CSF sphingolipids and phospholipids characterization in dementia patients

Objectives: Cerebrospinal fluid (CSF) biomarkers have been recently described for the improvement of AD diagnosis, even though, to date, diagnosis remains mainly based on neuropsychological tests. The objective of the present effort is to transfer MALDI profiling technology to the study of lipid profile in CSF samples, to assess a MALDI specific CSF lipid profile and identify new biomarkers. Methods: Total lipids from CSF samples (AD n=10; idiopathic normal-pressure hydrocephalus (iNPH)=10; controls=10) were extracted according to Bligh and Dyer modified method and analyzed by MALDI. Profiles were analyzed by ClinProTools software. For sphingolipids and phospholipids characterization, lipid extracts were separated by HPTLC and directly analyzed by MALDI (Torretta E. et al, Electrophoresis 2014). Furthermore, for a direct MALDI CSF lipid analysis, crude CSFs diluted in distilled water (1:2) were analyzed by MALDI and peaks searched against NIST database. Results: Profiling preliminary results of lipid extracts from CSFs of 10 controls, 10 iNPH and 10 AD indicated a characteristic quantitative lipid CSF profile able to differentiate controls and iNPH vs AD. Sphingolipids and phospholipids semiquantitative pattern provides a characteristic pattern in AD vs iNPH and controls. Furthermore qualitative lipid characterization can be obtained by analyzing directly the crude CSF by MALDI in patients vs control samples for the identification of new lipid targets. Conclusions: MALDI profiling of CSF lipid extracts contributed to the detection of specific lipid profile and possible biomarkers for an early AD diagnosis. HPTLC-MALDI and direct lipid analysis offered a hint for the identification of new lipid markers.