Review Article

Alpha-Synuclein in Parkinson’s Disease: From Pathogenetic Dysfunction to Potential Clinical Application

Table 1

Selected studies targeting α-synuclein as biomarker for the diagnosis of PD.

RefMaterialsAnalytical/measuring methodsResults in PD patients compared to controls

Lebouvier et al., 2008 [84]Colonic tissueBiopsy and immunohistochemical studiesTH-IR (tyrosine-hydroxylase immunoreactive) neurons were not a marker but phospho-α-synuclein-IR neurities were found in PD patients
Beach et al., 2010 [75]Lower esophagus and submandibular tissueBiopsy and a sensitive immunohistochemical method for phosphorylated α-synucleinA rostrocaudal gradient of decreasing phosphorylated α-synuclein histopathology frequency and density
Shi et al., 2010 [45]Alpha-synuclein in plasmaBlood component separation and analysisNo statistical difference was observed
Cersósimo et al., 2011 [85]Salivary glandBiopsy and immunohistochemical studiesThe presence of α-synuclein inclusions in the submandibular glands
Devic et al., 2011 [76]SalivaImmunoblotting with a rabbit anti-human α-synuclein antibody ASY-1The level of α-synuclein decreased
Yanamandra et al., 2011 [77]Alpha-synuclein reactive antibodies in blood seraELISA, western blot, and Biacore surface plasmon resonanceHigher antibody levels towards monomeric α-synuclein
Shannon et al., 2012 [86]Colonic submucosaBiopsy and immunohistochemical studiesStaining for α-synuclein in nerve fibers in colonic submucosa
Alexoudi et al., 2013 [87]Submandibular glandTopic discussionPositive
Schmid et al., 2013 [88]Alpha-synuclein posttranslational modifications (PTMs)A new chemical synthesis schemeRelevant PTMs associated with disease progression and severity
Adler et al., 2014 [89]Submandibular glandBiopsy and immunohistochemical studiesMicroscopic evidence of the tissue was positive for Lewy type α-synucleinopathy
Gao et al., 2015 [46]CSFMeta-analysisThe mean CSF α-synuclein concentration was significantly lower
Sanchez-Ferro et al., 2015 [90]Gastric mucosa samplesBiopsy and immunohistochemical studiesPositive fibers for the α-synuclein protein were observed
Zhou et al., 2015 [73]CSFMeta-analysisMean concentration of CSF α-synuclein was slightly decreased; mean concentration of CSF α-synuclein oligomers was significantly higher
Adler et al., 2016 [91]Submandibular glandBiopsy and immunohistochemical studiesPositive staining
Donadio et al., 2016 [83]Skin nerveSkin biopsyOnly 49% of samples with a higher positivity rate for abnormal α-synuclein deposits at the proximal site in IPD
Parnetti et al., 2016 [74]CSFReview of 32 selected articlesThe role of α-synuclein species in PD prognosis remained unsatisfactory