ICAM-1 but not E-selectin is upregulated by ionizing radiation in human umbilical vein endothelial cells and human microvascular endothelial cells

We have investigated the expression of E-selectin and ICAM-1 on human umbilical vein endothelial cells (HUVEC) and human microvascular endothelial cells (HMEC) at 5 hr, 24 hr, 48 hr and 72 hr post-irradiation. Cells were irradiated (IR) with a single dose of 10 Gy and expression of molecules quantified by flow cytometric analysis. Preliminary results indicate that ICAM-1 is upregulated at 48 hr. Post-IR in both cell types. We did not observe upregulation of E-selectin post-IR. Consistent with this latter finding, in vitro parallel plate flow chamber assays (shear stress of 0.5- 2.0 dynes/cm/sup 2/) revealed a lack of HL-60 rolling on HUVECs and HMECs monolayers 5 hr. post-IR. Thus, our finding suggest that, in response to radiation ICAM-1 is upregulated, but not E-selectin.