title: Physical performance and muscular characteristics in different stages of COPD.
abstract: This study has examined exercise capacity and muscle morphology in patients with different severities of chronic obstructive pulmonary disease (COPD). Twenty-three patients and 12 healthy matched controls were recruited. Based on the severity of airflow obstruction, patients were divided into two subgroups. Exercise capacity was determined using a 6-min walk test. Muscle fiber composition, fiber area and number of satellite cells/muscle fiber were determined in muscle biopsies using immunohistochemistry. A progressive decline in exercise capacity was noted with ascending disease severity. Furthermore, a correlation between reduction in exercise capacity and changes in muscle fiber composition was observed in COPD. The group with severe and very severe COPD had a lower proportion of type I and a higher proportion of type IIa fibers compared with the other groups. In severe and very severe COPD, a reduction in fiber area of type IIa fibers was also seen. The number of satellite cells/muscle fiber did not differ between the groups. In conclusion, a decline in exercise capacity occurs already in mild and moderate COPD, indicating that the 6-min walk test is a reliable indicator of disease severity. Furthermore, changes in skeletal muscle morphology are associated with disease severity while muscle regenerative capacity is not altered.
authors.affiliation: School of Medical Sciences, Orebro University, Orebro, Sweden. gabriella.eliason@ikm.oru.se
authors.forename: G
authors.initials: G
authors.lastname: Eliason
authors.forename: S
authors.initials: S
authors.lastname: Abdel-Halim
authors.forename: B
authors.initials: B
authors.lastname: Arvidsson
authors.forename: F
authors.initials: F
authors.lastname: Kadi
authors.forename: K
authors.initials: K
authors.lastname: Piehl-Aulin
mesh_terms: D000368:Aged; D001823:Body Composition; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D012720:Severity of Illness Index