Investigation of autophagy in human umbilical cord venous endothelial cells under hyperglycemic conditions

Objective: Hyperglycemia is a condition characterized by the presence of excessive amounts of glucose in the blood. Endothelial cells, which are the building blocks of vascular structures, are highly sensitive to hyperglycemia. Autophagy is a mechanism that regulates cell survival and energy metabolism under starvation and stress conditions. This study aims to investigate the autophagy mechanism in human umbilical cord venous endothelial cells (HUVEC) under hyperglycemic conditions. Method: Human umbilical cord venous endothelial cells were isolated from the veins of the umbilical cord and incubated for 24 hours, 48 hours or 72 hours in special media with different glucose concentrations. At the end of these periods, the cells were prepared for Western Blot and PCR analysis and the autophagy markers LC3, p62 and Beclin-1 were compared between the groups. Results: The amount of LC3 in the 24-hour hyperglycemic groups was significantly reduced compared to the control. The amount of LC3 increased significantly in the 48- hour hyperglycemic groups compared to the control. The amounts of Beclin-1 and LC3 in the 72 hour hyperglycemic groups increased significantly compared to the control. On the other hand, the amount of p62 decreased significantly in the 72-hour hyperglycemic groups compared to the control. Conclusion: The decrease in autophagy in cells due to hyperglycemia in the first 24 hours indicates that autophagy is inhibited by glucose. However, an increase in autophagy was detected at 48 and 72 hours. The increase in autophagy is due to the prolonged exposure to the hyperglycemic environment. As a result, autophagy mechanism in HUVEC cells varies according to time and amount of glucose to which it is exposed. Key words: hyperglycemia, human umbilical cord venous endothelial cells, autophagy