Related Experiment Video
Updated: Jul 8, 2025
08:13
Tail Vein Transection Bleeding Model in Fully Anesthetized Hemophilia A Mice
Published on: September 30, 2021
6.2K
Extravascular factor IX pool fed by prophylaxis is a true hemostatic barrier against bleeding
Alexandre Leuci1, Nathalie Enjolras1, Muriel Marano1
1UR4609 Hémostase et Thrombose, Université Claude Bernard Lyon 1, Lyon, France.
Journal of Thrombosis and Haemostasis : JTH
|December 10, 2023
Summary
Extravascular Factor IX (FIX) accumulates with prophylaxis, enhancing coagulation and bleeding protection in hemophilia B. This suggests a significant role for extravascular FIX in managing bleeding disorders.
Area of Science:
- Biochemistry
- Hematology
- Pharmacology
Background:
- Factor IX (FIX) binds to type IV collagen in the endothelial basement membrane, facilitating extravascular diffusion.
- Rodent studies indicate substantial biodistribution of FIX.
- Understanding extravascular FIX is crucial for hemophilia B treatment.
Purpose of the Study:
- To assess the hemostatic potential of extravascular FIX.
- To investigate the role of extravascular FIX in preventing joint bleeds.
Main Methods:
- Evaluated the binding capacity of four FIX molecules (plasma-derived and recombinant) to type I and type IV collagen.
- Administered FIX molecules intravenously to FIX knockout mice at doses ranging from 50 to 3000 IU/kg.
Main Results:
- Immunohistochemistry detected FIX in liver, muscles, and knee joints with recombinant FIX at 1000 and 3000 IU/kg, but not at lower clinical doses.
- Plasma-derived FIX showed a signal at all doses, including 50 IU/kg.
- Five daily infusions of recombinant FIX (100 IU/kg) led to extravascular accumulation and significantly higher procoagulant activity in bleeding assays compared to a single infusion.
Conclusions:
- Regular prophylaxis with FIX leads to extravascular accumulation.
- This accumulation significantly impacts coagulation capacity.
- Extravascular FIX plays a key role in bleeding protection for severe hemophilia B patients.
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