School of Nutritional Sciences and Dietetics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
J Mol Neurosci. 2013 Oct;51(2):478-84. doi: 10.1007/s12031-013-0090-9. Epub 2013 Aug 17.
Vitamin A and its derivatives have been shown to modulate the immune system via retinoic acid receptor (RAR). This study explored the impact of retinyl palmitate supplementation on RAR subtype gene expression in peripheral blood mononuclear cells (PBMCs) in multiple sclerosis (MS) patients. The study designed as a double-blind randomized clinical trial in which relapsing remitting multiple sclerosis patients were evaluated. Both groups received one capsule 50,000 IU vitamin D3 per 2 weeks and one intramuscular injection interferon beta-1a per week. The intervention group received one 25,000 IU retinyl palmitate capsule daily for 6 months and the placebo group received one placebo capsule daily. The PBMCs were isolated from participants and the expression level changes of RAR-α and RAR-γ genes were determined by real-time PCR. After supplementation, in the intervention group, the RAR-α gene expression level was significantly decreased compared to the placebo group (p = 0.03); however, the expression of RAR-γ gene did not significantly change (p = 0.10). These results show that vitamin A supplementation can significantly downregulate the expression of RAR-α gene in PBMCs of MS patients that suggest the presence of in vivo regulatory mechanisms for the action of vitamin A on the immune system.
维生素 A 及其衍生物已被证明可通过视黄酸受体 (RAR) 调节免疫系统。本研究探讨了棕榈酸视黄酯补充对多发性硬化症 (MS) 患者外周血单个核细胞 (PBMC) 中 RAR 亚型基因表达的影响。该研究设计为一项双盲随机临床试验，对复发缓解型多发性硬化症患者进行评估。两组患者均每 2 周接受一次 50,000 IU 维生素 D3 胶囊，每周接受一次肌肉内注射干扰素 beta-1a。干预组每天服用一粒 25,000 IU 棕榈酸视黄酯胶囊，持续 6 个月，而安慰剂组每天服用一粒安慰剂胶囊。从参与者中分离 PBMC，并通过实时 PCR 确定 RAR-α 和 RAR-γ 基因的表达水平变化。补充后，与安慰剂组相比，干预组 RAR-α 基因表达水平显著降低（p = 0.03）；然而，RAR-γ 基因的表达没有明显变化（p = 0.10）。这些结果表明，维生素 A 补充可显著下调 MS 患者 PBMC 中 RAR-α 基因的表达，提示维生素 A 对免疫系统的作用存在体内调节机制。
