Search Results (152)

Background: Hepatitis B and C viral infections remain a significant global health challenge, despite the implementation of an effective direct-acting antiviral (DAAs) and nucleos(t)ide analogues (NAs). Current HBV therapy is not curative as stopping therapy usually leads to active disease in most patients requiring long-term treatment. Although current HCV-DAAs are highly effective they fall short due to arising drug-resistance and have limited ability to avert re-infections. Furthermore, current HCV DAA treatments lead to the reactivation of occult HBV infection, compromising the effectiveness of current antiviral therapies, and increasing the risk of severe liver complications like cirrhosis and hepatocellular carcinoma. In addition, current treatments do not restore the immune dysfunction, a characteristic of chronic HBV infection. Given the global burden of disease, there is an urgent need for more effective therapy that can shorten the duration of treatment and achieve high rates of HBsAg reduction. Combining an antiviral to reduce viral antigen burden and an immunomodulator to boost the immune response could provide an effective treatment for HBV/HCV infections. Methods: In this study, we explored the potential of a novel bacterial therapeutic agent, heat-killed Caulobacter crescentus (HKCC), as an alternative and/or adjunct host-based therapy for HCV and HBV infections. Here, we have investigated the antiviral effects of the HKCC-stimulated human PBMCs using in vitro HCV and HBV infection models to assess viral replication, viral relapse responses, protein expression, and cytotoxicity. Results: Our findings reveal that HKCC induced a multi-functional cytokine response (IFN, TNF, IL-2, IL-10, IL-6, IL-17A, and IL-22) in PBMCs obtained from multiple healthy donors. Supernatants collected from these HKCC-stimulated human PBMCs, alone and in combination with antivirals, strikingly inhibited HCV replication and viral relapse responses without inducing any cytotoxic effects on HCV-1a replicon cells. In addition, these PBMC supernatants, with or without antivirals, led to the suppression of HBV DNA replication and inhibited HBsAg and HBeAg production in HepG 2.2.15 cells. Conclusions: In conclusion, HKCC is a promising candidate for eliminating HBV and HCV infections, and warrants further investigation to potentially contribute to the development of a novel host-based immunotherapy. Full article

Background/Objectives: Chronic hepatitis C (CHC) infection is an independent risk factor for developing type 2 diabetes mellitus (T2DM). However, it is unknown if antiviral treatment, especially with direct-acting antivirals (DAAs), changes long-term glycemic outcomes. Methods: We conducted a retrospective comparative cohort study of 2489 patients with chronic hepatitis C (CHC) in southern Taiwan between 2005 and 2022 who underwent treatment with either an interferon (IFN)-based or direct-acting antiviral agent (DAA) regimen. Given the distinct treatment eras of IFN and DAA therapies, potential temporal confounding was considered in the analytical design. Patients with existing diabetes or co-infections were excluded. The incidence of new-onset T2DM and longitudinal HbA1c levels were compared between treatment groups over a mean follow-up period of 2.56 years. Results: DAA-treated patients demonstrated a lower crude cumulative incidence of T2DM compared with IFN-treated patients (2.46% vs. 6.91%). However, adjusted analyses did not demonstrate a statistically significant difference between treatment groups. The cumulative risk appeared to plateau after the third year among DAA recipients. Post-therapy, HbA1c levels remained stable in both groups at between 5.5% and 6.5% over as long as five years. Splitting regression revealed that BMI ≥ 30 kg/m², and not treatment type or achieved SVR, was an independent T2DM risk factor. The lowest rates of diabetes incidence were associated with pan-genotypic DAA regimens. Conclusions: DAA-treated patients showed lower crude T2DM incidence than IFN-treated patients; however, this difference was not consistently significant after adjustment for baseline factors. Viral eradication may be associated with favorable metabolic trends; however, the present findings do not establish a causal protective effect against incident T2DM. While increased BMI remained an independent predictor of post-treatment diabetes risk. Full article

Viruses cause a great number of infectious diseases with medical, veterinary, agricultural, social and economic impact. Their unique mechanisms to spread, overcome and resist the existing countermeasures require innovative and smart antiviral strategies such as the effective disinfection of enclosed environments with ensured broad-spectrum efficacy and minimized risks associated with handling liquid biocides. Formic acid (FA) is a well-established natural acaricide used in beehives with an antiviral potential; however, its application in a liquid form is hindered by severe corrosiveness and rapid, uncontrolled evaporation. This study describes a novel formulation of FA, using a cryogel carrier for achieving a vapor-phase inactivation of viruses, thus eliminating the need for direct contact between the disinfectant and the pathogen. Firstly, a poly(N-isopropylacrylamide) (PNIPAm) cryogel was synthesized by a procedure involving cryogenic treatment, photochemical crosslinking, and freeze-drying, and then the cryogel was swollen with 65% FA or _ddH₂O as a control. After an exposure of a panel of animal and human viruses to FA, evaporated by the polymer carrier for time intervals between 15 min and 12 h, they were neutralized completely as follows: Poliovirus (PV) as a surrogate for major bee viral pathogens for 60 min by 5.1 ∆lg; Feline calicivirus (FCV) for 60 min by 5.3 ∆lg; Adenovirus 5 (AdV5) for 12 h by 4.0 ∆lg; and Influenza virus A (IAV) for 15 min by 5.1 ∆lg. Results were recorded after titration, 48–72 h incubation, cytopathic effect estimation and NR uptake assay. Our results suggest that 65% FA, when delivered via the PNIPAm cryogel matrix, acts as a powerful agent for fumigation-like disinfection. This “dry” delivery strategy offers significant practical advantages: it eliminates the need for open liquid containers, prevents spill-related hazards, and provides an alternative for controlled, long-term release of active vapors. Full article

Although ombitasvir/paritaprevir/ritonavir plus dasabuvir (OPrD) therapy is highly effective for chronic hepatitis C (CHC), clinicians frequently encounter transient hyperbilirubinemia, which can be misidentified as hepatotoxicity. This study investigated the role of SLCO1B1 (OATP1B1) and SLCO1B3 (OATP1B3) genetic polymorphisms in predicting bilirubin spikes and distinguishing transporter-mediated interference from hepatocellular injury. In this prospective study of 65 patients with HCV genotype 1, genotyping for OATP1B1 (c.388A>G, c.521T>C) and OATP1B3 (c.334T>G, c.699G>A) was performed using PCR-RFLP and capillary electrophoresis (QIAxcel Advanced System). Clinical and biochemical parameters were monitored over a 12-week treatment period. Hyperbilirubinemia (total bilirubin >1.1 mg/dL) developed in 18.5% of the cohort, typically within the first month. A distinct ‘AST-dominant’ biochemical signature, elevated bilirubin and AST paired with stable ALT, was identified, suggesting transporter-specific interference rather than hepatocyte damage. Statistical analysis pinpointed the OATP1B3 c.699G>A (rs7311358) variant as the sole genetic driver (p = 0.007). Carriers of the c.699G>A allele faced a 6.3-fold higher risk of developing hyperbilirubinemia (OR: 6.30, 95% CI: 1.48–26.80, p = 0.032), while no significant associations were found for OATP1B1 variants. We conclude that OATP1B3 c.699G>A is a potent predictor of OPrD-induced hyperbilirubinemia. Identifying this genotype pre-treatment allows clinicians to anticipate transient, benign bilirubin elevations and prevent unnecessary drug discontinuation, thereby mitigating therapeutic inertia and ensuring treatment continuity for CHC patients. Full article

Background: Hepatitis C viral infection (HCV) has historically been a leading indication for liver transplantation (LTx), primarily due to its progression to cirrhosis and hepatocellular carcinoma (HCC). However, the advent of direct-acting antiviral agents (DAAs) over a decade ago has revolutionized HCV treatment, achieving sustained virologic response (SVR) in over 90% of patients and potentially altering LTx indications. Aim: To investigate the impact of DAAs on HCV-related indications, with or without HCC, and model future trends in LTx indications. Methods: We retrospectively reviewed 1504 liver transplants performed between 2000 and 2024 at a single center. Patients were categorized into three cohorts: HCV-only, HCC-only, and HCC with HCV co-infection (HCC/HCV). Relative transplant volumes by-year, post-operative outcomes, and HCC recurrence rates were analyzed across pre- and post-DAA eras. ARIMA modeling was employed to project trends in transplant indications through the year 2030. Results: The proportion of transplants for HCV alone declined by 82.3% from 2015 to 2020, while HCC/HCV transplants decreased by 68.8%. Conversely, the total number of transplants for HCC alone increased during this period, with a modest proportional decrease of 8.3% from 2015 to 2020. ARIMA modeling suggests that by 2030, LTxs for HCV alone may be nearly eliminated. The projected proportion of transplants conducted for HCC alone remains the highest of all three study indications at 4.3%. Conclusions: DAAs have reduced LTx due to HCV. By 2030, LTx for HCV-related cirrhosis, particularly without HCC, may be obviated. This underscores the need to reevaluate allocation for emerging oncologic indications. Full article

The immunosuppressive nature of porcine reproductive and respiratory syndrome virus (PRRSV) remains the central obstacle to its effective control. Conventional microRNA (miRNA)-based antiviral approaches are limited by their modest potency and the high risk of viral escape. Here, we rationally designed an engineered miRNA carrying a 5′-triphosphate (5′-PPP) terminus that integrates RIG-I-driven innate immune activation and sequence-specific gene silencing within a single molecule. In vitro-transcribed 5′-PPP miRNAs are efficiently recognized by the pattern-recognition receptor RIG-I, triggering a robust type I interferon response that counteracts PRRSV-induced immunosuppression. In MARC-145 cells, one such construct, 5′-PPP BZL-sRNA-20, potently inhibited PRRSV replication through the synergistic action of immune activation and gene silencing. However, in porcine alveolar macrophages (PAMs)—the natural host cells for PRRSV—the antiviral effect depended primarily on 5′-PPP-induced interferon responses, with the targeting sequence providing limited or context-dependent benefits. Dual-luciferase assays confirmed that the gene-silencing activity depends on 5′-PPP modification, which enhances the stability of BZL-sRNA-20. This bifunctional strategy establishes an “immune activation plus targeting” paradigm by simultaneously acting as a RIG-I ligand that triggers broad antiviral responses and specifically cleaves viral RNA via direct base-pairing to conserved regions of the PRRSV genome. These findings reveal the potential of engineered 5′-PPP miRNAs as immunomodulatory antiviral agents, while highlighting that the contribution of RNAi targeting varies depending on the cellular context. Full article

Direct-acting antiviral therapies can cure most people with hepatitis C virus (HCV) infection with little need for testing or monitoring. A major challenge to eliminating HCV is ensuring patients complete all steps of care, including confirmation of cure. We assessed the concordance of sustained virologic response (SVR) at 4 weeks (SVR4) and 12 weeks (SVR12) post-treatment to evaluate the viability of SVR4 as a predictor of cure in patients treated with sofosbuvir (SOF)/velpatasvir (VEL). We conducted a retrospective analysis of patients from the Phase 3 ASTRAL-1, -2, and -3 programs and a historical cohort from the Louisiana Department of Health Sexually Transmitted Infection (STI)/HIV/Hepatitis Program claims database. Concordance analyses were performed for patients with both SVR4 and SVR12 data. The concordance analysis in the ASTRAL studies included 1015 patients; 1005 and 1002 achieved SVR4 and SVR12, respectively. Among SVR4 achievers, 3 failed to maintain SVR12, while all (10/10) patients who did not achieve SVR4 also failed SVR12. In the real-world cohort, 479/509 (94%) patients achieved SVR4 and 485/509 (95%) achieved SVR12. Of those with SVR4, 7 failed SVR12; 17 of 30 patients who did not achieve SVR4 also failed SVR12. High concordance between SVR4 and SVR12 was observed in both ASTRAL and the real-world dataset, supporting the use of SVR4 as a predictor of long-term SVR in patients with HCV infection treated with SOF/VEL. Streamlining cure confirmation by shifting SVR determination from week 12 to week 4 post-treatment may reduce patient loss to follow-up. Full article

Hepatitis C virus (HCV) chronically infects over 50 million people worldwide and poses a significant risk to global health. The HCV NS3/4A complex, a bifunctional enzyme comprising a protease and a helicase domain, is indispensable for viral replication and immune evasion, making it a pivotal target for direct-acting antiviral agents (DAAs). Here, we summarize its structural features, functional mechanisms, and implications in drug design and protein engineering (e.g., nanopore sequencing applications). The NS3 protease domain is activated by the NS4A cofactor, which mediates viral polyprotein processing and relies on a zinc-binding site for structural stability. The C-terminal helicase domain catalyzes ATP-dependent 3′→5′ unwinding, and allosteric crosstalk between the protease and helicase domains dynamically modulates the enzymatic activity, balancing unwinding velocity and processivity. Beyond supporting viral replication, NS3/4A cleaves MAVS to abolish RIG-I/MDA5 signaling but spares TRIF, leaving TLR3-mediated immunity intact; it also modulates host lipid and iron metabolism, contributing to HCV pathogenesis. Notably, structural and functional studies of NS3/4A lay a solid theoretical foundation for developing novel therapeutic strategies. Currently, DAAs targeting NS3/4A have achieved high sustained virologic response rates; however, resistance-associated substitutions remain a major clinical challenge, particularly in genotype 3 infections. Emerging therapeutic strategies targeting NS3/4A include allosteric inhibition and proteolysis-targeting chimeras (PROTACs)-mediated degradation. Full article

Coxsackievirus A16 (CVA16), a major etiological agent of hand, foot, and mouth disease, is increasingly contributing to neurological complications, with no vaccines or virus-specific antivirals currently available. To identify CVA16-restricting host factors, we investigated the role of the interferon-stimulated gene shiftless (SHFL), previously implicated in the control of other RNA viruses. Using CRISPR–Cas 9, we generated SHFL knockout rhabdomyosarcoma cells and assessed viral replication, cytopathic effects, and replication stage dynamics. We evaluated disease progression and tissue injury in neonatal mice infected with a mouse-adapted CVA16 strain. SHFL expression was strongly induced during CVA16 infection and was inducible by exogenous interferon-β treatment, and its loss markedly increased infectious virus production, accelerated early replication, and exerted severe cytopathic effects. In vivo, SHFL deficiency led to rapid weight loss, pronounced neurological signs, increased viral burden across multiple tissues, and uniform mortality, together with high viral loads and extensive pathological damage in the central nervous system, lungs, and skeletal muscle. Transcriptomic analyses revealed SHFL-dependent modulation of adhesion- and mitogen-activated protein kinase-related pathways. Overall, our results suggest SHFL as a key determinant of host resistance to CVA16, acting mainly at the post-transcriptional stage to limit viral spread and tissue injury, and highlight SHFL-linked pathways as promising host-directed antiviral targets. Full article

Significant advances in coronavirus immunoprophylaxis have enabled the control of the SARS-CoV-2 pandemic. However, the continued emergence of SARS-CoV-2 variants with immune escape potential highlights the need for effective direct-acting antivirals targeting conserved viral enzymes. The SARS-CoV-2 main protease (M^pro) remains one of the most promising antiviral drug targets due to its essential role in viral replication and the high conservation of its active site across coronavirus variants. Building upon the established GC373 scaffold, we designed, synthesized, and biochemically evaluated two novel GC373-like peptidomimetic inhibitors incorporated modified glutamine-mimic residues. These analogs were designed to enhance solubility and metabolic resilience while retaining key recognition features within the M^pro active site. Both compounds demonstrated micromolar inhibitory activity in enzymatic assays, supported by molecular docking and MM-PBSA analyses consistent with stable binding. The proposed inhibitors represent viable scaffolds for further optimization of electrophilic warheads and S1/S2 residue interactions. These findings contribute to the rational design of next-generation M^pro inhibitors and align with ongoing efforts to expand the chemical space of SARS-CoV-2 antiviral agents. Full article

Background & Aims: Hepatitis C virus (HCV) infection remains one of the most significant and lethal infectious diseases worldwide. Since the approval of the first direct-acting antiviral agent in 2013, the therapeutic landscape has changed dramatically, with SVR rates exceeding 95%. The WHO set the ambitious goal of achieving global HCV elimination in 2030. High-risk populations remain among the most challenging yet essential groups to treat in order to reach this objective. The aim of this study is to describe two distinct approaches targeting high-risk populations to advance HCV elimination. Methods: An observational study was conducted from April 2017 to August 2025, including patients evaluated and treated at Porto’s correctional facility and Porto’s addiction centers. All patients received DAA therapy, and the primary outcome was sustained virological response at 12 weeks post-treatment. Results: A total of 124 patients from the prison setting were included. Their mean age was 43.0 ± 8.4 years, and all were males. Treatment with DAA resulted in an SVR of 99.2%. In addition, 43 patients from the addiction centers were included, with a mean age of 54.9 ± 5.9 years, and the majority were males (86%). These patients achieved an SVR 12 of 97.7%. Conclusions: In two distinct and difficult-to-reach high-risk populations, we demonstrated that a tailored approach involving on-site evaluation and treatment of HCV infection is highly effective and may be crucial to achieving HCV elimination. Full article

SARS-CoV-2, the causative agent of COVID-19, has led to over seven million deaths worldwide prior to May 2025. Despite widespread vaccination programs, COVID-19 remains a persistent global health challenge, underscoring the urgent need for new therapeutic approaches. Orientin is a flavonoid with reported antiviral activity, though its potential against SARS-CoV-2 remains poorly explored. This study aimed to investigate whether Orientin interacts with the viral Spike protein and impacts viral replication. Molecular docking simulations using DockThor were employed to predict the binding affinity between Orientin and the receptor-binding domain (RBD) of the Spike protein. Fluorescence spectroscopy assays were performed to assess direct interactions between Orientin and the trimeric form of the Spike protein. Additionally, cytotoxicity and viral replication assays were carried out in Vero cells to evaluate Orientin’s antiviral effects. Docking results indicated that Orientin likely binds to key RBD residues involved in ACE2 receptor recognition. Spectroscopic analyses showed a decrease in intrinsic tryptophan fluorescence, suggesting direct interaction. Orientin demonstrated no cytotoxicity in Vero cells and exhibited moderate inhibition of viral replication. These findings suggest that Orientin interacts with critical regions of the Spike protein and may act as a moderate in vitro inhibitor of SARS-CoV-2, warranting further investigation into its therapeutic potential. Full article

Conventional ultrasound (US) has long been central to hepatocellular carcinoma (HCC) surveillance in cirrhotic patients, due to its low cost, wide availability, non-invasiveness, and adequate sensitivity for detecting small nodules. However, its specificity in distinguishing HCC from other lesions is limited. Contrast-enhanced ultrasound (CEUS) has significantly improved the characterization of nodules first identified on conventional US. Yet, when CEUS is performed using sulfur hexafluoride (SonoVue)—the only contrast agent available in Western countries—assessment remains restricted to a single nodule per examination, and enhanced CT or MRI is still required for full characterization and staging. In clinical settings, such as hepatology, internal medicine, infectious diseases, and surgery, CEUS offers the advantage of immediate availability, enabling rapid characterization of suspicious nodules in cirrhotic livers and facilitating timely therapeutic decisions. Although the introduction of direct-acting antivirals (DAAs) has substantially reduced HCV-related HCC, HCC incidence is increasingly driven by metabolic dysfunction-associated steatohepatitis (MASH). Evidence on surveillance strategies for MASH patients remains limited, and current EASL guidelines recommend monitoring only patients with >F2 fibrosis. Additionally, the effectiveness of US in obese or diabetic/obese populations is under ongoing investigation; abbreviated non-contrast MRI has been proposed as an alternative surveillance tool, but its adoption would entail significant economic implications for healthcare systems. HCC arising from MASH—sometimes even without cirrhosis—exhibits different sonographic and pathological features. Instead of small, hypoechoic nodules, typically seen in HCV-related cirrhosis, clinicians increasingly encounter larger or multiple lesions, often accompanied by macrovascular invasion, limiting access to curative treatments. Furthermore, typical CEUS LI-RADS patterns are less frequently observed. This review summarizes the evolving US findings in the era of MASH-related HCC and underscores the continued importance of US as the primary imaging tool in routine clinical practice. Full article

People who use crack cocaine (PWUCC) constitute a key population due to vulnerability and marginalization, especially in a socio-ecologically diverse, relatively isolated region with limited public health infrastructure. This study aimed to perform a genetic characterization of circulating HCV among PWUCC in the municipality of Bragança, situated on the Brazilian Amazon coast, identifying viral genotypes, subtypes, resistance-associated substitutions (RAS)—naturally occurring mutations in the viral genome that can reduce the efficacy of direct-acting antiviral (DAA) agents—and predictions of phenotypic resistance. Methods: Between 2016 and 2018, biological samples and epidemiological data were obtained from 165 PWUCC. Viral detection was performed using RT-PCR, while genotyping, subtyping, and RAS profiling were conducted through nucleotide sequencing and fragment analysis. Results: In 165 PWUCC, 22 (13.3%) tested positive for HCV RNA. Most of them had not had access to public health services (91.5%), and more than half (57.0%) reported living in unstable housing conditions. HCV subtypes 1a (27.3%), 1b (40.9%), and 3a (31.8%) were detected. Evidence of resistance associated with DAAs, such as daclatasvir and dasabuvir, was detected in five PWUCC with HCV (22.7%). Conclusions: The high prevalence of HCV infection, predominantly subtype 1b, and significant levels of resistance are very concerning. This demonstrates the urgent need for targeted public health interventions to expand access to testing, treatment, and effective antiviral therapy in this vulnerable population of the Brazilian Amazon. Full article

Background/Objectives: Coxsackievirus B3 (CVB3), a neurotropic enterovirus, is a major causative agent of viral encephalitis and myocarditis, yet no protective vaccine or effective antiviral therapy is currently available. Autophagy plays a dual role in viral infections, acting as both an antiviral defense and a process that can be exploited by certain viruses. Although CVB3 has been proposed to utilize autophagosomes as replication platforms, the underlying mechanisms remain controversial. Methods: In this study, we investigated the relationship between CVB3 replication and autophagosome formation under starvation-induced conditions and in ATG5 knockout cells. Results: While nutrient deprivation robustly induced autophagy, CVB3 infection did not trigger autophagosome formation. Moreover, viral replication proceeded efficiently in ATG5-deficient cells lacking autophagosomes. Pharmacological modulation of autophagy using rapamycin, a potent autophagy inducer, did not alter intracellular viral titers or protein expression, although extracellular viral release was modestly reduced. These results indicate that CVB3 replication occurs independently of autophagosome formation, suggesting that pharmacological targeting of autophagy provides limited therapeutic benefit. Conclusions: This study refines our understanding of autophagy as an antiviral target and highlights the need to identify alternative host-directed pathways for antiviral drug development. Full article