The relationship between dynamic knee joint load and matrix metalloproteinases in people with and without knee osteoarthritis

Introduction: Knee osteoarthritis (OA) is a destructive joint disease resulting from a number of factors including excessive and repetitive loading of the joints. Even though OA symptoms begin mostly in midlife, the degenerative changes of articular cartilage take place a long time before the onset, so it is important to track osteoarthritic changes at earlier phases. Radiology imaging is widely used for this purpose; however, radiology does not show minute changes that occur before onset of OA symptoms. Due to such limitations, the investigation of molecular changes is growing in today’s research. Matrix metalloproteinases (MMPs) are degenerative enzymes of connective tissue and their quantities are thought to be related to OA changes. Our goal was to investigate how MMP variance is explained by OA–related factors, mainly dynamic knee joint loading. Methods: A cross-sectional design was used to collect data on the intraarticular knee joint load, reflected by knee adduction moment (KAM), as well as serum samples in 28 participants of which half had mild to severe OA and the other half were OA-free. Laboratory-based motion analysis was used to compute the KAM, while MMP levels (MMPs- 1, 3, 13) were measured using ELISA. Multiple-regression analysis was used to investigate the explanatory role of KAM, and potential confounders like age, and OA severity in explaining MMP variance. Results: KAM impulse predicted significant variance in MMP-3 levels (R²=0.197, p=0.018). After controlling for the effect of age and severity, the explanatory role of KAM impulse was decreased (R²=0.157), still remaining statistically significant (p=0.036). The explained variance of MMP-1, 13 did not reveal statistical significance from explanatory variables. Conclusion: This research provides evidence of a positive relationship between MMP- 3 and intraarticular knee joint load, quantified by the KAM. The relationship remained significant after controlling for age and OA severity. Our findings support the notion that MMP-3 may be a candidate for OA investigations. Since MMP levels are influenced by a number of factors, it seems logical to consider the levels of other biomarkers along with them.Medicine, Faculty ofGraduat