RT Journal Article
SR Electronic
T1 Skeletal muscle metabolism in active cystic fibrosis (CF) patients with light/moderate pulmonary dysfunction
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP PA2242
DO 10.1183/13993003.congress-2015.PA2242
VO 46
IS suppl 59
A1 Samuel Verges
A1 Nicolas Decorte
A1 Mathieu Gruet
A1 Boubou Camara
A1 Sébastien Quetant
A1 Laurent Mely
A1 Jean-Marc Vallier
A1 Bernard Wuyam
YR 2015
UL http://erj.ersjournals.com/content/46/suppl_59/PA2242.abstract
AB Background: Specific alterations in skeletal muscle related to genetic defect may be present in adults with CF. Impaired locomotor muscle metabolism may contribute to exercise intolerance in CF without severe pulmonary dysfunction.Aims and objectives: We hypothesized that patients with CF would have altered muscle metabolism which may reduce exercise performances.Methods: Fifteen adults with CF and 15 healthy controls matched for age, gender and physical activity performed a maximal cycling test and an evaluation of calf muscle energetics by 31P magnetic resonance spectroscopy at rest and during plantar flexions to exhaustion.Results: Maximal cycling test revealed lower exercise capacities in CF (VO2peak 2.44±0.11 vs. 3.44±0.23 L.Min-1, P=0.03; maximal workload 186±96 vs. 296±71 W, P=0.01). At rest, all calf muscle phosphorus metabolites and pHi were similar in CF and controls (P>0.05). The total work performed during plantar flexions was significantly lower in CF (1173±379 and 1462±295 J; P=0.013). At exhaustion, PCr concentration was similarly reduced in both groups (CF -33%, controls -34%, P<0.05), with a significantly greater PCr degradation at identical absolute workload in CF patients. This difference disappeared when workload was normalized for differences in muscle mass (cross sectional area: CF 38.1±11.1 vs. controls 51.6±14.3 cm²; P=0.011). Pi/PCr ratio and end-exercise pHi were similar between groups.Conclusion: No abnormal metabolic response was detected in skeletal muscle of CF patients. The impairment in exercise performance is probably due to the reduced muscle mass and ventilatory limitation in CF.