Abstract
Accumulation of phosphatidylcholine hydroperoxide (PCOOH), a primary oxidation product of phosphatidylcholine, in blood plasma has been observed under vascular pathological conditions, such as atherosclerosis. PCOOH isomer analysis may lead to the elucidation of the mechanism of in vivo peroxidative reactions. In this study, we investigated the use of LC-MS/MS to develop a method for accurate quantification of PCOOH (1-palmitoyl-2-hydroperoxy-octadecadienoyl-sn-glycero-3-phosphocholine, 16:0/ HpODE PC), focusing specifically on isomers such as 16:0/9(13)-HpODE PC that might be predominantly present in human plasma. Collision-induced dissociation of sodiated PCOOH isomers ([M+Na]+, m/z 812) provided not only a known fragment ion (m/z 147), but also characteristic product ions (m/z 388 for 16:0/9-HpODE PC and m/z 541 for 16:0/13-HpODE PC). MRM (812/147) enabled determination of plasma PCOOH (16:0/HpODE PC), regardless of the position of the hydroperoxide group in the fatty acid. MRM (812/541 and 812/388) allowed specific measurement of 16:0/13-HpODE PC and 16:0/9-HpODE PC. By using this method, we could determine plasma PCOOH concentrations in healthy subjects and in patients with angiographically significant stenosis. In both plasma, the concentration of 16:0/HpODE PC was close to the sum of the concentrations of 16:0/13-HpODE PC and 16:0/9-HpODE PC. These findings suggest that radical- and/or enzymatic-oxidation, rather than singlet oxygen-oxidation, are recognized to cause peroxidation of fatty acid residues of lipoprotein membrane PC. The newly developed LC-MS/MS method appears to be a powerful tool for developing a better understanding of in vivo lipid peroxidation and its involvement in human diseases.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call