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

Y1 - 2017

N2 - Skeletal muscle blood flow is regulated to match the oxygen demand and dysregulation could contribute to exercise intolerance in patients with 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 versus 2.36±0.14 L/min, respectively, P<0.05) which compromised leg oxygen delivery (372±26 versus 453±32 mLO2/min, respectively, P<0.05). At rest, plasma endothelin-1 (vasoconstrictor) was higher in the COPD patients (P<0.05) and also tended to be higher during exercise (p=0.07), while 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 suggests 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 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 versus 2.36±0.14 L/min, respectively, P<0.05) which compromised leg oxygen delivery (372±26 versus 453±32 mLO2/min, respectively, P<0.05). At rest, plasma endothelin-1 (vasoconstrictor) was higher in the COPD patients (P<0.05) and also tended to be higher during exercise (p=0.07), while 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 suggests 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

VL - 123

SP - 624

EP - 631

JO - Journal of Applied Physiology

JF - Journal of Applied Physiology

SN - 8750-7587

IS - 3

ER -