[Elimination of cholesterol in human endothelial cells].
OBJECTIVE
To investigate what role the endothelial cell interfacing with blood components to play in cholesterol metabolism.


METHODS
Isotopelabeling technique, Gas Chromatography/Mass Spectrometry and Western blotting were used to measure the presence of 27-oxygenated cholesterol in medium and the presence of sterol 27-hydroxylase in endothelium.


RESULTS
When human endothelial cells were cultured in a medium containing fetal calf serum, there was a significant accumulation of 27-hydroxycholesterol and 3 beta-hydroxy-5-cholesteneic acid, products of cholesterol metabolism, in the medium. The rate of formation of these products almost increased linearly with time of cultivation. After addition of 100 micrograms of extraneous cholesterol to the medium, the accumulation of 27-hydroxy-cholesterol and 3 beta-hydroxy-5-cholesteneic acid increased significantly. Addition of more cholesterol did not further increase the formation of 27-hydroxy-cholesterol and caused a decrease in the formation of 3 beta-hydroxy-5 cholesteneic acid. The presence of sterol-27-hydroxylase in the endothelium was demonstrated by Western blotting.


CONCLUSIONS
Cultured human endothelium from umbilical veins are able to convert exogenous cholesterol into 27-hydroxy-cholesterol and 3 beta-hydroxy-5-cholesteneic acid. Furthermore, the cells are able to transport these products from the cells into the medium.
Institute of Microcirculation, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing.
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Xiu
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Duan
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Li
D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D006888:Hydroxycholesterols / Q000378:metabolism*; D014471:Umbilical Veins / Q000166:cytology
D006888:Hydroxycholesterols; C076996:27-hydroxycholesterol; D002784:Cholesterol