Factor VII
From Wikipedia, the free encyclopedia
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coagulation factor VII
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| Identifiers | |
| Symbol | F7 |
| HUGO | 3544 |
| Entrez | 2155 |
| OMIM | 227500 |
| RefSeq | NM_000131 |
| UniProt | P08709 |
| Other data | |
| Locus | Chr. 13 q34 |
Factor VII (formerly known as proconvertin) is one of the central proteins in the coagulation cascade. It is an enzyme (EC 3.4.21.21) of the serine protease class.
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[edit] Physiology
The main role of factor VII (FVII) is to initiate the process of coagulation in conjunction with tissue factor (TF). Tissue factor is found on the outside of blood vessels - normally not exposed to the bloodstream. Upon vessel injury, tissue factor is exposed to the blood and circulating factor VII. Once bound to TF, FVII is activated to FVIIa by different proteases, among which are thrombin (factor IIa), activated factor X and the FVIIa-TF complex itself. The most important substrates for FVIIa-TF are Factor X and Factor IX.
The action of the factor is impeded by tissue factor pathway inhibitor (TFPI), which is released almost immediately after initiation of coagulation. Factor VII is vitamin K dependent; it is produced in the liver. Use of warfarin or similar anticoagulants impairs its function.
[edit] Genetics
The gene for factor VII is located on chromosome 13 (13q34).
[edit] Role in disease
Deficiency is rare (congenital proconvertin deficiency) and inherits recessively.
[edit] Therapeutic use
Recombinant human factor VIIa (NovoSeven®, eptacog alfa [activated], ATC code B02BD08) has been introduced for use in uncontrollable bleeding in hemophilia patients who have developed inhibitors against replacement coagulation factor.
It is being increasingly used in uncontrollable hemorrhage (Roberts et al 2004). The rationale for its use in hemorrhage is, that it will only induce coagulation in those sites where tissue factor (TF) is also present. Still, O'Connell et al (2006) report an increased risk of deep vein thrombosis, pulmonary embolism and myocardial infarction in association with the use of rhFVIIa. Other researchers have focused on the risk of acute intracerebral hemorrhage.[1]
Although the federal government has not approved Recombinant Factor VII, medics in Iraq are using it to treat critically wounded American soldiers. It is mostly when the soldiers are transferred to Germany or Iraq that they develop seemingly unexplainable clots.[2]
[edit] References
- O'Connell KA, Wood JJ, Wise RP, Lozier JN, Braun MM. Thromboembolic adverse events after use of recombinant human coagulation factor VIIa. JAMA 2006;295:293-298. PMID 16418464.
- Roberts HR, Monroe DM, White GC. The use of recombinant factor VIIa in the treatment of bleeding disorders. Blood 2004;104:3858-64. PMID 15328151.
- ^ Stephan A. Mayer, M.D., Nikolai C. Brun, M.D., Ph.D., Kamilla Begtrup, M.Sc., Joseph Broderick, M.D., Stephen Davis, M.D., Michael N. Diringer, M.D., Brett E. Skolnick, Ph.D., Thorsten Steiner, M.D., "Recombinant Activated Factor VII for Acute Intracerebral Hemorrhage" New England J of Med" Volume 352:777 - 785 February 24, 2005 Number 8
- ^ "Bleeding in the Baghdad ER" Baltimore Sun November 21, 2006
