Age-related progression of tau pathology in brains of baboons

Recently, cytoskeletal changes associated with abnormally phosphorylated ta u protein were demonstrated in neurons and glial cells of two aged baboons (Papio). The present study examines the effects of age on the development o f tau pathology in baboons. Brains of 50 baboons ranging in age from 1 to 3 0 years were categorized into four age groups: Group I: 1-10 years [n = 9], group II: 11-20 years In = 13], group III: 21-25 years [n = 17]. group IV: 26-30 years [n = 11]). Whole hemisphere sections (100 mum) were examined u sing phosphorylation-dependent anti-tan antibodies. Cytoskeletal changes we re completely absent in animals of group I. In group II four animals (31%)) exhibited cytoskeletal changes which were rated as mild or moderate. In gr oup III abnormal tau was found in 12 brains (71%) ranging in severity from mild to severe. Finally, in group IV 10 out of 11 animals (91%) exhibited s ome degree of tau pathology which was rated as severe in 3 animals (36%). A statistically significant relationship was found between advancing age and progression of tau pathology in baboons. In conclusion, the present findin gs underline the value of the baboon as a potential nonhuman primate model for age-related tau pathology afflicting the human brain. (C) 2000 Elsevier Science Inc. All rights reserved.