Increased plasma neurofilament light chain concentration correlates with severity of post-mortem neurofibrillary tangle pathology and neurodegeneration

• Published in: Acta neuropathologica communications Vol. 7; no. 1; p. 5
• Main Authors: Ashton, Nicholas J, Leuzy, Antoine, Lim, Yau Mun, Troakes, Claire, Hortobágyi, Tibor, Höglund, Kina, Aarsland, Dag, Lovestone, Simon, Schöll, Michael, Blennow, Kaj, Zetterberg, Henrik, Hye, Abdul
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 09-01-2019; BioMed Central; BMC
• Subjects: Advertising executives; Aged; Aged, 80 and over; Alzheimer Disease - blood; Alzheimer Disease - pathology; Alzheimer Disease - psychology; Alzheimer's disease; Biological markers; Biomarkers; Blood biomarkers; Braak; Brain - pathology; Brain research; Clinical Medicine; Clinical trials; Comparative analysis; Dementia; EDTA; Female; HIV; Human immunodeficiency virus; Humans; Immunology; Klinisk medicin; Light; Longitudinal Studies; Male; Medical and Health Sciences; Medical imaging; Medicin och hälsovetenskap; Nervous system; Neurodegeneration; Neurofibrillary Tangles - pathology; Neurofilament light chain; Neurofilament Proteins - blood; Neurologi; Neurology; Neurons; Neuropathology; Neurosciences; Neurovetenskaper; Pathology; Plasma; Post-mortem; Proteins; Tau; Neurofilament light chain; Post-mortem; Tau; Braak; Blood biomarkers
• ISSN: 2051-5960; 2051-5960
• DOI: 10.1186/s40478-018-0649-3

Alzheimer's disease (AD) is pathologically characterized by the accumulation of amyloid-β (Aβ) plaques, neurofibrillary tangles and widespread neuronal loss in the brain. In recent years, blood biomarkers have emerged as a realistic prospect to highlight accumulating pathology for secondary prevention trials. Neurofilament light chain (NfL), a marker of axonal degeneration, is robustly elevated in the blood of many neurological and neurodegenerative conditions, including AD. A strong relationship with cerebrospinal fluid (CSF) NfL suggests that these biomarker modalities reflect the same pathological process. Yet, the connection between blood NfL and brain tissue pathology has not been directly compared. In this study, longitudinal plasma NfL from cognitively healthy controls (n = 12) and AD participants (n = 57) were quantified by the Simoa platform. On reaching post-mortem, neuropathological assessment was performed on all participants, with additional frozen and paraffin-embedded tissue acquired from 26 participants for further biochemical (Aβ
, Aβ
, tau) and histological (NfL) evaluation. Plasma NfL concentrations were significantly increased in AD and correlated with cognitive decline, independent of age. Retrospective stratification based on Braak staging revealed that baseline plasma NfL concentrations were associated with higher neurofibrillary tangle pathology at post-mortem. Longitudinal increases in plasma NfL were observed in all Braak groupings; a significant negative association, however, was found between plasma NfL at time point 1 and both its rate of change and annual percentage increase. Immunohistochemical evaluation of NfL in the medial temporal gyrus (MTG) demonstrated an inverse relationship between Braak stages and NfL staining. Importantly, a significant negative correlation was found between the plasma NfL measurement closest to death and the level of NfL staining in the MTG at post-mortem. For the first time, we demonstrate that plasma NfL associates with the severity of neurofibrillary tangle pathology and neurodegeneration in the post-mortem brain.