Tissue regeneration and repair in multiple tissue regeneration and repair in multiple sclerosis: The role of neural stem cells

The brain repair system Regeneration is a fundamental part of life. While physiological (spontaneous) regeneration naturally occurs upon cell attrition, injury-reactive (reparative) regeneration occurs as a consequence of tissue damage and greatly differs among different animals and tissues. After the first observation of reparative regeneration in a limb – via blastema formation in the crayfish – made in 1712 by René-Antoine Ferchault de Réaumur, the scientific community had to await Francisco Tello’s work, in the early twentieth century, to have preliminary evidence that also the central nervous system (CNS) has the ability to regenerate after an injury. The potential value of this observation was first recognized by Ramón y Cajal who described as “curious and significant” the experiment carried out by Tello: “When a piece of the distal stump of a sectioned nerve is introduced in a cerebral wound of a rabbit a regenerative capacity appears in the apathetic of the white substance. This demonstrates that the impotence of the central to restore the peripheral stump is neither fatal nor irremediable”. The seminal work of Tello has been recently rejuvenated by detailed in vitro and in vivo mechanistic evidence supporting the existence of an innate self-maintenance program, “the brain repair system,” sustaining brain homeostasis and repair upon injury.