What is Fibrinogen?
Fibrinogen (English: Fibrinogen, also known as fibrinogen) is a protein that can be dissolved in water. It is a protein with coagulation function synthesized by the liver. It is an important substance in the process of coagulation and thrombosis. [1] . Fibrin is a monomeric protein produced by thrombin removal of fibrinogens A and B in fibrinogen during the coagulation process. High fibrinogen is an important risk factor for various thrombotic diseases and is considered as a marker of disease status in the clinic.
- Fibrinogen is a protein with coagulation function mainly synthesized by hepatocytes. It is the highest coagulation factor in plasma. Fibrinogen has a molecular weight of about 340 kDa, and has a triple-spherical shape. It consists of three different peptide chains of , , and , with D regions at both ends and E regions in the middle. The D and E regions pass through three peptides in an alpha helix. Chain connected. Fibrinogen is an important reaction substrate for thrombosis and is involved in a key step in thrombosis. Fibrinogen forms fibrin monomers under the action of thrombin, fibrillary stabilizing factor (FXa), Ca 2+ and other coagulation factors, and covalently combines with each other to form fibrin multimers, whose chains are staggered and overlapped and covalently intersected. They form a stable fibrin network, and eventually capture red blood cells (RBC), platelets (PLT), 2-antiplasmin (2-AP) and other components to form a stable thrombus structure. [2]
- When platelets rupture, coagulation-activating enzymes are released, which catalyzes prothrombin into thrombin under the action of calcium ions. Thrombin coagulates fibrinogen, which is water-soluble in plasma, into fibrin, which is insoluble in water. Fibrin kinks other blood cells into clumps and coagulates into blood clots. Fibrinogen (Factor I) is a glycoprotein that circulates in the blood of vertebrates. During tissue and blood vessel damage, it is enzymatically converted to fibrin by thrombin, which is then converted to a fibrin-based blood clot. Fibrinogen mainly blocks blood vessels, preventing excessive bleeding. However, the fibrinogen product fibrin binds and reduces thrombin activity. This activity, sometimes called antithrombin I, is used to limit blood clotting. This loss or reduction of antithrombin 1 activity due to mutations in fibrinogen genes or low fibrinogen conditions can lead to excessive blood coagulation and thrombosis. Fibrin also mediates the proliferation of platelets and endothelial cells, the proliferation of tissue fibroblasts, capillary formation and angiogenesis, thereby promoting tissue revascularization, wound healing and tissue repair.
- A glycoprotein synthesized by the liver. Dimer composed of 6 peptide chains of , and with 610, 461 and 411 amino acids, respectively, with a molecular weight of 340,000.
- Fibrinogen can promote platelet aggregation, promote the growth, proliferation and contraction of smooth muscle and endothelial cells, increase blood viscosity and peripheral resistance, cause endothelial cell damage, promote collagen and DNA synthesis, and chemotactic mononuclear / macro Phage cells migrate under the intima to promote red blood cell adhesion and thrombosis. Therefore, it plays a very important role in the pathogenesis of cardiovascular disease.
- Clinical data show that: Most patients with elevated fibrinogen levels can suffer from myocardial infarction or sudden death, and the higher the fibrin level, the greater the risk; elevated plasma fibrinogen promotes the onset of atherosclerosis An important factor; fibrinogen rises, the blood is in a hypercoagulable state, the blood flow speed slows, blood viscosity increases, and thrombosis is easy to occur; hypertension is often accompanied by an increase in fibrinogen levels, which is induced and An important cause of aggravating hypertension; fibrinogen is closely related to fat metabolism; In addition, old age, smoking, obesity, stress, oral contraceptives and diabetes can promote fibrinogen levels in the body. [3]
Fibrinogen fibrinogen receptor antagonist
- Fibrinogen and platelet receptors are GPb / a. Fibrinogen receptor antagonists act on the final pathway of platelet aggregation, blocking the binding of fibrinogen to GPb / a receptors on platelets, inhibiting platelet aggregation, and extending The effect of clotting time and inhibition of thrombosis. [4]
- As shown
- Fibrinogen receptor antagonist
Fibrinogen fibrinolytic agent
- Fibrinolytic agents mainly inhibit the formation of thrombus in two aspects: On the one hand, it reduces the content of fibrinogen in the blood, inhibits platelet aggregation and adhesion, improves blood rheology, and inhibits the formation of thrombus. On the other hand, it breaks down fibrinogen, the decomposition products stimulate endothelial cells to secrete t-PA, activate the body's fibrinolytic system, and play a role in reducing fibrin content and thrombolysis. [4]