MECHANISMS OF WEIGHT LOSS IN COPD

Chronic obstructive pulmonary disease (COPD) is characteristically associated with important systemic features such as weight loss, skeletal muscle atrophy, and systemic inflammation. Muscle atrophy leading to weight loss in COPD is associated with a poor prognosis, although our understanding of the mechanisms of weight loss in COPD is limited. In this issue of Thorax Agusti and colleagues report the results of a study of the upregulation of the nuclear transcription factor NF-κB in muscle biopsy specimens of patients with COPD. They found a 30% increase in NF-κB activity in patients of low body weight compared with those of normal body weight, and upregulation of the inducible form of nitric oxide synthase (iNOS) in the skeletal muscle of low body weight COPD patients. The authors also suggest that the higher levels of nitric oxide (NO) in the presence of upregulated iNOS can contribute to skeletal muscle atrophy either by enhancing skeletal muscle apoptosis or stimulating …