This Article Full Text Full Text (PDF) Data Supplement All Versions of this Article: 29/1/33    most recent ATVBAHA.108.164723v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kato, R. Articles by Itabe, H. Search for Related Content PubMed PubMed Citation Articles by Kato, R. Articles by Itabe, H. Pubmed/NCBI databases Substance via MeSH

(Arteriosclerosis, Thrombosis, and Vascular Biology. 2009;29:33.)
© 2009 American Heart Association, Inc.

Integrative Physiology/Experimental Medicine

Transient Increase in Plasma Oxidized LDL During the Progression of Atherosclerosis in Apolipoprotein E Knockout Mice

Rina Kato; Chihiro Mori; Keiko Kitazato; Satoru Arata; Takashi Obama; Masahiro Mori; Katsuhiko Takahashi; Toshihiro Aiuchi; Tatsuya Takano; Hiroyuki Itabe

From the Department of Biological Chemistry (R.K., C.M., K.K., T.O., K.T., T.A., H.I.), Center of Biotechnology (S.A.), Showa University School of Pharmaceutical Sciences, Japan; the Department of Molecular Pathology, Faculty of Pharmaceutical Sciences (M.M., T.T., H.I.), Teikyo University, Japan; and the Department of Neuronal Surgery (K.K.), Institute of Health Biosciences, and University of Tokushima Graduate School, Physiological Chemistry Research Laboratory (K.T.), Hoshi University, Japan.

Correspondence to Hiroyuki Itabe, PhD, Department of Biological Chemistry, Showa University School of Pharmaceutical Sciences, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan. E-mail h-itabe{at}pharm.showa-u.ac.jp

Background— Plasma level of oxidized low-density lipoprotein (OxLDL) is a risk marker for cardiovascular diseases. The behavior of plasma OxLDL before disease progression has not been studied previously.

Methods and Results— In this study, we developed a sensitive ELISA procedure for detecting mouse circulating OxLDL using a monoclonal antibody that recognizes oxidized phosphatidylcholine and a rabbit antimouse apolipoprotein B-48 polyclonal antibody. Apolipoprotein E knockout mice were fed on a chow diet for 40 weeks. Oil red O–positive lesions developed gradually by 20 weeks, and the percentage area covered by the lesions increased dramatically after 28 weeks; it covers 33.4% of the surface area by 40 weeks. The OxLDL level, measured after LDL fraction was isolated from each mouse, at 10 weeks was 0.015 ng/µg LDL. It increased 3-fold at 20 weeks of age and then decreased to the basal level by 40 weeks of age, suggesting that OxLDL appears before the development of atherosclerotic lesions. The occurrence of lipid peroxidation products, acrolein and oxidized phosphatidylcholines, in aortic tissue were revealed by immunohistochemical staining as early as 10 weeks.

Conclusion— These results suggest that OxLDL might be involved in the early stages of progression of atherosclerotic lesions.

We successfully measured murine circulating OxLDL using sandwich ELISA. ApoE knockout mice showed a significant rise in the plasma OxLDL level at 20 weeks of age, whereas the atherosclerotic lesions were still small. This suggests an increase in the oxidative stress and the appearance of OxLDL before the progression of atherosclerotic lesions.

Key Words: oxidized low-density lipoprotein • atherosclerosis • apoE-knockout mouse • ELISA • oxidized phosphatidylcholine