Endothelial nitric oxide synthase gene is associated with diabetic macular edema in type 2 diabetes

OBJECTIVE: We examined the endothelial nitric oxide (eNOS) gene polymorphisms to assess its possible association with diabetic retinopathy and macular edema. RESEARCH DESIGN AND METHODS: A total of 226 patients with type 2 diabetes and 186 healthy subjects were studied. Type 2 diabetic patients consisted of 110 patients without retinopathy, 46 patients with nonproliferative diabetic retinopathy, and 71 patients with proliferative diabetic retinopathy. Diabetic macular edema was present in 48 patients. Three polymorphisms of the eNOS gene were determined: T-786C in the promoter region, 27-bp repeat in intron 4, and Glu298Asp in exon 7. RESULTS: Close linkage disequilibrium was observed between the T-786C polymorphism and the 27-bp repeat, as has been previously reported, but Glu298Asp was not in linkage disequilibrium with the other two polymorphisms. The eNOS gene polymorphisms were not significantly associated with the presence of retinopathy or with retinopathy severity or type 2 diabetes itself. However, by both association study and multiple logistic regression analysis, the T-786C and 27-bp repeat polymorphisms were significantly associated with a risk of developing macular edema with the -786C allele and the "a" allele increasing the risk. CONCLUSIONS: The present study suggests that the eNOS gene is a novel genetic risk factor for diabetic macular edema. The eNOS gene polymorphisms may contribute to the development of macular edema by impairing basal eNOS expression and resulting in the breakdown of the blood-retina barrier.     

Endothelial nitric oxide synthase haplotypes are associated with features of metabolic syndrome

BACKGROUND: The metabolic syndrome, a cluster of several metabolic disorders, is increasingly being recognized as a risk factor for cardiovascular disease. Endothelium-derived nitric oxide facilitates skeletal muscle glucose uptake, and data from animal models indicate that endothelial nitric oxide synthase (eNOS) gene-null mice present with a phenotype of insulin resistance, hypertension, and hypertriglyceridemia, much like that observed in humans with metabolic syndrome. We used haplotype tagging single nucleotide polymorphisms (htSNPs) to investigate the role of genetic variation in the eNOS gene (NOS3) in metabolic syndrome in humans. METHODS: We recruited 738 unrelated persons from a cross-sectional population-based epidemiological survey in the province of Segovia in Central Spain (Castille). Metabolic syndrome was defined according to the recently modified National Cholesterol Education Program Adult Treatment Panel III guidelines. RESULTS: Haplotype analysis showed a statistically significant association between some NOS3 gene variants and features of metabolic syndrome. Relative to the most common haplotype, 121, the haplotype 212 was associated with an increased odds ratio (OR) for metabolic syndrome [OR = 1.81, 95% confidence interval (CI) 1.15-2.84], and for decreased HDL-cholesterol concentrations (OR 1.52, 95% CI 1.01-2.29), and with increased mean values for the homeostasis model assessment of insulin resistance (P = 0.043), and triglycerides (P = 0.026). CONCLUSIONS: Our results suggest that genetic variation at the eNOS locus is associated with features of metabolic syndrome, and might represent a new genetic susceptibility component for insulin resistance, hypertriglyceridemia, and low HDL-cholesterol concentrations.     

内皮型一氧化氮合酶基因转染对移植人工血管内膜增生的作用

目的:平滑肌细胞增殖移行和血小板激活导致血栓形成是移植血管再狭窄的主要原因,一氧化氮可以抑制上述生物反应,但内皮型一氧化氮合酶基因转染是否抑制种植了平滑肌细胞的人工血管内膜增生还未得到证实.实验拟进一步观察内皮型一氧化氮合酶基因转染对种植平滑肌细胞的人工血管内膜增生的影响.方法:实验于2006-04/2007-05在西安交通大学医学院中心实验室及分子生物学实验室完成.①实验材料:1月龄新西兰大白兔1只,用来获取平滑肌细胞.成年新西兰大白兔18只,随机数字表法分成3组,每组6只.正常细胞组移植未种植细胞的人工血管;LacZ转染组移植种植转染lacZ的平滑肌细胞的人工血管,内皮型一氧化氮合酶转染组移植种植内皮型一氧化氮合酶的平滑肌细胞的人工血管.②实验方法:构建含有报道基因lacZ和内皮型一氧化氮合酶基因的假型反转录病毒载体小鼠白血病病毒/疱疹性口炎病毒G糖蛋白,并转染平滑肌细胞.将转染了基因的细胞种植在人工血管上,并用血管旁路移植的方法植入兔腹主动脉.③实验评估:测定转染内皮型一氧化氮合酶基因及LacZ基因细胞培养上清中一氧化氮含量.血管植入30,100 d 后X-gal染色及苏木精-伊红染色观察人工血管上的平滑肌细胞,同时显微镜下测量每段血管内膜增生的厚度.结果:纳入成年新西兰大白兔18只,均进入结果分析.①内皮型一氧化氮合酶转染组一氧化氮含量明显高于未转染的正常细胞组(P ＜ 0.05).平滑肌细胞转染lacZ基因后经X-gal染色,倒置显微镜下可见转染了基因的细胞被染成蓝色.②血管植入30 d,与正常细胞组比较,LacZ转染组和内皮型一氧化氮合酶转染组内膜厚度差异无显著性(P ＞ 0.05);100 d后,内皮型一氧化氮合酶转染组内膜厚度与正常细胞组无明显差异,与LacZ转染组相比较,差异显著(P ＜ 0.05).结论:内皮型一氧化氮合酶基因转染抑制了种植平滑肌细胞的人工血管内膜增生.     

内皮型一氧化氮合酶基因转染对移植人工血管内膜增生的作用

目的：平滑肌细胞增殖移行和血小板激活导致血栓形成是移植血管再狭窄的主要原因，一氧化氮可以抑制上述生物反应，但内皮型一氧化氮合酶基因转染是否抑制种植了平滑肌细胞的人工血管内膜增生还未得到证实。实验拟进一步观察内皮型一氧化氮合酶基因转染对种植平滑肌细胞的人工血管内膜增生的影响。 方法：实验于2006-04／2007—05在西安交通大学医学院中心实验室及分子生物学实验室完成。①实验材料；1月龄新西兰大白兔1只，用来获取平滑肌细胞。成年新西兰大白兔18只，随机数字表法分成3组，每组6只。正常细胞组移植未种植细胞的人工血管；LacZ转染组移植种植转染lacZ的平滑肌细胞的人工血管，内皮型一氧化氮合酶转染组移植种植内皮型一氧化氮合酶的平滑肌细胞的人工血管。②实验方法：构建含有报道基因lacZ和内皮型一氧化氮合酶基因的假型反转录病毒载体小鼠白血病病毒，疱疹性口炎病毒G糖蛋白，并转染平滑肌细胞。将转染了基因的细胞种植在人工血管上，并用血管旁路移植的方法植入兔腹主动脉。③实验评估：测定转染内皮型一氧化氮合酶基因及LacZ基因细胞培养上清中一氧化氮含量。血管植入30，100d后X—gal染色及苏木精一伊红染色观察人工血管上的平滑肌细胞，同时显微镜下测量每段血管内膜增生的厚度。 结果：纳入成年新西兰大白兔18只，均进入结果分析。①内皮型一氧化氮合酶转染组一氧化氮含量明显高于未转染的正常细胞组（P〈0．05）。平滑肌细胞转染lacZ基因后经X—gal染色，倒置显微镜下可见转染了基因的细胞被染成蓝色。②血管植入30d，与正常细胞组比较，LacZ转染组和内皮型一氧化氮合酶转染组内膜厚度差异无显著性（P〉0．05）；100d后，内皮型一氧化氮合酶转染组内膜厚度与正常细胞组?     

Endothelial nitric oxide synthase gene polymorphisms and risk of coronary artery disease

BACKGROUND: Endothelial nitric oxide synthase (eNOS) could be a candidate gene for coronary artery disease (CAD). This study investigated the relationship of the eNOS Glu(298)-->Asp and T(786)-->C polymorphisms with the presence and severity of CAD in the Italian population. METHODS: We enrolled 415 unrelated individuals who underwent coronary angiography. The severity of CAD was expressed by means of the Duke score. The eNOS Glu(298)-->Asp and T(786)-->C variants were analyzed by PCR. RESULTS: There was significant linkage disequilibrium between the two eNOS polymorphisms (P <0.0001). Both variants were significantly associated with the occurrence and severity of CAD (P = 0.01 and 0.004 for Glu(298)-->Asp and T(786)-->C, respectively). The risk of CAD was increased among individuals homozygous for the C allele of the T(786)-->C polymorphism compared with individuals homozygous for the T allele (odds ratio = 2.5; P <0.01) and was independent of the other common risk factors (P = 0.04). Moreover, individuals with both the Asp/Asp genotype of the Glu(298)-->Asp polymorphism and at least one C allele of the T(786)-->C variant in the promoter region of the eNOS gene had an increased risk of CAD (odds ratio = 4.0; P <0.001) and a significantly higher mean Duke score (26.2 +/- 2.9 vs 45.2 +/- 3.7; P = 0.002) compared with individuals with the TT genotype and the Glu allele. CONCLUSIONS: The present study provides evidence that the Glu(298)-->Asp and T(786)-->C polymorphisms of the eNOS gene are associated with the presence and severity of angiographically defined CAD in the Italian population and that those individuals carrying both eNOS variants simultaneously might have a higher risk of developing CAD.     

The Glu298ASP polymorphism of the endothelial nitric oxide synthase gene is associated with premature ST elevation myocardial infarction in Mexican population

BackgroundThe polymorphism Glu298Asp of endothelial nitric oxide (eNOS) gene has been associated with hypertension and coronary artery disease in several populations worldwide, but results are still controversial. We examined the possible association of the Glu298Asp with premature ST elevation myocardial infarction (STEAMI) in young Mexican population.MethodsIn a case–control study 180 unrelated patients with STEAMI ≤ 45 years who were admitted to a cardiovascular intense care unit and 180 apparently healthy controls matched by age and gender were recruited from January 2006 to June 2009. The polymorphism Glu298Asp was determined in all participants by a polymerase chain-reaction-restriction fragment length polymorphism assay (PCR-RFLP).ResultsThere was a significant difference in the genotype distribution between 2 groups (P = 0.001). The allele Asp occurred more frequently in the patients group (P = 0.001). There were independent factors for STEAMI: the Asp allele (OR 2.2, 95% CI 1.1–3.5, P = 0.03), smoking (OR 5.0, 95% CI 3.1–8.2, P < 0.001), hypertension (OR 2.0, 95% CI 1.0–3.5, P = 0.03), family history of cardiovascular disease, (OR 3.7, 95% CI 2.0–4.6, P = 0.02), and dyslipidemia (OR 3.4, 95% CI 2.0–6.3, P = 0.02).ConclusionsThe Asp allele from the Gu298Asp polymorphism represents an independent risk factor for premature STEAMI in Mexican Mestizo population.     

冠心病合并抑郁患者内皮型一氧化氮合酶基因G894T多态性分析

目的探讨冠心病合并抑郁与内皮型一氧化氮合酶基因G894T位点多态性的关系。方法冠心病患者217例,分为冠心病合并抑郁组39例和冠心病组178例,选择同期抑郁症患者45例(抑郁症组)与健康体检者85名(对照组)。检测4组内皮型一氧化氮合酶基因G894T位点多态性,并分析4组间差异。结果 4组内皮型一氧化氮合酶基因G894T位点GT杂合基因型和T等位基因频率分布两两比较差异均无统计学意义(P>0.05)。结论冠心病合并抑郁与一氧化氮合酶基因G894T位点多态性无明显相关性。     

Endothelial nitric oxide synthase gene intron 4 polymorphism in type 2 diabetes mellitus.

INTRODUCTION: Endothelial nitric oxide synthase (ecNOS) is a key regulator of vascular nitric oxide production. Polymorphism in intron 4 of the ecNOS gene is implicated in cardiovascular and renal diseases. We investigated a potential involvement of this polymorphism in the development of type 2 diabetes mellitus and its renal complications. METHODS: This preliminary study involved 410 individuals with type 2 diabetes and 330 healthy control subjects. From the diabetes group 178 patients had diabetic nephropathy. All subjects were genotyped for the ecNOS4 polymorphism by the polymerase chain reaction (PCR) followed by gel electrophoresis. Genotype and allele frequencies were compared between diabetes patients with and without nephropathy and the control group. All calculations were performed using the Statistical Package for the Social Sciences (SPSS, Inc., Chicago, IL, USA) for Windows 5.0. The chi-square test and Fisher's exact test were used for case-control comparisons. The Kruskal-Wallis test was used for the comparison of subgroups of patients with diabetes. RESULTS: The analysis revealed that patients with diabetes, regardless of their nephropathy status, were significantly different in genotype distribution and 4a allele frequencies compared with controls (p < 0.05). The frequency of aa genotype was 8.2% in diabetic patients without nephropathy, 8.4% with those with nephropathy and 1.2% in controls. The 4a allele showed a significant effect on diabetic nephropathy, with odds ratio of 2.24 (95% confidence interval 1.12-3.40). There were no significant differences in the 4a allele frequency between the normotensive and hypertensive patients with diabetes. CONCLUSION: Our results suggest that the ecNOS gene polymorphism can serve as a useful genetic marker of increased susceptibility to type 2 diabetes and its renal complications.     

2型糖尿病患者后代内皮细胞型一氧化氮合酶基因多态性研究

背景2型糖尿病患者内皮细胞型一氧化氮合酶(endothelial constitutivenitric oxide synthase,ecNOS)的第四内含子的a等位基因(4a等位基因)频率增高且与血管内皮功能减低有关.目的探讨2型糖尿病和糖耐量正常的2型糖尿病一级亲属ecNOS基因多态和血浆一氧化氮并探讨他们的关系.设计以诊断为依据,非随机对照试验.地点、对象和方法正常对照组67例为河北省人民医院健康查体并自愿参加研究者,男33例,女34例;一级亲属组为本院代谢门诊就诊的2型糖尿病患者子女98例,男48例,女50例;糖尿病组为本院老年内分泌科就诊的2型糖尿病患者85例,男40例,女45例.纳入标准符合1999年WHO 2型糖尿病诊断标准.排除标准无糖尿病神经病变及血管病变;无血缘关系;无严重高脂血症等.应用PCR扩增技术测定ec-NOS基因型,用硝酸还原酶法测定一氧化氮.主要观察指标3组研究对象的ecNOS基因型、一氧化氮水平以及空腹胰岛素、总胆固醇、三酰甘油、体质量指数、腰臀比、空腹血糖及血红蛋白.结果①糖尿病组和一级亲属组与对照组相比a/a+a/b基因型频率和4a等位基因频率呈增高趋势,但差异无显著性意义(P＞0.05).②对照组、一级亲属组、糖尿病携带4a等位基因者的血浆一氧化氮水平[(68.00±15.9),(60.75±17.64),(61.63±18.26)μmol/L]显著低于不带4a等位基因者[(98.30±25.1),(83.70±26.37),(75.15±29.38),t=-3.289,-3.432,P＜0.01,t=-2.432,P＜0.05].结论2型糖尿病和糖耐量正常的2型糖尿病一级亲属血浆一氧化氮降低存在基因依赖性.     

内皮型一氧化氮合酶基因转染对移植人工血管内膜增生的作用

背景：平滑肌细胞增殖移行和血小板激活导致血栓形成是移植皿管再狭窄的主要原因，一氧化氮可以抑制上述生物反应，但内皮型一氧化氮合酶基因转染是否可以抑制种植平滑肌细胞的人工血管内膜增生还未得到证实。 目的：拟进一步观察内皮型一氧化氮合酶基因转染对种植平滑肌细胞的人工血管内膜增生的影响。 设计、时间及地点：重复观察测量，于2006-04／2007-05在西安交通大学医学院中心实验室及分子生物学实验室完成。 材料：1月龄新西兰大白兔1只，用来获取平滑肌细胞。成年新西兰大白兔18只．随机分成3组，正常对照组植入未转染的人工血管．LacZ转染组植入种植转染lacZ的平滑肌细胞的人工血管，内皮型一氧化氮合酶转染组植入种植内皮型一氧化氮合酶的平滑肌细胞的人工血管。6只/组。 方法：构建含有报道基因lacZ和内皮型一氧化氮合酶基因的假型反转录病毒载体小鼠白血病病毒/疱疹性口炎病毒G糖蛋白，并转染平滑肌细胞。将转染了基因的细胞种植在人工血管上，并用血管旁路移植的方法植入兔腹主动脉。 主要观察指标：瓜氨酸法检测细胞培养上清中一氧化氮含量。移植血管内膜X-gal染色观察，种植的平滑肌细胞为蓝色，而内源性细胞为红色。显微镜下测量血管内膜增生厚度。 结果：18只兔均进入结果分析。内皮型一氧化氮合酶转染组一氧化氮含量明显高于正常对照组（P〈0．05）。转染lacZ基因的平滑肌细胞经X-gal染色呈蓝色。血管平滑肌细胞植入30d，各组内膜厚度基本相似（P〉0．05）：植入100d．正常对照组与内皮型一氧化氮合酶转染组内膜厚度基本相似（P〉0．05），两组明显均低于lacZ转染组（P〈0．05）。 结论：内皮型一氧化氮合酶基因转染可抑制种植平滑肌细胞的人工血管内膜增生。     

Interaction between -786TC polymorphism in the endothelial nitric oxide synthase gene and smoking for myocardial infarction in Korean population

BACKGROUND: Nitric oxide (NO) produced by endothelial nitric oxide synthase (eNOS) mediates endothelium-dependent vasodilation and antithrombotic action. Controversial results regarding the association of eNOS gene polymorphisms with myocardial infarction (MI) have been reported. METHODS: A total of 932 individuals living in Seoul and the suburb, Korea, were randomly selected. Genomic DNA was prepared from blood leukocytes. A GT missense mutation in exon 7 (894GT) was screened using PCR-RFLP analysis. The genotypes of 3 mutations (-786TC, -922AG, and -1468TA) in the 5'-flanking region were determined by a minisequencing protocol (SNaPshot), respectively. RESULTS: Pair-wise linkage analysis revealed that 3 mutations of -786TC, -922AG, and -1468TA were completely linked with each other (mid R:D'mid R:=1, r(2)=0.96-1.0). Furthermore, each of these mutant alleles (-786C, -922G, or -1468A), but not 894T allele, was associated with the risk of MI. Multiple logistic regression analysis revealed that each of these mutant alleles was a predictive independent risk factor for the risk of MI (odds ratio, 1.69 for dominant effects, P<0.05) after age and sex adjustments. Smoking further increased the odds ratio by 2.04 for the risk of MI when it was combined with the mutant alleles. CONCLUSION: Each of 3 mutations (-786TC, -922AG, or -1468TA) in the 5'-flanking region of eNOS gene may play a role in the pathogenesis of MI in Korean population, and also provides an evidence for a significant interaction between these mutations and smoking.     

A decline in myometrial nitric oxide synthase expression is associated with labor and delivery.

The mechanisms that maintain relative uterine quiescence during pregnancy remain largely unknown. A possible role for nitric oxide has recently emerged, however, the expression of nitric oxide synthase within human myometrium at midgestation, a time when the uterus is normally quiescent, has not been investigated. The purpose of this study was to identify cell types in human myometrium that contain inducible nitric oxide synthase (iNOS), and to examine changes in its expression during pregnancy and labor. We found that iNOS is expressed in smooth muscle cells of pregnant myometrium. Expression of iNOS was highest in myometrium of preterm not-in-labor patients. At term, iNOS expression fell by 75%, and was barely detectable in preterm in-labor or term in-labor specimens. There was no staining in the myocytes of nonpregnant myometrium. Western blotting also revealed a similar pattern of changes in iNOS expression. In summary, iNOS expression in the myocytes of human myometrium is increased greatly during pregnancy, and declines towards term or with labor. Significantly, preterm inlabor patients also had a large decline in iNOS expression. These data suggest that changes in myometrial iNOS expression may participate in the regulation of uterine activity during human pregnancy.     

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

BACKGROUND: Nitric oxide (NO) from the endothelium, produced by oxidation of l-arginine to L-citruline for the action at the endothelial nitric oxide synthase (eNOS), is considered an important atheroprotective factor. The Glu298Asp (G894T) polymorphic variant of the eNOS gene has been implicated in the development of coronary artery disease (CAD). We investigated the association between occurrence of CAD documented by angiography and the G894T polymorphism of the NOS3 gene in Chilean individuals. METHODS: A total of 112 unrelated patients with diagnosis of CAD and 72 controls were included in this study. G894T gene polymorphism was analyzed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). RESULTS: The frequency of TT homozygous genotype for G894T polymorphism was 7% in CAD patients and 1% in the control group. However, the genotype distribution and allele frequencies were not significantly different between CAD and control subjects (P>0.05). Moreover, the odds ratio for CAD associated with the T variant failed to reach statistical significance (OR=1.5; 95% CI: 0.87-2.59, P>0.05). CONCLUSION: These findings suggest that the G894T polymorphism of the eNOS gene was not associated with CAD in Chilean individuals.     

缺氧脑组织与一氧化氮及其合酶

目的:在脑缺血性损伤过程中,一氧化氮发挥着复杂的作用,多途径参与了生理和病理过程,许多实验的结论看似矛盾,但经过人们大量和细致的分析,已可以得出一些大致的规律性认识。资料来源:应用计算机检索Medline1987-01/2001-03有关一氧化氮及其合酶与缺氧脑组织关系的文献,检索词“Hypoxia,Nitricoxide,Ni-tricoxidesynthase”,并限定语言种类为English。资料选择:对所选文献进行初审,排除综述类文献及Meta分析,然后全文查找余下的文献。质量评价主要考察资料的真实性,实施过程是否严格,统计学分析是否合理。资料提炼:共检索28篇关于一氧化氮及其合酶与缺氧脑组织关系的文献,20篇文献符合纳入标准,排除的8篇文章中,4篇是因重复的同一实验,其他4篇为小样本实验结果。资料综合:在脑缺氧过程中一氧化氮起着复杂而关键的作用,在脑缺氧过程中,伴随着一氧化氮的变化。一氧化氮的释放受一氧化氮合酶的调控,一氧化氮合酶的活性与缺氧的相关因子有关。结论:一氧化氮在脑缺氧过程中起着保护与损伤双重作用,其对脑组织损伤或保护取决于脑缺氧的不同时期和一氧化氮局部含量等因素。适量的一氧化氮对脑缺氧有防护作用,而在脑缺血缺氧的大部分时期则应使用诱生型一氧化氮合酶和神经元型一氧化氮合酶的选择性抑制剂抑制一     

Tissue expression of inducible nitric oxide synthase is closely associated with resistance to Leishmania major

Previous studies with inhibitors of inducible nitric oxide synthase (iNOS) suggested that high-output production of nitric oxide (NO) is an important antimicrobial effector pathway in vitro and in vivo. Here, we investigated the tissue expression of iNOS in mice after infection with Leishmania major. Immunohistochemical staining with an iNOS-specific antiserum revealed that in the cutaneous lesion and draining lymph nodes (LN) of clinically resistant mice (C57BL/6), iNOS protein is found earlier during infection and in significantly higher amounts than in the nonhealing BALB/c strain. Similar differences were seen on the mRNA level as quantitated by competitive polymerase chain reaction. Anti-CD4 treatment of BALB/c mice not only induced resistance to disease, but also restored the expression of iNOS in the tissue. In situ, few or no parasites were found in those regions of the skin lesion and the draining LN which were highly positive for iNOS. By double labeling experiments, macrophages were identified as iNOS expressing cells in vivo. In the lesions of BALB/c mice, cells staining positively for transforming growth factor beta (TGF-beta), a potent inhibitor of iNOS in vitro, were strikingly more prominent than in C57BL/6, whereas no such difference was found for interleukin 4 or interferon gamma (IFN-gamma). In vitro, production of NO was approximately threefold higher in C57BL/6 than in BALB/c macrophages after stimulation with IFN-gamma. We conclude that the pronounced expression of iNOS in resistant mice is an important mechanism for the elimination of Leishmania in vivo. The relative lack of iNOS in susceptible mice might be a consequence of macrophage deactivation by TGF-beta and reduced responsiveness to IFN-gamma.     

Plasma nitric oxide concentrations and nitric oxide synthase gene polymorphisms in coronary artery disease

BACKGROUND: Plasma NOx (nitrate and nitrite) is a stable end product of the vasodilator NO. Several polymorphisms in the endothelial constitutive NO synthase (ecNOS) gene have been reported, including the 4a/4b VNTR polymorphism in intron 4, the E298D mutation in exon 7, and the G10-T polymorphism in intron 23. The aims of this study were to examine plasma NOx in patients with coronary artery disease (CAD) and to assess the association between plasma NOx concentrations and the three ecNOS gene polymorphisms. METHODS: Plasma NOx was measured in samples from 128 healthy controls and from 110 CAD patients at least 2 months after myocardial infarction. Three genetic polymorphisms that are known or have been suggested to be associated with plasma NOx concentration were also analyzed by PCR-restriction fragment length polymorphism. RESULTS: Median plasma NOx was significantly higher (P <0.001) in CAD patients (95.9 micromol/L) than in controls (73.8 micromol/L). Furthermore, the median plasma NOx was significantly higher (P <0.001) in hypertensive CAD patients (116.0 micromol/L) than in controls and normotensive CAD patients (86.0 micromol/L). The G-allele frequency of the G10-T polymorphism in intron 23 was significantly higher in CAD patients than in controls. Other polymorphisms showed no differences in allelic frequencies among the control and CAD groups. In controls, individuals with the E298D mutation in exon 7 (136.1 micromol/L) showed significantly higher (P = 0.001) median plasma NOx than those without this mutation (64.5 micromol/L). CONCLUSIONS: Plasma NOx was higher in hypertensive CAD patients than in normotensive CAD patients and controls. The E298D polymorphism of the ecNOS gene was associated with increased plasma NOx. Further study is needed to understand the gene expression and enzyme activity of ecNOS and their association with genotypes.     

Endothelial nitric oxide synthase (NOS) is upregulated in rapid progressive pulmonary hypertension of the newborn

Objective To provide evidence for the upregulation of endothelial nitric oxide synthase (eNOS) or inducible nitric oxide synthase (iNOS) in the assumed imbalance in the pathophysiology of rapid progressive pulmonary hypertension of the newborn (RPPHN), which is characterized by abnormal hypertrophy of the pulmonary arterioles and arteries leading to increased pulmonary vascular resistance. Furthermore, to determine the cellular source and topographic distribution of eNOS and iNOS.Material and Methods Lung biopsies were taken from two term neonates with clinical and echocardiographic evidence of RPPH and of three controls. Biopsies were obtained at an early stage of the disease as well as at post mortem and examined immunohistochemically for the presence of eNOS, iNOS and nitrotyrosine.Results The endothelial cells of pulmonary arterioles stained significantly for eNOS protein in RPPHN patients. This was not the case in the control infants. There were no differences for nitrotyrosine or iNOS between RPPHN patients and controls.Conclusion Rapid progressive pulmonary hypertension of the newborn leads to compensatory induction of eNOS synthesis specifically in endothelial cells of the pulmonary arterioles. This mechanism of compensation can lead to delayed presentation of RPPHN during the late neonatal period. Exogenous inhaled nitric oxide therapy does not lead to suppression of the endogenous synthesis of nitric oxide.     

Endothelial nitric oxide synthase protects the post-ischemic liver: potential interactions with superoxide.

Hepatic ischemia and reperfusion (I/R) continues to represent a significant cause of post-transplant liver failure. The roles that certain free radicals including nitric oxide (NO) and superoxide (O(2)(-)) play in this process are not well understood. The present study was designed to assess the role of endothelial cell nitric oxide synthase (eNOS) in I/R-induced liver injury in a murine model of hepatic I/R. Forty five minutes of partial (70%) hepatic ischemia followed by 3 and 6 h of reperfusion resulted in a significant increase in liver injury which occurred in the absence of neutrophil infiltration. eNOS-deficient mice displayed enhanced liver injury when compared to their wild type controls again in the absence of neutrophil infiltration. Interestingly, basal liver blood flow was significantly decreased in these mice when compared to controls though their blood flow during reperfusion was not significantly reduced from their wild type controls. Treatment of eNOS(-/-) mice with gadolinium chloride, a potent inhibitor of Kupffer cell function, but not superoxide dismutase, significantly reduced post-ischemic hepatocellular injury while either treatment protected the wild type mouse livers. Taken together, these data suggest that NO derived from eNOS may act to protect the post-ischemic liver possibly by suppression of Kupffer cell function and not by modulation of tissue perfusion. Further the data presented here would indicate that the protective effects conferred by SOD are related to its ability to increase the bioavailability of NO rather than by attenuating superoxide-dependent reactions. Data generated from these studies may prove useful in developing new drug therapies to treat the post-ischemic liver.