Current Drug Targets - Volume 18, Issue 7, 2017

More than 180 millions of subjects in the world are infected by Hepatitis C Virus (HCV), and about 20% of them with HCV chronic infection progress to cirrhosis. Furthermore, numerous HCV extrahepatic manifestations have been reported in up to 74% of patients, as mixed cryoglobulinemia, lymphomas, rheumatic disorders, autoimmune thyroiditis, hypothyroidism, papillary thyroid cancer, and type 2 diabetes. Advances in understanding the HCV life cycle, and the inflammatory processes (involving a complex network of cytokines and chemokines) associated with HCV chronic infection, have led to substantial advancements in therapy. The combination of ribavirin and PEGylated interferon-α was the standard of therapy for HCV chronically infected patients in the last decades. However, interferon has limited effectiveness and is associated with severe adverse effects. Recently, direct-acting antivirals (DAAs) that act as inhibitors of N5SA, or polymerase, or protease have been shown to result in shorter duration of therapy, better efficacy and tolerance, with respect to ribavirin and PEGylated interferon-α. Circulating CXCL10 levels, and the interleukin(IL)-28B gene polymorphisms, are associated with the success of the therapy both with DAAs or ribavirin and PEGylated interferon-alpha. New DAAs targeting the HCV at various molecular levels have been developed to eradicate HCV. Moving to interferonfree therapies should offer new treatments for resistant HCV genotypes, and for ineligible patients or patients failing to respond to prior therapies. Many efforts have been made to understand the factors that are involved with clearance of HCV to personalize the therapy for each patient, with the aim to reduce side effects, increasing the sustained virologic response rate, and to prevent the progression of the disease.

Hepatitis C virus (HCV) is a worldwide major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). Accumulating evidence indicates that a number of microRNAs (miRNAs), which are able to exert an effect on liver biology and pathology, can regulate or be regulated by HCV infection. Many studies demonstrate that HCV utilizes host miRNAs and modulates expression of miRNAs in infected hepatocytes for its infection and propagation. In turn, host miRNAs can directly regulate HCV replication through interaction with the HCV RNA genome or by indirectly controlling the host pathways associated with the virus replication, which eventually induce HCV-related liver diseases such as liver fibrosis, hepatic cirrhosis, or HCC. Recently, extracellular miRNAs (circulating miRNAs) detected in human serum and plasma are proposed as biomarker candidates for pathological conditions due to their remarkably stable nature and the non-invasiveness of their detection. Since these circulating miRNAs exhibit consistent levels between healthy individuals but significantly changed profiles in disease conditions, considerable effort has been employed to investigate the alteration in the circulating miRNA pattern that is related with HCV infection and associated liver diseases. In this review, we summarize the features of miRNAs critical for HCVassociated liver disease initiation and progress, and discuss growing evidence that distinctive circulating miRNA patterns are related with HCV infection and associated liver diseases. These will shed light on the development of miRNA-based therapeutic modalities and non-invasive biomarkers for the diagnosis and prognosis of HCV infection and associated diseases.

Hepatitis C virus (HCV) is a major cause of liver-related morbidity and is strongly associated with B-cell lymphoproliferative disorders. Data from epidemiological, biological and clinical investigations support the hypothesis of a pathogenetic role of HCV in at least a subgroup of patients with B-cell non-Hodgkin's lymphoma (B-NHL). Morphologically, HCV-associated B-NHL represents a variety of histological subtypes. The comprehension of the mechanisms of HCV persistence and of its role in the lymphomagenesis will be useful to set new strategies with the aim to prevent and treat HCV-associated B-NHLs. This hypothesis of a virus-induced mechanism of lymphomagenesis arises from the growing evidence that successful antiviral treatment is often linked to regression of some types of HCV-related indolent B-NHLs.

Mixed Cryoglobulinemia (MC) is the most frequent extrahepatic manifestation of Hepatitis C virus (HCV) infection. MC is an autoimmune /B-cell lymphoproliferative disorder characterized by circulating immune-complexes, named cryoglobulins. MC patients exhibit symptoms due to a systemic vasculitis of small/medium size vessels (mixed cryoglobulinemia syndrome, MCS) in a percentage going from 5 to 30%. The first-line therapeutic option in MCS patients is the etiologic treatment and, in the past fifteen years, antiviral therapy with Pegylated-Interferon (Peg-IFN) plus Ribavirin (RBV) represented the standard of care. Lately, the arrival of direct acting antivirals (DAAs) significantly modified the cure of HCV infection, consenting the use of IFN-free regimens. Here we report a review of the literature about the role of antiviral treatment, following its evolution, in treating HCVrelated MC. Furthermore, we report the results, after 8 weeks of treatment, of a preliminary pilot prospective study, counting 17 patients with HCV-related MC with or without MCS, treated with new generation DAAs in IFN-free regimens. After 8 weeks of DAA administration, all the subjects were HCV RNA negative. Moreover, in 6/17 (35%) patients cryoglobulins disappeared and, on the whole, in all patients a decrease of the cryocrit values was observed (p<0.05). Furthermore, three MCS-HCV patients (30%) resulted to be complete clinical responders and 5 subjects (50%) partial clinical responders. Therefore, IFN-free anti-HCV treatment appears to be safe and effective in MC patients from virological and clinical points of view, thus supporting the importance of HCV eradication in leading MC remission.

Cytokines and chemokines, hepatitis C virus (HCV) infection-induced, participate in viral control and liver damage. The complex cytokine network, operating during initial infection allows a coordinated and effective development of innate and adaptive immune responses. “HCV interferes with cytokines at various levels and escapes immune response by inducing a T helper (Th)2/T cytotoxic 2 cytokine profile”. A predominance of the Th1 immune response (and related cytokines) has been evidenced in chronic hepatitis C infection and in extrahepatic manifestations. Interferon (IFN)-γ and IFN-γ-inducible chemokine (C-X-C motif) ligand (CXCL)9, -10 and -11 recruit inflammatory infiltrates into the liver parenchyma due to the incapability to control the infection process, resulting in extensive liver damage and liver cirrhosis. “The most important systemic HCV-related extrahepatic diseases — mixed cryoglobulinemia, lymphoproliferative disorders, diabetes and autoimmune thyroid disorders — are associated with a complex dysregulation of the cytokine/chemokine network and involve pro-inflammatory and Th1 chemokines. The therapeutical administration of cytokines such as IFN-α may result in viral clearance during persistent infection and reverts this process” reducing circulating CXCL10 levels. “Several studies have reported interleukin (IL)-28B polymorphisms, and circulating CXCL10, may be prognostic markers for HCV treatment efficacy in HCV infection”. Other studies have also shown that HCV clearance by directly acting antiviral agents therapy decreases circulating CXCL10 levels. “Theoretically agents that selectively neutralize CXCL10 could increase patient responsiveness to traditional IFN-based HCV therapy”, simultaneously reducing inflammatory immune cell activation.

Mixed cryoglobulinemia syndrome (MCs) is a systemic vasculitis, involving skin, joints, peripheral nerves, and several internal organs. Hepatitis C virus (HCV) is recognized as the etiologic agent for the majority of MCs patients, as well as of number of autoimmune, lymphoproliferative, and neoplastic disorders. In this context, HCV-related MCs represents an important model autoimmune/ neoplastic disease triggered by a virus in humans. With regard the therapeutic strategies of MCs, we can treat these patients at different steps by means of etiological (antivirals), pathogenetic, symptomatic drugs (mainly immunosuppressors, corticosteroids, plasmapheresis). In the majority of individuals, MCs shows a mild, slow-progressive clinical course needing only symptomatic treatments, generally low doses of corticosteroids. Considering the etiopathogenesis of MCs, the eradication of HCV should be considered the gold standard in the treatment of MCs. The use of combined peg-interferon- α/ribavirin and/or novel antiviral drugs may lead to HCV eradication in a significant percentage of cases with possible remission of MCs. On the other hand, the presence of rapidly progressive, diffuse vasculitis with multiple organ involvement may be successfully treated with aggressive immunosuppressive and anti-inflammatory therapies, mainly based on cyclophosphamide or rituximab, high dose corticosteroids, and plasma aphaeresis. Moreover, sequential/combined antiviral or immunosuppressive treatments could represent an useful therapeutic strategy particularly in MCs patients with major clinical manifestations. The treatment of MCs should be decided for every patient according to the severity of clinical picture. Thus, a careful follow-up of the disease is necessary, with particular attention to the possibility of cancers onset, such as B-cell lymphoma. The present review focuses on the different therapeutic strategies in patients with MCs, including the treatment of cryoglobulinemic skin ulcers, which represents one of the most discouraging complications of the disease.

A number of hepatic and extra-hepatic autoimmune disorders may complicate a percentage of patients with hepatitis C virus (HCV) infection that is both hepatotropic and lymphotropic agent; the resulting clinical phenotypes can be grouped into the so-called HCV syndrome. This latter includes various rheumatic disorders that are frequently characterized by clinical or serological overlap; thus, a correct patients’ classification is necessary prior to decide the therapy. The management of these conditions is particularly difficult, given the coexistence of viral infection and immunological alterations. In this scenario, cryoglobulinemic vasculitis represents the prototype of HCV-related rheumatic disorders that can be treated at different levels by means of etiological (antivirals) and/or pathogenetic and/or symptomatic treatments (rituximab, cyclophosphamide, steroids, plasmapheresis, etc). In clinical practice, the therapeutic strategy should take into account the specific symptoms combination and the severity/activity of the disease, according to each patient’s conditions. This review focuses on the clinico-diagnostic assessments and therapeutical approaches of some rheumatic disorders complicating HCV infection, mainly arthritis, sicca syndrome, and osteosclerosis; while, cryoglobulinemic vasculitis is comprehensively examined in another article of the present issue.

We have entered a new era of hepatitis C virus (HCV) therapy in which elimination of infection and disease is a real possibility. HCV cell culture models were instrumental for identification of therapeutic targets, testing candidate drugs, and profiling of therapeutic strategies. Here we describe current and novel methods of cell culture systems for HCV that are allowing investigation of HCV life cycle and virus-host interaction required for replication and propagation. The development of protocols to grow infectious virus in culture and generate hepatocyte cell lines from specific individuals hold great promise to investigate the mechanisms exploited by the virus to spread the infection and the host factors critical for HCV replication and propagation, or resistance to infection. Since host factors are presumably conserved and equally interacting with different HCV isolates and genotypes, the development of drugs targeting host factors essential for virus replication holds great promises in further increasing treatment efficacy. Refocusing of therapeutic goals also impacted in vitro diagnosis. The primary goal of anti-HCV therapy is to achieve a sustained virologic response (SVR) defined as “undetectable” HCV RNA genome in the serum or plasma at 12 to 24 weeks following the end of treatment. Use of direct antiviral agents has substantially changed the threshold of the viral load used to define SVR and led to a reassessment, as discussed herein, of result interpretation and requirements of clinically-approved, quantitative molecular assays.

Hepatitis C virus (HCV) remains a public health problem of global importance, even in the era of potent directly-acting antiviral drugs. In this chapter, I discuss immune responses to acute and chronic HCV infection. The outcome of HCV infection is influenced by viral strategies that limit or delay the initiation of innate antiviral responses. This delay may enable HCV to establish widespread infection long before the host mounts effective T and B cell responses. HCV's genetic agility, resulting from its high rate of replication and its error prone replication mechanism, enables it to evade immune recognition. Adaptive immune responses fail to keep up with changing viral epitopes. Neutralizing antibody epitopes may be hidden by decoy structures, glycans, and lipoproteins. T cell responses fail due to changing epitope sequences and due to exhaustion, a phenomenon that may have evolved to limit immune-mediated pathology. Despite these difficulties, innate and adaptive immune mechanisms do impact HCV replication. Immune-mediated clearance of infection is possible, occurring in 20-50% of people who contract the disease. New developments raise hopes for effective immunological interventions to prevent or treat HCV infection.

It is known that the production of and/or response to interferon (IFN) are deregulated during chronic hepatitis C virus (HCV) infection. In particular, several studies have shown that patients with chronic HCV infection who have a high natural level of IFN-stimulated genes (ISGs) do not achieve viral clearance and have a poor response to treatment with pegylated IFNα and ribavirin. The viral and/or host factors that are responsible for the higher endogenous ISGs expression in some HCV infected patients compared to others remain to be determined. However, type III IFNs, and in particular the new discovered IFN lambda (L) 4 Gene, appear to play a dominant role in driving ISGs response and in contributing to the establishment of HCV persistence. This review focuses on recent studies on how the ISGs response and the IFNλ genetic factors (interleukin-28B and IFNL4) affect the clinical outcome of HCV infection highlighting their impact in the current antiviral therapies with direct acting antiviral agents.

Treatment for hepatitis C virus (HCV) infection has progressed at remarkable speed. From poorly tolerated injectable therapy with very low cure rates, treatment has moved to highly effective well-tolerated all oral direct-acting antiviral therapies with cure rates above 90% for almost all patients populations. Direct-acting antivirals have developed out of an improved understanding of the viral lifecycle with recognition of targets that could be inhibited by small molecules. To date protease inhibitors, non-structural 5a inhibitors and nucleotide and non-nucleotide polymerase inhibitors have been developed. These agents have been used initially with peginterferon and ribavirin and subsequently in combination without the need for interferon. Rational combinations have overcome the major challenge of rapid emergence of drug resistance and second-generation agents in each class have improved safety and efficacy profiles with fewer drug-drug interactions and very few adverse effects. The progress of direct-acting antiviral development is outlined with a review of each class of agent as well as a discussion of challenges for the future.

A complex network of different cytokines and chemokines modulates atherosclerosis, a chronic inflammatory disease. Interleukin-17A (IL-17A) is expressed by different leukocyte subsets such as CD4+IL-17+ T cells (Th17), γδ T cells, natural killer cells, natural killer T cells, and neutrophils. IL-17A plays an important role in host defense and is involved in the pathology of different autoimmune and inflammatory diseases. Recent studies demonstrate an association of IL-17A with atherosclerosis. IL-17A seems to have primarily pro-inflammatory effects in atherogenesis, although there are partially controversial results in the literature. In the murine system, several studies indicate a pro-atherogenic role of IL-17A mediated by increased migration of leukocytes (especially macrophages) into atherosclerotic lesions, increased expression of pro-inflammatory cytokines and chemokines as well as plaque destabilizing matrix-metalloproteinases using Apoe-/-and LDLr-/-mice. In contrast, three studies show atheroprotective effects of IL-17A mediated by downregulation of aortic VCAM-1 expression on endothelial cells and increased collagen production by vascular smooth muscle cells (VSMCs) in LDLr-/-mice. In humans, expression of IL-17A was associated with increased inflammation and plaque vulnerability in human atherosclerotic lesions. Moreover, IL-17A induced a pro-inflammatory, pro-thrombotic, plaque-destabilizing, and cell-attracting response of the inflammatory milieu of human plaque tissue samples. Notably, a recently published study challenged these findings by showing a worse outcome of patients with acute myocardial infarction with low serum levels of IL-17A. In the following review, we will focus on the recent progress of functional studies of IL-17A in atherosclerosis and will try to collect explanations for the controversial data.

Alpha-fetoprotein (AFP) is a 69 kD fetal- and tumor-associated single-chain glycoprotein belonging to the albuminoid gene family. AFP functions as a carrier/transport molecule as well as a growth regulator and has been utilized as a clinical biomarker for both fetal defects and cancer growth. Lysophospholipids (LPLs) are plasma membrane-derived bioactive lipid signaling mediators composed of a small molecular weight single acyl carbon chain (palmitic, oleic acid) attached to a polar headgroup; they range in molecular mass from 250-750 daltons. The LPLs consist of either sphingosine-1-phosphate or lysophosphatidic acid, and mostly their choline, ethanolamine, serine or inositol derivatives. They are present only in vertebrates. These bioactive paracrine lipid mediators are ubiquitously distributed in tissues and are released from many different cell types (platelets, macrophages, monocytes, etc.) involved in developmental, physiological, and pathological processes. The LPLs bind to four different classes of G-protein coupled receptors described herein which transduce a multiple of cell effects encompassing activities such as morphogenesis, neural development, angiogenesis, and carcinogenesis. The identification of potential binding sites of LPL receptors on the AFP third domain receptor binding fragment was derived by computer modeling analysis. It is conceivable, but not proven, that AFP might bind not only to the LPL receptors, but also to LPLs themselves since AFP binds medium and long chain fatty acids. It is proposed that some of the activities ascribed to AFP in the past might be due in part to the presence of bound LPLs and/or their receptors.