Traumatic brain injury causes intestinal damage, study finds

December 6, 2017, University of Maryland School of Medicine

University of Maryland School of Medicine (UMSOM) researchers have found a two-way link between traumatic brain injury (TBI) and intestinal changes. These interactions may contribute to increased infections in these patients, and may also worsen chronic brain damage.

This is the first study to find that TBI in mice can trigger delayed, long-term changes in the colon and that subsequent bacterial infections in the gastrointestinal system can increase posttraumatic inflammation and associated tissue loss. The findings were published recently in the journal Brain, Behavior, and Immunity.

"These results indicate strong two-way interactions between the brain and the gut that may help explain the increased incidence of systemic infections after and allow new treatment approaches," said the lead researcher, Alan Faden, MD, the David S. Brown Professor in Trauma in the Departments of Anesthesiology, Anatomy & Neurobiology, Psychiatry, Neurology, and Neurosurgery at UMSOM, and director of the UMSOM Shock, Trauma and Anesthesiology Research Center.

Researchers have known for years that TBI has significant effects on the gastrointestinal tract, but until now, scientists have not recognized that brain trauma can make the colon more permeable, potentially allowing allow harmful microbes to migrate from the intestine to other areas of the body, causing infection.. People are 12 times more likely to die from blood poisoning after TBI, which is often caused by bacteria, and 2.5 times more likely to die of a digestive system problem, compared with those without such .

In this study, the researchers examined mice that received an experimental TBI. They found that the intestinal wall of the colon became more permeable after trauma, changes that were sustained over the following month.

It is not clear how TBI causes these gut changes. A key factor in the process may be enteric glial cells (EGCs), a class of cells that exist in the gut. These cells are similar to brain astroglial cells, and both types of glial cells are activated after TBI. After TBI, such activation is associated with brain inflammation that contributes to delayed tissue damage in the brain. Researchers don't know whether activation of ECGs after TBI contributes to intestinal injury or is instead an attempt to compensate for the injury.

The researchers also focused on the two-way nature of the process: how gut dysfunction may worsen brain inflammation and tissue loss after TBI. They infected the mice with Citrobacter rodentium, a species of bacteria that is the rodent equivalent of E. coli, which infects humans. In mice with a TBI who were infected with this the bacteria, worsened. Furthermore, in the hippocampus, a key region for memory, the mice who had TBI and were then infected lost more neurons than animals without infection.

This suggests that TBI may trigger a vicious cycle, in which brain injury causes gut dysfunction, which then has the potential to worsen the original brain injury. "These results really underscore the importance of bi-directional gut-brain communication on the long-term effects of TBI," said Dr. Faden.

Explore further: Do spinal cord injuries cause subsequent brain damage?

Related Stories

Do spinal cord injuries cause subsequent brain damage?

November 14, 2014
Most research on spinal cord injuries has focused on effects due to spinal cord damage and scientists have neglected the effects on brain function. University of Maryland School of Medicine (UM SOM) researchers have found ...

Brain healing after injury given a natural boost

June 19, 2017
We may be able to kick-start healing after a traumatic brain injury by boosting levels of a protein made naturally within the brain, according to new research conducted at the University of Adelaide.

Researchers identify how inflammation spreads through the brain after injury

March 8, 2017
Researchers have identified a new mechanism by which inflammation can spread throughout the brain after injury. This mechanism may explain the widespread and long-lasting inflammation that occurs after traumatic brain injury, ...

What causes brain problems after traumatic brain injury? Studies have a surprising answer

January 15, 2015
A new paper by researchers at the University of Maryland School of Medicine (UM SOM) argues that there is a widespread misunderstanding about the true nature of traumatic brain injury and how it causes chronic degenerative ...

Head injury causes the immune system to attack the brain

October 20, 2014
Scientists have uncovered a surprising way to reduce the brain damage caused by head injuries - stopping the body's immune system from killing brain cells. The study, published in the open access journal Acta Neuropathologica ...

Air evacuation may do further harm in patients with brain injury, study says

November 30, 2015
Over the past 15 years, more than 330,000 U.S. soldiers have suffered a traumatic brain injury (TBI). It is one of the leading causes of death and disability connected to the country's recent conflicts in Afghanistan and ...

Recommended for you

Researchers unravel why people with HIV suffer from more neurologic diseases

August 20, 2018
Human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS), which the HIV virus can cause, continue to be one of the world's greatest health problems.

Fluidically linked blood-brain barrier and Organ Chips offer new method for studying effects of drugs on the brain

August 20, 2018
The human brain, with its 100 billion neurons that control every thought, word, and action, is the most complex and delicate organ in the body. Because it needs extra protection from toxins and other harmful substances, the ...

Female mice are immune to cognitive damage from space radiation

August 20, 2018
Humankind still dreams of breaking from the bounds of Earth's atmosphere and venturing to the moon, Mars and beyond. But once astronauts blast past the International Space Station, they become exposed to one of the many dangers ...

Antidepressant restores youthful flexibility to aging inhibitory neurons in mice

August 20, 2018
A new study provides fresh evidence that the decline in the capacity of brain cells to change, called "plasticity," rather than a decline in total cell number may underlie some of the sensory and cognitive declines associated ...

Children with brain tumors who undergo radiation less likely to recall recent events

August 20, 2018
Children with certain types of brain tumors who undergo radiation treatment are less likely to recall the specifics of events they experienced after radiation than to remember pre-treatment happenings, according to a Baylor ...

Rogue proteins may underlie some ALS and frontotemporal dementia cases, says study

August 20, 2018
ALS—amyotrophic lateral sclerosis—is a neurodegenerative disease that attacks motor neurons in the brain and spinal cord, slowly robbing its victims of their ability to walk, talk, breathe and swallow. In a cruel twist, ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.