Identification of the Human Cytochrome P450 Enzymes Involved in the Two Oxidative Steps in the Bioactivation of Clopidogrel to Its Pharmacologically Active Metabolite
作者:Miho Kazui、Yumi Nishiya、Tomoko Ishizuka、Katsunobu Hagihara、Nagy A. Farid、Osamu Okazaki、Toshihiko Ikeda、Atsushi Kurihara
DOI:10.1124/dmd.109.029132
日期:2010.1
The aim of the current study is to identify the human cytochrome P450 (P450) isoforms involved in the two oxidative steps in the bioactivation of clopidogrel to its pharmacologically active metabolite. In the in vitro experiments using cDNA-expressed human P450 isoforms, clopidogrel was metabolized to 2-oxo-clopidogrel, the immediate precursor of its pharmacologically active metabolite. CYP1A2, CYP2B6, and CYP2C19 catalyzed this reaction. In the same system using 2-oxo-clopidogrel as the substrate, detection of the active metabolite of clopidogrel required the addition of glutathione to the system. CYP2B6, CYP2C9, CYP2C19, and CYP3A4 contributed to the production of the active metabolite. Secondly, the contribution of each P450 involved in both oxidative steps was estimated by using enzyme kinetic parameters. The contribution of CYP1A2, CYP2B6, and CYP2C19 to the formation of 2-oxo-clopidogrel was 35.8, 19.4, and 44.9%, respectively. The contribution of CYP2B6, CYP2C9, CYP2C19, and CYP3A4 to the formation of the active metabolite was 32.9, 6.76, 20.6, and 39.8%, respectively. In the inhibition studies with antibodies and selective chemical inhibitors to P450s, the outcomes obtained by inhibition studies were consistent with the results of P450 contributions in each oxidative step. These studies showed that CYP2C19 contributed substantially to both oxidative steps required in the formation of clopidogrel active metabolite and that CYP3A4 contributed substantially to the second oxidative step. These results help explain the role of genetic polymorphism of CYP2C19 and also the effect of potent CYP3A inhibitors on the pharmacokinetics and pharmacodynamics of clopidogrel in humans and on clinical outcomes.
本研究旨在确定参与
氯吡格雷生物活化为其药理活性代谢物的两个
氧化步骤的人类细胞色素 P450(P450)同工酶。在使用 cDNA 表达的人类 P450 同工酶进行的体外实验中,
氯吡格雷被代谢为 2-
氧代
氯吡格雷,即其药理活性代谢物的直接前体。CYP1A2、CYP2B6 和 CYP2C19 催化了这一反应。在以 2-oxo-clopidogrel 为底物的同一系统中,检测
氯吡格雷的活性代谢物需要在系统中添加
谷胱甘肽。CYP2B6、CYP2C9、CYP2C19 和 CYP3A4 对活性代谢物的产生做出了贡献。其次,利用酶动力学参数估算了参与两个
氧化步骤的每个 P450 的贡献。CYP1A2、CYP2B6和CYP2C19对2-
氧代
氯吡格雷形成的贡献率分别为35.8%、19.4%和44.9%。CYP2B6、CYP2C9、CYP2C19 和 CYP3A4 对活性代谢物形成的贡献率分别为 32.9%、6.76%、20.6% 和 39.8%。在使用 P450s
抗体和选择性
化学抑制剂进行的抑制研究中,抑制研究得出的结果与 P450 在每个
氧化步骤中的贡献结果一致。这些研究表明,CYP2C19 对形成
氯吡格雷活性代谢物所需的两个
氧化步骤都有很大贡献,而 CYP3A4 则对第二个
氧化步骤有很大贡献。这些结果有助于解释 CYP2C19
基因多态性的作用,以及强效 CYP3A
抑制剂对
氯吡格雷人体药代动力学和药效学以及临床结果的影响。