In vivo and autopsy validation of alpha-synuclein seeding activity using RT-QuIC assay in the gastrointestinal tract of patients with Parkinson's disease

Chaewon Shin, Jung Youn Han, Seong Ik Kim, Sung Hye Park, Han Kwang Yang, Hyuk Joon Lee, Seong Ho Kong, Yun Suhk Suh, Han Joon Kim, Young Pyo Choi, Beomseok Jeon

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: In the present study, real-time quaking-induced conversion (RT-QuIC) assay was used to evaluate pathologic alpha-synuclein (AS) seeding activity in formalin-fixed paraffin-embedded (FFPE) tissue from the gastrointestinal (GI) tract of Parkinson's disease (PD) patients. Methods: This study was conducted in two parts: Part I. a preliminary autopsy study that included four autopsy-confirmed patients with synucleinopathy (2 PD, 1 dementia with Lewy bodies [DLB], and 1 multiple system atrophy [MSA]) and two normal autopsy controls. Frozen and FFPE tissues of the brain were obtained. Part II. a clinical case-control study that included 20 clinically diagnosed PD patients and matched controls. Surgically resected FFPE tissues from the upper and lower GI tracts were used. The RT-QuIC assay was performed to evaluate pathologic seed amplification using frozen or FFPE tissues. The presence or absence of AS aggregation was confirmed by conventional phosphorylated AS (pAS) immunohistochemistry (IHC). Results: In Part I, RT-QuIC assay showed pathologic AS amplification in frozen and FFPE brain tissues of PD and DLB patients, and FFPE stomach tissue of PD patients but not in the MSA patient and controls. In Part II, pathologic seeding activity was found in 10% (2/20) of the stomach tissues of clinical PD patients but in none of the matched controls. IHC showed pAS-positive staining in 55% of patients (11/20) and 15% of controls (3/20). Conclusion: The present study results showed that the RT-QuIC assay using FFPE tissue of the GI tract was inadequate as a biomarker in PD.

Original languageEnglish
Pages (from-to)23-28
Number of pages6
JournalParkinsonism and Related Disorders
Volume103
DOIs
StatePublished - Oct 2022

Keywords

  • Alpha-synuclein
  • Autopsy
  • Gastrointestinal tract
  • Parkinson's disease
  • RT-QuIC

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