title: Alimentary, my dear Watson? The challenges of enteric α-synuclein as a Parkinson's disease biomarker.
abstract: An accurate early diagnostic test for Parkinson's disease (PD) is a critical unmet need. Recently, independent groups using different histological techniques have reported that the presence of alpha-synuclein (α-syn) in colonic biopsy tissue is able to distinguish living patients with PD from those without the disease. In addition, a further study has suggested that the presence of α-syn in colonic biopsy tissue may be evident in early or even prodromal PD. However, several questions remain regarding the translation of these findings into using the assessment of α-syn deposition in the enteric nervous system as a diagnostic biomarker for prodromal PD. Here we address critical issues related to the location and quantification of enteric α-syn, detection of α-syn with currently available histological techniques, timing of detection of α-syn deposition, and, most crucially, whether enteric α-syn can distinguish those with PD from both healthy individuals and individuals with other related diseases. We conclude that, although enteric α-syn is a very exciting prospect, further studies will be vital to determine whether enteric α-syn deposition has the potential to be the biomarker for prodromal PD that the field so desperately seeks.
authors.affiliation: Morton and Gloria Shulman Movement Disorders Centre and the Edmund J. Safra Program in Parkinson's Disease, Toronto Western Hospital, Toronto, Ontario, Canada.
authors.forename: Naomi P
authors.initials: NP
authors.lastname: Visanji
authors.forename: Connie
authors.initials: C
authors.lastname: Marras
authors.forename: Lili-Naz
authors.initials: LN
authors.lastname: Hazrati
authors.forename: Louis W C
authors.initials: LW
authors.lastname: Liu
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Lang
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D003106:Colon / Q000378:metabolism* / Q000473:pathology; D017615:Enteric Nervous System / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D010300:Parkinson Disease / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D062706:Prodromal Symptoms; D051844:alpha-Synuclein / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D051844:alpha-Synuclein
keywords: Parkinson's disease; alpha-synuclein; biomarker; colon biopsy; enteric nervous system