title: Development of homogeneous assay for simultaneous measurement of apoE-deficient, apoE-containing, and total HDL-cholesterol.
abstract: BACKGROUND
  Pathophysiological role for high-density lipoprotein (HDL) subclasses remains to be elucidated. Homogeneous assay for simultaneous measurements of apoE-deficient HDL-cholesterol (HDL-C), apoE-containing HDL-C, and total HDL-C is desired, because apoE plays important roles in lipid metabolism.
  
  
  METHODS
  The proposed assay consists of a primary reaction to remove non-HDL-C, a secondary reaction to measure apoE-deficient HDL-C, and a tertiary reaction to measure apoE-containing HDL-C. The assay is completed within 10 min. For control study, 13% polyethylene glycol precipitation assay and phosphotungstate-dextran sulfate-magnesium precipitation assay were carried out.
  
  
  RESULTS
  Good correlations between the control assays and the proposed assay was obtained in serum samples from patients without liver disease (n=33): r=0.987, 0.957, and 0.991 for apoE-deficient, apoE-containing, and total HDL-C, respectively. ApoE-containing HDL-C by the proposed method in healthy individuals (n=12) and patients with hyper-HDL-cholesterolemia (n=5) were 0.11±0.03 and 0.26±0.05 mmol/l (4.1±1.3 and 10.1±2.0 mg/dl), respectively. ApoE-containing HDL-C increased rapidly at >2.59 mmol/l (100 mg/dl) of total HDL-C, suggesting a unique regulating mechanism of apoE-containing HDL-C.
  
  
  CONCLUSIONS
  The established homogeneous assay might be useful for clinical and epidemiological studies on apoE-deficient and apoE-containing HDL subclasses.
authors.affiliation: Faculty of Health Sciences, Hokkaido University, Sapporo, Japan; Department of Clinical Laboratory, Sapporo City General Hospital, Sapporo, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Reagent R & D Department, Denka Seiken Co., Ltd., Niigata, Japan.
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Department of Diabetes and Endocrinology, Sapporo City General Hospital, Sapporo, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Wada
authors.affiliation: Department of Infectious Diseases, Sapporo City General Hospital, Sapporo, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nagasaka
authors.affiliation: Department of Clinical Laboratory, Sapporo City General Hospital, Sapporo, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Fujikawa
authors.affiliation: Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Sakurai
authors.affiliation: Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.
authors.forename: Rojeet
authors.initials: R
authors.lastname: Shrestha
authors.affiliation: Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.
authors.forename: Shu-Ping
authors.initials: SP
authors.lastname: Hui
authors.affiliation: Faculty of Health Sciences, Hokkaido University, Sapporo, Japan. Electronic address: chibahit@med.hokudai.ac.jp.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Chiba
mesh_terms: D001057:Apolipoproteins E / Q000097:blood* / Q000172:deficiency*; D001774:Blood Chemical Analysis / Q000379:methods*; D008076:Cholesterol, HDL / Q000097:blood*; D064368:Healthy Volunteers; D006801:Humans
chemical_list: D001057:Apolipoproteins E; D008076:Cholesterol, HDL
keywords: Analytical systems; Enzymatic methods; Lipids