CYP2C19基因多态性与氯吡格雷抵抗的研究现状

氯吡格雷是目前治疗急性冠状动脉综合征的一种经典抗血小板药物,能降低冠心病患者尤其是支架术后患者的主要不良心血管事件的风险。但是部分患者存在氯吡格雷抵抗。研究认为,氯吡格雷抵抗受多因素影响,CYP2C19基因多态性是最重要的内部因素。CYP2C19*2和CYP2C19*3是亚洲人群最常见类型,CYP2C19基因变异者,氯吡格雷抗血小板效应减弱,不良心血管事件增加。因此,常规检测CYP2C19基因多态性可指导临床上氯吡格雷个性化用药。     

急性冠脉综合征PCI术后患者CYP2C19*2、CYP2C19*3基因多态性与氯吡格雷抵抗及临床预后的关系

目的 探讨急性冠脉综合征经皮冠状动脉介入治疗（Percutaneous Coronary Intervention,PCI）术后患者CYP2C19*2、CYP2C19*3基因多态性与氯吡格雷抵抗及临床预后的关系。方法 入选310例急性冠脉综合征行PCI术的患者,采用生物传感器基因芯片技术检测所有患者CYP2C19*2、CYP2C19*3基因型,根据基因型分为强代谢组（未携带突变基因,681GG/636GG）,中代谢组（携带一个突变基因,681GA/636GG,681GG/636GA）,弱代谢组（携带两个突变基因,681GA/636GA,681AA/636GG,681GG/636AA）。采用全流式细胞术定义氯吡格雷抵抗。分析各组之间氯吡格雷抵抗发生率的差异。观察各组12个月随访支架内血栓与心血管事件发生率。结果 强代谢组、中代谢组、弱代谢组分别为137例（44.2%）、134例（43.2%）、39例（12.6%）,三组之间氯吡格雷抵抗发生率有统计学差异。12个月随访中弱代谢组联合心血管不良事件发生率显著高于强代谢组(P<0.05),其中非致死心梗和支架内血栓发生率显著高于强代谢组(P<0.05),而死亡及再次血运重建率两组比较差异无统计学意义(P>0.05);中弱代谢组再次住院率也显著高于强代谢组。结论 急性冠脉综合征患者PCI术后CYP2C19*2、CYP2C19*3基因变异氯吡格雷抵抗发生率更高,支架内血栓及心血管不良事件发生率明显升高。     

Factors determining clinical effectiveness of clopidogrel and prognosis of patients with stable ischemic heart disease

Aim of the study was to elucidate genetic and drug factors affecting efficacy of clopidogrel in patients with ischemic heart disease - inhabitants of central region of Russian Federation. We included 399 patients with IHD (79% men, mean age 58.3+/-9 years) receiving long term therapy with clopidogrel 75 mg/day (during stable manifestations of the disease) or 75-150 mg/day in combination with aspirin (in relation with recent elective percutaneous interventions). We studied carriage of polymorphisms of genes controlling intestinal absorption of clopidogrel (ABCB1 C3435T), activation of clopidogrel in the liver (CYP2C19 *1 *2), and also registered concomitant administration of proton pump inhibitors (PPI). Then we determined relationship of these factors to development of vascular complications (vascular death/myocardial infarction/requirement in revascularization) during 18 months followup. Among studied genetic factors carriage of allele variants CYP2C19 *1/*2 and *2/* (found in 25.5 and 1.8% of patients, respectively), possessed prognostic significance. In the group of clopidogrel monotherapy carriage of at least one *2 allele was associated with increased rate of vascular complications (33.3% vs. 11.3%) including thrombotic complications (27.7% vs. 3.2%; =0.01). In patients receiving 75 mg/day of clopidogrel in combination with aspirin total rate of thrombotic complications as well as of all adverse unfavorable outcomes was higher in *2 carriers compared with wild type homozygotes (14.0% vs.8.7% and 21.0% vs. 15.8%, respectively). In patients receiving double dose clopidogrel in combination with aspirin we found no worsening of outcomes associated with CYP2C19*2 carriage. In the multifactorial risk model independent predictors of vascular complications turned out to be CYP2C19 *2/*2 homozygosity (RR 4.9; =0.02) and concomitant PPI administration ( 1.8; p=0.05).     

Genetic determinants of platelet response to clopidogrel

Antiplatelet agents are the mainstay treatment in the prevention and management of atherothrombotic complications. However, a substantial interpatient variability in response to clopidogrel has been reported. Furthermore, patients with coronary artery disease and lesser platelet inhibition in response to clopidogrel are at increased risk for cardiovascular events. Clopidogrel after absorption requires two-step oxidation by the hepatic cytochrome P450 to generate its active metabolite. Polymorphisms of genes encoding the cytochrome enzymes and P-glycoprotein involved in clopidogrel absorption are regarded as major determinants of the interindividual variability in the clopidogrel-induced platelet inhibition. In our review we discuss the prevalence and clinical significance of various alleles of the genes: CYP2C19 and ABCB1 in the setting of coronary artery disease. Allele CYP2C19*2 is associated with excess of ischaemic events including myocardial infarction and stent thrombosis. On the other hand, CYP2C19*17 allele poses a serious threat of bleeding. Data concerning the prognostic value of genetic variant 3435C→T of ABCB1 remain inconclusive.     

CYP2C19 genotype and adverse cardiovascular outcomes after stent implantation in clopidogrel-treated Asian populations: A systematic review and meta-analysis

The effect of CYP2C19 gene polymorphism on clinical outcomes of patients with coronary artery disease (CAD) treated with clopidogrel remains controversial. Ethnicity has been proposed to influence clopidogrel response following stent implantation in CAD patients with different CYP2C19 genotypes. Furthermore, Asian populations are reported to have a relatively greater prevalence of CYP2C19 loss-of-function (LOF) alleles. We aimed to evaluate the impact of CYP2C19 gene polymorphism on clinical outcomes in Asian populations who underwent percutaneous coronary interventions (PCI) and received clopidogrel therapy. We conducted a comprehensive search in PubMed, EMBASE, and Cochrane Library from their inceptions to January 20, 2017. Studies that reported clopidogrel therapy information, clinically relevant outcomes (adverse cardiovascular events, stent thrombosis and bleeding), and CYP2C19 genotypes among Asian populations were included. The primary endpoint was major adverse cardiovascular events (MACE), defined as a composite of cardiovascular death and myocardial infarction. The safety endpoint was any kind of bleeding. We retrieved 20 studies of 15056 patients reporting 1301 cardiovascular events. The primary analysis showed at least one CYP2C19 LOF allele (*2 and/or *3) carriers were at an increased risk of MACE compared with non-carriers (10.58% vs. 6.07%, OR: 1.99, 95% CI: 1.64 to 2.42, p < .001). Stent thrombosis (ST) was also more frequent in LOF allele carriers (2.22% vs. 0.44%, OR: 4.77, 95% CI: 2.84 to 8.01, p < .001). Inversely, the risk of bleeding was lower in LOF allele carriers (OR: 0.66, 95% CI: 0.46 to 0.96, p < .001). Subgroup analysis was performed to assess differences by high (600 mg) or routine (300 mg) loading dose of clopidogrel and by different nationalities. The risk of MACE in LOF allele carriers remained significantly higher even in high loading dose group (high loading dose: OR 1.72, 95% CI: 1.37 to 2.16, and routine loading dose: OR 2.22, 95% CI: 1.68 to 2.94, p for subgroup heterogeneity = 0.16). Subgroup analysis between three nationalities of China, Korea, and Japan demonstrated that the risk of MACE among Chinese LOF allele carriers was the greatest (OR: 2.28; 95% CI:1.91 to 2.73). In conclusion, among Asian populations with CAD undergoing stent implantation, CYP2C19 LOF allele carriers are at greater risk of adverse cardiovascular events and lower risk of bleeding compared with non-carriers. Genetic testing may be helpful for clinicians to personalize antiplatelet therapy especially in Asian population.     

Variant recurrent risk among stroke patients with different CYP2C19 phenotypes and treated with clopidogrel

Polymorphisms of CYP2C19 have been associated with variant risk of subsequent cardiovascular events in survivors of myocardial infarction (MI) receiving clopidogrel. This study evaluated the impacts of CYP2C19 polymorphisms on stroke recurrence and other vascular events in a cohort of Chinese patients receiving clopidogrel. From Nanjing Stroke Registry Program, 625 consecutive patients with ischemic stroke were enrolled between May 2008 and April 2010. CYP2C19 variants (*2, *3, and *17) were genotyped. Clinical outcomes were determined with three monthly follow-up. The primary endpoint was a composite of vascular death, non-fatal ischemic stroke, and non-fatal MI. The second endpoint was bleeding events. The median exposure to clopidogrel was 13.2 (interquartile range, 8.9–18.0) months. Primary endpoint was observed in 85 (13.6%) patients and secondary endpoint in 13 (2.1%) patients. Frequencies of CYP2C19*1, *2, *3, and *17 alleles were 61.2, 34.0, 3.8, and 1.0%, respectively, in this patient cohort. CYP2C19 loss-of-function allele (*2 and *3, LOF) carriers were observed with higher risk of subsequent vascular events compared with non-carriers (17.2 versus 8.1%, HR?=?2.16, 95% CI: 1.31–3.56, p?=?0.003). After adjusted for age, sex, major cardiovascular risk factors, and drug agent, CYP2C19 LOF carrier was independently associated with primary endpoint (HR?=?2.31, 95% CI: 1.39–3.84, p?=?0.001). No significant association between CYP2C19 gain-of-function (*17, GOF) and clinical events was detected. In Chinese stroke survivors treated with clopidogrel, carriers of CYP2C19 LOF allele may have increased risk of recurrence.     

细胞色素P4502C19基因多态性对介入术后服用氯吡格雷冠心病患者临床预后的影响

目的 探讨细胞色素P450(CYP)2C19 681G>A基因多态性对经皮冠状动脉介入治疗(PCI)后服用氯吡格雷冠心病患者临床预后的影响.方法 入选2009年1月1日至8月31日拟行PCI,并在术后服用氯吡格雷12个月的冠心病患者267例.采用MassARRAY时间飞行质谱检测入选患者CYP2C19 681G>A位点.按基因型不同,将患者分为CYP2C19*1/*1组 (n=130)和CYP2C19*2携带组(n=137).观察两组患者术后1年心绞痛复发、紧急血运重建术、急性心肌梗死、支架内血栓形成和死亡的发生情况.结果 两组患者的临床基本资料差异无统计学意义(P>0.05).PCI术后1年,CYP2C19*2携带组紧急血运重建术和联合终点事件的发生率均高于CYP2C19*1/*1组 (分别为7.3%比1.5%和8.0%比2.3%,P均<0.05).两组患者心绞痛复发、急性心肌梗死、支架内血栓形成和死亡的发生率差异均无统计学意义(P均>0.05).CYP2C19*2携带组随访1年的累积联合终点事件发生风险是CYP2C19*1/*1组的3.59倍(HR=3.59,95%CI:1.02～12.87,P<0.05).结论 CYP2C19 681G>A基因多态性可能是影响PCI术后服用氯吡格雷冠心病患者临床预后的因素.

Abstract：

Objective To investigate the impact of cytochrome P450 (CYP) 2C19 681G>A polymorphism on long-term prognosis of clopidogrel-treated Chinese patients after percutaneous coronary intervention (PCI).Methods Between January 1, 2009 and August 31,2009, 267 patients with coronary heart disease who received PCI and treated with clopidogrel for 12 months were enrolled. CYP2C19*2 was detected by MALDI-TOF MS and patients were grouped into CYP2C19*1/*1(n=130) and CYP2C19*2 carriers group (n=137). Follow-up was 12 months. The primary endpoint was angina recurrence, urgent coronary revascularization, acute myocardial infarction, stent thrombosis, death and the combined end points. Results Baseline data were similar between two groups (P>0.05).Urgent coronary revascularization and the combined end points occurred more frequently in CYP2C19*2 carriers than in CYP2C19*1/*1 patients (7.3% vs. 1.5% and 8.0% vs. 2.3% respectively,all P<0.05). But incidence of angina recurrence, acute myocardial infarction, stent thrombosis and death was similar between two groups (all P>0.05).Hazard risk of 1 year cumulative survival of CYP2C19*2 carriers group was significantly higher than CYP2C19*1/*1 group after PCI (HR=3.59, 95%CI: 1.02-12.87, P<0.05). Conclusion CYP2C19 681G>A polymorphism is a determinant of prognosis in coronary heart disease patients receiving chronic clopidogrel treatment after PCI.     

氯吡格雷抵抗与基因多态性

氯吡格雷是目前广泛应用于临床的一种抗血小板药,已作为心肌梗死、缺血性卒中和周围血管病的二级预防用药.然而,氯吡格雷的抗血小板聚集效果存在显著的个体差异,很大一部分患者存在抵抗现象.氯吡格雷抵抗的机制尚不完全清楚,基因多态性是氯吡格雷抵抗的一个重要原因,包括ABCB1、CYP2C19、CYP3 A4、CYP3A5、P2Y...     

High on-treatment platelet reactivity by ADP and increased risk of MACE in good clopidogrel metabolizers

High on-treatment platelet reactivity (HPR) by ADP, which primarily reflects the effect of thienopyridines, has been found to be an independent predictor of ischemic events in patients with acute coronary syndrome (ACS) on dual antiplatelet therapy. CYP2C19*2 is associated with HPR by ADP. The aim of our study was to evaluate if high on-clopidogrel platelet reactivity (HPR) by ADP is associated with an increased risk of major adverse coronary events (MACE) after ACS independent of CYP2C19*2 allele, i.e. whether genotyping patients for CYP2C19*2 polymorphism is sufficient to identify those to be switched to novel antiplatelets. A total of 1187 patients were included (CYP2C19 *1/*1 n?=?892; *1/*2 n?=?264; *2/*2 n?=?31); 76 MACE (CV death and non-fatal MI) were recorded in non-carriers of CYP2C19*2 (8.5%) and 39 in carriers of CYP2C19*2 (13.2%). At the landmark analysis in the first 6 months, HPR by ADP and CYP2C19*2 allele were both significantly and independently associated with MACE [HPR by ADP: HR?=?2.0 (95% CI 1.2–3.4), p?=?0.01; CYP2C19*2 allele: HR?=?2.3 (95% CI 1.3–3.9), p?=?0.003]. At the land mark analysis from 7 to 12 months, only HPR by ADP remained significantly associated with the risk of MACE [HPR by ADP: HR?=?2.7 (95% CI 1.4–5.3), p?=?0.003; CYP2C19*2: HR?=?0.8 (95% CI 0.2–1.1), p?=?ns]. CYP2C19*2 allele and HPR by ADP are both independently associated with an increased risk of MACE in the first 6 months after ACS. HPR by ADP is associated with an increased risk until 12 months of follow-up. Therefore, both phenotype and genotype are clinically relevant for the evaluation of the antiplatelet effect of clopidogrel and for the prognostic stratification of ACS patients.     

Comparison of ticagrelor and clopidogrel in the treatment of patients with coronary heart disease carrying CYP2C19 loss of function allele

BackgroundClopidogrel is a traditional P2Y12 receptor inhibitor that is widely used in clinical practice, but there are significant individual differences in its therapeutic effect. Carriers of the CYP2C19 deletion allele have a higher risk of adverse cardiovascular events than non-carriers.MethodsIn this study, 170 patients diagnosed with coronary heart disease (CHD) and on regular oral clopidogrel or ticagrelor antiplatelet therapy in the Department of Cardiology of Wuxi Second People’s Hospital from August to December 2019 were screened. Baseline patient data were collected, percutaneous coronary angiography (CAG) or coronary computed tomography angiography (CTA) results were recorded, CYP2C19 gene type was detected, and prognosis/outcome was assessed by telephone/outpatient/inpatient follow-up for 12 months.Results(I) Of the 170 patients, 0.66% were the fast metabolic type, 41.45% were the normal metabolic type, 42.76% were the intermediate metabolic type, and 15.13% were the poor metabolic type. CYP2C19*2 mutation accounted for 89.29% of all mutations, CYP2C19*3 mutation accounted for 9.82%, and CYP2C19*17 mutation accounted for only 0.89%. (II) Among the patients with CHD who regularly took clopidogrel, the risk in the intermediate metabolic group was 5.208-fold higher than that of normal metabolic group, and that of the poor metabolic group was 3.75-fold higher than that of normal metabolic group; there was no significant difference between the intermediate and poor metabolic groups. (III) Prognosis was significantly associated with regular use of ticagrelor or clopidogrel by patients in the intermediate metabolic group. There was no significant correlation between poor metabolism (PM) and normal metabolism (NM). Prognosis was significantly associated with regular use of ticagrelor or clopidogrel in patients undergoing percutaneous coronary intervention (PCI), but not in patients who did not undergo PCI.ConclusionsCYP2C19 polymorphism was associated with the prognosis of patients with CHD administered antiplatelet therapy with oral clopidogrel. The incidence of poor prognosis was significantly increased with CYP2C19*2 and/or CYP2C19*3 mutations, and patients undergoing PCI or carrying a single CYP2C19 deletion allele had a better prognosis with ticagrelor as replacement therapy.     

CYP2C19基因多态性与介入治疗后氯吡格雷药物疗效的相关性研究

目的探讨PCI术后CYP2C19基因多态性与不同剂量氯吡格雷药物效果的相关性。方法通过基因芯片检测技术,筛选PCI术后CYP2C19基因突变为CYP2C19*2/*2、CYP2C19*2/*3或CYP2C19*3/*3的患者67例,随机分为常规组22例、2倍组22例和3倍组23例。常规组75 mg氯吡格雷、2倍组150 mg氯吡格雷、3倍组225 mg氯吡格雷,1次/d。分别于PCI术后1、3、6个月通过血栓弹力图检测各组氯吡格雷药物抑制率及再发心血管缺血事件发生率。结果 PCI术后6个月内,2倍组和3倍组患者心血管缺血事件发生率较常规组明显降低(81.8%vs 31.8%vs 21.7%,P<0.01),2倍组与3倍组比较差异无统计学意义(P>0.05)。术后1、3、6个月2倍组和3倍组氯吡格雷药物抑制率较常规组显著升高(P<0.01),2倍组与3倍组比较差异无统计学意义(P>0.05)。3组出血风险比较差异无统计学意义(P>0.05)。结论 CYP2C19基因变异患者增加氯吡格雷药物服用剂量,可在一定程度上提高血小板的抑制,降低心血管缺血事件发生率,且不增加出血事件的发生率。     

CYP2C19*2 and prognosis after an acute coronary syndrome: Insights from a Portuguese center

BackgroundClopidogrel requires oxidation dependent on the cytochrome P450 enzyme 2C19 (CYP2C19) to form its active metabolite. The importance of loss-of-function alleles (particularly CYP2C19*2, 681G>A) in poor platelet response to clopidogrel is well recognized.ObjectiveTo investigate the prevalence and prognostic impact of the CYP2C19*2 allele in a local acute coronary syndrome (ACS) population.MethodsWe performed a prospective, longitudinal study of 95 patients admitted for an ACS between March and October 2009 to a single coronary care unit. Patients aged under 75 who survived hospital stay and for whom clopidogrel was prescribed were included. At discharge, CYP2C19 was genotyped using a commercially available kit. Patients were divided into two groups: Group A (non-carriers, normal metabolizers, CYP2C19*1/*1), n = 69; and Group B (carriers, slow metabolizers, CYP2C19*2/*1 or *2/*2), n = 26. The primary endpoint was a combined outcome of cardiovascular death, non-fatal myocardial infarction or re-admission for unstable angina; median follow-up was 136.0 (79.0–188.0) days.ResultsThe median age of the population was 62.0 (51.0–68.0) years, and 83.2% were male. The CYP2C19*2 (A) allele had a frequency of 14.2%. There were no differences between the groups with respect to demographic data or history of cardiovascular disease. Coronary anatomy, left ventricular ejection fraction and renal function were also similar. The groups were also homogenous with respect to GRACE risk score (118.0 (95.0–136.5) vs. 115.0 (96.0–133.0), p = 0.68), medical treatment and percutaneous revascularization during hospital stay. Event-free survival was higher for Group A (94.0% vs. 75.0%, log-rank p = 0.010). Three readmissions for MI were documented, all in the slow metabolizers group.ConclusionIn our ACS population, the CYP2C19*2 allele was a medium-term prognostic marker.     

Multisite Investigation of Outcomes With Implementation of CYP2C19 Genotype-Guided Antiplatelet Therapy After Percutaneous Coronary Intervention

Objectives

This multicenter pragmatic investigation assessed outcomes following clinical implementation of CYP2C19 genotype–guided antiplatelet therapy after percutaneous coronary intervention (PCI).

CYP2C19基因多态性与氯吡格雷抵抗的研究进展

氯吡格雷是治疗急性冠脉综合征的一种经典抗血小板药物,但是临床观察到部分患者不能从氯吡格雷的治疗中获益,从而提出了氯吡格雷抵抗（CR）的问题。目前研究认为,CR受多因素影响,其中CYP2C19基因的多态性是最重要的内部因素。CYP2C19基因变异者,氯吡格雷的活性代谢产物减少,抗血小板效应减弱,不良心血管事件增加。而CYP2C19＊2和CYP2C19＊3是亚洲人最常见类型,因此,探讨CYP2C19基因的多态性对氯吡格雷疗效的影响具有临床意义。     

Genetic determinants of on-clopidogrel high platelet reactivity

Clopidogrel has been used (alone or in association with aspirin) to prevent vascular complications in atherothrombotic patients, to prevent stent thrombosis (ST) in patients undergoing percutaneous coronary intervention (PCI) and as a long-term prevention of cardiovascular and cerebrovascular events. Unfortunately, it is important to note that there are a number of patients who, during clopidogrel therapy, show and maintain a high platelet reactivity (PR), similar to that observed before the start of antiplatelet therapy. Clopidogrel pro-drug is absorbed in the intestine and this process is influenced by P-glycoprotein-1 (P-GP). Its conversion into 2-oxo clopidogrel is regulated by cytochromes (CYP) called CYP2C19, CYP2B6 and CYP1A2. Whereas, the final transformation into the active metabolite is regulated by CYP called CYP2C19, CYP2C9, CYP2B6, CYP3A4, CYP3A5 and, as recently emerged, by the glycoprotein paraoxonase-1 (PON1). The genes encoding these enzymes are characterized by several polymorphisms. Some of these are able to modify the activity of proteins, reducing the concentration of active metabolite and the values of on-clopidogrel PR. Only one gene polymorphism (CYP2C19*17) increases the clopidogrel metabolization and so the clopidogrel-induced platelet inhibition. Several studies have clearly associated these gene polymorphisms to both ischemic and bleeding complications in patients receiving dual antiplatelet therapy. The aim of this review is to describe the principal gene polymorphisms influencing on-clopidogrel PR and their relationship with long-term clinical outcome.     

Effect of cytochrome p450 polymorphisms on platelet reactivity after treatment with clopidogrel in acute coronary syndrome

Genetic polymorphisms of cytochrome P450 (CYP) isoforms may promote variability in platelet response to clopidogrel. This study was conducted to analyze, in 603 patients with non-ST elevation acute coronary syndromes, the effect of CYP3A4, CYP3A5, and CYP2C19 gene polymorphisms on clopidogrel response and post-treatment platelet reactivity assessed by adenosine diphosphate (ADP)-induced platelet aggregation, vasodilator-stimulated phosphoprotein phosphorylation index, and ADP-induced P-selectin expression. The CYP2C19*2 polymorphism was significantly associated with ADP-induced platelet aggregation, vasodilator-stimulated phosphoprotein phosphorylation index, and ADP-induced P-selectin expression in recessive (p <0.01, p <0.007, and p <0.06, respectively) and codominant (p <0.08, p <0.0001, and p <0.009, respectively) models, but the CYP3A4*1B and CYP3A5*3 polymorphisms were not. The CYP2C19*2 allele carriers exhibited the highest platelet index levels in multivariate analysis (p = 0.03). After covariate adjustment, the CYP2C19*2 allele was more frequent in clopidogrel nonresponders, defined by persistent high post-treatment platelet reactivity (ADP-induced platelet aggregation >70%; p = 0.03). In conclusion, the present data suggest that the CYPC19*2 allele influences post-treatment platelet reactivity and clopidogrel response in patients with non-ST elevation acute coronary syndromes.     

Cytochrome P450 2C19 loss-of-function polymorphism is a major determinant of clopidogrel responsiveness in healthy subjects

The capacity of clopidogrel to inhibit ADP-induced platelet aggregation shows wide intersubject variability. To determine whether frequent functional variants of genes coding for candidate cytochrome P450 (CYP) isoenzymes involved in clopidogrel metabolic activation (CYP2C19*2, CYP2B6*5, CYP1A2*1F, and CYP3A5*3 variants) influence the platelet responsiveness to clopidogrel, we conducted a prospective pharmacogenetic study in 28 healthy white male volunteers treated for 7 days with clopidogrel 75 mg/d. We observed that pharmacodynamic response to clopidogrel was significantly associated with the CYP2C19 genotype. Twenty of the subjects were wild-type CYP2C19 (*1/*1) homozygotes, while the other 8 subjects were heterozygous for the loss-of-function polymorphism CYP2C19*2 (*1/*2). Baseline platelet activity was not influenced by the CYP2C19 genotype. In contrast, platelet aggregation in the presence of 10 muM ADP decreased gradually during treatment with clopidogrel 75 mg once daily in *1/*1 subjects, reaching 48.9% +/- 14.9% on day 7 (P < .001 vs baseline), whereas it did not change in *1/*2 subjects (71.8% +/- 14.6% on day 7, P = .22 vs baseline, and P < .003 vs *1/*1 subjects). Similar results were found with VASP phosphorylation. The CYP2C19*2 loss-of-function allele is associated with a marked decrease in platelet responsiveness to clopidogrel in young healthy male volunteers and may therefore be an important genetic contributor to clopidogrel resistance in the clinical setting.     

Polymorphisms of MDR1, CYP2C19 and P2Y12 genes in Indian population: Effects on clopidogrel response

Aims/objectiveInfluence of genetic variations on the response of clopidogrel, an antiplatelet drug is implicated. In the present study, the prevalence of single nucleotide polymorphisms of MDR1 (C3435T), CYP2C19 [CYP2C19*2 CYP2C19*3, CYP2C19*17] and P2Y₁₂ (i-T744C) in Indian population and their effects on clopidogrel response was analyzed.Methods and resultsTo analyze the prevalence of polymorphisms, 102 healthy individuals were recruited. Clopidogrel response was assessed by ADP induced platelet aggregation in clopidogrel naïve acute myocardial infarction (AMI) patients (n = 26) screened from 100 AMI cases, before loading dose of 300 mg, at 24 h before next dose and 6 days after on 75 mg per day and platelet aggregation inhibition (PAI) was calculated between these time intervals. Genotyping was carried out by PCR-based restriction enzyme digestion method for C3435T of MDR1 and i-T744C of P2Y₁₂, by multiplex PCR for CYP2C19*2 (G681A) and CYP2C19*3 (G636A) and by nested PCR for CYP2C19*17 (C806T). The effect of the above mentioned genetic variations on PAI was analyzed. Variant allele of CYP2C19*3 was not observed while the prevalence of 3435T of MDR1 (0.524), CYP2C19*2 (681A, 0.352); i-744C of P2Y₁₂ (0.088), as well as wild type allele CYP2C19*17 (C806, 0.897) associated with decrease clopidogrel response were observed. Trend toward poor response to clopidogrel was observed at 24 h with the variant genotypes of CYP2C19*2 and i-T744C of P2Y₁₂ as compared to wild type.ConclusionThe present study did show a trend toward impaired response of clopidogrel to inhibit platelet aggregation with variant genotypes of CYP2C19*2 and iT744C of P2Y₁₂ compared to respective wild type genotype at 24 h.     

CYP2C19＊2基因多态性与经皮冠状动脉介入治疗后氯吡格雷抗血小板临床疗效的相关性

目的探讨CYP2C19＊2（c．681G〉A,rs4244285）基因多态性与经皮冠状动脉介入（percutaneouscoronaryintervention,PCI）治疗后氯吡格雷抗血小板临床疗效的相关性。方法选择478例接受PCI治疗的急性冠脉综合征（acutecoronarysyndrome,ACS）患者,采用TaqMan基因分型技术检测其CYP2C19＊2的基因多态性。患者术后均采用氯吡格雷抗血小板治疗并定期随访,分析不同基因型与PCI治疗后支架内血栓、主要心血管事件（majoradversecardiacevents,MACE）发生率及生存时间的相关性。采用COX单因素分析检测PCI治疗后发生MACE的相关因素,采用COX多因素分析检测PCI治疗后MACE的危险因素。结果本研究人群中的CYP2C19＊2的基因型分布符合Hardy—Weinberg平衡。478例患者纯合野生型（GG）238例（49．8％）,杂合型（GA）加纯合突变型（AA）240例（50．2％）。分析结果显示,对于支架内血栓（P=0．025）及MACE（P=0．09）,携带681GG基因型的患者预后较携带681A等位基因（AA／AG基因型）的好。单因素COX回归结果显示,CYP2C19＊2的基因型、糖尿病病史、原发性高血压（高血压）病史[RR（95％CI）为2．796（1．245—6．281）、2．157（1．039—4．478）和3．564（1．364-9．312）]是发生MACE的相关因素。多因素COX回归分析结果显示,CYP2C19＊2的基因型、高血压病史是发生MACE的危险因素。结论CYP2C19＊2的基因多态性与PCI治疗后氯吡格雷抗血小板临床疗效有关,CYP2C19＊2基因突变能够降低氯吡格雷抗血小板效果,增加PCI治疗后发生支架内血栓、MACE的风险。