Coagulation factors

1. COAGULATION FACTORS OMKAR PATNAIK
21064
BATCH 2021, AIIMS HYD

2. WHAT IS
COAGULATION ?
Coagulation is a process of
aggregation or accumulation of
colloidal particles to settle
down as a precipitate.
In human body, is the process
by which blood changes from a
liquid to a gel, forming a blood
clot.

3. HEMOSTASIS
Thrombohaemmorhagic balance is maintained in the body by complicated interactions between
coagulation and the fibrinolytic system as well as platelets and vessel wall.

4. Majority of clotting factors are precursors of
proteolytic enzymes known as zymogens
that circulate in an inactive form.
Most of the procoagulants and
anticoagulants are produced by liver except
factor III, IV and VIII.
These proteins undergo a post translational
modification (vitamin K dependent ϒ
carboxylation of glutamic acid residues)
which enables them to bind calcium and
other divalent cations and participate in
clotting cascade.

5. FACTOR VIII : ANTI HAEMOPHILIA FACTOR
A
1. The gene for factor VIII is located on the X
chromosome at q28. It is synthesized in liver.
Its half-life is 8 to 12 h when it is associated with vWF.
The half-life is reduced when concentration of vWF is
reduced in plasma. Therefore, deficiency of vWF also
reduces the level of VIII.
Factor VIII is activated by thrombin or Xa and the
activation results in its release from vWF.
The main function of VIIIa is to activate X to Xa.
Deficiency: Hemophilia A

6. FACTOR IX : ANTI HAEMOPHILIA FACTOR B
CHRISTMAS FACTOR
It is synthesized in liver dependent on vitamin K.
It has the half-life of 18–24 h.
The gene for factor IX is located on the tip of long arm of X
chromosome. Therefore, hemophilia B is a sex- linked disorder.
Factor IX is activated by XIa or VIIa-TF complex.
Along with cofactor VIIIa, it activates factor X. This activity is
physiologically expressed on the surface of platelets and
evidences suggest that platelets have receptors for IXa.
Deficiency: Hemophilia B/ Christmas disease

7. FACTOR X : STUART PROWER FACTOR
1. It is a vitamin K-dependent polypeptide synthesized by liver.
2. It has molecular weight of 59,000 and plasma half-life of 34 to 40
hours.
3. The gene for factor X is located on the chromosome 13 in close
proximity to factor VII gene.
4. Activation of Factor X is the target of both intrinsic and extrinsic
pathways of coagulation.
5. It is activated by IXa of intrinsic pathway and VIIa of extrinsic
pathway.
6. The primary function of factor Xa is the conversion of prothrombin
to thrombin. It has also mitogenic activity for smooth muscle cells. It
possesses receptor mediated pro-inflammatory activity.
Factor X Deficiency Emerging now.

8. FACTOR XI : ANTI HAEMOPHILIA FACTOR C
TISSUE THROMBOPLASTIN ANTECEDENT
1. Factor XI is synthesized in liver.
2. The gene for factor XI is located on
chromosome 4 at q32–35.
3. Factor XI is activated by factor XIIa, the
process which is accelerated by HMW kininogen.
4. The major function of factor XIa is to convert IX
to IXa.
5. It is inhibited by plasma protease inhibitors,
such as α1-trypsin inhibitor, C1-esterase inhibitor,
α2-plasmin inhibitor and AT-III.
Deficiency: Parahemophilia

9. FACTOR XII : HAGEMAN FACTOR
1. This is also called glass factor or
contact factor.
2. The gene for factor XII was located
on chromosome 5.
3. Factor XII is activated when it comes
in contact with negatively charged
surface. This is called contact
activation. HMW kininogen and
prekallikrein facilitate the process.
4. XIIa promotes the conversion XI to
XIa.
Deficiency is genetically inherited.

10. FACTOR XIII : FIBRIN STABILISING FACTOR
1. In addition to its presence in plasma, it is also found
in platelets, monocytes and macrophages.
2. The plasma XIII contains both A and B chains, and
the cellular XIII contains only A chain.
3. The gene for A chain is located on chromosome 6
and the gene for B chain is located on chromosome 1.
4. Thrombin causes cleavage of A and B subunits of XIII
that causes exposure of active site on A chain. This
activates XIII to XIIIa. The XIIIa cross-links α and β
chains of fibrin to stabilize the fibrin plug. In XIIIa
deficiency, though clot formation occurs, hemostasis
becomes inadequate.
5. It also promotes wound healing and tissue repair. It
helps in maintenance of pregnancy.
Deficiency: causes prolonged umbilical cord
bleeding

12. DRUGS AFFECTING COAGULATION
FACTORS
Recombinant factors
Direct factor Xa inhibitors- Rivaroxaban,
Apixaban
Heparin, LMWH complexes with AT-III and
binds to different clotting factors- Xa, IXa,
IIa, XIIa, XIIIa)

13. REFERENCES
Robbins basic pathology / [edited by] Vinay Kumar, Abul K. Abbas, Jon C. Aster. – 9th ed.
Essentials of Medical Pharmacology Eighth Edition KD TRIPATHI
Palta S, Saroa R, Palta A. Overview of the coagulation system. Indian J Anaesth. 2014
Sep;58(5):515-23. doi: 10.4103/0019-5049.144643. PMID: 25535411; PMCID: PMC4260295.
https://onlinelibrary.wiley.com/doi/full/10.1046/j.1365-2141.1999.01689.x
Comprehensive Textbook of Medical Physiology, G.K. PAL

14. THANK YOU