ENOS gene variants and the risk of premature myocardial infarction

BACKGROUND: Endothelial nitric oxide synthase (eNOS) as well as nitric oxide play an important role in the regulation of cardiovascular function. There are limited and controversial data regarding the impact of polymorphisms of eNOS gene that is implicated in the vasoconstrictive properties of the endothelium in the pathogenesis of premature myocardial infarction (MI). OBJECTIVE: We examined whether two common polymorphisms of eNOS gene (G894T and T786C) are associated with the development of premature MI. METHODS: We recruited 107 patients with premature MI and compared them to 103 age- and sex- matched controls. All patients underwent coronary angiogram and were classified into the subgroup of patients with 'normal' or 'near normal' coronary arteries and the subgroup of patients with significant coronary artery disease (≥ 50% stenosis in lumen diameter of coronary arteries). The genetic polymorphisms of eNOS gene were assayed with polymerase chain reaction and reverse hybridization. RESULTS: Nineteen patients (17.8%) had 'normal' or 'near normal' coronary arteries. A significantly higher frequency of homozygosity for the 786C (32%) and the 894T (21%) alleles of the eNOS gene in patients who develop early MI in the setting of angiographically 'normal' or 'near normal' coronary arteries were found. CONCLUSIONS: Our data suggest that the T786C and the G894T genetic polymorphisms are associated with the development of MI in very young individuals, whose coronary arteries are characterized by very small atheromatic burden. © 2013 - IOS Press and the authors. All rights reserved

Evaluation of a reverse-hybridization StripAssay for the detection of genetic polymorphisms leading to acenocoumarol sensitivity

Acenocoumarol is mainly catabolized by CYP2C9 isoform of cytochrome P450 (CYP) liver complex and exerts its anticoagulant effect through the inhibition of Vitamin K Epoxide Reductase (VKOR). The most important genetic polymorphisms which lead to an impaired enzymatic activity and therefore predispose to acenocoumarol sensitivity, are considered to be CYP2C9*2 (Arg144Cys), CYP2C9*3 (Ile359Leu) and VKORC1-1639G>A, respectively. In this study we compared the results of the PGXThrombo StripAssay kit (ViennaLab Diagnostics,Vienna, Austria) with direct DNA sequencing and in house Restriction Fragment Length Polymorphisms (RFLP) for the detection of the aforementioned Single Nucleotide Polymorphisms (SNPs). The reverse hybridization StripAssay was found to be equally effective with RFLP and direct DNA sequencing for the detection of CYP2C9*2 and CYP2C9*3 polymorphisms, respectively. The comparison of the RFLP reference method with the reverse hybridization StripAssay for the detection of VKORC1-1639 G>A polymorphism showed that the reverse hybridization StripAsssay might misclassify some A/A homozygotes as heterozygotes. Optimization of the hybridization procedures may eliminate the extra low signal band observed in some samples at the reverse hybridization StripAssay and improve its diagnostic value. © Springer Science+Business Media B.V. 2009

Homozygosity of the TT methylenetetrahydrofolate reductase C677T genotype is an independent long-term predictor of cardiac death in patients with premature myocardial infarction

Background: Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism is the main genetic modulator of homocysteine. Data suggest a potential association of homozygosity for the TT MTHFR genotype with premature myocardial infarction (MI). We explored whether TT homozygosity is associated with long-term prognosis in patients with premature ST-segment elevation MI (STEMI). Methods: A total of 265 consecutive patients who had survived their first STEMI ≤35 years of age were followed for a median of 8 years (5–12). Primary endpoints were cardiac death and secondary endpoints were hospitalizations for acute coronary syndrome, myocardial revascularization, arrhythmic event or ischemic stroke. Serum lipids, homocysteine, folate levels were measured at baseline and all patients were also tested for the MTHFR C677T polymorphism. Results: During follow-up 14 patients died (cardiac death) [5.3%] while 84 (31.7%) met the secondary endpoints. In univariate Cox regression analysis TT homozygosity predicted the occurrence of cardiac death (Hazard ratio (HR): 4.071; 95% confidence interval (CI): 1.404–11.809, p =.010) but not the occurrence of secondary endpoints (HR: 0.877; 95% CI: 0.479–1.605, p =.669). TT homozygosity remained an independent predictor of cardiac death after adjustment for conventional risk factors (i.e., sex, diabetes mellitus, hypertension, family history of premature coronary artery disease [CAD]) [HR: 4.350; 95% CI: 1.472–12.856, p =.008]. The association also remained after adjustment for left ventricular ejection fraction or the presence of significant CAD. Conclusions: Homozygosity for the TT MTHFR is an independent long-term predictor of cardiac death in patients with premature STEMI. © 2021 Informa UK Limited, trading as Taylor & Francis Group

Lack of association of angiotensin-converting enzyme insertion/deletion polymorphism and myocardial infarction at very young ages

We examined whether angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism is associated with the development of myocardial infarction (MI) at ≤35 years of age. The study sample consisted of 201 patients with premature MI and 140 age- and sex-matched healthy individuals. No difference was found in the distribution of ACE genotypes between the patients and controls. A higher prevalence of the DD genotype among hypertensives was found compared with the non-hypertensive patients (62.5% vs 35.6%, p=0.01). ACE polymorphism is not associated with the development of premature MI and this might be due to the low prevalence of hypertension in young coronary patients