Training depletes muscle glutathione in patients with chronic obstructive pulmonary disease and low body mass index

Background: A physiological increase in muscle glutathione after training is not seen in patients with chronic obstructive pulmonary disease (COPD), indicating abnormal peripheral muscle adaptations to exercise. Objective: We hypothesized that oxidative stress is primarily associated with low body mass index (BMI). Methods: Eleven patients with preserved BMI (BMIN:28.2 +/- 1.2 kg.m(-2)), 9 patients with low BMI (BMIL: 19.7 +/- 0.60 kg.m(-2)) and 5 age-matched controls (26.5 +/- 0.9 kg.m(-2)) were studied before and after 8 weeks of high-intensity endurance training. Reduced glutathione (GSH) and gamma-glutamyl cysteine synthase heavy-subunit chain mRNA expression (gamma GCS-HS mRNA) were measured in the vastus lateralis. Results: After training, exercise capacity increased (Delta VO(2)PEAK, 13 +/- 5.2%; 10 +/- 5.6% and 15 +/- 4.3% in BMIL, BMIN and controls, respectively; p < 0.05 each). GSH levels decreased in BMIL (from 5.2 +/- 0.7 to 3.7 +/- 0.8 nmol/mg protein, Delta GSH -1.5 +/- 0.7 nmol/mg protein, p ! 0.05); no changes were seen in BMIN (from 5.4 +/- 0.7 to 6.7 +/- 0.9 nmol/mg protein, Delta GSH 1.3 +/- 0.9 nmol/mg protein), whereas GSH markedly increased in controls ( from 4.6 +/- 1 to 8.7 +/- 0.4 nmol/mg protein, Delta GSH 4.1 +/- 1 nmol/mg protein, p < 0.01). Delta GSH in BMIL was different from Delta GSH in BMIN and controls (p < 0.05, each). Consistent changes were observed in gamma GCS-HS mRNA expression. Conclusions: GSH depletion after training in BMIL may suggest that oxidative stress plays a key role in muscle wasting in COPD patients. Copyright (C) 2006 S. Karger AG, Basel.