Consistent interethnic differences in the distribution of clinically relevant endothelial nitric oxide synthase genetic polymorphisms

The Relationship Between Sexual Dysfunctions With Disease Prolactin and Genetic Polymorphisms in Schizophrenia and Bipolar Disorder Patients Receiving Pharmacotherapy

OBJECTIVE

The aim of this study is to investigate sexual dysfunctions (SDs) and related factors in patients with schizophrenia and bipolar disorder receiving pharmacotherapy.

METHODS

This study included 111 patients. The Scale for the Assessment of Positive Symptoms (SAPS), the Scale for the Assessment of Negative Symptoms (SANS), and the Calgary Depression Scale for Schizophrenia (CDSS) were applied to the schizophrenia, and the Young Mania Rating Scale (YMRS) and Hamilton Depression Rating Scale (HAM-D) to the bipolar patient group. The sociodemographic data form and the Arizona Sexual Experiences Scale (ASEX) were applied to both of the patient groups. Blood was drawn from all patients to evaluate the indicated gene polymorphisms and evaluate prolactin levels.

RESULTS

SD was detected in 45.9% (N = 34) of the schizophrenia group, and 59.5% (N = 22) in the bipolar disorder group. SD was significantly higher in elderly patients and patients with a high smoking amount and low education levels. The eNOS -786T>C T allele frequency was found to be significantly higher in patients with SD. The logistic regression analysis determined that eNOS -786T>C CT and TT genotypes increased the risk of SD.

CONCLUSION

In this study, the high rates of SD in patients with schizophrenia and bipolar disorder, and the presence of modifiable factors that influence the presence of SD, suggest that SD should be given more attention in these patient groups. On the other hand, the high rate of SD in patients with the eNOS -786T>C T allele indicates the importance of carrying out new studies investigating the factors affecting the enzyme activity in this genotype. There is a need for more studies on eNOS genotypes and enzyme activites in this area.

A multicenter case-control study of the effect of e-nos VNTR polymorphism on upper gastrointestinal hemorrhage in NSAID users

Bleeding in non-steroidal anti-inflammatory drug (NSAID) users limited their prescription. This first multicenter full case–control study (325 cases and 744 controls), explored the association of e-NOS intron 4 variable number tandem repeat (VNTR) polymorphism with upper gastrointestinal hemorrhage (UGIH) in NSAID exposed and unexposed populations and assessed any interaction between this polymorphism and NSAIDs. NSAID users carrying e-NOS intron 4 wild type genotype or VNTR polymorphism have higher odds of UGIH than those unexposed to NSAIDs [Odds Ratio (OR): 6.62 (95% Confidence Interval (CI): 4.24, 10.36) and OR: 5.41 (95% CI 2.62, 11.51), respectively], with no effect modification from VNTR polymorphism-NSAIDs interaction [Relative Excess Risk due to Interaction (RERI): −1.35 (95% CI −5.73, 3.03); Synergism Index (S): 0.77 (95% CI 0.31, 1.94)]. Similar findings were obtained for aspirin exposure. Non-aspirin NSAID users who carry e-NOS intron 4 VNTR polymorphism have lower odds of UGIH [OR: 4.02 (95% CI 1.85, 8.75) than those users with wild type genotype [OR: 6.52 (95% CI 4.09, 10.38)]; though the interaction estimates are not statistically significant [RERI: −2.68 (95% CI −6.67, 1.31); S: 0.53 (95% CI 0.18, 1.55)]. This exploratory study suggests that the odds of UGIH in NSAID or aspirin users does not modify according to patient´s e-NOS intron 4 genotype.

Antioxidants-Related Superoxide Dismutase (SOD), Catalase (CAT), Glutathione Peroxidase (GPX), Glutathione-S-Transferase (GST), and Nitric Oxide Synthase (NOS) Gene Variants Analysis in an Obese Population: A Preliminary Case-Control Study

Oxidative stress and antioxidants play an important role in obesity etiopathology. Genetic variants, including single nucleotide polymorphisms (SNPs) of the antioxidant-related genes, may impact disease risk in several populations. This preliminary study aimed to explore the association of 12 SNPs related to superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione-S-transferase (GST), and nitric oxide synthase (NOS) genes with obesity susceptibility in a Saudi population. A total of 384 unrelated participants, including 154 (40.1%) obese individuals, were enrolled. TaqMan OpenArray Genotyping assays were used. Six SNPs were significantly more prevalent in obese cohorts: (1) GSTM1 rs1056806*C/T; (2) SOD1 rs2234694*A; (3) SOD2 rs4880*G; (4) SOD3 rs2536512*A; (5) GPX1 rs1800668*A; (6) NOS3 rs1799983*G. Four SNPs were associated with higher obesity risk under heterozygote and dominant models for GSTM1 rs1056806 (C/T), homozygote model for SOD2 rs4880 (A/G), and homozygote and recessive models for GPX1 rs1800668 (A/G). In contrast, SOD3 rs2536512 (A/G) were less likely to be obese under heterozygote and dominant models. The CGAG, CAAA, TGGG, and CGAG combined genotypes showed a higher risk of obesity. In conclusion, the present results suggest that oxidative-stress-related genetic determinants could significantly associate with obesity risk in the study population.

Acute Exercise, Plasma Nitric Oxide, and Blood Pressure in Older Adults With Different Levels of Training Status: The Influence of Polymorphisms of Endothelial Nitric Oxide Synthase

BACKGROUND

This study aimed to analyze the acute effect of physical exercise on nitric oxide concentration and blood pressure (BP) in older adults with different levels of training status (TS) and verified the influence of endothelial nitric oxide synthase polymorphisms on these variables.

METHODS

A total of 145 older adults were divided into good TS (G1) and weak TS (G2). Participants were subjected to a 40-minute treadmill walk (40%-60% of maximum oxygen consumption) with BP measurements and blood collections for plasma nitrite and oxidative stress biomarkers at pretest and posttest moments. Data were analyzed by 2-way repeated-measures with Sidak post hoc test (P < .05) and multivariate linear analysis.

RESULTS

After acute exercise, G2 showed an increase in oxidative stress biomarkers (P = .008), and both groups showed an increase in systolic BP (P < .001). Polymorphisms 894G > T and intron 4b/a had no association with nitrite and BP. However, -786T > C polymorphism showed an association with reduced systolic and diastolic BP (TT genotype) and increased diastolic BP (TC genotype). Higher TS level was also associated with lower BP.

CONCLUSION

The maintenance of good TS levels may have a protective effect on cardiovascular risks regardless of the genetic profile.

NOS3 Polymorphisms Can Influence the Effect of Multicomponent Training on Blood Pressure, Nitrite Concentration and Physical Fitness in Prehypertensive and Hypertensive Older Adult Women

Associations of endothelial nitric oxide synthase (NOS3) polymorphisms with hypertension and response to exercise training in prehypertensive and hypertensive older adult women remain unclear. This study used a multicomponent program (various capacities and motor skills) in the physical training intervention. It analyzed the influence of NOS3 polymorphisms [−786T > C, 894G > T (Glu298Asp), and intron 4b/a] on the response of blood pressure (BP), nitrite concentration, and physical fitness in older adult women. Fifty-two participants aged between 50 and 80 underwent body mass index, BP, 6-min walk, elbow flexion, and sit and stand-up tests to assess physical fitness. The intervention duration was 12 weeks, twice a week, on non-consecutive days. Each session lasted 90 min, maintaining an intensity between 13 (moderate) and 15 (intense), controlled by the Subjective Effort Perception Scale. Plasma/blood samples were collected to assess nitrite concentration and genotyping. The statistical analysis included Fisher’s exact test and linear mixed-effects models. The multicomponent training’s positive effect was observed with a similar response in both prehypertensive and hypertensive groups. However, carriers of different genotypes demonstrated different responses to training: the decreases in systolic and diastolic BP and increases in nitrite expected from the physical training were smaller in variant genotype than ancestral genotype carriers, especially in the hypertensive group. At positions −786T > C and Glu298Asp, only the ancestral genotypes showed a decrease in diastolic BP (Δ% = −8.1, and Δ% = −6.5, respectively) and an increase on nitrite (Δ% = 19.1, and Δ% = 24.1, respectively) in the hypertensive group. Our results show that the benefits of a multicomponent training intervention seem to be genotype-dependent. It should be possible to consider genetic variants when selecting an exercise treatment intervention.

Association of BglII Polymorphism in ITGA2 and (894G/T and -786T/C) Polymorphisms in eNOS Gene With Stroke Susceptibility in Tunisian Patients α2 Gene Polymorphism in α2β1 Integrin and eNOS Gene Variants and Stroke

BACKGROUND

This study investigated the association of BglII polymorphism in α2β1 integrin gene (ITGA2) and eNOS (894G/T and -786T/C) polymorphisms with ischemic stroke (IS) in Tunisian patients.

METHODS

The study comprised 210 patients with IS and 208 controls. The genotypes of the BglII polymorphism in ITGA2 and eNOS (894G/T and -786T/C) polymorphisms were determined using the PCR-RFLP. The χ² test was used and the genotype data comparison included heterozygous groups. Haplotype estimation and multiple logistic regression analysis were performed to analyze the significance of polymorphisms.

RESULTS

The genotype distribution of the BglII polymorphism was significantly different between cases and controls (p < 0.004). This polymorphism was associated with the risk of IS (OR = 3.38, p < 0.001) for the BglII(+/+) genotype. Likewise, the genotype distributions of eNOS (894G/T and -786T/C) polymorphisms were significantly different between the two groups (p < 0.005 and p < 0.01, respectively). The 894G/T polymorphism increased the risk of IS for the TT genotype (OR = 2.23, p < 0.008) and the GT genotype (OR = 1.74, p < 0.009). In addition, the -786T/C variant in the eNOS gene was a risk factor for IS for CC homozygous (OR = 2.52, p < 0.005). T-C Haplotype (OR = 3.06) from combination of the eNOS (894G/T and -786T/C) and T-C-BglII(+) haplotype (OR = 2.76) from combination of eNOS and ITGA2 polymorphisms represented high risks for IS.

CONCLUSIONS

This study suggests that the BglII variant in ITGA2 is associated with IS susceptibility. Furthermore, the 894G/T and -786T/C polymorphisms in the eNOS gene may be considered as genetic risk factors for IS in the Tunisian population.

Does eNOS derived nitric oxide protect the young from severe COVID-19 complications?

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Aging is the largest risk factors for severity and mortality in adult COVID-19.

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Severe cases of COVID-19 are related to vascular damage with evidence of direct viral infection in the endothelial cells.

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Increase risk of COVID-19 death are also highly related to disease with lower vascular Nitric Oxide (NO) level.

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Vascular viral defence by endothelial nitric oxide synthase (eNOS) derive NO may be the protecting factor for the young.

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eNOS polymorphism could potentially explain the disparity of COVID-19 mortality between Asian and non-Asian countries.

The COVID-19 pandemic poses an imminent threat to humanity, especially to the elderly. The molecular mechanisms underpinning the age-dependent disparity for disease progression is not clear. COVID-19 is both a respiratory and a vascular disease in severe patients. The damage endothelial system provides a good explanation for the various complications seen in COVID-19 patients. These observations lead us to suspect that endothelial cells are a barrier that must be breached before progression to severe disease. Endothelial intracellular defences are largely dependent of the activation of the interferon (IFN) system. Nevertheless, low type I and III IFNs are generally observed in COVID-19 patients suggesting that other intracellular viral defence systems are also activated to protect the young. Intriguingly, Nitric oxide (NO), which is the main intracellular antiviral defence, has been shown to inhibit a wide array of viruses, including SARS-CoV-1. Additionally, the increased risk of death with diseases that have underlying endothelial dysfunction suggest that endothelial NOS-derived nitric oxide could be the main defence mechanism. NO decreases dramatically in the elderly, the hyperglycaemic and the patients with low levels of vitamin D. However, eNOS derived NO occurs at low levels, unless it is during inflammation and co-stimulated by bradykinin. Regrettably, the bradykinin-induced vasodilation also progressively declines with age, thereby decreasing anti-viral NO production as well. Intriguingly, the inverse correlation between the percentage of WT eNOS haplotype and death per 100K population could potentially explain the disparity of COVID-19 mortality between Asian and non-Asian countries. These changes with age, low bradykinin and NO, may be the fundamental reasons that intracellular innate immunity declines with age leading to more severe COVID-19 complications.

Endothelial Nitric Oxide Synthase Gene Polymorphisms (- 922A > G, - 786 T > C, Intron 4 b/a VNTR and 894 G > T) and Essential Hypertension: An Association Study with Haplotypes Analysis

Endothelial Nitric Oxide Synthase (eNOS) is an indispensable regulator of blood pressure through producing Nitric Oxide (NO). There is some evidence to suggest that eNOS gene polymorphisms are associated with Essential Hypertension (EHT). In this study, the potential association between eNOS 4a/4b, A922G, G894T, T786C gene polymorphisms and EHT as individual risk factors and as haplotypes are examined in the southern population of Iran (Bandar-Abbas). In this study, 200 EHT patients and 200 normotensive subjects which were matched for age and sex were included. Genotyping was performed by either utilizing Polymerase Chain Reaction (PCR) or PCR followed by Restriction Fragment length Polymorphism (RFLP) method. Our results demonstrated statistically significant associations between T786C, G894T, and 4a/4a and EHT (p < 0.05); however, A922G had no significant association with EHT (p > 0.05). Haplotype analysis also suggested that - 786C/- 922A/4a, - 786C/- 922A/4b and - 786C/- 922G/4a haplotypes were more frequent in EHT group than control group, hypothesizing a positive association with EHT. The present study has identified that the eNOS genetic variations are associated with EHT in southern population of Iran (Bandar-Abbas). These findings also suggested that a number of haplotypes of eNOS gene may be a driving factor for EHT susceptibility in respected population.

NOS3 Gene rs1799983 and rs2070744 Polymorphisms in Patients with Unstable Angina

Acute coronary syndrome occurs when the heart muscle does not receive adequate oxygen and nutrients in a timely manner. Acute coronary syndromes are primarily due to atherosclerosis of the coronary arteries, i.e., coronary heart disease. Nitric oxide (NO) is synthesised from L-arginine in endothelial cells by the constitutive calcium-calmodulin-dependent enzyme, nitric oxide synthase (NOS), which mediates endothelium-dependent vasodilatation. Endothelial nitric oxide synthase (eNOS) is predominantly expressed in endothelial cells. Three NOS isoforms have been detected in different tissue: (1) neuronal NOS (nNOS) (NOS1), (2) eNOS (NOS2), and (3) inducible NOS (iNOS) (NOS3). These isoforms are encoded by three different genes. NOS3 is located on chromosome 7q35-36 and contains 26 exons. Previous studies have suggested that NOS3 polymorphisms may be associated with acute coronary syndromes. Therefore, the aim of the study was to examine the associations between NOS3 rs1799983 (894G/T)andrs2070744 (-786T/C) polymorphisms and unstable angina. This study included 246 patients with unstable angina, as confirmed by coronary angiography. We also included 189 healthy controls who were also assessed by this technique. There were no significant differences in genotype distributions of NOS3 rs1799983and rs2070744 polymorphisms in patients with unstable angina and healthy controls in both univariate and multivariate analyses. In patients with the NOS3 rs1799983 TT genotype, we observed a higher BMI (TT vs. GT + GG, p = 0.068), and in patients with the NOS3 rs2070744 TT genotype, we observed a higher waist circumference (TT vs. TC + CC, p = 0.023; TT vs. CC, p = 0.0053). These data suggest a lack of association between the NOS3 rs1799983andrs2070744 polymorphisms and unstable angina in our patient population. However, these polymorphisms may be associated with some obesity parameters, rs1799983 in females and rs2070744 in males.

Relation of nitric oxide synthase gene (NOS3) polymorphisms to varicocele risk and post-varicocelectomy seminal oxidative stress reduction

The pathophysiology of varicocele remains to be unknown. Several genetic factors have been implicated in varicocele etiopathogenesis. We studied the relationship between NOS3 c.894G>T, c.786T>C and 4b/a polymorphisms to varicocele risk and their prognostic value as regards improvement of the post-operative seminal parameters &/or seminal malonaldehyde levels. The three NOS3 polymorphisms were evaluated in 100 patients with varicocele and 100 healthy subjects by RT-PCR. Seminal plasma MDA level was measured pre-operatively and 3 months after varicocelectomy by the thiobarbituric acid method. The GT, TT, TC and bb genotypes of NOS3 polymorphism were more commonly observed in varicocele patients (30%, 9%, 28% and 70% respectively) compared to normal controls (12%, 0%, 10% and 50% respectively). The mean percentage of post-varicocelectomy seminal MDA reduction was highest with the GT genotype (p < .001). Genotypes GT+TT, TC and bb were associated with varicocele occurrence in our patients. The T (c.894G>T), C (c.786T>C) and b (NOS3 intron 4 VNTR) alleles were significantly associated with varicocele occurrence in our cohort of patients. We also report a better response regarding the reduction of seminal MDA after varicocelectomy with the GT and ba genotypes.

Racial disparities in cardiovascular disease risk: mechanisms of vascular dysfunction

Cardiovascular disease (CVD) accounts for a third of all deaths in the United States making it the leading cause of morbidity and mortality. Although CVD affects individuals of all races/ethnicities, the prevalence of CVD is highest in non-Hispanic black (BL) individuals relative to other populations. The mechanism(s) responsible for elevated CVD risk in the BL population remains incompletely understood. However, impaired vascular vasodilator capacity and exaggerated vascular vasoconstrictor responsiveness are likely contributing factors, both of which are present even in young, otherwise healthy BL individuals. Within this review, we highlight some historical and recent data, collected from our laboratories, of impaired vascular function, in terms of reduced vasodilator capacity and heightened vasoconstrictor responsiveness, in the peripheral and cerebral circulations in BL individuals. We provide data that such impairments may be related to elevated oxidative stress and subsequent reduction in nitric oxide bioavailability. In addition, divergent mechanisms of impaired vasodilatory capacity between BL men and women are discussed. Finally, we propose several directions where future research is needed to fill in knowledge gaps, which will allow for better understanding of the mechanisms contributing to impaired vascular function in this population. Ultimately, this information will allow for better lifestyle and therapeutic approaches to be implemented in an effort to minimize the increased CVD burden in the BL population.

Pharmacogenetic relevance of endothelial nitric oxide synthase polymorphisms and gene interactions

Endothelial nitric oxide synthase (NOS3) is a key enzyme responsible for nitric oxide (NO) generation in the vascular endothelium. Endothelial dysfunction is characterized by reduced NO production, and is a hallmark of cardiovascular diseases. Drugs with cardiovascular action may activate NOS3 and result in NO release and vasodilation. Moreover, genetic variations affect NOS3 expression and activity, and may partially explain the variability in the responses to cardiovascular drugs. We reviewed NO signaling and genetic effects on NO formation, and the effects of NOS3 polymorphisms, haplotypes and gene-gene interactions within NO signaling pathways on the responses to cardiovascular drugs. We discuss the role of rare NOS3 variants and further gene-gene interactions analysis for the development of novel therapies for cardiovascular diseases.

Association of endothelial nitric oxide synthase (eNOS) gene polymorphisms and physical fitness levels with plasma nitrite concentrations and arterial blood pressure values in older adults

Endothelial nitric oxide synthase (eNOS) gene polymorphisms are associated with reduced eNOS activity and nitric oxide (NO) production leading to an increase in blood pressure (BP). Regular exercise is the main strategy to minimize the deleterious effects of polymorphisms. However, due to the differences that physical exercise can be performed, some controversial results are found. Therefore it seems reasonable to evaluate the training status (TS). Thus, this study aimed to investigate the association of eNOS gene haplotypes and different levels of TS on nitrite concentrations (NO2-) and BP values in older adult. 424 elderly performed the following assessments: General Functional Fitness Index (GFFI) to estimate TS, systolic and diastolic blood pressure (SBP and DBP), blood collection for analysis of NO2- and g.-786T>C, intron 4b/a (VNTR) and 894G>T polymorphisms. Multivariate logistic regression showed that NO2- was influenced by GFFI and 4b/4a Intron 4. Regarding BP, GFFI influenced SBP and DBP, and just intron 4 was associated with variations in DBP. It can be observed that GFFI affected the NO2-, SBP and DBP independently of haplotypes. Therefore, maintenance of good level of TS can overcome the negative influence of genetics factors (intron 4) by increasing NO2- concentration and decreasing BP values.

Association between eNOS Gene Polymorphism (T786C and VNTR) and Sickle Cell Disease Patients in Ghana

Endothelial nitric oxide synthase (eNOS) variants have been found to be associated with several vascular disorders as well as the pathogenesis of sickle cell disease (SCD) complications such as vaso-occlusive crises (VOC). Studies on eNOS gene variants among SCD patients are rare in Ghana and several other African countries. The current study aimed to determine a possible association between variants of the eNOS gene (variable number of tandem repeats in intron 4 and T786C) in SCD complications among Ghanaian patients. This was a cross-sectional study involving 89 HbSS patients with complications and 46 HbSS patients without complications. Genomic DNA was extracted from leukocytes in the buffy coat and separated from collected whole blood samples of the study participants. PCR amplification, followed by restriction fragment length polymorphism (RFLP) was used to genotype T786C (rs2070744) variants. Variable number of tandem repeats (VNTR) in intron 4 was genotyped by PCR and direct electrophoresis. There was a significant difference in the genotype frequency of the T786C variant between HbSS patients with complications and those without complications (p = 0.0165). However, there was no significant difference in the VNTR intron 4 variant of the eNOS gene between patients with complications and those without complications (p > 0.05). The study shows an association between the eNOS gene variant (T786C) and complications in SCD.

Effect of Multicomponent Training on Blood Pressure, Nitric Oxide, Redox Status, and Physical Fitness in Older Adult Women: Influence of Endothelial Nitric Oxide Synthase (NOS3) Haplotypes

The purpose of this study was to verify the influence of the genotype or haplotype (interaction) of the NOS3 polymorphisms [-786T>C, 894G>T (Glu298Asp), and intron 4b/a] on the response to multicomponent training (various capacities and motor skills) on blood pressure (BP), nitrite concentration, redox status, and physical fitness in older adult women. The sample consisted of 52 participants, who underwent body mass index and BP assessments. Physical fitness was evaluated by six-minute walk, elbow flexion, and sit and stand up tests. Plasma/blood samples were used to evaluate redox status, nitrite concentration, and genotyping. Associations were observed between isolated polymorphisms and the response of decreased systolic and diastolic BP and increased nitrite concentration and antioxidant activity. In the haplotype analysis, the group composed of ancestral alleles (H1) was the only one to present improvement in all variables studied (decrease in systolic and diastolic BP, improvement in nitrite concentration, redox status, and physical fitness), while the group composed of variant alleles (H8) only demonstrated improvement in some variables of redox status and physical fitness. These findings suggest that NOS3 polymorphisms and physical training are important interacting variables to consider in evaluating redox status, nitric oxide availability and production, and BP control.

Combination of Hydralazine and Isosorbide-Dinitrate in the Treatment of Patients with Heart Failure with Reduced Ejection Fraction

The use of direct acting vasodilators (the combination of hydralazine and isosorbide dinitrate -Hy+ISDN-) in heart failure with reduced ejection fraction (HFrEF) is supported by evidence, but rarely used.However, treatment with Hy+ISDN is guideline-recommended for HFrEF patients who cannot receive either angiotensin-converting enzyme inhibitors or angiotensin receptor blockers due to intolerance or contraindication, and in self-identified African-American HFrEF patients who are symptomatic despite optimal neurohumoral therapy.The Hy+ISDN combination has arterial and venous vasodilating properties. It can decrease preload and afterload, decrease left ventricular end-diastolic diameter and the volume of mitral regurgitation, reduce left atrial and left ventricular wall tension, decrease pulmonary artery pressure and pulmonary arterial wedge pressure, increase stroke volume, and improve left ventricular ejection fraction, as well as induce left ventricular reverse remodelling. Furthermore, Hy+ISDN combination has antioxidant property, it affects endothelial dysfunction beneficially and improves NO bioavailability. Because of these benefits, this combination can improve the signs and symptoms of heart failure, exercise capacity and quality of life, and, most importantly, reduce morbidity and mortality in well-defined subgroups of HFrEF patients.Accordingly, this therapeutic option can in many cases play an essential role in the treatment of HFrEF.

Polymorphism of the endothelin-1 gene (rs5370) is a potential contributor to sickle cell disease pathophysiology

Sickle cell disease has been shown to demonstrate extensive variability in disease severity among and between individuals, the variability highlighted by differing genetic haplotypes. Despite the abundance of reports of functional significance due to polymorphisms of endothelial nitric oxide synthase (eNOS) and endothelin-1 (ET-1) genes, the role of these polymorphisms in mediating sickle cell disease pathophysiology among African Americans is presently unclear. To deconvolute their potential significance among African Americans with sickle cell disease, we examined the genetic diversity and haplotype frequency of eNOS and ET-1 polymorphisms in disease (n = 331) and control (n = 379) groups, with a polymerase-chain reaction restriction fragment length polymorphism assay. We report that genotypic and allelic frequencies of eNOS variants are not significantly different between groups. eNOS homozygote mutants, which had been shown to have clinical significance elsewhere, showed no statistical significance in our study. On the other hand, and contrary to previous report among Africans with sickle cell disease, the endothelin-1 homozygous mutant variant showed significant difference in genotypic (p = 2.84E-12) and allelic frequencies (p = 2.20E-16) between groups. The most common haplotype is the combination of T786C homozygote wild-type variant with homozygote mutant variants of G5665T (ET-1) and Glu298Asp (eNOS). These results show that endothelin-1 (rs5370) polymorphism, rather than endothelial nitric oxide synthase polymorphism might play a significant role in disease severity or individual clinical outcomes among African Americans with sickle cell disease. This would have profound implications for designing and/or advancing personalized care for sickle cell patients and relieving disease complications.

Association of Cholesteryl Ester Transfer Protein and Endothelial Nitric Oxide Synthase Gene Polymorphisms With Coronary Artery Disease in the Multi-Ethnic Malaysian Population

Genetic variants of cholesteryl ester transfer protein (CETP) and endothelial nitric oxide synthase (eNOS) influence high-density lipoprotein cholesterol (HDL-C) metabolism and nitric oxide (NO) synthesis, respectively, and might increase the risk of coronary artery disease (CAD). This study is to investigate the relationship between genetic polymorphisms and the risk of CAD and to evaluate their potential interactions. A total of 237 patients with CAD and 101 controls were genotyped. The association of the polymorphism with the risk of CAD varied among the ethnic groups. Moreover, the concomitant presence of both CETP B1 and eNOS 4a alleles significantly increased the risk of CAD in the Malay group (OR = 33.8, P < .001) and the Indian group (OR = 10.9, P = .031) but not in the Chinese group. This study has identified a novel ethnic-specific gene–gene interaction and suggested that the combination of CETP B1 allele and eNOS 4a allele significantly increases the risk of CAD in Malays and Indians.

New Findings in eNOS gene and Thalidomide Embryopathy Suggest pre-transcriptional effect variants as susceptibility factors

Antiangiogenic properties of thalidomide have created an interest in the use of the drug in treatment of cancer. However, thalidomide is responsible for thalidomide embryopathy (TE). A lack of knowledge regarding the mechanisms of thalidomide teratogenesis acts as a barrier in the aim to synthesize a safer analogue of thalidomide. Recently, our group detected a higher frequency of alleles that impair the pro-angiogenic mechanisms of endothelial nitric oxide synthase (eNOS), coded by the NOS3 gene. In this study we evaluated variable number tandem repeats (VNTR) functional polymorphism in intron 4 of NOS3 in individuals with TE (38) and Brazilians without congenital anomalies (136). Haplotypes were estimated for this VNTR with previously analyzed polymorphisms, rs2070744 (−786C > T) and rs1799983 (894T > G), in promoter region and exon 7, respectively. Haplotypic distribution was different between the groups (p = 0.007). Alleles −786C (rs2070744) and 4b (VNTR), associated with decreased NOS3 expression, presented in higher frequency in TE individuals (p = 0.018; OR = 2.57; IC = 1.2–5.8). This association was not identified with polymorphism 894T > G (p = 0.079), which influences eNOS enzymatic activity. These results suggest variants in NOS3, with pre-transcriptional effects as susceptibility factors, influencing the risk TE development. This finding generates insight for a new approach to research that pursues a safer analogue.

Sport physiology, dopamine and nitric oxide - Some speculations and hypothesis generation

Elite Spanish professional soccer players surprisingly showed a preponderance of an allele coding for nitric oxide synthase (NOS) that resulted in lower nitric oxide (NO) compared with Spanish endurance and power athletes and sedentary men. The present paper attempts a speculative explanation. Soccer is an "externally-paced" (EP) sport and team work dependent, requiring "executive function skills". We accept that time interval estimation skill is, in part, also an executive skill. Dopamine (DA) is prominent among the neurotransmitters with a role in such skills. Polymorphisms affecting dopamine (especially DRD2/ANKK1-Taq1a which leads to lower density of dopamine D2 receptors in the striatum, leading to increased striatal dopamine synthesis) and COMT val 158 met (which prolongs the action of dopamine in the cortex) feature both in the time interval estimation and the executive skills literatures. Our paper may be a pioneering attempt to stimulate empirical efforts to show how genotypes among soccer players may be connected via neurotransmitters to certain cognitive abilities that predict sporting success, perhaps also in some other externally-paced team sports. Graphing DA levels against time interval estimation accuracy and also against certain executive skills reveals an inverted-U relationship. A pathway from DA, via endogenous morphine and mu3 receptors on endothelia, to the generation of NO in tiny quantities has been demonstrated. Exercise up-regulates DA and this pathway. With somewhat excessive exercise, negative feedback from NO down-regulates DA, hypothetically keeping it near the peak of the inverted-U. Other research, not yet done on higher animals or humans, shows NO "fine-tuning" movement. We speculate that Caucasian men, playing soccer recreationally, would exemplify the above pattern and their nitric oxide synthase (NOS) would reflect the norm of their community, whereas professional players of soccer and perhaps other EP sports, with DA boosted by very frequent and intense practice and extra stress from public scrutiny, would potentially have their negative feedback system overwhelmed, were it not that many of them carry the C allele of the NOS3-786T/C polymorphism. Then, even very high DA would not result in so much NO as to shut the system down. We add some evolutionary speculations.

Endothelial nitric oxide synthase: From biochemistry and gene structure to clinical implications of NOS3 polymorphisms

Nitric oxide (NO) is an important vasodilator with a well-established role in cardiovascular homeostasis. While mediator is synthesized from L-arginine by neuronal, endothelial, and inducible nitric oxide synthases (NOS1,NOS3 and NOS2 respectively), NOS3 is the most important isoform for NO formation in the cardiovascular system. NOS3 is a dimeric enzyme whose expression and activity are regulated at transcriptional, posttranscriptional,and posttranslational levels. The NOS3 gene, which encodes NOS3, exhibits a number of polymorphic sites including single nucleotide polymorphisms (SNPs), variable number of tandem repeats (VNTRs), microsatellites, and insertions/deletions. Some NOS3 polymorphisms show functional effects on NOS3 expression or activity, thereby affecting NO formation. Interestingly, many studies have evaluated the effects of functional NOS3 polymorphisms on disease susceptibility and drug responses. Moreover, some studies have investigated how NOS3 haplotypes may impact endogenous NO formation and disease susceptibility. In this article,we carried out a comprehensive review to provide a basic understanding of biochemical mechanisms involved in NOS3 regulation and how genetic variations in NOS3 may translate into relevant clinical and pharmacogenetic implications.

Association study of NOS3 gene polymorphisms and hypertension in the Han Chinese population

BACKGROUND

Recent studies have reported that NOS3 plays an important role in cardiovascular pathology, whereas the association of NOS3 and hypertension (HT) has been controversial between African Americans and European whites. Here, we aimed to further investigate the genetic effect of unexplored loci at NOS3 on the susceptibility of HT in the Han Chinese population.

METHODS AND RESULTS

The association of three polymorphisms; rs4496877, rs1808593 and rs3918186 to HT was tested in a case control study that included 2012 HT cases and 2210 controls. Association analysis showed that there was no significant association between rs4496877, rs1808593 and rs3918186 of NOS3 and HT in the whole study population. Stratification analysis indicated that rs3918186 was significantly associated with HT in the ≥55-year-old population (OR = 1.245, 95% CI = 1.010-1.534, P = 0.04). The rs4496877 and rs1808593 were significantly associated with HT in the male population (P = 0.015) and <55-year-old population (P = 0.025), respectively (OR = 3.254, 95% CI = 1.257-8.425 and OR = 1.683, 95% CI = 1.066-2.657, respectively). Quantitative trait analysis showed that there were significant differences in systolic blood pressure (SBP) among the genotypes (AA, AT and TT) of rs3918186 in the non-intervention populations (P = 0.016). GMDR analysis showed that drinking and rs3918186 had significant interaction effects for risk of HT.

CONCLUSIONS

The findings of this study indicated that the rs4496877, rs1808593 and rs3918186 polymorphisms of NOS3 contribute to the genetic susceptibility of HT and that rs3918186 was associated with SBP in the Chinese population. Age and gender might modify the genetic effect of NOS3 on HT, and drinking significantly interacts with rs3918186.

Outcome after BCG treatment for urinary bladder cancer may be influenced by polymorphisms in the NOS2 and NOS3 genes

Purpose

Bacillus Calmette-Guérin (BCG)-treatment is an established treatment for bladder cancer, but its mechanisms of action are not fully understood. High-risk non-muscle invasive bladder-cancer (NMIBC)-patients failing to respond to BCG-treatment have worse prognosis than those undergoing immediate radical cystectomy and identification of patients at risk for BCG-failure is of high priority. Several studies indicate a role for nitric oxide (NO) in the cytotoxic effect that BCG exerts on bladder cancer cells. In this study we investigated whether NO-synthase (NOS)-gene polymorphisms, NOS2-promoter microsatellite (CCTTT)n, and the NOS3-polymorphisms-786T>C (rs2070744) and Glu298Asp (rs1799983), can serve as possible molecular markers for outcome after BCG-treatment for NMIBC.

Materials and methods

All NMIBC-patients from a well-characterized population based cohort were analyzed (n=88). Polymorphism data were combined with information from 15-years of clinical follow-up. The effect of BCG-treatment on cancer-specific death (CSD), recurrence and progression in patients with varying NOS-genotypes were studied using Cox proportional hazard-models and log rank tests.

Results

BCG-treatment resulted in significantly better survival in patients without (Log rank: p=0.006; HR: 0.12, p=0.048), but not in patients with a long version ((CCTTT)n ≧13 repeats) of the NOS2-promoter microsatellite. The NOS3-rs2070744(TT) and rs1799983(GG)-genotypes showed decreased risk for CSD (Log rank(TT): p=0.001; Log rank(GG): p=0.010, HR(GG): 0.16, p=0.030) and progression (Log rank(TT): p<0.001, HR(TT): 0.05, p=0.005; Log rank(GG): p<0.001, HR(GG): 0.10, p=0.003) after BCG-therapy compared to the other genotypes. There was also a reduction in recurrence in BCG-treated patients that was mostly genotype independent. Analysis of combined genotypes identified a subgroup of 30% of the BCG-treated patients that did not benefit from BCG-treatment.

Conclusions

Our results suggest that the investigated polymorphisms influence patient response to BCG-treatment and thus may serve as possible markers for identification of BCG-failures.

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30% of BCG treated bladder cancer (NMIBC)-patients do not respond to BCG-treatment.

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We need to identify BCG failures before the BCG-treatment is given.

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Altered NOS2 and NOS3 gene activity may be associated with BCG treatment outcome.

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NOS-polymorphisms are possible BCG-failure biomarkers in bladder cancer patients.

Mitochondrial and genomic ancestry are associated with etiology of heart failure in Brazilian patients

There is a high prevalence of heart failure (HF) in the general population, but it is more common in black people. We evaluated the association between genomic ancestry and mitochondrial haplogroups (mt-haplogroups) with HF etiology in 503 Brazilian patients. We elicited Mt-haplogroups by analyzing the control region of mitochondrial DNA, and genomic ancestry, by using 48 autosomal insertion-deletion ancestry informative markers. Hypertensive (28.6%, n=144) and ischemic (28.4%, n=143) etiologies of HF were the most prevalent herein. Our results showed that 233 individuals (46.3%) presented African mitochondrial (mt)-haplogroups, and the major contribution in the genomic ancestry analysis was the European ancestry (57.5% (±22.1%)). African mt-haplogroups were positively associated with a diagnosis of hypertensive cardiomyopathy (odds ratio, OR 1.55, confidence interval, CI 95% 1.04-2.44, P=0.04) when compared with European mt-haplogroups. Regarding the genomic ancestry, the African ancestry variant had higher risks (OR 7.84, 95% CI 2.81-21.91, P<0.001), whereas the European ancestry variant had lower risks (OR 0.14, 95% CI 0.04-5.00, P<0.001) for developing the hypertensive etiology. In addition, European ancestry showed an OR of 4.05 (CI 95% 1.53-10.74, P=0.005), whereas African ancestry showed an OR of 0.17 (CI 95% 0.06-0.48, P=0.001) for developing ischemic etiology. In conclusion, this study supports the importance of using ancestry informative markers and mitochondrial DNA to study the genetics of complex diseases in admixed populations to improve the management, treatment and prevention of these illnesses. Therefore, the ancestry informative markers and mt-haplogroups could provide new biomarkers to be associated with HF etiologies and be used as a premise for more specific management.

Endothelial nitric oxide synthase polymorphism and prognosis in systolic heart failure patients

BACKGROUND

The endothelial nitric oxide synthase (eNOS) gene single nucleotide polymorphism G894T is associated with thrombotic vascular diseases. However, its functional significance is controversial and data are scarce concerning its influence in heart failure (HF).

METHODS

We studied 215 patients with chronic systolic HF. DNA was analyzed for eNOS gene G894T polymorphism using PCR and DNA sequencing. Evaluation of clinical characteristics and analysis of factors associated with 2-year mortality were performed for the homozygous G-allele G894T variant (GG), relative to the TT and GT variants.

RESULTS

The genotype distributions of eNOS G894T alleles were: GG 135 patients (63%) and TT/GT 80 (37%). Two-year mortality was significantly higher in the GG variant (48%) than the combined TT/GT group (32%). The usage of nitrates was associated with increased 2-year mortality (HR 2.0, 95% CI 1.28-3.17; p = 0.003), which was most significant in the GG group treated with nitrates (73.5%) in comparison to the TT/GT group not treated with nitrates (34%); HR 2.75, 95% CI 1.57-4.79, P < 0.001.

CONCLUSIONS

Homozygosity for the G allele of the eNOS G894T polymorphism was associated with worse survival in systolic HF patients, especially in those treated with nitrates. ENOS polymorphism may result in different mechanistic interactions in HF than in thrombotic vascular diseases, suggesting that overexpression of NO may be associated with deleterious effects in systolic HF.

Associations of the eNOS G894T gene polymorphism with target organ damage in children with newly diagnosed primary hypertension

BACKGROUND

The endothelial nitric oxide synthase (eNOS) G894T gene polymorphism is associated with the risk of primary hypertension (PH) and vascular complications in adults with PH.

METHODS

We explored the associations of the G894T polymorphism with 24-h ambulatory blood pressure, left ventricular mass (LVM), carotid intima media thickness (cIMT), urinary albumin excretion, oxidative stress and inflammatory parameters in 126 children with newly diagnosed PH and in 83 healthy children.

RESULTS

Among the 126 children with PH 92 (73%) had ambulatory hypertension and 34 (27%) had severe ambulatory hypertension. Left ventricular hypertrophy (LVH) was detected in 39 (31%) patients, cIMT of >2 standard deviation scores in 21 (16.6%) patients, albuminuria of >30 mg/24 h in 18 (14.3%) patients and metabolic syndrome (MS) in 22 (17.5%) patients. The frequency of the T allele was 52.4% in the PH group and 54.2% in the control group (not significant), and in both groups the frequency of the T allele was consistent with the Hardy-Weinberg equilibrium. Compared with G allele carriers, hypertensive T allele carriers had increased cIMT (p < 0.05) and more severe albuminuria (not significant, p = 0.1); there was no difference between the groups in hypertension severity and LVM. T and G allele distribution did not differ between patients with and without metabolic syndrome. No significant correlations between the assessed parameters and the eNOS G894T gene polymorphism were found in the controls, although T allele carriers tended to have an increased cIMT (p = 0.09).

CONCLUSION

The eNOS T allele is not more prevalent among hypertensive children than among healthy ones, but it is associated with early vascular damage in children with PH, independent of metabolic abnormalities. No associations between the eNOS G894T polymorphism and metabolic abnormalities were found.

Race, common genetic variation, and therapeutic response disparities in heart failure

Because of its comparatively recent evolution, Homo sapiens exhibit relatively little within-species genomic diversity. However, because of genome size, a proportionately small amount of variation creates ample opportunities for both rare mutations that may cause disease as well as more common genetic variations that may be important in disease modification or pharmacogenetics. Primarily because of the East African origin of modern humans, individuals of African ancestry (AA) exhibit greater degrees of genetic diversity than more recently established populations, such as those of European ancestry (EA) or Asian ancestry. Those population effects extend to differences in frequency of common gene variants that may be important in heart failure natural history or therapy. For cell-signaling mechanisms important in heart failure, we review and present new data for genetic variation between AA and EA populations. Data indicate that: 1) neurohormonal signaling mechanisms frequently (16 of the 19 investigated polymorphisms) exhibit racial differences in the allele frequencies of variants comprising key constituents; 2) some of these differences in allele frequency may differentially affect the natural history of heart failure in AA compared with EA individuals; and 3) in many cases, these differences likely play a role in observed racial differences in drug or device response.

Influence of training status and eNOS haplotypes on plasma nitrite concentrations in normotensive older adults: a hypothesis-generating study

The purpose of this study was to evaluate the relationship between 3 eNOS gene polymorphisms and training status (TS) in affecting plasma nitrite concentration (NO2) in normotensive adults over 50 years old. Resting blood pressure (BP) was measured in all participants (n = 101). Plasma was taken to analyze: lipid profile, nitrite concentration (NO2) and lipid peroxide levels (T-BARS). Also, genomic DNA was extracted from plasma for genotyping NOS3 polymorphisms (-786T>C; 894G>T; and VNTR in intron 4). TS was determined by one-mile walk test and Functional Fitness Test Battery from AAHPERD (TS1-regular TS; TS2-good TS; and TS3-very good TS). BP was not influenced by TS, but NO2 was 15% higher in TS3 (123 ± 27 nM) compared to TS-2 (106 ± 22 nM). No differences were found in plasma NO2 in the haplotype analyses. However, the presence of the C allele (T-786C) and ASP allele (Glu298Asp) was found to enhance the correlation between TS and NO2 levels (r = 0.492 in C/4b/ASP haplotype and r = 0.855 in C/4a/ASP haplotype). This study thus identifies NOS3 polymorphism-dependent sensitivity to the effects of physical training on plasma NO2. Maintenance of good levels of training status, in carriers of C allele for T-786C polymorphism, combined with ASP allele for Glu298Asp polymorphism, may result in an increase in the NO2 plasma concentrations, which may reflect improved NO bioavailability in older adult normotensive individuals.

Effects of polymorphisms in endothelial nitric oxide synthase and folate metabolizing genes on the concentration of serum nitrate, folate, and plasma total homocysteine after folic acid supplementation: a double-blind crossover study

OBJECTIVES

A number of studies have explored the effects of dietary nitrate on human health. Nitrate in the blood can be recycled to nitric oxide, which is an essential mediator involved in many important biochemical mechanisms. Nitric oxide is also formed in the body from l-arginine by nitric oxide synthase. The aim of this study was to investigate whether genetic polymorphisms in endothelial nitric oxide synthase (eNOS) and genes involved in folate metabolism affect the concentration of serum nitrate, serum folate, and plasma total homocysteine in healthy individuals after folic acid supplementation.

METHODS

In a randomized double-blind, crossover study, participants were given either folic acid 800 μg/d (n = 52) or placebo (n = 51) for 2 wk. Wash-out period was 2 wk. Fasting blood samples were collected, DNA was extracted by salting-out method and the polymorphisms in eNOS synthase and folate genes were genotyped by polymerase chain reaction methods. Measurement of serum nitrate and plasma total homocysteine (p-tHcy) concentration was done by high-performance liquid chromatography.

RESULTS

The concentration of serum nitrate did not change in individuals after folic acid supplements (trial 1); however, the concentration of serum nitrate increased in the same individuals after placebo (P = 0.01) (trial 2). The individuals with three polymorphisms in eNOS gene had increased concentration of serum folate and decreased concentration of p-tHcy after folic acid supplementation. Among the seven polymorphisms tested in folate metabolizing genes, serum nitrate concentration was significantly decreased only in DHFR del 19 gene variant. A significant difference in the concentration of serum nitrate was detected among individuals with MTHFR C > T677 polymorphisms.

CONCLUSIONS

Polymorphisms in eNOS and folate genes affect the concentration of serum folate and p-tHcy but do not have any effect on the concentration of NO3 in healthy individuals after folic acid supplementation.

Polymorphisms in endothelial nitric oxide synthase gene in early and late severe preeclampsia

Preeclampsia (PE) is characterized by hypertension and proteinuria, occurring after the 20th week of pregnancy in women who have had no previous symptoms. The disease progresses with generalized vasoconstriction and endothelial dysfunction. Clinically, it is important to diagnose the severe form of the disease (sPE), in which blood pressure and proteinuria are much higher. Recently, the gestational age (GA) of the onset of PE has led to the classification of this disease as early (GA <34 weeks) and late (GA ≥34 weeks). Several genetic polymorphisms affecting endothelial nitric oxide synthase (eNOS) levels or function were described, including G894T (Glu298Asp), VNTR b/a (variable-number 27-bp tandem repeat) and T-786C (promoter) polymorphisms. Thus, the aim of this study was to compare the distribution of G894T, VNTR b/a and T-786C polymorphisms and their haplotypes in Brazilian early and late sPE, as well as in normotensive pregnant. A total of 201 women were evaluated, 53 with early sPE, 45 with late sPE and 103 as normotensive pregnant women. The frequency of 894T allele was higher in late sPE vs normotensive pregnant, and 894TT genotype was higher in late sPE vs early sPE and normotensive pregnant. For VNTR b/a polymorphism, higher frequencies of aa genotype and a allele were observed in early sPE vs late sPE and normotensive pregnant. Besides, the frequency of haplotype T-b-C was higher in late sPE vs early sPE and normotensive pregnant. Considering the results found for eNOS polymorphisms, it is possible to suggest that the functional alterations induced by these two polymorphisms may influence the time of severe PE onset, although both alterations are putatively associated with low NO bioavailability. However, other studies are necessary to validate these findings and clarify this issue.

Endothelial nitric oxide synthase gene polymorphisms and the risk of hypertension in an Indian population

Genetic variants of eNOS gene play a significant role in the pathogenesis of hypertension. Many environmental factors have, also, been implicated in the aetiology of hypertension. We carried out an age-matched case-control study among adults. Hypertension was defined according to JNC-VII criteria and eNOS gene polymorphisms were determined by PCR and PCR followed by PCR-RFLP. eNOS intron 4 aa genotype (adjusted OR 6.81; 95% CI 2.29–20.25) and eNOS 894TT genotype (adjusted OR 7.84; 95% CI 2.57–23.96) were associated with the risk of hypertension. Tobacco users (either smoking/chewing or both) with eNOS intron 4 aa genotype (OR 14.00: 95% CI 1.20–163.37), eNOS 894GG genotype (OR 5.56: 95% CI 3.72–8.31), and eNOS T-786C CC genotype (OR 9.00: 95% CI 1.14–71.04) were at an increased risk of hypertension. Similarly a significant gene-environment interaction was observed between individuals consuming alcohol with eNOS intron 4 aa genotype (OR 12.00: 95% CI 1.20–143.73) and eNOS 894GG genotype (OR 1.95: 95% CI 1.35–2.81). The present study identified few susceptible genotypes of the eNOS gene with the risk of hypertension. Moreover, the interactive effects between the environmental factors and the risk of hypertension were dependent on the eNOS genotypes.

The effects of endothelial nitric oxide synthase tagSNPs on nitrite levels and risk of hypertension and obesity in children and adolescents

Obesity and the nitric oxide synthase 3 (NOS3) gene polymorphisms are associated with nitrite levels and hypertension. However, no study has tested the hypothesis that NOS3 tagSNPs rs3918226, rs3918188, rs743506 and rs7830 affect nitrite levels and are associated with hypertension in childhood obesity. We investigated the association of these NOS3 tagSNPs and the haplotypes formed by them with hypertension and with nitrite levels in children and adolescents with obesity and with obesity plus hypertension. We studied 355 subjects: 174 healthy (controls), 109 normotensive obese, and 72 obese children and adolescents with obesity plus hypertension. Genotypes were determined by Taqman allele discrimination assay and real-time PCR. We compared the distribution of NOS3 tagSNP genotypes, alleles and haplotypes in the three groups of subjects. Nitrite levels were determined by ozone-based chemiluminescence. Nitrite levels were affected by the rs3918226 polymorphism (P<0.05) but not by NOS3 haplotypes. There was no association between the tagSNPs studied and hypertension in children and adolescents. Our findings show that the NOS3 tagSNP rs3918226 is associated with NO production in children and adolescents, and suggest that this polymorphism may have an impact on cardiovascular health. Further studies are needed to better clarify the effects of this polymorphism on cardiovascular risk.

Endothelin-1 but not Endothelial Nitric Oxide Synthase Gene Polymorphism is Associated with Sickle Cell Disease in Africa

Sickle cell disease shows marked variability in severity and pathophysiology among individuals, probably linked to differential expression of various adhesion molecules. In this study, we investigated the differential distribution, genomic diversity and haplotype frequency of endothelial nitric oxide synthase (eNOS) and endothelin-1 (ET-1) polymorphisms, recently implicated as important in modification of disease severity. One hundred and forty five sickle cell disease patients (HbSS) and 244 adult and pediatric controls, without sickle cell disease (HbAA), were recruited from Mali. Genotypic analysis of the functionally significant eNOS variants (T786C, G894T and intron 4) and endothelin-1 (G5665T) was carried out with a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Our results show that the wild type alleles are the most frequent for all eNOS variants between cases and controls. Allelic and genotypic frequencies of eNOS polymorphic groups are not significantly different between cases and controls (P > 0.05). In addition, there is no association between eNOS variants and sickle cell disease, contrary to published reports. On the other hand, we report that endothelin-1 (G5665T) mutant variant had the lowest allelic frequency, and is significantly associated with sickle cell disease in Africa (P < 0.05). Similarly, haplotype frequencies were the same between cases and controls, except for the haplotype combining all mutant variants (T, C, 4a; P = 0.01). eNOS polymorphic variants are less frequent, with no significance with sickle cell disease in Africa. On the other hand, endothelin-1 is associated with sickle cell disease, and has the capacity to redefine pathophysiology and possibly serve as modulator of disease phenotype.

The presence of the NOS3 gene polymorphism for intron 4 mitigates the beneficial effects of exercise training on ambulatory blood pressure monitoring in adults

The number of studies that have evaluated exercise training (ET) and nitric oxide synthase (NOS)3 gene polymorphisms is scarce. The present study was designed to evaluate the relationship between exercise training and NOS3 polymorphisms at -786T>C, 894G>T, and intron 4b/a on blood pressure (BP) using 24-h ambulatory BP monitoring (ABPM), nitrate/nitrite levels (NOx), and redox state. Eighty-six volunteers (51 ± 0.6 yr old) were genotyped into nonpolymorphic and polymorphic groups for each of the three positions of NOS3 polymorphisms. Auscultatory BP, ABPM, SOD activity, catalase activity, NOx levels, and malondialdehyde levels were measured. DNA was extracted from leukocytes, and PCR followed by sequencing was applied for genotype analysis. Aerobic ET consisted of 24 sessions for 3 days/wk for 40 min at moderate intensity. This study was performed in a double-blind and crossover format. ET was effective in lowering office BP (systolic BP: 3.2% and diastolic BP: 3%) as well as ABPM (systolic BP: 2% and diastolic BP: 1.3%). Increased SOD and catalase activity (42.6% and 15.1%, respectively) were also observed. The NOS3 polymorphism for intron 4 mitigated the beneficial effect of ET for systolic BP (nonpolymorphic group: -3.0% and polymorphic group: -0.6%) and diastolic BP (nonpolymorphic group: -3.2% and polymorphic group: -0.5%), but it was not associated with NOx level and redox state. Paradoxical responses were found for positions T786-C and G894T for the NOS3 gene. Consistently, the presence of the polymorphism for intron 4 blunted the beneficial effects of ET in middle-aged adults. Possibly, this effect might be as consequence of intron 4 acting as a short intronic repeat RNA controlling endothelial NOS activity epigenetically.

The role and importance of gene polymorphisms in the development of atherosclerosis

The development of atherosclerosis is a multifactorial process. The purpose of the study was to examine three genetic polymorphisms playing a role in the metabolic processes underlying the disease. We compared the data of 348 atherosclerotic non-diabetic patients with 260 atherosclerotic diabetic patients and 384 healthy controls. We analyzed the prevalence of myocardial infarction and stroke in three different groups of patients carrying different polymorphisms. It was proved that if the mutant TT eNOS Glu298ASP variant is present, a significantly higher number of myocardial infarctions can be observed than in patients carrying heterozygote GT or normal GG genotype. We proved that in the case of MTHFR 677CT heterozygote variants, the occurrence of myocardial infarction is significantly higher and the difference is also significant in case of the 677TT homozygote variant. It was verified that among patients with the mutant TNF-α AA genotype the occurrence of cardiovascular events was significantly higher. Screening the genetically high risk groups on the long run should be considered as an early detection opportunity that may give better chances for prevention and treatment. Understanding the inflammatory mechanisms of the atherosclerosis may give new therapeutical targets to pharmacologists.

Extensive ethnogenomic diversity of endothelial nitric oxide synthase (eNOS) polymorphisms

Nitric oxide (NO) is highly reactive, produced in endothelial cells by endothelial NO synthase (eNOS) and has been implicated in sickle cell pathophysiology. We evaluated the distribution of functionally significant eNOS variants (the T786C variant in the promoter region, the Glu298Asp variant in exon 7, and the variable number of tandem repeats (VNTR) in intron 4) in Africans, African Americans and Caucasians. The C-786 variant was more common in Caucasians than in Africans and African Americans. Consistent with other findings, the Asp-298 variant had the highest frequency in Caucasians followed by African Americans, but was completely absent in Africans. The very rare intron 4 allele, eNOS 4c, was found in some Africans and African Americans, but not in Caucasians. eNOS 4d allele was present in 2 Africans. These findings suggest a consistent and widespread genomic diversity in the distribution of eNOS variants in Africans, comparative to African Americans and Caucasians.

Endothelial nitric oxide gene haplotype reduces the effect of a single bout of exercise on the vascular reactivity in healthy subjects

Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene reduce shear stress-induced nitric oxide production. Thus, we investigated the individual and combined impact of 3 variants in the eNOS gene (-786T>C, intron 4b4a, and 894G>T) on vascular reactivity before and after exercise. Sedentary, healthy subjects were studied (105 women/26 men, age 32 ± 1 years [mean ± standard error of the mean]). Genotypes were determined by polymerase chain reaction restriction fragment length polymorphism, and haplotypes were determined by a Bayesian-based algorithm. Vascular reactivity was evaluated by the percentage of change in forearm vascular conductance provoked by 5 minutes of circulatory occlusion before (baseline) and 10, 60, and 120 minutes after a maximal cardiopulmonary exercise test. Vascular reactivity increased 10 minutes after exercise in the entire sample (baseline: 218 ± 11% vs 10 minutes: 284 ± 15%, P < 0.001), remained increased at 60 minutes (239 ± 12%, P = 0.02 vs baseline), and returned to baseline at 120 minutes (210 ± 10%, P = 0.83 vs baseline). Genotype analysis showed that subjects with the 894G>T polymorphism had lower vascular reactivity than wild counterparts (group effect, P = 0.05). Furthermore, subjects with haplotype 2 (H2), containing the -786T>C and 894G>T polymorphisms, had lower vascular reactivity than wild counterparts (haplotype 1 [H1]) (group effect, P = 0.05), whereas subjects with haplotype 4 (H4), containing only the 894G>T polymorphism, had vascular reactivity similar to that of wild counterparts (H1) (group effect, P = 0.35). Altogether, these results indicate that the 894G>T polymorphism reduced exercise-mediated increase in vascular reactivity, particularly when it occurred concomitantly with the -786T>C polymorphism.