Relationship between -344T/C polymorphism in the aldosterone synthase gene and atrial fibrillation in patients with essential hypertension

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.

Contribution of the ACE (rs1799752) and CYP11B2 (rs1799998) Gene Polymorphisms to Atrial Fibrillation in the Tunisian Population

BACKGROUND

This study investigated the association of angiotensin-converting enzyme (ACE I/D) and aldosterone synthase (CYP11B2-344C/T) gene polymorphisms in the renin-angiotensin-aldosterone system (RAAS) with atrial fibrillation (AF) in the Tunisian population.

MATERIALS AND METHODS

The study population included 120 patients with AF and 123 age-matched controls. Genotyping of the I/D polymorphism in the ACE gene and the -344C/T polymorphism in the CYP11B2 gene was performed by polymerase chain reaction (PCR) and PCR-RFLP methods, respectively.

RESULTS

The genotype distribution of the ACE I/D and CYP11B2-344C/T polymorphisms was significantly different between AF patients and control participants (p < 0.01 and p < 0.006 respectively). In addition, ACE I/D increased the risk of AF significantly by 3.41-fold for the DD genotype (OR = 3.41; 95% CI [1.39-8.34]; p < 0.007), and after adjusting for confounding factors (age, diabetes, hypertension, and dyslipidemia), the risk was higher (OR = 5.71; 95% CI [1.48-21.98]; p < 0.01). Likewise, the CYP11B2-344C/T polymorphism increased the incidence of AF for the TT genotype (OR = 3.66; 95% CI [1.62-8.27]; p < 0.002) and the CT genotype (OR = 2.68; 95% CI [1.22-5.86]; p < 0.01). After adjusting for confounding factors (age, diabetes, hypertension and dyslipidemia), the risk remained higher for the TT genotype (OR = 3.58; 95% CI [1.08-11.77]; p < 0.03). Furthermore, the haplotype-based association of the ACE I/D and CYP11B2-344C/T polymorphisms showed that the D-T haplotype increased the risk for AF.

CONCLUSION

Our study suggests a significant association of the ACE (I/D) and CYP11B2-344C/T polymorphisms with AF in the Tunisian population.

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 the -344T/C polymorphism in aldosterone synthase gene promoter with left ventricular structure in Chinese Han: A meta-analysis

No consensus view has been published on the relationship between the aldosterone synthase gene (CYP11B2) -344C/T polymorphism and left ventricular hypertrophy (LVH) in Chinese Han. We undertook a meta-analysis to investigate the potential association of this polymorphism and left ventricular structure-related phenotypes, including left ventricular mass (LVM), left ventricular mass index (LVMI), left ventricular end systolic diameter (LVESD), left ventricular end diastolic dimension (LVEDD), left ventricular posterior wall thickness (LVPWT), and interventricular septal wall thickness (IVS). Studies in English and Chinese were found based on a systematic search of Medline, Embase, CNKI, and Wanfang databases. The dominant model (TT vs. TC+CC) and homozygote model (TT vs. CC) were selected to examine the association between the -344C/T polymorphism and LVH. The random-effects model was used to pool data. From a total of 3104 participants, despite the investigation of six echocardiographic indicators, we found no significant association between the -344C/T variant and LVH in the whole group and the subgroup analyses by blood pressure. However, in the subgroup of northern Han Chinese, TT genotype had higher LVPWT than CC genotype and TC genotype (p_{heterogeneity} = 0.4, p_value = 0.04, 95% CI 0.09 (0.00, 0.18)). In addition, no evidence of publication bias was observed. In conclusion, our meta-analysis indicated that subjects with TT genotype might have higher risk of developing LVH in northern Han Chinese.

Relationship between CYP11B2-344T>C polymorphsim and atrial fibrillation: A meta-analysis

INTRODUCTION

The aldosterone synthase (CYP11B2)-344T>C gene polymorphism has been reported to influence the risk of atrial fibrillation (AF) in many studies; however, the results remain controversial and ambiguous.

MATERIALS AND METHODS

We therefore carried out a meta-analysis of published case-control studies to investigate the association between CYP11B2-344T>C polymorphism and AF susceptibility. Electronic searches were conducted on links between this variant and AF in several databases. Odds ratios (ORs) and 95% confidence intervals (CIs) for homozygous, dominant model, recessive model and allele were calculated to estimate the strength of associations in fixed and random effect models. Heterogeneity and publication bias were also assessed.

RESULTS

A total of nine case-control studies were identified. The C allele was associated with an increased susceptibility risk of AF compared with the T allele among hypertension populations (OR=1.26; 95% CI=1.09-1.45). The contrast of homozygotes and the recessive model produced the same pattern of results as the allele contrast. In the hypertension population, a significant association was found for the genetic models that were examined.

CONCLUSIONS

Our pooled data suggest a significant association exists between CYP11B2-344T>C polymorphism and AF among hypertension populations.

The Role Of Renin Angiotensin System In Atrial Fibrillation

Atrial fibrillation (AF) is the most prevalent arrhythmia and its incidence is on the rise. AF causes significant morbidity and mortality leading to rising AF-related health care costs. There is experimental and clinical evidence from animal and human studies that suggests a role for the renin angiotensin system (RAS) in the etiopathogenesis of AF. This review appraises the current understanding of RAS antagonism, using angiotensin converting enzyme inhibitors (ACE-I), angiotensin receptor blockers (ARB) and aldosterone antagonists (AA), for prevention of AF. RAS antagonism has proven to be effective for primary and secondary prevention of AF in subjects with heart failure and left ventricular (LV) dysfunction.However, most of the evidence for the protective effect of RAS antagonism is from clinical trials that had AF as a secondary outcome or from unspecified post-hoc analyses. The evidence for prevention in subjects without heart failure and with normal LV function is not as clear. RAS antagonism, in the absence of concomitant antiarrhythmic therapy, was not shown to reduce post cardioversion AF recurrences. RAS antagonism in subjects undergoing catheter ablation has also been ineffective in preventing AF recurrences.

Association of aldosterone synthase polymorphism (CYP11B2 -344T>C) and genetic ancestry with atrial fibrillation and serum aldosterone in African Americans with heart failure

The objective of this study was to examine the extent to which aldosterone synthase genotype (CYP11B2) and genetic ancestry correlate with atrial fibrillation (AF) and serum aldosterone in African Americans with heart failure. Clinical data, echocardiographic measurements, and a genetic sample for determination of CYP11B2 -344T>C (rs1799998) genotype and genetic ancestry were collected from 194 self-reported African Americans with chronic, ambulatory heart failure. Genetic ancestry was determined using 105 autosomal ancestry informative markers. In a sub-set of patients (n = 126), serum was also collected for determination of circulating aldosterone. The CYP11B2 -344C allele frequency was 18% among the study population, and 19% of patients had AF. Multiple logistic regression revealed that the CYP11B2 -344CC genotype was a significant independent predictor of AF (OR 12.7, 95% CI 1.60-98.4, p = 0.0150, empirical p = 0.011) while holding multiple clinical factors, left atrial size, and percent European ancestry constant. Serum aldosterone was significantly higher among patients with AF (p = 0.036), whereas increased West African ancestry was inversely correlated with serum aldosterone (r = -0.19, p = 0.037). The CYP11B2 -344CC genotype was also overrepresented among patients with extreme aldosterone elevation (≥90th percentile, p = 0.0145). In this cohort of African Americans with chronic ambulatory heart failure, the CYP11B2 -344T>C genotype was a significant independent predictor of AF while holding clinical, echocardiographic predictors, and genetic ancestry constant. In addition, increased West African ancestry was associated with decreased serum aldosterone levels, potentially providing an explanation for the lower risk for AF observed among African Americans.

CYP11B2 T-344C gene polymorphism and atrial fibrillation: a meta-analysis of 2,758 subjects

BACKGROUND

Aldosterone synthase (CYP11B2) T-344C gene polymorphism was found to be correlated with atrial fibrillation (AF) risk. However, the results of individual studies remain conflicting.

OBJECTIVE AND METHODS

A meta-analysis including 2,758 subjects from six individual studies was performed to explore the correlation between CYP11B2 T-344C gene polymorphisms and AF. The pooled odds ratios (ORs) and their corresponding 95% confidence intervals (95% CIs) were evaluated by the fixed- or random-effects model.

RESULTS

A significant relationship between CYP11B2 T-344C gene polymorphism and AF was found under allelic (OR: 1.26, 95% CI: 1.11-1.42, P = 0.0002), recessive (OR: 1.99, 95% CI: 1.26-3.14, P = 0.003), dominant (OR: 0.903, 95% CI: 0.820-0.994, P = 0.036), homozygous (OR: 1.356, 95% CI: 1.130-1.628, P = 0.001), and additive (OR: 1.153, 95% CI: 1.070-1.243, P = 1.0×10(-10)) genetic models. No significant association between CYP11B2 T-344C gene polymorphism and AF was found under the heterozygous genetic model (OR: 1.040, 95% CI: 0.956-1.131, P = 0.361).

CONCLUSIONS

A significant association was found between CYP11B2 T-344C gene polymorphism and AF risk. Individuals with the C allele of CYP11B2 T-344C gene polymorphism have higher risk for AF.