HNE-derived 2-pentylpyrroles are generated during oxidation of LDL, are more prevalent in blood plasma from patients with renal disease or atherosclerosis, and are present in atherosclerotic plaques

Free radical oxidation of human plasma low-density lipoprotein (LDL) produc es 2-pentylpyrrole epitopes that are generated by reaction of 4-hydroxy-2-n onenal (HNE), a product of lipid oxidation, with protein lysyl residues. Th e HNE-derived 2-pentylpyrrole ("HNE-pyrrole") epitopes were detected with a n enzyme-linked immunosorbent assay (ELISA) using antibodies (ON-KLH) raise d against protein-bound 2-pentylpyrrole obtained by the reaction of 2-oxono nanal (ON) with keyhole limpet hemocyanin (KLH). HNE-pyrrole epitopes in hu man plasma are not associated primarily with LDL protein, apolipoprotein (a po) B, since only 15% of the total HNE-pyrrole immunoreactivity is removed by immunoprecipitation of apo B. The levels of ON-KLH immunoreactivity dete cted in human plasma were found to be significantly elevated in renal failu re and atherosclerosis patients when compared to those in healthy volunteer s. HNE-pyrrole immunoreactivity was also detected in atherosclerotic plaque s. The highest levels were associated with extracellular connective tissue. Levels of ON-KLH immunoreactivity in human plasma far exceed levels of fre e HNE, presumably because of the rapid clearance of free relative to protei n-bound HNE. Therefore, HNE-pyrrole epitopes provide a more indelible marke r of oxidative injury than levels of free HNE.