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.

Effect of HFE gene polymorphism on sustained virological response in patients with chronic hepatitis C and elevated serum ferritin / Efeito do polimorfismo do gene HFE sobre a resposta viral sustentada em portadores de hepatite crônica C com ferritina sérica elevada

CONTEXT: Abnormal serum ferritin levels are found in approximately 20%-30% of the patients with chronic hepatitis C and are associated with a lower response rate to interferon therapy. OBJECTIVE: To determine if the presence of HFE gene mutations had any effect on the sustained virological response rate to interferon based therapy in chronic hepatitis C patients with elevated serum ferritin. METHODS: A total of 44 treatment naÏve patients with histologically demonstrated chronic hepatitis C, all infected with hepatitis C virus genotype non-1 (38 genotype 3; 6 genotype 2) and serum ferritin above 500 ng/mL were treated with interferon (3 MU, 3 times a week) and ribavirin (1.000 mg, daily) for 24 weeks. RESULTS: Sustained virological response was defined as negative qualitative HCV-RNA more than 24 weeks after the end of treatment. Serum HCV-RNA was measured by qualitative in house polymerase chain reaction with a limit of detection of 200 IU/mL. HFE gene mutation was detected using restriction-enzyme digestion with RsaI (C282Y mutation analysis) and BclI (H63D mutation analysis) in 16 (37%) patients, all heterozygous (11 H63D, 2 C282Y and 3 both). Sustained virological response was achieved in 0 of 16 patients with HFE gene mutations and 11 (41%) of 27 patients without HFE gene mutations (P = 0.002; exact Fisher test). CONCLUSION: Heterozigozity for H63D and/or C282Y HFE gene mutation predicts absence of sustained virological response to combination treatment with interferon and ribavirin in patients with chronic hepatitis C, non-1 genotype and serum ferritin levels above 500 ng/mL.

CONTEXTO: Níveis séricos anormais de ferritina são encontrados em aproximadamente 20%-30% dos pacientes com hepatite crônica C e estão associadas a uma baixa taxa de resposta à terapia com interferon. OBJETIVO: Avaliar a associação entre a presença de mutações do gene HFE e a taxa de resposta virológica sustentada ao interferon em pacientes portadores de hepatite crônica C com ferritina sérica elevada. MÉTODOS: Um total de 44 pacientes, virgem de tratamento, infectado pelo vírus da hepatite C de genótipos não-1 (38 genótipo 3; 6 genótipo 2) e ferritina sérica acima de 500 ng/mL foi tratado com interferon (3 MU, três vezes por semana) e ribavirina (1000 mg/dia) por 24 semanas. Resposta virológica sustentada foi definida como HCV-RNA indetectável 24 semanas após o fim do tratamento. Foi utilizado técnica de reação em cadeia da polimerase em tempo-real com limite de detecção de 200 UI /mL. RESULTADOS: Mutações do gene HFE foram detectadas por "restriction-enzyme digestion" com RsaI (análise de mutação C282Y) e BclI (análise de mutação H63D) em 16 pacientes (37%), todos heterozigotos (11 H63D, 2 C282Y e 3 ambos). Resposta virológica sustentada foi alcançada em 0 de 16 pacientes com mutações do gene HFE e 11 (41%) dos 27 pacientes sem mutações do gene HFE (P = 0,002; teste exato de Fisher). CONCLUSÃO: A heterozigose para os genes H63D e/ou C282Y HFE está associada à redução significativa da taxa de resposta virológica sustentada ao tratamento com interferon e ribavirina em pacientes com hepatite crônica C, genótipo não-1 e com níveis séricos de ferritina acima de 500 ng/mL.

Study on the polymorphysm of MTHFR gene in coronary heart disease in Guizhou / 中国实用内科杂志

Objective Study on methylenetetrahydrofolate reductase(MTHFR)gene polymorphism in coronary heart disease.Methods Detect the MTHFR C677T gene polymorphism by PCR-RFLP in 73 cases of healthy individuals and 87 cases of coronary heart diseas(CHD).Results At the site of 677,the T allele frequencies are 18.5%,36.1%,respectively,for healthy individuals and 87 cases of coronary heart disease.The frequecies of MTHFR CT genotype and T allel were significantly higher in disease groups.There are significant differences between disease group and control group(P