Neurofibrillary tangles and senile plaques in aged bears.
In aged human beings and in individuals with age-associated degenerative disorders, particularly Alzheimer's disease (AD), neurons develop cytoskeletal abnormalities, including neurofibrillary tangles (NFT) and senile plaques (SP). Senile plaques occur in several nonhuman species; however, NFT, with ultrastructural or immunocytochemical similarities to those occurring in humans, have not been identified in other mammals. In this study of five aged bears (Ursus, 20-30 years of age), we identified cytoskeletal abnormalities similar to those occurring in humans. An aged Asiatic brown bear had NFT, composed of straight 10-16-nm filaments, that were immunoreactive with antibodies directed against: phosphorylated epitopes of neurofilaments (NF); tau; A68 (a protein enriched in AD); and an antigen associated with paired helical filaments (PHF). An aged polar bear had numerous SP; neurites of these plaques were immunoreactive with antibodies against phosphorylated epitopes of NF, but NFT were not identified. These results indicate that nonprimate species develop age-related cytoskeletal abnormalities similar to those occurring in humans. Investigations of the comparative pathology of aged mammals may be useful in elucidating the pathogeneses of these abnormalities.
Cork
L C
LC
Division of Comparative Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2182.
Powers
R E
RE
Selkoe
D J
DJ
Davies
P
P
Geyer
J J
JJ
Price
D L
DL
D000544:Alzheimer Disease / Q000473:pathology; D000818:Animals; D001921:Brain / Q000254:growth & development* / Q000473:pathology / Q000648:ultrastructure; D002335:Carnivora / Q000254:growth & development*; D006801:Humans; D008854:Microscopy, Electron; D009454:Neurofibrils / Q000648:ultrastructure*; D009928:Organ Specificity; D013045:Species Specificity; D001503:Ursidae / Q000254:growth & development*