细胞色素P450 2C9第4外显子及-65G/C多态性与华法林敏感性关系研究

Association of polymorphisms of cytochrome P450 2C9 exon 4 and - 65G ＞ C with warfarin sensitivity

目的 探讨中国人群细胞色素P450 2C9（cytochrome P450 2C9,CYP2C9）第4外显子608T/G,561A/C,537A/C,527A/C及其上游65位G/C多态性位点与华法林敏感性关系.方法 接受华法林抗凝治疗患者共102例.遵医嘱口服一定剂量的华法林,合理饮食并坚持随访.随访期间记录患者华法林剂量水平及每次复查国际标准化比值（international normalized ratio,INR）数值,同时记录用药期间出血或栓塞等不良事件发生情况.获取患者血液标本并提取DNA,采用PCR扩增包括CYP2C9第4外显子608T/G、561A/C、537A/C、527A/C及其上游65位G/C的基因片段.测序后对上述基因多态性位点进行对比分析.结果 抗凝治疗过程中以维持凝血酶原时间国际标准化比值（prothrombin time-INR,PT-INR）1.5～2.5为达标范围,华法林维持剂量为1.250～5.077 mg/d,平均（2.609±0.716）mg/d.基因测序结果显示本研究人群中未发现CYP2C9第4外显子存在多态性位点.CYP2C9第4外显子-65GC基因型患者服用华法令维持剂量较GG基因型显著增高[（3.106±0.619）mg/d vs（2.555±0.708）mg/d,P＜0.05].华法林维持剂量大于2.5 mg/d,对于预测CYP2C9第4外显子-65GC基因型携带者有较高价值（曲线下面积：0.770,P=0.005,95%CI：0.626～0.915）.Logistic回归分析显示,本研究人群中,仅体重指数成为治疗期间出血的独立危险因素（OR=0.794,95%CI：0.651～0.970,P=0.024）,CYP2C9第4外显子-65GC基因型以及性别、年龄、口服降糖药等与出血风险之间危险因素分析无统计学意义.结论 研究人群对华法林普遍敏感.研究对象中CYP2C9第4外显子的基因序列高度保守.CYP2C9第4外显子-65GC基因携带者华法林平均维持剂量经统计学分析显著高于非携带者,其临床意义仍需通过更多大规模多中心临床研究作进一步验证.

Objective To investigate the association of the polymorphisms of cytochrome P450 2C9（ CYP2C9 ） exon 4 608T/G, 561A/C, 537A/C and 527A/C, and - 65G/C with warfarin sensitivity.Methods A total of 102 patients under warfarin anticoagulant therapy were selected. During follow-up,warfarin dosage and associated Prothrombin Time-International Normalized Ratio （PT-INR） values were recorded. Simultaneous monitoring of incidence of bleeding and thrombosis adverse effect was recommended. Genetic polymorphisms of the above mentioned loci were identified by polymerase chain reaction and DNA sequencing. Results The average age of the 102 patients was （62.1 ± 10.5） years. The body mass index（BMI） was （24.7±3.8） kg/m2. Mean daily warfarin requirement was from 1.250 to 5.077 mg/day when therapeutic PT-INR （1.5-2.5） was maintained. DNA sequencing showed no polymorphisms of 608T/G, 561A/C, 537A/C, 527A/C inCYP2C9 exon 4. Warfarin daily dosage inCYP2C9 exon 4 -65C carriers was 3.106±0.619 mg/d, while it was （2.555±0. 708） mg/d in individuals with wild-type -65G （P=0.020）. Receiver operating characteristic （ROC） analysis showed that warfarin daily dosage of more than 2.5 mg/d can be used to predict the CYP2C9 exon 4 -65GC genotype （AUC：0.770,P=0.005,95%CI：0.626-0.915）. Logistic regression indicated that BMI was an independent factor of bleeding during anticoagulation therapy （OR=0.794, 95%CI：0.651-0.970, P=0.024）. Conclusion The Chinese population are, generally, warfarin-sensitive. Exon 4 of the CYP2C9 gene is highly conserved in this population. The warfarin maintenance dosage in CYP2C9 exon 4 - 65CG carriers was significantly higher than those with wild-type -65GG. The clinical significance needs further investigation with more large-scale, multi-center trials.