Objective: Measures of neuronal damage/dysfunction are likely good surrogates for disease progression in Alzheimer disease (AD). CSF markers of neuronal injury may offer utility in predicting disease progression and guiding prognostic and outcome assessments in therapeutic trials. Visinin-like protein-1 (VILIP-1) has demonstrated potential utility as a marker of neuronal injury. We here investigate the utility of VILIP-1 and VILIP-1/A42 in predicting rates of cognitive decline in early AD.Methods: Individuals with a clinical diagnosis of very mild or mild AD (n ϭ 60) and baseline CSF measures of VILIP-1, tau, p-tau181, and A42 were followed longitudinally for an average of 2.6 years. Annual assessments included the Clinical Dementia Rating (CDR), CDR-sum of boxes (CDR-SB), and global composite scores. Mixed linear models assessed the ability of CSF biomarker measures to predict rates of cognitive decline over time.Results: Baseline CSF VILIP-1 and VILIP-1/A42 levels predicted rates of future decline in CDR-SB and global composite scores over the follow-up period. Individuals with CSF VILIP-1 Ն560 pg/mL (corresponding to the upper tercile) progressed much more rapidly in CDR-SB (1.61 boxes/year; p ϭ 0.0077) and global scores (Ϫ0.53 points/year; p ϭ 0.0002) than individuals with lower values (0.85 boxes/year and Ϫ0.15 points/year, respectively) over the follow-up period. CSF tau, p-tau181, tau/A42, and p-tau181/A42 also predicted more rapid cognitive decline in CDR-SB and global scores over time.
Conclusion:These findings suggest that CSF VILIP-1 and VILIP-1/A42 predict rates of global cognitive decline similarly to tau and tau/A42, and may be useful CSF surrogates for neurodegeneration in early AD. Neurology The aggregation and deposition of amyloid- and tau, the 2 key proteins involved in Alzheimer disease (AD) pathogenesis, are estimated to begin years prior to the onset of cognitive impairment.1,2 However, it is only after a threshold of neuronal loss is reached in vulnerable brain regions that the first signs of cognitive impairment appear. Several lines of evidence suggest that neuronal and synaptic loss is the best surrogate for disease progression and cognitive decline in AD.2,4 While CSF tau and amyloid-beta 1-42 (A42) each predominantly reflect a specific AD pathology, neuronal injury/neurodegeneration likely represents the cumulative outcome of different pathologic substrates. Therefore, CSF markers of neuronal injury, along with CSF tau and A42, may offer utility in predicting disease progression and future cognitive decline in the early stages of disease.