Pentosidine determination in CSF: a potential biomarker of Alzheimer's disease?

The histopathological hallmarks in Alzheimer's disease (AD) include neuronal cell death, formation of amyloid plaques and neurofibrillary tangles. Glycoxidation plays a crucial role in AD pathogenesis, as pentosidine and Nε- carboxymethyl-lysine (CML), were detected in AD hallmarks, and in vivo cerebrospinal fluid (CSF). However, the definitive role of AGEs in the neuropathology of AD is inconclusive. The aim of this preliminary study was to assess the level of pentosidine in CSF of patients affected by neurological disorders, including probable AD, in order to assess the feasibility of AGEs detection in CSF and to explore pentosidine as a potential biomarker in AD.

Twenty-five patients diagnosed with AD (NINCDS ADRDA criteria) and different neurological disorders were enrolled. Diabetic patients were excluded. Pentosidine, CML, amyloid β1-42 were assessed by high performance liquid chromatography (HPLC) by Odetti modified method,and by sandwich ELISA respectively.

Our data showed the presence of pentosidine in all CSF samples, a significant increase in CSF pentosidine levels with age (p<0.05) and a significant decreased concentration of pentosidine in four AD subjects (p<0.01), after normalization to CSF protein concentration.

The study showed that AGEs concentration in CSF might benefit from age correction, at least for pentosidine, originally addressing a potential systemic age-dependent AGEs accumulation. The significant decrease of CSF pentosidine in AD, even in 4 patients, might conceive that different AGEs inform specific types of neurodegeneration, depending on oxidative stress levels, blood - brain barrier permeability, brain localization and systemic risk factors.