Sensitivity of Detecting Alpha-Synuclein Accumulation in the Gastrointestinal Tract and Tissue Volume Examined

Objective This study aimed to evaluate whether a larger tissue volume increases the sensitivity of detecting alpha-synuclein (AS) pathology in the gastrointestinal (GI) tract.Methods Nine patients with Parkinson’s disease (PD) or idiopathic rapid eye movement sleep disorder (iRBD) who underwent GI operation and had full-depth intestinal blocks were included. All patients were selected from our previous study population. A total of 10 slides (5 serial sections from the proximal and distal blocks) per patient were analyzed.Results In previous studies, pathologic evaluation revealed phosphorylated AS (+) in 5/9 patients (55.6%) and in 1/5 controls (20.0%); in this extensive examination, this increased to 8/9 patients (88.9%) but remained the same in controls (20.0%). The severity and distribution of positive findings were similar between patients with iRBD and PD.Conclusion Examining a large tissue volume increased the sensitivity of detecting AS accumulation in the GI tract.