BACKGROUND Osteoarthritis (OA) of the distal intertarsal (DIT) and tarsometatarsal (TMT) joints occurs commonly. Synovial fluid (SF) biomarkers of collagen and bone turnover have potential clinical value. OBJECTIVES To measure SF biomarker concentrations from DIT and TMT joints in adult horses and determine if they correlate with radiographic OA severity and are higher in joints with radiographic OA compared to controls. STUDY DESIGN Cross-sectional. METHODS Radiographic OA of DIT and TMT joints was evaluated from adult horses (5-35 years old). Overall radiographic scores divided horses into those with mild or moderate radiographic OA (16 joints from 9 horses) or controls (13 joints from 9 horses). Direct biomarkers of OA (Carboxypropeptide of type II collagen = CPII, carboxy-neoepitope of type II collagen exposed after collagenase-cleavage = C2C, Bone alkaline phosphatase = BAP and Chondroitin sulfate epitope = CS846) were measured via ELISA and CPII/C2C was calculated. Biomarkers were correlated with radiographic findings and concentrations from those with radiographic OA to control joints and were compared. RESULTS Concentrations of CPII (R = 0.84, P<0.001), C2C (R = 0.69, P<0.001) and BAP (R = 0.41, P = 0.03) as well as CPII/C2C (R = 0.69, P<0.001) values positively correlated with overall radiographic scores. Adjusted means ± s.d., after controlling for age, for CPII (P<0.001), C2C (P<0.001), CPII/C2C (P = 0.004) and BAP (P = 0.05) were significantly higher in DIT and TMT joints with radiographic OA (CPII: 2174.45 ± 1064.01; C2C: 233.52 ± 51.187; CPII/C2C: 9.01 ± 4.09; BAP: 21.98 ± 15.34) compared to controls (CPII: 594.53 ± 463.05; C2C: 153.12 ± 48.95; CPII/C2C: 3.96 ± 2.38; BAP: 12.76 ± 3.61). CPII (P<0.001), C2C (P = 0.001) and CPII/C2C (P = 0.001) were significantly higher with moderate radiographic OA (CPII: 2444.61 ± 772.78; C2C: 248.90 ± 44.94; CPII/C2C: 9.47 ± 2.97) compared to controls (CPII: 658.38 ± 417.36; C2C: 156.49 ± 47.61; CPII/C2C: 4.15 ± 2.04), with CPII also showing significantly higher concentrations (P = 0.04) with mild radiographic OA compared (1515.00 ± 584.95) to controls (658.38 ± 417.36). There were no differences in CS846 concentrations between radiographic OA and control joints. Age positively correlated with CPII (R = 0.48, P = 0.01) and C2C (R = 0.44, P = 0.02) concentrations. MAIN LIMITATIONS Radiographic OA was assessed, not clinical lameness. Controls were not age-matched to those with spontaneous radiographic OA. CONCLUSIONS There is an association between collagen (CPII, C2C and CPII/C2C) and bone (BAP) biomarkers and radiographic OA in the distal tarsal joints of horses.

中文翻译：

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马远端跗关节中胶原蛋白和骨生物标志物与放射学骨关节炎之间的关联。

背景技术远端跗骨（DIT）和跗跖骨（TMT）关节的骨关节炎（OA）常见。胶原蛋白和骨转换的滑液 (SF) 生物标志物具有潜在的临床价值。目的 测量成年马 DIT 和 TMT 关节的 SF 生物标志物浓度，并确定它们是否与放射学 OA 严重程度相关，并且与对照组相比，放射学 OA 的关节是否更高。研究设计横截面。方法 对成年马（5-35 岁）进行 DIT 和 TMT 关节的放射影像学 OA 评估。总体射线照相评分将马分为轻度或中度射线照相OA（9匹马的16个关节）或对照组（9匹马的13个关节）。OA 的直接生物标志物（II 型胶原的羧基前肽 = CPII，通过 ELISA 测量胶原酶裂解后暴露的 II 型胶原的羧基新表位 = C2C、骨碱性磷酸酶 = BAP 和硫酸软骨素表位 = CS846) 并计算 CPII/C2C。生物标志物与放射学检查结果和放射学 OA 患者的浓度相关，以控制关节并进行比较。结果 CPII (R = 0.84, P<0.001)、C2C (R = 0.69, P<0.001) 和 BAP (R = 0.41, P = 0.03) 以及 CPII/C2C (R = 0.69, P<0.001) 的浓度值与整体放射学评分呈正相关。调整后的平均值 ± sd，在控制年龄后，CPII (P<0.001)、C2C (P<0.001)、CPII/C2C (P = 0.004) 和 BAP (P = 0.05) 在 DIT 和 TMT 关节中显着更高OA（CPII：2174.45 ± 1064.01；C2C：233.52 ± 51.187；CPII/C2C：9.01 ± 4.09；BAP：21.98 ± 15。34）与对照组相比（CPII：594.53 ± 463.05；C2C：153.12 ± 48.95；CPII/C2C：3.96 ± 2.38；BAP：12.76 ± 3.61）。CPII (P<0.001)、C2C (P = 0.001) 和 CPII/C2C (P = 0.001) 显着高于中度放射学 OA (CPII: 2444.61 ± 772.78; C2C: 248.90 ± 44.94; CPII/C2C: 9.47 ± 2.97)与对照组相比（CPII：658.38 ± 417.36；C2C：156.49 ± 47.61；CPII/C2C：4.15 ± 2.04），与对照组相比（1515.00 ± 584.95），CPII 也显示出显着更高的浓度（P = 0.04），轻度放射学 OA（1515.00 ± 584.95） 658.38 ± 417.36）。放射学 OA 和对照关节之间的 CS846 浓度没有差异。年龄与 CPII (R = 0.48, P = 0.01) 和 C2C (R = 0.44, P = 0.02) 浓度呈正相关。主要局限 评估了影像学 OA，而不是临床跛行。对照组与自发性放射学 OA 的年龄不匹配。结论 在马的远端跗关节中，胶原蛋白（CPII、C2C 和 CPII/C2C）和骨（BAP）生物标志物和放射学 OA 之间存在关联。