Researchers at the Memorial Sloan Kettering Cancer Center recently reported that it was possible to repair brain damage caused by radiation therapy for brain cancer by using lab-generated cells derived from human stem cells. The study was published in the journal Cell Stem Cell, and entitled “Human embryonic stem cell-derived oligodendrocyte progenitors remyelinate the brain and rescue behavioral deficits following radiation.”
Radiation is one of the therapies often used in treating brain cancer patients. However, it can induce significant and irreversible damage to the brain that can lead to deterioration of the quality of life for cancer survivors. After radiation therapy, the progenitor cells that would eventually evolve to generate the protective myelin coating surrounding neurons are lost or significantly reduced, and it is currently not possible to restore these cells. This protective myelin coating is generated by oligodendrocytes, which are vital for the support, protection, and repair of brain neurons.
A research team led by Dr. Viviane Tabar and Dr. Jinghua Piao showed that stem cells could be used as a tool to restore destroyed oligodendrocyte progenitor cells. Stem cells are undifferentiated cells capable of differentiating into different specialized cell types, like the skin, bone, muscle, etc.
The team developed a new strategy where they could transform human stem cells, in the presence of a cocktail of molecules including growth factors, into cells programmed to repair brain injuries — oligodendrocyte progenitor cells. This strategy was successfully accomplished with both human embryonic stem cells and induced pluripotent stem cells from the skin.
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The lab-generated oligodendrocyte progenitor cells where then implanted in rats that had been previously subjected to brain irradiation, and had therefore suffered de-myelination of neurons and presented cognitive deficits. Remarkably, rats treated with these specific human progenitor cells re-acquired their cognitive and motor coordination functions that were lost after exposure to radiation. In terms of safety, the team found that none of the rats developed any kind of inappropriate cell types or brain tumors.
“Being able to repair radiation damage could imply two important things: improving the quality of life of survivors and potentially expanding the therapeutic window of radiation,” said Dr. Tabar in a news release. “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.” This idea could be especially advantageous in the case of children, to whom physicians, by caution, apply lower doses of radiation during therapy.
