Expression of intercellular adhesion molecules 1 (ICAM-1) via an osmotic effect in human umbilical vein endothelial cells exposed to high glucose medium

To clarify the etiology of accelerated atherosclerosis in patients with diabetes mellitus, we measured expression of intercellular adhesion molecule 1 (ICAM-1), vascular cellular adhesion molecule 1 (VCAM-1), and E-selectin on the cell surface by enzyme-linked immunosorbent assay and ICAM-1 mRNA content in human umbilical vein endothelial cells exposed to 5.5 mM glucose (NG), 33 mM glucose (HG), or 27.5 mM mannitol plus 5.5 mM glucose (HM). 1) Cell-surface ICAM-1 expression in HG and HM cells was maximally increased by 37% and 32% (P < 0.01), respectively. This effect was dependent on glucose concentration in the medium and was found as early as 24 h and maintained until 6 days after exposing cells to HG. However, neither VCAM-1 nor E-selectin expression were affected by HG conditions. 2) Both HG and HM induced increased mRNA content between 6 and 12 h after the stimulation. 3) Adhesion of THP-1 cells to endothelial cells exposed to HG and HM was increased, when compared to NG conditions. These results indicate that osmotic effects can induce increased mRNA and cell-surface expression of ICAM-1 via an as yet unknown mechanism.