Telomerase activity and telomere length distribution in vascular endothelial cells in a short-term culture under the presence of hydrogen peroxide

Aim: The aim of this study was to assess the biological effects of oxidative stress on human vascular endothelial cells. Methods: The telomeric changes and the alterations of the expression of telomere-associated proteins in human umbilical venous endothelial cells (HUVEC) cultured in the presence of hydrogen peroxide (H₂O₂) were analyzed. Results: During the culture, the cell growth rate decreased, whereas the telomerase activity of the surviving cells increased. As the H₂O₂ level increased, long telomeres decreased proportionally, thus resulting in a telomere length distribution that was rich in short telomeres. These observations suggested that H₂O₂-affected endothelial cells bear telomeric features similar to those of aged cells. In contrast, the expression of telomere-associated proteins, TRF1 and TRF2, showed different changes. TRF1 increased in relation to H₂O₂ concentration, whereas TRF2 showed no significant change. The surviving cells exposed to H₂O₂ showed a H₂O₂-dose dependent increase in telomerase activity, whereas the telomere protein and RNA components were only elevated in low concentrations of H₂O₂. Conclusions: The increase in telomerase activity and TRF1 protein expression of vascular endothelial cell might show an aspect of cellular protective reaction against oxygen stress. Geriatr Gerontol Int 2013; 13: 774-782.