Different inflammation patterns in brain immune cells and brain changes in Alzheimer's model mice

Microglia were activated around Aβ plaques in TgAPP/PS1 mice as early as 6 months, indicating potential early biomarkers for Alzheimer's disease.

• Aβ plaques in Alzheimer's disease may precede cognitive deficits by decades, but early diagnostic biomarkers are currently unavailable.
• Microglia and astrocytes showed activation and clustering around Aβ plaques, with microglial activation increasing significantly between 6 and 12 months.
• Phagocytosis of Aβ was observed in microglia but not in astrocytes at 6 months of age.
• Activated microglia upregulated proinflammatory and anti-inflammatory factors, while reactive astrocytes did not express these cytokines.
• A decrease in neural stem cells and immature neurons was noted in 3-month-old TgAPP/PS1 mice prior to Aβ deposits.
• Diffusion tensor imaging indicated reduced fractional anisotropy in the dentate gyrus and altered connectivity in brain networks at 6 months.

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