Intestinal MAdCAM-1 imaging as biomarker for prognostic in murine models of multiple sclerosis.

Introduction: Multiple sclerosis (MS) is an autoimmune disease of the central nervous system. Recent evidence suggests that lymphocyte trafficking in the intestines could play a key role in its etiology. Nevertheless, it is not clear how intestinal tissue is involved in the disease onset nor its evolution. In the present study, we aimed to evaluate intestinal inflammation dynamic throughout the disease course and its potential impact on disease progression.

Methods: We used tissue immunophenotyping (immunohistofluorescence and flow cytometry) and a recently described molecular magnetic resonance imaging (MRI) method targeting mucosal addressin cell adhesion molecule-1 (MAdCAM-1) to assess intestinal inflammation in vivo in two distinct animal models of MS (Experimental Autoimmune Encephalomyelitis - EAE) at several time points of disease progression.

Results: We report a positive correlation between disease severity and MAdCAM-1 MRI signal in two EAE models. Moreover, high MAdCAM-1 MRI signal during the asymptomatic phase is associated with a delayed disease onset in progressive EAE and to a lower risk of conversion to a secondary-progressive form in relapsing-remitting EAE. During disease evolution, in line with a bi-directional immune communication between the gut and the central nervous system, we observed a decrease in T-CD4 and B lymphocytes in the ileum concomitantly with their increase in the spinal cord.

Conclusion: Altogether, these data unveil a crosstalk between intestinal and central inflammation in EAE and support the use of molecular MRI of intestinal MAdCAM-1 as a new biomarker for prognostic in MS patients.