Article Text
Statistics from Altmetric.com
S72 QUADRICEPS MUSCLE EXPRESSION OF MYOSTATIN IN PATIENTS WITH COPD
1W. D. Man, 2S. A. Sathyapala, 2J. Riddoch-Contreras, 2A. Lewis, 1G. Marsh, 1M. I. Polkey, 2P. R. Kemp. 1Royal Brompton & Harefield NHS Foundation Trust, London, UK, 2Molecular Medicine, Imperial College, London, UK
Introduction and Objectives Quadriceps muscle weakness is well recognised in chronic obstructive pulmonary disease (COPD), and is associated with reduced exercise capacity, impaired health status and increased mortality. The cause of quadriceps weakness in COPD is multifactorial, but chronic daily inactivity is a likely major contributor. Myostatin is a negative regulator of muscle mass as demonstrated in naturally occurring human and animal genetic mutations, and genetic rodent models. A recent cross-sectional study showed increased expression of vastus lateralis myostatin mRNA in cachexic patients with COPD compared with healthy controls (Plant et al 2009). We hypothesised that vastus lateralis expression of myostatin would negatively correlate with quadriceps strength.
Methods 18 patients with COPD were clinically phenotyped with measurements of lung function, quadriceps muscle strength (quadriceps maximum voluntary contraction normalised to body mass index: QMVC/BMI) and endurance (time for quadriceps force to fall to 80%: T80), exercise capacity (6 minute walk distance: 6MWD), daily physical activity (locomotion time measured by tri-axial accelerometry: Lo) and health status (St George’s Respiratory Questionnaire: SGRQ). Biopsy of the vastus lateralis muscle was performed using a Bergstrom needle. Real-time PCR for expression levels of transcripts for myostatin was performed in duplicate wells, and normalised to a housekeeping gene. The relationship between clinical variables and quadriceps myostatin expression was determined by Spearman rank correlation.
Results Baseline clinical characteristics are outlined in table 1. Quadriceps muscle myostatin mRNA expression was negatively correlated with QMVC/BMI (r = −0.50, p<0.04), T80 (r = −0.53, p<0.03), 6MWD (r = −0.62, p<0.01) and Lo (r = −0.54, p<0.04).
Conclusions Myostatin may play a role in the development of quadriceps …