Status of Direct-Acting Antiviral Therapy for Hepatitis C Virus Infection and Remaining Challenges

A therapeutic approach for the hepatitis C virus: in silico design of an antisense oligonucleotide-based candidate capsid inhibitor

Direct-acting antiviral (DAA) drugs have been shown to effectively reduce viral load and cure a high proportion of hepatitis C virus (HCV) infections. However, costs associated with the course of therapy and any possible adverse effects should also be considered. It is important to acknowledge, moreover, that certain groups may not be eligible for treatment. Given that there is currently no approved vaccine for HCV infection, the need for an effective, safe, and accessible treatment remains a crucial priority. The aim of this study is to develop an antisense oligonucleotide (ASO)-based therapeutic drug that can inhibit HCV capsid. After analyzing 817 HCV capsid protein mRNA sequences using the NCBI Virus Data Portal, a conserved region of 7 nucleotides (nt) was identified in all genotypes (1-7). However, because of its high GC% content, this region is not a suitable target for ASO. Conversely, the other highly conserved region, which is only 8 nt long, was preserved in 801 datasets after removing missing and differing sequence data. The candidate ASO was then investigated using computer simulations to assess its potential. Thus, it is possible that the ASO sequence consisting of 8 nt could be a viable therapeutic target for the inhibition of HCV capsid. Furthermore, the 7 nt sequence, which is conserved in all datasets, may be targeted using alternative strategies in lieu of ASO-based targeting.

The Efficacy of Glecaprevir/Pibrentasvir in Chronic Hepatitis C Patients and the Impact of the COVID-19 Pandemic: Multicenter Real-Life Data

Objective

This study aimed to demonstrate the real-life efficacy and safety of glecaprevir /pibrentasvir in the treatment of chronic hepatitis C, as well as to identify the problems caused by the COVID-19 pandemic in the follow-up and treatment of patients.

Materials and Methods

The study was conducted retrospectively with the participation of researchers from universities or training and research hospitals. It included patients with chronic hepatitis C who were over 18 years of age, treatment-naïve or treatment-experienced, had detectable HCV RNA and were receiving glecaprevir/pibrentasvir treatment.

Results

Only 188 of the 385 patients who participated in the study came to the follow-up visit 12 weeks after treatment, and all of them had a sustained virological response. It was thought that a significant portion of the 177 patients who did not come to the follow-up visit at 12 weeks after treatment refrained from coming to the hospital due to the COVID-19 pandemic. None of the patients who attended the follow-up visits required treatment discontinuation due to adverse events.

Conclusion

Glecaprevir/pibrentasvir is a highly effective and relatively safe drug in the treatment of chronic hepatitis C. The COVID-19 pandemic has negatively affected the follow-up and treatment processes of patients. New measures are needed for the follow-up and treatment of patients with chronic hepatitis C during pandemics.

Hijacking autophagy for infection by flaviviruses

Autophagy is a lysosomal degradative pathway, which regulates the homeostasis of eukaryotic cells. This pathway can degrade misfolded or aggregated proteins, clear damaged organelles, and eliminate intracellular pathogens, including viruses, bacteria, and parasites. But, not all types of viruses are eliminated by autophagy. Flaviviruses (e.g., Yellow fever, Japanese encephalitis, Hepatitis C, Dengue, Zika, and West Nile viruses) are single-stranded and enveloped RNA viruses, and transmitted to humans primarily through the bites of arthropods, leading to severe and widespread illnesses. Like the coronavirus SARS-CoV-II, flaviviruses hijack autophagy for their infection and escape from host immune clearance. Thus, it is possible to control these viral infections by inhibiting autophagy. In this review, we summarize recent research progresses on hijacking of autophagy by flaviviruses and discuss the feasibility of antiviral therapies using autophagy inhibitors.

An atlas of the human liver diurnal transcriptome and its perturbation by hepatitis C virus infection

Chronic liver disease and cancer are global health challenges. The role of the circadian clock as a regulator of liver physiology and disease is well established in rodents, however, the identity and epigenetic regulation of rhythmically expressed genes in human disease is less well studied. Here we unravel the rhythmic transcriptome and epigenome of human hepatocytes using male human liver chimeric mice. We identify a large number of rhythmically expressed protein coding genes in human hepatocytes of male chimeric mice, which includes key transcription factors, chromatin modifiers, and critical enzymes. We show that hepatitis C virus (HCV) infection, a major cause of liver disease and cancer, perturbs the transcriptome by altering the rhythmicity of the expression of more than 1000 genes, and affects the epigenome, leading to an activation of critical pathways mediating metabolic alterations, fibrosis, and cancer. HCV-perturbed rhythmic pathways remain dysregulated in patients with advanced liver disease. Collectively, these data support a role for virus-induced perturbation of the hepatic rhythmic transcriptome and pathways in cancer development and may provide opportunities for cancer prevention and biomarkers to predict HCC risk.

Pharmacophore-Assisted Covalent Docking Identifies a Potential Covalent Inhibitor for Drug-Resistant Genotype 3 Variants of Hepatitis C Viral NS3/4A Serine Protease

The emergence of drug-resistance-inducing mutations in Hepatitis C virus (HCV) coupled with genotypic heterogeneity has made targeting NS3/4A serine protease difficult. In this work, we investigated the mutagenic variations in the binding pocket of Genotype 3 (G3) HCV NS3/4A and evaluated ligands for efficacious inhibition. We report mutations at 14 positions within the ligand-binding residues of HCV NS3/4A, including H57R and S139P within the catalytic triad. We then modelled each mutational variant for pharmacophore-based virtual screening (PBVS) followed by covalent docking towards identifying a potential covalent inhibitor, i.e., cpd-217. The binding stability of cpd-217 was then supported by molecular dynamic simulation followed by MM/GBSA binding free energy calculation. The free energy decomposition analysis indicated that the resistant mutants alter the HCV NS3/4A-ligand interaction, resulting in unbalanced energy distribution within the binding site, leading to drug resistance. Cpd-217 was identified as interacting with all NS3/4A G3 variants with significant covalent docking scores. In conclusion, cpd-217 emerges as a potential inhibitor of HCV NS3/4A G3 variants that warrants further in vitro and in vivo studies. This study provides a theoretical foundation for drug design and development targeting HCV G3 NS3/4A.

Contemporary Insights into Hepatitis C Virus: A Comprehensive Review

Hepatitis C virus (HCV) remains a significant global health challenge. Approximately 50 million people were living with chronic hepatitis C based on the World Health Organization as of 2024, contributing extensively to global morbidity and mortality. The advent and approval of several direct-acting antiviral (DAA) regimens significantly improved HCV treatment, offering potentially high rates of cure for chronic hepatitis C. However, the promising aim of eventual HCV eradication remains challenging. Key challenges include the variability in DAA access across different regions, slightly variable response rates to DAAs across diverse patient populations and HCV genotypes/subtypes, and the emergence of resistance-associated substitutions (RASs), potentially conferring resistance to DAAs. Therefore, periodic reassessment of current HCV knowledge is needed. An up-to-date review on HCV is also necessitated based on the observed shifts in HCV epidemiological trends, continuous development and approval of therapeutic strategies, and changes in public health policies. Thus, the current comprehensive review aimed to integrate the latest knowledge on the epidemiology, pathophysiology, diagnostic approaches, treatment options and preventive strategies for HCV, with a particular focus on the current challenges associated with RASs and ongoing efforts in vaccine development. This review sought to provide healthcare professionals, researchers, and policymakers with the necessary insights to address the HCV burden more effectively. We aimed to highlight the progress made in managing and preventing HCV infection and to highlight the persistent barriers challenging the prevention of HCV infection. The overarching goal was to align with global health objectives towards reducing the burden of chronic hepatitis, aiming for its eventual elimination as a public health threat by 2030.

JFH1-based Core-NS2 genotype variants of HCV with genetic stability in vivo and in vitro: Important tools in the evaluation of virus neutralization

BACKGROUND AND AIMS

HCV infection continues to be a major global health burden despite effective antiviral treatments. The urgent need for a protective vaccine is hindered by the scarcity of suitable HCV-permissive animal models tractable in vaccination and challenge studies. Currently, only antibody neutralization studies in infectious cell culture systems or studies of protection by passive immunization of human liver chimeric mice offer the possibility to evaluate the effect of vaccine-induced antibodies. However, differences between culture-permissive and in vivo-permissive viruses make it a challenge to compare analyses between platforms. To address this problem, we aimed at developing genotype-specific virus variants with genetic stability both in vitro and in vivo.

APPROACH AND RESULTS

We demonstrated infection of human liver chimeric mice with cell culture-adapted HCV JFH1-based Core-NS2 recombinants of genotype 1-6, with a panel of 10 virus strains used extensively in neutralization and receptor studies. Clonal re-engineering of mouse-selected mutations resulted in virus variants with robust replication both in Huh7.5 cells and human liver chimeric mice, with genetic stability. Furthermore, we showed that, overall, these virus variants have similar in vitro neutralization profiles as their parent strains and demonstrated their use for in vivo neutralization studies.

CONCLUSIONS

These mouse-selected HCV recombinants enable the triage of new vaccine-relevant antibodies in vitro and further allow characterization of protection from infection in vivo using identical viruses in human liver chimeric mice. As such, these viruses will serve as important resources in testing novel antibodies and can thus guide strategies to develop an efficient protective vaccine against HCV infection.

Molecular characterization of the nonstructural 5A (NS5A) region of hepatitis C virus in Thai blood donors

Direct acting antivirals (DAAs) have been developed for hepatitis C virus (HCV) therapy, and they are usually effective, however resistance to DAA regimens has also been reported to have a significant impact. Resistance associated substitutions (RASs) in the NS5A region are known to be correlated with failure of DAA therapy. HCV genotypes 3a and 1 are the most prevalent genotypes in Thailand. This study analyzed the type and frequency of RASs associated with DAA failure, focusing on the NS5A region. Serum samples of HCV genotype 3a, 1a, and 1b infection from Thai blood donors were selected. The NS5A region was amplified using reverse transcription-polymerase chain reaction (RT-PCR). A phylogenetic tree was constructed to identify the genotypes of HCV. Nucleotide sequencing and amino acid sequencing were conducted to determine the prevalence of RASs. Construction of the phylogenetic tree indicated that 29 samples were genotype 3a, 11 samples were genotype 1a, and 9 were genotype 1b. Both HCV genotypes 1a and 3a can be categorized into two subclades. Results showed that the NS5A substitutions A30V/K, A62T/V/I/M/P/S/L, and S98G were present in HCV genotype 3a. In HCV genotype 1a, only NS5A RASs H54Y was detected. NS5A amino acid substitutions Q54H and P58L were found in HCV genotype 1b. In conclusion, NS5A RASs at amino acid positions 30, 62, 54, 58, and 98 are present within HCV genotypes 3a and 1. While keeping in mind that additional information was not available on the anonymous blood donors tested in this study, these findings can contribute to understand the NS5A mutation. Further study with known patients under drug treatment is recommended.

Beyond schistosomiasis: unraveling co-infections and altered immunity

Schistosomiasis is a neglected tropical disease caused by the helminth Schistosoma spp. and has the second highest global impact of all parasites. Schistosoma are transmitted through contact with contaminated fresh water predominantly in Africa, Asia, the Middle East, and South America. Due to the widespread prevalence of Schistosoma, co-infection with other infectious agents is common but often poorly described. Herein, we review recent literature describing the impact of Schistosoma co-infection between species and Schistosoma co-infection with blood-borne protozoa, soil-transmitted helminths, various intestinal protozoa, Mycobacterium, Salmonella, various urinary tract infection-causing agents, and viral pathogens. In each case, disease severity and, of particular interest, the immune landscape, are altered as a consequence of co-infection. Understanding the impact of schistosomiasis co-infections will be important when considering treatment strategies and vaccine development moving forward.

Investigating the effect of polymerase inhibitors on cellular proliferation: Computational studies, cytotoxicity, CDK1 inhibitory potential, and LC-MS/MS cancer cell entrapment assays

Directly acting antivirals (DAAs) are a breakthrough in the treatment of HCV. There are controversial reports on their tendency to induce hepatocellular carcinoma (HCC) in HCV patients. Numerous reports have concluded that the HCC is attributed to patient-related factors while others are inclined to attribute this as a DAA side-effect. This study aims to investigate the effect of polymerase inhibitor DAAs, especially daclatasivir (DLT) on cellular proliferation as compared to ribavirin (RBV). The interaction of DAAs with variable cell-cycle proteins was studied in silico. The binding affinities to multiple cellular targets were investigated and the molecular dynamics were assessed. The in vitro effect of the selected candidate DLT on cancer cell proliferation was determined and the CDK1 inhibitory potential in was evaluated. Finally, the cellular entrapment of the selected candidates was assessed by an in-house developed and validated LC-MS/MS method. The results indicated that polymerase inhibitor antiviral agents, especially DLT, may exert an anti-proliferative potential against variable cancer cell lines. The results showed that the effect may be achieved via potential interaction with the multiple cellular targets, including the CDK1, resulting in halting of the cellular proliferation. DLT exhibited a remarkable cell permeability in the liver cancer cell line which permits adequate interaction with the cellular targets. In conclusion, the results reveal that the polymerase inhibitor (DLT) may have an anti-proliferative potential against liver cancer cells. These results may pose DLT as a therapeutic choice for patients suffering from HCV and are liable to HCC development.

Can Persistent Infections with Hepatitis B Virus, Hepatitis C Virus, Human Immunodeficiency Virus, and Human T Lymphotropic Virus Type 1 Be Eradicated?

Persistent viruses are hard to be eradicated, even using effective medications, and can persist for a long time in humans, sometimes regardless of treatment. Hepatitis B virus, hepatitis C virus, human immunodeficiency virus, and human T cell lymphotropic virus infections, the most common in our era, are still a challenge despite the increased knowledge about their biology. Most of them are highly pathogenic, some causing acute disease or, more often, leading to chronic persistent infections, and some of the occult, carrying a high risk of morbidity and mortality. However, if such infections were discovered early, they might be eradicated in the near future with effective medications and/or vaccines. This perspective review points out some specific characteristics of the most important chronic persistent viruses. It seems that in the next few years, these persistent viruses may have control by vaccination, epidemiological strategies, and/or treatment.

Combined "Test and Treat" Campaigns for Human Immunodeficiency Virus, Hepatitis B, and Hepatitis C: A Systematic Review to Provide Evidence to Support World Health Organization Treatment Guidelines

Background

Worldwide, more than 39 million individuals are living with human immunodeficiency virus (HIV), 296 million with chronic hepatitis B (HBV), and 58 million with chronic hepatitis C (HCV). Despite successful treatments for these blood-borne viruses (BBVs), >1.7 million people die per annum. To combat this, the World Health Organization recommended implementing triple testing for HIV, HBV, and HCV. This systematic review aims to provide evidence for this policy, by identifying the prevalence of these BBVs and discussing the costs of available triple tests.

Methods

Medline, Embase, and Global Health were searched to identify articles published between 1 January and 24 February 2023. Included studies reported the prevalence of HIV (anti-HIV 1/2 antibodies), HBV (hepatitis B surface antigen) and HCV (anti-HCV antibodies). Results were stratified into risk groups: blood donors, general population, healthcare attendees, individuals experiencing homelessness, men who have sex with men, people who use drugs, pregnant people, prisoners, and refugees and immigrants.

Results

One hundred seventy-five studies sampling >14 million individuals were included. The mean prevalence of HIV, HBV, and HCV was 0.22% (standard deviation [SD], 7.71%), 1.09% (SD, 5.80%) and 0.65% (SD, 14.64%) respectively. The mean number of individuals testing positive for at least 1 BBV was 1.90% (SD, 16.82%). Therefore, under triple testing, for every individual diagnosed with HIV, another 5 would be diagnosed with HBV and 3 with HCV. Testing for all 3 viruses is available for US$2.48, marginally more expensive than the lowest-priced isolated HIV test ($1.00).

Conclusions

This article highlights a potential avenue for healthcare improvement by implementing combination testing programs. Hopefully, this will help to achieve the Sustainable Development Goal of elimination of these BBV epidemics by 2030.

Should Human Immunodeficiency Virus Testing Be Replaced With Combined Blood-Borne Virus Testing?

Standalone HIV testing is a missed opportunity- a recent systematic review showed eight cases of viral hepatitis would be missed for each new HIV diagnosis. The review builds on a decade of research demonstrating the additional benefit of BBV testing.

Therapeutic Intervention of Serine Protease Inhibitors against Hepatitis C Virus

Hepatitis C virus (HCV) is a globally prevalent and hazardous disorder that is responsible for inducing several persistent and potentially fatal liver diseases. Current treatment strategies offer limited efficacy, often accompanied by severe and debilitating adverse effects. Consequently, there is an urgent and compelling need to develop novel therapeutic interventions that can provide maximum efficacy in combating HCV while minimizing the burden of adverse effects on patients. One promising target against HCV is the NS3-4A serine protease, a complex composed of two HCV-encoded proteins. This non-covalent heterodimer is crucial in the viral life cycle and has become a primary focus for therapeutic interventions. Although peginterferon, combined with ribavirin, is commonly employed for HCV treatment, its efficacy is hampered by significant adverse effects that can profoundly impact patients' quality of life. In recent years, the development of direct-acting antiviral agents (DAAs) has emerged as a breakthrough in HCV therapy. These agents exhibit remarkable potency against the virus and have demonstrated fewer adverse effects when combined with other DAAs. However, it is important to note that there is a potential for developing resistance to DAAs due to alterations in the amino acid position of the NS3-4A protease. This emphasizes the need for ongoing research to identify strategies that can minimize the emergence of resistance and ensure long-term effectiveness. While the combination of DAAs holds promise for HCV treatment, it is crucial to consider the possibility of drug-drug interactions. These interactions may occur when different DAAs are used concurrently, potentially compromising their therapeutic efficacy. Therefore, carefully evaluating and monitoring potential drug interactions are vital to optimize treatment outcomes. In the pursuit of novel therapeutic interventions for HCV, the field of computational biology and bioinformatics has emerged as a valuable tool. These advanced technologies and methodologies enable the development and design of new drugs and therapeutic agents that exhibit maximum efficacy, reduced risk of resistance, and minimal adverse effects. By leveraging computational approaches, researchers can efficiently screen and optimize potential candidates, accelerating the discovery and development of highly effective treatments for HCV, treatments.

Full-length sequence analysis of hepatitis C virus genotype 3b strains and development of an in vivo infectious 3b cDNA clone

IMPORTANCE

HCV genotype 3b is a difficult-to-treat subtype, associated with accelerated progression of liver disease and resistance to antivirals. Moreover, its prevalence has significantly increased among persons who inject drugs posing a serious risk of transmission in the general population. Thus, more genetic information and antiviral testing systems are required to develop novel therapeutic options for this genotype 3 subtype. We determined the complete genomic sequence and complexity of three genotype 3b isolates, which will be beneficial to study its biology and evolution. Furthermore, we developed a full-length in vivo infectious cDNA clone of genotype 3b and showed its robustness and genetic stability in human-liver chimeric mice. This is, to our knowledge the first reported infectious cDNA clone of HCV genotype 3b and will provide a valuable tool to evaluate antivirals and neutralizing antibodies in vivo, as well as in the development of infectious cell culture systems required for further research.

Burden of liver cancer due to hepatitis C from 1990 to 2019 at the global, regional, and national levels

Background

Liver cancer due to hepatitis C (LCDHC) is one of the leading causes of cancer-related deaths worldwide, and the burden of LCDHC is increasing. We aimed to report the burden of LCDHC at the global, regional, and national levels in 204 countries from 1990 to 2019, stratified by etiology, sex, age, and Sociodemographic Index.

Methods

Data on LCDHC were available from the Global Burden of Disease, Injuries, and Risk Factors (GBD) study 2019. Numbers and age-standardized mortality, incidence, and disability-adjusted life year (DALY) rates per 100,000 population were estimated through a systematic analysis of modeled data from the GBD 2019 study. The trends in the LCDHC burden were assessed using the annual percentage change.

Results

Globally, in 2019, there were 152,225 new cases, 141,810 deaths, and 2,878,024 DALYs due to LCDHC. From 1990 to 2019, the number of incidences, mortality, and DALY cases increased by 80.68%, 67.50%, and 37.20%, respectively. However, the age-standardized incidence, mortality, and DALY rate had a decreasing trend during this period. In 2019, the highest age-standardized incidence rates (ASIRs) of LCDHC were found in high-income Asia Pacific, North Africa and the Middle East, and Central Asia. At the regional level, Mongolia, Egypt, and Japan had the three highest ASIRs in 2019. The incidence rates of LCDHC were higher in men and increased with age, with a peak incidence in the 95+ age group for women and the 85-89 age group for men in 2019. A nonlinear association was found between the age-standardized rates of LCDHC and sociodemographic index values at the regional and national levels.

Conclusions

Although the age-standardized rates of LCDHC have decreased, the absolute numbers of incident cases, deaths, and DALYs have increased, indicating that LCDHC remains a significant global burden. In addition, the burden of LCDHC varies geographically. Male and older adult/s individuals have a higher burden of LCDHC. Our findings provide insight into the global burden trend of LCDHC. Policymakers should establish appropriate methods to achieve the HCV elimination target by 2030 and reducing the burden of LCDHC.

Synthetic approaches and application of clinically approved small-molecule drugs to treat hepatitis

Hepatitis, a global public health concern, presents a significant burden on healthcare systems worldwide. Particularly, hepatitis B and C are viral infections that can lead to severe liver damage, cirrhosis, and even hepatocellular carcinoma (HCC). The urgency to combat these diseases has driven researchers to explore existing small-molecule drugs as potential therapeutics. This comprehensive review provides a systematic overview of synthetic routes to key antiviral agents used to manage hepatitis. Furthermore, it elucidates the mechanisms of action of these drugs, shedding light on their interference with viral replication and liver disease progression. The review also discusses the clinical applications of these drugs, including their use in combination therapies and various patient populations. By evaluating the synthetic pathways and clinical utility of these drugs, this review not only consolidates current knowledge but also highlights potential future directions for research and drug development in the fight against hepatitis, ultimately contributing to improved patient outcomes and reduced global disease burden.

Genetic and pharmacological perturbation of hepatitis-C virus entry

Hepatitis-C virus (HCV) chronically infects 58 million individuals worldwide with variable disease outcome. While a subfraction of individuals exposed to the virus clear the infection, the majority develop chronic infection if untreated. Another subfraction of chronically ill proceeds to severe liver disease. The underlying causes of this interindividual variability include genetic polymorphisms in interferon genes. Here, we review available data on the influence of genetic or pharmacological perturbation of HCV host dependency factors on the clinically observed interindividual differences in disease outcome. We focus on host factors mediating virus entry into human liver cells. We assess available data on genetic variants of the major entry factors scavenger receptor class-B type I, CD81, claudin-1, and occludin as well as pharmacological perturbation of these entry factors. We review cell culture experimental and clinical cohort study data and conclude that entry factor perturbation may contribute to disease outcome of hepatitis C.

Progression of fibrosis in liver transplant recipients with hepatitis C before and after sustained virologic response

BACKGROUND

Liver transplant (LT) recipients with untreated hepatitis C (HCV) are at risk for cirrhosis graft failure. The advent of direct acting antiviral agents (DAA) has improved outcomes in HCV.

AIMS

We aim to examine liver transplant outcomes and allograft fibrosis development/progression after sustained virologic response (SVR).

METHODS

We performed a retrospective cohort study of 226 consecutive liver transplant recipients with HCV from 2007 to 2018. The cohort was split into transplants pre (Group A) and post (Group B) 2014 to reflect the introduction of DAAs. Fibrosis was monitored with liver biopsy and non-invasive imaging.

RESULTS

Group B had significantly improved HCV treatment rates and earlier SVR compared to Group A, with a cumulative incidence rate of SVR at 2 years of 86.7% versus 15.4% (HR = .11, p < .001). Prior to achieving SVR, Group A demonstrated worsening of fibrosis stage per year (+.21, p < .001) whereas Group B showed minimal change on protocol annual biopsy (-.02, p = .80). After SVR, most patients were followed non-invasively and demonstrated stable or improved fibrosis stage over time. Patients undergoing transient elastography showed regression in fibrosis stage per year (-.19, p < .001).

CONCLUSION

HCV patients undergoing LT after 2014 had higher rates of SVR and improved clinically relevant transplant outcomes, namely less graft loss and death relating to HCV. Fibrosis progression halted or improved after SVR in both cohorts, suggesting that LT recipients with SVR do not require fibrosis monitoring even with established fibrosis prior to SVR.

Mouse Liver-Expressed Shiftless Is an Evolutionarily Conserved Antiviral Effector Restricting Human and Murine Hepaciviruses

Mice are refractory to infection with human-tropic hepatitis C virus (HCV), although distantly related rodent hepaciviruses (RHV) circulate in wild rodents. To investigate whether liver intrinsic host factors can exhibit broad restriction against these distantly related hepaciviruses, we focused on Shiftless (Shfl), an interferon (IFN)-regulated gene (IRG) which restricts HCV in humans. Unusually, and in contrast to selected classical IRGs, human and mouse SHFL orthologues (hSHFL and mSHFL, respectively) were highly expressed in hepatocytes in the absence of viral infection, weakly induced by IFN, and highly conserved at the amino acid level (>95%). Replication of both HCV and RHV subgenomic replicons was suppressed by ectopic expression of mSHFL in human or rodent hepatoma cell lines. Gene editing of endogenous mShfl in mouse liver tumor cells increased HCV replication and virion production. Colocalization of mSHFL protein with viral double-stranded RNA (dsRNA) intermediates was confirmed and could be ablated by mutational disruption of the SHFL zinc finger domain, concomitant with a loss of antiviral activity. In summary, these data point to an evolutionarily conserved function for this gene in humans and rodents: SHFL is an ancient antiviral effector which targets distantly related hepaciviruses via restriction of viral RNA replication. IMPORTANCE Viruses have evolved ways to evade or blunt innate cellular antiviral mechanisms within their cognate host species. However, these adaptations may fail when viruses infect new species and can therefore limit cross-species transmission. This may also prevent development of animal models for human-pathogenic viruses. HCV shows a narrow species tropism likely due to distinct human host factor usage and innate antiviral defenses limiting infection of nonhuman liver cells. Interferon (IFN)-regulated genes (IRGs) partially inhibit HCV infection of human cells by diverse mechanisms. Here, we show that mouse Shiftless (mSHFL), a protein that interferes with HCV replication factories, inhibits HCV replication and infection in human and mouse liver cells. We further report that the zinc finger domain of SHFL is important for viral restriction. These findings implicate mSHFL as a host factor that impairs HCV infection of mice and provide guidance for development of HCV animal models needed for vaccine development.

HIGH-DENSITY LIPOPROTEIN CHOLESTEROL AND SYSTEMIC ARTERIAL HYPERTENSION ARE ASSOCIATED WITH HEPATIC NECROINFLAMMATORY ACTIVITY IN PATIENTS WITH CHRONIC HEPATITIS C

•HDL cholesterol levels <60 mg/dL were independently associated with necroinflammatory activity in chronic hepatitis C (CHC). •CHC patients with hypertension are at an increased risk of developing necroinflammatory activity. •In patients with CHC, liver fibrosis was independently associated with old age, steatosis, and HDL-C <60 mg/dL. •Triglycerides levels ≥150 mg/dL were associated with lobular inflammatory activity in patients with CHC. Background - Approximately 71 million people are chronically infected with hepatitis C virus (HCV) worldwide. A significant number of these individuals will develop liver cirrhosis and/or hepatocellular carcinoma. Beyond the liver, there is a sizeable body of scientific evidence linking cardiovascular disease and chronic hepatitis C (CHC); however, the biological mechanisms behind the concurrence of these conditions have not been completely clarified yet. Objective - To evaluate associations between hepatic histology, clinical comorbidities and lipid profile in patients with CHC. To investigate associations between liver histology and demographic, nutritional, biochemical and virological parameters. Methods - Eight-five patients with CHC prospectively underwent hepatic biopsy. Liver fragments were obtained from each patient by percutaneous route using a Menghini needle. Fibrosis was evaluated according to the METAVIR scoring system, as follows: F0, no fibrosis; F1, fibrous portal expansion; F2, fibrous portal widening with few septa; F3, bridging fibrosis with architectural distortion; and F4, liver cirrhosis. The activity was classified based on the degree of lymphocyte infiltration and hepatocyte necrosis, from A0 to A3. The diagnosis of liver disease was based on clinical, biochemical, histological, and radiological methods. The data were analyzed by logistic regression models. Results - This cross-sectional study included 85 outpatients followed at the tertiary care ambulatory centre with a mean age of 57.2±10.7 years and 45 (52.9%) were females. There were 10 patients with cirrhosis. Patients with a METAVIR F3-F4 were significantly older (P=0.02) and had higher levels of ALT (P=0.0006), AST (P<0.0001), γ-GT (P=0.03) and bilirubin (P=0.001) and higher prothrombin time than patients with F0-F2 score. Albumin levels (P=0.01) were significantly lower in METAVIR F3-F4. Age (OR=1.09; 95%CI=1.02-1.16; P=0.02), steatosis (OR=4.03; 95%CI=1.05-15.45; P=0.04) and high-density lipoprotein cholesterol (HDL-C) <60 mg/dL (OR=7.67; 95%CI=1.71-34.49; P=0.008) were independently associated with fibrosis. Hypertension (OR=6.36; 95%CI=1.31-30.85; P=0.02) and HDL-C <60 mg/dL (OR=9.85; 95%CI=2.35-41.39; P=0.002) were independently associated with necroinflammatory activity. Hypertension (OR=6.94; 95%CI=1.92-25.05; P=0.003) and HDL-C <60 mg/dL (OR=3.94; 95%CI=1.27-12.3; P=0.02) were associated with interface inflammatory activity. Triglycerides (TG ≥150 mg/dL) remained associated with lobular inflammatory activity. Conclusion - cholesterol levels <60 mg/dL were independently associated with necroinflammatory activity in chronic hepatitis C. Patients with hypertension are at an increased risk of developing necroinflammatory activity.

Accelerating antiviral drug discovery: lessons from COVID-19

During the coronavirus disease 2019 (COVID-19) pandemic, a wave of rapid and collaborative drug discovery efforts took place in academia and industry, culminating in several therapeutics being discovered, approved and deployed in a 2-year time frame. This article summarizes the collective experience of several pharmaceutical companies and academic collaborations that were active in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antiviral discovery. We outline our opinions and experiences on key stages in the small-molecule drug discovery process: target selection, medicinal chemistry, antiviral assays, animal efficacy and attempts to pre-empt resistance. We propose strategies that could accelerate future efforts and argue that a key bottleneck is the lack of quality chemical probes around understudied viral targets, which would serve as a starting point for drug discovery. Considering the small size of the viral proteome, comprehensively building an arsenal of probes for proteins in viruses of pandemic concern is a worthwhile and tractable challenge for the community.

Recent advances in recurrent hepatocellular carcinoma therapy

Hepatocellular carcinoma (HCC) is the most prevalent form of primary liver cancer, accounting for 75%-85% of cases. Although treatments are given to cure early-stage HCC, up to 50%-70% of individuals may experience a relapse of the illness in the liver after 5 years. Research on the fundamental treatment modalities for recurrent HCC is moving significantly further. The precise selection of individuals for therapy strategies with established survival advantages is crucial to ensuring better outcomes. These strategies aim to minimize substantial morbidity, support good life quality, and enhance survival for patients with recurrent HCC. For individuals with recurring HCC after curative treatment, no approved therapeutic regimen is currently available. A recent study presented novel approaches, like immunotherapy and antiviral medication, to improve the prognosis of patients with recurring HCC with the apparent lack of data to guide the clinical treatment. The data supporting several neoadjuvant and adjuvant therapies for patients with recurring HCC are outlined in this review. We also discuss the potential for future clinical and translational investigations.

Outcomes of an automated alert system from Microbiology to link diagnosis to treatment in patients with hepatitis C virus

INTRODUCTION

simplification strategies for the care circuit of patients with hepatitis C virus (HCV) are key to achieve eradication. An electronic identification system was set up for HCV serology to link diagnosis to specialist management, aimed to reduce patient loss.

MATERIAL AND METHODS

a retrospective, single-center study was performed in patients with HCV identified from 15/3/2020 to 15/12/2021, using an alert system from Microbiology that notified specialists of positive cases. The patient was contacted and appointed a Fibroscan® and viral load measurement, with antiviral therapy prescribed on the same day. Origin, public health data, patient location rate and antiviral therapy prescription were recorded.

RESULTS

of 174 patients identified, 171 had positive viremia, with a mean age of 59.6 ± 15.9 years, 61.5 % were males and 81.2 % were Spanish nationals. Origin in the outpatient setting predominated (57.9 %, 99/171), particularly Primary Care (51/171), penitentiaries (21/171) and addiction units (14/171). Overall, 43.3 % (74/171) were aware of their diagnosis; 19.4 % (20/103) of patients had F3 fibrosis and 25.2 % (26/103) had F4 fibrosis. Also, 78.4 % (134/171) were deemed candidates for treatment. Of these, 74.6 % (100/134) were located and treatment was initiated, and all those who completed their treatment achieved a sustained viral response (96/96). This system managed 58.5 % (100/171) of the patients identified. The only association found between antiviral therapy and patient variables was comorbidities with being untreated (OR, 7.14; p ˂ 0.001).

CONCLUSIONS

this alert system allows to minimize patient loss in the care circuit and provides high rates of treated patients.

Association between Liver Stiffness and Liver-Related Events in HCV-Infected Patients after Successful Treatment with Direct-Acting Antivirals

Background and Objectives: Direct-acting antivirals (DAAs) are highly effective for the treatment of chronic hepatitis C virus (HCV) infection, but the risk of liver-related events and hepatocellular carcinoma (HCC) remains after successful therapy. We aimed to evaluate post-treatment changes in liver stiffness (LS) and identify a cut-off LS value for predicting such events in chronic HCV-infected patients receiving DAA. Materials and Methods: A total of 185 patients who had achieved sustained virologic response (SVR) after DAA therapy were included. Baseline characteristics and laboratory results were retrospectively abstracted. LS was measured by transient elastography at baseline, 12, 24, 48, and 96 weeks after SVR. FIB-4 index was assessed at baseline and 48 weeks after SVR. Development of liver-related events (hepatocellular carcinoma (HCC), portal-hypertension-related decompensation, listing for transplantation, and mortality) after SVR were identified. The association between liver fibrosis and the occurrence of liver-related events was analyzed using Cox regression analysis. Results: Significant differences in LS values were observed between baseline and 24, 48, 72, and 96 weeks after SVR. FIB-4 index at 48 weeks after SVR was significantly lower than the FIB-4 index at baseline. During the 41.6-month follow-up time, the incidence rates of all liver-related events and HCC were 2.36 and 1.17 per 100 person-years, respectively. Age, LS ≥8 kPa, and FIB-4 ≥1.35 at 48 weeks post-SVR were significantly associated with the occurrence of any liver-related events. By multivariate analysis, LS ≥8 kPa at 48 weeks post-SVR remained significantly associated with any liver-related events, with an adjusted hazard ratio (95%CI) of 5.04 (1.01-25.26), p = 0.049. Conclusions: Despite a significant reduction in LS after SVR, patients with LS ≥8 kPa at 48 weeks after SVR should be regularly monitored for liver-related complications, particularly HCC development.

Single-Ascending-Dose, Food-Effect, and Multiple-Dose Study of the Safety, Tolerability, and Pharmacokinetics of the Pangenotypic Anti-Hepatitis C Virus Drug Holybuvir in Healthy Chinese Subjects

Holybuvir is a novel pangenotypic hepatitis C virus NS5B inhibitor. This first in-human study aimed to evaluate the pharmacokinetics (PK), safety, and tolerability of holybuvir and its metabolites and the effect of food on the PK of holybuvir and its metabolites in healthy Chinese subjects. A total of 96 subjects were enrolled in this study which included (i) a single-ascending-dose (SAD) study (100 to 1,200 mg), (ii) a food-effect (FE) study (600 mg), and (iii) a multiple-dose (MD) study (400 and 600 mg once daily for 14 days). The results showed that single oral administration of holybuvir at doses up to 1,200 mg was well tolerated. Holybuvir was rapidly absorbed and metabolized in the human body, which was consistent with the characteristics of holybuvir as a prodrug. PK analysis showed that Cmax and area under the curve (AUC) increased with dose in no dose-proportional manner after a single-dose administration (100 to 1,200 mg). Although high-fat meals did change the PK of holybuvir and its metabolites, clinical significance of changes in PK parameters induced by eating a high-fat diet would be further confirmed. Following multiple-dose administration, accumulation of metabolites SH229M4 and SH229M5-sul was observed. The favorable PK and safety results support the further development of holybuvir for patients with HCV. (This study was registered at Chinadrugtrials.org under identifier CTR20170859.).

Antiviral Potential of the Genus Panax: An updated review on their effects and underlying mechanism of action

Viral infections are known as one of the major factors causing death. Ginseng is a medicinal plant that demonstrated a wide range of antiviral potential, and saponins are the major bioactive ingredients in the genus Panax with vast therapeutic potential. Studies focusing on the antiviral activity of the genus Panax plant-derived agents (extracts and saponins) and their mechanisms were identified and summarized, including contributions mainly from January 2016 until January 2022. P. ginseng, P. notoginseng, and P. quinquefolius were included in the review as valuable medicinal herbs against infections with 14 types of viruses. Reports from 9 extracts and 12 bioactive saponins were included, with 6 types of protopanaxadiol (PPD) ginsenosides and 6 types of protopanaxatriol (PPT) ginsenosides. The mechanisms mainly involved the inhibition of viral attachment and replication, the modulation of immune response by regulating signaling pathways, including the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway, cystathionine γ-lyase (CSE)/hydrogen sulfide (H₂S) pathway, phosphoinositide-dependent kinase-1 (PDK1)/ protein kinase B (Akt) signaling pathway, c-Jun N-terminal kinase (JNK)/activator protein-1 (AP-1) pathway, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. This review includes detailed information about the mentioned antiviral effects of the genus Panax extracts and saponins in vitro and in vivo, and in human clinical trials, which provides a scientific basis for ginseng as an adjunctive therapeutic drug or nutraceutical.

Improved Survival After Liver Transplantation for Patients With Human Immunodeficiency Virus (HIV) and HIV/Hepatitis C Virus Coinfection in the Integrase Strand Transfer Inhibitor and Direct-Acting Antiviral Eras

BACKGROUND

People with human immunodeficiency virus (HIV) with and without hepatitis C virus (HCV) coinfection had poor outcomes after liver transplant (LT). Integrase strand transfer inhibitors (INSTIs) and direct-acting antivirals (DAAs) have changed the treatment landscape for HIV and HCV, respectively, but their impact on LT outcomes remains unclear.

METHODS

This retrospective analysis of adults with HIV monoinfection (n = 246) and HIV/HCV coinfection (n = 286) who received LT compared mortality in patients with HIV who received LT before versus after approval of INSTIs and in patients with HIV/HCV coinfection who received LT before versus after approval of DAAs. In secondary analysis, we compared the outcomes in the different eras with those of propensity score-matched control cohorts of LT recipients without HIV or HCV infection.

RESULTS

LT recipients with HIV monoinfection did not experience a significant improvement in survival between the pre-INSTI and INSTI recipients with HIV (adjusted hazard ratio [aHR], 0.70 [95% confidence interval {CI}, .36-1.34]). However, recipients with HIV/HCV coinfection in the DAA era had a 47% reduction (aHR, 0.53 [95% CI, .31-9.2] in 1-year mortality compared with coinfected recipients in the pre-DAA era. Compared to recipients without HIV or HCV, HIV-monoinfected recipients had higher mortality during the pre-INSTI era, but survival was comparable between groups during the INSTI era. HIV/HCV-coinfected recipients also experienced comparable survival during the DAA era compared to recipients without HCV or HIV.

CONCLUSIONS

Post-LT survival for people with HIV monoinfection and HIV/HCV coinfection has improved with the introduction of INSTI and DAA therapy, suggesting that LT has become safer in these populations.

Longitudinal assessment of HCV core antigen kinetics to monitor therapeutic response in the age of DAAs

BACKGROUND

In the economy of therapeutic monitoring, an affordable viral marker is essential in the era of direct-acting antivirals (DAAs). We elucidated the kinetics of HCVcAg to delineate its precise role in monitoring therapeutic response.

METHODS

In this longitudinal study, 3208 patients were tested for HCV RNA. A total of 423 patients were started on DAAs. Treatment response and kinetics of HCVcAg/RNA were assessed in treatment-naïve (n = 383) and previously treated (n = 40) patients with follow-up for 2 years.

RESULTS

After the initiation of DAAs, the rate of relapse was significantly higher in the previously treated group than naive group [12.5% (5/40) Vs 2% (7/383), p<0.0001]. The response rate at RVR was significantly higher with HCVcAg than RNA in both groups (p<0.02). The kinetics of HCVcAg and RNA were significantly different at ETR and SVR12 in the naïve (p<0.04), but similar at all therapeutic points in the previously treated group. The correlation between HCVcAg and RNA was good at baseline, ETR and SVR, except RVR in both groups (r>0.6; p<0.0001). Furthermore, HCV genotypes, treatment regimen, CTP (<7/≥7) and MELD (<15/≥15) did not influence the therapeutic response and the viral replication kinetics (p>0.05).

CONCLUSIONS

It is the first longitudinal study from India shows that the response rate and kinetics of HCVcAg are comparable to HCV RNA for an extended duration, except at RVR, irrespective of the HCV genotypes, treatment regimen, and liver disease severity. Hence, HCVcAg can be considered as a pragmatic marker to monitor therapeutic response and predict relapse in the era of DAAs.

Efficacy of a comprehensive strategy for the detection and treatment of hepatitis C infection in a population attending addiction centers

Background and aims

The burden hepatitis C infection in people with history or current drug use suppose a high risk of hepatic complications and transmission infectious disease. This population is poor linked to heath system and is difficult to achieve them and support treatment because they have high rates of lost follow-up. Our aim was to evaluate an intervention for the diagnosis and treatment of chronic hepatitis C and HIV in this population.

Methods

Six-hundred and eighty-three people attended in Drugs and Addictions Centers (DAC) were asked to participate in health counseling and provide blood sample for test HCV, HIV, and syphilis from April 2019 to June 2020. Totally 556 subjects were surveyed and tested. All of them were assigned to a patient navigation program to improve health education and linking to the sanitary system. Hepatitis C infection patients were evaluated in an ampliated medical consult to evaluate hepatic stage with transient liver elastography and initiated Direct Acting Antivirals to achieve Sustained Viral Response.

Results

Of the 556 patients who agreed to participate in the study, 33 (5.9%) had active HCV infection. Of the 33 patients infected with HCV, three were lost to follow-up once the diagnosis of HCV infection was made. Twenty-eight patients (93.3%) completed treatment and 26 achieved Sustained Viral Response (78.8%). Of the 30 patients, seven (23.3%) had advanced fibrosis, and of these, four (16.6%) had liver cirrhosis. One of the cirrhotic patients had hepatic space-occupying lesions at the baseline evaluation and was diagnosed with hepatocarcinoma.

Conclusions

Our study suggests that the implementation of strategies based on personalized intervention models can contribute to the control of HCV infection in DAC users.

Hepatocellular carcinoma and hepatitis C virus treatments: The bold and the beautiful

The occurrence of hepatocellular carcinoma (HCC) is one of the most serious complications of hepatitis C virus (HCV) infection. Recently, effective antiviral medications have made sustained viral response (SVR) or cure a realistic therapeutic goal for most chronic HCV patients. Given HCV's tumorigenic propensity, it is not surprising that achieving SVR is helpful in preventing HCC. This review briefly summarizes and discusses the existing evidence on the relationship between hepatic carcinogenesis and viral eradication by antivirals, which is mainly divided into interferon-based and direct-acting antivirals (DAAs) based therapy. DAAs have changed the treatment landscape of chronic HCV, reaching high rates of SVR even in patients with advanced cirrhosis, with few contraindications and little side effects. Although some early reports suggested that DAA treatment increased the chance of HCC occurrence, more subsequent observational studies have refuted this theory. The probability of HCC recurrence after HCV eradication appears to be decreasing over time following SVR. Despite virological suppression/cure, individuals with liver cirrhosis are still at risk of HCC and should be monitored. There is a considerable need for markers/scores to predict the long-term risk of HCC in patients with HCV-related liver disease who attain SVR with direct-acting antivirals.

Regions of hepatitis C virus E2 required for membrane association

Hepatitis C virus (HCV) uses a hybrid entry mechanism. Current structural data suggest that upon exposure to low pH and Cluster of Differentiation 81 (CD81), the amino terminus of envelope glycoprotein E2 becomes ordered and releases an internal loop with two invariant aromatic residues into the host membrane. Here, we present the structure of an amino-terminally truncated E2 with the membrane binding loop in a bent conformation and the aromatic side chains sequestered. Comparison with three previously reported E2 structures with the same Fab indicates that this internal loop is flexible, and that local context influences the exposure of hydrophobic residues. Biochemical assays show that the amino-terminally truncated E2 lacks the baseline membrane-binding capacity of the E2 ectodomain. Thus, the amino terminal region is a critical determinant for both CD81 and membrane interaction. These results provide new insights into the HCV entry mechanism.

Repeated Measurement of FIB-4 to Predict Long-Term Risk of HCC Development Up to 10 Years After SVR

Purpose

It is unclear whether and how the long-term risk of hepatocellular carcinoma (HCC) will change in hepatitis C virus (HCV) infected patients who have reached sustained virologic response (SVR) with direct-acting antivirals (DAA). In this study, we assessed the long-term risk of HCC up to 10 years after SVR using fibrosis 4 score (FIB-4) and its dynamic changes.

Patients and Methods

A total of 701 DAA-treated patients who achieved SVR between January 2012 to October 2020 were enrolled in the study. The FIB-4 score of each patient was measured at the date of SVR and each follow-up visit annually. Patients were followed until December 31, 2021, with the longest follow-up time being 9.82 years.

Results

Following SVR, 27 cases of HCC were observed. The annual incidence rate of HCC remained stable with no obvious downward trend. Patients with a FIB-4 >3.25 at baseline or anytime during follow-up were at a higher risk of developing HCC than those whose FIB-4 remained below 3.25. Patients with cirrhosis and patients with no cirrhosis but a FIB-4 >3.25 were at higher risk of developing HCC than patients with no cirrhosis and a FIB-4 ≦3.25.

Conclusion

FIB-4 >3.25 measured at SVR or any time post-SVR was associated with HCC risks. The repeated measurement of FIB-4 revealed a better predictive ability of HCC risks than the simple measurement of FIB-4 at baseline. The additional stratification of patients by combining FIB-4 and cirrhosis leads to more accurately identifying high-risk patients. Surveillance of HCC is recommended for virologically cured patients with a FIB-4 >3.25 at SVR or anytime afterward and patients diagnosed with cirrhosis.

Effectiveness and safety of generic and brand direct acting antivirals for treatment of chronic hepatitis C

BACKGROUND

Direct acting antivirals (DAAs) are a very effective treatment for hepatitis C virus (HCV). However, brand DAAs are expensive. The licensing of cheaper generic DAAs may address this issue, but there is a lack of clinical studies comparing the efficacy of generic vs brand DAA formulations.

AIM

To compare the efficacy and safety of generic against brand DAAs for chronic hepatitis C treatment in Bahrain.

METHODS

This was a retrospective observational study involving 289 patients with chronic HCV infection during 2016 to 2018. There were 149 patients who were treated with brand DAAs, while 140 patients were treated with generic DAAs. Commonly used DAAs were Ombitasvir/Paritaprevir/Ritonavir ± Dasabuvir ± Ribavirin, and Sofosbuvir/Daclatasvir ± Ribavirin. SVR at 12 wk post treatment was the main outcome variable.

RESULTS

Overall, 87 patients (30.1%) had cirrhosis and 68.2% had genotype 1 HCV infection. At 12 wk post treatment, SVR was achieved by 271 (93.8%) of the patients. In patients who were treated with generic medications, 134 (95.7%) achieved SVR at 12 wk post treatment, compared to 137 (91.9%) among those treated with brand medications (P = 0.19). Having cirrhosis [odds ratio (OR): 9.41, 95% confidence interval (CI): 2.47–35.84] and having HCV genotype 3 (OR: 3.56, 95%CI: 1.03–12.38) were significant independent predictors of not achieving SVR. Alanine transaminase, gamma-glutamyl transpeptidase, and total bilirubin levels decreased significantly following therapy with both generic and brand DAAs.

CONCLUSION

Generic and brand DAAs demonstrate comparable effectiveness in the treatment of chronic hepatitis C patients. Both are safe and equally effective in improving biochemical markers of hepatic inflammation.

Assessment of alteration in antiviral plasma concentration across dialysis days: computational and analytical study

Aim: Protein-bound uremic toxins (PBUTs) may displace drugs from the plasma proteins and render them more liable to clearance. This study aims to investigate the possible interplay between PBUTs and directly acting antivirals (DAAs). Methods: PBUT plasma protein binding was compared to those of paritaprevir (PRT), ombitasivir (OMB) and ritonavir (RTV) in silico to assess the possible competitive displacement. The three drugs were LC-MS/MS determined in seven patients across dialysis and non-dialysis days and results were compared. Results & conclusion: Results showed that the PBUT exhibited a lower binding than DAA reducing the liability of their competitive displacement. This was echoed by an unaltered plasma concentration across dialysis days. Results may indicate that PBUT accumulation may have limited effect on disposition of DAA.

Fibrosis-4 index efficiently predicts chronic hepatitis and liver cirrhosis development based on a large-scale data of general population in Japan

A non-invasive method to evaluate the fibrosis stage and the risk stratification of non-alcoholic fatty liver disease (NAFLD) is required. A total of 416,066 generally healthy subjects who underwent health check-ups between 1990 and 2019 were investigated. Fatty liver prevalence greatly increased from the 1990s (21.9%) to the 2000s (37.1%) but showed no considerable change between 2001-2010 (39.2%) and 2011-2019 (35.5%). During the 30 years, the rate of high FIB-4 index (≥2.67) and mean body mass index (BMI) did not markedly change. Fatty liver was significantly associated with BMI, but not with alcohol intake or FIB-4 index. Cox regression analyses for development of chronic hepatitis or liver cirrhosis identified that the risk of developing chronic hepatitis and liver cirrhosis was higher in subjects without fatty liver than in those with it (hazard ratio [HR]=0.09; 95% confidence interval [CI], 0.03-0.22, p <0.001 and HR=0.04; 95% CI, 0.01-0.26, p =0.001, respectively), and much larger in subjects with a high FIB-4 index (≥ 2.67) than in those without it (HR=78.6; 95% CI, 29.0-213.1, p <0.001 and HR=5950.7; 95% CI,761.7-46,491.4, p <0.001, respectively). Adjusted survival curves for Cox proportional hazards regression further reinforced these results. In conclusion, the FIB-4 index is a useful indicator of chronic hepatitis and liver cirrhosis development in the general population.

Novel HCV Genotype 4d Infectious Systems and Assessment of Direct-Acting Antivirals and Antibody Neutralization

Hepatitis C virus (HCV) genotype 4 is highly prevalent in the Middle East and parts of Africa. Subtype 4d has recently spread among high-risk groups in Europe. However, 4d infectious culture systems are not available, hampering studies of drugs, as well as neutralizing antibodies relevant for HCV vaccine development. We determined the consensus 4d sequence from a chronic hepatitis C patient by next-generation sequencing, generated a full-length clone thereof (pDH13), and demonstrated that pDH13 RNA-transcripts were viable in the human-liver chimeric mouse model, but not in Huh7.5 cells. However, a JFH1-based DH13 Core-NS5A 4d clone encoding A1671S, T1785V, and D2411G was viable in Huh7.5 cells, with efficient growth after inclusion of 10 additional substitutions [4d(C5A)-13m]. The efficacies of NS3/4A protease- and NS5A- inhibitors against genotypes 4a and 4d were similar, except for ledipasvir, which is less potent against 4d. Compared to 4a, the 4d(C5A)-13m virus was more sensitive to neutralizing monoclonal antibodies AR3A and AR5A, as well as 4a and 4d patient plasma antibodies. In conclusion, we developed the first genotype 4d infectious culture system enabling DAA efficacy testing and antibody neutralization assessment critical to optimization of DAA treatments in the clinic and for vaccine design to combat the HCV epidemic.

Results of a Model of Delivering Hepatitis C Care in a Homeless Metropolitan Population in England

INTRODUCTION

Given the hepatitis C virus (HCV) burden and despite curative treatments, more efforts focused on scaling-up testing and treatment in homeless populations are needed. This project aimed to implement education and flexible on-site HCV testing, treatment, and follow-up for a homeless population in south London and to evaluate engagement, therapy initiation, and cure rates.

METHODS

A mobile unit (van) for on-site HCV education, screening, treatment, and follow-up was placed on the street in a well-known homeless population areas from January 2018 to September 2021. Homeless was defined as living in temporary housing (hostel/hotel-based) or living on the street (street-based). Sociodemographic status, risk factors, comorbidities, concomitant medication, and data related with HCV treatment were recorded. Univariable and multivariable modeling were performed for treatment initiation and sustained virological response (SVR).

RESULTS

Nine hundred forty homeless people were identified and 99.3% participated. 56.2% were street-based, 243 (26%) tested positive for HCV antibody, and 162 (17.4%) were viremic. Those with detectable HCV RNA had significantly more frequent psychiatric disorders, active substance use disorders, were on opioid agonist treatment, had advanced fibrosis, and had lower rates of previous treatment in comparison with undetectable HCV RNA. Overall treatment initiation was 70.4% and SVR was 72.8%. In the multivariable analysis, being screened in temporary housing (odds ratio [OR] 3.166; P = 0.002) and having opioid agonist treatment (OR 3.137; P = 0.004) were positively associated with treatment initiation. HCV treatment adherence (OR 26.552; P < 0.001) was the only factor associated with achieving SVR.

DISCUSSION

Promoting education and having flexible and reflex mobile on-site testing and treatment for HCV in the homeless population improve engagement with the health care system, meaning higher rates of treatment initiation and SVR. However, street-based homeless population not linked with harm reduction services are less likely to initiate HCV treatment, highlighting an urgent need for a broad health inclusion system.

Integrating Management of Hepatitis C Infection into Primary Care: the Key to Hepatitis C Elimination Efforts

Elimination of hepatitis C virus (HCV), a leading cause of liver disease in the USA and globally, has been made possible with the advent of highly efficacious direct acting antivirals (DAAs). DAA regimens offer cure of HCV with 8-12 weeks of a well-tolerated once daily therapy. With increasingly straightforward diagnostic and treatment algorithms, HCV infection can be managed not only by specialists, but also by primary care providers. Engaging primary care providers greatly increases capacity to diagnose and treat chronic HCV and ultimately make HCV elimination a reality. However, barriers remain at each step in the HCV cascade of care from screening to evaluation and treatment. Since primary care is at the forefront of patient contact, it represents the ideal place to concentrate efforts to identify barriers and implement solutions to achieve universal HCV screening and increase curative treatment.

Barriers to hepatitis C virus infection in mice

Hepatitis C virus (HCV) is unable to infect mice, a fact that has severely limited their use as small-animal models for HCV pathogenesis and as tools for HCV vaccine development. HCV is blocked at various stages of its life cycle in mouse cells, due to incompatibility with host factors, the presence of dominant restriction factors, and effective immune responses. Molecular mechanisms for several such blocks have been characterized. The stepwise understanding of these limitations in mice will enable the development of an immunocompetent mouse that can fully support HCV infection and exhibit disease similar to that of infected humans.

Identification of potent inhibitors of SARS-CoV-2 infection by combined pharmacological evaluation and cellular network prioritization

Pharmacologically active compounds with known biological targets were evaluated for inhibition of SARS-CoV-2 infection in cell and tissue models to help identify potent classes of active small molecules and to better understand host-virus interactions. We evaluated 6,710 clinical and preclinical compounds targeting 2,183 host proteins by immunocytofluorescence-based screening to identify SARS-CoV-2 infection inhibitors. Computationally integrating relationships between small molecule structure, dose-response antiviral activity, host target, and cell interactome produced cellular networks important for infection. This analysis revealed 389 small molecules with micromolar to low nanomolar activities, representing >12 scaffold classes and 813 host targets. Representatives were evaluated for mechanism of action in stable and primary human cell models with SARS-CoV-2 variants and MERS-CoV. One promising candidate, obatoclax, significantly reduced SARS-CoV-2 viral lung load in mice. Ultimately, this work establishes a rigorous approach for future pharmacological and computational identification of host factor dependencies and treatments for viral diseases.

Perivascular Mesenchymal Stem/Stromal Cells, an Immune Privileged Niche for Viruses?

Mesenchymal stem cells (MSCs) play a critical role in response to stress such as infection. They initiate the removal of cell debris, exert major immunoregulatory activities, control pathogens, and lead to a remodeling/scarring phase. Thus, host-derived ‘danger’ factors released from damaged/infected cells (called alarmins, e.g., HMGB1, ATP, DNA) as well as pathogen-associated molecular patterns (LPS, single strand RNA) can activate MSCs located in the parenchyma and around vessels to upregulate the expression of growth factors and chemoattractant molecules that influence immune cell recruitment and stem cell mobilization. MSC, in an ultimate contribution to tissue repair, may also directly trans- or de-differentiate into specific cellular phenotypes such as osteoblasts, chondrocytes, lipofibroblasts, myofibroblasts, Schwann cells, and they may somehow recapitulate their neural crest embryonic origin. Failure to terminate such repair processes induces pathological scarring, termed fibrosis, or vascular calcification. Interestingly, many viruses and particularly those associated to chronic infection and inflammation may hijack and polarize MSC’s immune regulatory activities. Several reports argue that MSC may constitute immune privileged sanctuaries for viruses and contributing to long-lasting effects posing infectious challenges, such as viruses rebounding in immunocompromised patients or following regenerative medicine therapies using MSC. We will herein review the capacity of several viruses not only to infect but also to polarize directly or indirectly the functions of MSC (immunoregulation, differentiation potential, and tissue repair) in clinical settings.

Molecular Epidemiology and Baseline Resistance of Hepatitis C Virus to Direct Acting Antivirals in Croatia

Molecular epidemiology of hepatitis C virus (HCV) is exceptionally complex due to the highly diverse HCV genome. Genetic diversity, transmission dynamics, and epidemic history of the most common HCV genotypes were inferred by population sequencing of the HCV NS3, NS5A, and NS5B region followed by phylogenetic and phylodynamic analysis. The results of this research suggest high overall prevalence of baseline NS3 resistance associate substitutions (RAS) (33.0%), moderate prevalence of NS5A RAS (13.7%), and low prevalence of nucleoside inhibitor NS5B RAS (8.3%). Prevalence of RAS significantly differed according to HCV genotype, with the highest prevalence of baseline resistance to NS3 inhibitors and NS5A inhibitors observed in HCV subtype 1a (68.8%) and subtype 1b (21.3%), respectively. Phylogenetic tree reconstructions showed two distinct clades within the subtype 1a, clade I (62.4%) and clade II (37.6%). NS3 RAS were preferentially associated with clade I. Phylogenetic analysis demonstrated that 27 (9.0%) HCV sequences had a presumed epidemiological link with another sequence and classified into 13 transmission pairs or clusters which were predominantly comprised of subtype 3a viruses and commonly detected among intravenous drug users (IDU). Phylodynamic analyses highlighted an exponential increase in subtype 1a and 3a effective population size in the late 20th century, which is a period associated with an explosive increase in the number of IDU in Croatia.

Analysis of direct-acting antiviral-resistant hepatitis C virus haplotype diversity by single-molecule and long-read sequencing

The method of analyzing individual resistant hepatitis C virus (HCV) by a combination of haplotyping and resistance-associated substitution (RAS) has not been fully elucidated because conventional sequencing has only yielded short and fragmented viral genomes. We performed haplotype analysis of HCV mutations in 12 asunaprevir/daclatasvir treatment-failure cases using the Oxford Nanopore sequencer. This enabled single-molecule long-read sequencing using rolling circle amplification (RCA) for correction of the sequencing error. RCA of the circularized reverse-transcription polymerase chain reaction products successfully produced DNA longer than 30 kilobase pairs (kb) containing multiple tandem repeats of a target 3 kb HCV genome. The long-read sequencing of these RCA products could determine the original sequence of the target single molecule as the consensus nucleotide sequence of the tandem repeats and revealed the presence of multiple viral haplotypes with the combination of various mutations in each host. In addition to already known signature RASs, such as NS3-D168 and NS5A-L31/Y93, there were various RASs specific to a different haplotype after treatment failure. The distribution of viral haplotype changed over time; some haplotypes disappeared without acquiring resistant mutations, and other haplotypes, which were not observed before treatment, appeared after treatment. Conclusion: The combination of various mutations other than the known signature RAS was suggested to influence the kinetics of individual HCV quasispecies in the direct-acting antiviral treatment. HCV haplotype dynamic analysis will provide novel information on the role of HCV diversity within the host, which will be useful for elucidating the pathological mechanism of HCV-related diseases.

Safety and Antiviral Activity of EGFR Inhibition by Erlotinib in Chronic Hepatitis C Patients: A Phase Ib Randomized Controlled Trial

INTRODUCTION

Significant hepatocellular carcinoma (HCC) risk persists after chronic hepatitis C (CHC) cure. Preclinical studies have shown that erlotinib, an oral epidermal growth factor receptor (EGFR) inhibitor, has an antiviral activity and HCC chemopreventive effect. Erlotinib is metabolized in the liver, and its safety in patients with CHC is unknown. This study aimed to assess the safety and antiviral activity of erlotinib in patients with CHC.

METHODS

In this investigator-initiated dose-escalation phase Ib prospective randomized double-blind placebo-controlled study, noncirrhotic hepatitis C virus (HCV) patients received placebo or erlotinib (50 or 100 mg/d) for 14 days with a placebo-erlotinib ratio of 1:3. Primary end points were safety and viral load reduction at the end of treatment (EOT). The secondary end point was viral load reduction 14 days after EOT.

RESULTS

This study analyzed data of 3 patients receiving placebo, 3 patients receiving erlotinib 50 mg/d, and 3 patients receiving erlotinib 100 mg/d. One grade 3 adverse event was reported in the placebo group (liver enzymes elevation), leading to treatment discontinuation and patient replacement, and 1 in the erlotinib 100 mg/d group (pericarditis), which was not considered to be treatment-related. Grade 2 skin rash was observed in 1 erlotinib 100 mg/d patient. No significant HCV-RNA level reduction was noted during treatment, but 2 of the 3 patients in the erlotinib 100 mg/d group showed a decrease of >0.5 log HCV-RNA 14 days after EOT.

DISCUSSION

Erlotinib demonstrated to be safe in noncirrhotic CHC patients. An antiviral activity at 100 mg/d confirms a functional role of EGFR as an HCV host factor in patients. These results provide perspectives to further study erlotinib as an HCC chemopreventive agent in patients with CHC.

Emergence and Persistence of Resistance-Associated Substitutions in HCV GT3 Patients Failing Direct-Acting Antivirals

Background: The hepatitis C virus has a high mutation rate, which results in the emergence of resistance-associated substitutions (RASs). Despite direct-acting antivirals (DAAs) efforts to treat chronically infected HCV genotype 3 (GT3) patients, there are concerns about the emergence and persistence of RASs in DAA failures. The objective of this study was to determine the prevalence of clinically relevant RASs in HCV NS5A and NS5B regions before and after treatment to better understand the role of RASs in treatment failures. Methods: Viral RNA was extracted before and after treatment from serum samples. NS5A and NS5B regions of HCV were amplified by nested PCR, followed by Sanger sequencing. The nucleotide sequences were aligned against HCV GT3 reference sequences, and amino acid substitutions were analyzed using the geno2pheno [hcv] webserver. Results: A total of 76 patients failing DAA therapy were stratified from the cohort of 1388. RASs were detected at the baseline in 15/76 patients and at relapse in 20/76 patients with cirrhosis and previously treated with interferons. The most prevalent NS5A RAS was Y93H found in all treatment-failing patients (14/54 in DCV vs. 6/22 in VEL), followed by A62S/T and A30K. No RASs were identified in NS5B. RASs that were present at the baseline persisted through the 24-week follow-up period and were enriched with emerging RASs during the treatment. The presence of RASs may be one of the causes of treatment failures in 26.3% of patients. Amino acid substitutions were present at the baseline in most of the patients with RASs against NS5A inhibitors. Patients with the baseline Y93H and/or A30K relapse more frequently than patients harboring A62S/T. Conclusion: Treatment-failing patients harbored NS5A RASs, and the most frequent were A30K (5/20), A62S/T (20/20), and Y93H (20/20). Direct resistance testing is recommended for optimizing re-treatment strategies in treatment-failing patients.

Monte Carlo Method and GA-MLR-Based QSAR Modeling of NS5A Inhibitors against the Hepatitis C Virus

Hepatitis C virus (HCV) is a serious disease that threatens human health. Despite consistent efforts to inhibit the virus, it has infected more than 58 million people, with 300,000 deaths per year. The HCV nonstructural protein NS5A plays a critical role in the viral life cycle, as it is a major contributor to the viral replication and assembly processes. Therefore, its importance is evident in all currently approved HCV combination treatments. The present study identifies new potential compounds for possible medical use against HCV using the quantitative structure–activity relationship (QSAR). In this context, a set of 36 NS5A inhibitors was used to build QSAR models using genetic algorithm multiple linear regression (GA-MLR) and Monte Carlo optimization and were implemented in the software CORAL. The Monte Carlo method was used to build QSAR models using SMILES-based optimal descriptors. Four splits were performed and 24 QSAR models were developed and verified through internal and external validation. The model created for split 3 produced a higher value of the determination coefficients using the validation set (R2 = 0.991 and Q2 = 0.943). In addition, this model provides interesting information about the structural features responsible for the increase and decrease of inhibitory activity, which were used to develop eight novel NS5A inhibitors. The constructed GA-MLR model with satisfactory statistical parameters (R2 = 0.915 and Q2 = 0.941) confirmed the predicted inhibitory activity for these compounds. The Absorption, Distribution, Metabolism, Elimination, and Toxicity (ADMET) predictions showed that the newly designed compounds were nontoxic and exhibited acceptable pharmacological properties. These results could accelerate the process of discovering new drugs against HCV.

A Missed Opportunity: The Impact of Hepatitis C Treatment Prior to Total Knee Arthroplasty on Postoperative Complications

BACKGROUND

Hepatitis C (HCV) is undertreated and increasing in prevalence. Its influence on outcomes following total knee arthroplasty (TKA) remains unclear. The purpose of this study is to examine the impact of HCV and prearthroplasty antiviral treatment on postoperative complications following TKA.

METHODS

A retrospective matched cohort study was conducted using an administrative claims database to compare postoperative complication rates following TKA for (1) patients with vs without HCV and (2) among patients with HCV, patients with antiviral treatment before TKA vs no treatment. In total, 6971 patients with HCV were matched 1:4 with 27,884 controls without HCV, and 708 HCV patients with antiviral treatment before TKA were matched 1:2 with 1416 HCV patients without treatment. Rates of joint complications at 1 and 2 years postoperatively were compared via multivariable logistic regression.

RESULTS

The HCV cohort exhibited significantly higher risk of prosthetic joint infection (PJI) than controls at both 1 (4.1 vs 2.1%; odds ratio [OR] 1.58) and 2 years (5.0% vs 2.7%; OR 1.55) postoperatively. Rates of revision TKA were also significantly higher for HCV patients at 1 (2.8% vs 1.8%; OR 1.40) and 2 years (4.1% vs 2.9%; OR 1.30). HCV patients with prearthroplasty antiviral treatment exhibited significantly lower risk of PJI at 1 (2.1% vs 4.1%; OR 0.50) and 2 years (2.7% vs 5.1%, OR 0.51) compared to patients without treatment.

CONCLUSION

Patients with HCV have significantly increased risk of PJI and revision arthroplasty following TKA. Antiviral treatment before TKA significantly decreases the risk of PJI postoperatively.

LEVEL OF EVIDENCE

Level III.