Kazumi Matsushima1, Hiroyuki Sugiuchi2, Kensaku Anraku1, Hitoshi Nishimura3, Masahiro Manabe3, Katsuyoshi Ikeda3, Yukio Ando3, Yuki Kondo4, Yoichi Ishitsuka4, Mitsuru Irikura4, Tetsumi Irie5. 1. Department of Medical Technology, Kumamoto Health Science University, Kumamoto, Japan. 2. Department of Medical Technology, Kumamoto Health Science University, Kumamoto, Japan. Electronic address: sugiuchi@kumamoto-hsu.ac.jp. 3. Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan. 4. Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan. 5. Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan; Center for Clinical Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan.
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. CONCLUSION: 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.
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. CONCLUSION: 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: Agnieszka Ćwiklińska; Agnieszka Mickiewicz; Robert Kowalski; Barbara Kortas-Stempak; Agnieszka Kuchta; Krzysztof Mucha; Michał Makowiecki; Anna Gliwińska; Krzysztof Lewandowski; Leszek Pączek; Marcin Fijałkowski; Marcin Gruchała; Maciej Jankowski Journal: J Med Biochem Date: 2020-09-02 Impact factor: 3.402