Biomarkers of lipid peroxidation: analytical aspects

During these last years, oxidative stress has been implicated in various pathological situations. The difficulty is to choose a convenient marker to appreciate its importance in vivo because of analytical problems of specificity and sensitivity. The oxidized lipids, formed during lipid peroxidation, illustrate these problems. Among these markers are 'primary' products such as hydroperoxides, or 'secondary' products such as malondialdehyde ( MDA), 4-hydroxynormal ( 4-HNE) and isoprostanes. They are all measurable in biological fluids and analytical methods used are sometimes complex and require sample preparation involving extraction and purification steps. F2-isoprostanes are certainly the most specific markers of lipid peroxidation but also the most difficult to measure. Many assays have been recently developed. Some, such as gas or liquid chromatography coupled with mass spectrometry are the 'gold standard' methods, they allow to measure different F2-isoprostanes but require special apparatus. Others, like immunoassay methods measure one isoprostane, they are simpler to perform and accessible to a greater number of laboratories but still lack of specificity.