Radiation is a powerful treatment for brain cancer, but this potentially life-saving treatment comes with a heavy cost, which is permanent damage to the brain.
Preclinical work at Memorial Sloan Kettering Cancer Center has shown that human stem cells can be used to make cells that repair radiation-induced damage in the brain.
When rats were treated with radiation and then given cocktails to the human stem cells, they regained the cognitive and motor functions that were lost after brain irradiation.
In the brain, stem cells called OPCs or oligodendrocyte progenitor cells mature into oligodendrocytes that produce the protective myelin coating that surrounds axons in the central nervous system. During radiation treatment, OPCs die off and are depleted. Because OPCs help shield and repair the myelin sheath throughout the life of the organism, depletion of them threatens the integrity of the myelin sheath, which threatens the proper transmission of neural impulses throughout the brain.
A research project led by neurosurgeon Viviane Tabar and her research associate Jinghua Piao wanted to use stem cells to replace these lost OPCs. They used human embryonic stem cells and human induced pluripotent stem cells to make cultured OPCs.
In the next phase of the experiment, Taba, Piao and their coworkers treated rats whose brains had been irradiated with their cultured OPCs. After injection of the stem cell-derived OPCs, brain repair was evident and the rats regained their cognitive and motor function that they had previously lost as a consequence of radiation exposure.
The treatment appeared quite safe since none of the animals developed any tumors or aberrant growths.
The ability to repair radiation damage could mean that the quality of cancer survivors could be greatly improved and it could also expand the therapeutic window of radiation, according to Tabor.
“This will have to be proven further, but if we can repair the brain effectively, we could be bolder with our radiation dosing, within limits,” said Tabor.
Such a treatment scheme could also be very important in children, for whom physicians must use lower doses of radiation to limit brain damage.