Biomarkers for the clinical differential diagnosis in traumatic brain injury--a systematic review

Increased [18F]Fluorodeoxyglucose Uptake in the Left Pallidum in Military Veterans with Blast-Related Mild Traumatic Brain Injury: Potential as an Imaging Biomarker and Mediation with Executive Dysfunction and Cognitive Impairment

Blast-related mild traumatic brain injury (blast-mTBI) can result in a spectrum of persistent symptoms leading to substantial functional impairment and reduced quality of life. Clinical evaluation and discernment from other conditions common to military service can be challenging and subject to patient recall bias and the limitations of available assessment measures. The need for objective biomarkers to facilitate accurate diagnosis, not just for symptom management and rehabilitation but for prognostication and disability compensation purposes is clear. Toward this end, we compared regional brain [18F]fluorodeoxyglucose-positron emission tomography ([18F]FDG-PET) intensity-scaled uptake measurements and motor, neuropsychological, and behavioral assessments in 79 combat Veterans with retrospectively recalled blast-mTBI with 41 control participants having no lifetime history of TBI. Using an agnostic and unbiased approach, we found significantly increased left pallidum [18F]FDG-uptake in Veterans with blast-mTBI versus control participants, p < 0.0001; q = 3.29 × 10-9 [Cohen's d, 1.38, 95% confidence interval (0.96, 1.79)]. The degree of left pallidum [18F]FDG-uptake correlated with the number of self-reported blast-mTBIs, r2 = 0.22; p < 0.0001. Greater [18F]FDG-uptake in the left pallidum provided excellent discrimination between Veterans with blast-mTBI and controls, with a receiver operator characteristic area under the curve of 0.859 (p < 0.0001) and likelihood ratio of 21.19 (threshold:SUVR ≥ 0.895). Deficits in executive function assessed using the Behavior Rating Inventory of Executive Function-Adult Global Executive Composite T-score were identified in Veterans with blast-mTBI compared with controls, p < 0.0001. Regression-based mediation analyses determined that in Veterans with blast-mTBI, increased [18F]FDG-uptake in the left pallidum-mediated executive function impairments, adjusted causal mediation estimate p = 0.021; total effect estimate, p = 0.039. Measures of working and prospective memory (Auditory Consonant Trigrams test and Memory for Intentions Test, respectively) were negatively correlated with left pallidum [18F]FDG-uptake, p < 0.0001, with mTBI as a covariate. Increased left pallidum [18F]FDG-uptake in Veterans with blast-mTBI compared with controls did not covary with dominant handedness or with motor activity assessed using the Unified Parkinson's Disease Rating Scale. Localized increased [18F]FDG-uptake in the left pallidum may reflect a compensatory response to functional deficits following blast-mTBI. Limited imaging resolution does not allow us to distinguish subregions of the pallidum; however, the significant correlation of our data with behavioral but not motor outcomes suggests involvement of the ventral pallidum, which is known to regulate motivation, behavior, and emotions through basal ganglia-thalamo-cortical circuits. Increased [18F]FDG-uptake in the left pallidum in blast-mTBI versus control participants was consistently identified using two different PET scanners, supporting the generalizability of this finding. Although confirmation of our results by single-subject-to-cohort analyses will be required before clinical deployment, this study provides proof of concept that [18F]FDG-PET bears promise as a readily available noninvasive biomarker for blast-mTBI. Further, our findings support a causative relationship between executive dysfunction and increased [18F]FDG-uptake in the left pallidum.

A Narrative Review of Existing and Developing Biomarkers in Acute Traumatic Brain Injury for Potential Military Deployed Use

INTRODUCTION

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality in both adult civilian and military populations. Currently, diagnostic and prognostic methods are limited to imaging and clinical findings. Biomarker measurements offer a potential method to assess head injuries and help predict outcomes, which has a potential benefit to the military, particularly in the deployed setting where imaging modalities are limited. We determine how biomarkers such as ubiquitin C-terminal hydrolase-L1 (UCH-L1), glial fibrillary acidic protein (GFAP), S100B, neurofilament light chain (NFL), and tau proteins can offer important information to guide the diagnosis, acute management, and prognosis of TBI, specifically in military personnel.

MATERIALS AND METHODS

We performed a narrative review of peer-reviewed literature using online databases of Google Scholar and PubMed. We included articles published between 1988 and 2022.

RESULTS

We screened a total of 73 sources finding a total of 39 original research studies that met inclusion for this review. We found five studies that focused on GFAP, four studies that focused on UCH-L1, eight studies that focused on tau proteins, six studies that focused on NFL, and eight studies that focused on S100B. The remainder of the studies included more than one of the biomarkers of interest.

CONCLUSIONS

TBI occurs frequently in the military and civilian settings with limited methods to diagnose and prognosticate outcomes. We highlighted several promising biomarkers for these purposes including S100B, UCH-L1, NFL, GFAP, and tau proteins. S100B and UCH-L1 appear to have the strongest data to date, but further research is necessary. The robust data that explain the optimal timing and, more importantly, trending of these biomarker measurements are necessary before widespread application.

Life After Traumatic Brain Injury: Effects on the Lifestyle and Quality of Life of Community-Dwelling Patients

Persons who have experienced traumatic brain injury (TBI) may encounter a range of changes in their physical, mental, and cognitive functions as well as high fatigue levels. To gain a comprehensive understanding of the challenges faced by persons after TBI, we conducted multi-domain assessments among community-dwelling persons with a history of TBI and compared them with age- and sex-matched controls from the Northeastern Taiwan Community Medicine Research Cohort between 2019 and 2021. A total of 168 persons with TBI and 672 non-TBI controls were not different in terms of demographics, comorbidities, and physiological features. However, compared with the non-TBI group, the TBI group had a distinct lifestyle that involved increased reliance on analgesics (6.9% vs. 15.0%, respectively; p = 0.001) and sleep aids (p = 0.008), which negatively affected their quality of life. Moreover, they consumed more coffee (p < 0.001), tea (p < 0.001), cigarettes (p = 0.002), and betel nuts (p = 0.032) than did the non-TBI group. Notably, the use of coffee had a positive effect on the quality of life of the TBI group (F = 4.034; p = 0.045). Further, compared with the non-TBI group, the TBI group had increased risks of sarcopenia (p = 0.003), malnutrition (p = 0.003), and anxiety (p = 0.029) and reduced blood levels of vitamin D (29.83 ± 10.39 vs. 24.20 ± 6.59 ng/mL, respectively; p < 0.001). Overall, the TBI group had a reduced health-related quality of life, with significant challenges related to physical health, mental well-being, social interactions, pain management, and fatigue levels. Moreover, the TBI group experienced poorer sleep quality and efficiency than did the non-TBI group. In conclusion, persons who have sustained brain injuries that require comprehensive and holistic care that includes lifestyle modification, mental and physical healthcare plans, and increased long-term support from their communities. ClinicalTrials.gov (identifier: NCT04839796).

Post-mortem detection of neuronal and astroglial biochemical markers in serum and urine for diagnostics of traumatic brain injury

Currently available epidemiological data shows that traumatic brain injury (TBI) represents one of the leading causes of death that is associated with medico-legal practice, including forensic autopsy, criminological investigation, and neuropathological examination. Attention focused on TBI research is needed to advance its diagnostics in ante- and post-mortem cases with regard to identification and validation of novel biomarkers. Recently, several markers of neuronal, astroglial, and axonal injury have been explored in various biofluids to assess the clinical origin, progression, severity, and prognosis of TBI. Despite clinical usefulness, understanding their diagnostic accuracy could also potentially help translate them either into forensic or medico-legal practice, or both. The aim of this study was to evaluate post-mortem pro-BDNF, NSE, UCHL1, GFAP, S100B, SPTAN1, NFL, MAPT, and MBP levels in serum and urine in TBI cases. The study was performed using cases (n = 40) of fatal head injury and control cases (n = 20) of sudden death. Serum and urine were collected within ∼ 24 h after death and compared using ELISA test. In our study, we observed the elevated concentration levels of GFAP and MAPT in both serum and urine, elevated concentration levels of S100B and SPTAN1 in serum, and decreased concentration levels of pro-BDNF in serum compared to the control group. The obtained results anticipate the possible implementation of performed assays as an interesting tool for forensic and medico-legal investigations regarding TBI diagnosis where the head injury was not supposed to be the direct cause of death.

The Role of Novel Imaging and Biofluid Biomarkers in Traumatic Axonal Injury: An Updated Review

Traumatic brain injury (TBI) is a leading cause of disability worldwide. Traumatic axonal injury (TAI) is a subtype of TBI resulting from high-impact forces that cause shearing and/or stretching of the axonal fibers in white matter tracts. It is present in almost half of cases of severe TBI and frequently associated with poor functional outcomes. Axonal injury results from axonotomy due to mechanical forces and the activation of a biochemical cascade that induces the activation of proteases. It occurs at a cellular level; hence, conventional imaging modalities often fail to display TAI lesions. However, the advent of novel imaging modalities, such as functional magnetic resonance imaging and fiber tractography, has significantly improved the detection and characteristics of TAI. Furthermore, the significance of several fluid and structural biomarkers has also been researched, while the contribution of omics in the detection of novel biomarkers is currently under investigation. In the present review, we discuss the role of imaging modalities and potential biomarkers in diagnosing, classifying, and predicting the outcome in patients with TAI.

Prognostic Value of Plasma Biomarkers S100B and Osteopontin in Pediatric TBI: A Prospective Analysis Evaluating Acute and 6-Month Outcomes after Mild to Severe TBI

Blood based traumatic brain injury (TBI) biomarkers offer additional diagnostic, therapeutic, and prognostic utility. While adult studies are robust, the pediatric population is less well studied. We sought to determine whether plasma osteopontin (OPN) and S100B alone or in combination predict mortality, head Computed tomography (CT) findings, as well as 6-month functional outcomes after TBI in children. This is a prospective, observational study between March 2017 and June 2021 at a tertiary pediatric hospital. The sample included children with a diagnosed head injury of any severity admitted to the Emergency Department. Control patients sustained trauma-related injuries and no known head trauma. Serial blood samples were collected at admission, as well as at 24, 48, and 72 h. Patient demographics, acute clinical symptoms, head CT, and 6-month follow-up using the Glasgow outcome scale, extended for pediatrics (GOSE-Peds), were also obtained. The cohort included 460 children (ages 0 to 21 years) and reflected the race and sex distribution of the population served. Linear mixed effect models and logistic regressions were utilized to evaluate the trajectory of biomarkers over time and predictors of dichotomous outcomes. Both OPN and S100B correlated with injury severity based on GCS. S100B and OPN showed lower AUC values (0.59) in predicting positive head CT. S100B had the largest AUC (0.87) in predicting mortality, as well as 6-month outcomes (0.85). The combination of the two biomarkers did not add meaningfully to the model. Our findings continue to support the utility of OPN as a marker of injury severity in this population. Our findings also show the importance of S100B in predicting mortality and 6-month functional outcomes. Continued work is needed to examine the influence of age-dependent neurodevelopment on TBI biomarker profiles in children.

Effects of early adjunctive pharmacotherapy on serum levels of brain injury biomarkers in patients with traumatic brain injury: a systematic review of randomized controlled studies

Objectives: Traumatic brain injury (TBI) is one of the top causes of morbidity and mortality worldwide. The review aimed to discuss and summarize the current evidence on the effectiveness of adjuvant neuroprotective treatments in terms of their effect on brain injury biomarkers in TBI patients. Methods: To identify relevant studies, four scholarly databases, including PubMed, Cochrane, Scopus, and Google Scholar, were systematically searched using predefined search terms. English-language randomized controlled clinical trials reporting changes in brain injury biomarkers, namely, neuron-specific enolase (NSE), glial fibrillary acid protein (GFAP), ubiquitin carboxyl-terminal esterase L1 (UCHL₁) and/or S100 beta (S100 ß), were included. The methodological quality of the included studies was assessed using the Cochrane risk-of-bias tool. Results: A total of eleven studies with eight different therapeutic options were investigated; of them, tetracyclines, metformin, and memantine were discovered to be promising choices that could improve neurological outcomes in TBI patients. The most utilized serum biomarkers were NSE and S100 ß followed by GFAP, while none of the included studies quantified UCHL₁. The heterogeneity in injury severity categories and measurement timing may affect the overall evaluation of the clinical efficacy of potential therapies. Therefore, unified measurement protocols are highly warranted to inform clinical decisions. Conclusion: Few therapeutic options showed promising results as an adjuvant to standard care in patients with TBI. Several considerations for future work must be directed towards standardizing monitoring biomarkers. Investigating the pharmacotherapy effectiveness using a multimodal biomarker panel is needed. Finally, employing stratified randomization in future clinical trials concerning potential confounders, including age, trauma severity levels, and type, is crucial to inform clinical decisions. Clinical Trial Registration: [https://www.crd.york.ac.uk/prospero/dis], identifier [CRD42022316327].

Comparing blood biomarkers to clinical decision rules to select patients suspected of traumatic brain injury for head computed tomography

INTRODUCTION

Traumatic brain injury (TBI) is a major public health concern in the U.S. Recommendations for patients admitted in the emergency department (ED) to receive head computed tomography (CT) scan are currently guided by various clinical decision rules.

OBJECTIVE

To compare how a blood biomarker approach compares with clinical decision rules in terms of predicting a positive head CT in adult patients suspected of TBI.

METHODS

We retrospectively identified patients transported to our emergency department and underwent a noncontrast head CT due to suspicion of TBI and who had blood samples available. Published thresholds for serum and plasma glial fibrillary acidic protein (GFAP), ubiquitin carboxyl-terminal hydrolase-L1 (UCH-L1), and serum S100β were used to make CT recommendations. These blood biomarker-based recommendations were compared to those achieved under widely used clinical head CT decision rules (Canadian, New Orleans, NEXUS II, and ACEP Clinical Policy).

RESULTS

Our study included 463 patients, of which 122 (26.3%) had one or more abnormalities presenting on head CT. Individual blood biomarkers achieved high negative predictive value (NPV) for abnormal head CT findings (88%-98%), although positive predictive value (PPV) was consistently low (25%-42%). A composite biomarker-based decision rule (GFAP+UCH-L1)'s NPV of 100% and PPV of 29% were comparable or better than those achieved under the clinical decision rules.

CONCLUSION

Blood biomarkers perform at least as well as clinical rules in terms of selecting TBI patients for head CT and may be easier to implement in the clinical setting. A prospective study is necessary to validate this approach.

Multiplex Assessment of Serum Chemokines CCL2, CCL5, CXCL1, CXCL10, and CXCL13 Following Traumatic Brain Injury

Chemokines may promote neuroinflammation following traumatic brain injury (TBI), thereby exacerbating secondary injury. This study was designed to investigate the contributions of chemokines (CCL2, CCL5, CXCL1, CXCL10, and CXCL13) to TBI severity and clinical outcome. Peripheral blood was drawn from 92 TBI patients on admission, and 40 controls were recruited. Serum concentrations of CCL2, CCL5, CXCL1, CXCL10, and CXCL13 on admission were measured by ELISA. Preoperative clinical severity was evaluated using the Glasgow Coma Scale (GCS), and clinical outcome at 90 days post-TBI was evaluated using the Glasgow Outcome Scale (GOS). The associations were evaluated by calculating Spearman's correlation coefficients. A binary logistic regression model was used to identify clinicodemographic factors influencing outcome, and ROC curves were constructed. Serum concentrations of CCL2, CCL5, CXCL1, CXCL10, and CXCL13 were elevated significantly after TBI and negatively correlated with GCS and GOS scores except CCL5. CCL2 may be considered as an independent predictor to predict severity and outcome. Moreover, combination of GCS score, CCL2, and CXCL10 can be a better assessment prognosis of moderate and severe TBI.

Review: Emerging Eye-Based Diagnostic Technologies for Traumatic Brain Injury

The study of ocular manifestations of neurodegenerative disorders, Oculomics, is a growing field of investigation for early diagnostics, enabling structural and chemical biomarkers to be monitored overtime to predict prognosis. Traumatic brain injury (TBI) triggers a cascade of events harmful to the brain, which can lead to neurodegeneration. TBI, termed the "silent epidemic" is becoming a leading cause of death and disability worldwide. There is currently no effective diagnostic tool for TBI, and yet, early-intervention is known to considerably shorten hospital stays, improve outcomes, fasten neurological recovery and lower mortality rates, highlighting the unmet need for techniques capable of rapid and accurate point-of-care diagnostics, implemented in the earliest stages. This review focuses on the latest advances in the main neuropathophysiological responses and the achievements and shortfalls of TBI diagnostic methods. Validated and emerging TBI-indicative biomarkers are outlined and linked to ocular neuro-disorders. Methods detecting structural and chemical ocular responses to TBI are categorised along with prospective chemical and physical sensing techniques. Particular attention is drawn to the potential of Raman spectroscopy as a non-invasive sensing of neurological molecular signatures in the ocular projections of the brain, laying the platform for the first tangible path towards alternative point-of-care diagnostic technologies for TBI.

Brain Trauma Imaging

Imaging of mild traumatic brain injury (TBI) using conventional techniques such as CT or MRI often results in no specific imaging correlation that would explain cognitive and clinical symptoms. Molecular imaging of mild TBI suggests that secondary events after injury can be detected using PET. However, no single specific pattern emerges that can aid in diagnosing the injury or determining the prognosis of the long-term behavioral profiles, indicating the heterogeneous and diffuse nature of TBI. Chronic traumatic encephalopathy, a primary tauopathy, has been shown to be strongly associated with repetitive TBI. In vivo data on the available tau PET tracers, however, have produced mixed results and overall low retention profiles in athletes with a history of repetitive mild TBI. Here, we emphasize that the lack of a mechanistic understanding of chronic TBI has posed a challenge when interpreting the results of molecular imaging biomarkers. We advocate for better target identification, improved analysis techniques such as machine learning or artificial intelligence, and novel tracer development.

Inhibition of Caspase 3 and Caspase 9 Mediated Apoptosis: A Multimodal Therapeutic Target in Traumatic Brain Injury

Traumatic brain injury (TBI) is one of the significant causes of death and morbidity, and it is hence a focus of translational research. Apoptosis plays an essential part in the pathophysiology of TBI, and its inhibition may help overcome TBI's negative consequences and improve functional recovery. Although physiological neuronal death is necessary for appropriate embryologic development and adult cell turnover, it can also drive neurodegeneration. Caspases are principal mediators of cell death due to apoptosis and are critical for the required cleavage of intracellular proteins of cells committed to die. Caspase-3 is the major executioner Caspase of apoptosis and is regulated by a range of cellular components during physiological and pathological conditions. Activation of Caspase-3 causes proteolyzation of DNA repair proteins, cytoskeletal proteins, and the inhibitor of Caspase-activated DNase (ICAD) during programmed cell death, resulting in morphological alterations and DNA damage that define apoptosis. Caspase-9 is an additional crucial part of the intrinsic pathway, activated in response to several stimuli. Caspases can be altered post-translationally or by modulatory elements interacting with the zymogenic or active form of a Caspase, preventing their activation. The necessity of Caspase-9 and -3 in diverse apoptotic situations suggests that mammalian cells have at least four distinct apoptotic pathways. Continued investigation of these processes is anticipated to disclose new Caspase regulatory mechanisms with consequences far beyond apoptotic cell death control. The present review discusses various Caspase-dependent apoptotic pathways and the treatment strategies to inhibit the Caspases potentially.

Traumatic Brain Injury Biomarkers, Simulations and Kinetics

This paper reviews the predictive capabilities of blood-based biomarkers to quantify traumatic brain injury (TBI). Biomarkers for concussive conditions also known as mild, to moderate and severe TBI identified along with post-traumatic stress disorder (PTSD) and chronic traumatic encephalopathy (CTE) that occur due to repeated blows to the head during one's lifetime. Since the pathways of these biomarkers into the blood are not fully understood whether there is disruption in the blood-brain barrier (BBB) and the time it takes after injury for the expression of the biomarkers to be able to predict the injury effectively, there is a need to understand the protein biomarker structure and other physical properties. The injury events in terms of brain and mechanics are a result of external force with or without the shrapnel, in the wake of a wave result in local tissue damage. Thus, these mechanisms express specific biomarkers kinetics of which reaches half-life within a few hours after injury to few days. Therefore, there is a need to determine the concentration levels that follow injury. Even though current diagnostics linking biomarkers with TBI severity are not fully developed, there is a need to quantify protein structures and their viability after injury. This research was conducted to fully understand the structures of 12 biomarkers by performing molecular dynamics simulations involving atomic movement and energies of forming hydrogen bonds. Molecular dynamics software, NAMD and VMD were used to determine and compare the approximate thermodynamic stabilities of the biomarkers and their bonding energies. Five biomarkers used clinically were S100B, GFAP, UCHL1, NF-L and tau, the kinetics obtained from literature show that the concentration values abruptly change with time after injury. For a given protein length, associated number of hydrogen bonds and bond energy describe a lower bound region where proteins self-dissolve and do not have long enough half-life to be detected in the fluids. However, above this lower bound, involving higher number of bonds and energy, we hypothesize that biomarkers will be viable to disrupt the BBB and stay longer to be modeled for kinetics for diagnosis and therefore may help in the discoveries of new biomarkers.

Senkyunolide H Affects Cerebral Ischemic Injury through Regulation on Autophagy of Neuronal Cells via P13K/AKT/mTOR Signaling Pathway

Cerebral ischemia (CI) is associated with high global incidence and risk; therefore, its rapid and reliable therapeutic management is essential for protecting patients' lives and improving health. Senkyunolide H (SH) is remarkably effective against phlebosclerosis, oxidation, and apoptosis. Blood-brain barrier is the main obstacle impeding the delivery of drugs and xenobiotics to brain areas. Drugs' loading in nanoparticles can overcome the blood-brain barrier obstacle and thus directly and completely act on brain tissue, and such a loading can also change the half-life of drugs in vivo and lower the dosage requirement of drugs. In this study, we loaded the SH in lipid nanoparticles to improve its delivery to the brain for the therapy of CI. Thus, this study preliminarily analyzed the mechanism of SH-loaded nanoparticles in CI. The SH-loaded lipid nanoparticles were prepared and characterized with electron microscopy and PS potentiometery. The SH-loaded nanoparticles were intraperitoneally administered to CI-induced rats and brain tissue water content, and neuronal apoptosis and autophagy-associated proteins were determined. Our assays revealed SH-loaded nanoparticle's ability to reduce nerve injury and brain tissue water content in rats with CI and inhibit the apoptosis and autophagy of their neuronal cells (NCs). Additionally, under intervention with SH-loaded nanoparticles, P13K/AKT/mTOR pathway-associated proteins in brain tissue of rats decreased. As the assay results showed, SH-loaded nanoparticles can suppress the autophagy of NCs through medicating P13K/AKT/mTOR pathway and lower apoptosis, thus delivering the effect of treating CI. Results of this study indicate SH-loaded nanoparticles as promising strategy for delivery SH to brain areas for treating CI.

Density of TMEM119-positive microglial cells in postmortem cerebrospinal fluid as a surrogate marker for assessing complex neuropathological processes in the CNS

Routine coronal paraffin-sections through the dorsal frontal and parieto-occipital cortex of a total of sixty cases with divergent causes of death were immunohistochemically (IHC) stained with an antibody against TMEM119. Samples of cerebrospinal fluid (CSF) of the same cases were collected by suboccipital needle-puncture, subjected to centrifugation and processed as cytospin preparations stained with TMEM119. Both, cytospin preparations and sections were subjected to computer-assisted density measurements. The density of microglial TMEM119-positive cortical profiles correlated with that of cytospin results and with the density of TMEM119-positive microglial profiles in the medullary layer. There was no statistically significant correlation between the density of medullary TMEM119-positive profiles and the cytospin data. Cortical microglial cells were primarily encountered in supragranular layers I, II, and IIIa and in infragranular layers V and VI, the region of U-fibers and in circumscribed foci or spread in a diffuse manner and high density over the white matter. We have evidence that cortical microglia directly migrate into CSF without using the glympathic pathway. Microglia in the medullary layer shows a strong affinity to the adventitia of deep vessels in the myelin layer. Selected rapidly fatal cases including myocardial infarcts and drowning let us conclude that microglia in cortex and myelin layer can react rapidly and its reaction and migration is subject to pre-existing external and internal factors. Cytospin preparations proved to be a simple tool to analyze and assess complex changes in the CNS after rapid fatal damage. There is no statistically significant correlation between cytospin and postmortem interval. Therefore, the quantitative analyses of postmortem cytospins obviously reflect the neuropathology of the complete central nervous system. Cytospins provide forensic pathologists a rather simple and easy to perform method for the global assessment of CNS affliction.

Progress Toward a Multiomic Understanding of Traumatic Brain Injury: A Review

Traumatic brain injury (TBI) is not a single disease state but describes an array of conditions associated with insult or injury to the brain. While some individuals with TBI recover within a few days or months, others present with persistent symptoms that can cause disability, neuropsychological trauma, and even death. Understanding, diagnosing, and treating TBI is extremely complex for many reasons, including the variable biomechanics of head impact, differences in severity and location of injury, and individual patient characteristics. Because of these confounding factors, the development of reliable diagnostics and targeted treatments for brain injury remains elusive. We argue that the development of effective diagnostic and therapeutic strategies for TBI requires a deep understanding of human neurophysiology at the molecular level and that the framework of multiomics may provide some effective solutions for the diagnosis and treatment of this challenging condition. To this end, we present here a comprehensive review of TBI biomarker candidates from across the multiomic disciplines and compare them with known signatures associated with other neuropsychological conditions, including Alzheimer’s disease and Parkinson’s disease. We believe that this integrated view will facilitate a deeper understanding of the pathophysiology of TBI and its potential links to other neurological diseases.

Clinical-Pathological Study on Expressions β-APP, GFAP, NFL, Spectrin II, CD68 to Verify Diffuse Axonal Injury Diagnosis, Grade and Survival Interval

Traumatic brain injury (TBI) is one of the leading causes of death worldwide, particularly in young people. Diffuse axonal injuries (DAI) are the result of strong rotational and translational forces on the brain parenchyma, leading to cerebral oedema and neuronal death. DAI is typically characterized by coma without focal lesions at presentation and is defined by localized axonal damage in multiple regions of the brain parenchyma, often causing impairment of cognitive and neuro-vegetative function. Following TBI, axonal degeneration has been identified as a progressive process that begins with the disruption of axonal transport, leading subsequently to axonal swelling, axonal ballooning, axonal retraction bulges, secondary disconnection and Wallerian degeneration. The objective of this paper is to report on a series of patients who have suffered fatal traumatic brain injury, in order to verify neurological outcomes in dynamics, relative to the time of injury, using antibodies for neurofilament (NFL), spectrin II, beta-amyloid (β-APP), glial fibrillary acidic protein (GFAP) and cluster of differentiation 68 (CD68). From the studied cases, a total of 50 cases were chosen, which formed two study groups. The first study group comprises 30 cases divided according to survival interval. The control group comprises 20 cases with no history of traumatic brain injury. Cardiovascular disease and history of stroke, cases suffering from loss of vital functions, a post-traumatic survival time of less than 15 min, autolysis and putrefaction were established as criteria for exclusion. Based on their expression, we tested for diagnosis and degree of DAI as a strong predictor of mortality. Immunoreactivity was significantly increased in the DAI group compared to the control group. The earliest changes were recorded for GFAP and CD68 immunolabeling, followed by β-APP, spectrin II and NFM. The most intense changes in immunostaining were recorded for spectrin II. Comparative analysis of brain apoptosis, reactive astrocytosis and inflammatory reaction using specific immunohistochemical markers can provide important information on diagnosis of DAI and prognosis, and may elucidate the timing of the traumatic event in traumatic brain injury.

Towards a Point-of-Care (POC) Diagnostic Platform for the Multiplex Electrochemiluminescent (ECL) Sensing of Mild Traumatic Brain Injury (mTBI) Biomarkers

Globally, 70 million people are annually affected by TBI. A significant proportion of all TBI cases are actually mild TBI (concussion, 70-85%), which is considerably more difficult to diagnose due to the absence of apparent symptoms. Current clinical practice of diagnosing mTBI largely resides on the patients' history, clinical aspects, and CT and MRI neuroimaging observations. The latter methods are costly, time-consuming, and not amenable for decentralized or accident site measurements. As an alternative (and/or complementary), mTBI diagnostics can be performed by detection of mTBI biomarkers from patients' blood. Herein, we proposed two strategies for the detection of three mTBI-relevant biomarkers (GFAP, h-FABP, and S100β), in standard solutions and in human serum samples by using an electrochemiluminescence (ECL) immunoassay on (i) a commercial ECL platform in 96-well plate format, and (ii) a "POC-friendly" platform with disposable screen-printed carbon electrodes (SPCE) and a portable ECL reader. We further demonstrated a proof-of-concept for integrating three individually developed mTBI assays ("singleplex") into a three-plex ("multiplex") assay on a single SPCE using a spatially resolved ECL approach. The presented methodology demonstrates feasibility and a first step towards the development of a rapid POC multiplex diagnostic system for the detection of a mTBI biomarker panel on a single SPCE.

Value of brain damage biomarkers in cerebrospinal fluid in neonates with hypoxic-ischemic brain injury

Hypoxic-ischemic encephalopathy is one of the leading causes of death and neurological disability worldwide. A key issue in neonates with hypoxic-ischemic encephalopathy is accurately establishing the occurrence and severity of brain lesions soon after a perinatal hypoxic-ischemic event. This is crucial to help with prognosis; guide clinical decision-making, including the use of other therapies; and improve family counseling. Neurobiochemical markers may offer a quantitative approximation for estimating the severity of brain damage and identifying infants who have a high risk of further neurological disability. In addition, they should help identify those neonates who would benefit most from the implementation of other neuroprotective and neuroreparative interventions. Despite considerable progress in this area, relatively few studies have been aimed at examining the clinical utility of brain-specific proteins in cerebrospinal fluid, an important opening to characterizing pathological phenomena associated with hypoxic-ischemic brain injury.

Quantitative Proteomics Reveals the Dynamic Pathophysiology Across Different Stages in a Rat Model of Severe Traumatic Brain Injury

Background

Severe traumatic brain injury (TBI) has become a global health problem and causes a vast worldwide societal burden. However, distinct mechanisms between acute and subacute stages have not been systemically revealed. The present study aimed to identify differentially expressed proteins in severe TBI from the acute to subacute phase.

Methods

Sixty Sprague Dawley (SD) rats were randomly divided into sham surgery and model groups. The severe TBI models were induced by the controlled cortical impact (CCI) method. We evaluated the neurological deficits through the modified neurological severity score (NSS). Meanwhile, H&E staining and immunofluorescence were performed to assess the injured brain tissues. The protein expressions of the hippocampus on the wounded side of CCI groups and the same side of Sham groups were analyzed by the tandem mass tag-based (TMT) quantitative proteomics on the third and fourteenth days. Then, using the gene ontology (GO), Kyoto encyclopedia of genes and genomes (KEGG), and protein–protein interaction (PPI), the shared and stage-specific differentially expressed proteins (DEPs) were screened, analyzed, and visualized. Eventually, target proteins were further verified by Western blotting (WB).

Results

In the severe TBI, the neurological deficits always exist from the acute stage to the subacute stage, and brain parenchyma was dramatically impaired in either period. Of the significant DEPs identified, 312 were unique to the acute phase, 76 were specific to the subacute phase, and 63 were shared in both. Of the 375 DEPs between Sham-a and CCI-a, 240 and 135 proteins were up-regulated and down-regulated, respectively. Of 139 DEPs, 84 proteins were upregulated, and 55 were downregulated in the Sham-s and CCI-s. Bioinformatics analysis revealed that the differential pathophysiology across both stages. One of the most critical shared pathways is the complement and coagulation cascades. Notably, three pathways associated with gastric acid secretion, insulin secretion, and thyroid hormone synthesis were only enriched in the acute phase. Amyotrophic lateral sclerosis (ALS) was significantly enriched in the subacute stage. WB experiments confirmed the reliability of the TMT quantitative proteomics results.

Conclusion

Our findings highlight the same and different pathological processes in the acute and subacute phases of severe TBI at the proteomic level. The results of potential protein biomarkers might facilitate the design of novel strategies to treat TBI.

Deficiency in Androgen Receptor Aggravates Traumatic Brain Injury-Induced Pathophysiology and Motor Deficits in Mice

Androgens have been shown to have a beneficial effect on brain injury and lower reactive astrocyte expression after TBI. Androgen receptors (ARs) are known to mediate the neuroprotective effects of androgens. However, whether ARs play a crucial role in TBI remains unknown. In this study, we investigated the role of ARs in TBI pathophysiology, using AR knockout (ARKO) mice. We used the controlled cortical impact model to produce primary and mechanical brain injuries and assessed motor function and brain-lesion volume. In addition, the AR knockout effects on necrosis and autophagy were evaluated after TBI. AR knockout significantly increased TBI-induced expression of the necrosis marker alpha-II-spectrin breakdown product 150 and astrogliosis marker glial fibrillary acidic protein. In addition, the TBI-induced astrogliosis increase in ARKO mice lasted for three weeks after a TBI. The autophagy marker Beclin-1 was also enhanced in ARKO mice compared with wild-type mice after TBI. Our results also indicated that ARKO mice showed a more unsatisfactory performance than wild-type mice in a motor function test following TBI. Further, they were observed to have more severe lesions than wild-type mice after injury. These findings strongly suggest that ARs play a role in TBI.

Bedside and laboratory neuromonitoring in neonatal encephalopathy

Several bedside and laboratory neuromonitoring tools are currently used in neonatal encephalopathy (NE) to assess 1) brain function [amplitude-integrated electroencephalogram (aEEG) and EEG], 2) cerebral oxygenation delivery and consumption [near-infrared spectroscopy (NIRS)] and 3) blood and cerebrospinal fluid biomarkers. The aim of the review is to provide the role of neuromonitoring in understanding the development of brain injury in these newborns and better predict their long-term outcome. Simultaneous use of these monitoring modalities may improve our ability to provide meaningful prognostic information regarding ongoing treatments. Evidence will be summarized in this review for each of these modalities, by describing (1) the methods, (2) the clinical evidence in context of NE both before and with hypothermia, and (3) the research and future directions.

Biofluid Biomarkers in Traumatic Brain Injury: A Systematic Scoping Review

Emerging evidence suggests that biofluid-based biomarkers have diagnostic and prognostic potential in traumatic brain injuries (TBI). However, owing to the lack of a conceptual framework or comprehensive review, it is difficult to visualize the breadth of materials that might be available. We conducted a systematic scoping review to map and categorize the evidence regarding biofluid-based biochemical markers of TBI. A comprehensive search was undertaken in January 2019. Of 25,354 records identified through the literature search, 1036 original human studies were included. Five hundred forty biofluid biomarkers were extracted from included studies and classified into 19 distinct categories. Three categories of biomarkers including cytokines, coagulation tests, and nerve tissue proteins were investigated more than others and assessed in almost half of the studies (560, 515, and 502 from 1036 studies, respectively). S100 beta as the most common biomarker for TBI was tested in 21.2% of studies (220 articles). Cortisol was the only biomarker measured in blood, cerebrospinal fluid, urine, and saliva. The most common sampling time was at admission and within 24 h of injury. The included studies focused mainly on biomarkers from blood and central nervous system sources, the adult population, and severe and blunt injuries. The most common outcome measures used in studies were changes in biomarker concentration level, Glasgow coma scale, Glasgow outcome scale, brain computed tomography scan, and mortality rate. Biofluid biomarkers could be clinically helpful in the diagnosis and prognosis of TBI. However, there was no single definitive biomarker with accurate characteristics. The present categorization would be a road map to investigate the biomarkers of the brain injury cascade separately and detect the most representative biomarker of each category. Also, this comprehensive categorization could provide a guiding framework to design combined panels of multiple biomarkers.

The Current State of Traumatic Brain Injury Biomarker Measurement Methods

Traumatic brain injury (TBI) is associated with high rates of morbidity and mortality partially due to the limited tools available for diagnosis and classification. Measuring panels of protein biomarkers released into the bloodstream after injury has been proposed to diagnose TBI, inform treatment decisions, and monitor the progression of the injury. Being able to measure these protein biomarkers at the point-of-care would enable assessment of TBIs from the point-of-injury to the patient's hospital bedside. In this review, we provide a detailed discussion of devices reported in the academic literature and available on the market that have been designed to measure TBI protein biomarkers in various biofluids and contexts. We also assess the challenges associated with TBI biomarker measurement devices and suggest future research directions to encourage translation of these devices to clinical use.

Myelin basic protein and neurofilament H in postmortem cerebrospinal fluid as surrogate markers of fatal traumatic brain injury

The aim of this study was to investigate if the biomarkers myelin basic protein (MBP) and neurofilament-H (NF-H) yielded informative value in forensic diagnostics when examining cadaveric cerebrospinal fluid (CSF) biochemically via an enzyme-linked immunosorbent assay (ELISA) and comparing the corresponding brain tissue in fatal traumatic brain injury (TBI) autopsy cases by immunocytochemistry versus immunohistochemistry. In 21 trauma and 19 control cases, CSF was collected semi-sterile after suboccipital puncture and brain specimens after preparation. The CSF MBP (p = 0.006) and NF-H (p = 0.0002) levels after TBI were significantly higher than those in cardiovascular controls. Immunohistochemical staining against MBP and against NF-H was performed on cortical and subcortical samples from also biochemically investigated cases (5 TBI cases/5 controls). Compared to the controls, the TBI cases showed a visually reduced staining reaction against MBP or repeatedly ruptured neurofilaments against NF-H. Immunocytochemical tests showed MBP-positive phagocytizing macrophages in CSF with a survival time of > 24 h. In addition, numerous TMEM119-positive microglia could be detected with different degrees of staining intensity in the CSF of trauma cases. As a result, we were able to document that elevated levels of MBP and NF-H in the CSF should be considered as useful neuroinjury biomarkers of traumatic brain injury.

Electrochemical sensing of blood proteins for mild traumatic brain injury (mTBI) diagnostics and prognostics: towards a point-of-care application

Traumatic Brain Injury (TBI) being one of the principal causes of death and acquired disability in the world imposes a large burden on the global economy. Mild TBI (mTBI) is particularly challenging to assess due to the frequent lack of well-pronounced post-injury symptoms. However, if left untreated mTBI (especially when repetitive) can lead to serious long-term implications such as cognitive and neuropathological disorders. Computer tomography and magnetic resonance imaging commonly used for TBI diagnostics require well-trained personnel, are costly, difficult to adapt for on-site measurements and are not always reliable in identifying small brain lesions. Thus, there is an increasing demand for sensitive point-of-care (POC) testing tools in order to aid mTBI diagnostics and prediction of long-term effects. Biomarker quantification in body fluids is a promising basis for POC measurements, even though establishing a clinically relevant mTBI biomarker panel remains a challenge. Actually, a minimally invasive, rapid and reliable multianalyte detection device would allow the efficient determination of injury biomarker release kinetics and thus support the preclinical evaluation and clinical validation of a proposed biomarker panel for future decentralized in vitro diagnostics. In this respect electrochemical biosensors have recently attracted great attention and the present article provides a critical study on the electrochemical protocols suggested in the literature for detection of mTBI-relevant protein biomarkers. The authors give an overview of the analytical approaches for transduction element functionalization, review recent technological advances and highlight the key challenges remaining in view of an eventual integration of the proposed concepts into POC diagnostic solutions.

Challenges of Prevention for a Sustainable Personalized Medicine

The development and implementation of the approaches of personalized medicine for disease prevention are still at infancy, although preventive activities in healthcare represent a key pillar to guarantee health system sustainability. There is an increasing interest in finding informative markers that indicate the disease risk before the manifestation of the disease (primary prevention) or for early disease detection (secondary prevention). Recently, the systematic collection and study of clinical phenotypes and biomarkers consented to the advance of Rehabilomics in tertiary prevention. It consents to identify relevant molecular and physiological factors that can be linked to plasticity, treatment response, and natural recovery. Implementation of these approaches would open avenues to identify people at high risk and enable new preventive lifestyle interventions or early treatments targeted to their individual genomic profile, personalizing prevention and rehabilitation. The integration of personalized medicine into prevention may benefit citizens, patients, healthcare professionals, healthcare authorities, and industry, and ultimately will seek to contribute to better health and quality of life for Europe’s citizens.

Metabolomics in postmortem cerebrospinal fluid diagnostics: a state-of-the-art method to interpret central nervous system-related pathological processes

In the last few years, quantitative analysis of metabolites in body fluids using LC/MS has become an established method in laboratory medicine and toxicology. By preparing metabolite profiles in biological specimens, we are able to understand pathophysiological mechanisms at the biochemical and thus the functional level. An innovative investigative method, which has not yet been used widely in the forensic context, is to use the clinical application of metabolomics. In a metabolomic analysis of 41 samples of postmortem cerebrospinal fluid (CSF) samples divided into cohorts of four different causes of death, namely, cardiovascular fatalities, isoIated torso trauma, traumatic brain injury, and multi-organ failure, we were able to identify relevant differences in the metabolite profile between these individual groups. According to this preliminary assessment, we assume that information on biochemical processes is not gained by differences in the concentration of individual metabolites in CSF, but by a combination of differently distributed metabolites forming the perspective of a new generation of biomarkers for diagnosing (fatal) TBI and associated neuropathological changes in the CNS using CSF samples.

TMEM119 as a specific marker of microglia reaction in traumatic brain injury in postmortem examination

The aim of the present study was a refined analysis of neuroinflammation including TMEM119 as a useful microglia-specific marker in forensic assessments of traumatic causes of death, e.g., traumatic brain injury (TBI). Human brain tissue samples were obtained from autopsies and divided into cases with lethal TBI (n = 25) and subdivided into three groups according to their trauma survival time and compared with an age-, gender-, and postmortem interval-matched cohort of sudden cardiovascular fatalities as controls (n = 23). Brain tissue samples next to cortex contusions and surrounding white matter as well as samples of the ipsilateral uninjured brain stem and cerebellum were collected and stained immunohistochemically with antibodies against TMEM119, CD206, and CCR2. We could document the highest number of TMEM119-positive cells in acute TBI death with highly significant differences to the control numbers. CCR2-positive monocytes showed a significantly higher cell count in the cortex samples of TBI cases than in the controls with an increasing number of immunopositive cells over time. The number of CD206-positive M2 microglial cells increased survival time-dependent. After 3 days of survival, the cell number increased significantly in all four regions investigated compared with controls. In sum, we validate a specific and robustly expressed as well as fast reacting microglia marker, TMEM119, which distinguishes microglia from resident and infiltrating macrophages and thus offers a great potential for the estimation of the minimum survival time after TBI.

B-Type Natriuretic Peptide as a Significant Brain Biomarker for Stroke Triaging Using a Bedside Point-of-Care Monitoring Biosensor

Stroke is a widespread condition that causes 7 million deaths globally. Survivors suffer from a range of disabilities that affect their everyday life. It is a complex condition and there is a need to monitor the different signals that are associated with it. Stroke patients need to be rapidly diagnosed in the emergency department in order to allow the admission of the time-limited treatment of tissue plasminogen activator (tPA). Stroke diagnostics show the use of sophisticated technologies; however, they still contain limitations. The hidden information and technological advancements behind the utilization of biomarkers for stroke triaging are significant. Stroke biomarkers can revolutionize the way stroke patients are diagnosed, monitored, and how they recover. Different biomarkers indicate different cascades and exhibit unique expression patterns which are connected to certain pathologies in the human body. Over the past decades, B-type natriuretic peptide (BNP) and its derivative N-terminal fragment (NT-proBNP) have been increasingly investigated and highlighted as significant cardiovascular biomarkers. This work reviews the recent studies that have reported on the usefulness of BNP and NT-proBNP for stroke triaging. Their classification association is also presented, with increased mortality in stroke, correlation with cardioembolic stroke, and an indication of a second stroke recurrence. Moreover, recent scientific efforts conducted for the technological advancement of a bedside point-of-care (POC) device for BNP and NT-proBNP measurements are discussed. The conclusions presented in this review may hopefully assist in the major efforts that are currently being conducted in order to improve the care of stroke patients.

Serum Concentrations of Neuron-Specific Enolase in Dogs Following Traumatic Brain Injury

The ability to make an accurate prognosis, which is a prerequisite for treatment decisions, is very limited in dogs with traumatic brain injury (TBI). To determine whether serum concentrations of neuron-specific enolase (NSE) have prognostic value in dogs following TBI, we conducted a prospective, observational, controlled clinical study in an intensive care unit of a university teaching hospital. The study population comprised 24 dogs admitted to the hospital within 72 h of a known event of TBI between January 2010 and January 2015, as well as 25 control healthy shelter dogs admitted for elective neutering. Seventeen injured dogs (70%) survived to discharge, four were euthanized and three died within 48 h. Serum samples were obtained from all dogs (in injured dogs, within 72 h of TBI) and NSE concentrations were measured using enzyme-linked immonosorbent assay. Associations between NSE levels and outcome, Modified Glasgow Coma Scale, time to sampling, age or haemolysis scale were determined. Mean serum NSE concentrations were decreased in dogs with TBI compared with healthy controls (19.4 ± 4.14 ng/ml vs. 24.9 ± 4.6 ng/ml, P <0.001). No association was found between serum NSE concentrations and either survival or severity of neurological impairment. A negative correlation was found between serum NSE concentrations and time from trauma to blood collection (r = -0.50, P = 0.022). These results indicate that serum NSE concentration in dogs following TBI is not an effective marker for severity or outcome. Further studies are warranted to standardize serum NSE measurements in dogs and to determine the peak and half-life levels of this potential biomarker.

TMT-based proteomics analysis reveals the protective effects of Xuefu Zhuyu decoction in a rat model of traumatic brain injury

ETHNOPHARMACOLOGICAL RELEVANCE

Xuefu Zhuyu decoction (XFZYD) is a traditional Chinese herbal prescription. It is effective in treating traumatic brain injury (TBI). However, the underlying molecular mechanisms remain unclear.

AIM OF THE STUDY

This study aimed to reveal the possible mechanisms of XFZYD in treating acute TBI through proteomics clues.

MATERIALS AND METHODS

Controlled Cortical Impact (CCI) rats were given gavage administration of XFZYD (9 g/kg/d) or distilled water (equal volume) for three days. The Modified Neurological Severity Score (mNSS), brain water content, HE staining, Nissl staining and immunohistochemistry were performed to assess the effects of XFZYD for TBI treatment. Additionally, tandem mass tag-based (TMT) quantitative proteomics technology was applied to detect proteins of brain cortex. Bioinformatics analysis including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and Protein-protein interaction (PPI) networks were used to analyze differentially expressed proteins (DEPs). Bioinformatics Analysis Tool for Molecular mechanism of TCM (BATMAN-TCM) was conducted to anchor diseases and pathways. Besides, western blotting and immunofluorescence were exerted to verify related proteins.

RESULTS

XFZYD improved neurologic functions, reduced encephaledema and ameliorated cell morphology around the injured area in CCI rats. A total of 6099 proteins were identified with false discovery rate (FDR) < 1%. Overlapping DEPs (105 DEPs) were identified (295 DEPs and 804 DEPs in CCI/Sham or XFZYD/CCI group, respectively). Of these DEPs, 17 were regulated by XFZYD. Bioinformatics analysis showed that the 17 DEPs were predominantly related to platelet activation and PI3K-Akt signaling pathway. Next, PLG and CD34 were verified with molecular biotechnology.

CONCLUSIONS

XFZYD exerts therapeutic effects through multi-pathways regulation in the treatment of TBI. This work may provide proteomics clues for the continuation of research on TBI treatment with XFZYD.

Assessment of Long-Term Effects of Sports-Related Concussions: Biological Mechanisms and Exosomal Biomarkers

Concussion or mild traumatic brain injury (mTBI) in athletes can cause persistent symptoms, known as post-concussion syndrome (PCS), and repeated injuries may increase the long-term risk for an athlete to develop neurodegenerative diseases such as chronic traumatic encephalopathy (CTE), and Alzheimer's disease (AD). The Center for Disease Control estimates that up to 3.8 million sport-related mTBI are reported each year in the United States. Despite the magnitude of the phenomenon, there is a current lack of comprehensive prognostic indicators and research has shown that available monitoring tools are moderately sensitive to short-term concussion effects but less sensitive to long-term consequences. The overall aim of this review is to discuss novel, quantitative, and objective measurements that can predict long-term outcomes following repeated sports-related mTBIs. The specific objectives were (1) to provide an overview of the current clinical and biomechanical tools available to health practitioners to ensure recovery after mTBIs, (2) to synthesize potential biological mechanisms in animal models underlying the long-term adverse consequences of mTBIs, (3) to discuss the possible link between repeated mTBI and neurodegenerative diseases, and (4) to discuss the current knowledge about fluid biomarkers for mTBIs with a focus on novel exosomal biomarkers. The conclusions from this review are that current post-concussion clinical tests are not sufficiently sensitive to injury and do not accurately quantify post-concussion alterations associated with repeated mTBIs. In the current review, it is proposed that current practices should be amended to include a repeated symptom inventory, a cognitive assessment of executive function and impulse control, an instrumented assessment of balance, vestibulo-ocular assessments, and an improved panel of blood or exosome biomarkers.

White matter injury and neurodevelopmental disabilities: A cross-disease (dis)connection

White matter (WM) injury, once known primarily in preterm newborns, is emerging in its non-focal (diffused), non-necrotic form as a critical component of subtle brain injuries in many early-life diseases like prematurity, intrauterine growth restriction, congenital heart defects, and hypoxic-ischemic encephalopathy. While advances in medical techniques have reduced the number of severe outcomes, the incidence of tardive impairments in complex cognitive functions or psychopathology remains high, with lifelong detrimental effects. The importance of WM in coordinating neuronal assemblies firing and neural groups synchronizing within multiple frequency bands through myelination, even mild alterations in WM structure, may interfere with the cognitive performance that increasing social and learning demands would exploit tardively during children growth. This phenomenon may contribute to explaining longitudinally the high incidence of late-appearing impairments that affect children with a history of perinatal insults. Furthermore, WM abnormalities have been highlighted in several neuropsychiatric disorders, such as autism and schizophrenia. In this review, we gather and organize evidence on how diffused WM injuries contribute to neurodevelopmental disorders through different perinatal diseases and insults. An insight into a possible common, cross-disease, mechanism, neuroimaging and monitoring, biomarkers, and neuroprotective strategies will also be presented.

Effect of dexmedetomidine on brain function and hemodynamics in patients undergoing lung cancer resection

Effect of dexmedetomidine on the brain function and hemodynamics in patients undergoing lung cancer resection were explored. Eighty-seven patients with lung cancer undergoing lung cancer resection in Weifang People's Hospital from January 2014 to June 2018 were enrolled in this study. Patients conventionally anesthetized by propofol, midazolam, sufentanil, or cisatracurium besilate (41 cases) were assigned to the control group and those anesthetized by conventional anesthetic and dexmedetomidine (46 cases) were assigned to the research group. The hemodynamic parameters, neuron-specific enolase (NSE), and astrocyte S-100p protein (S-100β) were compared between the two groups before induction (T0), 5 min after induction (T1), at the end of surgery (T2), time of extubation (T3), and 5 min after extubation (T4). The cognitive function of patients was graded by the mini-mental state examination (MMSE) after patients recovered from anesthesia. In both the control group and the research group, the levels of mean arterial pressure (MAP), heart rate (HR), and central venous pressure (CVP). were statistically higher at T2 and T3 than those at T0 (all P<0.05). The levels of MAP, HR, and CVP were statistically lower in the research group than those in the control group at T2 and T3 (P<0.05). The levels of serum NSE and S100β protein in the research group and the control group increased at T2, T3, and T4, the control group was higher than the research group at each time point, and the difference was statistically significant (P<0.05). Comparison of the MMSE score and the total case number of adverse reactions between the two groups showed no statistical difference (both P>0.05). The MMSE score was positively correlated with the serum levels of NSE and S100β in the two groups (r-values were 0.661 and 0.585, P<0.05). Dexmedetomidine can effectively protect patients' perioperative brain function with small impacts on perioperative hemodynamics, so it is worthy of clinical application.

Prognostic Value of Glial Fibrillary Acidic Protein in Patients With Moderate and Severe Traumatic Brain Injury: A Systematic Review and Meta-Analysis

OBJECTIVES

Biomarkers have been suggested as potential prognostic predictors following a moderate or severe traumatic brain injury but their prognostic accuracy is still uncertain. The objective of this systematic review is to assess the ability of the glial fibrillary acidic protein to predict prognosis in patients with moderate or severe traumatic brain injury.

DATA SOURCES

MEDLINE, Embase, CENTRAL, and BIOSIS electronic databases and conference abstracts, bibliographies of selected studies, and narrative reviews were searched.

STUDY SELECTION

Pairs of reviewers identified eligible studies. Cohort studies including greater than or equal to four patients with moderate or severe traumatic brain injury and reporting glial fibrillary acidic protein levels according to the outcomes of interest, namely Glasgow Outcome Scale or Extended Glasgow Outcome Scale, and mortality, were eligible.

DATA EXTRACTION

Pairs of reviewers independently extracted data from the selected studies using a standardized case report form. Mean levels were log-transformed, and their differences were pooled with random effect models. Results are presented as geometric mean ratios. Methodologic quality, risk of bias, and applicability concerns of the included studies were assessed.

DATA SYNTHESIS

Seven-thousand seven-hundred sixty-five citations were retrieved of which 15 studies were included in the systematic review (n = 1,070), and nine were included in the meta-analysis (n = 701). We found significant associations between glial fibrillary acidic protein serum levels and Glasgow Outcome Scale score less than or equal to 3 or Extended Glasgow Outcome Scale score less than or equal to 4 (six studies: geometric mean ratio 4.98 [95% CI, 2.19-11.13]; I = 94%) and between mortality (seven studies: geometric mean ratio 8.13 [95% CI, 3.89-17.00]; I = 99%).

CONCLUSIONS

Serum glial fibrillary acidic protein levels were significantly higher in patients with an unfavorable prognosis. Glial fibrillary acidic protein has a potential for clinical bedside use in helping for prognostic assessment. Further research should focus on multimodal approaches including tissue biomarkers for prognostic evaluation in critically ill patients with traumatic brain injury.

Metabolomics and Biomarker Discovery in Traumatic Brain Injury

Traumatic brain injury (TBI) is one of the leading causes of disability and mortality worldwide. The TBI pathogenesis can induce broad pathophysiological consequences and clinical outcomes attributed to the complexity of the brain. Thus, the diagnosis and prognosis are important issues for the management of mild, moderate, and severe forms of TBI. Metabolomics of readily accessible biofluids is a promising tool for establishing more useful and reliable biomarkers of TBI than using clinical findings alone. Metabolites are an integral part of all biochemical and pathophysiological pathways. Metabolomic processes respond to the internal and external stimuli resulting in an alteration of metabolite concentrations. Current high-throughput and highly sensitive analytical tools are capable of detecting and quantifying small concentrations of metabolites, allowing one to measure metabolite alterations after a pathological event when compared to a normal state or a different pathological process. Further, these metabolic biomarkers could be used for the assessment of injury severity, discovery of mechanisms of injury, and defining structural damage in the brain in TBI. Metabolic biomarkers can also be used for the prediction of outcome, monitoring treatment response, in the assessment of or prognosis of post-injury recovery, and potentially in the use of neuroplasticity procedures. Metabolomics can also enhance our understanding of the pathophysiological mechanisms of TBI, both in primary and secondary injury. Thus, this review presents the promising application of metabolomics for the assessment of TBI as a stand-alone platform or in association with proteomics in the clinical setting.

Brain-Specific Serum Biomarkers Predict Neurological Morbidity in Diagnostically Diverse Pediatric Intensive Care Unit Patients

BACKGROUND

Unexpected neurological morbidity in Pediatric Intensive Care Units (PICUs) remains high and is difficult to detect proactively. Brain-specific biomarkers represent a novel approach for early detection of neurological injury. We sought to determine whether serum concentrations of neuron-specific enolase (NSE), myelin basic protein (MBP), and S100B, specific for neurons, oligodendrocytes, and glia, respectively, were predictive of neurological morbidity in critically ill children.

METHODS

Serum was prospectively collected on days 1-7 from diagnostically diverse PICU patients (n = 103). Unfavorable neurological outcome at hospital discharge was defined as Pediatric Cerebral Performance Category (PCPC) score of 3-6 with a deterioration from baseline. NSE, MBP, and S100B concentrations were measured by enzyme-linked immunosorbent assay.

RESULTS

Peak biomarker levels were greater in patients with unfavorable versus favorable neurological outcome [NSE 39.4 ± 44.1 vs. 12.2 ± 22.9 ng/ml (P = 0.005), MBP 9.1 ± 11.5 vs. 0.6 ± 1.3 ng/ml (P = 0.003), S100B 130 ± 232 vs. 34 ± 70 pg/ml (P = 0.04), respectively; mean ± SD]. Peak levels were each independently associated with unfavorable neurological outcome when controlling for presence of primary neurologic admission diagnosis and poor baseline PCPC using logistic regression analysis (NSE, P = 0.04; MBP, P = 0.004; S100B, P = 0.04), and had the following receiver operating characteristics: NSE 0.75 (0.58, 0.92), MBP 0.81 (0.66, 0.94), and S100B 0.80 (0.67, 0.93) (area under the curve [95% confidence intervals]).

CONCLUSIONS

Prospectively collected brain-specific serum biomarkers predict unfavorable neurological outcome in critically ill children. Serum biomarkers used in conjunction with clinical data could be used to generate models predicting early detection of neurological injury, allowing for more timely diagnostic and therapeutic interventions, potentially reducing neurological morbidity in the PICU.

Toward development of clinically translatable diagnostic and prognostic metrics of traumatic brain injury using animal models: A review and a look forward

Traumatic brain injury is a leading cause of cognitive and behavioral deficits in children in the US each year. There is an increasing interest in both clinical and pre-clinical studies to discover biomarkers to accurately diagnose traumatic brain injury (TBI), predict its outcomes, and monitor its progression especially in the developing brain. In humans, the heterogeneity of TBI in terms of clinical presentation, injury causation, and mechanism has contributed to the many challenges associated with finding unifying diagnosis, treatment, and management practices. In addition, findings from adult human research may have little application to pediatric TBI, as age and maturation levels affect the injury biomechanics and neurophysiological consequences of injury. Animal models of TBI are vital to address the variability and heterogeneity of TBI seen in human by isolating the causation and mechanism of injury in reproducible manner. However, a gap between the pre-clinical findings and clinical applications remains in TBI research today. To take a step toward bridging this gap, we reviewed several potential TBI tools such as biofluid biomarkers, electroencephalography (EEG), actigraphy, eye responses, and balance that have been explored in both clinical and pre-clinical studies and have shown potential diagnostic, prognostic, or monitoring utility for TBI. Each of these tools measures specific deficits following TBI, is easily accessible, non/minimally invasive, and is potentially highly translatable between animals and human outcomes because they involve effort-independent and non-verbal tasks. Especially conspicuous is the fact that these biomarkers and techniques can be tailored for infants and toddlers. However, translation of preclinical outcomes to clinical applications of these tools necessitates addressing several challenges. Among the challenges are the heterogeneity of clinical TBI, age dependency of some of the biomarkers, different brain structure, life span, and possible variation between temporal profiles of biomarkers in human and animals. Conducting parallel clinical and pre-clinical research, in addition to the integration of findings across species from several pre-clinical models to generate a spectrum of TBI mechanisms and severities is a path toward overcoming some of these challenges. This effort is possible through large scale collaborative research and data sharing across multiple centers. In addition, TBI causes dynamic deficits in multiple domains, and thus, a panel of biomarkers combining these measures to consider different deficits is more promising than a single biomarker for TBI. In this review, each of these tools are presented along with the clinical and pre-clinical findings, advantages, challenges and prospects of translating the pre-clinical knowledge into the human clinical setting.

Why Does Brain Trauma Research Fail?

Traumatic brain injury (TBI) represents a major health care problem and a significant social and economic issue worldwide. Considering the generalized failure in introducing effective drugs and clinical protocols, there is an urgent need for efficient treatment modalities, able to improve devastating posttraumatic morbidity and mortality. In this work, the status of brain trauma research is analyzed in all its aspects, including basic and translational science and clinical trials. Implicit and explicit challenges to different lines of research are discussed and clinical trial structures and outcomes are scrutinized, along with possible explanations for systematic therapeutic failures and their implications for future development of drug and clinical trials. Despite significant advances in basic and clinical research in recent years, no specific therapeutic protocols for TBI have been shown to be effective. New potential therapeutic targets have been identified, following a better understanding of pathophysiologic mechanisms underlying TBI, although with disappointing results. Several reasons can be pinpointed at different levels, from inaccurate animal models of disease to faulty preclinical and clinical trials, with poor design and subjective outcome measures. Distinct strategies can be delineated to overcome specific shortcomings of research studies. Identifying and contextualizing the failures that have dominated TBI research is mandatory. This review analyzes current approaches and discusses possible strategies for improving outcomes.

Pathophysiology of Concussion

Although concussion has been a subject of interest for centuries, this condition remains poorly understood. The mechanistic underpinnings and accepted definition of concussion remain elusive. To make sense of these issues, this article presents a brief history of concussion studies, detailing the evolution of motivations and experimental conclusions over time. Interest in concussion as a subject of scientific inquiry has increased with growing concern about the long-term consequences of mild traumatic brain injury (TBI). Although concussion is often associated with mild TBI, these conditions-the former a neurological syndrome, the latter a neurological event-are distinct, both mechanistically and pathobiologically. Modern research primarily focuses on the study of the biomechanics, pathophysiology, potential biomarkers and neuroimaging to distinguish concussion from mild TBI. In addition, mild TBI and concussion outcomes are influenced by age, sex, and genetic differences in people. With converging experimental objectives and methodologies, future concussion research has the potential to improve clinical assessment, treatment, and preventative measures.

Point-of-Care Surface Plasmon Resonance Biosensor for Stroke Biomarkers NT-proBNP and S100β Using a Functionalized Gold Chip with Specific Antibody

Surface-plasmon-resonance (SPR) is a quantum-electromagnetic phenomenon arising from the interaction of light with free electrons at a metal-dielectric interface. At a specific angle/wavelength of light, the photon's energy is transferred to excite the oscillation of the free electrons on the surface. A change in the refractive-index (RI) may occur, which is influenced by the analyte concentration in the medium in close contact with the metal surface. SPR has been widely used for the detection of gaseous, liquid, or solid samples. In this study, a functionalized specific SPR chip was designed and used in a novel point-of-care SPR module (PhotonicSys SPR H5) for the detection of the stroke biomarkers NT-proBNP and S100β. These biomarkers have proven to be good for stroke diagnosis, with sensitivity and specificity of >85%. Specific detection was done by binding a biomolecular-recognizing antibody onto the Au SPR-chip. Detection was tested in water and plasma samples. NT-proBNP and S100β were detected in a range of concentrations for stroke, from 0.1 ng/mL to 10 ng/mL. The RI of the blank plasma samples was 1.362412, and the lowest concentration tested for both biomarkers showed a prominent shift in the RI signal (0.25 ng/mL NT-proBNP (1.364215) and S100β (1.364024)). The sensor demonstrated a clinically relevant limit-of-detection of less than ng/mL.

Tau protein as a diagnostic marker for diffuse axonal injury

Background

Diffuse axonal injury (DAI) is difficult to identify in the early phase of traumatic brain injury (TBI) using common diagnostic methods. Tau protein is localized specifically in nerve axons. We hypothesized that serum level of tau can be a useful biomarker to diagnose DAI in the early phase of TBI.

Methods & results

We measured serum tau levels in 40 TBI patients who were suspected of DAI within 6 hours after TBI to evaluate the accuracy of the tau level as a diagnostic marker for DAI. Diagnosis of DAI was confirmed according to magnetic resonance imaging (MRI) findings. The serum tau level in the DAI group (n = 13) was significantly higher than that in the non-DAI group (n = 27) (DAI vs. non-DAI, 25.3 [0 to 99.1] pg/mL vs. 0 [0 to 44.4] pg/mL, P = 0.03)). A receiver-operating characteristic curve to evaluate the diagnostic ability of serum tau level within 6 hours for DAI showed an area under the curve of 0.690 with 74.1% for sensitivity and 69.2% for specificity. Serum tau level was not significantly higher in unfavorable outcome group (Glasgow Outcome scale [GOS] score = 1–3 at hospital discharge) compared with favorable outcome group (GOS score = 4–5) (P = 0.19).

Conclusions

Tau protein may be a useful biomarker for diagnosis of DAI in the early phase of TBI.

Cerebral Alterations Following Experimental Multiple Trauma and Hemorrhagic Shock

Multiple trauma (MT) associated with hemorrhagic shock (HS) might lead to cerebral hypoperfusion and brain damage. We investigated cerebral alterations using a new porcine MT/HS model without traumatic brain injury (TBI) and assessed the neuroprotective properties of mild therapeutic hypothermia. Male pigs underwent standardized MT with HS (45% or 50% loss of blood volume) and resuscitation after 90/120 min (T90/T120). In additional groups (TH90/TH120) mild hypothermia (33°C) was induced following resuscitation. Normothermic or hypothermic sham animals served as controls. Intracranial pressure, cerebral perfusion pressure (CPP), and cerebral oxygenation (PtiO2) were recorded up to 48.5 h. Serum protein S-100B and neuron-specific enolase (NSE) were measured by ELISA. Cerebral inflammation was quantified on hematoxylin and eosin -stained brain slices; Iba1, S100, and inducible nitric oxide synthase (iNOS) expression was assessed using immunohistochemistry. Directly after MT/HS, CPP and PtiO2 were significantly lower in T90/T120 groups compared with sham. After resuscitation both parameters showed a gradual recovery. Serum protein S-100B and NSE increased temporarily as a result of MT/HS in T90 and T90/T120 groups, respectively. Cerebral inflammation was found in all groups. Iba1-staining showed significant microgliosis in T90 and T120 animals. iNOS-staining indicated a M1 polarization. Mild hypothermia reduced cerebral inflammation in the TH90 group, but resulted in increased iNOS activation. In this porcine long-term model, we did not find evidence of gross cerebral damage when resuscitation was initiated within 120 min after MT/HS without TBI. However, trauma-related microglia activation and M1 microglia polarization might be a consequence of temporary hypoxia/ischemia and further research is warranted to detail underlying mechanisms. Interestingly, mild hypothermia did not exhibit neuroprotective properties when initiated in a delayed fashion.

Use of neuron-specific enolase to predict mild brain injury in motorcycle crash patients with maxillofacial fractures: A pilot study

PURPOSE

Mild traumatic brain injury (TBI) is common but accurate diagnosis and its clinical consequences have been a problem. Maxillofacial trauma does have an association with TBI. Neuron-specific enolase (NSE) has been developed to evaluate neuronal damage. The objective of this study was to investigate the accuracy of NSE serum levels to detect mild brain injury of patients with sustained maxillofacial fractures during motor vehicle accidents.

METHODS

Blood samples were drawn from 40 healthy people (control group) and 48 trauma patients who had sustained isolated maxillofacial fractures and mild brain injury in motor vehicle accidents. Brain injuries were graded by Glasgow Coma Scale. In the trauma group, correlations between the NSE serum value and different facial fracture sites were also assessed.

RESULTS

The NSE serum level (mean ± SD, ng/ml) in the 48 patients with maxillofacial fractures and mild TBI was 13.12 ± 9.68, significantly higher than that measured in the healthy control group (7.72 ± 1.82, p < 0.001). The mean NSE serum level (ng/ml) in the lower part of the facial skeleton (15.44 with SD 15.34) was higher than that in the upper facial part (12.42 with SD 7.68); and the mean NSE level (ng/ml) in the middle-and lower part (11.97 with SD 5.63) was higher than in the middle part (7.88 with SD 2.64).

CONCLUSION

An increase in NSE serum levels can be observed in patients sustained maxillofacial fractures and mild brain injury.

Emergent Prophylactic, Reparative and Restorative Brain Interventions for Infants Born Preterm With Cerebral Palsy

Worldwide, an estimated 15 million babies are born preterm (<37 weeks' gestation) every year. Despite significant improvements in survival rates, preterm infants often face a lifetime of neurodevelopmental disability including cognitive, behavioral, and motor impairments. Indeed, prematurity remains the largest risk factor for the development of cerebral palsy. The developing brain of the preterm infant is particularly fragile; preterm babies exhibit varying severities of cerebral palsy arising from reductions in both cerebral white and gray matter volumes, as well as altered brain microstructure and connectivity. Current intensive care therapies aim to optimize cardiovascular and respiratory function to protect the brain from injury by preserving oxygenation and blood flow. If a brain injury does occur, definitive diagnosis of cerebral palsy in the first few hours and weeks of life is difficult, especially when the lesions are subtle and not apparent on cranial ultrasound. However, early diagnosis of mildly affected infants is critical, because these are the patients most likely to respond to emergent treatments inducing neuroplasticity via high-intensity motor training programs and regenerative therapies involving stem cells. A current controversy is whether to test universal treatment in all infants at risk of brain injury, accepting that some patients never required treatment, because the perceived potential benefits outweigh the risk of harm. Versus, waiting for a diagnosis before commencing targeted treatment for infants with a brain injury, and potentially missing the therapeutic window. In this review, we discuss the emerging prophylactic, reparative, and restorative brain interventions for infants born preterm, who are at high risk of developing cerebral palsy. We examine the current evidence, considering the timing of the intervention with relation to the proposed mechanism/s of action. Finally, we consider the development of novel markers of preterm brain injury, which will undoubtedly lead to improved diagnostic and prognostic capability, and more accurate instruments to assess the efficacy of emerging interventions for this most vulnerable group of infants.

Enduring Neuroprotective Effect of Subacute Neural Stem Cell Transplantation After Penetrating TBI

Traumatic brain injury (TBI) is the largest cause of death and disability of persons under 45 years old, worldwide. Independent of the distribution, outcomes such as disability are associated with huge societal costs. The heterogeneity of TBI and its complicated biological response have helped clarify the limitations of current pharmacological approaches to TBI management. Five decades of effort have made some strides in reducing TBI mortality but little progress has been made to mitigate TBI-induced disability. Lessons learned from the failure of numerous randomized clinical trials and the inability to scale up results from single center clinical trials with neuroprotective agents led to the formation of organizations such as the Neurological Emergencies Treatment Trials (NETT) Network, and international collaborative comparative effectiveness research (CER) to re-orient TBI clinical research. With initiatives such as TRACK-TBI, generating rich and comprehensive human datasets with demographic, clinical, genomic, proteomic, imaging, and detailed outcome data across multiple time points has become the focus of the field in the United States (US). In addition, government institutions such as the US Department of Defense are investing in groups such as Operation Brain Trauma Therapy (OBTT), a multicenter, pre-clinical drug-screening consortium to address the barriers in translation. The consensus from such efforts including “The Lancet Neurology Commission” and current literature is that unmitigated cell death processes, incomplete debris clearance, aberrant neurotoxic immune, and glia cell response induce progressive tissue loss and spatiotemporal magnification of primary TBI. Our analysis suggests that the focus of neuroprotection research needs to shift from protecting dying and injured neurons at acute time points to modulating the aberrant glial response in sub-acute and chronic time points. One unexpected agent with neuroprotective properties that shows promise is transplantation of neural stem cells. In this review we present (i) a short survey of TBI epidemiology and summary of current care, (ii) findings of past neuroprotective clinical trials and possible reasons for failure based upon insights from human and preclinical TBI pathophysiology studies, including our group's inflammation-centered approach, (iii) the unmet need of TBI and unproven treatments and lastly, (iv) present evidence to support the rationale for sub-acute neural stem cell therapy to mediate enduring neuroprotection.