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The aim of the study was to assess and compare the effect of oxidized cholesterols (7-ketocholesterol and 25-hydroxycholesterol) on the barrier properties of human primary aortic endothelium (HAEC) and intestinal epithelium Caco-2 cells using a real-time cell electric impedance sensing system (RTCA-DP)
. HAEC and Caco-2 cells were stimulated with 7-ketocholesterol and 25-hydroxycholesterol by the RTCA-DP system. Apoptosis was assessed by flow cytometry and cell monolayer morphology was assessed under a light microscope. 
7-ketocholesterol decreased impedance (nCI) in both the endothelium and epithelium. However, the decrease was more profound in the endothelium
. Similarly, although 25-hydroxycholesterol decreased nCI in both the endothelium and epithelium, the effect was weaker than that of 7-ketocholesterol, which caused extensive damage to the endothelial monolayer, while 25-hydroxycholesterol caused partial damage and did not affect the epithelial monolayer.
7-ketocholesterol, but not 25-hydroxycholesterol, increased endothelial cell apoptosis and decreased the viability of endothelial cells
. However, 7-ketocholesterol and 25-hydroxycholesterol decreased epithelial cell apoptosis and increased viability. 
Oxidized cholesterols destroy the HAEC, but not the Caco-2 epithelial barrier, via cell apoptosis dependent on the site of oxidation
. Damage to the endothelium by oxidized cholesterol may disrupt local homeostasis and provide open access to inner parts of the vascular wall for lipids, other peripheral blood-derived agents, and immune cells, leading to inflammation and atherogenesis.