The role of factor V Leiden (FVL) as a modifier of the severe hemophilia phenotype is still
unclear. We used mice with hemophilia A or B crossed with FVL to elucidate in vivo
parameters of hemostasis. Real-time thrombus formation in the microcirculation was
monitored by deposition of labeled platelets upon laser-induced endothelial injury using
widefield microscopy in living animals. No thrombi formed in hemophilic A or B mice
following vascular injuries. However, hemophilic mice, either heterozygous or homozygous …