Summary
Tridegin is a potent inhibitor of factor Xllla from the leech, Haementeria ghilianii, which inhibits protein cross-linking. It modifies plasmin-mediated fibrin degradation
as shown by the absence of D-dimer and approximately halves the time for fibrinolysis.
Plasma clots formed in the presence of Tridegin lyse more rapidly when either streptokinase,
tissue plasminogen activator or hementin is added 2 h after clot formation. The effect
of Tridegin is markedly increased if clots are formed from platelet-rich plasma. Platelet-rich
plasma clots are lysed much more slowly by the fibrinolytic enzymes used and if Tridegin
is present, the rate of lysis returns almost to that of platelet- free clots. These
studies indicate the important role of platelets in conferring resistance to commonly
used fibrinolytic enzymes and suggest that protein cross-linking is an important step
in this effect. Moreover they indicate that Tridegin, a small polypeptide, may have
potential as an adjunct to thrombolytic therapy.
