Vulnerability of white matter to ischemia varies during development

Stroke is the one of the leading causes of mortality and morbidity in developed countries. The central role of injury to white matter in the pathophysiology of stroke has been recognized over the recent years. Stroke can affect a wide range of the population (from the premature infant to the elderly) and therefore the mechanism of injury of central white matter may vary with age. The main aim of this review paper is to shed some light on the difference in maturation of injury to the axon-oligodendrocyte unit following an ischemic insult between different developmental stages. Both components of this unit exhibit varying degrees of susceptibility to ischemia throughout their development. Axons are particularly resistant to ischemia in the neonatal stage. However, they show a marked decreased in tolerance to ischemia during the period of myelination. Late oligodendrocyte progenitor cells (OPC) are the most sensitive type of oligodendrocyte, and their role in periventricular leukomalacia (PVL) is well known. On the other hand, early OPC are particularly resistant to ischemia. Studying the effect of ischemia on white matter in the brain during the different developmental stages will lead to a better understanding of the pathophysiology of white matter injury and hopefully, in the future, to the development of new therapeutic strategies of the various white matter diseases.