Pyrogova L. V. Formation and hydrolysis of the fibrin clot in blood plasma at pathological conditions and under the action of exogenous factors. – Manuscript.
Thesis for the PhD degree in the biological sciences for specialty 03.00.20 – biotechnology. - Palladin Institute of biochemistry of the National Academy of Sciences of Ukraine, Kyiv, 2020.
The research is dedicated to the development of a method of the haemostasis system analysis that would allow to determine the level of activation, interaction and interconnection of the system’s components in the process of formation and hydrolysis of the fibrin clot in human blood plasma under certain pathologies associated with haemostasis disregulation and under the action of antithrombotic agents.
The study was performed in blood plasma of donors and patients which had myocardial infarction, stroke, aortic stenosis, stenocardia, chronic renal disease and hip replacement therapy, analyzed in two experimental setups. The first one targeted the process of formation and hydrolysis of the fibrin clot. The process was initiated by the APTT reagent which activates the intrinsic pathway of blood clotting cascade and is characterized by the parameters of the haemostatic potential (clotting potential (CP), fibrinolytic potential (FP) and overall hemostatic potential (OHP)) and certain segments of the turbidity curve (τ – lag-period, V1 – speed of lateral protofibril association, H – maximum turbidity of clot, L – half-lysis time, V2 – clot hydrolysis speed). The second setup included evaluating the haemostasis system by such molecular markers as fibrinogen, soluble fibrin, protein C and D-dimer at the time of blood collection.
The ratio of the clotting potential to fibrinolytic potential (CT/FP) was found to be an important marker of the balance between the coagulation and fibrinolysis and an important parameter of the overall direction of change in the patient’s haemostasis.
Comparative analysis of the values of the haemostatic potential, turbidity curve and concentrations of molecular markers showed that the activity of the haemostasis system in women with chronic renal disease is higher than in men. In patients with chronic renal disease, protein C concentration became highly anti-correlated with fibrinogen (-0,73), clotting potential (-0,81) and fibrinolytic potential (-0,93). This suggests the existence of strong correlational links binding together the clotting cascade, fibrinolysis and the anticoagulant system of protein C and is a promising target of developing prognostic methods to evaluate haemostasis.
Soluble fibrin was found to be only weakly correlated with D-dimer and not its direct antecedent. We offer a hypothesis about the formation of fibrin microclots in blood plasma as a necessary intermediate chain for the activation of fibrinolytic system and the formation of D-dimer.
Application of the improved method of hemostatic potential to the analysis of anticlotting agents’ effect on the donors’ hemostatic system allowed us to establish that calix[4]arene C-145 inhibited the formation of the fibrin clot without unsettling the dynamic balance of the coagulational and fibrinolytic parts of the haemostasis. Also, heparine was shown to change the fibrin clot’s structure in plasma, thus accelerating fibrinolysis
Key words: fibrinogen, fibrin polimerization, total haemostatic potential, soluble fibrin, D-dimer, protein C.
