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)

Exploring cytochrome P450 under hypoxia: potential pharmacological significance in drug metabolism and protection against high-altitude diseases

High-altitude hypoxia affects the human respiratory, central nervous, cardiovascular, and endocrine systems. These outcomes affect the expression of cytochrome P450 (CYP), the most important family of metabolic enzymes in the body that is involved in the metabolism of both exogenous and endogenous substances (such as arachidonic acid, vitamins, and steroids). Hypoxia influences CYP expression and activity, mediating changes in drug and endogenous substance metabolism, with endogenous metabolites playing a significant role in controlling high-altitude diseases. However, the mechanisms regulating CYP changes under hypoxic conditions and the effects of CYP changes on drug and endogenous metabolism remain unclear. We explored how changes in CYP expression and activity during hypoxia affect the metabolism of drugs and endogenous substances, such as arachidonic acid, vitamins, and steroid hormones, and how CYPs are controlled by nuclear receptors, epigenetic modifications, cytokines, and gut microbiota during hypoxia. Special attention will also be given to the complex role of CYP and its metabolites in the pathophysiology of high-altitude diseases to provide valuable insights for plateau medicine research. SIGNIFICANCE STATEMENT: Cytochrome P450 is a class of monooxygenases that metabolize xenobiotics and endogenous substances. Hypoxia affects the expression and activity of cytochrome P450, and this in turn affects the metabolism of drugs and endogenous substances, leading to altered clinical efficacy and the development of hypoxia-associated diseases. A comprehensive understanding of the changes and regulatory mechanisms of cytochrome P450 under hypoxic conditions can improve therapeutic protocols in hypoxic environments and provide new ideas for the targeted treatment of hypoxic diseases.

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.

The role of clopidogrel resistance-related genetic and epigenetic factors in major adverse cardiovascular events among patients with acute coronary syndrome after percutaneous coronary intervention

Despite patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) and receiving clopidogrel therapy, some patients still experience major adverse cardiovascular events (MACEs). Clopidogrel resistance, which may be regulated by genetic and epigenetic factors, may play a role in MACEs. This study aimed to determine the association between genetic (CYP2C19 and P2Y12 polymorphisms) and epigenetic (DNA methylation of CYP2C19 and P2Y12 and miRNA-26a expression) factors and their effects on MACEs among post-PCI patients. Post-PCI patients who received a standard dosage of clopidogrel at Harapan Kita Hospital between September 2018 and June 2020 were included in this study. MACEs were observed in patients within 1 year after PCI. Platelet aggregation was assessed using light transmission aggregometry (LTA). DNA methylation of CYP2C19 and P2Y12 was assessed using the bisulfite conversion method. CYP2C19 and P2Y12 polymorphisms and miRNA-26a expression were evaluated using quantitative real-time polymerase chain reaction (qRT-PCR). Among a total of 201 subjects, 49.8% were clopidogrel-resistant, and 14.9% experienced MACEs within 1 year after PCI (death was 7.5%). Hypomethylation of CYP2C19 (p = 0.037) and miRNA-26a upregulation (p = 0.020) were associated with clopidogrel resistance. CYP2C19^*2/^*3 polymorphisms (p = 0.047) were associated with MACEs in 1 year. This study demonstrated that hypomethylation of CYP2C19 and miRNA-26a upregulation increased the risk of clopidogrel resistance in post-PCI patients, but there was no correlation between clopidogrel resistance and MACEs. However, CYP2C19^*2/^*3 polymorphisms were the factors that predicted MACEs within 1 year.

Impact of DNA methylation on ADME gene expression, drug disposition and efficacy

Interindividual differences in drug response have always existed in clinical treatment. Genes involved in drug absorption, distribution, metabolism, and excretion (ADME) play an important role in the process of pharmacokinetics. The effects of genetic polymorphism and nuclear receptors on the expression of drug metabolism enzymes and transporters can only explain some individual differences in clinical treatment. Several key ADME genes have been demonstrated to be regulated by epigenetic mechanisms that can potentially affect interindividual variability in medical treatment. Emerging studies have focused on the importance of DNA methylation for ADME gene expression and for drug response. Among them, the most studied is anti-tumor drugs, and followed by anti-tuberculous and anti-platelet drugs. Therefore, we provide an epigenetics perspective on variability in drug response. The review summarizes the correlation between ADME gene expression and DNA methylation, including the exact methylation locations, and focuses on the corresponding drug disposition and effects to illuminate interindividual differences in clinical medication.

Clinical and pharmacological parameters determine relapse during clopidogrel treatment of acute coronary syndrome

The therapeutic efficacy of clopidogrel as an anti-platelet drug varies among individuals, being the mainstream hypothesis that its bioavailability depends on the individual genetic background and/or interactions with other drugs. A total of 477 patients receiving double anti-aggregation therapy with aspirin and clopidogrel, after suffering a first event, were followed for 1 year to record relapse, as a surrogate end point to measure their therapeutic response, as defined by presenting with an acute coronary event (unstable angina, STEMI, or NSTEMI), stent thrombosis/restenosis or cardiac mortality. Anthropometric, clinical and pharmacological variables along with CYP2C19 genotypes were analyzed for their association with the disease relapse phenotype. Only 75 patients (15%) suffered a relapse, which occurred during the first six months of therapy, with a peak at 4.5 months. An initial univariate analysis identified that patients in the relapse group were significantly older (67.4 ± 11.0 vs 61.6 ± 12.3 years old) and presented with diffuse coronary disease, insulin-dependent type 2 diabetes mellitus dyslipidemia, and arterial hypertension. A poor clinical response to the platelet anti-aggregation regime also occurred more frequently among patients taking, along with aspirin and clopidogrel, acenocoumarol and Calcium Channel Blockers, while no association was found according to CYP2C19 genotypes. A retrospective multivariate analysis indicated that patients belonging to the non-responder phenotype to treatment with aspirin and clopidogrel were older, presented with diffuse coronary disease, a group largely overlapping with type 2 insulin-dependent diabetes mellitus, and were taking dihidropyrimidinic calcium channel blockers. This article is protected by copyright. All rights reserved.