Relation of endothelial nitric oxide synthase gene to plasma nitric oxide level, endothelial function, and blood pressure in African Americans

BACKGROUND: The role of eNOS gene polymorphisms on plasma nitrite or nitrate (NOx) level, endothelial function, and blood pressure (BP) remains unclear. METHODS: We estimated the relationship of eNOS polymorphisms (the T(-786)C in the 5'-flanking promoter region, T(-786)C; 27-bp repeat in intron 4, eNOS4; and Glu298Asp in exon 7, G894T) with plasma NOx level, brachial endothelial function assessed by ultrasound measure of brachial artery flow-mediated dilation (FMD), and BP in 60 healthy African Americans, 30 men and 30 women aged 18 to 73 years. RESULTS: Among them, 73.1%, 23.9%, and 3.0% carried TT, TC, and CC of T(-786)C, respectively, 14.5%, 27.5%, 53.6%, and 1.4% carried aa, ab, bb, and bc of eNOS4 polymorphism, respectively, and 70.4%, 23.9%, and 5.6% carried GG, GT, and TT of G894T, respectively. G894T and eNOS4 were observed in linkage disequilibrium. Mean values of age, plasma NOx, FMD, systolic and diastolic BPs were not significantly different (P >.05) by eNOS polymorphisms. Plasma NO(x) level was found to be associated with systolic BP (r = 0.51, P =.03), and diastolic BP (r = 0.41, P =.08), but not with FMD, in individuals with "a" allele of eNOS4 polymorphism after adjustment for age, body mass index, serum glucose, and smoking status. CONCLUSIONS: We reveal a positive association between plasma NOx level and BP in normotensive African Americans who carry the "a" allele of eNOS4. Because the frequency of the rare allele "a" is significantly higher in African Americans than in other ethnic groups, this finding may provide a clue to understanding the genetic susceptibility to hypertension in African Americans.     

Smoking-dependent and haplotype-specific effects of endothelial nitric oxide synthase gene polymorphisms on angiographically assessed coronary artery disease in Caucasian- and African-Brazilians

The nitric oxide produced by endothelial nitric oxide synthase (eNOS) plays a pivotal role in protecting the arterial wall from damages and atherosclerosis. The T-786C, the 27-bp repeat in intron 4, and the E298D eNOS gene polymorphisms were studied in 715 Brazilian patients (447 Caucasian- and 268 African-Brazilians) who underwent coronary angiography. The -786C frequency was increased in coronary artery disease (CAD) cases with significant lesions (> or =50% luminal obstruction) when compared with lesion-free controls; this difference was detected in smokers but not in nonsmokers, both in Caucasian- (p=0.011) and African-Brazilians (p=0.005). The interaction between -786C carriers and smoking was an independent CAD predictor (OR: 2.9, 95% CI: 1.4-5.9; p=0.003) in multiple logistic regression. The 298D mutation frequency was also higher among CAD cases (p=0.036) in African-Brazilian smokers, but this effect was not independent from other variables in the regression model. Though not associated with CAD, the 4-repeat allele combined with different T-786C alleles showed protective and susceptible effects in Caucasian-Brazilian smokers. The -786C/4-repeat/298E haplotype frequency was higher (p=0.020), whereas -786T/4-repeat/298E was lower (p=0.023) in these cases. These results showed a smoking-dependent effect of the T-786C eNOS polymorphism on CAD in both Caucasian- and African-Brazilians. Additionally, the haplotype analysis revealed different eNOS haplotypes associated with protection and susceptibility to the disease.     

PAI-1基因启动子区4G/5G基因多态和Enos第4内含子a/b基因多态与糖尿病肾病的相关性研究

为探讨 PAI- 1基因启动子区 4 G/ 5 G基因多态性、一氧化氮合酶 (e NOS)第 4内含子 2 7bp插入 /缺失 (a/b)多态性与糖尿病肾病 (DN)的相关性 ,采用发色底物法测定 PAI- 1活性 ;等位基因特异性引物 PCR扩增技术测定 PAI- 1基因 4 G/ 5 G多态性 ;聚合酶链反应测定 e NOS基因第 4内含子 2 7bp的 a/ b多态性。结果显示 ,Hb A1c、SBP、TC、e NOS基因第 4内含子 a/ b多态均属 DN的独立危险因素。早期糖尿病肾病组 (DN+组 ) a等位基因及 ab基因型频率显著高于糖尿病非肾病组 (DN-组 ) (P<0 .0 5 )。DN+组血浆 PAI- 1活性明显高于 DN-组 (P<0 .0 5 ) ;4 G纯合子组 PAI- 1活性明显高于 4 G/ 5 G杂合子及 5 G纯合子组 (P<0 .0 0 5 )。2型糖尿病患者中 ,4 G纯合子和a/ b杂合子携带者 DN的相对风险明显增加 (P<0 .0 5 ) ,4 G杂合子携带者 DN的相对风险增加不明显 (P>0 .0 5 )。当 a/ b杂合子和 4 G纯合子基因多态并存时 DN的发病风险明显增加。认为 PAI- 1基因启动子区 4 G/ 5 G基因多态、e NOS基因第 4内含子 a/ b多态与 DN的发生、发展有关。两种基因多态同时存在时 ,DN的发病风险明显增加     

Allelic polymorphism in the promoter (T–786→C), but not in exon 7 (G894→T) or the variable number tandem repeat in intron 4, of the endothelial nitric oxide synthase gene is positively associated with acute coronary syndrome in the Ukrainian population

BACKGROUND: Different allelic variants of endothelial nitric oxide synthase (eNOS) can have different effects on the development of certain forms of ischemic heart disease, depending on the specific human population. The frequency of the polymorphism T(-786) --> C in the promoter, G(894)-->T in exon 7 and the variable number tandem repeat in intron 4 were assayed in patients with acute coronary syndrome compared with clinically healthy individuals in the Ukrainian population. METHODS: Polymerase chain reaction and restriction fragment length polymorphism analysis were used to detect the above mentioned variants of the eNOS gene in 221 patients with acute coronary syndrome and in 83 control subjects. RESULTS: It was shown that the percentage of normal homozygotes, heterozygotes and pathological homozygotes for the T(-786)-->C promoter polymorphism was 47.5%, 36.2% and 16.3%, respectively (controls: 48.2%, 45.8% and 6.0%; P<0.05 by chi(2) test); for the G(894)-->T polymorphism in exon 7, the percentages were 34.4%, 57.9% and 7.7%, respectively (controls: 28.9%, 67.5% and 3.6%; P>0.05); and, for the 4a/4b polymorphism in intron 4, the percentages were 64.7%, 31.2% and 4.1%, respectively (controls: 62.7%, 32.5% and 4.8%; P>0.05). CONCLUSIONS: The C/C promoter variant of eNOS can be considered a risk factor for acute coronary syndrome in the Ukrainian population.     

The 27-bp tandem repeat polymorphism in intron 4 of the endothelial nitric oxide synthase gene is not associated with coronary artery disease in a hospital-based Taiwanese population

We studied whether the 27 base pair (bp) tandem repeat polymorphism in intron 4 of the endothelial nitric oxide synthase (eNOS) gene was associated with coronary artery disease (CAD) in a hospital-based Taiwanese population. We included 219 consecutive patients who underwent coronary angiography at our institution. Two alleles, containing 4 (eNOS4a) and 5 repeats (eNOS4b), were identified after polymerase chain reaction amplifying intron 4 of the eNOS gene. The genotype frequencies for eNOS4b/b, eNOS4a/b and eNOS4a/a were 77.9, 21.5 and 0.6% in CAD subjects, and 80, 20 and 0% in control subjects (Fisher's exact test, p = 0.90), respectively. The odds ratio (OR) for CAD in patients with at least one eNOSa allele was 1.2 (0.5-2.9) after adjustment for classical CAD risk factors. The eNOS4a allele was not associated with the severity of CAD (Fisher's exact test, p = 0.90) and the occurrence of acute myocardial infarction (AMI) or unstable angina (adjusted OR 0.6, 0.3-1.6) in patients with CAD. In conclusion, the 27-bp repeat polymorphism of the eNOS gene was not associated with CAD and the occurrence of AMI or unstable angina in a hospital-based Taiwanese population.     

An additive effect of endothelial nitric oxide synthase gene polymorphisms contributes to the severity of atherosclerosis in patients on dialysis

BACKGROUND: Reduced synthesis of nitric oxide (NO) is considered a major proatherogenic mechanism in patients with end-stage renal disease (ESRD), but genetic factors impinging on this mechanism have been little studied in this population. METHODS: We tested the relationship between carotid intima-media thickness (IMT) and three endothelial NO synthase (eNOS) polymorphisms (G894T, T-786C, and 27-bp repeat in intron 4) in an ethnically and geographically homogeneous group of 147 patients with ESRD. RESULTS: The IMT was significantly thicker (P = .01) in patients with the TT genotype (G894T polymorphism) than in patients with TG or GG genotypes, and a similar association was observed for the T-786C polymorphism (P = .02). These relationships remained statistically significant (P = .02 and .01), also in multivariate models including traditional and emerging risk factors for atherosclerosis. Moreover, there was a direct association between the number of risk alleles and IMT (no risk allele: 0.97 +/- 0.22 mm, 1 risk allele: 1.03 +/- 0.20 mm, 2 risk alleles: 1.07 +/- 0.22 mm, > or =3 risk alleles: 1.23 +/- 0.36 mm, P < .001) that remained statistically significant in a multiple regression model. CONCLUSIONS: In patients on dialysis the risk alleles of G894T and T-786C polymorphisms of the eNOS gene are associated with carotid atherosclerosis. The additive effect of the two polymorphisms may contribute to the severity of atherosclerosis independently of other risk factors and of endogenous substances that influence the NO synthesis in this population.     

Both T-786C and G894T polymorphism of endothelial nitric oxide synthase affect in-vitro endothelium-dependent relaxation of internal mammary artery rings from patients with coronary artery disease.

OBJECTIVES: Polymorphisms of endothelial nitric oxide synthase (eNOS) gene in the promoter (T-786C) and exon 7 (G894T) have been suggested to attenuate endothelial function. As it is unknown whether these polymorphisms, on top of classical risk factors, further deteriorate endothelium-dependent vasomotion, we aimed to elucidate the impact of both polymorphisms on the ex-vivo vasomotor function of left internal mammary artery rings from patients with coronary artery disease (CAD) undergoing coronary bypass surgery (CABG). METHODS: Mammary artery rings from 51 consecutive patients with CAD were obtained during elective CABG. Endothelium-dependent ring relaxation was measured in vitro in an organ chamber using acetylcholine (10 to 3 x 10 mol/l). Polymorphisms were determined by polymerase chain reaction restriction length polymorphism. RESULTS: Thirty-three per cent of patients were positive for the T-786C polymorphism, 25% for the G894T polymorphism, and 18% carried mutated alleles in both loci. Maximal acetylcholine-induced ring relaxation was 46.7+/-3.2% in T-786C, 59.6+/-4.2% in G894T, and 66.7+/-7.4% in T-786C/G894T compared with 94.9+/-2.0% in wild-type subjects (P<0.05 versus T-786C, G894T, T-786C/G894T). Patients positive for an eNOS polymorphism with more than three cardiovascular risk factors displayed a further attenuation of acetylcholine-mediated relaxation (45+/-6 %) compared with having up to three risk factors (59+/-3%, P<0.05). CONCLUSION: In patients with CAD, in-vitro assessed endothelium-dependent relaxation of mammary arteries was significantly impaired in those positive for the T-786C or the G894T eNOS polymorphism. These results suggest that the presence of either one of the eNOS polymorphisms deteriorated endothelium-dependent vasodilatory capacity of large conduit vessels on top of classical risk factors in patients with CAD.     

Endothelial nitric oxide synthase gene polymorphism is associated with systemic lupus erythematosus

OBJECTIVE: In systemic lupus erythematosus (SLE), endothelial nitric oxide synthase (eNOS) gene locus has been found to be suggestive of linkage with disease, nitric oxide (NO) is produced in significant amounts, and endothelial cell dysfunction is observed. eNOS gene polymorphism may affect both the synthesis of eNOS protein and its enzymatic activity. We examined the influence of eNOS gene polymorphisms on susceptibility to SLE. METHODS: Genomic DNA from 88 Northwestern Colombian women with SLE, as well as 199 controls matched for sex, age, and ethnicity, was genotyped for the -786T -- > C polymorphism in the promoter region, the intron 4 variable number of tandem repeats, and the Glu298Asp polymorphism in exon 7 of the eNOS gene by polymerase chain reaction and restriction fragment length polymorphism techniques. Haplotype and allele frequency comparisons, a Hardy-Weinberg equilibrium test, and linkage disequilibrium (LD) analysis were performed. RESULTS: The intron 4b allele was associated with SLE (OR 2.2, 95% CI 1.29-3.60, pc = 0.005) as was the 4bb genotype (OR 2.9, 95% CI 1.61-5.33, pc = 0.0009), while the 4a allele was protective (OR 0.4, 95% CI 0.26-0.76, pc = 0.005), as was the 4ab genotype (OR 0.29, 95% CI 0.15-0.56, pc < 0.0001). In controls, all loci were in linkage disequilibrium (p < 0.02). In patients, intron 4 was in Hardy-Weinberg disequilibrium, due to an excess of homozygotes (p = 0.01). CONCLUSION: eNOS polymorphism influences SLE predisposition. Since intron 4bb genotype is responsible for higher levels of eNOS synthesis and intron 4 ab genotype is associated with lower synthesis, our results might provide insight into the elevated levels of NO observed in SLE patients.     

Association analyses between genetic polymorphisms of endothelial nitric oxide synthase gene and hypertension in Japanese: The Suita Study.

OBJECTIVES : Endothelium-derived nitric oxide plays a key role in the regulation of vascular tone. Recently, endothelial nitric oxide synthase (eNOS) gene polymorphisms were reported to be associated with hypertension or coronary spasm. We investigated the association between the eNOS gene polymorphisms and hypertension in a large population-based sample of 4055 Japanese. DESIGN AND METHODS : We investigated two polymorphisms of the eNOS gene, Glu298Asp polymorphism of exon 7 and T(-786)C polymorphism of the promoter region. The genotype distribution in hypertensive subjects was compared to that in the other subjects. The influence of the genotype on blood pressure values was analyzed in the subjects not taking hypertensive medication. The promoter activities of the eNOS gene with the (-786)T or (-786)C allele were measured by a luciferase reporter gene assay. RESULTS : There was significant linkage disequilibrium between the two polymorphisms (P < 0.0001). The genotype distribution of the Glu298Asp or T(-786)C polymorphism did not differ between the hypertensive and the other subjects. No significant differences in the blood pressure of subjects not taking hypertensive medication were observed among the three genotypes of Glu298Asp or T(-786)C polymorphisms. No significant differences in the promoter activity were observed between bovine endothelial cells transfected with the (-786)T and (-786)C alleles. CONCLUSIONS : Our data suggested that these polymorphisms of the eNOS gene are unlikely to be major factors in the susceptibility to hypertension in the Japanese population studied.     

Association analysis of endothelial nitric oxide synthase gene polymorphism with primary hypertension in a Singapore population

Vascular endothelial cells produce nitric oxide (NO), which contributes to the regulation of blood pressure and regional blood flow. Endothelial nitric oxide synthase (eNOS) gene polymorphisms are associated with coronary artery disease, but their linkage with primary hypertension is controversial. A total of 103 individuals with primary hypertension and 104 normotensive control subjects were studied in Singapore. The specific genotypes for G894T missense variant in exon 7, variable number tandem repeats (VNTR) in intron 4 (eNOS 4A/B/C) and T-786C in the promoter were isolated using allele-specific gene amplification and restriction fragment length polymorphism to examine the association of genotype and allelic frequency in both groups. Logistic regression analysis was also used to detect the association between genotypes and hypertension. Five genotypes of intron 4 VNTR (AA, AB, BB, AC and BC) were observed. Intron 4 B/B genotype was significantly associated with the hypertension group (P = 0.035), but disequilibrium of G894T and T-786C was absent between the two groups (P = 0.419 and P = 0.227), respectively. The overall distribution of allelic frequency differed significantly between the two groups, with four-repeat allele (4A) of intron 4 more frequent in the normotensive group than the hypertensive group (P = 0.019). Logistic regression analysis showed that intron 4 B/B genotype was significantly associated with systolic blood pressure of individuals with body mass index greater than 25 kg/m2 (P = 0.04). In conclusion, the eNOS 4 B/B genotype is a genetic susceptibility factor for primary hypertension in a Singapore population.     

内皮型一氧化氮合酶基因多态性与2型糖尿病及视网膜病变

采用PCR RFLP研究内皮型一氧化氮合酶 (eNOS)基因多态性与 2型糖尿病 (DM )及糖尿病视网膜病变 (DR)的关系。未发现eNOS基因的G894T及 4A/B多态性与 2型DM发生关联 ,eNOS基因 4A/B多态性与DR发生可能相关 ,eNOS基因的G894T多态性与DR发生可能无关。     

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。     

Endothelial nitric oxide synthase gene haplotype association with systemic lupus erythematosus

Endothelial nitric oxide synthase (eNOS) catalyses the production of nitric oxide, which has been shown to participate in the pathogenesis of systemic lupus erythematosus (SLE). eNOS gene polymorphism may have an effect on eNOS gene expression, eNOS protein synthesis and enzymatic activity. We investigated the influence of eNOS gene polymorphisms on susceptibility to SLE. eNOS T-786C, G894T and intron 4 27-base pair tandem repeat (VNTR4) polymorphisms were investigated in 152 SLE patients and 184 controls using RFLP-PCR, direct sequencing and fragment analysis. Allele, genotype and haplotype frequency comparisons, Hardy-Weinberg equilibrium and linkage disequilibrium (LD) analysis were performed. No significant association was detected between SLE and single-nucleotide polymorphisms (SNPs) T-786C and G894T. VNTR4 allele 4b was associated with susceptibility to SLE (OR 1.89, p?=?0.023), as was the genotype 4bb (OR 2.41, p?=?0.007). However, allele 4a was protective (OR 0.53, p?=?0.023), as was genotype 4ab (OR 0.41, p?=?0.007). T-786C and VNTR4 were in high LD (r (2?)=?0.34). Haplotypes T4bC and C4aG of the three tested polymorphisms had a susceptibility effect on SLE (OR 1.89 and 4.23 at p?=?0.005 and 0.001, respectively), while haplotypes T4aG and C4bG had a protective effect (OR 0.06 and 0.11 at p?=?0.000001 and 0.0005, respectively). The novel finding in our study is that individual eNOS polymorphisms probably do not exert a major influence on susceptibility to SLE, but they have significant effects when combined within a specific haplotype.     

The T-786C and Glu298Asp polymorphisms of the endothelial nitric oxide gene affect the forearm blood flow responses of Caucasian hypertensive patients

OBJECTIVES: We sought to investigate whether two polymorphisms located in the promoter (T(-786)C) and exon 7 (Glu298Asp) of the endothelial nitric oxide (NO) synthase (eNOS) gene affected agonists-mediated NO release. BACKGROUND: Endothelial dysfunction can be genetically determined. Therefore, we investigated whether two polymorphisms located in the eNOS gene affected agonists-mediated NO release. METHODS: We compared endothelial-dependent and -independent vasodilation of the different eNOS genotypes in a cross-sectional study on 187 subjects, of whom 137 were uncomplicated essential hypertensive patients (PH) (49 +/- 9 years, 151 +/- 11/99 +/- 5 mm Hg) and 50 healthy normotensive subjects (NT) (43 +/- 16 years, 123 +/- 10/78 +/- 7 mm Hg). Endothelial-dependent and -independent vasodilation was assessed as the forearm blood flow response to incrementally increasing doses of acetylcholine (0.15, 0.45, 1.5, 4.5, 15 microg/100 ml/min) and sodium nitroprusside (1, 2, 4 microg/100 ml/min), respectively. Genotyping was performed with melting curve analysis (Lightcycler) of polymerase chain reaction products from acceptor (5' end-labeled with LCRed 640) and donor probes (3' end-labeled with fluorescein) specific for each polymorphism.The genotype distribution of T(-786)C (CC = 21.9%, CT = 48.7%, TT = 29.4%) and Glu298Asp (GG = 39.0%, GT =51.9%, TT = 9.1%) was similar in PH and NT. A repeated measure analysis of variance showed a blunting of endothelium-dependent vasodilation in PH compared with NT (p < 0.001). A significant effect of the T(-786)C (p = 0.002) but not of the Glu298Asp (p = NS) eNOS polymorphism on endothelial-dependent vasodilation was found. However, we also detected a significant interaction between the T(-786)C and Glu298Asp polymorphism (p < 0.001). No effect on either polymorphism on endothelial-independent vasodilation was seen. CONCLUSIONS: The T(-786)C promoter polymorphism and its interaction with exon 7 Glu298Asp affect endothelium-dependent vasodilation in mild-to-moderate PH patients and NT Caucasian subjects.     

Endothelial nitric oxide synthase Glu298Asp, 4b/a, and T-786C polymorphisms in type 2 diabetic retinopathy

Objective The possible association between the endothelial nitric oxide (eNOS) gene T‐786C (promoter region), 27‐bp repeat 4b/4a (intron 4), and Glu298Asp (exon 7) polymorphisms with diabetic retinopathy (DR) was investigated. Design A retrospective case‐control study. Patients A total of 872 type 2 diabetes (T2DM) patients were studied, of whom 383 presented with preproliferative/proliferative retinopathy (DR group), and 489 with absent/mild retinopathy (DWR group). Measurements Glu298Asp and T‐786C genotyping was carried out by PCR‐RFLP analysis, while 4b/4a was assessed by PCR. Genotype distribution was compared using the χ²‐test, and the contributions of the polymorphisms to DR were analysed by haplotype analysis and multivariate regression analysis. Results Lower prevalence of mutant 4a (P = 0·011), and heterozygous 4b/4a (P = 0·042) were seen in the DR compared to the DWR groups; the allele and genotype distribution of the Glu298Asp and T‐786C polymorphisms were comparable between DR and DWR groups. Three‐loci haplotype analysis demonstrated significant association between eNOS variants and DR, with protective [haplotype 122 (Glu298/4a/‐786C)], and susceptible haplotypes [haplotypes 112 (Glu298/4b/‐786C) and 222 (Asp298/4a/‐786C)] identified. Multivariate regression analysis confirmed the association between haplotypes 122 (P = 0·015); 112 (P = 0·027), and 222 (P = 0·048) and DR, after controlling for potential covariates (including age, sex, age of disease onset; HbA1c; hypertension, total cholesterol). Conclusions This study identifies genetic variation at the eNOS locus as genetic risk factor for diabetic retinopathy, which may serve as a useful marker of increased susceptibility to the risk of retinopathy.     

Endothelial nitric oxide synthase haplotype associations in biopsy-proven giant cell arteritis

OBJECTIVE: To assess the influence of endothelial nitric oxide synthase (eNOS) polymorphisms in the susceptibility to giant cell arteritis (GCA). METHODS: We studied 57 patients with biopsy-proven GCA diagnosed at the Rheumatology Division of Hospital Xeral-Calde and 117 ethnically matched controls. Patients and controls were genotyped by PCR for a variable number tandem repeat polymorphism in intron 4, a T/C polymorphism at position -786 in the promoter region, and a polymorphism in exon 7 (298Glu/Asp or 5557G/T) of the eNOS gene. RESULTS: No differences in allele or genotype frequencies for individual polymorphisms were observed between patients with GCA and controls. However, when haplotype frequencies for the combination of the 3 eNOS polymorphisms were estimated, a significant increase in the frequency of haplotype C/1/T and a significant decrease in the frequency of haplotype C/1/G were observed in GCA patients compared to controls (p = 0.04, OR 1.8, 95% CI 1.0-3.3; p = 0.02, OR 0.3, 95% CI 0.1-0.8, respectively). CONCLUSION: Significant differences in eNOS haplotype frequencies between GCA patients and controls may indicate a role for these polymorphisms in the susceptibility to this condition.     

Endothelial nitric oxide synthase haplotypes affect the susceptibility to hypertension in patients with type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) and hypertension (HT) commonly coexist. While endothelial nitric oxide synthase (eNOS) haplotypes have been associated with HT, it is unknown whether eNOS genotypes/haplotypes are associated with altered susceptibility to HT in patients with T2DM. We studied the distribution of three eNOS genetic polymorphisms: a single nucleotide polymorphism in the promoter region (T(-786)C), in exon 7 (Glu298Asp), and a variable number of tandem repeats in intron 4(b/a). Genotypes were determined for 102 healthy controls, 119 patients with HT, 66 patients with T2DM, and 113 patients with T2DM+HT. In addition, we also compared the distribution of eNOS haplotypes in the four groups of subjects. No differences were found in genotype and allele distribution among the four groups. Conversely, the haplotypes "C Glu b" and "C Asp b" were, respectively, more and less common in healthy controls than in HT or in T2DM+HT groups (24% versus 6% and 5%, respectively; both P<0.00625; and 8% versus 18% and 18%, respectively; both P<0.00625). Moreover, DM patients presented an overall distribution of eNOS haplotypes that was not different from healthy controls (P>0.05). Additionally, the haplotypes "C Glu b" and "C Asp b" were, respectively, more and less common in T2DM group than in T2DM+HT group (19% versus 5%; and 7% versus 18%, respectively; both P<0.00625). Our findings suggest a protective effect for eNOS haplotype "C Glu b" against the development of hypertension, and that haplotype "C Asp b" increases the susceptibility to hypertension in patients without or with T2DM.     

Structure of the chromosomal gene for murine interleukin 3.

We have isolated the mouse interleukin 3 (IL-3) gene from a mouse sperm DNA library based on homology with the mouse mast-cell growth-factor (MCGF) cDNA sequence. The nucleotide sequence determined for the gene and its flanking regions reveals that the IL-3 gene is composed of four introns and five exons. The nucleotide sequence of the exons agrees with that determined for the MCGF cDNA. A "TATA"-like sequence preceded by a G + C-rich region is found in the 5' flanking region. At the 3' region of the second intron are nine repeats of a closely related 14-base-pair (bp) sequence. These repeated sequences share extensive homology with a 20-bp repeated sequence found in the human genome, which was shown to have enhancer activity. Eight out of nine repeats form a 73-bp duplicated sequence and each 73-bp repeat contains sequences homologous to the core sequence suggested for enhancer elements. These sequences may play a role in the expression of the IL-3 gene in concanavalin A- or antigen-stimulated T lymphocytes. Stable transformants of L cells generated by co-transformation of the IL-3 gene with pSV2neo constitutively express MCGF activity indicating that the isolated gene is functional in vivo.     

Susceptible and protective eNOS haplotypes in hypertensive black and white subjects

Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene have been inconsistently associated with hypertension. This inconsistency may derive from population stratification secondary to ethnic diversity, and consideration limited to only one rather than combinations of polymorphisms. We studied three genetic variations in the eNOS gene: 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) of the eNOS gene in hypertensives (112 whites and 91 blacks) and normotensives (113 whites and 87 blacks). In addition, we also examined the association of eNOS gene haplotypes with hypertension in white and black subjects. No differences were observed in the frequencies of genotypes and alleles of the three polymorphisms when white hypertensives and white normotensives were compared, or when black hypertensives and black normotensives were compared (all P>0.05). Conversely, the haplotypes "T Asp b" and "C Glu b" were more common among white (16 and 24%, respectively) and black (17 and 16%, respectively) normotensives than in white (7 and 8%, respectively) and black (4 and 6%, respectively) hypertensives, respectively (all P<0.0039). In addition, the haplotype "C Asp b" was more commonly found in white hypertensives than in white normotensives (P=0.0007). These results suggest a contribution of eNOS haplotypes to the development of hypertension that is obscured when specific eNOS genotypes alone are considered. In addition, our results suggest two eNOS haplotypes associated with a protective effect against hypertension in both ethnic groups, and one eNOS haplotype conferring susceptibility to hypertension in white subjects.