Effect of interferon alpha and ribavirin treatment on serum levels of transforming growth factor-β1, vascular endothelial growth factor, and basic fibroblast growth factor in patients with chronic hepatitis C

Strategies Targeting the Innate Immune Response for the Treatment of Hepatitis C Virus-Associated Liver Fibrosis

Direct-acting antivirals eliminate hepatitis C virus (HCV) in more than 95% of treated individuals and may abolish liver injury, arrest fibrogenesis, and reverse fibrosis and cirrhosis. However, liver regeneration is usually a slow process that is less effective in the late stages of fibrosis. What is more, fibrogenesis may prevail in patients with advanced cirrhosis, where it can progress to liver failure and hepatocellular carcinoma. Therefore, the development of antifibrotic drugs that halt and reverse fibrosis progression is urgently needed. Fibrosis occurs due to the repair process of damaged hepatic tissue, which eventually leads to scarring. The innate immune response against HCV is essential in the initiation and progression of liver fibrosis. HCV-infected hepatocytes and liver macrophages secrete proinflammatory cytokines and chemokines that promote the activation and differentiation of hepatic stellate cells (HSCs) to myofibroblasts that produce extracellular matrix (ECM) components. Prolonged ECM production by myofibroblasts due to chronic inflammation is essential to the development of fibrosis. While no antifibrotic therapy is approved to date, several drugs are being tested in phase 2 and phase 3 trials with promising results. This review discusses current state-of-the-art knowledge on treatments targeting the innate immune system to revert chronic hepatitis C-associated liver fibrosis. Agents that cause liver damage may vary (alcohol, virus infection, etc.), but fibrosis progression shows common patterns among them, including chronic inflammation and immune dysregulation, hepatocyte injury, HSC activation, and excessive ECM deposition. Therefore, mechanisms underlying these processes are promising targets for general antifibrotic therapies.

Rewiring Host Signaling: Hepatitis C Virus in Liver Pathogenesis

Hepatitis C virus (HCV) is a major cause of liver disease including metabolic disease, fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). HCV induces and promotes liver disease progression by perturbing a range of survival, proliferative, and metabolic pathways within the proinflammatory cellular microenvironment. The recent breakthrough in antiviral therapy using direct-acting antivirals (DAAs) can cure >90% of HCV patients. However, viral cure cannot fully eliminate the HCC risk, especially in patients with advanced liver disease or comorbidities. HCV induces an epigenetic viral footprint that promotes a pro-oncogenic hepatic signature, which persists after DAA cure. In this review, we summarize the main signaling pathways deregulated by HCV infection, with potential impact on liver pathogenesis. HCV-induced persistent signaling patterns may serve as biomarkers for the stratification of HCV-cured patients at high risk of developing HCC. Moreover, these signaling pathways are potential targets for novel chemopreventive strategies.

Histological and biochemical evaluation of transforming growth factor-β activation and its clinical significance in patients with chronic liver disease

Transforming growth factor-β (TGF-β) is a key driver for liver fibrogenesis. TGF-β must be activated in order to function. Plasma kallikrein (PLK) is a TGF-β activator that cleaves the latency-associated protein (LAP) between arginine⁵⁸ and lysine⁵⁹ residues and releases active TGF-β from the latent TGF-β-LAP complex. Thus, the generation of two LAP degradation products, ending at arginine⁵⁸ (R⁵⁸/LAP-DPs) and beginning from lysine⁵⁹ (L⁵⁹/LAP-DPs), reflects PLK-dependent TGF-β activation. However, the significance and details of TGF-β activation in patients with chronic liver disease (CLD) remain uncertain. We herein examined the PLK-dependent TGF-β activation in patients by detecting R⁵⁸ and L⁵⁹/LAP-DPs. A total of 234 patients with CLD were included in this study. Liver biopsy specimens were used for immunostaining to detect R⁵⁸/LAP-DPs, while plasma samples were subjected to an enzyme-linked immunosorbent assay to measure the L⁵⁹/LAP-DP concentration. R⁵⁸/LAP-DP was robustly expressed in and around the sinusoidal cells before the development of the fibrous regions. The R⁵⁸/LAP-DP expression at fibrosis stage 1 was higher than at any other stages, and the relationship between the plasma L⁵⁹/LAP-DP level and the stage of fibrosis also showed a similar trend. The abundance of plasma L⁵⁹/LAP-DP showed no correlation with the levels of direct serum biomarkers of liver fibrosis; however, its changes during interferon-based therapy for chronic hepatitis C were significantly associated with virological responses. Our results suggest that PLK-dependent TGF-β activation occurs in the early stages of fibrosis and that its unique surrogate markers, R⁵⁸ and L⁵⁹/LAP-DPs, are useful for monitoring the clinical course of CLD.

Hepatitis C virus core protein modulates several signaling pathways involved in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer, and hepatitis C virus (HCV) infection plays a major role in HCC development. The molecular mechanisms by which HCV infection leads to HCC are varied. HCV core protein is an important risk factor in HCV-associated liver pathogenesis and can modulate several signaling pathways involved in cell cycle regulation, cell growth promotion, cell proliferation, apoptosis, oxidative stress and lipid metabolism. The dysregulation of signaling pathways such as transforming growth factor β (TGF-β), vascular endothelial growth factor (VEGF), Wnt/β-catenin (WNT), cyclooxygenase-2 (COX-2) and peroxisome proliferator-activated receptor α (PPARα) by HCV core protein is implicated in the development of HCC. Therefore, it has been suggested that this protein be considered a favorable target for further studies in the development of HCC. In addition, considering the axial role of these signaling pathways in HCC, they are considered druggable targets for cancer therapy. Therefore, using strategies to limit the dysregulation effects of core protein on these signaling pathways seems necessary to prevent HCV-related HCC.

Effect of antiviral treatment of chronic hepatitis C on the frequency of regulatory T cells, T-cell activation, and serum levels of TGF-beta

The aim was to analyze T-regulatory cells (Tregs), activated CD8(+) T cells, and transforming growth factor-beta (TGF)-β in hepatitis C patients. We enrolled 31 patients with chronic genotype 1 hepatitis C virus (HCV) infection, 30 seropositive persons with spontaneous HCV elimination, and 23 healthy volunteers. The patients were examined at the beginning of the interferon-alpha (IFN-α)-based therapy (baseline) and at weeks 4 (W4) and 12 (W12) of the therapy. The percentage of Tregs and the expression of activation markers CD38 and HLA-DR on CD8(+) T cells were analyzed in the peripheral blood by flow cytometry. Serum levels of TGF-β were measured in a multiplex assay using flow cytometry. The percentage of Tregs in patients was higher than in controls and seropositive persons. Similarly, the percentage of CD8(+) T cells expressing CD38 and HLA-DR was higher in patients compared with controls and seropositive persons. Chronic HCV infection is associated with elevated circulating Tregs and activated CD8(+) T cells. During IFN-α-based therapy these cells gradually increase, whereas TGF-β serum levels decrease.

Changes in serum transforming growth factor-β1 levels in chronic hepatitis C patients under antiviral therapy

BACKGROUND

Several cytokines including transforming growth factor (TGF)-β1 have been suggested to be involved in the pathogenesis of fibrosis in chronic hepatitis C. We examined the changes of TGF-β1 serum levels and their predictive value in patients with chronic hepatitis C under antiviral therapy.

METHODS

We included 84 patients with chronic hepatitis C who were treated with pegylated interferon-α and ribavirin between 2008 and 2009. Treatment was given for 24-48 weeks depending on HCV genotype. Serum TGF-β1 levels were measured by an ELISA assay at baseline, at the end of therapy (EOT), and at 6 months after the EOT. Liver fibrosis was evaluated by transient elastography.

RESULTS

Of the 84 patients, 76.2% achieved sustained virological response (SVR), 8.3% responded at the EOT but relapsed during post-therapy follow up (RR) and 15.5% had no response (NR). In all patients, mean TGF-β1 levels were 16,980 pg/mL at baseline and decreased significantly at EOT (12,041 pg/mL) and at 6 months of post-treatment follow up (13,254 pg/mL) (P≤0.001). In particular, mean TGF-β1 levels decreased significantly from baseline to EOT and to six months of post-treatment follow up in patients with SVR and numerically but not significantly in patients with RR or NR. TGF-β1 levels were not associated with the severity of liver stiffness estimated by transient elastography.

CONCLUSION

Our data show that TGF-β1 serum levels decrease significantly at the EOT and remain decreased 6 months after the EOT mostly in chronic hepatitis C patients who achieve SVR after pegylated interferon-α and ribavirin combination treatment.

Overexpression of cyclooxygenase-2 and transforming growth factor-beta 1 is an independent predictor of poor virological response to interferon therapy in chronic HCV genotype 4 patients

BACKGROUND/AIMS

COX-2 and TGF-β1 are overexpressed in hepatitis C virus (HCV) infection and are related to hepatitis pathogenesis and hepatic fibrosis. The current study investigated the relationship between pretreatment COX-2 and TGF-β1 hepatic expression in HCV genotype 4 and the virological response to interferon therapy.

PATIENTS AND METHODS

Liver biopsies of 55 patients with HCV infection genotype 4 were selected together with 10 liver biopsies as control. The patients' clinicopathological data were collected. Immunohistochemistry was done using anti-COX-2 and anti-TGF-β1 antibodies. Statistical tests were used to determine the association between both COX-2 and TGF-β1 expression in relation to clinicopathological parameters and response to interferon therapy.

RESULTS

COX-2 was upregulated especially in nonresponders and was an independent predictor of poor virological response. However, COX-2 showed no association with other clinicopathological features. TGF-β1 was upregulated and associated with nonresponders, histological activity, and fibrosis stage. There was no association between TGF-β1 and other clinicopathological features. There was an association between COX-2 and TGF-β1 immunoexpression.

CONCLUSION

Overexpression of COX-2 and TGF-β1 is an independent predictor for poor outcome of interferon and ribavirin therapy and these might be useful markers for the response to treatment. Both molecules are associated together; however, their role during hepatitis treatment has to be clarified.

Parallel microRNA and mRNA expression profiling of (genotype 1b) human hepatoma cells expressing hepatitis C virus

BACKGROUND & AIMS

MicroRNAs (miRNAs) are members of a class of small noncoding functional RNAs that modulate gene regulation at the post-transcriptional level in a sequence specific manner. miRNA dysfunction has been linked to the pathophysiology of human diseases including those resulting from viral infections. The objective of this study was to investigate changes in miRNA profiles that occur in hepatoma cells expressing hepatitis C virus (HCV) and identify anticorrelated mRNAs, which may be their regulatory targets.

METHODS

Microarrays were used to perform global miRNA and mRNA expression analysis. Fold changes and pairwise statistics were computed for the resulting datasets. Hierarchical cluster and pathway analyses were performed to assess the degree of differential expression and identify regulatory networks. Bioinformatics tools were used to integrate mRNA profiling results with miRNA target predictions.

RESULTS

Replication of the Con1 strain of HCV virus in hepatoma cells elicited extensive differential expression of both miRNAs and mRNAs. Forty-three differentially expressed miRNAs (P≤0.001) were identified by microarray analysis in HCV expressing cells. Six thousand eight hundred and fifteen differentially expressed mRNAs (P≤0.05) were identified. Computational analyses revealed anticorrelated miRNA:mRNA pairs for each target prediction algorithm used. Pathway analysis generated a filtered pathway with 120 entities, including seven major regulators and nine major targets potentially under the control of at least 11 miRNAs.

CONCLUSIONS

The expression of a number of anticorrelated miRNAs:mRNA pairs are affected by the presence of HCV. These miRNAs and their putative targets are attractive candidates for being involved in the pathogenesis and/or progression of HCV-induced chronic hepatitis.

Angiogenic cytokines in patients undergoing antiviral treatment for chronic hepatitis C virus infection

During chronic liver disease (CLD), angiogenesis participates in the fibrogenic process. Herein, we aimed at verifying the on-treatment kinetics of serum vascular endothelial growth factor (VEGF) and angiopoietin-2 (Ang-2) in hepatitis C virus (HCV) patients undergoing antiviral therapy. Forty-three HCV patients treated with pegylated-interferon/ribavirin and 26 controls were studied. Serum VEGF and Ang-2 were determined before treatment, at different time points during treatment, and at follow-up after treatment. Thirty and 13 patients were sustained virological responder (SVR) and No-SVR, respectively. Patients showed increased Ang-2 levels [504 (368-720) versus 449 (389-483) pg/mL, P < 0.05], and equivalent VEGF levels [271 (193-377) versus 274 (199-324) pg/mL, P = 0.6], with respect to controls. By univariate analysis, stage of fibrosis was associated with Ang-2 levels (odds ratio 4.25, P < 0.05). In SVR patients VEGF levels showed a progressive reduction (P < 0.05) but returned to pretherapy levels at follow-up, and Ang-2 levels showed an opposite progressive increase, being significantly reduced at follow-up (P < 0.01). No significant modifications in VEGF and Ang-2 levels were observed in No-SVR. We conclude that, in patients with HCV-CLD, Ang-2 serum levels are associated with fibrosis and reduced at follow-up in SVR patients. On-treatment, VEGF and Ang-2 serum levels undergo different-sided modifications only in SVR patients, possibly expressing the vascular remodeling occurring early after viral clearance.

TGF-beta plasma levels in chromoblastomycosis patients during itraconazole treatment

BACKGROUND

Chromoblastomycosis (CBM) is a dermal mycosis. The disease evolves to a chronic state, presenting a suppurative granulomatous dermatitis, combined with variable dermal fibrosis. Pathogenesis of the inflammation and tissue repair in CBM are poorly understood.

AIM

To quantify Transforming Growth Factor-beta (TGF-beta) plasma levels of CBM patients during itraconazole (ITZ) treatment.

METHODS

Blood plasma of 12 CBM patients was subjected to TGF-beta titration with ELISA at 0, 3, 6 and 12months of 200mg per day of ITZ therapy, and correlated with the clinical aspects. Plasma of 12 healthy individuals were used for control.

RESULTS

CBM patients present high plasma levels of TGF-beta (7.016+/-1988pg/ml), decreasing after 03months (4.625+/-645pg/ml) of ITZ treatment, which correlates with a rapid clinical improvement. However, after 6 (6.566+/-777pg/ml) and 12months (6.908+/-776) of treatment, TGF-beta levels increase to almost the same levels observed before treatment, which is related to a slow clinical improvement, fungal persistence on the lesion, and fibrotic scars.

CONCLUSION

TGF-beta plasma levels are high in CBM patients. Fungal destruction by ITZ correlates with TGF-beta downregulation, but tissue remodeling and fungal persistence probably raises its levels again, interfering with cellular immune responses.

Thrombopoietin is ineffective in a mouse model of motor neuron disease

This study assessed the therapeutic efficacy of thrombopoietin (TPO) in the mouse model of ALS using two treatment paradigms. TPO was administered either daily or in 13-day treatment cycles to SOD1-G93A mice. Quantitative analysis of platelet levels, VEGF and TGF-beta1 trophic factors were assessed. The effect of TPO on disease progression was analyzed by behavioral analysis and clinical examination. TPO treatment increased levels of platelets and TGF-beta1 but not VEGF. This treatment did not affect onset or survival in these mice. Although biologically active, demonstrated by increased platelet and TGF-beta1 levels, rmTPO did not attenuate disease progression in ALS mice.

Can serum TGF-beta 1 be used to evaluate the response to antiviral therapy of haemophilic patients with HCV-related chronic hepatitis?

Congenital coagulation disorders limit the use of liver biopsy, especially when repeated assessment is needed. TGF-beta 1 plays a pivotal role in inducing fibrosis and has been proposed as its surrogate marker. Aiming at validating the clinical utility of this cytokine, fifteen haemophilic patients suffering from HCV-related chronic hepatitis were treated with Peg-IFN alpha2beta plus Ribavirin. Serum TGFbeta 1, viral load and liver enzymes were analyzed at baseline and at six, twelve, and eighteen months. As expected, patients initially showed significantly higher TGF-beta 1 levels than age-matched controls (43.8 ng/mL, 28.7-46.4 vs. 26.9 ng/mL, 23.0-34.0, median and 95% CI; p=0.004). The end of therapy response rate was 67%. The main finding was a significant drop in TGF-beta 1 at six months compared to baseline values; this drop de facto predicted the levels reached in the following six months, which were fixed at lower concentrations (37.0 ng/mL, 21.9-43.8 and 27.0 ng/mL, 24.1-44.0 respectively; p<0.009), independently of treatment outcome (three patients were breakthrough, twelve were sustained virological responders (SVRs). During the treatment period none had clinical or biochemical signs of inflammation in other areas. Treatment was followed by a six-month follow-up, at the end of which TGF-beta 1 was increased compared to the previous values, reaching the initial levels in ten SVRs (45 ng/mL, 24.5-52.9). Interestingly, at a longer follow-up, two out of ten SVRs, who displayed the highest values of TGF-beta 1, relapsed. Serum TGF-beta 1 could be used to assess therapeutic outcome and short-term prognosis of HCV-related chronic hepatitis.

Hepatic stellate cell activation in liver transplant patients with hepatitis C recurrence and in non-transplanted patients with chronic hepatitis C

The pathogenic mechanisms of accelerated graft fibrosis in hepatitis C recurrence after liver transplantation (LT) are not well established. The aim of the study was to assess whether a greater activation of hepatic stellate cells (HSC), the major collagen-producing cells in the liver, can occur in these patients as compared to non-LT patients with chronic hepatitis C. We determined the amount of activated HSC by computer-based morphometric analysis of alpha-smooth muscle actin (alphaSMA)-positive cells and the hepatic TGFbeta(1) expression by immunohistochemistry in 46 LT patients with hepatitis C recurrence, 35 non-LT patients with chronic hepatitis C, and 16 controls. Hepatic alphaSMA and TGFbeta(1) expression was higher in LT patients with hepatitis C recurrence than in controls and was correlated with fibrosis stage and progression rate. No significant difference in alphaSMA and TGFbeta(1) expression was observed between LT and non-LT patients with hepatitis C, with the exception of a higher transforming growth factor beta-1 (TGFbeta(1)) expression in non-LT patients in the early stages of fibrosis. LT patients receiving cyclosporine (CsA) or tacrolimus (FK) had a similar fibrosis progression rate and alphaSMA and TGFbeta(1) expression. In conclusion, the accelerated fibrosis observed in LT patients with hepatitis C recurrence does not seem to be related to a greater amount of activated HSC and TGFbeta(1) expression in the grafts of these patients as compared to non-LT patients with chronic hepatitis C. In LT patients, the amount of activated HSC and TGFbeta(1) expression correlated with fibrosis stage and progression, without any apparent influence of the type of calcineurin inhibitor administered.

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