Until very recently it was thought that
the mature mammalian brain could not generate new neurons.Until very recently it was thought that
the mature mammalian brain could not generate new neurons.
Now, it has been shown that the cells lining the ventricles of the brain can act as stem cells to create a pool of rapidly dividing progenitor cells, which provide a source of neuronal and glial precursor cells.
The neural stem cells can be stimulated to divide in vitro by epidermal growth factor (EGF) or fibroblast growth factor-2 (FGF-2), the former favoring development of neurons and the later development of glial cells.
The cells were discovered when a retroviral vector (which incorporates only into dividing cells) was injected into the lateral ventricle and found to label some cells of the ventrical lining.
Possibly, the stem cells may be used to replace damaged cells in the event of brain injury.
If the in vitro cells, created through growth factor treatment, are transplanted into the intact brain they have been shown to integrate and differentiate into a range of neuronal and glial cells.
This raises the exciting possibility of developing therapies for neurodegenerative diseases.
A sample of ependymal cells from the lining of the ventricles could be removed, cultured in vitro in appropriate growth factors to induce cell division and differentiation.
The cells could then be injected into the donor brain to replace dead or damaged cells.