Scientists are looking to biomarkers, or biological indicators, in the blood to help them differentiate between brain injuries of different severities. For example, there may be an increase of a specific biomarker in the blood of a patient with a severe injury that wouldn’t be present in a patient with a mild injury. When doctors are better able to determine the severity of an injury, they can make sure patients get the right care at the right time, and that could make a big improvement in their prognoses.
Some of the biomarkers used are the following:
•Known as Banyan BTI (Brain Trauma Indicator), the new test measures levels of two protein biomarkers — ubiquitin carboxy-terminal hydrolase-L1 and glial fibrillary acidic protein — that are released from the brain into blood within 12 hours of head injury.
The Brain Trauma Indicator blood test the levels of two proteins, UCH-L1 and GFAP. Upon brain injury, these proteins are released from the brain into the blood. If found at elevated levels, brain damage, with intracranial lesions, normally otherwise only visible on a CT scan, is suggested. Levels of these blood proteins after mTBI can help predict which patients may have intracranial lesions visible by CT scan and which won’t.
To give approval, FDA used data from a clinical study of 1,947 individual blood samples from adults with suspected TBI and compared blood test results with CT scan results. How did the blood test perform? It was able to predict the presence of intracranial lesions on a CT scan 97.5 percent of the time and those who did not have intracranial lesions on a CT scan 99.6 percent of the time.
•Levels of one protein, called brain-derived neurotrophic factor (BDNF), taken within 24 hours of someone’s head injury, could predict the severity of a TBI and how a patient would fare, they found.
While healthy people averaged 60 nanograms per milliliter of BDNF in their bloodstreams, patients with brain injuries had less than one-third of that amount, averaging less than 20 nanograms per milliliter, and those with the most severe TBIs had even lower levels, around 4 nanograms per milliliter. Moreover, patients with high levels of BDNF had mostly recovered from their injuries six months later. But in patients with the lowest levels of BDNF, symptoms still lingered at follow-up. The results suggest that a test for BDNF levels, administered in the emergency room, could help stratify patients.
•Tau protein (MAPT) possible biomarker for traumatic brain injury . The formation and accumulation of misfolded protein aggregates composed of amyloid-beta (Aβ) and tau. APT is a neuronal protein that plays an important role in axonal stabilization, neuronal development, and neuronal polarity. MAPT release into the CSF and blood has been interpreted as indicative of axonal injury.
It is believed that this biomarker may prove helpful in identifying high-risk patients with mTBI. However, additional studies are needed to establish the diagnostic value of serum tau in detecting traumatic brain injury in patients with mTBI.
(all information compiled from various sources)