Type I and type III interferons: From basic biology and genetics to clinical development for COVID-19 and beyond.

Type I and type III interferons (IFNs) constitute a key antiviral defense systems of the body, inducing viral resistance to cells and mediating diverse innate and adaptive immune functions. Defective type I and type III IFN responses have recently emerged as the 'Achilles heel' in COVID-19, with such patients developing severe disease and exhibiting a high risk for critical pneumonia and death. Here, we review the biology of type I and type III IFNs, their similarities and important functional differences, and their roles in SARS-CoV-2 infection. We also appraise the various mechanisms proposed to drive defective IFN responses in COVID-19 with particular emphasis to the ability of SARS-CoV-2 to suppress IFN production and activities, the genetic factors involved and the presence of autoantibodies neutralizing IFNs and accounting for a large proportion of individuals with severe COVID-19. Finally, we discuss the long history of the type I IFN therapeutics for the treatment of viral diseases, cancer and multiple sclerosis, the various efforts to use them in respiratory infections, and the newly emerging type III IFN therapeutics, with emphasis to the more recent studies on COVID-19 and their potential use as broad spectrum antivirals for future epidemics or pandemics.

Clara cell 10 (CC10) protein attenuates allergic airway inflammation by modulating lung dendritic cell functions.

Allergic asthma is a complex inflammatory disorder predominantly orchestrated by T helper 2 (Th2) lymphocytes. The anti-inflammatory protein Clara Cell 10-kDa (CC10), also known as secretoglobin family 1A member 1 (SCGB1A1), shows promise in modulating respiratory diseases. However, its precise role in asthma remains unclear. This study examines the potential of CC10 to suppress allergic asthma inflammation, specifically assessing its regulatory effects on Th2 cell responses and dendritic cells (DCs). Lower CC10 levels in asthma were observed and correlated with increased IgE and lymphocytes. Cc10-/- mice exhibited exacerbated allergic airway inflammation marked by increased inflammatory cell infiltration, Th2 cytokines, serum antigen-specific IgE levels, and airway hyperresponsiveness (AHR) in house dust mite (HDM)-induced models. Conversely, recombinant CC10 significantly attenuated these inflammatory responses. Intriguingly, CC10 did not directly inhibit Th cell activation but significantly downregulated the population of CD11b+CD103- DCs subsets in lungs of asthmatic mice and modulated the immune activation functions of DCs through NF-κB signaling pathway. The mixed lymphocyte response assay revealed that DCs mediated the suppressive effect of CC10 on Th2 cell responses. Collectively, CC10 profoundly mitigates Th2-type allergic inflammation in asthma by modulating lung DC phenotype and functions, highlighting its therapeutic potential for inflammatory airway conditions and other related immunological disorders.

Diagnostic Potential of Oscillometry: A Population-based Approach.

Rationale: Respiratory resistance (Rrs) and reactance (Xrs) as measured by oscillometry and their intrabreath changes have emerged as sensitive parameters for detecting early pathological impairments during tidal breathing. Objectives: This study evaluates the prevalence and association of abnormal oscillometry parameters with respiratory symptoms and respiratory diseases in a general adult population. Methods: A total of 7,560 subjects in the Austrian LEAD (Lung, hEart, sociAl, boDy) Study with oscillometry measurements (computed with the Resmon Pro FULL; Restech Srl) were included in this study. The presence of respiratory symptoms and doctor-diagnosed respiratory diseases was assessed using an interview-based questionnaire. Rrs and Xrs at 5 Hz, their inspiratory and expiratory components, the area above the Xrs curve, and the presence of tidal expiratory flow limitation were analyzed. Normality ranges for oscillometry parameters were defined. Measurements and Main Results: The overall prevalence of abnormal oscillometry parameters was 20%. The incidence of abnormal oscillometry increased in the presence of symptoms or diagnoses: 17% (16-18%) versus 27% (25-29%), P < 0.0001. All abnormal oscillometry parameters except Rrs at 5 Hz were significantly associated with respiratory symptoms/diseases. Significant associations were found, even in subjects with normal spirometry, with abnormal oscillometry incidence rates increasing by 6% (4-8%; P < 0.0001) in subjects with symptoms or diagnoses. Conclusions: Abnormal oscillometry parameters are present in one-fifth of this adult population and are significantly associated with respiratory symptoms and disease. Our findings underscore the potential of oscillometry as a tool for detecting and evaluating respiratory impairments, even in individuals with normal spirometry.

The oral microbiome of newly diagnosed tuberculosis patients; a pilot study.

BACKGROUND: Changes in oral microbiota composition (dysbiosis) have long been known to play a key role in the pathogenesis of oral and systemic diseases including respiratory diseases. However, till now, no study has assessed changes in oral microbiota following tuberculosis (TB) infection in humans. AIMS: This is the first study of its kind that aimed to investigate oral microbial dysbiosis in newly diagnosed, treatment naïve, TB patients. METHODS: Oral swab samples were collected from newly diagnosed TB patients (n = 20) and age, gender and ethnicity matched healthy controls (n = 10). DNA was extracted and microbiota analyzed by sequencing the hypervariable (V3-V4) region of the bacterial 16S rRNA gene using Illumina MiSeq platform. Bioinformatics and statistical analyses were performed using QIIME and R. RESULTS: Bacterial richness, diversity and community composition were significantly different between TB patients and healthy controls. The two groups also exhibit differential abundance at phylum, class, genus and species levels. LEfSe analysis revealed enrichment (LDA scores (log10) >2, P < 0.05) of Firmicutes (especially Streptococcus) and Actinobacteriota (especially Rothia) in TB patients relative to healthy controls. Gene function prediction analysis showed upregulation of metabolic pathways related to carbohydrates (butanoate, galactose) and fatty acids metabolism, antibiotics biosynthesis, proteosome and immune system signaling. CONCLUSION: These observations suggest significant variations in diversity, relative abundance and functional potential of oral microbiota of TB patients compared to healthy controls thereby suggesting potential role of oral bacterial dysbiosis in TB pathogenesis. However, longitudinal studies using powerful metagenomic and transcriptomic approaches are crucial to more fully understand and confrim these findings.

Research progress of KL-6 in respiratory system diseases.

This article comprehensively elucidates the discovery of Krebs von den Lungen-6 (KL-6), its structural features, functional mechanisms, and the current research status in various respiratory system diseases. Discovered in 1985, KL-6 was initially considered a tumor marker, but its elevated levels in interstitial lung disease (ILD) led to its recognition as a relevant serum marker for ILD. KL-6 is primarily produced by type 2 alveolar epithelial cell regeneration. Over the past 30 years since the discovery of KL-6, the number of related research papers has steadily increased annually. Following the coronavirus disease 2019 (COVID-19) pandemic, there has been a sudden surge in relevant literature. Despite KL-6's potential as a biomarker, its value in the diagnosis, treatment, and prognosis varies across different respiratory diseases, including ILD, idiopathic pulmonary fibrosis (IPF), COVID-19, and lung cancer. Therefore, as an important serum biomarker in respiratory system diseases, the value of KL-6 still requires further investigation.

Advancement in the development of mRNA-based vaccines for respiratory viruses.

Acute respiratory infections are the leading cause of death and illness in children under 5 years old and represent a significant burden in older adults. Primarily caused by viruses infecting the lower respiratory tract, symptoms include cough, congestion, and low-grade fever, potentially leading to bronchiolitis and pneumonia. Messenger ribonucleic acid (mRNA)-based vaccines are biopharmaceutical formulations that employ mRNA molecules to induce specific immune responses, facilitating the expression of viral or bacterial antigens and promoting immunization against infectious diseases. Notably, this technology had significant relevance during the COVID-19 pandemic, as these formulations helped to limit SARS-CoV-2 virus infections, hospitalizations, and deaths. Importantly, mRNA vaccines promise to be implemented as new alternatives for fighting other respiratory viruses, such as influenza, human respiratory syncytial virus, and human metapneumovirus. This review article analyzes mRNA-based vaccines' main contributions, perspectives, challenges, and implications against respiratory viruses.

Vaccine Effectiveness against SARS-CoV-2 among Household Contacts during Omicron BA.2-Dominant Period, Japan.

We calculated attack rates for household contacts of COVID-19 patients during the SARS-CoV-2 Omicron BA.2-dominant period in Japan. Attack rates among household contacts without recent (<3 months) vaccination was lower for contacts of index patients with complete vaccination than for contacts of index patients without complete vaccination, demonstrating indirect vaccine effectiveness.

The role of vasculature and angiogenesis in respiratory diseases.

In European countries, nearly 10% of all hospital admissions are related to respiratory diseases, mainly chronic life-threatening diseases such as COPD, pulmonary hypertension, IPF or lung cancer. The contribution of blood vessels and angiogenesis to lung regeneration, remodeling and disease progression has been increasingly appreciated. The vascular supply of the lung shows the peculiarity of dual perfusion of the pulmonary circulation (vasa publica), which maintains a functional blood-gas barrier, and the bronchial circulation (vasa privata), which reveals a profiled capacity for angiogenesis (namely intussusceptive and sprouting angiogenesis) and alveolar-vascular remodeling by the recruitment of endothelial precursor cells. The aim of this review is to outline the importance of vascular remodeling and angiogenesis in a variety of non-neoplastic and neoplastic acute and chronic respiratory diseases such as lung infection, COPD, lung fibrosis, pulmonary hypertension and lung cancer.

The role of hydrogen sulfide regulation of ferroptosis in different diseases.

Ferroptosis is a programmed cell death that relies on iron and lipid peroxidation. It differs from other forms of programmed cell death such as necrosis, apoptosis and autophagy. More and more evidence indicates that ferroptosis participates in many types of diseases, such as neurodegenerative diseases, ischemia-reperfusion injury, cardiovascular diseases and so on. Hence, clarifying the role and mechanism of ferroptosis in diseases is of great significance for further understanding the pathogenesis and treatment of some diseases. Hydrogen sulfide (H2S) is a colorless and flammable gas with the smell of rotten eggs. Many years ago, H2S was considered as a toxic gas. however, in recent years, increasing evidence indicates that it is the third important gas signaling molecule after nitric oxide and carbon monoxide. H2S has various physiological and pathological functions such as antioxidant stress, anti-inflammatory, anti-apoptotic and anti-tumor, and can participate in various diseases. It has been reported that H2S regulation of ferroptosis plays an important role in many types of diseases, however, the related mechanisms are not fully clear. In this review, we reviewed the recent literature about the role of H2S regulation of ferroptosis in diseases, and analyzed the relevant mechanisms, hoping to provide references for future in-depth researches.

COVID-19 Vaccination in Patients with Inborn Errors of Immunity Reduces Hospitalization and Critical Care Needs Related to COVID-19: a USIDNET Report.

BACKGROUND: The CDC and ACIP recommend COVID-19 vaccination for patients with inborn errors of immunity (IEI). Not much is known about vaccine safety in IEI, and whether vaccination attenuates infection severity in IEI. OBJECTIVE: To estimate COVID-19 vaccination safety and examine effect on outcomes in patients with IEI. METHODS: We built a secure registry database in conjunction with the US Immunodeficiency Network to examine vaccination frequency and indicators of safety and effectiveness in IEI patients. The registry opened on January 1, 2022, and closed on August 19, 2022. RESULTS: Physicians entered data on 1245 patients from 24 countries. The most common diagnoses were antibody deficiencies (63.7%). At least one COVID-19 vaccine was administered to 806 patients (64.7%), and 216 patients received vaccination prior to the development of COVID-19. The most common vaccines administered were mRNA-based (84.0%). Seventeen patients were reported to seek outpatient clinic or emergency room care for a vaccine-related complication, and one patient was hospitalized for symptomatic anemia. Eight hundred twenty-three patients (66.1%) experienced COVID-19 infection. Of these, 156 patients required hospitalization (19.0%), 47 required ICU care (5.7%), and 28 died (3.4%). Rates of hospitalization (9.3% versus 24.4%, p < 0.001), ICU admission (2.8% versus 7.6%, p = 0.013), and death (2.3% versus 4.3%, p = 0.202) in patients who had COVID-19 were lower in patients who received vaccination prior to infection. In adjusted logistic regression analysis, not having at least one COVID-19 vaccine significantly increased the odds of hospitalization and ICU admission. CONCLUSION: Vaccination for COVID-19 in the IEI population appears safe and attenuates COVID-19 severity.

Genetic perturbation of IL-6 receptor signaling pathway and risk of multiple respiratory diseases.

Dysregulation of inflammation can lead to multiple chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and asthma. Interleukin-6 (IL6) is crucial in regulating the inflammatory cascade, but the causal link between IL6 signaling downregulation and respiratory diseases risk is unclear. This study uses Mendelian randomization to examine the effects of IL6R blockade on respiratory diseases. Analyzing data from 522,681 Europeans, 26 genetic variants were obtained to mimic IL6R inhibition. Our findings show that IL6R blockade significantly reduces the risk of COPD (OR = 0.71, 95% CI = 0.60-9.84) and asthma (OR = 0.82, 95% CI = 0.74-0.90), with protective trends for bronchitis, pulmonary embolism, and lung cancer. Results were consistent across methods, with no significant heterogeneity or pleiotropy. These insights suggest IL6R downregulation as a potential therapeutic target for respiratory diseases, meriting further clinical investigation.

Association of dietary flavonoid intakes with prevalence of chronic respiratory diseases in adults.

BACKGROUND AND AIMS: Flavonoids are a class of secondary plant metabolites that have been shown to have multiple health benefits, including antioxidant and anti-inflammatory. This study was to explore the association between dietary flavonoid consumption and the prevalence of chronic respiratory diseases (CRDs) in adults. METHODS AND RESULTS: The six main types of flavonoids, including isoflavones, anthocyanidins, flavan-3-ols, flavanones, flavones, and flavonols, were obtained from the National Health and Nutrition Examination Survey (NHANES) 2007-2010 and 2017-2018 by the two 24-h recall interviews. The prevalence of CRDs, including asthma, emphysema, and chronic bronchitis, was determined through a self-administered questionnaire. The analysis included 15,753 participants aged 18 years or older who had completed a diet history interview. After adjustment for potential confounders, the inverse link was found with total flavonoids, anthocyanidins, flavanones, and flavones, with an OR (95%CI) of 0.86 (0.75-0.98), 0.84 (0.72-0.97), 0.80(0.69-0.92), and 0.85(0.73-0.98) for the highest group compared to the lowest group. WQS regression revealed that the mixture of flavonoids was negatively linked with the prevalence of CRDs (OR = 0.88 [0.82-0.95], P < 0.01), and the largest effect was mainly from flavanones (weight = 0.41). In addition, we found that flavonoid intake was negatively linked with inflammatory markers, and systemic inflammation significantly mediated the associations of flavonoids with CRDs, with a mediation rate of 12.64% for CRP (P < 0.01). CONCLUSION: Higher flavonoid intake was related with a lower prevalence of CRDs in adults, and this relationship may be mediated through systemic inflammation.

Gastroesophageal reflux disease and the risk of respiratory diseases: a Mendelian randomization study.

BACKGROUND: Observational studies have suggested a suspected association between gastroesophageal reflux disease (GERD) and respiratory diseases, but the causality remains equivocal. The goal of this study was to evaluate the causal role of GERD in respiratory diseases by employing Mendelian randomization (MR) studies. METHODS: We conducted Mendelian randomization analysis based on summary data of genome-wide association studies (GWASs) and three MR statistical techniques (inverse variance weighted, weighted median and MR-Egger) were employed to assess the probable causal relationship between GERD and the risk of respiratory diseases. Sensitivity analysis was also carried out to ensure more trustworthy results, which involves examining the heterogeneity, pleiotropy and leave-one-SNP-out method. We also identified 33 relevant genes and explored their distribution in 26 normal tissues. RESULTS: In the analysis, for every unit increase in developing GERD, the odds ratio for developing COPD, bronchitis, pneumonia, lung cancer and pulmonary embolism rose by 72% (ORIVW = 1.72, 95% CI 1.50; 1.99), 19% (ORIVW = 1.19, 95% CI 1.11; 1.28), 16% (ORIVW = 1.16, 95% CI 1.07; 1.26), 0. 3% (ORIVW = 1.003, 95% CI 1.0012; 1.0043) and 33% (ORIVW = 1.33, 95% CI 1.12; 1.58), respectively, in comparison with non-GERD cases. In addition, neither heterogeneity nor pleiotropy was found in the study. This study also found that gene expression was higher in the central nervous system and brain tissue than in other normal tissues. CONCLUSIONS: This study provided evidence that people who developed GERD had a higher risk of developing COPD, bronchitis, pneumonia, lung cancer and pulmonary embolism. Our research suggests physicians to give effective treatments for GERD on respiratory diseases. By exploring the gene expression, our study may also help to reveal the role played by the central nervous system and brain tissue in developing respiratory diseases caused by GERD.

Therapeutic potential of mesenchymal stem cell-derived exosomes for allergic airway inflammation.

Due to their immunomodulatory capacities, mesenchymal stem cells (MSCs) have been extensively used as therapeutic approaches in cell-based therapy for various inflammatory diseases. Several lines of studies have shown that the most beneficial effects of MSCs are associated with MSC-derived exosomes. Exosomes are nanoscale extracellular vesicles that contain important biomolecules such as RNA, microRNAs (miRNAs), DNA, growth factors, enzymes, chemokines, and cytokines that regulate immune cell functions and parenchymal cell survival. Recently, exosomes, especially MSC-derived exosomes, have been shown to have protective effects in allergic airway inflammation. This review focused on the immune-regulatory potential of MSC-derived exosomes as nanoscale delivery systems in the treatment of allergic airway inflammation.

The causality between systemic inflammatory regulators and chronic respiratory diseases: A bidirectional Mendelian-randomization study.

INTRODUCTION: Accumulative evidence suggests the associations between systemic inflammatory regulators and chronic respiratory diseases (CRDs). However, the intrinsic causation remains implicit. Therefore, this study aimed to examine causative associations by mendelian randomization (MR) and to identify valuable active factors. METHODS: Based on data from the GWAS database, we performed MR analyses of 41 serum cytokines from 8,293 Finnish and European descent cohorts from GBMI and UKBB for five major CRDs. We mainly applied inverse variance weighted regression, supplemented by MR-Egger regression, weighted median, maximum likelihood, weighted mode, and simple mode algorithms. Moreover, sensitivity analyses were conducted using Cochrane's Q test, MR-Egger intercept, MR-PRESSO Global test and MR-Steiger filtering. Eventually, the consistency of MR results was assessed by leave-one-out. RESULTS: Our results suggest that 12 genetically predicted systemic inflammatory regulators probably participate in the progression of CRDs, including four risk factors (IL-1RA, IL-4, MIP-1A, PDGF-BB) and one protective factor (IL-6) in IPF, two protective factors (SCF, SDF-1A) in COPD, and two protective factors (SCF, SDF-1A) in asthma, two protective factors (GROA, IL-2RA) were also included in asthma, whereas only one factor (HGF) was protective against bronchiectasis. Additionally, two protective factors (FGF-BASIC, G-CSF) were identified in sarcoidosis. Sensitivity analyses showed no horizontal pleiotropy and significant heterogeneity. Finally, based on the findings of inverse MR analysis, no inverse causal association was uncovered, confirming the robustness of results. CONCLUSION: Our study unearths potential associations between systemic inflammatory modulators and common CRDs, providing new insights for inflammation-mediated CRD prevention and therapeutic approaches.

The role of IL-2 cytokine family in asthma.

BACKGROUND: The interleukin-2 (IL-2) family of cytokines, including IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21, are pivotal regulators of the immune response, impacting both innate and adaptive immunity. Understanding their molecular characteristics, receptor interactions, and signalling pathways is essential for elucidating their roles in health and disease. OBJECTIVES: This review provides a comprehensive overview of the IL-2 family of cytokines, highlighting their molecular biology, receptor interactions, and signalling mechanisms. Furthermore, it explores the involvement of IL-2 family cytokines in the pathogenesis of chronic respiratory diseases, with a specific focus on chronic obstructive pulmonary disease (COPD) and asthma. METHODS: A thorough literature review was conducted to gather insights into the molecular biology, receptor interactions, and signalling pathways of IL-2 family cytokines. Additionally, studies investigating the roles of these cytokines in chronic respiratory diseases, particularly COPD and asthma, were analysed to discern their implications in wider pathophysiology of disease. RESULTS: IL-2 family cytokines exert pleiotropic effects on immune cells, modulating cellular proliferation, differentiation, and survival. Dysregulation of IL-2 family cytokines has been implicated in the pathogenesis of chronic respiratory illnesses, including COPD and asthma. Elevated levels of IL-2 and IL-9 have been associated with disease severity in COPD, while IL-4 and IL-9 play crucial roles in asthma pathogenesis by promoting airway inflammation and remodelling. CONCLUSION: Understanding the intricate roles of IL-2 family cytokines in chronic respiratory diseases provides valuable insights into potential therapeutic targets for these conditions. Targeting specific cytokines or their receptors may offer novel treatment modalities to attenuate disease progression and improve clinical outcomes in patients with COPD and asthma.

Improved pediatric ICU mortality prediction for respiratory diseases: machine learning and data subdivision insights.

The growing concern of pediatric mortality demands heightened preparedness in clinical settings, especially within intensive care units (ICUs). As respiratory-related admissions account for a substantial portion of pediatric illnesses, there is a pressing need to predict ICU mortality in these cases. This study based on data from 1188 patients, addresses this imperative using machine learning techniques and investigating different class balancing methods for pediatric ICU mortality prediction. This study employs the publicly accessible "Paediatric Intensive Care database" to train, validate, and test a machine learning model for predicting pediatric patient mortality. Features were ranked using three machine learning feature selection techniques, namely Random Forest, Extra Trees, and XGBoost, resulting in the selection of 16 critical features from a total of 105 features. Ten machine learning models and ensemble techniques are used to make accurate mortality predictions. To tackle the inherent class imbalance in the dataset, we applied a unique data partitioning technique to enhance the model's alignment with the data distribution. The CatBoost machine learning model achieved an area under the curve (AUC) of 72.22%, while the stacking ensemble model yielded an AUC of 60.59% for mortality prediction. The proposed subdivision technique, on the other hand, provides a significant improvement in performance metrics, with an AUC of 85.2% and an accuracy of 89.32%. These findings emphasize the potential of machine learning in enhancing pediatric mortality prediction and inform strategies for improved ICU readiness.

Demographic and geographical trends in chronic lower respiratory diseases mortality in the United States, 1999 to 2020.

Chronic lower respiratory disease (CLRD) related mortality has decreased in the United States due to increasing awareness in the general population and advancing preventative efforts, diagnostic measures, and treatment. However, demographic and regional differences still persist throughout the United States. In this study, we analyzed the temporal trends of demographic and geographical differences in CLRD-related mortality. Data was extracted from the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (CDC WONDER) database. Using this data, age-adjusted mortality rates per 100,000 people (AAMR), annual percentage change (APC), and average annual percentage changes with 95% confidence intervals (CIs) were assessed. The Joinpoint Regression Program was used to determine mortality trends between 1999 and 2020 based on demographic and regional groups.During this study period, there were 3,064,049 CLRD-related deaths, with most demographics and regional areas showing an overall decreasing trend. However, higher mortality rates were seen in the non-Hispanic White population and rural areas. Interestingly, mortality rates witnessed a decreasing trend for males throughout the study duration compared to females, who only began to show decreases in mortality during the latter half of the 2010s. Using these results, one can target efforts and build policies to improve CLRD-related mortality and reduce disparities in the coming decades.

Exploring the Association of Metabolic Syndrome with In-Hospital Survival of Older Patients Hospitalized with COVID-19: Beyond Chronological Age.

BACKGROUND: Despite the variability and complexity of geriatric conditions, few COVID-19 reports of clinical characteristic prognostication provide data specific to oldest-old adults (over age 85), and instead generally report broadly as 65 and older. OBJECTIVE: To examine metabolic syndrome criteria in adults across 25 hospitals with variation in chronological age. DESIGN AND PARTICIPANTS: This cohort study examined 39,564 hospitalizations of patients aged 18 or older with COVID-19 who received inpatient care between March 13, 2020, and February 28, 2022. EXPOSURE: ICU admission and/or in-hospital mortality. MAIN MEASURES: Metabolic syndrome criteria and patient demographics were examined as risk factors. The main outcomes were admission to ICU and hospital mortality. KEY RESULTS: Oldest old patients (≥ 85 years) hospitalized with COVID-19 accounted for 7.0% (2758/39,564) of all adult hospitalizations. They had shorter ICU length of stay, similar overall hospitalization duration, and higher rates of discharge destinations providing healthcare services (i.e., home health, skilled nursing facility) compared to independent care. Chronic conditions varied by age group, with lower proportions of diabetes and uncontrolled diabetes in the oldest-old cohort compared with young-old (65-74 years) and middle-old (75-84 years) groups. Evaluations of the effect of metabolic syndrome and patient demographics (i.e., age, sex, race) on ICU admission demonstrate minimal change in the magnitude of effect for metabolic syndrome on ICU admission across the different models. CONCLUSIONS: Metabolic syndrome measures are important individual predictors of COVID-19 outcomes. Building on prior examinations that metabolic syndrome is associated with death and ARDS across all ages, this analysis supports that metabolic syndrome criteria may be more relevant than chronological age as risk factors for poor outcomes attributed to COVID-19.

Exosome-mediated regulation of inflammatory pathway during respiratory viral disease.

Viruses have developed many mechanisms by which they can stimulate or inhibit inflammation and cause various diseases, including viral respiratory diseases that kill many people every year. One of the mechanisms that viruses use to induce or inhibit inflammation is exosomes. Exosomes are small membrane nanovesicles (30-150 nm) released from cells that contain proteins, DNA, and coding and non-coding RNA species. They are a group of extracellular vesicles that cells can take up to produce and mediate communication. Intercellular effect exosomes can deliver a broad confine of biological molecules, containing nucleic acids, proteins, and lipids, to the target cell, where they can convey therapeutic or pathogenic consequences through the modulation of inflammation and immune processes. Recent research has shown that exosomes can deliver entire virus genomes or virions to distant target cells, then the delivered viruses can escape the immune system and infect cells. Adenoviruses, orthomyxoviruses, paramyxoviruses, respiratory syncytial viruses, picornaviruses, coronaviruses, and rhinoviruses are mostly related to respiratory diseases. In this article, we will first discuss the current knowledge of exosomes. We will learn about the relationship between exosomes and viral infections, and We mention the inflammations caused by viruses in the airways, the role of exosomes in them, and finally, we examine the relationship between the viruses as mentioned earlier, and the regulation of inflammatory pathways that play a role in causing the disease.