title: Markers of inflammation and disuse in vastus lateralis of chronic obstructive pulmonary disease patients.
abstract: BACKGROUND
  Disuse and/or local inflammation in the muscle cannot be excluded as potential influences for the decreased muscle force in patients hospitalised due to an acute chronic obstructive pulmonary disease (COPD) exacerbation. This study aims to compare expression levels of markers of disuse (insulin-like growth factor-1 (IGF-I), MyoD and myogenin) and inflammation [interleukin-6 (IL-6), IL-8 and tumour necrosis factor-alpha (TNF-alpha)] in the muscle of hospitalised and stable COPD patients and healthy elderly.
  
  
  METHODS
  Muscle biopsies (m. vastus lateralis) were taken in 14 hospitalised COPD patients (aged 68 +/- 8), 11 clinically stable COPD patients (aged 68 +/- 9) and seven healthy subjects (aged 70 +/- 7) to analyse local mRNA expression levels of IL-6, IL-8, TNF-alpha, IGF-I and protein expression levels of IGF-I, MyoD and myogenin. Relationships of these expression levels with lung and skeletal muscle function were investigated.
  
  
  RESULTS
  IGF-I mRNA and MyoD protein levels were significantly lower in hospitalised patients compared to healthy subjects. MyoD protein levels were positively related to quadriceps force. Muscle IL-6 and IL-8 expression in hospitalised patients was similar compared to stable patients and healthy subjects and was not related to expression levels of muscle markers of disuse or quadriceps force. Muscle TNF-alpha and myogenin were not detected.
  
  
  CONCLUSIONS
  Decreased expression levels of muscle IGF-I and MyoD in hospitalised patients suggest a potential influence of disuse in the increased muscle weakness during an acute COPD exacerbation. This study did not find any evidence supporting local inflammation via IL-6, IL-8 and/or TNF-alpha in the vastus lateralis muscle of COPD patients.
authors: Respiratory Muscle Research Unit, Laboratory of Pneumology, Faculty of Medicine, Katholieke Universiteit Leuven, Leuven, Belgium.
authors: T
authors: T
authors: Crul
authors: M A
authors: MA
authors: Spruit
authors: G
authors: G
authors: Gayan-Ramirez
authors: R
authors: R
authors: Quarck
authors: R
authors: R
authors: Gosselink
authors: T
authors: T
authors: Troosters
authors: F
authors: F
authors: Pitta
authors: M
authors: M
authors: Decramer
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I; D015850:Interleukin-6 / Q000097:blood; D016209:Interleukin-8 / Q000097:blood; D008297:Male; D008875:Middle Aged; D009133:Muscular Atrophy / Q000503:physiopathology*; D017570:MyoD Protein; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000503:physiopathology*; D012333:RNA, Messenger / Q000302:isolation & purification; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D015415:Biomarkers; D015850:Interleukin-6; D016209:Interleukin-8; D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D007334:Insulin-Like Growth Factor I