Improving long circulation and procoagulant platelet targeting by engineering of hirudin prodrug
Research article published in International journal of pharmaceutics (2020)
Abstract
To reduce systemic bleeding risks during anticoagulant treatment, a new concept named "precise anticoagulation" was proposed to localize the effects of anticoagulants via the targeted delivery of prodrugs to the coagulation site. In this study, the fusion protein Annexin V-hirudin 3-ABD (hAvHA) was constructed to achieve the prolonged circulation and targeted delivery of hirudin to coagulation sites. hAvHA was inactive as a prodrug, and it could bind to albumin during circulation. The drug was quickly activated via factor Xa-mediated cleavage once coagulation occurred, and hirudin was efficiently released to exert antithrombin activity in vitro. The hAvHA protein could be activated in mouse blood and exert significant anticoagulation effects. The results of FITC labeling illustrated that hAvHA bound to procoagulant platelets, suggesting the Annexin V modification permits targeted delivery to sites of thrombosis. hAvHA bound to albumin in vitro with an equilibrium dissociation constant of 8 pM, suggesting the ABD modification permitted prolonged circulation in vivo. Moreover, the bleeding time was much shorter in hAvHA-treated mice than in hirudin-treated mice. Therefore, our results suggested that that hAvHA is a potential and promising anticoagulant in vivo.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Improving long circulation and procoagulant platelet targeting by engineering of hirudin prodrug.
Why This Matters for Hirudotherapy
This study constructed a fusion protein, Annexin V-hirudin 3-ABD (hAvHA), as a prodrug designed to localize hirudin's anticoagulant activity to thrombosis sites. The prodrug binds albumin for prolonged circulation, is activated by factor Xa-mediated cleavage at coagulation sites, and releases hirudin to inhibit thrombin; in mice, hAvHA produced significant anticoagulation with shorter bleeding times than free hirudin. This is relevant to ASH because it engineers hirudin—the signature leech anticoagulant—into a targeted therapeutic with potentially improved safety. Caveat: the work is preclinical (in vitro and mouse models) and does not involve live leeches or hirudotherapy.
Citation
Improving long circulation and procoagulant platelet targeting by engineering of hirudin prodrug
Han H et al. · International journal of pharmaceutics, 2020
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