Genetic and Nongenetic Factors Affecting Clopidogrel Response in the Egyptian Population

Genetic polymorphisms of CYP2C19 in ecuadorian population: An interethnic approach

Introduction

CYP2C19 is a highly polymorphic gene responsible for metabolizing commonly used drugs. CYP2C19*2,*3 (loss of activity alleles) and *17 (increased activity allele) are the principal alleles included in clinical guidelines, however their prevalence varies among different ethnicities. Ecuadorian population is formed by Mestizos, Afrodescendants and Native Americans and frequency of CYP2C19 alleles could be different among them. The objective of this study was to establish the frequency of these variants in the different populations of Ecuador and to compare them with other populations.

Materials and methods

DNA from 105 Afrodescendants, 75 Native Americans of the Kichwa ethnicity, and 33 Mestizos Ecuadorians was analyzed by nested-PCR to identify CYP2C19*17 carriers. CYP2C19*2 allele was analyzed in DNA from 78 Afrodescendants, 29 Native Americans of the Kichwa, and 16 Mestizos by TaqMan Allelic Discrimination Assay. CYP2C19*3 was analyzed in 33 Afrodescendants by nested-PCR.

Results

The global frequencies of the alternate alleles were 14.22% (CYP2C19*2) and 2.10% (CYP2C19*17). No differences (p > 0.05) were observed among the subgroups. No CYP2C19*3 carrier was identified. CYP2C19*2 frequencies in Ecuador were similar to the ones reported in Europe, Africa and Middle East countries and to some American populations. Low CYP2C19*17 frequencies, like the ones in our population, were also observed in East and South Asia and in Native American groups.

Discussion

Absence of differences in the ethnic groups in Ecuador for CYP2C19*2 and *17 could be due to either a bias in sample selection (ethnic group was assed by self-identification) or to a high interethnic admixture in the Ecuadorian population that would had diluted genetic differences. In addition, CYP2C19*2, *3, and *17 alleles frequencies in our study suggest that Ecuadorians ancestry is mostly of Native American origin.

Advances and Perspectives in methods for identifying high platelet reactivity

Antiplatelet therapy is the foundational treatment for the prevention and treatment of coronary and cerebrovascular ischemic events in patients with coronary heart disease, ischemic stroke, and transient ischemic attack (TIA). However, with more and more studies reporting an increased risk of thrombosis in some patients due to poor response to therapeutic agents, the selection of appropriate P2Y12 inhibitors has become a major challenge that needs to be addressed urgently. Currently, commonly used oral P2Y12 inhibitors include clopidogrel, ticagrelor, and prasugrel. Assessing patients' risk factors before the development of treatment regimens by effectively predicting the risk of high platelet reactivity with specific P2Y12 inhibitors in advance to avert the occurrence of major adverse cardiovascular and cerebrovascular events (MACCE) is the key point to the problem. Up to now, methods available for predicting platelet reactivity include genetic testing, platelet function testing, and risk scores. This review provides a summarization of the existent available identification methods and analyzes the advantages and drawbacks of different methods in specific clinical settings, intending to guide the rational clinical application of P2Y12 receptor inhibitors.

CYP2C19 *2/*2 Genotype is a Risk Factor for Multi-Site Arteriosclerosis: A Hospital-Based Cohort Study

Background

Vascular diseases such as atherosclerosis usually affect multiple organs. Genetic factors have a certain proportion in the risk factors of atherosclerosis. The purpose was to investigate the relationship of cytochrome P450 2C19 (CYP2C19) polymorphisms with multi-site atherosclerosis.

Methods

The study included 410 patients with single-site atherosclerosis and 529 patients with multi-site atherosclerosis. The relationship between CYP2C19 rs4244285 and rs4986893 polymorphisms and single-site atherosclerosis and multi-site atherosclerosis was analyzed.

Results

The proportion of CYP2C19 rs4244285 A allele (35.9% vs 29.9%, P=0.007) and rs4986893 G allele (97.7% vs 94.8%, P=0.001) in multi-site atherosclerosis group was significantly higher than that in single-site atherosclerosis group. The distribution of CYP2C19 genotypes was significantly different between the two groups (P=0.002). The results of univariate logistic regression indicated that CYP2C19 *1/*3 genotype (*1/*3 vs *1/*1: odds ratio (OR) 0.456, 95% confidence interval (CI): 0.231-0.902, P=0.024) may decrease risk of multi-site atherosclerosis, while *2/*2 genotype (*2/*2 vs *1/*1: OR 1.780, 95% CI: 1.100-2.880, P=0.019) may increase risk of multi-site atherosclerosis. Multivariate logistic regression (adjusted for gender, age, smoking, drinking, hypertension, and diabetes) indicated that CYP2C19 *1/*3 genotype (*1/*3 vs *1/*1: OR 0.459, 95% CI: 0.231-0.909, P=0.026) may be an independent protective factor for multi-site atherosclerosis, while *2/*2 genotype (*2/*2 vs *1/*1: OR 1.767, 95% CI: 1.091-2.864, P=0.021) may be an independent risk factor for multi-site atherosclerosis.

Conclusion

CYP2C19 *1/*3 genotype may be an independent protective factor for multi-site atherosclerosis, while *2/*2 genotype may be an independent risk factor for multi-site atherosclerosis.

Role of genetic polymorphisms in clopidogrel response variability: a systematic review

INTRODUCTION

Clopidogrel is a P2Y12 inhibitor that has become a mainstay treatment following percutaneous intervention with drug-eluting stent placement to decrease restenosis and its potential complications, including sudden cardiac death and ischaemic strokes in patients with significant vascular disease.

AREAS COVERED

As a prodrug, the metabolism and efficacy of clopidogrel are contingent on the presence of wild-type CYP450 (CYP2C19) alleles. Genetic polymorphisms and variants are well known to impair its ability to prevent major adverse cardiovascular events in these patients, with inadequate response rates as high as 30% in previous publications. Patterns of allelic frequencies are expected to exhibit similarities between individuals of the same ancestry, ethnic group or geographic region. Accordingly, we seek to further elucidate worldwide prevalence rates for genetic polymorphisms in the CYP2C19-dependent metabolism of clopidogrel and review the potential of personalised CYP2C19 genotyping in clinical practice to mitigate this high treatment resistance and its associated burden on patients.

EXPERTS' COMMENTARY

Our findings support the consideration of genotyping before initiation of therapy to guide adequate dosage or substitutions of other P2Y12 inhibitors to promote personalised, precision medicine and to prevent adverse events when these therapies may inevitably fail in patients with variants of the CYP450 (CYP2C19) system.

CYP2C19 Polymorphism in Ischemic Heart Disease Patients Taking Clopidogrel After Percutaneous Coronary Intervention in Egypt

BACKGROUND

Cardiovascular diseases (CVDs) are considered a leading cause of death worldwide. Allelic variation in the CYP2C19 gene leads to a dysfunctional enzyme, and patients with this loss-of-function allele will have an impaired clopidogrel metabolism, which eventually results in major adverse cardiovascular events (MACE). Ischemic heart disease patients (n = 102) who underwent percutaneous cardiac intervention (PCI) followed by clopidogrel were enrolled in the present study.

METHODS

The genetic variations in the CYP2C19 gene were identified using the TaqMan chemistry-based qPCR technique. Patients were followed up for 1 year to monitor MACE, and the correlations between the allelic variations in CYP2C19 and MACE were recorded.

RESULTS

During the follow-up, we reported 64 patients without MACE (29 with unstable angina (UA), 8 with myocadiac infarction (MI), 1 patient with non-STEMI, and 1 patient with ischemic dilated cardiomyopathy (IDC)). Genotyping of CYP2C19 in the patients who underwent PCI and were treated with clopidogrel revealed that 50 patients (49%) were normal metabolizers for clopidogrel with genotype CYP2C19*1/*1 and 52 patients (51%) were abnormal metabolizers, with genotypes CYP2C19*1/*2 (n = 15), CYP2C19*1/*3 (n = 1), CYP2C19*1/*17 (n = 35), and CYP2C19*2/*17 (n = 1). Demographic data indicated that age and residency were significantly associated with abnormal clopidogrel metabolism. Moreover, diabetes, hypertension, and cigarette smoking were significantly associated with the abnormal metabolism of clopidogrel. These data shed light on the inter-ethnic variation in metabolizing clopidogrel based on the CYP2C19 allelic distribution.

CONCLUSION

This study, along with other studies that address genotype variation of clopidogrel-metabolizing enzymes, might pave the way for further understanding of the pharmacogenetic background of CVD-related drugs.

CYP2C19 loss-of-function is associated with increased risk of hypertension in a Hakka population: a case-control study

BACKGROUND

Genetic factors have a certain proportion in the risk factors of hypertension. The purpose was to investigate the relationship of cytochrome P450 2C19 (CYP2C19) polymorphisms with hypertension in Hakka population.

METHODS

The study included 1,872 hypertensive patients and 1,110 controls. The genotypes of CYP2C19 rs4244285 and rs4986893 of all individuals were detected and analyzed.

RESULTS

The genotype and allele distributions of CYP2C19 rs4244285 were significantly different between hypertension group and control group. The CYP2C19 *1/*1 genotype was the most predominant among the subjects (40.8%), followed by the CYP2C19 *1/*2 genotype (40.5%). The percentage of CYP2C19*1, *2, and *3 allele was 64.2%, 30.8%, and 5.0%, respectively. The proportion of intermediate metabolizers (IM) (49.3% vs. 42.9%), poor metabolizers (PM) (14.3% vs. 8.9%) (P < 0.001), and CYP2C19*2 allele (33.8% vs. 25.7%, P < 0.001) in hypertension group was significantly higher than that in control group. Multivariate logistic regression (adjusted for gender, age, smoking, and drinking) indicated that CYP2C19 *1/*2, *1/*3, and *2/*2 genotypes may increase susceptibility to hypertension. And the CYP2C19 IM genotype (IM vs. EM: OR 1.514, 95% CI: 1.291-1.775, P < 0.001), PM genotype (PM vs. EM: OR 2.120, 95% CI: 1.638-2.743, P < 0.001), IM + PM genotypes (IM + PM vs. EM: OR 1.617, 95% CI: 1.390-1.882, P < 0.001) may increase risk of hypertension.

CONCLUSIONS

CYP2C19 loss-of-function (IM, PM genotypes) is independent risk factor for hypertension susceptibility. Specifically, the risk genotypes include CYP2C19 *1/*2, *1/*3, and *2/*2.

The efficacy of clopidogrel in preventing recurrent cardiovascular events among Arab population carrying different CYP2C19 mutations: systematic review and meta-analysis

Background

The prevalence and the role of CYP2C19 gene mutations concerning recurrent Cardiovascular Events (CVEs) among patients treated with clopidogrel is still controversial especially among Arab people. Therefore, this review aimed to determine the frequency of CYP2C19 polymorphic alleles among the Arab population and to investigate the efficacy of clopidogrel as an antiplatelet drug among those carrying different variants of this gene.

Methodology

Two authors independently searched in PubMed, Google Scholar, and EMBASE databases at any year for studies related to the role of CYP2C19 gene on the prognosis of patients with CVEs treated with clopidogrel. The review included Arab people who were genotyped to determine the frequency of CYP2C19 genotypes and alleles (the qualitative part). Concerning the quantitative part (meta-analysis), only patients who previously had CVEs and using clopidogrel as secondary prophylaxis had been included. The Newcastle Ottawa Scale for non-randomizes Studies was utilized to consider the risk of bias among included studies. We analyzed the data using odds ratio at 95% confidence interval and the quality of evidence of each outcome measure was judged using GRADE approach.

Results

The current study revealed that 4% of Arabs reported in the included studies are homozygous, and 25% are heterozygous for the CYP2C19*2 allele. While 3% and 18.5% of them are homozygous and heterozygous of CYP2C19*17 alleles, respectively. A significant increased risk of recurrent CVEs by about threefold was associated with CYP2C19*2 or CYP2C19*3 allele carriers (OR = 3.32, CI = 1.94–5.67, and OR = 3.53, CI = 1.17–10.63, respectively). However, no significant increased risk among carriers of CYP2C19*17 mutation (OR = 0.80, (CI = 0.44–1.44) was documented.

Conclusion

The present study revealed that Arabs carrying CYP2C19*2 and CYP2C19*3 alleles could be at increased risk of decreasing the antiplatelet efficacy of clopidogrel and an alternative drug should be prescribed for those patients to avoid recurrent CVEs. However, few available studies were included in the quantitative part of the analysis and further studies with large sample size are recommended to confirm our results.

Effect of CYP2C19 genetic variants on bleeding and major adverse cardiovascular events in a cohort of Arab patients undergoing percutaneous coronary intervention and stent implantation

INTRODUCTION

One-third of patients have clopidogrel resistance that may lead to major adverse cardiac events (MACEs). By contrast, it was found that some clopidogrel-treated patients have hyperresponsive platelets that are associated with higher bleeding risk. Several studies have shown that polymorphisms in the gene encoding the CYP2C19 contribute to the variability in response to clopidogrel. Data on genetic and nongenetic factors affecting clopidogrel response in the Arab population are scarce. In this prospective cohort study, we sought to assess the association between the increased function allele (CYP2C19*17) and bleeding events, and validate the effect of the CYP2C19 genetic variants and nongenetic factors on the incidence of MACEs.

METHODS

Blood samples were collected from patients that were undergoing percutaneous coronary intervention and receiving clopidogrel at the Heart Hospital, a specialist tertiary hospital in Doha, Qatar. Patients were followed for 12 months. Genotyping was performed for CYP2C19*2, *3, and *17 using TaqMan assays.

RESULTS

In 254 patients, the minor allele frequencies were 0.13, 0.004, and 0.21 for *2, *3, and *17, respectively. Over a 12-month follow-up period, there were 21 bleeding events (8.5 events/100 patient-year). CYP2C19*17 carriers were found to be associated with increased risk of bleeding (OR, 21.6; 95% CI, 4.8-96.8; P < 0.0001). CYP2C19*2 or *3 carriers were found to be associated with increased risk of baseline and incident MACE combined (OR, 8.4; 95% CI, 3.2-23.9; P < 0.0001).

CONCLUSION

This study showed a significant association between CYP2C19*17 allele and the increased risk of bleeding, and CYP2C19*2 or *3 with MACE outcomes.

Impact of TNF-α Gene Polymorphisms on Pancreatic and Non-Small Cell Lung Cancer-Induced Cachexia in Adult Egyptian Patients: A Focus on Pathogenic Trajectories

Background

Cachexia is a frequent syndrome in pancreatic and non-small cell lung (NSCL) cancer patients. The storm of cancer-induced inflammatory cytokines, in particular TNF-α, is a crucial pathogenic mechanism. Among the molecular alterations accused of cancer-induced cachexia, TNF-α 308 G/A (rs1800629) and −1031T/C (rs1799964) are single-nucleotide polymorphisms (SNPs) within the gene encoding this pro-inflammatory cytokine. Recent studies have demonstrated the crucial role of non-coding microRNAs (miRNAs) in pathogenesis of different diseases including cachexia. Moreover, the mechanistic cytokine signaling pathway of miR-155, as a TNF-α regulator, supports the involvement of SOCS1, TAB2, and Foxp3, which are direct targets of TNF-α gene.

Aim

A case–control study (NCT04131478) was conducted primarily to determine the incidence of TNF-α 308 G/A (rs1800629) and −1031T/C (rs1799964) gene polymorphisms in adult Egyptian patients with local/advanced or metastatic pancreatic or NSCL cancer and investigate both as cachexia risk factors. The association of gene polymorphism with cachexia severity and the expression of miR-155 in cachectic patients were analyzed. A mechanistic investigation of the cytokine signaling pathway, involving SOCS1, TAB2, and Foxp3, was also performed.

Results

In both pancreatic and NSCL cancer cohorts, the mutant TNF-α variant of 308 G/A was positively associated with cachexia; on the contrary, that of 1031T/C was negatively associated with cachexia in the NSCL cancer patients. MiR-155 was higher in cachexia and in alignment with its severity in the cachectic group as compared with the non-cachectic group in both the pancreatic and NSCL cancer patients. Though TAB2 did not change to any significant extent in cachectic patients, the levels of SOCS1 and Foxp3 were significantly lower in the cachectic group as compared with the non-cachectic group.

Conclusion

Carriers of the A allele 308 G/A gene and high miR-155 are at greater risk of cachexia in both the pancreatic and NSCL cancer patients; however, the mutant variant of 1031T/C gene is protective against cachexia in the NSCL cancer patients. Finally, high levels of miR-155 in the cachectic group lead to negative feedback inhibition of both SOCS1 and Foxp3 in both the pancreatic and NSCL cancer patients.

Polymorphisms of genes related to phase II metabolism and resistance to clopidogrel

Clopidogrel is an antiplatelet drug commonly used to prevent coagulation. This review aimed to investigate the effect of polymorphisms of G6PD, GCLC, GCLM, GSS, GST, GSR, HK and GLRX genes on clopidogrel during phase II metabolism through exploring previous studies. The results revealed that low glutathione plasma levels caused by several alleles related to these genes could affect the bioactivation process of the clopidogrel prodrug, making it unable to inhibit platelet aggregation perfectly and thus leading to severe consequences in patients with a high risk of blood coagulation. However, the study recommends platelet reactivity tests to predict clopidogrel efficacy rather than studying gene mutations, as most of these mutations are rare and other nongenetic factors could affect the drug's efficacy.

Prevalence of CYP2C19 and ITGB3 polymorphisms among Bangladeshi patients who underwent percutaneous coronary intervention

INTRODUCTION

Antithrombotic agents are the basic therapeutic option for patients with arterial thrombosis who underwent percutaneous coronary intervention (PCI). In Bangladesh, aspirin and clopidogrel are frequently prescribed as antithrombotics or platelet inhibitors. Studies reported the genetic polymorphisms of CYP2C19*2, CYP2C19*17, and ITGB3 cause an alteration of the pharmacodynamic and pharmacokinetic profile of aspirin and clopidogrel. Therefore, we aimed to assess the prevalence of CYP2C19*2, CYP2C19*17, and ITGB3 polymorphisms among Bangladeshi patients with cardiovascular disease (CVD) who underwent PCI.

METHODS

Here we assessed a total of 1,000 CVD patients (male 782 and female 218) who underwent PCI and were treated with clopidogrel and/or aspirin. We performed genotyping of patients treated with clopidogrel and aspirin by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and tetra-primer amplification refractory mutation system PCR (T-ARMS-PCR) methods. The PCR products of clopidogrel-treated patients were screened with agarose gel electrophoresis and then digested with SmaI and NsiI-HF for CYP2C19*2 and CYP2C19*17, respectively. We genotyped aspirin-treated patients with T-ARMS-PCR for missense rs5918 (PlA1/A1) polymorphism of the ITGB3 gene. Then we ran the digested PCR products on 2% agarose gel electrophoresis to detect the mentioned polymorphisms.

RESULTS

Among the clopidogrel-treated patients, we observed 64.1% polymorphism (hetero + mutant) of CYP2C19*2 (loss-of-function allele) and 22.7% (hetero + mutant) of CYP2C19*17 (gain-of-function allele). On the other hand, among the aspirin-treated patients, polymorphisms of ITGB3 were 84.1% homozygous (PlA1/A1), 15.6% heterozygous (PlA1/A2), and 0.3% mutant homozygous.

CONCLUSION

In the present study, we observed a high prevalence of genetic polymorphisms of CYP2C19 and ITGB3 genes. Therefore, we recommend genotyping of CVD patients before prescribing clopidogrel or aspirin to prevent coagulation. Based on the genotyping study, the adjustment of doses or alternative generics might require to avoid therapeutic failure or toxicity in some cases.

The Effect of CYP2C19 and Nongenetic Factors on Clopidogrel Responsiveness in the MENA Region: A Systematic Review

Clopidogrel is the cornerstone antiplatelet used in the treatment and prevention of thrombotic events. Some studies examined the effect of CYP2C19 polymorphism and nongenetic factors on clopidogrel response in the Middle East and North Africa (MENA) region. However, the consistency among these studies is yet unknown. This study aims to estimate the prevalence of CYP2C19 genetic variants in MENA region and to evaluate the effect of these variants as well as the nongenetic factors on clopidogrel responsiveness. A systematic literature search was performed to identify relevant articles. Only observational studies were included. A total of 20 studies in 8 different populations were included. The CYP2C19*2 variant is the most prevalent loss-of-function (LOF) allele in the MENA region (1.7%-35%). The frequency of CYP2C19*17 ranged from 5.3% to 26.9%. Of the 9 studies, 6 found an association between carriers of at least 1 LOF allele and clopidogrel resistance. Older age, high body mass index, females, and the use of calcium channel blockers were associated with clopidogrel resistance as well. Association between the CYP2C19*2 allele and clopidogrel resistance is common among MENA populations. Future studies should focus on having larger sample sizes to detect other minor variant alleles and their effect on bleeding and cardiovascular outcomes.

A review of clinical pharmacogenetics Studies in African populations

Effective interventions and treatments for complex diseases have been implemented globally, however, coverage in Africa has been comparatively lower due to lack of capacity, clinical applicability and knowledge on the genetic contribution to disease and treatment. Currently, there is a scarcity of genetic data on African populations, which have enormous genetic diversity. Pharmacogenomics studies have the potential to revolutionise treatment of diseases, therefore, African populations are likely to benefit from these approaches to identify likely responders, reduce adverse side effects and optimise drug dosing. This review discusses clinical pharmacogenetics studies conducted in African populations, focusing on studies that examined drug response in complex diseases relevant to healthcare. Several pharmacogenetics associations have emerged from African studies, as have gaps in knowledge.

Effect of Genetic and Nongenetic Factors on the Clinical Response to Mineralocorticoid Receptor Antagonist Therapy in Egyptians with Heart Failure

This prospective cohort study evaluated the association between the renin angiotensin aldosterone system genotypes and response to spironolactone in 155 Egyptian patients with heart failure with reduced ejection fraction (HFrEF). Genotype frequencies for AGT rs699 were: CC = 16%, CT = 48%, and TT = 36%. Frequencies for CYP11B2 rs1799998 were: TT = 33%, TC = 50%, and CC = 17%. After 6 months of spironolactone treatment, change in the left ventricular ejection fraction (LVEF) differed by AGT rs699 (CC, 14.6%; TC, 7.9%; TT, 2.7%; P = 2.1E‐26), and CYP11B2 rs1799998 (TT, 9.1%; TC, 8.7%; CC, 1.4%; P = 0.0006) genotypes. Multivariate linear regression showed that the AGT rs699 and CYP11B2 rs1799998 polymorphisms plus baseline serum potassium explained 71% of variability in LVEF improvement (P = 0.001), 63% of variability in serum potassium increase (P = 2.25E‐08), and 39% of the variability in improvement in quality of life (P = 2.3E‐04) with spironolactone therapy. These data suggest that AGT and CYP11B2 genotypes as well as baseline serum K are predictors of spironolactone response in HFrEF.

Effects of the rs2244613 polymorphism of the CES1 gene on the antiplatelet effect of the receptor P2Y12 blocker clopidogrel

Background The aim of this study was to evaluate the association of the carriage of the rs2244613 polymorphism of the CES1 gene with clopidogrel resistance as well as to evaluate the effectiveness of antiplatelet therapy in the carriers of this marker who have had acute coronary syndrome (ACS). This study also analyzes the procedure of percutaneous coronary intervention and compares the rs2244613 carrier rate between patients with ACS and healthy participants. Methods The study involved 81 patients diagnosed with ACS and 136 conditionally healthy participants. The optical detection of platelet agglutination by VerifyNow was employed to measure residual platelet reactivity in patients with ACS. The rs2244613 polymorphism was determined using real-time polymerase chain reaction. Results According to the results, the AA genotype of the rs2244613 polymorphism of the CES1 gene was detected in 37 patients (45.6%), the CA genotype in 42 patients (51.8%) and the CC genotype in 2 patients (2.6%). The level of residual platelet reactivity in rs2244613 carriers was higher compared with patients who did not have this allelic variant: 183.23 PRU ± 37.24 vs. 154.3 PRU ± 60.36 (p = 0.01). The frequencies of the minor allele C were 28.4% and 28.3% in patients with ACS and healthy participants, respectively. The results of the linear statistical model PRU due to CES1 genotype were as follows: df = 1, F = 6.96, p = 0.01). The standardized beta was 0.285 (p = 0.01) and R2 was 0.081. However, we also added CYP2C19*2 and *17 into the linear regression model. The results of the model were as follows: df = 3, F = 5.1, p = 0.003) and R2 was 0.166. Conclusions We identified a statistically significant correlation between the carriage of the rs2244613 polymorphism of the CES1 gene and the level of residual platelet aggregation among patients with ACS and the procedure of percutaneous coronary intervention.

The influence of SLC22A1 rs622342 and ABCC8 rs757110 genetic variants on the efficacy of metformin and glimepiride combination therapy in Egyptian patients with type 2 diabetes

Background: The incidence of Type 2 Diabetes Mellitus (T2DM) in Egypt is considered one of the highest in the world. Metformin and Sulfonylureas are usually prescribed together due to their efficacy and their relatively low cost. Organic cation transport 1, encoded by SLC22A1 gene, is the main transporter of metformin into hepatocytes, which is considered metformin site of action. Sulfonylureas enhance insulin release from pancreatic B-cells through binding to sulfonylurea receptor 1, encoded by ABCC8 gene. Single nucleotide polymorphisms in the SLC22A1 and ABCC8 genes might affect the response of each drug.

Aims: To investigate the influence of SLC22A1 rs622342 (A>C) and ABCC8 rs757110 (A>C) genetic variants on the efficacy of metformin and glimepiride combination therapy in Egyptian T2DM patients.

Methods: Observational cross-sectional study in which patients receiving metformin and glimepiride combination therapy for at least 6 months were included for genotyping and classified into either responders or non-responders, based on their HbA1C level.

Results: A total of 127 patients were included and genotyped. They were divided into 93 responders (HbA1C<7%) and 34 non-responders (HbA1C≥7%). Minor allele frequencies for rs622342 and rs757110 were 0.189 and 0.271, respectively. Only SLC22A1 rs622342 variant was found to be associated with the response of combination therapy, in which AA alleles carriers were 2.7-times more responsive to metformin than C allele carriers (Recessive model, odds ratio = 2.718, p = 0.025, 95% CI = 1.112–6.385).

Conclusion: Genotyping of rs622342 can be useful in predicting the response to metformin in combination therapy in Egyptian T2DM patients.

The clinical effects of CYP2C19 *2 allele frequency on Palestinian patients receiving clopidogrel after percutaneous coronary intervention

BackgroundCYP2C19 loss-of-function polymorphic alleles (*2 and *3) have been documented to impair clopidogrel metabolism, and represent a risk factor for major adverse cardiac events. CYP2C19 polymorphism exhibits marked ethnic heterogeneity. Objective To determine the prevalence of CYP2C19 *2 and *3 alleles in a cohort of Palestinian patients managed with percutaneous coronary intervention and dual antiplatelet therapy, and to determine their role in causing major adverse cardiac events. Setting The blood samples were collected at the European Gaza Hospital, and the molecular techniques performed at the molecular genetics laboratory of the Islamic university of Gaza. Method The frequency of CYP2C19 *2 and *3 alleles was determined in 110 patients managed with percutaneous coronary intervention and clopidogrel. Genotyping was performed by PCR-RFLP. Personal and clinical data was obtained from patient record and 6-month follow-up for major adverse cardiac events. Main outcome measureCYP2C19 genotype, personal and clinical data and incidence of major adverse cardiac events. Results The frequency of CYP2C19 *1, *2 and *3 alleles was 82.3%, 15.5% and 2.3% respectively. Genotyping analysis showed that, 67.3% were homozygotes for CYP2C19 *1, 27.3% were *1/*2, 2.7% with *1/*3 genotype, 1.8% were *2/*3 and 0.9% were *2/*2. These frequencies were consistent with those of Caucasian populations. According to this study the poor metabolizers phenotype frequency was 2.7%, which is in the same range reported in Caucasians (2-5%) and lower than Oriental populations 13-23%. A strong significant relation was found between major adverse cardiac events and carrying the variant allele CYP2C19 *2 (P = 0.001). On the other hand, there was no significant relation between major adverse cardiac events and carrying the variant allele CYP2C19 *3 (P = 0.324). Conclusion The CYP2C19 *2 allele is relatively common in our population, and its associated reduced metabolic activity deserves attention as it leads to an increased incidence of major adverse cardiac events in the follow-up of patients receiving clopidogrel.

Genetic Determinants of P2Y12 Inhibitors and Clinical Implications

There is significant interpatient variability in clopidogrel effectiveness, which is due in part to cytochrome P450 (CYP) 2C19 genotype. Approximately 30% of individuals carry CYP2C19 loss-of-function alleles, which have been consistently shown to reduce clopidogrel effectiveness after an acute coronary syndrome and percutaneous coronary intervention. Guidelines recommend consideration of prasugrel or ticagrelor in these patients. A clinical trial examining outcomes with CYP2C19 genotype-guided antiplatelet therapy is ongoing. In the meantime, based on the evidence available to date, several institutions have started clinically implementing CYP2C19 genotyping to assist with antiplatelet selection after percutaneous coronary intervention.

Pharmacogenetic and clinical predictors of response to clopidogrel plus aspirin after acute coronary syndrome in Egyptians

OBJECTIVES

Dual antiplatelet therapy (DAPT) with aspirin and clopidogrel reduces the risk for recurrent cardiovascular events after acute coronary syndrome (ACS). However, there is significant variation in response to DAPT that may be influenced by both genetic and nongenetic factors. This study aimed to assess the effect of genetic polymorphisms in PON-1, PEAR-1, P2Y12, CES1, and CYP2C19, along with clinical, demographic, and social factors, on variation in response to DAPT in Egyptians.

PARTICIPANTS AND METHODS

This study included 230 Egyptians treated with clopidogrel 75 mg/day and aspirin 81 mg/day for at least 12 months following their first ACS. Simple and multivariable logistic regression analyses were carried out to identify factors associated with major adverse cardiovascular events (MACE), defined as the occurrence of recurrent ACS, ischemic stroke, stent-related revascularization, or death, in clopidogrel-treated participants.

RESULTS

Using multivariable logistic regression analysis, the CYP2C19*2 polymorphism was the only genetic predictor of MACE [odds ratio (OR): 2.23, 95% confidence interval (CI): 1.15-4.33, P=0.01]. In addition, proton pump inhibitor use (OR: 4.77, 95% CI: 1.47-15.54, P=0.009) and diabetes (OR: 1.83, 95% CI: 1.03-3.26, P=0.03) were associated with higher cardiovascular risk, whereas statin use was associated with lower risk (OR: 0.43, 95% CI: 0.25-0.76, P=0.003). The contribution of these four genetic and nongenetic factors explained 19% of the variability in risk for MACE in Egyptians treated with DAPT.

CONCLUSION

These results highlight that CYP2C19*2, along with diabetes, and use of proton pump inhibitor and statin are important factors jointly associated with variability in clinical response to DAPT following ACS in Egyptians.

Clopidogrel utilization in patients with coronary artery disease and diabetes mellitus: should we determine CYP2C19*2 genotype?

PURPOSE

Clopidogrel non-responsiveness is multifactorial; several genetic and non-genetic factors may contribute to impaired platelet inhibition. The goal of this study is to determine the effect of the cytochrome P450 CYP2C19*2 polymorphism on the platelet response to clopidogrel in patients with and without diabetes mellitus (DM).

METHODS

We conducted an observational study in patients with coronary artery disease and consequent exposure to clopidogrel therapy (75 mg/day for at least 7 consecutive days). We have analyzed two groups of patients: group I (DM patients) and group II (non-diabetes mellitus patients). Platelet reactivity was assessed by the VerifyNow P2Y12 assay and high on clopidogrel platelet reactivity (HPR) was defined as P2Y12 reaction units (PRU) ≥ 208. Genotyping for CYP2C19*2 polymorphism was performed by PCR-RFLP.

RESULTS

We have included 150 subjects (76 DM and 74 non-diabetes mellitus patients). The carriage of CYP2C19*2 allele, in DM patients, was significantly associated to HPR (odds ratio (OR) 4.437, 95% confidence interval (CI) 1.134 to 17.359; p = 0.032). Furthermore, 8.4% of the variability in percent inhibition by clopidogrel could be attributed to CYP2C19*2 carrier status. However, in non-diabetes mellitus patients, there was no significant difference in platelet response to clopidogrel according to the presence or absence of CYP2C19*2 allele carriage (OR 1.260, 95% CI 0.288 to 5.522; p = 0.759).

CONCLUSIONS

Our study suggests that the carriage of CYP2C19*2 polymorphism, in DM patients, might be a potential predictor of persisting HPR in these high-risk individuals.

TRIAL REGISTRATION

Clinical Trials.gov NCT03373552 (Registered 13 December 2017).

CYP2C19 Genotype is an Independent Predictor of Adverse Cardiovascular Outcome in Iraqi Patients on Clopidogrel After Percutaneous Coronary Intervention

To determine the impact of CYP2C19 genotyping on the occurrence of major adverse cardiovascular events (MACE), in cohort of Iraqi patients on clopidogrel after percutaneous coronary intervention (PCI), a total of 201 Iraqi patients undergoing the latter procedure were enrolled. All enrollees had their CYP2C19 genotyped using polymerase chain reaction and reverse hybridization. Genotyping revealed that CYP2C19 *1, *17, *2, and *8 allele frequencies were, respectively, 0.604, 0.276, 0.117, and 0.0026. After the exclusion of those with 2 loss of function alleles, 186 patients were available for follow-up as long as they were on clopidogrel, or until MACE occurred, which was encountered in 8.6% after a median of 12 months. Among predictors associated with MACE was the carriage of one CYP2C19 loss of function allele {hazard ratio (HR) 8.6 [confidence interval (CI) 3.15-23.4]; P < 0.0005}, hypertension [HR 3.74 (CI 1.06-13.16); P = 0.04], reduced ventricular function [HR 3.88 (1.43-10.54); P = 0.008], and history of previous myocardial infarction [HR 4.9 (CI 1.48-11.33); P = 0.007] by univariate analysis, although only CYP2C19 genotype remained significant by multivariate analysis [HR 11.88 (CI 3.25-43.44); P < 0.0005]. The latter observation favors CYP2C19 genotype-guided antiplatelet therapy and extending the use of alternative antiplatelet drugs to those with single loss of function allele after percutaneous coronary intervention.

Effect of cytochrome P450 2C19*17 allelic variant on cardiovascular and cerebrovascular outcomes in clopidogrel-treated patients: A systematic review and meta-analysis

Background:

We aimed to evaluate the associations of gain-of-function allele of CYP2C19*17 and risk of clinical events in clopidogrel-treated patients with cardiovascular and cerebrovascular diseases (CCVDs).

Materials and Methods:

Literature search was conducted in PubMed, EMBASE, and Cochrane Library. Odds ratio (OR) combined with 95% confidence interval (CI) was the pooled statistics. Subgroup analysis was performed by disease type, bleeding events, and race.

Results:

Thirteen eligible studies involving 14,239 patients with CYP2C19*17 carriers or noncarriers were included in the meta-analysis. CYP2C19*17 was significantly related to decreased risk of major adverse cardiovascular and cerebrovascular events (MACCEs) in patients with coronary artery disease (CAD) (OR = 0.76, 95% CI: 0.60–0.98, P = 0.03), however, irrelevant with stent thrombosis in neither CAD nor ischemic heart disease patients. CYP2C19*17 was also significantly linked to decreased risk of high platelet reactivity (HPR) in CCVD patients (OR = 0.61, 95% CI: 0.43–0.88, P = 0.008). Meanwhile, CYP2C19*17 was significantly associated with bleeding risk in CCVD patients (OR = 1.89, 95% CI: 1.09–3.25, P = 0.02) but not related to major bleeding risk (OR = 1.35, 95% CI: 0.87–2.08, P = 0.18). Several outcomes in Caucasian subgroup were reverse to the overall results, such as bleeding events and HPR, which lacked significance.

Conclusion:

CYP2C19*17 had a significant effect on the reduced risks of MACCE and HPR as well as increased bleeding risk, but not on the risks of stent thrombosis and major bleeding in clopidogrel-treated CCVD patients. Outcomes might be different in different races.

Impact of Genetic Polymorphisms on Phenytoin Pharmacokinetics and Clinical Outcomes in the Middle East and North Africa Region

BACKGROUND

Genetic polymorphisms are known to influence outcomes with phenytoin yet effects in the Middle East and North Africa region are poorly understood.

OBJECTIVES

The objective of this systematic review was to evaluate the impact of genetic polymorphisms on phenytoin pharmacokinetics and clinical outcomes in populations originating from the Middle East and North Africa region, and to characterize genotypic and allelic frequencies within the region for genetic polymorphisms assessed.

METHODS

MEDLINE (1946-3 May, 2017), EMBASE (1974-3 May, 2017), Pharmacogenomics Knowledge Base, and Public Health Genomics Knowledge Base online databases were searched. Studies were included if genotyping and analyses of phenytoin pharmacokinetics were performed in patients of the Middle East and North Africa region. Study quality was assessed using a National Institutes of Health assessment tool. A secondary search identified studies reporting genotypic and allelic frequencies of assessed genetic polymorphisms within the Middle East and North Africa region.

RESULTS

Five studies met the inclusion criteria. CYP2C9, CYP2C19, and multidrug resistance protein 1 C3435T variants were evaluated. While CYP2C9*2 and *3 variants significantly reduced phenytoin metabolism, the impacts of CYP2C19*2 and *3 variants were unclear. The multidrug resistance protein 1 CC genotype was associated with drug-resistant epilepsy, but reported impacts on phenytoin pharmacokinetics were conflicting. Appreciable variability in minor allele frequencies existed both between and within countries of the Middle East and North Africa region.

CONCLUSIONS

CYP2C9 decrease-of-function alleles altered phenytoin pharmacokinetics in patients originating from the Middle East and North Africa region. The impacts of CYP2C19 and multidrug resistance protein 1 C3435T variants on phenytoin pharmacokinetic and clinical outcomes are unclear and require further investigation. Future research should focus on the clinical outcomes associated with phenytoin therapy. PROSPERO 2017: CRD42017057850.

Pharmacokinetic and Pharmacodynamic Responses to Clopidogrel: Evidences and Perspectives

Clopidogrel has significantly reduced the incidence of recurrent atherothrombotic events in patients with acute coronary syndrome (ACS) and in those undergoing percutaneous coronary intervention (PCI). However, recurrence events still remain, which may be partly due to inadequate platelet inhibition by standard clopidogrel therapy. Genetic polymorphisms involved in clopidogrel’s absorption, metabolism, and the P2Y12 receptor may interfere with its antiplatelet activity. Recent evidence indicated that epigenetic modification may also affect clopidogrel response. In addition, non-genetic factors such as demographics, disease complications, and drug-drug interactions can impair the antiplatelet effect of clopidogrel. The identification of factors contributing to the variation in clopidogrel response is needed to improve platelet inhibition and to reduce risk for cardiovascular events. This review encompasses the most recent updates on factors influencing pharmacokinetic and pharmacodynamic responses to clopidogrel.

Impact of CYP2C19 Variants on Clinical Efficacy of Clopidogrel and 1-Year Clinical Outcomes in Coronary Heart Patients Undergoing Percutaneous Coronary Intervention

The impact of pharmacogenetic variants of cytochrome P450 2C19 (CYP2C19) on clopidogrel-mediated effects on platelet inhibition, inflammatory response and endothelial function, as well as risk of major adverse cardiovascular events (MACE), in coronary heart patients undergoing percutaneous coronary intervention (PCI) was investigated. To this end, we assessed the residual platelet aggregation rate (RPA), maximal aggregation rate (MAR) and plasma levels of sCD40L, sP-selectin, MMP-9, sVCAM-1 and sE-selectin after 24 h of PCI in 559 patients treated with clopidogrel and followed up for 1 year for evidence of MACE. CYP2C19^*2 and ^*3 variants were identified using a clopidogrel-sensitive gene detection kit. Our results showed higher RPA and MAR as well as increased sE-selectin, sCD40L, sP-selectin, MMP-9, and sVCAM-1 levels in CYP2C19 intermediate metabolizer (IM, CYP2C19^*1/^*2, or ^*1/^*3), poor metabolizer (PM, CYP2C19^*2/^*2, ^*2/^*3, or ^*3/^*3) and combined IM+PM groups, relative to those in extensive metabolizers (EM, CYP2C19^*1/^*1). In total, 519 patients completed 1 year of follow-up, among which 69 (13.3%) experienced MACE. The risk of MACE in CYP2C19 IM+PM patients was 2.664 times higher than that in CYP2C19 EM patients (OR = 2.664 (1.397–5.193), P = 0.004). The data suggest that CYP2C19^*2 and ^*3 variants modulate the drug efficacy of clopidogrel in coronary heart patients undergoing PCI and further enhance the risk of MACE. Accordingly, CYP2C19 pharmacogenetic profiling may be beneficial for coronary heart patients undergoing PCI to predict the efficacy of treatment with clopidogrel. We propose that IM and PM patients should benefit from treatment with higher clopidogrel doses to improve efficacy and reduce the incidence of MACE.