Clustering of ABCB1 and CYP2C19 Genetic Variants Predicts Risk of Major Bleeding and Thrombotic Events in Elderly Patients with Acute Coronary Syndrome Receiving Dual Antiplatelet Therapy with Aspirin and Clopidogrel

miR-6076 rs1463411 polymorphisms are associated with bleeding during clopidogrel treatment in patients with acute coronary syndrome

Bleeding is a major adverse event during clopidogrel treatment in patients with acute coronary syndrome (ACS). However, the potential mechanism affecting bleeding among individuals is unclear. Herein, we investigated the involvement of CYP2C19*2 and CYP2C19*3, as well as 10 miRNA polymorphisms, in bleeding in Chinese patients with ACS during the first year of clopidogrel treatment. The miR-6076 rs1463411 G polymorphism was significantly associated with the risk of bleeding (P < 0.001), and the rs1463411 GT + GG genotype significantly increased the risk of bleeding (adjusted odds ratio, 6.09; 95% confidence interval, 1.09-34.0; P < 0.001). Dual luciferase assay showed that miR-6076 significantly decreased the mRNA expression of P2RY12 (P < 0.05). P2RY12 mRNA and protein levels were significantly lower in cells transfected with miR-6076-G than in cells transfected with miR-6076-T (P < 0.05). The findings indicate that miR-6076 targets P2RY12 mRNA and that miR-6076 rs1463411 T/G polymorphisms differentially regulate P2RY12 mRNA and protein levels in cells. rs1463411 G polymorphism may increase the risk of bleeding during clopidogrel treatment in patients with ACS.

Dosage optimization of clopidogrel via a precision medicine approach: the way forward

Clopidogrel is a prodrug chiefly metabolized by the hepatic isoenzyme CYP2C19 to its active metabolite that inhibits the platelet aggregation. It has been proven in many populations that the genetic polymorphism of CYP2C19 has influence on the pharmacokinetic and or pharmacodynamics of this drug and resulting in high inter-individual variability in the treatment outcomes. As CYP2C19 genetic polymorphism is highly prevalent among the Asian population, the influence of the same on the pharmacokinetics and; thereby, the pharmacodynamics of clopidogrel needs more attention. Using the pharmacogenetic information for drug therapy could help overcome these issues and to optimize the dosage regimen of clopidogrel, this review advocates the precision medicine approach for reducing the clopidogrel resistance and adverse cardiovascular events.

Impact of genetic variants on major bleeding after percutaneous coronary intervention based on a prospective multicenter registry

Although dual antiplatelet therapy is essential for patients who undergo percutaneous coronary interventions, the risk of bleeding remains an unsolved problem, and there is limited information on the potential relationship between genetic variants and major bleeding. We analyzed the correlations between four major single nucleotide polymorphisms (CYP2C19, ABCB1, PON1, and P2Y12 G52T polymorphisms) and clinical outcomes in 4489 patients from a prospective multicenter registry. The primary endpoint was major bleeding, defined as a Bleeding Academic Research Consortium ≥ 3 bleeding event. The allelic frequencies of ABCB1, PON1, and both individual and combined CYP2C19 variants did not differ significantly between patient groups with and without major bleeding. However, the allelic frequency of the P2Y12 variant differed significantly between the two groups. Focusing on the P2Y12 G52T variant, patients in the TT group had a significantly higher rate of major bleeding (6.4%; adjusted hazard ratio [HR] 2.51; 95% confidence interval [CI] 1.08-5.84; p = 0.033) than patients in the other groups (GG [2.9%] or GT [1.9%]). Therefore, the TT variant of the P2Y12 G52T polymorphism may be an independent predictor of major bleeding.Trial registration: NCT02707445 ( https://clinicaltrials.gov/ct2/show/NCT02707445?term=02707445&draw=2&rank=1 ).

The need of a multicomponent guiding approach to personalize clopidogrel treatment

Patients bearing polymorphisms termed CYP2C19 loss of function (LoF) alleles and ABCB1-C3435T may do not properly respond to standard dosage of clopidogrel and have an increased risk of thrombosis. Moreover, co-administration of proton pump inhibitors (PPIs) and clopidogrel may attenuate the antiplatelet effect. The role of pharmacogenetics and PPIs/clopidogrel drug-drug interaction has been extensively investigated in patients with acute coronary syndrome after stent implantation (ACS/PCI), while data in patients undergoing vascular surgery are scarce. Here we have performed a systematic review to evaluate the available literature in such a clinical setting and have discussed the controversies about the use of CYP2C19 pharmacogenetics and platelet function testing to personalize clopidogrel treatment. In addition, we have made a comparison of the literature data with our findings concerning patients eligible for vascular surgery and treated with clopidogrel, in whom we used a combined management based on the CYP2C19 and ABCB1 pharmacogenetic testing with monitoring of therapeutic adherence and PPIs-clopidogrel interaction. Both our data and those produced during both observational studies and randomized clinical trials confirm the validity of pharmacogenetics to personalize clopidogrel treatment and stress the importance to make a drug monitoring considering all the known variables, potentially responsible for treatment failure. However, the American Heart Association and the European Cardiovascular Society recommend against the routine use of clopidogrel pharmacogenetic testing. An update of the international guidelines on antiplatelet therapy, incorporating the evidence related to CYP2C19 pharmacogenetics and PPIs-clopidogrel drug-drug interactions is warranted both in ACS/PCI patients and subjects undergoing vascular surgery.

Increased Risk of Clopidogrel-Induced Gastric Mucosal Erosion in Elderly Chinese Men Harboring the ABCB1 3435T Allele

Background

It is uncertain whether long-term use of clopidogrel alone can cause gastric mucosal injury. This study aimed to evaluate the relationship between ABCB1 C3435T polymorphisms, which could affect the intestinal absorption of clopidogrel, and gastric mucosal erosion in elderly Chinese men who used clopidogrel alone.

Methods

We selected 298 male patients (aged between 68.2 and 89.5 years, average age 78); 201 of them constituted the control group, and 97 constituted the case group. Patients taking clopidogrel alone who had undergone endoscopic screening for gastric erosion were analyzed for ABCB1 C3435T polymorphisms by a TaqMan assay.

Results

The proportion of people carrying the ABCB1 3435T allele (n = 63, 64.9% vs n = 97, 48.3%, p = 0.007) was significantly higher in the case group than in the control group. After adjustments for significant factors were made, ABCB1 3435T allele carrier (OR 2.14, 95% CI 1.43–3.84, p <0.01) was found to be associated with gastric mucosal erosion in people who used clopidogrel alone.

Conclusion

Carrying the ABCB1 3435T allele may be a useful genetic predictor for clopidogrel-induced gastric mucosal erosion in elderly Chinese men.

Distribution of CYP2C19, ABCB1 and PON1 polymorphisms in Chinese Han, Hui, Uygur and Kazak patients with coronary atherosclerotic heart disease

CYP2C19, ABCB1 and PON1 polymorphisms involve in the metabolism and absorption of clopidogrel, which may be associated with interethnic variability of clopidogrel response. In our study, we evaluated the prevalence of CYP2C19, ABCB1 and PON1 single nucleotide polymorphisms (SNP) in patients with coronary atherosclerotic heart disease (CHD) of Chinese Han, Hui, Uygur and Kazak ethnic groups. Five SNPs were detected [CYP2C19 ∗2 (rs4244285), CYP2C19 ∗3 (rs4986893), CYP2C19 ∗17 (rs12248560), ABCB1 (rs1045642) and PON1 (rs662)]. The analysis was performed in 1,337 patients with CHD, including 831 Han, 85 Hui, 352 Uygur and 69 Kazak. The results revealed the differential distribution of the five SNPs. Frequencies of CYP2C19 no function variants in Uygur and Kazak were lower than those in Han and Hui groups (P < .05). CYP2C19 variants with increased function were more common in Uygur (13.6%) and Kazak (10.9%) groups (P < .05). Compared with Han and Hui groups, distribution of ABCB1 allele T was more prevalent in Uygur and Kazak groups (53.8% and 50.7%, respectively, P < .05). PON1 allele A frequencies of 55.7% and 58.7% in Uygur and Kazak showed higher prevalence than in the Han (38.4%) and Hui (43.5%) groups (P < .05). In conclusion, CYP2C19 *2 and *3 alleles are prevalent in Chinese Han and Hui groups, whereas CYP2C19 *17, ABCB1 T and PON1 A variants are relatively frequent in Chinese Uygur and Kazak ethnic groups. Our findings may provide a theoretical basis for the explanation of ethnic differences in determining clinical therapy strategies and predicting adverse effects.

Sexual Dimorphism in Drug Metabolism and Pharmacokinetics

Background:

Sex and gender-based differences are observed well beyond the sex organs and affect several physiological and biochemical processes involved in the metabolism of drug molecules. It is essential to understand not only the sex and gender-based differences in the metabolism of the drug but also the molecular mechanisms involved in the regulation of drug metabolism for avoiding sex-related adverse effects of drugs in the human.

Method:

The articles on the sex and gender-based differences in the metabolism of drug molecules were retrieved from the Pub Med database. The articles were classified into the metabolism of the drug molecule, gene expression regulation of drug-metabolizing enzymes, the effect of sex hormones on the metabolism of drug, expression of drugmetabolizing enzymes, etc.

Result:

Several drug molecules are known, which are metabolized differently in males and females. These differences in metabolism may be due to the genomic and non-genomic action of sex hormones. Several other drug molecules still require further evaluation at the molecular level regarding the sex and gender-based differences in their metabolism. Attention is also required at the effect of signaling cascades associated with the metabolism of drug molecules.

Conclusion:

Sex and gender-based differences in the metabolism of drugs exist at various levels and it may be due to the genomic and non-genomic action of sex hormones. Detailed understanding of the effect of sex and related condition on the metabolism of drug molecules will help clinicians to determine the effective therapeutic doses of drugs dependingon the condition of patient and disease.