Differential Impact of Cytochrome 2C19 Allelic Variants on Three Different Platelet Function Tests in Clopidogrel-Treated Patients

On-treatment platelet reactivity in clopidogrel-treated patients can be measured with several platelet function tests (PFTs). However, the agreement between different PFTs is only slight to moderate. Polymorphisms of the CYP2C19 gene have an impact on the metabolization of clopidogrel and, thereby, have an impact on on-treatment platelet reactivity. The aim of the current study is to evaluate the differential effects of the CYP2C19 genotype on three different PFTs. Methods: From a prospective cohort study, we included patients treated with clopidogrel following percutaneous coronary intervention (PCI). One month after PCI, we simultaneously performed three different PFTs; light transmission aggregometry (LTA), VerifyNow P2Y12, and Multiplate. In whole EDTA blood, genotyping of the CYP2C19 polymorphisms was performed. Results: We included 308 patients treated with clopidogrel in combination with aspirin (69.5%) and/or anticoagulants (33.8%) and, based on CYP2C19 genotyping, classified them as either extensive (36.4%), rapid (34.7%), intermediate (26.0%), or poor metabolizers (2.9%). On-treatment platelet reactivity as measured by LTA and VerifyNow is significantly affected by CYP2C19 metabolizer status (p < 0.01); as metabolizer status changes from rapid, via extensive and intermediate, to poor, the mean platelet reactivity increases accordingly (p < 0.01). On the contrary, for Multiplate, no such ordering of metabolizer groups was found (p = 0.10). Conclusions: For VerifyNow and LTA, the on-treatment platelet reactivity in clopidogrel-treated patients correlates well with the underlying CYP2C19 polymorphism. For Multiplate, no major effect of genetic background could be shown, and effects of other (patient-related) variables prevail. Thus, besides differences in test principles and the influence of patient-related factors, the disagreement between PFTs is partly explained by differential effects of the CYP2C19 genotype.

The effect of CYP2C19 gene polymorphism on the eradication rate of Helicobacter pylori by proton pump inhibitors-containing regimens in Asian populations: a meta-analysis

Premise: The effects of proton pump inhibitors (PPI) depend on metabolic enzyme CYP2C19 that has different activity due to gene polymorphism. The purpose of this meta-analysis is to determine the potential effects of CYP2C19 polymorphism on the efficiency of PPI-based treatment. Materials & methods: The PubMed, EMBASE, Cochrane Library, etc. were searched for relevant articles published in English or Chinese from inception to 31 May 2020. Finally, 26 randomized controlled trials and 15 cohort studies met the inclusion criteria and used for the meta-analysis via STATA version 15. Results: Poor metabolizer (PM) genotype Helicobacter pylori eradication rates were highest for Asian individuals receiving triple or quadruple first-line therapy based on PPIs (p < 0.05). CYP2C19 polymorphism could influence H. pylori eradication rate only in Mainland China and Japan (p < 0.05). Conclusion: PM genotype facilitates the elimination of H. pylori in Asian populations. Rabeprazole-, esomeprazole- and pantoprazole-based eradication program was less affected by the CYP2C19 polymorphism.

Impact of Total Protein Level and Dysglycaemia on the Efficacy of Clopidogrel in Patients Underwent Carotid Artery Stenosis with CYP2C19 Genetic Variants

BACKGROUND: CYP2C19polymorphisms are associated with the increased risk of major adverse cardiovascular/cerebrovascular events (MACCEs) in cerebral intervention. In this study, we wanted to investigate whether the CYP2C19 polymorphism and other nongenetic factors can influence the incidence of MACCEs in cerebral artery stenosis disease patients.METHODS: A total of 164 patients underwent cerebral artery stenting and 138 patients underwent conservative treatment among 1406 who patients underwent CYP2C19 gene screening and were enrolled in this study. A Cox proportional hazards model and Kaplan–Meier analyses were used to assess the predictive value of CYP2C19 loss-of-function (LOF) allele (*2, *3) carrier status and other risk factors.RESULTS: The CYP2C19 *1/*1 genotype was observed to be the most predominant among the patients (41.96%). The patients who underwent conservative treatment and had glucose levels> 6.5 mmol/L were more likely to experience MACCEs (p = 0.022). CYP2C19 LOF allele variants (p = 0.032), total protein < 65 g/L (p = 0.017) and glucose > 6.5 mmol/L (p = 0.028) were associated with an increased risk of MACCEs in patients who underwent cerebral artery stents in the multivariable Cox analysis.CONCLUSION: CYP2C19 polymorphisms, total protein levels and glucose can impact the risk of MACCEs in patients who undergo cerebral artery stents.

A meta-analysis of effects of CYP2C9 and CYP2C19 polymorphisms on phenytoin pharmacokinetic parameters

Aim: Phenytoin is metabolized through CYP2C9 and CYP2C19 . Polymorphisms of CYP2C9 and CYP2C19 may increase plasma concentration and side effects. Materials & methods: Systematic review and meta-analysis were performed to evaluate the effects of CYP2C9 and CYP2C19 polymorphism on pharmacokinetic parameters. PubMed, Science Direct, Cochrane library, and Thai databases were systematically searched. Results: Eight observational studies, comprising a total of 633 patients were included. Michaelis–Menten constant was significantly higher in the polymorphism of CYP2C9IM/CYP2C19EM and CYP2C9IM/CYP2C19IM groups as compared with the control groups (CYP2C9EM/CYP2C19EM) at 2.16 and 1.55 mg/l (p < 0.00001, p < 0.0001). The maximum rate of action was significantly lower in the control groups as compared with the polymorphism of CYP2C9IM/CYP2C19EM and CYP2C9IM/CYP2C19IM groups at 3.10 and 3.53 mg/kg/day (p = 0.00001, <0.0001). Conclusion: The dosage regimen for patients in the CYP2C9IM group to achieve phenytoin therapeutic levels was 2.1–3.4 mg/kg/day.

PHARMACOGENETIC BASES OF INDIVIDUAL SENSITIVITY AND PERSONALIZED ADMINISTRATION OF ANTIPLATELET THERAPY IN DIFFERENT ETHNIC GROUPS

Cardiovascular diseases (CVDs) are the leading cause of disability and mortality worldwide. Increased thrombosis is the trigger point for the development of various CVDs and their complications, and therefore, therapy with P2Y12-receptor inhibitors is always pathogenetically justified and vital. However, according to the various data, 10-25% of patients treated with clopidogrel have “resistance” to antiplatelet therapy. The causes for the formation of resistance are still not clear. There is no generally accepted, standard methodology for determining resistance to antiplatelet agents. In addition, there are no methodological approaches to identify the patients with resistance to antiplatelet drugs, and standardized schemes for correcting a low sensitivity to these drugs.The aim of this review was to summarize the available results of foreign and domestic studies devoted to the investigation of the effectiveness and safety problems of antiplatelet drugs administration from the point of view of the genetic predisposition to changes in their metabolism.Materials and methods. For the review, the following information from scientific literature represented in open and accessible sources for the period of 1996-2020, was used: pharmgkb.org, PubMed, Scopus, Web of Science Core Collection, Elibrary. Search queries – “Genetic features+antiplatelet therapy+ethnic groups”, “CYP2C19+clopidogrel+antiplatelet therapy effectiveness”; “Stent retrombosis+CYP2C19 polymorphism+ residual platelet reactivity” and “CYP2C19 polymorphism+ethnic groups+clopidogrel resistance” in both Russian and English equivalents. All these data are placed in electronic databases.Results. Currently, the problem of the resistance formation to antiplatelet drugs is studied insufficiently. The best thought-out issue is the research of the effect of the polymorphic alleles carriage of the CYP2C19 gene on the residual platelet reactivity in the patients administrated with dual antiplatelet treatment, including clopidogrel. In general, the analysis of open literature sources indicates the presence of a statistically significant association between the carrier of slow alleles of the CYP2C19 gene and the residual platelet reactivity, clinically manifested by thrombosis and adverse cardiovascular events. The occurrence frequency of polymorphic carriage of the CYP2C19 gene varies in different ethnic groups, so it cannot be extrapolated to individual subjects, peculiar in the ethnic diversity.Conclusion. To develop preventive and predictive measures aimed at overcoming resistance to antiplatelet agents, as well as working out methodological approaches to personalized prescribtion of this group drugs, a further investigation with the expansion of the search for causes and the study of the other genes participation of the cytochrome P450 system, is required.

Effects of CYP2C19 Polymorphism on Metabolism and Effectiveness of Proton Pump Inhibitors: A Review of Clinical and Laboratory Studies

Introduction: Establishing the reasons for the decrease in the effectiveness of anti-Helicobacter pylori therapy and proton pump inhibitors in the treatment of acid-dependent diseases is an urgent task due to high prevalence of these disorders undermining population health. Our objective was to conduct a literature review to assess the influence of the genetic polymorphism of cytochrome P-450 CYP2C19 on the eradication rate of Helicobacter pylori and the metabolism of proton pump inhibitors, to evaluate the effectiveness of their use, and to determine possible ways of overcoming refractoriness to these drugs in the clinic. Materials and methods: We analyzed published studies found in domestic (eLibrary, CyberLeninka.ru) and international (PubMed, Cochrane Library) databases. Results: We revealed a genetic polymorphism CYP2C19 of cytochrome P-450, according to which different types of drug metabolism were identified: fast, intermediate, slow, and ultrafast. The relationship of this polymorphism with biotransformation of proton pump inhibitors was then analyzed. In Russia, the predominance of fast and intermediate metabolism in individuals of the Caucasian race decreases the efficacy of acid-suppressive therapy and the Helicobacter pylori eradication rate. Correction of the daily dose and frequency of drug administration are necessary to increase the antisecretory effect of proton pump inhibitors. Discussion: The dependence of proton pump inhibitor biotransformation on the CYP2C19 polymorphism determines the differences between patients with different types of metabolism in the effectiveness of these drugs, the success of anti-Helicobacter pylori treatment, and clinical outcomes. Pharmacogenetic testing is useful for predicting the response to proton pump inhibitors, the likelihood of developing adverse events, and the possibility of personalized prescriptions in patients with acid-related diseases. Conclusion: Genetic testing of cytochrome CYP2C19 helps optimize the use of proton pump inhibitors, overcome refractoriness, and improve the quality of treatment of acid-dependent diseases and the overall Helicobacter pylori eradication rate.

Prevalence of CYP2C19 polymorphism in Bogotá, Colombia: The first report of allele *17

Introduction Proton pump inhibitors (PPIs) are a group of drugs that are essential for the treatment of acid-related disorders, such as gastroesophageal reflux (GERD), dyspepsia, gastric ulcers and Helicobacter pylori (H. pylori) infection. PPIs such as omeprazole, esomeprazole, pantoprazole and lansoprazole are metabolized by the CYP2C19 enzyme, which is encoded by a polymorphic gene. Four polymorphisms have an impact on the speed of PPI metabolism: CYP2C19*1/*1 (extensive metabolizers), CYP2C19*2/*2 (intermediate metabolizers), CYP2C19*3/*3 (poor metabolizers) and CYP2C19*17/*17 (ultrarapid metabolizers). Extensive and ultrarapid metabolizers inactivate PPIs quickly, which consequently causes low plasma concentrations of PPIs, while intermediate or poor metabolizers have higher plasma concentrations of PPIs and, therefore, PPIs have greater therapeutic efficacy in individuals with these polymorphisms. Objective To determine the frequency of genetic polymorphisms of the CPY2C19 enzyme in Bogotá, Colombia. Methods This observational study was conducted in Bogotá between 2012 and 2015 and was part of a clinical trial (ID: NCT03650543). It included 239 subjects with dyspepsia, H. pylori infection, or GERD symptoms. CYP2C19 genotyping was performed on gastric biopsy samples. Polymorphisms *1, *2, and *3 were analyzed by real-time PCR (Roche®), and PCR-RFLP was used to determine the presence of polymorphism *17. Results The distribution of different types of PPI metabolizers was as follows: extensive (70.7%), ultrarapid (12.9%), intermediate (8.8%) and poor (0.8%). Conclusion The population studied consisted mainly of extensive and ultrarapid PPI metabolizers. These findings show that it is necessary to increase PPI doses in this group of subjects or to use PPIs that are not metabolized by CYP2C19 (rabeprazole). This is the first Colombian work to identify ultrarapid metabolizers.