Background: Anorexia, cachexia, and insulin resistance are commonly seen in patients with cancer. Adipocyte-derived hormones or adipokines play a role in the regulation of appetite, body weight, and insulin sensitivity. However, their role in cancer-induced cachexia has not been well-established. The objective of this study was to determine the levels of adipokines and their relation to appetite, weight loss, insulin resistance, and other hormones in cancer cachexia.
Methods: We measured adiponectin, resistin, and leptin plasma levels in 21 men with cancer cachexia, 24 noncachectic cancer subjects, and 25 noncancer controls matched by age, sex, and pre-illness body weight. Body weight change, appetite scores, insulin resistance assessed by homeostasis model assessment, and other cytokines and hormones were also measured. Differences between groups were measured by analysis of covariance. Relations between variables were examined by linear regression analyses.
Results: Adiponectin levels were similarly elevated in cachectic and noncachectic cancer patients compared with noncancer controls. Leptin levels were significantly decreased in cancer cachexia and were directly associated with appetite and insulin resistance, explaining 37% and 19% of the variance seen in cancer patients, respectively. Resistin levels were not different between groups.
Conclusions: Leptin may play a role in the increased insulin resistance seen in cancer patients. However, these patients are resistant to the orexigenic effects of hypoleptinemia. Other mechanisms besides weight loss are responsible for the increased adiponectin level seen in cancer patients. It is unlikely that resistin plays a major metabolic role in this setting.