Summary
The structure of the fibrin network, the hemodynamic environment of the clot, the
kinetic properties of the fibrinolytic enzymes and the balance of their formation
and inactivation essentially determine the effectiveness of fibrinolysis in vivo. The fibrin structure and the action of proteases, however depend considerably on
additional, apparently inert physiological and pathological factors, which are restricted
to more or less transient compartments in fluid-solid interface, such as thrombus
(fibrin with platelet membrane structures), endothelial cell surface, the environment
of polymorphonuclear cells (PMN). In these compartments extreme changes in concentrations
and rate enhancements are observed. Components released by endothelial cells, PMNs
and platelets or molecules present in circulating blood create a heterogeneous milieu
that modulates fibrinolysis. This review summarizes the effects, and where it is possible,
explains the mechanism of modulators of the fibrinolytic processes, such as cell membrane
and cellular contents of endothelium, PMN and platelets present in thrombi, the action
of normal and pathological blood plasma- and extracellular matrix-components.
Keywords
Compartmental fibrinolysis - fibrin degradation - plasminogen activation - tPA-cofactors
- endothelial cells - polymorphonuclear cells
