Abstract 5- 1300-1315
Category: Basic Science

At the end of the session,
participants will be able to:

  1. Introduce a computer-based method for the morphometric evaluation of alpha-synuclein inclusions in Multiple System Atrophy (MSA) brains.
  2. Demonstrate variability in size and number of alpha-synuclein inclusions across brain regions in MSA cases.
  3. Understand the notion of distinct subtypes of disease in MSA brains

 

Presenter

Dr. Ain Kim is a graduate student at the University of Toronto, Department of Laboratory Medicine and Pathobiology. She received her Honors Bachelor of Science in Neuroscience and Cell & Molecular Biology at University of Toronto and is continuing her research career in the Kovacs lab. Her project aims to evaluate whether the cell type-specific accumulation of alpha-synuclein influences its pathogenicity in the human brain, using seeded amplification assays like the real-time quaking-induced conversion. Additionally, she has developed an AI-based evaluation strategy to measure the size and detectability of oligodendrocytic inclusions that can be further applied to different neuropathological cases. 

Authors

Ain Kim1,2,3, Ivan Martinez-Valbuena2,3, Gabor G. Kovacs1,2,3*.

1Department of Laboratory Medicine & Pathobiology, University of Toronto, Ontario, Canada

2Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, Ontario, Canada

3Krembil Research Institute, University Health Network, Ontario Canada

Target Audience:
Pathologists

CanMEDS:
Scholar

Regional Variability of a-Synuclein Inclusion Size in Multiple System Atrophy

Abstract

Relevance: Multiple system atrophy (MSA) patients show variable duration of illness and distinct constellation of clinical symptoms suggestive of different pathological a-synuclein strains.

Objective: Based on this, our aim is to investigate whether the seeding and aggregation process of a-synuclein are different in MSA brains, leading to variability of size and detectability of oligodendrocytic inclusions using different anti-a-synuclein antibodies.

Methods: The putamen and cerebellum of 6 MSA cases were immunostained using nitrated, truncated, phosphorylated and disease-specific a-synuclein (clone 5G4) antibodies. Sections were scanned using TissuescopeTM and images were processed using Photoshop (v.21.0.3). 5G4-immunoreactive oligodendrocytes with visible nucleus were optically dissected and inclusion sizes were evaluated using algorithms that we developed using the software Image J.

Results: The size of 5G4-reactive inclusions were significantly larger in the cerebellum than in the putamen in 4 out of 6 cases. In one case, the inclusion size was significantly larger in the putamen than in the cerebellum, while a single case showed similar sizes. In addition, case-wise comparison revealed significant variability between the size of inclusions in both regions. In addition, substantial differences were noted between the number of inclusions stained by the different a-synuclein antibodies.

Conclusions: We developed a novel computer-based method to measure the size and number of a-synuclein inclusions in MSA. Our observations on the variability of size and number of inclusions, detected by different a-synuclein epitopes between brain regions and cases, support the notion of distinct subtypes of disease. Our study further provides a first step to developing AI-based evaluation strategies for large scale comparative studies.