cyclic-gmp and Ventricular-Dysfunction--Left

Coronary artery disease is a major underlying etiology for heart failure. The role of coronary microvascular disease, and endothelial dysfunction, in the pathophysiology of heart failure is poorly appreciated. Endothelial dysfunction, induced by oxidative stress, contributes to the development of heart failure. Alterations of endothelial function and nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway are involved in the pathophysiology of heart failure with both reduced and preserved ejection fraction. Indeed, an altered endothelium dependent vasodilatation, causing repeated episodes of ischemia/reperfusion, can induce a chronic stunned myocardium with systolic dysfunction and an increased diastolic stiffness with diastolic dysfunction. Moreover, the altered NO-cGMP pathway directly affects myocardial homeostasis. Endothelial dysfunction is associated with worse prognosis and higher rate of cardiovascular events. Potential therapeutic strategies targeting the NO-cGMP pathway in patients with HF will be discussed in this review article. Although clinical data are still inconclusive, the NO-cGMP pathway represents a promising target for therapy.

Topics: Cyclic GMP; Endothelium, Vascular; Heart Failure; Humans; Microcirculation; Muscle, Skeletal; Myocardium; Nitric Oxide; Prognosis; Signal Transduction; Ventricular Dysfunction, Left

Group II pulmonary hypertension (PH) commonly occurs in the setting of a pressure-overloaded left ventricle (LV) which is also conducive to the development of heart failure with preserved ejection fraction. Population trends and a high prevalence of underlying causative conditions, such as essential hypertension or aortic stenosis, have increased the awareness of the pressure-overloaded LV and associated group II pulmonary hypertension. Patients often exhibit poor exercise tolerance and signs of heart failure indistinguishable from systolic heart failure; but effective medical treatments in this area have been lacking. Recent preclinical work has shed light on how the down-regulated nitric oxide - cyclic GMP pathway (within the myocardium and pulmonary vasculature) contributes to the pathophysiology of these associated conditions. This article will discuss the impact of the nitric oxide - cyclic GMP pathway on the pathogenesis of the pressure-overloaded LV and group II pulmonary hypertension, and will also introduce the potential therapeutic value of modulating this pathway.

Topics: Antihypertensive Agents; Aortic Valve Stenosis; Cardiomyopathies; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 5; Diastole; Heart Failure; Humans; Hypertension, Pulmonary; Hypertrophy, Left Ventricular; Nitric Oxide; Oxidative Stress; Phosphodiesterase 5 Inhibitors; Signal Transduction; Stroke Volume; Systole; Ventricular Dysfunction, Left; Ventricular Remodeling

Diabetes mellitus (DM) is highly prevalent and is an important risk factor for congestive heart failure (HF). Increased left ventricular (LV) diastolic stiffness is recognized as the earliest manifestation of DM-induced LV dysfunction, but its pathophysiology remains incompletely understood. Mechanisms whereby DM increases LV diastolic stiffness differ between HF with normal LV ejection fraction (EF) (HFNEF) and HF with reduced LVEF (HFREF). In diabetic HFREF, fibrosis and deposition of advanced glycation end products (AGEs) are the most important contributors to high LV diastolic stiffness, whereas in diabetic HFNEF, elevated resting tension of hypertrophied cardiomyocytes is the most important contributor to high LV diastolic stiffness. As HF mortality remains high in DM despite proven efficacy of current treatments, better understanding of the pathophysiology of high LV diastolic stiffness could be beneficial for novel therapeutic strategies.

Topics: Cyclic GMP; Diabetic Angiopathies; Diastole; Extracellular Matrix; Glycation End Products, Advanced; Heart; Heart Failure, Diastolic; Humans; Incidence; Inflammation; Myocardium; Nitric Oxide; Oxidative Stress; Ventricular Dysfunction, Left

Inhalation of nitric oxide (iNO) during myocardial ischaemia and after reperfusion confers cardioprotection in preclinical studies via enhanced cyclic guanosine monophosphate (cGMP) signalling. We tested whether iNO reduces reperfusion injury in patients with ST-elevation myocardial infarction (STEMI; NCT01398384).. We randomized in a double-blind, placebo-controlled study 250 STEMI patients to inhale oxygen with (iNO) or without (CON) 80 parts-per-million NO for 4 h following percutaneous revascularization. Primary efficacy endpoint was infarct size as a fraction of left ventricular (LV) size (IS/LVmass), assessed by delayed enhancement contrast magnetic resonance imaging (MRI). Pre-specified subgroup analysis included thrombolysis-in-myocardial-infarction flow in the infarct-related artery, troponin T levels on admission, duration of symptoms, location of culprit lesion, and intra-arterial nitroglycerine (NTG) use. Secondary efficacy endpoints included IS relative to risk area (IS/AAR), myocardial salvage index, LV functional recovery, and clinical events at 4 and 12 months. In the overall population, IS/LVmass at 48-72 h was 18.0 ± 13.4% in iNO (n = 109) and 19.4 ± 15.4% in CON [n = 116, effect size -1.524%, 95% confidence interval (95% CI) -5.28, 2.24; P = 0.427]. Subgroup analysis indicated consistency across clinical confounders of IS but significant treatment interaction with NTG (P = 0.0093) resulting in smaller IS/LVmass after iNO in NTG-naïve patients (n = 140, P < 0.05). The secondary endpoint IS/AAR was 53 ± 26% with iNO vs. 60 ± 26% in CON (effect size -6.8%, 95% CI -14.8, 1.3, P = 0.09) corresponding to a myocardial salvage index of 47 ± 26% vs. 40 ± 26%, respectively, P = 0.09. Cine-MRI showed similar LV volumes at 48-72 h, with a tendency towards smaller increases in end-systolic and end-diastolic volumes at 4 months in iNO (P = 0.048 and P = 0.06, respectively, n = 197). Inhalation of nitric oxide was safe and significantly increased cGMP plasma levels during 4 h reperfusion. The Kaplan-Meier analysis for the composite of death, recurrent ischaemia, stroke, or rehospitalizations showed a tendency toward lower event rates with iNO at 4 months and 1 year (log-rank test P = 0.10 and P = 0.06, respectively).. Inhalation of NO at 80 ppm for 4 h in STEMI was safe but did not reduce infarct size relative to absolute LVmass at 48-72h. The observed functional recovery and clinical event rates at follow-up and possible interaction with nitroglycerine warrant further studies of iNO in STEMI.

Topics: Administration, Inhalation; Aged; Cyclic GMP; Double-Blind Method; Female; Free Radical Scavengers; Heart Ventricles; Humans; Kaplan-Meier Estimate; Magnetic Resonance Imaging, Cine; Male; Middle Aged; Mortality; Myocardial Reperfusion Injury; Nitric Oxide; Nitroglycerin; Organ Size; Oxygen Inhalation Therapy; Patient Readmission; Recurrence; ST Elevation Myocardial Infarction; Stroke; Vasodilator Agents; Ventricular Dysfunction, Left

Left ventricular hypertrophy and diastolic dysfunction (LVDD) remain highly frequent markers of cardiac damage and risk of progression to symptomatic heart failure, especially in resistant hypertension (RHTN). We have previously demonstrated that administration of sildenafil in hypertensive rats improves LVDD, restoring phosphodiesterase type 5 (PDE-5) inhibition in cardiac myocytes.. We hypothesized that the long-acting PDE-5 inhibitor tadalafil may be clinically useful in improving LVDD in RHTN independently of blood pressure (BP) reduction. A single blinded, placebo-controlled, crossover study enrolled 19 patients with both RHTN and LVDD. Firstly, subjects received tadalafil (20 mg) for 14 days and after a 2-week washout period, they received placebo orally for 14 days. Patients were evaluated by office BP and ambulatory BP monitoring (ABPM), endothelial function (FMD), echocardiography, plasma brain natriuretic peptide (BNP-32), cyclic guanosine monophosphate (cGMP) and nitrite levels.. No significant differences were detected in BP measurements. Remarkably, at least four echocardiographic parameters related with diastolic function improved accompanied by decrease in BNP-32 in tadalafil use. Although increasing cGMP, tadalafil did not change endothelial function or nitrites. There were no changes in those parameters after placebo.. The current findings suggest that tadalafil improves LV relaxation through direct effects PDE-5-mediated in the cardiomyocytes with potential benefit as an adjunct to treat symptomatic subjects with LVDD such as RHTN patients.

Topics: Aged; Blood Pressure; Carbolines; Cross-Over Studies; Cyclic GMP; Diastole; Drug Resistance; Female; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Middle Aged; Natriuretic Peptide, Brain; Nitrites; Phosphodiesterase 5 Inhibitors; Single-Blind Method; Tadalafil; Ventricular Dysfunction, Left; Ventricular Function, Left

Brain natriuretic peptide (BNP) is increased in left ventricular impairment and neutral endopeptidase (NEP) is involved in its metabolism. In random order, eight patients with left ventricular impairment received placebo, a 4-h infusion of human BNP (3.0 pmol/kg min), a single oral dose of NEP inhibitor (SCH 42495, 300 mg), and combined BNP and SCH 42495. Plasma BNP, cGMP, and cortisol were significantly increased by all three treatments (P < 0.05-P < 0.001). Combined treatment had a synergistic effect on plasma cGMP. The metabolic clearance rate of exogenous BNP was reduced (25%) by NEP inhibition. Endogenous plasma ANP was augmented more than BNP by NEP inhibition. Plasma aldosterone, unchanged during infusions, rose markedly after BNP and after the combined treatment (P < 0.05 for both). Urine sodium excretion, increased by NEP inhibition (P < 0.05) and by BNP (P = 0.05), was unchanged during combined treatment. Urine cGMP excretion was increased, whereas blood pressure was reduced by all active treatments (P < 0.05-0.01 for all). Heart rate increased only with combined treatment (P = 0.007). Plasma renin activity, norepinephrine, and cardiac output were unaffected. BNP infusion and NEP inhibition both induced significant hemodynamic and renal responses. The augmented hypotensive effect of combined treatments, and consequent fall in renal perfusion pressure, may underly the observed blunting of the natriuretic response that occurred despite greater than additive increments in plasma BNP, ANP, and cGMP.

Topics: Adult; Aged; Aldosterone; Blood Pressure; Cyclic GMP; Drug Synergism; Humans; Male; Metabolic Clearance Rate; Methionine; Middle Aged; Natriuresis; Natriuretic Peptide, Brain; Neprilysin; Protease Inhibitors; Renin; Ventricular Dysfunction, Left

The effects of recombinant alpha-human atrial natriuretic peptide (alpha-hANP) infusion an acute left ventricular dysfunction provoked by exercise were examined in 14 men with coronary artery disease. Patients performed symptom-limited, graded exercise on a supine bicycle ergometer. Plasma alpha-hANP and guanosine 3',5'-monophosphate (cyclic GMP) concentrations as well as hemodynamic variables were measured at rest, during and after exercise. In 14 patients whose pulmonary artery wedge pressure was > 20 mm Hg at peak exercise, the same exercise protocol was repeated at 30 minutes after starting intravenous alpha-hANP infusion (0.05 microgram.kg-1.min-1). In 8 of these patients, a Webster thermodilution catheter was advanced into the coronary sinus for measurement of coronary sinus blood flow. From the control exercise test, plasma alpha-hANP concentration increased from 86 +/- 20 pg/ml at rest to 188 +/- 32 pg/ml at peak exercise (p < 0.001), and plasma cyclic GMP concentration increased from 4.8 +/- 1.9 pmol/ml at rest to 7.2 +/- 2.9 pmol/ml at peak exercise (p < 0.001). Both plasma alpha-hANP and cyclic GMP concentrations showed a significant positive correlation with pulmonary artery wedge pressure during control exercise. With alpha-hANP infusion, systolic and diastolic pulmonary artery pressures and pulmonary artery wedge pressure were significantly decreased at all time points during exercise testing. Heart rate was increased and systolic blood pressure was significantly decreased at rest and at 3 minutes of exercise. Diastolic blood pressure, systemic vascular resistance, and pulmonary vascular resistance were significantly decreased at rest.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aged; Atrial Natriuretic Factor; Coronary Circulation; Coronary Disease; Cyclic GMP; Exercise Test; Hemodynamics; Humans; Male; Middle Aged; Ventricular Dysfunction, Left

In man, chronic antihypertensive calcium antagonist treatment improves cardiac function and reduces plasma ANF concentrations. Physical exercise increases cardiac workload and plasma ANF levels. In the present study, we investigated the effects of acute administration of the dihydropyridine calcium antagonist BAY t 7207 (BAY) during bicycle exercise on plasma ANF and plasma cyclic GMP levels, on mean arterial pressure (MAP), heart rate (HR), and on natriuresis and urinary urodilatin excretion. In a randomized, double-blind placebo controlled cross-over trial, 8 patients (age 56.8 +/- 2.5 y) with documented coronary artery disease and mildly impaired left ventricular function (EF 50.0 +/- 1.3%), received oral BAY (20 mg) or placebo. Forty-five minutes after medication, patients underwent a standardised exercise bicycle test in the supine position (6 min 25 W, 6 min 50 W). Before exercise, MAP was lower after BAY (88.8 +/- 4.1 mmHg) than after placebo (95.7 +/- 3.5 mmHg; p = 0.024), and HR was higher after BAY (76.8 +/- 3.5 bpm) than after placebo (69.5 +/- 3.6 bpm; p = 0.049). Plasma ANF tended to be higher after BAY (31.2 +/- 5.6 pg/ml) than after placebo (26.7 +/- 5.0 pg/ml), and plasma cGMP was not different (BAY 3.4 +/- 0.3, placebo 3.8 +/- 0.3 pmol/ml). During exercise, the relative increases in HR (+43%) and MAP (+17%) were identical after BAY and placebo. In contrast, ANF levels during exercise increased by 130 +/- 28% after placebo but only by 36 +/- 11% after BAY (p = 0.011). In parallel, plasma cyclic GMP increased by 61 +/- 13% after placebo and by 20 +/- 8% after BAY (p = 0.013). At the end of exercise, the BAY-induced reduction in plasma cyclic GMP reflected the reduction in diastolic arterial pressure (r = 0.717; p = 0.045). Compared to placebo, BAY treatment increased the fractional excretion rate of sodium from 0.46 +/- 0.11 to 0.90 +/- 0.22% (p = 0.016), without relation to urinary urodilatin excretion. Thus, the calcium antagonist BAY t 7207 attenuated the exercise-induced increase in plasma ANF and cyclic GMP probably due to its vasodilator effect. The relationship between blood pressure and the ANF system during exercise, which parallels findings during chronic antihypertensive treatment, may open a perspective for early evaluation of long-term therapy with calcium channel blockers.

Topics: Atrial Natriuretic Factor; Calcium Channel Blockers; Cross-Over Studies; Cyclic GMP; Diuretics; Double-Blind Method; Exercise Test; Humans; Male; Middle Aged; Peptide Fragments; Supine Position; Ventricular Dysfunction, Left

Topics: Cyclic GMP; Guanosine Monophosphate; Heart Failure; Heterocyclic Compounds, 2-Ring; Humans; Pyrimidines; Stroke Volume; Ventricular Dysfunction, Left

Titin phosphorylation contributes to left ventricular (LV) diastolic dysfunction. The independent effects of inflammation on the molecular pathways that regulate titin phosphorylation are unclear.. We investigated the effects of collagen-induced inflammation and subsequent tumor necrosis factor-α (TNF-α) inhibition on mRNA expression of genes involved in regulating titin phosphorylation in 70 Sprague-Dawley rats. LV diastolic function was assessed with echocardiography. Circulating inflammatory markers were quantified by enzyme-linked immunosorbent assay and relative LV gene expression was assessed by Taqman® polymerase chain reaction. Differences in normally distributed variables between the groups were determined by two-way analysis of variance (ANOVA), followed by Tukey post-hoc tests. For non-normally distributed variables, group differences were determined by Kruskal-Wallis tests.. Collagen inoculation increased LV relative mRNA expression of vascular cell adhesion molecule 1 (VCAM1), pentraxin 3 (PTX3), and inducible nitric oxide synthase (iNOS) compared to controls, indicating local microvascular inflammation. Collagen inoculation decreased soluble guanylate cyclase alpha-2 (sGCα2) and soluble guanylate cyclase beta-2 (sGCβ2) expression, suggesting downregulation of nitric oxide-soluble guanylate cyclase-cyclic guanosine monophosphate (NO-sGC-cGMP) signaling. Inhibiting TNF-α prevented collagen-induced changes in VCAM1, iNOS, sGCα2 and sGCβ2 expression. Collagen inoculation increased protein phosphatase 5 (PP5) expression. Like LV diastolic dysfunction, increased PP5 expression was not prevented by TNF-α inhibition.. Inflammation-induced LV diastolic dysfunction may be mediated by a TNF-α-independent increase in PP5 expression and dephosphorylation of the N2-Bus stretch element of titin, rather than by TNF-α-induced downregulation of NO-sGC-cGMP pathway-dependent titin phosphorylation. The steady rise in number of patients with inflammation-induced diastolic dysfunction, coupled with low success rates of current therapies warrants a better understanding of the systemic signals and molecular pathways responsible for decreased titin phosphorylation in development of LV diastolic dysfunction. The therapeutic potential of inhibiting PP5 upregulation in LV diastolic dysfunction requires investigation.

Topics: Animals; Collagen; Cyclic GMP; Inflammation; Rats; Rats, Sprague-Dawley; RNA, Messenger; Soluble Guanylyl Cyclase; Tumor Necrosis Factor-alpha; Ventricular Dysfunction, Left

Human atrial natriuretic peptide (hANP) and spontaneous nitric oxide (NO) donor share cyclic guanosine monophosphate (cGMP) as a second messenger, but their effect on myocardium may differ. We compared the effect of hANP and sodium nitroprusside (SNP) on left ventricular (LV) mechano-energetics in heart failure (HF).. Ten patients with HF due to previous myocardial infarction (LV ejection fraction: 45±3%) were instrumented with conductance and coronary sinus thermodilution catheters. LV contractility (Ees: slope of end-systolic pressure-volume relation) and the ratio of LV stroke work (SW) to myocardial oxygen consumption (SW/MVO2=mechanical efficiency) were measured in response to intravenous infusion of ANP (0.05 μg/kg/min) or SNP (0.3 μg/kg/min) to lower blood pressure by at least 10 mmHg, and changes in plasma cGMP.. SNP had no effect on Ees, SW, or MVO2, thus SW/MVO2 remained unchanged (40.54±5.84% to 36.59±5.72%, p=0.25). ANP increased Ees, and decreased MVO2 with preserved SW, resulting in improved SW/MVO2 (40.49±6.35% to 50.30±7.96%, p=0.0073). Infusion of ANP (10.42-34.95 pmol/ml, p=0.0003) increased cGMP levels, whereas infusion of SNP had no effect (10.42-12.23 pmol/ml, p=0.75).. Compared to SNP, the ANP-dependent increase in cGMP may ameliorate myocardial inotropy and energetics in HF.

Topics: Atrial Natriuretic Factor; Blood Pressure; Cyclic GMP; Heart Failure; Humans; Infusions, Intravenous; Myocardial Contraction; Myocardial Infarction; Myocardium; Nitric Oxide Donors; Nitroprusside; Oxygen Consumption; Stroke Volume; Vasodilator Agents; Ventricular Dysfunction, Left

Nitric oxide (NO) bioavailability is reduced in the setting of heart failure. Nitrite (NO2) is a critically important NO intermediate that is metabolized to NO during pathological states. We have previously demonstrated that sodium nitrite ameliorates acute myocardial ischemia/reperfusion injury.. No evidence exists as to whether increasing NO bioavailability via nitrite therapy attenuates heart failure severity after pressure-overload-induced hypertrophy.. Serum from patients with heart failure exhibited significantly decreased nitrosothiol and cGMP levels. Transverse aortic constriction was performed in mice at 10 to 12 weeks. Sodium nitrite (50 mg/L) or saline vehicle was administered daily in the drinking water postoperative from day 1 for 9 weeks. Echocardiography was performed at baseline and at 1, 3, 6, and 9 weeks after transverse aortic constriction to assess left ventricular dimensions and ejection fraction. We observed increased cardiac nitrite, nitrosothiol, and cGMP levels in mice treated with nitrite. Sodium nitrite preserved left ventricular ejection fraction and improved left ventricular dimensions at 9 weeks (P<0.001 versus vehicle). In addition, circulating and cardiac brain natriuretic peptide levels were attenuated in mice receiving nitrite (P<0.05 versus vehicle). Western blot analyses revealed upregulation of Akt-endothelial nitric oxide-nitric oxide-cGMP-GS3Kβ signaling early in the progression of hypertrophy and heart failure.. These results support the emerging concept that nitrite therapy may be a viable clinical option for increasing NO levels and may have a practical clinical use in the treatment of heart failure.

Topics: Aged; Animals; Biological Availability; Cyclic GMP; Cytoprotection; Disease Models, Animal; Female; Heart Failure; Hemodynamics; Humans; Male; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; Middle Aged; Nitric Oxide; Signal Transduction; Sodium Nitrite; Stroke Volume; Ventricular Dysfunction, Left

Obesity and Type 2 diabetes mellitus (DM) induce left ventricular (LV) diastolic dysfunction, which contributes to an increasing prevalence of heart failure with a preserved LV ejection fraction. We investigated the effects of sitagliptin (SITA), an inhibitor of dipeptidylpeptidase-4 (DPP-4) and anti-diabetic drug, on LV structure and function of obese mice with Type 2 DM.. Obese Type 2 diabetic mice (Lepr(db/db), BKS.Cg-Dock7(m)+/+ Lepr(db)/J), displaying increased cardiomyocyte and LV stiffness at the age of 16 weeks, were treated with SITA (300 mg/kg/day) or vehicle for 8 weeks. SITA severely impaired serum DPP-4 activity, but had no effect on glycaemia. Invasive haemodynamic recordings showed that SITA reduced LV passive stiffness and increased LV stroke volume; LV end-systolic elastance remained unchanged. In addition, SITA reduced resting tension of isolated single cardiomyocytes and intensified phosphorylation of the sarcomeric protein titin. SITA also increased LV concentrations of cGMP and increased activity of protein kinase G (PKG). In vitro activation of PKG decreased resting tension of cardiomyocytes from vehicle-treated mice, but had no effect on resting tension of cardiomyocytes from SITA-treated mice.. In obese Type 2 diabetic mice, in the absence of hypoglycaemic effects, inhibition of DPP-4 decreases LV passive stiffness and improves global LV performance. These effects seem at least partially mediated by stimulatory effects on the myocardial cGMP-PKG pathway and, hence, on the phosphorylation status of titin and the hereto coupled cardiomyocyte stiffness modulus.

Topics: Animals; Atrial Natriuretic Factor; Compliance; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Diabetes Mellitus, Experimental; Diastole; Dipeptidyl-Peptidase IV Inhibitors; Drug Evaluation, Preclinical; Heart; Heart Ventricles; Male; Mice; Myocytes, Cardiac; Pyrazines; Random Allocation; Sitagliptin Phosphate; Triazoles; Ventricular Dysfunction, Left

It is not clear yet how tadalafil affects nonischemic cardiomyopathy, although its beneficial effects on acute myocardial infarction are well-known. We investigated tadalafil's beneficial effects on nonischemic cardiomyopathy and the specific mechanisms of its effects.. Cardiomyopathy was induced in mice by a single intraperitoneal injection of doxorubicin (15 mg/kg). In some cases, tadalafil (4 mg/kg/day, p.o., 14 days) was started simultaneously. After two weeks, cardiac function was evaluated by echocardiography and cardiac catheterization, then all of the mice were killed and cardiac specimens were subjected for hemotoxylin and eosin staining, Masson's trichrome staining, terminal deoxynucleotidyltransferase dUTP nick-end labeling assay, enzyme-linked immunosorbent assay, and Western blot.. Two weeks later, left ventricular dilatation and dysfunction were apparent in mice given doxorubicin but were significantly attenuated by tadalafil treatment. Tadalafil also protected hearts against doxorubicin-induced cardiomyocyte atrophy/degeneration and myocardial fibrosis. No doxorubicin-induced apoptotic effects were seen between groups. Cardiac cGMP level was lower in the doxorubicin-treated group, however it was significantly increased with tadalafil treatment. Compared to the control group, the myocardial expression of 3 sarcomeric proteins, myosin heavy chain, troponin I, and desmin were significantly decreased in the doxorubicin-treated group, which were restored by the tadalafil treatment.. The present study indicates a protective effect of tadalafil mainly through cGMP signaling pathway against doxorubicin-induced nonischemic cardiomyopathy.

Topics: Animals; Antibiotics, Antineoplastic; Atrophy; Carbolines; Cardiomyopathies; Cardiotonic Agents; Cyclic GMP; Disease Models, Animal; Doxorubicin; Fibrosis; Male; Mice; Mice, Inbred C57BL; Myocardium; Myocytes, Cardiac; Phosphodiesterase 5 Inhibitors; Signal Transduction; Tadalafil; Ventricular Dysfunction, Left

Little is known about the vascular function and expression of endothelial and neuronal nitric oxide synthases (eNOS and nNOS) in Duchenne muscular dystrophy (DMD). Bradykinin is involved in the regulation of eNOS expression induced by angiotensin-converting enzyme inhibitors. We characterized the vascular function and eNOS and nNOS expression in a canine model of DMD and evaluated the effects of chronic bradykinin treatment. Vascular function was examined in conscious golden retriever muscular dystrophy (GRMD) dogs with left ventricular dysfunction (measured by echocardiography) and in isolated coronary arteries. eNOS and nNOS proteins in carotid arteries were measured by western blot and cyclic guanosine monophosphate (cGMP) content was analyzed by radioimmunoassay. Compared with controls, GRMD dogs had an impaired vasodilator response to acetylcholine. In isolated coronary artery, acetylcholine-elicited relaxation was nearly absent in placebo-treated GRMD dogs. This was explained by reduced nNOS and eNOS proteins and cGMP content in arterial tissues. Chronic bradykinin infusion (1 μg/min, 4 weeks) restored in vivo and in vitro vascular response to acetylcholine to the level of control dogs. This effect was NO-mediated through upregulation of eNOS and nNOS expression. In conclusion, this study is the first to demonstrate that DMD is associated with NO-mediated vascular endothelial dysfunction linked to an altered expression of eNOS and nNOS, which can be overcome by bradykinin.

Topics: Animals; Blood Pressure; Bradykinin; Carotid Arteries; Cyclic GMP; Disease Models, Animal; Dogs; Endothelium, Vascular; Muscular Dystrophy, Duchenne; Nitric Oxide; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type III; Ventricular Dysfunction, Left

We previously showed that treatment with tadalafil, a long-acting phosphodiesterase-5a (PDE5a) inhibitor, effectively prevented adverse left ventricular (LV) remodeling of the infarcted heart. We hypothesized that short-hairpin RNA (shRNA) therapy targeting PDE5a would simulate the effects of pharmacological intervention for treatment of postinfarction LV remodeling and dysfunction. Experimental model of myocardial infarction was developed in female mice by permanent ligation of left coronary artery. Immediately after that, an adenoviral vector encoding for shRNA sequence targeting PDE5a (Ad-shPDE5a) was injected intramyocardially, which specifically inhibited PDE5a in the heart. Four weeks later, Ad-shPDE5a treated mice showed significant mitigation of the left ventricle (LV) dilatation and dysfunction as indicated by smaller LV cavity and more preserved ejection fraction and fractional shortening. Infarction size and fibrosis were significantly reduced in Ad-shPDE5a-treated mice. Additionally, more salvaged cardiomyocytes, significantly reduced collagen contents, and higher blood vessel density were observed in Ad-shPDE5a-treated mice. The cytoprotective effects of Ad-shPDE5a were demonstrated in vitro in Ad-shPDE5a transfected cardiomyocytes cultured under oxygen glucose deprivation. Among downstream mediators of PDE5a signaling, cyclic GMP (cGMP) and cGMP-dependent protein kinase G (PKG) were activated with concomitant reduction in caspase-3 activity. However, no significant change in PKA and cAMP activities were observed in Ad-shPDE5a-treated hearts. Inhibition with shRNA improved cardiac remodeling and dysfunction by reducing infarction size and cardiac fibrosis and increased cGMP and PKG activity. These findings suggest that PDE5 inhibition with Ad-shPDE5a is a novel approach for treatment of myocardial infarction.

Topics: Adenoviridae; Animals; Cells, Cultured; Coronary Vessels; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Cyclic Nucleotide Phosphodiesterases, Type 5; Female; Ligation; Male; Mice; Mice, Inbred C57BL; Models, Animal; Myocardial Infarction; Myocytes, Cardiac; RNA, Small Interfering; RNA, Viral; Transfection; Ventricular Dysfunction, Left; Ventricular Remodeling

Pulmonary hypertension (PH) in left ventricular dysfunction is attributable not only to backward failure of the left ventricle, but also to increased pulmonary vascular resistance (PVR) in some patients. Recently, Rho-kinase has been known as a potent growth stimulator and mediator of vasoconstriction, and Rho-kinase inhibitors could ameliorate PVR, little is known about the role of Rho-kinase in left ventricular dysfunction-induced PH. We utilized the ascending aortic-banded rat and assessed the effect of Rho-kinase inhibitor fasudil on the development of PH secondary to left ventricular dysfunction. Subsequently, in rats subjected to aortic banding for 6 weeks, there were increases in mean pulmonary arterial pressure, pulmonary arteriolar medial thickness, active RhoA, Rho-kinase II, Rho-kinase activity, endothelial nitric oxide synthase (eNOS) and endothelin-1(ET-1) concomitant with decreased levels in NO and cGMP in the lung. Treatment with fasudil at a dose of 30 mg/kg/day from days 1 to 28 or from days 29 to 42 decreased the mean pulmonary arterial pressure by 57% and 56%, right ventricular hypertrophy by 31% and 30%, pulmonary arteriolar medial thickness by 50% and 50%, and pulmonary expression of Rho-kinase II by 41% and 28%, respectively, as well as augmented pulmonary expression of eNOS by 16% and 31% and NO by 50% and 76%, respectively, when compared with the vehicle controls. In conclusion, these results suggest that inhibition of Rho-kinase may provide therapeutic potential for preventing and attenuating the development of PH in left ventricular dysfunction. Further translational study in human is needed to substantiate the findings.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Arterioles; Cyclic GMP; Endothelin-1; Hypertension, Pulmonary; Lung; Male; Nitric Oxide; Nitric Oxide Synthase Type III; Protein Kinase Inhibitors; Pulmonary Artery; Rats; Rats, Wistar; rho-Associated Kinases; Treatment Outcome; Ventricular Dysfunction, Left

Omega-3 polyunsaturated fatty acids (eicosapentaenoic acid and docosahexaenoic acid) from fish oil ameliorate cardiovascular diseases. However, little is known about the effects of ω-3 polyunsaturated fatty acids on cardiac fibrosis, a major cause of diastolic dysfunction and heart failure. The present study assessed the effects of ω-3 polyunsaturated fatty acids on cardiac fibrosis.. We assessed left ventricular fibrosis and pathology in mice subjected to transverse aortic constriction after the consumption of a fish oil or a control diet. In control mice, 4 weeks of transverse aortic constriction induced significant cardiac dysfunction, cardiac fibrosis, and cardiac fibroblast activation (proliferation and transformation into myofibroblasts). Dietary supplementation with fish oil prevented transverse aortic constriction-induced cardiac dysfunction and cardiac fibrosis and blocked cardiac fibroblast activation. In heart tissue, transverse aortic constriction increased active transforming growth factor-β1 levels and phosphorylation of Smad2. In isolated adult mouse cardiac fibroblasts, transforming growth factor-β1 induced cardiac fibroblast transformation, proliferation, and collagen synthesis. Eicosapentaenoic acid and docosahexaenoic acid increased cyclic GMP levels and blocked cardiac fibroblast transformation, proliferation, and collagen synthesis. Eicosapentaenoic acid and docosahexaenoic acid blocked phospho-Smad2/3 nuclear translocation. DT3, a protein kinase G inhibitor, blocked the antifibrotic effects of eicosapentaenoic acid and docosahexaenoic acid. Eicosapentaenoic acid and docosahexaenoic acid increased phosphorylated endothelial nitric oxide synthase and endothelial nitric oxide synthase protein levels and nitric oxide production.. Omega-3 fatty acids prevent cardiac fibrosis and cardiac dysfunction by blocking transforming growth factor-β1-induced phospho-Smad2/3 nuclear translocation through activation of the cyclic GMP/protein kinase G pathway in cardiac fibroblasts.

Topics: Animals; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Dietary Supplements; Fatty Acids, Omega-3; Fibroblasts; Fibrosis; Heart Ventricles; Male; Mice; Mice, Inbred C57BL; Nitric Oxide; Nitric Oxide Synthase Type III; Signal Transduction; Smad2 Protein; Smad3 Protein; Transforming Growth Factor beta1; Up-Regulation; Ventricular Dysfunction, Left; Ventricular Remodeling; Vitamin E

Statins have pleiotropic effects that can reverse endothelial dysfunction and prevent the development of left ventricular hypertrophy (LVH). The goal of this study was to assess the effect of treatment with atorvastatin on the endothelial dysfunction of epicardial coronary arteries and the development of LVH in a porcine model. LVH was induced through 2 months of aortic banding (AB) of the ascending aorta. Experimental groups were (1) sham untreated: without AB, (2) LVH untreated: with AB, and (3,4) LVH treated: with AB treated with 40 and 80 mg of atorvastatin, respectively, for 60 days, and (5) sham treated: without AB treated with 80 mg of atorvastatin for 60 days. Vascular reactivity studies were performed in organ chambers experiments. NO bioavailability was assessed using cyclic guanosine monophosphate quantification. Oxidative stress levels were measured by quantifying angiotensin II) and nitrite/nitrate levels. LVH and LV diastolic function were evaluated using echocardiography. Atorvastatin decreased endothelium-dependent relaxations and cyclic guanosine monophosphate levels in all treated animals. Angiotensin II levels were increased, whereas nitrite levels were similar among groups (P > 0.05). LV diastolic dysfunction and LVH were significantly greater in all treated animals (P < 0.01). High-density lipoprotein levels and low-density lipoprotein levels were significantly decreased in animals receiving atorvastatin (P < 0.05). In this swine model of LVH, atorvastatin did not prevent LVH development or coronary endothelial dysfunction and resulted in worsening of the LV diastolic dysfunction.

Topics: Angiotensin II; Animals; Aorta; Atorvastatin; Coronary Vessels; Cyclic GMP; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Echocardiography; Endothelium, Vascular; Heptanoic Acids; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypertrophy, Left Ventricular; Male; Nitrates; Nitrites; Pyrroles; Random Allocation; Swine; Vasodilation; Ventricular Dysfunction, Left

Attenuation of the effects of natriuretic peptides has been demonstrated in animal models but studies in humans are scarce, particularly concerning renal attenuation. We investigated the attenuation of B-type natriuretic peptide (BNP) in chronic advanced heart failure (HF).. We included 62 outpatients with HF and severe left ventricular systolic dysfunction. Cases had at least one hospital admission or emergency department visit for acute HF in the previous year and were in NYHA class III/IV despite optimized therapy. The individual age- and sex-matched controls were symptomatically controlled (NYHA I and II). We collected 24 h urine and a blood sample from all patients. Plasma BNP and plasma (pcGMP) and urine cyclic guanosine monophosphate (ucGMP) were measured. Patients were followed for 3 months for hospital admission or all-cause death. ucGMP to plasma BNP (ucGMP/BNP) ratio was attenuated in cases vs. controls [median (IQR): 8354 (4293-16,456) vs. 12,693 (6896-22,851)]. There were no differences in pcGMP to BNP (pcGMP/BNP) ratio or urine cGMP excretion. Patients with worse outcome had lower pcGMP/BNP [260 (86-344) vs. 381 (244-728) in patients without adverse outcome events] and lower ucGMP/BNP [4146 (2207-9363) vs. 10,922 (7495-19,971)].. Renal NP's second messenger production is attenuated in advanced HF. Patients with worse outcome have lower ucGMP/BNP and pcGMP/BNP ratios.

Topics: Aged; Chronic Disease; Creatinine; Cyclic GMP; Female; Heart Failure; Humans; Male; Natriuretic Peptide, Brain; Second Messenger Systems; Ventricular Dysfunction, Left

Patients with diabetes mellitus exhibit generalized endothelial and cardiac dysfunction with decreased nitric oxide production. Elevated intracellular cyclic guanosine monophosphate (cGMP) levels contribute to an effective cardioprotection in different pathophysiological conditions. In this study, we investigated whether chronic treatment with the phosphodiesterase-5 inhibitor vardenafil could improve diabetic cardiovascular dysfunction by up-regulating the nitric oxide-cGMP pathway in the vessel wall and myocardium.. Diabetes was induced in young rats by a single intraperitoneal injection of streptozotocin (60 mg x kg(-1)). In the treatment group, vardenafil (10 mg x kg(-1) x day(-1)) was given orally for 8 weeks. Diabetic control animals received vehicle for the same time. Left ventricular pressure-volume relations were measured by using a microtip Millar pressure-volume conductance catheter, and indexes of contractility, such as the slope of end-systolic pressure-volume relationship (E(max)) and preload recruitable stroke work (PRSW), were calculated. In organ bath experiments for isometric tension with rings of isolated aortae, endothelium-dependent and independent vasorelaxation was investigated by using acetylcholine and sodium nitroprusside.. When compared with the non-diabetic controls, diabetic rats showed increased myocardial and vascular transforming growth factor-beta1 expression, impaired left ventricular contractility (impairment of E(max) by 53%, PRSW by 40%; P < 0.05) and vascular dysfunction. Treatment with vardenafil resulted in higher cGMP levels, reduced transforming growth factor-beta1 expression, significantly improved cardiac function (improvement of E(max) by 95%, PRSW by 69%; P < 0.05) and greater vasorelaxation to acetylcholine and sodium nitroprusside in aortae from diabetic animals.. Our results demonstrate that impaired vascular cGMP signalling contributes to the development of diabetic vascular and cardiac dysfunction, which can be prevented by chronic phosphodiesterase-5 inhibition.

Topics: Animals; Aorta, Thoracic; Cyclic GMP; Diabetes Mellitus, Experimental; Endothelium, Vascular; Heart; Hemodynamics; Imidazoles; In Vitro Techniques; Isometric Contraction; Muscle, Smooth, Vascular; Myocardial Contraction; Myocardium; Phosphodiesterase 5 Inhibitors; Piperazines; Rats; Rats, Sprague-Dawley; Sulfones; Transforming Growth Factor beta1; Triazines; Vardenafil Dihydrochloride; Vasodilation; Vasodilator Agents; Ventricular Dysfunction, Left

The role of the neuronal NO synthase (nNOS or NOS1) enzyme in the control of cardiac function still remains unclear. Results from nNOS(-/-) mice or from pharmacological inhibition of nNOS are contradictory and do not pay tribute to the fact that probably spatial confinement of the nNOS enzyme is of major importance. We hypothesize that the close proximity of nNOS and certain effector molecules like L-type Ca(2+)-channels has an impact on myocardial contractility. To test this, we generated a new transgenic mouse model allowing conditional, myocardial specific nNOS overexpression. Western blot analysis of transgenic nNOS overexpression showed a 6-fold increase in nNOS protein expression compared with noninduced littermates (n=12; P<0.01). Measuring of total NOS activity by conversion of [(3)H]-l-arginine to [(3)H]-l-citrulline showed a 30% increase in nNOS overexpressing mice (n=18; P<0.05). After a 2 week induction, nNOS overexpression mice showed reduced myocardial contractility. In vivo examinations of the nNOS overexpressing mice revealed a 17+/-3% decrease of +dp/dt(max) compared with noninduced mice (P<0.05). Likewise, ejection fraction was reduced significantly (42% versus 65%; n=15; P<0.05). Interestingly, coimmunoprecipitation experiments indicated interaction of nNOS with SR Ca(2+)ATPase and additionally with L-type Ca(2+)- channels in nNOS overexpressing animals. Accordingly, in adult isolated cardiac myocytes, I(Ca,L) density was significantly decreased in the nNOS overexpressing cells. Intracellular Ca(2+)-transients and fractional shortening in cardiomyocytes were also clearly impaired in nNOS overexpressing mice versus noninduced littermates. In conclusion, conditional myocardial specific overexpression of nNOS in a transgenic animal model reduced myocardial contractility. We suggest that nNOS might suppress the function of L-type Ca(2+)-channels and in turn reduces Ca(2+)-transients which accounts for the negative inotropic effect.

Topics: Animals; Arginine; Caffeine; Calcium; Calcium Channels, L-Type; Calcium Signaling; Cell Size; Cells, Cultured; Citrulline; Cyclic GMP; Doxycycline; Enzyme Induction; Ion Channel Gating; Mice; Mice, Transgenic; Myocardial Contraction; Myocytes, Cardiac; Nitric Oxide Synthase Type I; Ornithine; Protein Interaction Mapping; Recombinant Fusion Proteins; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Stroke Volume; Ultrasonography; Ventricular Dysfunction, Left

Unlike healthy subjects, overt congestive heart failure cannot "escape" the sodium- and water-retaining actions of mineralocorticoid excess. It is undefined whether escape occurs in asymptomatic left ventricular dysfunction (ALVD), which is characterized by preserved sodium homeostasis, natriuretic peptide activation, and normal circulating aldosterone. We hypothesized that, in ALVD, mineralocorticoid excess with exogenous deoxycorticosterone acetate (DOCA) would overwhelm renal compensatory mechanisms, resulting in sodium and water retention, and promote renal and cardiac collagen deposition. ALVD was induced in 2 groups (N=5 each) of dogs by tachypacing at 180 bpm. Urine was collected daily and blood drawn at baseline and days 2, 5, 8, and 11. One group served as control (ALVD), and the other received DOCA (ALVD+DOCA) starting at day 2 of pacing. Urine flow and sodium excretion were unchanged in the ALVD group. In ALVD+DOCA, urine flow and sodium excretion decreased on the first 2 days DOCA was given but normalized starting day 4. Urine flow and urinary cGMP excretion increased in ALVD+DOCA after DOCA escape. Plasma atrial natriuretic peptide, B-type natriuretic peptide, and cGMP increased equally in both groups. There were no differences in cardiorenal and hemodynamic parameters in an acute study on day 11. Although renal collagen area fraction was similar, left ventricular collagen area fraction in ALVD+DOCA was significantly higher than in ALVD (3.3+/-0.4% versus 2.0+/-0.2%; P=0.012). We conclude that ALVD can escape the sodium- and water-retaining effects of mineralocorticoid excess. Despite renal escape, increased left ventricular collagen deposition suggests that the heart but not the kidney failed to escape the tissue effects of DOCA.

Topics: Animals; Body Water; Collagen; Cyclic GMP; Desoxycorticosterone; Diuresis; Dogs; Kidney; Male; Myocardium; Natriuresis; Receptors, Mineralocorticoid; Sodium; Ventricular Dysfunction, Left

Pulmonary hypertension (PH) usually develops secondary to left ventricular (LV) dysfunction; therefore, it is also called retrograde PH. To investigate our hypothesis that PH is at least partially reversible, as in some congenital heart diseases, in a rat model we investigated whether release of constriction could attenuate pulmonary vascular remodeling and change the expression of endothelin (ET)-1 and endothelial nitric oxide synthase (eNOS). We used rats with LV dysfunction produced by an ascending aortic banding. In this study, there were four groups enrolled: 4-weeks banded (AOB(1-28); n = 7), 7-weeks banded (AOB(1-49); n = 7), debanded groups (AOB(1-28)/DeB(29-49); n = 7), and rats receiving a sham operation (n = 7). Subsequently, there was significant attenuation of medial hypertrophy in pulmonary arterioles and reversal of PH in the AOB(1-28)/DeB(29-49) group (sham, 19 +/- 1.3 mm Hg; AOB(1-28), 31 +/- 2.7 mm Hg; AOB(1-49), 32 +/- 2.7 mm Hg; and AOB(1-28)/DeB(29-49), 20 +/- 1.3 mm Hg). PreproET-1 mRNA and eNOS mRNA were measured by competitive reverse transcriptase (RT) polymerase chain reaction (PCR), and eNOS was measured by Western blotting. Compared with the banded groups, debanding significantly decreased pulmonary preproET-1 mRNA, pulmonary ET-1 (sham, 210 +/- 12 pg/g protein; AOB(1-28), 242 +/- 12 pg/g protein; AOB(1-49), 370 +/- 49 pg/g protein; and AOB(1-28)/DeB(29-49), 206 +/- 1.9 pg/g protein), and plasma ET-1 levels (sham, 10.1 +/- 1.5 pg/ml; AOB(1-28), 13.4 +/- 2.0 pg/ml; AOB(1-49), 15.4 +/- 2.0 pg/ml; and AOB(1-28)/DeB(29-49), 10.3 +/- 0.9 pg/ml protein). Debanding could not, however, alter pulmonary eNOS, eNOS mRNA, or cGMP. These findings suggest that pulmonary vascular remodeling, increased pulmonary arterial pressure, and upregulation of ET-1 gene expression are all reversible. We infer that it is the upregulated gene expression of ET-1, not eNOS, that is closely related to the development of the PH secondary to 4 weeks of aortic banding.

Topics: Animals; Cyclic GMP; Disease Models, Animal; Endothelin-1; Hypertension, Pulmonary; Lung; Male; Nitric Oxide Synthase Type III; Rats; Rats, Wistar; Ventricular Dysfunction, Left

The mechanisms by which endotoxemia causes cardiac depression have not been fully elucidated. The present study examined the involvement of nitric oxide (NO) in this pathology. Rats were infused with lipopolysaccharide (LPS) or saline, and the plasma and myocardial NO(2)(-) and NO(3)(-) (NOx) concentrations were measured before or 3, 6, and 24 h after treatment. The hearts were then immediately isolated and mounted in a Langendorff apparatus, and left ventricular developed pressure (LVDP) was determined before biochemical analysis of the myocardium. LPS injection effected the expression of inducible NO synthase (iNOS) in the myocardium, a marked increase in plasma and myocardial NOx levels, and a significant decline in LVDP compared with saline controls. The LPS-induced NO production and concomitant cardiac depression were most pronounced 6 h after LPS injection and were accompanied by a significant increase in myocardial cGMP content. Myocardial ATP levels were not significantly altered after LPS injection. Significant negative correlation was observed between LVDP and myocardial cGMP content, as well as between LVDP and plasma NOx levels. Aminoguanidine, an inhibitor of iNOS, significantly attenuated the LPS-induced NOx production and contractile dysfunction. Furthermore, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, an inhibitor of soluble guanylate cyclase, significantly decreased myocardial cGMP content and attenuated the contractile depression, although aminoguanidine or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one was not able to completely reverse myocardial dysfunction. Our data suggest that endotoxin-induced contractile dysfunction in rat hearts is associated with NO production by myocardial iNOS and a concomitant increase in myocardial cGMP.

Topics: Animals; Cyclic GMP; Endotoxins; In Vitro Techniques; Male; Myocardial Contraction; Myocardium; Nitric Oxide; Rats; Rats, Sprague-Dawley; Signal Transduction; Ventricular Dysfunction, Left

In 15 patients with chronic heart failure of ischemic origin who were not previously treated with angiotensin-converting enzyme inhibitors, platelets exhibited hyperaggregability and impaired responsiveness to the antiaggregatory and cyclic guanosine monophosphate-stimulatory effects of nitric oxide donor sodium nitroprusside compared with normal subjects; this was paralleled by increased blood levels of superoxide radicals. Treatment with perindopril for 4 days significantly improved platelet responses to sodium nitroprusside; there was also a trend toward a decrease in superoxide radical levels.

Topics: Angiotensin-Converting Enzyme Inhibitors; Cyclic GMP; Female; Heart Failure; Humans; Male; Middle Aged; Nitric Oxide; Nitric Oxide Donors; Nitroprusside; Perindopril; Platelet Aggregation; Platelet Function Tests; Superoxides; Time Factors; Ventricular Dysfunction, Left

Based on the role of inducible nitric oxide synthase (iNOS) in heart failure, we hypothesized that the elevated expression of iNOS compared to young mice in the myocardium contributes to the age-related decline of left ventricular (LV) function. Cardiac iNOS mRNA and protein expression was singularly identified in old, wild type (WT) male mice (I6-month) and not in young WT male mice (6-month). Characterized with in vivo pressure-volume loops analysis, an age-related LV dysfunction was found in the old WT mice. The LV dysfunction of the aged mice was modified to that of the younger mice by the specific iNOS inhibitors, aminoguanidine (AMG, 10 mg/Kg, i.v. or infusion, n = 15) and S-methyl-isothiourea (MITU, 3 mg/Kg, i.v. n = 7), and declined with L-arginine (10 mg/Kg, i.v. n = 7). All three drugs had no effects on the LV function of young WT mice or old iNOS knockout (KO) mice. The NOx and cGMP levels were significantly higher only in the old WT mice (n = 6) and cGMP levels decreased to normal with AMG administration. In conclusion, these results suggested that the iNOS/NO/cGMP pathway may contribute to ventricular dysfunction during the aging process and that inhibition of iNOS activity significantly improved heart function in aged mice.

Topics: Aging; Animals; Arginine; Cyclic GMP; Dose-Response Relationship, Drug; Enzyme Inhibitors; Fluorescent Antibody Technique, Indirect; Guanidines; Isothiuronium; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; RNA, Messenger; Ventricular Dysfunction, Left

Vascular reactivity to nitric oxide (NO) is mediated by NO-sensitive soluble guanylyl cyclase (sGC). Since a diminished activity of vascular sGC has been reported in an animal model of type 2 diabetes, the sGC activity was assayed in vitro in internal mammary artery specimens obtained during bypass surgery from patients with and without type 2 diabetes. The sensitivity of sGC to NO, which is dependent on Fe(2+)-containing heme, was measured in vitro using stimulation with diethylamine NONOate (DEA/NO). In addition, the novel cyclic guanosine monophosphate-elevating compound HMR-1766 was used to test the stimulation of the oxidized heme-Fe(3+)-containing form of sGC. Basal activity of sGC and its sensitivity to stimulation by DEA/NO and HMR-1766 were not different between control and type 2 diabetic patients: maximum stimulation by DEA/NO amounted to 475 +/- 67 and 418 +/- 59 pmol. mg(-1). min(-1) in control and type 2 diabetic patients, respectively. The maximum effects of HMR-1766 were 95 +/- 18 (control subjects) and 83 +/- 11 pmol. mg(-1). min(-1) (type 2 diabetic patients). Hypertension, hyperlipidemia, drug treatment with statins, ACE inhibitors, or nitrates had no effect on sGC activity. In conclusion, the present findings do not support the hypothesis that desensitization of sGC contributes to the pathogenesis of diabetic vascular dysfunction in humans.

Topics: Aged; Coronary Disease; Cyclic GMP; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Female; Guanylate Cyclase; Humans; Hydrazines; Male; Mammary Arteries; Middle Aged; Nitric Oxide; Nitric Oxide Donors; Nitrogen Oxides; Ventricular Dysfunction, Left

Staphylococcus aureus sepsis is associated with significant myocardial dysfunction. Toll-like receptor 2 (TLR2) mediates the inflammatory response to S aureus and may trigger an innate immune response in the heart. We hypothesized that a TLR2 deficiency would attenuate S aureus-induced cardiac proinflammatory mediator production and the development of cardiac dysfunction.. Wild-type and TLR2-deficient (TLR2D) mice were studied. S aureus challenge significantly increased tumor necrosis factor, interleukin-1beta, and nitric oxide expression in hearts of wild-type mice. This response was significantly blunted in TLR2D mice. Hearts from TLR2D mice had impaired S aureus-induced activation of interleukin-1 receptor-associated kinase, c-Jun NH2 terminal kinase, nuclear factor-kappaB, and activator protein-1. Moreover, hearts from TLR2D mice were protected against S aureus-induced contractile dysfunction.. These results show for the first time that TLR2 signaling contributes to the loss of myocardial contractility and cytokine production in the heart during S aureus sepsis.

Topics: Animals; Child; Cyclic GMP; Cytokines; Heart; Humans; Interleukin-1; Mice; Mice, Knockout; Myocardial Contraction; Myocardium; Nitric Oxide; Receptors, Cell Surface; Signal Transduction; Staphylococcal Infections; Staphylococcus aureus; Toll-Like Receptor 2; Tumor Necrosis Factor-alpha; Ventricular Dysfunction, Left

The impaired ability to excrete sodium is a key feature of established congestive heart failure and is also apparent in asymptomatic left ventricular (LV) impairment. However, few studies have examined responses to chronic volume loading immediately post-myocardial infarction (MI). Experimental MI was induced in six sheep by thrombogenic coil coronary artery occlusion, and resulted in significant LV dysfunction with reduced LV ejection fraction ( P =0.001) and subsequent remodelling (increased LV volumes, P =0.015). Chronic volume loading with 2, 3 and 4 litres/day intravenous saline (each for 7 days) showed no evidence of renal sodium or volume retention in sheep with experimental MI compared with six normal control sheep. Plasma levels of brain natriuretic peptide (BNP), N-terminal pro-BNP and cGMP (all P <0.05) were higher in the MI group compared with normal control sheep. There were no differences in haemodynamics, body mass or renin-aldosterone levels between groups. This study provides evidence that natriuretic peptides play a pivotal role in preserving volume/electrolyte balance in the early stages of post-MI cardiac dysfunction.

Topics: Animals; Chronic Disease; Cyclic GMP; Female; Homeostasis; Models, Animal; Myocardial Infarction; Natriuretic Peptide, Brain; Sheep; Sodium; Sodium Chloride; Ventricular Dysfunction, Left

Brain natriuretic peptide (BNP) is released into circulation in response to ventricular dilatation and pressure overload. Plasma BNP concentration correlates with left ventricular mass and dysfunction, which is prevalent in hemodialysis (HD) patients.. To evaluate the potential of BNP level for determination of hydration status, we measured inferior vena caval diameter (IVCD) and BNP levels and performed bioimpedance analysis in 49 HD patients.. Pre-HD BNP levels remained unchanged after HD. Agreement between IVCD and pre-HD BNP level in overhydration was significant (kappa = 0.304). The area under the receiver operating characteristic (ROC) curve for overhydration was 0.819 for pre-HD BNP level. When extracellular fluid/total-body water (ECF/TBW) ratios of HD patients were compared with those of 723 controls, pre- and post-HD BNP levels were significantly greater in overhydrated patients. The area under the ROC curve for overhydration by ECF/TBW ratio was 0.781 for pre-HD BNP level. However, there was no significance for pre- or post-HD BNP levels on assessment of normohydration or underhydration. Pre-HD BNP level correlated significantly with post-HD BNP level, post-HD diastolic blood pressure, pulse pressure, and ECF/TBW ratio. IVCD correlated significantly with post-HD BNP level.. BNP level seems to have a limited potential for assessment of overhydration in HD patients.

Topics: Adult; Aged; Atrial Natriuretic Factor; Biomarkers; Body Water; Cyclic GMP; Diabetic Nephropathies; Electric Impedance; Extracellular Fluid; Female; Humans; Kidney Failure, Chronic; Male; Middle Aged; Natriuretic Peptide, Brain; Renal Dialysis; ROC Curve; Sensitivity and Specificity; Ultrasonography; Vena Cava, Inferior; Ventricular Dysfunction, Left; Water Intoxication

The molecular mechanisms responsible for sepsis-induced myocardial dysfunction remain undefined. CD14 mediates the inflammatory response to lipopolysaccharide (LPS) in various organs including the heart. In this study we investigated the role of CD14 in LPS-induced myocardial dysfunction in vivo.. Wild-type and CD14-deficient (CD14-D) mice were challenged with Escherichia coli LPS. Myocardial tumor necrosis factor, interleukin-1beta (IL-1beta), and NOS2 induction was measured before and 6 hours after LPS challenge. Echocardiographic parameters of left ventricular function were measured before and 6 hours after LPS administration. LPS challenge induced a significant increase in myocardial tumor necrosis factor and IL-1beta mRNA and protein expression in wild-type mice. In contrast, mRNA and protein levels for TNF and IL-1beta were significantly blunted in CD14-D mice. An increase in NOS2 protein was noted within 6 hours of LPS provocation only in the hearts of wild-type mice. This was associated with an increase in ventricular cGMP levels. Activation of nuclear factor-kappaB was observed within 30 minutes of LPS in the hearts of wild-type mice but not in CD14-D mice. In wild-type mice, LPS significantly decreased left ventricular fractional shortening, velocity of circumferential shortening, and dP/dt(max). LPS-treated CD14-D mice maintained normal cardiac function.. These results suggest that CD14 is important in mediating the proinflammatory response induced by LPS in the heart and that CD14 is necessary for the development of left ventricular dysfunction during LPS-induced shock in vivo.

Topics: Animals; Cyclic GMP; Female; Heart Ventricles; Hemodynamics; Inflammation; Interleukin-1; Lipopolysaccharide Receptors; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardium; NF-kappa B; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; RNA, Messenger; Shock, Septic; Tumor Necrosis Factor-alpha; Ultrasonography; Ventricular Dysfunction, Left

Growth hormone (GH) application is a new strategy in the treatment of heart failure. However, clinical and experimental investigations have shown contradictory effects of GH on cardiac performance. We tested the hypothesis that GH could improve cardiac and renal function in volume overload-induced heart failure. The effect of 4 weeks of GH treatment (2 mg/kg daily) was investigated in Wistar rats with aortocaval shunt. GH application did not influence left ventricular contractility and end-diastolic pressure in rats with aortocaval shunt. In contrast, GH treatment normalized impaired diuresis (vehicle 10.8+/-0.6 mL/d, GH 15.8+/-0.7 mL/d; P<0.05) and sodium excretion (vehicle 1.5+/-0.1 mmol/d, GH 2.2+/-0.1 mmol/d; P<0.001) in shunt-operated rats, with a similar increase of fractional sodium excretion. The urinary excretion of cGMP, the second messenger of atrial natriuretic peptide and NO, was higher in animals with shunts than in sham-operated animals and was further increased by GH (vehicle 293+/-38 nmol/d, GH 463+/-57 nmol/d; P<0.01). Although the atrial natriuretic peptide plasma levels were unchanged after GH, the excretion of NO metabolites (nitrate/nitrite) was elevated (vehicle 2020+/-264 nmol/d, GH 2993+/-375 nmol/d; P<0.05) in parallel with increased renal mRNA levels of inducible NO synthase 2. The changes of renal function after GH and the increased excretion of NO metabolites and cGMP were abolished by simultaneous treatment with the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester. GH treatment did not influence cardiac function in rats with aortocaval shunts. However, GH improved renal function by increasing diuresis and sodium excretion. The responsible mechanism might be the enhanced activity of the renal NO system.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Body Weight; Cyclic GMP; Enzyme Inhibitors; Growth Hormone; Heart; Heart Failure; Human Growth Hormone; Humans; Insulin-Like Growth Factor I; Kidney; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type III; Organ Size; Rats; Rats, Wistar; Recombinant Proteins; RNA, Messenger; Ventricular Dysfunction, Left

Recent studies suggest that female gender is associated with a lower prevalence and a more benign prognosis of heart failure. In the current population-based study, it was our objective to evaluate the implications of gender on the association between impaired left ventricular (LV) function and mass as well as neurohumoral activation.. A total of 1883 subjects (992 female, 891 male) of two MONICA surveys in Augsburg, Germany, were analyzed. Participants of one of these surveys were additionally characterized with respect to neurohormonal activation. As compared to men, women were characterized by a slightly higher LV ejection fraction (EF, Teichholz-Method, 65.4 +/- 0.3% vs. 63.4 +/- 0.3, P<0.01) and a markedly lower LV mass index (LVMI 81 +/- 1 g/m(2) vs. 96 +/- 1, P<0.01). As compared to men with normal LV function, those with LV dysfunction (EF below mean minus two standard deviations, S.D.) were characterized by significantly increased LV mass (LVMI +48%, P<0.01), plasma BNP (+373%, P<0.01) and ANP (+57%, P<0.01), while no significant changes were observed in women (LVMI +3%, BNP +48%, ANP +27%, all P=n.s). Only a small subgroup of women with severe LVD (EF below mean - 3 S.D.) was characterized by significantly increased LV mass (LVMI +23%, P<0.05 vs. control and LVD), however, this increase was less pronounced as compared to men with severe LVD (LVMI +46%, P<0.01 vs. control). Gender-specific differences between LV function and structure were also confirmed by multivariate analysis. While LVMI was independently and significantly correlated with EF in male subjects in addition to systolic blood pressure, age, and body mass index (all P<0.01), these parameters displaced EF as a predictor of LVMI in female subjects.. Men with moderate or severe LV dysfunction are characterized by an increase in both LV mass and cardiac natriuretic peptide plasma concentrations. In contrast, LV mass and natriuretic peptide concentrations increase to a lesser extent and only with severe LV dysfunction in women. These observational data suggest gender-specific control of myocardial adaptations to hemodynamic overload and a more rapid induction of LV hypertrophy during myocardial dysfunction in male subjects.

Topics: Atrial Natriuretic Factor; Cardiomegaly; Cohort Studies; Cyclic GMP; Echocardiography; Female; Humans; Male; Regression Analysis; Renin; Sex; Ventricular Dysfunction, Left; Ventricular Remodeling

The precise molecular mechanisms responsible for sepsis-induced myocardial dysfunction remain undefined. Toll-like receptor-4 (TLR-4) engages lipopolysaccharide (LPS) and activates signaling pathways leading to the expression of proinflammatory cytokines implicated in myocardial dysfunction. We determined whether TLR-4 was necessary for LPS-induced myocardial dysfunction in vivo. The effects of LPS on left ventricular (LV) function were studied in mice with defective TLR-4 signaling (C3H/HeJ, TLR-4 deficient) and wild-type mice (C3HeB/FeJ). Mice (n = 5/group) were injected with LPS or diluent, and LV function was examined by using two-dimensional echocardiography and conductance catheters. LPS significantly decreased all indexes of LV function in wild-type mice when compared with controls; LV function was not depressed in the LPS-treated TLR-4-deficient mice relative to controls. LPS increased myocardial nitric oxide synthase-2 expression and cGMP only in wild-type mice. This study suggests that TLR-4 mediates the LV dysfunction that occurs in LPS-induced shock. Therefore, TLR-4 might be a therapeutic target for attenuating the effects of LPS on the heart.

Topics: Animals; Cardiac Catheterization; Cyclic GMP; Drosophila Proteins; Echocardiography, Doppler; Escherichia coli; Female; Heart; Heart Ventricles; Hemodynamics; Lipopolysaccharides; Membrane Glycoproteins; Mice; Mice, Inbred C3H; Mutation, Missense; Myocardium; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Receptors, Cell Surface; Signal Transduction; Toll-Like Receptor 4; Toll-Like Receptors; Ventricular Dysfunction, Left

To determine the relations of plasma levels of brain natriuretic peptide (BNP), atrial natriuretic factor (ANF), N-terminal ANF (N-ANF), cyclic guanosine monophosphate (cGMP; the cardiac peptide second messenger), and plasma catecholamines to left ventricular function and to prognosis in patients admitted with acute myocardial infarction.. Plasma hormones and ventricular function (radionuclide ventriculography) were measured 1-4 days after myocardial infarction in 220 patients admitted to a single coronary care unit. Radionuclide scanning was repeated 3-5 months after infarction. Clinical events were recorded over a mean period of 14 months.. Both early and late left ventricular ejection fraction (LVEF) were most closely related to plasma BNP (r = -0.60, n = 220, p < 0.001; and r = -0.53, n = 192, p < 0.001, respectively), followed by ANF, N-ANF, cGMP, and the plasma catecholamines. Early plasma BNP concentrations less than twofold the upper limit of normal (20 pmol/l) had 100% negative predictive value for LVEF < 40% at 3-5 months after infarction. In multivariate analysis incorporating all the neurohormonal factors, only BNP remained independently predictive of LVEF < 40% (p < 0.005). Survival analysis by median levels of candidate predictors identified BNP as the most powerful discriminator for death (p < 0.0001). No early deaths (within 4 months) occurred in patients with plasma BNP concentrations below the group median (27 pmol/l), and over follow up only three of 26 deaths occurred in this subgroup. Of all episodes of left ventricular failure, 85% occurred in patients with plasma BNP above the median (p < 0.001). In multivariate analyses, BNP alone gave additional predictive information beyond sex, age, clinical history, LVEF, and plasma noradrenaline for both subsequent onset of LVF and death.. Plasma BNP measured within 1-4 days of acute myocardial infarction is a powerful independent predictor of left ventricular function, heart failure, or death over the subsequent 14 months, and superior to ANF, N-ANF, cGMP, and plasma catecholamines.

Topics: Atrial Natriuretic Factor; Biomarkers; Cyclic GMP; Epinephrine; Female; Heart; Heart Failure; Humans; Male; Middle Aged; Myocardial Infarction; Natriuretic Peptide, Brain; Norepinephrine; Predictive Value of Tests; Prospective Studies; Protein Precursors; Radionuclide Imaging; Ventricular Dysfunction, Left

Screening for patients with asymptomatic left ventricular dysfunction is of considerable importance because they may benefit from early treatment with angiotensin converting enzyme inhibitors. It has been suggested that atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and cyclic guanosine 3',5'-monophosphate (cGMP) might be useful markers for screening.. To compare directly the power of the three immunoreactive forms of ANP (CT-ANP, beta-ANP, NT-ANP) and BNP and cGMP to detect asymptomatic left ventricular dysfunction.. Radionuclide ventriculography was used to study left ventricular ejection fraction in 37 patients with asymptomatic left ventricular dysfunction, 32 patients with mild to moderate congestive heart failure, and 38 controls. CT-ANP, NT-ANP, beta-ANP, BNP, and cGMP were measured at rest and 3 minutes after exercise. Plasma BNP was the most sensitive marker for patients with asymptomatic left ventricular dysfunction but it reached only a sensitivity of 58% and a specificity of 76% at rest and a sensitivity of 65% and a specificity of 84% after exercise. Combined measurements of all natriuretic peptides and cGMP did not improve the power to detect asymptomatic left ventricular function above that of a single BNP measurement.. Although natriuretic peptides and cGMP measured at rest and three minutes after ergometry may be useful for monitoring left ventricular dysfunction they are unlikely to be suitable for more general routine screening for completely asymptomatic left ventricular dysfunction.

Topics: Adult; Aged; Atrial Natriuretic Factor; Biomarkers; Cyclic GMP; Exercise Test; Female; Humans; Male; Middle Aged; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Prospective Studies; Sensitivity and Specificity; Ventricular Dysfunction, Left

Increased plasma concentrations of cyclic guanosine monophosphate (cGMP) have been reported in patients with manifest heart failure. At rest, however, cGMP concentrations in patients with asymptomatic left ventricular dysfunction or heart failure in New York Heart Association (NYHA) functional class I do not differ significantly from those of healthy subjects. The purpose of this study was to investigate whether graded exercise on an ergometer improves the sensitivity of cGMP in diagnosing asymptomatic left ventricular dysfunction.. Plasma cGMP concentrations were compared in 17 healthy controls and 98 patients with asymptomatic left ventricular dysfunction or congestive heart failure of different stages (asymptomatic left ventricular dysfunction or NYHA functional class I, 56 patients; NYHA class II, 31 patients; NYHA class III, 11 patients).. Before exercise plasma cGMP concentrations in patients with clinical heart failure (NYHA functional classes II and III) were significantly higher than those in healthy controls. In patients with asymptomatic left ventricular dysfunction or heart failure of functional class I plasma cGMP concentrations were not significantly different from those in healthy subjects. Thirty minutes after exercise, however, cGMP concentrations in patients with asymptomatic left ventricular dysfunction or class I heart failure were significantly higher than those in healthy controls.. Measurement of plasma cGMP concentrations 30 minutes after ergometric exercise testing allows better discrimination between healthy subjects and patients with symptomless left ventricular dysfunction or mild heart failure (NYHA class I) than measurement of such concentrations before exercise.

Topics: Adult; Aged; Biomarkers; Cyclic GMP; Exercise Test; Female; Heart Failure; Humans; Male; Middle Aged; Predictive Value of Tests; Time Factors; Ventricular Dysfunction, Left

Asymptomatic or early left ventricular dysfunction in humans is characterized by increases in circulating atrial natriuretic peptide (ANP) without activation of the renin-angiotensin-aldosterone system (RAAS). We previously reported a canine model of early left ventricular dysfunction (ELVD) produced by rapid ventricular pacing and characterized by an identical neurohumoral profile and maintenance of the natriuretic response to volume expansion (VE). To test the hypothesis that elevated endogenous ANP suppresses the RAAS and maintains sodium excretion in ELVD, we assessed the effects of antagonism of ANP on cardiorenal and neurohumoral function in ELVD. Chronic ANP suppression was produced by bilateral atrial appendectomies before the production of ELVD by rapid ventricular pacing (ELVD-APPX, n = 5). This group was compared with a separate group with ELVD and intact atrial appendages (ELVD-INTACT, n = 8). ELVD-APPX was characterized by lower circulating ANP (50 +/- 11 vs. 158 +/- 37 pg/ml, P < 0.05), activation of plasma renin activity (PRA) (9.4 +/- 2.4 vs. 0.6 +/- 0.4 ng/ml per h, P < 0.05) and aldosterone (36.4 +/- 12.5 vs. 2.5 +/- 0.0 ng/dl, P < 0.05) when compared to ELVD-INTACT. In comparison to the ELVD-INTACT group, sodium excretion was decreased before and during VE in the ELVD-APPX group. Acute ANP antagonism was produced by administration of the particulate guanylate cyclase coupled natriuretic peptide receptor antagonist, HS-142-1, to seven conscious dogs with ELVD and intact atrial appendages (ELVD-INTACT). HS-142-1 decreased plasma concentrations and renal generation of the ANP second messenger, cGMP, and was associated with activation of PRA and sodium retention with enhanced tubular sodium reabsorption. These data support a significant role for elevated endogenous ANP in the maintenance of sodium excretion and regulation of the RAAS in experimental ELVD.

Topics: Aldosterone; Animals; Atrial Natriuretic Factor; Cyclic GMP; Disease Models, Animal; Dogs; Heart Atria; Hemodynamics; Kidney; Male; Polysaccharides; Renin; Renin-Angiotensin System; Second Messenger Systems; Ventricular Dysfunction, Left

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

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