Equine recurrent uveitis (ERU) is the most common cause of blindness in horses and is believed to affect approximately 10% of the equine population. The exact cause of ERU remains unclear, although researchers have shown that recurrent bouts of inflammation involving activated T-cells (cells largely responsible for cell-mediated immunity) lead to destruction of the retina.
In an effort to find ways to monitor development of ERU and predict an approaching relapse, Cornelia Deeg and colleagues from the Ludwig-Maximilians University in Munich, Germany, attempted to identify "biomarkers" of ERU in the blood of affected horses.
The research team collected blood from 20 ERU horses and 20 healthy control horses and removed the small population of highly abundant proteins.This enabled the researchers to then compare the relative concentrations of the remaining serum proteins between the two groups of horses.
The two groups had differing concentrations of 10 serum proteins, including kininogen. Specifically, the researchers found significantly lower blood concentrations of this protein in ERU horses as compared to control horses.
According to the authors, kininogen has "multiple physiological functions, with an important role in inflammation and promoting neovascularization (formation of new blood vessels)."
"Since neovascularization plays a major role in the pathogenesis of uveitis (the cellular, biochemical, and pathological mechanisms underlying its development), the identification of a proangiogenic (promoting the growth of new blood vessels from pre-existing vessels) factor in the retina presents an important finding and may contribute to the elucidation of the pathogenesis of uveitis," the authors concluded.
The study, "Kininogen is decreased in peripheral blood stream but increased in target tissue of autoimmune uveitis," is scheduled to be published in an upcoming edition of the journal Investigative Ophthalmology & Visual Science. The abstract is available on PubMed.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.