Hypoleptinemia in gastric cancer patients: relation to body fat mass, insulin, and growth hormone

Biomarkers of cancer cachexia

Cachexia is a complex multifactorial syndrome, characterized by loss of skeletal muscle and fat mass, which affects the majority of advanced cancer patients and is associated with poor prognosis. Interestingly, reversing muscle loss in animal models of cancer cachexia leads to prolong survival. Therefore, detecting cachexia and maintaining muscle mass represent a major goal in the care of cancer patients. However, early diagnosis of cancer cachexia is currently limited for several reasons. Indeed, cachexia development is variable according to tumor and host characteristics. In addition, safe, accessible and non-invasive tools to detect skeletal muscle atrophy are desperately lacking in clinical practice. Finally, the precise molecular mechanisms and the key players involved in cancer cachexia remain poorly characterized. The need for an early diagnosis of cancer cachexia supports therefore the quest for a biomarker that might reflect skeletal muscle atrophy process. Current research offers different promising ways to identify such a biomarker. Initially, the quest for a biomarker of cancer cachexia has mostly focused on mediators of muscle atrophy, produced by both tumor and host, in an attempt to define new therapeutic approaches. In another hand, molecules released by the muscle into the circulation during the atrophy process have been also considered as potential biomarkers. More recently, several "omics" studies are emerging to identify new muscular or circulating markers of cancer cachexia. Some genetic markers could also contribute to identify patients more susceptible to develop cachexia. This article reviews our current knowledge regarding potential biomarkers of cancer cachexia.

Potential Biomarkers of Fat Loss as a Feature of Cancer Cachexia

Fat loss is associated with shorter survival and reduced quality of life in cancer patients. Effective intervention for fat loss in cachexia requires identification of the condition using prognostic biomarkers for early detection and prevention of further depletion. No biomarkers of fat mass alterations have been defined for application to the neoplastic state. Several inflammatory cytokines have been implicated in mediating fat loss associated with cachexia; however, plasma levels may not relate to adipose atrophy. Zinc-α2-glycoprotein may be a local catabolic mediator within adipose tissue rather than serving as a plasma biomarker of fat loss. Plasma glycerol and leptin associate with adipose tissue atrophy and mass, respectively; however, no study has evaluated their potential as a prognostic biomarker of cachexia-associated fat loss. This review confirms the need for further studies to identify valid prognostic biomarkers to identify loss of fat based on changes in plasma levels of biomarkers.

Serum leptin levels in gastric cancer patients and the relationship with insulin resistance

INTRODUCTION

Serum leptin levels have been examined in various cancers, with conflicting results. However, there is limited information regarding serum leptin levels and insulin resistance in gastric cancer patients. Therefore, we aimed to investigate serum leptin levels, performance status, insulin levels and insulin resistance in patients with gastric cancer. In addition, we examined the relationship between these measurements and leptin levels.

MATERIAL AND METHODS

Thirty-nine patients with gastric cancer and 30 control subjects were enrolled in the study. Serum leptin, total protein, albumin, growth hormone, insulin and glucose levels were measured. The homeostasis model assessment (HOMA) was used to assess insulin resistance.

RESULTS

Serum levels of insulin, glucose and growth hormone and insulin resistance were significantly lower in gastric cancer patients than controls (p < 0.05 for all). In the Pearson correlation analysis, insulin resistance was found to be significantly correlated with serum leptin levels in gastric cancer patients (r = 0.320, p = 0.047). We observed a significant negative correlation between performance status and insulin resistance in patients with cachexia (r = -0.512, p = 0.030), while no association was found in non-cachectic patients.

CONCLUSIONS

We concluded that serum leptin levels are significantly lower in gastric cancer patients. In addition, gastric cancer patients have decreases in insulin levels, insulin resistance and growth hormone levels. This study found a positive association between serum leptin levels and insulin resistance. Moreover, there is a negative association between serum leptin levels and growth hormone levels. Thus, low insulin and growth hormone levels may suppress the production of leptin in gastric cancer patients.

Plasma MIC-1 correlates with systemic inflammation but is not an independent determinant of nutritional status or survival in oesophago-gastric cancer

Background:

Macrophage inhibitory cytokine-1(MIC-1) is a potential modulator of systemic inflammation and nutritional depletion, both of which are adverse prognostic factors in oesophago-gastric cancer (OGC).

Methods:

Plasma MIC-1, systemic inflammation (defined as plasma C-reactive protein (CRP) of ⩾10 mg l^–1 or modified Glasgow prognostic score (mGPS) of ⩾1), and nutritional status were assessed in newly diagnosed OGC patients (n=293). Healthy volunteers (n=35) served as controls.

Results:

MIC-1 was elevated in patients (median=1371 pg ml^–1; range 141–39 053) when compared with controls (median=377 pg ml^–1; range 141–3786; P<0.001). Patients with gastric tumours (median=1592 pg ml^–1; range 141–12 643) showed higher MIC-1 concentrations than patients with junctional (median=1337 pg ml^–1; range 383–39 053) and oesophageal tumours (median=1180 pg ml^–1; range 258–31 184; P=0.015). Patients showed a median weight loss of 6.4% (range 0.0–33.4%), and 42% of patients had an mGPS of ⩾1 or plasma CRP of ⩾10 mg l^–1 (median=9 mg l^–1; range 1–200). MIC-1 correlated positively with disease stage (r²=0.217; P<0.001), age (r²=0.332; P<0.001), CRP (r²=0.314; P<0.001), and mGPS (r²=0.336; P<0.001), and negatively with Karnofsky Performance Score (r²=−0.269; P<0.001). However, although MIC-1 correlated weakly with dietary intake (r²=0.157; P=0.031), it did not correlate with weight loss, BMI, or anthropometry. Patients with MIC-1 levels in the upper quartile showed reduced survival (median=204 days; 95% CI 157–251) when compared with patients with MIC-1 levels in the lower three quartiles (median=316 days; 95% CI 259–373; P=0.036), but MIC-1 was not an independent prognostic indicator.

Conclusions:

There is no independent link between plasma MIC-1 levels and depleted nutritional status or survival in OGC.

Insulin treatment in cancer cachexia: effects on survival, metabolism, and physical functioning

PURPOSE

The present study was designed to evaluate whether daily insulin treatment for weight-losing cancer patients attenuates the progression of cancer cachexia and improves metabolism and physical functioning in palliative care.

EXPERIMENTAL DESIGN

One hundred and thirty-eight unselected patients with mainly advanced gastrointestinal malignancy were randomized to receive insulin (0.11 +/- 0.05 units/kg/d) plus best available palliative support [anti-inflammatory treatment (indomethacin), prevention of anemia (recombinant erythropoietin), and specialized nutritional care (oral supplements + home parenteral nutrition)] according to individual needs. Control patients received the best available palliative support according to the same principles. Health-related quality of life, food intake, resting energy expenditure, body composition, exercise capacity, metabolic efficiency during exercise, and spontaneous daily physical activity as well as blood tests were evaluated during follow-up (30-824 days) according to intention to treat.

RESULTS

Patient characteristics at randomizations were almost identical in study and control groups. Insulin treatment for 193 +/- 139 days (mean +/- SD) significantly stimulated carbohydrate intake, decreased serum-free fatty acids, increased whole body fat, particularly in trunk and leg compartments, whereas fat-free lean tissue mass was unaffected. Insulin treatment improved metabolic efficiency during exercise, but did not increase maximum exercise capacity and spontaneous physical activity. Tumor markers in blood (CEA, CA-125, CA 19-9) did not indicate the stimulation of tumor growth by insulin; a conclusion also supported by improved survival of insulin-treated patients (P<0.03).

CONCLUSION

Insulin is a significant metabolic treatment in multimodal palliation of weight-losing cancer patients.

Circulating ghrelin in patients with gastric or colorectal cancer

The purpose of this study was to investigate the pathophysiologic change of ghrelin in gastric and colorectal cancer patients, especially in those with cachexia. Fifty-eight gastric cancer patients, 20 colorectal cancer patients, and 24 healthy control individuals were included in this study. Thirty-one patients were defined as cachectic, based on the percentage of weight loss versus the previous normal weight. The remaining 47 patients were defined as noncachectic. Peripheral hormones, including ghrelin, insulin, leptin, growth hormone, glucagon, and cortisol, and body composition parameters were measured. Plasma ghrelin levels did not increase significantly in cachectic gastric (p = 0.352) or colorectal (p = 0.871) cancer patients as compared with controls and were not correlated with nutrition status and other hormones. The location of gastric cancer (proximal vs. distal) had no influence on ghrelin levels (p = 0.966). These findings suggest that gastric and colorectal cancers may have their special effects on the production of ghrelin. Gastric or colorectal cancer cachexia may be partly due to the lack of increase in ghrelin, which makes exogenous ghrelin therapy feasible in this setting.

Cancer-associated malnutrition

Malnutrition is a common problem among patients with cancer, affecting up to 85% of patients with certain cancers (e.g. pancreas). In severe cases, malnutrition can progress to cachexia, a specific form of malnutrition characterised by loss of lean body mass, muscle wasting, and impaired immune, physical and mental function. Cancer cachexia is also associated with poor response to therapy, increased susceptibility to treatment-related adverse events, as well as poor outcome and quality of life. Cancer cachexia is a complex, multifactorial syndrome, which is thought to result from the actions of both host- and tumour-derived factors, including cytokines involved in a systemic inflammatory response to the tumour. Early intervention with nutritional supplementation has been shown to halt malnutrition, and may improve outcome in some patients. However, increasing nutritional intake is insufficient to prevent the development of cachexia, reflecting the complex pathogenesis of this condition. Nutritional supplements containing anti-inflammatory agents, for example the polyunsaturated fatty acid (PUFA) eicosapentanoic acid (EPA), have been shown to be more beneficial to malnourished patients than nutritional supplementation alone. EPA has been shown to interfere with multiple mechanisms implicated in the pathogenesis of cancer cachexia, and in clinical studies, has been associated with reversal of cachexia and improved survival.