Tanaka Yoshiya
First Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health.
Nihon Rinsho. 2006 Dec;64(12):2359-66.
Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic synovitis and bone damages, which consist of joint destruction and systemic osteoporosis. During the pathological process, pro-inflammatory cytokines such as TNF-alpha are largely produced from inflamed synovium and cause activation of osteoclasts deviated from bone remodeling cycle, resulting in joint destruction. On the other side, systemic osteoporosis, mainly caused by glucocorticoid (GC) is often complicated in RA, in which GC decreases number of osteoblasts, reduces synthesis of bone matrix proteins from them and enhances bone resorption, resulting in impairment of bone remodeling. Thus, joint destruction and systemic osteoporosis are brought about by different mechanisms. However, recent treatment strategies have improved managements of RA-related joint destruction as well as GC-induced osteoporosis. Treatments using biologics including infliximab and etanercept, effective for treating RA disease activity, also reduce joint destruction. Also, bisphosphonate is well known to be effective for not only treatment but also prevention of GC-induced osteoporosis. Thus, it is a clinical trend that physicians treat joint destruction as an inflammatory disease and osteoporosis as a metabolic disease.
类风湿关节炎(RA)是一种全身性自身免疫性疾病,其特征为慢性滑膜炎和骨损伤,包括关节破坏和全身性骨质疏松。在病理过程中,促炎细胞因子如肿瘤坏死因子-α(TNF-α)主要由炎症滑膜产生,导致偏离骨重塑周期的破骨细胞活化,从而造成关节破坏。另一方面,主要由糖皮质激素(GC)引起的全身性骨质疏松在RA中常并发,其中GC减少成骨细胞数量,降低其骨基质蛋白合成并增强骨吸收,导致骨重塑受损。因此,关节破坏和全身性骨质疏松是由不同机制引起的。然而,最近的治疗策略改善了对RA相关关节破坏以及GC诱导的骨质疏松的管理。使用包括英夫利昔单抗和依那西普在内的生物制剂进行治疗,对治疗RA疾病活动有效,也可减少关节破坏。此外,众所周知,双膦酸盐不仅对治疗而且对预防GC诱导的骨质疏松均有效。因此,临床趋势是医生将关节破坏作为炎症性疾病治疗,而将骨质疏松作为代谢性疾病治疗。