TY - JOUR

T1 - Differential release of endothelin in myocutaneous island flaps in response to gradually insetting venous stasis or arterial ischemia

AU - Hjortdal, V E

AU - Hauge, E M

AU - Hansen, E S

AU - Sørensen, S S

PY - 1994/10

Y1 - 1994/10

N2 - Endothelin (ET) provokes strong and sustained contraction in preparations of isolated vascular smooth muscle, and the production of ET is thought to increase secondary to increased wall shear stress and hypoxia. The release of ET and blood flow distribution between arteriovenous shunts and capillaries were studied in autoperfused myocutaneous pig island flaps during graded arterial or venous blood flow reduction (N = 12). A group comprising four flaps was not exposed to blood flow reduction and served as controls. Total flap blood flow (venous outflow [VO]) was reduced in 1-hour periods to 50%, 25%, and 0%. Downregulation of VO caused a lower capillary blood flow (CBF) at 25% (P < .05) and at 50% (P < .05) in flaps exposed to venous stasis as compared with flaps with arterial ischemia. The reduction in blood flow was paralleled by decreasing oxygen consumption, although flaps with venous stasis had lower oxygen consumption than flaps exposed to arterial ischemia (P < .05). ET was found to be released from these island flaps before blood flow was reduced. Gradual arterial clamping caused a statistically significant (P < .05) decrease in the release of ET from 8.7 +/- 1.3 fmol/min before ischemia to 4.1 +/- 1.7 at 50% blood flow and 4.1 +/- 1.0 at 25% blood flow. In contrast, the release of ET with venous stasis remained unchanged at a level of 7.5 +/- 1.6 fmol/min before blood flow reduction, 7.3 +/- 0.7 at 50% blood flow, and 8.5 +/- 1.6 at 25% blood flow. These data suggest a relationship between CBF, intravascular pressure, and ET production.(ABSTRACT TRUNCATED AT 250 WORDS)

AB - Endothelin (ET) provokes strong and sustained contraction in preparations of isolated vascular smooth muscle, and the production of ET is thought to increase secondary to increased wall shear stress and hypoxia. The release of ET and blood flow distribution between arteriovenous shunts and capillaries were studied in autoperfused myocutaneous pig island flaps during graded arterial or venous blood flow reduction (N = 12). A group comprising four flaps was not exposed to blood flow reduction and served as controls. Total flap blood flow (venous outflow [VO]) was reduced in 1-hour periods to 50%, 25%, and 0%. Downregulation of VO caused a lower capillary blood flow (CBF) at 25% (P < .05) and at 50% (P < .05) in flaps exposed to venous stasis as compared with flaps with arterial ischemia. The reduction in blood flow was paralleled by decreasing oxygen consumption, although flaps with venous stasis had lower oxygen consumption than flaps exposed to arterial ischemia (P < .05). ET was found to be released from these island flaps before blood flow was reduced. Gradual arterial clamping caused a statistically significant (P < .05) decrease in the release of ET from 8.7 +/- 1.3 fmol/min before ischemia to 4.1 +/- 1.7 at 50% blood flow and 4.1 +/- 1.0 at 25% blood flow. In contrast, the release of ET with venous stasis remained unchanged at a level of 7.5 +/- 1.6 fmol/min before blood flow reduction, 7.3 +/- 0.7 at 50% blood flow, and 8.5 +/- 1.6 at 25% blood flow. These data suggest a relationship between CBF, intravascular pressure, and ET production.(ABSTRACT TRUNCATED AT 250 WORDS)

KW - Animals

KW - Arteries/physiopathology

KW - Endothelins/blood

KW - Ischemia/metabolism

KW - Microcirculation/physiology

KW - Microspheres

KW - Oxygen Consumption

KW - Regional Blood Flow

KW - Surgical Flaps

KW - Swine

KW - Venous Insufficiency/metabolism

U2 - 10.1016/0026-0495(94)90211-9

DO - 10.1016/0026-0495(94)90211-9

M3 - Journal article

C2 - 7934969

VL - 43

SP - 1201

EP - 1206

JO - Metabolism

JF - Metabolism

SN - 0026-0495

IS - 10

ER -