Shohei Takata

Eosinophilic airway inflammation induced by repeated exposure to cigarette smoke

Acute exposure to cigarette smoke causes airway hyperresponsiveness (AHR) in guinea-pigs, which resolves within a few hours. Repeated exposure may have a different effect on the airways. To address this question, guinea-pigs were repeatedly exposed to cigarette smoke (six cigarettes for 1 h x day(-1)) for 14 consecutive days. Airway responsiveness to inhaled histamine and differential cell counts in bronchoalveolar lavage fluid (BALF) were evaluated 1 day after the last exposure. Significant neutrophilia in BALF was observed after 3 days of smoke exposure. Significant eosinophilia in BALF and AHR were observed after 14 days of smoke exposure, but not after 3 or 7 days of smoke exposure. These changes persisted until 3 days after the last exposure and resolved 7 days afterwards. Histologically, the recruited eosinophils were observed predominantly in the airways, but not in the alveoli. Treatment with E-6123, a specific platelet-activating factor receptor antagonist (1 mg x kg(-1) x day(-1) p.o. during smoke exposure) significantly inhibited the eosinophil influx and AHR. Repeated exposure to cigarette smoke may induce prolonged airway inflammation and airway hyperresponsiveness in guinea-pigs. Platelet-activating factor or platelet-activating factor-like lipids may play a key role in airway hyperresponsiveness, presumably by the induction of eosinophilic airway inflammation.

Comparison of Aspergillus galactomannan antigen testing with a new cut-off index and Aspergillus precipitating antibody testing for the diagnosis of chronic pulmonary aspergillosis.

Background and objective:  The usefulness of two tests in the serodiagnosis of chronic pulmonary aspergillosis (CPA) was compared. The tests were the serum Aspergillus galactomannan antigen test (Platelia (R) Aspergillus) by enzyme‐linked immunoassay (EIA) using old and new cut‐off indexes, and the Aspergillus precipitating antibody test.

Effect of inhaled glucocorticoid on the cellular profile and cytokine levels in induced sputum from asthmatic patients

Abstract. Cytokines are considered to play a role in the airway inflammation of bronchial asthma. We examined the cellular profile and cytokine levels in induced sputum samples obtained before and after treatment with beclomethasone dipropionate (BDP, 800 μg/day, for 4 weeks) in 12 mild to moderate asthmatic subjects who had not previously received inhaled glucocorticosteroids. Sputum was induced with a 20-min inhalation of 3% saline by an ultrasonic nebulizer. The freshly expectorated sputum separated from the saliva was analyzed for cell counts, for the concentration of interleukin-8 (IL-8), and for the concentration of granulocyte-macrophage colony-stimulating factor (GM-CSF). The mean percentage of eosinophils in the sputum samples decreased significantly after BDP treatment, but no significant change in the percentage of neutrophils was observed. The mean IL-8 and GM-CSF levels also decreased significantly after treatment. The BDP treatment was associated with an increase in the mean peak expiratory flow (PEF) and with a decrease in the diurnal variation of PEF. These results suggest that inhaled steroids improve airway inflammation and lung function in asthmatics, presumably in part by inhibiting the synthesis of inflammatory cytokines such as IL-8 and GM-CSF.

Once–Daily Theophylline Reduces Serum Eosinophil Cationic Protein and Eosinophil Levels in Induced Sputum of Asthmatics

Background: Because eosinophilic airway inflammation is a characteristic feature of bronchial asthma, the treatment of airway inflammation is important in the management of asthma. Theophylline has been reported to reduce airway inflammation, in addition to its well–known bronchodilating effect. Objective: In order to evaluate the effects of theophylline on airway inflammation, we investigated 48 subjects with mild and moderate asthma. Methods: The patients were randomly divided into two groups, with or without theophylline treatment (control n = 24; theophylline, n = 24). We examined the level of serum eosinophil cationic protein (ECP), induced sputum samples, and peak expiratory flow (PEF) and obtained spirograms before and after 4 weeks of treatment with once–daily theophylline (200–600 mg/day) of subjects with mild or moderate asthma. Results: Theophylline significantly increased morning and evening PEF and significantly decreased the diurnal variation of PEF. After treatment with theophylline, both serum ECP and the percentage of eosinophils in induced sputum were significantly decreased. In contrast, peripheral blood eosinophil count was unchanged after treatment with theophylline. Conclusions: These findings suggest that theophylline reduces airway inflammation and the severity of asthma, presumably via suppression of both eosinophil activity and subsequent eosinophil infiltration of the airways.

Pituitary adenylate cyclase activating peptide regulates neurally mediated airway responses

To clarify the protective effects of pituitary adenylate cyclase activating peptide (PACAP) on airway narrowing, we examined the effects of PACAP on smooth muscle contraction and plasma extravasation in guinea-pig airways. Smooth muscle contraction evoked by electrical field stimulation (EFS) or exogenously applied acetylcholine (ACh) or substance P (SP) was measured before and after PACAP in vitro. The effect of PACAP on airway plasma extravasation was also measured in vivo. In trachea, PACAP (10(-9) - 10(-7) M) significantly suppressed smooth muscle contraction evoked by EFS without affecting ACh sensitivity, suggesting that PACAP inhibits cholinergic neuroeffector transmission. In the main bronchi, PACAP (10(-9) - 10(-8) M) significantly suppressed the contraction evoked by EFS without affecting SP sensitivity in the presence of atropine, suggesting that PACAP inhibits SP release from excitatory nonadrenergic noncholinergic (eNANC) nerves. In animals treated with atropine and propranolol, PACAP attenuated the increase in plasma extravasation induced by electrical vagus stimulation or by SP. These results suggest that pituitary adenylate cyclase activating peptide may play a role in modulation of airway responses through inhibition of cholinergic and noncholinergic mechanisms.

Ipratropium bromide protects against bronchoconstriction during bronchoscopy

Pulmonary function is reportedly impaired by fiberoptic bronchoscopy. We investigated the effect of two anticholinergic agents, intramuscular atropine and inhaled ipratropium bromide, on bronchoconstriction in 29 patients who were undergoing diagnostic bronchoscopy. The patients were divided into three groups; the first received 0.5 mg of atropine intramuscularly; the second took four puffs of 0.02 mg ipratropium bromide aerosolized by a metered-dose inhaler, and the third inhaled four puffs of a placebo. Fifteen minutes later a standardized topical anesthetic, lidocaine, was administered, and a bronchoscopic examination was performed. Pulmonary function was measured before and 15 minutes after each step. Pulmonary function was not affected by the treatment with anticholinergics or the placebo. In the placebo and the atropine groups, the topical anesthesia produced significant reductions in forced expiratory volume in 1 second (FEV,) and peak expiratory flow rate (PEFR); further reductions in these values were observed after bronchoscopy. In the group treated with ipratropium bromide there were no significant changes in FEV, and PEFR after topical anesthesia. Bronchoscopy induced significant reductions in FEV1 and PEFR, but the changes were significantly smaller than those seen in the placebo and atropine groups. The results suggest that the deleterious effect of bronchoscopy on pulmonary function is due to topical lidocaine anesthesia and to the bronchoscopic examination itself. Inhaled ipratropium bromide protects against these deleterious effects, whereas intramuscular atropine does not.

Effect of BAY u3405, a thromboxane A2 receptor antagonist, on neuro-effector transmission in canine tracheal tissue

Thromboxane A2 (TXA2) is reported to potentiate vagal nerve neuro-effector transmission in airway smooth muscle tissue. We investigated the effects of BAY u3405 (3(R)-[[4-fluorophenyl)sulfonyl]amino]-1,2,3,4,-tetrahydro-9H-carbazole - 9-propanoic acid), a potent and selective TXA2 receptor antagonist, on the increase in vagal nerve neuro-effector transmission induced by a TXA2 mimetic, U-46619, in the canine trachea. We measured the contractions of canine tracheal smooth muscle evoked by electrical field stimulation (EFS) and by acetylcholine (ACh) in the presence and absence of a subthreshold dose of U-46619 (the highest dose that did not induce any smooth muscle contraction). We then examined whether BAY u3405 inhibited the effect of U-46619 on tracheal smooth muscle. The following results were obtained: (i) subthreshold doses of U-46619 (10(-10) M and 10(-9) M) significantly increased the amplitude of the contractions evoked by EFS; (ii) by contrast, U-46619 had no effect on the contractile response of smooth muscle to exogenously applied ACh; (iii) the contraction evoked by EFS was completely abolished by the application of atropine (10(-6) M) or tetrodotoxin (10(-7) M), indicating that EFS caused the smooth muscle contraction through the release of ACh from vagal nerve terminals; and (iv) pretreatment with BAY u3405 (10(-6) M) abolished the excitatory action of U-46619 on the amplitude of twitch contraction evoked by EFS in the trachea. These results indicate that U-46619, at low concentrations, has a prejunctional action stimulating neuro-effector transmission, presumably increasing ACh release from vagal nerve terminals through TXA2 receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of asthma with airflow limitation, COPD, and COPD with variable airflow limitation in older subjects in a general Japanese population: The Hisayama Study

BACKGROUND Elucidating the prevalence of asthma and chronic obstructive pulmonary disease (COPD) is important for designing a public health strategy. Recent studies have discriminated a phenotype of COPD with variable airflow limitation (COPD-VAL) associated with asthma-COPD overlap syndrome. Its prevalence remains uncertain. The age and occupational distributions in the town of Hisayama and in Japan are nearly identical. Each diseases prevalence was estimated for the towns residents. METHODS In 2008, town residents (≥ 40 years) were solicited to participate in a health checkup. Individuals with abnormal spirometry (forced expiratory volume in 1s/forced vital capacity [FEV1/FVC]<70% and/or %FVC<80%) were recommended for further evaluations. Two pulmonologists in a blinded fashion reviewed their medical records, including bronchodilator reversibility. Individuals with airflow limitation were classified as having asthma, COPD, COPD-VAL, or other diseases. The prevalence of each disease was then estimated. RESULTS A total of 2100 residents (43.4% of residents in the age group) completed spirometry. In 455 residents with abnormal spirometry, 190 residents had further evaluations, and the medical records of 174 residents were reviewed. The prevalence of asthma with airflow limitation, COPD, and COPD-VAL, were 2.0%, 8.4%, and 0.9%, respectively. The prevalence of COPD and COPD-VAL were higher in men and smokers than in women and never-smokers. The prevalence of COPD, but not COPD-VAL or asthma, increased with age. CONCLUSION The prevalence of asthma with airflow limitation, COPD, and COPD-VAL were estimated in a population of residents (≥ 40 years) in Hisayama.

Role of thromboxane-A2 and cholinergic mechanisms in bronchoconstriction induced by cigarette smoke in guinea-pigs

Acute exposure to cigarette smoke provokes bronchoconstriction and increases the concentration of thromboxane (Tx) A2 in bronchoalveolar lavage (BAL) fluid. The purpose of this study was to investigate the role of TxA2 and cholinergic mechanisms in the airway response induced by exposure to cigarette smoke in guinea-pigs. Anaesthetized animals were exposed to 200 puffs of smoke for 10 min. The amount of Evans blue dye extravasated into the bronchial tissue was then measured BAL was performed to determine cell counts and the concentration of TxB2, a stable metabolite of TxA2. The effects of pretreatment with a Tx synthase inhibitor, OKY-046 (10 mg.kg-1), and/or atropine (1 mg.kg-1) were evaluated. Exposure to cigarette smoke caused significant bronchoconstriction (284 +/- 33% of baseline pulmonary resistance (RL)) and plasma extravasation (30.0 +/- 3.8 vs 16.8 +/- 2.6 ng.mg-1 of sham control; main bronchi). OKY-046 or atropine significantly inhibited the bronchoconstriction to a similar extent, without affecting the plasma extravasation. Combined use of these compounds had no additive effect. The cigarette smoke caused significant increase in TxB2 (48 +/- 10 vs 14 +/- 1 pg.mL-1 of sham control) in BAL fluid, which was abolished by OKY-046 but not by atropine. The cellularity in BAL fluid was not different among groups. These results suggest that the bronchoconstriction induced by cigarette smoke is partially mediated by thromboxane A2, which is dependent on a cholinergic pathway.

Cultured epithelial cells release cyclooxygenase-dependent and cyclooxygenase-independent factors that inhibit cholinergic contraction of canine airway smooth muscles.

We observed the effects of supernatants from cultured epithelial cells on the contraction of tracheal smooth muscle evoked by acetylcholine (ACh) or by electrical field stimulation (EFS). Cultured canine tracheal epithelial cells were incubated in Krebs solution with or without indomethacin (10(-5)M) for 30 and 120 min. The amplitude of the tracheal smooth muscle contractions evoked by EFS or exogenously applied ACh were measured before and after the application of each supernatant in the combined presence of both indomethacin (10(-5)M) and propranolol (10(-6)M). The control supernatant incubated without indomethacin markedly suppressed the amplitude of the contraction evoked by EFS, but not by ACh. The supernatant incubated with indomethacin for 30 min did not show any effects on the contractile responses evoked by EFS or ACh. However, the supernatants from the cultured epithelial cells incubated for a longer period (120 min) in the presence of indomethacin significantly suppressed the contraction evoked by EFS, but not by ACh. The prostaglandin E2 (PGE2) concentration was markedly higher in the supernatants incubated without indomethacin (1.39 +/- 0.51 ng/ml, 30 min incubation) than in those with indomethacin (0.02 +/- 0.01 ng/ml, 30 min incubation, and 0.06 +/- 0.01 ng/ml, 120 min incubation). To determine whether PGE2 is responsible for the inhibitory effect of the supernatants, we evaluated the effects of PGE2 on the resting tone, and EFS- or ACh-evoked contraction. 10(-12) to 10(-6) M of PGE2 showed no significant effect on the resting tone. 10(-9) M of PGE2, corresponding to the concentration of the supernatants incubated without indomethacin, and 10(-11) M of PGE2, to that of the supernatants incubated with indomethacin, showed a similar extent of inhibitory effects to the corresponding supernatants on the EFS-evoked contraction, and no effect on the ACh-evoked contraction. These results suggest that cultured airway epithelial cells release at least two factors spontaneously even without stimulation. One of these factors may be prostanoid (PGE2), which acts prejunctionally to inhibit the contractile response. The other factor is distinct from prostanoid and inhibits smooth muscle contraction, presumably by suppressing ACh release from vagus nerve termini.