High glucose exacerbates neutrophil adhesion to human retinal endothelial cells

Leukocyte accumulation in the retina is thought to play a key role in the early stage of diabetic retinopathy. Leukocyte-endothelial adhesion is important for leukostasis, and high glucose levels may influence it. However, few studies have demonstrated leukocyte-endothelial adhesion using cultured human retinal endothelial cells (HRECs) after high glucose exposure. We report herein the results of neutrophil-endothelial adhesion assay after high glucose exposure. A high concentration of glucose (46.1 mM for 48 h) significantly increased neutrophil adhesion to HRECs as compared to controls. This phenomenon was blocked by PKC inhibitor and anti-intercellular adhesion molecule-1 antibody. Hyperosmolarity did not affect neutrophil-endothelial adhesion. These results suggested that glucose enhances neutrophil adhesion to HRECs through surface expression of ICAM-1 via activation of the PKC pathway.