| Objective:To explore the effects the polymorphisms involved in the metabolic process(ABCB1,CES1A2,CYP2C19,CYP3A4 and CYP3A5)on the clopidogrel response and clinical vascular events in ischemic stroke patients from Southeast Chinese Han population.Methods:Between February 2012 and February 2014,patients diagnosed as acute ischemic stroke in Nanjing Jinling hospital were selected prospectively for this study.Demographic characteristics,medical history and medication were recorded and registered in Nanjing Stroke Registry Program.The cubital venous blood was gained at the next morning after admission in the study for routine blood examination and extraction of DNA samples.After 5 days of continuous administration of clopidogrel,the platelet inhibitive rate was measured by thrombelastography(TEG).Genotypes was determined by the modified Multiplex Ligase Detection Reaction method(iMLDR).Among all samples,10%were randomly selected for repeated genotyping,and the results were 100%concordant.The technicians performing genotyping were blinded to the platelet inhibition rate and clinical outcome.The relationships between the gene polymorphisms and platelet inhibitive rate were analyzed with one-way analysis of variance and multivariate linear regression.An initial follow-up was conducted and recorded in Nanjing Stroke Registry Program for each subject at three months after enrollment by outpatient visit or telephone interview,with a detailed report of drug treatment.We excluded those who changed anti-platelet regime or disruption antiplatelet agents.The patients were further evaluated at 6,12,and 24 months after enrollment by phone interview or clinical visit.The primary endpoint was a composite of vascular death,acute myocardial infarction and recurrent ischemic stroke.We recorded the incidence of primary endpoint during the follow-up period.The end-point was adjudicated by a physician who was unaware of the genotype and platelet function of the patients.Follow-up was censored when the primary endpoint was identified,clopidogrel discontinued,or the two-year follow-up completed.The deadline of follow-up period was December 2014.The associations between the genotype and primary endpoint were evaluated by the Kaplan-Meier method.The independent risk factors of the primary endpoint were analyzed by the Cox proportional hazards model.The statistical analyses were performed by the SPSS 22.0 software.Two-sided P-values<0.05 indicated statistical significance.Results:During the two-years study period,208 acute ischemic stroke patients treated with clopidogrel were included.Among the 208 enrolled patients,the mean age at baseline was 61.2 ± 10.3 years old,and the median score of NIHSS at baseline was 3 and interquartile range was 4.One hundred and forty(67.3%)subjects were males,77(37.0%)have diabetes mellitus and 132(63.5%)have hypertension.The platelet inhibitive rate in patients with homozygous(TT)of ABCB1 C3435T(42.7%± 13.8%)was significantly lower than that in patients with heterozygous TC(53.1%±21.2%)and wild-type genotypes(CC:58.1%± 21.1%;P = 0.006).As for CES1A2 A(-816)C,the rate of platelet inhibition in patients with homozygous(CC)(30.3%±12.2%)was significant lower than that in heterozygous(AC)(54.7%± 26.7%)and wild-type genotype(AA)(55.0%± 23.0%)in co-dominant model(P = 0.021).The inhibitive rate decreased according to the CYP2C19 genotype(59.3%± 23.2%,51.8%± 25.4%,and 44.5%± 22.6%in the EM(extensive-metabolizers,non-carrier),IM(intermediate-metabolizers,one*2 or*3 alleles)and PM(poor-metabolizers,two*2 or*3 alleles)individual,respectively,P = 0.015).For genotypes of CYPA3P5,the rate of platelet inhibition in patients with wild-type(CC)of CYPA3P5,heterozygous(CT)and homozygous(TT)was 53.7%± 25.2%,53.6%± 24.1%,and 56.4%± 24.4%.The difference between the three groups was not statistically significant.There was no statistically significant difference among the subtypes of ABCB1 T(-620)C.As for CYPA3P4 gene,the frequency of gene mutation was very low(only observed in one case).Thus the difference of the platelet inhibitive rate was not compared.In addition,a multivariable linear regression model demonstrated that the ABCB1 C3435T,CYP2C19 2/*3 and CES1A2 polymorphisms were independently associated with the platelet inhibitive rate determined by TEG.After excluding patients who changed anti-platelet regime and lost follow-up,the data of 191 patients were analyzed by survival analysis.Kaplan-Meier analysis showed that the risks of primary endpoint were increased in CES1A2 A(-816)C allele and CYP2C19 LOF(at least one LOF)allele carriers during the follow-up(P = 0.023 and 0.028,respectively).For CYPA3P5(rs776746)and ABCB1(rs4148727 and rs1045642),the Log rank test was not statistically significant in any genetic models.Multivariable Cox regression analysis showed that the adjusted hazard ratio of primary endpoint for patients with CES1A2 A(-816)C(CC)allele carriers was 3.536(95%CI:1.049-11.915,P-0.042)and 2.907(95%CI:1.095-7.718,P = 0.032)for CYP2C19 LOF allele carriers.In addition,the age was also found to be independent risk factors for the primary endpoint events(HR = 1.050,95%CI:1.009-1.094;P = 0.021).There was no significant relationship between the polymorphisms of ABCB1 C3435T,ABCB1 T(-620)C,CYPA3P4(rs35599367),CYPA3P5(rs776746)and the primary endpoint.Conclusions:For Chinese acute ischemic stoke patients who carried CYP2C19 LOF alleles or CESIA2 A(-816)C,the effect of clopidogrel was decreased and risk of ischemic events was increased.There were no significant correlation between ABCB1 T(-620)C,CYPA3P4(rs35599367)and CYPA3P5(rs776746)polymorphisms and clopidogrel effect. |
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