Format

Send to

Choose Destination
J Appl Physiol (1985). 2013 May;114(9):1222-34. doi: 10.1152/japplphysiol.00981.2012. Epub 2013 Mar 21.

Pathophysiology of muscle dysfunction in COPD.

Author information

1
Servei de Pneumologia, Hospital del Mar-IMIM, Universitat Pompeu Fabra, Barcelona, Spain. jgea@parcdesalutmar.cat

Abstract

Muscle dysfunction often occurs in patients with chronic obstructive pulmonary disease (COPD) and may involve both respiratory and locomotor (peripheral) muscles. The loss of strength and/or endurance in the former can lead to ventilatory insufficiency, whereas in the latter it limits exercise capacity and activities of daily life. Muscle dysfunction is the consequence of complex interactions between local and systemic factors, frequently coexisting in COPD patients. Pulmonary hyperinflation along with the increase in work of breathing that occur in COPD appear as the main contributing factors to respiratory muscle dysfunction. By contrast, deconditioning seems to play a key role in peripheral muscle dysfunction. However, additional systemic factors, including tobacco smoking, systemic inflammation, exercise, exacerbations, nutritional and gas exchange abnormalities, anabolic insufficiency, comorbidities and drugs, can also influence the function of both respiratory and peripheral muscles, by inducing modifications in their local microenvironment. Under all these circumstances, protein metabolism imbalance, oxidative stress, inflammatory events, as well as muscle injury may occur, determining the final structure and modulating the function of different muscle groups. Respiratory muscles show signs of injury as well as an increase in several elements involved in aerobic metabolism (proportion of type I fibers, capillary density, and aerobic enzyme activity) whereas limb muscles exhibit a loss of the same elements, injury, and a reduction in fiber size. In the present review we examine the current state of the art of the pathophysiology of muscle dysfunction in COPD.

KEYWORDS:

deconditioning; exacerbations; exercise; hyperinflation; limb muscles; muscle dysfunction; muscle wasting; respiratory muscles

PMID:
23519228
DOI:
10.1152/japplphysiol.00981.2012
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Atypon
Loading ...
Support Center