Similar alpha-Synuclein staining in the colon mucosa in patients with Parkinson's disease and controls.

BACKGROUND: The gut is proposed as a starting point of idiopathic IPD, but the presence of alpha-synuclein in the IPD colon mucosa is debated. OBJECTIVES: The objective of this study was to evaluate if alpha-synuclein in the colon mucosa can serve as a biomarker of IPD. METHODS: Immunohistochemistry was used to locate and quantify in a blinded approach alpha-synuclein in the mucosa from biopsies of the right and left colon in 19 IPD patients and 8 controls. RESULTS: Total alpha-synuclein was present in all but 1 IPD patients and in all controls; phosphorylated alpha-synuclein was present in all subjects. There was no intensity difference depending on disease status. Staining of total alpha-synuclein was stronger in the right colon (p = .04). CONCLUSIONS: Conventional immunohistochemistry alpha-synuclein staining in colon mucosal biopsies cannot serve as a biomarker of idiopathic PD. These findings do not contradict the assumption of disease starting in the colon, and a colon segment-specific risk for disease initiation can still be hypothesized. (c) 2016 International Parkinson and Movement Disorder Society.