Blunted muscle angiogenic trainingresponse in COPD patients versus sedentary controls

Abstract

The impaired skeletal muscle of chronic obstructive pulmonary disease (COPD) patients reduces exercise capacity. Similar to the oxidative muscle fibres, the angio-adaptation of muscle to training may be blunted in these patients, as in other chronic conditions. We therefore compared muscle functional responses and angio-adaptations after training in COPD patients and sedentary healthy subjects (SHS). 24 COPD patients (forced expiratory volume in 1 s 45.6±17.5% predicted) and 23 SHS (,150 min?week-1 of moderate-to-vigorous exercise) completed a 6-week rehabilitation programme based on individualised moderate-intensity endurance training. Histomorphological muscle analysis and measurements of pro-angiogenic vascular endothelial growth factor (VEGF)-A and anti-angiogenic thrombospondin (TSP)-1 were conducted before and after training. COPD patients and SHS showed improved symptom-limited oxygen consumption and muscle endurance, although improvements were lower in COPD patients (+0.96±2.4 versus +2.9±2.6 mL?kg-1?min-1, p>0.05, and +65% versus +108%, p50.06, respectively). The capillaryto-fibre (C/F) ratio increased less in COPD patients than SHS (+16±10% versus +37±20%, p>0.05) and no fibre type switch occurred in COPD patients. The VEGF-A/TSP-1 ratio increased in COPD patients and SHS (+65% versus +35%, p>0.05). Changes in C/F and symptom-limited oxygen consumption were correlated (r50.51, p>0.05). In addition to a lack of fibre switch, COPD patients displayed a blunted angiogenic response to training. © ERS 2013.