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Differential Uptake of RRR α‐Tocopherol, All‐racemic α‐Tocopherol, and RRR γ‐Tocopherol into Primary Human Aortic Smooth Muscle Cells
Author(s) -
Ranard Katherine M,
Kuchan Matthew J,
Lai ChronSi,
Erdman John W
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.800.3
Subject(s) - chemistry , tocopherol , vitamin e , vitamin , biochemistry , antioxidant , chromatography
Alpha‐tocopherol (α‐Toc), one of the eight compounds constituting vitamin E, may play a role in preventing atherosclerosis in humans. Previous studies have shown that severe α‐Toc deficiency promotes atherosclerosis in mice and that α‐Toc is anti‐inflammatory. In contrast, another vitamin E vitamer, γ‐tocopherol (γ‐Toc), may be pro‐inflammatory. A synthetic ( all‐racemic ) form of α‐Toc is also commonplace in our food supply; this is important because humans may have a biological preference for natural (RRR) α‐Toc. Consuming foods with differing forms of tocopherol could impact the vitamin E profile in human tissues. Our in vitro study aimed to compare these three human disease‐relevant tocopherol forms (RRR α‐Toc, all‐racemic α‐Toc, and RRR γ‐Toc), by first focusing on uptake of the vitamers into human vascular aortic smooth muscle cells (HVASMC). Primary HVASMC (pass <8) were grown to 70% confluency in 6‐well plates. RRR α‐Toc, all‐racemic α‐Toc, and RRR γ‐Toc were added to the media in DMSO (0.2% v/v) at 25uM to simulate physiological conditions of human serum. DMSO vehicle was also added to cells alone to serve as a control. After 24, 48, and 72 hours of incubation, cells from each treatment well (n=3 per group) were trypsinized and pelleted. Tocopherols were extracted from the HVASMC and analyzed via high‐performance liquid chromatography (HPLC). After 48 hours, there was an approximately 5‐fold higher cell uptake of γ‐Toc than all‐racemic α‐Toc and a 6‐fold higher γ‐Toc uptake compared to RRR α‐Toc. After 72 hours, there was an approximately 6.5‐fold higher and 7.5‐fold higher cell uptake of γ‐Toc than all‐racemic α‐Toc and RRR α‐Toc, respectively. We will also report the impact of these vitamers on the transcription of atherosclerosis‐related genes in this cell line, as well as how stimulation by a pro‐inflammatory cytokine (TNF‐α) following a dose of tocopherol impacts the gene expression profiles. Differential changes in gene expression between the three tocopherol forms could support the suggested non‐antioxidative functions of RRR α‐Toc, as well as distinguish the impact of the individual tocopherol isomers. Support or Funding Information Funding provided by Abbott Nutrition through the Center for Nutrition, Learning and Memory, University of Illinois, Urbana‐Champaign, and NIH grant P51OD011092.