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

Association studies of vasoactive genes and preeclampsia in taiwan

BACKGROUND

Preeclampsia (PE) is a serious condition characterized by hypertension and proteinuria after 20 weeks of gestation. The exact cause of PE is unknown but may involve abnormalities in the renin-angiotensin-aldosterone system (RAAS) and endothelial nitric oxide synthase (eNOS). Genetic variations in angiotensinogen (AGT), angiotensin-converting enzyme (ACE), and eNOS genes have been associated with PE. This study aimed to investigate the potential of vasoactive-related gene polymorphisms as indicators of susceptibility to preeclampsia in Taiwanese women.

METHODS

A total of 109 women with severe PE and 150 controls from the Taiwanese population were genotyped for specific vasoactive gene polymorphisms, including M235T and T174M polymorphisms of AGT gene, insertion/deletion (I/D) polymorphism in ACE gene, and G894T (Glu298Asp) polymorphism and 27bp variable number of tandem repeats (VNTR 3/4/5) polymorphism of the eNOS gene. The association between genotype and disease was assessed using Chi-square tests.

RESULTS

The study found no significant differences in the M235T and T174M polymorphisms of AGT gene between the PE and control groups. However, haplotype frequencies for the M235T and T174M polymorphisms exhibited a significant association with PE. The genotype distributions of the I/D polymorphism of ACE gene showed a significant difference between PE and control groups. Additionally, no significant differences were detected in the polymorphisms of the eNOS gene between PE and control groups.

CONCLUSION

The findings of this study suggest that the AGT M235T-T174M haplotype and ACE insertion/deletion polymorphism may contribute to the development of preeclampsia and could serve as susceptibility markers for preeclampsia in Taiwanese women.

Genetic Polymorphisms of Endothelial Nitric Oxide Synthase Associated with Hypertension and Blood Homocysteine Levels

Purpose

Endothelial dysfunction is a key mechanism in the development of hypertension and is closely linked to impairment of endothelial nitric oxide synthase (eNOS) and hyperhomocysteinemia. Genetic polymorphisms of eNOS (rs1799983 and rs2070744) are strongly associated with the risk of hypertension in individuals of Asian ethnicities. This study aimed to investigate the relationship between these polymorphisms and the risk of hypertension associated with homocysteine levels.

Participants and Methods

For this cross-sectional study, we enrolled 370 Thai men aged 40-60 years from the Electricity Generating Authority of Thailand cohort study for both variants genotyping by TaqMan allelic discrimination analysis. Clinical, anthropometric, and biochemical parameters were also analyzed.

Results

In the high blood pressure group (n = 267), systolic and diastolic blood pressure and triglyceride levels were higher in those with homocysteine levels ≥ 15 µmol/L than in those with homocysteine levels < 15 µmol/L (p < 0.05). Significant risk of hypertension was found in GG and GT of rs1799983 (G894T), and in TT and TC of rs2070744 (T-786C), with higher ORs in heterozygous genotypes (all p values < 0.05). Further evaluation of the interactions between SNPs and HCY revealed that individuals with the GT or TC genotype, together with hyperhomocysteinemia, had an increased risk of hypertension (all p<0.05).

Conclusion

eNOS variants rs1799983 and rs2070744 may be risk factors for hypertension linked to hyperhomocysteinemia. These findings provide potentially useful healthcare strategies for the management of hypertension.

Association of Endothelial Nitric Oxide Synthase 894G > T Polymorphism with Preeclampsia Risk: A Systematic Review and Meta-Analysis based on 35 Studies

Several case-control studies have been performed to investigate the association between 894 G > T polymorphism in endothelial nitric oxide synthase (eNOS) gene and susceptibility to preeclampsia. However, the results were inconsistent and inconclusive. Therefore, we conducted this meta-analysis to investigate the association. Methods: All studies published up to September 30, 2019 were identified by searching electronic databases such as PubMed, EMBASE, CNKI, and WANFANG. Results: A total of 35 case- control studies with 4,254 cases and 5,801 controls were selected. There was a significant association between the eNOS 894 G > T and preeclampsia risk. When stratified by ethnicity, an increased risk of preeclampsia was found in Caucasian and Mixed populations, but not in Asians or Africans. Conclusion: Based on our meta-analysis, the eNOS 894 G > T polymorphism was associated with an increased risk of preeclampsia, especially among Caucasian and Mixed populations.

The Role of Single Nucleotide Variants of NOS1, NOS2, and NOS3 Genes in the Development of the Phenotype of Migraine and Arterial Hypertension

Migraine (M) and arterial hypertension (AH) are very common diseases. Today, there are a number of studies confirming and explaining their comorbidity. We searched PubMed, Springer, Scopus, Web of Science, Clinicalkeys, and Google Scholar databases for full-text English publications over the past 15 years using keywords and their combinations. The present review provides a synthesis of information about single nucleotide variants (SNVs) of NOS1, NOS2, and NOS3 genes involved in the development of M and essential AH. The results of studies we have discussed in this review are contradictory, which might be due to different designs of the studies, small sample sizes in some of them, as well as different social and geographical environments. Despite a high prevalence of the M and AH phenotype, its genetic markers have not yet been sufficiently studied. Specifically, there are separate molecular genetic studies aimed to identify SNVs of NOS1, NOS2, and NOS3 genes responsible for the development of M and those responsible for the development of AH. However, these SNVs have not been studied in patients with the phenotype of M and AH. In this review, we identify the SNVs that would be the most interesting to study in this aspect. Understanding the role of environmental factors and genetic predictors will contribute to a better diagnostics and exploration of new approaches to pathogenetic and disease-modifying treatment of the M and AH phenotype.

The effect of consuming Pokea clam meat on nitric oxide plasma levels in hypertensive patients in Sampara District, Konawe District

The high number of vitamins and minerals in Pokea meat encouraged us to determine the effect of consuming Pokea meat on Nitric Oxide Plasma levels in patients with hypertension and normotension. This study aimed to analyze Pokea meat consumption (Batissa violacea var. celebensis von Martens) on plasma oxide (NO) levels in hypertensive patients in Sampara, Konawe District. This research uses an observational analytic method with a case-control study design through molecular biology approach. The sample comprises 60 people consisting of 30 case samples and 30 control samples using the purposive sampling technique. Laboratory examination data is on NO plasma levels. Statistical analysis used data analysis use-dependent t-test. The distribution of Pokea meat consumption variables in the Hypertension group respondents had a mean value of 35.14 ± 17.66, while in the Non-Hypertension group of respondents was 41.10 ± 19.82. In the variable nitric oxide, the Hypertension group had a mean and standard deviation of 69.48 ± 42.78 µmol / L while the Non-Hypertension group had a mean and standard deviation of 262.8 ± 39.90 µmol / L. The statistical test analysis results showed an effect of Pokea consumption on plasma NO levels (p = 0,000). Pokea Consumption Influences NO Plasma Levels in Hypertension Patients, and there are also differences in NO Plasma Levels in Patients with Hypertension and non-hypertension in Sampara District, Konawe District, Southeast Sulawesi.

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.

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.

Diabetic Kidney Disease and Hypertension: A True Love Story

INTRODUCTION

Diabetes Mellitus (DM) remains one of the commonest causes of structural and functional kidney abnormalities leading to End Stage Renal Disease (ESRD). The next most common cause is hypertension. It is utmost important to investigate the association between diabetic nephropathy and hypertension because it is a major causal factor of end-stage kidney failure in Type 2 Diabetes Mellitus (T2DM).

AIM

The aim of the present study was to investigate the association between albuminuria, hypertension and estimated glomerular filtration rate (eGFR) in a prospective cohort of T2DM patients in a developing country.

MATERIALS AND METHODS

A total of 824 patients were enrolled from a tertiary healthcare center in central India. This study was performed in three groups: normal controls (232), type 2 diabetics without nephropathy (185) and type 2 diabetics with nephropathy (407). Diabetic nephropathy was clinically defined by the presence of persistent proteinuria of > 500mg/day in a diabetic patient in the absence of clinical or laboratory evidence of other kidney or urinary tract disease. Hypertension was categorized based on JNC 7 classification. Detailed clinical history was obtained from all subjects. Student's t-test was applied to see the difference in mean values of quantitative data in two groups. Chi-Square test was applied to see the difference in frequency of discrete variables in two groups.

RESULTS

A 66.3% diabetic nephropathy patients and 51.9% type 2 diabetics without nephropathy were found hypertensive in present study; In contrast only 14.7% controls had hypertension. No association of hypertension was found with age and gender in either group. Serum creatinine and eGFR was found significantly different in hypertensive diabetic nephropathy patients than normotensive (p=0.002 and <0.0001 respectively).

CONCLUSION

Our study found that hypertension was an independent risk factor for the Diabetic Kidney Disease (DKD). Along with this, a proportional increase in the level of serum creatinine and eGFR was seen with an incidence of hypertension in diabetic nephropathy.

A multilevel prediction of physiological response to challenge: Interactions among child maltreatment, neighborhood crime, endothelial nitric oxide synthase gene (eNOS), and GABA(A) receptor subunit alpha-6 gene (GABRA6)

Physiological response to stress has been linked to a variety of healthy and pathological conditions. The current study conducted a multilevel examination of interactions among environmental toxins (i.e., neighborhood crime and child maltreatment) and specific genetic polymorphisms of the endothelial nitric oxide synthase gene (eNOS) and GABA(A) receptor subunit alpha-6 gene (GABRA6). One hundred eighty-six children were recruited at age 4. The presence or absence of child maltreatment as well as the amount of crime that occurred in their neighborhood during the previous year were determined at that time. At age 9, the children were brought to the lab, where their physiological response to a cognitive challenge (i.e., change in the amplitude of the respiratory sinus arrhythmia) was assessed and DNA samples were collected for subsequent genotyping. The results confirmed that complex Gene × Gene, Environment × Environment, and Gene × Environment interactions were associated with different patterns of respiratory sinus arrhythmia reactivity. The implications for future research and evidence-based intervention are discussed.

Correlation between polymorphism of endothelial nitric oxide synthase and avascular necrosis of femoral head

OBJECTIVE

We analyzed the correlation between mutation in intron 4 and exon 7 of endothelial nitric oxide synthase (eNOS) and avascular necrosis of femoral head (ANFH).

METHOD

A total of 260 ANFH cases without history of hip joint injuries were diagnosed and subject to staging according to Ficat standard, with 262 health subjects as control. Venous blood was collected to extract genome DNA, which was then amplified by PCR. The polymorphism of 27 bp repeat sequence in intron 4 and G894T polymorphism in exon 7 of eNOS gene was detected.

RESULTS

The b/b, b/a and a/a genotype frequency of intron 4 was 77.7%, 19.2% and 3.1% in ANFH group, respectively, and that in the control group was 58.0%, 32.8% and 9.2%, respectively. The b allele frequency in ANFH group was obviously higher than that in the control (P<0.0001). The frequency of 894 G/G wild type, G/T heterozygote and T/T homozygote in eNOS exon 7 was analyzed by PCR-RLFP: 65.4%, 26.5% and 8.1% in ANFH group, and 46.2%, 37.8% and 16% in normal control, respectively. The frequency of TT genotype in ANFH was obviously higher than that in the control group (P<0.001).

CONCLUSION

Polymorphism of eNOS was correlated with ANFH.