Enteric alpha-synuclein expression is increased in Parkinson's disease but not Alzheimer's disease
Funding agencies: This study was funded by the Department of Laboratory Medicine at St. Michael's Hospital (Toronto, Ontario, Canada).
Relevant Conflicts of Interest/Financial Disclosures: Dr. Munoz has received speaker honoraria from Novartis and Janssen, not related to the research reported here.
Full financial disclosures and author roles may be found in the online version of this article.
Background and Objective
Alpha-synuclein (α-Syn) is immunohistochemically detectable in enteric neurons in some subjects. We determined its age distribution in the general autopsy population and in an age-matched subset investigated differences with Parkinson's (PD) and Alzheimer's diseases (AD).
Archival autopsy samples of colon from 95 cases (77 general population, 10 PD, and 8 AD) were immunostained with monoclonal antibody KM51. α-Syn detectability was semiquantitatively graded 1 to 3.
α-Syn was detectable in 52% of the general population, and its level of expression did not change between ages 40 and 91. All PD subjects were α-Syn positive, with higher prevalence (P = 0.001) and grade (P = 0.003) than age-matched controls. AD subjects were no more likely to be α-Syn positive or have a higher grade than controls.
Either PD develops selectively in the enterically α-Syn-positive population subset or PD induces this expression. Absence of increased α-Syn expression in AD points to differences in pathogenesis. © 2013 Movement Disorder Society