AB0227 BASELINE SYNOVIAL LEVELS OF MATRIX METALLOPROTEINASES-9 IN EARLY RHEUMATOID ARTHRITIS-THE ASSOCIATION WITH INITIAL RADIOGRAPHIC CHANGES

Abstract

Background:Matrics metalloproteinases (MMPs) are the key enzymes responsible for the joint destruction in rheumatoid arthritis (RA).Objectives:The aim of this study was to examine the association of baseline levels of metalloproteinases-9 (MMP-9) in serum and synovial fluid (SF) with structural damage of hand and feet joints in patients with early RA and also with imunoserological markers of the disease.Methods:The study enrolled 134 subjects with knee synovitis: 72 patients with early DMARD-naïve RA (symptom duration ≤12 months) and 62 patients with osteoarthritis (OA), as control group. Synovial fluid was obtained by an arthrocentesis of the knee joint. Joint damage was estimated by hands, knee and feet radiography. With regard to the presence of destructive joint changes on initial x-ray, RA patients were classified as erosive and nonerosive form of disease. ELISA assay was used for the detection of MMP–9 activity in serum and SF as well for the imunoserology tests: rheumatoid factor RF (IgG) and anti-CCP antibody (ACPA).Results:MMP–9 activity in serum and SF of RA patients was significantly higher compared to its activity in serum and SF of control group (p<0.01 and p <0.001 respectly) (table 1).Table 1.MMP–9 activity (ng/ml) in serum and SF of RA and control group patientsGroupMMP-9 activity in BP(ng/ml); mean±SDMMP-9 activity in SF(ng/ml)mean±SDRA(n=72)18.28±7.54**15.07±13.24***Controls -OA(n=62)13.58±3.070.65±0.41RA – rheumatoid arthritis; SD – standard deviation; n – number of subjects; ** – p<0.01, *** p<0,001We did not establish a significant correlation between the activity of MMP 9 in serum and SF in the RA and control groups (Spearman’s rank correlation coefficient in RA was 0,02 and 0,06 in control group).Most of the subjects from RA group (52–72.22%) had verified radiographic erosive changes in joints. Nonerosive arthritis was present in remaning 20 (27.78%) of RA patients. No differences were obtained according to the sex, age or disease duration between erosive and nonerosive RA patients.Table 2 represents MMP–9 activity in serum and SF of patients with erosive and nonerosive RA. The values of MMP–9 activity measured in serum were higher in nonerosive compared to erosive RA (20.35±10.30 vs. 17.46±6.25), but the difference was not statistically significant (p>0.05). However, MMP–9 activity in SF was significantly higher in erosive compared to nonerosive RA (17.53±12.87 vs. 8.76±7.72; p<0.05).Table 2.MMP–9 activity (ng/ml) in serum and SF of patients with erosive and nonerosive RAMMP-9 activityErosive RA(n=52)[ng/ml]Nonerosive RA(n=20)[ng/ml]Serum17.46±6.2520.35±10.30Synovial fluid17.53±12.87*8.76±7.72RA – rheumatoid arthritis; SD – standard deviation; n – number of subjects; * p<0.05;We also examined the correlation of MMP 9 activity in serum and SF with standard imuno serological markers of disease (RF and ACPA). Our results indicate that there is a significant correlation of MMP 9 activity in SF with ACPA level in RA group (Spearman’s rank correlation coefficient is 0,48), but not with RF (Spearman’s rank correlation coefficient is 0.06).Conclusion:MMP–9 activity in serum and synovial fluid of patients with early RA is significantly higher compared to patients with osteoarthritis. High activity of MMP–9 in synovial fluid of patients with early RA correlated with ACPA level and may be a predictor of rapid radiographic progression of disease.