Therapy of muscle wasting in cancer: what is the future?

The Role of Standardized Phase Angle in the Assessment of Nutritional Status and Clinical Outcomes in Cancer Patients: A Systematic Review of the Literature

Compared with the phase angle (PA), the predictive ability of the standardized phase angle (SPA) in assessing nutritional status and clinical outcomes in cancer patients remains uncertain. This review aimed to assess (1) the relationship between SPA and nutritional status and clinical outcomes (including complications and survival) in cancer patients; (2) the predictive ability of SPA alone and in comparison with the predictive ability of PA; and (3) the cut-off value of SPA in cancer patients. Studies that addressed the relationship of SPA use to nutritional status, complications, and survival in cancer patients were searched and identified from six electronic databases (PubMed, Medline, CINAHL, Embase, Web of Science, and the Cochrane Library). The included studies were considered to meet the following criteria: English studies with original data that reflected the effects of SPA on nutritional status and clinical outcomes (including complications and survival) and reported a cut-off value of SPA in cancer patients aged ≥18. Thirteen studies that included a total of 2787 participants were evaluated. Five studies assessed the relationship between SPA and nutritional status, and four of them reported a positive relationship between SPA and nutritional status in cancer patients, even considering SPA as a predictor. Twelve studies assessed the relationship between SPA and clinical outcomes in cancer patients. Two-thirds of the studies that evaluated complications reported the predictive ability of SPA; 30% of survival studies reported a positive relationship, 40% reported SPA as a predictor, and 30% reported no relationship. The standard cut-off value for SPA has not yet been determined. Data from the selected studies suggest that SPA might be a predictor of nutritional status. Further studies are needed to determine the value of SPA in predicting nutritional status and clinical outcomes in cancer patients.

CT psoas calculations on the prognosis prediction of emergency laparotomy: a single-center, retrospective cohort study in eastern Asian population

Background

Emergency laparotomy (EL) has a high mortality rate. Clinically, frail patients have a poor tolerance for EL. In recent years, sarcopenia has been used as an important indicator of frailty and has received much attention. There have been five different calculation methods of psoas for computed tomography (CT) to measure sarcopenia, but lack of assessment of these calculation methods in Eastern Asian EL patients.

Methods

We conducted a 2-year retrospective cohort study of patients over 18 years of age who underwent EL in our institution. Five CT measurement values (PMI: psoas muscle index, PML3: psoas muscle to L3 vertebral body ratio, PMD: psoas muscle density, TPG: total psoas gauge, PBSA: psoas muscle to body face area ratio) were calculated to define sarcopenia. Patients with sarcopenia defined by the sex-specific lowest quartile of each measurement were compared with the rest of the cohort. The primary outcome was "ideal outcome", defined as: (1) No postoperative complications of Clavien-Dindo Grade ≥ 4; (2) No mortality within 30 days; (3) When discharged, no need for fluid resuscitation and assisted ventilation, semi-liquid diet tolerated, and able to mobilize independently. The second outcome was mortality at 30-days. Multivariate logistic regression and receiver operating characteristic (ROC) analysis were used.

Results

Two hundred and twenty-eight patients underwent EL met the inclusion criteria, 192 (84.2%) patients had an ideal outcome after surgery; 32 (14%) patients died within 30 days. Multivariate analysis showed that, except PMD, each calculation method of psoas was independently related to clinical outcome (ideal outcome: PML3, P < 0.001; PMI, P = 0.001; PMD, P = 0.157; TPG, P = 0.006; PBSA, P < 0.001; mortality at 30-days: PML3, P < 0.001; PMI, P = 0.002; PMD, P = 0.088; TPG, P = 0.002; PBSA, P = 0.001). In ROC analysis, the prediction model containing PML3 had the largest area under the curve (AUC) value (AUC value = 0.922 and 0.920, respectively).

Conclusion

The sarcopenia determined by CT psoas measurements is significantly related to the clinical outcome of EL. The calculation of CT psoas measurement is suitable for application in outcome prediction of EL. In the future, it is necessary to develop a scoring tool that includes sarcopenia to evaluate the risk of EL better.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13017-022-00435-x.

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.

New perspective for nutritional support of cancer patients: Enteral/parenteral nutrition

Cancer and its treatment result in severe biochemical and physiological alterations associated with a deterioration of quality of life (QoL). Cancer-related malnutrition may evolve into cancer cachexia due to complex interactions between pro-inflammatory cytokines and the host metabolism. Depending on the type of cancer treatment (either curative or palliative), the clinical condition of the patient and nutritional status, adequate and patient-tailored nutritional intervention should be prescribed (diet counseling, oral supplementation, enteral or total parenteral nutrition). Nutritional support has been widely advocated as adjunctive therapy for a variety of underlying illnesses, including surgery and medical oncotherapy (radiation or chemotherapy for cancer). Glutamine, n-3 fatty acids and probiotics/prebiotics are therapeutic factors that potentially modulate gastrointestinal toxicity related to cancer treatments. Enteral and parenteral nutrition may help improve patient survival, functional status and QoL, yet the benefits appear to be primarily limited to patients with good functional status and with gastrointestinal disease affecting nutritional intake. Parenteral nutrition offers the possibility of increased or maintenance of the nutrient intake in patients for whom normal food intake is inadequate and for whom enteral nutrition is not feasible, is contraindicated or is not accepted by the patient. This article reviews evidence on issues relevant to enteral and parenteral nutrition in patients with cancer.

Dynapenia and aging: an update

In 2008, we published an article arguing that the age-related loss of muscle strength is only partially explained by the reduction in muscle mass and that other physiologic factors explain muscle weakness in older adults (Clark BC, Manini TM. Sarcopenia =/= dynapenia. J Gerontol A Biol Sci Med Sci. 2008;63:829-834). Accordingly, we proposed that these events (strength and mass loss) be defined independently, leaving the term "sarcopenia" to be used in its original context to describe the age-related loss of muscle mass. We subsequently coined the term "dynapenia" to describe the age-related loss of muscle strength and power. This article will give an update on both the biological and clinical literature on dynapenia-serving to best synthesize this translational topic. Additionally, we propose a working decision algorithm for defining dynapenia. This algorithm is specific to screening for and defining dynapenia using age, presence or absence of risk factors, a grip strength screening, and if warranted a test for knee extension strength. A definition for a single risk factor such as dynapenia will provide information in building a risk profile for the complex etiology of physical disability. As such, this approach mimics the development of risk profiles for cardiovascular disease that include such factors as hypercholesterolemia, hypertension, hyperglycemia, etc. Because of a lack of data, the working decision algorithm remains to be fully developed and evaluated. However, these efforts are expected to provide a specific understanding of the role that dynapenia plays in the loss of physical function and increased risk for disability among older adults.

Pathogenesis of muscle wasting in cancer cachexia: targeted anabolic and anticatabolic therapies

PURPOSE OF REVIEW

Cancer-related muscle loss, or cachexia, is the cause of death for approximately 2 million people worldwide and severely reduces quality of life. The degree of cachexia is inversely correlated with survival time; however, the exact mechanisms behind cancer-induced muscle wasting remain under investigation.

RECENT FINDINGS

Cytokines such as tumor necrosis factor-alpha trigger degradatory pathways through nuclear factor-kappaB signaling that activate the ubiquitin-proteasome system and muscle proteolysis. Androgen treatment has been shown to reduce inflammatory cytokines and even stimulate anti-inflammatory cytokine production. Amino acid supplementation has been shown to induce muscle protein synthesis in ovarian cancer patients.

SUMMARY

Targeted anabolic therapies aimed at preventing or reversing cancer cachexia might involve the combined use of androgens and amino acids working concurrently to enhance muscle protein synthesis and reduce muscle protein breakdown. Additional focused clinical studies are needed to identify muscle-specific targets or biomarkers for defined therapeutic approaches to slow or prevent cancer cachexia. In this review, we summarize the pathogenesis of cancer-related muscle wasting and discuss potential interventions at reversing or preventing cancer-related muscle loss.

Malnutrition and wasting in renal disease

PURPOSE OF REVIEW

Malnutrition and accelerated catabolism frequently complicate chronic kidney disease and end-stage renal disease. This review provides an update on the recent advances in the understanding of the mechanisms underlying protein-energy wasting, both in experimental and human models, and on the currently available therapeutic approaches.

RECENT FINDINGS

Increased levels of circulating cytokines, metabolic acidosis, oxidative stress and insulin resistance all appear to be variably implicated in muscle protein breakdown during end-stage renal disease and dialysis. The individual role of each component in the pathogenesis of chronic kidney disease-related wasting is still unclear, but recent clinical data show a positive relationship between inflammation and muscle protein catabolism as a major contributing factor.

SUMMARY

The basis for appropriate therapeutic approaches to protein-energy wasting in chronic kidney disease and end-stage renal disease relies entirely on the understanding of its pathophysiology. Our knowledge of the pathogenesis of malnutrition and hypercatabolism in renal disease is still limited and mostly based on experimental data, but the currently available evidence suggests that multimodal preventive and therapeutic strategies should be entertained.

ESPEN Guidelines on Parenteral Nutrition: non-surgical oncology

Parenteral nutrition offers the possibility of increasing or ensuring nutrient intake in patients in whom normal food intake is inadequate and enteral nutrition is not feasible, is contraindicated or is not accepted by the patient. These guidelines are intended to provide evidence-based recommendations for the use of parenteral nutrition in cancer patients. They were developed by an interdisciplinary expert group in accordance with accepted standards, are based on the most relevant publications of the last 30 years and share many of the conclusions of the ESPEN guidelines on enteral nutrition in oncology. Under-nutrition and cachexia occur frequently in cancer patients and are indicators of poor prognosis and, per se, responsible for excess morbidity and mortality. Many indications for parenteral nutrition parallel those for enteral nutrition (weight loss or reduction in food intake for more than 7-10 days), but only those who, for whatever reason cannot be fed orally or enterally, are candidates to receive parenteral nutrition. A standard nutritional regimen may be recommended for short-term parenteral nutrition, while in cachectic patients receiving intravenous feeding for several weeks a high fat-to-glucose ratio may be advised because these patients maintain a high capacity to metabolize fats. The limited nutritional response to the parenteral nutrition reflects more the presence of metabolic derangements which are characteristic of the cachexia syndrome (or merely the short duration of the nutritional support) rather than the inadequacy of the nutritional regimen. Perioperative parenteral nutrition is only recommended in malnourished patients if enteral nutrition is not feasible. In non-surgical well-nourished oncologic patients routine parenteral nutrition is not recommended because it has proved to offer no advantage and is associated with increased morbidity. A benefit, however, is reported in patients undergoing hematopoietic stem cell transplantation. Short-term parenteral nutrition is however commonly accepted in patients with acute gastrointestinal complications from chemotherapy and radiotherapy, and long-term (home) parenteral nutrition will sometimes be a life-saving maneuver in patients with sub acute/chronic radiation enteropathy. In incurable cancer patients home parenteral nutrition may be recommended in hypophagic/(sub)obstructed patients (if there is an acceptable performance status) if they are expected to die from starvation/under nutrition prior to tumor spread.

Dietary supplementation with a specific combination of high protein, leucine, and fish oil improves muscle function and daily activity in tumour-bearing cachectic mice

Cancer cachexia is characterised by metabolic alterations leading to loss of adipose tissue and lean body mass and directly compromises physical performance and the quality of life of cancer patients. In a murine cancer cachectic model, the effects of dietary supplementation with a specific combination of high protein, leucine and fish oil on weight loss, muscle function and physical activity were investigated. Male CD2F1 mice, 6–7 weeks old, were divided into body weight-matched groups: (1) control, (2) tumour-bearing, and (3) tumour-bearing receiving experimental diets. Tumours were induced by s.c. inoculation with murine colon adenocarcinoma (C26) cells. Food intake, body mass, tumour size and 24 h-activity were monitored. Then, 20 days after tumour/vehicle inoculation, the animals were killed and muscle function was tested ex vivo. Tumour-bearing mice showed reduced carcass, muscle and fat mass compared with controls. EDL muscle performance and total daily activity were impaired in the tumour-bearing mice. Addition of single nutrients resulted in no or modest effects. However, supplementation of the diet with the all-in combination of high protein, leucine and fish oil significantly reduced loss of carcass, muscle and fat mass (loss in mass 45, 52 and 65% of TB-con, respectively (P<0.02)) and improved muscle performance (loss of max force reduced to 55–64% of TB-con (P<0.05)). Moreover, total daily activity normalised after intervention with the specific nutritional combination (50% of the reduction in activity of TB-con (P<0.05)). In conclusion, a nutritional combination of high protein, leucine and fish oil reduced cachectic symptoms and improved functional performance in cancer cachectic mice. Comparison of the nutritional combination with its individual modules revealed additive effects of the single components provided.

Muscle myostatin signalling is enhanced in experimental cancer cachexia

BACKGROUND/AIMS

Myostatin belongs to the transforming growth factor-beta superfamily and negatively regulates skeletal muscle mass. Its deletion induces muscle overgrowth, while, on the contrary, its overexpression or systemic administration cause muscle atrophy. The present study was aimed at investigating whether muscle depletion as occurring in an experimental model of cancer cachexia, the rat bearing the Yoshida AH-130 hepatoma, is associated with modulations of myostatin signalling and whether the cytokine tumour necrosis factor-alpha may be relevant in this regard.

MATERIALS AND METHODS

Protein levels of myostatin, follistatin (myostatin endogenous inhibitor) and the activin receptor type IIB have been evaluated in the gastrocnemius of tumour-bearing rats by Western blotting. Circulating myostatin and follistatin in tumour hosts were evaluated by immunoprecipitation, while the DNA-binding activity of the SMAD transcription factors was determined by electrophoretic-mobility shift assay.

RESULTS

In day 4 tumour hosts muscle myostatin levels were comparable to controls, yet follistatin was reduced, and SMAD DNA-binding activity was enhanced. At day 7, both myostatin and follistatin increased in tumour bearers, while SMAD DNA-binding activity was unchanged. To investigate whether tumour necrosis factor-alpha contributed to induce such changes, rats were administered pentoxifylline, an inhibitor of tumour necrosis factor-alpha synthesis that partially corrects muscle depletion in tumour-bearing rats. The drug reduced both myostatin expression and SMAD DNA-binding activity in day 4 tumour hosts and up-regulated follistatin at day 7.

CONCLUSIONS

These observations suggest that myostatin pathway should be regarded as a potential therapeutic target in cancer cachexia.

Prevalence and clinical implications of sarcopenic obesity in patients with solid tumours of the respiratory and gastrointestinal tracts: a population-based study

BACKGROUND

Emerging evidence on body composition suggests that sarcopenic obesity (obesity with depleted muscle mass) might be predictive of morbidity and mortality in non-malignant disease and also of toxicity to chemotherapy. We aimed to assess the prevalence and clinical implications of sarcopenic obesity in patients with cancer.

METHODS

Between Jan 13, 2004, and Jan 19, 2007, 2115 patients with solid tumours of the respiratory or gastrointestinal tract from a cancer treatment centre serving northern Alberta, Canada, were identified. Available lumbar CT images of the obese patients were analysed for total skeletal muscle cross-sectional area; these values were also used to estimate total body fat-free mass (FFM).

FINDINGS

Of the 2115 patients initially identified, 325 (15%) were classified as obese (body-mass index [BMI] > or =30). Of these obese patients, 250 had CT images that met the criteria for analysis. The remaining 75 patients were recorded as without assessable scans. Obese patients had a wide range of muscle mass. Sex-specific cut-offs that defined a significant association between low muscle mass with mortality were ascertained by optimum stratification analysis: 38 (15%) of 250 patients who had assessable CT images that met the criteria for analysis were below these cut-offs and were classified as having sarcopenia. Sarcopenic obesity was associated with poorer functional status compared with obese patients who did not have sarcopenia (p=0.009), and was an independent predictor of survival (hazard ratio [HR] 4.2 [95% CI 2.4-7.2], p<0.0001). Estimated FFM showed a poor association with body-surface area (r(2)=0.37). Assuming that FFM represents the volume of distribution of many cytotoxic chemotherapy drugs, we estimated that individual variation in FFM could account for up to three-times variation in effective volume of distribution for chemotherapy administered per unit body-surface area, in this population.

INTERPRETATION

This study provides evidence of the great variability of body composition in patients with cancer and links body composition, especially sarcopenic obesity, to clinical implications such as functional status, survival, and potentially, chemotherapy toxicity.

Conjugated linoleic acid suppresses myogenic gene expression in a model of human muscle cell inflammation

Proinflammatory cytokines, such as tumor necrosis factor (TNF)-alpha, contribute to muscle wasting in inflammatory disorders, where TNFalpha acts to regulate myogenic genes. Conjugated linoleic acid (CLA) has shown promise as an antiproliferative and antiinflammatory agent, leading to its potential as a therapeutic agent in muscle-wasting disorders. To evaluate the effect of CLA on myogenesis during inflammation, human primary muscle cells were grown in culture and exposed to varying concentrations of TNFalpha and the cis-9, trans-11 and trans-10, cis-12 CLA isomers. Expression of myogenic genes (Myf5, MyoD, myogenin, and myostatin) and the functional genes creatine kinase (CK) and myosin heavy chain (MHC IIx) were measured by real-time PCR. TNFalpha significantly downregulated MyoD and myogenin expression, whereas it increased Myf5 expression. These changes corresponded with a decrease in both CK and MHC IIx expression. Both isomers of CLA mimicked the inhibitory effect of TNFalpha treatment on MyoD and myogenin expression, whereas myostatin expression was diminished in the presence of both isomers of CLA either alone or in combination with TNFalpha. Both isomers of CLA decreased CK and MHC IIx expression. These findings demonstrate that TNFalpha can have specific regulatory effects on myogenic genes in primary human muscle cells. A postulated antiinflammatory role of CLA in myogenesis appears more complex, with an indication that CLA may have a negative effect on this process.

Taste intensity and hedonic responses to simple beverages in gastrointestinal cancer patients

Changes in the taste of food have been implicated as a potential cause of reduced dietary intake among cancer patients. However, data on intensity and hedonic responses to the four basic tastes in cancer are scanty and contradictory. The present study aimed at evaluating taste intensity and hedonic responses to simple beverages in 47 anorectic patients affected by gastrointestinal cancer and in 55 healthy subjects. Five suprathreshold concentrations of each of the four test substances (sucrose in black current drinks, citric acid in lemonade, NaCl in unsalted tomato juice, and urea in tonic water) were used. Patients were invited to express a judgment of intensity and pleasantness ranging from 0 to 10. Mean intensity scores directly correlated with concentrations of sour, salty, bitter, and sweet stimuli, in both normals and those with cancer. Intensity judgments were higher in cancer patients with respect to sweet (for median and high concentrations, P<0.05), salty (for all concentrations, P<0.05), and bitter tastes (for median concentration, P<0.01). Hedonic function increased with the increase of the stimuli only for the sweet taste. A negative linear correlation was found between sour, bitter, and salty concentrations and hedonic score. Both in cancer patients and in healthy subjects, hedonic judgments increased with the increase of the stimulus for the sweet taste (r=0.978 and r=0.985, P=0.004 and P=0.002, respectively), and decreased for the salty (r=-0.827 and r=-0.884, P=0.084 and P=0.047, respectively) and bitter tastes (r=-0.990 and r=-0.962, P=0.009 and P=0.001, respectively). For the sour taste, the hedonic scores remained stable with the increase of the stimulus in noncancer controls (r=-0.785, P=0.115) and decreased in cancer patients (r=-0.996, P=0.0001). The hedonic scores for the sweet taste and the bitter taste were similar in cancer patients and healthy subjects, and these scores were significantly higher in cancer patients than in healthy subjects for most of the concentrations of the salty taste and all the concentrations of the sour taste. The present study suggests that cancer patients, compared to healthy individuals, have a normal sensitivity, a normal liking for pleasant stimuli, and a decreased dislike for unpleasant stimuli. Moreover, when compared to controls, they show higher hedonic scores for middle and high concentrations of the salty taste and for all concentrations of the sour taste. Further studies are needed to evaluate whether these changes observed in cancer patients translate into any alteration in dietary behavior and/or food preferences.

Muscle cachexia is regulated by a p53-PW1/Peg3-dependent pathway

Muscle wasting (cachexia) is an incurable complication associated with chronic infection and cancers that leads to an overall poor prognosis for recovery. Tumor necrosis factor-alpha (TNFalpha) is a key inflammatory cytokine associated with cachexia. TNFalpha inhibits myogenic differentiation and skeletal muscle regeneration through downstream effectors of the p53 cell death pathway including PW1/Peg3, bax, and caspases. We report that p53 is required for the TNFalpha-mediated inhibition of myogenesis in vitro and contributes to muscle wasting in response to tumor load in vivo. We further demonstrate that PW1 and p53 participate in a positive feedback regulatory loop in vitro. Consistent with this observation, we find that the number of PW1-expressing stem cells in skeletal muscle declines significantly in p53 nullizygous mice. Furthermore, gene transfer of a dominant-negative form of PW1 into muscle tissue in vivo blocks myofiber atrophy in response to tumor load. Taken together, these results show a novel role for p53 in mediating muscle stem cell behavior and muscle atrophy, and point to new targets for the therapeutic treatment of muscle wasting.

Dexamethasone-induced protein degradation in cultured myotubes is p300/HAT dependent

Muscle proteolysis during sepsis and other catabolic conditions is, at least in part, regulated by glucocorticoids. Dexamethasone-treated myotubes are a commonly used in vitro model of muscle wasting. We reported recently that treatment of cultured L6 myotubes with dexamethasone resulted in increased gene and protein expression of the nuclear cofactor p300 but it is not known whether glucocorticoids upregulate p300 histone acetyl transferase (HAT) activity in muscle and whether p300/HAT activity regulates glucocorticoid-induced muscle proteolysis. Here, we found that treatment of cultured L6 myotubes with dexamethasone resulted in increased nuclear p300/HAT activity. Treatment of myotubes with p300 siRNA or transfection of muscle cells with a plasmid expressing p300 that was mutated in its HAT activity domain blocked the dexamethasone-induced increase in protein degradation, supporting a role of p300/HAT in glucocorticoid-induced muscle proteolysis. In addition to increased HAT activity, treatment of the myotubes with dexamethasone resulted in reduced nuclear expression and activity of histone deacetylases (HDACs) 3 and 6. When myotubes were treated with the HDAC inhibitor trichostatin A, protein degradation increased to the same degree as in dexamethasone-treated myotubes. The results suggest that glucocorticoids increase HAT and decrease HDAC activities in muscle, changes that both favor hyperacetylation. The results also provide evidence that dexamethasone-induced protein degradation in cultured myotubes is, at least in part, regulated by p300/HAT activity.

IGF-1 is downregulated in experimental cancer cachexia

Cancer cachexia is characterized by skeletal muscle wasting that is mainly supported by hypercatabolism. Muscle atrophy has been suggested to depend on impaired IGF-1 signal transduction pathway. The present study has been aimed at investigating the IGF-1 system in rats bearing the AH-130 hepatoma, a well-characterized model of cachexia. IGF-1 mRNA expression in the gastrocnemius of tumor hosts progressively decreases to ∼50% of controls. By contrast, both IGF-1 receptor and insulin receptor mRNA levels increase in day 7 AH-130 hosts. IGF-1 and insulin circulating levels, as well as IGF-1 expression in the liver, are reduced. Muscle wasting in the AH-130 bearers is associated with hyperactivation of the ubiquitin-proteasome system. Consistently, the mRNA levels of ubiquitin and of the ubiquitin ligases atrogin-1 and MuRF1 are significantly increased in the gastrocnemius of day 7 AH-130 hosts. Exogenous IGF-1 administered to tumor bearers does not prevent cachexia. IGF-1 mRNA levels also have been evaluated in the gastrocnemius of AH-130 hosts treated with pentoxifylline, an inhibitor of TNF-α synthesis, alone or combined with formoterol, a β2-adrenergic agonist. Both treatments partially correct muscle atrophy without modifying IGF-1 and atrogin-1 mRNA levels, whereas MuRF1 hyperexpression is reduced by the combination of pentoxifylline with formoterol. These results demonstrate for the first time that the IGF-1 system is downregulated in cancer cachexia, although the underlying mechanism remains unknown. Moreover, no simple relation linking IGF-1 and/or atrogin-1 mRNA levels and muscle atrophy could be observed in these experimental conditions. Further studies are thus needed to clarify both issues.

ESPEN Guidelines on Enteral Nutrition: Non-surgical oncology

Enteral nutrition (EN) by means of oral nutritional supplements (ONS) and tube feeding (TF) offers the possibility of increasing or ensuring nutrient intake in cases where normal food intake is inadequate. These guidelines are intended to give evidence-based recommendations for the use of ONS and TF in cancer patients. They were developed by an interdisciplinary expert group in accordance with officially accepted standards, are based on all relevant publications since 1985 and were discussed and accepted in a consensus conference. Undernutrition and cachexia occur frequently in cancer patients and are indicators of poor prognosis. EN should be started if undernutrition already exists or if food intake is markedly reduced for more than 7-10 days. Standard formulae are recommended for EN. Nutritional needs generally are comparable to non-cancer subjects. In cachectic patients metabolic modulators such as progestins, steroids and possibly eicosapentaenoic acid may help to improve nutritional status. EN is indicated preoperatively for 5-7 days in cancer patients undergoing major abdominal surgery. During radiotherapy of head/neck and gastrointestinal regions dietary counselling and ONS prevent weight loss and interruption of radiotherapy. Routine EN is not indicated during (high-dose) chemotherapy.

Treatment of unintentional weight loss in patients with cancer

Malnutrition from anorexia and reduced nutrient intake is common in patients with cancer. Abnormalities in gastrointestinal function caused by the tumor or treatment of the tumor may be direct causes for nutrition challenges. However, other patients may present with cancer cachexia, a wasting syndrome characterized by weight loss, anorexia, early satiety, progressive debilitation, and malnutrition that results in a greater risk of organ dysfunction and death. Changes in host metabolism and energy expenditure are thought to contribute to the development of cachexia, although this relationship is not clear. There is evidence that the etiology of these metabolic changes may be mediated by a neurohormonal response stimulated by the tumor. Because a single cause for these metabolic abnormalities has not been identified, several approaches to treatment of cancer cachexia have been reported. After correction of any underlying gastrointestinal abnormalities, single nutrients or other pharmacologic agents have been used in an attempt to favorably affect appetite or counter metabolic abnormalities that cause inefficient nutrient use. A variety of agents have been studied for their positive effects on appetite, including progestational agents, glucocorticoids, cannabinoids, cyproheptadine, olanzapine, and mirtazapine. Other agents have been investigated for their anti-inflammatory properties, including thalidomide, pentoxyphylline, melatonin, and omega-3 fatty acids. Anabolic agents such as testosterone derivatives have been investigated as well. The decision to treat symptoms of cancer cachexia should be based on the patient's desires and current medical condition. Choice of the most appropriate agent to treat unintentional weight loss in patients with cancer should include consideration of effects on appetite, weight, quality of life, and risk of adverse effects according to current evidence-based medicine, and cost and availability of the agent.

Skeletal muscle apoptosis is not increased in gastric cancer patients with mild–moderate weight loss

Numerous experimental and clinical studies have shown that skeletal muscle apoptotis may increase in wasting conditions and suggest that apoptosis might contribute to the loss of lean body mass. Data in cancer patients are still lacking. The present study aimed at verifying whether apoptosis was enhanced in the skeletal muscle of 16 patients with gastric cancer with respect to controls. A biopsy specimen was obtained from the rectus abdominis muscle. The occurrence of apoptosis in muscle biopsies was determined morphologically by the fluorescent transferase-mediated dUTP nick end labeling assay and by immunohistochemistry for caspase-3 and caspase-1. Mean weight loss was 6+/-2% in cancer patients and 0.5+/-0.1% in controls (p<0.0001). Serum albumin levels (g/dL) were 3.7+/-0.3 in cancer patients and 4.1+/-0.2 in controls (p<0.05). The percentage of apoptotic myonuclei was similar in cancer patients and in controls (1.5+/-0.3 versus 1.4+/-0.2, respectively; p=ns), in gastric cancer patients with mild (1.6+/-0.4) or moderate-severe weight loss (1.4+/-0.5) (p=ns), and in the different stages of disease (stages I-II: 1.5+/-0.7; stage III: 1.3+/-0.4; stage IV: 1.6+/-0.3; p=ns). By immunohistochemistry, caspase-1 and caspase-3 positive fibers were absent in controls and in neoplastic patients. Poly-ADP-ribosyl polymerase, a typical caspase-3 substrate whose processing is indicative of caspase-3 activation, was not cleaved in muscle biopsies of cancer patients. These data suggest that skeletal muscle apoptosis is not increased in neoplastic patients with mild-moderate weight loss and argue against the hypotheses that caspase-3 activation might be an essential step of myofibrillar proteolysis in cancer-related muscle wasting.

Prevention and treatment of cancer cachexia: new insights into an old problem

Cancer cachexia (CC) is a multifactorial paraneoplastic syndrome characterized by anorexia, body weight loss, loss of adipose tissue and skeletal muscle, accounting for at least 20% of deaths in neoplastic patients. CC significantly impairs quality of life and response to anti-neoplastic therapies, increasing morbidity and mortality of cancer patients. Muscle wasting is the most important phenotypic feature of CC and the principal cause of function impairment, fatigue and respiratory complications, mainly related to a hyperactivation of muscle proteolytic pathways. Most therapeutic strategies to CC have proven to be only partially effective . The inhibition of catabolic processes in muscle has been attempted pharmacologically with encouraging results in animal models. However, data in the clinical setting are still scanty and contradictory. Stimulation of muscle anabolism could represent a promising and valid therapeutic alternative for cancer-related muscle wasting. This goal may be currently achieved with the conventional, short-acting and adverse side effect-rich anabolic steroids. Insulin-like growth factor-1 (IGF-1) plays a critical role in muscle homeostasis, hypertrophy and regeneration. IGF-1 overexpression at the muscular level by gene therapy reverses muscle hypotrophy secondary to catabolic conditions and induces muscle hypertrophy increasing muscle mass and strength. This allows the speculation that this approach could also prove effective in modulating cancer-induced muscle wasting, while avoiding the potentially hazardous side effects of systemic IGF-1 administration. The present review will focus on the potential biochemical and molecular targets of CC therapy, and will define the rationale for a novel, gene therapy-based approach.

Malnutrition in Hemodialysis Patients: What Therapy?

Malnutrition is common in hemodialysis patients and is a powerful predictor of morbidity and mortality. Although much progress has been made in recent years in identifying the causes and pathogenesis of malnutrition in hemodialysis patients, as well as recognizing the link between malnutrition and morbidity and mortality, no consensus has been reached concerning its management. Along with such conventional interventions as nutritional counseling, oral nutritional supplements, and intradialytic parenteral nutrition, novel preventive and therapeutic strategies have been tested, such as appetite stimulants, growth hormone, androgenic anabolic steroids, and anti-inflammatory drugs, with contradictory and nonconclusive results. Malnutrition still remains a great challenge for nephrologists in the third millennium.

Branched-chain amino acids: the best compromise to achieve anabolism?

PURPOSE OF REVIEW

The anorexia-cachexia syndrome is highly prevalent in patients suffering from acute and chronic diseases, including cancer, chronic renal failure and liver cirrhosis. Once it has developed, it significantly influences the clinical course of the underlying disease, simultaneously impinging on patients' quality of life. Unfortunately, currently available therapeutic strategies do not appear to greatly impact on patients' morbidity, mortality and quality of life. More effective therapies are needed to promote appetite and food intake, to preserve lean body mass, and to ameliorate patients' psychological distress.

RECENT FINDINGS

Branched-chain amino acids are neutral amino acids with interesting and clinically relevant metabolic effects. Their potential role as antianorexia and anticachexia agents was proposed many years ago, but only recent experimental studies and clinical trials have tested their ability to stimulate food intake and counteract muscle wasting in anorectic, weight-losing patients. By interfering with brain serotonergic activity and by inhibiting the overexpression of critical muscular proteolytic pathways, branched-chain amino acids have been shown to induce beneficial metabolic and clinical effects under different pathological conditions.

SUMMARY

Based on the available data, branched-chain amino acids appear to exert significant antianorectic and anticachectic effects, and their supplementation may represent a viable intervention not only for patients suffering from chronic diseases, but also for those individuals at risk of sarcopenia due to age, immobility or prolonged bed rest, including trauma, orthopedic or neurologic patients.

Indomethacin preserves muscle mass and reduces levels of E3 ligases and TNF receptor type 1 in the gastrocnemius muscle of tumor-bearing mice

Tumor-induced skeletal muscle wasting involves tumor necrosis factor (TNF) and the ubiquitin-proteasome pathway of muscle protein degradation. In this study, growth of the colon-26 adenocarcinoma in mice was associated with diminished gastrocnemius muscle mass and increased muscle levels of actin, ubiquitin-conjugated proteins, free ubiquitin, E3 ubiquitin ligases, and the type 1 TNF receptor (TNFR1). Indomethacin at 1 or 5 mg/kg/day reduced tumor growth and muscle levels of TNFR1. However, only the 5 mg dose of indomethacin reduced muscle wasting and muscle levels of the E3 ligases and actin. These data suggest that the beneficial effects of indomethacin in the treatment of tumor-induced skeletal muscle wasting may involve inhibition of TNF- and ubiquitin-mediated pathways of muscle protein degradation. These data also demonstrate that E3 ligases, which are involved in disuse atrophy, also are associated with tumor-induced skeletal muscle wasting.

Therapy Insight: cancer anorexia–cachexia syndrome—when all you can eat is yourself

Tumor growth is associated with profound metabolic and neurochemical alterations, which can lead to the onset of anorexia-cachexia syndrome. Anorexia is defined as the loss of the desire to eat, while cachexia results from progressive wasting of skeletal muscle mass--and to a lesser extent adipose tissue--occurring even before weight loss becomes apparent. Cancer anorexia-cachexia syndrome is highly prevalent among cancer patients, has a large impact on morbidity and mortality, and impinges on patient quality of life. However, its clinical relevance is frequently overlooked, and treatments are usually only attempted during advanced stages of the disease. The pathogenic mechanisms of cachexia and anorexia are multifactorial, but cytokines and tumor-derived factors have a significant role, thereby representing a suitable therapeutic target. Energy expenditure in anorexia is frequently increased while energy intake is decreased, which further exacerbates the progressive deterioration of nutritional status. The optimal therapeutic approach to anorectic-cachectic cancer patients should be based on both changes in dietary habits, achieved via nutritional counseling; and drug therapy, aimed at interfering with cytokine expression or activity. Our improved understanding of the influence a tumor has on the host's metabolism is advancing new therapeutic approaches, which are likely to result in better preservation of nutritional status if started concurrently with specific antineoplastic treatment.