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  • Associations of Cerebrospinal Fluid Orexin-A, Alzheimer Disease Biomarkers, and Cognitive Performance. Annals of clinical and translational neurology Lu, R., Shah, K., Toedebusch, C. D., Hess, A., Richardson, R., Mignot, E., Schindler, S. E., Benzinger, T. L., Flores, S., Hassenstab, J., Xiong, C., Morris, J. C., Holtzman, D. M., Lucey, B. P. 2025

    Abstract

    Cerebrospinal fluid (CSF) orexin-A has been suggested to be a biomarker of Alzheimer disease (AD). In both cognitively unimpaired healthy older adults and individuals with symptomatic AD, CSF orexin-A is positively associated with CSF Aβ42, p-tau181, and total tau (t-tau) concentrations. However, a recent systematic review and meta-analysis did not support differences in orexin-A between AD and controls. In this study, we tested the association between CSF orexin-A concentrations, AD biomarkers, and cognitive performance in older adults with and without symptomatic AD.Two hundred and seventy community-dwelling older adults underwent standardized cognitive assessments, sleep monitoring with a single-channel electroencephalography test, one night of home sleep apnea testing, biofluid and imaging AD biomarker measurement within 1 year of sleep monitoring, and APOE genotyping. Plasma and CSF AD biomarkers were measured by immunoassay or mass spectrometry. CSF orexin-A was measured by radioimmunoassay.CSF orexin-A levels did not differ by amyloid positivity, cognitive status, or AD stage. However, CSF AD biomarkers (Aβ40, Aβ42, and t-tau) were positively associated with CSF orexin-A levels even after correction for multiple comparisons. CSF orexin-A was not associated with any measure of cognitive performance.This study showed that CSF orexin-A is associated with multiple CSF AD biomarkers, but not with AD pathology or cognitive performance. We hypothesize that this is due to similar mechanisms of production/release of these proteins with sleep-wake activity. Future studies measuring other forms of orexin peptides, such as orexin-B, may provide evidence for orexin as a marker for AD.

    View details for DOI 10.1002/acn3.70009

    View details for PubMedID 39957622