title: Beta-amyloid accumulation in aged canine brain: a model of early plaque formation in Alzheimer's disease.
abstract: We characterized eight aged beagles (maintained from birth in a laboratory colony) and one black Labrador using Bielschowsky's, thioflavine S, and Congo red staining, and antibodies to the beta-amyloid peptide, dystrophic neurites, and other plaque components. All plaques within these canine brains were of the diffuse subtype and were neither thioflavine S- nor Congo red-positive. The majority of plaques in the entorhinal cortex contained numerous neurons within them while plaques in the dentate gyrus did not. beta-Amyloid immunoreactivity was also present within select neurons and neuronal processes and was detected as a diffuse linear zone corresponding to the terminal fields of the perforant path. There was no significant correlation between extent of beta-amyloid accumulation and neuron number in entorhinal cortex. Neither tau-1, PHF-1, nor SMI-31-immunostaining revealed dystrophic fibers, confirming the classification of these plaques as diffuse. Canine plaques did not appear to contain bFGF- or HS-positive immunostaining. This may explain why neuritic involvement was not detected within these canine plaques. It is possible that the beta-amyloid within the canine brain has a unique primary structure or may not be in an assembly state that adversely affects neurons.
authors.affiliation: Department of Psychobiology, University of California, Irvine 92717-4550.
authors.forename: B J
authors.initials: BJ
authors.lastname: Cummings
authors.forename: J H
authors.initials: JH
authors.lastname: Su
authors.forename: C W
authors.initials: CW
authors.lastname: Cotman
authors.forename: R
authors.initials: R
authors.lastname: White
authors.forename: M J
authors.initials: MJ
authors.lastname: Russell
mesh_terms: D000293:Adolescent; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D000544:Alzheimer Disease / Q000378:metabolism / Q000473:pathology*; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000818:Animals; D015415:Biomarkers; D001923:Brain Chemistry / Q000502:physiology*; D002531:Cerebellum / Q000473:pathology; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009474:Neurons / Q000502:physiology
chemical_list: D016229:Amyloid beta-Peptides; D015415:Biomarkers