Immunoreactive circulating oxidized HDL concentrations do not increase in patients undergoing carotid endarterectomy: a comparative study for oxidized HDL and oxidized LDL concentrations in plasma.

摘要

To the Editor, Circulating oxidized LDL is considered as a clinical marker and the overall data are consistent in stating that oxidized LDL concentrations are greater in patients with coronary artery diseases . However, although the mean concentrations of oxidized LDL significantly differ between patients and controls, the measurement itself distinguished only the part of the population tested, suggesting that the concentration of oxidized LDL may not be sufficiently robust to be used alone in diagnosis of individual patients. On the other hand, HDL and apolipoprotein (apo) AI, the major protein constituent of HDL, are highly susceptible to oxidation . Recent findings also indicate that myeloperoxidase, one of the enzymes that produces reactive oxygen species, oxidizes HDL preferentially in the circulation and the artery wall and thereby impairs the function for the reverse cholesterol transport , These observations suggest that oxidation of HDL is an early marker for atherosclerosis; however, the possibility has not fully been explored. We previously developed, for the first time, an enzyme-linked immunosorbent assay (EL1SA) with an antibody against an oxidized form of apoAI that detected HDL oxidized with Cu2~+, 2,2'-azobis (2-amidinopropane) dihy-drochloride. Moreover, we have shown in the paper that the antibody reacts with HOCl-modified HDL . By using the ELISA, we found that the association of serum oxidized HDL concentrations with the polymorphism in the gene encoding p22~(phox) of NADPH oxidase was stronger than that with oxidized LDL, implying the occurrence of HDL oxidation with increased oxidative stress in humans .