The calcitonin/calcitonin gene related peptide-alpha gene is not required for 1alpha,25-dihydroxyvitamin D3-mediated suppression of experimental autoimmune encephalomyelitis

Hormones in experimental autoimmune encephalomyelitis (EAE) animal models

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) in which activated immune cells attack the CNS and cause inflammation and demyelination. While the etiology of MS is still largely unknown, the interaction between hormones and the immune system plays a role in disease progression, but the mechanisms by which this occurs are incompletely understood. Several in vitro and in vivo experimental, but also clinical studies, have addressed the possible role of the endocrine system in susceptibility and severity of autoimmune diseases. Although there are several demyelinating models, experimental autoimmune encephalomyelitis (EAE) is the oldest and most commonly used model for MS in laboratory animals which enables researchers to translate their findings from EAE into human. Evidences imply that there is great heterogeneity in the susceptibility to the induction, the method of induction, and the response to various immunological or pharmacological interventions, which led to conflicting results on the role of specific hormones in the EAE model. In this review, we address the role of endocrine system in EAE model to provide a comprehensive view and a better understanding of the interactions between the endocrine and the immune systems in various models of EAE, to open up a ground for further detailed studies in this field by considering and comparing the results and models used in previous studies.

Regulatory T cell function correlates with serum 25-hydroxyvitamin D, but not with 1,25-dihydroxyvitamin D, parathyroid hormone and calcium levels in patients with relapsing remitting multiple sclerosis

Vitamin D is a potent immune modulator in multiple sclerosis (MS), but was primarily identified for its effects on calcium homeostasis. It is uncertain whether these calcaemic functions of vitamin D are critically involved in its immune modulating potential. We earlier reported a correlation between serum 25-hydroxyvitamin D (25(OH)D) levels and regulatory T cell (Treg) function. In the present study, the correlation of serum levels of 1,25-dihydroxyvitamin D (1,25(OH)2D), intact parathyroid hormone (PTH), and total calcium with Treg number and functionality and the proportions of other T helper cell subsets was assessed in 29 relapsing remitting MS patients. In contrast to serum 25(OH)D levels, serum concentrations of neither 1,25(OH)2D, nor PTH and total calcium correlated significantly with Treg function or Th1/Th2 ratio. None of the parameters correlated with the relative and absolute number of Tregs. Interestingly, the serum levels of 1,25(OH)2D correlated positively with the proportion of T helper type 17 (Th17) cells. These results suggest that the serum levels of 1,25(OH)2D, PTH, and total calcium are not critically involved in the correlation between vitamin D status and T cell regulation.