title: Diminished complement-activating capacity through the classical pathway in sera from type 2 diabetes mellitus.
abstract: Complement-activating capacity through the classical pathway in type 2 diabetes mellitus (T2DM) was examined in the context of free sialic acid as a potential modulator of complement activation. Complement-activating capacity was investigated in an incubation study of heat-aggregated IgG (HAG) and sera from 42 T2DM patients. The study demonstrated diminished in-vitro complement-activating capacity through the classical pathway in T2DM. Various doses of N-acetyl neuraminic acid (NANA) were incubated with normal serum and HAG. Complement activation product levels decreased in a NANA dose-dependent manner. Isoelectrofocusing analysis in a mixture of NANA and purified C3 indicated that C3 changed pI dose-dependently, resulting in the downregulation of complement activation. The serum levels of free sialic acid were determined by fluorometric assay in the 42 T2DM sera samples, and were significantly increased in patients with diminished complement activation. These data indicate that increased serum sialic acid may become a candidate for decreasing complement-activating capacity in T2DM.
authors.affiliation: Department of Nephrology, Hypertension and Endocrinology, Nihon University School of Medicine , Tokyo , Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Fujita
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Hemmi
authors.forename: Mamiko
authors.initials: M
authors.lastname: Kajiwara
authors.forename: Minako
authors.initials: M
authors.lastname: Yabuki
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Fuke
authors.forename: Atsushi
authors.initials: A
authors.lastname: Satomura
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Soma
mesh_terms: D000368:Aged; D003176:Complement C3 / Q000378:metabolism; D003171:Complement Pathway, Classical; D003924:Diabetes Mellitus, Type 2 / Q000276:immunology*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D056747:Immunomodulation; D008297:Male; D008875:Middle Aged; D019158:N-Acetylneuraminic Acid / Q000276:immunology / Q000378:metabolism*; D044967:Serum / Q000378:metabolism*
chemical_list: D003176:Complement C3; D007074:Immunoglobulin G; D019158:N-Acetylneuraminic Acid