ABSTRACT
The benecial effects of vitamin D in several diseases, such as preventing bone loss, protecting neurons from degeneration, boosting immune response, preventing diabetes/diabetic toxicity, and acting as an anticancer agent, are well documented [1-6]. This encourages vitamin D supplementation in the general healthy population. Vitamin D maintains calcium homeostasis and participates in multiple cellular processes, such as differentiation, proliferation, and metabolism, through both nongenomic action and its cognate receptor (VDR)-mediated transcriptional regulation [6,7]. Emerging evidence supports that maintenance of cellular reductive-oxidative (redox) homeostasis can account for many of these vitamin D actions, yet the role of vitamin D in regulating cellular oxidative status remains controversial. This conict raises concerns since improper levels of oxidative stress can lead to catastrophic outcomes. Therefore, in this chapter, we intend to cover the
5.1 Introduction .......................................................................................................................... 131 5.2 Oxidative Stress .................................................................................................................... 132
5.2.1 Source of Oxidative Stress ........................................................................................ 132 5.2.2 Redox Balance Maintenance .................................................................................... 132
5.3 Antioxidant Role of Vitamin D ............................................................................................ 134 5.3.1 Cancer ....................................................................................................................... 134
5.3.1.1 Colorectal Cancer ...................................................................................... 135 5.3.1.2 Breast Cancer ............................................................................................. 135 5.3.1.3 Prostate Cancer .......................................................................................... 135 5.3.1.4 Liver Cancer ............................................................................................... 136
5.3.2 Alcoholic Myopathy ................................................................................................. 136 5.3.3 Cardiovascular Disease ............................................................................................ 136
5.3.3.1 CKD-Related Cardiovascular Disease....................................................... 136 5.3.3.2 Atherosclerosis ........................................................................................... 136
5.3.4 Diabetes .................................................................................................................... 137 5.3.5 Skin ........................................................................................................................... 137 5.3.6 Neuron ...................................................................................................................... 138
5.4 Prooxidant Role of Vitamin D .............................................................................................. 138 5.4.1 Cancer ....................................................................................................................... 138
5.4.1.1 Breast Cancer ............................................................................................. 138 5.4.1.2 Leukemia ................................................................................................... 139
5.4.2 Inammation-Related Disease ................................................................................. 140 5.4.2.1 Obesity ....................................................................................................... 140 5.4.2.2 Vascular Calcication ................................................................................ 141
5.4.3 Bone .......................................................................................................................... 141 5.5 Conclusion ............................................................................................................................ 141 References ...................................................................................................................................... 146
studies on the effect and mechanism of vitamin D in regulating cellular oxidative stress responses. The following summarizes recent discoveries from studies investigating the anti-and prooxidation effects of vitamin D and the underlying mechanisms through which vitamin D mediates both aspects. There are many forms of vitamin D applied in these studies, including the precursor forms, vitamin D2 (VD2), vitamin D3 (VD3),25-hydroxyvitamin D3 (25-VD), the active form of vitamin D3 (1alpha,25-dihydroxyvitamin D3, 1,25-VD), and low-calcemic active analogs. Furthermore, the systems, including cell types, application route, and dosages of vitamin D metabolites, and assays measuring oxidative stress applied in each study are varied and therefore should be compared and discussed. Results from these studies might lead to the establishment of guidelines for vitamin D supplementation, so that appropriate dosages and forms of vitamin D can be applied to individual disease types.
