Department of Internal Medicine, Ribeirão Preto Medical School, University of São Paulo, Avenida dos Bandeirantes 3900, Campus Universitário Monte Alegre, Ribeirão Prêto, SP, 14048-900, Brazil.
Department of Oral Surgery, Pathology and Clinical Dentistry, School of Dentistry, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
Adv Rheumatol. 2023 Mar 15;63(1):13. doi: 10.1186/s42358-023-00294-3.
In chronic arthropathies, there are several mechanisms of joint destruction. In recent years, studies have reported the implication of receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) in the process of activation and differentiation of osteoclasts, a key cell in the development of bone erosion. The RANKL/OPG ratio is increased in the serum of patients with malignant diseases and lytic bone disease, as well as rheumatoid arthritis (RA). The objective of this study was to measure and compare the concentrations of OPG and RANKL in the synovial fluid (SF) of patients with rheumatoid arthritis, spondyloarthritis (SpA) and osteoarthritis (OA).
This was an observational and cross-sectional study with 83 patients, 33 with RA, 32 with SpA and 18 with OA, followed up regularly in the outpatient clinics of the Rheumatology Department of the Clinics Hospital of the Ribeirão Preto Medical School-USP. All patients were assessed for indications for arthrocentesis by the attending physicians at the time of SF collection and were evaluated for demographic variables and medication use. Disease activity was assessed in individuals with RA and SpA. The quantification of SF OPG and RANKL levels was performed by ELISA, and the correlations of the results with clinical, laboratory and radiological parameters were assessed.
We found no statistically significant difference in the RANKL and OPG levels among the groups. Patients with RA showed a positive correlation between the SF cell count and RANKL level (r = 0.59; p < 0.05) and the RANKL/OPG ratio (r = 0.55; p < 0.05). Patients with OA showed a strong correlation between C-reactive protein (CRP) and the RANKL/OPG ratio (r = 0.82; p < 0.05). There was no correlation between the OPG and RANKL levels and markers of inflammatory activity or the disease activity index in patients with RA or SpA.
Within this patient cohort, the RANKL/OPG ratio was correlated with the SF cell count in patients with RA and with serum CRP in patients with OA, which may suggest a relationship with active inflammation and more destructive joint disease.
在慢性关节病中，有几种关节破坏机制。近年来的研究报告称，核因子 κB 受体激活剂配体（RANKL）和骨保护素（OPG）在破骨细胞的激活和分化过程中起作用，破骨细胞是骨侵蚀发展的关键细胞。恶性疾病和溶骨性骨病以及类风湿关节炎（RA）患者的血清中 RANKL/OPG 比值增加。本研究的目的是测量和比较类风湿关节炎（RA）、脊柱关节炎（SpA）和骨关节炎（OA）患者滑液（SF）中 OPG 和 RANKL 的浓度。
这是一项观察性和横断面研究，共纳入 83 例患者，其中 33 例为 RA，32 例为 SpA，18 例为 OA，这些患者均在里贝朗普雷图医学院-USP 临床医院的风湿病门诊定期随访。在 SF 采集时，主治医生根据每位患者的情况评估关节穿刺的适应证，并评估患者的人口统计学变量和药物使用情况。RA 和 SpA 患者评估疾病活动度。通过 ELISA 定量测定 SF OPG 和 RANKL 水平，并评估结果与临床、实验室和影像学参数的相关性。
我们发现三组之间的 RANKL 和 OPG 水平没有统计学差异。RA 患者 SF 细胞计数与 RANKL 水平（r=0.59；p<0.05）和 RANKL/OPG 比值（r=0.55；p<0.05）呈正相关。OA 患者 C 反应蛋白（CRP）与 RANKL/OPG 比值（r=0.82；p<0.05）之间呈强相关性。RA 和 SpA 患者的 OPG 和 RANKL 水平与炎症活动标志物或疾病活动指数无相关性。
在本患者队列中，RA 患者的 RANKL/OPG 比值与 SF 细胞计数相关，OA 患者的 RANKL/OPG 比值与血清 CRP 相关，这可能表明与活跃炎症和更具破坏性的关节疾病有关。
