Blood is a Liquid connective tissue that consists of cells (platelets, RBCs, WBCs) surrounded by the liquid extracellular matrix (plasma). Platelets, or thrombocytes, are small, colorless cell fragments in our blood that form clots and stop or prevent bleeding. Platelet receptors either activate platelets or they act as adhesion molecules which interact with the damaged endothelium, other platelets and leukocytes Hemostasis (Haemostasis) is a process to prevent and stop bleeding. Anti coagulant drugs used to reduce coagulability of blood Thrombosis is prevented by several regulatory mechanisms that require healthy vascular endothelium

1. COAGULANTS,
ANTICOAGULANTS AND
FIBRINOLYTICS
Prepared by-
Deepanjali Sharma
M.Pharm (Pharmacology)
Semester 1

2. General Physiology
2

3. History
◦ Johannes Müller (1801–1858) described fibrin, the substance of
a thrombus. Its soluble precursor, fibrinogen, was thus named by Rudolf
Virchow (1821–1902), and isolated chemically by Prosper Sylvain
Denis (1799–1863).
◦ Platelets were identified in 1865, and their function was elucidated
by Giulio Bizzozero in 1882.
◦ Arthus discovered in 1890 that calcium was essential in coagulation.
◦ The view that the coagulation process is a "cascade" or "waterfall" was
enunciated almost simultaneously by MacFarlane in the UK and by Davie
and Ratnoff in the USA, respectively.
3

4. ◦ Hageman factor, now known as factor XII, was identified in 1955 in
an asymptomatic patient with a prolonged bleeding time named of
John Hageman. Factor X, or Stuart-Prower factor, followed, in 1956.
◦ Factor IX was discovered in 1952 in a young patient with hemophilia
B named Stephen Christmas (1947–1993).
◦ His deficiency was described by Dr. Rosemary Biggs and
Professor R.G. MacFarlane in Oxford, UK. The factor is, hence,
called Christmas Factor.

5. Blood
◦ Liquid connective tissue that consists of cells (platelets, RBCs, WBCs)
surrounded by the liquid extracellular matrix (plasma).
◦ pH=7.35 to 7.45
◦ Major types of blood cells include red blood cells (erythrocytes), white
blood cells (leukocytes), and platelets (thrombocytes).
◦ Together, these three kinds of blood cells add up to a total 45% of the
blood tissue by volume, with the remaining 55% of the volume
of plasma, the liquid component of blood.
5

6. 6

7. Platelets
◦ Platelets, or thrombocytes, are small, colorless cell
fragments in our blood that form clots and stop or
prevent bleeding.
◦ Thrombopoiesis is the formation of platelets in the Bone
marrow.
◦ A megakaryocyte is a large bone marrow cell with
a lobated nucleus responsible for the production of
blood thrombocytes
◦ Megakaryocytes produce Proplatelets within their
cytoplasm which then break up into hundreds of platelets
that circulate into the bloodstream.
◦ β1-tubulin microtubules, which are found in
megakaryocytes, facilitate this process of shedding
platelets into the bloodstream.
7

8. Platelets
◦ Megakaryocytes give rise to 1,000 to
3,000 platelets.
◦ Megakaryocyte development is
regulated mainly by thrombopoietin.
◦ A normal platelet count is 150,000 to
450,000 platelets per microliter of blood.
8

9. THROMBIN
◦ Thrombin an enzyme in blood plasma which causes the clotting
of blood by converting fibrinogen to fibrin.
◦ Thrombin is an unique molecule that functions both as
a procoagulant and anticoagulant. In its procoagulant role it
activates platelets through its receptor on the platelets. It
regulates its own generation by activating coagulation factors V,
VIII and even XI resulting in a burst of thrombin formation.
9

10. Platelet receptors
◦ Platelet receptors either activate platelets or they act as adhesion molecules
which interact with the damaged endothelium, other platelets and leukocytes
◦ Some of the well-recognized platelet receptors are;
◦ Integrins,
◦ Leucine-rich repeats receptors,
◦ Selectins,
◦ Transmembrane receptors,
◦ Prostaglandin receptors,
◦ lipid receptors,
◦ Tyrosine kinase receptors
◦ Serotonin receptors.
10

11. Integrins
◦ Integrins are adhesion and signaling molecules
◦ These are non-covalently bound heterodimers of α and β subunits. Platelets have
three types of integrins i.e. β1, β2 and β3.
β1 family
◦ It has three members i.e. α2β1, α5β1 and α6β1.
◦ α2β1 receptor or GPIa-IIa is an important platelet receptor for collagen.
◦ α5β1 receptors play a complimentary role in platelet functions; they facilitate
platelet adhesion to fibronectin
◦ α6β1 integrin mediates platelet adhesion to laminin which is found in the basement
membranes and extracellular matrix
11

12. ◦ Glycoprotein Ia / IIa complex (GPIa / IIa =
integrin α2β1)
◦ It consists of two subunits
(α2 and β1). The α2 subunit
includes a domain
homologous to von
Willebrand factor domain
binding to collagen. The
β1 subunit has four cysteine-
rich regions and a structure
similar to other β-integrins.
12

13. β2 family
◦ αLβ2(CD102) is also known as intercellular adhesion molecule 2 (ICAM-2). It
is the only known member of β2 integrin family. It has approximately 3,000
copies on the surface of the platelets
◦ It is considered important for platelet adhesion to neutrophils and also for
platelet-leukocyte interaction
β3 family
◦ αIIbβ3 (CD41/CD61)also known as GPIIb-IIIa complex, is present only on the
platelets and is the most abundant platelet adhesion receptor.
◦ Resting platelets express 80,000-100,000 molecules of αIIbβ3 on their surface
13

14. Leucine-rich repeats (LRR) receptors
◦ It is a protein structural motif
composed of repeating 20-30 amino
acids which are rich in the
hydrophobic amino acid leucine
◦ LRR motifs are the most important
receptors of platelets that include
GPIb-IX-V complex, toll-like receptors
(TLR) and matrix metalloproteinases
(MMP).
14
Response

15. ◦ GPIb-IX-Vcomplex is the second most common platelet receptor after
integrin αIIbβ3, with approximately 50,000 copies per platelet. GPIb-IX-V
complex is instrumental in the initiation and propagation of both hemostasis
and thrombosis.
◦ Toll Like Receptors(TLRs) are transmemebrane proteins consist of a Low
Density Lipoprotein Receptor Protein extracellular domain, a transmembrane
region and a Toll-IL-1R domain
◦ Four types of TLRs i.e. 1, 2, 4 and 6 have been identified on platelets.
◦ TLRs play an important role in innate immunity by their ability to identify the products
of bacteria, viruses, protozoa and fungi. After identification of these products, TLRs
activate intracellular signaling pathways to induce an inflammatory response
15

17. Selectins
◦ These receptors are not only present on platelets, they are also found on
endothelial cells and lymphocytes.
◦ Members of selectin family of platelets include P-selectin, C-type lectin-like
receptor-2 (CLEC-2) and CD 72.
◦ P-Selectin, (CD62P), granule membrane protein (GMP) 140 or platelet
activation-dependent granule-external membrane(PADGEM) is a glycoprotein
of 140 kDa
◦ It is present in α-granules of resting platelets and is translocated to the plasma
membrane after activation
17

18. ◦ P-selectin attaches neutrophils
and monocytes to the platelets
and endothelial cells. It also
recruits monocyte-derived pro-
coagulant microparticles that
contain P-selectin glycoprotein
ligand-1(PSGL-1) and tissue factor
and helps in thrombus formation
18

19. Tetraspanins
Tetraspans or the transmembrane 4 superfamily
◦ This group includes CD63, CD9 and CD53.
◦ CD63 or lysosomal membrane-associated glycoprotein-3 (LAMP-3) is a 53 kDa lysosomal
membrane protein that appears on the surface of the activated platelets after release reaction.
◦ CD63 modulates platelet spreading and platelet tyrosine phosphorylation on immobilized
fibrinogen
◦ CD63 is an extremely reliable marker for in vivo platelet activation
19

20. Transmembrane receptors
◦ This is a major agonist receptor family which is well expressed on the surface of the
platelets.
◦ These receptors include ADP and thrombin receptors (PAR receptors).
◦ Adenosine Diphosphate (ADP) receptors:-
◦ ADP Secreted from the dense granules of platelets and damaged red cells after stimulation and binds to one
of the purinergic receptors
◦ There are 2 types of purinergic receptors in platelet membrane which are P2Y and P2X1
◦ Activation of P2Y(1) and P2Y(12) receptors, through secreted ADP that is stimulated by agonists such as
thrombin, thromboxane and collagen, is a major mechanism of platelet activation.
◦ P2X1 receptors also participate in platelet shape change and potentiation of calcium mobilization.
20

21. Thrombin receptors (PAR receptors).
◦ The four mammalian members of the protease-activated receptor (PAR)
family PAR1, PAR2, PAR3, and PAR4 are encoded by the genes F2R, F2RL1,
F2RL2, and F2RL3 respectively.
◦ Human PAR1 was discovered in 1991 as a key thrombin receptor on platelets
◦ Although human and mouse PAR2 genes are homologous to PAR1 genes,
PAR2 is not responsive to thrombin. Unexpected responses of platelets to
thrombin in PAR1 knockout mice lead to the discovery of the thrombin
receptors PAR3 and PAR4
◦ G protein-coupled signaling induced by PAR activation
21

22. Transmembrane receptors
PKA

23. Prostaglandin receptors
◦ Platelets have receptors for prostaglandins that play important modulatory
functions, thromboxane receptors, prostacyclin(PGI2), PGD2 and PGE2
receptors and PGE2 are important prostaglandin receptors.
◦ Thromboxane receptors:- These receptors activate phospholipase A2 and
phospholipase C through signal transduction by G proteins. Following the
stimulation by agonists, TXA2/PGH2 receptors amplify platelet activation by
autocrine mechanism.
23

24. Tyrosine kinase receptors
◦ Platelet tyrosine kinase receptors include the following members.
◦ Thrombopoietin receptors(CD110) belong to tyrosine kinase receptor family with a
molecular weight of 80-84 kDa. Although the number of thrombopoietin receptors is low
i.e. 25-224 per platelet, their affinity for thrombopoietin is very high.
◦ Platelet-derived growth factor receptors (PDGF) are α-receptors. Binding of PDGF to
its receptor initiates tyrosine phosphorylation based signaling cascade.
24

25. Serotonin receptors
◦ 5-hydroxytryptamin 2A (5-HT2A) is a major receptor.
◦ Interaction of 5-HT2A with serotonin initiates calcium signalling. Platelet activation
releases serotonin from dense granules that amplify release reaction and platelet
aggregation.
◦ Serotonin itself cannot cause platelet aggregation but it enhances aggregation induced by
other agonists e.g. ADP and thrombin (mechanism is still unclear)
◦ Serotonin also causes vasoconstriction of the blood vessels with damaged endothelium and
promotes thrombus formation
25

26. 26

27. Platelet receptor family Different members of the family
Integrins
Adrenaline Receptor: 2 1(GPIa/IIa)
Fibrinogen Receptor: 2 3(αIIbβ3)
Leucine-Rich Repeated Receptors
VWF receptor: Glycoprotein Ib/IX/V
Toll Like Receptors
G protein coupled Receptors
Thrombin Receptors: PAR-1 and PAR-4
ADP Receptors: P2Y1, and P2Y12
TxA2 Receptors: TP and TP
Immunoglobulin Ig Superfamily related
Collagen Receptor: GpVI
Ig Comlex Receptor: FcγRIIA
C-type lectin Receptors
P-selectin
Podoplanin Receptor: CLEC-2
Tyrosine Kinase Receptors
Thrombopeietin Receptor (c-MPL)
GAS6 Receptors: Tyro3, Axl, and Mer
Eph receptor kinases: EphA4 and EphB1
Insulin-like growth factor-1 Receptor
Miscellaneous
CD63, CD36, P-selectin ligand1, TNF
receptor type, etc
27

28. Hemostasis (Haemostasis)
◦ It is a process to prevent and stop bleeding.
◦ It is the first stage of wound healing. This involves coagulation, blood
changing from a liquid to a gel.
28
Steps involved in Hemostasis
Vascular
spasms
Platelet plug
formation
Blood
clotting
Fibrinolysis

29. Vascular spasms
(vasospasms)
Primary hemostasis
◦ Contraction of vessel
◦ Probably caused by damage to
smooth muscle ,by the substances
released from the activated
platelets, and by reflexes initiated
by pain receptors.
◦ Smooth muscle contraction by IP3
pathway
29

31. Platelet plug formation
◦ Hemostatic plug or platelet thrombus
◦ Part of primary hemostasis
◦ 3 steps:-
◦ Platelet activation
◦ Platelet adhesion
◦ Platelet aggregation
31

32. ◦ Platelet activation
◦ Under normal physiological conditions, blood flows through the body without any noticeable
aggregation of platelets
◦ Any discontinuity detected in the vascular endothelium triggers an automatic response in the
clotting system, which in turns stimulates thrombin production which causes platelet aggregation
◦ Platelet adhesion
◦ Once platelets are activated, when they come across injured endothelium cells, the von
Willebrand factor (vWF) and fibrinogen will act as anchors to allow platelets to adhere onto the
vessel wall
◦ Platelet aggregation
◦ After platelets make contact with the focal point of the vascular injury, they begin to interact with
each other to form a platelet aggregate. Platelet aggregation is mainly mediated by β3 (αIIbβ3)
integrin and its ligands, such as vWF and fibrinogen
◦ While platelet membranes have binding sites for fibrinogen, they must be induced by thrombin.
Thrombin triggers the binding of the adhesive platelets with vWF and fibrinogen.
32

33. Process of plug formation
Platelet contact & stick to parts of the damaged blood vessel with the help of von
Willebrand factor (VWF) (Platelet adhesion)
Adhesion makes them activated which causes characteristic changes. They extend many
projections that enable them to stick and contact to other platelets and they begin to
release the contents of their vesicles (platelet release reaction)
ADP makes other platelets sticky which recruits and activates another platelet to gather
(Platelet aggregation)
The accumulation of platelets is known as platelet plug or thrombus
33

34. • GPVI and GPIb are platelet receptors
that bind to collagen and vWF,
platelet to adhere to the
subendothelium of a damaged blood
vessel.
• PAR-1 and PAR-4 are Protease
Activated Receptors that respond to
thrombin (IIa) ;
• P2Y1 and P2Y12 are receptors for ADP;
• When stimulated by agonists, these
receptors activate the fibrinogen-
binding protein GPIIb/ IIIa and COX-1
to promote platelet aggregation and
secretion
• TXA2 (thromboxane A2) is the major
product of COX-1 involved in platelet
activation
• Prostacyclin (PGI2), synthesized by
endothelial cells, inhibits platelet
activation.
34

35. Blood clotting
◦ The process of liquid to gel formation.
◦ It is a series of reactions that culminates in the formation of fibrin threads.
◦ If blood clots too easily in an undamaged vessel, results can be Thrombosis
◦ If blood clots too long to clot, Hemorrhage can occur.
◦ Procoagulant = The precursor of various blood factors necessary for coagulation
35

36. ◦ Clotting involves various substances known as clotting factors.
◦ It is a complex cascade of enzymatic reactions in which each
clotting factor activates many molecules of the next one in a fixed
sequence
◦ Kininogen, a high molecular weight plasma protein also serves as a
cofactor in the conversion of XIIa into XI
36

37. Pathways for clotting
• Extrinsic pathway
• Intrinsic pathway
• Common pathway
37

38. 38

39. Extrinsic pathway
◦ In the case of injury, the cells outside the blood vessels secrete a tissue
protein known as Tissue Factor (TF) or Thromboplastin into the blood
and initiates the formation of prothrombinase
◦ Tissue factor serves as a cofactor with factor VII to facilitate the
of factor X. Alternatively, factor VII can activate factor IX, which, in turn,
can activate factor X
◦ In the presence of 𝐶𝑎+2, TF begins a sequence of reactions that
ultimately activates the clotting factor X.
◦ Once factor X is activated ,it combines with the factor V in the presence
of 𝐶𝑎+2
to form the active enzyme Prothrombinase, completing the
extrinsic pathway.
39

40. Intrinsic pathway
◦When the blood comes in the contact of collagen of the
damaged vessel(or the glass sides of the blood collecting
tubes) clotting factor XII is activated which begin a sequence
of reactions that eventually activates clotting factor X
◦The enzyme form of factor XII (factor XIIa) catalyzes the
conversion of factor XI to its enzyme form (factor XIa).
◦Factor XIa catalyzes the conversion of factor IX to the
activated form, factor IXa, in a reaction that requires calcium
ions.
40

41. ◦ Factor IXa assembles on the surface of membranes in complex with factor
VIII; the factor IXa–factor VIII complex requires calcium to stabilize certain
structures on these proteins associated with their membrane-binding
properties.
◦ Factor X binds to the factor IXa–factor VIII complex and is activated to
factor Xa. Factor Xa forms a complex with factor V on membrane surfaces
in a reaction that also requires calcium ions
◦ Once factor X is activated, it combines with factor V to form the active
enzyme Thrombinase, completing the intrinsic pathway.
41

42. Common pathway
• Involves fibrinogen (factor I), factors II (prothrombin), V, X
• Prothrombinase marks the beginning of the common pathway.
• Thrombin, in the presence of 𝐶𝑎+2, converts fibrinogen, which is loose fibrin threads,
which is insoluble to fibrin monomers
• Remaining fibrin monomers polymerize to form fibrin
• Thrombin also binds to antithrombin, which inhibits thrombin to prevent excessive
clotting
• Thrombin may also activate factor XI (part of intrinsic pathway), factors V, VIII, XIII, XI
and platelets
• Factor XIII cross links fibrin to increase stability of fibrin clot
42

43. 43

44. Number Name Pathway of activation
I Fibrinogen Common
II Prothrombin Common
III Tissue Factor(Thromboplastin) Extrinsic
IV calcium ions All
V Proaccelerin, labille factor Extrinsic and Intrinsic
VII
Serum prothrombin convertor accelerator (SPCA),
stable factor, or proconvertin Extrinsic
VIII Antihemophilic factor (AHF) Intrinsic
IX Christmas factor, plasma thromboplastin component (PTC) Intrinsic
X Stuart factor, thrombokinase Extrinsic and Intrinsic
XI
Plasma thromboplastin antecedent (PTA),
antihemophilic factor C Intrinsic
XII Hageman factor, contact factor, anti hemophilic factor D Intrinsic
XIII Fibrin stablizing factor Common
44

45. Fibrinolysis
◦ The fibrinolytic system dissolves small,
inappropriate clots;
◦ It also dissolves clots at a site of damage once
the damage is repaired . Dissolution of a clot is
called fibrinolysis.
◦ When a clot is formed ,an inactive plasma
enzyme called plasminogen is incorporated
into the clot.
◦ Both body tissues and blood contain
substances that can activate plasminogen to
plasmin (or fibrinolysin), an active plasma
enzyme.
◦ This plasmin can dissolve the clot by digesting
fibrin threads and inactivating substances like
fibrinogen, prothrombin, and factors V and XII.
45

46. ◦ The fragments of the disintegrating fibrin in the clot are called fibrin
degradation products (FDP) (consist of pieces of crosslinked fibrin).
◦ One of the final fibrin degradation products produced is D-dimer, which
can be measured in a blood sample when present. The level of D-dimer
in the blood can significantly rise when there is significant formation and
breakdown of fibrin clots in the body.
◦ Endothelial cells and white blood cells produce a prostaglandin called
prostacyclin that opposes the actions of thromboxane A2
◦ Prostacyclin is a powerful inhibitor of platelet adhesion and release.
46

47. 47

48. DISORDERS OF HAEMOSTASIS AND
COAGULATION
48

49. ◦Congenital disorders
◦ HAEMOPHILIA A
◦ HAEMOPHILIA B
◦ Von WILLEBRAND’S disease
◦ Deficiencies of factor XI and XII
◦ Deficiencies of factor VII, V and
thrombin
◦ Disorders of fibrinogen activation or
hypofibrinogenemia or
dysfibrinogenemia
◦ Factor XIII deficiency
◦Acquired disorders
◦ Acquired coagulation factor
inhibitors
◦ Liver disease
49

50. Hemophilia A and B
◦ Abnormal or exaggerated bleeding
and poor blood clotting
◦ Hemophilia A and B are inherited in
a X-linked recessive genetic pattern
and are therefore much more
common in males
◦ Bleeding is prolonged for hours or
days after injury.
◦ Hemophilia A is caused by mutation
in the gene for factor VIII
◦ Hemophilia B ) results from a
deficiency of factor IX
50

51. ◦ A condition referred to as hemophilia C
involves a deficiency of clotting factor XI
◦ Hemophilia can result in:
o Bleeding within joints that can lead to chronic joint disease and
pain
o Bleeding in the head and sometimes in the brain which can
cause long term problems, such as seizures and paralysis
o Death can occur if the bleeding cannot be stopped or if it occurs
in a vital organ such as the brain
51
Hemophilia
A; 80%
Hemophilia
B; 19%
Hemophilia
C; 1

52. Treatment
◦ The best way to treat hemophilia is to replace the missing blood clotting factor so that
the blood can clot properly. This is done by infusing (administering through a vein)
commercially prepared factor concentrates.
◦ Plasma-derived Factor Concentrates (Cryoprecipitate)
52

53. Drugs used to treat Hemophilia A
Antihemophilic factor
Generic name: antihemophilic factor systemic
Brand names: Advate, Recombinate, Eloctate, Xyntha,
NovoEight, Hemofil-M, Kogenate FS, Adynovate, Afstyla, Helixate
FS, Esperoct, Jivi, Nuwiq, Koate-DVI, Hyate:C, Kovaltry, Monoclate-P
, Obizur, Koate
Drug class: miscellaneous coagulation modifiers
Desmopressin
Generic name: desmopressin systemic
Brand names: DDAVP
, Stimate
Drug class: antidiuretic hormones
Tranexamic acid
Generic name: tranexamic acid systemic
Brand name: Cyklokapron
Drug class: miscellaneous coagulation modifiers
Antihemophilic factor / von willebrand factor
Generic name: antihemophilic factor / von willebrand factor systemic
Brand names: Humate-P
, Alphanate
Drug class: miscellaneous coagulation modifiers
Coagulation factor VIIa
Generic name: coagulation factor viia systemic
Brand names: NovoSeven RT, Sevenfact
Drug class: miscellaneous coagulation modifiers

54. Dosing of Antihemophilic factor
◦ The half life of infused factor is usually 8-12 hours. Incremental
recovery (i.e., the amount increase of factor activity per unit per kg) and
half life vary from patient to patient.
◦ Target levels by hemorrhage severity are as follows:
• Mild hemorrhages (i.e., early hemarthrosis, epistaxis, gingival bleeding): Maintain
an FVIII level of 30%
• Major hemorrhages (i.e., hemarthrosis or muscle bleeds with pain and swelling,):
Maintain an FVIII level of 50%
• Life-threatening bleeding episodes (i.e., major trauma or surgery, advanced or
recurrent hemarthrosis): Maintain an FVIII level of 80-90% until stabilization; after
stabilization, maintain levels above 40-50% for a minimum of 7-10 days
54

55. Von Willebrand’s disease
(vWD)
oFirst described in Aland Islands by Erik von Willebrand (1870-1949).
oVWF is a complex multimeric glycoprotein with two important roles in hemostasis:
o It binds to platelet receptors, bridging them to other platelets and subendothelial tissue that is exposed, and
o Acts as a carrier protein for the coagulation factor VIII (FVIII), thus preventing its proteolytic inactivation in the plasma
oStored inside specialized storage organelles, the Weibel–Palade bodies of endothelial
cells and α‐granules of platelets, VWF is released into circulation both constitutively and
on stimulation
oMyriad substances act as secretagogues of the VWF, including histamine, thrombin,
epinephrine and vasopressin
oVon Willebrand’s disease occurs as a result of decrease in plasma levels or defect in von
Willebrand factor
55

56. ◦ People with vWD sometimes experience heavier-than-normal bleeding from injury,
surgery, and, in women, menstrual flow and childbirth.
◦ Inherited forms are of three major types. They are type 1, type 2, and type 3; in which
type 2 is sub-divided into 2A, 2B, 2M, 2N.
◦ Type 1 is more prevalent than all other types affecting up to 1% of the population.
◦ Mucocutaneous bleeding is mild in type 1 whereas it is mild to moderate in types 2A,
2B, and 2M.
◦ Type 2N has similar symptoms of hemophilia. Type 3 has Total or near‐total absence
of VWF which is the most severe but fortunately a rare type
◦ The pathophysiology of each type depends on the qualitative or quantitative defects
in von Willebrand factor.
56

57. Inherited vWD
◦ Type 1 is inherited as autosomal
dominant and is characterized by
quantitative defect in vWF
◦ Type 2 has variable inheritance and
there is qualitative defect in vWF
◦ Type3 is autosomal recessive
disease with absent levels of vWF
Acquired vWD
• Acquired vWD is due to the rapid
clearance of vWF from the plasma
after it forms a complex with its
antibody
57

58. Treatment
◦ Desmopressin: It boost levels of von Willebrand factor (VWF) in the blood.
Dose 4mcg/mL (inj),0.1mg (tab)
• VWF infusions: More often for surgical procedures. Some patients with severe
forms of von Willebrand disease receive regular VWF infusions or
prophylactic therapy to maintain normal levels of the VWF protein in their
blood.
• Antifibrinolytics: Agents such as tranexamic acid and aminocaproic acid
inhibit the interaction of plasminogen with fibrin, thus preventing the
degradation of the fibrin clot
• Birth control pills: The estrogen content in these pills will cause an increase in
the level of VWF in the blood, and thus provide some protection in women
with heavy menstrual bleeding
58

59. Factor XIII deficiency
◦ Factor XIII deficiency is a rare, genetic bleeding disorder
characterized by deficiency of clotting factor XIII
◦ Individuals with factor XIII deficiency form blood clots like normal, but
these clots are unstable and often break down, resulting in
prolonged, uncontrolled bleeding episodes
◦ FXIII consists of two subunits: subunit A (F13A1) and subunit B( F13B )
Most of the Factor XIII deficiency states are caused by mutations in
subunit A; very few have a mutation in subunit B.
◦ Factor XIII deficiency is inherited as an autosomal recessive disorder.
59

60. ◦ Symptoms commonly associated with factor XIII deficiency include
ochronic nosebleeds (epistaxis),
obleeding from the gums,
odiscoloration of the skin due to bleeding underneath the skin
(ecchymoses),
oSolid swellings of congealed blood (hematomas)
60

61. TREATMENT
◦ Factor XIII concentrate, which is a blood product that contains a
concentrated form of factor XIII, is used to treat individuals with factor
XIII deficiency. (Brand name: Corifact) - Manufactured by CSL Behring
L.L.C.
◦ In the past, individuals with factor XIII deficiency were treated with fresh
frozen plasma or cryoprecipitates
◦ Coagulation factor XIII A-subunit (recombinant) (Brand name: Tretten) -
Manufactured by Novo Nordisk, Inc.
FDA-approved indication: Routine prophylaxis of bleeding in patients
with congenital Factor XIII A-subunit deficiency.
61

62. Thrombocytopenia
◦ Thrombocytopenia is a condition in which you have a
low blood platelet (less than 150,000 platelets per
microliter of circulating blood)
◦ Circulating platelets are reduced by one or more of the
following processes: trapping of platelets, decreased
platelet production or increased destruction of platelets
◦ Platelets are produced in your bone marrow. Factors
that can decrease platelet production include:
oLeukemia and other cancers
oAnemia
oViral infections, such as hepatitis C or HIV
oChemotherapy drugs and radiation therapy
oHeavy alcohol consumption
62

63. Increased breakdown of platelets
◦ Some conditions can cause your body to use up or destroy platelets faster than
they're produced, leading to a shortage of platelets in your bloodstream.
Examples of such conditions include:
oImmune thrombocytopenia. Autoimmune diseases, such as lupus and rheumatoid
arthritis, cause this type. The exact cause of this condition isn't known.
oHemolytic uremic syndrome. This rare disorder causes a sharp drop in platelets,
destruction of red blood cells and impairs kidney function (E.coli infection)
oMedications. Certain medications can reduce the number of platelets in your
blood. Sometimes a drug confuses the immune system and causes it to destroy
platelets. Examples include heparin, quinine, sulfa-containing antibiotics and
anticonvulsants.
63

64. Thrombotic thrombocytopenic purpura
◦ A rare disorder that causes blood clots (thrombi) to form in small blood vessels
throughout the body. These clots can cause serious medical problems if they
block vessels and restrict blood flow to organs such as the brain, kidneys, and
heart
◦ Because many platelets are used to make clots in people with thrombotic
thrombocytopenic purpura, fewer platelets are available in the bloodstream which
causes thrombocytopenia
64

65. Recent Advancements
◦ Researchers are studying the effectiveness of a genetically engineered
(recombinant) form of factor XIII for the treatment of individuals with factor
XIII deficiency.
◦ Initial studies have shown the drug to be effective in preventing bleeding
episodes potentially associated with factor XIII deficiency. Because it is
artificially created in a lab, recombinant factor XIII does not contain human
blood or plasma and, consequently, there is no risk of blood-borne viruses or
other such pathogens.
◦ The drug has not yet received approval from the FDA for the treatment of
individuals with factor XIII deficiency.

66. ◦ A bispecific monoclonal antibody (emicizumab) has recently been
approved for prophylaxis of hemophilia A patients with or without
FVIII inhibitors
◦ The drug is designed to bridge activated Factor IX and coagulation
Factor X, in order to restore the function of the missing activated FVIII
necessary for effective hemostasis.
◦ Emicizumab has no structural correlation or sequential homology with
Factor VIII and therefore does not induce or potentiate the
development of FVIII inhibitors. Recent studies evaluating emicizumab
prophylaxis showed clinically meaningful bleed control.
66

67. Coagulants
67

68. Classification of Coagulants
1) Agents acting locally (thrombin)
2) Transfusional agents
1) Human fibrinogen
2) Antihemophilic globulin
3) Plasma or blood
3) Non transfusional agents
1) Vitamin K
2) Epsilon Amino Caproic Acid (EACA)
3) Tranexamic acid
4) Ethamsylate
5) Aprotinin
6) Desmopressin
68

69. Non Transfusional Agents
Vitamin K
◦ It is a fat-soluble dietary principle required for the
synthesis of clotting factors
◦ Vit. K1 was isolated from alfalfa grass in 1939
◦ In nature, vit K2 (menaquinone) is produced only
by bacteria, that is found in humans and derived
from intestinal flora.
◦ Synthetic compounds have been produced and
labelled as K3
◦ It has a basic naphthoquinone structure with or
without side chain at position 3
◦ Dietary sources are green leafy
vegetables(cabbage, spinach, etc.)
69

70. ◦ Vitamin K serves as a cofactor for the enzyme gamma-glutamate
carboxylase (GGCX), (found in the endoplasmic reticulum) and that
catalyzes the conversion of the amino acid glutamate into gamma-
carboxyglutamyl ( Gla ).
◦ The oxidation of vitamin K hydroquinone provides the energy required
for this carboxylation reaction.
◦ Gla-residues form strong calcium-binding groups in the proteins to
which they are attached and in all cases in which their function is known
the Gla-residues are essential for the function of these proteins .
70

71. ◦ All Gla-proteins known today contain multiple Gla-residues per
molecule ranging from three in the bone Gla-protein
osteocalcin to 10 in prothrombin and as much as 16 in Gla-rich
protein (GRP).
◦ The position of the Gla-residues within the respective proteins is
well-defined, but in the case of vitamin K insufficiency, under-
carboxylated or even uncarboxylated Gla-proteins are
synthesized which lack biological activity.
71

72. ◦ Since no specific receptors for vitamin K have been discovered at
the outer membrane of various cells, it is likely that LDL-bound
vitamin K is taken up by the cells via the LDL-receptors.
◦ Fat soluble forms of Vit K (K1 and K2) are absorbed from intestine
in the presence of bile salts .After absorption they gets
concentrated in liver .
◦ When the levels of bile decreases, the level of vit-k dependent
clotting factors also decreases within some weeks.
72

73. Tranexamic acid
◦ Tranexamic acid (TXA) synthetic lysine analogue reduces bleeding by
inhibiting the enzymatic degradation of fibrin blood clots
(antifibrinolytic agent)
◦ TXA inhibits fibrinolysis by reducing the binding of plasminogen to
fibrin.
◦ TXA may reduce bleeding through other mechanisms. For example,
TXA may improve platelet function or the exposure of platelets with
plasmin induces platelet activation
◦ Oral administration (1 tablet = 0.5 g).
◦ Intravenous administration (1 ampoule = 5 ml = 0.5 g) in fibrinolysis
73

74. Desmopressin
◦ Analog of vasopressin that exerts a substantial hemostatic effect by inducing the
release of von Willebrand factor from its storage sites in endothelial cells.
◦ Useful in treating or preventing bleeding episodes in patients with vWD,
hemophilia A and platelet function defects.
◦ Vasopressin is a secretagogue of vWF. This hormone functions through two
receptors, termed V1 and V2, which activate different intracellular second
messenger (V1 activate phospholipases via Gq and V2 receptor that activates
adenylyl cyclase by interacting with Gs).
◦ Agonist activity at V2 receptors leads to a rise in intracellular concentrations of
cyclic adenosine monophosphate, which in turn induces exocytosis of VWF from
its storage sites (i.e., Weibel–Palade bodies) into the circulation
74

75. ◦Desmopressin (1‐desamino‐8‐d‐arginine vasopressin,
also abbreviated DDAVP) activates only V2 receptors
and thus lacks its vasoconstrictor and uterotonic
properties
◦Although originally designed for the treatment of
diabetes insipidus, desmopressin emerged as a
hemostatic agent
75

76. Styptics (Thrombin)
◦ It acts as local hemostatic that is used to stop bleeding in a local
site
◦ Thrombin obtained from bovine plasma may be applied as dry
powder or freshly prepared solution
◦ It has both activating and inhibiting effects-
◦ Thrombin acts to convert factor XI to XIa, VIII to VIIIa, V to
Va, fibrinogen to fibrin, and XIII to XIIIa.
◦ Thrombin bound to thrombomodulin activates protein C, an
inhibitor of the coagulation cascade
76

77. 77

78. Styptics (Thrombin)
◦ In the blood coagulation pathway, thrombin acts to convert factor XI to
XIa, VIII to VIIIa, V to Va, fibrinogen to fibrin, and XIII to XIIIa.
◦ Thrombin also promotes platelet activation and aggregation via activation
of protease-activated receptors on the cell membrane of the platelet.
◦ Thrombin bound to thrombomodulin activates protein C, an inhibitor of the
coagulation cascade. The activation of protein C is greatly enhanced
following the binding of thrombin to thrombomodulin, an integral
membrane protein expressed by endothelial cells. Activated protein C
inactivates factors Va and VIIIa.
78

79. Advancement
◦ During recent years, monoclonal antibodies specifically
recognizing carboxylated Matrix Gla proteins (cMGP) and
uncarboxylated MGP (ucMGP) have been created (VitaK,
Maastricht, the Netherlands) instead of using Vit K.
◦ TXA reduces surgical bleeding and in 2010, the CRASH-2 trial
showed that TXA reduces death due to bleeding in trauma
patients ( Roberts & Prieto-Merino, 2014). TXA also has the
potential to reduce death due to bleeding in Postpartum
haemorrhage (PPH). The WOMAN trial is investigating the effect
of TXA on mortality and morbidity in women in PPH
79

80. Anti coagulants
80

81. ◦ Anti coagulant drugs used to reduce coagulability of blood
◦ Thrombosis is prevented by several regulatory mechanisms that
require healthy vascular endothelium
◦ Nitric oxide and prostacyclin synthesized in healthy endothelium
inhibits platelet activation
◦ Antithrombin is a plasma protein that inhibits coagulation
enzymes of the extrinsic , intrinsic and common pathways
◦ Heparan sulfate proteoglycans synthesized by the endothelial
cells enhance the activity of antithrombin by about 1000 folds
81

82. ◦ Another inhibitory mechanism involves protein C, a plasma zymogen
that is homologous to factors II, VII,IX and X
◦ Protein C binds to Endothelial protein C receptor (EPCR), which presents
it to the thrombin-thrombomodulin complex for activation.
◦ Activated C protein then dissociates from EPCR and in combination with
protein S, its non-enzymatic Gla containing cofactor, activated protein C
degrades factors Va and VIIIa
◦ Congenital or acquired deficiency of protein C or protein S is associated
with an increased risk of venous thrombosis
82

83. 83

84. CLASSIFICATION
OF
ANTICOAGULANTS
PARENTERAL
ANTICOAGULANTS
Indirect thrombin inhibitors
Heparin, Fondaparinux, Low
Molecular Weight Heparins
(LMWH)
Direct thrombin inhibitors Bivalirudin, Argatroban
ORAL ANTICOAGULANTS
Vitamin K antagonists
Warfarin, Bishydroxycoumarin
(Dicumarol), Acenocoumarol
Direct Factor Xa Inhibitors Rivaroxaban, Apixaban
Oral Direct Thrombin
Inhibitors
Dabigatran etexilate
84

85. Indirect thrombin inhibitors
Heparin
◦ McLean, a medical student, discovered in 1916 that
liver contains a powerful anticoagulant. Howell and
Holt (1918) named it ‘heparin’
◦ It is a glycosaminoglycan found in the secretory
granules of mast cells, is synthesized from UDP-
sugar precursors as a polymer of alternating D-
glucuronic acid and N-acetyl-D-glucosamine
residues.
◦ Heparin is commonly extracted from porcine
intestinal mucosa, which is rich in mast cells
◦ Various commercial heparin preparations have
similar biological activity (~150 USP units/mg).
85

86. 86

87. • Pentasaccharide binding to antithrombin induces a conformational change in
antithrombin that renders its reactive site more accessible to the target protease.
• This conformational change accelerates the rate of factor Xa inhibition
87

88. ◦ Heparin, LMWHs, and Fondaparinux have no intrinsic anticoagulant activity; rather they
bind to antithrombin and accelerate the rate at which it inhibits various coagulation
proteases
◦ Antithrombin is synthesized in liver and circulates in plasma at an approximate
concentration of 2.5 µM.
◦ Antithrombin inhibits activated coagulation factors, particularly thrombin and factor Xa,
◦ These agents can be used to initiate treatment of deep vein thrombosis and unstable
angina
◦ The theoretic benefit of adding in the treatment of unstable angina is that it may prevent
the propagation of an established thrombus, allowing time for endogenous fibrinolysis to
occur. The drug presumably should act synergistically with the antiplatelet effects of aspirin
to reduce coronary artery obstruction and ischemia, ultimately lessening morbidity and
mortality (Doi: 10.1136/ewjm.173.2.138)

89. Direct thrombin inhibitors
◦ Bivalirudin is a synthetic 20-amino acid
polypeptide
◦ Binds firmly to the catalytic as well as
substrate recognition sites of thrombin
◦ IV administered
◦ Half life= 25 min
◦ Used as an alternative to heparin in
patients with cardiopulmonary bypass
surgery
◦ Can be used in patients with heparin
induced thrombocytopenia
◦ Argatroban is a synthetic compound
based on the structure of L-arginine
◦ Binds reversibly to the catalytic site of
thrombin, but not the substrate
recognition site
◦ IV administered
◦ Half life= 40-50min
89

91. Vitamin K antagonists
WARFARIN
Brief history
◦ A hemorrhagic disease is described in in cattle in 1924 due to feeding them on spoiled
food . The disorder was due to the prothrombin deficiency and the toxic principle was
identified as bishydroxycoumarin (dicoumarol)in 1939
◦ Researchers worked through a list of 150 variations of coumarin, and number 42 was
found to be particularly potent. The compound was named 'warfarin' after the funding
agency, and was successfully marketed in 1948 as a rodenticide
◦ Examples:- Warfarin, Bishydroxycoumarin (Dicumarol), Ethyl-biscoumacetate,
Acenocoumarol
91

92. ◦ Factors II, VII, IX, and C and proteins
C and S are synthesized by
carboxylation reaction which requires
CO2, O2 and reduced vitamin K and is
catalyzed by γ-glutamyl carboxylase
◦ Reduced vit k must be generated from
the epoxide form for sustained
carboxylation and synthesis of
functional proteins
◦ The enzyme that catalyzes this
reaction, VKOR (vit k epoxide
reductase) is inhibited by therapeutic
doses of warfarin.
92

93. 93

94. Direct Oral Inhibitors
94
Oral
Direct
Thrombin
Inhibitors
• Dabigatran etexilate is a synthetic prodrug
which is rapidly converted into dabigatran
which blocks the active site of free and clot
bound thrombin.
• In turn, this blocks conversion of fibrinogen
to fibrin, and platelet activation.
Direct
Factor Xa
Inhibitors
• Rivaroxaban, Apixaban, and Edoxaban
inhibit free and clot-associated factor Xa,
which results in reduced thrombin
generation
• In turn, platelet aggregation and fibrin
formation are suppressed
Sometimes these agents cause
excessive bleeding in some individuals
If it happens, reversal agents can be
used .
Examples are:-
• Idarucizumab (Dabigatran)(licensed)
• Andexanet alfa (Rivaroxaban,
Apixaban, and Edoxaban )(in phase 3
study)
• Ciraparantag is in earlier stages of
development

95. Fibrinolytic drugs
◦ Dissolve blood clots by activating plasminogen, which forms a cleaved
product called plasmin.
◦ Plasmin is a proteolytic enzyme that is capable of breaking cross-links
between fibrin molecules, which provide the structural integrity of blood
clots.
◦ Because of these actions, thrombolytic drugs are also called "plasminogen
activators" and “thrombolytic drugs."
95

96. ◦ There are three major classes of fibrinolytic drugs: tissue
plasminogen activator (tPA), streptokinase (SK), and urokinase
(UK).
◦ While drugs in these three classes all can effectively dissolve
blood clots, they differ in their detailed mechanisms in ways that
alter their selectivity for fibrin clots.
◦ The figure to the right illustrates the fibrinolytic mechanisms for
tPA and SK
◦ Tissue plasminogen activator produces clot lysis through the
following sequence:
1. tPA binds to fibrin on the surface of the clot
2.Activates fibrin-bound plasminogen
3.Plasmin is cleaved from the plasminogen associated with the fibrin
4.Fibrin molecules are broken apart by the plasmin and the clot dissolves
96

97. Streptokinase and Urokinase
◦ Streptokinase (SK) is used in acute myocardial infarction, arterial and venous thrombosis, and pulmonary
embolism. These compounds are antigenic because they are derived from streptococci bacteria.
• Natural SK is isolated and purified from streptococci bacteria. Its lack of fibrin specificity makes it a less
desirable thrombolytic drug than tPA compounds because it produces more fibrinogenolysis.
• Anistreplase (Eminase®) is a complex of SK and plasminogen. It has more fibrin specificity and has a
longer activity than natural SK; however, it causes considerable fibrinogenolysis.
◦ Streptokinase causes a systemic thrombolytic state that usually resolves within 48 hours of
administration.
◦ The half-life of streptokinase is between 23 and 29 minutes; however, it has been reported as high as 89
minutes in some instances
◦ Urokinase (Abbokinase®; UK) is sometimes referred to as urinary-type plasminogen activator (uPA)
because it is formed by kidneys and is found in urine. It has limited clinical use because, like SK, it
produces considerable fibrinogenolysis; however, it is used for pulmonary embolism.
◦ One benefit over SK is that UK is non-antigenic; however, this is offset by a much greater cost.
97

98. 98

99. Antiplatelet drugs
◦Platelet aggregates form the initial hemostatic plug of
vascular injury
◦Potent inhibitors of platelet function have been developed in
recent years
◦Example : Aspirin, dipyridamole
99

100. Advancement
◦ A new study reveals that the COVID-19 virus triggers production of
microscopic antibodies circulating through the blood, causing clots in people
hospitalized with the disease ad finally resulting in inflammation
100

102. General
processes
• Hemostasis
• Primary hemostasis
• Vascular spasms
• Platelet plug formation
• Secondary hemostasis
• Coagulation cascade
• Fibrinolysis

103. DISORDERS
103
• Hemophilia A and B
• Von Willebrand’s disease
• Factor XIII deficiency
• Thrombocytopenia
• Thrombotic thrombocytopenic purpura

104. Coagulants
• Vitamin k
• Transexanemic acid
• Desmopressin
• Thrombin

105. Anti coagulants
105
• Vitamin K antagonists (Warfarin)
• Factor Xa Inhibitors(Rivaroxaban,Apixaban)
• Thrombin Inhibitors(Heparin,)