MMP9 and endothelial dysfunction: In addition, based on the hypothesis of a close relationship between extracellular matrix PGs/GAGs and the pathophysiology of accelerated atherosclerosis in RA, we also evaluated the effect of TNFαI on the vascular endothelial status by assessing the concentrations of selected biochemical markers of endothelial dysfunction such as sVCAM-1, MCP-1, MMP-9 and ADMA.