A review of analytical methods for eicosanoids in brain tissue

Abstract

Eicosanoids are potent lipid mediators of inflammation and are known to play an important role in numerous pathophysiological processes. Furthermore, inflammation has been proven to be a mediator of diseases such as hypertension, atherosclerosis, Alzheimer's disease, cancer and rheumatoid arthritis. Hence, these lipid mediators have gained significant attention in recent years. This review focuses on chromatographic and mass spectrometric methods that have been used to analyze arachidonic acid and its metabolites in brain tissue. Recently published analytical methods such as LC-MS/MS and GC-MS/MS are discussed and compared in terms of limit of quantitation and sample preparation procedures, including solid phase extraction and derivatization. Analytical challenges are also highlighted.

Targeting brain and peripheral plasticity of the lipidome in acute kainic acid-induced epileptic seizures in mice via quantitative mass spectrometry

“…This study was carried out using tissue and blood sampling, handling and extraction procedures, and decapitation as sacrificing method that are equally carried out (see Materials and methods), both time-and procedure-wise, for epilepsy mice models and control mice in order to allow reliable comparative assessment of lipid levels in both groups. The procedure applied in our study did not allow and aim at quantifying and comparing endogenous lipid levels in KA-induced epileptic seizures and controls, as alterations of fatty acid metabolism by decapitation and/or anesthesia can occur [31][32][33]. It is well known that decapitation induces changes in the endogenous levels of bioactive lipids due to ischemia effects on fatty acid metabolism.…”

“…Determination of endogenous levels of bioactive lipids such as eicosanoids and endocannabinoids was shown to be very reliable when using microwave-irradiation, which leads to heat-inactivation of enzymes involved in synthesis and degradation of lipids. Thus, head-focused microwave irradiation was reported to allow measuring of brain lipids at their endogenous levels [24,[31][32][33]. Cravatt et coll.…”

The Brain Oxylipin Profile Is Resistant to Modulation by Dietary n‐6 and n‐3 Polyunsaturated Fatty Acids in Male and Female Rats

“…However, esterified oxylipin extraction requires a base hydrolysis step that potentially degrades a large number of oxylipins including PG and thromboxanes (Willenberg et al, ), and changes in the ratio of free versus esterified oxylipins in blood did not change after n‐3 PUFA supplementation (Schebb et al, ). Fifth, different solid phase extraction methods vary in their efficacy of oxylipin extraction; however, the method used in this study is the most efficient in general, although some of the ARA‐derived CYP oxylipins may not be extracted as well as by other procedures (Ostermann et al, ; Puppolo et al, ). This may explain why fewer of these metabolites were observed in the whole rat brain herein, compared to whole mouse brain (Ostermann et al, ).…”

Enantioseparation of hydroxyeicosatetraenoic acids by hydroxypropyl‐γ‐cyclodextrin‐modified micellar electrokinetic chromatography

“…A comprehensive analysis of natural and synthetic HETEs often requires separating both regioisomers and enantiomers. The regioisomer separation has frequently been performed using HPLC or GC on achiral stationary phases , whereas the enantiomer separation has been carried out using HPLC on chiral stationary phases . Using chiral‐phase HPLC with ultraviolet detection (HPLC–UV), Brash et al.…”

“…A comprehensive analysis of natural and synthetic HETEs often requires separating both regioisomers and enantiomers. The regioisomer separation has frequently been performed using HPLC or GC on achiral stationary phases [5,24,25], whereas the enantiomer separation has been carried out using HPLC on chiral stationary phases [19,[26][27][28][29][30][31]. Using chiral-phase HPLC with ultraviolet detection (HPLC-UV), Brash et al [19] showed that bis-allylic HETEs from rat liver microsomes were readily rearranged to conjugated diene-containing HETEs under mildly acidic conditions (1% acetic acid), e.g.…”