Levels of metalloproteinase (MMP-3, MMP-9), NF-kappaB ligand (RANKL), and nitric oxide (NO) in peripheral blood of osteoarthritis (OA) patients.

BACKGROUND: The aim of this study was to judge whether there is a correlation between some biochemical features of knee osteoarthritic blood and clinical characteristics and to evaluate the potential relationship between osteoarthitis (OA) severity and putative biomarkers for the disease.

METHODS: 105 patients suffering from knee OA were analyzed clinically (Lequesne's index) and radiographically (Kellgren and Lawrence, K&L). Plasma and peripheral blood mononuclear cells (PBMC) were harvested separately. Specimens were analyzed for concentrations of nitric oxide (NO), matrix metalloproteinase-3 (MMP-3), and matrix metalloproteinase-9 (MMP-9). Transcript levels of the receptor activator of NF-kB ligand (RANKL) mRNA, MMP-3mRNA, and MMP-9mRNA were measured using real-time quantitative RT-PCR.

RESULTS: Data certified significantly increasing concentrations of plasma MMP-3, MMP-9, and NO as well as transcript levels of RANKL mRNA and MMP-9 mRNA in early OA (at grade I). There was a positive correlation of MMP-3 and MMP-9 content in plasma and MMP-9 mRNA expression levels in PBMC with the severity of clinical symptoms (total Lequesne's scores) in early OA. NO content in plasma correlated with total Lequesne's scores, pain scores in response to pressure, and swelling scores of early OA patients (atgGrade I). Analogously, there were positive correlations of RANKL mRNA expression with total Lequesne's scores, pain scores in response to pressure, and swelling scores in OA patients at Grade I.

CONCLUSIONS: [corrected] Some biochemical factors, including content of NO, MMP-3, MMP-9, and transcript levels of some genes, including MMP-9 mRNA and RANKL mRNA, may be specific and sensitive enough to diagnose OA diseases at an early stage in the pathological process of OA when radiological features do not reflect degradation of articular cartilage. Therefore, proper regulation of these factors may be a promising and realistic new target for the treatment of degenerative osteoarticular diseases.