Principles of gliopathology

Neuroglia contribute to the pathophysiology of all neurological diseases. Conceptually, such contributions can be primary, when pathological forms of neuroglial cells drive neuropathology, or secondary, when neuroglia respond to pathological lesions of varying aetiology. In contrast to neurones, neuroglial cells are designed to mount multiple lines of defence in response to pathology, collectively known as reactive gliosis. Reactive gliosis is generally protective and allostatic, aimed at the preservation of nervous tissue function and integrity. Dystrophic changes in neuroglia contribute to neuropathology through the loss of homeostatic and defensive functions. Astrocytopathies cover another group of pathological changes manifested by the emergence of aberrant glial forms that drive the neuropathology. Finally, neuroglial cells can undergo degeneration and death, which further weakens nervous system defences and exacerbates the progression and outcome of neurological disorders.