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

TY - JOUR

T1 - Leg blood flow is impaired during small muscle mass exercise in patients with COPD

AU - Iepsen, Ulrik Winning

AU - Munch, Gregers Druedal Wibe

AU - Rugbjerg, Mette

AU - Ryrsø, Camilla Koch

AU - Secher, Niels H.

AU - Hellsten, Ylva

AU - Lange, Peter

AU - Pedersen, Bente Klarlund

AU - Thaning, Pia

AU - Mortensen, Stefan P

N1 - CURIS 2017 NEXS 246

PY - 2017/9

Y1 - 2017/9

N2 - 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 O2/ 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.

AB - 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 O2/ 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.

KW - Hemodynamics

KW - Extracellular fluid

KW - Vasodilator agents

U2 - 10.1152/japplphysiol.00178.2017

DO - 10.1152/japplphysiol.00178.2017

M3 - Journal article

C2 - 28729387

SN - 8750-7587

VL - 123

SP - 624

EP - 631

JO - Journal of Applied Physiology

JF - Journal of Applied Physiology

IS - 3

ER -