The following is a summary of “Analysis of biomarkers in speculative CNS-enriched extracellular vesicles for parkinsonian disorders: a comprehensive systematic review and diagnostic meta-analysis,” published in the December 2023 issue of Neurology by Taha et al.
Despite diverse cellular and regional damage across Parkinson’s disease (PD), multiple system atrophy (MSA), dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP), and corticobasal syndrome (CBS), early symptoms overlap, hindering diagnosis.
Researchers launched a retrospective study to assess whether blood-based analysis of brain-enriched extracellular vesicles could accurately diagnose Parkinsonian disorders.
They conducted a PRISMA-guided systematic review and meta-analysis, encompassing 18 studies, 1695 patients with PD, 253 with MSA, 21 with DLB, 172 with PSP, 152 with CBS, 189 with REM Behavior Disorder (RBD), and 1,288 HCs. Analytical methods included either hierarchical bivariate models or univariate models.
The results showed moderate diagnostic accuracy for distinguishing patients with PD from HCs. However, high heterogeneity and significant publication bias indicated potential inflation of perceived diagnostic effectiveness. The observed bias suggested that studies with non-significant or lower effect sizes were less likely to be published. Although promising for PD versus MSA or PSP and CBS, the validity of results is limited due to the small number of studies from the same research group. Despite initial reports, the analyses suggest that speculative CNS-enriched Extracellular Vesicle (EV) biomarkers may not reliably differentiate MSA or RBD from HCs. This is due to their lesser accuracy and substantial variability among studies, further complicated by significant publication bias.
They concluded that brain-based blood markers in Parkinson’s offered moderate but unreliable diagnosis, calling for better tools and more extensive studies.
Source: springer.com/article/10.1007/s00415-023-12093-3
