AbstractThe world health organization defines ageing as a natural, inevitable and multifactorial process that occurs at genetic, molecular, cellular, organ and system levels. Among the biological structures that are affected by ageing, endothelial cells are of utmost importance due to their role in regulating blood flow and vascular hemostasis. In vitro cultivation of endothelial cells over several passages leads to morphological and functional changes which has been described as replicative senescence. However, it is unclear whether these changes in vitro reflect human cellular ageing in vivo. A recent study analyzed freshly isolated endothelial cells, which were removed from vessels via J-wires, and showed that the expression of senescence markers p53, p16 and p21 was increased in endothelial cells from aged donors . Moreover, it was observed that tumors in the later stage of life (>80 years) grow slower suggesting that cell growth is decelerated with increasing age. However, clear evidence for this is missing.