Association study of the CTH 1364 G>T polymorphism with coronary artery disease in the Greek population.

Background Cystathionine γ-lyase enzyme, which is encoded by the CTH gene, is responsible for hydrogen sulfide (H2S) production in the endothelium. The CTH 1364 G>T polymorphism may alter the CTH expression and H2S bioavailability, thus leading to atherosclerosis and coronary artery disease (CAD). We examined the potential association of the CTH 1364 G>T polymorphism with CAD. Methods The CTH 1364 G>T polymorphism was determined in 178 coronary artery bypass grafting (CABG) patients and 156 non-atherosclerotic controls of Greek Caucasian origin using the PCR-RFLP method. Results No significant difference in the frequency of the CTH 1364 G>T genotypes (p = 0.281) and alleles (p = 0.265) was found between the CABG patients and controls. After conducting stratification according to sex, analysis showed a numerical difference in the CTH 1364 TT genotype frequency in female participants that did not reach statistical significance (16.3% and 8.5% in the CABG and controls, respectively, p = 0.26). The frequency of the CTH 1364 TT genotype between the male CABG patients and controls did not differ (p = 0.507). Conclusions The CTH 1364 G>T polymorphism was not associated with CAD in the studied population. However, interestingly, a higher - if not significantly so - CTH 1364 TT genotype frequency was present in female CABG patients compared with female controls. Larger studies are necessary to conclude on the potential overall or gender-driven association between CTH 1364 G>T gene polymorphism and CAD.

Epigenetics-by-Sex Interaction for Coronary Artery Disease Risk Conferred by the Cystathionine γ-Lyase Gene Promoter Methylation.

Coronary artery disease (CAD) is a major global health burden whereby gene-by-environment-by-sex interactions play an important role. Coronary artery bypass graft (CABG) surgery involves patients with well-documented and severe CAD. Hence, the study of CAD in a context of the CABG surgery serves as an advantageous model for disease phenotype ascertainment and genetic association studies. We report here new observations from a case-control genetic association study on promoter methylation of the cystathionine γ-lyase (CTH) gene and its association with CAD. To the best of our knowledge, this is the first clinical study to show the DNA methylation status of the CTH promoter in relation to this clinical phenotype. CTH encodes for the hydrogen sulfide generating enzyme named CSE in the endothelium that is mechanistically highly relevant for CAD. In a sample of 334 subjects from Greece (178 cases with CAD and who underwent CABG, and 156 controls), CTH promoter methylation was analyzed using a SYBR Green-based quantitative methylation-specific polymerase chain reaction. We found increased methylation in CTH promoter in cases (19.1%) compared to controls (10.3%) (p = 0.024). Gene-by-sex analysis sustained the significant association in men (p = 0.032) but not in women (p = 0.884). By using multivariate analyses after controlling for potential confounders such as smoking, age, and gender, we found that increased CTH gene promoter methylation was associated with CAD in the total sample (odds ratio [OR] = 2.163, 95% confidence interval [CI] 1.038-4.506, p = 0.039) and in men (OR = 2.418, 95% CI 1.048-5.581, p = 0.039) but not in women (OR = 0.542, 95% CI 0.094-3.140, p = 0.495). These observations collectively warrant further precision medicine and biomarker research to examine the CTH methylation status as a putative epigenetic regulator of CAD risk in larger and independent samples.

Gene-gene interaction of µ-opioid receptor and GluR5 kainate receptor subunit is associated with smoking behavior in a Greek population: presence of a dose allele effect.

BACKGROUND: Components of nicotine reward system can potentially influence smoking behavior. The µ-opioid receptor (OPRM1) binds the endogenous opioid peptide ß-endorphin and mediates the reinforcing effects of nicotine, while the GluR5 kainate receptor subunit (encoded by GRIK1 gene), a binding site for known mediators of glutamate neurotransmission, potentially affects the glutaminergic system that is also indirectly implicated in the reward system. METHODS: In the present study, OPRM1 A118G and GRIK1 rs2832407C>A polymorphisms and their interactions were analyzed in 132 smoking initiators (SI) and 144 non-initiators (NI) of Greek origin, using the PCR-RFLP method. RESULTS: No differences were found in the genotype or allele distribution of OPRM1 A118G and GRIK1 rs2832407C>A between SI and NI. However, we found a significant interaction of OPRM1 A118G and GRIK1 rs2832407C>A genotypes associated with smoking initiation in a model adjusted for age, sex, BMI and type 2 diabetes mellitus (odds ratio=1.341, 95% CI 1.024-1.755, p=0.033). A dose effect of OPRM1 and GRIK1 variant alleles was present. Increased number of variant alleles (from 0 to 4) was associated with smoking initiation in the same adjusted model (odds ratio=1.537, 95% CI 1.030-2.293, p=0.036). CONCLUSIONS: Smoking phenotype is a complex interaction of genetic and environmental factors. In the present study, we have shown that gene-gene interaction of components of different systems associated with nicotine reinforcing effects, such as OPRM1 and GRIK1, rather than one gene polymorphism, is associated with smoking behavior.

New aspects on the metabolic role of intestinal microbiota in the development of atherosclerosis.

Gut microbiota remains a very interesting, yet largely unexplored ecosystem inside the human organism. The importance of this ecosystem for the physiology and the pathophysiology of the organism is being slowly unraveled. Recent studies reveal a connection between intestinal microbiota and atherosclerosis development. It seems that alterations in the function and composition of this bacterial population lead through complex mechanisms to a high risk for atherosclerosis. Although these mechanisms remain largely unknown, published studies show that microbiota can lead to atherosclerosis either by augmenting known risk factors or via other, more "direct" mechanisms. This review article summarizes the available literature regarding this matter.

Pharmacogenomics of oral antidiabetic medications: current data and pharmacoepigenomic perspective.

Type 2 diabetes mellitus (T2DM) is an increasingly prevalent disease. Several classes of drugs are currently available to treat T2DM patients; however, clinical response to these drugs often exhibits significant variation among individuals. For the oral antidiabetic drug classes of sulfonylureas, nonsulfonylurea insulin secretagogs, biguanides and thiazolidinediones, pharmacogenomic evidence has accumulated demonstrating an association between specific gene polymorphisms and interindividual variability in their therapeutic and adverse reaction effects. These polymorphisms are in genes of molecules involved in metabolism, transport and therapeutic mechanisms of the aforementioned drugs. Overall, it appears that pharmacogenomics has the potential to improve the management of T2DM and help clinicians in the effective prescribing of oral antidiabetic medications. Although pharmacogenomics can explain some of the heterogeneity in dose requirements, response and incidence of adverse effects of drugs between individuals, it is now clearly understood that much of the diversity in drug effects cannot be solely explained by studying the genomic diversity. Epigenomics, the field that focuses on nongenomic modifications that influence gene expression, may expand the scope of pharmacogenomics towards optimization of drug therapy. Therefore, pharmacoepigenomics, the combined analysis of genetic variations and epigenetic modifications, holds promise for the realization of personalized medicine. Although pharmacoepigenomics has so far been evaluated mainly in cancer pharmacotherapy, studies on epigenomic modifications during T2DM development provide useful data on the potential of pharmacoepigenomics to elucidate the mechanisms underlying interindividual response to oral antidiabetic treatment. In summary, the present article focuses on available data from pharmacogenomic studies of oral antidiabetic drugs and also provides an overview of T2DM epigenomic research, which has the potential to boost the development of pharmacoepigenomics in antidiabetic treatment.

Endothelial nitric oxide synthase gene polymorphisms -786T > C and 894G > T in coronary artery bypass graft surgery patients.

Polymorphisms in the endothelial nitric oxide synthase ( eNOS ) gene (- 786T > C and 894G > T ) enhance endothelial dysfunction and have been studied in relation to coronary artery disease (CAD). In the present study, we examined the association of the above polymorphisms with CAD, as well as with myocardial infarction (MI), hypertension, diabetes and smoking in CAD patients. Study subjects consisted of 154 consecutive coronary artery bypass graft (CABG) patients and 155 non-CAD controls. eNOS - 786T > C and 894G > T polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism. The estimated frequencies of the - 786C and 894T alleles did not differ between the two groups ( p = 0.46 and p = 0.84, respectively). The prevalence of eNOS polymorphisms was not associated with MI, hypertension or diabetes in CABG patients; however, we found that the 894TT genotype and 894T allele were significantly more frequent in current/past smoker CABG patients (16.7 per cent and 39.6 per cent, respectively) compared with never smoker CABG patients (6.1 per cent and 24.4 per cent, respectively) ( p = 0.01 and p < 0.01, respectively). We found no association of eNOS - 786C and 894T variant alleles with CAD; however, within CABG patients, a gene-environment interaction was found between the eNOS 894T allele and smoking.

Renin-angiotensin-aldosterone system gene polymorphisms in coronary artery bypass graft surgery patients.

INTRODUCTION: Candidates for coronary artery bypass grafting (CABG) represent a group of patients with well documented, severe coronary artery disease (CAD). Genetic polymorphisms of renin-angiotensin-aldosterone system (RAAS) components have been associated with CAD. We examined the association of polymorphisms of angiotensin-converting enzyme (ACE), angiotensinogen (AGT), and angiotensin II type 1 receptor (AT(1) receptor) with severe CAD in CABG patients. MATERIALS AND METHODS: One hundred and fifty-four CABG patients and 155 non-CAD controls were included in the study. Established PCR methods were used for genotyping of AGT M235T, AGT T174M, AT(1) receptor A1166C, and ACE I/D polymorphisms. Cumulative effect of analysed polymorphisms was assessed by calculation of each individual's RAAS gene score (addition of 0.5 points for each variant allele and then calculating the sum for all four polymorphisms). RESULTS: No association between AGT M235T, AGT T174M, ACE I/D and AT(1) receptor A1166C polymorphisms and CAD was observed. Within CABG patients, the frequency of homozygous AGT 235TT genotype was higher in hypertensive compared to normotensive CABG patients (21.7% vs. 6.3%, p=0.03). RAAS gene score did not differ between CABG patients and non-CAD controls. CONCLUSIONS: There is no association of the analysed RAAS polymorphisms with severe CAD in CABG patients. However, within these patients, an association was found between AGT 235TT genotype and hypertension.

Association of polymorphisms of the serotonergic system with smoking initiation in Caucasians.

BACKGROUND: The serotonergic system may be implicated in susceptibility to nicotine dependence as nicotine increases 5-hydroxytryptamine (5-HT) release in brain and symptoms of nicotine withdrawal may be modulated by diminished serotonergic neurotransmission. We examined the association of polymorphisms of genes involved in release and receptor function of 5-HT with cigarette smoking initiation in subjects of Caucasian origin. METHODS: 5-HTTLPR polymorphism of the 5-HT transporter gene and -759C/T (rs3813929) and -697G/C (rs518147) polymorphisms of the 5-HT(2C) receptor gene were analyzed in 172 smoking initiators and 254 non-initiators, using PCR-RFLP method. Smoking behavior was assessed with a questionnaire about tobacco use. RESULTS: We found no differences in the frequency of the 5-HTTLPR genotypes between smoking initiators and non-initiators. However, the frequency of 5-HT(2C) -759T allele was significantly higher in non-initiators than smoking initiators (29.5% vs 16.3%, p=0.002) and the same was true for 5-HT(2C) -697C allele carriers (48.8% vs 34.9%, p=0.004). Sex-dependent analysis revealed that these increased frequencies of -759T and -697C allele carriers were present only in males. No association was observed between any quantitative measures of smoking and these three polymorphisms. CONCLUSIONS: 5-HTTLPR polymorphism was not associated with smoking initiation in either male or female subjects. However, significant association was found between 5-HT(2C) receptor gene polymorphisms and smoking initiation in male Caucasian subjects.

Pharmacological characterization in vitro of EP2306 and EP2302, potent inhibitors of squalene synthase and lipid biosynthesis.

We investigated the effects of EP2306 and EP2302, two novel 2-biphenylmorpholine derivatives, on squalene synthase activity in rabbit and human liver microsomes, lipid biosynthesis, low-density lipoprotein (LDL) receptor expression and LDL protein uptake as well as apoB secretion in HepG2 cells. Both EP2306 and EP2302 inhibited squalene synthase activity dose-dependently. In rabbit liver microsomes, the IC50 values were 33 microM for EP2306 and 0.6 microM for EP2302 whereas in human liver microsomes, they were 63 microM for EP2306 and 1 microM for EP2302. Both EP2300 compounds inhibited cholesterol production by HepG2 cells dose dependently with IC50 values of 13.3 microM for EP2306 and 3 microM for EP2302. Furthermore, both EP2300 compounds and simvastatin significantly reduced triglyceride synthesis and apoB secretion and increased LDL receptor expression and LDL uptake in HepG2 cells. In summary, we have shown that EP2300 compounds are potent inhibitors of squalene synthase activity in rabbit and human liver microsomes and also they are effective inhibitors of cholesterol and triglyceride biosynthesis in HepG2 cells. These results suggest that EP2306 and EP2302 might prove to be useful for lipid-lowering and treatment of atherosclerosis in vivo.

Association of hyperandrogenemic and metabolic phenotype with carotid intima-media thickness in young women with polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS), a common endocrinopathy of women of reproductive age, is associated with the early appearance of multiple risk factors for cardiovascular disease, such as abdominal obesity, dyslipidemia, and diabetes mellitus. However, premature atherosclerosis of the carotid artery has not yet been demonstrated in young women with PCOS. Measurement of carotid intima-media thickness (IMT) is considered an easy and reliable index of subclinical atherosclerosis, which is predictive of subsequent myocardial infarction and stroke. To evaluate the cardiovascular risk of PCOS and the participation of the hyperandrogenemic and metabolic pattern, we measured carotid IMT by B-mode ultrasound as well as hormonal and several cardiovascular disease-associated parameters in 75 young women with PCOS and 55 healthy, age- and body mass index-matched women. The PCOS women had significantly increased carotid IMT (0.58 vs. 0.47 mm, P < 0.001) and abdominal adiposity; higher levels of androgens, insulin, homeostasis model assessment score of insulin sensitivity, and total and low-density lipoprotein-cholesterol; and significantly lower levels of SHBG and high-density lipoprotein-cholesterol. In the studied population (n = 130), PCOS status, age, body mass index, and parental history of coronary heart disease were strong positive predictors of carotid IMT, whereas dehydroepiandrosterone sulfate was a strong negative predictor. In PCOS patients lower delta4-androstenedione and high-density lipoprotein-cholesterol levels were additionally strong positive predictors of carotid IMT, whereas in control women only total cholesterol was the additional positive predictor of carotid IMT. In conclusion, young women with PCOS have an early increase of cardiovascular risk factors and greater carotid IMT, both of which may be responsible for subclinical atherosclerosis. The hyperandrogenemic phenotype of the syndrome may attenuate the consequences of the dysmetabolic phenotype on the vascular wall.