Hormones As Biomarkers For Traumatic Brain Injury
Biomarkers that identify the presence or severity of brain injury have been a topic of increased interest lately. Whereas traditional scans or neurological tests often fail to accurately identify injury, a biomarker may be a relatively fast and easy way to determine those patients who are injured and need immediate treatment.
Hormones play an important role in traumatic brain injury. Research has shown that sex hormones can determine outcome after brain injury-with estradiol potentially having a neuroprotective effect, and testosterone having a potentially damaging effect on the brain.
After an injury, hormones continue to be problematic, with as many as 80% of those who suffer a brain injury also developing pituitary gland dysfunction and hypoendocrine disorders. The development of hormone problems after a brain injury may be related to direct or indirect damage to the hypothalamus and its connected pituitary gland. But, hormone problems also arise after any physical trauma, and may, in addition, be a result of the body's general reaction to stress.
Because hormones are so closely implicated with traumatic brain injury and outcome, a recent study from the University of Pittsburgh looked at hormone levels of 117 patients with severe traumatic brain injury in order to determine if certain hormones might act as a potential biomarker.
Some of their results contradicted past research. For instance, elevated levels of estradiol were associated with poor outcome (and was not necessarily neuroprotective as traditionally thought). Progesterone, which has recently been recognized as a potential therapy for acute brain injury, was confirmed to be low in both men and women.
Testosterone levels were high in both men and women, and were associated with worse outcome, as was expected. Changes in gonadal and thyroid hormones indicated that hormone changes at the acute stage of injury may be a response to the stress of physical trauma. In addition, older age was associated with a higher stress response and, therefore, a worsened outcome.
The results of this study show that hormone levels taken at the acute stage of traumatic brain injury may not only help to determine injury, but may also help to determine a specific hormonal treatment program that could improve overall outcome.
Wagner AK, McCullough EH, Niyonkuru C, et al. Acute serum hormone levels: Characterization and prognosis after severe traumatic brain injury. Journal of Neurotrauma. (June 2011).