Adult stem cells have the ability to trace damaged tissue in the brain and repair it accordingly, says a US led study on mice.
This finding is of great interest because the same type of cells are also present in the human brain, and this knowledge can be put to therapeutic use in future, to treat brain tissues damaged by disorders such as traumatic injury.
Dr. Chay Kuo, a University of California-San Francisco postdoctoral fellow in the laboratory of senior investigator Yuh-Nung Jan, led the study.
'The results were very surprising,' said Kuo. 'They show that neural stem cells in mice have the ability to sense damage in their environment that leads to their subsequent proliferation to help restore local tissue integrity.'
In this study, mice, genetically engineered to have holes in a region of their brain, recovered due to the work of stem cells in the area.
The next step is to determine how these stem cells sense damage and then begin to work on the injured tissue. "If we can figure out how this happens, and determine that it occurs in human neural stem cells," says Chay T. Kuo, a researcher in Jan's lab, "we may be able to increase the effect and harness it for therapeutic use."
This study was conducted to throw light upon the molecular programs that control neural stem cells in the postnatal mouse and how the neural stem cells respond to tissue damage.
Kuo and his colleagues genetically engineered neural stem cells and ependymal cells in the SVZ of newborn mice in such a way that they lacked two key proteins, named Numb and Numblike.
A postnatal mouse brains autopsy conducted 7 and 14 days after the genetic modification revealed that absence of proteins Numb and Numblike led to severe brain ventricle enlargement.
To the astonishment of the researchers, the damage to the left ventricular wall was substantially repaired when these sick mice were examined six weeks later. This was suspected to be due to the limitation of the technique-some neural stem cells escaped gene deletion, thus allowing the Numb protein they synthesized to remain intact and some neural stem cells had continued to function.
As a response to the damage sensed in the region, these cells had, mediated and rebuilt the ventricular wall lining and succeeded in establishing a modified neural stem cell environment.
The scientists have still not deciphered the precise mechanism by which the stem cells carried out the response.
"The holes that had formed in the brain ventricular wall had largely been repaired. These adolescent mice looked quite good. The finding shows that the brain has the ability to repair itself and that it is more plastic than previously appreciated," said Dr Jan.