Non-calcitropic roles of calcitriol in the cardiovascular system — a narrative review

Abstract

Background: Vitamin D is a secosteroid with the elemental formula of C₂₇H₄₄O, and vitamin D2 and D3 are its two distinct forms. Cutaneous synthesis and diet are two main sources of delivering vitamin D. It is converted into its active hormonal form to exert its biological actions and plays an important, pleiotropic role, as the diverse activities of vitamin D are mediated through both genomic and non-genomic pathways. Aside from its traditional roles in the regulation of mineral homeostasis, vitamin D has also been shown to mediate a number of additional non-genomic or “rapid” actions at the non-transcriptional level in a variety of tissues. It has been shown to protect against endothelial dysfunction, smooth vascular muscle cell proliferation and migration, and modulation of the immune system, as well as the inflammatory response. Although some vitamin D is essential for cardiovascular health, excess may have detrimental effects, particularly on elastogenesis and inflammation of the arterial wall. The detection of Vitamin D receptors in
almost all tissues of the body spurred wide interest in its physiological functions. The primary purpose of this review was to provide an overview of the metabolism, mechanism of actions, homeostatic regulations, and non-calcitropic roles of Vitamin D in the vasculature. Methodology: Literature search using the combination(s) of the following key terms: “cardiovascular System,” “Metabolism,” “Non-calcitropic Role,” “Regulation,” and “Vitamin D” was used to identify relevant studies that were used for this review. The search was restricted to articles written in English language, but no time limit restriction was used. Out of the retrieved studies, only those the relevant information as assessed by the authors were used to write this review.