One of the key players in many equine orthopedic diseases is inflammation – a duel-edged sword essential for healing, but detrimental when it goes unchecked. In fact, many of the most devastating illnesses affecting horses have their origin in persistent and excessive inflammatory responses leading to irreversible tissue damage.
Inflammation is one way the equine immune system responds to injuries and trauma. It also helps the body isolate foreign bacteria and other toxic substances from further contact with body tissues. Damaged or diseased tissue send out signals which recruit pro-inflammatory substances and special cells to the area. The end result is the elimination of infectious agents, as well as diseased and dead tissue, and the initiation of the healing process.
Horses have ways to dampen and control inflammation to prevent the process from getting out of control and damaging healthy tissue. However, sometimes their bodies do a poor job reining in inflammation once it gets going. Just like wildfires that start to roar out of control, the inflammatory response can overwhelm the body’s ability to stop it. Even if the main “fire” is extinguished, low-grade inflammation can become chronic, like undetectable hot spots in wildfires. This persistent condition can contribute to diseases as diverse as heart disease, metabolic syndrome, and cancer.
One of the inflammatory response cells that come to the rescue, but also can be responsible for much of the damage, is a type of white blood cell called a neutrophil. Neutrophils are the “workhorse” of the immune system, and are the most common type of white blood cell found in almost all animals, including horses. Neutrophils are recruited to sites of inflammation where they participate in the killing of infectious agents and the cleaning up of cellular debris. However, too many neutrophils showing up for the job can cause serious health complications.
Morris Animal Foundation currently is funding a group of scientists at North Carolina State University who have been looking at neutrophil behavior in horses for the last decade. The team is studying how neutrophils are activated and how they are regulated. One result of the team’s painstaking research was the discovery of how a specific protein influences neutrophil activation – and, more importantly, the team showed they were able to block damaging inflammation by over-compensating neutrophils with a pharmaceutical compound.
The team now is working to move this compound to therapeutic trials as well as looking at another commonly used anti-ulcer drug for anti-inflammatory properties. If successful, results of both studies could significantly improve a veterinarian's ability to treat inflammatory disease and improve the quality of life for horses suffering from orthopedic and many other detrimental equine health diseases and conditions.