MMP2 and triple-A syndrome: As such, doxycycline has been used in a number of preclinical and clinical studies to modulate MMP activity: doxycycline therapy reduces MMP-2 and -9 expression and vessel wall inflammation in human abdominal aortic aneurysm (AAA)32, 34, 35, global and MMP-2/9 activity in left ventricular remodeling after myocardial infarction21, 22, and MMP-1 expression in carotid atherosclerotic plaque27.