Researchers find long-term consequences for those suffering traumatic brain injury

Researchers from the University of South Florida and colleagues at the James A. Haley Veterans' Hospital studying the long-term consequences of traumatic brain injury (TBI) using rat models, have found that, overtime, TBI results in progressive brain deterioration characterized by elevated inflammation and suppressed cell regeneration. However, therapeutic intervention, even in the chronic stage of TBI, may still help prevent cell death.

Their study is published in the current issue of the journal .

"In the U.S., an estimated 1.7 million people suffer from traumatic ," said Dr. Cesar V. Borlongan, professor and vice chair of the department of Neurosurgery and at the University of South Florida (USF). "In addition, TBI is responsible for 52,000 early deaths, accounts for 30 percent of all injury-related deaths, and costs approximately $52 billion yearly to treat."

While TBI is generally considered an acute injury, secondary cell death caused by neuroinflammation and an impaired repair mechanism accompany the injury over time, said the authors. Long-term neurological deficits from TBI related to inflammation may cause more severe secondary injuries and predispose long-term survivors to age-related neurodegenerative diseases, such as Alzheimer's disease, and post-traumatic dementia.

Since the U.S. military has been involved in conflicts in Iraq and Afghanistan, the incidence of suffered by troops has increased dramatically, primarily from improvised explosive devices (IEDs), according to Martin Steele, Lieutenant General, U.S. Marine Corps (retired), USF associate vice president for veterans research, and executive director of Military Partnerships. In response, the U.S. Veterans Administration has increasingly focused on TBI research and treatment.

"Progressive injury to hippocampal, cortical and thalamic regions contributes to long-term cognitive damage post-TBI," said study co-author Dr. Paul R. Sanberg, USF senior vice president for research and innovation. "Both military and civilian patients have shown functional and cognitive deficits resulting from TBI."

Because TBI involves both acute and chronic stages, the researchers noted that animal model research on the chronic stages of TBI could provide insight into identifying therapeutic targets for treatment in the post-acute stage.

"Using animal models of TBI, our study investigated the prolonged pathological outcomes of TBI in different parts of the brain, such as the dorsal striatum, thalamus, corpus callosum white matter, hippocampus and cerebral peduncle," explained Borlongan, the study's lead author. "We found that a massive neuroinflammation after TBI causes a second wave of cell death that impairs cell proliferation and impedes the brain's regenerative capabilities."

Upon examining the rat brains eight weeks post-trauma, the researchers found "a significant up-regulation of activated microglia cells, not only in the area of direct trauma, but also in adjacent as well as distant areas." The location of inflammation correlated with the cell loss and impaired cell proliferation researchers observed.

Microglia cells act as the first and main form of immune defense in the central nervous system and make up 20 percent of the total glial cell population within the brain. They are distributed across large regions throughout the brain and spinal cord.

"Our study found that cell proliferation was significantly affected by a cascade of neuroinflammatory events in chronic TBI and we identified the susceptibility of newly formed within neurologic niches and suppression of neurological repair," wrote the authors.

The researchers concluded that, while the progressive deterioration of the TBI-affected over time suppressed efforts of repair, intervention, even in the chronic stage of TBI injury, could help further deterioration.

More information: Acosta SA, Tajiri N, Shinozuka K, Ishikawa H, Grimmig B, et al. (2013) Long-Term Upregulation of Inflammation and Suppression of Cell Proliferation in the Brain of Adult Rats Exposed to Traumatic Brain Injury Using the Controlled Cortical Impact Model. PLOS ONE 8(1): e53376. doi:10.1371/journal.pone.0053376

Related Stories

Prior brain injury linked to re-injury later in life

Jan 03, 2013

(HealthDay)—Older adults with a history of traumatic brain injury (TBI) with loss of consciousness (LOC) have a 2.5- to almost four-fold higher risk of subsequent re-injury later in life, according to research ...

What happens after traumatic brain injury occurs?

Nov 01, 2010

Results from a study published in the November issue of The Journal of Nuclear Medicine (JNM) show that powerful imaging techniques––positron emission tomography (PET) fused with magnetic resonance imaging (MRI)& ...

Recommended for you

New ALS associated gene identified using innovative strategy

13 hours ago

Using an innovative exome sequencing strategy, a team of international scientists led by John Landers, PhD, at the University of Massachusetts Medical School has shown that TUBA4A, the gene encoding the Tubulin Alpha 4A protein, ...

Can bariatric surgery lead to severe headache?

13 hours ago

Bariatric surgery may be a risk factor for a condition that causes severe headaches, according to a study published in the October 22, 2014, online issue of Neurology, the medical journal of the American Academy of Neurol ...

Bipolar disorder discovery at the nano level

14 hours ago

A nano-sized discovery by Northwestern Medicine scientists helps explain how bipolar disorder affects the brain and could one day lead to new drug therapies to treat the mental illness.

Brain simulation raises questions

17 hours ago

What does it mean to simulate the human brain? Why is it important to do so? And is it even possible to simulate the brain separately from the body it exists in? These questions are discussed in a new paper ...

Human skin cells reprogrammed directly into brain cells

17 hours ago

Scientists have described a way to convert human skin cells directly into a specific type of brain cell affected by Huntington's disease, an ultimately fatal neurodegenerative disorder. Unlike other techniques ...

User comments