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

Abstract

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.

Clinical and Pharmacological Parameters Determine Relapse During Clopidogrel Treatment of Acute Coronary Syndrome

“…50 Moreover, the diabetic state also affects profoundly the epigenetic landscape, possibly altering the expression of genes whose products alter clopidogrel pharmacokinetics and pharmacodynamics. 19,20,51 Diabetics are, therefore, a population of patients at high risk of recurrent thrombotic events even under clopidogrel therapy. 32,33,52,53 Type 2 diabetes, especially the insulin-dependent type, was strongly associated with disease relapse in our study.…”

“…Physiologically, patients with type 2 diabetes mellitus are characterized by a prothrombotic status favored by resistance to antithrombotic physiological signals, shear‐induced aggregation, nonenzymatic glycation of platelet glycoproteins, changes in the structure and conformation of platelets, increased oxidative stress, and increased platelet turnover 50 . Moreover, the diabetic state also affects profoundly the epigenetic landscape, possibly altering the expression of genes whose products alter clopidogrel pharmacokinetics and pharmacodynamics 19,20,51 …”

“…18 Additionally, beyond specific germinal genetic variants, recent efforts have been directed to identify epigenetic footprints that may alter the expression of genes whose products may be related or are likely to be involved in the response to clopidogrel. 19,20 When testing pharmacokinetic and pharmacodynamic parameters of clopidogrel in young, healthy subjects, the interindividual variability seem to be unpredictable based on a single parameter, so clinical resistance is likely dependent on multiple factors beyond specific genotypes, including pharmacological interactions with other drugs and associated comorbidities. 21 Early studies have associated the use of proton pump inhibitors and calcium channel blockers (CCBs) with a reduced antiplatelet response ex vivo and decreased clinical efficacy of clopidogrel, 22,23 but there is no conclusive evidence of clinical relevance to date.…”

“…A recent report predicts that a compound pharmacogenomic polygenic response score, encompassing allelic variation at multiple genes that are associated with increased on‐treatment platelet reactivity, is able to generate a risk profile as the number of variants increases 18 . Additionally, beyond specific germinal genetic variants, recent efforts have been directed to identify epigenetic footprints that may alter the expression of genes whose products may be related or are likely to be involved in the response to clopidogrel 19,20 …”

Physiologically Based Pharmacokinetic (PBPK) Modeling of Clopidogrel and Its Four Relevant Metabolites for CYP2B6, CYP2C8, CYP2C19, and CYP3A4 Drug–Drug–Gene Interaction Predictions

“…Not well defined, this term is generally associated with a considerable attenuation of the inhibitory effect on platelet aggregation, with the specific mechanisms not yet conclusively investigated [ 16 ]. Genetic polymorphisms have been proposed as a possible cause, particularly of the CYP2C19 gene, resulting in rapid (RM), normal (NM), intermediate (IM), or poor metabolizer (PM) phenotypes [ 16 , 17 , 18 ]. About 3% of Caucasians exhibit a CYP2C19 PM phenotype, whereas the frequency is much higher in Asians, e.g., about 14% among Chinese, making the drug–gene interactions (DGIs) clinically relevant [ 19 ].…”