Effects of different CYP2C19 genotypes on prognosis of patients complicated with atrial fibrillation taking clopidogrel after PCI

Genetic variability in stroke patients: CYP2C19 polymorphisms unraveled

OBJECTIVE

To study the distribution characteristics of CYP2C19 polymorphisms in patients suffering from stroke in Han Chinese patients.

METHOD

PCR and DNA microarray chip technology were used to detect the CYP2C19 genotype of 549 patients with stroke, and the genotype, allele frequency and metabolic type of patients with different sexes, ages and types of infarctions and the independent risk factors for clopidogrel resistance were analyzed.

RESULTS

Six genotypes were detected in these 549 patients. A total of 233 (42.44%) patients had the heterozygous allele *1/*2, which was the most prevalent, followed by the homozygous wild-type allele *1/*1 (191, 34.79%). A total of 30 (5.46%) patients possessed the heterozygous allele *1/*3, and 65 (11.84%) patients had the homozygous mutant allele *2/*2. Twenty-nine (5.28%) patients had the compound heterozygous mutant allele *2/*3, and only 1 patient had the homozygous mutant allele *3/*3. The distribution of genotypes, alleles, and metabolic types did not change significantly (P > 0.05) by sex, age, or type of stroke. In addition, no independent risk factors for clopidogrel resistance were found in this analysis.

CONCLUSION

The distribution of CYP2C19 genotypes, allele frequencies, and metabolic types in patients with stroke in Han Chinese patients were not correlated with sex, age, or infarction type. The possibilities of hyperglycemia, hypercholesterolemia, hypertriglyceridemia, hypo-HDL-cholesterolemia, hyper-LDL-cholesterolemia and high blood pressure were not statistically associated with CYP2C19 genotypes. CYP2C19 gene polymorphism detection is recommended for patients who are available, and during treatment, the CYP2C19 genotype can be used to guide personalized precise medication use in patients with stroke.

A novel AllGlo probe-quantitative PCR method for detecting single nucleotide polymorphism in CYP2C19 to evaluate the antiplatelet activity of clopidogrel

CYP2C19 gene has multiple single nucleotide polymorphism (SNP), which is the major determinant for clopidogrel treatment responses. Therefore, CYP2C19 SNP detection is essential for predicting clopidogrel efficacy. Currently, there is still no quick and effective method for routine detection of common CYP2C19 SNPs in clinical laboratories, which is critically needed prior to clopidogrel treatment. AllGlo™ based quantitative PCR was used to develop a novel genotyping method for CYP2C19 SNP detection, termed CyPAllGlo. The performance of CyPAllGlo was compared with that of the commonly used fluorescence in situ hybridization (FISH) method, and the data was verified by DNA sequencing. CyPallGlo was used to identify CYP2C19 polymorphisms in 363 patients with coronary heart disease. The univariate analysis was used to access the antiplatelet efficacy of clopidogrel in patients. The associations between CYP2C19 polymorphisms and clopidogrel efficacy were analyzed. Using CyPAllGlo to detect CYP2C19*2 and CYP2C19*3 alleles was highly specific and fast. The detection limit was approximately 0.07 µg/µl and 0.7 µg/µl for CYP2C19*2 and CYP2C19*3, respectively. The consistency between FISH and CyPAllGlo were 98.07% for CYP2C19*2 and 99.17% for CYP2C19*3. DNA sequencing showed that the accuracy of CyPAllGlo was 100%. The analysis time for the whole CyPAllGlo procedure was approximately 60 min. Univariate analysis showed that the anticoagulation efficacy of clopidogrel was related to patient age, CYP2C19 genotype, metabolic phenotype, and LDL level. The logistic regression analysis showed that the genotype of CYP2C19 and metabolic phenotype was the two risk factors for clopidogrel antiplatelet ineffectiveness. This novel CyPAllGlo is a rapid and accurate method for detection of CYP2C19 SNP. The specificity and consistency of CyPAllGlo are comparable with that of widely used DNA sequencing. These findings provide valuable rapid method for predicting clopidogrel efficacy, which can be quickly translated to improve personalized precision medicine for coronary heart disease treatment.

Association of ABCC2 polymorphism with clopidogrel response in Chinese patients undergoing percutaneous coronary intervention

Aim: In this study, we investigated the association between ABCC2 polymorphism and clopidogrel response as well as the associated hypothetical mechanism.

Methods: Chinese patients (213) with coronary artery disease (CAD) who underwent percutaneous coronary intervention (PCI) and received clopidogrel were recruited. Thereafter, their ADP-induced platelet inhibition rates (PAIR%) were determined via thromboelastometry. Further, the single-nucleotide polymorphisms (SNPs) of ABCC2 were genotyped using high-resolution melting curve (HRM)-PCR, while CYP2C19*2 and *3 polymorphisms were genotyped via real-time PCR.

Results: The allele frequencies of ABCC2 rs717620 were 74.88 and 25.12% for the C and T alleles, respectively. Further, ABCC2 rs717620 TT carriers exhibited significantly higher PAIR% values (72.60 ± 27.69) than both CT (61.44 ± 23.65) and CC carriers (52.72 ± 21.99) (p = 0.047 and p = 0.001, respectively), and ABCC2 rs717620 CT carriers showed significantly higher mean PAIR% values than ABCC2 rs717620 CC carriers (p = 0.011). However, the PAIR% values corresponding to ABCC2 rs2273697 and ABCC2 rs3740066 carriers were not different. Additionally, CYP2C19*2 AA carriers presented significantly lower PAIR% values than CYP2C19*2 GA (p = 0.015) and GG (p = 0.003) carriers, and CYP2C19*3 GA carriers also presented significantly lower PAIR% values than CYP2C19*3 GG carriers (p = 0.041). In patients with CYP2C19 extensive metabolizers (EM), ABCC2 rs717620 TT carriers showed significantly higher PAIR% values (89.77 ± 9.73) than CT (76.76 ± 26.00) and CC carriers (74.09 ± 25.29) (p = 0.040 and p = 0.009, respectively). In patients with CYP2C19 poor metabolizers (PM), ABCC2 rs717620 CC carriers showed significantly lower PAIR% values (51.72 ± 25.78) than CT carriers (75.37 ± 23.57) (p = 0.043). Furthermore, after adjusting for confounding factors, ABCC2 rs717620 was identified as a strong predictor of clopidogrel hyperreactivity.

Conclusion: We proposed a new target, ABCC2 rs717620, in the efflux pathway that affects individual responses to clopidogrel. The TT allele of ABCC2 rs717620 was also identified as an independent risk factor for clopidogrel hyperreactivity, and CYP2C19*2 and *3 showed association with an increased risk for clopidogrel resistance. Additionally, ABCC2 rs717620 may affect individual responses to clopidogrel via post-transcriptional regulation and interaction with CYP2C19. These findings provide new insights that may guide the accurate use of clopidogrel.

Antithrombotic Therapy in Patients with Atrial Fibrillation and Acute Coronary Syndrome

Acute coronary syndrome and atrial fibrillation are both common and can occur in the same patient. Combination therapy with dual antiplatelet therapy and oral anticoagulation increases risk of bleeding. Where the two conditions coexist, careful consideration is needed to determine the optimal antithrombotic treatment to reduce the risks of future ischaemic events associated with both conditions. Choices can be made in intraprocedural anticoagulation, type and dosing of oral anticoagulant, duration of combination therapy, and selection of P2Y12 inhibitor including genetic testing. This review article provides an overview of the available evidence to support clinicians in finding the delicate balance between antithrombotic efficacy and bleeding risk in patients with acute coronary syndrome and atrial fibrillation.