IDENTIFICATION OF SHORT-CHAIN OXIDIZED PHOSPHATIDYLCHOLINE IN HUMAN PLASMA

Oxidized phospholipids have been recognized as potentially important c ompounds that carry biological activities similar to the platelet-acti vating factor, but their presence in biological tissue has not been fi rmly established. We developed a novel technique for the quantitative analysis of phospholipids with oxidized acyl chains. The method involv es 1) lipid extraction, 2) chromatographic enrichment of phospholipids with short acyl chains, 3) derivatization with 9-(chloromethyl)anthra cene, 4) solid-phase extraction of the derivatives, and 5) reversed-ph ase HPLC with fluorescence detection. The technique nas capable of mea suring dicarboxylate-containing phosphatidylcholines (PCs) at the pico mole level. The method was suited to monitor the generation of oxidize d phospholipids from 1-palmitoyl-2-arachidonoyl-PC in the presence of Fe2+/ascorbate. The new procedure was used to isolate lipids from huma n plasma that were identified as anthracene derivatives of short-chain oxidized PC on the basis of chromatographic, enzymatic, and spectrosc opic evidence. The plasma concentration, determined with an internal s tandard (1-palmitoyl-2-suberoyl-PC), was 0.6 +/- 0.2 mu M (n = 11). Th e analytical method did not produce oxidation artifacts in significant amount. We concluded that human blood contains oxidatively fragmented PC in submicromolar concentration.-Schlame, M., R. Haupt, I. Wiswedel , W.J. Kox, and B. Rustow. Identification of short-chain oxidized phos phatidylcholine in human plasma.