Shiho Furusho

Exhaled nitric oxide levels in patients with atopic cough and cough variant asthma

Background and objective:  Atopic cough (AC) is an established clinical entity in Japan, in which patients present with a chronic persistent non‐productive cough. Exhaled nitric oxide (NO) is a biomarker of eosinophilic airway inflammation. The present study examined whether exhaled NO levels were increased in AC in comparison with cough variant asthma (CVA) and bronchial asthma (BA).

Sputum Eosinophilia, Airway Hyperresponsiveness and Airway Narrowing in Young Adults with Former Asthma

BACKGROUND 30-80% of outgrown asthma subjects develop symptoms again later in life. We investigated inflammation and function of lower airway in adolescents with former asthma. METHODS 326 never-smoking young adults (mean age 24.0 years) were interviewed with special emphasis on history of asthma. Diagnosis of asthma was based on GINA guidelines. Former asthma subjects consisted of ones with a history of physician-diagnosed childhood asthma, who had been free of asthma symptoms without the use of medication for at least 10 years prior to the study. Provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 second (FEV(1))(PC(20)) and eosinophil percentage in induced sputum were measured. RESULTS 31 subjects were former asthma subjects (FBA), 11 subjects were current asthma subjects (CBA) and 284 subjects had no history of asthma (non-BA). PC(20) and FEV(1)/FVC ratio were significantly lower in the FBA group than in the non-BA group (P < 0.01). Maximal mid-expiratory flow (MMF) was significantly lower in the FBA group than in the non-BA group (P < 0.05). Sputum eosinophil percentage was significantly increased in the FBA group compared with the non-BA group (P < 0.01). PC(20) was significantly lower in the CBA group than in the FBA and non-BA groups (P < 0.01). FEV(1), FEV(1)/FVC ratio and MMF were significantly lower in the CBA group than in the FBA group (P < 0.05, P < 0.05 and P < 0.05, respectively) and the non-BA group (P < 0.01, P < 0.01 and P < 0.05, respectively). Sputum eosinophils were significantly higher in the CBA group than in the FBA and non-BA groups (P < 0.01). CONCLUSIONS This study shows that subjects with long-term outgrown asthma continue to have airway eosinophilic inflammation, airway hyperresponsiveness and airway narrowing.

Eosinophilic Inflammation, Remodeling of Lower Airway, Bronchial Responsiveness and Cough Reflex Sensitivity in Non-Asthmatic Subjects with Nasal Allergy

Background: It has been reported that nasal allergy influences the lower airway inflammation and functions. We elucidated whether nasal allergy would contribute to lower airway inflammation and functions. Methods: 266 subjects aged 21–39 years were interviewed with special emphasis on history of asthma and nasal allergies (perennial allergic rhinitis (PAR) and seasonal allergic rhinitis (Japanese cedar pollinosis; PO)). Symptomatic subject was defined when nasal symptoms were present during a 3-week study period. Pulmonary function, provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 s (PC20), capsaicin cough threshold defined as capsaicin concentration eliciting 5 or more coughs (C5) and eosinophil percentage in hypertonic saline-induced sputum were measured. Results: Based on the interview, 232 subjects without asthma were divided into symptomatic (n = 25) and asymptomatic (n = 22) PAR, PO on-season (n = 15) and off-season (n = 36), and non-nasal allergy subjects (control) (n = 134). Sputum eosinophils were significantly greater in symptomatic PAR than another four groups (p < 0.01). FEV1/FVC ratio was significantly lower in PAR than control (p < 0.05). Maximum mean expiratory flow was lower in PAR than control (asymptomatic: p < 0.05, symptomatic: p = 0.06). C5 was not different among groups. PAR tended to have a lower PC20 compared to control (symptomatic: p = 0.078; asymptomatic: p = 0.086). Conclusions: These results suggest that eosinophilic inflammation occurred in symptomatic period of PAR may contribute to development of lower airway remodeling and bronchial hyperresponsiveness. Reversely, PO may not be associated with lower airway eosinophilic inflammation or abnormal bronchial functions. Nasal allergy dose not influence the cough reflex sensitivity.

Role of intercellular adhesion molecule‐1 in a murine model of toluene diisocyanate‐induced asthma

Background Adhesion molecules such as intercellular adhesion molecule‐1 (ICAM‐1) are thought to contribute to the airway inflammation and airway hyper‐responsiveness (AHR) of allergic asthma. Some differences from allergic asthma have been noted, including airway neutrophilia, and the involvement of ICAM‐1 in toluene diisocyanate (TDI) asthma is currently unclear.

Evaluation of airway hyperresponsiveness and exhaled nitric oxide as risk factors for airway remodeling in patients with stable asthma.

Chronic eosinophilic airway inflammation, airflow limitation, and airway hyperresponsiveness (AHR) are distinctive features of bronchial asthma. Exhaled nitric oxide (eNO) is a marker of eosinophilic airway inflammation. Airway remodeling due to chronic airway inflammation results in fixed airway obstruction. Asthmatic patients have been reported to have greater declines in forced expiratory volume in 1 second (FEV(1)) over time than nonasthmatic patients. This longitudinal observational study aimed to elucidate outcomes and risk factors for the decline in FEV(1) in patients with stable asthma. Postbronchodilator FEV(1) was measured in 30 outpatients with stable asthma every 6 months for 5 years. We calculated the rate of decline in postbronchodilator FEV(1) (deltaFEV(1)/year) in each subject and adjusted deltaFEV(1)/year with predictive FEV(1). Patients were examined while their asthma was well controlled. In the first observation period, we measured AHR to methacholine (the provocative concentration of methacholine causing a 20% fall in FEV(1) [PC(20)]). In the second observation period (defined as the period over 2 years from start of observation), we measured methacholine PC(20) and eNO. The mean deltaFEV(1)/year (SEM) was -36 +/- 4 mL/year and the adjusted deltaFEV(1)/year (SEM) was -0.015 +/- 0.001/year. Adjusted deltaFEV(1)/year did not correlate with eNO measured during the second observation period or methacholine PC(20) measured during the first observation period. On the other hand, methacholine PC(20) measured during the latter period was correlated significantly with adjusted deltaFEV(1)/year. Persistent AHR may be a risk factor for longitudinal decline in FEV(1) in asthma patients even if their asthma is stable and well controlled by inhaled corticosteroid.

Comparison of cough reflex sensitivity after an inhaled antigen challenge between actively and passively sensitized guinea pigs

BackgroundLate asthmatic response is observed following antigen challenge in actively, but not passively, sensitized guinea pigs. Although cough reflex sensitivity is increased after antigen challenge in actively sensitized guinea pigs, it is unknown whether the antigen-induced increase in cough reflex sensitivity develops in passively sensitized animals. The aim of this study was to compare the cough reflex sensitivity to inhaled capsaicin after an inhaled antigen challenge between actively and passively sensitized guinea pigs.MethodsMeasurement of number of coughs elicited by increasing concentrations of capsaicin (10-6 and 10-4 M) and bronchial responsiveness to ascending concentrations of methacholine, and analysis of bronchoalveolar lavage fluid (BALF) were separately performed 24 h after an antigen challenge in actively and passively sensitized guinea pigs.ResultsPercentage of eosinophils in BALF and bronchial responsiveness to methacholine were increased 24 h after the antigen challenge in both actively and passively sensitized animals compared with saline-challenged actively and passively sensitized animals, respectively. Absolute number of eosinophils in BALF from actively sensitized and antigen-challenged guinea pigs was significantly greater than that from passively sensitized and antigen-challenged animals. Cough response to capsaicin and concentration of substance P in BALF were increased 24 h after the antigen challenge in actively sensitized guinea pigs, but not in passively sensitized guinea pigs. Bronchial responsiveness, cough reflex sensitivity and substance P concentration and total cells in BALF were increased in actively sensitized and saline challenged guinea pigs compared with passively sensitized and saline challenged animals.ConclusionThe results suggest that active sensitization per se increases cough reflex sensitivity accompanied by increased inflammatory cells and substance P level in BALF, and antigen challenge further increases them, while simple IgE- and/or IgG-mediated allergic reaction per se or the low intensity of eosinophil infiltration in the airway itself may not affect cough reflex sensitivity in guinea pigs.

Effects of macrolides on antigen-induced increases in cough reflex sensitivity in guinea pigs.

BACKGROUND Macrolides are antibiotics that have anti-inflammatory activities. Hence, they are used for both acute and chronic inflammatory airway diseases. However, the effects of these agents on allergic airway disorders presenting with an isolated chronic cough, such as non-asthmatic eosinophilic bronchitis and eosinophilic tracheobronchitis with cough hypersensitivity (atopic cough), still remain to be elucidated. OBJECTIVE To determine if macrolides are effective in the management of chronic cough caused by eosinophilic airway inflammation. METHODS The cough reflex sensitivity to inhaled capsaicin was measured at 48h after challenge with an aerosolized antigen in actively sensitized guinea pigs. The 14-, 15- or 16-membered macrolides (erythromycin, azythromycin, or josamycin, respectively) were given intraperitoneally every 12h after the antigen challenge. Bronchoalveolar lavage and the resection of the tracheal tissue were performed immediately after the measurement of the cough response to capsaicin. RESULTS The antigen-induced increase in the number of coughs elicited by capsaicin inhalation was significantly reduced by treatments with erythromycin and azythromycin, but not with josamycin. Erythromycin dose-dependently inhibited the increases in the substance P, prostaglandin E(2) and leukotriene B(4) levels, but not the histamine levels, in the bronchoalveolar lavage fluid. However, erythromycin did not influence the antigen-induced decrease in the neutral endopeptidase (NEP) activity in the tracheal tissue. CONCLUSIONS Both 14- and 15-membered, but not 16-membered, macrolides could reduce the antigen-induced cough reflex hypersensitivity by inhibiting the antigen-induced release of the afferent sensory nerve sensitizers. These macrolides may be therapeutically useful for the treatment of isolated chronic cough based on cough reflex hypersensitivity in allergic airway diseases such as non-asthmatic eosinophilic bronchitis and atopic cough.