Using Immunomodulatory Therapy for Equine Asthma

Equine asthma, dubbed a “disease of domestication” due to the preponderance of affected stabled horses, remains one of the most significant allergic diseases of the respiratory tract, according to German veterinary researchers.* Despite the availability of updated treatment guidelines for equine asthma, all of the recommendations in that report address only symptoms and not underlying causes.

“Corticosteroids, bronchodilators, and omega-3 fatty acids all help control equine asthma, yet none actually cures the disease,” Kathleen Crandell, Ph.D., a Kentucky Equine Research nutritionist explained.

With over 50 different types of allergens found in hay and straw dust alone, in addition to certain horses having a genetic predisposition to asthma, controlling this condition can be frustrating, especially when it limits the use of horses and compromises quality of life.

Rather than finding ways to control equine asthma, researchers are looking at ways to restore the horse’s unruly immune system to normal and cure, not treat, the underlying cause. One potential way to achieve this goal is by administering inhaled nanoparticles that deliver an immunomodulator, an agent capable of modifying the action of the immune system. In the case of equine asthma, the immunomodulator is cytosine-phosphate-guanosine oligodeoxynucleotides (CpG-ODNs).

Previous research revealed that these inhaled nanoparticles activate regulatory T cells and restore T helper cell balance, both of which boost immunity. Building on that research, CpG-ODNs were administered to horses, and their response to therapy was assessed.

“A single daily dose of the nanoparticles for 10 days resulted in a significant improvement in all evaluated parameters, including clinical signs of disease and bronchoalveolar lavage, or lung wash, fluid analysis and other laboratory parameters,” summarized Crandell.

She added, “These improvements in asthma were impressive compared to pretreatment values and compared to horses treated with the inhaled corticosteroid beclomethasone.”

While awaiting commercial availability of this novel asthma therapy, owners are encouraged to embrace the lifestyle changes and medication recommendations that ameliorate symptoms of asthma. These include administration of omega-3 fatty acids, such as Kentucky Equine Research’s EO-3.

“EO-3 is a marine-derived oil rich in the omega-3 fatty acids EPA and DHA. Each 30-mL serving provides almost 10,000 mg of omega-3 fatty acids ready to exert their natural anti-inflammatory effects to help horses with equine asthma,” Crandell shared.

*Klier, J., C. Bartl, S. Geuder, et al. Immunomodulatory asthma therapy in the equine animal model: A dose-response study and evaluation of a long-term effect. Immunity, Inflammation and Disease. In press.