title: Antibody-based prevention of von Willebrand factor degradation mediated by circulatory assist devices.
abstract: Haemorrhagic episodes in patients carrying circulatory assist devices represent a severe life-threatening clinical complication. These bleeding episodes may originate from a reduced functionality of von Willebrand factor (VWF), a multimeric protein pertinent to the formation of a haemostatic plug. It has been reported that the reduced functionality is due to increased proteolytic degradation by the enzyme ADAMTS13, a phenomenon that is facilitated by device-induced increases in shear stress to which VWF is exposed. Here, we have tested a series of VWF-derived protein fragments and monoclonal murine anti-VWF antibodies for their capacity to reduce shear stress-dependent degradation of VWF. Via direct binding experiments, we identified an anti-VWF antibody that partially blocked VWF-ADAMTS13 interactions (46 ± 14%). Epitope mapping experiments revealed that the antibody, designated mAb508, is directed against the distal portion of the VWF D4-domain (residues 2134-2301) and recognises a synthetic peptide encompassing residues 2158-2169. Consistent with its partial inhibition of VWF-ADAMTS13 interactions in binding assays, mAb508 reduced ADAMTS13-mediated VWF degradation in a vortex-based degradation assay by 48 ± 10%. In a HeartMateII-based whole blood-perfusion system, mAb508 was able to reduce degradation of high-molecular-weight (HMW)-VWF-multimers dose-dependently, with a maximal inhibition (83 ± 8%) being reached at concentrations of 10 μg/ml or higher. In conclusion, we report that partial inhibition of VWF-ADAMTS13 interactions using an anti-VWF antibody can prevent excessive degradation of HMW-VWF multimers. This strategy may be used for the development of therapeutic options to treat bleeding episodes due to shear stress-dependent VWF degradation, for instance in patients carrying circulatory assist devices.
authors.forename: Antoine
authors.initials: A
authors.lastname: Rauch
authors.forename: Paulette
authors.initials: P
authors.lastname: Legendre
authors.forename: Olivier D
authors.initials: OD
authors.lastname: Christophe
authors.forename: Jenny
authors.initials: J
authors.lastname: Goudemand
authors.forename: Eric
authors.initials: E
authors.lastname: van Belle
authors.forename: André
authors.initials: A
authors.lastname: Vincentelli
authors.forename: Cécile V
authors.initials: CV
authors.lastname: Denis
authors.forename: Sophie
authors.initials: S
authors.lastname: Susen
authors.affiliation: Peter J. Lenting, INSERM U770, 80 rue du General Leclerc, 94276 Le Kremlin-Bicêtre, France, Tel.: +33 149595651, Fax: +33 146719472, E-mail: peter.lenting@inserm.fr.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Lenting
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism*; D000071120:ADAMTS13 Protein; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D000937:Antigen-Antibody Reactions; D004306:Dose-Response Relationship, Immunologic; D000939:Epitopes / Q000276:immunology; D006353:Heart-Assist Devices / Q000009:adverse effects*; D018056:Hemorheology; D006470:Hemorrhage / Q000097:blood / Q000209:etiology / Q000517:prevention & control*; D006487:Hemostasis; D006801:Humans; D051379:Mice; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000276:immunology; D017434:Protein Structure, Tertiary; D059748:Proteolysis; D011994:Recombinant Proteins / Q000378:metabolism; D014841:von Willebrand Factor / Q000276:immunology / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D010446:Peptide Fragments; D011994:Recombinant Proteins; D014841:von Willebrand Factor; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human
keywords: ADAMTS13; acquired von Willebrand syndrome; antibody therapy; circulatory assist devices; von Willebrand factor