The relationship between endothelial nitric oxide synthase gene polymorphism (T-786 C) and coronary artery disease in the Turkish population

Previous studies revealed that there were various mutations on endothelial nitric oxide synthase (eNOS) gene and these mutations might be a risk factor for coronary artery disease (CAD), myocardial infarction (MI), and hypertension (HT). In this study, we aimed to investigate the relationship between eNOS gene polymorphism (T-786 C) and coronary artery disease in the Turkish population. Two hundred and eleven unrelated individuals (152 male, 59 female, mean age 59 years, range 27–85) whose angiographic examinations were performed in our hospital were enrolled into the study; 159 of these had angiographically determined coronary artery lesions (≥50% stenosis at least in one vessel). Fifty-two individuals were free of coronary artery disease on their coronary angiography. The Gensini scoring system was used to determine the severity of the CAD. The polymerase chain reaction (PCR) method was used for genotyping the individuals. To determine the independent risk factors for coronary artery disease, multivariate logistic regression analysis was used. The variant distribution of the T-786 C polymorphism was as follows. For all individuals: TT 94 (44.5%), TC 88 (41.7%), CC 29 (13.8%); in CAD patients: TT 63 (39.6%), TC 73 (45.9%), CC 23 (14.5%); and in normal individuals: TT 31 (59.6%), TC 15 (28.8%), CC 6 (11.5%). There was a statistically significant difference in the variant distribution between CAD and normal individuals (P < 0.05). On the other hand, when we compared the frequency of the at-least-one-C-allele carriers (CC+TC, dominant model) and TT homozygous, those with at least one C allele were more prevalent in CAD patients. The results were as follows. In coronary artery disease patients: CC+TC 96 (60.4%), TT 63 (39.6%); in normals: TC+CC 21 (40.4%), TT 31 (59.6%) (P < 0.01). When we compared the allele distribution (T vs C, additive model) between CAD patients and normal controls, the results were as follows: T 0.625 vs 0.740, C 0.375 vs 0.260; there was also a statistically significant association between CAD and C allele (P < 0.05). When we compared the means of the Gensini scores between each genotype of the T-786 C mutation, there was a statistically significant difference. The results were TT (48.6 ± 37.3, median 43.0), TC (55.4 ± 41.2, median 41.0), CC (77 ± 43.6, median 80.0) (P < 0.05). Multivariate logistic regression analysis revealed that C-dominant (CC+TC) individuals had 2.9-fold more likelihood to suffer from CAD (odds ratio: 2.902; confidence interval: 1.272–6.622) (P < 0.05). We conclude that the T-786 C polymorphism of eNOS gene might be a risk factor for coronary artery disease in the Turkish population.     

eNOS基因5'侧翼区T-786C多态性与冠心病的相关性研究

目的探讨内皮型一氧化氮合酶（eNOS）基因5’侧翼区T-786C多态性与中国汉族人冠心病和冠状动脉狭窄支数的关系。方法依据eNOS基因5’侧翼区T-786C位点设计引物，应用多聚合酶链反应-限制性片段长度多态性（PCR-RFLP）分析方法检测136例经冠状动脉造影证实的冠心病（冠心病组）和77例非冠心病（对照组）患者的eNOS基因T-786C多态性。结果（1）冠心病组TT＋TC和CC基因型频率分别为72．8％、25．7％、1．5％，对照组分别为92．2％、6．7％、0（χ^2=11．5，P〈0．01）；（2）冠心病组C等位基因的频率高于对照组C等位基因的频率（14．3％比3．9％，χ^2=11．5，P〈0．01）；（3）多元logistic回归显示eNOS T-786C基因多态性是冠心病的独立危险因素（OR值5．261，95％CI：2．010～13．768）；（4）在1、2、3支冠脉血管狭窄组中。TC＋CC基因型频率分布分别为21．4％、25．0％和33．3％（χ^2=1．83，P〉0．05），C等位基因频率分别为10．7％、12．5％、18．5％（χ^2=2．66，P〉0．05）。结论（1）eNOS T-786C基因多态性是冠心病的遗传危险因素，并独立于冠心病其它的经典危险因素；（2）eNOS T-786C基因多态性与冠脉狭窄的支数元关。     

内皮型一氧化氮合酶基因多态性与急性心肌梗死的相关性探讨

目的　探讨内皮型一氧化氮合酶 (eNOS)基因多态性与急性心肌梗死 (AMI)的相关性。方法　依据eNOS基因外显子 7G894T位点设计引物 ,通过巢式聚合酶链反应 (PCR)扩增目的片段 ,限制性内切酶消化目的片段 ,琼脂糖凝胶电泳 ,紫外透射分析仪检测 ,计数 10 7例AMI病人及 81例健康者基因型及突变基因频率 ,通过χ2 检验有无统计学意义。结果　eNOS基因外显子 7的 894位点有 3种基因型 :GG、GT、TT。AMI组 10 7例中2 5例发生G894T突变 ,纯合子TT 9例 ,杂合子GT 16例。对照组 81例中 13例发生G894T突变 ,均为杂合子。两组等位基因纯合子突变具有非常显著统计学意义 ,x2 =5 4 2 9,P <0 0 5 ,两组等位基因总突变率 (纯合子 +杂合子 )无明显统计学意义 ,x2 =1 5 2 9,P >0 0 5。结论　eNOS基因 894位点TT型突变与AMI发病密切相关 ,是AMI发病的危险因子     

内皮型一氧化氮合酶基因多态性与冠心病的关系

内皮型一氧化氮合酶(eNOS)基因被列为冠心病(CHD)的一个候选易感基因。本文对与冠心病关系较为密切的三种eNOS基因多态性:4b/a、T786C和G894T的研究进展作一综述,对进一步认识冠心病的发病机制具有重要意义。     

内皮型一氧化氮合酶基因多态性与冠心病的研究进展

冠状动脉粥样硬化性心脏病（cronary atherosclerotic heart disease,CHD）简称冠心病,是指冠状动脉发生粥样硬化引起管腔狭窄或闭塞,导致心肌缺血缺氧或坏死引起的心脏病.吸烟、肥胖、高血压及代谢综合征等均已成为广为人知的几个冠心病重要危险因素.但也有患者没有这些危险因素存在,并且在一些个体中,常有明显的冠心病家族史,说明冠心病是环境与遗传危险因素动态相互作用所致的.目前已有诸多冠心病基因多态性研究,包括内皮型一氧化氮合酶（endothelial nitric oxide synthase,eNOS）.在近年的荟萃分析中显示,某些遗传变异可能为特定群体冠心病发病的危险因素之一.     

Endothelial nitric oxide synthase dysfunction in diabetic mice: importance of tetrahydrobiopterin in eNOS dimerisation

Aims/hypothesis Impaired nitric oxide (NO) bioactivity and increased superoxide (SO) production are characteristics of vascular endothelial dysfunction in diabetes. The underlying mechanisms remain unknown. In this regard, we investigated the role of tetrahydrobiopterin (BH4) bioavailability in regulating endothelial nitric oxide synthase (eNOS) activity, dimerisation and SO production in streptozotocin-induced diabetic mice.Methods Mouse aortas were used for assays of the following: (1) aortic function by isometric tension; (2) NO by electronic paramagnetic resonance; (3) SO by lucigenin-enhanced chemiluminescence and dihydroethidine fluorescence; (4) total biopterin and BH4 by high-performance liquid chromatography; and (5) eNOS protein expression and dimerisation by immunoblotting.Results In diabetic mouse aortas, relaxations to acetylcholine and NO levels were significantly decreased, but SO production was increased, in association with reductions in total biopterins and BH4. Although total eNOS levels were increased in diabetes, the protein mainly existed in monomeric form. Conversely, specifically augmented BH4 in diabetic endothelium preserved eNOS dimerisation, but the expression remained unchanged.Conclusions/interpretation Our results demonstrate that BH4 plays an important role in regulating eNOS activity and its functional protein structure, suggesting that increasing endothelial BH4 and/or protecting it from oxidation may be a rational therapeutic strategy to restore eNOS function in diabetes.     

内皮细胞型NO合酶基因第7外显子894G→T点突变与糖尿病肾病相关性研究

目的 探讨内皮细胞型NO合酶（eNOS)基因第7外显子894G→T点突变与中国北方汉族人2型糖尿病（T2DM）合并肾病（DN）之间的关系。方法 运用聚合酶链式反应限制性片段长度多态性技术（PCR－RFLP），结合DNA测序技术，检测了228例中国北方汉族人的eNOS基因第7外显子894G→T错义突变位点的基因型，其中T2DM患者143例（DN79例），健康成人85例，并对各组间的等位基因频率与基因型频率进行了比较。结果 ①T2DM组的T等位基因及TG基因型频率与正常对照（N）组无显著性差异（P＞0．05）。②DN＋组T等位基因及TG基因型频率显著高于糖尿病非肾病患者（P＜0．05）。③SBP、HbA1c、TC、TG和eNOS基因第7外显子894G→T点突变均与糖尿病肾病有关（P＜0．05）。结论 eNOS基因第7外显子894G→T点突变的T等位基因可能是中国人2型糖尿病易患肾病的独立危险因素。     

A T-786C polymorphism in 5'-flanking region of the endothelial nitric oxide synthase gene and endothelium-dependent arterial dilation in Type 2 diabetes.

OBJECTIVE: Several studies have shown that the T-786C polymorphism in 5'-flanking region of the endothelial nitric oxide synthase (eNOS) gene is associated with coronary artery disease in non-diabetic population. In the present study, we attempted to assess whether the T-786C polymorphism of eNOS gene is associated with endothelial dysfunction Type 2 diabetes. RESEARCH DESIGN AND METHODS: A total of 162 Type 2 diabetic men were studied. PCR/allele-specific probes were used to analyse the T-786C polymorphism of eNOS gene, and high resolution ultrasound was used to measure brachial artery diameter at rest, after reactive hyperaemia and after sublingual glyceryltrinitrate. RESULTS: The flow-mediated arterial dilation among subjects with T/C or C/C was 3.73+/-0.50%, which was significantly lower than that in subjects with T/T (4.15+/-0.49%) (P=0.000). On multiple linear regression analysis, the presence of C allele, mean blood pressure, low-density lipoprotein (LDL) and serum lipoprotein (a) [Lp(a)] were independent determinants for reduced endothelium-dependent arterial dilation (R2=0.175, P=0.0021). The flow-mediated arterial dilation in smokers with T/C or C/C was significantly lower than that in smokers with T/T (P<0.001), but not in non-smokers. In addition, the presence of C allele, LDL and Lp(a) were independent determinants for reduced endothelium-dependent arterial dilation (R2=0.258, P=0.0017) in smokers, but not in non-smokers. CONCLUSION: The C allele of T-786C polymorphism of eNOS gene is a genetic risk factor for endothelial dysfunction in Type 2 diabetic patients, especially among smokers.     

Nitric oxide production in rheumatoid arthritis

Abstract

Nitric oxide (NO), originally found as endothelium-derived relaxing factor (EDRF), is a free radical synthesized by NO synthases (NOS). Two isoforms exist in NOS, i.e. constitutive NOS (cNOS) and inducible NOS (iNOS). Inflammatory cytokines such as interleukin-1, interferon-γ, tumor necrosis factor-α induce iNOS expression in various cells including macrophages. Enhanced NO production is observed in arthritic conditions both in rodent models and human. The onset of arthritis in rodent models is significantly inhibited by the NOS inhibitor, N ^G-monomethyl-l-arginine. These data suggest a possible involvement of NO in the induction and/or maintenance of rheumatoid arthritis.     

Endothelial nitric oxide synthase gene (T-786C) polymorphism in patients with slow coronary flow

OBJECTIVES: In this study, we aimed to investigate the relationship between T-786C polymorphism of the endothelial nitric oxide synthase (eNOS) gene and slow coronary flow (SCF). STUDY DESIGN: A total of 56 patients with SCF but otherwise normal coronary arteries (mean age 48+/-9 years) and 37 controls with normal coronary angiograms (mean age 50+/-12 years) were enrolled in the study. Screening for the eNOS T-786C polymorphism was performed by restriction fragment length polymorphism methodology. RESULTS: In normal coronary artery and SCF groups, TT genotype frequency was 23 (62.2%) versus 22 (39.3%), TC heterozygote genotype frequency was 11 (29.7%) versus 30 (53.6%), and CC homozygote genotype frequency was 3 (8.1%) versus 4 (7.1%), respectively (P=0.07). In dominant model statistical analysis, total CC and CT genotype frequency in control and study groups was found to be 14 (37.3%) versus 34 (60.7%), respectively (P=0.025). A positive correlation was found between the mean thrombolysis in myocardial infarction frame count and C allele in patients with SCF (r=0.21, P=0.043). CONCLUSION: We concluded that the T-786C polymorphism of eNOS gene might be a risk factor for the SCF.     

The effect of circulating nitric oxide level on axial bone mineral density in postmenopausal Turkish women with rheumatoid arthritis: a preliminary report

The aim is to investigate the differences in the circulating nitric oxide (NO) levels of rheumatoid arthritis (RA) patients, healthy controls and osteoporotic (OP) patients. We also examined whether the circulating NO levels may be correlated with bone mineral density (BMD) in RA patients. Forty-five patients with RA, 30 healthy women and 30 osteoporotic patients were recruited from the outpatient clinic. All the subjects were female and postmenopausal. Serum NO levels were measured (Nitrite/Nitrate, calorimetric method 1746081, Roche diagnostics, Mannheim, Germany) and BMD was measured at the spine and hip using dual energy X-Ray absorbtiometry (DEXA, Norland XR-46). Height and weight were measured and body mass index was calculated. Circulating NO levels were significantly higher in RA patients than other groups. Moreover, the RA group showed significantly higher BMD at lumbar spine and femoral neck regions compared to osteoporotic patients. However, the RA group showed significantly lower BMD at all sites than the controls. There was no correlation between circulating NO levels and BMD in all groups. We suggest that, unlike postmenopausal osteoporosis, inflammation induced osteoporosis is associated with RA is characterised by relatively preserved bone mass at the axial bone regions, and circulating NO levels as a parameter or determinant of inflammation are not correlated with axial BMD in RA patients.     

Bleeding duodenal ulcer and association with polymorphism of endothelial constitutive nitric oxide synthase gene

Nitric oxide (NO) exerts both protective and proinflammatory actions in the gastrointestinal tract. Enhanced gastric NO synthase (NOS) activity has been shown in duodenal ulcer patients. Recently, intron-4 polymorphism of the endothelial constitutive (ec) NOS gene has been associated with some pathological conditions. Our aim was to determine the genotype and allele frequencies of the ecNOS4 polymorphism in peptic ulcer patients. The distribution of the polymorphism ecNOS4a/b was studied in 188 ulcer patients and 120 healthy controls, from genomic DNA. Genotypes ab, bb, and aa and allele frequency were similar in both peptic ulcer patients and controls, and no differences were found when patients and controls were analyzed according to the presence of several etiological factors. However, alelle a carrier status was associated with decreased risk of bleeding in duodenal ulcer patients (OR = 0.49; 95% CI = 0.25–0.95; P = 0.03). In conclusion, this ecNOS4 polymorphism gene could be related to susceptibility of duodenal ulcer patients to bleeding.     

内皮细胞型一氧化氮合酶基因多态性与糖尿病肾病的相关性研究

目的：探讨内皮细胞型一氧化氮合酶（eNOS)基因第7外显子894G→T点突变,及其第4内含子的1个27bp的插入／缺失（a/b)多态性,与2型糖尿病肾病（DN）之间的关系。方法：894G→T点突变采用聚合酶链反应限制性片段长度多态性（PCR－RFLP）技术,27bp的a/b多态性采用聚合酶链反应结合4％琼脂糖凝胶电泳分离技术。比较各组间的等位基因频率与基因型频率。结果：（1）早期糖尿病肾病组（DN^ 组）T等位基因及TG基因型频率显著高于糖尿病非肾病患者（DN^-组,P＜0．05）。（2）DN^ 组a等位基因及ab基因型频率显著高于DN^-组（P＜0．05）。（3）DN^ 组的TGab基因型频率亦显著高于DN^-组（P＜0．05）。（4）糖基化血红蛋白（GHbA1c),收缩压（SBP）,总胆固醇（TC）,eNOS基因第7外显子894G→T基因点突变及第4内含子a/b多态性均属糖尿病肾病的独立危险因素。结论：糖尿病患者eNOS基因第7外显子T等位基因及第4内含子a等位基因与DN^ 的发生密切相关,两种等位基因同时存在者,DN^ 发病风险更高。     

Subcellular distribution of nitric oxide synthase isoforms in the rat duodenum

AIM:To study the cell-type specific subcellular distribution of the three isoforms of nitric oxide synthase(NOS) in the rat duodenum.METHODS:Postembedding immunoelectronmicroscopy was performed,in which primary antibodies for neuronal NOS(nNOS),endothelial NOS(eNOS),and inducible NOS(iNOS),were visualized with protein A-gold-conjugated secondary antibodies.Stained ultrathin sections were examined and photographed with a Philips CM10 electron microscope equipped with a MEGAVIEW II camera.The specificity of t...     

Endothelial nitric oxide synthase G894T gene polymorphism and response to skin reactive hyperemia

Post occlusive skin reactive hyperemia (PORH) is a tool used to assess microcirculation. Endothelial nitric oxide synthase (eNOS) mediates nitric oxide (NO) production; polymorphism of the eNOS gene may affect response to the PORH process. This study aims to determine whether eNOS G894T gene polymorphism affects response to skin PORH. 230 normotensive male and females between 18 and 40 years participated in this cross-sectional study. 170 subjects were of the homozygous GG genotype, whereas 60 were of the GT genotype. Skin PORH was performed by occlusion of the upper arm at 200 mm Hg for 3 min. Skin perfusion and temperature were monitored before, during and after occlusion release using the laser Doppler fluximetry. There were no significant differences between genotypes in their baseline blood pressure, serum cholesterol, BMI and age. Maximum change in perfusion after occlusion release (PORHmax) for the GG and GT genotypes were not significantly different at 50.15 ± 1.29 vs. 47.92 ± 2.17 AU; ANCOVA, p = 0.351. Peak perfusion (PORHpeak) were also not significantly different between the two genotypes (61.23 ± 1.36 vs. 57.72 ± 2.32 AU; p = 0.169). Minimum baseline perfusion were however higher in the GG compared to the GT genotype (10.83 ± 0.29 vs. 9.61 ± 0.50, p = 0.029). We conclude that microvascular reactivity, assessed by change in perfusion after temporary ischemia was not significantly different between the GG and GT genotypes of the eNOS G894T gene. eNOS 894T allele carriers however, have lower baseline perfusion compared to the homozygous G894 allele carrier.     

基因芯片技术分析内皮型一氧化氮合酶基因多态性与冠心病的关系

目的探讨内皮型一氧化氮合酶（eNOS）Glu298Asp基冈多态性与冠心病的关系。方法以89例冠心病患者为病例组（男性62例,女性27例）,均行冠状动脉造影确诊,对照组78例（男性44例,女性34例）均行冠状动脉造影排除冠心病,运用基因芯片技术方法检测eNOS Glu298 Asp基因的多态性,对比分析冠心病组及对照组eNOS Glu298 Asp基因型及等位基因的差异。结果eNOS Glu298 Asp基因型分布冠心病组与对照组比较差异无统计学意义（P=0．495）,D等位基因频率冠心病组（10．11％）与对照组（10．27％）相比差异无统计学意义（P=0．965）。结论eNOS Glu298 Asp基因变异与冠心病的发病可能无相关性。     

New progress in understanding roles of nitric oxide during hepatic ischemia-reperfusion injury

Hepatic ischemia-reperfusion injury (HIRI) is a major clinical cause of morbidity and mortality in liver surgery and transplantation. Many studies have found that nitric oxide (NO) plays an important role in the HIRI and its increase or decrease can affect the progression and outcome of HIRI. However, the role of NO in HIRI is controversial and complicated. NO derived by endothelial NO synthase (eNOS) shows a protective role in HIRI, while excessive NO derived by inducible NO synthase (iNOS) accelerates inflammation and increases oxidative stress, further aggravating HIRI. Nevertheless, the overexpression of eNOS may exacerbate HIRI and iNOS-derived NO in some cases reduces HIRI. Here we review the new progress in the understanding of the roles of NO during HIRI: (1) NO possesses different roles in HIRI by increasing NO bioavailability, down-regulating leukotriene C4 synthase, inhibiting the activation of the nuclear factorκB (NFκB) pathway, enhancing cell autophagy, and reducing inflammatory cytokines and reactive oxygen species (ROS). And NO has both protective and deleterious effects by regulating apoptotic factors; (2) eNOS promotes NO production and suppresses its own overexpression, exerting a hepatoprotective effect reversely. Its activation is regulated by the PI3K/Akt and KLF2/AMPK pathways; and (3) iNOS derived NO mainly has deteriorating effects on HIRI, while it may have a protective function under some conditions. Their expression should reach a balance to reduce the adverse side and make NO protective in the treatment of HIRI. Thus, it can be inferred that NO modulating drugs may be a new direction in the treatment of HIRI or may be used as an adjunct to mitigate HIRI for the purpose of protecting the liver.     

一氧化氮及其合酶在哮喘发病机制中的作用

探讨一氧化氮及其合酶在哮喘发病机制中的作用。方法 采用哮喘豚鼠模型，将豚鼠分为４组；１．哮喘组，用１０％卵白蛋白腹腔注射１ｍｌ致敏，２周后用１％卵白蛋白超声雾化吸入致其哮喘发作．２；肾上腺皮质激素预防组；诱喘同哮喘组，在每次诱喘前腹腔滴注地塞米松０．５ｍｇ／ｋｇ。３．硝基精氨酸甲酯预防组；诱喘同哮喘组，每次诱喘产腹腔注射ＬＮＮＡ０．４ｍｇ／ｋｇ。４．正常对照组；用生理盐水代替诱喘剂。每组分别测定其     

Endothelial cell-specific overexpression of endothelial nitric oxide synthase in Ins2Akita mice exacerbates diabetic nephropathy

Previous studies demonstrated that global deficiency of eNOS in diabetic mice exacerbated renal lesions and that overexpression of eNOS may protect against tissue injury. Our study revealed for the first time overexpression of eNOS leads to disease progression rather than protection. Transgenic mice selectively expressing eNOS in endothelial cells (eNOSTg) were cross bred with Ins2Akita type-1 (AK) diabetic mice to generate eNOS overexpressing eNOSTg/AK mice. Wild type, eNOSTg, AK and eNOSTg/AK mice were assessed for kidney function and blood glucose levels. Remarkably, overexpressing eNOSTg mice showed evidence of unpredicted glomerular injury with segmental mesangiolysis and occasional microaneurysms. Notably, in eNOSTg/AK mice overexpression of eNOS led to increased glomerular/endothelial injury that was associated with increased superoxide levels and renal dysfunction. Results indicate for the first time that overexpressing eNOS in endothelial cells cannot ameliorate diabetic lesions, but paradoxically leads to progression of nephropathy likely due to eNOS uncoupling and superoxide upsurge. This novel finding has a significant impact on current therapeutic strategies to improve endothelial function and prevent progression of diabetic renal disease. Further, the eNOSTg/AK model developed in this study has significant translational potentials for elucidating the underlying mechanism implicated in the deflected function of eNOS in diabetic nephropathy.