Diagnostic value of matrix metalloproteinases-1, −3 and −13 in patients with primary knee osteoarthritis: Relation to radiological severity

Knee osteoarthritis (KOA) is an important cause of disability in elderly. Aim of the work: to study the expression of matrix metalloproteinases (MMP-1, MMP-3 and MMP-13) in serum of patients with KOA and relation to radiological findings. One hundred patients with KOA and 80 matching control were studied. The Kellegren Lawrence (KL) scale was assessed. The mRNA and protein expressions of MMP-1, MMP-3 and MMP-13 were assessed by “quantitative real-time polymerase chain reaction (qRT-PCR)” and western blotting, respectively. There was a significant increase in the mRNA expression of MMP-1, MMP-3 and MMP-13 in patients (18.5 ± 3.4, 3 ± 0.5 and 2 ± 0.2, respectively) compared to controls (2.6 ± 0.4, 0.7 ± 0.3 and 0.3 ± 0.06, respectively)(all p < 0.001) and in the protein expression of MMP-1, MMP-3 and MMP-13 in patients (2.89 ± 0.01, 2.37 ± 0.07, 2.56 ± 0.02, respectively) relative to controls (1.15 ± 0.04, 0.79 ± 0.01, 1.02 ± 0.08 respectively (all p < 0.001). A significant correlation was found between the age of patients and mRNA expression of MMP-1 (r = 0.19, p = 0.01) and MMP-3 (r = 0.17, p = 0.019) and between the BMI and mRNA expression of MMP-1 (r = 0.16, p = 0.028). No significant correlation was found between mRNA expression of MMP-1, MMP-3 and MMP-13 and grade of KOA. At cut off values 5.5, 1.7 and 0.8, MMP-1, MMP-3 and MMP-13 could diagnose KOA at a sensitivity of 98 %, 100 % and 100 % respectively with 100 % specificity for all. The expression of MMP-1, MMP-3 and MMP-13 could be a valuable non-invasive marker for early diagnosis of primary KOA with no relation to radiological finding.