Related Experiment Video
Updated: May 30, 2026

Tail Vein Transection Bleeding Model in Fully Anesthetized Hemophilia A Mice
Published on: September 30, 2021
Procoagulant activity induced by vascular injury determines contribution of elevated factor VIII to thrombosis and
Kellie R Machlus1, Feng-Chang Lin, Alisa S Wolberg
1Department of Pathology and Laboratory Medicine, North Carolina Translational and Clinical Sciences Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Abstract:
Studies have correlated elevated plasma factor VIII (FVIII) with thrombosis; however, it is unclear whether elevated FVIII is a proinflammatory biomarker, causative agent, or both. We raised FVIII levels in mice and measured the time to vessel occlusion (TTO) after ferric chloride-induced injury. Compared with control (saline-infused) mice, elevated FVIII had no effect after longer (3-minute) carotid artery injury, but it shortened the TTO after shorter (2-minute) injury (P < .008). After injury, circulating thrombin-antithrombin (TAT) complexes were lower after short versus long injury (P < .04), suggesting short treatment produced less coagulation activation. TAT levels in FVIII-infused mice were higher than in controls after short, but not longer, injury. Accordingly, elevated FVIII had no effect on in vitro thrombin generation or platelet aggregation triggered by high tissue factor, but it increased thrombin generation rate and peak (2.4- and 1.5-fold, respectively), and it accelerated platelet aggregation (up to 1.6-fold) when initiated by low tissue factor. Compared with control mice, elevated FVIII stabilized thrombi (fewer emboli) after short injury, but it had no effect after longer injury. TTO and emboli correlated with TATs. These results demonstrate dependence of FVIII activity on extent of vascular injury. We propose elevated plasma FVIII is an etiologic, prothrombotic agent after moderate but not extensive vascular damage.
Related Concept Videos
Anticoagulant Drugs: Low-Molecular-Weight Heparins
Extrinsic and Intrinsic Pathways of Hemostasis
The Extrinsic Pathway
The extrinsic pathway of coagulation is typically initiated by tissue damage that exposes blood to tissue factor (TF), a protein released by the damaged tissue cells outside the blood vessels—this interaction with TF triggers biochemical reactions involving specific clotting factors. The key player here is Factor VII, which forms a...
Clot Retraction and Fibrinolysis
Coagulation
During the coagulation phase, clotting factors, or procoagulants, play a vital role in initiating and progressing the coagulation cascade. This cascade is a series of reactions...
Venous Thrombosis III: Interprofessional Care
Formation of the Platelet Plug
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...

