Association between the NOS3 (-786 T/C) and the ACE (I/D) DNA genotypes and early coronary artery disease

Association of Endothelial Nitric Oxide Synthase Gene Polymorphisms with Coronary Artery Disease in North Indian Punjabi Population

Nitric oxide (NO) a potent vasodilator synthesized by endothelial cells has anti-atherosclerotic properties and maintains vascular tone. It has been documented that its reduced bioavailability in vascular endothelium plays an important role in the development and progression of coronary artery disease (CAD). Therefore, we aimed to investigate the association of - 786 T > C and 894 G > T polymorphisms of eNOS with CAD. This study included 211 CAD patients and 260 controls of North Indian Punjabi population. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Logistic regression analysis revealed that the TC and CC genotypes of - 786 T > C were significantly associated with the higher risk of CAD (OR: 2.00, p = 0.001: OR: 4.63, p = 0.001, respectively). Similarly, the GT and TT genotypes of 894 G > T were found to be significantly associated with the higher risk of CAD (OR: 1.96, p = 0.001; OR: 4.54, p = 0.005, respectively). Moreover, the recessive model in  - 786 T > C (OR: 3.58, p = 0.002) and 894 G > T (OR: 3.62, p = 0.009) polymorphisms provided 3.6-fold increased risk for CAD. Furthermore, the CG, TT, and CT haplotypes were also associated with the increased risk of CAD (OR: 2.1, p = 0.001; OR: 2, p = 0.002; OR: 3.1, p = 0.001, respectively). In addition, the CC genotype of - 786 T > C and GT genotype of 894 G > T were significantly associated with higher levels of triglycerides (TG) and very low-density lipoproteins cholesterol (VLDL-C). The present study reported the association of - 786 T > C and 894 G > T polymorphisms of eNOS with CAD and abnormal lipid levels in North Indian Punjabi population.

Association of arsenic-induced cardiovascular disease susceptibility with genetic polymorphisms

Inorganic arsenic (iAs) exposure has been reported to have an impact on cardiovascular diseases (CVD). However, there is not much known about the cardiac tissue injury of CVD patients in relation to iAs exposure and potential role of single nucleotide polymorphisms (SNPs) of genes related to iAs metabolism, oxidative stress, endothelial dysfunction and inflammation which may play important roles in such CVD cases. In this dual center cross-sectional study, based on the exclusion and inclusion criteria, we have recruited 50 patients out of 270, who came from known arsenic-affected and- unaffected areas of mainly Chittagong, Dhaka and Rajshahi divisions of Bangladesh and underwent open-heart surgery at the selected centers during July 2017 to June 2018. We found that the patients from arsenic affected areas contained significantly higher average iAs concentrations in their urine (6.72 ± 0.54 ppb, P = 0.028), nail (529.29 ± 38.76 ppb, P < 0.05) and cardiac tissue (4.83 ± 0.50 ppb, P < 0.05) samples. Patients' age, sex, BMI, hypertension and diabetes status adjusted analysis showed that patients from arsenic-affected areas had significantly higher iAs concentration in cardiac tissue (2.854, 95%CI 1.017-8.012, P = 0.046) reflecting higher cardiac tissue injury among them (1.831, 95%CI 1.032-3.249, P = 0.039), which in turn allowed the analysis to assume that the iAs exposure have played a vital role in patients' disease condition. Adjusted analysis showed significant association between urinary iAs concentration with AA (P = 0.012) and AG (P = 0.034) genotypes and cardiac iAs concentration with AA (P = 0.017) genotype of AS3MT rs10748835. The AG genotype of AS3MT rs10748835 (13.333 95%CI 1.280-138.845, P = 0.013), AA genotype of NOS3 rs3918181 (25.333 95%CI 2.065-310.757, P = 0.002), GG genotype of ICAM1 rs281432 (12.000 95%CI 1.325-108.674, P = 0.010) and AA genotype of SOD2 rs2758331 (13.333 95%CI 1.280-138.845, P = 0.013) were found significantly associated with CVD patients from arsenic-affected areas. Again, adjusted analysis showed significant association of AA genotype of AS3MT rs10748835 with CVD patients from arsenic affected areas. In comparison to the reference genotypes of the selected SNPs, AA of AS3MT 10748835, AG of NOS3 rs3918181 and AC of rs3918188, GG of ICAM1 rs281432, TT of VCAM1 rs3176867, AA of SOD2 rs2758331 and GT of APOE rs405509 significantly increased odds of cardiac tissue injury of CVD patients from arsenic affected areas. The results showed that the selected SNPs played a susceptibility role towards cardiac tissue iAs concentration and injury among CVD patients from iAs affected areas.

Angiotensin-Converting Enzyme Gene D/I Polymorphism in Relation to Endothelial Function and Endothelial-Released Factors in Chinese Women

Many studies have investigated the relationship between angiotensin-converting enzyme (ACE) D/I polymorphism and cardiovascular disease or endothelial dysfunction; however, hardly any of these studies has taken aging or menopause into consideration. Furthermore, despite that many studies have examined the regulatory effects of endothelial-released factors (ERFs) on endothelial function, no study has evaluated the relationship between ERFs and endothelial function with respect to ACE D/I polymorphism and menopause status. To answer these questions, 391 healthy Chinese women over a wide range of ages (22-75 years) were enrolled and divided into pre-menopause group and post-menopause group. After ACE D/I genotype being identified, the women were then classified into either DI/II or DD genotype. Flow-mediated dilatation (FMD) of brachial endothelium and plasma levels of ERFs: nitric oxide (NO), endothelin-1 (ET-1), and angiotensin II (Ang II) were measured. The results showed that frequencies of ACE D/I genotypes were in accordance with the Hardy-Weinberg equilibrium, and the frequency of I allele was higher than D allele. In pre-menopause group, FMD was significantly higher in women of DI/II than DD (P = 0.032), and age-dependent in both genotypes (DD, P = 0.0472; DI/II, P < 0.0001). In post-menopause group, FMD was similar between women of DI/II and DD, and age-dependent only in women of DI/II (P < 0.0001). In pre-menopause group, Ang II level was significantly higher in women of DD than DI/II (P = 0.029), and FMD was significantly correlated with all ERFs in women of DD (NO, P = 0.032; ET-1, P = 0.017; Ang II, P = 0.002), but only with Ang II in women of DI/II (P = 0.026). In post-menopause group, no significant difference was observed in any ERF between women of DI/II and DD, and FMD was only significantly correlated with ET-1 in women of DD (P = 0.010). In summary, FMD in women of DI/II was superior to DD in pre-menopause and more age-dependent than DD in post-menopause, and FMD was closely associated with ERFs. In conclusion, Chinese women of DI/II seem to have lower risk than DD in pre-menopause, but similar risk as DD in post-menopause in developing cardiovascular disease.

Genetic association study between T-786C NOS3 polymorphism and essential hypertension in an Algerian population of the Oran city

BACKGROUND

Essential hypertension is an important risk factor for the development of cardiovascular disease. Important candidate genes such as NOS3 gene have been widely studied and reported to be associated with essential hypertension (HTN) in human populations.

AIM

We aim in this study to analyze the relationship between NOS3 -786T/C, a common genetic variant and HTN in a sample of the Algerian population of the Oran city.

METHODS

A case-control study has been performed in 154 subjects including 77 hypertensives and 77 normotensives. The recruitment of these subjects was done in local Health Centers of the city of Oran, West Algeria. HTN was defined as elevated systolic blood pressure SBD≥140  mmHg and or sustained diastolic blood pressure DBP≥90  mmHg, measured using an Omron^® Automatic BP Monitor - M-3W machine. Consents were obtained from all participants. Polymerase chain reaction (PCR) combined with restrictive fragment length polymorphism (RFLP) was used to genotype the NOS -786T/C variant.

RESULTS

The distribution of the allelic frequencies did not differ between cases and controls (OR = 1.48; 95%CI [0.94-2.32], P = 0.09). However, after adjustment with the age, sex, and body mass index, we observed significant association between NOS -786C allele and HTN status (OR = 2.08; 95%CI [1.18-3.66], P = 0.01).

CONCLUSION

Our results indicate that the C allele of the NOS3 gene is associated with increased risk of essential hypertension in this sample of the Algerian population of the Oran city. Further validation in larger samples is needed to confirm this finding.

The contribution of NOS3 variants to coronary artery disease: A combined genetic epidemiology and computational biochemistry perspective

Cardiovascular diseases, particularly coronary artery disease (CAD) and myocardial infarction, are the leading cause of death among people worldwide. CAD is exceedingly complex in its interplay of environment and genetics, with numerous genetic loci contributing to its heritability. Here, we aim at looking into the effects of the NOS3 c.894G>T and 27-bp VNTR polymorphisms on susceptibility to CAD in a population of Turkish Cypriots, at seeing whether these effects correlate with plasma lipid levels and at predicting the functional consequences of each polymorphism tested. A total of 50 subjects with CAD and 100 otherwise healthy subjects were included in the present case-control study. Genomic DNA was extracted from peripheral blood samples, and the two NOS3 polymorphisms were determined by restriction endonuclease analysis of PCR amplicons. Complementary methods of statistical analysis and computational modeling were employed accordingly to achieve the aims above. Our findings show that the 27-bp VNTR polymorphic locus, but not the c.894G>T polymorphic locus, is associated with CAD and that it may regulate NOS3 pre-mRNA splicing in a length-dependent manner. Overall, along with additional, yet-to-be ascertained susceptibility markers the 27-bp VNTR 4a/4b marker may be employed in risk stratification in community-level screening for CAD among Turkish Cypriots.

Analysis of Angiotensin Converting Enzyme, Endothelial Nitric Oxide Synthase & Serotonin Gene Polymorphisms among Atrial Septal Defect Subjects with and without Pulmonary Arterial Hypertension

Genetic polymorphisms are variations in DNA sequences which can influence either disease susceptibility, severity, or prognosis. Pulmonary arterial hypertension (PAH) is one of the complications that occurs in certain patients who have atrial septal defect (ASD). This study seeks to determine the association of gene polymorphisms with the pathogenesis of PAH in ASD patients. This study was conducted on 30 ASD patients with PAH, and 50 ASD patients who were not diagnosed with PAH. All respondents were Malay. Patients were selected based on stringent inclusion and exclusion criteria. Molecular analyses were done to detect the genetic polymorphisms of angiotensin converting enzyme (ACE I/D), serotonin transporter (5-HTTLPR), endothelial nitric oxide synthase (eNOS) G894T, and eNOS 4b/4a. The genotypes of these genetic polymorphisms were determined using conventional PCR and PCR-RFLP methods. The PCR products were analysed using agarose gel electrophoresis. Statistical analysis was done using SPSS Version 22. Clinical characteristics, such as the diameter of ASD, mean arterial pressure (MAP), and mean pulmonary artery pressure (mPAP) differed significantly (p < 0.05). Based on the statistical analysis, ACE I/D, eNOS G894T, and eNOS 4b/4a do not contribute to the progression of PAH amongst ASD patients (p > 0.05). However, the L allele of the 5-HTTLPR gene polymorphism may have an affect on the development of PAH in ASD patients (p < 0.05).

The Relation Between Endothelial Nitric Oxide Synthase Polymorphisms and Normal Tension Glaucoma

PURPOSE

We investigated whether polymorphisms of the endothelial NO synthase (eNOS) gene are associated with normal tension glaucoma (NTG). We also investigated whether the eNOS polymorphisms are associated with NTG subgroups [NTG with and without optic disc hemorrhage (DH)].

METHODS

A total of 251 patients with NTG and 245 healthy volunteers were enrolled in this study. DNA from peripheral blood leukocytes was extracted, and the genotypes of 4 polymorphisms (rs2070744, rs1549758, rs1799983, and rs2566514) in the eNOS gene were determined using restriction fragment length polymorphism and the SNaPshot method. The primary outcome was to investigate the relation between eNOS polymorphisms and NTG. The secondary outcome was to compare the frequencies of the polymorphic genotypes among the NTG subgroups. Bonferroni correction was used to adjust for type I error.

RESULTS

In all subjects, the genotype distribution was in accordance with Hardy-Weinberg equilibrium. None of the 4 polymorphisms showed any significant difference in the frequencies of alleles or genotypes between the NTG patients and controls. In the further analysis comparing the genotypic frequencies between NTG with DH and normal controls, the CC/CT genotype of rs2070744 was significantly associated with DH in NTG patients (genotypic association test, P-value=0.0041). On the multiple logistic regression analysis adjusted for covariates such as sex and age, the NTG with DH was associated with polymorphic genotypes of rs2070744 with a borderline significance (additive genetic model, P=0.0070).

CONCLUSIONS

Our results indicates that eNOS rs2070744 can be associated with NTG patients with DH. This finding suggests that the eNOS polymorphism may be a genetic risk factor in the development of DH in NTG patients.

A network-based method for mechanistic investigation of Shexiang Baoxin Pill's treatment of cardiovascular diseases

Shexiang Baoxin Pill (SBP), a traditional Chinese medicine formula, is commonly used to treat cardiovascular disease (CVD) in China. However, the complexity of composition and targets has deterred our understanding of its mechanism of action. Using network pharmacology-based approaches, we established the mechanism of action for SBP to treat CVD by analyzing protein-protein interactions and pathways. The computational results were confirmed at the gene expression level in microarray-based studies. Two of the SBP’s targets were further confirmed at the protein level by Western blot. In addition, we validated the theory that SBP’s plasma absorbed compounds play major therapeutic role in treating CVD.

The Effect of ACE I/D Polymorphisms Alone and With Concomitant Risk Factors on Coronary Artery Disease

BACKGROUND

Coronary artery disease (CAD), also known as atherosclerotic heart disease, is a leading cause of mortality and morbidity throughout the world. The role of insertion/deletion (I/D) polymorphisms of the angiotensin-converting enzyme (ACE) gene in the etiology of CAD remains to be more completely clarified. The aim of this study was to determine the role of the ACE I/D polymorphism in patients with CAD and to study the association together with traditional risk factors in assessing the risk of CAD.

METHODS

Our study population included 145 Tunisian patients with symptomatic CAD and a control group of 300 people matched for age and sex. All participants in the study were genotyped for the ACE I/D polymorphisms obtained by polymerase chain reaction amplification on genomic DNA.

RESULTS

Our analysis showed that the ACE D allele frequency ( P < 10^-3; odds ratio [OR] = 5.2; 95% confidence interval [CI] = 3.6-7.6) and DD genotype ( P < 10^-3; OR = 6.8; 95% CI = 4.4-10) are significantly more prevalent among patients with CAD than in controls and may be predisposing to CAD. We further found that the risk of CAD is greatly potentiated by several concomitant risk factors (smoking, diabetes, hypertension, dyslipidemia, and a family history of CAD).

CONCLUSION

The ACE D allele may be predictive in individuals who may be at risk of developing CAD. Further investigations of these polymorphisms and their possible synergisms with traditional risk factors for CAD could help to ascertain better predictability for CAD susceptibility.

Endothelial nitric oxide gene polymorphisms and their association with coronary artery disease in Tunisian population

OBJECTIVE

By releasing mediators, like nitric oxide (NO), vascular endothelium is considered so significant in the process of atherosclerotic . In fact, the major functions of NO consist in inhibiting the activation of platelet, relaxing the muscles (vascular and smooth ones), and modulating the growth and the migration of cells (vascular and smooth ones). Therefore, this process makes the endothelial nitric oxide synthase (NOS3) considerably important because it possesses atheroprotective activity. Polymophisms, rs1808593 (10G/T) as well as rs891512 (G24943A) within NOS3 gene, play major role in the coronary artery disease (CAD) development. The aim of the study is to evaluate the relationship between the 10G/T and G24943A polymorphisms and the CAD among Tunisian individuals.

METHODS

We included, in this survey, a set of 274 patients suffering from CAD together with 162 normotensive subjects. The PCR-RFLP was applied to analyze the polymorphism of intron 23 (10G/T) gene, while the ASA-PCR was used to analyze the intronic G24943A gene polymorphism. Overall and subgroup analyses were performed. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the association between NOS3 10G/T and G24943A polymorphisms as well as CAD risk. Statistical analysis was performed with SPSS V.10.

RESULTS

The genotype frequencies for G24943A polymorphism differed significantly between the CAD patients and the controls. The former had a frequency of 11.4% for the AA genotype, 34.7% for the GA genotype and 53.9% for the GG genotype. The latter had a frequency of only 2.5% for the AA genotype, 29.7% for the GA genotype and 67.7% for the GG genotype (χ2=7.62; OR=1.79; p=0.006). The CAD patient group showed a significantly-higher frequency of the A allele compared to the controls (0.28 vs. 0.16; χ2=15.20; p<0.001). The odds ratio of CAD for A vs. G allele frequency was statistically significant 1.99 (1.4-2.82) at 95% CI. The genotype distribution for the 3 investigated variants of 10G/T were not significantly different between CAD and control subjects (χ2=1.46; OR=1.72; p=0.22). Whereas, 10G/T has revealed barely allelic (χ2=4.45; OR=2.3; p=0.034) correlation with coronary artery disease Conclusion: The present study was designed so that there would be an association between the CAD and NOS3 polymorphism (G24943A). However, these results have proven that the polymorphism of 10G/T is not associated with CAD in the Tunisian population.

ASSOSIATION ANALYSYS OF 11 POLYMORPHISMS OF SNPS WITH ENDOTHELIUM DEPENDENT VASODILATATION IN CHILDREN WITH DIABETES MELLITUS TYPE 1

We have studied the association with the level of the endothelium dependent vasodilatation (EDVD) among 11 single nucleotide polymorphisms (SNPs) of 10 genes in 45 children suffering from diabetes mellitus type 1. Following polymorphisms have been studied: G894→T of the eNOS exon 7 and Т-786→С of the eNOS promotor, А1266→G of the Eln exon 16, Т-381→C of the NPPB promotor, І\D of the ACE, Arg60→His of the LMP2, Met235→Thr of the AGT, A1166→C of the ATR1, C-1562→T of the MMP9, C-1306→T of the MMP2, and С-8→G of the PSMA6. It was shown that children with genotypes G/T by eNOS (G894→T), G/G by Eln (А1266→G), C/C by NPPB (Т-381→C) and І/D by ACE genes have lower EDVD (Р<0,05) than patients with others allelic variants of these genes, and this does not depend on duration of the disease, level of glicated hemoglobin and initial diameter of a humeral (brachial) artery. The combination of the above-stated genotypes influences most significantly on EDVD decrease (r=0,61; Р<0,01), comparing to each genotype separately.

Association of endothelial nitric oxide synthase gene polymorphisms with coronary artery disease: an updated meta-analysis and systematic review

Several association studies of endothelial nitric oxide synthase (NOS3) gene polymorphisms with respect to coronary artery disease (CAD) have been published in the past two decades. However, their association with the disease, especially among different ethnic subgroups, still remains controversial. This prompted us to conduct a systematic review and an updated structured meta-analysis, which is the largest so far (89 articles, 132 separate studies, and a sample size of 69,235), examining association of three polymorphic forms of the NOS3 gene (i.e. Glu298Asp, T786-C and 27bp VNTR b/a) with CAD. In a subgroup analysis, we tested their association separately among published studies originating predominantly from European, Middle Eastern, Asian, Asian-Indian and African ancestries. The pooled analysis confirmed the association of all the three selected SNP with CAD in three different genetic models transcending all ancestries worldwide. The Glu298Asp polymorphism showed strongest association (OR range = 1.28–1.52, and P<0.00001 for all comparisons), followed by T786-C (OR range = 1.34–1.42, and P<0.00001 for all comparisons) and 4b/a, (OR range = 1.19–1.41, and P≤0.002 for all comparisons) in our pooled analysis. Subgroup analysis revealed that Glu298Asp (OR range = 1.54–1.87, and P<0.004 for all comparisons) and 4b/a (OR range = 1.71–3.02, and P<0.00001 for all comparisons) have highest degree of association amongst the Middle Easterners. On the other hand, T786-C and its minor allele seem to carry a highest risk for CAD among subjects of Asian ancestry (OR range = 1.61–1.90, and P≤0.01 for all comparisons).

Endothelial nitric oxide synthase (eNOS) 4b/a gene polymorphisms and coronary artery disease: evidence from a meta-analysis

A variety of studies have suggested that the 4b/a polymorphism in the endothelial nitric oxide synthase (eNOS) was associated with coronary artery disease (CAD) risk. However, the data remain conflicting. The aim of the present meta-analysis was to estimate the overall association between risk of CAD and eNOS 4b/a polymorphism. Case-control, cohort or cross-sectional studies evaluating the association between eNOS 4b/a polymorphism and CAD susceptibility were systematically identified in PubMed up to 31 October 2013. Pooled odds ratios (OR) and corresponding 95% confidence intervals (CIs) were calculated to assess the association in overall and subgroup analyses. A total of 10,617 cases and 8302 controls from 37 studies were included in the study. The results of overall analysis revealed significant positive associations between CAD risk and eNOS 4b/a polymorphism in homozygote comparisons (OR = 1.47, 95% CI = 1.16–1.87), heterozygote comparisons (OR = 1.14, 95% CI = 1.02–1.27) and dominant models (OR = 1.18, 95% CI = 1.06–1.33). In subgroup analyses, similar associations were identified in African individuals, as determined using population-based source subgroups and noted in small-and-moderate sample size subgroups (case sample size or control sample size <500). The current meta-analysis revealed that eNOS 4b/a polymorphisms could be a risk factor for developing CAD, particularly in African populations and population-based subgroups.

Polymorphisms of the NOS3 gene and risk of myocardial infarction in the Tunisian population

Controversial results regarding the association of eNOS gene (NOS3) polymorphisms with myocardial infarction (MI) have been reported. This study investigated the relationship of the -786T>C (rs2070744), 894G>T (rs1799983) and 4a4b polymorphisms of the NOS3 gene with the presence of MI in the Tunisian population. In addition, we also examined the association of NOS3 gene haplotypes with MI in Tunisian subjects. A total of 303 patients with MI and 225 controls were included in the study. The 894G>T and -786T>C single nucleotide polymorphisms were analyzed by PCR-RFLP, and 4a4b polymorphism just for PCR. There was significant linkage disequilibrium between the three NOS3 polymorphisms (p<0.0001). The genotype distribution and allele frequency of NOS3 4a4b, but not -786T>C and 894G>T, polymorphism was significantly different between MI patients and controls. The univariate logistic regression analysis showed a significant association of the 4a4b polymorphism and MI according to co-dominant, dominant and recessive models (co-dominant model OR: 4.38, 95%CI: 1.24-15.41; p=0.021, dominant model OR: 1.66, 95%CI: 1.14-2.42); p=0.007, and recessive model OR: 3.85, 95%CI: 1.10-13.47; p=0.035). The multivariate analysis, adjusted for traditional cardiovascular risk factors, revealed that the NOS3 4a4a genotype was an independent predisposing factor to MI, according to the models considered. In addition, a haplotype 7 (C-T-4a), (OR=12.05, p=0.010) was a risk factor of MI after controlling for classical risk factors. These finding suggest that the 4a4b polymorphism of the NOS3 gene was associated with MI in Tunisian patients.

Genetic variance in nitric oxide synthase and endothelin genes among children with and without endothelial dysfunction

Background

The presence of endothelial dysfunction (ED) constitutes an early risk factor for cardiovascular disease (CVD) in children. Nitric oxide (NO) and endothelin (EDN) are generated in endothelial cells and are critical regulators of vascular function, with ED resulting from an imbalance between these two molecules. We hypothesized that genetic variants in NO synthase and EDN isoforms and its receptors (EDNRA and EDNRB) may account for a proportion of the risk for ED in developing children.

Methods

Consecutive children (ages 5–10 years) were prospectively recruited from the community. Time to peak post-occlusive reperfusion (Tmax) was considered as the indicator of either normal endothelial function (NEF; Tmax < 45 sec) or ED (Tmax ≥ 45 sec). Lipid profiles, high sensitivity C-reactive protein (hsCRP), fasting glucose and insulin were assayed using ELISA. Genomic DNA from peripheral blood was extracted and genotyped for NOS1 (209 SNPs), NOS2 (122 SNPs), NOS3 (50 SNPs), EDN1 (43 SNPs), EDN2 (48 SNPs), EDN3 (14 SNPs), EDNRA (27 SNPs), and EDNRB (23 SNPs) using a custom SNPs array. Linkage disequilibrium was analyzed using Haploview version 4.2 software.

Results

The relative frequencies of SNPs were evaluated in 122 children, 84 with NEF and 38 with ED. The frequencies of NOS1 (11 SNPs), and EDN1 (2 SNPs) were differentially distributed between NEF vs. ED, and no significant differences emerged for all other genes. Significant SNPs for NOS1 and EDN1 SNPs were further validated with RT-PCR.

Conclusions

Genetic variants in the NOS1 and EDN1 genes appear to account for important components of the variance in endothelial function, particularly when concurrent risk factors such as obesity exist. Thus, analysis of genotype-phenotype interactions in children at risk for ED will be critical for more accurate formulation of categorical CVD risk estimates.

Polymorphisms in nitric oxide synthase and endothelin genes among children with obstructive sleep apnea

Background

Obstructive sleep apnea (OSA) is associated with adverse and interdependent cognitive and cardiovascular consequences. Increasing evidence suggests that nitric oxide synthase (NOS) and endothelin family (EDN) genes underlie mechanistic aspects of OSA-associated morbidities. We aimed to identify single nucleotide polymorphisms (SNPs) in the NOS family (3 isoforms), and EDN family (3 isoforms) to identify potential associations of these SNPs in children with OSA.

Methods

A pediatric community cohort (ages 5–10 years) enriched for snoring underwent overnight polysomnographic (NPSG) and a fasting morning blood draw. The diagnostic criteria for OSA were an obstructive apnea-hypopnea Index (AHI) >2/h total sleep time (TST), snoring during the night, and a nadir oxyhemoglobin saturation <92%. Control children were defined as non-snoring children with AHI <2/h TST (NOSA). Endothelial function was assessed using a modified post-occlusive hyperemic test. The time to peak reperfusion (Tmax) was considered as the indicator for normal endothelial function (NEF; Tmax<45 sec), or ED (Tmax≥45 sec). Genomic DNA from peripheral blood was extracted and allelic frequencies were assessed for, NOS1 (209 SNPs), NOS2 (122 SNPs), NOS3 (50 SNPs), EDN1 (43 SNPs), EDN2 (48 SNPs), EDN3 (14 SNPs), endothelin receptor A, EDNRA, (27 SNPs), and endothelin receptor B, EDNRB (23 SNPs) using a custom SNPs array. The relative frequencies of NOS-1,-2, and −3, and EDN-1,-2,-3,-EDNRA, and-EDNRB genotypes were evaluated in 608 subjects [128 with OSA, and 480 without OSA (NOSA)]. Furthermore, subjects with OSA were divided into 2 subgroups: OSA with normal endothelial function (OSA-NEF), and OSA with endothelial dysfunction (OSA-ED). Linkage disequilibrium was analyzed using Haploview version 4.2 software.

Results

For NOSA vs. OSA groups, 15 differentially distributed SNPs for NOS1 gene, and 1 SNP for NOS3 emerged, while 4 SNPs for EDN1 and 1 SNP for both EDN2 and EDN3 were identified. However, in the smaller sub-group for whom endothelial function was available, none of the significant SNPs was retained due to lack of statistical power.

Conclusions

Differences in the distribution of polymorphisms among NOS and EDN gene families suggest that these SNPs could play a contributory role in the pathophysiology and risk of OSA-induced cardiovascular morbidity. Thus, analysis of genotype-phenotype interactions in children with OSA may assist in the formulation of categorical risk estimates.

Polymorphisms of genes in nitric oxide-forming pathway associated with ischemic stroke in Chinese Han population

AIM

To investigate the association of polymorphisms in four critical genes implicated in the NO-forming pathway with ischemic stroke (IS) in a Chinese Han population.

METHODS

DNA samples of 558 IS patients and 557 healthy controls from Chinese Han population were genotyped using the Taqman(TM) 7900HT Sequence Detection System. Six SNPs (rs841, rs1049255, rs2297518, rs1799983, rs2020744, rs4673) of the 4 related genes (eNOS, iNOS, GCH1, and CYBA) in the NO forming pathway were analyzed using the SPSS 13.0 software package for Windows.

RESULTS

One SNP located in the intron of GCH1 (rs841) was associated with IS independent of the traditional cardiovascular risk factors in co-dominant and dominant models (P=0.003, q=0.027; P=0.00006, q=0.0108; respectively). Moreover, the combination of rs1049255 CC+CT and rs841 GA+AA genotypes was associated with significantly higher risk for IS after adjustments (OR=1.73, 95% CI: 1.27-2.35, P<0.0001, q<0.0001).

CONCLUSION

The data suggest that genetic variants within the NO-forming pathway alter susceptibility to IS in Chinese Han population. Replication of the present results in other independent cohorts is warranted.

Sexual dysfunction in male schizophrenia: influence of antipsychotic drugs, prolactin and polymorphisms of the dopamine D2 receptor genes

Aim: Sexual dysfunction induced by antipsychotic drug treatment is under investigated and under reported. This study aimed to determine the influence of genetic polymorphisms in the D2 dopamine receptor (DRD2) and endothelial nitric oxide synthase (eNOS) genes, and the possible role of blood prolactin concentrations on sexual function in schizophrenic patients. Materials & methods: Male remitted schizophrenic patients (n = 100), who were living with a sexual partner and receiving antipsychotic drug monotherapy for at least 6 months, were assessed for sexual and erectile dysfunction using the Arizona Sexual Experience Scale and the five-item version of the International Index of Erectile Function. Blood samples were taken for plasma prolactin determination and genotyped for four polymorphisms: DRD2 (-141C Ins/Del and Taq1A) and eNOS gene (G894T and T-786C). Results: The -141C Ins/Del, but not Taq1A, polymorphism of the DRD2 gene was significantly associated with sexual dysfunction with the del allele being less frequent in sexual dysfunction subjects. Neither of the eNOS polymorphisms, G894T or T-786C, was significantly associated with sexual or erectile dysfunction. Prolactin concentrations were significantly higher in patients with erectile dysfunction but did not reach significance in those with sexual dysfunction. Prolactin was also reduced in -141C Del allele carriers. The frequency and severity of sexual dysfunction in the patients receiving typical antipsychotics was significantly greater than those receiving risperidone or clozapine, while prolactin concentrations were significantly higher in subjects receiving risperidone compared with those receiving clozapine or typical antipsychotics. Conclusion: This is the first evidence indicating that antipsychotic drug treatment in men is associated with a variant in the DRD2 gene in which the -141C Del allele might be a protective factor. While this may, in part, be mediated by effects on prolactin, other factors are likely to contribute to the greater sexual dysfunction in patients receiving typical antipsychotics.

Original submitted 25 January 2011; Revision submitted 21 March 2011

Influence of endothelial nitric oxide synthase polymorphisms in psoriasis risk

Nitric oxide (NO) is a potent regulator of keratinocyte growth and differentiation that has been implicated in the pathogenesis of psoriasis (Ps). The NOS3 -786 T/C (SNP id rs2070744; http://www.ensembl.org ), intron 4 variable number tandem repeat (VNTR), and Glu298Asp (SNP id rs1799983) polymorphisms, have been associated with differences in NO plasma concentrations and with the risk of hypertension (HT) and ischemic cardiac disease. The aim of this study was to determine whether the above-mentioned NOS3 variants contributed to the risk of Ps, and were associated with the risk for HT and CAD in these patients. A total of 368 patients with chronic plaque Ps and 400 healthy controls were genotyped for the NOS3 -786 T/C, intron 4 VNTR, and Glu298Asp polymorphisms. Carriers of the -786 C allele were significantly more frequent among the patients (p < 0.001). Carriers of the 4-repeats allele (45 + 44 genotypes) were also more frequent a (p < 0.001). No significant difference was found for the Glu298Asp polymorphism. None of the NOS3 variants was associated with Ht and CAD in our population. In conclusion, NOS3 gene polymorphism would be risk factors for developing Ps.

Exploring epistatic relationships of NO biosynthesis pathway genes in susceptibility to CHD

AIM

To assess the epistatic relationships of nitric oxide (NO) biosynthesis pathway genes in susceptibility to coronary heart disease (CHD).

METHODS

A total of 2142 subjects enrolled in two case-control studies was genotyped for 7 single-nucleotide polymorphisms (SNP) within NO biosynthesis pathway genes using TaqMan assays. The association analyses were performed at both SNP and haplotype levels. Two-way SNP-SNP interactions and high-order interactions were tested using multiple unconditional logistic regression analyses and generalized multifactor dimensionality reduction (GMDR) analyses, respectively.

RESULTS

Two alleles (rs1049255*C and rs841*A) were identified that were significantly associated with increased risk of CHD after adjusting for all confounders (OR=1.21, 95% CI: 1.06-1.39, combined P=0.001, P(corr)=0.007 and OR=1.30, 95% CI 1.12-1.50, combined P<0.001, P(corr)<0.001, respectively). Significant two-way SNP-SNP interactions were found between SNP rs2297518 and these two significant polymorphisms, affecting the risk of CHD (P<0.001 for both). No significant high-order interactions were identified.

CONCLUSION

The results suggested that two-way SNP-SNP interactions of polymorphisms within NO biosynthesis pathway genes contribute to CHD risk.

Is Polymorphism within eNOS Gene Associated With the Late Onset of Myocardial Infarction? A Pilot Study

Introduction

Nitric oxide (NO) produced by endothelial nitric oxide synthase (eNOS) is a potent vasodilator. Several polymorphisms in the eNOS gene have been described, some of them being linked with the increased risk of cardiovascular disease, coronary heart disease (CHD), and coronary spasm.

Methods and Results

We studied 3 polymorphisms within the gene of eNOS (-786T/C, G10T, and 894 G/T) in patients with their first myocardial infarction (MI) younger than 45 years and in healthy volunteers. We found the relation between the occurrence of eNOS 894G allele and the Gensini score, which describes the severity of CHD ( P = .020).

Conclusions

The fact that first clinical manifestation of MI occurred in G carriers when the atherosclerotic plaque was much more advanced than in T carriers may suggest that wild-type genotype provided a better compensatory mechanisms due to NO synthesis and/or release. The polymorphisms within eNOS gene G10T, 894G/T, and −786T/C were not associated with the increased risk of MI.

Angiotensin-converting enzyme gene insertion/deletion polymorphism in Egyptian patients with myocardial infarction

Introduction. This work aimed to test the association of the angiotensin-converting enzyme gene insertion/deletion (I/D) polymorphism with myocardial infarction.

Subjects and methods. This study comprised 79 Egyptian myocardial infarction cases with a mean age of 54.4±9.9 years including 60 males and 19 females, plus 238 healthy unrelated individuals of nearly matched age and sex as a control group. For all subjects, DNA testing for the angiotensin-converting enzyme gene I/D polymorphism was done using PCR amplification for detection of both the D and I alleles followed by a second run PCR specific for the I allele for samples typed as DD in the first run.

Results. Cases had a higher frequency of DD (29.1%) and ID (62.0%) genotypes than II (8.9%) genotype, with a higher frequency of D allele than I allele (64.4% vs. 33.6%). Compared to controls, cases had a significantly higher frequency of ID genotype (62.0% vs. 47.5%, p<0.05).This was more apparent among cases in the low risk group (p=0.002) than in the high risk group (p=0.041).

Conclusion. The angiotensin-converting enzyme gene I/D polymorphism is probably a risk factor for ischaemic heart disease among Egyptian cases, particularly if integrated with other environmental and genetic risk factors.

Methylentetrahydrofolate reductase and nitric oxide synthase polymorphism in patients with atherosclerosis and diabetes

The development of the atherosclerosis is based on multifactorial causes. In addition to the traditional risk factors, gene polymorphisms can play a role in the disease. Therefore in this study we investigated whether the eNOS and MTHFR gene polymorphisms is associated with myocardial infarction and stroke in patients with or without diabetes. We have identified polymorphisms in the NOS 3 gene and one of these polymorphisms, Glu(298-->)Asp, was found to be a major risk factor for carotid artery disease and myocardial infarction. Our results indicate that the MTHFR G677T allele is significantly associated with MI. MTHFR 677 G/T genotyping may be of clinical importance as a prognostic and therapeutic marker, although further studies are needed to substantiate this hypothesis.

High plasmatic angiotensin-converting enzyme (ACE) activity is not correlated with training-induced left ventricular growth in ACE congenic rats

AIM

The aim of this study was to determine the influence of angiotensin-converting enzyme (ACE) genotype on left ventricular growth after endurance training, in ACE congenic rats with plasma ACE activity twice as high as the donor strain (LOU), thus mimicking the ACE I/D polymorphism observed in humans.

METHODS

LOU and congenic rats (n = 12) were submitted to an endurance training on a treadmill for 7 weeks, while similar LOU and congenic rats (n = 10) constituted the control groups. Blood pressure, skeletal muscle citrate synthase activity, plasma and left ventricular ACE activity were assessed, and echocardiography was performed before and after the training.

RESULTS

Angiotensin-converting enzyme plasmatic activity of congenic rats (188.2 +/- 26.6 in controls and 187.1 +/- 22.6 IU in trained rats respectively) was twofold that of the LOU strain (91.9 +/- 23.3 in controls, and 88.3 +/- 18.1 IU in trained rats respectively). After training, congenic and LOU rats showed a similar significant increase in citrate synthase activity (P < 0.05), and in the left ventricular mass/body mass ratio x 10(3): 3.7 +/- 0.3 and 3.6 +/- 0.6 in the trained congenic and LOU groups, respectively, vs. 3.0 +/- 0.1 and 2.9 +/- 0.2 in the control congenic and LOU groups respectively (P < 0.05). There was no significant correlation between ACE plasma activity and left ventricular mass in trained or untrained congenic rats.

CONCLUSION

We conclude that training-induced left ventricular growth is not associated with plasma ACE activity in congenic rats.

Simple detection of large InDeLS by DHPLC: the ACE gene as a model

Insertion-deletion polymorphism (InDeL) is the second most frequent type of genetic variation in the human genome. For the detection of large InDeLs, researchers usually resort to either PCR gel analysis or RFLP, but these are time consuming and dependent on human interpretation. Therefore, a more efficient method for genotyping this kind of genetic variation is needed. In this report, we describe a method that can detect large InDeLs by DHPLC (denaturating high-performance liquid chromatography) using the angiotensin-converting enzyme (ACE) gene I/D polymorphism as a model. The InDeL targeted in this study is characterized by a 288 bp Alu element insertion (I). We used DHPLC at nondenaturating conditions to analyze the PCR product with a flow through the chromatographic column under two different gradients based on the differences between D and I sequences. The analysis described is quick and easy, making this technique a suitable and efficient means for DHPLC users to screen InDeLs in genetic epidemiological studies.

Association of a 27-bp repeat polymorphism in intron 4 of endothelial constitutive nitric oxide synthase gene with myocardial infarction in Tunisian patients

BACKGROUND

Nitric oxide (NO) produced by endothelial nitric oxide synthase (eNOS) mediates endothelium-dependent vasodilatation and antithrombotic action. Controversial results regarding the association of eNOS gene (NOS3) polymorphisms with myocardial infarction (MI) have been reported. In the present study, we examined a possible association between a 27-base pair (bp) repeat polymorphism in intron 4 of the NOS3 gene and MI in a subgroup of the Tunisian population.

METHODS

A total of 310 Tunisian patients with MI and 250 healthy controls were included in the study. The NOS3 gene intron 4a4b variable number of tandem repeats polymorphism was analyzed by PCR.

RESULTS

A significant difference in genotype distribution and allele frequency was observed between patients and controls. Patients with MI had a frequency of 4.8% for the 4a4a genotype, 33.9% for the 4a4b genotype and 61.3% for the 4b4b genotype. Controls had a frequency of only 1.6% for the 4a4a genotype, 24.4% for the 4a4b genotype and 74.0% for the 4b4b genotype (chi2=11.81, p=0.003). The MI patient group showed a significant higher frequency of the 4a allele compared to controls (0.218 vs. 0.139; chi2=5.81, p=0.01).

CONCLUSIONS

In the present study, a significant association between the NOS34a/4b gene polymorphism (presence of 4a allele) and MI in the Tunisian population was found.

Association of endothelial nitric oxide synthase promoter region (T-786C) gene polymorphism with acute coronary syndrome and coronary heart disease

BACKGROUND

Nitric oxide (NO) is an endothelium derived relaxing factor (EDRF) which has an important role for regulating the heart-vessel physiology. The objective of this study was to evaluate the effects of the eNOS T-786C polymorphism on lipid parameters and the development of acute coronary syndrome (ACS) and coronary heart disease (CHD) for the first time in a Turkish study group. We have analyzed the genotype frequencies of the T-786C polymorphism of the eNOS gene in 10 ACS patients (5 men, 5 women), 20 CHD patients (14 men, 6 women), and 31 controls (10 men, 21 women), who were angiographically proven to have normal coronaries.

RESULTS

The demographic, biochemical and left ventricule systolic dysfunction data of the ACS, CHD patients and controls were analyzed as a function of eNOS T-786C genotypes. The eNOS gene T-786C polymorphism frequencies for T/T, C/T and C/C genotypes were respectively 10%, 40%, 50% in subjects with ACS; 75%, 20%, 5% in subjects with CHD and 67.7%, 25.8%, 6.5% in the control group. Significant difference was observed in genotype frequencies between the study groups for T-786C polymorphism (p = 0.001). The CC genotype frequency was found to be the most prevalent in ACS group in comparison to CHD and control groups (p = 0.001). TT was the most frequently observed genotype in both CHD patients and controls (p = 0.001). Left ventricule systolic dysfunction frequency was found to be highest in C/T genotype carriers (66.7%) in patients (ACS+CHD). None of the patients with LVSD were carrying the normal genotype (T/T). The eNOS T-786C polymorphism was not found to be effective over any analyzed lipid variable in patients (ACS+CHD). The HDL-cholesterol levels were found to be lower in CHD group were compared to controls (p < 0.01), whereas glucose and leucocyte levels of the ACS and CHD groups were both higher than controls (p < 0.001).

CONCLUSION

The significantly high frequency of eNOS -786C/C genotype in ACS patients than in those of controls, indicate the genotype association with ACS. The finding of significantly high frequency of T/T genotype in the CHD group, may support the relationship of CC genotype with ACS without CHD. The high frequency of the mutant (C/C) and heterozygous (C/T) genotypes found may be linked to left ventricule remodeling after MI.

Synergistic effect of angiotensin II type 1 receptor and endothelial nitric oxide synthase gene polymorphisms on arterial stiffness

Angiotensin II and nitric oxide belong to important factors in the functional and structural changes of vessel wall, leading to its increased stiffness. We investigated, whether common mutations of angiotensin II type 1 receptor (AGTR(1)) and endothelial nitric oxide synthase (eNOS) are associated with increased arterial stiffness. Two polymorphisms, A(1166)C of AGTR(1) and T(786)C of Enos, were estimated in a random, general population-based sample of 250 subjects. Arterial stiffness was measured using Sphygmocor as aortic (carotid-femoral) and peripheral (femoral-tibial) pulse wave velocities (PWV). Carriers of 3-4 mutant alleles from both polymorphisms, that is, homozygous for both mutations or homozygous for one and heterozygous for the second one, showed significantly higher peripheral PWV (17.92+/-2.40) than those with none or only 1-2 mutant alleles (12.37+/-0.51; P<0.003). Carriers of 3-4 mutant alleles had three times higher risk of having increased peripheral PWV (>or= 13.63 m s(-1), that is, in the top quartile) and this association remained significant after adjustment for potential confounders. No association was found between estimated genotypes and aortic PWV. In conclusion, combination of A(1166)C of AGTR(1) and T(786)C of eNOS mutations increased stiffness of muscular-type arteries.

Smoking-dependent and haplotype-specific effects of endothelial nitric oxide synthase gene polymorphisms on angiographically assessed coronary artery disease in Caucasian- and African-Brazilians

The nitric oxide produced by endothelial nitric oxide synthase (eNOS) plays a pivotal role in protecting the arterial wall from damages and atherosclerosis. The T-786C, the 27-bp repeat in intron 4, and the E298D eNOS gene polymorphisms were studied in 715 Brazilian patients (447 Caucasian- and 268 African-Brazilians) who underwent coronary angiography. The -786C frequency was increased in coronary artery disease (CAD) cases with significant lesions (> or =50% luminal obstruction) when compared with lesion-free controls; this difference was detected in smokers but not in nonsmokers, both in Caucasian- (p=0.011) and African-Brazilians (p=0.005). The interaction between -786C carriers and smoking was an independent CAD predictor (OR: 2.9, 95% CI: 1.4-5.9; p=0.003) in multiple logistic regression. The 298D mutation frequency was also higher among CAD cases (p=0.036) in African-Brazilian smokers, but this effect was not independent from other variables in the regression model. Though not associated with CAD, the 4-repeat allele combined with different T-786C alleles showed protective and susceptible effects in Caucasian-Brazilian smokers. The -786C/4-repeat/298E haplotype frequency was higher (p=0.020), whereas -786T/4-repeat/298E was lower (p=0.023) in these cases. These results showed a smoking-dependent effect of the T-786C eNOS polymorphism on CAD in both Caucasian- and African-Brazilians. Additionally, the haplotype analysis revealed different eNOS haplotypes associated with protection and susceptibility to the disease.

Influence of endothelial nitric oxide synthase gene polymorphisms (−786T>C, 4a4b, 894G>T) in Korean patients with coronary artery disease

INTRODUCTION

Endothelium-derived nitric oxide (NO) is synthesized from l-arginine by endothelial nitric oxide synthase (eNOS) encoded by the eNOS3 gene on chromosome 7. The effects of the eNOS polymorphisms with the risk of coronary artery disease are conflicting. In this study, we investigated the association of the eNOS genotypes with coronary artery disease in Koreans.

MATERIALS AND METHODS

A case-control study was performed to evaluate the association between the eNOS -786T>C, 4a4b, or 894G>T polymorphism and coronary artery disease. 147 consecutive patients with coronary artery disease and 222 healthy controls were recruited. The genotypes of eNOS -786T>C and 894G>T polymorphisms were determined by the polymerase chain reaction-restriction fragment length polymorphism analysis. The genotypes of a 27 bp insertion/deletion in intron 4 (eNOS 4a4b) were determined by the banding pattern on gel electrophoresis.

RESULTS

The eNOS -786T>C (odds ratio [OR]; 1.61, 95% confidence interval [CI]; 0.97-2.69), 894G>T (OR; 1.12, 95% CI; 0.65-1.92) and 4a4b (OR; 1.44, 95% CI; 0.87-2.39) polymorphisms were not an independent predisposition factor to coronary artery disease. However, a subgroup analysis adjusted with various cardiovascular risk factors confirmed positive association of the -786T>C polymorphism in CAD patients with hypertension and a smoking history and also a significant association of the intron 4 genotypes with a smoking history, but no significance has been found in the eNOS polymorphisms of 894G>T upon any risk adjustment. In this study we also found that the distribution of heterozygotes (-786TC, 894GT, and 4a4b) and variant homozygotes for the -786C, 894T, and intron 4a alleles of eNOS in Koreans were significantly lower than in Caucasian populations.

CONCLUSIONS

The present study demonstrates that polymorphisms of the eNOS -786T>C and 4a4b are associated with coronary artery disease with adjustments for cardiovascular risk factors in the Koreans.

AMI is associated with polymorphisms in the NOS3 and FGB but not in PAI-1 genes in young adults

BACKGROUND

We investigated the relationship between NOS3, FGB and PAI-1 polymorphisms and endothelial dysfunction and risk factors for acute myocardial infarction (AMI) in young adults.

METHODS

Endothelial function was measured by response to flow mediated vasodilation (FMV) and induced by nitrate (FMN). Biochemical parameters were measured by standard enzymatic methods and plasma total nitrate was analyzed by the NOA system. NOS3 (T-786C, G894T and intron 4A/B STR), FGB (C-148T and G-455A) and PAI-1 (4G/5G) polymorphisms were determined by PCR-RFLP.

RESULTS

Concentrations of total and LDL cholesterol, apo B, triglycerides, nitrate, PAI-1 and fibrinogen were higher and apo AI, HDL cholesterol and FMV were lower in AMI patients than in controls (p<0.001). PAI-1 (p<0.001) but not nitrate was higher in AMI patients with low response to FMV. NOS3 T-786C and FGB C-148T polymorphisms were associated with AMI (p<0.050). NOS3 T-786C was also related to hypertension (p=0.049). NOS3 intron 4A/B STR was associated with increased concentrations of total cholesterol and apo B. NOS3-786TT/894GT haplotype was associated with increased FMV (p=0.018) than the other haplotypes.

CONCLUSIONS

Our data suggest NOS3 and FGB polymorphisms are associated with AMI. NOS3 is also related to hypertension, endothelial dysfunction and variation on serum cholesterol in young adults with AMI.

Endothelial nitric oxide synthase gene polymorphisms and cardiovascular disease: a HuGE review

This review examines the association of a subset of endothelial nitric oxide synthase gene (NOS3) polymorphisms (Glu298Asp, intron 4, and -786T>C) with cardiovascular disease. The Glu298Asp polymorphism within exon 7 is the only common nonsynonymous variant. The variants have been associated with low plasma nitric oxide concentrations and reduced vascular reactivity; difficulties in measuring those phenotypes means that their functional role remains unclear. A large meta-analysis of NOS3 polymorphisms in coronary heart disease revealed per-allele odds ratios of 1.17 (95% confidence interval: 1.07, 1.28) for Glu298Asp, 1.17 (95% confidence interval: 1.07, 1.28) for -786T>C, and 1.12 (95% confidence interval: 1.01, 1.24) for intron 4. However, there was evidence that small studies with more striking results could affect the associations of the Glu298Asp and -786T>C polymorphisms with coronary heart disease. Associations of NOS3 polymorphisms with hypertension, preeclampsia, stroke, and diabetes remain uncertain. To date, no reliable gene-gene or gene-environmental interactions have been described. Use of these variants in predictive testing is unlikely to be useful, although the population attributable fraction could be substantial if the modest associations are causal. The need for large-scale genetic association studies using tagging polymorphisms is warranted to confirm or refute a role of the NOS3 gene in coronary heart disease.

Endothelial nitric oxide synthase G894T gene polymorphism in Chilean subjects with coronary artery disease and controls

BACKGROUND

Nitric oxide (NO) from the endothelium, produced by oxidation of l-arginine to L-citruline for the action at the endothelial nitric oxide synthase (eNOS), is considered an important atheroprotective factor. The Glu298Asp (G894T) polymorphic variant of the eNOS gene has been implicated in the development of coronary artery disease (CAD). We investigated the association between occurrence of CAD documented by angiography and the G894T polymorphism of the NOS3 gene in Chilean individuals.

METHODS

A total of 112 unrelated patients with diagnosis of CAD and 72 controls were included in this study. G894T gene polymorphism was analyzed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP).

RESULTS

The frequency of TT homozygous genotype for G894T polymorphism was 7% in CAD patients and 1% in the control group. However, the genotype distribution and allele frequencies were not significantly different between CAD and control subjects (P>0.05). Moreover, the odds ratio for CAD associated with the T variant failed to reach statistical significance (OR=1.5; 95% CI: 0.87-2.59, P>0.05).

CONCLUSION

These findings suggest that the G894T polymorphism of the eNOS gene was not associated with CAD in Chilean individuals.

Anti-inflammatory effects of atorvastatin: modulation by the T-786C polymorphism in the endothelial nitric oxide synthase gene

Statins produce cholesterol-independent, anti-inflammatory effects, which result at least in part from increased endothelial nitric oxide production. These effects may be modulated by polymorphisms in the endothelial nitric oxide synthase (eNOS) gene. Here, we examined whether the T-786C polymorphism of eNOS gene affects the concentrations of markers of atherosclerosis and inflammation (sCD40L, sVCAM-1, sICAM-1, sP-selectin, MCP-1, high sensitivity (hs)-CRP, MMP-2, MMP-9, and TIMP-1). We also studied whether atorvastatin-induced anti-inflammatory effects are modulated by this polymorphism. Healthy male volunteers (N=200), Caucasians, non-smokers, were genotyped for the T-786C polymorphism by restriction fragment length polymorphism. Subjects with TT or CC genotype received placebo for 14 days followed by 14 days of treatment with atorvastatin, 10mg/day p.o. The concentrations of inflammatory markers were measured with ELISA kits or by gelatin zymography. Serum cholesterol and LDL-cholesterol were significantly reduced after atorvastatin treatment in both genotype groups (P<0.05). No significant differences between genotype groups were found in the concentrations of the inflammatory markers after placebo. However, atorvastatin significantly reduced the concentrations of sCD40L, sVCAM-1, sP-selectin and MMP-9 in subjects with CC (but not TT) genotype (P<0.05). While atorvastatin decreased hs-CRP levels in both genotype groups (P<0.05), no significant effects were found on the concentrations of sICAM-1, MCP-1, pro-MMP-9, pro-MMP-2 and TIMP-1. These results suggest no effects for the T-786C polymorphism on the concentrations of inflammatory markers. However, this polymorphism modulates the anti-inflammatory effects of atorvastatin. These findings may be relevant for the primary prevention of cardiovascular events in subjects with CC genotype, who may be at increased cardiovascular risk and could benefit from treatment with statins.

The NOS3 (27-bp repeat, intron 4) polymorphism is associated with susceptibility to osteomyelitis

Cytokines generate nitric oxide (NO) in osteoblasts and neutrophils through the induction of NO synthase isoforms, endothelial (NOS3) and inducible (NOS2), thereby producing bone loss. In osteomyelitis (OM), a chronic infection of the bone, homozygosity for the NOS3 (27-bp repeat, intron 4 polymorphism) 4 allele was significantly more frequent among the 80 patients than in 300 healthy controls (p=0.044). No significant differences were found for other polymorphisms of the NOS genes such as NOS3, the promoter (-786T/C), and the missense change (E298D) in exon 7, and for NOS2, the G/A substitution at position 37498 in exon 22, the (CCTTT)(n), and (TAAA)(n) micro-satellites and the -954G/C in the promoter. Serum NO levels were significantly higher only in the OM patients homozygous for the NOS3 (27-bp repeat, intron 4 polymorphism) 4 allele, compared to controls. In the presence of bacteria or bacterial products, the neutrophils of these patients produced more NO. However, immunolabelling of osteoblasts for NOS3 in biopsy tissues did not correlate with the carriage of a determined NOS polymorphism but with the presence of bone inflammation. This is the first report of an association between a NOS3 polymorphism and the risk of developing OM.

Glyceryl trinitrate-induced angiotensin-converting enzyme (ACE) inhibition in healthy volunteers is dependent on ACE genotype

Evidence concerning the importance of angiotensin-converting enzyme (ACE) genotype in cardiovascular diseases is accumulating. The aim of this study was to investigate if nitric oxide (NO), generated from glyceryl trinitrate (GTN), affects human serum ACE activity in vivo, and if so, whether this effect was dependent on ACE genotype and (or) reflected in blood pressure reduction. A tablet containing 5 mg GTN was bucally administered for 5 minutes to 17 healthy volunteers. Blood pressure (BP) was recorded, and serum ACE activity, ACE genotype, and plasma cGMP was analyzed. GTN administration significantly reduced BP only in individuals with the deletion/deletion (DD) genotype. Sixty minutes after GTN administration, serum ACE activity was reduced in individuals with the insertion/insertion (II) and insertion/deletion (ID) genotypes, but not the DD genotype. Comparing the change in ACE activity over time between the genotypes resulted in the following: II vs. DD, p < 0.01; II vs. ID, p < 0.05; and ID vs. DD, p < 0.05. There was no significant difference in plasma cGMP content neither between the ACE genotypes nor before and after GTN administration. In conclusion, GTN inhibits serum ACE in vivo in individuals with the II and ID, but not the DD genotype.

Endothelial nitric oxide synthase and fractalkine chemokine receptor polymorphisms on angiographically assessed coronary atherosclerosis

BACKGROUND

The CX3CR1 is a fractalkine chemokine receptor expressed by leukocytes attracting them to the arterial wall inflammation. The endothelial nitric oxide synthase (eNOS) produces nitric oxide that acts on the vascular wall and circulating blood cells, lessening the inflammatory atherogenic damage. We determined if -786T > C and E298D eNOS and 745G>A CX3CR1 variants were associated with CAD risk and/or severity in Southern Brazilians of European descent.

METHODS

We investigated these polymorphisms in 358 patients who had undergone coronary angiography and 129 non-symptomatic controls by PCR followed by restriction analyses.

RESULTS

The 745 G > A CX3CR1 variant was not associated with CAD in this sample. Patients with significant CAD (coronary stenosis >or = 75%) presented higher frequencies of the eNOS -786C, but not of 298D allele than those observed among patients in whom significant CAD was ruled out by angiography (control group 1, p = 0.022) and non-symptomatic controls (control group 2, p < 0.001). The eNOS haplotypes derived from these 2 sites revealed that the frequency of haplotypes carrying the -786C allele (-786C/298D and -786C/298E) was increased and of the wild haplotype (-786T/298E) was decreased in patients with significant CAD (p = 0.003). After controlling for other classical risk factors carriers of haplotypes containing the -786C allele were at increased CAD risk (-786C/298D, OR = 2.95, p = 0.007; and -786C/298E, OR = 2.41, p = 0.030).

CONCLUSIONS

The -786T > C was the polymorphism associated with severe CAD in this study. Haplotype analyses can be extremely helpful in unraveling the influence of different markers within a gene.