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Thromb Haemost 2018; 118(01): 090-102
DOI: 10.1160/TH17-05-0330
Coagulation and Fibrinolysis
Schattauer GmbH Stuttgart

Passivating Injured Endothelium with Kinexins in Thrombolytic Therapy

Yunn-Hwa Ma
,
Chao-Wei Huang
,
Chih-Jen Wen
,
Yi-Ching Lu
,
Shiaw-Pyng Wey
,
Tze-Chein Wun
Further Information

Publication History

15 May 2017

10 October 2017

Publication Date:
05 January 2018 (online)

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Abstract

Without conjunctive administration of an anticoagulant, endothelial injury-induced thrombosis is resistant to thrombolysis and prone to re-thrombosis. We hypothesized that co-delivery of recombinant tissue plasminogen activator (rtPA) with annexin V–containing anticoagulants that specifically target the injured endothelium may passivate the thrombogenic elements of the vascular injury site and enhance rtPA-induced thrombolysis. In this study, the effects of conjunctive administration of Kinexins (Kunitz inhibitor–annexin V fusion proteins) with rtPA on thrombolysis were determined in vitro and in vivo. Thromboelastometry showed that both TAP-A (tick anticoagulant peptide–annexin V fusion protein; an inhibitor of factor Xa [FXa] and prothrombinase) and A-6L15 (annexin V-6L15 fusion protein; an inhibitor of tissue factor/FVIIa) exerted concentration-dependent (10–100 nM) effects on clot formation, with TAP-A being several folds more potent than A-6L15 in whole blood. Combination of TAP-A or A-6L15 with rtPA (1 μg/mL) led to decrease in lysis index, suggesting conjunctive enhancement of thrombolysis by combined use of rtPA with TAP-A or A-6L15. In a rat cremaster muscle preparation subjected to photochemical injury, conjunctive administration of rtPA and TAP-A significantly restored tissue perfusion to 56%, which is approximately two fold of that by rtPA or TAP-A alone. Near-infrared fluorescence images demonstrated local retention of a fluorescent A-6L15-S288 at the injury site, suggesting a targeting effect of the fusion protein. Pharmacokinetic analysis showed that 123I-labelled TAP-A and A-6L15 had initial distribution half-lives (T1/2α) of approximately 6 minutes and elimination half-lives (T1/2β) of approximately 2.3 hours. In conclusion, Kinexins were potentially useful adjunctive agents with rtPA thrombolytic therapy especially for thrombosis induced by endothelial injury.

Keywords

plasminogen activators - thrombolysis - annexin V - kunitz protease inhibitor - anticoagulants

Author Contributions

Y.-H.M. is responsible for the experimental design, writing and funding of the work; C.-W.H. conducted most of the experiments and analysis in this study as his master's thesis; C.-J.W. contributed to verifying the targeting effects of A-6L15; Y.-C.L. designed and conducted the pharmacokinetic study; S.-P.W. designed and supervised all studies involving radioactive materials; T.-C.W. synthesized Kinexins and actively participated in discussion and writing of this work.


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