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Background: Tocilizumab is considered a critical treatment for severe COVID-19. Thus far, there are no established means of predicting outcomes of administering tocilizumab. Our goal was to determine the factors that predict the prognosis of patients with COVID-19 receiving tocilizumab. Methods: All patients admitted to our hospital from March 2020 to July 2021 who had received tocilizumab for COVID-19 were retrospectively identified from hospital charts. We identified 92 patients who were eligible for this observational cohort study. We assessed age, dyspnoea, number of comorbidities, history of cancer, neutrophil and lymphocyte counts, neutrophil/lymphocyte ratio, lactate dehydrogenase, and total bilirubin. We also analysed the relationship between mortality and oxygen saturation/fraction of inspired oxygen (SpO2/FIO2) and ratio of oxygen concentration to respiratory rate (ROX index). We assessed these data using the Cox proportional hazard and ROC curve models. Results: Survivors (n = 56; mean age 65 years) were younger than those who died (n = 36; mean age 78 years). According to multivariable analysis, multiple comorbidities, history of cancer, CURB-65 score, neutrophil and lymphocyte counts, neutrophil/lymphocyte ratio, and lactate dehydrogenase were all greater in those who died than in those who survived. There were no significant differences in dyspnoea and total bilirubin. The SpO2/FIO2 ratio 3 days after treatment with tocilizumab was strongly associated with subsequent mortality. According to multivariate analysis, of the variables analysed, only the SpO2/FIO2 ratio 3 days after treatment with tocilizumab was significantly associated with mortality rate (p = 0.029; hazard ratio = 0.987, 95% confidence interval 0.977–0.997). Conclusions: The SpO2/FIO2 ratio 3 days after treatment with tocilizumab is a useful prognostic indicator in patients with COVID-19. Our findings indicate that aggressive respiratory therapy and/or additional treatment should be instigated when the SpO2/FIO2 ratio has not improved 3 days after treatment with tocilizumab.

Although the pathogenesis of pulmonary fibrosis remains unclear, it is known to involve epithelial injury and epithelial-mesenchymal transformation (EMT) as a consequence of cigarette smoke (CS) exposure. Moreover, smoking deposits iron in the mitochondria of alveolar epithelial cells. Iron overload in mitochondria causes the Fenton reaction, leading to reactive oxygen species (ROS) production, and ROS leakage from the mitochondria induces cell injury and inflammation in the lungs. Nevertheless, the mechanisms underlying iron metabolism and pulmonary fibrosis are yet to be elucidated. In this study, we aimed to determine whether iron metabolism and mitochondrial dysfunction are involved in the pathogenesis of pulmonary fibrosis. We demonstrated that administration of the iron chelator deferoxamine (DFO) reduced CS-induced pulmonary epithelial cell death, mitochondrial ROS production, and mitochondrial DNA release. Notably, CS-induced cell death was reduced by the administration of an inhibitor targeting ferroptosis, a unique iron-dependent form of non-apoptotic cell death. Transforming growth factor-β-induced EMT of pulmonary epithelial cells was also reduced by DFO. The preservation of mitochondrial function reduced Transforming growth factor-β-induced EMT. Furthermore, transbronchial iron chelation ameliorated bleomycin-induced pulmonary fibrosis and leukocyte migration in a murine model. Our findings indicate that iron metabolism and mitochondrial dysfunction are involved in the pathogenesis of pulmonary fibrosis. Thus, they may be leveraged as new therapeutic targets for pulmonary fibrosis.

Background MicroRNAs (miRNAs) may facilitate cell-to-cell communication via extracellular vesicles (EVs). The biological roles of miRNAs in EVs on allergic airway inflammation is unclear. Methods Airway secreted EVs (AEVs) were isolated from bronchoalveolar lavage fluid (BALF) of control and house dust mite (HDM) allergen-exposed HDM-sensitized mice. The expression of miRNAs in AEVs or miRNAs and mRNAs in lung tissue was analyzed using miRNA microarray. Results The amount of AEV increased 8.9-fold in BALF from HDM-exposed mice compared with that from sham-control mice. HDM exposure resulted in significant changes in the expression of 139 miRNAs in EVs and 175 miRNAs in lung tissues, with 54 miRNAs being common in both samples. Expression changes of these 54 miRNAs between miRNAs in AEVs and lung tissues after HDM exposure were inversely correlated. Computational analysis revealed that 31 genes, including IL-13 and IL-5Ra, are putative targets of the miRNAs upregulated in AEVs but downregulated in lung tissues after HDM exposure. The amount of AEV in BALF after HDM exposure was diminished by treatment with the sphingomyelinase inhibitor GW4869. The treatment with GW4869 also decreased Th2 cytokines and eosinophil counts in BALFs and reduced eosinophil accumulation in airway walls and mucosa. Conclusion These results indicate that selective sorting of miRNA including Th2 inhibitory miRNAs into AEVs and increase release to the airway after HDM exposure would be involve in the pathogenesis of allergic airway inflammation. This article is protected by copyright. All rights reserved.

BACKGROUND The serum level of eosinophil-derived neurotoxin (EDN), a protein present in eosinophil granules, correlates with the severity of childhood asthma. However, the relationship between the serum EDN level and the severity of adult asthma has not been sufficiently investigated. OBJECTIVE This study aimed to elucidate the correlation between the serum EDN level and markers of severity in adult asthma. METHODS The subjects comprised 83 adult patients who had asthma and who were undergoing treatment. Of these patients, 40 were positive for house-dust-specific immunoglobulin E (IgE) antibodies; 9 patients with severe adult asthma who were treated with omalizumab were included in the study. We measured the blood eosinophil count, serum EDN, and eosinophil cationic protein levels before investigating the correlations of these parameters with lung function and symptom score. RESULTS There were no significant correlations between the blood eosinophil count or serum EDN or eosinophil cationic protein level with lung function and the symptom score in patients with asthma. However, serum EDN level was inversely correlated with the decrease percentage forced expiratory volume in 1 second (%FEV1) in patients positive for house-dust-specific IgE antibody (R = -0.54; p < 0.05), whereas no such correlation was observed in patients with negative results for house-dust-specific IgE antibody (R = 0.11; p = 0.468). A significant correlation was observed between a decrease in serum EDN level from baseline and lung function improvement after 8 weeks of omalizumab therapy (R = -0.77; p = 0.015). CONCLUSION Serum EDN level may be a useful marker for monitoring persistent airflow limitation in adult patients with asthma who had positive results for house-dust-specific IgE antibodies.

Background: Influenza A virus (FluA) is a major pathogen that leads public health problems worldwide. Especially novel strains of FluA cause pandemic with mortality. Carbocisteine is a mucoregulatory drug that reduces FluA-induced exacerbations in pulmonary diseases, such as asthma and chronic obstructive pulmonary disease. However, little is known about the mechanism of inhibitory effects of carbocisteine on FluA infection in vivo . Objective: To determine whether carbocisteine attenuates FluA replication in the bronchoalveolar lavage fluids (BALFs) in FluA-infected mice. Methods: C57BL/6J mice were infected with FluA (Udorn/307/72(H3N2)) intranasally. We administered carbocisteine (100mg/kg) intraperitoneally twice a day for 5 days, from 3 days before the FluA infection to the day after the FluA infection. Two days after the FluA infection, we collected lung tissues and BALFs from FluA with vehicle and from FluA with carbocisteine-exposed mice. We measured FluA replication of BALFs using plaque assay and counted the number of inflammatory cells in BALFs. Results: Carbocisteine significantly attenuates FluA replication in the BALFs of FluA-infected mice when compared to the FluA replication in control mice, but it did not inhibit the infiltration of neutrophils in BALFs by FluA infection. Conclusion: Our data suggest that carbocisteine might protect against FluA replication in vivo.

Background: Acute lung injury (ALI) is leading causes of mortality in critically ill patients. However, there is no useful biomarker that accurately reflects biological responses in the airway of ALI. Exosomes can serve as mediators of intercellular communication, such as messenger RNA (mRNA), microRNA and functional protein to neighboring cells. Objective: To determine whether lipopolysaccharide (LPS)-induced exosomal mRNAs in the bronchoalveolar lavage fluids (BALFs) accurately reflect inflammatory responses to LPS in the lung of animal model of ALI. Methods: We collected lung tissues and BALFs from LPS or PBS-exposed mice. We isolated total RNAs from lung tissues and examined global gene expression analysis using microarray. We also isolated exosomes from BALFs and quantified the number of exosomes using the q-Nano vesicle counter. Global mRNAs Expressions in exosomes were examined using next-generation sequencing techniques. Results: The number of exosomes in the BALFs of LPS-exposed mice did not show any change when compared to that of control mice. However, the total amount of RNA in exosomes significantly increased in the BALFs of LPS-exposed mice. We identified 67 LPS-inducible exosomal mRNAs in both the BALFs and lung tissues. After LPS-exposure, the change of expression levels between exosomal mRNA in the BALFs and mRNA in lung tissues were seen in direct correlation. Conclusion: Our data suggest that LPS-induced exosomal mRNAs in the BALFs accurately reflect biological response to LPS in the lung tissues. Thus, exosomal mRNAs in the BALFs might be useful biomarkers for ALI.

Background Inhaled corticosteroids enhance airway epithelial barrier integrity. However, the mechanism by which they accomplish this is unclear. Therefore, we investigated steroid-inducible genes and signaling pathways that were involved in enhancing airway epithelial barrier integrity. Methods A human bronchial epithelial cell line (16HBE cells) was cultured with 10 −6 M dexamethasone (DEX) for 3 days to enhance epithelial barrier integrity. After measuring transepithelial electrical resistance (TER) and paracellular permeability, we extracted total RNA from 16HBE cells and performed microarray and pathway analysis. After we identified candidate genes and a canonical pathway, we measured TER and immunostained for tight junction (TJ) and adherent junction (AJ) proteins in cells that had been transfected with specific small interfering RNAs (siRNAs) for these genes. Results We identified a nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated oxidative stress response pathway which was primarily involved in the steroid-induced enhancement of airway epithelial barrier integrity. Transfecting cells with Nrf2 specific siRNA reduced the steroid-induced enhancement of airway epithelial barrier integrity and the accumulation of TJ and AJ proteins at sites of cell–cell contact. Moreover, based on pathway analysis, aldehyde oxidase 1 (AOX1) was identified as a downstream enzyme of Nrf2. Transfecting cells with AOX1 -specific siRNA also reduced the steroid-induced enhancement of airway epithelial barrier integrity. Conclusions Our results indicated that the Nrf2/AOX1 pathway was important for enhancing airway epithelial barrier integrity. Because the airway epithelium of asthmatics is susceptible to reduced barrier integrity, this pathway might be a new therapeutic target for asthma.