VWF/p.V1316M decreases hemostasis in a laser-injury model. Quantitative analysis (SlideBook software) of platelet accumulation and bleeding time after laser injury to the saphenous vein of WT-VWF/WT (red) and WT-VWF/p.V1316M (blue) mice. Mice were injected with an Alexa Fluor 488–labeled antibody against GPIX to monitor platelet accumulation. Repeated vascular injury was induced by laser ablation. (A) Representative images at the indicated times after the first injury. Intravital microscopy was performed with a Zeiss Examiner Z1 microscope (Zeiss, Oberkochen, Germany) equipped with a Hamamatsu Orca Flash 4.0 camera (Hamamatsu Photonics, Hamamtsu City, Japan) and a 20× water immersion objective (numerical aperture 1, working distance 1.8 mm) (Zeiss, Jena, Germany). Scale bars, 50 μm. (B) Accumulation of platelets at the site of injury, quantified as sum fluorescence intensity (± SEM). (C) Bleeding time. (D) Bleeding time after the first laser injury to the saphenous vein of WT-VWF/WT mice (red bar), control mice with low peripheral platelet counts (low-PLT; light green bar), and WT-VWF/p.V1316M mice (blue bar). Low-PLT mice were generated by adoptive transfer of WT platelets into thrombocytopenic IL4R-IbαTg mice, yielding a PPC ∼0.7 × 10⁸/mL of blood. Data for WT-VWF/WT and WT-VWF/p.V1316M mice are the same as in (C). Total number of injuries at distinct locations: n = 30 (obtained in 3 WT-VWF/WT mice), n = 38 (obtained in 5 WT-VWF/p.V1316M mice), and n = 15 (obtained in 4 low-PLT mice). Data in panels C-D are mean ± SD. **P ≤ .01; ***P ≤ .001.