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Reversing Asthma-Related Changes in Horse's LungsBy Kentucky Equine Research Staff · October 4, 2017

Inhaled corticosteroid anti-inflammatory drugs such as fluticasone and β2-agonists help horses during asthmatic flare-ups*. According to a recent study, not only do these medications help with asthma, they also help reverse the detrimental changes in the actual structure of the airways**.

“Equine asthma is characterized by the influx of certain white blood cells, called neutrophils, into the walls of the horse’s airway, causing inflammation. In addition, the muscle cells that control the diameter of the airway enlarge, thereby obstructing the airways,” explained Laura Petroski, D.V.M., of Kentucky Equine Research (KER).

Being able to reverse the changes characteristic of asthma returns the airways to a more normal structure, decreases clinical signs associated with disease (increased respiratory effort, coughing, development of a heaves line), and improves both athletic function and quality of life.

In a recent study*, various treatment options were tested to determine which reversed asthma-related changes. Horses diagnosed with severe asthma were treated with one of four strategies: fluticasone alone, salmeterol alone, a combination of fluticasone and salmeterol, or “allergen avoidance.” After 12 weeks, the researchers found:

  • Fluticasone and fluticasone/salmeterol both significantly decreased smooth muscle remodeling by approximately 30%;
  • Only fluticasone/salmeterol decreased remodeling of other regions of the airway walls (e.g., extracellular space between individual cells in the wall of the airways); and
  • Only fluticasone/salmeterol decreased the influx of neutrophils that contribute to airway inflammation.

This study supports the hypothesis that reversal of airway remodeling in asthmatics can potentially be achieved, though may require long-term administration of relatively high doses of drugs.

“In addition to pharmaceutical drugs, the most up-to-date consensus statement on equine asthma also recommends environmental changes, allergen avoidance, and supplementation with fish oil,” reminded Petroski.

She added, “KER offers EO•3, a potent marine-derived oil rich in the omega-3 fatty acids DHA and EPA.”

Need a refresher on other suggested strategies for managing equine asthma? Check out these eight important tips to help jump-start your new routines.

*Couëtil, L.L., J.M. Cardwell, V. Gerber, et al. 2016. Inflammatory airway disease of horses—Revised  consensus statement. Journal of Veterinary Internal Medicine. 30(2):503-515.

**Bullone, M., A. Vargas, Y. Elce, et al. 2017. Fluticasone/salmeterol reduces remodelling and neutrophilic inflammation in severe equine asthma. Scientific Reports. 7(1):8843.