Lack of association between NOS2 pentanucleotide repeat polymorphism and asthma phenotypes or exhaled nitric oxide concentration

Nitric oxide (NO) plays an immunoregulatory role in balancing cellular immunity. The expression of inducible nitric oxide synthase gene (NOS2) is upregulated upon exposure to proinflammatory cytokines and microbial exposure. The (CCTTT)n polymorphism in NOS2 promoter confers protection against infections and immunological disorders including atopy. We investigated the association between (CCTTT)n and asthma traits in Chinese children. Asthmatic children between 5 and 18 years of age and non-allergic controls were recruited. Plasma total and specific IgEs were measured by immunoassays, and exhaled NO concentration was quantified online by chemiluminescence. NOS2 (CCTTT)n was genotyped by GeneScan analysis. The mean (SD) age of 291 asthmatics and 172 controls were 11.1 (3.8) years and 11.6 (4.0) years, respectively (P = 0.259). NOS2 (CCTTT)n followed Hardy-Weinberg equilibrium in both groups, and its uni-modal allele distribution peaks at 12-repeat. Significant interethnic differences in (CCTTT)n alleles were observed, with our Chinese having less 13-repeat (Pc = 0.022) but more 17-repeat (Pc = 0.033) than Caucasians. The frequency of 14-repeat allele was similar in our Chinese as compared to Japanese (Pc = 0.32). Multivariate regression analyses failed to detect any association between this polymorphic marker and asthma diagnosis (P = 0.949), atopy (P = 0.305), IgE sensitization to aeroallergens (P > 0.2 for all), or FeNO (P = 0.847). These findings do not support NOS2 to be a major candidate gene for asthma or IgE-mediated allergic diseases in Chinese children.     

Association of a functional inducible nitric oxide synthase promoter variant with susceptibility to biopsy-proven giant cell arteritis

OBJECTIVE: To assess the contribution of 2 polymorphisms within the inducible nitric oxide (NOS2A) promoter region to susceptibility to giant cell arteritis (GCA). METHODS: One hundred three patients with biopsy-proven GCA and 198 ethnically matched controls from the Lugo region (Northwest Spain) were studied. Patients and controls were genotyped using polymerase chain reaction techniques for a multiallelic (CCTTT)n and for the TAAA repeat polymorphism in the promoter region of the NOS2A gene. RESULTS: No significant differences in allele or genotype frequencies for the (CCTTT)n repeat polymorphism in the NOS2A gene between patients with GCA and controls were observed. However, significant differences for the TAAA repeat polymorphism between patients and controls were found. The overall distribution of NOS2A TAAA genotypes in patients with biopsy-proven GCA was significantly different than controls (p = 0.026). Patients with GCA had an increased frequency of the NOS2A TAAA+ allele (16.5%) compared with controls (9.1%) (p = 0.007; OR 1.98; 95% CI 1.20-3.27). This was due to an increased frequency of both heterozygotes (27.2%) and homozygotes (2.9%) for NOS2A TAAA+ observed in patients compared to controls (15.2% and 1.5%, respectively) (p = 0.007; OR 2.15; 95% CI 1.23-3.78). CONCLUSION: Our results suggest a potential implication for NOS2A TAAA gene polymorphism in GCA susceptibility.     

A polymorphism in the inducible nitric oxide synthase gene is associated with tuberculosis

iNOS or NOS2 is a molecule that plays a key role in the immunological control of a broad spectrum of infectious agents. Investigation is hampered by difficulty in estimating in vivo production of nitric oxide (NO), but genetic studies provide a potential means of examining the relation between NO production and disease outcome. To better characterize the host genetic factors determining the susceptibility to TB, we evaluated the influence of two polymorphisms in the NOS2A gene on the risk of developing pulmonary TB in a Northwestern Colombian population, which is a moderately-high endemic area. One hundred and fourteen patients with TB and negative for human immunodeficiency virus, plus 304 healthy controls were examined for NOS2A CCTTT and TAAA polymorphisms. A total of 160 healthy controls mentioned before, underwent tuberculin skin test (TST). Analysis disclosed significant differences between patients and controls with NOS2A CCTTT polymorphism (P=0.0001, Pc=0.001, OR=0.4, and 95%CI=0.3-0.7) independent of TST status. When the NOS2A alleles were stratified into short (8-11) and long (12-16) repeats, significant differences with short repeats were observed between TB patients and all controls (P=0.005, OR=0.63, 95%CI=0.46-0.86). No individual association with NOS2A TAAA was detected. These results indicate that a polymorphism in the NOS2A gene influences the susceptibility to TB and suggest a role for NOS2A in the pathogenesis of mycobacterial infection.     

Association of nitric oxide synthase gene polymorphism with asthma: A systematic review and meta-analysis

Introduction

This study examines the associations between asthma and nitric oxide (NO) synthase (NOS) gene polymorphisms.

Methods

After a systematic literature search in electronic databases, studies were selected based on eligibility criteria. Data were extracted from research articles and were synthesized and tabulated. Where a particular polymorphism data were reported by multiple studies, meta-analyses of odds ratios were performed, or odds ratios reported by individual studies were pooled.

Results

Twenty studies (4450 asthma patients and 5306 non-asthmatic individuals) were identified. Many studies did not find any association between CCTTT repeat polymorphism in NOS2 gene and asthma. However, a study reported that pretreatment mean exhaled NO levels in asthmatics were found to be significantly higher in genotypes with higher number of CCTTT repeats. Also, alleles with <11 CCTTT repeats were associated with poor asthma treatment outcomes. A single nucleotide polymorphism, G894T, in NOS3 gene was not found to be significantly associated with asthma by at least four studies. However, a T allele at this locus was associated with lower NO levels. Also, G894T frequency was significantly higher in asthmatic children who responded to inhaled corticosteroids along with long-lasting beta2-agonists. A T allele of NOS3 786C/T polymorphism increased the probability of bronchial asthma with comorbid essential hypertension in asthma patients. Asthma severity also differed for different Ser608Leu exon 16 variants of NOS2 gene.

Conclusions

Several polymorph NOS gene variants are identified, some of which appear to have influence on asthma prevalence or outcomes. However, data are varying depending on the nature of variant, ethnicity, study design, and disease parameters.     

Inducible nitric oxide synthase polymorphism is associated with susceptibility to Henoch-Schönlein purpura in northwestern Spain

OBJECTIVE: To assess the contribution of 2 polymorphisms within the inducible nitric oxide (NOS2A) promoter region to the susceptibility to Henoch-Sch?nlein purpura (HSP), and to determine if implications exist with severe systemic complications of HSP, in particular with severe renal involvement and permanent renal dysfunction (renal sequelae). METHODS: Fifty-eight patients from Northwest Spain with primary cutaneous vasculitis classified as HSP were studied. All patients were required to have had at least 2 years' followup. Patients and ethnically matched controls (n=251) were genotyped by PCR based techniques for a multiallelic (CCTTT)n and for the biallelic TAAA repeat in the promoter region of the NOS2A gene. RESULTS: HSP patients exhibited a significantly increased frequency of the NOS2A short (8-11) CCTTTn alleles (OR 1.64, 95% CI 1.09-2.47, p=0.017) and genotypes (OR 3.59, 95% CI 1.79-7.20, p=0.0002) compared to controls, particularly when patients with nephritis were compared with controls. However, when the NOS2A TAAA repeat polymorphism was assessed, no differences were found. CONCLUSION: Significant differences in the NOS2A promoter polymorphism allele and genotype frequency between HSP patients and controls suggest a potential role for this gene in the susceptibility to HSP and in the development of nephritis.     

Polymorphisms in oxidative pathway related genes and susceptibility to inflammatory bowel disease

AIM To investigate whether common variants in the oxidative pathway genes influence inflammatory bowel disease(IBD) risk among Moroccan patients. METHODS The distribution of(TAAA)n_rs12720460 and(CCTTT)n_rs3833912 NOS2 A microsatellite repeats, HIF-1 A_rs11549467 and NFKB1-94 ins/delA TTG_rs28362491 was analyzed in 507 subjects grouped in 199 IBD and 308 healthy controls. Genotyping was performed withpolymerase chain reaction-fluorescent method and the TaqMan~? allelic discrimination technology.RESULTS The allele and genotype frequencies of HIF1 A_ rs11549467, NFKB1_rs28362491 and NOS2 A_(TAAA)n did not differ significantly between patients and controls. Analysis of NOS2 A_(CCTTT)n markers evidenced differences between patients and healthy controls. A preferential presence of the(CCTTT)8(P = 0.02; OR = 1.71, 95%CI: 1.07-2.74),(CCTTT)14(P = 0.02; OR = 1.71, 95%CI: 1.06-2.76) alleles in IBD,(CCTTT)8(P = 0.008; OR = 1.95, 95%CI: 1.17-3.23) in CD and(CCTTT)7(P = 0.009; OR = 7.61, 95%CI: 1.25-46.08),(CCTTT)11(P = 0.05; OR = 0.51, 95%CI: 0.25-1.01),(CCTTT)14(P = 0.02; OR = 2.05, 95%CI: 1.07-3.94),(CCTTT)15(P = 0.01; OR = 2.25, 95%CI: 1.16-4.35) repeats in UC patients indicated its possible association with higher disease risk which need to be confirmed in a larger sample size. CONCLUSION Our results suggest that the NOS2 A_(CCTTT)n gene variations may influence IBD susceptibility in the Moroccan population.     

Inducible but not endothelial nitric oxide synthase polymorphism is associated with susceptibility to rheumatoid arthritis in northwest Spain

OBJECTIVE: To assess the influence of inducible and endothelial nitric oxide synthase (iNOS and eNOS) polymorphisms in susceptibility to rheumatoid arthritis (RA). METHODS: Two hundred RA patients fulfilling the 1987 American College of Rheumatology classification criteria followed at the out-patient rheumatology clinic of the Hospital Xeral-Calde (Lugo, Spain) and 251 ethnically matched controls were studied. Patients and controls were genotyped by PCR-based techniques for a multiallelic (CCTTT)(n) repeat in the promoter region of the iNOS gene and for 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 significant difference in allele or genotype frequencies for either polymorphism in the eNOS gene was observed between RA patients and controls. The overall iNOS CCTTT(n) allelic or genotypic distribution did not show statistical significant differences between RA patients and controls. Interestingly, when we stratified the iNOS alleles into short (8-11) and long (12-16) repeats, significant differences were observed between RA patients and controls (P = 0.021; odds ratio = 1.37, 95% confidence interval 1.04-1.81). Of note, individuals carrying two alleles with a repeat number less than 12 (fewer than 196 base pairs) exhibited a double risk of developing RA (P = 0.005, odds ratio 2.26, 95% confidence interval 1.25-4.08). CONCLUSIONS: Significant differences in the iNOS promoter polymorphism genotype frequency between northwest Spanish RA patients and controls suggest a potential role for this polymorphism in susceptibility to RA.     

Inducible nitric oxide synthase gene promoter polymorphism is associated with increased gastric mRNA expression of inducible nitric oxide synthase and increased risk of gastric carcinoma

BACKGROUND AND AIMS: Stimulation of inducible nitric oxide synthase gene expression by Helicobacter pylori, with subsequent overproduction of nitric oxide, has been implicated in gastric carcinogenesis. We investigated whether inducible nitric oxide synthase promoter gene polymorphisms are associated with (a) inducible nitric oxide synthase mRNA expression in the gastric mucosa, and (b) the risk of gastric carcinoma. MATERIALS AND METHODS: The relationship between gastric inducible nitric oxide synthase mRNA expression and inducible nitric oxide synthase promoter polymorphisms (CCTTT repeat polymorphism and -2445 C-->G SNP) was examined in 74 H. pylori-infected patients with gastric cancer, peptic ulcer, or functional dyspepsia. In a case-control study the prevalence of the polymorphisms was examined in H. pylori-infected gastric carcinomas (n=77) and noncancerous controls (n=154). RESULTS: Inducible nitric oxide synthase mRNA levels were significantly higher in long CCTTT repeat (either allele>11) carriers than in short ones (P=0.015). Multivariate regression analysis showed that inducible nitric oxide synthase mRNA expression was significantly linked to long CCTTT repeat and gastric cancer (P=0.026), but not to -2445 C-->G SNP and other parameters. The case-control study showed that long CCTTT repeat carriers had an increased risk of gastric cancer with an odds ratio of 2.0 (P=0.021). -2445 C-->G SNP was not associated with the risk. CONCLUSIONS: Helicobacter pylori induces higher inducible nitric oxide synthase mRNA expression in carriers of long CCTTT repeats of inducible nitric oxide synthase promoter, and this polymorphism is associated with an increased risk of gastric carcinoma.     

Association of -238G／A polymorphism of tumor necrosis factor-alpha gene promoter region with outcomes of hepatitis B virus infection in Chinese Han population

AIM: To clarify whether -238G/A polymorphism of tumor necrosis factor-a (TNF-a) gene promoter region was associated with outcomes of hepatitis B virus (HBV) infection in Han population of northern China, and to analyze the geneenvironment interaction between -238G/A polymorphism and cigarette smoking or alcohol consumption. METHODS: A case-control study was conducted to analyze the association of TNF-a gene promoter polymorphism with HBV infection outcomes. A total of 207 patients with chronic hepatitis B (HB) and 148 cases of self-limited HBV infection from Ditan Hospital and Shunyi District Hospital in Beijing, respectively were recruited. History of smoking and alcohol drinking was inquired by a questionnaire. The -238G/A polymorphism of TNF-a gene promoter was genotyped by polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP). RESULTS: The frequencies of GG and GA genotypes were 98.07% and 1.93% in chronic HB patients and 93.24% and 6.76% in self-limited HBV infection individuals, respectively (X^2=5.30, P=-0.02). The frequency of G allele was significantly higher in patients with chronic HB that in individuals with self-limited HBV infection (99.03% vs 96.62%, X^2=5.20, P=0.02). Only modestly increased risk of onset of chronic HB was found in smokers (OR=1.40, 95% CI： 0.87-2.28, P=0.14) and drinkers (OR=-1.26, 95%CI： 0.78-2.05, P=-0.32). There was a positive interaction between genotype GG and cigarette smoking with an interaction index (Ⅱ) of 2.95, or alcohol consumption with an Ⅱ of 1.64. CONCLUSION: The -238G/A polymorphism of TNF-a gene promoter region is independently associated with different outcomes of HBV infection.     

Estudio de la repetición del pentanucleótido CCTTT en el gen de la sintasa inducible del óxido nítrico en pacientes con hipertensión arterial pulmonar

Introduction

One of the pathways involved in pulmonary arterial hypertension (PAH) is the nitric oxide (NO) pathway. A polymorphism in the inducible NO synthase (NOS2) gene has been described, consisting of the CCTTT pentanucleotide repeat, which causes a reduction in NO production. The aim of this study was to determine if this polymorphism increases susceptibility to developing PAH.

Methods

Sixty four patients with a diagnosis of PAH groups i and iv and 50 healthy controls were compared. DNA genotyping of the samples for this polymorphism was performed using PCR. The distribution between both groups was compared and correlated with clinical and haemodynamic parameters and therapeutic response.

Results

A significantly different distribution was observed in the number of repeats between patients and controls (P < .0001). When the samples were categorised by short forms (both alleles with less than 12 repeats) and long forms (≥ 12 repeats), it was observed that the former had an almost 4-fold risk of developing PAH (odds ratio: 3.83; 95% CI: 1.19-12.32, P = .024). There were no differences between the most common types of PAH, either in therapeutic response or survival. There was no correlation between haemodynamic parameters and the number of repeats in the patients, and only a weak correlation with systolic PAH.

Conclusions

There are significant differences in the distribution of the NOS2 promotor CCTTT polymorphism between patients with PAH and the healthy population. A minor CCTTT pentanucleotide repeat in the NOS2 gene may increase the risk of developing PAH.     

Polymorphisms in the endothelial nitric oxide synthase gene are associated with Behçet's disease

OBJECTIVE: Reduced plasma nitric oxide (NO) levels in Beh?et's disease (BD) patients have been implicated in the development of the endothelial abnormalities and thrombotic complications occurring in these patients. This study investigated the association of the endothelial NO Synthase (eNOS) gene polymorphisms with BD. METHODS: A case-control study was carried out using 193 unrelated Turkish BD patients and 106 healthy controls. All individuals were genotyped by PCR for two single-nucleotide polymorphisms (SNPs): -786 T-->C in the promoter region and 894 G-->T in exon 7 (Glu298Asp). A variable number of tandem repeats (VNTR) polymorphism in intron 4 was also investigated. RESULTS: The VNTR polymorphism was associated with BD, detected by an increased frequency of the b allele (odds ratio = 1.9, P = 0.0069) and b/b genotype (odds ratio = 2.2, P = 0.002) in patients. After the stratification of cases according to the family history, a significant difference between familial cases and controls in the -786 SNP was observed, with an increase in the frequency of the T allele (odds ratio = 2.5, P = 0.0016) and T/T genotype (odds ratio = 2.5, P = 0.0085), and the association of the VNTR polymorphism with BD became stronger. The -786*T and VNTR*b alleles were in linkage disequilibrium (D' = 0.65, P <0.0001), and the number of individuals homozygous for the -786*T/VNTR*b haplotype was significantly increased in the patients. CONCLUSIONS: eNOS gene polymorphisms are associated with BD, which might contribute to the reduced NO activity observed in BD patients.     

Nitric oxide synthase gene polymorphisms and nephropathy in Asians with Type 2 diabetes

OBJECTIVE: Recent studies on Caucasians have reported an association between diabetic microvascular complications and polymorphisms in the inducible nitric oxide synthase (iNOS) gene. In view of the differences in the pattern of diabetic complications in Asians, we studied these iNOS polymorphisms in Asians with Type 2 diabetes who do and those who do not have nephropathy. METHODS: Two hundred fifty-eight Asians who have had Type 2 diabetes for at least 10 years, with overt nephropathy or with normoalbuminuria, were genotyped for the (AAAT)(n) and (CCTTT)(n) polymorphisms in the promoter region of the iNOS gene. A subanalysis was made of the findings from the three ethnic groups (Chinese, Malays, and Indians). RESULTS: The (AAAT)(3) polymorphism, which is the most common allele in Caucasians, was completely absent in our entire cohort of 258 Asian diabetics. The (AAAT)(4) polymorphism was the commonest, with a frequency of 0.984 as compared with 0.2 in Caucasians. We also found previously unreported alleles: (AAAT)(5) in 6 patients and (AAAT)(6) in 1 patient. There was no statistically significant association with nephropathy, in view of the highly skewed distribution of the alleles. However, the higher repeats (AAAT)(5) and (AAAT)(6) were found in the patients with a very rapid onset of severe nephropathy. The (CCTTT)(n) polymorphism also showed significant differences in allele distribution between the Asian and the Caucasian and African populations (P=.001). However, there was also no significant association with nephropathy and no significant difference in the ethnic distribution of alleles. CONCLUSIONS: We have identified significant differences in the (AAAT)(n) and (CCTTT)(n) polymorphisms in Asian diabetics. We have shown that there are significant differences in the overall allele distribution between the Asian and the Caucasian and African populations. However, our study did not demonstrate an association between iNOS gene polymorphisms and diabetic nephropathy.     

Physician-diagnosed asthma and acute chest syndrome: associations with NOS polymorphisms

The main objectives of this paper were to test the hypothesis that polymorphisms in NOS1 and NOS3 genes associate with ACS in SCD patients and to characterize the association between physician-diagnosed asthma and acute chest syndrome (ACS). Case-control study of sickle cell disease patients >or=5 years old with ACS (cases; n=86) and those without ACS (controls; n=48) was carried out. Associations between ACS and the AAT repeat in intron 13 (formerly intron 20) of the NOS1, and with NOS3 T-786C polymorphism were explored. Physician-diagnosed asthma was determined by chart review, patient- or parent (guardian)-reported asthma, and drug use. Eighty five percent of participants with asthma had at least one episode of ACS compared to 14.6% of controls: adjusted odds ratio (OR) (95%CI) 5.46 (2.20,13.5), P= or<0.0001. Asthma correlated with the number of episodes of ACS (P<0.001). NOS1 AAT repeat polymorphism associated with the risk of ACS (P=0.001) in patients without physician-diagnosed asthma. No associations were found between the genotype of the NOS3 T-786C SNP and ACS. Physician-diagnosed asthma is a major risk factor for ACS. NOS1 AAT repeat polymorphism may contribute to physician-diagnosed asthma.     

Nasal nitric oxide concentration in paranasal sinus inflammatory diseases.

In normal upper airways, nitric oxide is generated by the paranasal sinus epithelium and then diffuses into the nasal cavities. This study examined whether or not nasal NO concentration is affected by paranasal sinus inflammatory diseases. The influence of obstruction (nasal polyposis) and/or inflammation (allergy or chronic sinusitis) of the paranasal sinuses on nasal NO concentration was evaluated in nasal allergic (n=7 patients) or nonallergic (n=20) polyposis, nonallergic chronic sinusitis (n=10) and Kartagener's syndrome (n=6) and compared with control subjects (n=42). A score of alteration of the paranasal sinus (number of altered and occluded sinuses) was determined by a computed tomography scan. The nasal NO concentration in nasal nonallergic polyposis (150+/-20 parts per billion (ppb)) was significantly decreased compared with both controls (223+/-6 ppb, p=0.01) and polyposis with allergy (272+/-28 ppb, p<0.0001). In each group, the nasal NO concentration was inversely correlated with the extent of tomodensitometric alteration of the paranasal sinuses. In Kartagener's syndrome, the nasal NO concentration (14+/-2 ppb) was drastically decreased compared with all other groups, despite the presence of open paranasal sinuses. Thus, the nasal NO concentration in patients with nasal polyposis appeared to be dependent on both the allergic status and the degree of obstruction of the paranasal sinuses.     

Lack of evidence for contribution of intron4a/b polymorphism of endothelial nitric oxide synthase (NOS3) gene to plasma nitric oxide levels

OBJECTIVE: Nitric oxide (NO) is synthesized from L-arginine by endothelium nitric oxide synthase (NOS3). It has been shown that reduced NO synthesis in endothelial cells has been implicated in the development of coronary atherosclerosis. We hypothesized that polymorphisms of NOS3 gene might be associated with increased susceptibility of coronary artery disease (CAD) and plasma NO concentrations. METHODS AND RESULTS: We studied the NOS3 intron4 gene polymorphism in 141 unrelated CAD patients with positive coronary angiograms in the Shahid Rajaee Heart Hospital and 159 age-matched control subjects without a history of symptomatic CAD. The NOS3 gene polymorphism was analysed by polymerase chain reaction. Plasma NO was also determined. The genotype frequencies for NOS34a/b polymorphism differed significantly between CAD patients and controls (P = 0.041). Mean plasma NOx concentration was significantly higher (P = 0.0009) in CAD patients (87.5 microM) than in controls (62.7 microM). Mean plasma NOx concentrations in the subjects with 4a allele and in the subjects without 4a allele were not significantly different. Plasma lipids, except HDL-C were also remarkably increased in the CAD group. CONCLUSIONS: The present study provides evidence that the intron4a/b polymorphism of the NOS3 gene is associated with CAD. Mean plasma NO was higher in CAD patients than in control subjects. The NOS34a/b polymorphism was not associated with increased plasma NO.