Cross-Sectional Characterization of Albumin Glycation State in Cerebrospinal Fluid and Plasma from Alzheimer's Disease Patients.

We determined albumin post-translational modifications (PTMs) by mass spectrometry (MS) in plasma and cerebrospinal fluid (CSF) from 31 Alzheimer's disease (AD) patients (with 27 samples of paired plasma-CSF from the same patients). Results were cross-sectionally compared with healthy controls. For percentage of relative intensity of glycated isoforms, plasma albumin was globally more glycated in AD patients than in healthy controls (P<0.01). MS results in plasma were confirmed by a quantitative enzymatic assay (Lucica GA-L) for albumin early-glycation detection. In CSF there were no global glycation differences detected by MS, although a different pattern of glycated isoforms was observed. Oxidized+glycated and cysteinylated+glycated isoforms were increased in both plasma and CSF of AD patients in comparison with healthy controls (P<0.001). Furthermore, AD patients showed higher glycation in plasma than in CSF (P<0.01). Our data support the role of glycation and oxidative stress in AD.