Serum tumor necrosis factor does not correlate with changes in muscle volume in children with malignancies

Nutritional status and cytokine concentration during chemotherapy in Mexican children: A longitudinal analysis

OBJECTIVE

The aim of this study was to assess whether the nutritional status of children with cancer is influenced by variations in cytokine concentrations observed during chemotherapy. We also evaluated whether this relationship could be modified by nutritional status at diagnosis and type of cancer.

METHODS

Mexican children with lymphoma or solid tumors were evaluated at diagnosis and at 2- and 6-mo follow-up visits. Blood samples were obtained to determine serum prealbumin, tumor necrosis factor (TNF)-α, interleukin (IL)-6, leptin concentrations, and hemoglobin. Children were classified as undernourished (UN) or well nourished (WN), according to prealbumin concentration. The influence of each cytokine on prealbumin concentration was analyzed by time-series regression model.

RESULTS

Fifty patients (ages 2-17 y) were enrolled. There were 17 children with lymphomas and 33 with solid tumors. At baseline, 56% were UN and 26% presented anemia; the frequencies of UN children were higher for those with lymphoma than for those with a solid tumor (P = 0.003). By nutritional status, UN children presented lower leptin (P = 0.002) but higher IL-6 concentrations (P = 0.009) than the WN group. Children with lymphoma presented lower prealbumin (P = 0.003), but higher TNF-α (P = 0.001) and IL-6 (P = 0.011) concentrations than those with solid tumors. At follow-up, the concentration of prealbumin increased and IL-6 decreased in children with lymphoma. Multivariate analysis demonstrated that decreases in prealbumin concentration at the end of follow-up were associated with increases in IL-6 and TNF-α concentration during chemotherapy.

CONCLUSIONS

These results suggest that the cytokine responses during chemotherapy are related to nutritional status at the end of 6 mo of treatment regardless of the initial nutritional status and the type of cancer.

Pathophysiology of cancer cachexia

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

Serum levels of tumour necrosis factor alpha and other cytokines do not correlate with weight loss and anorexia in cancer patients

Cancer anorexia-cachexia syndrome (CACS), which is characterized by progressive weight loss (WL) and anorexia (A), is present in 50% of advanced cancer patients and in 80% of terminally ill cancer patients. One of the most controversial aspects of CACS is its oetiopathogenesis; experimental studies have identified certain cytokines [Tumour necrosis factor alpha (TNF-alpha), interleukin 1 (IL-1), interleukin 6 (IL-6), and gamma interferon (gamma-IFN)] as possible co-factors in the onset of the syndrome. The aim of our study was to investigate the correlation between serum levels of circulating cytokines and severity of CACS. The following series of parameters was identified in 61 patients with advanced and terminal cancer: stage of disease; Karnofsky performance status (KPS) and clinical symptoms; biohumoral, anthropometric and immunological situation; level of circulating cytokines. All these parameters were evaluated for a possible link with WL/A. Our data do not show any significant correlation between circulating cytokines and WL/A. A direct correlation was identified between WL/A and nausea (P = 0.03 and P < 0.001, respectively) whereas inverse correlations were observed for both factors as regards arm circumference (P < 0.001 for both), wrist circumference (P < 0.001 for both), KPS (P < 0.001 and P = 0.003, respectively) and creatinine (P = 0.005 and P = 0.03, respectively). Other biochemical factors, such as haemoglobin, haematocrit, glycaemia, prealbumin, sodium and chlorine were also correlated with at least one of two clinical parameters in question. Unexpected results were seen in the increases in CD20 and CD4 and in the CD4/CD8 ratio. Serum levels of these cytokines do not, therefore, appear to be critical in the onset of CACS. On the contrary, our findings confirmed the clinico-laboratory picture that is characteristic of CACS. If we consider the possibility that CACS is provoked by an aspecific response of the host's defence mechanisms against prolonged neoplastic attack, the increase in CD4 (helper lymphocytes) could be linked to the persistent response.

Are cytokines possible mediators of cancer cachexia?

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

Tumor necrosis factor and cachexia: a current perspective

Anorexia, net proteolysis of skeletal muscle and consumption of body fat are hallmarks of the cachexia syndrome associated with chronic disease states. While inanition contributes to cachexia, this wasting diathesis has little in common with simple starvation. The cachexia syndrome is characterized by progressive weight loss and depletion of lean body mass in excess to that resulting from comparable caloric restriction. Accelerated mobilization and consumption of host protein stores from peripheral tissues occurs to support gluconeogenesis and acute phase protein synthesis [1, 2]. In contrast, simple starvation is associated with a relative sparing of lean tissue with the preferential consumption of fat. While the clinical manifestations of cachexia are readily apparent, identification of the specific mechanisms responsible for the development of cachexia remains an enigma. In recent years, interest has focused on the role that the immune system plays in the development of cachexia. Investigators initially hypothesized that the chronic production of two inflammatory cytokines, tumour necrosis factor alpha (TNF alpha) and/or interleukin-1 (IL-1), could explain the host non-specific responses resulting in cachexia [3-5]. Other pro-inflammatory cytokines, including interleukin-6 (IL-6) [6, 7] and interferon-gamma [8, 9], have been more recently proposed to be involved in this complex process. Although no consensus exists for the exclusive role of any one cytokine in the pathogenesis of cachexia, there is growing acceptance that the progression of cachexia results in part from the inappropriate release of one or more pro-inflammatory cytokines [10, 11]. In the present review, the current role of TNF alpha as a mediator of cachexia is examined.

Serum soluble interleukin-2 receptors and tumor necrosis factor-alpha in hematological malignancies of childhood

The levels of soluble interleukin-2 receptors (sIL-2R) and tumor necrosis factor (TNF) were determined in the serum of 61 children with hematological malignancy, including 20 patients with leukemia and 16 with lymphoma in active state of malignancy, and 20 patients with leukemia and 5 with lymphoma in complete remission. In addition, serum samples from 15 healthy children were used as controls. It was found that the mean serum levels of sIL-2R and TNF were significantly increased in active malignancy (207.0 +/- 17.1 pmol/L for sIL-2R; 209.7 +/- 35.0 pg/mL for TNF) compared to the remission status and normal controls (P < 0.001). No such difference was observed between leukemia and lymphoma groups. It was concluded that serum sIL-2R and TNF are of potential value in the diagnosis and follow up of patients with neoplastic diseases.