Evaluation of endothelial cell culture as a model system of vascular ageing

The purpose of this study was to evaluate the relevance of long-term endothelial cell culture as a model system of vascular ageing. Micro- and macrovascular endothelial cells were serially passaged until replicative senescence and their ability to form tube-like structures when cultured on Matrigel was assessed throughout their lifespan. For both cell types low passage cultures adopted a homogeneous cobblestone morphology, while senescent cultures were extremely heterogeneous. Furthermore, both cell types showed a reduction in tube formation ability with in vitro ageing, which is in accordance with the reduction in angiogenic potential observed with ageing in vivo. Examination of senescence associated β-galactosidase activity revealed an increased activity in cells forming tubes as compared to cells cultured on plastic, which could be attributed to an increased lysosomal content of cells undergoing tube formation. As this increased senescence associated β-galactosidase activity was unrelated to the replicative age of the cells, senescence associated β-galactosidase activity may not be a relevant senescence marker for differentiating endothelial cells. The age-related reduction in tube formation ability suggested that long-term culture of endothelial cells may be a valid model system of vascular ageing, which makes it an ideal platform for high throughput screening of compounds influencing angiogenesis.