Correlation Of Dickkopf-1 Concentrations In Plasma And Synovial Fluid To The Severity Of Radii Graphic Signs Of Equine Osteoarthritis

Objective: The purpose of this study was to determine whether there was a correlation between circulating and intra-synovial Dkk-1 and radiographic signs of equine osteoarthritis.Methods: Circulating and intra-synovial Dkk-1 levels were measured in clinical cases using a commercially available human Dkk-1 ELISA. Radiographs were performed of the joints from which fluid was collected and these were assessed and scored by a boarded radiologist for joint narrowing, subchondral bone sclerosis, subchondral bone lysis, and periarticular modelling. Comparisons were made between radiographic scores and the concentrations of Dkk-1 using a Kruskal-Wallis one-way ANOVA. Correlations were calculated using Kendall's statistic.Results: A total of 42 synovial fluid samples from 21 horses were collected and used in the analysis. No significant correlation was identified between Dkk-1 concentrations and radiographic signs of osteoarthritis. Intrasynovial Dkk-1 concentrations were significantly greater (p < 0.001) in low motion joints (mean concentration, 232.68 pg/mL; range, 109.07-317.17) when compared to high-motion joints (28.78 pg/mL; 0.05-186.44 pg/mL) (p < 0.001).Clinical significance: Low motion joints have significantly higher concentrations of Dkk-1 compared to high motion joints. Further research is needed to establish the importance of this finding and whether potential diagnostic or therapeutic applications of Dkk-1 exist in the horse.