title: Effects of serum amyloid A on the structure and antioxidant ability of high-density lipoprotein.
abstract: Serum amyloid A (SAA) levels increase during acute and chronic inflammation and are mainly associated with high-density lipoprotein (HDL). In the present study, we investigated the effect of SAA on the composition, surface charge, particle size and antioxidant ability of HDL using recombinant human SAA (rhSAA) and HDL samples from patients with inflammation. We confirmed that rhSAA bound to HDL3 and released apolipoprotein A-I (apoA-I) from HDL without an apparent change in particle size. Forty-one patients were stratified into three groups based on serum SAA concentrations: Low (SAA ≤ 8 μg/ml), Middle (8 < SAA ≤ 100 μg/ml) and High (SAA > 100 μg/ml). The ratios of apoA-I to total protein mass, relative cholesterol content and negative charge of HDL samples obtained from patients with high SAA levels were lower than that for samples from patients with low SAA levels. Various particle sizes of HDL were observed in three groups regardless of serum SAA levels. Antioxidant ability of rhSAA, evaluated as the effect on the formation of conjugated diene in low-density lipoprotein (LDL) induced by oxidation using copper sulfate, was higher than that of apoA-I. Consistent with this result, reconstituted SAA-containing HDL (SAA-HDL) indicated higher antioxidant ability compared with normal HDL. Furthermore, HDL samples obtained from High SAA group patients also showed the highest antioxidant ability among the three groups. Consequently, SAA affects the composition and surface charge of HDL by displacement of apoA-I and enhances its antioxidant ability.
authors.affiliation: Analytical Laboratory Chemistry, Field of Applied Laboratory Science, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Sato
authors.affiliation: Analytical Laboratory Chemistry, Field of Applied Laboratory Science, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan ryu-th@umin.ac.jp.
authors.forename: Ryunosuke
authors.initials: R
authors.lastname: Ohkawa
authors.affiliation: Analytical Laboratory Chemistry, Field of Applied Laboratory Science, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Yoshimoto
authors.affiliation: Analytical Laboratory Chemistry, Field of Applied Laboratory Science, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
authors.forename: Kouji
authors.initials: K
authors.lastname: Yano
authors.affiliation: Analytical Laboratory Chemistry, Field of Applied Laboratory Science, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Ichimura
authors.affiliation: Department of Clinical Laboratory, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors.forename: Madoka
authors.initials: M
authors.lastname: Nishimori
authors.affiliation: Department of Clinical Laboratory, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Okubo
authors.affiliation: Department of Clinical Laboratory, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yatomi
authors.affiliation: Analytical Laboratory Chemistry, Field of Applied Laboratory Science, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Tozuka
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D016632:Apolipoprotein A-I / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000378:metabolism; D008075:Lipoproteins, HDL / Q000097:blood* / Q000378:metabolism*; D008077:Lipoproteins, LDL / Q000097:blood / Q000378:metabolism; D010084:Oxidation-Reduction; D000685:Serum Amyloid A Protein / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D016632:Apolipoprotein A-I; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D000685:Serum Amyloid A Protein
keywords: antioxidant ability; high-density lipoprotein; inflammation; serum amyloid A