In Vivo Gastric Detection of α-Synuclein Inclusions in Parkinson’s Disease (P4.049)

Objective: We aimed to assess α-synuclein inclusions in gastric mucosa samples from patients with symptomatic PD and controls. Background: α-Synuclein inclusions, a neuropathological hallmark of Parkinson’s disease (PD), have been in some parts of the enteric nervous system, especially in distal enteric samples (Lebouvier et al 2010) of PD patients. Methods: Random antral and pyloric biopsies were obtained by gastroscopy in 28 patients with advanced PD and in 29 age and gender matched controls. The reasons for the gastroscopy were 1) instauration of enteral L-Dopa therapy among the PD group 2) diagnostic purposes in the control group, being gastro-esophageal reflux, anemia and abdominal pain the main indications. The clinical definition of the cases and controls was made a priori. and in 6 controls, data suggestive of “presymptomatic parkinsonism” were present. Biopsies were immunostained for α-synuclein. The neuropathological diagnosis was established post hoc. Results: There were no differences in the baseline characteristics of the groups. Eight biopsies in the advanced PD group were excluded for technical reasons. Positive fibres for the α-synuclein protein were observed in 17 out of 28 (60.7%) PD patients, 1 out of 23 controls (4.3%), and 1 out of 6 (16.7%) cases of incident “presymptomatic parkinsonism”. Neuropathological diagnosis of PD based on α-synuclein immunostaining showed a sensitivity of 85% (95% confidence interval [CI] 62.1 to 96.8), specificity of 95% (95% CI 76.2 to 99.9) and area under the receiver operating characteristics curve (AUC) of 0.90 (95% CI 0.80 to 1.00). α-Synuclein positive fibres predominated in the pyloric region. No adverse events related to the procedure were recorded. Conclusions: Detection of α-synuclein inclusions in the gastric mucosa is a useful and safe tool providing in vivo evidence of the underlying neurodegenerative peripheral involvement linked to PD. Further studies are warranted to determine its pathophysiological implications, especially in early symptomatic cases and risk groups (familial forms or REM Sleep Behaviour disorder cases). Disclosure: Dr. Sanchez has nothing to disclose. Dr. Rabano has nothing to disclose. Dr. Catalan has nothing to disclose. Dr. Canga has nothing to disclose. Dr. Fernandez-Diez has nothing to disclose. Dr. Herreros-Rodriguez has nothing to disclose. Dr. Garcia-Cobos has nothing to disclose. Dr. Mata Alvarez-Santull has nothing to disclose. Dr. Lopez-Manzanares has nothing to disclose. Dr. Antonio J has nothing to disclose. Dr. Vela has nothing to disclose. Dr. Lopez-Lozano has nothing to disclose. Dr. Lopez-Valdes has nothing to disclose. Dr. Molina has nothing to disclose.