Vitamin d as an immunomodulatory and antioxidant molecule: Association between vitamin d deficiency and systemic sclerosis

Abstract

Vitamin D is activated in skin of mammals through sun light or a small amount of vitamin D is taken in with diet. Biologically inactive form of vitamin D is hydroxylated in liver and is converted to its active form, 1-25 dihydroxyvitamin D3 in renal tubule. Active form of vitamin D is known as a prohormone and associated with vitamin D receptor (VDR). Biological functions that initiate with binding of Vitamin D to VDR are related to many processes such as mineral metabolism, regulation of cell proliferation and differentiation, as well as its association with regulation of immune response and control of oxidative stress. Systemic sclerosis (SS) is an autoimmune disease characterized by skin and internal organ involvement. Its etiology is still unclear however it is accepted that oxidative stress is one of the most important mechanisms of pathogenesis. This review summarizes the current worldwide literature on vitamin D metabolism and its molecular pathway, effects of vitamin D as an immunomodulatory and antioxidant molecule, current hypotheses for SS pathogenesis as a rare autoimmune disease and the importance of oxidative stress and vitamin D deficiency in SS patients.