Yotaro Takaku

Neutrophilic Inflammation and CXC Chemokines in Patients with Refractory Asthma

Background: There is evidence that eosinophils and neutrophils are simultaneously increased in the airways of some patients with chronic refractory asthma. The mechanisms by which neutrophils accumulate in the airways of asthmatics remain to be elucidated, however, chemoattractants for neutrophils such as CXC chemokines may affect either the accumulation or functional status of neutrophils in such patients. The objective of the present study was to identify the CXC chemokine responsible for the neutrophilic and possibly eosinophilic inflammation observed in the airways of patients with refractory asthma. Methods: Following the inhalation of hypertonic saline, induced sputum was obtained from 14 healthy controls, 16 patients with mild well-controlled nonrefractory asthma, and 14 patients with refractory asthma. Concentrations of CXC chemokines and differential inflammatory cell counts were determined. Results: The percentages of induced sputum eosinophils were significantly higher both in patients with nonrefractory asthma and in patients with refractory asthma. On the other hand, the percentages of neutrophils were increased only in sputum from patients with refractory asthma. The concentration of IL-8, but not ENA-78 or GRO-α, was also significantly increased in induced sputum from patients with refractory asthma. The concentration of IL-8 correlated significantly with the percentages of neutrophils. Conclusions: The results of the present study suggest that IL-8, but not ENA-78 or GRO-α, may contribute to the observation of neutrophilic inflammation in patients with refractory asthma.

Omalizumab Attenuates Airway Inflammation and Interleukin-5 Production by Mononuclear Cells in Patients with Severe Allergic Asthma

Background: Omalizumab, an anti-immunoglobulin E monoclonal antibody, has shown an inhibitory effect on airway inflammation, which may be associated with clinical improvement of severe asthma. This study evaluated changes in airway inflammation and cytokine release by the peripheral blood mononuclear cells (PBMCs) of Japanese patients with severe asthma after administration of omalizumab. Methods: Sixteen Japanese patients with severe asthma who were allergic to house-dust mites were enrolled in this study. Eight received omalizumab every 2 or 4 weeks for 16 weeks, and 8 control subjects were treated with conventional drug treatment. Changes in clinical scores for sputum eosinophils and levels of fraction of exhaled nitric oxide (FeNO) were measured at the time of enrollment and at week 16. Cytokines from PBMCs stimulated by house-dust mite (Dermatophagoides farinae) or ionomycin/phorbol myristate acetate (PMA) were measured at baseline and at week 16. Results: In the omalizumab-treated group, decreases in sputum eosinophils and FeNO were observed following treatment. Furthermore, the ex vivo production of interleukin (IL)-5 by PBMCs in response to both mite allergen and ionomycin/PMA decreased significantly. In contrast, interferon (IFN)-γ production was unchanged. There were no changes in any of the parameters observed in the control group. Conclusion: Omalizumab exerts inhibitory effects on airway inflammation in Japanese patients with severe allergic asthma. This treatment attenuates production of IL-5 by PBMCs stimulated with both a specific allergen and a nonspecific activator. Reduction of the Th2 inflammatory cascade likely contributes to clinical benefits; however, further studies are required to clarify these results due to the small sample size in this study.

Effect of early versus late intervention with inhaled corticosteroids on airway wall thickness in patients with asthma

Background and objective:  The aim of this study was to determine whether early versus late initiation of long‐term inhaled corticosteroid (ICS) therapy decreases airway wall thickness in patients with asthma.

Airway dimensions and pulmonary function in chronic obstructive pulmonary disease and bronchial asthma

Background and objective:  COPD and bronchial asthma are chronic airway diseases with a different pathogenesis. Comparisons of differences in airway calibre by bronchial generation between these diseases and their importance to pulmonary function have not been fully studied. We investigated airway calibre and wall thickness in relation to pulmonary function in patients with asthma, COPD, asthma plus emphysema and normal subjects using CT.

IFN-γ-inducible protein of 10 kDa upregulates the effector functions of eosinophils through β2 integrin and CXCR3

BackgroundEosinophils play an important role in the pathogenesis of bronchial asthma and its exacerbation. Recent reports suggest the involvement of IFN-γ-inducible protein of 10 kDa (IP-10) in virus-induced asthma exacerbation. The objective of this study was to examine whether CXCR3 ligands including IP-10 modify the effector functions of eosinophils.MethodsEosinophils isolated from the blood of healthy donors were stimulated with CXCR3 ligands and their adhesion to rh-ICAM-1 was then measured using eosinophil peroxidase assays. The generation of eosinophil superoxide anion (O2-) was examined based on the superoxide dismutase-inhibitable reduction of cytochrome C. Eosinophil-derived neurotoxin (EDN) release was evaluated to determine whether CXCR3 ligands induced eosinophil degranulation. Cytokine and chemokine production by eosinophils was examined using a Bio-plex assay.ResultsEosinophil adhesion to ICAM-1 was significantly enhanced by IP-10, which also significantly induced eosinophil O2- generation in the presence of ICAM-1. Both the enhanced adhesion and O2- generation were inhibited by an anti-β2 integrin mAb or an anti-CXCR3 mAb. Other CXCR3 ligands, such as monokine induced by IFN-γ (Mig) and IFN-inducible T cell α chemoattractant (I-TAC), also induced eosinophil adhesion and O2- generation in the presence of ICAM-1. IP-10, but not Mig or I-TAC, increased the release of EDN. IP-10 increased the production of a number of cytokines and chemokines by eosinophils.ConclusionsThese findings suggest that CXCR3 ligands such as IP-10 can directly upregulate the effector functions of eosinophils. These effects might be involved in the activation and infiltration of eosinophils in the airway of asthma, especially in virus-induced asthma exacerbation.

COPD assessment test and severity of airflow limitation in patients with asthma, COPD, and asthma–COPD overlap syndrome

Objective The COPD assessment test (CAT) consists of eight nonspecific scores of quality of life. The aim of this study was to compare the health-related quality of life and severity of airflow limitation in patients with asthma, COPD, and asthma–COPD overlap syndrome (ACOS) using the CAT. Methods We examined CAT and lung functions in 138 patients with asthma, 99 patients with COPD, 51 patients with ACOS, and 44 patients with chronic cough as a control. The CAT score was recorded in all subjects, and the asthma control test was also administered to patients with asthma and ACOS. The CAT scores were compared, and the relationships between the scores and lung function parameters were analyzed. Results The total CAT scores and scores for cough, phlegm, and dyspnea were higher in patients with ACOS than in patients with asthma and COPD. The total CAT scores were correlated with the percent predicted forced expiratory volume in 1 second only in patients with COPD. The total CAT scores and dyspnea scores adjusted by the percent predicted forced expiratory volume in 1 second were higher in patients with ACOS than in patients with COPD and asthma. The CAT scores and asthma control test scores were more closely correlated in patients with ACOS than in patients with asthma. Conclusion Patients with ACOS have higher disease impacts and dyspnea sensation unproportional to the severity of airflow limitation.

Eosinophil superoxide anion generation induced by adhesion molecules and leukotriene D4.

Rationale: Eosinophils preferentially accumulate at sites of inflammation in the asthmatic airway. Participation of circulating eosinophils in the airway inflammation in asthma involves their interaction with adhesion molecules expressed on the endothelial cell surface and exposure to inflammatory mediators, such as cysteinyl leukotrienes (cysLTs). Objective: To investigate whether interaction of eosinophils with adhesion molecules modifies the functions of these cells induced by cysLTs. Methods: Eosinophils were isolated from the blood of healthy donors, incubated in the EIA plates coated with adhesion proteins, and then exposed to LTD4. The generation of superoxide anion (O2–), adhesion to the plates, and release of eosinophil-derived neutrotoxin (EDN) were evaluated. Results: Neither VCAM-1 nor LTD4 (100 nM) independently induced eosinophil O2– generation, however, combined exposure to the two molecules synergistically induced eosinophil O2– generation. ICAM-1 by itself induced eosinophil O2– generation, which was enhanced by LTD4. On the contrary, P-selectin did not induce O2– generation, either in the presence or absence of LTD4. LTD4 significantly enhanced eosinophil adhesion to rh-VCAM-1 and rh-ICAM-1, but not to rh-P-selectin. Finally, we observed that combined exposure of eosinophils to LTD4 and VCAM-1 induced the release of EDN. Conclusion: Combined exposure to VCAM-1 or ICAM-1 and cysLT effectively induces the effector functions of eosinophils. Eosinophil adhesion to and migration across endothelial cells via these specific adhesion proteins and subsequent exposure to cysLTs may be mechanisms underlying activation of the effector functions of eosinophils in the asthmatic airway.

Effect of Formoterol on Eosinophil Trans-Basement Membrane Migration Induced by Interleukin-8-Stimulated Neutrophils

Background: Neutrophils are often increased in the airways of either chronic severe asthma or acute exacerbations. Neutrophils that have migrated in response to interleukin-8 (IL-8) may lead eosinophils to accumulate in the airways of patients with asthma and possibly aggravate the disease. In this study, we investigated whether formoterol modified the trans-basement membrane migration (TBM) of eosinophils stimulated with neutrophils and IL-8. Methods: Neutrophils and eosinophils were isolated from peripheral blood obtained from healthy donors. Eosinophil TBM was examined using a modified Boydens chamber technique. Neutrophils were preincubated with or without formoterol (0.1 μM) at 37°C for 30 min. Eosinophils were added to the upper compartment of a chamber with a Matrigel-coated transwell insert. Medium containing preincubated neutrophils and IL-8 was added to the lower compartment of the chamber. After a 90-minute incubation, the eosinophils that had migrated into the lower chamber were calculated using eosinophil peroxidase assays. Results: A combination of neutrophils and IL-8 significantly induced the eosinophil TBM; formoterol alone had no effect. However, formoterol modestly but significantly attenuated the TBM of eosinophils stimulated with neutrophils and IL-8. Conclusion: These results suggest that formoterol may act as a therapeutic agent on enhanced eosinophilic inflammation in acute exacerbation or persistent, severe asthma. The effect of formoterol likely involves the inhibition of neutrophil activation.

Changes in the airway lumen and surrounding parenchyma in chronic obstructive pulmonary disease

Background The purpose of this study was to examine changes in the airway lumen and parenchyma in relation to lung function in patients with chronic obstructive pulmonary disease (COPD) compared with controls. Methods We studied 70 patients with COPD and 15 normal subjects. Using reconstructed computed tomography (CT) images, we traced the bronchial trees and reconstructed 3 cm circle images around the airways exactly perpendicular to the airway axis at the peripheral, middle, and central zones of the bronchi. We measured the number of airways and vessels, the airway inner diameter, and the area of emphysema in the circles, and analyzed the relationship of these image parameters to lung function. Results Reduced airway numbers and increased upper lobe emphysema were observed even in early spirometric stages in patients with COPD compared with controls. Other findings included decreased airway inner diameter in advanced spirometric stages. The numbers of peripheral zone bronchi, the extent of the middle zone emphysematous area, and the mean airway inner diameter of the airways were the best predictors of spirometric parameters. A portion of the airways in patients with COPD showed a loss of airway patency at middle or central zone bronchi predominantly in the late spirometric stages. Lumen-obliterated bronchial trees could be traced into emphysematous areas showing air trapping. Conclusion Compared with controls, our CT observations in patients with COPD showed that airway lumen and lung parenchyma changes along airways differed by spirometric stage, and these changes were associated with decreased lung function. A portion of CT-identified emphysema in patients with COPD appeared to be due to lumen-obliterated airways in the bronchial tree.

Salbutamol Modulates the Balance of Th1 and Th2 Cytokines by Mononuclear Cells from Allergic Asthmatics

Background: There is evidence that excessive use of inhalational β2-agonists induces the deterioration of asthma. Although the exact mechanism of this remains to be elucidated, overuse of β2-agonists may impair the Th1/Th2 balance in asthmatic airways. The aim of the present study was to evaluate whether salbutamol, a representative inhalational β2-agonist, modifies the production of Th1- and Th2-type cytokines by mononuclear cells separated from patients with asthma and healthy volunteers. Methods: Peripheral blood mononuclear cells (PBMCs) obtained from 8 healthy volunteers and 10 patients with mild persistent asthma allergic to house dust mites were treated with either salbutamol or medium alone. PBMCs were then stimulated with either medium alone, house dust mite (Dermatophagoides farina, Df) allergen or a combination of ionomycin plus phorbol 12-myristate 13-acetate ester (PMA). Concentrations of IFN-γ, IL-13, TNF-α and RANTES in the cell supernatants were measured using ELISA. Results: In PBMCs from healthy volunteers, salbutamol did not modify IFN-γ production, but increased the spontaneous production of IL-13. In contrast, salbutamol significantly inhibited the spontaneous and ionomycin- plus PMA-stimulated production of IFN-γ by PBMCs from asthmatics. Salbutamol significantly enhanced both spontaneous and Df-induced production of IL-13 by PBMCs from asthmatics. Salbutamol did not modify the production of TNF-α. Finally, salbutamol enhanced the production of RANTES induced by Df allergen in asthmatics. Conclusions: Salbutamol inhibits IFN-γ and enhances IL-13 production by PBMCs from asthmatics. These effects would promote a Th1/Th2 imbalance in the airways and may therefore contribute to the deterioration of asthma.