Association of CYP2C19*2 polymorphism with clopidogrel resistance among patients with high cardiovascular risk in Northeastern Mexico / Asociación del polimorfismo CYP2C19*2 con resistencia a clopidogrel en pacientes con alto riesgo cardiovascular en el noreste de México

abstract Objective: Oral antiplatelet drugs are a key to modern pharmacotherapy in cardiovascular atherothrombotic diseases. Clopidogrel (CLO) constitutes the main preventive treatment of atherothrombosis. However, a considerable inter-individual variation in CLO response has been documented, resulting in suboptimal therapy and an increased risk of recurrent adverse effects in some patients. The enzyme CYP2C19 has been reported to be the CYP isoform that activates CLO to its active metabolite. Several single nucleotide polymorphisms in the CYP2C19 gene have been identified as strong predictors of CLO-impaired pharmacological response. At least 16 variants have been associated with changes in CYP2C19 activity. Materials and Methods: The following research was composed of a total of 102 subjects with high cardiovascular risk in the northeast of Mexico, with a maintenance dose of 75 mg of CLO per day. The platelet reactivity was measured with VerifyNow P2Y12 assay, while the presence of CYP2C19*2 was identified by real-time polymerase chain reaction. Results: Patients were categorized by CYP2C19 metabolizer status based on *2 genotypes using the common consensus star allele nomenclature as normal metabolizer (G/G), intermediate metabolizer (G/A), and poor metabolizer (A/A), respectively. The phenotype frequency for CYP2C19*2 was 74.5% (G/G), 21.6% (G/A), and 3.9% (A/A). The subjects with the A allele presented ≥235 P2Y12 reaction unit levels, classifying them how poor metabolizer. The prevalence of reduced CLO effectiveness was associated with the presence of CYP2C19*2 polymorphism among Mexican patients. Conclusion: The presence of the CYP2C19*2 allele is related to resistance to the antiplatelet effect of CLO (p = 0.003).

Resumen Objetivo: Los antiplaquetarios orales son clave en la farmacoterapia moderna de las enfermedades aterotrombóticas cardiovasculares. Clopidogrel (CLO) constituye el principal tratamiento preventivo de aterotrombosis (AT). Sin embargo, se ha documentado una considerable variación interindividual en la respuesta a CLO, lo que da como resultado una terapia subóptima y mayor riesgo de efectos adversos en algunos pacientes. La enzima CYP2C19 es la isoforma CYP que activa CLO a su metabolito activo. Se han identificado varios polimorfismos de un solo nucleótido en el gen CYP2C19 como fuertes predictores de respuesta farmacológica alterada a CLO. Al menos 16 variantes se han asociado con cambios en la actividad de CYP2C19. Método: Se reclutaron un total de 102 sujetos con alto riesgo cardiovascular del noreste de México, con dosis de mantenimiento de 75 mg de CLO/día. La reactividad plaquetaria se midió con el ensayo Verify Now P2Y12, la presencia de CYP2C19*2 se identificó mediante polymerase chain reaction en tiempo real. Resultado: Los pacientes fueron clasificados por el estado metabolizador CYP2C19*2 utilizando nomenclatura consenso, como metabolizador normal (G/G), metabolizador intermedio (G/A) y metabolizador pobre (A/A), respectivamente. La frecuencia del fenotipo para CYP2C19*2 fue 74.5% (G/G), 21.6% (G/A) y 3.9% (A/A). Los sujetos con alelo A presentaron ≥235 niveles P2Y12 reaction unit, clasificándolos como metabolizadores deficientes. La prevalencia de eficacia reducida a CLO se asoció con la presencia del polimorfismo CYP2C19*2 en pacientes mexicanos. Conclusiones: La presencia del alelo CYP2C19*2 se relaciona con resistencia al efecto antiagregante plaquetario del CLO (p = 0.003).

Association of CYP2C19 gene polymorphism with anastrozole in treatment of postmenopausal breast can-cer patients / 实用医学杂志

Objective To investigate the correlation between CYP2C19*2 gene polymorphism and efficacy of anastrozole in postmenopausal women with breast cancer. Methods The polymorphisms of CYP2C19*2 gene in postmenopausal women with postmenopausal breast cancer were detected by PCR. Results The A allele frequency of the CYP2C19*2 gene(OR=3.146,95% CI:1.244~7.275,P<0.05)was a risk factor for the efficacy of post-menopausal breast cancer patients.The survival rate was lower than that of GG(χ2=6.26,P<0.05).After treat-ment,the FSH and LH of GG patients were significantly lower than those of AA and GA(t=5.29,6.47,P<0.05). Multivariate logistic regression analysis showed that anastrozoleand CYP2C19*2 gene polymorphism were indepen-dently associated with serum FSH and LH levels in postmenopausal women with breast. Conclusion CYP2C19*2 gene polymorphism is associated with anastrozole in the treatment of postmenopausal breast cancer.

Evaluation of clopidogrel response variability and identification of the CYP2C19 polymorphism in Mexican patients / Evaluación de la variabilidad en la respuesta a clopidogrel e identificación del polimorfismo CYP2C19 en pacientes mexicanos

Abstract Objective Drug inhibition of platelet P2Y12 adenosine diphosphate receptor has reduced the incidence of adverse cardiovascular events after percutaneous coronary interventions. The analysis of the phosphorylation status of vasodilator-stimulated phosphoprotein by flow cytometry has shown a predictive value for adverse events and stent thrombosis. Polymorphisms of CYP2C19 in high risk patients may also relate to adverse cardiovascular events. Methods Ninety patients were enrolled. Patients received a 600 mg clopidogrel loading dose. Blood samples were obtained at the time of the procedure and 24 h later, platelet reactivity was assessed by vasodilator-stimulated phosphoprotein phosphorylation measurement using flow cytometry. Low response to clopidogrel was defined as a platelet reactivity index ≥ 50%. The presence of CYP2C19*2 was identified with the restriction enzyme Smal. Results Mean platelet reactivity index: 53.45 ± 22.48% in the baseline sample and 57.14 ± 23.08% at 24 h (p = 0.183); 40% of patients behaved as good responders, the rest behaved as non-responders with 38% of patients showing platelet reactivity indexes between 50-70% and 22% showing indexes above 70%. The CYP2C19*2 polymorphism was found in 17% of patients, with a 3.9% AA homozygous genotype carriers. Conclusion Response to the clopidogrel loading dose showed a wide variability among patients with 40% responding to the drug according to previously established cut-off values. Our results showed that 3.9% of patients show the AA genotype. To our knowledge, this is the first study involving clopidogrel response by flow citometry and genotype typification in Mexican Mestizo population.

Resumen Objetivo La inhibición del receptor plaquetario P2Y12 se ha asociado con reducción en incidencia de eventos cardiovasculares mayores en pacientes sometidos a intervenciones coronarias percutáneas. El estudio de la fosfoproteína estimulada por vasodilatadores mediante citometría de flujo tiene valor predictivo para desarrollo de eventos adversos y trombosis del stent. Los polimorfismos del CYP2C19 en pacientes de alto riesgo pueden también asociarse con eventos adversos. Método 90 pacientes, dosis de carga de clopidogrel: 600 mg. Se obtuvieron muestras de sangre basales y post-24 horas. La reactividad plaquetaria se estudió mediante medición de fosfoproteína estimulada por vasodiatadores por citometría de flujo. Se consideró baja respuesta al clopidogrel un índice de reactividad plaquetaria ≥50%. La presencia del CYP2C19*2 se identificó con enzima de restricción Smal. Resultados La media del índice de reactividad plaquetaria fue: 53.45 ± 22.48% en muestras basales y 57.14 ± 23.08% a 24 h (p = 0.183); 40% de los pacientes repondieron a clopidogrel, el resto de comportó como no-respondedores, un 38%, mostró índices de reactividad plaquetaria entre 50 -70% y 22%, índices > 70%. El polimorfismo CYP2C19*2 se encontró en 17% pacientes, con un 3.9% portadores de genotipo homozigótico AA. Conclusiones La respuesta a clopidogrel mostró amplia variabilidad entre pacientes, el 40% presentó respuesta de acuerdo con puntos de corte pre establecidos. Un 3.9% de los pacientes presentó genotipo AA. Consideramos que este es el primer estudio realizado en población mestizo-mexicana utilizado citometría de flujo para evaluar la respuesta a clopidogrel así como la tipificación genética de los pacientes.

Correlation study of gene polymorphism of CYP2 C19 and clopidogrel response after percutaneous translu-minal angioplasty and stenting in patients with ischemic cerebrovascular disease / 医学研究生学报

Objective There is little research on the relationship of gene polymorphism of CYP2C19 and clopidogrel response after percutaneous transluminal angioplasty and stenting ( PTAS) in patients with ischemic cerebrovascular disease.The study aimed to investigate the relationship between gene polymorphism and high on-treatment platelet reactivity ( HTPR ) after PTAS and 6 months of regular dual antiplatelet administration in patients. Methods A total of 145 Chinese patients treated with PTAS in our de-partment from January 2011 to March 2014 were enrolled in this study.According to the gene sequencing, patients were divided into wild-type group(CYP2C19*1/*1,69 cases) and mutation group(heterozygous mutation CYP2C19*1/*2 and homozygous mutation CYP2C19*2/*2, 76 cases).Patients received a 100mg/d aspirin and 75mg/d clopidogrel maintenance dose (MD) as dual anti-platelet therapy after PTAS.The clopidogrel inhibition effect was measured by thrombelastography ( TEG) system 6 months after PTAS. Routine cerebral artery digital subtraction angiography was applied to evaluate whether there was restenosis in stent and logistic regres-sion analysis was used to analyze the influential factors of HTPR after PTAS and clopidogrel adminstration. Results After 6 months'regular administration of clopidogrel after PTAS, the platelet adenosine diphosphate ( ADP ) receptor inhibition rates in wild-type group, heterozygous mutation and homozygous mutation group were respectively (58.43 ±21.98)%, (47.80 ±22.93)%, (37.53 ± 21.84)%.The platelet ADP receptor inhibition rate was significantly decreased compared with wild-type group(P=0.001).Carriers of at least one CYP2C19 loss-of-function ( LOF) allele had a higher frequency of clopidogrel HTPR (35.5% vs17.4 % for patients with and without LOF alleles, respectively;P=0.014) .Using multivariate logistic regression analysis, the carriage of CYP2C19 LOF alleles was an independent predictor of the post-procedure HTPR (OR=2.356, 95% CI:1.053-5.272, P=0.037).The rate of ISR was remarkably higher in patients with at least one CYP2C19*2 alleles compared with wild-type patients(11.8%vs 1.4%, P=0.019) . Conclusion In patients with ischemic cerebrovascular disease, the CYP2C19 LOF allele had significant impact on post-procedure clopidogrel HTPR and the prognosis of ISR after PTAS.