The Anti-apoptotic Effect of Adrenomedullin on Vascular Endothelial Cells in Radiocontrast Media-induced Apoptosis

Purpose : Because vascular endothelial cells play a pivotal role in the vascular diseases, damage of vascular endothelial cells lead to progression of vascular disease. Apoptotic damage of cells is an important mechanism in vascular disease. Therefore, several growth factors that have antiapoptotic effect may have a protective role in maintaining a cell function in apoptotic cell injury. In this study, we examined the effects of adrenomedullin on apoptosis in iopromide-induced endothelial cell injury. Methods : Human umbilical vein endothelial cells were incubated with nonionic radiocontrast agent, iopromide and/or adrenomedullin. Apoptosis was assessed quantitatively using FACScan after annexin V-FITC and propidium iodide staining, and by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) stain. Signaling pathway was evaluated by Western blot analysis of phospho-Akt and Akt. Results : Iopromide-induced apoptosis in human umbilical vein endothelial cells was increased in a dose-dependent manner. Adrenomedullin prevented iopromide-induced apoptosis in human umbilical vein endothelial cells in a dose dependent manner. Wortmannin, phosphatidylinositol 3-kinase inhibitor, decrease the adrenomedullin-induced antiapoptotic effect. Conclusion : These results suggest that adrenomedullin protects vascular endothelial cells from iopromide-induced apoptosis by regulating the activity of Akt.