MMP9 and Hypertension: Although activation of vascular MMP2 and MMP9 in hypertension is associated with collagen accumulation, activation of MMP8 and MMP13 is associated with collagen degradation, processes especially important in arterial wall plaque and plaque rupture.22, 23 MMP2/MMP9 activation through TGF-β1/SMAD signalling also induces activation of myofibroblasts and increased infiltration of monocytes/macrophages, leading to oxidative stress, inflammation, and vascular wall injury.