Endothelial vasodilator function is related to low-density lipoprotein particle size and low-density lipoprotein vitamin E content in type 1 diabetes

J Am Coll Cardiol. 2000 Feb;35(2):292-9. doi: 10.1016/s0735-1097(99)00547-1.

Abstract

Objectives: We sought to determine whether endothelial vasodilator function (EVF) in patients with type 1 diabetes was related to low-density lipoprotein (LDL) particle size (LDLPS), LDL vitamin E content (LDLVE) or the susceptibility of LDL to oxidation (OxLDL).

Background: Impaired EVF is an early feature of diabetic vascular disease and may be related to oxidant stress. Although small, dense LDL and oxidized LDL are features of type 2 diabetes and predict the development of coronary artery disease, their role in type 1 diabetes is less clear.

Methods: Endothelium-dependent vasodilation was assessed in the brachial artery (flow-mediated vasodilation [FMD]) and in the forearm resistance circulation using venous occlusion plethysmography in response to graded doses of intrabrachial acetylcholine (ACh). Thirty-seven patients with type 1 diabetes mellitus (DM) and 45 matched controls underwent flow-mediated dilation, while a subset of 19 DM and 20 controls underwent plethysmography.

Results: Total, LDL and high-density lipoprotein cholesterol or triglycerides were not different in DM compared with controls, but LDLPS was smaller (25.6 +/- 0.06 vs. 26.1 +/- 0.1 nm, p < 0.05) and LDLVE was reduced (2.0 +/- 0.25 vs. 2.6 +/- 0.18 micromol/mmol LDL, p < 0.05). Oxidative susceptibility of LDL was not different. Flow-mediated vasodilation was impaired in DM compared with controls (3.6 +/- 0.6% vs. 7.1 +/- 0.5%, p < 0.005), as was the vasodilator response to ACh (p < 0.05). Flow-mediated vasodilation was directly related to LDLPS and LDLVE in both the entire study cohort and DM alone (p < 0.05), but not to other parameters of the standard lipid profile. Similarly, endothelium-dependent vasodilation in the resistance circulation was directly related to LDLPS and LDLVE, but not to OxLDL.

Conclusion: These results suggest, but do not prove, that LDL particle size and LDL vitamin E may be determinants of conduit and resistance vessel endothelial vasodilator function in type 1 diabetes. Further work will be required to prove cause and effect.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholine / administration & dosage
  • Adult
  • Biomarkers / blood
  • Blood Flow Velocity
  • Brachial Artery / diagnostic imaging
  • Brachial Artery / drug effects
  • Brachial Artery / physiopathology
  • Cholesterol, LDL / blood*
  • Diabetes Mellitus, Type 1 / blood
  • Diabetes Mellitus, Type 1 / physiopathology*
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / physiopathology*
  • Humans
  • Infusions, Intra-Arterial
  • Nitroglycerin / administration & dosage
  • Nitroprusside / administration & dosage
  • Oxidative Stress
  • Prognosis
  • Risk Factors
  • Ultrasonography
  • Vasodilation / drug effects
  • Vasodilation / physiology*
  • Vasodilator Agents / administration & dosage
  • Vitamin E / blood*

Substances

  • Biomarkers
  • Cholesterol, LDL
  • Vasodilator Agents
  • Vitamin E
  • Nitroprusside
  • Nitroglycerin
  • Acetylcholine