Oxidative Lipidomics Coming of Age: Advances in Analysis of Oxidized Phospholipids in Physiology and Pathology

Abstract

Significance: Oxidized phospholipids are now well recognized as markers of biological oxidative stress and bioactive molecules with both pro-inflammatory and anti-inflammatory effects. While analytical methods continue to be developed for studies of generic lipid oxidation, mass spectrometry (MS) has underpinned the advances in knowledge of specific oxidized phospholipids by allowing their identification and characterization, and it is responsible for the expansion of oxidative lipidomics. Recent Advances: Studies of oxidized phospholipids in biological samples, from both animal models and clinical samples, have been facilitated by the recent improvements in MS, especially targeted routines that depend on the fragmentation pattern of the parent molecular ion and improved resolution and mass accuracy.

Structure Annotation and Quantification of Wheat Seed Oxidized Lipids by High-Resolution LC-MS/MS

“…Previous studies on the systematic quantification and identification of oxidized lipids were conducted mainly using either semitargeted MS/MS (Vu et al, 2012;Spickett and Pitt, 2015) or untargeted high-resolution Figure 3. Quantitative analysis of oxidized lipids in long-term stored wheat seeds under ambient and cold conditions.…”

“…Targeted liquid chromatography-mass spectrometry (LC-MS) analysis of oxidized lipids using authentic standards is not very common (Hui et al, 2010;Ravandi et al, 2014). Often, oxidized lipids are detected using tandem mass spectrometry (MS/MS), where the collision-induced products of precursor ions (PRs) are scanned for fragments or neutral losses (NLs) that correspond to oxidized acyl residues expected in oxidized lipids (Spickett and Pitt, 2015), and in some cases, higher resolution MS/MS spectra are provided to support the identification (Buseman et al, 2006;Vu et al, 2012).High-resolution mass spectrometry (MS) allows for the quantification and detection of analytes based on their accurate mass. It has been applied in the analysis of known or expected nonoxidized lipids in biological samples in a growing number of studies for more than a decade now either by direct infusion (shotgun lipidomics; Ejsing et al, 2009;Schwudke et al, 2011) or in combination with liquid chromatography Hummel et al, 2011 …”

“…Targeted liquid chromatography-mass spectrometry (LC-MS) analysis of oxidized lipids using authentic standards is not very common (Hui et al, 2010;Ravandi et al, 2014). Often, oxidized lipids are detected using tandem mass spectrometry (MS/MS), where the collision-induced products of precursor ions (PRs) are scanned for fragments or neutral losses (NLs) that correspond to oxidized acyl residues expected in oxidized lipids (Spickett and Pitt, 2015), and in some cases, higher resolution MS/MS spectra are provided to support the identification (Buseman et al, 2006;Vu et al, 2012).…”

“…But the availability of and knowledge regarding MS/MS spectra of oxidized lipids are quite scarce and restricted to single lipid species like TAGs (Zeb, 2012) and PLs (Spickett and Pitt, 2015) or to particular acyl residues like oxidized C18 and C16 FA esters (Vu et al, 2012). All in all, there has been a lack of suitable strategies to generate and annotate untargeted high-resolution MS/MS spectra of an untargeted quantitative highresolution LC-MS experiment in order to quantify and identify as many oxidized lipids as possible from a set of samples.…”

The Changing Face of HDL and the Best Way to Measure It

“…A similar fluorometric biochemical assay based on the oxidation of dihydrorhodamine 123 by HDL was developed by Kelesidis, et al (79 ), featuring methodology that allowed for differentiation of HDL oxidative potential in different persons and a high-throughput implementation. Other techniques are available to quantify oxidized phospholipids, including immunoassays, separation techniques, and mass spectrometry assays (80 ). Methodology for detecting and quantifying oxidized phospholipids is advancing rapidly, and will be continually refined as mass spectroscopy techniques improve.…”