Garrett D A, Failla M L, Sarama R J, Craft N
Graduate Program in Nutrition, The University of North Carolina at Greensboro, Greensboro, NC, USA.
J Nutr Biochem. 1999 Oct;10(10):573-81. doi: 10.1016/s0955-2863(99)00044-3.
Despite the interest in the diverse roles of dietary carotenoids in human health, little is known about the transfer of these plant pigments from foods to micelles during digestion and their subsequent transfer across the intestinal epithelium. We conducted this study to characterize the intestinal uptake of micellarized carotenoids using monolayers of differentiated Caco-2 human intestinal cells. Crystalline beta-carotene (BC) and lutein (LUT), solubilized in mixed micelles for delivery to cells, were stable in a tissue culture environment for 20 hours. Cellular accumulation of micellar BC and LUT was proportional to the media content of carotenoids at </=2 micromol/L and the length of exposure. Cellular accumulation of BC routinely exceeded LUT and was due in part to the enhanced efflux or possible metabolism of LUT. Cellular BC content increased in a curvilinear manner when cultures were incubated in micellar medium containing 2 to 27 micromol/L BC prepared from water miscible beadlets; cellular BC content was maximum when medium BC was >/=18 micromol/L. There was no indication that high levels of BC in medium or within cells adversely affected micellar LUT accumulation. These data support the use of the Caco-2 human cell line as a model for studying the intestinal uptake, absorption, and possible interactions of dietary carotenoids.
尽管膳食类胡萝卜素在人类健康中的多种作用备受关注，但对于这些植物色素在消化过程中从食物转移到微胶粒以及随后穿过肠上皮细胞的过程却知之甚少。我们开展这项研究，旨在利用分化的Caco-2人肠细胞单层来表征微胶粒化类胡萝卜素的肠道摄取情况。溶解于混合微胶粒中以便递送至细胞的结晶β-胡萝卜素（BC）和叶黄素（LUT），在组织培养环境中20小时内保持稳定。微胶粒化BC和LUT的细胞积累与类胡萝卜素在≤2 μmol/L时的培养基含量以及暴露时间成正比。BC的细胞积累通常超过LUT，部分原因是LUT的外排增强或可能发生了代谢。当培养物在含有由水溶性小丸制备的2至27 μmol/L BC的微胶粒培养基中孵育时，细胞内BC含量呈曲线增加；当培养基中BC≥18 μmol/L时，细胞内BC含量达到最大值。没有迹象表明培养基或细胞内的高浓度BC会对微胶粒化LUT的积累产生不利影响。这些数据支持将Caco-2人细胞系用作研究膳食类胡萝卜素的肠道摄取、吸收及可能相互作用的模型。
