title: Differences in reaction specificity toward lipoprotein X and abnormal LDL among 6 homogeneous assays for LDL-cholesterol.
abstract: BACKGROUND
  We investigated the reaction specificity toward cholesterol in lipoprotein X (Lp-X) and abnormal LDL among 6 homogeneous assays for low-density lipoprotein cholesterol (LDL-C) based on different measurement principles.
  
  
  METHODS
  The homogeneous LDL-C assays used were based on the liquid selective detergent, selective solubilization, elimination, enzyme-selective protection, calixarene complex, and phosphate complex inhibition methods. The fraction with a density of 1.006-1.063 kg/l was isolated from cholestatic sera, and the reactivity of cholesterol in the lipoprotein fractions by gel filtration for each homogeneous LDL-C assay was determined.
  
  
  RESULTS
  The liquid selective detergent and elimination methods showed increased cholesterol reactivity in the Lp-X fraction in a concentration-dependent manner, while the selective solubilization and phosphate complex inhibition methods were less reactive toward Lp-X cholesterol. Meanwhile, the homogeneous LDL-C assays showed decreased reactivity against cholesterol in abnormal LDL, with increased ratios of phospholipids and triglycerides against cholesterol.
  
  
  CONCLUSIONS
  The homogeneous LDL-C assays showed differential reactivity toward Lp-X and abnormal LDL. Our findings enable accurate interpretation of the LDL-C values in these homogeneous assays, and suggest that these methods should be improved to distinguish between normal LDL and abnormal LDL or Lp-X.
authors.affiliation: Department of Medical Technology, Kumamoto Health Science University, Kumamoto, Japan.
authors.forename: Kazumi
authors.initials: K
authors.lastname: Matsushima
authors.affiliation: Department of Medical Technology, Kumamoto Health Science University, Kumamoto, Japan. Electronic address: sugiuchi@kumamoto-hsu.ac.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sugiuchi
authors.affiliation: Department of Medical Technology, Kumamoto Health Science University, Kumamoto, Japan.
authors.forename: Kensaku
authors.initials: K
authors.lastname: Anraku
authors.affiliation: Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nishimura
authors.affiliation: Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Manabe
authors.affiliation: Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Ikeda
authors.affiliation: Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Ando
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kondo
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ishitsuka
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Irikura
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan; Center for Clinical Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Tetsumi
authors.initials: T
authors.lastname: Irie
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods*; D008078:Cholesterol, LDL / Q000097:blood*; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood*; D008073:Lipoprotein-X / Q000097:blood*; D013379:Substrate Specificity
chemical_list: D008078:Cholesterol, LDL; D008073:Lipoprotein-X
keywords: Abnormal LDL; Cholestasis; Homogeneous assays for LDL-cholesterol; Lecithin–cholesterol acyltransferase deficiency; Lipoprotein X; Reaction specificity