Neurodegenerative changes in human aging brain. An autopsy study.

Neurodegenerative pathological changes are known as occurring in human brain, in some way paralleling aging. We characterized prospectively the occurrence of cortical senile plaques and neurofibrillary tangles in 55 adult human subjects, by post-mortem examination. We tried to determine if aging is associated with greater senile plaque and neurofibrillary tangles burden and what is the cortical distribution of lesions, regardless the mental status of the patient. The series comprised a large spectrum of ages, from 30 to 97-year-old. Immunohistochemistry for amyloid-beta (Abeta) and tau protein was the technique we used. ApoE genotyping was performed in 33 cases by polymerase chain reaction. In our series brain Abeta deposition as senile plaques occurred only after 65-year-old. These accumulations were strongly associated with the occurrence of neurofibrillary tangles. However, several very old patients were lacking both beta-amyloid and tau-positive lesions. As a result, even though Abeta and tau protein show a certain predilection for brain deposition in elder people, their relationship with aging still needs further investigation, mostly in human subjects.