Relationship between endothelial nitric oxide synthase gene polymorphisms and ischemic stroke: a meta-analysis

Endothelial Nitric Oxide Synthase (Glu298Asp) Polymorphism is Associated Significantly with Ischemic Stroke Presenting with Seizures and Altered Sensorium

Background

Endothelial nitric oxide synthase (eNOS) is an enzymatic marker whose genetic polymorphism might predispose to acute ischemic stroke (AIS) via vascular endothelial dysfunction. It has a potential role in atherosclerosis, making it a plausible risk factor for stroke. Prior studies have failed to prove a conclusive relationship between eNOS polymorphism and AIS.

Objective

The aim of this study is to find an association between the presence of eNOS polymorphism (Glu298Asp) and the risk of developing AIS.

Materials and Methods

We recruited 307 subjects including 153 AIS cases and 154 healthy controls. The eNOS (Glu298Asp) polymorphism was identified in EDTA blood by PCR amplification of the target region followed by restriction enzyme digestion, and genotyping on Agarose gel. GG, GT and TT genotypes were obtained. Statistical analysis was done using SPSS software version 20.

Results

A significant association was found between the presence of TT genotype and the risk of AIS (Odd's ratio (OR): 2.43, P-value = 0.038). There was no significant association between the TT genotype and the traditional stroke risk factors. However, the TT genotype was significantly associated with the presence of altered consciousness (OR: 5.27, 95% CI: 1.59-17.04, P-value = 0.003) and with the occurrence of seizures at presentation (OR: 7.98, 95% CI: 1.99-32.09, P-value = 0.007).

Conclusions

There is a significant association between the presence of eNOSpolymorphism (Glu298Asp) and the risk of AIS, and the TT genotype may predispose to a more severe initial presentation of ischemic stroke.

Ischemic stroke in Morocco: a systematic review

Background

The aim of this systematic review is to determine the epidemiological and etiological profiles, the influential factors of the prehospital delay, thrombolysis management, the acute and 3-month mortality rate and the genetic aspect of ischemic stroke in Morocco.

Methods

The present work is a systematic review that was conducted according to the recommendations of the “Preferred reporting items for systematic reviews and meta-analysis”. We used Pubmed, Sciencedirect, Scopus, Clinicalkey, and Google scholar databases for the raking of the gray literature during the time frame 2009 and 2018. The protocol of the review was registered in the PROSPERO register (CRD42018115206).

These studies were analyzed based on: Age, sex ratio, risk factors, etiological profile according to Trial of ORG classification 10,172 in Acute Stroke Treatment, prehospital delay average and its influential factors, thrombolyzed patients’ proportion, acute and 3-month mortality and the genetic factors of ischemic stroke in Morocco.

Results

Twenty-nine (n = 29) studies were selected. The average age ranged from 49 ± 15.2 to 67.3 ± 9.9 years old. Moreover, we reported male predominance within all ages in 13 studies. High blood pressure, diabetes, smoking and heart disease were the four identified main risk factors by the prementioned studies. Atherosclerosis and cardioembolic were the main described etiologies of cerebral ischemia, and the average prehospital time ranged from 26 to 61.9 h. The proportion of thrombolysed patients ranged from 1.8% to 2.9%, the mortality rate varied in the acute phase from 3 to 13%, and the 3-month mortality ranged from 4.3 to 32.5%. It is also important to highlight that most of these studies, which were conducted in hospital environment, have a reduced sample size and no confidence interval.

Conclusions

Ischemic stroke is affecting more likely the young population with male predominance. Moreover, the long prehospital delay and the low proportion of thrombolysed patients are alarming. This indicates the need to investigate in depth the key factors influencing the access to care for Moroccan patients in order to improve the management of this neurologic deficit in Morocco.

Polymorphisms of MTHFR, eNOS, ACE, AGT, ApoE, PON1, PDE4D, and Ischemic Stroke: Meta-Analysis

INTRODUCTION

The association between ischemic stroke and genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR; 677C>T and 1298A>C), endothelial nitric oxide synthase (eNOS; -786T>C, +894G>T, and variable number tandem repeat [VNTR]), phosphodiesterase 4D (PDE4D; SNPs 83 and 87), angiotensin-converting enzyme (ACE) I/D, angiotensinogen (AGT) 235M>T, paraoxonase 1 (PON1) 192Q>R, and apolipoprotein E (ApoE) ε2ε3ε4 remains inconclusive. Therefore, this updated meta-analysis aimed to clarify the presumed influence of genetic polymorphisms on ischemic stroke by meta-analyzing the comprehensive coverage of all individual association studies.

METHODS

All case-control studies published in different languages such as English, Japanese, Korean, Spanish, Chinese, Hungarian, Ukrainian, or Russian were identified from databases. The pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated via fixed- and random-effect models. Sensitivity analysis, heterogeneity test, Hardy Weinberg Equilibrium, and Egger's regression analyses were performed in this study.

RESULTS

A total of 490 case-control studies with 138,592 cases and 159,314 controls were included in this meta-analysis. Pooled ORs from all the genetic models indicated that MTHFR 677TT and 1298CC, eNOS +894TT and VNTR, PDE4D SNP 83, ACE DD, AGT 235TT, PON1 192RR, and ApoE ε4 polymorphisms were increasing the risks of ischemic stroke. Nevertheless, PDE4D SNP 87 and eNOS -786T>C polymorphisms are not associated with ischemic stroke risks.

CONCLUSIONS

Hence, the evidence from this meta-analysis concluded that MTHFR (677C>T and 1298A>C), eNOS (+894G>T and VNTR), PDE4D SNP 83, ACE I/D, AGT 235M>T, PON1 192Q>R, and ApoE ε2ε3ε4 polymorphisms predispose individuals to ischemic stroke.

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.

Interplay between polymorphisms in the endothelial nitric oxide synthase (eNOS) gene and metabolic syndrome in determining the risk of ischemic stroke in Koreans

BACKGROUND

Endothelial nitric oxide synthase (eNOS) gene variants are known to play a role in atherosclerotic development. However, whether interplay between eNOS polymorphisms and metabolic syndrome (MetS) affects ischemic stroke (IS) risk has yet to be discovered. We investigated whether the combined effects of eNOS polymorphisms and MetS influence ischemic stroke risk in Koreans.

METHODS

We genotyped the eNOS -922A>G, -786T>C, 4a4b, and 894G>T polymorphisms in 531 IS cases and 502 controls using polymerase chain reaction-amplified DNA. We then investigated whether the presence of MetS and the number of MetS risk factors worked with eNOS polymorphisms to influence IS risk.

RESULTS

IS patients had a significantly higher prevalence of MetS than controls [adjusted odds ratio (AOR)=2.943, 95% confidence interval (CI), 2.256-3.840, P<0.0001], and MetS prevalence did not differ between stroke subtypes. The 894GT+TT genotypes were positively associated with IS (AOR=1.670, 95% CI, 1.208-2.308, P=0.002), and the -786TC+CC genotypes showed co-morbidity with MetS (AOR=1.448, 95% CI, 1.401-2.015, P=0.028). Among subjects with three or more MetS risk factors, the highest AOR value (28.490, 95% CI, 3.162-256.688) was observed for the eNOS -786TC+CC genotypes.

CONCLUSIONS

The eNOS 894T allele and interplay between the eNOS -786C allele and MetS may predispose Koreans to IS.

Association between a 27-bp variable number of tandem repeat polymorphism in intron 4 of the eNOS gene and risk for diabetic retinopathy Type 2 diabetes mellitus: a meta-analysis

PURPOSE

Imbalance in the production of endothelial nitric oxide synthase (eNOS), which plays an essential role in retinal vascular function, can lead to the development of diabetic retinopathy (DR). To thoroughly address this issue, we performed an updated meta-analysis to evaluate the association between the eNOS 27VNTR (4b/4a) polymorphism and DR in type 2 diabetes mellitus (T2DM).

METHODS

A search was conducted of PubMed and Chinese language (WanFang) databases through 3 March 2013. Data were retrieved in a systematic manner and analyzed using Stata Statistical Software. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

RESULTS

Based on the search criteria for DR susceptibility related to the 27VNTR (4b/4a) polymorphism of the eNOS gene, 16 case-control studies (15 articles), comprising 3227 T2DM patients with DR and 3437 T2DM patients without DR, were retrieved. Although no significant associations were uncovered in either the overall analysis or DR subtype groups, a decreased association was detected between the African- (allelic contrast: OR = 0.75, 95% CI = 0.65-0.88) or population-based (PB) studies (dominant genetic model: OR = 0.91, 95% CI = 0.83-0.98) and the eNOS 27VNTR (4b/4a) polymorphism. Stratification according to average duration of DM revealed that T2DM patients with histories of >10 years had an elevated susceptibility to DR compared with those with histories of shorter durations (homozygote comparison: OR = 1.67, 95% CI = 1.09-2.58).

CONCLUSIONS

The present meta-analysis suggests that the eNOS 27VNTR (4b/4a) polymorphism potentially decreases the risk of developing DR in T2DM African individuals. The higher degree of susceptibility in patients with longer (>10 years) durations of DM is indicative of the involvement of a gene-environment interaction in determining the risk for DR. Further studies, based on larger sample sizes and additional gene-environment interactions, should be conducted to elucidate the role of eNOS gene polymorphisms, especially 27VNTR (4b/4a), in the risk for DR.

NOS3 894G>T polymorphism is associated with progression of kidney disease and cardiovascular morbidity in type 2 diabetic patients: NOS3 as a modifier gene for diabetic nephropathy?

BACKGROUND/AIMS

We have previously associated SNP 894G>T in the NOS3 gene with diabetic nephropathy (DN) using multi-locus analysis. Variant 894G>T has been widely studied as a DN susceptibility factor with contradictory results. In the present study we genotyped 894G>T in the cohort of prospectively followed type 2 diabetics with the aim to investigate its possible role in the progression of DN and development of morbidity and mortality associated with diabetes.

METHODS

311 subjects with defined stage of DN were enrolled in the study and followed up for a median of 38 months. We considered three end-points: progression of DN, major cardiovascular event and all-cause mortality.

RESULTS

Considering baseline GFR, age at enrolment and diabetes duration as confounders, Cox regression analysis identified 894GT genotype as a risk factor for DN progression (HR = 1.843 [95% CI 1.088 - 3.119], P = 0.023) and 894TT genotype as a risk factor for major cardiovascular event (HR = 2.515 [95% CI 1.060 - 5.965], P = 0.036).

CONCLUSION

We ascertained the significant effect of the NOS3 894G>T variant on DN progression and occurrence of major cardiovascular event in T2DM subjects. Based on these results NOS3 can be considered a modifier gene for DN.

Neurological disorders in a murine model of chronic renal failure

Cardiovascular disease is highly prevalent in patients with chronic renal failure (CRF). However, data on the impact of CRF on the cerebral circulatory system are scarce—despite the fact that stroke is the third most common cause of cardiovascular death in people with CRF. In the present study, we examined the impact of CRF on behavior (anxiety), recognition and ischemic stroke severity in a well-defined murine model of CRF. We did not observe any significant increases between CRF mice and non-CRF mice in terms of anxiety. In contrast, CRF mice showed lower levels of anxiety in some tests. Recognition was not impaired (vs. controls) after 6 weeks of CRF but was impaired after 10 weeks of CRF. Chronic renal failure enhances the severity of ischemic stroke, as evaluated by the infarct volume size in CRF mice after 34 weeks of CRF. Furthermore, neurological test results in non-CRF mice tended to improve in the days following ischemic stroke, whereas the results in CRF mice tended to worsen. In conclusion, we showed that a murine model of CRF is suitable for evaluating uremic toxicity and the associated neurological disorders. Our data confirm the role of uremic toxicity in the genesis of neurological abnormalities (other than anxiety).

The neuroprotective effects of Coccomyxa gloeobotrydiformis on the ischemic stroke in a rat model

Stroke is a major cause of mortality and the leading cause of permanent disability. In this study, we adopted the classic middle cerebral artery occlusion(MCAO) stroke model to observe the therapeutic effects of coccomyxa gloeobotrydiformis(CGD) on ischemic stroke, and discuss the underlying mechanisms. Low dose (50 mg/kg.day) and high dose (100 mg/kg.day) concentrations of the drug CGD were intragastrically administrated separately for 8 weeks. Infarct volumes, neurologic deficits and degree of stroke-induced brain edema were measured 24 hours after reperfusion. Furthermore, oxidative stress related factors (SOD and MDA), mitochondrial membrane potential, and apoptosis regulatory factors (mitochondrial Cyt-C, Bcl-2, Bax, and caspase-3) were all investigated in this research. We found that CGD attenuated cerebral infarction, brain edema and neurologic deficits; CGD maintained the mitochondrial membrane potential and decreased mitochondrial swelling. It also prevented oxidative damage by reducing MDA and increasing SOD. In addition, CGD could effectively attenuate apoptosis by restoring the level of mitochondrial Cyt C and regulating the expression of Bcl-2, Bax and caspase 3. These results revealed that CGD has a therapeutic effect on ischemic stroke, possibly by inducing mitochondrial protection and anti-apoptotic mechanisms.