Figure 1.

Schematic representation of glial activation.

Notes: As a result of brain damage (eg, brain trauma, ischemia, Aβ accumulation, NFTs, etc) microglia and astrocytes acquire a so-called reactive phenotype losing their physiological functions. Morphofunctional changes, loss of three-dimensional network, and neurovascular unit alterations contribute to cause a homeostatic imbalance. Moreover, after activation, these cells produce a wide range of cytokines and proinflammatory mediators, leading to chronic inflammation. Even if the initial intent of these modifications is reparative, such long-lasting and uncontrolled activation causes further neurodegeneration.

Abbreviations: ROS, reactive oxygen species, NO, nitric oxide; Aβ, β-.amyloid; NFTs, neurofibrillary tangles; BBB, blood–brain barrier.