Intermittent high glucose enhances apoptosis in human umbilical vein endothelial cells in culture

• DOI: 10.1152/ajpendo.2001.281.5.e924
• Publication Date: 2017-12-22T19:57:52Z
• Authors: A. Risso; F. Mercuri; L. Quagliaro; G. Damante; A. Ceriello
• Keywords: Electrophoresis, Agar Gel; Umbilical Veins; Cell Survival; Blotting, Western; Cell Cycle; Apoptosis; DNA Fragmentation; 03 medical and health sciences; Glucose; 0302 clinical medicine; Proto-Oncogene Proteins c-bcl-2; Proto-Oncogene Proteins; Humans; Endothelium, Vascular; Cells, Cultured; bcl-2-Associated X Protein

To explore the effect of fluctuating glucose on endothelial cells, human umbilical vein endothelial cells were incubated for 14 days in media containing different glucose concentrations: 5 mmol/l, 20 mmol/l, or a daily alternating 5 or 20 mmol/l glucose. Apoptosis was studied by different methods: viability assay, cell cycle analysis, DNA fragmentation, and morphological analysis. Furthermore, the levels of Bcl-2 and Bax, well known proteins involved in apoptosis, were evaluated. Stable high glucose induced apoptosis in human umbilical vein endothelial cells, a phenomenon accompanied by a significant decrease of Bcl-2 and a simultaneous increase of Bax expression. However, apoptosis was enhanced in human umbilical vein endothelial cells exposed to intermittent, rather than constant, high glucose concentration. In this condition, Bcl-2 was not detectable, whereas Bax expression was significantly enhanced. These findings suggest that variability in glycemic control could be more deleterious to endothelial cells than a constant high concentration of glucose.