1. The primary aim of this study is to discover new biomarkers through proteomics analysis in brain tissue, serum, and cerebro-spinal fluid (CSF) that may allow for the following aspects:
Early identification of those patients who experience secondary brain damage after traumatic brain injury. Since the primary damage is not suitable to be eliminated through therapeutic intervention, it is the ultimate goal of neuroprotective approaches to detect the secondary damage at an early stage in order to start the therapeutic intervention in time.
a correlation of biomarkers with the results of routine neuromonitoring, such as measurement of intracranial pressure, cerebral perfusion pressure or electrophysiological assessment. This would allow defining profiles that could be associated with the occurrence of secondary damage.
the early detection of groups of patients who will benefit from more intensive rehabilitation in the longer term.
2. The identification of bioparameters for TBI patients with a high risk of developing secondary damage could lead to relevant consequences during the acute treatment phase such as:
to intensify the neuromonitoring measures, e.g. by the implantation of bilateral brain cerebral oxygen concentration (ptiO2) measuring probes.
early change or intensification of the conservative therapy measures, e.g. by a deep neuroprotective sedation, or an extension of the sedation phase.
to a specific implementation of radiological examinations, e.g. of CCT angiography and CCT perfusion examinations.
3. The identification of biomarkers in TBI patients associated with better prognosis allows:
the development of individualized rehabilitation concepts, with
a subsequent faster functional recovery of patients
and a faster social and professional reintegration of the patients
4. Identification of the subgroup of the so-called "late winners", i.e. the TBI patients, who later on have a significantly better outcome over time. This patient group would particularly benefit from a specifically prolonged rehabilitation phase. This higher investment in a longer rehabilitation measure could count on a better outcome in the long term.
With intracerebral contusion-bleeding and/or intraparenchymatous hemorrhage, both necessitating of surgical evacuation, an combined ICP (intracranial pressure)/IVD (intraventricular drain) probe is placed in the anterior horn of the lateral ventricles and a ptiO2 probe in the area of the so-called "penumbra" (i.e., rim) of the contusion bleeding. Contusioned brain tissue, in those patients with clear medical necessity to be surgically treated, will be biopsied as part of the removal of the bleeding, as well as CSF, which is taken standard and routinely through the IVD, will be subsequently analyzed in our Neurosurgical Research Laboratory as well as in the Proteomics Center of the Ruhr University Bochum.
Assays to identify new biomarkers:
Detection and semi-quantitative determination sSHT-associated index parameter potentially describing the secondary brain damage. The expression analysis in the contusioned tissue of proteins of the nucleocytoplasmic and intra/extracellular transport is carried out semiquantitatively by means of immunohistochemistry and immunofluorescence. Similarly, proteins related with hypoxia, dysregulation of the neurovascular unit, cell edema, apoptosis/necrosis and destruction of the intracellular structure, astroglia and cytoskeletons will be assessed.
Furthermore, an analysis of the neuroinflammation processes will be aimed. For this purpose, the cerebrospinal fluid is also checked for a possible increase of immune cells. A sandwich ELISA is used to study immunoglobulins, proteins of nucleocytoplasmic transport in the blood and cerebrospinal fluid.
2. Proteome study: Global analysis to identify potential new biomarkers and validation by targeted analysis.
For the detection of proteins, which should be investigated more closely as new biomarker candidates and could be involved in the pathogenesis of secondary brain damages, the samples of the TBI patients, samples from the control group and/or samples from different potential prognosis groups (i.e. early outcome vs. late outcome), will be individually analyzed by mass spectrometric high-throughput proteomics methods. These measurements, performed by the MPC, allow a wide proteomic analysis in a sample to be quantified using appropriate bioinformatics methods used by Medical Bioinformatics (MB) Department.
Before the raw data can be analyzed using these methods, the MB performs standard quality assurance measures.
For protein identification, the measured MS spectra are first compared by special software with theoretical spectra of human peptides in order to obtain peptide-to-spectrum assignments, the so-called peptide-spectrum matches (PSMs), defined as precisely as possible.
The biomarker candidates detected by the above high-throughput analyzes are then measured by the MPC using targeted proteomics and validated by the MB.
Once a robust set of biomarker candidates is available, their suitability for diagnostic use can be verified by discriminant analysis methods. Finally, the validated biomarker candidates are analyzed by the MB using other computer-aided methods. The aim is to support validation and further hypothesis formation via the results of enrichment and pathway analyzes, in which biomarker candidates are classified in pre-existing data bases.
Recruited patients will be at least for two years followed-up and clinically assessed.
26 Feb 2018