Nutritional support in multimodal therapy for cancer cachexia

Introduction Malnutrition has since long been known to be associated with adverse outcomes in cancer patients. The wasting in cancer cachexia involves loss of muscle and fat and reflects a catabolic metabolism induced by an abnormal host response to tumour presence and/or tumour factors. Patients with cancer cachexia frequently develop a chronic negative energy and protein balance driven by a combination of reduced food intake and metabolic change. Thus, alterations in both energy intake and components of energy expenditure may contribute to progressive weight loss. Increased resting energy expenditure related to the systemic inflammatory response is common and a sustained hypermetabolism over a long period of disease progression can make a large contribution to negative energy balance and wasting if not compensated for by an increase in energy intake. Hypermetabolism and diminished energy intake due to anorexia may thus constitute a vicious circle in the development of cancer cachexia. Discussion Though nutritional support alone can improve energy intake to a variable extent and for a variable period of time, it will not address the underlying catabolic metabolism and is thus likely to be of limited efficacy if attempts to attenuate the tumour-induced catabolic response are not carried out at the same time. Concomitant drug treatments for cancer cachexia may slow down the wasting process by reducing anorexia, attenuating the systemic inflammation, the skeletal muscle catabolism or stimulating the muscle protein anabolism. Thus, improved management of cancer cachexia may require a multimodal approach by a multi-disciplinary team and is best commenced earlier rather than later. Early start of therapy also facilitates the use of oral nutritional supplementation, which is preferable to parenteral nutrition in the majority of cases. Once a patient is severely wasted it may be neither practical nor ethical to intervene with anything else than supportive care. Conclusion An improvement in the condition of all patients with cachexia may not be possible, however, the goal must be to stabilise cachexia and prevent or delay further decline. There is currently no single or combined treatment strategy which is successful in all patients. However, strategies to counteract both hypermetabolism and reduced dietary intake have been demonstrated to be of importance for the survival, function and quality of life of cancer patients and should be further explored in interventional studies. Presented as invited lecture at the MASCC/ISOO 20th Anniversary International Symposium Supportive Care in Cancer in St. Gallen, June 2007.     

Obesity and the metabolic response to severe multiple trauma in man.

In the obese state profound metabolic disturbances exist and it is not known how this disrupted metabolism in obese subjects (body mass index greater than 30) may change their ability to respond to the superimposed, injury-induced stress. Understanding the mechanisms that modify the metabolic parameters in traumatized obese patients is essential in their nutritional assessment and further treatment. We have investigated in 7 obese and 10 nonobese multiple trauma patients, on a whole-body level, the energy metabolism, protein kinetics, and lipolysis in the early catabolic "flow phase" of severe injury when they were receiving maintenance fluids without calories or nitrogen. Traumatized obese patients mobilized relatively more protein and less fat compared with nonobese subjects. A relative block both in lipolysis and fat oxidation is experienced by injured obese patients that results in a shift to preferential use of proteins and carbohydrates. Reduced endogenous protein synthetic efficiency observed in obese patients implies increased protein recycling. Thus obese patients could not effectively use their most abundant fat fuel sources and have to depend on other fuel sources. The nutritional management of obese trauma victims should therefore be tailored towards provision of enough glucose calories to spare protein.     

"AMPing up" our understanding of the hypothalamic control of energy balance

AMP-activated protein kinase (AMPK) has emerged as a metabolic "fuel gauge," which oscillates between anabolic and catabolic processes that ultimately influence energy balance. A study in this issue of the JCI by Claret et al. now extends the role of AMPK in medial basal hypothalamic neurons (see the related article beginning on page 2325). These findings maintain AMPK signaling as a common cellular mechanism in proopiomelanocortin and neuropeptide Y/agouti-related protein neurons and links hypothalamic AMPK to coordinated energy and glucose homeostasis.     

Leucine suppresses acid-induced protein wasting in L6 rat muscle cells

BACKGROUND: Metabolic acidosis induces protein wasting in skeletal muscle cells, accompanied by decreased glycolysis and compensatory increased consumption of other metabolic fuels, implying that protein wasting arises from fuel starvation and might be rectified by fuel supplements. Design To test this hypothesis, total protein and protein degradation (release of 14C-phenylalanine) were measured in L6 skeletal muscle cells cultured in Eagle's Minimum Essential Medium at pH 7.1-7.5 for 3 days with metabolic inhibitors or metabolic fuel supplements. RESULTS: Inducing metabolic fuel starvation with inhibitors (1 mmol L(-1) 2-deoxyglucose or 0.1 mmol L(-1) KCN [potassium cyanide]) failed to stimulate protein degradation or net protein wasting under nonacidaemic conditions (pH 7.5). Conversely metabolic fuel supplements (1 mmol L(-1) octanoate, pyruvate or alanine) failed to increase the protein content of the cultures at any pH tested, in spite of significant consumption of the fuels by the cells. Only leucine (1-3 mmol L(-1)) increased protein content and suppressed protein degradation in opposition to the catabolic effect of acidaemia (pH 7.1). Conclusion Leucine exerts a beneficial anabolic effect on cultured skeletal muscle cells in the face of metabolic acidaemia. The failure of other metabolic fuels to do this, and of the metabolic inhibitors to exert a catabolic effect, suggests that leucine acts as a specific modulator of protein turnover and not as a nonspecific source of carbon for oxidation as a fuel.     

Protein sparing and protein replacement in acutely injured patients during TPN with and without amino acid supply

The metabolic effects of TPN were studied in a selected group of trauma patients. Nineteen patients were randomly divided into two groups: the first was treated with glucose and insulin, the second with glucose, insulin and amino acids. Each patient in both groups received TPN isocaloric with respect to daily energy output and the treatment lasted five days. Each group was further divided into two subsets (severe or moderate catabolism) according to fasting energy output with respect to the expected energy expenditure. During the acute flow phase, both in moderate as well as in severe catabolism, glucose and insulin were effective for protein sparing; the maximum protein sparing effect was reached when giving a caloric intake equal to 130% of daily energy output. Glucose, insulin and amino acids were effective in replacement of nitrogen losses. In moderately catabolic patients nitrogen balance was significantly better than in severely catabolic patients. This study shows that early and short-term TPN is effective in controlling the flow phase of trauma. Glucose and insulin appear to be the determinants of the protein sparing effect when given in amounts equal to those needed; amino acids provided protein replacement when given in amounts equal to about 20% of energy output. Energy supply higher than 120–130% of daily energy output does not increase protein sparing and protein replacement, the only effect being a further increase in metabolism, which is possibly dangerous in critically ill patients.     

Tissue inhibitor of metalloproteinase-1 levels in plasma from tumour arteries and veins of patients with rectal cancer

OBJECTIVE: Tissue inhibitor of metalloproteinase-1 (TIMP-1) plays a major role in the regulation of tissue growth, including cancer growth. The TIMP-1 protein can be determined in plasma, and increased plasma levels of TIMP-1 are associated with a poor prognosis of colorectal cancer patients. The aim of the present study was to evaluate whether tumour tissue release of the TIMP-1 protein contributes to the increased plasma levels of TIMP-1 observed in patients with colorectal cancer. MATERIAL AND METHODS: Preoperative blood samples from a peripheral vein and intraoperative blood samples from a tumour artery, a tumour vein and from a peripheral vein were drawn from 24 patients undergoing elective, intended curative surgery for primary rectal cancer. TIMP-1 levels were determined concurrently in plasma from all samples using a validated ELISA method. Counts of white blood cells and platelets were also carried out. RESULTS: No significant differences between plasma TIMP-1 levels could be demonstrated in any compartment. In particular, there was no significant difference in TIMP-1 levels in plasma from tumour arteries and tumour veins. However, there was a significant decrease in neutrophil cell counts from tumour arteries to tumour veins (p<0.001). CONCLUSIONS: The present results do not support the current hypothesis that tumour cells contribute substantially to increased plasma TIMP-1 levels observed in patients with colorectal cancer.     

Recombinant immunotoxins for cancer therapy

Recombinant immunotoxins consist of Fv regions of tumour-selective antibodies fused to toxins found in bacteria, plants or fungi. These toxins must be modified to remove normal-tissue binding sites but to retain all other functions of cytotoxicity. The recombinant antibody fragments target the modified toxin to cancer cells which are killed, either by direct inhibition of protein synthesis, or by concomitant induction of apoptosis. Cells that are not recognised by the antibody fragment because they do not carry the tumour antigen, are spared. Many factors influence the in vivo antitumour activity of recombinant immunotoxins. Among them are considerations of which types of cancer may be the best targets for immunotoxin therapy as well as tumour specificity of the antigen that is targeted by the recombinant antibody. Other relevant issues are the affinity of immunotoxins and their ability to enter and penetrate into tissues and tumours, which in turn is dependent on the size of the protein. A great deal of protein-engineering is required to stabilise the recombinant antibody moiety of immunotoxins, since stability of the molecules is crucial for good clinical efficacy. Excellent activity and specificity can be observed for many recombinant immunotoxins in in vitro assays using cultured cancer cells as well as in animal tumour models. Ongoing clinical trials provide examples where the promising preclinical data correlate with successful results in experimental cancer therapy.     

Nitrogen metabolism and renal amino acid excretion during total parenteral feeding of hypermetabolic patients with various carbohydrate regimes

During an investigative study about the utilization of parenterally administered amino-acids (AA) in severe catabolic states nitrogen balances, urea production rates and catabolic nitrogen as well as urinary losses of amino-acids were determined in six adult polytraumatized patients treated in an intensive care unit. In addition to 19 g nitrogen (0.3 g N/kg/day) 3,000 kcal (12.5 MJ) were given simultaneously as carbohydrates. Either a mixture of laevulose 20%, glucose 10%, xylitol 10% (LGX) or glucose 50% were infused alternatively for four days in a randomized cross-over scheme. Another group of three patients received the LGX-regime alone for six days altogether. Higher urinary N-losses, increased urea production rates corresponding to a rise in the s.c. catabolic nitrogen were obtained on days where the LGX-mixture was infused; there was also an increased excretion of alpha-amino-N due to a distinct aminoaciduria. Not all amino-acids did react in the same manner. When comparing excretion to supply higher losses (greater than 20%) were observed for: THR greater than TRY greater than VAL greater than ILE greater than PHE. Methionine and alanine were also excreted in higher amounts, whereas under glucose an elevated excretion was especially noted with glutamine and alpha-aminobutyric acid. The increased urea production rate associated with a reduced incorporation of amino-acids as well as the accentuated renal AA-losses under LGX may be ascribed to a slight increase in protein catabolism connected with some impairment of AA-utilization due to a temporary metabolic hepatic 'block'. Under glucose an intensified endogenous mobilization as well as the higher exogenous supply of insulin might be responsible for a somewhat better AA-utilization. Amino-acid clearances under the carbohydrate mixture in the second group were - with the exception of lysine and leucine - raised distinctly similar to values seen in aminoaciduria of other origin. This leads to the assumption that the AA-overflow might result from a partial insufficiency or overload of renal transport ('carrier') systems being responsible for amino-acid reabsorption. The question of an adequate supply - concerning essential amino acids in particular - taking into consideration the relatively high losses under one of the nutritional regimes investigated is shortly touched upon. Finally the possibility of adapting AA-mixtures to the respective carbohydrate solutions in order to improve nitrogen balances and utilization is discussed.     

Changes in taste sensation and feeding behaviour in cancer patients: a review.

Recent studies suggest the importance of alterations in taste sensation as a determinant of anorexia in cancer patients. These studies collectively support the conclusions that the likelihood of developing abnormalities in taste increases with increasing body burden of tumour, that taste abnormality is reversible on response of the underlying tumour to therapy, and that the abnormalities in taste can be correlated with decreased intake of energy. It is suggested that these studies, and studies currently in progress, may aid our understanding of food choices in cancer patients and may guide the use of food supplements to assist the cancer patient in maintaining adequate energy intake.     

Biochemical methods for the determination of a clinical protein catabolism

1. 20 patients before surgery received enteral nutrition for three days (12 g nitrogen, 1800 Kcal). Nitrogen and urea excretions in urine during the second and third day were determined. Eleven patients had a negative nitrogen balance (-2,7 and -2,4 g/day). In these patients urea production rates were 21,1 and 20,1 g/day. An urea production rate exceeding 15 g urea/day is probable an indication for a protein catabolism. The reason for this catabolic state seems to be a decreased protein utilisation (49 and 47 percent) as the result of a metabolic stress situation. This metabolic stress was determined according the stress index (Bistrian). The patients were in a stress situation comparable to postoperative stress (+3,7 and +3,9). The determination of urea production rate and catabolic index seems a suitable tool for defining a catabolic state. 2. 3-met-histidine excretion in urine were measured in seven patients postoperatively. In different periods saline or aminoacids solutions (5% alanine) were infused. During alanine administration protein (+49%)--and 3-met-histidine excretions (+50%) increased. It is not possible to state a catabolic situation out of the 3-met-histidine excretion, because an increased excretion may result from a stimulated protein synthesis in muscle tissue or from an increased muscleprotein wasting. 3. Free amino acid pools in plasma and muscle tissue were analysed in patients with severe illness of liver and pancreas. The free amino acid pattern differed from healthy volunteers. In patients with liver disease significantly increased concentrations of phenylalanine, tyrosine and methionine were found. In patients with acute pancreatitis highly abnormal pattern of intracellular amino acids occurred with decreased concentrations of glutamine, cysteine, histidine, lysine, arginine and ornithine. The highly significant decreased concentrations of glutamine (p less than 0,01) indicate a catabolic situation of these patients. A quantification of the severity of the catabolic state out of amino acid concentrations is not possible.     

Metabolic response to feeding in weight-losing pancreatic cancer patients and its modulation by a fish-oil-enriched nutritional supplement

Weight-losing patients with advanced cancer often fail to gain weight with conventional nutritional support. This suboptimal response might be explained, in part, by an increased metabolic response to feeding. It has been suggested that eicosapentaenoic acid (EPA) can modify beneficially the metabolic response to cancer. The aim of the present study was to examine the metabolic response to feeding in cancer and the effects of an EPA-enriched oral food supplement on this response. A total of 16 weight-losing, non-diabetic patients with unresectable pancreatic adenocarcinoma and six healthy, weight-stable controls were studied by indirect calorimetry in the fasting and fed states. Body composition was estimated by bioimpedence analysis. Cancer patients were then given a fish-oil-enriched nutritional supplement providing 2 g of EPA and 2550 kJ daily, and underwent repeat metabolic study after 3 weeks of such supplementation. At baseline, resting energy expenditure whether expressed per kg body weight, lean body mass or body cell mass was significantly greater in the cancer patients compared with controls. Fat oxidation was significantly higher in the fasting state in cancer patients [median 1.26 g.kg(-1).min(-1) (interquartile range 0.95-1.38)] than in controls [0.76 g.kg(-1). min(-1) (0.62-0.92); P<0.05]. Over the 4 h feeding period, changes in insulin and glucose concentrations in cancer patients suggested relative glucose intolerance. In response to oral meal feeding, the percentage change in the area under the curve of energy expenditure was significantly lower in the cancer patients [median 7.9% (interquartile range 3.4-9.0)] than in controls [12.6% (9.9-15.1); P<0.01]. After 3 weeks of the EPA-enriched supplement, the body weight of the cancer patients had increased and the energy expenditure in response to feeding had risen significantly [9.6% (6. 3-12.4)], such that it was no different from baseline healthy control values. Similarly, fasting fat oxidation fell to 1.02 g. kg(-1).min(-1) (0.8-1.18), again no longer significantly different from baseline healthy control values. While weight-losing patients with advanced pancreatic cancer have an increased resting energy expenditure and increased fat oxidation, the energy cost of feeding is, in fact, reduced. Provision of a fish-oil-enriched nutritional supplement results in some normalization of the metabolic response in both the fasted and fed states, in association with an improvement in nutritional status.     

Nutrition in the intensive care patient

The experiences of the past decades have shown that critically ill patients regularly suffer marked tissue depletion. Recently, it has come to light that malnutrition may cause this depletion. The need, thus, arises for a comprehensive study of nutrition in the intensive care unit, a study relating present knowledge concerning the metabolic and catabolic states of the critically ill to possible applications in parenteral nutritional support.     

Tissue inhibitor of metalloproteinase‐1 levels in plasma from tumour arteries and veins of patients with rectal cancer

Objective. Tissue inhibitor of metalloproteinase‐1 (TIMP‐1) plays a major role in the regulation of tissue growth, including cancer growth. The TIMP‐1 protein can be determined in plasma, and increased plasma levels of TIMP‐1 are associated with a poor prognosis of colorectal cancer patients. The aim of the present study was to evaluate whether tumour tissue release of the TIMP‐1 protein contributes to the increased plasma levels of TIMP‐1 observed in patients with colorectal cancer. Material and methods. Preoperative blood samples from a peripheral vein and intraoperative blood samples from a tumour artery, a tumour vein and from a peripheral vein were drawn from 24 patients undergoing elective, intended curative surgery for primary rectal cancer. TIMP‐1 levels were determined concurrently in plasma from all samples using a validated ELISA method. Counts of white blood cells and platelets were also carried out. Results. No significant differences between plasma TIMP‐1 levels could be demonstrated in any compartment. In particular, there was no significant difference in TIMP‐1 levels in plasma from tumour arteries and tumour veins. However, there was a significant decrease in neutrophil cell counts from tumour arteries to tumour veins (p<0.001). Conclusions. The present results do not support the current hypothesis that tumour cells contribute substantially to increased plasma TIMP‐1 levels observed in patients with colorectal cancer.     

Cachectin/tumor necrosis factor induces cachexia, anemia, and inflammation

Cachexia is a potentially lethal syndrome of unknown etiology characterized by anorexia, weight loss, and protein wasting that frequently complicates the treatment of chronic inflammation and cancer. Cachectin/TNF was isolated during the search for a humoral mediator of cachexia and found to stimulate the breakdown of energy stores from adipocytes and myocytes in vitro, but the chronic effects of the monokine in vivo are not known. Sublethal doses of recombinant human cachectin administered twice daily for 7-10 d caused cachexia in rats, as evidenced by reduced food intake, weight loss, and depletion of whole-body lipid and protein stores. Significant anemia is also observed and found to be the result of decreased red blood cell mass, not expanded plasma volume. Leukocytosis and histopathological evidence of tissue injury and inflammation are observed in several organs, including omentum, liver, spleen, and heart. These data suggests that the exposure of the normal host to cachectin is capable of inducing a pathophysiological syndrome of cachexia, anemia, and inflammation similar to that observed during inflammatory states or malignancy.     

Growth hormone therapy for protein catabolism

GH and IGF-I have shown remarkable consistency of effect in a wide range of catabolic conditions. Doses of around 10 IU/m2/day of GH and 80 micrograms/kg/day of IGF-I over short periods of time can improve net protein synthesis and preserve lean body mass. Most studies have reported metabolic endpoints, but favorable clinical effects have included decreased hospital stay and mortality in burns, improved respiratory muscle function in COAD, preserved grip strength post- operatively, and improvements in cardiac and bowel failure. Adverse effects of GH treatment are uncommon and usually related to glycaemic control. GH and IGF-I have differential effects on insulin concentrations--increasing or decreasing concentrations, respectively. The hypoglycaemic effects of IGF-I are dependent on route of administration and are avoided by subcutaneous delivery. Occasional patients have needed to discontinue GH treatment due to hyperglycaemia, although the anabolic action of GH may be partially mediated by increased insulin levels. The co-administration of GH and IGF-I has theoretical advantages by both increasing IGF binding-protein concentrations and balancing glycaemic control. An initial study with combination therapy in calorically-restricted volunteers has shown anabolic effects greater than with either agent alone. This approach requires further study in catabolic patients. There is a need for large, well-designed trials with clinical rather than purely metabolic end-points, and some of these are already underway. Should these studies confirm the early findings, financial considerations will become paramount, although it remains possible that treatment may be self-financing if lengths of hospital admissions are shortened.      

C reactive protein in pancreatic cancer and chronic pancreatitis

Serum C reactive protein was determined in 30 control subjects, 32 patients with pancreatic cancer, 28 with chronic pancreatitis and 23 with extra-pancreatic diseases of the upper gastrointestinal tract. The aim was to ascertain possible alterations of this index in chronic pancreatic disease and to speculate on some influencing factors. Higher C reactive protein levels were found in pancreatic cancer as compared to controls. Pancreatic cancer patients with systemic metastases had higher levels of this index compared to those with non-metastatic disease. Raised concentrations of C reactive protein were detected in 7/28 subjects with chronic pancreatitis. In this group these higher levels were found in patients in a relapsing phase of the disease; no association was observed with pancreatic pseudocysts. Among all subjects a correlation was found, between C reactive protein and age; patients with abnormal fasting blood glucose levels or increased white blood cell count had higher levels of this protein as compared to the remaining patients. We may conclude that C reactive protein increases in pancreatic cancer, specially in relation to tumour extent; in chronic pancreatitis it reflects the inflammatory status of the gland. While acting in the context of the acute phase response, this test may provide an adjunct in evaluating patients with a chronic pancreatic disease.     

The role of cytokines in cancer cachexia

A large number of observations point towards cytokines, polypeptides released mainly by immune cells, as the molecules responsible for the metabolic derangements associated with cancer-bearing states. Indeed, these alterations lead to a pathological state known as cancer cachexia which is, unfortunately, one of the worst effects of malignancy, accounting for nearly a third of cancer deaths. It is characterized by weight loss together with anorexia, weakness, anemia, and asthenia. The complications associated with the appearance of the cachectic syndrome affect both the physiological and biochemical balance of the patient and have effects on the efficiency of the anticancer treatment, resulting in a considerably decreased survival time. At the metabolic level, cachexia is associated with loss of skeletal muscle protein together with a depletion of body lipid stores. The cachectic patient, in addition to having practically no adipose tissue, is basically subject to an important muscle wastage manifested as an excessive nitrogen loss. The metabolic changes are partially mediated by alterations in circulating hormone concentrations (insulin, glucagon, and glucocorticoids in particular) or in their effectiveness. The present study reviews the involvement of different cytokines in the metabolic and physiological alterations associated with tumor burden and cachexia. Among these cytokines, some can be considered as procachectic (such as tumor necrosis factor-alpha), while others having opposite effects can be named as anticachectic cytokines. It is the balance between these two cytokine types that finally seems to have a key role in cancer cachexia.