Leg blood flow is impaired during small muscle mass exercise in patients with COPD

U W Iepsen, G W Munch, M Rugbjerg, C K Ryrsø, N H Secher, Y Hellsten, P Lange, B K B K Pedersen, P Thaning, S P Mortensen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Skeletal muscle blood flow is regulated to match the oxygen demand and dysregulation could contribute to exercise intolerance in patients with chronic obstructive pulmonary disease (COPD). We measured leg hemodynamics and metabolites from vasoactive compounds in muscle interstitial fluid and plasma at rest, during one-legged knee-extensor exercise, and during arterial infusions of sodium nitroprusside (SNP) and acetylcholine (ACh), respectively. Ten patients with moderate to severe COPD and eight age- and sex-matched healthy controls were studied. During knee-extensor exercise (10 W), leg blood flow was lower in the patients compared with the controls (1.82 0.11 vs. 2.36 0.14 l/min, respectively; P 0.05), which compromised leg oxygen delivery (372 26 vs. 453 32 ml O 2/ min, respectively; P 0.05). At rest, plasma endothelin-1 (vasoconstrictor) was higher in the patients with COPD (P 0.05) and also tended to be higher during exercise (P 0.07), whereas the formation of interstitial prostacyclin (vasodilator) was only increased in the controls. There was no difference between groups in the nitrite/nitrate levels (vasodilator) in plasma or interstitial fluid during exercise. Moreover, patients and controls showed similar vasodilatory capacity in response to both endothelium-independent (SNP) and endothelium-dependent (ACh) stimulation. The results suggest that leg muscle blood flow is impaired during small muscle mass exercise in patients with COPD possibly due to impaired formation of prostacyclin and increased levels of endothelin-1.

Original languageEnglish
JournalJournal of Applied Physiology
Volume123
Issue number3
Pages (from-to)624-631
Number of pages8
ISSN8750-7587
DOIs
Publication statusPublished - 1 Sept 2017
Externally publishedYes

Keywords

  • Journal Article

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