Abstract
It has been reported that the existing direct method of high density lipoprotein (HDL) cholesterol measures particles enriched with apolipoprotein E (apoE). The aim of our study was to investigate a new analytical protocol to directly measure HDL cholesterol that eliminates apoE‐rich particles. The interactions of four lipoproteins (HDL3, HDL2, LDL, and VLDL + chylomicron) with surfactants, divalent cations, sugars, and lectins were investigated. By analyzing sera, HDL3, and HDL2, we examined the relationships among the measurements obtained by our protocol, a precipitation method using heparin‐MnCl2, and a commercially available kit for this direct method. A significant difference was found between the direct method and the heparin‐MnCl2 method, but not between our protocol and the heparin‐MnCl2 method. Multiple regression analysis showed that the difference between the direct method and the heparin MnCl2 method is dependent on sources of apoE‐rich HDL. In conclusion, our protocol enables a direct measurement of HDL cholesterol that eliminates apoE‐rich particles. J. Clin. Lab. Anal. 15:223–229, 2001. © 2001 Wiley‐Liss, Inc.
REFERENCES
- 1. Warnick GR, Wood PD. 1995. National cholesterol education program recommendations for measurement of high‐density lipoprotein cholesterol: executive summary. Clin Chem 41:14271–433. [PubMed] [Google Scholar]
- 2. Fielding PE, Miida T, Fielding CJ. 1991. Metabolism of low‐density lipoprotein free cholesterol by human plasma lecithin‐cholesterol acyltansferase. Biochemistry 30:8551–8557. [DOI] [PubMed] [Google Scholar]
- 3. Miida T, Kawano M, Fielding CJ, Fielding PE. 1992. Regulation of the concentration of preβ high‐density lipoprotein in normal plasma by cell membranes and lecithin‐cholesterol acyltransferase activity. Biochemistry 31:11121–11127. [DOI] [PubMed] [Google Scholar]
- 4. Salonen JT, Salonen R, Seppäen K, Rauramaa R, Tuomilehto J. 1991. HDL, HDL2, and HDL3 subfractions, and the risk of acute myocardial infarction, a prospective population study in eastern Finnish men. Circulation 84:129–139. [DOI] [PubMed] [Google Scholar]
- 5. Silva HV de, Ma‐Oliva J, Taylor JM, Mahley RW. 1994. Identification of apolipoprotein B‐100 low density lipoproteins, apolipoprotein B‐48 remnants, and apolipoprotein E‐rich high density lipoproteins in the mouse. J Lipid Res 35:1297–1310. [PubMed] [Google Scholar]
- 6. März W, Siekmeier R, Scharbagl H, Seiffert UB, Gross W. 1993. Fast lipoprotein chromatography: new method of analysis for plasma lipoproteins. Clin Chem 39:2276–2281. [PubMed] [Google Scholar]
- 7. Gibson JC, Rubinstein A, Brown WV. 1984. Precipitation of apo E‐containing lipoproteins by precipitation reagents for apolipoprotein B. Clin Chem 30:1784–1788. [PubMed] [Google Scholar]
- 8. Ng RH, Sparks KM, Statland BE. 1991. Direct measurement of high‐density lipoprotein cholesterol by the Reflotron assay with no manual precipitation step. Clin Chem 37:435–437. [PubMed] [Google Scholar]
- 9. Sugiuchi H, Uji Y, Okabe H, Irie T, Uekama K, Kayahara N, et al. 1995. Direct measurement of high‐density lipoprotein cholesterol in serum with polyethylene glycol‐modified enzymes and sulfated α‐cyclodextrin. Clin Chem 41:717–23. [PubMed] [Google Scholar]
- 10. Okamoto Y, Tanaka S, Nakano H. 1995. Direct measurement of HDL cholesterol preferable to precipitation method. Clin Chem 41:1784. [PubMed] [Google Scholar]
- 11. Hoel PG, editor. 1971. Introduction to mathematical statistics. 4th ed.New York: John Wiley & Sons. [Google Scholar]
- 12. Beheshti I, Wessels LM, Eckfeldt JH. 1994. EDTA‐plasma vs serum differences in cholesterol, high‐density lipoprotein cholesterol, and triglyceride as measured by several methods. Clin Chem 40:2088–2092. [PubMed] [Google Scholar]
- 13. Schectman G, Sasse E. 1993. Variability of lipid measurements: relevance for the clinician. Clin Chem 39:1495–1503. [PubMed] [Google Scholar]
- 14. Harris N, Galpchian V, Rifai N. 1996. Three routine methods for measuring high‐density lipoprotein cholesterol compared with the reference method. Clin Chem 42:738–743. [PubMed] [Google Scholar]
- 15. Enzi GB, Baroni BA, Baiocchi MR, Fellin R. 1985. Cholesterol determination in HDL, HDL2 and HDL3 fractions after polyanion precipitation: a comparison between chemical extractive and totally enzymatic procedures. Clin Chim Acta 146:81–86. [DOI] [PubMed] [Google Scholar]
- 16. Whitaker CF, Srinivasan SR, Berenson GS. 1986. Simplified methods for measuring cholesterol concentrations of high‐density lipoprotein subclasses in serum compared. Clin Chem 32:1274–1278. [PubMed] [Google Scholar]
- 17. Leino A, Viikari J, Koskinen P, Irjala K. 1987. Problems with PEG‐based precipitation methods in the determination of HDL2‐ and HDL3‐cholesterol. Scand J Clin Lab Invest 47:705–708. [DOI] [PubMed] [Google Scholar]
- 18. Sjoblom L, Eklund A. 1989. Determination of HDL2 cholesterol by precipitation with dextran sulfate and magnesium chloride: establishing optimal conditions for rat plasma. Lipids 24:532–534. [DOI] [PubMed] [Google Scholar]
- 19. Wilson PWF. 1995. Relation of high‐density lipoprotein subfractions and apolipoprotein E isoforms to coronary disease. Clin Chem 41:165–169. [PubMed] [Google Scholar]
- 20. Lane JT, Subbaiah PV, Otto ME, Bagdade JD. 1991. Lipoprotein composition and HDL particle size distribution in women with non‐insulin‐dependent diabetes mellitus and the effects of probucol treatment. J Lab Clin Med 18:120–128. [PubMed] [Google Scholar]