Adult nerve stem cells fall in the category of allusive creatures. A few scientists still question their existence and most suggest they exist in small numbers only in one or two locations in the adult brain. In any case, all agree they are not particularly good at the normal function of stem cells—making repairs to their surrounding tissue.
A research team at the University of California, San Francisco, recently published results providing two reasons why adult nerve stem cells are not very robust. First they don’t self-renew—make more copies of themselves—on a regular basis.
Second, the ones you were born with were preprogrammed before birth to become only a narrow subset of the many nerves we need for a fully functioning brain.
Working in mice, the team led by Arturo Alvarez-Buylla found several types of stem cells on the walls of cavities in the brain and each was pre-programmed to be “progenitors” for a specific subset of nerves. Like progenitors appeared to be lumped together by location and the team also tracked the time during embryo development when these destiny designations are made.
These results could make folks reconsider how they might use adult nerve stem cells for therapy. Alvarez-Buylla explained in a UCSF press release picked up by ScienceNewsline:
“It may be unwelcome news for those who thought of adult neural stem cells as having a wide potential for neural repair. Instead, it looks as if that potential is narrowed down very early during embryonic development. It’s almost as if the embryo is planning for the future.”
He went on to argue that the study points out the critical importance of understanding how stem cells develop and change in the embryo because that knowledge will guide how we use the various stem cells in therapy.
CIRM did not fund this study, but we do fund work in the Alvarez-Buylla lab that seeks to create nerve cells that can be implanted into people with diseases like epilepsy that result from an imbalance between different types of nerves.