Published by the Students of Johns Hopkins since 1896
February 26, 2024

Dr. Q explains how the brain fights back

By BARBARA HOLT | September 12, 2013

When we think of cancer research, our first thought is usually of dangerous, but necessary, medical treatments like chemotherapy, radiation, and various invasive surgeries, whose destructive forces can kill healthy cells along with the damaged, leaving patients feeling weakened and sick.

Yet, perhaps, the human body is even more resilient than scientists ever realized. What if the human body has, in fact, been equipped to heal itself all along?

Alfredo Quiñones-Hinojosa, doctor and professor of neurosurgery at Johns Hopkins School of Medicine, and his laboratory team bring a new spark of hope to the fight against cancer with a discovery, which could potentially lead to both a better understanding of our brain’s “repair system,” its failings, and the possibility of an improved form of medical treatment.

The description of their ongoing study in the August edition of the journal Stems Cells details the discovery of the incredible radiation-resistance of neural stem cells in mice.

Employing a new high-precision localized-radiation instrument, uniquely developed at Hopkins by John Wong, professor and director of medical physics at the School of Medicine, the laboratory was able to simulate the radiation treatment received by human brain cancer patients on the rodent brain.

“The same technology and principles used to treat humans was used, but the difference was the tool must be developed for an unbelievable level of accuracy,” Quiñones-Hinojosa said. “The effects on the rodent brain could then be used to extrapolate the effects on the human brain.”

Amazingly, the neural stem cells were not only able to resist the spectrum of radiation to which they were exposed, but they also began to work to repair the damaged areas of the brain, generating healthy new cells to replace the injured ones and restore overall brain function.

According to Quiñones-Hinojosa, it is not the radiation which rouses the neural stem cells to action, but the brain injury itself that activates them.

Testing further the neural stem cells restorative abilities, the scientists used a substance known as lysolecithin to produce demyelinated (myelin being the protective sheath surrounding a neuron) brain lesions in the mice, simulating those found in humans suffering from Multiple Sclerosis.

Neural stem cells immediately began producing new brain cells which rushed to the affected area. Within a month these new cells had distributed themselves among the demyelinated lesion and begun producing new myelin to protect the nerve cells. “There is the potential that these same tools and abilities found in neural stem cells are similar to the properties and characteristics brain tumors use to defend themselves,” Quiñones-Hinojosa said.

If that is indeed the case, researchers may be able to study these properties to better understand what happens when the neural stem cells themselves cause brain tumors. For starters, this discovery might explain why radiation is so ineffective against glioblastoma, the most aggressive and deadly form of brain cancer.

It is not yet clear why the brain, having this ability to restore itself, does not heal itself in all brain injuries or neurological conditions. Preliminary research into this phenomenon suggests it may involve over-activity in certain parts of the brain. However, the results have been largely inconclusive.

Looking ahead to future research, Quiñones-Hinojosa and his laboratory have many exciting prospects to explore.

“We realize radiation is not the answer for everything,” Quiñones-Hinojosa said. “At the end of the day, this is just a man-made study and the rodent brain is different from a human brain.”

Future efforts will attempt to account for the various other “natural” factors which may be bypassed by a man-made lesion or other brain injury.

“In potential future studies we would like actual brain tumors to be implanted in the rodent brain and radiated,” Quiñones-Hinojosa said.

The brain’s response may hold even more surprises as to the innate restorative ability and resilience of the mammalian brain.

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