Lipid peroxidation status in cerebrospinal fluid samples from Alzheimer disease: Molecular and cell biology/oxidative stress

Background Oxidative stress has been postulated as one of the mechanisms implied in Alzheimer Disease (AD). Brain lipids are especially vulnerable against reactive species due to the high metabolic activity in the brain. Our previous studies reported the utility of lipid peroxidation biomarkers in plasma as potential AD diagnosis biomarkers. The aim of this work is to study the brain specificity for these biomarkers. Method Lipid peroxidation products (isoprostanes, isofurans, neuroprostanes, neurofurans) were determined in cerebrospinal fluid (CSF) and plasma samples from AD patients (n= 42) and non‐AD participants (n= 34). For this, an analytical method based on liquid chromatography coupled to mass spectrometry was used. Participants’ classification was carried out following the NIA‐AA criteria based on standard CSF biomarkers, structural neuroimaging and neuropsychological evaluation. Correlations between both biofluids were evaluated by means of Pearson Correlation. Result Most of the determined analytes did not show correlation between plasma and CSF levels. Only the compound 17( RS )‐10‐epi‐SC‐Δ 15 ‐11‐dihomo‐IsoF showed a slight correlation between both matrices. However, CSF lipid peroxidation levels showed correlation with CSF amyloid beta or tau levels. Conclusion CSF lipid peroxidation biomarkers levels could reflect amyloid pathology and cognitive impairment associated to AD. However, these levels are not directly correlated with the corresponding plasma concentrations, probably due to transport alterations through the blood brain barrier.