In vitro, tenilsetam inhibited endothelial proliferation at lower doses, while inducing apoptosis at high doses.?Leucocyte adhesion was only inhibited at high doses.?Sprouting angiogenesis of bovine retinal endothelial cells was promoted at lower doses (<?or = 10 mM).?At micromolar concentrations, endothelial VEGF expression was upregulated by 100%.?Long-term treatment with the AGE-inhibitor and iron-chelating compound tenilsetam inhibits the formation of acellular capillaries without correcting pericyte loss.?The compound has dose-dependent effects on endothelial cell function.