RGD Reference Report - In vitro and in vivo characterisation of the profibrinolytic effect of an inhibitory anti-rat TAFI nanobody. - Rat Genome Database

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In vitro and in vivo characterisation of the profibrinolytic effect of an inhibitory anti-rat TAFI nanobody.

Authors: Hendrickx, ML  Zatloukalova, M  Hassanzadeh-Ghassabeh, G  Muyldermans, S  Gils, A  Declerck, PJ 
Citation: Hendrickx ML, etal., Thromb Haemost. 2014 May 5;111(5):824-32. doi: 10.1160/TH13-08-0645. Epub 2014 Jan 9.
RGD ID: 11341738
Pubmed: (View Article at PubMed) PMID:24402608
DOI: Full-text: DOI:10.1160/TH13-08-0645

One of the main disadvantages of current t-PA thrombolytic treatment is the increased bleeding risk. Upon activation, thrombin activatable fibrinolysis inhibitor (TAFI) is a very powerful antifibrinolytic enzyme. Therefore, co-administration of a TAFI inhibitor during thrombolysis could reduce the required t-PA dose without compromising the thrombolytic efficacy. In this study we generated and characterised a nanobody that is inhibitory towards rat TAFI and evaluated its profibrinolytic property in vitro and in vivo. Nanobody VHH-rTAFI-i81 inhibits (at a 16-fold molar ratio nanobody over TAFI) the thrombin/thrombomodulin (T/TM)-mediated activation of rat TAFI (rTAFI) by 83 +/- 1.8% with an IC50 of 0.46 (molar ratio nanobody over TAFI). The affinity (KA) of VHH-rTAFI-i81 for rTAFI, as determined by surface plasmon resonance (Biacore(R)), is 2.5 +/- 0.2 x 10(10) M(-1) and illustrates a very strong binding. In an in vitro clot lysis assay, administration of VHH-rTAFI-i81 strongly enhances the degree of lysis and reduces time to reach full lysis of t-PA-mediated clot lysis. Epitope mapping discloses that Lys392 is of primary importance for the nanobody/rTAFI interaction besides minor contributions of Tyr175 and Glu183. In vivo application of VHH-rTAFI-i81 in a tissue factor-induced mouse thromboembolism model significantly decreases fibrin deposition in the lungs in the absence of exogenous administered t-PA. Nanobody VHH-rTAFI-i81 is a very potent inhibitor of T/TM-mediated TAFI activation. Co-administration of this nanobody and t-PA enhances the fibrinolytic efficacy. In an in vivo mouse thromboembolism model, VHH-rTAFI-i81 reduces fibrin deposition in the lungs.

Disease Annotations    
Thromboembolism  (IDA,ISO)

Objects Annotated

Genes (Rattus norvegicus)
F3  (coagulation factor III, tissue factor)

Genes (Mus musculus)
F3  (coagulation factor III)

Genes (Homo sapiens)
F3  (coagulation factor III, tissue factor)

Additional Information