The expression of oxidized low density lipoprotein and scavenger receptor that binds phospha-tidylserine and oxidized lipoprotein in patients with rheumatoid arthritis

Objective To investigate the expression level of oxidized low density lipoprotein (ox-LDL) and its scavenger receptor scavenger receptor that binds phosphatidylserine and oxidized lipoprotein (SR-PSOX) in patients with rheumatoid arthritis (RA), and to explore the relationship between ox-LDL and disease activity. Methods The serum ox-LDL in RA patients and healthy control group were detected by enzyme-linked immunosorbent assay (ELISA), as well as the fluidox-LDL in RA, osteoarthritis (OA) and inflammatory arthritis(IA). The expression of SR-PSOX in mixed cells of RA and IApatients was detected by western blot. The expression of serum ox-LDL between RA groupand the control group was analyzed by t-test and non-parametric test. The correlation of serum ox-LDL expression levels in RA patients with C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and other inflammatory factors and disease activitywas analyzed by Pearson linear regression. Results The expression of ox-LDL in the serum of RA patients was significantly higher than that of normal control group [(3 076±131) mU/ml, (2 334±84) mU/ml, t=4.242, P<0.01]. The expression of ox-LDL in synovial fluid of RA patients was significantly higher than that of the OA group[(4 963±354) mU/ml],(3 956±347) mU/ml, t=2.372, P<0.05). The expression of SR-PSOX in synovial fluid mixed cells of RA patients was higher than that of the IA group [(4.92±0.18) vs (0.24±0.04), t=33.53, P<0.01]. The expression of ox-LDL in serum of RA patients was negatively correlated with ESR, CRP and overall disease activity DAS28 (r=-0.42, P=0.009; r=-0.35, P=0.029 7; r=0.42, P=0.008 4). The expression of ox-LDL in the serum of RA patients with moderate disease activity was significantly higher than those patients with high disease activity [(3 302±138) mU/ml vs (2 464±228) mU/ml, t=3.335, P<0.01], however, those with low disease activity and disease remission had higher serum ox-LDL expression but without statistical significant differences. After treated with anti-rheumatic drugs (DMARDs), serum ox-LDL of RA patients had a trend of slight increasing butwithout sign-ificant difference. The ox-LDL/LDL-C or ox-LDL/HDL-C was negatively not correlated with disease activity score in 28 (DAS28), ESR, CRP. Conclusion In RA patients, the expression of ox-LDL in the serum and synovial fluid is high and the SR-PSOX expressionin synovial fluid is also high. The serum ox-LDL levels are negatively correlated with ESR, CRP and DAS28, which are related to disease activity of RA. These findings suggest that the ox-LDL and the receptor SR-PSOX may play a role in RA pathogenesis, but needs further study. Key words: Lipoproteins, low density lipoprotein; Arthritis, rheumatoid; Blood sedimentation; Oxidized low density lipoprotein; Scavenger receptor that binds phospha-tidylserine and oxidized lipoprotein