. In order to accomplish the goal we compared our new hepatoma cell line LH86, which has intact TLR3 and RIG-I expression and responds to HCV by inducing IFN, with Huh7.5 cells which lack those features.

METHODS

The initial interaction of LH86 cells, Huh7.5 cells or their transfected counter parts (LH86 siRIG-I, siTLR3 or siTLR7 and Huh7.5 RIG-I, TLR3 or TLR7) after infection with HCV (strain JFH-1) was studied by measuring the expression levels of IFNβ, TRAIL, DR4, DR5 and their correlation to viral replication.

RESULTS

HCV replicating RNA induces IFN in LH86 cells. The IFN induction system is functional in LH86, and the expression of the RIG-I and TLR3 in LH86 is comparable to the primary hepatocytes. Both proteins appear to play important roles in suppression of viral replication. We found that innate immunity against HCV is associated with the induction of apoptosis by RIG-I through the TRAIL pathway and the establishment of an antiviral state by TLR3. HCV envelope proteins interfere with the expression of TLR3 and RIG-I.

CONCLUSION

These findings correlate with the lower expression level of PRRs in HCV chronic patients and highlight the importance of the PRRs in the initial interaction of the virus and its host cells. This work represents a novel mechanism of viral pathogenesis for HCV and demonstrates the role of PRRs in viral infection.