Plasma and Synovial Fluid Cell-Free DNA Concentrations Following Induction of Osteoarthritis in Horses.
Authors: Panizzi Luca, Dittmer Keren E, Vignes Matthieu, Doucet Jennie S, Gedye Kristene, Waterland Mark R, Rogers Chris W, Sano Hiroki, McIlwraith C Wayne, Riley Christopher B
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Cell-Free DNA as an Osteoarthritis Biomarker in Horses Early diagnosis of equine osteoarthritis remains challenging despite advances in imaging and clinical assessment, prompting researchers to investigate novel synovial biomarkers that could detect disease before significant cartilage damage occurs. Panizzi and colleagues induced unilateral carpal OA in nine Thoroughbred fillies whilst eight underwent sham surgery, then measured cell-free DNA (cfDNA) concentrations in both synovial fluid and plasma samples collected weekly over nine weeks using fluorometry. Synovial fluid cfDNA proved significantly elevated in OA joints compared to sham joints by day 28 (median 1430 µg/L versus 631 µg/L) and remained elevated at day 63 (1537 µg/L versus 606 µg/L), whereas plasma cfDNA showed no meaningful differences between groups at any timepoint. For equine practitioners, this work suggests synovial fluid cfDNA warrants further development as a prognostic indicator of early OA progression, though its utility would necessarily be limited to joints accessible via arthrocentesis. The finding that plasma cfDNA lacks diagnostic sensitivity underscores the need for joint-derived samples when investigating joint-specific pathology, reinforcing the value of synovial fluid analysis over systemic biomarkers for monitoring joint disease in individual horses.
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Practical Takeaways
- •Synovial fluid cfDNA could potentially help clinicians identify and monitor early OA progression in horses, providing a novel diagnostic tool when traditional markers lack sensitivity
- •Plasma cfDNA measurement alone is not reliable for OA diagnosis in horses—synovial fluid sampling is necessary, which may limit practical clinical application due to the invasive nature of joint taps
- •This biomarker approach offers a cost-effective alternative to some existing diagnostics and may enable earlier intervention before significant cartilage damage occurs
Key Findings
- •Synovial fluid cfDNA concentrations were significantly higher in OA joints compared to sham-operated joints on Day 28 (1430 μg/L vs 631 μg/L, p=0.017) and Day 63 (1537 μg/L vs 606 μg/L, p=0.021)
- •Plasma cfDNA showed no significant differences between OA and sham groups after carpal OA induction, indicating insufficient sensitivity for diagnostic purposes
- •Synovial fluid cfDNA measurement may serve as a biomarker to monitor early disease progression in horses with osteoarthritis