MedStar National Rehabilitation Hospital
Faculty provides care for thousands suffering from mild to traumatic brain injuries. The concussion clinic at Medstar NRH focuses primarily on this form of brain injury and is regarded as one of the best in the country according to U.S. News & World Report. 75 percent of all traumatic brain injuries that occur are concussions. Traumatic brain injuries contribute to a third of all deaths in the United States with over 1.5 million brain injuries occurring each year. During their stay, patients are also educated on precautions they can take to prevent a future incidence.
Axotomy
A traumatic brain injury is defined as a blunt non-missile penetrating or missile injury to the head. It has been shown that the extent of the damage incurred after a head trauma correlates more directly with the amount of deformation incurred by the brain than the amount of stress per area applied to the head. There are two modes of axotomy that can occur as a result of a TBI. Primary axotomy occurs immediately and is characterized as complete mechanical transaction of axons. More often, secondary axotomy occurs, evolving over time and ultimately leading to disconnection. While this type of injury is often irreversible, the axons do occasionally recover. Researchers are currently working towards utilizing this potential for recovery to develop therapies for patients suffering from traumatic brain injuries. These therapies rely on the scientific understanding of the axotomy response. Two mechanisms that aid in the reinnervation process are acute inflammation and the activation of molecules in the extracellular matrix surrounding the synapse. Immediate acute inflammation leads to the removal of the severed axons by activating the local glia. The inflammation response also recruits growth factors that aid in the repopulation of postsynaptic sites. The negative effects of this inflammation may be difficult to detect immediately post injury. Inflammation of the head is often slow to onset after injury, and can lead to a fatal rise in cerebral pressure. A recently discovered and understood cytokine is currently being used to try to treat the axotomy before the rise in pressure occurs. This cytokine, called osteopontin, may be able to aid in axon regeneration by exposing its integrin receptor binding sites. Osteopontin secretion may be able to regulate synaptogenesis and target the necessary neuroglia required for the repair of the axons. A study done by Julie L. Chan proves the functionality of osteopontin in initiating the immune response necessary for synaptic repair and reorganization after injury (axotomy). Though the study effectively proved the functionality of osteopontin in diminishing the intense inflammatory response following a traumatic brain injury, it did not provide evidence of the long-term effects of implanting this as a treatment option. Altering the inflammatory response may unintentional halt the beneficial aspects of inflammation and have devastating effects on the brain’s ability to heal itself.