Recent Advances in Antiviral Therapy for Chronic Hepatitis C

Bothropstoxins I and II as potent phospholipase A2 molecules from Bothrops jararacussu to impair Hepatitis C virus infection

Hepatitis C is a hepatological disorder induced by the Hepacivirus hominis (Hepatitis C virus, HCV), with approximately 170 million individuals estimated to be presently affected globally. The current treatment for infected patients primarily relies on direct-acting antivirals (DAAs). However, this treatment is marked by its high cost, numerous side effects, and documented instances of antiviral resistance. These challenges underscore the imperative for developing novel therapeutic strategies. In this framework, naturally occurring compounds have exhibited considerable medical significance attributable to their biological functionalities. Compounds extracted from snake venoms have evidenced antiviral efficacy against a variety of viral pathogens including Orthoflavivirus denguei (DENV), Orthoflavivirus flavi (YFV), Orthoflavivirus zikaense (ZIKV), and HCV. Here, the activity of 10 proteins isolated from snakes' venom of Bothrops genus were evaluated against HCV replicative cycle. The full-length JFH-1 HCV system was used to infect the Huh-7.5 cell. Cell viability was measured simultaneously through MTT assay. Eight compounds inhibited up to 99% of HCV infection, being the most potent inhibitory rates observed in BthTX-I and BthTX-II, with an SI of 13.5 and 1736, respectively, being able to block 84.7% and 96% of HCV infectivity, in the same order. BthTX-II also demonstrated a protective effect in cells treated prior to HCV infection of approximately 86.7%. Molecular docking calculations suggest interactions between the two proteins with HCV E1-E2 glycoprotein complex. BthTX-II exhibited stronger interactions, indicated by 22 hydrophobic interactions. In conclusion, these compounds were shown to inhibit HCV infectivity by either acting on the virus particles or protecting the cells against infection.

Nanomedicine for the Treatment of Viral Diseases: Smaller Solution to Bigger Problems

The continuous evolution of new viruses poses a danger to world health. Rampant outbreaks may advance to pandemic level, often straining financial and medical resources to breaking point. While vaccination remains the gold standard to prevent viral illnesses, these are mostly prophylactic and offer minimal assistance to those who have already developed viral illnesses. Moreover, the timeline to vaccine development and testing can be extensive, leading to a lapse in controlling the spread of viral infection during pandemics. Antiviral therapeutics can provide a temporary fix to tide over the time lag when vaccines are not available during the commencement of a disease outburst. At times, these medications can have negative side effects that outweigh the benefits, and they are not always effective against newly emerging virus strains. Several limitations with conventional antiviral therapies may be addressed by nanotechnology. By using nano delivery vehicles, for instance, the pharmacokinetic profile of antiviral medications can be significantly improved while decreasing systemic toxicity. The virucidal or virus-neutralizing qualities of other special nanomaterials can be exploited. This review focuses on the recent advancements in nanomedicine against RNA viruses, including nano-vaccines and nano-herbal therapeutics.

The long and stumble way to find potential active compounds from plants for defeating hepatitis B and C: review

Hepatitis is a liver illness caused by virus such as hepatitis A virus, hepatitis B virus and hepatitis C virus. Hepatitis B and C are considerably more usual and induce more cirrhosis and dead worldwide than hepatitis A. Although drugs that are currently often used in the medication of hepatitis B and C, the finding of recent drug from various resources including herbal has been intensively developed. Therefore, the purpose of this review is to consider the possibility of plant’s compounds as anti-HBV and anti-HCV. From the results of a review of several articles, several plant’s compound have shown effectiveness againts HBV and HCV by in silico, in vitro and in vivo studies. In conclusion, several plant’s active compounds are possibility to be developed as anti-hepatitis B and C.

Successful treatment of hepatitis C genotype 4 using sofosbuvir, daclatasvir, simeprevir and ribavirin in Egyptian patients with direct-acting antiviral agent treatment failure

Introduction

In chronic hepatitis C virus (HCV) patients in whom prior direct-acting antiviral agent (DAA) treatment had failed, outcomes after retreatment are optimal. Combination of sofosbuvir (SOF), daclatasvir (DCV), simeprevir (SIM), and ribavirin (RBV) in treatment experienced patients is recommended in current guidelines despite insufficient data. Our aim is to determine the efficacy and safety of SOF, DCV, SIM plus RBV in HCV infected patients who failed prior DAA treatment.

Material and methods

One hundred and seventeen patients who failed to respond to SOF containing regimens were randomized according to previous response to therapy to non-responders and relapsers. Duration of therapy depends on fibrosis stages. SOF, DCV, SIM and weight based RBV 12 weeks for F1 and F2 (group I) and 24 weeks for F3 and F4 (group II).

Results

In the non-responder group, a sustained virologic response (SVR) occurred in 100% in group I (F1 and F2) and 97% in group II (F3 and F4). Relapse was 3% in group II (F3 and F4). No patients from either group had breakthrough or non-response. In relapsers SVR was 100% in group I (F1 and F2) and 96% in group II (F3 and F4). Breakthrough, relapse and non-response were 2%, 4%, 2% respectively only in group II (F3 and F4).

Conclusions

Combining multiple DAAs with different viral targets may be effective treatment protocol in previous non-responders and relapsers with short durations of treatment.

An in vitro study of an Artocarpus heterophyllus substance as a hepatitis C antiviral and its combination with current anti-HCV drugs

Background

Current therapy of chronic hepatitis C virus (HCV) with direct-acting antivirals (DAAs) has dramatically improved the sustained virologic response (SVR) of affected patients; however, treatment with DAAs remains expensive, and drug-resistant HCV variants remain a threat. As a result, there is still a need to continue to develop affordable and effective drugs for the treatment of HCV. Previously, we have demonstrated that a crude extract from Artocarpus heterophyllus leaves is a potential anti-HCV candidate. In this study, we have further purified this crude extract, examined which sub-fraction possesses the highest antiviral activity, and then explored its efficacy at different HCV life cycle stages. We also assessed synergistic antiviral effects between the A. heterophyllus extract and commercially available anti-HCV drugs.

Methods

We used vacuum liquid chromatography (VLC) and high-performance liquid chromatography (HPLC) to fractionate a dichloromethane extract of A. heterophyllus leaves. We then examined the anti-HCV activity of the fractions using HCV genotype 2a, JFH1a; the antiviral mode of action was determined by exploring adding the treatments at different times. We examined the antiviral effects on the viral entry stage through a virucidal activity test, viral adsorption examination, and pretreatment of cells with the drug. The effects on the post-viral entry stage were determined by the levels of HCV protein expression and HCV RNA expression in infected cells.

Results

Through activity guided purification, we identified the sub-fraction FR3T3 as possessing the most robust anti-HCV activity with an IC₅₀ value of 4.7 ± 1.0 μg/mL. Mode-of-action analysis revealed that FR3T3 inhibited post-viral entry stages such as HCV NS3 protein expression and HCV RNA replication with marginal effects on the viral entry stage. Thin-layer Chromatography (TLC) indicated that FR3T3 contained terpenoids and chlorophyll-related compounds. We also found a synergistic antiviral activity when the DCM extract of A. heterohyllus was used in combination therapy with commercial anti-HCV drugs; Ribavirin, Simeprevir, Cyclosporin A.

Conclusions

The extract of A. heterophyllus and its sub-fraction, FR3T3, presented here have anti-HCV activities and could be candidate drugs for add-on-therapy for treatment of chronic HCV infections.

Nanomedicine as a promising strategy for the theranostics of infectious diseases

Infectious diseases caused by bacteria, viruses, and fungi and their global spread pose a great threat to human health. The 2019 World Health Organization report predicted that infection-related mortality will be similar to cancer mortality by 2050. Particularly, the global cumulative numbers of the recent outbreak of coronavirus disease (COVID-19) have reached 110.7 million cases and over 2.4 million deaths as of February 23, 2021. Moreover, the crisis of these infectious diseases exposes the many problems of traditional diagnosis, treatment, and prevention, such as time-consuming and unselective detection methods, the emergence of drug-resistant bacteria, serious side effects, and poor drug delivery. There is an urgent need for rapid and sensitive diagnosis as well as high efficacy and low toxicity treatments. The emergence of nanomedicine has provided a promising strategy to greatly enhance detection methods and drug treatment efficacy. Owing to their unique optical, magnetic, and electrical properties, nanoparticles (NPs) have great potential for the fast and selective detection of bacteria, viruses, and fungi. NPs exhibit remarkable antibacterial activity by releasing reactive oxygen species and metal ions, exerting photothermal effects, and causing destruction of the cell membrane. Nano-based delivery systems can further improve drug permeability, reduce the side effects of drugs, and prolong systemic circulation time and drug half-life. Moreover, effective drugs against COVID-19 are still lacking. Recently, nanomedicine has shown great potential to accelerate the development of safe and novel anti-COVID-19 drugs. This article reviews the fundamental mechanisms and the latest developments in the treatment and diagnosis of bacteria, viruses, and fungi and discusses the challenges and perspectives in the application of nanomedicine.

Elbasvir and grazoprevir for the treatment of hepatitis C

Introduction: Hepatitis C is one of the leading causes of chronic liver disease. The direct-acting-antivirals has revolutionized the chronic hepatitis C treatment. DAAs can achieve a sustained virological response rate >95% in different populations.Area covered: This review summarizes the pharmacokinetics, pharmacodynamics, efficacy, and safety of Elbasvir/Grazoprevir (EBR/GZR).Expert opinion: EBR/GZR is a combination of NS5A and NS3/4A inhibitors. The performance in the EBR/GZR combination's safety and tolerability is appreciated in clinical treatment. EBR/GZR also has a higher barrier to resistance-associated substitutions. Based on clinical trials and real-world experience, elbasvir/grazoprevir is effective in the HCV GT1, 4 infections.

Nanotechnology for virus treatment

The continued emergence of novel viruses poses a significant threat to global health. Uncontrolled outbreaks can result in pandemics that have the potential to overburden our healthcare and economic systems. While vaccination is a conventional modality that can be employed to promote herd immunity, antiviral vaccines can only be applied prophylactically and do little to help patients who have already contracted viral infections. During the early stages of a disease outbreak when vaccines are unavailable, therapeutic antiviral drugs can be used as a stopgap solution. However, these treatments do not always work against emerging viral strains and can be accompanied by adverse effects that sometimes outweigh the benefits. Nanotechnology has the potential to overcome many of the challenges facing current antiviral therapies. For example, nanodelivery vehicles can be employed to drastically improve the pharmacokinetic profile of antiviral drugs while reducing their systemic toxicity. Other unique nanomaterials can be leveraged for their virucidal or virus-neutralizing properties. In this review, we discuss recent developments in antiviral nanotherapeutics and provide a perspective on the application of nanotechnology to the SARS-CoV-2 outbreak and future virus pandemics.

2020 Taiwan consensus statement on the management of hepatitis C: part (I) general population

Hepatitis C virus (HCV) infection remains a major public health issue with high prevalence in Taiwan. Recently, the advent of direct-acting antiviral (DAA) agents, with higher efficacy, excellent safety profile, and truncated treatment duration, has revolutionized the paradigm of hepatitis C treatment and made HCV elimination possible. To provide timely guidance for optimal hepatitis C management, the Taiwan Association for the Study of the Liver (TASL) established an expert panel to publish a 2-part consensus statement on the management of hepatitis C in the DAA era. After comprehensive literature review and a consensus meeting, patient-oriented, genotype-guided recommendations on hepatitis C treatment for the general and special populations have been provided based on the latest indications and scientific evidence. In the first part of this consensus, we present the epidemiology and treatment situation of hepatitis C in Taiwan, the development of DAA, pre-treatment evaluation, post sustained virologic response (SVR) monitoring, and most importantly the treatment recommendations for the general population with compensated liver disease. The second part will focus on the treatment recommendations for the special populations.

Generation Gap for Screening and Treatment of Hepatitis C Virus in Saga Prefecture, Japan: An Administrative Database Study of 35,625 Subjects

Objective Despite recent advances in hepatitis C virus (HCV) treatment, some HCV-positive individuals are unaware of their infection. The present study aimed to assess the rate and age distribution in Saga Prefecture regarding i) HCV infection and HCV screening and ii) direct acting anti-viral (DAA) treatment. Methods HCV screening data collected at a medical institution or in the workplace were obtained from the administrative database in Saga Prefecture between April 1, 2008 and March 31, 2014. DAA treatment data from Saga Prefecture were obtained from the DAA treatment reimbursement recipient database between October 2014 and March 2017. Results There were 35,625 individuals who underwent HCV screening, and the HCV positive rate was 1.18% (421 individuals), which increased in an age-related manner. The screening rate in the screened populations peaked at 45-74 years of age (approximately 6%) and decreased in the younger and older generations. The estimated percentage of DAA treatment peaked at 65-74 years old (65.8%) and significantly decreased inversely with age in the younger generations; only 9.4% of HCV carriers received DAA treatment in the 20- to 34-year age group. The proportion of subjects who received a complete physical examination for DAA treatment was higher in the subjects who were screened at a medical institution than in those screened at the workplace. Conclusion The rate of subjects who underwent HCV screening and DAA treatment was not high, especially in the younger generation, in Saga Prefecture. This group should be targeted for HCV screening and treatment.

The outcome of combined treatment with ombitasvir-paritaprevir-ritonavir, sofosbuvir with or without ribavirin as salvage therapy for Egyptian HCV experienced patients: A single center study

We aimed to investigate the efficacy and safety of combination of sofosbuvir with ombitasvir, paritaprevir, and ritonavir ± ribavirin as a retreatment option for experienced Egyptian patients who failed previous sofosbuvir, daclatasvir ± ribavirin therapy. A total of 75 treatment-experienced patients were allocated for the completion of their treatment period according to criteria formed by the national committee for control of viral hepatitis. The enrolled patients were followed up throughout treatment, at the end of treatment and 3 months after the end of the treatment by clinical evaluation and laboratory investigations. 27 patients were treated with sofosbuvir with ombitasvir, paritaprevir, and ritonavir plus ribavirin for 12 weeks while 48 patients were treated with sofosbuvir with ombitasvir, paritaprevir, and ritonavir without ribavirin for 24 weeks. The per-protocol sustained virological response at week 12 (SVR12) rate was 100% in both groups while the intention-to-treat SVR12 was 93.4% in all patients, 97.9% in the 24 weeks group and 85.2% in the 12 weeks group. The regimen was well tolerated and the most common adverse effects observed across treatment and during follow-up period included fatigue (38.6%) and headache (29.3%), withdrawal due to adverse effects occurred in 6.6%. We can conclude that retreatment with sofosbuvir with ombitasvir, paritaprevir, and ritonavir ± ribavirin is well tolerated and achieved high SVR12 rates in chronic HCV Egyptian patients with previous sofosbuvir plus daclatasvir treatment failure. Ribavirin free regimen for 24 weeks exerted significant lesser adverse effects.

Antioxidants benefits in hepatitis C infection in the new DAAs era

Some of the evidence on whether antioxidant supplements are effective in treatment of liver diseases is contradictory. Here we perform a descriptive analysis of the available data in vivo and in vitro of the possible antiviral action and controversy of several antioxidant molecules against HCV.

Modulation of calcium signaling pathway by hepatitis C virus core protein stimulates NLRP3 inflammasome activation

Hepatitis C virus (HCV) infection remains a major cause of hepatic inflammation and liver disease. HCV triggers NLRP3 inflammasome activation and interleukin-1β (IL-1β) production from hepatic macrophages, or Kupffer cells, to drive the hepatic inflammatory response. Here we examined HCV activation of the NLRP3 inflammasome signaling cascade in primary human monocyte derived macrophages and THP-1 cell models of hepatic macrophages to define the HCV-specific agonist and cellular processes of inflammasome activation. We identified the HCV core protein as a virion-specific factor of inflammasome activation. The core protein was both necessary and sufficient for IL-1β production from macrophages exposed to HCV or soluble core protein alone. NLRP3 inflammasome activation by the HCV core protein required calcium mobilization linked with phospholipase-C activation. Our findings reveal a molecular basis of hepatic inflammasome activation and IL-1β release triggered by HCV core protein.

This study deciphers the molecular mechanism of Hepatitis C virus (HCV)-induced hepatic inflammation. HCV triggers NLRP3 inflammasome activation and IL-1β release from hepatic macrophages, thus driving liver inflammation. Using biochemical, virological, and genetic approaches we identified the HCV core protein as the specific viral stimulus that triggers intracellular calcium signaling linked with phospholipase-C activation to drive NLRP3 inflammasome activation and IL-1β release in macrophages.

Hepatitis C virus: Enslavement of host factors

Hepatitis C virus (HCV) has infected over 170 million people world-wide. This infection causes severe liver damage that can progress to hepatocellular carcinoma leading to death of the infected patients. Development of a cell culture model system for the study of HCV infection in the recent past has helped the researchers world-wide to understand the biology of this virus. Studies over the past decade have revealed the tricks played by the virus to sustain itself, for as long as 40 years, in the host setup without being eliminated by the immune system. Today we understand that the host organelles and different cellular proteins are affected during HCV infection. This cytoplasmic virus has all the cellular organelles at its disposal to successfully replicate, from ribosomes and intracellular membranous structures to the nucleus. It modulates these organelles at both the structural and the functional levels. The vast knowledge about the viral genome and viral proteins has also helped in the development of drugs against the virus. Despite the achieved success rate to cure the infected patients, we struggle to eliminate the cases of recurrence and the non-responders. Such cases might emerge owing to the property of the viral genome to accumulate mutations during its succeeding replication cycles which favours its survival. The current situation calls an urgent need for alternate therapeutic strategies to counter this major problem of human health. © 2017 IUBMB Life, 70(1):41-49, 2018.

Cost-Effectiveness Analysis of Early Treatment of Chronic HCV with Sofosbuvir/Velpatasvir in Italy

BACKGROUND

Chronic Hepatitis C virus (cHCV) is a major health issue worldwide. New effective direct-acting anti-viral (DAA) drugs such as the combination sofosbuvir/velpatasvir, represent an important turning point, given the high sustained virologic response (SVR) rates associated with their use.

OBJECTIVES

To estimate the cost and effects of two different treatment strategies based on sofosbuvir/velpatasvir. Strategy 1: treating all patients, including those in the early stages of fibrosis; Strategy 2: reserving treatments for patients at more advanced stages of disease (≥ F3). The analysis compares the incremental cost-effectiveness ratio (ICER) of Strategy 1 versus Strategy 2 in a cohort of HCV-infected patients and a cohort of hepatitis C virus (HCV)-human immunodeficiency virus (HIV) patients.

METHODS

A Markov model simulating the natural history of the disease was built considering a 60-year time horizon and two cohorts of 1000 patients aged ≥ 35 years. Disease morbidity was classified according to the METAVIR classification. The robustness of the model was tested using deterministic and probabilistic sensitivity analyses (PSA).

RESULTS

In both cohorts, Strategy 1 results in higher resource consumption and a greater number of quality-adjusted life-years (QALYs) compared with Strategy 2. The ICERs for the cohort of HCV patients and the cohort of co-infected HCV/HIV patients ranged between €15,555-74,804/QALY and €10,708-55,138/QALY, respectively, depending on the assumed cost of the treatment. In the PSA, the ICER distribution remained below the threshold of €30,000/QALY in 96 and 97% of the scenarios in the cohorts of HCV and HCV/HIV patients, respectively.

CONCLUSIONS

Extending the treatment of HCV to patients at an early stage of HCV infection is estimated to be cost effective from the perspective of the Italian Healthcare System.

Sulfur(vi) fluoride exchange as a key reaction for synthesizing biaryl sulfate core derivatives as potent hepatitis C virus NS5A inhibitors and their structure-activity relationship studies

Extremely potent, new hepatitis C virus (HCV) nonstructural 5A (NS5A) featuring substituted biaryl sulfate core structures was designed and synthesized. Based on the previously reported novel HCV NS5A inhibitors featuring biaryl sulfate core structures which exhibit two-digit picomolar half-maximal effective concentration (EC50) values against HCV genotype 1b and 2a, the new inhibitors equipped with the sulfate core structures containing diversely substituted aryl groups were explored. In this study, highly efficient, chemoselective coupling reactions between an arylsulfonyl fluoride and an aryl silyl ether, known as the sulfur(vi) fluoride exchange (SuFEx) reaction, were utilized. Among the inhibitors prepared based on the SuFEx chemistry, compounds 14, 15 and 29 exhibited two-digit picomolar EC50 values against GT-1b and single digit or sub nanomolar activities against the HCV GT-2a strain. Nonsymmetrical inhibitors containing an imidazole and amide moieties on each side of the sulfate core structures were also synthesized. In addition, a biotinylated probe targeting NS5A protein was prepared for labeling using the same synthetic methodology.

Retreatment Efficacy of Sofosbuvir/Ombitasvir/Paritaprevir/Ritonavir + Ribavirin for Hepatitis C Virus Genotype 4 Patients

BACKGROUND

The current standard of care for patients with chronic hepatitis C virus (HCV) infection is a combination of direct-acting antiviral agents (DAAs). However, rare clinical trials have been reported on the combination regimen of sofosbuvir (SOF) with ombitasvir, paritaprevir, and ritonavir (OBV/PTV/r) plus ribavirin (RBV) for treated patients with HCV genotype 4 (GT4) infection.

AIMS

To clarify the retreatment efficacy and safety of the recent regimen, SOF with OBV/PTV/r + RBV, for chronic HCV GT4-experienced patients who failed treatment with DAA-based regimens.

METHODS

A total of 113 treatment-experienced patients were allocated for the completion of their treatment period. The enrolled patients were treated orally with SOF plus a fixed dose combination of OBV/PTV/r + RBV, which was administered orally based on the patients' tolerability. The primary end point was a sustained virological response (HCV RNA < 15 IU/mL), observed 12 weeks after the end of the treatment (SVR12).

RESULTS

Among all patients, the treatment-experienced patients with SOF plus OBV/PTV/r + RBV had a higher SVR12 rate (97%; 109/113). Further, SVR12 was achieved by 98% (81/83) of non-cirrhotic patients and 93% (28/30) of cirrhotic patients. Additionally, the most common adverse events reported included fatigue, headache, insomnia, nausea, and dyspnea.

CONCLUSIONS

The recent multi-targeted regimen of SOF plus OBV/PTV/r + RBV was well tolerated and achieved excellent SVR rates among retreatment-experienced Egyptian patients with prior DAA treatments failure, thus providing an alternative regimen for the retreatment of difficult-to-cure HCV GT4 patients.

Changes in serum lipid profiles caused by three regimens of interferon-free direct-acting antivirals for patients infected with hepatitis C virus

AIM

Serum low-density lipoprotein cholesterol (LDL-C) increases during treatment of chronic hepatitis C (CHC) with interferon-free direct-acting antivirals (DAAs). We sought to compare the changes of serum lipid profiles caused by three regimens.

METHODS

A total of 216 CHC patients were enrolled. Among 170 patients infected with hepatitis C virus (HCV) genotype 1b, 85 received daclatasvir plus asunaprevir (DCV/ASV) and 85 received sofosbuvir plus ledipasvir (SOF/LDV). Forty-six infected with HCV genotype 2 received sofosbuvir plus ribavirin (SOF/RBV). Serum total cholesterol (TC), LDL-C, high-density lipoprotein cholesterol, and triglyceride were measured at baseline and 4, 8, 12 (for all regimens), and 24 weeks (for DCV/ASV) during treatment (4w, 8w, 12w, and 24w, respectively) and 12 and 24 weeks after treatment (p12w and p24w, respectively).

RESULTS

In 69 (81.2%) patients who received DCV/ASV and achieved a sustained virologic response at 24 weeks after the end of treatment (SVR24), TC and LDL-C increased significantly from baseline to p24w. In 84 (98.8%) treated with SOF/LDV who achieved SVR24, TC and LDL-C increased significantly from baseline to 8w, and TC decreased significantly from 8w to p12w. The 45 (97.8%) who received SOF/RBV and achieved SVR24 showed no significant changes. At 12w, TC and LDL-C increased to a greater degree in patients receiving SOF/LDV than in those receiving DCV/ASV or SOF/RBV.

CONCLUSION

During treatment with DAAs, the serum lipid profile may reflect not only recovery from the disruption of lipid metabolism induced by HCV, but also the pharmacological effects of DAAs. Further investigations are needed to elucidate the effect of DAAs on serum lipid profiles.

Global elimination of hepatitis C virus infection: Progresses and the remaining challenges

Today, with the introduction of interferon-free direct-acting antivirals and outstanding progresses in the prevention, diagnosis and treatment of hepatitis C virus (HCV) infection, the elimination of HCV infection seems more achievable. A further challenge is continued transmission of HCV infection in high-risk population specially injecting drug users (IDUs) as the major reservoir of HCV infection. Considering the fact that most of these infections remain undiagnosed, unidentified HCV-infected IDUs are potential sources for the rapid spread of HCV in the community. The continuous increase in the number of IDUs along with the rising prevalence of HCV infection among young IDUs is harbinger of a forthcoming public health dilemma, presenting a serious challenge to control transmission of HCV infection. Even the changes in HCV genotype distribution attributed to injecting drug use confirm this issue. These circumstances create a strong demand for timely diagnosis and proper treatment of HCV-infected patients through risk-based screening to mitigate the risk of HCV transmission in the IDUs community and, consequently, in the society. Meanwhile, raising general awareness of HCV infection, diagnosis and treatment through public education should be the core activity of any harm reduction intervention, as the root cause of failure in control of HCV infection has been lack of awareness among young drug takers. In addition, effective prevention, comprehensive screening programs with a specific focus on high-risk population, accessibility to the new anti-HCV treatment regimens and public education should be considered as the top priorities of any health policy decision to eliminate HCV infection.

A Simple but Accurate Method for Evaluating Drug-Resistance in Infectious HCVcc System

Use of direct-acting antivirals sometimes causes viral drug resistance, resulting in inefficiency in treated patients in real-world practice. Therefore, how to rapidly and accurately evaluate drug resistance is an urgent problem to be solved for rational use and development of antivirals in the future. Here, we aim to develop a new method by which we can evaluate easily but effectively whether a drug will still be efficient in the future treatment in infectious hepatitis C virus cell culture system. HCV-infected Huh7.5 cells were treated with drugs and the culture supernatants were replaced with fresh culture media containing the same drugs at 24 hours. The supernatants were harvested at 48 hours and incubated with naïve Huh7.5 cells. Intracellular HCV RNAs or proteins in the newly infected cells were extracted and analyzed at 48 hours or longer. Results showed that after being treated with telaprevir mutant viruses were easily detected which were resistant to telaprevir, while after being treated with sofosbuvir drug-resistant viruses did not emerge. In conclusion, the new method is simple and quick but accurate to evaluate whether a drug will be still efficient in the forthcoming therapeutic regimen and whether drug resistance will occur after long-term treatment with drugs.

Direct-acting antivirals for hepatitis C virus in patients on maintenance dialysis

The frequency of hepatitis C virus (HCV) infection remains high in patients with chronic kidney disease (CKD) and plays a detrimental role in mortality in this population. According to the latest survey, the adjusted hazard ratio for HCV-positive versus HCV-negative patients on long-term dialysis was 1.12 (95% CI, 1.05 to 1.20) and 1.10 (95% CI, 0.98 to 1.22) for all-cause and cardiovascular mortality, respectively. An impairment on quality of life has also been documented in HCV-infected patients undergoing regular dialysis. Most clinicians have been so far reluctant to treat hepatitis C in patients with advanced CKD, due to concerns regarding low efficacy and safety of interferon-based regimens. The advent of all-oral, direct-acting antivirals (DAAs) has revolutionized treatment paradigms for HCV, including patients with other comorbidities such as CKD. Two combinations of DAAs have been recently approved for the treatment of HCV in advanced CKD: elbasvir/grazoprevir (evaluated in 1 randomized controlled trial) and ombitasvir/paritaprevir/ritonavir/dasabuvir with or without ribavirin (examined in some observational, single-arm studies). These antiviral combinations have provided high safety and efficacy (SVR12 rates >90%) in HCV-infected patients with stage 4-5 CKD. Sofosbuvir, a nucleotide analogue inhibitor of the HCV NS5B polymerase, is the cornerstone of most anti-HCV current regimens but is not currently recommended for patients with severe renal insufficiency (eGFR <30 mL/min per 1.73 m2). However, several small-sized studies have been published on the safety and efficacy of sofosbuvir-based regimens for patients with hepatitis C on maintenance dialysis; overall, the viral response was satisfactory (SVR12 rates ranging between 58% and 100%) with a few drug-related drop-outs. Studies are in progress to assess whether ribavirin-free antiviral combinations with novel DAAs are a viable option for patients with severe renal impairment and chronic HCV infection.

Prevalence of IFNL3 rs4803217 single nucleotide polymorphism and clinical course of chronic hepatitis C

AIM

To evaluate the association of IFNL3 (IL28B) SNP rs4803217 with severity of disease and treatment outcome in chronic hepatitis C (CHC).

METHODS

The study enrolled 196 CHC Polish patients (82 women and 114 men in age 20-64) infected with hepatitis C virus (HCV) genotype 1. They were treatment naïve and qualified to pegylated interferon alpha (PEG-IFN-α) and ribavirin (RBV) therapy. The analyzed baseline parameters included: degree of inflammation, stage of fibrosis, viral load as well as alanine aminotransferase (ALT), asparagine aminotransferase (AST) and total bilirubin (TBIL). The analysis of response to therapy included: sustained virological response (SVR), defined as undetectable serum HCV RNA level six month after completion of 48-wk therapy, and relapse, defined as achieving undetectable viral load at the end of treatment but not SVR. HCV genotyping and HCV RNA quantification were performed using commercially available tests. DNA was isolated from peripheral blood mononuclear cells or from buccal cell swabs. In addition to rs4803217, also single nucleotide polymorphisms (SNPs) (rs12979860, rs8099917 and rs12980275) of known significance in predicting of HCV clearance were analyzed. SNPs were determined by high resolution melt analysis and confirmed by sequencing of amplicons.

RESULTS

Frequency of rs4803217 genotypes in studied group was as follows: 27.55%; 54.59% and 17.86% for CC, CA and AA, respectively. The rs4803217 SNP, similar to other analyzed SNPs, was not associated with severity of CHC (grade of inflammation, stage of fibrosis, baseline viral load as well as biochemical parameters: ALT, AST, TBIL). It was demonstrated that the rs4803217C allele is associated with SVR (C vs A: P < 0.0001; dose of C allele: P = 0.0002) and non-relapse (C vs A: P = 0.001; dose of C allele: P = 0.002). Moreover, it was found that patients with CC genotype have significantly higher response rates as compared with CA/AA patients (P < 0.0001), whereas patients carrying A allele are significantly predisposed to relapse after treatment (P = 0.0007). Moreover, the association of rs4803217 with SVR was comparable to that of rs12979860 and stronger as observed for rs12980275 and rs8099917. Association of rs4803217 with relapse, was the strongest as compared with the other SNPs. The analysis of combined rs4803217 and rs8099917 genotypes demonstrated that additional genotyping of rs8099917 had no significant impact on the prediction of SVR. Multivariate analysis revealed that among analyzed SNPs only rs4803217 is an independent predictor of SVR (P = 0.016) and relapse (P = 0.024).

CONCLUSION

The rs4803217 SNP is a strong, independent and superior predictor of SVR and relapse in HCV genotype 1 infected CHC patients treated with PEG-IFN-α and RBV.

Risk Assessment of Hepatocellular Carcinoma in General Population by Liver Stiffness in Combination with Controlled Attenuation Parameter using Transient Elastography: A Cross Sectional Study

BACKGROUND

Hepatocellular carcinoma (HCC) in patients without hepatitis B (HBV) and -C virus (HCV) infection are increasing in Japan. Method for detecting high-risk liver diseases of HCC in general population has still not been established. Liver stiffness measurement (LSM) and Controlled Attenuation Parameter (CAP) using transient elastography (TE; FibroScan System) are useful for detecting liver fibrosis and steatosis. The aim of this study is to clarify TE for risk assessment of HCC in general population.

METHODS

This cross-sectional study was performed for residents aged ≥ 40 years in an intermountain town in Japan with a population of 3,493. Blood laboratory testing included tumor markers, abdominal ultrasound (AUS), and TE was performed.

RESULTS

Among 175 subjects (64 men, 111 women), TE was evaluated and three patients with HCC were detected by AUS. For detecting HCC, the cut-off value of LSM was 5.3 kPa sensitivity 100%, specificity 75%, AUROC 0.88). The combination of LSM and CAP (LSM > 5.3 kPa with any CAP and CAP > 248 dB/m with any LSM) could detect the high-risk liver diseases of HCC (HCC, nonalcoholic fatty liver/steatohepatitis, HBV or HCV related chronic viral hepatitis with alanine transaminase (ALT) > 30 IU/L for men or > 19 IU/L for women or cirrhosis of any cause) with high sensitivity (sensitivity 90%, specificity 55%, positive predictive value 10%, negative predictive value 99%, P = 0.006).

CONCLUSION

The combination of LSM and CAP can be useful in detecting high-risk liver diseases of HCC out of general population.

Hepatitis B virus infection and alcohol consumption

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, and the second most common cause of cancer deaths worldwide. The top three causes of HCC are hepatitis B virus (HBV), hepatitis C virus (HCV), and alcoholic liver disease. Owing to recent advances in direct-acting antiviral agents, HCV can now be eradicated in almost all patients. HBV infection and alcoholic liver disease are expected, therefore, to become the leading causes of HCC in the future. However, the association between alcohol consumption and chronic hepatitis B in the progression of liver disease is less well understood than with chronic hepatitis C. The mechanisms underlying the complex interaction between HBV and alcohol are not fully understood, and enhanced viral replication, increased oxidative stress and a weakened immune response could each play an important role in the development of HCC. It remains controversial whether HBV and alcohol synergistically increase the incidence of HCC. Herein, we review the currently available literature regarding the interaction of HBV infection and alcohol consumption on disease progression.

Recent advances in hepatocellular carcinoma therapy

Hepatocellular carcinoma (HCC), also called malignant hepatoma, is one of the deadliest cancers due to its complexities, reoccurrence after surgical resection, metastasis and heterogeneity. Incidence and mortality of HCC are increasing in Western countries and are expected to rise as a consequence of the obesity epidemic. Multiple factors trigger the initiation and progression of HCC including chronic alcohol consumption, viral hepatitis B and C infection, metabolic disorders and age. Although Sorafenib is the only FDA approved drug for the treatment of HCC, numerous treatment modalities such as transcatheter arterial chemoembolization/transarterial chemoembolization (TACE), radiotherapy, locoregional therapy and chemotherapy have been tested in the clinics. Polymeric nanoparticles, liposomes, and micelles carrying small molecules, proteins, peptides and nucleic acids have attracted great attention for the treatment of various cancers including HCC. Herein, we discuss the pathogenesis of HCC in relation to its various recent treatment methodologies using nanodelivery of monoclonal antibodies (mAbs), small molecules, miRNAs and peptides. Synopsis of recent clinical trials of mAbs and peptide drugs has been presented with a broad overview of the pathogenesis of the disease and treatment efficacy.

Small-molecule inhibitors of hepatitis C virus (HCV) non-structural protein 5A (NS5A): a patent review (2010-2015)

INTRODUCTION

Non-structural 5A (NS5A) protein has achieved a considerable attention as an attractive target for the treatment of hepatitis C (HCV). A number of novel NS5A inhibitors have been reported to date. Several drugs having favorable ADME properties and mild side effects were launched into the pharmaceutical market. For instance, daclatasvir was launched in 2014, elbasvir is currently undergoing registration, ledipasvir was launched in 2014 as a fixed-dose combination with sofosbuvir (NS5B inhibitor). Areas covered: Thomson integrity database and SciFinder database were used as a valuable source to collect the patents on small-molecule NS5A inhibitors. All the structures were ranked by the date of priority. Patent holder and antiviral activity for each scaffold claimed were summarized and presented in a convenient manner. A particular focus was placed on the best-in-class bis-pyrrolidine-containing NS5A inhibitors. Expert opinion: Several first generation NS5A inhibitors have recently progressed into advanced clinical trials and showed superior efficacy in reducing viral load in infected subjects. Therapy schemes of using these agents in combination with other established antiviral drugs with complementary mechanisms of action can address the emergence of resistance and poor therapeutic outcome frequently attributed to antiviral drugs.

Prognostic significance of nonprotein respiratory quotient in patients with liver cirrhosis

The aim of this study was to examine the effect of nonprotein respiratory quotient (npRQ), as assessed using indirect calorimetry, on clinical outcomes in patients with liver cirrhosis (LC). A total of 244 LC patients were evaluated in this study. For the univariate analysis, for each continuous variable, the optimal cutoff value that maximized the sum of sensitivity and specificity was selected using receiver operating curve (ROC) analysis for survival. There were 137 men and 107 women with the median (range) age of 67 (25-90) years. Indirect calorimetry indicated that 54 patients (22.1%) had hepatocellular carcinoma (HCC) on radiological findings and 59 patients (24.2%) had protein energy malnutrition, as defined by npRQ <0.85 and serum albumin level <3.5 g/dL. In ROC analysis of npRQ for survival, the optimal cutoff point of npRQ was 0.849 for all cases (area under the ROC = 0.61272; sensitivity, 66.22%; and specificity, 57.06%). The median follow-up periods after indirect calorimetry were 4.35 years (range, 1.01-9.66 years) in patients with npRQ ≥0.85 (n = 122) and 3.71 years (range, 0.19-9.51 years) in patients with npRQ <0.85 (n = 122). The 1-, 3-, and 5-year cumulative OS rates in patients with npRQ ≥0.85 were 100%, 87.79%, and 77.24%, respectively, whereas those in patients with npRQ <0.85 were 94.26%, 73.65% and 57.78%, respectively (P = 0.0004). In the multivariate analysis, presence of HCC (P = 0.0045), body mass index (P < 0.0001), serum albumin (P = 0.0441), prothrombin time (P = 0.0463), npRQ (P = 0.0024), estimated glomerular filtration rate (P = 0.0086), and des-γ-carboxy prothrombin (P = 0.0268) were found to be significant predictors associated with OS. For all cases, risk stratification for survival was well performed using these significant variables. In conclusion, npRQ value, as assessed by indirect calorimetry, can be helpful for predicting clinical outcomes for LC patients.

Use of Aptamers as Diagnostics Tools and Antiviral Agents for Human Viruses

Appropriate diagnosis is the key factor for treatment of viral diseases. Time is the most important factor in rapidly developing and epidemiologically dangerous diseases, such as influenza, Ebola and SARS. Chronic viral diseases such as HIV-1 or HCV are asymptomatic or oligosymptomatic and the therapeutic success mainly depends on early detection of the infective agent. Over the last years, aptamer technology has been used in a wide range of diagnostic and therapeutic applications and, concretely, several strategies are currently being explored using aptamers against virus proteins. From a diagnostics point of view, aptamers are being designed as a bio-recognition element in diagnostic systems to detect viral proteins either in the blood (serum or plasma) or into infected cells. Another potential use of aptamers is for therapeutics of viral infections, interfering in the interaction between the virus and the host using aptamers targeting host-cell matrix receptors, or attacking the virus intracellularly, targeting proteins implicated in the viral replication cycle. In this paper, we review how aptamers working against viral proteins are discovered, with a focus on recent advances that improve the aptamers' properties as a real tool for viral infection detection and treatment.

The NS4A Cofactor Dependent Enhancement of HCV NS3 Protease Activity Correlates with a 4D Geometrical Measure of the Catalytic Triad Region

We are developing a 4D computational methodology, based on 3D structure modeling and molecular dynamics simulation, to analyze the active site of HCV NS3 proteases, in relation to their catalytic activity. In our previous work, the 4D analyses of the interactions between the catalytic triad residues (His57, Asp81, and Ser139) yielded divergent, gradual and genotype-dependent, 4D conformational instability measures, which strongly correlate with the known disparate catalytic activities among genotypes. Here, the correlation of our 4D geometrical measure is extended to intra-genotypic alterations in NS3 protease activity, due to sequence variations in the NS4A activating cofactor. The correlation between the 4D measure and the enzymatic activity is qualitatively evident, which further validates our methodology, leading to the development of an accurate quantitative metric to predict protease activity in silico. The results suggest plausible “communication” pathways for conformational propagation from the activation subunit (the NS4A cofactor binding site) to the catalytic subunit (the catalytic triad). The results also strongly suggest that the well-sampled (via convergence quantification) structural dynamics are more connected to the divergent catalytic activity observed in HCV NS3 proteases than to rigid structures. The method could also be applicable to predict patients’ responses to interferon therapy and better understand the innate interferon activation pathway.

Interleukin 10 gene single nucleotide polymorphisms in Polish patients with chronic hepatitis C: Analysis of association with severity of disease and treatment outcome

It is suggested that interleukin 10 (IL-10), as a modulator of immune response, is likely to influence the elimination of hepatitis C virus (HCV), the progression of chronic hepatitis C (CHC) and the response to interferon-based therapy in CHC patients. The aim of the study was to analyze the association of single nucleotide polymorphisms (SNPs) of IL-10 gene with severity of liver disease (degree of inflammation and stage of fibrosis) and outcome of pegylated interferon alpha and ribavirin combined therapy (sustained virological response (SVR) and relapse) in 196 Polish CHC patients infected with HCV genotype 1. The analysis included IL-10 promoter SNPs: -1082(A/G) rs1800896, -819(C/T) rs1800871, -592(C/A) rs1800872 and SNP in the 3' UTR of IL-10 gene: +4529(A/G) rs3024498. Genotyping was performed using PCR-RFLP and HRM analysis. It was demonstrated that the -592C allele is associated with mild hepatic inflammation. Moreover, it was found that the -819C allele might be associated with SVR and that the ACCA haplotype and intermediate IL-10 producer ACC haplotype are associated with SVR and non-relapse. It can be concluded that IL-10 SNPs are associated with severity of disease and response to therapy and may be considered as potential prognostic and predictive markers in CHC.

Isolation and characterization of hepatitis C virus resistant to a novel phenanthridinone derivative

BACKGROUND

The novel phenanthridinone derivative HA-719 has recently been identified as a highly potent and selective inhibitor of hepatitis C virus replication. To elucidate its mechanism of inhibition, we have isolated and analyzed a clone of hepatitis C virus replicon cells resistant to HA-719.

METHODS

To isolate HA-719-resistant replicon cells, Huh-7 cells containing subgenomic hepatitis C virus replicons (genotype 1b) with a luciferase reporter (LucNeo#2) were cultured in the presence of G418 and escalating concentrations of HA-719. After several passages, total RNA was extracted from the growing cells, and Huh-7 cells were transfected with the extracted RNA. Limiting dilution of the transfected cells was performed to obtain an HA-719-resistant clone.

RESULTS

The 50% effective concentration (EC₅₀) of HA-719 for hepatitis C virus replication was 0.058 ± 0.012 µM in LucNeo#2 cells. The replicon cells capable of growing in the presence of G418 and 3 µM HA-719 were obtained after 18 passages (72 days). The HA-719-resistant clone LucNeo719R showed 98.3-fold resistant to the compound (EC₅₀ = 5.66 ± 0.92 µM), but the clone had no cross-resistance to telaprevir (NS3 inhibitor), daclatasvir (NS5A inhibitor), and VX-222 (NS5B inhibitor). The sequence analysis for the wild-type and LucNeo719R identified 3, 2 and 7 mutations in NS3/4 A, NS4B, and NS5A, respectively, but no mutations in NS5B.

CONCLUSION

None of the amino acid mutations in the resistant clone corresponds to those reported to confer drug-resistance to current anti-hepatitis C virus agents, suggesting that the target of HA-719 for hepatitis C virus inhibition differs from those of the existing agents.

Promising Anti-Hepatitis C Virus Compounds from Natural Resources

Hepatitis C virus (HCV) infection is a major worldwide problem, which involves approximately 170 million people. High morbidity of patients is caused by chronic infection, which leads to liver cirrhosis, hepatocellular carcinoma and other HCV-related diseases. The sustained virological response (SVR) has been markedly improved to be >90% by the current standard interferon (IFN)-free treatment regimens with a combination of direct-acting antiviral agents (DAAs) targeting the viral NS3 protease, NS5A multi-function protein and NS5B RNA-dependent RNA polymerase, compared with 50–70% of SVR rates achieved by the previous standard IFN-based treatment regimens with or without an NS3 protease inhibitor. However, the emergence of DAA-resistant HCV strains and the limited access to the DAAs due to their high cost could be major concerns. Also, the long-term prognosis of patients treated with DAAs, such as the possible development of hepatocellular carcinoma, still needs to be further evaluated. Natural resources are considered to be good candidates to develop anti-HCV agents. Here, we summarize anti-HCV compounds obtained from natural resources, including medicinal plant extracts, their isolated compounds and some of their derivatives that possess high antiviral potency against HCV.

Hepatitis C virus: Promising discoveries and new treatments

Despite advances in therapy, hepatitis C virus (HCV) infection remains an important global health issue. It is estimated that a significant part of the world population is chronically infected with the virus, and many of those affected may develop cirrhosis or liver cancer. The virus shows considerable variability, a characteristic that directly interferes with disease treatment. The response to treatment varies according to HCV genotype and subtype. The continuous generation of variants (quasispecies) allows the virus to escape control by antivirals. Historically, the combination of ribavirin and interferon therapy has represented the only treatment option for the disease. Currently, several new treatment options are emerging and are available to a large part of the affected population. In addition, the search for new substances with antiviral activity against HCV continues, promising future improvements in treatment. Researchers should consider the mutation capacity of the virus and the other variables that affect treatment success.