natriuretic-peptide--brain and Disease-Models--Animal

Magnesium isoglycyrrhizinate (MgIG) is a magnesium salt of the 18-α glycyrrhizic acid stereoisomer that has exhibited hepato-protective effects and has anti-inflammatory, antioxidant, and antiviral activities. Here, we have investigated the effects and potential mechanisms of action of MgIG, with respect to myocardial fibrosis induced by isoproterenol (ISO) in mice. Mice were administered MgIG for 14days, with concurrent ISO dosing, and were sacrificed two weeks later. Lactate dehydrogenase (LDH) and creatine kinase (CK) concentrations were measured in the blood. Pathological changes in the myocardium were observed via light microscopy. In addition, the expression of the Bax and Bcl-2 genes, and the basic fibroblast growth factor (bFGF) protein were measured via an immunohistochemical method. The RNA expression of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), c-fos, and c-jun mRNA were quantified by reverse transcription-polymerase chain reaction (RT-PCR) in the myocardial tissue. The protein expression of toll-like receptor (TLR) 4, and nuclear factor kappa B (NF-κB) (p65) were measured using Western blot assays. Compared with the control group, the ISO group showed significant increases in bFGF, Bax, Bcl-2, TLR4, and NF-κB (p65) expressions, as well as increased serum levels of LDH and CK. MgIG had a protective effect on ISO-induced myocardial fibrosis, which might be ascribed, at least in part, to the inhibition of the TLR4/NF-κB (p65) signaling pathway.

Topics: Animals; Anti-Inflammatory Agents; Atrial Natriuretic Factor; bcl-2-Associated X Protein; Creatine Kinase; Disease Models, Animal; Fibroblast Growth Factor 2; Fibrosis; Heart Diseases; Humans; Hypertrophy; Isoproterenol; L-Lactate Dehydrogenase; Mice; Mice, Inbred Strains; Myocardium; Natriuretic Peptide, Brain; NF-kappa B; Proto-Oncogene Proteins c-bcl-2; Saponins; Toll-Like Receptor 4; Triterpenes

In an acute care setting, diuretics are often prescribed to maintain or increase urine output in patients presenting with acute kidney injury (AKI). The rationale behind giving diuretics is that they may protect the kidney from ischemic injury by maintaining a nonoliguric state. There have been many studies both supporting and criticizing diuretic use in AKI for improving overall patient outcomes.. A systematic review of the literature was conducted to evaluate the role of diuretics including osmotics, loop diuretics, and nesiritide in modifying AKI.. There was no evidence to suggest that the use of loop diuretics in AKI reduces mortality, the need for dialysis, the number of dialysis sessions, or length of Intensive Care Unit/hospital stay or that it increases the recovery of renal function. There is no benefit for the use of mannitol as an osmotic diuretic over hydration in rhabdomyolysis. In contrast, mannitol was found to cause more harm and to induce nephropathy. Nesiritide did not improve renal function in patients with decompensated heart failure and mild chronic renal insufficiency. Nesiritide may be effective in the prevention of AKI when applied in lower doses for a prolonged period of time in patients with mild to moderate renal insufficiency.. Diuretics have been shown to be ineffective in the prevention of AKI or for improving outcomes once AKI occurs. At best, diuretics can help decrease symptoms of pulmonary edema secondary to volume overload.

Topics: Acute Kidney Injury; Animals; Cohort Studies; Combined Modality Therapy; Contraindications; Critical Care; Disease Models, Animal; Diuretics; Diuretics, Osmotic; Dopamine; Fluid Therapy; Furosemide; Humans; Length of Stay; Mannitol; Meta-Analysis as Topic; Natriuretic Peptide, Brain; Pulmonary Edema; Randomized Controlled Trials as Topic; Renal Dialysis; Rhabdomyolysis; Sodium Potassium Chloride Symporter Inhibitors; Treatment Outcome

Topics: Adrenomedullin; Animals; Aspartic Acid Endopeptidases; Atrial Natriuretic Factor; Disease Models, Animal; Endothelin-Converting Enzymes; Endothelins; Heart Failure; Intracellular Signaling Peptides and Proteins; Metalloendopeptidases; Natriuretic Peptide, Brain; Nitric Oxide; Oxidative Stress; Peptides; Protein Serine-Threonine Kinases; Rats; Rats, Inbred Dahl; Renin-Angiotensin System; rho-Associated Kinases

Topics: Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Atrial Natriuretic Factor; Biomarkers; Calcium Channel Blockers; Cardiomyopathy, Hypertrophic; Disease Models, Animal; Humans; Natriuretic Peptide, Brain

Evidence suggests that adrenomedullin (AM) plays a role in the pathophysiology of heart failure. Circulating concentrations of AM are elevated in cardiovascular disease in proportion to the severity of cardiac and hemodynamic impairment. Raised plasma AM levels following acute cardiac injury and in heart failure provide prognostic information on adverse outcomes. In heart failure, elevated circulating AM also identifies patients likely to receive long-term benefit from inclusion of additional anti-failure therapy (carvedilol). Administration of AM in experimental and human heart failure induces reductions in arterial pressure and cardiac filling pressures, and improves cardiac output, in association with inhibition of plasma aldosterone (despite increased renin release) and sustained (or augmented) renal glomerular filtration and sodium excretion. Furthermore, AM in combination with other therapies (angiotensin-converting enzyme inhibition and augmentation of the natriuretic peptides) results in hemodynamic and renal benefits greater than those achieved by the agents separately. Manipulation of the AM system holds promise as a therapeutic strategy in cardiac disease.

Topics: Adrenomedullin; Amino Acid Sequence; Angiotensin-Converting Enzyme Inhibitors; Animals; Disease Models, Animal; Heart Failure; Humans; Molecular Sequence Data; Natriuretic Peptide, Brain; Peptides; Sequence Alignment; Sheep

The discovery of the natriuretic peptide family was a breakthrough in modern cardiovascular physiology as it provided a direct link between the heart and the kidneys in the regulation of natriuresis. Along with vasopressin and the renin-angiotensin-aldosterone system, the natriuretic peptides comprise the key peptides on which our present understanding of neuroendocrine regulation of the cardiovascular system is based. Three natriuretic peptides have been identified; the A-type, B-type and C-type natriuretic peptides. The former two, the A- and B-type natriuretic peptides, function mainly in the cardiovascular system and comprise the cardiac natriuretic peptides. Together with our increased understanding of the neurohormonal regulation of the cardiovascular system in recent years, the discovery of the natriuretic peptide family was important in the establishment of the new field of cardiovascular endocrinology.

Topics: Animals; Atrial Natriuretic Factor; Cardiovascular Physiological Phenomena; Disease Models, Animal; Humans; Natriuresis; Natriuretic Peptide, Brain; Natriuretic Peptide, C-Type; Peptides

A previous report by our team showed that Waon therapy, using a far infrared-ray dry sauna at 60°C, improves cardiac and vascular function in patients with chronic heart failure (CHF). The purpose of the present study was to clarify the effect of Waon therapy on oxidative stress in CHF patients and investigate its mechanism by animal experiments.. Forty patients with CHF were divided into control (n=20) and Waon therapy (n=20) groups. All patients received standard optimal medications for CHF. Waon therapy group was treated with Waon therapy daily for 4 weeks. After 4 weeks of Waon therapy, concentrations of hydroperoxide and brain natriuretic peptide (BNP) decreased significantly (hydroperoxide, 422±116 to 327±88U.CARR, P<0.001; BNP, 402±221 to 225±137pg/ml, P<0.001), and the nitric oxide metabolites increased (71.2±35.4 to 92.0±40.5mmol/L, P<0.05). In contrast, none of these variables changed over the 4-week interval in the control group. Furthermore, animal experiments were performed using TO-2 cardiomyopathic hamsters. On immunohistochemistry, cardiac expression of 4-hydroxy-2-nonenal, a marker of oxidative stress, was decreased in the 4-week Waon therapy compared to untreated hamsters. On Western blotting, cardiac expressions of heat shock protein (HSP) 27, manganese superoxide dismutase and HSP32, which reduce oxidative stress, were significantly upregulated in the 4-week Waon therapy compared to untreated hamsters.. Waon therapy decreases oxidative stress in patients and hamsters with heart failure.

Topics: Aged; Aldehydes; Animals; Biomarkers; Cardiomyopathy, Dilated; Cardiovascular Agents; Combined Modality Therapy; Cricetinae; Disease Models, Animal; Female; Gene Expression Regulation; Heart Failure; Heat-Shock Proteins; Hot Temperature; Humans; Hydrogen Peroxide; Infrared Rays; Male; Mesocricetus; Middle Aged; Natriuretic Peptide, Brain; Nitric Oxide; Oxidative Stress; Superoxide Dismutase

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

Patients with valvular heart disease require cardiopulmonary bypass and cardiac arrest. Here, we test the hypothesis that exosomal hemoglobin formed during cardiopulmonary bypass mediates acute cardiac injury in humans and in an animal model system.. Plasma exosomes were collected from arterial blood at baseline and 30 minutes after aortic cross-clamp release in 20 patients with primary mitral regurgitation and 7 with aortic stenosis. These exosomes were injected into Sprague-Dawley rats and studied at multiple times up to 30 days. Tissue was examined by hematoxylin and eosin stain, immunohistochemistry, transmission electron microscopy, and brain natriuretic peptide.. Troponin I levels increased from 36 ± 88 ng/L to 3622 ± 3054 ng/L and correlated with exosome hemoglobin content (Spearman r = 0.7136, < .0001, n = 24). Injection of exosomes isolated 30 minutes after cross-clamp release into Sprague-Dawley rats resulted in cardiomyocyte myofibrillar loss at 3 days. Transmission electron microscopy demonstrated accumulation of electron dense particles of ferritin within cardiomyocytes, in the interstitial space, and within exosomes. At 21 days after injection, there was myofibrillar and myosin breakdown, interstitial fibrosis, elevated brain natriuretic peptide, and left ventricle diastolic dysfunction measured by echocardiography/Doppler. Pericardial fluid exosomal hemoglobin content is fourfold higher than simultaneous plasma exosome hemoglobin, suggesting a cardiac source of exosomal hemoglobin.. Red blood cell and cardiac-derived exosomal hemoglobin may be involved in myocardial injury during cardiopulmonary bypass in patients with valvular heart disease.

Topics: Animals; Disease Models, Animal; Exosomes; Heart Injuries; Heart Valve Diseases; Humans; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley

Myocardial remodeling is a complex pathological process and its mechanism is unclear. The present study investigated whether epigallocatechin gallate (EGCG) prevents myocardial remodeling by regulating histone acetylation and explored the mechanisms underlying this effect in the heart of a mouse model of transverse aortic constriction (TAC). A TAC mouse model was created by partial thoracic aortic banding (TAB). Subsequently, TAC mice were injected with EGCG at a dose of 50 mg/kg/day for 12 weeks. The hearts of mice were collected for analysis 4, 8 and 12 weeks after TAC. Histopathological changes in the heart were observed by hematoxylin and eosin, Masson trichrome and wheat germ agglutinin staining. Protein expression levels were investigated using western blotting. Cardiac function of mice was detected by echocardiography. The level of histone acetylated lysine 27 on histone H3 (H3K27ac) first increased and then decreased in the hearts of mice at 4, 8 and 12 weeks after TAC. The expression levels of two genes associated with pathological myocardial remodeling, atrial natriuretic peptide (

Topics: Acetylation; Animals; Atrial Natriuretic Factor; Atrial Remodeling; Catechin; Constriction; Disease Models, Animal; Electrocardiography; Heart Failure; Histone Deacetylases; Histones; Lysine; Male; MEF2 Transcription Factors; Natriuretic Peptide, Brain; Survival Rate; Ventricular Remodeling

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

Left-ventricular hypertrophy, characterized by cardiomyocyte hypertrophy, interstitial cell proliferation, and immune cell infiltration, is a high risk factor for heart failure and death. Chemokines interacting with G protein-coupled chemokine receptors probably play a role in left-ventricular hypertrophy development by promoting recruitment of activated leukocytes and modulating left-ventricular remodeling. Using the minimally invasive model of transverse aortic constriction in mice, we demonstrated that a variety of chemokine and chemokine receptor messenger Ribonucleic Acid are overexpressed in the early and late phase of hypertrophy progression. Among the chemokine receptors, Cx3cr1 and Ccr2 were most strongly overexpressed and were significantly upregulated at 3, 7, and 14 days after transverse aortic constriction. Ligands of CX3CR1 (Cx3cl1) and CCR2 (Ccl2, Ccl7, Ccl12) were significantly overexpressed in the left ventricle at the early stages after mechanical pressure overload. Pharmacological inhibition of CX3CR1 signaling using the antagonist AZD8797 led to a significant reduction of hypertrophy, whereas inhibition of CCR2 with the RS504393 antagonist did not show any effect. Furthermore, AZD8797 treatment reduced the expression of the hypertrophic marker genes Nppa and Nppb as well as the profibrotic genes Tgfb1 and Col1a1 at 14 days after transverse aortic constriction. These findings strongly suggest the involvement of the CX3CR1/CX3CL1 pathway in the pathogenesis of left-ventricular hypertrophy.

Topics: Animals; Aorta; Atrial Natriuretic Factor; Chemokine CX3CL1; Collagen Type I, alpha 1 Chain; Constriction; CX3C Chemokine Receptor 1; Disease Models, Animal; Fibrosis; Hypertrophy, Left Ventricular; Male; Mice, Inbred C57BL; Myocytes, Cardiac; Natriuretic Peptide, Brain; Pyrimidines; Signal Transduction; Thiazoles; Time Factors; Transforming Growth Factor beta1; Ventricular Function, Left; Ventricular Remodeling

Management of acute decompensated heart failure (ADHF) requires disparate treatments depending on the state of systemic/peripheral perfusion and the presence/absence of expanded body-fluid volumes. There is an unmet need for therapeutics that differentially treat each aspect. Atrial natriuretic peptide (ANP) plays an important role in blood pressure and volume regulation. We investigate for the first time the integrated haemodynamic, endocrine and renal effects of human ANP analogues, modified for exclusive vasodilatory (ANP-DRD) or diuretic (ANP-DGD) activities, in normal health and experimental ADHF.. We compared the effects of incremental infusions of ANP analogues ANP-DRD and ANP-DGD with native ANP, in normal (n = 8) and ADHF (n = 8) sheep. ANP-DRD administration increased plasma cyclic guanosine monophosphate (cGMP) in association with dose-dependent reductions in arterial pressure in normal and heart failure (HF) sheep similarly to ANP responses. In contrast to ANP, which in HF produced a diuresis/natriuresis, this analogue was without significant renal effect. Conversely, ANP-DGD induced marked stepwise increases in urinary cGMP, urine volume, and sodium excretion in HF comparable to ANP, but without accompanying vasodilatory effects. All peptides increased packed cell volume relative to control in both states, and in HF, decreased left atrial pressure. In response to ANP-DRD-induced blood pressure reductions, plasma renin activity rose compared to control only during the high dose in normals, and not at all in HF-suggesting relative renin inhibition, with no increase in aldosterone in either state, whereas renin and aldosterone were both significantly reduced by ANP-DGD in HF.. These ANP analogues exhibit distinct vasodilatory (ANP-DRD) and diuretic/natriuretic (ANP-DGD) activities, and therefore have the potential to provide precision therapy for ADHF patients with differing pathophysiological derangement of pressure-volume homeostasis.

Topics: Aldosterone; Animals; Atrial Natriuretic Factor; Cyclic GMP; Disease Models, Animal; Diuresis; Diuretics; Endothelin-1; Female; Heart Failure; Hemodynamics; Kidney; Natriuresis; Natriuretic Peptide, Brain; Renin; Sheep, Domestic; Vasodilation; Vasodilator Agents; Ventricular Function, Left

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

Natural products still serves as a hope for some illnesses which modern medicine fails to cure. Many people, either knowing their effects or not, are using these herbal products. Treatment of chronic heart failure (CHF) is yet a complicated clinical challenge and there is need to improve or make new therapeutic targets. Finding new agents for CHF is an important subject in cardiovascular drug research. In this study, we evaluated the effects of ten herbals on treatment of CHF on isoproterenol-induced model.. Ninety-six male Wistar rats (16 weeks old) were used in 12 groups. Transthoracic echocardiography was performed on the rats for confirmation of CHF model by decreasing ejection fraction. After 4 weeks' treatment, hearts were removed and blood samples were collected in tubes to measure plasma levels of laboratory findings. Our results showed that the mean of ejection fraction in model rats was 51.82 ± 3.49 percent and all of our used natural products could significantly increase the ejection fraction (P < 0.01). The most effective herbals in improving the ejection fraction were Allium sativum (30.69 %), Peganum harmala (26.08 %) and Apium graveolens (24.09 %). The best results in decreasing NT-ProBNP, was obtained from Allium sativum, Peganum harmala and Berberis vulgaris respectively. Our results showed that none of natural products had toxic effect on renal and liver tissues.. Our results showed that Allium sativum, Peganum harmala and Berberis vulgaris could significantly improve cardiac function by improvement of left ventricular remodeling, lowering hs-CRP and NT-ProBNP and echocardiographic indexes without liver or renal side effects.

Topics: Animals; Apium; Berberis; Disease Models, Animal; Echocardiography; Garlic; Heart Failure; Humans; Isoproterenol; Kidney; Liver; Male; Natriuretic Peptide, Brain; Peganum; Peptide Fragments; Phytotherapy; Plant Extracts; Plants, Medicinal; Rats; Rats, Wistar; Stroke Volume; Ventricular Function, Left

Background Corin is a transmembrane protease that activates ANP and BNP (atrial and B-type natriuretic peptides). Impaired corin expression and function are associated with heart failure. In this study, we characterized a soluble form of corin (sCorin) and examined its effects on cardiac morphology and function in mouse heart failure models. Methods and Results sCorin, consisting of the full-length extracellular fragment of human corin with an engineered activation site, was expressed in Chinese hamster ovary cells, purified from the conditioned medium with affinity chromatography, and characterized in pro-ANP processing assays in vitro and pharmacokinetic studies in mice. Effects of sCorin on mouse models of heart failure induced by left coronary artery ligation and transverse aortic constriction were assessed by ELISA analysis of plasma markers, histologic examination, and echocardiography. We showed that purified and activated sCorin converted pro-ANP to ANP that stimulated cGMP production in cultured cells. In mice, intravenously and intraperitoneally administered sCorin had plasma half-lives of 3.5±0.1 and 8.3±0.3 hour, respectively. In the mouse heart failure models, intraperitoneal injection of sCorin increased plasma ANP, BNP, and cGMP levels; lowered plasma levels of NT-proANP (N-terminal-pro-ANP), angiotensin II, and aldosterone; reduced cardiac hypertrophy and fibrosis; and improved cardiac function. Conclusions We show that sCorin treatment enhanced natriuretic peptide processing and activity, suppressed the renin-angiotensin-aldosterone system, and improved cardiac morphology and function in mice with failing hearts.

Topics: Animals; Atrial Natriuretic Factor; Blotting, Western; Cricetinae; Disease Models, Animal; Heart Failure; Male; Mice; Mice, Inbred C57BL; Myocardium; Natriuretic Peptide, Brain; Recombinant Proteins; Serine Endopeptidases; Ventricular Function, Left

The angiotensin receptor/neprilysin inhibitor Sacubitril/Valsartan (Sac/Val) has been shown to be beneficial in patients suffering from heart failure with reduced ejection fraction (HFrEF). However, the impact of Sac/Val in patients presenting with heart failure with preserved ejection fraction (HFpEF) is not yet clearly resolved. The present study aimed to reveal the influence of the drug on the functionality of the myocardium, the skeletal muscle, and the vasculature in a rat model of HFpEF. Female obese ZSF-1 rats received Sac/Val as a daily oral gavage for 12 weeks. Left ventricle (LV) function was assessed every four weeks using echocardiography. Prior to organ removal, invasive hemodynamic measurements were performed in both ventricles. Vascular function of the carotid artery and skeletal muscle function were monitored. Sac/Val treatment reduced E/é ratios, left ventricular end diastolic pressure (LVEDP) and myocardial stiffness as well as myocardial fibrosis and heart weight compared to the obese control group. Sac/Val slightly improved endothelial function in the carotid artery but had no impact on skeletal muscle function. Our results demonstrate striking effects of Sac/Val on the myocardial structure and function in a rat model of HFpEF. While vasodilation was slightly improved, functionality of the skeletal muscle remained unaffected.

Topics: Aminobutyrates; Angiotensin Receptor Antagonists; Animals; Biphenyl Compounds; Connectin; Cyclic GMP; Diastole; Disease Models, Animal; Drug Combinations; Electrocardiography; Female; Fibrosis; Glycated Hemoglobin; Heart Failure; Muscle, Skeletal; Muscular Atrophy; Natriuretic Peptide, Brain; Peptide Fragments; Phosphorylation; Rats, Mutant Strains; Valsartan; Ventricular Function, Left

Topics: Adult; Aged; Aged, 80 and over; Air Pollutants; Air Pollution; Animals; Anti-Bacterial Agents; Anti-Infective Agents; Anti-Inflammatory Agents; Antibodies, Monoclonal, Humanized; Antigens, Surface; Antineoplastic Agents; Antioxidants; Antiviral Agents; Aporphines; Atherosclerosis; Benzoyl Peroxide; beta Catenin; Biofilms; Biomarkers; Brain; Cannabis; Carcinoma, Squamous Cell; Case-Control Studies; CD4 Lymphocyte Count; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cell Line; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Survival; Child; China; Chlorides; Chlorophyll; Cholesterol, LDL; Coinfection; Corylus; Cross-Sectional Studies; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Developmental Disabilities; Disease Models, Animal; Drug Evaluation, Preclinical; Drug Screening Assays, Antitumor; Electroencephalography; Environmental Exposure; Enzyme Inhibitors; Epilepsy, Generalized; Ethnicity; Female; Fertilization in Vitro; Fluorescent Dyes; Follow-Up Studies; Forecasting; Glutamate Carboxypeptidase II; Glycine; Half-Life; Head and Neck Neoplasms; Health Communication; Heart Ventricles; Hepacivirus; Hepatitis C; Heterosexuality; HIV Infections; Humans; Hypercholesterolemia; Immunoassay; Inhalation Exposure; Isocitrate Dehydrogenase; Laryngeal Neoplasms; Ligands; Light; Lipopolysaccharide Receptors; Liver Cirrhosis; Lung; Lung Neoplasms; Magnetic Resonance Imaging, Cine; Male; Maternal Age; Mechanical Phenomena; Mice; Mice, Nude; Mice, SCID; Microglia; MicroRNAs; Microscopy, Fluorescence; Microsomes, Liver; Middle Aged; Minority Groups; Mitochondrial Membrane Transport Proteins; Models, Biological; Molecular Structure; Molecular Weight; Monte Carlo Method; Muscle Hypotonia; Mutagenesis, Site-Directed; Mutation, Missense; Natriuretic Peptide, Brain; Neoplasms; Nickel; Nitric Oxide; Optical Imaging; Oxides; Particle Size; Particulate Matter; PCSK9 Inhibitors; Peptide Fragments; Phenotype; Photochemotherapy; Photosensitizing Agents; Phytochemicals; Piper; Placenta Growth Factor; Plant Extracts; Plant Leaves; Plant Stems; Platinum; Point-of-Care Testing; Population Surveillance; Postpartum Period; Pregnancy; Pregnancy, Twin; Prevalence; Prospective Studies; Prostatic Neoplasms; Pseudomonas aeruginosa; Pyridines; Pyridones; Racial Groups; Rats; Respiratory Physiological Phenomena; Retrospective Studies; Risk Factors; RNA, Long Noncoding; Semiconductors; Sexual and Gender Minorities; Sexual Behavior; Social Media; Sodium; Solubility; Stereoisomerism; Stochastic Processes; Structure-Activity Relationship; Substance-Related Disorders; Sustained Virologic Response; Sweat; Temperature; Time Factors; Tissue Distribution; Titanium; Transplantation, Heterologous; Tumor Cells, Cultured; Tungsten; Tyramine; United States; Up-Regulation; Ventricular Dysfunction, Left; Ventricular Function, Left; Veterans; Xenograft Model Antitumor Assays; Young Adult

Pentraxin 3 (PTX3) is synthesized locally and released into the circulation, reflecting local inflammation in the cardiovascular system. Therefore, we conducted a study to explore the effect of PTX3 in spontaneously hypertensive heart failure (SHHF) rats. Sprague Dawley (SD) and SHHF rats were treated with recombinant PTX3 protein, and the blood pressure (BP) and echocardiographic parameters were collected. Radioimmunoassay, enzyme immunoassay and enzyme-linked immunosorbent assay (ELISA) were applied to detect plasma levels of atrial/B-type natriuretic peptide (ANP/BNP) and PTX3. The pathological changes in the myocardial tissues were observed by hematoxylin and eosin (HE) and Masson stainings. The mRNA and protein expressions were detected by quantitative real-time reverse-transcription polymerase chain reaction (qPCR) and western blotting. Cardiomyocyte apoptosis was evaluated by TUNEL staining and DNA fragmentation test. Increased plasma concentrations of PTX3 were found in SHHF rats compared with SD rats, which was further enhanced by recombinant PTX3 protein. After injection with recombinant PTX3 protein, the heart function was improved in SHHF rats with the decreased systolic and diastolic BP, and the reduced plasma levels of ANP and BNP. Moreover, PTX3 improved the myocardial damage and interstitial fibrosis in SHHF rats with reduced cardiomyocyte apoptosis and decreased mRNA expressions of pro-inflammatory factors in myocardial tissues. PTX3 could decrease the BP and plasma levels of ANP and BNP in SHHF rats, as well as improve the inflammation, cardiomyocyte apoptosis, and pathological changes of myocardial tissues, suggesting it may be a useful intervention in the treatment of SHHF.

Topics: Animals; Apoptosis; Atrial Natriuretic Factor; Blood Pressure; C-Reactive Protein; Cytokines; Disease Models, Animal; Heart Failure; Hypertension; Male; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats, Inbred SHR; Rats, Sprague-Dawley; Recombinant Proteins; Serum Amyloid P-Component; Ventricular Function, Left

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

Chronic kidney disease (CKD) is a major contributor to the development of heart failure with preserved ejection fraction (HFpEF), whereas the underlying mechanism of cardiorenal HFpEF is still elusive. The aim of this study was to investigate the role of cardiac fibrosis in a rat model of cardiorenal HFpEF and explore whether treatment with Telmisartan, an inhibitor of renin-angiotensin-aldosterone system (RAAS), can ameliorate cardiac fibrosis and preserve diastolic function in cardiorenal HFpEF. Male rats were subjected to 5/6 subtotal nephrectomy (SNX) or sham operation (Sham), and rats were allowed four weeks to recover and form a stable condition of CKD. Telmisartan or vehicle was then administered p.o. (8 mg/kg/d) for 12 weeks. Blood pressure, brain natriuretic peptide (BNP), echocardiography, and cardiac magnetic resonance imaging were acquired to evaluate cardiac structural and functional alterations. Histopathological staining, real-time polymerase chain reaction (PCR) and western blot were performed to evaluate cardiac remodeling. SNX rats showed an HFpEF phenotype with increased BNP, decreased early to late diastolic transmitral flow velocity (E/A) ratio, increased left ventricular (LV) hypertrophy and preserved ejection fraction (EF). Pathology revealed increased cardiac fibrosis in cardiorenal HFpEF rats compared with the Sham group, while chronic treatment with Telmisartan significantly decreased cardiac fibrosis, accompanied by reduced markers of fibrosis (collagen I and collagen III) and profibrotic cytokines (α-smooth muscle actin, transforming growth factor-β1, and connective tissue growth factor). In addition, myocardial inflammation was decreased after Telmisartan treatment, which was in a linear correlation with cardiac fibrosis. Telmisartan also reversed LV hypertrophy and E/A ratio, indicating that Telmisartan can improve LV remodeling and diastolic function in cardiorenal HFpEF. In conclusion, cardiac fibrosis is central to the pathology of cardiorenal HFpEF, and RAAS modulation with Telmisartan is capable of alleviating cardiac fibrosis and preserving diastolic dysfunction in this rat model.

Topics: Angiotensin II Type 1 Receptor Blockers; Animals; Antihypertensive Agents; Blood Flow Velocity; Blood Pressure; Cardio-Renal Syndrome; Diastole; Disease Models, Animal; Echocardiography; Fibrosis; Heart Failure; Hypertrophy, Left Ventricular; Male; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley; Renal Insufficiency, Chronic; Stroke Volume; Telmisartan; Ventricular Function, Left; Ventricular Remodeling

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

Increased Rho-kinase activity in circulating leucocytes is observed in heart failure with reduced ejection fraction (HFrEF). However, there is little information in HFrEF regarding other Rho-kinase pathway components an on the relationship between Rho-kinase and apoptosis. Here, Rho-kinase activation levels and phosphorylation of major downstream molecules and apoptosis levels were measured for the first time both in HFrEF patients and healthy individuals.. Cross-sectional study comparing HFrEF patients (n = 20) and healthy controls (n = 19). Rho-kinase activity in circulating leucocytes (peripheral blood mononuclear cells, PBMCs) was determined by myosin light chain phosphatase 1 (MYPT1) and ezrin-radixin-moesin (ERM) phosphorylation. Rho-kinase cascade proteins phosphorylation p38-MAPK, myosin light chain-2, JAK and JNK were also analysed along with apoptosis.. MYPT1 and ERM phosphorylation were significantly elevated in HFrEF patients, (3.9- and 4.8-fold higher than in controls, respectively). JAK phosphorylation was significantly increased by 300% over controls. Phosphorylation of downstream molecules p38-MAPK and myosin light chain-2 was significantly higher by 360% and 490%, respectively, while JNK phosphorylation was reduced by 60%. Catecholamine and angiotensin II levels were significantly higher in HFrEF patients, while angiotensin-(1-9) levels were lower. Apoptosis in circulating leucocytes was significantly increased in HFrEF patients by 2.8-fold compared with controls and significantly correlated with Rho-kinase activation.. Rho-kinase pathway is activated in PMBCs from HFrEF patients despite optimal treatment, and it is closely associated with neurohormonal activation and with apoptosis. ROCK cascade inhibition might induce clinical benefits in HFrEF patients, and its assessment in PMBCs could be useful to evaluate reverse remodelling and disease regression.

Topics: Angiotensins; Animals; Antigens, CD; Apoptosis; Catecholamines; Cytokines; Cytoskeletal Proteins; Disease Models, Animal; Enzyme Activation; Female; Heart Failure; Humans; Janus Kinase 2; Leukocytes, Mononuclear; Male; Membrane Proteins; Microfilament Proteins; Middle Aged; Myocardium; Myosin-Light-Chain Phosphatase; Natriuretic Peptide, Brain; Phosphorylation; Rats; rho-Associated Kinases; Signal Transduction; Stroke Volume; Systole; Ventricular Remodeling

There is little information in the sepsis treatment guidelines on the prevention and treatment of cognitive dysfunction after sepsis. This study aimed to explore whether Recombinant human brain natriuretic peptide (rhBNP) has protective effects against sepsis-associated encephalopathy (SAE) in a mouse model. The results showed that 50 μg/kg of rhBNP significantly improved the 14-day survival of cecal ligation and puncture (CLP)-induced septic mice and mitigated cognitive dysfunction and anxiety. Fourteen days after CLP surgery, septic mice showed increased BBB permeability and neuronal apoptosis. rhBNP treatment significantly reduced pathological changes in the brain of CLP mice. Meanwhile, rhBNP therapy also reduced the level of inflammatory cytokines in the hippocampus, possibly via inhibiting the TLR4-NF-κB pathway. These results indicate that rhBNP may be a promising drug for the treatment of SAE.

Topics: Animals; Apoptosis; Blood-Brain Barrier; Brain; Brain Diseases; Disease Models, Animal; Humans; Male; Mice; Mice, Inbred C57BL; Natriuretic Peptide, Brain; Neurons; NF-kappa B; Recombinant Proteins; Sepsis; Signal Transduction; Toll-Like Receptor 4

Doxorubicin is a widely used anticancer drug that causes dose-related cardiotoxicity. The exact mechanisms of doxorubicin toxicity are still unclear, partly because most in vitro studies have evaluated the effects of short-term high-dose doxorubicin treatments. Here, we developed an in vitro model of long-term low-dose administration of doxorubicin utilizing human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Moreover, given that current strategies for prevention and management of doxorubicin-induced cardiotoxicity fail to prevent cancer patients developing heart failure, we also investigated whether the GATA4-targeted compound 3i-1000 has cardioprotective potential against doxorubicin toxicity both in vitro and in vivo. The final doxorubicin concentration used in the chronic toxicity model in vitro was chosen based on cell viability data evaluation. Exposure to doxorubicin at the concentrations of 1-3 µM markedly reduced (60%) hiPSC-CM viability already within 48 h, while a 14-day treatment with 100 nM doxorubicin concentration induced only a modest 26% reduction in hiPCS-CM viability. Doxorubicin treatment also decreased DNA content in hiPSC-CMs. Interestingly, the compound 3i-1000 attenuated doxorubicin-induced increase in pro-B-type natriuretic peptide (proBNP) expression and caspase-3/7 activation in hiPSC-CMs. Moreover, treatment with 3i-1000 for 2 weeks (30 mg/kg/day, i.p.) inhibited doxorubicin cardiotoxicity by restoring left ventricular ejection fraction and fractional shortening in chronic in vivo rat model. In conclusion, the results demonstrate that long-term exposure of hiPSC-CMs can be utilized as an in vitro model of delayed doxorubicin-induced toxicity and provide in vitro and in vivo evidence that targeting GATA4 may be an effective strategy to counteract doxorubicin-induced cardiotoxicity.

Topics: Animals; Antibiotics, Antineoplastic; Cardiotoxicity; Caspases, Effector; Cell Line; Cell Survival; Disease Models, Animal; Doxorubicin; GATA4 Transcription Factor; Heart Diseases; Humans; Induced Pluripotent Stem Cells; Male; Myocytes, Cardiac; Natriuretic Peptide, Brain; Protective Agents; Protein Precursors; Rats, Sprague-Dawley; Rats, Wistar; Signal Transduction; Stroke Volume; Time Factors; Ventricular Function, Left

Berberine was reported to exert beneficial effects on cardiac hypertrophy. However, its cellular and molecular mechanisms still remained unclear.. Cardiac hypertrophy was induced in male Sprague-Dawley (SD) rats by transverse aorta constriction (TAC), with or without 6-week treatment of berberine. Echocardiography was performed to evaluate cardiac function. Rats were then sacrificed for histological assay, with detection for proteins and mRNA. H9c2 cells were pretreated with berberine of different concentrations (0, 1 μM, and 10 μM), followed by treatment with 2 μM norepinephrine (NE). Cells of different groups were measured for cell surface area, with mRNA detected by qRT-PCR and proteins by western blot.. Compared with the sham group, rats of the TAC group showed significantly increased cardiac hypertrophy and fibrosis, which could be ameliorated by treatment with berberine. Western blot showed that mammalian target of rapamycin (mTOR) signaling-related protein expressions, including phospho-mTOR, phospho-4EBP1, and phospho-p70 S6K (Thr389), but not phospho-p70 S6K (Ser371), were significantly increased in the TAC group, which were inhibited by berberine treatment. H9c2 cells were treated with NE to induce hypertrophy with increased cell surface area and mRNA expressions of anp and bnp. Berberine of 10 μM, but not 1 μM, significantly ameliorated NE-induced hypertrophy and inhibited protein expressions of mTOR signaling pathway similar to those in the rat model.. Berberine can exert cardioprotective effects on both pressure-overloaded cardiac hypertrophy and failure in vivo and NE-induced hypertrophy in vitro. Our results suggest berberine could be a potential treatment for patients with cardiac hypertrophy and failure.

Topics: Animals; Atrial Natriuretic Factor; Berberine; Cell Line; Disease Models, Animal; Fibrosis; Hypertrophy, Left Ventricular; Intracellular Signaling Peptides and Proteins; Male; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phosphorylation; Protein Kinase Inhibitors; Rats, Sprague-Dawley; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; TOR Serine-Threonine Kinases; Ventricular Function, Left; Ventricular Remodeling

Myocardial infarction (MI) increases myocardial fibrosis (MF) and subsequent cardiac remodeling. Cholecystokinin octapeptide (CCK-8) is expressed in cardiomyocytes and plays an important role in cardiovascular regulation. In this study, we intend to use a rat model of myocardial infarction to evaluate the effects of CCK-8 on myocardial fibrosis and cardiac remodeling.. Male Sprague-Dawley rats were separated into 3 groups: sham operation, MI + NaCl, and MI + CCK-8. All rats were subjected to left coronary artery ligation to induce MI or sham operation and then treated with CCK-8 or saline for 28 days. After 4 weeks, echocardiography was performed to assess cardiac function and myocardial fibrosis was evaluated using H&E and Masson's Trichrome-stained sections. The levels of BNP, CCK-8 in the plasma of all rats were detected by ELISA; RNA sequencing (RNA-seq) analysis was also adapted to detect differentially expressed genes in myocardial tissues of each group. Myocardial expression of fibrosis markers was analyzed by western blotting, immunohistochemistry and qRT-PCR.. CCK-8 was demonstrated to improve left ventricular function and results of H&E staining, Masson's trichrome staining, immunohistochemistry and western blotting showed that CCK-8 attenuated MF. Gene expression profiles of the left ventricles were analysed by RNA-seq and validated by qRT-PCR. Cardiac fibrosis genes were downregulated by CCK-8 in the left ventricle.. CCK-8 can alleviate fibrosis in the noninfarcted regions and delay the left ventricular remodeling and the progress of heart failure in a MI rat model.

Topics: Animals; Cardiomyopathies; Disease Models, Animal; Echocardiography; Gene Expression Regulation; Heart Ventricles; Male; Myocardial Infarction; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley; RNA-Seq; Sincalide; Ventricular Remodeling

Topics: Animals; Anti-Inflammatory Agents; CD4-Positive T-Lymphocytes; Cell Proliferation; Cytokines; Disease Models, Animal; Humans; Jurkat Cells; Mice, Inbred C57BL; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Natriuretic Peptide, Brain; Phosphatidylinositol 3-Kinase; Phosphorylation; Proto-Oncogene Proteins c-akt; Recombinant Proteins; Signal Transduction; TOR Serine-Threonine Kinases

Topics: Animals; Atrial Natriuretic Factor; Bacterial Proteins; Bacterial Toxins; Caco-2 Cells; Cardiovascular Diseases; Cell Line, Tumor; Cells, Cultured; Clostridioides difficile; Clostridium Infections; Cytokines; Disease Models, Animal; Enterotoxins; Human Umbilical Vein Endothelial Cells; Humans; Inflammation; Intestines; Natriuretic Peptide, Brain; Neutrophils; Serum Albumin, Human; Vascular Endothelial Growth Factor A; Zebrafish

Both progenitor and differentiated cells were previously shown to secrete cardioprotective substances, but so far there has been no direct comparison of the paracrine effects of the two cell types on heart failure. The study sought to compare the paracrine effect of selected progenitors and the corresponding non-progenitor mononuclear cardiac cells on the cardiac function of transgenic heart failure mice. In addition, we aimed to further enhance the paracrine effect of the cells via pretreatment with the heart failure mediator aldosterone.. Transgenic heart failure mice were injected with the supernatant of murine cardiac stem cell antigen-1 positive (Sca-1+) and negative (Sca-1-) cells with or without aldosterone pretreatment. Cardiac function was determined using small animal magnetic resonance imaging. In addition, heart failure markers were determined using enzyme-linked immunosorbent assay, RT-PCR, and bead-based multiplexing assay. While only the secretome of aldosterone pretreated Sca-1+ cells led to a significant improvement in cardiac function, N-terminal pro brain natriuretic peptide plasma levels were significantly lower and galectin-1 levels significantly higher in mice that were treated with either kind of secretome compared with untreated controls.. In this first direct comparison of the paracrine effects of progenitor cells and a heterogeneous population of mononuclear cardiac cells the supernatants of both cell types showed cardioprotective properties which might be of great relevance for endogenous repair. During heart failure raised aldosterone levels might further increase the paracrine effect of progenitor cells.

Topics: Aldosterone; Animals; Ataxin-1; Cells, Cultured; Disease Models, Animal; Female; Fibrosis; Galectin 1; Heart Failure; Interleukin-12; Male; Mice, Transgenic; Myocardium; Natriuretic Peptide, Brain; Paracrine Communication; Peptide Fragments; Phenotype; Secretory Pathway; Signal Transduction; Stem Cells; Ventricular Remodeling

Vasopressin and apelin are reciprocally regulated hormones which are implicated in the pathophysiology of heart failure and the regulation of metabolism; however, little is known about their interactions under pathological conditions. In this study, we determined how post-infarct heart failure (HF) and a high fat diet (HFD) affect expression of the apelin APJ receptor (APJR) and the V1a (V1aR) and V1b (V1bR) vasopressin receptors in the hypothalamus, the heart, and the retroperitoneal adipose tissue. We performed experiments in male 4-week-old Sprague Dawley rats. The animals received either a normal fat diet (NFD) or a HFD for 8 weeks, then they underwent left coronary artery ligation to induce HF or sham surgery (SO), followed by 4 weeks of NFD or HFD. The HF rats showed higher plasma concentration of NT-proBNP and copeptin. The HF reduced the APJR mRNA expression in the hypothalamus. The APJR and V1aR protein levels in the hypothalamus were regulated both by HF and HFD, while the V1bR protein level in the hypothalamus was mainly influenced by HF. APJR mRNA expression in the heart was significantly higher in rats on HFD, and HFD affected the reduction of the APJR protein level in the right ventricle. The regulation of APJR, V1aR and V1bR expression in the heart and the retroperitoneal adipose tissue were affected by both HF and HFD. Our study demonstrates that HF and HFD cause significant changes in the expression of APJR, V1aR and V1bR, which may have an important influence on the cardiovascular system and metabolism.

Topics: Animals; Apelin Receptors; Diet, High-Fat; Disease Models, Animal; Glycopeptides; Heart Failure; Hypothalamus; Male; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain; Peptide Fragments; Rats; Rats, Sprague-Dawley; Receptors, Vasopressin

The aim of the present study was to determine the roles of microRNA (miR)-146a on myocardial infarction (MI)-induced heart failure and cardiac remodeling. Experiments were carried out in Sprague-Dawley rats treated with ligation of left coronary artery to induce heart failure, and in primary neonatal rat cardiac fibroblasts (CFs) and cardiomyocytes treated with angiotensin (Ang) II. Four weeks after MI, rats were injected with miR-146a antagomiR or agomiR via tail vein. After 2 weeks of injection, the rats were killed. In MI rats, left ventricle (LV) ejection fraction and fractional shortening were reduced, and LV volumes in diastole and systole were increased, which were reversed by miR-146a antagomiR, and further exacerbated after miR-146a agomiR treatment. Administration of miR-146a antagomiR improved the decreases of LV ±dp/dtmax and LV systolic pressure (LVSP), and the increase in LV end-diastolic pressure (LVEDP) of MI rats, but miR-146a agomiR deteriorated the LV ±dp/dtmax, LVSP and LVEDP. The increases in the levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), collagen I and collagen III in the heart, and ST2 and norepinephrine in the serum of MI rats were inhibited by miR-146a antagomiR, but aggravated after miR-146a agomiR treatment. The increases of collagen I and collagen III levels induced by Ang II in CFs, and the increases of ANP and BNP levels induced by Ang II in cardiomyocytes were inhibited by miR-146a antagomiR, but aggravated by miR-146a agomiR. These results demonstrated that inhibition of miR-146a improved cardiac dysfunction and cardiac remodeling in heart failure rats.

Topics: Angiotensin II; Animals; Animals, Newborn; Antagomirs; Atrial Remodeling; Disease Models, Animal; Heart; Heart Failure; Humans; MicroRNAs; Myocardial Infarction; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley; Ventricular Function, Left; Ventricular Remodeling

BACKGROUND The study aimed to investigate the expression of brain natriuretic peptide (BNP) and natriuretic peptide receptor A (NPR-A) in L6-S1 dorsal root ganglia (DRG) in a rat model of chronic nonbacterial prostatitis (CNP). MATERIAL AND METHODS One hundred specific pathogen-free (SPF) male Sprague-Dawley rats were randomly divided into a control group (N=50) and a study group (N=50). The control group underwent prostatic injection of 0.1 ml of normal saline on days 3, 7, 10, 14, and 28. The study group, or rat model of CNP, underwent prostatic injection of 0.1 ml of complete Freund's adjuvant on days 3, 7, 10, 14, and 28. At the end of the study, the rats were euthanized, and the prostate tissues and L6-S1 DRG were removed. Histology was performed on the prostate tissue from the rats in the study group and control group. Real-time fluorescence-based quantitative polymerase chain reaction (PCR) and Western blot were used to study the expression of BNP and NPR-A mRNA and protein in the DRG from the rats in the study group and control group. RESULTS In the rat model of CNP, the expression of BNP and NPR-A were significantly increased in L6-S1 DRG compared with the controls. CONCLUSIONS In a rat model of CNP, the increased expression of BNP and NPR-A in L6-S1 DRG may have a role in pain signaling pathways associated with chronic prostatitis.

Topics: Animals; China; Disease Models, Animal; Freund's Adjuvant; Ganglia, Spinal; Gene Expression Regulation; Male; Natriuretic Peptide, Brain; Pain; Prostatitis; Proteins; Rats; Rats, Sprague-Dawley; Receptors, Atrial Natriuretic Factor; RNA, Messenger; Signal Transduction; Transcriptome

Heart failure-associated morbidity and mortality is largely attributable to extensive and unregulated cardiac remodelling. Roselle (Hibiscus sabdariffa) calyces are enriched with natural polyphenols known for antioxidant and anti-hypertensive effects, yet its effects on early cardiac remodelling in post myocardial infarction (MI) setting are still unclear. Thus, the aim of this study was to investigate the actions of roselle extract on cardiac remodelling in rat model of MI. Male Wistar rats (200-300 g) were randomly allotted into three groups: Control, MI, and MI + Roselle. MI was induced with isoprenaline (ISO) (85 mg/kg, s.c) for two consecutive days followed by roselle treatment (100 mg/kg, orally) for 7 days. Isoprenaline administration showed changes in heart weight to body weight (HW/BW) ratio. MI was especially evident by the elevated cardiac injury marker, troponin-T, and histological observation. Upregulation of plasma levels and cardiac gene expression levels of inflammatory cytokines such as interleukin (IL)-6 and IL-10 was seen in MI rats. A relatively high percentage of fibrosis was observed in rat heart tissues with over-expression of collagen (Col)-1 and Col-3 genes following isoprenaline-induced MI. On top of that, cardiomyocyte areas were larger in heart tissues of MI rats with upregulation of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) gene expression, indicating cardiac hypertrophy. Interestingly, roselle supplementation attenuated elevation of plasma troponin-T, IL-6, IL10, and gene expression level of IL-10. Furthermore, reduction of cardiac fibrosis and hypertrophy were observed. In conclusion, roselle treatment was able to limit early cardiac remodelling in MI rat model by alleviating inflammation, fibrosis, and hypertrophy; hence, the potential application of roselle in early adjunctive treatment to prevent heart failure.

Topics: Animals; Atrial Natriuretic Factor; Cardiovascular Agents; Collagen Type I; Collagen Type III; Disease Models, Animal; Fibrosis; Heart Ventricles; Hibiscus; Hypertrophy, Left Ventricular; Inflammation Mediators; Interleukin-10; Interleukin-6; Isoproterenol; Male; Myocardial Infarction; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats, Wistar; Troponin T; Ventricular Function, Left; Ventricular Remodeling

Heart failure (HF) progression can be prevented by an inhibitor of the mammalian target of rapamycin and an autophagy enhancer rapamycin. This current study aimed to investigate the effect of rapamycin on HF progression and myocardial cells apoptosis.. HF rats were injected with low-, middle-, and high-dose rapamycin. Echocardiography, hematoxylin-eosin staining, plasma brain natriuretic peptide, myocardial cells apoptosis, and Akt activation in rapamycin-treated rats were detected.. HF rats showed reduced cardiac functions, destructive pathological changes in the myocardium, enhanced Akt activation and myocardial cells apoptosis. However, rapamycin reversed all the changes in a dose-dependent manner. Cardiac functions were enhanced by rapamycin. Myocardial cells apoptotic percentage, Akt expression, and pathological changes of the myocardium in HF rats were inhibited by rapamycin administration.. Rapamycin protected against myocardial hypertrophy and myocardial cells apoptosis in HF rats in a dose-dependent manner.

Topics: Animals; Apoptosis; Autophagy; Disease Models, Animal; Dose-Response Relationship, Drug; Echocardiography; Gene Expression Regulation; Heart; Heart Failure; Humans; Myocardium; Natriuretic Peptide, Brain; Proto-Oncogene Proteins c-akt; Rats; Signal Transduction; Sirolimus

Pulmonary arterial hypertension (PAH) is more prevalent in females. Paradoxically, female patients have better right ventricular (RV) function and higher survival rates than males. However, the effects of 17β-estradiol (E2) on RV function in PAH has not been studied. Twenty-four male rats were exposed to monocrotaline (MCT) to induce experimental PAH, while treated with E2 or vehicle respectively. Together with eight control rats, thirty-two rats were examined by echocardiography 4 weeks after drug administration. Echocardiographic measurement of RV function included: tricuspid annular plane systolic excursion (TAPSE), RV index of myocardial performance (RIMP), RV fractional area change (RVFAC) and tricuspid annular systolic velocity (s'). RV free wall longitudinal strain (RVLS

Topics: Animals; Biomarkers; Disease Models, Animal; Echocardiography; Estradiol; Fibrosis; Heart Ventricles; Hemodynamics; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Male; Monocrotaline; Natriuretic Peptide, Brain; Rats, Sprague-Dawley; Time Factors; Ventricular Dysfunction, Right; Ventricular Function, Right; Ventricular Remodeling

Drugs facilitating the cardioprotective effects of natriuretic peptides are introduced in heart failure treatment. ANP and BNP also stimulate lipolysis and increase circulating concentrations of free fatty acids (FFAs); an aspect, however, thought to be confined to primates. We examined the lipolytic effect of natriuretic peptide infusion in healthy young men and evaluated the effect in a porcine model of myocardial ischemia and reperfusion. Six young healthy normotensive men underwent infusion with ANP, BNP, or CNP for 20 min. Blood samples were collected before, during, and after infusion for measurement of FFAs. In a porcine model of myocardial ischemia and reperfusion, animals were infused for 3 h with either BNP (n = 7) or saline (n = 5). Blood samples were collected throughout the infusion period, and cardiac tissue was obtained after infusion for lipid analysis. In humans, ANP infusion dose-dependently increased the FFA concentration in plasma 2.5-10-fold (baseline vs. 0.05 μg/kg/min P < 0.002) and with BNP 1.6-3.5-fold (P = 0.001, baseline vs. 0.02 μg/kg/min) 30 min after initiation of infusion. Infusion of CNP did not affect plasma FFA. In pigs, BNP infusion induced a 3.5-fold increase in plasma FFA (P < 0.0001), which remained elevated throughout the infusion period. Triglyceride content in porcine right cardiac ventricle tissue increased ∼5.5 fold in animals infused with BNP (P = 0.02). Natriuretic peptide infusion has similar lipolytic activity in human and pig. Our data suggest that short-term infusion increases the cardiac lipid content, and that the pig is a suitable model for studies of long-term effects mediated by natriuretic peptides.

Topics: Animals; Atrial Natriuretic Factor; Disease Models, Animal; Fatty Acids, Nonesterified; Female; Heart; Humans; Infusions, Intravenous; Lipolysis; Male; Models, Animal; Myocardial Ischemia; Myocardium; Natriuretic Peptide, Brain; Sus scrofa; Triglycerides

Recent clinical studies have demonstrated that serum fibroblast growth factor 23 (FGF23) levels have a significant association with left ventricular hypertrophy (LVH). Although LVH is commonly seen in hypertensive patients, the association between FGF23, hypertension, and LVH remains unclear. We aimed to examine the changes in serum and intracardiac FGF23 during the progression of hypertension using spontaneously hypertensive rats (SHR).. Male SHR comprised the experimental group (HT group) and Wistar Kyoto rats served as controls. At 10 weeks, urinary and blood biochemical analyses and blood pressure measurements were performed for both the groups. At 18 weeks, the rats were sacrificed: urinary and blood biochemical analyses and real-time PCR were performed.. At 18 weeks, the relative heart weight and serum N-terminal pro-brain natriuretic peptide and aldosterone levels were significantly greater in the HT group. Serum calcium and phosphate levels were significantly lower, while serum FGF23 levels were significantly higher in the HT group compared to the control group. Further analyses showed that the mRNA expression of FGF23 in the heart was significantly increased in the HT group compared to the control group. Both serum FGF23 levels and intracardiac mRNA expression of FGF23 showed significant correlation with the relative heart weight.. During LVH progression, serum and intracardiac FGF23 increased in hypertension. Although it is unclear whether the change in FGF23 is the cause or result of LVH, the interaction between FGF23 and aldosterone may be associated with the development of LVH in hypertension.

Topics: Aldosterone; Animals; Bone and Bones; Chronic Kidney Disease-Mineral and Bone Disorder; Disease Models, Animal; Fibroblast Growth Factors; Hypertension; Hypertrophy, Left Ventricular; Male; Myocardium; Natriuretic Peptide, Brain; Organ Size; Peptide Fragments; Rats, Inbred SHR; Rats, Inbred WKY

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

Luteolin (LTL) serves essential roles in a wide variety of biological processes. Lipopolysaccharide (LPS) can lead to myocardial hypertrophy and autophagy. However, the roles of LTL on LPS‑induced cardiomyocyte hypertrophy and autophagy in rat cardiomyocytes have not yet been fully elucidated. In the present study, the morphology of cultured rat cardiomyocytes was observed under an inverted microscope. Cell viability was detected by MTT assay. α‑Actinin and microtubule‑associated protein 1 light chain 3 (LC3) expression levels were measured by immunofluorescence assay. In addition, the expression levels of atrial natriuretic peptide/brain natriuretic peptide (ANP/BNP), LC3, and autophagy‑ and Wnt signaling pathway‑associated genes were analyzed by reverse transcription‑quantitative polymerase chain reaction or western blot assays. The results indicated that LTL increased the cell viability of cardiomyocytes treated with LPS. LTL decreased the expression of cardiac hypertrophy associated markers (ANP and BNP). LTL decreased α‑actinin and LC3 expression levels in LPS‑treated cardiomyocytes. It was also demonstrated that LTL suppressed the mRNA and protein expression levels of LPS‑mediated autophagy and Wnt signaling pathway‑associated genes. In addition, it was demonstrated that silencing of β‑catenin inhibited LPS‑induced cardiomyocyte hypertrophy and the formation of autophagosomes. Thus, the present study suggested that LTL protected against LPS‑induced cardiomyocyte hypertrophy and autophagy in rat cardiomyocytes.

Topics: Animals; Atrial Natriuretic Factor; Autophagy; Disease Models, Animal; Gene Expression; Humans; Hypertrophy; Lipopolysaccharides; Luteolin; Microtubule-Associated Proteins; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats; RNA, Messenger; Signal Transduction

Topics: Animals; Atrial Natriuretic Factor; Benzoxazoles; Cell Hypoxia; Cell Line; Disease Models, Animal; Drugs, Chinese Herbal; Hemeproteins; Hypertension, Pulmonary; Male; Myocytes, Cardiac; NADPH Oxidase 2; NADPH Oxidase 4; NADPH Oxidases; Natriuretic Peptide, Brain; Peroxidases; Rats, Sprague-Dawley; Salvia miltiorrhiza; Triazoles; Ventricular Remodeling

There is still no satisfactory large-animal model of ischemic heart failure (IHF) with ideal survival rate and model time. The aim of this study is to explore a novel chronic IHF model in swine. 23 healthy Ba-Ma miniature pigs were included. Pigs in the experimental group underwent multiple strategic ligations on side branches of the left anterior descending (LAD) and circumflex coronary arteries. One week later, sequential intervention occlusion of the distal end of the LAD trunk was performed. In the experimental groups, LV end-diastolic (LVEDV) and end-systolic volume (LVESV) gradually increased starting at 4 weeks post operation. At 12 WPO, LVEDV increased from 45.0 ± 2.9 ml at baseline to 110.0 ± 9.8 ml and LVESV increased from 17.0 ± 1.4 ml at baseline to 42.0 ± 3.6 ml. Meanwhile, left ventricular ejection fraction significantly decreased from 73.8 ± 4.2 % at baseline to 31.0 ± 2.5%. According to histomorphometric assessment, viable cells were observed in infarction lesions, indicating the model has replicated the structural and functional features of chronic IHF.

Topics: Animals; C-Reactive Protein; Coronary Angiography; Coronary Vessels; Disease Models, Animal; Electrocardiography; Heart Failure; Magnetic Resonance Imaging; Male; Models, Biological; Myocardial Ischemia; Natriuretic Peptide, Brain; Peptide Fragments; Postoperative Care; Swine; Swine, Miniature; Ventricular Function, Left; Ventricular Remodeling

Sodium glucose co-transporter 2 inhibitor (SGLT2i), a new class of anti-diabetic drugs acting on inhibiting glucose resorption by kidneys, is shown beneficial in reduction of heart failure hospitalization and cardiovascular mortality. The mechanisms remain unclear. We hypothesized that SGLT2i, empagliflozin can improve cardiac hemodynamics in non-diabetic hypertensive heart failure.. The hypertensive heart failure model had been created by feeding spontaneous hypertensive rats (SHR) with high fat diet for 32 weeks (total n = 13). Half SHRs were randomized to be administered with SGLT2i, empagliflozin at 20 mg/kg/day for 12 weeks. After evaluation of electrocardiography and echocardiography, invasive hemodynamic study was performed and followed by blood sample collection and tissue analyses. Empagliflozin exhibited cardiac (improved atrial and ventricular remodeling) and renal protection, while plasma glucose level was not affected. Empagliflozin normalized both end-systolic and end-diastolic volume in SHR, in parallel with parameters in echocardiographic evaluation. Empagliflozin also normalized systolic dysfunction, in terms of the reduced maximal velocity of pressure incline and the slope of end-systolic pressure volume relationship in SHR. In histological analysis, empagliflozin significantly attenuated cardiac fibrosis in both atrial and ventricular tissues. The upregulation of atrial and ventricular expression of PPARα, ACADM, natriuretic peptides (NPPA and NPPB), and TNF-α in SHR, was all restored by treatment of empagliflozin.. Empagliflozin improves hemodynamics in our hypertensive heart failure rat model, associated with renal protection, attenuated cardiac fibrosis, and normalization of HF genes. Our results contribute some understanding of the pleiotropic effects of empagliflozin on improving heart function.

Topics: Animals; Atrial Function, Left; Atrial Natriuretic Factor; Benzhydryl Compounds; Diet, High-Fat; Disease Models, Animal; Fatty Acids; Fibrosis; Gene Expression Regulation; Glucosides; Heart Failure; Hemodynamics; Hypertension; Male; Myocardium; Natriuretic Peptide, Brain; Rats, Inbred SHR; Rats, Inbred WKY; Recovery of Function; Sodium-Glucose Transporter 2 Inhibitors; Tumor Necrosis Factor-alpha; Ventricular Function, Left; Ventricular Remodeling

The Lieber-DeCarli alcoholic liquid diet is a classical method for establishing animal models of alcoholic cardiomyopathy (ACM). No study has reported whether the AIN-93 diet, which is widely used as a standard diet for both long-term and short-term studies with laboratory animals, could be used to construct the ACM animal model. The present study intended to investigate whether the AIN-93 diet could be used to establish a mouse ACM model.. Twenty-four C57BL/6 male mice were randomly divided into 4 equally sized groups. In ethanol (EtOH)-fed groups, mice were fed a 4%-EtOH (w/v, 28% of total calories) alcoholic liquid diet of Lieber-DeCarli or the AIN-93 diet for chronic alcohol exposure for 180 days. In control-fed groups, mice were fed with non-EtOH liquid diets with the same calories as EtOH-fed groups. Morphological observations of the hearts and molecular investigation of the brain natriuretic peptide (BNP) were carried out by echocardiography, hematoxylin and eosin (H&E) and immunohistochemistry (IHC) staining, real-time quantitative polymerase chain reaction (qPCR), and enzyme-linked immunosorbent assay.. Echocardiography showed that mice fed with either the 4%-EtOH Lieber-DeCarli diet or the 4%-EtOH AIN-93 diet had dilated ventricles and poor cardiac function. IHC staining of BNP, qPCR of BNP mRNA, and plasma concentration of BNP showed an up-regulated expression in mice fed with both the 4%-EtOH Lieber-DeCarli and 4%-EtOH AIN-93 diets. Less fatty liver was also observed in mice fed the AIN-93 alcoholic diet than those fed the Lieber-DeCarli alcoholic diet.. The AIN-93 alcoholic liquid diet can be used to establish ACM animal models, as with the conventional Lieber-DeCarli alcoholic liquid diet.

Topics: Animals; Cardiomyopathy, Alcoholic; Central Nervous System Depressants; Diet; Disease Models, Animal; Echocardiography; Ethanol; Fatty Liver; Heart Ventricles; Immunohistochemistry; Male; Mice; Mice, Inbred C57BL; Myocardium; Natriuretic Peptide, Brain

Doxorubicin-induced (DXR) cardiomyopathy is a serious health issue in oncology patients. Effective treatment of this clinical situation still remains to be discovered. In this experimental animal study, we aimed to define therapeutic effects of liraglutide, oxytocin and granulocyte colony-stimulating factor in DXR-induced cardiomyopathy model. 40 male Sprague-Dawley rats were included to study. 32 rats were given doxorubicin (DXR) for cardiomyopathy model. DXR was administered intraperitonally (i.p.) at every other day of 2.5 mg/kg/day at six times. Eight rats were taken as normal group and no treatment was performed. 32 rats given doxorubicin were divided into 4 groups. Group 1 rats were assigned to a placebo group and was given with a 0.9% NaCl saline solution at a dose of 1 ml/kg/day i.p. (DXR + saline), Group 2 rats were given with 1.8 mg/kg/day of Liraglutide i.p. (DXR + LIR), Group 3 rats were given with 160 μg/kg/day oxytocin i.p. (DXR + OX), Group 4 rats were given with 100 μg/kg/day filgrastim i.p. (DXR + G-CSF). All medications were given for 15 days. On day 16, under anesthesia, ECG was recorded from derivation I. After that, blood samples were taken by tail vein puncture for biochemical analysis. Finally, the animals were euthanized and the heart removed and prepared for immunohistochemical examination. All three treatments were shown to ameliorate the toxic effect of doxorubicin in cardiac tissue with the best results in DXR + OX group. DXR + OX group had the most preserved tissue integrity examined by light microscopy, least immune expression level of CASPASE-3 (5.3 ± 0.9) (p < 0.001) the highest ECG QRS wave voltage amplitude (0.21 ± 0.008 mV) (p < 0.00001) least plasma MDA (115.3 ± 19.8 nm) (p < 0.001), TNF-alpha (26.6 ± 3.05 pg/ml) (p < 0.001), pentraxin-3 (2.7 ± 0.9 ng/ml) (p < 0.001), Troponin T (1.4 ± 0.08 pg/ml) (p < 0.001), pro-BNP (11.1 ± 3.6 pg/ml) (p < 0.001) levels among all three treatment groups. Consistent with previous literature, we found that OX treatment decreased oxidative, apoptotic and inflammatory activity in DXR-induced cardiomyopathy rat model as well as provided better tissue integrity and better results in clinically relevant measures of ECG assessment, plasma Troponin T and pro-BNP levels. LIR and G-CSF treatment caused similar results with less powerful effects. Our findings suggest that with the best results in OX treatment group, all three agents including LIR and G-CSF attenuates DXR-induced cardiomyopathy in

Topics: Animals; Apoptosis; C-Reactive Protein; Cardiomyopathies; Cardiotoxicity; Caspase 3; Disease Models, Animal; Doxorubicin; Granulocyte Colony-Stimulating Factor; Heart Rate; Humans; Inflammation Mediators; Lipid Peroxidation; Liraglutide; Malondialdehyde; Myocytes, Cardiac; Natriuretic Peptide, Brain; Oxidative Stress; Oxytocin; Rats, Sprague-Dawley; Serum Amyloid P-Component; Signal Transduction; Troponin T; Tumor Necrosis Factor-alpha

Kawasaki disease (KD) vasculitis is an acute febrile illness of childhood characterized by systemic vasculitis of unknown origin, and is the most common cause of acquired heart disease among children in the United States. While  histological evidence of myocarditis can be found in all patients with acute KD, only a minority of patients are clinically symptomatic and a subset demonstrate echocardiographic evidence of impaired myocardial function, as well as increased left ventricular mass, presumed to be due to myocardial edema and inflammation. Up to a third of KD patients fail to respond to first-line therapy with intravenous immunoglobulin (IVIG), and the use of interleukin (IL)-1 receptor antagonist (IL-1Ra, anakinra) is currently being investigated as an alternative therapeutic approach to treat IVIG-resistant patients. In this study, we sought to investigate the effect of IL-1Ra on myocardial dysfunction and its relation to myocarditis development during KD vasculitis. We used the Lactobacillus casei cell-wall extract (LCWE)-induced murine model of KD vasculitis and investigated the effect of IL-1Ra pretreatment on myocardial dysfunction during KD vasculitis by performing histological, magnetic resonance imaging (MRI) and echocardiographic evaluations. IL-1Ra pretreatment significantly reduced KD-induced myocardial inflammation and N-terminal pro B-type natriuretic peptide (NT-proBNP) release. Both MRI and echocardiographic studies on LCWE-injected KD mice demonstrated that IL-1Ra pretreatment results in an improved ejection fraction and a normalized left ventricular function. These findings further support the potential beneficial effects of IL-1Ra therapy in preventing the cardiovascular complications in acute KD patients, including the myocarditis and myocardial dysfunction associated with acute KD.

Topics: Animals; Cardiomyopathies; Disease Models, Animal; Immunoglobulins, Intravenous; Inflammation; Interleukin 1 Receptor Antagonist Protein; Lacticaseibacillus casei; Male; Mice; Mice, Inbred C57BL; Mucocutaneous Lymph Node Syndrome; Myocarditis; Natriuretic Peptide, Brain; Receptors, Interleukin-1; Vasculitis

Background Sepsis is the overwhelming host response to infection leading to shock and multiple organ dysfunction. Cardiovascular complications greatly increase sepsis-associated mortality. Although murine models are routinely used for preclinical studies, the benefit of using genetically engineered mice in sepsis is countered by discrepancies between human and mouse sepsis pathophysiology. Therefore, recent guidelines have called for standardization of preclinical methods to document organ dysfunction. We investigated the course of cardiac dysfunction and myocardial load in different mouse models of sepsis to identify the optimal measurements for early systolic and diastolic dysfunction. Methods and Results We performed speckle-tracking echocardiography and assessed blood pressure, plasma inflammatory cytokines, lactate, B-type natriuretic peptide, and survival in mouse models of endotoxemia or polymicrobial infection (cecal ligation and puncture, [ CLP ]) of moderate and high severity. We observed that myocardial strain and cardiac output were consistently impaired early in both sepsis models. Suppression of cardiac output was associated with systolic dysfunction in endotoxemia or combined systolic dysfunction and reduced preload in the CLP model. We found that cardiac output at 2 hours post- CLP is a negative prognostic indicator with high sensitivity and specificity that predicts mortality at 48 hours. Using a known antibiotic (ertapenem) treatment, we confirmed that this approach can document recovery. Conclusions We propose a non-invasive approach for assessment of cardiac function in sepsis and myocardial strain and strain rate as preferable measures for monitoring cardiovascular function in sepsis mouse models. We further show that the magnitude of cardiac output suppression 2 hours post- CLP can be used to predict mortality.

Topics: Animals; Biomarkers; Cardiac Output; Cardiomyopathies; Cytokines; Disease Models, Animal; Disease Progression; Echocardiography, Doppler; Inflammation Mediators; Lactic Acid; Male; Mice, Inbred C57BL; Myocardial Contraction; Natriuretic Peptide, Brain; Predictive Value of Tests; Risk Factors; Sepsis; Time Factors; Ventricular Function, Left

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

Chronic BNP therapy prevents atrial electrical remodeling in AF. Inhibition of CaMKII activation plays an important role to its anti-AF efficacy in this model.

Topics: Action Potentials; Animals; Anti-Arrhythmia Agents; Atrial Fibrillation; Atrial Remodeling; Calcium Channels, L-Type; Calcium-Binding Proteins; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Cell Line; Disease Models, Animal; Heart Atria; Heart Rate; Mice; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phosphorylation; Potassium Channels, Inwardly Rectifying; Rabbits; Ryanodine Receptor Calcium Release Channel; Shal Potassium Channels

We recently showed that ticagrelor reduced myocardial ischemia-reperfusion injury (IRI) and downregulated galectin-3 in the ischemic myocardium. This study tested the hypothesis that ticagrelor could reduce IRI through the NF-κB pathway. Rats were randomly divided into sham-operated group, placebo group (gastric administration of saline after IRI), ticagrelor group (gastric administration of ticagrelor after left anterior descending artery ligation), dextran sodium sulfate (DSS) group (DSS was added to drinking water 7 days before IRI), and DSS + ticagrelor group (DSS was added to drinking water 7 days before IRI and gastric administration of ticagrelor after left anterior descending artery ligation). Ticagrelor significantly reduced the infarct size and plasma cTnI at 3 and 7 days after IRI, significantly downregulated protein and mRNA expressions of NF-κB and galectin-3, and mRNA expressions of IL-6 and TNF-α in the ischemic area at 24 hours, 3 and 7 days after IRI. Ticagrelor also significantly decreased plasma high-sensitivity C-reactive protein and NT-proBNP levels at 24 hours and 3 days after IRI. Furthermore, pretreatment with DSS blocked the beneficial effects of ticagrelor. Our study indicates that the cardioprotective effect of ticagrelor might be partly mediated by inhibiting the NF-κB pathway in this rat model of IRI.

Topics: Animals; Anti-Inflammatory Agents; C-Reactive Protein; Disease Models, Animal; Galectin 3; Interleukin-6; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Natriuretic Peptide, Brain; NF-kappa B; Peptide Fragments; Rats, Sprague-Dawley; Signal Transduction; Ticagrelor; Troponin I; Tumor Necrosis Factor-alpha

To investigate the effects of Shenqi Yangxin decoction (SQYXD) on heart function in a rat model of dilated cardiomyopathy (DCM) and its potential mechanisms.. Sprague-Dawley rats were randomly divided into normal (10 rats) and DCM (150 rats) groups. DCM was induced by an intraperitoneal injection of adriamycin. Then, DCM baseline group was randomly selected sixteen DCM rats. The remaining DCM rats were randomly divided into DCM control, perindopril, metoprolol, and SQYXD groups. Cardiac function and histological analysis plus biochemical measurement of serum levels of brain natriuretic peptide (BNP), and inflammatory factors were measured. The mRNA and protein expression levels of high-mobility group box 1 (HMGB1), Toll-like receptor 4 (TLR-4), receptor for advanced glycation end products (RAGE), and nuclear factor-¦ÊB (NF-¦ÊB) were determined. Myocardial metabolism imaging was performed on the normal, SQYXD and DCM control groups to evaluate the effectiveness of treatments.. Rats in the DCM control group exhibited dilated left ventricular diameter, impaired cardiac function, disorganized sarcomere, impaired glucose metabolism, increased heart weight index, and increased levels of BNP, which were improved by treatment with SQYXD. In addition, hearts from rats in the DCM baseline group exhibited significantly higher levels of HMGB1, TLR-4, RAGE, NF-κB, tumor necrosis factor-α, interleukin-1, interleukin-6, interleukin-10, compared with the normal group. Interestingly, the mRNA level of HMGB1 in the DCM baseline group was positively correlated with that of TLR-4, RAGE, NF-κB, BNP, and LVEDD, but negatively correlated with LVEF. SQYXD inhibited the upregulation of HMGB1 expression and its downstream inflammatory factors.. Shenqi Yangxin decoction effectively reduced the dilated left ventricular diameter and improved heart function in dilated cardiomyopathy. The mechanisms underlying the action on DCM involve regulating the gene and protein expression of HMGB1 and its inflammatory signal pathways in the DCM rat model.

Topics: Animals; Cardiomyopathy, Dilated; Disease Models, Animal; Drugs, Chinese Herbal; HMGB1 Protein; Humans; Male; Natriuretic Peptide, Brain; NF-kappa B; Rats; Rats, Sprague-Dawley; Receptor for Advanced Glycation End Products; Toll-Like Receptor 4

Myocardial infarction (MI) remains the most common cause of heart failure (HF) worldwide. For almost 50 years, HF has been recognized as a determinant of adverse prognosis after MI, but efforts to promote myocardial repair have failed to be translated into clinical therapies.. In this study, we investigated the effects of BRD4 on cardiac function and the underlying mechanism.. The in vivo rat model of AMI and in vitro neonatal cardiomyocytes were established and cultured respectively, the BRD4 and NPPA/NPPB expression levels were detected by qPCR and Western blot, and interaction of BRD4 with acetylation RelA or NPPA/B promoters were examined by co-immunoprecipitation and chromatin immunoprecipitation assays, respectively.. We found that BRD4 protein expression was significantly increased in cardiomyocytes of MI rat model and cardiomyocytes under hypoxia, accompanied by the expression of natriuretic peptide A (NPPA) and natriuretic peptide B (NPPB). Functionally, knockdown of BRD4 greatly downregulated the NPPA and NPPB in vivo and in vitro, improved the hemodynamic and biometric parameters in rat with heart failure, as well as decreased the apoptosis occurrence. In vitro studies further demonstrated that BRD4 bound with acetylated RelA to enhance the activation of NF-κb signaling, which resulted in activation of NPPA and NPPB transcriptions.. Taken together, our findings suggest that inhibition of BRD4 attenuated cardiomyocyte apoptosis via NF-κB pathway in myocardial infarction, and this study sheds light on developing new strategies to overcome myocardial damage.

Topics: Acetylation; Animals; Animals, Newborn; Apoptosis; Atrial Natriuretic Factor; Cell Hypoxia; Cells, Cultured; Cellular Microenvironment; Disease Models, Animal; Female; Myocardial Infarction; Myocytes, Cardiac; Natriuretic Peptide, Brain; NF-kappa B; Nuclear Proteins; Promoter Regions, Genetic; Rats, Sprague-Dawley; RNA Interference; RNAi Therapeutics; Signal Transduction; Transcription Factor RelA; Transcription Factors

Mechanical ventilation (MV) is routinely used in pediatric general anesthesia and critical care, but may adversely affect the cardiocirculatory system. Biomarkers are increasingly measured to assess cardiovascular status and improve clinical treatment decision-making. As the impact of mechanical ventilation strategies on cardiovascular biomarkers in ventilated infants is largely unknown, we conducted this retrospective study in a healthy in vivo infant rat ventilation model using 14-days old Wistar rats. We hypothesized that 2 h of mechanical ventilation with high and low positive end-expiratory pressure (PEEP), hyperoxemia, hypoxemia, hypercapnia, and hypocapnia would significantly impact B-type natriuretic peptide (BNP), vascular endothelial growth factor (VEGF), and endothelin-1 (ET-1). We found BNP to be driven by both high (9 cmH

Topics: Animals; Animals, Newborn; Biomarkers; Disease Models, Animal; Endothelin-1; Female; Male; Natriuretic Peptide, Brain; Rats; Rats, Wistar; Respiration, Artificial; Vascular Endothelial Growth Factor A

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

Diabetes mellitus (DM) has been demonstrated to have a strong association with heart failure. Conventional echocardiographic analysis cannot sensitively monitor cardiac dysfunction in type I diabetic Akita hearts, but the phenotype of heart failure is observed in molecular levels during the early stages.. Male Akita (Ins2WT/C96Y) mice were monitored with echocardiographic imaging at various ages, and then with conventional echocardiographic analysis and speckle-tracking based strain analyses.. With speckle-tracking based strain analyses, diabetic Akita mice showed changes in average global radial strain at the age of 12 weeks, as well as decreased longitudinal strain. These changes occurred in the early stage and remained throughout the progression of diabetic cardiomyopathy in Akita mice. Speckle-tracking showed that the detailed and precise changes of cardiac deformation in the progression of diabetic cardiomyopathy in the genetic type I diabetic Akita mice were uncoupled.. We monitored early-stage changes in the heart of diabetic Akita mice. We utilize this technique to elucidate the underlying mechanism for heart failure in Akita genetic type I diabetic mice. It will further advance the assessment of cardiac abnormalities, as well as the discovery of new drug treatments using Akita genetic type I diabetic mice.

Topics: Animals; Atrial Natriuretic Factor; Blood Glucose; Body Weight; Diabetes Mellitus, Type 1; Diabetic Cardiomyopathies; Disease Models, Animal; Echocardiography; Female; Heart; Heart Rate; Heart Ventricles; Male; Mice; Mice, Inbred C57BL; Myocardium; Natriuretic Peptide, Brain; Severity of Illness Index; Ventricular Dysfunction, Left

Myocardial apoptosis is important in the pathogenesis and progression of myocardial infarction-induced heart failure (MI-HF). Renal sympathetic denervation (RDN) has become a promising therapeutic strategy for the treatment of HF. Previous studies have shown that RDN could improve heart function Yao et al. (Exp Ther Med 14:4104-4110, 2017). However, whether and how RDN regulates myocardial apoptosis in MI-HF is unclear. This study sought to evaluate the effects of RDN on cardiac function and apoptosis-related gene expression in MI-HF dogs.. Eighteen healthy mongrel dogs were randomly divided into control group(n = 6), model group(n = 6) and treatment group(n = 6). MI-HF was established in model group and treatment group by anhydrous alcohol embolization, after heart failure dogs in the treatment group and model group proceeded bilateral renal artery ablation and bilateral renal arteriography, respectively. The cardiac function parameters were evaluated by echocardiographic; the serum NT-BNP level was detected by ELISA; the degree of myocardial fibrosis was observed through masson staining; the expression of MMP-2, MMP-9 in the cardiac were got by immunohistochemistry. TUNEL method was used to observe cardiomyocyte apoptotsis and calculate the apoptosis index (AI). Relative expression of Bcl-2 and Bax, Caspase3 and GRP78 were detected using RT-PCR and Western Blot. Renal artery H&E staining and serum creatinine were conducted to access the efficacy and safety of RDN.. Four weeks after RDN, the LVEDD, LVESD and LVEDP decreased, and the LVEF and LVSP increased in the treatment group compared with those in the control group (all P < 0.05). Moreover, NT-BNP, an indicator of cardiac function was decreased. Additionally, MMP-2 and MMP-9 levels in the myocardium decreased significantly in the treatment group. Furthermore, the levels of Bax, and caspase 3 decreased, while the level of Bcl-2 increased. Thus, myocardial apoptosis was attenuated in RDN treated dogs. We also found that the level of GRP78 which is activated in response to endoplasmic reticulum (ER) stress, was decreased. However, serum creatinine levels were not significantly different between the RND-treated dogs and the control dogs.. Cardiac function was improved by RDN treatment through regulating apoptosis and ER stress in cardiomyocytes in dogs after MI.

Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Autonomic Denervation; Creatinine; Disease Models, Animal; Dogs; Endoplasmic Reticulum Stress; Female; Fibrosis; Heart Failure; Kidney; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Myocardial Infarction; Myocytes, Cardiac; Natriuretic Peptide, Brain; Peptide Fragments; Recovery of Function; Renal Artery; Stroke Volume; Ventricular Function, Left; Ventricular Pressure

Agonists of peroxisome proliferator-activated receptor gamma (Pparγ) have been demonstrated to reduce the risk of myocardial infarction (MI) in clinical trials and animal experiments. However, the cellular and molecular mechanisms are not completely understood. We aimed to reveal the functions of myeloid Pparγ in MI and explore the potential mechanisms in this study.. Myeloid Pparγ knockout (MPGKO) mice (n = 12) and control mice (n = 8) underwent coronary artery ligation to induce MI. Another cohort of MPGKO mice and control mice underwent coronary artery ligation and were then treated with IgG or neutralizing antibodies against interleukin (IL)-1β. Infarct size was determined by TTC staining and cardiac function was measured using echocardiography. Conditioned media from GW9662- or vehicle-treated macrophages were used to treat H9C2 cardiomyocyte cell line. Gene expression was analyzed using quantitative PCR. Reactive oxygen species were measured using flow cytometry.. Myeloid Pparγ deficiency significantly increased myocardial infarct size. Cardiac hypertrophy was also exacerbated in MPGKO mice, with upregulation of β-myosin heavy chain (Mhc) and brain natriuretic peptide (Bnp) and downregulation of α-Mhc in the non-infarcted zone. Conditioned media from GW9662-treated macrophages increased expression of β-Mhc and Bnp in H9C2 cells. Echocardiographic measurements showed that MPGKO mice had worsen cardiac dysfunction after MI. Myeloid Pparγ deficiency increased gene expression of NADPH oxidase subunits (Nox2 and Nox4) in the non-infarcted zone after MI. Conditioned media from GW9662-treated macrophages increased reactive oxygen species in H9C2 cells. Expression of inflammatory genes such as IL-1β and IL-6 was upregulated in the non-infarcted zone of MPGKO mice after MI. With the injection of neutralizing antibodies against IL-1β, control mice and MPGKO mice had comparable cardiac function and expression of inflammatory genes after MI.. Myeloid Pparγ deficiency exacerbates MI, likely through increased oxidative stress and cardiac inflammation.

Topics: Animals; Cell Line; Disease Models, Animal; Disease Progression; Genetic Predisposition to Disease; Hypertrophy, Left Ventricular; Interleukin-1beta; Macrophages, Peritoneal; Mice, Knockout; Myocardial Infarction; Myocytes, Cardiac; Myosin Heavy Chains; NADPH Oxidase 2; NADPH Oxidase 4; Natriuretic Peptide, Brain; Oxidative Stress; Phenotype; PPAR gamma; Signal Transduction; Time Factors; Ventricular Function, Left; Ventricular Remodeling

The purpose of this study was to evaluate the cardiac electrophysiologic effects of targeted ablation of cardiac sympathetic neurons (TACSN) in a canine model of chronic myocardial infarction (MI).. Thirty-eight anaesthetized dogs were randomly assigned into the sham-operated, MI, and MI-TACSN groups, respectively. Myocardial infarction-targeted ablation of cardiac sympathetic neuron was induced by injecting cholera toxin B subunit-saporin compound in the left stellate ganglion (LSG). Five weeks after surgery, the cardiac function, heart rate variability (HRV), ventricular electrophysiological parameters, LSG function and neural activity, serum norepinephrine (NE), nerve growth factor (NGF), and brain natriuretic peptide (BNP) levels were measured. Cardiac sympathetic innervation was determined with immunofluorescence staining of growth associated protein-43 (GAP43) and tyrosine hydroxylase (TH). Compared with MI group, TACSN significantly improved HRV, attenuated LSG function and activity, prolonged corrected QT interval, decreased Tpeak-Tend interval, prolonged ventricular effective refractory period (ERP), and action potential duration (APD), decreased the slopes of APD restitution curves, suppressed the APD alternans, increased ventricular fibrillation threshold, and reduced serum NE, NGF, and BNP levels. Moreover, the densities of GAP43 and TH-positive nerve fibres in the infarcted border zone in the MI-TACSN group were lower than those in the MI group.. Targeted ablation of cardiac sympathetic neuron attenuates sympathetic remodelling and improves ventricular electrical remodelling in the chronic phase of MI. These data suggest that TACSN may be a novel approach to treating ventricular arrhythmias.

Topics: Action Potentials; Animals; Biomarkers; Cholera Toxin; Disease Models, Animal; Dogs; Electrophysiologic Techniques, Cardiac; Heart; Heart Rate; Myocardial Infarction; Natriuretic Peptide, Brain; Nerve Growth Factor; Norepinephrine; Recovery of Function; Saporins; Stellate Ganglion; Sympathectomy, Chemical; Time Factors; Ventricular Function, Left; Ventricular Remodeling

Preeclampsia is one of the most frequent and difficult illnesses in pregnancy, which jeopardizes both mother and fetus. There are several diagnostic criteria for preeclampsia. However, the preeclampsia-associated myocardial damage has not been described. In this study, we employed reduced uterine perfusion pressure (RUPP) to generate a rat model of preeclampsia for the evaluation of myocardial damage in late-gestation rats. The expressions of cardiac injury markers were analyzed by immunohistochemistry and ELISA. The arterial pressure and myocardial tissue velocities were also measured. The role of interleukin (IL)-6 in RUPP-associated myocardial damage was further explored. The results showed that RUPP rats had significant myocardial damage, as demonstrated by the high expressions of myoglobin, creatine kinase isoenzyme, cardiac troponin I, and brain natriuretic peptide. In addition, RUPP increased the mean arterial pressure and the early transmitral flow velocity to mitral annulus early diastolic velocity ratio (E/Ea). Furthermore, IL-6 deteriorated these abnormalities, whereas inhibition of IL-6 significantly relieved them. In conclusion, our study demonstrated that RUPP rats displayed myocardial damage in an IL-6-dependent manner.

Topics: Animals; Antibodies, Monoclonal, Humanized; Arterial Pressure; Cardiomyopathies; Creatine Kinase, MB Form; Disease Models, Animal; Echocardiography, Doppler, Color; Female; Heart; Interleukin-6; Myocardium; Myoglobin; Natriuretic Peptide, Brain; Perfusion; Pre-Eclampsia; Pregnancy; Random Allocation; Rats, Sprague-Dawley; Troponin I

Preeclampsia is a hypertensive disorder of pregnancy known to increase the risk of cardiovascular disease in mothers and offspring. Offspring exposed to a suboptimal intrauterine environment may experience altered fetal programming and subsequent long-term cardiovascular changes. This study investigated changes in the vascular response in offspring from experimental preeclampsia (EPE) induced by uterine artery ligation, in the absence of fetal growth restriction, compared to normal baboon pregnancies (controls), following a high salt diet challenge. After 1 week of standard diet (containing <1% salt), animals were fed a high salt diet (6%) for 2 weeks. Systolic and diastolic blood pressure (SBP, DBP), aldosterone, renin and creatinine clearance were evaluated in EPE (n = 6, 50% male) and control (n = 6, 50% male) offspring. A repeated measures analysis was performed, and P < 0.05 was considered significant. At baseline, there were no differences between the groups in any parameter (EPE, mean age and weight 3.2 ± 1.2 years, 6.8 ± 1.0 kg, respectively; Control, 2.9 ± 0.8 years, 7.1 ± 1.5 kg). After salt loading the EPE group had significantly higher SBP (92 ± 5 mm Hg) compared to the control group (83 ± 4 mm Hg, P = 0.03). Aldosterone concentration was higher in the EPE group despite the same salt excretion and no difference in renal function. Salt sensitivity may differ in offspring from hypertensive pregnancies due to fetal programming. This could have long-term consequences for cardiovascular health of EPE offspring and further research is required to determine the exact pathological mechanisms.

Topics: Animals; Blood Vessels; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Fetus; Hemodynamics; Natriuretic Peptide, Brain; Papio hamadryas; Pre-Eclampsia; Pregnancy; Sodium Chloride, Dietary

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

The cardiac hormones atrial (ANP) and B-type natriuretic peptides (BNP) moderate arterial blood pressure and improve energy metabolism as well as insulin sensitivity via their shared cGMP-producing guanylyl cyclase-A (GC-A) receptor. Obesity is associated with impaired NP/GC-A/cGMP signaling, which possibly contributes to the development of type 2 diabetes and its cardiometabolic complications. In vitro, synthetic ANP, via GC-A, stimulates glucose-dependent insulin release from cultured pancreatic islets and β-cell proliferation. However, the relevance for systemic glucose homeostasis in vivo is not known. To dissect whether the endogenous cardiac hormones modulate the secretory function and/or proliferation of β-cells under (patho)physiological conditions in vivo, here we generated a novel genetic mouse model with selective disruption of the GC-A receptor in β-cells.. Mice with a floxed GC-A gene were bred to Rip-Cre. In vitro, the insulinotropic and proliferative actions of ANP were abolished in islets isolated from β GC-A KO mice. Concordantly, in vivo, infusion of BNP mildly enhanced baseline plasma insulin levels and glucose-induced insulin secretion in control mice. This effect of exogenous BNP was abolished in β GC-A KO mice, corroborating the efficient inactivation of the GC-A receptor in β-cells. Despite this under physiological, ND conditions, fasted and fed insulin levels, glucose-induced insulin secretion, glucose tolerance and β-cell morphology were similar in β GC-A KO mice and control littermates. However, HFD-fed β GC-A KO animals had accelerated glucose intolerance and diminished adaptative β-cell proliferation.. Our studies of β GC-A KO mice demonstrate that the cardiac hormones ANP and BNP do not modulate β-cell's growth and secretory functions under physiological, normal dietary conditions. However, endogenous NP/GC-A signaling improves the initial adaptative response of β-cells to HFD-induced obesity. Impaired β-cell NP/GC-A signaling in obese individuals might contribute to the development of type 2 diabetes.

Topics: Animals; Atrial Natriuretic Factor; Blood Glucose; Cell Proliferation; Disease Models, Animal; Disease Progression; Gene Deletion; Genetic Predisposition to Disease; Glucose Intolerance; Insulin; Insulin-Secreting Cells; Mice, Knockout; Natriuretic Peptide, Brain; Obesity; Phenotype; Receptors, Atrial Natriuretic Factor; Signal Transduction; Tissue Culture Techniques

Several studies propose that (-)-epicatechin, a flavonol present in high concentration in the cocoa, has cardioprotective effects. This study aimed to evaluate the impact of (-)-epicatechin on the development of dilated cardiomyopathy in a δ sarcoglycan null mouse model.. δ Sarcoglycan null mice were treated for 15 days with (-)-epicatechin. Histological and morphometric analysis of the hearts treated mutant mice showed significant reduction of the vasoconstrictions in the coronary arteries as well as fewer areas with fibrosis and a reduction in the loss of the ventricular wall. On the contrary, it was observed a thickening of this region. By Western blot analysis, it was shown, and increment in the phosphorylation level of eNOS and PI3K/AKT/mTOR/p70S6K proteins in the heart of the (-)-epicatechin treated animals. On the other hand, we observed a significantly decreased level of the atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) heart failure markers.. All the results indicate that (-)-epicatechin has the potential to prevent the development of dilated cardiomyopathy of genetic origin and encourages the use of this flavonol as a pharmacological therapy for dilated cardiomyopathy and heart failure diseases.

Topics: Animals; Atrial Natriuretic Factor; Cardiomyopathy, Dilated; Catechin; Coronary Vessels; Disease Models, Animal; Fibrosis; Male; Mice, Knockout; Myocytes, Cardiac; Natriuretic Peptide, Brain; Nitric Oxide Synthase Type III; Phosphatidylinositol 3-Kinase; Phosphorylation; Proto-Oncogene Proteins c-akt; Ribosomal Protein S6 Kinases, 70-kDa; Sarcoglycans; Signal Transduction; TOR Serine-Threonine Kinases; Vasoconstriction; Ventricular Function, Left; Ventricular Remodeling

Polycystic kidney disease (PKD) involves progressive hepatorenal cyst expansion and fibrosis, frequently leading to end-stage renal disease. Increased vasopressin and cAMP signaling, dysregulated calcium homeostasis, and hypertension play major roles in PKD progression. The guanylyl cyclase A agonist, B-type natriuretic peptide (BNP), stimulates cGMP and shows anti-fibrotic, anti-hypertensive, and vasopressin-suppressive effects, potentially counteracting PKD pathogenesis. Here, we assessed the impacts of guanylyl cyclase A activation on PKD progression in a rat model of PKD. Sustained BNP production significantly reduced kidney weight, renal cystic indexes and fibrosis, in concert with suppressed hepatic cystogenesis in vivo. In vitro, BNP decreased cystic epithelial cell proliferation, suppressed fibrotic gene expression, and increased intracellular calcium. Together, our data demonstrate multifaceted effects of sustained activation of guanylyl cyclase A on polycystic kidney and liver disease. Thus, targeting the guanylyl cyclase A-cGMP axis may provide a novel therapeutic strategy for hepatorenal fibrocystic diseases.

Topics: Animals; Cell Proliferation; Cyclic AMP; Cyclic GMP; Cysts; Disease Models, Animal; Disease Progression; Epithelial Cells; Female; Fibrosis; Genetic Vectors; Humans; Hypertension; Kidney; Liver; Liver Diseases; Male; Natriuretic Peptide, Brain; Parvovirinae; Polycystic Kidney, Autosomal Recessive; Rats; Rats, Sprague-Dawley; Receptors, Atrial Natriuretic Factor; Signal Transduction; Vasopressins

Topics: Amyloid; Amyloid Neuropathies, Familial; Animals; Biomarkers; Cardiomyopathies; Collagen Type IV; Disease Models, Animal; Doxycycline; Drug Administration Schedule; Drug Therapy, Combination; Gene Expression; Heart; Heat Shock Transcription Factors; Humans; Male; Mice; Mice, Transgenic; Mutation; Natriuretic Peptide, Brain; Peptide Fragments; Prealbumin; Ursodeoxycholic Acid

Apelin, an endogenous ligand for apelin receptor (APJ), is reported to be involved in cardiomyocyte hypertrophy. In this study, we explored the mechanism of cardiomyocyte hypertrophy induced by apelin-13/APJ system. Left ventricular hypertrophy (LVH) rat model was established by constricting the abdominal aorta. Western blots were used for protein expression in LVH rats and cultured H9c2 cardiomyocytes. Transmission electron microscopy (TEM) was used to monitor morphological features of cells. In addition, the diameter and volume of H9c2 cells were detected by Scepter™ Handheld Automated Cell Counter. We found that the APJ was increased, but caveolin-1 was decreased in heart of LVH rats. In addition, caveolin-1 was suppressed by apelin-13, and this effect was reversed by APJ antagonist F13A in cultured H9c2 cardiomyocytes. Apelin-13 not only stimulated the formation of autophagolysosomes, autophagosome, and lysosomes but also increased the expression of autophagic markers Beclin-1 and LC3II/I. Besides, the increase of Beclin-1 and LC3 II/I was reversed by F13A or caveolin-1 overexpression and further enhanced by caveolin inhibitor. Furthermore, the cardiomyocyte hypertrophy index brain natriuretic peptide (BNP) induced by apelin-13 was blunt by F13A or autophagy inhibitor 3-methyladenine and further promoted by caveolin inhibitor. And caveolin-1 overexpression reduced the diameter and volume of H9c2 cells induced by apelin-13. Our study indicates that caveolin-1-autophagy pathway mediated cardiomyocyte hypertrophy induced by apelin-13/APJ system, which might provide a novel therapeutic target for cardiac hypertrophy disease.

Topics: Adenine; Animals; Aorta, Abdominal; Apelin Receptors; Autophagosomes; Autophagy; Beclin-1; Caveolin 1; Cell Line; Disease Models, Animal; Hypertrophy, Left Ventricular; Intercellular Signaling Peptides and Proteins; Microtubule-Associated Proteins; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phosphatidylinositol 3-Kinases; Rats; Rats, Sprague-Dawley; Receptors, G-Protein-Coupled

Natriuretic peptides have been proposed as biomarkers of cardiovascular disease, especially heart failure. Brain natriuretic peptide (BNP) has also been shown to be upregulated at the transcriptional and translational levels by pro-inflammatory cytokines in cardiac myocytes. Although we often measure plasma BNP levels in cancer patients, it remains unknown whether cancer-related inflammation affects the plasma BNP levels. We investigated the relationship between the BNP and human cancers.. We retrospectively studied 2,923 patients in whom the plasma BNP levels and serum C-reactive protein (CRP) were measured and echocardiography was performed. Patients with clinically evident heart failure (NYHA II or higher), heart disease requiring medical treatment or surgery, renal dysfunction, and inflammatory disease were excluded. There were 234 patients in the final analysis. Blood sampling was performed before surgery and chemotherapy. In addition, we evaluated the relationship between the inflammation and plasma BNP levels in mouse models of colon cancer.. Of the 234 patients, 80 were diagnosed with cancer. Both the plasma BNP and serum CRP levels were significantly higher in cancer patients than those without. There were no significant differences in the echocardiographic parameters. There was a significant positive correlation between the plasma BNP and serum CRP levels in cancer patients (r = 0.360, P<0.01) but not in those without. In cancer patients, only the CRP correlated with the BNP independent of the age, creatinine level, hypertension, and body mass index. In addition, in nude mice with subcutaneous colon cancer, the plasma BNP level was elevated compared with that in non-cancer mice, and there was a significant relationship between the plasma BNP and serum levels of the inflammatory markers.. In cancer patients, as well as colon cancer model mice, the plasma BNP levels were elevated, possibly due to cancer-related inflammation. The effect of cancer on the BNP levels should be considered when using BNP as an indicator of heart failure in cancer patients.

Topics: Animals; Body Mass Index; C-Reactive Protein; Creatinine; Disease Models, Animal; Female; Humans; Mice; Natriuretic Peptide, Brain; Neoplasms; Regression Analysis; Retrospective Studies

Persistent pulmonary hypertension of the newborn (PPHN) is a life‑threatening disease that is commonly observed in the neonatal intensive care unit. PPHN is pathologically characterized by pulmonary vascular remodeling and, in particular, pulmonary artery smooth muscle cell (PASMC) proliferation. Decreased expression levels of peroxisome proliferator‑activated receptor γ (PPAR‑γ), which is a member of the nuclear receptor hormone superfamily, in combination with elevated expressions of transient receptor potential cation channel, subfamily C, member 1 (TRPC1) and TRPC6 contributes to the PASMC proliferation and excessive pulmonary vascular remodeling in adult pulmonary hypertension (PH). Whether PPAR‑γ, TRPC1 and TRPC6 affect the development of vascular remodeling in PPHN model rats remains unknown. The aim of the present study was to investigate the roles of PPAR‑γ, TRPC1 and TRP6 on the pathogenesis of PPHN in rats. The rat model of PPHN was established by exposure to hypoxic conditions and indomethacin treatment. Lung tissues, hearts and blood from PPHN model and Control rats were collected and examined. Parameters, including the percentage of medial wall thickness (WT %), the percentage of medial wall area (WA %), right ventricular hypertrophy (RVH) and the plasma concentration of B‑type natriuretic peptide (BNP) were used to estimate the development of PPHN. The expression levels of PPAR‑γ, TRPC1 and TRPC6 in lung tissues were detected by immunohistochemistry, western blotting and reverse transcription‑quantitative polymerase chain reaction. Significant increases were observed in the WT %, WA %, RVH and plasma BNP in the PPHN group compare with the Control group (P<0.01). In addition, the mRNA and protein expression levels of PPAR‑γ were markedly downregulated (P<0.05 vs. Control). In the PPHN group, the protein expression levels of TRPC1 and TRPC6 were higher compared to the control group; however, there was no difference in the mRNA expression levels (P>0.05). In conclusion, the present study successfully established a PPHN rat model, and the altered expressions of PPAR‑γ, TRPC1 and TRPC6 in the pulmonary artery located in the lungs of newborn rats with PPHN suggested that these proteins may be important mediators of PPHN.

Topics: Animals; Animals, Newborn; Disease Models, Animal; Female; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Lung; Natriuretic Peptide, Brain; PPAR gamma; Protein Transport; Rats; Rats, Sprague-Dawley; RNA, Messenger; TRPC Cation Channels; Vascular Remodeling

Emerging evidence has suggested that intermedin (IMD), a novel member of the calcitonin gene‑related peptide (CGRP) family, has a wide range of cardioprotective effects. The present study investigated the effects of long‑term administration of IMD on cardiac function and sympathetic neural remodeling in heart failure (HF) rats, and studied potential underlying mechanism. HF was induced in rats by myocardial infarction (MI). Male Sprague Dawley rats were randomly assigned to either saline or IMD (0.6 µg/kg/h) treatment groups for 4 weeks post‑MI. Another group of sham‑operated rats served as controls. Cardiac function was assessed by echocardiography, cardiac catheterization and plasma level of B‑type natriuretic peptide (BNP). Cardiac sympathetic neural remodeling was assessed by immunohistochemistical study of tyrosine hydroxylase (TH) and growth associated protein 43 (GAP43) immunoreactive nerve fibers. The protein expression levels of nerve growth factor (NGF), TH and GAP43 in the ventricular myocardium were studied by western blotting. Ventricular fibrillation threshold (VFT) was determined to evaluate the incidence of ventricular arrhythmia. Oxidative stress was assessed by detecting the activity of superoxide dismutase and the level of malondialdehyde. Compared with rats administrated with saline, IMD significantly improved cardiac function, decreased the plasma BNP level, attenuated sympathetic neural remodeling, increased VFT and suppressed oxidative stress. In conclusion, these results indicated that IMD prevents ventricle remodeling and improves the performance of a failing heart. In addition, IMD attenuated sympathetic neural remodeling and reduced the incidence of ventricular arrhythmia, which may contribute to its anti‑oxidative property. These results implicate IMD as a potential therapeutic agent for the treatment of HF.

Topics: Animals; Disease Models, Animal; GAP-43 Protein; Immunohistochemistry; Male; Malondialdehyde; Myocardial Infarction; Natriuretic Peptide, Brain; Nerve Fibers; Nerve Growth Factor; Oxidative Stress; Peptide Hormones; Rats; Rats, Sprague-Dawley; Superoxide Dismutase; Sympathetic Nervous System; Tyrosine 3-Monooxygenase

Heart failure (HF) is associated with autonomic dysfunction. Vagus nerve stimulation has been shown to improve cardiac function both in HF patients and animal models of HF. The purpose of this present study is to investigate the effects of ganglionated plexus stimulation (GPS) on HF progression and autonomic remodeling in a canine model of acute HF post-myocardial infarction.. Eighteen adult mongrel male dogs were randomized into the control (n=8) and GPS (n=10) groups. All dogs underwent left anterior descending artery ligation followed by 6-hour high-rate (180-220bpm) ventricular pacing to induce acute HF. Transthoracic 2-dimensional echocardiography was performed at different time points. The plasma levels of norepinephrine, B-type natriuretic peptide (BNP) and Ang-II were measured using ELISA kits. C-fos and nerve growth factor (NGF) proteins expressed in the left stellate ganglion as well as GAP43 and TH proteins expressed in the peri-infarct zone were measured using western blot. After 6h of GPS, the left ventricular end-diastolic volume, end-systolic volume and ejection fraction showed no significant differences between the 2 groups, but the interventricular septal thickness at end-systole in the GPS group was significantly higher than that in the control group. The plasma levels of norepinephrine, BNP, Ang-II were increased 1h after myocardial infarction while the increase was attenuated by GPS. The expression of c-fos and NGF proteins in the left stellate ganglion as well as GAP43 and TH proteins in cardiac peri-infarct zone in GPS group were significantly lower than that in control group.. GPS inhibits cardiac sympathetic remodeling and attenuates HF progression in canines with acute HF induced by myocardial infarction and ventricular pacing.

Topics: Angiotensin II; Animals; Biomarkers; Disease Models, Animal; Disease Progression; Dogs; Electric Stimulation Therapy; GAP-43 Protein; Heart; Heart Failure; Male; Myocardial Infarction; Natriuretic Peptide, Brain; Nerve Growth Factor; Norepinephrine; Parasympathetic Nervous System; Proto-Oncogene Proteins c-fos; Random Allocation; Tyrosine 3-Monooxygenase

Cholecystokinin (CCK) is expressed in cardiomyocytes and may also play an important role in cardiovascular regulation. Clinical studies have shown that plasma CCK levels are an independent marker of cardiovascular mortality in cardiac disease. However, whether the development of postinfarction heart failure is associated with changes in CCK expression is unknown.. To investigate CCK expression patterns and the association between CCK expression and heart functional parameters, we randomized male Sprague-Dawley rats into myocardial infarction (MI) or sham operation (SO) groups. CCK expression levels were assessed by western blotting, immunohistochemistry, real-time polymerase chain reaction (PCR), and enzyme-linked immunosorbent assay (ELISA) at different time points (2, 4 or 6 weeks) after surgery. Brain natriuretic peptide (BNP) concentrations were determined using Western blotting and ELISA, myocardial morphology was assessed by microscopy.. Plasma CCK and BNP levels were significantly increased in all the MI groups compared with the corresponding SO groups. However, the degree to which myocardial CCK mRNA and protein expression levels were increased the MI groups compared with the SO groups was greater in the 4- and 6-week groups than in the 2-week group. Furthermore, plasma CCK levels were positively correlated with BNP concentrations and left ventricular end-systolic diameter (LVDs) and significantly negatively correlated with the ejection fraction (EF) and shortening fraction (SF) in model animals.. Heart failure progression after infarction is associated with upregulated CCK levels; thus, CCK may be useful as a novel marker of heart failure.

Topics: Animals; Biomarkers; Body Weight; Cholecystokinin; Disease Models, Animal; Echocardiography; Enzyme-Linked Immunosorbent Assay; Fibrosis; Heart; Heart Failure; Immunohistochemistry; Male; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction

Besides the relevant role of brain-type natriuretic peptide (BNP) as biomarker of cardioembolic strokes, new experimental evidences suggest that this peptide may mediate neuroprotective effects. In this study, we have evaluated for the first time the clinical association between BNP (by means of proBNP) and good outcome in ischemic stroke patients, and analyzed the effect of blood BNP increase in an ischemic animal model.. A retrospective study with 2 different cohorts (262 patients in cohort I and 610 in cohort II) from the same prospective stroke registry was performed. proBNP concentration was analyzed within the first 12 hours from stroke onset. The primary predictor variable was functional outcome evaluated by modified Rankin Scale at 3 months. For the experimental study, BNP pretreatment was tested in an ischemic animal model subjected to a transient occlusion of the cerebral artery, and the infarct volume and sensorimotor deficit were evaluated for 14 days. Cardioembolic strokes presented a positive correlation between proBNP concentration and modified Rankin Scale at 3 months; however, noncardioembolic strokes presented a negative correlation. In the logistic regression analysis, noncardioembolic strokes with concentrations of proBNP ≥340 pg/mL were associated with a good outcome. In line with these clinical findings, the experimental study revealed that those BNP pretreated animals presented a reduction on infarct volumes at 24 hours and functional recovery at days 7 and 14 compared with the control groups.. These clinical and experimental evidences support the potential role of BNP as a protective factor against cerebral ischemia.

Topics: Animals; Biomarkers; Brain Ischemia; Chi-Square Distribution; Disability Evaluation; Disease Models, Animal; Infarction, Middle Cerebral Artery; Logistic Models; Male; Motor Activity; Natriuretic Peptide, Brain; Neuroprotective Agents; Odds Ratio; Prognosis; Protective Factors; Rats, Sprague-Dawley; Recovery of Function; Registries; Retrospective Studies; Risk Factors; Sensory Thresholds; Stroke; Time Factors

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

An altered IL-18 pathway in heart failure (HF) has recently been described and this cytokine was shown to be of clinical and prognostic utility. Cardiomyocytes are a target of this cytokine which exerts inflammatory, hypertrophic, and profibrotic activities. B-type natriuretic peptide is a cardiac hormone produced in response to cardiac filling to regulate cardiovascular homeostasis. The aim of the study was to verify the ability of IL-18 to induce B-type natriuretic peptide synthesis in vitro and to analyse the relationship between these two molecules in plasma in vivo from acute HF patients.. We demonstrated the ability of IL-18 to directly stimulate a murine cardiomyocyte cell line to express the B-type natriuretic peptide gene, synthesize the relative protein through a PI3K-AKT-dependent transduction, and induce a cell secretory phenotype with B-type natriuretic peptide release. A correlation between IL-18 and B-type natriuretic peptide plasma levels was found in non-overloaded acute HF patients, and in subgroups of acute HF patients with diabetes and coronary artery disease. Acute HF patients with renal failure had significantly higher IL-18 plasma levels than patients without. IL-18 plasma levels were correlated with C-reactive protein plasma levels.. This study provides the first evidence of the ability of IL-18 to induce B-type natriuretic peptide synthesis in vitro and outlines the relationship between the two molecules in acute HF patients with an ongoing inflammatory status.

Topics: Acute Disease; Aged; Aged, 80 and over; Animals; Biomarkers; Cells, Cultured; Disease Models, Animal; Female; Gene Expression Regulation; Heart Failure; Humans; Interleukin-18; Male; Mice; Microscopy, Fluorescence; Middle Aged; Myocytes, Cardiac; Natriuretic Peptide, Brain; Real-Time Polymerase Chain Reaction; RNA, Messenger

Cardiovascular disease is the leading cause of death with high morbidity and mortality, and chronic heart failure is the terminal phase of it. This study aimed to investigate the protective effects of the low-dose rosuvastatin on isoproterenol-induced chronic heart failure and to explore the possible related mechanisms.. Male Sprague Dawley rats were given isoproterenol 5 mg/kg once a day for 7 days to establish heart failure model by subcutaneous injection. Simultaneously, low-dose rosuvastatin (5 mg/kg) was orally administrated from day 1 to day 14. Protective effects were evaluated by hemodynamic parameter, histopathological variables, serum asymmetric dimethylarginine (ADMA), cardiac troponin I (cTnI), brain natriuretic peptide (BNP) and myocardial nitric oxide (NO), and the levels of dimethylarginine dimethylaminohydrolase 2 (DDAH2), arginine methyltransferases 1 (PRMT1) and endothelial nitric oxide synthase (eNOS) expression were analyzed.. Therapeutic rosuvastatin (5 mg/kg) significantly attenuated isoproterenol-induced hypertrophy, remodeling and dysfunction of ventricle, reduced the increased serum content of ADMA, cTnI, and BNP, and elevated myocardial NO in rats (P<.05). Besides, rosuvastatin also significantly inhibited fibrosis of myocardium, normalized the increased PRMT1 and decreased DDAH2 expression.. Low-dose rosuvastatin exerted cardioprotective effects on isoproterenol-induced heart failure in rats by modulating DDAH-ADMA-NO pathway, and it may present the new therapeutic value in ameliorating chronic heart failure.

Topics: Amidohydrolases; Animals; Biomarkers; Cardiotonic Agents; Disease Models, Animal; Fibrosis; Heart Failure; Hypertrophy, Left Ventricular; Isoproterenol; Male; Myocardium; Natriuretic Peptide, Brain; Nitric Oxide; Nitric Oxide Synthase Type III; Protein-Arginine N-Methyltransferases; Rats, Sprague-Dawley; Rosuvastatin Calcium; Troponin I; Ventricular Dysfunction, Left; Ventricular Function, Left; Ventricular Pressure; Ventricular Remodeling

To evaluate the influence of bilateral or left sympathectomy on left ventricular remodeling and function after myocardial infarction in rats.. Myocardial infarction was induced in rats by ligation of the left anterior descending coronary. Seven days later, rats were divided into 4 groups: the myocardial infarction, myocardial infarction with left sympathectomy, myocardial infarction with bilateral sympathectomy, and sham groups. After 8 weeks, left ventricular function was evaluated with the use of a pressure-volume conductance catheter under steady-state conditions and pharmacological stress. Infarct size and extracellular matrix fibrosis were evaluated, and cardiac matrix metalloproteinases and myocardial inflammatory markers were analyzed.. The myocardial infarction and left sympathectomy group had an increased end diastolic volume, whereas the bilateral sympathectomy group had a mean end-diastolic volume similar to that of the sham group (P < .002). Significant reduction in ejection fraction was observed in the myocardial infarction and left sympathectomy group, whereas it was preserved after bilateral sympathectomy (P < .001). In response to dobutamine, left ventricular contractility increased in sham rats, rising stroke work, cardiac output, systolic volume, end-diastolic volume, ejection fraction, and dP/dt max. Only bilateral sympathectomy rats had significant increases in ejection fraction (P < .001) with dobutamine. Fibrotic tissue and matrix metalloproteinase expression decreased in the bilateral sympathectomy group compared to that in the myocardial infarction group (P < .001) and was associated with left ventricular wall thickness maintenance and better apoptotic markers in noninfarcted myocardium.. Bilateral sympathectomy effectively attenuated left ventricular remodeling and preserved systolic function after myocardial infarction induction in rats.

Topics: Animals; Apoptosis; Catecholamines; Cytokines; Disease Models, Animal; Fibrosis; Heart Ventricles; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Myocardial Contraction; Myocardial Infarction; Natriuretic Peptide, Brain; Rats, Wistar; Recovery of Function; Stroke Volume; Sympathectomy; Vascular Endothelial Growth Factor A; Ventricular Function, Left; Ventricular Remodeling

Recent studies have shown that plasma levels of the biologically inactive prohormone for brain natriuretic peptide (proBNP) are increased in patients with heart failure. This can contribute to a reduction in the effectiveness of circulating BNP and exacerbate heart failure progression. The precise mechanisms governing the increase in proBNP remain unclear, however.. We used our recently developed, highly sensitive human proBNP assay system to investigate the mechanisms underlying the increase in plasma proBNP levels. We divided 53 consecutive patients hospitalized with heart failure into 2 groups based on their aortic plasma levels of immunoreactive BNP. Patients with higher levels exhibited more severe heart failure, a higher proportion of proBNP among the immunoreactive BNP forms secreted from failing hearts, and a weaker effect of BNP as estimated from the ratio of plasma cyclic guanosine monophosphate levels to log-transformed plasma BNP levels. Glycosylation at threonines 48 and 71 of human proBNP contributed to the increased secretion of proBNP by attenuating its processing, and GalNAc-transferase (GALNT) 1 and 2 mediated the glycosylation-regulated increase in cardiac human proBNP secretion. Cardiac GALNT1 and 2 expression was suppressed by microRNA (miR)-30, which is abundantly expressed in the myocardium of healthy hearts, but is suppressed in failing hearts.. We have elucidated a novel miR-30-GALNT1/2 axis whose dysregulation increases the proportion of inactive proBNP secreted by the heart and impairs the compensatory actions of BNP during the progression of heart failure.

Topics: Aged; Animals; Animals, Newborn; Aorta, Thoracic; Biomarkers; Blotting, Western; Cells, Cultured; Chromatography, Gel; Disease Models, Animal; Disease Progression; Echocardiography; Female; Follow-Up Studies; Gene Expression Regulation; Glycosylation; Heart Failure; Heart Ventricles; Humans; Male; MicroRNAs; Middle Aged; Myocardium; Myocytes, Cardiac; N-Acetylgalactosaminyltransferases; Natriuretic Peptide, Brain; Peptide Fragments; Polypeptide N-acetylgalactosaminyltransferase; Protein Precursors; Rats; Rats, Inbred Dahl; Real-Time Polymerase Chain Reaction; Retrospective Studies; Signal Transduction

A previous study suggested that activin A inhibited myocardial cell apoptosis. This study thus aimed to explore the effects of the activin A-follistatin system on myocardial cell apoptosis in heart failure (HF) rats in order to determine whether or not the mechanism operates through the endoplasmic reticulum stress (ERS) pathway.. Myocardial infarction (MI) by vascular deprivation was used to induce HF. The enzyme-linked immunosorbent assay was used to detect activin A, follistatin and brain natriuretic peptide (BNP) contents in serum. Immunohistochemical staining for activin A, follistatin, CCAAT-enhancer-binding protein (C/EBP) homologous protein (CHOP) and caspase-3 was performed on the myocardial tissue. The activin A-stimulated apoptosis of H9c2 cells was tested by flow cytometry. Western blot was used to detect the expression levels of activin A, follistatin and ERS-related proteins.. It was found that the high expression of activin A could cause activin A-follistatin system imbalance, inducing myocardial cell apoptosis via ERS in vivo. When HF developed to a certain stage, the expression of follistatin was upregulated to antagonize the expression of activin A. Activin A inhibited cardiomyocyte apoptosis with a low concentration and promoted apoptosis with a high concentration in vitro, also via ERS.. Activin A-follistatin system participated in ERS-mediated myocardial cell apoptosis in HF.

Topics: Activins; Angiotensin II; Animals; Apoptosis; Biomarkers; Caspase 3; Cell Line; Disease Models, Animal; Endoplasmic Reticulum Stress; Female; Follistatin; Heart Failure; Heart Ventricles; Hemodynamics; Immunohistochemistry; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats; Signal Transduction; Transcription Factor CHOP

The efficacy of Chinese herbal formulas in treating Alzheimer has been proved in many studies. In this study, six different Kaixin San formulas were compared to investigate their effects on learning and memory decline, brain-derived neurotrophic factor (BDNF) in the hippocampus, tau protein, acetylcholinesterase (AChE) and N-terminal pro-brain natriuretic peptide (NT-proBNP). Kunming mice were selected and established a mouse model of Alzheimer's by intraperitoneal injection of D-galactose and sodium nitrite, continued intragastric 4 weeks, using the ability of learning and memory in Morris water maze test to evaluate the animals in each group; the content of BDNF in the hippocampus of mice with Western blotting detected; ELISA method for the detection of each group of mice hippocampal tau protein,p-Tau protein, Aβ,Ach,AchE and serum NT-proBNP levels. The results showed that, Kaixin San of Qianjin Yaofang three dose recorded significantly improved learning and memory ability of mice; increased the content of BDNF and Ach in the hippocampus; decreased the content of Aβ, Tau protein, p-Tau protein in the hippocampus; high, middle dose significantly decreased the serum NT-proBNP and AchE in hippocampus, the effect is most significant. Part dose of Kaixin San of Yixin Fang, Kaixin Wan of Yimen Fang, Dingzhi Xiaowan of Beji Qianjin Yaofang and Dingzhi Wan of Guji Luyan could improve the learning and memory ability evaluation indicators, significantly increased BDNF and Ach in the hippocampus of AD model mice, reduced the Aβ, Tau protein, p-Tau protein in hippocampus of AD model mice, decreased the NT-proBNP and AchE in serum of AD mice, the effect is more significant. Three does of Buxin Tang of Qianjin Yi had no effects of treatment in Alzheimer's disease. The results showed the treatment in AD of Kaixin San of Qianjin Yaofang is the most significant.

Topics: Acetylcholinesterase; Alzheimer Disease; Amyloid beta-Peptides; Animals; Disease Models, Animal; Drugs, Chinese Herbal; GPI-Linked Proteins; Hippocampus; Maze Learning; Mice; Natriuretic Peptide, Brain; Peptide Fragments; tau Proteins

In this study, we examined whether aspirin could inhibit cardiac hypertrophy.. We utilized cultured neonatal mouse cardiomyocytes and mice for the study and subjected to cardiomyocyte immunochemistry, qRT-PCR, and immunoblotting analysis. The cardiac function was measured using M-mode echocardiography.. Ten μM aspirin significantly inhibited Ang II-induced increase in cardiomyocyte size, the mRNA, and protein levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and β-myosin heavy chain (β-MHC) (P < 0.05). Meantime, consistent with the result in vitro, the increase in HW/BW ratio, the mRNA, and protein levels of ANP, BNP, and β-MHC could be reduced by aspirin in vivo (P < 0.05). Analysis of cardiac function revealed that mouse hearts treated with Ang II displayed thickening of the ventricular walls, left ventricular end-diastolic dimensions, and left ventricular end-systolic dimensions were significantly decreased (P < 0.05), whereas interventricular septal thickness at end-diastole, interventricular septal thickness at end-systole, posterior wall thickness in diastole, and posterior wall thickness in systole were markedly increased (P < 0.05), which could be reversed by aspirin (P < 0.05). Moreover, aspirin blunted the increase inCa(2+) and inhibited the calcineurin activity and NFAT dephosphorylation caused by Ang II (P < 0.05).. Aspirin inhibited cardiac hypertrophy in vitro and in vivo through inhibition of the Ca(2+)/calcineurin-NFAT signaling pathway. Therefore, these findings suggested that aspirin might become a therapeutic option to reduce cardiac hypertrophy.

Topics: Angiotensin II; Animals; Animals, Newborn; Aspirin; Atrial Natriuretic Factor; Calcineurin; Calcium; Calcium Signaling; Cardiovascular Agents; Cells, Cultured; Disease Models, Animal; Dose-Response Relationship, Drug; Gene Expression Regulation; Hypertrophy, Left Ventricular; Male; Mice; Myocytes, Cardiac; Myosin Heavy Chains; Natriuretic Peptide, Brain; NFATC Transcription Factors; Phosphorylation; Stroke Volume; Ventricular Function, Left

Dilated cardiomyopathy is a major cause of heart failure (HF) that affects millions. Corin cleaves and biologically activates pro-atrial natriuretic peptide (pro-ANP) and pro-B-type natriuretic peptide (pro-BNP). High corin levels reduce the development of systolic dysfunction and HF in experimental dilated cardiomyopathy. Yet, patients with significant HF unexpectedly show low corin levels with high plasma ANP/BNP levels. Therefore, we examined the relationship between cardiac corin expression, ANP/BNP levels, and the stages of HF. We used a well-established, dilated cardiomyopathy model to evaluate gene and protein expression as mice longitudinally developed Stages A-D HF. Cardiac systolic function (ejection fraction) continuously declined over time (P<0.001). Cardiac corin transcripts were decreased at early Stage B HF and remained low through Stages C and D (P<0.001). Cardiac corin levels were positively correlated with systolic function (r=0.96, P=0.003) and inversely with lung water (r=-0.92, P=0.001). In contrast, cardiac pro-ANP/BNP transcripts increased later (Stages C and D) and plasma levels rose only with terminal HF (Stage D, P<0.001). Immunoreactive plasma ANP and BNP levels were positively associated with plasma cyclic guanosine monophosphate levels (r=0.82, P=0.01 and r=0.8, P=0.02, respectively). In experimental dilated cardiomyopathy, corin levels declined early with progressive systolic dysfunction before the development of HF, whereas significant increases in plasma ANP, BNP, and cyclic guanosine monophosphate levels were found only in later stage (C and D) HF. This dyssynchrony in expression of corin versus ANP/BNP may impair cleavage activation of pro-natriuretic peptides, and thereby promote the transition from earlier to later stage HF.

Topics: Animals; Atrial Natriuretic Factor; Disease Models, Animal; Disease Progression; Heart Failure; Male; Mice; Myocardium; Natriuretic Peptide, Brain; Peptide Fragments; Serine Endopeptidases; Systole; Time Factors; Ventricular Dysfunction, Left

Pulmonary arterial hypertension (PAH) is a fatal disease with limited therapeutic options. Pathophysiological changes comprise obliterative vascular remodelling of small pulmonary arteries, elevated mean pulmonary arterial systolic pressure (PASP) due to elevated resistance of pulmonary vasculature, adverse right ventricular remodelling, and heart failure. Recent findings also indicate a role of increased inflammation and insulin resistance underlying the development of PAH. We hypothesized that treatment of this condition with the peroxisome proliferator-activated receptor-γ (PPARγ) activator pioglitazone, known to regulate the expression of different genes addressing insulin resistance, inflammatory changes, and vascular remodelling, could be a beneficial approach. PAH was induced in adult rats by a single subcutaneous injection of monocrotaline (MCT). Pioglitazone was administered for 2 weeks starting 3 weeks after MCT-injection. At day 35, hemodynamics, organ weights, and -indices were measured. We performed morphological and molecular characterization of the pulmonary vasculature, including analysis of the degree of muscularization, proliferation rates, and medial wall thickness of the small pulmonary arteries. Furthermore, markers of cardiac injury, collagen content, and cardiomyocyte size were analyzed. Survival rates were monitored throughout the experimental period. Pioglitazone treatment improved survival, reduced PASP, muscularization of small pulmonary arteries, and medial wall thickness. Further, MCT-induced right ventricular hypertrophy and fibrosis were attenuated. This was accompanied with reduced cardiac expression of brain natriuretic peptide, as well as decreased cardiomyocyte size. Finally, pulmonary macrophage content and osteopontin gene expression were attenuated. Based on the beneficial impact of pioglitazone, activation of PPARγ might be a promising treatment option in PAH.

Topics: Animals; Arterial Pressure; Cardiovascular Agents; Disease Models, Animal; Fibrosis; Heart Ventricles; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Macrophages, Alveolar; Male; Monocrotaline; Myocytes, Cardiac; Natriuretic Peptide, Brain; Osteopontin; Pioglitazone; PPAR gamma; Pulmonary Artery; Rats, Sprague-Dawley; Thiazolidinediones; Vascular Remodeling; Ventricular Function, Right; Ventricular Remodeling

Elamipretide (MTP-131), a novel mitochondria-targeting peptide, was shown to reduce infarct size in animals with myocardial infarction and improve renal function in pigs with acute and chronic kidney injury. This study examined the effects of chronic therapy with elamipretide on left ventricular (LV) and mitochondrial function in dogs with heart failure (HF).. Fourteen dogs with microembolization-induced HF were randomized to 3 months monotherapy with subcutaneous injections of elamipretide (0.5 mg/kg once daily, HF+ELA, n=7) or saline (control, HF-CON, n=7). LV ejection fraction, plasma n-terminal pro-brain natriuretic peptide, tumor necrosis factor-α, and C-reactive protein were measured before (pretreatment) and 3 months after initiating therapy (post-treatment). Mitochondrial respiration, membrane potential (Δψm), maximum rate of ATP synthesis, and ATP/ADP ratio were measured in isolated LV cardiomyocytes obtained at post-treatment. In HF-CON dogs, ejection fraction decreased at post-treatment compared with pretreatment (29 ± 1% versus 31 ± 2%), whereas in HF+ELA dogs, ejection fraction significantly increased at post-treatment compared with pretreatment (36 ± 2% versus 30 ± 2%; P<0.05). In HF-CON, n-terminal pro-brain natriuretic peptide increased by 88 ± 120 pg/mL during follow-up but decreased significantly by 774 ± 85 pg/mL in HF+ELA dogs (P<0.001). Treatment with elamipretide also normalized plasma tumor necrosis factor-α and C-reactive protein and restored mitochondrial state-3 respiration, Δψm, rate of ATP synthesis, and ATP/ADP ratio (ATP/ADP: 0.38 ± 0.04 HF-CON versus 1.16 ± 0.15 HF+ELA; P<0.001).. Long-term therapy with elamipretide improves LV systolic function, normalizes plasma biomarkers, and reverses mitochondrial abnormalities in LV myocardium of dogs with advanced HF. The results support the development of elamipretide for the treatment of HF.

Topics: Animals; Biomarkers; C-Reactive Protein; Disease Models, Animal; Dogs; Energy Metabolism; Heart Failure; Infusions, Intravenous; Injections, Subcutaneous; Membrane Potential, Mitochondrial; Mitochondria, Heart; Myocytes, Cardiac; Natriuretic Peptide, Brain; Oligopeptides; Peptide Fragments; Reactive Oxygen Species; Recovery of Function; Stroke Volume; Time Factors; Tumor Necrosis Factor-alpha; Ventricular Dysfunction, Left; Ventricular Function, Left

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

Sheng-Mai Yin (SMY), a modern Chinese formula based on Traditional Chinese Medicine theory, has been used to treat cardiovascular diseases in Eastern Asia. Our study focuses on the cardioprotection of SMY against doxorubicin (DOX)-induced cardiac toxicity in vivo.. Rats were injected with DOX (2.5 mg/kg) in six injections over a 2-week period. SMY was administrated intragastrically at the dose of 8.35, 16.7 and 33.4 g/kg, or 16.7 g/kg only twice a day concurrently with DOX for the 2-weeks. A series of assays were performed to detect the effects of SMY on: (i) heart weight index (HWI) and left ventricular mass index (LVMI); (ii) cardiac function; (iii) heart tissue morphology; (iv) the contents of carboxy terminal propeptide of procollagen typeI (PICP), amino terminal propeptide of procollagen type III (PШNP), transforming growth factor-β1 (TGF-β1), B-type natriuretic peptide (BNP), monocyte chemoattractant protein-1 (MCP-1), interferon gamma (INF-γ) and interleukin 6 (IL-6) by ELISA; (v) the mRNA levels of TGF-β1 and toll-like receptor-2 (TLR2); and (vi) protein level of TGF-β1.. Rats treated with SMY displayed the reductions of BNP and CK-MB increased by DOX in a dose-dependent manner. Moderate dose of SMY exhibited the correction for the increased HWI, LVMI, and the injured cardiac function, as well as the collagen accumulation. In addition, cardioprotection of SMY against DOX-induced cardiac toxicity was demonstrated by the reduction of myocardial fibrosis, characterized by the suppression of PICP, PШNP and TGF-β1, as well as the anti-inflammation and the regulation for cardiac immune microenvironment, characterized by the inhibition of TLR2, MCP-1, INF-γ and IL-6.. SMY may protect heart function through the restriction of myocardial fibrosis induced by DOX, which suggests the potentially therapeutic effect of SMY on DOX-induced cardiomyopathy.

Topics: Animals; Cardiomyopathies; Cardiotonic Agents; Cardiotoxicity; Creatine Kinase, MB Form; Disease Models, Animal; Doxorubicin; Drug Combinations; Drugs, Chinese Herbal; Heart; Inflammation Mediators; Male; Natriuretic Peptide, Brain; Organ Size; Rats; Rats, Wistar

Expression of miR-154 is upregulated in the diseased heart and was previously shown to be upregulated in the lungs of patients with pulmonary fibrosis. However, the role of miR-154 in a model of sustained pressure overload-induced cardiac hypertrophy and fibrosis had not been assessed. To examine the role of miR-154 in the diseased heart, adult male mice were subjected to transverse aortic constriction for four weeks, and echocardiography was performed to confirm left ventricular hypertrophy and cardiac dysfunction. Mice were then subcutaneously administered a locked nucleic acid antimiR-154 or control over three consecutive days (25 mg/kg/day) and cardiac function was assessed 8 weeks later. Here, we demonstrate that therapeutic inhibition of miR-154 in mice with pathological hypertrophy was able to protect against cardiac dysfunction and attenuate adverse cardiac remodelling. The improved cardiac phenotype was associated with attenuation of heart and cardiomyocyte size, less cardiac fibrosis, lower expression of atrial and B-type natriuretic peptide genes, attenuation of profibrotic markers, and increased expression of p15 (a miR-154 target and cell cycle inhibitor). In summary, this study suggests that miR-154 may represent a novel target for the treatment of cardiac pathologies associated with cardiac fibrosis, hypertrophy and dysfunction.

Topics: Animals; Aorta; Atrial Natriuretic Factor; Cyclin-Dependent Kinase Inhibitor p15; Disease Models, Animal; Echocardiography; Hypertension; Hypertrophy, Left Ventricular; Male; Mice; Mice, Inbred C57BL; MicroRNAs; Natriuretic Peptide, Brain; Oligonucleotides; Pulmonary Fibrosis; Ventricular Remodeling

High ADAMTS-7 levels are associated with acute myocardial infarction (AMI), although its involvement in ventricular remodeling is unclear. In this study, we investigated the association between ADAMTS-7 expression and cardiac function in a rat AMI model.. Sprague-Dawley rats were randomized into AMI (n = 40) and sham (n = 20) groups. The left anterior descending artery was sutured to model AMI. Before surgery and 7, 14, 28, and 42 days post-surgery, ADAMTS-7 and brain natriuretic peptide (BNP), and cartilage oligomeric matrix protein (COMP) were assessed by ELISA, western blot, real-time RT-PCR, and/or immunohistochemistry. Cardiac functional and structural parameters were assessed by M-mode echocardiography.. After AMI, plasma ADAMTS-7 levels increased, peaking on day 28 (AMI: 13.2 ± 6.3 vs. sham: 3.4 ± 1.3 ng/ml, P < 0.05). Compared with the sham group, ADAMTS-7 expression was higher in the infarct zone at day 28. COMP present in normal myocardium was degraded by day 28 post-AMI. Plasma ADAMTS-7 correlated positively with BNP (r = 0.642, P = 0.025), left ventricular end-diastolic diameter (r = 0.695, P = 0.041), left ventricular end-systolic diameter (r = 0.710, P = 0.039), left ventricular ejection fraction (r = 0.695, P = 0.036), and left ventricular short-axis fractional shortening (r = 0.721, P = 0.024).. ADAMTS-7 levels may reflect the degree of ventricular remodeling after AMI.

Topics: ADAMTS7 Protein; Animals; Cartilage Oligomeric Matrix Protein; Disease Models, Animal; Echocardiography; Male; Myocardial Infarction; Natriuretic Peptide, Brain; Random Allocation; Rats; Rats, Sprague-Dawley; Ventricular Function, Left; Ventricular Remodeling

Cyclic guanosine monophosphate-protein kinase G-phosphodiesterase 5 signaling may be disturbed in heart failure (HF) with preserved ejection fraction, contributing to cardiac remodeling and dysfunction. The purpose of this study was to manipulate cyclic guanosine monophosphate signaling using the dipeptidyl-peptidase 4 inhibitor saxagliptin and phosphodiesterase 5 inhibitor tadalafil. We hypothesized that preservation of cyclic guanosine monophosphate cGMP signaling would attenuate pathological cardiac remodeling and improve left ventricular (LV) function.. We assessed LV hypertrophy and function at the organ and cellular level in aortic-banded pigs. Concentric hypertrophy was equal in all groups, but LV collagen deposition was increased in only HF animals. Prevention of fibrotic remodeling by saxagliptin and tadalafil was correlated with neuropeptide Y plasma levels. Saxagliptin better preserved integrated LV systolic and diastolic function by maintaining normal LV chamber volumes and contractility (end-systolic pressure-volume relationship, preload recruitable SW) while preventing changes to early/late diastolic longitudinal strain rate. Function was similar to the HF group in tadalafil-treated animals including increased LV contractility, reduced chamber volume, and decreased longitudinal, circumferential, and radial mechanics. Saxagliptin and tadalafil prevented a negative cardiomyocyte shortening-frequency relationship observed in HF animals. Saxagliptin increased phosphodiesterase 5 activity while tadalafil increased cyclic guanosine monophosphate levels; however, neither drug increased downstream PKG activity. Early mitochondrial dysfunction, evident as decreased calcium-retention capacity and Complex II-dependent respiratory control, was present in both HF and tadalafil-treated animals.. Both saxagliptin and tadalafil prevented increased LV collagen deposition in a manner related to the attenuation of increased plasma neuropeptide Y levels. Saxagliptin appears superior for treating heart failure with preserved ejection fraction, considering its comprehensive effects on integrated LV systolic and diastolic function.

Topics: Adamantane; Animals; Atrial Natriuretic Factor; Cyclic GMP; Dipeptides; Dipeptidyl-Peptidase IV Inhibitors; Disease Models, Animal; Echocardiography; Hypertrophy, Left Ventricular; Male; Natriuretic Peptide, Brain; Neuropeptide Y; Phosphodiesterase 5 Inhibitors; Signal Transduction; Swine; Swine, Miniature; Tadalafil; Ventricular Function, Left

Limited therapies exist for patients with congenital heart disease (CHD) who develop right ventricular (RV) dysfunction. Bone marrow-derived mesenchymal stem cells (MSCs) have not been evaluated in a preclinical model of pressure overload, which simulates the pathophysiology relevant to many forms of CHD. A neonatal swine model of RV pressure overload was utilized to test the hypothesis that MSCs preserve RV function and attenuate ventricular remodeling. Immunosuppressed Yorkshire swine underwent pulmonary artery banding to induce RV dysfunction. After 30 min, human MSCs (1 million cells, n = 5) or placebo (n = 5) were injected intramyocardially into the RV free wall. Serial transthoracic echocardiography monitored RV functional indices including 2D myocardial strain analysis. Four weeks postinjection, the MSC-treated myocardium had a smaller increase in RV end-diastolic area, end-systolic area, and tricuspid vena contracta width (P < 0.01), increased RV fractional area of change, and improved myocardial strain mechanics relative to placebo (P < 0.01). The MSC-treated myocardium demonstrated enhanced neovessel formation (P < 0.0001), superior recruitment of endogenous c-kit+ cardiac stem cells to the RV (P < 0.0001) and increased proliferation of cardiomyocytes (P = 0.0009) and endothelial cells (P < 0.0001). Hypertrophic changes in the RV were more pronounced in the placebo group, as evidenced by greater wall thickness by echocardiography (P = 0.008), increased cardiomyocyte cross-sectional area (P = 0.001), and increased expression of hypertrophy-related genes, including brain natriuretic peptide, β-myosin heavy chain and myosin light chain. Additionally, MSC-treated myocardium demonstrated increased expression of the antihypertrophy secreted factor, growth differentiation factor 15 (GDF15), and its downstream effector, SMAD 2/3, in cultured neonatal rat cardiomyocytes and in the porcine RV myocardium. This is the first report of the use of MSCs as a therapeutic strategy to preserve RV function and attenuate remodeling in the setting of pressure overload. Mechanistically, transplanted MSCs possibly stimulated GDF15 and its downstream SMAD proteins to antagonize the hypertrophy response of pressure overload. These encouraging results have implications in congenital cardiac pressure overload lesions.

Topics: Animals; Disease Models, Animal; Humans; Hypertrophy, Right Ventricular; Mesenchymal Stem Cell Transplantation; Myosin Heavy Chains; Myosin Light Chains; Natriuretic Peptide, Brain; Swine; Ventricular Dysfunction, Right; Ventricular Pressure; 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

On trigeminal ganglion neurons, pain-sensing P2X3 receptors are constitutively inhibited by brain natriuretic peptide via its natriuretic peptide receptor-A. This inhibition is associated with increased P2X3 serine phosphorylation and receptor redistribution to non-lipid raft membrane compartments. The natriuretic peptide receptor-A antagonist anantin reverses these effects. We studied whether P2X3 inhibition is dysfunctional in a genetic familial hemiplegic migraine type-1 model produced by introduction of the human pathogenic R192Q missense mutation into the mouse CACNA1A gene (knock-in phenotype). This model faithfully replicates several properties of familial hemiplegic migraine type-1, with gain-of-function of CaV2.1 Ca(2+) channels, raised levels of the algogenic peptide calcitonin gene-related peptide, and enhanced activity of P2X3 receptors in trigeminal ganglia.. In knock-in neurons, anantin did not affect P2X3 receptor activity, membrane distribution, or serine phosphorylation level, implying ineffective inhibition by the constitutive brain natriuretic peptide/natriuretic peptide receptor-A pathway. However, expression and functional properties of this pathway remained intact together with its ability to downregulate TRPV1 channels. Reversing the familial hemiplegic migraine type-1 phenotype with the CaV2.1-specific antagonist, ω-agatoxin IVA restored P2X3 activity to wild-type level and enabled the potentiating effects of anantin again. After blocking calcitonin gene-related peptide receptors, P2X3 receptors exhibited wild-type properties and were again potentiated by anantin.. P2X3 receptors on mouse trigeminal ganglion neurons are subjected to contrasting modulation by inhibitory brain natriuretic peptide and facilitatory calcitonin gene-related peptide that both operate via complex intracellular signaling. In the familial hemiplegic migraine type-1 migraine model, the action of calcitonin gene-related peptide appears to prevail over brain natriuretic peptide, thus suggesting that peripheral inhibition of P2X3 receptors becomes insufficient and contributes to trigeminal pain sensitization.

Topics: Animals; Calcitonin Gene-Related Peptide Receptor Antagonists; Disease Models, Animal; Gene Knock-In Techniques; Mice; Migraine with Aura; Models, Biological; Natriuretic Peptide, Brain; omega-Agatoxin IVA; Peptides, Cyclic; Phenotype; Purinergic P2X Receptor Antagonists; Receptors, Atrial Natriuretic Factor; Receptors, Calcitonin Gene-Related Peptide; Receptors, Purinergic P2X3; Sensory Receptor Cells; Trigeminal Ganglion; TRPV Cation Channels

To investigate the effects of renal denervation (RDN) on comprehensive cardiac and renal fibrosis in cardiomyopathy. Five weeks after successful transverse aortic constriction (TAC)-induced cardiomyopathy model building, Sprague-Dawley rats were randomly assigned to three groups: (1) RDN, (2) sham, and (3) losartan. Sham TAC rats served as control group. Compared with control, TAC groups showed a significant decrease in left ventricle ejection fraction and increase in ventricular septum thickness and left atrium diameter on echocardiography after 5 weeks. At 10 weeks post-TAC, venous blood samples were collected for fibrosis biochemical assay. Heart and kidney samples were also harvested for fibrosis pathophysiological detection. Cardiac and renal fibrosis quantity results showed that, compared with sham group, collagen volume fraction was significantly decreased in RDN group more than in losartan group. Biochemical parameters such as tumor necrosis factor α, aldosterone, and B-type natriuretic peptide levels as well as biomarkers for fibrosis such as procollagen type I N-terminal propeptide and procollagen type III N-terminal propeptide concentrations were significantly decreased in RDN group in comparison with sham. In addition, compared with sham group, left ventricle tissue protein expression of transforming growth factor-β1 and angiotensin II type I receptor was downregulated, and angiotensin-converting enzyme 2 was upregulated in RDN but not in losartan group. RDN significantly attenuates cardiac and renal fibrosis in cardiomyopathy. Differing from losartan, which only has angiotensin II type I receptor inhibition effects, RDN comprehensively suppresses cardiac and renal fibrogenesis through multiple pathways.

Topics: Aldosterone; Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Animals; Biomarkers; Cardiomyopathies; Disease Models, Animal; Fibrosis; Heart Atria; Heart Ventricles; Humans; Kidney; Losartan; Myocardium; Natriuretic Peptide, Brain; Peptide Fragments; Procollagen; Rats; Rats, Sprague-Dawley; Renin-Angiotensin System; Sympathectomy

Purinergic P2X3 receptors (P2X3Rs) play an important role in pain pathologies, including migraine. In trigeminal neurons, P2X3Rs are constitutively downregulated by endogenous brain natriuretic peptide (BNP). In a mouse knock-in (KI) model of familial hemiplegic migraine type-1 with upregulated calcium CaV2.1 channel function, trigeminal neurons exhibit hyperexcitability with gain-of-function of P2X3Rs and their deficient BNP-mediated inhibition. We studied whether the absent BNP-induced control over P2X3Rs activity in KI cultures may be functionally expressed in altered firing activity of KI trigeminal neurons. Patch-clamp experiments investigated the excitability of wild-type and KI trigeminal neurons induced by either current or agonists for P2X3Rs or transient receptor potential vanilloid-1 (TRPV1) receptors. Consistent with the constitutive inhibition of P2X3Rs by BNP, sustained pharmacological block of BNP receptors selectively enhanced P2X3R-mediated excitability of wild-type neurons without affecting firing evoked by the other protocols. This effect included increased number of action potentials, lower spike threshold and shift of the firing pattern distribution toward higher spiking activity. Thus, inactivation of BNP signaling transformed the wild-type excitability phenotype into the one typical for KI. BNP receptor block did not influence excitability of KI neurons in accordance with the lack of BNP-induced P2X3R modulation. Our study suggests that, in wild-type trigeminal neurons, negative control over P2X3Rs by the BNP pathway is translated into tonic suppression of P2X3Rs-mediated excitability. Lack of this inhibition in KI cultures results in a hyperexcitability phenotype and might contribute to facilitated trigeminal pain transduction relevant for migraine.

Topics: Action Potentials; Adenosine Triphosphate; Animals; Capsaicin; Cells, Cultured; Cerebellar Ataxia; Disease Models, Animal; Electric Stimulation; Mice, Transgenic; Migraine Disorders; Natriuretic Peptide, Brain; Neural Inhibition; Neurons; Neurotransmitter Agents; Patch-Clamp Techniques; Peptides, Cyclic; Receptors, Atrial Natriuretic Factor; Receptors, Purinergic P2X3; Trigeminal Ganglion; TRPV Cation Channels

In Western countries heart disease is the leading cause of maternal death during pregnancy. The effect of pregnancy on the heart is difficult to study in patients with preexisting heart disease. Since experimental studies are scarce, we investigated the effect of pressure overload, produced by transverse aortic constriction (TAC) in mice, on the ability to conceive, pregnancy outcome, and maternal cardiac structure and function. Four weeks of TAC produced left ventricular (LV) hypertrophy and dysfunction with marked interstitial fibrosis, decreased capillary density, and induced pathological cardiac gene expression. Pregnancy increased relative LV and right ventricular weight without affecting the deterioration of LV function following TAC. Surprisingly, the TAC-induced increase in relative heart and lung weight was mitigated by pregnancy, which was accompanied by a trend towards normalization of capillary density and natriuretic peptide type A expression. Additionally, the combination of pregnancy and TAC increased the cardiac phosphorylation of c-Jun, and STAT1, but reduced phosphoinositide 3-kinase phosphorylation. Finally, TAC did not significantly affect conception rate, pregnancy duration, uterus size, litter size, and pup weight. In conclusion, we found that, rather than exacerbating the changes associated with cardiac pressure overload, pregnancy actually attenuated pathological LV remodeling and mitigated pulmonary congestion, and pathological gene expression produced by TAC, suggesting a positive effect of pregnancy on the pressure-overloaded heart.

Topics: Animals; Animals, Newborn; Aortic Valve Stenosis; Atrial Natriuretic Factor; Birth Weight; Capillaries; Disease Models, Animal; Echocardiography; Female; Fibrosis; Hypertrophy, Left Ventricular; Litter Size; Mice; Mice, Inbred C57BL; Myocardium; Myosin Heavy Chains; Natriuretic Peptide, Brain; Phosphatidylinositol 3-Kinases; Phosphorylation; Pregnancy; Pregnancy Complications, Cardiovascular; Pregnancy Rate; Proto-Oncogene Proteins c-jun; Real-Time Polymerase Chain Reaction; RNA, Messenger; Sarcoplasmic Reticulum Calcium-Transporting ATPases; STAT1 Transcription Factor; Time Factors; Transcriptome; Ventricular Dysfunction, Left

We aimed to understand the genetic control of cardiac remodeling using an isoproterenol-induced heart failure model in mice, which allowed control of confounding factors in an experimental setting. We characterized the changes in cardiac structure and function in response to chronic isoproterenol infusion using echocardiography in a panel of 104 inbred mouse strains. We showed that cardiac structure and function, whether under normal or stress conditions, has a strong genetic component, with heritability estimates of left ventricular mass between 61% and 81%. Association analyses of cardiac remodeling traits, corrected for population structure, body size and heart rate, revealed 17 genome-wide significant loci, including several loci containing previously implicated genes. Cardiac tissue gene expression profiling, expression quantitative trait loci, expression-phenotype correlation, and coding sequence variation analyses were performed to prioritize candidate genes and to generate hypotheses for downstream mechanistic studies. Using this approach, we have validated a novel gene, Myh14, as a negative regulator of ISO-induced left ventricular mass hypertrophy in an in vivo mouse model and demonstrated the up-regulation of immediate early gene Myc, fetal gene Nppb, and fibrosis gene Lgals3 in ISO-treated Myh14 deficient hearts compared to controls.

Topics: Animals; Disease Models, Animal; Echocardiography; Galectin 3; Gene Expression Regulation; Heart Failure; Heart Rate; Humans; Hypertrophy, Left Ventricular; Isoproterenol; Mice; Myocardium; Myosin Heavy Chains; Myosin Type II; Natriuretic Peptide, Brain; Quantitative Trait Loci; Ventricular Remodeling

A previous study found that brain natriuretic peptide (BNP) inhibited inflammatory pain via activating its receptor natriuretic peptide receptor A (NPRA) in nociceptive sensory neurons. A recent study found that functional NPRA is expressed in almost all the trigeminal ganglion (TG) neurons at membrane level suggesting a potentially important role for BNP in migraine pathophysiology.. An inflammatory pain model was produced by subcutaneous injection of BmK I, a sodium channel-specific modulator from venom of Chinese scorpion Buthus martensi Karsch. Quantitative PCR, Western Blot, and immunohistochemistry were used to detect mRNA and protein expression of BNP and NPRA in dorsal root ganglion (DRG) and dorsal horn of spinal cord. Whole-cell patch clamping experiments were conducted to record large-conductance Ca. The mRNA and protein expression of BNP and NPRA was up-regulated in DRG and dorsal horn of spinal cord after BmK I injection. The BNP and NPRA was preferentially expressed in small-sized DRG neurons among which BNP was expressed in both CGRP-positive and IB4-positive neurons while NPRA was preferentially expressed in CGRP-positive neurons. BNP increased the open probability of BK. These results suggested that BNP might play an important role as an endogenous pain reliever in BmK I-induced inflammatory pain condition. It is also suggested that BNP might play a similar role in other pathophysiological pain conditions including migraine.

Topics: Animals; Disease Models, Animal; Ganglia, Spinal; Male; Natriuretic Peptide, Brain; Neuralgia; Rats; Rats, Sprague-Dawley; Receptors, Atrial Natriuretic Factor; Scorpion Venoms; Sodium Channels; Spinal Cord

Heart failure(HF) is a dangerous disease that affects millions of patients. Radix Salvia is widely used in Chinese clinics to treat heart diseases. Salvianolic acid B(SalB) is the major active component of Radix Salvia. This study investigated the mechanisms of action and effects of SalB on HF in an experimental mouse model of HF.. We created a mouse model of HF by inducing pressure overload with transverse aortic constriction(TAC) surgery for 2 weeks and compared among 4 study groups: SHAM group (n = 10), TAC group (n = 9), TAC+MET group (metprolol, positive drug treatment, n = 9) and TAC+SalB group (SalB, 240 mg•kg-1•day-1, n = 9). Echocardiography was used to evaluate the dynamic changes in cardiac structure and function in vivo. Plasma brain natriuretic peptide (BNP) concentration was detected by Elisa method. In addition, H9C2 rat cardiomyocytes were cultured and Western blot were implemented to evaluate the phosphorylation of ERK1/2, AKT, and protein expression of GATA4.. SalB significantly inhibited the phosphorylation of Thr202/Tyr204 sites of ERK1/2, but not Ser473 site of AKT, subsequently inhibited protein expression of GATA4 and plasma BNP(P < 0.001), and then inhibited HF at 2 weeks after TAC surgery.. Our data provide a mechanism of inactivating the ERK1/2/GATA4 signaling pathway for SalB inhibition of the TAC-induced HF.

Topics: Animals; Aorta, Thoracic; Benzofurans; Blood Pressure; Cell Line; Disease Models, Animal; Drugs, Chinese Herbal; GATA4 Transcription Factor; Heart Failure; Heart Ventricles; Male; Mice; Mice, Inbred C57BL; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Signal Transduction

Cirrhosis is characterized by increased intrahepatic vascular resistance and enhanced vasocontractile responsiveness that impedes portal inflow and elevates portal pressure, in which endothelin-1 (ET-1) plays a role. Diabetes and glucose influence vasoresponsiveness but their impact on the intrahepatic vascular bed in cirrhosis is unknown. To investigate intrahepatic ET-1 vasoresponsiveness in cirrhotic rats with and without diabetes and to explore the underlying mechanisms.. Spraque-Dawley rats received common bile-duct ligation (BDL) to induce cirrhosis. Streptozotocin was injected to induce diabetes in the BDL rats (BDL/STZ). In situ liver perfusion was performed to obtain the ET-1 concentration-response curves. The basic hemodynamics and hepatic protein expressions of ET-1 receptors, pERK, ERK, pAkt, Akt, iNOS, eNOS, peNOS and calmodulin were evaluated. The circulating concentrations of N-terminal pro-brain natriuretic peptide (NT-ProBNP), blood urea nitrogen (BUN) and creatinine were also determined.. Body weight, mean arterial pressure, heart rate and survival rate were significantly decreased in the BDL/STZ rats. The perfusion pressure changes in response to ET-1 were higher in the BDL/STZ group for all perfusates. ETA receptor and pERK expressions were enhanced in the BDL/STZ group. The circulating concentrations of NT-ProBNP, BUN and creatinine, as well as SMA flow, were not significantly different between the BDL and BDL/STZ groups.. Cirrhotic rats with diabetes showed higher intrahepatic ET-1 vasoresponsiveness than normoglycemic cirrhotic rats. This effect is not affected by changes in perfused glucose concentration and may be related, at least in part, to intrahepatic ETA R receptor and pERK over-expression.

Topics: Animals; Blood Urea Nitrogen; Creatinine; Diabetes Mellitus, Experimental; Disease Models, Animal; eIF-2 Kinase; Endothelin-1; Hemodynamics; Hypertension, Portal; Liver Cirrhosis, Experimental; Male; Natriuretic Peptide, Brain; Peptide Fragments; Perfusion; Portal Pressure; Rats; Rats, Sprague-Dawley; Receptor, Endothelin A; Up-Regulation; Vasoconstriction

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

Pediatric pulmonary arterial hypertension (PAH) presents certain specific features. In this specific age group, experimental models to study the pathophysiology of PAH are lacking. To characterize hemodynamic, morphometric, and histological progression as well as the expression of neurohumoral factors and regulators of cardiac transcription in an infantile model of PAH induced by monocrotaline (MCT), eight-day-old Wistar rats were randomly injected with MCT (30 mg/kg, sc, n = 95) or equal volume of saline solution (n = 92). Animals were instrumented for biventricular hemodynamic recording 7, 14, and 21 days after MCT, whereas samples were collected at 1, 3, 7, 14, and 21 days after MCT. Different time point postinjections were defined for further analysis. Hearts and lungs were collected for morphometric characterization, assessment of right- and left-ventricle (RV and LV) cardiomyocyte diameter and collagen type-I and type-III ratio, RV collagen volume fraction, and pulmonary vessels wall thickness. mRNA quantification was undertaken for brain natriuretic peptide (BNP), endothelin-1 (ET-1), and for cardiac transcription regulators (HOP and Islet1). Animals treated with MCT at the 8th day of life presented RV hypertrophy since day 14 after MCT injection. There were no differences on the RV collagen volume fraction or collagen type-I and type-III ratio. Pulmonary vascular remodelling and PAH were present on day 21, which were accompanied by an increased expression of BNP, ET-1, HOP, and Islet1. The infantile model of MCT-induced PAH can be useful for the study of its pathophysiology and to test new therapeutic targets in pediatric age group.

Topics: Animals; Animals, Newborn; Collagen Type I; Collagen Type III; Disease Models, Animal; Endothelin-1; Female; Heart; Hemodynamics; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Lung; Male; Monocrotaline; Myocytes, Cardiac; Natriuretic Peptide, Brain; Pyrrolizidine Alkaloids; Rats; Rats, Wistar; RNA, Messenger; Time Factors; Transcription Factors

Natriuretic peptide receptor 3 (NPR3) is the clearance receptor for the cardiac natriuretic peptides (NPs). By modulating the level of NPs, NPR3 plays an important role in cardiovascular homeostasis. Although the physiological functions of NPR3 have been explored, little is known about its regulation in health or disease. MicroRNAs play an essential role in the post-transcriptional expression of many genes. Our aim was to investigate potential microRNA-based regulation of NPR3 in multiple models. Hypoxic challenge elevated levels of NPPB and ADM mRNA, as well as NT-proBNP and MR-proADM in human left ventricle derived cardiac cells (HCMa), and in the corresponding conditioned medium, as revealed by qRT-PCR and ELISA. NPR3 was decreased while NPR1 was increased by hypoxia at mRNA and protein levels in HCMa. Down-regulation of NPR3 mRNA was also observed in infarct and peri-infarct cardiac tissue from rats undergoing myocardial infarction. From microRNA microarray analyses and microRNA target predictive databases, miR-100 was selected as a candidate regulator of NPR3 expression. Further analyses confirmed up-regulation of miR-100 in hypoxic cells and associated conditioned media. Antagomir-based silencing of miR-100 enhanced NPR3 expression in HCMa. Furthermore, miR-100 levels were markedly up-regulated in rat hearts and in peripheral blood after myocardial infarction and in the blood from heart failure patients. Results from this study point to a role for miR-100 in the regulation of NPR3 expression, and suggest a possible therapeutic target for modulation of NP bioactivity in heart disease.

Topics: 3' Untranslated Regions; Adrenomedullin; Aged; Animals; Base Sequence; Binding Sites; Case-Control Studies; Culture Media, Conditioned; Disease Models, Animal; Down-Regulation; Female; Gene Expression Profiling; Gene Expression Regulation; Heart Failure; Humans; Hypoxia; Male; MicroRNAs; Middle Aged; Myocardial Infarction; Myocytes, Cardiac; Natriuretic Peptide, Brain; Peptide Fragments; Protein Precursors; Rats; Receptors, Atrial Natriuretic Factor; RNA Interference; RNA, Messenger; Time Factors

Thoracic spinal cord stimulation (SCS) has been shown to improve left ventricular ejection fraction (LVEF) in heart failure (HF). Nevertheless, the optimal duration (intermittent vs. continuous) of stimulation and the mechanisms of action remain unclear.. We performed chronic thoracic SCS at the level of T1-T3 (50 Hz, pulse width 0.2 ms) in 30 adult pigs with HF induced by myocardial infarction and rapid ventricular pacing for 4 weeks. All the animals were treated with daily oral metoprolol succinate (25 mg) plus ramipril (2.5 mg), and randomized to a control group (n = 10), intermittent SCS (4 h ×3, n = 10) or continuous SCS (24 h, n = 10) for 10 weeks. Serial measurements of LVEF and +dP/dt and serum levels of norepinephrine and B-type natriuretic peptide (BNP) were measured. After sacrifice, immunohistological studies of myocardial sympathetic and parasympathetic nerve sprouting and innervation were performed. Echocardiogram revealed a significant increase in LVEF and +dP/dt at 10 weeks in both the intermittent and continuous SCS group compared with controls (P < 0.05). In both SCS groups, there was diffuse sympathetic nerve sprouting over the infarct, peri-infarct, and normal regions compared with only the peri-infarct and infarct regions in the control group. In addition, sympathetic innervation at the peri-infarct and infarct regions was increased following SCS, but decreased in the control group. Myocardium norepinephrine spillover and serum BNP at 10 weeks was significantly decreased only in the continuous SCS group (P < 0.05).. In a porcine model of HF, SCS induces significant remodelling of cardiac sympathetic innervation over the peri-infarct and infarct regions and is associated with improved LV function and reduced myocardial norepinephrine spillover.

Topics: Animals; Biomarkers; Cardiac Pacing, Artificial; Disease Models, Animal; Electrocardiography; Female; Heart; Heart Failure; Male; Myocardial Infarction; Natriuretic Peptide, Brain; Nerve Regeneration; Norepinephrine; Random Allocation; Recovery of Function; Spinal Cord Stimulation; Stroke Volume; Swine; Sympathetic Nervous System; Thoracic Vertebrae; Time Factors; Ultrasonography; Ventricular Function, Left; Ventricular Pressure

Increasing numbers of animal and clinical investigations have demonstrated the effectiveness of long-term electrical vagal nerve stimulation (VNS) on chronic heart failure (CHF). The present study investigated the effects of short-term VNS on the hemodynamics of cardiac remodeling and cardiac excitation-contraction coupling (ECP) in an animal model of CHF following a large myocardial infarction. At 3 weeks subsequent to ligation of the left coronary artery, the surviving rats were randomized into vagal and sham-stimulated groups. The right vagal nerve of the CHF rats was stimulated for 72 h. The vagal nerve was stimulated with rectangular pulses of 40 ms duration at 1 Hz, 5 V. The treated rats, compared with the untreated rats, had significantly higher left ventricular ejection fraction (54.86 ± 9.73, vs. 45.60 ± 5.51%; P=0.025) and left ventricular fractional shortening (25.31 ± 6.30, vs. 15.42 ± 8.49%; P=0.013), and lower levels of brain natriuretic peptide (10.07 ± 2.63, vs. 19.95 ± 5.22 ng/ml; P=0.001). The improvement in cardiac pumping function was accompanied by a decrease in left ventricular end diastolic volume (1.11 ± 0.50, vs. 1.54 ± 0.57 cm(3); P=0.032) and left ventricular end systolic volume (0.50 ± 0.28, vs. 0.87 ± 0.36 cm(3); P=0.007). Furthermore, the expression levels of ryanodine receptor type 2 (RyR2) and sarcoplasmic reticulum calcium adenosine triphosphatase (SERCA2) were significantly higher in the treated rats compared with the untreated rats (P=0.011 and P=0.001 for RyR2 and SERCA2, respectively). Therefore, VNS was beneficial to the CHF rats through the prevention of cardiac remodeling and improvement of cardiac ECP.

Topics: Animals; Blood Pressure; Chronic Disease; Disease Models, Animal; Excitation Contraction Coupling; Heart Failure; Heart Rate; Heart Ventricles; Hemodynamics; Immunoenzyme Techniques; Male; Natriuretic Peptide, Brain; Rats; Rats, Wistar; Real-Time Polymerase Chain Reaction; Ryanodine Receptor Calcium Release Channel; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Vagus Nerve Stimulation; Ventricular Function, Left; Ventricular Remodeling

JAK/STAT signal pathway plays an important role in the inflammation process of acute lung injury (ALI). This study aimed to investigate the correlation between recombinant human brain natriuretic peptide (rhBNP) and the JAK/STAT signaling pathway and to explore the protective mechanism of rhBNP against trauma-induced ALI.. The arterial partial pressure in oxygen, lung wet-dry weight ratios, protein content in bronchoalveolar lavage fluid, the histopathologic of the lung, as well as the protein expressions of STAT1, JAK2, and STAT3 were detected.. Sprague-Dawley rats were randomly divided into five groups: a control group, a sham-operated group, an ALI group, an ALI + rhBNP group, and an ALI + AG490 group. At 4 hours, 12 hours, 1 day, 3 days, and 7 days after injury, injured lung specimens were harvested. rhBNP pretreatment significantly ameliorated hypoxemia and histopathologic changes and alleviated pulmonary edema in trauma-induced ALI rats. rhBNP pretreatment reduced the phosphorylated protein and total protein level of STAT1. Similarly to JAK-specific inhibitor AG490, rhBNP was shown to significantly inhibit the phosphorylation of JAK2 and STAT3 in rats with trauma-induced ALI.. Our experimental findings indicated that rhBNP can protect rats against trauma-induced ALI and that its underlying mechanism may be related to the inhibition of JAK/STAT signaling pathway activation.

Topics: Acute Lung Injury; Animals; Blotting, Western; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Immunohistochemistry; Janus Kinase 1; Male; Natriuretic Agents; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Signal Transduction; STAT Transcription Factors; Wounds and Injuries

Fractalkine (FKN) was recently shown to play an important role in atherosclerotic plaque rupture and cardiac remodeling and dysfunction. We evaluated the changes in serum FKN (sFKN) in patients with acute ST-elevation myocardial infarction (STEMI) and the influence of a percutaneous coronary intervention (PCI) on the levels of sFKN.. The study population included 40 patients with acute STEMI [acute myocardial infarction (AMI)+PCI: 20 underwent primary PCI; AMI: 20 without PCI] and 40 patients with symptomatic stable angina pectoris (SAP+PCI: 20 underwent PCI; SAP: 20 without PCI). sFKN were measured at different time points by ELIZA. The gene expression of heart FKN was assessed by real-time reverse transcription-PCR in a model of myocardial infarction mice.. We found that the baseline level of sFKN in patients with acute STEMI was significantly higher than that of patients with SAP. Primary PCI in STEMI resulted in a rapid decrease within 24 h and to a similar level after 48 h as in the SAP and SAP+PCI patients, whereas in the AMI group, the sFKN level showed a slight decrease from 6 to 24 h (from 1307.6±368.9 to 1092.7±258.1 pg/ml, P=0.036) and remained significantly higher at all later time points (P<0.001 for all). The sFKN level at 30 days was correlated positively with the NT-proBNP level (r=0.490, P=0.014). The time course of myocardial FKN gene expression in mice has a pattern similar to sFKN change in AMI patients.. Our study suggested that STEMI had a higher sFKN level and correlated positively with the NT-proBNP level at 1 month. PCI could lead to a rapid decrease in the sFKN level.

Topics: Aged; Angina, Stable; Animals; Biomarkers; Chemokine CX3CL1; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Mice, Inbred C57BL; Middle Aged; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain; Peptide Fragments; Percutaneous Coronary Intervention; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Time Factors; Treatment Outcome

Altered myocardial structure and function, secondary to chronically elevated blood pressure, are leading causes of heart failure and death. B-type natriuretic peptide (BNP), a guanylyl cyclase A agonist, is a cardiac hormone integral to cardiovascular regulation. Studies have demonstrated a causal relationship between reduced production or impaired BNP release and the development of human hypertension. However, the consequences of BNP insufficiency on blood pressure and hypertension-associated complications remain poorly understood. Therefore, the goal of this study was to create and characterize a novel model of BNP deficiency to investigate the effects of BNP absence on cardiac and renal structure, function, and survival. Genetic BNP deletion was generated in Dahl salt-sensitive rats. Compared with age-matched controls, BNP knockout rats demonstrated adult-onset hypertension. Increased left ventricular mass with hypertrophy and substantially augmented hypertrophy signaling pathway genes, developed in young adult knockout rats, which preceded hypertension. Prolonged hypertension led to increased cardiac stiffness, cardiac fibrosis, and thrombi formation. Significant elongation of the QT interval was detected at 9 months in knockout rats. Progressive nephropathy was also noted with proteinuria, fibrosis, and glomerular alterations in BNP knockout rats. End-organ damage contributed to a significant decline in overall survival. Systemic BNP overexpression reversed the phenotype of genetic BNP deletion. Our results demonstrate the critical role of BNP defect in the development of systemic hypertension and associated end-organ damage in adulthood.

Topics: Age of Onset; Animals; Compliance; Death, Sudden, Cardiac; Disease Models, Animal; Fibrosis; Gene Expression Regulation; Gene Knockout Techniques; Humans; Hypertension; Hypertrophy, Left Ventricular; Kidney Glomerulus; Long QT Syndrome; Myocardial Contraction; Myocardium; Natriuretic Peptide, Brain; Phenotype; Rats; Rats, Inbred Dahl; Recombinant Fusion Proteins; Renal Insufficiency, Chronic; Signal Transduction

Sympathetic activation and parasympathetic withdrawal are important characteristics of heart failure. Recent studies demonstrate that galanin reduces the discharge of acetylcholine and inhibits vagal bradycardia by acting on galanin receptor type 1 (GalR1). We speculated that blocking GalR1 is beneficial for heart failure.. Rats with heart failure were induced by myocardial infarction. The rats were injected intraperitoneally with galanin receptor antagonist M40 solution (30 nmol/kg) or saline for 4 weeks. Cardiac function was assessed by echocardiography and brain natriuretic peptide (BNP) in plasma. The ratio of heart weight to body weight (HW/BW), hematoxylin-eosin (HE), and Masson trichrome stain was used to evaluate cardiac remodeling. Tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6) in plasma, and sarco(endo)plasmic reticulum Ca(2+) -ATPase (SERCA2) in heart tissue were detected to confirm the mechanism of the cardioprotection effect.. Compared with rats injected with saline, M40 effectively improved cardiac function of contraction; decreased BNP, IL-6, and HW/BW (all P < 0.05); attenuated cardiac fibrosis; and upregulated SERCA2 (P < 0.05).. M40 improves cardiac function and attenuates remodeling, suggesting that galanin receptor antagonist may be a potential therapeutic agent for HF.

Topics: Animals; Cardiotonic Agents; Coloring Agents; Disease Models, Animal; Electrocardiography; Endomyocardial Fibrosis; Enzyme-Linked Immunosorbent Assay; Galanin; Heart Failure; Interleukin-6; Male; Myocardium; Natriuretic Peptide, Brain; Organ Size; Peptide Fragments; Rats; Rats, Sprague-Dawley; Receptors, Galanin; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Tumor Necrosis Factor-alpha; Ventricular Remodeling

We studied whether vasopeptidase inhibition corrects the structure and function of the small arteries in experimental chronic renal insufficiency (CRI).. After 5/6 nephrectomy (NX) surgery was performed on rats, there was a 14-week follow-up, allowing CRI to become established. Omapatrilat (40 mg/kg/day in chow) was then given for 8 weeks, and the small mesenteric arterial rings were investigated in vitro using wire and pressure myographs.. Plasma and ventricular B-type natriuretic peptide (BNP) concentrations were increased 2- to 2.7-fold, while systolic blood pressure (BP) increased by 32 mm Hg after NX. Omapatrilat treatment normalized the BNP and reduced the BP by 45 mm Hg in the NX rats. Endothelium-dependent vasorelaxation was impaired but the response to acetylcholine was normalized after omapatrilat treatment. Vasorelaxations induced by nitroprusside, isoprenaline and levcromakalim were enhanced after omapatrilat, and the responses were even more pronounced than in untreated sham-operated rats. Arterial wall thickness and wall-to-lumen ratio were increased after NX, whereas omapatrilat normalized these structural features and improved the strain-stress relationship in the small arteries; this suggests improved arterial elastic properties.. Omapatrilat treatment reduced BP, normalized volume overload, improved vasorelaxation and corrected the dimensions and passive elastic properties of the small arteries in the NX rats. Therefore, we consider vasopeptidase inhibition to be an effective treatment for CRI-induced changes in the small arteries.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Blood Pressure; Disease Models, Animal; Dose-Response Relationship, Drug; Heart Ventricles; Male; Mesenteric Arteries; Natriuretic Peptide, Brain; Nephrectomy; Pyridines; Rats, Sprague-Dawley; Renal Insufficiency, Chronic; Thiazepines; Vascular Remodeling; Vascular Stiffness; Vasodilation; Vasodilator Agents

The present study involved both human cohorts and animal experiments to explore the performance of soluble CD146 (sCD146), a marker of endothelial function, as a diagnostic marker of acutely decompensated heart failure (ADHF), to determine the influence of patients' characteristics on that performance and to explore the potential application of CD146 in the pathophysiology of ADHF.. NT-proBNP and sCD146 were measured in three hundred ninety-one patients admitted to the emergency department for acute dyspnea. ROC curve analysis demonstrated that AUCs for ADHF diagnosis in dyspneic patients were 0.86 (95% CI: 0.82-0.90) for sCD146 and 0.90 (95% CI: 0.86-0.92) for NT-proBNP. Subgroup analyses demonstrated that adding sCD146 to NT-proBNP improved the diagnostic performance for patients lying in the gray zone of NT-proBNP (p=0.02) and could be especially useful for ruling-out ADHF. An experimental model of ADHF in rats using thoracic aortic constriction suggests that CD146 is expressed in the intima of large arteries and associated with both left ventricular function and organ congestion.. sCD146, a marker of endothelial function, seems to be as powerful as NT-proBNP is used to detect the cardiac origin of an acute dyspnea. The combination of sCD146 and NT-proBNP may have better performance than NT-proBNP used alone in particular for patients underlying in the "gray" zone and could therefore be an improved option for ruling-out ADHF. Both experimental and human data suggest that CD146 is related to systolic left ventricular function and to organ congestion.

Topics: Acute Disease; Aged; Aged, 80 and over; Animals; Biomarkers; CD146 Antigen; Disease Models, Animal; Echocardiography, Doppler; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Female; Follow-Up Studies; Heart Failure; Humans; Male; Middle Aged; Natriuretic Peptide, Brain; Peptide Fragments; Prognosis; Prospective Studies; Rats; ROC Curve; Vasodilation; Ventricular Function, Left

We aimed to observe the effects and mechanism of rhBNP treatment on myocardial fibrosis (MF) after myocardial infarction (MI).. SPF rats were separated into 3 groups: normal, MI (ligation of left coronary artery), and MI + rhBNP (recombinant human brain natriuretic peptide). Rats in MI + rhBNP group were given 30 μg/kg for 2 days before modeling and for 4 weeks after modeling. mRNA levels and the expression levels of TGF-β1 (transforming growth factor) and CTGF (connective tissue growth factor) in 3 groups were analyzed using the RT-qPCR and western blotting analysis, respectively. Furthermore, myocardial volume fraction (CVF) was analyzed using the Sirius Red F3B (SR) while the percentage of type I and III collagen in 3 groups were analyzed using the immunohistochemical staining.. Compared with the normal group, the levels of TGF-β1, CTGF, CVF, type I and III collagen were higher in MI group. However, mRNA levels of TGF-β1 and CTGF were significantly decreased in MI + rhBNP compared to MI groups. Expression of TGF-β1 was lower while that of CTGF was higher in MI + rhBNP group than that in MI group. Besides, CVF, and type I and III collagen were lower in MI + rhBNP group compared with MI group.. rhBNP could significantly decrease the TGF-β1 and CTGF levels in post-MI so as to inhibit the type I and III collagen deposition in MF of post-MI. rhBNP will be benefit for the improvement of MF.

Topics: Animals; Blotting, Western; Collagen; Disease Models, Animal; Fibrosis; Heart; Immunohistochemistry; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain; Rats; Recombinant Proteins; Reverse Transcriptase Polymerase Chain Reaction

It has been reported that Qiliqiangxin (QL), a traditional Chinese medicine compound, could inhibit cardiac hypertrophy and remodeling, and improve cardiac function. However, whether and how it reverses cardiac remodeling in rats post myocardial infarction (MI) remains unknown. This study aims to explore related mechanisms linked with cardiac function improvement and attenuation of cardiac remodeling by QL in rats with experimental MI.. MI was induced by ligation of left anterior descending coronary artery (LAD) in male Sprague-Dawley rats. Rats with LVEF < 50% at four weeks after procedure were treated for another 6 weeks with placebo, QL and captopril. Echocardiography and plasma NT-proBNP were measured at the end of study, and histological studies were performed. Protein expressions of Neuregulin-1 (NRG-1), total-Akt, phospho-Akt (Ser473), hydroxy-HIF-1α (Pro564), VEGF, Bax, Bcl-2 and Caspase 3 were examined by Western blot. mRNA expression of NRG-1 and p53 was detected by real-time PCR.. Compared with the placebo group, QL improved cardiac function, reduced left ventricular dimension, inhibited interstitial inflammation and fibrosis, increased neovascularization, and attenuated cardiomyocyte apoptosis. Meanwhile QL significantly upregulated the expression of HIF-1α, VEGF, enhanced phosphorylation of Akt, decreased the ratio of Bax/Bcl-2 and Caspase 3 expression. Furthermore, we observed upregulation of NRG-1 and downregulation of p53 after QL treatment.. Our data suggest that the beneficial effects of QL on improving cardiac function and attenuating cardiac remodeling post MI are associated with angiogenesis enhancement and apoptosis inhibition, which may be mediated via activation of NRG-1/Akt signaling and suppression of p53 pathway.

Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Cardiotonic Agents; Disease Models, Animal; Drugs, Chinese Herbal; Fibrosis; Male; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain; Neovascularization, Physiologic; Neuregulin-1; Peptide Fragments; Proto-Oncogene Proteins c-akt; Rats, Sprague-Dawley; Signal Transduction; Stroke Volume; Tumor Suppressor Protein p53; Vascular Endothelial Growth Factor A; Ventricular Function, Left; Ventricular Remodeling

Cardiac contusion is usually caused by blunt chest trauma and, although it is potentially a life-threatening condition, the diagnosis of a myocardial contusion is difficult because of non-specific symptoms and the lack of an ideal test to detect myocardial damage. Cardiac enzymes, such as creatine kinase (CK), creatine kinase MB fraction (CK-MB), cardiac troponin I (cTn-I), and cardiac troponin T (cTn-T) were used in previous studies to demonstrate the blunt cardiac contusion (BCC). Each of these diagnostic tests alone is not effective for diagnosis of BCC. The aim of this study was to investigate the serum heart-type fatty acid binding protein (h-FABP), N-terminal pro-B-type natriuretic peptide (NT-proBNP), CK, CK-MB, and cTn-I levels as a marker of BCC in blunt chest trauma in rats. The eighteen Wistar albino rats were randomly allocated to two groups; group I (control) (n=8) and group II (blunt chest trauma) (n=10). Isolated BCC was induced by the method described by Raghavendran et al. (2005). All rats were observed in their cages and blood samples were collected after five hours of trauma for the analysis of serum h-FABP, NT-pro BNP, CK, CK-MB, and cTn-I levels. The mean serum NT-pro BNP was significantly different between group I and II (10.3 ± 2.10 ng/L versus 15.4 ± 3.68 ng/L, respectively; P=0.0001). NT-pro BNP level >13 ng/ml had a sensitivity of 87.5%, a specificity of 70%, a positive predictive value of 70%, and a negative predictive value of 87.5% for predicting blunt chest trauma (area under curve was 0.794 and P=0.037). There was no significant difference between two groups in serum h-FABP, CK, CK-MB and c Tn-I levels. A relation between NT-Pro BNP and BCC was shown in this study. Serum NT-proBNP levels significantly increased with BCC after 5 hours of the blunt chest trauma. The use of NT-proBNP as an adjunct to other diagnostic tests, such as troponins, electrocardiography (ECG), chest x-ray and echocardiogram may be beneficial for diagnosis of BCC.

Topics: Animals; Area Under Curve; Biomarkers; Contusions; Creatine Kinase, MB Form; Disease Models, Animal; Fatty Acid Binding Protein 3; Fatty Acid-Binding Proteins; Heart Injuries; Myocardium; Natriuretic Peptide, Brain; Peptide Fragments; Predictive Value of Tests; Rats, Wistar; ROC Curve; Time Factors; Troponin I; Up-Regulation

To assess the impact of transfection with recombinant adenovirus vector-mediated Klotho gene on myocardial remodeling in a rat model of heart failure (HF) by intraperitoneal injection of isoproterenol.. Rats were divided into 5 groups by table of exponential random numbers: normal control group, HF group, saline-control HF group, recombinant adenovirus vector transfection group (Ad.EGFP group, 2 × 10¹⁰ pfu, 0.5 ml/rat), pDC316-CMV-EGFP-rKlotho transfection group (Ad.Klotho group, n=5 each). Left ventricular ejection fraction (LVEF) was obtained by echocardiography, hemodynamic parameters obtained by multi-channel physiological recorder, myocardial tissue underwent pathohistological examination. Additionally, the green fluorescin expression was observed on frozen heart section. Myocardial fibrosis correlated gene expression including Klotho gene, collagen I and III was detected by real time-PCR. Moreover, plasma levels of B-type natriuretic peptide (BNP) were measured with ELISA.. Compared to saline control HF group, LVEF, LVSP and ±dp/dtmax were significantly increased, myocardial fibrosis and myocardial remodeling were significantly attenuated in the Ad. Klotho group and there was green fluorescin distribution in myocardial tissues of Ad. Klotho group. Klotho expression was down-regulated and collagen I and III expression was upregulated in HF rats compared to normal control group (all P<0.05) and these changes could be significantly reversed in Ad. Klotho group (all P<0.05). Plasma BNP level was also significantly lower in Ad. Klotho group than in HF group (P<0.05).. Klotho gene transfection could improve cardiac function and attenuate cardiac remodeling and reducing myocardial fibrosis.

Topics: Adenoviridae; Animals; Disease Models, Animal; Echocardiography; Gene Expression; Genetic Vectors; Glucuronidase; Heart Failure; Hemodynamics; Isoproterenol; Klotho Proteins; Myocardium; Natriuretic Peptide, Brain; Rats; Transfection; Ventricular Function, Left

The cardioprotective effects of necroptosis inhibitor necrostatin-7 were studied in the rat model of permanent coronary occlusion. It was found that intraperitoneal injection of necrostatin-7 at a dose of 14.5 mg/kg 60 minutes prior to permanent left coronary artery occlusion reduced the amount of scar tissue and scar length in the left ventricle on the 21st day after surgery. In addition, pretreatment with necrostatin-7 resulted in decreased plasma level of N-terminal pro-brain natriuretic peptide, which points to the improvement in left ventricular function.

Topics: Animals; Apoptosis; Autophagy; Cicatrix; Coronary Vessels; Disease Models, Animal; Heart Ventricles; Male; Myocardial Infarction; Natriuretic Peptide, Brain; Peptide Fragments; Rats, Wistar; Thiazoles; Ventricular Remodeling

The intensity of accumulation and release of brain natriuretic peptide (BNP) in right atrial cardiac muscle cells was investigated in rats after 5 and 60 min from the reperfusion start. Total ischemia was simulated by cardiovascular bundle compression according to V. G. Korpachev. Immunocytochemical identification of BNP in atrial myocyte granules was investigated in ultrathin cuts. We applied polyclonal antibodies to BNP. The calculation of granules (A- and B-types) with BNP was carried out in (38 x 38 μm) visual fields in transmission electronic microscope. The results were assessed using Mann-Whitney U-test (p < 0.05). After 5 min from the reperfusion start, the amount of the granules with BNP did not change compared to intact animals rate. On the 60th min of the post-reperfusion period was shown active accumulation and release of BNP; the amount of A-type granules increased by 134%, B-type granules increased by 210 % in comparison with intacy level. The results showed stimulating effect of ischemic and reperfusion factors on the processes of the brain natriuretic peptide synthesis and secretion in the early post-reperfusion period.

Topics: Animals; Biomarkers; Cytoplasmic Granules; Disease Models, Animal; Heart Atria; Male; Myocardial Ischemia; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats; Reperfusion; Time Factors

The aim of this study was to determine if the atrial natriuretic peptide (ANP) precursor proANP is biologically active compared with ANP and B-type natriuretic peptide (BNP).. ProANP is produced in the atria and processed to ANP and activates the guanylyl cyclase receptor-A (GC-A) and its second messenger, cyclic guanosine monophosphate (cGMP). ProANP is found in the human circulation, but its bioavailability is undefined.. The in vivo actions of proANP compared with ANP, BNP, and placebo were investigated in normal canines (667 pmol/kg, n = 5/group). cGMP activation in human embryonic kidney 293 cells expressing GC-A or guanylyl cyclase receptor-B was also determined. ProANP processing and degradation were observed in serum from normal subjects (n = 13) and patients with heart failure (n = 14) ex vivo.. ProANP had greater diuretic and natriuretic properties, with more sustained renal tubular actions, compared with ANP and BNP in vivo in normal canines, including marked renal vasodilation not observed with ANP or BNP. ProANP also resulted in greater and more prolonged cardiac unloading than ANP but much less hypotensive effects than BNP. ProANP stimulated cGMP generation by GC-A as much as ANP. ProANP was processed to ANP in serum from normal control subjects and patients with heart failure ex vivo.. ProANP represents a novel activator of GC-A with enhanced diuretic, natriuretic, and renal vasodilating properties, and it may represent a key circulating natriuretic peptide in cardiorenal and blood pressure homeostasis. These results support the concepts that proANP may be a potential innovative therapeutic beyond ANP or BNP for cardiorenal diseases, including heart failure.

Topics: Animals; Atrial Natriuretic Factor; Blotting, Western; Cells, Cultured; Disease Models, Animal; Dogs; Female; Heart Failure; Humans; Kidney; Male; Natriuretic Peptide, Brain; Receptors, Atrial Natriuretic Factor

To investigate the effects of total flavonoids of propolis (TFP) on apoptosis of myocardial cells of chronic heart failure and its possible mechanism in rats.. Six male SD rats were randomly selected as normal control group, the remaining rats were made as chronic heart failure (CHF) model by intraperitoneal injection of adriamycin. The rats in the successful model were randomly divided into five groups (n = 6): CHF group, total flavonoids of propolis low dose group (LD group), total flavonoids of propolis middle dose group (MD group), total flavonoids of propolis high dose group (HD group), digoxin group (DIG group). After six week treatment, cardiac function indexes of rats were recorded by signal acquisition system; brain natriuretic peptide (BNP), cardiac troponin I (cTnI), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) content in plasma were detected; Myocardial morphological changes and collagen fiber hyperplasia by HE and Masson staining were observed; Myocardial apoptosis was detected with TUNEL method and protein connexin 43(P-Cx43) expression was detected by Western blot method.. Compared with NC group, left ventricular systolic pressure(LVSP) and maximal rise/fall velocity of left ventriculad pressure (± dP/dt(max)) absolute value in CHF group were significantly lowered (P < 0.01) while left ventricular end diastolic pressure (LVEDP) was increased significantly (P < 0.01); Contents of plasma BNP, cTnI, TNF-α and IL-6 in the CHF group were significantly improved (P < 0.01). Compared with CHF group, LVSP, ± dP/dt(max) absolute value in MD and HD groups were increased (P < 0.05), and LVEDP was significantly lowered (P < 0.01); LVEDP in LD group was significantly lowered (P < 0.01), changes in LVSP and ± dp/dt(max) absolue value were not obvious (P > 0.05). BNP, cTnI, TNF-α and IL-6 contents in MD and HD groups were significantly reduced (P < 0.01), but those plasma indicator changes were not obvious in LD group (P > 0.05). Western blot showed that P-Cx43 expression in CHF group was significantly higher than that in NC group (P < 0.01) and that in all TFP treatment groups it was decreased compared with CHF group (P < 0.05, P < 0.01), among which pairwise comparisons also showed differences (P < 0.05), myocardial apoptosis index (%)(22.62 ± 3.39) in CHF group was higher than that in NC group( 1.12 ± 0.24) (P < 0.01); compared with CHF group, the apoptosis index of myocardial cells (%) in LD,MD and HD groups, (15.79 + 2.8), (9.28 + 2.1) and (4.73 + 1.14) respectively, were significantly lower than those in the CHF group( P < 0.01). The expression level of P-Cx43 positively correlated with the apoptotic index (r = 0. 861, P < 0.01).. Total flavonaids of propolis have inhibitory effect on apoptosis of myocardial cells of chronic heart failure induced by adriamycin in rats, and the mechanism may be closely related to the regulation of Cx43 expression, especially the regulatory phosphorylation status.

Topics: Animals; Apoptosis; Chronic Disease; Connexin 43; Disease Models, Animal; Doxorubicin; Flavonoids; Heart Failure; Interleukin-6; Male; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phosphorylation; Propolis; Rats; Rats, Sprague-Dawley; Troponin I; Tumor Necrosis Factor-alpha

Inhibitory G (Gi) proteins have been proposed to be cardioprotective. We investigated effects of Gαi2 knockout on cardiac function and survival in a murine heart failure model of cardiac β1-adrenoceptor overexpression.. β1-transgenic mice lacking Gαi2 (β1-tg/Gαi2 (-/-)) were compared with wild-type mice and littermates either overexpressing cardiac β1-adrenoceptors (β1-tg) or lacking Gαi2 (Gαi2 (-/-)). At 300 days, mortality of mice only lacking Gαi2 was already higher compared with wild-type or β1-tg, but similar to β1-tg/Gαi2 (-/-), mice. Beyond 300 days, mortality of β1-tg/Gαi2 (-/-) mice was enhanced compared with all other genotypes (mean survival time: 363 ± 21 days). At 300 days of age, echocardiography revealed similar cardiac function of wild-type, β1-tg, and Gαi2 (-/-) mice, but significant impairment for β1-tg/Gαi2 (-/-) mice (e.g. ejection fraction 14 ± 2 vs. 40 ± 4% in wild-type mice). Significantly increased ventricle-to-body weight ratio (0.71 ± 0.06 vs. 0.48 ± 0.02% in wild-type mice), left ventricular size (length 0.82 ± 0.04 vs. 0.66 ± 0.03 cm in wild types), and atrial natriuretic peptide and brain natriuretic peptide expression (mRNA: 2819 and 495% of wild-type mice, respectively) indicated hypertrophy. Gαi3 was significantly up-regulated in Gαi2 knockout mice (protein compared with wild type: 340 ± 90% in Gαi2 (-/-) and 394 ± 80% in β1-tg/Gαi2 (-/-), respectively).. Gαi2 deficiency combined with cardiac β1-adrenoceptor overexpression strongly impaired survival and cardiac function. At 300 days of age, β1-adrenoceptor overexpression alone had not induced cardiac hypertrophy or dysfunction while there was overt cardiomyopathy in mice additionally lacking Gαi2. We propose an enhanced effect of increased β1-adrenergic drive by the lack of protection via Gαi2. Gαi3 up-regulation was not sufficient to compensate for Gαi2 deficiency, suggesting an isoform-specific or a concentration-dependent mechanism.

Topics: Animals; Atrial Natriuretic Factor; Cardiomyopathy, Dilated; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Disease Models, Animal; Gene Expression Regulation; Genetic Predisposition to Disease; GTP-Binding Protein alpha Subunit, Gi2; GTP-Binding Protein alpha Subunits, Gi-Go; Heart Failure; Mice, 129 Strain; Mice, Inbred C57BL; Mice, Knockout; Myocytes, Cardiac; Natriuretic Peptide, Brain; Phenotype; Receptors, Adrenergic, beta-1; Stroke Volume; Time Factors; Ultrasonography; Ventricular Function, Left; Ventricular Remodeling

Brain natriuretic peptide (BNP) has a protective effect on acute injury of the heart, brain, and lung. However, its role in acute kidney injury (AKI) remains unclear. The aim of this study was to investigate the effect of lyophilized recombinant human BNP (lrh-BNP) on AKI and the underlying molecular mechanisms. An experimental model for AKI was established using an ischemia/reperfusion (I/R) procedure. Healthy adult BALB/c mice were randomized to the sham, I/R, and lrh-BNP-treated post-I/R (BNP + I/R) groups. Post-operatively, the BNP + I/R group was subcutaneously injected with lrh-BNP (0.03 μg·kg(-1)·min(-1)), whereas the other groups received saline at the same dose. Serum creatinine (Scr) and blood urea nitrogen levels were examined; tissue staining was performed to evaluate the degree of I/R injury (IRI). Ki67 positive staining of renal tubular epithelial cells was observed using immunofluorescence confocal laser scanning to assess the effect of BNP on cell proliferation after IRI. Inflammatory factor expression levels were detected to evaluate the effect of BNP on renal inflammation. Compared with the sham group, the I/R group showed increased Scr levels, severe tubular injury of the renal outer medulla, increased Kim-1 mRNA expression, an increased number of infiltrative macrophages in the renal interstitium, and increased TNF-α, IL- 1β, IL-6, MCP-1, and HIF-1α mRNA expression. BNP delivery significantly reduced all pathological changes in the I/R group. The protective role of BNP in murine renal IRI may be associated with its inhibition of renal interstitial inflammation and hypoxia and its promotion of renal tubule repair.

Topics: Acute Kidney Injury; Animals; Disease Models, Animal; Epithelium; Humans; Hypoxia; Inflammation; Kidney Function Tests; Kidney Tubules; Male; Mice; Natriuretic Peptide, Brain; Protective Agents; Recombinant Proteins; Reperfusion Injury

Adiponectin is a protein secreted primarily by adipose tissue. It has been suggested that adiponectin plays a protective role in the early phase following myocardial infarction. Our primary aim was to investigate the effects of post-myocardial infarction heart failure well-characterized by left ventricular hemodynamic parameters on the total and high molecular weight adiponectin concentrations in plasma, fat and cardiac tissue. Eight weeks after myocardial infarction or sham operation, total and high molecular weight adiponectin concentrations in plasma, fat, and cardiac tissues were assayed in rats. In addition, hemodynamic parameters and expression of the genes encoding atrial natriuretic peptide and brain natriuretic peptide in left ventricle were evaluated. Atrial natriuretic peptide and brain natriuretic peptide mRNA levels in left ventricle tissue were higher in rats with myocardial infarction-induced heart failure compared with the controls. Similarly, total adiponectin concentration was increased in left ventricle (but not in right ventricle) in rats with post-myocardial infarction heart failure. In contrast, adiponectin levels in plasma and cardiac adipose tissue in rats with post-myocardial infarction heart failure were lower than in sham-operated animals. Furthermore, there were no significant differences in levels of high molecular weight adiponectin in plasma, cardiac tissue or adipose tissue between these two groups. We conclude that in the rat model of post-myocardial infarction heart failure, adiponectin level is increased in left ventricle tissue. This is accompanied by decreased adiponectin levels in plasma and cardiac adipose tissue.

Topics: Adiponectin; Adipose Tissue; Animals; Atrial Natriuretic Factor; Disease Models, Animal; Heart Failure; Heart Ventricles; Hemodynamics; Male; Molecular Weight; Myocardial Infarction; Natriuretic Peptide, Brain; Rats; Rats, Wistar; RNA, Messenger

Acute lung injury (ALI) is one of the most serious complications in traumatic patients and is an important part of multiple organ dysfunction syndrome (MODS). Recombinant human brain natriuretic peptide (rhBNP) is a peptide with a wide range of biological activity. In this study, we investigated local changes in oxidative stress and the NF-κB-dependent matrix metalloproteinase-9 (MMP-9) pathway in rats with trauma/haemorrhagic shock (TH/S)-induced ALI and evaluated the effects of pretreatment with rhBNP. Forty-eight rats were randomly divided into four groups: sham operation group, model group, low-dosage rhBNP group and high-dosage rhBNP group (n = 12 for each group). Oxidative stress and MPO activity were measured by ELISA kits. MMP-9 activity was detected by zymography analysis. NF-κB activity was determined using Western blot assay. With rhBNP pretreatment, TH/S-induced protein leakage, increased MPO activity, lipid peroxidation and metalloproteinase (MMP)-9 activity were inhibited. Activation of antioxidative enzymes was reversed. The phosphorylation of NF-κB and the degradation of its inhibitor IκB were suppressed. The results suggested that the protection mechanism of rhBNP is possibly mediated through upregulation of anti-oxidative enzymes and inhibition of NF-κB activation. More studies are needed to further evaluate whether rhBNP is a suitable candidate as an effective inhaling drug to reduce the incidence of TH/S-induced ALI.

Topics: Acute Lung Injury; Animals; Anti-Inflammatory Agents; Antioxidants; Disease Models, Animal; Humans; I-kappa B Proteins; Inflammation Mediators; Lipid Peroxidation; Male; Matrix Metalloproteinase 9; Natriuretic Peptide, Brain; NF-kappa B; Oxidative Stress; Peroxidase; Phosphorylation; Proteolysis; Rats, Sprague-Dawley; Recombinant Proteins; Shock, Hemorrhagic; Signal Transduction

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

The cardiac support device supports the heart and mechanically reduces left ventricular (LV) diastolic wall stress. Although it has been shown to halt LV remodeling in dilated cardiomyopathy, its therapeutic efficacy is limited by its lack of biological effects. In contrast, the slow-release synthetic prostacyclin agonist ONO-1301 enhances reversal of LV remodeling through biological mechanisms such as angiogenesis and attenuation of fibrosis. We therefore hypothesized that ONO-1301 plus a cardiac support device might be beneficial for the treatment of ischemic cardiomyopathy.. Twenty-four dogs with induced anterior wall infarction were assigned randomly to 1 of 4 groups at 1 week postinfarction as follows: cardiac support device alone, cardiac support device plus ONO-1301 (hybrid therapy), ONO-1301 alone, or sham control.. At 8 weeks post-infarction, LV wall stress was reduced significantly in the hybrid therapy group compared with the other groups. Myocardial blood flow, measured by positron emission tomography, and vascular density were significantly higher in the hybrid therapy group compared with the cardiac support device alone and sham groups. The hybrid therapy group also showed the least interstitial fibrosis, the greatest recovery of LV systolic and diastolic functions, assessed by multidetector computed tomography and cardiac catheterization, and the lowest plasma N-terminal pro-B-type natriuretic peptide levels (P < .05).. The combination of a cardiac support device and the prostacyclin agonist ONO-1301 elicited a greater reversal of LV remodeling than either treatment alone, suggesting the potential of this hybrid therapy for the clinical treatment of ischemia-induced heart failure.

Topics: Animals; Anterior Wall Myocardial Infarction; Biomarkers; Cardiomyopathies; Cardiovascular Agents; Chemistry, Pharmaceutical; Combined Modality Therapy; Coronary Circulation; Delayed-Action Preparations; Disease Models, Animal; Dogs; Fibrosis; Heart Ventricles; Heart-Assist Devices; Natriuretic Peptide, Brain; Peptide Fragments; Prostaglandins I; Prosthesis Design; Pyridines; Recovery of Function; Time Factors; Ventricular Function, Left; Ventricular Remodeling

Ventricular-arterial coupling is a measure of the relationship between ventricular contractility and afterload. We sought to determine the relationship between ventricular-arterial coupling and right ventricular (RV) remodeling in a novel porcine model of progressive pulmonary hypertension (PH).. Chronic PH was induced in pigs by ligation of the left pulmonary artery (PA) followed by 5 weekly injections of cyanoacrylate to progressively obstruct the right lower lobe arteries (PH group, n = 10). At 6 weeks, 5 PH animals underwent reperfusion of the left lung through conduit anastomosis to decrease RV afterload, whereas 5 other animals received no treatment. Five sham-operated piglets were used as controls. RV function was assessed using echocardiography and conductance catheterization. RV gene expression of beta-myosin heavy chain (β-MHC) and B-type natriuretic peptide (BNP) were quantified by polymerase chain reaction.. At 6 weeks, compared with controls, the PH group had higher mean PA pressure (32 ± 6 vs 14 ± 2 mm Hg, p < 0.01). The increase in RV elastance was insufficient to compensate for the increase in pulmonary arterial elastance in the PH group and altered ventricular-arterial coupling occurred (0.65 ± 0.16 vs 1.28 ± 0.14, p < 0.01). The degree of ventricular-arterial uncoupling was related to RV enlargement and systolic dysfunction. Ventricular-arterial uncoupling and increased RV mass index were associated with up-regulation of β-MHC and BNP expression.. Ventricular-arterial coupling is closely associated with ventricular remodeling and systolic function as well as contractile and BNP gene expression. Dynamic changes in myosin expression may determine RV work efficiency in PH.

Topics: Animals; Biomarkers; Cyanoacrylates; Disease Models, Animal; Hypertension, Pulmonary; Myosin Heavy Chains; Natriuretic Peptide, Brain; Pulmonary Artery; Swine; Ventricular Dysfunction, Right; Ventricular Remodeling

Recent advances in genome analysis have enabled the identification of numerous distal enhancers that regulate gene expression in various conditions. However, the enhancers involved in pathological conditions are largely unknown because of the lack of in vivo quantitative assessment of enhancer activity in live animals. Here, we established a noninvasive and quantitative live imaging system for monitoring transcriptional activity and identified a novel stress-responsive enhancer of Nppa and Nppb, the most common markers of heart failure. The enhancer is a 650-bp fragment within 50 kb of the Nppa and Nppb loci. A chromosome conformation capture (3C) assay revealed that this distal enhancer directly interacts with the 5'-flanking regions of Nppa and Nppb. To monitor the enhancer activity in a live heart, we established an imaging system using the firefly luciferase reporter. Using this imaging system, we observed that the novel enhancer activated the reporter gene in pressure overload-induced failing hearts (failing hearts: 5.7±1.3-fold; sham-surgery hearts: 1.0±0.2-fold; P<0.001, repeated-measures ANOVA). This method will be particularly useful for identifying enhancers that function only during pathological conditions.

Topics: 5' Flanking Region; Adrenergic alpha-1 Receptor Agonists; Animals; Animals, Newborn; Atrial Natriuretic Factor; Cells, Cultured; Disease Models, Animal; Enhancer Elements, Genetic; Gene Expression Regulation; Heart Failure; Humans; Luciferases; Luminescent Measurements; Mice; Mice, Inbred C57BL; Mice, Transgenic; Natriuretic Peptide, Brain; Natriuretic Peptide, C-Type; Protein Precursors; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; Stress, Physiological

Acromegaly is associated with an increased incidence of cardiovascular disease. Transgenic mice expressing bovine GH (bGH) gene have previously been used to examine the effects of chronic GH stimulation on cardiovascular function. Results concerning systolic blood pressure (SBP) in bGH mice are conflicting. We hypothesized that these discrepancies may be the result of the various ages of the mice used in previous studies. In the current study, SBP was assessed monthly in male bGH mice from 3-12 months of age. Factors known to alter blood pressure were assessed during this time and included: levels of brain natriuretic peptide (BNP) and glucose homeostasis markers, and renal levels of angiotensin-converting enzyme 2 and endothelial nitric oxide synthase. Beginning at 6 months of age bGH had increased SBP compared with wild-type controls, which remained elevated through 12 months of age. Despite having increased blood pressure and cardiac BNP mRNA, bGH mice had decreased circulating levels of BNP. Additionally, bGH mice had an age-dependent decline in insulin levels. For example, they were hyperinsulinemic at 3 months, but by 11 months of age were hypoinsulinemic relative to wild-type controls. This decrease in insulin was accompanied by improved glucose tolerance at 11 months. Finally, both angiotensin-converting enzyme 2 and endothelial nitric oxide synthase expression were severely depressed in kidneys of 11-month-old bGH mice. These results indicate that elevated SBP in bGH mice is dependent on age, independent of insulin resistance, and related to alterations in both the natriuretic peptide and renin-angiotensin systems.

Topics: Acromegaly; Angiotensin-Converting Enzyme 2; Animals; Blood Pressure; Body Composition; Body Weight; Cattle; Disease Models, Animal; Fibrosis; Gene Expression Regulation; Glucose; Glucose Tolerance Test; Growth Hormone; Homeostasis; Hypertension; Insulin; Kidney Glomerulus; Male; Mice; Mice, Transgenic; Natriuretic Peptide, Brain; Nitric Oxide Synthase Type III; Peptidyl-Dipeptidase A; Renin-Angiotensin System; Systole; Time Factors

Sepsis is the leading cause of death in the intensive care units worldwide. Proinflammatory cytokines such as TNF (tumor necrosis factor)-α and IL (interleukin)-6 mediate the pathogenesis of septic shock characterized by hemodynamic instability and end-stage multi-organ functional failure. Brain natriuretic peptide (BNP) has been used as a diagnostic and prognostic biomarker in the cardiovascular disorders. Most recently, plasma level of BNP has also been used to predict outcomes of critical illnesses including sepsis. We have recently reported that human recombinant BNP (rhBNP) could protect lungs from acute proinflammatory injury in response to LPS-injection. In the current study, using LPS (lipopolysaccharide)-induced canine sepsis models, we further investigated the effect of rhBNP on intestinal injury and its potential mechanisms. We have found that rhBNP (5μg or 10μg/kg weight) could significantly reduce intestinal tissue damage in response to LPS-injection in the dog sepsis models through down-regulating proinflammatory cytokines TNF-α and IL-6 (5-10 fold decrease compared to LPS-injection only group) by a mechanism of suppressing IκB phosphorylation and NF-κB expression. These findings suggest that BNP protect intestinal tissues from endotoxin-induced hyper-inflammatory injury and thus, may be used as therapeutic agents for sepsis.

Topics: Animals; Anti-Inflammatory Agents; Disease Models, Animal; Dogs; Humans; I-kappa B Proteins; Interleukin-6; Jejunum; Lipopolysaccharides; Natriuretic Peptide, Brain; NF-kappa B; Recombinant Proteins; Sepsis; Tumor Necrosis Factor-alpha

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

Clinical studies failed to prove convincingly efficiency of intravenous infusion of neseritide during heart failure and evidence suggested a pro-adrenergic action of B-type natriuretic peptide (BNP). However, subcutaneous BNP therapy was recently proposed in heart failure, thus raising new perspectives over what was considered as a promising treatment. We tested the efficiency of a combination of oral β1-adrenergic receptor blocker metoprolol and subcutaneous BNP infusion in decompensated heart failure.. The effects of metoprolol or/and BNP were studied on cardiac remodelling, excitation-contraction coupling and arrhythmias in an experimental mouse model of ischaemic heart failure following postmyocardial infarction. We determined the cellular and molecular mechanisms involved in anti-remodelling and antiarrhythmic actions. As major findings, the combination was more effective than metoprolol alone in reversing cardiac remodelling and preventing ventricular arrhythmia. The association of the two molecules improved cardiac function, reduced hypertrophy and fibrosis, and corrected the heart rate, sympatho-vagal balance (low frequencies/high frequencies) and ECG parameters (P to R wave interval (PR), QRS duration, QTc intervals). It also improved altered Ca(2+) cycling by normalising Ca(2+)-handling protein levels (S100A1, SERCA2a, RyR2), and prevented pro-arrhythmogenic Ca(2+) waves derived from abnormal Ca(2+) sparks in ventricular cardiomyocytes. Altogether these effects accounted for decreased occurrence of ventricular arrhythmias.. Association of subcutaneous BNP and oral metoprolol appeared to be more effective than metoprolol alone. Breaking the deleterious loop linking BNP and sympathetic overdrive in heart failure could unmask the efficiency of BNP against deleterious damages in heart failure and bring a new potential approach against lethal arrhythmia during heart failure.

Topics: Administration, Oral; Adrenergic beta-Antagonists; Animals; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Therapy, Combination; Electrocardiography; Heart Failure; Injections, Subcutaneous; Male; Metoprolol; Mice; Mice, Inbred C57BL; Natriuretic Agents; Natriuretic Peptide, Brain; Tachycardia, Ventricular; Treatment Outcome; Ventricular Remodeling

The renin-angiotensin-aldosterone system and cardiac natriuretic peptides [atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP)] are opposing control mechanisms for arterial blood pressure. Accordingly, an inverse relationship between plasma renin concentration (PRC) and ANP exists in most circumstances. However, PRC and ANP levels are both elevated in renovascular hypertension. Because ANP can directly suppress renin release, we used ANP knockout (ANP(-/-)) mice to investigate whether high ANP levels attenuate the increase in PRC in response to renal hypoperfusion, thus buffering renovascular hypertension. ANP(-/-) mice were hypertensive and had reduced PRC compared with that in wild-type ANP(+/+) mice under control conditions. Unilateral renal artery stenosis (2-kidney, 1-clip) for 1 wk induced similar increases in blood pressure and PRC in both genotypes. Unexpectedly, plasma BNP concentrations in ANP(-/-) mice significantly increased in response to two-kidney, one-clip treatment, potentially compensating for the lack of ANP. In fact, in mice lacking guanylyl cyclase A (GC-A(-/-) mice), which is the common receptor for both ANP and BNP, renovascular hypertension was markedly augmented compared with that in wild-type GC-A(+/+) mice. However, the higher blood pressure in GC-A(-/-) mice was not caused by disinhibition of the renin system because PRC and renal renin synthesis were significantly lower in GC-A(-/-) mice than in GC-A(+/+) mice. Thus, natriuretic peptides buffer renal vascular hypertension via renin-independent effects, such as vasorelaxation. The latter possibility is supported by experiments in isolated perfused mouse kidneys, in which physiological concentrations of ANP and BNP elicited renal vasodilatation and attenuated renal vasoconstriction in response to angiotensin II.

Topics: Animals; Atrial Natriuretic Factor; Blood Pressure; Disease Models, Animal; Hypertension, Renovascular; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Natriuretic Peptide, Brain; Receptors, Atrial Natriuretic Factor; Renin; Renin-Angiotensin System; Surgical Instruments; Vasoconstriction; Vasodilation

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

Although renal denervation (RD) has been shown to be effective in treating post- myocardial Infarction (MI) heart failure (HF) in animal models and clinical trials, its utility as a standalone treatment without traditional drug treatment for post-MI HF still needs to be investigated.. Rats were randomly assigned into seven experimental groups: N group (control group with no MI and no RD, n = 10), MI group (MI, n = 20), RD group (renal denervation, n = 10), RD-3d+MI group (RD performed three days before MI, n = 15), β-blocker-3d+MI group (Metoprolol treated three days before MI, n = 15), ACEI-3d+MI group (Perindopril treated three days before MI, n = 15), and ARB-3d+MI group (Losartan treated three days before MI, n = 15). Cardiac function, autonomic nervous system parameters, and neuroendocrine activities were evaluated 8 weeks post MI.. Compared to β-blockers, ACEIs, and ARBs, RD alone provided significantly better cardiac remodeling and function, enhanced water and sodium excretion, and improved autonomic modulation.. In this post-MI HF animal model, surgical RD provides effective autonomic modulation, inhibition of the RAAS, improved cardiac remodeling, and preserved renal function, without affecting normal circulation and cardiopulmonary function in normal rats. Compared to β-blocker, ACEI, and ARB single-drug therapies, RD alone is more efficacious. These results suggest that RD may be an effective treatment option for HF, especially in patients who have contraindications to drug therapy.

Topics: Adrenergic beta-Antagonists; Aldosterone; Angiotensin II; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Animals; Denervation; Disease Models, Animal; Endothelins; Heart Failure; Heart Rate; Hemodynamics; Kidney; Male; Myocardial Infarction; Natriuretic Peptide, Brain; Norepinephrine; Rats; Rats, Wistar; Renin; Treatment Outcome; Ventricular Function, Left

Trypanosoma cruzi (Tc), the etiological agent of Chagas disease, triggers multiple responses in the myocardium, a central organ of infection and pathology in the host. Parasite-driven induction of diverse regulators of cardiovascular function, including the vasoconstrictor endothelin-1 (ET-1), the inducible form of nitric oxide synthase (iNOS) and the B-type natriuretic peptide (BNP), has been linked to the development of severe chagasic cardiomyopathy. Our current goal was to analyze the participation of the zinc finger transcription factor GATA4, critically implicated in pathological cardiac hypertrophic response, in the generation of key mediators involved in the pathogenesis of Tc-elicited heart dysfunction. In this study, we found that the combined effects of Tc and ET-1 on atrial myocytes promoted the protein expression, phosphorylation and DNA-binding activity of GATA4, leading to augmented protein levels of iNOS and increased nitric oxide release. Moreover, Tc- and ET-1-co-activation of cardiomyocytes resulted in enhanced GATA4-dependent secretion of BNP. Accordingly, mice with chronic chagasic cardiomyopathy showed increased expression of GATA4, iNOS and BNP at inflammatory lesions in cardiac muscle. Our findings support a role for the GATA4 signaling pathway in the myocardial production of pathogenic mediators associated with Chagas heart disease, and may help define novel therapeutic targets.

Topics: Animals; Cells, Cultured; Chagas Cardiomyopathy; Disease Models, Animal; Endothelin-1; GATA4 Transcription Factor; Mice, Inbred BALB C; Myocardium; Natriuretic Peptide, Brain; Nitric Oxide; Nitric Oxide Synthase Type II; Signal Transduction; Trypanosoma cruzi

The physiological mechanisms involved in isoproterenol (ISO)-induced chronic heart failure (CHF) are not fully understood. In this study, we investigated local changes in cardiac aldosterone and its synthase in rats with ISO-induced CHF, and evaluated the effects of treatment with recombinant human brain natriuretic peptide (rhBNP). Sprague-Dawley rats were divided into 4 different groups. Fifty rats received subcutaneous ISO injections to induce CHF and the control group (n=10) received equal volumes of saline. After establishing the rat model, 9 CHF rats received no further treatment, rats in the low-dose group (n=8) received 22.5 μg/kg rhBNP and those in the high-dose group (n=8) received 45 μg/kg rhBNP daily for 1 month. Cardiac function was assessed by echocardiographic and hemodynamic analysis. Collagen volume fraction (CVF) was determined. Plasma and myocardial aldosterone concentrations were determined using radioimmunoassay. Myocardial aldosterone synthase (CYP11B2) was detected by quantitative real-time PCR. Cardiac function was significantly lower in the CHF group than in the control group (P<0.01), whereas CVF, plasma and myocardial aldosterone, and CYP11B2 transcription were significantly higher than in the control group (P<0.05). Low and high doses of rhBNP significantly improved hemodynamics (P<0.01) and cardiac function (P<0.05) and reduced CVF, plasma and myocardial aldosterone, and CYP11B2 transcription (P<0.05). There were no significant differences between the rhBNP dose groups (P>0.05). Elevated cardiac aldosterone and upregulation of aldosterone synthase expression were detected in rats with ISO-induced CHF. Administration of rhBNP improved hemodynamics and ventricular remodeling and reduced myocardial fibrosis, possibly by downregulating CYP11B2 transcription and reducing myocardial aldosterone synthesis.

Topics: Aldosterone; Animals; Cardiotonic Agents; Chronic Disease; Collagen; Cytochrome P-450 CYP11B2; Disease Models, Animal; Echocardiography; Fibrosis; Heart Failure; Hemodynamics; Humans; Isoproterenol; Long-Term Care; Male; Myocardium; Natriuretic Agents; Natriuretic Peptide, Brain; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Recombinant Proteins; Transcription, Genetic; Ventricular Remodeling

This study sought to assess whether renal sympathetic denervation (RSD) could suppress ventricular substrate remodelling and attenuate heart failure (HF) progression.. Nineteen dogs were randomised into three groups - seven sham-operated controls, six with right ventricular pacing to induce HF, and six with RSD followed eight weeks later by pacing induction of HF. Haemodynamic variables were monitored at baseline and after HF. Levels of ventricular interstitial fibrosis, BNP, Ang II, aldosterone and TGF-β were measured. All the dogs in the HF and HF﹢RSD groups showed increased left and right ventricular diastolic dimensions, but the dogs in the HF﹢RSD group had a higher left ventricular ejection fraction (LVEF) than the HF dogs (0.42±0.05 vs. 0.35±0.04, p<0.01). Compared with the dogs with HF alone, the HF+RSD dogs had lower left ventricular end-diastolic pressure (LVEDP) (3.3±1.6 vs. 25±3.7 mmHg, p<0.01) and less fibrous tissue. The levels of BNP, Ang II, aldosterone and TGF-β expression in ventricular tissue were higher in the HF dogs than in the sham-operated and HF﹢RSD dogs.. RSD suppressed ventricular substrate remodelling induced by long-term rapid ventricular pacing.

Topics: Aldosterone; Angiotensin II; Animals; Arrhythmias, Cardiac; Cardiac Pacing, Artificial; Catheter Ablation; Disease Models, Animal; Disease Progression; Dogs; Female; Fibrosis; Heart Failure; Heart Ventricles; Kidney; Male; Natriuretic Peptide, Brain; Sympathectomy; Time Factors; Transforming Growth Factor beta; Ventricular Function, Left; Ventricular Pressure; Ventricular Remodeling

To explore the effect of the autoantibody against the β3-adrenoceptor on rats with experimental heart failure.. The peptide corresponding to the sequence of β3 adrenoceptor was synthesized to actively immunize the rats, ELISA was used to detect the serum level of autoantibody against the β3-adrenoceptor (β3AA). Total IgGs were extracted from the serum containing β3AA in immunized rats. Aortic banding surgery was used to establish the heart failure model in male Wistar rats and rats were divided into the sham group (n = 8), heart failure group(n = 8),β3AA-immunized heart failure group (HF+β3AA, n = 8) and corresponding negative IgG-immunized heart failure group (HF+ IgG, n = 8).In 6 weeks and 8 weeks after aortic banding surgery, the serum levels of NT-pro brain natriuretic peptide (NT-proBNP) were assayed with ELISA assay and cardiac function was assessed by echocardiography.. β3AA was used to immunize rat with heart failure, the serum level of β3AA was stable at 50 days post immunization. At 8 weeks after aortic banding surgery, heart failure group showed significantly increased LVEDD [(6.92 ± 0.22) mm vs.(5.62 ± 0.19) mm, P < 0.001], LVESD [(4.63 ± 0.23) mm vs.(3.50 ± 0.20) mm, P < 0.01] and IVS [(2.44 ± 0.06) mm vs.(2.28 ± 0.05) mm, P < 0.05], and decreased LVEF[(62.07 ± 3.99)% vs.(79.63 ± 3.02)%, P < 0.01] and LVFS [(31.46 ± 3.22)% vs.(43.65 ± 2.68) %, P < 0.05] compared with the sham group.HF+β3AA IgG group showed decreased LVEDD [(6.07 ± 0.30) mm vs.(6.92 ± 0.24) mm, P < 0.05] and LVESD [(3.92 ± 0.22) mm vs.(4.68 ± 0.23) mm, P < 0.05], and higher LVEF [(70.29 ± 1.78)% vs.(61.95 ± 3.03)%, P < 0.05] and LVFS [(38.08 ± 2.32)% vs.(30.50 ± 1.82)%, P < 0.05] compared to the HF+ IgG group.In addition, compared with the HF+ IgG group, HF+β3AA IgG group showed decreased serum levels of NT-proBNP [(196.43 ± 6.56) pg/ml vs.(242.13 ± 7.86) pg/ml, P < 0.01].. Our results demonstrate that β3AA can improve cardiac function and reduce the serum levels of NT-proBNP in rat with heart failure.

Topics: Animals; Autoantibodies; Cardiotonic Agents; Disease Models, Animal; Heart Failure; Male; Natriuretic Peptide, Brain; Peptide Fragments; Rats; Rats, Wistar; Receptors, Adrenergic, beta-3

Vitamin D deficiency has been associated with cardiovascular dysfunction. We evaluated the role of the vitamin D receptor (VDR) in vascular endothelial function, a marker of cardiovascular health, at baseline and in the presence of angiotensin II, using an endothelial-specific knockout of the murine VDR gene. In the absence of endothelial VDR, acetylcholine-induced aortic relaxation was significantly impaired (maximal relaxation, endothelial-specific VDR knockout=58% versus control=73%; P<0.05). This was accompanied by a reduction in endothelial NO synthase expression and phospho-vasodilator-stimulated phosphoprotein levels in aortae from the endothelial-specific VDR knockout versus control mice. Although blood pressure levels at baseline were comparable at 12 and 24 weeks of age, the endothelial VDR knockout mice demonstrated increased sensitivity to the hypertensive effects of angiotensin II compared with control mice (after 1-week infusion: knockout=155±15 mm Hg versus control=133±7 mm Hg; P<0.01; after 2-week infusion: knockout=164±9 mm Hg versus control=152±13 mm Hg; P<0.05). By the end of 2 weeks, angiotensin II infusion-induced, hypertrophy-sensitive myocardial gene expression was higher in endothelial-specific VDR knockout mice (fold change compared with saline-infused control mice, type-A natriuretic peptide: knockout mice=3.12 versus control=1.7; P<0.05; type-B natriuretic peptide: knockout mice=4.72 versus control=2.68; P<0.05). These results suggest that endothelial VDR plays an important role in endothelial cell function and blood pressure control and imply a potential role for VDR agonists in the management of cardiovascular disease associated with endothelial dysfunction.

Topics: Acetylcholine; Angiotensin II; Animals; Aorta; Blood Pressure; Blotting, Western; Disease Models, Animal; DNA; Endothelial Cells; Endothelium, Vascular; Gene Expression Regulation; Humans; Hypertension; Immunohistochemistry; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Natriuretic Peptide, Brain; Rats; Receptors, Calcitriol; Vasodilation

There is considerable interest in the pleiotropic effects of statins and their potential role in the treatment of pulmonary hypertension. Previous experimental findings indicate that a combination of lipophilic statins with phosphodiesterase type-5 inhibitor, sildenafil, can offer preventive effects on rat monocrotaline-induced pulmonary hypertension. The present study is aimed to assess whether therapeutic regimen provides any benefits. Seven days after pulmonary hypertension induction, hydrophilic rosuvastatin and sildenafil were given for 14 days to male Wistar outbred rats. Right ventricular pressure, right ventricle mass and three biomarkers were evaluated after 21 days: brain natriuretic peptide, high-density lipoprotein cholesterol and vascular endothelial growth factor. The present study demonstrates that administration of hydrophilic statin with sildenafil results in reduction of pulmonary vascular remodeling and right ventricular pressure. The results of biochemical measurements may suggest that statins play a positive role in right ventricle function or the process of angiogenesis in pulmonary hypertension development.

Topics: Animals; Antihypertensive Agents; Arterial Pressure; Biomarkers; Cholesterol, HDL; Disease Models, Animal; Drug Therapy, Combination; Fluorobenzenes; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Male; Monocrotaline; Natriuretic Peptide, Brain; Phosphodiesterase 5 Inhibitors; Piperazines; Pulmonary Artery; Purines; Pyrimidines; Rats, Wistar; Rosuvastatin Calcium; Sildenafil Citrate; Sulfonamides; Time Factors; Vascular Endothelial Growth Factor A; Vascular Remodeling; Vasodilator Agents; Ventricular Function, Right; Ventricular Pressure

The present study was designed to investigate whether oxymatrine could attenuate isoproterenol-induced heart failure via regulation of asymmetric dimethylarginine (ADMA) metabolism in rats. Heart failure model was established by once daily subcutaneous injection of isoproterenol (5 mg/kg/d) to rats for 7 days. Simultaneously, oral administration of oxymatrine (25, 50 and 100 mg/kg/d) was started from day 1 to day 7, or with vehicle as corresponding controls. After continuous preventive administration of oxymatrine for 7 days, significant isoproterenol-induced heart failure characterized by hypertrophy and dysfunction of left ventricle, and elevation of brain natruretic peptide (BNP, a heart failure biomarker) and cardiac troponin I (cTn-I, a cardiac injury biomarker) was observed. Preventive oxymatrine significantly ameliorated the cardiac hypertrophy, improved the left ventricular dysfunction and reduced the increased BNP and cTn-I in serum of isoproterenol-treated rats. And obvious changes with decrease of systolic blood pressure and increase of heart rate were present in isoproterenol group and normalized by oxymatrine. Besides, prevention with oxymatrine significantly up-regulated the dimethylarginine dimethylaminohydrolase 2 (DDAH2) expression, which was followed by decreased serum ADMA, but it had no effect on protein arginine methyltransferase1 (PRMT1) expression that is up-regulated in isoproterenol-induced heart failure rats. These results manifested that preventive oxymatrine could ameliorate the hypertrophy and dysfunction of left ventricle of rats with heart failure, which is attributed to modulation of DDAH/ADMA metabolism pathway by oxymatrine.

Topics: Alkaloids; Amidohydrolases; Animals; Arginine; Cardiotonic Agents; Disease Models, Animal; Female; Heart Failure; Hemodynamics; Isoproterenol; Male; Metabolic Networks and Pathways; Myocardium; Natriuretic Peptide, Brain; Organ Size; Protein-Arginine N-Methyltransferases; Quinolizines; Rats; Rats, Sprague-Dawley; Troponin I

This study was aimed to establish a stable animal model of left ventricular hypertrophy (LVH) to provide theoretical and experimental basis for understanding the development of LVH. The abdominal aorta of male Wistar rats (80-100 g) was constricted to a diameter of 0.55 mm between the branches of the celiac and anterior mesenteric arteries. Echocardiography using a linear phased array probe was performed as well as pathological examination and plasma B-type natriuretic peptide (BNP) measurement at 3, 4 and 6 weeks after abdominal aortic constriction (AAC). The results showed that the acute mortality rate (within 24 h) of this modified rat model was 8%. Animals who underwent AAC demonstrated significantly increased interventricular septal (IVS), LV posterior wall (LVPWd), LV mass index (LVMI), cross-sectional area (CSA) of myocytes, and perivascular fibrosis; the ejection fraction (EF), fractional shortening (FS), and cardiac output (CO) were consistently lower at each time point after AAC. Notably, differences in these parameters between AAC group and sham group were significant by 3 weeks and reached peaks at 4th week. Following AAC, the plasma BNP was gradually elevated compared with the sham group at 3rd and 6th week. It was concluded that this modified AAC model can develop LVH, both stably and safely, by week four post-surgery; echocardiography is able to assess changes in chamber dimensions and systolic properties accurately in rats with LVH.

Topics: Animals; Aorta, Abdominal; Constriction, Pathologic; Disease Models, Animal; Echocardiography; Enzyme-Linked Immunosorbent Assay; Heart; Hypertrophy, Left Ventricular; Male; Myocardium; Natriuretic Peptide, Brain; Rats, Wistar; Time Factors

Autonomic dysfunction, characterized by sympathetic activation and vagal withdrawal, contributes to the progression of heart failure (HF). We hypothesized that chronic vagus nerve stimulation (VNS) could prevent left ventricular (LV) remodeling and dysfunction in a canine HF model induced by chronic mitral regurgitation (MR).. After the MR inducing procedure, 12 survived canines were randomly divided into the control (n = 6) and the VNS (n = 6) groups. At month 2, a VNS stimulator system was implanted in all canines. From month 3 to month 6, VNS therapy was applied in the VNS group but not in the control group. At month 6, compared with the control group, the canines in VNS group had significantly higher cardiac output (2.3 ± 0.3 versus 2.9 ± 0.4 L/min, P < 0.05, LV forward stroke volume (20.1 ± 3.7 versus 24.8 ± 3.9 ml, P < 0.05), and end-systolic stiffness constant (2.2 ± 0.3 versus 2.7 ± 0.3, P < 0.05). NT-proBNP and C-reactive protein were decreased significantly in the VNS group. However, no statistical difference was found in LV ejection fraction, LV end-diastolic dimension, LV end-diastolic volume, myocyte cross-sectional area, or collagen volume fraction between two groups.. Chronic VNS therapy may ameliorate MR-induced LV contractile dysfunction and improve the expression of biomarkers, but has less effect in improving LV chamber remodeling.

Topics: Animals; C-Reactive Protein; Collagen; Disease Models, Animal; Dogs; Female; Hemodynamics; Male; Mitral Valve Insufficiency; Natriuretic Peptide, Brain; Peptide Fragments; Pericardium; Vagus Nerve Stimulation; Ventricular Function, Left; Ventricular Remodeling

Calsequestrin-2 (CSQ2) is a resident glycoprotein of junctional sarcoplasmic reticulum that functions in the regulation of SR Ca(2+) release. CSQ2 is biosynthesized in rough ER around cardiomyocyte nuclei and then traffics transversely across SR subcompartments. During biosynthesis, CSQ2 undergoes N-linked glycosylation and phosphorylation by protein kinase CK2. In mammalian heart, CSQ2 molecules subsequently undergo extensive mannose trimming by ER mannosidase(s), a posttranslational process that often regulates protein breakdown. We analyzed the intact purified CSQ2 from mongrel canine heart tissue by electrospray mass spectrometry. The average molecular mass of CSQ2 in normal mongrel dogs was 46,306 ± 41 Da, corresponding to glycan trimming of 3-5 mannoses, depending upon the phosphate content. We tested whether CSQ2 glycan structures would be altered in heart tissue from mongrel dogs induced into heart failure (HF) by two very different experimental treatments, rapid ventricular pacing or repeated coronary microembolizations. Similarly dramatic changes in mannose trimming were found in both types of induced HF, despite the different cardiomyopathies producing the failure. Unique to all samples analyzed from HF dog hearts, 20-40 % of all CSQ2 contained glycans that had minimal mannose trimming (Man9,8). Analyses of tissue samples showed decreases in CSQ2 protein levels per unit levels of mRNA for tachypaced heart tissue, also indicative of altered turnover. Quantitative immunofluorescence microscopy of frozen tissue sections suggested that no changes in CSQ2 levels occurred across the width of the cell. We conclude that altered processing of CSQ2 may be an adaptive response to the myocardium under stresses that are capable of inducing heart failure.

Topics: Animals; Atrial Natriuretic Factor; Calsequestrin; Carbohydrate Conformation; Carbohydrate Sequence; Concanavalin A; Disease Models, Animal; Dogs; Endoplasmic Reticulum, Rough; Gene Expression; Glycosylation; Heart Failure; Heart Ventricles; HEK293 Cells; Humans; Mannans; Molecular Weight; Natriuretic Peptide, Brain; Protein Binding; Protein Processing, Post-Translational; RNA, Messenger; Spectrometry, Mass, Electrospray Ionization

Diabetic cardiomyopathy (DCM) is defined as structural and functional changes in the myocardium due to metabolic and cellular abnormalities induced by diabetes mellitus (DM). The impact of prediabetic conditions on the cardiac tissue remains to be elucidated. The goal of this study was to elucidate whether cardiac dysfunction is already present in a state of prediabetes, in the presence of insulin resistance, and to unravel the underlying mechanisms, in a rat model without obesity and hypertension as confounding factors.. Two groups of 16-week-old Wistar rats were tested during a 9 week protocol: high sucrose (HSu) diet group (n = 7) - rats receiving 35% of sucrose in drinking water vs the vehicle control group (n = 7). The animal model was characterized in terms of body weight (BW) and the glycemic, insulinemic and lipidic profiles. The following parameters were assessed to evaluate possible early cardiac alterations and underlying mechanisms: blood pressure, heart rate, heart and left ventricle (LV) trophism indexes, as well as the serum and tissue protein and/or the mRNA expression of markers for fibrosis, hypertrophy, proliferation, apoptosis, angiogenesis, endothelial function, inflammation and oxidative stress.. The HSu-treated rats presented normal fasting plasma glucose (FPG) but impaired glucose tolerance (IGT), accompanied by hyperinsulinemia and insulin resistance (P < 0.01), confirming this rat model as prediabetic. Furthermore, although hypertriglyceridemia (P < 0.05) was observed, obesity and hypertension were absent. Regarding the impact of the HSu diet on the cardiac tissue, our results indicated that 9 weeks of treatment might be associated with initial cardiac changes, as suggested by the increased LV weight/BW ratio (P < 0.01) and a remarkable brain natriuretic peptide (BNP) mRNA overexpression (P < 0.01), together with a marked trend for an upregulation of other important mediators of fibrosis, hypertrophy, angiogenesis and endothelial lesions, as well as oxidative stress. The inflammatory and apoptotic markers measured were unchanged.. This animal model of prediabetes/insulin resistance could be an important tool to evaluate the early cardiac impact of dysmetabolism (hyperinsulinemia and impaired glucose tolerance with fasting normoglycemia), without confounding factors such as obesity and hypertension. Left ventricle hypertrophy is already present and brain natriuretic peptide seems to be the best early marker for this condition.

Topics: Animals; Biomarkers; Blood Glucose; Disease Models, Animal; Early Diagnosis; Gene Expression Regulation; Hypertrophy, Left Ventricular; Insulin Resistance; Male; Natriuretic Peptide, Brain; Prediabetic State; Rats; Rats, Wistar

Intra-abdominal hypertension (IAH) can have a profound impact on the cardiovascular system. We hypothesized that natriuretic peptides (Nt-pro-ANP and Nt-pro-BNP) are produced in response to the cardiovascular changes observed in an experimental model of IAH.. Eleven female pigs were enrolled in this study. Four experimental phases were created: a baseline phase for instrumentation (T1); two subsequent phases (T2 and T3), in which helium pneumoperitoneum was established at 20 and 35 mm Hg, respectively; and the final phase (T4), in which abdominal desufflation took place. Hemodynamic parameters and concentrations of Nt-pro-ANP and Nt-pro-BNP were measured.. Central venous pressure and pulmonary capillary wedge pressure increased significantly during the elevation of intra-abdominal pressure (IAP) and returned to baseline after abdominal desufflation. Right and left transmural pressures remained unaffected by the elevation of IAP. Cardiac output decreased in phases T2 and T3 and was restored to baseline levels after abdominal desufflation. Systemic and pulmonary vascular resistances increased significantly with IAH and decreased after abdominal desufflation. Nt-pro-ANP did not change significantly in comparison to baseline. Nt-pro-BNP increased significantly in comparison to baseline at T3 and T4. Peak Nt-pro-BNP levels at T3 (peak IAP) correlated positively with indices of afterload at this time point, that is, systemic vascular resistance and pulmonary vascular resistance (r(2) = 0.38, P = 0.042 and r(2) = 0.55, P = 0.009, respectively). A strong negative correlation between Nt-pro-BNP and cardiac output at T3 was also demonstrated (r(2) = 0.58, P = 0.006).. IAH resulted in cardiovascular compromise. The unchanged Nt-pro-ANP concentrations might reflect unaltered atrial stretch with IAH, despite the elevation of right atrial filling pressure. The significant increase of Nt-pro-BNP in response to high levels of IAP may reflect left ventricular strain and dysfunction due to the severe IAH and provide an alternative marker in the monitoring of IAH.

Topics: Animals; Atrial Natriuretic Factor; Biomarkers; Blood Pressure; Disease Models, Animal; Female; Hemodynamics; Intra-Abdominal Hypertension; Natriuretic Peptide, Brain; Pulmonary Wedge Pressure; Swine

The C57BL/6 mouse strain is one of the most commonly used in experimental research. It is known to differ from other strains in baseline cardiovascular phenotypes as well as in response to pressure overload induced by aortic constriction. Since the generation of the C57BL/6 mouse line over a century ago, multiple substrains have been generated from the original. To identify potential substrain specific differences in response to pressure overload, we evaluated the effects of transverse aortic constriction (TAC) on survival, cardiac function, and expression of hypertrophic markers in three commonly used C57BL/6 substrains: C57BL/6J (JL), C57BL/6NCrl (CL), and C57BL/6NTac (TF). Survival and cardiac function were significantly lower in the CL and TF substrains compared with JL mice after TAC. Furthermore, the heart weight and lung weight as well as the expression of the hypertrophic marker Bnp were significantly greater in the CL mice compared with the JL. Histological assessment revealed marked left ventricular dilatation of CL and TF hearts while JL hearts showed increased wall thickness without dilatation. Our data demonstrate that cardiac response to pressure overload is distinct among the three commonly used C57BL/6 substrains of mice, which raises a cautionary note in study design and data interpretation.

Topics: Adaptation, Physiological; Animals; Aorta; Biomarkers; Cardiac Myosins; Disease Models, Animal; Gene Expression Regulation; Genotype; Heart Failure; Hypertrophy, Left Ventricular; Ligation; Male; Mice; Mice, Inbred C57BL; Myocardial Contraction; Myocardium; Myosin Heavy Chains; Natriuretic Peptide, Brain; Phenotype; RNA, Messenger; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Species Specificity; Time Factors; Ultrasonography; Ventricular Dysfunction, Left; Ventricular Function, Left

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

Early identification for heart failure (HF) may be useful for disease modifying treatment in order to reduce heart disease progression or even to reverse it. In our previous studies, we have revealed a group of heat shock proteins (HSPs) which might be related to neonatal rat cardiomyocyte hypertrophy by proteomic approach. Here, we confirm that HSPs, including HSP27 and HSP70, altered in the early stage of cardiac remodeling in vivo animal model. Furthermore, plasma concentrations of those HSPs and their potential screening value were evaluated at different stages in 222 patient subjects. Plasma HSP27, HSP70 and HSP90 were measured using enzyme-linked immunosorbent assay. Results indicate that HSP70 was positively correlated to the severity (progression) of HF (r = 0.456, p<0.001). The area under the rate of change (ROC) curve was 0.601 (p = 0.017) in patients with stage B HF and 0.835 (p<0.001) in those with stage C HF. However, HSP27 and HSP90 did not display significant changes in any stage of HF in this study. Taken together, plasma concentrations of HSP70 elevated with the progression of HF and might act as a potential screening biomarker for early diagnosis of HF.

Topics: Aged; Aged, 80 and over; Animals; Biomarkers; Case-Control Studies; Disease Models, Animal; Female; Heart Failure; HSP27 Heat-Shock Proteins; HSP70 Heat-Shock Proteins; HSP90 Heat-Shock Proteins; Humans; Male; Mice; Middle Aged; Natriuretic Peptide, Brain; Peptide Fragments; Risk Factors; ROC Curve; Severity of Illness Index

The present study addresses the hypothesis that the activity of dipeptidyl peptidase IV (DPPIV), an enzyme that inactivates peptides that possess cardioprotective actions, correlates with adverse outcomes in heart failure (HF). The therapeutic potential of DPPIV inhibition in preventing cardiac dysfunction is also investigated.. Measurements of DPPIV activity in blood samples obtained from 190 patients with HF and 42 controls demonstrated that patients with HF exhibited an increase of ≈130% in circulating DPPIV activity compared with healthy subjects. Furthermore, an inverse correlation was observed between serum DPPIV activity and left ventricular (LV) ejection fraction in patients with HF. Similarly, radiofrequency LV ablation-induced HF rats displayed higher DPPIV activity in the plasma (≈50%) and heart tissue (≈3.5-fold) compared with sham-operated rats. Moreover, positive correlations were observed between the plasma DPPIV activity and LV end-diastolic pressure and lung congestion. Two days after surgery, 1 group of LV ablation-induced HF rats was treated with the DPPIV inhibitor sitagliptin (40 mg/kg BID) for 6 weeks, whereas the remaining rats were administered water. Hemodynamic measurements demonstrated that radiofrequency LV-ablated rats treated with sitagliptin exhibited a significant attenuation of HF-related cardiac dysfunction, including LV end-diastolic pressure, systolic performance, and chamber stiffness. Sitagliptin treatment also attenuated cardiac remodeling and cardiomyocyte apoptosis and minimized pulmonary congestion.. Collectively, the results presented herein associate circulating DPPIV activity with poorer cardiovascular outcomes in human and experimental HF. Moreover, the results demonstrate that long-term DPPIV inhibition mitigates the development and progression of HF in rats.

Topics: Adult; Aged; Animals; Apoptosis; Biomarkers; Case-Control Studies; Dipeptidyl Peptidase 4; Dipeptidyl-Peptidase IV Inhibitors; Disease Models, Animal; Female; Glucagon-Like Peptide 1; Heart Failure; Hemodynamics; Humans; Male; Middle Aged; Myocardium; Natriuretic Peptide, Brain; Pulmonary Edema; Pyrazines; Rats; Rats, Wistar; Sitagliptin Phosphate; Triazoles; Up-Regulation; Ventricular Function, Left; Ventricular Remodeling

To investigate the expression of brain natriuretic peptide (BNP) in rat myocardial tissue after acute cardiac dysfunction and to explore the role of BNP in diagnosis of cardiac dysfunction in forensic practice.. Rat models of acute cardiac dysfunction were established. The expression of BNP protein and BNP mRNA in myocardial tissue after cardiac dysfunction were detected by immunohistochemistry, Western blotting and real-time RT-PCR.. The extent of positive staining of BNP increased over the time course during cardiac dysfunction. The expression of BNP showed mild positive in cardiomyocytes from 1 h to 2 h. From 4 h to 6 h, the expression was moderate positive. From 10 h to 12 h, the BNP showed a strongest positive expression. The expression of BNP presented a significant raise with the increasing time of cardiac dysfunction by Western blotting and real-time RT-PCR. The expression of BNP mRNA increased significantly 1 h after cardiac dysfunction.. Investigating the expression of BNP protein and BNP mRNA in myocardial tissue may provide a new approach to evaluate the cardiac function for forensic pathologists.

Topics: Animals; Disease Models, Animal; Forensic Pathology; Gene Expression Regulation; Heart Ventricles; Hemodynamics; Male; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley; RNA, Messenger; Time Factors

Natriuretic peptides (NPs) play an important role in obesity and aim of this study was to evaluate, in cardiac tissue of obese Zucker rats (O, n = 29) their transcriptomic profile compared to controls (CO, n = 24) by Real-Time PCR study; CNP protein expression was evaluated by immunostaining and immunometric tests. Myocardial histology was performed, confirming no alteration of organ structure. While ANP and BNP are cardiac peptides, CNP is mainly an endothelial hormone; thus its expression, as well as that of NPR-B and NPR-C, was also evaluated in kidney and lung of an animal subgroup (n = 20). In heart, lower BNP mRNA levels in O vs CO (p = 0.02) as well as ANP and CNP (p = ns), were detected. NPR-B/NPR-A mRNA was similar in O and CO, while NPR-C was numerically lower (p = ns) in O than in CO. In kidney, CNP/NPR-B/NPR-C mRNA was similar in O and CO, while in lung CNP/NPR-C expression decreased and NPR-B increased (p = ns) in O vs CO. Subdividing into fasting and hyperglycemic rats, the pattern of mRNA expression for each gene analyzed remained unchanged. The trend observed in heart, kidney and lung for CNP protein concentrations and immunohistochemistry reflected the mRNA expression. TNF-α and IL-6 mRNA were measured in each tissue and no significant genotype effect was detected in any tissue. The main NP variations were observed at the cardiac level, suggesting a reduced release by cardiac cells. The understanding of mechanisms involved in the modulation of the NP system in obesity could be a useful starting point for future clinical study devoted to identifying new obesity treatment strategies.

Topics: Animals; Cytokines; Disease Models, Animal; Gene Expression Profiling; Gene Expression Regulation; Inflammation Mediators; Kidney; Lung; Male; Myocardium; Natriuretic Peptide, Brain; Natriuretic Peptides; Obesity; Rats; Rats, Zucker; Transcriptome

B-type natriuretic peptide (BNP) and adiponectin play important role in the cardiovascular homeostasis regulation. We investigated BNP and adiponectin serum levels followed by isoproterenol (ISO) administration to rats and explored the relationship between them. Cardiac troponin I (cTnI) blood level was used as biochemical evidence of myocardial damage development. Adult male Wistar rats (average body weight 273.33 ± 21.63 g) were distributed into groups: control group received saline (n=6) and ISO groups (n=12) treated with ISO (subcutaneous single dose 100 mg/kg of rat body weight). ISO group was divided into two groups according to the time of BNP, adiponectin and cTnI determination: ISO I (n=6; 2 hours after ISO administration); ISO II (n=6; 4 hours after ISO administration). Blood for determination of parameters was taken from rat abdominal aorta. BNP, adiponectin and cTnI were determined by ELISA method. Data were statistically analysed by using SPSS version 13 computer program. P value less 0.05 was considered statistically significant. Blood BNP and adiponectin were lower at 2 hours after ISO administration in comparison with control group (p=0.004 for BNP and p=0.174 for adiponectin). Four hours after ISO administration, we have noted significant elevation of both parameters compared to ISO I group (p=0.004 for BNP; p=0.02 for adiponectin). Test of correlation have showed significant relation between their blood levels during experimental period (rho=0.577; p=0.01). BNP and adiponectin are not simple indicators of myocardial damage development. They have possible associated and additive effects in cardiovascular homeostasis regulation.

Topics: Adiponectin; Animals; Biomarkers; Disease Models, Animal; Heart Injuries; Isoproterenol; Male; Myocardium; Natriuretic Peptide, Brain; Rats; Rats, Wistar; Troponin I

Abnormalities of the mevalonate pathway, an important cellular metabolic pathway, are common in many diseases including cardiovascular disease. The mevalonate pathway related enzyme expressions in pressure overload-induced cardiac hypertrophy and associated diastolic dysfunction remains largely unknown. This study aims to investigate whether the expression of mevalonate pathway related enzyme is altered during the progression of cardiac hypertrophy and associated diastolic dysfunction induced by pressure overload.. Male Sprague-Dawley (SD) rats were randomly divided into two groups: the suprarenal abdominal aortic coarctation (AAC) group and the sham group.. Histological and echocardiographic assessments showed that there was a significant cardiovascular remodeling in the AAC group compared with the sham group after 3 weeks post-operatively, and the left ventricular (LV) diastolic function was reduced at 8 and 14 weeks post-operatively in the AAC group, without any change in systolic function during the study. The tissue of the heart and the abdominal aorta proximal to the coarctation showed over-expression of several enzymes, including 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), farnesyl diphosphate synthase (FDPS), farnesyltransferase-α (FNTA), farnesyltransferase-β (FNTB), geranylgeranyltransferase type I (GGTase-I) and the activation of their downstream proteins was enhanced.. AAC induced compensatory LV hypertrophy to decompensatory diastolic dysfunction, accompanied by altered expression of several key enzymes in the mevalonate pathway.

Topics: Alkyl and Aryl Transferases; Animals; Blood Pressure; Disease Models, Animal; Farnesyltranstransferase; Geranyltranstransferase; Heart Failure; Hydroxymethylglutaryl CoA Reductases; Hypertrophy, Left Ventricular; Male; Mevalonic Acid; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Natriuretic Peptide, Brain; ras Proteins; Rats; Rats, Sprague-Dawley; rhoA GTP-Binding Protein; Ventricular Pressure

The levels of brain natriuretic peptide (BNP) and monocyte chemoattractant protein-1 (MCP-1) are known to be increased in the sera of subjects with heart failure. Existing models do not account for the biomass of thrombus that occurs in patients undergoing myocardial infarction. In this study, we compared the expressions of sheep-derived genes for BNP, MCP-1, and atrial natriuretic peptide in a new large-animal model of thrombus-induced heart failure. Thrombus of autologous platelets was injected directly into the left circumflex coronary arteries of sheep. Cardiac ischemic injury was evaluated by troponin I levels, and heart failure progression was monitored with the aid of echocardiogram-based evaluation. After outlined time intervals, the sheep were killed and their hearts excised for tissue sampling. Reverse transcription polymerase chain reaction, Western blot, and enzyme-linked immunosorbent assay (ELISA) tests were performed to establish gene and protein expressions. At 72 hours after embolization, myocardial BNP and MCP-1 expressions had increased significantly in the ischemic region, compared either with the nonischemic region or with tissue from healthy sheep. As heart failure progressed to 90 days after embolization, the expression of BNP in the ischemic region decreased, whereas its expression in the nonischemic region increased several fold. In contrast, MCP-1 gene expression showed no changes in either tissue after 90 days of embolization. Plasma levels of BNP, determined by Western blot and ELISA, also correlated with the gene-expression studies. Our results show regional changes in BNP and MCP-1, as well as differences in the expression of these 2 genes.

Topics: Animals; Biomarkers; Blotting, Western; Chemokine CCL2; Coronary Thrombosis; Disease Models, Animal; Disease Progression; Enzyme-Linked Immunosorbent Assay; Follow-Up Studies; Gene Expression Regulation; Heart Failure; Natriuretic Peptide, Brain; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sheep, Domestic; Time Factors

The effects of ventricular restraint level on left ventricular reverse remodeling are not known. We hypothesized that restraint level affects the degree of reverse remodeling and that restraint applied in an adjustable manner is superior to standard, nonadjustable restraint.. This study was performed in 2 parts using a model of chronic heart failure in the sheep. In part I, restraint was applied at control (0 mm Hg, n = 3), low (1.5 mm Hg, n = 3), and high (3.0 mm Hg, n = 3) levels with an adjustable and measurable ventricular restraint (AMVR) device. Restraint level was not altered throughout the 2-month treatment period. Serial restraint level measurements and transthoracic echocardiography were performed. In part II, restraint was applied with the AMVR device set at 3.0 mm Hg (n = 6) and adjusted periodically to maintain that level. This was compared with restraint applied in a standard, nonadjustable manner using a mesh wrap (n = 6). All subjects were followed up for 2 months with serial magnetic resonance imaging.. In part I, there was greater and earlier reverse remodeling in the high restraint group. In both groups, the rate of reverse remodeling peaked and then declined as the measured restraint level decreased with progression of reverse remodeling. In part II, adjustable restraint resulted in greater reverse remodeling than standard restraint. Left ventricular end diastolic volume decreased by 12.7% (P = .005) with adjustable restraint and by 5.7% (P = .032) with standard restraint. Left ventricular ejection fraction increased by 18.9% (P = .014) and 14.4% (P < .001) with adjustable and standard restraint, respectively.. Restraint level affects the rate and degree of reverse remodeling and is an important determinant of therapy efficacy. Adjustable restraint is more effective than nonadjustable restraint in promoting reverse remodeling.

Topics: Animals; Biomarkers; Disease Models, Animal; Echocardiography; Heart Failure; Heart Function Tests; Heart Ventricles; Ligation; Magnetic Resonance Imaging; Matrix Metalloproteinase 2; Natriuretic Peptide, Brain; Sheep, Domestic; Ventricular Remodeling

This study aimed to investigate the effects of combined recombinant human brain natriuretic peptide (rhBNP) therapy and bone mesenchymal stem cell (BMSC) transplantation on cell survival in myocardial tissues and on heart function in a rat model of heart failure (HF). Rat BMSCs were isolated, amplified and adherent cultured in vitro. A rat model of HF was established via the intraperitoneal injection of doxorubicin (Adriamycin). The rats were randomly divided into normal, HF, BMSC, rhBNP and BMSC plus rhBNP groups. The BMSCs were administered once via tail vein injection and rhBNP was infused via the jugular vein. Echocardiography and polygraphy were used to evaluate heart function. An enzyme‑linked immunosorbent assay was used to detect the changes in brain natriuretic peptide (BNP) concentration prior to and following intervention. Western blot analysis was used to detect the expression of the myocardium‑specific proteins GATA-binding protein 4 (GATA-4), connexin 43 (Cx43) and cardiac troponin I (cTnI). The results of cardiac echocardiography and the hemodynamic data show that various indicators of left ventricular systolic function in the BMSC plus rhBNP group were significantly improved compared with those in the other groups (P<0.05). No significant differences in the improvement of cardiac function were observed between the BMSC and rhBNP groups (P>0.05). Following treatment, a significant difference in BNP levels was observed between the BMSC plus rhBNP and the BMSC groups (P<0.05). The GATA-4, Cx43 and cTnI expression levels in the BMSC plus rhBNP group were higher than those in the BMSC group. Compared with rhBNP treatment, BMSC transplantation alone does not significantly improve heart function. However, combining rhBNP therapy and BMSC transplantation increases the expression levels of GATA-4 and other proteins to improve cardiac systolic and diastolic function.

Topics: Animals; Connexin 43; Disease Models, Animal; Doxorubicin; Echocardiography; Femur; GATA4 Transcription Factor; Heart Failure; Humans; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Natriuretic Peptide, Brain; Rats; Rats, Wistar; Recombinant Proteins; Tibia; Troponin I; Ventricular Function, Left

Injury to the heart can result in cardiomyocyte hypertrophy, fibrosis, and cell death. Myocarditis sometimes progresses to dilated cardiomyopathy. We previously reported that ONO-1301, a synthetic prostacyclin agonist with thromboxane-synthase inhibitory activity, promotes production of hepatocyte growth factor (HGF) from various cell types and ameliorates ischemia-induced left ventricle dysfunction in the mouse, rat and pig. Here, we investigated the therapeutic efficacy of ONO-1301 in a rat model of myosin-induced experimental autoimmune myocarditis, in which the heart transits from an acute inflammatory phase to a chronic dilated cardiomyopathy phase. Four weeks after myosin injection to Lewis rats, ONO-1301 (6 mg/kg/day) was orally administered for 4 weeks (ONO-1301 group). Hemodynamic parameters and plasma brain natriuretic peptide (BNP) level were significantly improved by ONO-1301. Histological analysis revealed that capillary density in the myocardium was significantly increased by ONO-1301. ONO-1301 increased circulating endothelial progenitor cells (EPC) as determined by FACS analysis. These beneficial effects of ONO-1301 were partially abrogated by a neutralizing anti-HGF antibody (8 mg/kg/dose). These findings indicate beneficial effects of ONO-1301 in a rat experimental autoimmune myocarditis model.

Topics: Administration, Oral; Animals; Autoimmune Diseases; Cardiomyopathy, Dilated; Disease Models, Animal; Endothelial Cells; Hemodynamics; Male; Myocarditis; Myosins; Natriuretic Peptide, Brain; Pyridines; Rats; Rats, Inbred Lew; Stem Cells

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

Inherited dilated cardiomyopathy (DCM) is a progressive disease that often results in death from congestive heart failure (CHF) or sudden cardiac death (SCD). Mouse models with human DCM mutation are useful to investigate the developmental mechanisms of CHF and SCD, but knowledge of the severity of CHF in live mice is necessary. We aimed to diagnose CHF in live DCM model mice by measuring voluntary exercise using a running wheel and to determine causes of death in these mice.. A knock-in mouse with a mutation in cardiac troponin T (ΔK210) (DCM mouse), which results in frequent death with a t(1/2) of 70 to 90 days, was used as a DCM model. Until 2 months of age, average wheel-running activity was similar between wild-type and DCM mice (approximately 7 km/day). At approximately 3 months, some DCM mice demonstrated low running activity (LO: <1 km/day) while others maintained high running activity (HI: >5 km/day). In the LO group, the lung weight/body weight ratio was much higher than that in the other groups, and the lungs were infiltrated with hemosiderin-loaded alveolar macrophages. Furthermore, echocardiography showed more severe ventricular dilation and a lower ejection fraction, whereas Electrocardiography (ECG) revealed QRS widening. There were two patterns in the time courses of running activity before death in DCM mice: deaths with maintained activity and deaths with decreased activity.. Our results indicate that DCM mice with low running activity developed severe CHF and that running wheels are useful for detection of CHF in mouse models. We found that approximately half of ΔK210 DCM mice die suddenly before onset of CHF, whereas others develop CHF, deteriorate within 10 to 20 days, and die.

Topics: Animals; Atrial Natriuretic Factor; Biomarkers; Cause of Death; Disease Models, Animal; Electrocardiography; Fibrosis; Heart Failure, Diastolic; Humans; Lung; Mice; Mice, Transgenic; Myocardium; Natriuretic Peptide, Brain; Organ Size; Physical Conditioning, Animal; Running

Recent studies have shown that microRNAs (miRNAs), besides being potent regulators of gene expression, can additionally serve as circulating biomarkers of disease. The aim of this study is to determine if plasma miRNAs can be used as indicators of disease progression or therapeutic efficacy in hypertension-induced heart disease.. In order to define circulating miRNAs that change during hypertension-induced heart failure and that respond to therapeutic treatment, we performed miRNA arrays on plasma RNA from hypertensive rats that show signs of heart failure. Array analysis indicated that approximately one-third of the miRNAs on the array are detectable in plasma. Quantitative real-time polymerase chain reaction (PCR) analysis for a selected panel of miRNAs indicated that circulating levels of miR-16, miR-20b, miR-93, miR-106b, miR-223, and miR-423-5p were significantly increased in response to hypertension-induced heart failure, while this effect was blunted in response to treatment with antimiR-208a as well as an ACE inhibitor. Moreover, treatment with antimiR-208a resulted in a dramatic increase in one miRNA, miR-19b. A time course study indicated that several of these miRNA changes track with disease progression.. Circulating levels of miRNAs are responsive to therapeutic interventions and change during the progression of hypertension-induced heart disease.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Biomarkers; Captopril; Disease Models, Animal; Disease Progression; Enzyme-Linked Immunosorbent Assay; Gene Expression Profiling; Heart Failure; Hypertension; Male; MicroRNAs; Natriuretic Peptide, Brain; Oligonucleotide Array Sequence Analysis; Rats; Rats, Inbred Dahl; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Sodium Chloride; Treatment Outcome

Serial changes in plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) and atrial natriuretic peptide (ANP) concentrations are unknown in dogs with myocardial injury. The time-course secretory responses between NT-proBNP and ANP or cardiac troponin-T (cTnT) related to myocardial infarction (MI) were investigated in this study. Six dogs were anaesthetised and the left anterior descending artery was ligated. A transient decrease in cardiac function was detected 1h after MI but returned to baseline levels within 7 days and remained so for 6 months. Echocardiographic examination revealed focal ventricular dyskinesis throughout the study. Six months following MI, the left atrium to aorta ratio increased significantly although the relative wall thickness decreased significantly from baseline. Significantly elevated plasma NT-proBNP and cTnT concentrations were detected 1 day after MI and these gradually decreased over 28 days to baseline levels without left ventricular pressure elevation. Plasma ANP was elevated significantly 6 months after MI. The NT-proBNP assay is a helpful diagnostic indicator for identifying asymptomatic acute and subacute myocardial injury whereas plasma ANP concentration mainly reflects atrial dilation.

Topics: Animals; Atrial Natriuretic Factor; Biomarkers; Disease Models, Animal; Dog Diseases; Dogs; Female; Myocardial Ischemia; Natriuretic Peptide, Brain; Peptide Fragments; Predictive Value of Tests; Severity of Illness Index

Recent studies indicate that brain natriuretic peptide (BNP(1-32)) may be truncated into BNP(3-32) by dipeptidyl peptidase IV (DPP4) and that BNP(3-32) has reduced biological activities compared with BNP(1-32). We investigated if DPP4 contributes to the cardiorenal alterations and to the attenuated response to BNP seen in heart failure.. Haemodynamic and renal assessment was performed in 12 pigs at baseline, 4 weeks after pacing-induced heart failure, and during BNP infusion. They were randomized to either placebo or treatment with a DPP4 inhibitor, sitagliptin. After 4 weeks of pacing, heart rate was reduced compared with baseline in the sitagliptin group (60 ± 2 vs. 95 ± 16 b.p.m., P < 0.01), and an increase in stroke volume was observed in the sitagliptin group compared with placebo (+24 ± 6% vs. -17 ± 7%, P < 0.01). Glomerular filtration rate declined at week 4 compared with baseline in the placebo group (1.3 ± 0.4 vs. 2.3 ± 0.3 mL/kg/min, P < 0.01) but remained preserved in the sitagliptin group [1.8 ± 0.2 vs. 2.0 ± 0.3 mL/kg/min, P = NS (non-significant)]. In the sitagliptin group, BNP infusion improved end-systolic elastance (68 ± 5 vs. 31 ± 4 mmHg/kg/mL, P < 0.05), ventricular-arterial coupling, and mechanical efficiency. Compared with controls (n = 6), myocardial gene expression of BNP, interleukin-6, Na(+)-Ca(2+) exchanger, and calmodulin was up-regulated in the placebo group, but not in the sitagliptin group.. In pacing-induced heart failure, DPP4 inhibition preserves the glomerular filtration rate, modulates stroke volume and heart rate, and potentiates the positive inotropic effect of exogenous BNP at no energy expense.

Topics: Animals; Calmodulin; Cardiac Pacing, Artificial; Dipeptidyl Peptidase 4; Dipeptidyl-Peptidase IV Inhibitors; Disease Models, Animal; Female; Glomerular Filtration Rate; Heart Failure; Heart Rate; Hemodynamics; Interleukin-6; Natriuretic Peptide, Brain; Pyrazines; Sitagliptin Phosphate; Sodium-Calcium Exchanger; Swine; Triazoles

AM5 (adrenomedullin 5), a newly described member of the CGRP (calcitonin gene-related peptide) family, is reported to play a role in normal cardiovascular physiology. The effects of AM5 in HF (heart failure), however, have not been investigated. In the present study, we intravenously infused two incremental doses of AM5 (10 and 100 ng/min per kg of body weight each for 90 min) into eight sheep with pacing-induced HF. Compared with time-matched vehicle control infusions, AM5 produced progressive and dose-dependent increases in left ventricular dP/dt(max) [LD (low dose), +56 mmHg/s and HD (high dose), +152 mmHg/s] and cardiac output (+0.83 l/min and +1.81 l/min), together with decrements in calculated total peripheral resistance (-9.4 mmHg/min per litre and -14.7 mmHg/min per litre), mean arterial pressure (-2.8 mmHg and -8.4 mmHg) and LAP (left atrial pressure; -2.6 mmHg and -5.6 mmHg) (all P<0.001). HD AM5 significantly raised PRA (plasma renin activity) (3.5-fold increment, P<0.001), whereas plasma aldosterone levels were unchanged over the intra-infusion period and actually fell in the post-infusion period (70% decrement, P<0.01), resulting in a marked decrease in the aldosterone/PRA ratio (P<0.01). Despite falls in LAP, plasma atrial natriuretic peptide and B-type natriuretic peptide concentrations were maintained relative to controls. AM5 infusion also induced significant increases in urine volume (HD 2-fold increment, P<0.05) and urine sodium (2.7-fold increment, P<0.01), potassium (1.7-fold increment, P<0.05) and creatinine (1.4-fold increment, P<0.05) excretion and creatinine clearance (60% increment, P<0.05). In conclusion, AM5 has significant haemodynamic, endocrine and renal actions in experimental HF likely to be protective and compensatory in this setting. These results suggest that AM5 may have potential as a therapeutic agent in human HF.

Topics: Adrenomedullin; Aldosterone; Animals; Atrial Natriuretic Factor; Cyclic AMP; Disease Models, Animal; Female; Heart Failure; Hemodynamics; Humans; Infusions, Intravenous; Kidney; Natriuretic Peptide, Brain; Renin; Renin-Angiotensin System; Second Messenger Systems; Sheep, Domestic

To investigate the expressions of brain natriuretic peptide (BNP) and natriuretic peptide receptor (NPR-A) in the cord dorsal horn ganglion (DRG) of rat models of chronic nonbacterial prostatitis (CNP) and the relation of BNP and NPR-A with CNP-induced chronic pain.. We established CNP models in 30 healthy clean SD rats using Freund's complete adjuvant, and included another 10 in a sham-operation group. The prostate tissues were subjected to HE staining, and the expressions of BNP and NPR-A in the L5-S2 DRGs were detected by real-time PCR.. Higher degree of inflammation was related to longer modeling time. At 3, 7 and 10 days, the expressions of BNP in the CNP models were 2.16 +/- 0.35, 1.61 +/- 0.21 and 1.32 +/- 0.36, and those of NPR-A were 2.75 +/- 0.06, 2.15 +/- 0.15 and 1.04 +/- 0.13, respectively, significantly higher at 3 and 7 days as compared with the sham-operation group (P<0.05), but with no statistically significant difference at 10 days.. BNP and NPR-A are expressed in the L5-S2 DRGs of SD rats and their expressions can be upregulated by CNP. BNP and NPR-A may be involved in the mechanisms of CNP-induced pain.

Topics: Animals; Disease Models, Animal; Ganglia, Spinal; Male; Natriuretic Peptide, Brain; Prostatitis; Rats; Rats, Sprague-Dawley; Receptors, Atrial Natriuretic Factor

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

The information needed to diagnose pulmonary arterial hypertension (PAH) in dogs based on N-terminal pro B-type natriuretic peptide (NT-proBNP) and atrial natriuretic peptide (ANP) levels is unclear. In this study, serial changes in plasma NT-proBNP and ANP concentrations were evaluated in association with the development of chronic embolic pulmonary hypertension (CEPH). Six Beagle dogs underwent percutaneous pulmonary artery catheterization. CEPH was induced by the repeated injection of 300 μm microspheres into the pulmonary artery via the catheter. Measured peak systolic pulmonary arterial pressure (PAPs) was elevated up to 80 mm Hg at 90 days by repeated injection of microspheres. Echocardiographic examination showed significant increase in the main pulmonary artery enlargement, right ventricular dilation, transtricuspid late diastolic flow, and ventricular late diastolic myocardial velocity. Plasma concentrations of NT-proBNP and ANP were significantly increased by microsphere-induced severe CEPH, but not by mild CEPH. Measured PAPs correlated weakly with plasma NT-proBNP and ANP concentrations (r=0.63 and 0.69, respectively) and with several echocardiographic variables. Our results indicated that plasma ANP and NT-proBNP responded to severe PAH, but that they were not sensitive for mild PAH.

Topics: Animals; Atrial Natriuretic Factor; Disease Models, Animal; Dog Diseases; Dogs; Familial Primary Pulmonary Hypertension; Female; Hypertension, Pulmonary; Male; Microspheres; Natriuretic Peptide, Brain; Peptide Fragments; Pulmonary Artery; Pulmonary Embolism; Ultrasonography

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

The progression of hypertensive heart disease (HHD) to heart failure (HF) is associated with myocardial remodeling. Corresponding changes in three-dimensional organization of cardiac extracellular matrix have not been quantified or related fully to the development of HF. Spontaneously hypertensive rats (SHRs) and Wistar-Kyoto controls were studied at 3, 12, 18, and 24 mo. Hemodynamic and morphological data, brain natriuretic peptide levels, and echocardiography demonstrate four distinct disease stages: systemic hypertension, diastolic dysfunction, early systolic failure, and decompensated HF. Passive left ventricular (LV) pressure-volume relationships were determined in vitro. Transmural specimens from the anterior LV free wall were imaged using extended-volume confocal microscopy, and three-dimensional myocardial architecture was quantified. In SHRs, LV compliance was reduced at 12 mo and increased progressively thereafter. However, it was less than in controls for filling pressures <10 mmHg and not significantly different at ≥10 mmHg. Myocyte cross section was enlarged, with increased variability from 12 mo, while collagen fraction increased progressively. Perimysial collagen fraction remained unchanged with age, although endomysial collagen increased from 12 mo. Perimysial collagen between adjacent muscle layers fused at 12 mo and continued to thicken subsequently, while muscle layers became more dispersed and disordered. We conclude that LV dilatation, which accompanies decompensated HF in this model of HHD, is not due to LV "softening." While perimysial (and endomysial) collagen networks are substantially remodeled, they are not dissolved, as has been proposed. We argue that progressive disruption of the laminar organization of LV myocardium may contribute to impaired systolic function in HHD.

Topics: Animals; Collagen; Disease Models, Animal; Disease Progression; Echocardiography; Heart Failure; Heart Ventricles; Hypertension; Natriuretic Peptide, Brain; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Time Factors; Ventricular Dysfunction, Left; Ventricular Remodeling

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a lethal ventricular arrhythmia evoked by physical or emotional stress. Recessively inherited CPVT is caused by either missense or null-allele mutations in the cardiac calsequestrin (CASQ2) gene. It was suggested that defects in CASQ2 cause protein deficiency and impair Ca(2+) uptake to the sarcoplasmic reticulum and Ca(2+)-dependent inhibition of ryanodine channels, leading to diastolic Ca(2+) leak, after-depolarizations, and arrhythmia. To examine the effect of exercise training on left ventricular remodeling and arrhythmia, CASQ2 knockout (KO) mice and wild-type controls underwent echocardiography and heart rhythm telemetry before and after 6 wk of training by treadmill exercise. qRT-PCR and Western blotting were used to measure gene and protein expression. Left ventricular fractional shortening was impaired in KO (33 ± 5 vs. 51 ± 7% in controls, P < 0.05) and improved after training (43 ± 12 and 51 ± 9% in KO and control mice, respectively, P = nonsignificant). The exercise tolerance was low in KO mice (16 ± 1 vs. 29 ± 2 min in controls, P < 0.01), but improved in trained animals (26 ± 2 vs. 30 ± 3 min, P = nonsignificant). The hearts of KO mice had a higher basal expression of the brain natriuretic peptide gene. After training, the expression of natriuretic peptide genes markedly decreased, with no difference between KO and controls. Exercise training was not associated with a change in ventricular tachycardia prevalence, but appeared to reduce arrhythmia load, as manifested by a decrease in ventricular beats during stress. We conclude that, in KO mice, which recapitulate the phenotype of human CPVT2, exercise training is well tolerated and could offer a strategy for heart conditioning against stress-induced arrhythmia.

Topics: Animals; Atrial Natriuretic Factor; Blotting, Western; Calsequestrin; Disease Models, Animal; Exercise Therapy; Exercise Tolerance; Gene Expression Regulation; Genetic Predisposition to Disease; Male; Mice; Mice, Knockout; Myocardial Contraction; Myocardium; Natriuretic Peptide, Brain; Phenotype; Real-Time Polymerase Chain Reaction; Recovery of Function; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tachycardia, Ventricular; Time Factors; Ventricular Function, Left; Ventricular Remodeling

This study sought to determine the effect of combined treatment of hypoxia plus indomethacin on pulmonary vascular remodeling in fetal rats.. Hypoxia and indomethacin were used to treat pregnant rats during 19-21 days of gestation. The adventitia, media, and intima of pulmonary arteries from fetal rats were assessed. Western blots were used for determining the abundance of smooth muscle specific alpha-actin protein (α-SMA), elastin, and endothelial nitric oxide synthase (eNOS) in lung tissues. Plasma brain-type natriuretic peptide (BNP) levels, reflecting the increased right ventricular load or pulmonary arterial pressure, were detected.. The ratio of left ventricular free wall plus septum to right ventricular weight significantly increased in hypoxia plus indomethacin-treated group. The medial thickness percentage of pulmonary arteries of < 100 μm and ≥100 μm in diameter from hypoxia plus indomethacin-treated group was higher than that from control or single treatment group. Vascular elastin area percentage and immunostaining density of eNOS from the combined-treated group were higher than other groups. The relative abundance of α-SMA, elastin, and eNOS and plasma BNP levels in hypoxia plus indomethacin-treated group also significantly increased compared with other groups.. Hypoxia and indomethacin had synergistic effect on fetal pulmonary vascular remodeling. This rat model induced by combined treatments can mimic human persistent pulmonary hypertension of the newborn.

Topics: Actins; Animals; Animals, Newborn; Blotting, Western; Cardiovascular Agents; Disease Models, Animal; Elastin; Female; Humans; Hypoxia; Indomethacin; Infant, Newborn; Lung; Myocardium; Natriuretic Peptide, Brain; Nitric Oxide Synthase Type III; Persistent Fetal Circulation Syndrome; Pulmonary Artery; Rats; Rats, Sprague-Dawley

There are few experimental models of heart failure (HF) in large animals, despite structural and functional similarities to human myocardium. We have developed a porcine model of chronic tachycardia-induced cardiomyopathy.. Homogenous siblings of White Large breed swine (n=6) underwent continuous right ventricular (RV) pacing at 170 bpm; 2 subjects served as controls. In the course of RV pacing, animals developed a clinical picture of HF and were presented for euthanasia at subsequent stages: mild, moderate and end-stage HF. Left ventricle (LV) sections were analyzed histologically and relative ANP, BNP, phospholamban and sarcoplasmic reticulum calcium ATPase 2a transcript levels in LV were quantified by real time RT-PCR.. In the course of RV pacing, animals demonstrated reduced exercise capacity (time of running until being dyspnoeic: 6.6 ± 0.5 vs. 2.4 ± 1.4 min), LV dilatation (LVEDD: 4.9 ± 0.4 vs. 6.7 ± 0.4 cm), impaired LV systolic function (LVEF: 69 ± 8 vs. 32 ± 7 %), (all baseline vs. before euthanasia, all p<0.001). LV tissues from animals with moderate and end-stage HF demonstrated local foci of interstitial fibrosis, congestion, cardiomyocyte hypertrophy and atrophy, which was not detected in controls and mild HF animals. The up-regulation of ANP and BNP and a reduction in a ratio of sarcoplasmic reticulum calcium ATPase 2a and phospholamban in failing myocardium were observed as compared to controls.. In pigs, chronic RV pacing at relatively low rate can be used as an experimental model of HF, as it results in a gradual deterioration of exercise tolerance accompanied by myocardial remodeling confirmed at subcellular level.

Topics: Animals; Atrial Natriuretic Factor; Cardiac Pacing, Artificial; Cardiomyopathies; Chronic Disease; Disease Models, Animal; Exercise Test; Female; Natriuretic Peptide, Brain; Random Allocation; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Swine; Tachycardia

Aortic regurgitation (AR) is a chronic disease for which there is currently no approved medical treatment. We previously reported in an animal model that β-blockade with metoprolol exerted beneficial effects on left ventricular remodeling and survival. Despite the recent publication of promising human data, β-blockade in chronic AR remains controversial. More data are needed to support this potentially new treatment strategy. We hypothesized that carvedilol might be another safe treatment option in chronic AR, considering its combined β-blocking and α-blocking effects and proven efficacy in patients with established heart failure.. The effects of a 6-month treatment with carvedilol 30 mg/kg/d orally were evaluated in adult Wistar rats with severe AR. Sham-operated and untreated AR animals were used as controls. Carvedilol treatment resulted in less left ventricular hypertrophy and dilatation. Ejection fraction was improved and filling pressures were reduced by carvedilol. β1-Receptor expression was also improved as well as myocardial capillary density. Those beneficial effects were noted despite the presence of drug-induced bradycardia.. Carvedilol exerted protective effects against volume-overload cardiomyopathy in this model of aortic valve regurgitation with preserved ejection fraction. These results suggest a protective class effect of β-blockers. Combined with the recent publication of promising human data, our findings support the need to carefully design a prospective study in humans to evaluate the effects of β-blockers in chronic aortic valve regurgitation.

Topics: Administration, Oral; Adrenergic beta-Antagonists; Animals; Aortic Valve Insufficiency; Atrial Natriuretic Factor; Bradycardia; Capillaries; Carbazoles; Carvedilol; Chronic Disease; Disease Models, Animal; Extracellular Matrix Proteins; Follistatin-Related Proteins; Gene Expression Regulation; Heart Rate; Hypertrophy, Left Ventricular; Male; Natriuretic Peptide, Brain; Propanolamines; Rats; Rats, Wistar; Receptors, Adrenergic; RNA, Messenger; Stroke Volume; Time Factors; Ultrasonography; Ventricular Function, Left; Ventricular Pressure

Previous studies have shown protective effects of brain natriuretic peptide (BNP) against the postmyocardial infarction (MI) remodelling process. The transcription factor NF-κB is known to play an important role after MI.. To investigate if NF-κB is involved in the protective effects of BNP against adverse post-MI remodelling.. Rats were randomly assigned to five groups: sham-operation; MI by coronary ligation; MI treated with chronic BNP infusion; MI treated with enalapril; MI treated with BNP+enalapril. Rats were closely monitored for survival rate analysis. Rats from each group were sacrificed on days 3, 7 and 28 postoperation.. The results showed that chronic continuous BNP infusion achieved similar effects to enalapril therapy, as evidenced by improved survival rate within the 28-day observation period compared with MI group rats; this effect was closely associated with preserved cardiac geometry and performance. The treatment combination did not offer extra benefits in terms of survival rate. Both BNP and enalapril therapy produced higher heart tissue concentrations of cyclic guanosine monophosphate and lower expression levels of inflammatory cytokines, including tumour necrosis factor-α, interleukin-1 and interleukin-6. These benefits were associated with lower phosphorylation levels of NF-κB subunits IκBα, p50 and p65. While enalapril significantly inhibited extracellular matrix remodelling via regulation of the protein expression ratio of matrix metalloproteinase/tissue inhibitor of metalloproteinase and the activity of matrix metalloproteinase, these variables were not affected by BNP, indicating that the two therapies involve different mechanisms.. Chronic BNP infusion can provide beneficial effects against adverse post-MI remodelling.

Topics: Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Cardiovascular Agents; Collagen; Cyclic GMP; Disease Models, Animal; Enalapril; Hemodynamics; I-kappa B Proteins; Inflammation Mediators; Infusion Pumps, Implantable; Infusions, Intravenous; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain; NF-kappa B p50 Subunit; NF-KappaB Inhibitor alpha; Phosphorylation; Rats; Rats, Sprague-Dawley; Time Factors; Tissue Inhibitor of Metalloproteinase-1; Transcription Factor RelA; Ventricular Function, Left; Ventricular Remodeling

In this study, the anti-heart failure effect of icariin, a natural flavonol glycoside, and the underlying mechanisms were investigated.. Heart failure was induced by isoproterenol in male Sprague-Dawley rats. Matrix metalloproteinase activity was determined by gelatin zymography assay. The mRNA expression was determined by real-time PCR. The protein expression was determined by Western bolt. Mitochondria structure was examined by transmission electron microscopy.. Isoproterenol administration resulted in a severe heart failure, as shown by the increased levels of left ventricular weight index, heart rate, left ventricular end diastolic pressure, maximal rate of left ventricular pressure decline (dp/dt(min) ), decreased levels of left ventricular systolic pressure and maximal rate of left ventricular pressure rise (dp/dt(max) ). Against these, icariin dose-dependently reversed the changes of these cardiac morphometric and haemodynamic parameters. In addition, icariin significantly inhibited serum levels of tumour necrosis factor-α, noradrenaline, angiotensin II and brain natriuretic peptide in rats with congestive hear failure and improved the histological changes, including cardiocyte hypertrophy, cardiocyte degeneration, inflammatory infiltration and cardiac desmoplasia. Furthermore, the expression and activity of matrix metalloproteinase (MMP)-2 and MMP-9, which regulate collagen production, were also blocked by icariin. Moreover, myocardial apoptosis was remarkably attenuated by icariin through regulating Bcl-2/Bax axle.. Icariin ameliorates left ventricular dysfunction and cardiac remodelling through down-regulating matrix metalloproteinase-2 and 9 activity and myocardial apoptosis in rats with congestive heart failure.

Topics: Angiotensin II; Animals; Apoptosis; Cardiotonic Agents; Disease Models, Animal; Down-Regulation; Flavonoids; Heart Failure; Hemodynamics; Isoproterenol; Male; Matrix Metalloproteinases; Mitochondria; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Norepinephrine; Rats; Rats, Sprague-Dawley; Tumor Necrosis Factor-alpha; Ventricular Remodeling

Chronic myocardial ischaemia (CMI) has become an important cause of heart failure (HF). The aim of this study was to examine the effects of sarco-endoplasmic reticulum calcium ATPase (SERCA2a) gene transfer in large HF animal models induced by CMI.. HF was induced in mini pigs by proximal left anterior descending coronary (LAD) ameroid constrictors. After confirmation of myocardial perfusion defects and cardiac function impairment, animals were divided into 4 groups (each including 4 animals): the HF group; the HF+enhanced green fluorescent protein (EGFP) group; the HF+SERCA2a group; and sham animals as a control group, rAAV1-EGFP and rAAV1-SERCA2a were injected intramyocardially to animals of the HF+EGFP and HF+SERCA2a groups separately. Sixty days after gene transfer, expressions of SERCA2a were examined, cardiac functions and changes of serum inflammatory and neuro-hormonal factors were determined. The results demonstrated that 60 days after gene transfer, LVEF, Ev/Av and +/- dp/dtmax of the HF+SERCA2a group increased significantly (P < 0.05), along with an increase in SERCA2a protein expression (P < 0.05) compared with the HF/HF+EGFP groups. Serum concentrations of inflammatory and neuro-hormonal factors were also decreased in the HF+SERCA2a group (P < 0.05).. Restoration of SERCA2a in myocardium of HF model induced by CMI could significantly improve cardiac function, suggesting its potential therapeutic significance in CMI-related heart failure.

Topics: Adenoviridae; Angiotensin II; Animals; Disease Models, Animal; Endothelin-1; Fluorescent Dyes; Gene Transfer Techniques; Genetic Therapy; Green Fluorescent Proteins; Heart Failure; Interleukin-6; Male; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Stroke Volume; Swine; Swine, Miniature; Tumor Necrosis Factor-alpha

Although oxidative stress is considered to promote arrhythmogenic substrates in diseased model animals, it is difficult to evaluate its primary role. In this study, we evaluated the promotion of arrhythmogenic substrates in the primary hyperoxidative state.. Sprague-Dawley rats were treated with L-buthionine-sulfoximine (BSO, 30 mmol · L(-1) · day(-1)) for 14 days. On day 7 or 14, the serum levels of derivatives of reactive oxygen metabolites (d-ROM) were measured, and immune staining of 8-hydroxy-2'-deoxyguanosine (8O HdG) was performed to assess oxidative stress. The ventricular effective refractory period (ERP), monophasic action potential duration (MAPD), and the inducibility of ventricular arrhythmia were also evaluated. BSO rats exhibited higher serum d-ROM and clearer 8OHdG staining than the controls. The inducibility of ventricular arrhythmia was higher in the BSO rats than in the controls. The ERP was shorter in the BSO rats than the control (day 14, 32 ± 1 vs. 36 ± 1 ms, P<0.05), whereas the MAPD(90) was longer in the BSO rats (day 14, 76 ± 5 vs. 55 ± 4 ms, P<0.05). The mRNA levels of Kv4.2, erg, and SERCA2a were downregulated in the BSO rats (P < 0.05), and Western blot analysis exhibited the downregulation of erg and SERCA2 expression in the BSO rats (P < 0.05).. Systemic oxidative stress might be one of the primary factors promoting cardiac electrophysiological remodeling and increasing the inducibility of arrhythmia independently of major organ disorders.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Action Potentials; Analysis of Variance; Animals; Arrhythmias, Cardiac; Blood Pressure; Blotting, Western; Buthionine Sulfoximine; Cardiac Pacing, Artificial; Cytokines; Deoxyguanosine; Disease Models, Animal; Disease Progression; Ether-A-Go-Go Potassium Channels; Glutathione; Hydrogen Peroxide; Immunohistochemistry; Myocardium; Natriuretic Peptide, Brain; Oxidative Stress; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Shal Potassium Channels; Time Factors; Ventricular Dysfunction; Ventricular Remodeling

Despite the availability of many pharmacological and mechanical therapies, the mortality rate among patients with congestive heart failure (CHF) remains high. We tested the hypothesis that TVP1022 (the S-isomer of rasagiline; Azilect), a neuroprotective and cytoprotective molecule, is also cardioprotective in the settings of experimental CHF in rats.. In rats with volume overload-induced CHF, we investigated the therapeutic efficacy of TVP1022 (7.5 mg/kg) on cardiac function, structure, biomarkers, and kidney function. Treatment with TVP1022 for 7 days before CHF induction prevented the increase in left ventricular end-diastolic area and end-systolic area, and the decrease in fractional shortening measured 14 days after CHF induction. Additionally, TVP1022 pretreatment attenuated CHF-induced cardiomyocyte hypertrophy, fibrosis, plasma and ventricular B-type natriuretic peptide levels, and reactive oxygen species expression. Further, in CHF rats, TVP1022 decreased cytochrome c and caspase 3 expression, thereby contributing to the cardioprotective efficacy of the drug. TVP1022 also enhanced the urinary Na(+) excretion and improved the glomerular filtration rate. Similar cardioprotective effects were obtained when TVP1022 was given to rats after CHF induction.. TVP1022 attenuated the adverse functional, structural, and molecular alterations in CHF, rendering this drug a promising candidate for improving cardiac and renal function in this disease state.

Topics: Animals; Cardiotonic Agents; Caspase 3; Cytochromes c; Disease Models, Animal; Fibrosis; Glomerular Filtration Rate; Heart Failure; Hypertrophy; Indans; Kidney; Myocytes, Cardiac; Natriuretic Peptide, Brain; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Ventricular Remodeling

B-type natriuretic peptide (BNP) is an endogenous peptide produced under physiological and pathological conditions mainly by ventricular myocytes. It has natriuretic, diuretic, blood pressure-lowering, and antifibrotic actions that could mediate cardiorenal protection in cardiovascular diseases. In the present study, we used BNP gene transfer to examine functional and structural effects of BNP on left ventricular (LV) remodeling.. Human BNP was overexpressed by using adenovirus-mediated gene delivery in normal rat hearts and in hearts during the remodeling process after infarction and in an experimental model of angiotensin II-mediated hypertension. In healthy hearts, BNP gene delivery into the anterior wall of the LV decreased myocardial fibrosis (P<0.01, n=7 to 8) and increased capillary density (P<0.05, n=7 to 8) associated with a 7.3-fold increase in LV BNP peptide levels. Overexpression of BNP improved LV fractional shortening by 22% (P<0.05, n=6 to 7) and ejection fraction by 19% (P<0.05, n=6 to 7) after infarction. The favorable effect of BNP gene delivery on cardiac function after infarction was associated with normalization of cardiac sarcoplasmic reticulum Ca(2+)-ATPase expression and phospholamban Thr17-phosphorylation. BNP gene delivery also improved fractional shortening and ejection fraction in angiotensin II-mediated hypertension as well as decreased myocardial fibrosis and LV collagen III mRNA levels but had no effect on angiogenesis or Ca(2+)-ATPase expression and phospholamban phosphorylation.. Local intramyocardial BNP gene delivery improves cardiac function and attenuates adverse postinfarction and angiotensin II-induced remodeling. These results also indicate that myocardial BNP has pleiotropic, context-dependent, favorable actions on cardiac function and suggest that BNP acts locally as a key mechanical load-activated regulator of angiogenesis and fibrosis.

Topics: Adenoviridae; Angiotensin II; Animals; Collagen Type III; Disease Models, Animal; Fibrosis; Gene Transfer Techniques; Genetic Therapy; Humans; Hypertension; Ligation; Male; Myocardial Infarction; Natriuretic Peptide, Brain; Neovascularization, Physiologic; Organothiophosphorus Compounds; Rats; Rats, Sprague-Dawley; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Ventricular Dysfunction, Left; Ventricular Remodeling

Sleep apnea syndrome increases the risk of cardiovascular morbidity and mortality. We previously reported that intermittent hypoxia increases superoxide production in a manner dependent on nicotinamide adenine dinucleotide phosphate and accelerates adverse left ventricular (LV) remodeling. Recent studies have suggested that hydrogen (H(2)) may have an antioxidant effect by reducing hydroxyl radicals. In this study, we investigated the effects of H(2) gas inhalation on lipid metabolism and LV remodeling induced by intermittent hypoxia in mice. Male C57BL/6J mice (n = 62) were exposed to intermittent hypoxia (repetitive cycle of 1-min periods of 5 and 21% oxygen for 8 h during daytime) for 7 days. H(2) gas (1.3 vol/100 vol) was given either at the time of reoxygenation, during hypoxic conditions, or throughout the experimental period. Mice kept under normoxic conditions served as controls (n = 13). Intermittent hypoxia significantly increased plasma levels of low- and very low-density cholesterol and the amount of 4-hydroxy-2-nonenal-modified protein adducts in the LV myocardium. It also upregulated mRNA expression of tissue necrosis factor-α, interleukin-6, and brain natriuretic peptide, increased production of superoxide, and induced cardiomyocyte hypertrophy, nuclear deformity, mitochondrial degeneration, and interstitial fibrosis. H(2) gas inhalation significantly suppressed these changes induced by intermittent hypoxia. In particular, H(2) gas inhaled at the timing of reoxygenation or throughout the experiment was effective in preventing dyslipidemia and suppressing superoxide production in the LV myocardium. These results suggest that inhalation of H(2) gas was effective for reducing oxidative stress and preventing LV remodeling induced by intermittent hypoxia relevant to sleep apnea.

Topics: Administration, Inhalation; Aldehydes; Analysis of Variance; Animals; Cholesterol, LDL; Cholesterol, VLDL; Disease Models, Animal; Dyslipidemias; Fibrosis; Free Radical Scavengers; Gases; Gene Expression Regulation; Heart Diseases; Heart Ventricles; Hemodynamics; Hydrogen; Hypoxia; Interleukin-6; Lipid Metabolism; Male; Mice; Mice, Inbred C57BL; Myocardium; Natriuretic Peptide, Brain; Oxidative Stress; RNA, Messenger; Superoxides; Time Factors; Tumor Necrosis Factor-alpha; Ventricular Remodeling

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

Current rodent models of ischemia/infarct or pressure-volume overload are not fully representative of human heart failure. We developed a new model of congestive heart failure (CHF) with both ischemic and stress injuries combined with fibrosis in the remote myocardium. Sprague-Dawley male rats were used. Ascending aortic banding (Ab) was performed to induce hypertrophy. Two months post-Ab, ischemia-reperfusion (I/R) injury was induced by ligating the left anterior descending (LAD) artery for 30 min. Permanent LAD ligation served as positive controls. A debanding (DeAb) procedure was performed after Ab or Ab + I/R to restore left ventricular (LV) loading properties. Cardiac function was assessed by echocardiography and in vivo hemodynamic analysis. Myocardial infarction (MI) size and myocardial fibrosis were assessed. LV hypertrophy was observed 4 mo post-Ab; however, systolic function was preserved. LV hypertrophy regressed within 1 mo after DeAb. I/R for 2 mo induced a small to moderate MI with mild impairment of LV function. Permanent LAD ligation for 2 mo induced large MI and significant cardiac dysfunction. Ab for 2 mo followed by I/R for 2 mo (Ab + I/R) resulted in moderate MI with significantly reduced ejection fraction (EF). DeAb post Ab + I/R to reduce afterload could not restore cardiac function. Perivascular fibrosis in remote myocardium after Ab + I/R + DeAb was associated with decreased cardiac function. We conclude that Ab plus I/R injury with aortic DeAb represents a novel model of CHF with increased fibrosis in remote myocardium. This model will allow the investigation of vascular and fibrotic mechanisms in CHF characterized by low EF, dilated LV, moderate infarction, near-normal aortic diameter, and reperfused coronary arteries.

Topics: Analysis of Variance; Animals; Aorta; Atrial Natriuretic Factor; Coronary Vessels; Disease Models, Animal; Disease Progression; Fibrosis; Gene Expression Regulation; Heart Failure; Hemodynamics; Hypertension; Hypertrophy, Left Ventricular; Ligation; Male; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley; RNA, Messenger; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Stroke Volume; Time Factors; Ultrasonography; Ventricular Dysfunction, Left; Ventricular Function, Left; Ventricular Pressure

Fractalkine (FKN) is a newly identified membrane-bound chemokine; its role in myocardial ischaemia and heart failure is largely unknown. We attempted to investigate the role of FKN in myocardial ischaemia and ischaemia or pressure overload-induced ventricular remodelling and heart failure.. FKN-induced changes of heart failure-related genes in cultured rat cardiac cells and the effect of FKN on cultured cardiomyocyte injury during anoxia/reoxygenation (A/R) were examined. The direct influence of FKN neutralization on heart failure and the potential mechanism was also investigated. In mice with failing hearts, myocardial FKN expression was correlated with the lung weight/body weight ratio, left ventricular fractional shortening, and brain natriuretic peptide expression. In cultured rat cells, exposure to FKN increased natriuretic peptide A expression in cardiomyocytes, matrix metalloproteinase-9 expression in fibroblasts, and intercellular adhesion molecule-1 expression in microvascular endothelial cells. FKN also promoted cardiomyocyte damage during A/R and neutralizing FKN antibody treatment improved heart failure induced by myocardial infarction or pressure overload. Neutralizing FKN or its receptor inhibited the activation of mitogen-activated protein kinases (MAPKs) in hypoxic cardiomyocytes or ischaemic myocardium.. FKN promotes myocardial injury and accelerates the progress of heart failure, which is associated with the activation of MAPKs.

Topics: Animals; Animals, Newborn; Antibodies, Neutralizing; Atrial Natriuretic Factor; Cells, Cultured; Chemokine CX3CL1; Disease Models, Animal; Endothelial Cells; Enzyme Activation; Fibroblasts; Heart Failure; Intercellular Adhesion Molecule-1; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Mitogen-Activated Protein Kinases; Myocardial Ischemia; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats; Recombinant Proteins; Severity of Illness Index; Time Factors; Ventricular Remodeling

To determine the effect of atorvastatin on rat heart failure after myocardial infarction and to investigate the underlying mechanism of atorvastatin-mediated myocardium protection.. Thirty-eight rats were randomly divided into three groups: a heart failure model group (model group), a heart failure plus atorvastatin treatment group (atorvastatin group) and a sham-surgery group (control group). The rat heart failure model was established by ligation of the left anterior descending of coronary arteries (LADs). Changes in hemodynamics parameters were recorded after the final drug administration. Plasma brain natriuretic peptide (BNP) concentration was determined by enzyme-linked immunosorbent assay (ELISA). Histological diagnosis was achieved by hematoxylin and eosin (H&E) and Masson's trichrome staining. The expressions of 78 kDa glucose-regulated protein 78 (GRP78), caspase-12 and C/EBP homologous protein (CHOP, also known as GADD153) in myocardial cells and cultured cardiac myocytes were examined by Western blot. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was used to evaluate myocardial cell apoptosis, and flow cytometry was performed to examine the cell apoptosis of cultured cardiac myocytes.. In the atorvastatin group, myocardial cells were lined up more orderly and myocardial fibrosis level was decreased compared to the model group. The expressions of GRP78, caspase-12 and CHOP in myocardial cells were decreased in atorvastatin group. Moreover, in the atorvastatin-treated group the cell apoptosis rate was reduced and the endoplasmic reticulum (ER) stress was activated in response to heart failure and angiotensin II (Ang II) stimulation.. By down-regulating GRP78, caspase-12 and CHOP expressions in myocardial cells in rat heart failure after myocardial infarction, atorvastatin treatment decreased the apoptosis of myocardial cells, suggesting the possible mechanism by which atorvastatin functions in protecting against heart failure.

Topics: Animals; Apoptosis; Atorvastatin; Caspase 12; Cells, Cultured; Disease Models, Animal; Endoplasmic Reticulum Stress; Female; Heart Failure; Heat-Shock Proteins; Heptanoic Acids; Hydroxymethylglutaryl-CoA Reductase Inhibitors; In Situ Nick-End Labeling; Myocardial Infarction; Natriuretic Peptide, Brain; Pyrroles; Rats; Rats, Wistar; Transcription Factor CHOP

Preventing Ca(2+)-leak during diastole may provide a means to improve overall cardiac function. The immunosuppressant FK506-binding protein 12.6 (FKBP12.6) regulates ryanodine receptor-2 (RyR2) gating and binds to and inhibits calcineurin (Cn). It is also involved in the pathophysiology of heart failure (HF). Here, we investigated the effects of FKBP12.6 over-expression and gender on Ca(2+)-handling proteins (RyR2, SERCA2a/PLB, and NCX), and on pro-(CaMKII, Cn/NFAT) and anti-hypertrophic (GSK3β) signalling pathways in a thoracic aortic constriction (TAC) mouse model. Wild type mice (WT) and mice over-expressing FKBP12.6 of both genders underwent TAC or sham-operation (Sham). FKBP12.6 over-expression ameliorated post-TAC survival rates in both genders. Over time, FKBP12.6 over-expression reduced the molecular signature of left ventricular hypertrophy (LVH) and the transition to HF (BNP and β-MHC mRNAs) and attenuated Cn/NFAT activation in TAC-males only. The gender difference in pro- and anti-hypertrophic LVH signals was time-dependent: TAC-females exhibited earlier pathological LVH associated with concomitant SERCA2a down-regulation, CaMKII activation, and GSK3β inactivation. Both genotypes showed systolic dysfunction, possibly related to down-regulated RyR2, but only FK-TAC-males exhibited preserved diastolic LV function. Although FKBP12.6 over-expression did not impact the vicious cycle of TAC-induced HF, this study reveals some subtle sequential and temporal gender differences in Ca(2+)-signalling pathways of pathological LVH.

Topics: Animals; Aorta, Thoracic; Calcineurin Inhibitors; Calcium; Calcium Signaling; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Calcium-Calmodulin-Dependent Protein Kinases; Disease Models, Animal; Down-Regulation; Female; Gene Expression Profiling; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Heart; Heart Failure; Homeodomain Proteins; Humans; Hypertrophy, Left Ventricular; Major Histocompatibility Complex; Male; Mice; Mice, Transgenic; Natriuretic Peptide, Brain; Phenotype; Random Allocation; Ryanodine Receptor Calcium Release Channel; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Sex Factors; Signal Transduction; Tacrolimus Binding Proteins; Ventricular Pressure

Activated vitamin D analog, paricalcitol, has been shown to attenuate the development of cardiac hypertrophy in Dahl salt sensitive (DSS) rats. To determine whether an antihypertrophic effect is class specific, we tested if doxercalciferol (a pro-hormone vitamin D2 analog) could also attenuate the development of cardiac hypertrophy in DSS rats.. Male DSS rats were fed a high salt (HS) diet for 6 weeks beginning at 6 weeks of age. Doxercalciferol was administered intraperitoneally at 150 ng, 3 times per week (Monday, Wednesday, Friday) for 6 weeks. Pathological and echocardiographic findings demonstrated that rats on HS diet with doxercalciferol administration had significant decrease in cardiac hypertrophy and improved cardiac function compared to the HS + vehicle. In addition, there was a significant decrease in plasma brain natriuretic peptide (BNP) level and tissue atrial natriuretic factor (ANF) mRNA level with doxercalciferol treatment. Doxercalciferol also significantly reduced the level of protein kinase C-α (PKCα) suggesting that PKC-mediated cardiac hypertrophy may be associated with vitamin D deficiency.. Administration of doxercalciferol attenuated the development of HS diet induced cardiac hypertrophy and cardiac dysfunction in DSS rats.

Topics: Animals; Atrial Natriuretic Factor; Disease Models, Animal; Ergocalciferols; Heart Failure; Hypertrophy, Left Ventricular; Male; Natriuretic Peptide, Brain; Rats; Rats, Inbred Dahl; RNA, Messenger; Signal Transduction; Ultrasonography; Vitamins

Uremic cardiomyopathy contributes substantially to mortality in chronic kidney disease (CKD) patients. Glucagon-like peptide-1 (GLP-1) may improve cardiac function, but is mainly degraded by dipeptidyl peptidase-4 (DPP-4).. In a rat model of chronic renal failure, 5/6-nephrectomized [5/6N] rats were treated orally with DPP-4 inhibitors (linagliptin, sitagliptin, alogliptin) or placebo once daily for 4 days from 8 weeks after surgery, to identify the most appropriate treatment for cardiac dysfunction associated with CKD. Linagliptin showed no significant change in blood level AUC(0-∞) in 5/6N rats, but sitagliptin and alogliptin had significantly higher AUC(0-∞) values; 41% and 28% (p = 0.0001 and p = 0.0324), respectively. No correlation of markers of renal tubular and glomerular function with AUC was observed for linagliptin, which required no dose adjustment in uremic rats. Linagliptin 7 µmol/kg caused a 2-fold increase in GLP-1 (AUC 201.0 ng/l*h) in 5/6N rats compared with sham-treated rats (AUC 108.6 ng/l*h) (p = 0.01). The mRNA levels of heart tissue fibrosis markers were all significantly increased in 5/6N vs control rats and reduced/normalized by linagliptin.. DPP-4 inhibition increases plasma GLP-1 levels, particularly in uremia, and reduces expression of cardiac mRNA levels of matrix proteins and B-type natriuretic peptides (BNP). Linagliptin may offer a unique approach for treating uremic cardiomyopathy in CKD patients, with no need for dose-adjustment.

Topics: Animals; Area Under Curve; Cardiomyopathies; Dipeptidyl Peptidase 4; Dipeptidyl-Peptidase IV Inhibitors; Disease Models, Animal; Gene Expression Regulation; Glomerular Filtration Rate; Glucagon-Like Peptide 1; Heart; Humans; Kidney Failure, Chronic; Linagliptin; Myocardium; Natriuretic Peptide, Brain; Nephrectomy; Piperidines; Purines; Pyrazines; Quinazolines; Rats; Reverse Transcriptase Polymerase Chain Reaction; Sitagliptin Phosphate; Triazoles; Uracil; Uremia

To evaluate the therapeutic effect of hBNP on rats with chronic heart failure (CHF).. Thirty CHF rats defined by echocardiography at 12 weeks post abdominal aortic constriction were randomly divided into Ad-hBNP group (2.5 × 10(10) VP/ml NS Ad-hBNP 1 ml/week × 4, n = 14), Ad-Track group (n = 8), placebo group (NS, n = 8), 10 sham-operated rats served as control group. After 4 weeks treatment, cardiac function was evaluated by echocardiography and hemodynamic measurements. Heart weight (HW) and HW/body weight (BW) ratio were determined.. IVS, LVPW, LVEDD and LVESD were significantly reduced in the Ad-hBNP group [(2.34 ± 0.29) mm, (2.28 ± 0.18) mm, (6.50 ± 0.42) mm, (3.54 ± 0.59) mm] than those in the Ad-Track group [(2.71 ± 0.35) mm, (3.02 ± 0.85) mm, (7.71 ± 0.83) mm, (4.72 ± 0.80) mm] and in the NS group [(2.78 ± 0.23) mm, (2.83 ± 0.53) mm, (7.34 ± 0.97) mm, (4.55 ± 0.77) mm, all P < 0.05]. The LVEF and LVFS of the Ad-hBNP group [(79.27 ± 7.01)%, (43.38 ± 6.73)%] were significantly higher than in the Ad-Track group [(70.85 ± 4.81)%, (35.72 ± 3.68)%] and in the NS group [(69.67 ± 6.90)%, (34.91 ± 5.10)%, all P < 0.01]. HR [(417.48 ± 32.57) beats/min, (446.85 ± 61.49) beats/min, P < 0.05; (440.83 ± 32.18) beats/min, P < 0.05], LVEDP [(-4.24 ± 4.00) mm Hg (1 mm Hg = 0.133 kPa); (21.99 ± 6.80) mm Hg, P < 0.01; (18.00 ± 12.25) mm Hg, P < 0.01] were significantly decreased and while LVSP [(131.79 ± 15.76) mm Hg; (112.99 ± 32.35) mm Hg, P < 0.05; (117.13 ± 15.26) mm Hg], +dP/dt(max) [(5037.20 ± 430.41) mm Hg/s; (4217.40 ± 1354.15) mm Hg/s, P < 0.05; (4310.50 ± 1293.97) mm Hg/s, P < 0.05] and -dP/dt(max) [(-4382.00 ± 1304.79) mm Hg/s; (-3725.00 ± 791.34) mm Hg/s, P < 0.05; (-3890.00 ± 1043.73) mm Hg/s, P < 0.05]were significantly increased in Ad-hBNP group than in Ad-Track group and NS group (all P < 0.05). HW and HW/BW were also decreased in Ad-hBNP group than in the Ad-Track group and the NS group.. Exogenous hBNP improved the cardiac function and attenuated remodeling in CHF rats.

Topics: Adenoviridae; Animals; Disease Models, Animal; Heart Failure; Hemodynamics; Male; Natriuretic Peptide, Brain; Random Allocation; Rats; Rats, Wistar

There is emerging evidence to suggest that brain natriuretic peptide (BNP) is elevated after acute brain injury, and that it may play an adaptive role in recovery through augmentation of cerebral blood flow (CBF). Through a series of experiments, we tested the hypothesis that the administration of BNP after different acute mechanisms of central nervous system (CNS) injury could improve functional recovery by improving CBF. C57 wild-type mice were exposed to either pneumatic-induced closed traumatic brain injury (TBI) or collagenase-induced intracerebral hemorrhage (ICH). After injury, either nesiritide (hBNP) (8 microg/kg) or normal saline were administered via tail vein injection at 30 min and 4 h. The mice then underwent functional neurological testing via rotorod latency over the following 5 days and neurocognitive testing via Morris water maze testing on days 24-28. Cerebral blood flow (CBF) was assessed by laser Doppler from 25 to 90 min after injury. After ICH, mRNA polymerase chain reaction (PCR) and histochemical staining were performed during the acute injury phase (<24 h) to determine the effects on inflammation. Following TBI and ICH, administration of hBNP was associated with improved functional performance as assessed by rotorod and Morris water maze latencies (p < 0.01). CBF was increased (p < 0.05), and inflammatory markers (TNF-alpha and IL-6; p < 0.05), activated microglial (F4/80; p < 0.05), and neuronal degeneration (Fluoro-Jade B; p < 0.05) were reduced in mice receiving hBNP. hBNP improves neurological function in murine models of TBI and ICH, and was associated with enhanced CBF and downregulation of neuroinflammatory responses. hBNP may represent a novel therapeutic strategy after acute CNS injury.

Topics: Acute Disease; Animals; Brain; Brain Injuries; Cerebral Hemorrhage; Cerebrovascular Circulation; Cognition Disorders; Cytokines; Disease Models, Animal; Fluoresceins; Male; Maze Learning; Mice; Mice, Inbred C57BL; Natriuretic Agents; Natriuretic Peptide, Brain; Nerve Degeneration; Nerve Regeneration; Neuroprotective Agents; Organic Chemicals; Recovery of Function; RNA, Messenger; Time Factors; Treatment Outcome

The effects of exogenous B-type natriuretic peptide (BNP) on postmyocardial infarction (MI) are not known. We tested the hypothesis that in vivo infusion of BNP would improve cardiac function and affect left ventricular (LV) remodeling in an experimental model of MI.. MI was induced by coronary ligation in rats and confirmed by echocardiography. 19 rats were randomized to 1 of 3 groups: sham (n = 7), MI + saline (n = 5), MI + BNP (400 ng.kg(-1).minute(-1)) (n = 7). Infusions were delivered for 7 days via venous catheters tunneled to an infusion pump. Rats were followed for 8 weeks. Echocardiography, hemodynamics, histology, and in vivo and ex vivo pressure-volume relationships were examined.. LV systolic pressure, LV dP/dtmax, and infarct size improved with BNP treatment versus control MI group (132 +/- 4 vs.110 +/- 2 mm Hg, 8097 +/- 317 vs. 5816 +/- 378 mm Hg/s, 19.3% +/- 1.6% vs. 23.3% +/- 1.9%, respectively; all P < 0.05). Ex vivo end-diastolic pressure-volume relationship demonstrated reduced diastolic dysfunction after BNP therapy (P < 0.05 vs. control MI). Serum BNP levels confirmed delivery of BNP.. We demonstrate beneficial effects on LV function and decreased LV remodeling with BNP infusion in an experimental model of acute MI.

Topics: Animals; Disease Models, Animal; Echocardiography; Myocardial Infarction; Natriuretic Agents; Natriuretic Peptide, Brain; Random Allocation; Rats; Rats, Sprague-Dawley; Ventricular Function, Left; Ventricular Remodeling

Chronic treatment with suprapharmacologic doses of peroxisome proliferator-activated receptor (PPAR) agonists has a known potential for causing left ventricular hypertrophy (LVH). The mechanism by which LVH develops is not well understood nor are biomarkers of it well characterized. Natriuretic peptides are important regulators of cardiac growth, blood volume, and arterial pressure and may be useful biomarkers of LVH and hemodynamic changes that precede it. We measured amino-terminal pro-atrial natriuretic peptide (NTproANP), amino-terminal pro-brain natriuretic peptide (NTproBNP), and cardiac troponin I (cTnI) concentrations in serum and plasma, as well as transcripts in left ventricular heart tissue for atrial natriuretic peptide precursor (Nppa), brain natriuretic peptide precursor (Nppb), and myosin heavy chain-beta (Myh7) as potential biomarkers of LVH induced by a PPARalpha/gamma dual agonist in Sprague-Dawley rats. We used magnetic resonance imaging, echocardiography, and hemodynamics to identify structural and functional cardiovascular changes related to the biomarkers. Heart-to-brain weight ratios (HW:BrW) were correlated with NTproANP, NTproBNP, and cTnI concentrations in serum as well as fold change in expression of Nppa and Nppb. LVH was characterized by increased left ventricular wall thickness and inner diameter, increased cardiac output, decreased arterial blood pressure, and increased heart rate. In these studies, each end point contributed to the early detection of LVH, the ability to monitor its progression, and demonstrated the ability of NTproANP concentration in serum to predict LVH and hemodynamic changes.

Topics: Animals; Atrial Natriuretic Factor; Biomarkers; Cardiovascular Agents; Disease Models, Animal; Echocardiography; Female; Heart; Hypertrophy, Left Ventricular; Magnetic Resonance Imaging; Male; Myocardium; Natriuretic Peptide, Brain; Organ Size; Peptide Fragments; Phenylpropionates; PPAR alpha; PPAR gamma; Rats; Rats, Sprague-Dawley; Signal Transduction; Thiophenes; Troponin T

Lipocalin-2/neutrophil gelatinase-B associated lipocalin (Lcn2/NGAL) is involved in the transport of iron and seems to play an important role in inflammation. A recent study has reported that it is also expressed in the failing heart and may be a biomarker not only for renal failure but also for heart failure. Because Lcn2/NGAL is thought to be induced by interleukin-1, it might be strongly induced in the presence of myocarditis.. This study investigated the expression of Lcn2/NGAL in rat experimental autoimmune myocarditis (EAM) and in human myocarditis. In EAM hearts, the expression of Lcn2/NGAL was markedly increased (>100-fold at an early stage), and in human myocarditis it was also highly expressed compared with non-inflammatory failing hearts. Lcn2/NGAL expressing cells in hearts with EAM and human myocarditis were identified as cardiomyocytes, vascular wall cells, fibroblasts and neutrophils. Lcn2/NGAL in EAM rats was also expressed in the liver. Plasma Lcn2/NGAL levels abruptly increased at an early stage of EAM, and high levels were initially sustained during the inflammatory stage, then decreased with recovery. In contrast, levels of B-type natriuretic peptide increased only slowly as the disease progressed.. Cardiomyocytes, vascular wall cells and fibroblasts in myocarditis strongly express Lcn2/NGAL via proinflammatory cytokines.

Topics: Acute-Phase Proteins; Aged; Animals; Autoimmune Diseases; Disease Models, Animal; Female; Fibroblasts; Gene Expression; Heart Failure; Humans; Immunization; Interleukin-1beta; Lipocalin-2; Lipocalins; Male; Matrix Metalloproteinase 9; Middle Aged; Myocarditis; Myocytes, Cardiac; Myosins; Natriuretic Peptide, Brain; Proto-Oncogene Proteins; Rats; Swine; Young Adult

Hemodynamic parameters and natriuretic peptide levels were evaluated in cardiac hypertrophy produced by sequentially applied renovascular (RV) and deoxycorticosterone acetate-salt (DS) models of hypertension. We studied hypertensive rats by RV or DS treatment at 2 and 4 wk, as well as by the combination of 2 wk of each treatment in an inverse sequence: RV 2 wk/DS 2 wk (RV2/DS2) and DS 2 wk/RV 2 wk (DS2/RV2). The in vivo cardiac function, interstitial fibrosis, and synthesis and secretion of types A (ANP) and B (BNP) natriuretic peptides were monitored in hypertensive models compared with their corresponding sham (Sh2, Sh4). There were no differences in relaxation parameters among RV or DS groups and combined treatments. Left ventricular +dP/dt(max) increased only in RV4 (P < 0.01 vs. Sh4), and this increase was abolished in RV2/DS2. Interstitial collagen concentration increased after 4 wk in both RV4 and RV2/DS2 groups. Although there were no changes in collagen concentration in either DS2 or DS4 groups, clipping after 2 wk of DS (DS2/RV2) remarkably stimulated interstitial fibrosis (P < 0.01 vs. DS2). Plasma BNP increased in RV treatment at 4 wk (P < 0.001 vs. Sh4), but not in DS. Interestingly, RV applied after the 2 wk of DS treatment induced a marked increase in BNP levels (P < 0.001 vs. Sh4). In this regard, plasma BNP appears to be a reliable indicator of pressure overload. Our results suggest that the second stimulus of mechanical overload in combined models of hypertension determines the evolution of hypertrophy and synthesis and secretion of ANP and BNP.

Topics: Animals; Atrial Natriuretic Factor; Biomechanical Phenomena; Blood Pressure; Collagen; Desoxycorticosterone; Disease Models, Animal; Hypertension; Hypertension, Renovascular; Male; Natriuretic Peptide, Brain; Natriuretic Peptides; Rats; Rats, Sprague-Dawley; Ventricular Function, Left

According to the European recommendations rodents should be provided with a nest box if there is insufficient nesting material to build a complete, covered nest. Rats are generally poor nest builders; hence an additional structure is needed. Optimally, housing refinement may be combined with better science; at least it should not detract from the scientific integrity. In order to evaluate these options, there is a need to assess the items used in individual research projects. Studies investigating molecular mechanisms of cardiac hypertrophy and heart failure are typically long-lasting studies; therefore, refinement of the housing of rats in these studies is important. The aim of this study was to evaluate in rats whether a wooden tube has any impact on cardiac morphology or on basal gene expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP); known markers of cardiac overload, hypertrophy and heart failure. The experimental protocol simulated cardiovascular studies, but without any surgical operations. A total of 42 male Hsd:SD rats were used in an eight-week experiment. After weaning, the experimental group was provided with a rectangular aspen tube and nesting material, and the control group with only nesting material. ANP and BNP gene expression were measured from the left ventricles with Northern blot analysis postmortem along with the absolute weights of the whole heart, left and right atria and left and right chambers. The weights of the whole heart and left chamber were also analysed in relation to body weight. No statistically significant differences were observed in any of these variables. The inter-individual variation was also unchanged by the cage item. In conclusion, the aspen tube does not disrupt research results or alter the number of animals needed and can therefore be recommended for enrichment purposes in cardiovascular studies.

Topics: Animals; Atrial Natriuretic Factor; Blotting, Northern; Disease Models, Animal; Gene Expression; Gene Expression Profiling; Heart; Heart Ventricles; Housing, Animal; Male; Myocardium; Natriuretic Peptide, Brain; Organ Size; Rats; Rats, Sprague-Dawley; RNA, Messenger

Hemodynamic and neurohumoral function can affect the efficacy of diuretic therapy in congestive heart failure. Arginine vasopressin increases water reabsorption through the V(2) receptor in the collecting duct, whereas B-type natriuretic peptide (BNP) decreases sodium reabsorption in the collecting duct. We hypothesized that combining BNP to the V(2)-receptor antagonist tolvaptan (TLV) would enhance renal excretory function by augmenting sodium excretion together with aquaresis without adversely affecting renal hemodynamics in experimental congestive heart failure.. Congestive heart failure was induced in 3 groups (n=6 per group) of dogs by tachypacing. A acute experiment was done after 10 days. After baseline measurements, study groups received a 0.1 mg/kg IV bolus of TLV alone (TLV), TLV in combination with BNP (TLV+BNP; 50 ng/[kg . min]), or BNP alone (BNP). Mean arterial pressure increased with TLV, remained unchanged with TLV+BNP, and decreased with BNP (+5+/-1mm Hg versus -1+/-1 mm Hg versus -15+/-1 mm Hg; P<0.05). Renal blood flow and glomerular filtration rate were preserved with all regimens. Urine flow increased in all 3 groups but significantly more so with TLV+BNP (TLV: +0.4+/-0.1 mL/min versus TLV+BNP: +2.4+/-0.5 mL/min versus BNP: +0.8+/-0.3 mL/min; P<0.05). Only TLV+BNP and BNP were natriuretic (P<0.05), whereas only TLV and TLV+BNP increased electrolyte-free water excretion (P<0.05). Compared with TLV alone, TLV+BNP prevented an increase in aldosterone (P<0.05).. Coadministration of TLV and BNP in experimental HF resulted in a beneficial profile of renal, neurohumoral, and hemodynamic actions, specifically potent diuresis with natriuresis, neutral effect on mean arterial pressure, and lack of aldosterone activation.

Topics: Aldosterone; Animals; Benzazepines; Blood Pressure; Disease Models, Animal; Dogs; Drug Therapy, Combination; Glomerular Filtration Rate; Heart Failure; Male; Natriuretic Agents; Natriuretic Peptide, Brain; Receptors, Vasopressin; Renal Circulation; Tolvaptan; Water-Electrolyte Balance

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a multiple ligand receptor induced by oxidative stress. However, its role in chronic heart failure remains unknown.. The left ventricular (LV) expression of LOX-1 was examined in a salt-sensitive Dahl rat model of hypertension. Compared with controls, LOX-1 mRNA levels increased by 4.7-fold in the LV with hypertrophy, and by 32-fold in the LV with decreased systolic function. LV LOX-1 mRNA levels strongly correlated with the decrease in LV ejection fraction (EF) (r=-0.772), and with increases in the LV mRNA levels of B-type natriuretic peptide (r=0.814), monocyte chemoattractant protein-1 (r=0.943), transforming growth factor-beta(1) (r=0.936), and a macrophage marker, F4/80 (r=0.560). Serum levels of soluble LOX-1 were significantly elevated in patients with LV systolic dysfunction and hypertrophy, and significantly correlated with the decrease in EF (r=-0.495).. Marked increase in the LV expression of LOX-1 in failing hearts may contribute to increased serum levels, and might be involved in chronic inflammation during the development of heart failure.

Topics: Aged; Animals; Chemokine CCL2; Cross-Sectional Studies; Disease Models, Animal; Female; Heart Failure; Heart Ventricles; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Middle Aged; Natriuretic Peptide, Brain; Oxidative Stress; Rats; Rats, Inbred Dahl; RNA, Messenger; Scavenger Receptors, Class E; Ventricular Dysfunction, Left

Atrial and brain natriuretic peptides (ANP and BNP, respectively) exert antihypertrophic effects in the heart via their common receptor, guanylyl cyclase (GC)-A, which catalyzes the synthesis of cGMP, leading to activation of protein kinase (PK)G. Still, much of the network of molecular mediators via which ANP/BNP-GC-A signaling inhibit cardiac hypertrophy remains to be characterized.. We investigated the effect of ANP-GC-A signaling on transient receptor potential subfamily C (TRPC)6, a receptor-operated Ca(2+) channel known to positively regulate prohypertrophic calcineurin-nuclear factor of activated T cells (NFAT) signaling.. In cardiac myocytes, ANP induced phosphorylation of TRPC6 at threonine 69, the PKG phosphorylation site, and significantly inhibited agonist-evoked NFAT activation and Ca(2+) influx, whereas in HEK293 cells, it dramatically inhibited agonist-evoked TRPC6 channel activity. These inhibitory effects of ANP were abolished in the presence of specific PKG inhibitors or by substituting an alanine for threonine 69 in TRPC6. In model mice lacking GC-A, the calcineurin-NFAT pathway is constitutively activated, and BTP2, a selective TRPC channel blocker, significantly attenuated the cardiac hypertrophy otherwise seen. Conversely, overexpression of TRPC6 in mice lacking GC-A exacerbated cardiac hypertrophy. BTP2 also significantly inhibited angiotensin II-induced cardiac hypertrophy in mice.. Collectively, these findings suggest that TRPC6 is a critical target of antihypertrophic effects elicited via the cardiac ANP/BNP-GC-A pathway and suggest TRPC6 blockade could be an effective therapeutic strategy for preventing pathological cardiac remodeling.

Topics: Anilides; Animals; Atrial Natriuretic Factor; Calcium Channels; Cells, Cultured; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Disease Models, Animal; Humans; Hypertrophy; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; NFATC Transcription Factors; Patch-Clamp Techniques; Rats; Receptors, Atrial Natriuretic Factor; Signal Transduction; Thiadiazoles; TRPC Cation Channels; TRPC6 Cation Channel

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 blood pressure-lowering effect of the renin inhibitor aliskiren equals that of angiotensin-converting enzyme (ACE) inhibitors and angiotensin (Ang) II type 1 (AT1) receptor blockers. Whether aliskiren offers end-organ protection remains to be investigated. Here, we compared the cardiac effects of aliskiren, the AT1 receptor blocker irbesartan and the ACE inhibitor captopril in spontaneously hypertensive rats (SHR) at equi-hypotensive doses.. SHR were treated for 1-3 weeks with vehicle, aliskiren, captopril or irbesartan (100, 3 and 15 mg/kg per day, respectively) using an osmotic minipump, and compared to vehicle-treated Wistar-Kyoto (WKY) controls. All drugs lowered (but not normalized) mean arterial pressure in SHR equi-effectively, as monitored by radiotelemetry, without altering heart rate. All drugs also reduced the increased cardiomyocyte area in SHR, and tended to normalize the elevated brain natriuretic peptide plasma levels. In the Langendorff set-up, all drugs normalized the diminished endothelium-dependent vasodilator response to bradykinin in SHR. Moreover, aliskiren and irbesartan, but not captopril, decreased the enhanced coronary Ang II response in SHR. Aliskiren reduced plasma renin activity and the plasma and tissue angiotensin levels at 1 week of treatment; yet, after 3 weeks of aliskiren treatment only the cardiac angiotensin levels remained suppressed, whereas no tissue angiotensin reductions were seen with captopril or irbesartan.. For a given decrease in blood pressure, aliskiren improves coronary endothelial function and decreases cardiac hypertrophy in SHR to at least the same degree as ACE inhibition and AT1 receptor blockade. In addition, aliskiren diminishes the enhanced Ang II response in the coronary circulation of SHR and offers superior long-term cardiac angiotensin suppression.

Topics: Amides; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Angiotensins; Animals; Biphenyl Compounds; Blood Pressure; Captopril; Disease Models, Animal; Dose-Response Relationship, Drug; Fumarates; Heart; Heart Ventricles; Hypertension; Hypertrophy; Irbesartan; Male; Natriuretic Peptide, Brain; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Renin; Tetrazoles

Darbepoetin, a long-acting erythropoietin derivative, attenuates cardiomyocyte apoptosis and improves short-term (3 days) cardiac function, but the mechanisms responsible are unknown. We investigated potential mechanisms by which darbepoetin exerts cardioprotection following myocardial infarction in mice and the significance of the erythropoietin receptor (EPOR)-common beta-chain (c-beta-chain) heteroreceptor.. Mice underwent 60 min coronary occlusion followed by treatment with vehicle or a single dose of darbepoetin. Effects on gene expression, apoptosis and neutrophil accumulation in infarcted left ventricle were assessed 24 h later. Cardiac function, effects on vascularization and fibrosis were assessed 28 days later. The significance of EPOR-c-beta-chain heteroreceptor was examined 28 days after infarction using mice deficient in c-beta-chain.. Twenty-four hours after darbepoetin, mRNAs encoding haeme oxygenase-1 (HO-1), iNOS and brain natriuretic peptide (BNP) were markedly elevated only in infarcted regions, and the frequency of apoptotic cells attenuated. Inflammation was also attenuated with reductions in neutrophil numbers. Darbepoetin also elevated mRNAs encoding angiogenic factors: placental growth factor, monocyte chemoattractant protein-1 and interleukin-1beta. Twenty-eight days after treatment, CD31+ vessels in the infarct zone doubled and fibrosis reduced. Cardiac haemodynamics were improved. Darbepoetin also improved cardiac haemodynamics in c-beta-chain-deficient mice, increased HO-1 and iNOS expression and vessel numbers and attenuated fibrosis.. Darbepoetin stimulates expression of haeme oxygenase, iNOS, BNP and angiogenic factors specifically in infarcted left ventricle that attenuates inflammation, apoptosis and fibrosis; elevate vessel numbers; and improve cardiac function. The EPOR-c-beta-chain heteroreceptor is not essential for these effects.

Topics: Animals; Apoptosis; Cardiotonic Agents; Darbepoetin alfa; Disease Models, Animal; Dose-Response Relationship, Drug; Erythropoietin; Fibrosis; Gene Expression Regulation; Heme Oxygenase-1; Hemodynamics; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain; Neovascularization, Physiologic; Neutrophil Infiltration; Nitric Oxide Synthase Type II; Receptors, Erythropoietin; Time Factors; Ventricular Function, Left

This study aimed to test the feasibility of spironolactone treatment in comparison with a surfactant in the early stage of acute respiratory distress syndrome (ARDS) in rats, as assessed by the acute lung injury (ALI) score, blood gas, brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP).. A total of 40 rats were randomly allocated into one of five groups (n is eight). The baseline group (Group B) was subjected to neither tracheotomy nor ARDS induction, while the sham group (Group N) was subjected to tracheotomy upon ARDS induction by acid aspiration. The other three groups were administered either a single dose of spironolactone (100 mg/kg, Group Sp) or surfactant (100 mg/kg, Group S), or were untreated (Group A). Blood samples were collected from the femoral artery for blood gases, BNP and NT-proBNP measurements.. ARDS induction decreased the blood PO2 /FiO2 ratio and increased the BNP and NT-proBNP levels (p is less than 0.001). Compared with the ARDS-untreated group, spironolactone treatment was more effective at reducing the elevated BNP (72 percent versus 37 percent) and NT-proBNP (53 percent versus 23 percent) levels and ALI score (28 percent versus 7 percent) than surfactant treatment. Moreover, the blood PO2 / FiO2 ratio was negatively correlated with the BNP (r is -0.79), NT-proBNP (r is -0.85) and ALI scores (r is -0.85).. Spironolactone is an effective form of treatment for ARDS at an early stage, as reflected by an increased blood O2 /FiO2 ratio, decreased BNP and NT-proBNP levels, and ALI score.

Topics: Acute Lung Injury; Animals; Blood Gas Analysis; Disease Models, Animal; Lung; Male; Mineralocorticoid Receptor Antagonists; Natriuretic Peptide, Brain; Oxygen; Rats; Rats, Sprague-Dawley; Respiratory Distress Syndrome; Spironolactone; Surface-Active Agents; Treatment Outcome

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

Topics: Adult; Anemia, Hemolytic, Congenital; Anemia, Sickle Cell; Animals; Biomarkers; Cardiac Catheterization; Clinical Trials as Topic; Disease Models, Animal; Humans; Hypertension, Pulmonary; Male; Mice; Natriuretic Peptide, Brain; Nitric Oxide; Peptide Fragments; Priapism; Risk Factors; Treatment Failure; Tricuspid Valve Insufficiency; Ultrasonography

B-type natriuretic peptide (BNP) has been known to be secreted from cardiac myocytes and activate its receptor, natriuretic peptide receptor-A (NPR-A), to reduce ventricular fibrosis. However, the function of BNP/NPR-A pathway in the somatic sensory system has been unknown. In the present study, we report a novel function of BNP in pain modulation. Using microarray and immunoblot analyses, we found that BNP and NPR-A were expressed in the dorsal root ganglion (DRG) of rats and upregulated after intraplantar injection of complete Freund's adjuvant (CFA). Immunohistochemistry showed that BNP was expressed in calcitonin gene-related peptide (CGRP)-containing small neurons and IB4 (isolectin B4)-positive neurons, whereas NPR-A was present in CGRP-containing neurons. Application of BNP reduced the firing frequency of small DRG neurons in the presence of glutamate through opening large-conductance Ca2+-activated K+ channels (BKCa channels). Furthermore, intrathecal injection of BNP yielded inhibitory effects on formalin-induced flinching behavior and CFA-induced thermal hyperalgesia in rats. Blockade of BNP signaling by BNP antibodies or cGMP-dependent protein kinase (PKG) inhibitor KT5823 [(9S,10R,12R)-2,3,9,10,11,12-hexahydro-10-methoxy-2,9-dimethyl-1-oxo-9,12-epoxy-1H-diindolo[1,2,3-fg:3',2',1'-kl]pyrrolo[3,4-i][1,6]benzodiazocine-10-carboxylic acid methyl ester] impaired the recovery from CFA-induced thermal hyperalgesia. Thus, BNP negatively regulates nociceptive transmission through presynaptic receptor NPR-A, and activation of the BNP/NPR-A/PKG/BKCa channel pathway in nociceptive afferent neurons could be a potential strategy for inflammatory pain therapy.

Topics: Analysis of Variance; Animals; Antibodies; Biophysical Phenomena; Calcitonin Gene-Related Peptide; Carbazoles; Disease Models, Animal; Dose-Response Relationship, Drug; Double-Blind Method; Enzyme Inhibitors; Excitatory Postsynaptic Potentials; Freund's Adjuvant; Ganglia, Spinal; Gene Expression Regulation; Glutamic Acid; Hyperalgesia; Inflammation; Lectins; Male; Membrane Potentials; Natriuretic Peptide, Brain; Pain; Pain Measurement; Patch-Clamp Techniques; Peptides; Rats; Rats, Sprague-Dawley; Receptors, Atrial Natriuretic Factor; Sensory Receptor Cells; Signal Transduction; Time Factors

Heart failure is characterised by reduced expression of sarcoplasmic reticulum calcium-ATPase (SERCA) and increased expression of B-type natriuretic peptide (BNP). The present study was performed to investigate causality of this inverse relationship under in vivo conditions in the transversal aortic constriction mouse model (TAC). Left ventricular SERCA-mRNA expression was significantly upregulated in TAC by 32% after 6 h, but not different from sham after 24 h. Serum proANP and BNP levels were increased in TAC after 24 h (BNP +274%, p < 0.01; proANP +60%, p < 0.05), but only proANP levels were increased after 6 h (+182%, p < 0.01). cGMP levels were only increased 24 h after TAC (+307%, p < 0.01), but not 6 h after TAC. BNP infusion inhibited the increase in SERCA expression 6 h after TAC. In BNP-receptor-knockout animals (GC-A), the expression of SERCA was still significantly increased 24 h after TAC at the mRNA level by 35% (p < 0.05), as well as at the protein level by 25% (p < 0.05). MCIP expression as an indicator of calcineurin activity was regulated in parallel to SERCA after 6 and 24 h. MCIP-mRNA was increased by 333% 6 h after TAC, but not significantly different from sham after 24 h. In the GC-A-KO mice, MCIP-mRNA was significantly increased in TAC compared to WT after 24 h. In mice with BNP infusion, MCIP was significantly lower 6 h after TAC compared to control animals. In conclusion, mechanical load leads to an upregulation of SERCA expression. This is followed by upregulation of natriuretic peptides with subsequent suppression of SERCA upregulation. Elevated natriuretic peptides may suppress SERCA expression by inhibition of calcineurin activity via activation of GC-A.

Topics: Animals; Atrial Natriuretic Factor; Calcineurin; Cyclic GMP; Disease Models, Animal; Female; Guanylate Cyclase; Heart Failure; LIM Domain Proteins; Mice; Mice, Knockout; Mice, Transgenic; Muscle Proteins; Myocardial Contraction; Natriuretic Peptide, Brain; NFATC Transcription Factors; Receptors, Atrial Natriuretic Factor; RNA, Messenger; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Time Factors; Up-Regulation

Persistent pulmonary hypertension of the newborn (PPHN) is a major clinical problem. Nitric oxide produced by endothelial nitric oxide synthase (eNOS) in endothelial cells plays an important role in the pathogenesis of PPHN. The eNOS expression in endothelial cells is controlled by epigenetic regulation. The aim of this study was to investigate the epigenetic regulatory mechanisms of the eNOS gene in PPHN.. The rat model of PPHN was induced by hypoxia and indomethacin. Pulmonary vascular endothelial cells were isolated from the fetal rat lungs by magnetic-activated cell sorting. Chromatin immunoprecipitation and bisulfite sequencing methods were used to analyze epigenetic regulation.. The levels of acetylated histone H3 and acetylated histone H4 at the proximal promoter of the eNOS gene in pulmonary vascular endothelial cells from PPHN were significantly higher than those from the control group (P < 0.01, respectively). Total methylation percentage of the eNOS gene promoter in PPHN rat was slightly lower than that of control, but there was no statistically significant difference between the two groups (24.7 ± 2.0 vs. 27.3 ± 2.3%, P = 0.408). These changes of epigenetic modifications at the eNOS gene promoter were consistent with increased levels of eNOS mRNA and protein in PPHN.. The increased expression of eNOS in PPHN was associated with epigenetic regulation.

Topics: Animals; Animals, Newborn; CpG Islands; Disease Models, Animal; DNA Methylation; Endothelial Cells; Epigenesis, Genetic; Female; Hypertension, Pulmonary; Natriuretic Peptide, Brain; Nitric Oxide Synthase Type III; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; Sequence Analysis, DNA

The extracellular matrix (ECM) is a major determinant of the structural integrity and functional properties of the myocardium in common pathological conditions, and changes in vasculature contribute to cardiac dysfunction. Collagen (Col) XV is preferentially expressed in the ECM of cardiac muscle and microvessels.. We aimed to characterize the ECM, cardiovascular function and responses to elevated cardiovascular load in mice lacking Col XV (Col15a1(-/-)) to define its functional role in the vasculature and in age- and hypertension-associated myocardial remodeling.. Cardiac structure and vasculature were analyzed by light and electron microscopy. Cardiac function, intraarterial blood pressure, microhemodynamics, and gene expression profiles were studied using echocardiography, telemetry, intravital microscopy, and PCR, respectively. Experimental hypertension was induced with angiotensin II or with a nitric oxide synthesis inhibitor. Under basal conditions, lack of Col XV resulted in increased permeability and impaired microvascular hemodynamics, distinct early-onset and age-dependent defects in heart structure and function, a poorly organized fibrillar collagen matrix with marked interstitial deposition of nonfibrillar protein aggregates, increased tissue stiffness, and irregularly organized cardiomyocytes. In response to experimental hypertension, Col15a1 gene expression was increased in the left ventricle of wild-type mice, and mRNA expression of natriuretic peptides (ANP and BNP) and ECM modeling were abnormal in Col15a1(-/-) mice.. Col XV is necessary for ECM organization in the heart, and for the structure and functions of microvessels. Col XV deficiency leads to a complex cardiac phenotype and predisposes the subject to pathological responses under cardiac stress.

Topics: Age Factors; Aging; Angiotensin II; Animals; Atrial Natriuretic Factor; Cardiomyopathies; Collagen; Coronary Circulation; Disease Models, Animal; Echocardiography; Elasticity; Enzyme Inhibitors; Extracellular Matrix; Female; Gene Expression Profiling; Gene Expression Regulation; Genotype; Heart Ventricles; Hemodynamics; Hypertension; Male; Mice; Mice, 129 Strain; Mice, Inbred C57BL; Mice, Knockout; Microcirculation; Microscopy, Electron; Microscopy, Video; Myocardium; Natriuretic Peptide, Brain; NG-Nitroarginine Methyl Ester; Nitric Oxide Synthase; Phenotype; Polymerase Chain Reaction; RNA, Messenger; Telemetry; Ventricular Remodeling

Acute kidney injury (AKI) occurs in 30% of patients undergoing complex cardiovascular surgery, and renal ischemia-reperfusion (I/R) injury is often a contributing factor. A recent meta-analysis observed that perioperative natriuretic peptide administration was associated with a reduction in AKI requiring dialysis in cardiovascular surgery patients. This study was designed to further clarify the potential reno-protective effect of brain natriuretic peptide (BNP) using an established rat model of renal I/R injury.. The study comprised three groups (n = 10 kidneys each): (1) control (no injury); (2) I/R injury (45 min of bilateral renal ischemia followed by 3 h of reperfusion); and (3) BNP (I/R injury plus rat-BNP pretreatment at 0.01 μg/kg/min). Glomerular filtration rate (GFR) and a biomarker of AKI, urinary neutrophil gelatinase-associated lipocalin (uNGAL), were measured at baseline and at 30 minute intervals post-ischemia. Groups were compared using two-way repeated measures analysis of variance (mean ± SD, significance P < 0.05).. Baseline GFR measurements for control, I/R, and BNP groups were 1.07 ± 0.55, 0.88 ± 0.51, and 1.03 ± 0.59 mL/min (P = 0.90), respectively. Post-ischemia, GFR was significantly lower in I/R and BNP compared with controls at 30 min, 1.29 ± 0.97, 0.08 ± 0.04, and 0.06 ± 0.05 mL/min (P < 0.01), and remained lower through 3 h, 1.79 ± 0.44, 0.30 ± 0.17, and 0.32 ± 0.12 mL/min (P < 0.01). Comparing I/R to BNP groups, GFR did not differ significantly at any time point. There was no significant difference in uNGAL levels at 1 h (552 ± 358 versus 516 ± 259 ng/mL, P = 0.87) or 2 h (1073 ± 589 versus 989 ± 218 ng/mL, P = 0.79) between I/R and BNP.. BNP does not reduce the renal injury biomarker, urinary NGAL, or preserve GFR in acute renal ischemia-reperfusion injury.

Topics: Acute Disease; Acute-Phase Proteins; Animals; Biomarkers; Disease Models, Animal; Glomerular Filtration Rate; Kidney; Lipocalin-2; Lipocalins; Male; Natriuretic Peptide, Brain; Peroxidase; Proto-Oncogene Proteins; Rats; Rats, Sprague-Dawley; Reperfusion Injury

Pathological cardiac hypertrophy, induced by various etiologies such as high blood pressure and aortic stenosis, develops in response to increased afterload and represents a common intermediary in the development of heart failure. Understandably then, the reversal of pathological cardiac hypertrophy is associated with a significant reduction in cardiovascular event risk and represents an important, yet underdeveloped, target of therapeutic research. Recently, we determined that muscle ring finger-1 (MuRF1), a muscle-specific protein, inhibits the development of experimentally induced pathological; cardiac hypertrophy. We now demonstrate that therapeutic cardiac atrophy induced in patients after left ventricular assist device placement is associated with an increase in cardiac MuRF1 expression. This prompted us to investigate the role of MuRF1 in two independent mouse models of cardiac atrophy: 1) cardiac hypertrophy regression after reversal of transaortic constriction (TAC) reversal and 2) dexamethasone-induced atrophy. Using echocardiographic, histological, and gene expression analyses, we found that upon TAC release, cardiac mass and cardiomyocyte cross-sectional areas in MuRF1(-/-) mice decreased approximately 70% less than in wild type mice in the 4 wk after release. This was in striking contrast to wild-type mice, who returned to baseline cardiac mass and cardiomyocyte size within 4 days of TAC release. Despite these differences in atrophic remodeling, the transcriptional activation of cardiac hypertrophy measured by beta-myosin heavy chain, smooth muscle actin, and brain natriuretic peptide was attenuated similarly in both MuRF1(-/-) and wild-type hearts after TAC release. In the second model, MuRF1(-/-) mice also displayed resistance to dexamethasone-induced cardiac atrophy, as determined by echocardiographic analysis. This study demonstrates, for the first time, that MuRF1 is essential for cardiac atrophy in vivo, both in the setting of therapeutic regression of cardiac hypertrophy and dexamethasone-induced atrophy.

Topics: Actins; Animals; Atrophy; Dexamethasone; Disease Models, Animal; Heart Diseases; Heart-Assist Devices; Mice; Mice, Knockout; Muscle Proteins; Myocardium; Myocytes, Cardiac; Natriuretic Peptide, Brain; Tripartite Motif Proteins; Ubiquitin-Protein Ligases; Vasoconstriction; Ventricular Myosins

Mechanical unloading with a left ventricular assist device promotes "reverse remodeling," including restoration of beta-adrenergic receptor signaling and function. We compared the effects of partial unloading and complete unloading on beta-adrenergic responsiveness and gene expressions in failing rat hearts by use of heterotopic heart-lung or heart transplantation models.. Four weeks after ligation of the left anterior descending artery in Lewis rats, rats with heart failure were divided into 3 groups: infarcted hearts and lungs transplanted into the recipient rats (heart failure-partial unloading, n = 8); infarcted hearts transplanted into the recipient rats (heart failure-complete unloading, n = 7); infarcted (heart failure, n = 8) hearts without transplantation. Normal rats (n = 7) were used as controls. Papillary muscle function and gene expressions were studied at 2 or 4 weeks after transplantation.. In 2-week models, baseline developed tension of papillary muscles significantly increased in heart failure-partial unloading and heart failure-complete unloading compared with heart failure (0.15 +/- 0.07 and 0.12 +/- 0.05 g/mm(2) vs 0.02 +/- 0.01 g/mm(2), P < .05). However, in 4-week models, they decreased to 0.11 +/- 0.03 and 0.10 +/- 0.03 g/mm(2). In 4-week but not in 2-week models, the increase from baseline in baseline developed tension produced by beta-adrenergic stimulation (isoproterenol, 10(-8) and 10(-7) mol/L) was significantly increased in heart failure-partial unloading compared with heart failure-complete unloading and heart failure (P < .05). The mRNA expressions of brain natriuretic peptide and beta(1)- and beta(2)-adrenergic receptors were normalized in both 2- and 4-week models of heart failure-partial unloading.. Chronic partial unloading but not complete unloading improved beta-adrenergic responsiveness and normalized brain natriuretic peptide and beta(1)- and beta(2)-adrenergic receptor mRNA expressions in the failing rat hearts.

Topics: Animals; Cardiotonic Agents; Disease Models, Animal; Gene Expression; Heart Failure; Heart Transplantation; Heart Ventricles; Heart-Lung Transplantation; In Vitro Techniques; Isoproterenol; Male; Myocardial Contraction; Myocytes, Cardiac; Natriuretic Peptide, Brain; Papillary Muscles; Rats; Rats, Inbred Lew; Receptors, Adrenergic, beta-1; Receptors, Adrenergic, beta-2; RNA, Messenger; Ventricular Function, Left; Ventricular Remodeling

1. It has been demonstrated that epigallocatechin-3-gallate (EGCG) inhibits cardiac hypertrophy through its antihypertensive and anti-oxidant effects. However, the underlying molecular mechanism is not clear. 2. In the present study, we tested the hypothesis that EGCG attenuates transaortic abdominal aortic constriction (TAC)-induced ventricular hypertrophy by regulating mitogen-activated protein kinase (MAPK) signal pathways in hypertensive rats. Four groups of rats were used: (i) a sham-operated control group; (ii) an EGCG-treated (50 mg/kg per day, i.p., for 21 days) sham-operated group; (iii) a TAC group; and (iv) an EGCG-treated TAC group. Histological analysis of whole hearts and biochemical analyses of left ventricular (LV) tissue were used to investigate the effects of EGCG. 3. The results showed that the LV myocyte diameter and the expression of atrial natriuretic peptide, brain natriuretic peptide and β-myocardial heavy chain were significantly decreased in the EGCG-treated (50 mg/kg per day, i.p.) TAC group. Levels of reactive oxygen species and malondialdehyde in the lV were significantly reduced by EGCG in the TAC group. Total superoxide dismutase, catalase and glutathione peroxidase activities were decreased in the TAC group, and this decrease was significantly restored by EGCG treatment. Phosphorylation of extracellular signal-regulated kinase 2, p38 and c-Jun N-terminal kinase 1 was significantly reversed in the LV of EGCG-treated TAC rats (40%, 53% and 52% vs TAC, respectively), accompanied by significant inhibition of nuclear factor-κB and activator protein-1. Transaortic abdominal aortic constriction significantly upregulated LV expression of matrix metalloproteinase-9 from 32 ± 6 to 100 ± 12% and this increase was inhibited by EGCG treatment (from 100 ± 12 to 50 ± 15%). In addition, TAC decreased mitochondrial DNA copy number and the activity of respiratory chain complexes I (from 100 ± 7 to 68 ± 5%), III (from 100 ± 4 to 2 ± 5%) and IV (from 766 ± 2 to 100 ± 5%); this decrease was reversed by EGCG treatment to levels seen in sham-operated rats.

Topics: Animals; Antioxidants; Atrial Natriuretic Factor; Catalase; Catechin; Disease Models, Animal; DNA, Mitochondrial; Electron Transport Chain Complex Proteins; Enzyme Activation; Glutathione Peroxidase; Hemodynamics; Hypertension; Hypertrophy, Left Ventricular; Male; Malondialdehyde; MAP Kinase Signaling System; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mitochondria, Heart; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 8; Mitogen-Activated Protein Kinases; Myocardium; Myosin Heavy Chains; Natriuretic Peptide, Brain; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Superoxide Dismutase; Transcription Factor AP-1

We investigated the effects of iptakalim, a new ATP-sensitive potassium channel (K(ATP)) opener providing endothelial protection, on the progression of cardiac hypertrophy to failure in a rat model of pressure overloading caused by abdominal aortic banding (AAB). Endothelial dysfunction is central to cardiac hypertrophy and failure induced by pressure overload. It would be useful to clarify whether iptakalim could prevent this.. The effects of pressure overload were assessed in male Sprague-Dawley rats 6 weeks after AAB using progression of cardiac hypertrophy to heart failure as the endpoint. The AAB-treated rats had significantly elevated blood pressure, systolic and diastolic cardiac dysfunction, evidence of left ventricular hypertrophy (LVH), and transition to heart failure. LVH was characterized by increases in the ratios of heart and left ventricular weights to body weight, increased myocyte cross-sectional areas, myocardial and perivascular fibrosis, and elevated cardiac hydroxyproline. These could be prevented by treatment with iptakalim at daily oral doses of 1, 3, and 9 mg/kg for 6 weeks. Progression to cardiac failure, demonstrated by increases in relative lung and right ventricular weights, cardiac function disorders and overexpression of atrial and B-type natriuretic peptide mRNA, could also be prevented. The downregulated nitric oxide signalling system was enhanced, whereas the upregulated endothelin signalling system was inhibited, resulting in normalization of the balance between these two systems.. Iptakalim protected the endothelium and prevented progression of cardiac hypertrophy to failure induced by a pressure overload.

Topics: Animals; Aorta, Abdominal; Atrial Natriuretic Factor; Blood Pressure; Cardiovascular Agents; Disease Models, Animal; Disease Progression; Dose-Response Relationship, Drug; Endothelin-1; Endothelium, Vascular; Fibrosis; Heart Failure; Heart Rate; Hydroxyproline; Hypertension; Hypertrophy, Left Ventricular; KATP Channels; Male; Myocardium; Natriuretic Peptide, Brain; Nitric Oxide; Propylamines; Rats; Rats, Sprague-Dawley; Signal Transduction; Time Factors; Ventricular Remodeling

Ventricular myocytes are known to show increased expression of the cardiac hormones atrial and brain natriuretic peptide (ANP and BNP, respectively) in response to pathological stress on the heart, but their function during the progression of nonischemic dilated cardiomyopathy remains unclear. In this study, we crossed a mouse model of dilated cardiomyopathy and sudden death, which we generated by cardioselectively overexpressing a dominant-negative form of the transcriptional repressor neuron-restrictive silencer factor (dnNRSF Tg mice), with mice lacking guanylyl cyclase-A (GC-A), a common receptor for ANP and BNP, to assess the effects of endogenously expressed natriuretic peptides during progression of the cardiomyopathy seen in dnNRSF Tg mice. We found that dnNRSF Tg;GC-A(-/-) mice were born normally, but then most died within 4 wk. The survival rates among dnNRSF Tg;GC-A(+/-) and dnNRSF Tg mice were comparable, but dnNRSF Tg;GC-A(+/-) mice showed greater systolic dysfunction and a more severe cardiomyopathic phenotype than dnNRSF Tg mice. Collectively, our findings suggest that endogenous ANP/BNP protects the heart against the death and progression of pathological remodeling in a mouse model of dilated cardiomyopathy and sudden death.

Topics: Animals; Atrial Natriuretic Factor; Cardiomyopathy, Dilated; Death, Sudden, Cardiac; Disease Models, Animal; Female; Gene Expression; Kaplan-Meier Estimate; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardium; Natriuretic Peptide, Brain; Phenotype; Receptors, Atrial Natriuretic Factor; Repressor Proteins; RNA, Messenger; Systole; Ventricular Remodeling

The purpose of this study was to test the hypothesis that local renal delivery of B-type natriuretic peptide (BNP) will overcome renal resistance to BNP without systemic hypotension.. BNP has vasodilating, natriuretic, and renin-inhibiting properties. In overt heart failure (HF), there is development of renal resistance to BNP.. We defined the cardiorenal and humoral effects of systemic (n = 6) or local renal (n = 7) administration of canine BNP (0.01 microg/kg/min) in 2 separate groups of dogs with pacing-induced subacute overt HF complicated by renal dysfunction. We used a commercially available small (3.1-F) bifurcated renal catheter (FlowMedica Inc., Fremont, California) for direct bilateral infusion of BNP into both renal arteries.. With systemic BNP at this clinically used dose (without the bolus), urine flow increased, but there was only a trend for an increase in urinary sodium excretion and glomerular filtration rate (GFR). In contrast, local renal delivery of BNP resulted in significant diuresis and natriuresis and an increase in GFR. These diuretic and natriuretic responses were greater with local renal BNP compared with systemic BNP, and were associated with increased delivery of BNP to the renal tubules as evident by a greater urinary BNP excretion resulting in a decrease in distal reabsorption of sodium. Importantly, local renal BNP did not result in a significant decrease in mean arterial pressure that was observed with systemic BNP.. We conclude that local renal BNP delivery is a novel strategy that may overcome renal assistance to BNP in overt HF by increasing local delivery of BNP to the renal tubules.

Topics: Animals; Disease Models, Animal; Dogs; Heart Failure; Hemodynamics; Kidney; Kidney Diseases; Male; Natriuretic Peptide, Brain; Renal Agents

Oxidative stress followed by abnormal signalling can play a critical role in the development of long-term, high blood pressure-induced cardiac remodelling in heart failure (HF). Since oxidative stress-induced poly(ADP-ribose)polymerase (PARP) activation and cell death have been observed in several experimental models, we investigated the possibility that inhibition of nuclear PARP improves cardiac performance and delays transition from hypertensive cardiopathy to HF in a spontaneously hypertensive rat (SHR) model of HF.. SHRs were divided into two groups: one received no treatment (SHR-C) and the other (SHR-L) received 5 mg/kg/day L-2286 (PARP-inhibitor) orally for 46 weeks. A third group was a normotensive age-matched control group (CFY) and a fourth was a normotensive age-matched group receiving L-2286 treatment 5 mg/kg/day (CFY+L). At the beginning of the study, systolic function was similar in both CFY and SHR groups. In the SHR-C group at the end of the study, eccentric hypertrophy with poor left ventricular (LV) systolic function was observed, while PARP inhibitor treatment preserved systolic LV function. Due to these favourable changes, the survival rate of SHRs was significantly improved (P < 0.01) by the administration of the PARP inhibitor (L-2286). The PARP inhibitor used did not affect the elevated blood pressure of SHR rats, but moderated the level of plasma-BNP (P < 0.01) and favourably influenced all the measured gravimetric parameters (P < 0.05) and the extent of myocardial fibrosis (P < 0.05). The inhibition of PARP increased the phosporylation of Akt-1/GSK-3beta (P < 0.01), ERK 1/2 (P < 0.01), and PKC epsilon (P < 0.01), and decreased the phosphorylation of JNK (P < 0.05), p-38 MAPK (P < 0.01), PKC pan betaII and PKC zeta/lambda (P < 0.01), and PKC alpha/betaII and delta (P < 0.05).. These data demonstrate that chronic inhibition of PARP induces long-term favourable changes in the most important signalling pathways related to oxidative stress. PARP inhibition also prevents remodelling, preserves systolic function, and delays transition of hypertensive cardiopathy to HF in SHRs.

Topics: Administration, Oral; Animals; Blood Pressure; Cardiovascular Agents; Disease Models, Animal; Disease Progression; Enzyme Inhibitors; Extracellular Signal-Regulated MAP Kinases; Fibrosis; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Heart Failure; Hypertension; Hypertrophy, Left Ventricular; Isoenzymes; JNK Mitogen-Activated Protein Kinases; Male; Myocardium; Natriuretic Peptide, Brain; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Piperidines; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Protein Kinase C; Proto-Oncogene Proteins c-akt; Quinazolines; Rats; Rats, Inbred SHR; Signal Transduction; Time Factors; Ventricular Function, Left; Ventricular Remodeling

To study the effects of total saponins of Panax ginseng combined with berberine on hemodynamics, Plasma brain natriuretic peptide and Ca2+ concentration in cardiac cells of chronic congestive heart failure rats.. Animal models of heart failure were induced by subcutaneously injecting a large dose of ISO (80 mg x kg(-1)) for 12 days Rat and then were randomly divided into four groups: model group was given distilled water by gavage; total saponins of P. ginseng combined with berberine group was treated with total saponins of P. ginseng and berberine (each 20 mg x kg(-1); once per day) taken orally; captopril group was given captopril (45 mg x kg(-1); once per day) orally; shenmai injection group was injected intraperitoneally with shenmai injection (5 mL x kg(-1), once per day). The normal control group was given distilled water by gavage. After 4 weeks of drug treatment, rat To determine the contents of hemodynamics and plasma brain natriuretic peptide were determined and rat Ca2+ concentration in cardiomyocytes was measured by flow cytometer of each group.. Compared with normal control group, in model group can decrease the contents of LVSP, +dp/dtmax, and -dp/dtmax were decreased, but increase the contents of LVEDP, plasma brain natriuretic peptide and Ca2+ concentration were increased. The difference between two groups was significant meaning (P<0.01). Compared with model group, in total saponins of P. ginseng combined with berberine group can increase the contents of LVSP, +dp/dtmax, -dp/dtmax were increased, but were increased contents of LVEDP, plasma brain natriuretic peptide and Ca2+ concentration were decreased. The difference between two groups was significant was (P<0.01, P<0.05). Moreover, Total saponins of P. ginseng combined with berberine group had an efficacy similar to that of captopril group but superior to that of shenmai injection group.. Total saponins of P. ginseng combined with berberine has a good effect on hemodynamics, plasma brain natriuretic peptide concentration and calcium overload in experimental rats with chronic congestive heart failure.

Topics: Animals; Berberine; Calcium; Disease Models, Animal; Heart Failure; Hemodynamics; Male; Natriuretic Peptide, Brain; Panax; Rats; Rats, Wistar; Saponins

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

B-type natriuretic peptide (BNP) is an established first-line therapy for acute decompensated heart failure (HF), but its efficacy in preventing left ventricular (LV) remodeling after myocardial injury is unknown. The goal of this study was to evaluate the effects of BNP therapy on remodeling after ischemic injury in an awake canine model. Dogs were chronically instrumented for hemodynamics. Ischemia was created by daily coronary embolization (Embo; 3.1 x 10(4) beads/day) for 3 wk; 60 min after the first embolization, BNP (100 ng x kg(-1) x min(-1); n = 6) or saline (control; n = 6) was continuously infused via a left atrial catheter for 3 wk. Hemodynamics and echocardiography were performed in an awake state at baseline, 3 wk after Embo + BNP infusion, and 4 wk after stopping Embo + BNP infusion. End-systolic elastance (E(es)) and LV change in pressure over time (dP/dt) were preserved throughout Embo + BNP therapy versus control therapy (E(es): 3.76 +/- 1.01 vs. 1.41 +/- 0.16 mmHg/ml; LV dP/dt: 2,417 +/- 96 vs. 2,068 +/- 95 mmHg/s; both P < 0.05 vs. control). LV end-diastolic dimension was significantly smaller in BNP-treated dogs compared with control dogs (4.29 +/- 0.10 vs. 4.77 +/- 0.17 cm), and ejection fraction was maintained in treated dogs vs. control dogs (53 +/- 1% vs. 46 +/- 2%) (both P < 0.05 vs. control). Cyclooxygenase (COX)-2 expression in terminal LV tissue was significantly reduced after BNP therapy. Treatment with continuous infusion of BNP preserved LV geometry, improved systolic function, and prevented the progression of systolic HF after persistent ischemic injury.

Topics: Animals; Cyclic GMP; Cyclooxygenase 2; Disease Models, Animal; Dogs; Echocardiography; Embolism; Factor VIII; Female; Fibrosis; Heart Failure; Infusion Pumps; Macrophages; Male; Myocardial Ischemia; Myocardium; Natriuretic Agents; Natriuretic Peptide, Brain; Stroke Volume; Ventricular Pressure; Ventricular Remodeling

Our objective was to study the effect of the genetic background on the wound healing process after myocardial infarction (MI) in mice.. MI was induced in five different mouse strains (BalbC, C57Bl6, FVB, 129S6, and Swiss). At 3, 14, and 28 days after MI, cardiac dimensions were monitored by echocardiography and histology, whereas cardiac function was determined by direct intraventricular pressure measurements (dP/dt). Furthermore, matrix metalloproteinases were measured by zymography, and mRNA expression by quantitative PCR. Infarct rupture, which typically occurred at 3-6 days post-MI, was most frequent in 129S6 mice (62%), followed by C57Bl6 (36%), FVB (29%), Swiss (23%), and BalbC (5%). The high incidence of infarct rupture in 129S6 mice was associated with high systolic blood pressure and increased influx of inflammatory cells. Cardiac dilatation was most marked in Swiss mice and least prominent in 129S6 mice. The degree of dilatation was associated with a reduced ejection fraction and decreased dP/dt values at 14 and 28 days post-MI. At day 14 and 28 post-MI, secondary thinning of the infarct area was marked in BalbC, FVB, and Swiss, but absent in C57Bl6 and 129S6 mice. In the latter two groups, this was paralleled by the highest number of myofibroblasts at day 14 post-MI.. The outcome of infarct healing in mice strongly depends on genetic background. On the basis of our results, we suggest that for studies on infarct rupture, the 129S6 mouse is the background of choice, whereas BalbC and Swiss mice are the preferred models to study infarct thinning post-MI.

Topics: Animals; Antihypertensive Agents; Atrial Natriuretic Factor; Blood Pressure; Disease Models, Animal; Echocardiography; Gene Expression Regulation, Enzymologic; Heart Rupture, Post-Infarction; Inflammation; Male; Matrix Metalloproteinases; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain; Polymerase Chain Reaction; RNA, Messenger; Species Specificity; Stroke Volume; Time Factors; Ventricular Function, Left; Ventricular Pressure; Wound Healing

Left ventricular (LV) hypertrophy (LVH) is an independent risk factor for cardiovascular mortality and is commonly caused by hypertension. In rodents, transverse aortic constriction (TAC) is a model regularly employed in mechanistic studies of the response of the LV to pressure overload. We previously reported that inbred strains of male mice manifest different cardiac responses to TAC, with C57BL/6J (B6) developing LV dilatation and impaired contractility and 129S1/SvImJ (129) males displaying concentric LVH. In the present study, we investigated sex and parent-of-origin effects on the response to TAC by comparing cardiac function, organ weights, expression of cardiac hypertrophy markers, and histology in female B6 and female 129 mice and in F1 progeny of reciprocal crosses between B6 and 129 mice (B6129F1 and 129B6F1). Five weeks after TAC, heart weight increased to the greatest extent in 129B6F1 mice and the least extent in 129 and B6129F1 mice. Female 129B6F1 and B6 mice were relatively protected from the increase in heart weight that occurs in their male counterparts with pressure overload. The response to TAC in 129 consomic mice bearing the B6 Y chromosome resembled that of 129 rather than 129B6F1 mice, indicating that the B6 Y chromosome does not account for the differences in the reciprocal cross. Our results suggest that susceptibility to LVH is more complex than simple Mendelian inheritance and that parental origin effects strongly impact the LV response to TAC in these commonly used inbred strains.

Topics: Animals; Aortic Diseases; Atrial Natriuretic Factor; Blood Pressure; Body Weight; Disease Models, Animal; Epigenesis, Genetic; Female; Fibrosis; Genes, Y-Linked; Hypertrophy, Left Ventricular; Male; Mice; Mice, Inbred C57BL; Myosin Heavy Chains; Natriuretic Peptide, Brain; Organ Size; Sex Factors; Species Specificity

Topics: Animals; Cardiomyopathy, Dilated; Disease Models, Animal; Echocardiography; Echocardiography, Doppler, Color; Echocardiography, Transesophageal; Heart Failure; Heart Valve Prosthesis; Heart-Assist Devices; Humans; Mitral Valve; Mitral Valve Insufficiency; Natriuretic Peptide, Brain; Peptide Fragments; Polyesters; Randomized Controlled Trials as Topic; Surgical Mesh; Ventricular Dysfunction, Left

Diabetic cardiomyopathy is an important contributor to diastolic and systolic heart failure. We examined the nature and mechanism of the cardiomyopathy in Akita (Ins2(WT/C96Y)) mice, a model of genetic nonobese type 1 diabetes that recapitulates human type 1 diabetes. Cardiac function was evaluated in male Ins2WT/C96Y and their littermate control (Ins2WT/WT) mice using echocardiography and tissue Doppler imaging, in vivo hemodynamic measurements, as well as ex vivo working heart preparation. At 3 and 6 mo of age, Ins2WT/C96Y mice exhibited preserved cardiac systolic function compared with Ins2WT/WT mice, as evaluated by ejection fraction, fractional shortening, left ventricular (LV) end-systolic pressure and maximum rate of increase in LV pressure in vivo, cardiac work, cardiac power, and rate-pressure product ex vivo. Despite the unaltered systolic function, Ins2WT/C96Y mice exhibited significant and progressive diastolic dysfunction at 3 and 6 mo of age compared with Ins2WT/WT mice as assessed by tissue and pulse Doppler imaging (E-wave velocity, isovolumetric relaxation time) and by in vivo hemodynamic measurements (LV end-diastolic pressure, time constant of LV relaxation, and maximum rate of decrease in LV pressure). We found no evidence of myocardial hypertrophy or fibrosis in the Ins2WT/C96Y myocardium. Consistent with the lack of fibrosis, expression of procollagen-alpha type I, procollagen-alpha type III, and fibronectin were not increased in these hearts. Ins2WT/C96Y hearts showed significantly reduced sarcoplasmic reticulum Ca2+-ATPase 2a (cardiac sarcoplasmic reticulum Ca2+ pump) levels, elevated beta-myosin heavy chain isoform, increased long-chain fatty acids, and triacylglycerol with evidence of lipotoxicity, as indicated by a significant rise in ceramide, diacylglycerol, and lipid deposits in the myocardium. Consistent with metabolic perturbation, and a switch to fatty acid oxidation from glucose oxidation in Ins2WT/C96Y hearts, expression of mitochondrial long-chain acyl-CoA dehydrogenase and pyruvate dehydrogenase kinase isoform 4 were increased. Insulin treatment reversed the diastolic dysfunction, the elevated B-type natriuretic peptide and beta-myosin heavy chain, and the reduced sarcoplasmic reticulum Ca2+-ATPase 2a levels with abolition of cardiac lipotoxicity. We conclude that early type 1 diabetic cardiomyopathy is characterized by diastolic dysfunction associated with lipotoxic cardiomyopathy with preserved systolic function in t

Topics: Acyl-CoA Dehydrogenase, Long-Chain; Age Factors; Animals; Blood Glucose; Cardiomyopathies; Ceramides; Diabetes Mellitus, Type 1; Diastole; Diglycerides; Disease Models, Animal; Disease Progression; Echocardiography, Doppler, Pulsed; Fatty Acids; Hypoglycemic Agents; Insulin; Lipid Metabolism; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Mitochondria, Heart; Myocardial Contraction; Myocardium; Myosin Heavy Chains; Natriuretic Peptide, Brain; Protein Serine-Threonine Kinases; Pyruvate Dehydrogenase Acetyl-Transferring Kinase; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Stroke Volume; Systole; Triglycerides; Ventricular Dysfunction, Left; Ventricular Pressure

Hyperlipidaemia interferes with cardioprotective mechanisms, but the cause of this phenomenon is largely unknown, although hyperlipidaemia impairs the cardioprotective NO-cGMP system. However, it is not known if natriuretic peptide-cGMP-protein kinase G (PKG) signalling is affected by hyperlipidaemia. Therefore, we investigated the cardioprotective efficacy of cGMP-elevating agents in hearts from normal and hyperlipidaemic rats.. Male Wistar rats were rendered hyperlipidaemic by feeding with 2% cholesterol-enriched chow for 12 weeks. Hearts isolated from normal and hyperlipidaemic rats were perfused (Langendorff mode) and subjected to 30 min occlusion of the left main coronary artery, followed by 120 min reperfusion. 8-Br-cGMP (CG, 10 nM), B-type natriuretic peptide-32 (BNP, 10 nM), S-nitroso-N-acetyl-penicillamine (SNAP, 1 microM) were perfused from 10 min prior to coronary occlusion until the 15th min of reperfusion. Infarct size (% of ischaemic risk zone) was determined by triphenyltetrazolium staining.. Treatment with CG, SNAP or BNP decreased infarct size significantly in normal hearts from its control value of 41.6 +/- 2.9% to 15.5 +/- 2.4%, 23.3 +/- 3.0% and 25.3 +/- 4.6%, respectively (P < 0.05). Protection by BNP was abolished by co-perfusion of PKG inhibitors KT5823 (600 nM) or Rp-8pCPT-PET-cGMPs (1 microM), confirming its PKG dependence. In hearts from hyperlipidaemic rats, CG, SNAP or BNP failed to decrease infarct size. Hyperlipidaemia did not alter basal myocardial PKG content, but decreased its activity as assessed by phosphorylation of cardiac troponin I.. This is the first demonstration that defects in the cardioprotective cGMP-PKG system could be a critical biochemical anomaly in hyperlipidaemia.

Topics: Animals; Cardiotonic Agents; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Dietary Fats; Disease Models, Animal; Hyperlipidemias; Male; Myocardial Infarction; Myocardial Reperfusion Injury; Natriuretic Peptide, Brain; Phosphorylation; Rats; Rats, Wistar; S-Nitroso-N-Acetylpenicillamine; Troponin I

This study aims to determine whether a relation exists between ischemia/reperfusion and myocardial B-type natriuretic peptide (BNP) mRNA expression independent of variations in intracavitary diastolic volume and consequently, of cardiomyocyte stretching. Twenty-three rats were subjected to the following conditions: control (C), 15 min of ischemia (I15), or ischemia plus 15 (R15), 30 (R30), or 45 (R45) min of reperfusion in the in situ hearts. Isolated hearts of sixteen additional rats (sham, n = 8; occlusion, n = 8) were perfused for studies in the absence of ventricular distension. All hearts were divided in two segments (ischemic and nonischemic). Ventricular distension was avoided by excluding the atria and mitral valves. In both experiments, BNP mRNA was quantified by real-time polymerase chain reaction in both nonischemic and ischemic regions. In the in situ hearts, myocardial BNP mRNA values at R15 (4.24 +/- 0.75) in the ischemic region were higher than in other groups (C: 1.43 +/- 0.81, P = 0.044; I15: 3.05 +/- 0.62, P = 0.048; R30: 0.76 +/- 0.84, P = 0.001; R45: 1.47 +/- 0.60, P = 0.046, [analysis of variance]). In isolated hearts without ventricular distension, myocardial BNP mRNA (arbitrary units) content at R15 in ischemic regions (4.54 +/- 0.26) was greater than in nonischemic regions in both occlusion (3.51 +/- 0.20, P < 0.001) and sham (3.38 +/- 0.25, P = 0.0001 and 3.47 +/- 0.19, P = 0.0001) groups. The present data show that ischemia/reperfusion is responsible for increased BNP mRNA myocardial content independent of changes of ventricular cavity diastolic volume.

Topics: Animals; Disease Models, Animal; Female; Myocardial Ischemia; Myocardial Reperfusion; Myocardium; Natriuretic Peptide, Brain; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Time Factors; Up-Regulation

Occlusion of the left atrial appendage is proposed to reduce the risk of stroke in patients with atrial fibrillation. The third-generation atrial exclusion device, modified to provide uniform distribution of pressure at appendage exclusion, was assessed for safety and effectiveness in a canine model and compared with a surgical stapler.. The atrial exclusion device consists of 2 parallel, straight, rigid titanium tubes and 2 nitinol springs with a knit-braided polyester fabric. Fourteen mongrel dogs were implanted with the device at the base of the left atrial appendage via a median sternotomy. In each dog, the right atrial appendage was stapled with a commercial apparatus for comparison. The animals were evaluated at 7 days (n = 3), 30 days (n = 5), and 90 days (n = 6) after implantation by epicardial echocardiography, left atrial and coronary angiography, gross pathology, and histology.. Left atrial appendage exclusion was complete and achieved without hemodynamic instability, and coronary angiography revealed that the left circumflex artery was patent in all cases. A new endothelial tissue layer developed on the occluded orifice of the left atrium 90 days after implantation. This endothelial layer was not evident on the stapled right atrial appendage.. In dogs, the third-generation atrial exclusion device achieved easy, reliable, and safe exclusion of the left atrial appendage with favorable histologic results. Clinical application could provide a new therapeutic option for reducing the risk of stroke in patients with atrial fibrillation.

Topics: Analysis of Variance; Angiography; Animals; Atrial Appendage; Atrial Fibrillation; Disease Models, Animal; Dogs; Echocardiography, Doppler; Hemodynamics; Immunohistochemistry; Natriuretic Peptide, Brain; Probability; Prostheses and Implants; Prosthesis Design; Prosthesis Implantation; Random Allocation; Sensitivity and Specificity; Stroke; Surgical Instruments

To assess the effects of rhBNP on left ventricular (LV) remodeling in rats with acute myocardial infarction (AMI).. AMI was induced by ligating coronary artery in male Sprague Dawley rats. Two days after surgery, AMI rats received intravenous infusion of rhBNP (15 microg/kg or 5 microg/kg once daily, n = 15 each) or saline (placebo control, n = 15) through Jugular Vein. Sham-operated rats (n = 15) served as normal control. Four weeks later, hemodynamic measurements were performed, left ventricular weight (LVW), ratio of left ventricular weight to body weight (LVW/BW), left ventricular diameter (LVD) and infarct size were determined. Plasma angiotensin II and myocardial angiotensin II levels were also measured.. Compared with sham-operated rats, LVW, LVW/BW, LVD and myocardial angiotensin II level were significantly increased, while the LV systolic pressure (LVSP), +/- dp/dt were significantly reduced in saline treated AMI rats (all P < 0.05). LVW/BW, MI size, LVD and myocardial angiotensin II in rhBNP treated AMI rats were significantly lower [LVW: (492.6 +/- 34.0) mg, (498.8 +/- 47.8) mg, (570.0 +/- 24.2) mg, P < 0.01; LVW/BW: 2.0 +/- 0.2, 2.0 +/- 0.2, 2.3 +/- 0.1, P < 0.01; LVD: (25.3 +/- 2.9)%, (31.4 +/- 3.0)%, (46.4 +/- 3.0)%, P < 0.01; myocardial angiotensin II: (881.3 +/- 62.7) pg/L, (1186.0 +/- 94.5) pg/L, (2436.7 +/- 280.3) pg/L, P < 0.05], while LVSP and +/- dp/dt in rhBNP treatment groups were significantly increased than saline treated AMI rats (P < 0.05 or P < 0.01).. RhBNP is effective in attenuating left ventricular remodeling after AMI in rats.

Topics: Animals; Disease Models, Animal; Male; Myocardial Infarction; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Ventricular Remodeling

We investigated the effects of partial left ventricular unloading on failing rat hearts by using heterotopic heart-lung transplantation model. Heart failure (HF) was induced in Lewis rats by ligating the left anterior descending artery. After four weeks, the infarcted hearts and lungs were harvested and transplanted into the recipient rats by anastomosing donor's ascending aorta to recipient's abdominal aorta. Therefore, coronary venous blood entered the left ventricle (LV) and LV was partially unloaded (HF-PU group). Normal and infarcted heart rats (HF group) without transplantation served as control animals. After two weeks' unloading, the infarcted LV in HF-PU group significantly decreased its weight and myocardial diameter compared with HF group and they were close to normal levels. Developed tension of posterior papillary muscle was significantly increased in HF-PU group compared with HF group. The mRNA expressions of brain natriuretic peptide (BNP), sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2a), beta(1) and beta(2)-adrenergic receptors (beta(1) and beta(2)-AR) in LV tissue were almost normalized in HF-PU group. Partial left ventricular unloading regressed myocardial hypertrophy, reversed contractile dysfunction and normalized the mRNA (BNP, SERCA2a, beta(1) and beta(2)-AR) expressions of failing rat hearts.

Topics: Animals; Disease Models, Animal; Gene Expression; Heart Failure; Heart Transplantation; Heart Ventricles; Myocardial Contraction; Natriuretic Peptide, Brain; Polymerase Chain Reaction; Rats; Rats, Inbred Lew; Receptors, Adrenergic, beta-1; Receptors, Adrenergic, beta-2; RNA, Messenger; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Treatment Outcome; Ventricular Function, Left; Ventricular Remodeling

Brain natriuretic peptide (BNP) and N-terminal proBNP (NTproBNP) are well established in the clinic as biomarkers of heart failure. BNP hormone and the inactive NTproBNP are predominantly secreted in the ventricles of the heart in response to pressure overload and, consequently, are being investigated as markers of drug-induced cardiac hypertrophy in rat to support drug development. In the work presented here, an immunoaffinity-based LC/MS/MS assay was developed and validated to measure a selective tryptic fragment of NTproBNP in rat serum. The assay covers the range of 13-329 pg/mL of the tryptic fragment LLELIR, corresponding to 0.1-2.5 ng/mL intact NTproBNP. A stable isotope-labeled version of NTproBNP containing the tryptic fragment LLELI[13C615N1]R was prepared by solid-phase peptide synthesis and was used as an internal standard to minimize assay variability. Due to endogenous NTproBNP present in rat serum, human serum was used as the control matrix, and parallelism between rat and human serum was established by standard addition. Assay accuracy (% RE) and precision (% CV) were measured at three concentrations on each of 4 days and did not exceed 4.2 and 14.5%, respectively. Additionally, study data are presented from the application of this assay in which rats demonstrated a significant increase in NTproBNP serum concentration following administration of an agent known to induce cardiac hypertrophy. In this study, the relationship between serum NTproBNP and cardiac hypertrophy was corroborated by increases in heart weight and magnetic resonance imaging of the test subjects' left ventricle. To our knowledge, this represents the first reported assay for NTproBNP in preclinical species for the assessment of cardiac hypertrophy.

Topics: Amino Acid Sequence; Animals; Biomarkers; Cardiomyopathy, Hypertrophic; Chromatography, Liquid; Disease Models, Animal; Humans; Immunoprecipitation; Mass Spectrometry; Molecular Sequence Data; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley; Time Factors

Circulating levels of atrial natriuretic peptide and brain natriuretic peptide (BNP) are elevated in patients with cyanotic congenital heart disease and associated with the severity of ventricular dysfunction. We evaluated the effect of chronic hypoxemia on left ventricle pro-atrial natriuretic peptide and pro-BNP, the cytoplasmic precursors of the plasma hormones.. Forty newborn piglets were randomized to placement of a pulmonary artery to left atrium shunt to create hypoxemia or sham thoracotomy. Animals were studied at 1 or 2 weeks after the procedure (four groups, n = 10 per group). Arterial oxygen tension and hematocrit were obtained. Left ventricular shortening fraction was measured by echocardiography. Left ventricular tissue was harvested and cytoplasm was extracted. Pro-BNP levels were determined by Western blot analysis. Pro-atrial natriuretic peptide levels were determined using enzyme-linked immunosorbent assay.. Significant differences among treatment groups were observed for arterial oxygen tension (p < 0.001) and hematocrit (p < 0.001). Pairwise comparisons indicated lower arterial oxygen tension and higher hematocrit for hypoxemic piglets compared with control piglets at 1 and 2 weeks. Left ventricular shortening fraction was not decreased in the hypoxemic animals at any time (p = 0.638). Left ventricular pro-atrial natriuretic peptide decreased in hypoxemic piglets (p = 0.029), whereas left ventricular pro-BNP increased in hypoxemic piglets at 2 weeks (p = 0.002).. Chronic hypoxemia alone, even in the absence of cardiac dysfunction, is sufficient to increase ventricular levels of pro-BNP. This finding may have implications for the interpretation of BNP levels in the clinical management of patients with cyanotic congenital heart disease.

Topics: Animals; Animals, Newborn; Atrial Natriuretic Factor; Biomarkers; Chronic Disease; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Heart Defects, Congenital; Hypoxia; Natriuretic Peptide, Brain; Probability; Prognosis; Protein Precursors; Random Allocation; Sensitivity and Specificity; Swine

The cardiac natriuretic peptides atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP) are discoordinately regulated in myocardial inflammation associated with acute allograft rejection in humans and during in vitro exposure of cardiocyte cultures to some proinflammatory cytokines. We used experimental autoimmune myocarditis (EAM) to determine whether the discoordinate regulation of ANF and BNP was specific to the situations above or was generally associated with other types of myocardial inflammation. The dependency of this process to angiotensin signaling was also determined, given that previous work demonstrated beneficial effects of the angiotensin receptor blocker olmesartan in myocarditis. Histopathological changes, plasma and cardiac ANF, BNP, and selected cytokines gene expression as well as plasma cytokine levels using a cytokine array were determined in EAM, angiotensin receptor blocker-treated, and control rats. It was found that EAM specifically increases BNP but not ANF circulating levels, thus mimicking the findings in acute cardiac allograft rejection and the effect of some proinflammatory cytokines on cardiocyte cultures in vitro. Plasma cytokine array and real-time PCR revealed that lipopolysaccharide-induced CXC chemokine, monocyte chemotactic protein-1, and tissue inhibitor of metalloproteinase-1 were increased in plasma and in the myocardium of EAM rats. Olmesartan treatment reversed virtually all neuroendocrine and histopathological cardiac changes induced by EAM, thus providing a mechanistic insight into this phenomenon. It is concluded that the inflammatory process contributes specific cytokines, leading to the disregulation of cardiac ANF and BNP production observed during myocardial inflammation, and that this process is angiotensin receptor 1 dependent.

Topics: Angiotensin II Type 1 Receptor Blockers; Animals; Atrial Natriuretic Factor; Blood Pressure; Cytokines; Disease Models, Animal; Imidazoles; Mycobacterium tuberculosis; Myocarditis; Myocardium; Natriuretic Peptide, Brain; Polymerase Chain Reaction; Protein Array Analysis; Rats; Rats, Inbred Lew; Receptor, Angiotensin, Type 1; RNA, Messenger; Tetrazoles; Up-Regulation

Tetracycline is a powerful tool for controlling the expression of specific transgenes (TGs) in various tissues, including heart. In these mouse systems, TG expression is repressed/enhanced by adding doxycycline (Dox) to the diet. However, Dox has been shown to attenuate matrix metalloproteinase (MMP) expression and activity in various tissues, and MMP inactivation mitigates left ventricular (LV) remodeling in animal models of heart failure. Therefore, we examined the influence of Dox on LV remodeling and MMP expression in mice after transverse aortic constriction (TAC). One month after TAC, cardiac hypertrophy (99% vs. 67%) and the proportion of mice exhibiting congestive heart failure (CHF, 74% vs. 32%) were higher in the TAC + Dox group than in the TAC group (P < 0.05). These differences were no longer seen 2 mo after TAC, although LV was more severely dilated in TAC + Dox mice than in TAC mice (P < 0.05). One month after TAC, the increase in brain natriuretic peptide and beta-myosin heavy chain mRNA levels was 1.6 and 1.7 times higher, respectively, in TAC + Dox mice than in TAC mice (P < 0.01). MMP-2 gelatin zymographic activity increased 1.9- and 2.4-fold in TAC and TAC + Dox mice, respectively (P < 0.01 and P < 0.05 relative to respective sham-operated animals), but the difference between TAC + Dox and TAC mice did not reach statistical significance. Dox did not significantly alter TAC-associated perivascular and interstitial myocardial fibrosis. These findings demonstrate that Dox accelerates the onset of cardiac hypertrophy and the progression to CHF following TAC in mice. Accordingly, care should be taken when designing and interpreting studies based on TG mouse models of LV hypertrophy using the tetracycline-regulated (tet)-on/tet-off system.

Topics: Animals; Aorta, Thoracic; Calcium-Binding Proteins; Constriction; Disease Models, Animal; Disease Progression; Doxycycline; Fibrosis; Heart Failure; Hemodynamics; Hypertrophy, Left Ventricular; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Mice; Myocardium; Myosin Heavy Chains; Natriuretic Peptide, Brain; Polymerase Chain Reaction; Protease Inhibitors; Ryanodine Receptor Calcium Release Channel; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Time Factors; Ultrasonography; Ventricular Remodeling

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

Left ventricular (LV) remodeling, including cardiomyocyte necrosis, scar formation, LV geometric changes, and cardiomyocyte hypertrophy, contributes to cardiac dysfunction and mortality after myocardial infarction (MI). Although precise cellular signaling mechanisms for LV remodeling are not fully elucidated, G(q) protein-coupled receptor signaling pathway, including diacylglycerol (DAG) and PKC, are involved in this process. DAG kinase (DGK) phosphorylates DAG and controls cellular DAG levels, thus acting as a negative regulator of PKC and subsequent cellular signaling. We previously reported that DGK inhibited angiotensin II and phenylephrine-induced activation of the DAG-PKC signaling and subsequent cardiac hypertrophy. The purpose of this study was to examine whether DGK modifies LV remodeling after MI. Left anterior descending coronary artery was ligated in transgenic mice with cardiac-specific overexpression of DGKzeta (DGKzeta-TG) and wild-type (WT) mice. LV chamber dilatation (4.12 +/- 0.10 vs. 4.53 +/- 0.32 mm, P < 0.01), reduction of LV systolic function (34.8 +/- 8.3% vs. 28.3 +/- 4.8%, P < 0.01), and increases in LV weight (95 +/- 3.6 vs. 111 +/- 4.1 mg, P < 0.05) and lung weight (160 +/- 15 vs. 221 +/- 25 mg, P < 0.05) at 4 wk after MI were attenuated in DGKzeta-TG mice compared with WT mice. In the noninfarct area, fibrosis fraction (0.51 +/- 0.04, P < 0.01) and upregulation of profibrotic genes, such as transforming growth factor-beta1 (P < 0.01), collagen type I (P < 0.05), and collagen type III (P < 0.01), were blocked in DGKzeta-TG mice. The survival rate at 4 wk after MI was higher in DGKzeta-TG mice than in WT mice (61% vs. 37%, P < 0.01). In conclusion, these results demonstrate the first evidence that DGKzeta suppresses LV structural remodeling and fibrosis and improves survival after MI. DGKzeta may be a potential novel therapeutic target to prevent LV remodeling after MI.

Topics: Animals; Atrial Natriuretic Factor; Collagen; Diacylglycerol Kinase; Disease Models, Animal; Down-Regulation; Fibrosis; Heart Ventricles; Isoenzymes; Mice; Mice, Transgenic; Myocardial Infarction; Myocardium; Myosin Heavy Chains; Natriuretic Peptide, Brain; Protein Kinase C; Protein Transport; RNA, Messenger; Time Factors; Transforming Growth Factor beta1; Up-Regulation; Ventricular Function, Left; Ventricular Remodeling

In this work we aimed to observe (1) the changes in adrenomedullin (AM) and its receptor system - calcitonin receptor-like receptor (CRLR) and receptor activity modifying proteins (RAMPs) - in myocardial ischemic injury and (2) the response of injuried myocardia to AM and the phosphorylation of Akt to illustrate the protective mechanism of AM in ischemic myocardia. Male SD rats were subcutaneously injected with isoproterenol (ISO) to induce myocardial ischemia. The mRNA levels of AM, CRLR, RAMP1, RAMP2 and RAMP3 were determined by RT-PCR. Protein levels of Akt, phosphor-Akt, CRLR, RAMP1, RAMP2 and RAMP3 were assayed by Western blot. Results showed that, compared with that of the controls, ISO-treated rats showed lower cardiac function and myocardial injury. The mRNA relative amount of AM, CRLR, RAMP1, RAMP2 and RAMP3 in the myocardia of ISO-treated rats was increased. The elevated mRNA levels of CRLR, RAMP1, RAMP2 and RAMP3 were positively correlated with AM content in injured myocardia. The protein levels of CRLR, RAMP1, RAMP2 and RAMP3 in injured myocardia were increased compared with that of control myocardia. AM-stimulated cAMP generation in myocardia was elevated in the ISO group, and was antagonized by AM(22-52) and CGRP(8-37). Western blot analyses revealed that AM significantly enhanced Akt phosphorylation in injured myocardia, which was blocked by pretreatment with AM(22-52) or CGRP(8-37). Ischemia-injured myocardia hyper-expressed AM and its receptors - CRLR, RAMP1, RAMP2 and RAMP3 - and the response of ischemic myocardia to AM was potentiated, and the level of Akt phosphorylation was also increased, which suggests that changes in cardiac AM/AM receptor might play an important role in the pathogenesis of myocardial ischemic injury.

Topics: Adrenomedullin; Animals; Blotting, Western; Calcitonin Receptor-Like Protein; Cardiotonic Agents; Cyclic AMP; Disease Models, Animal; Gene Expression Regulation; Heart; Intracellular Signaling Peptides and Proteins; Isoproterenol; Lipid Peroxides; Male; Membrane Proteins; Myocardial Ischemia; Myocardium; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Phosphorylation; Proto-Oncogene Proteins c-akt; Radioimmunoassay; Rats; Rats, Sprague-Dawley; Receptor Activity-Modifying Proteins; Receptors, Calcitonin; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

The aim of this work was to test whether acute phosphodiesterase 5 (PDE5) inhibition via sildenafil (SIL) mimics and/or potentiates cardiorenal effects of exogenous natriuretic peptide (NP) infusion.. Heart failure (HF) is often accompanied by elevated NP secretion yet blunted responsiveness. Such NP resistance may, in part, relate to increased cyclic guanosine monophosphate (cGMP) catabolism by PDE5.. Dogs (n = 7) were studied before and after tachypacing-induced HF. Animals received 30-min infusion of B-type natriuretic peptide (BNP) (2 mug/kg bolus, 0.02 mug/kg/min), and on a separate day SIL (1 mg/kg, intravenous), followed by BNP (SIL + BNP). Phosphodiesterase 5 activity was measured in lung, vasculature, and kidney.. At baseline (non-failing), BNP lowered central venous, pulmonary capillary wedge, diastolic, mean pulmonary artery, and mean arterial pressure. Sildenafil had no effects, and SIL + BNP was similar to BNP alone. In contrast, SIL lowered these pressures similarly to BNP in dogs with HF, and SIL + BNP was additive in further reducing pulmonary pressures over BNP alone. Plasma cGMP/plasma BNP ratio was markedly reduced with HF, indicating NP resistance. Sildenafil plus BNP increased this ratio in HF, but had no effect in non-failing animals. Sildenafil had no independent diuretic/natriuretic effects nor did it enhance BNP effects under baseline or HF conditions. In HF, PDE5 activity was significantly increased in the systemic and pulmonary vasculature and in the kidney.. The PDE5 activity in systemic and pulmonary vasculature increases in HF rendering hemodynamic responses to PDE5 inhibition identical to those from BNP infusion. Natriuretic peptide desensitization in HF relates, in part, to increased PDE5 activity, supporting a therapeutic role for PDE5 inhibition.

Topics: 3',5'-Cyclic-GMP Phosphodiesterases; Animals; Cyclic Nucleotide Phosphodiesterases, Type 5; Disease Models, Animal; Dogs; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Synergism; Female; Heart Failure; Infusions, Intravenous; Male; Multivariate Analysis; Natriuretic Peptide, Brain; Piperazines; Probability; Purines; Random Allocation; Reference Values; Risk Factors; Sensitivity and Specificity; Sildenafil Citrate; Sulfones

Topics: Animals; Biomarkers; Cardiac Output; Disease Models, Animal; Dogs; Heart Failure; Humans; Natriuretic Peptide, Brain; Phosphodiesterase Inhibitors; Reference Values; Risk Assessment; Sensitivity and Specificity

Mutations in striated muscle alpha-tropomyosin (alpha-TM), an essential thin filament protein, cause both dilated cardiomyopathy (DCM) and familial hypertrophic cardiomyopathy. Two distinct point mutations within alpha-tropomyosin are associated with the development of DCM in humans: Glu40Lys and Glu54Lys. To investigate the functional consequences of alpha-TM mutations associated with DCM, we generated transgenic mice that express mutant alpha-TM (Glu54Lys) in the adult heart. Results showed that an increase in transgenic protein expression led to a reciprocal decrease in endogenous alpha-TM levels, with total myofilament TM protein levels remaining unaltered. Histological and morphological analyses revealed development of DCM with progression to heart failure and frequently death by 6 months. Echocardiographic analyses confirmed the dilated phenotype of the heart with a significant decrease in the left ventricular fractional shortening. Work-performing heart analyses showed significantly impaired systolic, and diastolic functions and the force measurements of cardiac myofibers revealed that the myofilaments had significantly decreased Ca(2+) sensitivity and tension generation. Real-time RT-PCR quantification demonstrated an increased expression of beta-myosin heavy chain, brain natriuretic peptide, and skeletal actin and a decreased expression of the Ca(2+) handling proteins sarcoplasmic reticulum Ca(2+)-ATPase and ryanodine receptor. Furthermore, our study also indicates that the alpha-TM54 mutation decreases tropomyosin flexibility, which may influence actin binding and myofilament Ca(2+) sensitivity. The pathological and physiological phenotypes exhibited by these mice are consistent with those seen in human DCM and heart failure. As such, this is the first mouse model in which a mutation in a sarcomeric thin filament protein, specifically TM, leads to DCM.

Topics: Actin Cytoskeleton; Actins; Animals; Calcium; Calcium-Transporting ATPases; Cardiomyopathy, Dilated; Cardiomyopathy, Hypertrophic, Familial; Disease Models, Animal; Echocardiography; Gene Expression Regulation; Humans; Mice; Mice, Mutant Strains; Mice, Transgenic; Muscle Contraction; Muscle Fibers, Skeletal; Mutation, Missense; Natriuretic Peptide, Brain; Reverse Transcriptase Polymerase Chain Reaction; Ryanodine Receptor Calcium Release Channel; Sarcoplasmic Reticulum; Tropomyosin; Ventricular Myosins

Although a host of studies catalogue changes that occur with the development of left ventricular hypertrophy (LVH), there is little information about features related solely to LVH regression. This is due, in part, to a lack of animal models to study this question. While traditional models of aortic banding have provided useful information regarding the development of LVH, a similarly effective model is necessary to study mechanisms associated with LVH regression.. Minimally invasive transverse arch banding was performed in C57BL6 mice using a slipknot technique. Twenty-eight days later, the band was removed. Carotid Doppler velocity gradients were serially measured to assess the degree of aortic constriction. Echocardiography, histology, electron microscopy, and real-time polymerase chain reaction were used to assess functional, structural, and genetic aspects of hypertrophy.. Banding of the transverse arch created the expected increase in aortic velocity and gradient between the left and right carotid artery, which normalized with relief of the constriction. Pressure overload resulted in a robust hypertrophic response as assessed by heart weight/body weight ratios, gross and microscopic histology, transthoracic echocardiography, electron microscopy, and hypertrophy gene expression. These markers were reversed within 1 week following debanding and were maintained for up to 4 weeks. Mortality rate for the cumulative procedure was 5% over a 2-month period.. These results demonstrate a safe, effective, and reproducible method of promoting LVH regression-avoiding the need for endotracheal intubation, mechanical ventilation, and a second invasive surgery to remove the constriction. The simplicity of this technique combined with the well-known advantages of using the mouse species makes this model both unique and relevant. Ultimately, this model will facilitate focused study of independent mechanisms involved with LVH regression.

Topics: Animals; Aorta, Thoracic; Blood Flow Velocity; Carotid Arteries; Disease Models, Animal; Echocardiography; Hypertrophy, Left Ventricular; Laser-Doppler Flowmetry; Male; Mice; Mice, Inbred C57BL; Natriuretic Peptide, Brain; Organ Size; Recovery of Function; RNA, Messenger; Survival Rate

Aortic regurgitation (AR) causes left ventricular (LV) volume overload, leading to progressive LV dilatation and dysfunction. In the present study it was examined whether blockade of angiotensin II type 1 receptor (AT1) could improve survival in cases of chronic severe AR.. AR was induced by puncturing the aortic valves of wild-type (WT) and AT1a knockout (KO) mice. Mice that survived for 4 weeks after the operation were deemed to be a model of chronic severe AR and were followed up for 50 weeks (WT, n=29; KO, n=31). Baseline measurements made 4 weeks after surgery showed similar LV cavity and function in both genotypes. These conditions progressively worsened in both genotypes, but 16 weeks after baseline, KO mice showed significantly less LV dilatation, hypertrophy and interstitial fibrosis than WT mice. Cardiac mRNA expression of B-type natriuretic peptide and type I collagen was lower in KO than WT mice. The 50-week mortality rate was significantly lower among KO (45.2%) than WT (86.2%) mice, and postmortem findings indicated that the lower mortality was attributable to a lower incidence of congestive heart failure.. In cases of chronic severe AR, blockade of AT1 attenuates the progression of LV dilatation, hypertrophy and fibrosis, thereby mitigating heart failure and improving long-term survival.

Topics: Animals; Aortic Valve Insufficiency; Chronic Disease; Disease Models, Animal; Heart Failure; Mice; Mice, Knockout; Natriuretic Peptide, Brain; Receptor, Angiotensin, Type 1; RNA, Messenger; Survival Rate; Ventricular Dysfunction, Left; Ventricular Remodeling

Heat shock protein (HSP) 60 is a mitochondrial and cytosolic protein. Previously, we reported that HSP60 doubled in end-stage heart failure, even though levels of the protective HSP72 were unchanged. Furthermore, we observed that acute injury in adult cardiac myocytes resulted in movement of HSP60 to the plasma membrane. We hypothesized that the inflammatory state of heart failure would cause translocation of HSP60 to the plasma membrane and that this would provide a pathway for cardiac injury. Two models were used to test this hypothesis: 1) a rat model of heart failure and 2) human explanted failing hearts. We found that HSP60 localized to the plasma membrane and was also found in the plasma early in heart failure. Plasma membrane HSP60 localized to lipid rafts and was detectable on the cell surface with the use of both flow cytometry and confocal microscopy. Localization of HSP60 to the cell surface correlated with increased apoptosis. In heart failure, HSP60 is in the plasma membrane fraction, on the cell surface, and in the plasma. Membrane HSP60 correlated with increased apoptosis. Release of HSP60 may activate the innate immune system, promoting a proinflammatory state, including an increase in TNF-alpha. Thus abnormal trafficking of HSP60 to the cell surface may be an early trigger for myocyte loss and the progression of heart failure.

Topics: Aged; Animals; Apoptosis; Atrial Natriuretic Factor; Cardiomyopathies; Chaperonin 60; Cytosol; Disease Models, Animal; Disease Progression; Female; Heart Failure; Heart Ventricles; Humans; Male; Membrane Microdomains; Middle Aged; Mitochondria, Heart; Myocardial Contraction; Myocytes, Cardiac; Natriuretic Peptide, Brain; Protein Transport; Rats; Rats, Sprague-Dawley; Time Factors; Tumor Necrosis Factor-alpha; Up-Regulation

Natriuretic peptides are regulatory autacoids in the mammalian myocardium whose functions, mediated via particulate guanylyl cyclase/cGMP, may include cytoprotection against ischaemia-reperfusion injury. Previous work has identified that B-type natriuretic peptide (BNP) limits infarct size when administered prior to and during coronary occlusion through a K(ATP) channel-dependent mechanism. The present study examined the hypothesis that the protection afforded by BNP is mediated specifically at reperfusion in a postconditioning-like manner. Langendorff-perfused rat hearts were subjected to 35 min coronary artery occlusion and 120 min reperfusion, and infarct size was determined by tetrazolium staining. Postconditioning was effected by applying six 10-second periods of global ischaemia at the onset of reperfusion.Treatment with either BNP 10 nM or the NO donor S-nitroso-N-acetylpenicillamine (SNAP) 1-10 microM was commenced 5 min prior to reperfusion and continued until 10 min after reperfusion. Control infarct size (% of ischaemic risk zone) was 40.8 +/- 3.7%.BNP at reperfusion induced a significant limitation of infarct size (BNP 22.9 +/- 4.1% P<0.05 vs. control). Co-treatment at reperfusion with BNP and the K(ATP) channel blockers 5-hydroxydecanote (5HD, 100 microM), glibenclamide (Glib; 10 microM) or HMR1098 (10 microM) abolished the infarct-limiting effect of BNP (BNP + 5HD 41.0 +/- 3.9%, BNP + Glib 39.8 +/- 5.6%, BNP + HMR 1098 46.0 +/- 7.1%,P < 0.05 vs. BNP). BNP given together with L-NAME (100 microM) at reperfusion resulted in a marked loss of protection (BNP + L-NAME 53.1 +/- 3.8% P < 0.001 vs. BNP). In a second series of experiments, SNAP (1-10 microM) given at reperfusion was found not to be protective (SNAP 1 microM 30.2 +/- 4.9%, SNAP 2 microM 27.5 +/- 9.5%, SNAP 5 microM 39.2 +/- 5.7%, SNAP 10 microM 33.7 +/- 6.4%, not significant vs. control). In a third series of experiments, postconditioning significantly limited infarct size (14.9 +/- 3.6 % vs. control 34.5 +/- 4.9%, P < 0.01) and this effect of postconditioning was abolished in the presence of isatin (100 microM), a non-specific blocker of particulate guanylyl cyclases (35.1 +/- 6%, P < 0.05 vs. postconditioning). In conclusion, pharmacological activation of pGC by BNP can effectively induce protection against reperfusion injury, by mechanisms involving K(ATP) channel opening and endogenous NO synthase activation. Furthermore, endogenous activation of pGC could play a role in the mechan

Topics: Animals; Disease Models, Animal; KATP Channels; Male; Myocardial Contraction; Myocardial Infarction; Myocardial Reperfusion; Myocardial Reperfusion Injury; Myocardium; Natriuretic Agents; Natriuretic Peptide, Brain; Nitric Oxide; Nitric Oxide Synthase; Rats; Rats, Sprague-Dawley; Regional Blood Flow

The objective of the study was to determine alterations in cGMP, soluble guanylate cyclase (sGC), phosphodiesterase type 5 (PDE5), and B-type natriuretic peptide (BNP), in an animal model of a congenital cardiac defect with increased pulmonary blood flow.. Prospective, comparative, experimental study.. Lambs, from birth until 8 weeks of age.. Late gestation fetal lambs underwent in utero placement of an 8 mm aortopulmonary vascular graft (shunt). In shunted and normal age-matched control lambs, at 2, 4, and 8 weeks of age, cGMP and BNP levels were measured, and sGC subunit and PDE5 protein expression were determined by Western blot analysis and immunohistochemistry.. In shunted lambs, tissue and plasma cGMP levels were greater than normal throughout the 8-week study period (P < 0.05). sGCalpha protein was greater at 2 and 4 weeks (P < 0.05), and sGCbeta and PDE5 protein were greater at 4 weeks in shunted lambs (P < 0.05). Plasma BNP levels did not change in normal lambs but increased in shunted lambs by 8 weeks of age (P < 0.05). BNP levels were greater in shunted lambs than normal at 4 and 8 weeks (P < 0.05).. Alterations in sGC subunit protein expression during the first post-natal month, and increased BNP levels during the second post-natal month contribute to elevations in plasma and lung tissue cGMP in lambs with increased pulmonary blood flow.

Topics: Animals; Animals, Newborn; Animals, Suckling; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 5; Disease Models, Animal; Gene Expression Profiling; Guanylate Cyclase; Heart Defects, Congenital; Natriuretic Peptide, Brain; Pulmonary Circulation; Sheep

Activation of BNP and IL-6 are hallmarks of left ventricular (LV) dysfunction and congestive heart failure (CHF). To assess the relative activation of BNP and IL-6 in clinical and experimental heart failure, we performed a human study in which plasma N-terminal proBNP (NT-proBNP) and IL-6 were measured in a large group of patients in the chronic phase after myocardial infarction (MI) and an animal study in which LV gene expression of BNP and IL-6 was assessed in rapid ventricular pacing-induced heart failure. In the human study, NT-proBNP and IL-6 were measured by non-extracted, enzyme-linked immunoassay in 845 subjects (n=468 outpatients after MI, MONICA MI register Augsburg; and 377 siblings without MI, control). NT-proBNP (295+/-23pg/mL vs. CTRL 84+/-8, P<0.05) and IL-6 (2.7+/-0.1pg/mL vs. CTRL 2.1+/-0.1, P<0.05) were both elevated in subjects with MI. These increases were particularly pronounced in the presence of concomitant CHF (both P<0.01 vs. CTRL) and LV dysfunction (EF<45%, both P<0.05 vs. CTRL). However, NT-proBNP was significantly correlated with several cardiac structural and functional parameters (EF, LVMI, history of MI, CHF symptoms; all P<0.05) upon regression analysis whereas IL-6 was only correlated with history of MI (P<0.001). Accordingly, MI subjects with symptomatic LV dysfunction were detected by NT-proBNP with a greater sensitivity, specificity, and ROC-area (85%, 88%, and 0.87, respectively) as compared to IL-6 (69%, 53%, and 0.67, respectively). In the animal study, IL-6 and BNP expression were both significantly elevated in CHF (both P<0.05) but with a much greater absolute activation of BNP. In addition, BNP mRNA expression displayed a stronger inverse correlation with LV function (r=-0.74; P<0.001) than IL-6 (r=-0.53; P=0.001) and was a markedly more sensitive and specific molecular marker of LV dysfunction (sensitivity 91%, specificity 100%, ROC-area 0.94) than IL-6 (sensitivity 74%, specificity 83%, ROC-area 0.87). Our animal study provides evidence that IL-6 expression is activated in heart failure but to a significantly lesser degree than that of BNP. Both the stronger expression of BNP and the better correlation with LV function provide the molecular basis for a diagnostic superiority of NT-proBNP in clinical LV dysfunction and heart failure.

Topics: Animals; Biomarkers; Chronic Disease; Disease Models, Animal; Female; Follow-Up Studies; Heart Failure; Humans; Interleukin-6; Male; Middle Aged; Myocardial Infarction; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Protein Precursors; Rabbits; RNA, Messenger; Species Specificity; Ventricular Dysfunction, Left

The T-type Ca2+ channel (TCC) is activated, and abnormalities of the TCC may be related to the pathogenesis of Ca2+ overload, in cardiomyopathic hamster hearts. The aims of the present study were to investigate the alteration in expression of the TCC and to examine the effects of a dual L-and T-type Ca2+ channel blocker, efonidipine (EFO), on cardiac function and TCC during development of heart failure in UM-X7.1 cardiomyopathic hamsters.. UM-X7.1 and golden hamsters were examined, and EFO was administered at the age of 20 weeks for 4 weeks. Cardiac function was examined, the expression of TCCalpha1G was measured, and ventricular myocytes were subjected to a patch-clamp study. At 24 weeks, vehicle-treated UM-X7.1 hamsters exhibited significant increases in left ventricular (LV) size, with marked decreases in ejection fraction (LVEF) compared with golden hamsters. In the UM-X7.1 group, the expression of TCCalpha1G increased during development of heart failure compared with the golden hamster group. In the UM-X7.1 group, EFO treatment significantly attenuated the decrease of LVEF without affecting blood pressure compared with the vehicle group. EFO treatment decreased heart rate (by approximately 10%) in both groups. In the golden hamster group, EFO treatment did not affect LV function. The TCC current in ventricular myocytes was significantly increased in UM-X7.1, and was inhibited by EFO in a dose-dependent manner.. In cardiomyopathic hamster hearts, abnormalities in the TCC may be at least in part related to the pathogenesis of abnormal Ca2+ homeostasis, and TCC-blocker treatment may decrease the TCC current, resulting in an improvement of cardiac function. TCC blocker therapy might be a new strategy for certain types of heart failure.

Topics: Animals; Blood Pressure; Calcium Channel Blockers; Calcium Channels, L-Type; Calcium Channels, T-Type; Cardiomyopathies; Cricetinae; Dihydropyridines; Disease Models, Animal; Dose-Response Relationship, Drug; Electrophysiology; Female; Heart Rate; Male; Mesocricetus; Myocytes, Cardiac; Natriuretic Peptide, Brain; Nitrophenols; Organophosphorus Compounds; Patch-Clamp Techniques

The aim of the present study was to investigate how early the onset of ischaemia-induced changes in gene expression is in remote myocardium, and whether these changes would be different for left and right ventricles. Wistar rats (n=27) were randomly assigned to left coronary artery (LCA) ligation for 30 or 120 min and sham groups. Evans Blue infusion revealed antero-apical left ventricle (LV) and left intraventricular (IV) septal ischaemia (35.5+/-0.6% of LV mass). LCA ligation induced transient LV systolic dysfunction and sustained biventricular slowing of relaxation. Regarding mRNA levels, type B natriuretic peptide (BNP) was upregulated in the LV at 30 (+370+/-191%) and 120 min (+221+/-112%), whilst in the right ventricle (RV) this was only significant at 120 min (+128+/-39%). Hipoxia-inducible factor 1alpha and interleukin 6 overexpression positively correlated with BNP. Inducible NO synthase upregulation was present in both ventricles at 120 min (LV, +327+/-195%; RV, +311+/-122%), but only in the RV at 30 min (+256+/-88%). Insulin-like growth factor 1 increased in both ventricles at 30 (RV, +59+/-18%; LV, +567+/-192%) and 120 min (RV, +69+/-33%; LV, +120+/-24%). Prepro-endothelin-1 was upregulated in the RV at 120 min (+77+/-25%). Ca2+-handling proteins were selectively changed in the LV at 120 min (sarcoplasmic reticulum Ca2+ ATPase, 53+/-7%; phospholamban, +31+/-4%; Na+-Ca2+ exchanger, 31+/-6%), while Na+-H+ exchanger was altered only in the RV (-79+/-5%, 30 min; +155+/-70%, 120 min). Tumour necrosis factor-alpha and angiotensin converting enzyme were not significantly altered. A very rapid modulation of remote myocardium gene expression takes place during myocardial ischaemia, involving not only the LV but also the RV. These changes are different in the two ventricles and in the same direction as those observed in heart failure.

Topics: Animals; Coronary Vessels; Disease Models, Animal; Gene Expression Regulation; Heart Ventricles; Hypoxia-Inducible Factor 1, alpha Subunit; Ligation; Male; Myocardial Ischemia; Myocardium; Natriuretic Peptide, Brain; Nitric Oxide Synthase Type II; Rats; Rats, Wistar; RNA, Messenger; Time Factors

BNP is a cardiac peptide with vasodilating, lusitropic and natriuretic properties mediated by the second messenger cGMP. We have previously shown that chronic subcutaneous (SQ) administration of BNP in experimental CHF resulted in improved haemodynamics and unloading of the heart. However, it is unknown if this will lead to the development of tolerance to exogenous BNP.. The current study extends our previous study and compares the cardiorenal effects of acute administration of SQ BNP (5 microg/kg) in a group of dogs (n = 5) with rapid ventricular pacing induced CHF (180 bpm for 10 days) to a separate group of CHF dogs (n = 6), who received chronic SQ BNP (5 microg/kg) three times a day for 10 days.. Acute administration of SQ BNP resulted in similar increases in both plasma cGMP (35+/-5 vs. 29+/-2 pmol/ml) and urinary cGMP excretion (UcGMPV) (6000+/-1000 vs. 4000+/-600 pmol/min) in both the Chronic SQ BNP treated and the Untreated CHF groups (P > 0.05). These were associated with decreased cardiac filling pressures and increased urine flow, which were also similar in both groups.. In experimental CHF, chronic SQ BNP administration did not result in the development of tolerance as demonstrated by increases in both plasma cGMP and UcGMPV following acute administration of SQ BNP. This may have important clinical implications, suggesting that chronic BNP administration does not lead to the development of tolerance to acute BNP administration.

Topics: Animals; Cyclic GMP; Disease Models, Animal; Dogs; Drug Administration Schedule; Glomerular Filtration Rate; Heart Failure; Injections, Subcutaneous; Kidney; Male; Natriuretic Peptide, Brain; Pulmonary Wedge Pressure

We compared protective effects of a ss-adrenoceptor blocker (metoprolol; Met) and a If current (Ivabradine; Iva) in a rabbit model of myocardial infarction.. Experiments were performed on 44 adult New-Zealand-White (NZW) rabbits. The effects of either metoprolol or ivabradine were assessed 15 min after experimental occlusion of a coronary artery (CAO), 28 days after CAO (drug gavage), and in vitro hearts (Langendorff apparatus). The results were compared with sham and placebo hearts.. Metoprolol (0.25 mg/kg) slightly reduced heart rate and left ventricular systolic function. Ivabradine (0.25 mg/kg) reduced heart rate significantly (P<0.05) (18% vs control). Both drugs provided advantages over placebo: mortality was significantly (P<0.01)smaller (6/13 Pla animals died, 2/10 Met animals, and 3/11 Iva animals), left ventricular function was better preserved after 28 days (external power; Pla; Met; Iva=56%; 76%; 74%), and dilatation (BNP) was reduced (P<0.05). In the Pla group, the ST segment was significantly (P<0.05) elevated by 0.35 mV after CAO and exhibited in 50% of the animals Q waves after 28 days, while after ivabradine or metoprolol, ST displacement and Q waves had disappeared. The uneconomic myosin isoenzyme V3 predominated in Met hearts and Iva hearts (V3/V1: 63/37% and 62/38%), while it was further increased in Pla hearts (78/21%). External efficiency was lowest in Pla hearts (1.00+/-0.50 a.u.; P<0.05) and was significantly higher both in Met hearts (4.0+/-1.8 a.u.) and in Iva hearts (3.3+/-1.6 a.u.).. Met and Iva seem suited for the treatment of chronic myocardial infarction.

Topics: Adrenergic beta-Antagonists; Animals; Aorta; Benzazepines; Blood Flow Velocity; Cardiotonic Agents; Coronary Circulation; Disease Models, Animal; Electrocardiography; Heart Rate; Heart Ventricles; Ivabradine; Male; Metoprolol; Myocardial Contraction; Myocardial Infarction; Natriuretic Peptide, Brain; Oxygen Consumption; Potassium Channel Blockers; Rabbits; Time Factors; Ventricular Function, Left; Ventricular Myosins

Topics: Animals; Aortic Valve; Aortic Valve Stenosis; Calcinosis; Clinical Trials as Topic; Disease Models, Animal; Echocardiography; Female; Follow-Up Studies; Heart Valve Prosthesis; Heart Valve Prosthesis Implantation; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Natriuretic Peptide, Brain; Risk Factors; Time Factors; Tomography, X-Ray Computed

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

The goal of the study was to define the effect of chronic unloading of the normal heart on atrial endocrine function with a focus on brain natriuretic peptide (BNP), specifically addressing the role of load and neurohumoral stimulation. Although produced primarily by atrial myocardium in the normal heart, controversy persists with regard to load-dependent vs. neurohumoral mechanisms controlling atrial BNP synthesis and storage. We used a unique canine model of chronic unloading of the heart produced by thoracic inferior vena caval constriction (TIVCC), which also resulted in activation of plasma endothelin (ET-1), ANG II, and norepinephrine (NE), known activators of BNP synthesis, compared with sham. TIVCC was produced by banding of the inferior vena cava for 10 days (n = 6), whereas in control (n = 5) the band was not constricted (sham). In a third group (n = 7), the band was released on day 11, thus acutely reloading the heart. Chronic TIVCC decreased cardiac output and right atrial pressure with a decrease in atrial mass index consistent with atrial atrophy. Atrial BNP mRNA decreased compared with sham. Immunoelectron microscopy revealed an increase in BNP in atrial granules consistent with increased storage. Acute reloading increased cardiac filling pressures and resulted in an increase in plasma BNP. We conclude that chronic unloading of the normal heart results in atrial atrophic remodeling and in suppression of atrial BNP mRNA despite intense stimulation by ET, ANG II, and NE, underscoring the primacy of load in the control of atrial endocrine function and structure.

Topics: Animals; Atrial Function; Blood Pressure; Constriction; Disease Models, Animal; Dogs; Gene Expression; Heart; Male; Myocardium; Natriuretic Peptide, Brain; RNA, Messenger; Vena Cava, Inferior

Heart failure is a severe pathology, which has displayed a dramatic increase in the occurrence of patients with chronic heart disease in developed countries, as a result of increases in the population's average age and in survival time. This pathology is associated with severe malnutrition, which worsens the prognosis. Although the cachexia associated with chronic heart failure is a well-known complication, there is no reference animal model of malnutrition related to heart failure. This study was designed to evaluate the nutritional status of rats in a model of loss of cardiac function obtained by ascending aortic banding. Cardiac overload led to the development of cardiac hypertrophy, which decompensates to heart failure, with increased brain natriuretic peptide levels. The rats displayed hepatic dysfunction and an associated renal hypotrophy and renal failure, evidenced by the alteration in renal function markers such as citrullinemia, creatininemia, and uremia. Malnutrition has been evidenced by the alteration of protein and amino acid metabolism. A muscular atrophy with decreased protein content and increased amino acid concentrations in both plasma and muscle was observed. These rats with heart failure displayed a multiorgan failure and malnutrition, which reflected the clinical situation of human chronic heart failure.

Topics: Amino Acids; Animals; Aorta; Creatine Kinase; Disease Models, Animal; Heart Failure; Kidney; Ligation; Liver; Male; Malnutrition; Natriuretic Peptide, Brain; Rats; Rats, Wistar

Cerebral salt wasting (CSW) frequently occurs concomitantly with aneurysmal subarachnoid hemorrhage (SAH). CSW induces excessive natriuresis and osmotic diuresis, and reduces total blood volume. As a result, the risk of symptomatic cerebral vasospasm may be elevated. Therefore, it is important to determine the mechanism of CSW. The purpose of this study was to evaluate whether the rat SAH model exhibits CSW and to investigate the relationship between CSW and natriuretic peptides. A SAH model was produced in 24 rats by perforating a cerebral artery with a nylon thread up through the common carotid artery. To evaluate CSW, urine was cumulatively collected from SAH onset to 12 hours and sodium (Na) excretion was analyzed. Body weight and hematocrit were analyzed before and after SAH onset. Concentrations of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in plasma were also analyzed. Urine volume and total Na excretion of SAH rats were significantly higher than those of sham rats (p<0.05). Body weight of SAH rats significantly decreased and hematocrit significantly increased (p < 0.05). ANP concentration was significantly decreased in SAH rats (p<0.05). However, BNP concentrations did not change. This study demonstrated for the first time that a rat SAH model exhibited CSW. It was suggested that the cause of CSW was neither ANP nor BNP. In addition, this rat SAH model will be useful for study of CSW after SAH.

Topics: Animals; Atrial Natriuretic Factor; Carotid Artery, Common; Cerebral Arteries; Disease Models, Animal; Emaciation; Hematocrit; Male; Natriuretic Peptide, Brain; Rats; Rats, Wistar; Sodium Chloride; Subarachnoid Hemorrhage; Vasospasm, Intracranial; Wasting Syndrome

To determine the changes in plasma brain natriuretic peptide (BNP) in adriamycin-induced dilated cardiomyopathy (DCM) in rabbit, and to evaluated the significance.. Twenty-two rabbits were randomly divided into control group (n=10) and model group(n=12). The DCM model was reproduced by injecting adriamycin via ear vein for 8 weeks. Echocardiogram was performed and plasma BNP were measured before administration, and at 8 th and 11 th week after the challenge. Indexes of hemodynamics and pathological changes were observed.. Indexes of echocardiogram and hemodynamics of model group were consistent with pathologic changes of DCM. Plasma levels of BNP of the model group were increased significantly after administration of the drug(all P<0.01), though the values before the drug administration were approximately the same as in the control group. Plasma BNP levels were significantly higher in DCM group at the 11 th week than at the 8 th week (P<0.05). Plasma levels of BNP were positively correlated with and left ventricular end-diastolic volume(LVEDV), left ventricular end-systolic volume (LVESV), left ventricular end-diastolic pressure(LVEDP) and negatively correlated with left ventricular systolic pressure(LVSP), and left ventricular ejection fraction (LVEF).. Administration of intravenous adriamycin to rabbits results in DCM which in suitable for the conduction of research of neuroendocrine abnormality of heart. Overload of the left ventricle and increasing tension of left ventricular wall are key factors for regulating BNP excretion. Plasma BNP level is a good marker for evaluating degree of severity of cardiac function in DCM.

Topics: Animals; Cardiomyopathy, Dilated; Disease Models, Animal; Female; Hemodynamics; Male; Myocardium; Natriuretic Peptide, Brain; Rabbits; Random Allocation

Myosin-induced autoimmune myocarditis in rats is a model of human dilated cardiomyopathy. Rapamycin is a potent immunosuppressant and specifically inactivates the mammalian target of rapamycin (mTOR). To examine the role of mTOR in autoimmune myocarditis, we administered rapamycin to rats immunized with cardiac myosin. Phosphorylation of p70 ribosomal S6 kinase 1 (S6K1), a target of mTOR, was increased by 6.9 fold in the heart tissue of myosin immunized rats. Rapamycin (2 mg/kg/day) completely suppressed S6K1 and S6 phosphorylation. The amount of interleukin-1beta, interferon-gamma, interleukin-2, or tumor necrosis factor-alpha mRNA in the heart tissue was markedly increased in myosin-immunized rats, and rapamycin significantly attenuated the cytokine gene expressions. Rapamycin improved the survival of the rats and preserved cardiac function. The plasma level of brain natriuretic peptide increased by 4.7 fold in myosin-immunized rats, and rapamycin attenuated the increase in plasma brain natriuretic peptide. The heart weight/tibial length ratio of vehicle-treated myosin-immunized rats was increased by 1.81 +/- 0.06 fold compared with vehicle-treated unimmunized rats, and rapamycin suppressed the increase in heart weight. Rapamycin decreased the cellular infiltration and fibrosis of the myocardium. The amount of phosphorylated S6 was increased in the infiltrating mononuclear cells in vehicle-treated myosin-immunized rats. Rapamycin significantly ameliorated myocardial injury and preserved cardiac function in a rat model of autoimmune myocarditis.

Topics: Animals; Autoimmunity; Cardiomyopathy, Dilated; Disease Models, Animal; Female; Gene Expression Regulation; Immunosuppressive Agents; Interferon-gamma; Interleukin-1; Interleukin-2; Myocarditis; Myosins; Natriuretic Peptide, Brain; Rats; Rats, Inbred Lew; Sirolimus; Treatment Outcome; Tumor Necrosis Factor-alpha

Congestive heart failure (CHF) results in decreased cardiac sympathetic innervation.. The purpose of this study was to test the hypothesis that therapy with the vasopeptidase inhibitor omapatrilat (OMA) attenuates cardiac neuronal remodeling in CHF.. We induced CHF in dogs with rapid ventricular pacing for 5 weeks with (CHF+OMA group, n = 8) or without (CHF group, n = 10) concomitant OMA treatment (10 mg/kg twice daily). Cardiac catheterization and echocardiography were performed to determine cardiac structure and hemodynamic parameters. Myocardial nerve density was determined by immunocytochemical staining with anti-growth associated protein 43 (GAP43) and anti-tyrosine hydroxylase (TH) antibodies. Seven normal dogs were used as histologic controls.. In the CHF group, ascites developed in 3 dogs and 4 dogs died, compared with no ascites or death in the CHF+OMA group (P = .07). In the 6 CHF dogs that survived, all had atrial fibrosis, severely depressed left ventricular systolic function, and increased atrial and ventricular chamber size. OMA treatment decreased the atrial and ventricular chamber sizes and the degree of atrial fibrosis. Most CHF dogs showed severe myocardial denervation, although some showed normal or abnormally high nerve counts. OMA treatment prevented heterogeneous reduction of nerve density. The left ventricular TH-positive nerve densities were 128 +/- 170 microm(2)/mm(2), 261 +/- 185 microm(2)/mm(2), and 503 +/- 328 microm(2)/mm(2) (P < .05), and the atrial GAP43-positive nerve densities were 1,683 +/- 1,365 microm(2)/mm(2), 305 +/- 368 microm(2)/mm(2), and 1,278 +/- 1,479 microm(2)/mm(2) (P < .05) for the control, CHF, and CHF+OMA groups, respectively.. CHF results in heterogeneous cardiac denervation. Long-term OMA treatment prevented the reduction of nerve density and promoted beneficial cardiac structural remodeling.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Atrial Natriuretic Factor; Cardiovascular Agents; Disease Models, Animal; Dogs; Heart Atria; Heart Failure; Heart Ventricles; Hypertrophy, Left Ventricular; Male; Myocardium; Natriuretic Peptide, Brain; Nerve Tissue; Pyridines; Renin; Stroke Volume; Thiazepines; Ventricular Dysfunction, Left; Ventricular Pressure; Ventricular Remodeling

The mechanisms of cardiac remodeling during chronic heart failure remain poorly defined. We sought to advance a chronic canine model of nonischemic cardiomyopathy.. Male dogs (n = 6) received decremental right ventricular apical tachypacing (12 months) to achieve and maintain stable left ventricular (LV) dysfunction. After 10 months of tachypacing, 120 beats/min was sufficient to maintain stable LV dysfunction. Electrocardiography, echocardiography, and tissue Doppler imaging were done to evaluate electrophysiology, LV dimensions and function, and dyssynchrony during normal sinus rhythm. The 6-minute walk test was used to evaluate functional capacity. We observed increases in both QRS duration (P < .0001) and QRS amplitude (P < .0001). LV fractional shortening was reduced from a baseline of 38.0 +/- 1.4% to 11.2 +/- 1.4% (P < .0001). LV end-diastolic dimension increased from 3.8 +/- 0.1 cm at baseline to 5.3 +/- 0.3 cm (P < .0001); LV end-systolic dimension increased from 2.3 +/- 0.1 cm to 4.7 +/- 0.2 cm (P < .0001). LV mass increased from 85.9 +/- 3.5 g at baseline to 179 +/- 13.7 g (P < .0001). There was evidence of LV dyssynchrony (P < .04) during both normal sinus rhythm and right ventricular tachypacing, compared with control dogs. The distance a dog walked in 6 minutes was significantly less at 12 months compared with normal controls (540 +/- 32 m versus 277 +/- 64 m, P < .008).. This nonischemic model of canine cardiomyopathy reproduces many aspects of chronic human heart failure including reduced fractional shortening, dilated ventricular dimensions, increased LV mass, decreased functional capacity, and dyssynchrony.

Topics: Animals; Biomarkers; C-Reactive Protein; Cardiomyopathies; Chronic Disease; Disease Models, Animal; Dogs; Echocardiography, Doppler; Electrocardiography; Heart Conduction System; Heart Rate; Humans; Hypertrophy, Left Ventricular; Male; Models, Cardiovascular; Natriuretic Peptide, Brain; Research Design; Stroke Volume; Time Factors; Troponin C; Troponin I; Ventricular Dysfunction, Left; Ventricular Remodeling

We established a rat chronic alveolar hypoxia in vivo model to evaluate the efficacy against hypoxic pulmonary hypertension of a new angiotensin II-receptor I blocker, olmesartan medoxomil. Three groups of rats were established: rats exposed for 2-6 weeks to 10% oxygen atmosphere in a normobaric chamber; hypoxic rats treated with olmesartan medoxomil oral administration (5 mg/day) every day; and control rats fed in a normoxic condition. After hypoxia treatment, the presence, etiology and severity of pulmonary hypertension, was echocardiographically evaluated, and expressions of brain natriuretic peptide (BNP), transforming growth factor (TGF-beta) and endothelin-1 genes measured by both immunohistochemical assay and real-time polymerase chain reaction. Olmesartan medoxomil significantly reduced the induction of hypoxic cor pulmonale not only on echocardiographical observations but also in BNP, TGF-beta and endothelin gene expressions in molecular studies. However, systolic blood pressure was independent of olmesartan medoxomil. The present study clearly indicates that the angiotensin II-type I-receptor blocker olmesartan medoxomil has significant efficacy for hypoxic cor pulmonale.

Topics: Administration, Oral; Angiotensin II Type 1 Receptor Blockers; Animals; Antihypertensive Agents; Collagen; Disease Models, Animal; Echocardiography; Endothelins; Heart; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Hypoxia; Imidazoles; Lung; Male; Myocardium; Natriuretic Peptide, Brain; Olmesartan Medoxomil; Pulmonary Artery; Pulmonary Heart Disease; Rats; Rats, Wistar; RNA, Messenger; Tetrazoles; Transforming Growth Factor beta

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

Studied were the effects of myocardial infarction (MI) on mild renal function loss in unilateral nephrectomized (UnX) rats. UnX was performed, followed after 1 wk by a variable MI (UnX + MI; n = 24). Rats with only UnX (n = 15) or MI (n = 9) and double sham animals (CON, n = 15) served as controls. Renal outcome was measured by proteinuria and plasma creatinine. Focal glomerulosclerosis (FGS) incidence was evaluated by renal histology. Cardiac function and systolic BP were measured. A division into small and large infarcts after UnX was made a priori, resulting in two groups, one with a mild MI (<20%; n = 15) and one with a moderate MI (>20%; n = 9). Mild proteinuria up to 55.5 mg/d was observed in the UnX + mild MI group, whereas proteinuria rose significantly higher to 124.5 mg/d in the UnX + moderate MI group. Incidence of FGS was significantly increased in both UnX + MI groups compared with all other groups. The average MI size was 18%, 17%, and 25% in the MI, UnX + mild MI, and UnX + moderate MI group, respectively. LVP in both UnX + MI groups was correlated with proteinuria, indicative of a cardio-renal interaction. Clinically, these data imply that more patients are at risk for cardiovascular events and that after such an event, their chance of more renal function loss increases. Finding the underlying mechanism will enable improved protection for both kidneys and heart.

Topics: Animals; Creatinine; Disease Models, Animal; Glomerulosclerosis, Focal Segmental; Heart; Kidney; Male; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain; Nephrectomy; Organ Size; Proteinuria; Rats; Rats, Wistar; Risk Factors; Survival Rate

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

Heart failure is known for alteration of cardiac catecholamine responsiveness involving adrenergic receptor (AR) down-regulation. Trimetazidine, a metabolically active anti-ischemic drug, accelerates the turnover of phospholipids. The present study evaluated the consequences of trimetazidine treatment (supposed to increase phospholipid synthesis) on AR in heart failure in rats. In control rats, trimetazidine (7.5 mg/day supplied in the diet) induced after 8 weeks a significant increase in both beta- (+54%) and alpha-AR (+30%) density, although after 12 weeks, the receptor density was normalized. Heart failure was obtained by ascending aortic banding. These heart failure rats developed a severe cardiac hypertrophy, mainly affecting the left ventricle, which was significantly reduced in the trimetazidine-treated group. The plasma level of brain natriuretic peptide (BNP), a marker of heart failure severity, was significantly increased in the heart failure group as compared with the sham group (900 and 1200% after 8 and 12 weeks, respectively). In the trimetazidine-treated group, the plasma BNP increase was significantly lower. The development of heart failure was associated with a decrease in beta- and alpha-AR sites (-23 and -36% versus sham, respectively) after 8 weeks and continued to decrease after 12 weeks (-37 and -48% versus sham, respectively). This down-regulation was prevented by trimetazidine without alteration in affinity. These results suggest that trimetazidine prevents AR desensitization and cardiac hypertrophy, in a pressure-overload model of heart failure. This cytoprotection suggests that membrane homeostasis preservation may be considered as a therapeutic target in the treatment of heart failure.

Topics: Animals; Disease Models, Animal; Heart Failure; Male; Natriuretic Peptide, Brain; Organ Size; Phospholipids; Rats; Rats, Wistar; Receptors, Adrenergic; Trimetazidine; Vasodilator Agents

Angiotensin II plays a prominent role in the progression of heart failure after acute myocardial infarction (AMI). Although both angiotensin type 1 (AT1) and type 2 (AT2) receptors are known to be present in the heart, comparatively little is known about the latter. We therefore examined the role played by AT2 receptors in post-AMI heart failure.. In wild-type mice subjected to AMI by coronary artery ligation, AT2 receptor immunoreactivity is upregulated in the infarct and border areas. Among AT2 receptor-null (-/-) mice, the 7-day survival rate after AMI was significantly lower than among wild-type mice (43% versus 67%; P<0.05). All sham-operated animals of both genotypes survived through the study. Ventricular mRNA levels for brain natriuretic peptide were elevated in both genotypes 24 hours after coronary occlusion, with levels in AT2-/- significantly higher than in wild-type mice, as were their lung weights, and histological examination revealed marked pulmonary congestion in the AT2-/- mice. Cardiac function was significantly decreased in AT2-/- mice 2 days after AMI.. AT2 receptor deficiency exacerbates short-term death rates and heart failure after experimental AMI in mice. The AT2 receptor may thus exert a protective effect on the heart after AMI.

Topics: Acute Disease; Animals; Disease Models, Animal; Disease Progression; Echocardiography; Electrocardiography; Female; Heart Failure; Homozygote; Ligation; Mice; Mice, Knockout; Myocardial Infarction; Natriuretic Peptide, Brain; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Receptors, Angiotensin; RNA, Messenger; Severity of Illness Index; Survival Rate

Both cardiotrophin-1 (CT-1) and B-type or brain natriuretic peptide (BNP) are activated by cardiomyocyte stretch, and gene expression of CT-1 and BNP are augmented in the heart in experimental and human congestive heart failure (CHF). The goal of this study was to define cardiac gene expression of CT-1 and BNP by Northern blot analysis in normal (n=5), early left ventricular dysfunction (ELVD, n=5) and overt CHF dogs (n=5), in which ventricular function is progressively decreased. CT-1 mRNA was detected in both atria and ventricles in normal dogs. Ventricular CT-1 mRNA production increased in ELVD, and it further increased in overt CHF. Ventricular BNP mRNA remained below or at the limit of detection in normal and ELVD models, and it markedly increased in overt CHF. This study reports differential regulation of gene expression of CT-1 and BNP in the heart during the progression of CHF, and demonstrates that ventricular CT-1 gene activation precedes ventricular BNP gene activation.

Topics: Animals; Blood Pressure; Cytokines; Disease Models, Animal; Dogs; Enzyme Activation; Heart Failure; Heart Ventricles; Male; Natriuretic Peptide, Brain; RNA, Messenger

Growing evidence suggests that the autoimmune mechanism plays an important role in the pathogenesis of dilated cardiomyopathy. The purpose of this study was to evaluate the effect on the cardiac structure and function by the transfer of immunoglobulin G (IgG) and/or lymphocytes from rabbits immunized with a synthetic peptide corresponding to the sequence of the second extracellular loop of beta1-adrenoceptor (beta peptide) into severe combined immunodeficiency (SCID) mice. CB-17 SCID mice were injected intraperitoneally with 2 mg of IgG and/or 1 x 10(7) peripheral blood lymphocytes (PBL) from either rabbits immunized with both beta1 peptide and adjuvant (beta group), and adjuvant or rabbits with adjuvant only (N group). Thirty-five SCID mice were divided into seven groups: (1) N-IgG group; (2) N-PBL group; (3) N-IgG+PBL group; (4) beta-IgG group; (5) beta-PBL group; (6) beta-IgG+PBL group; and (7) control group. Morphological, serological and endocrinological studies were performed 70 days after the transfer. Results showed that heart weight and heart weight/body weight ratio in the beta-IgG+PBL group tended to be increased as compared with those in other groups. All mice in the beta-IgG group, two in the beta-PBL group and four in the beta-IgG+PBL group showed high titer of rabbit anti-beta1-adrenoceptor antibodies. Brain natriuretic peptide in the beta-IgG+PBL group showed a significant increase as compared with those in the control group and N-IgG+PBL. Pathohistologically, focal infiltration of inflammatory cells in the myocardium was observed in one mouse of the beta-IgG+PBL group. Rabbit CD3-positive T-lymphocytes in the myocardium were observed in two mice of the beta group. In conclusion, transfer of IgG and PBL from rabbits immunized with beta1 peptide was able to induce the early stages of myocardial damage in SCID mice. These data provide direct evidence that the autoimmune mechanism is important in the pathogenesis of dilated cardiomyopathy.

Topics: Adoptive Transfer; Animals; Autoantibodies; Autoimmune Diseases; Body Weight; Cardiomyopathies; Disease Models, Animal; Female; Heart; Immunoglobulin G; Injections, Intraperitoneal; Lymphocyte Transfusion; Male; Mice; Mice, SCID; Myocardium; Natriuretic Peptide, Brain; Organ Size; Rabbits; Receptors, Adrenergic, beta-1; Severe Combined Immunodeficiency; T-Lymphocytes

Short-term administration of adrenomedullin, a recently discovered peptide with potent vasodilator, natriuretic, and aldosterone-inhibitory actions, has beneficial effects in experimental and clinical heart failure. The effects of prolonged adrenomedullin administration have not previously been assessed in this setting. Consequently, in 16 sheep with pacing-induced heart failure, we infused either adrenomedullin (10 ng/kg per minute; n=8) or a vehicle control (Hemaccel; n=8) for 4 days. Compared with control data, infusion of adrenomedullin persistently increased circulating levels of the peptide (by approximately 9.5 pmol/L; P<0.001), in association with prompt (15 minutes) and sustained (4 days) increases in cardiac output (day 4, 27%), and reductions in peripheral resistance (30%), mean arterial pressure (13%), and left atrial pressure (24%; all, P<0.001). Adrenomedullin also significantly enhanced urinary sodium excretion (day 4, 3-fold; P<0.05), creatinine excretion (1.2-fold; P<0.001), and creatinine clearance (1.4-fold; P<0.001) over the 4 days of treatment, whereas urine volume and cAMP excretion tended to be elevated (both, 0.1>P>0.05). Plasma renin activity was increased (P<0.05), whereas aldosterone levels were reduced in a sustained fashion (P<0.01). Plasma endothelin rose transiently (hours 1 to 6) after initiation of treatment (P<0.05). Despite substantial cardiac unloading, plasma concentrations of the natriuretic peptides were not significantly different from control. In conclusion, long-term administration of adrenomedullin induces pronounced and sustained cardiovascular and renal effects in experimental heart failure, including reductions in cardiac preload and afterload, as well as augmentation of cardiac output, sodium excretion, and glomerular filtration. These findings support the concept of adrenomedullin as a protective hormone during hemodynamic compromise with therapeutic potential in heart failure.

Topics: Adrenomedullin; Aldosterone; Animals; Atrial Natriuretic Factor; Blood Pressure; Cardiac Output; Cardiac Pacing, Artificial; Cyclic AMP; Disease Models, Animal; Endothelins; Female; Heart Failure; Hemodynamics; Hydrocortisone; Infusions, Intravenous; Kidney; Natriuretic Peptide, Brain; Peptides; Renin; Sheep; Time; Treatment Outcome; Vascular Resistance

A hallmark of congestive heart failure (CHF) is the elevation of the cardiac natriuretic peptides (NPs), which have natriuretic, renin-inhibiting, vasodilating, and lusitropic properties. We have reported that chronic subcutaneous (SQ) administration of brain natriuretic peptide (BNP) in experimental CHF improves cardiorenal function. Vasopeptidase inhibitors (VPIs) are single molecules that simultaneously inhibit both neutral endopeptidase 24.1 (NEP) and ACE. We hypothesized that acute VPI administration would potentiate the cardiorenal actions of SQ BNP in experimental CHF.. We determined the cardiorenal and humoral responses to acute VPI alone with omapatrilat (OMA) (1 micromol/kg IV bolus) (n=6), acute low-dose SQ BNP (5 microg/kg) alone (n=5), acute VPI plus low-dose SQ BNP (n=5), and acute high-dose SQ BNP (25 microg/kg) alone in 4 groups of anesthetized dogs with experimental CHF produced by ventricular pacing for 10 days. Plasma BNP was greater with VPI+low-dose SQ BNP compared with VPI alone or low-dose SQ BNP alone and was similar to high-dose SQ BNP alone. Urinary BNP excretion was greatest with VPI+SQ BNP. Urinary sodium excretion was also highest with VPI+SQ BNP, with the greatest increase in glomerular filtration rate. VPI+SQ BNP resulted in a greater increase in cardiac output and reduction in cardiac filling pressures as compared with low-dose SQ BNP, high-dose SQ BNP, or VPI alone.. This study reports that acute VPI potentiates the cardiorenal actions of SQ BNP in experimental CHF. This study advances the concept that protein therapy with BNP together with vasopeptide inhibition represents a novel therapeutic strategy in CHF to maximize the beneficial properties of the natriuretic peptide system.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Atrial Natriuretic Factor; Cardiac Pacing, Artificial; Cyclic GMP; Disease Models, Animal; Dogs; Dose-Response Relationship, Drug; Glomerular Filtration Rate; Heart Failure; Hemodynamics; Injections, Subcutaneous; Kidney; Male; Natriuretic Peptide, Brain; Neprilysin; Peptidyl-Dipeptidase A; Pyridines; Sodium; Thiazepines

The purpose of this study was to examine the effects of nipradilol on the cardiac function and mRNA expression in Wistar rats with a myocardial infarction (MI) that was created by ligation of the anterior descending coronary. Ten mg x kg(-1) x day(-1) of nipradilol were administrated to the rats in random order, and hemodynamic and Doppler-echocardiographic findings and myocardial mRNA expression were analyzed at 4 weeks after MI. Although left ventricular end-diastolic pressure (LVEDP) and central venous pressure (CVP) were increased in the MI rats, nipradilol significantly reduced the degree of the increase in both parameters. MI also significantly increased the weight of the left and right ventricles, and increased the left ventricular end-diastolic dimension (LVDd), effects that were attenuated by nipradilol. The MI rats showed decreased fractional shortening as systolic dysfunction and decreased E wave deceleration rate as diastolic dysfunction, and nipradilol significantly prevented these. Nipradilol significantly suppressed the increase in the non-infarcted myocardial mRNA expression of atrial natriuretic peptide, brain natriuretic peptide and collagen I and III. In conclusions, nipradilol prevents the cardiac remodeling that is accompanied by systolic and diastolic dysfunction, and inhibits abnormal myocardial gene expression after MI.

Topics: Adrenergic beta-Antagonists; Animals; Atrial Natriuretic Factor; Biomarkers; Collagen Type I; Collagen Type III; Disease Models, Animal; Echocardiography, Doppler; Myocardial Infarction; Natriuretic Peptide, Brain; Propanolamines; Rats; Rats, Wistar; RNA, Messenger; Ventricular Dysfunction, Left; Ventricular Remodeling

Many studies have suggested that the renin-angiotensin system plays an important role in the left ventricular (LV) remodeling and cardiac dysfunction that occurs after myocardial infarction (MI). Although angiotensin II type IA (AT1A) receptor knockout (KO) mice are reported to display less LV remodeling after MI, diastolic dysfunction has not been fully evaluated, so the present study measured transmitral inflow pattern in both AT1A receptor KO mice with MI (KO-MI) and wild type mice with MI (WT-MI). Cardiac geometry and function were examined by Doppler echocardiography and myocardial mRNA expression was determined by Northern blot analysis at 4 weeks after MI. The LV internal diastolic dimension of WT-MI was larger than that of the KO-MI (p<0.05). Marked increases in the E wave velocity and the ratio of the peak velocity of the E wave to the A wave were observed in the WT-MI (p<0.01). The deceleration rate of the E wave in KO-MI was lower than in WT-MI (p<0.05). mRNA expressions of ANP, BNP, collagen I and collagen III in the non-infarcted LV and RV of KO-MI were significantly lower than WT-MI. In conclusion, transmitral inflow abnormalities in KO-MI were attenuated compared with WT-MI.

Topics: Animals; Atrial Natriuretic Factor; Collagen Type I; Collagen Type III; Coronary Circulation; Disease Models, Animal; Echocardiography, Three-Dimensional; Gene Expression Regulation; Hemodynamics; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitral Valve; Myocardial Infarction; Natriuretic Peptide, Brain; Receptor, Angiotensin, Type 1; Receptors, Angiotensin; Transcription, Genetic

Hyponatremia after subarachnoid hemorrhage has been linked to high plasma concentration of atrial natriuretic peptide and brain natriuretic peptide. Volume expansion therapy to prevent symptomatic vasospasm, such as intensive hypertensive and hypervoremic therapy, may alter systemic concentration of these peptides. We therefore examine brain natriuretic peptide secretion in rats in response to acute volume expansion, infusing to 10 ml of saline over 1 h. In the 10 ml group, brain natriuretic peptide concentrations showed a significant increase from pre-infusion concentrations 1 h after initiation of infusion, but had begun to fall 1 h later. We suspect that high plasma concentration of brain natriuretic peptide after subarachnoid hemorrhage is partly caused by hypervoremic therapy.

Topics: Animals; Blood Volume; Brain; Disease Models, Animal; Hyponatremia; Male; Natriuretic Peptide, Brain; Plasma Substitutes; Rats; Rats, Wistar; Sodium Chloride; Subarachnoid Hemorrhage; Vasospasm, Intracranial; Water-Electrolyte Balance

Transthoracic echocardiography was used in a rodent animal model to determine whether long-term alcohol consumption (8 and 12 months) was associated with the development of a dilated cardiomyopathy. We also investigated whether alcohol-induced changes in cardiac structure corresponded to activation of the renin-angiotensin system and the natriuretic peptide (NP) system.. Male rats received either the Lieber-DeCarli liquid alcohol diet (EtOH) (9%v/v) (n = 8) or control diet (CON) (n = 8). Echocardiography (echo) was used to determine left-ventricular (LV) dimensions, and isolated heart studies (Langendorff and atrium) were used to assess ex vivo contractility. Plasma and tissue angiotensin-I converting enzyme (ACE) activity was measured. Gene expression, plasma, and tissue levels of the NPs were determined by northern blot analysis and radioimmunoassay, respectively.. After 8 months of alcohol consumption, there was a trend for the end diastolic dimension, end systolic dimension, and LV mass to be greater in the 8 month EtOH group compared with the CON group. However, after 12 months of alcohol consumption, significant increases were found between the groups in several echo parameters. Tissue ACE activity (nmoles/min/mg protein) was greater in the 12 month EtOH group compared with the 12 month CON and 8 month EtOH group (p < 0.05). We found no differences between groups in gene expression (messenger RNA), plasma, and tissue levels of the NPs.. Echocardiography revealed that 8 to 12 months of alcohol consumption was associated with the development of a dilated cardiomyopathy. However, this was not preceded by an increase in tissue ACE activity, and these changes occurred in the absence of increased plasma and LV tissue levels of the NPs.

Topics: Alcoholism; Animals; Atrial Natriuretic Factor; Cardiomyopathy, Alcoholic; Disease Models, Animal; Echocardiography; Male; Myocardium; Natriuretic Peptide, Brain; Peptidyl-Dipeptidase A; Rats; Rats, Sprague-Dawley; Stroke Volume

The role of load versus angiotensin II (Ang II) and endothelin-1 (ET) in the pathogenesis of hypertensive heart disease is controversial. We sought to determine whether alterations in cardiac structure and function due to hypertension (HTN) were dependent on Ang II or ET activation. Methods and Results-- Bilateral renal wrapping to produce HTN (n=12) or sham surgery (n=6) was performed in adult dogs. Weekly blood pressure, plasma renin activity, Ang II, ET, and catecholamines were measured. Systolic (end-systolic elastance, Ees) and diastolic (tau) function were assessed in sham and HTN dogs at 5 (HTN-5wk) or 12 (HTN-12wk) weeks. Ang II and ET were assayed in the left ventricle (LV) and kidney. Mean arterial pressure was higher in renal wrap dogs at week 1 (*P<0.05 versus controls: 139+/-4* versus 123+/-4 mm Hg), week 5 (174+/-7* versus 124+/-4 mm Hg), and week 12 (181+/-12* versus 124+/-4 mm Hg). LV mass index was increased in HTN-5wk (22%*) and HTN-12wk (39%*). LV fibrosis was increased in HTN-12wk. Ees was preserved in HTN-5wk and HTN-12wk. tau was increased in HTN-5wk (50+/-3* ms) and HTN-12wk (62+/-10* ms) dogs compared with sham (41+/-2 ms). Plasma Ang II, ET, catecholamines, and plasma renin activity were unchanged during the progressive HTN. Ang II and ET in LV and kidney were not different from controls.. Systemic HTN induces LV hypertrophy, myocardial fibrosis, and isolated diastolic dysfunction in the absence of local or systemic activation of Ang II or ET. These findings suggest that load is the prevailing stimulus for the structural and functional changes associated with early hypertensive heart disease.

Topics: Angiotensin II; Animals; Catecholamines; Diastole; Disease Models, Animal; Dogs; Endothelin-1; Heart Ventricles; Hemodynamics; Hypertension; Hypertrophy, Left Ventricular; Kidney; Natriuretic Peptide, Brain; Propranolol; Renin; Systole; Ventricular Dysfunction, Left

Activation of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) is considered a hallmark of myocardial remodeling. To determine magnitude and relative proportion of activation during the progression to heart failure, we assessed ANP and BNP gene expression in atrial and left ventricular (LV) tissue in a newly developed model of progressive rapid ventricular pacing-induced heart failure in rabbits.. Six animals underwent progressive pacing with incremental rates (330 beats per min (bpm) to 380 bpm over 30 days), resulting in congestive heart failure (CHF). Five animals underwent pacing at 330 bpm for 10 days only (early LV dysfunction, ELVD) and five additional animals served as control group (CTRL).. ELVD was characterized by decreased mean arterial pressure (P=0.05 vs. CTRL) as well as significantly impaired LV function (LV fractional shortening (FS) P<0.01 vs. CTRL) and dilatation (P<0.01 vs. CTRL). CHF was characterized by further decreased mean arterial pressure (P<0.01 vs. ELVD), further impaired LV function (FS P<0.03 vs. ELVD) and dilatation (P<0.01 vs. CTRL). In control animals, significant ANP expression was observed only in atrial tissue (P<0.02 vs. BNP) while BNP expression was ubiquitous but marginal (LV P<0.05 vs. ANP). In ELVD, activation of ANP (atria and LV P<0.05 vs. CTRL) and BNP (atria P<0.05 vs. CTRL, LV n.s.) was observed. In CHF, LV-BNP increased further markedly (P<0.01 vs. CTRL, P<0.05 vs. ELVD) while atrial ANP and BNP expression as well as LV ANP expression remained unchanged (all P=n.s. vs. ELVD).. The current studies demonstrate differential activation of atrial and LV ANP and BNP under normal conditions and during the progression to heart failure and provide a molecular basis for the superiority of BNP as marker of LV dysfunction and CHF.

Topics: Animals; Atrial Natriuretic Factor; Blood Pressure; Body Weight; Disease Models, Animal; Disease Progression; Gene Expression; Heart Failure; Male; Myocardium; Natriuretic Peptide, Brain; Organ Size; Rabbits; RNA, Messenger; Ventricular Dysfunction, Left

Long term effects of left ventricle (LV) repair surgery (LVR) for ischemic cardiomyopathy are not well understood.. Sixty-nine rats developed ischemic cardiomyopathy with large akinetic LV area 4 weeks after the left anterior descending artery was ligated. In a second surgery 4 weeks later, 33 rats underwent LVR by plication of the akinetic LV area (LVR group), and 36 underwent rethoracotomy alone (sham group). No medication was used in either group. All rats survived the second surgery. LV end-diastolic dimension as measured by echocardiography, LV fractional shortening, and the maximal end-systolic pressure-volume relationship (E(max)) as calculated from the data by catheter-tipped manometer and echocardiography improved in the LVR group after the second surgery, but LV end-diastolic dimension and E(max) gradually deteriorated as time passed. LV end-diastolic pressure improved 1 week after LVR but rose significantly 4 weeks after LVR. Brain natriuretic peptide mRNA was lower in the LVR group than in the sham group 1 week after LVR but not 4 weeks postoperatively.. Initial improvement in LV function and neurohormonal status after LVR did not last for 4 weeks in this rat model when untreated medically. The mechanism of deterioration should be elucidated to improve long-term results of LVR.

Topics: Animals; Cardiac Surgical Procedures; Cardiomyopathies; Disease Models, Animal; Disease Progression; Echocardiography; Heart Ventricles; Hemodynamics; Male; Myocardial Ischemia; Myocardium; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley; RNA, Messenger; Stroke Volume; Time; Treatment Failure; Ventricular Dysfunction, Left

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

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

Experimental pulmonary hypertension induced in a hypobaric hypoxic environment (HHE) is characterized by structural remodeling of the heart and pulmonary arteries. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) both have diuretic, natriuretic, and hypotensive effects, and both are involved in cardiovascular homeostasis as cardiac hormones. To study the effects of HHE on the natriuretic peptide synthesis system, 170 male Wistar rats were housed in a chamber at the equivalent of the 5500-m altitude level for 1-12 weeks. After 1 week of HHE, pulmonary arterial pressure was significantly raised, and the ratio of left ventricle plus septum over right ventricle of the heart showed a significant decrease (compared with those of ground-level control rats). In both ventricular tissues, the expression of ANP messenger (m)RNA and BNP mRNA increased after exposure to HHE. The amounts of ANP and BNP had decreased significantly in right atrial tissue at 12 weeks of HHE (compared with those of the controls), whereas in ventricular tissues at the same time point, both levels had increased significantly. In in situ hybridization and immunohistochemical studies, the staining of the mRNAs for ANP and BNP and of ANP and BNP themselves was more intense in both ventricular tissues after exposure to HHE than before (i.e., in the controls). The results suggest that, in response to HHE, the changes in ventricular synthesis are similar for ANP and BNP. These changes may play a role in modulating pulmonary hypertension in HHE. However, under our conditions, pulmonary hypertension increased progressively throughout the HHE period.

Topics: Altitude Sickness; Animals; Atmosphere Exposure Chambers; Atmospheric Pressure; Atrial Natriuretic Factor; Blotting, Northern; Disease Models, Animal; Fluorescent Antibody Technique, Indirect; Heart Ventricles; Hypertension, Pulmonary; Hypertrophy, Left Ventricular; Immunoenzyme Techniques; In Situ Hybridization; Male; Myocardium; Natriuretic Peptide, Brain; Rats; Rats, Wistar; RNA, Messenger; Time Factors

Clinical heart failure, often the result of myocardial infarction, may be preceded by a period of compensated left ventricular impairment. There is substantial need for an experimental model that reflects this human condition. In sheep, coronary artery ligation produced consistent left ventricular anteroapical myocardial infarctions resulting in chronic (5 wk), stable hemodynamic changes compared with sham controls, including reductions in ejection fraction (51 +/- 2 vs. 30 +/- 5%, P < 0.001), cardiac output (6.3 +/- 0.2 vs. 5.1 +/- 0.2 l/min, P < 0.01), and arterial pressure (93 +/- 2 vs. 79 +/- 3 mmHg, P < 0.001), and increases in cardiac preload (left atrial pressure, 3.3 +/- 0.1 vs. 8.3 +/- 1.3 mmHg, P < 0.001). These changes were associated with acute and sustained increases in plasma concentrations of atrial natriuretic peptide (ANP; 5 wk, 11 +/- 2 vs. 27 +/- 5 pmol/l, P < 0.001), brain natriuretic peptide (BNP; 3 +/- 0.2 vs. 11 +/- 2 pmol/l, P < 0.001), and amino-terminal pro-brain natriuretic peptide (NT-BNP; 17 +/- 3 vs. 42 +/- 12 pmol/l, P < 0.001). Significant correlations were observed between plasma levels of the natriuretic peptides (ANP, day 7 to week 5 samples; BNP and NT-BNP, day 1 to week 5 samples) and changes in left ventricular volumes and ejection fraction. In contrast, renin activity, aldosterone, catecholamines, and endothelin were not chronically elevated postinfarction and were not related to indexes of ventricular function. Coronary artery ligation in sheep produces the pathological, hemodynamic, and neurohormonal characteristics of compensated left ventricular impairment secondary to myocardial infarction. Plasma concentrations of the cardiac natriuretic peptides are sensitive markers of left ventricular dysfunction. This is a reproducible model that reflects the clinical condition and should prove suitable for investigating the pathophysiology of, and experimental therapies in, early left ventricular dysfunction.

Topics: Aldosterone; Animals; Atrial Natriuretic Factor; Coronary Vessels; Disease Models, Animal; Endothelin-1; Epinephrine; Female; Hemodynamics; Ligation; Myocardial Infarction; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Neuropeptides; Norepinephrine; Peptide Fragments; Renin; Sheep; Ventricular Dysfunction, Left

Omapatrilat is a member of the new drug class of vasopeptidase inhibitors that may offer benefit in the treatment of heart failure (HF) through simultaneous inhibition of angiotensin-converting enzyme and neutral endopeptidase. We examined the effects of omapatrilat in a placebo-controlled crossover study using a pacing model of HF. Seven sheep were paced sequentially at 180 bpm (mild HF) and then 225 bpm (severe HF) for 7 days each. Omapatrilat (0.005 mg/kg) or vehicle was administered by intravenous bolus on days 4 to 7 of each paced period. Omapatrilat lowered mean arterial and left atrial pressure and increased cardiac output acutely and chronically in both mild and severe HF (P<0.01 for all). Plasma atrial and brain natriuretic peptide and cGMP levels were stable acutely (P=NS), while brain natriuretic peptide increased after repeated dosing in severe HF (P<0.05). Plasma renin activity rose, whereas angiotensin II and aldosterone levels fell after acute and repeated dosing in both states (P<0.01 for all). Omapatrilat increased urinary sodium excretion by day 7 in both mild and severe HF (P<0.05). Effective renal plasma flow and glomerular filtration rate increased or were stable after omapatrilat in mild and severe HF after both acute and repeated dosing. Omapatrilat exhibited pronounced acute and sustained beneficial hemodynamic and renal effects in both mild and severe heart failure.

Topics: Aldosterone; Angiotensin II; Animals; Atrial Natriuretic Factor; Blood Pressure; Cardiac Output; Cardiovascular Agents; Cross-Over Studies; Cyclic GMP; Disease Models, Animal; Glomerular Filtration Rate; Heart Failure; Hemodynamics; Injections, Intravenous; Kidney; Natriuretic Peptide, Brain; Pyridines; Renin; Sheep; Sodium; Thiazepines

We studied the role of angiotensin II in pressure overload-induced B-type natriuretic peptide (BNP) gene expression by using a double transgenic rat (dTGR) model, in which transgenic rats for the human angiotensinogen and renin genes are crossed. Pressure overload produced by [Arg8]-vasopressin (AVP) infusion (i.v., 0.05 microg/kg/min for 2 h) in conscious, chronically instrumented rats, resulted in a significantly greater increase in BNP mRNA levels in the left atrium of the dTGR rats than in Sprague-Dawley (SD) control rats (3.6- vs 1.6-fold, p < 0.05), while in the left ventricle there was no significant difference between the strains. In dTGR rats, the early activation of the BNP gene expression was associated with a decrease in immunoreactive BNP levels in the atrium (27.5%, p < 0.05), but not in the ventricle. In SD rats, ir-BNP levels did not change significantly in either atria or ventricles in response to AVP infusion. These results show that the pressure overload-induced activation of BNP gene expression differs between atrial and ventricular myocytes in the dTGR model of experimental hypertension.

Topics: Angiotensinogen; Animals; Animals, Genetically Modified; Atrial Natriuretic Factor; Blood Pressure; Disease Models, Animal; Gene Expression; Heart Atria; Humans; Hypertension; Male; Natriuretic Peptide, Brain; Rats; Rats, Sprague-Dawley; Renin; RNA, Messenger

Following myocardial Infarction (MI) the heart undergoes a process of remodeling characterized by considerable hypertrophy of the non-infarcted myocardium. We have recently characterized the molecular basis of key electrophysiologic alterations that may provide insight into the arrhythmogenecity of post-MI remodeled hypertrophied myocardium. To further characterize other key alterations in the pattern of cardiac gene expression in a time-dependent manner, we have measured mRNA and immunoreactive protein levels of selective cardiac genes in the remodeled hypertrophied left-ventricular (LV) myocardium of rats, 3 and 21 days after left-coronary ligation and compared the results with sham-operated rats. RNase protection assay was performed to assess the expression of c-fos, atrial natriuretic factor (ANF), brain natriuretic factor (BNF), alpha2/3 isoform of Na-K ATPase, cardiac alpha/beta isoform of myosin heavy chain (MHC). Compared to the sham group, the expression of c-fos was increased 10-fold (P<0.02) in the MI group on day 3, but unlike other overload hypertrophy models, the expression remained elevated by three-fold on day 21. Similar to other overload models, the ANF and BNF expression increased significantly. No alterations were observed in the expression of cardiac alpha-actin. There was reexpression of the fetal isogene form of MHC and Na-K ATPase after MI. The beta-MHC mRNA levels, the fetal isoform of MHC, returned to basal levels after 21 days. After an initial five-fold decrease the adult isoform of alphaNa-K ATPase, alpha2 Na-K ATPase mRNA, returned to control levels and similar changes were seen in the corresponding protein levels. These findings indicate that during LV remodeling and hypertrophy following MI, there is an upregulation of early response genes and fetal isogene expression. The pattern of activation, however, is distinct from that observed in other overload models, indicating the possible involvement of alternate signal transduction pathways.

Topics: Animals; Atrial Natriuretic Factor; Base Sequence; Disease Models, Animal; DNA Primers; Electrophysiology; Female; Gene Expression; Genes, fos; Hypertrophy, Left Ventricular; Myocardial Infarction; Myosin Heavy Chains; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Polymerase Chain Reaction; Rats; Rats, Sprague-Dawley; RNA, Messenger; Signal Transduction; Sodium-Potassium-Exchanging ATPase

We compared the effects of natriuretic peptides on antigen-induced bronchoconstriction and airway microvascular leakage in sensitized guinea pigs. Anesthetized male guinea pigs, ventilated via a tracheal cannula, were placed in a plethysmograph to measure pulmonary mechanics for 10 min after challenge with 1 mg/kg of ovalbumin, and then Evans blue dye was extravasated into airway tissue in order to indicate and evaluate microvascular leakage. Three separate intravenous pretreatments using atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP) significantly inhibited the ovalbumin-induced bronchoconstriction and microvascular leakage in a dose-dependent manner. These inhibitory effects were mimicked by 8-bromoguanosine 3',5'-cyclic monophosphate. We showed that the rank order of inhibitory potencies, which were mediated by cyclic guanosine 3',5'-monophosphate, was BNP > or = ANP > or = CNP. These results gave us some clues for the clinical application of the natriuretic peptides.

Topics: Animals; Antigens; Asthma; Atrial Natriuretic Factor; Blood Pressure; Bronchi; Bronchoconstriction; Capillary Permeability; Cyclic GMP; Disease Models, Animal; Guinea Pigs; Leukotriene D4; Male; Natriuretic Peptide, Brain; Natriuretic Peptide, C-Type; Nerve Tissue Proteins; Ovalbumin; Proteins; Trachea

In a model of acute ischaemic left ventricular failure in pigs, we compared the plasma levels and cardiac secretion of the three atrial peptides, atrial natriuretic factor (ANF), N-terminal proatrial natriuretic factor (N-terminal proANF) and brain natriuretic peptide (BNP). Acute ischaemic left ventricular failure was induced by embolization of the left coronary artery with plastic microspheres. Thereafter, treatment was given by an intravenous injection of the angiotensin II receptor (AT1) antagonist losartan. Effects of failure induction and treatment were documented by measurement of haemodynamic parameters and plasma concentrations of catecholamines, plasma renin activity, angiotensin II and aldosterone. Acute left ventricular failure was accompanied by significant increases in cardiac secretion and plasma levels of all three atrial peptides, which was considerably more pronounced for ANF and N-terminal proANF than for BNP. Treatment with losartan resulted in significant decreases in plasma ANF and N-terminal proANF, whereas BNP did not change. These findings indicate that ANF and N-terminal proANF may be better suited than BNP as markers of cardiac preload during the development and treatment of acute heart failure.

Topics: Acute Disease; Angiotensin II Type 1 Receptor Blockers; Angiotensin Receptor Antagonists; Animals; Atrial Natriuretic Factor; Biomarkers; Disease Models, Animal; Embolism; Female; Heart; Heart Failure; Losartan; Male; Microspheres; Myocardial Ischemia; Myocardium; Natriuretic Peptide, Brain; Protein Precursors; Swine

1. We investigated the regulation of the atrial natriuretic peptide and brain natriuretic peptide genes in a rat model of myocardial infarction induced by isoproterenol (IP rat) and in a rat model of cardiac hypertrophy induced by aorto-caval shunt (AC shunt rat). 2. Brain natriuretic peptide (BNP) mRNA levels in atria were significantly higher in IP rats than in controls at 18 h after the administration of isoproterenol, but not significant increases were observed in atrial natriuretic peptide (ANP) mRNA expression levels at any time point examined. In the ventricles, the BNP mRNA levels peaked at 18 h after isoproterenol administration, whereas ANP mRNA levels gradually increased until 3 days after isoproterenol administration. 3. The BNP mRNA levels in both atria and ventricles were significantly increased at 1 day after the introduction of aorto-caval shunt, while the ANP mRNA levels were not. 4. Plasma BNP levels were closely correlated with left ventricular weight per bodyweight, in both IP rats and AC shunt rats. 5. These results suggest the differential regulation of ANP and BNP genes in both the atria and ventricles in these two pathological models.

Topics: Animals; Atrial Natriuretic Factor; Creatine Kinase; Disease Models, Animal; Gene Expression Regulation; Heart Ventricles; Isoproterenol; Male; Myocardial Infarction; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Organ Size; Rats; Rats, Sprague-Dawley; Ventricular Function

Ischaemic stroke is a complex disorder caused by a combination of genetic and environmental factors. Clinical and epidemiological studies have provided strong evidence for genetic influences in the development of human stroke and several mendelian traits featuring stroke have been described. The genetic analysis of the non-mendelian, common ischaemic stroke in humans is hindered by the late onset of the disease and the mode of inheritance, which is complex, polygenic and multifactorial. An important approach to the study of such polygenic diseases is the use of appropriate animal models in which individual contributing factors can be recognized and analysed. The spontaneously hypertensive stroke-prone rat (SHRSP) is an experimental model of stroke characterized by a high frequency of spontaneous strokes as well as an increased sensitivity to experimentally induced focal cerebral ischaemia. Rubattu et al. performed a genomewide screen in an F2 cross obtained by mating SHRSP and SHR, in which latency to stroke on Japanese rat diet was used as a phenotype. This study identified three major quantitative trait loci (QTLs), STR-1-3. Of these, STR-2 and 3 conferred a protective effect against stroke in the presence of SHRSP alleles and STR-2 co-localized with the genes encoding for atrial natriuretic and brain natriuretic factors. Our investigation was designed to identify the genetic component responsible for large infarct volumes in the SHRSP in response to a focal ischaemic insult by performance of a genome scan in an F2 cross derived from the SHRSP and the normotensive reference strain, WKY rat. We identified a highly significant QTL on rat chromosome 5 with a lod score of 16.6 which accounts for 67% of the total variance, co-localizes with the genes encoding atrial and brain natriuretic factor and is blood pressure independent.

Topics: Animals; Atrial Natriuretic Factor; Blood Pressure; Brain Ischemia; Cerebral Arteries; Cerebrovascular Disorders; Chromosome Mapping; Crosses, Genetic; Disease Models, Animal; Female; Humans; Male; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Rats; Rats, Inbred SHR; Rats, Inbred WKY

In order to develop and validate an ovine model of myocardial infarction with subsequent impairement of left ventricular function, 15 instrumented sheep underwent selective microembolization of the left coronary arteries with 0.5 mL 90 microns polystyrene beads. Hemodynamics and plasma hormones were measured preembolization (baseline) and then at hours 2, 4, 6, and 12 and days 1, 2, 3, 5 and 7 postembolization. Of the 15 sheep studied, 2 (13%) died on the day of embolization from arrhythmias. In the remaining sheep, left ventricular systolic pressure and stroke work (both P < 0.001) were reduced promptly and remained below basal levels. Mean arterial pressure (P < 0.001) increased initially, then decreased to below basal levels by hour 6. Heart rate (P < 0.001) and left atrial pressure (P < 0.05) were increased while cardiac output was decreased (P < 0.05). Left ventricular ejection fraction at day 7 was reduced (38.8 +/- 3.5 vs 46.0 +/- 3.9% preembolization; P < 0.05). The cardiac enzymes creatine kinase (P < 0.001) and troponin-T (P < 0.001) were increased following microembolization and returned to basal levels by days 2 and 5 respectively. Plasma atrial and brain natriuretic peptides (both P < 0.001) and plasma renin activity (P < 0.005) were all increased following embolization. This ovine model mimics the hemodynamic and neurohumoral features of acute myocardial infarction, resulting in left ventricular dysfunction, and should prove suitable for the study of interventions in a number of these conditions.

Topics: Animals; Atrial Natriuretic Factor; Blood Pressure; Cardiac Output; Chronic Disease; Creatine Kinase; Disease Models, Animal; Female; Myocardial Infarction; Myocardium; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Renin; Sheep; Stroke Volume; Ventricular Dysfunction, Left

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

This study evaluated the role of changes in heart rate, cardiac filling pressures and cardiac tissue atrial and brain natriuretic peptides in the modulation of their plasma levels in a model of heart failure.. Atrial and brain natriuretic peptides constitute a dual natriuretic peptide system that regulates circulatory homeostasis.. The effects of 1) acute ventricular pacing, 2) acute volume expansion, and 3) volume expansion after 1 week of continuous pacing on plasma atrial and brain natriuretic peptide levels were compared in eight dogs. Atrial and ventricular tissue levels of the peptides were examined in 5 normal dogs (control group), 21 dogs paced for 1 week (group 1) and 10 dogs paced for 3 weeks (group 2).. Both acute pacing and volume expansion increased plasma atrial natriuretic peptide levels (from 53 +/- 41 to 263 +/- 143 pg/ml [mean +/- SD], p < 0.01, and from 38 +/- 23 to 405 +/- 221 pg/ml, p < 0.001, respectively). After 1 week, there was a marked increase in plasma levels of atrial natriuretic peptide, but the level did not increase further with volume expansion (from 535 +/- 144 to 448 +/- 140 pg/ml, p = 0.72). By contrast, plasma brain natriuretic peptide levels increased only modestly with acute pacing (from 12 +/- 4 to 20 +/- 8 pg/ml, p < 0.05) and after pacing for 1 week (from 13 +/- 4 to 48 +/- 20 pg/ml, p < 0.05) but did not change with acute or repeat volume expansion. In groups 1 and 2, atrial tissue levels of atrial natriuretic peptide (1.9 +/- 1.3 and 2.0 +/- 0.9 ng/mg, respectively) were lower than those in the control group (11.7 +/- 6.8 ng/mg, both p < 0.001), whereas ventricular levels were similar to those in the control group. Atrial tissue brain natriuretic peptide levels in groups 1 and 2 were similar to those in the control group. However, ventricular levels in group 2 (0.018 +/- 0.006 ng/mg) were increased compared with those in the control group (0.013 +/- 0.006 ng/mg, p < 0.05) and in group 1 (0.011 +/- 0.006 ng/mg, p < 0.05).. Atrial and brain natriuretic peptides respond differently to changes in heart rate and atrial pressures. Reduced atrial tissue atrial natriuretic peptide levels in heart failure may indicate reduced storage after enhanced cardiac release. However, the relatively modest change in cardiac tissue brain natriuretic peptide levels suggests that the elevated plasma levels may be mediated by mechanisms other than increased atrial pressures.

Topics: Acute Disease; Animals; Atrial Natriuretic Factor; Cardiac Pacing, Artificial; Chronic Disease; Dextrans; Disease Models, Animal; Dogs; Heart Failure; Hemodynamics; Myocardium; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Plasma Substitutes

The aortovenocaval fistular (AVF) rat represents a model of heart failure caused by increased cardiac volume overload and reduced renal function. Both circulating vasoconstrictors like the renin-angiotensin-aldosterone system and vasodilators like atrial and brain natriuretic peptides (ANP and BNP) are activated in this animal model of heart failure. In addition, neutral endopeptidase 24.11 (NEP) in plasma and urine is elevated in AVF rats. In the present investigation we examined the renal and hormonal effects of the NEP inhibitor, ecadotril, in acute and chronic studies in rats with an aortovenocaval fistula (AVF).. Sprague Dawley rats (350-430 g) were prepared by introducing a shunt between abdominal aorta and the vena cava.. Acute administration of the neutral endopeptidase inhibitor, ecadotril (30 mg/kg p.o.), significantly improved the reduced renal excretion of sodium in AVF rats (83 +/- 10 to 145 +/- 14 mumol/kg/h, P < 0.01) but had no significant effect in sham-operated rats. However, neutral endopeptidase activity in urine was significantly decreased after ecadotril in both groups. Plasma ANP was increased after ecadotril only in AVF rats (275 +/- 83 to 748 +/- 187 pg/ml, P < 0.05), whereas the increase in plasma BNP was not statistically significant. After 4 weeks of observation the ANP and BNP plasma levels, renin activity (PRA), angiotensin I, and neutral endopeptidase activity were significantly higher in AVF rats than in sham-operated rats. Four weeks on ecadotril (30 mg/kg p.o., b.i.d.) increased plasma ANP (245 +/- 48 as opposed to 450 +/- 77 pg/ml, P < 0.05) and decreased PRA (11.3 +/- 1.5 as opposed to 6.8 +/- 1.2 ng/ml/h, P < 0.005) in AVF rats. Plasma NEP activity was inhibited in both groups. Ventricle weight was significantly higher in AVF rats than in sham-operated controls, and ecadotril treatment over 4 weeks decreased ventricular hypertrophy to a slight extent.. These results indicate that in the AVF rat model of heart failure the neutral endopeptidase inhibitor, ecadotril, improves the reduced kidney function in AVF rats by raising natriuretic peptides in plasma and probably in urine. NEP inhibition with ecadotril could therefore offer useful therapeutic possibilities in the treatment of heart failure.

Topics: Angiotensin I; Animals; Aorta; Arteriovenous Fistula; Atrial Natriuretic Factor; Disease Models, Animal; Heart Failure; Natriuretic Peptide, Brain; Neprilysin; Nerve Tissue Proteins; Protease Inhibitors; Rats; Rats, Sprague-Dawley; Renin; Sodium; Thiorphan; Venae Cavae

The influence of neutral endopeptidase (NEP) inhibition with (S)-thiorphan on the hormonal, renal, and blood-pressure-lowering effects of an infusion of atrial (ANP), brain (BNP), and C-type natriuretic peptide (CNP) was evaluated in hypertensive transgenic rats (TGR) harboring an additional mouse renin gene (TGR(m(Ren2)27)). These TGR possess an activated natriuretic peptide system as compared with Sprague-Dawley rats (SDR), used in this study as control. (S)-Thiorphan significantly decreased blood pressure in anesthetized TGR but not in anesthetized SDR during the 60-min infusion period. Exogenously administered ANP decreased blood pressure in SDR with no significant effects in TGR after 60 min. In contrast, BNP infusion significantly decreased blood pressure in TGR, while changes in SDR were not significant. The blood pressure was further decreased after combined infusion of ANP and BNP with (S)-thiorphan in TGR. No effect on blood pressure was registered during infusion of CNP in either experimental group. The plasma levels of ANP, BNP, and cGMP were higher in TGR than in SDR, whereas plasma renin activity was lower. Co-administration of ANP, BNP, or CNP with the NEP inhibitor (S)-thiorphan potentiated the plasma ANP, BNP, and cGMP. Infusion of ANP alone did not affect BNP plasma levels of TGR and vice versa. In contrast, CNP infusion increased ANP plasma levels in both TGR and SDR. Renal excretion of sodium and cGMP increased after infusion of (S)-thiorphan and ANP or BNP in both TGR and SDR. The combination of ANP and (S)-thiorphan had a slightly greater effect on urinary excretion of sodium and cGMP in TGR than either compound alone, but the effects were more pronounced in SDR than in TGR. Finally, infusion of CNP alone and in combination with (S)-thiorphan influenced the excretion of sodium and cyclic GMP only slightly. These results indicate that inhibition of neutral endopeptidase by (S)-thiorphan potentiates the hemodynamic and renal effects of natriuretic peptides ANP and BNP, and to some extent those of CNP, in hypertensive TGR and normotensive SDR. In contrast to ANP and BNP, infusion of CNP had no effect on the blood pressure in anesthetized TGR or SDR. Inhibition of NEP therefore seems to be a promising way to potentiate endogenous levels of natriuretic peptides, which may be of therapeutic benefit in cardiovascular diseases such as hypertension or heart failure.

Topics: Animals; Animals, Genetically Modified; Atrial Natriuretic Factor; Blood Pressure; Cyclic GMP; Disease Models, Animal; Drug Therapy, Combination; Electrolytes; Hypertension; Mice; Natriuretic Peptide, Brain; Natriuretic Peptide, C-Type; Neprilysin; Protease Inhibitors; Proteins; Rats; Rats, Sprague-Dawley; Renin; Sodium; Thiorphan

Rapid ventricular pacing is widely accepted as a useful model to produce heart failure. The heart failure is associated with reduced myocardial energy stores and absence of cardiac hypertrophy. In this study, it was hypothesized that a modification of the protocol to intermittent pacing would permit time for partial recovery of myocardial energetics leading to improved cardiac function and development of hypertrophy. Eight dogs underwent conventional continuous right ventricular pacing to a biologic endpoint of severe heart failure (group 1). Another eight dogs underwent an intermittent pacing protocol over 7 weeks, consisting of 48-hour pacing alternating with 24-hour sinus rhythm (group 2) so as to produce the same total exposure to continuous pacing as in group 1. Six additional normal dogs were used as control animals for tissue metabolic data. Although both paced groups had similar directional changes in hemodynamic, neurohormonal, and echocardiographic variables, the absolute increases in pulmonary capillary wedge and right atrial pressures in group 2 (13 +/- 8 and 3 +/- 4 mmHg, respectively) were less marked than in group 1 (29 +/- 5 and 12 +/- 4 mmHg, respectively; both P = .002). Group 2 also had a more modest rise in plasma atrial natriuretic peptide and norepinephrine concentrations. There was no significant increase, however, in left ventricular mass in either group, and myocardial adenosine 5'-triphosphate levels were reduced to a similar extent compared to the control animals. Intermittent pacing produces a less advanced syndrome of heart failure than continuous pacing. Furthermore, the data suggest that reduced energy stores are not the predominant mechanism for impaired cardiac function, although they may contribute to the failure to hypertrophy in this model.

Topics: Animals; Atrial Function; Atrial Natriuretic Factor; Cardiac Pacing, Artificial; Disease Models, Animal; Dogs; Heart Failure; Hemodynamics; Hypertrophy, Left Ventricular; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Pulmonary Wedge Pressure; Time Factors

The objectives of this study were 1) to define in an experimental model of heart failure the time course of changes in plasma brain natriuretic peptide concentrations during the development of and recovery from heart failure, and 2) to relate the changes to changes in atrial natriuretic peptide concentration and hemodynamic status.. Brain natriuretic peptide is a circulating peptide with homology to atrial natriuretic peptide. However, unlike the latter, its changes during heart failure and its relation to cardiac filling pressures have not been studied.. Eight male mongrel dogs underwent right ventricular pacing at 250 beats/min for 3 weeks until heart failure occurred and were followed up during recovery for 4 weeks after cessation of pacing.. Heart failure was characterized by an increase in both left ventricular and end-diastolic pressure (6.6 +/- 4.1 mm Hg at the control measurements to 35.1 +/- 5.9 mm Hg at 3 weeks, p < 0.01) and right atrial pressure (6.7 +/- 1.1 to 11.4 +/- 2.1 mm Hg, p < 0.01). Recovery was accompanied by a return of cardiac filling pressures to control level. The time course of change of arterial plasma brain natriuretic peptide concentration was similar to that of atrial natriuretic peptide. Plasma concentrations of both peptides increased after 1 week of pacing (16 +/- 4 pg/ml at the control measurement to 59 +/- 20 pg/ml at 1 week, p < 0.001 for brain natriuretic peptide and 84 +/- 55 to 856 +/- 295 pg/ml, p < 0.001 for atrial natriuretic peptide). The level of both peptides then stayed level with no further increase at 3 weeks and returned to the control value by 4 weeks of recovery. There was an excellent correlation between plasma concentrations of the two peptides (r = 0.86, p < 0.001) and between the two peptides and cardiac filling pressures. However, compared with atrial natriuretic peptide, plasma brain natriuretic peptide concentration had a smaller percent increase during evolving heart failure and a slower rate of decline at recovery.. Brain and atrial natriuretic peptide constitute a dual natriuretic system and are both responsive to changes in cardiac filling pressures in heart failure. However, brain natriuretic peptide appears to be less responsive than atrial natriuretic peptide.

Topics: Analysis of Variance; Animals; Atrial Natriuretic Factor; Disease Models, Animal; Dogs; Heart Failure; Hemodynamics; Male; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Norepinephrine; Regression Analysis; Renin; Time Factors

The hemodynamic and renal effects of brain natriuretic peptide (BNP) were studied in conscious rats with experimental congestive heart failure (CHF) produced by an aortocaval fistula. The peptide had potent hypotensive, diuretic, and natriuretic effects in control rats, all of which were abolished in CHF. Plasma levels of BNP increased time-dependently during the development of CHF, and were more than four-fold higher in sodium retaining rats than in control rats. The data suggest that BNP secretion from the atria is increased in CHF, and that resistance to BNP, in addition to the relative resistance to atrial natriuretic factor, may contribute to sodium retention in CHF.

Topics: Animals; Atrial Natriuretic Factor; Brain Chemistry; Disease Models, Animal; Heart Failure; Hemodynamics; Kidney Function Tests; Natriuresis; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Peptides; Radioimmunoassay; Rats; Rats, Inbred WKY