MMP9 and abdominal aortic aneurysm: Glutamine protected against mouse abdominal aortic aneurysm through inhibiting M1 macrophage activation, secretion of IL-6 and TNF-α by macrophage, release of MMP-9 by RAW264.7 (macrophage) and MMP-2 by MOVAS (SMC), as well as apoptosis of vascular SMC by ROS and MMP (Figure 7).