Tridegin, a novel peptidic inhibitor of factor XIIIa from the leech, Haementeria ghilianii, enhances fibrinolysis in vitro
Research article published in Thrombosis and haemostasis (1997)
Abstract
Tridegin is a potent inhibitor of factor XIIIa 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.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Peer-reviewed clinical and outcomes research relevant to medicinal leech therapy and its biology. Indexed in PubMed and verified against the NCBI record.
Why This Matters for Hirudotherapy
This in vitro study characterized tridegin, a small peptide factor XIIIa inhibitor from the leech Haementeria ghilianii, showing it blocks protein cross-linking, abolishes D-dimer formation, roughly halves fibrinolysis time, and restores fibrinolytic sensitivity in platelet-rich plasma clots, leading the authors to suggest it may have potential as an adjunct to thrombolytic therapy. This is a foundational entry in the leech-secretome drug-discovery story: it isolates a discrete leech-derived molecule with a defined mechanism (anti-cross-linking, profibrinolytic) distinct from the better-known antithrombin hirudin, illustrating the pharmacological diversity ASH cites as the scientific basis for medicinal-leech interest. The caveat is firm: these are 1997 in vitro plasma-clot experiments only, with no animal or human data, so the suggested thrombolytic-adjunct role remains an early-stage hypothesis, not a clinical finding.
Citation
Added to ASH library: May 28, 2026 · Site last updated: June 18, 2026