Daclatasvir as a hepatitis C infection treatment option: an up-to-date evaluation

INTRODUCTION

Globally, it is estimated that 290,000 patients infected with hepatitis C virus (HCV) died from hepatitis C consequences, including cirrhosis and hepatocellular carcinoma in 2019. Although daclatasvir (DCV), combined with sofosbuvir (SOF), is effective in HCV patients, the new pan-genotypic combinations are considered by many as more cost-effective and successful in eradicating HCV infection.

AREAS COVERED

This review discusses the safety, efficacy, and cost-effectiveness of DCV as an HCV treatment option based on real-world studies and pharmacoeconomic evaluations.

EXPERT OPINION

Real-life studies suggest that SOF/DCV has acceptable sustained virological response and can be used successfully to manage HCV. Nonetheless, the use of SOF/DCV is limited by the longer treatment duration in genotype (GT)-3 patients and the need for ribavirin (RBV) in treatment-experienced patients which increases the likelihood of adverse effects. DCV is likely to remain as a therapeutic option for the management of GT-1, GT-2, and GT-4 patients in resource limited settings, while GT-3 patients are more likely to benefit from RBV-free direct-acting antiviral combinations such as SOF/velpatasvir for 12 weeks or glecaprevir/pibrentasvir for 8 weeks. The introduction of generics for these new pan-genotypic drugs would likely eliminate the need for SOF/DCV in the near future.

Age, tissue, genotype and virus infection regulate Wolbachia levels in Drosophila

The bacterial symbiont Wolbachia can protect insects against viral pathogens, and the varying levels of antiviral protection are correlated with the endosymbiont load within the insects. To understand why Wolbachia strains differ in their antiviral effects, we investigated the factors controlling Wolbachia density in five closely related strains in their natural Drosophila hosts. We found that Wolbachia density varied greatly across different tissues and between flies of different ages, and these effects depended on the host-symbiont association. Some endosymbionts maintained largely stable densities as flies aged while others increased, and these effects in turn depended on the tissue being examined. Measuring Wolbachia rRNA levels in response to viral infection, we found that viral infection itself also altered Wolbachia levels, with Flock House virus causing substantial reductions in symbiont loads late in the infection. This effect, however, was virus-specific as Drosophila C virus had little impact on Wolbachia in all of the five host systems. Because viruses have strong tissue tropisms and antiviral protection is thought to be cell-autonomous, these effects are likely to affect the virus-blocking phenomenon. However, we were unable to find any evidence of a correlation between Wolbachia and viral titres within the same tissues. We conclude that Wolbachia levels within flies are regulated in a complex host-symbiont-virus-dependent manner and this trinity is likely to influence the antiviral effects of Wolbachia.

Correlation between IL28B/TLR4 genetic variants and HCC development with/without DAAs treatment in chronic HCV patients

In Egypt, Sofosbuvir (SOF) in combination with Dataclasvir (DCV) is the broadly used DAAs with excellent therapeutic profile. This study is designed to explore the relation between IL28B/TLR4 genetic variants and each of the followings; HCC development post SOF/DCV treatment, progression to HCC in naïve patients and SOF/DCV therapy outcome. A total of 493 blood samples were collected (controls (n = 70); HCV patients treated with SOF/DCV (n = 252) of whom 65 patients developed HCC, 187 patients didn't develop HCC (125 responders, 62 relapsers); naïve HCV patients (n = 171) had early (n = 48), late liver fibrosis (n = 21) and HCC (n = 102)). Both SNPs were genotyped using a TaqMan 5′ allelic discrimination assay. At IL28B rs12979860 SNP, the C allele was significantly correlating with the response rate more than T allele (OR 1.9, 95% CI 1.29–2.9, p = 0.004), while at TLR4 rs4986791 SNP, no association was found (OR 6.5, 95% 0.57–75.28, p = 0.09). Both SNPs couldn't detect the probability for HCC emergence after treatment. In naïve patients, the protective alleles were detected in their lowest frequency in HCC patients (p = 0.1, for rs12979860 and, p = 0.001 for rs4986791). SOF/DCV combination improved SVR rates in HCV genotype 4a infected patients regardless of IL28B genotype, with the best rates in those lacking the T allele.

Efficacy and safety of 12 weeks of daclatasvir, asunaprevir plus ribavirin for HCV genotype-1b infection without NS5A resistance-associated substitutions

BACKGROUND/PURPOSE

Treatment with daclatasvir plus asunaprevir (DCV + ASV) for 24 weeks provided a sustained virologic response (SVR) rate of over 90% in hepatitis C virus genotype 1b (HCV-1b) infected patients without non-structural 5A (NS5A) resistance-associated substitutions (RASs) at the L31 and Y93 sites. In this study, we investigated whether adding ribavirin to the DCV + ASV combination could shorten the original treatment regimen to 12 weeks without compromising the treatment efficacy for HCV-1b patients without NS5A RASs.

METHODS

In the prospective, open-label, single-arm, nationwide multi-center phase III study, a total of 70 interferon-naïve or interferon-experienced HCV-1b patients without baseline L31/Y93 RASs received daclatasvir (60 mg/day) and asunaprevir (100 mg twice daily) plus weight-based ribavirin (1000-1200 mg/day) for 12 weeks, with a 12-week post-treatment follow-up. The primary end-point was the rate of undetectable HCV RNA 12 weeks post-treatment (SVR12).

RESULTS

The SVR12 rate was 97.1% (68/70) and 100% (68/68) in the full-analysis-set and the per-protocol population, respectively. None of the 68 patients who completed the 12-week treatment experienced relapse during post-treatment follow-up. Two patients withdrew from the study at treatment days 21 and 34 due to anorexia and fatigue, which were considered ribavirin-related and resolved post medication cessation. A total of 4 serious adverse events were reported and considered treatment-unrelated. No deaths or grade 4 adverse events requiring hospitalization was observed throughout the study.

CONCLUSION

Truncated regimen of DCV + ASV plus ribavirin for 12 weeks was highly effective and safe in HCV-1b patients without NS5A L31/Y93 RAS.

Calcium-dependent activator protein for secretion 2 (CADPS2) deficiency causes abnormal synapse development in hippocampal mossy fiber terminals

Hippocampal mossy fibers (MFs) project from dentate gyrus granule cells onto the CA2-CA3 region. MF-mediated synaptic transmission plays an important role in hippocampal learning and memory. However, the molecular mechanisms underlying MF synaptic development and subsequent functional organization are not fully understood. We previously reported that calcium-dependent activator protein for secretion 2 (CADPS2, also known as CAPS2) regulates the secretion of dense-core vesicles (DCVs). Because CADPS2 is strongly expressed in MF terminals, we hypothesized that CADPS2 regulates the development and functional organization of MF synapses by controlling the secretion of DCVs and their contents. To test this, we compared the synaptic microstructures of hippocampal MF terminals in Cadps2 knockout (KO) mice and wild-type (WT) mice by electron microscopy (EM). On postnatal day 15 (P15), KO mice exhibited morphological abnormalities in MF boutons, including smaller bouton size, a larger number of DCVs and a smaller number of post-synaptic densities (PSDs), compared with WT mice. In adults (P56), MF boutons were larger in KO mice. Synaptic vesicles (SVs) were increased but with a lower density compared with the WT. Furthermore, the number of SVs was decreased near the active zone. Moreover, MF-innervated CA3 postsynapses in KO mice displayed aberrant structures at the postsynaptic density (PSD), with an increased number of PSDs (likely because of a larger number of perforated PSDs), compared with WT mice. Taken together, our findings suggest that CADPS2 plays a critical role in MF synaptic development and functional organization.

Analysis of virus susceptibility in the invasive insect pest Drosophila suzukii

The invasive insect pest Drosophila suzukii infests ripening fruits and causes massive agricultural damage in North America and Europe (Cini et al., 2012). Environmentally sustainable strategies are urgently needed to control the spread of this species, and entomopathogenic viruses offer one potential solution for global crop protection. Here we report the status of intrinsic and extrinsic factors that influence the susceptibility of D. suzukii to three model insect viruses: Drosophila C virus, Cricket paralysis virus and Flock house virus. Our work provides the basis for further studies using D. suzukii as a host system to develop viruses as biological control agents.

Complex Coding and Regulatory Polymorphisms in a Restriction Factor Determine the Susceptibility of Drosophila to Viral Infection

It is common to find that major-effect genes are an important cause of variation in susceptibility to infection. Here we have characterized natural variation in a gene called pastrel that explains over half of the genetic variance in susceptibility to the Drosophila C virus (DCV) in populations of Drosophila melanogaster We found extensive allelic heterogeneity, with a sample of seven alleles of pastrel from around the world conferring four phenotypically distinct levels of resistance. By modifying candidate SNPs in transgenic flies, we show that the largest effect is caused by an amino acid polymorphism that arose when an ancestral threonine was mutated to alanine, greatly increasing resistance to DCV. Overexpression of the ancestral, susceptible allele provides strong protection against DCV; indicating that this mutation acted to improve an existing restriction factor. The pastrel locus also contains complex structural variation and cis-regulatory polymorphisms altering gene expression. We find that higher expression of pastrel is associated with increased survival after DCV infection. To understand why this variation is maintained in populations, we investigated genetic variation surrounding the amino acid variant that is causing flies to be resistant. We found no evidence of natural selection causing either recent changes in allele frequency or geographical variation in frequency, suggesting that this is an old polymorphism that has been maintained at a stable frequency. Overall, our data demonstrate how complex genetic variation at a single locus can control susceptibility to a virulent natural pathogen.

Long-Term Follow-Up of Resistance-Associated Substitutions in Hepatitis C Virus in Patients in Which Direct Acting Antiviral-Based Therapy Failed

We evaluated the transition of dominant resistance-associated substitutions (RASs) in hepatitis C virus during long-term follow-up after the failure of DAAs (direct acting antivirals)-based therapy. RASs in non-structure (NS)3/4A, NS5A, NS5B, and deletions in NS5A from 20 patients who failed simeprevir/pegylated-interferon/ribavirin (SMV/PEG-IFN/RBV) and 25 patients who failed daclatasvir/asunaprevir (DCV/ASV) treatment were examined by direct sequencing. With respect to SMV/PEG-IFN/RBV treatment, RAS was detected at D168 in NS3/4A but not detected in NS5A and NS5B at treatment failure in 16 of 20 patients. During the median follow-up period of 64 weeks, the RAS at D168 became less dominant in 9 of 16 patients. Among 25 DCV/ASV failures, RASs at D168, L31, and Y93 were found in 57.1%, 72.2%, and 76.9%, respectively. NS5A deletions were detected in 3 of 10 patients treated previously with SMV/PEG-IFN/RBV. The number of RASs in the breakthrough patients exceeded that in relapsers (mean 3.9 vs. 2.7, p < 0.05). RAS at D168 in NS3/4A became less dominant in 6 of 15 patients within 80 weeks. Y93H emerged at the time of relapse, then decreased gradually by 99% at 130 weeks post-treatment. Emerged RASs were associated with the clinical course of treatment and could not be detected during longer follow-up.

Infection avoidance behavior: Viral exposure reduces the motivation to forage in female Drosophila melanogaster

Infection avoidance behaviors are the first line of defense against pathogenic encounters. Behavioral plasticity in response to internal or external cues of infection can therefore generate potentially significant heterogeneity in infection. We tested whether Drosophila melanogaster exhibits infection avoidance behavior, and whether this behavior is modified by prior exposure to Drosophila C Virus (DCV) and by the risk of DCV encounter. We examined 2 measures of infection avoidance: (1) the motivation to seek out food sources in the presence of an infection risk and (2) the preference to land on a clean food source over a potentially infectious source. While we found no evidence for preference of clean food sources over potentially infectious ones, previously exposed female flies showed lower motivation to pick a food source when presented with a risk of encountering DCV. We discuss the relevance of behavioral plasticity during foraging for host fitness and pathogen spread.

Sex-specific behavioural symptoms of viral gut infection and Wolbachia in Drosophila melanogaster

All organisms are infected with a range of symbionts spanning the spectrum of beneficial mutualists to detrimental parasites. The fruit fly Drosophila melanogaster is a good example, as both endosymbiotic Wolbachia, and pathogenic Drosophila C Virus (DCV) commonly infect it. While the pathophysiology and immune responses against both symbionts are the focus of intense study, the behavioural effects of these infections have received less attention. Here we report sex-specific behavioural responses to these infections in D. melanogaster. DCV infection caused increased sleep in female flies, but had no detectable effect in male flies. The presence of Wolbachia did not reduce this behavioural response to viral infection. We also found evidence for a sex-specific cost of Wolbachia, as male flies infected with the endosymbiont became more lethargic when awake. We discuss these behavioural symptoms as potentially adaptive sickness behaviours.

DIP1 plays an antiviral role against DCV infection in Drosophila melanogaster

Disconnected Interacting Protein 1 (DIP1) is a dsRNA-binding protein that participates in a wide range of cellular processes. Whether DIP1 is involved in innate immunity remains unclear. Here, DIP1 was found to play an antiviral role in S2 cells. Its antiviral action is specific for DCV infection and not for DXV infection. dip1 mutant flies are hypersensitive to DCV infection. The increased mortality in dip1 mutant flies is associated with the accumulation of DCV positive-stranded RNAs in vivo. This study demonstrated that dip1 is a novel antiviral gene that restricts DCV replication in vitro and in vivo.

Involvement of Ran in the regulation of phagocytosis against virus infection in S2 cells

Phagocytosis plays important roles in innate and adaptive immunity in animals. Some small G proteins are found to be related to phagocytosis. However, the Ran GTPase has not been intensively characterized in immunity. In this paper, the sequence analysis showed that the Ran was highly conserved in animals, suggesting that its function was preserved during animal evolution. The results showed that Ran was upregulated in S2 cells in response to DCV infection. It was further revealed that the antiviral phagocytosis could be mediated by Ran in S2 cells. By comparison with the early marker and late marker of phagosomes, the results showed that the Ran protein played an essential role at the early stage of phagocytosis or throughout the entire phagocytic process. Therefore our findings enlarged our limited knowledge about the phagocytosis regulation by small G proteins concerning to the nucleus.

[Characterization of lipid profile in primary health care users in Portugal]

AIM

To characterize the distribution of total cholesterol (TC), LDL cholesterol (LDL-C), HDL cholesterol (HDL-C) and triglycerides in primary health care users.

METHODS

We performed a cross-sectional study in a primary care setting, involving 719 general practitioners based on stratified distribution proportional to the population density of each region of Portugal. The first two adult patients scheduled for an appointment on a given day were invited to participate. A questionnaire was applied to assess sociodemographic, clinical and laboratory data including lipid profile.

RESULTS

The study included 16 856 individuals (mean age 58.1±15.1 years; 61.6% women). Data on TC, LDL-C, HDL-C and triglycerides were available for 95.9% (n=16 159), 59.1% (n=9956), 95.4% (n=16 074) and 97.9% (n=16 494) of the population, respectively. Hypercholesterolemia (TC ≥200 mg/dl) was detected in 47%, and 38.4% had high levels of LDL-C (≥130 mg/dl). Hypertriglyceridemia (≥200 mg/dl) and low HDL-C (<40 mg/dl) were less prevalent, affecting roughly 13% of the population. Dyslipidemia was more common in middle-aged men and in post-menopausal women. Of the population aged over 40, 54.1% met eligibility criteria for lipid-lowering therapy and 44.7% were medicated with statins, but only 16.0% of these had TC ≤175 mg/dl.

CONCLUSIONS

Dyslipidemia is highly prevalent in primary health care users in Portugal. It is particularly common in middle-aged men and post-menopausal women, who should be considered target groups for preventive public health measures.

Insect antiviral innate immunity: pathways, effectors, and connections

Insects are infected by a wide array of viruses some of which are insect restricted and pathogenic, and some of which are transmitted by biting insects to vertebrates. The medical and economic importance of these viruses heightens the need to understand the interaction between the infecting pathogen and the insect immune system in order to develop transmission interventions. The interaction of the virus with the insect host innate immune system plays a critical role in the outcome of infection. The major mechanism of antiviral defense is the small, interfering RNA pathway that responds through the detection of virus-derived double-stranded RNA to suppress virus replication. However, other innate antimicrobial pathways such as Imd, Toll, and Jak-STAT and the autophagy pathway have also been shown to play important roles in antiviral immunity. In this review, we provide an overview of the current understanding of the main insect antiviral pathways and examine recent findings that further our understanding of the roles of these pathways in facilitating a systemic and specific response to infecting viruses.

Association between cardiovascular disease and socioeconomic level in Portugal

INTRODUCTION

Cardiovascular disease is the leading cause of morbidity, mortality and disability in Portugal. Socioeconomic level is known to influence health status but there is scant evidence on socioeconomic inequalities in cardiovascular disease in Portugal.

AIM

To analyze the distribution of cardiovascular disease in the Portuguese population according to socioeconomic status.

METHODS

We conducted a cross-sectional study using data from the fourth National Health Survey on a representative sample of the Portuguese population. Socioeconomic inequalities in cardiovascular disease, risk factors and number of medical visits were analyzed using odds ratios according to socioeconomic status (household equivalent income) in the adult population (35-74 years). Comparisons focused on the top and bottom 50% and 10% of household income distribution.

RESULTS

Of the 21 807 individuals included, 53.3% were female, and mean age was 54 ± 11 years. Cardiovascular disease, stroke, ischemic heart disease, hypertension, diabetes, obesity and physical inactivity were associated with lower socioeconomic status, while smoking was associated with higher status; number of medical visits and psychological distress showed no association. When present, inequality was greater at the extremes of income distribution.

CONCLUSIONS

The results reveal an association between morbidity, lifestyle and socioeconomic status. They also suggest that besides improved access to effective medical intervention, there is a need for a comprehensive strategy for health promotion and disease prevention that takes account of individual, cultural and socioeconomic characteristics.

Sortilin and the risk of cardiovascular disease

Plasma low-density lipoprotein cholesterol (LDL-C) levels are a key determinant of the risk of cardiovascular disease, which is why many studies have attempted to elucidate the pathways that regulate its metabolism. Novel latest-generation sequencing techniques have identified a strong association between the 1p13 locus and the risk of cardiovascular disease caused by changes in plasma LDL-C levels. As expected for a complex phenotype, the effects of variation in this locus are only moderate. Even so, knowledge of the association is of major importance, since it has unveiled a new metabolic pathway regulating plasma cholesterol levels. Crucial to this discovery was the work of three independent teams seeking to clarify the biological basis of this association, who succeeded in proving that SORT1, encoding sortilin, was the gene in the 1p13 locus involved in LDL metabolism. SORT1 was the first gene identified as determining plasma LDL levels to be mechanistically evaluated and, although the three teams used different, though appropriate, experimental methods, their results were in some ways contradictory. Here we review all the experiments that led to the identification of the new pathway connecting sortilin with plasma LDL levels and risk of myocardial infarction. The regulatory mechanism underlying this association remains unclear, but its discovery has paved the way for considering previously unsuspected therapeutic targets and approaches.

Physiological and metabolic consequences of viral infection in Drosophila melanogaster

An extensively used model system for investigating anti-pathogen defence and innate immunity involves Drosophila C virus (DCV) and Drosophila melanogaster. While there has been a significant effort to understand infection consequences at molecular and genetic levels, an understanding of fundamental higher-level physiology of this system is lacking. Here, we investigate the metabolic rate, locomotory activity, dry mass and water content of adult male flies injected with DCV, measured over the 4 days prior to virus-induced mortality. DCV infection resulted in multiple pathologies, notably the depression of metabolic rate beginning 2 days post-infection as a response to physiological stress. Even in this depressed metabolic state, infected flies did not decrease their activity until 1 day prior to mortality, which further suggests that cellular processes and synthesis are disrupted because of viral infection. Growth rate was also reduced, indicating that energy partitioning is altered as infection progresses. Microbial infection in insects typically results in an increase in excretion; however, water appeared to be retained in DCV-infected flies. We hypothesise that this is due to a fluid intake-output imbalance due to disrupted transport signalling and a reduced rate of metabolic processing. Furthermore, infected flies had a reduced rate of respiration as a consequence of metabolic depression, which minimised water loss, and the excess mass as a result of water retention is concurrent with impaired locomotory ability. These findings contribute to developing a mechanistic understanding of how pathologies accumulate and lead to mortality in infected flies.