Differential antiplatelet efficacy for various GPIIb/IIIa antagonists: Role of plasma calcium levels

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• 作者：Mousa ; Shaker A. ; Bozarth ; Jeffrey M. ; Forsythe ; Mark S. ; Slee ; Andrew
• 关键词：GPIIb/IIIa ; Glycoprotein IIb/IIIa ; PRP ; platelet-rich plasma ; PPP ; platelet poor plasma ; Ca⁺⁺ ; Calcium ; ADP ; Adenosine diphosphate ; TRAP ; PRP ; Thrombin receptor activating peptide ; obtained from citrated blood ; cPRP ; PRP ; obtained from heparini
• 刊名：Cardiovascular Research
• 出版年：2000
• 出版时间：September, 2000
• 年：2000
• 卷：47
• 期：4
• 页码：819-826
• 全文大小：519 K

文摘

Objectives: The present study was undertaken to determine the effects of free ionized calcium influenced by either the anticoagulant used (citrate vs. heparin) or directly varying the calcium levels after treatment of blood with citrate on the antiplatelet efficacy of two classes of GPIIb/IIIa antagonists. Methods: The platelet effects of changes in plasma [Ca⁺⁺] with the different GPIIb/IIIa antagonists were determined using light transmittance aggregometry, direct binding kinetics, and ¹²⁵I-fibrinogen binding to activated human platelets. Results: A significantly higher IC50s was shown with heparin (free ionized calcium=1.1 mM) as compared to that with citrate (free ionized calcium=0.12 mM) with class II GPIIb/IIIa antagonists (P<0.01) such as Orbofiban, and Integrilin. In contrast, class I GPIIb/IIIa antagonists such as Roxifiban and Abciximab showed no significant changes in their IC50s in either citrate or heparin. Similar data were shown with other non-calcium chelating anticoagulant such as PPACK as compared to that with heparin. Additionally, similar data were shown with regard to the [Ca⁺⁺] sensitivity for GPIIb/IIIa antagonists from Class II but not Class I in the changes in IC50 values required for the inhibition of ¹²⁵I-fibrinogen binding to activated human gel filtered platelets. Additionally, examples from Class I GPIIb/IIIa antagonists such as ³H-active form of Roxifiban showed no significant changes in its platelet binding affinity in response to change in [Ca⁺⁺]. In contrast, GPIIb/IIIa antagonists from class II such as ³H-active form of Orbofiban demonstrated significant changes (P<0.01) in its platelet binding kinetics and antiplatelet efficacy in response to changes in Ca⁺⁺ concentrations. Conclusions: These data suggest the impact of the method of blood collection or changes in plasma calcium levels on the antiplatelet efficacy for class II but not class I GPIIb/IIIa antagonists depending on their platelet binding kinetics.