TY - JOUR

T1 - Tumor necrosis factor-alpha inhibits insulin's stimulating effect on glucose uptake and endothelium-dependent vasodilation in humans

AU - Rask-Madsen, Christian

AU - Domínguez, Helena

AU - Ihlemann, Nikolaj

AU - Hermann, Thomas

AU - Køber, Lars

AU - Torp-Pedersen, Christian

N1 - Keywords: Acetylcholine; Adult; Arteriosclerosis; Blood Flow Velocity; Brachial Artery; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Endothelium, Vascular; Forearm; Glucose; Humans; Inflammation; Infusions, Intra-Arterial; Insulin; Insulin Antagonists; Insulin Resistance; Male; Nitric Oxide; Nitroprusside; Tumor Necrosis Factor-alpha; Vasodilation; omega-N-Methylarginine

PY - 2003

Y1 - 2003

N2 - BACKGROUND: Inflammatory mechanisms could be involved in the pathogenesis of both insulin resistance and atherosclerosis. Therefore, we aimed at examining whether the proinflammatory cytokine tumor necrosis factor (TNF)-alpha inhibits insulin-stimulated glucose uptake and insulin-stimulated endothelial function in humans. METHODS AND RESULTS: Healthy, lean male volunteers were studied. On each study day, 3 acetylcholine (ACh) or sodium nitroprusside (SNP) dose-response studies were performed by infusion into the brachial artery. Before and during the last 2 dose-response studies, insulin and/or TNF-alpha were coinfused. During infusion of insulin alone for 20 minutes, forearm glucose uptake increased by 220+/-44%. This increase was completely inhibited during coinfusion of TNF-alpha (started 10 min before insulin) with a more pronounced inhibition of glucose extraction than of blood flow. Furthermore, TNF-alpha inhibited the ACh forearm blood flow response (P<0.001), and this inhibition was larger during insulin infusion (P=0.01) but not further increased by NG-monomethyl-L-arginine acetate (P=0.2). Insulin potentiated the SNP response less than the ACh response and the effect of TNF-alpha was smaller (P<0.001); TNF-alpha had no effect on the SNP response without insulin infusion. Thus, TNF-alpha inhibition of the combined response to insulin and ACh was likely mediated through inhibition of NO production. CONCLUSIONS: These results support the concept that TNF-alpha could play a role in the development of insulin resistance in humans, both in muscle and in vascular tissue.

AB - BACKGROUND: Inflammatory mechanisms could be involved in the pathogenesis of both insulin resistance and atherosclerosis. Therefore, we aimed at examining whether the proinflammatory cytokine tumor necrosis factor (TNF)-alpha inhibits insulin-stimulated glucose uptake and insulin-stimulated endothelial function in humans. METHODS AND RESULTS: Healthy, lean male volunteers were studied. On each study day, 3 acetylcholine (ACh) or sodium nitroprusside (SNP) dose-response studies were performed by infusion into the brachial artery. Before and during the last 2 dose-response studies, insulin and/or TNF-alpha were coinfused. During infusion of insulin alone for 20 minutes, forearm glucose uptake increased by 220+/-44%. This increase was completely inhibited during coinfusion of TNF-alpha (started 10 min before insulin) with a more pronounced inhibition of glucose extraction than of blood flow. Furthermore, TNF-alpha inhibited the ACh forearm blood flow response (P<0.001), and this inhibition was larger during insulin infusion (P=0.01) but not further increased by NG-monomethyl-L-arginine acetate (P=0.2). Insulin potentiated the SNP response less than the ACh response and the effect of TNF-alpha was smaller (P<0.001); TNF-alpha had no effect on the SNP response without insulin infusion. Thus, TNF-alpha inhibition of the combined response to insulin and ACh was likely mediated through inhibition of NO production. CONCLUSIONS: These results support the concept that TNF-alpha could play a role in the development of insulin resistance in humans, both in muscle and in vascular tissue.

U2 - 10.1161/01.CIR.0000091406.72832.11

DO - 10.1161/01.CIR.0000091406.72832.11

M3 - Journal article

C2 - 14530204

VL - 108

SP - 1815

EP - 1821

JO - Circulation

JF - Circulation

SN - 0009-7322

IS - 15

ER -