Document Type
Article
Language
eng
Publication Date
11-1997
Publisher
Elsevier
Source Publication
Brain Research
Source ISSN
0006-8993
Original Item ID
DOI: 10.1016/S0006-8993(97)81684-8
Abstract
Brains from 41 aged canines (≥10 years of age) were examined immunohistochemically to characterize the laminar distribution and age-related progression of β-amyloid (Aβ) in frontal cortex. We classified the Aβ patterns into four distinct types. Type I was characterized by small, faint deposits of Aβ in deep cortical layers. Type II consisted of diffuse deposits of Aβ mainly in layers V and VI. Type III had both dense plaques in superficial layers, and diffuse deposits in deep layers. Finally, Type IV had solely dense plaques throughout all layers of cortex. We compared the Aβ distribution pattern between the Old canines (10–15 years, n=22) and the Very Old canines (>15 years, n=19). The Old group primarily had negative staining, or Type I and Type II patterns of amyloid deposition (73%). Conversely, the Very Old group had predominantly Types II, III and IV deposits (89.5%), a difference that was significant (Pβ deposition in canine frontal cortex is a progressive age-related process beginning with diffuse deposits in the deep cortical layers followed by the development of deposits in outer layers. In support of this hypothesis, the deeper layer diffuse plaques in the Very Old group of dogs also contain the largest proportion of β-amyloid with an isomerized aspartic acid residue at position 7, indicating that these deposits had been present for some time. We also observed fiber-like Aβ immunoreactivity within regions of diffuse Aβ deposits. These fibers appeared to be degenerating neurites, which were negative for hyperphosphorylated tau. Therefore, these fibers may represent a very early form of neuritic change that precede tau hyperphosphorylation or develop by an alternative pathway.
Recommended Citation
Satou, Takao; Cummings, Brian J.; Head, Elizabeth; Nielson, Kristy A.; Hahn, Fletcher F.; Milgram, Norton W.; Velazquez, Peter; Cribbs, David H.; Tenner, Andrea J.; and Cotman, Carl W., "The Progression of β-amyloid Deposition in the Frontal Cortex of the Aged Canine" (1997). Psychology Faculty Research and Publications. 118.
https://epublications.marquette.edu/psych_fac/118
Comments
Accepted version. Brain Research, Vol. 774, No. 1-2 (November 1997): 35-43. DOI. © 1997 Elsevier Science B.V. Used with permission.
Kristy Nielson was affiliated with the University of California - Irvine at time of publication.