Influence of gene polymorphisms of the renin-angiotensin system on clinical outcome in heart failure among the Chinese

Influence of Angiotensin-converting Enzyme Insertion/Deletion Gene Polymorphism in Progression of Chagas Heart Disease

INTRODUCTION

Chagas disease (CD) is a neglected disease caused by the parasite Trypanosoma cruzi. One-third of infected patients will develop the cardiac form, which may progress to heart failure (HF). However, the factors that determine disease progression remain unclear. Increased angiotensin II activity is a key player in the pathophysiology of HF. A functional polymorphism of the angiotensin-converting enzyme (ACE) gene is associated with plasma enzyme activity. In CD, ACE inhibitors have beneficial effects supporting the use of this treatment in chagasic cardiomyopathy.

METHODS

We evaluated the association of ACE I/D polymorphism with HF, performing a case-control study encompassing 343 patients with positive serology for CD staged as non-cardiomyopathy (stage A; 100), mild (stage B1; 144), and severe (stage C; 99) forms of Chagas heart disease. For ACE I/D genotyping by PCR, groups were compared using unconditional logistic regression analysis and adjusted for nongenetic covariates: age, sex, and trypanocidal treatment.

RESULTS

A marginal, but not significant (p=0.06) higher prevalence of ACE I/D polymorphism was observed in patients in stage C compared with patients in stage A. Patients in stage C (CD with HF), were compared with patients in stages A and B1 combined into one group (CD without HF); DD genotype/D carriers were prevalent in the HF patients (OR = 2; CI = 1.013.96; p = 0.04).

CONCLUSIONS

Our results of this cohort study, comprising a population from the Northeast region of Brazil, suggest that ACE I/D polymorphism is more prevalent in the cardiac form of Chagas disease with HF.

Determined to Fail--the Role of Genetic Mechanisms in Heart Failure

Genetic variants contribute to several steps during heart failure pathophysiology. The mechanisms include frequent polymorphisms that increase the susceptibility to heart failure in the general population and rare variants as causes of an underlying cardiomyopathy. In this review, we highlight recent discoveries made by genetic approaches and provide an outlook onto the role of epigenetic modifiers of heart failure.

Biomarkers for Heart Failure in Asia

Contributions from the Asian biomedical community to knowledge of biomarkers in heart failure have grown rapidly since 2000. Japan has made world-leading contributions in the discovery and application of cardiac natriuretic peptides as biomarkers in heart failure, but there has been rapid growth in reports from China. Contributions also come from Taiwan, South Korea, Singapore, and Hong Kong. Centers in Asia have established clinical cohorts providing powerful platforms for the discovery and validation of biomarkers in heart failure. This century, Asian enquiry into biomarkers in heart failure will include peptides, cytokines, metabolites, nucleic acids, and other analytes.

Angiotensin-converting enzyme genetic polymorphism: its impact on cardiac remodeling

BACKGROUND

The role of angiotensin-converting enzyme genetic polymorphisms as a predictor of echocardiographic outcomes on heart failure is yet to be established. The local profile should be identified so that the impact of those genotypes on the Brazilian population could be identified. This is the first study on exclusively non-ischemic heart failure over a follow-up longer than 5 years.

OBJECTIVE

To determine the distribution of angiotensin-converting enzyme genetic polymorphism variants and their relation with echocardiographic outcome of patients with non-ischemic heart failure.

METHODS

Secondary analysis of the medical records of 111 patients and identification of the angiotensin-converting enzyme genetic polymorphism variants, classified as DD (Deletion/Deletion), DI (Deletion/Insertion) or II (Insertion/Insertion).

RESULTS

The cohort means were as follows: follow-up, 64.9 months; age, 59.5 years; male sex, 60.4%; white skin color, 51.4%; use of beta-blockers, 98.2%; and use of angiotensin-converting-enzyme inhibitors or angiotensin receptor blocker, 89.2%. The angiotensin-converting enzyme genetic polymorphism distribution was as follows: DD, 51.4%; DI, 44.1%; and II, 4.5%. No difference regarding the clinical characteristics or treatment was observed between the groups. The final left ventricular systolic diameter was the only isolated echocardiographic variable that significantly differed between the angiotensin-converting enzyme genetic polymorphisms: 59.2 ± 1.8 for DD versus 52.3 ± 1.9 for DI versus 59.2 ± 5.2 for II (p = 0.029). Considering the evolutionary behavior, all echocardiographic variables (difference between the left ventricular ejection fraction at the last and first consultation; difference between the left ventricular systolic diameter at the last and first consultation; and difference between the left ventricular diastolic diameter at the last and first consultation) differed between the genotypes (p = 0.024; p = 0.002; and p = 0.021, respectively).

CONCLUSION

The distribution of the angiotensin-converting enzyme genetic polymorphisms differed from that of other studies with a very small number of II. The DD genotype was independently associated with worse echocardiographic outcome, while the DI genotype, with the best echocardiographic profile (increased left ventricular ejection fraction and decreased left ventricular diameters).

Genetic prediction of heart failure incidence, prognosis and beta-blocker response

Heart failure (HF) is a widespread syndrome due to left ventricular dysfunction with high mortality, morbidity and health-care costs. Beta-blockers, together with diuretics and ACE-inhibitors or angiotensin receptor blockers, are a cornerstone of HF therapy, as they reduce mortality and morbidity. Nevertheless, their efficacy varies among patients, and genetics is likely to be one of the modifying factors. In this article, literature on the role of candidate genes on the development of HF, its prognosis and pharmacogenomics of β-blockers in patients with HF is reviewed. The available findings do not support, at the present time, a role for genetic tests in the treatment of HF. More large-scale genome-wide studies with adequate methodology and statistical analysis are required before considering genetic tailoring of HF therapy in patients with systolic HF.

The M235T polymorphism in the angiotensinogen gene and heart failure: a meta-analysis

BACKGROUND

The aim of the present study was to assess the association between M235T polymorphism and heart failure using a meta-analysis.

METHODS

A literature search of Google Scholar, PubMed, the Cochrane Library and the China National Knowledge Infrastructure database (January 1990-April 2012) was performed for relevant studies. Statistical analyses were carried out using the Stata 12.0 to combine all the relevant studies. Summary odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated in a fixed-effects model and a random-effects model when appropriate. The pooled ORs were performed under the allelic contrast (T vs M), the dominant (TT + MT vs. MM) and the recessive models (TT vs MT + MM). Begg's test was used to measure publication bias.

RESULTS

A total of six case-control studies including 842 patients and 1054 controls were enrolled in this meta-analysis. Overall, there was a significant association between angiotensinogen (AGT) gene M235T polymorphism and risk of heart failure in the subgroup analysis under the allelic contrast (T vs M: OR = 1.48, 95% CI: 1.04-2.11) and the dominant model (TT+MT vs MM: OR=1.67, 95% CI: 1.13-2.46) in the Caucasian population.

CONCLUSIONS

The current meta-analysis suggests that M235T polymorphism might be associated with increased risk of heart failure in Caucasians.

Impact of polymorphisms in the renin–angiotensin–aldosterone system on hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a clinically heterogeneous autosomal dominant heart disease characterised by left ventricular hypertrophy in the absence of another cardiac or systemic disease that is capable of producing significant wall thickening. Microscopically it is characterised by cardiomyocyte hypertrophy, myofibrillar disarray and fibrosis. The phenotypic expression of HCM is multifactorial, with the majority of cases occurring secondary to mutations in genes encoding the sarcomere proteins. In conjunction with the genetic heterogeneity of HCM, phenotypic expression also exhibits a high level of variability even within families with the same aetiological mutation, and may be influenced by additional genetic factors. Polymorphisms of the renin–angiotensin–aldosterone system (RAAS) represent an attractive hypothesis as potential disease modifiers, as these genetic variants alter the ‘activation status’ of the RAAS, which leads to more left ventricular hypertrophy through different pathways. The main objective of this review is to provide an overview of the role of different polymorphisms identified in the RAAS, in patients with HCM.

Angiotensin-converting enzyme insertion/deletion gene polymorphism and progression of Chagas' cardiomyopathy

Chagas' disease is common in Latin America and is caused by Trypanosoma cruzi. It is usually associated with chronic cardiomyopathy, the progression of which could be related to genetic factors. As alterations in the renin-angiotensin-aldosterone system have been reported in the disease, the aim of this study was to determine whether associated genetic polymorphisms influence the development of myocardial damage. The study involved 125 patients who were divided into two groups according to whether they had mild or severe cardiomyopathy. The insertion/deletion polymorphism of the angiotensin-converting enzyme gene was investigated using standard techniques and results were correlated with disease stage. The genotypes were in Hardy-Weinberg equilibrium. After adjusting for demographic variables, no significant relationship was found between the polymorphism and progression of chronic Chagas' disease. Although our sample was limited, the results suggest that the progression of cardiomyopathy in chronic Chagas' disease is unrelated to the insertion/deletion polymorphism.

Angiotensin-converting enzyme insertion/deletion gene polymorphism and progression of Chagas' cardiomyopathy

Chagas' disease is common in Latin America and is caused by Trypanosoma cruzi. It is usually associated with chronic cardiomyopathy, the progression of which could be related to genetic factors. As alterations in the renin-angiotensin-aldosterone system have been reported in the disease, the aim of this study was to determine whether associated genetic polymorphisms influence the development of myocardial damage. The study involved 125 patients who were divided into two groups according to whether they had mild or severe cardiomyopathy. The insertion/deletion polymorphism of the angiotensin-converting enzyme gene was investigated using standard techniques and results were correlated with disease stage. The genotypes were in Hardy-Weinberg equilibrium. After adjusting for demographic variables, no significant relationship was found between the polymorphism and progression of chronic Chagas' disease. Although our sample was limited, the results suggest that the progression of cardiomyopathy in chronic Chagas' disease is unrelated to the insertion/deletion polymorphism.

RAAS and adrenergic genes in heart failure: Function, predisposition and survival implications

It is well appreciated that several neurohormones and signaling cascades are activated that promote long-term deterioration of cardiac function and structure. Activation of the renin-angiotensin-aldosterone system (RAAS) and the adrenergic system is closely related to heart failure. Common gene variants that encode neurohormonal, adrenergic and intracellular proteins have been demonstrated to modulate the course and consequences of heart failure. However, the literature is replete with conflicting results and it remains uncertain as to whether particular gene variants predispose heart failure. Therefore, the main purpose of this review was to discuss the effects of single nucleotide polymorphisms (SNPs) that are located in genes encoding elements of the RAAS and the adrenergic system on the predisposition to and survival from heart failure. Most studies indicate that common SNPs encoding elements of the RAAS and the adrenergic system do not predispose individuals to heart failure. Conversely, it has been demonstrated that ARB1 Arg389Gly, GRK5 Gln41Leu, ACE I/D, CYP11B2 C-344T and AGTR1 A+1166C modulate pharmacological responses and have a considerable impact on cardiac-related survival. It should not be expected, however, that a single polymorphism determines survival, given that multiple gene products and environmental factors contribute to the pathogenesis of heart failure. Therefore, future studies should consider the interaction effects of multiple genes in populations that are as homogeneous as possible with respect to environmental characteristics.

Demonstrating the pharmacogenetic effects of angiotensin-converting enzyme inhibitors on long-term prognosis of diastolic heart failure

The objective of this study was to evaluate the effects of angiotensin-converting enzyme (ACE) inhibitors and pharmacogenetic interaction on the survival of the patients with diastolic heart failure (DHF). A total of 285 subjects with DHF confirmed by echocardiography were recruited in the period between 1995 and 2003. Baseline characteristics (age, sex, prior history, medication, and echocardiographic findings) and genetic polymorphisms (ACE gene insertion/deletion (I/D) polymorphism; T174M, M235T, G-6A, A-20C, G-152A, and G-217A polymorphisms of the angiotensinogen (AGT) gene; and A1166C polymorphisms of the angiotensin II type I receptor (AT1R)) were collected and matched (by propensity score) in those who received and those who did not receive ACE inhibitors. The patients were followed up to 10 years. Kaplan-Meier curves and Cox regression models were used to demonstrate the survival trend. The 85 patients who received ACE inhibitors and the other 85 patients who did not were found to have comparable baseline characteristics and polymorphism distribution. Prescription of ACE inhibitors was associated with a significant decrease in overall mortality (hazard ratio (HR), 0.45; 95% confidence interval (CI), 0.24-0.83; P=0.01), and a lower rate of cardiovascular events at 4000 days (HR, 0.53; 95% CI, 0.32-0.90; P=0.02). In addition, ACE I/D gene D allele was associated with higher overall mortality as compared with the I allele (HR, 2.04; P=0.003). This effect was diminished in those who received ACE inhibitors. The use of ACE inhibitor was associated with a significant decrease in long-term mortality and cardiovascular events in the patients with DHF. Genetic variants in the renin-angiotensin system genes were also associated, but their effects could be modified by the use of ACE inhibitors.

Renin-angiotensin system gene polymorphisms and diastolic heart failure

BACKGROUND

Diastolic heart failure (DHF) refers to an abnormality of diastolic distensibility, filling or relaxation of the left ventricle. The genetic study of DHF is scarce in the literature. The association of renin-angiotensin system (RAS) and DHF are well known. We hypothesized that RAS genes might be the susceptible genes for DHF and conducted a case-control study to prove the hypothesis.

MATERIALS AND METHODS

A total of 1452 consecutive patients were analysed and 148 patients with a diagnosis of DHF confirmed by echocardiography were recruited. We had two control populations. The first controls consisted of 286 normal subjects while the second were 148 matched controls selected on a 1-to-1 basis by age, sex, hypertension, diabetes and medication use. The angiotensin-converting enzyme (ACE) gene insertion/deletion polymorphism; multilocus polymorphisms of the angiotensinogen gene; and the A1166C polymorphisms of the angiotensin II type I receptor (AT(1)R) gene were genotyped.

RESULTS

In a single-locus analysis, the odds ratios (ORs) for DHF were significant with the ACE DD genotype and the AT(1)R 1166 CC plus AC genotype. In addition, the concomitant presence of ACE DD and AT(1)R 1166 CC/AC genotypes synergistically increased the predisposition to DHF.

CONCLUSIONS

Genetic variants in the RAS genes may determine an individual's risk to develop DHF. There is also a synergistic gene-gene interaction between the RAS genes in the development of DHF.

Ten renin-angiotensin system-related gene polymorphisms in maximally treated Canadian Caucasian patients with heart failure

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

The progression and pharmacological response of heart failure-affected patients are subject to interindividual variability. It is also acknowledged that the genotype frequency of certain gene polymorphisms varies across different ethnic groups and that a difference in gene polymorphism frequencies between healthy and heart failure patients seems to exist.

WHAT THIS STUDY ADDS

This study investigated associations between 10 gene polymorphisms of RAAS-related genes with an individual's susceptibility to heart failure. Our data suggest that the angiotensinogen (AGT) 235 single nucleotide polymorphism (SNP) may be associated with heart failure in our population and that the AGT(M174)-AGT(T235) haplotype, as well as the AGT/angiotensin-converting enzyme (ACE) gene combination, may play an important role in disease predisposition.

AIMS

Racial differences in survival outcomes point towards a genetic role in the pathophysiology of heart failure. Furthermore, contemporary evidence links genetics to heart failure (HF) predisposition. We tested for a difference in prevalence of 10 renin-angiotensin-aldosterone system (RAAS)-related gene polymorphisms between a homogenous population of HF patients and healthy controls.

METHODS

One hundred and eleven healthy volunteers and 58 HF patients were included in this study. The healthy control group consisted of males aged between 18 and 35 years old. The HF group consisted of patients (89.7% male) who were 63.8 +/- 7.9 years old, were in New York Heart Association (NYHA) class II-III and had a documented left ventricular ejection fraction (LVEF)

CONCLUSIONS

This study demonstrates that the SNPs of AGT may be associated with HF in our population and that the AGT/ACE gene combination may play an important role in disease predisposition.

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Key Words

• ace
• angiotensin
• heart failure
• polymorphisms
• raas
• renin

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MESH Headings

• Adolescent
• Adult
• Aged
• Canada/epidemiology
• Double-Blind Method
• Female
• Gene Frequency/genetics
• Genetic Predisposition to Disease/genetics
• Heart Failure/blood
• Heart Failure/genetics
• Humans
• Male
• Middle Aged
• Polymorphism, Genetic
• Renin-Angiotensin System/genetics
• White People/genetics

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Grants Collapse

Affiliation(s)

Marcin Zakrzewski-Jakubiak Université de MontréalMontréal, Canada
Simon de Denus Université de MontréalMontréal, Canada Montreal Heart InstituteMontréal, Canada
Marie-Pierre Dubé Montreal Heart InstituteMontréal, Canada
François Bélanger Université de MontréalMontréal, Canada
Michel White Montreal Heart InstituteMontréal, Canada
Jacques Turgeon Université de MontréalMontréal, Canada

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Genetic polymorphisms and heart failure

Heart failure is a complex clinical syndrome. There is evidence for a genetic contribution to the pathophysiology of heart failure. Considering the fundamental role of neurohormonal factors in the pathophysiology and progression of cardiac dysfunction and hypertrophy, variants of genes involved in this system are logical candidate genes in heart failure. In this report, genetic polymorphisms of the major neurohormonal systems in heart failure will be discussed. Studies on polymorphisms of the renin-angiotensin-aldosterone system (RAAS), adrenergic receptor polymorphisms, endothelin (receptor) polymorphisms, and a group of miscellaneous polymorphisms that may be involved in the development or phenotypic expression of heart failure will be reviewed. Research on left ventricular hypertrophy is also included. The majority of genetic association studies focused on the ACE I/D polymorphism. Initial genetic associations have often been difficult to replicate, mainly due to problems in study design and lack of power. Promising results have been obtained with genetic polymorphisms of the RAAS and sympathetic system. Considering the evidence so far, a modifying role for these polymorphisms seems more likely than a role of these variants as susceptibility genes. Besides the need for larger studies to examine the effects of single nucleotide polymorphisms and haplotypes, future studies also need to focus on the complexity of these systems and study gene-gene interactions and gene-environment interactions.

Prognostic effect of insertion/deletion polymorphism of the ace gene on renal and cardiovascular clinical outcomes in Chinese patients with type 2 diabetes

OBJECTIVE

The insertion/deletion (I/D) polymorphism of the ACE gene has been reported to be associated with diabetic microvascular or macrovascular complications. The aim of the present study was to investigate the prognostic effect of I/D polymorphism on renal and cardiovascular clinical outcomes in Chinese patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

A consecutive cohort of 1,281 Chinese patients with type 2 diabetes were followed for 41.3 +/- 21.6 months. Renal end points were defined as renal death and events (need for dialysis, plasma creatinine >/=500 micromol/l, or doubling of plasma creatinine of baseline value >/=150 micromol/l). Cardiovascular end points were defined as cardiovascular death and events, which included ischemic heart disease, heart failure, cerebrovascular accident, and revascularization requiring hospital admission. The I/D polymorphism of the ACE gene was examined by PCR followed by agarose gel electrophoresis.

RESULTS

The frequencies of ACE gene I/D polymorphisms were in Hardy-Weinberg equilibrium. Patients who developed a renal end point (n = 98) had higher frequencies of DD genotype (19.4 vs. 10.8%, P = 0.018) and D allele (41.3 vs. 31.8%, P = 0.006) compared with subjects who did not (n = 1,183). The cumulative rates of renal end points were 10.0, 19.2, and 24.4% in the II (n = 595), DI (n = 539), and DD genotype carriers (n = 147), respectively (log rank P = 0.004). In multiple Cox regression analysis, the occurrence of renal end points remained significantly influenced by I/D polymorphism with a dominant deleterious effect of the DD genotype (DD versus II, adjusted hazard ratio 2.80 [95% CI 1.49-5.29]). There was no prognostic effect of I/D polymorphism on cardiovascular end points.

CONCLUSIONS

The DD genotype of the ACE I/D polymorphism was an independent risk factor for renal but not cardiovascular end points in Chinese patients with type 2 diabetes.

Association of the angiotensin-converting enzyme gene polymorphism with chronic heart failure in Chinese Han patients

BACKGROUND

An insertion/deletion (I/D) polymorphism is present in the 16th intron of the angiotensin-converting enzyme (ACE) gene and is associated with serum and tissue ACE level. Some studies have shown that the DD genotype is associated with some cardiovascular diseases; while ACE polymorphism's effect on chronic heart failure (CHF) remains uncertain.

AIM

To investigate the association of the ACE gene I/D polymorphism with CHF in the Chinese Han population.

METHODS

The genotype was determined by polymerase chain reaction in 102 normal controls and in 79 patients with CHF. Plasma angiotensin (Ang) levels were assessed by radio-immunity assay. Left ventricular end-diastolic diameters (LVDD) and left ventricular ejection fractions were assessed by echocardiography.

RESULTS

The ACE gene polymorphism distribution was similar in patients and control subjects. However, ACE gene DD polymorphism was associated with a more severe condition, greater LVDD [mm: DD: 71+/-7, ID: 62+/-5, II: 60+/-5, P<0.001 DD vs. ID, P<0.001 DD vs. II] and higher plasma Ang II level [pg/ml DD: 92+/-19, ID: 79+/-21, II: 65+/-17 P<0.05 DD vs. ID, P<0.001 DD vs. II].

CONCLUSION

In Chinese Han patients with CHF, ACE gene DD polymorphism might be a marker of a more severe condition, and a higher level of activation of the renin-angiotensin system.

Association of two angiotensinogen gene polymorphisms, M235T and G(-6)A, with chronic heart failure

The aim of the study was to focus on the relationship between the angiotensinogen (AGT) gene polymorphisms, M235T and promoter G(-6)A, and chronic heart failure in the Czech population. A total of 158 patients with chronic heart failure (functional class NYHA II-IV, ejection fraction <40%, cardiothoracic index >50%) were compared with a control group of 200 subjects of similar age and sex distribution, without any personal history of cardiovascular diseases. The AGT gene polymorphisms were detected by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods. No significant differences in distributions of AGT genotypes between patients with chronic heart failure (CHF) and controls were found. The differences in distributions of alleles in AGT M235T (P(a)=0.02) and genotypes in AGT G(-6)A (P(g)=0.017) were found within women groups. Within CHF patients the distribution of AGT G(-6)A genotypes was not consistent with Hardy-Weinberg equilibrium (P=0.0001). We found significant relative risk of CHF in the GGMT genotype, OR=2.63 with 95% CI 1.39-4.95, P(corr)=0.01 (in the male group OR=1.83, 95% CI 0.92-3.66, P(corr)=0.3; in the female group OR=15.5, 95% CI 1.86-129.42, P(corr)=0.008). We provide evidence of increased risk in subjects with the GGMT variant of associated genotype of AGT gene for CHF, especially of fifteen-fold risk of this variant in women.

Polymorphisms in the RAS and cardiac function

Since the discovery of the polymorphism in the angiotensin converting enzyme (ACE) and the consequences of this polymorphism on the activity levels of the enzyme, numerous association studies have been performed. However, these investigations do not often adhere to the most stringent criteria for such studies. The initial study reporting a positive association of the ACE polymorphism and myocardial infarction showed an increased risk of the DD genotype. This initial association was eventually refuted by a large, well conducted association study, which found a risk ratio of 1.02 after combining their own data with all published data. Although such large, well conducted association studies have not been performed in left ventricular (LV) hypertrophy, the association between DD genotype and hypertrophy is more convincing with a 192% excess risk of LV hypertrophy in untreated hypertensives. The role of ACE genotype in LV growth is well established, especially in athletes. In heart failure, large studies or meta-analyses have not been performed, because most studies have selected different end-points. This hampers a proper meta-analysis of the results obtained in associations with heart failure. As most association studies do not fulfill the criteria for good association studies and use too small sample sizes, it remains important to perform a meta-analysis to add meaning to the results of such studies. Above all, it is important to obey the rules set for association studies, large sample size, small P values, report associations that make biological sense and alleles that affect the gene product in a physiologically meaningful way.