Validation of Serum Neurofilament Light Chain as a Biomarker of Parkinson's Disease Progression

Abstract

Background: The objective of this study was to assess neurofilament light chain as a Parkinson's disease biomarker.

Methods: We quantified neurofilament light chain in 2 independent cohorts: (1) longitudinal cerebrospinal fluid samples from the longitudinal de novo Parkinson's disease cohort and (2) a large longitudinal cohort with serum samples from Parkinson's disease, other cognate/neurodegenerative disorders, healthy controls, prodromal conditions, and mutation carriers.

Results: In the Parkinson's Progression Marker Initiative cohort, mean baseline serum neurofilament light chain was higher in Parkinson's disease patients (13 ± 7.2 pg/mL) than in controls (12 ± 6.7 pg/mL), P = 0.0336. Serum neurofilament light chain increased longitudinally in Parkinson's disease patients versus controls (P < 0.01). Motor scores were positively associated with neurofilament light chain, whereas some cognitive scores showed a negative association.

Conclusions: Neurofilament light chain in serum samples is increased in Parkinson's disease patients versus healthy controls, increases over time and with age, and correlates with clinical measures of Parkinson's disease severity. Although the specificity of neurofilament light chain for Parkinson's disease is low, it is the first blood-based biomarker candidate that could support disease stratification of Parkinson's disease versus other cognate/neurodegenerative disorders, track clinical progression, and possibly assess responsiveness to neuroprotective treatments. However, use of neurofilament light chain as a biomarker of response to neuroprotective interventions remains to be assessed. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Keywords: Parkinson's disease/parkinsonism; cohort studies; outcome research.

FIG. 1.

(a) Log2-transformed CSF NfL levels at each visit in healthy controls (HCs), Parkinson’s disease (PD), other neurodegenerative disorders (OND), in the DeNoPa cohort (demographics in Supplementary Table e1). The gray ribbon provides estimates of the standard error. (b) Spearman’s correlation of CSF and serum NfL in the bridging cohort (demographics are in Supplementary Table e3). (c) Age- and sex-adjusted log2-transformed serum NfL levels at each visit in HCs, Parkinson’s disease (PD), other neurodegenerative disorders (OND), prodromal with hyposmia or isolated REM sleep behavior disorder (PROD), and the genetic cohort with affected mutation carriers (GC-PD) and unaffected mutation carriers (GC-UN) in the PPMI cohort (demographics in Table 1). The gray ribbon provides estimates of the standard error. [Color figure can be viewed at wileyonlinelibrary.com]