Stem Cell Therapy for Post-Concussion Syndrome
Post-concussion syndrome (PCS) is the persistence of concussion symptoms after the normal recovery timeframe. Most symptoms of concussion resolve within 1-2 weeks, and full recovery is expected at one month. However, with PCS, concussion-like symptoms occur in response to physical or cognitive activity, or they can occur at rest. Only 10% of people who suffer concussion will continue to have symptoms and develop PCS. Around 1.7 million people in the US sustain a traumatic brain injury (TBI) each year. The economic impact is estimated in the billions.
Mesenchymal stem cells (MSCs) are used to treat traumatic brain injury and PCS, with good reported results. Many clinical studies have proven stem cell therapy to be safe clinically. The primary mechanism of action involves the stem cells’ ability to differentiate into neural (nerve-brain cells). In addition, MSCs secrete paracrine soluble factors, which can stabilize the endothelium and prevent excessive permeability. Stem cells also suppress cells of the innate and adaptive immune system.
Animal Studies involving Stem Cell Therapy
In a large number of clinical studies, transplanted MSCs were cultured without growth factors. However, the use of cultured MSCs increased survival rate in some animal subjects. One study team found increased expression of astrocytic and neuronal markers, as well as improvement in motor function. In a study where stem cells were injected into the brain, survival rate was higher when compared to IV administration. Other research reports found that MSCs helped increase neuronal growth, endothelial regeneration, and increased insulin production.
Pre-clinical studies involving mice and rats have been promising. In one study, human stem cells, along with cyclosporine A, was given in subjects with traumatic brain injury. The study scientists found improvement of focal brain damages, as well as cryogenic lesions in these subjects. Incidentally, the timing of stem cell administration appears to be a factor also. When stem cells are given soon after brain injury, the subject had better results.
Other studies have been shown to assist with treatment of brain injury. Transplanted MSCs have been found to release pro-inflammatory cytokines following brain injury. They also were found to increase certain substances in the cerebrospinal fluid. Transplanted stem cells were found to improve neurological outcomes in rat subjects, with migration to the damaged brain portions documented by brain scan. These findings suggest functional improvement after traumatic brain injury, which involves early restoration of cerebral blood flow.
Studies involving Human Subjects
Post-concussion syndrome has been treated recently with stem cells in a human study. Around 90% of patients reported improvement of their conditions after stem cell therapy. In a recent study, 25 patients were given stem cells from bone marrow within 48-76 hours after injury. Functional and cognitive outcomes were evaluated clinically and using scans. The treatment group had structural preservation of critical regions of interest that correlated with inflammatory cytokines and functional outcomes.
Researchers have made progress to replenish lost myelin-producing cells of the nervous system and brain. In one study, scientists successfully cultured human stem cells to make cultures that contained oligodendrocytes. Myelin promotes normal neuronal function, and it inhibits the growth of new axons after brain or spine injury. Stem cells also repair trauma through promotion of neuron differentiation. When the cells migrate to the site of injury, they have been proven to regenerate myelin sheaths.
Cox CS. (2016). Treatment of severe adult traumatic brain injury using bone marrow mononuclear cells. DOI: 10.1002/stem.2538
Gennai S, Monsel A, Hao Q, et al. (2015). Cell-Based therapy for traumatic brain injury. Br J Anaesth, 115(2), 203-212.