New Approach to Equine Asthma TreatmentBy Kentucky Equine Research Staff · December 1, 2017
For horse owners, effectively managing equine asthma continues to be rife with frustration. Equine asthma, a designation that encompasses heaves, recurrent airway obstruction, or inflammatory airway disease, causes spasm, swelling, and remodeling of airways, coughing, nasal discharge, and poor performance. Common triggers of equine asthma include dust, mold spores, and mites, among other allergens.
Everyday management practices make avoidance of allergens next to impossible, according to one group of researchers*, and long-term treatment with medication comes with adverse side effects. Because of this, the researchers expressed a “great need for therapeutic concepts.”
Equine asthma is remarkably similar to human asthma. In human asthmatics, allergy avoidance has also proven to be an unsuccessful management strategy, forcing doctors to develop alternate treatment strategies. In two-legged sufferers, a technique called immunotherapy has gained favor.
“Immunotherapy essentially resets the T cells of the immune system to minimize the development of future asthma episodes,” explained Laura Petroski, B.V.M.S., a veterinarian at Kentucky Equine Research (KER).
In one study*, researchers used inhaled nanoparticles to help jump-start the immune systems of horses. Specifically, they sought to re-establish a normal balance between the type 1 and 2 helper T cells. As their name implies, nanoparticles are microscopic particles that appear to stimulate specific subclasses of T cells as well as anti-inflammatory cytokines (signaling molecules) that foster T-cell balance.
This type of immunotherapy does not require specialized equipment. “Horses simply breathe in the nanoparticles using commercially available inhalers,” described Petroski.
According to the researchers, both the “plain” nanoparticles as well as “loaded” nanoparticles with specific allergens (e.g., mold, rapeseed, fungi) bound to the inhaled particles can modulate the immune system, decreasing signs of asthma.
Twenty horses with asthma, nine of which were treated with plain nanoparticles and 11 treated with customized nanoparticles designed for their specific allergies, were used in the study. Horses were treated with the inhaled nanoparticles every other day for a total of seven treatments. Respiratory functions was assessed immediately before the study, immediately following the seventh treatment, and again six weeks after treatment.
Key findings of the study were:
- Both the plain and loaded nanoparticles resulted in clinical improvement of nasal discharge, breathing rate, amount and viscosity of nasal secretions directly after treatment and six weeks after treatment;
- No significant differences between the two treatments in clinical parameters were noted; and
- No difference in cytokine profiles [e.g., the anti-inflammatory interleukin 10 (IL-10) or IL-17] identified.
“Based on these results, the researchers concluded that nonspecific nanoparticle immunotherapy shows potential as a treatment for equine asthma, negating the need to identify and treat specific allergens,” shared Petroski.
She added, “Studies show that omega-3 fatty acids help horses with equine asthma. KER offers EO•3, which contains the omega-3 fatty acids DHA and EPA. This product is top-dressed onto the feed and helps horses with equine asthma, including heaves in older horses and inflammatory airway disease in young, athletic horses.”
*Klier, J., S. Geis, J. Steuer, et al. A comparison of nanoparticullate CpG immunotherapy with and without allergens in spontaneously equine asthma-affected horses, an animal model. Immunity, Inflammation and Disease. In press.