Importance of physiological oxygen levels for endothelial redox signaling using Hyper 7

Cellular redox status is tightly linked to ambient oxygen levels. Endothelial cells (EC) in vivo are exposed to O2 levels between 3- 13 kPa, yet the majority in vitro studies maintain EC under atmospheric O2 levels (~18 O2). Under 18 kPa O2, EC are exposed to hyperoxia, leading to persistent upregulation of NRF2 regulated antioxidant defences. Exposure of EC to physiological O2 levels for at least 5 days attenuates NRF2-regulated antioxidant gene expression in the absence of HIF-1a stabilisation.