angiotensinogen and Hypertrophy--Left-Ventricular

Left ventricular hypertrophy (LVH) is an independent risk factor for morbidity and mortality from cardiovascular disease in men and women with hypertension and in asymptomatic subjects with normal blood pressure. In hypertensive patients it is a stronger coronary risk factor than casual blood pressure readings. Correlation between levels of high blood pressure, duration of hypertension and left ventricular mass is poor. Epidemiological studies suggest that left ventricular hypertrophy may be influenced by genetic factors. In our review we present study groups of genes contributing to the development of left ventricular hypertrophy: 1) genes that encode components of hormonal pathways, 2) genes of key sympathetic and parasympathetic receptors, 3) genes that modify intracellular ion homeostasis, 4) genes that modify energy metabolism, 5) genes that modify motor unit composition and regulation. Angiotensinogen gene, angiotensin-converting enzyme gene, angiotensin receptor type 1 gene, aldosterone synthase gene, nitric oxide synthase gene, type A natriuretic peptide receptor gene, beta(2)-adrenergic receptor gene, G-protein beta(3) subunit gene are associated with left ventricular hypertrophy.

Topics: Angiotensinogen; Female; Gene Expression; Genetic Markers; Humans; Hypertrophy, Left Ventricular; Male; Myocardium

Topics: Angiotensinogen; Antihypertensive Agents; Cytochrome P-450 CYP11B2; Genetic Markers; Humans; Hypertension; Hypertrophy, Left Ventricular; Peptidyl-Dipeptidase A; Polymorphism, Genetic; Receptor, Angiotensin, Type 1; Receptors, Angiotensin; Renin-Angiotensin System; Risk Factors

Topics: Aldosterone; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Animals; Hemodynamics; Humans; Hypertension; Hypertrophy, Left Ventricular; Risk Factors

On the basis of recent advances in molecular biology and statistical genetics, it has become possible to search for chromosome regions that contain genes predisposing to hypertension and to directly link specific mutations on candidate genes to hypertension. As the human genome has been extensively mapped, highly informative, polymorphic markers are available, which can be used to detect genes in their proximity with 'hypertensinogenic' alleles. Some of these markers have been shown to be tightly linked to the genes of the renin-angiotensin system. Furthermore, the coding and regulatory regions of the genes encoding for renin, ACE, angiotensinogen and the AT1 receptor have been partially characterized. This provides a basis for further definition of specific polymorphisms within these genes that are of functional importance and that can be used to examine their contribution to the inheritance of primary hypertension. The first studies of these links have already emerged and have been reviewed in this article. Several problems arise in performing such linkage studies in human primary hypertension, however. It is difficult to define the genetic background of heterogeneous, multigenetic and multifactorial diseases such as human hypertension. Extensive studies of population genetics, including the analysis of large numbers of generations and controlled breeding experiments, cannot be performed, for obvious reasons. Blood pressure is not a convenient study trait, because it exhibits great intraindividual variance and also because of the relatively low reliability of just a few indirect measurements obtained under loosely controlled environmental conditions. Twenty-four-hour ambulatory blood pressure measurements may improve such investigations in the near future. Ravogli et al (1990) reported that the 24-hour ambulatory systolic blood pressure is higher in normotensive subjects of hypertensive parents than in normotensive subjects of normotensive parents--a finding that had not been previously reported using the conventional method of measurement. Hypertension as a trait per se is also problematic: its classification (above 140/90 mmHg) is purely artefactual, and its aetiology is highly heterogeneous. Thus, we have to keep in mind that even strong gene effects, if present in only a small subgroup of hypertensives, may not be detected in these studies. Attempts are being made to strengthen the analysis by characterizing physiologically distinct subgroups. In ad

Topics: Angiotensin II; Angiotensinogen; Female; Humans; Hypertension; Hypertrophy, Left Ventricular; Myocardial Infarction; Peptidyl-Dipeptidase A; Pre-Eclampsia; Pregnancy; Receptors, Angiotensin; Renin; Renin-Angiotensin System

Several well controlled multicenter trials demonstrated the great value of ACE-inhibitors in the treatment of heart failure. Interestingly, the mechanisms by which ACE-inhibitors improve survival of patients with heart failure are ony poorly understood. Interesting new aspects regarding the role of the renin angiotensin system in the pathophysiology of heart failure emerged from modern methods of molecular biology. For example, several alleles of the angiotensin converting enzyme or angiotensinogen genes were related to hypertension and myocardial infarction in both clinical and experimental studies. Furthermore, local renin angiotensin systems have been demonstrated in various cardiovascular tissues. These tissue renin angiotensin systems are independently regulated and may be activated in heart failure or cardiac hypertrophy. Finally, it has been shown that inhibition of angiotensin converting enzyme affects also the metabolism of bradykinin and aldosterone which may contribute to the overall pharmacodynamic profile of ACE-inhibitors in heart failure.

Topics: Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Animals; Bradykinin; Gene Expression Regulation; Heart Failure; Hemodynamics; Humans; Hypertrophy, Left Ventricular; Peptidyl-Dipeptidase A; Renin-Angiotensin System

The allele threonine (T) of the angiotensinogen has been associated with ventricular hypertrophy in hypertensive patients and soccer players. However, the long-term effect of physical exercise in healthy athletes carrying the T allele remains unknown. We investigated the influence of methionine (M) or T allele of the angiotensinogen and D or I allele of the angiotensin-converting enzyme on left-ventricular mass index (LVMI) and maximal aerobic capacity in young healthy individuals after long-term physical exercise training.. Prospective clinical trial.. Eighty-three policemen aged between 20 and 35 years (mean+/-SD 26+/-4.5 years) were genotyped for the M235T gene angiotensinogen polymorphism (TT, n = 25; MM/MT, n = 58) and angiotensin-converting enzyme gene insertion/deletion (I/D) polymorphism (II, n = 18; DD/DI, n = 65). Left-ventricular morphology was evaluated by echocardiography and maximal aerobic capacity (VO2peak) by cardiopulmonary exercise test before and after 17 weeks of exercise training (50-80% VO2peak).. Baseline VO2peak and LVMI were similar between TT and MM/MT groups, and II and DD/DI groups. Exercise training increased significantly and similarly VO2peak in homozygous TT and MM/MT individuals, and homozygous II and DD/DI individuals. In addition, exercise training increased significantly LVMI in TT and MM/MT individuals (76.5+/-3 vs. 86.7+/-4, P = 0.00001 and 76.2+/-2 vs. 81.4+/-2, P = 0.00001, respectively), and II and DD/DI individuals (77.7+/-4 vs. 81.5+/-4, P = 0.0001 and 76+/-2 vs. 83.5+/-2, P = 0.0001, respectively). However, LVMI in TT individuals was significantly greater than in MM/MT individuals (P = 0.04). LVMI was not different between II and DD/DI individuals.. Left-ventricular hypertrophy caused by exercise training is exacerbated in homozygous TT individuals with angiotensinogen polymorphism.

Topics: Adult; Alleles; Analysis of Variance; Angiotensinogen; Brazil; Exercise Test; Exercise Therapy; Genotype; Humans; Hypertrophy, Left Ventricular; Male; Oxygen Consumption; Peptidyl-Dipeptidase A; Polymorphism, Genetic; Prospective Studies; Treatment Outcome

The renin-angiotensin-aldosterone system (RAAS) is important for the development of hypertension, and several antihypertensive drugs target this system. Our aim was to determine whether specific single nucleotide polymorphisms (SNPs) in RAAS genes were related to the blood pressure (BP) lowering effect of antihypertensive treatment.. Patients with mild to moderate primary hypertension and left ventricular hypertrophy were randomized in a double-blind fashion to treatment with either the angiotensin II type 1 receptor antagonist irbesartan (n = 48) or the beta(1)-adrenergic receptor blocker atenolol (n = 49) as monotherapy. A microarray-based minisequencing system was used to genotype 30 SNPs in seven genes in the RAAS. These polymorphisms were related to the antihypertensive response after 12 weeks treatment.. The BP reductions were similar in the atenolol and the irbesartan groups. Presence of the angiotensinogen (AGT) -6A allele or the AGT 235T allele were both associated with the most pronounced systolic BP response to atenolol treatment (P =.001 when -6 AA+AG was compared with GG and P =.008 for presence of the 235T variant compared with 235 MM).. We found that SNPs in the angiotensinogen gene were associated with the BP lowering response to atenolol. This study is limited by a relatively small sample size, and the results should therefore be viewed as preliminary. Despite this limitation, these results illustrate the potential of using SNP genotyping as a pharmacogenetic tool in antihypertensive treatment.

Topics: Angiotensin II Type 1 Receptor Blockers; Angiotensinogen; Antihypertensive Agents; Atenolol; Biphenyl Compounds; Blood Pressure; Double-Blind Method; Female; Genotype; Humans; Hypertension; Hypertrophy, Left Ventricular; Irbesartan; Male; Middle Aged; Polymorphism, Single Nucleotide; Renin-Angiotensin System; Tetrazoles; Treatment Outcome

Our aim was to determine whether the change in left ventricular (LV) mass in response to antihypertensive treatment could be predicted by multivariate analysis of single nucleotide polymorphisms (SNPs) in candidate genes reflecting pathways likely to be involved in blood pressure control.. Patients with mild to moderate primary hypertension and LV hypertrophy were randomized in a double-blind fashion to treatment with either the angiotensin II type 1 receptor antagonist irbesartan (n = 48) or the beta1 adrenoreceptor blocker atenolol (n = 49). A microarray-based minisequencing system was used for genotyping 74 SNPs in 25 genes. These genotypes were related to the change in LV mass index by echocardiography, after 12 weeks treatment as monotherapy, using stepwise multiple regression analysis.. The blood pressure reductions were similar and significant in both treatment groups. Two SNPs in two separate genes (the angiotensinogen T1198C polymorphism, corresponding to the M235T variant and the apolipoprotein B G10108A polymorphism) for those treated with irbesartan, and the adrenoreceptor alpha2A A1817G for those treated with atenolol, significantly predicted the change in LV mass. The predictive power of these SNPs was independent of the degree of blood pressure reduction.. SNPs in the angiotensinogen, apolipoprotein B, and the alpha2 adrenoreceptor gene predicted the change in LV mass during antihypertensive therapy. These results illustrate the potential of using microarray-based technology for SNP genotyping in predicting individual drug responses.

Topics: Adrenergic beta-Antagonists; Angiotensin II Type 1 Receptor Blockers; Angiotensinogen; Antihypertensive Agents; Apolipoproteins B; Atenolol; Biphenyl Compounds; Blood Pressure; Double-Blind Method; Echocardiography; Female; Genotype; Humans; Hypertension; Hypertrophy, Left Ventricular; Irbesartan; Male; Middle Aged; Multivariate Analysis; Oligonucleotide Array Sequence Analysis; Pharmacogenetics; Polymorphism, Single Nucleotide; Predictive Value of Tests; Receptors, Adrenergic, beta-2; Tetrazoles

Our aim was to determine if gene polymorphisms in the renin-angiotensin-aldosterone system (RAAS) were related to the degree of change in left ventricular hypertrophy (LVH) during antihypertensive treatment.. Patients with essential hypertension and echocardiographically diagnosed LVH were included in a double-blind study to receive treatment with either the angiotensin II type 1 receptor (AT1-receptor) antagonist irbesartan (n = 41), or the beta-1 adrenergic receptor blocker atenolol (n = 43) as monotherapy for 3 months. The angiotensinogen T174M and M235T, the angiotensin-converting enzyme I/D, the AT1-receptor A1166C and the aldosterone synthase (CYP11B2) -344 C/T polymorphisms were analysed and related to the change in left ventricular mass (LVM). Patients with the angiotensinogen 174 TM genotype treated with irbesartan responded with the greatest reduction in LVM (-23 +/- 31SD g/m2 for TM and +0.5 +/- 18 g/m2 for TT, P = 0.005), independent of blood pressure reduction. Both the angiotensinogen 235 T-allele (P = 0.02) and the AT1-receptor 1166 AC genotype responded with the greatest reduction in LVM when treated with irbesartan (-0.1 +/- 19 g/m2 for AA and -18 +/- 30 g/m2 for AC, P = 0.02), independent of blood pressure reduction. These polymorphisms were not associated with the change in LVM during treatment with atenolol.. The angiotensinogen T174M and M235T and the AT1-receptor A1166C polymorphisms were related to the change in LVH during antihypertensive treatment with an AT1-receptor antagonist; of these angiotensinogen T174M was the most powerful. This highlights the role of the RAAS for left ventricular hypertrophy and the potential of pharmacogenetics as a tool for guidance of antihypertensive therapy.

Topics: Aged; Alleles; Angiotensin Receptor Antagonists; Angiotensinogen; Antihypertensive Agents; Atenolol; Biphenyl Compounds; Female; Humans; Hypertension; Hypertrophy, Left Ventricular; Irbesartan; Male; Middle Aged; Polymorphism, Genetic; Receptor, Angiotensin, Type 1; Receptors, Angiotensin; Renin-Angiotensin System; Sweden; Tetrazoles

The angiotensinogen M235T polymorphism is positively associated with plasma angiotensinogen, hypertension, and coronary heart disease. However, the association of M235T polymorphism with left ventricular (LV) mass and function is not well defined at the population level. We investigated whether 2 tightly linked polymorphisms of angiotensinogen gene, M235T and G-6A, are associated with LV mass and function in a large population-based sample, composed mostly of patients with hypertension.. Two-dimensional guided M-mode and pulsed Doppler scan echocardiograms were performed in 605 participants. The angiotensinogen M235T was analyzed with a standard polymerase chain reaction test, and the G-6A variant was measured with mass spectrophotometry.. The association of angiotensinogen gene to LV mass and LV mass indexed to body surface area (LVMI) differed significantly between subjects with normotensive and hypertensive conditions with respect to the direction of association (P <.005). The methionine-threonine/threonine-threonine genotype was negatively associated with LV mass and LVMI in patients with hypertension after adjustment for blood pressure, antihypertensive medication use, weight, and other covariates (P <.001), and patients with normotensive conditions with the methionine-threonine/threonine-threonine genotype had higher LV mass and LVMI (P =.04, for LV mass; P =.14, for LVMI). The association in patients with normotensive conditions was not influenced by blood pressure but was partly confounded by weight.. Variation in the angiotensinogen gene was modestly associated with LV mass independently of covariates in patients with hypertensive conditions. The direction of the association was opposite to that observed in patients with normotensive conditions, probably because of the influence of other risk factors or antihypertensive medication use or both.

Topics: Analysis of Variance; Angiotensinogen; Cross-Sectional Studies; Female; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Middle Aged; Polymorphism, Genetic; Ventricular Dysfunction, Left

Activation of the local renin-angiotensin system (RAS) is an independent risk factor for the development of proteinuria and left ventricular hypertrophy (LVH) more commonly seen in masked hypertensives. It has been reported that urinary angiotensinogen (UAGT) level provides a specific index of the intrarenal RAS status. The aim of this study was to evaluate the association between UAGT and left ventricular mass index (LVMI) and urinary albumin-creatinine ratio (UACR) in renal transplant recipients (RTRs) with masked hypertension (HT). A total of 116 non-diabetic-treated hypertensive RTRs were included in this study. The patients were divided into two groups: masked hypertensives and controlled hypertensives. Forty-two (36.2%) of RTRs had masked HT. Mean UACR and LVMI levels were higher in RTRs with masked HT than in RTRs with controlled HT (P < 0.001). UAGT level was also higher in masked hypertensives compared to controlled hypertensives (P < 0.001). Multivariable regression analysis showed that UAGT was positively correlated with UACR (β = 0.024, P = 0.001) and LVMI (β = 0.082, P = 0.001) in masked hypertensives. Consequently, masked HT was considerably frequent (36.2%) in treated hypertensive RTRs and high UAGT levels accompanied by high albuminuria and LVMI levels were seen in these patients. Overproduction of the UAGT may play a pivotal role in the development of LVH and proteinuria in masked hypertensives.

Topics: Adult; Albuminuria; Angiotensinogen; Biomarkers; Blood Pressure; Female; Follow-Up Studies; Glomerular Filtration Rate; Graft Rejection; Graft Survival; Humans; Hypertrophy, Left Ventricular; Kidney Function Tests; Kidney Transplantation; Male; Masked Hypertension; Middle Aged; Postoperative Complications; Prognosis; Renin-Angiotensin System; Risk Factors; Transplant Recipients

The renin-angiotensin system (RAS) is thought to regulate blood pressure and to be an independent risk factor for the development of left ventricular hypertrophy (LVH) and carotid intima-media thickness (CIMT). Locally produced RAS in most tissues has been recently described. It has been reported that urinary angiotensinogen levels provide a specific index of the intrarenal RAS status and is significantly correlated with blood pressure and proteinuria. The aim of this study was to evaluate the relationship of local intrarenal RAS with LVH and CIMT in hypertensive renal transplant recipients (RTRs).. A total of 96 non-diabetic RTRs (50 hypertensive patients, 46 normotensive patients) were included in this study. Urinary angiotensinogen (UAGT)/urinary creatinine (Ucre) was significantly higher in hypertensive patients compared with normotensive patients (p < 0.01). Left ventricular mass (LVM)I and CIMT were significantly higher in hypertensive patients compared with the normotensive patients (p < 0.01). Importantly, a significant positive correlation was found between UAGT/Ucre levels and LVMI (r = 0.724, p = 0.012) and also CIMT (r = 0.452, p = 0.02) in hypertensive RTRs.. These data indicate that UAGT is increased in hypertensive RTRs, and local RAS may play an important role in the development of cardiovascular abnormalities in hypertensive renal transplant recipients.

Topics: Angiotensinogen; Blood Pressure Monitoring, Ambulatory; Carotid Intima-Media Thickness; Case-Control Studies; Creatinine; Female; Follow-Up Studies; Glomerular Filtration Rate; Graft Survival; Humans; Hypertension; Hypertrophy, Left Ventricular; Kidney Failure, Chronic; Kidney Function Tests; Kidney Transplantation; Male; Middle Aged; Postoperative Complications; Prognosis; Proteinuria; Renin-Angiotensin System; Risk Factors; Transplant Recipients

The angiotensinogen M235T and aldosterone synthase C-344T gene polymorphisms have been associated with cardiac and structure function. However, these associations in untreated hypertension remain unknown. We examined whether these variants determined both echocardiography indices and the potential associated underlying mechanisms, including cystatin-C and vascular inflammation.. The study population consisted of 319 untreated patients and 191 healthy individuals. Polymorphisms were determined by polymerase chain reaction technique. Left cardiac indices of geometry and function were assessed by echocardiography. Cystatin-C, intracellular cell adhesion molecule 1, and vascular cell adhesion molecule 1 levels were measured by enzyme-linked immunosorbent assay, whereas high sensitivity C-reactive protein levels were measured by immunonephelometry.. There was no significant interaction between the angiotensinogen genotypes on left ventricular mass index (LVMI) and diastolic function indices in all study groups. Regarding C-344T polymorphism, TT homozygous hypertensive subjects exhibited higher values of LVMI compared with C allele carriers (P = 0.02) and higher prevalence of concentric hypertrophy (P < 0.001). However, this polymorphism was not associated with variations in left atrial volume and diastolic dysfunction. Cystatin-C levels were correlated with LVMI values (r = 0.22; P = 0.002) and mean E/A ratio (r = -0.24; P < 0.001). Interestingly, a linear increase of LVMI with cyctatin-C quartiles has been revealed (F = 5.01; P < 0.001). Moreover, post hoc tests showed that increased levels of cystatin-C (above 75th percentile) were significantly different between both the first (P = 0.009) and the second quartile (P = 0.02).. We have shown that C-344T potentially predicts higher values of LVMI and concentric hypertrophy in untreated hypertension, independently of renal function and subclinical inflammation. Increased levels of cystatin-C were correlated with higher LVMI values.

Topics: Adult; Aged; Alleles; Angiotensinogen; Biomarkers; C-Reactive Protein; Case-Control Studies; Cystatin C; Cytochrome P-450 CYP11B2; Echocardiography; Female; Genetic Predisposition to Disease; Humans; Hypertension; Hypertrophy, Left Ventricular; Intercellular Adhesion Molecule-1; Male; Middle Aged; Prevalence; Vascular Cell Adhesion Molecule-1

Melusin is an integrin β1-interacting protein proposed to act as a biomechanical sensor in the heart. We characterized mechanisms and signalling pathways regulating cardiac melusin expression.. Infusion of arginine(8) -vasopressin (AVP) in Sprague-Dawley (SD) rats, spontaneously hypertensive rats (SHR) and double transgenic rats (dTGR) harbouring both human angiotensinogen and renin genes as well as infusion of angiotensin II (Ang II) in SD rats were used. The effect of direct left ventricular (LV) wall stretch was analysed by using isolated perfused rat heart preparation. For the cell culture studies, mouse atrial HL-1 cell line and neonatal rat ventricular myocytes (NRVMs) were used.. Left atrial melusin mRNA levels increased already after 30 min of AVP infusion. Ang II caused significant upregulation of left atrial melusin mRNA (2.1-fold at 6 h, P < 0.05) and protein (1.9-fold at 72 h, P < 0.05) levels. In contrast, LV melusin mRNA levels remained unchanged in response to both infusions, as well as to aortic banding-induced pressure overload. Direct LV wall stress or late-stage hypertensive heart disease did not modify LV melusin gene expression either. Interestingly, in atrial HL-1 cells, cyclic stretching increased melusin mRNA levels. Stretching and treatments with hypertrophic agonists increased melusin mRNA and protein levels in NRVMs, endothelin-1 being the most potent. PD98059, an extracellular signal-regulated protein kinase 1/2 inhibitor, markedly attenuated the endothelin-1-induced upregulation of melusin gene expression in NRVMs.. Multiple hypertrophic stimuli regulate melusin expression predominately in the atria, which may represent a necessary initial step in early adaptive remodelling processes.

Topics: Angiotensinogen; Animals; Animals, Newborn; Arginine Vasopressin; Cell Line; Cytoskeletal Proteins; Disease Models, Animal; Gene Expression Regulation; Heart Atria; Heart Ventricles; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Mice; Muscle Proteins; Myocytes, Cardiac; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Rats, Sprague-Dawley; Rats, Transgenic; Renin; RNA, Messenger; Signal Transduction; Time Factors

Identifying predictors of left ventricular hypertrophy has been an active study topic because of its association with cardiovascular morbidity and mortality. We examined the epistatic effect (gene-gene interaction) of two genes (angiotensin-converting enzyme (ACE) insertion/deletion (I/D); angiotensinogen (AGT) -6G-A, M235T, -20A-C) in the renin-angiotensin system on left ventricular mass (LVM) among hypertensive participants in the Hypertension Genetic Epidemiology Network study. Included were 2156 participants aged 20-87 years (60% women, 63% African American). We employed mixed linear regression models to assess main effects of four genetic variants on echocardigraphically determined LVM (indexed for height), and ACE-by-AGT epistatic effects. There was evidence that AGT -6G-A was associated with LVM among white participants: adjusted mean LVM (gm(-2.7)) increased with 'G' allele copy number ('AA':41.2, 'AG':42.3, 'GG':44.0; P=0.03). There was also evidence of an ACE I/D-by-AGT -20A-C epistatic effect among white participants (interaction P=0.03): among ACE 'DD' participants, AGT -20A-C 'C' allele carriers had lower mean LVM than 'AA' homozygotes ('DD/CC':39.2, 'DD/AC':39.9, 'DD/AA':43.9), with no similar significant effect among ACE 'I' allele carriers ('ID/CC':47.2, 'ID/AC':43.4, 'ID/AA':42.6; 'II/CC': NA, 'II/AC':41.3, 'II/AA':43.1). These findings indicate that renin-angiotensin system variants in at least two genes may interact to modulate LVM.

Topics: Adult; Aged; Aged, 80 and over; Angiotensinogen; Black or African American; Chi-Square Distribution; Epistasis, Genetic; Female; Gene Frequency; Genetic Predisposition to Disease; Genetic Variation; Homozygote; Humans; Hypertension; Hypertrophy, Left Ventricular; Linear Models; Male; Middle Aged; Peptidyl-Dipeptidase A; Phenotype; Risk Assessment; Risk Factors; United States; White People; Young Adult

Normal myocardium adapts to increase of nutritional fatty acid supply by upregulation of regulatory proteins of the fatty acid oxidation pathway. Because advanced heart failure is associated with reduction of regulatory proteins of fatty acid oxidation, we hypothesized that failing myocardium may not be able to adapt to increased fatty acid intake and therefore undergo lipid accumulation, potentially aggravating myocardial dysfunction. We determined the effect of high-fat diet in transgenic mice with overexpression of angiotensinogen in the myocardium (TG1306/R1). TG1306/R1 mice develop ANG II-mediated left ventricular hypertrophy, and at one year of age approximately half of the mice present heart failure associated with reduced expression of regulatory proteins of fatty acid oxidation and reduced palmitate oxidation during ex vivo working heart perfusion. Hypertrophied hearts from TG1306/R1 mice without heart failure adapted to high-fat feeding, similarly to hearts from wild-type mice, with upregulation of regulatory proteins of fatty acid oxidation and enhancement of palmitate oxidation. There was no myocardial lipid accumulation or contractile dysfunction. In contrast, hearts from TG1306/R1 mice presenting heart failure were unable to respond to high-fat feeding by upregulation of fatty acid oxidation proteins and enhancement of palmitate oxidation. This resulted in accumulation of triglycerides and ceramide in the myocardium, and aggravation of contractile dysfunction. In conclusion, hearts with ANG II-induced contractile failure have lost the ability to enhance fatty acid oxidation in response to increased fatty acid supply. The ensuing accumulation of lipid compounds may play a role in the observed aggravation of contractile dysfunction.

Topics: Angiotensin II; Angiotensinogen; Animals; Diet, High-Fat; Dietary Fats; Fatty Acids; Heart Failure; Hypertrophy, Left Ventricular; Lipid Metabolism; Male; Mice; Mice, Transgenic; Models, Animal; Myocardial Contraction; Myocardium; Oxidation-Reduction; Palmitates; Triglycerides; Ventricular Remodeling

Spontaneously hypertensive rats develop left ventricular hypertrophy, increased blood pressure and blood pressure variability, which are important determinants of heart damage, like the activation of renin-angiotensin system.. To investigate the effects of the time-course of hypertension over 1) hemodynamic and autonomic patterns (blood pressure; blood pressure variability; heart rate); 2) left ventricular hypertrophy; and 3) local and systemic Renin-angiotensin system of the spontaneously hypertensive rats.. MALE SPONTANEOUSLY HYPERTENSIVE RATS WERE RANDOMIZED INTO TWO GROUPS: young (n=13) and adult (n=12). Hemodynamic signals (blood pressure, heart rate), blood pressure variability (BPV) and spectral analysis of the autonomic components of blood pressure were analyzed. LEFT ventricular hypertrophy was measured by the ratio of LV mass to body weight (mg/g), by myocyte diameter (mum) and by relative fibrosis area (RFA, %). ACE and ACE2 activities were measured by fluorometry (UF/min), and plasma renin activity (PRA) was assessed by a radioimmunoassay (ng/mL/h). Cardiac gene expressions of Agt, Ace and Ace2 were quantified by RT-PCR (AU).. The time-course of hypertension in spontaneously hypertensive rats increased BPV and reduced the alpha index in adult spontaneously hypertensive rats. Adult rats showed increases in left ventricular hypertrophy and in RFA. Compared to young spontaneously hypertensive rats, adult spontaneously hypertensive rats had lower cardiac ACE and ACE2 activities, and high levels of PRA. No change was observed in gene expression of Renin-angiotensin system components.. The observed autonomic dysfunction and modulation of Renin-angiotensin system activity are contributing factors to end-organ damage in hypertension and could be interacting. Our findings suggest that the management of hypertensive disease must start before blood pressure reaches the highest stable levels and the consequent established end-organ damage is reached.

Topics: Age Factors; Angiotensin-Converting Enzyme 2; Angiotensinogen; Animals; Blood Pressure; Disease Models, Animal; Hemodynamics; Hypertension; Hypertrophy, Left Ventricular; Male; Peptidyl-Dipeptidase A; Random Allocation; Rats; Rats, Inbred SHR; Renin-Angiotensin System

Left ventricle hypertrophy (LVH) is main organ complication developing in the course of primary hypertension. Among 'candidates genes' related with development of hypertension as well as LVH; the promoting, but not crucial, influence of (c.704C>T) angiotensinogen (AGT) gene was found. The elevated calcium ions concentration in the cytosol of muscle cells, might be one of the element in the ethiopatomechanism of essential hypertension development. The ATP-related ions pomp--SERCA2A regulates the intracellular calcium concentration. Mutations in the ATP2A2 gene coding the SERCA2A protein, has been associated with elevated calcium level in cardiomyocytes. The aim of the study was to analyze frequency of the M235T (c.704C>T) AGT gene polymorphism. The new mutations in the ATP2A2 gene was searched for in hypertensive patients, independently to the LVH presence in compare to the control group. 157 people participated in the study. Based on the echo-cardiographic examination participants were divided into subgroups: patients with essential hypertension (NT) and patients with NT and LVH. 50 healthy volunteers served as the control group. The frequency of the CC homozygotes, of the M235T (c.704C>T) AGT gene polymorphism, was the highest in the patients with essential hypertension and LVH in compare with patients without LVH (p = 0.67) and control group (p = 0.64). The value of the LVMI was the highest in CC carriers in compare to homozygotes TT (p = 0.33) and CT group (p = 0.66). In homozygotes TT as well as in the carriers of allel T, the elevated blood pressures value was detected. In the exon 15 of ATPA2A gene the new polymorphism A724A (C.2171G>A) was found. only the presence of GG and heterozygotes GA was detected in analyzed group. The frequency of GA genotype was significantly higher in control group vs patients with essential hypertension with (p = 0.05)/or without LVH (p = 0.04). The GA carriers had lower blood pressures values measured in doctor office as well as using ABPM method. The LVM as well as LVMI values were lower in group with mutated genotype GA in compare to GG group (p = 0.107 for LVM; p = 0.154 for LVMI). Results suggest a protective role of the c.2171G>A polymorphism of the ATP2A2 gene against the hypertension as well as LVH development. It seems also that c.704C>T polymorphism of AGT gene does not play crucial role in the essential hypertension development.

Topics: Angiotensinogen; Female; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Middle Aged; Mutation; Polymorphism, Genetic; Sarcoplasmic Reticulum Calcium-Transporting ATPases

We evaluated the prevalences of ACE/ID, AGT/M235T, AT1R/A1166C, and CYP11B2/C344T genetic polymorphisms and their association with left ventricular hypertrophy (LVH) in Uzbek hypertensive men.. The study included 172 Uzbek men (mean age 47±10 years) with untreated essential hypertension (EH) of grade 1-2 and 60 normotensive subjects (mean age 41±10 years). All subjects underwent complete M-mode echocardiography to determine left ventricular mass (LVM) and LVM index (LVMI). Genomic DNA was extracted from peripheral blood and was analyzed using polymerase chain reaction-restriction fragment length polymorphism assays.. Left ventricular hypertrophy was detected in 148 hypertensive patients (86.1%). The frequencies of the D-allele of the ACE gene and T-allele of the CYP11B2 gene were higher among hypertensive patients than in the controls. There was a significant association between the AGT/M235T polymorphism and LVH. The 235T-allele of the AGT gene, the D-allele of the ACE gene, and the 344T-allele of the CYP11B2 gene were identified as "damaging" alleles. All the patients had "damaging" alleles, the number being one in only seven patients (4.1%), two in 52 patients (30.2%), and three in 89 patients (51.7%). The severity of LVH significantly increased with the number of "damaging" alleles. Among paired carriage of "damaging" alleles, the combination of the D+235T-alleles was found as the most unfavorable pair associated with the degree of LVH.. There is an association between EH and ACE/ID and CYP11B2/C344T gene polymorphisms in Uzbek males, with higher frequencies of the D-allele of the ACE gene and T-allele of the CYP11B2 gene. Our findings provide evidence for the association of AGT/M235T polymorphism with LVH in Uzbek males, combination of the D+235T-alleles being the most unfavorable pair associated with LVH.

Topics: Adult; Angiotensinogen; Case-Control Studies; Cytochrome P-450 CYP11B2; Echocardiography; Gene Frequency; Genotype; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Middle Aged; Peptidyl-Dipeptidase A; Polymorphism, Genetic; Prevalence; Receptor, Angiotensin, Type 1; Uzbekistan

We have recently reported that transgenic (mRen2)27 rats (Ren2 rats) exhibit pulmonary arterial hypertension (PAH), which is, in part, mediated by oxidative stress. Since 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors (statins) exhibit beneficial vascular effects independent of cholesterol synthesis, we hypothesized that rosuvastatin (RSV) treatment ameliorates PAH and pulmonary vascular remodeling in Ren2 rats, in part, by reducing oxidative stress. Six-week-old male Ren2 and Sprague-Dawley rats received RSV (10 mg x kg(-1) x day(-)1 ip) or vehicle for 3 wk. After treatment, right ventricular systolic pressure (RVSP) and mean arterial pressure (MAP) were measured. To evaluate treatment effects on pulmonary arteriole remodeling, morphometric analyses were performed to quantitate medial thickening and cell proliferation, whereas whole lung samples were used to quantitate the levels of 3-nitrotyrosine, superoxide, stable nitric oxide (NO) metabolites [nitrates and nitrites (NO(x))], and expression of NO synthase isoforms. In the Ren2 rat, RVSP is normal at 5 wk of age, PAH develops between 5 and 7 wk of age, and the elevated pressure is maintained with little variation through 13 wk. At 8 wk of age, left ventricular function and blood gases were normal in the Ren2 rat. Ren2 rats exhibited elevations in medial hypertrophy due to smooth muscle cell proliferation, 3-nitrotyrosine, NO(x), NADPH oxidase activity, and endothelial NO synthase expression compared with Sprague-Dawley rats. RSV significantly blunted the increase in RVSP but did not reduce MAP in the Ren2 rat; additionally, RSV significantly attenuated the elevated parameters examined in the Ren2 rat. These data suggest that statins may be a clinically viable adjunct treatment of PAH through reducing peroxynitrite formation.

Topics: Angiotensinogen; Animals; Fluorobenzenes; Heart Rate; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypertension, Pulmonary; Hypertrophy, Left Ventricular; Hypertrophy, Right Ventricular; Magnetic Resonance Imaging; Male; Membrane Glycoproteins; NADPH Oxidase 2; NADPH Oxidases; Nitric Oxide; Nitric Oxide Synthase Type III; Oxidative Stress; Peptidyl-Dipeptidase A; Pulmonary Artery; Pyrimidines; rac1 GTP-Binding Protein; Rats; Rats, Sprague-Dawley; Rats, Transgenic; Receptor, Angiotensin, Type 1; Rosuvastatin Calcium; Sulfonamides; Ventricular Function, Left; Ventricular Function, Right

We reported previously that targeted expression of rat prorenin to the liver under the control of the human alpha1-antitrypsin promoter increased plasma prorenin levels by several-hundred-fold in male transgenic rats and caused cardiac hypertrophy, severe renal lesions, and myocardial fibrosis by 20 weeks of age, despite normal blood pressure. We examined the evolution of the phenotype of male transgenic rats over 12 months and the effects of binephrectomy on the renin-angiotensin (Ang) system. Plasma prorenin levels were >1000-fold higher than in wild type littermates, whereas plasma and renal Ang II levels were no different from wild-type (WT) levels, and kidney renin levels were suppressed in transgenic rats. In contrast to our earlier report, transgenic rats had increased systolic blood pressure at 3 to 12 months of age, and only modest renal lesions and myocardial fibrosis were evident after 6 months of age. Binephrectomy reduced plasma renin activity and concentration and prorenin levels by 50% to 80% and Ang II levels by 90% in WT rats. By contrast, binephrectomy increased plasma renin activity and concentration and prorenin levels by 52.0-, 13.0-, and 5.8-fold, respectively, without change in Ang II levels in transgenic rats. We conclude that, in the animals studied in this report, elevated prorenin levels did not cause renal lesions or myocardial fibrosis during the first 6 months of age. Ang peptide formation consequent to the increased prorenin levels prevented reduction of Ang II levels after binephrectomy and was likely to have contributed to hypertension, cardiac hypertrophy, and suppression of kidney renin levels in these transgenic rats.

Topics: alpha 1-Antitrypsin; Angiotensin II; Angiotensinogen; Animals; Blood Pressure; Body Weight; Humans; Hypertension, Renal; Hypertrophy, Left Ventricular; Kidney; Liver; Male; Myocardium; Nephrectomy; Organ Size; Rats; Rats, Inbred F344; Rats, Transgenic; Renin; Transgenes

Controlling hypertension by angiotensin converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB), mechanisms that inhibit later pathway steps in the renin-angiotensin system (RAS), have clinically afforded protection against cardiac and renal disease.. In order to determine if blocking the RAS rate-limiting step of angiotensin II generation via renin inhibition could afford similar end organ protection in a human-relevant preclinical model, this study investigated the cardiac and renal effects of a nonpeptide, piperidine renin inhibitor (RI; 100 mg/kg/day PO) in double transgenic mice (dTGM) which express both human renin and angiotensinogen genes. RI was compared to the ARB, candesartan (3 mg/kg/day PO), and to the ACEI, enalapril (60 mg/kg/day PO) in a 4-week dosing paradigm. These doses of RI, ACEI and ARB were previously found to normalize mean blood pressure (MBP) to 110 + 3, 109 + 7 and 107 + 6 mmHg, respectively, after 1 day of treatment.. In the dTGM, PRA, plasma aldosterone, GFR, microalbuminuria and left ventricular free wall thickness (LVH) were higher than in the wild type C57BL/6 mice. Microalbuminuria and LVH were significantly reduced by 93% and 9% for the RI, 83% and 13% for enalapril and 73% and 6% for candesartan, respectively. PRA and aldosterone were reduced by the RI 56% and 23%, respectively. These results suggest that the RI provides protection against cardiac and renal disease, similar to ARB and ACEI.

Topics: Administration, Oral; Albuminuria; Aldosterone; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Animals; Benzimidazoles; Biphenyl Compounds; Blood Pressure; Cardiotonic Agents; Drug Administration Schedule; Enalapril; Female; Glomerular Filtration Rate; Humans; Hypertrophy, Left Ventricular; Kidney Diseases; Mice; Mice, Inbred C57BL; Mice, Transgenic; Molecular Structure; Piperidines; Quinolines; Renin; Renin-Angiotensin System; Tetrazoles; Time Factors; Ultrasonography

The activity of the renin-angiotensin system influences blood pressure (BP) and cardiovascular structure in humans. Therefore, we questioned whether left-ventricular (LV) structure and function are influenced by the -20 A/C variant of the angiotensinogen (AGT) gene in young normotensive or mildly hypertensive patients.. A homogenous cohort of young, male, white subjects (n = 214) with normal or mildly elevated BP never treated in the past, or on current cardiovascular medication, were recruited. All subjects were genotyped by single-strand conformational polymorphism analysis and DNA sequencing for the -20 A/C polymorphism of the AGT gene. Ambulatory BP was assessed over 24 h by an automatic portable device. Left-ventricular structure and function were determined by two-dimensional guided M-mode echocardiography.. The frequency of subjects homozygous for the -20 A allele was 73.4%, and the frequency for those with at least one copy of the -20 C allele was 26.6%. In hypertensive subjects with at least one copy of the -20 C allele, posterior (P = .027) and septal (P = .021) wall thickness, as well as LV mass (P = .027), were greater than in hypertensive subjects homozygous for the -20 A allele. Moreover, LV functional parameters such as midwall fractional fiber shortenings (P = .021) and the velocity of circumferential fiber shortening (P = .013) were decreased in hypertensive subjects with at least one copy of the -20 C allele, compared with subjects homozygous for the -20 A allele. Confounding factors of LV structure and systolic function, such as age, height, body mass index, physical activity, ambulatory 24-h BP, and sodium intake, were similar between the -20 A/C variants of the AGT gene in both normotensive and hypertensive subjects.. In young, mildly hypertensive subjects, cardiac structure and function are modulated by the -20 A/C gene variant of the AGT.

Topics: Adult; Angiotensinogen; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Polymorphism, Genetic; Ventricular Function, Left

Hypertension and left ventricular hypertrophy (LVH) are important causes of morbidity and mortality in the population. Angiotensinogen (AGT) M235T polymorphism has been associated with LVH, left ventricular dimensions, coronary artery disease and antihypertensive drug response in previous studies. We examined relationship between AGT M235T polymorphism and echocardiographic left ventricular indices in a Turkish population of treated hypertensive patients with normal coronary arteries.. In this cross-sectional study a Turkish population of 92 hypertensive patients treated in our outpatient clinic were enrolled. All patients had normal coronary angiographic examinations. Genotypes for AGT M235T were determined from peripheral leukocytes. Left ventricular dimensions, mass and function indices, after adjustment for clinical covariates were analyzed by multiple regression analysis according to genotypes.. Genotype frequencies for AGT M235T were MM-24.7%, MT-52.8% and TT-22.5%. Left ventricular end-systolic (LVES) dimensions for AGT M235T MM, MT, TT genotypes were 17.9+/-4.2 mm, 19.4+/-6.2 mm, and 16.4+/-2.9 mm, respectively (p=0.08). Angiotensinogen M235T TT genotype showed a trend towards a lower LVES dimension but results were not statistically significant. Left ventricular ejection fractions for AGT M235T MM, MT, TT subgroups were 61.3+/-15.0%, 59.4+/-14.0%, and 67.8+/-8.5%, respectively (p=0.07). Angiotensinogen M235T TT genotype showed a tendency towards lower left ventricular mass index but results were not statistically significant. None of the AGT M235T genotypes predicted left ventricular dilatation, mass or function in treated hypertensive patients with normal coronary arteries.. Angiotensinogen M235T polymorphism was not useful to predict left ventricular mass, function, hypertrophy or dilatation in a small population of treated Turkish hypertensive patients with normal coronary arteries.

Topics: Angiotensinogen; Coronary Vessels; Cross-Sectional Studies; Echocardiography; Female; Genotype; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Middle Aged; Polymorphism, Genetic; Predictive Value of Tests; Turkey; White People

Cross-sectional studies investigated the impact of renin-angiotensin system (RAS) gene polymorphism on left ventricular mass index (LVMI) with conflicting results. We conducted a longitudinal study to investigate the influence of the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) and angiotensinogen (AGT) M235T and angiotensin II type 1 receptor (AT1R) A1166C gene polymorphisms on the LVMI and geometry.. Of 1500 people screened, 110 nondiabetic normotensive elderly Chinese persons were recruited and received echocardiography at baseline and at the 2nd and 4th year follow-up. No participants had a history of organic heart disease or chronic medication. The gene polymorphisms were analyzed by using polymerase chain reaction.. Participant age was 71.9 +/- 3.9 years (range 60-81 years). The prevalence of concentric remodeling, eccentric hypertrophy, and concentric hypertrophy was significantly increased as well as LVMI after 4 years (all p <.05). These changes and the magnitude of LVMI increase were significantly higher in participants carrying the ACE D allele than non-D-allele carriers (all p <.05). This association was still significant in multivariate analyses (p

Topics: Aged; Aged, 80 and over; Aging; Angiotensinogen; Asian People; Cohort Studies; Female; Humans; Hypertrophy, Left Ventricular; Male; Middle Aged; Peptidyl-Dipeptidase A; Polymorphism, Genetic; Receptor, Angiotensin, Type 1; Taiwan; Ventricular Remodeling

Topics: Angiotensinogen; Antihypertensive Agents; Coronary Vessels; Female; Genetic Predisposition to Disease; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Polymorphism, Genetic; Turkey; White People

We have previously shown that a permanent deficiency in the brain renin-angiotensin system (RAS) may increase the sensitivity of the baroreflex control of heart rate. In this study we aimed at studying the involvement of the brain RAS in the cardiac reactivity to the beta-adrenoceptor (beta-AR) agonist isoproterenol (Iso). Transgenic rats with low brain angiotensinogen (TGR) were used. In isolated hearts, Iso induced a significantly greater increase in left ventricular (LV) pressure and maximal contraction (+dP/dt(max)) in the TGR than in the Sprague-Dawley (SD) rats. LV hypertrophy induced by Iso treatment was significantly higher in TGR than in SD rats (in g LV wt/100 g body wt, 0.28 +/- 0.004 vs. 0.24 +/- 0.004, respectively). The greater LV hypertrophy in TGR rats was associated with more pronounced downregulation of beta-AR and upregulation of LV beta-AR kinase-1 mRNA levels compared with those in SD rats. The decrease in the heart rate (HR) induced by the beta-AR antagonist metoprolol in conscious rats was significantly attenuated in TGR compared with SD rats (-9.9 +/- 1.7% vs. -18.1 +/- 1.5%), whereas the effect of parasympathetic blockade by atropine on HR was similar in both strains. These results indicate that TGR are more sensitive to beta-AR agonist-induced cardiac inotropic response and hypertrophy, possibly due to chronically low sympathetic outflow directed to the heart.

Topics: Adrenergic beta-Agonists; Adrenergic beta-Antagonists; Angiotensinogen; Animals; Animals, Genetically Modified; Brain; Cardiomegaly; Consciousness; Heart Rate; Hypertrophy, Left Ventricular; Isoproterenol; Male; Metoprolol; Myocardial Contraction; Rats; Rats, Sprague-Dawley; Ventricular Dysfunction, Left

The objective of this study was to evaluate the impact of variations of the angiotensinogen (AGT) and angiotensin II type I receptor (AGTR1) genes on progression of blood pressure (BP) and left ventricular mass (LVM) in multiethnic youth. The study was longitudinal involving 581 European American (EA) and African American (AA) youth with 12 assessments over a 15-year period. AGT M235T and three AGTR1 polymorphisms (C-521T, L191L and A1166C) were genotyped and individual growth curve modeling analyses were conducted. Single nucleotide polymorphism (SNP) analyses found a significant 3-way interaction between M235T, ethnicity and gender on BP levels. Systolic BP (SBP) levels were 5.8 mmHg (p = .00003) and diastolic BP (DBP) levels were 2.6 mmHg (p = .005) lower in carriers versus noncarriers of the M235 allele in AA males only. Furthermore, the AGTR1 L191 allele showed a SBP lowering effect in subjects with a high socioeconomic status (SES;p = .048) and a DBP lowering effect in AAs (p = .038). Haplotype analyses identified a protective haplotype (C-521, 191L and A1166) for LVM levels (p = .03). LVM in individuals homozygous for this haplotype was 12.9 g lower than those homozygous for the most common haplotype (-521T, 191L and A1166). No significant interactions were found between the AGT M235T polymorphism and any of the single SNPs or haplotypes of the AGTR1 gene. Our results in multiethnic youth uncover an ethnicity and gender-specific effect of the AGT M235T polymorphism and a SES or ethnicity-specific effect of the AGTR1 L191L polymorphism on the progression of hypertension risk. A protective AGTR1 haplotype for LVM was also identified.

Topics: Adolescent; Alleles; Angiotensinogen; Black People; Blood Pressure; Child; Female; Gene Frequency; Genotype; Haplotypes; Humans; Hypertension; Hypertrophy, Left Ventricular; Longitudinal Studies; Male; Models, Statistical; Polymorphism, Single Nucleotide; Receptor, Angiotensin, Type 1; Sex Factors; Social Class; Ventricular Function, Left; White People

In the European Project on Genes in Hypertension (EPOGH), we investigated in three populations to what extent in a family-based study, left ventricular mass (LVM) was associated with the C-532T and G-6A polymorphisms in the angiotensinogen (AGT) gene. We randomly recruited 221 nuclear families (384 parents and 440 offspring) in Cracow (Poland), Novosibirsk (Russia), and Mirano (Italy). Echocardiographic LVM was indexed to body surface area, adjusted for covariables, and subjected to multivariate analyses, using generalized estimating equations and quantitative transmission disequilibrium tests in a population-based and family-based approach, respectively. We found significant differences between the two Slavic centres and Mirano in left ventricular mass index (LVMI) (94.9 vs 80.4 g/m2), sodium excretion (229 vs 186 mmol/day), and the prevalence of the AGT -6A (55.7 vs 40.6%) and -532T (16.8 vs 9.4%) alleles. In population-based as well as in family-based analyses, we observed positive associations of LVMI and mean wall thickness (MWT) with the -532T allele in Slavic, but not in Italian male offspring. Furthermore, in Slavic male offspring, LVMI and MWT were significantly higher in carriers of the -532T/-6A haplotype than in those with the -532C/-6G or -532C/-6A allele combinations. In women, LVMI was neither associated with single AGT gene variants nor with the haplotypes (0.19 < P <0.98). In Slavic offspring carrying the AGT -532C/-6G or -532C/-6A haplotypes, LVMI significantly increased with higher sodium excretion (+3.5 g/m2/100 mmol; P=0.003), whereas such association was not present in -532T/-6A haplotype carriers (P-value for interaction 0.04). We found a positive association between LVMI and the AGT -532T allele due to increased MWT. This relation was observed in Slavic male offspring. It was therefore dependent on gender, age and ecogenetic context, and in addition it appeared to be modulated by the trophic effects of salt intake on LVM.

Topics: Adult; Age Factors; Angiotensinogen; Echocardiography; Female; Haplotypes; Heart Ventricles; Humans; Hypertrophy, Left Ventricular; Italy; Male; Medical History Taking; Middle Aged; Poland; Polymorphism, Genetic; Russia; Sex Factors; Sodium, Dietary

Angiotensinogen (AGT), the precursor of angiotensin II and a rate limiting factor in the renin-angiotensin system, is implicated in left ventricular hypertrophy, as angiotensin II is a potent stimulator of cardiac growth. A genetic variant (G-6A) in the proximal promoter region of the AGT gene may be particularly important for changes in left ventricular mass (LVM). However, previous findings associating this variant with LVM among relatively older adults with cardiovascular morbidity are inconsistent and contradictory.. This study examined the effect of G-6A polymorphism on LVM in a biethnic (African American and white), community-based sample of 362 asymptomatic younger adults (mean age 32.5 years, 71% white, 39% male). Two-dimensional M-mode echocardiography was used to assess LVM, and the indexation of LVM for height(2.7) (LVMI) was used to adjust for body size.. The frequency of the variant A(-6) allele was higher in subjects of African American than in white ethnicity (0.819 v 0.439, P < .0001), with carriers (GA+AA) representing 97.0% of African American as compared to 66.6% of white subjects. After adjusting for age, ethnicity (for total sample), gender, body mass index, systolic BP, and homeostasis model assessment index of insulin resistance, mean levels for both LVM and LVMI showed a significant decreasing trend with increasing gene dosage of the A(-6) allele in white subjects, African American subjects, and the total sample.. These results indicate that the A(-6) allele frequency differs markedly between African Americans and white individuals, and that the variant allele modulates LVM and LVMI in a beneficial manner in asymptomatic young adults of white and African American ethnicities.

Topics: Adult; Alleles; Angiotensinogen; Black or African American; Blood Pressure; Body Mass Index; Echocardiography; Female; Gene Frequency; Genotype; Heart Ventricles; Humans; Hypertrophy, Left Ventricular; Insulin Resistance; Male; Polymorphism, Single Nucleotide; Risk Factors; White People

We investigated the role of gene polymorphisms in angiotensin-converting enzyme (ACE), angiotensinogen, endothelial NO (eNO) synthase, and bradykinin receptor B2 in determining the cardiovascular system structure and function in hypertension and "athletic heart" syndrome. Using a PCR-based method, 114 hypertensive patients and 94 athletes were genotyped for I/D polymorphism of ACE, M235T angiotensinogen (ANG), Glu298 Asp endothelial synthase (eNOS), and type 2 receptor for bradykinin (BDKR2). Echocardiography and a 24 hour blood pressure monitoring being performed. The (+)-allel of BDKR2 gene was associated with the left ventricular hypertrophy and greater wall thickness in athletes and hypertensive subjects. The hypertensive patients, that were homozygous for Glu298 allele of eNOS, demonstrated a lower level of diastolic blood pressure than did those with Glu298 Asp and Asp298 Asp genotypes. At the same time, the ACE and AND gene polymorphisms displayed no association with the cardiac structure and function.

Topics: Adult; Alleles; Angiotensinogen; Blood Pressure; Female; Genetic Predisposition to Disease; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Middle Aged; Myocardium; Nitric Oxide Synthase; Peptidyl-Dipeptidase A; Polymorphism, Genetic; Polymorphism, Restriction Fragment Length; Receptor, Bradykinin B2; Sports Medicine

Endothelin-1 is involved in mechanical load-induced cardiac growth processes; it also has effects on contractility. The interaction of endothelin-1 and the Frank-Starling response is unknown. The present study aimed to characterize the role of endothelin-1 in the regulation of the Frank-Starling response, one of the major mechanisms regulating cardiac contractile force, in both normal and hypertrophied hearts. Nontransgenic rat hearts and hypertrophic hearts of hypertensive double transgenic rats harboring human angiotensinogen and renin genes were studied in a Langendorff isolated heart setup with a liquid-filled balloon inside the left ventricle used to measure contractile parameters. The rats were studied at compensated phase, before showing any signs of heart failure. Compensated hypertrophy in double transgenic rat hearts resulted in improved contractility at a given level of preload when compared with nontransgenic rat hearts. Hearts of both rat lines showed preserved Frank-Starling responses, that is, increased contractile function in response to increased end-diastolic pressure. The mixed endothelin A/B receptor antagonist bosentan attenuated the Frank-Starling response by 53% (P<0.01) in the double transgenic hearts but not in nontransgenic hearts. The diastolic parameters remained unaffected. The left ventricles of the double transgenic rat hearts showed an 82% higher level of endothelin type A receptor mRNA and a 25% higher level of immunoreactive endothelin-1 compared with nontransgenic rat hearts. The type 1 angiotensin II receptor antagonist CV-11974 had no significant effect on contractile function in response to load in either strain. These results show that endogenous endothelin-1 contributes to the Frank-Starling response in hypertrophied rat hearts by affecting systolic performance.

Topics: Angiotensin II; Angiotensin Receptor Antagonists; Angiotensinogen; Animals; Animals, Genetically Modified; Benzimidazoles; Biphenyl Compounds; Bosentan; Endothelin Receptor Antagonists; Endothelin-1; Heart Ventricles; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Myocardial Contraction; Organ Culture Techniques; Rats; Rats, Inbred SHR; Rats, Sprague-Dawley; Receptor, Angiotensin, Type 1; Renin; RNA, Messenger; Stress, Mechanical; Sulfonamides; Tetrazoles

Genetic polymorphisms of the angiotensinogen (AGT) and angiotensin-converting enzyme (ACE) genes are associated with increased risk of hypertension and left ventricular hypertrophy (LVH) in hypertensive subjects. However, the extent to which these polymorphisms are related to LVH and remodeling in dialysis patients remains unknown.. Two hundred and forty-six end-stage renal disease (ESRD) patients on peritoneal dialysis and 183 control subjects, all of Chinese origin, were genotyped for the ACE insertion/deletion (I/D) and the AGT M235T gene polymorphisms. Left ventricular mass index (LVMi) and relative wall thickness were measured using echocardiography.. Prevalence of ACE DD and AGT TT genotype was 14% and 83%, respectively, in ESRD patients and did not differ significantly from controls. A total percentage of 95% of our patients had LVH (171 with concentric and 63 with eccentric hypertrophy). Adjusting for age, gender, body mass index, duration of dialysis, diabetes, renal diagnosis, hematocrit, systolic and diastolic blood pressure, dialysis urea clearance, residual glomerular filtration rate, and use of converting enzyme inhibitors or angiotensin receptor blockers, AGT TT genotype remained independently associated with greater LVMi (coefficient = 28.73; 95% CI, 5.72 to 51.75; P = 0.015) and relative wall thickness (coefficient = 0.072; 95% CI, 0.022 to 0.122; P = 0.005) than MT/MM genotypes. LVMi and relative wall thickness did not differ significantly among patients with DD, DI, and II genotypes. No statistical significant interaction was noted between ACE and AGT gene polymorphism in relation to LVMi and relative wall thickness.. Polymorphism of the AGT M235T gene but not ACE I/D gene is associated with greater LVMi and relative wall thickness, indicating more concentric LVH, in Chinese peritoneal dialysis patients. Possible synergistic effects between AGT and ACE gene polymorphism require further evaluation in a larger population.

Topics: Adult; Angiotensinogen; Asian People; Echocardiography; Female; Genotype; Heart Ventricles; Humans; Hypertrophy, Left Ventricular; Kidney Failure, Chronic; Male; Middle Aged; Myocardium; Peptidyl-Dipeptidase A; Peritoneal Dialysis; Polymorphism, Genetic; Prevalence; Ventricular Remodeling

Left ventricular hypertrophy (LVH) is associated with an increased risk for cardiovascular morbidity and mortality. Epidemiological studies suggest that LVH may be influenced by genetic factors. However, the evidence associating individual genes with left ventricular (LV) mass is inconsistent and contradictory.. We investigated the association between angiotensin-converting enzyme insertion/deletion, angiotensinogen and alpha-adducin polymorphisms with LV mass and plasma renin activity (PRA) in 162 men with mild, never-treated hypertension who were recruited for the Hypertension and Ambulatory Recording Venetia Study. The effect of each polymorphism on LV mass and PRA was tested in one-way analysis of covariance using LV mass index or PRA as the dependent variable after adjusting for covariates.. The alpha-adducin polymorphism was the only individual polymorphism independently associated with LV mass index (F = 7.78, P= 0.006). Patients homozygous for the allele of that polymorphism had a LV mass index (123.4 +/- 10.5 g/m(2) ) significantly higher compared with heterozygotes (90.8 +/- 2.5 g/m(2) , P<0.01) or homozygotes (94.7 +/- 1.7 g/m(2) , P<0.05). These subjects also have significantly lower PRA (F = 4.2, P= 0.017). Albeit uncommon, 40% of homozygotes of the alpha-adducin polymorphism had LVH (odds ratio, 15.1; 95% confidence interval, 3.0-82.1).. The homozygotic state of the allele of alpha-adducin polymorphism is independently associated with increased LV mass and low PRA. These data suggest that genetic considerations may contribute importantly to risk stratification, and perhaps therapeutic interventions targeted at LVH and the renin-angiotensin system in hypertensive patients.

Topics: Adult; Alleles; Angiotensinogen; Calmodulin-Binding Proteins; Echocardiography; Homozygote; Humans; Hypertrophy, Left Ventricular; Male; Middle Aged; Peptidyl-Dipeptidase A; Polymorphism, Genetic; Renin

Left ventricular hypertrophy in patients with hypertension is a main clinical prognostic entity The aim of this study was to evaluate the association between mutations at genes of the renin-angiotensin system (RAS) and the development of left ventricular hypertrophy. Genetic polymorphism in angiotensinogen (AGT) and angiotensin Il-type 1 receptor (AT1R) genes was examined in a group of well-selected essential hypertensive caucasians with left ventricular involvement (n = 40) and a group of healthy unrelated caucasians (n = 150). Cardiac morphology and function were assessed by M-mode echocardiography. Molecular variants were analysed by amplified fragment length polymorphism. We observed a statistically significant difference both for AGT and AT1R genotype distribution in patients with left ventricular hypertrophy compared with controls (p<0.05). A 0.49 and 0.225 frequency was detected among cases for T and C mutant alleles at AGT and AT1R genes. Mutations in RAS genes are involved in the pathophysiology of target-organ damage in essential hypertension. Evaluation of molecular factors conferring a risk of developing heart involvement may lead to better identification of patient subgroups and more effective control of the clinical course.

Topics: Adult; Aged; Alleles; Angiotensinogen; Female; Heart Function Tests; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Middle Aged; Mutation; Polymorphism, Genetic; Receptor, Angiotensin, Type 1; Receptors, Angiotensin; Renin-Angiotensin System

Angiotensinogen (AGT), one of the major components in the renin-angiotensin system, has been linked to hypertension in humans and animals. We have previously systemically administered antisense oligonucleotides and plasmid vectors with DNA that targeted AGT and attenuated hypertension in spontaneously hypertensive rats. The aim of the present study was to prolong the effect of antisense treatment by the use of a recombinant adeno-associated viral (rAAV) vector targeted to AGT. Using a model of lifelong hypertension in which 5-day-old spontaneously hypertensive rats are treated, a single intracardiac injection of rAAV-AGT-antisense (rAAV-AGT-AS) delayed the onset of hypertension for 91 days and significantly attenuated hypertension in adulthood for up to 6 months. Systolic blood pressure was always lower, by up to 23 mm Hg in the AS-treated group. The vector was stable and expressed a reporter gene in liver, kidney, and heart. The rAAV-AGT-AS treatment significantly decreased left ventricular hypertrophy (P=0.01) and also lowered levels of AGT in the liver (2.78+/-0.61 microgram/g tissue versus 5.23+/-0.41 microgram/g tissue for the sense-treated group, P<0.01). Measurement of liver transaminases showed no evidence for liver toxicity. We conclude that rAAV-AGT-AS offers a safe, stable approach for gene therapy of hypertension.

Topics: Adenoviridae; Age Factors; Angiotensinogen; Animals; Blood Pressure; Genes, Reporter; Genetic Therapy; Genetic Vectors; Hypertension; Hypertrophy, Left Ventricular; Kidney; Liver; Myocardium; Oligonucleotides, Antisense; Rats; Rats, Inbred SHR; Time Factors; Transaminases

In view of their mutual crosstalk, the roles of angiotensin II (Ang II) and endothelin-1 (ET-1) in the myocardium are assumed to be synergistic and supplemental.. In the phase of compensated left ventricular (LV) hypertrophy of Dahl salt-sensitive rats, Ang II peptide and the ACE mRNA in the LV were increased by 1.6- and 3.8-fold, respectively. In contrast, ET-1 peptide and the preproET-1 mRNA remained unchanged. In subsequent congestive heart failure (CHF), Ang II and ACE mRNA did not show further increases. But ET-1 and the mRNA were increased de novo by 5.3- and 4.1-fold, respectively. In ascending aorta-banded rats, the local activations of Ang II and ET-1 also showed a differential time course between LV hypertrophy and CHF. Long-term treatments of Dahl salt-sensitive rats with temocapril (an ACE inhibitor) and with bosentan (a mixed ET receptor blocker) equally improved long-term survival. Temocapril reduced the LV/body weight ratio and ameliorated LV fractional shortening. Conversely, although bosentan equally improved fractional shortening, it did not reduce the increase in LV mass. Combined treatment with these 2 drugs further ameliorated the animal's survival without additional decreases in systolic pressure.. The pathophysiological roles in the myocardium during the transition to CHF differ qualitatively between Ang II and ET-1. Thus, long-term therapy with a combination of ACE inhibition and ET antagonism may provide a new approach for heart failure in humans.

Topics: Angiotensin II; Angiotensinogen; Animals; Antihypertensive Agents; Blood Pressure; Bosentan; Disease Progression; Endothelin-1; Endothelins; Gene Expression Regulation; Heart Failure; Heart Ventricles; Hemodynamics; Hypertrophy, Left Ventricular; Male; Organ Size; Peptidyl-Dipeptidase A; Protein Precursors; Rats; Rats, Inbred Dahl; Rats, Sprague-Dawley; RNA, Messenger; Sulfonamides; Survival Analysis; Thiazepines; Time Factors

We investigated cardiac function in rats transgenic for the human renin and angiotensinogen genes (TGR) to test the hypothesis that elevated local angiotensin II precipitates adrenergic dysfunction and abnormal contractile function.. Hearts from TGR and Sprague-Dawley control rats, aged 6 weeks, were studied using the Langendorff model and papillary muscle preparations (n = 6-10 per group). Incremental isoproterenol (1 - 1000 nmol/l) and external Ca2+-concentrations (0.75-6.0 mmol/l) were tested. Cardiac protein and mRNA expression levels were determined by Western blot and RNAase protection assay.. TGR rats showed left ventricular hypertrophy (54%), higher blood pressures (76 mmHg), and elevated plasma renin activity (seven-fold) compared to controls (P < 0.01). The effect of isoproterenol on TGR rat systolic and diastolic left ventricular performance was decreased in both in-vitro models compared to controls (two- to threefold, P < 0.01). TGR rat papillary muscles showed impaired force generation with abnormal basal and Ca2+-dependent relaxation. Gialpha2 and Gialpha3 protein levels were increased (20-30%) and SERCA2a and adenylyl cyclase protein levels were decreased (23 and 37%, respectively) in TGR hearts compared to controls, while Gsalpha or beta1 and beta2-receptor levels were unchanged. Cardiac angiotensin converting enzyme and atrial natriuretic peptide mRNA levels were increased more than four-fold in TGR with no differences for the angiotensin type1 receptor, beta1-receptor, SERCA2a, phospholamban, adenylyl cyclase V and angiotensinogen genes.. TGR rat hearts develop severe adrenergic dysfunction with decreased adenylyl cyclase and abnormal intracellular Ca2+-homeostasis. Our findings emphasize angiotensin II as a major risk factor promoting early functional decline in cardiac hypertrophy. The data may have implications for patients with activating polymorphisms of the renin-angiotensin system and support the need for an early therapeutic intervention.

Topics: Adrenergic beta-Agonists; Angiotensinogen; Animals; Animals, Genetically Modified; Blood Pressure; Calcium; Coronary Circulation; Humans; Hypertension; Hypertrophy, Left Ventricular; In Vitro Techniques; Isoproterenol; Male; Myocardial Contraction; Myocardium; Papillary Muscles; Rats; Rats, Sprague-Dawley; Receptors, Adrenergic; Reference Values; Renin; Ventricular Function, Left

The aim of the present study was to determine if there is an association of different gene polymorphisms of renin-angiotensin system and left ventricular hypertrophy (LVH) in patients with essential hypertension (EH) in St Petersburg population.. We examined 156 patients (the mean age 49+/-8 years) with mild-to-moderate EH recruited from the general population of the outpatient clinic. Left ventricular mass was measured by echocardiography and left ventricular mass index (LVMI) was calculated. Subjects were genotyped for I/D polymorphism of the angiotensin-converting enzyme (ACE) gene, A1166C polymorphism of the AT1 receptor gene, M235T polymorphism of angiotensinogen gene and -6G/A polymorphism of its promoter region.. Genotype distribution of the sample obeyed Hardy-Weinberg equilibrium and was comparable to that reported previously for hypertensive individuals. Groups of patients with II, ID and DD polymorphism of ACE gene did not differ significantly in their LVMI levels. Furthermore, neither ID ACE-gene polymorphism nor ATI-receptor gene and angiotensinogen gene polymorphism was associated with LVH. Additionally, no any significant gene-gene interactions were found to be associated with LVH in the group studied.. In the light of these observations it seems reasonable to make a preliminary conclusion about lack of association between LVH and distinct polymorphisms of renin-angiotensin system genes in the population studied.

Topics: Adult; Angiotensinogen; Chi-Square Distribution; Electrocardiography; Female; Genetic Testing; Genotype; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Middle Aged; Peptidyl-Dipeptidase A; Polymorphism, Single Nucleotide; Receptor, Angiotensin, Type 1; Receptors, Angiotensin; Renin-Angiotensin System; Russia

Genetic factors may be important in modifying heart size due to long-term athletic training. The significance of polymorphisms of genes of the renin-angiotensin system in myocardial mass in a population of athletes participating in different disciplines is not known.. The angiotensin I-converting enzyme gene insertion/deletion (I/D) polymorphism, angiotensinogen gene M235T polymorphism and angiotensin II type 1 receptor gene A1166C polymorphism were determined in 83 male Caucasian endurance athletes and associated with left ventricular mass.. No association with left ventricular mass was found for the polymorphisms of angiotensin I-converting enzyme gene I/D, angiotensinogen gene M235T and angiotensin II type 1 gene A1166C when studied separately. However, combined analysis of the angiotensin I-converting enzyme gene I/D polymorphism and angiotensinogen gene M235T polymorphism genotypes suggested an association with left ventricular mass (g m(-2)) (P = 0.023). Athletes with the angiotensin I-converting enzyme gene DD/angiotensinogen gene TT genotype combination had greater left ventricular mass compared with all other genotype combinations (179.8 +/- 26.1 g m(-2) vs. 145.2 +/- 27.3 g m(-2), P = 0.003).. These results suggest an association of combined angiotensin I-converting enzyme gene I/D polymorphism genotypes, and angiotensinogen gene M235T polymorphism genotypes with left ventricular hypertrophy due to long-term athletic training. A synergistic effect of angiotensin I-converting enzyme gene DD genotype and angiotensinogen gene TT genotype on left ventricular mass in endurance athletes appears to occur.

Topics: Adolescent; Adult; Angiotensinogen; Echocardiography; Genotype; Heart; Heart Ventricles; Humans; Hypertrophy, Left Ventricular; Male; Peptidyl-Dipeptidase A; Physical Endurance; Polymorphism, Genetic; Receptor, Angiotensin, Type 1; Receptors, Angiotensin; Renin-Angiotensin System; Sports

Left ventricular hypertrophy (LVH) entails numerous functional and molecular changes that ultimately lead to cardiac insufficiency. The renin-angiotensin system and adrenergic receptor signalling pathway have both been implicated in LVH progression and interactions between these factors may precipitate contractile dysfunction. We therefore investigated cardiac function in hypertensive rats transgenic for the human renin and angiotensinogen genes (TGR) having a genetic activation of the renin-angiotensin system, stroke-prone spontaneously hypertensive rats (SHR) and normotensive controls (CTR) aged 6 weeks. The isolated perfused heart model was used and the effect of isoproterenol (0.1-1000 nmol/L on cardiac function was studied. Cardiac protein and gene expression was studied by Western blot and RNase protection assay. TGR had 75 mmHg higher blood pressure and a 24% higher cardiac/body weight ratio than CTR; blood pressure in SHR was 17 mmHg higher without heart weight difference (p < 0.05). Basal Pmax, +dP/dt and -dP/dt were higher in TGR and SHR compared with CTR hearts. Isoproterenol stimulated these parameters by a maximum factor 6-8 in CTR and SHR but had almost no effect in TGR (p < 0.05). Basal CF per g heart weight was similar in all experimental groups. Isoproterenol produced a significantly smaller vasodilation in TGR compared with CTR or SHR. beta 1 and beta 2 receptor and Gs alpha proteins were similar in TGR, SHR and CTR. Gi alpha was increased in TGR hearts (p < 0.05). Converting enzyme and atrial natriuretic factor mRNA expression was increased (p < 0.01) while beta 1 receptor, adenylyl-cyclase V, SERCA2a and phospholamban mRNA expression was unchanged in TGR compared with CTR. Thus, LVH in TGR is characterised by early adrenergic dysfunction and beta 1 receptor signalling abnormalities indicating progressive functional deterioration. The data may serve as support for an early preventive intervention in angiotensin-II dependent cardiac hypertrophy and may have also implications for patients with genetic alterations of the renin-angiotensin system.

Topics: Adrenergic beta-Agonists; Angiotensinogen; Animals; Animals, Genetically Modified; Atrial Natriuretic Factor; Blood Pressure; Blotting, Western; Body Weight; Cardiotonic Agents; Gene Expression Regulation; GTP-Binding Protein alpha Subunits, Gi-Go; GTP-Binding Protein alpha Subunits, Gs; Heart; Humans; Hypertension; Hypertrophy, Left Ventricular; Isoproterenol; Male; Myocardial Contraction; Organ Size; Peptidyl-Dipeptidase A; Rats; Rats, Inbred SHR; Rats, Sprague-Dawley; Receptors, Adrenergic, beta; Renin; Renin-Angiotensin System; Serine Proteinase Inhibitors; Vasodilator Agents

A missense gene mutation with methione-to-threonine amino acid substitution at codon 235 (M235T) of angiotensinogen (AGT) has been associated with higher plasma AGT levels and may influence the pathogenesis of cardiac hypertrophy and atherosclerosis. This study was undertaken to investigate the relationship of the M235T polymorphism of the AGT gene with left ventricular mass (LVM) and carotid intima-media thickness (IMT) in 175 Chinese patients with hypertension. The M235T mutation was detected by a mispairing primer method to create a BstUI restriction site in the polymerase chain reaction. The LVM was calculated with M-mode echocardiographic measures of the left ventricle. The IMT was measured in the common carotid and carotid bifurcation by B-mode ultrasound. Patients with the TT genotype (n = 106) were found to have significantly greater LVM index than those with the MM (n = 32) and MT (n = 37) genotypes (129.2 +/- 34.3 v 112.5 +/- 38.3 and 107.4 +/- 30.0 g/m2, P = .002), but the carotid IMT showed insignificant differences among three genotypic groups (1.320 +/- 0.703, 1.349 +/- 0.777, and 1.309 +/- 0.797 mm, P = .97). The M235T polymorphism (P = .004) was a significant predictor for LVM on multiple regression analysis, controlling all the potential confounding factors including age (P = .04), gender (P = .000), body mass index (P = .000), and so on, but the carotid IMT correlated only with age (P = .000), smoking (P = .02), and tissue plasminogen activator antigen (P = .02). These results indicated that the TT genotype of the AGT gene could be considered a risk factor for the development of cardiac hypertrophy, but not for carotid atherosclerosis in the hypertensive population.

Topics: Amino Acid Substitution; Angiotensinogen; Arteriosclerosis; Blood Flow Velocity; Blood Pressure; Carotid Arteries; Carotid Artery Diseases; DNA; DNA Primers; Echocardiography, Doppler, Pulsed; Female; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Middle Aged; Mutation, Missense; Polymerase Chain Reaction; Polymorphism, Genetic; Predictive Value of Tests; Ultrasonography, Doppler, Duplex

We studied whether left ventricular mass in athletes associates with polymorphisms in genes encoding components of the renin-angiotensin system.. Adaptive left ventricular hypertrophy is a feature of the athlete's heart. However, similarly training athletes develop left ventricular mass to a different extent, suggesting that genetic factors may modulate heart size.. We measured left ventricular mass by echocardiography in 50 male and 30 female elite endurance athletes aged 25 +/- 4 (mean +/- SD) years. Deoxyribonucleic acid samples were prepared for genotyping of angiotensinogen (AGT) gene M235T polymorphism, angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and angiotensin II type 1 receptor (AT1) gene A1166C polymorphism.. The AGT gene M235T genotypes were significantly associated with left ventricular mass independently of blood pressure in both genders (p = 0.0036 for pooled data). TT homozygotes had greater mass compared with MM homozygotes in both men (147 +/- 12 g/m vs. 132 +/- 15 g/m, p = 0.032) and women (121 +/- 12 g/m vs. 101 +/- 13 g/m, p = 0.019). There was a gender difference in the relation between myocardial mass and AGT genotype, MT heterozygotes resembling MM homozygotes among women and TT homozygotes among men. The other studied gene polymorphisms were not associated with left ventricular mass.. Angiotensinogen gene M235T polymorphism is associated with the variability in left ventricular hypertrophy induced by endurance training, with athletes homozygous for the T allele having the largest hearts. We found no association between ACE gene I/D or AT1 gene A1166C polymorphisms and left ventricular mass.

Topics: Adaptation, Physiological; Adult; Angiotensinogen; Echocardiography; Female; Genetic Predisposition to Disease; Genotype; Heterozygote; Homozygote; Humans; Hypertrophy, Left Ventricular; Male; Peptidyl-Dipeptidase A; Physical Endurance; Polymorphism, Genetic; Receptors, Angiotensin; Sex Factors; Sports

The intrarenal factors responsible for hypertension in double-transgenic rats (dTGR) harboring human renin and human angiotensinogen genes are unclear. The pressure-natriuresis and -diuresis relationships in response to chronic angiotensin-converting enzyme (ACE) inhibition and AT1 receptor blockade were evaluated. Renal renin-angiotensin and nitric oxide (NO) system gene expression was also investigated. Six-week-old dTGR were treated for 3 wk with submaximal doses of cilazapril (10 mg/kg, orally) or losartan (10 mg/kg, orally) or with the drug combination. In untreated dTGR, pressure-natriuresis relationships were maximally shifted rightward by approximately 70 to 80 mmHg, and both renal blood flow (RBF) and GFR were markedly decreased. Submaximal cilazapril and losartan dosages both decreased systolic BP by 30 mmHg and shifted the pressure-natriuresis curves leftward by 25 to 30 mmHg. Cilazapril increased RBF and GFR to values observed in normotensive control animals but did not significantly affect fractional sodium excretion (FENa) or fractional water excretion (FEH2O) curves. In contrast, losartan had no significant effect on RBF or GFR but shifted the FENa and FEH2O curves leftward. The cilazapril and losartan combination completely normalized BP and shifted the pressure-natriuresis curves leftward more than did either drug alone. When cilazapril and losartan were administered at higher doses (30 mg/kg, orally), the two drugs equally shifted the pressure-natriuresis curves leftward, by 50 mmHg. Both drugs increased RBF and GFR; however, only losartan shifted FENa and FEH2O curves leftward. Human and rat renin and angiotensinogen genes were downregulated in dTGR and were increased by losartan and cilazapril treatments, whereas no changes in the expression of rat ACE and AT1A receptor genes were observed. Endothelial NO synthase expression was increased by cilazapril but not by losartan. Neither inducible NO synthase nor neural NO synthase gene expression was affected by drug treatments. Therefore, submaximal ACE inhibition enhanced sodium excretion mainly by increasing RBF and GFR, whereas submaximal AT1 receptor blockade decreased tubular sodium and water reabsorption. The combination of the two drugs produced an additive effect. The ACE inhibitor effects may involve increased endothelial NO synthase expression, perhaps related to the inhibition of bradykinin degradation.

Topics: Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Animals; Animals, Genetically Modified; Antihypertensive Agents; Blood Pressure; Cilazapril; Diuresis; Humans; Hypertrophy, Left Ventricular; In Situ Hybridization; Kidney; Losartan; Male; Natriuresis; Nucleic Acid Hybridization; Rats; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Renin; Ribonucleases

The groups of patients with myocardial infarction (MI) and hypertrophy of the left ventricle (HLV) (n = 45 and n = 53, respectively) and a sample of healthy individuals from the Moscow population (n = 60) were examined for T174M polymorphism of AGT gene (replacement of methionine for threonine at position 174 of the correspondent amino acid sequence). In MI patients the content of TT genotypes and T allele was significantly lower than in the control group (57.8% against 80% and 67.9 against 89.2%, respectively), whereas the proportion of M allele and TM heterozygotes was increased (32.1 against 10.8% and 37.8 against 18.3%, respectively). In patients with HLV, the proportion of TT genotype (64.2%) and T allele (77.4%) was also lower than in the control group, whereas the frequency of M allele was increased (22.6%). Our results suggest that the T174M polymorphism of AGT gene is associated with MI and HLV in the Moscow population.

Topics: Adult; Angiotensinogen; Case-Control Studies; Female; Genetic Predisposition to Disease; Genotype; Humans; Hypertrophy, Left Ventricular; Male; Middle Aged; Moscow; Myocardial Infarction; Polymorphism, Genetic

The molecular variants M235T and T174M of the angiotensinogen gene have been linked to essential hypertension in some populations, but there are discrepancies about this association in other studies. We studied 75 patients with essential hypertension (BP > 160/100 mm Hg) from our outpatient clinic, aged 55+/-1 years, 30 men, systolic BP 182+/-2.5, diastolic BP 109+/-1 mm Hg (mean +/- SEM), and a family history of the disease. Target organ damage was evaluated by measuring urinary albumin excretion rate, left ventricular hypertrophy, and fundoscopy. As a control group, 75 healthy subjects with BP < 130/85 mm Hg and with no family history of cardiovascular disease were selected. M235T and T174M angiotensinogen genotypes were determined by PCR and subsequent digestion of the products with SfaNI and NcoI, respectively. The frequency (q) of genotypes of the variant M235T in the patients with essential hypertension was MM 0.31, MT 0.41, and TT 0.28, not significantly different (P = .93) from that of the controls (MM 0.28, MT 0.44, and TT 0.28). For the variant T174M, the genotype frequencies in hypertensives were TT 0.83, TM 0.15, and MM 0.02, which was not significantly different (P = .89) from that of the controls (TT 0.86, TM 0.12, and MM 0.02). Similarly, there was no evidence for association between angiotensinogen genotypes and hypertension in subjects aged < or = 40 years old (n = 24) or with severe (stage III) hypertension (n = 31). Within the group of patients with essential hypertension, there were no differences in genotype distribution between patients with and without retinopathy (n = 31), left ventricular hypertrophy (n = 37), or microalbuminuria (n = 14). This study shows that M235T and T174M variants are not associated either with essential hypertension or with target organ damage in a Spanish sample.

Topics: Adult; Aged; Albuminuria; Alleles; Angiotensinogen; Echocardiography; Female; Gene Frequency; Genotype; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Middle Aged; Polymorphism, Genetic

Variants of renin-angiotensin system genes are shown to be associated with cardiovascular pathology. The association between renin-angiotensin system genes and left ventricular mass was investigated in a population-based case-control study.. The association between echocardiographic left ventricular mass and both insertion/deletion polymorphism of the angiotensin-converting enzyme gene and the methionine-threonine variant at position 235 of the angiotensinogen gene was studied in a random cohort of 430 hypertensive and 426 control subjects. No differences in the adjusted left ventricular mass values between the different genotypes were seen among either the hypertensive or the control subjects, whether men or women, or in the subgroups of normotensive or physically active subjects. Gene variation had no statistically significant synergistic effect on left ventricular mass values. In control women, the deletion allele of the angiotensin-converting enzyme gene was associated with an increased risk of left ventricular hypertrophy. However, this finding was based on a small number of women with left ventricular hypertrophy and should be interpreted with caution.. Variations in renin-angiotensin system genes had no major effect on left ventricular mass in this middle-aged population-based cohort of hypertensives and control subjects.

Topics: Adult; Alleles; Angiotensinogen; Cardiac Volume; Case-Control Studies; Chromosome Deletion; Cohort Studies; Echocardiography; Female; Genetic Variation; Genotype; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Middle Aged; Peptidyl-Dipeptidase A; Polymorphism, Genetic; Renin-Angiotensin System; Risk Factors

Both myocardial and plasma endothelin-1 (ET-1) are elevated in congestive heart failure (CHF). However, the role played by endogenous ET-1 in the progression of CHF remains unknown. The aim of the present study was to investigate and correlate myocardial gene expression programs and left ventricular (LV) remodeling during chronic ET-receptor antagonism in CHF rats. After ligation of the left coronary artery, rats were randomized to oral treatment with a nonselective ET-receptor antagonist (bosentan, 100 mg . kg-1 . day-1, n = 11) or vehicle (saline, n = 13) for 15 days, starting 24 h after induction of myocardial infarction. Bosentan substantially attenuated LV dilatation during postinfarction failure as evaluated by echocardiography. Furthermore, bosentan decreased LV systolic and end-diastolic pressures and increased fractional shortening. Myocardial expression of preproET-1 mRNA and a fetal gene program characteristic of myocardial hypertrophy were increased in the CHF rats and were not affected by bosentan. Consistently, right ventricular-to-body weight ratios, diameters of cardiomyocytes, and echocardiographic analysis demonstrated a sustained hypertrophic response and a normalized relative wall thickness after intervention with bosentan. Thus the modest reduction of preload and afterload provided by bosentan substantially attenuates LV dilatation, causing improved pressure-volume relationships. However, the compensatory hypertrophic response was not altered by ET-receptor antagonism. Therefore, ET-1 does not appear to play a crucial role in the mechanisms of myocardial hypertrophy during the early phase of postinfarction failure.

Topics: Angiotensinogen; Animals; Bosentan; Coronary Vessels; Endothelin Receptor Antagonists; Gene Expression; Heart Failure; Hypertrophy, Left Ventricular; Ligation; Male; Myocardial Infarction; Myocardium; Rats; Rats, Wistar; Receptor, Endothelin A; Receptors, Endothelin; RNA, Messenger; Sulfonamides; Ventricular Function, Left

The phenotypic expression of left ventricular hypertrophy (LVH) in patients with hypertrophic cardiomyopathy (HCM) is variable. This phenotypic variability is not completely explained by the responsible mutations or other known factors. Recent data denote a role for the modifier genes and environmental factors. We studied the role of 3 potential modifier genes, i.e., angiotensinogen (AGT), angiotensin II receptor 1a (AT1a), and endothelin-1 (END1) on the phenotypic expression of LVH in patients with hypertrophic cardiomyopathy (HCM).. The study population was comprised of 108 genetically independent patients with HCM. Left ventricular mass index (LVMI) and LVH score were determined per published protocols. The genotypes of AGT (M235T, T174M, and G-6A), AT1a, and END1 were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) or mutation-specific PCR (MS-PCR).. Male patients had higher mean LVMI and LVH score than female patients (146.0 +/- 33.5 vs 129.4 +/- 33.6, p = 0.01 and 6.0 vs 5.0, p = 0.010, respectively). Gender accounted for 4.8% and 5.4% of the variability of LVMI and LVH score, respectively. The END1 genotypes also had a significant influence on LVH scores accounting for 2.9% of their variability (p = 0.042). The median LVH score was greater in patients with the AA and AG genotypes, as compared to patients with the GG genotype (7.0 vs 5.0, p = 0.034). Neither the AGT nor the AT1 genotypes had a significant influence on the expression of LVH. In multivariate regression analysis, END1 and gender accounted for 7.3% of the variability of the LVH score (p = 0.007).. Our results show that gender and the END1 gene modify the phenotypic expression of hypertrophy in patients with HCM.

Topics: Adult; Angiotensinogen; Cardiomyopathy, Hypertrophic; DNA Primers; Endothelin-1; Female; Gene Expression; Genotype; Humans; Hypertrophy, Left Ventricular; Male; Middle Aged; Phenotype; Polymerase Chain Reaction; Polymorphism, Genetic; Receptors, Angiotensin; Sex Characteristics

The purpose of the present study was to assess whether the insertion (I)/deletion (D) polymorphism of the angiotensin converting enzyme (ACE) gene, and the polymorphism of angiotensinogen (AGT) gene with threonine (T) instead of methionine (M) at amino acid 235 in exon 2 (M235T) were associated with left ventricular dilatation after myocardial infarction. In 103 patients with myocardial infarction, the left ventricular (LV) end-diastolic volume index (EDVI) and the end-systolic volume index (ESVI) were assessed by echocardiography at two time points, namely at 7 +/- 4 days and at 3.9 +/- 1.3 months (mean +/- S.D.) after the infarction. The increases in the LVEDVI and LVESVI on the second echocardiogram were significantly higher in subjects with the DD and ID genotypes than in patients with the II genotype (P < 0.05 and P < 0.005, respectively). Multiple regression analysis revealed that the LVESVI at the first echocardiographic examination and the ACE I/D genotype were significant predictors of the LVEDVI and LVESVI at the second echocardiographic examination. However, the AGT M235T genotype was eliminated. In conclusion, the DD and ID genotypes of the ACE gene were significantly associated with the progression of the LVEDVI and LVESVI after myocardial infarction. The presence of the deletion allele of the ACE gene may be a risk factor of congestive heart failure after a myocardial infarction.

Topics: Analysis of Variance; Angiotensinogen; Echocardiography; Female; Genotype; Heart Failure; Humans; Hypertrophy, Left Ventricular; Male; Middle Aged; Myocardial Infarction; Peptidyl-Dipeptidase A; Regression Analysis; Ventricular Dysfunction, Left

To study the effect of captopril treatment and its withdrawal on the circulating and tissue peptidyl-dipeptidase A, angiotensinogen (AGT), and angiotensin II (A II), in relation to left ventricular hypertrophy (LVH) and systolic blood pressure (SBP).. SHR male rats were given captopril 100 mg.kg-1.d-1 [SHRcap, number (n) = 43] orally in mixture with milk powder as vehicle from intrautero period of 16 wk of age. Rats were killed at 16 (n = 19) and 40 (n = 24) wk of age, respectively. Male, age-matched untreated SHR and WKY rats served as controls. SBP, left ventricular mass/body weight (LVM/BW) ratio, left ventricular (LV) myocardium and plasma A II concentration, aortic and serum peptidyl-dipeptidase A activity, AGT mRNA level in kidney and liver, renal renin mRNA level were determined.. Captopril treatment decreased SBP and reduced LVM/BW at 16 and 40 wk of age, and persistently inhibited LV myocardium A II, aortic peptidyl-dipeptidase A activity, and AGT gene expression in kidney even after the treatment was removed. Nevertheless, no changes were found in plasma A II concentration, serum peptidyl-dipeptidase A activity, and AGT mRNA level in liver by captopril therapy. Renal renin mRNA level was low in SHR and WKY rats, but it was increased by captopril treatment. Tissue renin-angiotensin system (RAS) such as AGT mRNA in kidney, aortic peptidyl-dipeptidase A activity, and LV myocardium A II, rather than circulating RAS (AGT mRNA in liver, renin mRNA in kidney, serum peptidyl-dipeptidase A activity and plasma A II), were persistently inhibited by early captopril treatment, even after the withdrawal of the treatment.. The long-term inhibition of tissue RAS is one of the mechanisms of the persistent hypotensive effect of captopril treatment.

Topics: Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Animals; Captopril; Hypertension; Hypertrophy, Left Ventricular; Male; Peptidyl-Dipeptidase A; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Renin-Angiotensin System; RNA, Messenger

Experimental myocardial infarction is a model of cardiac overload in which part of the cardiac muscle is removed. The resulting left ventricle insufficiency depends on the size of the infarct and time. The infarcted area remodels, due to proteolytic activity of inflammatory cells and collagenogenesis from fibroblast activity. The phenotype of the residual healthy cardiac muscle undergoes modification, and there are peripheral vascular changes which are partly dependent on the activation of pressor systems and/or inactivation of dilator systems. The changes are proportional to the infarct size at any given time after induction of the model. The degree of right ventricular hypertrophy and the drop in arterial pressure are upstream and downstream markers of the loss of left ventricular function and therefore indicate the extent of the remodelling. The increase of type V3isomyosin, the amount of subendocardial collagen, and the biosynthesis, storage and secretion of atrial natriuretic factor (ANF) are all proportional to the infarct size and the degree of cardiac overload. The level of urinary cGMP is also correlated with infarct size. These indices show ventricular remodelling, increased stress and energy restriction of the residual healthy cardiac muscle. The activation of peripheral pressor systems also depends on infarct size. They reflect the influence of defective cardiac pumping on the kidney, liver, brain and endothelium. Massive infarcts are accompanied by an increase in circulating renin and in renal renin content, by a decrease in angiotensinogen due to its consumption by renin, and to its insufficient hepatic synthesis, and by an increase in vasopressin secretion and biosynthesis in the hypothalamus. Converting enzyme inhibition has beneficial effect in this model by lowering cardiac load. It reduces arterial pressure, reverses bi-atrial and right ventricular hypertrophy, reduces the changes in the myosin isoenzyme patterns, and normalizes subendocardial fibrosis and the level of ANF. Although the effects of converting enzyme inhibition are beneficial in this model, they are restricted by their inability to normalize the load and stress when the initial loss of cardiac contractile material exceeds 40%.

Topics: Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Animals; Atrial Natriuretic Factor; Collagen; Cyclic GMP; Hypertrophy, Left Ventricular; Indoles; Isoenzymes; Kidney; Myocardial Infarction; Myocardium; Myosins; Perindopril; Rats; Rats, Wistar; Renin; Vasopressins; Ventricular Dysfunction, Left