Association between Hypocretin-1 and Amyloid-β42 Cerebrospinal Fluid Levels in Alzheimer’s Disease and Healthy Controls

Title:Association between Hypocretin-1 and Amyloid-β42 Cerebrospinal Fluid Levels in Alzheimer’s Disease and Healthy Controls

Volume: 9 Issue: 10

Author(s): Diane Slats, Jurgen A.H.R. Claassen, Gert Jan Lammers, Rene J. Melis, Marcel M. Verbeek and Sebastiaan Overeem

Affiliation:

Keywords: Amyloid-β, Cerebrospinal fluid, circadian rhythms, hypocretin, neurobiology, peptides, sleep, sleep disturbances

Abstract: Alzheimer’s disease is associated with sleep disorders. Recently, animal studies demonstrated a link between hypocretin, a sleep-regulation neurotransmitter, and AD pathology. In this study, we investigated the circadian rhythm of hypocretin-1 in Alzheimer’s Disease (AD) patients and controls. Moreover, we assessed the relation between CSF hypocretin-1 and amyloid-β. A continuous CSF sampling study via indwelling intrathecal catheter was performed to collect hourly CSF samples of six patients with AD (59-85 yrs, MMSE 16-26) and six healthy volunteers (64-77 yrs). CSF hypocretin-1 and Aβ42 concentrations were determined at 8 individual time points over 24 hours. A circadian pattern was assessed by fitting a 24 hour sine curve to the hypocretin-1 data using mixed model analysis. Clinical diagnosis and Aβ42 were entered into the model as time invariant covariates to determine differences between AD and controls, and correlate Aβ42 to hypocretin-1 levels. A hypocretin-1 circadian rhythm with an amplitude of 11.5 pg/ml was found in clinical AD patients, which did not differ from the control group (7.15 pg/ml). Lower mean CSF Aβ42 levels were related to lower hypocretin-1 levels; 1.6 pg/ml hypocretin-1 per 10 pg/ml Aβ42 (p=0.03), and a higher amplitude of the hypocretin-1 circadian rhythm (0.4 pg/ml, p=0.03). CSF hypocretin-1 has a circadian rhythm for which we could show no difference between AD and controls. However, the association between mean Aβ42 levels and mean hypocretin-1 levels and amplitude may suggest a relationship between AD pathology and hypocretin disturbance, which could hold possibilities for treatment of AD related sleep disorders.

Cite this article as:

Slats Diane, A.H.R. Claassen Jurgen, Jan Lammers Gert, J. Melis Rene, M. Verbeek Marcel and Overeem Sebastiaan, Association between Hypocretin-1 and Amyloid-β42 Cerebrospinal Fluid Levels in Alzheimer’s Disease and Healthy Controls, Current Alzheimer Research 2012; 9 (10) . https://dx.doi.org/10.2174/156720512804142840