Role of angiotensin II type I (AT1 A1166C) receptor polymorphism in susceptibility of left ventricular dysfunction

Influence of angiotensin II type 1 receptors and angiotensin-converting enzyme I/D gene polymorphisms on the progression of Chagas' heart disease in a Brazilian cohort: Impact of therapy on clinical outcomes

Chagas disease (CD), a neglected tropical disease, is caused by infection by the protozoan Trypanosoma cruzi. One-third of CD patients develop cardiac disease (CARD), an inflammatory and fibrotic process that may progress to heart failure associated with reduced left ventricular ejection fraction (LVEF). The determinants of CD progression are still uncertain. In non-infectious conditions, the angiotensin-converting enzyme (ACE) functional insertion (I)/deletion (D) and type 1 angiotensin II receptor (AT1R) +1166A>C gene polymorphisms have been linked to clinical outcomes. In a Brazilian cohort of 402 patients with positive serology for CD, in a case-control study we used PCR for genotyping the ACE rs4646994 I/D and AGTR1 rs5182C>T, rs275653 -119C>T, rs2131127A>G and rs5186 +1166A>C polymorphisms to evaluate association with CARD and progression to heart failure. Patients were classified as non-CARD (stage A; 109), and mild (stage B1; 161) or severe (stage C; 132) CARD. The groups were compared using unconditional logistic regression analysis and adjusted for non-genetic covariates (age, gender, and trypanocidal treatment). ACE II genotype appeared less frequent in C patients (15% in C vs 20% in B1 and 27% in A). After covariate adjustments, the ACE D allele showed a borderline association with susceptibility to severe CARD (C vs A: OR = 1.9; P = 0.08). AGTR1 +1166AC genotype showed a borderline association with protection against the progression and severity of CARD (C vs A: OR = 0.6; P = 0.09; C vs B1: OR = 0.6; P = 0.07; C vs A + B1: OR = 0.6; P = 0.05). However, adjustments for multiple comparisons showed no association of ACE I/D and AGTR1 polymorphisms with susceptibility and severity of CARD. The rs275653/rs2131127/rs5186/rs5182 T/A/C/T haplotype was protective against progression to the severe form of CARD (C vs B1: OR = 0.3; P = 0.03). Moreover, patients with ACE II and AGTR1 rs5186 +1166AC genotypes presented higher LVEF%. In C patients, TNF serum levels were higher in ACE D carriers than in II genotype. Although limited in number, a cross-sectional observation suggests that C-stage patients treated with benznidazole years prior to administration of ACE inhibitors/AT1R antagonists show reduced TNF serum levels and improved LVEF%. Therefore, variants of ACE and AGTR1 genes may influence the outcome of Chagas' heart disease and should be explored in precision medicine. Further, pharmacotherapies may improve immunological abnormality and clinical outcome in CD patients. Altogether, these data support prospective studies of this cohort and replication in other cohorts.

Association between polymorphisms of genes involved in the Renin-Angiotensin-Aldosterone System and the adaptive morphological and functional responses to essential hypertension

Hypertensive cardiac remodeling is illustrated by increased left ventricular (LV) mass index values and/or relative wall thickness (RWT) values >0.42, and functionally by isolated alteration of LV diastole (abnormal relaxation). The aim of the present study was to establish differentiated models of anatomical and functional adaptation to essential hypertension (EHT), in relation to the genetic variants of genes involved in the Renin-Angiotensin-Aldosterone System (RAAS). The M235T-AGT, I/D-ACE, A1166C-R1AngII, A3123C-R2AngII and G83A-REN genotypes were determined using PCR-Restriction Fragment Length Polymorphism in 139 hypertensive subjects. The relationship between the studied RAAS gene polymorphisms with morphological and functional cardiac remodeling was assessed by multiple logistic regression analysis. Patients carrying the C/C, A/C genotypes (A3123C-R2AngII polymorphism) had a 2.72-fold (P=0.033) increased risk of exhibiting an RWT value <0.42; in the multivariate model the risk was 4.02-fold higher (P=0.008). Analysis of LV diastolic dysfunction (LVDD) revealed that hypertensive patients carrying the T/T, M/T genotypes (M235T-AGT polymorphism) had a 2.24-fold (P=0.037) increased risk of developing LVDD and a 2.42-fold increased risk (P=0.039) after adjustment for confounders. Similarly, carriers of the G/G, A/G genotypes (G83A-REN) had a 2.32-fold (P=0.021) increased risk of developing LVDD, and this remained an independent risk factor based on the multivariate model (P=0.033). The results of the present study showed that no particular gene was associated with increased LV mass, but the A3123C-R2AngII polymorphism was associated with a non-concentric type of cardiac response in hypertensive patients. Conversely, the M235T-AGT and G83A-REN polymorphisms were found to be statistically significantly associated with LVDD when assessing abnormal relaxation.

Leptin, Galectin-3 and Angiotensin II Type 1 Receptor Polymorphism in Overweight and Obese Patients with Heart Failure - Role and Functional Interplay

Background and Aims

Leptin, one of the best-known adipocytes, together with the renin-angiotensin-aldosterone system and galectin-3 are important players in inflammation, arterial hypertension and heart failure pathophysiology. Moreover, uninucleotide A1166C polymorphism is associated with hypertension and poor prognosis in heart failure. The aim of the study was to investigate a possible relationship between leptin serum values, specific heart failure biomarkers and the presence of AT1 receptor A1166C polymorphism in overweight and obese heart failure patients.

Methods

The study included 88 consecutive overweight and obese patients admitted for decompensated heart failure. NT-proBNP, MR-proANP, galectin-3 and leptin levels were determined on the arrival day. Genotyping of the A1166C allele – AT1 receptor gene was performed in all patients in order to find variants.

Results

We found a strong positive correlation (r = 0.347, p = 0.001) between leptin serum concentrations and BMI. Leptin levels were not correlated with heart failure biomarkers (NT-proBNP, MR-proANP and galectin-3). All homozygote CC variants were hypertensive, but we registered no significant difference in genetic AC and AA variants distribution between hypertensive and normotensive. Leptin was not significantly modified by the presence of potentially pathogenic A1166C–AT 1 receptor genotypes (AC + CC). But, galectin-3 was found in higher concentrations in patients with heterozygous and homozygous A1166C mutations.

Conclusion

Overweight and obese patients with heart failure display high leptin serum levels. Leptin does not offer incremental prognostic value in heart failure overweight and obese patients. But, galectin-3 was found in higher concentrations in patients with heterozygous and homozygous A1166C mutations, suggesting a worse prognosis probably due to more advanced cardiac fibrosis.

Sarcomeric Gene Variants and Their Role with Left Ventricular Dysfunction in Background of Coronary Artery Disease

: Cardiovascular diseases are one of the leading causes of death in developing countries, generally originating as coronary artery disease (CAD) or hypertension. In later stages, many CAD patients develop left ventricle dysfunction (LVD). Left ventricular ejection fraction (LVEF) is the most prevalent prognostic factor in CAD patients. LVD is a complex multifactorial condition in which the left ventricle of the heart becomes functionally impaired. Various genetic studies have correlated LVD with dilated cardiomyopathy (DCM). In recent years, enormous progress has been made in identifying the genetic causes of cardiac diseases, which has further led to a greater understanding of molecular mechanisms underlying each disease. This progress has increased the probability of establishing a specific genetic diagnosis, and thus providing new opportunities for practitioners, patients, and families to utilize this genetic information. A large number of mutations in sarcomeric genes have been discovered in cardiomyopathies. In this review, we will explore the role of the sarcomeric genes in LVD in CAD patients, which is a major cause of cardiac failure and results in heart failure.

LINKS BETWEEN RENIN-ANGIOTENSIN SYSTEM GENETIC POLYMORPHISMS AND LEPTIN SECRETION IN OBESE HEART FAILURE PATIENTS

Chronic heart failure (CHF) and obesity are two conditions frequently associated and which, despite all the advances made in their management in the recent years, their prevalence continues to rise. Obese patients present unique challenges in the diagnosis of CHF and also therapeutic particularities. The genetic differences may be a possible explanation for the fact that some people, irrespective of their lifestyle and common classical cardiovascular risk factors, are more susceptible to develop heart failure. Moreover, the adipose tissue, a huge endocrine organ which secretes adipokines, is also a well-established source of all renin-angiotensin-aldosterone system components, being strongly involved in the pathogenesis of CHF. That is why this review will explore the possible links between the RAS genetic polymorphisms and leptin secretion in obese HF patients, trying to bring a more precise understanding of this relationship, which will undoubtedly facilitate a more appropriate treatment of HF in obese patients. We also try to explain the possible incriminated mechanisms, and plausible biological explanations for the relationship between RAS genetic polymorphisms and adipokines secretion in obese heart failure patients.