Biomarkers in Traumatic Brain Injury

1. Biomarkers in Traumatic Brain Injury
PRESENTED BY​:
DR. ANINDYA SHUVRA MANDAL
1ST YEAR PGT
MD FORENSIC MEDICINE
MEDICAL COLLEGE, KOLKATA
CHAIRPERSON​:
PROF.(DR.)BISWAJIT SUKUL
HEAD OF THE DEPARTMENT
DEPARTMENT OF FORENSIC & STATE MEDICINE
MEDICAL COLLEGE, KOLKATA

2. INTRODUCTION:-
• Traumatic Brain Injury(TBI) – Major source of death and disability
worldwide among children and adults.
• Globally, annual incidents of TBI are estimated 27-69 million.
• In India, nearly 1.5-2million persons are injured and 1million people succumb
to death yearly.
• Road traffic incidents(60%) are the leading cause followed by Falls(20-25%)
and Violence(10%). Alcohol involvement is known to be present among (15-
20%) of TBIs at the time of injury.

3. OBJECTIVE:-
• To study the different biomarkers related to traumatic brain injury.

4. DEFINITION:-
Traumatic Brain Injury (TBI) is a non-degenerative, non-congenital insult to the
brain from an external mechanical force, possibly leading to permanent or
temporary impairment of cognitive, physical and psychosocial functions, with
an associated diminished or altered state of
consciousness.

5. CLASSIFICATION:-
According to location
According to mechanism.
According to severity.
According to pathophysiology.

6. According to location:-
Focal injury- due to contact force, causing scalp injury, skull fracture,
contusions or intracranial haemorrhage.
Diffuse injury- widespread brain damage. e.g. diffuse axonal injury.
-May be temporary or permanent.
-Usually due to acceleration or deacceleration injury.
-Associated with rotation motion.

7. According to mechanism:-
• Open- Open or penetrating injury occurs due to the impact of a bullet, knife or
other sharp objects.
• Closed- injury to the brain caused by an outside force without any penetration
of the skull.
e.g. acceleration-deceleration movement (causes the brain
To move inside the skull and slam against its hard inner
part of the skull)
- Domestic violence, child abuse and shaken baby syndrome

8. According to severity:-

9. According to pathophysiology:-
• Primary Injury – induced by mechanical force.
- Occurs at the moment of injury.
- Forces can cause intracranial haemorrhage, diffuse vascular injury and injury to
cranial nerves.
• Secondary Injury- occurs hours or days after a traumatic event.
- Injury from impairment in cerebral blood flow (CBF) after TBI.
- Inadequate perfusion – cellular ion pumps fail- cascade involving intracellular
Ca & Na
- Resultant Ca and Na overload – cellular destruction.
- Excessive release of excitatory AA - exacerbates ion pump failure

10. Cascade
continues
Cells die
Free radical
formation,
proteolysis &
lipid
peroxidation
Ultimately
cause
neuronal
death.

11. WHY THE NEED OF BIOMARKERS??
• TBI is difficult to diagnose even with imaging techniques.
• No definitive laboratory test to support diagnosis.
• CT Scan - gold standard diagnostic procedure for initial evaluation of TBI.
• Can’t predict neuropsychiatric outcome in mild TBI patients.
• When neuroimaging is limited.
• Establish a correlation between brain-specific markers with TBI.
• Ideal marker – both brain-specific and sensitive. Correlate quantitatively and
qualitatively with injury severity.
• Traditional techniques for measurement- ELISA, RIA, Mass Spectrometry.

12. S – 100B
• 1st isolated by Moore in 1965 from bovine brain.
• Solubility in 100% saturated ammonium sulfate at neutral pH.
• Calcium binding proteins localized in astroglial & Schwann cells.
• Marker of astroglial tissue.
• Also found in adipocytes, chondrocytes & melanoma.
• Half life – 30 minutes.

13. Contd…
• Initially increased values – primary brain injury.
• Elevated S100B levels increase injury severity, poor clinical outcomes, and
increased mortality.
• S100B can predict Post-Concussion Syndrome after Mild TBI
• Mild TBI - >0.2µg/l within 6 hours of trauma – predicts long-term
neuropsychological dysfunction.

14. Contd…
• Moderate to severe TBI - higher and long-lasting release of S-100B.
– >2µg/l predicts unfavorable outcome.
• Greatest diagnostic value - 90% sensitivity and 99% negative predictive value
for intracranial pathology.
• Levels increase with age.
• Insignificant gender variability.
• Levels vary with intensive exercise and multiple trauma .

15. Neuron specific enolase (NSE)
• 1st described by Moore & McGregor in 1965.
• Glycolytic enzyme.
• Founds in the cytoplasm of neurons and peripheral neuroendocrine cells.
• Marker of neuronal tissue.
• Half life – 48 hours.

16. Contd…
• Increased serum levels indicate secondary brain damage.
• Levels over 10µg/l is considered pathologic.
• Increases in CSF of children significantly after severe TBI

17. GLIAL FIBRILLARY ACIDIC PROTEIN(GFAP)
• 1st isolated in 1971.
• Intermediate filamental protein.
• Found primarily in the astroglial cytoskeleton.
• Not found outside CNS – highly brain-specific.
• Levels over 0.033µg/l – pathologic

18. Contd…
• Earliest – 1 day post trauma.
• Remains elevated up to 4 weeks post-trauma.
• Helps to predict focal v/s diffuse brain injury.
• Values significantly higher in non- survivors post-TBI than survivors.
• Prediction of morbidity and mortality.
• Remains normal in multi-trauma patients without TBI

19. UBIQUITION C – TERMINALHYDROLASE L1
• 1st discovered in 1980.
• UCH – L1 is a globular protein making up 1-5% of total neuronal proteins.
• Marker for severe TBI.
• Levels rise within a few hours post-injury and decline fast.
• Peak is seen 8 hours after trauma.
• Ratio of GFAP to UCH –L1 – d/d between focal and diffuse TBI..

20. MYELIN BASIC PROTEIN (MBP)
• It exists in oligodendroglia.
• TBI Axonal damage release of MBP in the blood
• Release 1-3 days after the injury.
• Elevated serum MBP may last up to 2 weeks indicating poor outcome.
• There is an association between increased MBP levels and the increased risk of
mortality.
• It is not suitable for emergency room screening biomarkers due to delayed
release and doesn’t correlate with GCS.
• Less than 4ng/ml is normal for MBP in the CSF.

21. NEUROFILAMENTS PROTEINS(NFP)
• Neuronal cytoskeleton composed of NFP.
• Localized in axons – regulate structure and diameter of neurons.
• NF released into extracellular space then to CSF and Blood.
• Due to NF specificity for neurons and axons, the presence of NF
in ECS indicates neuronal death and axonal disintegration.
• NF-L and NF-H increase in the first 2 weeks after severe TBI,
indicating poor outcomes.

22. CLEAVED TAU PROTEIN
• Tau is a microtubule-associated protein(MAP) expressed mainly in the neurons
to stabilize axonal microtubules.
• Tau cleaved into fragments after cellular injury.
• Localized in neuronal axons.
• Released after diffuse axonal injury.
• Detection within 1st 10 hours of injury – risk of intracranial injury and peaks 2
days after TBI.
• Also in Alzheimer's disease and chronic encephalopathy.

23. SPECTRIN BREAKDOWN PRODUCTS (SBP)
• Cytoskeletal protein
• Maintains cell membrane integrity & cytoskeletal structure.
• Found in axons and presynaptic terminals.
• Injury Calpains & Caspases cleave Spectrin to SBP.
• α -II Spectrin fragment – detected in concussion.
• Post-concussion levels increase 2.5 folds above baseline.
• Remains elevated from 1 hour to 6 days.

24. VIMENTIN
• Cytoskeletal component of astroglial cells.
• Expressed by immature astrocytes in the early phase of CNS development.
• Elevated Vimentin expression in cortical lesions.
• Earliest – 22 hours post trauma.
• Remains elevated up to 4 weeks post-trauma.

25. TENASCIN
• Extracellular matrix protein.
• Synthesized and released by immature astrocytes.
• Increased expression after open brain injury.
• Earliest – 7 days post-trauma.

26. LIMITATIONS
• Research is going on but no biomarker is discovered that is specific ONLY for
TBI.
• Sex, age and racial variability – not documented.
• Concentration of markers in CSF – depends on volume and flow.
• Kidney and liver functions affect the clearance of markers.
• Also occurs in other pathological conditions – ischemia & and brain tumors.

27. CONCLUSION:-
• Due to the heterogeneous nature of TBI aetiology, pathology, and clinical
course, current conventional TBI biomarkers have several limitations in the
clinical setting and TBI research.
• Neuroimaging by CT and MRI is limited to detecting gross head injuries without
the minute neural injuries or the structural changes and their high costs.
• Fluid biomarkers seem reliable and more plausible for accurate correlation
with neuronal, axonal, or glial cell injuries. However, current conventional fluid
proteins might exist in small amounts that require sensitive assays and might
even be undetectable.

28. REFERENCE:-
• Eric Peter Thelin, David W Nelson, Bo-Michael Bellander. A review of the clinical Utility of serum S100B
proteins levels in the assessment of traumatic brain injury. Acta Neurochir (2017); 159:209-225.
• Hazem S Ghaith, Asmaa Ahmed Nawar, Mohamed Diaa Gabra etc. A literature Review of Traumatic Brain
Injury. Molecular Neurobiology (2022); 59:4141-4158.
• Mollayeva T, Mollayeva S, Colantonio A (2018) Traumatic brain injury: sex, gender and intersecting
vulnerabilities. Nat Rev Neurol 14(12):711–722.
• Ladak AA, Enam SA, Ibrahim MT (2019) A review of the molecular mechanisms of traumatic brain injury.
World Neurosurg 131:126–132.
• Karnati HK, Garcia JH, Tweedie D, Becker RE, Kapogiannis D, Greig NH (2019) Neuronal enriched extracellular
vesicle proteins as biomarkers for traumatic brain injury. J Neurotrauma 36(7):975–987.
• Wang KK, Yang Z, Zhu T, Shi Y, Rubenstein R, Tyndall JA, Manley GT (2018) An update on diagnostic and
prognostic biomarkers for traumatic brain injury. Expert Rev Mol Diagn 18(2):165–180.
• Zetterberg H, Blennow K (2016) Fluid biomarkers for mild traumatic brain injury and related conditions. Nat
Rev Neurol 12(10):563–574.
• Lorente L (2017) Biomarkers associated with the outcome of traumatic brain injury patients. Brain Sci 7(11).

29. THANK YOU