INRA, UMR 1260 "Nutrition, Obesity and Risk of Thrombosis", F-13385 Marseille, France; INSERM, UMR U1062, F-13385 Marseille, France; Aix-Marseille University, F-13385 Marseille, France; Lesieur, Asnières-sur-Seine, France.
J Nutr Biochem. 2013 Oct;24(10):1751-7. doi: 10.1016/j.jnutbio.2013.03.004. Epub 2013 Jun 13.
We have recently shown that vitamin D3 (cholecalciferol) absorption is not a simple passive diffusion but involves cholesterol transporters. As free fatty acids (FAs) modulate cholesterol intestinal absorption and metabolism, we hypothesized that FAs may also interact with vitamin D absorption. Effects of FAs were evaluated at different levels of cholecalciferol intestinal absorption. First, the physicochemical properties of micelles formed with different FAs were analyzed. The micelles were then administered to human Caco-2 cells in culture to evaluate FA effects on (i) cholecalciferol uptake and basolateral efflux and (ii) the regulation of genes coding proteins involved in lipid absorption process. Micellar electric charge was correlated with both FA chain length and degree of unsaturation. Long-chain FAs at 500 μM in mixed micelles decreased cholecalciferol uptake in Caco-2 cells. This decrease was annihilated as soon as the long-chain FAs were mixed with other FAs. Oleic acid significantly improved cholecalciferol basolateral efflux compared to other FAs. These results were partly explained by a modulation of genes coding for lipid transport proteins such as Niemann-pick C1-like 1 and scavenger receptor class B type I. The data reported here show for the first time that FAs can interact with cholecalciferol intestinal absorption at different key steps of the absorption process. Cholecalciferol intestinal absorption may thus be optimized according to oil FA composition.
我们最近表明，维生素 D3（胆钙化醇）的吸收不是一个简单的被动扩散过程，而是涉及胆固醇转运蛋白。由于游离脂肪酸（FAs）调节胆固醇的肠道吸收和代谢，我们假设 FAs 也可能与维生素 D 的吸收相互作用。在胆钙化醇肠道吸收的不同水平评估了 FAs 的作用。首先，分析了不同 FAs 形成的胶束的物理化学性质。然后将这些胶束施用于体外培养的人 Caco-2 细胞，以评估 FA 对（i）胆钙化醇摄取和基底外侧流出以及（ii）编码参与脂质吸收过程的蛋白质的基因的调节的影响。胶束的电荷量与 FA 链长和不饱和程度都相关。在混合胶束中，500μM 的长链 FAs 降低了 Caco-2 细胞中的胆钙化醇摄取。只要长链 FAs 与其他 FAs 混合，这种降低就会消失。与其他 FAs 相比，油酸显著增加了胆钙化醇的基底外侧流出。这些结果部分解释了编码脂质转运蛋白的基因的调节，例如尼曼-匹克 C1 样 1 和清道夫受体 B 型 I。这里报道的数据首次表明，FAs 可以在吸收过程的不同关键步骤与胆钙化醇的肠道吸收相互作用。因此，胆钙化醇的肠道吸收可以根据油 FA 的组成进行优化。
