Gene-gene interaction in the RAS system in the predisposition to myocardial infarction in elder population of St. Petersburg (Russia)

M235T polymorphism in the angiotensinogen gene and cardiovascular disease: An updated meta-analysis of 39 case-control comparisons

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Angiotensinogen-M235T as a risk factor for myocardial infarction in Asian populations: a genetic association study and a bioinformatics approach

Aim

To investigate if there is an association between M235T polymorphism of angiotensinogen gene and myocardial infarction (MI) risk and perform a meta-analysis and an in silico approach.

Methods

This case-control study included 340 participants (155 MI patients and 185 controls) examined at Kashan University of Medical Sciences (Kashan, Iran) between 2013 and 2015. Meta-analysis included 25 studies with 6334 MI patients and 6711 controls. Bioinformatics tools were applied to evaluate the impact of M235T polymorphism on angiotensinogen function and structure.

Results

Genetic association study revealed a significant association between TT genotype (odds ratio [OR] 2.08, 95% confidence interval [CI] 1.08-4.00, P = 0.029) and T allele (OR 1.45, 95% CI 1.06-1.99, P = 0.021) and MI risk. Meta-analysis also revealed a significant association between M235T polymorphism and MI risk in allelic (OR 1.55, 95% CI 1.10-2.18, P = 0.012) and recessive (OR 1.69, 95% CI 1.13-2.53, P = 0.010) models within Asian population. In silico-analysis revealed that M235T fundamentally changed the function of angiotensinogen (score 32; expected accuracy 66%).

Conclusions

Our study suggests that M235T polymorphism might be a helpful biomarker for screening of susceptible individuals for MI in Asian population.

Angiotensin-converting enzyme insertion/deletion polymorphism and risk of myocardial infarction in an updated meta-analysis based on 34993 participants

The association between angiotensin-converting enzyme insertion/deletion (ACE I/D) polymorphism and risk of myocardial infarction (MI) has been extensively studied. However, the results were in controversy. This study aimed to explore the association between ACE I/D polymorphism and risk of MI by using a meta-analysis. We retrieved the following databases to indentify eligible studies: Medline, Embase, ISI, VIP, CBM and Wan Fang database. The latest update was 10th May, 2012. Odds ratio and 95% confidence interval (95% CI) were used to present the strength of the association. A total of 40 case-control studies with 34993 participants were included. Overall, D allele of ACE I/D polymorphism was significantly associated with an increased risk of MI in genetic comparison models (OR (95% CI): 1.41 (1.22-1.64) for DD vs. II; 1.11 (1.01-1.21) for ID vs. II; 1.23 (1.10-1.37) for D carriers vs. II; 1.28 (1.15-1.43) for DD vs. I carriers and 1.06 (1.02-1.10) for D carriers vs. I carriers). Subgroup analyses, according to ethnicities and countries of participants also indicated that D allele was significantly associated with an increased risk of MI in Asians (especially for Chinese) and Caucasians (especially for English, French, Germans and Italians) (OR (95% CI) of DD vs. ID+II: 2.11 (1.65-2.70) for Asians and 1.15 (1.05-1.27) for Caucasians). In conclusion, this meta-analysis indicated that D allele of ACE I/D polymorphism was a possible risk factor for MI incidence for both Asians and Caucasians.

The M235T polymorphism in the angiotensinogen gene and myocardial infarction risk: a meta-analysis

OBJECTIVE

The angiotensinogen (AGT) gene M235T polymorphism has been reported to be associated with myocardial infarction (MI), but previous studies have been inconsistent. The present study aimed at assessing the association of M235T polymorphism in the AGT gene with MI using a meta-analysis.

METHODS

We retrieved literature in Google Scholar, PubMed, Cochrane Library and the China National Knowledge Infrastructure database (January 1990-December 2011) for the relevant studies on the AGT polymorphism M235T and risk of MI. Statistical analyses were carried out using Stata 10.0 for combining all the relevant studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association. Begg's test was used to measure publication bias.

RESULTS

A total of 21 case-control studies containing 5887 patients and 6164 controls were enrolled into this meta-analysis. Overall, significant association was found between the AGT gene M235T polymorphism and risk of MI in the subgroup analysis for TT vs MT in Asians (OR 1.47, 95% CI: 1.01-2.12; p = 0.04). No associations were detected between AGT M235T and the risk of MI in total population and Caucasians.

CONCLUSIONS

This meta-analysis demonstrated that the AGT M235T polymorphism could be a prediction marker for risk of MI in Asians. Conclusive evidence on the effects of the variants in MI should be addressed in further studies.

Interaction of A-240T and A2350G related genotypes of angiotensin-converting enzyme (ACE) is associated with decreased serum ACE activity and blood pressure in a healthy Iranian population

Most of renin-angiotensin system (RAS) gene polymorphisms have not yet been studied in the Iranian population. In the present study, the frequencies of common polymorphisms in the RAS genes, including angiotensin-converting enzyme (ACE) insertion/deletion (I/D) and three single-nucleotide polymorphisms (SNPs), i.e., A-240T, T-93C and A2350G, angiotensinogen M235T, angiotensin II receptor type 1 A1166C and angiotensin II receptor type 2 C3123A variants were determined in DNAs extracted from venous blood of 104 healthy Iranian volunteers. Genotyping was performed by PCR-RFLP method. Serum ACE activity was also assayed using reverse phase HPLC. Combined polymorphisms of TT (A-240T) and GG (A2350G) was significantly associated with decreased serum ACE activity (P=0.042) and decreased diastolic blood pressure (P=0.040). The angiotensin II receptor type 1 A1166C polymorphism (CC genotype) showed a significant association with declined diastolic blood pressure (P=0.028). Serum ACE activity was significantly higher in men compared to women (P=0.033). ACE activity also showed a direct association with diastolic blood pressure (P<0.001). No association was obtained among each single polymorphism with body mass index (BMI), fasting blood sugar (FBS), lipid profile and ACE activity. In conclusion, combined polymorphisms of A-240T and A2350G seem to affect serum ACE level as well as diastolic blood pressure in our study population. However, it also might be hypothesized that they are in strong linkage disequilibrium with other functional mutations not studied yet. Our findings revealed that gene interactions can play an important role in various biological conditions.

Angiotensin-converting enzyme insertion/deletion gene polymorphism in a Tunisian healthy and acute myocardial infarction population

INTRODUCTION

The role of the insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme gene (ACE) on acute myocardial infarction (AMI) is controversial.

OBJECTIVES

To assess the effect of the ACE I/D polymorphism on AMI compared with the healthy controls and its relationship with serum ACE activity in a Tunisian population.

DESIGN AND METHODS

A total of 119 patients with AMI were compared with 238 healthy controls from the same geographical area. ACE genotyping was determined by polymerase chain reaction, and serum ACE activity was measured with N-[3-(2-furylacryloyl]-L-phenylalanyl-L-glycyl-L-glycine as substrate.

RESULTS

The ACE I/D polymorphism was significantly different between patients and controls (p < 0.0001). The frequencies of the DD genotype and the D allele were statistically higher in patients with AMI as compared with the controls and were associated with increased risk of AMI (DD vs. ID and II: odds ratio = 4.27, p < 0.0001, 95% confidence interval = 2.65-6.86; D vs. I: odds ratio = 3.15, p < 0.0001, 95% confidence interval = 2.26-4.40). This association was independent of other cardiovascular risk factors but dyslipidemia (p = 0.002) that was not represented in AMI patients with II genotype and in a lower extent with hypertension (p < 0.05). Serum ACE activity was significantly higher in AMI patients with ACE DD genotype compared with the subjects with ID or II genotype (p = 0.034) and was not correlated with other cardiovascular risk factors.

CONCLUSIONS

ACE DD genotype associated with higher serum ACE activity is increased in the studied population and might be clinically useful as markers to assess risk for AMI.

Prevalence of the angiotensin I converting enzyme gene insertion/deletion polymorphism in a healthy Turkish population

Angiotensin converting enzyme (ACE) plays an essential role in the renin-angiotensin system. It converts angiotensin I to angiotensin II and inactivates bradykinin and tachykinins. Numerous studies have been published investigating associations of the ACE gene I/D polymorphism with various pathophysiological conditions. We examined the prevalence of the ACE I/D polymorphism in a sample of healthy volunteers from western Turkey, including 1063 healthy Turkish controls. Analysis of the ACE I/D gene polymorphisms by polymerase chain reaction found frequencies of 16.1% for the II genotype, 47.7% for the ID genotype, and 36.2% for the DD genotype. The allele frequency was 39.9% for the I alleles and 60.1% for the D allele. This study demonstrates that the allele and genotype frequency values for the Turkish population are similar to previously published frequencies for Caucasian populations.

The M235T polymorphism in the AGT gene and CHD risk: evidence of a Hardy-Weinberg equilibrium violation and publication bias in a meta-analysis

Background

The M235T polymorphism in the AGT gene has been related to an increased risk of hypertension. This finding may also suggest an increased risk of coronary heart disease (CHD).

Methodology/Principal Findings

A case-cohort study was conducted in 1,732 unrelated middle-age women (210 CHD cases and 1,522 controls) from a prospective cohort of 15,236 initially healthy Dutch women. We applied a Cox proportional hazards model to study the association of the polymorphism with acute myocardial infarction (AMI) (n = 71) and CHD. In the case-cohort study, no increased risk for CHD was found under the additive genetic model (hazard ratio [HR] = 1.20; 95% confidence interval [CI], 0.86 to 1.68; P = 0.28). This result was not changed by adjustment (HR = 1.17; 95% CI, 0.83 to 1.64; P = 0.38) nor by using dominant, recessive and pairwise genetic models. Analyses for AMI risk under the additive genetic model also did not show any statistically significant association (crude HR = 1.14; 95% CI, 0.93 to 1.39; P = 0.20). To evaluate the association, a comprehensive systematic review and meta-analysis were undertaken of all studies published up to February 2007 (searched through PubMed/MEDLINE, Web of Science and EMBASE). The meta-analysis (38 studies with 13284 cases and 18722 controls) showed a per-allele odds ratio (OR) of 1.08 (95% CI, 1.01 to 1.15; P = 0.02). Moderate to large levels of heterogeneity were identified between studies. Hardy-Weinberg equilibrium (HWE) violation and the mean age of cases were statistically significant sources of the observed variation. In a stratum of non-HWE violation studies, there was no effect. An asymmetric funnel plot, the Egger's test (P = 0.066), and the Begg-Mazumdar test (P = 0.074) were all suggestive of the presence of publication bias.

Conclusions/Significance

The pooled OR of the present meta-analysis, including our own data, presented evidence that there is an increase in the risk of CHD conferred by the M235T variant of the AGT gene. However, the relevance of this weakly positive overall association remains uncertain because it may be due to various residual biases, including HWE-violation and publication biases.

Quantitative assessment of the effect of angiotensinogen gene polymorphisms on the risk of coronary heart disease

BACKGROUND

Angiotensinogen, a key protein in the renin-angiotensin system, plays an important role in cardiovascular hemostasis. Many studies have examined the association between polymorphisms in the angiotensinogen gene and risk of coronary heart disease (CHD), but the results have been inconsistent.

METHODS AND RESULTS

We performed a meta-analysis of 43 associations studies on 2 angiotensinogen polymorphisms (M235T and T174M) and risk of CHD published before March 2007, including a total of 13,478 CHD cases and 17,024 controls. We also explored potential sources of heterogeneity. In a combined analysis, the summary per-allele odds ratio for CHD of the M235T polymorphism was 1.11 (95% confidence interval, 1.03 to 1.19). However, when the analyses were restricted to 4 larger studies (n >500 cases), the summary per-allele odds ratio was 0.99 (95% confidence interval, 0.94 to 1.04). Our analyses detected a possibility of publication bias with an overestimate of the true association by smaller studies. A meta-analysis of studies on the 174M variant showed no significant overall association with CHD, yielding a per-allele odds ratio of 1.07 (95% confidence interval, 0.93 to 1.22).

CONCLUSIONS

This meta-analysis suggested an overall weak association between the M235T polymorphism and CHD risk. However, the association was not observed in several larger studies, suggesting a publication bias. Additional very large-scale studies are warranted to provide conclusive evidence on the effects of the angiotensinogen gene and other genes within the renin-angiotensin system on risk of CHD.

Renin-angiotensin polymorphisms and QTc interval prolongation in end-stage renal disease

BACKGROUND

Polymorphisms of renin-angiotensin system (RAS) genes in patients with end-stage renal disease (ESRD) on chronic hemodialysis may be associated with QTc interval prolongation, leading to fatal arrhythmias. The objective of this study was to determine (1) the prevalence of QTc prolongation in hemodialysis patients, and (2) the association of a prolonged QTc in these patients with RAS polymorphisms [angiotensin-converting enzyme-insertion/deletion (ACE-I/D), angiotensin type 1 receptor-A1166C (AT1R-A1166C), and angiotensinogen-M235T (AGT-M235T)].

METHODS

Twelve-lead electrocardiograms (ECGs), serum electrolytes (sodium, potassium, and calcium), and ACE and angiotensin II levels were obtained 10 to 12 hours after a hemodialysis session in 43 patients with ESRD on chronic hemodialysis [mean age (+/-SD), 55 +/- 14 years]. Using polymerase chain reaction (PCR), the presence of polymorphisms of the ACE-I/D, AT1R-A1166C, and AGT-M235T genes was determined from the buccal cells. A maximum QT interval in patients with sinus rhythm and normal QRS duration was corrected for heart rate using Hodges' formula.

RESULTS

Fifty-eight percent of the patients had QTc interval prolongation (>440 msec). The ACE-DD genotype (P = 0.002) and the C allele of the AT1R-A1166C gene (P = 0.004), but not the AGT-M235T gene, contributed to QTc prolongation.

CONCLUSION

Polymorphisms of ACE and AT1R genes additively contribute to QTc prolongation found in a great majority of ESRD patients. Therefore, ESRD patients with both or one of these polymorphisms may be at a higher risk for sudden cardiac death.

Genotypic interactions of renin-angiotensin system genes in myocardial infarction

BACKGROUND

Three-gene interactions among the genetic polymorphisms of the renin-angiotensin system (RAS) associated with acute myocardial infarction (AMI) have not been examined in a single population. We hypothesized that all types of gene-to-gene associations may occur in AMI, but that some will have a higher risk, depending on the gene frequencies.

METHODS

Polymorphisms of the AGT (M235T), ACE (I/D) and AGTR1 (A1166C) genes in AMI patients and controls were analyzed using the polymerase chain reaction. Classic coronary risk factors were analyzed in all individuals.

RESULTS

Logistic regression analysis of these factors and the genetic polymorphisms demonstrated that smoking, family history of CAD, arterial hypertension and total cholesterol were the most significant contributors to AMI. The genotypic frequencies for all three genes alone were similar between the infarction and control groups, with no increased risk of developing AMI. Double homozygous combinations for normal alleles (MM of AGT, II of ACE and AA of AGTR1) had a lower risk of AMI (odds ratio<0.38), indicating a protective effect in these individuals. In genotypic combinations that included at least one unfavorable allele, the risk (odds ratio) of developing AMI was 2.92, 2.63 and 2.68 for AGT vs. ACE, AGT vs. ATR1 and ACE vs. AGTR1, respectively. The positive interaction among the three genes and the risk of AMI had an odds ratio of 3.78 with a 95% CI of 0.88-12.85.

CONCLUSIONS

The risk of developing AMI is higher whenever there are unfavorable alleles in gene-to-gene associations in the RAS.

Gender and Ethnic Differences in a Case-Control Study of Dyslipidemia: Using the Apolipoprotein A-V Gene as an Exemplar in Cardiovascular Genetics

Common, complex genetic disorders such as coronary heart disease (CHD) frequently show large population differences, contributing to health disparities. It is also well known that CHD risk factor profiles and the frequency of coronary events differ by gender. Study of premature CHD has revealed that apolipoproteins are important discriminating factors for distinguishing individuals with CHD. Recent findings indicated that apolipoprotein A-V (APOA-V) gene promoter polymorphisms are an important determinant of plasma triglycerides (TG) and lipoprotein cholesterol, and a risk factor for CHD. Variations in APOA-V may have varying impacts in different ethnic groups. The purpose of this interdisciplinary genetic research project was to determine (1) the association of the APOA-V polymorphisms with lipoprotein profiles, and (2) the gender and ethnic differences in the T-1131C promoter polymorphism of the APOA-V gene in individuals with dyslipidemia versus controls. Results indicate that the minor -1131C allele (CC homozygotes + CT heterozygotes) was associated with elevated plasma TG (p= 0.007), very low density lipoprotein (VLDL)–TG (p= 0.019), LDL-TG (p= 0.004), high-density-lipoprotein (HDL)-TG (p< 0.001), and VLDL-cholesterol (p= 0.008). We found a striking elevation in the frequency of the minor C allele in Asians (p< 0.001) compared to Europeans. We also found a significant difference in genotype frequency between men and women in Asians (p= 0.031) and Europeans (p< 0.01). Remarkably, Asian women with the C allele have a 36% increase in TG compared to Asian women homozygous for the T allele. In summary, we found significant ethnic-specific and gender-based differences in the frequency of the minor allele of the -1131 APOA-V gene promoter polymorphism. Identification of genetic variations among ethnic groups and between genders may have significant potential for a better understanding of the development of cardiovascular disease.

Angiotensinogen gene polymorphism, plasma angiotensinogen, and risk of hypertension and ischemic heart disease: a meta-analysis

OBJECTIVE

The aim of this study was to investigate whether the M235T polymorphism in the angiotensinogen gene was associated with angiotensinogen levels, systolic and diastolic blood pressure, hypertension, and risk of ischemic cardiovascular disease in different ethnic populations.

METHODS AND RESULTS

One hundred twenty-seven studies published between January 1992 and March 2002 examining the association of angiotensinogen gene polymorphisms with the above-mentioned end points were selected. Pooled effect sizes and Mantel-Haenszel odds ratios were calculated using Review Manager. In white subjects, genotype was associated with a stepwise increase in plasma angiotensinogen levels of 5% (95% CI, 2% to 8%; P=0.0004) in MT heterozygotes and 11% (7% to 15%; P<0.00001) in TT homozygotes compared with MM individuals. Correspondingly, genotype was associated with a stepwise increase in aggregated odds ratio for hypertension of 1.08 (95% CI, 1.01 to 1.15) in MT individuals and 1.19 (1.10 to 1.30) in TT individuals in white subjects and of 1.29 (95% CI, 0.96 to 1.74) and 1.60 (1.19 to 2.15) in Asian subjects. M235T genotype did not predict systolic or diastolic blood pressure or risk of ischemic heart disease or myocardial infarction in either ethnic group.

CONCLUSIONS

Angiotensinogen M235T genotype was associated with a stepwise increase in angiotensinogen levels in white subjects and a corresponding increase in risk of hypertension in both white and Asian subjects.