Vitamin D intestinal absorption is not a simple passive diffusion: Evidences for involvement of cholesterol transporters.

Abstract : Scope: It is assumed that vitamin D is absorbed by passive diffusion. However, since cholecalciferol (vitamin D(3) ) and cholesterol display similar structures, we hypothesized that common absorption pathways may exist. Methods and results: Cholecalciferol apical transport was first examined in human Caco-2 and transfected Human embryonic kidney (HEK) cells. Cholecalciferol uptake was then valuated ex vivo and in vivo, using either wild-type mice, mice overexpressing Scavenger Receptor class B type I (SR-BI) at the intestinal level or mice treated or not with ezetimibe. Cholecalciferol uptake was concentration-, temperature- and direction-dependent, and was significantly impaired by a co-incubation with cholesterol or tocopherol in Caco-2 cells. Moreover Block Lipid Transport-1 (SR-BI inhibitor) and ezetimibe glucuronide (Niemann-Pick C1 Like 1 inhibitor) significantly decreased cholecalciferol transport. Transfection of HEK cells with SR-BI, Cluster Determinant 36 and Niemann-Pick C1 Like 1 significantly enhanced vitamin D uptake, which was significantly decreased by the addition of Block Lipid Transport-1, sulfo-N-succinimidyl oleate (Cluster Determinant 36 inhibitor) or ezetimibe glucuronide, respectively. Similar results were obtained in mouse intestinal explants. In vivo, cholecalciferol uptake in proximal intestinal fragments was 60% higher in mice overexpressing SR-BI than in wild-type mice (p<0.05), while ezetimibe effect remained non-significant. Conclusion: These data show for the first time that vitamin D intestinal absorption is not passive only but involves, at least partly, some cholesterol transporters.
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Molecular Nutrition and Food Research, Wiley-VCH Verlag, 2011, 55 (5), pp.691-702. 〈10.1002/mnfr.201000553〉
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Soumis le : lundi 30 mai 2011 - 17:52:30
Dernière modification le : mardi 11 septembre 2018 - 15:18:46

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Emmanuelle Reboul, Aurélie Goncalves, Christine Comera, Romain Bott, Marion Nowicki, et al.. Vitamin D intestinal absorption is not a simple passive diffusion: Evidences for involvement of cholesterol transporters.. Molecular Nutrition and Food Research, Wiley-VCH Verlag, 2011, 55 (5), pp.691-702. 〈10.1002/mnfr.201000553〉. 〈inserm-00597005〉

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