Dataset Information

Assessment of peripheral airway function following chronic allergen challenge in a sheep model of asthma.

ABSTRACT:

Background

There is increasing evidence that the small airways contribute significantly to the pathophysiology of asthma. However, due to the difficulty in accessing distal lung regions in clinical settings, functional changes in the peripheral airways are often overlooked in studies of asthmatic patients. The aim of the current study was to characterize progressive changes in small airway function in sheep repeatedly challenged with house dust mite (HDM) allergen.

Methodology/principal findings

Four spatially separate lung segments were utilized for HDM challenges. The right apical, right medial, right caudal and left caudal lung segments received 0, 8, 16 and 24 weekly challenges with HDM respectively. A wedged-bronchoscope technique was used to assess changes in peripheral resistance (R(p)) at rest, and in response to specific and non-specific stimuli throughout the trial. Allergen induced inflammatory cell infiltration into bronchoalveolar lavage and increases in R(p) in response to HDM and methacholine were localized to treated lung segments, with no changes observed in adjacent lung segments. The acute response to HDM was variable between sheep, and was significantly correlated to airway responsiveness to methacholine (r(s) = 0.095, P<0.01). There was no correlation between resting R(p) and the number of weeks of HDM exposure. Nor was there a correlation between the magnitude of early-phase airway response and the number of HDM-challenges.

Conclusions

Our findings indicate that airway responses to allergic and non-allergic stimuli are localized to specific treated areas of the lung. Furthermore, while there was a decline in peripheral airway function with HDM exposure, this decrease was not correlated with the length of allergen challenge.

SUBMITTER: Van der Velden J

PROVIDER: S-EPMC3236205 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature

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Publications

Assessment of peripheral airway function following chronic allergen challenge in a sheep model of asthma.

Van der Velden Joanne J Barker Donna D Barcham Garry G Koumoundouros Emmanuel E Snibson Kenneth K

PloS one 20111212 12

<h4>Background</h4>There is increasing evidence that the small airways contribute significantly to the pathophysiology of asthma. However, due to the difficulty in accessing distal lung regions in clinical settings, functional changes in the peripheral airways are often overlooked in studies of asthmatic patients. The aim of the current study was to characterize progressive changes in small airway function in sheep repeatedly challenged with house dust mite (HDM) allergen.<h4>Methodology/princip ...[more]

PMID: 22174883

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Project description:OBJECTIVE:We aimed to investigate peripheral blood eosinophil chemotaxis, generation of spontaneous reactive oxygen species (ROS), and apoptosis in patients with allergic asthma after bronchial allergen challenge. MATERIAL AND METHODS:A total of 18 patients with allergic asthma (AA), 14 with allergic rhinitis (AR), and 10 healthy subjects (HS) underwent bronchial challenge with a specific allergen extract. Eosinophils from peripheral blood were isolated 24 h before as well as 7 and 24 h after bronchial allergen challenge. Chemotaxis, spontaneous ROS production in eosinophils, and apoptosis were analyzed by flow cytometry. Serum and induced sputum IL-5 levels were measured by ELISA; the cell count in sputum was analyzed by the May-Grünwald-Giemsa method. RESULTS:Before bronchial allergen challenge, peripheral blood eosinophil chemotaxis, spontaneous ROS production was enhanced and eosinophil apoptosis was reduced in the patients with AA as compared with AR patients and HS (P?<?0.05). Meanwhile, eosinophil chemotaxis and ROS generation markedly increased in the patients with AA 7 h and 24 h after challenge compared with other groups and baseline values (P?<?0.05). The percentage of apoptotic eosinophils in the patients with AA decreased at 7 h as well as 24 h after challenge when compared with other groups and the baseline values (P?<?0.05). There was a significant correlation between the migrated peripheral blood eosinophil count and the sputum eosinophil count (Rs?=?0.89, P?<?0.0001) and the sputum IL-5 level (Rs?=?0.68, P?=?0.002) at 24 h after bronchial challenge only in the patients with AA. Furthermore, the percentage of peripheral blood apoptotic eosinophils significantly correlated with eosinophil count in sputum (Rs?=?-0.53, P?=?0.02), and ROS production correlated with the serum IL-5 levels (Rs?=?0.71, P?=?0.01). CONCLUSION:During allergen-induced late-phase airway inflammation, peripheral blood eosinophils demonstrated further alterations of their functional activity manifested by enhanced spontaneous ROS production, increased chemotaxis, and diminished apoptosis in patients with AA.

Dataset Information

Assessment of peripheral airway function following chronic allergen challenge in a sheep model of asthma.

Background

Methodology/principal findings

Conclusions

Publications

Assessment of peripheral airway function following chronic allergen challenge in a sheep model of asthma.

Similar Datasets

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