Changes And Clinical Significances Of Serum Sclerostin Levels In Patients With Ankylosing Spondylitis And Rheumatoid Arthritis

Background and objectiveAnkylosing spondylitis (AS) is a chronic systemic auto-immune inflammatory disease, mainly involving young males. Bone formation occurs more often in inflammatory sites of AS patients, such as centrum, sacroiliac joint and ligament attachment point. The pathological characteristic lesion of AS is a chronic inflammation of joint synovium, and the fibrosis and ossification among joint surrounding tissue such as ligament, fibrousring, articular cartilage, articular capsule. Inflammatory bone destruction and repair bone augmentation are the basic reasons for deformity and ankylosis of joint. To control the development of AS and protect the function of joint and further prevent the disability of spinal stiffness, the most effective way is to stop inflammatory bone lesions.Rheumatoid arthritis (RA) is a chronic systemic autoimmune inflammatory disease, females are more likely to be affected.The pathological characteristic of RA includes synovial hyperplasia and inflammation, pannus formation, in the end bone erosion, cartilage loss and joint destruction. If left untreated, it would lead to joint damage and disability.Sclerostin is the product of osteocytes and can inhibit bone formation. The level of sclerostin of osteocytes is more lower in OA and AS patients than RA patients and normal controls,and it is lowest in AS patients.The serum sclerostin level in AS patients is lower than normal controls.Importantly,low serum sclerostin levels in patients with AS were closely associated with the formation of new syndesmophytes.Currently, most research has focused on the treatment of osteoporosis, we do not find the reasearch on the level of sclerostin in RA patients and explore the relationship between the serum level of sclerostin and erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), RA disease activity score (DAS28), Bath ankylosing spondylitis disease activity index (BASDAI). We test the serum sclerostin level in AS and RA patients, then explore the relationship between the changes of serum sclerostin level and other index and their clinical significance.MethodsSerum samples were obtained from 60 RA patients (30 Elderly RA,30 Young RA), 30 AS patients,60 normal control (NC) subjects (30 Young NC and 30 elder NC).Serum levels of sclerostin were detected by enzyme-linked immunosorbent assay so as to explore the difference between RA patients and AS patients and the correlation with systemic parameters of disease activity,such as ESR, CRP, DAS28, BASDAI.Results(1)The levels of sclerostin in AS group (16.87±11.79 pg/ml) was lower than young RA group(30.56±19.75pg/ml) and young normal control group(27.18±21.82 pg/ml) with significant difference(P<0.05);The levels of sclerostin in young RA group (30.56±19.75pg/ml) were higher than young normal controls group (27.18±21.82 pg/ml) but without significant difference (P>0.05). The same case happened in elder RA group (30.66±21.54pg/ml) vs elder normal control group (30.28±13.71 pg/ml) as well as elder normal control group (30.28±13.71 pg/ml) vs young normal controls group (27.18±21.82 pg/ml). (2)Correlations between serum sclerostin levels and CRP, ESR, DAS28 scores,age were detected in the young RA patients (P>0.05); Correlations between serum sclerostin levels and CRP, DAS28 scores,age were detected in the elder RA patients (P>0.05),but not with ESR(r=-0.414, P<0.05). Correlations between serum sclerostin levels and CRP, ESR, BASDAI,age were detected in AS patients (P>0.05).Conclusion1. Serum levels of sclerostin were lower in patients with AS than in normal controls, Serum levels of sclerostin tended to be higher in RA groups than in noamal groups, but without significant difference.2. sclerostin could not serve as a indicator in a systemic inflammatory condition to assess activities of AS and RA patients.3. the level of serum sclerostin was affected by age.