Oxidative stress may differentially regulate protein loss within peripheral muscles of severe chronic obstructive pulmonary disease (COPD) patients exhibiting different body composition.Oxidation levels of proteins, myosin heavy chain (MyHC) and myonuclei, superoxide anion, antioxidants, actin, creatine kinase, carbonic anhydrase-3, ubiquitin-proteasome system, redoxsignalling pathways, inflammation and muscle structure, and damage were quantified in limb muscles of severe COPD patients with and without muscle wasting, and in sedentary controls.Compared with controls, in the quadriceps of muscle-wasted COPD patients, levels of protein carbonylation, oxidation of MyHC and myonuclei, superoxide anion production, superoxide dismutase, total protein ubiquinitation, E2 14k , atrogin-1, FoxO1 and p65 were higher, while content of MyHC, creatine kinase, carbonic anhydrase-3, myogenin, and fast-twitch fibre size were decreased. Importantly, in nonwasted COPD patients, where MyHC was more oxidised than in controls, its content was preserved. Muscle inflammation and glutathione levels did not differ between patients and controls. In all patients, muscle structure abnormalities were increased, while muscle force and exercise capacity were reduced.In severe COPD, while muscle oxidative stress increases regardless of their body composition, protein ubiquitination and loss of MyHC were enhanced only in patients exhibiting muscle atrophy. Oxidative stress does not seem to directly modulate muscle protein loss in these patients.

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. The 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 seven healthy controls. Subsequently, selected cytokines (tumour necrosis factor (TNF)a, TNFa receptors I and II, interleukin (IL) 6, interferon c, transforming growth factor (TGF) b and vascular endothelial growth factor (VEGF)), as well as protein carbonylation (oxidative stress index) were determined using an enzyme linked immunosorbent assay (ELISA) in all muscles. Results: Compared with controls, the vastus lateralis of patients with COPD showed significantly lower protein ELISA levels of TNFa, which positively correlated with their quadriceps function, TNFa receptor II and VEGF. Protein ELISA levels of IL6, interferon c and TGFb did not differ between patients and controls. Quadriceps protein carbonylation was greater in patients and inversely correlated with quadriceps strength among them. Conclusions: These findings do not support the presence of a proinflammatory 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.Muscle dysfunction, characterised by reduced muscle strength and endurance, is one of the most important systemic manifestations of advanced chronic obstructive pulmonary disease (COPD), leading to reduced exercise tolerance, quality of life and survival.

The aims of this study were to investigate whether the impairment in endurance of limb muscles is a general finding in chronic obstructive pulmonary disease (COPD) patients, affecting even those with mild-to-moderate disease or relatively normal physical activity. In addition, this study aimed to determine the physiopathology of exhaustion in local endurance tests and whether the reduction in quadriceps endurance can be predicted from muscle strength measurements.A total of 75 volunteers were assigned to one of two groups according to pulmonary function tests: COPD patients or healthy age-matched controls. Functional assessment included both quadriceps strength (maximum voluntary contraction (QMVC)), and quadriceps endurance (contractions against a load equivalent to 10% QMVC until task failure or for up to a limiting time of 30 min (QTlim)).COPD patients showed a decrease of y43% in QMVC and y77% in QTlim compared with controls. Task failure occurred only in COPD patients and was due to muscle fatigue, since limiting symptoms were associated with a decrease in the median frequency of quadriceps electromyographical signal and a reversible decrease in QMVC. The impairment in skeletal muscle endurance was present even in patients with mild-tomoderate airflow obstruction and individuals with relatively normal physical activity, and was irrespective of lung function variables, anthropometrical data or quadriceps strength.Peripheral muscle endurance was impaired in chronic obstructive pulmonary disease patients, even in those with relatively normal physical activity and mild-to-moderate airflow obstruction. This impairment associated with an early onset of muscle fatigue and could not be predicted from the severity of the disease or the reduction in quadriceps strength. Eur Respir J 2004; 24: 129-136.

The impact of apathy on health-related quality of life (HRQOL) in recently diagnosed Parkinson's disease (PD) has not been systematically investigated. The objective of this cross-sectional survey (ANIMO study) was to examine the contribution of apathy to HRQOL in a Spanish sample of recently diagnosed PD patients. PD patients, diagnosed within 2 years of inclusion, were recruited at 102 outpatient clinics in 82 communities throughout Spain. Apathy was quantified using the Lille Apathy Rating Scale and HRQOL with the EuroQol-5D questionnaire. A mean EuroQol-5D index score of 0.89 obtained from population references in Spain was used as the cutoff for this study. The relationship between apathy and the dichotomized EuroQol-5D index score (<0.89 [lower HRQOL] vs ≥0.89 [reference]) was examined using multiple logistic regression analysis, adjusting for sociodemographic and clinical variables. We consecutively recruited 557 patients (60.3% men) with a mean age of 68.8 ± 9.7 years. Apathy was diagnosed in 291 (52.2%) and was related to problems in each of the EuroQoL dimensions. Apathetic PD patients showed EuroQol-5D index scores significantly lower than those without apathy (0.64 vs 0.83). In an adjusted model, apathetic PD patients were 2.49 times more likely to have lower HRQOL than nonapathetic patients (odds ratio, 2.49; 95% confidence interval, 1.49-4.15, P < 0.01). Apathy is very common in those with recently diagnosed PD and is one of the major clinical determinants of HRQOL in this disease. It should be one of the primary concerns among clinicians who provide treatment to individuals affected by PD.