Genetic association between endothelial nitric oxide synthase and Alzheimer disease

Evidence suggests that vascular and inflammatory factors may be important in the etiology of Alzheimer disease (AD). The Glu/Glu genotype at the Glu298Asp variant of the endothelial nitric oxide synthase (NOS3) gene has been tested for association with AD in several Caucasian and Asian populations, with conflicting results. We tested the Glu298Asp variant for association in African American and Caucasian AD patients, unaffected siblings, and unrelated controls from the MIRAGE Study. To explore whether the inconsistent results in previous studies might be due to linkage disequilibrium with a polymorphism or haplotype not previously tested, we genotyped 10 additional NOS3 single nucleotide polymorphisms (SNPs) spanning 25.3 kb. Finally, we compiled results of previous studies of Glu298Asp using meta-analysis, to determine whether the aggregate studies support an association between Glu298Asp and AD. We found that the Glu298 allele was associated with higher risk of AD in the MIRAGE African American (p = 0.002) but not Caucasian (p = 0.9) groups. None of the additional SNPs were associated with AD in the Caucasians, whereas two showed evidence for association in the African Americans. The meta-analysis showed a small effect of the Glu298Asp GG genotype on AD risk across all studies (summary odds ratio = 1.15, 95% confidence interval: 0.97-1.35) and significant heterogeneity of this association among studies (p = 0.02).     

No evidence for association of the inducible nitric oxide synthase promoter polymorphism with Trypanosoma cruzi infection

The purpose of the present study was to address the possible contribution of the (CCTTT)n microsatellite polymorphism in the NOS2 promoter region to the susceptibility to chronic Trypanosoma cruzi infection and to Chagas' disease related cardiomyopathy. We determined the (CCTTT)n genotypes in a sample of 76 serologically positive chagasic individuals and in 78 healthy controls. No statistically significant differences were observed between total chagasic patients and healthy controls with regard to frequency of the (CCTTT)n microsatellite repeat of any given length. Likewise, we found no differences in the distribution of the (CCTTT)n microsatellite repeats between seropositives without manifestations of the disease and those with chagasic cardiomyopathy. Our data suggest that the NOS2 promoter pentanucleotide microsatellite polymorphisms analyzed do not play a major role in the pathogenesis of chronic T. cruzi infection in this Peruvian sample.     

Association analysis of TG repeat polymorphism of the neuronal nitric oxide synthase gene with essential hypertension

The nitric oxide synthase (NOS) gene is thought to be involved in essential hypertension because nitric oxide is implicated in endothelium-mediated or nitroxidergic neuron-mediated vasodilation. Using simple tandem repeat DNA polymorphism of the neuronal constitutive NOS (nNOS) gene, we carried out an association study in patients with essential hypertension. One hundred and thirty-one patients with essential hypertension and 147 subjects with normal blood pressure were studied. Polymerase chain reaction was applied to amplify the TG repeat site in the nNOS gene, and alleles based on the TG repeat number were determined. Eight alleles were identified in this study of Japanese subjects. Overall distributions of allele frequencies in the two groups were not significantly different. Thus, the genes detected by examination of this microsatellite polymorphism in the nNOS gene are not associated with essential hypertension.     

No association of C677T methylenetetrahydrofolate reductase and an endothelial nitric oxide synthase polymorphism with recurrent pregnancy loss

PROBLEM: It is controversial whether polymorphisms of methylenetetrahydrofolate reductase (MTHFR) and the endothelial nitric oxide synthase (eNOS) are associated with recurrent pregnancy loss. METHOD OF STUDY: We studied the frequency of the C677T polymorphism of MTHFR and a eNOS gene polymorphism, as well as the plasma levels of homocysteine and NO, in 85 cases with a history of two or more unexplained embryonal losses, 40 patients suffering fetal loss and 76 controls. RESULTS: The frequency of the MTHFR gene T allele, which has been reported to be associated with miscarriages, in patients suffering fetal loss was rather significantly lower than in controls whereas there was no difference in the frequency of the eNOS gene A allele. There were no differences in the plasma homocysteine levels among the three groups. However, the NO concentrations in the embryonal loss and fetal loss groups were significantly higher than that in controls. CONCLUSION: We conclude that the NO concentration but not the polymorphism of MTHFR and eNOS gene and hyperhomocysteinemia are associated with recurrent pregnancy loss in Japanese.     

Neuronal nitric oxide synthase gene polymorphism and IgE-mediated allergy in the Central European population

BACKGROUND: Several findings suggest that nitric oxide (NO) plays a significant role in the regulation of the Th1/Th2 balance and contributes to the development of allergic diseases. Our study investigates a possible association of C/T transition located 276-bp downstream from the translation termination site in exon 29 of the human nitric oxide synthase type 1 (NOS1) gene with immunoglobulin E (IgE)-mediated allergic diseases in the Czech population. METHODS: The study included 688 subjects - 368 patients with clinically manifested allergic diseases and 320 unrelated controls with negative familial history of asthma/atopy. The NOS1 genotypes were determined by polymerase chain reaction (PCR) and restriction analysis by Eco72I. RESULTS: No significant differences were found for allele or genotype frequencies of the 5266 C/T polymorphism in exon 29 of the NOS1 gene between IgE-mediated allergic diseases (or asthma alone) and healthy subjects. However, this common polymorphism showed a significant association with signs of atopy, especially with total serum IgE levels [log(e) IgE levels (mean +/- SD): CC genotype = 4.34 +/- 1.40; CT genotype = 4.58 +/- 1.53; TT genotype = 5.01 +/- 1.61; P < 0.05). CONCLUSIONS: Our findings suggest that NOS1 gene may participate in the pathogenesis of high total serum IgE levels in allergic diseases in our population. These findings provide support for NOS1 as a candidate gene for IgE-mediated allergy.     

Endothelial nitric oxide synthase gene polymorphism in women with idiopathic recurrent miscarriage

BACKGROUND: Lack of endothelium-derived nitric oxide is associated with vasospasm and vascular infarction. We investigated the relationship between idiopathic recurrent miscarriage and a polymorphism of the gene encoding endothelial nitric oxide synthase (NOS3). METHOD: In a prospective case-control study, 105 women with idiopathic recurrent miscarriage and 91 healthy controls were investigated. We used the polymerase chain reaction to identify the different alleles of a 27 base pair tandem repeat polymorphism in intron 4 of the NOS3 gene. RESULTS: The wild type B allele was identified on 329 out of 392 chromosomes (frequency 0.84). The polymorphic A allele was present on 63 chromosomes (frequency 0.16). The genotype frequencies were as follows: 68% (B/B), 31% (A/B) and.5% (A/A). The distribution of genotype frequencies was significantly different between the study and control groups for allele A/B heterozygotes (NOS3(A/B)) (36.7 versus 23.8%, P = 0.03, OR 1.6, 95% CI 1.1--3.8). Only one individual was homozygous for the A allele (NOS3(A/A)). She was in the study group. Between women with primary and secondary recurrent miscarriages, no statistically significant difference between the distribution of NOS3(A/B) genotypes (28 versus 34%) was observed. CONCLUSIONS: These data support a role for the NOS3 gene as a genetic determinant of the risk of idiopathic recurrent miscarriage.     

Association between -786TC polymorphism in the endothelial nitric oxide synthase gene and hypertension in the Tunisian population

Background

Nitric oxide (NO) is produced by endothelial cells and serves as a potent vasodilator. Several lines of evidence have shown that NO plays an important role in the regulation of blood pressure and regional blood flow. Recent genetic studies have shown an association between the -786TC polymorphism in the endothelial nitric oxide synthase gene (NOS3) and coronary artery diseases, but any possible association with hypertension has been controversial. In the present study, we examined a possible association between the -786TC polymorphism of the NOS3 gene and hypertension in a sample of the Tunisian population.

Methods

A total of 288 unrelated Tunisian patients with hypertension and 373 normotensive subjects were included in the study. The -786TC gene polymorphism was analyzed by PCR-RFLP.

Results

A significant difference in genotype distribution and allele frequency was observed between patients and controls. Patients with hypertension had a frequency of 19.7% for CC genotype, 52.9% for TC genotype and 27.3% for TT genotype. The control had a frequency of 14.7% for the CC genotype, 47.2% for the TC genotype and 38.1% for the TT genotype (χ² = 9.09, p = 0.01). The hypertension patient group showed a significant higher frequency of the C allele compared to the controls (0.46 vs. 0.38; χ² = 8.26, p = 0.004). The odds ratio of hypertension for C vs. T allele frequencies was statistically significant 1.59 (1.14–2.21) at 95% CI, p = 0.004 in men, whereas it was non-significant in women 1.21 (0.87–1.67), p = 0.23.

Conclusion

The present study showed a significant and independent association between the -786TC gene polymorphism (presence of C allele) and hypertension in the Tunisian population.     

Magnetic resonance and biochemical studies during pentylenetetrazole-kindling development: the relationship between nitric oxide, neuronal nitric oxide synthase and seizures

The major aim of this study was to elucidate the role of nitric oxide (NO) in the development of pentylenetetrazole (PTZ)-kindling as an animal model of primary generalized epilepsy. The daily administration of PTZ is associated with an increase in the amount of neuronal nitric oxide synthase (nNOS). NO generation was measured directly by in vivo and ex vivo electron paramagnetic resonance on rodents undergoing progressive convulsions. We found that primary generalized epilepsy is caused by NO induction during the persistent up-regulation of nNOS expression, but that NO induction is not associated with severe generalized seizures following long-term kindling phenomena after PTZ withdrawal. Morphological changes in the brain structure of rats were measured by magnetic resonance imaging during epileptic convulsions induced by repetitive administration of PTZ. Cerebellum volume for kindled rats decreased 20% but not in rats treated with the nNOS inhibitor, 3Br-7NI, suggesting that generation of NO in the cerebellum is related to decrease in cerebellum volume following PTZ-kindling.     

Association of plasma nitric oxide concentration and endothelial nitric oxide synthase T-786C gene polymorphism in coronary artery disease

Nitric oxide (NO) is synthesized from l-arginine by endothelium nitric oxide synthase (NOS3) and plays important roles in many physiologic and pathologic processes. NO involved in the pathogenesis of coronary atherosclerosis. In the present study we hypothesized that polymorphisms of NOS gene might be associated with increased risk of coronary artery disease (CAD) and plasma NO concentrations. The eNOS gene polymorphism was investigated in 241 unrelated CAD patients with positive coronary angiograms and 261 ages matched control subjects without a history of symptomatic CAD. The NOS3 gene polymorphisms were analyzed by RFLP. Plasma NO, lipid profile and other risk factors were also assessed. The genotype frequencies for T-786C polymorphism differed significantly between CAD patients and controls (p=0.041). The mean plasma NO(x) concentrations showed significant differences according to genotypes of T-786C polymorphism in total population only. The mean plasma NO(x) increased in those individuals that are homozygote for C allele in promoter compared with those individuals are heterozygote for this allele and homozygote for T allele in total population and Controls, but no in CAD patients. The present study provides evidences that T-786C polymorphism of the NOS3 gene is associated with CAD. T-786C polymorphism was not associated with increased plasma NO in CAD patients.     

The association between endothelial nitric oxide synthase gene G894T polymorphism and hypertension in Han Chinese: a case-control study and an updated meta-analysis

Background: The G894T (rs1799983) polymorphism in endothelial nitric oxide synthase (eNOS/NOS3) gene has been implicated in susceptibility to essential hypertension (EH) in some studies, but no clear consensus has been reached in the Chinese population.

Aims: This study aimed to investigate the association of the G894T polymorphism and EH in Han Chinese.

Subjects and methods: First, a case-control study was performed involving 1525 subjects in northern Han Chinese to study the association between G894T variants and EH and then a meta-analysis was conducted of all available studies in Han Chinese. A total of 25 studies comprising 13?443 subjects were finally included in this meta-analysis.

Results: The present case-control study failed to show significant association of G894T variant with EH in northern Han Chinese. The subsequent meta-analysis showed that this polymorphism might be associated with EH in Han Chinese (p?p?p?=?0.12, OR?=?1.16). The meta-regression analysis suggested that the geographic difference of subjects was related to heterogeneity (p?=?0.029).

Conclusions: The relationship between the G894T polymorphism and hypertension in Han Chinese may be attributed to the difference in geographic background of subjects. It is necessary to carry out further research with a large sample size and focusing on gene–environment interactions.     

载脂蛋白E基因多态性与中国人阿尔茨海默病和颈动脉粥样硬化相关性研究

为了探讨中国散发性阿尔茨海默病（SAD)颈动脉粥样硬化（CAS）与ApoE基因多态性的关系,应用聚合酶链式反应－限制性片段长度多态性（PCR－RFLP）技术检测46名SAD患者、31名CAS患者及50名正常老年人的ApoE基因多态性分布特征。结果显示SAD组及CAS组ApoE ε4等位基因频率均高于对照组（P＜0．05）;SAD组为15．2％,CAS组为14．5％,对照组为3．0％,但CAS组ApoEε2等位基因频率明显高于SAD组（P＜0．05）;CAS组为41．9％,SAD组为21．7％本研究提示,ApoE4等位基因是SAD和CAS的共同危险因素,但ApoE2等位基因对CAS病人患AD具有保护作用。     

Susceptible and protective endothelial nitric oxide synthase gene polymorphism in alopecia areata in the Kuwaiti population

Alopecia areata (AA) is a chronic inflammatory disease with evidence of T-cell involvement that causes hair follicle "immune privilege collapse". Nitric monoxide was shown to contribute in the pathogenesis of AA. We are investigating evidence for the association of eNOS gene polymorphism with AA. Genomic DNA was extracted from 176 subjects, 87 Kuwaiti AA patients and 89 matched (for ethnicity, gender and age) healthy controls. A variable number tandem repeat (VNTR) located in intron-4 of the eNOS gene consisting of either four or five (27-base pair) repeats was analyzed by polymerase chain reaction and electrophoresis fragment analysis using ABI 3100 genetic analyzer. Haploview and GenePOP software were used for data analysis. A significant association was found between the intron-4 27 bp-VNTR and AA, where 4b was identified as the risk allele had (chi(2) = 4.42, p = 0.035, OR = 2.03). Genotype (4b/4b) showed a significant association with susceptibility to AA and have a frequency of 22% higher in AA patients than in healthy controls (71 vs 49%) and a chi(2) = 6.39, (p = 0.011, OR = 2.63). We report a significant association of a polymorphism within the eNOS gene and susceptibility to AA.     

Susceptible and protective endothelial nitric oxide synthase gene polymorphism in alopecia areata in the Kuwaiti population

Alopecia areata (AA) is a chronic inflammatory disease with evidence of T-cell involvement that causes hair follicle “immune privilege collapse”. Nitric monoxide was shown to contribute in the pathogenesis of AA. We are investigating evidence for the association of eNOS gene polymorphism with AA. Genomic DNA was extracted from 176 subjects, 87 Kuwaiti AA patients and 89 matched (for ethnicity, gender and age) healthy controls. A variable number tandem repeat (VNTR) located in intron-4 of the eNOS gene consisting of either four or five (27-base pair) repeats was analyzed by polymerase chain reaction and electrophoresis fragment analysis using ABI 3100 genetic analyzer. Haploview and GenePOP software were used for data analysis. A significant association was found between the intron-4 27 bp-VNTR and AA, where 4b was identified as the risk allele had (χ² = 4.42, p = 0.035, OR = 2.03). Genotype (4b/4b) showed a significant association with susceptibility to AA and have a frequency of 22% higher in AA patients than in healthy controls (71 vs 49%) and a χ² = 6.39, (p = 0.011, OR = 2.63). We report a significant association of a polymorphism within the eNOS gene and susceptibility to AA.     

内皮型一氧化氮合酶基因第7外显子894位点多态性与妊娠期高血压疾病

目的探讨内皮型一氧化氮合酶基因(endothelia n itric oxide synthase,eNOS)第7外显子894位点多态性现象与妊娠期高血压疾病(hypertensive d isorder comp licating pregnancy)的相关性及其在发病机制中的作用。方法应用聚合酶链反应-限制性片段长度多态性技术检测妊娠期高血压疾病患者和健康孕妇的eNOS基因第7外显子894位点多态性。对两组之间的基因型和等位基因频率进行比较。采用W estern b lot方法分别检测胎盘中eNOS蛋白含量在正常组和病例组之间、病例组中两种基因型之间是否存在表达水平的差异。结果T等位基因频率在正常孕妇组为6.87%,妊娠期高血压疾病组为23.00%(χ2=14.01,P=0.001,OR=4.05 95%可信区间为1.88~8.74),TG TT基因型频率在两组分别为13.75%和36.00%,χ2=8.79,P=0.003;OR=3.53 95%可信区间为1.49~8.33)差异有统计学意义。病例组中eNOS蛋白表达低于正常组,病例组中GG基因型组表达水平高于TG TT组(P<0.01)。结论eNOS基因第7外显子894位点多态性与妊娠期高血压疾病具有相关性,该位点的突变可引起eNOS蛋白表达降低,是引起妊娠期高血压疾病的可能机制。     

Nitric oxide-mediated mechanism of neuronal nitric oxide synthase and inducible nitric oxide synthase expression during hypoxia in the cerebral cortex of newborn piglets

Previously, we have shown that hypoxia results in increased generation of nitric oxide free radicals in the cerebral cortex of newborn piglets that may be due to up-regulation of nitric oxide synthases, neuronal nitric oxide synthase and inducible nitric oxide synthase. The present study tests the hypothesis that hypoxia results in increased expression of neuronal nitric oxide synthase and inducible nitric oxide synthase in the cerebral cortex of newborn piglets and that the increased expression is nitric oxide-mediated. Newborn piglets, 2-4 days old, were divided to normoxic (n=4), hypoxic (n=4) and hypoxic-treated with 7-nitro-indazole-sodium salt, a selective neuronal nitric oxide synthase inhibitor (hypoxic-7-nitro-indazole-sodium salt, n=6, 1 mg/kg, 60 min prior to hypoxia). Piglets were anesthetized, ventilated and exposed to an FiO2 of 0.21 or 0.07 for 60 min. Cerebral tissue hypoxia was documented biochemically by determining ATP and phosphocreatine. The expression of neuronal nitric oxide synthase and inducible nitric oxide synthase was determined by Western blot using specific antibodies for neuronal nitric oxide synthase and inducible nitric oxide synthase. Protein bands were detected by enhanced chemiluminescence, analyzed by imaging densitometry and the protein band density expressed as absorbance (OD x mm(2)). The density of neuronal nitric oxide synthase in the normoxic, hypoxic and hypoxic-7-nitro-indazole-sodium salt groups was: 41.56+/-4.27 in normoxic, 61.82+/-3.57 in hypoxic (P<0.05) and 47.80+/-1.56 in hypoxic-7-nitro-indazole-sodium salt groups (P=NS vs normoxic), respectively. Similarly, the density of inducible nitric oxide synthase in the normoxic, hypoxic and hypoxic-7-nitro-indazole-sodium salt groups was: 105.21+/-9.09, 157.71+/-13.33 (P<0.05 vx normoxic), 117.84+/-10.32 (p=NS vx normoxic), respectively. The data show that hypoxia results in increased expression of neuronal nitric oxide synthase and inducible nitric oxide synthase proteins in the cerebral cortex of newborn piglets and that the hypoxia-induced increased expression is prevented by the administration of 7-nitro-indazole-sodium salt. Furthermore, the neuronal nitric oxide synthase inhibition prevented the inducible nitric oxide synthase expression for a period of 7 days after hypoxia. Since administration of 7-nitro-indazole-sodium salt prevents nitric oxide generation by inhibiting neuronal nitric oxide synthase, we conclude that the hypoxia-induced increased expression of neuronal nitric oxide synthase and inducible nitric oxide synthase is mediated by neuronal nitric oxide synthase derived nitric oxide. We speculate that during hypoxia nitric oxide-mediated up-regulation of nitric oxide synthases will continue the perpetual cycle of nitric oxide generation-->NOS up-regulation-->nitric oxide generation resulting in hypoxic neuronal death.     

血管紧张素转换酶基因多态性与中国汉族迟发性阿尔茨海默病的关系

目的：探讨血管紧张素转换酶（angiotensin I converting enzyme，ACE）基因插入（I）/缺失（D）多态性与阿尔茨海默病（Alzheimer disease，AD）的关系以及高血压对这种关系的影响。方法：采取病例-对照研究的方法，对象为96个符合精神疾病诊断和统计手册第4版（DSM-IV）诊断的AD病例和96名来自同一地区的性别、年龄匹配的非AD对照，用聚合酶链反应扩增，扩增产物经琼脂糖电泳溴化乙锭染色，进行多态性检测。结果：在病例和对照之间ACE基因型和等位基因分布差异有显著性，同样在有高血压的AD患者和对照之间基因型分布的差异有显著性；但血压正常的AD患者和对照之间基因型分布差异无显著性。结论：ACE基因的多态性与AD发病风险有关，但II基因型作为危险因素仅限于高血压的AD患者。     

Immunohistochemical localisation of neuronal nitric oxide synthase in the rainbow trout kidney

The distribution of nitrergic nervous structures in the trout kidney was studied by peroxidase-linked ABC immunostaining procedures using a polyclonal antibody raised against the neuronal isoform of nitric oxide synthase. The nitrergic plexus reaches the kidney along the vasculature, mainly running with the postcardinal vein where nitrergic fibres, microganglia like cellular clusters and isolated neurones were detected. The atubular head-kidney only showed isolated nitrergic fibres close to the larger arteries. On the other hand, the collecting tubules, collecting ducts, large arteries and glomerular arterioles of the tubular middle and posterior trunks were innervated by nitrergic fibres even though immunoreactive neurones were also observed in close apposition to some tubular elements and large arteries. These results suggest that, according to morphofunctional differences between the fish and mammalian kidneys, nitrergic neural structures may be involved in the control of particular renal functions in the rainbow trout.