A commercial probiotic induces tolerogenic and reduces pathogenic responses in experimental autoimmune encephalomyelitis

Previous studies in experimental autoimmune encephalomyelitis (EAE) models have shown that some probiotic bacteria beneficially impact the development of this experimental disease. Here, we tested the therapeutic effect of two commercial multispecies probiotics—Lactibiane iki and Vivomixx—on the clinical outcome of established EAE. Lactibiane iki improves EAE clinical outcome in a dose-dependent manner and decreases central nervous system (CNS) demyelination and inflammation. This clinical improvement is related to the inhibition of pro-inflammatory and the stimulation of immunoregulatory mechanisms in the periphery. Moreover, both probiotics modulate the number and phenotype of dendritic cells (DCs). Specifically, Lactibiane iki promotes an immature, tolerogenic phenotype of DCs that can directly induce immune tolerance in the periphery, while Vivomixx decreases the percentage of DCs expressing co-stimulatory molecules. Finally, gut microbiome analysis reveals an altered microbiome composition related to clinical condition and disease progression. This is the first preclinical assay that demonstrates that a commercial probiotic performs a beneficial and dose-dependent effect in EAE mice and one of the few that demonstrates a therapeutic effect once the experimental disease is established. Because this probiotic is already available for clinical trials, further studies are being planned to explore its therapeutic potential in multiple sclerosis patients.This research was funded by the Fondo de Investigación Sanitaria, Instituto de Salud Carlos III; was cofunded by the European Union (European Regional Development Fund/European Social Fund) “A way to build Europe” under grants PI15/00840, PI18/00357, RD16/0015/004, and RD16/0015/0019; and was funded by “Agència de Gestió d’Ajuts Universitaris i de Recerca” (AGAUR; Generalitat de Catalunya) under grant 2017SGR527.Peer reviewe