ELMO1 regulates thrombus formation in vitro. Representative light microscopic image of thrombus formation on a collagen-coated surface (A) and percent thrombus area (B). Whole blood from WT littermate controls and ELMO1^−/− mice was perfused over a collagen (50 μg/mL)–coated surface at arterial shear rate 1000 s⁻¹ or venous shear rate 200 s⁻¹ for 4 minutes. The direction of flow was right to left. (B) Images were analyzed using ImageJ, and data are presented as percent thrombus area ± SE. Data were analyzed by Student t test (*P < .05). WT and ELMO1^−/−, n = 3.