Research Of Bone Metabolism And Influencing Factors In Patients With Rheumatoid Arthritis

ObjectiveChronic inflammation can contribute to bone loss,resulting in abnormal bone metabolism,imbalance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption,and consequently leading to osteoporosis(OP)and pathological fractures.However,the mechanisms regarding this phenomenon are still unknown.Bone turnover markers(BTM)are defined as factors participating in the process of bone synthesis or catabolism,which include various hormones,immune cells and cytokines,osteoblasts and osteoclasts produce fragment of proteins and derivatives,etc.Patients with rheumatoid arthritis(RA)are often associated with abnormal bone metabolism during the progress of the disease.In recent years,research on RA bone metabolism has attracted more and more attention.The aim of this study was to investigate potential factors for bone metabolism in RA patients,and provide evidence for detecting RA bone destruction at early stage,guiding treatment regime and evaluating curative effects.Methods1.Dual-energy X-ray absorptiometry and chemiluminescence immunoassay were used to detect bone mineral density(BMD)and two specific BTM of 60 RA individuals and 32 healthy controls.The levels of N_terminal propeptide of type ? procoliagen(PINP)and beta C-terminal cross-linked telopeptides of type 1 collagen(p-CTX)were compared between RA group and control group.The bone metabolism of RA was evaluated by comparing the differences of BMD and BTM in RA individuals and healthy controls.2.Incidence of OP in RA group and control group were compared.More specifically,OP incidence in different age,gender and menopausal were analyzed in RA group.3.Correlation between BTM and age,disease duration,BMD,C-reactive protein(CRP),Erythrocyte sedimentation rate(ESR),Disease activity score in 28 joints(DAS28 score),Rheumatoid factor(RF),Anti-cyclic citrullinated peptide antibody(anti-CCP antibodies),Thl/TH2/TH17 cytokines and other laboratory indicators were analyzed in 60 RA patients.Furthermore,factors which may affect the BTM changes,were also compared in RA patients4.The levels of PINP and P-CTX were measured in 24 RA individuals at baseline and after 3 months of Yunke([99Tc]methylene diphosphonate)treatment,and the changes before and after treatment were compared to evaluate the effectiveness of Yunke treatment in improving bone resorption.Results1.Compared with healthy control,the concentrations of PINP and ?-CTX in RA individuals were significantly higher.Conversely,the L1-4 lumbar spine and femoral neck T score in RA group were significantly lower than those in control group.2.The OP incidence in the RA group was significantly higher,compared with the control.Similarly,the OP incidence in female was significantly higher than that in male.The incidence of OP in postmenopausal female was significantly higher than that in non-menopausal female.The incidence of OP in the elderly is significantly higher than that in the non-elderly.3.The rectilinear correlation analysis showed that ?-CTX in RA group was positively correlated with IL-6 and ESR,but negatively correlated with IL-4 and TNF.However,there was no significant correlation between ?-CTX and age,disease duration,CRP,RF,anti-CCP antibody,DAS28-ESR or IL-17.Moreover,PINP was positively correlated with IL-6 and ESR in RA group,but the correlations with age,disease duration,CRP,RF,anti-CCP antibody,DAS28-ESR,TNF,IL-4 or IL-17,were not statistically significant.And multiple linear regression analysis showed that the ?-CTX was negatively correlated with IL-4 and TNF,PINP was positively correlated with ESR.4.The ?-CTX levels of 24 patients with RA after 3 months of Yunke treatment was significantly lower than that at baseline,indicating a statistically significant difference;the PINP level was higher than that before treatment,and the difference was not statistically significant.Conclusion:1.RA individuals are predisposed to high conversion osteoporosis,obviously abnormal bone metabolism and common bone loss.2.RA individuals have higher incidence of OP than healthy controls.Moreover,OP incidence for female,the elderly,and postmenopausal status is greater than that for male,non-elderly,and non-menopausal,respectively.3.Factors which affecting bone resorption in RA individuals are revealed to include TNF,IL-4,that affecting bone formation is ESR.Furthermore,bone metabolic activity is associated with inflammation and disease activity.4.Yunke plays a significant role in improving bone resorption as treatment for RA,and using BTM to evaluate the therapeutic effect is clinically certain.