Polymorphisms of the endothelial nitric oxide synthase (eNOS) gene have been implicated in various diseases, but their roles as risk factors in type 2 diabetes mellitus (T2DM) with regard to coronary artery disease (CAD) are largely unknown. Therefore, we investigated the association of the genotypes and haplotypes of eNOS polymorphisms in CAD with T2DM. A case-control study was performed to evaluate the genotypes and haplotypes of the eNOS polymorphisms (-786T>C, 4a4b and 894G>T) in 192 CAD patients and 196 controls. The same population was also re-organized upon the status of T2DM. The genotypes of eNOS -786T>C, 4a4b and 894G>T polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphism. We found that eNOS -786TC+CC and 4a4b+4a4a genotypes were significantly prevalent in the diabetic controls and the diabetic CAD patients compared to the non-diabetic controls or non-diabetic CAD patients, respectively. The frequency of the -786C-4a-894G haplotype was significantly greater in the diabetic CAD patients (p=0.001) and diabetic controls (p=0.023) compared to the non-diabetic controls, whereas the haplotype of -786T-4b-894G was less prevalent in the diabetic CAD patients compared to the non-diabetic controls (p=0.018). Significant associations of the genotypes and the haplotypes were consistently observed in the T2DM group compared to non-DM group, regardless of CAD status. Our finding suggests that the eNOS -786T>C and 4a4b polymorphisms and the -786C-4a-894G haplotype are risk factors for T2DM, whereas the haplotype of -786T-4b-894G has a protective effect against the development of T2DM.
coronary artery disease; endothelial nitric oxide synthase; haplotype; polymorphism; type 2 diabetes mellitus
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.
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).
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.
Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene (-786T >C and 894G >T) enhance endo-thelial 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.
coronary artery disease; coronary artery bypass graft surgery; eNOS -786T > C polymorphism, eNOS 894G > T polymorphism; smoking
Alterations of endothelial nitric oxide synthase (eNOS) enzyme activity via eNOS gene polymorphisms have been associated with significant cardiovascular morbidity and mortality. Both the thymidine to cytosine transition mutation (T−786→C) in the promoter region and the missense mutation in the exon 7 coding region of the eNOS gene (G894→T) have been associated with several cardiovascular disease states. We hypothesized that heart transplant recipients who carried at least one allele of either of the polymorphisms would have reduced myocardial tissue expression of eNOS measured in the explanted heart.
Genomic DNA was isolated from myocardial tissue samples obtained from 43 explanted human hearts using standard methods. Regions of the eNOS gene were amplified from genomic DNA with a polymerase chain reaction using specific primers. Protein expression of eNOS was measured by Western blot analysis. There was a statistically significant decrease in mean eNOS expression in samples containing at least one allele for the T−786→C promoter polymorphism (p = 0.04) compared to patients homozygous for the T allele. There was no change in eNOS expression associated with the G894→T exonic polymorphisms. Conclusions: Our data show in failing human myocardium that the T−786→C promoter polymorphism is associated with reduced eNOS expression whereas the G894→T polymorphism of exon 7 is not associated with change in either eNOS mRNA or protein expression. Reduced eNOS expression associated with the promoter polymorphism may contribute to the vascular, contractile, and autonomic responses to ventricular failure.
Nitric Oxide; Genetics; Cardiomyopathy; Pharmacogenetics
Hyperhomocysteinemia as a consequence of the MTHFR 677 C > T variant is associated with cardiovascular disease and stroke. Another factor that can potentially contribute to these disorders is a depleted nitric oxide level, which can be due to the presence of eNOS +894 G > T and eNOS −786 T > C variants that make an individual more susceptible to endothelial dysfunction. A number of genotyping methods have been developed to investigate these variants. However, simultaneous detection methods using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis are still lacking. In this study, a novel multiplex PCR-RFLP method for the simultaneous detection of MTHFR 677 C > T and eNOS +894 G > T and eNOS −786 T > C variants was developed. A total of 114 healthy Malay subjects were recruited. The MTHFR 677 C > T and eNOS +894 G > T and eNOS −786 T > C variants were genotyped using the novel multiplex PCR-RFLP and confirmed by DNA sequencing as well as snpBLAST. Allele frequencies of MTHFR 677 C > T and eNOS +894 G > T and eNOS −786 T > C were calculated using the Hardy Weinberg equation.
The 114 healthy volunteers were recruited for this study, and their DNA was extracted. Primer pair was designed using Primer 3 Software version 0.4.0 and validated against the BLAST database. The primer specificity, functionality and annealing temperature were tested using uniplex PCR methods that were later combined into a single multiplex PCR. Restriction Fragment Length Polymorphism (RFLP) was performed in three separate tubes followed by agarose gel electrophoresis. PCR product residual was purified and sent for DNA sequencing.
The allele frequencies for MTHFR 677 C > T were 0.89 (C allele) and 0.11 (T allele); for eNOS +894 G > T, the allele frequencies were 0.58 (G allele) and 0.43 (T allele); and for eNOS −786 T > C, the allele frequencies were 0.87 (T allele) and 0.13 (C allele).
Our PCR-RFLP method is a simple, cost-effective and time-saving method. It can be used to successfully genotype subjects for the MTHFR 677 C > T and eNOS +894 G > T and eNOS −786 T > C variants simultaneously with 100% concordance from DNA sequencing data. This method can be routinely used for rapid investigation of the MTHFR 677 C > T and eNOS +894 G > T and eNOS −786 T > C variants.
The purpose of this study was to evaluate the influence of polymorphisms of the eNOS gene on the clinical status of patients with normal and high tension glaucoma.
266 Polish Caucasian patients with primary open angle glaucoma were studied. Of the 266, 156 had normal tension glaucoma (NTG) and 110 high tension glaucoma (HTG). DNA material was isolated from peripheral venous blood using commercial kits. Real-time PCR reaction was used to amplify the promoter site of the endothelial nitric oxide synthase (eNOS) gene, including the single nucleotide polymorphism (SNP) site T-786C and part of the 7th exon of eNOS, including G894T SNP. Genotypes were determined with TaqMan SNP Genotyping Assays.
There were no significant differences in frequencies of the allelic variants of both polymorphisms. In G894T SNP, however, the wild GG form was more common in the HTG group. The SNP of the eNOS gene did not significantly influence the progression rate in either of the groups studied. There were no differences in variants of the eNOS gene regarding the necessity for and success of surgery and the progression of the disease. In the NTG group, no statistical correlation was observed between G894T, T786C polymorphism variants, and risk factors such as optic disc haemorrhages, optic disc notches, and peripapillary atrophy. Mean diastolic and systolic pressure during the day and night were lowest in NTG patients with the CC variant of the T786C polymorphism. No statistical correlation was observed between the G894T and T786C polymorphisms and capillaroscopic examination results.
Genotype frequencies are similar for both the eNOS G894T and T-786C polymorphisms in NTG and HTG patients. These polymorphisms do not correlate with risk factors and do not influence the state of the capillary system in NTG patients. Systolic blood pressure is lower in NTG patients with mutated alleles of both polymorphisms.
Background and Objective
Females with sickle cell disease (SCD) often show late onset of menarche. In transgenic sickle cell mouse, deficiency of gene encoding endothelial nitric oxide synthase (eNOS) has been reported to be associated with late onset of menarche. Thus to explore the possible association of eNOS gene polymorphism with age of onset of menarche in SCD females, 3 important eNOS gene polymorphisms- eNOS 4a/b, eNOS 894G>T (rs1799983) and eNOS-786 T>C (rs2070744) and plasma nitrite levels were tested among three groups of females- SCD late menarche, SCD early menarche and control females.
About 39 SCD females comprising of 18 SCD early menarche and 21 SCD late menarche groups were studied along with 48 control females. Genotyping of eNOS gene polymorphisms were done by PCR-RFLP and quantification of plasma nitrite level was performed by ELISA based commercial kits.
SCD late menarche females showed significantly higher prevalence and higher association of heterozygous genotypes, higher frequency of mutant alleles .4a., .T. and .C. as compared to that of control group and SCD early menarche group. The frequency of haplotype .4a-G-C. and haplotype .4b-G-C. (alleles in order of eNOS 4a/b, eNOS 894G>T and eNOS-786 T>C respectively) were found to be significantly high in SCD late menarche compared to combined groups of SCD early menarche and controls. SCD late menarche group had significantly low level of plasma nitrite concentration for all 3 eNOS gene polymorphisms as compared to controls and SCD early menarche females.
eNOS gene polymorphism may influence age of onset of menarche in SCD females.
Sorafenib may reduce endothelial nitric oxide synthase (eNOS) activity by inhibiting vascular endothelial growth factor receptors (VEGF-R), leading to a decrease in nitric oxide production. In the Italian multicenter ePHAS (eNOS polymorphisms in HCC and sorafenib) study, we analyzed the role of eNOS polymorphisms in relation to clinical outcome in patients with hepatocellular carcinoma (HCC) receiving sorafenib. Our retrospective study included a training cohort of 41 HCC patients and a validation cohort of 87 HCC patients, all undergoing sorafenib treatment. Three eNOS polymorphisms (eNOS -786T>C, eNOS VNTR 27bp 4a/b and eNOS+894G>T) were analyzed by direct sequencing or Real Time PCR in relation to progression-free survival (PFS) and overall survival (OS) (log-rank test). In univariate analysis, training cohort patients homozygous for eNOS haplotype (HT1:T-4b at eNOS-786/eNOS VNTR) had a lower median PFS (2.6 vs. 5.8 months, P < 0.0001) and OS (3.2 vs.14.6 months, P = 0.024) than those with other haplotypes. In the validation set, patients homozygous for HT1 had a lower median PFS (2.0 vs. 6.7 months, P < 0.0001) and OS (6.4 vs.18.0 months, P < 0.0001) than those with other haplotypes. Multivariate analysis confirmed this haplotype as the only independent prognostic factor. Our results suggest that haplotype HT1 in the eNOS gene may be capable of identifying a subset of HCC patients who are resistant to sorafenib.
hepatocellular carcinoma; endothelial nitric oxide synthase; single nucleotide polymorphisms; biomarkers; angiogenesis
Different allelic variants of endothelial nitric oxide synthase (eNOS) can have different effects on the development of certain forms of ischemic heart disease, depending on the specific human population. The frequency of the polymorphism T–786 → C in the promoter, G894→T in exon 7 and the variable number tandem repeat in intron 4 were assayed in patients with acute coronary syndrome compared with clinically healthy individuals in the Ukrainian population.
Polymerase chain reaction and restriction fragment length polymorphism analysis were used to detect the above mentioned variants of the eNOS gene in 221 patients with acute coronary syndrome and in 83 control subjects.
It was shown that the percentage of normal homozygotes, heterozygotes and pathological homozygotes for the T–786→C promoter polymorphism was 47.5%, 36.2% and 16.3%, respectively (controls: 48.2%, 45.8% and 6.0%; P<0.05 by χ2 test); for the G894→T polymorphism in exon 7, the percentages were 34.4%, 57.9% and 7.7%, respectively (controls: 28.9%, 67.5% and 3.6%; P>0.05); and, for the 4a/4b polymorphism in intron 4, the percentages were 64.7%, 31.2% and 4.1%, respectively (controls: 62.7%, 32.5% and 4.8%; P>0.05).
The C/C promoter variant of eNOS can be considered a risk factor for acute coronary syndrome in the Ukrainian population.
Acute coronary syndrome; Allelic polymorphism; Endothelial NO synthase
Nitric oxide (NO) has numerous functions in the kidney, including control of renal and glomerular hemodynamics, by interfering at multiple pathological and physiologically critical steps of nephron function. Endothelial NOS (eNOS) gene has been considered a potential candidate gene to diabetic nephropathy (DN) susceptibility. Endothelial nitric oxide synthase gene (eNOS-3) polymorphisms have been associated with DN, however some studies do not confirm this association. The analyzed polymorphisms were 4b/4a, T-786C, and G986T.
The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement was used in this report. Case–control studies that had diabetic patients with DN as cases and diabetic patients without nephropathy as controls, as well as that evaluated at least one of the three polymorphisms of interest were considered eligible. All studies published up until December 31st, 2012 were identified by searching electronic databases. Hardy-Weinberg equilibrium assessment was performed. Gene-disease association was measured using odds ratio estimation based on the following genetic contrast/models: (1) allele contrast; (2) additive model; (3) recessive model; (4) dominant model and (4) co-dominant model.
Twenty-two studies were eligible for meta-analysis (4b/a: 15 studies, T-786C: 5 studies, and G984T: 12 studies). Considering 4b/a polymorphism, an association with DN was observed for all genetic models: allele contrast (OR = 1.14, CI: 1.04-1.25); additive (OR = 1.77, CI: 1.37-2.28); recessive (OR = 1.77, CI: 1.38-2,27); dominant (OR = 1.12, CI: 1.01-1.24), with the exception for co-dominance model. As well, T-786C polymorphism showed association with all models, with exception for co-dominance model: allele contrast (OR = 1.22, CI: 1.07-1.39), additive (OR = 1.52, CI: 1.18-1.97), recessive (OR = 1.50, CI: 1.16-1.93), and dominant (OR = 1.11, CI: 1.01-1.23). For the G894T polymorphism, an association with DN was observed in allelic contrast (OR = 1.12, CI: 1.03-1.25) and co-dominance models (OR = 1.13, CI: 1.04-1.37).
In the present study, there was association of DN with eNOS 4b/a and T-786C polymorphism, which held in all genetic models tested, except for co-dominance model. G894T polymorphism was associated with DN only in allele contrast and in co-dominance model. This data suggested that the eNOS gene could play a role in the development of DN.
Chronic kidney disease (CKD) is associated with accelerated cardiovascular disease and heart failure. Endothelial nitric oxide synthase (eNOS) Glu298Asp single nucleotide polymorphism (SNP) genotype has been associated with a worse phenotype amongst patients with established heart failure and in patients with progression of their renal disease. The association of a cardiac functional difference in non-dialysis CKD patients with no known previous heart failure, and eNOS gene variant is investigated.
140 non-dialysis CKD patients, who had cardiac magnetic resonance (CMR) imaging and tissue doppler echocardiography as part of two clinical trials, were genotyped for eNOS Glu298Asp SNP retrospectively.
The median estimated glomerular filtration rate (eGFR) was 50mls/min and left ventricular ejection fraction (LVEF) was 74% with no overt diastolic dysfunction in this cohort. There were significant differences in LVEF across eNOS genotypes with GG genotype being associated with a worse LVEF compared to other genotypes (LVEF: GG 71%, TG 76%, TT 73%, p = 0.006). After multivariate analysis, (adjusting for age, eGFR, baseline mean arterial pressure, contemporary CMR heart rate, total cholesterol, high sensitive C-reactive protein, body mass index and gender) GG genotype was associated with a worse LVEF, and increased LV end-diastolic and systolic index (p = 0.004, 0.049 and 0.009 respectively).
eNOS Glu298Asp rs1799983 polymorphism in CKD patients is associated with relevant sub-clinical cardiac remodelling as detected by CMR. This gene variant may therefore represent an important genetic biomarker, and possibly highlight pathways for intervention, in these patients who are at particular risk of worsening cardiac disease as their renal dysfunction progresses.
Objective: To investigate the association between genetic polymorphism of T-786C in promoter region, 894G→T at exon 7 of endothelial nitric oxide synthase (eNOS) gene and osteoporosis (OP) disease. Method: The genotypes of 350 patients with osteoporosis and 350 healthy controls were detected by polymerase chain reaction (PCR) and DNA sequencing. The allele ratios and genotype distributions in the patients and controls were assessed using the Pearson χ2-test. Odds ratios (OR) with two tailed P-values and 95% confidence intervals (CI) were calculated as a measure of the association of the eNOS genotypes with OP. Result: the C allele distribution frequency of T-786C eNOS gene in OP group (8.5%) was significantly higher than that in control group (3.9%), relative risk (OR) of OP associated with the CC genotype was 2.68 (95% CI, 0.92 to 1.37). The T allele frequency of 894G→T at exon 7 in eNOS gene in OP group (11.5%) was also significantly higher than that in control group (5.2%), OR of OP associated with the TT genotype was 2.60 (all P<0.05). Conclusion: The analysis results indicated that both T-786C in promoter region and 894G→T at exon 7 of eNOS gene might be genetic predisposal factors of OP, these polymorphisms may be independently or synergic with other loci to have an impact on the incidence of OP.
T-786C; 894G→T; endothelial nitric oxide synthase gene; polymorphism; osteoporosis
Hantavirus infections are characterized by both activation and dysfunction of the endothelial cells. The underlying mechanisms of the disease pathogenesis are not fully understood. Here we tested the hypothesis whether the polymorphisms of endothelial nitric oxide synthase, eNOS G894T, and inducible nitric oxide synthase, iNOS G2087A, are associated with the severity of acute Puumala hantavirus (PUUV) infection.
Patients and Methods
Hospitalized patients (n = 172) with serologically verified PUUV infection were examined. Clinical and laboratory variables reflecting disease severity were determined. The polymorphisms of eNOS G894T (Glu298Asp, rs1799983) and iNOS G2087A (Ser608Leu, rs2297518) were genotyped.
The rare eNOS G894T genotype was associated with the severity of acute kidney injury (AKI). The non-carriers of G-allele (TT-homozygotes) had higher maximum level of serum creatinine than the carriers of G-allele (GT-heterozygotes and GG-homozygotes; median 326, range 102–1041 vs. median 175, range 51–1499 μmol/l; p = 0.018, respectively). The length of hospital stay was longer in the non-carriers of G-allele than in G-allele carriers (median 8, range 3–14 vs. median 6, range 2–15 days; p = 0.032). The rare A-allele carriers (i.e. AA-homozygotes and GA-heterozygotes) of iNOS G2087A had lower minimum systolic and diastolic blood pressure than the non-carriers of A-allele (median 110, range 74–170 vs.116, range 86–162 mmHg, p = 0.019, and median 68, range 40–90 vs. 72, range 48–100 mmHg; p = 0.003, respectively).
Patients with the TT-homozygous genotype of eNOS G894T had more severe PUUV-induced AKI than the other genotypes. The eNOS G894T polymorphism may play role in the endothelial dysfunction observed during acute PUUV infection.
Patients with diabetes are prone to develop cardiac hypertrophy and more susceptible to myocardial ischemia–reperfusion (I/R) injury, which are concomitant with hyperglycemia-induced oxidative stress and impaired endothelial nitric oxide (NO) synthase (eNOS)/NO signaling. Caveolae are critical in the transduction of eNOS/NO signaling in cardiovascular system. Caveolin (Cav)-3, the cardiomyocytes-specific caveolae structural protein, is decreased in the diabetic heart in which production of reactive oxygen species are increased. We hypothesized that treatment with antioxidant N-acetylcysteine (NAC) could enhance cardiac Cav-3 expression and attenuate caveolae dysfunction and the accompanying eNOS/NO signaling abnormalities in diabetes.
Control or streptozotocin-induced diabetic rats were either untreated or treated with NAC (1.5 g/kg/day, NAC) by oral gavage for 4 weeks. Rats in subgroup were randomly assigned to receive 30 min of left anterior descending artery ligation followed by 2 h of reperfusion. Isolated rat cardiomyocytes or H9C2 cells were exposed to low glucose (LG, 5.5 mmol/L) or high glucose (HG, 25 mmol/L) for 36 h before being subjected to 4 h of hypoxia followed by 4 h of reoxygenation (H/R).
NAC treatment ameliorated myocardial dysfunction and cardiac hypertrophy, and attenuated myocardial I/R injury and post-ischemic cardiac dysfunction in diabetic rats. NAC attenuated the reductions of NO, Cav-3 and phosphorylated eNOS and mitigated the augmentation of O2
−, nitrotyrosine and 15-F2t-isoprostane in diabetic myocardium. Immunofluorescence analysis demonstrated the colocalization of Cav-3 and eNOS in isolated cardiomyocytes. Immunoprecipitation analysis revealed that diabetic conditions decreased the association of Cav-3 and eNOS in isolated cardiomyocytes, which was enhanced by treatment with NAC. Disruption of caveolae by methyl-β-cyclodextrin or Cav-3 siRNA transfection reduced eNOS phosphorylation. NAC treatment attenuated the reductions of Cav-3 expression and eNOS phosphorylation in HG-treated cardiomyocytes or H9C2 cells. NAC treatment attenuated HG and H/R induced cell injury, which was abolished during concomitant treatment with Cav-3 siRNA or eNOS siRNA.
Hyperglycemia-induced inhibition of eNOS activity might be consequences of caveolae dysfunction and reduced Cav-3 expression. Antioxidant NAC attenuated myocardial dysfunction and myocardial I/R injury by improving Cav-3/eNOS signaling.
N-acetylcysteine; Diabetic cardiomyopathy; Myocardial ischemia–reperfusion injury; Caveolin-3; Diabetes
The purpose of this study was to analyse the effect of the T-786C polymorphism and intron 4 27 bp variable number tandem repeat(VNTR) eNOS markers for their potential association with Systemic Lupus Erythematosus(SLE), Hashimotos thyroiditis(HT) and Rheumatoid arthritis(RA) as well as to explore their effect on eNOS mRNA expression and nitrate production(NOx). Kuwaitis (n = 383) matched by age, gender and ethnicity were genotyped by fluorescent-labelled-restriction fragment length polymorphism (RFLP) and fragment analysis. Expression of eNOS mRNA was analysed using RT-PCR and sera from subjects were screened for NOx using ELISA. Analysis of the allelic frequency revealed a significant association of the 4b allele with susceptibility to SLE (p = 0.0092, OR = 1.76). The 4bb genotype was found to be associated with SLE (p = 0.0076, OR = 1.97) and HT (p = 0.05, OR = 1.81). Allelic and genotypic distribution did not differ between RA patients and healthy control subjects. The 4bb genotype resulted in reduced expression of eNOS mRNA in SLE, RA and HT, but only the reduction in HT was significant (p = 0.05). The 4ab genotype revealed a significant association with increased eNOS expression in HT (p = 0.03) and RA (p = 0.014) patients, and elevated NOx levels were detected in the autoimmune disease cohorts (p < 0.05) when compared to healthy control subjects. The T-786C SNP failed to show a significant association (p > 0.05) with SLE, HT, and RA patients. This study is the first to reveal a significant association between the 4bb genotype of the 27 bp VNTR and susceptibility to HT. The expression of eNOS is related to the number of 27 bp repeats, with heterozygous 4bb repeats showing a decrease in eNOS expression. eNOS – endothelial nitric oxide synthase.
eNOS; SLE; RA; HT
The T-786C, Glu298Asp, and 27 bp variable number of tandem repeats (27 bp-VNTR-a/b) polymorphsims of the endothelial nitric oxide synthase (eNOS) gene are thought to alter nitric oxide production and contribute to the development of vascular and renal disease risk. The objective of this study is to investigate whether these three polymorphisms examined previously by others are associated with cardiovascular and renal disease risk in Mexican Americans. Study participants (N = 848; 21 families) were genotyped for T-786C, Glu298Asp, and 27 bp-VNTR-a/b polymorphisms by PCR followed by restriction digestion. Association analyses were performed by a measured genotype approach implemented in the program SOLAR. Of the phenotypes (type 2 diabetes, hypertension, body mass index, waist circumference, total cholesterol, high density lipoprotein cholesterol, triglycerides, systolic and diastolic blood pressure, albumin to creatinine ratio (ACR), and estimated glomerular filtration rate) examined for association, the 27 bp-VNTR-a/b variant exhibited statistically significant association with ACR (P = 0.047) after accounting for the trait specific covariate effects. In addition, the promoter variant (T-786C) showed a significant association with triglycerides (P = 0.034) after accounting for covariate influences. In conclusion, the present study adds evidence to the role of eNOS candidate gene polymorphisms in modulating the risk factors related to cardiovascular-renal disease in Mexican Americans although the magnitude of the genetic effect is small.
eNOS; Genetic polymorphisms; Association analyses; ACR; Triglycerides; Mexican Americans
Endothelial dysfunction is a characteristic feature of diabetes and obesity in animal models and humans. Deficits in nitric oxide production by endothelial nitric oxide synthase (eNOS) are associated with insulin resistance, which is exacerbated by high fat diet. Nevertheless, the metabolic effects of increasing eNOS levels have not been studied.
The current study was designed to test whether overexpression of eNOS would prevent diet-induced obesity and insulin resistance.
Methods and Results
In db/db mice and in high fat-fed wild-type (WT) C57BL/6J mice, the abundance of eNOS protein in adipose tissue was decreased without significant changes in eNOS levels in skeletal muscle or aorta. Mice overexpressing eNOS (eNOS-TG mice) were resistant to diet-induced obesity and hyperinsulinemia, although systemic glucose intolerance remained largely unaffected. In comparison with WT mice, high fat-fed eNOS-TG mice displayed a higher metabolic rate and attenuated hypertrophy of white adipocytes. Overexpression of eNOS did not affect food consumption or diet-induced changes in plasma cholesterol or leptin levels, yet plasma triglycerides and fatty acids were decreased. Metabolomic analysis of adipose tissue indicated that eNOS overexpression primarily affected amino acid and lipid metabolism; subpathway analysis suggested changes in fatty acid oxidation. In agreement with these findings, adipose tissue from eNOS-TG mice showed higher levels of PPAR-α and PPAR–γ gene expression, elevated abundance of mitochondrial proteins, and a higher rate of oxygen consumption.
These findings demonstrate that increased eNOS activity prevents the obesogenic effects of high fat diet without affecting systemic insulin resistance, in part, by stimulating metabolic activity in adipose tissue.
Diabetes; mitochondria; metabolism; adipose tissue; cardiovascular disease; obesity; endothelial nitric oxide synthase
Nitric oxide (NO) synthesized by endothelial nitric oxide synthase (eNOS) plays an important role in regulation of endothelial function and in the control of blood pressure. However, the results from some studies on the association between three clinically relevant eNOS gene polymorphisms (G894T, T786C and intron 4b/a) and essential hypertension are unclear. We designed a case-control study to evaluate the influence of eNOS polymorphisms on target organ damage in 127 hypertensives and 67 normotensives. Clinical evaluation, biochemical parameters, Urinary Albumin Excretion (UAE) and echocardiogram were performed to characterize target organ damage. eNOS polymorphism were recognized by PCR method.
The distribution of eNOS genotypes was similar in hypertensives and normotensives but 4aa was present in the 2.5% of hypertensives and completely absent in normotensives. Subjects with 4bb, G894T, and T786C genotypes showed an increased prevalence of target organ damage. Moreover prevalence of G894T and introne 4 variants was significantly higher in hypertensives than in normotensives both with cardiovascular damage. Logistic regression analysis didn't show any association between eNOS polymorphisms, Body Mass Index (BMI), hypertension, gender and cardiovascular damage. Only the age (OR 1.11; IC 95% 1.06–1.18) was predictive of cardiovascular damage in our population.
Our results seem to indicate a lack of association with eNOS variants and cardiovascular damage onset.
Background: Nitric oxide (NO) is a major mediator in vascular biology, regulating regional blood flow. NO and the enzymes required for its production contribute to ischemia-reperfusion injury. The T-786C functional polymorphism in the promoter region substantially reduces promoter activity of the endothelial nitric oxide synthase (eNOS) gene and compromises endothelial NO synthesis.
Objective: To examine the association between T-786C (rs 2070744) single nucleotide polymorphism (SNP) in eNOS gene and the development of acute rejection in renal transplant patients.
Methods: 60 renal transplant recipients (30 with episodes of acute rejection (ARs) and 30 without rejection (non-ARs)), between June 2008 and March 2010, were included in this study. The polymorphism was determined by PCR-restriction fragment-length polymorphism analysis.
Results: The distribution of the genotypes were TT/TC/CC 60%, 33.4%, 6.6%, and 43%, 46.7%, 13.3% in ARs and non-ARs, respectively (p=0.28). The frequency of T-allele was 76.7% and 66.3%; and for C-allele was 66.6% and 33.3% in ARs and non-ARs, respectively (p=0.09). There were no significant associations between these polymorphisms and acute and chronic kidney allograft rejection.
Conclusion: We could not detect any significant association between polymorphism in T-786C of eNOS gene and the development of acute rejection.
Nitric oxide; Endothelial nitric oxide synthase; Polymorphism; Transplant; Acute rejection
Cardiovascular benefits from estradiol activation of nitric oxide endothelial production may depend on vascular wall and on estrogen receptor alpha (ESR1) and nitric oxide synthase (NOS3) polymorphisms. We have evaluated the microcirculation in vivo through nailfold videocapillaroscopy, before and after acute nasal estradiol administration at baseline and after increased sheer stress (postocclusive reactive hyperemia response) in 100 postmenopausal women, being 70 controls (healthy) and 30 simultaneously hypertensive and diabetic (HD), correlating their responses to PvuII and XbaI ESR1 polymorphisms and to VNTR, T-786C and G894T NOS3 variants. In HD women, C variant allele of ESR1 Pvull was associated to higher vasodilatation after estradiol (1.72 vs 1.64 mm/s, p = 0.01 compared to TT homozygotes) while G894T and T-786C NOS3 polymorphisms were connected to lower increment after shear stress (15% among wild type and 10% among variant alleles, p = 0.02 and 0.04). The G variant allele of ESR1 XbaI polymorphism was associated to higher HOMA-IR (3.54 vs. 1.64, p = 0.01) in HD and higher glucose levels in healthy women (91.8 vs. 87.1 mg/dl, p = 0.01), in which increased waist and HOMA-IR were also related to the G allele in NOS3 G894T (waist 93.5 vs 88.2 cm, p = 0.02; HOMA-IR 2.89 vs 1.48, p = 0.05). ESR1 Pvull, NOS3 G894T and T-786C polymorphism analysis may be considered in HD postmenopausal women for endothelial response prediction following estrogen therapy but were not discriminatory for endothelial response in healthy women. ESR1 XbaI and G894T NOS3 polymorphisms may be useful in accessing insulin resistance and type 2 diabetes risks in all women, even before menopause and occurrence of metabolic disease.
Nitric oxide is produced by endothelial nitric oxide synthase, and its production can be influenced by polymorphisms of the endothelial nitric oxide synthase gene. Because candidate genes responsible for susceptibility to ankylosing spondylitis are mostly unknown and available data suggest that there may be problems related to the nitric oxide pathway, such as endothelial dysfunction and increased asymmetric dimethylarginine, this study aimed to assess the association of common endothelial nitric oxide synthase gene polymorphisms with ankylosing spondylitis.
One hundred ninety-four unrelated Turkish ankylosing spondylitis patients and 113 healthy without apparent cardiovascular disease, hypertension or diabetes mellitus were included. All individuals were genotyped by PCR-RFLP for two single-nucleotide polymorphisms, namely 786T>C (rs2070744, promoter region) and 786 Glu298Asp (rs1799983, exon 7). Variable numbers of tandem repeat polymorphisms in intron 4 were also studied and investigated by direct electrophoresis on agarose gel following polymerase chain reaction analysis. The Bath ankylosing spondylitis metrology index of the patients was calculated, and human leukocyte antigen B27 was studied.
All studied polymorphisms satisfied Hardy-Weinberg equilibrium. Sex distributions were similar between the patient and control groups. No significant differences were found in the distributions of allele and genotype frequencies of the studied endothelial nitric oxide synthase polymorphisms between patients and controls. There were no correlations between endothelial nitric oxide synthase polymorphisms, disease duration, Bath ankylosing spondylitis metrology index or human leukocyte antigen B27.
The results presented in this study do not support a major role of common endothelial nitric oxide synthase polymorphisms in Turkish ankylosing spondylitis patients.
Ankylosing Spondylitis; Endothelial Nitric Oxide Synthase; Nitric Oxide; Inflammation; Atherosclerosis
DNA polymorphisms in endothelial nitric oxide synthase (eNOS) gene have been shown to be associated with constitutive eNOS expression and coronary artery disease (CAD). In the present study we explored the hypothesis whether genotype-dependent effects can be maintained in vitro during replication, or the effect is conditional on in vivo biological environments. Human umbilical vein endothelial cells (HUVEC) were collected and cultured from 89 normal deliveries of Mexican Americans. The cells were treated with or without cigarette smoking extracts (CSE) and genotypes of eNOS polymorphisms were determined by PCR. We measured the levels of eNOS by ELISA and its binding proteins including heat-shock protein 90 (Hsp-90) and caveolin-1 by Western blotting. The rare C allele for the promoter T786C polymorphism (0.2), and the rare 4 × 27-bp repeat allele in the intron 4 (0.30) were different from those reported in other populations. Yet, the rare T allele in the exon 7 (G894T polymorphism) was similar as others. After four passages in vitro, both the in-tron 4 and promoter polymorphisms maintained significant effects on eNOS mRNA levels in HUVECs (P < 0.05). However, the effects on eNOS protein and enzyme activity were less consistent. Although primary smokers had significantly lower eNOS protein levels (P < 0.05), the in vitro CSE treatment on cultured HUVECs only resulted in a significant reduction in NO levels as measured by the stable metabolites of nitrite/nitrate (P < 0.001). Neither Hsp-90 nor caveolin-1—important eNOS regulators—appears to mediate the genotype-smoking effects on eNOS expression although HUVECs did produce more Hsp-90 when exposed to CSE. Our study demonstrates that endothelial cells maintain genotype-dependent expression even after the deprivation of in vivo environment. However, the cigarette smoking–genotype interaction may require such in vivo conditions to be manifested.
Dilated Cardiomyopathy (DCM) is characterized by systolic dysfunction, followed by heart failure necessitating cardiac transplantation. The genetic basis is well established by the identification of mutations in sarcomere and cytoskeleton gene/s. Modifier genes and environmental factors are also considered to play a significant role in the variable expression of the disease, hence various mechanisms are implicated and one such mechanism is oxidative stress. Nitric Oxide (NO), a primary physiological transmitter derived from endothelium seems to play a composite role with diverse anti-atherogenic effects as vasodilator. Three functional polymorphisms of endothelial nitric oxide synthase (NOS3) gene viz., T-786C of the 5′ flanking region, 27bp VNTR in intron4 and G894T of exon 7 were genotyped to identify their role in DCM. A total of 115 DCM samples and 454 controls were included. Genotyping was carried out by PCR -RFLP method. Allelic and genotypic frequencies were computed in both control & patient groups and appropriate statistical tests were employed. A significant association of TC genotype (T-786C) with an odds ratio of 1.74, (95% CI 1.14 - 2.67, p = 0.01) was observed in DCM. Likewise the GT genotypic frequency of G894T polymorphism was found to be statistically significant (OR 2.10, 95% CI 1.34–3.27, p = 0.0011), with the recessive allele T being significantly associated with DCM (OR 1.64, 95% CI 1.18 - 2.30, p = 0.003). The haplotype carrying the recessive alleles of G894T and T-786C, C4bT was found to exhibit 7 folds increased risk for DCM compared to the controls. Hence C4bT haplotype could be the risk haplotype for DCM. Our findings suggest the possible implication of NOS3 gene in the disease phenotype, wherein NOS3 may be synergistically functioning in DCM associated heart failure via the excessive production of NO in cardiomyocytes resulting in decreased myocardial contractility and systolic dysfunction, a common feature of DCM phenotype.
Endothelial nitric oxide synthase (NOS3) activity and cigarette smoking significantly influence endothelial function. We sought to determine whether cigarette smoking modified the association between NOS3 polymorphisms and risk of coronary heart disease or stroke.
All 1085 incident coronary heart disease cases, all 300 incident ischemic stroke cases, and 1065 reference individuals from the Atherosclerosis Risk in Communities study were genotyped for the T-786C and E298D polymorphisms in NOS3. Using a case–cohort design, associations between genotype/haplotype and disease risk were evaluated by multivariable proportional hazards regression. Multiplicative scale interaction testing evaluated the influence of cigarette smoking history at baseline on these associations.
In Caucasians, association between E298D genotype and risk of coronary heart disease was significantly modified by current smoking status (interaction P = 0.013), with the highest risk observed in smokers carrying the variant D298 allele relative to nonsmokers carrying two E298 alleles (adjusted hazard rate ratio 2.07, 95% confidence interval 1.39−3.07). In African-Americans, association between T-786C genotype and risk of ischemic stroke was significantly modified by pack-year smoking history (interaction P = 0.037), with the highest risk observed in ≥ 20 pack-year smokers carrying the variant C-786 allele relative to < 20 pack-year smokers carrying two T-786 alleles (adjusted hazard rate ratio 4.03, 95% confidence interval 1.54−10.6).
An interaction between the E298D and T-786C polymorphisms in NOS3, cigarette smoking, and risk of incident coronary heart disease and ischemic stroke events appears to exist, suggesting a potential complex interplay between genetic and environmental factors and cardiovascular disease risk.
coronary artery disease; endothelial nitric oxide synthase; polymorphism; smoking; stroke
Hypertensive response to exercise (HRE) is known to be an adverse prognostic factor for future cardiovascular events and may be associated to endothelial dysfunction. Previous studies regarding endothelial nitric oxide synthase (eNOS) Glu298Asp polymorphism focused upon its relation to hypertension. In this study, we hypothesize that the polymorphism may be associated with inherent difference in endothelial response to exercise.
Patients and Methods
Two hundred sixty nine patients who underwent treadmill test were enrolled in this study; 77 patients (mean age 55.8 ± 9.4 years) had hypertensive response (peak systolic BP of ≥ 210mmHg in men and ≥ 190mmHg in women). Pulse wave velocity (PWV) was measured on 153 patients of them. The Glu298Asp exchange in exon 7 was determined by the methods of single base extension with amplifying primers and probes for TaqMan.
The percentages of the GG, GT and TT genotypes were 81.0, 18.6 and 0.4%, respectively. The presence of GT or TT genotype was independently associated with prevention of HRE when controlled for age, sex, baseline systolic BP and homeostatic model assessment (HOMA) index (OR = 0.35, p = 0.016). Subgroup analysis showed that preventive effect for HRE of T allele was significant in females (p < 0.001) and patients without insulin resistance (p = 0.009).
In our study, eNOS Glu298Asp polymorphism was significantly associated with HRE. This result suggests that the presence of T allele of the Glu298Asp polymorphism may be a favorable factor to in preventing HRE, especially in female and patients without insulin resistance.
Endothelial nitric oxide synthase; gene polymorphism; hypertension; hypertensive response to exercise