Repair mechanisms of the central nervous system: From axon sprouting to remyelination

The central nervous system (CNS), comprising the brain, spinal cord, and optic nerve, has limited regenerative capacity, posing significant challenges in treating neurological disorders. Recent advances in neuroscience and neurotherapeutics have introduced promising strategies to stimulate CNS repair, particularly in the context of neurodegenerative diseases such as multiple sclerosis. This review explores the complex interplay between inflammation, demyelination, and remyelination possibilities. Glial cells, including oligodendrocyte precursors, oligodendrocytes, astrocytes and microglia play dual roles in injury response, with reactive gliosis promoting repair but also potentially inhibiting recovery through glial scar formation. There is also an emphasis on axonal regeneration, axonal sprouting and stem cell therapies. We highlight the role of neuroplasticity in recovery post-injury and the limited regenerative potential of axons in the CNS due to inhibitory factors such as myelin-associated inhibitors. Moreover, neurotrophic factors support neuronal survival and axonal growth, while stem cell-based approaches offer promise for replacing lost neurons and glial cells. However, challenges such as stem cell survival, integration, and risk of tumor formation remain. Furthermore, we examine the role of neurogenesis in CNS repair and the remodeling of the extracellular matrix, which can facilitate regeneration. Through these diverse mechanisms, ongoing research aims to overcome the intrinsic and extrinsic barriers to CNS repair and advance therapeutic strategies for neurological diseases.