Relationship between biomarkers of cartilage in serum and degenerative joint disease in lusitanian horses

Cartilage degradation biomarkers are a potential tool for early diagnosis of degen- erative joint disease (DJD). In young horses, Coll2-1 and Coll2-1NO2 have been studied in serum and reported to be useful in the assessment of joint disease. Fib3-2 has been described to be higher in serum of humans with osteoarthritis but has not been assessed in horses. The aim of the current study was to evaluate biomarkers’ changes with age, sex, and exercise and correlate them with DJD. Blood collection and radiographic examination were performed in 51 Lusitanian horses. Moreover, inertial sensor-based detection of lameness was used to assess pain together with sub- jective examination. Females presented significantly higher concentrations of Coll2- 1 (P5.015) and Coll2-1NO2 (P5.014) compared to males. We found significant influence of high level of work in lower concentration of Coll2-1 (P5.001) and sig- nificant influence of sex in concentration of Coll2-1NO2 (P5.030). There was no influence of sex, age and work on Fib3-2. All biomarkers were increased in the DJD group (n535) compared to healthy controls (n516). This difference was significant for Coll2-1 (P5.015). When sorted by sex and age groups, significant difference in Coll2-1 between disease and healthy controls disappeared in old horses and females. Coll2-1 is a good marker of cartilage degradation in horses with DJD, being more specific in young horses and males. Fib3-2 may be further explored to help identify disease in particular cases.