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Query: UMLS:C0018801 (
heart failure
)
72,216
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Idiopathic dilated cardiomyopathy (DCM) is characterised by a severe dysfunction of the heart muscle resulting in terminal
heart failure
. Its pathogenesis is believed to be multifactorial involving genetic predisposition, viral infection and autoimmunity, but little is known in detail, and there is no curative treatment except transplantation. Interleukin-1 (IL-1) mediates inflammatory responses to infection and injury. It can be produced by several widely-distributed cell types, including macrophages, and is thought to depress myocyte contractility by stimulating
nitric oxide synthase
. To investigate whether this pro-inflammatory cytokine may be a pathogenic mediator in DCM, IL-1beta mRNA and protein were evaluated in coronary arteries and myocardium from patients undergoing cardiac transplantation for DCM.IL-1beta mRNA was detected by PCR of cDNA and northern blots of mRNA in coronary arteries and myocardium from patients with DCM. By comparison, samples from patients with ischaemic heart disease (IHD) contained much less IL-1beta mRNA. In contrast, mRNA for other cytokines (TNFalpha, IL-6, IL-10, PDGFA) were similar in both pathologies. In DCM, IL-1beta mRNA and protein were localised to infiltrating macrophages in interstitial regions between myocytes, some of the myocytes themselves, and endothelial cells of vessels in the wall of the arteries. These results suggest that local production of the pro-inflammatory cytokine, IL-1beta may play a part in the pathogenesis of DCM.
...
PMID:Interleukin-1 in myocardium and coronary arteries of patients with dilated cardiomyopathy. 951 98
Recently, we have demonstrated a decreased neuronal isoform of
nitric oxide synthase
(nNOS) message in the hypothalamus of rats with
heart failure
(HF). The purpose of this study was to determine the changes in
NADPH-diaphorase
(a commonly used marker for neuronal NOS activity) positive neurons in specific hypothalamic sites of rats with HF. After a standard histochemical protocol, NOS positive neurons were measured in paraventricular nucleus (PVN), supraoptic nucleus (SON), median preoptic area (MePO), subfornical organ (SFO), organum vasculosum of the lamina terminalis (OVLT) and lateral hypothalamus (LH) of rats with coronary artery ligation (HF group; n=8) and sham-operated control rats (n=9). A total of 4 months after coronary ligation, the rats in the HF group displayed infarcts greater than at least 35% of the left ventricular wall (n = 8). Sham-operated rats had no observable damage to the myocardium. Rats with HF had a significantly lower number of NOS positive cells in the PVN (36% less) compared to sham rats. The number of NOS positive cells remained unaltered in the SON, MePO and LH in rats with HF. Conversely there was an increased number of NOS positive cells in the SFO (42% greater) and OVLT (100% greater). These data support the conclusion that the NO system within the hypothalamus involved in controlling autonomic outflow is altered during HF and may contribute to the elevated levels of vasopressin and sympatho-excitation commonly observed in HF.
...
PMID:Altered number of diaphorase (NOS) positive neurons in the hypothalamus of rats with heart failure. 955 24
Congestive heart failure(CHF) is associated with a marked decrease in cortical blood flow and preservation of medullary blood flow. In the present study we tested the hypothesis that changes in the endothelin (ET) and nitric oxide (NO) systems in the kidney may contribute to the altered intrarenal hemodynamics in rats with aortocaval fistula, an experimental model of CHF. Cortical and medullary blood flow were measured simultaneously by laser-Doppler flowmetry in controls and rats with compensated and decompensated CHF. As previously reported [K. Gurbanov, I. Rubinstein, A. Hoffman, Z. Abassi, O. S. Better, and J. Winaver. Am. J Physiol. 271 (Renal Fluid Electrolyte Physiol. 40): F1166-F1172, 1996], administration of ET-1 in control rats produced a sustained cortical vasoconstriction and a transient medullary vasodilatory response. In rats with decompensated CHF, cortical vasoconstriction was severely blunted, whereas ET-1-induced medullary vasodilation was significantly prolonged. This prolonged response was mimicked by IRL-1620, a specific ETB agonist, and partially abolished by
NO synthase
(
NOS
) blockade. In line with these findings, expression of ET-1, ETA and ETB receptors, and endothelial
NOS
(eNOS), assessed by RT-PCR, and eNOS immunoreactivity, assessed by Western blotting, was significantly higher in the medulla than in the cortex. Moreover, expression of ET-1 mRNA in the cortex and eNOS mRNA in the cortex and the medulla increased in proportion to the severity of
heart failure
. These findings indicate that CHF is associated with altered regulation of intrarenal blood flow, which reflects alterations in expression and activity of the ET and NO systems. It is further suggested that exaggerated NO activity in the medulla contributes to preservation of medullary blood flow in the face of cortical vasoconstriction in CHF.
...
PMID:Regulation of intrarenal blood flow in experimental heart failure: role of endothelin and nitric oxide. 957 2
Endogenous nitric oxide (NO) signalling pathways within the myocardium depress myocardial contractile function in septic shock and some cardiomyopathies. We have explored the role of NO synthases (NOSs) in mediating the cardiodepressant actions of interferon-gamma (IFN-gamma) and lipopolysaccaride (LPS) in rat papillary muscle. Muscles from the right ventricle were electrically stimulated (0.2 Hz) at 30 degrees C and isometric contraction monitored. Exposure to IFN-gamma and LPS for 15 h in vitro significantly decreased the peak tension (PT for IFN-gamma + LPS, from 0.13 +/- 0.03 to 0.07 +/- 0.02 g) and rate of tension development (dT/dt for IFN-gamma + LPS, from 1.78 +/- 0.36 to 1.17 +/- 0.28 g/s) compared to untreated controls, and this was prevented by dexamethasone (1 microM) and partly reversed by a non-specific
NOS
inhibitor, NG-nitro-L-arginine (NOLA, 30 microM). Likewise, the maximum inotropic response of the papillary muscles to isoprenaline (0.001-10 microM) decreased significantly after 15 h treatment with IFN-gamma and LPS (PT from 83 +/- 18 to 28 +/- 6%; +dT/dt from 83 +/- 12 to 31 +/- 7%; -dT/dt from 83 +/- 12 to 38 +/- 6%). Again, the depressant effects of IFN-gamma and LPS on inotropic responsiveness to isoprenaline were completely prevented by pretreatment with dexamethasone (1 microM), by a specific inhibitor of NOS2, mercaptoethylguanidine (MEG, 30 microM) and by NOLA. Whereas dexamethasone and NOLA protected against the attenuation of baseline contractions induced by LPS and IFN-gamma, MEG did not. Western blot analysis of cardiac myocytes showed that there was no constitutive expression of NOS2, but IFN-gamma and LPS induced expression of NOS2, and this was prevented by dexamethasone. Thus IFN-gamma, in the presence of LPS, reduced papillary muscle contraction and decreased responsiveness to beta-adrenoceptor stimulation through induction of NOS2 in the muscle. Increased NO production may contribute to the cardiac depression during septic shock and anti-cancer therapy with cytokines, and perhaps in
heart failure
.
...
PMID:Cardiodepressant effects of interferon-gamma and endotoxin reversed by inhibition of NO synthase 2 in rat myocardium. 961 39
Nitric oxide (NO) plays a role in controlling vascular tone and regulates the contractile properties of cardiac myocytes. Patients with
heart failure
exhibit high plasma levels of nitrite/nitrate (NOx), a stable metabolite of NO, and of cytokines such as tumor necrosis factor-alpha, a potent inducer of
NO synthase
. An increase in inducible
NO synthase
activity has been found in cardiac tissue from patients with dilated cardiomyopathy. These findings raise the possibility that local or systemic overproduction of NO induced by cytokines exerts a chronic negative inotropic effect on the myocardium and may have detrimental effects on systemic hemodynamics in patients with
heart failure
. Plasma levels of NG,NG-dimethylarginine (asymmetric dimethylarginine; ADMA), a circulating endogenous
NO synthase
inhibitor, were measured in control subjects and patients with valvular, hypertensive, or ischemic heart diseases or idiopathic cardiomyopathy. The plasma levels of NOx and ADMA were assessed by high performance liquid chromatography. The plasma levels of NOx and ADMA were significantly elevated in patients with
heart failure
. Both NOx and ADMA were positively correlated with New York Heart Association functional class. There was a significant inverse correlation between plasma NOx and ejection fraction, as estimated by echocardiography. A significant relationship between plasma NOx and ADMA was found only in patients with moderate to severe
heart failure
(r=0.41, p=0.01). Findings suggest a compensatory role of a circulating endogenous
NO synthase
inhibitor against induced
NO synthase
activity in patients with
heart failure
.
...
PMID:Increased endogenous nitric oxide synthase inhibitor in patients with congestive heart failure. 965 Nov 9
1. Endothelium-dependent vasodilatation via nitric oxide in response to muscarinic stimulation is decreased in chronic
heart failure
while basal release of nitric oxide may be increased. As production of the endothelium-derived vasoconstrictor endothelin-1 is increased in chronic
heart failure
, endothelin-1 may act in an autocrine manner to modulate these effects. 2. To test this, we determined whether prolonged endothelin infusion in normal subjects would reproduce the alterations in basal and stimulated nitric oxide release observed in patients with chronic
heart failure
. Basal nitric oxide production was determined by measurement of forearm blood flow using strain gauge venous occlusion plethysmography before and after brachial artery infusion of a
nitric oxide synthase
inhibitor (NG-monomethyl-L-arginine). Stimulated nitric oxide production was determined by brachial artery infusion of acetylcholine. As metabolic vasodilatation is thought to be mediated in part via nitric oxide and is decreased in chronic
heart failure
, forearm blood flow during peak reactive hyperaemia was also measured. Studies were then repeated during brachial artery infusion of endothelin-1 and a non-specific vasoconstrictor, noradrenaline. 3. Neither basal nor stimulated nitric oxide production was altered by endothelin-1 and noradrenaline infusion. However, absolute forearm blood flow responses to peak reactive hyperaemia were decreased during infusion of endothelin-1 in comparison to noradrenaline. These data suggest that increased endothelin-1 may not contribute greatly to altered basal and stimulated nitric oxide production in patients with chronic
heart failure
but may contribute to impaired metabolic vasodilatation, by mechanisms presumably unrelated to altered nitric oxide production.
...
PMID:Effect of endothelin-1 on endothelium-derived vascular responsiveness in man. 968 Apr 96
I have shown that cardiac sympathetic afferent stimulation by epicardial application of bradykinin (BK) was significantly enhanced in pacing-induced
heart failure
(HF) dogs. This enhancement appeared to be mediated by prostaglandins. The present study was to determine whether nitric oxide is involved in this enhancement. Under alpha-chloralose (100 mg/kg iv) anesthesia, the renal sympathetic nerve activity (RSNA) response to BK was determined in 15 HF and 15 sham dogs in the sinoaortic-denervated and vagotomized state. The RSNA response to BK was significantly enhanced in HF. This enhanced RSNA response to BK was significantly reduced in the HF dogs after administration of the cycloxygenase inhibitor indomethacin (5 mg/kg iv), but no significant change was found in the sham group. In contrast, RSNA responses to BK were significantly reduced in the sham dogs after administration of the
nitric oxide synthase
inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 30 mg/kg iv), but no significant change was found in the HF group. These data suggest that the RSNA response to BK is mediated by nitric oxide to a large degree in the normal state but is primarily mediated by prostaglandins in the HF state.
...
PMID:Cardiac sympathetic afferent stimulation by bradykinin in heart failure: role of NO and prostaglandins. 972 80
An inducible isoform of
nitric oxide synthase
(type II, iNOS) is expressed in cardiac and vascular smooth muscle in response to inflammatory cytokines. The dog is an important large animal used for cardiovascular research including effects of exercise,
heart failure
, and allograft rejection. However, molecular probes for iNOS developed in other mammals have not been reliable for the study of iNOS induction in canine vascular smooth muscle. Experiments were designed to develop a molecular probe for canine iNOS. Smooth muscle cells were isolated from canine aortas. The cells (passages 3-10) were incubated for 1, 3, 6, 12, 24, 48, or 72 h in the absence and presence of Escherichia coli lipopolysaccharide (LPS) to induce iNOS. Total RNA was isolated from the cells using standard techniques. RT-PCR with primers against conserved regions of all known iNOS enzyme was used to clone the iNOS cDNA. RT-PCR showed a single band only from cells treated with LPS. Cloned cDNA from cultured canine aortic smooth muscle cells has 84% homology to human, 81% to rat, and 81% to mouse iNOS gene. Identification of the cDNA for canine iNOS will be useful in the study of differential, transcriptional regulation of inducible (type II) compared with constitutive endothelial (type III) NOS in canine studies of allograft rejection and cardiovascular disease.
...
PMID:Induction and cDNA sequence of inducible nitric oxide synthase from canine aortic smooth muscle cells. 974 58
Vascular responses were studied in both large and small arteries of rats following 8 weeks of
heart failure
produced by coronary ligation. Responses to noradrenaline, acetylcholine and sodium nitroprusside were studied in isolated thoracic aorta and mesenteric arteries. In the aorta, concentration-response curves for noradrenaline were similar between
heart failure
and sham animals and unaffected by the
nitric oxide synthase
inhibitor, NG-nitro-L-arginine (L-NOARG). Relaxation by acetylcholine was impaired in
heart failure
rats (EC50-6.79 log M
heart failure
vs. -7.15 log M sham). In the presence of L-NOARG, relaxation by acetylcholine was completely abolished in rings from sham rats, whereas constriction was observed in rings from
heart failure
rats. Relaxation by sodium nitroprusside was not different between sham and
heart failure
rats. In mesenteric arteries, responses to noradrenaline, acetylcholine and sodium nitroprusside were not different between
heart failure
and sham rats. L-NOARG reduced the maximum response to acetylcholine in both
heart failure
(82% to 50%) and shams (89% to 49%) by a similar magnitude, with no effect on relaxation to sodium nitroprusside. These data suggest that acetylcholine-induced relaxation is impaired in the aorta, but not mesenteric arteries in rats with
heart failure
. The mechanism is not solely due to impaired nitric oxide release and may be due to acetylcholine-induced contraction.
...
PMID:Impaired endothelium-dependent relaxation in large, but not small arteries in rats after coronary ligation. 976 31
The aim of the present study was to determine whether cardiac nitric oxide (NO) production changes during the progression of pacing-induced
heart failure
and whether this occurs in association with alterations in myocardial metabolism. Dogs (n=8) were instrumented and the heart paced until left ventricular end-diastolic pressure reached 25 mm Hg and clinical signs of severe failure were evident. Every week, hemodynamic measurements were recorded and blood samples were withdrawn from the aorta and the coronary sinus for measurement of NO metabolites, O2 content, free fatty acids (FFAs), and lactate and glucose concentrations. Cardiac production of NO metabolites or consumption of O2 or utilization of substrates was calculated as coronary sinus-arterial difference times coronary flow. In end-stage failure, occurring at 29+/-1.6 days, left ventricular end-diastolic pressure was 25+/-1 mm Hg, left ventricular systolic pressure was 92+/-3 mm Hg, mean arterial pressure was 75+/-2.5 mm Hg, and dP/dtmax was 1219+/-73 mm Hg/s (all P<0.05). These changes in hemodynamics were associated with a fall of cardiac NO metabolite production from 0.37+/-0.16 to -0.28+/-0.13 nmol/beat (P<0.05). O2 consumption and lactate uptake did not change significantly from control, while FFA uptake decreased from 0.16+/-0.03 to 0.05+/-0.01 microEq/beat and glucose uptake increased from -2.3+/-7.0 to 41+/-10 microgram/beat (P<0.05). The cardiac respiratory quotient also increased significantly by 28%. In 14 normal dogs the same measurements were performed at control and 1 hour after we injected 30 mg/kg of nitro-L-arginine, a competitive inhibitor of
NO synthase
.O2 consumption increased from 0.05+/-0.002 mL/beat at control to 0.071+/-0.003 mL/beat after nitro-L-arginine, while FFA uptake decreased from 0.1+/-0.01 to 0.06+/-0.01 microEq/beat, lactate uptake increased from 0.15+/-0.04 to 0.31+/-0.03 micromol/beat, glucose uptake increased from 8.2+/-5.0 to 35.4+/-9.5 microgram/beat, and RQ increased by 23% (all P<0.05). Our results indicate that basal cardiac production of NO falls below normal levels during cardiac decompensation and that there are shifts in substrate utilization. This switch in myocardial substrate utilization also occurs after acute pharmacological blockade of NO production in normal dogs.
...
PMID:Reduced nitric oxide production and altered myocardial metabolism during the decompensation of pacing-induced heart failure in the conscious dog. 981 54
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