Dictionary > Factor VIII

Factor VIII

A blood coagulation factor that when activated by thrombin works with factor IX (Christmas factor) and calcium to activate factor X (Stuart factor)
Coagulation, the process of clot formation, involves platelet and blood clotting factors. In humans, the coagulation mechanism is comprised of two processes, i.e. the primary hemostasis and the secondary hemostasis. The latter entails two pathways: (1) intrinsic pathway (contact activation pathway) and (2) extrinsic pathway (tissue factor pathway). Both pathways lead to the formation of fibrin.
Factor VIII is involved in the intrinsic pathway of blood coagulation cascade. It is produced from the liver sinusoidal cells, the endothelial cells that line blood vessels, and the platelets (plug). When it circulates via the bloodstream it is in its inactive form. The inactive factor VIII is bound to von Willebrand factor. It is activated by thrombin. When activated, it works with factor IX (Christmas factor) and calcium to activate factor X (Stuart factor). It is a cofactor of factor IX, forming the TENASE complex.
In humans, it is coded by F8 gene. Defect in the gene may lead to deficiency of factor VIII, which in turn causes hemophilia A.

  • antih(a)emophilic factor (AHF)
  • antihemophilic globulin
  • antihemophilic globulin A
  • proserum prothrombin conversion accelerator
  • (blood) coagulation factor VIII
  • (blood) clotting factor VIII

See also:

  • clotting factor
  • coagulation
  • hemophilia

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