Evidence for a novel serum factor distinct from zinc alpha-2 glycoprotein that promotes body fat loss early in the development of cachexia

Abnormal lipid metabolism in cancer-associated cachexia and potential therapy strategy

Cancer-associated cachexia (CAC) is a major characteristic of advanced cancer, associates with almost all types of cancer. Recent studies have found that lipopenia is an important feature of CAC, and it even occurs earlier than sarcopenia. Different types of adipose tissue are all important in the process of CAC. In CAC patients, the catabolism of white adipose tissue (WAT) is increased, leading to an increase in circulating free fatty acids (FFAs), resulting in " lipotoxic". At the same time, WAT also is induced by a variety of mechanisms, browning into brown adipose tissue (BAT). BAT is activated in CAC and greatly increases energy expenditure in patients. In addition, the production of lipid is reduced in CAC, and the cross-talk between adipose tissue and other systems, such as muscle tissue and immune system, also aggravates the progression of CAC. The treatment of CAC is still a vital clinical problem, and the abnormal lipid metabolism in CAC provides a new way for the treatment of CAC. In this article, we will review the mechanism of metabolic abnormalities of adipose tissue in CAC and its role in treatment.

Impact of dietary walnuts, a nutraceutical option, on circulating markers of metabolic dysregulation in a rodent cachectic tumor model

Background:

Nutraceutical foods, like walnuts which are rich in immunonutrients, can have medicinal benefits. Dietary walnuts have been shown to slow or prevent tumor growth in mice genetically programmed to grow breast or prostate tumors. This study investigated whether walnuts could exert the same preventable effect in a transplantable carcinoma rat model.

Methods:

Eighteen rats were randomly fed a diet containing walnuts (10% of food by weight), and 36 were fed a diet without walnuts (control) for 21 days. On day 22, 18 control diet rats were switched to the walnut diet. All other animals remained on their same diet. Within each diet group, 6 rats were implanted with the Ward colon carcinoma (TB), and 12 were sham-operated. Five days later, 6 sham-operated animals were weight-matched to a TB and then pair-fed for the remainder of the study. The remaining 6 sham-operated, or non-tumor-bearing rats, were ad-lib fed.

Results:

The tissue of the walnut-eating rats showed higher omega-3 fatty acid (immunonutrient) content which did not slow or prevent tumor growth or the loss of lean and fat mass typical of this TB model. In addition, blood glucose, insulin, IGF-1, and adiponectin levels were significantly lower in the TB, demonstrating metabolic dysregulation. Again, these changes were unaltered by consuming walnuts. Plasma proteomics identified six proteins elevated in the TB, but none could be connected with the observed metabolic dysregulation.

Conclusion:

Although walnuts’ rich immunonutrient content prevented tumor growth in genetically programmed mice models, there was no effect in this model.

3D bioprinted white adipose model for in vitro study of cancer-associated cachexia induced adipose tissue remodeling

Cancer-associated cachexia (CAC) is a complex metabolic and behavioral syndrome with multiple manifestations that involve systemic inflammation, weight loss, and adipose lipolysis. It impacts the quality of life of patients and is the direct cause of death in 20-30% of cancer patients. The severity of fat loss and adipose tissue remodeling negatively correlate with patients' survival outcomes. To address the mechanism of fat loss and design potential approaches to prevent the process, it will be essential to understand CAC pathophysiology through white adipose tissue models. In the present study, an engineered human white adipose tissue (eWAT) model based on three-dimensional (3D) bioprinting was developed and treated with pancreatic cancer cell-conditioned medium (CM) to mimic the status of CAC in vitro. We found that the CM treatment significantly increased the lipolysis and accumulation of the extracellular matrix (ECM). The 3D eWATs were further vascularized to study the influence of vascularization on lipolysis and CAC progression, which was largely unknown. Results demonstrated that CM treatment improved the angiogenesis of vascularized eWATs (veWATs), and veWATs demonstrated decreased glycerol release but increased Ucp1 expression, compared to eWATs. Many unique inflammatory cytokines (IL-8, CXCL-1, GM-CSF, etc) from the CM were detected and supposed to contribute to eWAT lipolysis, Ucp1 up-regulation, and ECM development. In response to CM treatment, eWATs also secreted inflammatory adipokines related to the metastatic ability of cancer, muscle atrophy, and vascularization (NGAL, CD54, IGFBP-2, etc). Our work demonstrated that the eWAT is a robust model for studying cachectic fat loss and the accompanying remodeling of adipose tissue. It is therefore a useful tool for future research exploring CAC physiologies and developing potential therapies.

Excessive fat expenditure in cachexia is associated with dysregulated circadian rhythm: a review

Cachexia is a progressive metabolic disorder characterized by the excessive depletion of adipose tissue. This hypermetabolic condition has catastrophic impacts on the survival and quality of life for patients suffering from critical illness. However, efficient therapies to prevent adipose expenditure have not been discovered. It has been established that the circadian clock plays an important role in modulating fat metabolic processes. Recently, an increasing number of studies had provided evidence showing that disrupted circadian rhythm leads to insulin resistance and obesity; however, studies analyzing the relationship between circadian misalignment and adipose tissue expenditure in cachexia are scarce. In the present review, we cover the involvement of the circadian clocks in the regulation of adipogenesis, lipid metabolism and thermogenesis as well as inflammation in white and brown adipose tissue. According to the present review, we conclude that circadian clock disruption is associated with lipid metabolism imbalance and elevated adipose tissue inflammation. Moreover, under cachexia conditions, lipid synthesis and storage processes lost rhythm and decreased, while lipolysis and thermogenesis activities remained high for 24 h. Therefore, disordered circadian clock may be responsible for fat expenditure in cachexia by adversely influencing lipid synthesis/ storage/lipolysis/utilization. Further study needs to be performed to explore the direct interaction between circadian clock and fat expenditure in cachexia, it will likely provide potential efficient drugs for the treatment of fat expenditure in cachexia.

Concurrent Chemoradiotherapy Induces Body Composition Changes in Locally Advanced Head and Neck Squamous Cell Carcinoma: Comparison between Oral Cavity and Non-Oral Cavity Cancer

Few prospective cohort trials have evaluated the difference in treatment-interval total body composition (TBC) changes assessed by dual-energy X-ray absorptiometry (DXA) between two patient subgroups with locally advanced head and neck squamous cell carcinoma (LAHNSCC) receiving concurrent chemoradiotherapy (CCRT): oral cavity cancer with adjuvant CCRT (OCC) and non-oral cavity with primary CCRT (NOCC). This study prospectively recruited patients with LAHNSCC. Clinicopathological variables, blood nutritional/inflammatory markers, CCRT-related factors, and TBC data assessed by DXA before and after treatment were collected. Multivariate linear regression analysis identified the factors associated with treatment-interval changes in body composition parameters, including lean body mass (LBM), total fat mass (TFM), and bone mineral content (BMC). A total of 127 patients (OCC (n = 69) and NOCC (n = 58)) were eligible. Body composition parameters were progressively lost during CCRT in both subgroups. Extremities lost more muscle mass than the trunk for LBM, whereas the trunk lost more fat mass than the extremities for TFM. BMC loss preferentially occurred in the trunk region. Different factors were independently correlated with the interval changes of each body composition parameter for both OCC and NOCC subgroups, particularly mean daily calorie intake for LBM and TFM loss, and total lymphocyte count for BMC loss. In conclusion, treatment-interval TBC changes and related contributing factors differ between the OCC and NOCC subgroups.

Updates on the pathogenesis of advanced lung cancer-induced cachexia

Advanced lung cancer is becoming a chronic disease threatening human life and health. Cachexia has been recognized as the most common problem associated with advanced lung cancer. Lung cancer‐induced cachexia seriously affects patients’ quality of life. The present article summarizes the pathogenesis of advanced lung cancer‐induced cachexia from three aspects: anorexia, cytokines, and energy and metabolic abnormalities. In addition, the present article proposes corresponding nursing measures based on cachexia pathogenesis to improve the quality of life and survival rate of cachectic patients with advanced lung cancer by combining continuously advancing treatment regimens and effective nursing. The present article also provides references for healthcare professionals when administering related treatments and nursing care.

Neuroblastoma causes alterations of the intestinal microbiome, gut hormones, inflammatory cytokines, and bile acid composition

OBJECTIVE

To assess the effect of neuroblastoma (NB) on the intestinal microbiome, metabolism, and inflammatory parameters in a murine model.

MATERIALS AND METHODS

Athymic Hsd:Fox1nu mice received subperitoneal implantation of human NB cells (MHH-NB11) (tumor group, TG) or culture medium (sham group). Following 10 weeks of tumor growth, all animals were sacrificed to collect total white adipose tissue (WAT). Luminex assays were performed for gut hormone and inflammation marker analysis. Bile acids were measured by high-performance liquid chromatography-mass spectrometry in feces and serum. The microbiome of the ileal content was determined by 16S rDNA next-generation sequencing.

RESULTS

At 10 weeks, tumors masses in the TG reached a mean weight of 1.10 g (interquartile range 3.45 g) associated with a significant reduction in WAT. Furthermore, in the TG, there was a marked reduction in leptin and an increase in glucagon-like peptide 1 serum levels. Moreover, the TG mice displayed a pro-inflammatory profile, with significant increases in monocyte chemotactic protein 1, tumor necrosis factor alpha, and interleukin-10. Lithocholic acid, deoxycholic acid, and ursodeoxycholic acid were significantly decreased in the stool of TG mice. Significant alterations of the intestinal microbiome were found in the ileal contents of the TG.

CONCLUSIONS

The present study provides a first glimpse that human NB in a murine model induces tumor cachexia associated with alterations in metabolic and inflammatory parameters, as well as changes in the intestinal microbiota. Since the intestinal microbiome is known to contribute to the host's ability to harvest energy, a favorable modulation of the intestinal microbiome in tumor patients could potentially represent a novel therapeutic target to prevent tumor-associated cachexia.

Adipose tissue lipolysis and energy metabolism in early cancer cachexia in mice

Cancer cachexia is a progressive metabolic disorder that results in depletion of adipose tissue and skeletal muscle. A growing body of literature suggests that maintaining adipose tissue mass in cachexia may improve quality-of-life and survival outcomes. Studies of lipid metabolism in cachexia, however, have generally focused on later stages of the disorder when severe loss of adipose tissue has already occurred. Here, we investigated lipid metabolism in adipose, liver and muscle tissues during early stage cachexia - before severe fat loss - in the colon-26 murine model of cachexia. White adipose tissue mass in cachectic mice was moderately reduced (34-42%) and weight loss was less than 10% of initial body weight in this study of early cachexia. In white adipose depots of cachectic mice, we found evidence of enhanced protein kinase A - activated lipolysis which coincided with elevated total energy expenditure and increased expression of markers of brown (but not white) adipose tissue thermogenesis and the acute phase response. Total lipids in liver and muscle were unchanged in early cachexia while markers of fatty oxidation were increased. Many of these initial metabolic responses contrast with reports of lipid metabolism in later stages of cachexia. Our observations suggest intervention studies to preserve fat mass in cachexia should be tailored to the stage of cachexia. Our observations also highlight a need for studies that delineate the contribution of cachexia stage and animal model to altered lipid metabolism in cancer cachexia and identify those that most closely mimic the human condition.

Serum Levels of the Adipokine Zinc- α 2-glycoprotein Are Decreased in Patients with Hypertension

Objective. Zinc-α2-glycoprotein (ZAG) has recently been proposed as a new adipokine involved in body weight regulation. The purpose of this study is to investigate serum levels of ZAG in patients with hypertension and its association with related characteristics. Methods. 32 hypertension patients and 42 normal controls were recruited and the relationship between serum ZAG, total and high molecular weight (HMW) adiponectin, and tumor necrosis factor-α (TNFα) determined by enzyme-linked immunosorbent assay (ELISA) and metabolic-related parameters was investigated. Results. Serum ZAG concentrations were significantly lowered in patients with hypertension compared with healthy controls (61.4 ± 32 versus 78.3 ± 42 μg/mL, P < 0.05). The further statistical analysis demonstrated that serum ZAG levels were negatively correlated with waist-to-hip ratio (WHR) (r = −0.241, P < 0.05) and alanine aminotransferase (ALT) (r = −0.243, P < 0.05). Additionally, serum HMW adiponectin significantly decreased, while TNFα greatly increased in hypertension patients as compared with healthy controls (2.32 ± 0.41 versus 5.24 ± 1.02 μg/mL, 3.30 ± 1.56 versus 2.34 ± 0.99 pg/mL, P < 0.05). Conclusions. Serum ZAG levels are significantly lowered in hypertension patients and negatively correlated with obesity-related item WHR, suggesting ZAG is a factor associated with hypertension.

Inhibition of preadipocyte differentiation and adipogenesis by zinc-α2-glycoprotein treatment in 3T3-L1 cells

Aims/Introduction

Zinc‐α2‐glycoprotein (ZAG) is associated with the loss of adipose tissue in cancer cachexia, and has recently been proposed to be a candidate factor in the regulation of bodyweight. The aim of the study was to investigate the effects of ZAG on the proliferation and differentiation of 3T3‐L1 preadipocytes.

Materials and Methods

3‐(4,5‐Dimethylthiazol‐2‐yl) 2,5‐diphenyl tetrazolium bromide (MTT) spectrophotometry, Oil Red O staining, intracellular triglyceride assays, real‐time quantitative reverse transcription polymerase chain reaction and transient transfection methods were used to explore the action of ZAG.

Results

Ectopic ZAG expression significantly stimulates 3T3‐L1 cells proliferation in a dose‐ and time‐dependent manner. The maximum influence of ZAG on proliferation was 1.43‐fold higher than what was observed in control cells. This effect was observed 144 h after transfection with 0.16 μg of murine ZAG (mZAG) plasmid (P < 0.001). The intracellular lipids content in mZAG over‐expressing cells were decreased as much as 37% when compared with the control cells after differentiation (P < 0.05, P < 0.01). The messenger ribonucleic acid levels of peroxisome proliferators‐activated receptor‐γ (PPARγ), CCAAT enhancer‐binding protein‐α (C/EBPα) and the critical lipogenic gene, fatty acid synthase (FAS), are also downregulated by up to 50% in fully differentiated ZAG‐treated adipocytes. ZAG suppresses FAS messenger ribonucleic acid expression by reducing FAS promoter activity.

Conclusions

Zinc‐α2‐glycoprotein stimulates the proliferation and inhibits the differentiation of 3T3‐L1 murine preadipocytes. The inhibitory action of ZAG on cell differentiation might be a result of the attenuation of the expression of PPARγ, C/EBPα and the lipogenic‐specific enzyme FAS by reducing FAS promoter activity.

The effect of exercise on IL-6-induced cachexia in the Apc ( Min/+) mouse

BACKGROUND

Cachexia involves unintentional body weight loss including diminished muscle and adipose tissue mass and is associated with an underlying disease. Systemic overexpression of IL-6 accelerates cachexia in the Apc(Min/+) mouse, but does not induce wasting in control C57BL/6 mice. With many chronic diseases, chronic inflammation and metabolic dysfunction can be improved with moderate exercise. A direct effect of regular moderate exercise on the prevention of IL-6-induced cachexia in the Apc(Min/+) mouse has not been investigated. The purpose of this study was to assess the effects of exercise on the development of cachexia in the Apc(Min/+) mouse.

METHODS

Mice were randomly assigned to moderate treadmill exercise (18 m/min, 1 h, 6 days/week, 5% grade) or cage control (CC) groups from 6 to 14 weeks of age. At 12 weeks of age, mice were electroporated with either IL-6-containing or control plasmid into the quadriceps muscle. Mice were killed after 2 weeks of systemic IL-6 overexpression or control treatment.

RESULTS

IL-6 overexpression induced an 8% loss in body weight in CC mice, which was significantly attenuated by exercise. IL-6 overexpression in CC mice increased fasting insulin and triglyceride levels, which were normalized by exercise, and associated with increased oxidative capacity, an induction of AKT signaling, and a repression of AMPK signaling in muscle. These exercise-induced changes occurred despite elevated inflammatory signaling in skeletal muscle.

CONCLUSION

We conclude that moderate-intensity exercise can attenuate IL-6-dependent cachexia in Apc(Min/+) mice, independent of changes in IL-6 concentration and muscle inflammatory signaling. The exercise effect was associated with improved insulin sensitivity and improved energy status in the muscle.

Adipose tissue inflammation and cancer cachexia: possible role of nuclear transcription factors

Cancer cachexia is a multifaceted syndrome whose aetiology is extremely complex and is directly related to poor patient prognosis and survival. Changes in lipid metabolism in cancer cachexia result in marked reduction of total fat mass, increased lipolysis, total oxidation of fatty acids, hyperlipidaemia, hypertriglyceridaemia, and hypercholesterolaemia. These changes are believed to be induced by inflammatory mediators, such as tumour necrosis factor-α (TNF-α) and other factors. Attention has recently been drawn to the current theory that cachexia is a chronic inflammatory state, mainly caused by the host's reaction to the tumour. Changes in expression of numerous inflammatory mediators, notably in white adipose tissue (WAT), may trigger several changes in WAT homeostasis. The inhibition of adipocyte differentiation by PPARγ is paralleled by the appearance of smaller adipocytes, which may partially account for the inhibitory effect of PPARγ on inflammatory gene expression. Furthermore, inflammatory modulation and/or inhibition seems to be dependent on the IKK/NF-κB pathway, suggesting that a possible interaction between NF-κB and PPARγ is required to modulate WAT inflammation induced by cancer cachexia. In this article, current literature on the possible mechanisms of NF-κB and PPARγ regulation of WAT cells during cancer cachexia are discussed. This review aims to assess the role of a possible interaction between NF-κB and PPARγ in the setting of cancer cachexia as well as its significant role as a potential modulator of chronic inflammation that could be explored therapeutically.