Objective: This study aimed to verify whether evaluation of extensive tissue volume increases sensitivity of detecting alpha-synuclein (AS) pathology in the gastrointestinal (GI) tract in patients with synucleinopathy.

Background: The AS pathology of the GI tract has the potential to be used as a biomarker, but low sensitivity makes it difficult to be used practically. In previous autopsy studies, there was a report that evaluation of multiple section increased the positive rate, and earlier in vivo studies reported high sensitivity using a method called ‘whole mount staining’. Therefore,

Method: The study population was the patients with Parkinson’s disease (PD) and idiopathic rapid eye movement sleep disorder (iRBD) who were included in our previous two studies. We selected 9 patients whose proximal and distal full-depth intestinal blocks were present. In the original studies, positive findings were showed in 5 PD/iRBD patients (55.6%). In addition, 5 subjects were selected from the control group. A total 10 slides (5 serial sections from proximal or distal block each) per patient were analyzed.

Results: In this extensive evaluation, positive findings were found in 8 patients (88.9%) except 1 patient with iRBD. Positive findings were observed in all 5 slides per block in 80% and in both proximal and distal blocks in 66.7% of the 8 patients with AS positivity. In all 3 patients with AS positive findings in only one block (either distal or proximal), mild positive AS pathology (1+ in the semi-quantitative grade) was found.

Conclusion: Extensive tissue volume increases sensitivity of AS pathology in the GI tract. This study suggests that at least 2 serial slides of the full-depth surgical specimen per area are necessary to accomplish optimal sensitivity in the GI tract.

« Back to MDS Virtual Congress 2021

MDS Abstracts - https://www.mdsabstracts.org/abstract/extensive-volume-increases-sensitivity-of-alpha-synuclein-accumulation-in-the-gastrointestinal-tract/