Performance of glial fibrillary acidic protein (GFAP) and ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) biomarkers in predicting CT scan results and neurological outcomes in children with traumatic brain injury (BRAINI-2 paediatric study): protocol of a European prospective multicentre study.

INTRODUCTION: In light of the burden of traumatic brain injury (TBI) in children and the excessive number of unnecessary CT scans still being performed, new strategies are needed to limit their use while minimising the risk of delayed diagnosis of intracranial lesions (ICLs). Identifying children at higher risk of poor outcomes would enable them to be better monitored. The use of the blood-based brain biomarkers glial fibrillar acidic protein (GFAP) and ubiquitin carboxy-terminal hydrolase-L1 (UCH-L1) could help clinicians in this decision. The overall aim of this study is to provide new knowledge regarding GFAP and UCH-L1 in order to improve TBI management in the paediatric population. METHODS AND ANALYSIS: We will conduct a European, prospective, multicentre study, the BRAINI-2 paediatric study, in 20 centres in France, Spain and Switzerland with an inclusion period of 30 months for a total of 2880 children and adolescents included. To assess the performance of GFAP and UCH-L1 used separately and in combination to predict ICLs on CT scans (primary objective), 630 children less than 18 years of age with mild TBI, defined by a Glasgow Coma Scale score of 13-15 and with a CT scan will be recruited. To evaluate the potential of GFAP and UCH-L1 in predicting the prognosis after TBI (secondary objective), a further 1720 children with mild TBI but no CT scan as well as 130 children with moderate or severe TBI will be recruited. Finally, to establish age-specific reference values for GFAP and UCH-L1 (secondary objective), we will include 400 children and adolescents with no history of TBI. ETHICS AND DISSEMINATION: This study has received ethics approval in all participating countries. Results from our study will be disseminated in international peer-reviewed journals. All procedures were developed in order to assure data protection and confidentiality. TRIAL REGISTRATION NUMBER: NCT05413499.

Comparison of GFAP and UCH-L1 Measurements Using Two Automated Immunoassays (i-STAT® and Alinity®) for the Management of Patients with Mild Traumatic Brain Injury: Preliminary Results from a French Single-Center Approach.

The measurement of blood glial fibrillary acidic protein (GFAP) and ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) may assist in the management of mild traumatic brain injury (mTBI). This study aims to compare GFAP and UCH-L1 values measured using a handheld device with those measured using a core laboratory platform. We enrolled 230 mTBI patients at intermediate risk of complications. Following French guidelines, a negative S100B value permits the patient to be discharged without a computed tomography scan. Plasma GFAP and UCH-L1 levels were retrospectively measured using i-STAT® and Alinity® i analyzers in patients managed within 12 h post-trauma. Our analysis indicates a strong correlation of biomarker measurements between the two analyzers. Cohen's kappa coefficients and Lin's concordance coefficients were both ≥0.7, while Spearman's correlation coefficient was 0.94 for GFAP and 0.90 for UCH-L1. Additionally, the diagnostic performance in identifying an intracranial lesion was not significantly different between the two analyzers, with a sensitivity of 100% and specificity of approximately 30%. GFAP and UCH-L1 levels measured using Abbott's i-STAT® and Alinity® i platform assays are highly correlated both analytically and clinically in a cohort of 230 patients managed for mTBI according to French guidelines.

Investigation of Early Diagnostic Value of Glial Fibrillary Acidic Protein and Ubiquitin C-Terminal Hydrolase Blood Levels in Minor Head Trauma in Turkey.

BACKGROUND: The aim was to investigate the early diagnostic value of serum glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase (UCH-L1) levels in adults with minor head trauma (MHT) and whether it could be an alternative diagnostic method to computed tomography (CT). This is the first study with the combination of GFAP and UCH-L1 in the first 3 hours of MHT. METHODS: The study comprised 88 patients, 60 patients and 28 controls, who were evaluated as having MHT, were admitted to the emergency department of our hospital within the first 3 hours of the trauma and met the inclusion criteria. CT was performed on all patients. Serum GFAP and UCH-L1 levels were measured within the first 3 hours of the trauma. RESULTS: The median serum GFAP level was 1.07 ng/mL in the group with pathology on CT and 0.42 ng/mL in the group with no pathology on CT. The median serum UCH-L1 level was 0.40 ng/mL in the group with pathology on CT and 0.39 ng/mL in the group with no pathology on CT. A statistically significant difference was found between the serum GFAP levels of the CT (+) group and the CT (-) group (p = 0.021). GFAP levels were compared according to the CT (+) and CT (-) groups with a cutoff value of ≥ 1.56 ng/mL for GFAP, which had 50% sensitivity and 97.5% specificity. This was statistically significant (p = 0.008). It was found that the UCH-L1 level of the control group was lower than the UCH-L1 levels of the CT (+) and CT (-) groups, and this difference was found to be statistically significant (p = 0.003 and p = 0.018, respectively). CONCLUSIONS: GFAP was found to be more specific than UCH-L1 in demonstrating the presence of intracranial pathology in patients with head trauma who were admitted to the emergency department in the first 3 hours after trauma.

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.

Ubiquitin carboxyl-terminal esterase L1 is not elevated in the serum of concussed rugby players: an observational cross-sectional study.

Concussion diagnosis is complicated by a lack of objective measures. Ubiquitin carboxyl-terminal esterase L1 (UCHL1) is a biomarker that has been shown to increase following traumatic brain injury but has not been investigated in concussed athletes on the sideline of athletic events. Therefore, this study was conducted to determine if UCHL1 can be used to aid in sideline concussion diagnosis. Blood was taken via standard venipuncture from a recreationally active control group, a group of rugby players prior to match play (pre-match), rugby players following match-play (match-control), and rugby players after suffering a sport-related concussion (SRC). UCHL1 was not significantly different among groups (p > 0.05) and was unable to distinguish between SRC and controls (AUROC < 0.400, p > 0.05). However, when sex-matched data were used, it was found that the female match-control group had a significantly higher serum UCHL1 concentration than the pre-match group (p = 0.041). Differences were also found in serum UCHL1 concentrations between male and female athletes in the match-control group (p = 0.007). This study does not provide evidence supporting the use of UCHL1 in sideline concussion diagnosis when blood is collected soon after concussion but does show differences in serum UCHL1 accumulation between males and females.

Association of Ubiquitin C-Terminal Hydrolase-L1 (Uch-L1) serum levels with cognition and brain energy metabolism.

OBJECTIVE: In recent years, many researchers have taken serum ubiquitin c-terminal hydrolase (Uch-L1) as an indicator of post-traumatic brain injury and associated it with cognitive impairment. Alzheimer's disease is characterized by cognitive impairment and energy metabolism disorders. The purpose of this study was to detect whether serum Uch-L1 is related to cognition and brain energy metabolism in healthy people, and to explore whether it can be used as an early blood marker of Alzheimer's disease. PATIENTS AND METHODS: In this prospective cohort study, adult outpatients from a Grade 3A hospital were recruited. They completed the 18F-FDG-PET/CT examination in the nuclear medicine department and were screened by the Mini Mental State scale (MMSE) and the Montreal Cognitive Assessment scale (MoCA). Blood samples were collected from all outpatients to detect the concentration of serum Uch-L1, and the mean standard uptake value (SUVmean) of energy metabolism in the hippocampus during PET/CT examination was collected. RESULTS: A total of 37 participants, 14 participants with cognitive impairment (MMSE score < 27) and 23 controls (MMSE score 27-30) were included. There was a significant difference in the SUVmean of the hippocampus between the cognitive impairment group and the normal control group (p < 0.05). There was a significant correlation between the SUVmean of the hippocampus and the total score of MMSE in all participants [r = 0.439, 95% CI: (0.139-0.668), p = 0.007]. There were also significant correlations between serum Uch-L1 and MMSE. Based on the significant differences of demographic variables between groups, we conducted a multivariate linear regression analysis of MMSE cognitive scores based on age (X1), length of education (X2) and SUVmean of hippocampus (X3). The regression equation is as follows: Y = 25.709-0.072 X1 + 0.422 X2 + 0.232 X3. CONCLUSIONS: Brain cognitive ability is closely related to energy metabolism and serum Uch-L1 concentration, so serum Uch-L1 may become a blood marker for extensive screening of dementia in the future. We look forward to the introduction of a more accurate and low-cost method for detecting serum Uch-L1 concentration.

Clinical and Pathological Correlations in Chronic Venous Disease.

BACKGROUND: Chronic Venous Disease (CVD) has a high prevalence in the western world. Varicose veins (VVs) are the main signs of this disease that is characterized by important pathological vessel wall changes. The aim of this study is to correlate the main histopathological abnormalities with related clinical issues of CVD. METHODS: A cohort of patients with VVs scheduled for open surgical treatment namely stab avulsion of VVs was recruited. Subsequently, venous tissue from stab avulsion was collected in order to evaluate the following biomarkers: Vascular-Endothelial Growth Factor (VEGF), Protein Gene Product 9.5 (PGP 9.5), Fibronectin (FN), and Matrix Metalloproteinase-9 (MMP-9). The Clinical-Etiology-Anatomy-Pathophysiology (CEAP) criteria were used to classify CVD. RESULTS: Fourteen tissue fragments were processed for histological and immunohistochemical studies. Of these, 43% were from CEAP C2 patients, 36% from CEAP C3 patients, and 21% from CEAP C4 patients. CEAP Class C2 had few to moderate structures positive to VEGF; occasional structures positive to Fibronectin, numerous structures positive to MMP9, few to moderate structures positive to PGP 9.5. CEAP Class C3 had moderate structures positive to VEGF; few to moderate structures positive to Fibronectin; many structures positive to MMP9; few to moderate structures positive to PGP 9.5. CEAP Class C4 had numerous structures positive to VEGF; numerous structures positive to Fibronectin; abundant structures positive to MMP-9; few structures positive to PGP 9.5. CONCLUSIONS: In this study, positive VEGF, FN, and MMP-9 structures were found with increasing trends in relation to the disease staging. VEGF and FN are associated with a progressive increase from C2 to C4. The MMP-9 marker has an important positivity even at early stage of the disease, being higher in CEAP C4 patients. PGP 9.5 decreases in CEAP C4 patients and this is concordant to decreased vein wall innervation.

Brain Hypoxia Is Associated With Neuroglial Injury in Humans Post-Cardiac Arrest.

[Figure: see text].

Transient siRNA-mediated protein knockdown in mouse followed by feeding/starving cycle and liver tissue analysis.

We present a protocol for in vivo siRNA-mediated knockdown of a gene of interest in mouse liver using systemic delivery via intravenous injection. We describe a step-by-step protocol for delivery of siRNA particles, with tips on how to optimize dosage. We detail steps for feeding/starving cycles as well as for liver tissue isolation, followed by gene expression analysis, measured at the mRNA and protein levels. For complete information on the generation and use of this protocol, please refer to Wrobel et al. (2020).

Blood neurofilament light chain and total tau levels at admission predict death in COVID-19 patients.

BACKGROUND AND AIMS: Patients infected with SARS-CoV-2 range from asymptomatic, to mild, moderate or severe disease evolution including fatal outcome. Thus, early predictors of clinical outcome are highly needed. We investigated markers of neural tissue damage as a possible early sign of multisystem involvement to assess their clinical prognostic value on survival or transfer to intensive care unit (ICU). METHODS: We collected blood from 104 patients infected with SARS-CoV-2 the day of admission to the emergency room and measured blood neurofilament light chair (NfL), glial fibrillary acidic protein (GFAP), ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), and total tau protein levels. RESULTS: We found that NfL, GFAP, and tau were significantly increased in patients with fatal outcome, while NfL and UCH-L1 in those needing ICU transfer. ROC and Kaplan-Meier curves indicated that total tau levels at admission accurately predict mortality. CONCLUSIONS: Blood neural markers may provide additional prognostic value to conventional biomarkers used to predict COVID-19 outcome.

Neurotrauma Biomarker Levels and Adverse Symptoms Among Military and Law Enforcement Personnel Exposed to Occupational Overpressure Without Diagnosed Traumatic Brain Injury.

Importance: There is a scientific and operational need to define objective measures of exposure to low-level overpressure (LLOP) and concussion-like symptoms among persons with specialized occupations. Objective: To evaluate serum levels of neurotrauma biomarkers and their association with concussion-like symptoms reported by LLOP-exposed military and law enforcement personnel who are outwardly healthy and cleared to perform duties. Design, Setting, and Participants: This retrospective cohort study, conducted from January 23, 2017, to October 21, 2019, used serum samples and survey data collected from healthy, male, active-duty military and law enforcement personnel assigned to operational training at 4 US Department of Defense and civilian law enforcement training sites. Personnel aged 18 years or older with prior LLOP exposure but no diagnosed traumatic brain injury or with acute blast exposure during sampling participated in the study. Serum samples from 30 control individuals were obtained from a commercial vendor. Main Outcomes and Measures: Serum levels of glial fibrillary acidic protein, ubiquitin carboxyl hydrolase (UCH)-L1, neurofilament light chain, tau, amyloid ß (Aß)-40, and Aß-42 from a random sample (30 participants) of the LLOP-exposed cohort were compared with those of 30 age-matched controls. Associations between biomarker levels and self-reported symptoms or operational demographics in the remainder of the study cohort (76 participants) were assessed using generalized linear modeling or Spearman correlations with age as a covariate. Results: Among the 30 randomly sampled participants (mean [SD] age, 32 [7.75] years), serum levels of UCH-L1 (mean difference, 4.92; 95% CI, 0.71-9.14), tau (mean difference, 0.16; 95% CI, -0.06 to 0.39), Aß-40 (mean difference, 138.44; 95% CI, 116.32-160.56), and Aß-42 (mean difference, 4.97; 95% CI, 4.10-5.83) were elevated compared with those in controls. Among the remaining cohort of 76 participants (mean [SD] age, 34 [7.43] years), ear ringing was reported by 44 (58%) and memory or sleep problems were reported by 24 (32%) and 20 (26%), respectively. A total of 26 participants (34%) reported prior concussion. Amyloid ß-42 levels were associated with ear ringing (F1,72 = 7.40; P = .008) and memory problems (F1,72 = 9.20; P = .003). Conclusions and Relevance: The findings suggest that long-term LLOP exposure acquired during occupational training may be associated with serum levels of neurotrauma biomarkers. Assessment of biomarkers and concussion-like symptoms among personnel considered healthy at the time of sampling may be useful for military occupational medicine risk management.

Serum Neuron-Specific Enolase Levels Associated with Connectivity Alterations in Anterior Default Mode Network after Mild Traumatic Brain Injury.

Mild traumatic brain injury (mTBI) is the most prevalent neurological insult and leads to long-lasting cognitive impairment. Neuroimaging studies have discovered abnormalities in brain network connectivity following mTBI as the underlying neural basis of cognitive deficits. However, the pathophysiologic mechanisms involved in imaging alterations remain elusive. Proteins neuron-specific enolase (NSE) and ubiquitin C terminal hydrolase 1 are reliable markers for neuronal cell-body damage, both of which have been demonstrated to be increased in serum following mTBI. Therefore, we conducted a longitudinal study to examine relationships between abnormal brain network connectivity and serum neuronal biomarkers and their associations with cognitive recovery following mTBI. Sixty patients were followed-up at 1 week and 3 months post-injury and 41 controls were recruited. Resting-state functional magnetic resonance imaging was used to build a functional connectivity matrix within large-scale intrinsic networks, and their topological properties were analyzed using graph theory measures. We found that, compared with controls, mTBI patients showed significant decreases in a number of nodal characteristics in default mode network (DMN), salience network, and executive network (p < 0.05, false discovery rate corrected) at 3 months post-injury. Linear regression analysis found elevated serum NSE in acute phase could predict lower efficiency and degree centrality of anterior DMN at 3 months post-injury. In addition, efficiency and degree centrality of anterior DMN were negatively associated with working memory. Our study showed neuronal injury was associated with alterations in brain network connectivity after mTBI. These findings can facilitate capability to predict the brain functional outcomes and cognitive recovery in mTBI.

Assessment of Blood Biomarker Profile After Acute Concussion During Combative Training Among US Military Cadets: A Prospective Study From the NCAA and US Department of Defense CARE Consortium.

Importance: Validation of protein biomarkers for concussion diagnosis and management in military combative training is important, as these injuries occur outside of traditional health care settings and are generally difficult to diagnose. Objective: To investigate acute blood protein levels in military cadets after combative training-associated concussions. Design, Setting, and Participants: This multicenter prospective case-control study was part of a larger cohort study conducted by the National Collegiate Athletic Association and the US Department of Defense Concussion Assessment Research and Education (CARE) Consortium from February 20, 2015, to May 31, 2018. The study was performed among cadets from 2 CARE Consortium Advanced Research Core sites: the US Military Academy at West Point and the US Air Force Academy. Cadets who incurred concussions during combative training (concussion group) were compared with cadets who participated in the same combative training exercises but did not incur concussions (contact-control group). Clinical measures and blood sample collection occurred at baseline, the acute postinjury point (<6 hours), the 24- to 48-hour postinjury point, the asymptomatic postinjury point (defined as the point at which the cadet reported being asymptomatic and began the return-to-activity protocol), and 7 days after return to activity. Biomarker levels and estimated mean differences in biomarker levels were natural log (ln) transformed to decrease the skewness of their distributions. Data were collected from August 1, 2016, to May 31, 2018, and analyses were conducted from March 1, 2019, to January 14, 2020. Exposure: Concussion incurred during combative training. Main Outcomes and Measures: Proteins examined included glial fibrillary acidic protein, ubiquitin C-terminal hydrolase-L1, neurofilament light chain, and tau. Quantification was conducted using a multiplex assay (Simoa; Quanterix Corp). Clinical measures included the Sport Concussion Assessment Tool-Third Edition symptom severity evaluation, the Standardized Assessment of Concussion, the Balance Error Scoring System, and the 18-item Brief Symptom Inventory. Results: Among 103 military service academy cadets, 67 cadets incurred concussions during combative training, and 36 matched cadets who engaged in the same training exercises did not incur concussions. The mean (SD) age of cadets in the concussion group was 18.6 (1.3) years, and 40 cadets (59.7%) were male. The mean (SD) age of matched cadets in the contact-control group was 19.5 (1.3) years, and 25 cadets (69.4%) were male. Compared with cadets in the contact-control group, those in the concussion group had significant increases in glial fibrillary acidic protein (mean difference in ln values, 0.34; 95% CI, 0.18-0.50; P < .001) and ubiquitin C-terminal hydrolase-L1 (mean difference in ln values, 0.97; 95% CI, 0.44-1.50; P < .001) levels at the acute postinjury point. The glial fibrillary acidic protein level remained high in the concussion group compared with the contact-control group at the 24- to 48-hour postinjury point (mean difference in ln values, 0.22; 95% CI, 0.06-0.38; P = .007) and the asymptomatic postinjury point (mean difference in ln values, 0.21; 95% CI, 0.05-0.36; P = .01). The area under the curve for all biomarkers combined, which was used to differentiate cadets in the concussion and contact-control groups, was 0.80 (95% CI, 0.68-0.93; P < .001) at the acute postinjury point. Conclusions and Relevance: This study's findings indicate that blood biomarkers have potential for use as research tools to better understand the pathobiological changes associated with concussion and to assist with injury identification and recovery from combative training-associated concussions among military service academy cadets. These results extend the previous findings of studies of collegiate athletes with sport-associated concussions.

Characterization of Cerebrospinal Fluid Ubiquitin C-Terminal Hydrolase L1 as a Biomarker of Human Acute Traumatic Spinal Cord Injury.

A major obstacle for translational research in acute spinal cord injury (SCI) is the lack of biomarkers that can objectively stratify injury severity and predict outcome. Ubiquitin C-terminal hydrolase L1 (UCH-L1) is a neuron-specific enzyme that shows promise as a diagnostic biomarker in traumatic brain injury (TBI), but has not been studied in SCI. In this study, cerebrospinal fluid (CSF) and serum samples were collected over the first 72-96 h post-injury from 32 acute SCI patients who were followed prospectively to determine neurological outcomes at 6 months post-injury. UCH-L1 concentration was measured using the Quanterix Simoa platform (Quanterix, Billerica, MA) and correlated to injury severity, time, and neurological recovery. We found that CSF UCH-L1 was significantly elevated by 10- to 100-fold over laminectomy controls in an injury severity- and time-dependent manner. Twenty-four-hour post-injury CSF UCH-L1 concentrations distinguished between American Spinal Injury Association Impairment Scale (AIS) A and AIS B, and AIS A and AIS C patients in the acute setting, and predicted who would remain "motor complete" (AIS A/B) at 6 months with a sensitivity of 100% and a specificity of 86%. AIS A patients who did not improve their AIS grade at 6 months post-injury were characterized by sustained elevations in CSF UCH-L1 up to 96 h. Similarly, the failure to gain >8 points on the total motor score at 6 months post-injury was associated with higher 24-h CSF UCH-L1. Unfortunately, serum UCH-L1 levels were not informative about injury severity or outcome. In conclusion, CSF UCH-L1 in acute SCI shows promise as a biomarker to reflect injury severity and predict outcome.

Progesterone Treatment Does Not Decrease Serum Levels of Biomarkers of Glial and Neuronal Cell Injury in Moderate and Severe Traumatic Brain Injury Subjects: A Secondary Analysis of the Progesterone for Traumatic Brain Injury, Experimental Clinical Treatment (ProTECT) III Trial.

Early treatment of moderate/severe traumatic brain injury (TBI) with progesterone does not improve clinical outcomes. This is in contrast with findings from pre-clinical studies of progesterone in TBI. To understand the reasons for the negative clinical trial, we investigated whether progesterone treatment has the desired biological effect of decreasing brain cell death. We quantified brain cell death using serum levels of biomarkers of glial and neuronal cell death (glial fibrillary acidic protein [GFAP], ubiquitin carboxy-terminal hydrolase-L1 [UCH-L1], S100 calcium-binding protein B [S100B], and Alpha II Spectrin Breakdown Product 150 [SBDP]) in the Biomarkers of Injury and Outcome-Progesterone for Traumatic Brain Injury, Experimental Clinical Treatment (BIO-ProTECT) study. Serum levels of GFAP, UCHL1, S100B, and SBDP were measured at baseline (≤4 h post-injury and before administration of study drug) and at 24 and 48 h post-injury. Serum progesterone levels were measured at 24 and 48 h post-injury. The primary outcome of ProTECT was based on the Glasgow Outcome Scale-Extended assessed at 6 months post-randomization. We found that at baseline, there were no differences in biomarker levels between subjects randomized to progesterone treatment and those randomized to placebo (p > 0.10). Similarly, at 24 and 48 h post-injury, there were no differences in biomarker levels in the progesterone versus placebo groups (p > 0.15). There was no statistically significant correlation between serum progesterone concentrations and biomarker values obtained at 24 and 48 h. When examined as a continuous variable, baseline biomarker levels did not modify the association between progesterone treatment and neurological outcome (p of interaction term >0.39 for all biomarkers). We conclude that progesterone treatment does not decrease levels of biomarkers of glial and neuronal cell death during the first 48 h post-injury.

Blood Biomarkers Relate to Cognitive Performance Years after Traumatic Brain Injury in Service Members and Veterans.

OBJECTIVE: This study examines the relationship of serum total tau, neurofilament light (NFL), ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1), and glial fibrillary acidic protein (GFAP) with neurocognitive performance in service members and veterans with a history of traumatic brain injury (TBI). METHOD: Service members (n = 488) with a history of uncomplicated mild (n = 172), complicated mild, moderate, severe, or penetrating TBI (sTBI; n = 126), injured controls (n = 116), and non-injured controls (n = 74) prospectively enrolled from Military Treatment Facilities. Participants completed a blood draw and neuropsychological assessment a year or more post-injury. Six neuropsychological composite scores and presence/absence of mild neurocognitive disorder (MNCD) were evaluated. Within each group, stepwise hierarchical regression models were conducted. RESULTS: Within the sTBI group, increased serum UCH-L1 was related to worse immediate memory and delayed memory (R2Δ = .065-.084, ps < .05) performance, while increased GFAP was related to worse perceptual reasoning (R2Δ = .030, p = .036). Unexpectedly, within injured controls, UCH-L1 and GFAP were inversely related to working memory (R2Δ = .052-.071, ps < .05), and NFL was related to executive functioning (R2Δ = .039, p = .021) and MNCD (Exp(B) = 1.119, p = .029). CONCLUSIONS: Results suggest GFAP and UCH-L1 could play a role in predicting poor cognitive outcome following complicated mild and more severe TBI. Further investigation of blood biomarkers and cognition is warranted.

Evaluation of ubiquitin C-terminal hydrolase-L1 enzyme levels in patients with epilepsy.

OBJECTIVE: Ubiquitin C-terminal Hydrolase-L1 (UCH-L1) enzyme levels were investigated in patients with epilepsy, epileptic seizure, remission period, and healthy individuals. METHODS: Three main groups were evaluated, including epileptic seizure, patients with epilepsy in the non-seizure period, and healthy volunteers. The patients having a seizure in the Emergency department or brought by a postictal confusion were included in the epileptic attack group. The patients having a seizure attack or presenting to the Neurology outpatient department for follow up were included in the non-seizure (remission period) group. RESULTS: The UCH-L1 enzyme levels of 160 patients with epilepsy (80 patients with epileptic attack and 80 patients with epilepsy in the non-seizure period) and 100 healthy volunteers were compared. Whereas the UCH-L1 enzyme levels were 8.30 (IQR=6.57‒11.40) ng/mL in all patients with epilepsy, they were detected as 3.90 (IQR=3.31‒7.22) ng/mL in healthy volunteers, and significantly increased in numbers for those with epilepsy (p<0.001). However, whereas the UCH-L1 levels were 8.50 (IQR=6.93‒11.16) ng/mL in the patients with epileptic seizures, they were 8.10 (IQR=6.22‒11.93) ng/mL in the non-seizure period, and no significant difference was detected (p=0.6123). When the UCH-L1 cut-off value was taken as 4.34 mg/mL in Receiver Operating Characteristic (ROC) Curve analysis, the sensitivity and specificity detected were 93.75 and 66.00%, respectively (AUG=0.801; p<0.0001; 95%CI 0.747‒0.848) for patients with epilepsy. CONCLUSION: Even though UCH-L1 levels significantly increased more in patients with epilepsy than in healthy individuals, there was no difference between epileptic seizure and non-seizure periods.

Circulating GFAP and Iba-1 levels are associated with pathophysiological sequelae in the thalamus in a pig model of mild TBI.

Serum biomarkers are promising tools for evaluating patients following traumatic brain injury (TBI). However, their relationship with diffuse histopathology remains unclear. Additionally, translatability is a focus of neurotrauma research, however, studies using translational animal models are limited. Here, we evaluated associations between circulating biomarkers and acute thalamic histopathology in a translational micro pig model of mTBI. Serum samples were collected pre-injury, and 1 min-6 h following mTBI. Markers of neuronal injury (Ubiquitin Carboxy-terminal Hydrolase L1 [UCH-L1]), microglial/macrophage activation (Ionized calcium binding adaptor molecule-1 [Iba-1]) and interleukin-6 [IL-6]) and astrogliosis/astrocyte damage (glial fibrillary acidic protein [GFAP]) were measured. Axonal injury and histological features of neurons and glia were also investigated using immunofluorescent labeling and correlated to serum levels of the associated biomarkers. Consistent with prior experimental and human studies, GFAP, was highest at 6 h post-injury, while no substantial changes were observed in UCH-L1, Iba-1 or IL-6 over 6 h. This study also found promising associations between thalamic glial histological signatures and ensuing release of Iba-1 and GFAP into the circulation. Our findings suggest that in diffuse injury, monitoring serum Iba-1 and GFAP levels can provide clinically relevant insight into the underlying acute pathophysiology and biomarker release kinetics following mTBI, providing previously underappreciated diagnostic capability.

Biomarkers May Predict Unfavorable Neurological Outcome after Mild Traumatic Brain Injury.

The objective of this study was to determine if initial or repeat measurements of serum concentrations of glial fibrillary acidic protein (GFAP) or ubiquitin C-terminal hydrolase L1 (UCH-L1) are predictive of an acute unfavorable neurological outcome in patients who present to the emergency department (ED) with brain injury and an initial Glasgow Coma Scale Score (GCS) of 14-15. This multi-center observational trial included brain-injured adults presenting to the ED, receiving a head computed tomography (CT) and venipuncture for biomarker concentration measurements within 6 h of injury. Subjects had repeat serum sampling and GCS scores every 4 h for the first 24 h, if available for assessment. We analyzed blood samples using an enzyme-linked immunosorbent assay approved by the Food and Drug Administration (FDA). Wilcoxin two-sample test was used to compare initial and repeat serum concentrations for both biomarkers between CT-positive patients who did not have an acute unfavorable neurological outcome and those patients who did. A total of 145 enrolled subjects had adequate data for analysis; 69 were CT-positive, 74 were CT-negative, and 2 were CT-inconclusive. Five subjects developed an acute unfavorable neurological outcome, defined as need for intracranial pressure monitoring, craniotomy, persistent neurological deficits, or death resulting from brain injury. Initial median serum concentrations of GFAP and UCH-L1 (obtained <6 h from injury) were significantly greater in CT-positive patients who had an acute unfavorable neurological outcome than in CT-positive patients who did not (GFAP: 5237 pg/mL [IQR 4511, 8180] versus 283.5 pg/mL [IQR 107, 1123]; p = 0.026; UCH-L1: 3329 pg/mL [QR 1423, 5010] versus 679.5 pg/mL [IQR 363, 1100] p = 0.014). Repeat serum testing (6- < 12 h from injury) showed that UCH-L1 serum concentration, but not GFAP, was also significantly greater in the acute unfavorable neurological outcome group than in those without an unfavorable outcome: 1088 pg/mL versus 374 pg/mL; p = 0.041.