Syndromes of cardiac cachexia and the cachectic heart: current perspective

Cancer induces cardiomyocyte remodeling and hypoinnervation in the left ventricle of the mouse heart

Cancer is often associated with cachexia, cardiovascular symptoms and autonomic dysregulation. We tested whether extracardiac cancer directly affects the innervation of left ventricular myocardium. Mice injected with Lewis lung carcinoma cells (tumor group, TG) or PBS (control group, CG) were analyzed after 21 days. Cardiac function (echocardiography), serum levels of TNF-α and Il-6 (ELISA), structural alterations of cardiomyocytes and their innervation (design-based stereology) and levels of innervation-related mRNA (quantitative RT-PCR) were analysed. The groups did not differ in various functional parameters. Serum levels of TNF-α and Il-6 were elevated in TG. The total length of axons in the left ventricle was reduced. The number of dense core vesicles per axon profile was reduced. Decreased myofibrillar volume, increased sarcoplasmic volume and increased volume of lipid droplets were indicative of metabolic alterations of TG cardiomyocytes. In the heart, the mRNA level of nerve growth factor was reduced whereas that of β1-adrenergic receptor was unchanged in TG. In the stellate ganglion of TG, mRNA levels of nerve growth factor and neuropeptide Y were decreased and that of tyrosine hydroxylase was increased. In summary, cancer induces a systemic pro-inflammatory state, a significant reduction in myocardial innervation and a catabolic phenotype of cardiomyocytes in the mouse. Reduced expression of nerve growth factor may account for the reduced myocardial innervation.

Body mass index, dementia, and mortality in the elderly

OBJECTIVES

To explore the association between body mass index and mortality in the elderly taking the diagnosis of dementia into account.

DESIGN

Cohort study.

SETTING

cohort study of aging in Medicare recipients in New York City.

PARTICIPANTS

1,452 elderly individuals 65 years and older of both genders.

MEASUREMENTS

We used proportional hazards regression for longitudinal multivariate analyses relating body mass index (BMI) and weight change to all-cause mortality.

RESULTS

There were 479 deaths during 9,974 person-years of follow-up. There were 210 cases of prevalent dementia at baseline, and 209 cases of incident dementia during follow-up. Among 1,372 persons with BMI information, the lowest quartile of BMI was associated with a higher mortality risk compared to the second quartile (HR=1.5; 95% CI: 1.1,2.0) after adjustment for age, gender, education, ethnic group, smoking, cancer, and dementia. When persons with dementia were excluded, both the lowest (HR=1.9; 95% CI=.3,2.6) and highest (HR=1.6; 95% CI: 1.1,2.3) quartiles of BMI were related to higher mortality. Weight loss was related to a higher mortality risk (HR=1.5; 95% CI: 1.2,1.9) but this association was attenuated when persons with short follow-up or persons with dementia were excluded.

CONCLUSION

The presence of dementia does not explain the association between low BMI and higher mortality in the elderly. However, dementia may explain the association between weight loss and higher mortality.

Adiposity and Alzheimer's disease

The objective of this manuscript is to provide a comprehensive review of the relation between adiposity and Alzheimer's disease (AD), its potential mechanisms, and issues in its study. Adiposity represents the body fat tissue content. When the degree of adiposity increases it can be defined as being overweight or obese by measures such as the body mass index. Being overweight or obese is a cause of hyperinsulinemia and diabetes, both of which are risk factors for AD. However, the epidemiologic evidence linking the degree of adiposity and AD is conflicting. Traditional adiposity measures such as body mass index have decreased validity in the elderly. Increased adiposity in early or middle adult life leads to hyperinsulinemia which may lead to diabetes later in life. Thus, the timing of ascertainment of adiposity and its related factors is critical in understanding how it might fit into the pathogenesis of AD. We believe that the most plausible mechanism relating adiposity to AD is hyperinsulinemia, but it is unclear whether specific products of adipose tissue also have a role. Being overweight or obese is increasing in children and adults, thus understanding the association between adiposity and AD has important public health implications.

Treatment of anemia in the patient with heart failure

Anemia is common among patients with chronic heart failure (CHF) and is associated with increased morbidity and mortality. The data suggest that correction of anemia in patients with CHF is beneficial in terms of exercise capacity, New York Heart Association functional class, hospitalization rates, and quality of life. It is not known whether the correction of anemia in this group of patients will improve survival. Small-scale studies in patients with CHF have reported correcting anemia with erythropoietin and oral or intravenous iron. However, the optimal regimen for correction of anemia in patients with CHF has yet to be defined. Significant questions that remain to be answered are the following: which subset of patients with CHF would receive the greatest benefit, when to initiate anemia correction, what dosage of erythropoietin or other agent is appropriate, what target hemoglobin level is to be achieved, and how mortality will be impacted. A cost-benefit analysis is also required. At this point, the treatment of anemia in patients with CHF is not the standard of care and should only be initiated in an investigational setting.

The syndrome of cardiac cachexia

Cachexia, i.e. body wasting, has long been recognised as a serious complication of chronic illness. The occurrence of wasting in chronic heart failure (CHF) has been known for many centuries, but it has not been investigated extensively until recently. Cardiac cachexia is a common complication of CHF which is associated with poor prognosis, independently of functional disease severity, age, measures of exercise capacity, and left ventricular ejection fraction. Patients with cardiac cachexia suffer from generalised loss of lean tissue, fat tissue, as well as bone tissue. Cachectic CHF patients are weaker and fatigue earlier. This is due to both reduced skeletal muscle mass and impaired skeletal muscle quality. Concerning the pathophysiology of cardiac cachexia, there is increasing evidence that neurohormonal and immune abnormalities may play a crucial role. Cachectic CHF patients have raised plasma levels of norepinephrine, epinephrine, and cortisol, and they show high plasma renin activity and increased plasma aldosterone levels. A number of studies have also shown that cardiac cachexia is linked to raised plasma levels of inflammatory cytokines, such as tumor necrosis factor alpha. The available evidence suggests that cardiac cachexia is a multifactorial neuroendocrine and metabolic disorder with a poor prognosis. A complex imbalance of different body systems, termed catabolic/anabolic imbalance, is likely to be responsible for the development of the wasting process. It is hoped that a better understanding of the pathophysiological mechanisms involved in cardiac cachexia will lead to novel therapeutic strategies in the (near) future.

The cardiac component of cardiac cachexia

BACKGROUND

Recent evidence suggests the importance of noncardiac mechanisms in the genesis of the syndrome of cardiac cachexia. This raises the question of the relative role of the heart itself in this syndrome. This study sought to assess the cardiac dimensions, mass, and function and changes in these parameters over time in patients with chronic heart failure with and without cachexia.

METHODS

Doppler echocardiography was performed in 28 patients with nonedematous weight loss (>7.5% over a period of >6 months) compared with 56 matched patients without weight loss in a ratio of 1:2 (age 71 +/- 13 vs 67 +/- 8 years, P =.07; New York Heart Association class 2.9 +/- 0.7 vs 2.6 +/- 0.6, P =.08). In 18 cachectic and 35 noncachectic patients with previous echocardiographic recordings, we analyzed the changes in left ventricular (LV) dimensions and mass over time.

RESULTS

Cardiac dimensions including LV diastolic (69 +/- 9 mm vs 67 +/- 13 mm) and systolic cavity diameter (58 +/- 11 mm vs 55 +/- 15 mm), LV mass (480 +/- 180 g vs 495 +/- 190 g), and LV systolic and diastolic function including fractional shortening (16% +/- 10% vs 18% +/- 10%), isovolumic relaxation time (29 +/- 22 ms vs 36 +/- 27 ms), and E/A ratio (2.7 +/- 1.6 vs 3.3 +/- 2.9) did not differ between cachectic and noncachectic patients (all P >.1). By analyzing changes in LV mass over time, we found an increase (>20%) in 2 (11%) cachectic and 14 (40%) noncachectic patients and a decrease in LV mass (>20%) in 9 (50%) cachectic and 8 (23%) noncachectic patients (chi2 test, P <.05).

CONCLUSIONS

Although no specific cardiac abnormality could be detected echocardiographically in cachectic patients compared with patients with noncachectic chronic heart failure in a cross-sectional study, over time a significant loss of LV mass (>20%) occurs more frequently in patients with cardiac cachexia.

Inappropriately low plasma leptin concentration in the cachexia associated with chronic heart failure

BACKGROUND

Cardiac cachexia is a syndrome of generalised wasting which caries a poor prognosis and is associated with raised plasma concentrations of tumour necrosis factor alpha (TNFalpha). TNFalpha increases secretion of leptin, a hormone which decreases food intake and increases energy expenditure.

OBJECTIVE

To determine whether an inappropriate increase in plasma leptin concentration contributes to the cachexia of chronic heart failure.

DESIGN

Retrospective case-control study.

SETTING

Tertiary referral cardiology unit.

PATIENTS

110 human subjects comprising 29 cachectic chronic heart failure patients, 22 non-cachectic chronic heart failure patients, 33 patients with ischaemic heart disease but normal ventricular function, and 26 healthy controls.

INTERVENTIONS

Measurement of: body fat content by skinfold thickness (cachectic males < 27%, females < 29%); plasma leptin, TNFalpha, and noradrenaline (norepinephrine); central haemodynamics in chronic heart failure patients at right heart catheterisation.

MAIN OUTCOME MEASURES

Plasma leptin concentration corrected for body fat content, plasma TNFalpha and noradrenaline concentration, and central haemodynamics.

RESULTS

Mean (SEM) plasma leptin concentrations were: 6.2 (0.6) ng/ml (cachectic heart failure), 16.9 (3.6) ng/ml (non-cachectic heart failure), 16.8 (3.0) ng/ml (ischaemic heart disease), and 18.3 (3.5) ng/ml (control) (p < 0.001 for cachectic heart failure v all other groups). Plasma leptin concentration remained significantly lower in the cachectic heart failure group even after correcting for body fat content and in spite of significantly increased TNFalpha concentrations. Thus plasma leptin was inappropriately low in cachectic chronic heart failure in the face of a recognised stimulus to its secretion. There was no significant correlation between plasma leptin, New York Heart Association class, ejection fraction, or any haemodynamic indices.

CONCLUSIONS

Leptin does not contribute to the cachexia of chronic heart failure. One or more leptin suppressing mechanisms may operate in this syndrome-for example, the sympathetic nervous system.

Insights into the pathogenesis of chronic heart failure: immune activation and cachexia

Body wasting, i.e, cardiac cachexia, is a complication of chronic heart failure (CHF). The authors have suggested that cardiac cachexia should be diagnosed when nonedematous weight loss of more than 7.5% of the premorbid normal weight occurs over a time period of more than 6 months. In an unselected CHF outpatient population, 16% of patients were found to be cachectic. The cachectic state is predictive of poor survival independently of age, functional class, ejection fraction, and exercise capacity. Patients with cardiac cachexia suffer from a general loss of fat, lean, and bone tissue. Cachectic CHF patients are weaker and fatigue earlier. The pathophysiologic causes of body wasting in patients with CHF remain unclear, but initial studies have suggested that humoral neuroendocrine and immunologic abnormalities may be of importance. Cachectic CHF patients show increased plasma levels of catecholamines, cortisol, and aldosterone. Several studies have shown that cardiac cachexia is linked to increased plasma levels of tumor necrosis factor alpha. The degree of body wasting is strongly correlated with neurohormonal and immune abnormalities. Some investigators have suggested that endotoxin may be important in triggering immune activation in CHF patients. Available studies suggest that cardiac cachexia is a multifactorial neuroendocrine and immunologic disorder that carries a poor prognosis. A complex catabolic-anabolic imbalance in different body systems may cause body wasting in patients with CHF.

Cardiac cachexia: a syndrome with impaired survival and immune and neuroendocrine activation

Chronic heart failure (CHF) is a complex syndrome affecting many body systems. Body wasting (ie, cardiac cachexia) is a serious complication of CHF long known but little investigated. Although no specific diagnostic criteria have been established, we have suggested that cardiac cachexia be defined on the basis of the presence of documented nonintentional and nonedematous weight loss > 7.5% of the premorbid normal weight, occurring over a time period of > 6 months. Using this definition, 16% of an unselected CHF outpatient population was found to be cachectic. The cachectic state is predictive of impaired prognosis independently of age, functional disease classification, left ventricular ejection fraction, and peak oxygen consumption. The mortality in the cachectic cohort is 50% at 18 months. Analyzing body composition in detail, it has been found that patients with cardiac cachexia suffer from a general loss of fat tissue (ie, energy reserves), lean tissue (ie, skeletal muscle), and bone tissue (ie, osteoporosis). Cachectic CHF patients are weaker and fatigue earlier, which is due to both reduced skeletal muscle mass and impaired muscle quality. The pathophysiologic alterations leading to cardiac cachexia remain unclear, but initial cross-sectional studies have suggested that humoral neuroendocrine and immunologic abnormalities are linked, independently of established heart failure severity markers, to the presence of body wasting. Comparing the features of cachectic and noncachectic CHF patients with those of healthy control subjects, it is mainly the cachectic CHF patients who show raised plasma levels of epinephrine, norepinephrine, and cortisol; the highest plasma renin activity and aldosterone plasma concentrations; and the lowest plasma sodium level. Several studies have shown that cardiac cachexia is linked to raised plasma levels of tumor necrosis factor-ac. The degree of body wasting is strongly correlated with neurohormonal and immune abnormalities. The available evidence suggests that cardiac cachexia is a multifactorial neuroendocrine and metabolic disorder with a poor prognosis. A complex imbalance of different body systems may cause the development of body wasting.

Chronic heart failure--mechanisms and management

Over 80% of patients with chronic heart failure are over the age of 65 years. A number of community based studies over the years have indicated that up to half of elderly patients with heart failure are undiagnosed and therefore untreated. The high proportion of elderly patients with heart failure who are undiagnosed is probably due to the non-specific presentation of the condition, heart failure symptoms being over shadowed by co-morbid conditions and the haemodynamic presentation of diastolic dysfunction, vide infra. Measurement of plasma atrial natriuretic peptide levels may be helpful in identifying elderly patients at risk of, or in the early stages of heart failure. Paradoxically, there are also a number of elderly patients who are being treated for heart failure who do not have the condition. Even with the secular changes occurring in lifestyles (smoking, diet, exercise) the prevalence of heart failure will continue to increase well into the next century because of the continuing increase in the number of older people. Difficulties with diagnosis of heart failure may be related to the observation that cardiologists tend to concentrate on young cardiac patients.

Cytokine inhibitors in patients with heart failure and impaired functional capacity

Cytokines are proteins with pleiotropic biological effects, but the pathophysiologic role of cytokine inhibitors in advanced cardiac disease remains unclear. We assessed the levels of tumor necrosis factor (TNF)-alpha and its soluble receptors I (sTNF-RI) and II (sTNF-RII), soluble interleukin-1 receptor antagonist (sIL-1 Ra), and interleukin-6 soluble receptor (IL-6 sR) in sera from 11 patients with severe chronic congestive heart failure (mean left ventricular ejection fraction 19 +/- 6%; mean symptom-limited oxygen consumption 13 +/- 4 ml/min per kg) and 11 healthy volunteers. The serum concentrations of TNF, sTNF-RI, and sIL-1 Ra, but not of sTNF-RII and IL-6 sR, were significantly increased in heart failure patients. Importantly, their symptom-limited oxygen consumption was strongly associated with both sTNF-RI (R = -0.68, p = 0.04) and sIL-1 Ra (R = -0.77, p = 0.01). These results suggest that cytokine inhibitors from different receptor families may be involved in functional disability, a characteristic feature in patients with severe congestive heart failure. Understanding the response of cytokine inhibitors to heart failure might have therapeutic value as interventions against cytokines become available.

Role of cytokines in the mechanism of action of amlodipine: the PRAISE Heart Failure Trial. Prospective Randomized Amlodipine Survival Evaluation

OBJECTIVES

We sought to determine whether the beneficial effects of amlodipine in heart failure may be mediated by a reduction in tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) levels. We postulated that TNF-alpha and IL-6 levels may also have predictive value in patients with congestive heart failure (CHF).

BACKGROUND

The molecular mechanism for progression of CHF may involve cytokine overexpression. The effect of amlodipine on cytokine levels in patients with CHF is unknown.

METHODS

In the Prospective Randomized Amlodipine Survival Evaluation (PRAISE) trial, we used enzyme-linked immunosorbent assay to measure plasma levels of TNF-alpha in 92 patients and IL-6 in 62 patients in New York Heart Association functional classes III and IV randomized to receive amlodipine (10 mg/day) or placebo. Blood samples were obtained for cytokine measurement at baseline and at 8 and 26 weeks after enrollment.

RESULTS

The baseline amlodipine and placebo groups did not differ in demographics and cytokine levels. Mean (+/- SD) plasma levels of TNF-alpha were 5.69 +/- 0.32 pg/ml, and those of IL-6 were 9.23 +/- 1.26 pg/ml at baseline. These levels were elevated 6 and 10 times, respectively, compared with those of normal subjects (p < 0.001). Levels of TNF-alpha did not change significantly over the 26-week period (p = 0.69). However, IL-6 levels were significantly lower at 26 weeks in patients treated with amlodipine versus placebo (p = 0.007 by the Wilcoxon signed-rank test). An adverse event-CHF or death-occurred more commonly in patients with higher IL-6 levels.

CONCLUSIONS

Amlodipine lowers plasma IL-6 levels in patients with CHF. The beneficial effect of amlodipine in CHF may be due to a reduction of cytokines such as IL-6.

Elevated plasma levels of tumor necrosis factor in chronic heart failure with cachexia

To study the potential role of tumor necrosis factor (TNF) in chronic heart failure, we measured the plasma levels of TNF by enzyme linked immunoabsorbent assay in 109 patients with various heart diseases grouped as 'non-heart failure' (n = 36), 'heart failure' (n = 36) and 'cachectic' (n = 37). The daily food intake was also investigated. The results showed that there was no obvious difference of daily caloric intake among the three groups of patients. Plasma levels of TNF were significantly elevated in the patients with 'heart failure' (0.51 +/- 0.26 ng/ml, mean +/- S.E.M.), and even higher in the patients with 'cachexia' (6.19 +/- 2.76 ng/ml), as compared with the patients with 'non-heart failure' (0.09 +/- 0.03 ng/ml). Twenty-five patients with 'cachexia' and 11 patients with 'heart failure' had plasma levels of TNF > or = 100 pg/ml, whereas only 5 patients with 'non-heart failure' had plasma levels of TNF above that level. The patients with high levels of TNF were more cachectic than those with normal levels of TNF (body mass index 19.5 +/- 3.4 vs. 22.3 +/- 3.6, P < 0.05). In multivariate analysis, elevated levels of TNF were associated with the level of serum total protein, presence of heart failure and cachexia. These findings indicate that plasma levels of TNF are increased in patients with heart failure, and high levels of TNF may play an important role in the pathogenesis of cardiac cachexia.

Circulating levels of cytokines and their endogenous modulators in patients with mild to severe congestive heart failure due to coronary artery disease or hypertension

OBJECTIVES

This study sought to determine the circulating levels of cytokines and their respective endogenous modulators in patients with congestive heart failure of variable severity.

BACKGROUND

Activation of immune elements localized in the heart or periphery, or both, may promote release of cytokines in patients with congestive heart failure. Although an increased circulating level of tumor necrosis factor-alpha (TNF-alpha) and its soluble receptor type II (sTNF-RII) is well documented, less is known about other cytokines (i.e., interleukin-1-beta [IL-1-beta], interleukin-6 [IL-6] and interleukin-2 [IL-2] and their soluble receptor/receptor antagonists).

METHODS

Circulating levels of TNF-alpha and sTNF-RII, IL-1-beta, IL-1 receptor antagonist (IL-1-Ra), IL-6, IL-6 soluble receptor (IL-6-sR), IL-2 and IL-2 soluble receptor-alpha were measured using enzyme-linked immunosorbent assay kits (Quantikine, R&D Systems) in 80 patients with congestive heart failure due to coronary artery disease or hypertension. The severity of their symptoms, which ranged from New York Heart Association functional class I to IV, was confirmed by measurement of peak oxygen consumption.

RESULTS

The percentage of patients with elevated levels of cytokines and their corresponding soluble receptor/receptor antagonists significantly increased with functional class. For TNF-alpha and IL-1-beta, the percentage of patients with elevated levels of soluble receptor/receptor antagonists was higher than that of patients with elevated levels of the cytokine itself. For IL-6, the percentage of patients with elevated levels of IL-6-sR tended to be lower than that of patients with elevated levels of IL-6. All but two patients had undetectable levels of IL-2, and all but seven had levels of IL-2-sR within a normal range.

CONCLUSIONS

In patients with congestive heart failure, circulating levels of cytokines increased with the severity of symptoms. In these patients, circulating levels of sTNF-RII and IL-1-Ra are more sensitive markers of immune activation than are circulating levels of TNF-alpha and IL-1-beta, respectively. Levels of IL-2 and IL-2-sR are not elevated when congestive heart failure is due to coronary artery disease or hypertension.

Blood ketone bodies in congestive heart failure

OBJECTIVES

The present study was designed to assess whether blood ketone bodies are elevated in congestive heart failure (CHF) and whether ketonemia is related to the hemodynamic and neurohumoral abnormalities of CHF.

BACKGROUND

In CHF, consumption of the body's fat stores may become abnormally high, contributing to the development of cardiac cachexia. Increased mobilization of free fatty acids could, in theory, augment ketogenesis, but whether patients with CHF are prone to ketosis remains unknown.

METHODS

Forty-five patients with chronic CHF (mean age [+/- SD] 57 +/- 13 years) and 14 control subjects free of CHF (mean age 53 +/- 13 years) underwent invasive and noninvasive cardiac studies and determination of blood ketone bodies (acetoacetate plus beta-hydroxybutyrate), circulating free fatty acids, glucose, lactate, insulin, glucagon, growth hormone, cortisol, norepinephrine, N-terminal proatrial natriuretic peptide, tumor necrosis factor-alpha and interleukin-6 after an overnight fast.

RESULTS

Patients with CHF had elevated blood ketone bodies (median 267 mumol/liter, range 44 to 952) compared with control subjects (median 150 mumol/liter, range 31 to 299, p < 0.05). In the total study group, blood ketone bodies were related to pulmonary artery wedge pressure (r5 = 0.45, p < 0.001), left ventricular ejection fraction (r3 = -0.37, p < 0.01), right atrial pressure (r3 = 0.36, p < 0.01) and circulating concentrations of free fatty acids (r5 = 0.52, p < 0.001), glucose (r5 = -0.39, p < 0.001), norepinephrine (r3 = 0.45, p < 0.001), growth hormone (r5 = 0.30, p < 0.05) and interleukin-6 (r3 = 0.27, p < 0.05). In multivariate analysis, left ventricular ejection fraction, serum free fatty acids and serum glucose were independent predictors of ketonemia.

CONCLUSIONS

Blood ketone bodies are elevated in CHF in proportion to the severity of cardiac dysfunction and neurohormonal activation. This may be at least partly attributable to increased free fatty acid mobilization in response to augmented neurohormonal stimulation. Additional studies are needed to identify the detailed mechanisms and clinical implications of CHF ketosis.

Energy expenditure and symptom severity in men with heart failure

Our results demonstrate a graded increase in resting metabolic rate based on symptom severity as reflected in the New York Heart Association classification. This finding supports the hypothesis that clinical severity of illness corresponds to the magnitude of the increase in resting energy demands.

Indirect calorimetry in critically ill patients: role of the clinical dietitian in interpreting results

Evaluation and interpretation of energy needs of critically ill patients require the expertise of clinical dietitians: Dietitians must be knowledgeable about the methods available to quantify energy needs and able to communicate effectively with physicians and nurses regarding nutritional requirements. Several prediction equations are available for calculating energy needs of critically ill patients. Indirect calorimetry is also used frequently to measure energy requirements in this patient population. This article defines when energy expenditure measured by indirect calorimetry may provide clinically useful information. Data obtained by indirect calorimetry must be interpreted carefully. Indirect calorimetry is based on the equations for oxidation of carbohydrate, protein, and fat. Errors in interpretation can be made when metabolic pathways other than oxidation dominate or when clinical conditions exist that affect carbon dioxide excretion from the lungs. Before incorporating data obtained from indirect calorimetry into a nutrition care plan, the clinical dietitian should carefully evaluate the following factors for a patient: clinical conditions when the measurement was made, desired weight loss or gain, tolerance to food or nutrition support, relationship between protein intake and energy need, and need for anabolism or growth. This article provides clinical examples illustrating how measured values compare with calculated values and recommendations for how to incorporate measured values into nutrition care plans.

Tumor necrosis factor soluble receptors in patients with various degrees of congestive heart failure

BACKGROUND

Tumor necrosis factor alpha (TNF-alpha) increases in patients with severe congestive heart failure (CHF) and cachexia. Two naturally occurring modulators of TNF-alpha activity have been identified in human serum. These two soluble proteins are the extracellular domains of the TNF receptors (sTNF-RI and sTNF-RII, respectively). The determination of circulating sTNF-Rs could provide us with some additional information about the activation of this cytokine in CHF.

METHODS AND RESULTS

This study was undertaken to examine the concentration of sTNF-Rs and of bioactive and antigenic TNF-alpha in 37 consecutive patients with various degrees of CHF compared with that of 26 age-matched healthy subjects. Antigenic TNF-alpha increased (from 14.3 +/- 7.08 to 33.5 +/- 13.1 pg/mL, P < .001) in preterminal patients with severe CHF (New York Heart Association [NYHA] class IV). In these patients, sTNF-Rs were also increased (sTNF-RI from 1.17 +/- 0.43 to 4.43 +/- 2.14 ng/mL and sTNF-RII from 2.2 +/- 0.44 to 7.55 +/- 2.28 ng/mL, P < .001). When measured by cytolytic bioassay, TNF-alpha was undetectable (< 100 pg/mL). Addition of 625 pg/mL recombinant human TNF-alpha (rhTNF-alpha), corresponding in the bioassay to 60% of the lethal dose, to the serum of healthy subjects resulted in a significant increase of the expected cytotoxicity (from 625 to 1290 +/- 411 pg/mL, P < .001). Addition of the same dose of rhTNF-alpha to the serum of patients with mild to moderate CHF (NYHA classes II and III) increased the cytotoxicity from 625 to 877 +/- 132 pg/mL, P < .001. In 4 patients with severe CHF (class IV), the expected cytotoxicity was completely inhibited, whereas it was reduced from 625 to 263 +/- 198 pg/mL, P < .001, in the remaining 8 patients. Ten patients died within 1 month of entry into the study. They had the highest level of sTNF-RII (8.18 +/- 1.92 ng/mL). sTNF-RII was a more powerful independent indicator of mortality than TNF-alpha, sTNF-RI, NYHA class, norepinephrine, and atrial natriuretic peptide.

CONCLUSIONS

Measurement of sTNF-Rs, in addition to antigenic and bioactive TNF-alpha, is essential for evaluation of the activation of this cytokine in CHF. Both sTNF-Rs increase in preterminal patients with severe CHF and might inhibit the in vitro cytotoxicity of TNF-alpha. Antigenic TNF-alpha also increases in severe CHF. The increased levels of sTNF-RII independently correlate with poor short-term prognosis.

Cardiac cachexia: preoperative and postoperative nutrition management

The present study examined the hemodynamic and metabolic effects of nutrition support in patients with malnutrition secondary to severe mitral valve disease and congestive heart failure. Pulmonary artery pressure measurements, echocardiographic studies, gas exchange measurements, immune function tests, and clinical evaluations were made on hospitalized patients 2 weeks before and 3 weeks after surgery for valve replacement or annuloplasty. All patients received a total daily energy intake of 20 to 30 kcal/kg, four of the patients preoperatively as a combination of oral food plus parenteral nutrition and these four patients plus two additional patients as only parenteral nutrition in the early postoperative period. All six patients received nutrition support as oral food plus parenteral nutrition in the late postoperative period. Compared with baseline, nutrition support was associated with stable hemodynamic function, unchanged whole-body oxygen consumption and carbon dioxide production, and improved clinical indices both before and after surgery. Comprehensive hemodynamic, metabolic, and clinical studies thus indicate that acceptable levels of nutrition support can be provided to malnourished patients with severe congestive heart failure, which improves their clinical status and does not adversely influence cardiac function.

Contribution of skeletal muscle atrophy to exercise intolerance and altered muscle metabolism in heart failure

BACKGROUND

The purpose of this study was to investigate the prevalence of skeletal muscle atrophy and its relation to exercise intolerance and abnormal muscle metabolism in patients with heart failure (HF).

METHODS AND RESULTS

Peak VO2, percent ideal body weight (% IBW), 24-hour urine creatinine (Cr), and anthropometrics were measured in 62 ambulatory patients with HF. 31P magnetic resonance spectroscopy (MRS) and imaging (MRI) of the calf were performed in 15 patients with HF and 10 control subjects. Inorganic phosphorus (Pi), phosphocreatine (PCr), and intracellular pH were measured at rest and during exercise. Calf muscle volume was determined from the sum of the integrated area of muscle in 1-cm-thick contiguous axial images from the patella to the calcaneus. A reduced skeletal muscle mass was noted in 68% of patients, as evidenced by a decrease in Cr-to-height ratio of less than 7.4 mg/cm and/or upper arm circumference of less than 5% of normal. Calf muscle volume (MRI) was also reduced in the patients with HF (controls, 675 +/- 84 cm3/m2; HF, 567 +/- 112 cm3/m2; p less than 0.05). Fat stores were largely preserved with triceps skinfold of less than 5% of normal and/or IBW of less than 80% in only 8% of patients. Modest linear correlations were observed between peak VO2 and both calf muscle volume per meter squared (r = 0.48) and midarm muscle area (r = 0.36) (both p less than 0.05). 31P metabolic abnormalities during exercise were observed in the patients with HF, which is consistent with intrinsic oxidative abnormalities. The metabolic changes were weakly correlated with muscle volume (r = -0.42, p less than 0.05).

CONCLUSIONS

These findings indicate that patients with chronic HF frequently develop significant skeletal muscle atrophy and metabolic abnormalities. Atrophy contributes modestly to both the reduced exercise capacity and altered muscle metabolism.

Increased concentrations of tumour necrosis factor in "cachectic" patients with severe chronic heart failure

OBJECTIVE

To ascertain whether patients with cardiac failure and reduced body weight ("cardiac cachexia") have increased circulating concentrations of tumour necrosis factor (cachectin).

DESIGN

Patients with cardiac failure were prospectively identified as "cachectic" (body fat less than 27% in men and less than 29% in women measured by skinfold thickness callipers) or "non-cachectic". Tumour necrosis factor was assayed blind to patient group.

SETTING

Cardiology unit in a tertiary referral centre.

PATIENTS

26 consecutive patients (10 women) (mean age 61) admitted for investigation or treatment of chronic heart failure. All were in New York Heart Association class III or IV.

RESULTS

In nine of the 16 cachectic patients the concentration of tumour necrosis factor was increased (mean (SEM) 74 (20) pg/ml) compared with one of the 10 "non-cachectic" patients (22 pg/ml, p less than 0.001). Patients with a raised circulating concentration of tumour necrosis factor weighed significantly less (55.6 (3.5) kg) than those in whom the concentration of tumour necrosis factor was normal (69.0 (4.1) kg) (p = 0.02).

CONCLUSIONS

Circulating concentrations of tumour necrosis factor were increased in a significant proportion of patients with chronic heart failure and low body weight. Tumour necrosis factor stimulates catabolism experimentally and it may be a factor in the weight loss seen in patients with "cardiac cachexia".