Severe asthma is associated with a remodeling of the pulmonary arteries in horses.
Authors: Ceriotti Serena, Bullone Michela, Leclere Mathilde, Ferrucci Francesco, Lavoie Jean-Pierre
Journal: PloS one
Summary
# Severe Equine Asthma and Pulmonary Artery Remodelling: Structural Changes Beyond Airway Inflammation Pulmonary hypertension commonly develops in horses with severe asthma, yet oxygen therapy only partially reverses this complication, suggesting mechanisms beyond simple hypoxic vasoconstriction are at work. Ceriotti and colleagues investigated whether structural remodelling of pulmonary arteries—a recognised feature in human chronic obstructive pulmonary disease—occurs in equine asthma by measuring arterial wall thickness and smooth muscle mass across different lung regions in asthmatic and control horses, then reassessing these changes after one year of either antigen avoidance or inhaled fluticasone treatment. Asthmatic horses demonstrated significantly increased pulmonary artery wall area and smooth muscle mass, predominantly in apical and caudodorsal lung regions, findings that persisted even during clinical remission. Whilst both antigen avoidance and inhaled corticosteroids reduced arterial wall area, only the avoidance strategy showed a trend towards normalisation of vascular smooth muscle mass, suggesting genuine reversal of remodelling rather than merely symptom suppression. This work implies that narrowed, thickened pulmonary arteries in asthmatic horses amplify hypoxic vasoconstriction and contribute to cor pulmonale development—emphasising that comprehensive management should prioritise environmental control and antigen elimination alongside, or perhaps ahead of, pharmacological approaches alone.
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Practical Takeaways
- •Severe asthma causes structural remodeling of lung blood vessels that contributes to pulmonary hypertension; managing this requires attention to long-term vascular changes, not just acute symptoms
- •Prioritize antigen avoidance (improved stabling, hay quality, dust control) over or alongside inhaled corticosteroids, as avoidance appears more effective at reversing the smooth muscle changes driving pulmonary hypertension
- •Horses with severe asthma need at least 1 year of consistent antigen avoidance to potentially reverse vascular remodeling; expect gradual rather than rapid improvement
Key Findings
- •Pulmonary arteries in asthmatic horses show increased wall area and smooth muscle mass in apical and caudodorsal lung regions, present in both exacerbation and remission phases
- •Antigen avoidance strategy reversed both increased wall area and showed a trend toward normalization of vascular smooth muscle mass
- •Inhaled fluticasone reversed increased wall area but did not normalize vascular smooth muscle mass, unlike antigen avoidance alone
- •Pulmonary artery remodeling with smooth muscle proliferation may amplify hypoxic vasoconstriction, contributing to pulmonary hypertension development in severe asthma