Causes of abnormalities in the plasmin system

Under the influence of various pathological processes, the state of the plasmin system and the production of its individual components change. As a result of activation of the plasmin system, hemostasis is disrupted and hemorrhagic fibrinolytic syndrome develops quite often. Clinically, it is manifested by severe bleeding due to multiple defects in the hemostasis system. This syndrome can be latent: bleeding is observed in patients only in the postoperative and postpartum periods with tissue damage. Most often, such conditions are detected in patients with liver damage as a result of decreased synthesis of antiplasmins, with damage to organs rich in plasminogen activators, and during surgical interventions on them (during operations for prostate cancer, lung cancer), less often - in patients with increased production (drug, bacterial, stress, etc.) of plasminogen activators or their increased concentration. Such fibrinolysis, caused by the primary activation of the plasmin system as such and not reflecting the body's reaction to the increase in fibrin formation, is primary fibrinolysis. To correct it, antifibrinolytic drugs of the antiprotease type (aprotinin, ε-aminocaproic acid) are prescribed.

In most cases, secondary fibrinolysis is observed due to activation of the plasmin system to form fibrin in the body. In secondary fibrinolysis, plasmin activity initially increases, then gradually decreases, and finally disappears completely due to the depletion of plasminogen reserves. Often, the concentration of plasminogen activators also decreases against the background of a reduced or increased amount of antiplasmins. The ability of a number of drugs to convert inactive plasminogen into plasmin is the basis for thrombolytic therapy in patients with myocardial infarction and thromboembolism - by administering plasminogen activators (most often streptokinase drugs). When conducting thrombolytic therapy, constant monitoring of the plasminogen level in the blood is necessary.

Changes in the hemostasis system during primary and secondary fibrinolysis

Indicators	Fibrinolysis
	Primary	Secondary
Fibrinogen	Reduced	Reduced
Plasminogen	Increased	Reduced
A 2 -AP	Reduced	Increased
PDF	Increased	Increased

The most obvious shifts in the plasmin system are observed in DIC syndrome, when at first the activation of fibrinolysis is a protective, sanogenic reaction, and therefore plasmin inhibitors are contraindicated here.

It should be borne in mind that plasminogen, like all other acute phase proteins, increases during infections, injuries, tumors and in the last months of pregnancy.