Traumatic brain injury is a single name given to a broad variety of conditions. In every instance of traumatic brain injury, some external force causes damage to the brain. This may be mild and short-lived, such as a concussion, or severe and permanent, such as severe head trauma. The initial trauma or injury can cause a number of injuries to the skull and brain such as skull fracture, cerebral contusion (“brain bruise”), cerebral edema (“brain swelling”), or hemorrhage (“brain bleed”).
Traumatic brain injury can also cause several secondary injuries that may continue for hours or days. The secondary effects of traumatic brain injury include:
- Electrolyte imbalances
- Mitochondrial dysfunction
- Ischemia (lack of blood flow to parts of the brain)
- Brain cell destruction
These secondary traumatic brain injuries can cause long-term and even permanent neurological dysfunction.
Unfortunately, there are very few treatments for traumatic brain injury. Neurosurgeons can sometimes stop brain bleeding, stabilize skull fractures, and reduce brain swelling; however, there is little that can be done to stop the secondary effects of traumatic brain injury. Doctors have tried using steroids or hypothermia (cooling the patient) to decrease inflammation and stop further injury, but these interventions are not highly effective.
Ideally, one would give a treatment soon after a person has had a traumatic brain injury. This treatment would reduce or block the secondary effects of traumatic brain injury. Scientists are studying whether stem cell treatment can do that very thing.
Researchers recently showed that exosomes from bone marrow mesenchymal stem cells were able to reduce the secondary effects of traumatic brain injury. They humanely caused a traumatic brain injury in a group of mice. Fifteen minutes after the TBI, half the mice were given an injection of stem cells and the other half received a placebo (i.e. saltwater).
The mice that received the stem cell exosome treatment did substantially better than the mice who received a placebo. Stem cell exosome treatment substantially reduced the size of the damage to the brain compared to control. Moreover, mice that received stem cell exosome treatment did better on sensory, motor, reflex, and balance tests. In other words, stem cell exosome treatment helped mice with traumatic brain injury move better than those that did not receive stem cell exosome treatment.
The scientists went on to show that exosome treatment helped block the secondary effects of traumatic brain injury on the cellular and molecular level. In short, stem cell exosome treatment reduced inflammation in the brain from TBI.
Taken together, these results strongly suggest that treatment with exosomes from bone marrow mesenchymal stem cells soon after traumatic brain injury has the ability to protect the brain from damage. Of course, this treatment will need to be tested in humans who have had incidental TBI. Nevertheless, the basic science results are quite exciting since few neuroprotective agents, if any, can block the secondary effects of traumatic brain injury the way exosomes did in this scientific report.
Reference: Haoqi, N., et al. (2019). Exosomes Derived From Bone Mesenchymal Stem Cells Ameliorate Early Inflammatory Responses Following Traumatic Brain Injury. Frontiers in Neuroscience. 2019 Jan 24; 13:14.