Blood-based biomarkers for prediction of intracranial hemorrhage and outcome in patients with moderate or severe traumatic brain injury

Modeling biomarker kinetics of Aβ levels in serum following blast

Elucidating the unique neuropathological response to blast exposure remains a barrier towards the development of diagnostic approaches for those with blast-induced traumatic brain injury (bTBI). Quantification of biomarker concentrations in the blood post-injury is typically used to inform brain injury severity. However, injury progression and associated changes in biomarker concentrations are sensitive to parameters such as the blast overpressure (BOP) magnitude and frequency of blast exposure. Through this work, a blast-dose biomarker kinetics (BxK) platform was developed and validated for Aβ42 as a promising predictor of injury post-blast. Blast-dose responses accounting for BOP magnitude and frequency were integrated into a mathematical model accounting for whole-body Aβ peptide kinetics. Validation of the developed model was performed through comparison with acute monomer levels in the blood serum of 15 service members exposed to repeated low-level blast while undergoing three-day weapons training. Amyloid precursor protein (APP) synthesis was assumed to be proportional to blast magnitude and additive effects within a window of recovery were applied to account for cumulative exposure. Aβ42 concentrations in the blood serum were predicted within 6.5 ± 5.2% on average, demonstrating model feasibility and biomarker sensitivity to blast. Outcomes discuss how modulation of patient-specific factors (age, weight, genetic factors, years of exposure, sleep) and pathophysiological factors (BBB permeability, amyloidogenic pathology, neuroinflammation) can reveal potential sources of variability in experimental data and be incorporated into the blast-dose BxK platform in future iterations. Advancements in model complexity accounting for sex-specific factors, weapon system, stress levels, risk of symptom onset, and pharmacological treatment strategies are anticipated to improve model calibration. Utilization of this blast-dose BxK model to identify drivers of pathophysiological mechanisms and predict chronic outcomes has the potential to transform bTBI diagnostic, prognostic, and therapeutic strategies.

Beyond Glasgow Coma Scale: Prehospital prediction of traumatic brain injury

INTRODUCTION

Early identification of traumatic brain injury followed by timely, targeted treatment is essential. We aimed to establish the ability of prehospital Glasgow Coma Scale score alone and combined with vital signs to predict hospital-diagnosed traumatic brain injury.

METHODS

This study included adults from the 2017-2020 Trauma Quality Improvement Program data set with blunt mechanism. We calculated test characteristics of prehospital Glasgow Coma Scale score ≤12 alone and Glasgow Coma Scale score combined with heart rate and systolic blood pressure for predicting (1) any traumatic brain injury and (2) moderate to severe traumatic brain injury. Diagnostic performances were calculated in all patients and older adults (≥55 years). We used decision curve analysis to determine the net diagnostic benefit of prehospital Glasgow Coma Scale score combined with heart rate + systolic blood pressure over Glasgow Coma Scale score alone.

RESULTS

Of 1,687,336 patients, 39.1% had any traumatic brain injury, 3.7% had moderate to severe traumatic brain injury, and 9.1% had a prehospital Glasgow Coma Scale score ≤12. Prehospital Glasgow Coma Scale score ≤12 alone had a sensitivity 83.1%, specificity 93.7%, negative predictive value 99.3%, and positive predictive value 33.7% for predicting moderate to severe traumatic brain injury. Adding prehospital heart rate <65/min and systolic blood pressure >150 mm Hg to Glasgow Coma Scale score ≤12 improved the positive predictive value for moderate to severe traumatic brain injury (55.3%), with a preserved negative predictive value of 96.4%. Decision curve analysis showed the traumatic brain injury prediction model including prehospital heart rate and systolic blood pressure had the greatest net benefit across most threshold probabilities.

CONCLUSION

Less than a third of adult blunt trauma patients with a prehospital Glasgow Coma Scale score ≤12 have moderate to severe traumatic brain injury. Supplementing Glasgow Coma Scale score with prehospital vital signs improves diagnostic accuracy, potentially by filtering out patients with altered consciousness due to shock. Future work should better identify patients for traumatic brain injury-specific treatments in prehospital settings, including triage destination.

Prognostic Values of Routine Clinical Tests in Adult Patients with Traumatic Brain Injury

OBJECTIVE

To determine the prognostic impacts of the characteristics in routine plasma and blood tests for patients with traumatic brain injury (TBI).

METHODS

A total of 136 consecutive adult patients with TBI were recruited. Blood and plasma routine tests were performed within 24 hours from admission. All patients were briefly followed up at the third month after discharge. We analyzed the prognostic factors with univariate and multifactor logistic regression models in the patients receiving surgical and conservative treatments, respectively.

RESULTS

We found different prognostic factors in the patients receiving diverse treatments. In the patients receiving surgical treatment, infection is the only influencing factor, while in the patients receiving conservative treatment, age (P = 0.004), white blood cell count (WBC) (P = 0.008), and albumin (P = 0.040) were the independent factors of prognosis. In the receiver operator characteristic analysis, the values of area under the curve of these factors were 0.788 for age, 0.695 for WBC, and 0.709 for albumin, respectively. The combined area under the curve of the 3 factors was 0.898.

CONCLUSIONS

TBI patients receiving diverse treatments might have different pathophysiologic conditions and different influencing factors of prognosis.

Beyond the Hit: The Hidden Costs of Repetitive Head Trauma

Repetitive head trauma in sports, particularly concussions, has been strongly associated with neurocognitive impairments, including depression, chronic traumatic encephalopathy (CTE), and altered brain function. These injuries can have significant consequences on major cognitive processes, such as learning and memory. This review synthesizes research that examines the effects of sports-related head trauma, particularly in football, on cognitive functioning. Post-mortem analyses of players across all positions have revealed neuropathological evidence of CTE, including a distinct reduction in hippocampal volume. Notably, episodic memory, a component of declarative memory, is frequently compromised in individuals with CTE. Furthermore, deficits in working memory may contribute to decreased performance during play. Early detection of head trauma and implementation of preventive strategies are crucial for mitigating long-term consequences. While impact-reducing techniques have shown some efficacy in decreasing brain injury incidence, proper tackling techniques, such as "heads-up play," also play a vital role in minimizing risk. Further research and increased awareness are needed to ensure athletes are fully informed of the potential cognitive risks associated with participation in high-impact sports.

Extracellular cold-inducible RNA-binding protein in CNS injury: molecular insights and therapeutic approaches

Central nervous system (CNS) injuries, such as ischemic stroke (IS), intracerebral hemorrhage (ICH) and traumatic brain injury (TBI), are a significant global burden. The complex pathophysiology of CNS injury is comprised of primary and secondary injury. Inflammatory secondary injury is incited by damage-associated molecular patterns (DAMPs) which signal a variety of resident CNS cells and infiltrating immune cells. Extracellular cold-inducible RNA-binding protein (eCIRP) is a DAMP which acts through multiple immune and non-immune cells to promote inflammation. Despite the well-established role of eCIRP in systemic and sterile inflammation, its role in CNS injury is less elucidated. Recent literature suggests that eCIRP is a pleiotropic inflammatory mediator in CNS injury. eCIRP is also being evaluated as a clinical biomarker to indicate prognosis in CNS injuries. This review provides a broad overview of CNS injury, with a focus on immune-mediated secondary injury and neuroinflammation. We then review what is known about eCIRP in CNS injury, and its known mechanisms in both CNS and non-CNS cells, identifying opportunities for further study. We also explore eCIRP's potential as a prognostic marker of CNS injury severity and outcome. Next, we provide an overview of eCIRP-targeting therapeutics and suggest strategies to develop these agents to ameliorate CNS injury. Finally, we emphasize exploring novel molecular mechanisms, aside from neuroinflammation, by which eCIRP acts as a critical mediator with significant potential as a therapeutic target and prognostic biomarker in CNS injury.

Diagnostic and prognostic performance of urine ubiquitin carboxy-terminal hydrolase L1 across multiple acute brain injury types - A longitudinal prospective cohort study

Introduction

Ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) is recognized as a diagnostic and prognostic blood biomarker for traumatic brain injury (TBI). This study aimed to evaluate whether UCH-L1 concentrations measured in patients' urine post-injury could serve as a diagnostic or prognostic biomarker for outcomes in various types of acute brain injuries (ABI).

Material and methods

This pilot study included 46 ABI patients: aneurysmal subarachnoid hemorrhage (n = 22), ischemic stroke (n = 16), and traumatic brain injury (n = 8), along with three healthy controls. Urine samples were collected at early (1.50 ± 0.70 days) and late (9.17 ± 3.40 days) periods post-admission. UCH-L1 and creatinine levels were quantified using ELISA. UCH-L1 concentrations were compared to functional outcomes (modified Rankin Scale, mRS) and dichotomized into favorable (mRS 0-3) and unfavorable (mRS 4-6) groups. Non-parametric statistical tests and ROC analysis was performed.

Results

UCH-L1 concentrations in healthy controls were significantly lower compared to both early and late samples after ABI (p ≤ 0.001). The diagnostic performance of urine UCH-L1 at early timepoint showed excellent discriminatory ability, with AUC of 97.6% (95% CI: 93.0-100, p = 0.006 (sensitivity 98%, specificity 100%). Urine UCH-L1 concentrations, both with and without creatinine normalization, did not distinguish between favorable and unfavorable outcomes in either early (p = 0.88 and p = 0.36) or late samples (p = 0.98 and p = 0.30) in any types of ABI.

Discussion and conclusions

Although UCH-L1 concentrations in urine did not differentiate between favorable and unfavorable outcomes, a significant difference was observed between healthy subjects and ABI patients. This finding underscores the significant diagnostic utility of urine UCH-L1 concentrations, regardless of the type of acute brain injury.

Evaluation of GFAP/UCH-L1 biomarkers for computed tomography exclusion in mild traumatic brain injury (mTBI)

INTRODUCTION

Mild traumatic brain injury (mTBI) represents a major public health concern and affects millions of people worldwide every year. Diagnosis mainly relies on clinical criteria and computed tomography (CT) scans. GFAP (glial fibrillary acidic protein) and UCH-L1 (ubiquitin carboxyl-terminal hydrolase-L1) have been recently studied as potential biomarkers of mTBI. This study retrospectively evaluated the possible use of these combined biomarkers as negative predictors for excluding brain injuries in patients with suspected mTBI in the emergency department.

METHODS

Adult patients (n = 130) enrolled at Tor Vergata University Hospital (Rome, Italy), consecutively registered at the triage of the emergency department between October 2022 and January 2023, with non-penetrating TBI and Glasgow Coma Scale (GCS) score of 13-15, were considered. All eligible patients underwent intracranial CT scans and blood tests, within 12 h after trauma, for GFAP and UCH-L1 serum concentrations.

RESULTS

Intracranial CT detected injuries in only seven patients (5%); GFAP and UCH-L1 tested positive in 96 patients and negative in 34 patients (74% vs. 26%). Combined biomarkers had a sensitivity equal to 1.00 (95% CI 0.64-1.00) and a negative predictive value (NPV) of 1.00 (0.99-1.00) in mTBI diagnosis with a negative CT.

CONCLUSIONS

Combined laboratory tests for GFAP and UCH-L1 biomarkers might play a potential clinical role in avoiding unnecessary head CT scans after mTBI in emergency departments.

Plasma Inflammation Markers Linked to Complications and Outcomes after Spontaneous Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) could trigger inflammatory responses. However, the specific role of inflammatory proteins in the pathological mechanism, complications, and prognosis of ICH remains unclear. In this study, we investigated the expression of 92 plasma inflammation-related proteins in patients with ICH (n = 55) and healthy controls (n = 20) using an Olink inflammation panel and discussed the relation to the severity of stroke, clinical complications, 30-day mortality, and 90-day outcomes. Our result showed that six proteins were upregulated in ICH patients compared with healthy controls, while seventy-four proteins were downregulated. In patients with ICH, seven proteins were increased in the severe stroke group compared with the moderate stroke group. In terms of complications, two proteins were downregulated in patients with pneumonia, while nine proteins were upregulated in patients with sepsis. Compared with the survival group, three proteins were upregulated, and one protein was downregulated in the death group. Compared with the good outcome group, eight proteins were upregulated, and four proteins were downregulated in the poor outcome group. In summary, an in-depth exploration of the differential inflammatory factors in the early stages of ICH could deepen our understanding of the pathogenesis of ICH, predict patient prognosis, and explore new treatment strategies.

Biomaterials and tissue engineering in traumatic brain injury: novel perspectives on promoting neural regeneration

Traumatic brain injury is a serious medical condition that can be attributed to falls, motor vehicle accidents, sports injuries and acts of violence, causing a series of neural injuries and neuropsychiatric symptoms. However, limited accessibility to the injury sites, complicated histological and anatomical structure, intricate cellular and extracellular milieu, lack of regenerative capacity in the native cells, vast variety of damage routes, and the insufficient time available for treatment have restricted the widespread application of several therapeutic methods in cases of central nervous system injury. Tissue engineering and regenerative medicine have emerged as innovative approaches in the field of nerve regeneration. By combining biomaterials, stem cells, and growth factors, these approaches have provided a platform for developing effective treatments for neural injuries, which can offer the potential to restore neural function, improve patient outcomes, and reduce the need for drugs and invasive surgical procedures. Biomaterials have shown advantages in promoting neural development, inhibiting glial scar formation, and providing a suitable biomimetic neural microenvironment, which makes their application promising in the field of neural regeneration. For instance, bioactive scaffolds loaded with stem cells can provide a biocompatible and biodegradable milieu. Furthermore, stem cells-derived exosomes combine the advantages of stem cells, avoid the risk of immune rejection, cooperate with biomaterials to enhance their biological functions, and exert stable functions, thereby inducing angiogenesis and neural regeneration in patients with traumatic brain injury and promoting the recovery of brain function. Unfortunately, biomaterials have shown positive effects in the laboratory, but when similar materials are used in clinical studies of human central nervous system regeneration, their efficacy is unsatisfactory. Here, we review the characteristics and properties of various bioactive materials, followed by the introduction of applications based on biochemistry and cell molecules, and discuss the emerging role of biomaterials in promoting neural regeneration. Further, we summarize the adaptive biomaterials infused with exosomes produced from stem cells and stem cells themselves for the treatment of traumatic brain injury. Finally, we present the main limitations of biomaterials for the treatment of traumatic brain injury and offer insights into their future potential.

Early Glasgow Coma Scale Score and Prediction of Traumatic Brain Injury: A Secondary Analysis of Three Harmonized Prehospital Randomized Clinical Trials

OBJECTIVES

The prehospital prediction of the radiographic diagnosis of traumatic brain injury (TBI) in hemorrhagic shock patients has the potential to promote early therapeutic interventions. However, the identification of TBI is often challenging and prehospital tools remain limited. While the Glasgow Coma Scale (GCS) score is frequently used to assess the extent of impaired consciousness after injury, the utility of the GCS scores in the early prehospital phase of care to predict TBI in patients with severe injury and concomitant shock is poorly understood.

METHODS

We performed a post-hoc, secondary analysis utilizing data derived from three randomized prehospital clinical trials: the Prehospital Air Medical Plasma trial (PAMPER), the Study of Tranexamic Acid During Air Medical and Ground Prehospital Transport trial (STAAMP), and the Pragmatic Prehospital Type O Whole Blood Early Resuscitation (PPOWER) trial. Patients were dichotomized into two cohorts based on the presence of TBI and then further stratified into three groups based on prehospital GCS score: GCS 3, GCS 4-12, and GCS 13-15. The association between prehospital GCS score and clinical documentation of TBI was assessed.

RESULTS

A total of 1,490 enrolled patients were included in this analysis. The percentage of patients with documented TBI in those with a GCS 3 was 59.5, 42.4% in those with a GCS 4-12, and 11.8% in those with a GCS 13-15. The positive predictive value (PPV) of the prehospital GCS score for the diagnosis of TBI is low, with a GCS of 3 having only a 60% PPV. Hypotension and prehospital intubation are independent predictors of a low prehospital GCS. Decreasing prehospital GCS is strongly associated with higher incidence or mortality over time, irrespective of the diagnosis of TBI.

CONCLUSIONS

The ability to accurately predict the presence of TBI in the prehospital phase of care is essential. The utility of the GCS scores in the early prehospital phase of care to predict TBI in patients with severe injury and concomitant shock is limited. The use of novel scoring systems and improved technology are needed to promote the accurate early diagnosis of TBI.

A systematic review and meta-analysis of major blood protein biomarkers that predict unfavorable outcomes in severe traumatic brain injury

INTRODUCTION

Severe traumatic brain injury (TBI) presentation and late clinical outcomes are usually evaluated by the Glasgow Outcome Scale-Extended (GOS-E), which lacks strong prognostic predictability. Several blood biomarkers have been linked to TBI, such as Tau, GFAP, UCH-L1, S-100B, and NSE. Clinical values of TBI biomarkers have yet to be evaluated in a focused multi-study meta-analysis. We reviewed relevant articles evaluating potential relationships between TBI biomarkers and both early and 6-month outcomes.

METHODS

All PubMed article publications from January 2000 to November 2023 with the search criteria "Protein Biomarker" AND "Traumatic Brain Injury" were included. Amongst all comparative studies, the sensitivity means and range values of biomarkers in predicting CT Rotterdam scores, ICU admission in the early period, or predicting GOS-E < 4 at the 6-month period were calculated from confusion matrices. Sensitivity values were modeled for each biomarker across studies and compared statistically for heterogeneity and differences.

RESULTS

From the 65 articles that met the criteria, 13 were included in this study. Six articles involved early-period TBI outcomes and seven involved 6-month outcomes. In the early period TBI outcomes, GFAP had a superior sensitivity to UCH-L1 and S-100B, and similar sensitivity to the CT Rotterdam score. In the 6-month period TBI outcomes, total Tau and NSE both had significant interstudy heterogeneity, making them inferior to GFAP, phosphorylated Tau, UCH-L1, and S-100B, all four of which had similar sensitivities at 75 %. This sensitivity range at 6-month outcomes was still relatively inferior to the CT Rotterdam score. Total Tau did not show any prognostic advantage at six months with GOS-E < 4, and phosphorylated Tau was similar in its sensitivity to other biomarkers such as GFAP and UCH-L1 and still inferior to the CT Rotterdam score.

CONCLUSION

This data suggests that TBI protein biomarkers do not possess better prognostic value with regards to outcomes.

Admission levels of serum biomarkers have additive and cumulative prognostic value in traumatic brain injury

Elevated levels of CNS-derived serum proteins are associated with poor outcome in traumatic brain injury (TBI), but the value of adding acute serum biomarker levels to common clinical outcome predictors lacks evaluation. We analyzed admission serum samples for Total-Tau (T-Tau), Neurofilament light chain (Nfl), Glial fibrillary acidic protein (GFAP), and Ubiquitin C-terminal hydrolase L1 (UCHL1) in a cohort of 396 trauma patients including 240 patients with TBI. We assessed the independent association of biomarkers with 1-year mortality and 6-12 months Glasgow Outcome Scale Extended (GOSE) score, as well as the additive and cumulative value of biomarkers on Glasgow Coma Scale (GCS) and Marshall Score for outcome prediction. Nfl and T-Tau levels were independently associated with outcome (OR: Nfl = 1.65, p = 0.01; T-Tau = 1.99, p < 0.01). Nfl or T-Tau improved outcome prediction by GCS (Wald Chi, Nfl = 6.8-8.8, p < 0.01; T-Tau 7.2-11.3, p < 0.01) and the Marshall score (Wald Chi, Nfl = 16.2-17.5, p < 0.01; T-Tau 8.7-12.4, p < 0.01). Adding T-Tau atop Nfl further improved outcome prediction in majority of tested models (Wald Chi range 3.8-9.4, p ≤ 0.05). Our data suggest that acute levels of serum biomarkers are independently associated with outcome after TBI and add outcome predictive value to commonly used clinical scores.

Establishment and validation of a bad outcomes prediction model based on EEG and clinical parameters in prolonged disorder of consciousness

Objective

This study aimed to explore the electroencephalogram (EEG) indicators and clinical factors that may lead to poor prognosis in patients with prolonged disorder of consciousness (pDOC), and establish and verify a clinical predictive model based on these factors.

Methods

This study included 134 patients suffering from prolonged disorder of consciousness enrolled in our department of neurosurgery. We collected the data of sex, age, etiology, coma recovery scales (CRS-R) score, complications, blood routine, liver function, coagulation and other laboratory tests, resting EEG data and follow-up after discharge. These patients were divided into two groups: training set (n = 107) and verification set (n = 27). These patients were divided into a training set of 107 and a validation set of 27 for this study. Univariate and multivariate regression analysis were used to determine the factors affecting the poor prognosis of pDOC and to establish nomogram model. We use the receiver operating characteristic (ROC) and calibration curves to quantitatively test the effectiveness of the training set and the verification set. In order to further verify the clinical practical value of the model, we use decision curve analysis (DCA) to evaluate the model.

Result

The results from univariate and multivariate logistic regression analyses suggested that an increased frequency of occurrence microstate A, reduced CRS-R scores at the time of admission, the presence of episodes associated with paroxysmal sympathetic hyperactivity (PSH), and decreased fibrinogen levels all function as independent prognostic factors. These factors were used to construct the nomogram. The training and verification sets had areas under the curve of 0.854 and 0.920, respectively. Calibration curves and DCA demonstrated good model performance and significant clinical benefits in both sets.

Conclusion

This study is based on the use of clinically available and low-cost clinical indicators combined with EEG to construct a highly applicable and accurate model for predicting the adverse prognosis of patients with prolonged disorder of consciousness. It provides an objective and reliable tool for clinicians to evaluate the prognosis of prolonged disorder of consciousness, and helps clinicians to provide personalized clinical care and decision-making for patients with prolonged disorder of consciousness and their families.

Changes in the levels of serum glial fibrillary acidic protein and the correlation with outcomes in severe traumatic brain injury patients

Purpose

Glial fibrillary acidic protein serves as a biomarker indicative of astroglial injury, particularly following instances of severe traumatic brain injury. This study aims to evaluate variations in serum glial fibrillary acidic protein levels within the first 3 days and their correlation with outcomes in patients with severe traumatic brain injury.

Subjects and methods

Thirty-nine patients with severe traumatic brain injury were enrolled in the study. Their blood samples were collected at six distinct time points: T0 (upon admission), T1, T2, T3, T4, and T5 (6-, 12-, 24-, 48-, and 72-h post-admission, respectively). The blood samples were run for the quantification of serum glial fibrillary acidic protein levels and other biochemical tests. All patients were closely watched and the outcomes at discharge were evaluated.

Results

Glial fibrillary acidic protein levels tend to increase gradually from the time of admission to 48 h post-admission and then decrease at 72 h post-admission. Glial fibrillary acidic protein T2 is correlated with Acute Physiology and Chronic Health Evaluation II score, lactate, Simplified Acute Physiology Score II score and outcome. Glial fibrillary acidic protein max correlated with lactate, Acute Physiology and Chronic Health Evaluation II score, Simplified Acute Physiology Score II score, and outcome. Glasgow Coma Score at admission and glial fibrillary acidic protein T2 (OR = 1.034; p = 0.025), T3 (OR = 1.029; p = 0.046), T4 (OR = 1.006; p = 0.032), T5 (OR = 1.012; p = 0.048) and glial fibrillary acidic protein max (OR = 1.005; p = 0.010) were independent factors that have significant prognostic value in mortality in patients with severe traumatic brain injury. The predictive model in predicting mortality had the highest area under the curve based on glial fibrillary acidic protein T2 and Glasgow Coma Score T0 with an area under the curve of 0.904 and p < 0.001. In the multivariable regression model, glial fibrillary acidic protein max was associated with Glasgow score (p < 0.001; VIF = 1.585), lactate T0 (p = 0.024; VIF = 1.163), Acute Physiology and Chronic Health Evaluation II score (p = 0.037; VIF = 1.360), and Rotterdam score (p = 0.044; VIF = 1.713).

Conclusion

Glial fibrillary acidic protein levels tend to increase gradually from the time of admission to 48 h post-admission then decreases at 72 h post-admission. Glial fibrillary acidic protein T2, T3, T4, T5, and glial fibrillary acidic protein max were independent factors with significant prognostic mortality values in patients with severe traumatic brain injury.

Low Prognostic Nutritional Index Predicts In-Hospital Complications and Case Fatality in Patients with Spontaneous Intracerebral Hemorrhage: A Retrospective Study

BACKGROUND

Spontaneous intracerebral hemorrhage (ICH) is associated with high case fatality and significant healthcare costs. Recent studies emphasize the critical role of nutritional status in affecting outcomes in neurological disorders. This study investigates the relationship between the Prognostic Nutrition Index (PNI) and in-hospital complications and case fatality among patients with ICH.

METHODS

A retrospective analysis was performed using data from the Changhua Christian Hospital Clinical Research Database between January 2015 and December 2022. Patients under 20 or over 100 years of age or with incomplete medical data were excluded. We utilized restricted cubic spline models, Kaplan-Meier survival analysis, and ROC analysis to assess the association between PNI and clinical outcomes. Propensity score matching analysis was performed to balance these clinical variables between groups.

RESULTS

In this study, 2402 patients with spontaneous ICH were assessed using the median PNI value of 42.77. The cohort was evenly divided between low and high PNI groups, predominantly male (59.1%), with an average age of 64 years. Patients with lower PNI scores at admission had higher in-hospital complications and increased 28- and 90-day case fatality rates.

CONCLUSIONS

Our study suggests that PNI could serve as a valuable marker for predicting medical complications and case fatality in patients with spontaneous ICH.

Importance of AIM2 as a serum marker for reflecting severity and predicting a poor outcome of human severe traumatic brain injury: A prospective longitudinal cohort study

BACKGROUND

Absent in melanoma 2 (AIM2) participates in neuroinflammation. Here, the prognostic significance of serum AIM2 was explored in severe traumatic brain injury (sTBI).

METHODS

A total of 135 sTBI patients and 80 healthy controls were recruited in this prospective cohort study. Serum C-reactive protein (CRP) and AIM2 levels were measured. Glasgow Coma Scale (GCS) and Rotterdam computed tomography (CT) classification were recorded as the severity indicators. Prognostic parameters were posttraumatic six-month extended Glasgow outcome scale (GOSE) scores and poor outcome (GOSE scores of 1-4).

RESULTS

As opposed to controls, there were significantly elevated serum AIM2 levels after sTBI. Serum AIM2 levels were independently correlated with serum CRP levels, GCS scores, Rotterdam CT scores, GOSE scores and poor outcome. Also, serum AIM2 levels were efficiently predictive of poor outcome under the receiver operating characteristic (ROC) curve. Under the restricted cubic spline, serum AIM2 levels were linearly correlated with risk of poor outcome. Using subgroup analysis, serum AIM2 levels did not significantly interact with other indices, such as age, gender, alcohol drinking, cigarette smoking, etc. Also, combination model, in which serum AIM2, GCS scores and Rotterdam CT scores were merged, was outlined using nomogram and performed well under calibration curve, ROC curve and decision curve.

CONCLUSIONS

Raised serum AIM2 levels after sTBI, in intimate correlation with systemic inflammation and trauma severity, are independently discriminative of posttraumatic six-month neurological outcome, substantializing serum AIM2 as an inflammatory prognostic biomarker of sTBI.

Efficacy and safety of tranexamic acid in acute traumatic brain injury: A meta-analysis of randomized controlled trials

INTRODUCTION

Tranexamic acid (TXA) holds a pivotal role in the therapeutic approach to traumatic conditions. Nevertheless, its precise influence on diminishing mortality and limiting the progression of intracranial hemorrhage (ICH) during the treatment of traumatic brain injury (TBI) remains indeterminate.

METHODS

PubMed, EMBASE, Cochrane Library, and Web of Science were searched for randomized controlled trials that compared TXA and a placebo in adults with TBI up to September 31, 2023. Two authors independently abstracted the data and assessed the quality of evidence. Additionally, subgroup analyses were performed to assess outcomes with low heterogenety.

RESULTS

Our search strategy yielded 11,299 patients from 11 studies. The result showed that TXA had no effect on mortality (RR 0.93 [0.86, 1.00], p = 0.06; I2: 0%, p = 0.79), poor clinical outcomes (RR 0.92 [0.78, 1.09], p = 0.34; I2: 0%, p = 0.40), adverse events (RR 0.94 [0.83, 1.07], p = 0.34; I2: 48%, p = 0.10), vascular occlusive events (RR 0.85 [0.68, 1.06], p = 0.16; I2: 32%, p = 0.22), pulmonary embolism (RR 0.76 [0.47, 1.22], p = 0.26; I2: 0%, p = 0.83), seizure (RR 1.11 [0.92, 1.35], p = 0.27; I2: 0%, p = 0.49) and hemorrhagic complications (RR 0.78 [0.55, 1.09], p = 0.14; I2: 0%, p = 0.42). TXA might reduce the rate of hemorrhagic expansion (RR 0.83 [0.70, 0.99], p = 0.03; I2: 18%, p = 0.29) and mean hemorrhage volume (SMD -0.39 [-0.60, -0.18], p <0.001; I2: 44%, p = 0.13).When the time interval from symptom onset to treatment was <3 h, TXA reduced mean hemorrhage volume (SMD -0.51 [-0.81, -0.20], p = 0.001; I2: 0%, p = 0.94).

CONCLUSIONS

TXA did not elevate the risk of adverse event, however, the lack of reduction in mortality and the poor clinical outcomes constrain the value of clinical application. Early administration of TXA (within 3 h) may significantly decrease the likelihood of ICH growth in patients with TBI.

Biomarkers in Acute Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Traumatic brain injury (TBI) stands as a significant contributor to traumatic death and disability worldwide. In recent years, researchers have identified biomarkers to gauge useful outcomes in TBI patients. However, the enigma of timely sample collection to measure the biomarkers remains a controversial point in the case of TBI, unlike other degenerative diseases like Alzheimer's disease and Parkinson's disease, where we can collect the sample at any point in time. The purpose of this study is to evaluate the sensitivity of biomarkers in TBI concerning time of injury by analyzing recent available data on biomarkers in the medical literature. A total of 2,256 studies were initially retrieved from the search engine. After an initial screening, only 1,750 unique articles remained. After excluding review articles, animal studies, meta-analysis, and studies with children (screened by title and abstract), 30 kinds of literature were found relevant to search the required variables. Further 16 studies were excluded due to the nonavailability of complete variables or data. Finally, 14 studies remained and were included in the analysis. This study has analyzed the four most commonly described biomarkers for TBI in the literature: glial fibrillary acidic protein (GFAP), S100 calcium-binding protein B, ubiquitin carboxy-terminal hydrolase L1, and Tau. According to this statistical analysis, all biomarkers included in the study have shown their serum levels after trauma. So, all these biomarkers can be used for further study in the outcome prediction and diagnosis of TBI patients. The meta-analysis suggests that the best biomarker for TBI is Tau in cases where sample collection is done within 24 hours, while GFAP is the best biomarker to be studied for TBI if sample collection is done 24 hours after trauma.

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.

Development of a time-resolved immunochromatographic test strip for rapid and quantitative determination of GFAP in serum

Glial fibrillary acidic protein (GFAP) in serum has been shown as a biomarker of traumatic brain injury (TBI) which is a significant global public health concern. Accurate and rapid detection of serum GFAP is critical for TBI diagnosis. In this study, a time-resolved fluorescence immunochromatographic test strip (TRFIS) was proposed for the quantitative detection of serum GFAP. This TRFIS possessed excellent linearity ranging from 0.05 to 2.5 ng/mL for the detection of serum GFAP and displayed good linearity (Y = 598723X + 797198, R2 = 0.99), with the lowest detection limit of 16 pg/mL. This TRFIS allowed for quantitative detection of serum GFAP within 15 min and showed high specificity. The intra-batch coefficient of variation (CV) and the inter-batch CV were both < 4.0%. Additionally, this TRFIS was applied to detect GFAP in the serum samples from healthy donors and patients with cerebral hemorrhage, and the results of TRFIS could efficiently discern the patients with cerebral hemorrhage from the healthy donors. Our developed TRFIS has the characteristics of high sensitivity, high accuracy, and a wide linear range and is suitable for rapid and quantitative determination of serum GFAP on-site.

GFAP point-of-care measurement for prehospital diagnosis of intracranial hemorrhage in acute coma

BACKGROUND

Prehospital triage and treatment of patients with acute coma is challenging for rescue services, as the underlying pathological conditions are highly heterogenous. Recently, glial fibrillary acidic protein (GFAP) has been identified as a biomarker of intracranial hemorrhage. The aim of this prospective study was to test whether prehospital GFAP measurements on a point-of-care device have the potential to rapidly differentiate intracranial hemorrhage from other causes of acute coma.

METHODS

This study was conducted at the RKH Klinikum Ludwigsburg, a tertiary care hospital in the northern vicinity of Stuttgart, Germany. Patients who were admitted to the emergency department with the prehospital diagnosis of acute coma (Glasgow Coma Scale scores between 3 and 8) were enrolled prospectively. Blood samples were collected in the prehospital phase. Plasma GFAP measurements were performed on the i-STAT Alinity® (Abbott) device (duration of analysis 15 min) shortly after hospital admission.

RESULTS

143 patients were enrolled (mean age 65 ± 20 years, 42.7% female). GFAP plasma concentrations were strongly elevated in patients with intracranial hemorrhage (n = 51) compared to all other coma etiologies (3352 pg/mL [IQR 613-10001] vs. 43 pg/mL [IQR 29-91.25], p < 0.001). When using an optimal cut-off value of 101 pg/mL, sensitivity for identifying intracranial hemorrhage was 94.1% (specificity 78.9%, positive predictive value 71.6%, negative predictive value 95.9%). In-hospital mortality risk was associated with prehospital GFAP values.

CONCLUSION

Increased GFAP plasma concentrations in patients with acute coma identify intracranial hemorrhage with high diagnostic accuracy. Prehospital GFAP measurements on a point-of-care platform allow rapid stratification according to the underlying cause of coma by rescue services. This could have major impact on triage and management of these critically ill patients.

Common Data Elements for Disorders of Consciousness: Recommendations from the Working Group on Biospecimens and Biomarkers

BACKGROUND

In patients with disorders of consciousness (DoC), laboratory and molecular biomarkers may help define endotypes, identify therapeutic targets, prognosticate outcomes, and guide patient selection in clinical trials. We performed a systematic review to identify common data elements (CDEs) and key design elements (KDEs) for future coma and DoC research.

METHODS

The Curing Coma Campaign Biospecimens and Biomarkers work group, composed of seven invited members, reviewed existing biomarker and biospecimens CDEs and conducted a systematic literature review for laboratory and molecular biomarkers using predetermined search words and standardized methodology. Identified CDEs and KDEs were adjudicated into core, basic, supplemental, or experimental CDEs per National Institutes of Health classification based on level of evidence, reproducibility, and generalizability across different diseases through a consensus process.

RESULTS

Among existing National Institutes of Health CDEs, those developed for ischemic stroke, traumatic brain injury, and subarachnoid hemorrhage were most relevant to DoC and included. KDEs were common to all disease states and included biospecimen collection time points, baseline indicator, biological source, anatomical location of collection, collection method, and processing and storage methodology. Additionally, two disease core, nine basic, 24 supplemental, and 59 exploratory biomarker CDEs were identified. Results were summarized and generated into a Laboratory Data and Biospecimens Case Report Form (CRF) and underwent public review. A final CRF version 1.0 is reported here.

CONCLUSIONS

Exponential growth in biomarkers development has generated a growing number of potential experimental biomarkers associated with DoC, but few meet the quality, reproducibility, and generalizability criteria to be classified as core and basic biomarker and biospecimen CDEs. Identification and adaptation of KDEs, however, contribute to standardizing methodology to promote harmonization of future biomarker and biospecimens studies in DoC. Development of this CRF serves as a basic building block for future DoC studies.

A predictive model for awakening in patients with prolonged disorders of consciousness after craniocerebral injury

This study aimed to develop and validate a nomogram to predict awakening at 1 year in patients with prolonged disorders of consciousness (pDOC). We retrospectively analyzed the data of 381 patients with pDOC at 2 centers. The data were randomly divided into training and validation sets using a ratio of 6:4. For the training set, univariate and multivariate logical regression analyses were used to identify the predictive variables. Receiver operating characteristic curves, calibration curves, and a decision curve analysis were utilized to assess the predictive accuracy, discriminative ability, and clinical utility of the model, respectively. The final model included age, Glasgow Coma Scale score, serum albumin level, and computed tomography midline shift, all of which had a significant effect on awakening after pDOC. For the 1-year awakening in the training set, the model had good discriminative power, with an area under the curve of 0.733 (95% confidence interval: 0.667-0.789). For the validation set, the area under the curve for 1-year awakening was 0.721 (95% confidence interval: 0.617-0.826). Model performance was good for both the training and validation sets according to calibration plots and decision curve analysis. We developed a precise, effective nomogram to assist clinicians in better assessing patients' outcomes, guiding clinical judgment, and personalizing the therapeutic process.

TXA does not affect levels of TBI-related biomarkers in blunt TBI with ICH: A secondary analysis of the prehospital TXA for TBI trial

BACKGROUND

Brain specific biomarkers such as glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase L1 (UCH-L1), and microtubule-associated protein-2 (MAP-2) have been identified as tools for diagnosis in traumatic brain injury (TBI). Tranexamic acid (TXA) has been shown to decrease mortality in patients with intracranial hemorrhage (ICH). The effect of TXA on these biomarkers is unknown. We investigated whether TXA affects levels of GFAP, UCH-L1, and MAP-2, and whether biomarker levels are associated with mortality in patients receiving TXA.

METHODS

Patients enrolled in the prehospital TXA for TBI trial had GFAP, UCHL-1 and MAP-2 levels drawn at 0 hour and 24 hours postinjury (n = 422). Patients with ICH from blunt trauma with a GCS <13 and SBP >90 were randomized to placebo, 2 g TXA bolus, or 1 g bolus +1 g/8 hours TXA infusion. Associations of TXA and 24-hour biomarker change were assessed with multivariate linear regression. Association of biomarkers with 28-day mortality was assessed with multivariate logistic regression. All models were controlled for age, GCS, ISS, and AIS head.

RESULTS

Administration of TXA was not associated with a change in biomarkers over 24 hours postinjury. Changes in biomarker levels were associated with AIS head and age. On admission, higher GFAP (odds ratio [OR], 1.75; confidence interval [CI], 1.31-2.38; p < 0.001) was associated with increased 28-day mortality. At 24 hours postinjury, higher levels of GFAP (OR, 2.09; CI, 1.37-3.30; p < 0.001 and UCHL-1 (OR, 2.98; CI, 1.77-5.25; p < 0.001) were associated with mortality. A change in UCH levels from 0 hour to 24 hours postinjury was also associated with increased mortality (OR, 1.68; CI, 1.15-2.49; p < 0.01).

CONCLUSION

Administration of TXA does not impact change in GFAP, UCHL-1, or MAP-2 during the first 24 hours after blunt TBI with ICH. Higher levels of GFAP and UCH early after injury may help identify patients at high risk for 28-day mortality.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level III.

Serial Measurements of Serum Glial Fibrillary Acidic Protein in Moderate-Severe Traumatic Brain Injury: Potential Utility in Providing Insights into Secondary Insults and Long-Term Outcome

In patients with traumatic brain injury (TBI), serum biomarkers may have utility in assessing the evolution of secondary brain injury. A panel of nine brain-injury- associated biomarkers was measured in archived serum samples over 10 days post-injury from 100 patients with moderate-severe TBI. Among the biomarkers evaluated, serum glial fibrillary acidic protein (GFAP) had the strongest associations with summary measures of acute pathophysiology, including intracranial pressure (ICP), cerebral perfusion pressure (CPP), and brain tissue pO2 (PbtO2). Group based trajectory (TRAJ) analysis was used to identify three distinct GFAP subgroups. The low TRAJ group (n = 23) had peak levels of 9.4 + 1.2 ng/mL that declined rapidly. The middle TRAJ group (n = 48) had higher peak values (31.5 + 5.0 ng/mL) and a slower decline over time. The high TRAJ group (n = 26) had very high, sustained peak values (59.6 + 12.5 ng/mL) that even rose among some patients over 10 days. Patients in the high TRAJ group had significantly higher mortality rate than patients in low and middle TRAJ groups (26.9% vs. 7.0%, p = 0.028). The frequency of poor neurological outcome (Glasgow Outcome Score Extended [GOS-E] 1-4) was 88.5% in the high TRAJ group, 54.2% in the middle TRAJ group, and 30.4% in the low TRAJ group (p < 0.001). ICP was highest in the high TRAJ group (median 17.6 mm Hg), compared with 14.4 mmHg in the low and 15.9 mm Hg in middle TRAJ groups (p = 0.002). High TRAJ patients spent the longest time with ICP >25 mm Hg, median 23 h, compared with 2 and 6 h in the low and middle TRAJ groups (p = 0.006), and the longest time with ICP >30 mm Hg, median 5 h, compared with 0 and 1 h in the low and middle TRAJ groups, respectively (p = 0.013). High TRAJ group patients more commonly required tier 2 or 3 treatment to control ICP. The high TRAJ group had the longest duration when CPP was <50 mm Hg (p = 0.007), and PbtO2 was <10 mm Hg (p = 0.002). Logistical regression was used to study the relationship between temporal serum GFAP patterns and 6-month GOS-E. Here, the low and middle TRAJ groups were combined to form a low-risk group, and the high TRAJ group was designated the high-risk group. High TRAJ group patients had a greater chance of a poor 6-month GOS-E (p < 0.0001). When adjusting for baseline injury characteristics, GFAP TRAJ group membership remained associated with GOS-E (p = 0.003). When an intensive care unit (ICU) injury burden score, developed to quantify physiological derangements, was added to the model, GFAP TRAJ group membership remained associated with GOS-E (p = 0.014). Mediation analysis suggested that ICU burden scores were in the causal pathway between TRAJ group and 6-month mortality or GOS-E. Our results suggest that GFAP may be useful to monitor serially in moderate-severe TBI patients. Future studies in larger cohorts are needed to confirm these results.

Outlier Analysis for Acute Blood Biomarkers of Moderate and Severe Traumatic Brain Injury

Blood biomarkers have been studied to improve the clinical assessment and prognostication of patients with moderate-severe traumatic brain injury (mo/sTBI). To assess their clinical usability, one needs to know of potential factors that might cause outlier values and affect clinical decision making. In a prospective study, we recruited patients with mo/sTBI (n = 85) and measured the blood levels of eight protein brain pathophysiology biomarkers, including glial fibrillary acidic protein (GFAP), S100 calcium-binding protein B (S100B), neurofilament light (Nf-L), heart-type fatty acid-binding protein (H-FABP), interleukin-10 (IL-10), total tau (T-tau), amyloid β40 (Aβ40) and amyloid β42 (Aβ42), within 24 h of admission. Similar analyses were conducted for controls (n = 40) with an acute orthopedic injury without any head trauma. The patients with TBI were divided into subgroups of normal versus abnormal (n = 9/76) head computed tomography (CT) and favorable (Glasgow Outcome Scale Extended [GOSE] 5-8) versus unfavorable (GOSE <5) (n = 38/42, 5 missing) outcome. Outliers were sought individually from all subgroups from and the whole TBI patient population. Biomarker levels outside Q1 - 1.5 interquartile range (IQR) or Q3 + 1.5 IQR were considered as outliers. The medical records of each outlier patient were reviewed in a team meeting to determine possible reasons for outlier values. A total of 29 patients (34%) combined from all subgroups and 12 patients (30%) among the controls showed outlier values for one or more of the eight biomarkers. Nine patients with TBI and five control patients had outlier values in more than one biomarker (up to 4). All outlier values were > Q3 + 1.5 IQR. A logical explanation was found for almost all cases, except the amyloid proteins. Explanations for outlier values included extremely severe injury, especially for GFAP and S100B. In the case of H-FABP and IL-10, the explanation was extracranial injuries (thoracic injuries for H-FABP and multi-trauma for IL-10), in some cases these also were associated with abnormally high S100B. Timing of sampling and demographic factors such as age and pre-existing neurological conditions (especially for T-tau), explained some of the abnormally high values especially for Nf-L. Similar explanations also emerged in controls, where the outlier values were caused especially by pre-existing neurological diseases. To utilize blood-based biomarkers in clinical assessment of mo/sTBI, very severe or fatal TBIs, various extracranial injuries, timing of sampling, and demographic factors such as age and pre-existing systemic or neurological conditions must be taken into consideration. Very high levels seem to be often associated with poor prognosis and mortality (GFAP and S100B).

The game changer: UCH-L1 and GFAP-based blood test as the first marketed in vitro diagnostic test for mild traumatic brain injury

INTRODUCTION

Major organ-based in vitro diagnostic (IVD) tests like ALT/AST for the liver and cardiac troponins for the heart are established, but an approved IVD blood test for the brain has been missing, highlighting a gap in medical diagnostics.

AREAS COVERED

In response to this need, Abbott Diagnostics secured FDA clearance in 2021 for the i-STAT Alinity™, a point-of-care plasma blood test for mild traumatic brain injury (TBI). BioMerieux VIDAS, also approved in Europe, utilizes two brain-derived protein biomarkers: neuronal ubiquitin C-terminal hydrolase-L1 (UCH-L1) and glial fibrillary acidic protein (GFAP). These biomarkers, which are typically present in minimal amounts in healthy individuals, are instrumental in diagnosing mild TBI with potential brain lesions. The study explores how UCH-L1 and GFAP levels increase significantly in the bloodstream following traumatic brain injury, aiding in early and accurate diagnosis.

EXPERT OPINION

The introduction of the i-STAT Alinity™ and the Biomerieux VIDAS TBI blood tests mark a groundbreaking development in TBI diagnosis. It paves the way for the integration of TBI biomarker tools into clinical practice and therapeutic trials, enhancing the precision medicine approach by generating valuable data. This advancement is a critical step in addressing the long-standing gap in brain-related diagnostics and promises to revolutionize the management and treatment of mild TBI.

Predictive Performance of Neuron-Specific Enolase (NSE) for Survival after Resuscitation from Cardiac Arrest: A Systematic Review and Meta-Analysis

The prediction of outcomes following cardiac arrest continues to provide significant difficulties. A preferred strategy involves adopting a multimodal approach, which encompasses the careful evaluation of the biomarker neuron-specific enolase (NSE). This systematic review and meta-analysis aimed to gather and summarize new and existing evidence on the prediction effect of neuron-specific enolase for survival to hospital discharge among adult patients with cardiac arrest. We searched PubMed Central, Scopus, EMBASE databases, and the Cochrane Library without language restrictions from their inceptions until 30 October 2023 and checked the reference lists of the included studies. Pooled results were reported as standardized mean differences (SMDs) and were presented with corresponding 95% confidence intervals (CIs). The primary outcome was survival to hospital discharge (SHD). Eighty-six articles with 10,845 participants were included. NSE showed a notable degree of specificity in its ability to predict mortality as well as neurological status among individuals who experienced cardiac arrest (p < 0.05). This study demonstrates the ability to predict fatality rates and neurological outcomes, both during the time of admission and at various time intervals after cardiac arrest. The use of NSE in a multimodal neuroprognostication algorithm has promise in improving the accuracy of prognoses for persons who have undergone cardiac arrest.

Outcomes and physiologic responses associated with ketamine administration after traumatic brain injury in the United States and Canada: a retrospective analysis

Purpose

Ketamine has historically been contraindicated in traumatic brain injury (TBI) due to concern for raising intracranial pressure. However, it is increasingly being used in TBI due to the favorable respiratory and hemodynamic properties. To date, no studies have evaluated whether ketamine administered in subjects with TBI is associated with patient survival or disability.

Methods

We performed a retrospective analysis of data from the multicenter Prehospital Tranexamic Acid Use for Traumatic Brain Injury trial, comparing ketamine-exposed and ketamine-unexposed TBI subjects to determine whether an association exists between ketamine administration and mortality, as well as secondary outcome measures.

Results

We analyzed 841 eligible subjects from the original study, of which 131 (15.5%) received ketamine. Ketamine-exposed subjects were younger (37.3±16.9 years vs. 42.0±18.6 years, P=0.037), had a worse initial Glasgow Coma Scale score (7±3 vs. 8±4, P=0.003), and were more likely to be intubated than ketamine-unexposed subjects (88.5% vs. 44.2%, P<0.001). Overall, there was no difference in mortality (12.2% vs. 15.5%, P=0.391) or disability measures between groups. Ketamine-exposed subjects had significantly fewer instances of elevated intracranial pressure (ICP) compared to ketamine-unexposed subjects (56.3% vs. 82.3%, P=0.048). In the very rare outcomes of cardiac events and seizure activity, seizure activity was statistically more likely in ketamine-exposed subjects (3.1% vs. 1.0%, P=0.010). In the intracranial hemorrhage subgroup, cardiac events were more likely in ketamine-exposed subjects (2.3% vs. 0.2%, P=0.025). Ketamine exposure was associated with a smaller increase in TBI protein biomarker concentrations.

Conclusions

Ketamine administration was not associated with worse survival or disability despite being administered to more severely injured subjects. Ketamine exposure was associated with reduced elevations of ICP, more instances of seizure activity, and lower concentrations of TBI protein biomarkers.

The relationship between hemoglobin/red blood cell distribution width ratio and mortality in patients with intracranial hemorrhage: a possible protective effect for the elderly?

Intracranial hemorrhage (ICH) is a neurological emergency with a poor prognosis. This study aimed to understand the association between hemoglobin levels, red blood cell distribution width ratio (HRR), and mortality in patients with ICH. Information on patients with ICH was extracted from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Cox proportional risk models were used to assess the relationship between HRR and 28-day and 90-day mortality, and constructed by adjusting for relevant covariates. Segmented regression models and smoothing curves were used to analyze the linear relationship between HRR and mortality. This study recruited 4,716 patients with ICH. The HRR Q4 group was negatively associated with the 28- and 90-day mortality. For patients aged > 65 years, the right-hand threshold inflection points of the HRR were 0.92 and 0.93, respectively, which were negatively associated with 28-day mortality (HR:0.06, 95% CI 0.01, 0.35, p = 0.0016) and with 90-day mortality (p = 0.0006). In the non-linear model, both 28-day mortality (HR, 0.17; 95% CI 0.04-0.75, p = 0.0191; HRR > 0.89) and 90-day mortality (HR, 0.13; 95% CI 0.04-0.49, p = 0.0022; HRR > 0.85) were associated in men. In the subgroup analysis, the negative association between HRR and mortality was more pronounced in patients > 65 years of age, as well as in patients with non-dementia, diabetes, and malignant cancer. We found a non-linear relationship between mortality and the HRR in elderly patients, and a higher HRR was negatively associated with mortality in patients with ICH.

Blood-Based Biomarkers for Neuroprognostication in Acute Brain Injury

Acute brain injury causes loss of functionality in patients that often is devastating. Predicting the degree of functional loss and overall prognosis requires a multifaceted approach to help patients, and more so their families, make important decisions regarding plans and goals of care. A variety of blood-based markers have been studied as one aspect of this determination. In this review, we discuss CNS-derived and systemic markers that have been studied for neuroprognostication purposes. We discuss the foundation of each protein, the conditions in which it has been studied, and how the literature has used these markers for interpretation. We also discuss challenges to using each marker in each section as well.

Early preclinical plasma protein biomarkers of brain trauma are influenced by early seizures and levetiracetam

OBJECTIVE

We used the lateral fluid percussion injury (LFPI) model of moderate-to-severe traumatic brain injury (TBI) to identify early plasma biomarkers predicting injury, early post-traumatic seizures or neuromotor functional recovery (neuroscores), considering the effect of levetiracetam, which is commonly given after severe TBI.

METHODS

Adult male Sprague-Dawley rats underwent left parietal LFPI, received levetiracetam (200 mg/kg bolus, 200 mg/kg/day subcutaneously for 7 days [7d]) or vehicle post-LFPI, and were continuously video-EEG recorded (n = 14/group). Sham (craniotomy only, n = 6), and naïve controls (n = 10) were also used. Neuroscores and plasma collection were done at 2d or 7d post-LFPI or equivalent timepoints in sham/naïve. Plasma protein biomarker levels were determined by reverse phase protein microarray and classified according to injury severity (LFPI vs. sham/control), levetiracetam treatment, early seizures, and 2d-to-7d neuroscore recovery, using machine learning.

RESULTS

Low 2d plasma levels of Thr231 -phosphorylated tau protein (pTAU-Thr231 ) and S100B combined (ROC AUC = 0.7790) predicted prior craniotomy surgery (diagnostic biomarker). Levetiracetam-treated LFPI rats were differentiated from vehicle treated by the 2d-HMGB1, 2d-pTAU-Thr231 , and 2d-UCHL1 plasma levels combined (ROC AUC = 0.9394) (pharmacodynamic biomarker). Levetiracetam prevented the seizure effects on two biomarkers that predicted early seizures only among vehicle-treated LFPI rats: pTAU-Thr231 (ROC AUC = 1) and UCHL1 (ROC AUC = 0.8333) (prognostic biomarker of early seizures among vehicle-treated LFPI rats). Levetiracetam-resistant early seizures were predicted by high 2d-IFNγ plasma levels (ROC AUC = 0.8750) (response biomarker). 2d-to-7d neuroscore recovery was best predicted by higher 2d-S100B, lower 2d-HMGB1, and 2d-to-7d increase in HMGB1 or decrease in TNF (P < 0.05) (prognostic biomarkers).

SIGNIFICANCE

Antiseizure medications and early seizures need to be considered in the interpretation of early post-traumatic biomarkers.

Determining the value of early measurement of interleukin-10 in predicting the absence of brain lesions in CT scans of patients with mild traumatic brain injury

Blood-based biomarkers were recently proposed as predictors of traumatic brain injury (TBI) outcomes. This would be a critical step forward since the majority of TBI events are mild and structural brain damage in this group may be missed by current brain imaging methods. We sought to determine the performance of early measurement of interleukin-10 (IL-10) to distinguish computed tomography (CT)-positive from negative patients with mild TBI. We designed a single-center prospective observational study, which enrolled consecutive patients classed with mild TBI according to Glasgow Coma Scale [GCS] scores and appearance of at least one clinical symptom. Serum IL-10 levels were measured <3 h post hospital admission. The performance of IL-10 levels in correctly classifying patients was evaluated. IL-10 levels were significantly higher in the group with positive CT scans (p < 0.001). With sensitivity set at 100%, the specificity of IL-10 was only 38.1%. However, the specificities of IL-10 for prediction of negative and positive cases increased to 59% and 49%, respectively, when both parameters were assessed within 90 min of admission. For mild TBI patients between 36 and 66 years, classification performance increased significantly at the 100% sensitivity level with a specificity of 93%. Our results suggest that IL-10 may be an easily accessible clinically useful diagnostic biomarker that can distinguish between mild TBI patients with and without structural brain damage with higher effectiveness when lower times of blood sampling are employed and patients are between 36 and 66 years of age.

Abusive Head Trauma Animal Models: Focus on Biomarkers

Abusive head trauma (AHT) is a serious traumatic brain injury and the leading cause of death in children younger than 2 years. The development of experimental animal models to simulate clinical AHT cases is challenging. Several animal models have been designed to mimic the pathophysiological and behavioral changes in pediatric AHT, ranging from lissencephalic rodents to gyrencephalic piglets, lambs, and non-human primates. These models can provide helpful information for AHT, but many studies utilizing them lack consistent and rigorous characterization of brain changes and have low reproducibility of the inflicted trauma. Clinical translatability of animal models is also limited due to significant structural differences between developing infant human brains and the brains of animals, and an insufficient ability to mimic the effects of long-term degenerative diseases and to model how secondary injuries impact the development of the brain in children. Nevertheless, animal models can provide clues on biochemical effectors that mediate secondary brain injury after AHT including neuroinflammation, excitotoxicity, reactive oxygen toxicity, axonal damage, and neuronal death. They also allow for investigation of the interdependency of injured neurons and analysis of the cell types involved in neuronal degeneration and malfunction. This review first focuses on the clinical challenges in diagnosing AHT and describes various biomarkers in clinical AHT cases. Then typical preclinical biomarkers such as microglia and astrocytes, reactive oxygen species, and activated N-methyl-D-aspartate receptors in AHT are described, and the value and limitations of animal models in preclinical drug discovery for AHT are discussed.

Prognostic Role of Serum Soluble Tim-3 in Severe Traumatic Brain Injury: A Prospective Observational Study

OBJECTIVE

T cell immunoglobulin and mucin domain-3 (Tim-3) may be implicated in neuroinflammation. Herein, we attempted to discern the role of serum soluble (s) Tim-3 as an inflammatory prognostic biomarker of severe traumatic brain injury (sTBI).

METHODS

In this prospective observational study of 112 sTBI patients and 112 controls, serum sTim-3 levels were determined, Rotterdam computed tomography (CT) classification and Glasgow coma scale (GCS) were selected as the two severity indicators, serum C-reactive protein (CRP) was regarded as an inflammatory biomarker, and poor prognosis was referred to as extended Glasgow outcome scale (GOSE) scores 1-4 at 180 days after trauma.

RESULTS

Serum sTim-3 levels were markedly higher in patients than in controls (median, 4.2 ng/mL versus 0.7 ng/mL; P<0.001). Serum sTim-3 levels of patients were independently related to Rotterdam CT scores (β=1.126), GCS scores (β=-0.589), serum CRP levels (β=0.155) and GOSE scores (β=-0.211). Serum sTim-3 appeared as an independent predictor of post-traumatic 180-day mortality (odds ratio=1.289), overall survival (hazard ratio=1.208) and poor prognosis (odds ratio=1.293). Serum sTim-3 levels discriminated patients at risk of post-injury 180-day mortality and poor prognosis with areas under curve (AUCs) at 0.753 and 0.782, respectively. Serum sTim-3 levels combined with GCS scores and Rotterdam CT scores (AUC=0.869) exhibited significantly higher AUC than Rotterdam CT scores (P=0.026), but not than GCS scores (P=0.181) for death prediction and their combination (AUC=0.895) had significantly higher AUC than GCS scores (P=0.036) or Rotterdam CT scores (P=0.005) for outcome prediction.

CONCLUSION

Elevated serum sTim-3 levels, in close correlation with traumatic severity and inflammation, are substantially associated with long-term death and poor outcome, indicating that serum sTim-3, as an inflammatory biomarker, may be of clinical significance in severity assessment and prediction of prognosis following sTBI.

Traumatic Brain Injuries: Comprehensive Management of Complex Clinical Scenarios

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The efficacy of tranexamic acid treatment with different time and doses for traumatic brain injury: a systematic review and meta-analysis

OBJECTIVE

Tranexamic acid (TXA) plays a significant role in the treatment of traumatic diseases. However, its effectiveness in patients with traumatic brain injury (TBI) seems to be contradictory, according to the recent publication of several meta-analyses. We aimed to determine the efficacy of TXA treatment at different times and doses for TBI treatment.

METHODS

PubMed, MEDLINE, EMBASE, Cochrane Library, and Google Scholar were searched for randomized controlled trials that compared TXA and a placebo in adults and adolescents (≥ 15 years of age) with TBI up to January 31, 2022. Two authors independently abstracted the data and assessed the quality of evidence.

RESULTS

Of the identified 673 studies, 13 involving 18,675 patients met our inclusion criteria. TXA had no effect on mortality (risk ratio (RR) 0.99; 95% confidence interval (CI) 0.92-1.06), adverse events (RR 0.93, 95% Cl 0.76-1.14), severe TBI (Glasgow Coma Scale score from 3 to 8) (RR 0.99, 95% Cl 0.94-1.05), unfavorable Glasgow Outcome Scale (GOS < 4) (RR 0.96, 95% Cl 0.82-1.11), neurosurgical intervention (RR 1.11, 95% Cl 0.89-1.38), or rebleeding (RR 0.97, 95% Cl 0.82-1.16). TXA might reduce the mean hemorrhage volume on subsequent imaging (standardized mean difference, -0.35; 95% CI [-0.62, -0.08]).

CONCLUSION

TXA at different times and doses was associated with reduced mean bleeding but not with mortality, adverse events, neurosurgical intervention, and rebleeding. More research data is needed on different detection indexes and levels of TXA in patients with TBI, as compared to those not receiving TXA; although the prognostic outcome for all harm outcomes was not affected, the potential for harm was not ruled out.

TRIAL REGISTRATION

The review protocol was registered in the PROSPERO International Prospective Register of Systematic Reviews (CRD42022300484).

Examining four blood biomarkers for the detection of acute intracranial abnormalities following mild traumatic brain injury in older adults

Blood-based biomarkers have been increasingly studied for diagnostic and prognostic purposes in patients with mild traumatic brain injury (MTBI). Biomarker levels in blood have been shown to vary throughout age groups. Our aim was to study four blood biomarkers, glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase-L1 (UCH-L1), neurofilament light (NF-L), and total tau (t-tau), in older adult patients with MTBI. The study sample was collected in the emergency department in Tampere University Hospital, Finland, between November 2015 and November 2016. All consecutive adult patients with head injury were eligible for inclusion. Serum samples were collected from the enrolled patients, which were frozen and later sent for biomarker analyses. Patients aged 60 years or older with MTBI, head computed tomography (CT) imaging, and available biomarker levels were eligible for this study. A total of 83 patients (mean age = 79.0, SD = 9.58, range = 60-100; 41.0% men) were included in the analysis. GFAP was the only biomarker to show statistically significant differentiation between patients with and without acute head CT abnormalities [U₍₈₃₎ = 280, p < 0.001, r = 0.44; area under the curve (AUC) = 0.79, 95% CI = 0.67-0.91]. The median UCH-L1 values were modestly greater in the abnormal head CT group vs. normal head CT group [U ₍₈₃₎ = 492, p = 0.065, r = 0.20; AUC = 0.63, 95% CI = 0.49-0.77]. Older age was associated with biomarker levels in the normal head CT group, with the most prominent age associations being with NF-L (r = 0.56) and GFAP (r = 0.54). The results support the use of GFAP in detecting abnormal head CT findings in older adults with MTBIs. However, small sample sizes run the risk for producing non-replicable findings that may not generalize to the population and do not translate well to clinical use. Further studies should consider the potential effect of age on biomarker levels when establishing clinical cut-off values for detecting head CT abnormalities.

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.

Prognostic value of day-of-injury plasma GFAP and UCH-L1 concentrations for predicting functional recovery after traumatic brain injury in patients from the US TRACK-TBI cohort: an observational cohort study

BACKGROUND

The prognostic value of glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase L1 (UCH-L1) as day-of-injury predictors of functional outcome after traumatic brain injury is not well understood. GFAP is a protein found in glial cells and UCH-L1 is found in neurons, and these biomarkers have been cleared to aid in decision making regarding whether brain CT should be performed after traumatic brain injury. We aimed to quantify their prognostic accuracy and investigate whether these biomarkers contribute novel prognostic information to existing clinical models.

METHODS

We enrolled patients from the Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI) observational cohort study. TRACK-TBI includes patients 17 years and older who are evaluated for TBI at 18 US level 1 trauma centres. All patients receive head CT at evaluation, have adequate visual acuity and hearing preinjury, and are fluent in either English or Spanish. In our analysis, we included participants aged 17-90 years who had day-of-injury plasma samples for measurement of GFAP and UCH-L1 and completed 6-month assessments for outcome due to traumatic brain injury with the Glasgow Outcome Scale-Extended (GOSE-TBI). Biomarkers were analysed as continuous variables and in quintiles. This study is registered with ClinicalTrials.gov, NCT02119182.

FINDINGS

We enrolled 2552 patients from Feb 26, 2014, to Aug 8, 2018. Of the 1696 participants with brain injury and data available at baseline and at 6 months who were included in the analysis, 120 (7·1%) died (GOSE-TBI=1), 235 (13·9%) had an unfavourable outcome (ie, GOSE-TBI ≤4), 1135 (66·9%) had incomplete recovery (ie, GOSE-TBI <8), and 561 (33·1%) recovered fully (ie, GOSE-TBI=8). The area under the curve (AUC) of GFAP for predicting death at 6 months in all patients was 0·87 (95% CI 0·83-0·91), for unfavourable outcome was 0·86 (0·83-0·89), and for incomplete recovery was 0·62 (0·59-0·64). The corresponding AUCs for UCH-L1 were 0·89 (95% CI 0·86-0·92) for predicting death, 0·86 (0·84-0·89) for unfavourable outcome, and 0·61 (0·59-0·64) for incomplete recovery at 6 months. AUCs were higher for participants with traumatic brain injury and Glasgow Coma Scale (GCS) score of 3-12 than for those with GCS score of 13-15. Among participants with GCS score of 3-12 (n=353), adding GFAP and UCH-L1 (alone or combined) to each of the three International Mission for Prognosis and Analysis of Clinical Trials in traumatic brain injury models significantly increased their AUCs for predicting death (AUC range 0·90-0·94) and unfavourable outcome (AUC range 0·83-0·89). However, among participants with GCS score of 13-15 (n=1297), adding GFAP and UCH-L1 to the UPFRONT study model modestly increased the AUC for predicting incomplete recovery (AUC range 0·69-0·69, p=0·025).

INTERPRETATION

In addition to their known diagnostic value, day-of-injury GFAP and UCH-L1 plasma concentrations have good to excellent prognostic value for predicting death and unfavourable outcome, but not for predicting incomplete recovery at 6 months. These biomarkers contribute the most prognostic information for participants presenting with a GCS score of 3-12.

FUNDING

US National Institutes of Health, National Institute of Neurologic Disorders and Stroke, US Department of Defense, One Mind, US Army Medical Research and Development Command.

Development and Validation of a Website to Guide Decision-Making for Disorders of Consciousness

Background

This study aimed to develop and validate a nomogram and present it on a website to be used to predict the overall survival at 16, 32, and 48 months in patients with prolonged disorder of consciousness (pDOC).

Methods

We retrospectively analyzed the data of 381 patients with pDOC at two centers. The data were randomly divided into training and validation sets using a ratio of 6:4. On the training set, Cox proportional hazard analyses were used to identify the predictive variables. In the training set, two models were screened by COX regression analysis, and based on clinical evidence, model 2 was eventually selected in the nomogram after comparing the receiver operating characteristic (ROC) of the two models. In the training and validation sets, ROC curves, calibration curves, and decision curve analysis (DCA) curves were utilized to measure discrimination, calibration, and clinical efficacy, respectively.

Results

The final model included age, Glasgow coma scale (GCS) score, serum albumin level, and computed tomography (CT) midline shift, all of which had a significant effect on survival after DOCs. For the 16-, 32-, and 48-month survival on the training set, the model had good discriminative power, with areas under the curve (AUCs) of 0.791, 0.760, and 0.886, respectively. For the validation set, the AUCs for the 16-, 32-, and 48-month survival predictions were 0.806, 0.789, and 0.867, respectively. Model performance was good for both the training and validation sets according to calibration plots and DCA.

Conclusion

We developed an accurate, efficient nomogram, and a corresponding website based on four correlated factors to help clinicians improve their assessment of patient outcomes and help personalize the treatment process and clinical decisions.

Early dynamics of glial fibrillary acidic protein and extracellular DNA in plasma of mice after closed head traumatic brain injury

BACKGROUND

Glial fibrillary acidic protein (GFAP) in plasma is an established biomarker of traumatic brain injury (TBI) in humans. Plasma extracellular DNA (ecDNA) is a very sensitive, although nonspecific marker of tissue damage including TBI. Whether plasma GFAP or ecDNA could be used as an early non-invasive biomarker in the mouse model of closed head injury is unknown. The aim of this paper was to describe the early dynamics of plasma GFAP and ecDNA in the animal model of closed head TBI.

METHODS

Closed head TBI was induced using the weight-drop method in 40 adult CD1 mice and blood was collected in different time points (1, 2 or 3h) after TBI in different groups of mice. Plasma GFAP and ecDNA and ecDNA fragmentation from the experimental groups were compared to healthy controls. In the surviving mice, a static rods test was performed 30 days after TBI to assess the neurological outcome of TBI.

RESULTS

Despite a trend of higher plasma GFAP after TBI the differences between the groups were not statistically significant. Plasma ecDNA was higher by 50% after 1h (P<0.05) and 2h (P<0.05) after TBI and was highly variable after 3h. Plasma ecDNA, but not GFAP, was partially predictive of the neurological impairment of the mice.

CONCLUSION

In this study, we have described the early dynamics of plasma GFAP and ecDNA after TBI in mice. According to our results, ecDNA in plasma is a more sensitive early marker of TBI than GFAP. Analysis of tissue-specific ecDNA might improve its predictive value regarding the survival and neurobehavioral outcome.

Serum NOX4 as a Promising Prognostic Biomarker in Association with 90-Day Outcome of Severe Traumatic Brain Injury

Purpose

Nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) is related to brain oxidative stress. We attempted to examine the association between serum NOX4 levels, severity and prognosis of severe traumatic brain injury (sTBI).

Methods

We measured serum NOX4 levels in 105 patients with sTBI. Trauma severity was assessed using Glasgow coma scale (GCS) and Rotterdam computed tomography (CT) classification. Study outcome data on death and worst outcome (Glasgow outcome scale score of 1-3) were collected at 90 days after trauma. Multivariate analyses were performed to determine independent factors for overall survival and worst outcome. Area under receiver operating characteristic curve (AUC) was estimated to assess prognostic predictive ability.

Results

Serum NOX4 levels were tightly correlated with GCS score (t=-5.843, P < 0.001) and Rotterdam CT score (t = 4.231, P < 0.001). During 90 days of follow-up, 50 participants (47.6%) experienced a worse outcome, 28 (26.7%) died and the mean overall survival time was 71.9 days (95% confidence interval (CI), 65.7-78.1 days). Serum NOX4 was independently associated with an increased risk of short overall survival (hazard ratio, 1.129; 95% CI, 1.039-1.228) or worse outcome (odds ratio, 1.053; 95% CI, 1.014-1.095). Serum NOX4 levels had a certain predictive value for the patient's risk of mortality (AUC, 0.803; 95% CI, 0.714-0.874) or worse outcome (AUC, 0.780; 95% CI, 0.689-0.855). Moreover, its AUC was in the range of GCS score and Rotterdam CT score (both P > 0.05) and it significantly improved their AUCs (both P < 0.05).

Conclusion

Serum NOX4 levels in the acute phase of sTBI were associated with trauma severity, an increased risk of mortality and worse outcome, suggesting that serum NOX4 could be an important prognostic factor for sTBI.

Development of an electrochemical impedance spectroscopy based biosensor for detection of ubiquitin C-Terminal hydrolase L1

Year over year, the incidence of traumatic brain injury (TBI) in the population is dramatically increasing; thus, timely diagnosis is crucial for improving patient outcomes in the clinic. Ubiquitin C-terminal hydrolase L1 (UCH-L1), a blood-based biomarker, has been approved by the FDA as a promising quantitative indicator of mild TBI that arises in blood serum shortly after injury. Current gold standard techniques for its quantitation are time-consuming and require specific laboratory equipment. Hence, development of a hand-held device is an attractive alternative. In this study, we report a novel system for rapid, one-step electrochemical UCH-L1 detection. Electrodes were functionalized with anti-UCH-L1 antibody, which was used as a molecular recognition element for selective sensing of UCH-L1. Electrochemical impedance spectroscopy (EIS) was used as a transduction method to quantify its binding. When the electrode was incubated with different concentrations of UCH-L1, impedance signal increased against a concentration gradient with high logarithmic correlation. Upon single-frequency analysis, a second calibration curve with greater signal to noise was obtained, which was used to distinguish physiologically relevant concentrations of UCH-L1. Notably, our system could detect UCH-L1 within 5 min, without a washing step nor bound/free separation, and had resolution across concentrations ranging from 1 pM to 1000 pM within an artificial serum sample. These attributes, together with the miniaturization potential afforded by an impedimetric sensing platform, make this platform an attractive candidate for scale-up as a device for rapid, on-site detection of TBI. These findings may aid in the future development of sensing systems for quantitative TBI detection.

Brain Injury Biomarkers for Predicting Outcome After Cardiac Arrest

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2022. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2022 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from https://link.springer.com/bookseries/8901 .

Vibrational spectroscopy for the triage of traumatic brain injury CT priority and hospital admissions

Computed Tomogram (CT) brain imaging is routinely used to support clinical decision-making in patients with traumatic brain injury (TBI). However, only 7% of scans demonstrate evidence of TBI. The other 93% of scans contribute a significant cost to the healthcare system and a radiation risk to patients. There may be better strategies to identify which patients, particularly those with mild TBI, are at risk of deterioration and require hospital admission. We introduce a blood serum liquid biopsy that utilises attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) spectroscopy with machine learning algorithms as a decision-making tool to identify which mild TBI patients will most benefit from CT brain imaging. Serum samples were obtained from (n=298) patients who had acquired a TBI and were enrolled in CENTER-TBI, and from asymptomatic control patients (n=87). Injury patients (all severities) were stratified against non-injury controls. The mild TBI cohort was further examined by stratifying those who had at least one CT abnormality against those who had no CT abnormalities. The test performed exceptionally well in classifications of mild injury patients versus non-injury controls (sensitivity = 96.4% and specificity = 98.0%) and also provided a sensitivity of 80.2% when stratifying mild patients with at least one CT abnormality against those without. The results provided illustrate the test ability to identify 4 out of every 5 CT abnormalities and shows great promise to be introduced as a triage tool for CT priority in mild TBI patients.

Blood GFAP as an emerging biomarker in brain and spinal cord disorders

Blood-derived biomarkers for brain and spinal cord diseases are urgently needed. The introduction of highly sensitive immunoassays led to a rapid increase in the number of potential blood-derived biomarkers for diagnosis and monitoring of neurological disorders. In 2018, the FDA authorized a blood test for clinical use in the evaluation of mild traumatic brain injury (TBI). The test measures levels of the astrocytic intermediate filament glial fibrillary acidic protein (GFAP) and neuroaxonal marker ubiquitin carboxy-terminal hydrolase L1. In TBI, blood GFAP levels are correlated with clinical severity and extent of intracranial pathology. Evidence also indicates that blood GFAP levels hold the potential to reflect, and might enable prediction of, worsening of disability in individuals with progressive multiple sclerosis. A growing body of evidence suggests that blood GFAP levels can be used to detect even subtle injury to the CNS. Most importantly, the successful completion of the ongoing validation of point-of-care platforms for blood GFAP might ameliorate the decision algorithms for acute neurological diseases, such as TBI and stroke, with important economic implications. In this Review, we provide a systematic overview of the evidence regarding the utility of blood GFAP as a biomarker in neurological diseases. We propose a model for GFAP concentration dynamics in different conditions and discuss the limitations that hamper the widespread use of GFAP in the clinical setting. In our opinion, the clinical use of blood GFAP measurements has the potential to contribute to accelerated diagnosis and improved prognostication, and represents an important step forward in the era of precision medicine.

A dynamic model to predict long-term outcomes in patients with prolonged disorders of consciousness

PURPOSE

It is important to predict the prognosis of patients with prolonged disorders of consciousness (DOC). This study established and validated a nomogram and corresponding web-based calculator to predict outcomes for patients with prolonged DOC.

METHODS

All data were obtained from the First Affiliated Hospital of Nanchang University and the Shangrao Hospital of Traditional Chinese Medicine. Predictive variables were identified by univariate and multiple logistic regression analyses. Receiver operating characteristic curves, calibration curves, and a decision curve analysis (DCA) were utilized to assess the predictive accuracy, discriminative ability, and clinical utility of the model, respectively.

RESULTS

Independent prognostic factors, such as age, Glasgow coma scale score, state of consciousness, and brainstem auditory-evoked potential grade were integrated into a nomogram. The model demonstrated good discrimination in the training and validation cohorts, with area-under-the-curve values of 0.815 (95% confidence interval [CI]: 0.748-0.882) and 0.805 (95% CI: 0.727-0.883), respectively. The calibration plots and DCA demonstrated good model performance and clear clinical benefits in both cohorts.

CONCLUSIONS

Based on our nomogram, we developed an effective, simple, and accurate model of a web-based calculator that may help individualize healthcare decision-making. Further research is warranted to optimize the system and update the predictors.

A predictive model for postoperative progressive haemorrhagic injury in traumatic brain injuries

Background

Progressive haemorrhagic injury after surgery in patients with traumatic brain injury often results in poor patient outcomes. This study aimed to develop and validate a practical predictive tool that can reliably estimate the risk of postoperative progressive haemorrhagic injury (PHI) in patients with traumatic brain injury (TBI).

Methods

Data from 645 patients who underwent surgery for TBI between March 2018 and December 2020 were collected. The outcome was postoperative intracranial PHI, which was assessed on postoperative computed tomography. The least absolute shrinkage and selection operator (LASSO) regression model, univariate analysis, and Delphi method were applied to select the most relevant prognostic predictors. We combined conventional coagulation test (CCT) data, thromboelastography (TEG) variables, and several predictors to develop a predictive model using binary logistic regression and then presented the results as a nomogram. The predictive performance of the model was assessed with calibration and discrimination. Internal validation was assessed.

Results

The signature, which consisted of 11 selected features, was significantly associated with intracranial PHI (p < 0.05, for both primary and validation cohorts). Predictors in the prediction nomogram included age, S-pressure, D-pressure, pulse, temperature, reaction time, PLT, prothrombin time, activated partial thromboplastin time, FIB, and kinetics values. The model showed good discrimination, with an area under the curve of 0.8694 (95% CI, 0.8083–0.9304), and good calibration.

Conclusion

This model is based on a nomogram incorporating CCT and TEG variables, which can be conveniently derived at hospital admission. It allows determination of this individual risk for postoperative intracranial PHI and will facilitate a timely intervention to improve outcomes.

Extracellular Vesicle Levels of Nervous System Injury Biomarkers in Critically Ill Trauma Patients with and without Traumatic Brain Injury

Moderate/severe traumatic brain injury (TBI) causes injury patterns with heterogeneous pathology producing varying outcomes for recovery. Extracellular vesicles (EVs) are particles containing a myriad of molecules involved in cell signaling. EVs may hold promise as biomarkers in TBI because of their encapsulation, including improved stability/decreased degradation. A subset of subjects with and without TBI from a prospective, observational trial of critically ill trauma patients were analyzed. Total EV levels of glial (glial fibrillary acidic protein; GFAP) and neuronal/axonal (ubiquitin carboxy-terminal hydrolase L1 [UCH-L1], neurofilament light chain [NfL], and total-tau) proteins were measured using single-molecule array technology. Protein levels were winsorized to address outliers and log transformed for analysis. Patients with multiple injuries (n = 41) and isolated body injury (n = 73) were of similar age and sex. Patients with multiple injuries were, as expected, more severely injured with higher Injury Severity Scores (29 [26-41] vs. 21 [14-26], p < 0.001) and lower Glasgow Coma Scale scores (12 [4-13] vs. 13 [13-13], p < 0.001). Total body EVs of GFAP, UCH-L1, and NfL were higher in those with multiple injuries (1768 [932-4780] vs. 239 [63-589], p < 0.001; 75.4 [47.8-158.3] vs. 41.5 [21.5-67.1], p = 0.03; 7.5 [3.3-12.3] vs. 2.9 [2.1-4.8], p < 0.001, respectively). There was a moderate correlation between the Head Abbreviated Injury Score and GFAP (free circulating rho = 0.62, EV rho = 0.64; both p < 0.001). Brain-derived proteins contained in EV holds promise as an informative approach to biomarker measurement after TBI in hospitalized patients. Future evaluation and longitudinal studies are necessary to draw conclusions regarding the clinical utility of these biomarkers.