Increased adhesion of neutrophils to retinal vascular endothelial cells exposed to hyperosmolarity


Journal Article

Recent studies suggest that leukocytes may contribute to capillary occlusion and endothelial cell injury in diabetic retinopathy. The present study is an attempt to determine whether high glucose concentration/hyperosmolar conditions would increase neutrophil adhesion to retinal endothelial cell monolayers. Confluent monolayers of bovine retinal endothelial cells were incubated for 24 hr in 96-well microtiter plates in 5.5, 20, 50 or 100 mM glucose using 20, 50 or 100 mM mannitol as osmotic controls. After 24 hr the cells were observed by phase microscopy, washed, and then incubated with isolated human neutrophils for 20 min. Non-adherent neutrophils were washed from the monolayers, and the number of adherent neutrophils was determined using an Elisa assay for neutrophil elastase. Adhesion of neutrophils to confluent monolayers of human umbilical vein and bovine aortic endothelial cells at all levels of glucose were assayed in a similar fashion for comparison. Neutrophil adherence to bovine retinal endothelial cells was significantly increased (P < 0.05, n = 8; paired t- test) at all elevated glucose concentrations compared with adherence at control (5.5 mM) glucose concentration. The effect was also concentration dependent with 20, 50 and 100 mM glucose resulting in 35, 57 and 70% increases respectively over controls. However, mannitol at equal concentrations produced similar increases in neutrophil adherence, indicating that the increases in adhesion caused by elevated glucose concentration were due to hyperosmolarity and not some special effect of glucose. Neutrophil adherence was not significantly increased to human umbilical vein endothelial cells, at any of the elevated concentrations of glucose. Neutrophil adherence to bovine aortic endothelial cells was significantly higher for 50 and 100 mM glucose compared to control (13% and 25% increases in adhesion, respectively). These data support the hypothesis that increased adhesion of neutrophils to retinal endothelial cells exposed to a hyperosmotic environment (as is present in diabetes) may play a significant role in the pathogenesis of diabetic retinopathy.

Full Text

Duke Authors

Cited Authors

  • Bullard, SR; Hatchell, DL; Cohen, HJ; Rao, KMK

Published Date

  • January 1, 1994

Published In

Volume / Issue

  • 58 / 6

Start / End Page

  • 641 - 647

International Standard Serial Number (ISSN)

  • 0014-4835

Digital Object Identifier (DOI)

  • 10.1006/exer.1994.1061

Citation Source

  • Scopus