Spinal cord regeneration — the origins of progenitor cells for functional rebuilding

The spinal cord is one of the most important structures for all vertebrate animals as it connects almost all parts of the body to the brain. Injury to the mammalian spinal cord has devastating consequences, resulting in paralysis with little to no hope of recovery. In contrast, other vertebrate animals have been known for centuries to be capable of functionally regenerating large lesions in the spinal cord. Here, we will review the current knowledge of spinal cord regeneration and recent work in different proregenerative animals that has begun to shed light on the cellular and molecular mechanisms these animals use to direct cells to rebuild a complex, functional spinal cord.