Engin Kaya Nusret
Bağcilar Education and Research Hospital, Department of Ophthalmology, Istanbul, Turkey.
Mol Vis. 2009;15:855-60. Epub 2009 Apr 23.
Vitamin E is an important natural antioxidant, and its most common and biologically active form is alpha-tocopherol. In addition to this, specific regulatory effects of vitamin E have been revealing. The body exerts a certain effort to regulate its tissue levels with specific tocopherol transport proteins and membrane receptors. Antiproliferative and protein kinase C-suppressing effects of alpha-tocopherol have been previously demonstrated, which have not been mimicked by beta-tocopherol or probucol. Protein kinase C promises to be an important area of interest in the means of glaucoma and cataractogenesis. It has been shown in different models that retinal vascular dysfunction due to hyperglycemia could be prevented by alpha-tocopherol via the diachylglycerol-protein kinase C pathway. Glutamate transporter activity has been shown to be modulated by protein kinase C. This pathway is also important in intraocular pressure-lowering effects of prostaglandin and its analogs in glaucoma therapy. Filtran surgery became another possible area of usage of alpha-tocopherol since its antiproliferative effect has been demonstrated in human Tenon's capsule fibroblasts. Prevention of posterior capsule opacification is another area for future studies. It is evident that when correct and safe modulation is the objective, alpha-tocopherol merits a concern beyond its mere antioxidant properties.
维生素E是一种重要的天然抗氧化剂，其最常见且具有生物活性的形式是α-生育酚。除此之外，维生素E的特定调节作用也不断被揭示。机体通过特定的生育酚转运蛋白和膜受体来调节其组织水平。α-生育酚的抗增殖和抑制蛋白激酶C的作用此前已得到证实，而β-生育酚或普罗布考则无法模拟这些作用。在青光眼和白内障形成机制方面，蛋白激酶C有望成为一个重要的研究热点。不同模型研究表明，α-生育酚可通过二酰甘油-蛋白激酶C途径预防高血糖导致的视网膜血管功能障碍。研究显示，蛋白激酶C可调节谷氨酸转运体活性。该途径在青光眼治疗中前列腺素及其类似物降低眼压的作用方面也很重要。由于α-生育酚在人眼球筋膜成纤维细胞中已显示出抗增殖作用，滤过性手术成为其另一个可能的应用领域。预防后囊膜混浊是未来研究的另一个方向。显然，当目标是进行正确且安全的调节时，α-生育酚除了其单纯的抗氧化特性外，还值得关注。
