Diminished visceral adipose tissue in cancer cachexia

Insulin resistance and body composition in cancer patients

Cancer cachexia, weight loss with altered body composition, is a multifactorial syndrome propagated by symptoms that impair caloric intake, tumor byproducts, chronic inflammation, altered metabolism, and hormonal abnormalities. Cachexia is associated with reduced performance status, decreased tolerance to chemotherapy, and increased mortality in cancer patients. Insulin resistance as a consequence of tumor byproducts, chronic inflammation, and endocrine dysfunction has been associated with weight loss in cancer patients. Insulin resistance in cancer patients is characterized by increased hepatic glucose production and gluconeogenesis, and unlike type 2 diabetes, normal fasting glucose with high, normal or low levels of insulin. Cancer cachexia results in altered body composition with the loss of lean muscle mass with or without the loss of adipose tissue. Alteration in visceral adiposity, accumulation of intramuscular adipose tissue, and secretion of adipocytokines from adipose cells may play a role in promoting the metabolic derangements associated with cachexia including a proinflammatory environment and insulin resistance. Increased production of ghrelin, testosterone deficiency, and low vitamin D levels may also contribute to altered metabolism of glucose. Cancer cachexia cannot be easily reversed by standard nutritional interventions and identifying and treating cachexia at the earliest stage of development is advocated. Experts advocate for multimodal therapy to address symptoms that impact caloric intake, reduce chronic inflammation, and treat metabolic and endocrine derangements, which propagate the loss of weight. Treatment of insulin resistance may be a critical component of multimodal therapy for cancer cachexia and more research is needed.

Characterization of patients with advanced pancreatic cancer and high serum interleukin-6 levels

OBJECTIVES

High serum level of interleukin 6 (IL-6) is associated with high degree of tumor progression and systemic weakness. Anti-IL-6 therapy possibly improves the deterioration of clinical characteristics in patients with high IL-6 level. However, IL-6-related factors in patients with treatment-naive advanced pancreatic cancer (PC) have not been established. The goal of this study was to identify IL-6-related factors in patients with advanced PC who were scheduled to undergo first-line chemotherapy.

METHODS

Patients with treatment-naive advanced PC were eligible for inclusion in this study. Patients who did not receive first-line chemotherapy were excluded. Serum IL-6 levels and clinical parameters were prospectively recorded. Analyses were performed to identify risk factors for high IL-6 levels.

RESULTS

Eighty patients were analyzed. IL-6-related factors were advanced age (P < 0.01), the presence of liver metastasis (P < 0.01), the large volume of liver metastasis (P < 0.01), severe fatigue (P = 0.02), high carcinoembryonic antigen levels (P = 0.02), anemia (P < 0.01), and high C-reactive protein levels (P = 0.02) in multivariate analyses. Decreased skeletal muscle mass tended to be associated with high IL-6 levels.

CONCLUSIONS

High serum IL-6 was related to advanced age, the presence of hepatic metastasis, large tumor burden in liver, severe fatigue, high carcinoembryonic antigen, high C-reactive protein, and anemia in patients with treatment-naive advanced PC.

Prognostic value of components of body composition in patients treated with targeted therapy for advanced renal cell carcinoma: a retrospective case series

Background

To evaluate the association between various components of body composition and overall survival of patients treated with targeted therapies for advanced renal cell carcinoma.

Methods

This retrospective study included 124 Chinese patients with advanced renal cell carcinoma who had been treated with targeted therapy from 2008 to 2012 at Fudan University Cancer Center. The L3 plane from a computed tomography scan was analyzed. Area and density were recorded as quantitative and quality measures. Univariate and multivariate Cox proportion hazard regression models were constructed to calculate the crude and adjusted hazard ratio (HR) of various components of body composition for overall survival. X-tile software was used to search for optimal cutoffs for male and female patients and the concordance index evaluated incremental changes in prognostication.

Results

After adjusting for age, sex and Heng risk stratification, only visceral adipose tissue index (HR 0.981, p = 0.002) and subcutaneous adipose tissue index (HR 0.987, p = 0.048) were independently associated with overall survival. Visceral adipose tissue remained a significant prognostic factor (HR 0.997, p = 0.005) when the influence of body mass index was included. Using defined cutoffs, patients with low VAT had double the death rate (p = 0.007). Visceral adipose tissue also added significant benefit to Heng risk stratification. Further exploratory analysis revealed that visceral adipose tissue may be an indicator of nutritional status in patients with advanced renal cell carcinoma.

Conclusion

Radiologic measurement of VAT is an independent prognostic factor for Asian patients treated with targeted therapy for advanced renal cell carcinoma.

Evidence and mechanisms of fat depletion in cancer

The majority of cancer patients experience wasting characterized by muscle loss with or without fat loss. In human and animal models of cancer, body composition assessment and morphological analysis reveals adipose atrophy and presence of smaller adipocytes. Fat loss is associated with reduced quality of life in cancer patients and shorter survival independent of body mass index. Fat loss occurs in both visceral and subcutaneous depots; however, the pattern of loss has been incompletely characterized. Increased lipolysis and fat oxidation, decreased lipogenesis, impaired lipid depositionand adipogenesis, as well as browning of white adipose tissue may underlie adipose atrophy in cancer. Inflammatory cytokines such as interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and interleukin-1 beta (IL-1β) produced by the tumor or adipose tissue may also contribute to adipose depletion. Identifying the mechanisms and time course of fat mass changes in cancer may help identify individuals at risk of adipose depletion and define interventions to circumvent wasting. This review outlines current knowledge of fat mass in cancer and illustrates the need for further studies to assess alterations in visceral and subcutaneous adipose depots and possible mechanisms for loss of fat during cancer progression.

Relationships among body mass index, longitudinal body composition alterations, and survival in patients with locally advanced pancreatic cancer receiving chemoradiation: a pilot study

CONTEXT

In pancreatic cancer, the presence of obesity or weight loss is associated with higher mortality.

OBJECTIVES

To explore the relationships among body mass index, longitudinal body composition alterations, and clinical outcomes in pancreatic cancer patients.

METHODS

Records of 41 patients with inoperable locally advanced pancreatic cancer who participated in a prospective chemoradiation study were reviewed. Body composition was analyzed from two sets of computed tomography images obtained before and after radiation treatment (median interval 104 days).

RESULTS

Median age was 59 years and 56% of patients were female. Twenty-four (59%) patients were either overweight (22%) or obese (37%). Sarcopenia was present in 26 (63%) patients. At follow-up, weight loss was experienced by 33 (81%) patients. The median losses (%) before and after treatment were weight 5% (P<0.001), skeletal muscle (SKM) 4% (P=0.003), visceral adipose tissue (VAT) 13% (P<0.001), and subcutaneous adipose tissue 11% (P=0.002). SKM loss positively correlated with age (P=0.03), baseline body mass index (P<0.001), and VAT (P=0.04) index. Obese patients experienced higher losses in weight (P=0.009), SKM (P=0.02), and VAT (P=0.02). Median survival was 12 months. In univariate analysis, age, baseline obesity, sarcopenic obesity, and losses (%) in weight, SKM, and VAT were associated with worse survival. In multivariate analysis, only age (hazard ratio=1.033, P=0.04) and higher VAT loss (hazard ratio=2.6 and P=0.03) remained significant.

CONCLUSION

Our preliminary findings suggest that obese patients experience higher losses in weight, SKM, and VAT, which may contribute to poorer survival in these patients.

Altered expression of genes in adipose tissues associated with reduced fat mass in patients with pancreatic cancer

Loss of adipose tissue in patients with pancreatic cancer may involve altered gene expression. Peri-operative mRNA levels of 44 genes were analysed by RT-PCR in intra-abdominal (IAAT) and subcutaneous adipose tissue (SCAT) sampled from pancreatic ductal adenocarcinoma (PDAC) patients undergoing tumour resection (n = 20), and control patients without cancer (n = 11). Peri- and post-operative IAAT and SCAT masses were measured by computerized tomography. PDAC patients displayed 2.6- and 1.7-fold higher Zn-α2-glycoprotein (AZGP1) mRNA levels than controls in IAAT and SCAT, respectively (P < 0.01), but expression was not correlated with post-operative changes in fat masses. IAAT mass changes correlated with genes in lipid metabolism, inflammation and apoptosis: e.g. stearoyl-Coenzyme A desaturase 1 (SCD), tumour necrosis factor (TNF) and chemokine (C-C motif) ligand 2 (CCL2; MCP-1). Patients with PDAC displayed increased AZGP1 mRNA levels in both IAAT and SCAT, but expression of other genes may predict IAAT loss.

New insights into adipose tissue atrophy in cancer cachexia

Profound loss of adipose and other tissues is a hallmark of cancer cachexia, a debilitating condition associated with increased morbidity and mortality. Fat loss cannot be attributable to reduced appetite alone as it precedes the onset of anorexia and is much more severe in experimental models of cachexia than in food restriction. Morphological examination has shown marked remodelling of adipose tissue in cancer cachexia. It is characterised by the tissue containing shrunken adipocytes with a major reduction in cell size and increased fibrosis in the tissue matrix. The ultrastructure of 'slimmed' adipocytes has revealed severe delipidation and modifications in cell membrane conformation. Although the molecular mechanisms remain to be established, evidence suggests that altered adipocyte metabolism may lead to adipose atrophy in cancer cachexia. Increased lipolysis appears to be a key factor underlying fat loss, while inhibition of adipocyte development and lipid deposition may also contribute. Both tumour and host-derived factors are implicated in adipose atrophy. Zinc-alpha2-glycoprotein (ZAG), which is overexpressed by certain malignant tumours, has been identified as a novel adipokine. ZAG transcripts and protein expression in adipose tissue are up regulated in cancer cachexia but reduced with adipose tissue expansion in obesity. Studies in vitro demonstrate that recombinant ZAG stimulates lipolysis. ZAG may therefore act locally, as well as systemically, to promote lipid mobilisation in cancer cachexia. Further elucidation of ZAG function in adipose tissue may lead to novel targets for preventing adipose atrophy in malignancy.

Regulation of adipose tissue metabolism in cancer cachexia

PURPOSE OF REVIEW

Body-fat depletion is a hallmark of cancer cachexia, a complex clinical syndrome associated with increased morbidity and mortality. Understanding the fat-loss disorder in cachexia is essential for the development of better treatments for the syndrome. This review presents recent studies focusing on the mechanisms of adipose atrophy in cancer cachexia, particularly the potential mediators.

RECENT FINDINGS

Fat loss cannot be explained by poor appetite alone, and may also result from altered lipid metabolism in adipocytes. Increased lipolysis appears to be a key factor underlying fat loss in cancer cachexia though decreases in lipid deposition and adipocyte development may also contribute. Both tumour and host-derived factors are implicated in adipose tissue atrophy. Tumour necrosis factor-alpha has been associated with increased lipolysis in adipocytes. The novel adipokine zinc-alpha2-glycoprotein may function locally, as well as systemically, to promote lipid mobilization and utilization in cancer cachexia.

SUMMARY

Clarifying the role of cachexia mediators in adipose tissue atrophy will add to our understanding of adipocyte metabolism in wasting disease. Elucidating their mode of action may lead to novel therapeutic targets for counteracting the cachexia syndrome.

Fat distribution in men with HIV infection

OBJECTIVE

Both peripheral fat loss and central fat gain have been reported in HIV infection. Which changes are specific to HIV were determined by comparison with control subjects and the associations among different adipose tissue depots were determined.

METHODS

Cross-sectional analysis of HIV-positive and control men from the study of Fat Redistribution and Metabolic Change in HIV Infection. Lipoatrophy or lipohypertrophy was defined as concordance between participant report of change and examination. Regional adipose tissue volume was measured by magnetic resonance imaging (MRI).

RESULTS

HIV-positive men reported more fat loss than controls in all peripheral and most central depots. Peripheral lipoatrophy was more frequent in HIV-positive men than in controls (38.3% vs. 4.6%, P < 0.001), whereas central lipohypertrophy was less frequent (40.2% vs. 55.9%, P = 0.001). Among HIV-positive men, the presence of central lipohypertrophy was not positively associated with peripheral lipoatrophy (odds ratio = 0.71, CI: 0.47 to 1.06, P = 0.10). On MRI, HIV-positive men with clinical peripheral lipoatrophy had less subcutaneous adipose tissue (SAT) in peripheral and central sites and less visceral adipose tissue (VAT) than HIV-positive men without peripheral lipoatrophy. HIV-positive men both with and without lipoatrophy had less SAT than controls, with legs and lower trunk more affected than upper trunk. Use of the antiretroviral drugs stavudine or indinavir was associated with less leg SAT but did not appear to be associated with more VAT; nevirapine use was associated with less VAT.

CONCLUSION

Both peripheral and central subcutaneous lipoatrophy was found in HIV infection. Lipoatrophy in HIV-positive men is not associated with reciprocally increased VAT.