Takahashi H, Kashima T, Nomoto S, Iwade K, Tainaka H, Shimizu T, Nomizo Y, Muramoto N, Kimura S, Echizen H
Department of Pharmacotherapy, Meiji Pharmaceutical University, Kiyare, Tokyo, Japan.
Pharmacogenetics. 1998 Oct;8(5):365-73. doi: 10.1097/00008571-199810000-00001.
To study whether an in-vitro model for three different genotypes of human CYP2C93 polymorphism would be useful for predicting the in-vivo kinetics of (S)-warfarin in patients with the corresponding genotypes, the intrinsic clearance (Cl(int) or Vmax/Km) for (S)-warfarin 7-hydroxylation obtained from recombinant human CYP2C91 [wild-type (wt)] and CYP2C93 (Leu359/Leu) expressed in yeast and the mixture of equal amounts of these were compared with the in-vivo unbound oral CI (CI(po,u)) of (S)-warfarin obtained from 47 Japanese cardiac patients with the corresponding CYP2C9 genotypes. The in-vitro study revealed that the recombinant CYP2C91 (wt/wt), 2C93 (Leu359/Leu) and their mixture (Ile359/Leu) possessed a mean Km of 2.6, 10.4 and 6.6 microM and Vmax of 280, 67 and 246 pmol/min/nmol P450, respectively. Thus, the mean in-vitro Cl(int) obtained from recombinant CYP2C93 (Leu359/Leu) and the mixture (Ile359/Leu) of 2C93 and 2C91 were 94% and 65% lower than that obtained from CYP2C91 (wt/wt) (6.7 versus 38 versus 108 ml/min/micromol P450, respectively). The in-vivo study showed that the median Cl(po,u) for (S)-warfarin obtained from patients with homozygous (Leu359/Leu, n = 1) and heterozygous (Ile359/Leu, n = 4) CYP2C93 mutations were reduced by 90% (62 ml/min) and 66% (212 ml/min, P < 0.05) compared with that obtained from those with homozygous 2C91 (625 ml/min, n = 42). Consequently, there was a significant correlation (r = 0.99, P < 0.05) between the in-vitro Cl(int) for (S)-warfarin 7-hydroxylation and the in-vivo Cl(po,u) for (S)-warfarin in relation to the CYP2C93 polymorphism. In conclusion, the in-vitro model for human CYP2C93 polymorphism using recombinant cytochrome P450 proteins would serve as a useful means for predicting changes in in-vivo kinetics for (S)-warfarin and possibly other CYP2C9 substrates in relation to CYP2C93 polymorphism.
为研究针对人类CYP2C93三种不同基因型多态性的体外模型是否有助于预测相应基因型患者体内（S）-华法林的动力学，将重组人CYP2C91[野生型（wt）]和CYP2C93（Leu359/Leu）在酵母中表达以及等量混合物中获得的（S）-华法林7-羟化的内在清除率（Cl(int)或Vmax/Km）与47例具有相应CYP2C9基因型的日本心脏病患者体内（S）-华法林的未结合口服清除率（Cl(po,u)）进行比较。体外研究显示，重组CYP2C91（wt/wt）、2C93（Leu359/Leu）及其混合物（Ile359/Leu）的平均Km分别为2.6、10.4和6.6 microM，Vmax分别为280、67和246 pmol/min/nmol P450。因此，从重组CYP2C93（Leu359/Leu）以及2C93和2C91的混合物（Ile359/Leu）获得的平均体外Cl(int)分别比从CYP2C91（wt/wt）获得的低94%和65%（分别为6.7对38对108 ml/min/微摩尔P450）。体内研究表明，与纯合2C91患者（625 ml/min，n = 42）相比，纯合（Leu359/Leu, n = 1）和杂合（Ile359/Leu, n = 4）CYP2C93突变患者体内（S）-华法林的Cl(po,u)中位数分别降低了90%（62 ml/min）和66%（212 ml/min，P < 0.05）。因此，（S）-华法林7-羟化的体外Cl(int)与（S）-华法林的体内Cl(po,u)之间在CYP2C93多态性方面存在显著相关性（r = 0.99，P < 0.05）。总之，使用重组细胞色素P450蛋白的人类CYP2C93多态性体外模型将成为预测（S）-华法林以及可能其他CYP2C9底物在CYP2C93多态性方面体内动力学变化的有用手段。
