Angiotensinogen gene polymorphism as a risk factor for ischemic stroke

Exploring the Mechanism of Edaravone for Oxidative Stress in Rats with Cerebral Infarction Based on Quantitative Proteomics Technology

Objective

To explore the mechanism of edaravone in the treatment of oxidative stress in rats with cerebral infarction based on quantitative proteomics technology.

Method

The modified Zea Longa intracavitary suture blocking method was utilized to make rat CI model. After modeling, the rat was intragastrically given edaravone for 7 days, once a day. After the 7-day intervention, the total proteins of serum were extracted. After proteomics analysis, the differentially expressed proteins are analyzed by bioinformatics. Then chemoinformatics methods were used to explore the biomolecular network of edaravone intervention in CI.

Result

The neurological scores and pathological changes of rats were improved after the intervention of edaravone. Proteomics analysis showed that in the model/sham operation group, 90 proteins in comparison group were upregulated, and 26 proteins were downregulated. In the edaravone/model group, 21 proteins were upregulated, and 41 proteins were downregulated. Bioinformatics analysis and chemoinformatics analysis also show that edaravone is related to platelet activation and aggregation, oxidative stress, intercellular adhesion, glycolysis and gluconeogenesis, iron metabolism, hypoxia, inflammatory chemokines, their mediated signal transduction, and so on.

Conclusion

The therapeutic mechanism of edaravone in the treatment of CI may involve platelet activation and aggregation, oxidative stress, intercellular adhesion, glycolysis and gluconeogenesis, iron metabolism, hypoxia, and so on. This study revealed the serum protein profile of edaravone in the treatment of cerebral infarction rats through serum TMT proteomics and discovered the relevant mechanism of edaravone regulating iron metabolism in cerebral infarction, which provides new ideas for the study of edaravone intervention in cerebral infarction and also provides reference information for future research on the mechanism of edaravone intervention in iron metabolism-related diseases.

Gene polymorphisms of angiotensin-converting enzyme and angiotensinogen and risk of idiopathic ischemic stroke

OBJECTIVE

The renin-angiotensin system (RAS) is a hormonal signaling mechanism implicated in the atherosclerosis and regulation of blood pressure. Angiotensin-converting enzyme (ACE) a key enzyme in the RAS, plays important roles in vascular remodeling atherosclerosis, and ischemic stroke. The aim of this study was to examine the possible contribution of the I/D in the ACE gene, M235T and T174M in the angiotensinogen (AGT) gene polymorphisms with ischemic stroke in young Mexican population.

MATERIALS AND METHODS

A total of 224 patients with diagnosis of idiopathic ischemic stroke ≤45 years of age, and 224 controls matched by age and gender, were recruited from 2006 and 2016. The I/D, M235T and T174M polymorphisms were determined in all participants by PCR-RFLP.

RESULTS

There was a significant difference in the M235T genotype distribution (p = 0.01) and allele frequency between two groups (p = 0.01). Also, we found a significant difference in the T174M genotype distribution (p = 0.01) and the allele frequency between groups; (p = 0.02). In contrast, in I/D polymorphism, there was a similar genotype distribution; (p = 0.20) and allele distribution (p = 0.20). There were independent factors for ischemic stroke: M235T and T174M polymorphisms, smoking, hypertension, and familial history of atherothrombotic disease. The AGT levels were increased in the group of patients with stroke compared with the control group, but the AGT levels were not influenced by the allele or genotype in each polymorphism.

CONCLUSIONS

The M235T and T174M polymorphisms represented an increased risk for stroke in young Mexican individuals. In contrast, the I/D was not associated with in the same group of patients. The AGT levels were higher in the acute phase of stroke, but it was not determined by the polymorphisms.

Angiotensinogen gene polymorphism and ischemic stroke in East Asians: A meta-analysis

Objective:

To investigate the association between angiotensinogen gene M235T polymorphism and ischemic stroke in East Asians.

Data Retrieval:

A computer-based online search was conducted in PubMed, Google scholar, China National Knowledge lnfrastructure database between January 1990 and April 2012 for relevant studies. The key words were angiotensinogen or AGT, polymorphism or genetic and ischemic stroke or cerebral infarction.

Selection Criteria:

Case-controlled studies addressing the correlation between angiotensinogen gene M235T polymorphism and ischemic stroke in East Asians were included. The distribution of genotypes in the included studies was tested for Hardy-Weinberg equilibrium. Quality evaluation of the included studies was conducted by two physicians. Statistical analyses were carried out using Stata 12.0 software for meta-analysis. Heterogeneity tests, sensitivity analysis and publication bias were also conducted.

Main Outcome Measures:

The association between angiotensinogen gene M235T polymorphism and ischemic stroke risk in East Asians was assessed.

Results:

Six relevant studies involving 891 patients with ischemic stroke and 727 controls were included in this meta-analysis. Results showed that there was a significant association between angiotensinogen gene M235T polymorphism and the risk of ischemic stroke in East Asians (T vs. M: odds ratio (OR) = 1.54, 95% confidence interval (CI) = 1.10–2.16; TT vs. MM: OR = 2.24, 95%CI = 1.37–3.66; TT vs. MT: OR = 1.76, 95%CI = 1.41–2.20; MM + MT vs. TT: OR = 0.57, 95%CI = 0.46–0.70). Sensitivity analysis confirmed that the study results were stable and reliable, with no publication bias.

Conclusion:

The angiotensinogen gene M235T polymorphism is associated with ischemic stroke in East Asians, and the TT genotype and T allele are risk factors for ischemic stroke.

Revising the M235T polymorphism position for the AGT gene and reporting a modifying variant in the Brazilian population with potential cardiac and neural impact

There is a growing need to curate the overwhelming amount of sequencing data which is available in many public databases. For instance, new information shows that the M235T polymorphism at the angiotensinogen gene (AGT) is actually positioned at the position corresponding to the amino acid 268 and not 235. This polymorphism is filled as rs699 in the NCBI SNP database and results in the synthesis of a threonine (T) instead of a methionine (M). It has been widely studied and associated as an important risk factor for several vascular and neuropsychiatric conditions. We faced this new situation during the targeted sequencing of 360 chromosomes from Brazilian subjects studied for the M235T polymorphism, leading to the identification of a novel variation (rs141900991). This report explores the potential impact of such a dinucleotide variation, which promotes the change of alanine (A) to serine (S) at the AGT protein structure (A237S). Considering the previous M268T variation at the four possible haplotypes combined (MA, MS, TA and TS), we performed a comparative hydrophobicity simulation, using the Kyte-Doolittle algorithm, available at the CLB Bio workbench, in the four possible haplotypes. Additional simulations were performed using the programs PolyPhen, I-Mutant and SIFT, in order to evaluate the pathogenicity of both mutations. The predicted hydrophobicity decreases of a similar magnitude, with both MS and TA haplotypes, but the presence of both variations induces a major decrease in hydrophobicity, suggesting a cumulative effect, with possible modifying effect since that this variation per se would limit the hydrophobicity range and the latter chances in finding significant phenotype differences. A better characterization of this kind of variant is particularly important because the current genome wide scan analyses in complex disorders with cardiac or neural etiology are not generating reliable findings, especially if we consider the huge investment with such approach. Additional and unknown variations like this one, with potential modifying effect, might be more common than previously expected.

Aldosterone synthase gene (CYP11B2) promoter polymorphism as a risk factor for ischaemic stroke in Tunisian Arabs

INTRODUCTION

We investigated the contribution of aldosterone synthase CYP11B2 polymorphism (C-344T) to the age-related changes in blood pressure in stroke patients.

SUBJECTS AND METHODS

Study subjects comprised 329 stroke patients (121 normotensive, 208 hypertensive) and 444 healthy controls. Genotyping was done by PCR-RFLP, and the contribution of CYP11B2 polymorphism to the risk of stroke was analysed by regression analysis.

RESULTS

The T allele, and CT, TT, and CT + TT genotypes, independently of sex and age, were significantly associated with increased stroke risk. Varied distributions of CYP11B2 genotypes were noted among patients with respect to gender, age and hypertension status, being pronounced in hypertensive patients. Both systolic and diastolic blood pressure were positively correlated with the presence of T allele. Mean systolic and diastolic blood pressure were significantly higher among young (< 60 years) CT and TT genotype carriers. Regression analysis confirmed the positive association of CT and TT genotypes and systolic blood pressure, and the negative association of diastolic blood pressure with odds of stroke development. Taking normotensive patients as reference, regression analysis identified TT genotype, age and female gender to be independently associated with increased odds of stroke.

CONCLUSION

Compared to CC genotype, CT and TT CYP11B2 genotypes are independently associated with increased stroke index.

Hypertension is a major risk factor for future atherosclerotic changes in the Japanese population

Background

Great differences in age-standardized mortality rates by cardiovascular disease exist among countries. We prospectively assessed determinants of future cardiovascular changes in a Japanese cohort.

Methods

In 1996, 1011 men and 1153 women from a Japanese community participated in a study on cardiovascular risk factors at a local health centre. Of these, the 896 subjects who visited the centre both in 1996 and 2001 were selected for the analysis. The presence of cardiovascular changes was defined as the appearance of one or more of the following in five years: positive electrocardiographic findings, intima–media thickness of the carotid artery ≥0.8 mm and retinal vascular changes ≥Keith–Wegener–Barker classification stage I.

Results

Of the 607 subjects who had no history of cardiovascular disease in 1996, 421 showed changes in 2001. Both the age-adjusted and multivariate models showed that the risk of the cardiovascular changes increased as systolic blood pressure (SBP) increased to ≥135 mmHg (multivariate odds ratio = 1.739, 95% confidence interval = 1.076–2.810, P < 0.05) compared with those with an SBP of 110–134 mmHg. When we made the analyses only for laboratory test results by excluding SBP, body mass index, alcohol intake and current smoking from the regression model, high-density lipoprotein cholesterol and fasting plasma glucose were significant variables.

Conclusion

The risk of future cardiovascular changes is significantly greater with higher SBP in the Japanese population.

Association between renin-angiotensin-aldosterone system genotypes and haplotypes and risk of ischemic stroke of atherosclerotic etiology

OBJECTIVE

The association of renin C-4063T and angiotensinogen (AGT) T174M, AGT M235T and AGT A-6G polymorphisms with ischemic stroke of atherosclerotic etiology was investigated in 329 Tunisian patients with stroke and 444 controls.

MATERIALS AND METHODS

Genotyping was performed using PCR-RFLP and the contributions of polymorphisms to the risk of stroke were analyzed using haplotype and multivariate regression analysis.

RESULTS

AGT 235T and AGT-6G allele and AGT 235T/T, AGT-6A/G and AGT-6G/G genotype frequencies were higher in patients. Linkage disequilibrium (LD) was noted for AGT174T with AGT235M and AGT(-6)A in patients, while AGT235M was in LD with AGT(-6)A in controls and AGT235T was in LD with AGT(-6)G in both groups. The AGT 174T/235T/-6A and AGT 174T/235M/-6G haplotypes were positively and negatively associated with stroke respectively. Multivariate regression analysis identified AGT 174T/235M/-6A, AGT 174T/235T/-6G, AGT 174T/235T/-6A and AGT 174M/235T/-6A haplotypes to be significantly associated with an increased risk of stroke.

CONCLUSIONS

Renin-angiotensin-aldosterone system polymorphisms influence the risk of atherosclerotic stroke in Tunisians.

Angiotensin-converting enzyme (ACE), angiotensinogen (AGT), and angiotensin II type 1 receptor (AT1R) gene polymorphisms in generalized aggressive periodontitis

AIM

Host response to periodontopathic microorganisms can be modulated by genetic factors. Accumulated evidence highlighted the role of renin-angiotensin system (RAS) in inflammatory response thus potential implication of this molecular system in the pathogenesis of periodontitis can be suggested. The present study investigated common genetic variants of molecules within the RAS family namely angiotensin-converting enzyme (ACE), angiotensinogen (AGT) and angiotensin II type 1 receptor (AT1R) in relation to generalized aggressive periodontitis (G-AgP).

METHODS

DNA was obtained from peripheral blood of 103 G-AgP patients and 100 periodontally healthy subjects. ACE I/D, AGT M235T and AT1R A1166C polymorphisms were genotyped by polymerase chain reaction and restriction fragment length polymorphism method. Chi-square, ANOVA and logistic regression were used in statistical analyses.

RESULTS

Both ACE I/D and AT1R polymorphisms were similar in G-AgP and healthy groups (p>0.05). G-AgP subjects exhibited decreased AGT TT genotype and T allele frequency as compared to healthy subjects (p<0.05). The same trend was also observed in the nonsmoker subgroup regarding investigated RAS polymorphisms.

CONCLUSIONS

Present findings suggest that AGT M235T TT genotype and T allele might be associated with decreased risk for G-AgP in Turkish population.