The need for a standardized definition for cachexia in chronic illness

Risk Factors for Heart Failure and Coronary Artery Disease Mortality Based on the National Vital Statistics During a 25-Year Follow-up in Japan - NIPPON DATA90

BACKGROUND

Prevention of heart failure (HF) is a public health issue. Using the National Vital Statistics, we explored risk factors for HF and coronary artery disease (CAD) mortality.

METHODS AND RESULTS

Altogether, 7,556 Japanese individuals aged ≥30 years in 1990 were followed over 25 years; of these, 139 and 154 died from HF and CAD, respectively. In multivariable Cox proportional hazard analysis, common risk factors for CAD and HF mortality were hypertension (hazard ratio [HR] 1.48 [95% confidence interval {CI} 1.00-2.20] and 2.31 [95% CI 1.48-3.61], respectively), diabetes (HR 2.52 [95% CI 1.63-3.90] and 2.07 [95% CI 1.23-3.50], respectively), and current smoking (HR 2.05 [95% CI 1.27-3.31) and 1.86 [95% CI 1.10-3.15], respectively). Specific risk factors for CAD were male sex, chronic kidney disease, history of cardiovascular disease, and both abnormal T and Q waves, with HRs (95% CIs) of 1.75 (1.05-2.92), 1.78 (1.19-2.66), 2.50 (1.62-3.88), and 11.4 (3.64-36.0), respectively. Specific factors for HF were current drinking (HR 0.43; 95% CI 0.24-0.78) and non-high-density lipoprotein cholesterol (non-HDL-C; HR 0.81; 95% CI 0.67-0.98). There was an inverse association between non-HDL-C and HF in those aged ≥65 years (HR 0.71; 95% CI 0.56-0.90), but not in those aged <65 years.

CONCLUSIONS

We identified common risk factors for HF and CAD deaths; a history of cardiovascular disease was a specific risk for CAD.

Malnutrition in cancer patients: Causes, consequences and treatment options

Cancer patients are at a high risk of malnutrition and disease-associated catabolic derangements. It is important to differentiate between 'simple' - voluntary or involuntary - caloric restriction with protein-sparing ketogenic metabolic adaptation and cachexia, characterized by the combination of weight loss and dysmetabolism, most prominently systemic inflammation. While both conditions result in the sacrifice of fat and protein stores and thus impact on treatment tolerance, complication rates and survival, the presence of metabolic derangements is especially dangerous by straining multiple organ functions. To avoid underdiagnosing and undertreating malnutrition, all cancer patients should be routinely screened for nutritional risk. At-risk patients require comprehensive assessment for contributing and treatable causes and, if available, multi-professional efforts to improve food intake, support anabolism, alleviate distress and antagonize pro-inflammatory processes. In curative settings, anabolic support should accompany or even precede anticancer treatments. Prehabilitation before major surgery, has been studied extensively, including muscle training as well as nutritional and/or psychological support. Recent meta-analyses report a consistent benefit on functional capacity and possible improvement in postoperative complications and length of hospital stay. In palliative settings, prevailing catabolic derangements require careful assessment of the individual constellation of disturbed functions and an empathic evaluation of benefits and risks of nutritional interventions. This is of special relevance in patients with an expected survival of less than a few months. Due to the complex interactions of mechanical, metabolic and psychological factors, multi-professional teams should be involved.

Interconnection between Cardiac Cachexia and Heart Failure—Protective Role of Cardiac Obesity

Cachexia may be caused by congestive heart failure, and it is then called cardiac cachexia, which leads to increased morbidity and mortality. Cardiac cachexia also worsens skeletal muscle degradation. Cardiac cachexia is the loss of edema-free muscle mass with or without affecting fat tissue. It is mainly caused by a loss of balance between protein synthesis and degradation, or it may result from intestinal malabsorption. The loss of balance in protein synthesis and degradation may be the consequence of altered endocrine mediators such as insulin, insulin-like growth factor 1, leptin, ghrelin, melanocortin, growth hormone and neuropeptide Y. In contrast to many other health problems, fat accumulation in the heart is protective in this condition. Fat in the heart can be divided into epicardial, myocardial and cardiac steatosis. In this review, we describe and discuss these topics, pointing out the interconnection between heart failure and cardiac cachexia and the protective role of cardiac obesity. We also set the basis for possible screening methods that may allow for a timely diagnosis of cardiac cachexia, since there is still no cure for this condition. Several therapeutic procedures are discussed including exercise, nutritional proposals, myostatin antibodies, ghrelin, anabolic steroids, anti-inflammatory substances, beta-adrenergic agonists, medroxyprogesterone acetate, megestrol acetate, cannabinoids, statins, thalidomide, proteasome inhibitors and pentoxifylline. However, to this date, there is no cure for cachexia.

Mathematical Model of Muscle Wasting in Cancer Cachexia

Cancer cachexia is a debilitating condition characterized by an extreme loss of skeletal muscle mass, which negatively impacts patients' quality of life, reduces their ability to sustain anti-cancer therapies, and increases the risk of mortality. Recent discoveries have identified the myostatin/activin A/ActRIIB pathway as critical to muscle wasting by inducing satellite cell quiescence and increasing muscle-specific ubiquitin ligases responsible for atrophy. Remarkably, pharmacological blockade of the ActRIIB pathway has been shown to reverse muscle wasting and prolong the survival time of tumor-bearing animals. To explore the implications of this signaling pathway and potential therapeutic targets in cachexia, we construct a novel mathematical model of muscle tissue subjected to tumor-derived cachectic factors. The model formulation tracks the intercellular interactions between cancer cell, satellite cell, and muscle cell populations. The model is parameterized by fitting to colon-26 mouse model data, and the analysis provides insight into tissue growth in healthy, cancerous, and post-cachexia treatment conditions. Model predictions suggest that cachexia fundamentally alters muscle tissue health, as measured by the stem cell ratio, and this is only partially recovered by anti-cachexia treatment. Our mathematical findings suggest that after blocking the myostatin/activin A pathway, partial recovery of cancer-induced muscle loss requires the activation and proliferation of the satellite cell compartment with a functional differentiation program.

Plasma Lipid Profile and Systemic Inflammation in Patients With Cancer Cachexia

Cancer cachexia affects about 80% of advanced cancer patients, it is linked to poor prognosis and to date, there is no efficient treatment or cure. The syndrome leads to progressive involuntary loss of muscle and fat mass induced by systemic inflammatory processes. The role of the white adipose tissue (WAT) in the onset and manifestation of cancer cachexia gained importance during the last decade. WAT wasting is not only characterized by increased lipolysis and release of free fatty acids (FFA), but in addition, owing to its high capacity to produce a variety of inflammatory factors. The aim of this study was to characterize plasma lipid profile of cachectic patients and to correlate the FA composition with circulating inflammatory markers; finally, we sought to establish whether the fatty acids released by adipocytes trigger and/or contribute to local and systemic inflammation in cachexia. The study selected 65 patients further divided into 3 groups: control (N); weight stable cancer (WSC); and cachectic cancer (CC). The plasma FA profile was significantly different among the groups and was positively correlated with pro-inflammatory cytokines expression in the CC patients. Therefore, we propose that saturated to unsaturated FFA ratio may serve as a means of detecting cachexia.

Muscle wasting and cachexia in heart failure: mechanisms and therapies

Body wasting is a serious complication that affects a large proportion of patients with heart failure. Muscle wasting, also known as sarcopenia, is the loss of muscle mass and strength, whereas cachexia describes loss of weight. After reaching guideline-recommended doses of heart failure therapies, the most promising approach to treating body wasting seems to be combined therapy that includes exercise, nutritional counselling, and drug treatment. Nutritional considerations include avoiding excessive salt and fluid intake, and replenishment of deficiencies in trace elements. Administration of omega-3 polyunsaturated fatty acids is beneficial in selected patients. High-calorific nutritional supplements can also be useful. The prescription of aerobic exercise training that provokes mild or moderate breathlessness has good scientific support. Drugs with potential benefit in the treatment of body wasting that have been tested in clinical studies in patients with heart failure include testosterone, ghrelin, recombinant human growth hormone, essential amino acids, and β₂-adrenergic receptor agonists. In this Review, we summarize the pathophysiological mechanisms of muscle wasting and cachexia in heart failure, and highlight the potential treatment strategies. We aim to provide clinicians with the relevant information on body wasting to understand and treat these conditions in patients with heart failure.

Differentiating Sarcopenia and Cachexia Among Patients With Cancer

Patients with cancer are at an increased risk for muscle loss via 2 distinct mechanisms: sarcopenia, defined as the age-associated decrease in muscle mass related to changes in muscle synthesis signaling pathways, and/or cachexia, defined as cytokine-mediated degradation of muscle and adipose depots. Both wasting disorders are prevalent; among patients with cancer, 15%-50% are sarcopenic and 25%-80% are cachectic. Muscle mass may be difficult to quantify in overweight/obese individuals. Often, overweight/obese patients with cancer are assumed to be normally nourished when in fact severe muscle depletion may be present. No universally accepted treatment exists for preventing or reversing sarcopenia or cachexia in patients with cancer. Current treatment options are limited to nutrition therapy and exercise, which may lead to difficulties in adherence during cancer treatment. Future treatments may provide pharmaceutical therapy that targets muscle degradation and synthesis pathways. There is a need to determine a multimodal treatment plan for muscle depletion to improve quality of life, survival, and therapy complications in patients with cancer.

Nutritional Risk Index predicts mortality in hospitalized advanced heart failure patients

BACKGROUND

Hospitalized advanced heart failure (HF) patients are at high risk for malnutrition and death. The Nutritional Risk Index (NRI) is a simple, well-validated tool for identifying patients at risk for nutrition-related complications. We hypothesized that, in advanced HF patients from the ESCAPE (Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness) trial, the NRI would improve risk discrimination for 6-month all-cause mortality.

METHODS

We analyzed the 160 ESCAPE index admission survivors with complete follow-up and NRI data, calculated as follows: NRI = (1.519 × discharge serum albumin [in g/dl]) + (41.7 × discharge weight [in kg] / ideal body weight [in kg]); as in previous studies, if discharge weight is greater than ideal body weight (IBW), this ratio was set to 1. The previously developed ESCAPE mortality model includes: age; 6-minute walk distance; cardiopulmonary resuscitation/mechanical ventilation; discharge β-blocker prescription and diuretic dose; and discharge serum sodium, blood urea nitrogen and brain natriuretic peptide levels. We used Cox proportional hazards modeling for the outcome of 6-month all-cause mortality.

RESULTS

Thirty of 160 patients died within 6 months of hospital discharge. The median NRI was 96 (IQR 91 to 102), reflecting mild-to-moderate nutritional risk. The NRI independently predicted 6-month mortality, with adjusted HR 0.60 (95% CI 0.39 to 0.93, p = 0.02) per 10 units, and increased Harrell's c-index from 0.74 to 0.76 when added to the ESCAPE model. Body mass index and NRI at hospital admission did not predict 6-month mortality. The discharge NRI was most helpful in patients with high (≥ 20%) predicted mortality by the ESCAPE model, where observed 6-month mortality was 38% in patients with NRI < 100 and 14% in those with NRI > 100 (p = 0.04).

CONCLUSIONS

The NRI is a simple tool that can improve mortality risk stratification at hospital discharge in hospitalized patients with advanced HF.

Cancer cachexia, mechanism and treatment

It is estimated that half of all patients with cancer eventually develop a syndrome of cachexia, with anorexia and a progressive loss of adipose tissue and skeletal muscle mass. Cancer cachexia is characterized by systemic inflammation, negative protein and energy balance, and an involuntary loss of lean body mass. It is an insidious syndrome that not only has a dramatic impact on patient quality of life, but also is associated with poor responses to chemotherapy and decreased survival. Cachexia is still largely an underestimated and untreated condition, despite the fact that multiple mechanisms are reported to be involved in its development, with a number of cytokines postulated to play a role in the etiology of the persistent catabolic state. Existing therapies for cachexia, including orexigenic appetite stimulants, focus on palliation of symptoms and reduction of the distress of patients and families rather than prolongation of life. Recent therapies for the cachectic syndrome involve a multidisciplinary approach. Combination therapy with diet modification and/or exercise has been added to novel pharmaceutical agents, such as Megestrol acetate, medroxyprogesterone, ghrelin, omega-3-fatty acid among others. These agents are reported to have improved survival rates as well as quality of life. In this review, we will discuss the emerging understanding of the mechanisms of cancer cachexia, the current treatment options including multidisciplinary combination therapies, as well an update on new and ongoing clinical trials.

Cancer cachexia: impact, mechanisms and emerging treatments

Many forms of cancer present with a complex metabolic profile characterised by loss of lean body mass known as cancer cachexia. The physical impact of cachexia contributes to decreased patient quality of life, treatment success and survival due to gross alterations in protein metabolism, increased oxidative stress and systemic inflammation. The psychological impact also contributes to decreased quality of life for both patients and their families. Combination therapies that target multiple pathways, such as eicosapentaenoic acid administered in combination with exercise, appetite stimulants, antioxidants or anti-inflammatories, have potential in the treatment of this complex syndrome and require further development.

Mechanism and novel therapeutic approaches to wasting in chronic disease

Cachexia is a multifactorial syndrome defined by continuous loss of skeletal muscle mass - with or without loss of fat mass - which cannot be fully reversed by conventional nutritional support and which may lead to progressive functional impairment and increased death risk. Its pathophysiology is characterized by negative protein and energy balance driven by a variable combination of reduced food intake and abnormal metabolism. Muscle wasting is encountered in virtually all chronic disease states in particular during advanced stages of the respective illness. Several pre-clinical and clinical studies are ongoing to ameliorate this clinical problem. The mechanisms of muscle wasting and cachexia in chronic diseases such as cancer, chronic heart failure, chronic obstructive pulmonary disease and chronic kidney disease are described. We discuss therapeutic targets and such potential modulators as appetite stimulants, selective androgen receptor modulators, amino acids and naturally occurring peptide hormones.

The underestimated impact of cachexia

This editorial contains views on the importance of animal research in the field of cachexia, a crippling syndrome associated with almost all chronic diseases that dramatically impact on quality of life and survival of the patient. Unfortunately, it is infrequently identified or diagnosed and too rarely treated. Even if treated, the treatment options are extremely limited, as no truly successful therapies have been established so far. Therefore, research in animal models is of outmost importance, but care should be taken in designing these pre-clinical studies. We propose a design as close to clinical trials as possibly and to use primary endpoints that are of clinical relevance.

The cachexia score (CASCO): a new tool for staging cachectic cancer patients

BACKGROUND: According to a recent consensus, the cachectic syndrome is defined as: "… a complex metabolic syndrome associated with underlying illness and characterized by loss of muscle with or without loss of fat mass. The prominent clinical feature of cachexia is weight loss in adults (corrected for fluid retention) or growth failure in children (excluding endocrine disorders). Anorexia, inflammation, insulin resistance, and increased muscle protein breakdown are frequently associated with cachexia." Although this definition is accompanied by diagnostic criteria, it does not consider the problem of staging. Stratification of patients is important when considering therapy. The very first stage of the wasting syndrome does not necessarily involve body weight loss-a state known as pre-cachexia. METHODS AND RESULTS: The aim of the present score was to overcome the problem of patient staging in cancer. This score considers five main different factors: body weight and lean body mass loss; anorexia; inflammatory, immunological, and metabolic disturbances; physical performance; and quality of life. The scoring scale goes from 0 to 100: mild cachexia (less than 25), moderate (more than 26 and less than 50), severe (more than 51 and less than 75), and terminal phase (more than 76 and up to 100). The score also takes into consideration the condition known as pre-cachexia. CONCLUSION: The present score will facilitate cachexia staging and will therefore allow for a more adequate therapy. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s13539-011-0027-5) contains supplementary material, which is available to authorized users.

Hormonal consequences and prognosis of chronic heart failure

PURPOSE OF REVIEW

Chronic heart failure (CHF) is a major public health problem. The failure to provide peripheral tissues with sufficient amounts of oxygen is accompanied by maladaptive responses that include pathophysiological pathways that may lead to an anabolic-catabolic imbalance with the development of cardiac cachexia. This review aims to highlight players of the catabolic-anabolic imbalance, regulators or appetite, and other mediators that are involved in the progression of CHF to cachexia.

RECENT FINDINGS

Clinical research has buttressed the view that deficiencies or resistance to growth hormone and testosterone plays an important role in the pathophysiology of CHF. The role of appetite regulation in the development of cardiac cachexia is also subject of recent studies. The resistance of CHF patients to the effects of appetite-stimulating peptide ghrelin may be one of the contributing factors. These circumstances drive muscle, bone, and fat wasting. Plasma levels of the adipokines leptin and adiponectin may have a role in the detection of such wasting processes.

SUMMARY

Hormonal signaling pathways play an essential role in the development of cardiac cachexia. Recent findings enhance our understanding of the complex interplay between these regulators and may serve as a hub for the development of therapeutic interventions to prevent or potentially even to treat cardiac cachexia.

Subjective Definitions of Problems and Symptoms in Palliative Care

Background

Data from the core data set of the Hospice and Palliative Care Evaluation (HOPE) from 1999 to 2001 demonstrated considerable variance in the incidence of patients’ symptoms and problems between participating services. This paper aims to investigate these differences more closely.

Methods

During the evaluation period of HOPE in 2002 a telephone survey with a representative of each participating unit was performed. Telephone interviews assessed the professionals’ definitions of selected symptoms and estimates of problem and symptom incidences. Content analysis was used to evaluate qualitative answers.

Results

Staff members rated pain, weakness, nausea/emesis as the most frequent physical symptoms; anxiety, depression and amentia as most frequent psychological symptoms; wound treatment, mobilisation and weakness as nursing problems and organisation of care settings, loneliness, demands of relatives the most common social needs. Staff members used a wide range of definitions for cachexia, weakness and depression.

Discussion

Standard definitions of symptoms and problems were lacking in the articulation of subjective staff members’ perspectives. Meaningful evaluation of multicentre surveys would require training in symptom assessment and classification in order to produce a common basis for documentation. Even though definitions differed widely, underlying concepts seemed to be compatible.

Peak oxygen consumption and long-term all-cause mortality in nonsmall cell lung cancer

BACKGROUND

Identifying strong markers of prognosis is critical to optimize treatment and survival outcomes in patients with nonsmall cell lung cancer (NSCLC). The authors investigated the prognostic significance of preoperative cardiorespiratory fitness (peak oxygen consumption [VO(2peak)]) among operable candidates with NSCLC.

METHODS

By using a prospective design, 398 patients with potentially resectable NSCLC enrolled in Cancer and Leukemia Group B 9238 were recruited between 1993 and 1998. Participants performed a cardiopulmonary exercise test to assess VO(2peak) and were observed until death or June 2008. Cox proportional models were used to estimate the risk of all-cause mortality according to cardiorespiratory fitness category defined by VO(2peak) tertiles (<0.96 of 0.96-1.29/>1.29 L/min⁻¹) with adjustment for age, sex, and performance status.

RESULTS

Median follow-up was 30.8 months; 294 deaths were reported during this period. Compared with patients achieving a VO(2peak) <0.96 L/min⁻¹, the adjusted hazard ratio (HR) for all-cause mortality was 0.64 (95% confidence interval [CI], 0.46-0.88) for a VO(2peak) of 0.96 to 1.29 L/min⁻¹, and 0.56 (95% CI, 0.39-0.80) for a VO(2peak) of >1.29 L/min⁻¹) (P(trend) = .0037). The corresponding HRs for resected patients were 0.66 (95% CI, 0.46-0.95) and 0.59 (95% CI, 0.40-0.89) relative to the lowest VO(2peak) category (P(trend) = .0247), respectively. For nonresected patients, the HRs were 0.78 (95% CI, 0.34-1.79) and 0.39 (95% CI, 0.16-0.94) relative to the lowest category (P(trend) = .0278).

CONCLUSIONS

VO(2peak) is a strong independent predictor of survival in NSCLC that may complement traditional markers of prognosis to improve risk stratification and prognostication.

Cachexia as a major underestimated and unmet medical need: facts and numbers

Cachexia is a serious, however underestimated and underrecognised medical consequence of malignant cancer, chronic heart failure (CHF), chronic kidney disease (CKD), chronic obstructive pulmonary disease (COPD), cystic fibrosis, rheumatoid arthritis, Alzheimer's disease, infectious diseases, and many other chronic illnesses. The prevalence of cachexia is high, ranging from 5% to 15% in CHF or COPD to 60% to 80% in advanced cancer. By population prevalence, the most frequent cachexia subtypes are in order: COPD cachexia, cardiac cachexia (in CHF), cancer cachexia, and CKD cachexia. In industrialized countries (North America, Europe, Japan), the overall prevalence of cachexia (due to any disease) is growing and currently about 1%, i.e., about nine million patients. The relative prevalence of cachexia is somewhat less in Asia, but is a growing problem there as well. In absolute terms, cachexia is, in Asia (due to the larger population), as least as big a problem as in the Western world. Cachexia is also a big medical problem in South America and Africa, but data are scarce. A consensus statement recently proposed to diagnose cachexia in chronic diseases when there is weight loss exceeding 5% within the previous 3-12 months combined with symptoms characteristic for cachexia (e.g., fatigue), loss of skeletal muscle and biochemical abnormalities (e.g., anemia or inflammation). Treatment approaches using anabolics, anti-catabolic therapies, appetite stimulants, and nutritional interventions are under development. A more thorough understanding of the pathophysiology of cachexia development and progression is needed that likely will lead to combination therapies being developed. These efforts are greatly needed as presence of cachexia is always associated with high-mortality and poor-symptom status and dismal quality of life. It is thought that in cancer, more than 30% of patients die due to cachexia and more than 50% of patients with cancer die with cachexia being present. In other chronic illnesses, one can estimate that up to 30% of patients die with some degree of cachexia being present. Mortality rates of patients with cachexia range from 10% to 15% per year (COPD), to 20% to 30% per year (CHF, CKD) to 80% in cancer.

[Percutaneous aortic valve replacement - pro]

Percutaneous aortic valve replacement is presently on its way to revolutionize the current treatment practice for patients with degenerative aortic valve stenosis. Two different techniques are available: the balloon-expandable Edwards valve prosthesis and the self-expanding CoreValve ReValving prosthesis. After an initial learning curve as well as device modifications, use of the current generations has a > 95% success rate with a low peri- and post-interventional complication rate. In this article, an overview on the current status of this technique will be provided.

Estimation of Cachexia among Cancer Patients Based on Four Definitions

Objectives. Estimate and compare the proportion of cancer patients with cachexia using different definitions from available clinical data. Methods. Electronic medical records were examined to estimate the proportion of cancer patients with cachexia using 4 definitions: (1) ICD-9 diagnostic code of 799.4 (cachexia), (2) ICD-9 diagnosis of cachexia, anorexia, abnormal weight loss, or feeding difficulties, (3) prescription for megestrol acetate, oxandrolone, somatropin, or dronabinol, and (4) ≥5% weight loss. Patients with cancer of the stomach, pancreas, lung, colon/rectum, head/neck, esophagus, prostate, breast, or liver diagnosed between 1999 and 2004 were followed for cachexia. Results. Of 8541 cancer patients (60% men and 55% Caucasian), cachexia was observed in 2.4% of patients using the cachexia diagnostic code, 5.5% expanded diagnoses, 6.4% prescription medication definition, and 14.7% with ≥5% weight loss. Conclusions. The proportion of patients with cachexia varied considerably depending upon the definition employed, indicating that a standard operational definition is needed.

Hormonal regulators of appetite

Obesity is a significant cause of morbidity and mortality worldwide. There has been a significant worsening of the obesity epidemic mainly due to alterations in dietary intake and energy expenditure. Alternatively, cachexia, or pathologic weight loss, is a significant problem for individuals with chronic disease. Despite their obvious differences, both processes involve hormones that regulate appetite. These hormones act on specific centers in the brain that affect the sensations of hunger and satiety. Mutations in these hormones or their receptors can cause substantial pathology leading to obesity or anorexia. Identification of individuals with specific genetic mutations may ultimately lead to more appropriate therapies targeted at the underlying disease process. Thus far, these hormones have mainly been studied in adults and animal models. This article is aimed at reviewing the hormones involved in hunger and satiety, with a focus on pediatrics.

Cardiac cachexia: a systematic overview

Cardiac cachexia as a terminal stage of chronic heart failure carries a poor prognosis. The definition of this clinical syndrome has been a matter of debate in recent years. This review describes the ongoing discussion about this issue and the complex pathophysiology of cardiac cachexia and chronic heart failure with particular focus on immunological, metabolic, and hormonal aspects at the intracellular and extracellular level. These include regulators such as neuropeptide Y, leptin, melanocortins, ghrelin, growth hormone, and insulin. The regulation of feeding is discussed as are nutritional aspects in the treatment of the disease. The mechanisms of wasting in different body compartments are described. Moreover, we discuss several therapeutic approaches. These include appetite stimulants like megestrol acetate, medroxyprogesterone acetate, and cannabinoids. Other drug classes of interest comprise angiotensin-converting enzyme inhibitors, beta-blockers, anabolic steroids, beta-adrenergic agonists, anti-inflammatory substances, statins, thalidomide, proteasome inhibitors, and pentoxifylline.

Central mechanisms controlling appetite and food intake in a cancer setting: an update

PURPOSE OF REVIEW

Cachexia, also known as disease-associated wasting, is an important factor in the mortality of many patients with diseases such as cancer, as well as renal and congestive heart failure. Yet the syndrome is not yet well defined, making diagnosis difficult and often subjective on the part of the physician. Nor are the central mechanisms of cachexia fully elucidated. Recent studies have begun to address these gaps by focusing on three areas: the role of cytokines in cachexia, other proteins and peptides that might be involved, and potential treatments for this devastating syndrome.

RECENT FINDINGS

Cachexia can be caused, in the absence of disease, by inflammatory stimuli and some chemotherapy drugs, suggesting possible central mechanisms in cachexia. Promising treatments include melanocortin antagonism and some hormones.

SUMMARY

While more research is necessary to illuminate causal mechanisms and uncover potential therapies of cachexia, several of its major molecular pathways have become elucidated, suggesting directions for therapeutic approaches.

Cachexia: a new definition

On December 13th and 14th a group of scientists and clinicians met in Washington, DC, for the cachexia consensus conference. At the present time, there is no widely agreed upon operational definition of cachexia. The lack of a definition accepted by clinician and researchers has limited identification and treatment of cachectic patient as well as the development and approval of potential therapeutic agents. The definition that emerged is: "cachexia, is a complex metabolic syndrome associated with underlying illness and characterized by loss of muscle with or without loss of fat mass. The prominent clinical feature of cachexia is weight loss in adults (corrected for fluid retention) or growth failure in children (excluding endocrine disorders). Anorexia, inflammation, insulin resistance and increased muscle protein breakdown are frequently associated with cachexia. Cachexia is distinct from starvation, age-related loss of muscle mass, primary depression, malabsorption and hyperthyroidism and is associated with increased morbidity. While this definition has not been tested in epidemiological or intervention studies, a consensus operational definition provides an opportunity for increased research.

Morphometric changes induced by amino acid supplementation in skeletal and cardiac muscles of old mice

Aging is associated with progressive structural disorganization of muscular and cardiac fibers, decreasing functional capacity, and increased rates of disease and death. Aging is also characterized by disturbances in protein synthesis with impaired cellular organelle functions, particularly in the mitochondria. The availability of amino acids is a key factor for the overall metabolism of mammals and exogenous supplements of amino acid mixtures (AAm) could be a valid therapeutic strategy to improve quality of life, avoiding malnutrition and muscle wasting in the elderly. We investigated the morphoquantitative effects of long-term AAm supplementation on the mitochondria and sarcomeres (by electron microscope) and on collagen matrix deposition (by histologic techniques) in both skeletal and cardiac muscles of young and aged mice. Our data showed that old animals have fewer mitochondria and massive fibrosis in both muscles. Long-term AAm supplementation increased the number and volume of mitochondria and sarcomeres and decreased fibrosis in both skeletal muscle and hearts in old rats. These findings indicate that AAm restored muscular morphologic parameters and probably improved the mechanical performance of these organs.

Oral amino acid supplements improve exercise capacities in elderly patients with chronic heart failure

We investigated whether 30 days of oral supplementation with a special mixture of amino acids (AAs), together with conventional therapy, could improve exercise capacity in elderly outpatients with chronic heart failure (CHF). A group of 95 outpatients (12 women and 83 men; New York Heart Association class II-III) aged 65-74 years were studied. This was a randomized, double-blind, placebo-controlled study. The patients performed a basal exercise test and were then randomly assigned to a special oral nutritional mixture of AAs 4 g twice daily (n = 43) or placebo (n = 42). After 30 days we repeated the exercise test. In both tests we measured the following: oxygen consumption (VO2), CO2 production (VCO2), minute ventilation (VE), oxygen cost of ventilation (VO2/VE), CO2 elimination per liter of ventilation (VCO2/VE), respiratory exchange ratio (RER; calculated as VCO2/VO2), oxygen pulse (VO2/heart rate [HR]) and anaerobic metabolism during exercise (ANA-VO2). At day 30, exercise capacity in the AA group had improved (+11 +/- 8 W, p <0.01; +67.5 +/- 44 seconds, p <0.02). This improvement was associated with both reduced circulatory dysfunction and increased peripheral oxygen availability. Indeed, peak VO2 increased by 1.2 +/- 1.1 mL/kg per min (+12.7% +/- 13%; p<0.02) and VO2/HR improved by 1.5 +/- 1.4 mL O2 per heartbeat (p <0.05). ANA-VO2 was reduced by >50% in patients on AAs (from 20.2 +/- 10 mL/kg at day 0 to 10.9 +/- 5 mL/kg at day 30; p <0.02). These variables did not significantly change for patients who received placebo. In conclusion, the study showed that oral AA supplementation, in conjunction with standard pharmacologic therapy, appears to increase exercise capacity by improving circulatory function, muscle oxygen consumption, and aerobic production of energy in elderly outpatients with CHF.

Hypercatabolic syndrome: molecular basis and effects of nutritional supplements with amino acids

Hypercatabolic syndrome (HS) is a biochemical state characterized by increased circulating catabolic hormones (eg, cortisol, catecholamines) and inflammatory cytokines (eg, tumor necrosis factors, interleukin-1beta), and decreased anabolic insulin effects with consequent insulin resistance. The most important metabolic consequence of HS is the skeletal and cardiac muscle protein breakdown that releases amino acids (AAs), which in turn supports indispensable body energy requirements but also reduces skeletal and cardiac physiologic and metabolic functions. HS occurs in many diseases such as diabetes mellitus, chronic heart failure, chronic obstructive pulmonary disease, renal and liver failure, trauma, sepsis, and senescence. All of these conditions have predominant catabolic molecules with significant muscular wasting and metabolic impairment. Macronutrients such as AA supplements, taken together with conventional therapy, may maintain muscular protein metabolism and cell functions.

Cachexia: common, deadly, with an urgent need for precise definition and new therapies

Cachexia--sometimes also referred to as wasting disease, malnutrition, or hypercatabolism--has been described for centuries and has always raised ominous thoughts that "the end is near." The disease is encountered in many malignant and nonmalignant chronic, ultimately fatal, illnesses. Yet, although cachexia is a deadly syndrome, little is known about its pathophysiology, and the debate regarding its definition is ongoing. Thus, the data on epidemiology can be contested, but a few things are certain: Cachexia is associated with exceedingly high mortality once the syndrome has fully developed, irrespective of the definition we apply, and it is associated with weakness, weight loss, muscle wasting, and inflammation. It is not simply an ancillary event, and it may contribute to the death of the patient either through effects on neuroendocrine and immune defense mechanisms or through protein calorie malnutrition. The therapeutic standard of care for cachexia remains undefined to date, with a few exceptions. Among the recognized approaches, exogenous oral amino acid supplementation appears very promising. Further research efforts are needed and they are ongoing.

A proposed nomenclature and diagnostic criteria for protein-energy wasting in acute and chronic kidney disease

The recent research findings concerning syndromes of muscle wasting, malnutrition, and inflammation in individuals with chronic kidney disease (CKD) or acute kidney injury (AKI) have led to a need for new terminology. To address this need, the International Society of Renal Nutrition and Metabolism (ISRNM) convened an expert panel to review and develop standard terminologies and definitions related to wasting, cachexia, malnutrition, and inflammation in CKD and AKI. The ISRNM expert panel recommends the term 'protein-energy wasting' for loss of body protein mass and fuel reserves. 'Kidney disease wasting' refers to the occurrence of protein-energy wasting in CKD or AKI regardless of the cause. Cachexia is a severe form of protein-energy wasting that occurs infrequently in kidney disease. Protein-energy wasting is diagnosed if three characteristics are present (low serum levels of albumin, transthyretin, or cholesterol), reduced body mass (low or reduced body or fat mass or weight loss with reduced intake of protein and energy), and reduced muscle mass (muscle wasting or sarcopenia, reduced mid-arm muscle circumference). The kidney disease wasting is divided into two main categories of CKD- and AKI-associated protein-energy wasting. Measures of chronic inflammation or other developing tests can be useful clues for the existence of protein-energy wasting but do not define protein-energy wasting. Clinical staging and potential treatment strategies for protein-energy wasting are to be developed in the future.

Neutral sphingomyelinase inhibition participates to the benefits of N-acetylcysteine treatment in post-myocardial infarction failing heart rats

Deficiency in cellular thiol tripeptide glutathione (L-gamma glutamyl-cysteinyl-glycine) determines the severity of several chronic and inflammatory human diseases that may be relieved by oral treatment with the glutathione precursor N-acetylcysteine (NAC). Here, we showed that the left ventricle (LV) of human failing heart was depleted in total glutathione by 54%. Similarly, 2-month post-myocardial infarction (MI) rats, with established chronic heart failure (CHF), displayed deficiency in LV glutathione. One-month oral NAC treatment normalized LV glutathione, improved LV contractile function and lessened adverse LV remodelling in 3-month post-MI rats. Biochemical studies at two time-points of NAC treatment, 3 days and 1 month, showed that inhibition of the neutral sphingomyelinase (N-SMase), Bcl-2 depletion and caspase-3 activation, were key, early and lasting events associated with glutathione repletion. Attenuation of oxidative stress, downregulation of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) and its TNF-R1 receptor were significant after 1-month NAC treatment. These data indicate that, besides glutathione deficiency, N-SMase activation is associated with post-MI CHF progression, and that blockade of N-SMase activation participates to post-infarction failing heart recovery achieved by NAC treatment. NAC treatment in post-MI rats is a way to disrupt the vicious sTNF-alpha/TNF-R1/N-SMase cycle.