Neurophenotypes in airway diseases: insights from translational cough studies
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Accepted version
Accepted version
Author(s)
Type
Journal Article
Abstract
Rationale: Most airway diseases, including chronic obstructive pulmonary disease (COPD), are associated with excessive coughing. The extent to which this may be a consequence of increased activation of vagal afferents by pathology in the airways (e.g. inflammatory mediators, excessive mucus) or an altered neuronal phenotype is unknown. Understanding whether respiratory diseases are associated with dysfunction of airway sensory nerves has the potential to identify novel therapeutic targets. Objectives: To assess the changes in cough responses to a range of inhaled irritants in COPD, and model these in animals to investigate the underlying mechanisms. Methods: Cough responses to inhaled stimuli in patients with COPD, healthy smokers, refractory chronic cough, asthma and healthy volunteers were assessed and compared with vagus/airway nerve and cough responses in a cigarette smoke (CS) exposure guinea-pig model. Measurements and Main Results: Patients with COPD had heightened cough responses to capsaicin but reduced responses to PGE2 compared with healthy volunteers. Furthermore, the different patient groups all exhibited different patterns of modulation of cough responses. Consistent with these findings, capsaicin caused a greater number of coughs in CS-exposed guinea-pigs than in controls; similar increased responses were observed in ex-vivo vagus nerve and neuron cell bodies in the vagal ganglia. However, responses to PGE2 were decreased by CS-exposure. Conclusions: CS exposure is capable of inducing responses consistent with phenotypic switching in airway sensory nerves comparable to the cough responses observed in patients with COPD. Moreover, the differing profiles of cough responses support the concept of disease-specific neuro-phenotypes in airway disease.
Date Issued
2016-06-15
Date Acceptance
2016-01-07
Citation
American Journal of Respiratory and Critical Care Medicine, 2016, 193 (12), pp.1364-1372
ISSN
1535-4970
Publisher
American Thoracic Society
Start Page
1364
End Page
1372
Journal / Book Title
American Journal of Respiratory and Critical Care Medicine
Volume
193
Issue
12
Copyright Statement
© 2016 American Thoracic Society. All Rights Reserved.
Sponsor
Medical Research Council (MRC)
Medical Research Council (MRC)
North West Lung Centre
IP2IPO Innovations Limited
Grant Number
MR/K020293/1
PO 75415839
n/a
7112
Subjects
COPD
asthma
cough
guinea pig
vagus nerve
Publication Status
Published
Date Publish Online
2016-01-07