UCSF

Author Of 1 Presentation

Microbiome Late Breaking Abstracts

LB01.05 - Network analysis identifies gut bacteria associated with multiple sclerosis relapse among pediatric-onset patients

Abstract

Background

Commensal gut microbes are known to affect host immune function and may be modifiable. Recent work suggests gut microbiota composition contributes to onset of MS; however, little is known about its contribution to MS disease activity.

Objectives

Estimate the association between gut microbiota and subsequent disease activity among individuals with pediatric-onset MS (pedMS) from the U.S. Network of Pediatric MS Centers.

Methods

Stool samples were collected from cases (MS symptom onset <18 years) and profiled using 16S rRNA sequencing of the V4 region. Amplicon sequence variants (ASVs) were identified using the Divisive Amplicon Denoising Algorithm-2 (DADA2). ASVs present in <20% of samples were removed. ASV clusters (modules) were identified using weighted genetic correlation network analysis (WGCNA) and sparCC transformation of ASV abundance. Cox proportional hazard recurrent event models were used to examine the relationship between individual ASVs and then ASV clusters, adjusted for age, sex, and disease modifying therapy (DMT) use.

Results

Of 53 pedMS cases, 72% were girls. At stool sample collection, the mean age was 15.5 years (SD: 2.7) and disease duration was 1.1 years (SD: 1.0). Less than half (45%) had one relapse and 30% had >1 relapse over the subsequent mean follow-up of 2.5 years (SD:1.3). Over this time, 91% used a DMT. Among 270 individual ASVs included in the analyses, 20 were nominally significant (p<0.05), e.g. the presence of Blautia stercoris was associated with higher relapse risk (hazard ratio [HR]=2.50; 95% confidence interval [CI]=1.43, 4.37). WGCNA identified 6 ASV modules. Higher values of one module’s eigengene was significantly (false discovery rate q<0.2) associated with higher relapse risk (HR=1.23, 95% CI=1.02, 1.50). Four ASVs nominally associated with higher relapse risk were in this module. These included Blautia massiliensis, Dorea longicatena, Coprococcus comes, and an unknown species in genus Subdoligranulum.

Conclusions

We found that a high relative abundance of a gut microbiota species within the Blautia genus, and its interconnected variants, was associated with a higher relapse risk in pedMS cases. While our study represents the largest of its kind in MS, findings need to be replicated. However, Blautia stercoris has been linked to disease activity in other immune-mediated diseases such as systemic lupus erythematosus.

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Author Of 1 Presentation

Microbiome Poster Presentation

P0679 - The gut microbiota: a case-control study of children with multiple sclerosis, monophasic acquired demyelinating syndromes and unaffected controls (ID 102)

Abstract

Background

The gut microbiota may influence multiple sclerosis (MS) onset. Pediatric MS offers the opportunity to examine pathological processes close to risk acquisition.

Objectives

To examine the gut microbiota from stool samples of persons with pediatric onset MS, or monophasic acquired demyelinating syndromes (ADS) and unaffected controls in a case-control study.

Methods

Persons ≤21 years old with symptom onset <18 years of age with either MS (McDonald criteria) or ADS were eligible, as were unaffected controls with no known neurological or immune-mediated condition (migraine, asthma/allergies were permissible) were enrolled via the Canadian Pediatric Demyelinating Disease Network. Stools were collected between Nov/2015–Mar/2018, shipped on ice, and stored at -80°C. The 16S ribosomal RNA gene (V4 region) was amplified from extracted DNA and sequenced via the Illumina MiSeq platform. Amplicon sequence variants were used to compare the gut microbiota by disease status (MS/ADS/controls). The MS cases were also compared by disease-modifying drug (DMD) status (exposed/naïve). Negative binomial regression was used for genus-level analyses, with rate ratios adjusted (aRR) for age and sex.

Results

Of the 32/41/36 included MS/ADS/control participants, 24/23/21 were girls, averaging age 16.5/13.8/15.1 years at stool sample, respectively. The MS/ADS cases were 14.0/6.9 years at symptom onset. The 3 groups (MS/ADS/controls) were relatively similar for: body mass index (median: 22.8/19.7/19.9), presence of constipation (number of participants with a Bristol Stool Scale score of 1 or 2=8/9/7) and diet (% caloric intake for fat (median)=34/35/34 and for fibre (median)=9/10/11 g/day). Nine MS cases (28%) were DMD naïve. Gut microbiota diversity (alpha and beta) did not differ by disease (MS/ADS/controls), or DMD status (all p>0.1), while taxa-level findings did. For example, relative abundance of the Proteobacteria, Sutterella was depleted for MS cases vs controls and MS vs ADS cases (aRR:0.13;95%CI:0.03–0.59 and 0.21;95%CI:0.05–0.98), but did not differ for the ADS cases vs controls or by DMD status for the MS cases (all p>0.1). Several of the butyrate-producing genera within the Clostridia class (Firmicutes phylum) —Ruminococcaceae UCG−003, Lachnospiraceae UCG−008 and UCG−004—exhibited similar patterns.

Conclusions

Gut microbiota diversity was similar for individuals with pediatric MS relative to either monophasic ADS or unaffected controls. However, at the taxa-level, differences were observed which differentiated the MS cases from the monophasic ADS cases and controls.

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