Invited Presentations Invited Abstracts

PS03.01 - MRI Phenotypes and miRNA Signatures in MS

  • C. Hemond
  • C. Hemond
  • B. Healy
  • S. Tauhid
  • M. Mazzola
  • F. Quintana
  • R. Gandhi
  • H. Weiner
  • R. Bakshi
Presentation Number
Presentation Topic
Invited Presentations
Lecture Time
10:30 - 10:45



Background: Multiple sclerosis is characterized by both neuroinflammation and accelerated brain atrophy. These two processes can be quantified by MRI, are at least partially independent, and have different underlying pathological mechanisms. MicroRNA (miRNA) have previously shown strong ties to various neurological disease processes, and have potential as biomarkers in MS.

Objectives: To classify and immunologically characterize persons with MS based on serum miRNA profiles in conjunction with MRI phenotypes, as defined by relative burden of cerebral T2-hyperintense lesion volume (T2LV) and brain parenchymal fraction (BPF).

Methods: Cerebral T2LV and BPF were retrospectively quantified from 1.5T MRI, and used to define the following MRI phenotypes. Type I: low T2LV, low atrophy; type II: high T2LV, low atrophy; type III: low T2LV, high atrophy; type IV: high T2LV, high atrophy, in a large cross-sectional cohort (n = 1,088) and a subset with 5-year longitudinal follow-up (n = 153). Serum miRNAs were assessed on a third MS cohort with 2-year MRI phenotype stability (n = 98). A proportional odds logistic regression model was used to determine significant associations been MRI features and miRNA expression.

Results: One-third of the patients showed dissociation between lesion burden and atrophy severity as defined by MRI phenotypes II or III. At 5-year follow-up, all phenotypes showed increased atrophy (p < 0.001), disproportionally in type II (BPF −2.28%). Only type IV experienced significantly worse neurological disability scores. Types I and II had a 5-year MRI phenotype conversion rate of 33% and 46%, whereas III and IV had >90% stability. Type II switched primarily to IV (91%); type I switched primarily to II (47%) or III (37%). Baseline higher age (p = 0.006) and lower BPF (p < 0.001) predicted 5-year phenotype conversion. MicroRNA analysis revealed sixteen miRNA differentially expressed (p < 0.05, uncorrected) between the four phenotypes. Each phenotype demonstrated a distinct miRNA signature. Biological interpretation of these miRNA suggest a role for blood-brain barrier pathology. miR-22-3p, miR-361-5p, and miR-345-5p were the most valid differentiators.

Conclusions: MRI-defined MS phenotypes show high conversion rates characterized by relentless brain atrophy with or without ongoing inflammation, and results support the partial independence of these two features. Differentially expressed serum microRNA for the MRI phenotypes implicates the blood-brain barrier as an important mechanism determining pathological course. MicroRNA are promising as biomarkers in MS but require significant further verification and methodological standardization.