PT - JOURNAL ARTICLE AU - Michela Bullone AU - Mireille Godbout AU - James G. Martin AU - Jean-Pierre Lavoie TI - Endobronchial ultrasonography detects subepithelial remodeling in large airways of asthmatic horses DP - 2014 Sep 01 TA - European Respiratory Journal PG - P4975 VI - 44 IP - Suppl 58 4099 - http://erj.ersjournals.com/content/44/Suppl_58/P4975.short 4100 - http://erj.ersjournals.com/content/44/Suppl_58/P4975.full SO - Eur Respir J2014 Sep 01; 44 AB - Heaves is a naturally-occurring asthma-like disease of horses. Increased smooth muscle (ASM) and extracellular matrix (ECM) mass have been detected in airways of asthmatic man and horses. Assessment of ASM and ECM remodeling in vivo is still problematic, as endobronchial biopsies often provide incomplete sampling of the bronchial wall. Endobronchial ultrasonography (EBUS) allows non-invasive evaluation of large airway structures in man and in isolated equine lungs, as we have already shown ex vivo.We now hypothesize that in vivo EBUS can differentiate horses with heaves from controls based on the thickness of ASM and ECM layer.EBUS was performed in 4 horses with heaves and 3 controls under sedation using a 30 MHz radial probe. Horses were then humanely euthanized for reasons other than respiratory conditions. Ten randomly chosen cartilaginous bronchi were harvested at necropsy from the lungs of all animals and processed for histology. Internal airway perimeter (Pi), thickness of the epithelium (L1), combined ECM and ASM layers (L2) and L2 area were measured on EBUS images. The equivalent structures were measured on histological sections.A significant increase in L2 thickness and normalized L2 area (AL2/Pi2) were detected in central airways of horses with heaves compared to controls (p<0.05). Results were confirmed histologically as ASM mass and ECM components were increased in the large airways of heaves-affected horses compared to controls (p<0.05). Therefore, EBUS allows in vivo evaluation of bronchial remodeling affecting large airway submucosal structures in horses and could be used to monitor airway remodeling non-invasively in interventional studies in this species.