By using the calibrated automated thrombin generation assay, we showed that a PN-1-neutralizing antibody could significantly shorten the thrombin burst in response to tissue factor in platelet-rich plasma (PRP) from patients with mild or moderate hemophilia.
Citrated whole blood and plasmas obtained from haemophilia participants were supplemented ex vivo with vehicle, marstacimab, recombinant FVIII (rFVIII) or recombinant factor IX (rFIX) and analysed in ROTEM, TGA and the dPT assay using low tissue factor concentrations to trigger coagulation.
In several other studies different aspects of platelet function in hemophilia have been investigated in more detail and various alterations were discovered, such as increased platelet P-selectin expression, a lower number of procoagulant, so-called 'coated' platelets, lower aggregation upon co-incubation with tissue factor, or reduced platelet contractile forces during clot formation in comparison to healthy individuals.
Mice expressing low levels of human TF (LTF mice), mice expressing relatively high levels of human TF (HTF mice) and wild-type mice (WT mice) had neutralizing anti-FVIII antibodies administered in order to induce hemophilia in these mice.
Both the activated partial thromboplastin time assay and the whole blood thromboelastographic analysis confirmed that AAV-FVIII vectors fully corrected the bleeding phenotype of hemophilia mice.