Regulation of the Stress-axis by Vitamin D3 in Subjects With Multiple Sclerosis; a Double-blinded, Randomized, Placebo-controlled Study

The lifetime incidence of a major depression in Multiple Sclerosis (MS) is 50%. (Patten et al. Neurology 2003; 61(11):1524-7) Our group reported a negative correlation between vitamin D status and depression score of the Hospital Anxiety and Depression Scale (HADS) in a cross-sectional dataset of Dutch MS patients. (Knippenberg et al. Acta Neurol Scand 2011; 124(3):171-5) This suggests an interaction between vitamin D and biological mechanisms affecting susceptibility to depression. Currently, we have two main hypotheses: 1) Vitamin D regulates the hypothalamic stress axis in MS. Based on our findings that cortisol releasing hormone (CRH)-positive hypothalamic neurons in the brains of MS patients stained positive for the vitamin D receptor (VDR) and 1,25(OH)2D-24-hydroxylase (24-OHase). (smolders et al. J Neuropathol Exp Neurol 2013;72(2):91-105) 2) Vitamin D affects T cell cytokine profile and hereby the odds of developing depression. Also in non-MS depressed patients increased levels of pro-inflammatory cytokines are detected (Maes et al. Metab Brain Dis 2009; 24: 27-53). Vitamin D3 has shown to be a potent promotor of T cell regulation both in vitro and in vivo. (Smolders et al. J Neuroimmunol 2008;194:7-17 and Smolders et al. PLoS One 2010;5:e15235) The main goal of this study is to assess whether supplementation of high doses vitamin D3 results in a suppression of saliva cortisol day-curves in subjects with multiple sclerosis, and we will explore whether the pro-inflammatory cytokine profile of T lymphocytes is regulated.