title: Identification and cholesterol quantification of low density lipoprotein subclasses in young adults by VAP-II methodology.
abstract: Low density lipoprotein (LDL) particles are heterogeneous in size, density, and chemical composition; small, dense LDL may be more atherogenic than large, buoyant LDL. We have developed a rapid microscale method called LDL VAP-II (Vertical Auto Profile-II) for quantification of cholesterol in LDL subclasses. The method is based upon a short (1 h) single vertical spin density-gradient ultracentrifugation and on-line VAP-II analyzer. LDL VAP-II is rapid and reproducible. Using this method five LDL subclasses, designated as LDL-1 (most buoyant) through LDL-5 (most dense), have been identified in a population consisting of 195 medical students (ages, 22-29 years). The Rf (relative position of the major LDL peak in the density gradient; the higher the Rf value, the lower the peak density) was significantly positively correlated with cholesterol levels of high density lipoprotein (HDL) (r = 0.594), HDL3 (0.350) and HDL2 (0.625), and significantly negatively correlated with triglycerides (TG) (-0.355) and cholesterol levels of very low density lipoprotein (VLDL) (-0.386) and intermediate density lipoprotein (IDL) (-0.432). These results are consistent with those obtained by other investigators. The Rf value was significantly correlated with peak particle diameter as determined by non-denaturing gradient gel electrophoresis (r = 0.859). In a forward stepwise multivariate analysis comparing Rf with sex, VLDL, LDL, Lp[a], IDL, HDL3, HDL2, and triglyceride, only HDL2 remained in the model.
authors.affiliation: Department of Medicine, University of Alabama at Birmingham 35294, USA.
authors.forename: K R
authors.initials: KR
authors.lastname: Kulkarni
authors.forename: D W
authors.initials: DW
authors.lastname: Garber
authors.forename: M K
authors.initials: MK
authors.lastname: Jones
authors.forename: J P
authors.initials: JP
authors.lastname: Segrest
mesh_terms: D000328:Adult; D001322:Autoanalysis / Q000379:methods*; D002499:Centrifugation, Density Gradient / Q000379:methods*; D002784:Cholesterol / Q000097:blood*; D005260:Female; D006801:Humans; D008077:Lipoproteins, LDL / Q000097:blood*; D008297:Male; D009862:Online Systems; D010316:Particle Size; D012016:Reference Values; D015203:Reproducibility of Results; D013997:Time Factors; D014461:Ultracentrifugation
chemical_list: D008077:Lipoproteins, LDL; D002784:Cholesterol