Tumor necrosis factor alpha gene expression and the response to interferon in chronic hepatitis C

TNF-alpha inhibitors and ustekinumab for the treatment of psoriasis: therapeutic utility in the era of IL-17 and IL-23 inhibitors

Psoriasis is a chronic inflammatory condition for which eleven FDA-approved biologic therapies are approved. Over the past decade, studies have documented the higher efficacy of IL-17 and IL-23 inhibitors for the treatment of psoriasis compared to the TNF-alpha inhibitors and ustekinumab, an IL-12/23 inhibitor. Despite this, there remains an important role for the use of TNF-alpha inhibitors and ustekinumab in the treatment of psoriasis. Here, we review how considerations of infection and malignancy risk, patient demographics, treatment resistance, and co-morbidities may make certain TNF-alpha inhibitors or ustekinumab an excellent choice for therapy in particular patient subgroups.

Inflammatory and cardiovascular diseases biomarkers in chronic hepatitis C virus infection: A review

Hepatitis C virus (HCV) infects 180 million people worldwide and over 4 million people in the United States. HCV infection is a major cause of chronic liver disease and is recognized as a risk factor for clinical cardiovascular disease (CVD). Many studies have shown increased prevalence of cardiac and inflammatory biomarkers in patients with chronic HCV infection (CHC), and though these markers may be used to risk stratify people for cardiac disease in the general population their role in the HCV population is unknown. Patients with CHC have elevated cardiac and inflammatory biomarkers compared to noninfected controls which may play a role in CVD risk stratification. We undertook a systematic review of inflammatory and cardiac biomarkers in people with HCV infection with a focus on the effect of CHC on serum levels of these markers and their utility as predictors of CVD in this population. Medline, EMBASE, and Cochrane databases were searched for relevant articles until June 2019. A total of 2430 results were reviewed with 115 studies included. Our review revealed that HCV infection significantly alters serum levels of markers of inflammation, endothelial function, and cardiac dysfunction prior to HCV treatment, and some of which may change in response to HCV therapy. Current risk stratification tools for development of CVD in the general population may not account for the increased inflammatory markers that appear to be elevated among HCV‐infected patients contributing to increased CVD risk.

Complexity on modulation of NF-κB pathways by hepatitis B and C: A double-edged sword in hepatocarcinogenesis

Nuclear factor-κB (NF-κB), a family of master regulated dimeric transcription factors, signaling transduction pathways are active players in the cell signaling that control vital cellular processes, including cell growth, proliferation, differentiation, apoptosis, morphogenesis, angiogenesis, and immune responses. Nevertheless, aberrant regulation of the NF-κB signaling pathways has been associated with a significant number of human cancers. In fact, NF-κB acts as a double-edged sword in the vital cellular processes and carcinogenesis. This review provides an overview on the modulation of the NF-κB signaling pathways by proteins of hepatitis B and C viruses. One of the major NF-κB events that are modulated by these viruses is the induction of hepatocellular carcinoma. Given the central function of NF-κB in carcinogenesis, it has turned out to be a considerable therapeutic target for cancer therapy.

Changes in inflammatory biomarkers in HCV-infected patients undergoing direct acting antiviral-containing regimens with or without interferon

Background and aims

Increased levels of chemokine interferon-gamma (IFN-γ)-inducible protein-10 (CXCL10), soluble CD163 (sCD163) and soluble CD14 (sCD14) have been reported in HCV infection. The aim of this study was to compare, sCD163 and sCD14 levels in HCV-infected patients undergoing direct acting antiviral (DAA)-containing regimens with or without interferon (IFN).

Methods

sCD163, sCD14 and CXCL10 were longitudinally measured by ELISA in 159 plasma samples from 25 HCV-infected patients undergoing IFN-based treatment plus telaprevir or boceprevir and 28 HCV infected subjects treated with DAA IFN-free regimens. Twenty-five healthy donors (HD) were included as controls.

Results

At baseline CXCL10, sCD163 and sCD14 levels were higher in HCV-infected patients than in HD. CXCL10 and sCD163 levels were significantly decreased in responder (R) patients who achieved sustained virological response (SVR), with both IFN-based and IFN-free regimens, while they were persistently elevated in non-responders (NR) patients who stopped IFN-based treatments because of failure or adverse events. Conversely, sCD14 levels were apparently unchanged during therapy, but at the end of treatment the levels reached normal ranges. Comparing the two regimens, the extent of CXCL10 reduction was more pronounced in patients undergoing DAA IFN-free therapies, whereas sCD163 and sCD14 reduction was similar in the two groups.

Interestingly, only in IFN-based regimens baseline sCD163 levels were significantly higher in NR than in R patients, while in the IFN-free treatment group also patients with high sCD163 plasma levels obtained SVR. At the end of therapy, even if the biomarkers were largely decreased, their levels remained significantly higher compared to HD. Only in the early fibrosis stages, sCD163 values tended to normalize.

Conclusions

These results indicate that IFN-free regimens including newer DAA induce an early and marked decrease in circulating inflammatory biomarkers. However, the full normalization of biomarkers was not obtained, especially in patients with advanced fibrosis, thus underlying the need for a treatment in the early stages of HCV infection.

Immune response in human chromoblastomycosis and eumycetoma - focusing on human interleukin-17A, interferon-gamma, tumour necrosis factor-alpha, interleukin-1 beta and human beta-defensin-2

Knowledge regarding host immune response to chromoblastomycosis and eumycetoma is limited, particularly concerning cytokines and antimicrobial peptides production. This was a retrospective study of 12 paraffin-embedded tissue samples from patients diagnosed with chromoblastomycosis or eumycetoma from histological findings and tissue culture. DNA extraction and polymerase chain reaction (PCR) from tissues were done to evaluate human interleukin-17A (IL-17A), interferon-gamma (IFN-γ), tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and human beta-defensin-2 (HBD-2) expressions. Human beta-actin primer was used for confirming DNA detection, and DNA extracted from psoriasis lesional skin samples was used as positive controls. The twelve paraffin-embedded sections used in this study consisted of five chromoblastomycosis and seven eumycetoma tissues. All PCR reactions showed beta-actin band at 51 bp in all clinical specimens, confirming adequate DNA levels in each reaction. As positive control, the psoriasis skin samples revealed bands for IL-17A at 174 bp, IFN-γ at 273 bp, TNF-α at 360 bp, IL-1β at 276 bp and HBD-2 at 255 bp. For the chromoblastomycosis and eumycetoma tissues, PCR analyses showed IL-17A band at 174 bp in two eumycetoma tissues and HBD-2 band at 255 bp in a chromoblastomycosis tissue. This study demonstrated IL-17A expression in human eumycetoma and HBD-2 expression in human chromoblastomycosis for the first time. However, their role in immune response remains to be elucidated.

Lipopolysaccharide and Tumor Necrosis Factor Alpha Inhibit Interferon Signaling in Hepatocytes by Increasing Ubiquitin-Like Protease 18 (USP18) Expression

Inflammation may be maladaptive to the control of viral infection when it impairs interferon (IFN) responses, enhancing viral replication and spread. Dysregulated immunity as a result of inappropriate innate inflammatory responses is a hallmark of chronic viral infections such as, hepatitis B virus and hepatitis C virus (HCV). Previous studies from our laboratory have shown that expression of an IFN-stimulated gene (ISG), ubiquitin-like protease (USP)18 is upregulated in chronic HCV infection, leading to impaired hepatocyte responses to IFN-α. We examined the ability of inflammatory stimuli, including tumor necrosis factor alpha (TNF-α), lipopolysaccharide (LPS), interleukin-6 (IL-6) and IL-10 to upregulate hepatocyte USP18 expression and blunt the IFN-α response. Human hepatoma cells and primary murine hepatocytes were treated with TNF-α/LPS/IL-6/IL-10 and USP18, phosphorylated (p)-STAT1 and myxovirus (influenza virus) resistance 1 (Mx1) expression was determined. Treatment of Huh7.5 cells and primary murine hepatocytes with LPS and TNF-α, but not IL-6 or IL-10, led to upregulated USP18 expression and induced an IFN-α refractory state, which was reversed by USP18 knockdown. Liver inflammation was induced in vivo using a murine model of hepatic ischemia/reperfusion injury. Hepatic ischemia/reperfusion injury led to an induction of USP18 expression in liver tissue and promotion of lymphocytic choriomeningitis replication. These data demonstrate that certain inflammatory stimuli (TNF-α and LPS) but not others (IL-6 and IL-10) target USP18 expression and thus inhibit IFN signaling. These findings represent a new paradigm for how inflammation alters hepatic innate immune responses, with USP18 representing a potential target for intervention in various inflammatory states.

IMPORTANCE Inflammation may prevent the control of viral infection when it impairs the innate immune response, enhancing viral replication and spread. Blunted immunity as a result of inappropriate innate inflammatory responses is a common characteristic of chronic viral infections. Previous studies have shown that expression of certain interferon-stimulated genes is upregulated in chronic HCV infection, leading to impaired hepatocyte responses. In this study, we show that multiple inflammatory stimuli can modulate interferon stimulated gene expression and thus inhibit hepatocyte interferon signaling via USP18 induction. These findings represent a new paradigm for how inflammation alters hepatic innate immune responses, with the induction of USP18 representing a potential target for intervention in various inflammatory states.

Tumour necrosis factor -308 and -238 promoter polymorphisms are predictors of a null virological response in the treatment of Brazilian hepatitis C patients

Certain host single nucleotide polymorphisms (SNPs) affect the likelihood of a sustained virological response (SVR) to treatment in subjects infected with hepatitis C virus (HCV). SNPs in the promoters of interleukin (IL)-10 (-1082 A/G, rs1800896), myxovirus resistance protein 1 (-123 C/A, rs17000900 and -88 G/T, rs2071430) and tumour necrosis factor (TNF) (-308 G/A, rs1800629 and -238 G/A, rs361525) genes and the outcome of PEGylated α-interferon plus ribavirin therapy were investigated. This analysis was performed in 114 Brazilian, HCV genotype 1-infected patients who had a SVR and in 85 non-responders and 64 relapsers. A significantly increased risk of having a null virological response was observed in patients carrying at least one A allele at positions -308 [odds ratios (OR) = 2.58, 95% confidence intervals (CI) = 1.44-4.63, p = 0.001] or -238 (OR = 7.33, 95% CI = 3.59-14.93, p < 0.001) in the TNF promoter. The risk of relapsing was also elevated (-308: OR = 2.87, 95% CI = 1.51-5.44, p = 0.001; -238: OR = 4.20, 95% CI = 1.93-9.10, p < 0.001). Multiple logistic regression of TNF diplotypes showed that patients with at least two copies of the A allele had an even higher risk of having a null virological response (OR = 16.43, 95% CI = 5.70-47.34, p < 0.001) or relapsing (OR = 6.71, 95% CI = 2.18-20.66, p = 0.001). No statistically significant association was found between the other SNPs under study and anti-HCV therapy response.

Safety and efficacy of anti-tumor necrosis factors α in patients with psoriasis and chronic hepatitis C

Up to date, in literature, it is still debated the role of anti-tumor necrosis factors (TNF)-α treatments in hepatitis C virus (HCV) patients. TNF-α performs a lot of functions, it is an important pro-inflammatory cytokine and it is involved in the host’s immunity. Since TNF-α is implicated in the apoptotic signaling pathway of hepatocytes infected by HCV, anti TNF-α therapy may increase the risk of viral replication or their reactivation. However the treatment of anti TNF-α could have a healthful role because TNF-α appears to be engaged in the pathogenesis of liver fibrosis, inducing apoptotic pathways. We describe the case of a patient with plaque-type psoriasis and concomitant chronic HCV, who was treated successfully with anti-TNF agents simultaneously to cyclosporine without sign of reactivation of HCV and increase of liver enzymes. Our personal experience shows that anti-TNF-α agents are not only effective but also safe. Furthermore the combination therapy of cyclosporine and anti-TNF-α appears to be well-tolerated and able to reduce the amount of liver enzymes as well as HCV-viral-load. However systematic, large-scale studies with long follow-ups will be needed to confirm our results, in association with close liver function monitoring.

Plasma Levels of Matrix Metalloproteinase (MMP)-2, MMP-9 and Tumor Necrosis Factor-α in Chronic Hepatitis C Virus Patients

BACKGROUND

In chronic HCV infection, pathological accumulation of the extracellular matrix is the main feature of liver fibrosis; that indicates the imbalanced rate of increased matrix synthesis to decreased breakdown of connective tissue proteins. Matrix metalloproteinases (MMPs) play a crucial role in remodeling of extracellular matrix. It is known that expression of MMPs is regulated by Tumor necrosis factor (TNF)-α. Also, levels of TNF-α in liver and serum are increased in chronic HCV patient. Accordingly, this study aimed to correlate the plasma levels of MMP-2, MMP-9 and TNF-α in chronic HCV patients with the pathogenesis of the liver.

METHODS

The current study was conducted on 15 fibrotic liver cases with detectable HCV RNA, 10 HCV cirrhotic liver cases, and 15 control subjects of matched age and sex. Plasma MMP-2, MMP-9 and TNF-α were measured by ELISA.

RESULTS

Data revealed that the MMP2, MMP9 and TNF-α levels showed a significant elevation in chronic HCV patients compared to control group (p= 0.001). But, no significant correlation was observed in levels of MMP-2, MMP-9, and TNF-α between fibrotic and cirrhotic cases.

CONCLUSIONS

MMP-2, MMP-9 and TNF-α showed high reproducibility to differentiate chronic HCV patients from control group. On the contrary, MMP-2, MMP-9 and TNF-α were not able to differentiate fibrotic from cirrhotic liver cases. Thus, MMP-2, MMP-9 and TNF-α could not be correlated with the progression of liver disease. Rather they could be used as prognostic markers of liver fibrosis.

MCPIP1 suppresses hepatitis C virus replication and negatively regulates virus-induced proinflammatory cytokine responses

Human MCP-1-induced protein 1 (MCPIP1, also known as ZC3H12A and Regnase-1) plays important roles in negatively regulating the cellular inflammatory response. Recently, we found that as an RNase, MCPIP1 has broad-spectrum antiviral effects by targeting viral RNA. In this study, we demonstrated that MCPIP1 expression was induced by hepatitis C virus (HCV) infection in Huh7.5 hepatoma cells. MCPIP1 expression was higher in liver tissue from patients with chronic HCV infection compared with those without chronic HCV infection. Knockdown of MCPIP1 increased HCV replication and HCV-mediated expression of proinflammatory cytokines, such as TNF-α, IL-6, and MCP-1. However, overexpression of MCPIP1 significantly inhibited HCV replication and HCV-mediated expression of proinflammatory cytokines. Various mutants of functional domains of MCPIP1 showed disruption of the RNA binding and oligomerization abilities, as well as RNase activity, but not deubiquitinase activity, which impaired the inhibitory activity against HCV replication. On immunocytochemistry, MCPIP1 colocalized with HCV RNA. Use of a replication-defective HCV John Cunningham 1/AAG mutant and in vitro RNA cleavage assay demonstrated that MCPIP1 could directly degrade HCV RNA. MCPIP1 may suppress HCV replication and HCV-mediated proinflammatory responses with infection, which might contribute to the regulation of host defense against the infection and virus-induced inflammation.

Role of p38 MAP Kinase Signal Transduction in Solid Tumors

Mitogen-activated protein kinases (MAPKs) mediate a wide variety of cellular behaviors in response to extracellular stimuli. One of the main subgroups, the p38 MAP kinases, has been implicated in a wide range of complex biologic processes, such as cell proliferation, cell differentiation, cell death, cell migration, and invasion. Dysregulation of p38 MAPK levels in patients are associated with advanced stages and short survival in cancer patients (e.g., prostate, breast, bladder, liver, and lung cancer). p38 MAPK plays a dual role as a regulator of cell death, and it can either mediate cell survival or cell death depending not only on the type of stimulus but also in a cell type specific manner. In addition to modulating cell survival, an essential role of p38 MAPK in modulation of cell migration and invasion offers a distinct opportunity to target this pathway with respect to tumor metastasis. The specific function of p38 MAPK appears to depend not only on the cell type but also on the stimuli and/or the isoform that is activated. p38 MAPK signaling pathway is activated in response to diverse stimuli and mediates its function by components downstream of p38. Extrapolation of the knowledge gained from laboratory findings is essential to address the clinical significance of p38 MAPK signaling pathways. The goal of this review is to provide an overview on recent progress made in defining the functions of p38 MAPK pathways with respect to solid tumor biology and generate testable hypothesis with respect to the role of p38 MAPK as an attractive target for intervention of solid tumors.

Molecular mechanisms of liver fibrosis in HIV/HCV coinfection

Chronic hepatitis C virus (HCV) infection is an important cause of morbidity and mortality in people coinfected with human immunodeficiency virus (HIV). Several studies have shown that HIV infection promotes accelerated HCV hepatic fibrosis progression, even with HIV replication under full antiretroviral control. The pathogenesis of accelerated hepatic fibrosis among HIV/HCV coinfected individuals is complex and multifactorial. The most relevant mechanisms involved include direct viral effects, immune/cytokine dysregulation, altered levels of matrix metalloproteinases and fibrosis biomarkers, increased oxidative stress and hepatocyte apoptosis, HIV-associated gut depletion of CD4 cells, and microbial translocation. In addition, metabolic alterations, heavy alcohol use, as well drug use, may have a potential role in liver disease progression. Understanding the pathophysiology and regulation of liver fibrosis in HIV/HCV co-infection may lead to the development of therapeutic strategies for the management of all patients with ongoing liver disease. In this review, we therefore discuss the evidence and potential molecular mechanisms involved in the accelerated liver fibrosis seen in patients coinfected with HIV and HCV.

Impact of IL-10 (-1082) promoter-single nucleotide polymorphism on the outcome of hepatitis C virus genotype 4 infection

Immunoregulatory cytokines may influence the hepatitis C virus (HCV) infection outcome. This study aimed to determine the genotypic and allelic frequencies of the interleukin (IL)-10 (-1082) G/A polymorphism, and its association with chronicity or resolution of HCV genotype 4 infection in Egypt. The frequencies of different dimorphic polymorphisms based on single nucleotide substitution in chronic HCV patients (50) and resolved HCV patients (50) were: IL-10 (-1082) G/G 22 (44%) and 18 (36%), G/A 19 (38%) and 24 (48%), and A/A 9 (18%), and 8 (16%), respectively. In the sustained virologic response (SVR) (36) and spontaneously resolved subjects (14) groups, the frequencies were: IL-10 (-1082) G/G 11 (30.6%) and 7 (50%) G/A 18 (50%) and 6 (42.9%), A/A 7 (19.4%) and 1 (7.1%), respectively. An association between male gender and chronic hepatitis C outcome (P value 0.041) was found. However, no significant gender difference was found when we compared females versus males with elevated alanine transaminase (ALT) levels in the chronic HCV patient group (P value = 1).

CONCLUSION

No significant difference in the frequency of IL-10 single nucleotide polymorphism (SNP) at position 1082 was found between chronic and resolved HCV subjects.

Single-dose infliximab in hepatitis C genotype 1 treatment-naive patients with high serum tumour necrosis factor-alpha does not influence the efficacy of pegylated interferon alpha-2b/ribavirin therapy

BACKGROUND

Serum tumour necrosis factor-alpha (TNF-α) levels correlate negatively with hepatitis C virus (HCV) antiviral response.

OBJECTIVES

To test the hypothesis that a single infliximab induction dose would positively influence on-treatment virological response and sustained virological response (SVR).

METHODS

The present study was a phase IIIB, randomized, prospective, open-label pilot trial conducted at eight Canadian sites. Treatment-naive HCV genotype 1-infected patients 18 to 65 years of age with high serum TNF-α values (>300 pg⁄mL) were randomly assigned to receive a single pretreatment induction infliximab infusion (5 mg⁄kg) seven days before antiviral therapy (arm A) or no pretreatment (arm B). All patients received pegylated interferon α2b (1.5 μg⁄kg⁄week) plus weight-based ribavirin (800 mg⁄day to 1400 mg⁄day) for up to 48 weeks.

RESULTS

Eighty-five patients (arm A [n=41], arm B [n=44]; 70% male) received pegylated interferon α2b. The mean age (48.1 years), race (81% white) and METAVIR fibrosis stage (F0-2 = 79%, F3-4 = 21%) were similar between groups. Infliximab was well tolerated without attributable severe adverse events; 56.5% completed the study (arm A [n=21], arm B [n=27]). Most discontinuations were due to virological failure at weeks 12 (n=20 [23.5%]) and 24 (n=7 [8.2%]) and did not differ according to group. Numerically lower proportions of infliximab recipients achieved rapid virological response (19.5% versus 36.4%), complete early virological response (43.9% versus 59.1%) and SVR (34.1% versus 52.3%). However, between-group differences did not reach statistical significance. No differences in adverse event profile or laboratory measures were noted.

CONCLUSION

A single infliximab dose before pegylated-interferon α2b and ribavirin therapy did not result in greater viral decline during the first 12 weeks of HCV therapy or improved SVR.

A Possible Role for TNF-α in Coordinating Inflammation and Angiogenesis in Chronic Liver Disease and Hepatocellular Carcinoma

BACKGROUND

Increasing evidence supports the hypothesis that chronic and persistent inflammation contributes to cancer development. However, the molecular mechanisms that lead to cancer in chronic inflammation and the role of angiogenesis in inflammation-associated cancer remain poorly understood.

METHODS

NINETY PATIENTS WERE ENROLLED: 30 cases of CHC without cirrhosis, 28 cases of CHC with liver cirrhosis, and 32 cases of HCC and hepatitis C virus infection. Ten wedge liver biopsies, taken during laparoscopic cholecystectomy, served as normal controls. Serum TNF-α levels were measured using the ELISA technique; in situ hybridization and immunohistochemical studies were used to detect hepatic levels of messenger RNA (mRNA) transcripts and mature protein, respectively, for both TNF-α and VEGF.

RESULTS

The highest hepatic expression of TNF-α was noticed in liver cirrhosis specimens compared to noncirrhotic CHC and HCC. Hepatic expression of VEGF and serum level of TNF-α revealed significant increases in the progression of the disease. Moreover, cases with higher grades of inflammation or stages of fibrosis showed significant increases in serum TNF-α and expression of TNF-α and VEGF. Expression of mRNA of both TNF-α and VEGF shows increasing expression with positive correlation to progression of viral hepatitis to cirrhosis with more positivity in cases developed HCC.

CONCLUSIONS

VEGF signaling could be one of the molecular signaling pathways involved in TNF-α induced angiogenesis which might pose an important link between inflammation and fibrosis in CHC and HCC development and progression. Moreover, serum inflammatory biomarkers can be used to monitor the disease progression.

The influence of anti-TNF therapy on the course of chronic hepatitis C virus infection in patients with inflammatory bowel disease

BACKGROUND

The immunosuppressive potential of anti-tumor necrosis factor (TNF) in exacerbating chronic hepatitis C virus (HCV) infection has been a major concern. We aim to critically analyze the impact of anti-TNF on the course of chronic HCV infection in patients with concurrent inflammatory bowel disease (IBD) and HCV infection.

MATERIALS AND METHODS

Patients with diagnosis of IBD and HCV were identified retrospectively through the University of Pennsylvania Health System electronic database. Data assessed included demographics, duration of IBD and HCV infection, HCV RNA levels, HCV genotype, liver histology, hepatic biochemical tests (HBT) and IBD disease activity index.

RESULTS

A total of 4,274 IBD and 3,523 HCV patients were identified from 10/1998 to 05/2010. Thirty-seven patients had concurrent HCV infection and IBD, of which 23 patients were eligible (61 % CD; 39 % UC). Five patients (22 %) received anti-TNF therapy (infliximab). Two patients received pegylated interferon and ribavirin (both were non-responders). Overall, three patients had clinical remission and one patient had clinical response to infliximab. When compared to baseline, one patient had HBT improvement, three patients remained stable and one patient had HBT elevation, which was likely due to progressive liver disease in view of HIV co-infection.

CONCLUSION

This represents the first critical analysis assessing the impact of anti-TNF therapy on the course of chronic HCV in IBD patients. Concurrent HCV infection in IBD patients is uncommon. Treatment of IBD with infliximab in HCV patients did not result in flares in hepatic biochemical tests while there was an improvement in the IBD disease activity score.

Phage Display Screening for Tumor Necrosis Factor- α -Binding Peptides: Detection of Inflammation in a Mouse Model of Hepatitis

TNF-α is one of the most abundant cytokines produced in many inflammatory and autoimmune conditions such as multiple sclerosis, chronic hepatitis C, or neurodegenerative diseases. These pathologies remain difficult to diagnose and consequently difficult to treat. The aim of this work is to offer a new diagnostic tool by seeking new molecular probes for medical imaging. The target-specific part of the probe consists here of heptameric peptides selected by the phage display technology for their affinity for TNF-α. Several affinity tests allowed isolating 2 peptides that showed the best binding capacity to TNF-α. Finally, the best peptide was synthesized in both linear and cyclic forms and tested on the histological sections of concanavalin-A-(ConA-)treated mice liver. In this well-known hepatitis mouse model, the best results were obtained with the cyclic form of peptide 2, which allowed for the staining of inflamed areas in the liver. The cyclic form of peptide 2 (2C) was, thus, covalently linked to iron oxide nanoparticles (magnetic resonance imaging (MRI) contrast agent) and tested in the ConA-induced hepatitis mouse model. The vectorized nanoparticles allowed for the detection of inflammation as well as of the free peptide. These ex vivo results suggest that phage display-selected peptides can direct imaging contrast agents to inflammatory areas.

Host factors determining the efficacy of hepatitis C treatment

Combination therapy with pegylated interferon and ribavirin is the standard of care (SOC) for the treatment of chronic hepatitis C (CHC). Treating CHC with SOC may show a sustained virological response (SVR) in approximately 50-70 % of genotype 1 CHC patients and an SVR in 70-90 % of genotype 2 CHC patients. The genotype, baseline viral load, and viral kinetics (i.e., rapid virologic response and early virologic response) can be used as predictors of response-guided therapy. Nonetheless, host factors, e.g. age, ethnicity, insulin resistance, and genetic variations, may also play important roles in the SVR in CHC patients treated with SOC. Recent genome-wide association studies have demonstrated that single-nucleotide polymorphisms near the interleukin 28B gene (IL28B) were associated with SVR to treatment with SOC in CHC patients. The IL28B polymorphisms may contribute to the viral kinetics during treatment. Asian people have favorable IL28B polymorphisms. This factor may at least partly explain the high eradication rate of hepatitis C by SOC in Asia. Combination therapy with direct-acting antivirals (DAAs) and SOC can increase the SVR rates both in treatment-naïve and treatment-experienced patients. Although the IL28B polymorphisms also affect the SVR of triple therapy with SOC and first-generation protease inhibitors, pilot studies have demonstrated that potent DAAs might overcome the influence of IL28B polymorphisms. Thus, the treatment of hepatitis C virus infection could be simplified in the near future.

Immunization with a recombinant vaccinia virus that encodes nonstructural proteins of the hepatitis C virus suppresses viral protein levels in mouse liver

Chronic hepatitis C, which is caused by infection with the hepatitis C virus (HCV), is a global health problem. Using a mouse model of hepatitis C, we examined the therapeutic effects of a recombinant vaccinia virus (rVV) that encodes an HCV protein. We generated immunocompetent mice that each expressed multiple HCV proteins via a Cre/loxP switching system and established several distinct attenuated rVV strains. The HCV core protein was expressed consistently in the liver after polyinosinic acid–polycytidylic acid injection, and these mice showed chronic hepatitis C-related pathological findings (hepatocyte abnormalities, accumulation of glycogen, steatosis), liver fibrosis, and hepatocellular carcinoma. Immunization with one rVV strain (rVV-N25), which encoded nonstructural HCV proteins, suppressed serum inflammatory cytokine levels and alleviated the symptoms of pathological chronic hepatitis C within 7 days after injection. Furthermore, HCV protein levels in liver tissue also decreased in a CD4 and CD8 T-cell-dependent manner. Consistent with these results, we showed that rVV-N25 immunization induced a robust CD8 T-cell immune response that was specific to the HCV nonstructural protein 2. We also demonstrated that the onset of chronic hepatitis in CN2-29^(+/−)/MxCre^(+/−) mice was mainly attributable to inflammatory cytokines, (tumor necrosis factor) TNF-α and (interleukin) IL-6. Thus, our generated mice model should be useful for further investigation of the immunological processes associated with persistent expression of HCV proteins because these mice had not developed immune tolerance to the HCV antigen. In addition, we propose that rVV-N25 could be developed as an effective therapeutic vaccine.

Association of chronic viral hepatitis B with insulin resistance

AIM: To investigate the relationship between chronic viral hepatitis B (CVHB) and insulin resistance (IR) in Korean adults.

METHODS: A total of 7880 adults (3851 men, 4029 women) who underwent a comprehensive medical examination were enrolled in this study. Subjects diagnosed with either diabetes mellitus, or any other disorder that could influence their insulin sensitivity, were rejected. Anthropometry, metabolic risk factors, hepatitis B surface antigen, hepatitis B surface antibody, hepatitis B core antibody, fasting plasma glucose and insulin were measured for all subjects. Homeostasis model assessment (HOMA), quantitative insulin check index (QUICKI), and Mf_fm index were used for determining insulin sensitivity. Each participant was categorized into a negative, recovery, or CVHB group. To compare variables between groups, a t-test and/or one-way analysis of variance were used. Partial correlation coefficients were computed to present the association between insulin resistance and other variables. Multiple logistic regression analysis was used to assess the independent association between CVHB and IR.

RESULTS: The mean age of men and women were 48.9 and 48.6 years, respectively. Subjects in the CVHB group had significantly higher waist circumference [(86.0 ± 7.7 cm vs 87.3 ± 7.8 cm, P = 0.004 in men), (78.3 ± 8.6 cm vs 80.5 ± 8.5 cm, P < 0.001 in women)], cystatin C [(0.96 ± 0.15 mg/dL vs 1.02 ± 0.22 mg/dL, P < 0.001 in men), (0.84 ± 0.15 mg/dL vs 0.90 ± 0.16 mg/dL, P < 0.001 in women)], fasting insulin [(5.47 ± 3.38 μU/mL vs 6.12 ± 4.62 μU/mL, P < 0.001 in men), (4.57 ± 2.82 μU/mL vs 5.06 ± 3.10 μU/mL, P < 0.001 in women)] and HOMA index [(1.24 ± 0.86 vs 1.43 ± 1.24, P < 0.001 in men), (1.02 ± 0.76 vs 1.13 ± 0.87, P = 0.033 in women)] compared to control group. The HOMA index revealed a positive correlation with body mass index (BMI) (r = 0.378, P < 0.001), waist circumference (r =0.356, P < 0.001), percent body fat (r = 0.296, P < 0.001), systolic blood pressure (r = 0.202, P < 0.001), total cholesterol (r = 0.134, P < 0.001), triglycerides (r = 0.292, P < 0.001), cystatin C (r = 0.069, P < 0.001) and uric acid (r = 0.142, P < 0.001). The QUICKI index revealed a negative correlation with BMI (r = -0.254, P < 0.001), waist circumference (r = 0-0.243, P < 0.001), percent body fat (r = -0.217, P < 0.001), systolic blood pressure (r = -0.132, P < 0.001), total cholesterol (r = -0.106, P < 0.001), triglycerides (r = -0.205, P < 0.001), cystatin C (r = -0.044, P < 0.001) and uric acid (r = -0.096, P < 0.001). For subjects identified with IR, the odds ratio of an accompanying diagnosis of chronic hepatitis B was 1.534 (95% CI: 1.158-2.031, HOMA index criteria) or 1.566 (95% CI: 1.124-2.182, QUICKI criteria) after adjustment for age, gender, BMI, and amount of alcohol consumption.

CONCLUSION: Our study demonstrates that CVHB is associated with IR. CVHB may need to be monitored for occurrence of IR and diabetes mellitus.

Increased microRNA-155 expression in the serum and peripheral monocytes in chronic HCV infection

Background

Hepatitis C Virus (HCV), a single stranded RNA virus, affects millions of people worldwide and leads to chronic infection characterized by chronic inflammation in the liver and in peripheral immune cells. Chronic liver inflammation leads to progressive liver damage. MicroRNAs (miRNA) regulate inflammation (miR-155, -146a and -125b) as well as hepatocyte function (miR-122).

Methods

Here we hypothesized that microRNAs are dysregulated in chronic HCV infection. We examined miRNAs in the circulation and in peripheral monocytes of patients with chronic HCV infection to evaluate if specific miRNA expression correlated with HCV infection.

Results

We found that monocytes from chronic HCV infected treatment-naïve (cHCV) but not treatment responder patients showed increased expression of miR-155, a positive regulator of TNFα, and had increased TNFα production compared to monocytes of normal controls. After LPS stimulation, miR-155 levels were higher in monocytes from cHCV patients compared to controls. MiR-125b, which has negative regulatory effects on inflammation, was decreased in cHCV monocytes compared to controls. Stimulation of normal monocytes with TLR4 and TLR8 ligands or HCV core, NS3 and NS5 recombinant proteins induced a robust increase in both miR-155 expression and TNFα production identifying potential mechanisms for in vivo induction of miR-155. Furthermore, we found increased serum miR-155 levels in HCV patients compared to controls. Serum miR-125b and miR-146a levels were also increased in HCV patients. Serum levels of miR-122 were elevated in cHCV patients and correlated with increased ALT and AST levels and serum miR-155 levels.

Conclusion

In conclusion, our novel data demonstrate that miR-155, a positive regulator of inflammation, is upregulated both in monocytes and in the serum of patients with chronic HCV infection. Our study suggests that HCV core, NS3, and NS5 proteins or TLR4 and TLR8 ligands can mediate increased miR-155 and TNFα production in chronic HCV infection. The positive correlation between serum miR-155 and miR-122 increase in cHCV may be an indicator of inflammation-induced hepatocyte damage.

Protein-tyrosine phosphatases are involved in interferon resistance associated with insulin resistance in HepG2 cells and obese mice

Insulin resistance is a risk factor for non-response to interferon/ribavirin therapy in patients with chronic hepatitis C. The aim of this study was to determine the role played by protein-tyrosine phosphatases (PTPs) in the absence of interferon-α (IFNα) response associated with insulin resistance. We induced insulin resistance by silencing IRS-2 or by treating HepG2 cells with tumor necrosis factor-α (TNFα) and analyzed insulin response by evaluating Akt phosphorylation and IFNα response by measuring Stat-1 tyrosine phosphorylation and 2',5'-oligoadenylate synthase and myxovirus resistance gene expression. The response to IFNα was also measured in insulin-resistant obese mice (high fat diet and ob/ob mice) untreated and treated with metformin. Silencing IRS-2 mRNA induces insulin resistance and inhibits IFNα response. Likewise, TNFα suppresses insulin and IFNα response. Treatment of cells with pervanadate and knocking down PTP-1B restores insulin and IFNα response. Both silencing IRS-2 and TNFα treatment increase PTP and PTP-1B activity. Metformin inhibits PTP and improves IFNα response in insulin-resistant cells. Insulin-resistant ob/ob mice have increased PTP-1B gene expression and activity in the liver and do not respond to IFNα administration. Treatment with metformin improves this response. In HepG2 cells, insulin resistance provokes IFNα resistance, which is associated with an increased PTP-1B activity in the liver. Inhibition of PTP-1B activity with pervanadate and metformin or knocking down PTP-1B reestablishes IFNα response. Likewise, metformin decreases PTP-1B activity and improves response to IFNα in insulin-resistant obese mice. The use of PTP-1B inhibitors may improve the response to IFNα/ribavirin therapy.

Incidence of CMV-HCV coinfection in renal transplant recipient

The authors report a case of a 47-year-old cytomegalovirus (CMV) immunoglobulin G (IgG) seropositive male patient with end stage renal disease who received a live renal transplant from a CMV IgG seropositive donor. Six months post-transplantation, the patient presented with reduced renal allograft function associated with fever, severe breathlessness, new onset jaundice and pancytopenia. His CMV DNA PCR came positive. Hepatitis C virus (HCV) RNA PCR also came positive (genotype I) though anti-HCV test performed before and after transplantation was negative. The patient was treated with oral valganciclovir and showed improvement of his clinical condition and was subsequently discharged under supervised therapy. However, the patient could not be treated for HCV because of risk of renal allograft rejection. The authors suggest oral valganciclovir for management of CMV infection and proper detection and eradication of HCV before renal transplantation to avoid future complications and prolongation of allograft survival.

Relationship between circulating interleukin-10 and histological features in patients with chronic C hepatitis

BACKGROUND AND OBJECTIVES

An imbalance in cytokine production may be involved in the pathogenesis of chronic C hepatitis. The aim of the study was to investigate circulating levels of interleukin-10 (IL-10) in a selected cohort of patients affected by chronic C hepatitis.

DESIGN AND SETTING

Retrospective study based on consecutive hepatitis C virus patients, affected by chronic active hepatitis, attending the general hospital of hepatology unit from June to September 2009

PATIENTS AND METHODS

A total of 49 patients with chronic C hepatitis and 20 healthy control subjects similar in gender and age were examined. Circulating IL-10 was assessed by ELISA commercial kit (R and D Systems) in all investigated subjects.

RESULTS

There was no significant difference in IL-10 values between controls and overall patients (P>.05). Nevertheless, among patients, subjects with more severe necroinflammation had higher values than others (P<.001). Moreover, a close relationship was found between IL-10 values and serum aspartate aminotransferase (r=0.61; P<.001).

CONCLUSIONS

These findings suggest that IL-10 may be a useful additional marker to assess necroinflammation and to monitor the evolution of liver damage. They also argue for a potential pathophysiological role for IL-10 in the persistence and progression of hepatitis.

Cytogenetic methods for detection of oxidative stress and evaluation of antioxidant therapy in hepatitis C infection

The plasma of patients with hepatitis C contains chromosome-damaging substances, the so-called "clastogenic factors" (CFs), as this is the case for other chronic inflammatory diseases and after radiation exposure. These endogenous clastogens, formed as a consequence of increased superoxide production by inflammatory cells, can be detected with cytogenetic methods, as they are used for exogenous clastogens. The long-lived, autosustained DNA-damaging effects of CFs are risk factors for the development of cancer and leukemia. In hepatitis C, the highest clastogenic scores has been observed in patients with hepatocellular carcinoma. In agreement with the link to inflammation, clastogenic score are correlated with necro-inflammatory scores in liver biopsies. Antioxidant therapy with a powerful superoxide scavenger resulted in normalization of clastogenic scores and significant decreases in aminotransferase levels, but did not influence the virus load. Preliminary results of our study on a limited number of patients suggest that pre-treatment with antioxidants may improve the outcome of interferon/ribavirin treatment. A comparison of a three-month treatment with either interferon alone or the antioxidant alone, yielded similar results for reduction of ALT levels, but only complete normalization of clastogenic scores for the antioxidant. Further studies have to be conducted to see whether a combination of an antiviral agent with an appropriate antioxidant would allow to reduce interferon and its side effects.Combination of antioxidants with IFN/RIBA was also reported by other authors with discordant results. The CF-test can be useful in clinical trials for the choice of the appropriate antioxidant.

Cyclosporin A associated helicase-like protein facilitates the association of hepatitis C virus RNA polymerase with its cellular cyclophilin B

Background

Cyclosporin A (CsA) is well known as an immunosuppressive drug useful for allogeneic transplantation. It has been reported that CsA inhibits hepatitis C virus (HCV) genome replication, which indicates that cellular targets of CsA regulate the viral replication. However, the regulation mechanisms of HCV replication governed by CsA target proteins have not been fully understood.

Principal Findings

Here we show a chemical biology approach that elucidates a novel mechanism of HCV replication. We developed a phage display screening to investigate compound-peptide interaction and identified a novel cellular target molecule of CsA. This protein, named CsA associated helicase-like protein (CAHL), possessed RNA-dependent ATPase activity that was negated by treatment with CsA. The downregulation of CAHL in the cells resulted in a decrease of HCV genome replication. CAHL formed a complex with HCV-derived RNA polymerase NS5B and host-derived cyclophilin B (CyPB), known as a cellular cofactor for HCV replication, to regulate NS5B-CyPB interaction.

Conclusions

We found a cellular factor, CAHL, as CsA associated helicase-like protein, which would form trimer complex with CyPB and NS5B of HCV. The strategy using a chemical compound and identifying its target molecule by our phage display analysis is useful to reveal a novel mechanism underlying cellular and viral physiology.

HCV synergizes with body weight in the promotion of insulin resistance

Hepatitis C virus (HCV) infection appears to contribute to the development of insulin resistance (IR). Among the multiple determinants of IR, body mass index (BMI) is the most important. We investigated the contribution of HCV to BMI-associated IR using a transgenic mouse model expressing HCV core protein. Eight transgenic and five nontransgenic littermate controls were evaluated. Glucose and insulin tolerance tests (ITT) were performed on two separate occasions. Multivariate linear mixed modelling was used to evaluate and compare the effect of weight on IR between HCV core transgenic and nontransgenic controls. There were no statistically significant differences in glucose or ITT (P = 0.58 and P = 0.59, respectively) between the two groups, and no difference in median weights between transgenic and control mice (P = 0.11). However, there was greater variance in the distributions of Tg when compared to nontransgenic mice for both glucose and insulin tolerance. When evaluating this closely, a differential contribution of weight to IR curves between these groups was noted (P = 0.05). Among nontransgenic mice, IR curves for mice of different weights were comparable, however, for transgenic mice, higher weights resulted in larger levels of IR curves with slower decay. In all animals, steatosis was absent or minimal. We conclude that weight has a greater effect on IR in HCV core expressing transgenic mice than littermate controls. HCV therefore synergizes with weight in the promotion of IR. Steatosis was not a prerequisite for the development of IR, implying that HCV's effects on IR may be independent of steatosis.

Effects of multiple-dose pegylated interferon alfa-2b on the activity of drug-metabolizing enzymes in persons with chronic hepatitis C

PURPOSE

To examine the effect of pegylated interferon (PEG-IFN) alfa-2b on the activity of major drug-metabolizing enzymes.

METHODS

This nonrandomized, open-label, multiple-dose study examined the effects of PEG-IFN alfa-2b on the activity of CYP450 1A2, 2 C8/9, 2D6, and 3A4 enzymes and N-acetyltransferase in subjects with chronic hepatitis C. Eligible subjects received PEG-IFN alfa-2b 1.5 μg/kg subcutaneously once weekly for 4 weeks (days 3, 10, 17, and 24). Oral probe substrates (dextromethorphan hydrobromide 45 mg, caffeine 200 mg, tolbutamide 500 mg, and dapsone 100 mg) were administered after a 10-h fast on days 1 and 25. Midazolam 4 mg was administered orally on days 2 and 26. Enzyme activity for each CYP450 isozyme and for N-acetyltransferase was estimated based on the ratios of the observed concentrations of the substrates and metabolites in plasma or urine samples.

RESULTS

Twenty-six subjects enrolled in the study. Mean age was 44.3 years, mean weight was 78.9 kg, and mean body mass index was 26.3 kg/m(2). Multiple doses of PEG-IFN alfa-2b inhibited CYP1A2 activity to a limited extent (point estimate = 84.2%, 90% confidence interval [CI] 79-90), increased CYP2C8/9 activity to a limited extent (point estimate = 127.6%, 90% CI 115-142), increased CYP2D6 activity (point estimate = 167%, 90% CI 125-223), and had no effect on the activity of CYP3A4 or N-acetyltransferase.

CONCLUSION

Weekly administration of PEG-IFN alfa-2b to subjects with chronic hepatitis C increased CYP2C8/9 and CYP2D6 activity in some individuals.

Pharmacokinetics and response of obese patients with chronic hepatitis C treated with different doses of PEG-IFN alpha-2a (40KD) (PEGASYS)

AIMS

To evaluate whether higher doses of peginterferon alpha-2a (40KD) [PEG-IFN alpha-2a (40KD)] can compensate for lower exposure observed among obese patients with chronic hepatitis C (CHC) treated with the standard dose of PEG-IFN alpha-2a (40KD).

METHODS

Noncirrhotic, obese (body mass index > or =30 kg m(-2)) patients with CHC participated in a single-centre, open-label study. Patients were randomized to 180 or 270 microg week(-1) PEG-IFN alpha-2a (40KD) + ribavirin (1000/1200 mg day(-1)) for 48 weeks. Blood samples were collected predose and up to 168 h after the first dose and at week 12 for pharmacokinetic analysis. Trough serum concentrations (C(trough)) were determined up to week 24.

RESULTS

In the 180 microg week(-1) group mean +/- SD steady-state (week 12) estimates of AUC(0-168) (ng h(-1) ml(-1)), C(max) (ng ml(-1)) and CL/F (l h(-1)) were 2154 +/- 919, 13.8 +/- 6.7 and 0.102 +/- 0.051, respectively. In the 270 microg week(-1) group, estimates were 3374 +/- 1844, 23.4 +/- 10.7 and 0.090 +/- 0.042, respectively. The mean (range) C(trough) (ng ml(-1)) was 11.2 (4.4-18.5) in the 180 microg week(-1) group and 16.1 (0.4-44.2) in the 270 microg week(-1) group. Overall, 14 of 20 (70%) and 16 of 20 (80%) patients in the 180 microg week(-1) and 270 microg week(-1) groups were infected with hepatitis C virus genotype 1 or 4. In the 180 microg week(-1) and 270 microg week(-1) groups 14 of 20 (70%) and 15 of 19 (79%) patients, respectively, achieved a sustained viral response. Safety was similar between groups.

CONCLUSIONS

Mean PEG-IFN alpha-2a (40KD) exposure was dose proportional from 180 to 270 microg week(-1). Increasing PEG-IFN alpha-2a (40KD) from 180 to 270 microg week(-1) achieves higher serum drug exposure in obese patients.

Predicting the probable outcome of treatment in HCV patients

Hepatitis C virus (HCV) is a major cause of chronic liver disease infecting more than 170 million people worldwide. HCV produces a wide gamut of manifestations varying from mild self-limiting disease to cirrhosis and hepatocellular carcinoma. A variety of viral, environmental and host genetic factors contribute to the clinical spectrum of patients infected with HCV and influence response to interferon (IFN) therapy. Predicting the probable outcome of treatment in patients with HCV infection has always been a challenging task. Treatment of HCV by pegylated interferon (peg-IFN) plus ribavirin eradicates the virus in approximately 60% of patients - HCV genotype 1 (42-51% response rates) and genotypes 2 and 3 (76-84% response rates); however, a significant number of patients do not respond to therapy or relapse following discontinuation of treatment or have significant side effects that preclude further treatment. Accurately predicting the patients who will respond to therapy is becoming increasingly important, both from the point of patient care and also with respect to the healthcare cost as clinicians need to continue treatment in patients who will respond and stop treatment in patients who are unlikely to respond. Viral RNA measurements and genotyping are used to optimize treatment as a low viral load and nongenotype 1 is more likely to be associated with sustained virological response (SVR). Rapid virological response (RVR) defined by undetectable HCV RNA at 4 weeks of treatment is increasingly being recognized as a powerful tool for predicting treatment response. A variety of host factors including single nuclear polymorphisms (SNPs) of IFN response genes, insulin resistance, obesity, ethnicity, human leukocyte antigens and difference in T-cell immune response has been found to modulate the response to antiviral treatment. The presence of severe fibrosis/cirrhosis on pretreatment liver biopsy predicts a poor response to treatment. Recent studies on gene expression profiling and characterization of the liver and serum proteome provide options to accurately predict the outcome of patients infected with HCV in the future. Future studies on the factors that predict treatment response and tailoring treatment based on this is required if we are to conquer this disease.

Inhibition of intrahepatic gamma interferon production by hepatitis C virus nonstructural protein 5A in transgenic mice

Hepatitis C virus (HCV) utilizes strategies to suppress or evade the host immune response for establishment of persistent infection. We have shown previously that HCV nonstructural protein 5A (NS5A) impairs tumor necrosis factor alpha (TNF-alpha)-mediated apoptosis. In this study, we have examined the immunomodulatory role of HCV NS5A protein in transgenic mouse (NS5A-Tg) liver when mice were challenged with an unrelated hepatotropic adenovirus as a nonspecific stimulus. Hepatotropic adenovirus was introduced intravenously into NS5A-Tg mice and control mice, and virus clearance from liver was compared over a time course of 3 weeks. The differential mRNA expression levels of 84 cytokine-related genes, signal pathway molecules, transcription factors, and cell surface molecules were determined using real-time reverse transcription-PCR array. NS5A-Tg mice failed to clear adenovirus from liver up to 3 weeks postinfection while control mice cleared virus within 1 to 2 weeks. Subsequent study revealed that gamma interferon (IFN-gamma) expression is inhibited at both the mRNA and protein levels in NS5A-Tg mice, and an inverse expression of transcription factors Gata-3 and Tbx21 is observed. However, TNF-alpha mRNA and protein expression were elevated in both NS5A-Tg and control mice. Together, our results suggested that HCV NS5A acts as an immunomodulator by inhibiting IFN-gamma production and may play an important role toward establishment of chronic HCV infection.

Liver diseases and metabolic syndrome

Emerging attention has been paid to metabolic syndrome, which comprises several metabolic disorders including visceral obesity, diabetes mellitus, dyslipidemia, and hypertension. Whether the severity of each disease is mild to moderate, the comorbidity of these metabolic disorders has a serious impact on the development of atherosclerosis. Nonalcoholic fatty liver disease (NAFLD) is the major hepatic disorder in patients with metabolic syndrome, and indeed it is the most common cause of abnormal liver function tests in the working population in industrialized countries. In recent years, it has become recognized that NAFLD is no longer just a trivial disease, and a rather considerable proportion of the patients develop liver cirrhosis. Furthermore, chronic infection of hepatitis C virus also develops a pathological feature of steatohepatitis, and extended hepatic steatosis has a serious impact not only on the progression of hepatic fibrosis but also on the antiviral efficacy of interferon therapy. Emerging lines of studies indicated that insulin resistance, abnormal lipid metabolism, and dysregulation of cytokines/adipokines (e.g., tumor necrosis factor-alpha, adiponectin, and leptin) are profoundly involved in the pathogenesis of NAFLD. This review aims to integrate the reported evidence and to provide the current point of view for comprehensive understanding of the pathophysiology of steatohepatitis.

Cytokine levels of TGF-beta, IL-10, and sTNFalphaRII in type C chronic liver disease

Cytokines play a key role in regulation of immunity and inflammation. The aim of the study was to detect serum levels of TGF-beta, IL-10, and sTNFalphaRII in patients with type C chronic liver disease (CLD) and to correlate these with biochemical and histopathological parameters used to assess the severity of the disease. Blood samples were aseptically collected from 90 CLD patients. Cytokine levels were also followed up in 39 chronic hepatitis cases. Levels of the cytokines in 90 CLD patients were significantly higher than in controls. In the follow up patients, 12 were non-responders and the serum levels of cytokines were still elevated after therapy whereas in 27 responders cytokine levels were significantly reduced after therapy and correlated well with biochemical and histopathological parameters. It is inferred that cytokine levels reflect the level of inflammation in chronic hepatitis C virus (HCV) infection and can be used as indirect markers to assess the severity of liver disease.

Clastogenic factors as potential biomarkers of increased superoxide production

The formation of clastogenic factors (CF) and their damaging effects are mediated by superoxide, since superoxide dismutase is regularly protective. CF are produced via superoxide and stimulate the production of superoxide by monocytes and neutrophils. This results in a selfsustaining and longlasting process of clastogenesis, which may exceed the DNA repair system and ultimately lead to cancer (Emerit, 1994). An increased cancer risk is indeed observed in conditions accompanied by CF formation. These include irradiated persons, patients with chronic inflammatory diseases, HIV-infected persons and the chromosomal breakage syndromes ataxia telangiectasia, Bloom's syndrome and Fanconi's anemia. Biochemical analysis has identified lipid peroxidation products, arachidonic acid metabolites, nucleotides of inosine and cytokines, in particular tumor necrosis factor alpha, as the clastogenic and also superoxide stimulating components of CF. Due to their chromosome damaging effects, these oxidants can be detected with classical cytogenetic techniques. Their synergistic action renders the CF-test particularly sensitive for the detection of a pro-oxidant state. Correlations were observed between CF and other biomarkers of oxidative stress such as decreases in total plasma thiols or increases in TBARS or chemiluminescence. Correlations between CF and disease activity, between CF and radiation exposure, suggest the study of CF for monitoring these conditions. CF may also be useful as biochemical markers and intermediate endpoints for the evaluation of promising antioxidant drugs.CF formation represents a link between chronic inflammation and carcinogenesis. Prophylactic use of superoxide scavengers as anticarcinogens is therefore suggested.

Mechanisms and significance of liver steatosis in hepatitis C virus infection

The pathogenesis of liver damage associated with chronic hepatitis C virus (HCV) infection is thought to be largely immunomediated. However, some frequent histopathological features, such as steatosis, suggest a direct cytopathic effect of HCV. The direct responsibility of HCV in the pathogenesis of steatosis is shown by: (1) the association with HCV genotype 3 infection, suggesting that some viral sequences are involved in the intracellular accumulation of lipids; (2) the correlation between severity of steatosis and HCV replication levels; (3) association between response to treatment and disappearance of steatosis. Experimental studies have shown that the nucleocapsid protein of HCV (core protein) is capable and sufficient to induce lipid accumulation in hepatocytes. Moreover, the observation that chronic hepatitis C patients have reduced serum levels of ApoB suggests an interference with the very-low density lipoprotein (VLDL) assembly, although other mechanisms are possible. In patients with sustained virological response induced by antiviral therapy, such levels are normalized. Other observations suggest that the pathogenesis of steatosis in chronic hepatitis C is not solely due to HCV. The origin of the mild steatosis observed in most patients may be metabolic, since its severity correlates with body mass index and insulin resistance. Most studies have shown a correlation between presence and/or severity of steatosis and fibrosis stage, but it is unclear whether this effect is direct or mediated by the associated insulin resistance, increased susceptibility to apoptosis, or by inflammatory cytokines. Finally, steatosis negatively influences the rate of response to antiviral treatment, as confirmed by large clinical trials. Management of steatosis in chronic hepatitis C requires knowledge of its pathogenesis and may involve both life-style changes and pharmacological interventions, although the latter remain largely experimental.

Non-response to antiviral therapy is associated with obesity and increased hepatic expression of suppressor of cytokine signalling 3 (SOCS-3) in patients with chronic hepatitis C, viral genotype 1

BACKGROUND

Interferon alpha (IFN-alpha) activated cellular signalling is negatively regulated by inhibitory factors, including the suppressor of cytokine signalling (SOCS) family. The effects of host factors such as obesity on hepatic expression of these inhibitory factors in subjects with chronic hepatitis C virus (HCV) are unknown.

OBJECTIVES

To assess the independent effects of obesity, insulin resistance, and steatosis on response to IFN-alpha therapy and to determine hepatic expression of factors inhibiting IFN-alpha signalling in obese and non-obese subjects with chronic HCV.

METHODS

A total of 145 subjects were analysed to determine host factors associated with non-response to antiviral therapy. Treatment comprised IFN-alpha or peginterferon alpha, either alone or in combination with ribavirin. In a separate cohort of 73 patients, real time-polymerase chain reaction was performed to analyse hepatic mRNA expression. Immunohistochemistry for SOCS-3 was performed on liver biopsy samples from 38 patients with viral genotype 1 who had received antiviral treatment.

RESULTS

Non-response (NR) to treatment occurred in 55% of patients with HCV genotypes 1 or 4 and 22% with genotypes 2 or 3. Factors independently associated with NR were viral genotype 1/4 (p < 0.001), cirrhosis on pretreatment biopsy (p = 0.025), and body mass index > or = 30 kg/m2 (p = 0.010). Obese subjects with viral genotype 1 had increased hepatic mRNA expression of phosphoenolpyruvate carboxy kinase (p = 0.01) and SOCS-3 (p = 0.047), in comparison with lean subjects. Following multivariate analysis, SOCS-3 mRNA expression remained independently associated with obesity (p = 0.023). SOCS-3 immunoreactivity was significantly increased in obesity (p = 0.013) and in non-responders compared with responders (p = 0.014).

CONCLUSIONS

In patients with chronic HCV viral genotype 1, increased expression of factors that inhibit interferon signalling may be one mechanism by which obesity reduces the biological response to IFN-alpha.

Association of pretreatment serum interferon gamma inducible protein 10 levels with sustained virological response to peginterferon plus ribavirin therapy in genotype 1 infected patients with chronic hepatitis C

BACKGROUND

Increased serum and intrahepatic interferon gamma inducible protein 10 (IP-10) levels in patients with chronic hepatitis C (CHC) have been described.

AIM

To analyse the possible association of serum IP-10 levels with different outcomes to antiviral therapy.

PATIENTS

A total of 137 CHC patients treated with peginterferon plus ribavirin.

METHODS

Serum IP-10 levels were determined by enzyme linked immunosorbent assay before therapy, after 12 weeks of treatment, and 24 weeks after cessation of therapy. Variables significantly associated with a sustained virological response (SVR) on univariate analysis were included in a multivariate logistic regression model.

RESULTS

Pretreatment serum IP-10 levels in patients with SVR were significantly lower than in non-responders (NR) (332.4 (222.1) v 476.8 (305.3) pg/ml, respectively; p=0.004). Serum IP-10 concentrations significantly decreased in patients with SVR (pretreatment: 332.4 (222.1) pg/ml; post-treatment: 170.2 (140.1) pg/ml; p<0.001) but not in NR (pretreatment: 476.8 (305.3) pg/ml; post treatment: 387.3 (268.1) pg/ml; p=0.06). By multivariate analysis, non-1 genotype (odds ratio (OR) 3.5 (95% confidence interval (CI) 1.1-10.4); p=0.003) and low viral load at baseline (OR 0.34 (95% CI 0.14-0.79); p=0.01) were independent predictors of SVR in all patients. When multivariate analysis was restricted to patients with genotype 1, only baseline viral load (OR 0.38 (95% CI 0.155-0.96); p=0.04) and pretreatment serum IP-10 levels (OR 0.99 (95% CI 0.996-0.999); p=0.03) were identified as predictive factors of SVR.

CONCLUSION

Pretreatment serum IP-10 behaves as a predictive factor of SVR to peginterferon plus ribavirin therapy in genotype 1 infected patients.

Safety of antitumour necrosis factor (anti-TNF) therapy in patients with chronic viral infections: hepatitis C, hepatitis B, and HIV infection

Tumour necrosis factor alpha (TNFalpha) is a pivotal cytokine in host defences with broad ranging effects on the innate and adaptive immune systems. Clinically, TNFalpha inhibitors have demonstrated remarkable efficacy in a wide range of autoimmune and inflammatory disorders but clearly at the cost of heightened susceptibility to a variety of infections in those treated with these agents. Most reports to date have described increased susceptibility to intracellular pathogens in patients with underlying chronic viral infections, but little in the way of adverse event reporting in these patients has occurred. While the reported experience to date is rather limited, TNFalpha inhibitors have displayed a reasonable safety profile in the setting of some chronic viral infections and in certain circumstances have demonstrated adjunctive activity in the treatment of these infections. Given the high prevalence of chronic viral infections in patients who are candidates for anti-TNF therapy and the potential for these agents in the treatment of chronic viral illness, additional studies are urgently needed to assess the risks and benefits of such therapy in these populations.

In vitro activation of cord blood mononuclear cells and cytokine production in a remote coastal population exposed to organochlorines and methyl mercury

Remote coastal populations that rely on seafood for subsistence often receive unusually high doses of organochlorines and methyl mercury. Immunosuppression resulting from prenatal exposure to organochlorines has been reported in wildlife species and humans. In this study, we assessed lymphocyte activation and associated cytokine secretion in 47 newborns from a remote maritime population living on the Mid and Lower North Shore regions of the St. Lawrence River (Québec, Canada; subsistence fishing group) and 65 newborns from nearby urban settings (reference group). Cord blood samples were collected for organochlorine and mercury analyses and also to isolate cord blood mononuclear cells (CBMCs) for the in vitro assessment of cytokine production and expression of surface markers after mitogenic stimulation (CD4(+)CD45RO(+), CD8(+)CD45RO(+), CD3(+)CD25(+), and CD8(+)HLA-DR(+)). Blood mercury and plasma concentrations of polychlorinated biphenyls (PCBs), 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (p,p'-DDE), and hexachlorobenzene (HCB) were significantly higher in the subsistence fishing group than in the reference group (p < 0.001). No difference was observed between the two groups regarding subsets of lymphocytes showing markers of activation. In vitro secretion of cytokines by CBMCs after mitogenic stimulation was lower in the subsistence fishing group than in the reference group (p < 0.05). Moreover, we found an inverse correlation between tumor necrosis factor-alpha (TNF-alpha) secretion and plasma PCB, p,p'-DDE, and HCB concentrations (p < 0.05). Our data support a negative association between TNF-alpha secretion by CBMCs and prenatal organochlorine exposure. If the relationship between organochlorine and TNF-alpha secretion is causal, it would suggest a role for this important proinflammatory cytokine in mediating organochlorine-induced immunotoxicity in infants developmentally exposed to these compounds.

Interferon-alpha induces interleukin-18 binding protein in chronic hepatitis C patients

Interleukin-18 (IL-18), derived from macrophages and Kupffer cells, is the central pro-inflammatory cytokine leading to experimental liver failure. IL-18 binding protein (IL-18BP) is a circulating protein that binds IL-18 and neutralizes its activity. Since IL-18 production is increased in chronic HCV infection, we asked whether IFN-alpha might act on the IL-18/IL-18BP system in HCV patients. IL-18BP, total and free IL-18 plasma levels were determined in 13 HCV patients receiving 1 x 107 IU IFN-alpha subcutaneously daily for 28 days. The in vitro effects of IFN-alpha on macrophage IL-18BP and IL-18 were studied by enzyme-linked immunosorbent assays and Northern analysis. IFN-alpha administration increased IL-18BP plasma levels 3.24 fold 24 h after institution of therapy, resulting in a 67.4% reduction of free IL-18. Total IL-18 levels decreased from day +24 on. In vitro, IFN-alpha diminished IL-18 release from macrophages of healthy volunteers and chronic HCV patients. On top of its inhibitory effects on IL-1 and TNF-alpha release, IFN-alpha also exerts its anti-inflammatory action in vivo by induction of IL-18BP. These anti-inflammatory properties might account - together with its antiviral action - for its clinical efficacy in chronic hepatitis C.

Protection against Fas-mediated and tumor necrosis factor receptor 1-mediated liver injury by blockade of FADD without loss of nuclear factor-kappaB activation

OBJECTIVE

To investigate the role of FADD (Fas-associated protein with death domain) in Fas and tumor necrosis factor receptor 1 (TNFR1)-mediated hepatic injury and inflammatory response in vivo.

SUMMARY BACKGROUND DATA

Fas and TNFR1 are cell surface molecules that trigger apoptosis or inflammation on engagement by a specific ligand or antibody. FADD is recruited to the cytoplasmic domain of these receptors on their activation and works as a common mediator to induce apoptosis. It is known that a blockade of FADD can inhibit apoptosis mediated by Fas or TNFR1 in vitro. However, it is not known whether the blockade can prevent organ injury and whether the inflammatory cascade is affected in vivo.

METHODS

A FADD deletion mutant lacking the death effector domain was introduced into mice by transduction with an adenovirus vector, and the effect of this FADD dominant negative mutant was examined in several liver injury models.

RESULTS

Hepatic injury induced by anti-Fas monoclonal antibody or tumor necrosis factor (TNF)-alpha plus D-galactosamine was markedly ameliorated by the FADD dominant negative transduction, which abrogated the death rate. Further, the FADD dominant negative transduction efficiently blocked T cell- mediated concanavalin A-induced hepatitis while not affecting TNF-alpha production or TNF-alpha-induced nuclear factor-kappaB activation in the liver.

CONCLUSIONS

These results provide the basis for a novel therapeutic modality in which an unfavorable apoptotic process can be inhibited without affecting a favorable response for liver regeneration; this would be relevant to the clinical treatment of acute and chronic liver diseases as well as to some inflammatory disorders with hypercytokinemia, such as sepsis.

Kinetics of serum soluble tumour necrosis factor receptor (TNF-R) type-I and type-II after a single interferon-alpha (IFN-alpha) injection in chronic hepatitis C

Circulating soluble TNF receptors, which act as TNF inhibitors, increase following the administration of IFN-alpha. Whether this is due to a direct IFN action or to indirect mechanisms involving the release of other cytokines is unclear. The kinetics of serum IFN, TNF, IL-6, IL-10, soluble TNF receptor type-I (sTNF-RI) and sTNF-RII were evaluated by enzyme immunoassays in 11 patients with chronic hepatitis C, following the first dose of recombinant human IFN-alpha2b (3 MU given subcutaneously). sTNF-RI concentrations paralleled IFN concentrations, rising from a mean +/- s.e.m. value of 3.5 +/- 0.3 ng/ml at baseline to a peak value of 5.5 +/- 0.5 ng/ml after 9 h, followed by a return to 4.1 +/- 0.4 ng/ml after 24 h (P = 0.0001). sTNF-RII concentrations, which were 7.6 +/- 0.5 ng/ml at baseline, fell initially to 6.9 +/- 0.5 ng/ml, to reach a peak at 24 h of 9.0 +/- 0.7 ng/ml (P < 0.0001). In contrast, the concentrations of TNF, IL-6 and IL-10 fluctuated with no significant changes at any time point. The area under the curve (AUC) of incremental IFN values had a strong positive correlation with the AUC of incremental sTNF-RI values (r = 0.75, P < 0.01). In patients with hepatitis C, IFN concentrations reached after a single dose of IFN were paralleled by correlationally increased concentrations of sTNF-RI, which are a much better marker of administered IFN than sTNF-RII, IL-6 or IL-10.

Hepatitis C virus recurrence after liver transplantation

Cirrhosis due to hepatitis C virus (HCV) is now the most common indication of liver transplantation in Western Europe and the United States. In the absence of effective prophylaxis, recurrent HCV infection is almost inevitable. Though the natural history and intermediate term outcome of recurrent HCV are now better documented, those factors which may influence the recurrence of hepatitis and consequent progression of graft disease remain unclear. Interferon (IFN) as a sole agent for the treatment of recurrent infection has proved unsatisfactory. Early intervention with a combination of IFN and ribavirin seems promising, and this approach may prevent or delay progression of HCV related graft disease after liver transplantation.

Mesalamine blocks tumor necrosis factor growth inhibition and nuclear factor kappaB activation in mouse colonocytes

BACKGROUND & AIMS

Derivatives of 5-aminosalicylic acid (mesalamine) represent a mainstay in inflammatory bowel disease therapy, yet the precise mechanism of their therapeutic action is unknown. Because tumor necrosis factor (TNF)-alpha is important in the pathogenesis of inflammatory bowel disease, we investigated the effect of mesalamine on TNF-alpha-regulated signal transduction and proliferation in intestinal epithelial cells.

METHODS

Young adult mouse colon cells were studied with TNF-alpha, epidermal growth factor, or ceramide in the presence or absence of mesalamine. Proliferation was studied by hemocytometry. Mitogen-activated protein (MAP) kinase activation and IkappaBalpha expression were determined by Western blot analysis. Nuclear transcription factor kappaB (NF-kappaB) nuclear translocation was determined by confocal laser immunofluorescent microscopy.

RESULTS

The antiproliferative effects of TNF-alpha were blocked by mesalamine. TNF-alpha and ceramide activation of MAP kinase were inhibited by mesalamine, whereas epidermal growth factor activation of MAP kinase was unaffected. TNF-alpha-stimulated NF-kappaB activation and nuclear translocation and the degradation of Ikappa-Balpha were blocked by mesalamine.

CONCLUSIONS

Mesalamine inhibits TNF-alpha-mediated effects on intestinal epithelial cell proliferation and activation of MAP kinase and NF-kappaB. Therefore, it may function as a therapeutic agent based on its ability to disrupt critical signal transduction events in the intestinal cell necessary for perpetuation of the chronic inflammatory state.

Expression and regulation of cell adhesion molecules by hepatic stellate cells (HSC) of rat liver: involvement of HSC in recruitment of inflammatory cells during hepatic tissue repair

Hepatic stellate cells (HSC), a pericyte-like nonparenchymal liver cell population, are regarded as the principal matrix-synthesizing cells of fibrotic liver. They might also play a role during liver inflammation. The present study analyzed (i) expression of cell adhesion molecules (CAMs) mediating cell infiltration, like intercellular adhesion molecule-1 (I-CAM-1) and vascular cell adhesion molecule-1 (V-CAM-1), by HSC, (ii) CAM regulation in HSC by growth factors and inflammatory cytokines, and (iii) CAM expression in situ during liver inflammation, using immunochemistry and Northern blot analysis. I-CAM-1 and V-CAM-1 expression was present in HSC in vitro and in cells located in the sinusoidal/perisinusoidal area of normal liver. Growth factors, eg, transforming growth factor-beta1, down-regulated I-CAM-1- and V-CAM-1-coding mRNAs and stimulated N-CAM expression of HSC. In contrast, inflammatory cytokines like tumor necrosis factor-alpha reduced N-CAM-coding mRNAs, whereas induction of I-CAM-1- and V-CAM-1-specific transcripts increased several fold. In situ, messengers specific for I-CAM-1 and V-CAM-1 were induced 3 hours after CCl4 treatment (thereby preceding mononuclear cell infiltration starting at 12 hours), were expressed at maximal levels 9-12 hours after CCl4 application, and decreased afterwards. I-CAM-1 and V-CAM-1 immunoreactivity increased in a linear fashion starting 3 hours after CCl4-induced liver injury, was detected in highest amounts at 24-48 hours characterized by maximal cell infiltration, and returned to baseline values at 96 hours. Interestingly, the induction/repression of CAM-specific messengers paralleled the time kinetics of tumor necrosis factor-alpha transforming growth factor-beta1 expression in injured liver. HSC might be important during the onset of hepatic tissue injury as proinflammatory elements and might interact with I-CAM-1 and V-CAM-1 ligand-bearing cells, namely lymphocyte function-associated antigen-1- or Mac-1/very late activation antigen-4-positive inflammatory cells, thereby modulating the recruitment and migration of mononuclear cells within the perisinusoidal space of diseased livers.

Hepatitis C virus core protein binds to the cytoplasmic domain of tumor necrosis factor (TNF) receptor 1 and enhances TNF-induced apoptosis

The hepatitis C virus (HCV) core protein is known to be a multifunctional protein, besides being a component of viral nucleocapsids. Previously, we have shown that the core protein binds to the cytoplasmic domain of lymphotoxin beta receptor, which is a member of tumor necrosis factor receptor (TNFR) family. In this study, we demonstrated that the core protein also binds to the cytoplasmic domain of TNFR 1. The interaction was demonstrated both by glutathione S-transferase fusion protein pull-down assay in vitro and membrane flotation method in vivo. Both the in vivo and in vitro binding required amino acid residues 345 to 407 of TNFR 1, which corresponds to the "death domain" of this receptor. We have further shown that stable expression of the core protein in a mouse cell line (BC10ME) or human cell lines (HepG2 and HeLa cells) sensitized them to TNF-induced apoptosis, as determined by the TNF cytotoxicity or annexin V apoptosis assay. The presence of the core protein did not alter the level of TNFR 1 mRNA in the cells or expression of TNFR 1 on the cell surface, suggesting that the sensitization of cells to TNF by the viral core protein was not due to up-regulation of TNFR 1. Furthermore, we observed that the core protein blocked the TNF-induced activation of RelA/NF-kappaB in murine BC10ME cells, thus at least partially accounting for the increased sensitivity of BC10ME cells to TNF. However, NF-kappaB activation was not blocked in core protein-expressing HeLa or HepG2 cells, implying another mechanism of TNF sensitization by core protein. These results together suggest that the core protein can promote cell death during HCV infection via TNF signaling pathways possibly as a result of its interaction with the cytoplasmic tail of TNFR 1. Therefore, TNF may play a role in HCV pathogenesis.

Activation of tumor necrosis factor-alpha system in chronic hepatitis C virus infection

Tumor necrosis factor-alpha (TNF-alpha) plays a central role in the host's immunomodulatory response to infective agents. To evaluate the TNF-alpha system in patients with chronic hepatitis C virus (HCV) infection, plasma, serum, and peripheral blood mononuclear cells (PBMC) were prospectively collected from 53 patients and 33 healthy control subjects. Circulating TNF-alpha and TNF receptors were assayed by their respective enzyme immunoassays. In addition, TNF-alpha mRNA was quantitated in PBMC using a branched DNA assay, and production of TNF-alpha by PBMC with and without lipopolysaccharide was also assessed. Patients with chronic HCV infection had a higher level of circulating TNF-alpha compared to healthy control subjects (9.62 +/- 6.01 vs 3.66 +/- 1.23 pg/ml, P < 0.001). They also had higher circulating levels of TNF receptors compared to control (CD120a: 3323 +/- 1267, pg/ml, N = 49 vs 1855 +/- 422 pg/ml, N = 33, P < 0.001; CD120b: 1290 +/- 650 pg/ml, N = 51, vs 863 +/- 207 pg/ml, N = 33, P < 0.001). Plasma TNF-alpha level correlated with circulating CD120a (r = 0.52, N = 49, P < 0.001) and weakly with CD120b (r = 0.32, N = 51, P = 0.02). Plasma TNF-alpha also correlated with markers of hepatocellular injury, including ALT (r = 0.34, N = 53, P = 0.01) and alpha-GST (r = 0.31, N = 43, P = 0.042), but not with serum HCV RNA levels. There was no difference in the TNF-alpha mRNA levels in PBMC between patients with chronic HCV infection (1.4 +/- 1.9 units/10[6] cells, N = 8) and healthy control subjects (2.1 +/- 1.4 units/10[6] cells, N = 8, P = NS). There was also no difference in the spontaneous production of TNF-alpha by PBMC (1 x 10[6] cells/ml) between patients with chronic HCV infection (14.2 +/- 36.5 pg/ml, N = 11) and healthy subjects (11.9 +/- 14.0 pg/ml, N = 14, P = NS). However, patients with chronic HCV infection produced more TNF-alpha upon stimulation with lipopolysaccharide compared to healthy control subjects (1278 +/- 693 pg/ml, N = 11, vs 629 +/- 689 pg/ml, N = 14, P < 0.05). These data indicate that the TNF-alpha system is activated in patients with chronic HCV infection.

Induction of tumour necrosis factor (TNF) receptor type p55 and p75 in patients with chronic hepatitis C virus (HCV) infection

There is evidence that TNF-alpha contributes to the pathogenesis of chronic viral hepatitis. The cellular effects of this cytokine are regulated by two specific receptors, and membranous shedding of these receptors reflects activation of the TNF system. We performed a study of TNF-alpha and functionally active soluble TNF-receptors (TNFR-p55 and -p75) in 105 patients with chronic HCV infection. In HCV RNA-positive patients a significant enhancement of TNF-alpha and both receptor types was observed compared with controls (TNF-alpha 83.8+/-91.7 pg/ml versus 18.8+/-8.4 pg/ml, P<0.001; TNFR-p55 1.4+/-0.4 ng/ml versus 0.9+/-0.2 ng/ml, P<0.0001; TNFR-p75 6.4+/-2.4 ng/ml versus 2.9+/-0.6 ng/ml, P<0.0001, respectively). The enhanced serum levels of TNF-alpha and TNFRs were reflected by a significant expression of TNFR-specific mRNA in peripheral mononuclear cells of HCV-infected patients (P<0.001). Serum aminotransferases correlated with soluble TNFR-p75 (P<0.001) but not with TNFR-p55 and TNF-alpha. We demonstrated an association of the degree of histological inflammation with both TNFRs (P<0.01). Furthermore, enhanced hepatocellular expression of TNF-alpha and TNFRs could be demonstrated by immunohistochemical staining in HCV-infected patients. Sixty-eight out of 105 patients were treated with interferon-alpha (IFN-alpha) (3x10(6)U x 3/week). Pretreatment levels of TNF-alpha and TNFRs did not differ between responders and non-responders. Our results demonstrate that TNF-alpha and TNFRs are enhanced in chronic HCV infection and reflect histological activity of the disease. This up-regulation of TNFRs might modify host response and potentially contribute to liver damage in chronic HCV infection.