title: Accumulation and absorption of serum amyloid A and apolipoprotein E fragments in the course of AA amyloidosis: a study in a mouse model.
abstract: Reactive AA amyloidosis develops secondary to chronic inflammatory disorders. Serum amyloid A protein (SAA) and its degradation products, named AAs, are the main components of amyloid deposits, while apolipoprotein E (apoE) fragments are the minor components. To further understand the molecular mechanism of AA amyloidosis, we examined SAA/AAs moieties and apoE in the spleen and plasma throughout the amyloid-generating and amyloid-absorbing phases in a mouse model. SAA and four AA species (8.5kDa, 7.8kDa, 7.0kDa, and 6.2kDa) were detected in the spleen. SAA and the 8.5 kDa and 7.8 kDa AAs were prominent in the acute phase, whereas the 7.0kDa AA, the second smallest AA corresponding to the most common form in the human disease, was prominent in the chronic phase. These results indicate that the higher molecular weight species first constituted the fibril, followed by the 7.0kDa species, which were finally absorbed. ApoE was a component of the amyloid deposits at a degradation size from the beginning and was absorbed without being converted to another size. Degradation products, either from SAA or apoE, did not appear in the plasma during the course of the disease. A more detailed understanding of the moieties of amyloid-related peptides may help in the development of a method that can indicate the disease activity of AA amyloidosis.
authors.affiliation: Department of Clinical Laboratory Medicine, Jichi Medical University, Japan.
authors.forename: Jyunji
authors.initials: J
authors.lastname: Sato
authors.affiliation: Department of Clinical Laboratory Medicine, Jichi Medical University, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Kotani
authors.affiliation: Department of Clinical Laboratory Medicine, Jichi Medical University, Japan yamadanji@jichi.ac.jp.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Yamada
mesh_terms: D000686:Amyloidosis / Q000503:physiopathology*; D000818:Animals; D001057:Apolipoproteins E / Q000378:metabolism*; D001774:Blood Chemical Analysis; D004195:Disease Models, Animal; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D000685:Serum Amyloid A Protein / Q000378:metabolism*; D013154:Spleen / Q000378:metabolism* / Q000473:pathology
chemical_list: D001057:Apolipoproteins E; D000685:Serum Amyloid A Protein
keywords: amyloidosis; apolipoprotein E; fragment; mouse; serum amyloid A