T. A. Yatsenko, V. М. Rybachuk, O. I. Yusova, S. M. Kharchenko, T. V. Grinenko

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: topolius@yandex.ua

Fibrin clot lysis by plasminogen/plasmin system results in fibrin degradation products formation with subsequent release into bloodstream. The fragments contain specific binding sites for fibrinolytic system components and can interact with them. In this study, we investigated the way in which fibrin fragments effect fibrinolytic process. We have shown that high molecular weight products of fibrin degradation and fibrin fragments of DDE-complex and DD, but not end product Е₃, stimulate plasmin formation. Additionally, components of DDE-complex mixture of fragments Е₁ and Е₂ have potentiation ability. The intermediate fibrin fragments hmFDPs and DDE attenuate clot lysis by plasmin and hmFDPs protect plasmin from α₂-antiplasmin inhibition but under further fragmentation to endpoint fibrin fragments loose this ability. The plasma inhibitors reduce fibrinolytic system activity generated by the degradation products. Thus, fibrin fragments formed during the clot lysis can bind and move out fibrinolytic system components from clot volume and in this way result in clot resistance to hydrolysis.

Keywords: activation, fibrin degradation products, plasmin inhibition, plasminogen, potentiation effect, t-PA