Cachexia is a syndrome of weight loss, anorexia and fatigue that significantly impacts quality of life in terminally ill cancer patients. Skeletal muscle wasting is a major factor associated with fatigue and interventions to preserve muscle mass in these patients are needed. Tumor necrosis factor (TNF), a pro-inflammatory cytokine, is thought to play a major role in the skeletal muscle wasting of cancer cachexia. The preservation of muscle mass in tumor-bearing animals treated with indomethacin, a nonsteroidal anti-inflammatory drug that inhibits cyclo-oxygenase activity, suggests that prostanoid products of arachidonic acid are also involved in the skeletal muscle wasting of cancer cachexia. Conjugated linoleic acid (CLA) is a positional isomer of linoleic acid, an essential fatty acid, which has been shown to reduce the synthesis of TNF by activated macrophages, and to reduce the activity of cyclo-oxygenase and synthesis of PGE2 from arachidonic acid. In the present study, we examined the effects of a diet supplemented with .5% CLA on skeletal muscle wasting in groups of 6 mice with and without tumors. Mice fed .5% CLA over the course of 21 days of tumor growth had greater muscle mass than mice fed the control diet. CLA did not alter muscle mass in the healthy control animals. Levels of TNF type 1 receptor were increased in muscles of tumor bearing animals, and were lowered to control levels in mice fed CLA. These data suggest that CLA reduces the catabolic effects of TNF in skeletal muscle of tumor-bearing mice. Further research using other animal models of cancer cachexia is needed to determine if CLA might be useful in the treatment of muscle wasting in patients with cancer cachexia.
Session #1216 - Poster Session II
The 29th Annual MNRS Research Conference (April 1-4, 2005)