Immunomodulatory and anti-inflammatory effects of probiotics in multiple sclerosis: a systematic review

Abstract

Multiple sclerosis (MS) is an inflammatory and autoimmune neurological disorder which leads to demyelination. Although the etiology of MS is yet to be known, it appears that regulating the immune system and suppressing inflammatory pathways may possibly have a favorable effect on the healing of this disease. Evidence suggests that probiotics consumption via gut microbiome alteration devises beneficial effects in improving immune and inflammatory responses in MS. All articles were systematically searched (in the main databases) for this paper. Two investigators independently scrutinized full texts of the potentially eligible articles. The quality of the study was evaluated using standardized tools. The methodological quality of seven studies included in this review ranged from fair to good. The findings illustrated that there were statistically significant improvements in the static and dynamic balance in patients and animals with MS. In the paper in hand, the effects of probiotics administration on immune and inflammatory markers in MS disease are evaluated. In addition, the limitations and knowledge gaps were reported while proposing a possible mechanism of probiotics therapy in modulating immune and inflammatory responses. This systematic review indicated that the probiotics could improve immune and inflammatory parameters, the cytokines and cells in MS disease. Probiotics may have efficient effects in management and treatment of MS. More studies are required to clarify the effect of supplementation with probiotics and their mechanisms in MS disease.

Keywords: Autoimmune diseases; Gut microbiota; Gut-brain axis; Immune/inflammatory response; Microbiome; Multiple sclerosis; Probiotics; Systematic review.

Fig. 1

Collection of studies for inclusion in systematic review

Fig. 2

Probiotic mechanisms in the gastrointestinal tract. Probiotics administration may manipulate gut microbial composition and reduce growth of pathogens and stimulate mucin secretion via stimulation of Goblet cells. Probiotic-mediated immunomodulation may occur through mediation of cytokine secretion through TLRs (ECs, DCs, and MQs), which can also affect proliferation and differentiation of immune cells (T-cells, CD cells, B cells) especially T-reg cells which resulted in an increase of IL-10 and TGF-β. Also, probiotics, through amplification of TJs, could improve gut permeability and also decrease entrance of LPS and pathogens from lumen into circulation. T-reg, regulatory T-cell; TLRs, toll-like receptors; ECs, endothelial cells; DCs, dendritic cells; MQs, macrophage cells; IL, interleukin; CD, cluster of differentiation; TGF-β, transforming growth factor beta; TNF-α, Tumor necrosis factor alpha; IFN-γ, Interferon gamma; TJPs, tight junction proteins; Ig, immunoglobulin g