Endothelial nitric oxide synthase gene polymorphisms in Behçet's disease and rheumatic diseases with vasculitis

Endothelıal nıtrıc oxide synthase Glu298asp gene polymorphism in the cases of idiopathic thrombocytopenic purpura

Background

Nitric oxide (NO) can induce apoptosis in megakaryocytes. Stimulatory function of NO on platelet production may be important in the pathophysiology of idiopathic thrombocytopenic purpura (ITP). NO is produced by three isoforms of NO synthase (NOS). The endothelial nitric oxide synthase (eNOS) isoform has been detected in platelets. Polymorphism of the eNOS gene, which supplies NO synthesis, changes the functions of this enzyme. In this study, the role of eNOS Glu298Asp gene polymorphism in etiopathogenesis, its course, and treatment of ITP was investigated.

Methods

Sixty-six patients [51 newly diagnosed ITP (ND-ITP), 15 chronic ITP (CH-ITP), and 60 healthy controls (HC)] were enrolled in this study.

Results

In all patients, the frequency of the GT genotype was 48.5%. The frequency of the GG genotype was determined to be 40.9% and the TT genotype was 10.6%. The most common allele in all patients was the G allele. eNOS Glu298Asp gene polymorphism might be a risk factor in the etiopathogenesis of ITP. Patients with the GG genotype were thought to have a high intention for CH-ITP. Patients with the GG genotype responded effectively to medical treatment using IVIG therapy. The presence of the G allele was observed to have a positive effect on the medical treatment of patients with CH-ITP, whereas the T allele exhibited a negative effect.

Conclusion

In the present study, a significant correlation was found between ITP and eNOS Glu298Asp gene polymorphism. This correlation suggested that eNOS Glu298Asp gene polymorphism might be a risk factor in the ethiopathogenesis of ITP.

A comprehensive overview on the genetics of Behçet's disease

Behçet's disease (BD) is a systemic and inflammatory disease, characterized mainly by recurrent oral and genital ulcers, eye involvement, and skin lesions. Although the exact etiopathogenesis of BD remains unrevealed, a bulk of studies have implicated the genetic contributing factors as critical players in disease predisposition. In countries along the Silk Road, human leukocyte antigen (HLA)-B51 has been reported as the strongest genetically associated factor for BD. Genome-wide association studies, local genetic polymorphism studies, and meta-analysis of combined data from Turkish, Iranian, and Japanese populations have also identified new genetic associations with BD. Among these, other HLA alleles such as HLA-B*15, HLA-B*27, HLA-B*57, and HLA-A*26 have been found as independent risk factors for BD, whereas HLA-B*49 and HLA-A*03 are independent protective alleles for BD. Moreover, other genes have also reached the genome-wide significance level of association with BD susceptibility, including IL10, IL23R-IL12RB2, IL12A, CCR1-CCR3, STAT4, TNFAIP3, ERAP1, KLRC4, and FUT2. Also, several rare nonsynonymous variants in TLR4, IL23R, NOD2, and MEFV genes have been reported to be involved in BD pathogenesis. According to genetic determinants in the loci outside the MHC region that are contributed to the host defense, immunity, and inflammation pathways, it is suggested that immune responses to the pathogen as an important environmental factor and mucosal immunity contribute to BD susceptibility.

Association of endothelial nitric oxide synthase (eNOS) and norepinephrine transporter (NET) genes polymorphism with type 2 diabetes mellitus

Genetic factors in combination with environmental factors play a critical role in the development type 2 diabetes mellitus (T2DM) which is growing as an epidemic globally. In present study we aim to assess the association of eNOS (G894T, rs1799983) and NET (G1287A, rs5569) genes polymorphism with T2DM. A case-control study including a total of 400 North Indian subjects (200 T2DM cases and 200 controls) was performed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) approach to analyze genetic polymorphism. Alleles/genotype frequencies between cases and controls were compared using χ² and Student's t-tests. Odds ratios and 95% confidence intervals were calculated by logistic regression to assess the relative association between disease and genotypes. In case of NET gene, GG (P = 0.002 in T2DM males, 0.053 in overall T2DM cases) genotype and G allele (P = 0.003 in T2DM males, 0.027 in overall T2DM cases) were found to be a positive risk factors and AG genotype (P = 0.012 in T2DM males) and A allele (P = 0.003 in T2DM males, P = 0.027 in overall T2DM cases) as negative risk factor for T2DM. No association of eNOS gene polymorphism was found with T2DM (P values of all genotypes and alleles were greater than 0.05). NET gene polymorphism might be associated with the risk of T2DM whereas; eNOS gene polymorphism do not confer any risk of T2DM in North Indian Ethnic group. It is hoped that understanding genetic causes of T2DM will lead to earlier diagnosis, preventive measures and more effective and specific treatment.

Relationship of genetic factors with development of aortic dissection and aneurysm

Background

This study aims to investigate the relationship between the development of aortic dissections and aneurysms with the polymorphisms of angiotensin converting enzyme gene, methylenetetrahydrofolate reductase gene, plasminogen activator inhibitor-1 gene, and nitric oxide synthase gene.

Methods

Between April 2009 and July 2014, 38 patients with aortic dissections (28 males, 10 females; mean age 55.1±10.7 years; range, 30 to 78 years) and 67 patients with aortic aneurysms (57 males, 10 females; mean age 63.0±11.4 years; range, 31 to 82 years) were included in this cross-sectional study. The control group consisted of 60 healthy volunteers (41 males, 19 females; mean age 56.3±11.2 years; range, 30 to 82 years) without an aortic aneurysm or dissection, as assessed by thoracoabdominal computed tomography. The prespecified four genes were genotyped with competitive allelespecific polymerase chain reaction.

Results

The aortic dissection group had higher nitric oxide synthase-3 (4b/4b) expression levels, compared to the control group. The aortic aneurysm group had also higher nitric oxide synthase-3 (4b/4a) expression levels, compared to the control group. Compared to the control group, a higher rate of angiotensin converting enzyme I/D gene polymorphism was detected in the aneurysm group, while higher D/D polymorphism rates were found in the dissection group; although not statistically significant.

Conclusion

Our study results suggest that the nitric oxide synthase-3 intron 4b/4b and nitric oxide synthase-3 intron 4b/4a gene polymorphisms can be used as a predictor of aortic dissection and aneurysm development.

Association of a NOS3 gene polymorphism with Behçet's disease but not with Vogt-Koyanagi-Harada syndrome in Han Chinese

PURPOSE

Previous studies have identified that nitric oxide synthase (NOS) genes are associated with several immune-mediated diseases. This study aimed to investigate whether NOS2 and NOS3 gene polymorphisms are associated with Behçet's disease (BD) and Vogt-Koyanagi-Harada (VKH) syndrome in a Han Chinese population.

METHODS

An association analysis of NOS2/rs4795067, NOS3/rs1799983 and NOS3/rs1800779 was performed in 733 patients with BD, 800 patients with VKH syndrome, and 1,359 controls using PCR restriction fragment length polymorphism (PCR-RFLP) assay. Statistical analysis was performed with the chi-square test followed by the Bonferroni correction.

RESULTS

The result showed a decreased frequency of the NOS3/rs1799983 GG genotype and an increased frequency of NOS3/rs1799983 GT genotype in the patients with BD (Bonferroni correction test [Pc]=0.02, odds ratio [OR]=0.74; Pc=2.1×10(-3), OR=1.57, respectively). No significant association was found between rs1799983 and VKH syndrome. NOS2/ rs4795067 and NOS3/rs1800779 were not associated with either BD or VKH syndrome.

CONCLUSIONS

Our findings suggest that a NOS3/rs1799983polymorphism is associated with susceptibility to BD in Han Chinese.

Molecular Genetic Advances in Uveitis

Uveitis is usually considered as an intraocular inflammation characterized by variety of clinical features. Behcet's disease (BD), Vogt-Koyanagi-Harada (VKH) syndrome, acute anterior uveitis (AAU), and birdshot chorioretinopathy (BCR) are examples of noninfectious forms of uveitis. Although the precise pathogenesis remains unclear, accumulating evidence shows that complex genetic backgrounds coupled with an aberrant immune response may be implicated in the development of uveitis. The complement and pattern recognition systems are both important factors of the innate immune system and are involved in the pathogenesis of uveitis. Copy number variants (CNVs) of complement component 4 have been found to be associated with BD and VKH syndrome, but not with AAU. Several CNVs and gene polymorphisms of toll-like receptors were found to be associated with BD. Leukocytes are an important part of the adaptive immune system and various molecules on these cells play an important role in the development of uveitis. Genes encoding for human leukocyte antigens (HLAs) have been shown to be associated with certain uveitis entities, including BD (HLA-B51), VKH syndrome (HLA-DR4, DRB1/DQA1), AAU (HLA-B27), and BCR (HLA-A29). Genome wide association studies showed that the IL-23R locus was a shared risk factor for multiple uveitis entities including BD, AAU, and VKH syndrome. In addition, various other non-HLA genes are also associated with BD or VKH syndrome, such as IL-10, STAT4, STAT3, and UBAC2. These studies support the hypothesis that genetic factors play a key role in the pathogenesis of uveitis.

Etiopathogenesis of recurrent aphthous stomatitis and the role of immunologic aspects: literature review

Recurrent aphthous stomatitis (RAS; recurrent aphthous ulcers; canker sores) belongs to the group of chronic, inflammatory, ulcerative diseases of the oral mucosa. Up to now, the etiopathogenesis of this condition remains unclear; it is, however, considered to be multifactorial. The results of currently performed studies indicate that genetically mediated disturbances of the innate and acquired immunity play an important role in the disease development. Factors that modify the immunologic response in RAS include: food allergies, vitamin and microelement deficiencies, hormonal and gastrointestinal disorders (e.g., celiac disease, Crohn’s disease, ulcerative colitis), some viral and bacterial infections, mechanical injuries and stress. In this paper, we presented the main etiopathogenetic factors of RAS with a special emphasis on the mechanisms of the immune response modification. Moreover, we discussed the crucial clinical symptoms and types of RAS together with epidemiologic data based on the current medical literature reports and our own observations.

Role of nitric oxide synthase genes in hepatitis E virus infection

Hepatitis E virus (HEV) is the most common cause of endemic and epidemic acute hepatitis. A correlation between iNOS, eNOS polymorphisms, levels and severity of disease has been reported, and here, we examined the role of iNOS and eNOS gene polymorphisms and their levels in HEV-related acute viral hepatitis and acute liver failure. Hepatitis E virus-related cases of acute hepatitis (294 patients) and liver failure (82 patients) and age- and sex-matched healthy controls (331 subjects) were included in the study. PCR-RFLP was performed to identify the polymorphisms in the iNOS and eNOS genes. iNOS and eNOS levels were studied using ELISA assays and HEV viral load, genotype and combined effects of iNOS genotype, levels and parameters for disease severity were examined. The frequency of iNOS (CT + TT) and eNOS (GT + TT) genotypes was higher in subjects with liver failure compared with controls. iNOS and eNOS levels in patients with acute liver failure (55.51 ± 6.33 IU/mL, 60.2 ± 3.69) cases were significantly increased as compared to patients with acute viral hepatitis (17.8 ± 6.08 IU/mL, 23.7 ± 6.57) and controls (P < 0.05). A significant positive correlation was observed between the iNOS and eNOS levels in our study population when compared with the severity of disease parameters. Hence, the iNOS C150T polymorphism and the eNOS G894T polymorphism and high levels of iNOS and eNOS are associated with an increased risk of HEV-related acute hepatitis and liver failure. This study supports the possible role of nitric oxide synthase genes (iNOS and eNOS) in determining the severity of HEV infection.

Recurrent aphthous stomatitis: genetic aspects of etiology

Recurrent aphthous stomatitis (RAS; recurrent aphthous ulcers - RAU; canker sores) is a chronic inflammatory, ulcerative condition of the oral mucosa. Its prevalence in the general population ranges between 5% and 20%, depending on the method and group studied. The etiopathogenesis of the disease is considered to be multifactorial, but remains still not fully understood. In patients with RAS, an enhanced immunologic response occurs to some trigger factors that may include: mechanical injury, stress or bacterial and viral antigens. Higher prevalence of aphthae in relatives may also indicate the genetic background of the condition. The inheritance of some specific gene polymorphisms, especially those encoding proinflammatory cytokines, which play a role in the formation of aphthous ulcer, may predispose family members to RAS. The purpose of this paper was to present the main clinical features of recurrent aphthous stomatitis, epidemiologic data and crucial etiopathogenetic factors with a special emphasis on genetic background of the condition.

Identification of a susceptibility locus in STAT4 for Behçet's disease in Han Chinese in a genome-wide association study

OBJECTIVE

To identify susceptibility loci for Behçet's disease (BD) and elucidate their functional role.

METHODS

A genome-wide association study (GWAS) and functional studies were conducted. A total of 149 patients and 951 controls were enrolled in the initial GWAS, and 554 patients and 1,159 controls were enrolled in the replication study. Real-time polymerase chain reaction, luciferase reporter assay, and enzyme-linked immunosorbent assay were performed.

RESULTS

Our GWAS and replication studies identified a susceptibility locus around STAT4 (single-nucleotide polymorphisms [SNPs] rs7574070, rs7572482, and rs897200; P = 3.36 × 10(-7) to 6.20 × 10(-9) ). Increased expression of STAT4 was observed in individuals carrying the rs897200 risk genotype AA. Consistent with the idea that STAT4 regulates the production of interleukin-17 (IL-17) and interferon-γ, IL17 messenger RNA and protein levels were increased in individuals carrying the rs897200 risk genotype AA. Interestingly, the risk allele A of rs897200 creates a putative transcription factor binding site. To test whether it directly affects STAT4 transcription, an in vitro luciferase reporter gene assay was performed. Higher transcription activity was observed in individuals carrying the risk allele A, suggesting that rs897200 is likely to directly affect STAT4 expression. Additionally, 2 SNPs, rs7574070 and rs7572482, which are tightly linked with rs897200, were cis-expression quantitative trait loci (eQTL) SNPs, suggesting that SNP rs897200 is an eQTL SNP. Most importantly, the clinical disease severity score was higher in individuals with the rs897200 risk genotype AA.

CONCLUSION

These findings strongly suggest that STAT4 is a novel locus underlying BD. We propose a model in which up-regulation of STAT4 expression and subsequent STAT4-driven production of inflammatory cytokines, such as IL-17, constitute a potential pathway leading to BD.

Replication study confirms the association between UBAC2 and Behçet's disease in two independent Chinese sets of patients and controls

Introduction

The purpose of this study was to replicate genetic factors associated with the susceptibility to Behçet's disease (BD). We conducted a two-stage candidate genes association and functional study, involving 477 BD patients and 1,334 normal controls of Chinese Han descent.

Methods

The genotyping of five candidate genes/loci, including LOC100129342, KIAA1529, CPVL, UBASH3B and UBAC2, were performed using TaqMan single nucleotide polymorphism (SNP) assays. Real-time PCR and luciferase reporter assay were performed to test the function of the identified promoter polymorphism. The main outcome measures were genotype frequencies and expression levels in BD patients.

Results

The first-stage study results showed that UBAC2 (rs9513584, Pc = 0.018, OR = 1.4), but not LOC100129342, KIAA1529, CPVL, UBASH3B was associated with the susceptibility to BD in Chinese Han. The fine-mapping association study of UBAC2 identified six risk SNPs for BD in the Chinese cohort; three of them were verified in validation study (rs3825427, first-stage Pc = 2.2 × 10^-3, second-stage Pc = 9.3 × 10^-3, combined Pc = 6.9 × 10^-6; rs9517668, first-stage Pc = 1.7 × 10^-3, second-stage Pc = 0.03, combined Pc = 3.3 × 10^-4; rs9517701, first-stage Pc = 5.1 × 10^-3, second-stage Pc = 9.0 × 10^-3, combined Pc = 2.9 × 10^-5; respectively). Functional analysis showed that the risk T allele of the promoter polymorphism rs3825427 had a significantly lower promoter activity than the non-risk G allele (P = 0.002) and a decreased expression of UBAC2 transcript variant 1 in peripheral blood mononuclear cells (PBMCs) and skin of normal controls carrying the risk T allele than that in individuals with the G allele (P = 0.045, P = 0.025; respectively). The mRNA expression of UBAC2 transcript variant 1 was significantly decreased in PBMCs and skin of BD patients as compared with controls (P = 0.025; P = 0.047, respectively). The mRNA expression of UBAC2 transcript variant 2 was significantly increased in skin of BD patients as compared with controls (P = 0.004).

Conclusions

This study replicates a predisposition gene to BD, UBAC2, and suggests that UBAC2 may be involved in the development of BD through its transcriptional modulation.

Ocular Behçet disease: current therapeutic approaches

PURPOSE OF REVIEW

To alert physician to timely recognition and current treatment of recurrent hypopyon iridocyclitis or panuveitis in ocular Behçet disease (OBD).

RECENT FINDINGS

Interferon-α, rituximab, intravitreal triamcinolone, and biological response modifiers by tumor necrosis factor inhibitors such as infliximab and adalimumab are being used increasingly for the treatment of severe sight-threatening ocular inflammation including retinal vasculitis and cystoid macular edema (CME).

SUMMARY

Biological agents offer tremendous potential in the treatment of OBD. Given that OBD predominantly afflicts the younger adults in their most productive years, dermatologist, rheumatologist, internist, or general practitioners supervising patients with oculo-articulo-oromucocutaneous syndromes should be aware of systemic Behçet disease. Early recognition of ocular involvement is important and such patients should strongly be instructed to visit immediately an ophthalmologist, as uveitis management differs from extraocular involvements with high ocular morbidity from sight-threatening complications due to relapsing inflammatory attacks in the posterior segment of the eye. A single infliximab infusion should be considered for the control of acute panuveitis, whereas repeated long-term infliximab infusions were proved to be more effective in reducing the number of episodes in refractory uveoretinitis with faster regression and complete remission of CME.

The 27-bp VNTR polymorphism in intron 4 of the human eNOS gene in healthy Singaporean Chinese, Indians, and Malays

Human endothelial nitric oxide synthase (eNOS) is one isoform of the nitric oxide synthases that are responsible for nitric oxide synthesis from L-arginine. The gene encoding eNOS contains a 27-bp VNTR polymorphism in intron 4. We report here for the first time the presence of a novel allele 3, which was absent in all other populations studied to date, in 1.7% each of Singaporean Indians and Malays. We also detected the presence of a novel genotype 3/5 in 3.4% each of Singaporean Indians and Malays. Allele 6, which was absent in Han Chinese from northern China and Taiwan and was also absent in Indians from the Indian subcontinent, was found in 2.1% of Singaporean Chinese and in 0.3% of Singaporean Indians.

Prevalence of endothelial nitric oxide synthase (eNOS) gene exon 7 Glu298Asp variant in North Eastern India

BACKGROUND & OBJECTIVES

Endothelial nitric oxide is a potent vasodilator and impairment of its generation brought about by gene polymorphism is considered a major predictor for several diseases. A single nucleotide polymorphism G894T within exon 7 of endothelial nitric oxide synthase (eNOS-7) gene, resulting in a replacement of glutamic acid by aspartic acid, has been studied as a putative candidate gene for cardiovascular diseases. The pattern of eNOS-7 Glu298Asp variant in the Indian population is poorly known. The present study was planned to determine the prevalence of the variant of this gene among tea garden community in Assam, North-East India with high prevalence of hypertension.

METHODS

Study participants of both sex aged ≥18 yr were recruited randomly from temporary field clinics established in tea gardens of Dibrugarh, Assam. Genomic DNA was extracted from 409 subjects by the conventional phenol-chloroform method. The prevalence of the eNOS exon 7 Glu298Asp variant was determined by polymerase chain reaction and restriction fragment length polymorphism analysis.

RESULTS

The study population was in Hardy-Weinberg Equilibrium. The frequency of the eNOS GG, GT and TT genotypes was found to be 75, 22 and 3 per cent respectively and did not show any significant difference in gender wise analysis.

INTERPRETATION & CONCLUSIONS

Our results showed that the prevalence of the homozygous GG genotype was high (75%) and the rare mutant genotype (homozygous, TT) was 3 per cent in a population at risk with cardiovascular disease. Such population-based data on various polymorphisms can ultimately be exploited in pharmacogenomics.

The association between eNOS intron 4 VNTR polymorphism and delayed graft function of kidney allografts

Nitric oxide (NO) is a multifunctional agent which serves as a key signaling molecule in physiological processes such as host defense, neuronal communication, and the regulation of vascular tone. Different polymorphic variations have been identified in the human NOS3 (eNOS) gene.The aim of the present study was to examine the association between polymorphisms of the NOS3 gene (G894T substitution within exon 7 and intron 4 VNTR polymorphism) and the development of delayed graft function as well as acute and chronic rejection.One hundred eighty-seven recipients of first renal transplants were included in the study. There were no significant associations between these polymorphisms and acute and chronic kidney allograft rejection. The intron 4 polymorphism was associated with delayed graft function after transplantation. The results of this study suggest that patients with the a allele of the eNOS intron 4 VNTR polymorphism may be predisposed to delayed graft function.

Lack of association between common endothelial nitric oxide synthase gene haplotypes and left ventricular hypertrophy in hypertension

The endothelial nitric oxide synthase (NOS3) gene has been implicated in the pathogenesis of hypertension-related left ventricular hypertrophy (LVH). Candidate-gene studies have examined the role of NOS3 variation, but reported results are inconsistent. In this study, we investigated the association of three clinically relevant polymorphisms (promoter T786C, intronic 4a/b, and nonsynonymous G894T) in a case-control sample of 230 ethnically homogeneous (Caucasians) patients with essential hypertension, with (n = 64) and without (n = 166) clinically diagnosed LVH. Haplotype analysis was also performed. In single-marker analyses, no significant associations with LVH were detected by univariate and multivariate regression models. In the haplotype-based association analysis, no common haplotype was associated with the development of LVH. A rare haplotype consisting of the three mutant alleles (C-a-T*) was found to be present only in patients with LVH (3.4%) and not in control hypertensive patients. Despite the biological rationale for the involvement of the NOS3 gene in LVH, no evidence for a major role of common NOS3 haplotypic variation was found. Considering the totality of available evidence, single-gene analyses of the NOS3 gene have not uncovered detectable genetic effects, and pathway-based analyses that examine interactions of multiple loci may be more informative about the complex genetic etiology of LVH.

Behçet's Disease as a Model of Venous Thrombosis

Behçet's disease (BD) is a chronic inflammatory disease of unknown aetiology characterized by recurrent oral, genital aphthous ulcerations, uveitis, skin lesions and other multisystem affections associated with vasculitis. Different types of vessels, predominantly veins, can be affected in BD. The frequency of vascular lesions in BD, such as superficial and deep venous thromboses, arterial aneurysms and occlusions, ranges between 7-29%. In this review, various factors of thrombogenesis in BD, particularly pro- and antithrombotic endothelial and non-endothelial factors, factors of coagulation, platelet activation and rheological changes are presented and discussed from positions of Virchow's triad of venous thrombosis. Despite advances in understanding of thrombogenesis in BD, still many issues of diagnosis and targeted preventive and therapeutic measures remain unresolved. Further studies are needed to clarify the pathobiology of BD-related thrombosis and to provide the clinicians with recommendations over the utility, safety and effectiveness of the antithrombotic therapy in BD.

Behçet’s Disease as a Model of Venous Thrombosis

Behçet’s disease (BD) is a chronic inflammatory disease of unknown aetiology characterized by recurrent oral, genital aphthous ulcerations, uveitis, skin lesions and other multisystem affections associated with vasculitis. Different types of vessels, predominantly veins, can be affected in BD. The frequency of vascular lesions in BD, such as superficial and deep venous thromboses, arterial aneurysms and occlusions, ranges between 7-29%.

In this review, various factors of thrombogenesis in BD, particularly pro- and antithrombotic endothelial and non-endothelial factors, factors of coagulation, platelet activation and rheological changes are presented and discussed from positions of Virchow’s triad of venous thrombosis.

Despite advances in understanding of thrombogenesis in BD, still many issues of diagnosis and targeted preventive and therapeutic measures remain unresolved. Further studies are needed to clarify the pathobiology of BD-related thrombosis and to provide the clinicians with recommendations over the utility, safety and effectiveness of the antithrombotic therapy in BD.

AnNOS3Haplotype Is Protective against Hypertension in a Caucasian Population

The endothelial nitric oxide synthase gene (NOS3) has been implicated in the development of hypertension, although the specific role of variants and haplotypes has not been clarified. In this study, the association of three polymorphisms (promoter T786C, intronic 4a/b, and nonsynonymous G894T) was tested in a case-control sample of 230 patients with essential hypertension and 306 healthy controls. Haplotype analysis was also performed. The mutant allele a^∗ of the 4a/b polymorphism showed a protective effect against hypertension under a dominant model (odds ratio = 0.64, 95% confidence interval (0.44–0.93)), although this effect was not significant after the adjustment for covariates (P = 0.06). The estimated frequency of the haplotype composed of the T786^∗, 4a^∗, and G894^∗ alleles was significantly higher in controls (5.5%) compared to cases (2%). These results indicate that although individual NOS3 polymorphisms are not associated with hypertension, a rare haplotype of the gene might be protective against the development of hypertension.

Endothelial nitric oxide synthase and nicotinamide adenosine dinucleotide phosphate oxidase p22phox gene (C242T) polymorphisms and systemic lupus erythematosus in a Chinese Population

Genetic polymorphisms in the endothelial nitric oxide synthase (eNOS) and nicotinamide adenosine dinucleotide phosphate (NADPH) oxidase p22phox are linked with the expression and/or progression of vascular disease. We hypothesized that these polymorphisms may influence the development and/or progression of systemic lupus erythematosus (SLE), given their linkage with vascular disease. DNA from patients with SLE (n = 90) and their age- and sex-matched controls (n = 86) from The Second Xiangya Hospital of Central South University was assessed for eNOS and NADPH oxidase p22phox polymorphisms. These polymorphisms were examined by restriction fragment length polymorphism-polymerase chain reaction. The allele frequency of the NADPH oxidase p22phox gene C242T polymorphisms significantly varied between the SLE patients and the controls. We found no association of the eNOS polymorphism with the development of renal disease. These results indicated that the etiology of patients with SLE is associated with NADPH oxidase p22phox gene C242T polymorphisms. There was no significant increased risk of SLE associated with eNOS polymorphisms in the Chinese population.

eNOS G894T polymorphism and abdominal aortic aneurysms

BACKGROUND

The genetic risk factors that contribute to the risk of developing abdominal aortic aneurysm (AAA) are poorly understood. We assessed the association of endothelial nitric oxide synthase (eNOS) gene polymorphism with AAA.

METHODS

eNOS gene polymorphism of 61 patients with AAA and 62 control participants were analyzed by polymerase chain reaction (PCR)-restriction technique.

RESULTS

eNOS G894 homozygote T/T genotype polymorphism and 894T allele frequency in patients with AAA were significantly higher than those of the control participants (P = .01, P = .03). Among patients with AAA, the eNOS G894 T/T polymorphism and 894T allele frequency were associated with larger AAAs.

CONCLUSION

The current study, in a small group of participants, showed a relationship between eNOS G894T polymorphism and AAA.

Endothelial nitric oxide synthase gene polymorphisms are not associated with recurrent aphthous stomatitis

OBJECTIVE

Recurrent aphthous stomatitis (RAS) is a common ulcerative disease of the oral mucosa. Recurrent oral aphthous ulceration is the most common and consistent feature of the more serious and systemic Behçet's disease (BD). Association of endothelial nitric oxide synthase (eNOS) gene polymorphisms with BD have been reported in different populations. This study aims to investigate if there is an association between these polymorphisms and RAS.

METHODS

A case-control association study using 91 Caucasoid RAS patients and 91 ethnically matched systemically healthy controls were genotyped for the -786 and 894 eNOS single nucleotide polymorphisms (SNPs) and a variable number of tandem repeat (VNTR) polymorphism. Chi-square analysis was used to compare the allele and genotype frequencies.

RESULTS

No significant difference was found in the distribution of allele and genotype frequencies of the -786 and +894 polymorphisms or the VNTR polymorphism between cases and controls.

CONCLUSION

eNOS gene polymorphisms associated with BD are not associated with RAS. This suggests that the oral ulceration common to both conditions may have a different underlying genetic aetiology. Although our data suggests that RAS does not have an association with eNOS, it is still possible that nitric oxide is involved in the disease process. This could still occur through localised and inflammation driven regulation by iNOS.

Protective role of 27bp repeat polymorphism in intron 4 of eNOS gene in lacunar infarction

Association of the three potential endothelial nitric oxide synthase gene (eNOS) polymorphisms (T-786C in promoter region, G894T in exon 7 and tandem 27-bp repeats in intron 4) with an increased risk of lacunar infarction (LI) were investigated. Genotypes of 70 patients and 81 healthy controls were determined through PCR with or without RFLP. Flow-mediated dilatation (FMD) was performed to assess endothelial-dependent vasodilatation, whereas the endothelial-independent vasodilatation was assessed with nitroglycerin (NTG). Genotype distribution was significantly different between LI patients and controls for intron 4aa (alleles for four repeats), genotype frequency being 1.4% and 16.0%, respectively (odds ratio for additive effect, 0.47; 95% CI, 0.28-0.81; p=0.006). Haplotypes with the intron 4aa polymorphism were significantly higher in controls when compared with the LI group (p=0.001). Diminished FMD but normal NTG response confirmed that patients with LI have generalized endothelial dysfunction. Intron 4aa genotype of eNOS gene seems to be protective for isolated LI and the effect was potentiated by the absence of 786C polymorphism in any allele of the promoter region.

Endothelial nitric oxide synthase gene polymorphisms in non-arteritic anterior ischemic optic neuropathy

BACKGROUND

To examine the association between the polymorphisms of the endothelial nitric oxide synthase (eNOS) gene and the occurrence of non-arteritic anterior ischemic optic neuropathy (NAION).

METHODS

We studied 15 patients with NAION (mean age, 62 years; 60% male). 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 NAION was compared with the control (mean age, 63 years; 63% male) distribution.

RESULTS

There was no significant difference in the genotype distribution of the Glu298Asp polymorphism between the NAION and control groups (P = 1.000), whereas the genotype dis-tribution of the T(-786)C polymorphism varied significantly between the patients with NAION and control subjects (P = 0.002). After adjusting on covariates, individuals with the CC genotype of the T(-786)C polymorphism were more likely to develop NAION compared with those with TT genotype (odds ratio = 0.09: 95% CI 0.01-0.86).

CONCLUSIONS

We found an increased prevalence of T(-786)C polymorphism of the eNOS gene in patients with NAION. Our data suggest that the T(-786)C polymorphism of the eNOS gene may be an important risk factor in the development of NAION in Japanese subjects.

HLA-B51 gene and its expression in association with Behçet’s Disease in Denizli Province of Turkey

Behçet's Disease (BD) is a multisystemic inflammatory disorder as a triad of symptoms including recurrent oral and genital aphthous ulceration, and uveitis with unknown pathogenesis. Many researchers have tried to investigate the association of HLA-B51 gene with the BD. We aimed to investigate the association of the HLA-B51 gene and its expression, also polymorphic structure by PCR, RT-PCR and sequence specific oligonucleotide primers and probes in BD patients (n: 35) and control group (n: 50). According to our results, we did not observe any association in between HLA-B51 gene, its polymorphism, expression and BD patients.

Intima-media thickness and arterial stiffness of carotid artery in Korean patients with Behçet's disease

Behçet's disease (BD) is a systemic vasculitis involving diverse sizes of arteries and veins. We performed this study to evaluate the vascular changes by assessment of the arterial stiffness and intima-media thickness (IMT) of carotid artery in Korean patients with BD. Forty-one patients with BD and age-, and sex-matched 53 healthy subjects were recruited in this study. Carotid arterial stiffness and IMT were assessed by using high-resolution B-mode ultrasonography. Arterial stiffness parameters such as carotid arterial distensibility coefficient, stiffness index, and incremental elastic modulus (E(inc)) were significantly increased in BD patients compared with those in healthy subjects, but not in IMT. Positive relationship was noted between age and IMT, whereas age of onset was significantly associated with arterial stiffness in BD. This finding suggests impaired endothelial function before visible structural changes of arterial wall in BD. Age and age of onset may be an independent risk factor for carotid IMT and arterial stiffness, respectively. Further studies in more large populations are required to confirm our results.

Increased endothelin-1 levels of BAL fluid in patients with Behçet's disease

Objective and background. Pulmonary aneurysms and thrombosis constitute a significant cause of morbidity and mortality in Behçet's disease (BD). Various factors have been studied to explore the pathogenesis of vascular involvement in BD. As endothelin (ET) is known for its potent vasoconstrictor and proinflammatory properties, we supposed that it is involved during the inflammatory process of BD pulmonary vasculitis. Methods. To investigate the role of ET in BD, ET-1 concentrations were measured in bronchoalveolar lavage fluid (BALF) of 18 nonsmoking BD patients with pulmonary manifestations and 12 control subjects. Immunoreactivity of ET-1 was also evaluated in alveolar macrophages (AMs) cytoplasm. Results. ET-1 levels in BD-BALF were significantly higher than those of controls. ET-1 levels were correlated with the number of alveolar macrophages, but not with BAL-CD4/CD8 ratio. ET-1-immunoreactivity was found mainly in AM of BD-BAL. Conclusions. Increased ET-1 production from AM is associated with pulmonary BD manifestations.

Analysis of CD28 and CTLA-4 gene polymorphisms in Turkish patients with Behcet's disease

In this study we aimed to investigate IVS3 +17T/C single nucleotide polymorphism (SNP) of CD28 gene, +49A/G and -318C/T SNPs of CTLA-4 gene in patients with Behçet's disease (BD) and their potential association to the main clinical features of the disease. These polymorphisms were investigated in a Turkish population of 123 patients with BD and 179 healthy controls, by using PCR-RFLP technique. HLA-B*51 genotype was also studied in both groups by using PCR-SSP. The frequency of IVS3 +17TC genotype of the CD28 gene was significantly increased in BD patients compared to controls (43.6% vs. 31.2%, OR = 1.663, 95% CI = 1.033-2.679, P = 0.039). CTLA-4 +49GG genotype frequency was found to be significantly lower in patients with BD than those of healthy controls (4% vs. 10.6%, OR = 0.357, 95% CI = 0.130-0.983, P = 0.05). Genotype and allele frequencies of the CTLA-4-318C/T polymorphism between the BD and healthy control groups were not significantly different (12.2% vs. 10.6%, OR = 1.170, 95% CI = 0.570-2.402, P = 0.713). There were no associations between the studied polymorphisms and the main clinical features of BD. The frequencies of HLA-B*51 were 60.3% and 30.7% in BD and control groups, respectively (OR = 3.429, 95% CI = 2.115-5.559, P = 0.0001). Association between HLA-B*51 and each studied polymorphism did not reach to significant levels (OR = 0.479, 95% CI = 0.228-1.004, P = 0.064 for CD28 IVS3 +17TT genotype; OR = 2.180, 95% CI = 1.025-4.639, P = 0.061 for TC genotype; OR = 1.570, 95% CI = 0.870-2.836, P = 0.146 for C allele). These results may suggest that CD28 IVS3 +17TC genotype may be a risk factor for the development of BD, on the contrary CTLA-4 +49GG genotype may be protective in the studied Turkish population.

Endothelial nitric oxide synthase gene polymorphisms and cardiovascular disease: a HuGE review

This review examines the association of a subset of endothelial nitric oxide synthase gene (NOS3) polymorphisms (Glu298Asp, intron 4, and -786T>C) with cardiovascular disease. The Glu298Asp polymorphism within exon 7 is the only common nonsynonymous variant. The variants have been associated with low plasma nitric oxide concentrations and reduced vascular reactivity; difficulties in measuring those phenotypes means that their functional role remains unclear. A large meta-analysis of NOS3 polymorphisms in coronary heart disease revealed per-allele odds ratios of 1.17 (95% confidence interval: 1.07, 1.28) for Glu298Asp, 1.17 (95% confidence interval: 1.07, 1.28) for -786T>C, and 1.12 (95% confidence interval: 1.01, 1.24) for intron 4. However, there was evidence that small studies with more striking results could affect the associations of the Glu298Asp and -786T>C polymorphisms with coronary heart disease. Associations of NOS3 polymorphisms with hypertension, preeclampsia, stroke, and diabetes remain uncertain. To date, no reliable gene-gene or gene-environmental interactions have been described. Use of these variants in predictive testing is unlikely to be useful, although the population attributable fraction could be substantial if the modest associations are causal. The need for large-scale genetic association studies using tagging polymorphisms is warranted to confirm or refute a role of the NOS3 gene in coronary heart disease.

Physiopathologie de la maladie de Behçet

SUBJECT

Pathophysiology of Behçet's disease (BD) is complex. Recent experimental data shed new light on the mechanisms leading to organ lesions.

MAIN ISSUES

Neutrophils and cytotoxic lymphocytes are now recognized as key effector cells in BD. Genetic susceptibility, environmental factors (virus and/or bacterial infections), inflammatory response abnormalities (heat shock proteins, dysregulated NO production) and abnormal immune response play also a major role in BD pathogeny.

PERSPECTIVES

Better understanding of the BD pathophysiology will allow the development of new therapies more specific of BD.

Endothelial nitric oxide synthase gene polymorphisms in patients with nontraumatic femoral head osteonecrosis

As endothelial nitric oxide synthase (eNOS) has beneficial effects on skeletal, vascular, and thrombotic systems, the association between nontraumatic femoral head osteonecrosis (FHON) and eNOS gene polymorphisms was investigated in Korean patients with FHON. Genomic DNA from 103 patients with nontraumatic FHON (idiopathic in 50, steroid-induced in 29, and alcohol abuse in 24) and 103 control subjects matched for gender and age (3-year range) was analyzed for the 27-bp repeat polymorphism in intron 4 and Glu298Asp polymorphism in exon 7. The frequencies of alleles and genotypes were compared between patients and control subjects. The frequency of 4a allele was significantly higher in total patients than control subjects [6.8% vs. 2.4%, p = 0.0345, odds ratio (OR) 2.931]. In subgroup analysis, the 4a allele significantly increased in patients with idiopathic FHON versus control subjects (9.0% vs. 2.4%, p = 0.0297, OR 3.976). The frequency of the 4a/b genotype in total patients (13.6% vs. 4.9%, p = 0.0302, OR 3.083) as well as patients with idiopathic FHON (18.0% vs. 4.9%, p = 0.0246, OR 4.302) was higher than control subjects. The distribution of Glu298Asp polymorphisms was not significantly different between patients and control subjects. Microstellate polymorphism in intron 4 of eNOS polymorphism was significantly associated with idiopathic FHON in Korean patients. Because 4a allele is associated with lower synthesis of eNOS, these results suggest that carrier state of 4a allele in intron 4 might be a genetic risk factor of FHON and could provide insight into the protective role of nitric oxide in the pathogenesis of FHON.

Evaluation of leptin level and Ob gene polymorphism in patients with Behcet's disease

The present study was aimed to evaluate serum leptin level and the frequency of oligopolymorphic codon 25 (CAA/CAG) of Ob gene in Behcet's disease. Eighty-seven patients with Behcet's disease and 85 healthy controls with matched age, gender and body mass index were included in the study. Serum leptin level was determined and genotype of codon 25 of Ob gene was performed by using the PCR amplification after DNA extraction. Serum leptin concentration of the patients with Behcet's disease (23.8 +/- 22.8 ng/ml) was higher than that of the control groups (17.1 +/- 14.7 ng/ml). The patients with Behcet's disease and control subjects showed CAA/CAA genotype, indicating the presence of no polymorphism. Neither Behcet's disease nor serum leptin level was found to be related to codon 25 polymorphism. We concluded that leptin 25CAG polymorphism is not associated with Behcet's disease and serum leptin level.

Lack of evidence for association between endothelial nitric oxide synthase gene polymorphism (glu298asp) with Behçet’s disease in the Turkish population

Endothelial nitric oxide synthase (eNOS) could be a candidate gene for Behçet's disease (BD). This study investigated the relationship of the eNOS Glu298 --> Asp polymorphism with the presence and severity of BD in the Turkish population. Ninety-two patients with BD and 100 controls were studied. Analyses of Glu298Asp polymorphism in exon 7 of the eNOS gene were made by the polymerase chain reaction (PCR)-restriction fragment length polymorphism technique. The frequencies of the eNOS genotypes were similar for BD patients (GG:GT:TT = 58.7%:38%:3.3%) and controls (59.2%:33.7%:7.1 %), P = 0.335. No evidence of difference was found in the frequency of the T allele between BD patients (22.3%) and controls (24%), [OR = 0.91, 95% CI (0.55-1.50), P = 0.690]. Glu298 --> Asp polymorphism of the eNOS gene does not appear to be associated with the presence of BD in the Turkish population.

Synovial nitric oxide concentrations are increased and correlated with serum levels in patients with active Behçet's disease: a pilot study

Behçet's disease (BD) is a relapsing immunoinflammatory vasculitis of unknown etiology characterized by endothelial dysfunction. Articular symptoms and signs are present in about 75% of cases and characterized by seronegative arthritis and nonspecific synovitis. We demonstrated that both serum and erythrocyte nitric oxide (NO(.)) levels, the most abundant free radical in the body, were elevated in BD and associated with disease activity. This study further investigated NO(.) levels in the synovial fluid and serum from patients with active and inactive BD. A total of 23 BD patients with articular involvement (14 men and 9 women) satisfying International Study Group criteria and 15 age- and sex-matched healthy control subjects (9 men and 6 women) undergoing elective arthroscopy were included in this case-control investigation. The synovial fluid and serum were obtained from BD patients and controls. Clinical and laboratory findings including neutrophil count and erythrocyte sedimentation rate (ESR) were used to classify BD patients as active (n = 11) or inactive (n = 12). Synovial as well as serum NO(.) levels were compared between the groups and correlation analysis was performed. Acute phase reactant levels were significantly higher (for each, p < 0.01) in BD patients than control subjects in the active period. The mean synovial NO(.) level in active Behçet's patients (mean +/- SD 76.61 +/- 11.95 micromol/l) was significantly higher than in inactive patients (46.16 +/- 8.89 micromol/l, p < 0.001) and healthy control subjects (39.60 +/-8.03 micromol/l, p < 0.001). The difference between inactive patients and controls was not significant (p > 0.05). Active BD patients had significantly higher serum NO(.) levels (38.84 +/- 9.15 micromol/l) than inactive patients (30.91 +/- 5.88 micromol/l, p = 0.018) and control subjects (28.86 +/- 5.91 micromol/l, p = 0.002). In addition, synovial NO(.) levels were positively correlated with serum levels (r(2) = 0.621, p < 0.001). Increased synovial NO(.) levels in active BD patients probably reflect a nonspecific inflammatory process of the synovium and, therefore, arthralgia and arthritis as a common finding of BD.

Endothelial cell dysfunction in systemic vasculitis: new developments and therapeutic prospects

PURPOSE OF REVIEW

The role of the endothelium as an active player rather than a passive victim of inflammation has received considerable interest in atherosclerosis, but less so in systemic vasculitis (SV). However, the accumulating multi-organ damage seen in SV probably includes the endothelium. Assessment of endothelial function is now a standard clinical research tool in cardio-vascular departments. The exciting insights provided by their application to SV, in both primary disease and connective tissue diseases (CTD), is reviewed here.

RECENT FINDINGS

Diffuse endothelial cell dysfunction (ECD) documented by several techniques occurs commonly in adult and childhood SV. Similar ECD is also seen in CTD. The mechanisms probably relate to inflammatory cytokines such as TNF. The particular role of vasculitic, as opposed to synovial or internal organ inflammation, may be release of secondary mediators directly into the blood stream- whence they can reach distant endothelial beds to induce this diffuse ECD.

SUMMARY

Endothelial injury is the first step in atherosclerosis, where peripheral abnormalities correlate with coronary artery responses. The diffuse ECD in CTD suggests that vascular inflammation may initiate the accelerated CVS disease there. The new findings of similar ECD in primary SV predicts enhanced atherosclerosis here too. In Kawasaki syndrome, persistent late ECD correlates with abnormal coronary responses. In adult SV, initial data also suggests increased subclinical atherosclerosis. The role of endothelial function in the clinical outcome of SV deserves more attention. Research to pinpoint the mechanisms of ECD should lead to more specific therapies that may ameliorate the continuing late morbidity and mortality of SV.

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

OBJECTIVE

Reduced plasma nitric oxide (NO) levels in Behçet'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.