Interleukin 1, tumour necrosis factor-alpha (cachectin) and the pathogenesis of cancer cachexia

IL-6 promotes tumor growth through immune evasion but is dispensable for cachexia

Various cytokines have been implicated in cancer cachexia. One such cytokine is IL-6, deemed as a key cachectic factor in mice inoculated with colon carcinoma 26 (C26) cells, a widely used cancer cachexia model. Here we tested the causal role of IL-6 in cancer cachexia by knocking out the IL-6 gene in C26 cells. We found that the growth of IL-6 KO tumors was dramatically delayed. More strikingly, while IL-6 KO tumors eventually reached the similar size as wild-type tumors, cachexia still took place, despite no elevation in circulating IL-6. In addition, the knockout of leukemia inhibitory factor (LIF), another IL-6 family cytokine proposed as a cachectic factor in the model, also affected tumor growth but not cachexia. We further showed an increase in the infiltration of immune cell population in the IL-6 KO tumors compared with wild-type controls and the defective IL-6 KO tumor growth was rescued in immunodeficient mice while cachexia was not. Thus, IL-6 promotes tumor growth by facilitating immune evasion but is dispensable for cachexia.

IL-6 is dispensable for causing cachexia in the colon carcinoma 26 model

Various cytokines have been implicated in cancer cachexia. One such cytokine is IL-6, which has been deemed a key cachectic factor in mice inoculated with the colon carcinoma 26 (C26) cells, one of the most widely used models of cancer cachexia. Here to test the causal role of IL-6 in cancer cachexia, we used CRISPR/Cas9 editing to knock out IL-6 in C26 cells. We found that growth of IL-6 KO C26 tumors was dramatically delayed. Most strikingly, while IL-6 KO tumors eventually reached the similar size as wild-type tumors, cachexia still took place, despite no elevation in circulating IL-6. We further showed an increase of immune cell populations in IL-6 KO tumors and the defective IL-6 KO tumor growth was rescued in immunodeficient mice. Thus, our results invalidated IL-6 as a necessary factor for causing cachexia in the C26 model and revealed instead its important role in regulating tumor growth via immune suppression.

Poor dental condition is a factor of imbalance of the nutritional status at the outset of management of head and neck cancer

OBJECTIVES

To determine whether deterioration of dental condition at the outset of management of head and neck cancer (HNC) is a nutritional risk and whether social deprivation is a cause of the poor dental condition observed in HNC patients.

MATERIAL AND METHODS

A nutritional assessment form (NAF) and the Nutrition Risk Index (NRI) were used to standardize the nutritional status of 108 patients at the outset of management of HNC (2017-2019). The NAF includes assessment of weight loss over the past 3 months, the amount and difficulty of food intake, and the presence of digestive disorders. Dental condition was assessed by the decayed, filled, and missing teeth acopre (DFM) index and the masticatory coefficient (MC). Dental status and social deprivation were correlated with the EPICES score.

RESULTS

A correlation was found between the extent of weight loss and dental condition. The MC was higher in absence of weight loss (46% vs. 27%, p = 0.03) and the DMF lower when weight loss was less than 5% (22.3 vs. 26.9 if > 5% loss of weight, p = 0.005). No correlation was found between dental status and nutritional status. Social deprivation was associated with a lower MC (26% vs. 50%, p < 0.001).

CONCLUSION

Dental condition is a risk factor for weight loss at the outset of management of HNC but is not a determinant of nutritional status. Clinical relevance Dental condition is no longer considered simply as a source of potential complications after radiotherapy but also as an important factor for nutritional status.

The Pathway to Cancer Cachexia: MicroRNA-Regulated Networks in Muscle Wasting Based on Integrative Meta-Analysis

Cancer cachexia is a multifactorial syndrome that leads to significant weight loss. Cachexia affects 50%-80% of cancer patients, depending on the tumor type, and is associated with 20%-40% of cancer patient deaths. Besides the efforts to identify molecular mechanisms of skeletal muscle atrophy-a key feature in cancer cachexia-no effective therapy for the syndrome is currently available. MicroRNAs are regulators of gene expression, with therapeutic potential in several muscle wasting disorders. We performed a meta-analysis of previously published gene expression data to reveal new potential microRNA-mRNA networks associated with muscle atrophy in cancer cachexia. We retrieved 52 differentially expressed genes in nine studies of muscle tissue from patients and rodent models of cancer cachexia. Next, we predicted microRNAs targeting these differentially expressed genes. We also include global microRNA expression data surveyed in atrophying skeletal muscles from previous studies as background information. We identified deregulated genes involved in the regulation of apoptosis, muscle hypertrophy, catabolism, and acute phase response. We further predicted new microRNA-mRNA interactions, such as miR-27a/Foxo1, miR-27a/Mef2c, miR-27b/Cxcl12, miR-27b/Mef2c, miR-140/Cxcl12, miR-199a/Cav1, and miR-199a/Junb, which may contribute to muscle wasting in cancer cachexia. Finally, we found drugs targeting MSTN, CXCL12, and CAMK2B, which may be considered for the development of novel therapeutic strategies for cancer cachexia. Our study has broadened the knowledge of microRNA-regulated networks that are likely associated with muscle atrophy in cancer cachexia, pointing to their involvement as potential targets for novel therapeutic strategies.

IL-10 Signaling Remodels Adipose Chromatin Architecture to Limit Thermogenesis and Energy Expenditure

Signaling pathways that promote adipose tissue thermogenesis are well characterized, but the limiters of energy expenditure are largely unknown. Here, we show that ablation of the anti-inflammatory cytokine IL-10 improves insulin sensitivity, protects against diet-induced obesity, and elicits the browning of white adipose tissue. Mechanistic studies define bone marrow cells as the source of the IL-10 signal and adipocytes as the target cell type mediating these effects. IL-10 receptor alpha is highly enriched in mature adipocytes and is induced in response to differentiation, obesity, and aging. Assay for transposase-accessible chromatin sequencing (ATAC-seq), ChIP-seq, and RNA-seq reveal that IL-10 represses the transcription of thermogenic genes in adipocytes by altering chromatin accessibility and inhibiting ATF and C/EBPβ recruitment to key enhancer regions. These findings expand our understanding of the relationship between inflammatory signaling pathways and adipose tissue function and provide insight into the physiological control of thermogenesis that could inform future therapy.

Piperine inhibit inflammation, alveolar bone loss and collagen fibers breakdown in a rat periodontitis model

BACKGROUND AND OBJECTIVE

Piperine exhibits anti-inflammatory activity, and has a long history of medicinal use. The objective of this study was to investigate the protective effects of piperine on inflammation, alveolar bone and collagen fibers in experimental periodontitis. We evaluated the related expression of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, matrix metalloproteinase (MMP)-8 and MMP-13 to enhance insight into these effects.

MATERIAL AND METHODS

Thirty-two Wistar rats were divided into four groups of eight animals each: control group, periodontitis group, periodontitis plus 50 mg/kg piperine group and periodontitis plus 100 mg/kg piperine group. Histopathologic changes were detected by hematoxylin and eosin staining. Alveolar bone loss and trabecula microstructures were evaluated by micro-computed tomography. Changes in collagen fibers were assessed by picrosirius red staining. Western blot analysis was conducted to determine the levels of IL-1β, TNF-α, MMP-8 and MMP-13.

RESULTS

Piperine clearly inhibited alveolar bone loss and reformed trabecula microstructures in a dose-dependent manner. Histological staining showed that piperine significantly reduced the infiltration of inflammation in soft tissues. Both doses of piperine limited the fractions of degraded areas in collagen fibers. Piperine (100 mg/kg) significantly downregulated the expressions of IL-1β, MMP-8 and MMP-13 in periodontitis, but not that of TNF-α.

CONCLUSION

Piperine displays significantly protective effects on inflammation, alveolar bone loss, bone microstructures and collagen fiber degradation in experimental periodontitis. The effects may be ascribed to its inhibitory activity on the expressions of IL-1β, MMP-8 and MMP-13.

Why do anti-inflammatory therapies fail to improve insulin sensitivity?

Chronic inflammation occurs in obese conditions in both humans and animals. It also contributes to the pathogenesis of type 2 diabetes (T2D) through insulin resistance, a status in which the body loses its ability to respond to insulin. Inflammation impairs insulin signaling through the functional inhibition of IRS-1 and PPARγ. Insulin sensitizers (such as rosiglitazone and pioglitazone) inhibit inflammation while improving insulin sensitivity. Therefore, anti-inflammatory agents have been suggested as a treatment strategy for insulin resistance. This strategy has been tested in laboratory studies and clinical trials for more than 10 years; however, no significant progress has been made in any of the model systems. This status has led us to re-evaluate the biological significance of chronic inflammation in obesity. Recent studies have consistently asserted that obesity-associated inflammation helps to maintain insulin sensitivity. Inflammation stimulates local adipose tissue remodeling and promotes systemic energy expenditure. We propose that these beneficial activities of inflammation provide an underlying mechanism for the failure of anti-inflammatory therapy in the treatment of insulin resistance. Current literature will be reviewed in this article to present evidence that supports this viewpoint.

Myeloid-derived suppressor cells in cancer cachexia syndrome: a new explanation for an old problem

Cachexia accompanies many chronic inflammatory diseases, including cancer. Lean tissue wasting is only one component of the cancer cachexia response, which also includes anemia, anorexia, a hepatic acute phase protein response, and increased susceptibility to secondary infections. The etiologies of cancer cachexia are multifactorial and include an overproduction of inflammatory mediators, including cytokines produced by inappropriate activation of innate immunity. However, anticytokine therapies have generally not been seriously considered for cancer cachexia, in large part because of the overlapping activities of several inflammatory cytokines and the inability to prospectively identify the contributions of individual mediators. In contrast, recent evidence has focused on an immature myeloid cell population that expands dramatically in the tumors and secondary lymphoid organs of animals with some actively growing tumors. These immature GR-1(+)CD11b(+) cells are metabolically active and secrete large quantities of inflammatory cytokines and chemokines with the potential to produce cachexia. Their expansion is temporally associated with the development of cachexia. Future studies are required to determine whether therapeutic efforts intended to block the expansion of these cells can prevent the lean tissue wasting that accompanies active tumor growth.

Evidence that lipopolysaccharide-induced anorexia depends upon central, rather than peripheral, inflammatory signals

Systemic inflammatory stimuli cause anorexia and weight loss by disrupting the physiological regulation of energy balance. Mice lacking MyD88, an intracellular mediator of signal transduction activated by Toll-like receptor 4 or IL-1beta receptors, are resistant to anorexia induced by the bacterial endotoxin lipopolysaccharide (LPS), despite a significant circulating cytokine response. Thus, we hypothesized that induction of a peripheral inflammatory response is insufficient to cause LPS-induced anorexia when MyD88 signaling in the central nervous system and other tissues is absent. To test this hypothesis, we used bone marrow transplantation (BMT) to determine if LPS-induced anorexia can be restored to MyD88-deficient mice by reconstituting their bone marrow with wild-type (WT) immune cells. We found that restoring WT circulating immune cells to mice lacking MyD88 conferred only a mild, short-lived anorexia in response to LPS, such that food intake was fully normalized by 20 h post injection (LPS 4.1 +/- 0.5 g vs. vehicle 4.3 +/- 0.3 g), whereas LPS-induced anorexia was profound and sustained in WT controls after either autologous BMT or sham BMT. Similarly, LPS-mediated induction of hypothalamic mRNA encoding IL-1beta and TNFalpha was robust in both WT control groups but was absent in chimeric MyD88 mice, despite comparable peripheral inflammatory responses across the three groups. We conclude that LPS reduces food intake via a mechanism dependent on MyD88 signaling within brain and/or other tissues and that in the absence of this effect, robust stimulation of circulating immune cells cannot induce sustained anorexia.

Capecitabine improves cancer cachexia and normalizes IL-6 and PTHrP levels in mouse cancer cachexia models

PURPOSE

To clarify the potential of parathyroid hormone-related protein (PTHrP) and interleukin-6 (IL-6) as cachectic factors in a colon 26 model and the effects of capecitabine on cancer cachexia as determined by plasma levels of IL-6 and PTHrP and body weight loss.

METHODS

From two colon 26 sublines-cancer cachectic clone20 and non-cachectic clone5 plasma levels of PTHrP protein and mRNA expression levels in tumor tissues were compared. An IL-6 neutralizing antibody, a PTHrP neutralizing antibody, and capecitabine were administered into mice bearing clone20 and their anticachectic effects evaluated.

RESULTS

The plasma level of PTHrP protein in mice bearing clone20 was higher than that in mice bearing clone5. The expression level of PTHrP mRNA was 49-fold higher in tumor tissues of clone20 than of clone5, according to GeneChip analysis. PTHrP antibody as well as IL-6 antibody suppressed wasting of the body and gastrocnemius and adipose tissue weights. PTHrP antibody suppressed the induction of hypercalcemia but not hypoglycemia or elevation of IL-6, whereas IL-6 antibody suppressed the induction of hypoglycemia but not hypercalcemia or elevation of PTHrP. Capecitabine, a fluorinated pyrimidine anticancer agent, improved body wasting of mice bearing clone20 at a low dose with no reduction of tumor volume. Furthermore, capecitabine lowered the levels of PTHrP and IL-6 in plasma and suppressed hypoglycemia and hypercalcemia in this model. Capecitabine also showed anticachectic effects on cachexia in a cancer model induced by human cervical cancer cell line Y (also known as Yumoto).

CONCLUSIONS

PTHrP and IL-6 were found to be factors in the development of cachexia in a colon 26 cancer model, and capecitabine improved cancer cachexia by suppressing the plasma levels of IL-6 and PTHrP in colon 26 and Y cachectic models.

Characterization of a Human Homologue of Proteolysis-Inducing Factor and Its Role in Cancer Cachexia

Cachexia is an important cause of secondary morbidity and mortality in patients with cancer. Previous studies have suggested that cancer-associated cachexia may be due in part to tumor-specific production and secretion of a glycosylated peptide, proteolysis-inducing factor, originally identified in a murine cancer cachexia model. We report here the cloning of a human cDNA that generates a peptide having high-sequence homology to this proteolysis-inducing factor. Constitutive expression of human proteolysis-inducing factor is low or absent in most normal human tissues but appears to be elevated in some human tumors. Stable forced expression of human proteolysis-inducing factor in multiple murine and human cell lines results in a secreted protein, but no glycosylation of the protein is detected. In addition, tumor xenografts engineered to overexpress human proteolysis-inducing factor protein do not induce cachexia in vivo. These findings raise important questions as to potential cross-species differences in protein sequence and processing of murine proteolysis-inducing factor and human proteolysis-inducing factor, as well as the nature of the relationship between human proteolysis-inducing factor and the development of cancer cachexia.

Potential of p38 MAP kinase inhibitors in the treatment of cancer

The involvement of chronic inflammation in tumor development and progression is reviewed. Based on the natural history of certain diseases and epidemiology studies, a strong association has been established between particular chronic inflammatory conditions and eventual tumor appearance. Solid tumors require a stroma for their growth and recruit macrophages to synthesize essential growth and angiogenic factors that they do not have the capacity to produce. The microenvironment of the local host tissue appears to be an active participant in exchanging cytokines and enzymes with tumor cells that modify the local extracellular matrix, stimulate migration, and promote tumor angiogenesis, proliferation and survival. The role of p38 MAP kinase as a therapeutic target for treating cancer is discussed.

Lack of effects by tricyclic antidepressant and serotonin inhibitors on anorexia in MCG 101 tumor-bearing mice with eicosanoid-related cachexia

OBJECTIVES

Anorexia is a major clinical problem in large number of patients with advanced cancer disease. Serotonergic mechanisms are assumed to play a role in the process of feeding behavior during normal and pathologic circumstances, which may also involve cancer anorexia according to previous experimental and clinical studies.

METHODS

In the present study, we evaluated the effect of the tricyclic antidepressants desipramine (7.5 mg x kg(-1) x d(-1), intraperitoneal) and imipramine (2 to 5 mg. kg(-1) x d(-1), intraperitoneal) the serotonin synthesis inhibitor para-chlorophenylalanine (300 mg x kg(-1) x d(-1), intraperitoneal), the serotonin receptor 5-HT(2C) antagonist cyproheptadine (5 mg x kg(-1) x d(-1), intraperitoneal) and the selective serotonin reuptake inhibitor citalopram (20 mg x kg(-1) x d(-1), intraperitoneal) on anorexia in MCG-101 tumor-bearing mice, a model with significant anorexia and cachexia sensitive to cyclooxygenase inhibition. Also, MCG 101-bearing mice develop well-recognized alterations in brain tryptophan/serotonin metabolism as increased Trp, 5-HPT, and 5-HIAA during tumor progression.

RESULTS

Daily provision of desipramine, imipramine, para-chloropheylalanine, cyproheptadine, and citalopram at doses that cause behavioral and metabolic alterations in normal mice did not alter food intake or body weight in tumor-bearing and healthy control mice. Also, the treatments did not decrease elevated plasma concentrations of interleukin-6 and prostaglandin E(2) in the tumor-bearing mice.

CONCLUSIONS

Thus, our results do not support previous observations that serotonin metabolism itself is a major factor behind anorexia in tumor-bearing animals in general. Rather, other mechanisms, such as eicosanoid and nitric oxide-dependent pathways, seem to be more important for induction of anorexia along tumor progression in the present model.

Depressive and anxiety symptoms in the early puerperium are related to increased degradation of tryptophan into kynurenine, a phenomenon which is related to immune activation

There is now some evidence that i) the availability of plasma tryptophan, the precursor of serotonin, is significantly lower in pregnant women at the end of term and the first few days after delivery than in nonpregnant women; and ii) both pregnancy and the early puerperium are accompanied by activation of the inflammatory response system. The aims of the present study were to examine the effects of pregnancy and delivery on plasma kynurenine, a major tryptophan catabolite synthesized after induction of indoleamine-2, 3 dioxygenase (IDO) by pro-inflammatory cytokines. We measured plasma kynurenine and tryptophan and immune markers, such as serum interleukin-6 (IL-6), IL-8 and the leukemia inhibitory factor-receptor (LIF-R) in healthy, nonpregnant and pregnant women at the end of term and one and three days after delivery. Plasma kynurenine was significantly lower in pregnant women at the end of term than in nonpregnant women, findings which may be attributed to lower plasma tryptophan at the end of term. The kynurenine/tryptophan (K/T) quotient was significantly higher in the pregnant women at the end of term and in the early puerperium than in nonpregnant women. In the early puerperium there was a significant increase in plasma kynurenine and the K/T quotient. The increases in plasma kynurenine and the K/T quotient were significantly more pronounced in women whose anxiety and depression scores significantly increased in the puerperium. The changes from the end of term to the early puerperium in plasma kynurenine and the K/T quotient were significantly related to those in the immune markers. It is concluded that 1) lower plasma kynurenine at the end of term is the consequence of lower plasma tryptophan; 2) the increased K/T quotient at the end of term and in the early puerperium indicates inflammation-induced degradation of tryptophan along the kynurenine pathway; and 3) that depressive and anxiety symptoms in the early puerperium are (causally) related to an increased catabolism of tryptophan into kynurenine, a phenomenon which probably results from immune activation.

Eradication of Helicobacter pylori infection induces an increase in body mass index

BACKGROUND

The relationship between H. pylori infection and body mass indices is controversial.

AIM

To investigate the relationship between H. pylori infection and body indices, and to examine the effect of H. pylori eradication therapy on body indices.

METHODS

Nine-hundred and thirty-two employees of an industrial corporation were examined for H. pylori infection and body mass indices. Three hundred and two H. pylori-positive cases diagnosed with chronic gastritis by upper gastrointestinal endoscopy or radiography underwent eradication therapy. Body mass indices, serum total cholesterol levels and symptom scores were obtained before and at 12 months after eradication therapy.

RESULTS

There was no significant difference in body weight, body mass index (BMI) or serum total cholesterol level between the H. pylori-positive and H. pylori-negative groups. However, body weight and BMI increased significantly 12 months after eradication of H. pylori infection. In contrast, there was no significant difference in body weight and BMI 12 months after eradication therapy in the non-eradication group. Serum total cholesterol levels did not change after eradication therapy in either the eradication or non-eradication groups.

CONCLUSION

Eradication of H. pylori infection induced an increase in BMI in industrial workers with chronic gastritis in Japan.

Involvement of parathyroid hormone-related protein in experimental cachexia induced by a human lung cancer-derived cell line established from a bone metastasis specimen

Cachexia often causes deterioration in the quality of life in cancer patients; however, its mechanism remains poorly understood. Cachexia has often been observed in experimental animals with bone metastases, and parathyroid hormone-related protein (PTHrP) plays an important role in the formation of such metastases. We therefore investigated the possible involvement of PTHrP in an experimental cachexia model using human lung-cancer cells (HARA-B). HARA-B cells produce a high amount of PTHrP but no TNF-alpha, IL-6 or leukemia inhibitory factor. The s.c. inoculation of HARA-B cells into nude mice caused reductions in body weight, adipose tissue weight, muscle weight and serum glucose levels. Serum levels of calcium and PTHrP increased. Neutralization of PTHrP with antibody caused rapid weight gain along with a rapid decrease in serum calcium levels. Our findings suggest that PTHrP plays an important role in the development of cancer cachexia. PTHrP therefore is a possible target molecule for the treatment of cancer cachexia.

Differential gene expression in a murine model of cancer cachexia

Murine adenocarcinoma 16 (MAC16) tumors and cell lines induce cachexia in NMRI nude mice, whereas histologically similar MAC13 tumors do not. After confirming these findings in BALB/c nude mice, we demonstrated that this tissue wasting was not related to decreased food intake or increased total body oxidative metabolism. Previous studies have suggested that MAC16's cachexigenic properties may involve the production of tumor-specific factors. We therefore screened for genes having increased expression in the MAC16 compared with the MAC13 cell line by performing hybridization to a murine cDNA expression array, by generation and comparison of cDNA libraries from each cell line, and by PCR-based subtractive hybridization. Northern blot hybridization was performed to confirm differences in transcript expression. Transcripts encoding insulin-like growth factor binding protein-4, cathepsin B, ferritin light and heavy chain, endogenous long-terminal repeat sequences, and a viral envelope glycoprotein demonstrated increased expression in the MAC16 cell line. The roles of a number of these genes in known metabolic pathways identify them as potential participants in the induction of cachexia.

Role of cytokines in cancer cachexia in a murine model of intracerebral injection of human tumours

To study the role of cytokines that are relevant in cancer cachexia syndrome due to intracerebral tumours, mice were injected with human A431 epidermoid carcinoma, OVCAR3 ovarian carcinoma and GBLF glioma cells comparing intracerebral (i.c.) and systemic (i.p. or s.c.) routes of implantation. Anorexia and weight loss developed within 7-10 days in mice injected i.c. with A431 or OVCAR3 cells well before a large tumour developed, while i.c.-injected GBLF cells did not induce cachexia until day 20, when the tumour was large. By contrast, mice injected i.p. or s.c. developed tumours without evidence of anorexia. Thus, intracerebrally-growing A431 and OVCAR3 resulted in cancer cachexia independent of tumour mass, and we investigated their cytokine pattern. Serum levels of murine and human cytokines are not predictive of cancer cachexia development. Reverse-transcriptase polymerase chain reaction (RT-PCR) analysis revealed in the brain of i.c.-injected A431 tumour-bearing mice expression of human interleukin-(IL-)1alpha, IL-1beta and LIF in all samples and IL-6 in two of four samples while in i.c.-injected OVCAR3 tumour-bearing animals IL-6, and LIF were detected in all samples and tumour necrosis factor-alpha (TNFalpha) in two of four samples. Only LIF was expressed in brains of mice injected with GBLF cells. Murine IL-6 was increased only in the brains of A431-bearing mice. Only mice injected i.c. simultaneously with a monoclonal antibody (mAb) directed against the murine IL-6 receptor and OVCAR3 cells, but not those with mAb and A431 cells, showed a significant increase in survival time with a partial and temporary attenuation of cachexia symptoms. These results suggest that IL-6 in OVCAR3 model may be important cachectogenic factor when centrally released by even a limited number of tumour cells.

Identification of genetic loci associated with paralysis, inflammation and weight loss in mouse experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE), a model for human multiple sclerosis, is an inducible inflammatory and demyelinating disease of the central nervous system (CNS). Susceptibility to this disease is heritable and is demonstrated by the development of an ascending paralysis accompanied by a loss in body wt 2-3 weeks following immunization with proteins derived from CNS myelin. In a previous genetic analysis of susceptibility to EAE in a cross between susceptible SJL/J mice and resistant B10.S mice, we found suggestive evidence of linkage with disease susceptibility at the telomeric end of chromosome 2 and in the central region of chromosome 3. To define these associations more precisely and to investigate the genetic factors controlling measurable phenotypes of EAE, we performed a new analysis with a larger number of mice. The results now indicate that the chromosome 2 locus significantly influences EAE-related weight loss (P = 6.7 x 10(-5)) and that the chromosome 3 locus is linked with the development of paralysis. In addition, an intriguing inheritance pattern was revealed in which female backcross mice generated from B10.S female x (B10.S x SJL/J)F(1) male parents experienced significantly more EAE-related weight loss (P = 1.2 x 10(-4)) than females generated from F1 female x B10.S male parents. After controlling for this inheritance, a new locus at the centromeric end of chromosome 8 was identified that significantly influences both the development of paralysis (P = 8.2 x 10(-6)) and the incidence of CNS inflammation (P = 7.0 x 10(-5)) in EAE.

Serum tumour necrosis factor-alpha levels in cancer patients are discontinuous and correlate with weight loss

BACKGROUND

Tumour necrosis factor-alpha (TNF) has been regarded as a potential mediator of cancer cachexia. Assessment of TNF circulating levels in cancer patients and their correlation with weight loss has led to controversial results.

MATERIALS AND METHODS

We measured TNF circulating levels in 28 patients with gastrointestinal cancer and 29 controls with benign gastrointestinal diseases at different times (08.00 h, 14.00 h, 20.00 h) before operation.

RESULTS

TNF activity was not detected in any of controls at any times. In cancer patients, TNF circulating levels were detectable in 18 cases (64.3%) and appeared to be discontinuous. TNF levels above the limit of detection were present in 15 patients (53.6%) at 08.00 h, in 14 (50%) at 014.00 h and in nine (32.1%) at 20.00 h. Mean TNF levels were 14.3 +/- 4 pg mL(-1) at 08.00 h, 16.7 +/- 4.6 pg mL(-1) at 14.00 h (P = 0.05) and 18.5 +/- 10.2 pg mL(-1) at 20.00 h (P < 0.05 vs. 08.00 h and 14.00 h). According to Spearman's analysis, the sum of TNF concentrations at the three times significantly correlated with the severity of weight loss (Spearman's correlation coefficient = - 0.420; P = 0.026). TNF concentrations were consistently and significantly higher in patients with severe weight loss than in those with moderate or light weight loss at 08.00 h (26.3 +/- 8.3, 8.9 +/- 4.2, 3.8 +/- 2.1, respectively; P = 0.04 at one-way ANOVA). TNF levels were higher in anorectic than in nonanorectic patients at any hour, but the differences were not statistically significant.

CONCLUSIONS

The present study demonstrates that TNF is intermittently or discontinuously detectable in patients with gastrointestinal cancer and that its levels correlate with the severity of weight loss.

Pathophysiology of cancer cachexia

Cancer cachexia is a frequent complication observed in patients with malignant tumors. Although several decades have passed since the first focus on the metabolic dysfunction's associated with cancer, few effective therapeutic interventions have been successfully introduced into the medical armamentarium. The present study thoroughly reviews the basic pathophysiology of cancer cachexia and the treatment options already investigated in that field. Experimental and clinical studies were evaluated individually in order to clarify the intricate alterations observed in tumor-bearing patients. The difficulties in introducing sound and effective nutritional support or metabolic manipulation to reverse cancer cachexia are outlined in this review.

Provision of rhIGF-I/IGFBP-3 complex attenuated development of cancer cachexia in an experimental tumor model

Tumor growth is associated with development of cachexia which includes progressive wasting and anorexia. Our previous studies have indicated that insulin like growth factor-I (rhIGF-I) in complex with its binding protein 3 (IGFBP 3), but not free IGF-I, was a potent stimulator of muscle protein synthesis in rats with chronic undernutrition. The aim of the present study was to evaluate the effect of rhIGF-I/IGFBP-3 on the development of cancer cachexia, and to assess safety data on net tumor growth and progression during treatment.

METHODS

A methylcholantrene induced sarcoma was implanted s.c. in C 57 bl mice. The animals were provided with rhIGF-I/rhIGFBP-3 (5 microg/g bw) i.v. twice daily (n= 18). Controls were provided with saline (n= 20). Body weight and food intake were registered daily. Net tumor growth was measured over 10 days. Protein synthesis in liver and muscle, as well as plasma concentrations of glucose, insulin, IGF-I and amino acids were measured at the end of the study.

RESULTS

tumor size did not differ between control mice and rhIGF-I/rhIGFBP-3 treated mice (1.5 +/- 0.1 g wet tumor weight vs 1.6 +/- 0.2 g respectively). Saline treated tumor bearing controls lost 9.1 +/- 1.3 % body weight over 10 days due to rapid tumor growth while rhIGF-I/rhIGFBP-3 provision attenuated weight loss to 5.6 +/- 1.3% of body weight in study mice (P< 0.05). Food intake was improved and blood glucose concentration was reduced from 7.1 +/- 0.5 to 5.8 +/- 0.2 (P< 0.05) in response to treatment.

CONCLUSION

Our results demonstrate that rhIGF-I/rhIGFBP-3 complex did not affect net tumor growth. Moreover rhIGF-I/rhIGFBP-3 complex improved tumor-host nutritional state by improving food intake, attenuating weight loss and improving glucose metabolism.

Beta-adrenoceptor activity and resting energy metabolism in weight losing cancer patients

This study was aimed at comparing the blocking of beta-adrenoceptor activity to changes in the resting energy metabolism of 10 cancer patients with progressive weight loss due to solid malignant tumours. Resting energy expenditure (REE) as well as whole body carbohydrate and fat oxidation were investigated and related to plasma substrate levels (glucose, glycerol, free fatty acids (FFA)) before and after 5 days of oral administration of specific beta1 receptor blocker (atenolol, 50 mg/day) and non-specific beta1,beta2-adrenoceptor (propranolol, 80 mg/day) blockade. The administration order of the drugs was random, and a 3-day washout period was used in all individuals between the provision of the first and the second drug in order to minimise the risk of carry-over effects. Resting measurements in the morning after an overnight fast were performed by indirect calorimetry. Atenolol treatment reduced REE by 77+/-14 kcal/day and propranolol by 48+/-13 kcal/day, respectively (P<0.05 versus pretreatment values). Whole body oxygen uptake and carbon dioxide production were decreased similarly by both atenolol and propranolol treatment (P<0.05). Carbohydrate oxidation was increased by atenolol and decreased by propranolol, whilst fat oxidation was decreased by atenolol and unchanged by propranolol. The decrease in REE, accounting for the decline in heart rate, was significantly more pronounced following treatment with propranolol compared with atenolol (P<0.05). Atenolol and propranolol had no effect on blood glucose, plasma glycerol and FFA. We conclude that wastage in cancer patients is in part explained by increased beta(1) and beta(2)-adrenoceptor activity, in part secondary to elevated cardiovascular activity as a result of anaemia, loss of cardiac contractile capacity and altered host metabolism.

Inhibitors of prostaglandin synthesis do not improve food intake or body weight of tumor-bearing rats

Interleukin-1 (IL-1) and tumor necrosis factor (TNF) are immunoregulatory cytokines that mediate many aspects of the acute phase response to infection and injury. It has been hypothesized that these cytokines mediate the onset of the cachexia-anorexia syndrome with tumor growth. The anorexigenic effects of IL-1 are mediated in part by prostaglandins (PG). Therefore, the purpose of the present study was to determine if administration of ibuprofen (ibu) or indomethacin (indo), which inhibit PG synthesis, would affect the food intake and body weight of tumor-bearing rats. Rats were implanted with the Morris 7777 hepatoma, a tumor known to induce anorexia and weight loss in rats, and weight loss and leukocyte synthesis of IL-1 and TNF in mice. Treatment with indo or ibu did not improve food intake or body weight in the tumor-bearing rats. However, administration of ibu coincident with tumor implantation did result in smaller tumor mass compared to placebo-treated controls. The results of the present study suggest that PG synthesis is not a major factor in the onset of anorexia in this animal model of tumor-induced anorexia. However, further studies of the effects of inhibitors of PG synthesis on the kinetics of tumor growth are clearly indicated.

Use of recombinant human soluble TNF receptor in anorectic tumor-bearing rats

With progression of tumor growth, rats demonstrate anorexia and reduced food intake, a function of meal number and meal size. Tumor necrosis factor-alpha (TNF-alpha), a recognized anorectic agent, reacts with two different receptors (type I: 55 kDa; type II: 75 kDa). We used a dimeric, pegylated 55-kDa TNF receptor construct to test its effects on food intake, meal number, and meal size, which were continuously measured with a rat eater meter in 16 Fischer 344 male rats injected with 10(6) viable methylcholanthrene cells. When anorexia developed, rats received a subcutaneous injection of either 0.25 mg/kg body wt of soluble TNF receptor construct (study) or vehicle (tumor-bearing control). Before TNF inhibitor injection, no differences were observed in food intake, meal number, or meal size between the two groups. After the TNF inhibitor injection, study vs. control rats significantly improved food intake as a result of an increase in meal number and meal size. Rats also showed a significant improvement in body weight. These data suggest that TNF-alpha, in addition to other cytokines, contributes to the anorexia of tumor growth, probably mediated via the hypothalamus.

Geriatric cachexia: the role of cytokines

Weight loss in elderly patients is a common clinical problem. Wasting and cachexia are associated with severe physiologic, psychologic, and immunologic consequences, regardless of the underlying causes. Cachexia has been associated with infections, decubitus ulcers, and even death. Multivariate analyses of risk and prognostic factors in community-acquired pneumonia in the elderly have found that age by itself is not a significant factor related to prognosis. Among the significant risk factors, only nutritional status is amenable to medical intervention. Cachexia in the elderly may have profound consequences: medical, cognitive, and psychiatric disorders may diminish self-reliance in activities of daily living, thus reducing quality of life and increasing the frequency of secondary procedures, hospitalizations, and the need for skilled care. Cachexia is associated with higher-than-normal concentrations of tumor necrosis factor alpha (TNF-alpha), interleukin (IL) 1, IL-6, serotonin, and interferon gamma. The role of these proinflammatory cytokines has been established in the cachexia seen in cancer and AIDS patients. Reduction in the concentrations of these cytokines is associated with weight gain. Drugs that promote appetite stimulation and weight gain, such as progestational agents, cyproheptadines, pentoxifylline, and thalidomide may work by down-regulating these proinflammatory cytokines. An understanding of the relation between cachexia and negative regulatory cytokines may point to effective treatment of geriatric cachexia as well.

Cachexia in experimental models

Cachexia refers to a state of severe malnutrition characterized by anorexia, weight loss, and muscle wasting. Although it is most commonly considered in the context of cancer, it may occur as a consequence of a variety of chronic diseases. Cachexia appears to differ from "semistarvation" in that there is evidence of metabolic changes that are different from the normal response to reduce food intake. Animal models are useful in the study of cachexia because they allow homogeneous groups of subjects, free from confounding influences, to be studied. Accurate control of diet is possible, and pair-fed controls can be used to allow specific investigation of the metabolic component. However, the model must show features that are appropriate for the disease being studied. In the case of cancer this means using a model in which cachexia occurs without too high a tumor burden or growth rate or too severe a reduction in food intake. Studies in the author's laboratory have used a transplantable Leydig cell tumor in Fischer rats. Food intake decreases by 20-40% and energy expenditure is greater than that of pair-fed controls. One mechanism that may be responsible for this relates to the postprandial metabolism of carbohydrate, since after a test meal there appears to be a greater rate of hepatic glycogen synthesis via the indirect pathway in tumor-bearing rats than in controls. The indirect pathway involves gluconeogenic enzymes, and studies using a variety of different tracers and enzyme inhibitors suggest that amino acids are important precursors. An increased rate of hepatic glycogen synthesis also appears to be maintained for a longer time after the meal in tumor-bearing rats, and this may act to delay the onset of the next meal, thereby explaining the decreased meal frequency that has been observed.

Altered release of tumor necrosis factor and its soluble receptor in non-Hodgkin's lymphoma patients

Increased expression and elevated serum levels of tumor necrosis factor-alpha (TNF-alpha) have been shown to be associated with the presence of constitutional B symptoms and poor prognosis in non-Hodgkin's lymphoma (NHL) patients. Soluble TNF receptors (sTNF-R) are suggested to act as biological buffers in inflammatory conditions by binding and inactivating increased circulating TNF. Whereas studies have shown elevated TNF to be correlated with B symptoms, similar studies showing the status of soluble receptor release in these patients have not been conducted. Here, we show that there is increased soluble p75 TNF receptor release from peripheral blood mononuclear cells (PBMNC) in NHL patients in the early stages of the disease but it is severely depressed in patients with advanced disease. Decreased release is associated with presence of B symptoms in these patients. All NHL patients also show increased TNF secretion and a decreased rate of receptor release with time compared with healthy controls. These findings imply that decreased sTNF-R receptor release, in addition to increased TNF secretion, is also important in predisposing the patients to B symptoms. This opens up the possibility of the use of sTNF-Rs as a therapeutic tool to counter increased TNF and alleviate systemic symptoms in these patients and also as a marker for the progression of the 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.

Tumour inoculation site-dependent induction of cachexia in mice bearing colon 26 carcinoma

Murine colon 26 carcinoma growing at either subcutaneous (s.c.) or intramuscular (i.m.) inoculation sites causes cachexia in mice. Such animals show extensive loss of body weight, wasting of the muscle and adipose tissues, hypoglycaemia, and hypercalcaemia, even when the tumour weight comprises only about 1.9% of carcass weight. In contrast, the same tumour when inoculated into the liver does not cause any sign of tumour-related cachexia even when the tumour becomes much larger (6.6% of carcass weight). Interleukin 6 (IL-6), a mediator associated with cachexia in this tumour model, is detected at high levels both in the tumour tissues and in the circulating blood of mice bearing colon 26 tumour at the s.c. inoculation site. In contrast, only minute levels of IL-6 are detected in the tumour grown in the liver. The colon 26 tumour grown in the liver does not lose its ability to cause cachexia, because the tumour when re-inoculated s.c. is able to cause extensive weight loss and produce IL-6 as did the original colon 26 cell line. Histological studies revealed differences in the composition of tumour tissues: the tumours grown in the subcutis consist of many polygonal tumour cells, extended-intercellular space, and high vascular density, whereas those grown in the liver consist of spindle-shaped tumour cells. Thus, the environment where tumour cells grow would be a critical factor in determining the cachectic phenotype of cancer cells, including their ability to produce IL-6.

Isolation, characterization, and distribution of a 24-kDa proteoglycan in the urine of cachectic cancer and AIDS patients

Substantial weight loss in individuals with AIDS or cancer is associated with a poor prognosis and increased mortality. We have isolated and partially characterized a proteoglycan (named azaftig) from the urine of a cancer patient experiencing weight loss. Furthermore, we have raised a polyclonal antibody to azaftig in rabbits and developed a procedure to measure the level of this proteoglycan in urine by Western blot. We report the presence of azaftig in the urine of cancer and AIDS patients experiencing weight loss, but not in the control or weight-stable subjects. The azaftig-like immunoreactivity was present in 69.2% (9/13) of patients with weight loss, but only in 27.0% (3/11) of weight-stable cancer or AIDS patients and none of the control subjects (n = 8).

Increased serum concentrations of soluble tumor necrosis factor receptor I in noncachectic and cachectic patients with advanced gastric and colorectal cancer

The serum levels of soluble tumor necrosis factor receptor I (sTNF-RI) were measured in 74 noncachectic patients including 42 with gastric cancer and 32 with colorectal cancer, as well as in 39 patients with severe cachexia and 15 healthy volunteers. The sTNF-RI levels increased with the advance of disease, being highest in the cachectic patients. The levels were inversely correlated with the serum concentrations of nutritional parameters such as prealbumin, transferrin, retinol binding protein, and the percentages of CD3(+) cells in the peripheral blood lymphocytes, and positively correlated with the serum concentration of immunosuppressive acidic protein (IAP) and soluble interleukin-2 receptors. These findings suggest that sTNF-RI could be an important prognostic factor to predict the advance of gastric and colorectal cancers and deterioration of the patient's nutritional and immune activity.

Serotonin-immune interactions in elderly volunteers and in patients with Alzheimer's disease (DAT): lower plasma tryptophan availability to the brain in the elderly and increased serum interleukin-6 in DAT

The aims of this study were to examine the plasma availability of tryptophan, the precursor of 5-hydroxytryptamine (5-HT), and serum cytokines, such as interleukin-6 (IL-6) and IL-8, in normal elderly volunteers and in patients with Alzheimer's disease (DAT). Elderly normal volunteers (mean age = 78.3 +/- 5.7 years) had a significantly lower tryptophan/competing amino acids (valine + leucine + isoleucine + phenylalanine + tyrosine) ratio than younger subjects (mean age = 32.9 +/- 8.1 years). In normal volunteers, there were significant and inverse relationships between age and either plasma tryptophan or the tryptophan/competing amino acids ratio, and between the availability of tryptophan to the brain and serum IL-6 or IL-8. DAT patients had significantly higher serum IL-6, but not IL-8, than age-matched normal volunteers. There were no significant differences in the availability of tryptophan to the brain between DAT patients and age-matched normal volunteers. The results suggest that: 1) in normal humans, the availability of plasma tryptophan to the brain decreases with age, and with activation of the immune system; and 2) increased production of IL-6 may play a role in the pathogenesis of DAT.

Serotonin-immune interactions in detoxified chronic alcoholic patients without apparent liver disease: activation of the inflammatory response system and lower plasma total tryptophan

The aims of the present study were to examine (1) the inflammatory response system (IRS), through measurements of serum interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), sgp130 (the soluble form of the IL-6 transducer signal protein), CC16 (Clara Cell protein; an endogenous anti-cytokine), IL-1R antagonist (IL-1RA), IL-8 and sCD14; and (2) the availability of plasma total tryptophan to the brain in chronic alcoholic patients without apparent liver disease (AWLD). Detoxified AWLD patients had significantly lower plasma tryptophan and serum CC16 and significantly higher serum IL-1RA and IL-8 concentrations than normal volunteers. There were significant correlations between the availability of tryptophan to the brain and serum IL-6, IL-8 and IL-1RA (all negative) and CC16 (positive). The results suggest that (1) there is, in detoxified AWLD patients, an activation of the monocytic arm of cell-mediated immunity and a lowered anti-inflammatory capacity of the serum; and that (2) lower availability of plasma tryptophan to the brain in detoxified AWLD patients is related to activation of the IRS. Lower CC16 may be one factor predisposing chronic alcoholic patients toward infectious disorders.

Nutritional support of the pediatric oncology patient

The child with a malignancy frequently will have associated cachexia with significant weight loss and malnutrition. The reasons for this are multifactorial and may be related directly to the tumor, such as increased metabolic rate, circulating peptides leading to anorexia, and decreased intake due to poor appetite or gut involvement. There appears to be other reasons involved, including increased whole body protein breakdown, increased lipolysis, and increased gluconeogenesis. Release of certain cytokines, such as tumor necrosis factor, interleukin-1, interleukin-6, and others may increase the cancer cachexia. Malnutrition in these children leads to intolerance of chemotherapy and radiotherapy as well as increased local and systemic infections. For many years, oncologists were hesitant to provide nutrition support to cancer patients for fear that tumor growth would be enhanced. Pediatric oncologists learned early that starvation plays no positive role in cancer therapy. Adjunctive nutritional support, either enterally or parenterally, supports the patient during therapy with surgery, chemotherapy, or radiation. Many studies have now shown that the nutritionally replete patient tolerates therapy better and in some pediatric malignancies may enhance survival.

Suppression of carcass weight loss in cachexia in rats bearing Leydig cell tumor by the novel compound NO-1886, a lipoprotein lipase activator

The Leydig cell tumor has been reported to produce tumor necrosis factor (TNF) and induce cachexia in rats. TNF is thought to reduce lipoprotein lipase (LPL) activity, decrease fat deposits, induce emaciation, and worsen cachexia. Therefore, we thought emaciation might be prevented and thus cachexia improved by increasing LPL activity. We administered NO-1886, a lipoprotein lipase activator, to rats bearing Leydig cell tumor and observed its effect on improving the cachexia induced by the tumor. In Leydig cell tumor-bearing rats, the emaciation progressed after tumor inoculation and the general condition worsened daily. Plasma levels of total protein, albumin, and glucose, which are biological parameters of malnutrition, were found to decrease soon after tumor inoculation in tumor-bearing rats. In contrast, rats given NO-1886 showed less malnutrition than tumor-bearing rats. LPL activity of rat adipose tissue was decreased, the weight of adipose tissue was decreased, carcass weight was reduced, and food consumption was decreased after Leydig cell tumor inoculation. NO-1886 increased adipose tissue LPL activity and suppressed the decrease in the weight of adipose tissue, carcass weight, and food consumption due to cachexia without influencing tumor growth. The present results suggest that the novel compound NO-1886 may suppress carcass weight loss in rats bearing Leydig cell tumor by suppressing the decrease in food consumption and LPL activity.

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.

Effects of lentinan on abnormal ingestive behaviors induced by tumor necrosis factor

Lentinan (LNT), a beta-glucan derived from Lentinus edodes (Berk.) Sign., is known to work positively against cachexia in patients with malignant tumors. Because the cachectin/tumor necrosis factor (TNF) is supposed to be one of the factors that mediate cancer cachexia, we tested the effects of LNT on TNF-induced cachexia in rats. First, we analyzed in detail the cachectic actions of TNF (0.2 mg/kg/day, 5 days, IV) on food and water intake, body weight, and locomotor activity. The day after the first administration of TNF (acute phase), food and water intake, as well as body weight, of all rats decreased. However, over the next few days of treatment (chronic phase), the rats gradually developed a tolerance to the cachectic actions of TNF. Specifically, after the third administration, the rats treated with TNF had a higher amount of water intake than the control rats. This was mainly due to an increase in daytime water intake. We also analyzed the effects of LNT (0.1 or 1.0 mg/kg, twice/wk. IV) on TNF-induced cachexia, and compared the data with those from the rats treated with TNF alone. The higher dosage of LNT significantly suppressed TNF-induced daytime polydipsia and increased the amount of nighttime water intake, as well as the meal size of nighttime food intake. These results suggest that LNT partially normalizes TNF-induced cachexia in rats.

Multiple cytokines and acute inflammation raise mouse leptin levels: potential role in inflammatory anorexia

Several inflammatory cytokines, most notably tumor necrosis factor (TNF) and IL-1, induce anorexia and loss of lean body mass, common manifestations of acute and chronic inflammatory conditions. In C57BL/6 female mice, the administration of TNF, IL-1, and, to a lesser extent, leukemia inhibitory factor (LIF), produced a prompt and dose-dependent increase in serum leptin levels and leptin mRNA expression in fat. IL-10, IL-4, ciliary neurotrophic factor, and IL-2, cytokines not known to induce anorexia or decrease food intake, had no effect on leptin gene expression or serum leptin levels. After administration of Escherichia coli lipopolysaccharide (LPS), leptin gene expression and leptin levels were increased. These findings suggest that leptin levels may be one mechanism by which anorexia is induced during acute inflammatory conditions.

Molecular cloning of a gene encoding a new type of metalloproteinase-disintegrin family protein with thrombospondin motifs as an inflammation associated gene

A cellular disintegrin and metalloproteinase (ADAM) is a new family of genes with structural homology to the snake venom metalloproteinases and disintegrins. We screened genes which were selectively expressed in the cachexigenic colon 26 adenocarcinoma subline in vivo. It was found that one novel cDNA clone, identified as a cachexigenic tumor selective gene, encodes a cysteine-rich protein which shows a sequence similarity to that of both the snake venom metalloproteinases and thrombospondins. We named this cDNA clone A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS-1). ADAMTS1 consists of six domains, 1) a pro- and 2) a metalloproteinase, 3) a disintegrin-like, 4) a thrombospondin (TSP) homologous domain containing TSP type I motif, 5) a spacer region, and 6) COOH-terminal TSP submotifs. Unlike other ADAMs, ADAMTS-1 does not possess a transmembrane domain and is a putative secretory protein. Therefore, ADAMTS-1 is a new type of ADAM family protein with TSP type I motifs. We demonstrated that the TSP homologous domain containing the TSP type I motif of ADAMTS-1 is functional for binding to heparin. ADAMTS-1 mRNA could be induced by stimulating colon 26 cells with an inflammatory cytokine, interleukin-1, in vitro. Moreover, intravenous administration of lipopolysaccharide in mice selectively induced ADAMTS-1 mRNA in kidney and heart. These data suggest that ADAM-TS-1 may be a gene whose expression is associated with various inflammatory processes as well as development of cancer cachexia.

Serotonin-immune interactions in major depression: lower serum tryptophan as a marker of an immune-inflammatory response

Serum total tryptophan and the five competing amino acids (CAA), i.e., valine, leucine, tyrosine, phenylalanine, and isoleucine were determined in 35 major depressed subjects of whom 27 with treatment resistant depression (TRD), and 15 normal controls. Twenty-five of the depressed subjects had repeated measurements of the amino acids both before and after antidepressive treatment. The following immune-inflammatory variables were assayed in the above subjects: serum zinc (Zn), total serum protein (TSP), albumin (Alb), transferrin (Tf), iron (Fe), high-density lipoprotein cholesterol (HDL-C), number of peripheral blood leukocytes, and the CD4+/CD8+ T cell (T-helper/T-suppressor) ratio. Serum tryptophan and the tryptophan/CAA ratio were significantly lower in major depressed subjects than in normal controls. The tryptophan/CAA ratio was significantly lower in patients with TRD than in patients without TRD and normal controls. There were no significant alterations in any of the amino acids upon successful therapy. There were significant correlations between serum tryptophan and serum Zn, TSP, Alb, Tf, Fe, and HDL-C (all positive), and number of leukocytes and the CD4+/CD8+ T-cell ratio (all negative). The tryptophan/CAA ratio was significantly and negatively related to the number of leukocytes and the CD4+/CD8+ T-cell ratio. The results suggest that (a) TRD is characterized by lower availability of serum tryptophan; (b) the availability of tryptophan may remain decreased despite clinical recovery; and (c) the lower availability of tryptophan is probably a marker of the immune-inflammatory response during major depression.

Nutrition and HIV infection in children

HIV infection has profound effects on a patient's nutritional status because it can modulate appetite, nutrient absorption and basal metabolic rate. In addition, HIV infection can lead to the depletion of a variety of vitamins and micronutrients including vitamins A, D, B2, B6, B12, L-carnitine, iron, zinc and selenium. This review article summarizes existing data regarding nutritional defects in HIV-infected patients and the results of clinical studies addressing the effects of nutritional supplementation in infected patients.

Early detection of cancer cachexia in the rat using 31P magnetic resonance spectroscopy of the liver and a fructose stress test

The dynamic metabolic effects of a fructose infusion challenge on hepatic intracellular levels of adenosine 5'-triphosphate (ATP), inorganic phosphate (Pi) and phosphomonoesters (PME) were monitored noninvasively by 31P MRS in a remote tumour-bearing rat model. Fisher male rats were inoculated with a methylcholanthrene-induced sarcoma. Seventeen rats were randomized into three groups: control (n = 6), low tumour burden (LTB, n = 6), or moderate tumour burden (MTB, n = 5). The LTB group had tumour burdens of 0.2-2.0% while the MTB group had tumour burdens of 2.6-5.7%. All rats were in the pre-clinical phase of cancer cachexia as determined by food intake and body weight. Rats were infused with 1.2 g/kg of fructose i.v. and the metabolic response of the liver was monitored with time over 1 h via 31P MRS. In all groups an immediate increase in hepatic levels of PME was noted, which returned to baseline values over the course of the experiment, reflecting the phosphorylation of fructose to fructose 1-phosphate. For the MTB rats, the return to baseline levels was more rapid than in the control or LTB group. All groups experienced a 20% decrease in hepatic ATP levels which did not return to baseline over the 1 h observation period. As well, all groups experienced an initial fall in Pi, which recovered to prefructose levels or greater. MTB rats demonstrated a 30-40% increase in Pi concentration and a 60-70% increase in Pi/ATP ratio after infusion with fructose as compared to LTB and control rats (ANOVA;p<0.05). This is consistent with cachexia-induced enhancement of hepatic gluconeogenic activity, and hence more rapid release of Pi from the phosphorylated metabolites in the MTB rats. Thus fructose infusion and hepatic 31P MRS permit pre-clinical detection of cancer cachexia as reflected by increased Pi generation and more rapid removal of PME.

Are cytokines possible mediators of cancer cachexia?

The possible role of cytokines in the development of cancer cachexia was reviewed from the literature. Tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, IL-6, interferon (IFN)-gamma and leukemia inhibitory factor (LIF) can elicit many but not all host changes seen in cancer cachexia, including loss of appetite, loss of body weight, and the induction of acute-phase protein synthesis. However, these cytokines are not always demonstrated in the circulation of the cancer patients. The inability to detect circulating cytokines may be due to their low rate of production, their short half-life and rapid clearance from plasma, or their mode of action (autocrine or paracrine). Different cytokines are induced to stimulate the same response. This is very different from hormonal regulation, where a hormone acts on a cell directly through a specific receptor without depending on other mediators. Specific antibodies including anti-IFN-gamma, anti-TNF and anti-IL-6 antibodies, as well as the cyclooxygenase inhibitor indomethacin, have been used to reverse cancer cachexia. Overlapping physiologic activities make it unlikely that a single substance is the sole cause of cancer cachexia. It is hoped that further investigation on other cytokines and their possible relationships with hormones will help to clarify the mechanisms of cancer cachexia in the near future.

Establishment and characterization of cachexia-inducing and -non-inducing clones of murine colon 26 carcinoma

To investigate the mechanism causing cachexia and its association with shorter patient survival, we cloned weight-loss-inducing and -non-inducing sublines of murine colon 26 carcinoma (colon 26). One clone, clone 20, induced substantial weight loss, wasting of adipose tissue and muscle, and hypoglycemia in mice with a minimum tumor burden of 0.3 g (2 g per 100 g body weight). Clone-20-bearing mice had a median survival of 24.5 days with average tumor weight of 0.4 g. In contrast, clone 5 induced neither severe weight loss, wasting of adipose tissue and muscle, nor hypoglycemia; clone-5-bearing mice survived for a median of 70 days with average tumor weight of 12 g. These results clearly indicate that shorter survival is associated with the degree of cachexia and is independent of tumor size. Using this pair of colon 26 clones, we examined mediators of cachexia. Neither TNF alpha, IL-1 alpha nor IFN gamma was detected in the serum of mice bearing either clone, while IL-6 was detected in mice bearing both clones by ELISA and a bioassay. Administration of anti-IL-6 monoclonal antibody (MAb) partially but significantly suppressed cachexia induction in clone-20-bearing mice. These results point to the involvement of IL-6 in experimental cachexia. However, our finding of the presence of IL-6 in the serum of mice bearing clone 5, which does not induce weight loss, clearly indicates that IL-6 is not solely responsible for the induction of cachexia.

Cytokine-mediated alterations in host metabolism prevent nutritional repletion in cachectic cancer patients

The clinical syndrome of cachexia is characterized by anorexia, continued losses of lean body mass, and altered carbohydrate and lipid metabolism. As early as the 1930s, this "chronic wasting" syndrome had been identified as the most frequent immediate cause of death in patients with cancer [Warren: Am J Med Sci 184:610-619, 1932]. At present, controversy remains as to the benefit of supplemental parenteral or enteral feedings in the nutritional repletion of cachectic cancer patients, since only selected patient groups have demonstrated clear benefit from their administration [Copeland et al.: Cancer 43:2108-2116, 1979; Copeland et al.: Cancer Res 37:2451-2456, 1977; Terepka and Waterhouse: Am J Med 20:225-238, 1956]. Despite having these advanced nutritional modalities firmly in our therapeutic armamentarium, the progression of cachexia in the nutritionally depleted cancer patient often continues unabated, and our ability to intervene successfully remains limited. This review proposes that host: tumor interactions lead to a nonspecific inflammatory response mediated in part by the chronic production and release of proinflammatory cytokines, including interleukin-1, tumor necrosis factor alpha, interleukin-6 and interferon-gamma, which antagonize the anabolic signals associated with enteral and parenteral nutrition support. Cytokine-mediated alterations can explain the inability of adequate dietary nitrogen and calories to result in lean tissue repletion. Based on this proposal, interrupting proinflammatory cytokine production or target organ action may be an appropriate therapeutic objective to improve nutrient utilization in patients with tumors.

Cachexia-anorexia-asthenia

The National Cancer Institute (Canada) sponsored a workshop on symptom control in Banff, Alberta, in October 1993. This article reports on the workshop recommendations for research on one symptom complex, the cachexia-anorexia-asthenia syndrome. In addition to encouraging study generation, the recommendations provide a baseline for assessing the scope and strength of future Canadian research initiatives on cachexia-anorexia-asthenia.