The use of serum neurofilament light (NfL) has been identified as a promising biomarker of primary and secondary neuroaxonal injury after ischemic stroke (IS), according to the results of a prospective cohort study published in Neurology. Between February 2014 and March 2017, a total of 277 patients with suspected IS within 24 hours of symptom onset were evaluated through the Circulating Biomarkers in Acute Stroke study, with recruitment from the emergency department of the tertiary level university hospital at Ludwig-Maximilians University in Munich, Germany.
The investigators sought to examine the use of NfL as a biomarker for neuroaxonal injury after IS and to explore its value with respect to the prediction of clinical outcome. They used an ultrasensitive single-molecule array assay to calculate serum NfL levels in a total of 30 healthy control participants and in 2 independent cohorts of patients with IS: patients with serum sampling on hospital arrival (n=196); at days 2, 3, and 7 (n=89); and up to 6 months poststroke (n=11) and patients with standardized magnetic resonance imaging (MRI) at baseline, at 6 months poststroke, and with cross-sectional serum sampling at 6 months (German Center for Neurodegenerative Disease-Mechanisms of Dementia After Stroke) (n=95).
Results of the analysis showed that patients with IS had higher serum NfL levels compared with healthy control participants, beginning from hospital admission until 6 months poststroke. Serum NfL levels peaked at day 7 (211.2 pg/mL) and correlated with volume of infarcts (day 7: partial r =0.736; P =1.5 × 10−15). At 6 months poststroke, patients who had recurrent ischemic lesions on MRI (n=19) exhibited significantly higher serum NfL levels than patients without any new ischemic lesions (n=76; P =.002).
Serum NfL levels 6 months after stroke were also significantly associated with a quantitative measure of secondary neurodegeneration according to diffusion tensor imaging MRI (r =0.361; P =.001). At 7 days poststroke, serum NfL levels independently predicted modified Rankin score at 6 months poststroke (cumulative odds ratio, 2.35; 95% CI, 1.60-3.45; P =1.24 × 10−5).
The investigators identified serum NfL levels after IS as a promising biomarker for the prediction of functional outcome among patients. As serum NfL levels reflect, in part, neuroaxonal degeneration of white matter tracts after acute ischemic infarcts, these levels seem appropriate to monitor multiple aspects of disease activity among patients with vascular brain lesions.
Tiedt S, Duering M, Barro C, et al. Serum neurofilament light: a biomarker of neuroaxonal injury after ischemic stroke. Neurology. 2018;91(14):e1338-e1347.