Astrocytic scars aid axon regrowth

It is widely believed that the astrocytic scars that develop following central nervous system (CNS) injury are a major obstacle to subsequent axonal regrowth. But here Michael Sofroniew and colleagues demonstrate that limiting the formation of the scar actually attenuates axon re-growth. Sustained delivery of axon-specific growth factors not typically present in spinal cord lesions allowed for robust re-growth, but only if the astrocytic scar was present. These results question the prevailing dogma and suggest that astrocyte scarring promotes — rather than prevents — CNS axon regeneration post-injury.