RT Journal Article
SR Electronic
T1 Characterizing metabolic abnormality and adipose tissue infiltration in skeletal muscle of COPD patients using 31P MR spectroscopy and MRI imaging
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 1668
VO 40
IS Suppl 56
A1 Graziele Coissi
A1 Gregory Shields
A1 Pillar Jimenez-Royo
A1 Giulio Gambarota
A1 Raul Dimber
A1 Nicholas Hopkinson
A1 Paul Mattrews
A1 Andrew Brown
A1 Michael Polkey
YR 2012
UL http://erj.ersjournals.com/content/40/Suppl_56/1668.abstract
AB Background: Anaerobic metabolism (AM) is an extra-pulmonary manifestation of COPD. 31P Magnetic Resonance Spectroscopy (31P MRS) is an established technique to assess the oxidative capacity of skeletal muscles, but is unknown whether similar changes occur in the upper and lower limbs. Dixon MRI has been demonstrated as a quantitative technique to determine water and fat levels in tissues.Objective: We hypothesised that AM would occur predominantly in the legs and that intermuscular adipose tissue (IMAT) infiltration would be a predictor of AM.Methods: 31P – MRS data for the quadriceps (quads) and biceps were obtained during 2 min. and 8 secs of endurance exercise and pre and post-exercise. Quads and its sub-muscle group cross-sectional area and IMAT were measured using Dixon MR imaging. Quads maximal voluntary strength (QMVC), six minute walking test (6MWT) and fat free mass index (FFMI) were additionally performed.Results: Data were obtained for 14 patients with COPD (age 66 ± 5.73) with a mean ±SD percentage predicted of forced expiratory volume in 1s (FEV1) of 36.5 ± 12.7 and 14 age matched healthy controls (age 65 ± 6, FEV1 pred% 110 ± 6.5). Patients with COPD had prolonged quads phospholcreatine recovery time [PCr (t1/2)],(p=0.006) and lower nadir intramuscular pH (p=0.002) as compared to controls. Biceps metabolism was not different between COPD patients and controls. Quads IMAT was 32% greater in COPD patients than controls (p=0.033).Conclusion: AM activation appears confined to the quads in COPD. We also suggest that IMAT, as measured by Dixon MRI, is a sensitive biomarker for AM.