Polymorphisms of renin-angiotensin-aldosterone system gene in chinese han patients with nonfamilial atrial fibrillation

No Association Between AGT Gene Polymorphisms with Hypertension in a South African Population

Purpose

Hypertension is a leading cause of cardiovascular-related morbidity and mortality worldwide, with a prevalence increasing at an alarming rate in both middle- and low-income countries. Various environmental and genetic factors have been attributed to play a significant role in the increasing prevalence of hypertension. Single nucleotide polymorphisms (SNPs) in the angiotensinogen (AGT) gene are reported to have a significant association with hypertension; however, there are limited studies done on South African populations. Therefore, this case-control study aimed to investigate the association between AGT SNPs (rs2004776, rs3789678, rs5051 and rs7079) with hypertension in a study population of isiXhosa-speaking participants from the Eastern Cape Province in South Africa.

Materials and Methods

The SNPs were genotyped in 250 hypertensive cases and 237 normotensive controls, using TaqMan genotyping assays.

Results

For the SNP rs2004776, the frequency of CC genotype (18.4%) and C allele (44%) in hypertensive cases showed no significant differences (p = 0.52, χ2 = 1.32), when compared to the normotensive control group (CC: 19.8% and C allele: 43%). Similar results were obtained for the genotypic and allelic frequencies between hypertensive cases and normotensive controls for rs3789678 (p = 0.88, χ2=0.26) and rs5051 (p = 0.57, χ2=1.12), and rs7079 (p = 0.33, χ2=2.23). These findings demonstrate that there were no significant associations between the SNPs rs2004776, rs3789678, rs7079, rs5051 with hypertension in our study population.

Conclusion

These findings suggest that AGT gene polymorphisms are not associated with the development of hypertension in the studied population. The present study represents the first genetic report to investigate the AGT gene polymorphisms with hypertension in an isiXhosa-speaking South African population.

Aldosterone and cardiovascular diseases

Aldosterone's role in the kidney and its pathophysiologic actions in hypertension are well known. However, its role or that of its receptor [minieralocorticoid receptor (MR)] in other cardiovascular (CV) disease are less well described. To identify their potential roles in six CV conditions (heart failure, myocardial infarction, atrial fibrillation, stroke, atherosclerosis, and thrombosis), we assessed these associations in the following four areas: (i) mechanistic studies in rodents and humans; (ii) pre-clinical studies of MR antagonists; (iii) clinical trials of MR antagonists; and (iv) genetics. The data were acquired from an online search of the National Library of Medicine using the PubMed search engine from January 2011 through June 2021. There were 3702 publications identified with 200 publications meeting our inclusion and exclusion criteria. Data strongly supported an association between heart failure and dysregulated aldosterone/MR. This association is not surprising given aldosterone/MR's prominent role in regulating sodium/volume homeostasis. Atrial fibrillation and myocardial infarction are also associated with dysregulated aldosterone/MR, but less strongly. For the most part, the data were insufficient to determine whether there was a relationship between atherosclerosis, stroke, or thrombosis and aldosterone/MR dysregulation. This review clearly documented an expanding role for aldosterone/MR's dysregulation in CV diseases beyond hypertension. How expansive it might be is limited by the currently available data. It is anticipated that with an increased focus on aldosterone/MR's potential roles in these diseases, additional clinical and pre-clinical data will clarify these relationships, thereby, opening approaches to use modulators of aldosterone/MR's action to more precisely treat these CV conditions.

Tetra-ARMS-PCR assay development for genotyping of AGT rs699 T/C polymorphism, its comparison with PCR-RFLP and application in a case-control association study of cardiovascular disease patients

Genetic variations in the AGT gene play a significant role in controlling the plasma concentration of angiotensinogen (precursor protein of bioactive octapeptide angiotensin II) and the efficacy of antihypertensive drugs. In the current study, Tetra-Amplification Refractory Mutation System-Polymerase Chain Reaction (T-ARMS-PCR) was developed for genotyping of AGT rs699 T/C polymorphism and validated through Sanger DNA sequencing. Its efficiency was also tested using 474 human DNA samples [control, n = 181; cardiovascular disease (CVD) patients, n = 293]. Results showed that T-ARMS-PCR is superior to the commonly used PCR-Restriction Fragment Length Polymorphism (PCR-RFLP). Statistical analysis revealed that the AGT rs699 CC genotype is more prevalent in the CVD patient group (37% vs. 28%) and AGT rs699 C allele and CC genotype increased the risk of CVD by 1.4 and 1.9 fold, respectively. In summary, T-ARMS-PCR is the most suitable approach for quick and efficient genotyping of AGT rs699 T/C polymorphism in a large population in resource-limited countries, Furthermore, AGT rs699 T/C polymorphism is associated with the risk of CVD in the Punjabi Pakistani population.

Relationship between M235T and T174M polymorphisms in angiotensin gene and atrial fibrillation in Uyghur and Han populations of Xinjiang, China

OBJECTIVE

To elucidate the association between angiotensin gene (AGT) M235T and T174M genetic polymorphisms in Han and Uyghur patients with atrial fibrillation (AF) in Xinjiang, China.

METHODS

100 cases of patients with AF of Han and 100 cases of patients with AF of Uyghur were selected as the experimental group, and 100 cases of patients with non-AF of Uyghur and non-AF of Han were selected as the control group. We amplified the AGT M235T site and AGT T174M site by PCR in 4 groups of patients, verified the polymorphism of the sites by gene sequencing, and compared their differences in each group.

RESULTS

The high risk factors for AF such as sex, left atrial diameter (LAD), right atrial diameter (RAD), and coronary heart disease were significantly different between the Han case group and the control group (P < 0.05). There were significant differences in age, LAD, RAD, coronary heart disease and smoking as contributors to AF between Uyghur case group and control group (P < 0.05). The genotype frequency distribution of AGT M235T and AGT T174M loci in the AF group and control group of Han and Uyghur was in accordance with Hardy-Weinberg equilibrium law test. There was a significant difference in genotype frequency and allele frequency of AGT M235T locus between Han group, Uyghur AF group and control group (P < 0.05).

CONCLUSION

The AGT M235T and AGT T174M loci were associated with the occurrence of atrial fibrillation in the Han and Uyghur ethnic groups in Xinjiang.

The Genetic Puzzle of Familial Atrial Fibrillation

Atrial fibrillation (AF) is the most common clinical tachyarrhythmia. In Europe, AF is expected to reach a prevalence of 18 million by 2060. This estimate will increase hospitalization for AF to 4 million and 120 million outpatient visits. Besides being an independent risk factor for mortality, AF is also associated with an increased risk of morbidities. Although there are many well-defined risk factors for developing AF, no identifiable risk factors or cardiac pathology is seen in up to 30% of the cases. The heritability of AF has been investigated in depth since the first report of familial atrial fibrillation (FAF) in 1936. Despite the limited value of animal models, the advances in molecular genetics enabled identification of many common and rare variants related to FAF. The importance of AF heritability originates from the high prevalence of lone AF and the lack of clear understanding of the underlying pathophysiology. A better understanding of FAF will facilitate early identification of people at high risk of developing FAF and subsequent development of more effective management options. In this review, we reviewed FAF epidemiological studies, identified common and rare variants, and discussed their clinical implications and contributions to developing new personalized therapeutic strategies.

Validation study of susceptibility loci for esophageal squamous cell carcinoma identified by GWAS in a Han Chinese subgroup from Eastern China

Esophageal squamous cell carcinoma (ESCC) occurs at a relatively high frequency in China and is one of the most prevalent cancers in the world. Genome-wide association studies (GWAS) have identified 24 single-nucleotide polymorphisms (SNPs) that could be associated with ESCC in Chinese patients. This retrospective study aimed to validate the association between these 24 SNPs and ESCC in a Han Chinese subgroup from East China. A total of 2280 and 1900 patients with ESCC (case group) and non-esophageal cancer (control group) were included from a single center. Genotyping of the 24 polymorphisms was performed using the Sequenom MassARRAY system. Unconditional logistic regression analyses were conducted for every polymorphism. It was found that rs12188136 (P=0.027, OR=1.158, 95% CI=1.016-1.319 for AG/AA) was associated with ESCC. Binary logistic regression analyses revealed a significant negative association of rs875339 in RORA (P=0.014, OR=0.762, 95% CI=0.613-0.947 for TT/CC). Under the dominant model, rs6854472 was slightly associated with ESCC risk (P=0.048, OR=1.192, 95% CI=1.002-1.418). Under the recessive model, a significant negative association was observed for rs875339 (P=0.010, OR=0.758, 95% CI=0.615-0.935). In a word, this large-scale replication study validated that rs12188136 and rs6854472 are associated with ESCC in a Han Chinese subgroup from Eastern China, and that rs875339 is negative associated with ESCC.

Genomics of Atrial Fibrillation

Atrial fibrillation (AF) is a common clinical arrhythmia that appears to be highly heritable, despite representing a complex interplay of several disease processes that generally do not manifest until later in life. In this manuscript, we will review the genetic basis of this complex trait established through studies of familial AF, linkage and candidate gene studies of common AF, genome wide association studies (GWAS) of common AF, and transcriptomic studies of AF. Since AF is associated with a five-fold increase in the risk of stroke, we also review the intersection of common genetic factors associated with both of these conditions. Similarly, we highlight the intersection of common genetic markers associated with some risk factors for AF, such as hypertension and obesity, and AF. Lastly, we describe a paradigm where genetic factors predispose to the risk of AF, but which may require additional stress and trigger factors in older age to allow for the clinical manifestation of AF.

Association of SCN10A Polymorphisms with the Recurrence of Atrial Fibrillation after Catheter Ablation in a Chinese Han Population

The nonsynonymous SCN10A single nucleotide polymorphism (SNP) rs6795970 has been reported to associate with PR interval and atrial fibrillation (AF) and in strong linkage disequilibrium (LD) with the AF-associated SNP rs6800541. In this study, we investigated whether rs6795970 polymorphisms are associated with AF recurrence after catheter ablation. A total of 502 consecutive patients with AF who underwent catheter ablation were included. AF recurrence was defined as a documented episode of any atrial arrhythmias lasting ≥30 s after a blanking period of 3 months. AF recurrence was observed between 3 and 12 months after catheter ablation in 24.5% of the patients. There was a significant difference in the allele distribution (p = 7.86 × 10⁻⁵) and genotype distribution (p = 1.42 × 10⁻⁵) of rs6795970 between the AF recurrence and no recurrence groups. In a multivariate analysis, we identified the following independent predictors of AF recurrence: the rs6795970 genotypes in an additive model (OR 0.36, 95%CI 0.22~0.60, p = 7.04 × 10⁻⁵), a history of AF ≥36 months (OR 3.57, 95%CI 2.26~5.63, p = 4.33 × 10⁻⁸) and left atrial diameter (LAD) ≥40 mm (OR 1.85, 95%CI 1.08~3.19, p = 0.026). These data suggest that genetic variation in SCN10A may play an important role in predicting AF recurrence after catheter ablation in the Chinese Han population.

Risk given by AGT polymorphisms in inducing susceptibility to essential hypertension among isolated populations from a remote region of China: A case-control study among the isolated populations

INTRODUCTION

Hypertension is a serious risk factor affecting up to 30% of the world's population with a heritability of more than 30-50%. The aim of this study was to investigate the contribution of the polymorphisms localized in the angiotensinogen (AGT) gene, a main component of the renin-angiotensin-aldosterone system, in inducing the susceptibility to essential hypertension (EH) among isolated populations (Yi and Hani minorities) with low prevalence rate from the remote region of Yunnan in China.

METHODS

A case-control association study was performed, and all subjects were genotyped for the seven single nucleotide polymorphisms localized in the AGT region by polymerase chain reaction-restriction fragment length polymorphism analysis.

RESULTS

Three polymorphisms, i.e. rs5046, rs5049, and rs2478544, were significantly associated with EH among the Hani minority. The associations, found in the Yi minority, did not reach a conclusive level of statistical significance. The polymorphisms of rs2478544 and rs5046 caused the transformations of exonic splicing enhancer sites and transcription factor binding sites, respectively, in the bioinformatic analyses. The haplotype-rs5046T, rs5049A, rs11568020G, rs3789679C, rs2478544C was susceptible for EH among the Hani minority.

CONCLUSION

Our findings suggested that the AGT polymorphisms have played a vital role in determining an individual's susceptibility to EH among the isolated population, which would be helpful for EH management in the remote mountainous region of Yunnan in China.