Endothelial Nitric Oxide Synthase Genotypes Research Articles

Endothelial nitric oxide synthase genotype is associated with pulmonary hypertension severity in left heart failure patients.

The biological mechanisms behind the development of pulmonary hypertension in the setting of left heart failure (HF-PH), including combined pre- and post-capillary pulmonary hypertension (Cpc-PH), remains unclear. This study aimed to use candidate polymorphisms in nitric oxide synthase (NOS) genes to explore the role of NOS in HF-PH. DNA samples from 118 patients with HF-PH were genotyped for the NOS3 rs1799983 and NOS2 rs3730017 polymorphisms. A multiple regression model was used to compare hemodynamic measurements between genotype groups. Patients with the T/T genotype at rs1799983 possessed a nearly 10 mmHg increased transpulmonary gradient (TPG) compared to those with other genotypes (P = 0.006). This finding was replicated in an independent cohort of 94 HF-PH patients (P = 0.005). However, when tested in a cohort of 162 pre-capillary pulmonary arterial hypertension patients, no association was observed. In a combined analysis of both HF-PH cohorts, mean pulmonary artery pressure (mPAP), diastolic pulmonary gradient (DPG), and CpcPH status were also associated with rs1799983 genotype (P = 0.005, P = 0.03, and P = 0.02, respectively). In patients with HF-PH, the NOS3 rs1799983 polymorphism is associated with TPG, and potentially mPAP and DPG as well. These findings suggest that endothelial NOS (encoded by NOS3) may be involved in the pulmonary vascular remodeling observed in Cpc-PH and warrants further study.

Relation between Endothelial Nitric Oxide Synthase Genotypes and Oxidative Stress Markers in Larynx Cancer.

Nitric oxide synthase (eNOS/NOS3) is responsible for the endothelial synthesis of nitric oxide (NO•). G894T polymorphism leads to the amino acid substitution from Glu298Asp that causes lower NOS3 activity and basal NO• production in NOS3 894T (298Asp) allele carriers compared with the GG homozygotes. NO• acts as an antioxidant protecting against Fenton's reaction which generates highly reactive hydroxyl radicals. Allelic variation of NOS3 may influence an individual's risk of laryngeal cancer (LC). In the current study we have examined the possible relationship between NOS3 G894T genotypes and various systemic oxidative damage markers such as protein carbonyl, advanced oxidation protein products, Cu, Zn-superoxide dismutase, thiol group fractions, and lipid hydroperoxides in LC patients. Genotyping was carried out by PCR-RFLP. In LC patients with TT genotype, Cu, Zn-superoxide dismutase activities and nonprotein thiol levels were significantly higher than the controls. In patients with GT and GG genotype, high levels of lipid hydroperoxides showed statistical significance when compared to controls. Our results indicate a potential relationship among G894T polymorphism of NOS3, and impaired redox homeostasis. Further studies are required to determine the role of NOS3 gene polymorphism and impaired plasma redox homeostasis.

Association of Endothelial Nitric Oxide Synthase Gene Polymorphisms With Acute Rejection in Liver Transplant Recipients.

Polymorphisms of the endothelial nitric oxide synthase gene have been associated with altered endothelial nitric oxide synthase activity. The purpose of this study was to investigate the relation between endothelial nitric oxide synthase -786T/C and 894G/T polymorphism and their haplotypes on the occurrence of acute rejection episodes in liver transplant recipients. We conducted a case control study in which 100 liver transplant recipients and 100 healthy controls were recruited from Shiraz Transplant Center. The patients used triple therapy including tacrolimus, mycophenolate mofetil, and prednisolone for immunosuppression maintenance. DNA was extracted from peripheral blood and endothelial nitric oxide synthase polymorphisms were determined by polymerase chain reaction and restriction fragment length polymorphism. Patients included 60 men and 40 women (mean age, 32.35 ± 10.2 y). There was a significant association of endothelial nitric oxide synthase 894G/T and acute rejection episode. The GT* gen-otype and acute rejection episodes had a significant association (odds ratio, 2.42; 95% confidence interval, 0.97-6.15; P = .03). The GG and GT* genotype and T* allele frequency were significantly different between patients and control subjects (P = .001). Haplotype TT* was higher in recipients than control subjects (odds ratio, 2.17; 95% confidence interval, 1.12-4.25; P = .01). Haplotype TG was higher in the control group (odds ratio, 0.62; 95% confidence interval, 0.40-0.96; P = .02). Our results suggest a relation between different endothelial nitric oxide synthase geno-types and risk of acute rejection episodes. However, further study is necessary to determine genetic susceptibility for transplant patients.

Effect of Endothelial Nitric Oxide Synthase Genotype on Outcomes after Experimental Thromboembolic Stroke

Acute ischemic stroke is the one of leading causes of morbidity and mortality in the U.S. African Americans have higher risk of stroke incidence and death that is associated with endothelial dysfunction and reduced bioavailability of nitric oxide. We propose that endothelial nitric oxide synthase knockout (eNOS−/−) or heterozygote (eNOS+/−) mice may be a suitable model of African American stroke.MethodsThe eNOS−/− and C57BL/6J mice were crossed to obtain eNOS+/−MAT and eNOS+/−PAT offspring (30±3 weeks; 13 mice/group). Embolic stroke was initiated by injection of a thrombus to the right middle cerebral artery. Cerebral blood flow was recorded to confirm occlusion. At 24 hours, the neurological status and brains were analyzed.ResultseNOS−/− mice were characterized by small litter size and high pup mortality. The final body weight was similar among eNOS+/−MAT, eNOS+/−PAT, and eNOS−/− mice, but significantly lower than in wild type mice (28.0±1.8 vs. 31.4±1.9; p<0.001). Cerebral blood flow, infarct size, and neurological scores were comparable in all groups. However, all nitric oxide knockout mice had markedly increased mortality compared with wild type mice (46% vs. 23%).ConclusioneNOS−/− or eNOS+/− mice may be used as a model of the cerebrovascular complications associated with abnormalities in nitric oxide signaling as seen in African Americans.Research support: NIH‐R21 award and GHSU start‐up to I.Y.S.

Endothelial nitric oxide synthase genotypes and haplotypes modify the responses to sildenafil in patients with erectile dysfunction

Erectile dysfunction (ED) is usually treated with sildenafil. Although genetic polymorphisms in the endothelial nitric oxide synthase (eNOS) gene may impair endogenous NO formation, there is little information about how eNOS polymorphisms and haplotypes affect the responses to sildenafil. We studied 118 patients; 63 patients had ED secondary to radical prostatectomy (PED) and 55 had organic, clinical ED. eNOS genotypes for three eNOS polymorphisms (T(-786)C, rs2070744; a variable number of tandem repeats (VNTR) in intron 4; and Glu298Asp, rs1799983) were determined, and eNOS haplotypes were estimated using PHASE 2.1. The clinical responses to sildenafil were evaluated and the patients were classified as good responders (GR) or poor responders (PR) when their changes in five-item version of International Index for Erectile Function questionnaire were above or below the median value. The TC/CC genotypes and the C allele for the T(-786)C polymorphism were more common in GR, compared with PR patients with PED. However, the 4b4a/4a4a genotypes and the 4a allele for the VNTR polymorphism in intron 4 were more common in GR, compared with PR patients with clinical ED. The C-4a-Glu haplotype was more common in GR than in PR patients with PED. Conversely, the T-4b-Asp haplotype was less common in GR than in PR patients with PED. No other significant differences were found. Our findings show evidence that eNOS polymorphisms affect the responses of PED and clinical ED patients to sildenafil.

Endothelial Nitric Oxide Synthase genotypes in the etiology of retinopathy of prematurity in premature infants

Purpose: Retinopathy of Prematurity (ROP) is a vasoproliferative disorder affecting preterm infants leading to visual impairment. ROP is more common in Caucasians than African Americans. Very low birth weight infants have immature retinas and are susceptible to ROP. Because of differences in individual responses to the treatment, various genetic factors have been looked into to understand the etiology of ROP. Endothelial nitric oxide (eNO) serves as a vasodilator, relaxes smooth muscle, prevents platelet aggregation, and facilitates improved blood flow and vascular tonicity. Mutant eNO synthase (eNOS) genotypes result in reduced nitric oxide levels by decreasing enzyme activity. Since eNO affects vasculature and ROP is a vascular disease, the present investigation was aimed at studying the association of genotypes with ROP.Methods: Two eNOS gene single nucleotide polymorphisms (SNPs) (T-786C, and G894T) were studied by microplate-Restriction Fragment Length Polymorphism Polymerase Chain Reaction (RFLP PCR) method. Genotypes were studied in 146 premature infants.Results: The present data showed significant differences in the baseline gene frequencies between Caucasians and African Americans. ROP patients displayed 3-fold higher frequencies of mutant -786C and 894T alleles in both ethnicities compared to respective controls.Conclusions: The present data suggest ethnic stratification of genotypes. Mutant -786C and 894T alleles are significant risk factors in the development of ROP, and suggest a strong association between eNOS polymorphisms and the disease. It is interesting to know if a larger dataset of ROP patients can confirm our initial findings.

Low folate levels may be an atherogenic factor regardless of homocysteine levels in young healthy nonsmokers

Low folate and high homocysteine levels are emerging as important risk factors for atherosclerosis and predictors of early coronary heart disease. We evaluated folate and homocysteine levels, compared them with endothelial function, and analyzed their association with the methylenetetrahydrofolate reductase (MTHFR) and endothelial nitric oxide synthase genotypes. We recruited 71 young healthy male nonsmokers without overt cardiovascular or renal disease. Plasma homocysteine levels were enhanced 2-fold in the subjects with the MTHFR 677T/T compared with the others ( P = .0001) and also enhanced in the subjects with the endothelial nitric oxide synthase −786C allele ( P = .031). Homocysteine levels were independently predicted only by the MTHFR genotype. A relationship between folate and homocysteine levels was not significant. Plasma folate levels were associated independently either with high-density lipoprotein cholesterol levels or with endothelial function in the brachial artery. These results suggest that low folate levels may be a risk factor for cardiovascular diseases regardless of homocysteine levels and that the subjects with lower folate levels should be recommended for dietary folic acid supplementation to elevate endothelial function and probably increase high-density lipoprotein cholesterol levels.

The relation of adiponectin and tumor necrosis factor α levels between endothelial nitric oxide synthase, angiotensin-converting enzyme, transforming growth factor β, and tumor necrosis factor α gene polymorphism in adrenal incidentalomas

The aim of our study was to demonstrate demographic characteristics, presence of inflammatory markers, distribution of angiotensin-converting enzyme (ACE), tumor necrosis factor (TNF), endothelial nitric oxide synthase (eNOS) genotypes and relations among these parameters in these patients and control subjects. Study samples were collected from 50 patients with adrenal mass and 30 control groups. The eNOS, ACE, TNF-alpha, transforming growth factor (TGF)-beta genes polymorphisms, TNF-alpha, adiponectin levels were analysed in 50 unrelated Turkish patients with a diagnosis of adrenal incidentaloma (AI). There was statistically significant difference between TNF-alpha levels of patient and controls (p=0.048). We have not detected the connection between TGF-beta, TNF-alpha, ACE, eNOS gene polymorphism with serum TNF-alpha and adiponectin levels. In this study, we demonstrated that there were significant differences for ACE genotypes in the patients when compared to the controls (p<0.05). The percentages of the ID, DD, II genotypes for ACE gene polymorphism in the patients group were 30.0, 13.0, 7.0%, respectively. According to different cases of eNOS, TGF-beta, ACE, and TNF-alpha gene genotypes; no statistical significant difference was found between basal cortisol, ACTH, DHEAS, metanephrine, renin, aldosterone, normetanephrine, 17-hydroxyprogesterone, 1 mg low-dose dexamethasone suppression test-cortisol response and AI size. In this study, I/D genotype was determined to be statistically higher in ACE gene in patients with AI (p=0.014).

Correlates Of Endothelial Function And The Peak Systolic Blood Pressure Response To A Graded Maximal Exercise Test

PURPOSE: An elevated systolic blood pressure (SBP) response during maximal exercise may be a predictor of endothelial dysfunction and future hypertension. We examined associations among the peak SBP response to a graded exercise stress test (GEST) and correlates of endothelial function among men (n=48, 43.7±1.4yr) with high BP (145.6±1.5/85.9±1.1mmHg). METHODS: For 20 min prior to the GEST, BP was measured every 2 min in the seated position via auscultation and averaged as baseline BP. Volunteers completed a maximal cardiopulmonary GEST to determine peak oxygen consumption (VO2peak). Brachial artery reactivity (BAR) was measured 3 and 5 min post-occlusion and expressed as a % change from baseline. Nitric Oxide (NO) was measured via chemiluminescence assay. Plasma glucose concentrations were determined in duplicate by an automated glucose oxidase method. Endothelial nitric oxide synthase genotype (ENOS -786 T>C; rs2070744) (ENOS TT, n=24; ENOS TC/CC, n=24) was determined by polymerase chain reaction and restriction enzyme digestion. Simple linear and multiple variable regression analyses examined relationships among the change in peak SBP achieved on the GEST and correlates of endothelial function. RESULTS: Linear regression analyses revealed the peak SBP change was positively correlated to blood glucose (r2=0.063, p=0.015), age (r2=0.016, p=0.024), VO2peak(r2=0.014, p=0.037), ENOS -786 T>C (r2=0.051, p=0.026), baseline SBP (r2=0.005, p=0.084), and baseline NO (r2=0.013, p=0.053); and negatively correlated to % BAR change at 3 min post-occlusion (r2=0.104, p=0.029). Multiple variable regression analyses indicated that this model explained 26.7% of the peak SBP response to a GEST. Lastly, among carriers of the ENOS C786 risk allele, the peak SBP change was 11.1±5.0mmHg higher ENOS TT homozygotes, 92.4 versus 81.3mmHg, respectively (p=0.03). CONCLUSIONS: Surrogate measures of endothelial function appear to explain a clinically significant portion of the peak SBP response to a GEST. Further work is needed to investigate how interactions among clinical and genetic correlates of endothelial function explain the variability in the peak SBP response to a GEST. Supported by an American Heart Association Grant in Aid #0150507N.

Polymorphisms in Genes Related to Oxidative Stress (CAT, MnSOD, MPO, andeNOS) and Acute Toxicities from Radiation Therapy following Lumpectomy for Breast Cancer

Because radiotherapy exerts cytotoxic effects via generation of massive oxidative stress, we hypothesized that catalase, manganese superoxide dismutase, myeloperoxidase (MPO), and endothelial nitric oxide synthase (eNOS) genotypes might result in greater risk of radiotoxicity. Cases (n = 446) were Caucasian women with breast cancer who received radiotherapy following lumpectomy. Genotypes were determined by matrix-assisted laser desorption/ionization time-of-flight. The development of acute reactions (moist desquamation) associated with genotypes was modeled using the Cox proportional hazards model, accounting for cumulative biologically effective radiation dose. Genotypes associated with higher levels of reactive oxygen species (ROS) were not associated with risk of radiotoxicity. However, relationships between overweight/obesity [body mass index (BMI), >25] and radiotoxicity risk seemed to be modified by eNOS and MPO genotypes associated with higher generation of nitric oxide and ROS, respectively. Women with high BMI (>25) and eNOS GG genotypes were at more than a 6-fold increase in risk (hazard ratio, 6.39; 95% confidence interval, 2.53-16.15) compared with those with BMI <25, and for MPO, those with high BMI (>25) and GG genotypes also had greater risk of radiotoxicity (hazard ratio, 3.61; 95% confidence interval, 1.78-7.35) compared with those with BMI <25. Overweight/obesity was not a strong risk factor among women with other eNOS and MPO genotypes. Exploratory analysis using classification and regression trees indicated that total number of risk alleles contributed, in part, to acute toxicity outcomes among a subgroup of women. Associations between BMI and radiotoxicity risk may be most apparent among women with genotypes related to higher levels of oxidative stress. Regression trees may be useful in future studies to examine the contributions of multiple factors to individual susceptibility to adverse effects of cancer treatment.

The T−786C Endothelial Nitric Oxide Synthase Genotype Predicts Cardiovascular Mortality in High-Risk Patients

This study sought to investigate the impact of a common T(-786)C single-nucleotide polymorphism (SNP) in the promoter of the endothelial nitric oxide synthase (eNOS, NOS3) gene on cardiovascular (CV) death in a prospective cohort study. The T(-786)C SNP eNOS gene implies a blunted endothelium-dependent vasodilation in hypertensive patients and was associated with multivessel coronary artery disease in cross-sectional studies, but it remained unsettled whether it carried prognostic information. In consecutive white patients of the GENICA (Genetic and Environmental Factors in Coronary Atherosclerosis) study, who underwent coronary angiography between 1999 and 2001, we determined the incidence of CV death at follow-up. The eNOS T(-786)C and the exon 7 G(894)T SNPs were determined by melting curve analysis of amplicons from allele-specific fluorescence resonance energy transfer probes. Plasma levels of nitrate/nitrite, nitrotyrosine, and myeloperoxidase were also measured. The Kaplan-Meier and Cox regression analyses were used to assess the impact of SNPs on event-free survival. Complete follow-up data were obtained in 1,086 (98%) patients. After a median follow-up of 1,296 days (range 4 to 2,057 days), we observed 85 (8.2%) CV deaths. There was a significant impact of the T(-786)C eNOS genotype on CV death-free (p = 0.0102) survival, but no differences in CV death rates across G(894)T genotypes. The TT individuals, who showed a lower survival, exhibited higher plasma myeloperoxidase (p < 0.0001) and lower levels of nitrotyrosine (p < 0.0001) than CC patients. The T(-786)C SNP in the promoter of eNOS bears independent prognostic information and is associated with changes in markers of oxidant stress in high-risk white patients referred for coronary angiography.

Endothelial nitric oxide synthase genotype and haplotype are not associated with diabetic retinopathy in diabetes type 2 patients

Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene have been associated with the development of diabetic retinopathy (DR) in patients with type 1 diabetes mellitus (T1DM), but not with T2DM. However, no previous study has analyzed combinations of genetic markers (haplotypes), which can be more informative. We studied three eNOS genetic polymorphisms: a single nucleotide polymorphism in the promoter region (T −786C), in exon 7 (Glu298Asp), and a variable number of tandem repeats in intron 4 (b/a) in 103 healthy controls, and in 170 patients with T2DM (without DR, N = 114; with DR, N = 56). We also examined the association of eNOS gene haplotypes with T2DM and with DR. No differences were found in the frequencies of genotypes and alleles of the three polymorphisms among the three groups of subjects. However, the “C-Glu-b” haplotype was more common in healthy controls (24%) than in T2DM patients (7%) ( P = 0.0001). Finally, no significant difference in the distribution of eNOS haplotypes frequencies was found when T2DM patients with or without DR were compared ( P = 0.7372). These findings suggest no association between DR and individual eNOS haplotypes in T2DM patients. The “C-Glu-b” haplotype, however, may have a protective effect against T2DM. Further studies should be conducted to address the molecular basis for such an effect.

Association of endothelial nitric oxide synthase genotypes with bone mineral density, bone loss, hip structure, and risk of fracture in older women: The SOF study

Nitric oxide (NO) is an important bone-signaling molecule. We examined the associations between the Glu298Asp polymorphism of NOS3, indices of bone strength, and the incidence of fracture among 6691 women aged 65 years and older enrolled in the Study of Osteoporotic Fractures. Calcaneal BMD was measured at an initial exam and after an average of 5.9 years of follow-up. Hip BMD was measured at an initial exam and after 3.7 years of follow-up. Baseline spine BMD and hip structural parameters were measured. Incident hip fractures were confirmed by review of radiographic reports; follow-up was greater than 98% complete. Incident vertebral fractures were defined by morphometry using lateral spine radiography at baseline and an average of 3.7 years later. The frequencies of the NOS3 Glu298Asp genotypes were Glu/Glu = 46.2%, Glu/Asp = 42.7%, and Asp/Asp = 11.1%. There were no significant associations between NOS3 genotypes and initial calcaneal BMD, hip BMD, or rate of change in hip or calcaneal BMD. None of the hip structural parameters differed substantially by genotype. NOS3 genotype was not significantly associated with either incident or prevalent radiographic vertebral fractures. Women with the heterozygous Glu/Asp genotype had a borderline statistically significantly lower rate of hip fracture than either the Glu/Glu genotype (HR = 0.87, 95% CI: 0.74, 1.01) or the Asp/Asp genotype (HR = 0.78, 95% CI: 0.62, 0.98). In conclusion, the Glu298Asp polymorphism does not contribute substantially or consistently to indices of bone strength in this sample of older white women, although our findings suggest allelic variation at the NOS3 locus maybe associated with hip fracture risk. Confirmation of these findings is needed in other populations and with additional markers within and flanking the NOS3 gene region.

Possible interactions of the endothelial constitutive nitric oxide synthase genotype with alcohol drinking and walking time for high serum uric acid levels among Japanese

A variable number of tandem repeat polymorphism located in intron 4 of the gene for endothelial constitutive nitric oxide synthase ( ecNOS) is reported to be significantly associated with the nitric oxide level, which influences serum uric acid (SUA). To cast light on any association between the polymorphism and hyperuricemia, as well as gene-environment interactions, a cross-sectional study was conducted for 703 health checkup examinees (213 men and 490 women). The age-adjusted odds ratio (aOR) of hyperuricemia (≥7 mg/dL) for ecNOS 4/ 4, 4/ 5, or 5/ 6 genotypes ( non- 5/ 5 group) as compared with the 5/ 5 genotype was 2.41 (95% confidence interval [CI], 1.09-5.30) in men. The aORs for drinking alcohol relative to never drinking were found to be 8.93 (95% CI, 1.02-78.16) among men with non- 5/ 5 genotypes and 1.76 (95% CI, 0.59-5.26) for their 5/ 5 counterparts. Moreover, the aORs for heavy drinking (≥50 mL/d) were 23.16 (95% CI, 2.14-250.35) and 2.48 (95% CI, 0.75-8.15), respectively. The interaction between the genotype and current drinking was 3.10 (95% CI, 0.45-21.41). The aORs for more than 30 minutes of daily walking relative to 30 minutes or less of daily walking were found to be 1.54 (95% CI, 0.40-5.95) among men with non- 5/ 5 genotypes and 0.31 (95% CI, 0.12-0.81) for their 5/ 5 counterparts. The interaction between the genotype and more than 30 minutes of daily walking was 4.92 (95% CI, 0.95-25.64). This study indicated that the ecNOS variable number of tandem repeat polymorphism influences the SUA level in men. Although the interactions were not significant, alcohol intake may be more influential among men with non- 5/ 5 genotypes and walking may be more effective among men with the 5/ 5 genotype. These findings would be informative for men with high SUA levels.

Endothelial Nitric Oxide Synthase (NOS3) Genotype in Pulmonary Artery Hypertension

Endothelial Nitric Oxide Synthase (NOS3) Genotype in Pulmonary Artery Hypertension

Association of ENOS polymorphism with basal peritoneal membrane function in uremic patients

Background:Basal peritoneal permeability has a major impact on the outcome of peritoneal dialysis (PD) patients, but the determinant of this is unknown. Early evidence suggests that peritoneal permeability is affected by nitric oxide (NO) activity. Recently, a gene polymorphism of the endothelial NO synthase (ENOS) gene was identified that is associated with circulating nitrate levels. Methods:We performed a cross-sectional study to examine the relationship between ENOS4(a/b) gene polymorphism and basal peritoneal function in 86 Chinese incident PD patients. ENOS genotypes for variable number tandem repeats in intron 4 (a/b) were identified by polymerase chain reaction. Patients were classified into 2 groups according to results of a basal peritoneal equilibration test (PET) performed within 2 months of dialysis therapy: group A consisted of patients with low (L)/L average (LA) PET results, and group B consisted of those with H and HA PET results. Results:Group A (L/LA) had a significantly greater prevalence of ENOS aa/ab genotype than group B (H/HA; 30% versus 12%; P < 0.05). Frequencies of the ENOS a allele also were greater in group A (L/LA) than group B (H/HA) (16% versus 6%; P = 0.03). ENOS genotype remained an independent predictor for peritoneal transport after adjustment for sex, body weight, and prevalence of diabetes by multivariate analysis (adjusted odds ratio, 3.3; confidence interval, 1.1 to 3.7; P = 0.03). Subjects with the aa/ab genotype had significantly lower mass transfer area coefficients (7.35 ± 3.4 versus 9.48 ± 5.21 mL/min; P = 0.023) and dialysate-plasma creatinine ratios at 4 hours (0.55 ± 0.13 versus 0.62 ± 0.14; P = 0.048) than those with the bb genotype. Conclusion:ENOS4(a/b) gene polymorphism is associated with basal peritoneal permeability in uremic Chinese patients.

The T-786C endothelial nitric oxide synthase genotype is a novel risk factor for coronary artery disease in Caucasian patients of the GENICA study

ObjectivesWe investigated the association of polymorphisms in the promoter region and exon 7 endothelial nitric oxide synthase (eNOS) gene with coronary artery disease (CAD). BackgroundEndothelial dysfunction foretells cardiovascular events and can be genetically determined. MethodsWe genotyped for the promoter (T-786C) and exon 7 (Glu298Asp, G894T) polymorphisms in 1,225 subjects; 1,106 were consecutive patients undergoing coronary angiography and 119 control subjects without any cardiovascular risk factors. Genotyping was performed with melting curve analysis of polymerase chain reaction products from allele-specific acceptor and donor probes that were 5′- and 3′-end labeled with LCRed640 and fluorescein, respectively; CAD was assessed by quantitative coronary angiography. We performed multiple logistic regression analysis for the effect of the T-786C, the missense Glu298Asp variant, and other coronary risk factors on two- and three-vessel CAD. ResultsThe overall genotype distribution of T-786C (CC = 17.7%, CT = 40.4%, and TT = 41.9%) and Glu298Asp (GG = 43.3%, GT = 37.0%, and TT = 19.7%) was consistent with the Hardy-Weinberg equilibrium. The regression analysis showed that the T-786C, but not the missense Glu298Asp variant, significantly predicted CAD, independent of other risk factors. Compared with TT homozygous, subjects carrying the C allele had a significant (p = 0.002) increase in the odds ratio of harboring two- or three-vessel CAD of 1.672 (95% confidence interval, 1.062 to 2.527). A subgroup analysis confirmed this effect of the T-786C polymorphism in men (p = 0.007), cigarette smokers (p = 0.001), subjects older than 60 years of age (p = 0.007), with hypercholesterolemia (p = 0.011), low high-density lipoprotein cholesterol (p = 0.006), and overweight or with obesity (p = 0.041). ConclusionsThe C allele at the T-786C endothelial nitric oxide synthase polymorphism is associated with a higher risk of multivessel CAD in Caucasians.

Endothelial nitric oxide synthase variants in cystic fibrosis lung disease.

Variants in the genes encoding for the nitric oxide synthases may act as disease modifier loci in cystic fibrosis, affecting both an individual's nitric oxide level and pulmonary function. In this study, the 894G/T variant in exon 7 of the endothelial nitric oxide synthase gene was related to exhaled nitric oxide and pulmonary function in 70 cystic fibrosis patients who were aged 14.8 +/- 6.9 years (mean +/- SD), with a FEV1 of 69.4 +/- 24.8% predicted. Although there was no association between endothelial nitric oxide synthase genotypes and exhaled nitric oxide in males, nitric oxide levels were significantly higher in female cystic fibrosis patients with an 894T mutant allele, compared with female patients homozygous for the 894G wild-type allele (7.0 +/- 4.4 versus 3.6 +/- 1.9 parts per billion, p = 0.02). Furthermore, in female patients, colonization of airways with Pseudomonas aeruginosa was significantly (p < 0.05) less frequent when carrying an 894T mutant allele as compared with wild type. These data suggest that the 894T variant in the endothelial nitric oxide synthase gene is associated with increased airway nitric oxide formation in female cystic fibrosis patients, possibly affecting colonization of airways with P. aeruginosa.

Methylenetetrahydrofolate Reductase Gene Polymorphism, Hyperhomocysteinemia, and Cardiovascular Diseases in Chronic Hemodialysis Patients

Cardiovascular disease (CVD) is the principle cause of death in patients with end-stage renal disease. Some gene polymorphisms and hyperhomocysteinemia have been implicated in the pathogenesis of CVD. The aim of this study was to assess the relationships between angiotensin-converting enzyme genotype, endothelial nitric oxide synthase genotype, and methylenetetrahydrofolate reductase (MTHFR) genotype and CVD in patients on hemodialysis and to clarify the determinants of plasma homocysteine level. One hundred and sixty-eight patients on hemodialysis (87 males and 81 females, mean age 60.7 ± 13.1 years) were included. A history of CVD was present in 25% of the patients. There was a significant difference in the distributions of MTHFR non-VV genotype and MTHFR VV genotype between patients with a CVD history and patients without a CVD history, but no difference in the distributions of angiotensin-converting enzyme genotypes and endothelial nitric oxide synthase genotypes. The plasma homocysteine concentration was significantly higher in patients with MTHFR VV genotype than in patients with MTHFR non-VV genotype. The plasma homocysteine concentration was negatively correlated with plasma vitamin B₁₂ concentration and plasma folate concentration. On stepwise multiple-regression analysis for the predictors of plasma homocysteine concentration, MTHFR VV genotype and gender were significant. In conclusion, MTHFR polymorphism may be a risk factor for CVD in patients on hemodialysis, and MTHFR VV genotype and gender may be strong determinants of the plasma homocysteine level.

Relations between ACE gene and ecNOS gene polymorphisms and resistive index in type 2 diabetic patients with nephropathy.

ACE and endothelial cell nitric oxide synthase (ecNOS) genotypes have been reported to be related to the incidence of renal diseases and coronary artery diseases. In order to assess the effect of the gene polymorphism of both ACE and ecNOS on renal hemodynamic abnormality, we examined 155 Japanese patients with type 2 diabetes with various stages of nephropathy. The patients ranged in age from 40 to 72 years (92 men and 63 women). They were divided into four groups: group 1 consisted of patients with urinary albumin excretion (UAE) <30 mg/day (n = 69), group 2 had 30 < or = UAE < 300 mg/day (n = 44), group 3 had UAE > or =300 mg/day and serum creatinine <1.5 mg/dl (n = 22), and group 4 had serum creatinine >1.5 mg/dl (n = 20). Intrarenal hemodynamics were studied by duplex Doppler sonography in patients with type 2 diabetes. The ACE and ecNOS gene polymorphisms were examined by polymerase chain reaction. There were no significant differences in sex, BMI, and blood glucose level, but there were differences in HbA(1c) and lipoprotein profiles among the four groups. There were no significant differences in the distribution of ACE genotype or in the frequency of the ecNOS 4a allele among the four groups. Resistive index (RI) values of the interlobar arteries of group 4 were significantly higher than those of groups 1, 2, and 3, whereas the RI values were not significantly different among groups 1, 2, and 3. Multiple regression analysis showed that age, duration of diabetes, systolic and diastolic blood pressure, and creatinine clearance were significantly associated with the increased RI values, but that there was no significant association between RI values and the ecNOS genotype (R(2) = 0.613, P < 0.0001). These results suggest that intrarenal hemodynamic abnormalities are present as a feature of the progression of nephropathy in type 2 diabetes, and that they are associated with age, duration of diabetes, decreased creatinine clearance, and blood pressure, but not with the genetic factors of the ACE and ecNOS gene polymorphism in nephropathy of type 2 diabetes.