Bartolini Desirée, Marinelli Rita, Giusepponi Danilo, Galarini Roberta, Barola Carolina, Stabile Anna Maria, Sebastiani Bartolomeo, Paoletti Fabiola, Betti Michele, Rende Mario, Galli Francesco
Department of Pharmaceutical Sciences, University of Perugia, 06126 Perugia, Italy.
Department of Medicine, University of Perugia, 06126 Perugia, Italy.
Antioxidants (Basel). 2021 Jan 25;10(2):173. doi: 10.3390/antiox10020173.
The metabolism of α-tocopherol (α-TOH, vitamin E) shows marked interindividual variability, which may influence the response to nutritional and therapeutic interventions with this vitamin. Recently, new metabolomics protocols have fostered the possibility to explore such variability for the different metabolites of α-TOH so far identified in human blood, i.e., the "vitamin E metabolome", some of which have been reported to promote important biological functions. Such advances prompt the definition of reference values and degree of interindividual variability for these metabolites at different levels of α-TOH intake. To this end, a one-week oral administration protocol with 800 U RRR-α-TOH/day was performed in 17 healthy volunteers, and α-TOH metabolites were measured in plasma before and at the end of the intervention utilizing a recently validated LC-MS/MS procedure; the expression of two target genes of α-TOH with possible a role in the metabolism and function of this vitamin, namely pregnane X receptor (PXR) and the isoform 4F2 of cytochrome P450 (CYP4F2) was assessed by immunoblot in peripheral blood leukocytes. The levels of enzymatic metabolites showed marked interindividual variability that characteristically increased upon supplementation. With the exception of α-CEHC (carboxy-ethyl-hydroxychroman) and the long-chain metabolites M1 and α-13'OH, such variability was found to interfere with the possibility to utilize them as sensitive indicators of α-TOH intake. On the contrary, the free radical-derived metabolite α-tocopheryl quinone significantly correlated with the post-supplementation levels of α-TOH. The supplementation stimulated PXR, but not CYP4F2, expression of leucocytes, and significant correlations were observed between the baseline levels of α-TOH and both the baseline and post-supplementation levels of PXR. These findings provide original analytical and molecular information regarding the human metabolism of α-TOH and its intrinsic variability, which is worth considering in future nutrigenomics and interventions studies.
α-生育酚(α-TOH,维生素E)的代谢存在显著的个体间差异,这可能会影响对该维生素进行营养和治疗干预的反应。最近,新的代谢组学方案使得探索人类血液中迄今已鉴定出的α-TOH不同代谢物(即“维生素E代谢组”)的这种差异成为可能,其中一些代谢物已被报道具有重要的生物学功能。这些进展促使我们定义不同α-TOH摄入量水平下这些代谢物的参考值和个体间差异程度。为此,对17名健康志愿者进行了为期一周、每天服用800 U RRR-α-TOH的口服给药方案,并在干预前和干预结束时利用最近验证的液相色谱-串联质谱(LC-MS/MS)程序测量血浆中的α-TOH代谢物;通过免疫印迹法在外周血白细胞中评估α-TOH的两个可能在该维生素的代谢和功能中起作用的靶基因,即孕烷X受体(PXR)和细胞色素P450同工酶4F2(CYP4F2)的表达。酶促代谢物水平显示出显著的个体间差异,补充后这种差异通常会增加。除了α-CEHC(羧乙基-羟基色满)以及长链代谢物M1和α-13'OH外,发现这种差异会干扰将它们用作α-TOH摄入量敏感指标的可能性。相反,自由基衍生的代谢物α-生育酚醌与补充后α-TOH的水平显著相关。补充刺激了白细胞中PXR的表达,但未刺激CYP4F2的表达,并且在α-TOH的基线水平与PXR的基线水平和补充后水平之间均观察到显著相关性。这些发现提供了有关α-TOH人体代谢及其内在变异性的原始分析和分子信息,这在未来的营养基因组学和干预研究中值得考虑。