IL1R1 and atherosclerosis: Among all cell types involved in atherosclerosis, their investigation focused on vascular smooth muscle cells (VSMCs) for two reasons: 1) expansive remodeling involves the reorganization of the muscular layer of arteries, and 2) atheromata of Il1r1-/- mice contained fewer alpha-SMA+ cells than controls, indicating that the abrogation of IL-1 receptor signaling limited VSMC migration into the intima.