NEUROBIOLOGY OF DISEASE

Schultz SA, Strain JF, Adedokun A, Wang Q, Preische O, Kuhle J, Flores S, Keefe S, Dincer A, Ances BM, Berman SB, Brickman AM, Cash DM, Chhatwal J, Cruchaga C, Ewers M, Fox NN, Ghetti B, Goate A, Graff-Radford NR, Hassenstab JJ, Hornbeck R, Jack C, Jr., Johnson K, Joseph-Mathurin N, Karch CM, Koeppe RA, Lee AKW, Levin J, Masters C, McDade E, Perrin RJ, Rowe CC, Salloway S, Saykin AJ, Sperling R, Su Y, Villemagne VL, Vöglein J, Weiner M, Xiong C, Fagan AM, Morris JC, Bateman RJ, Benzinger TLS, Jucker M and Gordon BA.

Neurobiol Dis. 2020.

DOI: https://doi.org/10.1016/j.nbd.2020.104960

Abstract

Neurofilament light chain (NfL) is a protein that is selectively expressed in neurons. Increased levels of NfL measured in either cerebrospinal fluid or blood is thought to be a biomarker of neuronal damage in neurodegenerative diseases. However, there have been limited investigations relating NfL to the concurrent measures of white matter (WM) decline that it should reflect. White matter damage is a common feature of Alzheimer’s disease. We hypothesized that serum levels of NfL would associate with WM lesion volume and diffusion tensor imaging (DTI) metrics cross-sectionally in 117 autosomal dominant mutation carriers (MC) compared to 84 non-carrier (NC) familial controls as well as in a subset (N = 41) of MC with longitudinal NfL and MRI data. In MC, elevated cross-sectional NfL was positively associated with WM hyperintensity lesion volume, mean diffusivity, radial diffusivity, and axial diffusivity and negatively with fractional anisotropy. Greater change in NfL levels in MC was associated with larger changes in fractional anisotropy, mean diffusivity, and radial diffusivity, all indicative of reduced WM integrity. There were no relationships with NfL in NC. Our results demonstrate that blood-based NfL levels reflect WM integrity and supports the view that blood levels of NfL are predictive of WM damage in the brain. This is a critical result in improving the interpretability of NfL as a marker of brain integrity, and for validating this emerging biomarker for future use in clinical and research settings across multiple neurodegenerative diseases