Horses With Pasture Asthma Have Airway Remodeling That Is Characteristic of Human Asthma.
Authors: Ferrari Claudenir R, Cooley Jim, Mujahid Nisma, Costa Lais R, Wills Robert W, Johnson Melanie E, Swiderski Cyprianna E
Journal: Veterinary pathology
Summary
# Editorial Summary: Airway Remodeling in Equine Pasture Asthma Researchers compared lung tissue from 15 horses with pasture asthma (formerly summer pasture RAO) and 9 controls to determine whether the histopathological changes mirror those seen in human asthma. Using standardised scoring of hematoxylin and eosin and Movat's pentachrome-stained airway sections, they quantified six key remodelling features and identified a novel pattern of terminal bronchiolar disorganisation unique to diseased airways. Diseased airways showed markedly elevated smooth muscle mass (2.5-fold), goblet cell hyperplasia (37.6-fold), peribronchiolar fibrosis and elastic fibre proliferation, alongside significantly greater mucus occlusion and adventitial inflammation compared to healthy controls. A striking finding was terminal bronchiolar remodelling—a complex tissue disorganisation occurring at sites of presumed air trapping—which was 3.7 times more common in affected horses and distributed heterogeneously across lung lobes, paralleling the non-uniform pathology of human asthma. Older horses (>15 years) showed independent risk factors for accelerated fibrotic remodelling, suggesting a progressive disease phenotype. This work positions equine pasture asthma as a uniquely valuable translational model for human asthma research, offering naturally occurring disease pathology that spontaneous animal models have failed to replicate—a significant advantage for investigating both disease mechanisms and therapeutic interventions.
Read the full abstract on PubMed
Practical Takeaways
- •Pasture asthma involves genuine structural airway remodeling similar to human asthma, not just inflammation—this may require long-term management strategies beyond acute treatment.
- •Older horses (>15 years) with pasture asthma likely have more advanced airway fibrosis and remodeling, potentially affecting prognosis and response to therapy.
- •Equine pasture asthma represents a naturally occurring disease model valuable for understanding human asthma pathophysiology and developing translational treatments.
Key Findings
- •Pasture asthma-affected horses demonstrated significantly greater airway smooth muscle thickening (OR=2.5), goblet cell hyperplasia (OR=37.6), peribronchiolar fibrosis (OR=3.8), and elastic system fiber changes (OR=4.2) compared to controls.
- •A novel terminal bronchiolar remodeling pattern was overrepresented in diseased airways (OR=3.7) and corresponded to putative air-trapping sites similar to human asthma.
- •Age >15 years was an independent risk factor for increased peribronchiolar fibrosis, elastic fibers, and terminal bronchiolar remodeling.
- •Equine pasture asthma replicates human asthma airway remodeling patterns more faithfully than induced animal models, supporting its translational research value.