Abstract: P678

Type: Poster Sessions

Abstract Category: Clinical aspects of MS - Epidemiology

Background: Studies suggest that the gut microbiota may play a vital role in multiple sclerosis (MS). We performed a systematic review, synthesizing the current body of knowledge on the MS gut microbiota composition compared to controls.
Methods: We performed a literary search of MEDLINE, EMBASE, and Web of Science of original research articles published in English between Jan/2008-Feb/2018 that included a quantified assessment of the gut microbiota composition in individuals with MS and healthy controls. The protocol was lodged with the International Prospective Register of Systematic Reviews (#CRD42018089173).
Results: Of 375 reports identified, 10 fulfilled the study criteria for inclusion in the systematic review. All 10 studies used a case-control design - 9 focused on adults and 1 on children, for a total of 286 MS and 296 healthy control samples. Over 90% of MS cases had a relapsing-remitting disease course. Disease duration ranged from 10.6±6.5 months to 15.3±8.6 years (mean±SD). Six studies sourced participants from the US, 2 from Germany, 1 Italy, and 1 Japan. Nine studies assessed stool and 1 examined duodenal mucosa samples. Diverse microbial quantification platforms included: Illumina MiSeq (3 studies), Roche 454 (4 studies), microarray (2 studies), and fluorescence in situ hybridization (1 study). No study reported a significant difference in any gut microbiota α-diversity metric in MS vs. healthy controls (all p>0.05); in contrast, 2 studies reported a difference in β-diversity (p< 0.05). At the taxa-level, consistent observations (reported in ≥2 studies) included: at the genus level, lower relative abundance of Prevotella and the Archaea Methanobrevibacter in MS vs. healthy controls. At the species level, lower relative abundance of Faecalibacterium prausnitzii, Bacteroides coprophilus, Bacteroides plebeius, and Prevotella copri and higher of Akkermansia muciniphila and Eubacterium biforme in MS vs. healthy controls. Though most studies were too small to assess potential confounders, exposure to an MS immune-modifying drug (IMD) was associated with gut microbiota differences in 3 of 3 studies in which this was examined.
Conclusion: While all studies were relatively small, consistent significant taxonomic differences were reported. Further, in most studies, gut diversity did not differ between MS cases and healthy controls. IMDs were associated with differences in the gut microbiota but this should be better informed by longitudinal studies.
Disclosure: This work is supported by The Multiple Sclerosis Scientific and Research Foundation (PI: Tremlett, EGID: 2636). The funding source has no role in the study design, collection, analysis or interpretation of the data, or in the decision to submit the article for publication
AM was funded through a The Multiple Sclerosis Scientific and Research Foundation (PI: Tremlett, EGID: 2636).
JF was funded through a The Multiple Sclerosis Scientific and Research Foundation (PI: Tremlett, EGID: 2636).
FZ was funded through research grants held by Tremlett.
CB is supported in art by the Bingham Chair in Gastroenterology. He has been on the advisory boards for Abbvie Canada, Ferring Canada, Janssen Canada, Shire Canada, Takeda Canada, Pfizer Canada and Napo Pharmaceuticals and consulted to 4D Pharma and Mylan Pharmaceuticals. He has received educational grants from Abbvie Canada, Pfizer Canada, Shire Canada, Takeda Canada, Janssen Canada and has been on the speaker's panel for Ferring Canada and Shire Canada.
GV is funded through the Public Health Agency of Canada and the federal Genomics Research & Development Initiative; he is currently receiving funds for gut microbiome research through The Multiple Sclerosis Scientific and Research Foundation (PI: Tremlett, EGID: 2636).
MG is funded through the Public Health Agency of Canada and the federal Genomics Research & Development Initiative; she is currently receiving funds for gut microbiome research through The Multiple Sclerosis Scientific and Research Foundation (PI: Tremlett, EGID: 2636).
EW is funded by the NMSS, the PCORI and the Race to Erase MS.
HT is the Canada Research Chair for Neuroepidemiology and Multiple Sclerosis and in the last 3 years has received research support from: the MS Society of Canada, the MS Scientific and Research Foundation, the National Multiple Sclerosis Society; the Canadian Institutes of Health Research, the Canada Foundation for Innovation and the UK MS Trust.