Traumatic brain injuries, like those caused by concussions, are common. But suffering even a mild brain injury boosts the likelihood of developing psychiatric or neurological disorders such as Alzheimer's disease. Exactly how and why that happens remains a mystery.
"Very little is known about how people with brain trauma -- like football players and soldiers -- develop neurological disorders later in life," said Fernando Gomez-Pinilla, PhD, a University of California, Los Angeles professor of neurosurgery and of integrative biology and physiology, in a recent news release.
Now, Gomez-Pinilla and his colleagues have discovered that a brain injury harms "master" genes that control other genes throughout the body. This triggers the alteration of hundreds of genes, which are linked to disorders like Alzheimer's disease, Parkinson's disease, PTSD, attention deficit hyperactivity disorder and depression. The study was recently published in EBioMedicine.
In the study, the researchers trained 20 rats to navigate through a maze. They then injected a fluid into the brain of half the rats to simulate a concussion-like brain injury. When all the rats were retested in the maze, the rats with a brain injury took about 25 percent longer than the controls to solve the maze -- indicating a change in basic cognitive function.
Next, the team investigated how the brain injuries altered the rats' genes. They analyzed RNA samples from the rats' white blood cells and hippocampi, the part of the brain that plays a central role in memory processes. In the injured rats, they found almost 300 genes had been altered in the hippocampus and over 1200 genes in the white blood cells.
More than 100 of these altered genes have counterparts in humans that are linked to neurological and psychiatric disorders. The researchers concluded that concussive brain injury reprograms key genes and this reprogramming could make neurological and psychiatric disorders more likely.
In addition, almost two dozen of the altered genes occurred in both the hippocampus and white blood cells. The researchers hope this genetic signature can be used to develop a gene-based blood test that determines whether a brain injury has occurred and whether future neurological disorders are likely.
They also hope their identification of master genes can give scientists new targets to develop better pharmaceuticals for brain disorders. However, more research is needed to fully understand the role of these master genes. Gomez-Pinilla said he now plans to study the phenomenon in people who have suffered a traumatic brain injury.
Previously: Jekyll & Hyde tale unfolding within the human brain may explain neurodegenerative disease, New research offers comprehensive picture of the lingering effects of sports injuries and Curious about concussions? A Stanford researcher reflects on current research, outstanding questions
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