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 (BMI(N): 28.2 +/- 1.2 kg.m(-2)), 9 patients with low BMI (BMI(L): 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 (gammaGCS-HS mRNA) were measured in the vastus lateralis.


RESULTS
After training, exercise capacity increased (DeltaVO(2)PEAK, 13 +/- 5.2%; 10 +/- 5.6% and 15 +/- 4.3% in BMI(L), BMI(N) and controls, respectively; p < 0.05 each). GSH levels decreased in BMI(L) (from 5.2 +/- 0.7 to 3.7 +/- 0.8 nmol/mg protein, DeltaGSH -1.5 +/- 0.7 nmol/mg protein, p < 0.05); no changes were seen in BMI(N) (from 5.4 +/- 0.7 to 6.7 +/- 0.9 nmol/mg protein, DeltaGSH 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, DeltaGSH 4.1 +/- 1 nmol/mg protein, p < 0.01). DeltaGSH in BMI(L) was different from DeltaGSH in BMI(N) and controls (p < 0.05, each). Consistent changes were observed in gammaGCS-HS mRNA expression.


CONCLUSIONS
GSH depletion after training in BMI(L) may suggest that oxidative stress plays a key role in muscle wasting in COPD patients.
Rabinovich
Roberto A
RA
Servei de Pneumologia, Hospital Clínic, Facultat de Medicina, Barcelona, Spain. rrabinov@clinic.ub.es
Ardite
Esther
E
Mayer
Ana Maria
AM
Polo
Maite Figueras
MF
Vilaró
Jordi
J
Argilés
Josep M
JM
Roca
Josep
J
D000368:Aged; D015992:Body Mass Index; D002851:Chromatography, High Pressure Liquid; D015444:Exercise / Q000502:physiology*; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism* / Q000503:physiopathology
D005978:Glutathione