Strategies for the analysis of chlorinated lipids in biological systems

Myeloperoxidase-derived HOCl reacts with the vinyl ether bond of plasmalogens yielding alpha-chlorofatty aldehydes. These chlorinated aldehydes can be purified using thin-layer chromatography, which is essential for subsequent analysis of extracts from some tissues such as myocardium. The alpha-chlorofatty aldehyde 2-chlorohexadecanal (2-ClHDA) is quantified after conversion to its pentafluorobenzyl oxime derivative using gas chromatography-mass spectrometry and negative-ion chemical ionization detection. 2-ClHDA accumulates in activated human neutrophils and monocytes, as well as in atherosclerotic lesions and infarcted myocardium. Metabolites of 2-ClHDA have also been identified, including the oxidation product, 2-chlorohexadecanoic acid (2-ClHA), and the reduction product, 2-chlorohexadecanol. 2-ClHA can be quantified using LC-MS with selected reaction monitoring (SRM) detection. 2-ClHA can be omega-oxidized by hepatocytes and subsequently beta-oxidized from the omega-end, leading to the production of the dicarboxylic acid, 2-chloroadipic acid. This dicarboxylic acid is excreted in the urine and can also be quantified using LC-MS methods with SRM detection. Quantitative analyses of these novel chlorinated lipids are essential to identify the role of these lipids in leukocyte-mediated injury and disease. (c) 2012 Elsevier Inc. All rights reserved.