APOE and aortic aneurysm: Next, we investigated the feasibility of MMP-12-targeted imaging in a model of carotid artery aneurysm in high fat-fed apoE−/− mice, where adventitial application of CaCl2 to carotid artery leads to significant MMP-12 upregulation, inflammation, and carotid artery dilatation (Fig. 6A) after 4 weeks18.