Department of Biochemistry, AIIMS, Bhubaneswar, Odisha, India.
Department of Orthopedics, AIIMS, Bhubaneswar, Odisha, India.
Indian J Med Res. 2021 Mar;154(3):491-496. doi: 10.4103/ijmr.IJMR_873_19.
BACKGROUND & OBJECTIVES: Osteoarthritis (OA) is the 11 leading cause of disability in the modern world, but till date, there have been no effective markers for monitoring the progression of OA. The three proteins RANK/RANK-Ligand and Osteoprotegerin (OPG) have been found to be the key regulators of bone metabolism. Interaction of RANK-Ligand with its receptor RANK triggers differentiation of osteoclasts leading to bone resorption. OPG on the other hand is protective as it is expressed by osteoblasts and bind RANKL with higher affinity preventing its interaction with RANK. The levels of these serum proteins are regulated by vitamin D and parathyroid hormones. Therefore, the present study, aimed to study the association of serum RANKL, OPG and vitamin D with disease severity in patients with knee OA.
It was a cross-sectional study where 80 (43 women and 37 men) newly diagnosed subjects with OA knee were recruited. They were classified into four grades based on K-L grading and into two groups as early (grade 1+grade 2) and advanced (grade 3 + grade 4) based on the disease progression.
On comparing the biochemical parameters among the four grades decreasing vitamin D levels were seen with increasing severity of knee OA; an increasing trend of RANKL with increase in the severity of OA was seen; OPG was found to be elevated more in the early stages of OA. We also observed a strong association of RANKL/OPG ratio with disease severity.
INTERPRETATION & CONCLUSIONS: Overall the results suggest that OPG may be considered as an early marker of the diseases.
骨关节炎（OA）是现代世界第 11 大致残原因，但迄今为止，还没有有效的标志物来监测 OA 的进展。三种蛋白 RANK/RANK 配体和骨保护素（OPG）已被发现是骨代谢的关键调节剂。RANK 配体与受体 RANK 的相互作用触发破骨细胞的分化，导致骨质吸收。另一方面，OPG 是保护性的，因为它由成骨细胞表达，并以更高的亲和力与 RANKL 结合，从而阻止其与 RANK 的相互作用。这些血清蛋白的水平受维生素 D 和甲状旁腺激素的调节。因此，本研究旨在研究血清 RANKL、OPG 和维生素 D 与膝骨关节炎患者疾病严重程度的相关性。
这是一项横断面研究，共招募了 80 名（43 名女性和 37 名男性）新诊断的膝骨关节炎患者。他们根据 K-L 分级分为四级，并根据疾病进展分为早期（1 级+2 级）和晚期（3 级+4 级）两组。
在比较四级之间的生化参数时，随着膝骨关节炎严重程度的增加，维生素 D 水平逐渐降低；随着 OA 严重程度的增加，RANKL 呈上升趋势；在 OA 的早期阶段，OPG 升高更为明显。我们还观察到 RANKL/OPG 比值与疾病严重程度之间存在很强的相关性。
总的来说，研究结果表明，OPG 可能被视为疾病的早期标志物。
