Additive effect of the combined administration of low molecular weight heparin and recombinant hirudin on thrombus growth in a rabbit jugular vein thrombosis model
Research article published in Thrombosis and haemostasis (1994)
Abstract
Recombinant hirudin (r-hirudin) is a new anticoagulant with specific antithrombin activity independently of antithrombin III. Low molecular weight heparins (LMWH) exert predominantly anti-Xa activity. Therefore, we hypothesized that combined administration of r-hirudin and LMWH would induce a stronger antithrombotic effect as compared to r-hirudin administered alone or combined with unfractionated heparin. To assess the effect on thrombus growth, we determined the accretion of 125I-labeled fibrinogen onto autologous non-radioactive thrombi preformed in the jugular veins of rabbits. The rabbits received unfractionated heparin (80 anti-factor Xa U), LMWH (80 anti-factor Xa U) or r-hirudin (0.3, 5.0 and 10.0 mg/kg) either separately or by combined infusion for a 3 h period. R-Hirudin reduced the thrombus growth in a dose dependent fashion. The combined administration of 80 anti-Xa U LMWH and r-hirudin at a dose of 0.3 mg/kg resulted in a stronger antithrombotic effect as compared to the combined infusion of unfractionated heparin and r-Hirudin (thrombus growth: 14.3% +/- 6.0 vs 28.9% +/- 6.5; p = 0.001). This difference in additive antithrombotic effect of 80 anti-Xa U LMWH versus unfractionated heparin on r-hirudin was also observed when LMWH was combined with 5.0 mg/kg and 10.0 mg/kg r-hirudin versus unfractionated heparin combined with r-hirudin (thrombus growth: 16.4% +/- 1.6 vs 29.1% +/- 3.9; p = 0.01 and 10.1% +/- 1.8 vs 20.4% +/- 4.5; p = 0.001, respectively). In conclusion, this study showed an additive antithrombotic effect of LMWH on the thrombus growth reducing effect of r-hirudin.(ABSTRACT TRUNCATED AT 250 WORDS)
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Peer-reviewed research on leech salivary pharmacology and bioactive peptides relevant to anticoagulation. Indexed in PubMed and verified against the NCBI record.
Why This Matters for Hirudotherapy
This preclinical animal study tested whether combining recombinant hirudin with low-molecular-weight heparin (LMWH) produces a stronger antithrombotic effect than hirudin alone or with unfractionated heparin, using radiolabeled-fibrinogen accretion onto preformed thrombi in a rabbit jugular-vein model; the abstract reports that r-hirudin reduced thrombus growth dose-dependently and that adding LMWH gave a significantly greater antithrombotic effect than adding unfractionated heparin (e.g., 14.3% vs 28.9% thrombus growth at 0.3 mg/kg, p=0.001). This is squarely on the medicinal-leech secretome story: hirudin is the leech's prototypical antithrombin-III-independent thrombin inhibitor, and the study probes how this leech-derived molecule behaves in combination anticoagulation. Caveat: this is an acute rabbit model, not a clinical trial — preclinical animal results do not establish safety, dosing, or efficacy in humans, and the abstract was truncated at 250 words, so the full conclusions are not captured here.
Citation
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