Cerebrospinal Fluid Apolipoprotein E Levels in Delirium.

Area of Science:

• Neuroscience
• Biochemistry
• Geriatrics

Background:

• Delirium and the apolipoprotein E ε4 allele are established risk factors for late-onset Alzheimer disease (LOAD).
• The precise mechanistic link between delirium and LOAD risk remains unclear.
• Investigating shared biological pathways is crucial for understanding LOAD pathogenesis.

Purpose of the Study:

• To investigate the association between delirium and apolipoprotein E (ApoE) levels in cerebrospinal fluid (CSF).
• To explore whether reduced ApoE levels during delirium could represent a mechanistic link to LOAD risk.

Main Methods:

• Comparison of inpatients with delirium (n=18) and outpatients with LOAD (n=19).
• Assay of blood and CSF samples using multiplex ELISA to measure various apolipoproteins.
• Correlation analysis between ApoE levels, delirium severity scores (CAM, Delirium Index), and cognitive function (MMSE).

Main Results:

• Patients with delirium exhibited significantly higher Confusion Assessment Method (CAM) and Delirium Index scores, and lower Mini-Mental State Examination (MMSE) scores compared to LOAD patients.
• A significant reduction in absolute CSF apolipoprotein E levels was observed during delirium.
• CSF apolipoprotein E levels correlated negatively with delirium severity scores (CAM and Delirium Index).

Conclusions:

• Reduced CSF apolipoprotein E levels during delirium episodes may serve as a mechanistic link between delirium and the risk of developing late-onset Alzheimer disease.
• These findings highlight the potential role of ApoE in the neurobiological processes connecting delirium and LOAD.