“Characterizing Nasal T Cell Populations in Equine Herpesvirus Type 1 (EHV-1) Immune and Susceptible Horses”

Equine herpesvirus type 1 (EHV-1) is a highly prevalent respiratory pathogen of the horse, which has devastating impact on horse health and the economy of the industry. Prior work suggests that the magnitude of EHV-1 specific T cell populations prior to infection are a positive indicator of protection, however this has been focused on systemic rather than the local nasal T cell population. T cells can be found within the mucus, the epithelial layer, and nasal associated lymphoid tissue (NALT), where they can detect antigen and initiate an adaptive response. Here the researchers will seek to investigate the frequency of T cell populations in the nose of the horse and their responsiveness to EHV-1 exposure. Robust mucosal immunity at the site of infection can reduce viral entry into the tissue. This will give a first look into the T cell populations found within the nose and determine if they can contribute to immunity upon EHV-1 exposure.

Young Investigator Award: Camille Holmes, Graduate Student

Mentor/Advisor: Bettina Wagner DVM

“An EHV-1 mRNA-based Vaccine Delivered in Extracellular Vesicles”

Equine herpesvirus-1 (EHV-1) is known to cause respiratory disease in young horses, abortion in pregnant mares, and neurologic disease in mature horses. An increasing need to improve vaccines for protection against the neurologic disease associated with this virus has caused researchers to hypothesize construction of alternative mRNA-based vaccination methods as seen in related human herpesvirus infections. The proposed vaccination method could elicit prophylactic or broad-range immunity and offers a lower cost option approach for future vaccine development.

Principal Investigator Award: Brett Sponseller DVM, PhD

“Bile Acid Profiling of Pyloric Gastric Fluid and Serum in Horses with and without Equine Glandular Gastric Disease”

Gastric ulcers are a common disease of performance horses that can be associated with decreased performance or signs of gastrointestinal (GI) disturbance including colic, decreased appetite, behavior changes, and weight loss. Gastric ulcers may occur in either the glandular or squamous portion of the stomach. Little is known about mechanisms underlying glandular ulcers. Prevalence of glandular ulcers in Quarter Horses is not known. Treatment of glandular ulcers can be more prolonged and expensive when compared to treatment of squamous ulcers, with cost for

evaluation and treatment of the average Quarter Horse estimated at $4,000. The role of bile acid reflux as a factor in development of glandular ulcers has yet to be investigated. In this study horses will undergo endoscopy to assess for evidence of glandular ulcers. Samples of gastric fluid and blood will be collected for bile acid measurements. The bile acid profile of each sample will be analyzed and compared between horses with and without evidence of glandular ulcers. Detection of differences in bile acid profiles may allow for future therapies.

Young Investigator Award: Linda Paul DVM

Mentor/Advisor: Heidi Banse DVM, PhD, Frank Andrews DVM, Aaron Ericsson DVM, PhD

“Stress-induced Clodronate Release to Peak Exercise Training or Bone Insult following Repetitive Administration in Young Horses”

In 2014, the FDA approved bisphosphonate drugs in horses ≥4 years for the treatment of navicular disease. The perceived benefits in horses with degenerative bone disease, however, this has resulted in its off-label use in horses with normal skeletal remodeling for short-term analgesic effects and to enhance bone formation. Consequently, the long-term implications are beginning to plague the industry. Further, a rise in positive tests for clodronate has resulted in disqualification and imposed trainer penalties. Because of clodronate’s affinity for bone and long half-life, clodronate detection up to months post-treatment is due to acute stress or bone insult. The use of this class of drug for manipulation of normal bone development in juvenile animals undergoing forced exercise poses a significant risk to the welfare of the American Quarter Horse and has yet to be investigated or approved by the FDA. The proposed work is in conjunction with an expansive study funded by USDA-NIFA to generate the largest dataset regarding the effects of bisphosphonate use in skeletally immature, exercising horses. The overarching goal of the proposed study is to be the first in any species to determine clodronate re-release in response to controlled stressors, which is the necessary first step in optimizing its use and regulation in American Quarter Horse athletes.

Principal Investigator: Amanda Bradbery PhD

Texas A&M University ($74,620.00)

“Response of Healthy Joints to Intra-articular Corticosteroids in Young, Exercising Horses”

Early training and exercise are critical for young horses intended for sales or futurities. Throughout the training period, young horses undergo increasing and repeated stress to joints culminating in excess production of inflammatory mediators that result in impaired athletic performance. In response, owners of young horses in training frequently seek administration of intra-articular corticosteroids (IAC). Despite their widespread use, controversy surrounds their use. There is a critical gap in knowledge surrounding the welfare and biological impacts in young horses in training. The proposed experiment evaluates direct and indirect biomarkers of cartilage metabolism, inflammation, and pain perception in young exercising horses. Data collected from the proposed study will effectively contribute to the protection of competition integrity, by reducing the risk of musculoskeletal injury, and will answer key questions regarding enhanced performance longevity for young horses in an effort to improve the health and welfare of the American Quarter Horse.

Principal Investigator: Jessica Lucia Leatherwood PhD

“Three-dimensional Finite Element Simulations of Equine Traumatic Brain Injury following Trauma”

Traumatic Brain Injury (TBI) typically results from impact to the head through acceleration-deceleration forces accompanying vigorous “whip-lash”: head movements, which can result in severe injury including death. The most common and potentially most dangerous type of injury which can occur is when a horse flips over backwards and strikes its poll. Although therapies for Tin horses have been extrapolated from human medicine, there is little research to date to minimize TBI risk. In humans, computer modeling and simulation (finite element analysis, FEA) is used in the study of head impacts to design helmets which have massively reduced the impact of TBI in people. The aim of this study is to conduct FEA of head injury in the horse with a view to developing a suitable device (helmet), thus targeting a preventative approach based on the AQHF Refrigerator Fund guidelines. To advance the TBI study in Quarter Horses, this group has assembled a multi-disciplinary team using experts in equine neurological trauma, a human FEA TBI brain specialist and the PI who has experience in equine 3D modelling.

Principal Investigator: Adam Biedrzycki DVM, PhD

For more information on the American Quarter Horse Foundation’s equine research program, please contact us at: American Quarter Horse Foundation Equine Research Program PO Box 32111 Amarillo, TX 79120 aqha.com/foundation (806) 378-5034 phone (806) 376-1005 fax foundation@aqha.org