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Query: UMLS:C0018801 (heart failure)
 72,216 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The majority of patients with chronic heart failure (CHF) have a decreased exercise tolerance. It has not been well established if muscle fatigue is related to a peripheral myopathy with specific metabolic, histologic and biochemical abnormalities. CHF patients demonstrate depressed oxidative capacity and activation of anaerobic glycolysis, leading to a reduction in the energy substrates. In addition, the skeletal muscles of the lower limbs demonstrate a shift toward type IIb fibers. Many factors, such as prolonged immobilization, reduced blood flow and neuroendocrine activation, can be cited in order to explain the origin of this myopathy. Recent studies show that immobilization is not the only reason for modifications in skeletal muscle composition, since patients with disuse atrophy show an increased percentage in myosin heavy chain I, while IIb is decreased. The opposite pattern is observed in CHF. It would appear that several factors such as deconditioning, prolonged immobilization and reduced blood flow, may produce muscular atrophy. The reasons behind specific changes in fibre composition may be found in metabolic factors such as insulin resistance, TNF levels and dysfunction of the ergo-metabolo muscle receptors.
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PMID:[Skeletal musculature modifications and mechanisms of fatigue in chronic heart failure]. 928 Jul 30

Malnutrition and hypoalbuminemia, which are prevalent in patients with end-stage renal disease (ESRD), are strong predictors of increased mortality. However, cardiovascular disease predominates among direct causes of death, whereas malnutrition appears to be of minor importance in this respect. Reports in the literature demonstrate that cardiac failure may cause malnutrition and that infection/inflammation may predispose to atherosclerosis as well as to catabolism and hypoalbuminemia. Proinflammatory cytokines, generated in response to cardiac failure, infection, and other inflammatory stimuli, appear to play a pivotal role by causing muscle wasting, hypoalbuminemia, and anorexia as well as reduced cardiac contractility and atherosclerotic vascular disease. We hypothesize that this scenario also applies to ESRD patients, in whom congestion, hypertension, cardiac failure, and ischemic cardiovascular disease are common. Malnutrition rarely may be the direct cause of death, except in elderly dialysis patients, but may contribute to a poor prognosis by aggravating pre-existing heart failure and increasing the susceptibility to infections.
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PMID:Malnutrition, cardiac disease, and mortality: an integrated point of view. 982 Apr 57

The aim of rehabilitation is to improve exercise capacity and, thereby, the autonomy of patients with cardiac failure. For many years, these patients were considered inapt to perform physical exercise and they are in the same situation at the dawn of the year 2000 as patients with myocardial infarction forty years ago. The symptoms of cardiac failure (dyspnoea of effort and muscular fatigue) are not only the consequence of pulmonary hypertension and decreased muscular perfusion. Prolonged interruption of exercise and long stays in bed or in a chair lead to anatomical and functional amyotrophy, which, in turns, incites to further inactivity. Deconditioned respiratory muscles cannot tolerate the increased load of hyperventilation. Neurohormonal changes cause vasoconstriction which reduces muscular perfusion. Physical training can significantly improve these abnormalities, though it does not seem to have a measurable effect on cardiac function; based on segmental work which enables performance of substantial efforts with a minimum of haemodynamic changes, it provides a 20 to 30% gain in capacity, mainly increasing the duration of submaximal exercise rather than maximum performance. Muscular fatigue is the symptom which is the most improved. Unfortunately the organisation, which is more difficult than in the post-infarction period, and the generalisation of the practice of long-term, well adapted physical training remains marginal although hundreds of thousands of patients could benefit; more than the inertia of the official instances concerning anything related to cardiac rehabilitation, it is the lack of interest shown by cardiologists and the absence of flexible structures within the health care organisation for elderly people which are responsible.
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PMID:[Rehabilitation by physical exercise in chronic heart failure]. 986 10

Congestive heart failure is characterized by a skeletal muscle myopathy with muscle bulk loss. The mechanisms responsible for these changes are not clear at present. We have investigated the role of apoptosis in the rat "slow" soleus muscle during the development of heart failure, which was induced by injection of monocrotaline (30 mg/kg). We looked at the time course of apoptosis by studying six animals at each of the following time points: 0, 17, 24, and 30 days. We found a decreased expression of the antiapoptotic protein Bcl-2, which was accompanied by a rise of proapoptotic caspase-3. Ubiquitin levels did not change. DNA nick-end labeling showed an increased number of apoptotic nuclei both in myofibers and interstitial cells when heart failure occurred. At variance with previous observations in the fast-twitch tibialis anterior muscle in the same animals, in which tumor necrosis factor-alpha (TNF-alpha) increased at the time that apoptosis occurred, the magnitude of apoptosis is lower in soleus muscle and there is no appearance of muscle atrophy. In soleus muscle, apoptosis is accompanied by activation of the caspase-3 system. There is no activation of the TNF-alpha- and ubiquitin-dependent protein waste. In conclusion, slow muscles are less prone to develop apoptosis than fast muscles. Muscle atrophy appears earlier in these latter ones.
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PMID:Apoptosis and atrophy in rat slow skeletal muscles in chronic heart failure. 1056 91

Malnutrition, inflammation and atherosclerotic cardiovascular disease occur at high prevalence, and often concomitantly, in conjunction with chronic renal failure. Several features of malnutrition (e.g., increased oxidative stress, increased plasma levels of fibrinogen, Lp(a), and inflammation) may all, alone or in concert, increase the risk of cardiovascular disease. Recent findings suggest malnutrition and hypoalbuminaemia in chronic renal failure to be largely the consequence of such factors as heart failure, chronic infection and inflammation, that simultaneously trigger the development of atherosclerotic cardiovascular disease. Central to this scenario is the involvement of proinflammatory cytokines which may cause muscle wasting, hypoalbuminaemia, anorexia, and accelerated atherosclerosis. It is unlikely that the high mortality due to atherosclerotic disease among patients with chronic renal failure can be substantially reduced unless new treatment strategies are developed which address the complex relationships that exist between malnutrition, inflammation and cardiovascular disease.
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PMID:[Strong connection between malnutrition, inflammation and arteriosclerosis. Improved treatment of renal failure if underlying factors are attacked]. 1057 60

Muscle weakness and early fatigue are common symptoms of chronic organ diseases, like chronic obstructive pulmonary disease (COPD), chronic heart failure (CHF) and chronic renal failure (CRF). It is becoming more and more clear that symptom intensities and exercise intolerance are related to muscle wasting and intrinsic alterations in peripheral skeletal muscle in these patient populations, while correlations with parameters of organ functioning are poor. Also, changes in muscle structure and function in COPD, CHF and CRF show much resemblance. Semi-starvation, reduced physical activity and ageing are external factors possibly confounding a direct relationship between the primary organ impairments and alterations in peripheral skeletal muscle and exercise capacity. Reducing the catabolic effects of the various contributing factors might improve muscle function and health status in chronic disease. In this review, we present a systematic overview of human studies on alterations in skeletal muscle function, morphology and energy metabolism in COPD, CHF, CRF and we compare the results with comparable studies in anorexia nervosa, disuse or inactivity and ageing. Unravelling the relative contributions of these external factors to the observed alterations in the various diseases may contribute to targeted intervention strategies to improve muscle function in selected groups of patients.
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PMID:The contribution of starvation, deconditioning and ageing to the observed alterations in peripheral skeletal muscle in chronic organ diseases. 1243 May 63

Nitric oxide (*NO) and its by-products modulate many physiological functions of skeletal muscle including blood flow, metabolism, glucose uptake, and contractile function. However, growing evidence suggests that an overproduction of nitric oxide contributes to muscle wasting in a number of pathologies including chronic heart failure, sepsis, COPD, muscular dystrophy, and extreme disuse. Limited data point to the potential of inhibition various enzymes by reactive nitrogen species (RNS), including (.)NO and its downstream products such as peroxynitrite, primarily in purified systems. We hypothesized that exposure of skeletal muscle to RNS donors would reduce or downregulate activities of the crucial antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX). Diaphragm muscle fiber bundles were extracted from 4-month-old Fischer-344 rats and, in a series of experiments, exposed to either (a) 0 (control), 1, or 5 mM diethylamine NONOate (DEANO: *NO donor); (b) 0, 100, 500 microM, or 1 mM sodium nitroprusside (SNP: *NO donor); (c) 0 or 2 mM S-nitroso-acetylpenicillamine (SNAP: *NO donor); or (d) 0 or 500 microM SIN-1 (peroxynitrite donor) for 60 min. DEANO resulted in a 50% reduction in CAT, GPX, and a dose-dependent inhibition of Cu, Zn-SOD. SNP resulted in significantly lower activities for total SOD, Mn-SOD isoform, Cu, Zn-SOD isoform, CAT, and GPX in a dose-dependent fashion. Two millimolar SNAP and 500 microM SIN-1 also resulted in a large and significant inhibition of total SOD and CAT. These data indicate that reactive nitrogen species impair antioxidant enzyme function in an RNS donor-specific and dose-dependent manner and are consistent with the hypothesis that excess RNS production contributes to skeletal muscle oxidative stress and muscle dysfunction.
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PMID:Specificity of antioxidant enzyme inhibition in skeletal muscle to reactive nitrogen species donors. 1207 89

Heart failure is often characterized by skeletal muscle atrophy. The mechanisms underlying muscle wasting, however, are not fully understood. We studied 30 Dahl salt-sensitive rats (10 male, 20 female) fed either a high-salt (HS; n = 15) or a low-salt (LS; n = 15) diet. This strain develops cardiac hypertrophy and failure when fed a HS diet. LS controls were matched to HS rats for gender and duration of diet. Body mass, food intake, and muscle mass and composition were measured. Skeletal muscle protein synthesis was measured by isotope dilution. An additional group of 27 rats (HS, n = 16; LS; n = 11) were assessed for expression of genes regulating protein breakdown and apoptosis. Gastrocnemius and plantaris muscles weighed less (16 and 22%, respectively) in HS than in LS rats (P < 0.01). No differences in soleus or tibialis anterior weights were found. Differences in muscle mass were abolished after data were expressed relative to body size, because HS rats tended (P = 0.094) to weigh less. Lower body mass in HS rats was related to a 16% reduction (P < 0.01) in food intake. No differences in muscle protein or DNA content, the protein-to-DNA ratio, or muscle protein synthesis were found. Finally, no differences in skeletal muscle gene expression were found to suggest increased protein breakdown or apoptosis in HS rats. Our results suggest that muscle wasting in this model of heart failure is not associated with alterations in skeletal muscle metabolism. Instead, muscle atrophy was related to reduced body weight secondary to decreased food intake. These findings argue against the notion that heart failure is characterized by a skeletal muscle myopathy that predisposes to atrophy.
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PMID:Effect of heart failure on the regulation of skeletal muscle protein synthesis, breakdown, and apoptosis. 1258 12

In many forms of cardiomyopathic left ventricular (LV) dysfunction, there is a rapid myocardial expression of pro-inflammatory cytokines such as interleukin 1, interleukin 6 and tumour necrosis factor-alpha (TNF-alpha) which mediate, via specific receptors, various processes such as gene expression, cell growth or apoptosis. In the initial stages of myocarditis, the myocardial expression of proinflammatory cytokines appears to be part of an inflammatory process. In many other conditions such as ischaemic cardiomyopathy and chronic LV pressure or volume overload, myocardial expression of proinflammatory cytokines is triggered by an elevation of LV wall stress. Myocardial expression of cytokines contributes to depression of contractile performance and adverse LV remodelling. Cytokine-induced depression of contractile performance appears to result from sphingosine production, which interferes with myocardial calcium handling. In transgenic mice, the rate of progression of LV dilatation appears to correlate with the intensity of myocardial TNF-alpha overexpression. In heart failure patients, cytokine concentrations are elevated not only in the myocardium but also in plasma. Cytokines are, therefore, responsible not only for autocrine and paracrine signalling within the myocardium but also for endocrine signalling throughout the body, especially affecting striated muscle mass with induction of muscle wasting and cachexia. The source of cytokine production in heart failure remains uncertain and several mechanisms have been proposed including endotoxin-induced immune activation due to bowel oedema, myocardial production due to haemodynamic overload and peripheral extramyocardial production due to tissue hypoperfusion and hypoxia. The latter seems to be the most likely mechanism, possibly modulated by the presence of bacterial endotoxins released from the gut. Numerous drugs have meanwhile been shown to influence this cardioinflammatory response to heart failure either by reducing basal levels of cytokines (e.g. amlodipine, pentoxifylline, beta-blockers) or by reducing endotoxin-induced cytokine gene expression (e.g. ouabain, amiodarone, adenosine, angiotensin converting enzyme inhibitors, angiotensin II-receptor blockers). Direct blockade of the deleterious actions of elevated plasma levels of cytokines recently became possible through intravenous infusion of a soluble TNF-alpha receptor fusion protein, which resulted in an increase in exercise tolerance and LV performance.
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PMID:Cytokines and heart failure. 1263 74

Elevated levels of proinflammatory cytokines, such as tumor necrosis factor (TNF) and interleukin-6 (IL-6), have been demonstrated in patients with chronic heart failure (CHF). Evidence suggests that cytokines such as these may play a central role in the pathogenesis of this syndrome. TNF has several properties that are particularly detrimental in CHF, such as negatively inotropic effects, the promotion of left ventricular remodelling, and the induction of dilated cardiomyopathy in humans. Furthermore, TNF can cause skeletal muscle wasting and apoptosis, and, therefore, may be important in the development of cardiac cachexia. Although the precise stimulus for immune activation in CHF is unknown, one hypothesis is that endotoxin may be a significant trigger for cytokine release. This is supported by the finding that decompensated CHF patients have elevated endotoxin levels that normalize on diuretic therapy. The factors that influence endotoxin responsiveness in patients with CHF, in particular the potential importance of serum lipoproteins, will be discussed in this review.
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PMID:The importance of tumor necrosis factor and lipoproteins in the pathogenesis of chronic heart failure. 1263 90


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