Oligodendrocyte progenitors: adult stem cells of the central nervous system?

Oligodendrocyte progenitors (OPs) are a major proliferating cell population within the adult CNS. In response to myelin loss or increasing demand, OPs have the capacity to differentiate into mature, myelinating oligodendrocytes. The name 'oligodendrocyte progenitor' suggests restriction to the oligodendrocyte cell lineage. However, with growing evidence of the lineage plasticity of OPs both in vitro and in vivo, we discuss whether they have potential beyond that expected of dedicated progenitor cells, and hence may justify categorization as adult stem cells.