The risk of clopidogrel resistance is associated with ABCB1 polymorphisms but not promoter methylation in a Chinese Han population

A review on regulation of DNA methylation during post-myocardial infarction

Myocardial infarction (MI) imposes a huge medical and economic burden on society, and cardiac repair after MI involves a complex series of processes. Understanding the key mechanisms (such as apoptosis, autophagy, inflammation, and fibrosis) will facilitate further drug development and patient treatment. Presently, a substantial body of evidence suggests that the regulation of epigenetic processes contributes to cardiac repair following MI, with DNA methylation being among the notable epigenetic factors involved. This article will review the research on the mechanism of DNA methylation regulation after MI to provide some insights for future research and development of related drugs.

DNA methylation profile in the whole blood of acute coronary syndrome patients with aspirin resistance

BACKGROUND

Aspirin resistance (AR) results in major adverse cardiovascular events, and DNA methylation might participate in the regulation of this pathological process.

METHODS

In present study, a sum of 35 patients with AR and 35 non-AR (NAR) controls were enrolled. Samples from 5 AR and 5 NAR were evaluated in an 850 BeadChip DNA methylation assay, and another 30 AR versus 30 NAR were evaluated to validate the differentially methylated CpG loci (DML). Then, qRT-PCR was used to investigate the target mRNA expression of genes at CpG loci. Finally, Gene Ontology (GO) as well as Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to reveal the enriched pathways.

RESULTS

The AR and NAR groups displayed significant differences in DNA methylation at 7707 positions, with 270 hypermethylated sites (e.g., cg09555818 located in APOC2) and 7437 sites hypomethylated sites (e.g., cg26828689 located in SLC12A5). Six DML were validated by pyrosequencing, and it was confirmed that DNA methylation (cg16391727, cg21008208, cg21293749, and cg13945576) was related to the increasing risk of AR. The relative mRNA expression of the ROR1 gene was also associated with AR (p = 0.007), suggesting that the change of cg21293749 in DNA methylation might lead to differential ROR1 mRNA expression, ultimately resulting in AR. Furthermore, the identified differentially methylated sites were associated with the molecular pathways such as circadian rhythms and insulin secretion.

CONCLUSION

Hence, the distinct DNA methylation might play a vital role in the biological regulation of AR through the pathways such as circadian rhythms.

Gene polymorphisms of insulin secretion signaling pathway associated with clopidogrel resistance in Han Chinese population

BACKGROUND

Due to the loss of responsiveness to insulin, diabetes mellitus (DM) patients develop increased platelet reactivity and reduced response to antiplatelet agents. Nevertheless, the relationship between the single-nucleotide polymorphisms (SNP) of the signal pathway gene of insulin secretion and the effect of clopidogrel is elusive.

METHODS

Blood samples were collected from patients administered with dual-antiplatelet therapy (clopidogrel, 75 mg, once daily and aspirin, 100 mg, once daily) after 5 days and completed test within 4 h. The VerifyNow P2Y12 assay was used to measure the platelet functions, and the results were expressed as a P2Y12 reaction unit (PRU). Notably, the selected SNPs were analyzed to demonstrate the functionality of genetic variants.

RESULTS

Analysis of the study population showed that old age, lower plasma albumin (ALB) level, higher creatinine (CREA) level, higher uric acid (UA) level, lower platelet (PLT) count, and lower plateletcrit (PCT) potentially increased the risk of clopidogrel resistance. In a single-nucleotide polymorphism rs6056209 of the PCLB1 gene, the AG genotype was a risk factor for clopidogrel resistance (p < 0.05, OR = 1.574). Similarly, the CC and AG genotype in GNAS rs7121 and CCKAR rs1800857 were protective factors (p < 0.05, OR = 0.094; p <0.05, OR = 0.491). TT was a protective factor in rs10814274 of the CREB3 gene (p < 0.05, OR = 0.444). In the RAPGEF4 gene polymorphism rs17746510, TG was the protective genotype, and the TT genotype was a risk factor for clopidogrel resistance. GCG rs5645 was confirmed; there was a relationship between genotypes containing A or G and clopidogrel resistance.

CONCLUSION

Single-nucleotide polymorphisms of insulin secretion signaling pathway genes trigger clopidogrel resistance.

Increase in the risk of clopidogrel resistance and consequent TIMI flow impairment by DNA hypomethylation of CYP2C19 gene in STEMI patients undergoing primary percutaneous coronary intervention (PPCI)

Clopidogrel resistance is an important risk factor of ischemic event recurrence after optimal antiplatelet therapy. This study aims to investigate the role of CYP2C19 gene DNA methylation as one of the epigenetic factors for the risk of clopidogrel resistance in STEMI patients undergoing PPCI. ST-segment elevation myocardial infarction (STEMI) patients undergoing PPCI were pretreated with clopidogrel, and their platelet function was measured using VerifyNow™ assay. The criteria for high on-treatment platelet reactivity (HPR) were defined according to the expert consensus criteria (PRU >208). DNA methylation of the CYP2C19 gene was performed using bisulfite genomic sequencing technology. Furthermore, clinical, laboratory, and angiographic data including TIMI flow were collected. Among 122 patients, clopidogrel resistance was found in 22%. DNA methylation level percentage was lower in the clopidogrel resistance group (76.7 vs. 88.8, p-value .038). But, the <50% methylation group was associated with increased risk of clopidogrel resistance (OR =4.5, 95%CI =2.1-9.3, p-value = .018). This group was also found to have suboptimal post-PCI TIMI flow (OR =3.4 95%CI =1.3-8.7, p-value =.045). The lower DNA methylation level of the CYP2C19 gene increases the risk of clopidogrel resistance and subsequent poorer clinical outcome.

The expression profile of platelet-derived miRNA in coronary artery disease patients with clopidogrel resistance

Clopidogrel is widely used for antiplatelet therapy in patients with coronary artery disease (CAD), but clopidogrel resistance (CR) is relatively common in these patients. The goal of our study was to explore the platelet-derived miRNA expression profile of CR in CAD patients. In this study, 66 CAD patients treated with dual antiplatelet therapy (clopidogrel 75 mg once daily plus aspirin 100 mg once daily) were included. According to inhibition of platelet aggregation (IPA), we divided these patients into CR group (IPA <30%) and control group (IPA ≥30%). The concentrations of clopidogrel and clopidogrel active metabolites in plasma were obtained using UHPLC-Q-Orbitrap HRMS method. The platelet-derived miRNA expression profiles of these subjects were detected by high-throughput sequencing and qRT-PCR. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used for function prediction of differentially expressed miRNAs. Our results suggested no significant difference of clopidogrel and active metabolic derivative concentrations between CR group and control group. Correlation analysis showed no significant association between clopidogrel concentration and IPA; active metabolic derivative and IPA. In addition, 67 platelet-derived miRNAs were differentially expressed between three CR and three control patients. After adjusting, eight miRNAs might be related to CR in CAD. In our validation cohort (30 CR patients and 30 control group), miRNA-142-3p and miRNA-24-3p expression levels were significantly upregulated, and miRNA-411-3p expression was significantly downregulated in the CR group. In conclusion, the miRNA-142-3p, miRNA-24-3p, and miRNA-411-3p might be potential markers for CR in CAD patients.

ABCB1 polymorphism in clopidogrel-treated Montenegrin patients

Clopidogrel is an antiplatelet drug that displays significant interindividual variability in treatment response. Its bioavailability depends on the function of P-glycoprotein (P-gp), which is coded by a highly polymorphic ABCB1 gene. Thus, the aim of this study was to investigate the effect of ABCB1 genetic polymorphism on clopidogrel efficacy and safety and to determine the frequency distribution of its most common single nucleotide polymorphisms (SNPs) in 106 Montenegrin cardiology patients. Clopidogrel efficacy and safety were followed up during 1 year after hospitalization, with the lack of efficacy and adverse drug reactions observed in 11 (10.4%) and 8 patients (7.5%), respectively. Genotyping for ABCB1 SNPs rs1128503 (1236C > T), rs2032582 (2677G > A/T), and rs1045642 (3435C > T) was performed by the real-time PCR method, and the variant alleles were detected with the frequencies of 42.9, 44.8, and 52.8%, respectively. No significant association was observed between any of the examined genotypes and clopidogrel efficacy (p = 0.253) or safety (p = 0.424). Due to small sample size, co-treatment with other drugs, and other genetic factors not taken into account, we believe the absence of correlation between ABCB1 genotypes and indicators of clopidogrel efficacy and safety in this study should be apprehended conditionally, and that larger and better-controlled studies are warranted.

Associations of PER3 polymorphisms with clopidogrel resistance among Chinese Han people treated with clopidogrel

Background

Changes in circadian rhythm are related to various diseases, such as immune system diseases and cardiovascular diseases. The PERIOD3 (PER3) clock gene is one of the most important genes in the rhythm regulation system. Our goal was to evaluate the possible association between the PER3 rs228729 (T/C) polymorphism or PER3 rs2797685(T/C) polymorphism and clopidogrel resistance (CR) and to study the impact of clinical baseline data on clopidogrel resistance.

Methods

PER3 polymorphisms rs2797685 (T/C) and rs228729 (T/C) were assessed in 156 patients with (72) and without (84) CR. Blood samples were collected and analyzed after the application of clopidogrel for interventional therapy.

Results

Age, albumin, PLT, and PCT levels influenced the risk of CR (p < 0.05). For rs2797685, when the PCT value was greater than 0.19, patients with the TT + TC genotype had an increased risk of clopidogrel resistance compared with those with the CC genotype (PCT ≥ 0.19, p = 0.014; PCT p = 0.004). In patients with albumin values greater than 40 or PCT greater than 0.19, those with the rs228729 TT + TC genotype had an increased risk of clopidogrel resistance compared with those with the CC genotype (albumin≥40, TT+TC:CC, p = 0.01, albumin p = 0.005; PCT ≥ 0.19, TT+TC:CC, p < 0.001, PCT p = 0.004). Logistic regression analysis of clinical baseline data and genotype showed that high albumin is a protective factor against clopidogrel resistance. The PER3 gene polymorphism has no clear correlation with clopidogrel resistance.

Conclusion

In summary, our research shows that PER3 SNPs may be helpful to assess the pathogenesis of CR.

Clopidogrel Resistance Is Associated With DNA Methylation of Genes From Whole Blood of Humans

Antiplatelet therapy has become a cornerstone in the treatment of coronary heart disease (CHD). However, due to high-residual-platelet-reactivity, clopidogrel resistance (CR) is a common phenomenon, and it is rarely known about the relationship between CR and epigenetic changes. This study compared the whole genomic methylation patterns of blood samples from patients with CR (n = 6) and non-CR (n = 6) with the Human Methylation 850K BeadChip assay. We explored differentially methylated CpG sites, genes, and pathways using bioinformatics profiling. The CR and control groups showed significantly different DNA methylation at 7,098 sites, with 979 sites showing hypermethylation and 6,119 sites showing hypomethylation. The pyrosequencing method was used to validate four differentially methylated CpG loci (cg23371584, cg15971518, cg04481923, cg22507406), confirming that DNA methylation was associated with the risk of CR (30 CR vs. 30 non-CR). The relative mRNA expression of the four genes (BTG2, PRG2, VTRNA2-1, PER3) corresponding to the loci above was also associated with CR, suggesting that alterations in DNA methylation may affect the expression of these four genes, eventually resulting in CR. Additionally, differentially methylated sites are partially related to genes and pathways that play key roles in process of circadian entrainment, insulin secretion, and so on. Hence, the mechanism and biological regulation of CR might be reflected through these epigenetic alterations, but future research will need to address the causal relationships.

A SNP involved in alternative splicing of ABCB1 is associated with clopidogrel resistance in coronary heart disease in Chinese population

Although many scientists are studying the association between genetic polymorphism of ABCB1 and CR in patients, the molecular mechanism has not been further studied in patients with CHD. This study investigated the relationship between SNP of the ABCB1 gene in patients with CHD and CR, and whether the polymorphism of the ABCB1 gene affects the AS of the gene. 741 patients were enrolled in the study, 316 CR cases and 425 NCR cases. The correlation between CR risk and clinical-pathological characteristics were studied. Additionally, the five SNPs were analysed by PCR and Mass Array genotyping methods. Furthermore, silicon analysis was used to predict whether the polymorphism affects the process of AS. Results showed that there was a significant correlation between rs1045642 polymorphism and CR in genotyping and allele analysis. The rs1045642 polymorphism of the ABCB1 gene of CHD patients carrying the A allele are more likely to develop CR. Silicon analysis showed that rs1045642 generated a new ESE sequence which might affect AS of ABCB1 gene. We hypothesize that the mechanism of CR might be caused by a change in the AS caused by the polymorphism of the gene. Thus, this work provides guidance for the clinical use of clopidogrel.

Effects of the ABCB1 C3435T single nucleotide polymorphism on major adverse cardiovascular events in acute coronary syndrome or coronary artery disease patients undergoing percutaneous coronary intervention and treated with clopidogrel: A systematic review and meta-analysis

INTRODUCTION

The effects of the ABCB1 C3435T genetic polymorphism on clopidogrel responses are conflicting and inconclusive especially in patients undergoing percutaneous coronary intervention (PCI). This study examined the pooled risk of major adverse cardiovascular events (MACE) and bleeding events associated with the ABCB1 C3435T polymorphism in acute coronary syndrome or coronary artery disease patients undergoing PCI and treated with clopidogrel.

AREAS COVERED

Literature was searched in different resources for eligible studies. The pooled risk ratio was measured using RevMan software, with p<0.05 (two-sided) set as statistically significant.

EXPERT OPINION

The ABCB1 C3435T homozygous mutant (TT) was associated with significantly increased risk of MACE compared to either wild type genotype (CC) or the combination of wild type and heterozygous genotypes (TT vs. CC: RR 1.33; 95% CI 1.06-1.68; p=0.02; TT vs. CC+CT: RR 1.32; 95% CI 1.10-1.60; p=0.004). Safety outcomes, i.e. bleeding events were not significantly different between the genetic models investigated (TT vs. CC: RR 1.93; 95% CI 0.86-4.35; p=0.11; TT vs. CC+CT: RR 1.36; 95% CI 0.89-2.09; p=0.16; CT+TT vs. CC: RR 1.20; 95% CI 0.59-2.44; p=0.61). It is suggested that ABCB1 C3435T genotype should be tested for ACS/CAD patients undergoing PCI to ensure optimum therapy of clopidogrel.

Association of PON1 gene promoter DNA methylation with the risk of Clopidogrel resistance in patients with coronary artery disease

BACKGROUND AND AIMS

The failure of therapeutic response to clopidogrel in platelet inhibition, which is called clopidogrel resistance (CR), is more likely to cause cardiovascular events. We aimed to study the contribution of promoter DNA methylation of paraoxonase 1 (PON1) to the risk of clopidogrel poor response.

METHODS

Through VerifyNow P2Y12 assay, patient' platelet functions were measured. Among 57 non-CR and 49 CR patients, the levels of DNA methylation in four CpG dinucleotides on the PON1 promoter were tested using bisulfite pyrosequencing technology. Besides, the relative expression of PON1 mRNA was analyzed by quantitative real-time PCR. Logistic regression was applied to investigate the interaction of PON1 methylation and clinical factors in CR.

RESULTS

In the subgroup with dyslipidemia, we discovered that higher CpG4 levels of the PON1 promoter indicated a poorer clopidogrel response (cases versus controls (%): 51.500 ± 14.742 vs 43.308 ± 10.891, P = 0.036), and the PON1 mRNA expression was reduced in CR patients. Additionally, the logistic regression indicated that higher level of albumin and the index of ALT were related to a lower risk of CR, and the index of AST as well as the quantity of stent may be positively associated with CR.

CONCLUSIONS

The DNA methylation of CpG4 in the PON1 promoter would lead to a low expression of PON1 mRNA, which might induce clopidogrel resistance in the patients with dyslipidemia, and the number of stents might be a risk for CR.

Impact of genetic polymorphisms on platelet function and response to anti platelet drugs

Cardiovascular genomic consists in the identification of polymorphic genes responsible for the susceptibility to cardiovascular disease including coronary artery disease (CAD). Genes involved in platelet activation and aggregation play a key role in the predisposition to CAD. A considerable inter-variability of platelet response to agonists and to drugs exists and in particular the hyper-reactivity phenotype seems to be heritable. Besides glycoproteins and receptors expressed on platelets surface whose mutations significantly impact on platelet function, moreover researchers in the last decades have paid great attention to the genes involved in the response to anti-platelet drugs, considering their pivotal role in the treatment and outcomes of CAD patients especially those undergoing PCI. With the outbreak of advanced techniques developed to analyse human genetic footprints, researchers nowadays have shifted from genetic linkage analysis and a candidate gene approach toward genome-wide association (GWAS) studies and the analysis of miRNA-mRNA expression profiles.

Identification of Diatraea spp. (Lepidoptera: Crambidae) based on cytochrome oxidase II

Diatraea spp. (Lepidoptera: Crambidae) are a group of insects that are agriculture pests in many economically relevant crops such as sugarcane, sorghum, corn and rice. Recognized species for this genus respond differentially to natural enemies used in their biological control, emphasizing the importance of species in a regional approach. Currently, identification is based on the male genitalia. However, the availability of specimens collected from field and subjectivity based on the character recognition can seriously hamper species identification, and therefore result in inadequate pest management. To overcome this, individuals of Diatraea spp. preliminarily classified male genitalia and obtained from reared conditions and the field (both derived from natural populations occurring in Colombia) were analyzed using genitalic morphometry and molecular biology specifically using a fragment of the cytochrome oxidase subunit II (CO II) mitochondrial gene. Although morphometric analysis did not show any overriding results regarding genitalia morphology, the bioinformatics analyses of CO II sequences resulted in an adequate classification of the individuals within the recognized species. It also, revealed that the occurrence of clades associated with geographical distribution may be associated with cryptic species. The latter was also confirmed by a Single-Strand Conformation Polymorphism (SSCP) methodology evaluating the same fragment of CO II. This experimental approach allows properly recognizing each species and in consequence is proposed as an effective tool in Diatraea species identification.