RT Journal Article
SR Electronic
T1 Adaptation of the diaphragm and the vastus lateralis in mild-to-moderate COPD
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 971
OP 979
DO 10.1183/09031936.04.00020204
VO 24
IS 6
A1 M. Doucet
A1 R. Debigaré
A1 D.R. Joanisse
A1 C. Côté
A1 P. LeBlanc
A1 J. Grégoire
A1 J. Deslauriers
A1 R. Vaillancourt
A1 F. Maltais
YR 2004
UL http://erj.ersjournals.com/content/24/6/971.abstract
AB The chronology of diaphragm and vastus lateralis adaptation in chronic obstructive pulmonary disease (COPD) has not been studied. The hypothesis of this study was that muscle changes would occur earlier in the diaphragm than in the vastus lateralis in COPD, a finding that would suggest that local factors would be more important than systemic factors in determining the muscle phenotypic expression, at least in mild-to-moderate disease. The adaptation of the vastus lateralis and diaphragm muscles was evaluated in patients with mild-to-moderate COPD and in subjects with normal pulmonary function. In both groups, the oxidative potential and the number of lipofuscin inclusions were higher in the diaphragm than in the vastus lateralis. Compared to control, the diaphragm in COPD had a higher oxidative capacity and a higher proportion of type I fibres, with a reciprocal decrease in type IIA fibres, while there was no difference in diaphragmatic cross sectional areas, capillarisation and lipofuscin inclusions. No significant differences were found in the vastus lateralis from both groups. In conclusion, these data indicate that the diaphragm in controls and in chronic obstructive pulmonary disease has a higher oxidative potential than the vastus lateralis, and that muscle adaptation occurs earlier in the diaphragm than in the vastus lateralis in mild-to-moderate chronic obstructive pulmonary disease. This study was supported by Canadian Institutes of Health Research grant MOP-53135. R. Debigaré was the recipient of a PhD training award from the Fonds de la Recherche en Santé du Québec. F. Maltais is a research scholar of the Fonds de la Recherche en Santé du Québec.