FIBRINOLYSIS Flashcards
is defined as the dissolution of clot by plasmin.
Fibrinolysis
is derived from plasminogen, which is produced by the liver.
Plasmin
Dissolution of clot to restore and reestabish blood flow
FIBRINOLYSIS
Clot=
Thrombosis = ↑ Blood pressure = Aneurysm
-Dissolution of clots
FIBRINOLYSIS
-systematic, accelerating hydrolysis of fibrin by bound plasmin
FIBRINOLYSIS
-Proteins involved:
Plasminogen
Tissue plasminogen activator
Urokinase
Plasminogen activator inhibitor-1
a2-Antiplasmin Thrombin-activatable
fibrinolysis inhibitor
Plasma serine protease, plasmin digests fibrin/fibrinogen
Plasminogen
Serine protease secreted by activated endothelium, activates plasminogen
Tissue plasminogen activator
Serine protease secreted by kidney, activates plasminogen
Urokinase
Secreted by endothelium, inhibits tissue plasminogen activator
Plasminogen activator inhibitor-1
Inhibits plasmin
a2-Antiplasmin
Suppresses fibrinolysis by removing fibrin C-terminal lysine binding sites
Thrombin-activatable fibrinolysis inhibitor
: Serine protease; substrate for activation; activates plasmin (digests fibrin to fibrinogen)
Plasminogen
: digests fibrin/fibrinogen
Plasmin
: injured blood vessel that releases procoagulant substances like collagen and tissue factor
Activated endothelium
Endothelium → Activation of plasminogen →
TPA → Plasmin
: regulator of TPA/Urokinase plasminogen activator
Plasminogen activator inhibitor-1
: specifically inhibits free plasmin
a2-Antiplasmin
: activated by thrombin
TAFI
: form the kidneys and can also be produced by monocyte and macrophage
UPA
• Serine protease activated to plasmin
PLASMINOGEN
• Produced by the liver
PLASMINOGEN
• Structure: five glycosylated loops (kringles)
PLASMINOGEN
is made up of lysine amino acid
Plasminogen
: located at the C-terminal end of every loop
Lysine
allows binding to TPA or UPA in plasminogen to activate it
Lysine
binding site of the activators of plasminogen
Lysine
attaches lysine to activate plasminogen (FIBRINOLYTIC SYSTEM)
TPA/UPA
Other activators: (COAGULATION SYSTEM)
FXIIa, Kallikrein, and Thrombin + Protein C, Protein S, Protein Z, thrombomodulin
(EXOGENOUS)
urokinase and streptokinase
not produced by the body but can imitate the action of urokinase from the kidney
EXOGENOUS
synthetically produced outside the body
EXOGENOUS
can come from bacteria, medications, and food
EXOGENOUS
Functions of Plasmin
Promotes clot dissolution
Activates complement system
Fragments FXIIa
activated form of plasminogen, which digests the clot
Plasmin