Abstract
Anamniotes and rodents maintain neural multipotent cells in the ependymal zone (EZ) around the central canal of the spinal cord. Our previous RNA profiling showed that immature developmental genes are still expressed even in the young human EZ. These ependymal cells maintain an embryonic-like spinal cord organization with the expression of typical spinal cord developmental/stem cell transcription factors such as Arx, Msx1, Pax6 or Sox2, 4,6,11 and cilia transcription factor FoxJ1. We and others found that these cells are multipotent and can generate neurons and glial cells in vitro. The maintenance of these cells in the adult or aged human spinal cord is still debated. We addressed this pending issue by collecting fresh spinal cords from 10 ageing humans (from 53 to 83 y.). Using immunolabelling techniques, we found a persistent lifelong expression of spinal cord developmental factors (Arx, Pax6, Msx1, Sox2 and FoxJ1) in the human EZ. A dorsal-ventral regionalization and a central lumen are also observed in most cases at all ages. The persistence of these embryonic-like cells in the aged human spinal cord potentially represents an interesting endogenous cellular source to alleviate various spinal cord lesions.