Hypothalamic dysfunction is related to sleep impairment and CSF biomarkers in Alzheimer’s disease

Hypothalamus is a key brain region regulating several essential homeostatic functions, including the sleep–wake cycle. Alzheimer’s disease (AD) pathology affects nuclei controlling sleep–wake rhythm sited in this brain area. Since only post-mortem studies documented the relationship between hypothalamic atrophy and sleep–wake cycle impairment, we investigated in AD patients the possible hypothalamic in vivo alteration using 2-deoxy-2-(18F) fluoro-d-glucose ([18F]FDG) positron emission tomography ([18F]FDG PET), and its correlations with sleep impairment and cerebrospinal-fluid (CSF) AD biomarkers (tau proteins and β-amyloid42). We measured sleep by polysomnography, CSF AD biomarkers and orexin levels, and hypothalamic [18F]FDG PET uptake in a population of AD patients compared to age- and sex-matched controls. We documented the significant reduction of hypothalamic [18F]FDG PET uptake in AD patients (n = 18) compared to controls (n = 18) (p