Évaluation du remodelage des voies respiratoires centrales de chevaux asthmatiques légers/modérés
Equine asthma is a common condition affecting horses of all ages. It is characterized by a lower airway non-septic inflammation. Although it is transient in most of the horses, asthma progress to its severe form in 15% of them. This last state is incurable and associated with periods of respiratory distress at rest. Remodeling of the lower airways is present in severe asthma. The alterations affect all airway components and correlate with the degree of airway obstruction of affected horses. Considering the lung function impairments in mild/moderate asthmatic horses, we postulated that a central airway remodeling is present and contributes to the disease progression. The structural changes affecting the central airways of 12 mild/moderate asthmatic horses and 10 aged-matched controls were studied using endobronchial biopsies and histomorphometric methods. The reliability of a fast-semi-quantitative score to identify morphological alterations of central airway was also evaluated. The histomorphometric method and the semi-quantitative scores permitted to identify the presence of epithelial hyperplasia, extracellular matrix thickened, and cellular infiltration in the lamina propria in asthmatic horses when compared to control horses. Two phenotypes of asthmatic horses could be defined: horses with epithelial hyperplasia associated to neutrophilic airway inflammation and with fibrosis of the muscular layer; and horses without epithelial hyperplasia with mast cell airway inflammation and normal muscle layer collagen deposition. It is the first study demonstrating the presence of central airway remodeling in mild/moderate asthmatic horses.
Horses Mild/moderate equine asthma Central airway Remodeling