Resistance of human cerebrospinal fluid to in vitro oxidation is directly related to its amyloid-β content

Abstract

Amyloid-β (Aβ) peptide, a major constituent of senile plaques and a hallmark of Alzheimer's disease (AD), is normally secreted by neurons and can be found in low concentrations in cerebrospinal fluid (CSF) and plasma where it is associated with lipoproteins. However, the physiological role of Aβ secretion remains unknown. We measured the resistance to in vitro oxidation of CSF obtained from 20 control subjects and 30 patients with AD, and correlated it with CSF levels of antioxidants, lipids and Aβ. We found that the oxidative resistance, expressed as a duration of the oxidation lag-phase, was directly related to CSF levels of Aβ_1-40, Aβ_1-42 and ascorbate and inversely to levels of fatty acids. These data suggest that, besides ascorbate, Aβ is another major physiological antioxidant for CSF lipoproteins.

Keywords:

• Amyloid-β
• Cerebrospinal fluid
• Antioxidants
• Ascorbate
• Lipid peroxidation
• Alzheimer's disease