title: Elevation in blood flow and shear rate prevents hyperglycemia-induced endothelial dysfunction in healthy subjects and those with type 2 diabetes.
abstract: Hyperglycemia, commonly present after a meal, causes transient impairment in endothelial function. We examined whether increases in blood flow (BF) protect against the hyperglycemia-mediated decrease in endothelial function in healthy subjects and patients with type 2 diabetes mellitus (T2DM). Ten healthy subjects and 10 age- and sex-matched patients with T2DM underwent simultaneous bilateral assessment of brachial artery endothelial function by means of flow-mediated dilation (FMD) using high-resolution echo-Doppler. FMD was examined before and 60, 120, and 150 min after a 75-g oral glucose challenge. We unilaterally manipulated BF by heating one arm between minute 30 and minute 60. Oral glucose administration caused a statistically significant, transient increase in blood glucose in both groups (P < 0.001). Forearm skin temperature, brachial artery BF, and shear rate significantly increased in the heated arm (P < 0.001), and to a greater extent compared with the nonheated arm in both groups (interaction effect P < 0.001). The glucose load caused a transient decrease in FMD% (P < 0.05), whereas heating significantly prevented the decline (interaction effect P < 0.01). Also, when correcting for changes in diameter and shear rate, we found that the hyperglycemia-induced decrease in FMD can be prevented by local heating (P < 0.05). These effects on FMD were observed in both groups. Our data indicate that nonmetabolically driven elevation in BF and shear rate can similarly prevent the hyperglycemia-induced decline in conduit artery endothelial function in healthy volunteers and in patients with type 2 diabetes. Additional research is warranted to confirm that other interventions that increase BF and shear rate equally protect the endothelium when challenged by hyperglycemia.
authors.affiliation: Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands; Unilever R&D Vlaardingen, The Netherlands; and.
authors.forename: Arno
authors.initials: A
authors.lastname: Greyling
authors.affiliation: Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands;
authors.forename: Tim H A
authors.initials: TH
authors.lastname: Schreuder
authors.affiliation: Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands;
authors.forename: Thijs
authors.initials: T
authors.lastname: Landman
authors.affiliation: Unilever R&D Vlaardingen, The Netherlands; and.
authors.forename: Richard
authors.initials: R
authors.lastname: Draijer
authors.affiliation: Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands;
authors.forename: Rebecca J H M
authors.initials: RJ
authors.lastname: Verheggen
authors.affiliation: Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands;
authors.forename: Maria T E
authors.initials: MT
authors.lastname: Hopman
authors.affiliation: Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands; Research Institute for Sports and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom Dick.Thijssen@radboudumc.nl.
authors.forename: Dick H J
authors.initials: DH
authors.lastname: Thijssen
mesh_terms: D001786:Blood Glucose / Q000502:physiology; D001916:Brachial Artery / Q000503:physiopathology; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000378:metabolism / Q000503:physiopathology*; D005542:Forearm / Q000503:physiopathology; D005947:Glucose / Q000378:metabolism; D064368:Healthy Volunteers; D006801:Humans; D006943:Hyperglycemia / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow / Q000502:physiology*; D013314:Stress, Mechanical; D014652:Vascular Diseases / Q000378:metabolism / Q000503:physiopathology*; D014664:Vasodilation / Q000502:physiology
chemical_list: D001786:Blood Glucose; D005947:Glucose
keywords: blood flow; cardiovascular risk; endothelial function; flow-mediated dilation; hyperglycemia; shear rate