Lycopene Absorption in Human Intestinal Cells and in Mice Involves Scavenger Receptor Class B Type I but Not Niemann-Pick C1-Like 11,2

Cholesterol membrane transporters (scavenger receptor class B type I (SR-BI) and (cluster determinant 36) are involved in intestinaluptakeofluteinand b-carotene,2ofthe3maincarotenoidsofthehumandiet.Theaimofthisworkwastherefore to determine whether SR-BI and NPC1L1 (Niemann-Pick C1-like 1), another cholesterol transporter, are implicated in absorption of lycopene, the 3rd main carotenoid of the human diet. Anti-human SR-BI antibody and block lipid transport 1 (BLT1) (a chemical inhibitor of lipid transport by SR-BI) impaired up to 60% (all-E) and (5Z)-lycopene uptake (P , 0.05) by Caco-2 cell monolayers, which were used as a model of human intestinal epithelium. The involvement of SR-BI in lycopene absorption in vivo was then verified by comparing plasma lycopene concentrations in wild-type and SR-BI transgenic mice that were fed a diet enriched with 0.25 g/kg (all-E)-lycopene for 1 mo. Plasma lycopene concentrations were ;10-fold higher(P ,0.001)inmiceoverexpressingSR-BIintheintestinethaninwild-typemice,confirmingtheinvolvementofSR-BI in lycopene absorption. Further experiments showed that (all-E)-lycopene did not affect SR-BI mRNA levels in Caco-2 cells or mouse intestine.In contrastto SR-BI, neitheranti-humanNPC1L1antibodynor ezetimibe,used as inhibitorsof lycopene uptake via NPC1L1, significantly impaired (all-E )o r (5Z)-lycopene uptake by Caco-2 monolayers. Thus, the present data show that lycopene absorption is, at least in part, mediated by SR-BI but not by NPC1L1. J. Nutr. 138: 1432-1436, 2008.