Neuraminidase Inhibitors Research Articles

Novel modelling approaches to predict the role of antivirals in reducing influenza transmission.

To aid understanding of the effect of antiviral treatment on population-level influenza transmission, we used a novel pharmacokinetic-viral kinetic transmission model to test the correlation between nasal viral load and infectiousness, and to evaluate the impact that timing of treatment with the antivirals oseltamivir or baloxavir has on influenza transmission. The model was run under three candidate profiles whereby infectiousness was assumed to be proportional to viral titer on a natural-scale, log-scale, or dose-response model. Viral kinetic profiles in the presence and absence of antiviral treatment were compared for each individual (N = 1000 simulated individuals); subsequently, viral transmission mitigation was calculated. The predicted transmission mitigation was greater with earlier administration of antiviral treatment, and with baloxavir versus oseltamivir. When treatment was initiated 12-24 hours post symptom onset, the predicted transmission mitigation was 39.9-56.4% for baloxavir and 26.6-38.3% for oseltamivir depending on the infectiousness profile. When treatment was initiated 36-48 hours post symptom onset, the predicted transmission mitigation decreased to 0.8-28.3% for baloxavir and 0.8-19.9% for oseltamivir. Model estimates were compared with clinical data from the BLOCKSTONE post-exposure prophylaxis study, which indicated the log-scale model for infectiousness best fit the observed data and that baloxavir affords greater reductions in secondary case rates compared with neuraminidase inhibitors. These findings suggest a role for baloxavir and oseltamivir in reducing influenza transmission when treatment is initiated within 48 hours of symptom onset in the index patient.

Lessons from resistance analysis in clinical trials of IV zanamivir

Influenza infection causes substantial morbidity and mortality during seasonal epidemics and pandemics. Antivirals, including neuraminidase inhibitors, play an important role in the treatment of severely ill patients infected with influenza. Resistance is a key factor that can affect the efficacy of neuraminidase inhibitors (NAIs). It is a recommendation by regulatory authorities to monitor for resistance during the development of anti-influenza medications. An additional requirement by regulators is to examine amino acid sequences for minority species harbouring resistance substitutions. In a Phase III study of intravenous (IV) zanamivir respiratory samples were analysed for the presence of resistant quasi species using Next Generation Sequencing (NGS). In this study ten resistance substitutions, two of which were treatment emergent, were detected by NGS that otherwise would not have been detectable by Sanger sequencing. None of the substitutions were present at any other timepoints analysed. The effect these mutations have on clinical response is difficult to characterize; in fact, all patients from which these variants were isolated had a successful clinical outcome and the effect on clinical response was therefore likely minimal. Although NGS is becoming a routine method for nucleic acid sequencing and will detect substitutions previously undetected by Sanger sequencing, the value of this technique in identifying minority species with resistance substitutions that are clinically meaningful remains to be demonstrated, particularly with acute infections such as influenza.

Research Progress on the Mechanism of Action of Maxing Shigan Decoction in the Treatment of Viral Pneumonia

Viral pneumonia refers to the lung inflammation caused by a viral infection, the main causative agent is Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2), Influenza virus (Flu), parainfluenza virus (HPIV), adenovirus (Adv), respiratory syncytial virus (RSV), etc., Its main symptoms are fever, cough, shortness of breath, wheezing and wet lung rales, with changes in chest imaging (X-ray, ultrasound, CT, etc.), For the treatment of viral pneumonia, in addition to the treatment with influenza viruses that can be treated with neuraminidase inhibitors, no specific drugs for other viruses, Clinical mainly symptomatic treatment. Current studies have proved that the inflammatory cytokines IL-6, TNF-α; the stimulating molecule CD137 and the chemokine CXCL-10, and the signaling pathway NF-κB signaling pathway, TLR 4-MyD 88-TRAF-6 pathway effectively inhibit inflammatory response, promote viral clearance, and effectively treat viral pneumonia. Viral pneumonia belongs to the category of "pneumonia asthma" in traditional Chinese medicine. For its heat syndrome and demonstration, such as wind heat, phlegm heat, toxic fever and other syndrome types, it can be used as the basic prescription for addition and subtraction treatment.

Pyrrolo[2,3-e]indazole as a novel chemotype for both influenza A virus and pneumococcal neuraminidase inhibitors.

Influenza infections are often exacerbated by secondary bacterial infections, primarily caused by Streptococcus pneumoniae. Both respiratory pathogens have neuraminidases that support infection. Therefore, we hypothesized that dual inhibitors of viral and bacterial neuraminidases might be an advantageous strategy for treating seasonal and pandemic influenza pneumonia complicated by bacterial infections. By screening our in-house chemical library, we discovered a new chemotype that may be of interest for a further campaign to find small molecules against influenza. Our exploration of the pyrrolo[2,3-e]indazole space led to the identification of two hit compounds, 6h and 12. These molecules were well-tolerated by MDCK cells and inhibited the replication of H3N2 and H1N1 influenza A virus strains. Moreover, both compounds suppress viral and pneumococcal neuraminidases indicating their dual activity. Given its antiviral activity, pyrrolo[2,3-e]indazole has been identified as a promising scaffold for the development of novel neuraminidase inhibitors that are active against influenza A virus and S. pneumoniae.

Pseudotyped Viruses for Influenza.

We have developed an influenza hemagglutinin (HA) pseudotype (PV) library encompassing all influenza A (IAV) subtypes from HA1-HA18, influenza B (IBV) subtypes (both lineages), representative influenza C (ICV), and influenza D (IDV) viruses. These influenza HA (or hemagglutinin-esterase fusion (HEF) for ICV and IDV) pseudotypes have been used in a pseudotype microneutralization assay(pMN), an optimized luciferase reporter assay, that is highly sensitive and specific for detecting neutralizing antibodies against influenza viruses. This has been an invaluable tool in detecting the humoral immune response against specific hemagglutinin or hemagglutinin-esterase fusion proteins for IAV to IDV in serum samples and for screening antibodies for their neutralizing abilities. Additionally, we have also produced influenza neuraminidase (NA) pseudotypes for IAV N1-N9 subtypes and IBV lineages. We have utilized these NA-PV as surrogate antigens in in vitro assays to assess vaccine immunogenicity. These NAPV have been employed as the source of neuraminidase enzyme activity in a pseudotype enzyme-linked lectin assay (pELLA) that is able to measure neuraminidase inhibition (NI) titers of reference antisera, monoclonal antibodies, and postvaccination sera. Here we show the production of influenza HA, HEF, and NAPV and their employment as substitutes for wild-type viruses in influenza serological and neutralization assays. We also introduce AutoPlate, an easily accessible web app that can analyze data from pMN and pELLA quickly and efficiently, plotting inhibition curves and calculating half-maximal concentration (IC50) neutralizing antibody titers. These serological techniques coupled with user-friendly analysis tools are faster, safer, inexpensive alternatives to classical influenza assays while also offering the reliability and reproducibility to advance influenza research and make it more accessible to laboratories around the world.

Vitisin B inhibits influenza A virus replication by multi-targeting neuraminidase and virus-induced oxidative stress.

The development of drug-resistant influenza and new pathogenic virus strains underscores the need for antiviral therapeutics. Currently, neuraminidase (NA) inhibitors are commonly used antiviral drugs approved by the US Food and Drug Administration (FDA) for the prevention and treatment of influenza. Here, we show that vitisin B (VB) inhibits NA activity and suppresses H1N1 viral replication in MDCK and A549 cells. Reactive oxygen species (ROS), which frequently occur during viral infection, increase virus replication by activating the NF-κB signaling pathway, downmodulating glucose-6-phosphate dehydrogenase (G6PD) expression, and decreasing the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant response activity. VB decreased virus-induced ROS generation by increasing G6PD expression and Nrf2 activity, and inhibiting NF-κB translocation to the nucleus through IKK dephosphorylation. In addition, VB reduced body weight loss, increased survival, decreased viral replication and the inflammatory response in the lungs of influenza A virus (IAV)-infected mice. Taken together, our results indicate that VB is a promising therapeutic candidate against IAV infection, complements existing drug limitations targeting viral NA. It modulated the intracellular ROS by G6PD, Nrf2 antioxidant response pathway, and NF-κB signaling pathway. These results demonstrate the feasibility of a multi-targeting drug strategy, providing new approaches for drug discovery against IAV infection.

Neuraminidase Inhibitors Resistance: The Irrational Use of Oseltamivir Can Lead to Genesis of Mutant Avian Influenza Viruses in The Field

Neuraminidase Inhibitors Resistance: The Irrational Use of Oseltamivir Can Lead to Genesis of Mutant Avian Influenza Viruses in The Field

EPSP-Spike coupling due to endogenous neuraminidase inhibition

EPSP-Spike coupling due to endogenous neuraminidase inhibition

Selenium-ruthenium complex blocks H1N1 influenza virus-induced cell damage by activating GPx1/TrxR1.

Background: Influenza A (H1N1) virus is an acute respiratory infectious disease that causes massive morbidity and mortality worldwide. As an essential trace element, selenium is widely applied in the treatment of various diseases because of its functions of enhancing immune response, antioxidant and antiviral mutation. In this study, we constructed the selenium-containing metal complex drug delivery system Ru(biim)(PhenSe)2 (RuSe), and investigated the anti-influenza virus efficacy and the potential antiviral mechanism for RuSe. Methods: The inhibitory effect of RuSe on influenza-mediated apoptosis was examined by cell count assay, cell cycle assay, Annenxin-V assay, TUNEL-DAPI assay and reactive oxygen species level determination. Virulence assay, PCR and neuraminidase inhibition assay revealed the inhibition of RuSe on influenza virus. At the level of animal experiments, two animal models were used to clarify the role of RuSe through HE staining, immunohistochemical staining, cytokine determination, selenium metabolism determination and selenium protein expression level determination. Results: The results of this study confirm that RuSe enhances the expression levels of selenium proteins GPx1 and TrxR1 by regulating selenium metabolism, thereby inhibiting viral replication and assembly and regulating virus-mediated mitochondria-related apoptosis. On the other hand, animal experiments show that RuSe can reduce lung tissue inflammation and inhibit lung tissue cell apoptosis in mice, and improve the survival state of mice. In addition, RuSe significantly improves the low immune response of Se-deficient mice by regulating selenium metabolism, and effectively alleviated lung fibrosis and lung tissue apoptosis in Se-deficient mice. Conclusions: This study suggests that RuSe provides a promising new approach for the clinical treatment of influenza virus.

Influenza antivirals and their role in pandemic preparedness

Effective antivirals provide crucial benefits during the early phase of an influenza pandemic, when vaccines are still being developed and manufactured. Currently, two classes of viral protein–targeting drugs, neuraminidase inhibitors and polymerase inhibitors, are approved for influenza treatment and post-exposure prophylaxis. Resistance to both classes has been documented, highlighting the need to develop novel antiviral options that may include both viral and host-targeted inhibitors. Such efforts will form the basis of management of seasonal influenza infections and of strategic planning for future influenza pandemics. This review focuses on the two classes of approved antivirals, their drawbacks, and ongoing work to characterize novel agents or combination therapy approaches to address these shortcomings. The importance of these topics in the ongoing process of influenza pandemic planning is also discussed.

505. Mucosal and Systemic Humoral Immunity Differences between Sexes during Influenza Vaccination and Viral Challenge

Abstract Background In previous influenza challenge studies we observed that the incidence of influenza symptoms was higher in women than in men, and that women experience more symptoms overall. Women also demonstrated lower neuraminidase (NA) inhibition (NAI) antibody titers than men after challenge and regression analysis suggested that NAI titers predict clinical outcomes. We sought to evaluate this using data from a more recent challenge study with more immunologically varied volunteers, while also assessing mucosal immunity. Methods We obtained mucosal and serum samples from healthy adults. Half underwent intramuscular quadrivalent influenza vaccination followed by influenza A (H1N1) intranasal challenge while others just challenge alone. Antibody titers and clinical outcomes between sexes were compared. Results No significant differences in shedding or symptom outcomes were observed between sexes. Similarly, no differences in systemic titers against NA or hemagglutinin (HA) were seen. Serum total IgG and IgA were also similar between sexes. Prior to vaccination, mucosal IgA titers were significantly lower against HA stalk and NA in women, but these differences disappeared after vaccination. In the unvaccinated group, lower nasal IgA titers were also seen in women pre-challenge. At 7 days post-challenge, differences in mucosal titers between sexes disappeared. However, at 56 days post-challenge, mucosal IgA titers against HA, HA stalk, and NA were all significantly lower in women. Conclusion In contrast to our previous findings, no differences in clinical outcomes or systemic NAI titers were observed between men and women, possibly due to differences in underlying immunity between study populations or the lower sample size in this study. However, mucosal differences were noted with women having lower mucosal titers than men against HA stalk and NA at baseline. While influenza vaccination and challenge eliminated differences in the short term, they reappeared 8 weeks after challenge, with all nasal IgA antibody titers (HA, HA stalk, and NA) lower in women. Further studies are necessary to understand the differences in influenza disease and immunity between sexes. Disclosures All Authors: No reported disclosures.

Initial and severe cases of influenza in 2020-2022 and population immunity prior to epidemic season

The purpose of the present work was to evaluate population immunity to influenza and molecular genetic analysis of influenza viruses detected in the Russian Federation over 2020-2022. In this study, 1344 samples of blood serum collected prior to the 2021-2022 flu season in Siberian, Southern, Far Eastern, Volga and Ural Federal Districts were studied. Seropositivity to the A/Victoria/2570/2019 vaccine strain (H1N1) pdm09 was detected in 25% to 31% of samples from the four federal districts, and in 8% of samples from the Far Eastern Federal District. Seropositivity to the A/Cambodia/e0826360/2020 strain (H3N2) was detected in 24% to 37% of the samples. The lowest population immunity was revealed to the influenza B/Washington/02/2019 vaccine strain (Victoria lineage), with < 10% of serum samples reactive to the studied strain. Since March 2020, the worldwide turnover of all seasonal respiratory viruses has sharply decreased, except of rhinoviruses. From March 2020 to June 2021, we have identified six B/Victoria influenza viruses from sporadic cases of influenza. From June 2021 to the end February 2022, the State Research Center “Vector” received 901 samples positive for influenza A(H3N2) virus RNA, two specimens positive for A(H1N1) pdm09 virus RNA, and 17 samples positive for influenza B. All studied A(H3N2) viruses belonged to the 3C.2a1b.2a2 subclade (Bangladesh group). The two verified A(H1N1) pdm09 influenza viruses belonged to the 6B.1A.5a clade. All studied influenza B viruses were assigned to the B/Victoria genetic lineage, and to 1A.3a2 subclade. The genomes of all identified viruses did not contain mutations of the NA gene responsible for drug resistance to neuraminidase inhibitors, or mutations in РA gene responsible for baloxavir resistance. All viruses tested by fluorescence assay were sensitive to oseltamivir and zanamivir. The worldwide frequency of influenza isolates resistant to antineuraminidase drugs does not exceed 1-2% of cases. Hence, oseltamivir and zanamivir provide effective treatment for seasonal influenza.

Rapid screening of neuraminidase inhibitors using an at-line nanofractionation platform involving parallel oseltamivir-sensitive/resistant neuraminidase bioassays

In this study, an advanced at-line nanofractionation based screening platform was developed to screen potential neuraminidase inhibitors (NAIs) from Lonicera japonica Thunb by involving two parallel bioassays, for determining both oseltamivir-sensitive neuraminidase (NAS) and oseltamivir-resistant neuraminidase (NAR) inhibitory activities. 20 potential NAIs with both NAS and NAR inhibitory effects were screened from Lonicera japonica Thunb and identified by mass spectrometer, including 11 phenolic acids, 8 flavonoids and one iridoid glycoside. The proposed at-line nanofractionation based screening platform for NAIs was also used to rapidly screen nine batches of water extracts of Lonicera japonica Thunb or its similar species. Clear differences in the number and content of active components were easily observed, demonstrating that the proposed method possesses great potential for the quality control of herb medicines.

Development of a sensitive and selective bioanalytical method of chebulinic acid by liquid chromatography‐electrospray tandem mass spectrometry and its pharmacokinetic application

AbstractChebulinic acid (CA), a polyphenolic compound extracted from the fruits of Terminalia chebula, has been recently reported as a novel neuraminidase inhibitor against the influenza A virus and also for various biological activities that require pharmacokinetic estimation. We report a proposed fragmentation pathway for the formation and selection of sodium and ammonium adducts using molecular thermodynamics. The chebulinic acid ammonium adduct was reproducible and stable compared to the earlier reported sodium adduct to quantify chebulinic acid by liquid chromatography‐tandem mass spectrometry. Chebulinic acid was extracted from plasma by protein precipitation followed by single‐step liquid‐liquid extraction by removing interfering metal adducts such as sodium. chebulinic acid resolution was achieved from the C18 column with mobile phase acetonitrile: methanol mixture and ammonium acetate buffer at a flow rate of 0.5 ml/min. The linear calibration curve (r2 ≥ 0.995) range was 3.52–1800 ng/ml. Finally, we report the oral pharmacokinetic profile of chebulinic acid in male Swiss albino mice plasma using the developed method.

Diagnosis and treatment of influenza: a literature review

Alisa Pozniak1 1Vilnius University, Faculty of Medicine, Vilnius, Lithuania Abstract Background. Influenza is an acute viral respiratory infection. Influenza viruses spread through respiratory droplets and are characterized by frequent mutations that lead to antigenicity changes. According to the World Health Organization, seasonal influenza epidemics cause approximately 4 million cases of severe illness and 250,000 to 500,000 deaths each year globally. Aim: to review the diagnosis and treatment of influenza. Methodology: literature sources were selected from PubMed database following dates from 2017 to 2022 using keywords and their combinations: influenza, rapid antigen test, neuraminidase inhibitors, favipiravir, baloxavir. Results. Influenza should be suspected in patients who develop acute respiratory symptoms during the influenza season. Diagnostic tests available for influenza include rapid antigen and molecular tests, polymerase chain reaction tests, virological culture. Antiviral therapy should be initiated in patients who are at increased risk of complications from influenza. The neuraminidase inhibitors zanamivir and oseltamivir are used for specific antiviral therapy. New antivirals such as peramivir, favipiravir, laninamivir and baloxavir have emerged as a promising new treatment approach. Conclusions. Influenza is a serious infectious disease that can lead to life-threatening complications. Virological diagnosis is based on specific epidemiological data, clinical symptoms and laboratory tests. Neuraminidase inhibitors are recommended for early treatment. Several cases of zanamivir and oseltamivir-resistant virus have been reported. That is the reason why different approaches for antiviral treatment are being investigated. Keywords: influenza, rapid antigen test, neuraminidase inhibitors, favipiravir, baloxavir.

Nonpharmaceutical interventions for COVID-19 disrupt the dynamic balance between influenza A virus and human immunity.

During the COVID-19 epidemic, nonpharmaceutical interventions (NPIs) blocked the transmission route of respiratory diseases. This study aimed to investigate the impact of NPIs on the influenza A virus (IAV) outbreak. The present study enrolled all children with respiratory tract infections who came to the Children's Hospital of Zhejiang University between January 2019 and July 2022. A direct immunofluorescence assay kit detected IAV. Virus isolation and Sanger sequencing were performed. From June to July 2022, in Hangzhou, China, the positive rate of IAV infection in children has increased rapidly, reaching 30.41%, and children over 3 years old are the main infected population, accounting for 75% of the total number of infected children. Influenza A (H3N2) viruses are representative strains during this period. In this outbreak, H3N2 was isolated from a cluster of its own and is highly homologous with A/South_Dakota/22/2022 (2021-2022 Northern Hemisphere). Between isolated influenza A (H3N2) viruses and A/South_Dakota/22/2022, the nucleotide homology of the HA gene ranged from 97.3% to 97.5%; the amino acid homology was 97%-97.2%, and the genetic distance of nucleotides ranged from 0.05 to 0.052. Compared with A/South_Dakota/22/2022, the isolated H3N2 showed S156H, N159Y, I160T, D186S, S198P, I48T, S53D, and K171N mutations. There was no variation in 13 key amino acid sites associated with neuraminidase inhibitor resistance in NA protein. Long-term NPIs have significantly affected the evolution and transmission of the influenza virus and human immunity, breaking the dynamic balance between the IAV and human immunity.

Shear Stress Promotes Platelet Surface Desialylation, Platelet Count Drop, and Microvesiculation: Do Platelets Need to be Sugar-Coated?

Introduction. Mechanical circulatory support (MCS) devices restore hemodynamics and are lifesaving for patients with advanced heart failure and, recently, for patients with severe COVID-19. Long-term MCS is associated with bleeding complications, often requiring multiple transfusions of blood products or reoperations. To date, due to undefined etiology, device-related bleeding lacks efficient therapeutic management. We have shown that hypershear stress, existing within device-supported circulation promotes platelet dysfunction associated with pro-apoptosis, downregulation of key adhesion receptors, impaired platelet aggregation, and microvesiculation - all contributors to bleeding. Recent studies have also shown that glycosylation of platelet surface receptors, i.e. the platelet "sugar coat," plays a major role in the regulation of platelet function and lifespan. Here, we tested the hypothesis that hypershear stress promotes platelet surface desialylation, thus facilitating platelet count drop and increased microvesiculation. Methods. Human platelets were obtained from ACD-anticoagulated blood of healthy volunteers via gel filtration on Sepharose 2B. Gel-filtered platelets were exposed to neuraminidase and continuous shear stress (30 or 70 dyne/cm2,10 min) in a hemodynamic shearing device. Optionally, platelets were pretreated with oseltamivir, a common neuraminidase inhibitor. Platelets were co-stained with fluorophore-conjugated SNA lectin, binding terminal 2,6-linked sialic acid moieties, and anti-CD41 antibody. Multi-colored flow cytometry was performed to quantify platelet surface sialylation, platelets, and microparticles; fluorescent nanobeads SPHEROTM were used as a size standard. The surface density of platelet sialylation was calculated as median fluorescence intensity normalized to forward scatter indicating platelet size. The platelet neuraminidase activity was quantified using fluorogenic substrate 4-methylumbelliferyl-N-acetylneuraminic acid (MUNANA) and was presented as µM of substrate per min. Results. Platelet exposure to both hypershear stress and neuraminidase-1 induced platelet surface desialylation as indicated by the significant decrease of SNA lectins' binding density on platelets (Fig.1A). Platelet desialylation induced by shear stress and neuraminidase was associated with a notable decrease in platelet count and an increase in platelet-derived microparticles (Fig.1B). Interestingly, neuraminidase reinforced shear-mediated desialylation, platelet count drop, and microvesiculation. Oseltamivir slightly inhibited shear-mediated desialylation, preserved platelet count (30% increase vs. shear), and decreased microparticle generation (29% decrease vs. shear). Exposure to 70 dyne/cm2 shear stress resulted in a 9.5-fold increase in platelet neuraminidase activity as compared to basal level: 0.85 ± 0.61 µM/min vs 0.05 ± 0.03 µM/min, respectively (Mean ± SD, p < 0.01, one-way ANOVA). Conclusions. Shear stress promotes platelet surface desialylation with the associated reduction in platelet count and increased microvesiculation. Neuraminidase inhibition restores platelet count and decreases microparticle generation caused by hypershear. Shear-mediated increase of platelet neuraminidase activity is considered a plausible mechanism for shear-mediated platelet deglycosylation. Developing therapeutic strategies for preservation of platelet sialylation offers significant translational potential for pharmacologic management of MCS-related platelet dysfunction and bleeding coagulopathy. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Enabling oral delivery of antiviral drugs: Double emulsion carriers to improve the intestinal absorption of zanamivir

Antiviral drugs play a major role in the control of seasonal influenza epidemics and may provide prophylactic and therapeutic benefits during an eventual pandemic. Among the neuraminidase inhibitors, zanamivir has been shown to be a potent inhibitor of influenza viruses, and similarly against emerging resistant strains. Despite its high antiviral efficiency, zanamivir suffers from poor intestinal permeability, therefore administered via inhalation. Enabling oral delivery of zanamivir will augment the available antiviral tools in clinical practice, increase patient compliance and ultimately improve public health. Encapsulation of hydrophilic drugs within double emulsions (DEs), is an efficacious approach to enhance the oral bioavailability of BCS Class III drugs, such as zanamivir. The objective of this research was to increase the intestinal absorption of zanamivir by means of compatible DEs. Two different types of stable DEs were prepared comprising different internal aqueous phases (W1). These micro-sized DEs showed high encapsulation efficacy (96.6–98.9 %) and markedlyretardedtherelease rateof the antiviral drug. Both types of the zanamivir loaded DEs (zDEs) significantly increased the transport ability of zanamivir across a parallel artificial membrane. Furthermore, in-situ perfusion of zDEs revealed outstanding permeability of zanamivir across the intestinal wall of rats. The zDEs containing carbomer gel (rather than carboxymethyl cellulose) as W1 obtained superior in-vivo effective permeability (Peff); yet, both zDEs exhibited higher Peff values (2–6-fold) than the low/high permeability marker (metoprolol). In conclusion, the DEs delivery system allowed overcoming the intestinal permeability barriers, towards successful oral administration of zanamivir.

Platelet Desialylation Is a Novel Mechanism and Therapeutic Target in Daboia siamensis and Agkistrodon halys Envenomation-Induced Thrombocytopenia.

Venom-induced thrombocytopenia (VIT) is one of the most important hemotoxic effects of a snakebite, which is often associated with venom-induced consumptive coagulopathy (VICC). Refractory thrombocytopenia without significant coagulation abnormalities has also been reported after envenomation by some viperid snakes; however, the mechanisms are not well understood and therapeutic strategies are lacking. Here, we found that patients injured by Daboia siamensis or Agkistrodon halys snakes, who were resistant to standard antivenom treatment, had developed coagulopathy-independent thrombocytopenia. Venoms from these viperid snakes, rather than from the elapid snake (Bungarus multicinctus), induced platelet surface expression of neuraminidase-1 (NEU-1), and significantly increased the desialylation of the glycoproteins on human platelets. The desialylated platelets caused by viperid snake venoms were further internalized by macrophages, which resulted in reduced platelet numbers in peripheral blood. Importantly, neuraminidase inhibitor significantly decreased viper venom-induced platelet desialylation, therefore inhibiting platelet phagocytosis by macrophages, and alleviating venom-induced thrombocytopenia. Collectively, these findings support an important role for desialylated platelet clearance in the progression of viper envenomation-induced, coagulopathy-independent thrombocytopenia. Our study demonstrates that the neuraminidase inhibitor may be a potential therapy or adjuvant therapy to treat snakebite-induced thrombocytopenia.

Preparing for pandemics: a systematic review of pandemic influenza clinical management guidelines

BackgroundThe COVID-19 pandemic has highlighted the importance of evidence-based clinical decision-making. Clinical management guidelines (CMGs) may help reduce morbidity and mortality by improving the quality of clinical decisions. This systematic review aims to evaluate the availability, inclusivity, and quality of pandemic influenza CMGs, to identify gaps that can be addressed to strengthen pandemic preparedness in this area.MethodsOvid Medline, Ovid Embase, TRIP (Turning Research Into Practice), and Guideline Central were searched systematically from January 2008 to 23rd June 2022, complemented by a grey literature search till 16th June 2022. Pandemic influenza CMGs including supportive care or empirical treatment recommendations were included. Two reviewers independently extracted data from the included studies and assessed their quality using AGREE II (Appraisal of Guidelines for Research & Evaluation). The findings are presented narratively.ResultsForty-eight CMGs were included. They were produced in high- (42%, 20/48), upper-middle- (40%, 19/48), and lower-middle (8%, 4/48) income countries, or by international organisations (10%, 5/48). Most CMGs (81%, 39/48) were over 5 years old. Guidelines included treatment recommendations for children (75%, 36/48), pregnant women (54%, 26/48), people with immunosuppression (33%, 16/48), and older adults (29%, 14/48). Many CMGs were of low quality (median overall score: 3 out of 7 (range 1–7). All recommended oseltamivir; recommendations for other neuraminidase inhibitors and supportive care were limited and at times contradictory. Only 56% (27/48) and 27% (13/48) addressed oxygen and fluid therapy, respectively.ConclusionsOur data highlights the limited availability of up-to-date pandemic influenza CMGs globally. Of those identified, many were limited in scope and quality and several lacked recommendations for specific at-risk populations. Recommendations on supportive care, the mainstay of treatment, were limited and heterogeneous. The most recent guideline highlighted that the evidence-base to support antiviral treatment recommendations is still limited. There is an urgent need for trials into treatment and supportive care strategies including for different risk populations. New evidence should be incorporated into globally accessible guidelines, to benefit patient outcomes. A ‘living guideline’ framework is recommended and further research into guideline implementation in different resourced settings, particularly low- and middle-income countries.