Inhibition of GPVI or FXII suppresses collagen-dependent thrombus formation and platelet procoagulant activity. Blood from wild-type mice was flowed for 4 minutes over type I/H collagen under coagulant condition by coperfusion with CaCl2/MgCl2 buffer at a shear rate of 1000 s−1. Blood was pretreated with saline vehicle (control), CTI (4 μM), JAQ1 mAb (40 μg/mL), and FVIIai (100 nM), as indicated. No tissue factor was added. (A) Accumulation of PS-exposing platelets during perfusion (OG488-annexin A5 added to the blood). Representative experiment of 3 performed. (B) Projected confocal stacks (180 × 180 μm; height, 50 μm) of thrombi costained with AF546-fibrinogen and OG488-annexin A5. Bottom panels (side views) represent thrombus height. (C) Representative phase-contrast images (120 × 120 μm) of thrombi after perfusion. (D top panel) Surface area covered by all thrombi. (Bottom panel) Frequency distribution of small and large platelet thrombi (estimated number of platelets per feature indicated in box). Mean ± SEM; n = 4-5; *P < .05 vs vehicle control; #P < .05, χ2 test.
