The effect of lumbar puncture on the neurodegeneration biomarker neurofilament light in macaque monkeys.

Neurofilament light (NFL) in cerebrospinal fluid (CSF) is elevated in neurodegenerative disease patients, and may track disease progression and treatment. Macaque monkeys are emerging as important translational models of neurodegeneration, and NFL may be a useful biomarker. To determine the influence of a previous lumbar puncture (LP) on NFL, we collected CSF at multiple time points in macaque monkeys via LP or cisterna magna puncture. NFL, amyloid beta (Aβ40, Aβ42), and tau (tTau, pTau) in CSF were measured by standard enzyme-linked immunosorbent assay and multiplex. NFL was significantly elevated at 14 to 23 days after an LP (median increase: 162%). Aβ and tau biomarkers remained stable. NFL peaked and decayed over 1 to 2 months after LP. NFL was not elevated after cisterna magna puncture. Results suggest damage of the cauda equina during LP may increase NFL. Caution should be taken in interpreting NFL concentration in studies in which repeat LPs are performed.