Influenza virus-related critical illness: pathophysiology and epidemiology

Alloferon and Zanamivir Show Effective Antiviral Activity against Influenza A Virus (H1N1) Infection In Vitro and In Vivo

The use of vaccines is the most effective and reliable method for the prevention of viral infections. However, research on evaluation of effective therapeutic agents for use in treatment after infection is necessary. Zanamivir was administered through inhalation for treatment of pandemic influenza A/H1N1 in 2009. However, the emergence of drug-resistant strains can occur rapidly. Alloferon, an immunomodulatory drug developed as an NK cell activator, exerts antiviral effects against various viruses, particularly influenza viruses. Therefore, alloferon and zanamivir were administered in combination in an effort to improve the antiviral effect of zanamivir by reducing H1N1 resistance. First, we confirmed that administration of combined treatment would result in effective inhibition of viral proliferation in MDCK and A549 cells infected with H1N1. Production of IL-6 and MIP-1α in these cells and the activity of p38 MAPK and c-Jun that are increased by H1N1 were inhibited by combined treatment. Mice were then infected intranasally with H1N1, and examination of the antiviral efficacy of the alloferon/zanamivir combination was performed. The results showed that combined treatment after infection with H1N1 prevented weight loss, increased the survival rate, and improved lung fibrosis. Combined treatment also resulted in reduced infiltration of neutrophils and macrophages into the lungs. Combined treatment effectively inhibited the activity of p38 MAPK and c-Jun in lung tissue, which was increased by infection with H1N1. Therefore, the combination of alloferon/zanamivir effectively prevents the development of H1N1-mediated inflammation in the lungs by inhibiting the production of inflammatory mediators and migration of inflammatory cells into lung tissue.

Enhanced activity of NLRP3 inflammasome and its proinflammatory effect in influenza A viral pneumonia

Aim: The aim of this study was to investigate the activity of NLRP3 inflammasome and its effect on inducing severe pneumonia 1 week after influenza A virus (IAV) infection. Materials & methods: The expression levels of NLRP3, caspase-1 and IL-1β were assessed in murine macrophages stimulated with IAV. And the severity of viral pneumonia in mice was explored. Results & conclusion: The data showed that although the expression of NLRP3 diverged, activity of NLRP3 inflammasome was enhanced 1 week after IAV infection, and more severe viral pneumonia was associated with IL-1β in serum. It infers that enhanced activity of NLRP3 inflammasome induces augmented expression of IL-1β and severe pneumonia in a NLRP3-independent way, 1 week after IAV infection.

Comparison of Fragments in Human Hemostatic Proteins That Mimics Fragments in Proteins of A/H1N1 Viruses and Coronaviruses

Objective: To compare the repertoire of proteins of the human hemostatic system and fragments mimicking these proteins in the proteins of influenza A/H1N1 viruses and coronaviruses. Material and methods. Influenza viruses A/H1N1 (A/Brevig Mission/1/18), A/St. Petersburg /RII04/2016 (H1N1)pdm09, coronaviruses SARS-CoV and SARS-CoV-2 (strain Wuhan-Hu-1) were used for comparative computer analysis. The sources of the primary structures of proteins of the analyzed viruses and 41 proteins of the human hemostatic system were publicly available Internet databases, respectively, www.ncbi.nlm.nih.gov and www.nextprot.org. The search for homologous sequences in the structure of viral proteins and hemostatic proteins was carried out by comparing fragments of 12 amino acids in length, taking as related those that showed identity at ≥8 positions. Results. Comparative analysis of the repertoire of cellular proteins of the hemostatic system and fragments mimicking these proteins in the structure of proteins of viruses A/H1N1 1918, A(H1N1)pdm09 isolated in 2016, SARS-CoV and SARS-CoV-2, showed a significant difference between SARS-CoV-2 and analyzed viruses. In the protein structure of the SARS-CoV-2 virus, mimicry was revealed for almost all analyzed hemostasis proteins. As for the comparison of viruses A/H1N1 1918, A(H1N1)pdm09 2016 and SARS-CoV, the influenza virus A/H1N1 1918 and SARS-CoV are the closest in the repertoire of hemostatic proteins. Conclusion. Obtained bioinformatic analysis data can serve as a basis for further study of the role of homologous fragments in the regulation of hemostasis of the host organism.

Airway Epithelial Cell Junctions as Targets for Pathogens and Antimicrobial Therapy

Intercellular contacts between epithelial cells are established and maintained by the apical junctional complexes (AJCs). AJCs conserve cell polarity and build epithelial barriers to pathogens, inhaled allergens, and environmental particles in the respiratory tract. AJCs consist of tight junctions (TJs) and adherens junctions (AJs), which play a key role in maintaining the integrity of the airway barrier. Emerging evidence has shown that different microorganisms cause airway barrier dysfunction by targeting TJ and AJ proteins. This review discusses the pathophysiologic mechanisms by which several microorganisms (bacteria and viruses) lead to the disruption of AJCs in airway epithelial cells. We present recent progress in understanding signaling pathways involved in the formation and regulation of cell junctions. We also summarize the potential chemical inhibitors and pharmacological approaches to restore the integrity of the airway epithelial barrier. Understanding the AJCs-pathogen interactions and mechanisms by which microorganisms target the AJC and impair barrier function may further help design therapeutic innovations to treat these infections.

Lianhuaqingwen capsule inhibits non-lethal doses of influenza virus-induced secondary Staphylococcus aureus infection in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Lianhuaqingwen capsule (LH-C) is a traditional Chinese medicine (TCM), consisting of two prescriptions, Ma-xing-shi-gan-tang (MXSGT) and Yinqiao San. It has been proven to have antiviral, antibacterial, and immunomodulatory effects in recent years. Clinically, it is commonly used in the treatment of respiratory tract infections.

AIM OF THE STUDY

It was demonstrated in our previous studies that LH-C has an effect of antivirus and inhibits influenza virus-induced bacterial adhesion to respiratory epithelial cells through down-regulation of cell adhesion molecules in vitro. However, LH-C's effect against influenza-induced secondary bacterial infection in animal studies remains unclear. Therefore, in the present study, we established a mouse model of infection with non-lethal doses of influenza virus(H1N1) and secondary infection of Staphylococcus aureus (S. aureus), to investigate the potential effects of LH-C.

METHODS

Experiments were carried out on BALB/c mice infecting non-lethal doses of H1N1 and non-lethal doses of S. aureus, and the viral, and bacterial doses were determined by observing and recording changes in the body weight, mortality, and pathological changes. Moreover, after LH-C treatment, the survival rate, body weight, lung index, viral titers, bacterial colonies, pathological changes, and the inflammatory cytokines in the mouse model have all been systematically determined.

RESULTS

In the superinfection models of H1N1 and S. aureus, the mortality rate was 100% in groups of mice infected with 20 PFU/50 μL of H1N1 and 10⁵ CFU/mL of S. aureus, 20 PFU/50 μL of H1N1 and 10⁶ CFU/mL of S. aureus, 4 PFU/50 μL of H1N1 and 10⁶ CFU/mL of S. aureus. The mortality rate was 50% in the group of mice infected with 4 PFU/50 μL of H1N1 and 10⁵ CFU/mL of S. aureus. The mortality rate was 37.5% in the group of mice infected with 20 PFU/50 μL of H1N1 alone and in the group of mice infected with 2 PFU/50 μL of H1N1 and 10⁶ CFU/mL of S. aureus. The mortality rate in the group of mice infected with 2 PFU/50 μL of H1N1 and 10⁶ CFU/mL of S. aureus was 30%. The infected mice of 2 PFU/50 μL of H1N1 and 10⁶ CFU/mL of S. aureus had a weight loss of nearly 10%. About the histopathological changes in the lung tissue of infection mice, severe lung lesions were found in the superinfection models. LH-C improved survival in the superinfected mice, significantly reduced lung index, lowered viral titers and bacterial loads, and alleviated lung damage. It reduced lung inflammation by down-regulating mRNA expression levels of inflammatory mediators like IL-6, IL-1β, IL-10, TNF-α, IFN-β, MCP-1, and RANTES.

CONCLUSIONS

We found that superinfection from non-lethal doses of S. aureus following non-lethal doses of H1N1 was equally fatal in mice, confirming the severity of secondary infections. The ability of LH-C to alleviate lung injury resulting from secondary S. aureus infection induced by H1N1 was confirmed. These findings provided a further assessment of LH-C, suggesting that LH-C may have good therapeutic efficacy in influenza secondary bacterial infection disease.

Anti-inflammatory effects of Chaishi Tuire Granules on influenza A treatment by mediating TRAF6/MAPK14 axis

Objectives

Influenza is an infectious respiratory disease that can cause severe inflammatory reactions and threaten human life. Chaishi Tuire Granules (CSTRG), a Chinese patent medicine widely used clinically in the treatment of respiratory diseases in China, has a definite anti-inflammatory effect. However, the mechanism of CSTRG in the treatment of influenza is still unclear. This study aimed to demonstrate the anti-inflammatory effect of CSTRG on influenza A treatment and potential mechanisms.

Methods

Influenza-associated mice pneumonia model was used to explore the antiviral and anti-inflammatory effects of CSTRG in vivo. Bioinformatics analysis methods such as network pharmacology and molecular docking were carried out to predict the main active components and potential anti-inflammatory targets of CSTRG. The anti-inflammatory activity of CSTRG was determined using the lipopolysaccharide (LPS)-induced macrophages RAW264.7 cells in vitro.

Results

In vivo results showed that CSTRG can reduce the viral load in the lung tissue of infected mice, reduce the expression of TNF-α and IL-6 in lung tissue and serum, and regulate the host inflammatory response. Additionally, CSTRG treatment markedly improves the sick signs, weight loss, lung index, and lung pathological changes. Bioinformatics analysis predicted that six active compounds of CSTRG including quercetin, kaempferol, luteolin, beta-sitosterol, sitosterol, and stigmasterol could contribute to the anti-influenza activity through regulating the TRAF6/MAPK14 axis. The following research confirmed that CSTRG significantly inhibited pro-inflammatory cytokines (TNF-α and IL-6) by suppressing the expression of TRAF6 and MAPK14 in LPS-stimulated macrophages RAW264.7 cells.

Conclusion

CSTRG might inhibit the inflammatory response by mediating the TRAF6/MAPK14 axis. In the future, in-depth research is still needed to verify the mechanism of CSTRG in the treatment of influenza.

Tumor Progression Locus 2 Protects against Acute Respiratory Distress Syndrome in Influenza A Virus-Infected Mice

Excessive inflammation in patients with severe influenza disease may lead to acute lung injury that results in acute respiratory distress syndrome (ARDS). ARDS is associated with alveolar damage and pulmonary edema that severely impair gas exchange, leading to hypoxia. With no existing FDA-approved treatment for ARDS, it is important to understand the factors that lead to virus-induced ARDS development to improve prevention, diagnosis, and treatment. We have previously shown that mice deficient in the serine-threonine mitogen-activated protein kinase, Tpl2 (MAP3K8 or COT), succumb to infection with a typically low-pathogenicity strain of influenza A virus (IAV; HKX31, H3N2 [x31]). The goal of the current study was to evaluate influenza A virus-infected Tpl2-/- mice clinically and histopathologically to gain insight into the disease mechanism. We hypothesized that Tpl2-/- mice succumb to IAV infection due to development of ARDS-like disease and pulmonary dysfunction. We observed prominent signs of alveolar septal necrosis, hyaline membranes, pleuritis, edema, and higher lactate dehydrogenase (LDH) levels in the lungs of IAV-infected Tpl2-/- mice compared to wild-type (WT) mice from 7 to 9 days postinfection (dpi). Notably, WT mice showed signs of regenerating epithelium, indicative of repair and recovery, that were reduced in Tpl2-/- mice. Furthermore, biomarkers associated with human ARDS cases were upregulated in Tpl2-/- mice at 7 dpi, demonstrating an ARDS-like phenotype in Tpl2-/- mice in response to IAV infection. IMPORTANCE This study demonstrates the protective role of the serine-threonine mitogen-activated protein kinase, Tpl2, in influenza virus pathogenesis and reveals that host Tpl2 deficiency is sufficient to convert a low-pathogenicity influenza A virus infection into severe influenza disease that resembles ARDS, both histopathologically and transcriptionally. The IAV-infected Tpl2-/- mouse thereby represents a novel murine model for studying ARDS-like disease that could improve our understanding of this aggressive disease and assist in the design of better diagnostics and treatments.

Reduced platelet mitochondrial respiration and oxidative phosphorylation in patients with post COVID-19 syndrome are regenerated after spa rehabilitation and targeted ubiquinol therapy

European Association of Spa Rehabilitation recommend spa rehabilitation for patients with post COVID-19 syndrome (post C-19). We studied effects of special mountain spa rehabilitation program and its combination with ubiquinol (reduced form of coenzyme Q10-CoQ10) supplementation on pulmonary function, clinical symptoms, endogenous CoQ10 levels, and platelet mitochondrial bioenergetics of patients with post C-19. 36 patients with post C-19 enrolled for rehabilitation in mountain spa resort and 15 healthy volunteers representing the control group were included in this study. 14 patients with post C-19 (MR group) were on mountain spa rehabilitation lasting 16-18 days, 22 patients (MRQ group) were supplemented with ubiquinol (2 × 100 mg/day) during the rehabilitation and additional 12-14 days at home. Clinical symptoms and functional capacity of the lungs were determined in the patients before and after the spa rehabilitation program. Platelet bioenergetics by high-resolution respirometry, plasma TBARS concentration, and CoQ10 concentration in blood, plasma and platelets were evaluated before and after the spa rehabilitation program, and in 8 patients of MRQ group also after additional 12-14 days of CoQ10 supplementation. Pulmonary function and clinical symptoms improved after the rehabilitation program in both groups, 51.8% of symptoms disappeared in the MR group and 62.8% in the MRQ group. Platelet mitochondrial Complex I (CI)-linked oxidative phosphorylation (OXPHOS) and electron transfer (ET) capacity were markedly reduced in both groups of patients. After the rehabilitation program the improvement of these parameters was significant in the MRQ group and moderate in the MR group. CI-linked OXPHOS and ET capacity increased further after additional 12-14 days of CoQ10 supplementation. CoQ10 concentration in platelets, blood and plasma markedly raised after the spa rehabilitation with ubiquinol supplementation, not in non-supplemented group. In the MRQ group all parameters of platelet mitochondrial respiration correlated with CoQ10 concentration in platelets, and the increase in CI-linked OXPHOS and ET capacity correlated with the increase of CoQ10 concentration in platelets. Our data show a significant role of supplemented ubiquinol in accelerating the recovery of mitochondrial health in patients with post C-19. Mountain spa rehabilitation with coenzyme Q10 supplementation could be recommended to patients with post C-19. This study was registered as a clinical trial: ClinicalTrials.gov ID: NCT05178225.

Qin-Qiao-Xiao-Du formula alleviate influenza virus infectious pneumonia through regulation gut microbiota and metabolomics

Qin-Qiao-Xiao-Du (QQXD), a traditional Chinese medicine (TCM) formula, has been used in the clinical treatment of influenza virus pneumonia. However, the effects and mechanisms of QQXD on influenza virus pneumonia remain unknown. Therefore, this study explores the mechanisms of QQXD in the treatment of influenza virus pneumonia from the point of view of intestinal flora and metabolism. The results showed that QQXD was able to reduce mortality, weight loss, lung viral load, lung index, and lung injury in influenza virus mice. A cytokine array found that the QQXD attenuated the expression of serum IL-1α, IL-4, IL-12(P70), and TNF-α. Subsequently, 16s rRNA gene sequencing showed that QQXD could increase the relative abundances of Gemmiger, Anaerofustis, Adlercreutzia, and Streptococcus and decrease those of Dehalobacteriu, Burkholderia, Prevotella, Butyrimimonas, Delftia, and others. Meanwhile, targeted metabolic profiling analysis showed that QQXD could regulate nitrogen metabolism, phenylalanine metabolism, valine, leucine, and isoleucine biosynthesis. Correlation analysis demonstrated that the regulatory effect of QQXD on the cyanoamino acid metabolism pathway was associated with changes in the abundance of Parabacteroides, Pediococcus, and Clostridium in influenza mice. In conclusion, our study revealed that QQXD can inhibit influenza virus replication, suppress cytokine storms, and protect mice from influenza virus infection pneumonia. The mechanisms are likely to be related to improved gut microbiota dysbiosis, increased intestinal carbohydrate metabolism, and up-regulated cyanoamino acid metabolism pathways.

A Dual Adjuvant System for Intranasal Boosting of Local and Systemic Immunity for Influenza Vaccination

Systemically vaccinated individuals against COVID-19 and influenza may continue to support viral replication and shedding in the upper airways, contributing to the spread of infections. Thus, a vaccine regimen that enhances mucosal immunity in the respiratory mucosa is needed to prevent a pandemic. Intranasal/pulmonary (IN) vaccines can promote mucosal immunity by promoting IgA secretion at the infection site. Here, we demonstrate that an intramuscular (IM) priming-IN boosting regimen with an inactivated influenza A virus adjuvanted with the liposomal dual TLR4/7 adjuvant (Fos47) enhances systemic and local/mucosal immunity. The IN boosting with Fos47 (IN-Fos47) enhanced antigen-specific IgA secretion in the upper and lower respiratory tracts compared to the IM boosting with Fos47 (IM-Fos47). The secreted IgA induced by IN-Fos47 was also cross-reactive to multiple influenza virus strains. Antigen-specific tissue-resident memory T cells in the lung were increased after IN boosting with Fos47, indicating that IN-Fos47 established tissue-resident T cells. Furthermore, IN-Fos47 induced systemic cross-reactive IgG antibody titers comparable to those of IM-Fos47. Neither local nor systemic reactogenicity or adverse effects were observed after IN delivery of Fos47. Collectively, these results indicate that the IM/IN regimen with Fos47 is safe and provides both local and systemic anti-influenza immune responses.

Network pharmacology study to reveal active compounds of Qinggan Yin formula against pulmonary inflammation by inhibiting MAPK activation

ETHNOPHARMACOLOGICAL RELEVANCE

Pneumonia is common and frequently-occurred disease caused by pathogens which predisposes to lung parenchymal inflammation leading pulmonary dysfunction. To prevent and alleviate the symptoms of pneumonia, Qinggan Yin formula (QGY) was composed based on clinical experience and four classical traditional Chinese medicine prescriptions which frequently applied to treat infectious diseases.

AIM OF THE STUDY

Traditional Chinese medicine is a complex mixture and it is difficult to distinguish the effective component molecules. The aim of this study is to identify the compounds of QGY with anti-inflammatory effects and investigate the molecular mechanism.

MATERIALS AND METHODS

The high-resolution mass spectrometry and molecular networking were performed for comprehensive chemical profiling of QGY. Network pharmacology was used to generate "herbal-target-pathway" network for target predictions. The anti-inflammation effects of QGY were evaluated in mice model of lipopolysaccharide (LPS) induced acute inflammation. Tail transected zebrafish was also employed to validate macrophage migration reversed effect of QGY. Based on the molecular enrichment analysis, the active substances of QGY with anti-inflammatory effects were further identified in cellular model of macrophage activation. The mechanisms of active substances were investigated by testing their effects on the expression of correlated proteins by Western blot.

RESULTS

In total, 71 compounds are identified as major substances of QGY. According to the results of network pharmacology, QGY shows moderate anti-inflammatory effects and inhibit pulmonary injury. MAPK signaling pathway was predicted as the most related pathway regulated by QGY. Moreover, QGY significantly inhibit LPS-induced pulmonary inflammation in mice, and reversed macrophage migration toward the injury site in zebrafish. We also validate that some major compounds in QGY significantly attenuated the release of IL-1β, IL-6 and TNF-α in LPS-stimulated macrophage. Those active substances including acacetin and arctiin can inhibit the phosphorylation of ERK/JNK and down-regulated the protein expression of BCL-2.

CONCLUSION

Collectively, QGY possessed pronounced anti-inflammation effects. The integration of network pharmacology and experimental results indicated arctiin, iridin, acacetin, liquiritin, and arctigenin are major active substances of QGY with anti-inflammatory effects. The underlying mechanism of QGY involves MAPK signaling pathway and oxidative stress pathway.

Assessing the fitness of a dual-antiviral drug resistant human influenza virus in the ferret model

Influenza antivirals are important tools in our fight against annual influenza epidemics and future influenza pandemics. Combinations of antivirals may reduce the likelihood of drug resistance and improve clinical outcomes. Previously, two hospitalised immunocompromised influenza patients, who received a combination of a neuraminidase inhibitor and baloxavir marboxil, shed influenza viruses resistant to both drugs. Here-in, the replicative fitness of one of these A(H1N1)pdm09 virus isolates with dual resistance mutations (NA-H275Y and PA-I38T) was similar to wild type virus (WT) in vitro, but reduced in the upper respiratory tracts of challenged ferrets. The dual-mutant virus transmitted well between ferrets in an airborne transmission model, but was outcompeted by the WT when the two viruses were co-administered. These results indicate the dual-mutant virus had a moderate loss of viral fitness compared to the WT virus, suggesting that while person-to-person transmission of the dual-resistant virus may be possible, widespread community transmission is unlikely.

The emerging role of NOTCH3 receptor signalling in human lung diseases

The mammalian respiratory system or lung is a tree-like branching structure, and the main site of gas exchange with the external environment. Structurally, the lung is broadly classified into the proximal (or conducting) airways and the distal alveolar region, where the gas exchange occurs. In parallel with the respiratory tree, the pulmonary vasculature starts with large pulmonary arteries that subdivide rapidly ending in capillaries adjacent to alveolar structures to enable gas exchange. The NOTCH signalling pathway plays an important role in lung development, differentiation and regeneration post-injury. Signalling via the NOTCH pathway is mediated through activation of four NOTCH receptors (NOTCH1-4), with each receptor capable of regulating unique biological processes. Dysregulation of the NOTCH pathway has been associated with development and pathophysiology of multiple adult acute and chronic lung diseases. This includes accumulating evidence that alteration of NOTCH3 signalling plays an important role in the development and pathogenesis of chronic obstructive pulmonary disease, lung cancer, asthma, idiopathic pulmonary fibrosis and pulmonary arterial hypertension. Herein, we provide a comprehensive summary of the role of NOTCH3 signalling in regulating repair/regeneration of the adult lung, its association with development of lung disease and potential therapeutic strategies to target its signalling activity.

SARS-CoV-2 Brain Regional Detection, Histopathology, Gene Expression, and Immunomodulatory Changes in Decedents with COVID-19

Brains of 42 COVID-19 decedents and 107 non-COVID-19 controls were studied. RT-PCR screening of 16 regions from 20 COVID-19 autopsies found SARS-CoV-2 E gene viral sequences in 7 regions (2.5% of 320 samples), concentrated in 4/20 subjects (20%). Additional screening of olfactory bulb (OB), amygdala (AMY) and entorhinal area for E, N1, N2, RNA-dependent RNA polymerase, and S gene sequences detected one or more of these in OB in 8/21 subjects (38%). It is uncertain whether these RNA sequences represent viable virus. Significant histopathology was limited to 2/42 cases (4.8%), one with a large acute cerebral infarct and one with hemorrhagic encephalitis. Case-control RNAseq in OB and AMY found more than 5000 and 700 differentially expressed genes, respectively, unrelated to RT-PCR results; these involved immune response, neuronal constituents, and olfactory/taste receptor genes. Olfactory marker protein-1 reduction indicated COVID-19-related loss of OB olfactory mucosa afferents. Iba-1-immunoreactive microglia had reduced area fractions in cerebellar cortex and AMY, and cytokine arrays showed generalized downregulation in AMY and upregulation in blood serum in COVID-19 cases. Although OB is a major brain portal for SARS-CoV-2, COVID-19 brain changes are more likely due to blood-borne immune mediators and trans-synaptic gene expression changes arising from OB deafferentation.

Fulminant Influenza a Myocarditis Complicated by Transient Ventricular Wall Thickening and Cardiac Tamponade

Myocarditis is an infrequent complication of influenza infection that is most often diagnosed clinically in the setting of confirmed influenza infection and elevated cardiac enzymes. Pericarditis can also occur in cases of influenza myocarditis and may require pericardiocentesis for tamponade. Patients with fulminant myocarditis have cardiogenic shock; however, echocardiographic findings may be subtle, showing a preserved ejection fraction and diffuse left ventricular wall thickening (compared to baseline) due to inflammatory edema. Recognizing these echocardiographic findings in the appropriate clinical setting facilitates the early recognition of fulminant myocarditis. Therefore, we report a case of fulminant influenza A myocarditis in healthy 37-year-old women complicated by transient left ventricular wall thickening and tamponade, highlighting the importance of early diagnosis and supportive management for a successful outcome.

Cangma Huadu granules attenuate H1N1 virus-induced severe lung injury correlated with repressed apoptosis and altered gut microbiome

Severe influenza A virus infection leads to overwhelming inflammatory responses and cellular apoptosis, which causes lung injury and contributes to high mortality and morbidity. The gut microbiome altered in response to the infection might influence the disease progression and the treatment outcome. Cangma Huadu (CMHD) granules, an in-hospital preparation of traditional Chinese medicine, have been shown to be favorable in the clinical treatment of influenza. However, the effects and mechanisms of CMHD granules on severe influenza pneumonia and its mechanisms are not well-known. In this study, a lethal influenza A (H1N1) A/Puerto Rico/8/34 virus (PR8)-infected mice model was established, and the 16S ribosomal RNA (16S rRNA) V3–V4 region sequencing of the intestinal microbiome was conducted. We revealed that the oral administration of CMHD granules protects mice against higher mortality, enhanced weight loss, overwhelmed interferon-γ concentration, lung viral titers, and severe lung pathological injury in PR8-infected mice. CMHD granules’ administration downregulated the levels of interleukin (IL)-1β, tumor necrosis factor-α, and malondialdehyde, while it upregulated the levels of IL-10, superoxide dismutase, and glutathione peroxidase. Subsequently, it decreased the protein ratio of B-cell lymphoma-2/Bcl-2-associated X and the expression of cleaved caspase-3. The diversity and compositions of the gut microbes were altered profoundly after the administration of CMHD granules in PR8-infected mice. A higher abundance of Bifidobacterium, Parasutterella, Bacteroides, and Faecalibaculum was observed in the CMHD group, and a higher abundance of Lactobacillus and Turicibacter was observed in the positive drug Ribavirin group. The linear discriminant analysis effect size also revealed a higher proportion of Bacteroides and Bifidobacterium_pseudolongum characterized in the CMHD group. These results demonstrated that CMHD granules are a promising strategy for managing severe influenza and attenuating severe lung damage via reducing viral titer, inflammatory responses, and oxidative stress. The mechanisms are involved in repressed Bcl-2-regulated apoptosis and altered composition and diversity of the gut microbiome.

Potential probiotics for regulation of the gut-lung axis to prevent or alleviate influenza in vulnerable populations

Influenza, also known as "flu", is an infectious disease caused by influenza viruses. Three types of influenza virus, A, B, and C, are able to infect humans. In most people, influenza causes mild symptoms, but it can also induce severe complications and death. Annual influenza vaccines are currently the main intervention used to minimize mortality and morbidity. However, vaccination frequently fails to provide adequate protection, especially in the elderly. Traditional flu vaccine targets hemagglutinin to prevent virus infection, but the constant mutation of hemagglutinin means that it is a challenge to develop vaccines quickly enough to keep up with mutations. Thus, other methods of curbing influenza incidence would be welcomed, especially for vulnerable populations. Although influenza viruses primarily infect the respiratory tract, influenza virus infection also induces intestinal dysbiosis. Through gut microbiota-derived secreted products and the circulating immune cells, gut microbiota can affect pulmonary immunity. The crosstalk between the respiratory tract and gut microbiota, termed the "gut-lung axis", is observed in the regulation of immune responses against influenza virus infection or inflammation-induced lung damage, indicating the possibility of using probiotics to prevent influenza virus infection or alleviate respiratory symptoms. In this review, we summarize the current findings on the antiviral functions of particular probiotics and/or combinations and discuss the antiviral mechanisms and immunomodulatory activities of probiotics in vitro, in mice, and in humans. Clinical studies show probiotic supplements can provide health benefits, not only to the elderly or children with compromised immune systems, but also to young- and middle-aged adults.

Antimicrobial use and aetiology of bloodstream infections in critically ill patients during early stages of SARS-CoV-2 pandemic

Background

Aim

Methods

Findings

Conclusions

Prior influenza vaccine is not a risk factor for bacterial coinfection in patients admitted to the ICU due to severe influenza

OBJECTIVE

To determine whether the prior usage of the flu vaccine is a risk factor for bacterial co-infection in patients with severe influenza.

DESIGN

This was a retrospective observational cohort study of subjects admitted to the ICU. A propensity score matching, and logistic regression adjusted for potential confounders were carried out to evaluate the association between prior influenza vaccination and bacterial co-infection.

SETTINGS

184 ICUs in Spain due to severe influenza.

PATIENTS

Patients included in the Spanish prospective flu registry.

INTERVENTIONS

Flu vaccine prior to the hospital admission.

RESULTS

A total of 4175 subjects were included in the study. 489 (11.7%) received the flu vaccine prior to develop influenza infection. Prior vaccinated patients were older 71 [61-78], and predominantly male 65.4%, with at least one comorbid condition 88.5%. Prior vaccination was not associated with bacterial co-infection in the logistic regression model (OR: 1.017; 95%CI 0.803-1.288; p=0.885). After matching, the average treatment effect of prior influenza vaccine on bacterial co-infection was not statistically significant when assessed by propensity score matching (p=0.87), nearest neighbor matching (p=0.59) and inverse probability weighting (p=0.99).

CONCLUSIONS

No association was identified between prior influenza vaccine and bacterial coinfection in patients admitted to the ICU due to severe influenza. Post influenza vaccination studies are necessary to continue evaluating the possible benefits.

Influenza Myopericarditis and Pericarditis: A Literature Review

Myopericarditis is a rare complication of influenza infection. The presentation may range from mild and frequently unrecognized, to fulminant and potentially complicated by cardiogenic and/or obstructive shock (tamponade), which is associated with high mortality. We performed a review of literature on all influenza pericarditis and myopericarditis cases according to PRISMA guidelines using the PubMed search engine of the Medline database. Seventy-five cases of influenza myopericarditis and isolated pericarditis were identified from 1951 to 2021. Influenza A was reported twice as often as influenza B; however, influenza type did not correlate with outcome. Men and elderly patients were more likely to have isolated pericarditis, while women and younger patients were more likely to have myopericarditis. All included patients had pericardial effusion, while 36% had tamponade. Tamponade was more common in those with isolated pericarditis (41.2%) than myopericarditis (13.8%). Cardiogenic shock was more common in patients with myopericarditis (64%), with an overall mortality rate of 14.7%. Nearly 88% of the recovered patients remained without long-term complications reported. Conclusion: Influenza A appears a more common cause of pericarditis and myopericarditis. Isolated pericarditis was more commonly associated with tamponade but without reported deaths, whereas myopericarditis was more commonly associated with cardiogenic shock and death (19%).

Virus Infection and Systemic Inflammation: Lessons Learnt from COVID-19 and Beyond

Respiratory infections with newly emerging zoonotic viruses such as SARS-CoV-2, the etiological agent of COVID-19, often lead to the perturbation of the human innate and adaptive immune responses causing severe disease with high mortality. The responsible mechanisms are commonly virus-specific and often include either over-activated or delayed local interferon responses, which facilitate efficient viral replication in the primary target organ, systemic viral spread, and rapid onset of organ-specific and harmful inflammatory responses. Despite the distinct replication strategies, human infections with SARS-CoV-2 and highly pathogenic avian influenza viruses demonstrate remarkable similarities and differences regarding the mechanisms of immune induction, disease dynamics, as well as the long-term sequelae, which will be discussed in this review. In addition, we will highlight some important lessons about the effectiveness of antiviral and immunomodulatory therapeutic strategies that this pandemic has taught us.

Association between lipid profiles and viral respiratory infections in human sputum samples

Background

Respiratory infections such as influenza account for significant global mortality each year. Generating lipid profiles is a novel and emerging research approach that may provide new insights regarding the development and progression of priority respiratory infections. We hypothesized that select clusters of lipids in human sputum would be associated with specific viral infections (Influenza (H1N1, H3N2) or Rhinovirus).

Methods

Lipid identification and semi-quantitation was determined with liquid chromatography and high-resolution mass spectrometry in induced sputum from individuals with confirmed respiratory infections (influenza (H1N1, H3N2) or rhinovirus). Clusters of lipid species and associations between lipid profiles and the type of respiratory viral agent was determined using Bayesian profile regression and multinomial logistic regression.

Results

More than 600 lipid compounds were identified across the sputum samples with the most abundant lipid classes identified as triglycerides (TG), phosphatidylethanolamines (PE), phosphatidylcholines (PC), Sphingomyelins (SM), ether-PC, and ether-PE. A total of 12 lipid species were significantly different when stratified by infection type and included acylcarnitine (AcCar) (10:1, 16:1, 18:2), diacylglycerols (DG) (16:0_18:0, 18:0_18:0), Lysophosphatidylcholine (LPC) (12:0, 20:5), PE (18:0_18:0), and TG (14:1_16:0_18:2, 15:0_17:0_19:0, 16:0_17:0_18:0, 19:0_19:0_19:0). Cluster analysis yielded three clusters of lipid profiles that were driven by just 10 lipid species (TGs and DGs). Cluster 1 had the highest levels of each lipid species and the highest prevalence of influenza A H3 infection (56%, n = 5) whereas cluster 3 had lower levels of each lipid species and the highest prevalence of rhinovirus (60%; n = 6). Using cluster 3 as the reference group, the crude odds of influenza A H3 infection compared to rhinovirus in cluster 1 was significantly (p = 0.047) higher (OR = 15.00 [95% CI: 1.03, 218.29]). After adjustment for confounders (smoking status and pulmonary comorbidities), the odds ratio (OR) became only marginally significant (p = 0.099), but the magnitude of the effect estimate was similar (OR = 16.00 [0.59, 433.03]).

Conclusions

In this study, human sputum lipid profiles were shown to be associated with distinct types of viral infection. Better understanding the relationship between respiratory infections of global importance and lipids contributes to advancing knowledge of pathogenesis of infections including identifying populations with increased susceptibility and developing effective therapeutics and biomarkers of health status.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02091-w.

Nonrespiratory sites of influenza-associated disease: mechanisms and experimental systems for continued study

The productive replication of human influenza viruses is almost exclusively restricted to cells in the respiratory tract. However, a key aspect of the host response to viral infection is the production of inflammatory cytokines and chemokines that are not similarly tissue restricted. As such, circulating inflammatory mediators, as well as the resulting activated immune cells, can induce damage throughout the body, particularly in individuals with underlying conditions. As a result, more holistic experimental approaches are required to fully understand the pathogenesis and scope of influenza virus-induced disease. This review summarizes what is known about some of the most well-appreciated nonrespiratory tract sites of influenza virus-induced disease, including neurological, cardiovascular, gastrointestinal, muscular and fetal developmental phenotypes. In the context of this discussion, we describe the in vivo experimental systems currently being used to study nonrespiratory symptoms. Finally, we highlight important future questions and potential models that can be used for a more complete understanding of influenza virus-induced disease.

A Review on Equine Influenza from a Human Influenza Perspective

Influenza A viruses (IAVs) have a main natural reservoir in wild birds. IAVs are highly contagious, continually evolve, and have a wide host range that includes various mammalian species including horses, pigs, and humans. Furthering our understanding of host-pathogen interactions and cross-species transmissions is therefore essential. This review focuses on what is known regarding equine influenza virus (EIV) virology, pathogenesis, immune responses, clinical aspects, epidemiology (including factors contributing to local, national, and international transmission), surveillance, and preventive measures such as vaccines. We compare EIV and human influenza viruses and discuss parallels that can be drawn between them. We highlight differences in evolutionary rates between EIV and human IAVs, their impact on antigenic drift, and vaccine strain updates. We also describe the approaches used for the control of equine influenza (EI), which originated from those used in the human field, including surveillance networks and virological analysis methods. Finally, as vaccination in both species remains the cornerstone of disease mitigation, vaccine technologies and vaccination strategies against influenza in horses and humans are compared and discussed.

Outbreak of Influenza and Other Respiratory Viruses in Hospitalized Patients Alongside the SARS-CoV-2 Pandemic

Influenza A and other respiratory viruses, circulate each winter and cause respiratory illness that can lead to severe complications in hospitalized patients. During the COVID-19 pandemic, only a few cases of respiratory viruses were detected in Israel. Our study applied RT-PCR to examine 13,674 samples collected from patients hospitalized with respiratory symptoms in 2019, 2020, and 2021 and the first half of the 2022 winter. A sharp increase in influenza A(H3N2) cases was observed in winter 2021-2022 as compared to 2020, followed by a sudden decrease in influenza cases after the detection of the SARS-CoV-2 omicron variant in Israel. Comparison of the area under the curve (AUC) of influenza infection rates during 7 consecutive winter seasons found that the minimal AUC between 2015 and 2020 was 281.1, while in 2021-2022, it was significantly lower (162.6 AUC; p = 0.0017), although the percentage of positive influenza cases was similar to those of previous years. The presented findings show how the dominance of influenza A(H3N2) abruptly ended upon circulation of the SARS-CoV-2 omicron variant. However, a post-COVID-19 influenza outbreak is possible, hence the planning of the next influenza vaccine is critical to ensure lower influenza-related hospitalization rates.

COVID-19 and H1N1-09: A Systematic Review of Two Pandemics with a Focus on the Lung at Autopsy

BACKGROUND

The purpose of this manuscript is to provide a comparative overview of the two global pandemics: the first on June 11th 2009 due to influenza A H1N1 (H1N1-09); the second and current pandemic caused by coronavirus 2019 (COVID-19) on March 11th 2020, focusing on how autopsy can contribute to the definition of cellular pathology, to clinical pathology and, more generally, to public health.

METHODS

A systematic literature search selection was conducted on PubMed database on June 5, 2021, with this search strategy: (COVID-19) AND (H1N1 influenza) showing 101 results. The following inclusion criteria were selected: English language; published in a scholarly peer-reviewed journal; full-length articles were further elected. To further refine the research was to focus on the type of manuscript: review, systematic review, and meta-analysis. A critical appraisal of the collected studies was conducted, analyzing titles and abstracts, excluding the following topics: treatment, public health measures and perception of the general population or healthcare personnel about their quality of life. According to these procedures, 54 eligible studies were included in the present review.

RESULTS

Histopathological findings play a key role in understanding the pathophysiological mechanisms of diseases and, thus possible therapeutic approaches. The evidence on the thrombo-inflammatory mechanism underlying COVID-19 is growing to a much greater magnitude than the diffuse alveolar damage in common with H1N1-09; our study appears to be in line with these results. The prevailing scientific thinking to explain the morbidity and mortality of COVID-19 patients is that it elicits an exuberant immune reaction characterized by dysregulated cytokine production, known as a "cytokine storm".

CONCLUSIONS

The histological and immunohistochemical pattern demonstrated similarities and differences between the infectious manifestations of the two pathogens, which justify empirical therapeutic approaches, in the first phase of the COVID-19 pandemic. Therefore, the previous pandemic should have taught us to promote a culture of clinical and forensic autopsies in order to provide timely evidence from integration among autopsy and clinical data for early adopting adequate therapies.

Neurotrophin Signaling Impairment by Viral Infections in the Central Nervous System

Neurotrophins, such as nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin 3 (NT-3), NT-4, and NT-5, are proteins involved in several important functions of the central nervous system. The activation of the signaling pathways of these neurotrophins, or even by their immature form, pro-neurotrophins, starts with their recognition by cellular receptors, such as tropomyosin receptor kinase (Trk) and 75 kD NT receptors (p75NTR). The Trk receptor is considered to have a high affinity for attachment to specific neurotrophins, while the p75NTR receptor has less affinity for attachment with neurotrophins. The correct functioning of these signaling pathways contributes to proper brain development, neuronal survival, and synaptic plasticity. Unbalanced levels of neurotrophins and pro-neurotrophins have been associated with neurological disorders, illustrating the importance of these molecules in the central nervous system. Furthermore, reports have indicated that viruses can alter the normal levels of neurotrophins by interfering with their signaling pathways. This work discusses the importance of neurotrophins in the central nervous system, their signaling pathways, and how viruses can affect them.

Azepanodipterocarpol is potential candidate for inhibits influenza H1N1 type among other lupane, oleanane, and dammarane A-ring amino-triterpenoids

A series of lupane-, oleanane- and dammarane-based triterpenoids with 3β-amino, A-ring azepano- and 3,4-seco-fragments has been synthesized and evaluated for antiviral activity against influenza A(H1N1) virus. It was found that azepanodipterocarpol 8 and 3β-amino-28-oxoallobetulin 11 showed antiviral activity with IC50 1.1 and 2.6 μg ml-1, and selectivity index of 19 and 10, respectively.

Investigating neutrophil cell death in TB pathogenesis

Background: Neutrophils are one of the major early role players in antimycobacterial immunity. Upon infection, neutrophils can undergo NETosis, a cell death characterized by release of neutrophil extracellular traps (NETs). The role of NETosis in TB progression remains poorly characterized. We aim to characterize mechanisms underlying NETosis during TB pathogenesis by identifying genes that drive the cell death, and to determine their potential as markers of disease progression in high-risk individuals. Finally, we intend to evaluate neutrophil associated genes as targets for host directed therapy to reduce pathological damage caused by NETosis. Methods: Quantitative PCR will be used to quantify expression of specific genes identified in the blood of individuals with active lung disease (n=30), compared to those from healthy (n=30) and latently infected individuals (LTBI) (n=30). In addition, temporal events associated with NETosis will be measured using live microscopy in a neutrophil in vitro model of Mycobacterium tuberculosis (Mtb) infection. Candidate genes found to be associated with NETosis will be targeted with pharmaceutical inhibitors. Conclusion: Genes associated with neutrophil mediated cell death may serve as potential biomarkers of pathological damage and disease progression, as well as targets for host-directed therapy.

Partial carbonization of quercetin boosts the antiviral activity against H1N1 influenza A virus

Inflenza A viruses (IAVs) are highly transmissible and pathogenic Orthomyxoviruses, which have led to worldwide outbreaks and seasonal pandemics of acute respiratory diseases, causing serious threats to public health. Currently used anti-influenza drugs may cause neurological side effects, and they are increasingly less effective against mutant strains. To help prevent the spread of IAVs, in this work, we have developed quercetin-derived carbonized nanogels (CNGs_Qur) that display potent viral inhibitory, antioxidative, and anti-inflammatory activities. The antiviral CNGs_Qur were synthesized by mild carbonization of quercetin (Qur), which successfully preserved their antioxidative and anti-inflammatory properties while also contributed enhanced properties, such as water solubility, viral binding, and biocompatibility. Antiviral assays of co-treatment, pre-treatment, and post-treatment indicate that CNGs_Qur interacts with the virion, revealing that the major antiviral mechanism resulting in the inhibition of the virus is by their attachment on the cell surface. Among them, the selectivity index (SI) of CNGs_Qur270 (>857.1) clearly indicated its great potential for clinical application in IAVs inhibition, which was much higher than that of pristine quercetin (63.7) and other clinical drugs (4-81). Compared with quercetin at the same dose, the combined effects of viral inhibition, antioxidative and anti-inflammatory activities impart the superior therapeutic effects of CNGs_Qur270 aerosol inhalation in the treatment of IAVs infection, as evidenced by a mouse model. These CNGs_Qur effectively prevent the spread of IAVs and suppress virus-induced inflammation while also exhibiting good in vivo biocompatibility. CNGs_Qur shows much promise as a clinical therapeutic agent against infection by IVAs.

Molecular Evolutionary Rate Predicts Intraspecific Genetic Polymorphism and Species-Specific Selection

It is unknown what determines genetic diversity and how genetic diversity is associated with various biological traits. In this work, we provide insight into these issues. By comparing genetic variation of 14,671 mammalian gene trees with thousands of individual human, chimpanzee, gorilla, mouse, and dog/wolf genomes, we found that intraspecific genetic diversity can be predicted by long-term molecular evolutionary rates rather than de novo mutation rates. This relationship was established during the early stage of mammalian evolution. Moreover, we developed a method to detect fluctuations of species-specific selection on genes based on the deviations of intraspecific genetic diversity predicted from long-term rates. We showed that the evolution of epithelial cells, rather than connective tissue, mainly contributed to morphological evolution of different species. For humans, evolution of the immune system and selective sweeps caused by infectious diseases are the most representative examples of adaptive evolution.

Mechanical control of innate immune responses against viral infection revealed in a human lung alveolus chip

Mechanical breathing motions have a fundamental function in lung development and disease, but little is known about how they contribute to host innate immunity. Here we use a human lung alveolus chip that experiences cyclic breathing-like deformations to investigate whether physical forces influence innate immune responses to viral infection. Influenza H3N2 infection of mechanically active chips induces a cascade of host responses including increased lung permeability, apoptosis, cell regeneration, cytokines production, and recruitment of circulating immune cells. Comparison with static chips reveals that breathing motions suppress viral replication by activating protective innate immune responses in epithelial and endothelial cells, which are mediated in part through activation of the mechanosensitive ion channel TRPV4 and signaling via receptor for advanced glycation end products (RAGE). RAGE inhibitors suppress cytokines induction, while TRPV4 inhibition attenuates both inflammation and viral burden, in infected chips with breathing motions. Therefore, TRPV4 and RAGE may serve as new targets for therapeutic intervention in patients infected with influenza and other potential pandemic viruses that cause life-threatening lung inflammation.

SARS-CoV-2 Spike Protein and Mouse Coronavirus Inhibit Biofilm Formation by Streptococcus pneumoniae and Staphylococcus aureus

The presence of co-infections or superinfections with bacterial pathogens in COVID-19 patients is associated with poor outcomes, including increased morbidity and mortality. We hypothesized that SARS-CoV-2 and its components interact with the biofilms generated by commensal bacteria, which may contribute to co-infections. This study employed crystal violet staining and particle-tracking microrheology to characterize the formation of biofilms by Streptococcus pneumoniae and Staphylococcus aureus that commonly cause secondary bacterial pneumonia. Microrheology analyses suggested that these biofilms were inhomogeneous soft solids, consistent with their dynamic characteristics. Biofilm formation by both bacteria was significantly inhibited by co-incubation with recombinant SARS-CoV-2 spike S1 subunit and both S1 + S2 subunits, but not with S2 extracellular domain nor nucleocapsid protein. Addition of spike S1 and S2 antibodies to spike protein could partially restore bacterial biofilm production. Furthermore, biofilm formation in vitro was also compromised by live murine hepatitis virus, a related beta-coronavirus. Supporting data from LC-MS-based proteomics of spike-biofilm interactions revealed differential expression of proteins involved in quorum sensing and biofilm maturation, such as the AI-2E family transporter and LuxS, a key enzyme for AI-2 biosynthesis. Our findings suggest that these opportunistic pathogens may egress from biofilms to resume a more virulent planktonic lifestyle during coronavirus infections. The dispersion of pathogens from biofilms may culminate in potentially severe secondary infections with poor prognosis. Further detailed investigations are warranted to establish bacterial biofilms as risk factors for secondary pneumonia in COVID-19 patients.

Oxidative Stress-Related Mechanisms in SARS-CoV-2 Infections

The COVID-19 pandemic caused relatively high mortality in patients, especially in those with concomitant diseases (i.e., diabetes, hypertension, and chronic obstructive pulmonary disease (COPD)). In most of aforementioned comorbidities, the oxidative stress appears to be an important player in their pathogenesis. The direct cause of death in critically ill patients with COVID-19 is still far from being elucidated. Although some preliminary data suggests that the lung vasculature injury and the loss of the functioning part of pulmonary alveolar population are crucial, the precise mechanism is still unclear. On the other hand, at least two classes of medications used with some clinical benefits in COVID-19 treatment seem to have a major influence on ROS (reactive oxygen species) and RNS (reactive nitrogen species) production. However, oxidative stress is one of the important mechanisms in the antiviral immune response and innate immunity. Therefore, it would be of interest to summarize the data regarding the oxidative stress in severe COVID-19. In this review, we discuss the role of oxidative and antioxidant mechanisms in severe COVID-19 based on available studies. We also present the role of ROS and RNS in other viral infections in humans and in animal models. Although reactive oxygen and nitrogen species play an important role in the innate antiviral immune response, in some situations, they might have a deleterious effect, e.g., in some coronaviral infections. The understanding of the redox mechanisms in severe COVID-19 disease may have an impact on its treatment.

RUNX1 inhibits the antiviral immune response against influenza A virus through attenuating type I interferon signaling

Background

Influenza A viruses (IAVs) are zoonotic, segmented negative-stranded RNA viruses. The rapid mutation of IAVs results in host immune response escape and antiviral drug and vaccine resistance. RUNX1 is a transcription factor that not only plays essential roles in hematopoiesis, but also functions as a regulator in inflammation. However, its role in the innate immunity to IAV infection has not been well studied.

Methods

To investigate the effects of RUNX1 on IAV infection and explore the mechanisms that RUNX1 uses during IAV infection. We infected the human alveolar epithelial cell line (A549) with influenza virus A/Puerto Rico/8/34 (H1N1) (PR8) and examined RUNX1 expression by Western blot and qRT-PCR. We also knocked down or overexpressed RUNX1 in A549 cells, then evaluated viral replication by Western blot, qRT-PCR, and viral titration.

Results

We found RUNX1 expression is induced by IAV H1N1 PR8 infection, but not by poly(I:C) treatment, in the human alveolar epithelial cell line A549. Knockdown of RUNX1 significantly inhibited IAV infection. Conversely, overexpression of RUNX1 efficiently promoted production of progeny viruses. Additionally, RUNX1 knockdown increased IFN-β and ISGs production while RUNX1 overexpression compromised IFN-β and ISGs production upon PR8 infection in A549 cells. We further showed that RUNX1 may attenuate the interferon signaling transduction by hampering the expression of IRF3 and STAT1 during IAV infection.

Conclusions

Taken together, we found RUNX1 attenuates type I interferon signaling to facilitate IAV infection in A549 cells.

Secondary infection with Streptococcus pneumoniae decreases influenza virus replication and is linked to severe disease

Secondary bacterial infection is a common complication in severe influenza virus infections. During the H1N1 pandemic of 2009, increased mortality was observed among healthy young adults due to secondary bacterial pneumonia, one of the most frequent bacterial species being Streptococcus pneumoniae (Spn). Previous studies in mice and ferrets have suggested a synergistic relationship between Spn and influenza viruses. In this study, the ferret model was used to examine whether secondary Spn infection (strains BHN97 and D39) influence replication and airborne transmission of the 2009 pandemic H1N1 virus (H1N1pdm09). Secondary infection with Spn after H1N1pdm09 infection consistently resulted in a significant decrease in viral titers in the ferret nasal washes. While secondary Spn infection appeared to negatively impact influenza virus replication, animals precolonized with Spn were equally susceptible to H1N1pdm09 airborne transmission. In line with previous work, ferrets with preceding H1N1pdm09 and secondary Spn infection had increased bacterial loads and more severe clinical symptoms as compared to animals infected with H1N1pdm09 or Spn alone. Interestingly, the donor animals that displayed the most severe clinical symptoms had reduced airborne transmission of H1N1pdm09. Based on these data, we propose an asymmetrical relationship between these two pathogens, rather than a synergistic one, since secondary bacterial infection enhances Spn colonization and pathogenesis but decreases viral titers.

Intermolecular Mechanism and Dynamic Investigation of Avian Influenza H7N9 Virus' Susceptibility to E119V-Substituted Peramivir-Neuraminidase Complex

The H7N9 virus attaches itself to the human cell receptor protein containing the polysaccharide that terminates with sialic acid. The mutation of neuraminidase at residue E119 has been explored experimentally. However, there is no adequate information on the substitution with E119V in peramivir at the intermolecular level. Therefore, a good knowledge of the interatomic interactions is a prerequisite in understanding its transmission mode and subsequent effective inhibitions of the sialic acid receptor cleavage by neuraminidase. Herein, we investigated the mechanism and dynamism on the susceptibility of the E119V mutation on the peramivir-neuraminidase complex relative to the wildtype complex at the intermolecular level. This study aims to investigate the impact of the 119V substitution on the neuraminidase-peramivir complex and unveil the residues responsible for the complex conformations. We employed molecular dynamic (MD) simulations and extensive post-MD analyses in the study. These extensive computational investigations were carried out on the wildtype and the E119V mutant complex of the protein for holistic insights in unveiling the effects of this mutation on the binding affinity and the conformational terrain of peramivir-neuraminidase E119V mutation. The calculated total binding energy (ΔGbind) for the peramivir wildtype is -49.09 ± 0.13 kcal/mol, while the E119V mutant is -58.55 ± 0.15 kcal/mol. The increase in binding energy (9.46 kcal/mol) is consistent with other post-MD analyses results, confirming that E119V substitution confers a higher degree of stability on the protein complex. This study promises to proffer contributory insight and additional knowledge that would enhance future drug designs and help in the fight targeted at controlling the avian influenza H7N9 virus. Therefore, we suggest that experimentalists collaborate with computational chemists for all investigations of this topic, as we have done in our previous studies.

Acute Respiratory Distress Syndrome Caused by Human Adenovirus in Adults: A Prospective Observational Study in Guangdong, China

Background

Viral causes of acute respiratory distress syndrome (ARDS) are mostly limited to influenza. However, adenovirus has been emerging as a cause of ARDS with a high mortality rate and described in adults are rare.

Methods

We conducted a prospective, single-center observational study of viral pneumonia with ARDS and confirmed adenovirus-associated ARDS in adults at our quaternary referral institution between March 2019 and June 2020. We prospectively analyzed clinical characteristics, laboratory test results, radiological characteristics, viral load from nasopharyngeal swabs and endotracheal aspirates, treatments, and outcomes for the study participants.

Results

The study enrolled 143 ARDS patients, including 47 patients with viral pneumonia-related ARDS, among which there were 14 adenovirus-associated ARDS patients, which accounted for 29.79% of the viral pneumonia-related ARDS cases. Among the adenovirus-associated ARDS patients, 78.57% were men with a mean age of 54.93 ± 19.04 years, younger than that of the non-adenovirus associated ARDS patients. Adenovirus-associated ARDS patients had no specific clinical characteristics, but they presented with decrease in the number of CD3+CD4+ T cells and higher serum creatinine during the early stage. The viral load and the positivity rate in the lower respiratory tract were higher than that of the upper respiratory tract in the patients with adenovirus-associated ARDS. All patients required invasive mechanical ventilation treatment. The average time from shortness of breath to the application of invasive ventilation was 24 h. Ten patients (71.43%) complicated by acute kidney injury, while 13 patients (71.43%) in the non-adenovirus associated ARDS group (P = 0.045). Additionally, 85.71% of the 14 adenovirus-associated ARDS patients survived. No significant differences were detected between the two groups regarding duration of ventilation, length of ICU stay and mortality.

Conclusion

Adenovirus infection is an important cause of virus-related ARDS. The positivity rate of adenovirus infection in lower respiratory tract secretions was higher than that in upper respiratory tract secretions in these patients. Age, lower CD3+CD4+ T cells, and high serum creatinine may be were associated with adenovirus induce ARDS in adults required mechanical ventilation. Early identification and intervention to prevent disease progression are essential for reducing the mortality rate in these patients.

Plasma Levels of Mid-Regional Proadrenomedullin Accurately Identify H1N1pdm09 Influenza Virus Patients with Risk of Intensive Care Admission and Mortality in the Emergency Department

Early identification of severe viral pneumonia in influenza virus A (H1N1pdm09) patients is extremely important for prompt admission to the ICU. The objective is to evaluate the usefulness of MR-proadrenomedullin (MR-proADM) compared to C reactive protein (CRP), procalcitonin (PCT), and ferritin in the prognosis of influenza A pneumonia. This prospective, observational, multicenter study included one hundred thirteen patients with confirmed influenza virus A (H1N1pdm09) admitted to an Emergency Department and ICUs of six hospitals in Spain. Measurements and Main Results: one-hundred thirteen patients with confirmed influenza virus A (H1N1pdm09) were enrolled. Seventy-five subjects (mortality 29.3%) with severe pneumonia caused by influenza A H1N1pdm09 virus (H1N1vIPN) were compared with 38 controls (CG).The median MR-proADM levels at hospital admission were 1.2 nmol/L (IQR (0.8–2.6) vs. 0.5 nmol/L (IQR 0.2–0.9) in the CG (p = 0.01), and PCT levels were 0.43 μg/L (IQR 0.2–1.2) in the H1N1vIPN group and 0.1 μg/L (IQR 0.1–0.2) in the CG (p < 0.01). CRP levels at admission were 15.5 mg/dL(IQR 9.2–24.9) in H1N1vIPN and 8.6 mg/dL(IQR 3–17.3) in the CG (p < 0.01). Ferritin levels at admission were 558.1 ng/mL(IQR 180–1880) in H1N1vIPN and 167.7 ng/mL(IQR 34.8–292.9) in the CG (p < 0.01). A breakpoint for hospital admission of MR-proADM of 1.1 nmol/L showed a sensitivity of 55% and a specificity of 90% (AUC-ROC0.822). Non-survivors showed higher MR-proADM levels: median of 2.5 nmol/L vs. 0.9 nmol/L among survivors (p < 0.01). PCT, CRP, and ferritin levels also showed significant differences in predicting mortality. The MR-proADM AUC-ROC for mortality was 0.853 (p < 0.01). In a Cox proportional hazards model, MR-proADM levels > 1.2 nmol/L at hospital admission were significant predictive factors for ICU and 90-day mortality (HR: 1.3). Conclusions: the initial MR-proADM, ferritin, CRP, and PCT levels effectively determine adverse outcomes and risk of ICU admission and mortality in patients with influenza virus pneumonia. MR-proADM has the highest potency for survival prediction.

Association between plasma glycocalyx component levels and poor prognosis in severe influenza type A (H1N1)

Influenza A virus infection causes a series of diseases, but the factors associated with disease severity are not fully understood. Disruption of the endothelial glycocalyx contributes to acute lung injury in sepsis, but has not been well studied in H1N1 influenza. We aim to determine whether the plasma glycocalyx components levels are predictive of disease severity in H1N1 influenza. This prospective observational study included 53 patients with influenza A (H1N1) during the influenza season, and 30 healthy controls in our hospital. Patients were grouped by severity and survival. We collected clinical data and blood samples at admission. Inflammatory factors (tumor necrosis factor-α, interleukin-6, interleukin-10) and endothelial glycocalyx components (syndecan-1, hyaluronan, heparan sulfate) were measured. The plasma levels of syndecan-1, hyaluronan, and heparan sulfate were significantly higher in patients with severe influenza A (H1N1) than in mild cases. Syndecan-1 and hyaluronan were positively correlated with disease severity, which was indicated by the APACHE II and SOFA scores and lactate levels, and negatively correlated with albumin levels. At a cutoff point ≥ 173.9 ng/mL, syndecan-1 had a 81.3% sensitivity and 70.3% specificity for predicting of 28-day mortality. Kaplan–Meier analysis demonstrated a strong association between syndecan-1 levels and 28-day mortality (log-rank 11.04, P = 0.001). Elevated plasma levels of syndecan-1 has a potential role in systemic organ dysfunction and may be indicative of disease severity in patients with influenza A (H1N1).

Atypical skin manifestation in severe acute chikungunya infection in a pregnant woman: a case report

INTRODUCTION

Patients with chikungunya virus infection commonly present with fever, skin rash, and severe joint pain. The vesiculobullous rash is rare in adults but common in infants. In addition, septic shock and acute respiratory distress syndrome are rare complications of atypical and severe acute chikungunya infection.

CASE PRESENTATION

We report the presence of an 18-year-old Thai female, at 31 weeks gestation, with fever, maculopapular rash, and polyarthritis. The rash later progressed to a vesiculobullous pattern, and she developed septic shock and acute respiratory distress syndrome. Skin biopsy and blood were positive for chikungunya virus RNA. The patient was intubated with a mechanical ventilator and subsequently fully recovered.

CONCLUSION

Atypical skin manifestation and severe acute disease is likely due to immune response attenuation in pregnancy. The possibility of progression to severe or atypical disease in pregnant women suffering chikungunya should always be considered.

Impact of influenza infection on the short- and long-term health of patients with chronic obstructive pulmonary disease

BACKGROUND

Influenza is a common cause of acute respiratory infection that leads to exacerbation of underlying chronic obstructive pulmonary disease (COPD). To elucidate the short- and long-term effects of influenza in patients with COPD, we examined health care resource utilization (HRU) and costs up to 13 months following influenza infection.

METHODS

We conducted a retrospective cohort study using U.S. insurance claims data from MarketScan. Patients with an influenza diagnosis during the 2012-2014 influenza seasons and continuous enrollment in a health plan from 12 months before to 13 months after the index influenza diagnosis were identified and propensity score-matched 1:5 to controls without evidence of influenza. COPD- and pneumonia-related outcomes were assessed over 13 months following influenza diagnosis.

RESULTS

COPD-associated outcomes after diagnosis were significantly worse in patients with influenza (n = 7,087) vs. controls (n = 35,435) during the first month (exacerbation: 16.1 vs. 3.4%; outpatient visits: 57.1 vs. 35.2%; emergency department (ED) visits: 10.5 vs. 1.8%; and inpatient visits: 5.6 vs. 0.7%) and months 2-13 (exacerbation: 25.1 vs. 21.1%; outpatient visits: 86.1 vs. 85.8%; ED visits: 20.0 vs. 15.7%; and inpatient visits: 6.5 vs. 5.3%). COPD- and pneumonia-associated costs for months 1 and 2-13 were higher in patients with influenza.

LIMITATIONS

The study was subject to a residual imbalance between cohorts despite propensity score matching. The use of diagnostic codes to select patients and identify complications could introduce inaccuracies in estimating events.

CONCLUSIONS

HRU and costs were higher in COPD patients with influenza during the first month and over the entire year following infection. This suggests influenza has an impact on respiratory health in patients with COPD that lasts beyond the acute infection.

Rational Design of Copper-Selenium Nanoclusters Cures Sepsis by Consuming Endogenous H2S to Trigger Photothermal Therapy and ROS Burst

The treatment of sepsis caused by bacterial infection is still a huge clinical challenge, which could attribute to the endogenous hydrogen sulfide (H2S) of sepsis, as its existence can promote...

Morbidity of late-season influenza during pregnancy

BACKGROUND

In the Northern Hemisphere, influenza season typically starts in December and lasts through March. Pregnant people are at increased risk for influenza-related morbidity and mortality. Potentially, new viral strains or reduced provider suspicion leading to delayed diagnosis of late-season influenza could result in an increased risk of severe infection.

OBJECTIVE

This study aimed to assess the incidence and morbidity associated with late-season influenza in pregnancy, compared with influenza in other seasons.

STUDY DESIGN

This was a retrospective cohort study using the 2007-2018 National Inpatient Sample. Pregnant patients with discharge diagnosis codes consistent with influenza infection were compared on the basis of hospital admission quarter (quarter 1: October to December; quarter 2: January to March; quarter 3: April to June; quarter 4: July to September), with quarter 3 defined as "late-season." The primary outcome was the severe maternal morbidity composite defined by the Centers for Disease Control and Prevention. The secondary outcomes included sepsis, shock, acute renal failure, acute heart failure, temporary tracheostomy, and invasive mechanical ventilation. Associations between outcomes and quarter of infection were adjusted for age, hospitalization type (antepartum, delivery, or postpartum), and comorbid conditions using relative risk regression, weighted to reflect the National Inpatient Sample design.

RESULTS

Of 7355 hospitalizations, corresponding to a weighted national estimate of 36,042, 2266 (30.8%) occurred in quarter 1, 4051 (55.0%) in quarter 2, 633 (8.6%) in quarter 3, and 405 (5.5%) in quarter 4. A nonsignificant trend toward higher rates of severe maternal morbidity was seen in the "late-season" compared with other quarters (13.9% [quarter 3] vs 10.5% [quarter 1] vs 12.1% [quarter 2] vs 13.6% [quarter 4]; P=.07). Moreover, sepsis was more common in patients with late-season influenza (8.0% [quarter 3] vs 4.8% [quarter 1] vs 5.8% [quarter 2] vs 5.9% [quarter 4]; P=.03). In the adjusted analyses, patients with late-season influenza had a 1.34 (95% confidence interval, 1.01-1.78) higher risk of severe maternal morbidity and 1.57 (95% confidence interval, 1.06-2.32) higher risk of sepsis than patients with influenza in quarter 1.

CONCLUSION

Influenza infection between April and June, that is, late-season influenza, is associated with a higher risk of severe maternal morbidity and sepsis in pregnant patients. Obstetrical providers must continue to have awareness and suspicion for influenza infection during these months.

Place des virus respiratoires dans les pneumonies aiguës communautaires de l'adulte : quels changements depuis la Covid-19 ?

L’émergence du SARS-CoV-2 a renforcé l'intérêt pour la place des virus respiratoires, dans les pneumonies aiguës communautaires, en mettant en exergue de nombreux points encore mal connus tels que la part des infections asymptomatiques, les interactions entre virus respiratoires et pathogènes non viraux, leurs périodes d'incubation, leur pathogénicité ou encore la durée d'excrétion variable.

La présentation clinique et radiologique des pneumonies aiguës communautaires ne permet pas toujours de distinguer l'origine virale de l'origine bactérienne.

L'absence de réelle conséquence thérapeutique semble un frein à l'utilisation des PCR multiplex dans la pratique quotidienne. Toutefois, l'amélioration en termes de délai de rendu des résultats et du nombre de pathogènes inclus dans les panels, ainsi que l'accumulation récente de données épidémiologiques et cliniques, devraient aider à rationaliser l'utilisation de ces tests, faciliter l'interprétation de leurs résultats et guider l'utilisation des molécules antivirales en développement.