Transplanted embryonic neurons can help rebuild circuits and restore function in the damaged brains of adult mice, reports a Nature paper published online this week. The finding is a boost for the field of neural transplantation, which seeks to repair brain injury and disease through the introduction of ‘replacement’ cells.
The brain has a very limited capacity to repair itself, so neural transplants are being developed as a possible treatment for conditions such as Parkinson’s disease and stroke. Although promising results have been obtained, it is unclear how similar these possible replacement cells are to the native cells which have been lost. To answer this question, Magdalena Gotz, Mark Hubener and colleagues used sophisticated imaging methods to follow the fate of embryonic neurons transplanted into the damaged visual cortex of mice.
The transplanted cells quickly began to extend processes, and by four weeks, looked very similar to the classic neuronal cells normally seen in the upper layers of the visual cortex. Moreover, the transplanted cells formed connections with host cells, were able to receive electrical signals from other parts of the brain and, notably, began to respond to visual stimuli. In essence, the transplanted cells looked like and acted like the missing cortical cells.
The results are also of interest because ‘repair’ occurred in an area of the adult brain that does not normally incorporate new neurons. This finding suggests that there may be molecular guidance cues that either persist in the adult brain or that are re-activated after injury.