Cytochrome P450 3A4*22, PPAR-α, and ARNT polymorphisms and clopidogrel response

Effect of Dan-Lou tablets on coronary heart disease revealed by microarray analysis integrated with molecular mechanism studies

Dan-Lou tablets (DLT) effectively treat coronary heart disease (CHD). However, its pharmacological mechanism in CHD treatment requires further investigation. This study aimed to elucidate the underlying pharmacological mechanisms of DLT in the treatment of CHD through clinical trials, microarray research, bioinformatics analysis, and molecular mechanism research. In this study, DLT improved coagulation function, endothelial injury, and levels of lipids, metalloproteases, adhesion molecules, inflammatory mediators, and homocysteine. The results of molecular biology research demonstrated that DLT can increase the gene and protein expressions of meningioma expressed antigen 5 (MGEA5) and mouse doubleminute 2 (MDM2) and inhibited the gene and protein expressions of signal transcription and transcription activator 5 B (STAT5B), tropomyosin-1 (TPM1), and aromatic hydrocarbon receptor nuclear transpose (ARNT). The results indicate that DLT reduced the extent of vascular endothelial damage in CHD rats by reducing the expressions of STAT5B, TPM1, and MDM2; inhibiting the inflammatory reaction; and increasing the expressions of ARNT and MGEA5.

Effects of CYP3A4*22 and CYP3A5 on clinical outcome in patients treated with ticagrelor for ST-segment elevation myocardial infarction: POPular Genetics sub-study

Aims: To determine the clinical efficacy, adverse events and side-effect dyspnea of CYP3A4*22 and CYP3A5 expressor status in ticagrelor treated patients. Methods and results: Ticagrelor treated patients from the POPular Genetics randomized controlled trial were genotyped for CYP3A4*22 and CYP3A5*3 alleles. Patients were divided based on their genotype. In total 1,281 patients with ST-segment elevation myocardial infarction (STEMI) were included. CYP3A4*22 carriers (n = 152) versus CYP3A4*22 non-carrier status (n = 1,129) were not found to have a significant correlation with the primary thrombotic endpoint: cardiovascular death, myocardial infarction, definite stent thrombosis and stroke [1.3% vs. 2.5%, adjusted hazard ratio 1.81 (0.43-7.62) p = 0.42], or the primary bleeding endpoint: PLATO major and minor bleeding [13.2% vs. 11.3%, adjusted hazard ratio 0.93 (0.58-1.50) p = 0.77]. Among the CYP3A4*1/*1 patients, CYP3A5 expressors (n = 196) versus non-expressors (n = 926) did not show a significant difference for the primary thrombotic [2.6% vs. 2.5%, adjusted hazard ratio 1.03 (0.39-2.71) p = 0.95], or the primary bleeding endpoint [12.8% vs. 10.9%, adjusted hazard ratio 1.13 (0.73-1.76) p = 0.58]. With respect to dyspnea, no significant difference was observed between CYP3A4*22 carriers versus CYP3A4*22 non-carriers [44.0% vs. 45.0%, odds ratio 1.04 (0.45-2.42) p = 0.93], or in the CYP3A4*1/*1 group, CYP3A5 expressors versus CYP3A5 non-expressors [35.3% vs. 47.8%, odds ratio 0.60 (0.27-1.30) p = 0.20]. Conclusion: In STEMI patients treated with ticagrelor, neither the CYP3A4*22 carriers, nor the CYP3A5 expressor status had a statistical significant effect on thrombotic and bleeding event rates nor on dyspnea. Clinical Trial Registration: ClinicalTrials.gov, identifier NCT01761786.

Effect of CYP3A4*22 and PPAR-α Genetic Variants on Platelet Reactivity in Patients Treated with Clopidogrel and Lipid-Lowering Drugs Undergoing Elective Percutaneous Coronary Intervention

This study aims to determine whether genetic variants that influence CYP3A4 expression are associated with platelet reactivity in clopidogrel-treated patients undergoing elective percutaneous coronary intervention (PCI), and to evaluate the influence of statin/fibrate co-medication on these associations. A study cohort was used containing 1124 consecutive elective PCI patients in whom CYP3A4*22 and PPAR-α (G209A and A208G) SNPs were genotyped and the VerifyNow P2Y₁₂ platelet reactivity test was performed. Minor allele frequencies were 0.4% for CYP3A4*22/*22, 6.8% for PPAR-α G209A AA, and 7.0% for PPAR-α A208G GG. CYP3A4*22 was not associated with platelet reactivity. The PPAR-α genetic variants were significantly associated with platelet reactivity (G209A AA: −24.6 PRU [−44.7, −4.6], p = 0.016; A208G GG: −24.6 PRU [−44.3, −4.8], p = 0.015). Validation of these PPAR-α results in two external cohorts, containing 716 and 882 patients, respectively, showed the same direction of effect, although not statistically significant. Subsequently, meta-analysis of all three cohorts showed statistical significance of both variants in statin/fibrate users (p = 0.04 for PPAR-a G209A and p = 0.03 for A208G), with no difference in statin/fibrate non-users. In conclusion, PPAR-α G209A and A208G were associated with lower platelet reactivity in patients undergoing elective PCI who were treated with clopidogrel and statin/fibrate co-medication. Further research is necessary to confirm these findings.

CDK4/6 Inhibitors in Breast Cancer Treatment: Potential Interactions with Drug, Gene, and Pathophysiological Conditions

Palbociclib, ribociclib, and abemaciclib belong to the third generation of cyclin-dependent kinases inhibitors (CDKis), an established therapeutic class for advanced and metastatic breast cancer. Interindividual variability in the therapeutic response of CDKis has been reported and some individuals may experience increased and unexpected toxicity. This narrative review aims at identifying the factors potentially concurring at this variability for driving the most appropriate and tailored use of CDKis in the clinic. Specifically, concomitant medications, pharmacogenetic profile, and pathophysiological conditions could influence absorption, distribution, metabolism, and elimination pharmacokinetics. A personalized therapeutic approach taking into consideration all factors potentially contributing to an altered pharmacokinetic/pharmacodynamic profile could better drive safe and effective clinical use.

Genotyping and phenotyping CYP3A4\CYP3A5: no association with antiplatelet effect of clopidogrel

The objective of this study was to determine the impact of polymorphism of CYP3A subfamily isoenzymes (allelic variants of CYP3A4*22 and CYP3A5*3) on the efficacy clopidogrel in patients with an acute coronary syndrome (ACS), who have undergone percutaneous coronary intervention (PCI). Platelet activity was determined on a VerifyNow P2Y12 test system in 81 patients with ACS aged 37-91 who had PCI. The activity of CYP3A4/5 was expressed as the ratio of the concentrations of cortisol and 6β-hydroxycortisol was performed by using high performance liquid chromatography. Genotyping was performed by using real-time polymerase real-time chain reaction. The frequencies for the CYP3A5 gene, rs 776746, were identified as follows: 77 (95.1%)-CC, 4 (4.9%)-CT; the allele frequencies by loci for the CYP3A4, rs rs35599367, were as follows: 78 (96.3%)-GG, 3 (3.7%)-AG. There was no statistically significant genotype-dependent difference between the presence of a minor T and G alleles and the presence of clopidogrel resistance (OR 3.53; 95% CI 0.46-26.94; p = 0.233 and p = 0.443, respectively). The average level of the metabolic relationship (6β-hydroxycortisol/cortisol) between the clopidogrel-resistant group and the normal platelet reactivity group was not statistically significantly different: 3.3 ± 2.8 versus 3.2 ± 3.2; p = 0.947. So, the activity of CYP3A4/5 was not related to platelet aggregation rates in this model. Genotyping and phenotyping CYP3A4\CYP3A5 does not predict the antiplatelet effect of clopidogrel. More extensive research is required to establish their clinical relevance.

The pharmacogenetic control of antiplatelet response: candidate genes and CYP2C19

INTRODUCTION

Aspirin, clopidogrel, prasugrel and ticagrelor are antiplatelet agents for the prevention of ischemic events in patients with acute coronary syndromes (ACS), percutaneous coronary intervention (PCI) and other indications. Variability in response is observed to different degrees with these agents, which can translate to increased risks for adverse cardiovascular events. As such, potential pharmacogenetic determinants of antiplatelet pharmacokinetics, pharmacodynamics and clinical outcomes have been actively studied.

AREAS COVERED

This article provides an overview of the available antiplatelet pharmacogenetics literature. Evidence supporting the significance of candidate genes and their potential influence on antiplatelet response and clinical outcomes are summarized and evaluated. Additional focus is directed at CYP2C19 and clopidogrel response, including the availability of clinical testing and genotype-directed antiplatelet therapy.

EXPERT OPINION

The reported aspirin response candidate genes have not been adequately replicated and few candidate genes have thus far been implicated in prasugrel or ticagrelor response. However, abundant data support the clinical validity of CYP2C19 and clopidogrel response variability among ACS/PCI patients. Although limited prospective trial data are available to support the utility of routine CYP2C19 testing, the increased risks for reduced clopidogrel efficacy among ACS/PCI patients that carry CYP2C19 loss-of-function alleles should be considered when genotype results are available.

Role of peroxisome proliferator-activated receptors gene polymorphisms in type 2 diabetes and metabolic syndrome

Metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM) are the serious public health problems worldwide. Moreover, it is estimated that MetS patients have about five-fold greater risk of the T2DM development compared with people without the syndrome. Peroxisome proliferator-activated receptors are a subgroup of the nuclear hormone receptor superfamily of ligand-activated transcription factors which play an important role in the pathogenesis of MetS and T2DM. All three members of the peroxisome proliferator-activated receptor (PPAR) nuclear receptor subfamily, PPARα, PPARβ/δ and PPARγ are critical in regulating insulin sensitivity, adipogenesis, lipid metabolism, and blood pressure. Recently, more and more studies indicated that the gene polymorphism of PPARs, such as Leu¹⁶²Val and Val²²⁷Ala of PPARα, +294T > C of PPARβ/δ, Pro¹²Ala and C1431T of PPARγ, are significantly associated with the onset and progressing of MetS and T2DM in different population worldwide. Furthermore, a large body of evidence demonstrated that the glucose metabolism and lipid metabolism were influenced by gene-gene interaction among PPARs genes. However, given the complexity pathogenesis of metabolic disease, it is unlikely that genetic variation of a single locus would provide an adequate explanation of inter-individual differences which results in diverse clinical syndromes. Thus, gene-gene interactions and gene-environment interactions associated with T2DM and MetS need future comprehensive studies.

Gene polymorphism of cytochrome P450 2C19*2 and clopidogrel resistance reflected by platelet function assays: a meta-analysis

BACKGROUND

The relationship between CYP2C19*2 gene polymorphism and clopidogrel resistance reflected by platelet function assays has been studied extensively in the past several years, while no clear conclusion can be drawn from the previous studies. To explore a more precise estimation of the relationship, a meta-analysis was conducted in the present study.

METHODS

The relevant studies were identified by searching PubMed, EMBASE, the Web of Science, Cochrane Collaboration Database, Chinese National Knowledge Infrastructure (CNKI), Wanfang Database, and China Biological Medicine (CBM) up to February, 2014. The meta-analysis was performed by the STATA 11.

RESULTS

Eight studies with a total of 2,331 subjects, including 1,066 patients with clopidogrel resistance and 1,265 patients without clopidogrel resistance were included. The pooled analysis showed that CYP2C19*2 gene polymorphism was probably associated with clopidogrel resistance (OR (95% CI): GA vs. GG: 2.10 (1.74-2.53); AA vs. GG: 3.05 (2.10-4.45); dominant model: 2.22 (1.85-2.65); recessive model: 2.33 (1.62-3.36)). No statistically significant difference was found in the analysis of the three subgroups. The statistical stability and reliability was also demonstrated by the sensitivity analysis and publication bias outcomes.

CONCLUSION

The meta-analysis suggests that CYP2C19*2 gene polymorphism may be associated with clopidogrel resistance.