Developmental changes of apolipoprotein E immunoreactivity in Down syndrome brains
1Department of Mental Retardation and Birth Defect Research, National Center for Neurology and Psychiatry, Tokyo, Japan.
Brain Research. Developmental Brain Research
|July 14, 1995
Summary
Apolipoprotein-E (apo-E) producing astrocytes are elevated in the frontal cortex of Down syndrome brains, suggesting a role in early dementia. Apo-E plaques appear by age 25, preceding amyloid precursor protein (APP) plaques.
Area of Science:
- Neuroscience
- Genetics
- Pathology
Background:
- Down syndrome is associated with an increased risk of cognitive decline and dementia.
- Apolipoprotein-E (apo-E) plays a role in lipid transport and is implicated in neurodegenerative diseases.
- Understanding the temporal expression of apo-E in Down syndrome brains is crucial for elucidating pathological mechanisms.
Purpose of the Study:
- To investigate the temporal expression profile of apolipoprotein-E (apo-E) in the brains of individuals with Down syndrome compared to normal controls.
- To correlate apo-E expression patterns with the development of neuropathological hallmarks like senile plaques.
Main Methods:
- Immunohistochemical analysis was employed to detect apo-E immunoreactivity in brain tissue.
- Brain samples were obtained from Down syndrome patients and normal controls across a wide age range, from fetal development to adulthood.
- Quantification of apo-E immunoreactive astrocytes and senile plaques was performed in specific brain regions, including the frontal cortex and white matter.
Main Results:
- An increased number of apo-E immunoreactive astrocytes was observed in the frontal cortex of Down syndrome patients from 7 months to 24 years of age.
- Conversely, a decreased number of apo-E immunoreactive astrocytes was found in the white matter of Down syndrome patients from 28 gestational weeks to 5 years.
- Apo-E immunoreactive senile plaques were detected in Down syndrome brains starting at 25 years of age, with amyloid precursor protein (APP) immunoreactivity appearing in plaques later, at 32 years.
Conclusions:
- Elevated apo-E producing astrocytes in the frontal cortex during early development may contribute to presenile dementia in Down syndrome.
- The distinct temporal and regional expression patterns of apo-E suggest a complex role in Down syndrome neuropathology.
- The early appearance of apo-E in senile plaques highlights its potential involvement in the initial stages of plaque formation in Down syndrome.
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