Figure 1. Leukocytes from diabetic patients induce death of human retinal endothelial cells (HRECs). A: Comparison of endothelial death due to direct contact between leukocytes and human retinal endothelial cells (HRECs) and release of soluble factors from leukocytes are shown. Representative dot plots from cytometrically analyzed cells cultured in various coculture systems are shown. L, low-glucose medium; H, high-glucose medium; N, neutrophils from nondiabetic patients; D, neutrophils from diabetic patients. B: Inhibiting contact of leukocytes with HRECs using antibodies against intercellular adhesion molecule-1 (ICAM-1) or integrin beta-2 (CD18) inhibits endothelial death in the H+D coculture system. C: Graphical summary of HREC apoptosis from data in 1A is shown (n=10). * indicates that the effect of high glucose and neutrophils from diabetic patients on HREC apoptosis was significant (p<0.001). ^† indicates a significant decrease in the apoptosis rate in the transwell system versus direct cell–cell contact in the L+D group (p<0.05), and ^‡ indicates significantly less apoptosis in the transwell system versus direct cell–cell contact in the H+D group (p<0.05). D: Graphical summary of HREC apoptosis from data in 1B (n=3). * indicates a significant difference (p<0.001) compared to the non-treated group. Error bars represent SD.