Human intestinal Caco-2 cell model to evaluate the absorption of 7-ketophytosterols and their effects on cholesterol transport

Abstract

7-Ketophytosterols are the major oxidation products of phytosterols in foods, which have been associated with atherosclerosis. However, their absorption mechanism remains unclear. The aim of our work was to investigate the absorption mechanism of 7-ketophytosterols and their effects on the cholesterol transport using Caco-2 cell model. The absorption percentage of 7-ketositosterol and 7-ketocampesterol was 1.16 %−1.68 % and 1.18 %−2.23 % respectively in the Caco-2 model, which is higher than that of their parent phytosterols, but lower than cholesterol-d7. The apparent permeability of 7-ketositosterol and 7-ketocampesterol at 30 μmol/L in the basolateral (BL)-to-apical (AP) direction were 0.42- and 0.55-fold of that in the AP-to-BL direction, indicating an active intake in the permeation mechanism of 7-ketophytosterols. Ezetimibe could significantly inhibit the transport of 7-ketophytosterols (P < 0.05), which means that their transport depends on niemann-pick c1-like 1 (NPC1L1) protein. The transport of cholesterol-d7 was significantly inhibited by 7-ketophytosterols (P < 0.05). Taken together, this study deepened our understanding of the absorption mechanism of common food-born 7-ketophytosterols and provides useful information on the inhibition of 7-ketophytosterols absorption.

Keywords

• 7-Ketophytosterols
• Absorption mechanism
• Cholesterol absorption
• Niemann-pick c1-like 1