Cachexia has repeatedly been associated with adverse clinical outcomes. The changes seen in cachexia are multidimensional and highly coordinated. The physiologic, metabolic, and behavioral changes of cachexia are tightly regulated by cytokines, which signal the synthesis of acute-phase proteins as well as changes in intermediary metabolism that provide substrate and energy. The metabolic adaptations, notably the increase in the rate of protein degradation, limit the ability of hypercaloric feeding to reverse the depletion of lean mass. Recent studies have demonstrated the ability of anabolic and anticatabolic agents to mitigate the loss of skeletal muscle and to improve clinical outcomes in selected circumstances.
Preclinical initiatives target the cytokine regulation of protein metabolism.
It should be stressed that metabolic manipulation in cachexia could have positive or negative clinical effects, which must be distinguished through appropriate clinical trials. Ann Intern Med. Author and Article Information From Columbia University, New York, New York.