Increased tumour necrosis factor‐α plasma levels during moderate-intensity exercise in COPD patients

Abstract

Post-training downregulation of muscle tumour necrosis factor (TNF)‐α messenger ribonucleic acid (mRNA) expression and decrease in cellular TNF‐α levels have been reported in the elderly. It is hypothesised that chronic obstructive pulmonary disease (COPD) patients may not show these adaptations due to their reduced ability to increase muscle antioxidant capacity with training. Eleven COPD patients (forced expiratory volume in one second 40±4.4% of the predicted value) and six age-matched controls were studied. Pre- and post-training levels of TNF‐α, soluble TNF receptors (sTNFRs: sTNFR55 and sTNFR75) and interleukin (IL)‐6 in plasma at rest and during exercise and vastus lateralis TNF‐α mRNA were examined. Moderate-intensity constant-work-rate exercise (11 min at 40% of pretraining peak work-rate) increased pretraining plasma TNF‐α levels in COPD patients (from 17±3.2 to 23±2.7 pg·mL−1; p<0.005) but not in controls (from 19±4.6 to 19±3.2 pg·mL−1). No changes were observed in sTNFRs or IL‐6 levels. After 8 weeks' endurance training, moderate-intensity exercise increased plasma TNF‐α levels similarly to pretraining (from 16±3 to 21±4 pg·mL−1; p<0.01). Pretraining muscle TNF‐α mRNA expression was significantly higher in COPD patients than in controls (29.3±13.9 versus 5.0±1.5 TNF‐α/18S ribonucleic acid, respectively), but no changes were observed after exercise or training. It is concluded that moderate-intensity exercise abnormally increases plasma tumour necrosis factor‐α levels in chronic obstructive pulmonary disease patients without exercise-induced upregulation of the tumour necrosis factor‐α gene in skeletal muscle.