natriuretic-peptide--brain and Cardiomegaly

The underlying mechanism for clinical and biochemical manifestations of chronic heart failure (HF) may be due in part to neurohumoral adaptations, such as activation of the renin-angiotensin-aldosterone and sympathetic nervous systems in the periphery and the brain. Internet search and discussion with colleagues are the methods for this study. Since chronic HF is associated with autonomic imbalance with increased sympathetic nerve activity and a withdrawal of parasympathetic activity, it may be considered a brain disease. This phenomenon may be the result of an increased systemic and cerebral angiotensin II signaling because plasma angiotensin II is increased in humans and animals with chronic HF. The increase in angiotensin II signaling enhances sympathetic nerve activity through actions on both central and peripheral sites during chronic HF. Activation of angiotensin II signaling in different brain sites such as the paraventricular nucleus (PVN), rostral ventrolateral medulla (RVLM), and area postrema (AP) may increase the release of norepinephrine, oxidative stress, and inflammation leading to increased cardiac contractility. It is possible that blocking angiotensin II type 1 receptors decreases sympathetic nerve activity and cardiac sympathetic afferent reflex when therapy is administered to the PVN. The administration of an angiotensin receptor blocker by injection into the AP activates the sympatho-inhibitory baroreflex indicating that receptor blockers act by increasing parasympathetic activity. In chronic HF, in peripheral regions, angiotensin II elevates both norepinephrine release and synthesis and inhibits norepinephrine uptake at nerve endings, which may contribute to the increase in sympathetic nerve activity. Increased circulating angiotensin II during chronic HF may enhance the sympatho-excitatory chemoreflex and inhibit the sympatho-inhibitory baroreflex resulting in worsening of HF. Increased circulating angiotensin II signaling can directly act on the central nervous system via the subfornical organ and the AP to increase sympathetic outflow resulting in to neurohumoral dysfunction, resulting in to heart failure.

Topics: Angiotensin II; Angiotensin Receptor Antagonists; Animals; Baroreflex; Brain; Cardiomegaly; Chronic Disease; Heart; Heart Failure; Humans; Inflammation; Natriuretic Peptide, Brain; Neuroimmunomodulation; Norepinephrine; Oxidative Stress; Paraventricular Hypothalamic Nucleus; Peptide Fragments; Renin-Angiotensin System; Sympathetic Nervous System; Vagus Nerve Stimulation

The discovery of cardiac hormone production significantly changed the evaluation of the function of the heart, which is rather regarded as a determining factor of the electrolyte and hemodynamic homeostasis cooperating with other organ systems instead of a mechanical pump. The most important hormones produced by the heart are the natriuretic peptides that have the primary role of protection against volume overload through natriuretic, diuretic, vasodilator and antiproliferative effects. They are integrative markers of the cardiac, vascular and renal functions and marking cardiorenal distress. Brain natriuretic peptide and the N-terminal pro-hormone (NT-proBNP) became generally accepted markers of heart failure exceeding traditional pathophysiological significance of those. They are useful in the diagnosis, estimation of prognosis and therapy guidance and their therapeutic administration is also available. Although the detection of extraadrenal aldosterone production is an exciting new discovery, intracardial aldosterone production is not significant in human beings. The intracardial thyroid hormone production is regulated by deiodinase activity. The role of elevated T3 concentration was suggested in the development of cardiac hypertrophy, while low T3 is assumed to be important in adaptation to hypoxia. An unexpected, complex relation can be determined between epicardial adipose tissue and coronary artery diseases, cytokine and adipokine production of adipocytes might be a part of the self-enhancing process of atherosclerosis.

Topics: Adipocytes; Adipokines; Aldosterone; Biomarkers; Cardiomegaly; Coronary Artery Disease; Cytokines; Heart Failure; Humans; Intra-Abdominal Fat; Myocardium; Natriuretic Peptide, Brain; Peptide Fragments; Pericardium; Triiodothyronine

Atrial natriuretic peptide (ANP) and brain (B-type) natriuretic peptide (BNP) are circulating hormones of cardiac origin that play an important role in the regulation of intravascular blood volume and vascular tone. The plasma concentrations of ANP and BNP are elevated in heart failure, and they are considered to compensate for heart failure because of their diuretic, natriuretic, and vasodilating actions and inhibitory effects on renin and aldosterone secretion. Evidence is also accumulating from recent work that ANP and BNP exert their cardioprotective functions not only as circulating hormones but also as local autocrine and/or paracrine factors. In studies using cultured neonatal myocytes and fibroblasts, exogenous administration of both ANP and ANP antagonists demonstrated that ANP has antihypertrophic and antifibrotic functions. Corroborating these in vitro results, mice lacking natriuretic receptor-A (NPR-A), the receptor for ANP and BNP, develop cardiac hypertrophy and fibrosis independent of their blood pressure. Recent studies also suggest that the intracardiac natriuretic peptides/cGMP system plays a counter-regulatory role against the intracardiac renin-angiotensin-aldosterone system and TGF-beta mediated pathway. In a clinical setting, human recombinant ANP and BNP may be used for a therapy of heart failure; however, further evaluation is required in the future.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Heart Failure; Humans; Mice; Mice, Knockout; Models, Animal; Myocardium; Natriuretic Peptide, Brain; Natriuretic Peptides; Receptors, Atrial Natriuretic Factor; Renin-Angiotensin System; Signal Transduction

It is well-recognized that atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) are raised in conditions with ventricular volume and pressure overload. In addition to this established role in left ventricular congestive cardiac failure, there is good evidence that BNP has a diagnostic role in right ventricular (RV) dysfunction and pulmonary arterial hypertension (PAH). For example, BNP levels can be used to differentiate between dyspneic patients with pure respiratory defects and those with RV dysfunction. Studies in patients with PAH have demonstrated significant correlations between BNP levels and mean pulmonary arterial pressure as well as pulmonary vascular resistance. Additionally, BNP has a prognostic role in patients with RV pressure overload and pulmonary hypertension, and it offers a noninvasive test that can be used to guide therapy in patients with PAH. However, although measured plasma proBNP levels are raised in conditions with RV overload, its biological significance is still not well-understood. In this article, we review the general physiologic and potential therapeutic role of natriuretic peptides in respiratory disease, RV dysfunction, and PAH. Furthermore, we assess the various clues toward natriuretic peptide action coming from laboratory studies. ANP and BNP knockout mice develop cardiac fibrosis and hypertrophy. Potentiation of the natriuretic pathway has been shown to reduce cardiac hypertrophy and PAH. This is likely to take place as a result of increased intracellular cyclic guanosine monophosphate levels and subsequent pulmonary vasorelaxant activity. In view of this evidence, there may be a rationale for the therapeutic use of recombinant BNP or neutral endopeptidase inhibitors under conditions of RV dysfunction and PAH.

Topics: Animals; Atrial Natriuretic Factor; Biomarkers; Cardiomegaly; Fibrosis; Heart Ventricles; Humans; Hypertension, Pulmonary; Natriuretic Peptide, Brain; Ventricular Dysfunction, Right; Ventricular Pressure

Within the last five years, assay systems for measurement of plasma levels of brain natriuretic peptide (BNP) have been approved as a diagnostic aid for heart failure (HF). Similarly, nesiritide, a recombinant form of human BNP, has been approved for the treatment of acutely decompensated HF. Both BNP as a diagnostic test and a therapeutic modality are rapidly becoming integrated into clinical practice. The purpose of this review is to provide a brief overview of the physiology of the natriuretic peptides relevant to their informed clinical use. The current literature regarding the utility of measuring BNP for the diagnosis and management of HF is reviewed and practical recommendations regarding the interpretation of BNP levels are offered. The clinical literature regarding the use of recombinant BNP for the treatment of HF is reviewed, underscoring current gaps in our knowledge regarding the indications for and benefits of this novel agent.

Topics: Atrial Natriuretic Factor; Cardiomegaly; Diuresis; Heart Failure; Humans; Kidney; Myocardial Infarction; Natriuresis; Natriuretic Agents; Natriuretic Peptide, Brain; Natriuretic Peptide, C-Type; ROC Curve; Survival Analysis; Treatment Outcome; Vasodilation; Ventricular Remodeling

1. If one was to design a hormone to protect the heart, it would have a number of features shown by the cardiac natriuretic peptides atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP). These hormones are made in cardiomyocytes and are released into the circulation in response to atrial and ventricular stretch, respectively. Atrial natriuretic peptide and BNP can reduce the preload and after-load in normal and failing hearts. They reduce blood volume over the short term by sequestering plasma and over the longer term by promoting renal salt and water excretion and by antagonizing the renin-angiotensin-aldosterone system at many levels. Each of these actions affords indirect benefit to a volume- or pressure-threatened heart. 2. Recent studies have identified additional modes of action of the natriuretic peptides that may also confer cardioprotective benefits, especially in heart disease. The emerging findings are: (i) that ANP and BNP antagonize the cardiac hypertrophic action of angiotensin II and continue working under conditions where endothelial nitric oxide (NO) function is compromised, such as in the presence of high glucose in diabetes; (ii) they potentiate the bradycardia caused by inhibitory ('autoprotective') cardio-cardiac reflexes; and, furthermore, (iii) BNP can suppress cardiac sympathetic nerve activity in humans, including those with heart failure. Thus, it appears that natriuretic peptides can shift sympathovagal balance in a beneficial direction (away from the sympathetic). The vagal reflex and antihypertrophic actions of the peptides are mediated by particulate guanylyl cyclase (pGC) natriuretic peptide receptors. 3. The multiple synergistic actions of the natriuretic peptides make them and their pGC receptors attractive targets for therapy in heart disease. Encouragingly, exogenous natriuretic peptides remain effective even when endogenous peptide levels are raised, as is the case in heart failure. They also remain effective in disease states where other protective mechanisms, such as the NO system, have become ineffective, offering yet further encouragement for the therapeutic use of the natriuretic peptides.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Cardiovascular Diseases; Heart; Hormones; Humans; Natriuretic Peptide, Brain; Sympathetic Nervous System; Vagus Nerve

There is no information on heart failure (HF) with preserved ejection fraction (HFpEF, EF >50%) in children.. Through a retrospective review of 3,907 pediatric patients with cardiovascular disease, we examined the characteristics of pediatric HFpEF over a 10-year period. We identified 18 patients with HFpEF (0.5%). They were predominantly young children (1.1±0.9 years, no sex preponderance), who had undergone surgery for congenital heart disease. They also had concentric hypertrophy and diastolic dysfunction with elevated blood pressure. Notably, HFpEF patients had more pronounced elevation of serum aldosterone but less pronounced elevation of plasma brain natriuretic peptide (BNP) than 22 systolic HF patients (SHF, EF ≤50%) (aldosterone: 1,375±1,200 vs. 511±563pg/ml, P<0.05, and BNP: 101±141 vs. 749±818pg/ml, P<0.005). Consequently, the aldosterone/BNP ratio was significantly higher in HFpEF (38±63) than in SHF (1.7±1.9, P<0.05), and an aldosterone/BNP ratio of 10.3 or higher best predicted HFpEF (area under the curve=0.89). The HF mortality rate was significantly lower in the HFpEF than in the SHF cases, and HF symptoms showed amelioration in 61% of patients during the follow-up period of 4.2±2.6 years.. HFpEF does exist in children. A common pathophysiology underlies childhood and adult HFpEF despite considerable epidemiological and etiological differences. Future controlled studies are warranted to assess the cause-effect relationship between unique hormonal profiles and HFpEF.

Topics: Adolescent; Adult; Age Factors; Aldosterone; Cardiomegaly; Child; Child, Preschool; Disease-Free Survival; Female; Follow-Up Studies; Heart Defects, Congenital; Heart Failure; Humans; Infant; Male; Natriuretic Peptide, Brain; Retrospective Studies; Stroke Volume; Survival Rate

We evaluated the diagnostic significance of the N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentration in asymptomatic cats with cardiac enlargement. The plasma NT-proBNP concentration was measured in 21 clinically healthy control cats, and 67 asymptomatic cats with cardiac enlargement defined as end-diastolic interventricular septum thickness (IVSd) and/or diastolic left ventricular posterior wall thickness (LVPWd) >0.6 cm, vertebla heart scale (VHS) >7.8, and/or left atria/aorta ratio (LA/Ao) >1.5. The plasma NT-proBNP concentration in the asymptomatic cats with cardiac enlargement (median: 662.0, range: 24.0-2,449.0 pmol/l) was significantly higher than that in the controls (24.0, 24.0-95.0 pmol/l, P<0.001). The plasma NT-proBNP concentration was significantly correlated with the VHS, LA/Ao, IVSd and LVPWd (r=0.578, P<0.001; r=0.462, P<0.001; r=0.563, P<0.001; and r=0.764, P<0.001, respectively). Receiver operating characteristic analysis showed a cut-off value of 95.0 pmol/l for the detection of asymptomatic cats with cardiac enlargement, sensitivity and specificity of 88.1 and 100%, respectively, and an area under the curve of 0.971. These results suggest that the determination of the plasma NT-proBNP concentration can be a useful screening test for asymptomatic cats with cardiac enlargement.

Topics: Animals; Asymptomatic Diseases; Biomarkers; Cardiomegaly; Cat Diseases; Cats; Female; Male; Natriuretic Peptide, Brain; Peptide Fragments; ROC Curve; Sensitivity and Specificity; Ultrasonography

Toll-like receptor 4 (TLR4) recognizes lipopolysaccharides and endogenous ligands released after organ injury. Deficiency of TLR4 attenuates the development of left ventricular hypertrophy after transverse aortic constriction (TAC) in mice. We hypothesized that application of the TLR4 antagonist eritoran may also reduce cardiac hypertrophy after TAC surgery.. A catheter was implanted into the jugular vein of C57BL/6 mice to allow repeated administration of eritoran (5 mg/kg body weight) or placebo. Three days after TAC or sham surgery, heart weights were determined and cardiac tissue underwent mRNA and protein quantification. The TAC placebo group exhibited a significant increase in left ventricular weight, left ventricular weight/tibia length, and left ventricular/body weight ratio compared with the sham and TAC eritoran groups. Natriuretic peptide mRNA was elevated significantly only in TAC placebo mice. Transverse aortic constriction surgery led to a distinct increase in interleukin (IL)-1β and IL-6 mRNA and protein expression in the placebo but not the eritoran group. In contrast, IL-10 was significantly increased in both eritoran groups independent from TAC. Matrix metalloproteinase zymographic activity was highest in TAC placebo animals.. Application of the TLR4 antagonist eritoran attenuates the development of cardiac hypertrophy possibly by a reduction in inflammatory and increase in anti-inflammatory cytokines.

Topics: Animals; Cardiomegaly; Disaccharides; Disease Models, Animal; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Interleukins; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Natriuretic Peptide, Brain; Reverse Transcriptase Polymerase Chain Reaction; Sugar Phosphates; Toll-Like Receptor 4

Adiponectin exerts cardiovascular protective actions, although some studies have shown the opposite. In hemodialysis, obese subjects display lower mortality rates despite hypoadiponectinemia, while higher adiponectin concentrations correlate with an elevated cardiovascular risk in nonobese subjects. The aim of the study is to suggest that adiponectin level variations are associated with differences in the body mass index (BMI). The interplay between adiponectin and pro-brain natriuretic peptide (Pro-BNP) levels may vary according to body fat mass. Fifty-two chronic hemodialysis patients were divided into three groups. Group A, BMI<25 (n=20); Group B, BMI 25 to 30 (n=21), and Group C, BMI>30 (n=11). Diabetics: Group A 10%; Group B 6 29%; Group C 55%, P=0.027. Determinations: Adiponectin, Pro-BNP, insulin, insulin resistance (HOMA), troponin T, nutritional status, ultrafiltration rates, C-reactive protein (CRP), vascular accesses, and echocardiography. Group A: adiponectinemia positively and significantly correlated with Pro-BNP, CRP, and troponin T. As BMI increased, adiponectin, Pro-BNP, and malnutrition significantly decreased, while insulin, HOMA, and ultrafiltration rates significantly increased. Cardiac restriction was significantly higher in obese patients. In all groups, Pro-BNP and troponin T displayed a strong positive correlation. In low-BMI subjects, high Pro-BNP and adiponectin, low myocardial restriction, and worse nutritional status were prevalent. In obesity, hypoadiponectinemia stimulates cardiac remodeling, cardiac hypertrophy, and decreased stretching, rendering Pro-BNP levels low despite high ultrafiltration rates. Thus, adiponectin correlates inversely with BMI, probably playing different cardiovascular roles as BMI changes.

Topics: Adiponectin; Aged; Aged, 80 and over; Body Mass Index; Cardiomegaly; Cross-Sectional Studies; Female; Humans; Insulin Resistance; Male; Middle Aged; Natriuretic Peptide, Brain; Obesity; Prospective Studies; Renal Dialysis

We analyzed quantitative echocardiographic data from a large heart failure cohort receiving medical and cardiac resynchronization therapy (CRT) to determine baseline predictors of progressive left ventricular (LV) enlargement.. Quantitative echocardiograms were obtained at baseline and after 6 months in 776 outpatients with chronic heart failure who participated in MIRACLE (Multicenter InSync Randomized Clinical Evaluation) and MIRACLE-ICD (Multicenter InSync ICD Randomized Clinical Evaluation). We used multivariable regression to determine clinical, therapeutic, and echocardiographic characteristics that predicted a subsequent change in left ventricular end-diastolic volume (LVEDV). Over 6 months, LVEDV increased in 308 (40%) and decreased in 468 (60%) patients. Baseline mitral regurgitation and levels of plasma brain natriuretic peptide (BNP) independently predicted LV enlargement, whereas CRT predicted a decrease in LVEDV (all P < .01). In all models tested, male gender was an independent risk factor for progressive LV enlargement (P < .0001).. Men show more prominent LV dilation than women in chronic heart failure despite medical and device therapy. Rates of LV remodeling are influenced further by mitral regurgitation, plasma BNP, and CRT. Future studies should take these clinical factors into account when determining the influence of genetic factors and novel therapies on ventricular remodeling in chronic heart failure.

Topics: Aged; Cardiac Pacing, Artificial; Cardiomegaly; Disease Progression; Female; Heart Failure; Humans; Male; Middle Aged; Mitral Valve Insufficiency; Natriuretic Peptide, Brain; Sex Factors; Ventricular Dysfunction, Left; Ventricular Remodeling

Since growth hormone (GH) has proven beneficial in experimental heart failure, and the natural history of Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) is frequently complicated by the development of dilated cardiomyopathy, we administered GH to six patients with DMD and 10 with BMD, with the evidence of cardiac involvement.. Patients were randomized to receive for 3 months either placebo or recombinant human GH, in a double-blind fashion. In GH-treated patients, left ventricular (LV) mass increased by 16% in BMD and by 29% in DMD (both p<0.01), with a significant increase of relative wall thickness (+19%). Systemic blood pressure remained unchanged, while LV end-systolic stress fell significantly by 13% in BMD and by 33% in DMD, with a slight increase of systolic function indexes. No changes were observed related to cardiac arrhythmias and skeletal muscle function in the patient groups during the treatment period, nor any side effects were observed. Brain natriuretic peptide, interleukin-6, and tumor necrosis factor-alpha circulating levels were elevated at baseline. While brain natriuretic peptide decreased by 40%, cytokine levels did not exhibit significant variations during the treatment period.. The 3-month GH therapy in patients with DMD and BMD induces a hypertrophic response associated with a significant reduction of brain natriuretic peptide plasma levels and a slight improvement of systolic function, no changes in skeletal muscle function, and no side effects.

Topics: Adolescent; Adult; Analysis of Variance; Cardiomegaly; Child; Double-Blind Method; Electrocardiography; Heart Diseases; Human Growth Hormone; Humans; Insulin-Like Growth Factor I; Interleukin-6; Lung; Male; Middle Aged; Muscle, Skeletal; Muscular Dystrophy, Duchenne; Natriuretic Peptide, Brain; Regression Analysis; Tumor Necrosis Factor-alpha

Excessive activation of the sympathetic nervous system is involved in cardiovascular damage including cardiac hypertrophy. Natriuretic peptides are assumed to exert protective actions for the heart, alleviating hypertrophy and/or fibrosis of the myocardium. In contrast to this assumption, we show in the present study that both atrial and C-type natriuretic peptides (ANP and CNP) potentiate cardiac hypertrophic response to noradrenaline (NA) in rats. Nine-week-old male Wistar rats were continuously infused with subcutaneous 30 micro-g/h NA without or with persistent intravenous administration of either 1.0 micro-g/h ANP or CNP for 14 days. Blood pressure (BP) was recorded under an unrestrained condition by a radiotelemetry system. Cardiac hypertrophic response to NA was evaluated by heart weight/body weight (HW/BW) ratio and microscopic measurement of myocyte size of the left ventricle. Mean BP levels at the light and dark cycles rose by about 20 mmHg following NA infusion for 14 days, with slight increases in HW/BW ratio and ventricular myocyte size. Infusions of ANP and CNP had no significant effects on mean BP in NA-infused rats, while two natriuretic peptides potentiated cardiac hypertrophic response to NA. Cardiac hypertrophy induced by co-administration of NA and ANP was attenuated by treatment with prazosin or atenolol. In summary, both ANP and CNP potentiated cardiac hypertrophic effect of continuously infused NA in rats, suggesting a possible pro-hypertrophic action of natriuretic peptides on the heart.

Topics: Animals; Atrial Natriuretic Factor; Blood Pressure; Cardiomegaly; Male; Natriuretic Peptide, Brain; Natriuretic Peptide, C-Type; Norepinephrine; Rats; Rats, Wistar

The study aimed to evaluate the therapeutic effect of nilotinib-loaded biocompatible gelatin methacryloyl (GelMA) microneedles patch on cardiac dysfunction after myocardial infarction(MI), and provide a new clinical perspective of myocardial fibrosis therapies. The GelMA microneedles patches were attached to the epicardial surface of the infarct and peri-infarct zone in order to deliver the anti-fibrosis drug nilotinib on the 10th day after MI, when the scar had matured. Cardiac function and left ventricular remodeling were assessed by such as echocardiography, BNP (brain natriuretic peptide) and the heart weight/body weight ratio (HW/BW). Myocardial hypertrophy and fibrosis were examined by WGA (wheat germ agglutinin) staining, HE (hematoxylin-eosin staining) staining and Sirius Red staining. The results showed that the nilotinib-loaded microneedles patch could effectively attenuate fibrosis expansion in the peri-infarct zone and myocardial hypertrophy, prevent adverse ventricular remodeling and finally improve cardiac function. This treatment strategy is a beneficial attempt to correct the cardiac dysfunction after myocardial infarction, which is expected to become a new strategy to correct the cardiac dysfunction after MI. This is of great clinical significance for improving the long-term prognosis of MI patients.. 本研究旨在评价负载尼洛替尼的生物相容性甲基丙烯酰化明胶（GelMA）微针贴片应用于心肌梗死（简称：心梗）后对心脏功能障碍的治疗作用，为临床抗心肌纤维化治疗提供新的思路。本研究在心梗造模后10 d（疤痕成熟期），将GelMA微针贴片贴附于心外膜表面，靶向梗死及周围区递送抗纤维化药物尼洛替尼。在心梗造模后28 d，通过超声心动图、血浆脑型利钠肽、心重/体重比等指标评价心脏功能和左室重构情况；通过小麦胚芽凝集素染色评价心肌肥大情况；通过苏木精—伊红染色、天狼星红染色评价心肌纤维化情况。结果显示，相较于心梗对照组及使用空白GelMA微针贴片治疗组，负载尼洛替尼的GelMA微针贴片可减轻心肌肥大和梗死周围区纤维化过度扩张，从而预防不良心室重构，改善心功能。本研究所提这一治疗策略是纠正心梗后心脏功能障碍的一次有益尝试，有望成为纠正心梗后心脏功能障碍的新策略，对改善心梗患者的长期预后具有重要的临床意义。.

Topics: Cardiomegaly; Fibrosis; Humans; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Cyclooctanes; Echocardiography; Heart Failure; Heart Ventricles; Isoproterenol; Lignans; Male; Mice; Mice, Inbred C57BL; MicroRNAs; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Polycyclic Compounds; Rats; Rats, Sprague-Dawley; Signal Transduction; Ventricular Function, Left

Midkine levels are related to various diseases, including cardiovascular disease, renal disease and autoimmune disease. The research aimed to investigate the mitigation influence of downregulation of intermediate factors on myocardial hypertrophy induced by angiotensin Ⅱ (Ang), and whether downregulation of midkine could attenuate oxidative stress and autophagy. Induced myocardial hypertrophy of the mice model and treated HL-1 cells with Ang Ⅱ in vitro. The expressions of midkine were increased in the model and HL-1 cells with Ang II treatment. Midkine silence alleviated cardiac hypertrophy induced by Ang II, and inhibited the increases of atrial natriuretic peptide (ANP), Brain natriuretic peptide (BNP) and beta-myosin heavy chain (β-MHC) in the heart of mice. The raises of ANP, BNP and β-MHC in Ang II-induced HL-1 cells were also suppressed after midkine downregulation. Downregulating of midkine inhibited the increases of oxidative stress markers 8-OHdG, superoxide anions and MDA in the heart of mice or in the Ang II-treated HL-1 cells. The raises of LC3B, Atg3, Atg5 and Beclin1 in mice heart and in the Ang II.-induced HL-1 cells were attenuated after midkine silence. These outcomes showed that midkine was upregulated in myocardial hypertrophy mice. Targeting of midkine could alleviate cardiac hypertrophy via attenuation of oxidative stress and autophagy.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Autophagy; Cardiomegaly; Mice; Midkine; Myocytes, Cardiac; Natriuretic Peptide, Brain; Oxidative Stress

Cardiac hypertrophy is an adaptive and compensatory mechanism preserving cardiac output during detrimental stimuli. Circular RNAs (circRNAs) have been illustrated to exert important implications in the pathogenesis of multiple cardiovascular diseases (CVD) including demonstrated cardiac hypertrophy. Toll-like receptor 4 (TLR4) has been previously reported to be a crucial regulator in inflammatory response and cardiac hypertrophy. However, the role of circular isoforms derived from TLR4 in cardiac hypertrophy remains unclear.. Expression of circ-TLR4 and TLR4 in cardiomyocytes was detected by RT-qPCR. The indicators of cardiac hypertrophy responses, including cell surface area, atrial natriuretic factor (ANF), B-type natriuretic peptide (BNP) and β-myosin heavy chain (β-MHC) were measured by immunofluorescence staining and western blot. RIP assay was used to validate the interaction between circ-TLR4 and TLR4.. Circ-TLR4 and TLR4 was up-regulated in cellular models of cardiac hypertrophy. Circ-TLR4 knockdown attenuated angiotensin II (Ang II)-induced hypertrophy responses in cardiomyocytes. Moreover, circ-TLR4 positively regulated TLR4 expression through recruiting FUS to stabilize TLR4 mRNA. Furthermore, TLR4 overexpression rescued the cardiac responses mediated by circ-TLR4 silencing.. Circ-TLR4 promotes cardiac hypertrophy through recruiting FUS to stabilize TLR4 mRNA.

Topics: Angiotensin II; Atrial Natriuretic Factor; Cardiomegaly; Humans; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; RNA-Binding Protein FUS; RNA, Circular; RNA, Messenger; Toll-Like Receptor 4

Recent studies have demonstrated that hyperglycemia is a major risk factor for the development and exacerbation of cardiovascular disease (CVD). However, the molecular mechanisms involved in diabetic cardiomyopathy (DCM) have not been fully elucidated. In this study, we focused on the underlying mechanism of DCM. Leptin receptor-deficient db/db mice were used to model a type 2 diabetes mellitus (T2DM) model in our study. WT mice and db/db mice received 4-phenylbutyric acid (4-PBA) (25 mg/kg/day) and saline by intraperitoneal injection every other day for 4 weeks. WT and db/db mice were given tail vein injections of 100 μL of rAAV9-Sh-MAPK10 and rAAV9-Sh-GFP at the age of 6-8 weeks. Echocardiography was performed to measure cardiac function, histological examinations were used to evaluate ventricular hypertrophy and fibrosis. Quantitative RT-qPCR was used to assess the mRNA expression of Jun N-terminal kinase 3 (JNK3, MAPK10), atrial natriuretic factor (ANF), brain natriuretic peptide (BNP), and collagen I and III. Immunoblotting was performed to measure the levels of cardiac hypertrophy-related proteins, fibrosis-related proteins, endoplasmic reticulum stress (ERS)-related proteins and apoptosis-related proteins. TUNEL staining was performed to examine cardiomyocyte apoptosis. In contrast to 12-week-old db/db mice, 16-week-old db/db mice showed the most severe myocardial dysfunction. The DCM induced by hyperglycemia was largely alleviated by 4-PBA (25 mg/kg/day, intraperitoneal injection). Similarly, tail vein injection of rAAV9-Sh-MAPK10 reversed the phenotype of the heart in db/db mice including cardiac hypertrophy and apoptosis in db/db mice. The mechanistic findings suggested that hyperglycemia initiated the ERS response through the negative regulation of sirtuin 1 (SIRT1), leading to the occurrence of myocardial dysfunction, and specific knockdown of MAPK10 in the heart directly reversed myocardial dysfunction induced by hyperglycemia. We demonstrated that hyperglycemia promotes DCM in db/db mice through the ERS-MAPK10 signaling pathway in diabetic mice.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Cardiomyopathies; Collagen; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Endoplasmic Reticulum Stress; Fibrosis; Hyperglycemia; JNK Mitogen-Activated Protein Kinases; Mice; Mitogen-Activated Protein Kinase 10; Natriuretic Peptide, Brain; Receptors, Leptin; RNA, Messenger; Signal Transduction; Sirtuin 1

G protein-coupled receptors (GPCRs) are the largest family of membrane receptors that mediate the effects of cardiac diseases. GPR30, also named G-protein-coupled estrogen receptor, shows beneficial effect on female patients with heart failure. This research aimed to probe the role and mechanism of GPR30 in myocardial hypertrophy. The model of cardiac hypertrophy was induced by infusion of angiotensin (Ang) II in mice, and was induced by Ang II treatment in neonatal rat cardiomyocyte (NRCM). The mouse model of myocardial hypertrophy was induced by angiotensin (Ang) Ⅱ, and the neonatal rat cardiomyocyte (NRCM) was induced by Ang Ⅱ treatment. GPR30 agonist G1 reduced cardiac hypertrophy induced by Ang II in mice, and reduced cardiac atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and β-myosin heavy chain (β-MHC) induced by Ang II. Ang Ⅱ treatment of myocardial fibrosis in mice was suppressed after administration of G1. GPR30 deficiency produced the opposite results. Oxidative stress and apoptosis were enhanced in the mice heart induced by Ang II, which were suppressed by G1 administration, but were further exacerbated after GPR30 deficiency. The outcomes demonstrated that GPR30 participated in the regulation of cardiac hypertrophy and fibrosis. Activation of GPR30 ameliorated cardiac hypertrophy and fibrosis by reducing oxidative stress and apoptosis.

Topics: Angiotensin II; Animals; Apoptosis; Atrial Natriuretic Factor; Cardiomegaly; Female; Fibrosis; GTP-Binding Proteins; Mice; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Oxidative Stress; Peptide Hormones; Rats; Receptors, Estrogen; Receptors, G-Protein-Coupled

A-kinase anchoring protein 5 (AKAP5) is involved in ventricular remodeling in rats with heart failure after myocardial infarction; however, the specific mechanism is not clear. This study investigated whether AKAP5 anchors calcineurin (CaN) to regulate the remodeling of H9c2 cardiomyocytes.. H9c2 cells were subjected to hypoxia stress for 3 h and reoxygenation for 24 h to create a hypoxia-reoxygenation (H/R) model. These cells were divided into three groups: H/R (model), empty vector +H/R (NC), and siRNA-AKAP5+H/R (siRNA-AKAP5) groups. The non-H/R H9c2 cells were used as normal controls. Western blotting was used to detect cardiac hypertrophy-related protein expression in the cells, including atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), beta myosin heavy chain (β-MHC), and phosphorylated nuclear factor of activated T-cell 3 (p-NFATc3). Phalloidin staining was used to label the cytoskeleton and the cell area in different groups was measured. Immunofluorescence staining and coimmunoprecipitation were used to study the relationship between AKAP5 and CaN. H9c2 cells pretreated with the CaN inhibitor FK506 were used to further verify the relationship between AKAP5 and CaN.. In the siRNA-AKAP5+H/R group, the expression level of cardiac hypertrophy-related proteins (ANP, BNP, and β-MHC) and CaN and the area of cardiomyocytes were significantly increased, while the p-NFATc3/NFATc3 ratio was decreased in H9c2H/R cells. AKAP5 and CaN proteins were colocalized and interacted in the cells. The CaN inhibitor significantly suppressed the expression of CaN, increased the p-NFATc3/NFATc3 ratio, and reduced the expression levels of ANP, BNP, and β-MHC proteins in the cells with low AKAP5 expression.. AKAP5 downregulation aggravated the remodeling of cardiomyocytes after H/R. AKAP5 may anchor CaN to form a complex, which in turn activates NFATc3 dephosphorylation and expression of hypertrophy-related proteins.

Topics: A Kinase Anchor Proteins; Animals; Atrial Natriuretic Factor; Calcineurin; Cardiomegaly; Hypoxia; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Phalloidine; Rats; RNA, Small Interfering; Tacrolimus

MicroRNA 34a (miR-34a) is elevated in the heart in a setting of cardiac stress or pathology, and we previously reported that inhibition of miR-34a in vivo provided protection in a setting of pressure overload-induced pathological cardiac hypertrophy and dilated cardiomyopathy. Prior work had also shown that circulating or cardiac miR-34a was elevated in a setting of diabetes. However, the therapeutic potential of inhibiting miR-34a in vivo in the diabetic heart had not been assessed. In the current study, type 1 diabetes was induced in adult male mice with 5 daily injections of streptozotocin (STZ). At 8 weeks post-STZ, when mice had established type 1 diabetes and diastolic dysfunction, mice were administered locked nucleic acid (LNA)-antimiR-34a or saline-control with an eight-week follow-up. Cardiac function, cardiac morphology, cardiac fibrosis, capillary density and gene expression were assessed. Diabetic mice presented with high blood glucose, elevated liver and kidney weights, diastolic dysfunction, mild cardiac enlargement, cardiac fibrosis and reduced myocardial capillary density. miR-34a was elevated in the heart of diabetic mice in comparison to non-diabetic mice. Inhibition of miR-34a had no significant effect on diastolic function or atrial enlargement, but had a mild effect on preventing an elevation in cardiac enlargement, fibrosis and ventricular gene expression of B-type natriuretic peptide (BNP) and the anti-angiogenic miRNA (miR-92a). A miR-34a target, vinculin, was inversely correlated with miR-34a expression, but other miR-34a targets were unchanged. In summary, inhibition of miR-34a provided limited protection in a mouse model with established type 1 diabetes-induced cardiomyopathy and failed to improve diastolic function. Given diabetes represents a systemic disorder with numerous miRNAs dysregulated in the diabetic heart, as well as other organs, strategies targeting multiple miRNAs and/or earlier intervention is likely to be required.

Topics: Animals; Blood Glucose; Cardiomegaly; Cardiomyopathy, Dilated; Diabetes Mellitus, Type 1; Disease Models, Animal; Fibrosis; Male; Mice; Mice, Inbred Strains; MicroRNAs; Natriuretic Peptide, Brain; Streptozocin; Vinculin

Modified citrus pectin (MCP) is a specific inhibitor of galectin-3 (Gal-3) that is regarded as a new biomarker of cardiac hypertrophy, but its effect is unclear. The aim of this study is to investigate the role and mechanism of MCP in isoproterenol (ISO)-induced cardiac hypertrophy. Rats were injected with ISO to induce cardiac hypertrophy and treated with MCP. Cardiac function was detected by ECG and echocardiography. Pathomorphological changes were evaluated by the haematoxylin eosin (H&E) and wheat germ agglutinin (WGA) staining. The hypertrophy-related genes for atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and β-myosin heavy chain (β-MHC), and the associated signal molecules were analysed by qRT-PCR and western blotting. The results show that MCP prevented cardiac hypertrophy and ameliorated cardiac dysfunction and structural disorder. MCP also decreased the levels of ANP, BNP, and β-MHC and inhibited the expression of Gal-3 and Toll-like receptor 4 (TLR4). Additionally, MCP blocked the phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3), but it promoted the phosphorylation of p38. Thus, MCP prevented ISO-induced cardiac hypertrophy by activating p38 signalling and inhibiting the Gal-3/TLR4/JAK2/STAT3 pathway.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Cardiovascular Agents; Disease Models, Animal; Galectin 3; Isoproterenol; Janus Kinase 2; Male; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; p38 Mitogen-Activated Protein Kinases; Pectins; Phosphorylation; Rats, Wistar; Signal Transduction; STAT3 Transcription Factor; Toll-Like Receptor 4; Ventricular Function, Left; Ventricular Remodeling

Pathological cardiac remodelling is characterized by cardiomyocyte (CM) hypertrophy and fibroblast activation, which can ultimately lead to maladaptive hypertrophy and heart failure (HF). Genome-wide expression analysis on heart tissue has been instrumental for the identification of molecular mechanisms at play. However, these data were based on signals derived from all cardiac cell types. Here, we aimed for a more detailed view on molecular changes driving maladaptive CM hypertrophy to aid in the development of therapies to reverse pathological remodelling.. Utilizing CM-specific reporter mice exposed to pressure overload by transverse aortic banding and CM isolation by flow cytometry, we obtained gene expression profiles of hypertrophic CMs in the more immediate phase after stress, and CMs showing pathological hypertrophy. We identified subsets of genes differentially regulated and specific for either stage. Among the genes specifically up-regulated in the CMs during the maladaptive phase we found known stress markers, such as Nppb and Myh7, but additionally identified a set of genes with unknown roles in pathological hypertrophy, including the platelet isoform of phosphofructokinase (PFKP). Norepinephrine-angiotensin II treatment of cultured human CMs induced the secretion of N-terminal-pro-B-type natriuretic peptide (NT-pro-BNP) and recapitulated the up-regulation of these genes, indicating conservation of the up-regulation in failing CMs. Moreover, several genes induced during pathological hypertrophy were also found to be increased in human HF, with their expression positively correlating to the known stress markers NPPB and MYH7. Mechanistically, suppression of Pfkp in primary CMs attenuated stress-induced gene expression and hypertrophy, indicating that Pfkp is an important novel player in pathological remodelling of CMs.. Using CM-specific transcriptomic analysis, we identified novel genes induced during pathological hypertrophy that are relevant for human HF, and we show that PFKP is a conserved failure-induced gene that can modulate the CM stress response.

Topics: Animals; Cardiac Myosins; Cardiomegaly; Cells, Cultured; Disease Models, Animal; Fibrosis; Gene Expression Profiling; Gene Expression Regulation; Humans; Male; Mice, Inbred C57BL; Mice, Transgenic; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Phosphofructokinase-1, Type C; Transcriptome; Ventricular Remodeling

Accidental bromine spills are common and its large industrial stores risk potential terrorist attacks. The mechanisms of bromine toxicity and effective therapeutic strategies are unknown. Our studies demonstrate that inhaled bromine causes deleterious cardiac manifestations. In this manuscript we describe mechanisms of delayed cardiac effects in the survivors of a single bromine exposure. Rats were exposed to bromine (600 ppm for 45 min) and the survivors were sacrificed at 14 or 28 days. Echocardiography, hemodynamic analysis, histology, transmission electron microscopy (TEM) and biochemical analysis of cardiac tissue were performed to assess functional, structural and molecular effects. Increases in right ventricular (RV) and left ventricular (LV) end-diastolic pressure and LV end-diastolic wall stress with increased LV fibrosis were observed. TEM images demonstrated myofibrillar loss, cytoskeletal breakdown and mitochondrial damage at both time points. Increases in cardiac troponin I (cTnI) and N-terminal pro brain natriuretic peptide (NT-proBNP) reflected myofibrillar damage and increased LV wall stress. LV shortening decreased as a function of increasing LV end-systolic wall stress and was accompanied by increased sarcoendoplasmic reticulum calcium ATPase (SERCA) inactivation and a striking dephosphorylation of phospholamban. NADPH oxidase 2 and protein phosphatase 1 were also increased. Increased circulating eosinophils and myocardial 4-hydroxynonenal content suggested increased oxidative stress as a key contributing factor to these effects. Thus, a continuous oxidative stress-induced chronic myocardial damage along with phospholamban dephosphorylation are critical for bromine-induced chronic cardiac dysfunction. These findings in our preclinical model will educate clinicians and public health personnel and provide important endpoints to evaluate therapies.

Topics: Animals; Bromine; Calcium-Binding Proteins; Cardiomegaly; Cardiotoxicity; Diastole; Disease Models, Animal; Fibrosis; Male; Mitochondria, Heart; Myocardium; NADPH Oxidase 2; Natriuretic Peptide, Brain; Oxidative Stress; Peptide Fragments; Phosphorylation; Protein Phosphatase 1; Rats, Sprague-Dawley; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Systole; Time Factors; Troponin I; Ventricular Dysfunction, Left; Ventricular Dysfunction, Right; Ventricular Function, Left; Ventricular Function, Right; Ventricular Remodeling

Metabolic shift is an important contributory factor for progression of hypertension-induced left ventricular hypertrophy into cardiac failure. Under hypertrophic conditions, heart switches its substrate preference from fatty acid to glucose. Prolonged dependence on glucose for energy production has adverse cardiovascular consequences. It was reported earlier that reactivation of fatty acid metabolism with medium chain triglycerides ameliorated cardiac hypertrophy, oxidative stress and energy level in spontaneously hypertensive rat. However, the molecular mechanism mediating the beneficial effect of medium chain triglycerides remained elusive. It was hypothesized that reduction of cardiomyocyte hypertrophy by medium chain fatty acid (MCFA) is mediated by modulation of signaling pathways over expressed in cardiac hypertrophy. The protective effect of medium chain fatty acid (MCFA) was evaluated in cellular model of myocyte hypertrophy. H9c2 cells were stimulated with Arginine vasopressin (AVP) for the induction of hypertrophy. Cell volume and secretion of brain natriuretic peptide (BNP) were used for assessment of cardiomyocyte hypertrophy. Cells were pretreated with MCFA (Caprylic acid) and metabolic modulation was assessed from the expression of medium-chain acyl-CoA dehydrogenase (MCAD), cluster of differentiation-36 (CD36) and peroxisome proliferator-activated receptor (PPAR)-α mRNA. The signaling molecules modified by MCFA was evaluated from protein expression of mitogen activated protein kinases (MAPK: ERK1/2, p38 and JNK) and Calcineurin A. Pretreatment with MCFA stimulated fatty acid metabolism in hypertrophic H9c2, with concomitant reduction of cell volume and BNP secretion. MCFA reduced activated ERK1/2, JNK and calicineurin A expression mediated by AVP. In conclusion, the beneficial effect of MCFA is possibly mediated by stimulation of fatty acid metabolism and modulation of MAPK and Calcineurin A.

Topics: Animals; Calcineurin; Caprylates; Cardiomegaly; CD36 Antigens; Cell Line; Fatty Acids; Glucose; Hypertension; Hypertrophy; Hypertrophy, Left Ventricular; Lipid Metabolism; Muscle Cells; Natriuretic Peptide, Brain; Oxidative Stress; Rats; Rats, Inbred SHR; Signal Transduction

Enhancers regulate gene expressions in a tissue- and pathology-specific manner by altering its activities. Plasma levels of atrial and brain natriuretic peptides, encoded by the Nppa and Nppb, respectively, and synthesized predominantly in cardiomyocytes, vary depending on the severity of heart failure. We previously identified the noncoding conserved region 9 (CR9) element as a putative Nppb enhancer at 22-kb upstream from the Nppb gene. However, its regulatory mechanism remains unknown. Here, we therefore investigated the mechanism of CR9 activation in cardiomyocytes using different kinds of drugs that induce either cardiac hypertrophy or cardiac failure accompanied by natriuretic peptides upregulation. Chronic treatment of mice with either catecholamines or doxorubicin increased CR9 activity during the progression of cardiac hypertrophy to failure, which is accompanied by proportional increases in Nppb expression. Conversely, for cultured cardiomyocytes, doxorubicin decreased CR9 activity and Nppb expression, while catecholamines increased both. However, exposing cultured cardiomyocytes to mechanical loads, such as mechanical stretch or hydrostatic pressure, upregulate CR9 activity and Nppb expression even in the presence of doxorubicin. Furthermore, the enhancement of CR9 activity and Nppa and Nppb expressions by either catecholamines or mechanical loads can be blunted by suppressing mechanosensing and mechanotransduction pathways, such as muscle LIM protein (MLP) or myosin tension. Finally, the CR9 element showed a more robust and cell-specific response to mechanical loads than the -520-bp BNP promoter. We concluded that the CR9 element is a novel enhancer that responds to mechanical loads by upregulating natriuretic peptides expression in cardiomyocytes.

Topics: Animals; Cardiomegaly; Gene Expression; Heart Failure; LIM Domain Proteins; Mechanotransduction, Cellular; Mice, Transgenic; Muscle Proteins; Myocytes, Cardiac; Natriuretic Peptide, Brain; Natriuretic Peptides; Rats; Transcriptional Activation

Mitochondrial dysfunction has been suggested to be the key factor in the development and progression of cardiac hypertrophy. The onset of mitochondrial dysfunction and the mechanisms underlying the development of cardiac hypertrophy (CH) are incompletely understood. The present study is based on the use of multiple bioinformatics analyses for the organization and analysis of scRNA-seq and microarray datasets from a transverse aortic constriction (TAC) model to examine the potential role of mitochondrial dysfunction in the pathophysiology of CH. The results showed that NADH:ubiquinone oxidoreductase core subunit S1- (Ndufs1-) dependent mitochondrial dysfunction plays a key role in pressure overload-induced CH. Furthermore,

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Biomarkers; Cardiomegaly; Constriction, Pathologic; Down-Regulation; Male; Membrane Potential, Mitochondrial; Mice, Inbred C57BL; Mitochondria, Heart; Myocardium; Myocytes, Cardiac; Myosin Heavy Chains; NADH Dehydrogenase; Natriuretic Peptide, Brain; Pressure; Rats; RNA-Seq; Single-Cell Analysis

We tested the hypothesis that angiotensin II (Ang II)-induced cardiovascular complications are distinguished from what catecholamine-induced by their serum circulating biomarkers in rats. Infusion of Ang II (1.68 mg/kg/day) significantly increased systolic and diastolic blood pressure assessed at week one or later, accompanied by an increase of heart/body weight ratio. Noradrenaline infusion (5.40 mg/kg/day) produced a similar degree of hypertension, but did not increase heart weight. Ang II-, but not noradrenaline-induced hypertension was associated with a drastic upregulation of serum microRNA-30d (miR-30d) by hundreds of times, accompanied by an increase of miR-30d levels in the atrium but not in the ventricle. Ang II, but not noradrenaline, significantly increased mRNA of brain natriuretic peptide (BNP) in the atrium. Studies using rat neonatal cardiomyocytes in vitro demonstrated that BNP caused an increase of miR-30d when applied for 6 h or longer in the culture medium. In vitro application of Ang II increased the cell size, although BNP and miR-30d were unable to mimic the effect of Ang II. We conclude that serum circulating microRNA-30d is a sensitive biomarker for Ang II-induced cardiovascular complications. It is also postulated that Ang II-induced cardiomyocyte hypertrophy could be independent of miR-30d/BNP signaling pathways.

Topics: Angiotensin II; Animals; Biomarkers; Cardiomegaly; Hypertension; MicroRNAs; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats

Although coronavirus disease 2019 (COVID-19) typically presents as a respiratory illness, co-existent cardiovascular symptomatology associated with an elevated serum troponin level has been identified as a risk factor for adverse outcomes. Our study addressed the need to correlate serum cardiovascular biomarkers with tissue pathology based on autopsy.. In 13 patients, we reviewed the clinical history and measurements of serum troponin and other biomarkers and correlated them with autopsy findings.. At autopsy, the 13 COVID-19 patients exhibited evidence of diffuse alveolar damage (DAD) and cardiomegaly (heart weights ranged from 380 to 1170 grams). Of the 13 patients, three had elevated troponin I and evidence of severe coronary artery disease (CAD) (cases 4, 5, and 11), while six had elevated troponin I without evidence of severe CAD (cases 1, 3, 6, 7, 8, and 9), and four had no clinical or pathological evidence of CAD. Of note, cases 7 and 9 had significantly elevated troponin I levels (8.84 ng/mL and 4.94 ng/mL, respectively). Several cases showed focal degenerative change or damage of cardiomyocytes. However, none of the cases had evidence of lymphocytic myocarditis.. Although we observed elevated biomarkers of heart failure in some cases, it was not a consistent finding and did not correlate with evidence of myocarditis. The elevated biomarkers may reflect non-ischemic heart damage as a consequence of COVID-19 infection.

Topics: Autopsy; Biomarkers; Cardiomegaly; Cell Movement; COVID-19; Female; Heart Failure; Humans; Lung; Macrophages, Alveolar; Male; Middle Aged; Myocardium; Natriuretic Peptide, Brain; Organ Size; Peptide Fragments; SARS-CoV-2; Troponin I

Drug-induced long QT syndrome (DI-LQTS) is fatal and known to have a higher incidence in women rather than in men. Multiple risk factors potentiate the incidence of DI-LQTS, but the actual contribution of obesity remains largely unexplored. Correspondingly, the present study is aimed to evaluate the susceptibility of DI-LQTS in WNIN/Ob rat in comparison with its lean counterpart using 3-lead electrocardiography. Four- and eight-month-old female WNIN/Ob and their lean controls were used for the experimentation. Non-invasive blood pressure measurement and total body electric conductivity (TOBEC) analysis were carried out. After the baseline evaluations, animals were anesthetized with Ketamine (50 mg/kg). Haloperidol (12.5 mg/kg single dose) was administered intraperitoneally and ECG was taken at 0, 10, 20, 30, 60 min, and 24 h time points. Myocardial lystes were used to assess the BNP, protein carbonylation, and hydroxyproline content. Adiposity, as assessed by TOBEC, is higher in obese rats with elevated mean arterial blood pressure. Baseline-corrected QT interval (QTc) is significantly higher in the obese rat with a wider QRS complex. The incidence of PVC and VT are more intense in the obese rat. Haloperidol-induced QT prolongation in obese rats was rapidly induced than in lean, which was observed to remain till 24 h in obese groups while normalized in lean controls. Higher levels of BNP, protein carbonylation, hydroxyproline content, and relative heart weights indicated the presence of cardiac hypertrophy. The study provides preliminary evidence that obesity can be a potential risk factor for DI-LQTS with faster onset and longer subsistence.

Topics: Adiposity; Animals; Antipsychotic Agents; Cardiomegaly; Disease Models, Animal; Female; Haloperidol; Heart Rate; Hydroxyproline; Long QT Syndrome; Myocytes, Cardiac; Natriuretic Peptide, Brain; Obesity; Protein Carbonylation; Rats, Inbred Strains; Risk Assessment; Risk Factors; Time Factors

Arbutin is a glycoside reported for its anti-oxidant, anti-inflammatory and anti-tumor properties. However, the cardioprotective effect of Arbutin is not well established. The study aims to understand the effect of arbutin on isoproterenol (ISO)-induced cardiac hypertrophy in mice. The animals were pretreated with Arbutin for a week and ISO was administered for 10 days and then sacrificed. Cardiac injury markers such as creatinine kinase and lactate dehydrogenase concentrations were measured in the serum. The mRNA expression of cardiac hypertrophy markers namely atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were measured using qRT-PCR. The levels of pro-inflammatory cytokines TNF-α and IL-6 were quantified by ELISA in isolated tissues and serum. Other tissue anti-oxidant parameters such as GST, GSH, SOD and TBARS were also measured. TUNEL assay was performed to detect apoptosis. Histology studies were performed using H & E and Masson trichome staining. Immunoblot analysis was used to quantify the protein expression of TLR-4 and NF-κB. ISO-alone-treated group showed significant increase in CK-MB, LDH along with increase in hypertrophic markers ANP and BNP, TNF-α and IL-6 levels in serum and tissues and increased cardiomyocyte apoptosis. Anti-oxidant parameters were significantly decreased and TLR-4 and NF-κB protein expression was found to be upregulated in comparison to the control group. Pretreatment with Arbutin-exhibited significant inhibition of TLR-4/NF-κB pathway with decreased levels of pro-inflammatory cytokines and enhanced myocardial anti-oxidant status. Our study demonstrated that pretreatment with Arbutin exhibits marked protective effects on ISO-induced cardiac hypertrophy in mice. Thus, Arbutin may be used as potential pharmacological interventions in the management of cardiac hypertrophy.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Arbutin; Atrial Natriuretic Factor; Cardiomegaly; Cardiotoxicity; Disease Models, Animal; Interleukin-6; Isoproterenol; Male; Mice, Inbred C57BL; Myocytes, Cardiac; Natriuretic Peptide, Brain; NF-kappa B; Oxidative Stress; Signal Transduction; Toll-Like Receptor 4; Tumor Necrosis Factor-alpha; Ventricular Remodeling

Sirtuin 3 (SIRT3) is a type III histone deacetylase that inhibits cardiac hypertrophy. It is mainly localized in the mitochondria and is thus implicated in mitochondrial metabolism. Recent studies have shown that SIRT3 can also accumulate in the nuclear under stressed conditions, and participated in histone deacetylation of target proteins. Poly [ADP-ribose] polymerase 1 (PARP-1) functions as an important PARP isoform that was involved in cardiac hypertrophy. Our experiments showed that SIRT3 accumulated in the nuclear of cardiomyocytes treated with isoproterenol or SIRT3 overexpression. Moreover, overexpression of SIRT3 by adenovirus inhibited the expression of cardiac hypertrophic genes-ANF and BNP, as well as abrogating PARP-1 activation induced by isoproterenol or phenylephrine. In addition, co-immunoprecipitation experiments revealed that SIRT3 could interact with PARP-1, and overexpression of SIRT3 could decrease the acetylation level of PARP-1. Our results indicate that SIRT3 exerts protective effects against cardiac hypertrophy by reducing the level of acetylation and activity of PARP-1, thus providing novel mechanistic insights into SIRT3-mediated cardiprotective actions.

Topics: Acetylation; Animals; Atrial Natriuretic Factor; Cardiomegaly; Cardiotonic Agents; Cell Line; Isoproterenol; Male; Mitochondria; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phenylephrine; Poly (ADP-Ribose) Polymerase-1; Rats; Rats, Sprague-Dawley; Sirtuin 3

Cardiac hypertrophy is an independent risk factor of many cardiovascular diseases. Several cardiovascular protective properties of

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Collagen Type I; Collagen Type III; Cymbopogon; Fibrosis; Gas Chromatography-Mass Spectrometry; Heart; Injections, Intraperitoneal; Isoproterenol; Male; Myocardium; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Oils, Volatile; Protective Agents; Rats

Pathological cardiac hypertrophy is ultimately accompanied by cardiomyocyte apoptosis. Apoptosis mainly related to calpain-1-mediated apoptotic pathways. Studies had proved that taurine can maintain heart health through antioxidation and antiapoptotic functions, but the effect of taurine on cardiac hypertrophy is still unclear. This study aimed to determine whether taurine could inhibit calpain-1-mediated mitochondria-dependent apoptotic pathways in isoproterenol (ISO)-induced hypertrophic cardiomyocytes. We found that taurine could inhibit the increase in cell surface area and reduce the protein expression levels of the hypertrophic markers atrial natriuretic peptide, brain natriuretic polypeptide, and β-myosin heavy chain. Taurine also reduced ROS, intracellular Ca

Topics: Animals; Apoptosis; Apoptotic Protease-Activating Factor 1; Atrial Natriuretic Factor; bcl-2-Associated X Protein; Calcium; Calcium-Binding Proteins; Calpain; Cardiomegaly; Caspase 3; Caspase 9; Cell Line; Cytochromes c; Isoproterenol; Membrane Potential, Mitochondrial; Mitochondria; Myocytes, Cardiac; Natriuretic Peptide, Brain; Natriuretic Peptides; Oxidative Stress; Proto-Oncogene Proteins c-bcl-2; Rats; Taurine; Ventricular Myosins

This study aimed to explore the role of miR-130a-3p in cardiomyocyte hypertrophy and its underlying mechanisms. Pressure-overload induced myocardial hypertrophy mice model was constructed by thoracic aortic constriction (TAC).. 本研究旨在探索 miR-130a-3p 对心肌细胞肥大的作用及其可能机制。通过胸主动脉缩窄法（TAC）构建压力超负荷所致心肌肥厚小鼠模型。使用去甲肾上腺素（NE）刺激 SD 乳鼠原代心肌细胞（NRCMs）及 H9c2 大鼠心肌细胞系，诱导这两种心肌细胞发生肥大表型转变。检测 miR-130a-3p 的表达变化，并进一步探索其对心肌细胞肥大是否有调控作用。结果表明，miR-130a-3p 在肥厚心肌组织、肥大 NRCMs 及 H9c2 细胞中的表达均明显降低。给予 miR-130a-3p mimics 使其过表达后，H9c2 细胞中肥大标志基因心房利钠肽（ANP）、脑利钠肽（BNP）和肌球蛋白重链 β（β-MHC）的表达较对照组（mimics N.C.+NE 组）明显下调，且细胞面积明显减小。而给予 miR-130a-3p inhibitor 抑制其表达后，肥大心肌细胞中 ANP、BNP、β-MHC 的表达进一步上升，且细胞面积进一步增加。Western blot 检测发现，过表达 miR-130a-3p 后心肌细胞中磷酸化 Akt 和磷酸化 mTOR 的表达水平下调。以上结果提示，miR-130a-3p mimics 可缓解心肌细胞肥大的程度；其 inhibitor 则可使心肌细胞肥大进一步加剧。过表达 miR-130a-3p 可能通过影响 Akt 通路来缓解 H9c2 心肌细胞肥大的程度。.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Mice; MicroRNAs; Myocardium; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Nonmuscle Myosin Type IIB; Proto-Oncogene Proteins c-akt; Rats

Cardiac hypertrophy causes heart failure and is associated with hyperglycemia in patients with diabetes mellitus. Mibefradil, which acts as a T-type calcium channel blocker, exerts beneficial effects in patients with heart failure. In this study, we explored the effects and mechanism of mibefradil on high-glucose-induced cardiac hypertrophy in H9c2 cells. H9c2 cells were incubated in a high-glucose medium and then treated with different concentrations of mibefradil in the presence or absence of the Akt inhibitor MK2206 or mTOR inhibitor rapamycin. Cell size was evaluated through immunofluorescence, and mRNA expression of cardiac hypertrophy markers (atrial natriuretic peptide, brain natriuretic peptide, and β-myosin heavy chain) was assessed by using quantitative real-time polymerase chain reaction. Changes in the expression of p-PI3K, p-Akt, and p-mTOR were evaluated using Western blotting, and autophagosome formation was detected using transmission electron microscopy. Our results indicate that mibefradil reduced the size of H9c2 cells, decreased mRNA expression of atrial natriuretic peptide, brain natriuretic peptide, and β-myosin heavy chain, and decreased the level of autophagic flux. However, MK2206 and rapamycin induced autophagy and reversed the effects of mibefradil on high-glucose-induced H9c2 cells. In conclusion, mibefradil ameliorated high-glucose-induced cardiac hypertrophy by activating the PI3K/Akt/mTOR pathway and inhibiting excessive autophagy. Our study shows that mibefradil can be used therapeutically to ameliorate cardiac hypertrophy in patients with diabetes mellitus.

Topics: Animals; Atrial Natriuretic Factor; Autophagy; Calcium Channel Blockers; Cardiomegaly; Cell Line; Cell Size; Glucose; Mibefradil; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Phosphatidylinositol 3-Kinase; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Signal Transduction; TOR Serine-Threonine Kinases

The aim of the present study was to examine the role of sirtuin 3 (Sirt3)‑autophagy in regulating myocardial energy metabolism and inhibiting myocardial hypertrophy in angiotensin (Ang) II‑induced myocardial cell hypertrophy. The primary cultured myocardial cells of neonatal Sprague Dawley rats were used to construct a myocardial hypertrophy model induced with Ang II. Following the activation of Sirt3 by resveratrol (Res), Sirt3 was silenced using small interfering (si)RNA‑Sirt3, and the morphology of the myocardial cells was observed under an optical microscope. Reverse transcription‑polymerase chain reaction was used to detect the mRNA expression of the following myocardial hypertrophy markers; atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), Sirt3, medium‑chain acyl‑CoA dehydrogenase (MCAD) and pyruvate kinase (PK). Western blot analysis was used to detect the protein expression of Sirt3, light chain 3 (LC3) and Beclin1. Ang II may inhibit the protein expression of Sirt3, LC3 and Beclin1. Res, an agonist of Sirt3, may promote the protein expression of Sirt3, LC3 and Beclin1. Res inhibited the mRNA expression of ANP and BNP, and reversed the Ang II‑induced myocardial cell hypertrophy. The addition of siRNA‑Sirt3 decreased the protein expression of Sirt3, LC3 and Beclin1, increased the mRNA expression of ANP and BNP, and weakened the inhibitory effect of Res on myocardial cell hypertrophy. Res promoted the mRNA expression of MCAD, inhibited the mRNA expression of PK, and reversed the influence of Ang II on myocardial energy metabolism. siRNA‑Sirt3 intervention significantly decreased the effect of Res in eliminating abnormal myocardial energy metabolism. In conclusion, Sirt3 may inhibit Ang II‑induced myocardial hypertrophy and reverse the Ang II‑caused abnormal myocardial energy metabolism through activation of autophagy.

Topics: Acyl-CoA Dehydrogenase; Angiotensin II; Animals; Animals, Newborn; Atrial Natriuretic Factor; Autophagy; Beclin-1; Cardiomegaly; Cells, Cultured; Energy Metabolism; Female; Gene Silencing; Male; Microtubule-Associated Proteins; Myocytes, Cardiac; Natriuretic Peptide, Brain; Pyruvate Kinase; Rats, Sprague-Dawley; Resveratrol; Sirtuins

Cardiomegaly on chest radiographs (CXR) in pediatric patients leads to multiple tests. We aimed to determine the positive predictive value (PPV) of cardiomegaly on CXR in predicting subsequent heart disease and to assess the utility of obtaining a B-type Natriuretic Peptide level (BNP) and/or electrocardiogram (EKG) in such patients. We hypothesized that an echocardiogram may not be appropriate in all cases of cardiomegaly on CXR, particularly in a patient with a normal EKG and BNP level.. We performed a retrospective cohort study of pediatric patients with cardiomegaly on their initial CXR between January 2015-December 2017. Patients without a subsequent echocardiogram or known congenital heart disease were excluded. A patient was deemed to have heart disease if they had structural abnormalities, functional abnormalities or a pericardial effusion on echocardiogram. The PPV of CXR and the PPV/NPV of the other tests (EKG, BNP) were calculated using contingency tables.. Four hundred and eighty nine patients met inclusion criteria. The PPV of cardiomegaly on CXR alone without any other diagnostic testing in predicting subsequent heart disease was 15%. The PPV increased if there was either an abnormal EKG or a BNP >100 pg/ml and further increased if both of these were present. The PPV values were higher in patients <1 year of age.. Cardiomegaly on CXR can often predict the presence of heart disease, particularly in infants. Further testing with EKG and BNP can better predict who may have heart disease, but it may not eliminate the need for echocardiography.

Topics: Cardiomegaly; Child; Child, Preschool; Cohort Studies; Electrocardiography; Female; Heart Diseases; Humans; Infant; Infant, Newborn; Male; Natriuretic Peptide, Brain; Predictive Value of Tests; Radiography, Thoracic; Retrospective Studies

Preeclampsia and fetal growth restriction share some pathophysiologic features and are both associated with placental insufficiency. Fetal cardiac remodeling has been described extensively in fetal growth restriction, whereas little is known about preeclampsia with a normally grown fetus.. To describe fetal cardiac structure and function in pregnancies complicated by preeclampsia and/or fetal growth restriction as compared with uncomplicated pregnancies.. This was a prospective, observational study including pregnancies complicated by normotensive fetal growth restriction (n=36), preeclampsia with a normally grown fetus (n=35), preeclampsia with fetal growth restriction (preeclampsia with a normally grown fetus-fetal growth restriction, n=42), and 111 uncomplicated pregnancies matched by gestational age at ultrasound. Fetal echocardiography was performed at diagnosis for cases and recruitment for uncomplicated pregnancies. Cord blood concentrations of B-type natriuretic peptide and troponin I were measured at delivery. Univariate and multiple regression analysis were conducted.. Pregnancies complicated by preeclampsia and/or fetal growth restriction showed similar patterns of fetal cardiac remodeling with larger hearts (cardiothoracic ratio, median [interquartile range]: uncomplicated pregnancies 0.27 [0.23-0.29], fetal growth restriction 0.31 [0.26-0.34], preeclampsia with a normally grown fetus 0.31 [0.29-0.33), and preeclampsia with fetal growth restriction 0.28 [0.26-0.33]; P<.001) and more spherical right ventricles (right ventricular sphericity index: uncomplicated pregnancies 1.42 [1.25-1.72], fetal growth restriction 1.29 [1.22-1.72], preeclampsia with a normally grown fetus 1.30 [1.33-1.51], and preeclampsia with fetal growth restriction 1.35 [1.27-1.46]; P=.04) and hypertrophic ventricles (relative wall thickness: uncomplicated pregnancies 0.55 [0.48-0.61], fetal growth restriction 0.67 [0.58-0.8], preeclampsia with a normally grown fetus 0.68 [0.61-0.76], and preeclampsia with fetal growth restriction 0.66 [0.58-0.77]; P<.001). Signs of myocardial dysfunction also were observed, with increased myocardial performance index (uncomplicated pregnancies 0.78 z scores [0.32-1.41], fetal growth restriction 1.48 [0.97-2.08], preeclampsia with a normally grown fetus 1.15 [0.75-2.17], and preeclampsia with fetal growth restriction 0.45 [0.54-1.94]; P<.001) and greater cord blood B-type natriuretic peptide (uncomplicated pregnancies 14.2 [8.4-30.9] pg/mL, fetal growth restriction 20.8 [13.1-33.5] pg/mL, preeclampsia with a normally grown fetus 31.8 [16.4-45.8] pg/mL and preeclampsia with fetal growth restriction 37.9 [15.7-105.4] pg/mL; P<.001) and troponin I as compared with uncomplicated pregnancies.. Fetuses of preeclamptic mothers, independently of their growth patterns, presented cardiovascular remodeling and dysfunction in a similar fashion to what has been previously described for fetal growth restriction. Future research is warranted to better elucidate the mechanism(s) underlying fetal cardiac adaptation in these conditions.

Topics: Adult; Cardiomegaly; Echocardiography; Female; Fetal Blood; Fetal Growth Retardation; Fetal Heart; Gestational Age; Humans; Natriuretic Peptide, Brain; Pre-Eclampsia; Pregnancy; Pregnancy Trimester, Third; Prospective Studies; Spain; Troponin I; Ventricular Dysfunction; Ventricular Remodeling

Long-term high salt intake leads to cardiac hypertrophy, but the mechanism remains elusive. Transient receptor potential channel, canonical 3(TRPC3), located in mitochondria, regulates mitochondrial calcium and reactive oxygen species(ROS) production. Herein, we investigated whether TRPC3 participates in high salt-induced cardiac hypertrophy by impairing cardiac mitochondrial function. High salt treatment increased the expression of mitochondrial TRPC3 in cardiomyocytes, accompanied by enhanced mitochondrial calcium uptake and elevated ROS production. Inhibition of TRPC3 significantly reduced high salt-induced ROS generation, promoted ATP production by stimulating oxidative phosphorylation, and increased enzyme activity in mitochondria in cardiomyocytes. Additionally, TRPC3 deficiency inhibited high salt-induced cardiac hypertrophy in vivo. A long-term high salt diet increased cardiac mitochondrial TRPC3 expression, elevated expression of cardiac hypertrophic markers atrial natriuretic peptide (ANP),brain natriuretic peptide (BNP) and β-myosin heavy chain (β-MHC) and decreased ATP production and mitochondrial complex I and II enzyme activity in a TRPC3-dependent manner. TRPC3 deficiency antagonises high salt diet-mediated cardiac hypertrophy by ameliorating TRPC3-mediated cardiac mitochondrial dysfunction. TRPC3 may therefore represent a novel target for preventing high salt-induced cardiac damage.

Topics: Adenosine Triphosphate; Animals; Atrial Natriuretic Factor; Calcium; Cardiomegaly; Cell Line; Electron Transport Complex I; Electron Transport Complex II; Mice, Knockout; Mitochondria; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats; Reactive Oxygen Species; Sodium Chloride, Dietary; TRPC Cation Channels

Isosteviol sodium (STVNa), which is a derivate of the natural sweet‑tasting glycoside stevioside, has recently been developed and it has been determined that this compound exhibits neuro‑ and cardio‑protective properties. In the current study, whether STVNa interferes with the development of cardiac hypertrophy, which is induced by isoprenaline (Iso), was investigated in an experimental rat model. Rats were treated with a vehicle (0.9% NaCl; control), isoprenaline (Iso; 5 mg/kg) or Iso (5 mg/kg) with STVNa (4 mg/kg; Iso + STVNa). Cardiomyocytes were isolated using enzymatic dissociation and were treated with 5 µM Iso for 24 h and co‑treated with 5 µM STVNa. Brain natriuretic peptide (BNP) mRNA expression was determined using PCR analysis. Cell surface area, intracellular reactive oxygen species (ROS), mitochondrial transmembrane potential (ΔΨm), cytoplasmic Ca2+ and Ca2+ and contractile function were examined using a laser scanning confocal microscope. The current study demonstrated that STVNa inhibited Iso‑induced cardiac hypertrophy by inhibiting cardiomyocyte size. STVNa significantly reduced cell surface area and decreased BNP mRNA expression in ventricular cardiomyocyte Iso‑induced hypertrophy. STVNa was also revealed to restore ΔΨm and reduce ROS generation and intracellular Ca2+ concentration when compared with the Iso‑treated group. Additionally, STVNa preserved Ca2+ transients in hypertrophic cardiomyocytes. In conclusion, the present study demonstrated that STVNa protects against Iso‑induced myocardial hypertrophy by reducing oxidative stress, restoring ΔΨm and maintaining Ca2+ homeostasis.

Topics: Animals; Apoptosis; Calcium; Cardiomegaly; Diterpenes, Kaurane; Isoproterenol; Male; Membrane Potential, Mitochondrial; Myocytes, Cardiac; Natriuretic Peptide, Brain; Neuroprotective Agents; Oxidative Stress; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; RNA, Messenger; Signal Transduction

To investigate the effect of Yiqi Wenyang (YQWY) decoction on reversing cardiac hypertrophy induced by the transverse aortic constriction (TAC). Wistar rats aged 7-8 weeks were subjected to TAC surgery and then randomly divided into 4 groups (n = 5/group): Sham group, TAC group, low-dose group and high dose group. After 16-week intragastric administration of YQWY decoction, the effect of YQWY decoction on alleviating cardiomyocyte hypertrophy was examined by transthoracic echocardiography (TTE), hematoxylin/eosin (HE), wheat germ agglutinin (WGA) staining, enzyme linked immunosorbent assay (ELISA), Western blot (WB), immunohistochemistry (IHC) and immunofluorescence (IF), respectively. The results showed significant differences in left ventricle volume-diastole/systole (LV Vol d/s), N-terminal pro-B-type brain natriuretic peptide (NT-proBNP) (P < 0.01), Ejection Fraction (EF), LV mass and fractional shortening (FS) (P < 0.05) between YQWY-treated group and TAC group. HE and WGA staining showed that treatment with YQWY decoction dramatically prevented TAC-induced cardiomycyte hypertrophy. Moreover, the results of WB, IHC and IF indicated that administration of YQWY could suppress the expressions of cardiac hypertrophic markers, which included the atrial natriuretic peptide (ANP), BNP and myosin heavy chain 7 (MYH7) (P < 0.05) and inhibit phosphorylation of GATA binding protein 4 (P-GATA4) (P < 0.05), phosphorylation of extracellular signal-regulated kinase (P-ERK) (P < 0.05), phosphorylation of P38 mitogen activated protein kinase (P-P38) (P < 0.05) and phosphorylation of c-Jun N-terminal kinase (P-JNK) (P < 0.05). Thus, we concluded that YQWY decoction suppressed cardiomyocyte hypertrophy and reversed the impaired heart function, and the curative effects of YQWY decoction were associated with the decreased phosphorylation of GATA4 and mitogen activated protein kinases (MAPKs), as well as the reduced expression of the downstream targets of GATA4, including ANP, BNP, and MYH7.

Topics: Animals; Aorta; Cardiomegaly; Drugs, Chinese Herbal; GATA4 Transcription Factor; Humans; Male; Mitogen-Activated Protein Kinases; Myosin Heavy Chains; Natriuretic Peptide, Brain; Peptide Fragments; Phosphorylation; Rats; Rats, Wistar

Cardiac hypertrophy is a risk factor which can intrigue heart failure. In the present study, we explored whether AdipoRon attenuates isoprenaline (ISO) or l-thyroxine-induced cardiac hypertrophy in Sprague-Dawley (SD) rats and whether the anti-hypertrophy effect is mediated by AMPK-related pathway. Here, cardiac hypertrophy was induced by injection of l-thyroxine or ISO in SD rats. In the treatment group, AdipoRon was co-administered. We examined the effects of AdipoRon on cardiac hypertrophy and hypertrophy signaling pathway. The weight of SD rats was recorded every day. Rats were killed for collection of blood and heart under anesthesia. The left heart weight and heart weight were weighed. Paraffin-embedded heart tissue regions (4 μm) were stained with hematoxylin and eosin or Masson to detect left heart hypertrophy and myocardial fibrosis. The serum BNP levels were determined by using an enzyme-linked immunosorbent assay. The mRNA levels of ANP, BNP, PGC-1α, and ERRα were evaluated by real-time PCR analysis. The protein expression levels of PGC-1α, ERRα, and pAMPK/AMPK were determined by western blot analysis. The results showed that AdipoRon significantly reversed heart weight (HW)/body weight (BW) ratio, left ventricular (LV)/BW ratio, serum BNP level and the mRNA level of ANP and BNP induced by ISO or l-thyroxine. ISO or l-thyroxine reduced both the mRNA level and protein level of ERRα and PGC-1α, and also reduced the protein level of pAMPK/AMPK. However, AdipoRon reversed ISO or l-thyroxine-induced changes of pAMPK/AMPK, ERRα, and PGC-1α. Our data indicated that the effects of AdipoRon are mediated partly by activating AMPK-related pathway, and AdipoRon plays a potential role in the prevention of cardiac hypertrophy.

Topics: AMP-Activated Protein Kinases; Animals; Atrial Natriuretic Factor; Body Weight; Cardiomegaly; Gene Expression; Isoproterenol; Male; Natriuretic Peptide, Brain; Organ Size; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Piperidines; Rats, Sprague-Dawley; Signal Transduction; Thyroxine

The antihypertrophic effect of nebivolol over cardioselective beta-blockers (β-blockers) is attributed to the activation of cardiac nitric oxide signaling. However, the precise role of nebivolol on hypertrophied cardiomyocytes remains unclear. In the current study, in vitro cardiomyocyte hypertrophy model was induced with isoprenaline (10 μM), angiotensin II (1 μM), and phenylephrine (20 μM) in neonatal cardiomyocytes isolated from 0- to 2-day-old Sprague-Dawley rats. In addition to hypertrophic agents, cardiomyocytes were treated with nebivolol (1 μM), metoprolol (10 μM), N(ω)-nitro-L-arginine methyl ester (L-NAME) (100 μM), KT5823 (1 μM), DETA-NONOate (1-10 μM), and BAY412272 (10 μM). After 24 hours of treatment, cardiomyocyte size and transcriptional changes in cardiac hypertrophy markers were evaluated. Cardiomyocyte size increased equally in response to all hypertrophic agents. Nebivolol reduced the enhancement in cell size in response to both isoprenaline and angiotensin II; metoprolol did not. The antihypertrophic effect of nebivolol was prevented with L-NAME blockage indicating the role of NOS signaling on cardiomyocyte hypertrophy. The increased mRNA levels of atrial natriuretic peptide induced by isoprenaline decreased with nebivolol, but both β-blockers reduced the angiotensin II-induced increase in atrial natriuretic peptide expression. Combined, these results reveal that by activating NOS signaling, nebivolol exerts antihypertrophic effects on neonatal cardiomyocytes independent from the action mechanism of hypertrophic stimulus.

Topics: Adrenergic beta-1 Receptor Antagonists; Animals; Animals, Newborn; Atrial Natriuretic Factor; Cardiomegaly; Cell Size; Cells, Cultured; Cyclic GMP-Dependent Protein Kinases; Gene Expression Regulation; Myocytes, Cardiac; Natriuretic Peptide, Brain; Nebivolol; Nitric Oxide; Nitric Oxide Synthase; Rats, Sprague-Dawley; Signal Transduction

Cardiac hypertrophy is a myocardial enlargement due to overload pressure, and the primary cause of heart failure. We investigated the function of miR-375-3p in cardiac hypertrophy and its regulating mechanisms. miR-375-3p was upregulated in hearts of the transverse aortic constriction rat model and angiotensin II (Ang II)-induced primary cardiomyocyte hypertrophy model; the opposite was observed for lactate dehydrogenase B (LDHB) protein expression. miR-375-3p knockdown reduced the surface area of primary cardiomyocytes increased by Ang II treatment and decreased the B-natriuretic peptide (BNP) and β-myosin heavy chain (β-MHC) messenger RNA (mRNA) and protein levels. miR-375-3p was also observed to directly target LDHB. LDHB knockdown increased the surface area of Ang II-treated primary cardiomyocytes and increased the BNP and β-MHC mRNA and protein levels. LDHB knockdown attenuated the effects of miR-375-3p on the surface area of primary cardiomyocytes and BNP and β-MHC levels. Therefore, miR-375-3p inhibitor suppresses Ang II-induced cardiomyocyte hypertrophy by promoting LDHB expression.

Topics: Angiotensin II; Animals; Aorta; Cardiomegaly; Disease Models, Animal; Gene Expression Regulation; Gene Knockdown Techniques; Heart Failure; Humans; Isoenzymes; L-Lactate Dehydrogenase; MicroRNAs; Myocardium; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Primary Cell Culture; Rats; Signal Transduction

Cardiac hypertrophy is widely diagnosed in clinical cardiac disorders. The pathophysiology of hypertrophy is complex and multifactorial, a series of molecular and cellular changes are participated, such as activation of different signaling pathways, a switch of fetal gene program in the myocardium, and apoptosis. Some biomarkers have been applied to assess cardiac hypertrophy including atrial natriuretic peptides (ANP), brain/B-type natriuretic peptides (BNP), and α- or β- Myosin Heavy Chain (MHC) in addition to others. Recently, ubiquitin-protein ligase E3A (UBE3A) has been observed to increase in cardiac hypertrophy. Therefore, UBE3A as a new biomarker seems valuable in the clinic. The cardiac hypertrophy is induced in rat-derived heart cell line H9c2 cells by potassium bromate (KBrO3), high glucose (HG), or isoproterenol (Iso), respectively. As an oxidizing agent, KBrO3 increased cell size at concentrations less than 250 μM. Similarly, HG and Iso also induced cardiac hypertrophy in H9c2 cells. Interestingly, each kind of the cell models promoted the gene expression of the well-known biomarkers of cardiac hypertrophy including atrial natriuretic peptides (ANP) and brain/B-type natriuretic peptides (BNP). Additionally, UBE3A is also raised with the signals involved in cardiac hypertrophy such as calcineurin and nuclear factor of activated T-cells (NFAT) determined using Western blots. KBrO3 increased the protein levels of these signals and the specific inhibitor, such as cyclosporine A and tacrolimus, attenuated the signaling in H9c2 cells at concentrations sufficient to inhibit calcineurin in addition to the reduction of mRNA levels of UBE3A, similar to ANP or BNP. Moreover, HG or Iso also significantly increased protein levels of UBE3A in H9c2 cells. Taken together, we provided a new view that UBE3A is markedly raised in cardiac hypertrophy using various cell models, mainly through the activation of the calcineurin/NFAT signaling pathway in H9c2 cells. Therefore, UBE3A could be developed as a new biomarker in the diagnosis of cardiac hypertrophy.

Topics: Animals; Atrial Natriuretic Factor; Biomarkers; Calcineurin; Cardiomegaly; Cell Line; Humans; Models, Biological; Myocytes, Cardiac; Natriuretic Peptide, Brain; NFATC Transcription Factors; Rats; Ubiquitin-Protein Ligases

Angiotensin II (AII) has been well known to induce cardiomyocyte hypertrophy. Epigallocatechin-3-gallate (EGCG) is the main active component of green tea and it has been shown to exhibit strong cardioprotective potential, although the underlying molecular mechanisms remain unclear. In this study, we investigated the role and mechanism of EGCG in preventing AII-induced cardiomyocyte hypertrophy using rat H9c2 cardiomyocytes cells. Reactive oxygen species assay, cell size, and mRNA expression of cardiac hypertrophy markers ANP and BNP were assessed in response to AII treatment. In addition, expression of proteins involved in Hippo signaling pathway were determined by western blot analysis. We found that AII treatment resulted in significant upregulation of ANP and BNP expression levels and increase in H9c2 cell size, which were markedly attenuated by EGCG treatment. Furthermore, our results suggested that EGCG inhibited AII-induced cardiac hypertrophy via regulating the Hippo signaling pathway. Therefore, EGCG may be an effective agent for preventing cardiac hypertrophy.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Cardiomegaly; Catechin; Cell Line; Gene Expression Regulation; Molecular Structure; Myocytes, Cardiac; Natriuretic Peptide, Brain; Protein Serine-Threonine Kinases; Rats; Reactive Oxygen Species; Signal Transduction

Chronic kidney disease (CKD) promotes hypertrophy and fibrosis in heart, and increases the risk of cardiovascular mortality. Ferric citrate is a dietary phosphate binder used to control hyperphosphatemia in CKD patients. It has been shown to raise iron stores, improve anemia and secondary hyperparathyroidism, and decrease vascular calcification in CKD patients. The present study was done to explore the effects and mechanism of actions of ferric citrate on cardiac hypertrophy and fibrosis.. Male SD rats were randomized to CKD (5/6 nephrectomized) and sham-operated control groups. CKD rats were fed regular diet or a diet containing 4% ferric citrate. After 8 weeks, hemoglobin, renal function and cardiovascular endpoints including blood pressure, heart/body weight ratio, serum N-terminal prohormone of brain natriuretic peptide (NT-proBNP), cardiac histology and markers of hypertrophy, fibrosis and inflammation were assessed.. Compared to the controls, untreated CKD group exhibited hypertension, elevated serum urea, creatinine, phosphate, and NT-proBNP concentrations, anemia, cardiomegaly ,cardiac hypertrophy and fibrosis. Treatment with ferric citrate significantly increased hemoglobin and serum iron concentrations, reduced serum phosphate and NT-proBNP levels and ameliorated hypertension, heart/body weight ratio, cardiac hypertrophy, fibrosis and inflammation. In addition, ferric citrate administration reduced the size of cardiomyocytes and expressions of myocardin, transforming growth factor-β, interleukin-6 and monocyte chemotactic protein 1.. Treatment with ferric citrate attenuated renal failure and cardiovascular abnormalities including myocardial hypertrophy and fibrosis in CKD rats.

Topics: Animals; Biomarkers; Cardiomegaly; Ferric Compounds; Fibrosis; Iron; Male; Natriuretic Peptide, Brain; Peptide Fragments; Phosphates; Random Allocation; Rats; Rats, Sprague-Dawley; Renal Insufficiency, Chronic

Adaptive immunity is crucial in cardiovascular and renal inflammation/fibrosis upon hyperactivation of mineralocorticoid receptor. We have previously demonstrated that dendritic cells can respond to mineralocorticoid receptor activation, and the neutrophil gelatinase-associated lipocalin (NGAL) in dendritic cells is highly increased during aldosterone (Aldo)/mineralocorticoid receptor-dependent cardiovascular damage. However, the interrelationship among dendritic cells, target organs inflammation/fibrosis induced by mineralocorticoid receptor, and NGAL-dependence remains unknown.. We studied the role of dendritic cells in mineralocorticoid receptor-dependent tissue remodeling and whether NGAL can modulate the inflammatory response of dendritic cells after mineralocorticoid receptor activation.. Cardiovascular and renal remodeling induced by Aldo and high-salt diet [nephrectomy-Aldo-salt (NAS) model] were analyzed in CD11c.DOG mice, a model which allows dendritic cells ablation by using diphtheria toxin. In addition, in-vitro studies in NGAL-knock out dendritic cells were performed to determine the immunomodulatory role of NGAL upon Aldo treatment.. The ablation of dendritic cells prevented the development of cardiac hypertrophy, perivascular fibrosis, and the overexpression of NGAL, brain natriuretic peptide, and two profibrotic factors induced by NAS: collagen 1A1 and connective tissue growth factor. We determined that dendritic cells were not required to prevent renal hypertrophy/fibrosis induced by NAS. Between different immune cells analyzed, we observed that NGAL abundance was higher in antigen-presenting cells, while in-vitro studies showed that mineralocorticoid receptor stimulation in dendritic cells favored NGAL and IL-23 expression (p19 and p40 subunits), which are involved in the development of fibrosis and the Th17-driven response, respectively.. NGAL produced by dendritic cells may play a pivotal role in the activation of adaptive immunity that leads to cardiovascular fibrosis during mineralocorticoids excess.

Topics: Aldosterone; Animals; Cardiomegaly; Cardiovascular System; CD11 Antigens; Coculture Techniques; Dendritic Cells; Female; Fibrosis; Hyperaldosteronism; Inflammation; Interleukin-23 Subunit p19; Kidney; Lipocalin-2; Lymphocyte Activation; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Natriuretic Peptide, Brain; Receptors, Mineralocorticoid; Sodium Chloride, Dietary; T-Lymphocytes

Pathological cardiac hypertrophy eventually leads to heart failure without adequate treatment. The immunoproteasome is an inducible form of the proteasome that is intimately involved in inflammatory diseases. Here, we found that the expression and activity of immunoproteasome catalytic subunit β5i were significantly up-regulated in angiotensin II (Ang II)-treated cardiomyocytes and in the hypertrophic hearts. Knockout of β5i in cardiomyocytes and mice markedly attenuated the hypertrophic response, and this effect was aggravated by β5i overexpression in cardiomyocytes and transgenic mice. Mechanistically, β5i interacted with and promoted ATG5 degradation thereby leading to inhibition of autophagy and cardiac hypertrophy. Further, knockdown of ATG5 or inhibition of autophagy reversed the β5i knockout-mediated reduction of cardiomyocyte hypertrophy induced by Ang II or pressure overload. Together, this study identifies a novel role for β5i in the regulation of cardiac hypertrophy. The inhibition of β5i activity may provide a new therapeutic approach for hypertrophic diseases.

Topics: Aged; Aged, 80 and over; Angiotensin II; Animals; Autophagy; Autophagy-Related Protein 5; Cardiomegaly; Case-Control Studies; Catalytic Domain; Female; Heart Failure; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Middle Aged; Myocardium; Natriuretic Peptide, Brain; Proteasome Endopeptidase Complex; Rats; RNA Interference; RNA, Small Interfering; Up-Regulation

This paper was aimed to investigate the inhibitory effect of aconitine(AC) on angiotensin Ⅱ(Ang Ⅱ)-induced H9 c2 cell hypertrophy and explore its mechanism of action. The model of hypertrophy was induced by Ang Ⅱ(1×10-6 mol·L-1),and cardiomyocytes were incubated with different concentrations of AC. Western blot was used to quantify the protein expression levels of atrial natriuretic peptide(ANP),brain natriuretic peptide(BNP),β-myosin heavy chain(β-MHC),and α-smooth muscle actin(α-SMA). Real-time quantitative PCR(qRT-PCR) was used to quantify the mRNA expression levels of cardiac hypertrophic markers ANP,BNP and β-MHC. In addition,the fluorescence intensity of the F-actin marker,an important component of myofibrils,was detected by using laser confocal microscope. AC could significantly reverse the increase of total protein content in H9 c2 cells induced by Ang Ⅱ; qRT-PCR results showed that AC could significantly inhibit the ANP,BNP and β-MHC mRNA up-regulation induced by AngⅡ. Western blot results showed that AC could significantly inhibit the ANP,BNP and β-MHC protein up-regulation induced by AngⅡ. In addition,F-actin expression induced by Ang Ⅱ could be inhibited by AC,and multiple indicators of cardiomyocyte hypertrophy induced by Ang Ⅱ could be down-regulated,indicating that AC may inhibit cardiac hypertrophy by inhibiting the expression of hypertrophic factors,providing new clues for exploring the cardiovascular protection of AC.

Topics: Aconitine; Actins; Angiotensin II; Atrial Natriuretic Factor; Cardiac Myosins; Cardiomegaly; Cells, Cultured; Humans; Hypertrophy; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain

Topics: Acute Kidney Injury; Animals; Arginine; Cardiomegaly; Disease Models, Animal; Disease Progression; Down-Regulation; Enzyme Activation; Fibrosis; HSP90 Heat-Shock Proteins; Male; Myocardium; Natriuretic Peptide, Brain; Nitric Oxide; Nitric Oxide Synthase Type III; Oxidative Stress; Phosphorylation; Rats, Wistar; Renal Insufficiency, Chronic; Threonine; Time Factors

Stress-induced cardiac hypertrophy leads to heart failure. Our previous studies demonstrate that insulin-like growth factor-II receptor (IGF-IIR) signaling is pivotal to hypertrophy regulation. In this study, we show a novel IGF-IIR alternative spliced transcript, IGF-IIRα (150 kDa) play a key role in high-salt induced hypertrophy mechanisms. Cardiac overexpression of IGF-IIRα and high-salt diet influenced cardiac dysfunction by increasing pathophysiological changes with up-regulation of hypertrophy markers, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). We found that, cardiac hypertrophy under high-salt conditions were amplified in the presence of IGF-IIRα overexpression. Importantly, high-salt induced angiotensin II type I receptor (AT1R) up regulation mediated IGF-IIR expressions via upstream mitogen activated protein kinase (MAPK)/silent mating type information regulation 2 homolog 1 (SIRT1)/heat shock factor 1 (HSF1) pathway. Further, G-coupled receptors (Gαq) activated calcineurin/nuclear factor of activated T-cells, cytoplasmic 3 (NFATc3)/protein kinase C (PKC) signaling was significantly up regulated under high-salt conditions. All these effects were observed to be dramatically over-regulated in IGF-IIRα transgenic rats fed with a high-salt diet. Altogether, from the findings, we demonstrate that IGF-IIRα plays a crucial role during high-salt conditions leading to synergistic cardiac hypertrophy.

Topics: Alternative Splicing; Animals; Atrial Natriuretic Factor; Cardiomegaly; Female; Male; MAP Kinase Signaling System; Natriuretic Peptide, Brain; Organ Specificity; Rats; Rats, Sprague-Dawley; Rats, Transgenic; Receptor, IGF Type 2; Sodium Chloride, Dietary

Topics: Animals; Aspartate Aminotransferases; Atrial Natriuretic Factor; Biomarkers; Bone Morphogenetic Proteins; Cardiomegaly; Creatine Kinase; DNA Methylation; Female; Gene Expression Regulation; Homeobox Protein Nkx-2.5; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; L-Lactate Dehydrogenase; Male; Maternal Exposure; Mice; Natriuretic Peptide, Brain; Nitrogen Dioxide; Pregnancy; Reactive Oxygen Species; Ventricular Myosins

Molecular hydrogen has been shown to have antioxidant effect and have been used to prevent oxidative stress-related diseases. The goal of this study was to explore if hydrogen-rich saline (HRS) plays a cardioprotective effect on abdominal aortic constriction (AAC) induced cardiac hypertrophy in rats. 60adult Sprague-Dawley rats received surgically the AAC for 6-week. After the surgery, the rats were randomly divided into 4 groups (15 for each):1: sham-operated (sham); 2: AAC-model; 3: AAC + Low HRS (LHRS); and 4: AAC + High HRS (HHRS). The rats in sham and AAC-model groups were treated with normal saline intraperitoneally, while rats in LHRS and HHRS groups were intraperitoneally treated with 3 or 6 mL/kg HRS daily, respectively, for 6-week.. The ratios of HW/BW and LVW/BW were shown in an order of Model > LHRS > HHRS > SHAM groups. The cardiac hypertrophy was also manifested with increased expressions of atrial natriuretic peptide (ANP), brain natriuretic peptides (BNP) and fibrosis of cardiac tissues in AAC-model group, which could likewise be restrained in LHRS and HHRS groups. Moreover, the JAK-STAT (Janus Kinase-Signal transducers and activators of transcription) signaling molecule expressions were decreased with HRS treatment.. Our results showed a protective effect of HRS on pressure overload-induced cardiac hypertrophy in rats, which may be associated to a decreasing in JAK-STAT signaling pathway.

Topics: Animals; Aorta, Abdominal; Apoptosis; Arterial Pressure; Atrial Natriuretic Factor; Cardiomegaly; Constriction; Disease Models, Animal; Fibrosis; Fluid Therapy; Hydrogen; Janus Kinases; Male; Myocardium; Natriuretic Peptide, Brain; Rats, Sprague-Dawley; Signal Transduction; Sodium Chloride; STAT Transcription Factors

Activation of stromal interaction molecule 1 (STIM1) and Orai1 participates in the development of cardiac hypertrophy. Store-operated Ca2+ entry-associated regulatory factor (SARAF) is an intrinsic inhibitor of STIM1-Orai1 interaction. Thus, we hypothesized that SARAF could prevent cardiac hypertrophy.. Male C57BL/6 mice, aged 8 weeks, were randomly divided into sham and abdominal aortic constriction surgery groups and were infected with lentiviruses expressing SARAF and GFP (Lenti-SARAF) or GFP alone (Lenti-GFP) via intramyocardial injection. At 4 weeks after aortic constriction, left ventricular structure and function were assessed by echocardiography and hemodynamic assays. The gene and protein expressions of SARAF, STIM1, and Orai1 were measured by quantitative PCR and Western blot, respectively.. Gene and protein expressions of SARAF were significantly decreased, while STIM1 and Orai1 were increased in the heart tissue compared with sham group. Overexpression of SARAF in the heart prevented the upregulation of STIM1 and Orai1, and importantly, attenuated aortic constriction-induced decrease in maximal rate of left ventricular pressure decay and increases in thickness of interventricular septum and left ventricular posterior wall, heart weight/body weight ratio, and size of cardiomyocytes. Blood pressure detected through the carotid artery and left ventricular systolic function were not affected by SARAF overexpression. In addition, overexpression of SARAF also attenuated angiotensin II-induced upregulation of STIM1 and Orai1 and hypertrophy of cultured cardiomyocytes.. Overexpression of SARAF in the heart prevents cardiac hypertrophy, probably through suppressing the upregulation of STIM1/Orai1.

Topics: Angiotensin II; Animals; Aorta, Abdominal; Atrial Natriuretic Factor; Cardiomegaly; Cell Line; Echocardiography; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Myocardium; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; ORAI1 Protein; Pressure; Stromal Interaction Molecule 1; Up-Regulation; Ventricular Function, Left

Cardiomyocyte hypertrophy was induced by isoproterenol (ISO). The cell surface area was measured by image analysis system (Leica). The expression of brain natriuretic peptide(BNP), β-myosin heavy chain(β-MHC), cystathionase (CSE), miRNA-133a, calcineurin (CaN) were detected by qRT-PCR. The protein expressions of CaN、nuclear factors of activated T cells (NFATc4) were detected by Western blot. The concentration of H. ①The level of system of CSE/H

Topics: Animals; Calcineurin; Cardiomegaly; Cells, Cultured; Cystathionine gamma-Lyase; Hydrogen Sulfide; MicroRNAs; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Nerve Tissue Proteins; NFATC Transcription Factors; Rats; Signal Transduction

Dasatinib is a new selective tyrosine kinase inhibitor that targets certain kinases involved in cellular growth and development. This drug belongs to a novel anticancer therapy aiming to increase the survival in patients with imatinib-resistant mutations. However, the dasatinib toxicity was reported as a side effect leading to arrhythmias and/or heart failure. Here, we investigated the possibility of dasatinib-induced toxicity in rat cardiomyocyte H9c2 cells. Our objectives were to investigate the ability of dasatinib to induce expression of cytochrome P450 (CYP1A1, CYP1B1) and cardiac hypertrophy markers (BNP, β-MHC) genes in H9c2 cells. To test this hypothesis, H9c2 cells were incubated with dasatinib at two concentrations (20 and 40 μM). Thereafter, CYP1A1, CYP1B1, BNP, and β-MHC were determined at gene expression level. Our findings showed that dasatinib induces the CYP1A1, CYP1B1, BNP, and β-MHC mRNA. The involvement of AhR/CYP1A1 pathway in dasatinib toxicity was tested by resveratrol (RES), an AhR antagonist. Interestingly, the increase in mRNA of different genes by dasatinib was not affected by RES, which confirms that these effects are not mediated through AhR. In addition, this was accompanied by a significant inhibition of constitutive expression of these genes by RES. The current work provides the first evidence for the ability of dasatinib to induce hypertrophic markers in H9c2 cells through AhR-independent pathway.

Topics: Animals; Antineoplastic Agents; Biomarkers; Cardiomegaly; Cardiotoxicity; Cell Culture Techniques; Cell Line; Cell Survival; Cytochrome P-450 CYP1A1; Cytochrome P-450 CYP1B1; Dasatinib; Gene Expression; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Rats

Nuclear localization leucine-rich-repeat protein 1 (NLRP1) is a cytoplasmic protein, involved in autoimmune diseases, mammalian reproduction, neuronal cell death, and stroke. However, the role of NLRP1 in cardiac hypertrophy remains unclear. We used in vivo and in vitro models to investigate the effects of NLRP1 on cardiac hypertrophy.. We used NLRP1-deficient mice and cultured neonatal rat cardiomyocytes with gain and loss of NLRP1 function. Cardiac hypertrophy was estimated by echocardiographic and hemodynamic measurements, and by pathological and molecular analysis.. Eight weeks after aortic banding (AB), NLRP1 deficiency significantly inhibited aortic banding-induced cardiac hypertrophy, inflammation, and fibrosis. Activation of MAPK, NF-κB, and TGF-β/Smad pathways was reduced in NLRP1-knockout (KO) mice compared with that in wild-type (WT) mice. Consistent with these results, in vitro studies, performed using cultured neonatal mouse cardiomyocytes, confirmed that NLRP1 deficiency protects against cardiomyocyte hypertrophy induced by isoproterenol (PE); this protective activity was associated with the arrest of MAPK and NF-κB signaling.. Our data illustrates that NLRP1 plays a crucial role in the development of cardiac hypertrophy via positive regulation of the MAPK, NF-κB, and TGF-β/Smad signaling pathways.

Topics: Adaptor Proteins, Signal Transducing; Animals; Apoptosis Regulatory Proteins; Atrial Natriuretic Factor; Cardiomegaly; Disease Models, Animal; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitogen-Activated Protein Kinases; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; NF-kappa B; Pressure; Rats; RNA Interference; RNA, Small Interfering; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Signal Transduction

BACKGROUND Dracocephalum heterophyllum Benth flavonoid (DHBF) is a Tibetan and Uighur traditional medicine used to treat various disorders such as hypertension, lung heat, cough, and bronchitis; it has good antioxidant activity. Previous studies have shown that DHBF can reduce blood pressure in renovascular hypertensive rats, improve left ventricular systolic and diastolic function, and improve myocardial contractility. Therefore, we aimed to study the effect of DHBF on cardiomyocyte hypertrophy in cultured cells. MATERIAL AND METHODS Neonatal rat cardiomyocytes were cultured, and hypertrophy was induced by angiotensin II (Ang II), with or without varying concentrations of the DHBF extract. Cell Counting Kit-8 assay was used to assess cell viability, RT-qPCR was used to determine mRNA levels, confocal laser scanning microscopy was used to measure cell surface area and intracellular Ca2+ concentrations ([Ca2+]i), and colorimetric assays were used to assess nitric oxide (NO) levels and nitric oxide synthase (NOS) activity. RESULTS Ang II treatment of cardiomyocytes reduced cell viability to ~75% that of controls. Ang II treatment also increased cell surface area; increased mRNA expression of c-jun, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and β-myosin heavy chain (β-MHC); increased [Ca2+]i; and reduced NOS activity and NO production. DHBF treatment could reverse these effects in a concentration-dependent manner. CONCLUSIONS These results showed that DHBF can ameliorate cardiomyocyte hypertrophy induced by Ang II, as indicated by the downregulation of cardiac hypertrophy genes (ANP, BNP, and β-MHC) and reduction in cell surface area. The mechanism may be related to NO release and [Ca2+]I regulation.

Topics: Angiotensin II; Animals; Animals, Newborn; Atrial Natriuretic Factor; Cardiomegaly; Cardiomyopathy, Hypertrophic; Cells, Cultured; China; Flavonoids; Heart Ventricles; Medicine, Tibetan Traditional; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Primary Cell Culture; Rats; Rats, Sprague-Dawley; Signal Transduction

Cardiac hypertrophy is commonly involved in cardiac injury. Oxidative stress can induce cardiac hypertrophy with apoptosis. Potassium bromate (KBrO3) has been widely used as a food additive due to its oxidizing properties. In the present study, the rat‑derived heart cell line H9c2 was used to investigate the effect of KBrO3 on cell size. KBrO3 increased cell size at concentrations <250 µM, in a dose‑dependent manner. Additionally, KBrO3 also promoted the gene expression of two biomarkers of cardiac hypertrophy, brain/B‑type natriuretic peptides (BNP) and β‑Myosin Heavy Chain (β‑MHC). However, apoptosis remained unobserved in these cells. Moreover, mediation of free radicals was investigated using a fluorescence assay, and it was observed that superoxide and reactive oxygen species (ROS) levels increased with KBrO3. Effects of KBrO3 were significantly reduced by tiron at concentrations sufficient to produce antioxidant‑like action. Additionally, signals involved in cardiac hypertrophy such as calcineurin and nuclear factor of activated T‑cells (NFAT) were also determined using western blot analysis. KBrO3 increased the protein levels of both these molecules which were decreased by tiron in a dose‑dependent manner. Additionally, cyclosporine A attenuated the cardiac hypertrophy induced by KBrO3 in H9c2 cells at concentrations effective to inhibit calcineurin, in addition to reducing mRNA levels of BNP or β‑MHC. Finally, apoptosis was also identified in H9c2 cells incubated with KBrO3 at concentrations >300 µM. Collectively, these results provided a novel perspective that KBrO3 induces cardiac hypertrophy without apoptosis at a low dose through the generation of ROS, activating the calcineurin/NFAT signaling pathway in H9c2 cells. Therefore, at a dose <250 µM, KBrO3 can be applied as an inducer of cardiac hypertrophy without apoptosis in H9c2 cells. KBrO3 can also be developed as a tool to induce cardiac hypertrophy in animals.

Topics: 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; Animals; Apoptosis; Bromates; Calcineurin; Cardiomegaly; Cell Line; Cell Size; Cyclosporine; Gene Expression Regulation; Humans; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Rats; Reactive Oxygen Species; Signal Transduction

Bakuchiol (Bak), a monoterpene phenol isolated from the seeds of Psoralea corylifolia, has been widely used to treat a large variety of diseases in both Indian and Chinese folkloric medicine. However, the effects of Bak on cardiac hypertrophy remain unclear. Therefore, the present study was designed to determine whether Bak could alleviate cardiac hypertrophy. Mice were subjected to aortic banding (AB) to induce cardiac hypertrophy model. Bak of 1 ml/100 g body weight was given by oral gavage once a day from 1 to 8 weeks after surgery. Our data demonstrated for the first time that Bak could attenuate pressure overload-induced cardiac hypertrophy and could attenuate fibrosis and the inflammatory response induced by AB. The results further revealed that the effect of Bak on cardiac hypertrophy was mediated by blocking the activation of the NF-κB signaling pathway.

Topics: Administration, Oral; Angiotensin II; Animals; Aorta; Atrial Natriuretic Factor; Cardiomegaly; Cardiotonic Agents; Collagen; Connective Tissue Growth Factor; Constriction, Pathologic; Gene Expression Regulation; Male; Mice; Mice, Inbred C57BL; Myocytes, Cardiac; Natriuretic Peptide, Brain; NF-kappa B; Phenols; Plant Extracts; Primary Cell Culture; Psoralea; Signal Transduction

Our previous studies have shown that Src homology 2 (SH2) B adaptor protein 1 (SH2B1) plays an important role in cardiac hypertrophy, but the specific mechanism remains to be studied. Through bioinformatics and related research, it is found that miR-14 2-3 p is closely related to SH2B1. Exploring the relationship between miR-14 2-3 p and gene SH2B1 expression is beneficial for the treatment of cardiac hypertrophy. SH2B1 is a key factor regulating energy metabolism, mitochondria are the main organelles of energy metabolism and cardiac hypertrophy are closely related to mitochondrial dysfunction. So it is particularly important to explore the relationship between miR-14 2-3 p and SH2B1 and myocardial mitochondrial function. In this study, we investigated whether overexpression of miR-14 2-3 p can inhibit the expression of gene SH2B1, ameliorate cardiac mitochondrial dysfunction and cardiac hypertrophy.. We first constructed a pressure overload myocardial hypertrophy model by ligation of the abdominal aorta(AB) of rats. After 4 weeks of modeling, echocardiographic examination showed that the heart volume of the model group became larger, and Hematoxylin and Eosin Staining Kit (HE) staining showed that the cross-sectional area of the heart tissue became larger. The expression of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), β-Myosin Heavy Chain (β-MHC) messenger RNA (mRNA) increased by real‑time polymerase chain reaction (PCR), which proved that the model of cardiac hypertrophy was successfully constructed. Then, miR-14 2-3 p agomir was injected into the tail vein of rats 2 weeks and 4 weeks respectively. The expression of miR-4 2-3 p mRNA was increased by PCR, suggesting that the miR-14 2-3 p plasmid was successfully transfected. At 4 weeks of pressure overload myocardial hypertrophy model, echocardiography was used to detect cardiac function. HE staining of heart tissue and the expression of ANP, BNP, β-MHC mRNA were used to detect cardiac hypertrophy. Flow cytometry was used to detect changes in mitochondrial membrane potential. Secondly, we observed the effect of miR-14 2-3 p on cardiomyocyte hypertrophy and mitochondrial function in vitro by culture neonatal rat cardiomyocytes. Afterwards, using angiotensin (Ang)II-, miRNA mimic- and miRNA mimic nc- treated cardiomyocytes for a given time. α-actin staining found that the myocardial cells became larger, The expression of ANP, BNP, β-MHC mRNA increased by PCR, which proved that AngII-induced cardiac hypertrophy was successfully constructed. Then, the mitochondrial density was measured using mitochondrial Mito-Red staining by Confocal microscope, the mitochondrial membrane potential was evaluated using flow cytometry, Mitochondrial respiration oxygen consumption rate (OCR) was measured by a Seahorse Extracellular Flux Analyzer XF96, and the expression levels of miR-14 2-3 p, ANP, BNP, β-MHC mRNA, SH2B1 in the cardiomyocytes of different groups were measured by RT-PCR and Western blotting. Finally, we used luciferase assay and transfected miR-14 2-3 p agomir in rats, transfected miR-14 2-3 p mimic in Cardiomyocytes, it is found that myocardial SH2B1 mRNA and protein expression both were reduced.. When the pressure overload myocardial hypertrophy model was constructed for four weeks, echocardiography revealed that the heart volume, Left ventricular end diastolic diameter(LVIDd), Left ventricular end systolic diameter (LVIDs), Left ventricular posterior wall thickness (LVPWd), Systolic left ventricular posterior wall (LVPWs), Left ventricle (LV) Mass increased, Ejection fraction (EF) % decreased of AB group increased, but transfected with miR-14 2-3 p agomir of AB, these increase was not significant, EF% reduction was not obvious. HE staining showed that the myocardial cross-sectional area of AB group increased significantly, but the miR-14 2-3 p agomir treatment of AB group did not increase significantly. PCR analysis showed that the expression of ANP, BNP,β-MHC mRNA was significantly increased in AB group, but the miR-14 2-3 p agomir treatment of AB group was not significantly increased. Flow cytometry showed that the mitochondrial membrane potential of AB group was significantly reduced, and the miR-14 2-3 p agomir treatment of AB group was not significantly decreased. During AngII-induced cardiomyocyte hypertrophy, ANP, BNP,β-MHC mRNA expression was increased, while these factors was not significantly increased in miR-14 2-3 p mimic treatment group; mitochondrial membrane potential, mitochondrial density and OCR was significantly decreased in AngII treated group, and these were not significantly reduced in miR-14 2-3 p mimic treatment group; CONCLUSIONS: miR-14 2-3 p not only mitigate cardiac hypertrophy by directly inhibit the expression of gene SH2B1, but also can protect mitochondrial function in cardiac hypertrophy of vitro and vivo.

Topics: Angiotensin II; Animals; Apoptosis; Atrial Natriuretic Factor; Cardiomegaly; Carrier Proteins; Cells, Cultured; Heart Failure; Intracellular Signaling Peptides and Proteins; Male; MicroRNAs; Mitochondria, Heart; Myocardium; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley

Growth differentiation factor 11 (GDF11) decreases with age, and increased C-C motif chemokine 11 (CCL11) is involved in aging. However, the effects of GDF11 on Angiotensin II (ANG II)-induced hypertrophic cardiomyopathy and expression of markers for volume overload and hypertrophy such as ANP, BNP and beta-MHC, as well as the relationship between GDF11 and CCL11 in hypertrophic cardiomyopathy are unclear. Therefore, the current study aimed to examine the effects of GDF11 on ANG II-induced hypertrophic cardiomyopathy and expression of ANP, BNP and beta-MHC in mice, and explore possible molecular mechanisms.. Vectors were constructed and viruses were packaged. Mouse cardiomyocytes were treated with ANG II for 24 h. Meanwhile, mouse cardiomyocytes were divided into 4 groups: (1) control; (2) ANG II; (3) ANG II+GDF11; and (4) ANG II+CCL11. Furthermore, mouse cardiomyocytes were treated with GDF11 and CCL11 proteins for 48 h, respectively. The thickness of IVS and LVPS during systole and diastole were measured by cardiac ultrasound in the mouse model of hypertrophic cardiomyopathy. The relative expression of ANP, BNP, beta-MHC, CCL11 and GDF11 in cardiomyocytes or heart tissue of mice was detected by qPCR or Western blot. 3'- UTR luciferase reporter assay was utilized to examine the relationship between GDF11 and the expression of CCL11.. The expression of ANP, BNP, and beta-MHC in mouse cardiomyocytes was significantly increased after the cells were treated with 800 nM ANG II, which was utilized in the following cell experiments. After ANG II treatment, 0.2 ng/ml GDF11 group displayed the highest inhibition of expression of ANP, BNP and beta-MHC in mouse cardiomyocytes, whereas 50 ng/ml CCL11 group displayed the highest stimulation of the expression. GDF11 at 10 ng/ml significantly decreased the expression of CCL11 in mouse cardiomyocytes as compared to the control group. Mice treated with ANG II had increased thickness of IVS and LVPS during both systole and diastole, which was significantly attenuated by GDF11 overexpression. GDF11 overexpression attenuated the increase in expression of ANP, BNP and beta-MHC in the mice model of hypertrophic cardiomyopathy. The relative serum concentration of GDF11 was markedly decreased, and CCL11 was dramatically increased in mice with hypertrophic cardiomyopathy. GDF11 overexpression restored the serum concentration of GDF11 and CCL11 in the mice model of hypertrophic cardiomyopathy. In addition, GDF11 interference group had markedly increased expression of CCL11, whereas GDF11 overexpression group had significantly decreased expression of CCL11 in luciferase reporter assay.. GDF11 attenuated ANG II-induced hypertrophic cardiomyopathy and expression of ANP, BNP and beta-MHC through down-regulating CCL11 in mice.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Bone Morphogenetic Proteins; Cardiomegaly; Chemokine CCL11; Down-Regulation; Growth Differentiation Factors; Mice; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain

Telmisartan, a type of angiotensin II (Ang II) receptor inhibitor, is a common agent used to treat hypertension in the clinic. Hypertension increases cardiac afterload and promotes cardiac hypertrophy. However, the ventricular Ang II receptor may be activated in the absence of hypertension. Therefore, telmisartan may reduce cardiac hypertrophy by indirectly ameliorating hypertensive symptoms and directly inhibiting the cardiac Ang II receptor. Nuclear factor of activated T‑cells (NFAT) contributes to cardiac hypertrophy via nuclear translocation, which induces a cascade of atrial natriuretic peptide (ANP) and brain/B‑type natriuretic peptide (BNP) expression and cardiomyocyte apoptosis. However, NFAT-mediated inhibition of cardiac hypertrophy by telmisartan remains poorly understood. The present study demonstrated that telmisartan suppressed cardiomyocyte hypertrophy in a mouse model of cardiac afterload and in cultured cardiomyocytes by inhibiting NFAT nuclear translocation, as well as by inhibiting ANP and BNP expression and cardiomyocyte apoptosis, in a dose‑dependent manner. The present study provides a novel insight into the potential underlying mechanisms of telmisartan-induced inhibition of cardiomyocyte hypertrophy, which involves inhibition of NFAT activation, nuclear translocation and the ANP/BNP cascade.

Topics: Active Transport, Cell Nucleus; Animals; Apoptosis; Atrial Natriuretic Factor; Benzimidazoles; Benzoates; Cardiomegaly; Cell Nucleus; Male; Mice; Myocytes, Cardiac; Natriuretic Peptide, Brain; NFATC Transcription Factors; Signal Transduction; Telmisartan

Cardiac hypertrophy is a crucial predictor of heart failure and is regulated by microRNAs. MicroRNA-124 (miR-124) is regarded as a prognostic indicator for outcomes after cardiac arrest. However, whether miR-124 participates in cardiac hypertrophy remains unclear. Therefore, our study aimed to determine the role of miR-124 in angiotensin II(AngII)-induced myocardial hypertrophy and the possible mechanism. Primary cultured rat neonatal cardiomyocytes(NCMs) were transfected with miR-124 mimics or inhibitor, followed by AngII stimulation. Quantitative RT-PCR, western blot analysis and determination of cell surface area of NCMs were used to detect the hypertrophic phenotypes. We observed that miR-124 was elevated in AngII-induced hypertrophic cardiomyocytes. Cell surface area of NCMs and mRNA expression of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and β-myosin heavy chain (β-MHC), indicators of myocardial hypertrophy, were higher in NCMs transfected with miR-124 mimics in the presence of AngII. On the contrary, knockdown of miR-124 by its specific inhibitor could restore these courses. Furthermore, downregulation of miR-124 alleviated the increased protein level of endoplasmic reticulum (ER) stress markers 78-kDa glucose-regulated protein (Grp78) and calreticulin(CRT) in AngII-induced NCMs. In conclusion, our study shows that inhibition of miR-124 effectively suppresses AngII-induced myocardial hypertrophy, which is associated with attenuation of ER stress.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Calreticulin; Cardiomegaly; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Gene Expression Regulation; Heat-Shock Proteins; Humans; MicroRNAs; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats; Ventricular Myosins

Nicotinamide phosphoribosyltransferase (Nampt) is involved in the development of cardiac hypertrophy. Transient receptor potential canonical channel 1 (TRPC1) and endoplasmic reticulum stress (ER stress) are regarded as critical pathways in cardiac hypertrophy. Therefore, we hypothesizedthat TRPC1 might be associated with ER stress in Nampt-induced cardiac hypertrophy. CulturedH9c2cardiomyocyteswereexposed to Namptfor different timesand the expression of markers of cardiomyocyte hypertrophy and ER stress, as well as TRPC1 were detected. Moreover, specific TRPC1-shRNA (short hairpin RNA) expressing plasmid was transfected to knockdown TRPC1 expression before Nampt stimulation. Thapsigargin was used as an agonist and pravastatin was employed as an inhibitor of ER stress. The results demonstrated that exposure of H9c2 cells to 100 ng/mL Nampt for 24h, 48h or 72h significantly increased the expression of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), markers of ER stress and TRPC1. The Nampt-induced expression of TRPC1 was attenuated by pre-treatment with pravastatin, whereas promoted by pre-treatment with thapsigargin. Furthermore, transfection of TRPC1-shRNA for 48h partially inhibited Nampt-induced expression of ER stress markers and BNP in H9c2 cells. Our data suggest that TRPC1 might play an important role in cardiomyocyte hypertrophy induced by Namptinan ER stress-dependent way.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Endoplasmic Reticulum Stress; Gene Expression Regulation; Humans; Myocytes, Cardiac; Natriuretic Peptide, Brain; Nicotinamide Phosphoribosyltransferase; Pravastatin; Rats; RNA, Small Interfering; Transfection; TRPC Cation Channels

Previous studies have demonstrated that lercanidipine, a calcium channel blocker, may protect against cardiac hypertrophy; however, the underlying mechanisms remain unclear. In the present study, the effects of lercanidipine on hypertrophy and the mechanisms involved were investigated. Cardiomyocytes isolated from neonatal rats were cultured and treated with angiotensin II (Ang II) in the presence or absence of lercanidipine or tacrolimus (FK506, a calcineurin inhibitor). Reverse transcription‑quantitative polymerase chain reaction was used to assess the mRNA expression of genes of interest, whereas the protein expression of calcium‑dependent signaling molecules was detected using western blot analysis. In addition, the cell surface area and the nuclear translocation of target proteins were evaluated using immunofluorescence. The results of the present study demonstrated that lercanidipine and FK506 inhibited Ang II‑induced cardiomyocyte hypertrophy, as evidenced by decreases in fetal gene (atrial natriuretic peptide and brain natriuretic peptide) expression levels and cell surface area. Notably, lercanidipine suppressed Ang II‑induced activation of calcineurin A (CnA) and nuclear factor of activated T cells 3 (NFAT3). In addition, calcium/calmodulin‑dependent kinase II (CaMKII)‑histone deacetylase 4 (HDAC4) signaling was also inhibited by lercanidipine. In conclusion, the present study demonstrated that lercanidipine may ameliorate cardiomyocyte hypertrophy, possibly partially by blocking Cn-NFAT3 and CaMKII-HDAC4 signaling.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Calcineurin; Calcium Channel Blockers; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Cardiomegaly; Cells, Cultured; Dihydropyridines; Gene Expression Regulation; Histone Deacetylases; Myocytes, Cardiac; Natriuretic Peptide, Brain; NFATC Transcription Factors; Rats; Signal Transduction

Endothelial-to-mesenchymal transition (EndMT) is a mechanism that promotes cardiac fibrosis induced by Angiotensin II (AngII). Kaempferol (KAE) is a monomer component mainly derived from the rhizome of Kaempferia galanga L. It shows anti-inflammatory, anti-oxidative, anti-microbial and anti-cancer properties, which can be used in the treatment of cancer, cardiovascular diseases, infection, etc. But, its effects on the development of cardiac remodelling remain completely unknown. The aim of the present study was to determine whether KAE attenuates cardiac hypertrophy induced by angiotensin II (Ang II) in cultured neonatal rat cardiac myocytes in vitro and cardiac hypertrophy induced by AngII infusion in mice in vivo.. Male wild-type mice aged 8-10 weeks with or without KAE were subjected to AngII or saline, to induce fibrosis or as a control, respectively. Morphological changes, echocardiographic parameters, histological analyses, and hypertrophic markers were also used to evaluate hypertrophy.. KAE prevented and reversed cardiac remodelling induced by AngII. The KAE in this model exerted no basal effects but attenuated cardiac fibrosis, hypertrophy and dysfunction induced by AngII. Both in vivo and in vitro experiments demonstrated that Ang II infusion or TGF-β induced EndMT can be reduced by KAE and the proliferation and activation of cardiac fibroblasts (CFs) can be inhibited by KAE.. The results suggest that KAE prevents and reverses ventricular fibrosis and cardiac dysfunction, providing an experimental basis for clinical treatment on ventricular fibrosis.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Cardiomegaly; Cell Survival; Cells, Cultured; Collagen Type I; Collagen Type II; Echocardiography; Fibroblasts; Fibrosis; Heart Ventricles; Human Umbilical Vein Endothelial Cells; Humans; Kaempferols; Male; Mice; Mice, Inbred C57BL; Microscopy, Fluorescence; Mitogen-Activated Protein Kinases; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats; Signal Transduction; Transforming Growth Factor beta1; Ventricular Remodeling

This study aimed to exploit the potential therapeutic value of palmatine in treatment of cardiac hypertrophy and the underlying molecular mechanism. Rat hypertrophy model was established by intraperitoneal isoproterenol (ISO) injection. The hypertrophy was evaluated with cardiac hypertrophic parameters, hemodynamic parameters, lipid profile, and non-specific cardiac markers. The animals were intraperitoneally administrated with either palmatine or vehicle. The relative expressions of ANP, BNP, HDAC2, HDAC5, KLF4, and INPP5F transcripts were determined by real-time polymerase chain reaction (PCR). The relative protein levels of HDAC2, HDAC5, KLF4, and INPP5F were analyzed by immunoblotting. Palmatine treatment significantly attenuated ISO-induced hypertrophy in rats and elicited remarkable repressions in ANP, BNP, and HDAC2 transcriptions but not HDAC5. The downstream effector genes KLF4 and INPP5F were greatly restored in a dose-dependent manner in response to palmatine treatment. Our data demonstrated that palmatine possessed promising therapeutic potential against hypertrophy, which was mediated by modulation of HDAC2-KLF4/INPP5F pathway.

Topics: Animals; Atrial Natriuretic Factor; Berberine Alkaloids; Cardiomegaly; Cardiotonic Agents; Histone Deacetylase 2; Histone Deacetylase Inhibitors; Inositol Polyphosphate 5-Phosphatases; Isoproterenol; Kruppel-Like Factor 4; Kruppel-Like Transcription Factors; Male; Natriuretic Peptide, Brain; Rats, Wistar; RNA, Messenger

BACKGROUND Heart failure in women increases around the time of menopause when high-fat diets may result in obesity. The heart produces brain natriuretic peptide (BNP), also known as B-type natriuretic peptide. This aims of this study were to assess cardiac hypertrophy and BNP levels in ovariectomized rats fed a high-fat diet. MATERIAL AND METHODS Forty-eight female Wistar rats were divided into four groups: sham-operated rats fed a control diet (SC) (n=12); ovariectomized rats fed a control diet (OC) (n=12); sham-operated rats fed a high-fat diet (SF) (n=12); and ovariectomized rats fed a high-fat diet (OF) (n=12). Body weight and blood pressure were measured weekly for 24 weeks. Rats were then euthanized, and plasma samples and heart tissue were studied for gene expression, hydroxyproline levels, and histological examination. RESULTS A high-fat diet and ovariectomy (group OF) increased the weight body and the systolic blood pressure after three months and five months, respectively. Cardiomyocyte hypertrophy was associated with increased expression of ventricular BNP, decreased natriuretic peptide receptor (NPR)-A and increased levels of hydroxyproline and transforming growth factor (TGF)-β. The plasma levels of BNP and estradiol were inversely correlated; expression of estrogen receptor (ER)β and ERα were reduced. CONCLUSIONS The findings of this study showed that, in the ovariectomized rats fed a high-fat diet, the BNP-NPR-A receptor complex was involved in cardiac remodeling. BNP may be a marker of cardiac hypertrophy in this animal model.

Topics: Animals; Blood Pressure; Body Weight; Cardiomegaly; Diet, High-Fat; Disease Models, Animal; Estradiol; Female; Gene Expression; Heart Ventricles; Myocytes, Cardiac; Natriuretic Peptide, Brain; Obesity; Ovariectomy; Rats; Rats, Wistar; Receptors, Atrial Natriuretic Factor

Topics: 3' Untranslated Regions; Angiotensin II; Animals; Atrial Natriuretic Factor; Calmodulin; Cardiomegaly; Cells, Cultured; MicroRNAs; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats; Real-Time Polymerase Chain Reaction; RNA, Messenger

Recent studies have evidenced the involvement of inflammation-related pathways to the development of cardiac hypertrophy and other consequences on the cardiovascular system, including the calcium-binding protein S100A8. However, this has never been investigated in the thyroid hormone (TH)-prompted cardiac hypertrophy. Thus, we aimed to test whether S100A8 and related signaling molecules, myeloid differentiation factor-88 (MyD88) and nuclear factor kappa B (NF-қB), could be associated with the cardiomyocyte hypertrophy induced by TH. Our results demonstrate that the S100A8/MyD88/NF-қB signaling pathway is activated in cardiomyocytes following TH stimulation. The knockdown of S100A8 and MyD88 indicates the contribution of those molecules to cardiomyocyte hypertrophy in response to TH, as evaluated by cell surface area, leucine incorporation assay, and gene expression. Furthermore, S100A8 and MyD88 are crucial mediators of NF-қB activation, which is also involved in the hypertrophic growth of TH-treated cardiomyocytes. Supporting the in vitro data, the contribution of NF-қB for TH-induced cardiac hypertrophy is confirmed in vivo, by using transgenic mice with cardiomyocyte-specific suppression of NF-қB. These data identify a novel pathway regulated by TH that mediates cardiomyocyte hypertrophy. However, the potential role of this new pathway in short and long-term cardiac effects of TH remains to be further investigated.. Inflammation-related signaling is activated by T3 in cardiomyocytes. S100A8 and MyD88 have a crucial role in cardiomyocyte hypertrophy by T3. S100A8 and MyD88 mediate NF-қB activation by T3. NF-қB contributes to T3-induced cardiac hypertrophy in vitro and in vivo.

Topics: Animals; Atrial Natriuretic Factor; Calgranulin A; Cardiomegaly; Cells, Cultured; Male; Mice, Inbred C57BL; Mice, Transgenic; Myeloid Differentiation Factor 88; Myocytes, Cardiac; Natriuretic Peptide, Brain; NF-kappa B; Rats, Wistar; RNA, Messenger; RNA, Small Interfering; Signal Transduction; Toll-Like Receptor 4; Triiodothyronine

Recent studies have established the role of mid-chain hydroxyeicosatetraenoic acids (HETEs) in the development of cardiovascular disease. Mid-chain HETEs have been reported to have vasoconstrictive and pro-inflammatory effects. However, whether mid-chain HETEs can induce cardiac hypertrophy remains unclear. Therefore, the overall objective of the present study was to elucidate the potential hypertrophic effect of mid-chain HETEs in the human ventricular cardiomyocytes, RL-14 cells, and to explore the mechanisms involved. For this purpose, RL-14 cells were treated with increasing concentrations of mid-chain HETEs (2.5, 5, 10 and 20 µM). Thereafter, the cardiac hypertrophy markers and cell size were determined using real-time polymerase chain reaction and phase contrast imaging, respectively. Phosphorylated mitogen-activated protein kinase (MAPK) level and nuclear factor kappa B (NF-κB) binding activity were determined. Our results showed that mid-chain HETEs induced cellular hypertrophy in RL-14 cells as evidenced by the induction of cardiac hypertrophy markers, α- and β-myocin heavy chain and atrial and brain natriuretic peptide as well as the increase in cell size. Mechanistically, all mid-chain HETEs were able to induce the binding activity of NF-κB to its responsive element in a HETE-dependent manner, and they significantly induced the phosphorylation of ERK 1/2. The induction of cellular hypertrophy was associated with proportional increase in the formation of dihydroxyeicosatrienoic acids parallel to the increase of soluble epoxide hydrolase enzyme activity. In conclusion, our study provides the first evidence that mid-chain HETEs induce cellular hypertrophy in RL-14 cells through MAPK- and NF-κB-dependent mechanism.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Arachidonic Acid; Atrial Natriuretic Factor; Cardiomegaly; Cell Line; Cell Size; Cell Survival; Dose-Response Relationship, Drug; Heart Ventricles; Humans; Hydroxyeicosatetraenoic Acids; Mitogen-Activated Protein Kinases; Myocytes, Cardiac; Natriuretic Peptide, Brain; NF-kappa B

There is increasing evidence that left atrial dysfunction or cardiopathy is associated with ischemic stroke risk independently of atrial fibrillation. We aimed to determine the prevalence of atrial cardiopathy biomarkers in patients with cryptogenic stroke.. We included consecutive patients with ischemic stroke enrolled in the New York Columbia Collaborative Specialized Program of Translational Research in Acute Stroke registry between December 1, 2008, and April 30, 2012. Medical records were reviewed and patients with a diagnosis of cryptogenic stroke were identified. Atrial cardiopathy was defined as at least one of the following: serum N-terminal probrain natriuretic peptide (NT-proBNP) level greater than 250 pg/mL, P-wave terminal force velocity in lead V1 (PTFV1) on electrocardiogram (ECG) greater than 5000 µV⋅ms, or severe left atrial enlargement (LAE) on echocardiogram. We compared clinical, echocardiographic, and radiological characteristics between patients with and without atrial cardiopathy.. Among 40 patients with cryptogenic stroke, 63% had at least one of the biomarkers of atrial cardiopathy; 49% had elevated NT-proBNP levels, 20% had evidence of increased PTFV1 on ECG, and 5% had severe LAE. Patients with atrial cardiopathy were more likely to be older (76 versus 62 years, P = .012); have hypertension (96% versus 33%, P < .001), hyperlipidemia (60% versus 27%, P = .05), or coronary heart disease (28% versus 0%, P = .033); and less likely to have a patent foramen ovale (4% versus 40%, P = .007).. There is a high prevalence of biomarkers indicative of atrial cardiopathy in patients with cryptogenic stroke. Clinical trials are needed to determine whether these patients may benefit from anticoagulation to prevent stroke.

Topics: Adult; Aged; Aged, 80 and over; Atrial Fibrillation; Atrial Function, Left; Biomarkers; Brain Ischemia; Cardiomegaly; Comorbidity; Coronary Disease; Cross-Sectional Studies; Electrocardiography; Female; Foramen Ovale, Patent; Heart Diseases; Humans; Hyperlipidemias; Hypertension; Kidney Diseases; Male; Middle Aged; Natriuretic Peptide, Brain; Peptide Fragments; Pilot Projects; Prevalence; Prospective Studies; Registries; Smoking; Ultrasonography; Young Adult

Cardiovascular (CV) toxicity is an important cause of failure during drug development. Blood-based biomarkers can be used to detect CV toxicity during preclinical development and prioritize compounds at lower risk of causing such toxicities. Evidence of myocardial degeneration can be detected by measuring concentrations of biomarkers such as cardiac troponin I and creatine kinase in blood; however, detection of functional changes in the CV system, such as blood pressure, generally requires studies in animals with surgically implanted pressure transducers. This is a significant limitation because sustained changes in blood pressure are often accompanied by changes in heart rate and together can lead to cardiac hypertrophy and myocardial degeneration in animals, and major adverse cardiovascular events (MACE) in humans. Increased concentrations of NPs in blood correlate with higher risk of cardiac mortality, all-cause mortality, and MACE in humans. Their utility as biomarkers of CV function and toxicity in rodents was investigated by exploring the relationships between plasma concentrations of NTproANP and NTproBNP, blood pressure, heart rate, and heart weight in Sprague Dawley rats administered compounds that caused hypotension or hypertension, including nifedipine, fluprostenol, minoxidil, L-NAME, L-thyroxine, or sunitinib for 1-2 weeks. Changes in NTproANP and/or NTproBNP concentrations were inversely correlated with changes in blood pressure. NTproANP and NTproBNP concentrations were inconsistently correlated with relative heart weights. In addition, increased heart rate was associated with increased heart weights. These studies support the use of natriuretic peptides and heart rate to detect changes in blood pressure and cardiac hypertrophy in short-duration rat studies.

Topics: Animals; Atrial Natriuretic Factor; Biomarkers; Blood Pressure; Cardiomegaly; Heart Rate; Indoles; Male; Minoxidil; Natriuretic Peptide, Brain; NG-Nitroarginine Methyl Ester; Nifedipine; Organ Size; Peptide Fragments; Prostaglandins F, Synthetic; Pyrroles; Rats; Rats, Sprague-Dawley; Sunitinib; Thyroxine

Mitochondrial dysfunction has been implicated as a cause of energy deprivation in heart failure (HF). Herein, we tested individual and combined effects of two pathogenic factors of nonischemic HF, inhibition of nitric oxide synthesis [with l-N(G)-nitroarginine methyl ester (l-NAME)] and hypertension [with angiotensin II (AngII)], on myocardial mitochondrial function, oxidative stress, and metabolic gene expression. l-NAME and AngII were administered individually and in combination to mice for 5 wk. Although all treatments increased blood pressure and reduced cardiac contractile function, the l-NAME + AngII group was associated with the most severe HF, as characterized by edema, hypertrophy, oxidative stress, increased expression of Nppa and Nppb, and decreased expression of Atp2a2 and Camk2b. l-NAME + AngII-treated mice exhibited robust deterioration of cardiac mitochondrial function, as observed by reduced respiratory control ratios in subsarcolemmal mitochondria and reduced state 3 levels in interfibrillar mitochondria for complex I but not for complex II substrates. Cardiac myofibrils showed reduced ADP-supported and oligomycin-inhibited oxygen consumption. Mitochondrial functional impairment was accompanied by reduced mitochondrial DNA content and activities of pyruvate dehydrogenase and complex I but increased H2O2 production and tissue protein carbonyls in hearts from AngII and l-NAME + AngII groups. Microarray analyses revealed the majority of the gene changes attributed to the l-NAME + AngII group. Pathway analyses indicated significant changes in metabolic pathways, such as oxidative phosphorylation, mitochondrial function, cardiac hypertrophy, and fatty acid metabolism in l-NAME + AngII hearts. We conclude that l-NAME + AngII is associated with impaired mitochondrial respiratory function and increased oxidative stress compared with either l-NAME or AngII alone, resulting in nonischemic HF.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Cardiomegaly; DNA, Mitochondrial; Electron Transport Complex I; Electron Transport Complex II; Enzyme Inhibitors; Gene Expression; Heart; Heart Failure; Hydrogen Peroxide; Mice; Mitochondria, Heart; Myocardium; Natriuretic Peptide, Brain; Natriuretic Peptide, C-Type; NG-Nitroarginine Methyl Ester; Nitric Oxide; Oxidative Stress; Protein Precursors; Pyruvate Dehydrogenase Complex; Reverse Transcriptase Polymerase Chain Reaction; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Vasoconstrictor Agents

This study examined the role of interleukin (IL)-10 in angiotensin II-induced cardiac remodeling.. Angiotensin II was infused subcutaneously (1.1mg/kg/day) for one week in IL-10 knockout and wild-type mice, after which cardiac function and hypertrophy were assessed by echocardiogram.. IL-10 gene expression in the heart was increased by angiotensin II infusion. Plasma levels of brain natriuretic peptide (BNP) and gene expression of BNP in the heart were increased by IL-10 deficiency or angiotensin II, and plasma BNP levels were further increased by IL-10 deficiency with angiotensin II. IL-10 deficiency increased the left ventricular dimension, whereas treatment with angiotensin II increased heart weight. Angiotensin II significantly reduced cardiac function in IL-10 knockout mice compared with wild-type mice. Gene expression of tumor necrosis factor-α and interleukin-6 was increased by IL-10 deficiency or angiotensin II infusion, and these increases were further enhanced by IL-10 deficiency with angiotensin II. Gene expression of collagen I/III and collagen III protein levels were increased by angiotensin II but not by IL-10 deficiency. Gene expression of matrix metalloproteinase2/9 was increased by IL-10 deficiency or angiotensin II, and this expression was further increased by IL-10 deficiency with angiotensin II. Akt phosphorylation was increased by IL-10 deficiency or angiotensin II and further increased by IL-10 deficiency with angiotensin II. Phosphorylation of p38 was increased by IL-10 deficiency.. These results suggest that IL-10 deficiency causes deterioration in cardiac functions in angiotensin II-infused mice, suggesting that IL-10 plays a protective role against angiotensin II-induced cardiac remodeling.

Topics: Angiotensin II; Animals; Cardiomegaly; Collagen; Interleukin-10; Interleukin-6; Matrix Metalloproteinases; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardium; Natriuretic Peptide, Brain; Oncogene Protein v-akt; Ultrasonography; Ventricular Remodeling

2-Deoxy-d-glucose (2-DG) is being developed as a potential anticonvulsant and disease-modifying agent for patients with epilepsy; however, during preclinical development, cardiac toxicity has been encountered in rats. This study was performed to determine whether cardiac troponin (cTnI and cTnT), atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), N-terminal pro-brain natriuretic peptide (NT-proBNP), and/or creatine kinase (CK) could be useful as indicators of 2-DG cardiac toxicity. In addition, this study also investigated the association of cardiac histopathological changes with these biomarkers. F344 rats (4/sex/group/sacrifice point) were gavaged with either vehicle or 2-DG (50, 125, or 375 mg/kg twice daily; total daily dose of 100, 250, or 750 mg/kg/d) for 7, 14, 21, or 45 days followed by a 15-day recovery. Dose-dependent increases in NT-proBNP and BNP plasma concentrations were observed. Following recovery period, the NT-proBNP and BNP concentrations returned to baseline levels. There were no remarkable increases in CK, ANP, cTnI, or cTnT concentrations. There were no gross cardiac lesions observed at the necropsy. Microscopic findings of vacuolar degeneration and hypertrophy of the endothelial cells of the endocardium were present in the heart at doses of 250 and 750 mg/kg/d. Microscopic findings, in general, were associated with increases in NT-proBNP levels. Cardiac toxicity appeared to be reversible. In conclusion, NT-proBNP and BNP are potential early biomarkers for 2-DG-induced cardiac toxicity that can be useful to monitor 2-DG therapy in clinical trials.

Topics: Animals; Biomarkers; Cardiomegaly; Deoxyglucose; Female; Heart; Male; Myocardium; Natriuretic Peptide, Brain; Peptide Fragments; Rats; Rats, Inbred F344; Vacuoles

Pharmacological blockade of mineralocorticoid receptors (MR) is known as an efficacious therapy in chronic heart failure. Therapy with steroidal MR antagonists such as spironolactone or eplerenone (EPL) is often limited because of side effects. Recently, a new highly selective and potent, nonsteroidal MR antagonist, finerenone (FIN), has been developed. To investigate the effects of FIN on pressure-induced cardiac hypertrophy, the transverse aortic constriction (TAC) model was used in C57BL/6 mice treated with FIN (10 mg·kg·d), EPL (200 mg·kg·d) or vehicle (VEH). First, we analyzed cardiac gene expression 4 weeks after TAC using a pathway-focused quantitative polymerase chain reaction array. FIN caused a distinct cardiac gene expression profile compared to VEH and EPL, including differential expression of BNP (brain natriuretic peptide) and Tnnt2 (troponin T type 2). FIN treatment led to a significant reduction of TAC-induced left ventricular (LV) wall thickening assessed by echocardiography. In accordance, FIN-treated mice showed a significant lower increase of calculated left ventricular mass compared with VEH- and EPL-treated mice (FIN: 28.4 ± 3.7 mg; EPL: 38.4 ± 4.3 mg; VEH: 39.3 ± 3.1 mg; P < 0.05). These data show beneficial effects of nonsteroidal MR antagonism by FIN on left ventricular mass development in pressure overload associated with a distinct cardiac gene expression profile.

Topics: Animals; Cardiomegaly; Disease Models, Animal; Eplerenone; Gene Expression; Male; Mice; Mice, Inbred C57BL; Mineralocorticoid Receptor Antagonists; Naphthyridines; Natriuretic Peptide, Brain; Spironolactone; Troponin T; Ventricular Remodeling

Backgroud: Myocardial fibrosis results in myocardial remodelling and dysfunction. Celastrol, a traditional oriental medicine, has been suggested to have cardioprotective effects. However, its underlying mechanism is unknown. This study investigated the ability of celastrol to prevent cardiac fibrosis and dysfunction and explored the underlying mechanisms.. Animal and cell models of cardiac fibrosis were used in this study. Myocardial fibrosis was induced by transverse aortic constriction (TAC) in mice. Cardiac hypertrophy and fibrosis were evaluated based on histological and biochemical measurements. Cardiac function was evaluated by echocardiography. The levels of transforming growth factor beta 1 (TGF-β1), extracellular signal regulated kinases 1/2 (ERK1/2) signalling were measured using Western blotting, while the expression of miR-21was analyzed by real-time qRT-PCR in vitro and in vivo. In vitro studies, cultured cardiac fibroblasts (CFs) were treated with TGF-β1 and transfected with microRNA-21(miR21).. Celastrol treatment reduced the increased collagen deposition and down-regulated α-smooth muscle actin (α-SMA), atrial natriuretic peptide (ANP), brain natriuretic peptides (BNP), beta-myosin heavy chain (β-MHC), miR-21 and p-ERK/ERK. Cardiac dysfunction was significantly attenuated by celastrol treatment in the TAC mice model. Celastrol treatment reduced myocardial fibroblast viability and collagen content and down-regulated α-SMA in cultured CFs in vitro. Celastrol also inhibited the miR-21/ERK signalling pathway. Celastrol attenuated miR-21 up-regulation by TGF-β1 and decreased elevated p-ERK/ERK levels in CFs transfected with miR-21.. MiR-21/ERK signalling could be a potential therapeutic pathway for the prevention of myocardial fibrosis. Celastrol ameliorates myocardial fibrosis and cardiac dysfunction, these probably related to miR-21/ERK signaling pathways in vitro and in vivo.

Topics: Actins; Animals; Atrial Natriuretic Factor; Cardiomegaly; Cell Survival; Collagen; Disease Models, Animal; Down-Regulation; Fibrosis; Heart Ventricles; Male; MAP Kinase Signaling System; Mice; MicroRNAs; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Myocardium; Natriuretic Peptide, Brain; Pentacyclic Triterpenes; Phosphorylation; Transforming Growth Factor beta1; Triterpenes; Up-Regulation

Qiliqiangxin (QL), a traditional Chinese medicine, has long been used to treat chronic heart failure. Previous studies demonstrated that QL could prevent cardiac remodeling and hypertrophy in response to hypertensive or ischemic stress. However, little is known about whether QL could modulate cardiac hypertrophy in vitro, and (if so) whether it is through modulation of specific hypertrophy-related microRNA.. The primary neonatal rat ventricular cardiomyocytes were isolated, cultured, and treated with phenylephrine (PE, 50 µmol/L, 48 h) to induce hypertrophy in vitro, in the presence or absence of pretreatment with QL (0.5 µg/ml, 48 h). The cell surface area was determined by immunofluorescent staining for α-actinin. The mRNA levels of hypertrophic markers including atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and β-myosin heavy chain (MYH7) were assayed by qRT-PCRs. The protein synthesis of cardiomyocytes was determined by the protein/DNA ratio. The miR-199a-5p expression level was quantified in PE-treated cardiomyocytes and heart samples from acute myocardial infarction (AMI) mouse model. MiR-199a-5p overexpression was used to determine its role in the anti-hypertrophic effect of QL on cardiomyocytes.. PE induced obvious enlargement of cell surface in cardiomyocytes, paralleling with increased ANP, BNP, and MYH7 mRNA levels and elevated protein/DNA ratio. All these changes were reversed by the treatment with QL. Meanwhile, miR-199a-5p was increased in AMI mouse heart tissues. Of note, the increase of miR-199a-5p in PE-treated cardiomyocytes was reversed by the treatment with QL. Moreover, overexpression of miR-199a-5p abolished the anti-hypertrophic effect of QL on cardiomyocytes.. QL prevents PE-induced cardiac hypertrophy. MiR-199a-5p is increased in cardiac hypertrophy, while reduced by treatment with QL. miR-199a-5p suppression is essential for the anti-hypertrophic effect of QL on cardiomyocytes.

Topics: Actinin; Animals; Atrial Natriuretic Factor; Cardiomegaly; Cells, Cultured; Disease Models, Animal; Down-Regulation; Drugs, Chinese Herbal; Medicine, Chinese Traditional; Mice; Mice, Inbred C57BL; MicroRNAs; Myocardial Infarction; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Oligonucleotides, Antisense; Phenylephrine; Rats; Rats, Sprague-Dawley

Activation of glucose-dependent insulinotropic polypeptide receptor (GIPR) has been shown to be protective against atherosclerosis. However, effects of GIP on the heart have remained unclear. To address this question, in vitro and in vivo experiments were conducted.. In isolated mouse cardiomyocytes, GIPR mRNA was detected by reverse transcription-polymerase chain reaction, and GIP stimulation increased adenosine 3',5'-cyclic monophosphate production. In apolipoprotein E-knockout mice, infusion of angiotensin II (AngII; 2,000 ng·kg(-1)·min(-1)) significantly increased the heart weights, and co-administration of GIP (25 nmol·kg(-1)·day(-1)) reversed this increase (both P<0.01). In the left ventricular walls, GIP suppressed AngII-induced cardiomyocyte hypertrophy by 34%, apoptosis by 77%, and interstitial fibrosis by 79% (all P<0.01). Furthermore, GIP reduced AngII-induced expression of transforming growth factor-β1 (TGF-β1) and hypoxia inducible factor-1α. In wild-type mice, cardiac hypertrophy was induced by AngII to a lesser extent, and prevented by GIP. In contrast, GIP did not show any cardioprotective effect against AngII-induced cardiac hypertrophy in GIPR-knockout mice. In an in vitro experiment using mouse cardiomyocytes, GIP suppressed AngII-induced mRNA expression of B-type natriuretic peptide and TGF-β1.. It was demonstrated that cardiomyocytes represent a direct target of GIP action in vitro, and that GIP ameliorated AngII-induced cardiac hypertrophy via suppression of cardiomyocyte enlargement, apoptosis, and fibrosis in vivo. (Circ J 2016; 80: 1988-1997).

Topics: Angiotensin II; Animals; Apolipoproteins E; Cardiomegaly; Cell Line; Fibrosis; Gastric Inhibitory Polypeptide; Gene Expression Regulation; Hypoxia-Inducible Factor 1, alpha Subunit; Mice; Mice, Knockout; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Transforming Growth Factor beta1

Cucurbitacin-I, a natural triterpenoids initially identified in medicinal plants, shows a potent anticancer effect on a variety of cancer cell types. Nevertheless, the cardiotoxicity of cucurbitacin-I has not heretofore been reported. In this study, the mechanisms of cucurbitacin-I-induced cardiotoxicity were examined by investigating the role of MAPK-autophagy-dependent pathways. After being treated with 0.1-0.3μM cucurbitacin-I for 48h, H9c2 cells showed a gradual decrease in the cell viabilities, a gradual increase in cell size, and mRNA expression of ANP and BNP (cardiac hypertrophic markers). Cucurbitacin-I concentration-dependent apoptosis of H9c2 cells was also observed. The increased apoptosis of H9c2 cells was paralleling with the gradually strong autophagy levels. Furthermore, an autophagy inhibitor, 3-MA, was used to block the cucurbitacin-I-stirred autophagy, and then the hypertrophy and apoptosis induced by 0.3μM cucurbitacin-I were significantly attenuated. In addition, cucurbitacin-I exposure also activated the MAPK signaling pathways, including ERK1/2, JNK, and p38 kinases. Interestingly, only the ERK inhibitor U0126, but not the JNK inhibitor SP600125 and p38 MAPK inhibitor SB203580, weakened the induction of 0.3μM cucurbitacin-I in hypertrophy, autophagy and apoptosis. Our findings suggest that cucurbitacin-I can increase the autophagy levels of H9c2 cells, most likely, through the activation of an ERK-autophagy dependent pathway, which results in the hypertrophy and apoptosis of cardiomyocytes.

Topics: Atrial Natriuretic Factor; Autophagy; Cardiomegaly; Cell Size; Cell Survival; Humans; Imidazoles; MAP Kinase Kinase 4; MAP Kinase Kinase Kinases; MAP Kinase Signaling System; Myoblasts, Cardiac; Natriuretic Peptide, Brain; Protein Kinase Inhibitors; Pyridines; Signal Transduction; Triterpenes

To investigate the effects of renal denervation (RDN) on multi-organ fibrosis and vascular remodeling in cardiomyopathy.. Thirty-six male Sprague-Dawley rats underwent transverse aortic constriction (TAC). Five weeks later, 28 surviving TAC rats were randomly assigned to three groups: (1) RDN, (2) Sham, (3) Carvedilol. Six male Sham TAC rats served as the Control. Ten weeks after TAC, samples were collected.. TAC rats showed an increased diastolic interventricular septal thickness at week 5. At 10 weeks, Masson staining showed that left ventricular and renal glomerular fibrosis were significantly reduced in RDN compared with Sham group. In comparison to Sham group, hepatic perivascular fibrosis was attenuated in both RDN and Carvedilol group, so were the media thickness and the media/lumen of aorta. The plasma levels of B-type natriuretic peptide (BNP), Cystatin C (Cys-C), Alanine Transaminase, angiotensin II (Ang II), transforming growth factor beta 1 (TGF-β1), and malondialdehyde increased, and total superoxide dismutase (T-SOD) decreased in Sham but not in RDN group, compared with Control group. Both RDN and Carvedilol reduced the Cys-C and TGF-β1 levels, and restored T-SOD concentration, compared with Sham group. While only RDN lowered the plasma levels of BNP and Ang II. No significant effects of RDN on blood pressure (BP) and heart rate (HR) were oberved.. RDN can attenuate multi-organ fibrosis and improve vascular remodeling independent of BP and HR change in TAC-induced cardiomyopathy. These effects of RDN may be associated with the direct inhibition of renin-angiotensin-aldosterone system and oxidative stress.

Topics: Alanine Transaminase; Angiotensin II; Animals; Aorta; Blood Pressure; Carbazoles; Cardiomegaly; Cardiomyopathies; Carvedilol; Constriction; Cystatin C; Denervation; Fibrosis; Heart Rate; Kidney; Malondialdehyde; Natriuretic Peptide, Brain; Organ Specificity; Oxidative Stress; Peptide Fragments; Procollagen; Propanolamines; Rats, Sprague-Dawley; Superoxide Dismutase; Transforming Growth Factor beta1; Vascular Remodeling

Cardiac hypertrophy is a compensatory mechanism that occurs in conjunction with cardiovascular diseases. Although hypertrophy of the myocardium provides certain benefits during the early stages of cardiovascular disease, prolonged hypertrophy is potentially harmful to the heart and can result in arrhythmia and heart failure. The aim of this study was to investigate whether an ATP‑sensitive K+ (KATP) channel agonist was capable of reducing isoproterenol (Iso)‑induced cardiac hypertrophy and modulating myocardial connexin43 (Cx43) expression. Fifty male Sprague Dawley rats were randomly assigned to five groups: Normal, vehicle, nicorandil, glibenclamide and nicorandil plus glibenclamide. Rats in the four treatment groups received Iso injection for seven days, followed by administration with saline, nicorandil, glibenclamide or a combination of nicorandil and glibenclamide, respectively, for four weeks. Cardiac hypertrophy was then evaluated by measuring body weight, heart weight and left‑ventricular weight, and plasma B‑type natriuretic peptide levels were evaluated by ELISA. Immunocytochemistry and a reverse transcription‑polymerase chain reaction were performed to detect the spatial distribution and gene expression of myocardial Cx43, respectively. The KATP channel agonist nicorandil markedly attenuated the degree of myocardial hypertrophy induced by Iso as compared with the vehicle group. Myocardial Cx43 expression was significantly decreased and redistributed following cardiac hypertrophy. The decrease and redistribution of Cx43 was reduced following treatment with the KATP channel agonist nicorandil. Addition of the KATP channel blocker glibenclamide eliminated the beneficial effects of nicorandil against hypertrophy and on connexin43. In conclusion, the present study indicated that chronic use of KATP channel agonists following cardiac hypertrophy can attenuate ventricular remodeling and upregulate the expression level and spatial distribution of Cx43.

Topics: Animals; Cardiomegaly; Connexin 43; Disease Models, Animal; Gene Expression; Heart Ventricles; Immunohistochemistry; Isoproterenol; KATP Channels; Male; Myocardium; Natriuretic Peptide, Brain; Nicorandil; Rats; RNA, Messenger

Evidence suggests that upregulation of soluble epoxide hydrolase (sEH) is associated with the development of myocardial infarction, dilated cardiomyopathy, cardiac hypertrophy, and heart failure. However, the upregulation mechanism is still unknown. In this study, we treated H9C2 cells with buthionine sulfoximine (BSO) to explore whether oxidative stress upregulates sEH gene expression and to identify the molecular and cellular mechanisms behind this upregulatory response. Real-time PCR and Western blot analyses were used to measure mRNA and protein expression, respectively. We demonstrated that BSO significantly upregulated sEH at mRNA levels in a concentration- and time-dependent manner, leading to a significant increase in the cellular hypertrophic markers, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). Furthermore, BSO significantly increased the cytosolic phosphorylated IκB-α and translocation of NF-κB p50 subunits, as measured by Western blot analysis. This level of translocation was paralleled by an increase in the DNA-binding activity of NF-κB P50 subunits. Moreover, our results demonstrated that pretreatment with the NF-κB inhibitor PDTC significantly inhibited BSO-mediated induction of sEH and cellular hypertrophic marker gene expression in a dose-dependent manner. Additionally, mitogen-activated protein kinases (MAPKs) were transiently phosphorylated by BSO treatment. To understand further the role of MAPKs pathway in BSO-mediated induction of sEH mRNA, we examined the role of extracellular signal-regulated kinase (ERK), c-JunN-terminal kinase (JNK), and p38 MAPK. Indeed, treatment with the MEK/ERK signal transduction inhibitor, PD98059, partially blocked the activation of IκB-α and translocation of NF-κB p50 subunits induced by BSO. Moreover, pretreatment with MEK/ERK signal transduction inhibitors, PD98059 and U0126, significantly inhibited BSO-mediated induction of sEH and cellular hypertrophic marker gene expression. These results clearly demonstrated that the NF-κB signaling pathway is involved in BSO-mediated induction of sEH gene expression, and appears to be associated with the activation of the MAPK pathway. Furthermore, our findings provide a strong link between sEH-induced cardiac dysfunction and involvement of NF-κB in the development of cellular hypertrophy.

Topics: Animals; Antioxidants; Atrial Natriuretic Factor; Butadienes; Buthionine Sulfoximine; Cardiomegaly; Cell Line; Cell Survival; Enzyme Activation; Epoxide Hydrolases; Extracellular Signal-Regulated MAP Kinases; Flavonoids; Gene Expression Regulation; Glutathione; Heart Failure; I-kappa B Proteins; JNK Mitogen-Activated Protein Kinases; MAP Kinase Signaling System; Myoblasts, Cardiac; Natriuretic Peptide, Brain; NF-kappa B p50 Subunit; NF-KappaB Inhibitor alpha; Nitriles; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Proline; Rats; RNA, Messenger; Thiocarbamates; Transcription Factor RelA; Up-Regulation

The orphan nuclear receptor NOR1 belongs to the NR4A subfamily of the nuclear hormone receptor superfamily, and is involved in glucose and fat metabolism. However, its potential contribution to cardiovascular diseases remains to be assessed. Here, the roles of NOR1 in cardiac hypertrophy induced by isoprenaline and the underlying molecular mechanisms were investigated.. NOR1 was expressed in cardiomyocytes treated with isoprenaline. After NOR1 overexpression or knockdown in neonatal rat cardiomyocytes, cellular hypertrophy was monitored by measuring cell surface area and the mRNA of hypertrophic biomarkers. Interactions between NOR1 and PARP-1 were investigated by co-immunoprecipitation. NOR1 expression and PARP-1 activity were measured in rats with cardiac hypertrophy induced by isoprenaline.. Treatment with isoprenaline significantly up-regulated NOR1 expression and PARP-1 activity both in vivo and in vitro. Specific gene silencing of NOR1 attenuated isoprenaline-induced cardiomyocyte hypertrophy, whereas NOR1 overexpression exacerbated cardiac hypertrophy. We identified a physical interaction between NOR1 and PARP-1, which was enhanced by NOR1 transfection and thereby led to PARP-1 activation. Overexpression of NOR1, but not C293Y, a NOR1 mutant lacking the PARP-1 binding activity, increased cellular surface area and the mRNA levels of atrial natriuretic factor and brain natriuretic polypeptide, effects blocked by the PARP-1 inhibitor 3-aminobenzamide or siRNA for PARP-1.. This is the first evidence that NOR1 was involved in isoprenaline-induced cardiac hypertrophy. The pro-hypertrophic effect of NOR1 can be partly attributed to its regulation of PARP-1 enzymic activity.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Cells, Cultured; DNA-Binding Proteins; Gene Knock-In Techniques; Gene Knockdown Techniques; Immunoprecipitation; In Vitro Techniques; Isoproterenol; Myocytes, Cardiac; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Rats; RNA, Messenger; Sympathomimetics; Up-Regulation

Hydrogen peroxide (H2O2) causes cell damage via oxidative stress. Heme oxygenase-1 (HO-1) is an antioxidant enzyme that can protect cardiomyocytes against oxidative stress. In this study, we investigated whether the heme precursor 5-aminolevulinic acid (5-ALA) with sodium ferrous citrate (SFC) could protect cardiomyocytes from H2O2-induced hypertrophy via modulation of HO-1 expression. HL-1 cells pretreated with/without 5-ALA and SFC were exposed to H2O2 to induce a cardiomyocyte hypertrophy model. Hypertrophy was evaluated by planar morphometry, (3)H-leucine incorporation, and RT-PCR analysis of hypertrophy-related gene expressions. Reactive oxygen species (ROS) production was assessed by 5/6-chloromethyl-2',7'-ichlorodihydrofluorescein diacetate acetylester. HO-1 and nuclear factor erythroid 2-related factor 2 (Nrf2) protein expressions were analyzed by Western blot. In our experiments, HL-1 cells were transfected with Nrf2 siRNA or treated with a signal pathway inhibitor. We found several results. 1) ROS production, cell surface area, protein synthesis, and expressions of hypertrophic marker genes, including atrial natriuretic peptide, brain natriuretic peptide, atrial natriuretic factor, and β-myosin heavy chain, were decreased in HL-1 cells pretreated with 5-ALA and SFC. 2) 5-ALA and SFC increased HO-1 expression in a dose- and time-dependent manner, associated with upregulation of Nrf2. Notably, Nrf2 siRNA dramatically reduced HO-1 expression in HL-1 cells. 3) ERK1/2, p38, and SAPK/JNK signaling pathways were activated and modulate 5-ALA- and SFC-enhanced HO-1 expression. SB203580 (p38 kinase), PD98059 (ERK), or SP600125 (JNK) inhibitors significantly reduced this effect. In conclusion, our data suggest that 5-ALA and SFC protect HL-1 cells from H2O2-induced cardiac hypertrophy via activation of the MAPK/Nrf2/HO-1 signaling pathway.

Topics: Aminolevulinic Acid; Animals; Antioxidants; Atrial Natriuretic Factor; Cardiomegaly; Cell Line; Citric Acid; Ferrous Compounds; Heme Oxygenase-1; Hydrogen Peroxide; Membrane Proteins; Mice; Mitogen-Activated Protein Kinases; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; NF-E2-Related Factor 2; Oxidative Stress; RNA Interference; RNA, Small Interfering; Signal Transduction; Ventricular Myosins

Doxorubicin (DOX) is known to induce serious cardiotoxicity, which is believed to be mediated by oxidative stress and complex interactions with iron. However, the relationship between iron and DOX-induced cardiotoxicity remains controversial and the role of iron chelation therapy to prevent cardiotoxicity is called into question. Firstly, we evaluated in vitro the effects of DOX in combination with dextran-iron on cell viability in cultured H9c2 cardiomyocytes and EMT-6 cancer cells. Secondly, we used an in vivo murine model of iron overloading (IO) in which male C57BL/6 mice received a daily intra-peritoneal injection of dextran-iron (15mg/kg) for 3weeks (D0-D20) and then (D21) a single sub-lethal intra-peritoneal injection of 6mg/kg of DOX. While DOX significantly decreased cell viability in EMT-6 and H9c2, pretreatment with dextran-iron (125-1000μg/mL) in combination with DOX, paradoxically limited cytotoxicity in H9c2 and increased it in EMT-6. In mice, IO alone resulted in cardiac hypertrophy (+22%) and up-regulation of brain natriuretic peptide and β-myosin heavy-chain (β-MHC) expression, as well as an increase in cardiac nitro-oxidative stress revealed by electron spin resonance spectroscopy. In DOX-treated mice, there was a significant decrease in left-ventricular ejection fraction (LVEF) and an up-regulation of cardiac β-MHC and atrial natriuretic peptide (ANP) expression. However, prior IO did not exacerbate the DOX-induced fall in LVEF and there was no increase in ANP expression. IO did not impair the capacity of DOX to decrease cancer cell viability and could even prevent some aspects of DOX cardiotoxicity in cardiomyocytes and in mice.

Topics: Animals; Cardiomegaly; Cardiotoxicity; Cell Line; Cell Line, Tumor; Cell Survival; Dextrans; Doxorubicin; Heart Ventricles; Iron; Iron Overload; Male; Mice; Mice, Inbred C57BL; Myocytes, Cardiac; Natriuretic Peptide, Brain; Oxidative Stress; Up-Regulation; Ventricular Myosins

We previously reported that Astragaloside IV (ASIV), a major active constituent of Astragalus membranaceus (Fisch) Bge protects against cardiac hypertrophy in rats induced by isoproterenol (Iso), however the mechanism underlying the protection remains unknown. Dysfunction of cardiac energy biosynthesis contributes to the hypertrophy and Nuclear Factor κB (NF-κB)/Peroxisome Proliferator-Activated Receptor-γ Coactivator 1α (PGC-1α) signaling gets involved in the dysfunction. The present study was designed to investigate the mechanism by which ASIV improves the cardiac hypertrophy with focuses on the NF-κB/PGC-1α signaling mediated energy biosynthesis. Sprague-Dawley (SD) rats or Neonatal Rat Ventricular Myocytes (NRVMs) were treated with Iso alone or in combination with ASIV. The results showed that combination with ASIV significantly attenuated the pathological changes, reduced the ratios of heart weight/body weight and Left ventricular weight/body weight, improved the cardiac hemodynamics, down-regulated mRNA expression of Atrial Natriuretic Peptide (ANP) and Brain Natriuretic Peptide (BNP), increased the ratio of ATP/AMP, and decreased the content of Free Fat Acid (FFA) in heart tissue of rats compared with Iso alone. In addition, pretreatment with ASIV significantly decreased the surface area and protein content, down-regulated mRNA expression of ANP and BNP, increased the ratio of ATP/AMP, and decreased the content of FFA in NRVMs compared with Iso alone. Furthermore, ASIV increased the protein expression of ATP5D, subunit of ATP synthase and PGC-1α, inhibited translocation of p65, subunit of NF-κB into nuclear fraction in both rats and NRVMs compared with Iso alone. Parthenolide (Par), the specific inhibitor of p65, exerted similar effects as ASIV in NRVMs. Knockdown of p65 with siRNA decreased the surface areas and increased PGC-1α expression of NRVMs compared with Iso alone. The results suggested that ASIV protects against Iso-induced cardiac hypertrophy through regulating NF-κB/PGC-1α signaling mediated energy biosynthesis.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Down-Regulation; Energy Metabolism; Gene Knockdown Techniques; Heart Ventricles; Hemodynamics; Isoproterenol; Male; Mitochondria; Myocytes, Cardiac; Natriuretic Peptide, Brain; NF-kappa B; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Rats; Rats, Sprague-Dawley; RNA, Messenger; RNA, Small Interfering; Saponins; Signal Transduction; Transcription Factor RelA; Transcription Factors; Triterpenes

Pathological cardiac hypertrophy, a common response of the heart to a variety of cardiovascular diseases, is typically associated with myocytes remodeling and fibrotic replacement, cardiac dysfunction. Exercise preconditioning (EP) increases the myocardial mechanical load and enhances tolerance of cardiac ischemia-reperfusion injury (IRI), however, is less reported in pathological cardiac hypertrophy. To determine the effect of EP in pathological cardiac hypertrophy, Male 10-wk-old Sprague-Dawley rats (n=30) were subjected to 4 weeks of EP followed by 4-8 weeks of pressure overload (transverse aortic constriction, TAC) to induce pathological remodeling. TAC in untrained controls (n=30) led to pathological cardiac hypertrophy, depressed systolic function. We observed that left ventricular wall thickness in end diastole, heart size, heart weight-to-body weight ratio, heart weight-to-tibia length ratio, cross-sectional area of cardiomyocytes and the reactivation of fetal genes (atrial natriuretic peptide and brain natriuretic peptide) were markedly increased, meanwhile left ventricular internal dimension at end-diastole, systolic function were significantly decreased by TAC at 4 wks after operation (P < 0.01), all of which were effectively inhibited by EP treatment (P < 0.05), but the differences of these parameters were decreased at 8 wks after operation. Furthermore, EP treatment inhibited degradation of IκBα, and decreased NF-κB p65 subunit levels in the nuclear fraction, and then reduced IL2 levels in the myocardium of rats subject to TAC. EP can effectively attenuate pathological cardiac hypertrophic responses induced by TAC possibly through inhibition of degradation of IκB and blockade of the NF-κB signaling pathway in the early stage of pathological cardiac hypertrophy.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; I-kappa B Proteins; Male; Myocardium; Natriuretic Peptide, Brain; Physical Conditioning, Animal; Rats; Rats, Sprague-Dawley; Signal Transduction

3,3'-Diindolylmethane (DIM) is the major product of the acid-catalyzed condensation of indole-3-carbinol (I3C), a component of extracts of Brassica food plants. Numerous studies have suggested that DIM has several beneficial biological activities, including elimination of free radicals, antioxidant and anti-angiogenic effects and activation of apoptosis of various tumor cells. In the present study, an in vitro model was established, using 1 µM angiotensin II (Ang II) in cultured rat cardiac H9c2 cells, to observe the effects of DIM on cardiac hypertrophy. Following 24 h stimulation with DIM (1, 5, and 10 µM) with or without Ang II, cells were characterized by immunofluorescence to analyze cardiac α-actinin expression. Cardiomyocyte hypertrophy and molecular markers of cardiac hypertrophy were assessed by quantitative polymerase chain reaction. Atrial natriuretic peptide, brain natriuretic peptide and myosin heavy chain β mRNA expression were induced by Ang II in H9c2 cells treated with the optimal concentration of DIM for 6, 12, and 24 h. The levels of phosphorylated and total proteins of the 5' AMP-activated protein kinase α (AMPKα)/mitogen-activated protein kinase (MAPK)/mechanistic target of rapamycin (mTOR) signaling pathways in H9c2 cells treated with DIM for 0, 15, 30, and 60 min induced by Ang II were determined by western blot analysis. The results showed that DIM attenuated cellular hypertrophy in vitro, enhanced the phosphorylation of AMPKα and inhibited the MAPK‑mTOR signaling pathway in response to hypertrophic stimuli.

Topics: AMP-Activated Protein Kinases; Angiotensin II; Animals; Atrial Natriuretic Factor; Cardiomegaly; Cardiotonic Agents; Cell Line; Gene Expression Regulation; Indoles; Models, Biological; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Phosphorylation; Rats; Signal Transduction; TOR Serine-Threonine Kinases; Vasoconstrictor Agents

Angiotensin II (Ang II) is an important inflammatory mediator. Ang II induces cyclooxygenase-2 (COX-2) expression and prostaglandin F2α release followed by cardiac hypertrophy. Inhibition of COX-2 may modulate high blood pressure but controversy still exists. The aim of this study was to determine the role of COX-2 in the regulation of blood pressure and to define the mechanisms in two kidney one-clip hypertensive (2K1C) rats. Chronic treatment with nimesulide or NS-398 (5 mg/kg/day) for 3 weeks lowered high blood pressure and cardiac hypertrophy with decreased expression levels of cardiac hypertrophy markers [atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP)], Ang type 1 receptor, urotensin II, and urotensin II receptor in 2K1C rats. Plasma level of ANP was markedly increased and plasma levels of Ang II and aldosterone were decreased by treatment with nimesulide or NS-398. In both in vitro and in vivo experiments, nimesulide or NS-398 augmented ANP release in 2K1C rats. The inhibitory effect of NS-398 on blood pressure was attenuated by the pretreatment with natriuretic peptide receptor-A (NPR-A) antagonist (A71915, 30 μg/kg/day). These results suggest that chronic treatment with nimesulide or NS-398 attenuated hypertension and cardiac hypertrophy partly through ANP release in 2K1C rats.

Topics: Aldosterone; Angiotensin II; Animals; Atrial Natriuretic Factor; Blood Pressure; Cardiomegaly; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Gene Expression Regulation, Neoplastic; Humans; Hypertension, Renovascular; Natriuretic Peptide, Brain; Nitrobenzenes; Rats; Sulfonamides

Cardiomyocyte hypertrophy is an adaptive response of heart to various stress conditions. During the period of stress accumulation, transition from physiological hypertrophy to pathological hypertrophy results in the promotion of heart failure. Our previous studies found that ZAK, a sterile alpha motif and leucine zipper containing kinase, was highly expressed in infarcted human hearts and demonstrated that overexpression of ZAK induced cardiac hypertrophy. This study evaluates, cellular events associated with the expression of two doxycycline (Dox) inducible Tet-on ZAK expression systems, a Tet-on ZAK WT (wild-type), and a Tet-on ZAK DN (mutant, Dominant-negative form) in H9c2 myoblast cells; Tet-on ZAK WT was found to increase cell size and hypertrophic marker BNP in a dose-dependent manner. To ascertain the mechanism of ZAK-mediated hypertrophy, expression analysis with various inhibitors of the related upstream and downstream proteins was performed. Tet-on ZAK WT expression triggered the p38 and JNK pathway and also activated the expression and nuclear translocation of p-GATA4 and p-c-Jun transcription factors, without the involvement of p-ERK or NFATc3. However, Tet-on ZAK DN showed no effect on the p38 and JNK signaling cascade. The results showed that the inhibitors of JNK1/2 and p38 significantly suppressed ZAK-induced BNP expression. The results show the role of ZAK and/or the ZAK downstream events such as JNK and p38 phosphorylation, c-Jun, and GATA-4 nuclear translocation in cardiac hypertrophy. ZAK and/or the ZAK downstream p38, and JNK pathway could therefore be potential targets to ameliorate cardiac hypertrophy symptoms in ZAK-overexpressed patients.

Topics: Animals; Cardiomegaly; Cell Line; Cell Size; GATA4 Transcription Factor; MAP Kinase Signaling System; Myocytes, Cardiac; Natriuretic Peptide, Brain; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Protein Kinases; Proto-Oncogene Proteins c-jun; Rats; Signal Transduction; Transcription Factors

Left ventricular hypertrophy (LVH) is an independent risk factor for cardiac failure. Reduction of LVH has beneficial effects on the heart. LVH is associated with shift in energy substrate preference from fatty acid to glucose, mediated by down regulation of peroxisome proliferator-activated receptor-alpha (PPAR-α). As long-term dependence on glucose can promote adverse cardiac remodeling, it was hypothesized that, prevention of metabolic shift by averting down regulation of PPAR-α can reduce cardiac remodeling in spontaneously hypertensive rat (SHR). Cardiac response to stimulation of PPAR-α presumably depends on the type of ligand used. Therefore, the study was carried out in SHR, using two different PPAR-α ligands. SHR were treated with either fenofibrate (100 mg/kg/day) or medium-chain triglyceride (MCT) Tricaprylin (5% of diet) for 4 months. Expression of PPAR-α and medium-chain acylCoA dehydrogenase served as markers, for stimulation of PPAR-α. Both ligands stimulated PPAR-α. Decrease of blood pressure was observed only with fenofibrate. LVH was assessed from heart-weight/body weight ratio, histology and brain natriuretic peptide expression. As oxidative stress is linked with hypertrophy, serum and cardiac malondialdehyde and cardiac 3-nitrotyrosine levels were determined. Compared to untreated SHR, LVH and oxidative stress were lower on supplementation with MCT, but higher on treatment with fenofibrate. The observations indicate that reduction of blood pressure is not essentially accompanied by reduction of LVH, and that, progressive cardiac remodeling can be prevented with decrease in oxidative stress. Contrary to the notion that reactivation of PPAR-α is detrimental; the study substantiates that cardiac response to stimulation of PPAR-α is ligand specific.

Topics: Acyl-CoA Dehydrogenase; Animals; Blood Pressure; Cardiomegaly; Fenofibrate; Gene Expression; Hypertension; Ligands; Male; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Oxidative Stress; PPAR alpha; Procollagen; Rats, Inbred SHR

Intermedin (IMD), a novel member of the calcitonin/calcitonin gene-related peptide family, is involved in maintaining circulatory homeostasis and is a protective factor of heart and vessel. Here, we investigated the effects of IMD on cardiac hypertrophy in vivo and in vitro and explored the mechanisms involved.. IMD1-53 (100 ng/kg/h) was systemically administered to rats with cardiac hypertrophy induced by abdominal aortic constriction (AAC) by a mini-osmotic pump the next day after surgery continuously for 4 weeks. The AAC-treated rats before IMD infusion showed increased IMD content and expression of its receptors in the hearts. In-vivo administration of IMD1-53 greatly attenuated the cardiac hypertrophy as shown by heart weight to body weight ratio (HW/BW), haemodynamics, echocardiography, histological analyses and expression of hypertrophic markers atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) induced by AAC. IMD1-53 treatment significantly reduced the myocardial protein expression of endoplasmic reticulum stress (ERS) markers such as glucose-regulated protein 78 (GRP78), CCAAT/enhancer binding protein homologous protein (CHOP) and caspase-12, whereas the protein level of phosphorylated AMP-activated protein kinase (p-AMPK) was upregulated with IMD1-53 treatment, which was further confirmed in cultured cardiomyocytes. Concurrently, cardiomyocyte apoptosis in vivo and in vitro was ameliorated by IMD1-53 treatment. The inhibitory effects of IMD1-53 on ERS and apoptosis were eliminated on pretreatment with compound C, an AMPK inhibitor.. IMD1-53 could exert its cardioprotective effect on cardiac hypertrophy by inhibiting myocardial ERS and apoptosis, possibly via activation of AMPK signalling.

Topics: Adrenomedullin; AMP-Activated Protein Kinases; Animals; Apoptosis; Atrial Natriuretic Factor; Cardiomegaly; Caspase 12; CCAAT-Enhancer-Binding Proteins; Cells, Cultured; Echocardiography; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Heat-Shock Proteins; Male; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Neuropeptides; Organ Size; Phosphorylation; Rats

ApoE-/- mice fed a high fat and high cholesterol (HFHC) diet (20% fat and 1.25% cholesterol) from 12 weeks of age to 36 weeks revealed an age-dependent increase in the left ventricular mass (LV mass) and decline in fractional shortening (FS%), which worsened with HFHC diet. These traits are indicative of maladaptive pathological cardiac hypertrophy and dysfunction. This was accompanied by loading of glycosphingolipids and increased gene expression of ANP, BNP in myocardial tissue. Masson's trichrome staining revealed a significant increase in cardiomyocyte size and fibrosis. In contrast, treatment with 5 and 10 μM D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP), an inhibitor of glucosylceramide synthase and lactosylceramide synthase, dose-dependently decreased the load of glycosphingolipids and preserved fractional shortening and maintained left ventricular mass to normal 12-week-old control levels over a 6 month treatment period. Our mechanistic studies showed that D-PDMP inhibited cardiac hypertrophy by inhibiting the phosphorylation of mitogen-activated protein kinase (MAPK). We propose that associating increased glycosphingolipid synthesis with cardiac hypertrophy could serve as a novel approach to prevent this phenotype in experimental animal models of diet -induced atherosclerotic heart disease.

Topics: Animals; Apolipoproteins E; Atrial Natriuretic Factor; Cardiomegaly; Cardiotonic Agents; Cholesterol; Diet, High-Fat; Enzyme Inhibitors; Galactosyltransferases; Gene Expression; Glucosyltransferases; Glycosphingolipids; Heart Ventricles; Male; Mice; Mice, Knockout; Mitogen-Activated Protein Kinases; Morpholines; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phosphorylation

Carbon monoxide (CO) is one of the cytoprotective byproducts of heme oxygenase (HO)-1 and exerts anti-inflammatory action in various models. However, the detailed mechanisms underlying CO-induced HO-1 expression in primary human cardiomyocytes remain largely unidentified. We used primary left ventricle myocytes as a model and applied CO releasing molecule (CORM)-2 to investigate the relationship of CO and HO-1 expression. We herein used Western blot, real-time PCR, promoter activity and EIA to investigate the role of HO-1 expression protecting against thrombin-mediated responses. We found that thrombin-induced COX-2 expression, PGE2 release and cardiomyocyte hypertrophy markers (increase in ANF/BNP, α-actin expression and cell surface area) was attenuated by pretreatment with CORM-2 which was partially reversed by hemoglobin (Hb) or ZnPP (an inhibitor of HO-1 activity), suggesting that HO-1/CO system may be of clinical importance to ameliorate heart failure through inhibition of inflammatory responses. CORM-2-induced HO-1 protein expression, mRNA and promoter was attenuated by pretreatment with the inhibitors of Pyk2 (PF431396), PDGFR (AG1296), PI3K (LY294002), Akt (SH-5), p38 (SB202530), JNK1/2 (SP600125), FoxO1 (AS1842856) and Sp1 (mithramycin A). The involvement of these signaling components was further confirmed by transfection with respective siRNAs, consistent with those of pharmacological inhibitors. These results suggested that CORM-2-induced HO-1 expression is mediated through a Pyk2/PDGFR/PI3K/Akt/FoxO1/Sp1-dependent manner and exerts a cytoprotective effect in human cardiomyocytes.

Topics: Actins; Atrial Natriuretic Factor; Carbon Dioxide; Cardiomegaly; Cells, Cultured; Cyclooxygenase 2; Cytoprotection; Dinoprostone; Dose-Response Relationship, Drug; Enzyme Induction; Enzyme Inhibitors; Heme Oxygenase-1; Humans; Myocytes, Cardiac; Natriuretic Peptide, Brain; Organometallic Compounds; Primary Cell Culture; RNA Interference; Signal Transduction; Thrombin; Time Factors; Transfection

We investigated whether the pathways linked to Toll-like receptors 2 and 4 (TLRs) are involved in renal ischemia-reperfusion (I/R)-induced cardiac hypertrophy. Wild type (WT) C57BL/6J, TLR2-/- and TLR4-/- mice were subjected to left kidney ischemia for 60 min followed by reperfusion for 5, 8, 12 and 15 days. Proton density magnetic resonance showed alterations in the injured kidney from WT mice, together with signs of parenchymal edema and higher levels of vimentin mRNA, accompanied by: (i) small, but significant, increase in serum urea after 24 h, (ii) 100% increase in serum creatinine at 24 h. A serum peak of inflammatory cytokines occurred after 5 days of reperfusion. Heart weight/body weight and heart weight/tibia length ratios increased after 12 and 15 days of reperfusion, respectively. Cardiac hypertrophy markers, B-type natriuretic peptide (BNP) and α-actin, left ventricle mass, cardiac wall thickness and myocyte width increased after 15 days of reperfusion, together with longer QTc and action potential duration. Cardiac TLRs, MyD88, HSP60 and HSP70 mRNA levels also increased. After 15 days of reperfusion, absence of TLRs prevented cardiac hypertrophy, as reflected by similar values of left ventricular cardiac mass and heart weight/body weight ratio compared to the transgenic Sham. Renal tissular injury also ameliorated in both knockout mice, as revealed by the comparison of their vimentin mRNA levels with those found in the WT on the same day after I/R. The I/R TLR2-/- group had TNF-α, IFN-γ and IL-1β levels similar to the non-I/R group, whereas the TLR4-/- group conserved the p-NF-κB/NF- κB ratio contrasting with that found in TLR2-/-. We conclude: (i) TLRs are involved in renal I/R-induced cardiac hypertrophy; (ii) absence of TLRs prevents I/R-induced cardiac hypertrophy, despite renal lesions seeming to evolve towards those of chronic disease; (iii) TLR2 and TLR4 selectively regulate the systemic inflammatory profile and NF- κB activation.

Topics: Actins; Animals; Cardiomegaly; Chaperonin 60; Cytokines; Heart; HSP70 Heat-Shock Proteins; Ischemia; Kidney; Kidney Diseases; Mice; Mice, Inbred C57BL; Mice, Knockout; Myeloid Differentiation Factor 88; Myocardium; Natriuretic Peptide, Brain; Reperfusion Injury; Toll-Like Receptor 2; Toll-Like Receptor 4; Vimentin

To observe the effect of exercise preconditioning (EP) on pressure overload-induced pathological cardiac hypertrophy and explore related mechanisms.. Ten-week-old male Sprague-Dawley rats (n = 80) were randomly divided into four groups via random number table method: sham, TAC, EP + sham and EP + TAC. Two EP groups were subjected to 4 weeks of treadmill training, and followed by sham and TAC operations. Eight weeks after the surgery, mean arterial pressure (MAP), cardiac morphology, mRNA expressions of the B-type natriuretic peptide (BNP) and heat shock protein (HSP) 70 and protein expression of the BNP, heat shock transcription factor 1 (HSF1), HSP70, nuclear factor κB (NF-κB) p65, and interleukin-2 (IL-2) were examined.. (1) Pathological cardiac hypertrophy index: eight weeks after TAC, MAP, heart size, HW/BW, cross-sectional area of the cardiomyocytes (CSA) and mRNA and protein expressions of BNP in the LV were all significantly higher in the TAC and EP + TAC groups than respective sham groups (all P < 0.05). HW/BW, CSA, and mRNA and protein expressions of BNP in the LV were significantly lower in EP + TAC group than in TAC group (all P < 0.05). (2) mRNA and protein expressions of HSF1 and HSP70 and nuclear HSF1 levels were significantly downregulated post TAC, however, EP treatment significantly increased the expression of HSF1 and nuclear HSF1 levels in TAC rats (all P < 0.05). (3) mRNA and protein expressions of NF-κB p65 and IL-2 were significantly increased in the TAC and EP + TAC groups compared with the respective sham groups (all P < 0.05), which were significantly downregulated in EP + TAC group compared to TAC group (all P < 0.05).. EP could effectively reduce the cardiac hypertrophic responses induced by TAC possibly through upregulating the expressions of HSF1 and HSP70 and inhibiting the expression of NF-κB p65 and its nuclear translocation.

Topics: Animals; Cardiomegaly; DNA-Binding Proteins; Down-Regulation; Heat Shock Transcription Factors; HSP70 Heat-Shock Proteins; Interleukin-2; Male; Myocytes, Cardiac; Natriuretic Peptide, Brain; Physical Conditioning, Animal; Rats; Rats, Sprague-Dawley; RNA, Messenger; Signal Transduction; Transcription Factor RelA; Transcription Factors

Diabetic cardiomyopathy is a leading cause of morbidity and mortality, and Insulin2 mutant (Ins2+/-) Akita is a genetic mice model of diabetes relevant to humans. Dicer, miRNAs, and inflammatory cytokines are associated with heart failure. However, the differential expression of miRNAs, dicer, and inflammatory molecules are not clear in diabetic cardiomyopathy of Akita. We measured the levels of miRNAs, dicer, pro-inflammatory tumor necrosis factor alpha (TNFα), and anti-inflammatory interleukin 10 (IL-10) in C57BL/6J (WT) and Akita hearts. The results revealed increased heart to body weight ratio and robust expression of brain natriuretic peptide (BNP: a hypertrophy marker) suggesting cardiac hypertrophy in Akita. The multiplex RT-PCR, qPCR, and immunoblotting showed up regulation of dicer, whereas miRNA array elicited spread down regulation of miRNAs in Akita including dramatic down regulation of let-7a, miR-130, miR-142-3p, miR-148, miR-338, miR-345-3p, miR-384-3p, miR-433, miR-450, miR-451, miR-455, miR-494, miR-499, miR-500, miR-542-3p, miR-744, and miR-872. Conversely, miR-295 is induced in Akita. Cardiac TNFα is upregulated at mRNA (RT-PCR and qPCR), protein (immunoblotting), and cellular (immunohistochemistry and confocal microscopy) levels, and is robust in hypertrophic cardiomyocytes suggesting direct association of TNFα with hypertrophy. Contrary to TNFα, cardiac IL-10 is downregulated in Akita. In conclusion, induction of dicer and TNFα, and attenuation of IL-10 and majority of miRNA are associated with cardiomyopathy in Akita and could be used for putative therapeutic target for heart failure in diabetics.

Topics: Animals; Cardiomegaly; DEAD-box RNA Helicases; Diabetes Mellitus, Type 1; Gene Expression Regulation; Insulin; Interleukin-10; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; MicroRNAs; Natriuretic Peptide, Brain; Ribonuclease III; Tumor Necrosis Factor-alpha

The expression of Nppa (ANF) and Nppb (BNP) marks the chamber myocardium in the embryo, and both genes serve as early and accurate markers for hypertrophy and heart failure. Non-invasive visualization of Nppa-Nppb expression in living mice would enable to evaluate the disease state during the course of time in heart disease models. We sought to develop a method to assess the pattern and level of Nppa and Nppb expression within living mice.. A modified bacterial artificial chromosome containing a genomic segment spanning the Nppa-Nppb locus was randomly integrated into the mouse genome. Firefly Luciferase was inserted into Nppa and the red fluorescent protein gene Katushka into Nppb. Both reporters precisely recapitulated the spatio-temporal patterns of Nppa and Nppb, respectively. In a hypertrophy model (transverse aortic constriction) and myocardial infarction model (left anterior descending coronary artery occlusion), the non-invasively measured bioluminescent signal from Luciferase correlated with Nppa expression, and the intensity of red fluorescence with levels of the expression of Katushka and Nppb. After myocardial infarction, the border zone of the infarct area was readily identified by an increased intensity of Katushka fluorescence.. A genomic region sufficient to regulate the developmental pattern and stress response of Nppa and Nppb has been defined. The double reporter mice can be used for the functional imaging and investigation of cardiac hypertrophy and myocardial infarction in vivo.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Chromosomes, Artificial, Bacterial; Disease Models, Animal; Genes, Reporter; Heart Ventricles; Luminescent Proteins; Mice; Mice, Transgenic; Myocardial Infarction; Natriuretic Peptide, Brain; Up-Regulation

Endothelin-1 (ET-1) is a critical molecule that involved in heart failure. It has been proved that ET-1 stimulation results in cardiac hypertrophy both in vitro and in vivo, but the mechanisms underlying remain largely unknown. In this study, we reported that cyclooxygenase-2 (COX-2) might be an important mediator of hypertrophic responses to ET-1 stimulation. In the cultured rat neonatal cardiomyocytes, ET-1 significantly upregulated the expression and activity of COX-2, which was accompanied by increase in cell surface area and BNP mRNA level. In contrast, ET-1-dependent cardiomyocyte hypertrophy was abolished by COX-2 selective inhibitors, NS-398 and celecoxib, or by COX-2 RNA interference, but the inhibitory effects could be diminished by pretreatment with PGE2. Furthermore, cyclosporin A (CsA) and knockdown of nuclear factor of activated T-cells c3 (NFATc3) inhibited the expression of COX-2 induced by ET-1, and NFATc3 could also bound to the -GGAAA- sequence in the promoter region of rat COX-2 gene, indicating that calcineurin/NFATc3 signaling participated in the transcriptional regulation of COX-2 following ET-1 treatment. These findings provided further insight into the roles of ET-1 in cardiac hypertrophy and suggested a potential therapeutic strategy against cardiac hypertrophy by inhibiting COX-2.

Topics: Animals; Animals, Newborn; Calcineurin; Cardiomegaly; Celecoxib; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclosporine; Dinoprostone; Endothelin-1; Gene Expression Regulation; Myocytes, Cardiac; Natriuretic Peptide, Brain; NFATC Transcription Factors; Nitrobenzenes; Primary Cell Culture; Promoter Regions, Genetic; Protein Binding; Pyrazoles; Rats; Rats, Sprague-Dawley; RNA, Messenger; RNA, Small Interfering; Signal Transduction; Sulfonamides; Transcription, Genetic

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Genes, Reporter; Myocardial Infarction; Natriuretic Peptide, Brain

Astragaloside IV is widely used for the treatment of cardiovascular diseases in China. However, its role in cardiac hypertrophy remains unclear. In this study, we aim to determine the protective effects of astragaloside IV on myocardial hypertrophy induced by lipopolysaccharide and to identify their precise molecular and cellular mechanisms. Cell size, reorganization of actin filaments, and ANP and BNP mRNA expression were used as indices of hypertrophy; CaN and GATA-4 expression and the distribution of NFAT-3 in both cytoplasm and nucleus were determined by Western blot analysis; Ca2+ transient in Fura-2/AM-loaded cells was measured by Till image system. Our data demonstrated that lipopolysaccharide challenge induced cardiac hypertrophy, increased resting Ca2+ transient level, promoted activation of CaN and GATA-4, and enhanced nuclear translocation of NFAT-3. Administration of astragaloside IV (16, 32, and 64 µM) 1 h prior to lipopolysaccharide stimulation dose-dependently attenuated cardiac hypertrophy induced by lipopolysaccharide. Further studies demonstrated that astragaloside IV inhibited the increment of the resting intracellular free Ca2+, and its effect was similar to verapamil. Moreover, astragaloside IV also inhibited the activation of CaN and GATA-4, and the nuclear translocation of NFAT-3 induced by lipopolysaccharide. In conclusion, our results revealed that astragaloside IV had the potential to protect against cardiac hypertrophy through Ca2+-mediated CaN signaling pathways.

Topics: Animals; Atrial Natriuretic Factor; Calcineurin; Calcium Signaling; Cardiomegaly; Cardiotonic Agents; Cells, Cultured; Drugs, Chinese Herbal; Lipopolysaccharides; Myocytes, Cardiac; Natriuretic Peptide, Brain; NFATC Transcription Factors; Rats; Saponins; Signal Transduction; Triterpenes

Mercury exposure is associated with increased risk of cardiovascular disease and profound cardiotoxicity. However, the correlation between Hg(2+)-mediated toxicity and alteration in cardiac cytochrome P450s (Cyp) and their dependent arachidonic acid metabolites has never been investigated. Therefore, we investigated the effect of acute mercury toxicity on the expression of Cyp-epoxygenases and Cyp-ω-hydroxylases and their associated arachidonic acid metabolites in mice hearts. In addition, we examined the expression and activity of soluble epoxide hydrolase (sEH) as a key player in arachidonic acid metabolism pathway. Mercury toxicity was induced by a single intraperitoneal injection (IP) of 2.5 mg/kg of mercuric chloride (HgCl₂). Our results showed that mercury treatment caused a significant induction of the cardiac hypertrophy markers, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP); in addition to Cyp1a1, Cyp1b1, Cyp2b9, Cyp2b10, Cyp2b19, Cyp2c29, Cyp2c38, Cyp4a10, Cyp4a12, Cyp4a14, Cyp4f13, Cyp4f15, Cyp4f16 and Cyp4f18 gene expression. Moreover, Hg(2+) significantly increased sEH protein expression and activity levels in hearts of mercury-treated mice, with a consequent decrease in 14,15-, and 11,12-epoxyeicosatrienoic acids (EETs) levels. Whereas the formation of 14,15-, 11,12-, 8,9-dihydroxyeicosatrienoic acids (DHETs) was significantly increased. In conclusion, acute Hg(2+) toxicity modulates the expression of several Cyp and sEH enzymes with a consequent decrease in the cardioprotective EETs which could represent a novel mechanism by which mercury causes progressive cardiotoxicity. Furthermore, inhibiting sEH might represent a novel therapeutic approach to prevent Hg(2+)-induced hypertrophy.

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Arachidonic Acid; Atrial Natriuretic Factor; Biomarkers; Cardiomegaly; Cytochrome P-450 Enzyme System; Epoxide Hydrolases; Gene Expression Regulation, Enzymologic; Heart; Injections, Intraperitoneal; Isoenzymes; Male; Mercuric Chloride; Mice; Mice, Inbred C57BL; Myocardium; Natriuretic Peptide, Brain; RNA, Messenger

Cardiomyocyte hypertrophy is an adaptive response of the heart to various types of stress. During the period of stress accumulation, the transition from physiological hypertrophy to pathological hypertrophy results in the promotion of heart failure. Gelsolin (GSN) is a member of the actin-binding proteins, which regulate dynamic actin filament organization by severing and capping. Moreover, GSN also regulates cell morphology, differentiation, movement, and apoptosis. In this study, we used H9c2 and H9c2-GSN stable clones in an attempt to understand the mechanisms of GSN overexpression in cardiomyocytes. These data showed that the overexpression of GSN in H9c2-induced cardiac hypertrophy and increased the pathological hypertrophy markers atrial natriuretic peptide brain natriuretic peptide. Furthermore, we found that E-cadherin expression decreased with the overexpression of GSN in H9c2, but β-catenin expression increased. These data presume that the cytoskeleton is loose. Further, previous studies show that the mitogen-activated protein kinase pathway can induce cardiac hypertrophy. Our data showed that p-p38 expression increased with the overexpression of GSN in H9c2, and the transcription factor p-GATA4 expression also increased, suggesting that the overexpression of GSN in H9c2-induced cardiac hypertrophy seemed to be regulated by the p38/GATA4 pathway. Moreover, we used both the p38 inhibitor (SB203580) and GSN siRNA to confirm our conjecture. We found that both of these factors significantly suppressed gelsolin-induced cardiac hypertrophy through p38/GATA4 signaling pathway. Therefore, we predict that the gene silencing of GSN and/or the downstream blocking of GSN along the p38 pathway could be applied to ameliorate pathological cardiac hypertrophy in the future.

Topics: Cardiomegaly; DNA-Binding Proteins; GATA4 Transcription Factor; Gelsolin; Gene Expression Regulation; Humans; Hypertrophy; Myocytes, Cardiac; Natriuretic Peptide, Brain; p38 Mitogen-Activated Protein Kinases; Promoter Regions, Genetic; Signal Transduction; Transcriptional Activation

Pharmacological blockade of the mineralocorticoid receptor (MR) ameliorates end-organ damage in chronic heart failure. However, the clinical use of available steroidal MR antagonists is restricted because of concomitant hyperkalemia especially in patients with diminished kidney function. We have recently identified a novel nonsteroidal MR antagonist, finerenone, which uniquely combines potency and selectivity toward MR. Here, we investigated the tissue distribution and chronic cardiorenal end-organ protection of finerenone in comparison to the steroidal MR antagonist, eplerenone, in 2 different preclinical rat disease models. Quantitative whole-body autoradiography revealed that [C]-labeled finerenone equally distributes into rat cardiac and renal tissues. Finerenone treatment prevented deoxycorticosterone acetate-/salt-challenged rats from functional as well as structural heart and kidney damage at dosages not reducing systemic blood pressure. Finerenone reduced cardiac hypertrophy, plasma prohormone of brain natriuretic peptide, and proteinuria more efficiently than eplerenone when comparing equinatriuretic doses. In rats that developed chronic heart failure after coronary artery ligation, finerenone (1 mg·kg·d), but not eplerenone (100 mg·kg·d) improved systolic and diastolic left ventricular function and reduced plasma prohormone of brain natriuretic peptide levels. We conclude that finerenone may offer end-organ protection with a reduced risk of electrolyte disturbances.

Topics: Animals; Autoradiography; Cardiomegaly; Disease Models, Animal; Eplerenone; Heart Failure; Kidney Diseases; Male; Mineralocorticoid Receptor Antagonists; Naphthyridines; Natriuretic Peptide, Brain; Peptide Fragments; Rats; Rats, Sprague-Dawley; Rats, Wistar; Spironolactone; Tissue Distribution

Mitogen-activated protein kinases (MAPKs) are involved in the regulation of cardiac hypertrophy and myocyte survival. Extracellular signal regulated protein kinase 1 and 2 (ERK1/2) are key components in the MAPK signaling pathways. Dysfunction of ERK1/2 in congenital heart diseases (Noonan syndrome and LEOPARD syndrome) leads to cardiac hypertrophy. ERK2 contributes 70% of protein content to total ERK1/2 content in myocardium; however, the specific role of ERK2 in regulating cardiac hypertrophy is yet to be further defined. To investigate the specific role of ERK2 played in the cardiomyocytes, we generated and examined mice with cardiomyocyte-specific deletion of the erk2 gene (ERK2(cko) mice). Following short-term pathological hypertrophic stresses, the mutant mice showed attenuated hypertrophic remodeling characterized by a blunted increase in the cross-sectional area of individual myocytes, downregulation of hypertrophic foetal gene markers (ANP and BNP), and less interstitial fibrosis. However, increased cardiomyocyte apoptosis was observed. Upon prolonged stimulation, ERK2(cko) mice developed deterioration in cardiac function. However, absence of ERK2 did not affect physiological hypertrophy induced by 4weeks of swimming exercise. These results revealed an essential role for ERK2 in cardiomyocytes in the development of pathological hypertrophic remodeling and resistance to cell death.

Topics: Animals; Apoptosis; Atrial Natriuretic Factor; Cardiomegaly; Fibrosis; Gene Expression Regulation; Male; Mice; Mice, Knockout; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Primary Cell Culture; Stress, Physiological; Swimming

The objective of this study was to compare the levels of fetal serum cardiac troponin T (cTnT), representing cardiac injury, and N-terminal pro-B-type natriuretic peptide (nt-proBNP), representing cardiac volume overload, between fetuses affected and not affected by hemoglobin (Hb) Bart's disease, as well as between anemic and nonanemic fetuses.. One hundred fourteen pregnancies at risk for fetal Hb Bart's disease scheduled for cordocentesis at 18 to 22 weeks were recruited into the study. Fetal blood was collected to test for cTnT, nt-proBNP and Hb levels as well as Hb typing.. Serum nt-proBNP was significantly higher in Hb Bart's fetuses (24 cases) than in unaffected fetuses (63 cases), whereas cTnT was significantly lower in the affected group than in the unaffected group. The serum nt-proBNP levels significantly increased with the degree of fetal anemia; cTnT levels decreased in fetuses with high degree of anemia.. At mid-pregnancy, nt-proBNP was significantly higher in fetuses with Hb Bart's disease than in nonanemic fetuses; cTnT was significantly lower in anemic than in normal fetuses. This study suggests that cardiomegaly from fetal anemia in early gestation is not associated with fetal cardiac injury or myocardial dysfunction but presents as cardiac volume overload from a compensatory process to maintain adequate tissue oxygenation.

Topics: Adult; Anemia; Biomarkers; Cardiac Volume; Cardiomegaly; Case-Control Studies; Cordocentesis; Female; Fetal Diseases; Hemoglobinopathies; Hemoglobins, Abnormal; Humans; Natriuretic Peptide, Brain; Peptide Fragments; Pregnancy; Pregnancy Trimester, Second; Troponin T

Obesity is often associated with the development of cardiac hypertrophy but the hypertrophy-related pathways in obesity remain unknown. The purpose of this study was to evaluate cardiac hypertrophy-related markers, atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), tumor necrosis factor-alpha (TNFα) and hypertrophy-related pathways, interleukin (IL)-6-STAT3, IL-6-MEK5-ERK5 and calcineurin-nuclear factor of activated T-cells (NFAT)3 in the excised hearts from obese rats. Twelve obese Zucker rats were studied at 5-6 months of age and twelve age-matched lean Zucker rats served as the control group. The cardiac characteristics, myocardial architecture, ANP, BNP, TNFα levels, IL-6, STAT3, p-STAT3, MEK5, ERK-5, p-ERK-5, calcineurin and NFAT3 in the left ventricle from the rats were measured by heart weight index, echocardiography, vertical cross section, histological analysis, reverse transcription polymerase chain reaction and western blotting. Compared with the lean control, the whole heart weight, the left ventricule weight, the ratio of the whole heart weight to tibia length, echocardiographic interventricular septum, left ventricular posterior wall thickness, myocardial morphological changes and systolic blood pressure were found to increase in the obese rats. The protein levels of ANP, BNP, TNFα, IL-6, STAT3, p-STAT3, MEK-5, ERK-5, p-ERK 5, calcineurin and NFAT3 were also significantly increased in the hearts of the obese rats. The results showed that the hypertrophy-related markers, ANP, BNP and TNFα, the hypertrophy-related pathways IL-6-STAT3 and IL-6-MEK5-ERK5, and the calcineurin-NFAT3 hypertrophy-related pathways were more active in obese Zucker rats, which may provide possible hypertrophic mechanisms for developing cardiac hypertrophy and pathological changes in obesity.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Disease Models, Animal; Interleukin-6; Male; MAP Kinase Kinase 5; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase 7; Natriuretic Peptide, Brain; Obesity, Morbid; Rats, Zucker; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; STAT3 Transcription Factor; Tumor Necrosis Factor-alpha

Cardiac hypertrophy is a major cause of morbidity and mortality worldwide. Transforming growth factor-β1 (TGF-β1) signaling has been considered as a trigger causally contributing to pathological cardiac hypertrophy. Asiatic acid (AA) is a triterpenoid compound extracted from Centella asiatica and exhibits a variety of pharmacological effects. In this study, we investigated the anti-hypertrophic effects and mechanisms of action of AA in a TGF-β1-stimulated hypertrophic response using cultured neonatal cardiomyocytes in vitro and in a mouse model of cardiac hypertrophy induced by pressure overload in vivo. Treatment with AA markedly attenuated the TGF-β1-induced hypertrophic responses of cardiomyocytes as reflected by reduction in the cardiomyocyte surface area and the inhibition of atrial natriuretic peptide (ANP) mRNA expression. The protective effects of AA on hypertrophic cardiomyocytes were associated with the blocking of p38 and extracellular signal‑regulated kinase (ERK)1/2 phosphorylation and the reduction of nuclear factor-κB (NF-κB) binding activity. In vivo experiments indicated that the administration of AA prevented cardiac hypertrophy and dysfunction induced by pressure overload. It was found that AA markedly reduced the excessive production of TGF-β1 in the hypertrophic myocardium, blocked the phosphorylation of p38 and ERK1/2 and inhibited the activation of NF-κB. Our data suggest that AA may be a novel therapeutic agent for cardiac hypertrophy. The inhibition of TGF-β1‑mediated hypertrophic signaling may be the mechanism through which AA prevents cardiac hypertrophy.

Topics: Animals; Cardiomegaly; Centella; Humans; In Vitro Techniques; MAP Kinase Signaling System; Mice; Myocytes, Cardiac; Natriuretic Peptide, Brain; Pentacyclic Triterpenes; Phosphorylation; RNA, Messenger; Transforming Growth Factor beta1

The precise molecular mechanisms leading to disturbance of Ca(2+)/calmodulin-dependent intracellular signalling in cardiac hypertrophy remains unclear. As an endogenous calmodulin regulator protein, the pathophysiology role of PEP-19 during cardiac hypertrophy was investigated in the present study. We here demonstrated that PEP-19 protein levels are significantly elevated in the aortic banding model in vivo and angiotensin II-induced cardiomyocyte hypertrophy in vitro. Consistent with inhibitory actions of PEP-19 on cardiomyocyte hypertrophy, induction of CaMKII and calcineurin activation as well as hypertrophy-related genes including atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) was significantly inhibited by PEP-19 transfection. Moreover, PEP-19 partially ameliorates angiotensin II-induced elevation of phospho-phospholamban (Thr-17) and sarcoplasmic reticulum Ca(2+) release in cardiomyocytes. Together, our results suggest that PEP-19 attenuates angiotensin II-induced cardiomyocyte hypertrophy via suppressing the disturbance of CaMKII and calcineurin signaling.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Calcineurin; Calcium; Calcium Signaling; Calcium-Binding Proteins; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Calmodulin; Calmodulin-Binding Proteins; Cardiomegaly; Cells, Cultured; Gene Expression; Hypertrophy; Male; Myocytes, Cardiac; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Rats, Sprague-Dawley; Sarcoplasmic Reticulum

Estimating fluid balance in haemodialysis patients is essential when determining dry weight, but limited methods are currently available. B-type natriuretic peptide (BNP) is a useful surrogate marker in patients with congestive heart failure (CHF), but whether its validity could be generalized to haemodialysis patients has not been studied well.. A total of 457 haemodialysis patients at a dialysis centre were analyzed. Determinants of BNP were assessed in connection with ultrasound cardiography (UCG) records, Kt/V, ultrafiltration rate (UFR), and demographic factors. All-cause death and cardiovascular (CV) events were recorded as the main outcome.. Among the UCG records, left atrial diameter (LAD), left ventricular ejection fraction (LVEF), were determinants of log-transformed (ln) BNP; UFR, age and sex were also significant. There was a positive correlation between BNP and LAD (r = 0.285, P < 0.001). Receiver operating characteristic (ROC) analysis revealed that BNP had 90% and 80% sensitivity to predict the presence of LA enlargement of 77.9 pg/mL and 133.2 pg/mL, respectively. Higher BNP and lower LVEF were associated with higher risk for developing all-cause death and CVD. In the adjusted model, patients with BNP higher than 471 pg/mL had hazard ratio of 2.18 (95% confidence interval (CI) 1.20-3.96, P = 0.01), compared to those with BNP <109 pg/mL.. B-type natriuretic peptide was determined by LAD, LVEF, UFR, age and sex. BNP and LAD had positive correlation and BNP could become a useful tool for estimating the presence of LA enlargement. BNP and LVEF was a strong risk factor for predicting all-cause death and CV events among patients undergoing haemodialysis.

Topics: Age Factors; Aged; Area Under Curve; Biomarkers; Cardiomegaly; Cause of Death; Female; Heart Atria; Humans; Japan; Male; Middle Aged; Natriuretic Peptide, Brain; Predictive Value of Tests; Renal Dialysis; Renal Insufficiency, Chronic; Risk Assessment; Risk Factors; ROC Curve; Sex Factors; Stroke Volume; Treatment Outcome; Ultrasonography; Ventricular Function, Left; Water-Electrolyte Balance

Endothelial dysfunction can lead to congestive heart failure and the activation of endothelial ATP-sensitive potassium (K(ATP)) channels may contribute to endothelial protection. Therefore, the present study was carried out to investigate the hypothesis that natakalim, a novel K(ATP) channel opener, ameliorates post-infarction left ventricular remodeling and failure by correcting endothelial dysfunction. The effects of myocardial infarction were assessed 8 weeks following left anterior descending coronary artery occlusion in male Wistar rats. Depressed blood pressure, cardiac dysfunction, evidence of left ventricular remodeling and congestive heart failure were observed in the rats with myocardial infarction. Treatment with natakalim at daily oral doses of 1, 3 or 9 mg/kg/day for 8 weeks prevented these changes. Natakalim also prevented the progression to cardiac failure, which was demonstrated by the increase in right ventricular weight/body weight (RVW/BW) and relative lung weight, signs of cardiac dysfunction, as well as the overexpression of atrial and brain natriuretic peptide mRNAs. Our results also demonstrated that natakalim enhanced the downregulation of endothelium-derived nitric oxide, attenuated the upregulation of inducible nitric oxide synthase-derived nitric oxide (NO), inhibited the upregulated endothelin system and corrected the imbalance between prostacyclin and thromboxane A(2). Overall, our findings suggest that natakalim prevents post-infarction hypertrophy and cardiac failure by restoring the coordinated balance between endothelial function and cardiac hypertrophy.

Topics: Administration, Oral; Allyl Compounds; Animals; Blood Pressure; Cardiomegaly; Dose-Response Relationship, Drug; Endothelins; Endothelium, Vascular; Epoprostenol; Heart Failure; Heart Ventricles; Hydroxyproline; Immunohistochemistry; Male; Microscopy, Electron, Transmission; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain; Nitric Oxide; Propylamines; Rats; Rats, Wistar; Thromboxane A2; Ventricular Remodeling

Pressure overload induces cardiac hypertrophy through activation of Janus kinase 2 (Jak2), however, the underlying mechanisms remain largely unknown. In the current study, we tested whether histone deacetylase 2 (HDAC2) was involved in the process. We found that angiotensin II (Ang-II)-induced re-expression of fetal genes (Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP)) in cultured cardiomyocytes was prevented by the Jak2 inhibitor AG-490 and HDAC2 inhibitor Trichostatin-A (TSA), or by Jak2/HDAC2 siRNA knockdown. On the other hand, myocardial cells with Jak2 or HDAC2 over-expression were hyper-sensitive to Ang-II. In vivo, pressure overload by transverse aorta binding (AB) induced a significant cardiac hypertrophic response as well as re-expression of ANP and BNP in mice heart, which were markedly reduced by AG-490 and TSA. Significantly, AG-490, the Jak2 inhibitor, largely suppressed pressure overload-/Ang-II-induced HDAC2 nuclear exportation in vivo and in vitro. Meanwhile, TSA or HDAC2 siRNA knockdown reduced Ang-II-induced ANP/BNP expression in Jak2 over-expressed H9c2 cardiomyocytes. Together, these results suggest that HDAC2 might be a downstream effector of Jak2 to mediate cardiac hypertrophic response by pressure overload or Ang-II.

Topics: Active Transport, Cell Nucleus; Angiotensin II; Animals; Atrial Natriuretic Factor; Cardiomegaly; Cell Nucleus; Cells, Cultured; Histone Deacetylase 2; Hydroxamic Acids; Janus Kinase 2; Male; Mice, Inbred C57BL; Myocytes, Cardiac; Natriuretic Peptide, Brain; Peptide Fragments; Pressure; Rats; Signal Transduction; Tyrphostins

Topics: Acute Disease; Atrial Fibrillation; Cardiomegaly; Diabetes Mellitus, Type 2; Diuretics; Heart Failure; Hemorrhage; Humans; Hydrostatic Pressure; Hypertension; Leukocytosis; Lung Diseases; Lung Diseases, Interstitial; Male; Middle Aged; Natriuretic Peptide, Brain; Pulmonary Edema; Sleep Apnea Syndromes; Smoking; Tomography, X-Ray Computed; Ultrasonography

miRNAs play an important role in the pathogenesis of cardiac hypertrophy and dysfunction. However, little is known about how miR-30a regulates cardiomyocyte hypertrophy. In the study, Male C57BL/6 mice were subjected to thoracic aortic constriction, and hearts were harvested at 3 weeks. We assayed miR-30a expression level by real-time PCR and defined the molecular mechanisms of miR-30a-mediated cardiomyocyte hypertrophy. We found that myocardial expression of miR-30a was decreased in mouse models of hypertrophy and in H9c2 cells treated with phenylephrine. MiR-30a inhibition markedly increased mRNA expression of cardiac hypertrophy markers such as atrial natriuretic factor and brain natriuretic peptide in H9c2, and cell size was increased after miR-30a inhibitor treatment. Downregulated miR-30a activated autophagy by inhibiting beclin-1 expression in H9c2 cell. More important, autophagy inhibition suppressed miR-30a inhibitor-induced cardiomyocyte hypertrophy. Together, our data demonstrated that downregulated miR-30a aggravates pressure overload-induced cardiomyocyte hypertrophy by activating autophagy, thus offering a new target for the therapy of cardiomyocyte hypertrophy.

Topics: 3' Untranslated Regions; Animals; Atrial Natriuretic Factor; Autophagy; Cardiomegaly; Cell Line; Cell Size; Down-Regulation; Gene Expression Regulation; HEK293 Cells; Humans; Hypertension; Male; Mice; Mice, Inbred C57BL; MicroRNAs; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats

Topics: Amyloid Neuropathies, Familial; Cardiomegaly; Female; Heart Failure; Humans; Male; Natriuretic Peptide, Brain; Peptide Fragments; Ultrasonography

Growing evidence shows that microRNAs (miRNAs) are involved in various cardiac processes including cardiac hypertrophy. However, the modulation of miRNA by pharmacological intervention in cardiomyocyte hypertrophy has not been disclosed yet. methods: We constructed neonatal rat cardiomyocyte hypertrophy induced by angiotensin II stimulation and subjected to cardiomyocyte immunochemistry, qRT-PCR and immunoblotting analysis. In addition, we constructed the mouse cardiac hypertrophy using angomir-22 stimulation and demonstrated the potential antihypertrophic mechnism of atorvastatin.. The results showed that a collection of miRNAs were aberrantly expressed in hypertrophic cardiomyocytes induced by angiotensin II stimulation. In addition, overexpression of miR-22 was found in angiotensin II-induced hypertrophic cardiomyocytes, whereas administration of atorvastatin could reverse the upregulation of miRNA-22 nearly back to the control level. Furthermore, up-regulation of miRNA-22 in cardiomyocytes in vitro and in vivo could induce cardiac hypertrophy, which could suppress the protein level of phosphatase and tensin homolog deleted on chromosome ten (PTEN). Concomitantly, the production of ANP, BNP and β-MHC was enhanced and cardiomyocyte size was increased. However, atorvastatin could markedly knockdown miRNA-22 expression and reverse these changes in cardiomyocytes. These results suggest that the contribution of atrovastatin to cardiomyocyte hypertrophy may be involved in downregulation of miRNA-22 expression, which modulates the activity of PTEN in cardiomyocyte hypertrophy. conclusion: This study demonstrates for the first time the modulation of miRNA-22 can be achieved by pharmacological intervention. The data generated from this study provides a rationale for the development of miRNA-based strategies for antihypertrophic treatment.

Topics: Angiotensin II; Animals; Anticholesteremic Agents; Atorvastatin; Atrial Natriuretic Factor; Cardiomegaly; Cells, Cultured; Disease Models, Animal; Down-Regulation; Heptanoic Acids; Male; Mice; MicroRNAs; Myocardium; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Oligonucleotides, Antisense; Phosphoric Monoester Hydrolases; PTEN Phosphohydrolase; Pyrroles; Rats

We have previously shown that isoprenaline-induced cardiac hypertrophy causes significant changes in the expression of cytochromes P450 (CYP) and soluble epoxide hydrolase (sEH) genes. Therefore, it is important to examine whether the inhibition of sEH by 1-(1-methanesulfonyl-piperidin-4-yl)-3-(4-trifluoromethoxy-phenyl)-urea (TUPS) will protect against isoprenaline-induced cardiac hypertrophy.. Male Sprague-Dawley rats were treated with TUPS (0.65 mg kg(-1) day(-1), p.o.), isoprenaline (5 mg kg(-1) day(-1), i.p.) or the combination of both. In vitro H9c2 cells were treated with isoprenaline (100 μM) in the presence and absence of either TUPS (1 μM) or 11,12 EET (1 μM). The expression of hypertrophic, fibrotic markers and different CYP genes were determined by real-time PCR.. Isoprenaline significantly induced the hypertrophic, fibrotic markers as well as the heart to body weight ratio, which was significantly reversed by TUPS. Isoprenaline also caused an induction of CYP1A1, CYP1B1, CYP2B1, CYP2B2, CYP4A3 and CYP4F4 gene expression and TUPS significantly inhibited this isoprenaline-mediated effect. Moreover, isoprenaline significantly reduced 5,6-, 8,9-, 11,12- and 14,15-EET and increased their corresponding 8,9-, 11,12- and 14,15-dihydroxyeicosatrienoic acid (DHET) and the 20-HETE metabolites. TUPS abolished these isoprenaline-mediated changes in arachidonic acid (AA) metabolites. In H9c2 cells, isoprenaline caused a significant induction of ANP, BNP and EPHX2 mRNA levels. Both TUPS and 11,12-EET significantly decreased this isoprenaline-mediated induction of ANP, BNP and EPHX2.. TUPS partially protects against isoprenaline-induced cardiac hypertrophy, which confirms the role of sEH and CYP enzymes in the development of cardiac hypertrophy.

Topics: Animals; Atrial Natriuretic Factor; Body Weight; Cardiomegaly; Cardiotonic Agents; Cell Line; Cytochrome P-450 Enzyme System; Drug Antagonism; Epoxide Hydrolases; Gene Expression Regulation; Heart; Humans; Isoproterenol; Kidney; Liver; Natriuretic Peptide, Brain; Phenylurea Compounds; Piperidines; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction

Heart failure is becoming a global epidemic. It exerts a staggering toll on quality of life, and substantial medical and economic impact. In a pre-clinical model of cardiac hypertrophy and heart failure, we were able to overcome loss of heart function by administering the TRPV1 antagonist BCTC (4-(3-Chloro-2-pyridinyl)-N-[4-(1,1-dimethylethyl)phenyl]-1-piperazinecarboxamide). The results presented here identify TRPV1 antagonists as new treatment options for cardiac hypertrophy and heart failure.

Topics: Animals; Apoptosis; Cardiomegaly; Disease Models, Animal; Heart Failure; Humans; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Natriuretic Peptide, Brain; Pyrazines; Pyridines; TRPV Cation Channels

Farnesyl pyrophosphate synthase (FPPS), as a key branchpoint of the mevalonate pathway, catalyzes the synthesis of isoprenoid intermediates. The isoprenoid intermediates are needed for protein isoprenylation to participate in cardiac remodeling. We have previously demonstrated that both knockdown of FPPS with small interfering RNA and inhibition of FPPS by alendronate could prevent Ang II-induced hypertrophy in cultured cardiomyocytes. In this study, we evaluated the effects of FPPS inhibition in Ang II-mediated cardiac hypertrophy and fibrosis in vivo. Wild type mice were separately treated with saline, Ang II (2.88 mg/kg per day), FPPS inhibitor alendronate (0.1 mg/kg per day), or the combination of Ang II (2.88 mg/kg per day) and alendronate (0.1 mg/kg per day) for 4 weeks. The results showed that Ang II increased FPPS expression, and the increases of Ang II-induced synthesis of the isoprenoid intermediates, FPP and GGPP, were significantly inhibited by FPPS inhibitor. In the meantime, FPPS inhibition attenuated Ang II-mediated cardiac hypertrophy and fibrosis as indexed by the heart weight to body weight ratio, echocardiographic parameters, histological examinations and expression of ANP and BNP mRNA. Furthermore, it was also found that FPPS inhibitor attenuated Ang II-induced increases of RhoA activity and p-38 MAPK phosphorylation and TGF-β1 mRNA expression. In conclusion, FPPS might play an important role in Ang II-induced cardiac hypertrophy and fibrosis in vivo, at least in part through RhoA, p-38 MAPK and TGF-β1.

Topics: Alendronate; Angiotensin II; Animals; Atrial Natriuretic Factor; Cardiomegaly; Contraindications; Fibrosis; Gene Expression Regulation; Geranyltranstransferase; Humans; Male; Mice; Myocytes, Cardiac; Natriuretic Peptide, Brain; p38 Mitogen-Activated Protein Kinases; rho GTP-Binding Proteins; rhoA GTP-Binding Protein; Signal Transduction; Terpenes; Transforming Growth Factor beta1

To characterize patients with cardiac amyloidosis using echocardiography, electrocardiogram (ECG) and right heart catheterization (RHC).. Fourteen patients with biopsy verified light chain or transthyretin cardiac amyloidosis were included. All patients had heart failure with markedly elevated NT-proBNP. Echocardiography demonstrated biventricular hypertrophy, left atrial enlargement and normal to slightly reduced left ventricular ejection fraction. Tissue Doppler septal é was low and median E/é was high. Within 6 months RHC was performed in eight of the patients. The restrictive filling pattern demonstrated by echocardiography corresponded well to median pulmonary wedge pressure (21 mmHg). Systolic pulmonary artery pressure (SPAP) was increased, whereas cardiac output and stroke volume were seen to be decreased with both methods. ECG demonstrated: low voltage (36%), abnormal R-progression (65%), ST-T abnormalities (71%) and high incidence of fibrillation (36%). In addition, a case report following the treatment of melphalan and dexamethasone is presented with improvement of hypertrophy, SPAP, left ventricular mass and é.. These findings should lead to a suspicion of cardiac amyloidosis and suggest further investigation.

Topics: Aged; Aged, 80 and over; Amyloid Neuropathies, Familial; Cardiac Catheterization; Cardiomegaly; Dexamethasone; Echocardiography, Doppler; Electrocardiography; Female; Heart Failure; Humans; Male; Melphalan; Middle Aged; Natriuretic Peptide, Brain; Peptide Fragments; Pulmonary Wedge Pressure; Stroke Volume; Ventricular Function, Left

Topics: Cardiomegaly; Cholagogues and Choleretics; Dehydrocholic Acid; Heart Failure; Humans; Natriuretic Peptide, Brain; Risk Assessment; Ventricular Premature Complexes

Augmented endothelial nitric oxide (NO) synthase (eNOS) signaling has been reported to be associated with improvements in cardiac remodeling, and NO levels have been shown to be related to cardiac hypertrophy and heart failure. Imperatorin, a dietary furanocoumarin, has been shown to prevent cardiac hypertrophy in the spontaneous hypertension rats (SHR). Thus, we aimed to clarify whether imperatorin attenuates both cardiac hypertrophy and heart failure via the NO-signaling pathway. In neonatal mouse cardiac myocytes, imperatorin inhibited protein synthesis stimulated by either isoproterenol or phenylephrine, which was unchanged by NG-nitro-L-arginine methyl ester (L-NAME). Four weeks after transverse aortic constriction (TAC) on Kunming (KM) male mice, the ratio of heart weight to body weight was lower after imperatorin treatment than in controls (6.60 ± 0.35 mg/g in TAC, 4.54 ± 0.29 mg/g with imperatorin 15 mg kg(-1)d(-1), ig, P<0.01); similar changes in the ratio of lung weight to body weight (7.30 ± 0.85 mg/g in TAC, 5.42 ± 0.51 mg/g with imperatorin 15 mg kg(-1)d(-1), ig) and the myocardial fibrosis. All of these improvements were blunted by L-NAME. Imperatorin treatment significantly activated phosphorylation of eNOS. Myocardial mRNA levels of natriuretic peptide precursor type B and protein inhibitor of NO synthase, which were increased in the TAC mice, were decreased in the imperatorin-treated ones. Imperatorin can attenuate cardiac hypertrophy both in vivo and in vitro, and halt the process leading from hypertrophy to heart failure by a NO-mediated pathway.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Cells, Cultured; Cytoplasmic Dyneins; Furocoumarins; Gene Expression Regulation; Heart Failure; Male; Mice; Myocytes, Cardiac; Natriuretic Peptide, Brain; Nitric Oxide; Nitric Oxide Synthase Type III; Rats; Sarcoplasmic Reticulum Calcium-Transporting ATPases

The aim of the present study was non-invasive evaluation of the cardiovascular system in asymptomatic young adult patients with juvenile localized scleroderma (JLS) and juvenile systemic sclerosis (JSS).. A group of 34 consecutive children with scleroderma were prospectively observed in the study. The control group (CG) consisted of 20 healthy subjects. In each subject 12-lead electrocardiographic, echocardiographic, ECG Holter, and ambulatory blood pressure monitoring examinations were performed at the baseline visit and after 10 years. Additionally, B-type natriuretic peptide (BNP) concentrations were measured after 10 years.. Examinations were performed in 13 patients with JLS and 15 with JSS at the final visit. Two children had died (one from each group). Four patients were alive but refused the final visit. After 10 years, a higher prevalence of ventricular extrasystoles (p = 0.01) and an elevated pulmonary arterial pressure (JLS: p = 0.04, JSS: p = 0.03) were observed in both groups, but in comparison with the controls there was no significant difference at the final visit. In JLS patients more cases of left ventricle diastolic dysfunction, hypertension, and sinus tachycardia were diagnosed at the final visit (p ≤ 0.05). More atrioventricular block episodes in both groups of scleroderma patients were observed. Over the 10 years, arterial hypertension was diagnosed in three patients from the JLS group and in two with JSS. There were no significant differences in BNP concentrations at the final visit.. The results of the present study show that juvenile scleroderma seems to be more benign than adult-onset disease. This observational study shows subclinical, not severe, cardiac abnormalities in adult patients with juvenile-onset disease.

Topics: Adolescent; Adult; Asymptomatic Diseases; Blood Pressure; Cardiomegaly; Case-Control Studies; Child; Echocardiography; Electrocardiography; Female; Follow-Up Studies; Heart Diseases; Heart Valve Diseases; Humans; Male; Natriuretic Peptide, Brain; Prospective Studies; Scleroderma, Localized; Scleroderma, Systemic; Tachycardia, Sinus; Young Adult

To investigate the in vivo and in vitro protective effects of pentamethylquercetin (PMQ), a member of polymethoxy flavonoids (PMFs), on cardiac hypertrophy.. An in vivo cardiac hypertrophy model established by abdominal aorta banding technique in rats was treated with PMQ in increasing dosages (2.5, 5, and 10 mg x kg(-1) x d(-1)). An in vitro cardiomyocyte hypertrophy model was induced by treating neonatal cardiomyocytes with endothelin-1 (ET-1, 0.1 μM). An in vitro fibrosis model was developed in cardiac fibroblasts by aldosterone (Ald, 20 nM) and treated with PMQ (0.3, 1, 3 and 10 μM). Hemodynamic, morphological, histological, and biochemical changes were evaluated at corresponding time points.. The abdominal aorta constriction (AAC) rats demonstrated a significantly elevated blood pressure and profound systolic and diastolic cardiac dysfunction. The resultant cardiac hypertrophy and heart failure were characterized by a significant increase in the heart and lung indices (3.51 ± 0.30 vs 2.35 ± 0.24, 5.58 ± 0.85 vs 3.94 ± 0.54; both P < 0.01), cardiomyocyte cross-sectional areas (153 ± 33% vs 100 ± 5%, P < 0.01) and myocardial fibrosis (9.09 ± 1.30% vs 1.49 ± 0.20%, P < 0.01) with concomitant elevation of B-type natriuretic peptide and cardiac collagen mRNA level. Daily oral administration of PMQ (2.5, 5, and 10 mg/kg for 7 weeks) prevented the foregoing histology, gene and protein changes secondary to AAC procedure. In addition, the up-regulated inflammation factors such as TNF-α and IL-6, and the down-regulated PPAR α and PPAR β were normalizd by PMQ treatment.. PMQ has significant protective effects on cardiac hypertrophy through up-regulating the mRNA and protein levels of PPAR α and PPAR β involved in the process of inflammation response and cardiac fibrosis.

Topics: Aldosterone; Animals; Blood Pressure; Cardiomegaly; Cardiotonic Agents; Cells, Cultured; Collagen; Down-Regulation; Endothelin-1; Fibroblasts; Fibrosis; Heart Failure; Hemodynamics; Interleukin-6; Male; Myocytes, Cardiac; Natriuretic Peptide, Brain; PPAR alpha; PPAR-beta; Quercetin; Rats; Rats, Sprague-Dawley; RNA, Messenger; Tumor Necrosis Factor-alpha; Up-Regulation

Peroxisome proliferator-activated receptor alpha (PPARα) has been implicated in the pathogenesis of cardiac hypertrophy, although its mechanism of action remains largely unknown. To determine the effect of PPARα activation on endothelin-1 (ET-1)-induced cardiomyocyte hypertrophy and explore its molecular mechanisms, we evaluated the interaction of PPARα with nuclear factor of activated T-cells c4 (NFATc4) in nuclei of cardiomyocytes from neonatal rats in primary culture. In ET-1-stimulated cardiomyocytes, data from electrophoretic mobility-shift assays (EMSA) and co-immunoprecipitation (co-IP) revealed that fenofibrate (Fen), a PPARα activator, in a concentration-dependent manner, enhanced the association of NFATc4 with PPARα and decreased its interaction with GATA-4, in promoter complexes involved in activation of the rat brain natriuretic peptide (rBNP) gene. Effects of PPARα overexpression were similar to those of its activation by Fen. PPARα depletion by small interfering RNA abolished inhibitory effects of Fen on NFATc4 binding to GATA-4 and the rBNP DNA. Quantitative RT-PCR and confocal microscopy confirmed inhibitory effects of PPARα activation on elevation of rBNP mRNA levels and ET-1-induced cardiomyocyte hypertrophy. Our results suggest that activated PPARα can compete with GATA-4 binding to NFATc4, thereby decreasing transactivation of NFATc4, and interfering with ET-1 induced cardiomyocyte hypertrophy.

Topics: Animals; Cardiomegaly; Cell Nucleus; Dose-Response Relationship, Drug; Endothelin-1; Fenofibrate; GATA4 Transcription Factor; Gene Expression Regulation; Myocytes, Cardiac; Natriuretic Peptide, Brain; NFATC Transcription Factors; PPAR alpha; Promoter Regions, Genetic; Protein Binding; Rats; Rats, Sprague-Dawley; RNA, Messenger

This study sought to examine the potential utility of echocardiography and N-terminal pro-B-type natriuretic peptide (NT-proBNP) for heart failure (HF) risk stratification in concert with a validated clinical HF risk score in older adults.. Without clinical guidance, echocardiography and natriuretic peptides have suboptimal test characteristics for population-wide HF risk stratification. However, the value of these tests has not been examined in concert with a clinical HF risk score.. We evaluated the improvement in 5-year HF risk prediction offered by adding an echocardiographic score and/or NT-proBNP levels to the clinical Health Aging and Body Composition (ABC) HF risk score (base model) in 3,752 participants of the CHS (Cardiovascular Health Study) (age 72.6 ± 5.4 years; 40.8% men; 86.5% white). The echocardiographic score was derived as the weighted sum of independent echocardiographic predictors of HF. We assessed changes in Bayesian information criterion (BIC), C index, integrated discrimination improvement (IDI), and net reclassification improvement (NRI). We examined also the weighted NRI across baseline HF risk categories under multiple scenarios of event versus nonevent weighting.. Reduced left ventricular ejection fraction, abnormal E/A ratio, enlarged left atrium, and increased left ventricular mass were independent echocardiographic predictors of HF. Adding the echocardiographic score and NT-proBNP levels to the clinical model improved BIC (echocardiography: -43, NT-proBNP: -64.1, combined: -68.9; all p < 0.001) and C index (baseline: 0.746; echocardiography: +0.031, NT-proBNP: +0.027, combined: +0.043; all p < 0.01), and yielded robust IDI (echocardiography: 43.3%, NT-proBNP: 42.2%, combined: 61.7%; all p < 0.001), and NRI (based on Health ABC HF risk groups; echocardiography: 11.3%; NT-proBNP: 10.6%, combined: 16.3%; all p < 0.01). Participants at intermediate risk by the clinical model (5% to 20% 5-yr HF risk; 35.7% of the cohort) derived the most reclassification benefit. Echocardiography yielded modest reclassification when used sequentially after NT-proBNP.. In older adults, echocardiography and NT-proBNP offer significant HF risk reclassification over a clinical prediction model, especially for intermediate-risk individuals.

Topics: Aged; Biomarkers; Cardiomegaly; Echocardiography; Female; Heart Failure; Humans; Male; Natriuretic Peptide, Brain; Peptide Fragments; Risk; Risk Assessment; Ventricular Function, Left

Because of the crucial role of the endocrine heart in maintaining homeostasis, considerable effort has been focused on the elucidation of the mechanistic underlying gene expression and secretion of the cardiac hormones atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP). However, much remains to be determined regarding specific molecular events involved in cardiocyte secretory function. In this work, we identified genes involved in the transcriptional response of the endocrine heart to volume overload (VO) and signaling pathways involved in its regulation. To this end, the cardiac atrial and ventricular transcriptomes were analyzed in the heart of rats subjected to experimentally induced aorto-caval shunt VO. Pathway analysis revealed unique gene expression profiles in the VO atria for G-protein signaling, notably a significant downregulation of Ras dexamethasone-induced protein 1 (RASD1). In vitro, knockdown of RASD1 in the atrial-derived HL-1 cells, significantly increased ANF secretion. Concurrent knockdown of RASD1 and its effectors Gα(o1) or Gβ(1)γ(2) abrogated the endocrine response, demonstrating a previously unknown negative modulator role for RASD1. RASD1 thus emerges as a tonic inhibitor of ANF secretion and illustrates for the first time the concept of inhibitory protein regulators of ANF release. The novel molecular function identified herein for RASD1 is of considerable importance given its therapeutic implications for cardiovascular disease.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Cell Line; Cells, Cultured; Gene Expression Profiling; GTP-Binding Proteins; In Vitro Techniques; Male; Models, Animal; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; ras Proteins; Rats; Rats, Sprague-Dawley; RNA Interference; Signal Transduction

Overaggressive fluid resuscitation in elderly patients requiring pancreatectomy can delay recovery and increase morbidity. Despite advancements, no accurate and reproducible methods exist to evaluate effective intravascular volume status in the postoperative setting. We hypothesized that sequential measurement of currently available serum proteins will indicate fluid balance.. Clinicopathologic (n = 44) and echocardiogram (echo) data (n = 18) were collected on patients receiving pancreatectomy or diagnostic laparoscopy (n = 5). Measured fluid balance, serum BUN, creatinine (CR), and brain natriuretic peptide (BNP) levels were recorded on postoperative days (POD) 1 to 7 (only POD1 for diagnostic laparoscopy). ANOVA and bivariate random effect models examined the correlation between BNP and BUN/CR and fluid balance. Linear mixed-effect models examined the correlation between factors associated with vascular stiffness and BNP, BUN/CR, and fluid balance.. On POD1 after diagnostic laparoscopy, the fluid balance was positive by 3,265 mL and was accompanied by a >300-point increase in BNP (p = 0.0083). After pancreatectomy, a similar increase in BNP (250 pg/mL) and fluid balance (4,492 mL) on POD1 was observed. During the return to euvolemia, the change in serum BNP levels correlated with fluid balance changes during POD 1 to 3 (p = 0.039), and BUN/CR levels correlated with fluid balance during POD 4 to 7. Patients with risk factors associated with cardiovascular stiffness or echo evidence of poor compliance experienced higher BNP during the postoperative period.. Fluid loading at surgery is accompanied by an increase in serum BNP, and return to a balanced fluid state after pancreatectomy is paralleled by changes in BNP and BUN/CR levels.

Topics: Aged; Analysis of Variance; Cardiomegaly; Elasticity; Environmental Monitoring; Female; Heart Atria; Humans; Hypertension; Laparoscopy; Length of Stay; Male; Middle Aged; Models, Biological; Natriuretic Peptide, Brain; Pancreatectomy; Postoperative Care; Postoperative Complications; Retrospective Studies; Ultrasonography; Water-Electrolyte Balance

New therapeutic targets for cardiac hypertrophy, an independent risk factor for heart failure and death, are essential. HNO is a novel redox sibling of NO• attracting considerable attention for the treatment of cardiovascular disorders, eliciting cGMP-dependent vasodilatation yet cGMP-independent positive inotropy. The impact of HNO on cardiac hypertrophy (which is negatively regulated by cGMP) however has not been investigated.. Neonatal rat cardiomyocytes were incubated with angiotensin II (Ang II) in the presence and absence of the HNO donor Angeli's salt (sodium trioxodinitrate) or B-type natriuretic peptide, BNP (all 1 µmol/L). Hypertrophic responses and its triggers, as well as cGMP signaling, were determined.. We now demonstrate that Angeli's salt inhibits Ang II-induced hypertrophic responses in cardiomyocytes, including increases in cardiomyocyte size, de novo protein synthesis and β-myosin heavy chain expression. Angeli's salt also suppresses Ang II induction of key triggers of the cardiomyocyte hypertrophic response, including NADPH oxidase (on both Nox2 expression and superoxide generation), as well as p38 mitogen-activated protein kinase (p38MAPK). The antihypertrophic, superoxide-suppressing and cGMP-elevating effects of Angeli's salt were mimicked by BNP. We also demonstrate that the effects of Angeli's salt are specifically mediated by HNO (with no role for NO• or nitrite), with subsequent activation of cardiomyocyte soluble guanylyl cyclase (sGC) and cGMP signaling (on both cGMP-dependent protein kinase, cGK-I and phosphorylation of vasodilator-stimulated phosphoprotein, VASP).. Our results demonstrate that HNO prevents cardiomyocyte hypertrophy, and that cGMP-dependent NADPH oxidase suppression contributes to these antihypertrophic actions. HNO donors may thus represent innovative pharmacotherapy for cardiac hypertrophy.

Topics: Angiotensin II; Animals; Cardiomegaly; Cell Adhesion Molecules; Cyclic GMP; Endothelin-1; Guanylate Cyclase; Microfilament Proteins; Myocytes, Cardiac; NADPH Oxidases; Natriuretic Peptide, Brain; Nitrites; Nitrogen Oxides; p38 Mitogen-Activated Protein Kinases; Phosphoproteins; Phosphorylation; Rats; Reactive Oxygen Species; Receptors, Cytoplasmic and Nuclear; Signal Transduction; Soluble Guanylyl Cyclase; Superoxides

Evidence has shown that endoplasmic reticulum stress (ERS) is associated with the pathogenesis of cardiac hypertrophy. The aim of this study was to investigate whether direct alleviation of ER stress by 4-phenylbutyric acid (PBA), a known chemical chaperone drug, could attenuate pressure-overload cardiac hypertrophy in mice. The effects of orally administered PBA (100mg/kg body weight daily for a week) were examined using mice undergoing transverse aortic constriction (TAC-mice), an animal model to produce pressure overload. TAC application for 1 week led to a 1.8-fold increase in the ratio of the heart weight over body weight (HW/BW) and up-regulation of the hypertrophy markers ANF and BNF accompanied by up-regulation of ERS markers (GRP78, p-PERK, and p-elF2α). The oral administration of PBA to the TAC-mice reduced hypertrophy (19%) and severely downregulated the fibrosis-related genes (transforming growth factor-β1, phospho-smad2, and pro-collagen isoforms). We conclude that ERS is induced as a consequence of remodeling during pathological hypertrophy and that PBA may help to relieve ERS and play a protective role against cardiac hypertrophy and possibly heart failure. We suggest PBA as a novel therapeutic agent for cardiac hypertrophy and fibrosis.

Topics: Administration, Oral; Animals; Aorta; Apoptosis; Atrial Natriuretic Factor; Biomarkers; Cardiomegaly; Disease Models, Animal; DNA-Binding Proteins; eIF-2 Kinase; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Heat-Shock Proteins; Hypertension; Mice; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phenylbutyrates; Pressure; Transcription Factors; Unfolded Protein Response

Acute arsenic (As(III)) exposure has been reported to cause cardiac toxicity, however this toxicity was never linked to the disturbance in cytochrome P450 (P450)-mediated arachidonic acid metabolism. Therefore, we investigated the effect of acute As(III) toxicity on the expression of P450 and soluble epoxide hydrolase (sEH) and their associated arachidonic acid metabolism in mice hearts. As(III) toxicity was induced by a single intraperitoneal injection of 12.5 mg/kg of As(III). Our results showed that As(III) treatment caused a significant induction of the cardiac hypertrophic markers in addition to Cyp1b1, Cyp2b, Cyp2c, Cyp4f, and sEH gene expression in mice hearts. Furthermore, As(III) increased sEH protein expression and activity in hearts with a consequent decrease in 11,12-, and 14,15-epoxyeicosatrienoic acids (EETs) formation. Whereas the formation of 8,9-, 11,12-, 14,15-dihydroxyeicosatrienoic acids (DHETs) was significantly increased. As(III) also increased sEH mRNA and protein expression levels in addition to the hypertrophic markers which was reversed by knockdown of sEH in H9c2 cells. In conclusion, acute As(III) toxicity alters the expression of several P450s and sEH enzymes with a consequent decrease in the cardioprotective EETs which may represent a novel mechanism by which As(III) causes progressive cardiotoxicity. Furthermore, inhibiting sEH might represent a novel therapeutic approach to prevent As(III)-induced hypertrophy.

Topics: Animals; Arachidonic Acid; Arsenic; Atrial Natriuretic Factor; Biomarkers; Cardiomegaly; Cyclooxygenase 2; Cytochrome P-450 Enzyme System; Cytokines; Epoxide Hydrolases; Gene Expression Regulation; Gene Knockdown Techniques; Male; Mice; Mice, Inbred C57BL; Myocardium; Natriuretic Peptide, Brain; Rats; RNA, Messenger; RNA, Small Interfering; Solubility; Toxicity Tests, Acute

Cardiac remodeling is a deleterious consequence of arterial hypertension. This remodeling results in cardiac transcriptomic changes induced by mechanical and hormonal factors (angiotensin II and aldosterone are the most important). The major features of cardiac remodeling are the hypertrophy of cardiomyocytes, interstitial and perivascular fibrosis, and microvascular rarefaction. Inappropriate stimulation of the renin-angiotensin-aldosterone system (RAAS) participates to the development of heart failure. The respective roles of angiotensin II and aldosterone in cardiac remodeling are poorly understood. The development of fibrosis in the heart depends of a balance between profibrotic (TGFβ, CTGF, inflammation) and antifibrotic (BNP, ANP, BMP4 and BMP7) factors. The profibrotic and proinflammatory effects of angiotensin II and aldosterone are very well demonstrated; however, their actions on antifibrotic factors expression are unknown. In order to explore this, we used RenTgKC mice overexpressing renin into the liver, leading to an increased plasma angiotensin II and thus induction of severe hypertension, and AS mice overexpressing aldosterone synthase (AS) in cardiomyocytes which have a doubled intracardiac aldosterone concentration. Male AS mice have a dysfunction of the coronary arteries relaxation without structural and functional changes of the myocardium. Mice derived from a crossing between the RenTgKC and AS strains were used in this work. It is shown that angiotensin II induces the expression of BNP and BMPs which ultimately slows the progression of myocardial fibrosis, and that aldosterone inhibits the expression of these factors and thus worsens the fibrosis.

Topics: Aldosterone; Angiotensin II; Animals; Bone Morphogenetic Proteins; Cardiomegaly; Disease Models, Animal; Fibrosis; Gene Expression Regulation; Heart Failure; Hypertension; Male; Mice; Mice, Transgenic; Myocytes, Cardiac; Natriuretic Peptide, Brain; Renin; Renin-Angiotensin System

Vasopeptidase inhibition (VPI), a therapeutic strategy by dual inhibition of both ACE and neutral endopeptidase 24.11, has not shown a prognostic benefit over ACE inhibition in chronic severe heart failure (CHF). Nevertheless, the effects of early treatment by VPI on cardiac remodelling have not been well assessed. We analysed the effects of early chronic VPI (50 mg/kg/day Omapatrilat) on cardiac remodelling and neurohumoral function during the progression of rapid ventricular pacing-induced heart failure in rabbits (early left ventricular dysfunction [ELVD]: 10 days at 330 bpm, CHF: further 10 days at 360 bpm). VPI-treated animals (ELVD-VPI n = 6; CHF-VPI n = 8) and placebo treated animals (ELVD n = 6; CHF n = 7) were compared with control rabbits (CTRL n = 5). LV fractional shortening (FS) and enddiastolic diameter (LVEDD) were assessed by echocardiography (12 MHz probe). LV BNP- and LV IL-6 gene expression was analysed quantitatively by real time PCR. Neurohumoral function was assessed by ANP, cGMP, plasma renin activity (PRA) and Aldosterone. In ELVD, LVEDD and atrial mass were significantly increased (both p < 0.05). This increase was markedly attenuated by VPI (both p < 0.05 vs. placebo). CHF was associated with a further increase in atrial mass and an increase in LV mass (both p < 0.05), which was again attenuated by VPI (atrial mass, p < 0.05 vs. untreated). LV BNP mRNA was significantly increased in CHF (p < 0.05 vs. control), and chronic VPI completely abolished this increase in ELVD and significantly attenuated it in CHF (p < 0.05 vs. CHF-placebo). Beyond that, the increase of cGMP was augmented by chronic VPI (p < 0.05 vs. placebo in CHF) in heart failure and that of Aldosterone was attenuated (p < 0.05 vs. placebo in ELVD), whereas PRA was temporarily increased (p < 0.05 vs. placebo in ELVD). Combined inhibition of ACE and NEP by VPI significantly inhibits early cardiac remodelling and LV BNP gene expression. If initiated early enough, it may slow down cardiac remodelling and represents a promising therapeutic strategy in progressive heart failure.

Topics: Aldosterone; Angiotensin-Converting Enzyme Inhibitors; Animals; Cardiomegaly; Cardiovascular Agents; Disease Models, Animal; Gene Expression Regulation; Heart Failure; Male; Natriuretic Peptide, Brain; Neprilysin; Pyridines; Rabbits; Renin; Renin-Angiotensin System; RNA, Messenger; Tachycardia; Thiazepines; Ventricular Dysfunction, Left; Ventricular Remodeling

Various experimental and clinical studies strongly support a cigarette smoke-heart disease association and suggest possible mechanisms, unfortunately, the involvement of genetic modulations remain unexplored. Thus, the main aim of the current study was to evaluate the effects of sub-chronic cigarette smoke exposure on the mRNA expression of cardiac hypertrophy genes, cytochrome P450 (CYP) enzymes, and the oxidative stress markers in heart rats. For this purpose, Wistar albino rats were exposed to increasing doses of passive cigarette smoke 2, 4, 8, and 24 cigarettes per day for 7 consecutive days. The mRNA expression of fifteen cardiac genes was determined using real-time polymerase chain reaction. Our results showed that the levels of hypertrophic genes; atrial natriuretic peptide, brain natriuretic peptide, and β-myosin heavy chain were significantly induced, whereas the anti-hypertrophic gene α-myosin heavy chain was dramatically inhibited, in heart tissues of passive-smoke-exposed groups compared with normal-control groups. This was accompanied with a significant induction of CYP enzymes; CYP1A1, CYP2C11, CYP2E1, and CYP3A2, and the expression of oxidative stress genes, heme oxygenase 1, catalase, cyclooxygenase, and glutathione S-Transferase. The ability of cigarette smoke to induce cardiac hypertrophic genes, CYPs enzymes, and oxidative stress, collectively explore the molecular mechanism of cigarette smoke-induced cardiac diseases and brings further investigative attention to the public health issue of the injurious effects of chronic passive smoke exposure. In conclusion, sub-chronic environmental tobacco smoke exposure increases the incidence of cardiovascular diseases through modulation of cardiac genes.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Catalase; Cyclooxygenase 2; Cytochrome P-450 Enzyme System; Gene Expression Regulation; Glutathione Transferase; Heme Oxygenase (Decyclizing); Isoenzymes; Male; Natriuretic Peptide, Brain; Oxidative Stress; Rats; Rats, Wistar; Tobacco Smoke Pollution; Ventricular Myosins

In vitro models of cardiac hypertrophy focus exclusively on applying "external" dynamic signals (electrical, mechanical, and chemical) to achieve a hypertrophic state. In contrast, here we set out to demonstrate the role of "self-organized" cellular architecture and activity in reprogramming cardiac cell/tissue function toward a hypertrophic phenotype. We report that in neonatal rat cardiomyocyte culture, subtle out-of-plane microtopographic cues alter cell attachment, increase biomechanical stresses, and induce not only structural remodeling, but also yield essential molecular and electrophysiological signatures of hypertrophy. Increased cell size and cell binucleation, molecular up-regulation of released atrial natriuretic peptide, altered expression of classic hypertrophy markers, ion channel remodeling, and corresponding changes in electrophysiological function indicate a state of hypertrophy on par with other in vitro and in vivo models. Clinically used antihypertrophic pharmacological treatments partially reversed hypertrophic behavior in this in vitro model. Partial least-squares regression analysis, combining gene expression and functional data, yielded clear separation of phenotypes (control: cells grown on flat surfaces; hypertrophic: cells grown on quasi-3-dimensional surfaces and treated). In summary, structural surface features can guide cardiac cell attachment, and the subsequent syncytial behavior can facilitate trophic signals, unexpectedly on par with externally applied mechanical, electrical, and chemical stimulation.

Topics: Animals; Animals, Newborn; Atrial Natriuretic Factor; Cardiomegaly; Cell Adhesion; Cell Shape; Cells, Cultured; Electric Stimulation; Genetic Markers; Mechanotransduction, Cellular; Myocardial Contraction; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phenotype; Physical Stimulation; Rats; Signal Transduction; Stimulation, Chemical; Tissue Scaffolds

Cardiac hypertrophy involves growth responses to a variety of stimuli triggered by increased workload. It is an independent risk factor for heart failure and sudden death. Mammalian target of rapamycin (mTOR) plays a key role in cellular growth responses by integrating growth factor and energy status signals. It is found in 2 structurally and functionally distinct multiprotein complexes called mTOR complex (mTORC) 1 and mTORC2. The role of each of these branches of mTOR signaling in the adult heart is currently unknown.. We generated mice with deficient myocardial mTORC1 activity by targeted ablation of raptor, which encodes an essential component of mTORC1, during adulthood. At 3 weeks after the deletion, atrial and brain natriuretic peptides and β-myosin heavy chain were strongly induced, multiple genes involved in the regulation of energy metabolism were altered, but cardiac function was normal. Function deteriorated rapidly afterward, resulting in dilated cardiomyopathy and high mortality within 6 weeks. Aortic banding-induced pathological overload resulted in severe dilated cardiomyopathy already at 1 week without a prior phase of adaptive hypertrophy. The mechanism involved a lack of adaptive cardiomyocyte growth via blunted protein synthesis capacity, as supported by reduced phosphorylation of ribosomal S6 kinase 1 and 4E-binding protein 1. In addition, reduced mitochondrial content, a shift in metabolic substrate use, and increased apoptosis and autophagy were observed.. Our results demonstrate an essential function for mTORC1 in the heart under physiological and pathological conditions and are relevant for the understanding of disease states in which the insulin/insulin-like growth factor signaling axis is affected such as diabetes mellitus and heart failure or after cancer therapy.

Topics: Adaptor Proteins, Signal Transducing; Animals; Apoptosis; Atrial Natriuretic Factor; Autophagy; Cardiomegaly; Carrier Proteins; Cell Cycle Proteins; Energy Metabolism; Eukaryotic Initiation Factors; Gene Expression; Heart Failure; Heart Rate; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitochondria, Heart; Myosin Heavy Chains; Natriuretic Peptide, Brain; Nonmuscle Myosin Type IIB; Phosphoproteins; Phosphorylation; Regulatory-Associated Protein of mTOR; Ribosomal Protein S6 Kinases, 90-kDa

Resistin has been suggested to be involved in the development of diabetes and insulin resistance. We recently reported that resistin is expressed in diabetic hearts and promotes cardiac hypertrophy; however, the mechanisms underlying this process are currently unknown. Therefore, we wanted to elucidate the mechanisms associated with resistin-induced cardiac hypertrophy and myocardial insulin resistance. Overexpression of resistin using adenoviral vector in neonatal rat ventricular myocytes was associated with inhibition of AMP-activated protein kinase (AMPK) activity, activation of tuberous sclerosis complex 2/mammalian target of rapamycin (mTOR) pathway, and increased cell size, [(3)H]leucine incorporation (i.e. protein synthesis) and mRNA expression of the hypertrophic marker genes, atrial natriuretic factor, brain natriuretic peptide, and β-myosin heavy chain. Activation of AMPK with 5-aminoimidazole-4-carbozamide-1-β-D-ribifuranoside or inhibition of mTOR with rapamycin or mTOR siRNA attenuated these resistin-induced changes. Furthermore, resistin increased serine phosphorylation of insulin receptor substrate (IRS1) through the activation of the apoptosis signal-regulating kinase 1/c-Jun N-terminal Kinase (JNK) pathway, a module known to stimulate insulin resistance. Inhibition of JNK (with JNK inhibitor SP600125 or using dominant-negative JNK) reduced serine 307 phosphorylation of IRS1. Resistin also stimulated the activation of p70(S6K), a downstream kinase target of mTOR, and increased phosphorylation of the IRS1 serine 636/639 residues, whereas treatment with rapamycin reduced the phosphorylation of these residues. Interestingly, these in vitro signaling pathways were also operative in vivo in ventricular tissues from adult rat hearts overexpressing resistin. These data demonstrate that resistin induces cardiac hypertrophy and myocardial insulin resistance, possibly via the AMPK/mTOR/p70(S6K) and apoptosis signal-regulating kinase 1/JNK/IRS1 pathways.

Topics: AMP-Activated Protein Kinases; Animals; Apoptosis; Biomarkers; Cardiomegaly; Cells, Cultured; Enzyme Inhibitors; Gene Expression Regulation; Insulin Receptor Substrate Proteins; Insulin Resistance; JNK Mitogen-Activated Protein Kinases; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phosphorylation; Rats; Rats, Sprague-Dawley; Resistin; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; TOR Serine-Threonine Kinases; Ventricular Myosins

Pathological cardiac hypertrophy induced by adrenergic overactivation can subsequently develop to heart failure which remains as a leading cause of mortality worldwide. Tanshinone IIA is a lipid-soluble pharmacologically active compound extracted from the rhizome of the Chinese herb Salvia miltiorrhiza, a well-known traditional Chinese medicine used for the treatment of cardiovascular disorders. However, little is know about the effect of Tanshinone IIA on cardiac hypertrophy. The present study was aimed to investigate whether Tanshinone IIA prevents cardiac hypertrophy induced by isoproterenol (ISO) and to clarify its possible mechanisms. Cardiomyocytes hypertrophy was induced by ISO 10 μM for 48 h with or without Tanshinone IIA 10, 30, 100 μM pretreatment, and evaluated by determining the cell size and the expression of ANP, BNP, β-MHC, Calcineurin, and NFATc3 by real-time PCR and western blot. We found that Tanshinone IIA pretreatment attenuated the enlargement of cell surface area induced by ISO in cultured cardiomyocytes. The mRNA level of ANP, BNP and β-MHC was obviously elevated in ISO-treated cardiac cells, which was effectively inhibited by Tanshinone IIA. Moreover, we found that Tanshinone IIA pretreatment could prevent the augment of intracellular calcium transient in ISO-treated cardiomyocytes. The further study revealed that Calcineurin, NFATc3, ANP, BNP and β-MHC proteins were upregulated by ISO in ventricular myocytes, and Tanshinone IIA pretreatment significantly attenuate the increased expression of Calcineurin, NFATc3, ANP, BNP and β-MHC proteins. In summary, Tanshinone IIA attenuated cardiomyocyte hypertrophy induced by ISO through inhibiting Calcineurin/NFATc3 pathway, which provides new insights into the pharmacological role and therapeutic mechanism of Tanshinone IIA in heart diseases.

Topics: Abietanes; Animals; Atrial Natriuretic Factor; Calcineurin; Calcium Signaling; Cardiomegaly; Drugs, Chinese Herbal; Isoproterenol; Medicine, Chinese Traditional; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; NFATC Transcription Factors; Rats; RNA, Messenger; Up-Regulation

We hypothesized that cardiac myocyte-specific overexpression of caveolin-3 (Cav-3), a muscle-specific caveolin, would alter natriuretic peptide signaling and attenuate cardiac hypertrophy.. Natriuretic peptides modulate cardiac hypertrophy and are potential therapeutic options for patients with heart failure. Caveolae, microdomains in the plasma membrane that contain caveolin proteins and natriuretic peptide receptors, have been implicated in cardiac hypertrophy and natriuretic peptide localization.. We generated transgenic mice with cardiac myocyte-specific overexpression of caveolin-3 (Cav-3 OE) and also used an adenoviral construct to increase Cav-3 in cardiac myocytes.. The Cav-3 OE mice subjected to transverse aortic constriction had increased survival, reduced cardiac hypertrophy, and maintenance of cardiac function compared with control mice. In left ventricle at baseline, messenger ribonucleic acid for atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were increased 7- and 3-fold, respectively, in Cav-3 OE mice compared with control subjects and were accompanied by increased protein expression for ANP and BNP. In addition, ventricles from Cav-3 OE mice had greater cyclic guanosine monophosphate levels, less nuclear factor of activated T-cell nuclear translocation, and more nuclear Akt phosphorylation than ventricles from control subjects. Cardiac myocytes incubated with Cav-3 adenovirus showed increased expression of Cav-3, ANP, and Akt phosphorylation. Incubation with methyl-β-cyclodextrin, which disrupts caveolae, or with wortmannin, a PI3K inhibitor, blocked the increase in ANP expression.. These results imply that cardiac myocyte-specific Cav-3 OE is a novel strategy to enhance natriuretic peptide expression, attenuate hypertrophy, and possibly exploit the therapeutic benefits of natriuretic peptides in cardiac hypertrophy and heart failure.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Caveolae; Caveolin 3; Cyclic GMP; Heart Failure; Immunoenzyme Techniques; In Vitro Techniques; Mice; Mice, Knockout; Mice, Transgenic; Myocytes, Cardiac; Natriuretic Peptide, Brain; NFATC Transcription Factors; RNA, Messenger

This study tested the hypothesis that experimental prediabetes can elicit structural remodelling in the left ventricle (LV). Left ventricles isolated from 8-week-old male Goto-Kakizaki (GK) rats and age-matched male Wistar control rats were used to assess remodelling changes and underlying transforming growth factor β1 (TGFβ1) activity, prohypertrophic Akt-p70S6K1 signalling and gene expression profile of the extracellular matrix (ECM) using histological, immunohistochemical, immunoblotting and quantitative gene expression analyses. Prediabetes in GK rats was confirmed by impaired glucose tolerance and modestly elevated fasting blood glucose. Left ventricle remodelling in the GK rat presented with marked hypertrophy of cardiomyocytes and increased ECM deposition that together translated into increased heart size in the absence of ultrastructural changes or fibre disarray. Molecular derangements underlying this phenotype included recapitulation of the fetal gene phenotype markers B-type natriuretic peptide and α-skeletal muscle actin, activation of the Akt-p70S6K1 pathway and altered gene expression profile of key components (collagen 1α and fibronectin) and modulators of the ECM (matrix metalloproteinases 2 and 9 and connective tissue growth factor). These changes were correlated with parallel findings of increased TGFβ1 transcription and activation in the LV and elevated active TGFβ1 in plasma of GK rats compared with control animals (Student's t test, P < 0.05 versus age-matched Wistar control animals for all parameters). This is the first report to describe LV structural remodelling in experimental prediabetes. The results suggest that ventricular decompensation pathognomonic of advanced diabetic cardiomyopathy may have possible origins in profibrotic and prohypertrophic mechanisms triggered before the onset of type 2 diabetes mellitus.

Topics: Animals; Cardiomegaly; Diabetes Mellitus, Type 2; Extracellular Matrix Proteins; Heart Ventricles; Male; Natriuretic Peptide, Brain; Prediabetic State; Proto-Oncogene Proteins c-akt; Rats; Rats, Inbred Strains; Rats, Wistar; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Transforming Growth Factor beta1; Ventricular Remodeling

Adrenomedullin (ADM) has been recognized as a multipotent multifunctional peptide. To explore the pathophysiological roles of ADM in insulin resistance (IR), we studied the changes in ADM mRNA level in the myocardium and vessels and the effect of ADM supplementation on rats with IR induced by fructose feeding. Rats were fed 4% fructose in drinking water for 8 weeks, and ADM was administered subcutaneously in pure water through an Alzet Mini-osmotic Pump at 300 ng/kg/h for the last 4 weeks. Compared with controls, rats with IR showed increased levels of fasting blood sugar and serum insulin, by 95% and 67%, respectively (all P<0.01), and glycogen synthesis and glucose transport activity of the soleus decreased by 54% and 55% (all P<0.01). mRNA level and content of brain natriuretic peptide (BNP) in myocardial were all increased significantly. Fructose-fed rats showed increased immunoreactive-ADM content in plasma by 110% and in myocardia by 55% and increased mRNA level in myocardia and vessels (all P<0.01). ADM administration ameliorated the induced IR and myocardial hypertrophy. The glycogen synthesis and glucose transport activity of the soleus muscle increased by 41% (P<0.01) and 32% (P<0.05). ADM therapy attenuated myocardial and soleus lipid peroxidation injury and enhanced the antioxidant ability. Our results showed upregulation of endogenous ADM during fructose-induced IR and the protective effect of ADM on fructose-induced IR and concomitant cardiovascular hypertrophy probably by its antioxidant effect, which suggests that ADM could be an endogenous protective factor in IR.

Topics: Adrenomedullin; Animals; Blood Glucose; Cardiomegaly; Cardiotonic Agents; Fructose; Glycogen; Infusion Pumps; Infusions, Subcutaneous; Insulin; Insulin Resistance; Lipid Peroxidation; Male; Malondialdehyde; Muscle, Skeletal; Myocardium; Natriuretic Peptide, Brain; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

Reactive oxygen species (ROS) induce matrix metalloproteinase (MMP) activity that mediates hypertrophy and cardiac remodeling. Adiponectin (APN), an adipokine, modulates cardiac hypertrophy, but it is unknown if APN inhibits ROS-induced cardiomyocyte remodeling. We tested the hypothesis that APN ameliorates ROS-induced cardiomyocyte remodeling and investigated the mechanisms involved. Cultured adult rat ventricular myocytes (ARVM) were pretreated with recombinant APN (30 μg/ml, 18 h) followed by exposure to physiologic concentrations of H(2)O(2) (1-200 μM). ARVM hypertrophy was measured by [(3)H]leucine incorporation and atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP) gene expression by RT-PCR. MMP activity was assessed by in-gel zymography. ROS was induced with angiotensin (ANG)-II (3.2 mg·kg(-1)·day(-1) for 14 days) in wild-type (WT) and APN-deficient (APN-KO) mice. Myocardial MMPs, tissue inhibitors of MMPs (TIMPs), p-AMPK, and p-ERK protein expression were determined. APN significantly decreased H(2)O(2)-induced cardiomyocyte hypertrophy by decreasing total protein, protein synthesis, ANF, and BNP expression. H(2)O(2)-induced MMP-9 and MMP-2 activities were also significantly diminished by APN. APN significantly increased p-AMPK in both nonstimulated and H(2)O(2)-treated ARVM. H(2)O(2)-induced p-ERK activity and NF-κB activity were both abrogated by APN pretreatment. ANG II significantly decreased myocardial p-AMPK and increased p-ERK expression in vivo in APN-KO vs. WT mice. ANG II infusion enhanced cardiac fibrosis and MMP-2-to-TIMP-2 and MMP-9-to-TIMP-1 ratios in APN-KO vs. WT mice. Thus APN inhibits ROS-induced cardiomyocyte remodeling by activating AMPK and inhibiting ERK signaling and NF-κB activity. Its effects on ROS and ultimately on MMP expression define the protective role of APN against ROS-induced cardiac remodeling.

Topics: Adiponectin; AMP-Activated Protein Kinases; Analysis of Variance; Angiotensin II; Animals; Atrial Natriuretic Factor; Cardiomegaly; Cells, Cultured; Disease Models, Animal; Extracellular Signal-Regulated MAP Kinases; Fibrosis; Genes, Reporter; Hydrogen Peroxide; Hypertrophy, Left Ventricular; Male; Matrix Metalloproteinases; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocytes, Cardiac; NADPH Oxidases; Natriuretic Peptide, Brain; NF-kappa B; Oxidants; Oxidative Stress; Phosphorylation; Rats; Reactive Oxygen Species; Recombinant Proteins; RNA, Messenger; Signal Transduction; Time Factors; Transfection; Ventricular Remodeling

Endothelin-1 (ET-1) induces cardiac hypertrophy, whereas adiponectin may elicit protective effects in the vasculature and myocardium. We therefore evaluated the relationship between plasma ET-1 and adiponectin levels in heart failure (HF) patients, and the association between adiponectin expression and ET-1-induced hypertrophy of human cardiomyocytes (HCM) in vitro.. One hundred seventeen patients with chronic HF were enrolled into this study. A group of 7 patients with end-stage HF undergoing heart transplantation was included in the histopathological study. Baseline clinical evaluations and laboratory measurements were performed. HCM cultures were studied to investigate the effect of ET-1 on cell size and adiponectin expression.. Plasma ET-1, adiponectin, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) increased with the severity of HF. Higher New York Heart Association functional class, plasma ET-1, adiponectin, and NT-proBNP levels were significant predictors of adverse outcomes in these patients. The myocardial expression of adiponectin was significantly higher in the recipient hearts of patients undergoing emergency or urgent heart transplantation. In cell culture, ET-1 significantly increased cell size and adiponectin expression in HCM.. Adiponectin was significantly elevated in HF and was significantly associated with ET-1. The study provides a basis for further investigation of ET-1 and adiponectin modulation as a therapeutic strategy for ventricular remodeling in HF.

Topics: Adiponectin; Body Mass Index; Cardiomegaly; Cell Size; Cells, Cultured; Endothelin-1; Female; Heart Failure; Hospitalization; Humans; Male; Middle Aged; Myocardium; Natriuretic Peptide, Brain; Peptide Fragments; Prognosis

Hydrogen sulphide (H(2)S) has been shown to play a crucial role in cardiovascular physiology and disease. However, there is no information about the possible role of H(2)S in cardiomyocyte hypertrophy (CH). Our results showed that pretreatment with NaHS, an H(2)S donor, significantly reduced [(3)H]-leucine incorporation, cell surface area, mRNA expression of brain natriuretic peptide (BNP), intracellular reactive oxygen species (ROS), miR-21 and increased atrial natriuretic peptide (ANP) and miR-133a expression in hypertrophic cardiomyocytes. Anti-miR133a inhibitor transfection partly reduced the anti-hypertrophic effect of NaHS. In conclusion, H(2)S is a direct inhibitor of CH; it acts by increasing miR-133a and inhibiting the increase in intracellular ROS.

Topics: Animals; Cardiomegaly; Cell Line; Hydrogen Sulfide; Hypertrophy; MicroRNAs; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats; Reactive Oxygen Species; RNA, Messenger; Sulfides; Up-Regulation

1. Previously, we showed that long-term treatment of rats after myocardial infarction (MI) with B-type natriuretic peptide (BNP) prevented ventricular remodelling. However, it is unclear whether long-term BNP treatment affects cardiac hypertrophy and, if so, its mechanism of action. In the present study, we investigated the effects of long-term BNP treatment on cardiac hypertrophy and the molecular mechanisms involved. 2. Cardiac hypertrophy was established in rats by ligation of the left anterior descending coronary artery. After treatment with BNP (5 or 15 microg/kg per day) for 8 weeks, indices of cardiac hypertrophy were determined. In separate in vitro experiments, cardiomyocyte hypertrophy was induced by treatment of cardiomyocytes with 10(-6) mol/L angiotensin (Ang) II for 48 h and cell surface area and [(3)H] incorporation were measured. Transforming growth factor (TGF)-beta1 and smad7 mRNA and protein expression in vivo and in vitro were detected using reverse transcription-polymerase chain reaction and western blotting. 3. Long-term BNP treatment dose-dependently attenuated cardiac hypertrophy and improved cardiac function in rats after MI. Furthermore, BNP attenuated the upregulation of TGF-beta1 and downregulation of smad7 mRNA and protein expression. The in vitro experiments further proved that BNP inhibited cardiac hypertrophy and changes in the TGF-beta1/smad7 pathway, which were completely blocked by the cyclic GMP-dependent protein kinase (PKG) inhibitor, KT5823 (cells were treated with 10(-6) mol/L KT5823 for 48 h). 4. The results of the present study demonstrate that long-term treatment of rats with BNP dose-dependently attenuates cardiac hypertrophy and that this is associated with downregulation of TGF-beta1 and upregulation of smad7 via PKG signalling. Long-term BNP treatment may be a new therapeutic strategy to prevent cardiac hypertrophy and progression to heart failure.

Topics: Animals; Cardiomegaly; Cells, Cultured; Dose-Response Relationship, Drug; Male; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley; Signal Transduction; Smad7 Protein; Transforming Growth Factor beta1

The mixed-lineage kinases (MLKs) act upstream of mitogen-activated protein kinases, but their role in cardiac biology and pathology is largely unknown.. We investigated the effect of a MLK1-3 inhibitor CEP-11004 on G protein-coupled receptor agonist-induced stress response in neonatal rat cardiac myocytes in culture.. CEP-11004 administration dose-dependently attenuated phenylephrine and endothelin-1 (ET-1)-induced c-Jun N-terminal kinase activation. MLK inhibition also reduced ET-1- and phenylephrine-induced phosphorylation of p38 mitogen-activated protein kinase. In contrast, phenylephrine-induced extracellular signal-regulated kinase phosphorylation was further up-regulated by CEP-11004. ET-1 increased activator protein-1 binding activity 3.5-fold and GATA-binding protein 4 (GATA-4) binding activity 1.8-fold, both of which were attenuated with CEP-11004 administration by 59% and 63% respectively. Phenylephrine induced activator protein-1 binding activity by 2.6-fold, which was decreased by 81% with CEP-11004 administration. Phenylephrine also induced a 3.7-fold increase in the transcriptional activity of B-type natriuretic peptide (BNP), which was attenuated by 41% with CEP-11004 administration. In agreement, MLK inhibition also reduced hypertrophic agonist-induced secretion of immunoreactive atrial natriuretic peptide and BNP.. These results showed that inhibition of the MLK1-3 signalling pathway was sufficient for suppressing the activity of key nuclear effectors (GATA-4 and activator protein-1 transcription factors) in cardiac hypertrophy, and attenuated the agonist-induced atrial natriuretic peptide secretion and activation of BNP gene transcription.

Topics: Animals; Animals, Newborn; Atrial Natriuretic Factor; Carbazoles; Cardiomegaly; Cell Nucleus; Endothelin-1; Genes, jun; Heart; Hypertrophy; JNK Mitogen-Activated Protein Kinases; MAP Kinase Kinase Kinases; Mitogen-Activated Protein Kinase Kinase Kinase 11; Mitogen-Activated Protein Kinases; Myocytes, Cardiac; Natriuretic Peptide, Brain; p38 Mitogen-Activated Protein Kinases; Phenylephrine; Phosphorylation; Rats; Rats, Sprague-Dawley; Signal Transduction; Transcription Factor AP-1; Transcription Factors

This study was aimed to investigate whether the antihypertrophic effects of adiponectin in murine hearts are associated with the modulation of HB-EGF signaling. We determined the myocardial expressions of adiponectin and adiponectin receptors, brain natriuretic peptide (BNP), and HB-EGF in normal and hypertrophied hearts of adiponectin knockout mice or wild-type mice with transverse aortic constriction (TAC). Then, we observed the effects of adiponectin on cardiac hypertrophy and HB-EGF signaling in cultured neonatal rat cardiomyocytes and whole hearts of adiponectin-null mice. The myocardial mRNA and protein expressions of adiponectin in the hypertrophied hearts were significantly downregulated, and the mRNA expression of adiponectin was inversely correlated with the heart-to-body weight ratio, BNP, and HB-EGF. The TAC-induced cardiac hypertrophy and EGF receptor (EGFR) activation in the adiponectin knockout mice were significantly greater than those in the wild-type mice. Furthermore, in vitro experiments revealed that adiponectin inhibited HB-EGF-stimulated protein synthesis, HB-EGF shedding, and EGFR phosphorylation. We conclude that the inhibition of HB-EGF mediated EGFR activation is one of the alternative mechanisms for the antihypertrophic action of adiponectin.

Topics: Adiponectin; Animals; Cardiomegaly; Cell Line; Heart Ventricles; Heparin-binding EGF-like Growth Factor; Intercellular Signaling Peptides and Proteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Organ Size; Rats; Signal Transduction

Heart hypertrophy is a common cardiac complication of sustained arterial hypertension and is accompanied by an increased incidence of supraventricular tachyarrhythmia, such as atrial fibrillation and atrial flutter. Verapamil, a phenyalkylamine, belongs to the group of calcium channel antagonists (class IV antiarrhythmic drugs) and is frequently used for the management of supraventricular tachycardia and for ventricular rate control in atrial fibrillation and atrial flutter. Verapamil heart tissue and plasma levels after intraperitoneal dosing of spontaneously hypertensive and normotensive rats were investigated. Transcript expression of various ion channels, ion transporters, calcium handling, and cytoskeletal proteins by reverse transcriptase-polymerase chain reaction (RT-PCR) were further investigated. There was no difference in plasma pharmacokinetics when hypertensive and normotensive animals were compared. Strikingly, the tissue clearance of verapamil was highly significantly impaired in heart tissue of hypertensive animals. Gene expression analysis showed the repression of many cardiac-specific genes in spontaneously hypertensive but not in normotensive rats, therefore providing evidence for different modes of action in healthy and hypertrophic hearts. Verapamil heart tissue levels differed dramatically between normotensive and hypertensive rats and resulted in repression of many cardiac ion channels, ion transporters, and calcium handling proteins. A disturbed ion homeostasis induced by critical tissue levels of verapamil is therefore proposed as a molecular rational for its pro-arrhythmogenic activity. The observed changes can be a significant determinant of spatial electrophysiological heterogeneity, thereby contributing to increased conductance disturbance as observed with some patients.

Topics: Animals; Calcium Channel Blockers; Calcium Channels; Calmodulin; Calsequestrin; Cardiomegaly; Cytoskeletal Proteins; Down-Regulation; Gene Expression; Hypertension; Ion Channels; Male; Myocardium; Natriuretic Peptide, Brain; Rats; Rats, Inbred SHR; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transcription Factors; Verapamil

It was to establish whether brain natriuretic peptide (BNP) might predict cardiac dysfunction in children with chronic kidney disease (CKD).. The relation between BNP, echocardiography and risk factors (hypertension, anemia, lipids, CRP, hyperparathyroidism) was investigated in 46 children (10 pre-dialysis patients, 14 on dialysis, 11 children with kidney transplants, and 11 healthy controls). Data on BNP were transformed into common logarithms (log(10) BNP, log BNP).. log BNP was significantly higher in dialysis patients when compared to controls (2.09 +/- 0.78 vs. 1.43 +/- 0.34 pg/ml, p = 0.012) and patients in the pre-dialysis stage (2.09 +/- 0.78 vs. 1.52 +/- 0.42 pg/ml, p = 0.039). log BNP in transplanted children was not significantly different from healthy children (2.09 +/- 0.78 vs. 1.71 +/- 0.46 pg/ml, p = 0.19). Abnormal heart geometry (concentric and eccentric hypertrophy, concentric remodeling) was found in 19 patients (54.28%). A significant correlation was observed between log BNP and ventricular hypertrophy (r = 0.515, p = 0.001). Compared to controls higher log BNP was seen in children with eccentric hypertrophy than in children with concentric hypertrophy (2.178 +/- 0.956 vs. 1.496 +/- 0.395 pg/ml, p = 0.05, or 1.982 +/- 0.618 vs. 1.496 +/- 0.395, p = 0.04).. BNP might predict an abnormal geometry in children with CKD.

Topics: Adolescent; Biomarkers; Cardiomegaly; Cardiovascular Diseases; Case-Control Studies; Child; Chronic Disease; Echocardiography; Female; Humans; Hypertrophy, Left Ventricular; Kidney Diseases; Male; Natriuretic Peptide, Brain; Predictive Value of Tests; Risk Factors; Young Adult

Mutation of the mitochondrial protein tafazzin causes dilated cardiomyopathy in Barth syndrome. We employed an adenovirus as a vector to transfer tafazzin small hairpin RNA (shRNA) into neonatal ventricular myocytes (NVMs) to investigate the effects of tafazzin knockdown. The tafazzin shRNA adenovirus consistently knocked down tafazzin mRNA and lowered cardiolipin while significantly decreasing the production of ATP by the mitochondria. The phosphorylation of AMP-activated protein kinase and mitochondrial density were both increased in tafazzin knockdown NVMs compared with scrambled shRNA controls. When we tested whether tafazzin knockdown causes hypertrophy in vitro, we found that the surface area of NVMs infected with tafazzin shRNA adenovirus was significantly increased, as were the protein synthesis and expression of the hypertrophic marker gene, brain natriuretic peptide. Taken together, our data support the concept that a decreased tafazzin expression causes cardiomyocyte hypertrophy in vitro.

Topics: Acyltransferases; Adenosine Triphosphate; Adenoviridae; AMP-Activated Protein Kinases; Animals; Animals, Newborn; Cardiolipins; Cardiomegaly; Cells, Cultured; Energy Metabolism; Gene Knockdown Techniques; Genetic Vectors; Heart Ventricles; Mitochondria, Heart; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phosphorylation; Rats; Rats, Sprague-Dawley; RNA Interference; RNA, Messenger; Transcription Factors; Transfection

Intermedin (IMD) is coexpressed in the heart with its receptor, which suggests that it may have localized actions as a modulator of cardiac function. The present study was designed to observe the interaction between IMD and cardiac hypertrophy and the possible mechanism involved in the antihypertrophic effects of IMD1-53 in cultured neonatal ventricular myocytes.. Myocyte hypertrophy was induced by treating the cells with angiotensin II, and the hypertrophic response was characterized by a significant increase in cell surface area, protein synthesis, and BNP mRNA expression.. Our results showed that angiotensin II led to an obvious decrease in the production, secretion, and mRNA expression of IMD and increase receptor activity modifying proteins 1, 3 mRNA expression. Moreover, IMD1-53 inhibited the angiotensin II-induced hypertrophic response and the effects of IMD1-53 were similar to those of equivalent-dose adrenomedullin and could been blocked by H89. Otherwise, in our study, IMD1-53 resulted in dose-dependent increases of cAMP production in cardiomyocytes.. Thus, IMD and its receptor system are involved in cardiac hypertrophy, and like adrenomedullin, IMD1-53 exerts an antihypertrophic effect on neonatal cardiomyocytes and the effect can be mediated by the cAMP/PKA pathway.

Topics: Adrenomedullin; Angiotensin II; Animals; Animals, Newborn; Cardiomegaly; Cells, Cultured; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Heart Ventricles; Myocytes, Cardiac; Natriuretic Peptide, Brain; Neuropeptides; Rats; Rats, Wistar; RNA, Messenger

Atrial natriuretic peptide (ANP), via its guanylyl cyclase A (GC-A) receptor and intracellular guanosine 3',5'-cyclic monophosphate production, is critically involved in the regulation of blood pressure. In patients with chronic heart failure, the plasma levels of ANP are increased, but the cardiovascular actions are severely blunted, indicating a receptor or postreceptor defect. Studies on metabolically labelled GC-A-overexpressing cells have indicated that GC-A is extensively phosphorylated, and that ANP-induced homologous desensitization of GC-A correlates with receptor dephosphorylation, a mechanism which might contribute to a loss of function in vivo. In this study, tandem MS analysis of the GC-A receptor, expressed in the human embryonic kidney cell line HEK293, revealed unambiguously that the intracellular domain of the receptor is phosphorylated at multiple residues: Ser487, Ser497, Thr500, Ser502, Ser506, Ser510 and Thr513. MS quantification based on multiple reaction monitoring demonstrated that ANP-provoked desensitization was accompanied by a complex pattern of receptor phosphorylation and dephosphorylation. The population of completely phosphorylated GC-A was diminished. However, intriguingly, the phosphorylation of GC-A at Ser487 was selectively enhanced after exposure to ANP. The functional relevance of this observation was analysed by site-directed mutagenesis. The substitution of Ser487 by glutamate (which mimics phosphorylation) blunted the activation of the GC-A receptor by ANP, but prevented further desensitization. Our data corroborate previous studies suggesting that the responsiveness of GC-A to ANP is regulated by phosphorylation. However, in addition to the dephosphorylation of the previously postulated sites (Ser497, Thr500, Ser502, Ser506, Ser510), homologous desensitization seems to involve the phosphorylation of GC-A at Ser487, a newly identified site of phosphorylation. The identification and further characterization of the specific mechanisms involved in the downregulation of GC-A responsiveness to ANP may have important pathophysiological implications.

Topics: Amino Acid Sequence; Animals; Atrial Natriuretic Factor; Cardiomegaly; Catalytic Domain; Cell Line; Cyclic GMP; Guanylate Cyclase; Heart Failure; Humans; Kidney; Natriuretic Peptide, Brain; Oligopeptides; Peptides; Phosphopeptides; Phosphorylation; Rats; Receptors, Atrial Natriuretic Factor; Second Messenger Systems

Both natriuretic peptides and nitric oxide may be protective in cardiac hypertrophy, although their functional effects are diminished in hypertrophy. Hypoxia inducible factor-1 (HIF-1) may also protect in cardiac hypertrophy. We hypothesized that upregulation of HIF-1 would protect the functional effects of cyclic GMP (cGMP) signaling in hypertrophied ventricular myocytes.. A cardiac hypertrophy model was created in mice by transverse aorta constriction. HIF-1 was increased by deferoxamine (150 mg/kg for 2 days). HIF-1alpha protein levels were examined. Functional parameters were measured (edge detector) on freshly isolated myocytes at baseline and after BNP (brain natriuretic peptide, 10(-8)-10(-7)M) or CNP (C-type natriuretic peptide, 10(-8)-10(-7)M) or SNAP (S-nitroso-N-acetyl-penicillamine, a nitric oxide donor, 10(-6)-10(-5)M) followed by KT5823 (a cyclic GMP-dependent protein kinase (PKG) inhibitor, 10(-6)M). We also determined PKG expression levels and kinase activity.. We found that under control conditions, BNP (-24%), CNP (-22%) and SNAP (-23%) reduced myocyte shortening, while KT5823 partially restored function. Deferoxamine treated control myocytes responded similarly. Baseline function was reduced in the myocytes from hypertrophied heart. BNP, CNP, SNAP and KT5823 also had no significant effects on function in these myocytes. Deferoxamine restored the negative functional effects of BNP (-22%), CNP (-18%) and SNAP (-19%) in hypertrophic cardiac myocytes and KT5823 partially reversed this effect. Additionally, deferoxamine maintained PKG expression levels and activity in hypertrophied heart.. Our results indicated that the HIF-1 protected the functional effects of cGMP signaling in cardiac hypertrophy through preservation of PKG.

Topics: Animals; Carbazoles; Cardiomegaly; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Deferoxamine; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Hypoxia-Inducible Factor 1; Hypoxia-Inducible Factor 1, alpha Subunit; Male; Mice; Mice, Inbred C57BL; Myocytes, Cardiac; Natriuretic Peptide, Brain; Natriuretic Peptide, C-Type; Nitric Oxide; S-Nitroso-N-Acetylpenicillamine; Signal Transduction; Up-Regulation

The objective of this study was to assess a possible link between microalbuminuria (MA), a major risk factor of the cardiorenal syndrome and the brain natriuretic peptide (BNP), a marker of cardiac hypertrophy. Two kidney-one clip (2K-1C) renovascular hypertension was induced in 24 male Wistar rats (weighing 220-250 g). Rats were randomized into four groups for 8 weeks: Sham, not treated; Bos, treated with bosentan; Cap, treated with captopril; Bos/Cap, treated with both drugs. Blood pressure, plasma BNP and transforming growth factor beta1 (TGF-β1) concentrations, microalbuminuria and creatininemia as well as cardiac mass, BNP, alpha- and beta-myosin heavy chain (MHC) gene expression and kidney histology were determined. Following stenosis, Sham rats developed hypertension (p < 0.001), an increase in BNP (p < 0.05) and TGF-β1 (p < 0.005) concentrations, creatinine levels (p < 0.001), and urinary albumin (p < 0.001). Under drug treatment, decreases in blood pressure (p < 0.001), creatinine levels (p < 0.05), plasma TGF-β1 (p < 0.005) and BNP (p < 0.05) concentrations, were concomitant with the absence of MA which was significantly correlated with reductions in cardiac mass (p < 0.05) and hypertrophy markers (BNP and β-MHC gene expression) (p < 0.005) as well as in renal fibrosis. These findings suggest a potential link between microalbuminuria evolution and BNP as well as a possible effect of microalbuminuria-lowering therapy on halting the progression, or even inducing the regression of cardiac hypertrophy.

Topics: Albuminuria; Animals; Blood Pressure; Cardiomegaly; Creatinine; Hypertension; Hypertension, Renovascular; Male; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley; Transforming Growth Factor beta1

The β(2)-selective adrenoreceptor agonist clenbuterol promotes both skeletal and cardiac muscle hypertrophy and is undergoing clinical trials in the treatment of muscle wasting and heart failure. We have previously demonstrated that clenbuterol induces a mild physiological ventricular hypertrophy in vivo with normal contractile function and without induction of α-skeletal muscle actin (αSkA), a marker of pathological hypertrophy. The mechanisms of this response remain poorly defined. In this study, we examine the direct action of clenbuterol on cardiocyte cultures in vitro. Clenbuterol treatment resulted in increased cell size of cardiac myocytes with increased protein accumulation and myofibrillar organisation characteristic of hypertrophic growth. Real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) revealed elevated mRNA expression of ANP and brain natriuretic peptide (BNP) but without change in αSkA, consistent with physiological hypertrophic growth. Clenbuterol-treated cultures also showed elevated insulin-like growth factor I (IGF-1) mRNA and activation of the protein kinase Akt. Addition of either IGF-1 receptor-blocking antibodies or LY294002 in order to inhibit phosphatidylinositol 3-kinase, a downstream effector of the IGF-1 receptor, inhibited the hypertrophic response indicating that IGF-1 signalling is required. IGF-1 expression localised primarily to the minor population of cardiac fibroblasts present in the cardiocyte cultures. Together these data show that clenbuterol acts to induce mild cardiac hypertrophy in cardiac myocytes via paracrine signalling involving fibroblast-derived IGF-1.

Topics: Actins; Adrenergic beta-2 Receptor Agonists; Animals; Animals, Newborn; Atrial Natriuretic Factor; Blotting, Western; Cardiomegaly; Cell Size; Cells, Cultured; Clenbuterol; Fibroblasts; Gene Expression Regulation; Insulin-Like Growth Factor I; Myocytes, Cardiac; Natriuretic Peptide, Brain; Paracrine Communication; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Time Factors; Transfection

Heparin cofactor II (HCII), a serine protease inhibitor, inhibits tissue thrombin action after binding with dermatan sulfate proteoglycans in the extracellular matrix of the vascular system. We previously reported that heterozygous HCII-deficient (HCII(+/-)) humans and mice demonstrate acceleration of vascular remodeling, including atherosclerosis. However, the action of HCII on cardiac remodeling never has been determined. HCII(+/+) and HCII(+/-) mice at age 25 weeks were infused with angiotensin II (Ang II; 2.0 mg/kg/d) for 2 weeks by an osmotic mini-pump. Echocardiography revealed acceleration of cardiac concentric remodeling in HCII(+/-) mice and larger left atrial volume in HCII(+/-) mice than in HCII(+/+) mice. Histopathologic studies showed more prominent interstitial fibrosis in both the left atrium and left ventricle in HCII(+/-) mice than in HCII(+/+) mice. Daily urinary excretion of 8-hydroxy-2'-deoxyguanosine, a parameter of oxidative stress, and dihydroethidium-positive spots, indicating superoxide production in the myocardium, were markedly increased in Ang II-treated HCII(+/-) mice compared to those in HCII(+/+) mice. Cardiac gene expression levels of atrial natriuretic peptides and brain natriuretic peptides, members of the natriuretic peptide family, Nox 4, Rac-1, and p67(phox) as components of NAD(P)H oxidase, and transforming growth factor-beta1 and procollagen III were more augmented in HCII(+/-) mice than in HCII(+/+) mice. However, administration of human HCII protein attenuated all of those abnormalities in Ang II-treated HCII(+/-) mice. Moreover, human HCII protein supplementation almost abolished cardiac fibrosis in Ang II-treated HCII(+/+) mice. The results indicate that HCII has a protective role against Ang II-induced cardiac remodeling through suppression of the NAD(P)H oxidase-transforming growth factor-beta1 pathway.

Topics: Analysis of Variance; Angiotensin II; Animals; Atrial Natriuretic Factor; Cardiomegaly; Echocardiography; Fibrosis; Heart Atria; Heparin Cofactor II; Mice; Mice, Transgenic; Myocardium; Natriuretic Peptide, Brain; Oxidative Stress; Transforming Growth Factor beta1; Ventricular Remodeling

Corin is a serine protease that cleaves pro-atrial and pro-B-type natriuretic peptides into biologically active hormones. The relationship between soluble plasma corin levels, plasma natriuretic peptide levels, myocardial structure and performance, and long-term clinical outcomes in the setting of chronic systolic heart failure has not been described.. In 126 patients with chronic systolic heart failure (left ventricular ejection fraction

Topics: Adult; Aged; Biomarkers; Cardiomegaly; Chronic Disease; Cohort Studies; Female; Follow-Up Studies; Heart Failure, Systolic; Humans; Male; Middle Aged; Natriuretic Peptide, Brain; Natriuretic Peptides; Prognosis; Prospective Studies; Serine Endopeptidases

An increasing amount of evidence demonstrates the beneficial role of oxytocin (OT) in the cardiovascular system. Similar actions are attributed to genistein, an isoflavonic phytoestrogen. The treatment with genistein activates the OT system in the aorta of ovariectomized (OVX) Sprague-Dawley (SD) rats. The objective of this study was to determine the effects of low doses of genistein on the OT-induced effects in rat hypertension. The hypothesis tested was that treatment of OVX spontaneously hypertensive rats (SHRs) with genistein improves heart structure and heart work through a mechanism involving the specific OT receptor (OTR). OVX SHRs or SD rats were treated with genistein (in microg/g body wt sc, 10 days) in the presence or absence of an OT antagonist (OTA) [d(CH(2))(5), Tyr(Me)(2), Orn(8)]-vasotocin or a nonspecific estrogen receptor antagonist (ICI-182780). Vehicle-treated OVX rats served as controls. RT-PCR and Western blot analysis demonstrated that left ventricular (LV) OTR, downregulated by ovariectomy, increased in response to genistein. In SHRs or SD rats, this effect was blocked by OTA or ICI-182780 administration. The OTR was mainly localized in microvessels expressing the CD31 marker and colocalized with endothelial nitric oxide synthase. In SHRs, the genistein-stimulated OTR increases were associated with improved fractional shortening, decreased blood pressure (12 mmHg), decreased heart weight-to-body weight ratio, decreased fibrosis, and lowered brain natriuretic peptide in the LV. The prominent finding of the study is the detrimental effect of OTA treatment on the LV of SHRs. OTA treatment of OVX SHRs resulted in a dramatic worsening of ejection fractions and an augmented fibrosis. In conclusion, these results demonstrate that cardiac OTRs are involved in the regulation of cardiac function of OVX SHRs. The decreases of OTRs may contribute to cardiac pathology following menopause.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Disease Models, Animal; Dose-Response Relationship, Drug; Estradiol; Estrogen Antagonists; Female; Fibrosis; Fulvestrant; Genistein; Hypertension; Myocardial Contraction; Myocardium; Natriuretic Peptide, Brain; Ovariectomy; Rats; Rats, Inbred SHR; Rats, Sprague-Dawley; Receptors, Estrogen; Receptors, Oxytocin; RNA, Messenger; Vasotocin; Ventricular Function, Left; Ventricular Pressure; Ventricular Remodeling

To observe the effect of Qi-Benefiting, Blood-Activating Recipe on the different pathologic stage of myocardial hypertrophy induced by ISO in rats.. Myocardial hypertrophy rats were induced by isoproterenol, and treated with Qi-Benefiting, Blood-Activating Recipe for 5,10 and 15 weeks, hemodynamic parameters, LVMI, HMI were determined, ANP and BNP were analysed.. Qi-Benefiting, Blood-Activating Recipe could increase cardiac output and improve hemodynamic parameters all after 5, 10 and 15 weeks' treatment (P<0.05). It could decrease the contents of ANP and BNP after 5, 10 and 15 weeks' treatment (P<0.05). Qi-Benefiting, Blood-Activating Recipe could significantly decrease the levels of HWI and LVMI after 5, 10 and 15 weeks' treatment (P<0.05).. Qi-Benefiting, Blood-Activating Recipe can significant improve hemodynamic status, increase cardiac output and decrease the level of neurohormonal factors.

Topics: Animals; Atrial Natriuretic Factor; Cardiac Output; Cardiomegaly; Drug Combinations; Drugs, Chinese Herbal; Isoproterenol; Male; Myocardium; Natriuretic Peptide, Brain; Plants, Medicinal; Qi; Random Allocation; Rats; Rats, Sprague-Dawley; Ventricular Function, Left

Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and extracellular signal-regulated kinase (ERK) have pivotal roles in endothelin-1 (ET-1)-induced cardiomyocyte hypertrophy. We here tested whether a novel CaM antagonist, DY-9760e inhibits ET-1-induced hypertrophy through inhibition of CaMKII and ERK activities. We first confirmed that Ca(2+) oscillation induced by ET-1 treatment elicits transient activation of CaMKII and ERK in cultured cardiomyocytes. DY-9760e treatment with 3 microM totally and partially inhibited the ET-1-induced CaMKII and ERK activation, respectively. The ET-1-induced ERK activation was also partially blocked by a CaMKII inhibitor, KN93. To confirm involvement of CaMKII activity in the ERK activation by ET-1 and A23187, cultured cardiomyocytes were transfected with a constitutively active CaMKII. The transfection with the active CaMKII elicited ERK activation in cultured cardiomyocytes and cotransfection with dominant negative CaMKII eliminated its ERK activation. Consistent with inhibitory actions of DY-9760e on the ET-1-induced CaMKII and ERK activation, induction of hypertrophy-related genes including atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) was significantly inhibited by DY-9760e treatment. Combination treatment with DY-9760e and U0126, a MEK inhibitor, totally blocked the ET-1-induced ANP and BNP expression. DY-9760e treatment (3 microM) significantly inhibited the ET-1-induced hypertrophy and combination treatment with DY-9760e and U0126 totally blocked the ET-1-induced hypertrophy in cultured cardiomyocytes. These results suggest that DY-9760e elicits antihypertrophic action on ET-1-induced cardiac hypertrophy through inhibition of CaMKII and ERK activation and that CaMKII activity in part mediates ET-1-induced ERK activation.

Topics: Animals; Animals, Newborn; Atrial Natriuretic Factor; Benzylamines; Butadienes; Calcimycin; Calcium Signaling; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Cardiomegaly; Cell Proliferation; Cell Size; Cells, Cultured; DNA Replication; Endothelin-1; Extracellular Signal-Regulated MAP Kinases; Indazoles; Ionophores; Myocytes, Cardiac; Natriuretic Peptide, Brain; Nitriles; Phosphorylation; Protein Kinase Inhibitors; Rats; Rats, Wistar; RNA, Messenger; Sulfonamides; Time Factors; Transfection

We investigated cardiac hypertrophy elicited by rosiglitazone treatment at the level of protein synthesis/degradation, mTOR, MAPK and AMPK signalling pathways, cardiac function and aspects of carbohydrate/lipid metabolism. Hearts of rats treated or not with rosiglitazone (15 mg/kg day) for 21 days were evaluated for gene expression, protein synthesis, proteasome and calpain activities, signalling pathways, and function by echocardiography. Rosiglitazone induced eccentric heart hypertrophy associated with increased expression of ANP, BNP, collagen I and III and fibronectin, reduced heart rate and increased stroke volume. Rosiglitazone robustly increased heart glycogen content ( approximately 400%), an effect associated with increases in glycogenin and UDPG-PPL mRNA levels and glucose uptake, and a reduction in glycogen phosphorylase expression and activity. Cardiac triglyceride content, lipoprotein lipase activity and mRNA levels of enzymes involved in fatty acid oxidation were also reduced by the agonist. Rosiglitazone-induced cardiac hypertrophy was associated with an increase in myofibrillar protein content and turnover (increased synthesis and an enhancement of calpain-mediated myofibrillar degradation). In contrast, 26S beta5 chymotryptic proteasome activity and mRNA levels of 20S beta2 and beta5 and 19S RPN 2 proteasome subunits along with the ubiquitin ligases atrogin and CHIP were all reduced by rosiglitazone. These morphological and biochemical changes were associated with marked activation of the key growth-promoting mTOR signalling pathway, whose pharmacological inhibition with rapamycin completely blocked cardiac hypertrophy induced by rosiglitazone. The study demonstrates that both arms of protein balance are involved in rosiglitazone-induced cardiac hypertrophy, and establishes the mTOR pathway as a novel important mediator therein.

Topics: Animals; Atrial Natriuretic Factor; Blotting, Western; Body Weight; Cardiomegaly; Eating; Echocardiography; Glucosyltransferases; Glycogen; Glycogen Phosphorylase; Glycogen Synthase; Glycoproteins; Hemodynamics; Hypoglycemic Agents; Lipoprotein Lipase; Male; Myofibrils; Natriuretic Peptide, Brain; Proteasome Endopeptidase Complex; Protein Kinases; Rats; Rats, Sprague-Dawley; Rosiglitazone; Thiazolidinediones; TOR Serine-Threonine Kinases; UTP-Glucose-1-Phosphate Uridylyltransferase

1. Additive beneficial effects on cardiovascular disease have been reported for amlodipine and atorvastatin. However, it is still unclear whether the combination of amlodipine and atorvastatin has additive beneficial effects on the regression of advanced cardiac hypertrophy in hypertension. In the present study, the effects of the drug combination on advanced cardiac hypertrophy were investigated in elderly spontaneously hypertensive rats (SHR). 2. Elderly SHR (36 weeks old) were randomly allocated into four groups of 12: (i) a vehicle-treated control group; (ii) an amlodipine (10 mg/kg per day)-treated group; (iii) an atorvastatin (10 mg/kg per day)-treated group; and (iv) a group treated with a combination of amlodipine and atorvastatin (both at 10 mg/kg per day). Drugs were administered by oral gavage every morning for a period of 12 weeks before hearts were harvested for analysis. 3. Combined administration of amlodipine and atorvastatin significantly suppressed cardiomyocyte hypertrophy, interstitial fibrosis and upregulation of hypertrophic and profibrotic genes, and also improved left ventricular diastolic dysfunction to a greater extent than did amlodipine monotherapy. Further beneficial effects of combination therapy on advanced cardiac hypertrophy were associated with a greater reduction of NADPH oxidase-mediated increases in cardiac reactive oxygen species (ROS), rather than decreased blood pressure and serum cholesterol levels. 4. To elucidate the underlying molecular mechanisms, we examined cardiovascular NADPH oxidase subunits and found that amlodipine clearly attenuated the expression of p47(phox) and p40(phox) and slightly but significantly reduced p22(phox) and Rac-1 levels in heart tissue. Combination treatment with amlodipine plus atorvastatin led to a further reduction in p22(phox), p47(phox) and Rac-1 protein levels compared with amlodipine alone. 5. In conclusion, combined amlodipine and atorvastatin treatment has a greater beneficial effect on advanced cardiac hypertrophy compared with amlodipine monotherapy. The benefits are likely to be related to the additive effects of the drugs on the suppression of NADPH oxidase-mediated ROS generation.

Topics: Aging; Amlodipine; Animals; Anticholesteremic Agents; Antihypertensive Agents; Atorvastatin; Cardiomegaly; Drug Synergism; Drug Therapy, Combination; Fibrosis; Heart Failure, Diastolic; Hemodynamics; Heptanoic Acids; Myocytes, Cardiac; NADPH Oxidases; Natriuretic Peptide, Brain; Oxidative Stress; Pyrroles; Random Allocation; Rats; Rats, Inbred SHR; Reactive Oxygen Species; Superoxide Dismutase; Ventricular Dysfunction, Left

Cardiac energy metabolism is a determinant of the response to hypertrophic stimuli. To investigate how it responds to physiological or pathological stimuli, we compared the energetic status in models of hypertrophy induced by physiological stimuli (pregnancy or treadmill running) and by pathological stimulus (spontaneously hypertensive rats, SHR) in 15 week-old female rats, leading to a 10% cardiac hypertrophy. Late stage of compensated hypertrophy was also studied in 25 week-old SHR (35% of hypertrophy). Markers of cardiac remodelling did not follow a unique pattern of expression: in trained rats, only ANF was increased; in gravid rats, calcineurin activation and BNP expression were reduced while beta-MHC expression was enhanced; all markers were clearly up-regulated in 25 week-old SHR. Respiration of permeabilized fibers revealed a 17% increase in oxidative capacity in trained rats only. Mitochondrial enzyme activities, expression of the master regulator PGC-1alpha and mitochondrial transcription factor A, and content of mitochondrial DNA were not consistently changed, suggesting that compensated hypertrophy does not involve alterations of mitochondrial biogenesis. Mitochondrial fatty acid utilization tended to increase in trained rats and decreased by 14% in 15 week-old SHR. Expression of markers of lipid oxidation, PPARalpha and its down-stream targets MCAD and CPTI, was up-regulated after training and tended to decrease in gravid and 15 week-old SHR rats. Taken together these results show that there is no univocal pattern of cardiac adaptation in response to physiological or pathological hypertrophic stimuli, suggesting that other factors could play a role in determining adaptation of energy metabolism to increased workload.

Topics: Acyl-CoA Dehydrogenase; Animals; Atrial Natriuretic Factor; Cardiomegaly; Carnitine O-Palmitoyltransferase; Disease Models, Animal; Energy Metabolism; Female; Glucose Transporter Type 4; In Vitro Techniques; Intracellular Signaling Peptides and Proteins; Myosin Heavy Chains; Natriuretic Peptide, Brain; Organ Size; Oxygen Consumption; Polymerase Chain Reaction; PPAR alpha; Pregnancy; Protein Serine-Threonine Kinases; Pyruvate Dehydrogenase Acetyl-Transferring Kinase; Rats

To compare the effects of enzyme replacement therapy (ERT) on cardiac performance in symptomatic and symptom-free infants with Pompe disease.. Patients diagnosed between 1983 and 2008 were identified. Before the initiation of ERT, systolic dysfunction appeared only in patients > or = 5 months; thus we used this cut-point in age to divide clinically symptomatic patients into early and late treatment groups (Clin-E and Clin-L). Newborn screening (NBS) identified symptom-free patients.. Among a total of 40 patients, 14 received ERT: 5 in the Clin-L, 4 in the Clin-E, and 5 in the NBS groups. All patients showed cardiomegaly, hypertrophic myocardium, and elevated B-type natriuretic peptide (measured in the Clin-E and NBS groups). ERT improved the survival and outcomes. Regressed myocardial hypertrophy and lowered B-type natriuretic peptide level occurred after 1 to 6 months of ERT. Nonetheless, there were 2 deaths and 2 survivors requiring ventilator support in the Clin-L group. Despite the regressed QRS voltage and shortened QT dispersion, life-threatening arrhythmias were still observed in 3, but none in the NBS group.. ERT may restore the cardiac function in both symptomatic and symptom-free patients, but the beneficial effect may be unpredictable if given after the age of 5 months.

Topics: alpha-Glucosidases; Cardiomegaly; Electrocardiography; Glycogen Storage Disease Type II; Humans; Hypertrophy, Left Ventricular; Infant; Natriuretic Peptide, Brain; Prospective Studies; Stroke Volume; Tachycardia

Cardiac atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) modulate blood pressure and volume by activation of the receptor guanylyl cyclase-A (GC-A) and subsequent intracellular cGMP formation. Here we report what we believe to be a novel function of these peptides as paracrine regulators of vascular regeneration. In mice with systemic deletion of the GC-A gene, vascular regeneration in response to critical hind limb ischemia was severely impaired. Similar attenuation of ischemic angiogenesis was observed in mice with conditional, endothelial cell-restricted GC-A deletion (here termed EC GC-A KO mice). In contrast, smooth muscle cell-restricted GC-A ablation did not affect ischemic neovascularization. Immunohistochemistry and RT-PCR revealed BNP expression in activated satellite cells within the ischemic muscle, suggesting that local BNP elicits protective endothelial effects. Since within the heart, BNP is mainly induced in cardiomyocytes by mechanical load, we investigated whether the natriuretic peptide/GC-A system also regulates angiogenesis accompanying load-induced cardiac hypertrophy. EC GC-A KO hearts showed diminished angiogenesis, mild fibrosis, and diastolic dysfunction. In vitro BNP/GC-A stimulated proliferation and migration of cultured microvascular endothelia by activating cGMP-dependent protein kinase I and phosphorylating vasodilator-stimulated phosphoprotein and p38 MAPK. We therefore conclude that BNP, produced by activated satellite cells within ischemic skeletal muscle or by cardiomyocytes in response to pressure load, regulates the regeneration of neighboring endothelia via GC-A. This paracrine communication might be critically involved in coordinating muscle regeneration/hypertrophy and angiogenesis.

Topics: Animals; Cardiomegaly; Cell Adhesion Molecules; Cell Movement; Cell Proliferation; Cells, Cultured; Coronary Vessels; Endothelial Cells; Female; Guanylate Cyclase; Hindlimb; Ischemia; Male; Mice; Microfilament Proteins; Natriuretic Peptide, Brain; Neovascularization, Physiologic; p38 Mitogen-Activated Protein Kinases; Phosphoproteins; Reperfusion; RNA, Messenger

The heart adapts to an increased workload through the activation of a hypertrophic response within the cardiac ventricles. This response is characterized by both an increase in the size of the individual cardiomyocytes and an induction of a panel of genes normally expressed in the embryonic and neonatal ventricle, such as atrial natriuretic peptide (ANP). ANP and brain natriuretic peptide (BNP) exert their biological actions through activation of the natriuretic peptide receptor-1 (Npr1). The current study examined mice lacking Npr1 (Npr1(-/-)) activity and investigated the effects of the absence of Npr1 signaling during cardiac development on embryo viability, cardiac structure and gene and protein expression. Npr1(-/-)embryos were collected at embryonic day (ED) 12.5, 15.5 and neonatal day 1 (ND 1). Npr1(-/-)embryos occurred at the expected Mendelian frequency at ED 12.5, but knockout numbers were significantly decreased at ED 15.5 and ND 1. There was no indication of cardiac structural abnormalities in surviving embryos. However, Npr1(-/-)embryos exhibited cardiac enlargement (without fibrosis) from ED 15.5 as well as significantly increased ANP mRNA and protein expression compared to wild-type (WT) mice, but no concomitant increase in expression of the hypertrophy-related transcription factors, Mef2A, Mef2C, GATA-4, GATA-6 or serum response factor (SRF). However, there was a significant decrease in Connexin-43 (Cx43) gene and protein expression at mid-gestation in Npr1(-/-)embryos. Our findings suggest that the mechanism by which natriuretic peptide signaling influences cardiac development in Npr1(-/-) mice is distinct from that seen during the development of pathological cardiac hypertrophy and fibrosis. The decreased viability of Npr1(-/-)embryos may result from a combination of cardiomegaly and dysregulated Cx43 protein affecting cardiac contractility.

Topics: Animals; Atrial Natriuretic Factor; Blood Pressure; Blotting, Western; Cardiomegaly; Connexin 43; Embryo, Mammalian; Female; Gene Expression Regulation, Developmental; Heart; Immunoenzyme Techniques; Male; Mice; Mice, Knockout; Natriuretic Peptide, Brain; Receptors, Atrial Natriuretic Factor; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Survival Rate; Transcription Factors

Mycobacterium tuberculosis is the most frequently identified mycobacterium in the bronchoalveolar lavage fluid (BALF) of immunocompetent patients. Lung infections due to non-tuberculous mycobacteria (NTM) are rare in such patients and then often occur in the context of pre-existing chronic lung disease. We report the case of an immunocompetent 85-year-old woman without pre-existing lung disease in whom M. abscessus was recovered from BALF. Cytological examination of the BALF revealed an increased number of neutrophils and some acid-fast bacilli, all located within neutrophil cytoplasm. This case report contributes a cytological description of BALF in the context of M. abscessus infection, which is poorly detailed in the literature.

Topics: Aged, 80 and over; Bronchoalveolar Lavage Fluid; C-Reactive Protein; Cardiomegaly; Diagnosis, Differential; Female; Humans; Immunocompetence; Mycobacterium; Mycobacterium Infections; Natriuretic Peptide, Brain; Neutrophils; Radiography, Thoracic; Tomography, X-Ray Computed

An understanding of the cellular physiology of cardiac myocytes (MCs) and non-myocytes (NMCs) may help to explain the mechanisms underlying cardiac hypertrophy. Despite numerous studies using MC/NMC co-culture systems, it is difficult to precisely evaluate the influence of each cell type because of the inherent cellular heterogeneity of such a system. Here we developed a co-culture system using Wistar rat neonatal MCs and NMCs isolated by discontinuous Percoll gradient and adhesion separation methods and cultured on either side of insert well membranes. Co-culture of MCs and NMCs resulted in significant increases in [3H]-leucine incorporation by MCs, in the amount of protein synthesized by MCs, and in the secretion of natriuretic peptides, while the addition of MCs to NMC cultures significantly reduced [3H]-thymidine incorporation by NMCs. Interestingly, the percentage of the brain natriuretic peptide (BNP) component of total natriuretic peptide secreted (atrial natriuretic peptide+BNP) increased as the number of NMCs placed in the MC/NMC co-culture system increased. However, MCs did not affect production of angiotensin II (Ang II) by NMCs or secretion of endothelin-1 and transforming growth factor-beta1 into the MC/NMC co-culture system. This finding was supported by the anti-hypertrophic and anti-fibrotic actions of RNH6270, an active form of olmesartan, on MCs in the MC/NMC co-culture system and on NMCs that may synthesize Ang II in the heart. The present data indicate that cardiac fibrosis may not only facilitate MC hypertrophy (possibly through the local angiotensin system) but may also change particular pathophysiological properties of MCs, such as the secretory pattern of natriuretic peptides.

Topics: Angiotensin II; Angiotensinogen; Animals; Animals, Newborn; Atrial Natriuretic Factor; Cardiomegaly; Cell Separation; Cells, Cultured; Coculture Techniques; Diuretics, Osmotic; Endothelin-1; Fibrosis; Leucine; Mannitol; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Peptidyl-Dipeptidase A; Rats; Rats, Wistar; Receptors, Angiotensin; Renin; Thymidine; Transforming Growth Factor beta1; Tritium

Corin is a cardiac serine protease that acts as the pro-atrial natriuretic peptide (ANP) convertase. Recently, 2 single-nucleotide polymorphisms (SNPs) (T555I and Q568P) in the human corin gene have been identified in genetic epidemiological studies. The minor I555/P568 allele, which is more common in African Americans, is associated with hypertension and cardiac hypertrophy. In this study, we examined the effect of T555I and Q568P amino acid substitutions on corin function. We found that corin frizzled-like domain 2, where T555I/Q568P substitutions occur, was required for efficient pro-ANP processing in functional assays. Mutant corin lacking this domain had 30+/-5% (P<0.01) activity compared to that of wild type. Similarly, corin variant T555I/Q568P had a reduced (38+/-7%, P<0.01) pro-ANP processing activity compared to that of wild type. The variant also exhibited a low activity (44+/-15%, P<0.05) in processing pro-brain natriuretic peptide (BNP). We next examined the biochemical basis for the loss of activity in T555I/Q568P variant and found that the zymogen activation of the corin variant was impaired significantly, as indicated by the absence of the activated protease domain fragment. This finding was confirmed in human embryonic kidney (HEK)293 cells and murine HL-1 cardiomyocytes. Thus, our results show that the corin gene SNPs associated with hypertension and cardiac hypertrophy impair corin zymogen activation and natriuretic peptide processing activity. Our data suggest that corin deficiency may be an important mechanism in hypertensive and heart diseases.

Topics: Atrial Natriuretic Factor; Cardiomegaly; Cell Line; Enzyme Precursors; Genetic Variation; Humans; Hypertension; Kidney; Membrane Proteins; Mutagenesis; Natriuretic Peptide, Brain; Natriuretic Peptides; Polymorphism, Single Nucleotide; Protein Structure, Tertiary; Serine Endopeptidases; Substrate Specificity; Transfection

The mammalian target of rapamycin complex 1 (mTORC1), a key regulator of protein synthesis, growth and proliferation in mammalian cells, is implicated in the development of cardiac hypertrophy. Ras homolog enriched in brain (Rheb) positively regulates mTORC1. We have studied whether Rheb is sufficient to activate mTOR signaling and promote protein synthesis and cardiac hypertrophy in adult rat ventricular cardiomyocytes (ARVC). Rheb was overexpressed via an adenoviral vector in isolated ARVC. Overexpression of Rheb in ARVC activated mTORC1 signaling, several components of the translational machinery and stimulated protein synthesis. Our direct visualization approach to determine ARVC size revealed that overexpression of Rheb also induced cell growth and indeed did so to similar extent to the hypertrophic agent, phenylephrine (PE). Despite potent activation of mTORC1 signaling, overexpression of Rheb did not induce expression of the cardiac hypertrophic marker mRNAs for brain natriuretic peptide and atrial natriuretic factor, while PE treatment did markedly increase their expression. All the effects of Rheb were blocked by rapamycin, confirming their dependence on mTORC1 signaling. Our findings reveal that Rheb itself can activate both protein synthesis and cell growth in ARVC and demonstrate the key role played by mTORC1 in the growth of cardiomyocytes.

Topics: Adenoviridae; Animals; Anti-Bacterial Agents; Atrial Natriuretic Factor; Biomarkers; Cardiomegaly; Cardiotonic Agents; Cell Proliferation; Cell Size; Cells, Cultured; Genetic Vectors; Heart Ventricles; Male; Monomeric GTP-Binding Proteins; Myocytes, Cardiac; Natriuretic Peptide, Brain; Neuropeptides; Phenylephrine; Protein Biosynthesis; Protein Kinases; Ras Homolog Enriched in Brain Protein; Rats; Rats, Sprague-Dawley; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The liganded vitamin D receptor (VDR) is thought to play an important role in controlling cardiac function. Specifically, this system has been implicated as playing an antihypertrophic role in the heart. Despite this, studies of VDR in the heart have been limited in number and scope. In the present study, we used a combination of real-time polymerase chain reaction, Western blot analysis, immunofluorescence, and transient transfection analysis to document the presence of functional VDR in both the myocytes and fibroblasts of the heart, as well as in the intact ventricular myocardium. We also demonstrated the presence of 1-alpha-hydroxylase and 24-hydroxylase in the heart, 2 enzymes involved in the synthesis and metabolism of 1,25 dihydroxyvitamin D. VDR is shown to interact directly with the human B-type natriuretic peptide gene promoter, a surrogate marker of the transcriptional response to hypertrophy. Of note, induction of myocyte hypertrophy either in vitro or in vivo leads to an increase in VDR mRNA and protein levels. Collectively, these findings suggest that the key components required for a functional 1,25 dihydroxyvitamin D-dependent signaling system are present in the heart and that this putatively antihypertrophic system is amplified in the setting of cardiac hypertrophy.

Topics: Animals; Cardiomegaly; Cells, Cultured; Fibroblasts; Gene Expression; Humans; Luciferases; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phosphatidylethanolamines; Rats; Rats, Sprague-Dawley; Rats, Wistar; Receptors, Calcitriol; Signal Transduction; Vitamin D

Several biological pathways are activated concomitantly during left ventricular (LV) remodeling. However, the relative contribution of circulating biomarkers representing these distinct pathways to LV geometry is unclear.. We evaluated 2119 Framingham Offspring Study participants (mean age, 57 years; 57% women) who underwent measurements of biomarkers of inflammation (C-reactive protein), hemostasis (fibrinogen and plasminogen activator inhibitor-1), neurohormonal activation (B-type natriuretic peptide), and renin-angiotensin-aldosterone system (aldosterone and renin modeled as a ratio [ARR]) and echocardiography at a routine examination. LV geometry was defined on the basis of sex-specific distributions of LV mass (LVM) and relative wall thickness (RWT): normal (LVM and RWT <80th percentile), concentric remodeling (LVM <80th percentile but RWT >or=80th percentile), eccentric hypertrophy (LVM >or=80th percentile but RWT <80th percentile), and concentric hypertrophy (LVM and RWT >or=80th percentile). We related the biomarker panel to LV geometry using polytomous logistic regression adjusting for clinical covariates and used backwards elimination to identify a parsimonious set of biomarkers associated with LV geometry. Modeled individually, C-reactive protein, fibrinogen, plasminogen activator inhibitor-1, and ARR were related to LV geometry (P<0.01). In multivariable analyses, the biomarker panel was significantly related to altered LV geometry (P<0.0001). On backwards elimination, logARR alone was significantly and positively associated with eccentric (odds ratio per SD increment, 1.20; 95% confidence interval, 1.05 to 1.37) and concentric LV hypertrophy (odds ratio per SD increment, 1.29; 95% confidence interval, 1.06 to 1.58).. Our cross-sectional observations on a large community-based sample identified ARR as a key correlate of concentric and eccentric LV hypertrophy, consistent with a major role for the renin-angiotensin-aldosterone system in LV remodeling.

Topics: Aldosterone; Biomarkers; C-Reactive Protein; Cardiomegaly; Electrocardiography; Female; Fibrin; Heart Ventricles; Humans; Inflammation; Male; Middle Aged; Natriuretic Peptide, Brain; Plasminogen Activator Inhibitor 1; Regression Analysis; Renin-Angiotensin System; Ultrasonography; Ventricular Function, Left; Ventricular Remodeling

The role of the angiotensin II type 2 (AT2) receptor in cardiac hypertrophy remains controversial. We studied the effects of AT2 receptors on chronic pressure overload-induced cardiac hypertrophy in transgenic mice selectively overexpressing AT2 receptors in ventricular myocytes. Left ventricular (LV) hypertrophy was induced by ascending aorta banding (AS). Transgenic mice overexpressing AT2 (AT2TG-AS) and nontransgenic mice (NTG-AS) were studied after 70 days of aortic banding. Nonbanded NTG mice were used as controls. LV function was determined by catheterization via LV puncture and cardiac magnetic resonance imaging. LV myocyte diameter and interstitial collagen were determined by confocal microscopy. Atrial natriuretic polypeptide (ANP) and brain natriuretic peptide (BNP) were analyzed by Northern blot. Sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA)2, inducible nitric oxide synthase (iNOS), endothelial NOS, ERK1/2, p70S6K, Src-homology 2 domain-containing protein tyrosine phosphatase-1, and protein serine/threonine phosphatase 2A were analyzed by Western blot. LV myocyte diameter and collagen were significantly reduced in AT2TG-AS compared with NTG-AS mice. LV anterior and posterior wall thickness were not different between AT2TG-AS and NTG-AS mice. LV systolic and diastolic dimensions were significantly higher in AT2TG-AS than in NTG-AS mice. LV systolic pressure and end-diastolic pressure were lower in AT2TG-AS than in NTG-AS mice. ANP, BNP, and SERCA2 were not different between AT2TG-AS and NTG-AS mice. Phospholamban (PLB) and the PLB-to-SERCA2 ratio were significantly higher in AT2TG-AS than in NTG-AS mice. iNOS was higher in AT2TG-AS than in NTG-AS mice but not significantly different. Our results indicate that AT2 receptor overexpression modified the pathological hypertrophic response to aortic banding in transgenic mice.

Topics: Animals; Atrial Natriuretic Factor; Blood Pressure; Blotting, Northern; Blotting, Western; Cardiomegaly; Collagen; Hypertension; Male; Mice; Mice, Transgenic; Microscopy, Confocal; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Receptor, Angiotensin, Type 2; RNA, Messenger; Survival Analysis; Ventricular Function, Left

We have shown previously that cyclooxygenase-2 inhibition reduces cardiac hypertrophy and fibrosis postmyocardial infarction (MI) in a mouse model and that prostaglandin E(2) stimulates cardiomyocyte hypertrophy in vitro through its EP(4) receptor. Because the role of cardiac myocyte EP(4) in cardiac function and hypertrophy in vivo is unknown, we generated mice lacking EP(4) only in cardiomyocytes (CM- EP(4) knockout [KO]). Twelve- to 14-week-old mice were evaluated using echocardiography and histology. There were no differences in ejection fraction, myocyte cross-sectional area, and interstitial collagen fraction between KO mice and littermate controls. To test the hypothesis that EP(4) is involved in cardiac remodeling after MI, we induced MI by ligating the left anterior descending coronary artery. Two weeks later, the mice were subjected to echocardiography, and hearts were removed for histology and Western blot. There was no difference in infarct size between KO mice and controls; however, KO mice showed less myocyte cross-sectional area and interstitial collagen fraction than controls. Also, CM-EP4 KO mice had reduced ejection fraction. Because the transcription factor Stat-3 is involved in hypertrophy and protection from ischemic injury, we tested whether it was activated in control and KO mouse hearts after MI. Western blot indicated that Stat-3 was activated in control hearts after MI but not in KO hearts. Thus, CM-EP4 deletion decreased hypertrophy, fibrosis, and activation of Stat-3. However, cardiac function was unexpectedly worsened in these mice. We conclude that cardiac myocyte EP(4) plays a role in hypertrophy via activation of Stat-3, a process that seems to be cardioprotective.

Topics: Animals; Blotting, Western; Cardiomegaly; Echocardiography; Fibrosis; Gene Expression; Heart; Mice; Mice, Knockout; Myocardial Infarction; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Receptors, Prostaglandin E; Receptors, Prostaglandin E, EP4 Subtype; STAT3 Transcription Factor; Stroke Volume; Ventricular Remodeling

The aim of this study was to investigate whether atorvastatin inhibits epidermal growth factor receptor (EGFR) activation in cardiomyocytes in vitro and slows the progression of cardiac remodeling induced by pressure overload in mice. Either atorvastatin (5 mg/kg/day) or vehicle was orally administered to male C57BL/6J mice with transverse aortic constriction (TAC). Physiological parameters were obtained by echocardiography or left ventricular (LV) catheterization, and morphological and molecular parameters of the heart were also examined. Furthermore, cultured neonatal rat cardiomyocytes were studied to clarify the underlying mechanisms. Four weeks after TAC, atorvastatin reduced the heart/body weight and lung/body weight ratios (8.69+/-0.38 to 6.45+/-0.31 mg/g (p<0.001) and 10.89+/-0.68 to 6.61+/-0.39 mg/g (p<0.01) in TAC mice with and without atorvastatin, respectively). Decrease of LV end-diastolic pressure and the time constant of relaxation, increased fractional shortening, downregulation of a disintegrin and metalloproteinase (ADAM)12, ADAM17 and heparin-binding epidermal growth factor genes, and reduction of the activity of EGFR and extracellular signal-regulated kinase (ERK) were observed in the atorvastatin group. Phenylephrine-induced protein synthesis, phosphorylation of EGFR, and activation of ERK in neonatal rat cardiomyocytes were all inhibited by atorvastatin. These findings indicated that atorvastatin ameliorates cardiac remodeling in mice with pressure overload, and its actions are associated with inhibition of the EGFR signaling pathway.

Topics: Animals; Atorvastatin; Cardiomegaly; Disease Progression; ErbB Receptors; Extracellular Signal-Regulated MAP Kinases; Heart Failure; Heparin-binding EGF-like Growth Factor; Heptanoic Acids; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Intercellular Signaling Peptides and Proteins; Male; Mice; Mice, Inbred C57BL; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phosphorylation; Pyrroles; Ventricular Function, Left

Altered regulation of signaling pathways can lead to pathologies including cardiac hypertrophy and heart failure. We report that neonatal and adult cardiomyocytes express chromogranin B (CGB), a Ca(2+) binding protein that modulates Ca(2+) release by the inositol 1,4,5-trisphosphate receptor (InsP(3)R). Using fluorescent Ca(2+) indicator dyes, we found that CGB regulates InsP(3)-dependent Ca(2+) release in response to angiotensin II, an octapeptide hormone that promotes cardiac hypertrophy. ELISA experiments and luciferase reporter assays identified angiotensin II as a potent inducer of brain natriuretic peptide (BNP), a hormone that recently emerged as an important biomarker in cardiovascular disease. CGB was found to regulate angiotensin II-stimulated and basal secretion, expression and promoter activity of BNP that depend on the InsP(3)R. Moreover, we provide evidence that CGB acts via the transcription activity of nuclear factor kappaB in an InsP(3)/Ca(2+)-dependent manner but independent of nuclear factor of activated T cells. In vivo experiments further showed that cardiac hypertrophy induced by angiotensin II, a condition characterized by increased ventricular BNP production, is associated with upregulation of ventricular CGB expression. Overexpression of CGB in cardiomyocytes, in turn, induced the BNP promoter. The evidence presented in this study identifies CGB as a novel regulator of cardiomyocyte InsP(3)/Ca(2+)-dependent signaling, nuclear factor kappaB activity, and BNP production.

Topics: Age Factors; Angiotensin II; Animals; Calcium; Calcium Signaling; Cardiomegaly; Cells, Cultured; Chromogranin B; Inositol 1,4,5-Trisphosphate Receptors; Myocytes, Cardiac; Natriuretic Peptide, Brain; NF-kappa B; NFATC Transcription Factors; Promoter Regions, Genetic; Rats; Transcription, Genetic; Vasoconstrictor Agents

Recent studies suggest that B-type natriuretic peptide (BNP) is an important predictor of cardiac events in hypertensive patients.. The relationship between the plasma BNP level and various clinical parameters was examined in 154 untreated hypertensive patients without heart failure or atrial fibrillation (mean age: 58.0+/-10.7; mean blood pressure: 164.5+/-15.2/99.1+/-9.7 mmHg; mean BNP: 32.7+/-36.7 pg/ml). First, the patients were divided into 2 groups based on BNP: normal (<18.5 pg/ml, mean 9.7+/-5.7, n=69); or elevated (>18.5 pg/ml, mean 51.4+/-40.4, n=85). The elevated BNP group had a significantly greater electrocardiographic voltage index (SV1+RV5; 3.7+/-1.2 vs 3.2+/-0.8 mV, p=0.0029), cardiothoracic ratio/chest radiography (CTR; 49.1 vs 46.9%, p=0.0037), left ventricular mass index (LVMI; 122.2+/-31.7 vs 103.1+/-26.4 g/m2, p=0.0005) and deceleration time (DT; 241+/-39 vs 208+/-30 ms, p=0.0001), as well as a smaller E-wave to A-wave (E/A ratio) (0.80+/-0.22 vs 0.96+/-0.28, p=0.0003), compared with the normal BNP group. There were no significant differences in casual blood pressure, body mass index, serum creatinine and ejection fraction between the 2 groups. Next, the patients were divided into 3 groups based on BNP: normal (<18.5, n=69), moderate (18.5 to 40, mean 27.0+/-5.7, n=43) and high (40<, mean 76.3+/-45.3, n=42). In the high BNP group, most clinical parameters indicated the most severe organ damage compared with other groups, including SV1+RV5, DT and LVMI. In all patients, logarithmic BNP was positively correlated with the age, pulse pressure, SV1+RV5, CTR, ventricular wall thickness, DT, LVMI and negatively correlated with hemoglobin, renin and E/A ratio. Using multiple regression analysis, renin and DT were significantly associated with BNP. No gender differences in the relationship between BNP and clinical parameters were found.. Results suggest that BNP is a useful indicator for the initial assessment of the severity of essential hypertension, detecting both cardiac hypertrophy and diastolic dysfunction, and may also be valuable for risk stratification.

Topics: Adult; Aged; Biomarkers; Blood Pressure; Cardiomegaly; Diastole; Female; Humans; Hypertension; Male; Middle Aged; Natriuretic Peptide, Brain; Predictive Value of Tests; Prevalence; Regression Analysis; Severity of Illness Index

There is increasing evidence showing that inflammation is involved in heart failure. However, heart failure may differ greatly due to different aetiologies. The role of inflammation in hypertensive heart failure, particularly in the early stage of cardiac dysfunction, has not been studied completely. This study aims at finding out whether inflammation is involved in the early stage of heart dysfunction due to hypertension.. Ten spontaneously hypertensive rats (SHR) and ten age-matched Wistar rats were used. Cardiac morphology and function, as well as coronary flow reserve, were examined by echocardiography. mRNAs for cytokines and brain natriuretic peptide were determined by RT-PCR.. The results demonstrate cardiac hypertrophy with increased heart/body weight ratio in SHR. Echocardiographic examination has shown that SHR developed diastolic heart dysfunction as determined by tissue Doppler without decrease in systolic function. In heart biopsies, there were increased mRNA levels for interleukin-6 and brain natriuretic peptide whereas decreased mRNA for interleukin-2, beta adrenergic receptor, interferon and NFkb in SHR as compared to WKY group. Coronary flow remained unchanged in both groups.. SHR developed cardiac hypertrophy complicated with diastolic heart dysfunction with increased expression of brain natriuretic peptide, down-regulation of beta adrenergic receptors and simultaneous up-regulation of IL-6, which indicates active proinflammatory process as, at least partly, underlying mechanism during the early stage when cardiac hypertrophy associated with diastolic dysfunction occurs.

Topics: Animals; Cardiomegaly; Diastole; Disease Models, Animal; Echocardiography; Gene Expression Regulation; Heart Failure; Hypertension; Hypertrophy; Interleukin-6; Myocardium; Natriuretic Peptide, Brain; Rats; Rats, Wistar; Receptors, Adrenergic, beta

Excessive fibrosis contributes to an increase in left ventricular stiffness. The goal of the present study was to investigate the role of connective tissue growth factor (CCN2/CTGF), a profibrotic cytokine of the CCN (Cyr61, CTGF, and Nov) family, and its functional interactions with brain natriuretic peptide (BNP), an antifibrotic peptide, in the development of myocardial fibrosis and diastolic heart failure. Histological examination on endomyocardial biopsy samples from patients without systolic dysfunction revealed that the abundance of CTGF-immunopositive cardiac myocytes was correlated with the excessive interstitial fibrosis and a clinical history of acute pulmonary congestion. In a rat pressure overload cardiac hypertrophy model, CTGF mRNA levels and BNP mRNA were increased in proportion to one another in the myocardium. Interestingly, relative abundance of mRNA for CTGF compared with BNP was positively correlated with diastolic dysfunction, myocardial fibrosis area, and procollagen type 1 mRNA expression. Investigation with conditioned medium and subsequent neutralization experiments using primary cultured cells demonstrated that CTGF secreted by cardiac myocytes induced collagen production in cardiac fibroblasts. Further, G protein-coupled receptor ligands induced expression of the CTGF and BNP genes in cardiac myocytes, whereas aldosterone and transforming growth factor-beta preferentially induced expression of the CTGF gene. Finally, exogenous BNP prevented the production of CTGF in cardiac myocytes. These data suggest that a disproportionate increase in CTGF relative to BNP in cardiac myocytes plays a central role in the induction of excessive myocardial fibrosis and diastolic heart failure.

Topics: Aged; Animals; Cardiomegaly; Cells, Cultured; Connective Tissue Growth Factor; Elasticity; Endomyocardial Fibrosis; Fibrosis; Gene Expression; Humans; Immediate-Early Proteins; Intercellular Signaling Peptides and Proteins; Male; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Nephroblastoma Overexpressed Protein; Rats; Rats, Wistar; RNA, Messenger; Stimulation, Chemical; Stroke Volume; Transcription, Genetic; Ventricular Dysfunction

Myofibrillogenesis regulator-1 (MR-1) augments cardiomyocytes hypertrophy induced by angiotensin II (Ang II) in vitro. However, its roles in cardiac hypertrophy in vivo remain unknown. Here, we investigate whether MR-1 can promote cardiac hypertrophy induced by Ang II in vivo and elucidate the molecular mechanisms of MR-1 on cardiac hypertrophy. We used a model of Ang II-induced cardiac hypertrophy by infusion of Ang II in female mice. In wild-type mice subjected to the Ang II infusion, cardiac hypertrophy developed after 2 weeks. In mice overexpressing human MR-1 (transgenic), however, cardiac hypertrophy was significantly greater than in wild-type mice as estimated by heart weight:body weight ratio, cardiomyocyte area, and echocardiographic measurements, as well as cardiac atrial natriuretic peptide and B-type natriuretic peptide mRNA and protein levels. Our further results showed that cardiac inflammation and fibrosis observed in wild-type Ang II mice were augmented in transgenic Ang II mice. Importantly, increased nuclear factor kappaB activation was significantly increased higher in transgenic mice compared with wild-type mice after 2 weeks of Ang II infusion. In vitro experiments also revealed that overexpression of MR-1 enhanced Ang II-induced nuclear factor kappaB activation, whereas downregulation of MR-1 blocked it in cardiac myocytes. In conclusion, our results suggest that MR-1 plays an aggravative role in the development of cardiac hypertrophy via activation of the nuclear factor kappaB signaling pathway.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Cardiomegaly; Endomyocardial Fibrosis; Female; Gene Expression Regulation; Humans; Mice; Mice, Transgenic; Muscle Proteins; Myocardium; Natriuretic Peptide, Brain; NF-kappa B; RNA, Messenger; Signal Transduction; Vasoconstrictor Agents; Ventricular Remodeling

The identification of valuable markers of sudden cardiac death (SCD) in patients with established HF remains a challenge. We sought to assess the value of clinical, echocardiographic and biochemical variables to predict SCD in a consecutive cohort of patients with heart failure (HF) due to systolic dysfunction.. A cohort of 494 patients with established HF had baseline echocardiographic and NT-proBNP measurements and were followed for 942+/-323 days.. Fifty patients suffered SCD. Independent predictors of SCD were indexed LA size>26 mm/m2 (HR 2.8; 95% CI 1.5-5.0; p=0.0007), NT-proBNP>908 ng/L (HR 3.1; 95% CI 1.5-6.7; p=0.003), history of myocardial infarction (HR 2.3; 95% CI 1.3-4.1; p=0.007), peripheral oedema (HR 2.1; 95% CI 1.1-3.9; p=0.02), and diabetes mellitus (HR 1.9; 95% CI 1.1-3.3; p=0.03). NYHA functional class, left ventricular ejection fraction and glomerular filtration rate were not independent predictors of SCD in this cohort. Notably, the combination of both LA size>26 mm/m2 and NT-proBNP>908 ng/L increased the risk of SCD (HR 4.3; 95% CI 2.5-7.6; p<0.0001). At 36 months, risk of SCD in patients with indexed LA size26 mm/m2 and NT-proBNP>908 ng/L reached 25% (p<0.0001).. Among HF patients, indexed LA size and NT-proBNP levels are more useful to stratify risk of SCD than other clinical, echocardiographic or biochemical variables. The combination of these two parameters should be considered for predicting SCD in patients with HF.

Topics: Aged; Cardiomegaly; Death, Sudden, Cardiac; Female; Heart Atria; Heart Failure; Humans; Male; Middle Aged; Multivariate Analysis; Natriuretic Peptide, Brain; Peptide Fragments; Predictive Value of Tests; Risk Assessment; Sensitivity and Specificity

Cardiovascular disease is the leading cause of morbidity and mortality in both men and women, but the incidence for women rises sharply after menopause. This has been mainly attributed in the reduction of the female sex hormone estrogen during menopause, suggesting that estrogen may have cardioprotective effects, although how estrogen exerts its cardioprotective effects is not fully understood. Moreover, the beneficial effect of estrogen on end-organ damage such as cardiac hypertrophy (CH) remains unclear. The aim of the present study was to examine the interaction between estrogen and the natriuretic peptide system (NPS) and their possible roles during the development of CH by using the proANP heterozygous atrial natriuretic peptide (ANP +/-) mouse as a model of salt-sensitive CH. Male, female ANP +/- mice, and also ovariectomized (Ovx) female ANP +/- mice treated with oil or estrogen were fed either a normal or high salt (HS) diet. After a 5-week treatment period, marked CH was noted in the male and oil-injected Ovx female ANP +/- mice treated with HS. The cardiac NPS, i.e. ANP, B-type natriuretic peptide, and natriuretic peptide receptor-A, was activated in these ANP +/- mice. Interestingly, the female and estrogen-injected Ovx female ANP +/- mice did not exhibit CH, and the cardiac NPS remained unchanged. Collectively, we provide direct evidence that estrogen has the ability to resist the induction of salt-induced CH in ANP +/- mice. Furthermore, the development of hypertrophy may be activating the cardiac NPS in an attempt to blunt these structural changes.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Estrogens; Female; Guanylate Cyclase; Heterozygote; Male; Mice; Mice, Mutant Strains; Models, Animal; Myocardium; Natriuretic Peptide, Brain; Neprilysin; Receptors, Atrial Natriuretic Factor; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sodium Chloride, Dietary

Better control of cardiovascular function in patients on peritoneal dialysis (PD) is critical because PD patients have a tendency to overhydration, which has been proved to be associated with cardiovascular and patient outcome. In the general population, lipid metabolism is also considered to be an important indicator of future cardiovascular events. Icodextrin has been used to improve ultrafiltration volume without increasing dextrose load. We therefore expected that parameters of lipid metabolism and cardiovascular function could both be improved, or at least maintained, after icodextrin use in PD patients. We therefore analyzed those parameters in 14 prevalent PD patients who required a switch from dextrose to icodextrin solution for the long dwell at 1 year before the switch, at the time of the switch, and at 1 and 2 years after the switch. In the study patients, cardiovascular remodeling evaluated by ultrasonographic left ventricular mass index was diminished, but the intima media area of the cervical artery was elevated after icodextrin use. Intima media thickness did not change over time. Biochemical indices such as brain natriuretic peptide, atrial natriuretic peptide, lipoprotein A, total cholesterol, and triglycerides were all lower after icodextrin use. These results indicate that icodextrin has the potential to improve lipid metabolism, volemic status, and cardiac hypertrophy in prevalent PD patients. However, atherosclerotic vascular change is refractory to improvement.

Topics: Arteries; Atrial Natriuretic Factor; Cardiomegaly; Dialysis Solutions; Glucans; Glucose; Hemodialysis Solutions; Humans; Icodextrin; Lipid Metabolism; Middle Aged; Natriuretic Peptide, Brain; Neck; Peritoneal Dialysis; Tunica Intima; Tunica Media; Ultrasonography; Ventricular Remodeling; Water-Electrolyte Balance

A dihydropyridine calcium (Ca) antagonist, azelnidipine (CAS 123524-52-7, Calblock), exhibits hypotensive effects for a prolonged duration, and has been reported to have a strong antiarteriosclerotic action due to its high affinity for vascular tissues and antioxidative action. It has also been reported that azelnidipine does not cause tachycardia associated with the baroreceptor reflex due to vasodilatation. In this study, the antiarteriosclerotic and cardiac hypertrophy-inhibitory effects, and the autonomic nervous activity in essential hypertension of azelnidipine were investigated. The study was performed using the following 2 protocols: 1) Pulse wave velocity (PWV), carotid arterial intima media thickness (IMT), echocardiography, high sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), adiponectin, brain natriuretic peptide (BNP), and 8-isoprostane were measured after an initial treatment with azelnidipine. 2) The treatment was switched to azelnidipine in patients who had previously been under treatment with amlodipine for essential hypertension, and 123I-metaiodobenzylguanidine myocardial scintigraphy (123I-MIBG), measurements of plasma norepinephrine, atrial natriuretic peptide (ANP), and BNP, Holter electrocardiography, and heart rate variability analysis were performed. PWV, IMT, hs-CRP, IL-6, and TNF-alpha significantly decreased. The levels of 8-isoprostane, an antioxidative marker, were also significantly decreased, while adioponectin levels were significantly increased after the initial treatment with azelnidipine. After switching from amlodipine, azelnidipine exhibited a hypotensive effects comparable to amlodipine, and significantly decreased heart rate and the total number of extrasystoles. Noradrenaline levels and the LF/HF ratio were significantly decreased, and the washout rate was significantly reduced on 123I-MIBG myocardial scintigraphy. These findings suggest that azelnidipine inhibits the enhancement of sympathetic nervous activity and the progression of arteriosclerosis through its antioxidative effects.

Topics: 3-Iodobenzylguanidine; Adipokines; Aged; Antihypertensive Agents; Antioxidants; Arteriosclerosis; Autonomic Nervous System; Azetidinecarboxylic Acid; Calcium Channel Blockers; Cardiomegaly; Carotid Arteries; Catecholamines; Cytokines; Dihydropyridines; Electrocardiography; Female; Heart Rate; Humans; Hypertension; Male; Middle Aged; Natriuretic Peptide, Brain; Pulse; Radionuclide Imaging; Radiopharmaceuticals

Cardiac activator protein-1 (AP-1), composed of c-Jun, is significantly activated by hypertension or angiotensin II (AngII). This study was undertaken to elucidate whether c-Jun could be the potential target for treatment of cardiac hypertrophy. We constructed recombinant adenovirus carrying dominant-negative mutant of c-Jun (Ad.DN-c-Jun). Using catheter-based technique of adenoviral gene transfer, we achieved global myocardial transduction of DN-c-Jun in rats, to specifically inhibit cardiac AP-1. (1) AngII (200 ng/kg/min) infusion in rats caused cardiac hypertrophy, increased cardiac p70S6 kinase activity by 1.3-fold (P<0.05) and enhanced the gene expression of cardiac hypertrophic markers. Ad.DN-c-Jun, which was transferred to the heart 2 days before AngII infusion, prevented cardiac hypertrophy (P<0.01), decreased p70S6 kinase phosphorylation (P<0.05), and suppressed cardiac gene expression of brain natriuretic peptide, collagen I, III, and IV, monocyte chemoattractant protein-1 (MCP-1) and plasminogen activator inhibitor-1 (PAI-1) (P<0.01). (2) In genetically hypertensive rats with cardiac hypertrophy, cardiac gene transfer of Ad.DN-c-Jun, without affecting hypertension, regressed cardiac hypertrophy (P<0.05), and suppressed p70S6 kinase phosphorylation by 20% (P<0.05) and suppressed the enhanced expression of collagen I, III, and IV, MCP-1 and PAI-1. These results provided the first evidence that in vivo blockade of cardiac c-Jun inhibits pathologic cardiac hypertrophy.

Topics: Adenoviridae; Angiotensin II; Animals; Blotting, Western; Cardiomegaly; Chemokine CCL2; Collagen Type I; Collagen Type III; Collagen Type IV; Gene Deletion; Genes, Dominant; Genetic Therapy; Genetic Vectors; Hypertension; Injections; Male; Models, Animal; Natriuretic Peptide, Brain; Phosphorylation; Plasminogen Activator Inhibitor 1; Rats; Rats, Sprague-Dawley; Ribosomal Protein S6 Kinases, 70-kDa; Transcription Factor AP-1

Adrenomedullin (AM) is a multifunctional regulatory peptide, and endogenous AM is an important factor in regulating cardiovascular and renal homeostasis as a potent cardio-reno-protective factor. To illustrate the protective mechanism of adrenomedullin (AM) on the cardiovascular system by observing (1) the changes in mRNA and protein levels of AM and its receptor-calcitonin receptor-like receptor (CL) and receptor activity-modifying proteins (RAMPs)-in myocardia and aortas of spontaneously hypertensive rats (SHRs) and (2) the response of cardiovascular tissue to AM. The AM content and cyclic adenosine monophosphate (cAMP) production in myocardia and aortas were measured in SHRs and Wistar Kyoto (WKY) rats (11-week-old) by radioimmunoassay (RIA). The mRNA levels of brain natriuretic peptide (BNP), AM, CL, RAMP1, -2, -3 were determined by semi-quantitative RTPCR. Protein levels of CL, RAMP1, -2, -3 were assayed by Western blotting. SHRs had severe hypertension, and the tail-blood pressure was 76.7% higher, the ratio of heart weight to body weight (heart coefficient) 45.5% higher, and the BNP gene expression 4.5-fold higher than that of WKY rats (all p < 0.01). The AM-ir content in plasma, myocardia and aortas of SHRs increased by 42.5%, 68.3% and 80.4%, respectively (all p < 0.01) compared with WKY rats. Furthermore, the mRNA levels of AM, CL, RAMP1, RAMP2 and RAMP3 were elevated by 46% (p < 0.01), 62% (p < 0.05), 51.2% (p < 0.01), 41% (p < 0.01) and 54% (p < 0.01), respectively, in myocardia and by 72%, 87%, 155%, 53% and 74% (all p < 0.01), respectively, in aortas. The elevated mRNA level of CL, RAMP1 RAMP2 and RAMP3 correlated positively with that of AM mRNA in hypertrophic myocardia (r= 0.943, 0.621, 0.688 and 0.633, respectively, all p < 0.01) and aortas (r = 0.762, 0.892, 0.828 and 0.736, respectively, all p < 0.01). The protein levels of CL, RAMP1, RAMP2 and RAMP3 in myocardia and aortas of SHRs were increased compared with that of WKY rats. The response to AM was potentiated in myocardia and aortas in SHRs, and the production of cAMP was increased by 47% and 65% (both p < 0.01), respectively. AM-stimulated cAMP generation in myocardia and aortas was blocked by both AM(22-52), the specific antagonist of AM, and calcitonin gene-related peptide (CGRP)(8-37), the antagonist of the CGRP1 receptor. In myocardia and aortas of SHRs, the gene expressions and protein levels of AM, CL, RAMP1, RAMP2 and RAMP3 were increased, and the response to AM was potentiat

Topics: Adrenomedullin; Animals; Aorta; Blood Pressure; Blotting, Western; Calcitonin Receptor-Like Protein; Cardiomegaly; Cyclic AMP; Hypertension; Intracellular Signaling Peptides and Proteins; Male; Membrane Proteins; Myocardium; Natriuretic Peptide, Brain; Radioimmunoassay; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptor Activity-Modifying Protein 1; Receptor Activity-Modifying Protein 2; Receptor Activity-Modifying Protein 3; Receptor Activity-Modifying Proteins; Receptors, Calcitonin; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Up-Regulation

Since exercise training causes cardiac hypertrophy and a single bout induces mechanical stress to the heart, the present study aimed to characterize the activation patterns of multiple MAPK signaling pathways in the heart after a single bout of exercise or chronic exercises. The hearts of untrained rats received 5, 15, and 30 min of treadmill running exercise (Ex5 to Ex30) and rested for 0.5, 1, 3, 6, 12, and 24 h (PostEx0.5 to PostEx24) before subjecting them to the following different experiments. Activation of MAPKs (ERK, JNK, and p38) and MAPKKs (MEK1/2, SEK, and MKK3/6) increased immediately after acute exercise in a time-dependent manner, with ERK, JNK, and p38 peaking at Ex15, Ex15, and Ex30, respectively. Expression of immediate early genes (c-fos, c-jun, and c-myc) was augmented and activator protein-1 DNA binding activity was enhanced in untrained rats immediately after a single bout of exercise. The elevated levels of MAPKs declined to the resting levels within 24 h after exercise. In another set of experiments, following 4, 8, and 12 wk of exercise training, the rats exhibited significant cardiac hypertrophy by week 12. Activation of MAPKs in the 4-wk-trained rats increased after a 30-min single bout of exercise but decreased in the 8-wk group. Finally, the activity of MAPKs signaling in the 12-wk-trained rats exposed to an acute bout of exercise was unaltered. We conclude that exercise induces the activation of multiple MAPK (ERK, JNK, and p38) pathways in the heart, an effect that gradually declines with the development of exercise-induced cardiac hypertrophy.

Topics: Animals; Cardiomegaly; Endothelin-1; Gene Expression Regulation; Heart; Male; Mitogen-Activated Protein Kinases; Myocardium; Natriuretic Peptide, Brain; Physical Conditioning, Animal; Rats; Rats, Sprague-Dawley; RNA, Messenger; Signal Transduction; Time Factors; Transcription Factor AP-1

The cardiovascular benefit of fish oil in humans and experimental animals has been reported. Endothelin (ET)-1 is a well-known cardiac hypertrophic factor. However, although many studies link a fish oil extract, eicosapentaenoic acid (EPA), to cardiac protection, the effects of EPA on cardiac hypertrophy and underlying mechanism(s) are unclear. The present study investigated whether EPA prevents ET-1-induced cardiomyocyte hypertrophy; the potential pathways likely to underlie such an effect were also investigated. Cardiomyocytes were isolated from neonatal rat heart, cultured for 3 days, and then treated for 24 h with vehicle only (control), treated with 0.1 nM ET-1 only, or pretreated with 10 microM EPA and then treated with 0.1 nM ET-1. The cells were harvested, and changes in cell surface area, protein synthesis, expression of a cytoskeletal (alpha-actinin) protein, and cell signaling were analyzed. ET-1 induced a 97% increase in cardiomyocyte surface area, a 72% increase in protein synthesis rate, and an increase in expression of alpha-actinin and signaling molecule [transforming growth factor-beta 1 (TGF-beta 1), c-Jun NH2-terminal kinase (JNK), and c-Jun]. Development of these ET-1-induced cellular changes was attenuated by EPA. Moreover, the hypertrophied cardiomyocytes showed a 1.5- and a 1.7-fold increase in mRNA expression of atrial and brain natriuretic peptides, the classical molecular markers of cardiac hypertrophy, respectively; these changes were also suppressed by EPA. Here we show that ET-1 induces cardiomyocyte hypertrophy and expression of hypertrophic markers, possibly mediated by JNK and TGF-beta 1 signaling pathways. These ET-1-induced effects were blocked by EPA, a major fish oil ingredient, suggesting that fish oil may have beneficial protective effects on cardiac hypertrophy.

Topics: Animals; Animals, Newborn; Atrial Natriuretic Factor; Biomarkers; Blotting, Western; Cardiomegaly; Cell Size; Cells, Cultured; Eicosapentaenoic Acid; Endothelin-1; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique; Immunohistochemistry; JNK Mitogen-Activated Protein Kinases; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phosphorylation; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor beta; Transforming Growth Factor beta1

This study determined whether exercise training prevents pathological hypertrophy in the left ventricle by modulation of myocardial and apoptosis-associated genes. We used spontaneously hypertensive rats (n=15, non-exercise SHR), exercise-trained SHR (n=15, treadmill exercise for 12 weeks), and sedentary Wistar-Kyoto (WKY) rats (n=15). Exercise-trained SHR expressed adaptive changes such as reduced body weight, heart rate, blood pressures, left ventricle wall thickness, lipid profiles, and homocysteine level. The mRNA expression of angiotensin converting enzyme, endothelin-1, and brain natriuretic peptides in the heart was lower in the exercise-trained SHR and in the WKY than in the non-exercise SHR, whereas mRNA expression of caveolin-3 and eNOS in the heart was higher. Bcl-2 protein was higher in the exercise-trained SHR than in the WKY and the non-exercise SHR. In contrast, Bax protein levels were lower in the exercise-trained SHR and in the WKY than in the non-exercise SHR. Furthermore, the levels of the active forms of caspase-3 (20 kDa) were lower in the exercise-trained SHR and in the WKY than in the non-exercise SHR. These findings suggest that exercise training prevents pathological hypertrophy in the left ventricle by modulation of myocardial genes and that it interferes with a signal transduction pathway of apoptosis secondary to the pathological cardiac hypertrophy.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Blood Pressure; Body Weight; Cardiomegaly; Caspase 3; Caspases; Caveolin 3; Endothelin-1; Gene Expression; Heart Rate; Homocysteine; Lipids; Male; Myosin Heavy Chains; Natriuretic Peptide, Brain; Nitric Oxide Synthase Type III; Peptidyl-Dipeptidase A; Physical Conditioning, Animal; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Inbred SHR; Rats, Inbred WKY; RNA, Messenger

The activation of the calcineurin-nuclear factor of activated T cells cascade during the development of pressure-overload cardiac hypertrophy has been previously reported in a number of studies. In addition, numerous pharmacological studies involving calcineurin inhibitors such as FK506 and cyclosporine A have now demonstrated that these agents can prevent such hypertrophic responses in the heart. However, little is known regarding the roles of the calcineurin downstream effector--nuclear factor of activated T cells. Our present study has further examined the roles of nuclear factor of activated T cells in pressure-overload cardiac hypertrophy by employing a recently developed cell-permeable nuclear factor of activated T cells inhibitor peptide. Rat hearts were subjected to pressure overload attributable by 4 weeks of aortic banding, and then treated with this cell-permeable nuclear factor of activated T cells inhibitor peptide and a control peptide. Treatment with the inhibitor was found to significantly decrease the heart weight/body weight ratio, the size of cardiac myocytes, and the serum brain natriuretic peptide and atrial natriuretic peptide levels. These results suggest that nuclear factor of activated T cells functions in a key role in the development of cardiac hypertrophy during pressure overload. Inhibition of nuclear factor of activated T cells by a specific inhibitor peptide is a suitable method for characterization of the molecular mechanisms underlying cardiac hypertrophy as well as in the search for new promising therapies for disease.

Topics: Animals; Aorta, Abdominal; Atrial Natriuretic Factor; Calcineurin; Cardiomegaly; Cell Membrane Permeability; Male; Natriuretic Peptide, Brain; NFATC Transcription Factors; Oligopeptides; Rats; Rats, Wistar; Signal Transduction; Ventricular Pressure

We evaluated relationships among two circulating molecular forms of brain natriuretic peptide (BNP32 and NT-proBNP), severity of hypertension (HTN), and cardiac hypertrophy in subjects with mild, moderate, and severe HTN. We prospectively studied 78 patients (43 males; mean age 51.4 +/- 11 yr) with essential HTN and 28 age- and sex-matched controls. BNP32 and NT-proBNP were measured by radioimmunoassay. In grade 1 HTN, BNP32 was not elevated and NT-proBNP was reduced (P = 0.030) compared with controls. However, log-transformed values of BNP32 and NT-proBNP were both increased with severity of HTN from grade 1 to 3 (P <0.0001 and P = 0.003, respectively). By multivariate analysis, log BNP32 was independently predicted by age (beta = 0.210, P = 0.026) and HTN grade (beta = 0.274, P = 0.004), whereas log NT-proBNP was independently predicted by sex (beta = 0.235, P = 0.012) and HTN grade (beta = 0.218, P = 0.0023). Two forms of BNP were measured in normal subjects and patients with essential HTN. In grade 1 HTN, BNP32 was unchanged and NT-proBNP was significantly reduced compared with controls. As severity increased in humans with grade 1 to 3 HTN, both BNP32 and NT-proBNP levels were increased while not being affected by the presence of left ventricular hypertrophy. The lack of activation of BNP32 together with the reduction of NT-proBNP in grade 1 HTN may represent an impaired response of the BNP system in the early phase of HTN. The later activation of both forms of BNP may be a late compensatory effect, because it correlates with severity of HTN rather than cardiac hypertrophy/remodeling.

Topics: Blood Pressure; Cardiomegaly; Echocardiography; Female; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Middle Aged; Multivariate Analysis; Natriuretic Peptide, Brain; Peptide Fragments; Prospective Studies; Severity of Illness Index; Ventricular Remodeling

Because apelin may play an important regulatory role in human cardiac dysfunction, we investigated alterations in cardiovascular content of apelin and its receptor, APJ, during hypertension and the effect of exercise training on the cardiovascular apelin/APJ system in hypertensive animals. Spontaneously hypertensive rats (SHRs) underwent swimming training consisting of 54 swimming sessions of 60 min each (6 days/week for 9 weeks). Systolic blood pressure (SBP) was verified weekly by tail-cuff plethysmography. Apelin levels in plasma and cardiovascular tissues were determined by radioimmunoassay. The level of apelin/APJ mRNA was determined by RT-PCR. SHRs showed severe hypertension and pathological cardiomegaly. The level of apelin immunoreactivity (apelin-ir) in plasma and ventricular and aortic tissues was lower, by 40%, 40% and 42% (all P<0.01), respectively, in SHRs than in control Wistar-Kyoto rats, and the mRNA level of apelin and APJ in myocardium and aorta was markedly decreased. Compared with sedentary SHRs, swimming-trained SHRs showed decreased SBP and elevated mRNA expression of apelin and APJ in cardiovascular tissues and elevated apelin-ir level in plasma, myocardium and aorta (all P<0.01). SBP and level of apelin-ir in plasma and cardiovascular tissues were negatively correlated. Long-term swimming training relieved the pathogenesis of hypertension and reversed the downregulation of the cardiovascular apelin/APJ system induced by hypertension, which suggests that the improving effect of exercise training on hypertension could be mediated by upregulating the cardiovascular apelin/APJ system.

Topics: Animals; Aorta; Apelin; Apelin Receptors; Blood Pressure; Cardiomegaly; Cardiovascular System; Carrier Proteins; Intercellular Signaling Peptides and Proteins; Male; Myocardium; Natriuretic Peptide, Brain; Physical Conditioning, Animal; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptors, G-Protein-Coupled; Reverse Transcriptase Polymerase Chain Reaction; Swimming; Up-Regulation

The inhibition of glycogen synthase kinase-3beta (GSK-3beta) via phosphorylation by Akt or protein kinase C (PKC), or the activation of mitogen-activated protein kinase (MAPK) cascades can play a pivotal role in left ventricular remodeling following myocardial infarction. Our previous data showed that MAPK and phosphatidylinositol-3-kinase/Akt pathways could be modulated by poly(ADP-ribose)polymerase (PARP) inhibition raising the possibility that cardiac hypertrophic signaling responses may be favorably influenced by PARP inhibitors. A novel PARP inhibitor (L-2286) was tested in a rat model of chronic heart failure following isoproterenol-induced myocardial infarction. Subsequently, cardiac hypertrophy and interstitial collagen deposition were assessed; additionally, mitochondrial enzyme activity and the phosphorylation state of GSK-3beta, Akt, PKC and MAPK cascades were monitored. PARP inhibitor (L-2286) treatment significantly reduced the progression of postinfarction heart failure attenuating cardiac hypertrophy and interstitial fibrosis, and preserving the integrity of respiratory complexes. More importantly, L-2286 repressed the hypertrophy-associated increased phosphorylation of panPKC, PKC alpha/betaII, PKC delta and PKC epsilon, which could be responsible for the activation of the antihypertrophic GSK-3beta. This work provides the first evidence that PARP inhibition beneficially modulates the PKC/GSK-3beta intracellular signaling pathway in a rat model of chronic heart failure identifying a novel drug target to treat heart failure.

Topics: Animals; Cardiomegaly; Collagen Type III; Electrocardiography; Enzyme Inhibitors; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Heart Failure; Isoproterenol; Male; Mitogen-Activated Protein Kinases; Myocardial Infarction; Natriuretic Peptide, Brain; Phosphorylation; Piperidines; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Protein Kinase C; Quinazolines; Rats; Rats, Sprague-Dawley; Signal Transduction; Ventricular Remodeling

Brain natriuretic peptide (BNP) affects the regulation of myocardial metabolism through the production of cGMP and these effects may be altered by cardiac hypertrophy. We tested the hypothesis that BNP would cause decreased metabolism and function in the heart and cardiac myocytes by increasing cGMP and that these effects would be disrupted after thyroxine-induced cardiac hypertrophy (T4). Open-chest control and T4 rabbits were instrumented to determine local effects of epicardial BNP (10(-3) M). Function of isolated cardiac myocytes was examined with BNP (10(-8)-10(-7) M) with or without KT5823 (10(-6) M, cGMP protein kinase inhibitor). Cyclic GMP levels were measured in myocytes. In open-chest controls, O2 consumption was reduced in the BNP area of the subepicardium (6.6+/-1.3 ml O2/min/100 g versus 8.9+/-1.4 ml O2/min/100 g) and subendocardium (9.4+/-1.3 versus 11.3+/-0.99). In T4 animals, functional and metabolic rates were higher than controls, but there was no difference between BNP-treated and untreated areas. In isolated control myocytes, BNP (10(-7) M) reduced percent shortening (PSH) from 6.5+/-0.6 to 4.3+/-0.4%. With KT5823 there was no effect of BNP on PSH. In T4 myocytes, BNP had no effect on PSH. In control myocytes, BNP caused cGMP levels to rise from 279+/-8 to 584+/-14 fmol/10(5) cells. In T4 myocytes, baseline cGMP levels were lower (117+/-2 l) and were not significantly increased by BNP. Thus, BNP caused decreased metabolism and function while increasing cGMP in control. These effects were lost after T4 due to lack of cGMP production. These data indicated that the effects of BNP on heart function operated through a cGMP-dependent mechanism, and that this mechanism was disrupted in T4-induced cardiac hypertrophy.

Topics: Animals; Cardiomegaly; Cyclic GMP; Myocardium; Natriuretic Peptide, Brain; Oxygen Consumption; Rabbits; Thyroxine

The role of the angiotensin II type 2 receptor (AT2) during alterations in cardiac size remains largely unclear. Through employment of an AT2 antagonist, the present study explored a possible involvement of the AT2 receptor during salt-induced cardiac hypertrophy in the proatrial natriuretic peptide gene-disrupted mouse (ANP-/-). ANP-/- mice received either saline solution or the AT2 antagonist, PD123319, and were then placed on a high salt diet (8.0% NaCl) for 3 weeks. Cardiac and pulmonary size, expression of the renin-angiotensin system (RAS), and the behaviour of various hypertrophy marker genes were assessed. PD123319 caused enhanced expression of the systemic RAS, yet the cardiac RAS was largely unaffected. Although AT2 blockade did not alter whole cardiac mass, right ventricle mass, as well as pulmonary mass-to-body mass ratios were significantly decreased. Collagen type I was decreased in the latter tissues, likely contributing to the regression in mass. Several players essential in the maintenance of myocardial extracellular matrix homeostasis including B-type natriuretic peptide, matrix metalloproteinase-2, tumour necrosis factor, and transforming growth factor were also significantly altered by PD123319. These data suggest that AT2 blockade is involved in significant changes in myocardial extracellular matrix components translating into decreases in tissue mass in the salt-sensitive ANP-/- animal.

Topics: Angiotensin II Type 2 Receptor Blockers; Animals; Atrial Natriuretic Factor; Cardiomegaly; Collagen Type I; Heart; Imidazoles; Kidney; Lung; Matrix Metalloproteinase 2; Mice; Mice, Transgenic; Mutation, Missense; Natriuretic Peptide, Brain; Organ Size; Peptidyl-Dipeptidase A; Pyridines; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Receptors, Atrial Natriuretic Factor; Renin-Angiotensin System; RNA, Messenger; Sodium Chloride, Dietary; Transforming Growth Factor beta1; Tumor Necrosis Factor-alpha; Vasoconstrictor Agents

High levels of microphthalmia transcription factor (MITF) expression have been described in several cell types, including melanocytes, mast cells, and osteoclasts. MITF plays a pivotal role in the regulation of specific genes in these cells. Although its mRNA has been found to be present in relatively high levels in the heart, its cardiac role has never been explored. Here we show that a specific heart isoform of MITF is expressed in cardiomyocytes and can be induced by beta-adrenergic stimulation but not by paired box gene 3 (PAX3), the regulator of the melanocyte MITF isoform. In 2 mouse strains with different MITF mutations, heart weight/body weight ratio was decreased as was the hypertrophic response to beta-adrenergic stimulation. These mice also demonstrated a tendency to sudden death following beta-adrenergic stimulation. Most impressively, 15-month-old MITF-mutated mice had greatly decreased heart weight/body weight ratio, systolic function, and cardiac output. In contrast with normal mice, in the MITF-mutated mice, beta-adrenergic stimulation failed to induce B-type natriuretic peptide (BNP), an important modulator of cardiac hypertrophy, while atrial natriuretic peptide levels and phosphorylated Akt were increased, suggesting a cardiac stress response. In addition, cardiomyocytes cultured with siRNA against MITF showed a substantial decrease in BNP promoter activity. Thus, for what we believe is the first time, we have demonstrated that MITF plays an essential role in beta-adrenergic-induced cardiac hypertrophy.

Topics: Animals; Body Weight; Cardiomegaly; Cell Enlargement; Cell Line; Extracellular Signal-Regulated MAP Kinases; Gene Expression; Heart; Isoproterenol; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Mutant Strains; Microphthalmia-Associated Transcription Factor; Models, Biological; Mutation; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; NIH 3T3 Cells; Organ Size; Paired Box Transcription Factors; PAX3 Transcription Factor; Phosphorylation; Proto-Oncogene Proteins c-akt; RNA, Small Interfering

Cardiovascular complications proportionally increase as chronic kidney diseases (CKD) progress into chronic renal insufficiency or failure. The present study addressed whether the long-term use of angiotensin II receptor blocker (ARB) exerts a cardio-protective effect in CKD patients with mild to moderate renal damage.. Fifteen patients with CKD above stage 3 were enrolled in the study. While their previous antihypertensive therapy remained unchanged, the ARB candesartan, was newly added to the concurrent therapy and the patients were followed for 12-24 months thereafter.. The main results were as follows: 1) The use of ARB improved the status of BP control classifications, shifting them to the better control categories where there was less morning hypertension. 2) ARB significantly reduced the left ventricular (LV) mass index(LVMI), the relative wall thickness (RWT), the LV intra-dimension in diastole(LVIDd), and as a result, the LV ejection fraction(LVEF) improved. In parallel, the LV mass category shifted to lower categories, indicating a significant improvement. 3) The levels of BNP decreased significantly from 135.2 +/- 136.0 to 85.0 +/- 80.3 pg/mL. 4) ARB reduced urinary protein excretion in all cases. Regardless of an inevitable increase in the serum creatinine(Cr) concentration, the slope of reciprocal serum Cr concentration (l/Cr) in the treatment period with ARB was significantly less steep compared to that in the run-in period. 5) Throughout the observation period, no serious side effects were found in any of the patients.. The present study indicated that the long-term use of ARB exerts both cardio-, and renoprotective effects in patients with advanced CKD. This agent could be especially indicative and useful not only for patients with CKD, but also for patients of CKD with cardiac hypertrophy.

Topics: Aged; Angiotensin II Type 1 Receptor Blockers; Cardiomegaly; Chronic Disease; Female; Humans; Kidney Diseases; Male; Natriuretic Peptide, Brain

Pioglitazone, one of the synthetic peroxisome proliferator-activated receptor (PPARgamma) agonists, has been found to inhibit inflammatory response. However, it is not known yet whether the preventive effect of pioglitazone on cardiac hypertrophy is related to its antiinflammatory function. The objective of this study was to investigate the role of pioglitazone in attenuation of cardiac hypertrophy and its relation to the inhibitory effect on the inflammatory cytokine expression in cultured neonatal rat cardiomyocytes. The mRNA expression of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), interleukin (IL)-1beta, IL-6, and PPARgamma was measured by using RT-PCR. Cardiomyocyte hypertrophy was induced by stimulating angiotensin II (Ang II) and evaluated both by measuring surface area of cardiac myocyte and 3H-leucine incorporation. The expressions of IL-1beta, IL-6, ANP, and BNP were significantly enhanced, whereas that of PPARgamma was significantly reduced in Ang II-induced hypertrophic cardiomyocytes. Pioglitazone decreased cardiac myocyte surface area and inhibited 3H-leucine incorporation into cardiomyocytes. Furthermore, pioglitazone upregulated the suppressed expression of PPARgamma and attenuated the increased IL-1beta and IL-6 expression. The effect of pioglitazone might be associated with PPARgamma activation and the consequent antiinflammatory function in prevention and treatment of cardiac hypertrophy.

Topics: Angiotensin II; Animals; Anti-Inflammatory Agents; Atrial Natriuretic Factor; Cardiomegaly; Cells, Cultured; Interleukin-1beta; Interleukin-6; Leucine; Myocytes, Cardiac; Natriuretic Peptide, Brain; Pioglitazone; PPAR gamma; Rats; Rats, Wistar; RNA, Messenger; Thiazolidinediones

To investigate the effects of pioglitazone on cardiac hypertrophy in vitro and in vivo.. Angiotensin II was used to establish hypertrophy of cardiac myocytes and pioglitazone was applied to these myocytes in various dosages in vitro. ANP and BNP mRNA expression was evaluated by RT-PCR, and the rate of protein synthesis in CM by 3H-leucine incorporation in cardiac myocytes. Left ventricular hypertrophy was induced by incomplete ligation of abdominal aorta of rats and pioglitazone (20 mg x kg(-1). day(-1)) was administrated one week prior to the operation until 4 weeks after the operation. Cytokines mRNA expression in left ventricle was measured by RT-PCR, left ventricular wall thickness and myocyte diameter were determined by pathological method.. Pioglitazone inhibited ANP and BNP mRNA expression and 3H-leucine incorporation in neonatal rat cardiac myocytes induced by angiotensin II in a dose-dependent manner in vitro. Furthermore, pioglitazone reduced the mRNA expression of proinflammatory cytokines, including interleukin-1 beta and cardiotrophin-1, and inhibited the pressure overload-induced increase in the ratio of heart weight to body weight, left ventricular wall thickness and myocyte diameter of rats in vivo.. Pioglitazone inhibits cardiac hypertrophy of rats in vitro and in vivo, and may play a role in prevention and treatment of cardiovascular diseases characterized by cardiac hypertrophy in future.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Cell Line; Cytokines; Disease Models, Animal; Interleukin-1beta; Male; Myocytes, Cardiac; Natriuretic Peptide, Brain; Pioglitazone; Rats; Rats, Sprague-Dawley; RNA, Messenger; Thiazolidinediones

Cardiac hypertrophy is a complex and nonhomogenous response to various stimuli. In this study, we used high-density oligonucleotide microarray to examine gene expression profiles during physiological hypertrophy, pathological hypertrophy, and heart failure in Dahl salt-sensitive rats. There were changes in 404/3,160 and 874/3,160 genes between physiological and pathological hypertrophy and the transition from hypertrophy to heart failure, respectively. There were increases in stress response genes (e.g., heat shock proteins) and inflammation-related genes (e.g., pancreatitis-associated protein and arachidonate 12-lipoxygenase) in pathological processes but not in physiological hypertrophy. Furthermore, atrial natriuretic factor and brain natriuretic protein showed distinctive changes that are very specific to different conditions. In addition, we used a resampling-based gene score-calculating method to define significantly altered gene clusters, based on Gene Ontology classification. It revealed significant alterations in genes involved in the apoptosis pathway during pathological hypertrophy, suggesting that the apoptosis pathway may play a role during the transition to heart failure. In addition, there were significant changes in glucose/insulin signaling, protein biosynthesis, and epidermal growth factor signaling during physiological hypertrophy but not during pathological hypertrophy.

Topics: Animals; Apoptosis; Atrial Natriuretic Factor; Blotting, Northern; Cardiomegaly; Echocardiography; Epidermal Growth Factor; Gene Expression Profiling; Gene Expression Regulation; Heart Failure; Hypertrophy; Inflammation; Insulin; Natriuretic Peptide, Brain; Oligonucleotide Array Sequence Analysis; Pancreatitis-Associated Proteins; Physical Conditioning, Animal; Rats; Rats, Inbred Dahl; RNA; Signal Transduction

Cyclic guanosine monophosphate (cGMP), which is implicated in cardiac cell growth and function, is synthesized by cytoplasmic soluble guanylyl cyclase (GC) stimulated via nitric oxide (NO) and by particulate membrane-bound GC activated via natriuretic peptides. We investigated possible cGMP elevation in the left ventricle (LV) of rats developing physiologic LV hypertrophy during gestation. Furthermore, expression of estrogen receptors (ER) and oxytocin receptors (OTR) was evaluated because their activation stimulates NO and atrial natriuretic peptide (ANP) release from the heart. Compared with nonpregnant controls, Sprague-Dawley rats on day 7 of gestation had similar heart weights, but, on days 14 and 21, ventricular mass increased by 12% and 28% respectively (P< 0.05). LV cGMP concentration was elevated at day 14 of gestation (3.25 +/- 0.12 vs 4.65 +/- 0.17 pmol/g wet weight, P< 0.01) but decreased at day 21 (2.45 +/- 0.09 pmol/g, P< 0.05) to increase again on postpartum day 1 (6.01 +/- 0.15 pmol/g) and day 4 (9.21 +/- 1.79 pmol/g). Changes in endothelial nitric oxide synthase (eNOS), inducible NOS (iNOS), OTR and ERalpha, but not ERbeta, proteins paralleled the pregnancy-related cGMP changes in the LV. In contrast, ANP mRNA of the LV remained at control level throughout gestation but increased postpartum, whereas brain natriuretic peptide (BNP) expression declined at term and increased postpartum. The particulate GC natriuretic peptide receptors (GC-A and GC-B) transcripts were already lower at day 14 of gestation. Natriuretic peptide clearance receptor (NPR-C) transcript was not altered on days 7 and 14, but increased at term. We conclude that cGMP concentration in the rat LV is influenced by both NOS and natriuretic peptide systems and may be involved in the changes of LV contractility and hypertrophy that occur during rat gestation.

Topics: Animals; Atrial Natriuretic Factor; Blotting, Northern; Blotting, Western; Cardiomegaly; Cyclic GMP; Estrogen Receptor alpha; Estrogen Receptor beta; Female; Heart Ventricles; Immunohistochemistry; Myocardium; Natriuretic Peptide, Brain; Natriuretic Peptides; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Pregnancy; Rats; Receptors, Oxytocin; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

The effects of long-acting calcium channel blockers (CCBs) on pressure overload-induced cardiac remodeling are seldom studied in animals. We evaluated the effects of benidipine, a long-acting CCB, on cardiac remodeling.. Rat neonatal cardiac myocytes were used to examine the influence of benidipine on protein synthesis. Cardiac remodeling was induced in C57 B6/J mice by transverse aortic constriction (TAC). Then the effects of benidipine (10 mg/kg/d) were assessed on myocardial hypertrophy and heart failure, cardiac histology, and gene expression.. Benidipine significantly inhibited protein synthesis by cardiac myocytes stimulated with phenylephrine (PE), and this effect was partially abolished by cotreatment with a nitric oxide synthase (NOS) inhibitor [N(G)-nitro-l-arginine methylester (l-NAME)]. Four weeks after the onset of pressure overload, benidipine therapy potently inhibited cardiac hypertrophy and prevented heart failure. The heart to body weight ratio was 6.89+/-0.48 mg/g in treated mice vs. 8.76+/-0.33 mg/g in untreated mice (P<0.01), and the lung to body weight ratio was 7.39+/-0.93 mg/g vs. 10.53+/-0.99 mg/g, respectively (P<0.05). Left ventricular fractional shortening (LVFS) was improved on echocardiography. Plasma NO levels were increased, while B type natriuretic peptide, protein inhibitor of neuronal NOS, and procollagen IV alpha were down-regulated in benidipine-treated mice.. These results indicate that benidipine inhibits cardiac remodeling due to pressure overload at least partly by acting on the nitric oxide signaling pathway.

Topics: Animals; Biomarkers; Calcium Channel Blockers; Cardiomegaly; Cells, Cultured; Collagen Type IV; Dihydropyridines; Disease Progression; Gene Expression Regulation; Heart Failure; Male; Mice; Mice, Inbred C57BL; Muscle Proteins; Myocytes, Cardiac; Natriuretic Peptide, Brain; Nitric Oxide; Signal Transduction; Ventricular Remodeling

The extent of left ventricular (LV) diastolic dysfunction is related to the finding that some patients with cardiomegaly due to LV systolic dysfunction have good exercise tolerance, although others have limited tolerance. A brain-type natriuretic peptide level of >/=104 pg/ml reliably enables the detection of relatively worse LV diastolic function in patients with systolic dysfunction, and this value may provide clinically useful information for the management of patients with cardiomegaly.

Topics: Biomarkers; Cardiomegaly; Female; Humans; Male; Middle Aged; Natriuretic Peptide, Brain; Systole; Ventricular Dysfunction, Left

Although disruption of guanylyl cyclase (GC) A, a natriuretic peptide receptor, induces cardiac hypertrophy and fibrosis, the molecular mechanism underlying these effects are not well understood. In this study, we examined the role of calcineurin, a calcium-dependent phosphatase, in cardiac remodeling in GCA-knockout (GCA-KO) mice.. At 14 weeks of age, calcineurin activity, nuclear translocation of nuclear factor of activated T cells c3 (NFATc3), and modulatory calcineurin-interacting protein 1 (MCIP1) gene expressions were increased in the hearts of GCA-KO mice compared with wild-type (WT) mice. Blockade of calcineurin activation by FK506 (6 mg/kg body weight administered subcutaneously once a day from 10 to 14 weeks of age) significantly decreased the heart-to-body weight ratio, cardiomyocyte size, and collagen volume fraction in GCA-KO mice, whereas FK506 did not affect these parameters in WT mice. Overexpression of atrial and brain natriuretic peptides, collagen, and fibronectin mRNAs in GCA-KO mice was also attenuated by FK506. Electrophoretic mobility shift assays demonstrated that GATA4 DNA-binding activity was increased in GCA-KO mice, and this increase was inhibited by calcineurin blockade. In neonatal cultured cardiac myocytes, inhibition of GCA by HS142-1 (100 microg/mL) increased basal and phenylephrine (10(-6) mol/L)-stimulated calcineurin activity, nuclear translocation of NFATc3, and MCIP1 mRNA expression. In contrast, activation of GCA by atrial natriuretic peptide (10(-6) mol/L) inhibited phenylephrine (10(-6) mol/L)-stimulated nuclear translocation of NFATc3.. These results suggest that activation of cardiac GCA by locally secreted natriuretic peptides protects the heart from excessive cardiac remodeling by inhibiting the calcineurin-NFAT pathway.

Topics: Animals; Atrial Natriuretic Factor; Calcineurin; Calcineurin Inhibitors; Cardiomegaly; DNA-Binding Proteins; Enzyme Activation; Fibrosis; Gene Expression Regulation; Guanylate Cyclase; Intracellular Signaling Peptides and Proteins; Mice; Mice, Knockout; Muscle Proteins; Myocardium; Natriuretic Peptide, Brain; NFATC Transcription Factors; Receptors, Atrial Natriuretic Factor; RNA, Messenger; Tacrolimus

Serum response factor (SRF) is a transcription factor required for the regulation of genes important for cardiac structure and function. Notably, the "fetal gene expression profile" that is characteristic of cardiac hypertrophy consists of genes known to be regulated by SRF. Transgenic animal studies suggest that cardiac-specific overexpression of SRF induces this pattern of hypertrophic genes and subsequently causes the progression of pathologic adaptations. Furthermore, studies examining cardiac tissues from patients with severe heart failure indicate significant alterations in SRF expression that correspond with alterations in expression of SRF-dependent genes. Based on these observations, it has been postulated that SRF may be critical for stimulating pathologic gene expression at the onset of hypertrophic adaptation. To address the role of SRF in cardiac hypertrophy we investigated whether SRF is necessary and sufficient for the expression of genes associated with the hypertrophic response. We used isolated cardiomyocytes from both neonatal rats, and transgenic mice containing floxed SRF alleles, to examine cardiac gene expression in response to overexpression and absence of SRF. Using this approach, we demonstrate that SRF is required for the induction of atrial naturetic factor (ANF), c-fos, NCX1, BNP, alpha-actins, alpha-myosin heavy chain, and beta-myosin heavy chain genes. However, overexpression of exogenous SRF in isolated cardiomyocytes is only sufficient to induce NCX1 and alpha-myosin heavy chain. These results indicate that SRF is critical for the regulation and induction of genes associated with the progression of pathologic cardiac hypertrophy, however, the pattern of genes induced by overexpression of SRF in isolated cardiomyocytes is different from those genes expressed in hypertrophic transgenic hearts. This suggests that SRF-dependent gene expression is modulated in a complex manner by in vivo physiologic systems prior to and during heart failure as the organism adapts to cardiac stress.

Topics: Actins; Adenoviridae; Animals; Animals, Newborn; Atrial Natriuretic Factor; Cardiomegaly; Cells, Cultured; Fluorescent Antibody Technique, Indirect; Gene Expression Regulation, Developmental; Genes, Reporter; Green Fluorescent Proteins; Heart Ventricles; Luciferases; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Proto-Oncogene Proteins c-fos; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; Serum Response Factor; Sodium-Calcium Exchanger

To confirm that alpha1, beta adrenoceptor antagonists and angiotensin II type 1 receptor blockers (ARBs) have different abilities to attenuate progressive cardiac hypertrophy despite their comparable lowering of blood pressure, we compared the effect of these agents alone or in combination on hypertensive cardiac hypertrophy. Eight-week-old spontaneously hypertensive rats (SHR) were divided into 7 groups. Single administration of doxazosin, atenolol, or losartan, or half-dose combinations of these drugs were given orally for 6 weeks. The control group did not receive any drugs. The heart weight-to-body weight ratio (HW/BW), left ventricular mass index (LVMI), plasma brain natriuretic peptide (BNP) and left ventricular BNP mRNA expression were measured after 6-week administration. Blood pressure did not differ among the drug-treated groups, all of which showed lower blood pressure than the control group. The HW/BW and LVMI of the drug-treated groups, except the doxazosin group, were lower than in the control group. Moreover, the LVMI values of the groups receiving losartan were significantly lower than those in the groups without losartan (p < 0.05). Plasma BNP of the drug-treated groups was lower than that in the control group (p < 0.05). The left ventricular BNP mRNA expression of the drug-treated groups, except the doxazosin group, was lower than that in the control group. The atenolol group showed a higher level of BNP mRNA than the groups receiving losartan monotherapy or combination therapies (p < 0.05). In conclusion, the ARB had the strongest attenuating effect on the development of hypertensive cardiac hypertrophy, and the alpha1 and beta adrenergic receptor blockers were more effective in combination than as monotherapies in SHR.

Topics: Adrenergic alpha-Antagonists; Adrenergic beta-Antagonists; Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Animals; Atenolol; Blood Pressure; Cardiomegaly; Doxazosin; Drug Therapy, Combination; Echocardiography; Heart Rate; Hypertension; Losartan; Male; Natriuretic Peptide, Brain; Rats; Rats, Inbred SHR; RNA, Messenger

Several reports have suggested that the TAK1-MKK3/6-p38MAPK signaling axis is important for TGF-beta-related cardiac hypertrophy. Despite this, the effects of exogenous TGF-beta on cardiac hypertrophy and associated signaling mechanisms have not been demonstrated directly. Moreover, the roles of the signaling mechanisms involved in cardiac hypertrophy (TAK1 upstream and p38MAPK downstream) remain unclear. In this study, we investigated the potential involvement of protein kinase C and activating transcription factor-2 in TGF-beta1-induced cardiac hypertrophic responses in cultured neonatal rat ventricular cardiomyocytes. TGF-beta1 treatment resulted in upregulation of mRNA expression or promoter activities of beta-myosin heavy chain, atrial natriuretic factor, and brain natriuretic peptide, and increased myocyte protein content, cell size, and sarcomeric organization. These are all characteristic hallmarks of cardiac hypertrophy. PKC was found to be involved throughout the signaling system, and it was shown that it acts by mediating upstream TAK1 activation and leads to ATF-2 activation. PKC-dependent ATF-2 activation was shown to be involved in TGF-beta1-induced cardiac hypertrophic responses. The PKC inhibitors, GO6976 and GF109203X, completely blocked TGF-beta1-induced TAK1 kinase activity and subsequent downstream signaling pathways including ATF-2 phosphorylation, leading to suppression of ATF-2 transcriptional activity. This inhibitory effect was reflected in cardiac hypertrophic responses such as inhibitions of beta-MHC gene induction and ANF promoter activity. Our results suggest that PKC is involved in TGF-beta1-induced cardiac hypertrophic responses in our cell culture system and that ATF-2 activation plays a role.

Topics: Activating Transcription Factor 2; Animals; Atrial Natriuretic Factor; Carbazoles; Cardiomegaly; Cyclic AMP Response Element-Binding Protein; Gene Expression; Gene Expression Regulation; Indoles; Maleimides; MAP Kinase Kinase Kinases; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; Promoter Regions, Genetic; Protein Kinase C; Rats; RNA, Messenger; Transcription Factors; Transcriptional Activation; Transforming Growth Factor beta; Transforming Growth Factor beta1

In this study we examined diabetes- and hypertension-induced changes in cardiac structure and function in an animal model of type 2 diabetes, the Goto-Kakizaki (GK) rat. We hypothesized that treatment with omapatrilat, a vasopeptidase inhibitor, which causes simultaneous inhibition of angiotensin converting enzyme and neutral endopeptidase, provides additional cardioprotective effects, during normal- as well as high sodium intake, compared to treatment with enalapril, a selective inhibitor of angiotensin converting enzyme. Fifty-two GK rats were randomized into 6 groups to receive either normal-sodium (NaCl 0.8%) or high-sodium (NaCl 6%) diet and enalapril, omapatrilat or vehicle for 12 weeks. The GK rats developed hypertension, cardiac hypertrophy and overexpression of cardiac natriuretic peptides and profibrotic connective tissue growth factor compared to nondiabetic Wistar rats. The high dietary sodium further increased the systolic blood pressure, and changed the mitral inflow pattern measured by echocardiography towards diastolic dysfunction. Enalapril and omapatrilat equally decreased the systolic blood pressure compared to the control group during normal- as well as high-sodium diet. Both drugs had beneficial cardioprotective effects, which were blunted by the high dietary sodium. Compared to enalapril, omapatrilat reduced the echocardiographically measured left ventricular mass during normal-sodium diet and improved the diastolic function during high-sodium diet in GK rats. Furthermore, omapatrilat reduced relative cardiac weight more effectively than enalapril during high sodium intake. Our results suggest that both the renin-angiotensin and the neutral endopeptidase system are involved in the pathogenesis of diabetic cardiomyopathy since vasopeptidase inhibition was shown to provide additional benefits in comparison with selective angiotensin converting enzyme inhibition alone.

Topics: Aldosterone; Angiotensin-Converting Enzyme Inhibitors; Animals; Atrial Natriuretic Factor; Blood Glucose; Blood Pressure; Body Weight; Cardiomegaly; Collagen; Diabetes Mellitus, Type 2; Echocardiography; Enalapril; Fibrosis; Heart; Insulin; Male; Metalloendopeptidases; Myocardium; Natriuretic Peptide, Brain; Organ Size; Protease Inhibitors; Pyridines; Random Allocation; Rats; Rats, Wistar; RNA, Messenger; Sodium Chloride, Dietary; Thiazepines

The epidermal growth factor receptor (EGFR) and ectoshedding of heparin-binding epidermal growth factor (HBEGF), an EGFR ligand, have been linked to the development of cardiac myocyte hypertrophy. However, the precise role that the liganded EGFR plays in the transcriptional activation of the gene program that accompanies hypertrophy remains undefined. Utilizing the human (h) BNP gene as a model of hypertrophy-dependent gene activation, we show that activation of the EGFR plays an important role in mediating mechanical strain-dependent stimulation of the hBNP promoter. Strain promotes endothelin (ET) generation through NAD(P)H oxidase-dependent production of reactive oxygen species. ET in turn induces metalloproteinase-mediated cleavage of pro-HBEGF and ectoshedding of HBEGF, which activates the EGFR and stimulates hBNP promoter activity. HBEGF also stimulates other phenotypic markers of hypertrophy including protein synthesis and sarcomeric assembly. The antioxidant N-acetylcysteine or the NAD(P)H oxidase inhibitor, apocynin, inhibited strain-dependent activation of the ET-1 promoter, HBEGF shedding, and hBNP promoter activation. The metalloproteinase inhibitor, GM-6001, prevented the induction of HBEGF ectoshedding and the hBNP promoter response to strain, suggesting a critical role for the metalloproteinase-dependent cleavage event in signaling the strain response. These findings suggest that metalloproteinase activity as an essential step in this pathway may prove to be a relevant therapeutic target in the management of cardiac hypertrophy.

Topics: Animals; Cardiomegaly; Epidermal Growth Factor; ErbB Receptors; Gene Expression Regulation; MAP Kinase Signaling System; Mitogen-Activated Protein Kinases; Natriuretic Peptide, Brain; Rats; Signal Transduction; Stress, Mechanical; Transcriptional Activation

Cyclooxygenase (COX)-2 is expressed in the heart in animal models of ischemic injury. Recent studies have suggested that COX-2 products are involved in inflammatory cell infiltration and fibroblast proliferation in the heart. Using a mouse model, we questioned whether 1). myocardial infarction (MI) in vivo induces COX-2 expression chronically, and 2). COX-2 inhibition reduces collagen content and improves cardiac function in mice with MI. MI was produced by ligation of the left anterior descending coronary artery in mice. Two days later, mice were treated with 3 mg/kg NS-398, a selective COX-2 inhibitor, or vehicle in drinking water for 2 wk. After the treatment period, mice were subjected to two-dimensional M-mode echocardiography to determine cardiac function. Hearts were then analyzed for determination of infarct size, interstitial collagen content, brain natriuretic peptide (BNP) mRNA, myocyte cross-sectional area, and immunohistochemical staining for transforming growth factor (TGF)-beta and COX-2. COX-2 protein, detected by immunohistochemistry, was increased in MI versus sham hearts. MI resulted in increased left ventricular systolic and diastolic dimension and decreased ejection fraction, fractional shortening, and cardiac output. NS-398 treatment partly reversed these detrimental changes. Myocyte cross-sectional area, a measure of hypertrophy, was decreased by 30% in the NS-398 versus vehicle group, but there was no effect on BNP mRNA. The interstitial collagen fraction increased from 5.4 +/- 0.4% in sham hearts to 10.4 +/- 0.9% in MI hearts and was decreased to 7.9 +/- 0.6% in NS-398-treated hearts. A second COX-2 inhibitor, rofecoxib (MK-0966), also decreased myocyte cross-sectional area and interstitial collagen fraction. TGF-beta, a key regulator of collagen synthesis, was increased in MI hearts. NS-398 treatment reduced TGF-beta immunostaining by 40%. NS-398 treatment had no effect on infarct size. These results suggest that COX-2 products contribute to cardiac remodeling and functional deficits after MI. Thus selected inhibition of COX-2 may be a therapeutic target for reducing myocyte damage after MI.

Topics: Animals; Cardiomegaly; Collagen; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Dinoprostone; Echocardiography; Fibrosis; Heart; Immunohistochemistry; Isoenzymes; Lactones; Male; Mice; Mice, Inbred C57BL; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain; Nitrobenzenes; Prostaglandin-Endoperoxide Synthases; Reverse Transcriptase Polymerase Chain Reaction; Sulfonamides; Sulfones; Transforming Growth Factor beta

Adrenomedullin (AM) is a novel vasodilating peptide thought to have important effects on cardiovascular function. The aim of this study was to assess the activity of endogenous AM in the cardiovascular system using AM knockout mice.. Mice heterozygous for an AM-null mutation (AM+/-) and their wild-type littermates were subjected to aortic constriction or angiotensin II (Ang II) infusion. The resultant cardiovascular stress led to increases in heart weight/body weight ratios, left ventricular wall thickness, and perivascular fibrosis, as well as expression of genes encoding angiotensinogen, ACE, transforming growth factor-beta, collagen type I, brain natriuretic peptide, and c-fos. In addition, renal damage characterized by decreased creatinine clearance with glomerular sclerosis was noted. In all cases, the effects were significantly more pronounced in AM+/- mice. Hearts from adult mice subjected to aortic constriction showed enhanced extracellular signal-regulated kinase (ERK) activation, as did cardiac myocytes from neonates treated acutely with Ang II. Again the effect was more pronounced in AM+/- mice, which showed increases in cardiac myocyte size, protein synthesis, and fibroblast proliferation. ERK activation was suppressed by protein kinase C inhibition to a greater degree in AM+/- myocytes. In addition, treatment of cardiac myocytes with recombinant AM suppressed Ang II-induced ERK activation via a protein kinase A-dependent pathway.. Endogenous AM exerts a protective effect against stress-induced cardiac hypertrophy via protein kinase C- and protein kinase A-dependent regulation of ERK activation. AM may thus represent a useful new tool for the treatment of cardiovascular disease.

Topics: Adrenomedullin; Angiotensin II; Angiotensinogen; Animals; Aorta, Abdominal; Cardiomegaly; Collagen Type I; Constriction; Enzyme Activation; Enzyme Inhibitors; Fibroblasts; Fibrosis; Gene Expression Regulation; Genes, fos; Genes, Lethal; Glomerulosclerosis, Focal Segmental; Heterozygote; Male; MAP Kinase Signaling System; Mice; Mice, Knockout; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Myocytes, Cardiac; Natriuretic Peptide, Brain; Peptides; Peptidyl-Dipeptidase A; Protein Kinase C; Proto-Oncogene Proteins c-fos; Transforming Growth Factor beta; Ventricular Remodeling

To compare chest radiographic findings and circulating B-type natriuretic peptide (BNP) levels as an adjunct to clinical findings in the diagnosis of heart failure in patients presenting with acute dyspnea.. The diagnostic performance of radiographic evidence of cardiomegaly/redistribution and BNP levels > or =100 pg/mL as indicators of heart failure were assessed in 880 patients presenting with acute dyspnea to the emergency departments of five U.S. and two European teaching hospitals. BNP levels were determined by a rapid, point-of-care device. Two blinded cardiologists reviewed all clinical data and categorized patients as to whether they had acute heart failure (n = 447) or not (n = 433).. Three-factor analyses showed that BNP levels > or =100 pg/mL contributed significantly to the prediction of heart failure over each of the radiographic indicators. In a multivariate logistic regression analysis, both BNP levels > or =100 pg/mL (odds ratio [OR] = 12.3; 95% confidence interval [CI]: 7.4 to 20.4) and radiographic findings of cardiomegaly (OR = 2.3; 95% CI: 1.4 to 3.7), cephalization (OR = 6.4; 95% CI: 3.3 to 12.5), and interstitial edema (OR = 7.0; 95% CI: 2.9 to 17.0) added significant, predictive information above historical and clinical predictors of heart failure.. In patients presenting to the emergency department with acute dyspnea, BNP levels and chest radiographs provide complementary diagnostic information that may be useful in the early evaluation of heart failure.

Topics: Acute Disease; Biomarkers; Cardiomegaly; Dyspnea; Factor Analysis, Statistical; Female; Heart Failure; Humans; Logistic Models; Male; Middle Aged; Natriuretic Peptide, Brain; Radiography, Thoracic; Sensitivity and Specificity

In the present study, we examined whether NF-kappaB activation is required for cardiac hypertrophy in vivo. Cardiac hypertrophy in rats was induced by aortic banding for 1, 3, and 5 days and 1-6 wk, and age-matched sham-operated rats served as controls. In a separate group of rats, an IkappaB-alpha dominant negative mutant (IkappaB-alphaM), a superrepressor of NF-kappaB activation, or pyrrolidinedithiocarbamate (PDTC), an antioxidant that can inhibit NF-kappaB activation, was administered to aortic-banded rats for 3 wk. The heart weight-to-body weight ratio was significantly increased at 5 days after aortic banding, peaked at 4 wk, and remained elevated at 6 wk compared with age-matched sham controls. Atrial natriuretic peptide and brain natriuretic peptide mRNA expressions were significantly increased after 1 wk of aortic banding, reached a maximum between 2 and 3 wk, and remained increased at 6 wk compared with age-matched sham controls. NF-kappaB activity was significantly increased at 1 day, reached a peak at 3 wk, and remained elevated at 6 wk, and IKK-beta activity was significantly increased at 1 day, peaked at 5 days, and then decreased but remained elevated at 6 wk after aortic banding compared with age-matched sham controls. Inhibiting NF-kappaB activation in vivo by cardiac transfection of IkappaB-alphaM or by PDTC treatment significantly attenuated the development of cardiac hypertrophy in vivo with a concomitant decrease in NF-kappaB activity. Our results suggest that NF-kappaB activation is required for the development of cardiac hypertrophy in vivo and that NF-kappaB could be an important target for inhibiting the development of cardiac hypertrophy in vivo.

Topics: Adenoviridae; Animals; Antioxidants; Aorta; Atrial Natriuretic Factor; Cardiomegaly; I-kappa B Kinase; I-kappa B Proteins; Ligation; Male; Myocardium; Natriuretic Peptide, Brain; NF-kappa B; NF-KappaB Inhibitor alpha; Proline; Protein Serine-Threonine Kinases; Rats; Rats, Sprague-Dawley; RNA, Messenger; Signal Transduction; Thiocarbamates; Transfection

High levels of plasma atrial natriuretic peptides (ANP) are associated with pathological conditions such as congestive heart failure (CHF). Recently, we have identified a cardiac serine protease, corin, that is the pro-ANP convertase. In this study, we examined the regulation of corin gene expression in cultured hypertrophic cardiomyocytes and in the left ventricular (LV) myocardium of a rat model of heart failure. Quantitative RT-PCR analysis showed that both corin and ANP mRNA levels were significantly increased in phenylephrine (PE)-stimulated rat neonatal cardiomyocytes in culture. The increase in corin mRNA correlated closely with the increase in cell size and ANP mRNA expression in the PE-treated cells (r = 0.95, P < 0.01; r = 0.92, P < 0.01, respectively). The PE-treated cardiomyocytes had an increased activity in converting recombinant human pro-ANP to biologically active ANP, as determined by a pro-ANP processing assay and a cell-based cGMP assay. In a rat model of heart failure induced by ligation of the left coronary artery, corin mRNA expression in the noninfarcted LV myocardium was significantly higher than that of control heart tissues from sham-operated animals, when examined by Northern blot analysis and RT-PCR at 8 wk. These results indicate that the corin gene is upregulated in hypertrophic cardiomyocytes and failing myocardium. Increased corin expression may contribute to elevation of ANP in the setting of cardiac hypertrophy and heart failure.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Cells, Cultured; Gene Expression; Heart Failure; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats; RNA, Messenger; Serine Endopeptidases; Up-Regulation

The blockade of beta-adrenergic receptors reduces both mortality and morbidity in patients with chronic heart failure, but the cellular mechanism remains unclear. Celiprolol, a selective beta(1)-blocker, was reported to stimulate the expression of endothelial NO synthase (eNOS) in the heart, and NO levels have been demonstrated to be related to myocardial hypertrophy and heart failure. Thus, we aimed to clarify whether celiprolol attenuates both myocardial hypertrophy and heart failure via the NO-signal pathway.. In rat neonatal cardiac myocytes, celiprolol inhibited protein synthesis stimulated by either isoproterenol or phenylephrine, which was partially suppressed by N(G)-nitro-L-arginine methyl ester (L-NAME). Four weeks after transverse aortic constriction (TAC) in C57BL/6 male mice, the ratio of heart weight to body weight (mg/g) (8.70+/-0.42 in TAC, 6.61+/-0.44 with celiprolol 100 mg x kg(-1) x d(-1) PO, P<0.01) and the ratio of lung weight to body weight (mg/g) (10.27+/-1.08 in TAC, 7.11+/-0.70 with celiprolol 100 mg x kg(-1) x d(-1) PO, P<0.05) were lower and LV fractional shortening was higher in the celiprolol-treated groups than in the TAC group. All of these improvements were blunted by L-NAME. Celiprolol treatment significantly increased myocardial eNOS and activated phosphorylation of eNOS. Myocardial mRNA levels of natriuretic peptide precursor type B and protein inhibitor of NO synthase, which were increased in the TAC mice, were decreased in the celiprolol-treated mice.. These findings indicated that celiprolol attenuates cardiac myocyte hypertrophy both in vitro and in vivo and halts the process leading from hypertrophy to heart failure. These effects are mediated by a selective beta1-adrenergic receptor blockade and NO-dependent pathway.

Topics: Adrenergic beta-1 Receptor Antagonists; Adrenergic beta-Antagonists; Animals; Cardiomegaly; Celiprolol; Cells, Cultured; Disease Progression; Drug Evaluation, Preclinical; Enzyme Induction; Fibrosis; Gene Expression Regulation; Heart Failure; Hypertrophy; Isoproterenol; Male; Mice; Mice, Inbred C57BL; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Phenylephrine; Pressure; Rats; RNA, Messenger; Transcription, Genetic; Vasodilator Agents

The endoplasmic reticulum (ER) is recognized as an organelle that participates in folding secretory and membrane proteins. The ER responds to stress by upregulating ER chaperones, but prolonged and/or excess ER stress leads to apoptosis. However, the potential role of ER stress in pathophysiological hearts remains unclear.. Mice were subjected to transverse aortic constriction (TAC) or sham operation. Echocardiographic analysis demonstrated that mice 1 and 4 weeks after TAC had cardiac hypertrophy and failure, respectively. Cardiac expression of ER chaperones was significantly increased 1 and 4 weeks after TAC, indicating that pressure overload by TAC induced prolonged ER stress. In addition, the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells increased, and caspase-3 was cleaved in failing hearts. The antagonism of angiotensin II type 1 receptor prevented upregulation of ER chaperones and apoptosis in failing hearts. On the other hand, angiotensin II upregulated ER chaperones and induced apoptosis in cultured adult rat cardiac myocytes. We also investigated possible signaling pathways for ER-initiated apoptosis. The CHOP- (a transcription factor induced by ER stress), but not JNK- or caspase-12-, dependent pathway was activated in failing hearts by TAC. Pharmacological ER stress inducers upregulated ER chaperones and induced apoptosis in cultured cardiac myocytes. Finally, mRNA levels of ER chaperones were markedly increased in failing hearts of patients with elevated brain natriuretic peptide levels.. These findings suggest that pressure overload by TAC induces prolonged ER stress, which may contribute to cardiac myocyte apoptosis during progression from cardiac hypertrophy to failure.

Topics: Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Animals; Aortic Valve Stenosis; Apoptosis; Cardiomegaly; Cells, Cultured; Disease Models, Animal; Disease Progression; Endoplasmic Reticulum; Gene Expression Regulation; Heart Failure; Humans; Imidazoles; Ligation; Male; Mice; Mice, Inbred C57BL; Molecular Chaperones; Myocytes, Cardiac; Natriuretic Peptide, Brain; Olmesartan Medoxomil; Rats; Rats, Inbred WKY; RNA, Messenger; Signal Transduction; Stress, Physiological; Tetrazoles; Thapsigargin; Tunicamycin

Transgenic (tg) mice with chronic overexpression of the human erythropoietin gene are characterized by an increased hematocrit of about 0.80 in adulthood. This is accompanied by cardiac dysfunction and premature death. The aim of this study was to examine whether this cardiac dysfunction was accompanied by hypertrophy of the heart with remodeling of the extracellular matrix (ECM).. 3-months-old wild type (wt) and tg mice without cardiac hypertrophy were compared with the respective 7-months-old mice. The mRNA of brain natriuretic peptide (BNP), of the matrix metalloproteinases (MMP)-2, -8, -9, -13, of the tissue inhibitor of metalloproteinase (TIMP)-1, -2, -3, -4 and of collagen I and III was detected by ribonuclease protection assay. The activity of MMPs was measured by zymography.. There was hypertrophy of both ventricles in 7-months-old tg mice, which was accompanied by elevated mRNA expression of BNP. MMP-2 activity was increased and MMP-9 activity was decreased in the left ventricle (LV) of 3-months-old tg mice. This was accompanied by elevated TIMP-4 expression, followed by a shift of collagen mRNA expression from type III to type I in this ventricle.. The shift to collagen I in the heart of tg mice might be associated with a stiffer ventricle resulting in diastolic dysfunction. This may be responsible for a relative and intermittent LV- and right ventricle (RV)-insufficiency which was likely to have occurred as evidenced by the elevation of lung and liver weight with hemorrhage and interstitial fibrosis after 7 months.

Topics: Animals; Cardiomegaly; Collagen; Down-Regulation; Erythropoietin; Extracellular Matrix; Gene Expression; Heart Ventricles; Humans; Liver; Lung; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Matrix Metalloproteinases; Mice; Mice, Transgenic; Natriuretic Peptide, Brain; RNA, Messenger; Tissue Inhibitor of Metalloproteinase-4; Tissue Inhibitor of Metalloproteinases; Up-Regulation

Proteins of the LIM family are critical regulators of development and differentiation in various cell types. Here we examined the roles of one new member of LIM family, hhLIM, in cardiac hypertrophic growth and cardiac muscle-specific gene expression. To model the increase in endogenous hhLIM transcriptional activity that occurs in response to hypertrophic stimulation, hhLIM was overexpressed using a recombinant plasmid for hhLIM. The results showed that overexpression of hhLIM resulted in increased cell volume in both C2C12 muscle cells (>1.5-fold) and cardiac myocytes (>2.49-fold), a phenotype commonly associated with cardiac hypertrophy. RT-PCR and Western blot showed that transfection of hhLIM into C2C12 muscle cells and cardiomyocytes increased skeletal alpha-actin levels and triggered the expression of the embryonic-related gene BNP, which is associated with cardiac hypertrophy. Inhibition of hhLIM expression by antisense transcripts blocked the induction of skeletal alpha-actin and BNP expression by endothelin-1. These data indicated that hhLIM played a role in regulation of cardiomyocyte growth and cell size in response to hypertrophic stimuli through its modulation of skeletal alpha-actin and BNP expression. We also determined by confocal laser scanning microscopy and immunoprecipitation that hhLIM was associated with alpha-actin and localized in the cytoplasm in unstimulated cells, and was relocalized from the cytoplasm to the nucleus upon hypertrophic stimulation. These studies suggest that hhLIM protein is involved in cardiac hypertrophy.

Topics: Actins; Cardiomegaly; Carrier Proteins; Cell Nucleus; Cell Size; Cells, Cultured; Cytoplasm; Endothelin-1; Gene Expression; LIM Domain Proteins; Muscle Proteins; Myocytes, Cardiac; Natriuretic Peptide, Brain; Transfection

In spontaneously hypertensive rats a decrease occurs in myocardial energy supply from long-chain triglyceride (LCT) by CD36 gene mutation-induced dysfunction. We investigated whether long-term intake of medium-chain triglyceride, which enters into cells without CD36, upregulates fatty acid metabolic capacity in the heart of spontaneously hypertensive rats, and whether this upregulation improves cardiac hypertrophy and molecular markers. Male 4-week-old spontaneously hypertensive rats were given medium-chain triglyceride (SHR-MCT) or LCT (SHR-LCT) for 16 weeks. After hemodynamic measurement, we determined myocardial fatty acid metabolic enzyme activity and mRNA expression of molecular markers (endothelin-1, alpha-skeletal actin, angiotensin-converting enzyme and brain natriuretic peptide) for cardiac hypertrophy. We used Wistar-Kyoto rats (WKY-MCT and WKY-LCT) as controls. When compared with SHR-LCT rats, SHRMCT rats showed an increase in myocardial fatty acid metabolic enzyme activity and improvement in cardiac function (left ventricular end-diastolic pressure and +dP/dt/P) and cardiac hypertrophy. Blood pressure did not differ between them. The mRNA expression of endothelin-1, alpha-skeletal actin, angiotensin-converting enzyme and brain natriuretic peptide in the heart was significantly higher in SHR-LCT than in WKY-MCT and WKYLCT rats, and there was no significant difference between SHRLCT and SHR-MCT. These findings suggest that medium-chain triglyceride application to spontaneously hypertensive rats improves decreased cardiac function and cardiac hypertrophy without affecting blood pressure and myocardial mRNA expression of molecular markers. Because mechanical stress to the heart is similar between SHR-LCT and SHR-MCT, this may be a reason for the lack of difference in expression of molecular markers.

Topics: 3-Hydroxyacyl CoA Dehydrogenases; Actins; Animals; Blood Pressure; Cardiomegaly; Disease Models, Animal; Endothelin-1; Energy Metabolism; Heart Rate; Hypertension; Male; Myocardium; Natriuretic Peptide, Brain; Peptidyl-Dipeptidase A; Rats; Rats, Inbred SHR; Rats, Inbred WKY; RNA, Messenger; Time Factors; Triglycerides; Ventricular Function, Left; Ventricular Pressure

Brain natriuretic peptide (BNP) gene expression is a well documented marker of hypertrophy in the cardiac myocyte. Triiodothyronine (T(3)), the bioactive form of thyroid hormone, triggers a unique form of hypertrophy in cardiac myocytes that accompanies the selective activation or suppression of specific gene targets. In this study, we show that the BNP gene is a target of T(3) action. BNP secretion was increased 6-fold, BNP mRNA levels 3-fold, and BNP promoter activity 3-5-fold following T(3) treatment. This was accompanied by an increase in myocyte size, sarcomeric organization, and protein synthesis. Of note, several of the responses to T(3) synergized with those to the conventional hypertrophic agonist endothelin. The response to the liganded thyroid hormone receptor (TR) was mediated by an unusual thyroid hormone response element located between -1000 and -987 relative to the transcription start site. Both TR homodimers and TR.retinoid X receptor heterodimers associated with this element in an electrophoretic mobility shift assay. Protein fragments harboring the LXXLL motifs of the coactivators GRIP1 and SRC1 or TRAP220 interacted predominantly with the TR.retinoid X receptor heterodimeric pair in a ligand-dependent fashion. Both TR homodimers and heterodimers in the unliganded state selectively associated with glutathione S-transferase-nuclear receptor corepressor fragments harboring one of three receptor interaction domains containing the sequence (I/L)XX(I/V)I. These interactions were dissociated following the addition of T(3). Collectively, these findings identify the BNP gene as a potential model for the investigation of TR-dependent gene regulation in the heart.

Topics: Animals; Animals, Newborn; Cardiomegaly; Drug Synergism; Endothelins; Heart Ventricles; Myocytes, Cardiac; Natriuretic Peptide, Brain; Promoter Regions, Genetic; Rats; Receptors, Thyroid Hormone; Transcription, Genetic; Triiodothyronine; Up-Regulation

Atrial natriuretic peptide (ANP) prevents hypertrophy of neonatal cardiomyocytes. However, whether this effect is retained in the adult phenotype or if other members of the natriuretic peptide family exhibit similar antihypertrophic properties, has not been elucidated.. Our objective was to examine whether the natriuretic peptides protect against adult cardiomyocyte hypertrophy in vitro.. Adult rat cardiomyocytes were incubated with angiotensin II (Ang II)+/-ANP, B-type (BNP) or C-type (CNP) natriuretic peptides for determination of [3H]phenylalanine incorporation, c-fos mRNA expression and cyclic GMP. The effects of 8-bromo-cyclic GMP (cyclic GMP analogue), HS-142-1 (particulate guanylyl cyclase inhibitor) and KT5823 (cyclic GMP-dependent protein kinase inhibitor) were also investigated.. Ang II-stimulated increases in markers of hypertrophy, [3H]phenylalanine incorporation (to 136+/-3% of control, n=9) and c-fos mRNA expression (4.3+/-1.4-fold, n=5), were completely prevented by each of ANP, BNP or CNP. This protective action was accompanied by increased cardiomyocyte cyclic GMP. Inhibitory actions on [3H]phenylalanine incorporation were mimicked by 8-bromo-cyclic GMP, and were abolished by HS-142-1. KT5823 blocked the response to BNP and CNP, but not to ANP.. ANP prevents hypertrophy of adult rat cardiomyocytes. This protective action is shared by BNP and CNP and involves activation of particulate guanylyl cyclase receptors. Antihypertrophic effects of BNP and CNP are mediated through cyclic GMP-dependent protein kinase, but ANP can activate additional pathways independent of cyclic GMP to prevent adult cardiomyocte hypertrophy. These novel findings are of interest particularly since BNP appears to exert antifibrotic rather than antihypertrophic actions in vivo, while CNP is thought to act at least in part via the endothelium.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Cardiomegaly; Cyclic GMP; Drug Interactions; Guanylate Cyclase; Male; Muscle Cells; Natriuretic Peptide, Brain; Natriuretic Peptide, C-Type; Rats; Rats, Sprague-Dawley; Receptors, Atrial Natriuretic Factor

Mulibrey nanism is a rare inherited disease characterized by growth failure and multiorgan manifestations, including constrictive pericarditis. Its long-term course, the results of pericardiectomy, and the details of myocardial involvement have not been reported previously.. We studied 49 patients (26 men) born before 1985 and followed for up to 25 years. By 1999, 25 patients (51%) had developed congestive heart failure (CHF), 19 (39%) had undergone pericardiectomy for constrictive pericarditis, 10 (22%) had died of cardiac causes, and 5 (10%) had died of noncardiac causes. Of the 19 pericardiectomized patients, 12 derived lasting clinical benefit, whereas 1 patient suffered an early noncardiac death and 6 died later of unrelieved or recurrent CHF. At echocardiography in 34 living patients, left ventricular mass adjusted for body height and weight averaged (+/-SEM) 149+/-5 g in 21 unoperated patients, 144+/-8 g in 13 pericardiectomized patients, and 104+/-7 g in 16 healthy persons matched for age and sex (P=0.000). Autopsies of 11 patients showed fibrotic thickening of the pericardial leaves with myocardial hypertrophy and variable but mostly mild myocardial fibrosis. Endocardial thickening was seen in 3 patients.. Constrictive pericarditis, myocardial hypertrophy, and variable myocardial fibrosis constitute the main elements of Mulibrey heart disease. At least one half of patients ultimately develop CHF. Pericardiectomy generally provides clinical benefit, but in approximately one third of patients, CHF may recur because of coexisting myocardial involvement.

Topics: Adolescent; Adult; Aged; Cardiac Catheterization; Cardiomegaly; Disease Progression; Dwarfism; Echocardiography; Exercise Test; Female; Fibrosis; Follow-Up Studies; Heart Failure; Heart Function Tests; Humans; Male; Middle Aged; Myocardium; Natriuretic Peptide, Brain; Pericardiectomy; Pericarditis, Constrictive; Survival Rate; Time

This study tested the hypothesis that atrial natriuretic peptide has direct antihypertrophic actions on the heart by modulating expression of genes involved in cardiac hypertrophy and extracellular matrix production. Hearts of male, atrial natriuretic peptide-null and control wild-type mice that had been subjected to pressure overload after transverse aortic constriction and control unoperated hearts were weighed and subjected to microarray, Northern blot, and immunohistochemical analyses. Microarray and Northern blot analyses were used to identify genes that are regulated differentially in response to stress in the presence and absence of atrial natriuretic peptide. Immunohistochemical analysis was used to identify and localize expression of the protein products of these genes. Atrial natriuretic peptide-null mice demonstrated cardiac hypertrophy at baseline and an exaggerated hypertrophic response to transverse aortic constriction associated with increased expression of the extracellular matrix molecules periostin, osteopontin, collagen I and III, and thrombospondin, as well as the extracellular matrix regulatory proteins, matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-3, and the novel growth factor pleiotrophin compared with wild-type controls. These results support the hypothesis that atrial natriuretic peptide protects against pressure overload-induced cardiac hypertrophy and remodeling by negative modulation of genes involved in extracellular matrix deposition.

Topics: Animals; Aorta; Atrial Natriuretic Factor; Blood Pressure; Cardiomegaly; Constriction; Extracellular Matrix Proteins; Gene Expression Profiling; Immunohistochemistry; Male; Mice; Mice, Knockout; Myocardium; Natriuretic Peptide, Brain; Oligonucleotide Array Sequence Analysis; Organ Size; Pressure; Protein Precursors; RNA, Messenger

Grb2-associated binder-1 (Gab1) is a scaffolding/docking protein and contains a Pleckstrin homology domain and potential binding sites for Src homology (SH) 2 and SH3 domains. Gab1 is tyrosine phosphorylated and associates with protein tyrosine phosphatase SHP2 and p85 phosphatidylinositol 3-kinase on stimulation with various cytokines and growth factors, including interleukin-6. We previously demonstrated that interleukin-6-related cytokine, leukemia inhibitory factor (LIF), induced cardiac hypertrophy through gp130. In this study, we report the role of Gab1 in gp130-mediated cardiac hypertrophy. Stimulation with LIF induced tyrosine phosphorylation of Gab1, and phosphorylated Gab1 interacted with SHP2 and p85 in cultured cardiomyocytes. We constructed three kinds of adenovirus vectors, those carrying wild-type Gab1 (AdGab1WT), mutated Gab1 lacking SHP2 binding site (AdGab1F627/659), and beta-galactosidase (Adbeta-gal). Compared with cardiomyocytes infected with Adbeta-gal, longitudinal elongation of cardiomyocytes induced by LIF was enhanced in cardiomyocytes infected with AdGab1WT but inhibited in cardiomyocytes infected with AdGab1F627/659. Upregulation of BNP mRNA expression by LIF was evoked in cardiomyocytes infected with Adbeta-gal and AdGab1WT but not in cardiomyocytes infected with AdGab1F627/659. In contrast, Gab1 repressed skeletal alpha-actin mRNA expression through interaction with SHP2. Furthermore, activation of extracellular signal-regulated kinase 5 (ERK5) was enhanced in cardiomyocytes infected with AdGab1WT compared with cardiomyocytes infected with Adbeta-gal but repressed in cardiomyocytes infected with AdGab1F627/659. Coinfection of AdGab1WT with adenovirus vector carrying dominant-negative ERK5 abrogated longitudinal elongation of cardiomyocytes induced by LIF. Taken together, these findings indicate that Gab1-SHP2 interaction plays a crucial role in gp130-dependent longitudinal elongation of cardiomyoctes through activation of ERK5.

Topics: Actins; Adenoviridae; Animals; Antigens, CD; Atrial Natriuretic Factor; Binding Sites; Cardiomegaly; Cells, Cultured; Cytokine Receptor gp130; Gene Expression Regulation; Genes, Reporter; Genetic Vectors; Growth Inhibitors; Interleukin-6; Intracellular Signaling Peptides and Proteins; Leukemia Inhibitory Factor; Lymphokines; Membrane Glycoproteins; Mitogen-Activated Protein Kinase 7; Mitogen-Activated Protein Kinases; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phosphatidylinositol 3-Kinases; Phosphoproteins; Phosphorylation; Protein Binding; Protein Tyrosine Phosphatase, Non-Receptor Type 11; Protein Tyrosine Phosphatases; Rats; Rats, Wistar; RNA, Messenger; Signal Transduction; Transfection

The aims of this study were to measure the N-terminal fragment of pro-brain natriuretic peptide (proBNP) in plasma in medical conditions commonly found in primary care and to evaluate the utility of these measurements in identifying impaired cardiac function in elderly patients with symptoms associated with heart failure.. We studied 415 patients (221 men and 194 women; mean age, 72 years) who had contacted a primary healthcare center for dyspnea, fatigue, and/or peripheral edema. One cardiologist evaluated the patients in terms of history, physical examination, functional capacity, electrocardiography, and suspicion of heart failure. Plasma N-terminal proBNP was measured by an in-house RIA. An ejection fraction < or =40% by Doppler echocardiography was regarded as reduced cardiac function. Abnormal diastolic function was defined as an abnormal mitral inflow defined as reduced ratio of peak early diastolic filling velocity to peak filling velocity at atrial contraction (E/A ratio), or as abnormal pulmonary venous flow pattern.. Patients with impaired functional capacity, impaired systolic function, and/or impaired renal function had significantly increased N-terminal proBNP concentrations. By multiple regression analysis, N-terminal proBNP concentrations were also influenced by ischemic heart disease, cardiac enlargement, and certain medications but not by increased creatinine. No gender differences were observed. Patients with isolated diastolic dysfunction attributable to relaxation abnormalities had lower concentrations than those with normal cardiac function, whereas those with pseudonormal E/A ratios or restrictive filling patterns had higher concentrations.. Plasma N-terminal proBNP concentrations increase as a result of impaired systolic function, age, impaired renal function, cardiac ischemia and enlargement, and certain medications. Values are high in diastolic dysfunction with pseudonormal patterns, but not in patients with relaxation abnormalities. An increase in plasma N-terminal proBNP might be an earlier sign of abnormal cardiac function than abnormalities identified by currently used echocardiographic measurements.

Topics: Aged; Aged, 80 and over; Cardiomegaly; Diastole; Echocardiography, Doppler; Edema; Family Practice; Female; Heart Failure; Humans; Kidney; Male; Myocardial Ischemia; Natriuretic Peptide, Brain; Protein Precursors; Radiography; ROC Curve; Systole; Ventricular Dysfunction

Stimulation of cardiomyocyte guanosine 3',5'-cyclic monophosphate (cyclic GMP) via endothelial-derived nitric oxide (NO) is an important mechanism by which bradykinin and ACE inhibitors prevent hypertrophy. Endothelial NO dysfunction and cardiac hypertrophy are morbid features of diabetes not entirely prevented by ACE inhibitors. In cardiomyocyte/endothelial cell cocultures, bradykinin efficacy is abolished by high-glucose-induced endothelial NO dysfunction. We now demonstrate that antihypertrophic actions of natriuretic peptides, which stimulate cyclic GMP independently of NO, are preserved in cardiomyocytes despite high-glucose-induced endothelial dysfunction. Further, streptozotocin-induced diabetes significantly impairs the effectiveness of acute antihypertrophic strategies in isolated rat hearts. In hearts from citrate-treated control rats, angiotensin II-stimulated [(3)H]phenylalanine incorporation and atrial natriuretic peptide and beta-myosin heavy chain mRNA expression were prevented by B-type natriuretic peptide (BNP), bradykinin, the ACE inhibitor ramiprilat, and the neutral endopeptidase inhibitor candoxatrilat. These antihypertrophic effects were accompanied by increased left ventricular cyclic GMP. In age-matched diabetic hearts, the antihypertrophic and cyclic GMP stimulatory actions of bradykinin, ramiprilat, and candoxatrilat were absent. However, the blunting of hypertrophic markers and accompanying increases in cyclic GMP stimulated by BNP were preserved in diabetes. Thus BNP, which increases cyclic GMP independently of NO, is an important approach to prevent growth in the diabetic myocardium, where endothelium-dependent mechanisms are compromised.

Topics: Acute Disease; Animals; Atrial Natriuretic Factor; Cardiomegaly; Cells, Cultured; Chronic Disease; Cyclic GMP; Diabetes Mellitus, Experimental; Gene Expression; Heart Ventricles; Male; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phenylalanine; Rats; Rats, Sprague-Dawley; RNA, Messenger; Tritium

Electrical conductance is greatly altered in end-stage heart failure, but little is known about the underlying events. We therefore investigated the expression of genes coding for major inward and outward ion channels, calcium binding proteins, ion receptors, ion exchangers, calcium ATPases, and calcium/calmodulin-dependent protein kinases in explanted hearts (n=13) of patients diagnosed with end-stage heart failure. With the exception of Kv11.1 and Kir3.1 and when compared with healthy controls, major sodium, potassium, and calcium ion channels, ion transporters, and exchangers were significantly repressed, but expression of Kv7.1, HCN4, troponin C and I, SERCA1, and phospholamban was elevated. Hierarchical gene cluster analysis provided novel insight into regulated gene networks. Significant induction of the transcriptional repressor m-Bop and the translational repressor NAT1 coincided with repressed cardiac gene expression. The statistically significant negative correlation between repressors and ion channels points to a mechanism of disease. We observed coregulation of ion channels and the androgen receptor and propose a role for this receptor in ion channel regulation. Overall, the reversal of repressed ion channel gene expression in patients with implanted assist devices exemplifies the complex interactions between pressure load/stretch force and heart-specific gene expression.

Topics: Action Potentials; Adenosine Triphosphatases; Adrenergic beta-Antagonists; Antiporters; Atrial Natriuretic Factor; Calcium-Binding Proteins; Calcium-Calmodulin-Dependent Protein Kinases; Cardiac Output, Low; Cardiomegaly; Digitalis Glycosides; Electric Conductivity; Gene Expression Regulation; Heart-Assist Devices; Humans; Ion Channels; Myocytes, Cardiac; Natriuretic Peptide, Brain; Promoter Regions, Genetic; Repressor Proteins

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are cardiac hormones that regulate blood pressure and volume, and exert their biological actions via the natriuretic peptide receptor-A gene (Npr1). Mice lacking Npr1 (Npr(-/-)) have marked cardiac hypertrophy and fibrosis disproportionate to their increased blood pressure. This study examined the relationships between ANP and BNP gene expression, immunoreactivity and fibrosis in cardiac tissue, circulating ANP levels, and ANP and BNP mRNA during embryogenesis in Npr1(-/-) mice. Disruption of the Npr1 signaling pathway resulted in augmented ANP and BNP gene and ANP protein expression in the cardiac ventricles, most pronounced for ANP mRNA in females [414 +/- 57 in Npr1(-/-) ng/mg and 124 +/- 25 ng/mg in wild-type (WT) by Taqman assay, P < 0.001]. This increased expression was highly correlated to the degree of cardiac hypertrophy and was localized to the left ventricle (LV) inner free wall and to areas of ventricular fibrosis. In contrast, plasma ANP was significantly greater than WT in male but not female Npr1(-/-) mice. Increased ANP and BNP gene expression was observed in Npr1(-/-) embryos from 16 days of gestation. Our study suggests that cardiac ventricular expression of ANP and BNP is more closely associated with local hypertrophy and fibrosis than either systemic blood pressure or circulating ANP levels.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Cardiomyopathies; Embryo, Mammalian; Female; Fibrosis; Guanylate Cyclase; Heart Ventricles; Hypertension; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardium; Natriuretic Peptide, Brain; Receptors, Atrial Natriuretic Factor; Reference Values; RNA, Messenger

Recent investigation has focused on identifying signaling pathways that inhibit cardiac hypertrophy, a major risk factor for cardiovascular morbidity and mortality. In this context, nitric oxide (NO), signaling via cGMP and cGMP-dependent protein kinase type I (PKG I), has been recognized as a negative regulator of cardiac myocyte (CM) hypertrophy. However, the underlying mechanisms are poorly understood. Here, we show that PKG I inhibits CM hypertrophy by targeting the calcineurin-NFAT signaling pathway. Calcineurin, a Ca2+-dependent phosphatase, promotes hypertrophy in part by activating NFAT transcription factors which induce expression of hypertrophic genes, including brain natriuretic peptide (BNP). Activation of PKG I by NO/cGMP in CM suppressed NFAT transcriptional activity, BNP induction, and cell enlargement in response to alpha(1)-adrenoreceptor stimulation but not in response to adenoviral expression of a Ca2+-independent, constitutively active calcineurin mutant, thus demonstrating NO-cGMP-PKG I inhibition of calcineurin-NFAT signaling upstream of calcineurin. PKG I suppressed single L-type Ca2+-channel open probability, [Ca2+]i transient amplitude, and, most importantly, L-type Ca2+-channel current-induced NFAT activation, indicating that PKG I targets Ca2+-dependent steps upstream of calcineurin. Adenoviral expression of PKG I enhanced NO/cGMP inhibitory effects upstream of calcineurin, confirming that PKG I mediates NO/cGMP inhibition of calcineurin-NFAT signaling. In CM overexpressing PKG I, NO/cGMP also suppressed BNP induction and cell enlargement but not NFAT activation elicited by constitutively active calcineurin, which is consistent with additional, NFAT-independent inhibitory effect(s) of PKG I downstream of calcineurin. Inhibition of calcineurin-NFAT signaling by PKG I provides a framework for understanding how NO inhibits cardiac myocyte hypertrophy.

Topics: Animals; Animals, Newborn; Calcineurin; Calcineurin Inhibitors; Calcium Channels, L-Type; Calcium Signaling; Cardiomegaly; Cells, Cultured; Cyclic GMP; Cyclic GMP-Dependent Protein Kinase Type I; Cyclic GMP-Dependent Protein Kinases; DNA-Binding Proteins; Enzyme Activation; Heart; Heart Ventricles; Ion Channel Gating; Luciferases; Myocardium; Natriuretic Peptide, Brain; NFATC Transcription Factors; Nuclear Proteins; Plasmids; Probability; Promoter Regions, Genetic; Rats; Rats, Sprague-Dawley; Signal Transduction; Thionucleotides; Transcription Factors; Transcription, Genetic; Transfection

Endothelin-1 (ET-1) causes cardiac hypertrophy, and ET receptor antagonists inhibit the development of cardiac hypertrophy in vitro and in vivo. Peroxisome proliferator-activated receptor gamma (PPAR gamma), a member of the family of nuclear receptors, suppresses activator protein-1 (AP-1). We investigated the effects of the thiazolidinediones troglitazone and pioglitazone, activators of PPAR gamma, on cardiac hypertrophy due to pressure overload provoked by abdominal aortic banding (AB) in rats. Rats were divided into four groups: sham operation with vehicle treatment (n=5); AB surgery with vehicle treatment (n=6); AB surgery with troglitazone treatment (100 mg x kg(-1) x day(-1); n=5); and AB surgery with pioglitazone treatment (10 mg x kg(-1) x day(-1); n=8). Treatments were started 7 days before AB surgery, and left ventricular (LV) hypertrophy was assessed 24 h after surgery. The ratio of LV weight/body weight (BW) was significantly increased in AB rats compared with sham-operated rats; treatment of AB rats with troglitazone or pioglitazone significantly inhibited the increase in LV weight/BW. Expression of ET-1 mRNA was markedly enhanced in the left ventricles of AB rats; treatment with troglitazone or pioglitazone lowered expression significantly. Suppression of cardiac hypertrophy by pioglitazone treatment was accompanied by a decrease in expression of the gene encoding brain natriuretic factor, a molecular marker for cardiac hypertrophy, in AB rats. Because the ET-1 gene has AP-1 response elements in its 5'-flanking region, the thiazolidinediones troglitazone and pioglitazone may inhibit cardiac hypertrophy partly through suppression of AP-1-induced ET-1 gene up-regulation.

Topics: Analysis of Variance; Animals; Cardiomegaly; Chromans; Endothelin-1; Endothelins; Male; Natriuretic Peptide, Brain; Pioglitazone; Protein Precursors; Rats; Rats, Sprague-Dawley; Receptors, Cytoplasmic and Nuclear; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stimulation, Chemical; Thiazoles; Thiazolidinediones; Transcription Factors; Troglitazone

The calcium-activated phosphatase calcineurin has been implicated as a critical intracellular signal transducer of cardiomyocyte hypertrophy. Although previous data suggested the nuclear factor of activated T-cells (NFAT) as its sole transcriptional effector, the absolute requirement of NFAT as a mediator of calcineurin signaling has not been examined in the heart. We therefore investigated the expression and activation profile of NFAT genes in the heart. Four members (NFATc1-c4) are expressed in cardiomyocytes, elicit nuclear translocation upon calcineurin activation, and are able to drive transactivation of cardiac promoter luciferase constructs. To define the necessary function of NFAT factors as hypertrophic transducers, a dominant negative NFAT construct was created, encompassing part of the N-terminal region of NFATc4 containing a conserved calcineurin-binding motif. Cotransfection of this construct dose-dependently abrogated promoter activation, irrespective of the NFAT isoform used, whereas a control construct with the calcineurin-binding motif mutated displayed no such effects. Adenoviral gene transfer of dominant negative NFAT rendered cardiomyocytes resistant toward all aspects of calcineurin or agonist-induced cardiomyocyte hypertrophy, whereas adenoviral gene transfer of the control construct had no discernable effect on these parameters. These results indicate that multiple NFAT isoforms are expressed in cardiomyocytes where they function as necessary transducers of calcineurin in facilitating cardiomyocyte hypertrophy.

Topics: Animals; Base Sequence; Calcineurin; Cardiomegaly; Cell Nucleus; DNA Primers; DNA-Binding Proteins; GATA4 Transcription Factor; Gene Expression Profiling; Gene Expression Regulation; Mice; Natriuretic Peptide, Brain; NFATC Transcription Factors; Nuclear Proteins; Protein Isoforms; Protein Transport; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Transcription Factors

Guanylyl cyclase (GC)-A, a natriuretic peptide receptor, lowers blood pressure and inhibits the growth of cardiac myocytes and fibroblasts. Angiotensin II (Ang II) type 1A (AT1A), an Ang II receptor, regulates cardiovascular homeostasis oppositely. Disruption of GC-A induces cardiac hypertrophy and fibrosis, suggesting that GC-A protects the heart from abnormal remodeling. We investigated whether GC-A interacts with AT1A signaling in the heart by target deletion and pharmacological blockade or stimulation of AT1A in mice.. We generated double-knockout (KO) mice for GC-A and AT1A by crossing GC-A-KO mice and AT1A-KO mice and blocked AT1 with a selective antagonist, CS-866. The cardiac hypertrophy and fibrosis of GC-A-KO mice were greatly improved by deletion or pharmacological blockade of AT1A. Overexpression of mRNAs encoding atrial natriuretic peptide, brain natriuretic peptide, collagens I and III, transforming growth factors beta1 and beta3, were also strongly inhibited. Furthermore, stimulation of AT1A by exogenous Ang II at a subpressor dose significantly exacerbated cardiac hypertrophy and dramatically augmented interstitial fibrosis in GC-A-KO mice but not in wild-type animals.. These results suggest that cardiac hypertrophy and fibrosis of GC-A-deficient mice are partially ascribed to an augmented cardiac AT1A signaling and that GC-A inhibits AT1A signaling-mediated excessive remodeling.

Topics: Angiotensin II; Angiotensin Receptor Antagonists; Angiotensinogen; Animals; Atrial Natriuretic Factor; Blood Pressure; Body Weight; Cardiomegaly; Collagen; Fibrosis; Gene Targeting; Guanylate Cyclase; Heart Rate; Heart Ventricles; Hypertension; Imidazoles; Mice; Mice, Knockout; Myocardium; Natriuretic Peptide, Brain; Olmesartan Medoxomil; Organ Size; Peptidyl-Dipeptidase A; Receptor, Angiotensin, Type 1; Receptors, Angiotensin; Receptors, Atrial Natriuretic Factor; RNA, Messenger; Tetrazoles; Transforming Growth Factor beta; Transforming Growth Factor beta1; Transforming Growth Factor beta2; Ventricular Remodeling

The activator protein 1 (AP-1) transcriptional complex, containing Jun and Fos proteins, is involved in regulating many cellular processes such as proliferation and differentiation. However, little is known about a direct relationship between AP-1 activities and cardiomyocyte hypertrophy. To elucidate the roles of myocardial AP-1 activities, dominant negative mutant of c-Jun (DNJun) was overexpressed in cultured rat neonatal ventricular myocytes by adenovirus vector to abrogate endogenous AP-1 activation. Cardiomyocytes were treated with 100 nmol/L endothelin 1 (ET) and 10 micromol/L phenylephrine (PE) to induce myocardial cell hypertrophy. Both ET and PE significantly enhanced AP-1 DNA binding activities (3.4-fold by ET and 4.8-fold by PE at 3 hours, P<0.01). At 48 hours after stimulation, ET and PE significantly increased incorporation of (3)H-phenylalanine (1.4-fold by ET and 1.5-fold by PE, P<0.01), cell size (2.3-fold and 2.5-fold, P<0.01), and mRNA expression of atrial natriuretic peptide (ANP; 1.9-fold and 1.8-fold, P<0.01) and brain natriuretic peptide (BNP; 1.6-fold and 1.6-fold, P<0.01). Adenovirus carrying DNJun prevented the transcriptional activation of the AP-1 by ET and PE, using AP-1 reporter enzyme firefly luciferase assay. Moreover, DNJun prevented the increase in incorporation of (3)H-phenylalanine, cell size, and the mRNA expression of ANP and BNP by ET and PE. In conclusion, we provide the first evidence that DNJun inhibits cardiomyocyte hypertrophy through inhibition of AP-1 transcriptional activity.

Topics: Adenoviridae; Animals; Atrial Natriuretic Factor; Cardiomegaly; Cell Size; Cells, Cultured; DNA, Complementary; Endothelin-1; Genes, Dominant; Genes, jun; Heart Ventricles; Lac Operon; Mutation; Myocardium; Natriuretic Peptide, Brain; Phenylephrine; Proto-Oncogene Proteins c-jun; Rats; Rats, Wistar; Transcription Factor AP-1; Transcriptional Activation; Transfection

GATA-4 transcription factor is required for normal cardiac development. However, it is unknown whether GATA-4 is an essential mediator of hypertrophic responses in the heart. Rat B-type natriuretic peptide (BNP) gene promoter contains a region of two adjacent GATA binding sites (between -68 and -97) with high affinity for GATA-4. In order to block GATA-4 dependent signaling in cultured neonatal rat ventricular myocytes we administered a synthetic 30-bp phosphorothioated double-stranded DNA complementary to the rat BNP promoter region (between -68 and -97) as a "decoy" cis-element to bind GATA-4. GATA decoy oligodeoxynucleotide treatment of cardiomyocytes blocked GATA-4 DNA binding activity in electrophoretic mobility shift analysis and decreased baseline expression of cardiac natriuretic peptides and GATA-dependent promoter activity. In contrast, blocked GATA-4 DNA binding did not prevent endothelin-1 or phenylephrine induced expression of cardiac natriuretic peptides. Mutation of GATA binding sites at -80 and -91 rat BNP promoter downregulated baseline but did not affect endothelin-1 or angiotensin II induced promoter activity. Additively, GATA decoy oligodeoxynucleotide treatment was insufficient to block endothelin-1 induced activation of protein synthesis or sarcomeric protein assembly. In conclusion, a targeted disruption of GATA-4 DNA binding activity is insufficient to prevent hypertrophic agonist induced responses of ventricular myocytes.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Binding Sites; Cardiomegaly; DNA-Binding Proteins; Endothelin-1; GATA4 Transcription Factor; Gene Expression Regulation; Myocardium; Natriuretic Peptide, Brain; Oligodeoxyribonucleotides; Phenylephrine; Promoter Regions, Genetic; Protein Binding; Rats; Transcription Factors

Topics: Atrial Natriuretic Factor; Cardiomegaly; Humans; Natriuretic Peptide, Brain; Receptors, Atrial Natriuretic Factor

We examined whether Ca2+ channel blockers inhibit the activation of the Ca2+-dependent phosphatase calcineurin and the development of cardiac hypertrophy in spontaneously hypertensive rats (SHR). We randomly divided 12-week-old SHR into three groups, one each receiving vehicle, bolus injection or continuous infusion of nifedipine (10 mg/kg/day) from 12 to 24 weeks of age. Systolic blood pressure (BP) and heart rate were measured every week after the treatment using the tail-cuff plethysmography method. After 4, 8 and 12 weeks of treatment, 6 rats of each group were subjected to examinations that included an assay for calcineurin activity in the heart, magnetic resonance imaging (MRI), histology and Northern blot analysis. Continuous infusion of nifedipine consistently reduced BP, whereas bolus injection resulted in a fluctuation of BP. Continuous infusion of nifedipine not only reduced left ventricular mass but also decreased the transverse diameter of cardiomyocytes, interstitial fibrosis and the expression of the atrial natriuretic peptide and brain natriuretic peptide genes in the heart, while bolus injection of nifedipine did not significantly attenuate any of these hypertrophic responses in SHR. The activity of calcineurin in the heart was strongly suppressed by continuous but not bolus infusion of nifedipine in SHR. The results indicate that continuous blockade of Ca2+ channels with nifedipine effectively suppresses the development of cardiac hypertrophy in SHR, possibly through inhibition of the calcineurin activity.

Topics: Animals; Atrial Natriuretic Factor; Blood Pressure; Calcineurin Inhibitors; Calcium Channel Blockers; Calcium Channels, L-Type; Cardiomegaly; Fibrosis; Gene Expression; Heart Rate; Hypertension; Male; Myocardium; Natriuretic Peptide, Brain; Nifedipine; Rats; Rats, Inbred SHR

Atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) regulate cardiac hypertrophy. We investigated ventricular alterations of ANP and BNP in interleukin-6 (IL-6) transgenic mice (TG) and wild type (WT) mice with or without viral infection. The ANP and BNP mRNA/GAPDH mRNA ratios in the ventricles of IL-6 TG mice were twice that of WT mice, but were not increased significantly by viral inoculation. In WT mice, both ANP and BNP responses were significantly increased in the ventricles of mice 10 days after encephalomyocarditis (EMC) viral inoculation. Cardiac weight in IL-6 TG mice was significantly greater than in WT 10 days after viral inoculation. Left ventricular wall thickness and the diameter of ventricular myocytes also were greater in IL-6 TG than WT after viral infection. Primary cultures of neonatal rat cardiac myocyte showed that IL-6 increased ANP and BNP mRNA expression in a dose-responsive fashion. In summary, overexpression of ANP and BNP occurs in the ventricles of IL-6 TG mice, along with increased cardiac weight after infection with EMC virus, and impaired responses in the expression of ANP and BNP.

Topics: Animals; Atrial Natriuretic Factor; Body Weight; Cardiomegaly; DNA Probes; Encephalomyocarditis virus; Interleukin-6; Mice; Mice, Inbred C57BL; Mice, Transgenic; Natriuretic Peptide, Brain; Organ Size; Rats

The relationship was investigated between coronary flow reserve and Doppler echocardiographic parameters, hemodynamic parameters and plasma natriuretic peptide concentrations in the hypertrophied heart.. The subjects were 19 patients with hypertrophied heart due to various etiologies and no significant coronary artery stenosis. All patients were in sinus rhythm. The left ventricular wall thickness, the E/A ratio in transmitral flow velocity pattern and the Doppler index were determined by Doppler echocardiography, and the plasma atrial and brain natriuretic peptide concentrations were measured. At cardiac catheterization, pulmonary capillary wedge pressure and left ventricular end-diastolic pressure were measured, and the coronary flow reserve was obtained by injecting intracoronary adenosine triphosphate into the left anterior descending artery using a Doppler guidewire.. Coronary flow reserve in the patients was significantly lower than in 11 normal control subjects (2.50 +/- 0.76 vs 3.90 +/- 0.64, p < 0.001). There were no significant correlations between coronary flow reserve and the left ventricular wall thickness or the E/A ratio. The mean value of the Doppler index in the patients was 0.48 +/- 0.10 and there was a significant negative correlation between coronary flow reserve and the Doppler index (r = -0.73, p < 0.001). The correlation between coronary flow reserve and left ventricular end-diastolic pressure was not significant, but there was a significant negative correlation between coronary flow reserve and pulmonary capillary wedge pressure (r = -0.64, p < 0.01). There were significant negative correlations between coronary flow reserve and atrial (r = -0.62, p < 0.01), or brain natriuretic peptide concentrations (r = -0.56, p < 0.05).. Coronary flow reserve may reflect overall cardiac performance evaluated by the Doppler index and plasma natriuretic peptide concentrations in the hypertrophied heart, and the measurement of coronary flow reserve may be useful for evaluating disease severity in patients with hypertrophied heart.

Topics: Aged; Atrial Natriuretic Factor; Blood Flow Velocity; Cardiomegaly; Coronary Circulation; Echocardiography, Doppler; Female; Heart Function Tests; Hemodynamics; Humans; Male; Middle Aged; Natriuretic Peptide, Brain; Severity of Illness Index

Peroxisome proliferator-activated receptors (PPARs) are transcription factors belonging to the nuclear receptor superfamily. PPARgamma mRNA is present in cardiac myocytes; however, whether PPARgamma affects cardiac hypertrophy remains unknown.. We investigated the effects of PPARgamma activators on cardiac hypertrophy in neonatal rat cardiac myocytes. Cyclic 4% biaxial mechanical strain caused enlargement of cardiac myocytes (1.3-fold versus control, P<0.0001), but the PPARgamma activators troglitazone and 15-deoxy-Delta(12-14)-prostaglandin J(2) (15d-PGJ(2)) (10 micromol/L) inhibited this effect (troglitazone, -72%, P<0.0005; 15d-PGJ(2), -88%, P<0.0002). Total cell protein was increased by mechanical strain (control, 164.3 microgram/dish; strain, 265.5, P<0.0002), and this effect was inhibited by troglitazone and 15d-PGJ(2) (troglitazone, -61%, P<0.005; 15d-PGJ(2), -72%, P<0.001). [(3)H]Leucine uptake was also increased by mechanical strain (1.9-fold versus control, P<0.002), and this increase was inhibited by troglitazone and 15d-PGJ(2) (troglitazone, -52% at 10 micromol/L, P<0.01; 15d-PGJ(2), -70% at 10 micromol/L, P<0.005). An increase in [(3)H]leucine uptake induced by angiotensin II or phenylephrine was significantly inhibited by troglitazone and 15d-PGJ(2). Mechanical strain induced mRNA expression for brain natriuretic peptide, but PPARgamma activators inhibited this induction. Furthermore, PPARgamma activators inhibited mechanically induced activation of nuclear factor (NF)-kappaB. Pyrrolidine dithiocarbamate, an inhibitor of NF-kappaB activation, inhibited strain-induced [(3)H]leucine uptake (-50% at 100 micromol/L, P<0.05).. These results demonstrate that PPARgamma activators inhibit cardiac hypertrophy in cardiac myocytes and suggest that PPARgamma activators may regulate cardiomyocyte hypertrophy at least partially through the NF-kappaB pathway.

Topics: Angiotensin II; Animals; Animals, Newborn; Biological Transport; Cardiomegaly; Cells, Cultured; Chromans; Heart; Leucine; Myocardium; Natriuretic Peptide, Brain; NF-kappa B; Phenylephrine; Prostaglandin D2; Rats; Receptors, Cytoplasmic and Nuclear; RNA, Messenger; Stress, Mechanical; Thiazoles; Thiazolidinediones; Transcription Factors; Troglitazone

Recently, deletion of specific genes by so called knock-out techniques has become important for investigating the pathogenesis of various diseases. This form of genetic engineering is widely performed in murine models. There are, however, only a limited number of mouse models available in cardiovascular pathology. The objective of this study, therefore, was to develop a new model of overt congestive heart failure associated with myocardial hypertrophy in the mouse.. Female C57/BL6 mice weighing 19-20 g were anesthetized with ether. After abdominal incision, the aorta was temporarily clamped proximal to the renal arteries. The aorta was then punctured with a needle (outer diameter 0.6 mm) and the needle was further advanced into the adjacent vena cava. After withdrawal of the needle, the aortic puncture site was sealed with cyanoacrylate glue. The clamp was removed, and the patency of the shunt was visually verified as swelling and mixing of venous and arterial blood in the vena cava. Sham-operated mice served as controls.. Perioperative mortality of mice with aortocaval shunt was 42%. Four weeks after shunt induction, mice showed a significant cardiac hypertrophy with a relative heart weight of 7.5+/-0.2 mg/100 g body weight (vs. 5.1+/-0.7 mg/100 g in control mice, P<0.001). While no changes in blood pressure and heart rate occurred, left ventricular enddiastolic pressure was significantly increased in mice with shunt, and left ventricular contractility was impaired from 6331+/-412 to 4170+/-296 mmHg/s (P<0.05). Plasma concentrations of atrial natriuretic peptide (ANP) and its second messenger cGMP as humoral markers of heart failure as well as ventricular expression of ANP- and brain natriuretic peptide (BNP)-mRNA were significantly increased in mice with shunt compared to control mice.. The aortocaval shunt in the mouse constitutes a new model of overt congestive heart failure with impaired hemodynamic parameters and may be a useful tool to investigate the role of particular genes in the development of heart failure.

Topics: Animals; Arteriovenous Shunt, Surgical; Atrial Natriuretic Factor; Blood Pressure; Cardiac Volume; Cardiomegaly; Disease Models, Animal; Female; Heart Failure; Heart Rate; Mice; Mice, Inbred C57BL; Natriuretic Peptide, Brain

Topics: Amlodipine; Antihypertensive Agents; Atenolol; Atrial Natriuretic Factor; Bendroflumethiazide; Cardiomegaly; Endothelin-1; Female; Heart Failure; Humans; Hypertension; Male; Middle Aged; Natriuretic Peptide, Brain; Perindopril; Procollagen; Randomized Controlled Trials as Topic

Pressure overload, such as hypertension, to the heart causes pathological cardiac hypertrophy, whereas chronic exercise causes physiological cardiac hypertrophy, which is defined as athletic heart. There are differences in cardiac properties between these two types of hypertrophy. We investigated whether mRNA expression of various cardiovascular regulating factors differs in rat hearts that are physiologically and pathologically hypertrophied, because we hypothesized that these two types of cardiac hypertrophy induce different molecular phenotypes. We used the spontaneously hypertensive rat (SHR group; 19 wk old) as a model of pathological hypertrophy and swim-trained rats (trained group; 19 wk old, swim training for 15 wk) as a model of physiological hypertrophy. We also used sedentary Wistar-Kyoto rats as the control group (19 wk old). Left ventricular mass index for body weight was significantly higher in SHR and trained groups than in the control group. Expression of brain natriuretic peptide, angiotensin-converting enzyme, and endothelin-1 mRNA in the heart was significantly higher in the SHR group than in control and trained groups. Expression of adrenomedullin mRNA in the heart was significantly lower in the trained group than in control and SHR groups. Expression of beta(1)-adrenergic receptor mRNA in the heart was significantly higher in SHR and trained groups than in the control group. Expression of beta(1)-adrenergic receptor kinase mRNA, which inhibits beta(1)-adrenergic receptor activity, in the heart was markedly higher in the SHR group than in control and trained groups. We demonstrated for the first time that the manner of mRNA expression of various cardiovascular regulating factors in the heart differs between physiological and pathological cardiac hypertrophy.

Topics: Actins; Adrenomedullin; Animals; Blood Pressure; Body Weight; Cardiomegaly; Disease Models, Animal; Gene Expression Regulation; Hemodynamics; Natriuretic Peptide, Brain; Peptides; Peptidyl-Dipeptidase A; Phenotype; Physical Conditioning, Animal; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptor, Muscarinic M2; Receptors, Adrenergic, beta-1; Receptors, Muscarinic; Reference Values; Swimming; Transcription, Genetic

Urotensin II (UII), a cyclic neuropeptide, functions not only in the central nervous system but also in non-neural systems including cardiovascular systems. In the present study we examined whether UII regulates hypertrophy in cardiomyocytes. The exposure of cultured cardiomyocytes from neonatal rats to UII dose-dependently activated extracellular signal-regulated kinases (ERKs), important molecules in the development of cardiac hypertrophy. ERK activation by UII at 100 nM peaked at 8 min after stimulation. UII markedly induced expression of specific genes encoding atrial natriuretic peptide and brain natriuretic peptide, and significantly increased amino acid incorporation into proteins. Incubation of cardiomyocytes with UII increased cell size and myofibril organisation. UII, then, might participate in cardiomyocyte hypertrophy.

Topics: Animals; Animals, Newborn; Atrial Natriuretic Factor; Cardiomegaly; Cell Size; Cells, Cultured; Enzyme Activation; Gene Expression; Heart; Humans; Microscopy, Fluorescence; Mitogen-Activated Protein Kinases; Myocardium; Natriuretic Peptide, Brain; Phenylalanine; Protein Biosynthesis; Rats; Rats, Wistar; Urotensins

We examined whether adrenomedullin (AM), a vasoactive peptide with significant expression and binding sites in the heart, modulates the hypertrophic response in cultured neonatal rat ventricular myocytes. Myocyte hypertrophy was induced by treating the cells with angiotensin II (Ang II), endothelin-1 (ET-1) or alpha-adrenergic agonist, L-phenylephrine (PHE). All treatments resulted in a hypertrophic response as reflected by increased protein synthesis and expression of atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) genes. AM treatment resulted in a complete inhibition of the Ang II-induced increase in ANP and BNP gene expression and secretion. In contrast, no inhibitory effect was seen in either ET-1-induced natriuretic peptide gene expression or PHE-induced ANP and BNP gene expression and secretion. AM had only a modest effect on basal levels of natriuretic peptide secretion and gene expression. When AM mRNA levels in isolated neonatal rat myocytes treated for 48 h with Ang II, ET-1 or PHE were measured, only Ang II induced a consistent increase in AM gene expression. These results indicate that AM is not invariably associated with attenuation of the hypertrophic response but its effect is dependent on the stimulus activating myocyte hypertrophy. AM may form an important autocrine/paracrine growth-inhibitory loop in Ang II-induced myocyte hypertrophy.

Topics: Adrenomedullin; Angiotensin II; Animals; Atrial Natriuretic Factor; Cardiomegaly; Cyclic AMP; Cyclic GMP; Drug Interactions; Endothelin-1; Gene Expression; Heart; Heart Ventricles; In Vitro Techniques; Myocardium; Natriuretic Peptide, Brain; Peptides; Phenylephrine; Rats; Sarcomeres

Atrial natriuretic peptide (ANP) may function as an endogenous regulator of cardiac hypertrophy, because the natriuretic peptide receptor has been found in the heart and because mice lacking its receptor have been shown to have a markedly elevated ventricular mass. We examined the role of endogenous ANP in cardiac hypertrophy in vitro. The effects of the blockade of endogenous ANP by its receptor antagonist, HS-142-1, on cell hypertrophy were investigated with the use of cultured neonatal rat ventricular myocytes. HS-142-1 increased the basal and phenylephrine (PE, 10(-5) mol/L)-stimulated protein syntheses in a concentration-dependent manner (1 to 300 microg/mL). A significant increase in the cell size of myocytes was also induced by this antagonist. In addition, the expression levels of skeletal alpha-actin, beta-myosin heavy chain, and ANP genes, markers of hypertrophy, were partially elevated by treatment with HS-142-1 (100 microg/mL) under nonstimulated or PE-stimulated conditions. A cGMP-specific phosphodiesterase inhibitor, zaprinast (5x10(-4) mol/L), and a cGMP analogue (10(-4) mol/L) suppressed the basal and PE-stimulated protein syntheses. Our observations suggest that endogenous ANP inhibits cardiac myocyte hypertrophy under basal and PE-stimulated conditions, probably through a cGMP-dependent process. ANP may play a role as an autocrine factor in the regulation of cardiac myocyte growth.

Topics: Actins; Animals; Atrial Natriuretic Factor; Cardiomegaly; Cell Size; Cells, Cultured; Gene Expression; Mice; Myocardium; Myosin Heavy Chains; Natriuretic Peptide, Brain; Phenylephrine; Polysaccharides; Protein Biosynthesis; Rats; RNA, Messenger

We have shown that interleukin-1beta (IL-1beta) activates the human brain natriuretic peptide (hBNP) promoter via a transcriptional mechanism. Others have reported that changes in intracellular calcium (Ca(2+)) mediate the action of IL-1beta. We questioned whether Ca(2+) and Ca(2+)-dependent pathways mediate IL-1beta regulation of the hBNP promoter in cardiac myocytes. The hBNP promoter (-1818 to +100) coupled to a luciferase cDNA reporter gene was transferred into neonatal cardiac myocytes. Cells were then treated with agents that modify Ca(2+) levels or inhibit Ca(2+)-dependent kinases, and luciferase activity was measured as an index of hBNP promoter activity. The Ca(2+) ionophore A23187 increased hBNP promoter activity; however, neither EGTA nor nifedipine reduced IL-1beta-stimulated promoter activity. Long-term treatment with thapsigargin, which depletes intracellular Ca(2+) stores, decreased basal promoter activity and blocked the effect of IL-1beta. Inhibition of protein kinase C completely blocked IL-1beta-stimulated hBNP promoter activity, whereas inhibition of Ca(2+)/calmodulin-dependent kinase II decreased promoter activity by 40%. In contrast, inhibition of the Ca(2+)-regulated phosphatase calcineurin by cyclosporin A had no effect. These data suggest that (1) Ca(2+) activates the hBNP promoter; (2) release of Ca(2+) from intracellular stores is important to IL-1beta regulation of the hBNP promoter, but transport via voltage-sensitive Ca(2+) channels is not; (3) protein kinase C and Ca(2+)/calmodulin-dependent kinase II mediate the action of IL-1beta; and (4) the phosphatase calcineurin is not involved in IL-1beta regulation of the hBNP promoter. Thus, Ca(2+) and Ca(2+)-dependent pathways are critical to IL-1beta regulation of the hBNP promoter.

Topics: Animals; Calcineurin; Calcium; Calcium Signaling; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Calcium-Calmodulin-Dependent Protein Kinases; Cardiomegaly; Cells, Cultured; Gene Expression Regulation, Enzymologic; Heart Ventricles; Humans; Interleukin-1; MAP Kinase Signaling System; Myocardium; Natriuretic Peptide, Brain; Promoter Regions, Genetic; Protein Kinase C; Rats; Rats, Sprague-Dawley; Transfection

The overexpression of either oncogenic ras or calmodulin in cardiac myocytes can elicit a hypertrophic response, albeit their recruitment by physiologically relevant stimuli remains unresolved. The present study utilized a pharmacological approach to examine the role of ras and calmodulin in norepinephrine- and endothelin-1-stimulated hypertrophy of neonatal rat cardiac myocytes. The pretreatment of cardiac myocytes with the farnesyltransferase inhibitor BMS-191563 (25 microM) increased the level of unfarnesylated ras in the cytosolic fraction, and caused a concomitant 42 +/- 2% decrease in immunodetectable farnesylated ras in the particulate fraction. In parallel, BMS-191563 pretreatment inhibited norepinephrine-mediated 3H-leucine uptake (80 +/- 10% decrease: n = 6; P<0.01), whereas a significant but less pronounced effect on the endothelin-1 response (46 +/- 6% decrease: n = 6; P<0.05) was observed. The calmodulin inhibitor W7 caused a 50 +/- 10% decrease (n = 8; P<0.05) of norepinephrine stimulated protein synthesis, whereas the endothelin-1 response was unaffected. Consistent with the recruitment of ras, BMS-191563 pretreatment attenuated norepinephrine and endothelin-1-stimulated extracellular signal-regulated kinase (ERK) activity. However, PD098059-mediated inhibition of MEK-dependent stimulation of ERK did not alter the hypertrophic response of either agonist. At the molecular level, the pretreatment with either BMS-191563 or W7 attenuated the norepinephrine-mediated increase of prepro-ANP and -BNP mRNA. Likewise, BMS-191563 caused a significant decrease of endothelin-1-mediated expression of the natriuretic peptide mRNAs, but to a lesser extent, as compared to norepinephrine. Thus, the present study has shown the treatment of neonatal rat cardiac myocytes with a farnesyltransferase inhibitor can attenuate the hypertrophic phenotype in response to physiologically relevant stimuli, thereby supporting a role of the small GTP-binding protein ras. Moreover, these data further suggest alternative ras-independent signaling pathways are also implicated in the hypertrophic response, albeit, there appears to exist a stimulus-specific heterogeneity in their recruitment.

Topics: Alkyl and Aryl Transferases; Animals; Atrial Natriuretic Factor; Calmodulin; Cardiomegaly; Cells, Cultured; Endothelin-1; Enzyme Activation; Enzyme Inhibitors; Farnesyltranstransferase; Gene Expression; Heart; Mitogen-Activated Protein Kinases; Myocardium; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Norepinephrine; Protein Precursors; ras Proteins; Rats; Rats, Sprague-Dawley; RNA, Messenger; Sulfonamides

CARP, a cardiac doxorubicin (adriamycin)-responsive protein, has been identified as a nuclear protein whose expression is downregulated in response to doxorubicin. In the present study, we tested the hypothesis that CARP serves as a reliable genetic marker of cardiac hypertrophy in vivo and in vitro. CARP expression was markedly increased in 3 distinct models of cardiac hypertrophy in rats: constriction of abdominal aorta, spontaneously hypertensive rats, and Dahl salt-sensitive rats. In addition, we found that CARP mRNA levels correlate very strongly with the brain natriuretic peptide mRNA levels in Dahl rats. Transient transfection assays into primary cultures of neonatal rat cardiac myocytes indicate that transcription from the CARP and brain natriuretic peptide promoters is stimulated by overexpression of p38 and Rac1, components of the stress-activated mitogen-activated protein kinase pathways. Mutation analysis and electrophoretic mobility shift assays indicated that the M-CAT element can serve as a binding site for nuclear factors, and this element is important for the induction of CARP promoter activity by p38 and Rac1. Thus, our data suggest that M-CAT element is responsible for the regulation of the CARP gene in response to the activation of stress-responsive mitogen-activated protein kinase pathways. Moreover, given that activation of these pathways is associated with cardiac hypertrophy, we propose that CARP represents a novel genetic marker of cardiac hypertrophy.

Topics: Animals; Ankyrin Repeat; Cardiomegaly; Gene Expression Regulation; Male; Mitogen-Activated Protein Kinases; Muscle Proteins; Natriuretic Peptide, Brain; Nuclear Proteins; p38 Mitogen-Activated Protein Kinases; Promoter Regions, Genetic; rac1 GTP-Binding Protein; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Repressor Proteins; RNA, Messenger

We studied the effects of angiotensin II (Ang II) and diastolic overstretch on the induction of cardiac growth in isometrically contracting muscle preparations from human right atria and left ventricles. We used the gene expression of brain natriuretic peptide (BNP) as a molecular marker of cardiac hypertrophy.. Northern blot analysis was performed in human atrial muscle preparations, which were either incubated in 10(-6) mol/L Ang II for 45 minutes or diastolically stretched to 120% of optimum muscle length. Similar experiments were performed with human left ventricular muscle preparations. Results were as follows: (1) BNP gene expression increased in human atrial myocardium 4-fold when stimulated by Ang II (n=7, P<0.001). (2) Diastolic overstretch increased BNP expression in a time-dependent manner. The linear regression equations for the BNP/GAPDH ratio as a function of time (hours) were y=1.21+0.62x (P:<0.001) for overstretched preparations and y=1.07-0.01x (P:=NS) for atrial preparations kept at physiological muscle length. (3) In left ventricular human muscle preparations, diastolic overstretch and Ang II increased BNP gene expression as well. (4) In addition, the Ang II subtype 1 receptor blocker losartan was able to block the effects of Ang II and diastolic overstretch.. Cardiac hypertrophy can be induced in isolated human atrial and left ventricular intact myocardium by Ang II and diastolic overstretch but not by isometric afterload. The fact that the induction of cardiac growth is inhibited by the blockade of Ang II subtype 1 receptors is of scientific and clinical importance.

Topics: Angiotensin II; Blotting, Northern; Cardiomegaly; Diastole; Heart Atria; Heart Ventricles; Humans; In Vitro Techniques; Isometric Contraction; Muscle Fibers, Skeletal; Myocardial Contraction; Myocardium; Natriuretic Peptide, Brain; RNA, Messenger; Stress, Mechanical

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) upregulation are genetic markers for the chronic hypertrophic phenotype but also have important acute physiologic effects on salt and water balance and blood pressure control. The presence of a dual NP-system led us to hypothesize a differential expression of ANP and BNP in response to an acute hemodynamic stress of volume overload in the left ventricle (LV) and right ventricle (RV). Accordingly, we examined the temporal relationship between the RV and LV expression of ANP and BNP mRNA and NP receptor mRNA levels on days 1, 2, 3, and 7 after induction of aortocaval fistula in the rat. LV end-diastolic pressure was increased 1.5-fold by day 3 and 2.0-fold by day 7 compared to control (P<0.05). LV weight increased by day 7 compared to control (2.34+/-0.04 vs 3.07+/-0.10 mg/g, P<0.05) while RV weight did not change over the 7 days. There was a 7-fold increase of ANP mRNA in LV at day 1, which was sustained through day 7, while LV BNP mRNA levels did not differ from controls over the 7 days. In contrast, RV mRNA transcript levels for ANP and BNP were increased >2-fold by day 2 and this increase was sustained throughout 7 days. NP clearance receptor was decreased by 75% by day 7 in the LV but did not change in the RV. Thus, LV ANP mRNA levels increased before the onset of LV hypertrophy and RV BNP mRNA levels increased in the absence of RV hypertrophy. The disparate response of BNP and the NP clearance receptor transcript levels in the LV and RV may be related to differences in load and/or differential expression of the NP system in the LV and RV in response to acute haemodynamic stress.

Topics: Animals; Atrial Natriuretic Factor; Blood Pressure; Body Weight; Cardiomegaly; Gene Expression Regulation; Hemodynamics; Male; Myocardium; Natriuretic Peptide, Brain; Organ Size; Rats; Rats, Sprague-Dawley; Receptors, Atrial Natriuretic Factor; RNA, Messenger; Transcription, Genetic

Higher than normal levels of plasma brain natriuretic peptide (BNP) are often found in elderly patients without overt heart failure.. To investigate the relationships between echocardiographic findings and levels of BNP in inpatients undergoing rehabilitation.. Ejection fraction, early-to-atrial peak transmitral velocity ratio (EAR) and left ventricular mass index were calculated. The patients were 34 men and 83 women, aged 83.4 +/- 0.8 years (mean +/- SEM).. The average BNP was 3.5 times higher than the normal range. Age of and BNP level in patients with mild renal dysfunction were significantly greater than age of and BNP level in those with normal renal function. BNP level in patients with left ventricular hypertrophy (LVH) was higher than that in patients without LVH, and there was a positive correlation between left ventricular mass index and BNP level. However, there was no difference between BNP levels of patients with ejection fraction < 50% and > or = 50% (n = 27 versus 90, ejection fractions 40 versus 64%, BNP levels 22.6 +/- 4.0 versus 17.5 +/- 1.6 pmol/l). Moreover, even elderly inpatients without LVH, without cardiovascular diseases, with sinus rhythm, with normal renal function, and with normal left ventricle systolic function had BNP levels that were greater than normal (n = 21, BNP level 11.0 +/- 1.5 pmol/l). We measured EAR of 76 of 90 patients with normal left ventricle systolic function, and 72 of the 76 patients had EAR < 1.. These results indicate that renal dysfunction and systolic dysfunction as well as cardiac hypertrophy and lower than normal diastolic function contribute to the elevation of BNP levels in elderly inpatients who do not have overt heart failure.

Topics: Aged; Aged, 80 and over; Aging; Cardiomegaly; Diastole; Echocardiography; Female; Humans; Inpatients; Kidney Diseases; Male; Natriuretic Peptide, Brain; Regression Analysis; Systole

Application of mechanical strain to neonatal rat ventricular myocytes in culture evokes changes in gene expression reminiscent of those that occur with hypertrophy in vivo, such as stimulation of brain natriuretic peptide (BNP) gene expression. Here, we show that a major component of strain-dependent BNP promoter activation results from stimulation of p38 mitogen-activated protein kinase (MAPK) in the cardiac myocyte. Strain increased p38 activity in a time-dependent fashion. The p38 inhibitor SB203580 led to a reduction of approximately 60% in strain-activated human BNP (hBNP) promoter activity. Cotransfection of wild-type p38 increased both basal and strain-dependent promoter activity, while cotransfection with MKK6AL, a dominant-negative inhibitor of p38 MAPK kinase, resulted in partial inhibition of either p38- or strain-activated hBNP promoter activity. p38 MAPK increased hBNP promoter activity through activation of the transcription factor NF-kappaB. Activation of the hBNP promoter by either p38 or strain was mediated by DNA elements present in the 5' flanking sequence of the gene. Mechanical strain promoted assembly of NF-kappaB components on these DNA elements in vitro. Thus, induction of the hBNP promoter by mechanical strain depends, at least in part, on stimulation of p38 and subsequent activation of NF-kappaB. This activation may play an important role in signaling the increased BNP gene expression that accompanies hemodynamic overload and cardiac hypertrophy in vivo.

Topics: Animals; Cardiomegaly; Cells, Cultured; DNA-Binding Proteins; Enzyme Activation; Enzyme Inhibitors; Genes, Reporter; Humans; I-kappa B Proteins; Imidazoles; Mitogen-Activated Protein Kinases; Mutation; Myocardium; Natriuretic Peptide, Brain; NF-kappa B; NF-KappaB Inhibitor alpha; p38 Mitogen-Activated Protein Kinases; Promoter Regions, Genetic; Pyridines; Rats; Stress, Mechanical; Transcriptional Activation; Transfection

This study was designed to examine the effects of interleukin-1 beta (IL-1 beta) on myocyte (MC) hypertrophy and the production of A-type natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) in rat ventricular cardiocyte culture, and to investigate the role of nonmyocyte (NMC) in this process. We examined the effects of IL-1 beta on the production of ANP and BNP in comparison with the effects of endothelin-1 (ET-1) by using two types of neonatal rat cardiocyte culture; MC-enriched culture and MC-NMC coculture. In the MC-enriched culture, the increase in secretion of ANP and BNP was small in treatment with IL-1 beta (1000 pg/ml), while ET-1 (10 nM) markedly augmented the secretion of ANP and BNP. In the MC-NMC coculture, IL-1 beta and ET-1 each significantly augmented the secretion of ANP and BNP. The degree of the increase of ANP and BNP was equivalent between IL-1 beta and ET-1. As for the morphological changes of MCs, IL-1 beta induced the star-shaped MC hypertrophy characterized by elongation and pointed edges only in the MC-NMC coculture, while ET-1 induced the MC hypertrophy characterized by shapes of squares, triangles or circles in both cultures. This study shows that IL-1 beta induces unique cardiac hypertrophy and the marked secretion of ANP and BNP, and that NMC is indispensable when treated with IL-1 beta.

Topics: Animals; Animals, Newborn; Atrial Natriuretic Factor; Cardiomegaly; Cells, Cultured; Dose-Response Relationship, Drug; Endothelin-1; Gene Expression Regulation; Heart Ventricles; Interleukin-1; Kinetics; Myocardium; Natriuretic Peptide, Brain; Rats; Rats, Wistar

Glucose enters the heart via GLUT1 and GLUT4 glucose transporters. GLUT4-deficient mice develop striking cardiac hypertrophy and die prematurely. Whether their cardiac changes are caused primarily by GLUT4 deficiency in cardiomyocytes or by metabolic changes resulting from the absence of GLUT4 in skeletal muscle and adipose tissue is unclear. To determine the role of GLUT4 in the heart we used cre-loxP recombination to generate G4H(-/-) mice in which GLUT4 expression is abolished in the heart but is present in skeletal muscle and adipose tissue. Life span and serum concentrations of insulin, glucose, FFAs, lactate, and beta-hydroxybutyrate were normal. Basal cardiac glucose transport and GLUT1 expression were both increased approximately 3-fold in G4H(-/-) mice, but insulin-stimulated glucose uptake was abolished. G4H(-/-) mice develop modest cardiac hypertrophy associated with increased myocyte size and induction of atrial natriuretic and brain natriuretic peptide gene expression in the ventricles. Myocardial fibrosis did not occur. Basal and isoproterenol-stimulated isovolumic contractile performance was preserved. Thus, selective ablation of GLUT4 in the heart initiates a series of events that results in compensated cardiac hypertrophy.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Female; Glucose; Glucose Transporter Type 1; Glucose Transporter Type 4; Male; Mice; Mice, Transgenic; Monosaccharide Transport Proteins; Muscle Proteins; Myocardial Contraction; Myocardium; Natriuretic Peptide, Brain; Organ Size

To study the effects of long-term treatment with the type 1 angiotensin (AT1) receptor antagonist losartan and the angiotensin-converting enzyme (ACE) inhibitor enalapril, on cardiac adrenomedullin (ADM), atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) gene expression.. Spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats were given losartan (15 mg/kg per day) or enalapril (4 mg/kg per day) orally for 10 weeks. The effects of drugs on systolic blood pressure, cardiac hypertrophy, ANP, BNP and ADM mRNA and immunoreactive-ANP (IR)-ANP, IR-BNP and IR-ADM levels in the left ventricle and atria were compared.. Losartan and enalapril treatments completely inhibited the increase of systolic blood pressure occurring with ageing in SHR. The ratio of heart to body weight was reduced in both losartan- and enalapril-treated SHR and WKY rats. Treatment with losartan or enalapril reduced left ventricular ANP mRNA and IR-ANP in both strains, and ventricular BNP mRNA levels in SHR rats. Inhibition of ACE, AT1 receptor antagonism, changes in blood pressure or cardiac mass had no effect on left ventricular ADM gene expression in SHR and WKY rats. In addition, atrial IR-ANP and IR-ADM levels increased in SHR whereas IR-BNP levels decreased in WKY and SHR rats in response to drug treatments.. Our results show that ventricular ADM synthesis is an insensitive marker of changes in haemodynamic load or cardiac hypertrophy. Furthermore, the expression of ADM, ANP and BNP genes is differently regulated both in the left ventricle and atria in response to AT1 receptor antagonism and ACE inhibition.

Topics: Adrenomedullin; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Animals; Atrial Natriuretic Factor; Blood Pressure; Cardiomegaly; Enalapril; Gene Expression; Heart; Hypertension; Losartan; Male; Natriuretic Peptide, Brain; Peptides; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Reference Values

Increasing evidence has suggested that locally produced angiotensin II (Ang II) plays an important role in the development of cardiac hypertrophy through the Ang II type 1 receptor (AT1). We and others have recently reported that Ang II is critical for mechanical stress-induced hypertrophic responses in vitro. Using AT1a knockout (KO) mice, we examined whether Ang II is indispensable for pressure overload-induced cardiac hypertrophy in the present study. Reverse-transcriptase polymerase chain reaction analysis revealed that AT1 mRNA levels were <10% in the heart of KO mice compared with wild-type (WT) mice, but the Ang II type 2 receptor gene was expressed at almost the same levels in the hearts of both mice. Intravenous infusion of subpressor dose of Ang II induced c-fos gene expression in the hearts of WT mice but not KO mice. Acute pressure overload, however, induced expressions of immediate-early response genes and activations of mitogen-activated protein kinases in the hearts of KO mice as well as WT mice. Both basal and activated levels of all these responses were significantly higher in KO mice than in WT mice. Pressure overload markedly increased the heart weight-to-body weight ratio in both mice strains at 14 days after aortic banding. These results suggest that acute hypertrophic responses could be induced by pressure overload in the in vivo heart without AT1 signaling.

Topics: Angiotensin II; Animals; Aorta; Calcium-Calmodulin-Dependent Protein Kinases; Cardiomegaly; Gene Expression; Genes, fos; Genes, jun; Hemodynamics; Infusions, Intravenous; Mice; Mice, Knockout; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Polymerase Chain Reaction; Transcription, Genetic; Ventricular Pressure

In response to numerous pathologic stimuli, the myocardium undergoes a hypertrophic response characterized by increased myocardial cell size and activation of fetal cardiac genes. We show that cardiac hypertrophy is induced by the calcium-dependent phosphatase calcineurin, which dephosphorylates the transcription factor NF-AT3, enabling it to translocate to the nucleus. NF-AT3 interacts with the cardiac zinc finger transcription factor GATA4, resulting in synergistic activation of cardiac transcription. Transgenic mice that express activated forms of calcineurin or NF-AT3 in the heart develop cardiac hypertrophy and heart failure that mimic human heart disease. Pharmacologic inhibition of calcineurin activity blocks hypertrophy in vivo and in vitro. These results define a novel hypertrophic signaling pathway and suggest pharmacologic approaches to prevent cardiac hypertrophy and heart failure.

Topics: Angiotensin II; Animals; Animals, Newborn; Atrial Natriuretic Factor; Calcineurin; Cardiomegaly; Cell Nucleus; DNA-Binding Proteins; GATA4 Transcription Factor; Immunosuppressive Agents; Mice; Mice, Transgenic; Myocardium; Natriuretic Peptide, Brain; NFATC Transcription Factors; Nuclear Proteins; Phenylephrine; Promoter Regions, Genetic; Rats; Recombinant Fusion Proteins; Signal Transduction; Transcription Factors; Transcription, Genetic; Transcriptional Activation; Zinc Fingers

The aim of this study was to investigate the relationships between levels of natriuretic peptides and adrenomedullin and 24 h blood pressure levels in elderly hypertensives.. We performed both 24 h ambulatory blood pressure monitoring and measurement of plasma levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and adrenomedullin in 118 asymptomatic hypertensive elderly (> 60 years old) patients. We classified the subjects into groups with isolated clinic hypertension (n = 40) and sustained hypertension (n = 78). We also measured the levels of these peptides in 37 elderly normotensive subjects.. Plasma ANP and BNP levels were slightly increased in patients with isolated clinic hypertension compared with elderly normotensives. Among the hypertensives, plasma ANP and BNP levels were more closely related to 24 h blood pressure levels than to office blood pressure levels. Sustained hypertensives showed significantly increased plasma levels of ANP and BNP compared with isolated clinic hypertensives, while adrenomedullin levels were similar in the two groups. Elderly hypertensives with left ventricular hypertrophy detected by electrocardiography had significantly higher levels of ANP and BNP, and higher BNP/ANP ratios than those without left ventricular hypertrophy, while there was no significant difference in adrenomedullin levels between the two groups.. Our results suggest that measurements of ANP and BNP may be useful in detecting left ventricular hypertrophy and in differentiating isolated clinic hypertension from sustained hypertension in elderly hypertensive patients.

Topics: Adrenomedullin; Aged; Atrial Natriuretic Factor; Blood Pressure; Cardiomegaly; Circadian Rhythm; Echocardiography; Female; Humans; Hypertension; Male; Middle Aged; Natriuretic Peptide, Brain; Peptides

Chronic pressure overload is known to increase cardiac mass and expression levels of both atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) mRNAs. Although mechanical stretching of cardiac myocytes could cause these changes, humoral factor(s) secondary to pressure overload may also be involved. To dissociate humoral effects from the effects of mechanical loading on cardiac hypertrophic responses, we examined expression of ANP and BNP at both mRNA and protein levels and proportions of myosin isoforms in transplanted cervical hearts that were mechanically unloaded under conditions with or without hypertension by aortic coarctation. Seven days after transplantation, cardiac atrophy that usually occurs in transplanted hearts without hypertension by coarctation was prevented in the transplanted hearts with hypertension by coarctation. The levels of expression of ANP and BNP mRNAs were increased in the transplanted hearts with relative to those without hypertension by coarctation. The plasma level of angiotensin II was higher in rats with than without hypertension by coarctation. Plasma endothelin-1 levels were not significantly different between the two groups. In addition, levels of expression of ANP and BNP mRNAs were increased in the transplanted hearts without hypertension relative to those in the in situ hearts. The proportion of the V3 myosin isoform was also increased in the transplanted hearts without hypertension relative to the in situ hearts. These results indicate that humoral factor(s) secondary to the pressure overload produced by aortic coarctation enhanced the cardiac hypertrophic response and elevated the levels of mRNAs encoding these embryonic markers. Moreover, our findings regarding ANP and BNP expression in the transplanted hearts provide additional evidence that the fetal genes are reexpressed during the process of cardiac atrophy as well as in cardiac hypertrophy.

Topics: Angiotensin II; Animals; Aortic Coarctation; Atrial Natriuretic Factor; Atrophy; Blood Pressure; Body Weight; Cardiomegaly; Endothelin-1; Heart Rate; Heart Transplantation; Hypertension; Male; Myosins; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Rats; Rats, Inbred Lew; RNA, Messenger; Transcription, Genetic; Transplantation, Heterotopic; Transplantation, Isogeneic

When hypertrophic growth is induced in neonatal rat cardiocytes by stretching, the cardiocytes express high levels of brain-type natriuretic peptide (BNP) and the proprotein-processing enzyme furin. A BNP precursor, gammaBNP, possesses a furin-cleavable Arg-X-X-Arg motif, which is cleaved when gammaBNP is processed to form BNP-45. The Arg-X-X-Arg motif is found in many precursors of growth factors and growth-related proteins. To determine if furin converts gammaBNP to BNP-45 as well as other unidentified growth-promoting protein precursors to their active form that may induce hypertrophic growth in cardiocytes, we used two protease inhibitor systems, synthetic peptidyl chloromethyl ketones (CMK) (dec-Arg-Val-Lys-Arg-CMK and dec-Phe-Ala-Lys-Arg-CMK; where dec is decanoyl) and vaccinia vector-integrated native and variant alpha1-antitrypsins. The furin-specific inhibitors, dec-Arg-Val-Lys-Arg-CMK and variant alpha1-antitrypsin with the inhibitory determinant Arg-X-X-Arg, suppressed the stretch-induced hypertrophic growth of cardiocytes as well as the processing of gammaBNP to BNP-45. The other serine protease inhibitors and variant alpha1-antitrypsin against elastase, or thrombin, however, neither suppressed the hypertrophic growth nor prevented the processing of gammaBNP to BNP-45. Thus, we suggest that furin catalyzes the conversion of gammaBNP to BNP-45 as well as growth-promoting proproteins to their active form, which might induce hypertrophic growth in cardiocytes.

Topics: Animals; Cardiomegaly; Cells, Cultured; Furin; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Protein Precursors; Rats; Rats, Wistar; Subtilisins

Left ventricular assist devices (LVAD) provide lifesaving circulatory support to patients awaiting heart transplantation. To date, the extent to which sustained mechanical unloading alters the phenotype of pathologic myocardial hypertrophy in dilated cardiomyopathy is unknown.. We examined left ventricular size, myocyte and myocardial immunoreactivity for atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in eight patients with advanced dilated cardiomyopathy before and after LVAD support. The mean duration of congestive heart failure was 18 +/- 5 months, and LVAD support averaged 42 +/- 4 days before heart transplantation.. Echocardiographically determined left ventricular mass decreased from 505 +/- 83 to 297 +/- 52 gm (p < 0.05) during LVAD support, whereas minimum myocyte diameter decreased from 28.1 +/- 0.9 to 21.7 +/- 0.6 microns (p < 0.01) in transmural myocardial tissue specimens. Overall left ventricular ANP immunopositivity decreased from 48% at LVAD placement to 12% at transplantation (p < 0.05), whereas BNP immunopositivity decreased from 28% to 4% after LVAD support. Moreover, a gradient of ANP and BNP immunostaining from subendocardium to epicardium observed before mechanical unloading diminished after LVAD support. Analysis of the relationship between left ventricular mass and ANP immunopositivity revealed a close and highly significant correlation between these variables.. These studies demonstrate remarkable left ventricular plasticity even in the presence of advanced cardiomyopathy. Parallel reductions in myocardial mass and myocyte size with reductions in ventricular ANP and BNP immunostaining indicate a novel regression of the phenotype of pathologic hypertrophy within the human myocardium after LVAD support.

Topics: Adolescent; Adult; Atrial Natriuretic Factor; Cardiomegaly; Cardiomyopathy, Dilated; Echocardiography, Doppler; Endocardium; Female; Heart; Heart-Assist Devices; Humans; Immunoenzyme Techniques; Male; Middle Aged; Myocardium; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Ventricular Function, Left

In cardiac hypertrophy, both excessive enlargement of cardiac myocytes and progressive interstitial fibrosis are well known to occur simultaneously. In the present study, to investigate the interaction between ventricular myocytes (MCs) and cardiac nonmyocytes (NMCs), mostly fibroblasts, during cardiocytes hypertrophy, we examined the change in cell size and gene expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in cultured MCs as markers for hypertrophy in the neonatal rat ventricular cardiac cell culture system.. The size of cultured MCs significantly increased in the MC-NMC coculture. Concomitantly, secretions of ANP and BNP into culture media were significantly increased in the MC-NMC coculture compared with in the MC culture (with the possible contamination of NMC <1% of MC). Moreover, in the MC culture, enlargement of MC and an increase in ANP and BNP secretions were induced by treatment with conditioned media of the NMC culture. A considerable amount of endothelin (ET)-1 production was detected in the NMC-conditioned media. BQ-123, an ET-A receptor antagonist, and bosentan, a nonselective ET receptor antagonist, significantly blocked the hypertrophic response of MCs induced by treatment with NMC-conditioned media. Angiotensin II (Ang II) (10(-10) to 10(-6) mol/L) and transforming growth factor-beta1 (TGF-beta1) (10(-13) to 10(-9) mol/L), both of which are known to be cardiac hypertrophic factors, did not induce hypertrophy in MC culture, but both Ang II and TGF-beta1 increased the size of MCs and augmented ANP and BNP productions in the MC-NMC coculture. This hypertrophic activity of Ang II and TGF-beta1 was associated with the potentiation of ET-1 production in the MC-NMC coculture, and the effect of Ang II or TGF-beta1 on the secretions of ANP and BNP in the coculture was significantly suppressed by pretreatment with BQ-123.. These results demonstrate that NMCs regulate MC hypertrophy at least partially via ET-1 secretion and that the interaction between MCs and NMCs plays a critical role during the process of Ang II- or TGF-beta1-induced cardiocyte hypertrophy.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Cardiomegaly; Cattle; Coculture Techniques; Culture Media, Conditioned; Endothelin Receptor Antagonists; Endothelin-1; Hypertrophy; Lipoproteins, LDL; Myocardium; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Paracrine Communication; Rats; Rats, Wistar; Receptors, Angiotensin; Receptors, Endothelin; RNA, Messenger; Transforming Growth Factor beta; Ventricular Function

In cardiac hypertrophy or ventricular remodeling, not only the enlargement of myocytes but also interstitial or perivascular fibrosis are observed simultaneously, which suggests an interaction between cardiac myocytes and fibroblasts. In this study, we examined the mechanism of cyclic mechanical stretch-induced myocyte hypertrophy, highlighting the interaction between myocytes and cardiac nonmyocytes, mostly fibroblasts. Ventricular myocytes (MC) and cardiac nonmyocytes (NMC) were separately extracted from neonatal rat ventricles by the discontinuous Percoll gradient method and primary cultures of cardiac cells were prepared. Cyclic mechanical stretch was applied to the cultures with a Flexercell Stress Unit. In addition to cell size, we examined atrial natriuretic peptide/brain natriuretic peptide (ANP/BNP) production as the most sensitive biological markers for MC hypertrophy. Cyclic stretch did not induce hypertrophic responses in MC when they were cultured without NMC. In contrast, when MC were co-cultured with NMC, cyclic stretch induced further increase in ANP/BNP production (2.2-fold and 2.1-fold increases versus non-stretch group, after 48-h incubation). This increase in ANP/BNP production in the co-culture was significantly suppressed by CV-11974, an angiotensin II type 1 receptor antagonist. Moreover, ANP/BNP production in the co-culture was significantly suppressed by BQ-123, an endothelin A receptor antagonist, whether cyclic stretch was applied or not. This study raised the possibility that NMC mediate the hypertrophic effect of mechanical stress on MC by increasing endothelin production. It was also suggested that, in this process, angiotensin II is involved in the crosstalk between MC and NMC.

Topics: Angiotensin Receptor Antagonists; Animals; Atrial Natriuretic Factor; Benzimidazoles; Biphenyl Compounds; Cardiomegaly; Cells, Cultured; Coculture Techniques; Endothelin Receptor Antagonists; Fibroblasts; Myocardium; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Peptides, Cyclic; Rats; Stress, Mechanical; Tetrazoles

Whereas numerous studies have examined the cardiac tissue content and secretion of atrial natriuretic peptide (ANP), the response of brain natriuretic peptide (BNP) in states of experimental cardiac overload is less well documented. Our recent partial cloning of the ovine BNP gene has enabled us to study changes in cardiac tissue concentration, together with tissue and circulating molecular forms of ANP and BNP, in response to cardiac overload induced by rapid ventricular pacing (n = 7) and aortic coarctation (n = 6). In normal sheep, although highest levels of BNP were found in atrial tissue (15-fold those of the ventricle), the BNP/ANP concentration ratio in the ventricles was 10- to 20-fold higher than the ratio calculated for atrial tissue. Compared with normal sheep, significant depletion of both ANP and BNP concentrations within the left ventricle occurred after rapid ventricular pacing. Size exclusion and reverse phase HPLC analysis of atrial and ventricular tissue extracts from normal and overloaded sheep showed a single peak of high molecular weight BNP consistent with the proBNP hormone. In contrast, immunoreactive BNP extracted from plasma drawn from the coronary sinus was all low molecular weight material. Further analysis of plasma BNP using ion exchange HPLC disclosed at least 3 distinct immunoreactive peaks consistent with ovine BNP forms 26-29 amino acid residues in length. These findings show that BNP is stored as the prohormone in sheep cardiac tissues and that complete processing to mature forms occurs at the time of secretion. The capacity to process the prohormone at secretion is not impaired by chronic heart failure.

Topics: Animals; Atrial Natriuretic Factor; Cardiac Pacing, Artificial; Cardiomegaly; Chromatography, High Pressure Liquid; Disease Models, Animal; Heart Failure; Molecular Weight; Myocardium; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Radioimmunoassay; Sheep

1,25(OH)2 Vitamin D3 (VD3) and retinoic acid (RA) function as ligands for nuclear receptors which regulate transcription. Though the cardiovascular system is not thought to represent a classical target for these ligands, it is clear that both cardiac myocytes and vascular smooth muscle cells respond to these agents with changes in growth characteristics and gene expression. In this study we demonstrate that each of these ligands suppresses many of the phenotypic correlates of endothelin-induced hypertrophy in a cultured neonatal rat cardiac ventriculocyte model. Each of these agents reduced endothelin-stimulated ANP secretion in a dose-dependent fashion and the two in combination proved to be more effective than either agent used alone (VD3: 49%; RA:52%; VD3 + RA:80% inhibition). RA, at concentrations known to activate the retinoid X receptor, and, to a lesser extent, VD3 effected a reduction in atrial natriuretic peptide, brain natriuretic peptide, and alpha-skeletal actin mRNA levels. Similar inhibition (VD3:30%; RA:33%; VD3 + RA:59% inhibition) was demonstrated when cells transfected with reporter constructs harboring the relevant promoter sequences were treated with VD3 and/or RA for 48 h. These effects were not accompanied by alterations in endothelin-induced c-fos, c-jun, or c-myc gene expression, suggesting either that the inhibitory locus responsible for the reduction in the mRNA levels lies distal to the activation of the immediate early gene response or that the two are not mechanistically coupled. Both VD3 and RA also reduced [3H]leucine incorporation (VD3:30%; RA:33%; VD3 + RA:45% inhibition) in endothelin-stimulated ventriculocytes and, once again, the combination of the two was more effective than either agent used in isolation. Finally, 1,25(OH)2 vitamin D3 abrogated the increase in cell size seen after endothelin treatment. These findings suggest that the liganded vitamin D and retinoid receptors are capable of modulating the hypertrophic process in vitro and that agents acting through these or similar signaling pathways may be of value in probing the molecular mechanisms underlying hypertrophy.

Topics: Animals; Animals, Newborn; Atrial Natriuretic Factor; Base Sequence; Calcitriol; Cardiomegaly; Chloramphenicol O-Acetyltransferase; DNA Primers; Endothelins; Gene Expression; Genes, Reporter; Heart; Humans; In Vitro Techniques; Molecular Sequence Data; Myocardium; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Rats; Receptors, Retinoic Acid; Retinoid X Receptors; Transcription Factors; Transfection; Tretinoin

1. We assessed the changes of atrial natriuretic peptide and brain natriuretic peptide gene expression associated with progression and regression of cardiac hypertrophy in renovascular hypertensive rats (RHR). 2. Two-kidney, one-clip hypertensive rats (6-week-old male Wistar) were made and studied 6 (RHR-1) and 10 weeks (RHR-2) after the procedure. Regression of cardiac hypertrophy was induced by nephrectomy at 6 weeks after constriction, and the nephrectomized rats were maintained further for 4 weeks (nephrectomized rat: NEP). Sham operation was performed, and the rats were studied after 6 (Sham-1) and 10 weeks (Sham-2). Atrial natriuretic peptide and brain natriuretic peptide gene expression in the left ventricle was analysed by Northern blotting. 3. Plasma atrial natriuretic peptide and brain natriuretic peptide were significantly higher in RHR-1 and RHR-2 than in Sham-1, Sham-2 and NEP. Atrial natriuretic peptide and brain natriuretic peptide mRNA levels in RHR-1 were approximately 7.2-fold and 1.8-fold higher than those in Sham-1, respectively, and the corresponding levels in RHR-2 were 13.0-fold and 2.4-fold higher than those in Sham-2, respectively. Atrial natriuretic peptide and brain natriuretic peptide mRNA levels of NEP were normalized. Levels of atrial natriuretic peptide and brain natriuretic peptide mRNA were well correlated positively with left ventricular weight/body weight ratios. There was a significant positive correlation between the levels of atrial natriuretic peptide and brain natriuretic peptide mRNA (r = 0.86, P < 0.01). 4. We conclude that the expression of atrial natriuretic peptide and brain natriuretic peptide genes is regulated in accordance with the degree of myocardial hypertrophy and that the augmented expression of these two natriuretic peptides may play an important role in the maintenance of cardiovascular haemodynamics in renovascular hypertension.

Topics: Animals; Atrial Natriuretic Factor; Base Sequence; Blotting, Northern; Cardiomegaly; DNA Primers; Gene Expression Regulation; Hypertension, Renal; Male; Molecular Sequence Data; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Rats; Rats, Inbred SHR; Rats, Wistar; RNA, Messenger

We examined the relationship between cardiac hypertrophy, myosin heavy chain (MHC) isoform expression, and production of atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP) before and after the development of DOCA-salt hypertension. DOCA-salt rats exhibited significant left ventricular hypertrophy at the prehypertensive stage (1 week of treatment), without MHC isoform switch or change in natriuretic peptide gene expression. In the hypertensive stage (5 weeks of treatment), pronounced left ventricular hypertrophy was observed, and this was characterized by an increase in beta-MHC protein, resulting in a switch from 90% alpha-MHC to 51% alpha-MHC and 49% beta-MHC. ANF and BNP mRNA levels and peptide content were significantly increased at this stage. Unexpectedly, the MHC isoform switch was evident in the non-hypertrophied right ventricle to the same degree as in the left ventricle. Natriuretic peptide production was also increased in the right ventricle at 5 weeks of treatment, but to a lesser degree than in the left ventricle. In contrast, in the hypertrophied left atrium there was no MHC isoform switch, while ANF and BNP mRNA levels were augmented. Plasma ANF was significantly increased in the prehypertensive stage; this was accompanied by a partial depletion of atrial ANF stores. Plasma BNP was increased only in the hypertensive stage, reflecting an increase in ventricular BNP synthesis and secretion. These results suggest that 1) cardiac hypertrophy, MHC isoform expression, and stimulation of natriuretic peptide production are processes that may be dissociated from each other; 2) increases in plasma ANF without a concomitant increase in plasma BNP reflect atrial hemodynamic overload, while increases in both ANF and BNP in plasma are associated with ventricular hypertrophy; and 3) there exist differences in the storage, secretion, and processing patterns of ANF and BNP in the atria.

Topics: Animals; Atrial Natriuretic Factor; Blood Pressure; Blotting, Northern; Body Weight; Cardiomegaly; Centrifugation, Density Gradient; Chromatography, High Pressure Liquid; Desoxycorticosterone; Hypertension; Isomerism; Male; Myocardium; Myosin Subfragments; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Organ Size; Radioimmunoassay; Rats; Rats, Sprague-Dawley; RNA; Sodium Chloride

The aim was to compare activities of the type A and type B natriuretic factor genes during development of cardiac hypertrophy by use of a non-radioactive method designed for assessment of stable atrial and brain natriuretic factor (ANF, BNF) transcript levels in biopsy sized tissue samples.. At 1 and 7 days after aortocaval shunt or sham surgery in rats, quantitative reverse transcriptase mediated polymerase chain reaction (Q-RT-PCR) was used to determine mRNA levels in cardiac tissues. Phosphoglycerate kinase-1 (PGK-1) mRNA levels served as an external standard for Q-RT-CR.. The shunt increased left ventricular end diastolic pressure at days 1 and 7, and cardiac weight was increased by day 7. By day 1, left ventricular BNF mRNA levels were twice those of controls, whereas ANF mRNA levels were not changed. By day 7, left ventricular BNF mRNA levels were increased 15-fold, and those for ANF were increased fivefold; the BNF mRNAs were also increased in right atria and right ventricle, about fivefold in both cases.. Both natriuretic factor genes were activated by cardiac volume overload, and the increase in the level of left ventricular BNF transcripts-observed for the first time-was in fact more rapid and exceeded that of ANF. The Q-RT-PCR assay will be of value to investigate the response to increased work load of cardiac muscle in vivo.

Topics: Animals; Atrial Natriuretic Factor; Base Sequence; Cardiomegaly; DNA Primers; Gene Expression Regulation; Male; Molecular Sequence Data; Myocardium; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Polymerase Chain Reaction; Rats; Rats, Wistar

We previously demonstrated that brain natriuretic peptide (BNP) is a cardiac hormone mainly produced in the ventricle, while the major production site of atrial natriuretic peptide (ANP) is the atrium. To assess the pathophysiological role of BNP in ventricular overload, we have examined the gene expression of BNP, In comparison with that of ANP, in a model of cardiac hypertrophy using cultured neonatal rat ventricular cardiocytes. During cardiocyte hypertrophy evoked by endothelin-1, Phenylephrine, or PMA, the steady state level of BNP mRNA increased as rapidly as the "immediate-early" induction of the c-fos gene expression, and reached a maximal level within 1 h. Actinomycin D, a transcriptional inhibitor, completely diminished the response, while the translational blocked with cycloheximide did not inhibit it. In contrast, ANP mRNA began to increase 3 h after the stimulation, and accumulated during cardiocyte hypertrophy. The BNP secretion from ventricular cardiocytes was also stimulated, more rapidly than the ANP secretion. Furthermore, the turnover of BNP mRNA was significantly faster than that of ANP mRNA, being consistent with the existence of AUUUA motif in the 3'-untranslated region of BNP mRNA. These results demonstrate that the gene expression of BNP is distinctly regulated from that of ANP at transcriptional and posttranscriptional levels, and indicate that the characteristics of the BNP gene expression are suitable for its possible role as an " emergency" cardiac hormone against ventricular overload.

Topics: Animals; Animals, Newborn; Atrial Natriuretic Factor; Base Sequence; Cardiomegaly; Cells, Cultured; Chromatography, Gel; Chromatography, High Pressure Liquid; DNA Primers; Endothelins; Enzyme Activation; Gene Expression Regulation; Heart Ventricles; Kinetics; Molecular Sequence Data; Myocardium; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Phenylephrine; Protein Kinase C; Radioimmunoassay; Rats; Rats, Wistar; Restriction Mapping; RNA, Messenger; Tetradecanoylphorbol Acetate; Transcription, Genetic

1. We previously demonstrated that brain natriuretic peptide (BNP) is a cardiac hormone mainly produced in the ventricle, while the major production site of atrial natriuretic peptide (ANP) is the atrium. The production and secretion of BNP and ANP in the hypertrophied ventricles were markedly augmented, serving as a compensation mechanism against ventricular overload by their natriuretic, diuretic and vasodilatory actions. 2. In the present study, we prepared an in vitro model of cardiocyte hypertrophy using cultured neonatal rat ventricular cardiocytes and alpha1-adrenergic stimulation, and examined the gene expressions of BNP and ANP during the process of cardiocyte hypertrophy. 3. The treatment of cultured ventricular cardiocytes with phenylephrine evoked cardiocyte hypertrophy around 24 h after the treatment, which was characterized by augmented expression of the myosin light chain-2 gene and increase in cell size. 4. In this model of cardiocyte hypertrophy, the steady-state level of BNP mRNA rapidly increased to the maximal level within 1 h after the treatment. In contrast, ANP mRNA began to increase at 3 h, and accumulated during the course of cardiocyte hypertrophy. The secretion of BNP from ventricular cardiocytes was also stimulated more rapidly than the ANP secretion. 5. These results indicate that the gene expression of BNP is distinctly regulated from that of ANP in cardiocyte hypertrophy, and suggest a discrete pathophysiological role of BNP as an 'emergency' cardiac hormone against ventricular overload.

Topics: Adrenergic alpha-1 Receptor Agonists; Adrenergic alpha-Agonists; Animals; Animals, Newborn; Atrial Natriuretic Factor; Blotting, Northern; Cardiomegaly; Cells, Cultured; Gene Expression Regulation; Heart Ventricles; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Rats; Rats, Wistar

The blood pressure was decreased after chronic treatment with enalapril, MK-954, and hydralazine in deoxycorticosterone acetate (DOCA)-salt-induced malignant hypertension of spontaneously hypertensive rats (SHR); however, ventricular weight and plasma brain natriuretic peptide (BNP) concentration were decreased after enalapril and MK-954 but not after hydralazine. The BNP secretory rates from the ventricle in enalapril- and MK-954-treated DOCA-salt SHR were decreased to approximately 50% of those in untreated DOCA-salt SHR. The BNP secretory rate from the ventricle was positively correlated with ventricular weight in untreated and treated DOCA-salt SHR. In contrast, acute administration of captopril or MK-954 did not decrease the BNP secretory rate from the heart. Results suggest that the decrease in plasma BNP after enalapril and MK-954 is attributed to a decline in the secretion from the ventricle but not from the atrium. The reduction in ventricular mass appeared to be related to this decline.

Topics: Animals; Atrial Natriuretic Factor; Biphenyl Compounds; Blood Pressure; Blood Urea Nitrogen; Cardiomegaly; Chromatography, High Pressure Liquid; Creatinine; Desoxycorticosterone; Enalapril; Heart; Hydralazine; Hypertension, Malignant; Imidazoles; Losartan; Male; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Rats; Rats, Inbred SHR; Sodium, Dietary; Tetrazoles

We have compared the expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) genes in various human tissues using a quantitative polymerase chain reaction technique. Tissues of three human subjects, obtained at autopsy, were analyzed. BNP transcripts could be detected in the central nervous system, lung, thyroid, adrenal, kidney, spleen, small intestine, ovary, uterus, and striated muscle. ANP transcripts could also be demonstrated in various human extracardiac tissues including several endocrine organs. In all peripheral tissues, the level of both natriuretic peptide transcripts was approximately 1-2 orders of magnitude lower than in cardiac ventricular tissues. This distribution is in marked contrast to the much lower level of ANP and BNP transcripts present in extracardiac rat tissues (generally less than 1/1000 of ventricles). These data suggest differential expression of the two natriuretic peptide genes in cardiac and extracardiac tissues in man. Furthermore, the presence of local synthesis of ANP and BNP in various peripheral organs suggests paracrine and/or autocrine function of these natriuretic peptides.

Topics: Animals; Atrial Natriuretic Factor; Base Sequence; Brain; Cardiomegaly; DNA Primers; Female; Gene Expression; Humans; Liver; Lung; Male; Middle Aged; Molecular Sequence Data; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Organ Specificity; Ovarian Neoplasms; Ovary; Pancreas; Pituitary Gland; Polymerase Chain Reaction; Rats; Transcription, Genetic

A natriuretic peptide, brain natriuretic peptide (BNP), has been isolated from porcine hearts. We performed this study to determine if BNP is secreted from the heart and to identify changes, if any, in the plasma BNP concentration in essential hypertension.. We measured the immunoreactive (ir) BNP concentration at intracardiac sites including the coronary sinus of five patients with heart disease during cardiac catheterization. We examined plasma ir-BNP in 48 hypertensive patients, 15 borderline hypertensive patients, and 25 normotensive subjects.. Plasma ir-BNP in the coronary sinus was greater than at other cardiac sites. The concentration was significantly higher in hypertensive subjects than in borderline hypertensive or normotensive subjects. Hypertensive patients with left ventricular hypertrophy (LVH) established by echocardiography had higher plasma ir-BNP levels than those without LVH. In the hypertensive group, plasma ir-BNP was closely correlated with the LV mass index. In these patients, BNP levels were correlated with mean arterial pressure and inversely correlated with the LV ejection fraction, although these correlations were weak. Reverse-phase high-pressure liquid chromatography showed that the major component of circulating ir-BNP in the hypertensive and normotensive subjects corresponded to authentic human BNP-32.. Human BNP-32 was secreted through the coronary sinus from the heart and may act as a cardiac hormone. Plasma BNP was increased in many of the hypertensive subjects with LVH. The increase in BNP seemed to be related to LVH or the cardiac overload associated with LVH.

Topics: Adult; Cardiac Catheterization; Cardiomegaly; Chromatography, High Pressure Liquid; Clinical Protocols; Female; Humans; Hypertension; Male; Middle Aged; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Radioimmunoassay