Andy Coghlan in New Scientist:
Everyone knows that kids get their brains, or lack of them, from their parents. But it now seems that the reverse is also true. Stray stem cells from a growing fetus can colonise the brains of mothers during pregnancy, at least in mice.
If the finding is repeated in humans, the medical implications could be profound. Initial results suggest that the fetal cells are summoned to repair damage to the mother’s brain. If this is confirmed, it could open up new, safer avenues of treatment for brain damage caused by strokes and Alzheimer’s disease, for example.
This is a long way off, but there are good reasons for thinking that fetal stem cells could one day act as a bespoke brain repair kit. It is already well known that during pregnancy a small number of fetal stem cells stray across the placenta and into the mother’s bloodstream, a phenomenon called microchimerism. They can survive for decades in tissues such as skin, liver and spleen, where they have been shown to repair damage.