Murine 1399H VWF demonstrates defect in shear-induced collagen 4 binding. VWF-deficient mice were injected with either WT or p.1399H murine VWF DNA to achieve temporary correction of their VWF levels. Blood samples were obtained 24 hours postinjection. Binding to collagen 4 under flow conditions was assessed using the Venaflux system at 37°C using a shear rate of 1111 s−1. Platelets were labeled with mepacrine for visualization. (A) Platelet adhesion after 180 seconds for a representative sample from a mouse injected with WT VWF (panel 1) and a mouse injected with 1399H VWF (panel 2). Images were obtained using a Zeiss Axio Observer.A1 microscope at ×10 original magnification and a Hamamatsu Orca R2 camera. (B) VWF:Ag levels obtained 24 hours postinjection for WT (n = 4) and 1399H (n = 4) mice. (C) VWF:CB4 levels obtained 24 hours postinjection for WT (n = 4) and 1399H (n = 4) mice. (D) Platelet adhesion as measured by number of platelet aggregates for 1399H-injected mice (n = 3) compared with WT-injected mice (n = 4).
