Exploiting common aspects of obesity and cancer cachexia for future therapeutic strategies

Obesity and cancer cachexia are diseases at opposite ends of the BMI. However, despite the apparent dichotomy, these pathologies share some common underlying mechanisms that lead to profound metabolic perturbations. Insulin resistance, adipose tissue lipolysis, skeletal muscle atrophy and systemic inflammation are key players in both diseases. Several strategies for pharmacological treatments have been employed in obesity and cancer cachexia but demonstrated only limited effects. Therefore, there is still a need to develop novel, more effective strategies. In this review we summarize existing therapies and discuss potential novel strategies that could arise by bridging common aspects between obesity and cachexia. We discuss the potential role of macrophage manipulation and the modulation of inflammation by targeting Nuclear Receptors (NRs) as potential novel therapeutic strategies.

Microglia in the hypothalamus respond to tumor-derived factors and are protective against cachexia during pancreatic cancer

Microglia in the mediobasal hypothalamus (MBH) respond to inflammatory stimuli and metabolic perturbations to mediate body composition. This concept is well studied in the context of high fat diet induced obesity (HFDO), yet has not been investigated in the context of cachexia, a devastating metabolic syndrome characterized by anorexia, fatigue, and muscle catabolism. We show that microglia accumulate specifically in the MBH early in pancreatic ductal adenocarcinoma (PDAC)-associated cachexia and assume an activated morphology. Furthermore, we observe astrogliosis in the MBH and hippocampus concurrent with cachexia initiation. We next show that circulating immune cells resembling macrophages infiltrate the MBH. PDAC-derived factors induced microglia to express a transcriptional profile in vitro that was distinct from that induced by lipopolysaccharide (LPS). Microglia depletion through CSF1-R antagonism resulted in accelerated cachexia onset and increased anorexia, fatigue, and muscle catabolism during PDAC. This corresponded with increased hypothalamic-pituitary-adrenal (HPA) axis activation. CSF1-R antagonism had little effect on inflammatory response in the circulation, liver, or tumor. These findings demonstrate that microglia are protective against PDAC cachexia and provide mechanistic insight into this function.

IL-1R Regulates Disease Tolerance and Cachexia in Toxoplasma gondii Infection

Toxoplasma gondii is an obligate intracellular parasite that establishes life-long infection in a wide range of hosts, including humans and rodents. To establish a chronic infection, pathogens often exploit the trade-off between resistance mechanisms, which promote inflammation and kill microbes, and tolerance mechanisms, which mitigate inflammatory stress. Signaling through the type I IL-1R has recently been shown to control disease tolerance pathways in endotoxemia and Salmonella infection. However, the role of the IL-1 axis in T. gondii infection is unclear. In this study we show that IL-1R-/- mice can control T. gondii burden throughout infection. Compared with wild-type mice, IL-1R-/- mice have more severe liver and adipose tissue pathology during acute infection, consistent with a role in acute disease tolerance. Surprisingly, IL-1R-/- mice had better long-term survival than wild-type mice during chronic infection. This was due to the ability of IL-1R-/- mice to recover from cachexia, an immune-metabolic disease of muscle wasting that impairs fitness of wild-type mice. Together, our data indicate a role for IL-1R as a regulator of host homeostasis and point to cachexia as a cost of long-term reliance on IL-1-mediated tolerance mechanisms.

Consumption of latex from Euphorbia tirucalli L. promotes a reduction of tumor growth and cachexia, and immunomodulation in Walker 256 tumor-bearing rats

ETHNOPHARMACOLOGICAL RELEVANCE

Euphorbia tirucalli L. is an African plant that grows well in Brazil. Individuals diagnosed with cancer frequently consume latex from E. tirucalli, dissolved in drinking water. In vitro studies confirm the antitumor potential of E. tirucalli latex, but in vivo evaluations are scarce.

AIM OF THE STUDY

To evaluate the effect of intake of an aqueous solution of E. tirucalli latex on tumor growth, cachexia, and immune response in Walker 256 tumor-bearing rats.

MATERIALS AND METHODS

Latex from E. tirucalli was collected and analyzed by LC-MS. Sixty male Wistar rats (age, 90 days) were randomly divided into four groups: C, control group (without tumor); W, Walker 256 tumor-bearing group; SW1, W animals but treated with 25 μL latex/mL water; and SW2, W animals but treated with 50 μL latex/mL water. Animals received 1 mL of latex solution once a day by gavage. After 15 d, animals were euthanized, tumor mass was determined, and glucose and triacylglycerol serum levels were measured by using commercial kits. Change in the body weight during tumor development was calculated, and proliferation capacity of tumor cells was assessed by the Alamar Blue assay. Phagocytosis and superoxide anion production by peritoneal macrophages and circulating neutrophils were analyzed by enzymatic and colorimetric assays. Data are analyzed by one-way ANOVA followed by Tukey's post-hoc test, with the significance level set at 5%.

RESULTS

The analysis of the latex revealed the presence of triterpenes. The ingestion of the latex aqueous solution promoted 40% and 60% reduction of the tumor mass in SW1 and SW2 groups, respectively (p < 0.05). The proliferative capacity of tumor cells from SW2 group was 76% lower than that of cells from W group (p < 0.0001). Animals treated with latex gained, on average, 20 g (SW1) and 8 g (SW2) weight. Glucose and triacylglycerol serum levels in SW1 and SW2 animals were similar to those in C group rats. Peritoneal macrophages and blood neutrophils from SW1 and SW2 animals produced 30-40% less superoxide anions than those from W group animals (p < 0.05), but neutrophils from SW2 group showed an increased phagocytic capacity (20%, vs. W group).

CONCLUSIONS

E. tirucalli latex, administered orally for 15 d, efficiently reduced tumor growth and cachexia in Walker 256 tumor-bearing rats. Decreased tumor cell proliferative capacity was one of the mechanisms involved in this effect. Further, the data suggest immunomodulatory properties of E. tirucalli latex. The results agree with folk data on the antitumor effect of latex ingestion, indicating that it may be useful as an adjunct in the treatment of cancer patients. For this, further in vivo studies in animal and human models need to be conducted.

Systemic inflammation in colorectal cancer: Underlying factors, effects, and prognostic significance

Systemic inflammation is a marker of poor prognosis preoperatively present in around 20%-40% of colorectal cancer patients. The hallmarks of systemic inflammation include an increased production of proinflammatory cytokines and acute phase proteins that enter the circulation. While the low-level systemic inflammation is often clinically silent, its consequences are many and may ultimately lead to chronic cancer-associated wasting, cachexia. In this review, we discuss the pathogenesis of cancer-related systemic inflammation, explore the role of systemic inflammation in promoting cancer growth, escaping antitumor defense, and shifting metabolic pathways, and how these changes are related to less favorable outcome.

Doxorubicin triggers splenic contraction and irreversible dysregulation of COX and LOX that alters the inflammation-resolution program in the myocardium

Doxorubicin (DOX) is a widely used drug for cancer treatment as a chemotherapeutic agent. However, the cellular and integrative mechanism of DOX-induced immunometabolism is unclear. Two-month-old male C57BL/6J mice were divided into high- and low-dose DOX-treated groups with a maintained saline control group. The first group was injected with a high dose of DOX (H-DOX; 15 mg·kg-1·wk-1), and the second group was injected with 7.5 mg·kg-1·wk-1 as a latent low dose of DOX (LL-DOX). H-DOX treatment led to complete mortality in 2 wk and 70% survival in the LL-DOX group compared with the saline control group. Therefore, an additional group of mice was injected with an acute high dose of DOX (AH-DOX) and euthanized at 24 h to compare with LL-DOX and saline control groups. The LL-DOX and AH-DOX groups showed obvious apoptosis and dysfunctional and structural changes in cardiac tissue. Splenic contraction was evident in AH-DOX- and LL-DOX-treated mice, indicating the systems-wide impact of DOX on integrative organs of the spleen, which is essential for cardiac homeostasis and repair. DOX dysregulated splenic-enriched immune-sensitive lipoxygenase and cyclooxygenase in the spleen and left ventricle compared with the saline control group. As a result, lipoxygenase-dependent D- and E-series resolvin precursors, such as 16HDoHE, 4HDoHE, and 12-HEPE, as well as cyclooxygenase-mediated PG species (PGD2, PGE2, and 6-keto-PG2α) were decreased in the left ventricle, suggestive of defective immunometabolism. Both AH-DOX and LL-DOX induced splenic contraction and expansion of red pulp with decreased CD169+ metallophilic macrophages. AH-DOX intoxicated macrophages in the spleen by depleting CD169+ cells in the acute setting and sustained the splenic macrophage loss in the chronic phase in the LL-DOX group. Thus, DOX triggers a vicious cycle of splenocardiac cachexia to facilitate defective immunometabolism and irreversible macrophage toxicity and thereby impaired the inflammation-resolution program. NEW & NOTEWORTHY Doxorubicin (DOX) triggered splenic mass loss and decreased CD169 with germinal center contraction in acute and chronic exposure. Cardiac toxicity of DOX is marked with dysregulation of immunometabolism and thereby impaired resolution of inflammation. DOX suppressed physiological levels of cytokines and chemokines with signs of splenocardiac cachexia.

Toxoplasma gondii infection triggers chronic cachexia and sustained commensal dysbiosis in mice

Toxoplasma gondii is a protozoan parasite with a predation-mediated transmission cycle between rodents and felines. Intermediate hosts acquire Toxoplasma by eating parasite cysts which invade the small intestine, disseminate systemically and finally establish host life-long chronic infection in brain and muscles. Here we show that Toxoplasma infection can trigger a severe form of sustained cachexia: a disease of progressive lean weight loss that is a causal predictor of mortality in cancer, chronic disease and many infections. Toxoplasma cachexia is characterized by acute anorexia, systemic inflammation and loss of 20% body mass. Although mice recover from symptoms of peak sickness, they fail to regain muscle mass or visceral adipose depots. We asked whether the damage to the intestinal microenvironment observed at acute time points was sustained in chronic infection and could thereby play a role in sustaining cachexia. We found that parasites replicate in the same region of the distal jejunum/proximal ileum throughout acute infection, inducing the development of secondary lymphoid structures and severe, regional inflammation. Small intestine pathology was resolved by 5 weeks post-infection. However, changes in the commensal populations, notably an outgrowth of Clostridia spp., were sustained in chronic infection. Importantly, uninfected animals co-housed with infected mice display similar changes in commensal microflora but never display symptoms of cachexia, indicating that altered commensals are not sufficient to explain the cachexia phenotype alone. These studies indicate that Toxoplasma infection is a novel and robust model to study the immune-metabolic interactions that contribute to chronic cachexia development, pathology and potential reversal.

Metabolic Inflammatory Complex in Sepsis: Septic Cachexia as a Novel Potential Therapeutic Target

Despite several decades of focused investigation, sepsis remains a major cause of mortality in critically ill patients. Advancements in intensive care have enabled more patients to survive the acute phase of sepsis than previously, but a growing number of them progress to chronic critical illness. The failure of previous randomized clinical trials of anti-inflammatory agents to show any pro-survival benefit in septic patients underscores current thought that simple anti-inflammatory strategies are ineffective because the inhibitory effect of anti-inflammatory agents undermines the immune response to pathogens. New strategies with the dual capability of ameliorating inflammation in organs while stimulating antimicrobial activity are eagerly awaited. On the other hand, the metabolic alterations associated with systemic inflammatory response, including mitochondrial dysfunction and metabolic shift, are closely linked through a nexus of signaling pathways and signaling molecules. Preventing these metabolic derangements may be an alternative way to control excessive inflammation, an intriguing possibility that has not been fully explored. New insight into the molecular pathogenesis of sepsis and sepsis-associated chronic critical illness has led to the recognition of septic cachexia, a life-threatening form of metabolic inflammatory complex associated with multiple organ dysfunction. The potential for septic cachexia to serve as a novel target disease state to improve the clinical outcome of septic patients is discussed in this review.

The role of hypothalamic inflammation, the hypothalamic-pituitary-adrenal axis and serotonin in the cancer anorexia-cachexia syndrome

PURPOSE OF REVIEW

In cancer patients, the development of cachexia (muscle wasting) is frequently aggravated by anorexia (loss of appetite). Their concurrence is often referred to as anorexia-cachexia syndrome. This review focusses on the recent evidence underlining hypothalamic inflammation as key driver of these processes. Special attention is given to the involvement of hypothalamic serotonin.

RECENT FINDINGS

The anorexia-cachexia syndrome is directly associated with higher mortality in cancer patients. Recent reports confirm its severe impact on the quality of life of patients and their families.Hypothalamic inflammation has been shown to contribute to muscle and adipose tissue loss in cancer via central hypothalamic interleukine (IL)1β-induced activation of the hypothalamic-pituitary-adrenal axis. The resulting release of glucocorticoids directly stimulates catabolic processes in these tissues via activation of the ubiquitin-proteosome pathway. Next to this, hypothalamic inflammation has been shown to reduce food intake in cancer by triggering changes in orexigenic and anorexigenic responses via upregulation of serotonin availability and stimulation of its signalling pathways in hypothalamic tissues. This combination of reduced food intake and stimulation of tissue catabolism represents a dual mechanism by which hypothalamic inflammation contributes to the development and maintenance of anorexia and cachexia in cancer.

SUMMARY

Hypothalamic inflammation is a driving force in the development of the anorexia-cachexia syndrome via hypothalamic-pituitary-adrenal axis and serotonin pathway activation.

ICF-specific DNMT3B dysfunction interferes with intragenic regulation of mRNA transcription and alternative splicing

Hypomorphic mutations in DNA-methyltransferase DNMT3B cause majority of the rare disorder Immunodeficiency, Centromere instability and Facial anomalies syndrome cases (ICF1). By unspecified mechanisms, mutant-DNMT3B interferes with lymphoid-specific pathways resulting in immune response defects. Interestingly, recent findings report that DNMT3B shapes intragenic CpG-methylation of highly-transcribed genes. However, how the DNMT3B-dependent epigenetic network modulates transcription and whether ICF1-specific mutations impair this process remains unknown. We performed a transcriptomic and epigenomic study in patient-derived B-cell lines to investigate the genome-scale effects of DNMT3B dysfunction. We highlighted that altered intragenic CpG-methylation impairs multiple aspects of transcriptional regulation, like alternative TSS usage, antisense transcription and exon splicing. These defects preferentially associate with changes of intragenic H3K4me3 and at lesser extent of H3K27me3 and H3K36me3. In addition, we highlighted a novel DNMT3B activity in modulating the self-regulatory circuit of sense-antisense pairs and the exon skipping during alternative splicing, through interacting with RNA molecules. Strikingly, altered transcription affects disease relevant genes, as for instance the memory-B cell marker CD27 and PTPRC genes, providing us with biological insights into the ICF1-syndrome pathogenesis. Our genome-scale approach sheds light on the mechanisms still poorly understood of the intragenic function of DNMT3B and DNA methylation in gene expression regulation.

Tumor-Induced IL-6 Reprograms Host Metabolism to Suppress Anti-tumor Immunity

In patients with cancer, the wasting syndrome, cachexia, is associated with caloric deficiency. Here, we describe tumor-induced alterations of the host metabolic response to caloric deficiency that cause intratumoral immune suppression. In pre-cachectic mice with transplanted colorectal cancer or autochthonous pancreatic ductal adenocarcinoma (PDA), we find that IL-6 reduces the hepatic ketogenic potential through suppression of PPARalpha, the transcriptional master regulator of ketogenesis. When these mice are challenged with caloric deficiency, the resulting relative hypoketonemia triggers a marked rise in glucocorticoid levels. Multiple intratumoral immune pathways are suppressed by this hormonal stress response. Moreover, administering corticosterone to elevate plasma corticosterone to a level that is lower than that occurring in cachectic mice abolishes the response of mouse PDA to an immunotherapy that has advanced to clinical trials. Therefore, tumor-induced IL-6 impairs the ketogenic response to reduced caloric intake, resulting in a systemic metabolic stress response that blocks anti-cancer immunotherapy.

Preventive effects of electrical stimulation on inflammation-induced muscle mitochondrial dysfunction

Cachexia is a complex metabolic syndrome associated with underlying chronic diseases and is characterized by the overexpression of pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-α), which impair muscle oxidative metabolism. We hypothesized that electrical stimulation (ES) would prevent decrement in muscle oxidative metabolism by suppressing the phosphorylation of p38 MAPK, a critical regulator of inflammatory response. Therefore, the purpose of the present study was to verify the effects of ES on inflammatory-induced decrement of oxidative metabolism in mice tibialis anterior muscles. ICR mice were randomly divided into three groups: control, lipopolysaccharide (LPS) injection for 4days, and LPS injection plus ES (LPS+ES). Cachexia was induced in the animals in the LPS groups via LPS injection (10mg/kg body weight/day, i.p.) during the intervention period. The animals in the LPS+ES group were stimulated electrically (carrier frequency, 2500Hz; modulation frequency, 100Hz; duration, 240s/day; type of contraction, isometric) during the intervention period. LPS injection resulted in decreased body and muscle wet weight and increased expression of TNF-α in plasma and skeletal muscle. In addition, LPS injection decreased indicators of mitochondrial function such as succinate dehydrogenase (SDH) and citrate synthase (CS) activity as well as the expression of PGC-1ɑ, and increased the phosphorylation of p38 MAPK. On the other hand, the intervention of ES attenuated the changes in muscle wet weight, SDH activity, CS activity, p38 MAPK, and PGC-1ɑ. These results suggest that ES could prevent decrement in muscle oxidative metabolism induced by pro-inflammatory cytokines in cachexia.

Tumor necrosis factor involvement in the toxicity of TCDD: the role of endotoxin in the response

We have previously demonstrated that tumor necrosis factor is involved in the acute toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), since therapies designed to attenuate the effects of tumor necrosis factor resulted in reduced mortality and toxicity in mice exposed to an LD75 dose of TCDD. The current study addresses whether endotoxin may be a contributing factor in the cachexia and mortality resulting from TCDD exposure. Endotoxin-nonresponsive C3H/HeJ mice and endotoxin-responsive C57BL/6 mice were treated with 350 micrograms/kg TCDD and body weight and mortality were recorded. C3H/HeJ mice showed no trend in body weight loss (p = 0.554), while C57BL/6 mice demonstrated a statistically significant (p < 0.01) linear decline in body weight of -0.23 g/day, resulting in a net loss of 3.5 g over 15 days preceding mortality. Mortality was observed in the C57BL/6 mice beginning on day 16 with 100% of the mice dying by the 23rd day while no mortality was observed in C3H/HeJ mice until the 24th day of the study with only 22% mortality observed. These data further demonstrate that endotoxin is a contributing factor to the cachexia and lethality of TCDD.

The correlation between a chronic inflammatory marker Tartrate-resistant acid phosphatase 5a with cancer cachexia

PURPOSE

The mechanism of cancer cachexia remains unclear and inflammatory cytokines may play a role in its development. Interleukin-6 (IL-6), C-reactive protein (CRP) and tumor necrosis factor-α (TNFα) are known to be associated with cancer cachexia. Tartrate-resistant acid phosphatase 5a (TRACP5a) is proposed to be related to chronic inflammation. In this study we hypothesize that TRACP5a is a chronic inflammatory marker that is correlated with cancer cachexia.

METHODS

Fifty-five cancer patients with and without cancer cachexia were enrolled from January 2009 to December 2012. Body mass index (BMI) was measured and serum total cholesterol, triglycerides and albumin were examined to evaluate the nutritional status. IL-6, CRP and TRACP5a protein activity were evaluated.

RESULTS

Inflammatory markers including IL-6, and CRP were significantly elevated in patients with cancer cachexia (p=0.0075 and 0.0021, respectively). Patients with cachexia also had higher CRP/albumin ratio (p=0.0265). TRACP5a activity, TRACP5a protein and their combinations with albumin were increased in the cancer cachexia groups but without significant difference. There were good correlations between IL-6, CRP, and BMI. Patients with higher TRACP5a activity had shorter survival (p=0.004).

CONCLUSION

TRACP5a may be a promising chronic inflammatory marker and may play a prognostic role in cancer cachexia. Further large-scale prospective studies are warranted to confirm its role in the cancer cachexia process.

Cancer cachexia: malignant inflammation, tumorkines, and metabolic mayhem

Cachexia has a devastating impact on survival and quality of life for many cancer patients. A better understanding of the underlying mechanisms leading to the complex metabolic defects of cachexia, coupled with effective treatment options, will improve management of wasting in cancer patients. The growing appreciation that cancer cachexia results from the spillover effects of cytokine production by tumors on the integrated regulation of energy balance in different organs identifies potential therapeutic options. However, targeting such tumorkines requires a comprehensive understanding of their normal as well as pathophysiological functions, especially the crosstalk between inflammatory signaling and metabolic dysregulation. Recent advances in characterizing the surprising parallels between obesity and cancer cachexia provide new insights into these apparently divergent syndromes.

Immune neuroendocrine interactions during a fungal infection in immunocompetent or immunosuppressed hosts

The yeast Candida albicans belongs to the microflora of healthy individuals, although it can infect a variety of tissues ensuing changes in the host's immune status. To evaluate the effect of neuroendocrine input on the early immune response during the fungal infection, we use a 3-day paradigm of chronic varied stress in Wistar rats infected with C. albicans. We find that stress mediators contribute to the spread of the fungus and downregulate critical functions of phagocytic cells at the infection site. Phenotypic and functional alterations of effector cells account for the decreased resistance to candidiasis and condition the development of the adaptive response. Stressed hosts exhibit a higher fungal burden in kidneys and livers associated with hyphal forms. The hepatic inflammatory reaction is compromised with severe steatosis, increment of functional enzymes, marked lipid peroxidation and hepatocyte apoptosis. Moreover, infection-related sickness symptoms are significantly increased by exposure to stress with anorexia, weight loss, lack of leptin and depletion of glycogen depots. Food deprivation exacerbates the liver injury. Stress mediators perturb the complex immune and metabolic program that operates early during fungal spread and promotes severe tissue damage.

A clinical correlate of the dysregulated immunoendocrine response in human tuberculosis

Wasting is a prominent feature in tuberculosis (TB), but its underlying mechanisms are incompletely understood. Immunoendocrine disturbances may be linked to the consumption state of TB patients, since hormones and cytokines can affect energy expenditure and metabolism. To approach this possibility, we have determined leptin, IL-18, and adrenal steroid plasma levels and body mass index (BMI) in newly diagnosed patients with mild, moderate and severe pulmonary TB, household contacts (HHC), and healthy controls (HCO). HHC displayed higher levels of leptin than HCO and TB patients. TB patients showed a gradual decrease in BMI and leptin concentrations with increasing disease severity, whereas a positive correlation between this hormone and BMI was found in the HCO group. Cortisol concentrations tended to be higher in TB patients. DHEA levels were decreased in TB patients and to a lesser extent in HHC, whereas IL-18 concentration was significantly increased in patients with severe disease. Since HHC are known to cause a latent subclinical infection, it seems clear that controlled tuberculous infection and manifested TB disease are accompanied by a dissimilar profile of immunoendocrine markers.

Tryptophan in wasting diseases: at the crossing between immune function and behaviour

PURPOSE OF REVIEW

Wasting diseases are characterized by progressive deterioration of nutritional status that negatively influences patients' outcome. The better understanding of the pathogenic mechanisms of wasting may lead to effective therapies. Tryptophan metabolism has unique features suggesting a critical role in influencing human metabolism under normal and pathological conditions.

RECENT FINDINGS

During disease, inflammatory response favours the local depletion of the essential amino acid tryptophan, thereby inhibiting cellular proliferation. Tryptophan depletion may also mediate immunotolerance to foreign antigens. In contrast, brain accumulation of tryptophan contributes to wasting by increasing oxidative stress and hypothalamic serotonin neurotransmission, and thereby triggering the onset of sickness behaviour followed by depressive-like behaviour.

SUMMARY

Tryptophan metabolism is critical in mediating a number of important biological responses. Restoring tryptophan metabolism may well result in enhanced recovery from disease.

Rheumatoid cachexia is associated with dyslipidemia and low levels of atheroprotective natural antibodies against phosphorylcholine but not with dietary fat in patients with rheumatoid arthritis: a cross-sectional study

INTRODUCTION

Patients with rheumatoid arthritis (RA) have an increased risk for cardiovascular disease (CVD) independent of traditional risk factors. The aim of this study was to analyze the associations between diet, body composition, lipids and atheroprotective natural antibodies against phosphorylcholine (anti-PC) in patients with RA.

METHODS

A total of 80 RA patients (76% women), mean age (standard deviation (SD)) 61.4 (12) years and median disease duration of 6 years, were assessed by food frequency questionnaire (FFQ), fatty acid profile in adipose tissue and whole-body dual energy x ray absorptiometry (DXA). Rheumatoid cachexia was defined as fat free mass index below the 25th percentile and fat mass index above the 50th percentile of a reference population. Blood lipids, oxidized low-density lipoprotein (oxLDL) and anti-PC levels were determined.

RESULTS

The mean body mass index for the women and men was 25.0 and 27.0, respectively. Central obesity was found in 57% of the women (waist circumference >80 cm) and in 89% of the men (waist circumference >94 cm). In all, 18% of the women and 26% of the men had rheumatoid cachexia. These patients had significantly higher total cholesterol (P < 0.033), LDL (P < 0.029), and trendwise oxLDL (P = 0.056) as well as lower anti-PC IgM (P = 0.040), higher frequency of hypertension (69%) and metabolic syndrome (25%) than those without. The patients reported a high dietary intake of saturated fat, which partly correlated with fatty acid composition in adipose tissue and significantly with disease activity. However, patients with or without cachexia did not differ with respect to dietary fat intake or intake of Mediterranean-like diet. Additionally, patients on a Mediterranean-like diet had high levels of anti-PC (P < 0.001).

CONCLUSIONS

About one in five patients with low-active RA displayed rheumatoid cachexia. This condition was associated with high levels of LDL cholesterol, low levels of atheroprotective anti-PC and high frequency of hypertension, which is of interest in the context of CVD in RA. The cachexia could not be related to diet fat intake. However, patients on a Mediterranean-like diet had high anti-PC levels in spite of similar frequency of cachexia. High anti-PC levels may provide some protection against CVD.

Liver macrophages contribute to pancreatic cancer-related cachexia

Cachexia is a devastating process especially in pancreatic cancer patients and contributes to their poor survival. We attempted to clarify the pathological and molecular changes that occur in the liver during the development of cachexia. Using immunohistochemistry we investigated the infiltration of inflammatory mononuclear cells in liver biopsies of pancreatic cancer patients with or without cachexia, and the potential relevance of the cells for the nutritional and inflammatory status. Additionally, these findings were compared with the patients' clinical parameters. We found a significantly higher amount of CD68 immunoreactive macrophages in liver cross sections of patients with pancreatic cancer and cachexia. The number of CD68-positive macrophages was significantly inversely correlated with the nutritional status. Additionally, in these CD68-positive areas a significant increase in IL-6 and IL-1 immunoreactive cells was localized. Moreover, we found significantly increased areas of CD68-positive macrophages in liver biopsies of patients with a more dedifferentiated (aggressive) grading of the tumor. In conclusion, these results suggest that a crucial interaction between the tumor, PBMCs, and the liver may play a central role in the development and regulation of cachexia. Furthermore, pancreatic cancer may be able to alter systemic organ function even without obvious metastatic disease.

Cardiac cachexia: a systematic overview

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

A novel role for CD4+ T cells in the control of cachexia

Cachexia is the dramatic weight loss and muscle atrophy seen in chronic disease states, including autoimmunity, cancer, and infection, and is often associated with lymphopenia. We have previously shown that CD4(+) T cells that express the lowest density of CD44 (CD4(+)CD44(v.low)) are significantly reduced in diabetic NOD mice that are cachexic compared with diabetic mice that are not cachexic. Using this model, and a model of cancer cachexia, we test the hypothesis that CD4(+)CD44(v.low) cells play an active role in protecting the host from cachexia. CD4(+)CD44(v.low) cells, but not CD4(+) cells depleted of CD44(v.low) cells, delay the onset of wasting when infused into either diabetic or prediabetic NOD recipients. However, no significant effect on the severity of diabetes was detected. In a model of cancer cachexia, they significantly reduce muscle atrophy, and inhibit muscle protein loss and DNA loss, even when given after the onset of cachexia. Protection from wasting and muscle atrophy by CD4(+)CD44(v.low) cells is associated with protection from lymphopenia. These data suggest, for the first time, a role for an immune cell subset in protection from cachexia, and further suggest that the mechanism of protection is independent of protection from autoimmunity.

Ghrelin treatment of chronic kidney disease: improvements in lean body mass and cytokine profile

Chronic kidney disease (CKD) is associated with an increase in inflammatory cytokines and can result in cachexia with loss of muscle and fat stores. We previously demonstrated the efficacy of treating a model of cancer cachexia with ghrelin and a ghrelin receptor agonist. Currently, we examine a surgical model of CKD in rats, resulting in uremia and decreased accrual of lean body mass. Treatment with ghrelin and two ghrelin receptor agonists (BIM-28125 and BIM-28131) resulted in increased food intake and an improvement in lean body mass accrual that was related in part to a decrease in muscle protein degradation as assessed by muscle levels of the 14-kDa actin fragment resulting from cleaved actomyosin. Additionally, there was a decrease in circulating inflammatory cytokines in nephrectomized animals treated with ghrelin relative to saline treatment. Ghrelin-treated animals also had a decrease in the expression of IL-1 receptor in the brainstem and a decrease in expression of prohormone convertase-2, an enzyme involved in the processing of proopiomelanocortin to the anorexigenic peptide alpha-MSH. We conclude that ghrelin treatment in uremia results in improved lean mass accrual in part due to suppressed muscle proteolysis and possibly related to antiinflammatory effects.

Association of IL-6 gene polymorphisms with cachexia susceptibility and survival time of patients with pancreatic cancer

The purpose of this study was to determine the predictive value of IL-6-572, -190, and -634 gene polymorphisms on the cachexia susceptibility and survival time of patients with pancreatic cancer. Genotypes were determined using restriction fragment length polymorphism analysis of polymerase chain reaction products. All of the subjects were homozygous to the C allele of IL-6-190. No significant differences were found in the IL-6-572G and -190C distributions between the cachexia group and the non-cachexia group. Patients with cachexia showed significantly higher prevalence of common bile duct obstruction (CBD) than those without (p = 0.026). A significantly increased frequency of the IL-6-634G allele was noted in the cachexia group vs the non-cachexia group (p = 0.021). Logistic regression adjusted for sex, age, duodenal obstruction, and CBD obstruction, the IL-6-634 CG + GG genotype was associated with an odds ratio of 2.785 (1.034, 7.501) for cachexia. Patients with IL-6-634 CG + GG carrier showed shorter duration of survival than those with CC genotype (p = 0.023). These results indicate that the IL-6-634G allele is associated with increased susceptibility to cachexia and decreased survival time of Chinese patients suffering from pancreatic cancer.

Cachexia in chronic kidney disease: role of inflammation and neuropeptide signaling

PURPOSE OF REVIEW

This review will update clinicians and basic scientists who are interested in the clinical relevance and molecular mechanism of uremic cachexia. Recent studies that examine the role of cytokines and hypothalamic neuropeptides are emphasized.

RECENT FINDINGS

A current hypothesis of the cause of cachexia in chronic illness is that proinflammatory cytokines, such as tumor necrosis factor-alpha, interleukin-6, and leptin, act on the central nervous system to alter the release and function of several key neurotransmitters, thereby altering both appetite and metabolic rate. Proinflammatory cytokines also activate the transcription factor nuclear factor-kappaB, resulting in decreased protein synthesis, and activate the ubiquitin-mediated proteolytic system, which is the major system involved in increased protein degradation.

SUMMARY

This review highlights the importance of melanocortin signaling in the pathogenesis of uremia-associated cachexia and the potential of peripheral administration of melanocortin-4 receptor antagonists as a novel therapeutic approach.

Regulation of food intake by inflammatory cytokines in the brain

A number of inflammatory cytokines are synthesized and released after activation of the immune system. In addition to other biological effects, these cytokines can potently inhibit food intake. Cytokine-mediated inhibition of food intake is of particular importance because excessive production of peripheral inflammatory cytokines is often associated with the cachexia-anorexia syndrome seen in some chronic diseases. The weight loss in cachexia is associated with an increase in morbidity and mortality. Understanding how cytokines regulate food intake may be crucial in enhancing quality of life and facilitating recovery in patients exhibiting cachexia. This review describes the main inflammatory cytokines that influence food intake and explores how peripheral cytokines communicate with hypothalamic nuclei to influence feeding.

Anorexia in chronic obstructive pulmonary disease--association to cachexia and hormonal derangement

BACKGROUND

In patients with chronic obstructive pulmonary disease (COPD) weight loss frequently occurs that may ultimately lead to cachexia as a serious co-morbidity, indicating severely impaired functional capacity, health status and increased mortality. Increased energy expenditure due to mechanic and metabolic inefficiency and systemic inflammation are determinants of a hypermetabolic state that is not balanced by dietary intake. Anorexia may importantly contribute to weight loss in COPD, however, the association between immune and hormonal derangement and altered appetite has not been studied in detail.

AIM

The aim of the present study was to investigate whether anorexia in COPD is related to inflammation and hormonal derangement in association to weight loss.

METHODS

We prospectively enrolled 103 consecutive patients with COPD (age 59.8+/-1.3 years, 35% female, mean FEV1 38.3+/-1.7%) in comparison to healthy controls of similar age (n=15).

RESULTS

In 34 patients (33%) cachexia was diagnosed (weight loss >7.5%, BMI < or = 24 kg/m2). Cachectic COPD patients had lower BMI (19.0+/-0.5 vs 25.6+/-0.7 kg/m2) and impaired lung function (FEV1 31+/-2% vs 42+/-2%, FVC 51+/-3 vs 59+/-3%, both p<0.001). Inflammatory immune activation (IL-6 and IL-6/IL-10 ratio) was significantly higher in cachectic COPD patients. Analysis of the extent of anorexia (visual analogue scale) revealed that cachectic COPD patients had significantly decreased subjective desire to eat compared to non-cachectic patients (3.5+/-0.3 vs 6.3+/-0.2, p<0.001). Patients with COPD and cachexia showed evidence of acquired GH resistance (decreased IGF-1/GH ratio) and insulin resistance (HOMA). Anorexia showed a direct correlation with the IGF-1/GH ratio (r=0.34, p<0.05) and was further related to BMI and % weight loss (both p<0.001).

CONCLUSION

In COPD anorexia relates to hormonal derangement and inflammatory immune activation. Anorexia contributes to development of cachexia. The concept of appetite stimulating therapy emerges as a novel therapeutic option in cachectic COPD patients.

Role of intestinal function in cachexia

PURPOSE OF REVIEW

Cachexia is a prominent feature in many chronic diseases, but its pathogenesis is still not fully understood. This article reviews recent research into the role of the gut barrier in the pathogenesis of inflammation and cachexia with special emphasis on two potentially catabolic diseases: liver cirrhosis and chronic heart failure.

RECENT FINDINGS

There is increasing evidence that catabolic diseases such as liver cirrhosis and chronic heart failure are associated with increased gut permeability, endotoxemia and enhanced expression of proinflammatory cytokines. In liver cirrhosis normalization of portal hypertension by insertion of a transjugular intrahepatic portosystemic stent shunt obviously causes improvement not only of gut barrier function, but also of nutritional status.

SUMMARY

Although its pathogenesis is not yet completely understood, proinflammatory cytokines have been implicated in the onset and progression of cachexia. Recent data support the hypothesis that impaired gut barrier function and increased permeability further translocation of endotoxins. Increased endotoxemia might be a potent trigger of systemic inflammatory response which is involved in the pathogenesis of the cachexia syndrome. Thus, it is tempting to speculate that therapeutic strategies for the improvement of gut barrier function will concomitantly improve nutritional status.

The effects of chronic immune stimulation on muscle growth in rainbow trout

Successful production of aquaculture species depends on efficient growth with low susceptibility to disease. Therefore, selection programs have focused on rapid growth combined with disease resistance. However, chronic immune stimulation diminishes muscle growth (a syndrome referred to as cachexia), and decreases growth efficiency in production animals, including rainbow trout. In mammals, recent results show that increased levels of pro-inflammatory cytokines, such as those seen during an immune assault, specifically target myosin and MyoD and inhibit muscle growth. This suggests that increased disease resistance in fish, a desired trait for production, may actually decrease the growth of muscle, the main aquacultural commodity. To test this possibility, a rainbow trout model of cachexia was developed and characterized. A six-week study was conducted in which rainbow trout were chronically immune stimulated by repeated injections of LPS. Growth indices were monitored, and whole body and muscle proximate analyses, real-time PCR, and Western blotting were conducted to examine the resulting cachectic phenotype. Muscle ratio was decreased in fish chronically immunostimulated, however expression levels of MyoD2 and myosin were not decreased compared to fish that were not immunostimulated, indicating that while muscle accretion was altered, the mechanism by which it occurred was somewhat different than that characterized in mammals. Microarray analysis was used to compare gene expression in fish that had been chronically immunostimulated versus those that had not to identify possible alternative mechanisms of cachexia in fish.

Impact of TNF-α and IL-6 Levels on Development of Cachexia in Newly Diagnosed NSCLC Patients

OBJECTIVES

We investigated the role of cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in cachexia development in newly diagnosed nonsmall cell lung cancer (NSCLC) patients.

METHODS

: We evaluated 44 (M/F:41/3) NSCLC patients and 12 (M/F:10/2) age matched healthy smokers. NSCLC cases with a weight loss of > or =10% consisted the cachectic group (n:23, M/F:21/2) and the ones with <10% weight loss consisted the noncachectic group (n:21, M/F:19/2).

RESULTS

Body mass index (BMI) of cachectics was significantly lower than that of noncachectics (21.0 +/- 2.9 versus 24.5 +/- 3.6, P = 0.02) and controls (21.0 +/- 2.9 versus 25.5 +/- 2.6, P = 0.01). Serum TNF-alpha level did not differ between cachectic and noncachectics (37.3 +/- 39.1 and 51.6 +/- 84.2 pg/mL, respectively). However, it was significantly higher in NSCLC patients compared with controls (44.1 +/- 64.3 and 15.1 +/- 14.3 pg/mL, P = 0.03). Serum IL-6 level was not different between 3 groups (6.4 +/- 4.1, 8.9 +/- 16.3, and 4.1 +/- 3.5 pg/mL, respectively) but it correlated significantly with TNF-alpha (r = 0.4, P = 0.006) and BMI (r = -0.3, P = 0.03). Erythrocyte sedimentation rate (ESR) correlated significantly with TNF-alpha (r = 0.4, P = 0.003) and BMI (r = -0.3, P = 0.03). Among 44 cases, survival of 12 and 17 patients was recorded in cachectics and noncachectics, with no statistical difference (12.2 +/- 3.7 and 11.2 +/- 1.0 months, respectively).

CONCLUSIONS

TNF-alpha and IL-6 levels did not differ significantly between cachectics and noncachectics. However, significant correlations between IL-6, BMI, and TNF-alpha suggested that these cytokines acted as cofactors in weight loss. Survival was neither influenced by BMI, nor the cytokine levels in the present study. The significant correlation of ESR with TNF-alpha suggested that ESR could provide valuable clue for considerable weight loss in the follow-up of NSCLC patients.

Clodronate alleviates cachexia and prolongs survival in nude mice xenografted with an anaplastic thyroid carcinoma cell line

Cancer cachexia is one of the most common manifestations of advanced malignant disease and is frequently associated with decreased survival. Previously, we reported the establishment of a new anaplastic thyroid carcinoma cell line, Thena, and its mouse xenograft, Thena-Nu, which induced cachexia in athymic nude mice. Subsequent studies showed that the addition of clodronate to Thena-Nu cultures reduced cell proliferation as well as cytokine production in a dose- and time-dependent manner. Weekly administration of clodronate induced tumor cytostasis, attenuation of cachexia, as well as prolongation of survival in Thena-Nu-bearing mice. Reduced serum interleukin 6, tumor necrosis factor-alpha, and granulocyte colony stimulating factor levels were detected, whereas, serum leukemia inhibitory factor levels were not reduced. Liver necrosis, observed in tumor-bearing mice, was also improved following clodronate treatment. Discontinuation of clodronate treatment, however, resulted in progressive tumor growth and weight loss. Our results demonstrated that clodronate could exert therapeutic efficacy on amelioration of cancer cachexia in the hosts. Nevertheless, this study also points out that a longer period of treatment is required to maintain these effects.

[Pathophysiology of neoplasic cachexia]

The regulation of food intake is mediated by different psicological, gastrointestinal metabolic, nutritional and endocrine mechanisms. The cancer patient suffers from anorexia which results in early saciety and a reduction of appetite. Sometimes, the causes of the anorectic response are derived from the antitumoral treatment (chemotherapy, radiotherapy or immunotherapy), in some cases vomiting resulting in altered food intake. Alterations in the food taste and smell perception in addition to psychological dearrangements might also lead to the anorexia. Sometimes the tumour may play a direct effect when it is localised in either the hypothalamus or the digestive apparatus. However, in the majority of cases the origin of the anorexia associated with cancer cachexia seems to be due to the metabolic alterations induced by tumour burden. Different factors of both humoral and tumoral origin play a role in cancer anorexia. For instance, tumour necrosis factor (TNF-), a cytokine responsible for a great part of the metabolic alterations characteristic of cancer cachexia seems to be involved. In conclusion, the cancer anorexia seems to be more an effect than the cause of the weight loss and in fact the decrease in food intake might take place after weight loss is evident. In any case, the malnutrition associated with a decrease of food intake worsens the cachectic state, favouring a kind of a positive feed-back mechanism that finally leads to the patient's death.

Metabolic and immunologic derangements in cardiac cachexia: where to from here?

The onset of cardiac cachexia is characterized by a defined severe weight loss in patients with advanced chronic heart failure and it predicts an increased mortality in these patients. Recent studies with potential therapeutics investigated the effects and efficiency of beta-blockers, ghrelin, or ghrelin-agonists in cachexia. These and other new studies, like the influence of heart transplantation on cardiac cachexia, give prospect into potential therapeutic options in the future. General aim of the treatment strategy is to prevent the onset and retard the progress of cachexia. This could be achieved by modifying the metabolic, neurohormonal and immune system abnormalities, e.g. with beta-blockers and angiotensin-converting enzyme inhibitors. However, these alterations interact in a complex pathophysiological process, which is supposed to end in a vicious circle and thereby the wasting process is further promoted. To interrupt this, an early start of therapy is important to decelerate the development of cardiac cachexia. Many further investigations are needed to find out more about the pathophysiological pathways, to confirm the previous results, and to evaluate new therapeutics.

Effect of fish oil supplementation for 2 generations on changes in macrophage function induced by Walker 256 cancer cachexia in rats

The effect of coconut fat (rich in medium saturated fatty acids) or fish oil (rich in omega-3 polyunsaturated fatty acids) supplementation for 2 generations on tumor growth, cancer cachexia, animal survival and macrophage function was investigated in Walker 256 tumor-bearing rats. Female Wistar rats were supplemented with coconut fat or fish oil prior to mating and then throughout pregnancy and gestation. Both supplementations were daily and orally given at 1 g per kg body weight as a single bolus. Same treatment was performed by the 2 following generations. At 90 days of age, male offspring (50%) from F2 generation were subcutaneously inoculated with 2 x 10(7) Walker 256 tumor cells. At 14 days after tumor implantation, rats not supplemented displayed cancer cachexia characterized by loss of body weight, hypoglycemia, hyperlacticidemia, hypertriglyceridemia, decreased food intake and depletion of glycogen stores in the liver and skeletal muscles. Supplementation with coconut fat did not affect these parameters. However, supplementation with fish oil decreased tumor growth (59%), prevented body weight loss and food intake reduction and attenuated cancer cachexia. In addition, fish oil increased animal survival up to 20 days (from 25% in rats not supplemented to 67% in rats supplemented with fish oil) and improved macrophage function characterized by increased phagocytosis capacity and production of hydrogen peroxide and nitric oxide. These results suggest that fish oil supplementation for 2 generations improves macrophage function in association to reduced tumor growth and attenuated cancer cachexia, maintaining food intake and increasing animal survival.

Cytokines as mediators and targets for cancer cachexia

The cachexia syndrome, characterized by a marked weight loss, anorexia, asthenia and anaemia, is invariably associated with the growth of a tumour and leads to a malnutrition status caused by the induction of anorexia or decreased food intake. In addition, the competition for nutrients between the tumour and the host results in a state of accelerated catabolism, which promotes severe metabolic disturbances in the patient. The search for the cachectic factor(s) started a long time ago, and many scientific and economic efforts have been devoted to its discovery, but we are still a long way from a complete answer. The present review aims to evaluate the different molecular mechanisms and catabolic mediators (both humoural and tumoural) that are involved in cancer cachexia and to discuss their potential as targets for future clinical investigations.

Myofiber degeneration/regeneration is induced in the cachecticApcMin/+mouse

Cachexia is characterized as an inflammatory state induced by the cancer environment, which is accompanied by the loss of muscle and fat mass. Well-investigated mechanisms of cachexia include the suppression of myofiber protein synthesis and the induction of the protein degradation. However, it is not well characterized whether chronic inflammation during cachexia induces myofiber degeneration, which contributes to muscle mass loss and decreased functional capacity. The purpose of this study was to determine whether Apc(Min/+) mice, which demonstrate a chronic systemic inflammatory state due to an intestinal tumor burden, undergo cachexia and whether the myofibers exhibit signs of degeneration and/or regeneration. Six-month-old female Apc(Min/+) body weight decreased 21% compared with C57BL/6 mice and was not the result of blunted growth. Apc(Min/+) gastrocnemius muscle was reduced 45%, and soleus mean fiber cross-sectional area decreased 24% vs. C57BL/6 mice. Soleus muscle morphology demonstrated pathology of myofibers undergoing degeneration and/or regeneration. These data demonstrate that the Apc(Min/+) mouse becomes cachectic by 6 mo of age and that skeletal muscle degeneration and regeneration may be related to the muscle loss.

CNTO 328, a monoclonal antibody to IL-6, inhibits human tumor-induced cachexia in nude mice

IL-6 is a multifunctional cytokine implicated in several cancers. IL-6 is a growth factor for certain tumors and contributes to drug resistance, cachexia and bone resorption. Cachexia is characterized by progressive weight loss and depletion of host reserves of adipose tissue and skeletal muscle. We have developed CNTO 328 (cCLB8), a human-mouse chimeric MAb to IL-6 (K(d) approx. 10(-12) M) that inhibits IL-6 function. A phase I study with CNTO 328 in multiple myeloma patients demonstrated that the antibody was safe and had a circulating half-life of approximately 17 days. Since IL-6 is implicated in cachexia, we hypothesized that CNTO 328 could inhibit tumor-induced cachexia. We used 2 human tumor-induced cachexia models in nude mice. In the first model, human melanoma cells were inoculated in female nude mice. Control treated animals lost 19% (+/-7.7%) body weight from day 0 to day 31, whereas CNTO 328 (10 mg/kg)-treated animals lost only 1.5% (+/-1.3%) body weight from day 0 to day 31 (p = 0.023). In the second cachexia model, human prostate tumor cells were injected into male nude mice. By day 29, control treated animals lost 6% (+/-3.5%) body weight, whereas CNTO 328 (10 mg/kg)-treated animals gained 7% (+/-4%) body weight (p = 0.01). Since CNTO 328 blocks human IL-6 but not mouse IL-6, the data indicate that tumor cell-secreted IL-6 directly contributes to body weight loss, highlighting the potential role for CNTO 328 as an anticachectic agent.

Tumor necrosis factor-alpha production is associated with less body cell mass in women with rheumatoid arthritis

OBJECTIVE

To examine the relationship between inflammatory cytokine production and body cell mass (BCM) in women with stable, medically well-controlled rheumatoid arthritis (RA).

METHODS

Case-control study of 20 women with RA and 20 healthy women matched for age, race, and body mass index (kg/m2). Tumor necrosis factor-alpha (TNF-alpha), interleukin 1beta (IL-1beta), and IL-6 production were measured by specific, non-cross-reacting ELISA of peripheral blood mononuclear cells (PBMC) cultured with and without 100 ng/ml of endotoxin. Total BCM was assessed by the reference method of whole-body counting of naturally occurring radioactive potassium-40.

RESULTS

Patients with RA were cachectic, with 14% less BCM (p < 0.001) and higher TNF-alpha production (p < 0.05) than controls. TNF-alpha production was inversely associated with BCM both without (r = -0.51, p = 0.03) and with (r = -0.57, p = 0.01) endotoxin stimulation in patients but not in controls. In multivariate linear regression models, these inverse associations remained significant after adjustment for age and physical activity. No association was found for IL-1beta or IL-6 production in these models.

CONCLUSION

Women with stable, medically well-controlled RA have lower than normal BCM that is inversely associated with elevated TNF-alpha production.

Rethinking nutritional support for persons with cancer cachexia

Cancer cachexia is a poorly understood syndrome of anorexia, weight loss, and muscle wasting that negatively impacts quality of life and survival in cancer patients. Research has clearly implicated pro-inflammatory cytokines in the biology of cancer cachexia. More recent research implicates products of arachidonic acid and suggests that cachexia may be a chronic inflammatory condition rather than a nutritional aberration. To date, nutritional support to slow weight loss has focused primarily on increasing calorie intake. Alternatively, many foods contain factors that can modulate the synthesis or activity of pro-inflammatory mediators, especially the synthesis of prostaglandin E2 from arachidonic acid. These factors and foods are sometimes called nutraceuticals, and research is needed to evaluate their efficacy in combating cancer cachexia.

Reconstitution of Lethally Irradiated Adult Mice with Dominant Negative TGF-β Type II Receptor-Transduced Bone Marrow Leads to Myeloid Expansion and Inflammatory Disease

TGF-beta regulation of immune homeostasis has been investigated in the context of cytokine knockout (TGF-beta null) mice, in which particular TGF-beta isoforms are disrupted throughout the entire organism, as well as in B and T cell-specific transgenic models, but to date the immunoregulatory effects of TGF-beta have not been addressed in the context of an in vivo mouse model in which multi-isoform TGF-beta signaling is abrogated in multiple leukocyte lineages while leaving nonhemopoietic tissue unaffected. Here we report the development of a murine model of TGF-beta insensitivity limited to the hemopoietic tissue of adult wild-type C57BL/6 mice based on retroviral-mediated gene transfer of a dominant negative TGF-beta type II receptor targeting murine bone marrow. Unlike the lymphoproliferative syndrome observed in TGF-beta1-deficient mice, the disruption of TGF-beta signaling in bone marrow-derived cells leads to dramatic expansion of myeloid cells, primarily monocytes/macrophages, and is associated with cachexia and mortality in lethally irradiated mice reconstituted with dominant negative receptor-transduced bone marrow. Surprisingly, there was a notable absence of T cell expansion in affected animals despite the observed differentiation of most cells in the T cell compartment to a memory phenotype. These results indicate not only that TGF-beta acts as a negative regulator of immune function, but that lack of functional TGF-beta signaling in the myeloid compartment of adult mice may trigger suppression of lymphocytes, which would otherwise proliferate when rendered insensitive to TGF-beta.

Chronic heart failure: an example of a systemic chronic inflammatory disease resulting in cachexia

Chronic heart failure is no longer a mere cardiac entity, but involves several, initially adaptive and later detrimental, neurohumoral compensatory mechanisms. Peripheral manifestations of the disease, such as endothelial dysfunction, skeletal muscle changes, and disturbances in ventilatory control, are major determinants of symptoms. The independent prognostic value and the relevance of cachexia on morbidity of patients with chronic heart failure have only recently been recognised. Altered body composition in heart failure patients is reflected in the early loss of muscle tissue but affects all tissue compartments in case of cardiac cachexia. Recently, a new portfolio of biologically active molecules, termed cytokines, have been shown to play an important role in the development and progression of both cardiac and peripheral abnormalities. Similar to other chronic illnesses, covered in the remainder of this issue, a low-grade chronic inflammatory process may be of particular relevance in the development of tissue wasting in these patients. Whereas the presence of immune activation in chronic heart failure is now widely accepted, as well as the prognostic relevance of chronic inflammation, the site and the source of cytokine production remain the object of intense research. Although the inciting event is located in the heart, cross-talk between the myocardium on the one hand, and the immune system, peripheral tissues and organs on the other hand, will lead to the overproduction of proinflammatory cytokines and, inevitably, to their detrimental effects. The specific problems related to heart failure progression and inflammatory activation are described in this review.

In vivo gene transfer of murine interleukin-4 inhibits colon-26-mediated cancer cachexia in mice

Cancer cachexia has been suggested to be mediated by various cytokines derived either from tumor or host tissue. In the murine colon-26 (C-26) adenocarcinoma model IL-1, secreted by tumor-infiltrating mononuclear phagocytes, has an important role in induction of cancer cachexia. In order to suppress production of IL-1 in peritoneal macrophages we have used liposome-mediated gene transfer of the anti-inflammatory cytokine mIL-4, known as a potent inhibitor of IL-1 production. Balb/c mice were transfected by intraperitoneal inoculation of C-26 tumor cells. The mIL-4 transfected animals showed increased survival rate, delayed symptoms of cachexia and reduced anorexia in comparison with tumor-bearing control groups. However, tumor growth inhibition was not seen in mIL-4-transfected animals. Peritoneal macrophages from surviving mIL-4-transfected mice, when stimulated with LPS ex vivo, showed decreased IL-1 alpha production, 1672 +/- 202 pg/2 x 10(6) cells in contrast to tumor-bearing control animals, 3975 +/- 89 pg/2 x 10(6) cells, mock-transfected tumor-bearing animals 4004 +/- 174 pg/2 x 10(6) cells and tumor-free animals, 3142 +/- 60 pg/2 x 10(6) cells (p < 0.004). The present study demonstrates that in vivo gene transfer of an anti-inflammatory cytokine reduces cancer-associated cachexia by inhibition of IL-1 alpha production of tumor surrounding peritoneal macrophages, without a significant effect on tumor growth.

What is the role of the insulin-like growth factor system in the pathophysiology of cancer cachexia, and how is it regulated?

OBJECTIVE AND BACKGROUND

The cancer cachexia syndrome is characterized by anorexia, weight loss with muscle wasting and increased energy expenditure. It is associated with increased morbidity and mortality, but its aetiology is poorly understood and no effective therapeutic intervention is available. It may result from an imbalance between the activity or effect of anabolic and catabolic hormones, mediated by the inflammatory cytokines. IGF-I is a potent anabolic agent, with therapeutic potential. Our objective was to investigate the role and regulation of the IGF system in cancer cachexia.

DESIGN AND PATIENTS

We set up a prospective study of 30 patients with newly diagnosed unresectable non-small cell lung cancer, together with a cross-sectional comparison group of healthy volunteers.

MEASUREMENTS

We examined the relationship between aspects of the IGF system, including IGFBP-3 proteolysis (using Western ligand and immunoblotting and an in vitro IGFBP-3 protease assay); the inflammatory cytokines and their soluble receptors; and food intake and nutritional status (including biochemical and anthropometric assessments).

RESULTS

Although we did not observe a marked reduction in food intake in the cancer patients, the majority lost weight and functionally important lean body mass. We observed GH resistance in the cancer patients, and intermittent proteolysis of IGFBP-3, which correlated with the circulating interleukin-6 (IL-6) concentration. The pattern of IGFBP-3 proteolysis was unusual, with a prominent 17-kDa fragment. Less IGFBP-3 proteolysis was associated with more weight loss, suggesting that this could be a protective counter-regulatory mechanism, increasing IGF-I bioavailability to the tissues.

CONCLUSIONS

Cancer cachexia in humans is a complex condition. Patients tend to be GH resistant. The significance of the intermittent increases in IGFBP-3 proteolysis, which may be regulated by IL-6, remains uncertain. A better understanding of the pathophysiology should enable the development of novel therapeutic approaches.

Decreased production of interleukin-12 and type 2 immune responses are marked in cachectic patients with colorectal and gastric cancer

Balance of the two types of T helper cells is one of the most important factors for regulation of the immune system. This study examines the production of interleukin (IL)-4, -6, -10, -12, and interferon-gamma by peripheral blood mononuclear cells stimulated with phytohemagglutinin or Staphylococcus aureus. Sixty-one patients, including 25 with gastric and 39 with colorectal cancer, and 39 normal volunteers were entered. The production of IL-12 decreased significantly with advancing disease and was lowest in the patients with distant metastases and cachexia. Compared with normal donors, the production of interferon-gamma decreased in all categories of patients, with no difference among patient groups. Levels of Th2 cytokines, such as IL-4, IL-6, and IL-10, also showed no difference among patient groups. However, production of all these cytokines had increased by 2.5 months after sequential testing in the same cachectic patients. The authors' findings indicate that the induction of Th1 cells seems to be suppressed at a relatively early stage of disease, whereas that of Th2 cells seems to increase in the terminal stage.

IL-6-like cytokines and cancer cachexia: consequences of chronic inflammation

An estimated 30% of cancer deaths are attributed to cachexia and its consequences. Cachexia (wasting syndrome) is the hypercatabolism of the body's carbon sources, proteins and lipids, for conversion into energy. It is induced by a variety of pathological conditions, including cancer. Among the inflammatory responses to cancer is the synthesis of cytokines, including IL-6 and related cytokines. These cytokines have been found to induce cachexia by altering metabolism of lipids and proteins. IL-6-like cytokines have been found to inhibit lipid biosynthesis by adipocytes, which increased the rate of lipid catabolism. Others have described the atrophy and increased catabolism of muscle protein due to IL-6. A cytokine closely-related to IL-6 is leptin, which plays a major role in lipid metabolism under normal conditions. The role of leptin in pathological conditions such as cancer cachexia has not yet been fully elucidated. Detailed mechanistic information about the induction of cancer cachexia by IL-6-like cytokines requires more research.

Glutamine supplementation in cancer patients

OBJECTIVES

Three series of studies investigated whether 1) glutamine deficiency occurs in tumor-bearing rats, 2) glutamine supplementation improves protein metabolism during chemotherapy in tumor-bearing rats, and 3) oral glutamine supplement improves systemic immune and gut-barrier function in patients with esophageal cancer receiving radiochemotherapy.

METHODS

In the animal studies, AH109A hepatoma cells or Yoshida sarcoma cells were inoculated into male Donryu rats to induce tumors. Glutamine production was measured by U-14C-glutamine infusion and the conversion of arginine to glutamine was measured by infusion of U-14C-arginine. The effect of glutamine on protein metabolism was investigated by 1-14C-leucine infusion. In the clinical study, 13 patients with esophageal cancer were randomized into two groups, control and glutamine supplemented (30 g/d), for 4 wk.

RESULTS

Glutamine levels in plasma and skeletal muscle were decreased in tumor-bearing rats, although glutamine production and the conversion of arginine to glutamine were increased. Glutamine-supplemented total parenteral nutrition reduced whole-body protein breakdown rate during chemotherapy in tumor-bearing rats. Oral supplementation of glutamine to the patients with esophageal cancer enhanced lymphocyte mitogenic function and reduced permeability of the gut during radiochemotherapy.

CONCLUSIONS

Glutamine depletion in host tissues occurs in tumor-bearing rats. Glutamine supplementation can attenuate loss of protein in the muscle in tumor-bearing animals and protect immune and gut-barrier function during radiochemotherapy in patients with advanced cancer.