The influence of Angiotensin converting enzyme and angiotensinogen gene polymorphisms on hypertrophic cardiomyopathy

Exploring the impact of angiotensin-converting enzyme (ACE) gene polymorphism on early diastolic function in hypertension using four-dimensional echocardiography

BACKGROUND

This study explores the relationship between angiotensin-converting enzyme (ACE) gene polymorphisms and early diastolic dysfunction in patients with hypertension utilizing four-dimensional echocardiography and assesses the prognosis.

METHODS

This study consecutively selected 470 patients with hypertension who visited the Fourth Affiliated Hospital of Soochow University between September 2021 and August 2022, with 274 meeting the inclusion criteria. Hypertension gene testing was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques, and the Hardy-Weinberg equilibrium test was used to confirm genetic equilibrium. Patients were categorized into the D allele group (n = 163) and the non-D allele group (n = 111). Diastolic function was assessed using four-dimensional echocardiography, which included averaging the E/e' ratio over three cardiac cycles, measuring the left atrial (LA) maximum volume index (LA volume), tricuspid regurgitation velocity (TR velocity), LA strain, and left ventricular isovolumic relaxation time (IVRT). Patients were subsequently classified into the diastolic dysfunction group (n = 133) and the normal diastolic function group (n = 141). Chi-square tests were used to analyze differences in diastolic function indicators between the groups, Logistic regression was applied to control for potential confounding factors, and receiver operating characteristic (ROC) curves were plotted to assess the predictive value of different ACE alleles for diastolic dysfunction in patients with hypertension.

RESULTS

The genotype distribution in both the D allele group and the non-D allele group was consistent with Hardy-Weinberg equilibrium (P > 0.05). Compared to the non-D allele group, echocardiographic indicators in the D allele group showed a decline in diastolic function: the average E/e' ratio over three cardiac cycles (14.67 [13.82, 15.80] vs. 9.30 [8.12, 12.00]), LA volume (32.76 [29.34, 34.61] vs. 25.61 [22.63, 29.64] ml/m2), TR velocity (2.90 [2.40, 2.90] vs. 1.40 [1.10, 2.40] cm/s), LA strain (18.00 [14.00, 25.00] vs. 37.00 [24.00, 40.00] %), and IVRT (104.25 [95.87, 106.25] vs. 88.09 [80.99, 96.56] ms). Differences between each group were statistically significant (all P < 0.05). The number of patients with diastolic dysfunction was higher in the D allele group (n = 102; 62.6%) compared to the non-D allele group (n = 31; 27.9%). In the logistic regression model, the D allele was associated with an increased risk of early diastolic dysfunction in hypertension (OR = 4.32, 95% CI = 2.56-7.27, P < 0.01). In the adjusted model, the D allele remained associated with an elevated risk of early diastolic dysfunction in hypertension (OR = 3.83, 95% CI = 2.24-6.54, P < 0.01). ROC curve analysis indicated that the D allele has predictive value for early diastolic dysfunction in patients with hypertension (area under the curve [AUC], 0.667; 95% confidence interval [CI], 0.608-0.723; sensitivity, 76.7%; and specificity, 56.7%; P < 0.05).

CONCLUSIONS

The ACE-D allele is associated with early diastolic dysfunction in hypertension. ACE gene testing can enhance the predictive value for diastolic dysfunction in patients with hypertension.

Genetic Association of the Ins/Del Variant of ACE and Risk of Cardiomyopathy: A Case-Control Study and Updated Meta-Analysis

INTRODUCTION

Cardiomyopathy is a complex condition influenced by multiple genes and environmental factors. It has been suspected that cardiomyopathy is affected by the ACE gene's I/D polymorphism. Our study aimed to evaluate the association between this polymorphism and cardiomyopathy risk in the Jammu population of North India, alongside a meta-analysis to determine the specific risks associated with different types of cardiomyopathy.

METHOD

In the case-control study, we opted for a convenient sampling technique to gather patients from hospitals. Meanwhile, for the meta-analysis registered under PROSPERO with CRD42024519763, and in line with PRISMA guidelines, we accessed online databases and applied predefined inclusion criteria. Data extraction and quality assessment were performed using the Newcastle-Ottawa scale. Statistical analysis included genotypic frequencies, Hardy-Weinberg equilibrium testing, logistic regression models, and assessments for heterogeneity and publication bias.

RESULT

The case-control study revealed a significant association between the ACE I/D risk variant and cardiomyopathy risk in the Jammu population (odds ratio [OR]: 1.30, confidence interval [CI] [1.04-1.63], p value = 0.021). Furthermore, a total of 34 studies were fund-eligible for the meta-analysis and demonstrated a significant association between the risk variant and both dilated (OR: 1.25, CI [1.03-1.50], p value = 0.022) and hypertrophic (OR: 1.31, CI [1.0876-1.5776], p value = 0.004446) cardiomyopathy.

CONCLUSION

Our study found a significant association between the I/D polymorphism and cardiomyopathy risk in the Jammu population. Further, the meta-analysis strengthens the findings by consistently linking the ACE I/D polymorphism to both dilated and hypertrophic cardiomyopathy. These results underscore the importance of genetic factors in cardiomyopathy risk assessment and further research is needed to understand the underlying mechanisms and potential therapeutic implications.

Impact of the gene polymorphisms in the renin-angiotensin system on cardiomyopathy risk: A meta-analysis

Due to the inconsistent findings from various studies, the role of gene polymorphisms in the renin-angiotensin system in influencing the development of cardiomyopathy remains unclear. In this study, we conducted a systematic review and meta-analysis to summarize the findings regarding the impact of angiotensin converting enzyme (ACE) I/D, angiotensinogen (AGT) M235T, and angiotensin II Type 1 receptor (AGTR1) A1166C gene polymorphisms in patients with cardiomyopathy. We performed a comprehensive search of several electronic databases, including PubMed, Embase, the Cochrane Library, and Web of Science, covering articles published from the time of database creation to April 17, 2023. Studies on the assessment of genetic polymorphisms in genes related to the renin-angiotensin system in relation to cardiomyopathy were included. The primary outcome was cardiomyopathy. Risk of bias was assessed using the Newcastle-Ottawa Scale scale. The meta-analysis includes 19 studies with 4,052 cases and 5,592 controls. The ACE I/D polymorphisms were found to be associated with cardiomyopathy (allelic model D vs I: OR = 1.29, 95CI% = 1.08-1.52; dominant model DD+ID vs II: OR = 1.43, 95CI% = 1.01-2.02; recessive model DD vs ID+II: OR = 0.79, 95CI% = 0.64-0.98). AGT M235T polymorphism and cardiomyopathy were not significantly correlated (allelic model T vs M: OR = 1.26, 95CI% = 0.96-1.66; dominant model TT+MT vs MM: OR = 1.30, 95CI% = 0.98-1.73; recessive model TT vs MT+MM: OR = 0.63, 95CI% = 0.37-1.07). AGTR1 polymorphism and cardiomyopathy were not significantly associated under allelic model A vs C (OR = 0.69, 95CI% = 0.46-1.03) and recessive model AA vs CA+CC (OR = 0.89, 95CI% = 0.34-2.30), but under the dominant model AA+CA vs CC (OR = 0.51, 95CI% = 0.38-0.68). The current meta-analysis reveals that polymorphisms in ACE I/D may be a genetic risk factor for cardiomyopathy. There is an association between AGTR1 gene polymorphisms and risk of cardiomyopathy under the specific model.

Risk Assessment Using the Association Between Renin-Angiotensin Genes Polymorphisms and Coronary Artery Disease

Coronary artery disease (CAD) is a multifactorial disease that involves genetic and environmental interaction. In addition to the well-known CAD risk factors, such as diabetes mellitus, hypertension, hyperlipidemia, and atherosclerosis, it has a genetic component that predisposes to its occurrence even in young people. One of the most commonly studied genes that increase the susceptibility to CAD is renin-angiotensin system (RAS) genes polymorphisms mainly angiotensin-converting enzyme gene (ACE) polymorphisms, angiotensinogen polymorphisms, angiotensin- II type 1 receptor gene polymorphisms, and many other genes. These genetic polymorphisms have a direct association with CAD development or indirect association through causing atherosclerosis and hypertension which, in turn, are complicated by CAD later on. The difference between genetic mutations and polymorphisms lies in the frequency of the abnormal genotype. If the frequency is 1% and more in the general population, it is called polymorphism and if it is less than 1%, then it is called a mutation.

According to our findings, after thorough searching, which support the association of RAS genes polymorphisms with premature CAD, hypertension, hypertrophic cardiomyopathy, and atherosclerosis, we recommend additional studies in the form of clinical trials and meta-analyses aiming to create a specific diagnostic tool for CAD risk assessment and discovering the high-risk people as early as possible. Targeted gene therapy, being the future of medicine, needs to be taken into researchers' consideration. It can have promising results in these cases.

Association Between AGT M235T and Left Ventricular Mass in Vietnamese Patients Diagnosed With Essential Hypertension

Background: Increasing left ventricular mass in hypertensive patients is an independent prognostic marker for adverse cardiovascular outcomes. Genetic factors have been shown to critically affect left ventricular mass. AGT M235T is one of the genetic polymorphisms that may influence left ventricular mass due to its pivotal role in the regulation of plasma angiotensinogen level as well as hypertension pathophysiology in Asian populations. Currently, how M235T affects left ventricular mass is not well-described in Vietnamese hypertensive patients. This study aimed to investigate the association between M235T and left ventricular mass in Vietnamese patients diagnosed with essential hypertension. Materials and Methods: AGT M235T genotyping and 2D echocardiography were performed on 187 Vietnamese subjects with essential hypertension. All the ultrasound parameters were obtained to calculate the left ventricular mass index according to the American Society of Echocardiography and the European Association of Cardiovascular Imaging 2015 guidelines. Other clinical characteristics were also recorded, including age, gender, duration of hypertension, hypertensive treatment, lifestyle, renal function, fasting plasma glucose, and lipid profile. Results: MT and TT genotypes were determined in 30 and 157 subjects, respectively. AGT M235T genotype, duration of hypertension, body mass index, and ejection fraction statistically affected the left ventricular mass index, which was significantly greater in TT compared to MT carriers after adjusting for confounding factors. Conclusion: The TT genotype of AGT M23T was associated with greater left ventricular mass in Vietnamese patients diagnosed with essential hypertension.

Angiotensinogen M235T polymorphism and susceptibility to hypertrophic cardiomyopathy in Asian population: A meta analysis

OBJECTIVE

To explore the relationship between the polymorphism of angiotensinogen gene (AGT) M235T and susceptibility to hypertrophic cardiomyopathy (HCM) in Asian population by meta-analysis.

METHODS

PubMed, Embase, Web of Science, Cochrane library, CNKI, Wan Fang, and other databases were searched to collect the literature about AGT M235T polymorphism and HCM from the inception to March 1, 2020. The Newcastle-Ottawa Scale (NOS) checklist was uesd to perform independent literature review and study quality assessment. Data was analyzed by Stata 15.0 software.

RESULTS

The results showed that, except for the recessive genetic model (TT vs MT+MM: OR = 1.27, 95%CI: 1.05-1.53), in the other four genetic models, the M235T polymorphism had no significant correlation with the risk of HCM (T vs M: OR = 1.17, 95%CI: 0.88-1.57; TT+MT vs MM: OR = 1.13, 95%CI: 0.55-2.33; TT vs MM: OR = 1.25, 95%CI: 0.60-2.59; TM vs MM: OR = 0.95, 95%CI0.5-1.82). The results of subgroup analysis showed that, except for the heterozygous genetic model, in the other four genetic models, M235T polymorphism was significantly associated with sporadic hypertrophic cardiomyopathy (SHCM), but not with familial hypertrophic cardiomyopathy (FHCM) (p > 0.05).

CONCLUSION

M235T polymorphism in Asians is associated with HCM, especially SHCM. Heterozygotes increase the risk of patients with SHCM.

ALUminating the Path of Atherosclerosis Progression: Chaos Theory Suggests a Role for Alu Repeats in the Development of Atherosclerotic Vascular Disease

Atherosclerosis (ATH) and coronary artery disease (CAD) are chronic inflammatory diseases with an important genetic background; they derive from the cumulative effect of multiple common risk alleles, most of which are located in genomic noncoding regions. These complex diseases behave as nonlinear dynamical systems that show a high dependence on their initial conditions; thus, long-term predictions of disease progression are unreliable. One likely possibility is that the nonlinear nature of ATH could be dependent on nonlinear correlations in the structure of the human genome. In this review, we show how chaos theory analysis has highlighted genomic regions that have shared specific structural constraints, which could have a role in ATH progression. These regions were shown to be enriched with repetitive sequences of the Alu family, genomic parasites that have colonized the human genome, which show a particular secondary structure and are involved in the regulation of gene expression. Here, we show the impact of Alu elements on the mechanisms that regulate gene expression, especially highlighting the molecular mechanisms via which the Alu elements alter the inflammatory response. We devote special attention to their relationship with the long noncoding RNA (lncRNA); antisense noncoding RNA in the INK4 locus (ANRIL), a risk factor for ATH; their role as microRNA (miRNA) sponges; and their ability to interfere with the regulatory circuitry of the (nuclear factor kappa B) NF-κB response. We aim to characterize ATH as a nonlinear dynamic system, in which small initial alterations in the expression of a number of repetitive elements are somehow amplified to reach phenotypic significance.

Association between ACE and AGT polymorphism and cardiovascular risk in acromegalic patients

PURPOSE

Whether the renin-angiotensin-aldosterone system plays a role or not in the development of cardiovascular morbidity in acromegaly patients is unknown. The aim of the study was to investigate the association between ACE (I/D) and AGT (M235T) gene polymorphisms and cardiovascular and metabolic disorders in the acromegaly.

METHODS

The study included one hundred and seventeen acromegalic patients (62 F/55 M, age: 50.2 ± 12.3 years) and 106 healthy controls (92 F/14 M, age: 41.4 ± 11.3 years). PCR method was used to evaluate the prevalence of ACE and AGT genotype.

RESULTS

The genotypes of ACE polymorphism in acromegalic patients were distributed as follows; 41.0% (n: 48) for DD, 44.4% (n: 52) for ID and 14.5% (n: 17) for II genotype. The control group had significantly different distribution of the ACE polymorphism [48.1% (n: 51) for DD, 25.5% (n: 27) for ID and 26.4% (n: 28) for II genotype]compared to acromegalic group. Regarding AGT polymorphism, AGT-MT genotype was seen in 88.9% of the acromegalic patients while MM and TT genotype (9.4% and 1.7%, respectively) were present in the rest. The controls had similar distribution of the AGT genotype with the acromegaly group (80.2% MT genotype, 15.1% MM genotype and 4.7% TT genotype). Due to the small number of patients with TT allele (n: 2), T carriers for AGT genotype (AGT-MT+TT) were subgrouped and compared to those with AGT-MM group. ACE-DD, ID and II groups had similar anthropometric measures, blood pressure values and baseline GH and IGF-1 levels. Significantly higher baseline GH levels were found in AGT-MM group compared to T allele carriers [40 (16-60) vs. 12 (5-36) µg/L, p < 0.05]. The compared groups in both polymorphisms had similar fasting plasma glucose levels. Patients with ACE-II genotype had significantly higher HDL-C levels compared to those with ACE-DD and ACE-ID polymorphisms (p < 0.05) whereas there was no significant difference in lipid profile between AGT-MM group and AGT-T allele carriers. Moreover, the compared groups in both polymorphisms had similar distribution of hyperlipidemia, hypertension, impaired glucose metabolism (prediabetes or type 2 diabetes mellitus) and coronary artery disease. In terms of echocardiographic parameters, systolic and diastolic function was similar among the groups in ACE and AGT genotypes. Interestingly, AGT-MM group had higher mitral inflow Apeak values than T allele carriers (0.94 ± 0.46 vs. 0.73 ± 0.20; p = 0.051). No significant difference was observed in LV mass index values in acromegalic patients among the groups in both polymorphisms.

CONCLUSIONS

Both ACE (I/D) and AGT (M235T) gene polymorphisms do not seem to have a significant effect on the development of clinical properties or cardiovascular comordities of acromegalic patients.

The association of insertions/deletions (INDELs) and variable number tandem repeats (VNTRs) with obesity and its related traits and complications

BACKGROUND

Despite the fact that insertions/deletions (INDELs) are the second most common type of genetic variations and variable number tandem repeats (VNTRs) represent a large portion of the human genome, they have received far less attention than single nucleotide polymorphisms (SNPs) and larger forms of structural variation like copy number variations (CNVs), especially in genome-wide association studies (GWAS) of complex diseases like polygenic obesity. This is exemplified by the vast amount of review papers on the role of SNPs and CNVs in obesity, its related traits (like anthropometric measurements, biochemical variables, and eating behavior), and its related complications (like hypertension, hypertriglyceridemia, hypercholesterolemia, and insulin resistance-collectively known as metabolic syndrome). Hence, this paper reviews the types of INDELs and VNTRs that have been studied for association with obesity and its related traits and complications. These INDELs and VNTRs could be found in the obesity loci or genes from the earliest GWAS and candidate gene association studies, like FTO, genes in the leptin-proopiomelanocortin pathway, and UCP2/3. Given the important role of the brain serotonergic and dopaminergic reward system in obesity susceptibility, the association of INDELs and VNTRs in these neurotransmitters' metabolism and transport genes with obesity is also reviewed. Next, the role of INS VNTR in obesity and its related traits is questionable, since recent large-scale studies failed to replicate the earlier positive associations. As obesity results in chronic low-grade inflammation of the adipose tissue, the proinflammatory cytokine gene IL1RA and anti-inflammatory cytokine gene IL4 have VNTRs that are implicated in obesity. A systemic proinflammatory state in combination with activation of the renin-angiotensin system and decreased nitric oxide bioavailability as found in obesity leads to endothelial dysfunction. This explains why VNTR and INDEL in eNOS and ACE, respectively, could be predisposing factors of obesity. Finally, two novel genes, DOCK5 and PER3, which are involved in the regulation of the Akt/MAPK pathway and circadian rhythm, respectively, have VNTRs and INDEL that might be associated with obesity.

SHORT CONCLUSION

In conclusion, INDELs and VNTRs could have important functional consequences in the pathophysiology of obesity, and research on them should be continued to facilitate obesity prediction, prevention, and treatment.

Recent Advances in the Molecular Genetics of Familial Hypertrophic Cardiomyopathy in South Asian Descendants

The South Asian population, numbered at 1.8 billion, is estimated to comprise around 20% of the global population and 1% of the American population, and has one of the highest rates of cardiovascular disease. While South Asians show increased classical risk factors for developing heart failure, the role of population-specific genetic risk factors has not yet been examined for this group. Hypertrophic cardiomyopathy (HCM) is one of the major cardiac genetic disorders among South Asians, leading to contractile dysfunction, heart failure, and sudden cardiac death. This disease displays autosomal dominant inheritance, and it is associated with a large number of variants in both sarcomeric and non-sarcomeric proteins. The South Asians, a population with large ethnic diversity, potentially carries region-specific polymorphisms. There is high variability in disease penetrance and phenotypic expression of variants associated with HCM. Thus, extensive studies are required to decipher pathogenicity and the physiological mechanisms of these variants, as well as the contribution of modifier genes and environmental factors to disease phenotypes. Conducting genotype-phenotype correlation studies will lead to improved understanding of HCM and, consequently, improved treatment options for this high-risk population. The objective of this review is to report the history of cardiovascular disease and HCM in South Asians, present previously published pathogenic variants, and introduce current efforts to study HCM using induced pluripotent stem cell-derived cardiomyocytes, next-generation sequencing, and gene editing technologies. The authors ultimately hope that this review will stimulate further research, drive novel discoveries, and contribute to the development of personalized medicine with the aim of expanding therapeutic strategies for HCM.

Hypothesis and theory: mechanical instabilities and non-uniformities in hereditary sarcomere myopathies

Familial hypertrophic cardiomyopathy (HCM), due to point mutations in genes for sarcomere proteins such as myosin, occurs in 1/500 people and is the most common cause of sudden death in young individuals. Similar mutations in skeletal muscle, e.g., in the MYH7 gene for slow myosin found in both the cardiac ventricle and slow skeletal muscle, may also cause severe disease but the severity and the morphological changes are often different. In HCM, the modified protein function leads, over years to decades, to secondary remodeling with substantial morphological changes, such as hypertrophy, myofibrillar disarray, and extensive fibrosis associated with severe functional deterioration. Despite intense studies, it is unclear how the moderate mutation-induced changes in protein function cause the long-term effects. In hypertrophy of the heart due to pressure overload (e.g., hypertension), mechanical stress in the myocyte is believed to be major initiating stimulus for activation of relevant cell signaling cascades. Here it is considered how expression of mutated proteins, such as myosin or regulatory proteins, could have similar consequences through one or both of the following mechanisms: (1) contractile instabilities within each sarcomere (with more than one stable velocity for a given load), (2) different tension generating capacities of cells in series. These mechanisms would have the potential to cause increased tension and/or stretch of certain cells during parts of the cardiac cycle. Modeling studies are used to illustrate these ideas and experimental tests are proposed. The applicability of similar ideas to skeletal muscle is also postulated, and differences between heart and skeletal muscle are discussed.