MMP9 and atherosclerosis: MMP14 was also related to the activity regulation of other MMPs, such as MMP2 and MMP13.34, 35, 36, 37 Deficiency of MMP2, MMP8, or MMP9 led to smaller atherosclerotic lesions with fewer smooth muscle cells and reduced macrophage infiltration.38, 39, 40, 41, 42 The roles of MMP12 in atherosclerosis are controversial and studies on MMP10 and MMP11 are still limited.