Insulin inhibits the expression of intercellular adhesion molecule-1 by human aortic endothelial cells through stimulation of nitric oxide

J Clin Endocrinol Metab. 2000 Jul;85(7):2572-5. doi: 10.1210/jcem.85.7.6677.

Abstract

Intercellular adhesion molecule-1 (ICAM-1) is expressed by endothelial and other cell types and participates in inflammation and atherosclerosis. It serves as a ligand for leukocyte function-associated antigen-1 on leukocytes and is partially responsible for the adhesion of lymphocytes, granulocytes, and monocytes to cytokine-stimulated endothelial cells and the subsequent transendothelial migration. Its expression on endothelial cells is increased in inflammation and atherosclerosis. As it has been suggested that insulin and hyperinsulinemia may have a role in atherogenesis, we have now investigated whether insulin has an effect on the expression of ICAM-1 on human aortic endothelial cells (HAEC). HAEC were prepared from human aortas by collagenase digestion and were grown in culture. Insulin (100 and 1000 microU/mL) caused a decrease in the expression of ICAM-1 (messenger ribonucleic acid and protein) by these cells in a dose-dependent manner after incubation for 2 days. This decrease was associated with a concomitant increase in endothelial nitric oxide synthase (NOS) expression also induced by insulin. To examine whether the insulin-induced inhibition of ICAM-1 was mediated by nitric oxide (NO) from increased endothelial NOS, HAEC were treated with N(omega)-nitro-L-arginine, a NOS inhibitor. N(omega)-Nitro-L-arginine inhibited the insulin-induced decrease in ICAM-1 expression in HAEC at the messenger ribonucleic acid and protein levels. Thus, the inhibitory effect of insulin on ICAM-1 expression is mediated by NO. We conclude that insulin reduces the expression of the proinflammatory adhesion molecule ICAM-1 through an increase in the expression of NOS and NO generation and that insulin may have a potential antiinflammatory and antiatherosclerotic effect rather than a proatherosclerotic effect.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aorta / cytology
  • Aorta / drug effects
  • Aorta / metabolism
  • Blotting, Western
  • Cell Separation
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / metabolism*
  • Enzyme Inhibitors
  • Humans
  • Hypoglycemic Agents / pharmacology*
  • Insulin / pharmacology*
  • Intercellular Adhesion Molecule-1 / biosynthesis*
  • Nitric Oxide / biosynthesis
  • Nitric Oxide / physiology*
  • Nitric Oxide Synthase / antagonists & inhibitors
  • Nitric Oxide Synthase / biosynthesis
  • Nitric Oxide Synthase Type III
  • Nitroarginine / pharmacology
  • Reverse Transcriptase Polymerase Chain Reaction

Substances

  • Enzyme Inhibitors
  • Hypoglycemic Agents
  • Insulin
  • Intercellular Adhesion Molecule-1
  • Nitroarginine
  • Nitric Oxide
  • NOS3 protein, human
  • Nitric Oxide Synthase
  • Nitric Oxide Synthase Type III