Brain Repair: The Role of Endogenous and Transplanted Neural Stem Cells

Abstract:

Regenerative processes occurring under physiological and pathological (reparative) conditions are a fundamental part of life, and they vary greatly among different species, individuals and tissues. Physiological regeneration occurs naturally as a consequence of normal cell turnover, or as an inevitable outcome of any biological process requiring the restoration of homeostasis. Reparative regeneration occurs as a consequence of tissue damage. Although the central nervous system (CNS) has been considered for years as a 'perennial' tissue, it is now becoming clear that both physiological and reparative regeneration occur within the CNS to sustain tissue homeostasis and repair. Neural progenitor cells (NPCs) residing within the healthy CNS are emerging as crucial actors in both physiological as well as pathological conditions. Thus, a large number of experimental stem cell-based transplantation systems for CNS repair have recently been established, suggesting that transplanted NPCs might promote tissue repair not only via cell replacement but also via bystander (paracrine) mechanisms favourably influencing the diseased tissue milieu. This edition first published 2014