IL1B and aneurysm: In the small animal model used in this study, AngII-infused male apolipoprotein deficient mice develop suprarenal AAAs spontaneously without the need for surgical intervention.40 The formation of AAAs in this murine model and humane aneurysm formation have numerous commonalities, including medial elastic fiber degeneration, inflammatory processes and thrombus formation.41,42 AngII-infusion promotes macrophage infiltration, MMP activation as well as an increased release of cytokines, including IL-1β.43,44