ACE and AT1R gene polymorphisms and hypertension in Indian population

Analysis of the Pattern, Alliance and Risk of rs1799752 (ACE I/D Polymorphism) with Essential Hypertension

Studies in spontaneously hypertensive rat had revealed an elevated level of ACE gene expression in the tissues and is substantiated by experimental clinical studies for a positive correlation between ACE I/D polymorphism and hypertension. Aim: To determine whether the polymorphic variant of ACE gene in intron 16 confers susceptibility to essential hypertension. I/D polymorphism at the locus intron 16 of the ACE gene were amplified from the genomic DNA of the total 571 (hypertensive patients, n: 279; controls, n: 292) participants using polymerase chain reaction and gel electrophoresis methods and were examined in a case-control approach. Suitable descriptive statistics was used for different variables. Result revealed significant heterogeneity under the allele (p: 0.0002) and genotype (p: 0.0001) contrast in hypertensive patients than in normal controls, with an increased frequency of D allele (62.72%; p < 0.0001; OR: 1.8144; 95% CI: 1.4327-2.2979) and DD genotype (41.93%; p: < 0.0001). A significant association was found in the DD variant with disease phenotype (p: 0.0018, 95% CI: 1.3303-3.4907; OR: 2.1549; Table 31) and is substantiated by the data of multivariate analysis, demonstrating a statistically significant increase in odds of hypertension with the ACE D/D genotype (OR: 2.09; 95% CI: 1.24-2.91). Conspicuously, subgroup analysis by gender did not change this pattern of results. Albeit the allele distribution resulted in a higher frequency of the D/D genotype in the cases than controls, testing genetic equilibrium between the observed and expected genotypes using Hardy-Weinberg equilibrium showed ACE gene variants were confirming to the law in hypertensive as well as in non-hypertensive participants. I/D polymorphism in the angiotensin-I-converting enzyme gene at the 16th intron can be useful for outcome predictions during diagnostic processes can be implicated in an individual's propensity for hypertension and thus implies that genetic variants of ACE I/D might serve as a predictor for the susceptibility to hypertension.

The association between angiotensin II type 1 receptor A1166C gene polymorphism and the risk of essential hypertension: a meta-analysis

Background

Since first reported having the association with essential hypertension, angiotensin II type 1 receptor (AT1R) A1166C was globally investigated worldwide. However, controversy was found. Furthermore, previous meta-analyses did not adequate to clarify the precise correlation due to some limitations. Therefore, we aimed to perform a meta-analysis concerning the association between AT1R A1166C single-nucleotide polymorphism (SNP) and the risk of essential hypertension with eliminating the limitations of previous studies.

Methods

A meta-analysis was conducted from February to March 2019. Some information related to sample size of hypertension and control groups and genotype frequencies of hypertension and control groups were extracted from each study. Data were analyzed using fixed or random effect model to determine the overall correlation.

Results

A total of 45 papers consisting of 11911 cases and 1340 controls were enrolled for the study. Our overall analysis showed that C allele and AC genotype of AT1R A1166C was associated with 1.18-fold and 1.15-fold respectively increased risk of essential hypertension, while the decreased risk of essential hypertension was observed in A allele and AA genotype. In sub-group analysis, increased risk of essential hypertension was found in C allele, AC genotype, and CC genotype of both Asian population and PCR-RFLP sub-groups, while decreased risk was observed in A allele and AA genotype.

Conclusions

Our meta-analysis reveals that AT1R A1166C remains a valuable SNP having an association with the risk of essential hypertension.

Association of DD genotype of angiotensin-converting enzyme gene (I/D) polymorphism with hypertension among a North Indian population

Hypertension, a major risk factor for cardiovascular diseases, is among the leading causes of morbidity and mortality worldwide. Genetic predisposition to the risk of developing hypertension due to angiotensin-converting enzyme (ACE) gene insertion(I)/deletion(D) polymorphism (through altered serum ACE activity) is well documented among various populations. The present study investigated the possible association between ACE (DD) genotype and hypertension using a nested case-control study design including 451 individuals (of either sex in the age group 30-65 years) from a rural North Indian population practicing agriculture and lacto-vegetarianism. Blood Pressure was classified using JNC-7 criterion. Age- and sex-matched individuals were selected from normotensive (N-122), pre-hypertensive (N-123), hypertensive not on medication (N-122), and hypertensive on medication (N-84) categories. Amplification of DNA and genotyping of PCR product was done using standard protocols. From the analysis, comparatively higher frequency of individuals with DD genotype in the hypertensive category was observed, indicating a possible relation between DD genotype and hypertension. The odds ratio analysis revealed 2.225 (1.13-4.37)-fold significant increased risk for hypertension among cases, validating the vulnerability of individuals with DD genotype towards hypertension. Thus, the present study highlights the increased risk for developing hypertension due to ACE DD genotype in the studied population.

A1166C polymorphism of the angiotensin II type 1 receptor gene contributes to hypertension susceptibility: evidence from a meta-analysis

Background The angiotensin II type 1 receptor (AT1R) gene is a prime candidate for polymorphisms that could contribute to hypertension. A polymorphism in the 3' untranslated region, leading to the transversion of adenine to cytosine at position 1166, has been the most-studied variant. However, the results have been inconsistent, and we therefore performed a meta-analysis to evaluate the association of this polymorphism with hypertension. Methods We conducted an extended a computer-based literature search of PubMed and Web of Knowledge up to November 30, 2015. The extracted data were analysed statistically, and pooled odds ratios with 95% confidence intervals were calculated to assess the strengths of associations using Review Manager software (version 5.2). Results After removing 5 studies that were not consistent with the Hardy-Weinberg equilibrium, we finally collected 41 case-control studies involving 11,837 cases and 11,020 controls to evaluate the association between AT1R polymorphisms and hypertension. We found that the risk of hypertension was higher for allele C than for allele A under the codominant model, significantly higher for genotype CC + AC than for genotype AA under the dominant model, and significantly higher for genotype CC + AC in Caucasians. Conclusion This meta-analysis suggests that the AT1R 1166 CC + AC genotype consistently confers susceptibility to hypertension and that early preventive measures should be applied in clinical settings according to patient genotypes.

Association of angiotensin converting enzyme gene insertion/deletion polymorphism with essential hypertension in south Indian population

Genetic, environmental and demographic factors contribute to the development of essential hypertension. Genetic polymorphism of Rennin-angiotensin-aldosterone system (RAAS) has been extensively studied to determine the genetic susceptibility to hypertension. The insertion/deletion (I/D) angiotensin converting enzyme (ACE) polymorphism has been established as a cardiovascular risk factor in some population, but its association with essential hypertension is controversial. This study sought to determine the association of I/D polymorphism of the ACE gene in south Indian essential hypertensive subjects. A total of 208 clinically diagnosed essential hypertensive patients without any associated diseases and 220 healthy control subjects were included in this study. Distribution and allelic frequency of Insertion (I) and Deletion (D) polymorphism at the 287 base pair Alu repeat sequence in the intron 16 of ACE gene were analyzed. The distribution of II, ID, DD genotypes of ACE gene was 28.3%, 32.6% and 38.9% respectively in essential hypertensive patients and to 53.6%, 26.3% and 20% in controls. The allele frequency for D allele is 0.58 in essential hypertension as compared to 0.34 of control subjects. The genotype and allele frequency of ACE gene polymorphism is significantly differed in patients when compared to controls. In conclusion, the I/D polymorphism of ACE gene is associated with Indian essential hypertension.

Correlation between renin-angiotensin system gene polymorphisms and essential hypertension in the Chinese Yi ethnic group

INTRODUCTION

The renin-angiotensin system (RAS) has been considered to play an important role in the regulation of blood pressure. This study aimed to investigate the correlation between RAS gene polymorphisms and essential hypertension (EH) in the Chinese Yi ethnic group.

MATERIALS AND METHODS

A total of 244 EH subjects and 185 normotensive individuals from the Chinese Yi ethnic group were genotyped for AGT M235T (rs699), AT1R A1166C (rs5186), ACE I/D (rs4340) and ACE G2350A (rs4343) polymorphisms by the polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method.

RESULTS

Significant differences in the allele and genotype frequency of ACE G2350A were observed between the EH cases and controls (p=0.001, 0.002). After being grouped by gender, significant differences in the allele and genotype frequency of ACE G2350A and AT1R A1166C were observed between females of the EH cases and controls (ACE G2350A: p=0.000, 0.002; AT1R A1166C: p=0.008, 0.011). After excluding the influence of multifactorial interactions, the ACE G2350A polymorphism is significantly associated with the pathogenesis of EH in the Chinese Yi ethnic group (odds ratio (OR)=1.656, 95% confidence interval (CI) 1.807-2.524, p=0.019).

CONCLUSIONS

The RAS-related ACE G2350A polymorphism is associated with the pathogenesis of EH in the Chinese Yi ethnic group.

Polymorphisms within angiotensin II receptor type 1 gene associated with essential hypertension in Chinese Hani and Yi minorities

INTRODUCTION

Angiotensin II receptor type 1 mediates the major cardiovascular effects of angiotensin II to regulate blood pressure. Polymorphisms of angiotensin II receptor type 1 are associated with essential hypertension, but the results are inconsistent and conflicting. The aim of the present study is to assess the association between angiotensin II receptor type 1 polymorphisms and essential hypertension risk in Chinese Hani and Yi minorities.

METHODS

This study recruited 692 unrelated Chinese Hani subjects (case vs. control = 346:346) and 615 unrelated Chinese Yi subjects (case vs. control = 303:312). Twelve selected single nucleotide polymorphisms in the angiotensin II receptor type 1 gene were genotyped using a polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

Statistical analysis indicated that the GC+CC genotype of rs387967 was significantly associated with the decreased susceptibility to essential hypertension compared with GG in a Yi population (odds ratio = 0.58, 95% confidence intervals 0.41-0.83, P = 0.003). Allele C was a protective allele for essential hypertension (odds ratio = 0.78, 95% confidence intervals 0.61-0.99, P = 0.040). This association was confirmed respectively by comparing systolic blood pressure and diastolic blood pressure between different genotypes and between different alleles, which indicated that the genotype (GC+CC) had a tendency of lower systolic blood pressure and diastolic blood pressure than GG (PSBP = 3.716 × 10(-4), PDBP = 1.187 × 10(-3)); Carriers with C had lower systolic blood pressure and diastolic blood pressure (PSBP = 7.301 × 10(-3), PDBP = 9.142 × 10(-4)). Another single nucleotide polymorphism (rs2638360) was analysed in a Hani minority, then replicated in a Yi minority. The C allele showed a consistent risk trend for essential hypertension in two independent populations (Hani: odds ratio = 1.74, 95% confidence intervals 1.01-2.99, P = 0.046; Yi: odds ratio = 1.27, 95% confidence intervals 0.82-1.96, P = 0.277). Meta-analysis revealed that the C allele could significantly increase the risk of essential hypertension (odds ratio = 1.44, 95% confidence intervals 1.02-2.02, P = 0.037).

CONCLUSION

Our findings suggest that rs387967 is associated with the susceptibility to essential hypertension in a Yi population and the tendency was replicated in systolic blood pressure and diastolic blood pressure detection. Meta-analysis revealed that C allele of rs2638360 could significantly increase the risk of essential hypertension. The two single nucleotide polymorphisms maybe play a role in the pathology of essential hypertension.

Angiotensin-converting enzyme gene polymorphisms and hypertension in occupational noise exposure in Egypt

BACKGROUND

The gene-environment interaction in the pathogenesis of hypertension has not been extensively studied in occupational noise.

OBJECTIVES

The aim of this study was to determine the relationship between noise and hypertension in Egyptian workers, the interaction of angiotensin-converting enzyme (ACE) gene polymorphisms as modifiers, and the possible relationship between noise hearing impairment and hypertension.

METHODS

Study subjects were divided into two groups depending on noise exposure level. The control group (n = 161) was exposed to noise intensity <85 dB and the exposed group (n = 217) was exposed to noise intensity ≧85 dB. A polymerase chain reaction was used to differentiate the various genotypes of ACE insertion/deletion (I/D) and ACE G2350A.

RESULTS

Noise significantly increased the likelihood of hypertension. Carriers of the genotypes AG, GG, and DD were vulnerable to hypertension on noise exposure. No association between hypertension and hearing impairment or noise-induced hearing loss (NIHL) was found.

CONCLUSION

Our results support the association between ACE gene polymorphisms and occurrence of hypertension in noise-exposed workers.

Gender specific association of RAS gene polymorphism with essential hypertension: a case-control study

Renin-angiotensin system (RAS) polymorphisms have been studied as candidate risk factors for hypertension with inconsistent results, possibly due to heterogeneity among various genetic and environmental factors. A case-control association study was conducted to investigate a possible involvement of polymorphisms of three RAS genes: AGT M235T (rs699), ACE I/D (rs4340) and G2350A (rs4343), and AGTR1 A1166C (rs5186) in essential hypertensive patients. A total of 211 cases and 211 controls were recruited for this study. Genotyping was performed using PCR-RFLP method. The genotype and allele distribution of the M235T variant differed significantly in hypertensives and normotensives (OR-CI = 2.62 (1.24–5.76), P = 0.006; OR-CI = 0.699 (0.518–0.943), P = 0.018), respectively. When the samples were segregated based on sex, the 235TT genotype and T allele were predominant in the female patients (OR-CI = 5.68 (1.60-25.10), P = 0.002; OR-CI = 0.522 (0.330–0.826), P = 0.005) as compare to the male patients (OR-CI = 1.54 (1.24–5.76), P = 0.34; OR-CI = 0.874 (0.330–0.826), P = 0.506), respectively. For ACE DD variant, we found overrepresentation of “I”-allele (homozygous II and heterozygous ID) in unaffected males which suggest its protective role in studied population (OR-CI = 0.401 (0.224–0.718); P = 0.0009). The M235T variant of the AGT is significantly associated with female hypertensives and ACE DD variant could be a risk allele for essential hypertension in south India.

Platelet polymorphisms: frequency distribution and association with coronary artery disease in an Indian population

Platelets play a critical role in normal blood hemostasis and thrombus formation in myocardial infarction (MI). Several polymorphisms of genes involved in platelet activation and fibrinolysis have been reported to be associated with MI. The aim of the present study was to determine the frequency distribution and association of polymorphisms in these genes with coronary artery disease (CAD) among Indians. A case-control genetic association study was performed for polymorphisms in platelet glycoprotein receptors (GPIIb/IIIa [HPA1a/1b], GPIb-IX-V [VNTR], and GPIa/IIa [C807T]), fibrinogen β-chain (BclI), α-chain (Aα312), tissue plasminogen activator (tPA) [I/D] and plasminogen activator inhibitor-I (PAI-1) [4G/5G] in 473 healthy controls and 446 patients with stable and unstable angina. Genotyping was either by PCR-based restriction endonuclease digestion or allele-specific primers. The I allele frequency of the tPA I/D polymorphism was significantly higher in our patients (χ(2)=7.33, P<0.01) and no other polymorphisms varied significantly between patients and controls. Also, none of the polymorphisms seemed to affect the severity of the disease, the only exception being the mutant alleles of β chain of fibrinogen gene, which were significantly elevated in single vessel disease. This is the first study to evaluate the role of gene polymorphisms in both the thrombotic and fibrinolytic pathway in the Indian population and suggests that tPA I/D polymorphism confers CAD risk in our population.

Angiotensin II type 1 receptor gene polymorphism in myocardial infarction patients

Introduction. Acute myocardial infarction is commonly known as heart attack. It is a multifactorial disease influenced by environmental and genetic factors.The objective of the present study was to investigate the association of the angiotensin II type 1 receptor gene A/C polymorphism in South Indian myocardial infarction patients.

Subjects and methods. The present study included a total number of 221 subjects (107 myocardial infarction patients and 114 age- and sex-matched controls). Demographic and clinical characteristics were collected. Lipid profiles were estimated. DNA was isolated and the angiotensin II type 1 receptor gene A/C polymorphism was determined by polymerase chain reaction.

Results. Comparison of the lipid profiles between patients and controls showed that patients had statistically highly significant values (p=0.0001).The CC genotype of the angiotensin II type 1 receptor was not associated with myocardial infarction patients when compared to controls. CC vs. AA was χ2 = 2.08, odds ratio 2.30, 95% confidence interval 0.72 — 7.23, and p value was 0.14.

Conclusion. The angiotensin II type 1 receptor CC genotype is not a risk factor for myocardial infarction in patients in a South Indian population.

Angiotensin II type 1 receptor polymorphisms and susceptibility to hypertension: a HuGE review

The angiotensin II type 1 receptor (AGTR1) plays an integral role in blood pressure control, and is implicated in the pathogenesis of hypertension. Polymorphisms within this gene have been extensively studied in association with hypertension; however, findings are conflicting. To clarify these data, we conducted a systematic review of association studies of AGTR1 polymorphisms and hypertension, and performed a meta-analysis of the rs5186 variant. Results show that the currently available literature is too heterogeneous to draw meaningful conclusions. The definition of hypertension and gender composition of individual studies helps to explain this heterogeneity. Although the structure and splicing pattern of AGTR1 would suggest a likely effect of polymorphisms within the promoter region on gene function, few studies have been conducted thus far. In conclusion, there is insufficient evidence that polymorphisms in the AGTR1 gene are risk factors for hypertension. However, most studies are inadequately powered, and larger well-designed studies of haplotypes are warranted.

Influence of the Angiotensin II Type I Receptor Gene 1166A > C Polymorphism on BP and Aortic Pulse Wave Velocity Among Malays

Angiotensin II type 1 receptor (AGT1R) gene 1166A > C polymorphism has been shown to be associated with essential hypertension and aortic stiffness as measured by carotid femoral pulse wave velocity (PWV). This study was carried out to investigate the association of the 1166A > C polymorphism with blood pressure (BP) and PWV among Malay hypertensive and normotensive subjects. Two hundred and one hypertensive subjects without evidence of cardiovascular (CV) complications and 201 age- and sex-matched normotensive subjects were studied in a cross-sectional design. Blood pressures (BP) and PWV were measured, and 1166A > C genotype was determined by polymerase chain reaction followed by restriction enzyme digestion. The 1166C allele frequency was 7.96% and 7.73% among Malay hypertensive and normotensive subjects, respectively. There was no association of the 1166A > C polymorphism with BP in the hypertensive, normotensive or overall Malay populations. PWV was significantly higher among 1166C allele carriers as compared to non-carriers (10.52 +/- 1.82 vs. 10.15 +/- 1.80, p = 0.040) in the overall population, but not in the hypertensive and normotensive populations separately. In conclusion, the frequency of 1166C polymorphism is similar among Malay hypertensive and normotensive subjects. This polymorphism has no association with BP but may have an influence on PWV in Malays, which needs further investigation.

Genetics of human hypertension

Hypertension is a complex genetic disorder caused by interplay between several "risk" genes and environmental factors (genetic heritability approximately 30%). Most genetic studies of hypertension use a candidate gene approach and two conclusions have been made: there is no association or linkage with the genes studied, or the hypertension phenotype is heterogeneous and subgroups with hypertension related to certain polymorphisms cannot be identified because of background noise. Studies using intermediate phenotypes suggest the latter is most likely. Another problem is the reliability of gene structure assessment: usually only one or two gene polymorphisms are assessed. The use of intermediate phenotypes and dense mapping of candidate genes would provide a better approach for identifying genotype-phenotype correlations, which might enable the use of genotypes to identify more-specific therapeutic and preventative measures for hypertensives.

Angiotensin-converting enzyme gene polymorphism interacts with left ventricular ejection fraction and brain natriuretic peptide levels to predict mortality after myocardial infarction

OBJECTIVES

The goal of this study was the exploration of the associations between the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and post-myocardial infarction (MI) outcomes, especially any interaction with the accepted clinical prognostic markers brain natriuretic peptide (BNP) and left ventricular ejection fraction (LVEF).

BACKGROUND

The ACE gene I/D polymorphism has been implicated in the development of MI, hypertension, and left ventricular hypertrophy. We examined the association of ACE I/D and prognosis after acute MI.

METHODS

Patients incurring acute MI were genotyped for the ACE I/D polymorphism. Clinical data included assays of neurohormones, radionuclide ventriculography, and mortality over a mean 2.6 years of follow-up.

RESULTS

Patients (n = 978) had a mean age of 62.1 years, and 78% were male. Overall genotype frequencies were II 23.2%, ID 49.5%, and DD 27.3%. Chi-square analysis revealed an association between the ACE D allele and death after MI (88 of 103 who died were DD or ID; p < 0.05), with an odds ratio for mortality of 8.03 (95% confidence interval, 2.16 to 29.88). Patients with the DD genotype had higher (p < 0.05) plasma BNP, N-terminal BNP (N-BNP), and endothelin-1 levels within 96 h after MI than grouped ID/II patients. Multivariate analysis indicated ACE genotype, age, and previous MI were independent predictors of death (p < 0.05). Patients with an ACE D allele in combination with either a lower than median LVEF or greater than median BNP had a higher mortality (p < 0.001 and p < 0.025, respectively) than the risk associated with the D allele itself.

CONCLUSIONS

Angiotensin-converting enzyme genotyping may provide additional prognostic information in patients after MI in combination with the proven utility of LVEF, plasma BNP, and N-BNP measurements.

Coronary heart disease, hypertension, and angiotensinogen gene variants in Indian population

Gene encoding components of the renin angiotensin system (RAS) have been implicated with the increased risk of cardiovascular disease (CVD). Two variants of the angiotensinogen (AGT) gene, M235T and T174M, have been shown to be associated with increased risk of hypertension. In the present study, we examined the association of these two polymorphisms and their synergistic interaction with the angiotensin I-converting enzyme (ACE) deletion homozygote genotype (D/D) on subjects with coronary heart disease (CHD) and hypertension. We studied 131 healthy individuals, 141 angiographically verified CHD patients, and 159 hypertensive subjects. The identification of the ACE and AGT gene polymorphisms was carried out using a PCR-based restriction endonuclease digestion method. There was no significant difference in the distribution of the M235T and T174M variants between the two test groups and the control group. Association was also not seen when analysis was carried out in patients when subgrouped according to the extent of the severity of the disease. In addition, the risk was not restricted to subjects carrying the D allele of the ACE gene and T235T of AGT. M235T and T174M variants do not contribute to the increased risk of CHD or hypertension in the Indian population.

Gene polymorphism and coronary risk factors in Indian population

Asian Indians who have settled overseas and those in urban India have increased risk of coronary events. Reasons for this increased risk are thought to be genetic but are yet unclear. Advances in molecular cardiology have revealed a number of single nucleotide polymorphisms associated with atherosclerosis. In this review, gene polymorphisms that have been associated with coronary diseases among Indians are discussed. Topics include the genes involved in hyperlipidemia, hypertension, and homocysteine. Mutations in the low-density lipoprotein receptor (LDLR) gene resulting in familial hypercholesterolemia have strong association with premature atherosclerosis. Common polymorphism of the apolipoproteins (apo) B-100 and E genes have been associated with variation in lipid and lipoprotein levels. Recently identified polymorphisms in the apoC3 (T-455C, C-482T), and cholesteryl ester transfer protein (CETP) (B1/B2 allele) genes are associated with increased triglycerides and reduced high-density lipoprotein (HDL)-levels, a feature now also common among Asian Indians. Angiotensin-converting enzyme-deletion (DD) polymorphism has been shown to influence beta-blocker therapy in heart failure. Mutations in methylenetetrahydrofolate reductase (C667T), cystathionine beta-synthase (T833C), and methionine synthase (A2756G) genes cause hyperhomocysteinemia, an independent risk factor for atherothrombosis. As the genetics of atherosclerosis continues to evolve, these factors along with the newer emerging factors may become a part of the routine assessment, aiding prediction of future coronary events.

Genes of renin angiotensin system and coronary heart disease

Coronary constriction, proliferation of smooth muscle cells and arrhythmia are involved in the pathophysiology of coronary heart disease and its complications such as myocardial infarction and sudden death. All these effects are favoured by high angiotensin II levels. Angiotensin II is the main effector molecule of the renin angiotensin system and it acts through angiotensin II type receptors. Genetically determined differences in the expression of the components of this system could adversely affect angiotensin II concentration and subsequently heart. Consequently each component of this system represents a potential candidate in the etiology of cardiovascular disease. In this article we review the variation of the angiotensin I converting enzyme, angiotensin II type I receptor and angiotensinogen genes and their association with cardiovascular disease.