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Relationship between tumor growth and cachexia during progressive malignant disease: a new measure of the extent of cachexia, the cachexia index.

The relationship between the dynamics of tumor growth and the development of cachexia in C57b1/6j mice bearing the syngeneic transplantable adenocarcinoma EO 771 has been studied. The tumors grow independently of the inoculum size according to the Gompertzian mode of growth, with a maximum growth rate at a tumor size of about 3 g. As a dynamic measure of the degree of cachexia, the cachexia index "K", i.e. the quotient of the alteration of the carcass weight of the animal divided by the alteration of the tumor weight during the same time interval, is introduced. K is superior to a simple estimation of the alteration of the carcass animal weight because it also considers local weight-reducing effects of the infiltrating tumor growth. With respect to cachexia, three phases of tumor growth can be distinguished; cachexia develops mainly during the 2nd phase, i.e. for tumor sizes between 1.0 to 3.5 g which strongly correlates with the maximum growth rate of the tumor.

Adenocarcinoma↗

Effect of a fluorinated pyrimidine on cachexia and tumour growth in murine cachexia models: relationship with a proteolysis inducing factor.

The fluorinated pyrimidine nucleoside, 5'-deoxy-5-fluorouridine (5'-dFUrd) has been shown to effectively attenuate the progress of cachexia in the murine adenocarcinomas MAC16 and colon 26 as well as in the human uterine cervical carcinoma xenograft, Yumoto. Although concomitant inhibition of tumour growth was observed in all three models this was not sufficient to account for the preservation of body weight. An attempt has been made to correlate the anti-cachectic activity of 5'-dFUrd with the presence of a tumour produced proteolysis-inducing factor (PIF), thought to be responsible for the development of cachexia in the MAC16 model. Two variants of colon 26 adenocarcinoma were employed, clone 20 which produces profound cachexia, and clone 5 which produces no change in body weight in recipient animals. Mice bearing the colon 26, clone 20 variant showed evidence for the presence of PIF in tumour, serum and urine, while there was no evidence for the presence of PIF in tumour or body fluids of mice bearing the clone 5 tumours. Treatment of animals bearing the clone 20 variant with 5'-dF Urd led to the disappearance of PIF from the tumour, serum and urine concomitant with the attenuation of the development of cachexia. The human cervical carcinoma, Yumoto, which also induced cachexia in recipiant animals, showed expression of PIF in tumour, serum and urine in control and vehicle-treated mice, but was absent in mice treated with 5'-dFUrd. Thus in these experimental models cachexia appears to be correlated with the presence of PIF.

Adenocarcinoma↗

Experimental cancer cachexia: the role of host-derived cytokines interleukin (IL)-6, IL-12, interferon-gamma, and tumor necrosis factor alpha evaluated in gene knockout, tumor-bearing mice on C57 Bl background and eicosanoid-dependent cachexia.

MCG 101 tumors were implanted sc. on wild-type C57 Bl and gene knockout mice to evaluate the role of host-produced cytokines [interleukin (IL)-6, IL-12, IFNgamma, tumor necrosis factor (TNF) receptor 1, and TNF receptor 2] to explain local tumor growth, anorexia, and carcass weight loss in a well-defined model with experimental cachexia. Indomethacin was provided in the drinking water to explore interactions between host and tumor-derived prostaglandins and proinflammatory cytokines for tumor growth. Wild-type tumor-bearing mice developed cachexia because of rapid tumor growth, which were both attenuated in IL-6 gene knockouts. Similar findings were observed after provision of anti-IL-6 to wild-type tumor-bearing mice. Alterations in food intake were not directly related to systemic IL-6 but rather secondarily to IL-6-dependent tumor growth. The absence of host-derived IL-12, IFN-gamma, or the TNF receptor 1 or receptor 2 gene did not attenuate tumor growth or improve subsequent cachexia. Thus, carcass weight loss was not improved by the omission of host cytokine (TNF-alpha, IL-12, or IFN-gamma) except for IL-6. Systemic indomethacin provision decreased plasma prostaglandin E2 in five of six groups of gene knockout tumor-bearing mice, which was associated with improved carcass weight in these groups. Indomethacin seemed to improve food intake to a similar extent in both wild-type and gene knockouts, which agree with the speculation that eicosanoids are more important to explain anorexia than host cytokines. Our results demonstrate that host- and tumor-derived cytokines and prostaglandins interact with tumor growth and promote cachexia in a more complex fashion than usually presented based on previous information in studies on either anti-cytokine experiments in vivo or on gene knockouts with respect to a "single cytokine model." Overall, host cytokines were quantitatively less important than tumor-derived cytokines to explain net tumor growth, which indirectly explains subsequent cachexia and anorexia.

Animals↗

Expression of the human cachexia-associated protein (HCAP) in prostate cancer and in a prostate cancer animal model of cachexia.

Prostate cancer (CaP) patients with disseminated disease often suffer from severe cachexia, which contributes to mortality in advanced cancer. Human cachexia-associated protein (HCAP) was recently identified from a breast cancer library based on the available 20-amino acid sequence of proteolysis-inducing factor (PIF), which is a highly active cachectic factor isolated from mouse colon adenocarcinoma MAC16. Herein, we investigated the expression of HCAP in CaP and its potential involvement in CaP-associated cachexia. HCAP mRNA was detected in CaP cell lines, in primary CaP tissues and in its osseous metastases. In situ hybridization showed HCAP mRNA to be localized only in the epithelial cells in CaP tissues, in the metastatic foci in bone, liver and lymph node, but not in the stromal cells or in normal prostate tissues. HCAP protein was detected in 9 of 14 CaP metastases but not in normal prostate tissues from cadaveric donors or patients with organ-confined tumors. Our Western blot analysis revealed that HCAP was present in 9 of 19 urine specimens from cachectic CaP patients but not in 19 urine samples of noncachectic patients. HCAP mRNA and protein were also detected in LuCaP 35 and PC-3M xenografts from our cachectic animal models. Our results demonstrated that human CaP cells express HCAP and the expression of HCAP is associated with the progression of CaP and the development of CaP cachexia.

Animals↗

Mechanisms of experimental cancer cachexia. Interaction between mononuclear phagocytes and colon-26 carcinoma and its relevance to IL-6-mediated cancer cachexia.

In a recent report we showed that IL-6 is an important mediator of experimental cancer cachexia in the colon-26 (C-26) tumor system. In culture, on a per cell basis, C-26.IVX cell line (which develops tumors and induces severe cachexia of syngeneic hosts) produces up to 60-fold less IL-6 than single cell suspensions prepared from freshly excised tumors. In this study, the mechanism behind this observation was investigated. Analysis of the cellular composition of progressing C-26 tumors indicated they contained up to 6% of macrophages. T cells, B cells, and granulocytes were not detected in the tumors. Because C-26.IVX line grown in vitro contained no macrophages, the possibility that macrophage products may augment IL-6 synthesis by the tumor cells was tested. Indeed, IL-1 beta in a dose-dependent manner and at picogram amounts could potentiate IL-6 production by the C-26 cell line. The presence of high affinity receptors for IL-1 on the C-26.IVX cell line was established. These cells expressed approximately 1500 IL-1 sites per cell with a dissociation constant of approximately 20 pM. Next, we attempted to mimic the situation in vivo by coculture of C-26.IVX cells with syngeneic peritoneal macrophages and found that this condition gives rise to an augmented IL-6 production similar to that observed with in vivo derived tumor cells or rIL-1 beta-treated C-26.IVX cells. Furthermore, anti-IL-1 type I receptor antibody completely blocked C-26.IVX IL-6 production induced by either rIL-1 beta or by peritoneal macrophages. Taken together, these data suggest a pathway of IL-6 production by C-26 tumors that involves a cellular interaction between IL-1R-expressing tumor cells and host-derived macrophages. The results also suggest that this interaction significantly contributes to cachectic events endured by the tumor-bearing host.

Animals↗

Cachexia-like symptoms predict a worse prognosis in localized t1 renal cell carcinoma.

PURPOSE: Although cachexia is a common sequela of advanced and metastatic renal cell carcinoma (RCC), cachexia-like symptoms may also represent a paraneoplastic finding. We assessed the prognostic significance of these symptoms in patients with stage T1 RCC. MATERIALS AND METHODS: Using the kidney cancer database at our institution 250 patients were identified who underwent partial or radical nephrectomy for T1N0M0 RCC between 1989 and 2001. The prognostic significance of the symptoms present at diagnosis and findings on preoperative laboratory evaluation were examined. RESULTS: Mean and median followup was 33 and 43 months, respectively. Malaise, weight loss, anorexia and hypoalbuminemia were cachexia related findings that were significant predictors of worse disease specific survival (DSS). DSS in patients with 1 vs greater than 1 cachexia related symptoms was not significantly different (p = 0.077). Therefore, any patient with at least 1 cachexia related finding was considered to be positive for cachexia and cachexia occurred in 37 (14.8%). Cachexia was associated with significantly worse recurrence-free survival (HR 3.03, p = 0.032) and DSS (HR 4.39, p = 0.011) even after controlling for tumor size, grade and performance status. The 5-year survival rate in patients with low grade (1 or 2) tumors with and without cachexia was 91% and 81%, respectively. The 5-year survival rate in patients with high grade (3 or 4) tumors with and without cachexia was 75% and 55%, respectively. CONCLUSIONS: Cachexia-like symptoms independently predict a worse prognosis in patients with T1 RCC. Patients with cachexia (malaise, weight loss, anorexia and hypoalbuminemia), especially when associated with high grade tumors, should be considered for clinical trials of adjuvant therapies.

Aged↗

Tumor necrosis factor and cachexia: a current perspective.

Anorexia, net proteolysis of skeletal muscle and consumption of body fat are hallmarks of the cachexia syndrome associated with chronic disease states. While inanition contributes to cachexia, this wasting diathesis has little in common with simple starvation. The cachexia syndrome is characterized by progressive weight loss and depletion of lean body mass in excess to that resulting from comparable caloric restriction. Accelerated mobilization and consumption of host protein stores from peripheral tissues occurs to support gluconeogenesis and acute phase protein synthesis [1, 2]. In contrast, simple starvation is associated with a relative sparing of lean tissue with the preferential consumption of fat. While the clinical manifestations of cachexia are readily apparent, identification of the specific mechanisms responsible for the development of cachexia remains an enigma. In recent years, interest has focused on the role that the immune system plays in the development of cachexia. Investigators initially hypothesized that the chronic production of two inflammatory cytokines, tumour necrosis factor alpha (TNF alpha) and/or interleukin-1 (IL-1), could explain the host non-specific responses resulting in cachexia [3-5]. Other pro-inflammatory cytokines, including interleukin-6 (IL-6) [6, 7] and interferon-gamma [8, 9], have been more recently proposed to be involved in this complex process. Although no consensus exists for the exclusive role of any one cytokine in the pathogenesis of cachexia, there is growing acceptance that the progression of cachexia results in part from the inappropriate release of one or more pro-inflammatory cytokines [10, 11]. In the present review, the current role of TNF alpha as a mediator of cachexia is examined.

Cachexia↗

Cachexia in rheumatoid arthritis.

Rheumatoid arthritis is a debilitating, chronic, systemic, autoimmune disease of unknown etiology that causes destruction of joint cartilage and bone. It generally occurs between the fourth and sixth decades of life, and affects two to three times more women than men. It is characterized by joint stiffness, pain, and swelling, and is accompanied by a loss of body cell mass. This loss of cell mass, known as rheumatoid cachexia, predominates in skeletal muscle, but also occurs in the viscera and immune system. Thus, rheumatoid cachexia leads to muscle weakness and a loss of functional capacity, and is believed to accelerate morbidity and mortality in rheumatoid arthritis. Currently there is no established mechanism for rheumatoid cachexia, but it is accompanied by elevated resting energy expenditure, accelerated whole-body protein catabolism, and excess production of the inflammatory cytokines, tumor necrosis factor-alpha and interleukin-1beta. Tumor necrosis factor-alpha is probably the central mediator of muscle wasting in rheumatoid arthritis, and is known to act synergistically with interleukin-1beta to promote cachexia. In general, tumor necrosis factor-alpha and interleukin-1beta are thought to alter the balance between protein degradation and protein synthesis in rheumatoid arthritis to cause muscle wasting. The precise mechanism by which they do this is not known. Reduced peripheral insulin action and low habitual physical activity are important consequences of rheumatoid arthritis, and have also been implicated as mediators of rheumatoid cachexia. Insulin inhibits muscle protein degradation. Consequently, reduced peripheral insulin action in rheumatoid arthritis is thought to be permissive to cytokine-driven muscle loss. The cause of reduced peripheral insulin action in rheumatoid arthritis is not known, but tumor necrosis factor-alpha has been shown to interfere with insulin receptor signaling and is probably an important contributor. Low habitual physical activity has consistently been observed in rheumatoid arthritis and is an important consequence of, and contributor to, muscle wasting. In addition, low physical activity predisposes to fat gain and is believed to precipitate a negative reinforcing cycle of muscle loss, reduced physical function, and fat gain in rheumatoid arthritis, which leads to 'cachectic obesity'. To date, there is no standard treatment for rheumatoid cachexia. However, physical exercise is currently believed to be the most important and clinically relevant countermeasure against rheumatoid cachexia. In general, a combination of skeletal muscle strength training and aerobic exercise is recommended, but must be prescribed with the patient's disease status, overall health, and safety in mind. Future studies should investigate the safety, efficacy, and required dose of anti-cytokine therapy for the treatment of rheumatoid cachexia. In this review, we outline the current definition of rheumatoid cachexia, and discuss the etiology, pathogenesis, and treatment of rheumatoid cachexia.

Arthritis, Rheumatoid↗

Central nervous system mechanisms contributing to the cachexia-anorexia syndrome.

The cachexia-anorexia syndrome occurs in chronic pathophysiologic processes including cancer, infection with human immunodeficiency virus, bacterial and parasitic diseases, inflammatory bowel disease, liver disease, obstructive pulmonary disease, cardiovascular disease, and rheumatoid arthritis. Cachexia makes an organism susceptible to secondary pathologies and can result in death. Cachexia-anorexia may result from pain, depression or anxiety, hypogeusia and hyposmia, taste and food aversions, chronic nausea, vomiting, early satiety, malfunction of the gastrointestinal system (delayed digestion, malabsorption, gastric stasis and associated delayed emptying, and/or atrophic changes of the mucosa), metabolic shifts, cytokine action, production of substances by tumor cells, and/or iatrogenic causes such as chemotherapy and radiotherapy. The cachexia-anorexia syndrome also involves metabolic and immune changes (mediated by either the pathophysiologic process, i.e., tumor, or host-derived chemical factors, e.g., peptides, neurotransmitters, cytokines, and lipid-mobilizing factors) and is associated with hypertriacylglycerolemia, lipolysis, and acceleration of protein turnover. These changes result in the loss of fat mass and body protein. Increased resting energy expenditure in weight-losing cachectic patients can occur despite the reduced dietary intake, indicating a systemic dysregulation of host metabolism. During cachexia, the organism is maintained in a constant negative energy balance. This can rarely be explained by the actual energy and substrate demands by tumors in patients with cancer. Overall, the cachectic profile is significantly different than that observed during starvation. Cachexia may result not only from anorexia and a decreased caloric intake but also from malabsorption and losses from the body (ulcers, hemorrhage, effusions). In any case, the major deficit of a cachectic organism is a negative energy balance. Cytokines are proposed to participate in the development and/or progression of cachexia-anorexia; interleukin-1, interleukin-6 (and its subfamily members such as ciliary neurotrophic factor and leukemia inhibitory factor), interferon-gamma, tumor necrosis factor-alpha, and brain-derived neurotrophic factor have been associated with various cachectic conditions. Controversy has focused on the requirement of increased cytokine concentrations in the circulation or other body fluids (e.g., cerebrospinal fluid) to demonstrate cytokine involvement in cachexia-anorexia. Cytokines, however, also act in paracrine, autocrine, and intracrine manners, activities that cannot be detected in the circulation. In fact, paracrine interactions represent a predominant cytokine mode of action within organs, including the brain. Data show that cytokines may be involved in cachectic-anorectic processes by being produced and by acting locally in specific brain regions. Brain synthesis of cytokines has been shown in peripheral models of cancer, peripheral inflammation, and during peripheral cytokine administration; these data support a role for brain cytokines as mediators of neurologic and neuropsychiatric manifestations of disease and in the brain-to-peripheral communication (e.g., through the autonomic nervous system). Brain mechanisms that merit significant attention in the cachexia-anorexia syndrome are those that result from interactions among cytokines, peptides/neuropeptides, and neurotransmitters. These interactions could result in additive, synergistic, or antagonistic activities and can involve modifications of transducing molecules and intracellular mediators. Thus, the data show that the cachexia-anorexia syndrome is multifactorial, and understanding the interactions between peripheral and brain mechanisms is pivotal to characterizing the underlying integrative pathophysiology of this disorder.

Anorexia↗

Intratumoral injection of oligonucleotides to the NF kappa B binding site inhibits cachexia in a mouse tumor model.

Cancer cachexia, characterized by anorexia, weight loss and progressive tissue wasting, has been postulated to be mediated by various cytokines. However, the precise mechanism of cachexia induction is not fully explained. We have developed synthetic double-stranded oligodeoxynucleotides (ODN) as 'decoy' cis-elements that block the binding of nuclear factors to promoter regions of targeted genes, resulting in the inhibition of gene transactivation in vivo as well as in vitro. This novel molecular strategy could be useful for treating a broad range of human diseases including cancer. In this study, we injected decoy ODN targeting the transcriptional factor, NF-kappa B (NF kappa B) binding cis-elements, which are essential for transactivation of gene expression of cytokines, directly into tumors of adenocarcinoma colon26 in mice, in order to examine whether or not cachexia is alleviated by inhibiting the action of cytokines. Tumor growth was not affected by transfection of NF kappa B decoy ODN as compared with scrambled decoy ODN. Nevertheless, transfection of NF kappa B decoy, but not scrambled decoy, ODN resulted in attenuation of the reductions in body weight, epididymal fat, gastrocnemius muscle mass and food intake, which were induced by the tumor presence. Interleukin 6 mRNA in the tumor was also markedly decreased by the transfection of NF kappa B decoy ODN. It is known that the transcriptional factor E2F plays a pivotal role in the coordinated transactivation of cell cycle regulatory genes. Therefore, we hypothesized that the introduction of synthetic double-stranded DNA with high affinity for E2F in vivo as 'decoy' cis-elements might inhibit the tumor growth of colon26, resulting in turn in inhibition of cachexia induction. However, injection of E2F decoy ODN failed to inhibit tumor growth and cachexia induction, as compared with mismatched decoy ODN. Overall, the present study demonstrated that cachexia induced by adenocarcinoma colon26 was inhibited by blocking of NF kappa B, using a novel molecular decoy strategy, without an effect on tumor growth, and also that tumor growth and cachexia induction in the colon26 model were not affected by E2F decoy ODN. These results suggest that cytokines regulated by NF kappa B may play a pivotal role in the induction of cachexia by colon26, providing a new therapeutic strategy for cancer cachexia.

Adenocarcinoma↗

Mechanisms of cancer cachexia.

It is currently hypothesized that the mechanisms of cancer cachexia involve the host's production of inflammatory cytokines, which in turn orchestrate a series of complex interrelated steps that ultimately lead to a chronic state of wasting, malnourishment, and death (see Fig. 1). The metabolic changes seen in the tumor-bearing host are similar, but not identical, to those seen in sepsis and inflammation and appear to result from a generalized response of the host to the stimulus of invasion--the tumor. Although there are likely to be several humoral factors, of either host or tumor origin (see Fig. 1), involved in cancer cachexia, recombinant DNA methodology has provided sufficient amounts of only a few cytokines to enable careful investigation of their cachectic potential. TNF/cachectin has been most extensively studied and appears to play a clear role, because administration of low-dose continuous or escalating doses simulates changes associated with cancer cachexia. In addition, these cachectic changes have been blocked by a specific antisera. IL-1, IL-6, and interferon-gamma all have potential as mediators of cancer cachexia and more work is clearly indicated. It is possible that, given our current understanding of the mechanisms of cancer cachexia, it can be theorized that TNF, which causes many of the manifestations of cancer cachexia, and IL-1 are released by macrophages in response to tumor (see Fig. 1). Interferon-gamma appears to potentiate these effects and may also be necessary for the complete syndrome of cancer cachexia. IL-6 probably is released as another mediator, principally mediating the acute phase response seen in cancer cachexia. Other factors are certain to be involved. Further study into the mechanisms and possible treatment of cancer cachexia is needed, because a large proportion of cancer patients who are incurable by current therapies continue to suffer from this lethal wasting diathesis. Furthermore, specific strategies to reverse the cachectic changes associated with cancer will likely improve antitumor treatment.

Animals↗

Studies on apoptosis and fibrosis in skeletal musculature: a comparison of heart failure patients with and without cardiac cachexia.

Apoptosis has been found in skeletal muscles of patients with chronic heart failure (CHF) and has been associated with exercise intolerance. In CHF, cachexia is characterized by neurohormonal activation and muscle wasting. Neurohormonal activation can lead to cell death and fibrosis. The purpose of the study was to determine the severity of apoptosis and fibrosis in skeletal muscles of patients with CHF and cachexia and its relationship to exercise intolerance in these patients. Skeletal muscle biopsies of 21 patients with CHF (eight with cachexia) and four healthy controls of similar age have been studied by in situ end labeling (ISEL) for apoptosis and by the Picrosirius Red technique for collagen. Apoptosis in skeletal muscles was detected by ISEL in 52% of the patients with CHF (11 out of 21) and in none of the controls. CHF patients with apoptosis-positive skeletal muscles had impaired exercise tolerance (peak oxygen consumption 11.4+/-5.7 vs. 16.91+/-6.6, P=0.029). Increased collagen was detected by Picrosirius Red in eight out of 21 patients with CHF and in none of the controls. Increased collagen (fibrosis) was detected in six out of eight patients with cachexia and in two out of 13 patients without cachexia (P=0.01). Peak oxygen consumption and apoptosis were similar in cachectic and non-cachectic patients. Thus, the skeletal musculature of patients with cardiac cachexia is characterised by the presence of fibrosis. Apoptosis was not found to be more frequent in cachectic CHF patients. Our data support the hypothesis that cachexia contributes by a different mechanism to skeletal muscle myopathy of CHF patients and different mechanisms are implicated in deterioration of exercise tolerance and progression to cardiac cachexia.

Aged↗

Cytokines and cachexia.

Prolonged production of cytokines associated with cancer and chronic infections, and other long-term immune reactions is increasingly recognized as a main causal factor of the often severe signs and symptoms that accompany these diseases: weight loss, anorexia, and metabolic breakdown termed cachexia. The cytokine that initially was held responsible for causing these changes was tumor necrosis factor (TNF). However, from various studies it has become clear that the action of TNF can only be understood in the context of simultaneous presence of other cytokines, some of which have activities that are at the least equally important as TNF in bringing about cachexia. This review summarizes the experimental evidence for the involvement of cytokines in the pathogenesis of cachexia. Indirect evidence comes from the observation that cachexia can be induced in animals by repeated injections of cytokines or by inoculation of cytokine-producing cells. Thus, cachexia has been described in mice inoculated with tumor cells carrying and expressing genes for either TNF, interleukin-6 (IL-6), leukemia inhibitory factor (LIF), ciliary neurotrophic factor (CNTF) and interferon-gamma (IFN-gamma). More direct evidence is provided by the observations that cachexia in experimental animal models can be mitigated by administration of specific antagonists of cytokines. These latter type of studies revealed that cachexia can rarely, if ever, be attributed to one single cytokine but rather to a set of cytokines that work in concert in cachexia. A pool of anticytokine antibodies or other cytokine inhibitors might, therefore, be considered as a potential intervention for the treatment of cachectic patients, but this approach may induce immunosuppression, and, therefore, danger exists that such treatment may benefit the infectious agent or tumor.

Animals↗

Cancer cachexia.

Cachexia is a common problem in the clinical management of cancer patients, particularly those with solid tumors. Cachexia is most obviously manifested as weight loss with massive depletion of both adipose tissue and muscle mass, and death is probably due to loss of lean body tissue. Not only is the survival time shorter in patients with cachexia, but the frequency of response to chemotherapy is also significantly reduced. Although anorexia frequently accompanies cachexia, attempts to halt or reverse cachexia by nutritional repletion have not been successful. This suggests that cachexia is due to metabolic abnormalities produced by the tumor in addition to the underlying anorexia. In some patients weight loss is associated with an increased relative energy expenditure possibly through an elevated adrenergic state. Several factors have been postulated as mediators of cancer cachexia and can be divided into two groups. (i) Materials with hormone-like characteristics which result in direct catabolism of host tissues. (ii) Cytokines which cause alterations in host metabolism indirectly. Included in group (i) are the conventional catabolic hormones and a lipid mobilizing factor (LMF) produced by tumors, which causes direct breakdown of adipose tissue. Included in group (ii) are tumor necrosis factor-alpha, interleukin-6, interferon-gamma and leukaemia inhibitory factor. The materials appear to influence adipose tissue indirectly through an inhibition of lipoprotein lipase. Reversal of cachexia has been achieved by two groups of agents. (i) Those stimulating food intake, e.g. megestrol acetate. (ii) Those directly inhibiting the LMF, e.g. eicosapentaenoic acid. While agents in group (i) can cause tumor growth stimulation, those in group (ii) act as tumor growth inhibitors. This latter results suggests that the products of catabolism of host tissues may be important for tumor growth and provides a new avenue for chemotherapeutic intervention.

Animals↗

What we have learned about cachexia in gastrointestinal cancer.

It is appreciated widely by clinicians that significant malnutrition accompanies malignant processes in approximately 50% of patients and eventually leads to severe wasting which accounts for approximately 30% of cancer-related deaths overall, 30-50% of deaths in patients with gastrointestinal tract cancers, and up to 80% of deaths in patients with advanced pancreatic cancer. The body wasting known as cancer cachexia is a complex syndrome characterized by progressive tissue depletion and decreased nutrient intake that is manifested clinically as inexplicable, recalcitrant anorexia and inexorable host weight loss. Decreased nutritional intake, increased metabolic expenditure and dysfunctional metabolic processes, including hormonal and cytokine-related abnormalities, all appear to play roles in the development of cancer cachexia. Although this condition of advanced protein-calorie malnutrition, sometimes described as the cancer anorexia-cachexia syndrome, is not entirely understood, it appears to be multifactorial, is a major cause of morbidity and mortality in cancer patients, and ultimately leads to death. Therapeutic interventions have met with little success, and, regardless of tremendous efforts throughout the decades, the exact nature of the mediators responsible for cancer cachexia remain elusive. The pathogenesis of cancer cachexia appears to be related to proinflammatory cytokines, alterations in the neuroendocrine axis and tumor-derived catabolic factors. Despite trials of conventional and/or aggressive nutritional support by a myriad of feeding techniques, patients with cancer cachexia have failed to gain consistent significant benefits in terms of weight gain, functional ability, quality of life or survival. Additionally, attempts to ameliorate the abnormal clinical and metabolic features of cancer cachexia with a variety of pharmacologic agents have met with only limited success. Either until cancer of the gastrointestinal tract can be cured or until it is possible to identify the exact causes and mechanisms of the cancer cachexia syndrome, the most realistic and practical options currently are directed toward minimizing adverse gastrointestinal side effects or complications of the malignant process and/or therapy, as well as increasing appetite, food intake and nutrient utilization in an effort to enhance quality of life and improve survival.

Appetite↗

The effects of ageing, cachexia and neoplasms on striated muscle. Quantitative histological and histochemical observations on an autopsy material.

The effects of ageing, cachexia and neoplasms on striated muscle were examined in histological sections of an autopsy material. Paraffin sections were examined from four separate muscles of 30 previously healthy subjects who died suddenly, from eight cases with cachexia and from 16 cases with cachexia and neoplasms. In addition, ATP-ase stained cryostat sections were examined from two muscles from most of the cases. All the sections were evaluated with regard to atrophy, myopathic changes and fibre type grouping. Furthermore, the exact size of 100 fibres of each type was determined in the enzyme stained sections. Myopathic changes were found in a few muscles, mainly in the normal cases. They were considered incidental findings without clinical significance. Fibre type grouping could not be evaluated in the anterior tibial muscle because large clusters of the same fibre type occur normally in this muscle. In the biceps brachii only two normal cases and none of the cachectic cases showed fibre type grouping. A moderate small grouped muscle fibre atrophy was found in normal cases with increasing age. The cases with cachexia showed a marked small grouped atrophy which involved both fibre types. There were only small and uncertain differences between cases with cachexia and tumours and those with cachexia alone. Thus, no changes were observed which could be ascribed to tumours alone. The small grouped atrophy in ageing and cachexia resembled that seen in denervation atrophy but the exact mechanism of the changes remains obscure.

Adenosine Triphosphatases↗

Improvement by eicosanoids in cancer cachexia induced by LLC-IL6 transplantation.

Cachexia frequently occurs in the late stages of cancer, and is difficult to manage. We previously reported that interleukin-6 (IL-6) cDNA transfection into Lewis lung carcinoma (LLC-IL6) induced cachexia-like symptoms in C57BL/6 mice. This was thought to be a useful experimental model of cancer cachexia. We have examined the effects of two eicosanoids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), in order to evaluate whether they could relieve cachexia. LLC-IL6-bearing animals were divided into three treatment groups receiving DHA, EPA or water as the control; 80-microliter samples of these compounds (purity > 95%) were administered orally by catheter daily starting 7 days after tumor transplantation. Tumor growth curves were similar in the three groups. There were no differences in water or food intake in the three groups. However, body weight, a marker of cachexia, was significantly higher in treated mice than in the control group. Sixteen days after tumor transplantation, the mean body weight was 17.45 g (P < 0.05), 17.2 g and 16.41 g in the groups receiving DHA, EPA and water respectively. The eicosanoids did not affect serum levels of IL-6. Ubiquitination of muscle protein, a marker of proteolysis coupled to cachexia, was compared in LLC-IL6- and LLC-transplanted mice. The eicosanoids prevented the ubiquitination of approximately 180 kDa protein. These results suggest that eicosanoids may prevent the cachexia mediated by IL-6.

Animals↗