Oxidized Low-density Lipoprotein (OxLDL)

Overview:

For the in vitro quantitative measurement of oxidized low density lipoproteins (oxidized LDL) in human serum or plasma.

Measurement of oxidized LDL (oxLDL) has been incorporated into clinical practice in the diagnosis and treatment of lipid disorders (such as diabetes mellitus), atherosclerosis, and various liver and renal diseases, especially as it pertains to the evaluation of oxidative stress. Oxidized LDL-particles are considered to be an important driving factor in the pathophysiology of atherosclerosis and oxLDL measurement has been used to test the efficacy of CVD drugs (eg, statins) to reduce oxidative stress.9

Lipemic or hemolytic samples may give erroneous results and should not be used for analysis.

The oxidative conversion of low density lipoproteins (LDL) to oxidized low density lipoproteins (oxidized LDL) is now considered to be a key event in the biological process that initiates and accelerates the development of the early atherosclerotic lesion, the fatty streak.1-5

Experimental studies have shown that native LDL becomes atherogenic when it is converted to oxidized LDL, and that oxidized LDL is more atherogenic than native LDL.1-5 Oxidized LDL is found in monocyte-derived macrophages in atherosclerotic lesions, but not in normal arteries.6 The uptake of LDL into macrophages does not occur by way of the classic Brown/Goldstein LDL receptor.7 Numerous studies1-5,8 have established that LDL, the major carrier of blood cholesterol, must first be converted to oxidized LDL so that it can be recognized by "scavenger" or "oxidized LDL receptors" on monocyte-derived macrophages. The binding of oxidized LDL to macrophages is a necessary step by which oxidized LDL induces cholesterol accumulation in macrophages, thus transforming the macrophages into lipid-laden foam cells.8

1. Steinberg D. Low density lipoprotein oxidation and its pathobiological significance. J Biol Chem. 1997 Aug 22; 272(34):20963-20966. PubMed 9261091

2. Berliner JA, Navab M, Fogelman AM, et al. Atherosclerosis: basic mechanisms. Oxidation, inflammation, and genetics. Circulation. 1995 May 1; 91(9):2488-2496. PubMed 7729036

3. Steinberg D. Lewis A. Conner Memorial Lecture. Oxidative modification of LDL and atherogenesis. Circulation. 1997 Feb 18;95(4):1062-1071. PubMed 9054771

4. Heinecke JW. Oxidants and antioxidants in the pathogenesis of atherosclerosis: implications for the oxidized low density lipoprotein hypothesis. Atherosclerosis. 1998 Nov;141(1):1-15. PubMed 9863534

5. Witztum JL, Hörkkö S. The role of oxidized LDL in atherogenesis: immunological response and anti-phospholipid antibodies. Ann N Y Acad Sci. 1997 Apr 15;811:88-96; discussion 96-99. PubMed 9186588

6. Ylä-Herttuala S. Is oxidized low-density lipoprotein present in vivo? Curr Opin Lipidol. 1998 Aug;9(4):337-344. PubMed 9739490

7. Brown MS, Goldstein JL. Lipoprotein metabolism in the macrophage: implications for cholesterol deposition in atherosclerosis. Annu Rev Biochem. 1983;52:223-261. PubMed 6311077

8. Chisolm GM 3rd, Hazen SL, Fox PL, Cathcart MK. The oxidation of lipoproteins by monocytes-macrophages. Biochemical and biological mechanisms. J Biol Chem. 1999 Sep 10;274(37):25959-25962. PubMed 10473535

9. Pfützner A A, Efstrathios K, Löbig M, Armbruster FP, Hanefeld M, Forst T. Differences in the results and interpretation of oxidized LDL Cholesterol by two ELISA assays--an evaluation with samples from the PIOstat Study. Clin Lab. 2009;55(7-8):275-281. PubMed 19894406