Axonal and neuronal degeneration in myelin diseases.

Myelin is a multilamellar cell membrane around axons and is essential for fast saltatory conduction and maintenance of axonal integrity and survival. Congenital and acquired abnormalities of myelin lead to neurological disorders involving degeneration and loss of axons and neurons, which are implicated in permanent neurological deficits and progressive neurological decline. As in other neurological disorders, neural degeneration and loss in myelin diseases are associated with multiple factors including aberrant inflammatory responses, oxidative stresses, and impaired axonal metabolism involving cationic sequestration and energy production. Metabolic regulation depends on mitochondrial function, and impaired mitochondrial dynamics cause degeneration and loss of axons and neurons. Future studies on the regulatory mechanisms of axonal and neuronal degeneration in myelin diseases, which include further development of animal models and better screening approaches for possible interventions, contribute to deeper understanding of axonal interactions with glia and myelin ensheathment and potentially lead to novel therapeutic strategies to protect the function and survival of axons and neurons in myelin diseases.