University of British Columbia

Author Of 3 Presentations

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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Invited Presentations Invited Abstracts

PL01.01 - The MS Prodrome

Speakers
Authors
Presentation Number
PL01.01
Presentation Topic
Invited Presentations
Lecture Time
09:00 - 09:45

Abstract

Abstract

Historically, a prodromal period in multiple sclerosis (MS) was not thought to exist. A prodrome can be defined as an early set of signs or symptoms occurring before classical onset of a disease. For a chronic neurological disease such is MS, a prodromal phase could span months or years before ‘MS symptom onset.’ While prodromal phases have been relatively well recognized in other neurological conditions, such as Parkinson disease, the MS prodrome has received little consideration until recently. A better understanding of the MS prodrome could have profound implications for disease prevention and management. Thus, it is important for scientists across all disciplines, from bench researchers to epidemiologists, medical ethicistic, and clinical trialists, as well as clinicians, to be cognizant of this emerging area. However, although the field remains nascent, there is sufficient knowledge of the MS prodrome to affect current practice now, particularly research into risk factors for MS onset. Putative risk factors must be carefully evaluated in light of the MS prodrome. However, much more work is needed before the MS prodrome has direct application to routine clinical practice.

Session Objectives: To summarize and reflect on what is currently known, and not known, about the MS prodrome, and what the implications are for research and future clinical care of person’s with MS.

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Microbiome Oral Presentation

PS10.03 - Functional survey of the pediatric multiple sclerosis microbiome        

Speakers
Presentation Number
PS10.03
Presentation Topic
Microbiome
Lecture Time
09:45 - 09:57

Abstract

Background

Metagenomic sequencing reveals the functional potential of the gut microbiome, and may explain how the gut microbiome influences pediatric-onset multiple sclerosis (MS) risk.

Objectives

To examine the gut microbiome functional potential by metagenomic analysis of stool samples from pediatric MS cases and controls using a case-control design.

Methods

Persons ≤21 years old enrolled in the Canadian Pediatric Demyelinating Disease Network who provided a stool sample and were not exposed to antibiotics or corticosteroids 30 days prior were included for study. All MS cases met McDonald criteria, had symptom onset <18 years of age and had either no prior disease-modifying drug (DMD) exposure or were exposed to beta-interferon or glatiramer acetate only. Twenty MS cases were matched to 20 non-affected controls by sex, age (± 3 years), stool consistency (Bristol Stool Scale, BSS) and, when possible, by race. Shotgun metagenomic reads were generated using the Illumina NextSeq platform and assembled using MEGAHIT. Metabolic pathway analysis was used to compare the gut microbiome between cases and controls, as well as cases by DMD status (DMD naïve vs DMD exposed MS cases vs controls). Gene ontology classifications were used to assess α-diversity and differential abundance analyses (based on the negative binomial distribution) reported as age-adjusted log-fold change (LFC) in relative abundance, 95% confidence intervals (CI), and false discovery rate adjusted p-values.

Results

The MS cases were aged 13.6 mean years at symptom onset. On average, MS cases and controls were 16.1 and 15.4 years old at the time of stool collection and 80% of each group were girls. MS cases and controls were similar for body mass index (median: 22.8 and 21.0, respectively), stool consistency (BSS types 1-2: n=4, types 3-5: n=16, for both MS and controls) and race (Caucasian: 11 and 9, respectively). Eight MS cases were DMD naïve. Richness of gene ontology classifications did not differ by disease status or DMD status (all p>0.4). However, differential analysis of metabolic pathways indicated that the relative abundance of tryptophan degradation (via the kynurenine pathway; LFC 13; 95%CI: 8–19; p<0.0005) and cresol degradation (LFC 19; 95%CI: 13–25; p<0.0001) pathways were enriched for MS cases vs controls. Differences by DMD status were also observed, e.g., choline biosynthesis was enriched in DMD exposed vs naïve MS cases (LFC 21; 95%CI: 12–29; p<0.0001).

Conclusions

We observed differences in the functional potential of the gut microbiome of young individuals with MS relative to controls at various metabolic pathways, including enrichment of pathways related to tryptophan and metabolism of industrial chemicals. DMD exposure affected findings, with enrichment of pathways involved in promoting CNS remyelination (e.g., choline).

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Presenter Of 1 Presentation

Invited Presentations Invited Abstracts

PL01.01 - The MS Prodrome

Speakers
Authors
Presentation Number
PL01.01
Presentation Topic
Invited Presentations
Lecture Time
09:00 - 09:45

Abstract

Abstract

Historically, a prodromal period in multiple sclerosis (MS) was not thought to exist. A prodrome can be defined as an early set of signs or symptoms occurring before classical onset of a disease. For a chronic neurological disease such is MS, a prodromal phase could span months or years before ‘MS symptom onset.’ While prodromal phases have been relatively well recognized in other neurological conditions, such as Parkinson disease, the MS prodrome has received little consideration until recently. A better understanding of the MS prodrome could have profound implications for disease prevention and management. Thus, it is important for scientists across all disciplines, from bench researchers to epidemiologists, medical ethicistic, and clinical trialists, as well as clinicians, to be cognizant of this emerging area. However, although the field remains nascent, there is sufficient knowledge of the MS prodrome to affect current practice now, particularly research into risk factors for MS onset. Putative risk factors must be carefully evaluated in light of the MS prodrome. However, much more work is needed before the MS prodrome has direct application to routine clinical practice.

Session Objectives: To summarize and reflect on what is currently known, and not known, about the MS prodrome, and what the implications are for research and future clinical care of person’s with MS.

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Invited Speaker Of 1 Presentation

Invited Presentations Invited Abstracts

PL01.01 - The MS Prodrome

Speakers
Authors
Presentation Number
PL01.01
Presentation Topic
Invited Presentations
Lecture Time
09:00 - 09:45

Abstract

Abstract

Historically, a prodromal period in multiple sclerosis (MS) was not thought to exist. A prodrome can be defined as an early set of signs or symptoms occurring before classical onset of a disease. For a chronic neurological disease such is MS, a prodromal phase could span months or years before ‘MS symptom onset.’ While prodromal phases have been relatively well recognized in other neurological conditions, such as Parkinson disease, the MS prodrome has received little consideration until recently. A better understanding of the MS prodrome could have profound implications for disease prevention and management. Thus, it is important for scientists across all disciplines, from bench researchers to epidemiologists, medical ethicistic, and clinical trialists, as well as clinicians, to be cognizant of this emerging area. However, although the field remains nascent, there is sufficient knowledge of the MS prodrome to affect current practice now, particularly research into risk factors for MS onset. Putative risk factors must be carefully evaluated in light of the MS prodrome. However, much more work is needed before the MS prodrome has direct application to routine clinical practice.

Session Objectives: To summarize and reflect on what is currently known, and not known, about the MS prodrome, and what the implications are for research and future clinical care of person’s with MS.

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Author Of 3 Presentations

Biomarkers and Bioinformatics Poster Presentation

P0171 - The gut mycobiome in pediatric multiple sclerosis: establishing a bioinformatics pipeline (ID 876)

Speakers
Presentation Number
P0171
Presentation Topic
Biomarkers and Bioinformatics

Abstract

Background

Studies examining the role of the microbiota in multiple sclerosis (MS) often focus on the gut bacteria; few have considered a potential role of gut mycobiota. Methods for evaluating gut mycobiota are lacking and require systematic evaluation of sequencing protocols, reference databases, and bioinformatics pipelines to properly investigate possible gut mycobiome influences on MS.

Objectives

We set out to evaluate the performance of different sequencing conditions and analytical approaches for characterizing the gut mycobiome in a cohort of healthy individuals and cases with monophasic acquired demyelinating syndrome (mono ADS) or pediatric-onset MS.

Methods

We first assessed a mock-community control pool of known, staggered quantities of 19 defined fungal organisms. We then assessed 201 stool samples obtained from our cohort of 52 healthy individuals, 49 individuals with mono ADS, and 46 participants with pediatric-onset MS. The fungal internal transcribed spacer (ITS) 2 region was sequenced using the Illumina® MiSeq platform. Varying concentrations of PhiX Control v3 Library spike-in were tested to address low-complexity amplicon sequencing. Generated sequences were characterized by the UNITE database—a curated collection of eukaryotic ITS sequences—in conjunction with three distinct fungal sequence analysis pipelines: LotuS, mothur, and PIPITS.

Results

Taxa identified in our mock-community differed across sequencing conditions but were similar between technical replicates. LotuS correctly classified 7 taxa at species-level, 7 taxa at genus-level, whereas 5 remained unclassified. Mothur correctly identified 5 species-level taxa, 11 genus-level taxa, whereas 3 remained unclassified. Lastly, PIPITS correctly identified only 3 species-level taxa, 12 genus-level, while 4 remained unclassified. We successfully generated sequence data for 112 of 147 (76%) individuals (70 females; 42 males). The mean age at stool sample collection was 17.3 (SD 5.1) years. Of the tested sequencing conditions, a spike-in of 50% PhiX produced the highest-quality reads.

Conclusions

The LotuS pipeline best identified fungal taxa in our mock-community, with optimal resolution to species level. Sequencing read quality was optimal when 50% PhiX was used for sequencing ITS2 amplicon libraries of stool samples. Establishment of this validated sequencing pipeline, confirmed using a mock-community with known fungal identities, will aid characterization of gut mycobiomes for our cohort of individuals with/without pediatric-onset MS.

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Disease Modifying Therapies – Risk Management Poster Presentation

P0388 - Safety of dimethyl fumarate for multiple sclerosis: A systematic review and meta-analysis (ID 255)

Speakers
Presentation Number
P0388
Presentation Topic
Disease Modifying Therapies – Risk Management

Abstract

Background

The safety profile of dimethyl fumarate (DMF) used in the treatment of multiple sclerosis (MS) is not fully understood.

Objectives

The objective of this study was to systematically review the literature for adverse events (AE) associated with DMF for MS.

Methods

We searched MEDLINE, EMBASE, CINAHL, Web of Science, CENTRAL, and clinicaltrials.gov for articles published from database inception to May/2019. Studies (observational and randomized controlled trials (RCTs)) reporting AEs, serious AEs (SAE), or discontinuation due to AEs were included. We summarized the proportion of DMF-exposed patients affected and calculated the risk ratios (RR) and number needed to treat for an additional harmful outcome (NNTH) and 95% confidence intervals (CI) for the DMF relative to placebo-exposed participants. RCT findings were pooled via meta-analyses.

Results

Twenty-one observational studies, 4 RCTs, 1 RCT extension study, and 2 open-label studies were included, totalling 12,380 MS patients on DMF followed for an average of 19.8 months. Compared to placebo, DMF-exposed patients had a higher risk of grade III/IV lymphopenia (NNTH=28.8;95%CI:20.2-50.5), pruritus (NNTH=22.1;95%CI:14.0-52.3), flushing (NNTH=3.7;95%CI:3.3-4.1), gastrointestinal related events (NNTH=5.7;95%CI:3.5-15.7), nausea (NNTH=23.4;95%CI:14.9-54.7), diarrhea (NNTH=21.2;95%CI:13.6-47.6), and abdominal pain (NNTH=19.2;95%CI:12.9-37.9). Patients discontinued DMF because of GI symptoms (498/5619;8.9%), lymphopenia (163/4003;4.1%), and flushing (173/4779;3.6%). From pooled analyses of 4 RCTs, AE risks were higher in the DMF versus placebo groups (RR=1.37;95%CI:1.27-1.48), but SAEs were similar (RR=1.01;95%CI:0.77-1.33).

Conclusions

Over the short-term, DMF was associated with a higher risk of AEs. The NNTH included 4 for flushing, 6 for gastrointestinal complaints, and 29 for severe or life-threatening (grade III/IV) lymphopenia. The longer-term safety of DMF, including consequences of lymphopenia remain unknown.

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Epidemiology Poster Presentation

P0443 - Characteristics of a population exposed to a disease-modifying drug for multiple sclerosis in the real-world setting (1996-2017) (ID 200)

Speakers
Presentation Number
P0443
Presentation Topic
Epidemiology

Abstract

Background

The efficacy of a disease-modifying drug (DMD) is typically established via brief clinical trials in highly selected groups. However, in clinical practice, DMDs are used for many years in a more diverse population of persons with multiple sclerosis (MS).

Objectives

The aim of the study was to describe the characteristics of a population with MS who are exposed to their first DMD in the real-world setting.

Methods

Using linked population-based health administrative data, we identified all individuals with MS aged 18 years who filled a prescription for a MS DMD in the province of British Columbia, Canada between 1996 and 2017. Individuals were followed from their first recorded demyelinating event to the earliest of death, emigration from the province, or study end (December 2017). We summarized cohort characteristics at their first filled DMD prescription (sex, age, socioeconomic status) and over the preceding year (comorbidity burden measured by the Charlson Comorbidity Index [CCI]).

Results

Overall, 4283 with MS filled a DMD prescription during the study period. Most were women (n=3132, 73%), with a mean (SD) age at the time of the first DMD prescription fill of 39.9 (9.9) years, and the socioeconomic status was distributed evenly across the income-based quintiles (neighborhood-level). Seventeen percent (n=741) had a CCI score 1. The most prevalent comorbidity was chronic pulmonary disease (n=235, 5%), followed by cerebrovascular disease (n=157, 4%) and diabetes (n=128, 3%). At the first DMD prescription fill, the proportion of women ranged from 63% (n=177/282) for dimethyl fumarate to 83% (n=15/18) for fingolimod. The mean (SD) age at first DMD prescription fill ranged from 37.2 (10.0) years for alemtuzumab to 43.0 (10.6) years for teriflunomide. Nearly 20% (n=724) were 50 years of age when they filled their first DMD prescription and 3% (n=108) were 60 years of age. From 1996-2012, the most common first DMD prescription filled was for either beta-interferon (n=2548/3190, 80%) or glatiramer acetate (n=612/3190, 19%). From 2013-2017, the most common first DMD prescription filled was for glatiramer acetate (n=379/1093, 35%), dimethyl fumarate (n=282/1093, 26%) or teriflunomide (n=182/1093, 17%).

Conclusions

Almost 1 in 5 persons with MS had at least some comorbidity at the time of initiation of their first DMD, while a minority were 60 years of age. As these individuals are often excluded from clinical trials, our data show an unmet need to understand the harms and benefits of DMD use in these understudied groups.

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Presenter 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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