title: Age-dependent changes in brain, CSF, and plasma amyloid (beta) protein in the Tg2576 transgenic mouse model of Alzheimer's disease.
abstract: The accumulation of amyloid beta protein (Abeta) in the Tg2576 mouse model of Alzheimer's disease (AD) was evaluated by ELISA, immunoblotting, and immunocytochemistry. Changes in Abeta begin at 6-7 months as SDS-insoluble forms of Abeta42 and Abeta40 that require formic acid for solubilization appear. From 6 to 10 months, these insoluble forms increase exponentially. As insoluble Abeta appears, SDS-soluble Abeta decreases slightly, suggesting that it may be converting to an insoluble form. Our data indicate that it is full-length unmodified Abeta that accumulates initially in Tg2576 brain. SDS-resistant Abeta oligomers and most Abeta species that are N-terminally truncated or modified develop only in older Tg2576 mice, in which they are present at levels far lower than in human AD brain. Between 6 and 10 months, when SDS-insoluble Abeta42 and Abeta40 are easily detected in every animal, histopathology is minimal because only isolated Abeta cores can be identified. By 12 months, diffuse plaques are evident. From 12 to 23 months, diffuse plaques, neuritic plaques with amyloid cores, and biochemically extracted Abeta42 and Abeta40 increase to levels like those observed in AD brains. Coincident with the marked deposition of Abeta in brain, there is a decrease in CSF Abeta and a substantial, highly significant decrease in plasma Abeta. If a similar decline occurs in human plasma, it is possible that measurement of plasma Abeta may be useful as a premorbid biomarker for AD.
authors.affiliation: Mayo Clinic Jacksonville, Jacksonville, Florida 32224, USA.
authors.forename: T
authors.initials: T
authors.lastname: Kawarabayashi
authors.forename: L H
authors.initials: LH
authors.lastname: Younkin
authors.forename: T C
authors.initials: TC
authors.lastname: Saido
authors.forename: M
authors.initials: M
authors.lastname: Shoji
authors.forename: K H
authors.initials: KH
authors.lastname: Ashe
authors.forename: S G
authors.initials: SG
authors.lastname: Younkin
mesh_terms: D000375:Aging / Q000378:metabolism*; D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000097:blood / Q000134:cerebrospinal fluid / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000032:analysis / Q000097:blood / Q000134:cerebrospinal fluid; D000818:Animals; D015415:Biomarkers / Q000032:analysis / Q000097:blood / Q000134:cerebrospinal fluid; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D001923:Brain Chemistry; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005561:Formates / Q000737:chemistry; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009928:Organ Specificity; D058225:Plaque, Amyloid / Q000378:metabolism / Q000473:pathology; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D015415:Biomarkers; D005561:Formates; C030544:formic acid; D012967:Sodium Dodecyl Sulfate