Hyperglycemia rapidly suppresses flow-mediated endothelium-dependent vasodilation of brachial artery

J Am Coll Cardiol. 1999 Jul;34(1):146-54. doi: 10.1016/s0735-1097(99)00168-0.


Objectives: We examined whether endothelial dysfunction occurs when acute hyperglycemia is induced by oral glucose loading.

Background: Endothelial dysfunction has been shown to occur in patients with diabetes mellitus (DM), and chronic hyperglycemia is implicated as a cause of endothelial dysfunction. However, in many patients with Type 2 DM and in those with impaired glucose tolerance (IGT), fasting blood glucose may be within normal limits, and hyperglycemia occurred only post-prandially.

Methods: With ultrasound technique, we measured flow-mediated endothelium-dependent vasodilation during oral glucose tolerance test in 58 subjects: (17 patients with normal glucose tolerance [NGT], 24 with IGT, and 17 with type 2 DM). In addition, we measured the levels of thiobarbituric acid reactive substances (TBARS) and nitrite/nitrate.

Results: Flow-mediated vasodilation decreased after glucose loading (NGT: 7.53+/-0.40, 4.24+/-0.28 and 6.35+/-0.40, in fasting, at 1- and 2-h, respectively, IGT: 6.50+/-0.48, 1.40+/-0.41** and 4.00+/-0.47*, respectively; DM: 4.77+/-0.37, 1.35+/-0.38** and 1.29+/-0.29%**, respectively; *p < 0.01 vs. fasting, **p < 0.005 vs. fasting). The TBARS concentration increased in parallel with plasma glucose level in each group (NGT: 1.43+/-0.07, 2.03+/-0.12 and 1.80+/-0.12, respectively; IGT: 1.65+/-0.11, 2.46+/-0.12** and 1.94+/-0.08*, respectively; DM: 1.73+/-0.07, 2.34+/-0.08** and 2.47+/-0.09** nmol/ml, respectively; *p < 0.05 vs. fasting, **p < 0.01 vs. fasting). Glucose loading did not change nitrite/nitrate concentration in any of the groups.

Conclusions: Hyperglycemia in response to oral glucose loading rapidly suppresses endothelium-dependent vasodilation, probably through increased production of oxygen-derived free radicals. These findings strongly suggest that prolonged and repeated post-prandial hyperglycemia may play an important role in the development and progression of atherosclerosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Brachial Artery / physiology*
  • Diabetes Mellitus / blood
  • Diabetes Mellitus / physiopathology*
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / physiopathology
  • Endothelium, Vascular / physiology*
  • Female
  • Glucose Tolerance Test
  • Humans
  • Hyperglycemia / physiopathology*
  • Male
  • Middle Aged
  • Regional Blood Flow
  • Vasodilation / physiology*