Influence of eNOS Gene Polymorphisms on Carotid Atherosclerosis

Genetic association between eNOS gene polymorphisms and risk of carotid atherosclerosis : A meta-analysis

BACKGROUND

Endothelial nitric oxide synthase (eNOS) has been reported to be involved in the atherosclerotic process. A number of studies have investigated the association between eNOS gene polymorphisms and the risk of carotid atherosclerosis (CAS). However, the results are conflicting and inconclusive. The aim of this study was to evaluate precisely the association between the eNOS T786C, G894T, and 4a/4b polymorphisms and CAS risk.

MATERIAL AND METHODS

A meta-analysis was carried out by retrieving relevant studies from PubMed, Embase, China National Knowledge Infrastructure (CNKI), and Cochrane databases without a restriction on publication year. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to describe the strength of the association with CAS.

RESULTS

Data were obtained from eight case-control studies comprising 2975 cases and 2624 controls. Significant associations were detected between the allelic and recessive models of the eNOS T786C polymorphism (allelic: p = 0.04; OR, 95% CI = 1.57 [1.01, 2.44]; recessive: p = 0.03; OR, 95% CI = 1.53 [1.04, 2.24]), as well as the allelic and dominant models of the eNOS 4a/4b polymorphism, and CAS risk in an Asian subgroup (allelic: p = 0.02; OR, 95% CI = 1.49 [1.07, 2.07]; dominant: p = 0.01; OR, 95% CI = 1.50 [1.09, 2.05]), but not in a Caucasian subgroup (p > 0.05). No association was observed between the eNOS G894T polymorphism and CAS risk (p > 0.05).

CONCLUSION

Our study provides evidence that the allelic and recessive models of the eNOS T786C polymorphism and the allelic and dominant models of the eNOS 4a/4b polymorphism may increase the risk of CAS in Asian populations.

High sensitivity C-reactive protein as a predictive of intima-media thickness in patients with end-stage renal disease on regular hemodialysis

BACKGROUND

Several emerging problems of regular hemodialysis (HD) including cardiovascular complication or atherosclerosis formation caused by chronic inflammation. Intima-media thickness (IMT) of the carotid artery can be applied as a marker of atherosclerosis progression. This study was designed to identify the predictive of IMT progression among end-stage renal disease (ESRD) subject.

METHODS

This cohort study was performed at the Hemodialysis Unit of Dr. Kariadi Hospital and Telogorejo Hospital Semarang between October 2009 and April 2010. The study subjects were the ESRD patients with regular HD.

RESULTS

This study enrolled 78 subjects with regular HD, follow-up 6 months. The subjects which completed the study were divided into two groups that consist of IMT progressive group (n=53) and IMT non-progressive group (n=12). There were no differences between two groups according to age, gender, history of diabetes, blood pressure, duration of HD, urea, creatinine, blood glucose, HbA1C, cholesterol, triglyceride, HDL, uric acid, phosphate, calcium, homocysteine, and albumin. Subject with high-sensitive C-reactive protein (hsCRP) level >0.52 mg/L had an IMT progression. There was a correlation between hsCRP and the thickening of carotid artery wall after 6-month HD (RR=3.6; 95% CI=2.2-22.9). The subject with hsCRP level >9.00 mg/L after 6-month dialysis progress to thickening of carotid artery wall of >0.03 mm. There was a correlation between hsCRP level (cut-off point: 9.0 m/L) and the progression of the carotid artery wall (RR=2.1; 95% CI=1.3-3.37). Statistically, there was no correlation between IL-6-174 G/C gene and eNOS gene polymorphism with IMT progression.

CONCLUSION

hsCRP is a significant predictive of IMT progression at hemodialysis subject. IL -174 G/C gene and eNOS gene polymorphism are not significant predictive of IMT progression at hemodialysis subject.

MicroRNA-155 induces protection against cerebral ischemia/reperfusion injury through regulation of the Notch pathway in vivo

microRNA (miR)-155 has been demonstrated to participate in the regulation of endothelium during cerebral ischemia. In the present study, it was aimed to investigate the molecular mechanism of miR-155 in the regulation of cerebral ischemia/reperfusion (I/R) injury with middle cerebral artery occlusion (MCAO) in mice. The MCAO model was established in C57BL/6 mice. Transfection of miR-155 mimics and miR-155 inhibitors was performed to alter the expression of miR-155. The level of miR-155 was measured by RT-qPCR analysis. The western blotting results demonstrated that deletion of miR-155 increased the expression of Notch1, intracellular Notch receptor domain (NICD) and hairy and enhancer of split-1 (Hes1) levels. In addition, the percentage of terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling-positive cells and caspase-3 levels were decreased following treatment with a miR-155 inhibitor compared with the Pre-IR group. Notably, disrupting miR-155 also increased nitric oxide (NO) production and the expression of endothelial NO synthase (eNOS), leading to downregulation of brain water content and Evans blue levels. However, overexpression of miR-155 restored all these changes to similar levels observed in the cerebral I/R injury group. The expressions of Notch1, NICD and Hes1 were also decreased to the cerebral I/R injury condition. In conclusion, a novel mechanism was identified for abrogating normal NO production and eNOS expression via the aberrant expression of the Notch signaling pathway, a mechanism that may be modulated by miR-155. Together, these results reveal important functions of miR-155 in regulating the Notch signaling pathway of the nervous system, and a potential role for miR-155 as a crucial therapy target for cerebral stroke.

Genetic association study between T-786C NOS3 polymorphism and essential hypertension in an Algerian population of the Oran city

BACKGROUND

Essential hypertension is an important risk factor for the development of cardiovascular disease. Important candidate genes such as NOS3 gene have been widely studied and reported to be associated with essential hypertension (HTN) in human populations.

AIM

We aim in this study to analyze the relationship between NOS3 -786T/C, a common genetic variant and HTN in a sample of the Algerian population of the Oran city.

METHODS

A case-control study has been performed in 154 subjects including 77 hypertensives and 77 normotensives. The recruitment of these subjects was done in local Health Centers of the city of Oran, West Algeria. HTN was defined as elevated systolic blood pressure SBD≥140  mmHg and or sustained diastolic blood pressure DBP≥90  mmHg, measured using an Omron^® Automatic BP Monitor - M-3W machine. Consents were obtained from all participants. Polymerase chain reaction (PCR) combined with restrictive fragment length polymorphism (RFLP) was used to genotype the NOS -786T/C variant.

RESULTS

The distribution of the allelic frequencies did not differ between cases and controls (OR = 1.48; 95%CI [0.94-2.32], P = 0.09). However, after adjustment with the age, sex, and body mass index, we observed significant association between NOS -786C allele and HTN status (OR = 2.08; 95%CI [1.18-3.66], P = 0.01).

CONCLUSION

Our results indicate that the C allele of the NOS3 gene is associated with increased risk of essential hypertension in this sample of the Algerian population of the Oran city. Further validation in larger samples is needed to confirm this finding.

eNOS Gene Affects Red Cell Deformability: Role of T-786C, G894T, and 4a/4b Polymorphisms

Plasma viscosity and erythrocyte deformability play a key role in maintaining and regulating microcirculation. In vitro and in vivo studies suggested a role for nitric oxide (NO) in modulating flow-mediated vasodilatation and red blood cell deformability. Impaired NO availability due to mutations in eNOS gene might contribute to the altered haemorheologic state. The aim of this study was to investigate the role of eNOS T-786C, G894T, and 4a/4b polymorphisms in modulating the haemorheologic state in a clinical condition characterized by a microcirculatory disorder. Eighty patients with idiopathic sudden sensorineural hearing loss (ISSHL) and 80 healthy subjects were studied. By using a dominant model of inheritance, we found a significant association between eNOS 894T rare variant and ISSHL (odds ratio [OR] 894TT+GT = 2.08, p = 0.03) after adjustment with traditional vascular risk factors. A higher percentage of altered red cell deformability both in patients and in controls carrying the eNOS rare variants was found in comparison to subjects carrying the wild type. Apart from the disease, eNOS T-786C and G894T polymorphisms independently affected the deformability index (OR,-786CC+TC = 2.81, p = 0.01 and OR, 894TT+GT = 2.5, p = 0.02, respectively), in particular in subjects in whom the contemporary presence of the two rare alleles was observed (OR,-786CC+TC and 894TT+GT combined genotype = 6.9, p<0.0001). Our study documented that eNOS gene affects the red blood cell deformability, so possibly contributing to ISSHL, which may represent a suitable model of microcirculatory disorder.

Partial eNOS deficiency causes spontaneous thrombotic cerebral infarction, amyloid angiopathy and cognitive impairment

Background

Cerebral infarction due to thrombosis leads to the most common type of stroke and a likely cause of age-related cognitive decline and dementia. Endothelial nitric oxide synthase (eNOS) generates NO, which plays a crucial role in maintaining vascular function and exerting an antithrombotic action. Reduced eNOS expression and eNOS polymorphisms have been associated with stroke and Alzheimer’s disease (AD), the most common type of dementia associated with neurovascular dysfunction. However, direct proof of such association is lacking. Since there are no reports of complete eNOS deficiency in humans, we used heterozygous eNOS^+/- mice to mimic partial deficiency of eNOS, and determine its impact on cerebrovascular pathology and perfusion of cerebral vessels.

Results

Combining cerebral angiography with immunohistochemistry, we found thrombotic cerebral infarctions in eNOS^+/- mice as early as 3–6 months of age but not in eNOS^+/+ mice at any age. Remarkably, vascular occlusions in eNOS^+/- mice were found almost exclusively in three areas: temporoparietal and retrosplenial granular cortexes, and hippocampus this distribution precisely matching the hypoperfused areas identified in preclinical AD patients. Moreover, progressive cerebral amyloid angiopaphy (CAA), blood brain barrier (BBB) breakdown, and cognitive impairment were also detected in aged eNOS^+/- mice.

Conclusions

These data provide for the first time the evidence that partial eNOS deficiency results in spontaneous thrombotic cerebral infarctions that increase with age, leading to progressive CAA and cognitive impairments. We thus conclude that eNOS^+/- mouse may represent an ideal model of ischemic stroke to address early and progressive damage in spontaneously-evolving chronic cerebral ischemia and thus, study vascular mechanisms contributing to vascular dementia and AD.

Electronic supplementary material

The online version of this article (doi:10.1186/s13024-015-0020-0) contains supplementary material, which is available to authorized users.

Endothelial nitric oxide synthase intron 4a/b polymorphism in coronary artery disease in Thrace region of Turkey

Coronary artery disease (CAD) is one of the frequent cardiovascular mortality causes in the world. Common risk factors explain only about half the risk of CAD. The healthy familial predisposition to CAD, combined with advances in genetic analysis, has led to a number of studies in recent years making an effort to identify the genetic factors that influence the risk. The approach taken by most studies was to examine the association of naturally occurring genetic polymorphisms in candidate genes with risk of or severity of CAD. Endothelial nitric oxide synthase (eNOS) is important for vascular and tissue protection and is found in endothelial cells that encompass the entire vasculature, including the vessels in the heart. Nitric oxide (NO) is produced in a catabolic reaction in the endothelial cells, neurons, glia and macrophages by nitric oxide synthase (NOS) isoenzymes. eNOS is a subgroup of this family of enzymes that catalyses the production of nitric oxide (NO) from L-arginine and oxygen, which leads to vascular relaxation by activating the guanylate cyclase. This finally induces smooth muscle relaxation. The aim of this study was to investigate the allelic frequency and the genotypic distribution of the variable number of tandem repeat 27 (27 VNTR) gene polymorphism in intron 4 of the eNOS (eNOS 4a/b) gene in Thrace region, to compare CAD patients with appropriate healthy controls and to correlate the genetic findings with CAD subtypes. The study group included 281 (153 subjects with CAD and 128 controls) patients. The eNOS polymorphism was identified with a polymerase chain reaction. Genotypes were defined as aa, ab and bb according to the presence of a and b alleles. In this case–control study, we found that there was sensible correlation between eNOS gene intron 4a/b VNTR polymorphism and the risk of CAD in Thrace region of Turkey. However, there was no major difference for the genotype distribution and the allelic frequency among the CAD subtypes. Further studies on the interaction of such genes are needed to clarify the association between eNOS 4a/b polymorphism and CAD patients.

Incidence, risk factors, treatment and prognosis of popliteal artery embolization in the superficial femoral artery interventions

Objective

Percutaneous transluminal angioplasty and stenting (PTA + stent) has gained acceptance as a primary treatment modality for the superficial femoral artery (SFA) diseases. Popliteal artery embolization (PAE) is a severe complication in SFA interventions. The purpose of this study was to evaluate the incidence, risk factors, treatment and prognosis of PAE in primary SFA PTA + stent.

Methods

Chronic SFA arteriosclerosis cases that underwent primary PTA + stent were reviewed from a retrospectively maintained database. Runoff vessels were evaluated in all cases before and after the interventions for PAE detection. The primary patency, secondary patency and limb salvage rates were calculated using Kaplan-Meier analysis and compared using log-rank analysis. Cox multivariate regression was performed to evaluate predictors of patency and limb salvage rates.

Results

There were 436 lesions treated in 388 patients with 10 PAE events (2.3%) in total. PAE rate was significantly higher in Transatlantic Inter-Society Consensus (TASC) C/D group compared with TASC A/B group (OR = 8.91, P = .002), in chronic total occlusion (CTO) lesions compared with stenotic lesions (P<.0001), and in group with history of cerebral ischemic stroke (OR = 6.11, P = .007). PAE rates were not significantly affected by age, sex, smoking, hypertension, diabetes, hyperlipidemia and runoff status. The binary logistic regression showed that only the TASC C/D was an independent predictor of PAE (P = .031). The 12-month and 24-month primary patency, secondary patency and limb salvage rates in PAE group showed no significant differences comparing with non-PAE group.

Conclusions

PAE is a rare event in primary SFA PTA + stent. TASC C/D lesion, CTO and cerebral ischemic stroke history are risk factors for PAE. PAE is typically reversible by comprehensive techniques. If the popliteal flow is restored in time, PAE has no significant effect on long-term patency and limb salvage rates.

Effect of the +781C/T polymorphism in the interleukin-8 gene on atherosclerotic cerebral infarction, and its interaction with smoking and drinking

OBJECTIVE

The aims of this study were to investigate the association between the +781C/T polymorphism of interleukin-8 (IL-8) and atherosclerotic cerebral infarction and the interaction between the +781C/T polymorphism and smoking or drinking in cerebral infarction in the Han Chinese population.

METHODS

We investigated the +781C/T polymorphism of IL-8 in 308 consecutive Han Chinese patients who were diagnosed with atherosclerotic cerebral infarction and in 294 age- and gender-matched healthy control subjects. The patients were classified using the Oxfordshire Community Stroke Project (OCSP) classification. The patients and subjects' histories of smoking and drinking were recorded, and atherosclerosis (AS) of the internal carotid artery (ICA) was evaluated in the patients. The +781C/T polymorphism was determined by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis.

RESULTS

The +781C/T polymorphism and allele frequencies were not significantly different between the patients and controls and were not significantly associated with the OCSP classifications. We found that the 781C allele was significantly associated with AS of the ICA in the patients (p = 0.017), and the CT genotype was more prevalent in patients without AS of the ICA (p = 0.035). No interactions were observed between the +781C/T polymorphism and smoking or drinking.

CONCLUSION

Our results demonstrated that the +781C/T polymorphism of IL-8 did not play a role and had no interaction with smoking or drinking in the occurrence of cerebral infarction in the Han Chinese population. However, the C allele and the CT genotype might be associated with AS of the ICA in patients with ischemic stroke.

Polymorphisms of the NOS3 gene and risk of myocardial infarction in the Tunisian population

Controversial results regarding the association of eNOS gene (NOS3) polymorphisms with myocardial infarction (MI) have been reported. This study investigated the relationship of the -786T>C (rs2070744), 894G>T (rs1799983) and 4a4b polymorphisms of the NOS3 gene with the presence of MI in the Tunisian population. In addition, we also examined the association of NOS3 gene haplotypes with MI in Tunisian subjects. A total of 303 patients with MI and 225 controls were included in the study. The 894G>T and -786T>C single nucleotide polymorphisms were analyzed by PCR-RFLP, and 4a4b polymorphism just for PCR. There was significant linkage disequilibrium between the three NOS3 polymorphisms (p<0.0001). The genotype distribution and allele frequency of NOS3 4a4b, but not -786T>C and 894G>T, polymorphism was significantly different between MI patients and controls. The univariate logistic regression analysis showed a significant association of the 4a4b polymorphism and MI according to co-dominant, dominant and recessive models (co-dominant model OR: 4.38, 95%CI: 1.24-15.41; p=0.021, dominant model OR: 1.66, 95%CI: 1.14-2.42); p=0.007, and recessive model OR: 3.85, 95%CI: 1.10-13.47; p=0.035). The multivariate analysis, adjusted for traditional cardiovascular risk factors, revealed that the NOS3 4a4a genotype was an independent predisposing factor to MI, according to the models considered. In addition, a haplotype 7 (C-T-4a), (OR=12.05, p=0.010) was a risk factor of MI after controlling for classical risk factors. These finding suggest that the 4a4b polymorphism of the NOS3 gene was associated with MI in Tunisian patients.

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.

Peripheral arterial disease in diabetes: is there a role for genetics?

Atherosclerotic occlusion of vessels outside of the heart is commonly referred to as peripheral arterial disease (PAD). The lower extremity is the most common site of PAD and its development is associated with the same risk factors involved in general atherosclerosis. However, there is emerging evidence that other risk factors may play a key role in the development of PAD. Over the past decade polymorphism in a number of genes has been shown to contribute to the risk of developing PAD. These genes can be classified into proartherosclerosis or proatherothrombosis based on the known gene function. Moreover, they can be categorized as "novel" polymorphism when the function of the genes is not known or when the specific gene within an associated genetic locus is not known. It is intriguing that not only are gene polymorphisms associated with PAD being identified, but more recently studies are now finding gene polymorphisms that may be important in development of this syndrome only in the contest of certain environmental factors such as diabetes. Currently how these gene-environment interactions contribute to the pathogenesis of PAD is poorly understood but will likely play a critical role in future understanding of this complex disease.

eNOS and ACE genes influence peripheral arterial disease predisposition in smokers

OBJECTIVE

Several biologic mediators and genetic predisposing factors may contribute to the development of peripheral arterial disease (PAD). The eNOS gene, encoding for endothelial nitric oxide synthase, has been proposed as a candidate gene in the predisposition to the disease. In this study, we evaluated the role of eNOS-786T>C, -894G>T and 4a/4b polymorphisms as markers of PAD per se and in the presence of the ACE D allele in patients previously investigated.

METHODS

We analyzed 281 consecutive patients (220 men, 61 women; median age, 72 years) with PAD and 562 healthy controls, comparable for sex and age.

RESULTS

eNOS-786C, but not -894T and 4a, allele frequency was significantly higher in PAD patients than in controls (P = .03). An association with the predisposition to PAD was found for the eNOS-786C allele (odds ratio [OR], 1.52; 95% confidence interval [CI], 1.11-2.09; P = .009) and the eNOS -786C/4a haplotype (OR, 1.41; 95% CI, 1.02-1.94, P = .04) at univariate analysis but not after adjustment for traditional risk factors. When smoking habit was considered, we observed that eNOS-786C/4a haplotype, but not the eNOS-786C allele, influenced PAD predisposition after adjustment for traditional risk factors in smokers (OR, 2.71; 95% CI, 1.38-5.30; P = .004). The eNOS-786C and eNOS-786C/4a haplotype did not modify the susceptibility to PAD in patients carrying the ACE D allele. Nevertheless, the presence of the eNOS-786C/4a haplotype increased PAD predisposition in smokers also carrying ACE D allele (OR, 2.71 to 3.79; P > .05 for interaction).

CONCLUSIONS

This study demonstrated an association between eNOS and ACE genes in increasing PAD susceptibility in smokers, thus providing evidence for a gene-environment interaction in modulating predisposition to the disease.

Endothelial function and endothelial nitric oxide synthase intron 4a/b polymorphism in primary hyperparathyroidism

BACKGROUND AND AIM

Patients with symptomatic primary hyperparathyroidism (pHT) have increased cardiovascular morbidity and mortality. Endothelial nitric oxide synthase (eNOS) intron 4a/b polymorphism is associated with coronary artery disease and hypertension in various populations. Our aim is to evaluate endothelial function in patients with pHT during pre-operative hypercalcemic and post-operative normocalcemic periods and to determine whether intron 4a/b polymorphism of eNOS gene influences endothelial function.

SUBJECTS AND METHODS

Forty patients with pHT (age 48.48+/-11.64 yr) were examined pre-operatively and reexamined 5.8+/-1.9 months after parathyroidectomy. Forty-three healthy subjects (age 47.13+/-8.14 yr) were served as control group. Endothelial function was determined by flow-mediated dilation of brachial artery (FMD). eNOS4a/b polymorphism was detected by polymerase chain reaction.

RESULTS

FMD was significantly lower in patients pre-operatively compared with controls (8.48+/-1.78% vs 19.49+/-2.34%, p<0.001). FMD improved significantly after parathyroidectomy (16.19+/-2.16%, p<0.001 compared with pre-operative measurements), but was still significantly lower than controls (p<0.001). The distribution of eNOS4a/b genotype frequencies was not significantly different between patients and controls. Logistic regression analysis showed that increased serum calcium (>2.47 mmol/l) and PTH concentrations (>7.75 pmol/l) were significant independent predictors of lower FMD (<16.7%). ENOS4a/b polymorphism did not enter in this model.

CONCLUSION

Impaired endothelial function in patients with pHT improves after successful parathyroid surgery. No compelling data are evident to suggest that eNOS4a/b polymorphism modifies the endothelial function in patients with pHT.

Differences in cause-of-death patterns between the native Dutch and persons of Indonesian descent in the Netherlands

We studied differences in cause-specific mortality between highly integrated first- and second-generation Indonesians and native Dutch. We used the municipal population registers and cause-of-death registry to estimate rate ratios via Poisson regression analyses. Although overall mortality levels were similar, cause-of-death patterns varied between Indonesian migrants and native Dutch; the similar levels in overall mortality coincided with the high degree of integration of Indonesians within Dutch society. The differences in cause-of-death patterns may reflect persistent influences of country of origin and migration history.

Endothelial nitric oxide synthase gene influences the risk of pre-eclampsia, the recurrence of negative pregnancy events, and the maternal-fetal flow

OBJECTIVES

Pre-eclampsia is associated with vascular endothelial dysfunction, adverse pregnancy outcome and cardiovascular disease in later life. An inadequate nitric oxide availability related to polymorphisms in the endothelial nitric oxide synthase gene (eNOS) might predispose to the disease.

METHODS

We investigated the role of eNOS T-786C, G894T and 4a4b polymorphisms in predisposing to both pre-eclampsia and the recurrence of negative pregnancy events, per se and in the presence of angiotensin-converting enzyme (ACE) DD genotype, and investigated their influence on maternal-fetal flow in 106 non-thrombophilic women with a history of pre-eclampsia, compared with 106 women with a history of normal pregnancy.

RESULTS

No association between eNOS polymorphisms and predisposition to pre-eclampsia was found; nevertheless, the contemporary presence of eNOS 894TT and -786CC genotypes represented a susceptibility factor to the disease. In 48 out of 106 women, documented complications (pre-eclampsia and fetal growth restriction) were present in the current pregnancy. The eNOS 894TT genotype influenced the risk of recurrence of negative events (odds ratio = 5.45), particularly in contemporary women homozygous for both eNOS 894TT and ACE DD genotypes (odds ratio = 11.4). Throughout the pregnancy, a progressive alteration of maternal-fetal flow indices was found in women carrying the eNOS 894TT genotype, and this effect was strengthened in women with the contemporary presence of the ACE DD genotype.

CONCLUSIONS

An original finding is the increased risk of pre-eclampsia and recurrence of pregnancy negative events, probably by modulating the maternal-fetal flow, in women homozygous for the eNOS 894T allele previously analyzed for the ACE I/D polymorphism.

Influence of endothelial nitric oxide synthase gene polymorphisms (−786T>C, 4a4b, 894G>T) in Korean patients with coronary artery disease

INTRODUCTION

Endothelium-derived nitric oxide (NO) is synthesized from l-arginine by endothelial nitric oxide synthase (eNOS) encoded by the eNOS3 gene on chromosome 7. The effects of the eNOS polymorphisms with the risk of coronary artery disease are conflicting. In this study, we investigated the association of the eNOS genotypes with coronary artery disease in Koreans.

MATERIALS AND METHODS

A case-control study was performed to evaluate the association between the eNOS -786T>C, 4a4b, or 894G>T polymorphism and coronary artery disease. 147 consecutive patients with coronary artery disease and 222 healthy controls were recruited. The genotypes of eNOS -786T>C and 894G>T polymorphisms were determined by the polymerase chain reaction-restriction fragment length polymorphism analysis. The genotypes of a 27 bp insertion/deletion in intron 4 (eNOS 4a4b) were determined by the banding pattern on gel electrophoresis.

RESULTS

The eNOS -786T>C (odds ratio [OR]; 1.61, 95% confidence interval [CI]; 0.97-2.69), 894G>T (OR; 1.12, 95% CI; 0.65-1.92) and 4a4b (OR; 1.44, 95% CI; 0.87-2.39) polymorphisms were not an independent predisposition factor to coronary artery disease. However, a subgroup analysis adjusted with various cardiovascular risk factors confirmed positive association of the -786T>C polymorphism in CAD patients with hypertension and a smoking history and also a significant association of the intron 4 genotypes with a smoking history, but no significance has been found in the eNOS polymorphisms of 894G>T upon any risk adjustment. In this study we also found that the distribution of heterozygotes (-786TC, 894GT, and 4a4b) and variant homozygotes for the -786C, 894T, and intron 4a alleles of eNOS in Koreans were significantly lower than in Caucasian populations.

CONCLUSIONS

The present study demonstrates that polymorphisms of the eNOS -786T>C and 4a4b are associated with coronary artery disease with adjustments for cardiovascular risk factors in the Koreans.

Nitric oxide and atherosclerosis: an update

Nitric oxide (NO) is a molecule that has gained recognition as a crucial modulator of vascular disease. NO has a number of intracellular effects that lead to vasorelaxation, endothelial regeneration, inhibition of leukocyte chemotaxis, and platelet adhesion. Endothelium damage induced by atherosclerosis leads to the reduction in bioactivity of endothelial NO synthase (eNOS) with subsequent impaired release of NO together with a local enhanced degradation of NO by increased generation of reactive oxygen species with subsequent cascade of oxidation-sensitive mechanisms in the arterial wall. Many commonly used vasculoprotective agents have their therapeutic actions through the production of NO. L-Arginine, the precursor of NO, has demonstrated beneficial effects in atherosclerosis and disturbed shear stress. Finally, eNOS gene polymorphism might be an additional risk factor that may contribute to predict cardiovascular events. However, further studies are needed to understand the possible clinical implications of these correlations.

Genes and atherosclerosis: at the origin of the predisposition

Atherosclerosis (ATS) is a multifactorial disease caused by the interaction of established or emerging risk factors with multiple predisposing genes that regulate ATS-related processes. This review will discuss the current knowledge concerning the potential role of the genetic variations that could promote and/or accelerate ATS, in both animal models and humans. Allelic polymorphisms or variations of distinct genes that enhance the risk of ATS frequently occur in the general population, but only adequate gene-environment interactions will lead to the disease. The main genes so far studied are involved in the regulation of processes such as endothelial function, antioxidant potential, coagulation, inflammatory response, and lipid, protein and carbohydrate metabolism. The detection of candidate genes associated with ATS could allow, in the near future, earlier interventions in genetically susceptible individuals. Further, large-scale population studies are needed to obtain more information on the specific gene-environment and drug-gene interactions capable of influencing ATS progression.

eNOS gene intron 4 a/b VNTR polymorphism is a risk factor for coronary artery disease in Southern Turkey

BACKGROUND

Nitric oxide (NO) plays a major role in the regulation of vascular tone Associations between NO genotypes, coronary artery disease (CAD) and other risk factors have been described by many authors. The aim of this study was to investigate the role of endothelial nitric oxide synthase (eNOS) gene intron 4 a/b variable number of tandem repeats (VNTR) polymorphism and other risk factors in the development of CAD in subjects living in Southern Turkey.

METHODS

Two-hundred and sixty-six patients (154 males and 112 females, aged between 30 and 80 years, mean 52.4+/-10.3) whose coronary arteries were evaluated by means of coronary angiography were enrolled in the study. Of the total, 133 had CAD (Group I) and the remaining had normal coronary arteries (Group II). The eNOS gene intron 4 a/b VNTR polymorphism was analyzed by polymerase chain reaction. The plasma lipid levels and other risk factors were also determined in all subjects.

RESULTS

The a allele frequencies and genotypes carrying a allele were significantly higher in Group I. Plasma lipids, except HDL-C, were also increased in this group. We found that hypertension (HT), diabetes mellitus (DM), male gender, age and smoking were the independent predictors of CAD.

CONCLUSION

a allele of eNOS intron 4 a/b VNTR polymorphism is not an independent predictor of CAD. eNOS intron 4 a/b polymorphism (presence of a allele) is a risk factor in addition to HT, DM, male gender, age and smoking for the development of CAD in Southern Turkey.