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Plasma alpha synuclein (a‐syn) as a potential biomarker of diseases with synucleinopathy
Author(s) -
Senanarong Vorapun,
Wachirutmangur Lertchai,
Rattanabunnakit Chatchawan,
Srivanitchapoom Prachaya,
Udomphanthurak Suthipol
Publication year - 2020
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.044409
Subject(s) - medicine , dementia with lewy bodies , biomarker , gastroenterology , cerebrospinal fluid , dementia , parkinson's disease , percentile , alpha synuclein , endocrinology , alzheimer's disease , pathology , disease , chemistry , biochemistry , statistics , mathematics
Background Alpha‐synuclein (a‐syn) is present in red blood cells, cerebrospinal fluid (CSF), plasma and saliva, in both monomeric and oligomeric forms. Alterations in a‐syn levels in CSF and plasma of Parkinson disease (PD) patients have claimed to be potential PD biomarkers. We explored that a‐syn in plasma was a potential biomarker for synucleinopathy diseases Method a‐syn levels in plasma from 54 Parkinson disease dementia (PDD) and dementia with Lewy bodies (DLB) patients (28 men), 31 Alzheimer disease dementia (AD) (16 men), and 28 controls (3 men) were measured by enzyme‐linked immunosorbent assay (ELISA). Result The mean(SD) age of synucleinopathy group, AD group, and normal controls was 72.70(7.72), 74.26(10.37), 62(10.68) (ANOVA test, p<0.001) We showed that the 50 th percentile levels of a‐syn were 9.72 ng/ml, 16.78 ng/ml, 16.75 ng/ml in synucleinopathy group, AD group, and normal controls respectively (p<0.001 by Shapiro‐Wilk test of normality in each group). Pairwise comparisons of group diagnosis revealed that between PDD+DLB vs controls: test statistic ‐16.67, SE 7.63, SD ‐2.19, p=0.03; between PDD+DLB vs AD: test statistic 17.21, SE 7.38, SD 2.33, p=0.02; and between controls vs AD: test statistic 0.63, SE 8.54, SD 0.06, p=0.95. The means plasma a‐syn levels in synucleinopathy group (n=54), AD (n=31) group, and controls (n=29) were 21.89(38.84), 38.45(47.79), 34.02(43.97) ng/ml accordingly (ANOVA test, p=0.18). The levels in synucleinopathy group were lower than those in AD and controls. There was a fair correlation between levels of plasma a‐syn and sum of UPDRS part3 (spearman correlation coefficience r=‐0.32, p=0.008) but not with cognition measured by Addenbrook scale. When eliminating the outliers, the area under the receiver operating characteristic curve (ROCwas 0.710 between PDD+DLB vs non synucleinopathy group (AD+NC) (SE=0.052, p=<0.001). At the cut off levels of 11.4 ng/ml indicated sensitivity of 58%(95%CI 43.21%‐71.81%), specificity of 84.78%(95%CI 71.13%‐93.66%), positive predictive value (PPV) of 80.56%, negative predictive value(NPV) of 65%, and accuracy of 70.83%. Conclusion The present results suggested that plasma a‐syn could be a potential biomarker for synuclienopathy diseases.