Department of Internal Medicine, Laboratory of Clinical Biochemistry and Nutrition, University of Perugia, Perugia, Italy.
Biofactors. 2010 Jan-Feb;36(1):33-42. doi: 10.1002/biof.75.
Nearly after one century of research and thousands of publications, the physiological function(s) of vitamin E remain unclear. Available evidence suggests a role in cell homeostasis that occurs through the modulation of specific signaling pathways and genes involved in proliferative, metabolic, inflammatory, and antioxidant pathways. Vitamin E presence in the human body is under close metabolic control so that only alpha-tocopherol and, to a lower extent, gamma-tocopherol are retained and delivered to tissues. Other vitamin E forms that are not retained in the body in significant amounts, exhibit responses in vitro that are different form those of alpha-tocopherol and may include tumor cell specific toxicity and apoptosis. These responses provide a therapeutic potential for these minor forms, either as such or metabolically modified, to produce bioactive metabolites. These cellular effects go beyond the properties of lipophilic antioxidant attributed to alpha-tocopherol particularly investigated for its alleged protective role in atherosclerosis or other oxidative stress conditions. Understanding signaling and gene expression effects of vitamin E could help assign a physiological role to this vitamin, which will be discussed in this review. Besides vitamin E signaling, attention will be given to tocotrienols as one of the emerging topics in vitamin E research and a critical re-examination of the most recent clinical trials will be provided together with the potential use of vitamin E in disease prevention and therapy.
经过近一个世纪的研究和数千篇出版物，维生素 E 的生理功能仍不清楚。现有证据表明，它在细胞内稳态中发挥作用，通过调节特定的信号通路和参与增殖、代谢、炎症和抗氧化途径的基因来实现。人体中维生素 E 的存在受到密切的代谢控制，因此只有 α-生育酚和（在较低程度上）γ-生育酚被保留并输送到组织中。其他在体内没有大量保留的维生素 E 形式，在体外表现出与 α-生育酚不同的反应，可能包括肿瘤细胞特异性毒性和细胞凋亡。这些反应为这些次要形式提供了治疗潜力，无论是作为本身还是代谢修饰形式，以产生生物活性代谢物。这些细胞效应超出了归因于 α-生育酚的亲脂性抗氧化剂的特性，特别是针对其在动脉粥样硬化或其他氧化应激条件下的保护作用进行了研究。了解维生素 E 的信号转导和基因表达效应可能有助于为这种维生素赋予生理作用，这将在本文综述中进行讨论。除了维生素 E 的信号转导外，还将关注生育三烯酚作为维生素 E 研究中的一个新兴主题，并对最近的临床试验进行批判性重新审查，同时还将讨论维生素 E 在疾病预防和治疗中的潜在用途。
