Differential Inhibition of Human Atherosclerotic Plaque-Induced Platelet Activation by Dimeric GPVI-Fc and Anti-GPVI Antibodies Functional and Imaging Studies

Janina Jamasbi, Remco T. A. Megens, Mariaelvy Bianchini, Goetz Muench, Martin Ungerer, Alexander Faussner, Shachar Sherman, Adam Walker, Pankaj Goyal, Stephanie Jung, Richard Brandl, Christian Weber, Reinhard Lorenz, Richard Farndale, Natalie Elia, Wolfgang Siess*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

33 Citations (Web of Science)

Abstract

BACKGROUND Glycoprotein VI (GPVI) is the essential platelet collagen receptor in atherothrombosis, but its inhibition causes only a mild bleeding tendency. Thus, targeting this receptor has selective antithrombotic potential. OBJECTIVES This study sought to compare compounds interfering with platelet GPVI-atherosclerotic plaque interaction to improve current antiatherothrombotic therapy. METHODS Human atherosclerotic plaque-induced platelet aggregation was measured in anticoagulated blood under static and arterial flow conditions (550/s, 1,100/s, and 1,500/s). Inhibition by dimeric GPVI fragment crystallizable region of IgG (Fc) masking GPVI binding sites on collagen was compared with that of 3 anti-GPVI antibodies: BLO8-1, a human domain antibody; 5C4, a fragment antigen-binding (Fab fragment) of monoclonal rat immunoglobulin G; and m-Fab-F, a human recombinant sFab against GPVI dimers. RESULTS GPVI-Fc reduced plaque-triggered platelet aggregation in static blood by 51%, BLO8-1 by 88%, and 5C4 by 93%. Under arterial flow conditions, BLO8-1 and 5C4 almost completely inhibited platelet aggregation while preserving platelet adhesion on plaque. Inhibition by GPVI-Fc, even at high concentrations, was less marked but increased with shear rate. Advanced optical imaging revealed rapid persistent GPVI-Fc binding to collagen under low and high shear flow, upstream and downstream of plaque fragments. At low shear particularly, platelets adhered in plaque flow niches to GPVI-Fc-free segments of collagen fibers and recruited other platelets onto aggregates via ADP and TxA2 release. CONCLUSIONS Anti-GPVI antibodies inhibit atherosclerotic plaque-induced platelet aggregation under static and flow conditions more effectively than GPVI-Fc. However, potent platelet inhibition by GPVI-Fc at a higher shear rate (1,500/s) suggests localized antithrombotic efficacy at denuded or fissured stenotic high-risk lesions without systemic bleeding. The compound-specific differences have relevance for clinical trials targeting GPVI-collagen interaction combined with established antiplatelet therapies in patients with spontaneous plaque rupture or intervention-associated plaque injury.
Original languageEnglish
Pages (from-to)2404-2415
JournalJournal of the American College of Cardiology
Volume65
Issue number22
DOIs
Publication statusPublished - 9 Jun 2015

Keywords

  • antithrombotic
  • atherothrombosis
  • glycoprotein VI
  • plaque rupture

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