Page 20 - AN-2-3

Advanced Neurology The role of gut in multiple sclerosis

2.2. Clinical evidence from MS patients alleviated by Akkermansia cultured from MS patients, and
+
2.2.1. Akkermansia this improvement was associated with a decrease in ɣδ
and IL-17-producing T cells .
[36]
A mucus-degrader called Akkermansia converts mucin to
short-chain fatty acids (SCFAs) which could influence the 2.2.2. Clostridia
[15]
effects on the immune system . It has been found to have There were important differences in the species abundance
both regulatory and inflammatory activities . Alternately, of 21 species noted in the gut of roughly 20 Japanese
[28]
pro-inflammatory pathways, such as the actuation of MS patients. Of the 21 species, a reduction in 19 species
complement and coagulation cascades as well as the over- was noticeable in MS samples, and 14 of them belonged
expression of genes related to antigen-presentation, B to Clostridia clusters XIVa and IV. It has been identified
cell, and TCR signaling, and pro-inflammatory pathways, that several organisms, including Parabacteroides and
[29]
have been linked to Akkermansia . Its capacity to break Prevotella (Bacteroidetes), Adlercreutzia and Collinsella
down mucus, which results in the collapse of the intestinal (Actinobacteria), and Erysipelotrichaceae (Firmicutes), were
epithelium barrier as well as a greater baring of local decreased in relapsing-remitting MS (RRMS) as compared
immune cells to microbic antigens, may be the cause of to HCs . Prevotella, Parabacteroides, and Adlercreutzia are
[37]
these inflammation-promoting characteristics . linked to the metabolism of phytoestrogens as well as the
[30]
Gene sequencing of the gut microbes in stool samples plant-derived xenoestrogen, whereas Parabacteroides and
from patients with MS showed Acinetobacter calcoaceticus Erysipelotrichaceae are involved in bile acid metabolism,
and Akkermansia muciniphila had much higher levels which also plays a critical role in Th17 inflammation and
whereas Parabacteroides distasonis had significantly lower MS [38-40] . In addition, there was a study that analyzed the gut
levels. A. muciniphila promoted Th1 cell differentiation, microbes of MS patients who had yet to receive therapy in
causing pro-inflammatory responses in mononuclear cells the early stages of the disease and compared them among
of MS patients. When MS patient microbiota was given to Caucasians, Hispanics, and African Americans. Early-stage
GF mice, the animals had more severe EAE symptoms and MS patients from all three ethnic groups had an elevated
fewer regulatory T cells (Tregs) . In untreated MS twins, relative abundance of Clostridia, indicating a connection
[7]
Akkermansia species were also found to be increased . between the etiology of MS and Clostridia. Two studies
[31]
Faecalibacterium levels were found to be lower in MS identified variations in specific Clostridium operational
patients. They also looked into variations in bacterial taxonomic units between treated and untreated MS people,
makeup between patients who received glatiramer while no appreciable alterations between all MS patients
acetate treatment and those who did not (Bacteroidaceae, and controls, raising the possibility that these drugs’
Faecalibacterium, Ruminococcus, Lactobacillaceae, antibacterial capabilities might change the microbiome [8,35] .
Clostridium, and other Clostridiales). Patients with MS, A strain that proportionally increased in MS, Collinsella,
who were not given any treatment, showed a rise among the has currently been found to be related to the changes in
species Akkermansia, Faecalibacterium, and Coprococcus intestinal permeability in MS patients as well as the rise of
following vitamin D administration in comparison to the pro-inflammatory cytokine IL-17A [41,42] .
the other groups . Although the detailed mechanism of 2.2.3. Prevotella
[8]
vitamin D is still uncertain, some studies have reported
that it binds to the vitamin D receptor and downregulates Cosorich et al. investigated the potential relationship
NLRP3/Caspase-1/GSDMD pyroptosis pathway, which is with changes in the intestinal microbiota of MS patients.
also activated in gut epithelial cells and associated with They examined the microbes that were separated from
gut inflammation [32-34] . A change in intestinal microbes small intestinal tissues and noticed that in comparison to
from MS patients was observed by Jangi et al. Rise in HCs and MS patients without clinical symptoms, those
Methanobrevibacter and Akkermansia with lessening with increased disease activity and a rise in the number
in Butyricimonas are among the microbiome changes of intestinal Th17 cells had an elevated Firmicutes/
associated with MS, which are also connected to changes Bacteroidetes ratio, a larger relative abundance of
in the activation of genes related to dendritic cell (DC) Streptococcus, and fewer Prevotella strains. It showed that
maturation, IFN signaling, as well as Nuclear factor the relative frequency of Prevotella strains in the human
kappa B signaling pathways among circulating T cells small intestine is negatively correlated with the frequency
and monocytes. When compared to those who are not of gut Th17 cells. It demonstrates that abnormal Th17
receiving treatment, patients receiving disease-modified cell growth in the human gut and certain microbiome
treatment had higher abundances of Prevotella and changes are linked to cerebral autoimmunity .
[10]
Sutterella and lower abundances of Sarcina . EAE was Mangalam et al. also report that Prevotella histicola
[35]
Volume 2 Issue 3 (2023) 3 https://doi.org/10.36922/an.413