Association of serum β-catenin and DKK1 with bone and joint damage in patients with rheumatoid arthritis / 中华风湿病学杂志

ABSTRACT

Objective To examine the plasma β-catenin and DKK1 levels in patients with rheumatoid arthritis (RA) and to explore their relationship with bone and joint damage in RA.Methods One hundred and thirteen patients with RA and 120 healthy individuals were recruited into this research.Bone mineral density (BMD) in the femur and lumbar spine were measured with dual-energy X-ray absorptiometry (DEXA).Radiographs for two hands were evaluated according to the Sharp's method.Serum levels of β-catenin and DKK1 in all patients with RA and healthy controls were detected by enzyme-linked immunosorbent assay (ELISA).The 2-tailed independent samples t test was used for measurement data.Chi-square test was used for the enumeration data.Correlation analysis,linear regression and Logistic regression analysis were used as appropriate statistical analysis.Results ① Significantly higher serum levels of DKK1 were observed in RA patients than that in healthy controls [(8±7) vs(6±4) μg/ml,t=2.552,P=0.012],while there was no sinnificant difference with regard to the levels of β-catenin between the two groups.② Compared to control groups,patients with RA had lower BMDs at femur and lumbar spine (P＜0.01).Furthermore,incidence of osteoporosis (OP) in RA (31.9％,36/113) was remarkablely higher than that in healthy subjects (15.0％,18/120) (x2=9.290,P=0.002).③ There were obvious discrepancies in age,swollen joint count (SJC),swollen joint count index (SJI),alkaline phosphatase (AKP),joint narrowing space score,joint erosion score,Sharp score between patients with osteoporosis and without osteoporosis (P＜0.05).④ In RA group,DKK1 level was posi-tively related with plasma erythrocyte sedimentation rates (ESR),28-jonit disease activity score (DAS28),AKP,joint narrowing space score (P＜0.05).Serum β-catenin level was associated with ESR,AKP in RA (P＜0.05).⑤ Multiple linear regression analysis indicated that in the RA group,disease duration (b=0.709,t=9.560,P＜0.01,95％CI2.154-3.286),HAQ (b=0.151,t=2.052,P=0.043,95％CI0.234-15.243),DKK1(b=0.286,t=2.057,P=0.043,95％CI0.034-2.028)were the contributors for joint space narrow score(R2=0.580,F=24.745,P＜0.01).⑥ Multiple Logistic regression analysis showed that the Sharp score (OR=1.018,P＜0.01,95％CI1.008-1.028) was the risk factor for the occurrence of osteoporosis at femur in RA,while age (OR=1.087,P=0.012,95％CI 1.019-1.159) was the risk factor for osteoporosis at lumbar spine.Conclusion Serum DKK1 levels in RA increase significantly,while there is no apparent alteration in plasma β-catenin.Serum DKK1 is correlated with disease activity and joint space narrow score.