Microglia cells promote buildup of protein plaques, while astrocytes help break them down

Microglial cells are the major factor driving plaque formation by fibrillar amyloid-beta (Abeta) deposition.

• The amount of fibrillar Abeta released by microglial cells and the contact area between amyloid and neurons influence neuronal damage.
• Hypertrophic astrocytic processes serve as a protective measure, separating fibrillar amyloid from neurons.
• Three stages of classical plaque development are identified: early, mature, and late.
• In the early stage, microglial cells primarily deposit fibrillar Abeta, leading to amyloid star formation.
• The mature stage reflects a balance of amyloid production, neuronal damage, and astrocyte growth.
• Late plaques show retraction of microglial cells, which increases neuronal damage and astrocytic activation, leading to plaque degradation.

Simplified