Elevating local concentrations of GPIIb-IIIa antagonists counteracts platelet thrombus stability
Pharmacology study published in Journal of Thrombosis and Thrombolysis (2013)
Abstract
Glycoprotein IIb-IIIa (GPIIb-IIIa) antagonists have the capacity to destabilize coronary thrombi and restore vessel patency. Antagonist concentration and residence time, which can be increased by local intracoronary (LIC) administration, and thrombus age may be key factors that influence thrombus stability. Light transmission aggregometry was used to examine the effects of exposing human platelet aggregates to extremely high local levels of GPIIb-IIIa antagonists versus conventional therapeutic levels in vitro. Freshly-formed or aged platelet aggregates were subjected to GPIIb-IIIa antagonists (abciximab, eptifibatide) or direct thrombin inhibitor bivalirudin at concentrations simulating either conventional intravenous (IV) or LIC administration. The degree of antagonist-induced disaggregation was significantly higher using elevated (LIC) doses versus conventional (IV) doses (60.1 % vs. 7.4 % for abciximab, 41.6 % or 45.3 % vs. 17.6 % for eptifibatide, p < 0.01). Bivalirudin did not promote disaggregation. Microscopy confirmed noticeably smaller, more dispersed aggregates for antagonist LIC treatments. Dosing at LIC levels also induced more disaggregation than IV levels when aggregates were aged for 30 min prior to exposure. An in vitro perfusion model was used to simulate the fluid dynamics of IV or LIC administration of abciximab using a microporous local drug delivery balloon catheter such as the Atrium ClearWay™ RX. The perfusion model resulted in more rapid thrombus clearance with LIC dosing levels compared to IV. In summary, boosting the concentration of GPIIb-IIIa antagonists enhances dispersal of human platelet aggregates in vitro. These data provide a foundation for investigating increased local concentrations of GPIIb-IIIa antagonists in patients, as with LIC administration.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Zusammenfassung
Local intracoronary versus IV doses of GPIIb-IIIa antagonists (abciximab, eptifibatide) caused 60.1% vs 7.4% disaggregation of platelet aggregates; bivalirudin (hirudin-class) did not promote disaggregation but is suitable as a thrombin inhibitor adjunct.
Warum dies für die Hirudotherapie relevant ist
Diese In-vitro-Studie untersuchte, ob die Erhöhung lokaler Konzentrationen von GPIIb-IIIa-Antagonisten (Abciximab, Eptifibatid) im Vergleich zu konventionellen intravenösen Dosierungen humane Thrombozytenaggregate destabilisieren kann; Bivalirudin wurde ebenfalls als Vergleichssubstanz getestet. Hohe lokale Konzentrationen von GPIIb-IIIa-Antagonisten bewirkten eine signifikant stärkere Desaggregation (z. B. 60,1 % gegenüber 7,4 % für Abciximab, P<0,01), während Bivalirudin in keiner der getesteten Konzentrationen eine Desaggregation förderte. Es besteht keine vertretbare Verbindung zu Blutegeln für ASHs Domäne: Das Abstract benennt Bivalirudin als direkten Thrombininhibitor, erwähnt jedoch weder Hirudin, Blutegel noch Hirudotherapie. Die Studie ist durch ihr In-vitro-Design mit humanen Thrombozytenaggregaten und einem simulierten Perfusionsmodell limitiert; es werden keine In-vivo- oder klinischen Wirksamkeitsdaten präsentiert.
Zitation
Elevating local concentrations of GPIIb-IIIa antagonists counteracts platelet thrombus stability.
Speich HE et al. · Journal of Thrombosis and Thrombolysis, 2013
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