Cytokine Profile in Quadriceps Muscles of Patients with Severe Chronic Obstructive Pulmonary Disease

BACKGROUND: Systemic proinflammatory cytokines and oxidative stress have been described in association with peripheral muscle wasting and weakness of patients with severe chronic obstructive pulmonary disease (COPD), but their expression in skeletal muscle is unknown. Objectives of the present study were to determine muscle protein levels of selected cytokines in patients with COPD and to study their relationships with protein carbonylation as a marker of oxidative stress, quadriceps function, and exercise capacity. METHODS: We conducted a cross-sectional study in which 36 cytokines were detected using a human antibody array in quadriceps specimens obtained from 19 patients with severe COPD and 7 healthy controls. Subsequently, selected cytokines [tumor necrosis factor (TNF)-alpha, TNF-alpha receptors I and II, interleukin (IL)-6, interferon-gamma, transforming growth factor (TGF)-beta, and vascular endothelial growth factor (VEGF)], as well as protein carbonylation (oxidative stress index) were determined using enzyme-linked immunosorbent assay (ELISA) in all muscles. RESULTS: As compared to controls, vastus lateralis of COPD patients showed significantly lower protein ELISA levels of TNF-alpha, which positively correlated with their quadriceps function, TNF-alpha receptor II, and VEGF. Protein ELISA levels of IL-6, interferon-gamma, and TGF-beta did not differ between patients and controls. Quadriceps protein carbonylation was greater in the patients and inversely correlated with quadriceps strength amongst them. CONCLUSIONS: These findings do not support the presence of a pro-inflammatory environment within the quadriceps muscles of clinically and weight stable patients with severe COPD, despite evidence for increased oxidative stress and the presence of muscle weakness

Validity of physical activity monitors during daily life in patients with COPD.

Symptoms during physical activity (PA) and physical inactivity are COPD. Our aim was to evaluate the validity and usability of six activity in patients with COPD against the doubly labelled water (DLW) indirect calorimetry method.Eighty COPD patients (age 68+/-6 years, FEV1 57+/-19% predicted) recruited in four centres each wore simultaneously three or six commercially available monitors validated in chronic conditions for consecutive days. A priori validity criteria were defined. These ability to explain total energy expenditure (TEE) variance through regression analysis, using TEE as the dependent variable with total body (TBW) plus several PA monitors outputs as independent variables; and with DLW measured activity energy expenditure (AEE).The Actigraph GT3X DynaPort MoveMonitor best explained the majority of the TEE variance not explained by TBW (53% and 70% respectively) and showed the most correlations with AEE (r=0.71 p<0.001, r=0.70 p<0.0001, of this study should guide users in choosing valid activity monitors for or for clinical use in patients with chronic diseases such as COPD

Diaphragm function in chronic obstructive pulmonary disease

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