Bian Fuqin, Ruan Guangfeng, Xu Jianhua, Wang Kang, Wu Juan, Ren Jiale, Chang Bingru, Ding Changhai
Department of Rheumatology and Immunology, Arthritis Research Institute, The First Affiliated Hospital of Anhui Medical University, Hefei, China.
Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia.
Int J Rheum Dis. 2020 Mar;23(3):435-442. doi: 10.1111/1756-185X.13787. Epub 2020 Jan 19.
The aim of this study was to investigate cross-sectional associations between serum levels of citrate and knee structural changes and cartilage enzymes in patients with knee osteoarthritis (OA).
A total of 137 subjects with symptomatic knee OA (mean age 55.0 years, range 34-74, 84% female) were included. Knee radiography was used to assess knee osteophytes, joint space narrowing (JSN) and radiographic OA assessed by Kellgren-Lawrence (K-L) grading system. T2-weighted fat-suppressed fast spin echo magnetic resonance imaging (MRI) was used to determine knee cartilage defects, bone marrow lesions (BMLs) and infrapatellar fat pad (IPFP) signal intensity alternations. Colorimetric fluorescence was used to measure the serum levels of citrate. Enzyme-linked immunosorbent assay was used to measure the serum cartilage enzymes including matrix metalloproteinase (MMP)-3 and MMP-13.
After adjustment for potential confounders (age, sex, body mass index), serum citrate was negatively associated with knee osteophytes at the femoral site, cartilage defects at medial femoral site, total cartilage defects, and total BMLs (odds ratio [OR] 0.17-0.30, all P < .05). Meanwhile, serum citrate was negatively associated with IPFP signal intensity alteration (OR 0.30, P = .05) in multivariable analyses. Serum citrate was significantly and negatively associated with MMP-13 (β -3106.37, P < .05) after adjustment for potential confounders. However, citrate was not significantly associated with MMP-3 in patients with knee OA.
Serum citrate was negatively associated with knee structural changes including femoral osteophytes, cartilage defects, and BMLs and also serum MMP-13 in patients with knee OA, suggesting that low serum citrate may be a potential indicator for advanced knee OA.
本研究旨在调查膝关节骨关节炎（OA）患者血清柠檬酸盐水平与膝关节结构变化及软骨酶之间的横断面关联。
共纳入137例有症状的膝关节OA患者（平均年龄55.0岁，范围34 - 74岁，84%为女性）。采用膝关节X线摄影评估膝关节骨赘、关节间隙狭窄（JSN）以及通过Kellgren-Lawrence（K-L）分级系统评估的放射学OA。采用T2加权脂肪抑制快速自旋回波磁共振成像（MRI）确定膝关节软骨缺损、骨髓病变（BMLs）和髌下脂肪垫（IPFP）信号强度改变。采用比色荧光法测量血清柠檬酸盐水平。采用酶联免疫吸附测定法测量血清软骨酶，包括基质金属蛋白酶（MMP）-3和MMP-13。
在对潜在混杂因素（年龄、性别、体重指数）进行调整后，血清柠檬酸盐与股骨部位的膝关节骨赘、股骨内侧部位的软骨缺损、总软骨缺损以及总BMLs呈负相关（比值比[OR] 0.17 - 0.30，均P <.05）。同时，在多变量分析中，血清柠檬酸盐与IPFP信号强度改变呈负相关（OR 0.30，P =.05）。在对潜在混杂因素进行调整后，血清柠檬酸盐与MMP-13呈显著负相关（β -3106.37，P <.05）。然而，在膝关节OA患者中，柠檬酸盐与MMP-3无显著关联。
血清柠檬酸盐与膝关节结构变化（包括股骨骨赘、软骨缺损和BMLs）以及膝关节OA患者的血清MMP-13呈负相关，提示低血清柠檬酸盐可能是晚期膝关节OA的一个潜在指标。
