Pathophysiology and treatment of cerebral edema in traumatic brain injury

Neuritin promotes autophagic flux by inhibiting the cGAS-STING pathway to alleviate brain injury after subarachnoid haemorrhage

BACKGROUND

Early brain injury (EBI) is closely associated with poor prognosis in patients with subarachnoid haemorrhage (SAH), with autophagy playing a pivotal role in EBI. However, research has shown that the stimulator of interferon genes (STING) pathway impacts autophagic flux. While the regulatory impact of neuritin on EBI and autophagic flux has been established previously, the underlying mechanism remains unclear. This study aimed to determine the role of the cGAS-STING pathway in neuritin-mediated regulation of autophagic flux following SAH.

METHODS

A SAH model was established in male Sprague-Dawley rats via intravascular perforation. Neuritin overexpressions using adeno-associated virus, the STING antagonist "C-176," and the activator, "CMA," were determined to investigate the cGAS-STING pathway's influence on autophagic flux and brain injury post-SAH, along with the neuritin's regulatory effect on STING. In this study, SAH grade, neurological score, haematoxylin and eosin (H&E) staining, brain water content (BWC), sandwich enzyme-linked immunosorbent assay, Evans blue staining, immunofluorescence staining, western blot analysis, and transmission electron microscopy (TEM) were examined.

RESULTS

Neuritin overexpression significantly ameliorated neurobehavioural scores, blood-brain barrier injury, brain oedema, and impaired autophagic flux in SAH-induced rats. STING expression remarkably increased post-SAH. C-176 and CMA mitigated and aggravated autophagic flux injury and brain injury, respectively, while inhibiting and enhancing STING, respectively. Particularly, CMA treatment nullified the protective effects of neuritin against autophagic flux and mitigated brain injury.

CONCLUSION

Neuritin alleviated EBI by restoring impaired autophagic flux after SAH through the regulation of the cGAS-STING pathway.

Risk factors for neurological disability outcomes in patients under extracorporeal membrane oxygenation following cardiac arrest: An observational study

OBJECTIVES

This study aimed to identify factors associated with neurological and disability outcomes in patients who underwent ECMO following cardiac arrest.

METHODS

This retrospective, single-center, observational study included adult patients who received ECMO treatment for in-hospital cardiac arrest (IHCA) or out-of-hospital cardiac arrest (OHCA) between February 2016 and March 2020. Factors associated with neurological and disability outcomes in these patients who underwent ECMO were assessed.

SETTING

Hamad General Hospital, Qatar.

MAIN OUTCOME MEASURES

Neurological disability outcomes were assessed using the Modified Rankin Scale (mRS) and the Cerebral Performance Category (CPC) scale.

RESULTS

Among the 48 patients included, 37 (77 %) experienced OHCA, and 11 (23 %) had IHCA. The 28-day survival rate was 14 (29.2 %). Of the survivors, 9 (64.3 %) achieved a good neurological outcome, while 5 (35.7 %) experienced poor neurological outcomes. Regarding disability, 5 (35.7 %) of survivors had no disability, while 9 (64.3 %) had some form of disability. The results showed significantly shorter median time intervals in minutes, including collapse to cardiopulmonary resuscitation (CPR) (3 vs. 6, P = 0.001), CPR duration (12 vs. 35, P = 0.001), CPR to extracorporeal cardiopulmonary resuscitation (ECPR) (20 vs. 40, P = 0.001), and collapse-to-ECPR (23 vs. 45, P = 0.001), in the good outcome group compared to the poor outcome group.

CONCLUSION

This study emphasizes the importance of minimizing the time between collapse and CPR/ECMO initiation to improve neurological outcomes and reduce disability in cardiac arrest patients. However, no significant associations were found between outcomes and other demographic or clinical variables in this study. Further research with a larger sample size is needed to validate these findings.

IMPLICATIONS FOR CLINICAL PRACTICE

The study underscores the significance of reducing the time between collapse and the initiation of CPR and ECMO. Shorter time intervals were associated with improved neurological outcomes and reduced disability in cardiac arrest patients.

Role of substance P in cerebral edema and association with an estimated specific gravity of the brain and an outcome prediction in post-traumatic cerebral edema

Purpose

The study aims to evaluate the role of substance P in cerebral edema and outcomes associated with acute TBI.

Method

Patients with acute TBI who presented within 6 h and a CT scan showed predominantly cerebral edema were included in the study. Substance P level was assessed from a serum sample collected within 6 h of trauma. We also evaluated the brain-specific gravity using the Brain View software.

Result

A total of 160 (128 male) patients were recruited. The median serum substance P concentration was 167.89 (IQR: 101.09-238.2). Substance P concentration was high in the early hours after trauma (p = 0.001). The median specific gravity of the entire brain was 1.04. Patients with a low Glasgow coma scale (GCS) at admission had a high concentration of the substance P. In the univariate analysis, low GCS, elevated serum concentrations of substance P level, high Rotterdam grade, high cerebral edema grade, a high international normalized ratio value, and high blood sugar levels were associated with poor outcomes at six months. In logistic regression analysis, low GCS at admission, high cerebral edema grade, and elevated blood sugar level were strongly associated with poor outcomes at six months. The area under the receiver operating characteristic curve was 0.884 (0.826-0.941).

Conclusion

Serum substance P is strongly associated with the severity of cerebral edema after TBI. However, brain-specific gravity does not directly correlate with posttraumatic cerebral edema severity. Serum substance P does not influence the clinical outcome of traumatic brain injury.

Recent advances on signaling pathways and their inhibitors in spinal cord injury

Spinal cord injury (SCI) is a serious and disabling central nervous system injury. Its complex pathological mechanism can lead to sensory and motor dysfunction. It has been reported that signaling pathway plays a key role in the pathological process and neuronal recovery mechanism of SCI. Such as PI3K/Akt, MAPK, NF-κB, and Wnt/β-catenin signaling pathways. According to reports, various stimuli and cytokines activate these signaling pathways related to SCI pathology, thereby participating in the regulation of pathological processes such as inflammation response, cell apoptosis, oxidative stress, and glial scar formation after injury. Activation or inhibition of relevant pathways can delay inflammatory response, reduce neuronal apoptosis, prevent glial scar formation, improve the microenvironment after SCI, and promote neural function recovery. Based on the role of signaling pathways in SCI, they may be potential targets for the treatment of SCI. Therefore, understanding the signaling pathway and its inhibitors may be beneficial to the development of SCI therapeutic targets and new drugs. This paper mainly summarizes the pathophysiological process of SCI, the signaling pathways involved in SCI pathogenesis, and the potential role of specific inhibitors/activators in its treatment. In addition, this review also discusses the deficiencies and defects of signaling pathways in SCI research. It is hoped that this study can provide reference for future research on signaling pathways in the pathogenesis of SCI and provide theoretical basis for SCI biotherapy.

Effects of poloxamer 188 on traumatic brain injury

Traumatic Brain Injury (TBI) is a major cause of severe disability and death, resulting in significant health care and economic burden. Poloxamer 188, a synthetic tri-block copolymer approved by the FDA, has been studied for its potential effects on traumatic brain injury (TBI). The neuroprotective abilities of P188 have attracted significant attention. This systematic review aims to compile evidence of P188's effect on the treatment of TBI. A comprehensive literature search was conducted using PubMed, SCOPUS, and Google Scholar databases, which yielded 20 articles that satisfied the inclusion criteria. These articles have shown direct protective effects of P188 on brain tissue following TBI, including restitution of the increase cell membrane permeability, attenuation of neuronal necrosis and apoptosis, improvement of mitochondrial viability, reduction in axonal disruption, and restoration of the blood brain barrier. In animals, P188 has been shown to improve sensorimotor functions, as well as spatial learning and memory.

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.

Targeted Therapy of Spinal Cord Injury: Inhibition of Apoptosis Is a Promising Therapeutic Strategy

Spinal cord injury (SCI) is a serious disabling central nervous system injury that can lead to motor, sensory, and autonomic dysfunction below the injury level. SCI can be divided into primary injury and secondary injury according to pathological process. Primary injury is mostly irreversible, while secondary injury is a dynamic regulatory process. Apoptosis is an important pathological event of secondary injury and has a significant effect on the recovery of nerve function after SCI. Nerve cell death can further aggravate the microenvironment of the injured site, leading to neurological dysfunction and thus affect the clinical outcome of patients. Therefore, apoptosis plays a crucial role in the pathological progression of secondary SCI, while inhibiting apoptosis may be a promising therapeutic strategy for SCI. This review will summarize and explore the factors that lead to cell death after SCI, the influence of cross talk between signaling pathways and pathways involved in apoptosis and discuss the influence of apoptosis on SCI, and the therapeutic significance of targeting apoptosis on SCI. This review helps us to understand the role of apoptosis in secondary SCI and provides a theoretical basis for the treatment of SCI based on apoptosis.

Friedman's Gradient-Boosting Algorithm Predicts Lactate-Pyruvate Ratio Trends in Cases of Intracerebral Hemorrhages

OBJECTIVE

The local effects of an intracerebral hemorrhage (ICH) on surrounding brain tissue can be detected bedside using multimodal brain monitoring techniques. The aim of this study is to design a gradient boosting regression model using the R package boostmtree with the ability to predict lactate-pyruvate ratio measurements in ICH.

METHODS

We performed a retrospective analysis of 6 spontaneous ICH and 6 traumatic ICH patients who underwent surgical removal of the clot with microdialysis catheters placed in the perihematomal zone. Predictors of glucose, lactate, pyruvate, age, sex, diagnosis, and operation status were used to design our model.

RESULTS

In a holdout analysis, the model forecasted lactate-pyruvate ratio trends in a representative in-sample testing set. We anticipate that boostmtree could be applied to designs of similar regression models to analyze trends in other multimodal monitoring features across other types of acute brain injury.

CONCLUSIONS

The model successfully predicted hourly lactate-pyruvate ratios in spontaneous ICH and traumatic ICH cases after the hemorrhage evacuation and displayed significantly better performance than linear models. Our results suggest that boostmtree may be a powerful tool in developing more advanced mathematical models to assess other multimodal monitoring parameters for cases in which the perihematomal environment is monitored.

Aquaporins: Gatekeepers of Fluid Dynamics in Traumatic Brain Injury

Aquaporins (AQPs), particularly AQP4, play a crucial role in regulating fluid dynamics in the brain, impacting the development and resolution of edema following traumatic brain injury (TBI). This review examines the alterations in AQP expression and localization post-injury, exploring their effects on brain edema and overall injury outcomes. We discuss the underlying molecular mechanisms regulating AQP expression, highlighting potential therapeutic strategies to modulate AQP function. These insights provide a comprehensive understanding of AQPs in TBI and suggest novel approaches for improving clinical outcomes through targeted interventions.

Bedside ultrasound-assisted puncture and drainage under local anesthesia: A novel approach for early post-operative space-occupying tumor bed cysts of glioma resection

OBJECTIVES

To investigate the causes of space-occupying tumor bed cysts formed early after glioma resection by measuring the osmotic pressure gradient between cystic fluid, serum, and cerebrospinal fluid (CSF) and propose a new method of bedside ultrasound-assisted puncture and drainage (UAP&D) under local anesthesia for treatment.

METHODS

Bedside UAP&D under local anesthesia was performed through a burr hole on the skull flap.Following a successful puncture, cystic fluid was collected, while blood and CSF were obtained through vein and lumbar puncture, respectively. The osmotic pressure of all fluids collected was measured. The appearance, biochemical composition, and results of microbial culture of cystic fluid and CSF were analyzed. Within 24 h after UAP&D, a CT examination and Glasgow coma scale (GCS) were assessed.

RESULTS

The osmotic pressure of cystic fluid was higher than that of serum and CSF. White blood cell count and protein concentration were higher in the cystic fluid compared to the CSF. Conversely, the concentration of chloride ions and glucose were lower. CT scan confirmed the correct placement of the cysts' drainage tube and that the cysts' volume decreased significantly with continued drainage. Accompanied by a reduction in the volume of cysts, there were significant improvements in GCS score within 24 h after UAP&D. All drainage tubes were removed within 2-5 days, and no puncture tract hemorrhage or infection was observed.

CONCLUSION

The osmotic pressure gradient between cystic fluid, serum, and CSF caused the formation of early post-operative space-occupying tumor bed cysts for glioma. UAP&D aligns with the concept that micro-invasive neurosurgery is an effective treatment method for such cysts.

The deletion of AQP4 and TRPV4 affects astrocyte swelling/volume recovery in response to ischemia-mimicking pathologies

Introduction

Astrocytic Transient receptor potential vanilloid 4 (TRPV4) channels, together with Aquaporin 4 (AQP4), are suspected to be the key players in cellular volume regulation, and therefore may affect the development and severity of cerebral edema during ischemia. In this study, we examined astrocytic swelling/volume recovery in mice with TRPV4 and/or AQP4 deletion in response to in vitro ischemic conditions, to determine how the deletion of these channels can affect the development of cerebral edema.

Methods

We used three models of ischemia-related pathological conditions: hypoosmotic stress, hyperkalemia, and oxygenglucose deprivation (OGD), and observed their effect on astrocyte volume changes in acute brain slices of Aqp4-/-, Trpv4-/- and double knockouts. In addition, we employed single-cell RT-qPCR to assess the effect of TRPV4 and AQP4 deletion on the expression of other ion channels and transporters involved in the homeostatic functioning of astrocytes.

Results

Quantification of astrocyte volume changes during OGD revealed that the deletion of AQP4 reduces astrocyte swelling, while simultaneous deletion of both AQP4 and TRPV4 leads to a disruption of astrocyte volume recovery during the subsequent washout. Of note, astrocyte exposure to hypoosmotic stress or hyperkalemia revealed no differences in astrocyte swelling in the absence of AQP4, TRPV4, or both channels. Moreover, under ischemia-mimicking conditions, we identified two distinct subpopulations of astrocytes with low and high volumetric responses (LRA and HRA), and their analyses revealed that mainly HRA are affected by the deletion of AQP4, TRPV4, or both channels. Furthermore, gene expression analysis revealed reduced expression of the ion transporters KCC1 and ClC2 as well as the receptors GABAB and NMDA in Trpv4-/- mice. The deletion of AQP4 instead caused reduced expression of the serine/cysteine peptidase inhibitor Serpina3n.

Discussion

Thus, we showed that in AQP4 or TRPV4 knockouts, not only the specific function of these channels is affected, but also the expression of other proteins, which may modulate the ischemic cascade and thus influence the final impact of ischemia.

Advancements in neuroregenerative and neuroprotective therapies for traumatic spinal cord injury

Traumatic spinal cord injuries (SCIs) continue to be a major healthcare concern, with a rising prevalence worldwide. In response to this growing medical challenge, considerable scientific attention has been devoted to developing neuroprotective and neuroregenerative strategies aimed at improving the prognosis and quality of life for individuals with SCIs. This comprehensive review aims to provide an up-to-date and thorough overview of the latest neuroregenerative and neuroprotective therapies currently under investigation. These strategies encompass a multifaceted approach that include neuropharmacological interventions, cell-based therapies, and other promising strategies such as biomaterial scaffolds and neuro-modulation therapies. In addition, the review discusses the importance of acute clinical management, including the role of hemodynamic management as well as timing and technical aspects of surgery as key factors mitigating the secondary injury following SCI. In conclusion, this review underscores the ongoing scientific efforts to enhance patient outcomes and quality of life, focusing on upcoming strategies for the management of traumatic SCI. Each section provides a working knowledge of the fundamental preclinical and patient trials relevant to clinicians while underscoring the pathophysiologic rationale for the therapies.

Correlating Age and Hematoma Volume with Extent of Midline Shift in Acute Subdural Hematoma Patients: Validation of an Artificial Intelligence Tool for Volumetric Analysis

OBJECTIVE

Decision for intervention in acute subdural hematoma patients is based on a combination of clinical and radiographic factors. Age has been suggested as a factor to be strongly considered when interpreting midline shift (MLS) and hematoma volume data for assessing critical clinical severity during operative intervention decisions for acute subdural hematoma patients. The objective of this study was to demonstrate the use of an automated volumetric analysis tool to measure hematoma volume and MLS and quantify their relationship with age.

METHODS

A total of 1789 acute subdural hematoma patients were analyzed using qER-Quant software (Qure.ai, Mumbai, India) for MLS and hematoma volume measurements. Univariable and multivariable regressions analyzed association between MLS, hematoma volume, age, and MLS:hematoma volume ratio.

RESULTS

In comparison to young patients (≤ 70 years), old patients (>70 years) had significantly higher average hematoma volume (old: 62.2 mL vs. young 46.8 mL, P < 0.0001), lower average MLS (old: 6.6 mm vs. young: 7.4 mm, P = 0.025), and lower average MLS:hematoma volume ratio (old: 0.11 mm/mL vs. young 0.15 mm/mL, P < 0.0001). Young patients had an average of 1.5 mm greater MLS for a given hematoma volume in comparison to old patients. With increasing age, the ratio between MLS and hematoma volume significantly decreases (P = 0.0002).

CONCLUSIONS

Commercially available, automated, artificial intelligence (AI)-based tools may be used for obtaining quantitative radiographic measurement data in patients with acute subdural hematoma. Our quantitative results are consistent with the qualitative relationship previously established between age, hematoma volume, and MLS, which supports the validity of using AI-based tools for acute subdural hematoma volume estimation.

Modelling midline shift and ventricle collapse in cerebral oedema following acute ischaemic stroke

In ischaemic stroke, a large reduction in blood supply can lead to the breakdown of the blood-brain barrier and to cerebral oedema after reperfusion therapy. The resulting fluid accumulation in the brain may contribute to a significant rise in intracranial pressure (ICP) and tissue deformation. Changes in the level of ICP are essential for clinical decision-making and therapeutic strategies. However, the measurement of ICP is constrained by clinical techniques and obtaining the exact values of the ICP has proven challenging. In this study, we propose the first computational model for the simulation of cerebral oedema following acute ischaemic stroke for the investigation of ICP and midline shift (MLS) relationship. The model consists of three components for the simulation of healthy blood flow, occluded blood flow and oedema, respectively. The healthy and occluded blood flow components are utilized to obtain oedema core geometry and then imported into the oedema model for the simulation of oedema growth. The simulation results of the model are compared with clinical data from 97 traumatic brain injury patients for the validation of major model parameters. Midline shift has been widely used for the diagnosis, clinical decision-making, and prognosis of oedema patients. Therefore, we focus on quantifying the relationship between ICP and midline shift (MLS) and identify the factors that can affect the ICP-MLS relationship. Three major factors are investigated, including the brain geometry, blood-brain barrier damage severity and the types of oedema (including rare types of oedema). Meanwhile, the two major types (stress and tension/compression) of mechanical brain damage are also presented and the differences in the stress, tension, and compression between the intraparenchymal and periventricular regions are discussed. This work helps to predict ICP precisely and therefore provides improved clinical guidance for the treatment of brain oedema.

Risk factors and predictive model of cerebral edema after road traffic accidents-related traumatic brain injury

PURPOSE

Cerebral edema (CE) is the main secondary injury following traumatic brain injury (TBI) caused by road traffic accidents (RTAs). It is challenging to be predicted timely. In this study, we aimed to develop a prediction model for CE by identifying its risk factors and comparing the timing of edema occurrence in TBI patients with varying levels of injuries.

METHODS

This case-control study included 218 patients with TBI caused by RTAs. The cohort was divided into CE and non-CE groups, according to CT results within 7 days. Demographic data, imaging data, and clinical data were collected and analyzed. Quantitative variables that follow normal distribution were presented as mean ± standard deviation, those that do not follow normal distribution were presented as median (Q1, Q3). Categorical variables were expressed as percentages. The Chi-square test and logistic regression analysis were used to identify risk factors for CE. Logistic curve fitting was performed to predict the time to secondary CE in TBI patients with different levels of injuries. The efficacy of the model was evaluated using the receiver operator characteristic curve.

RESULTS

According to the study, almost half (47.3%) of the patients were found to have CE. The risk factors associated with CE were bilateral frontal lobe contusion, unilateral frontal lobe contusion, cerebral contusion, subarachnoid hemorrhage, and abbreviated injury scale (AIS). The odds ratio values for these factors were 7.27 (95% confidence interval (CI): 2.08 - 25.42, p = 0.002), 2.85 (95% CI: 1.11 - 7.31, p = 0.030), 2.62 (95% CI: 1.12 - 6.13, p = 0.027), 2.44 (95% CI: 1.25 - 4.76, p = 0.009), and 1.5 (95% CI: 1.10 - 2.04, p = 0.009), respectively. We also observed that patients with mild/moderate TBI (AIS ≤ 3) had a 50% probability of developing CE 19.7 h after injury (χ2 = 13.82, adjusted R2 = 0.51), while patients with severe TBI (AIS > 3) developed CE after 12.5 h (χ2 = 18.48, adjusted R2 = 0.54). Finally, we conducted a receiver operator characteristic curve analysis of CE time, which showed an area under the curve of 0.744 and 0.672 for severe and mild/moderate TBI, respectively.

CONCLUSION

Our study found that the onset of CE in individuals with TBI resulting from RTAs was correlated with the severity of the injury. Specifically, those with more severe injuries experienced an earlier onset of CE. These findings suggest that there is a critical time window for clinical intervention in cases of CE secondary to TBI.

Advances in electroactive bioscaffolds for repairing spinal cord injury

Spinal cord injury (SCI) is a devastating neurological disorder, leading to loss of motor or somatosensory function, which is the most challenging worldwide medical problem. Re-establishment of intact neural circuits is the basis of spinal cord regeneration. Considering the crucial role of electrical signals in the nervous system, electroactive bioscaffolds have been widely developed for SCI repair. They can produce conductive pathways and a pro-regenerative microenvironment at the lesion site similar to that of the natural spinal cord, leading to neuronal regeneration and axonal growth, and functionally reactivating the damaged neural circuits. In this review, we first demonstrate the pathophysiological characteristics induced by SCI. Then, the crucial role of electrical signals in SCI repair is introduced. Based on a comprehensive analysis of these characteristics, recent advances in the electroactive bioscaffolds for SCI repair are summarized, focusing on both the conductive bioscaffolds and piezoelectric bioscaffolds, used independently or in combination with external electronic stimulation. Finally, thoughts on challenges and opportunities that may shape the future of bioscaffolds in SCI repair are concluded.

The protective effects of methylene blue on astrocytic swelling after cerebral ischemia-reperfusion injuries are mediated by Aquaporin-4 and metabotropic glutamate receptor 5 activation

Methylene blue (MB) was found to exert neuroprotective effect on different brain diseases, such as ischemic stroke. This study assessed the MB effects on ischemia induced brain edema and its role in the inhibition of aquaporin 4 (AQP4) and metabotropic glutamate receptor 5 (mGluR5) expression. Rats were exposed 1 h transient middle cerebral artery occlusion (tMCAO), and MB was injected intravenously following reperfusion (3 mg/kg). Magnetic resonance imaging (MRI) and 2,3,5-triphenyltetrazolium chloride (TTC) staining was performed 48 h after the onset of tMCAO to evaluate the brain infarction and edema. Brain tissues injuries as well as the glial fibrillary acidic protein (GFAP), AQP4 and mGluR5 expressions were detected. Oxygen and glucose deprivation/reoxygenation (OGD/R) was performed on primary astrocytes (ASTs) to induce cell swelling. MB was administered at the beginning of reoxygenation, and the perimeter of ASTs was measured by GFAP immunofluorescent staining. 3,5-dihydroxyphenylglycine (DHPG) and fenobam were given at 24 h before OGD to examine their effects on MB functions on AST swelling and AQP4 expression. MB remarkably decreased the volumes of T2WI and ADC lesions, as well as the cerebral swelling. Consistently, MB treatment significantly decreased GFAP, mGluR5 and AQP4 expression at 48 h after stroke. In the cultivated primary ASTs, OGD/R and DHPG significantly increased ASTs volume as well as AQP4 expression, which was reversed by MB and fenobam treatment. The obtained results highlight that MB decreases the post-ischemic brain swelling by regulating the activation of AQP4 and mGluR5, suggesting potential applications of MB on clinical ischemic stroke treatment.

Traumatic injury causes selective degeneration and TDP-43 mislocalization in human iPSC-derived C9orf72-associated ALS/FTD motor neurons

A hexanucleotide repeat expansion (HRE) in C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, patients with the HRE exhibit a wide disparity in clinical presentation and age of symptom onset suggesting an interplay between genetic background and environmental stressors. Neurotrauma as a result of traumatic brain or spinal cord injury has been shown to increase the risk of ALS/FTD in epidemiological studies. Here, we combine patient-specific induced pluripotent stem cells (iPSCs) with a custom-built device to deliver biofidelic stretch trauma to C9orf72 patient and isogenic control motor neurons (MNs) in vitro. We find that mutant but not control MNs exhibit selective degeneration after a single incident of severe trauma, which can be partially rescued by pretreatment with a C9orf72 antisense oligonucleotide. A single incident of mild trauma does not cause degeneration but leads to cytoplasmic accumulation of TDP-43 in C9orf72 MNs. This mislocalization, which only occurs briefly in isogenic controls, is eventually restored in C9orf72 MNs after 6 days. Lastly, repeated mild trauma ablates the ability of patient MNs to recover. These findings highlight alterations in TDP-43 dynamics in C9orf72 ALS/FTD patient MNs following traumatic injury and demonstrate that neurotrauma compounds neuropathology in C9orf72 ALS/FTD. More broadly, our work establishes an in vitro platform that can be used to interrogate the mechanistic interactions between ALS/FTD and neurotrauma.

Recent insights from non-mammalian models of brain injuries: an emerging literature

Traumatic brain injury (TBI) is a major global health concern and is increasingly recognized as a risk factor for neurodegenerative diseases including Alzheimer's disease (AD) and chronic traumatic encephalopathy (CTE). Repetitive TBIs (rTBIs), commonly observed in contact sports, military service, and intimate partner violence (IPV), pose a significant risk for long-term sequelae. To study the long-term consequences of TBI and rTBI, researchers have typically used mammalian models to recapitulate brain injury and neurodegenerative phenotypes. However, there are several limitations to these models, including: (1) lengthy observation periods, (2) high cost, (3) difficult genetic manipulations, and (4) ethical concerns regarding prolonged and repeated injury of a large number of mammals. Aquatic vertebrate model organisms, including Petromyzon marinus (sea lampreys), zebrafish (Danio rerio), and invertebrates, Caenorhabditis elegans (C. elegans), and Drosophila melanogaster (Drosophila), are emerging as valuable tools for investigating the mechanisms of rTBI and tauopathy. These non-mammalian models offer unique advantages, including genetic tractability, simpler nervous systems, cost-effectiveness, and quick discovery-based approaches and high-throughput screens for therapeutics, which facilitate the study of rTBI-induced neurodegeneration and tau-related pathology. Here, we explore the use of non-vertebrate and aquatic vertebrate models to study TBI and neurodegeneration. Drosophila, in particular, provides an opportunity to explore the longitudinal effects of mild rTBI and its impact on endogenous tau, thereby offering valuable insights into the complex interplay between rTBI, tauopathy, and neurodegeneration. These models provide a platform for mechanistic studies and therapeutic interventions, ultimately advancing our understanding of the long-term consequences associated with rTBI and potential avenues for intervention.

Cerebral Infarction Due to Post-traumatic Cerebral Vasospasm in a 12-Year-Old Female

Cerebral infarction due to post-traumatic cerebral vasospasm is rare. Although some modalities are recommended to detect post-traumatic cerebral vasospasm, its diagnosis remains controversial and challenging. Therefore, in this report, we will use a case report to highlight challenges and to delineate the characteristics of post-traumatic cerebral vasospasm in pediatric patients, including the diagnostic and treatment options. A 12-year-old female was admitted to our hospital following a motor vehicle collision. Her consciousness was severely impaired. Initial computed tomography (CT) revealed an acute subdural hematoma along the tentorium, and a focal subarachnoid hemorrhage was observed in the Sylvian fissure. The patient underwent the insertion of an intracranial pressure sensor and received therapy for increased intracranial pressure (ICP) control under sedation. On the second day, CT angiography (CTA) revealed no signs of arterial abnormality. A patient who is comatose or under sedation has masked neurological symptoms. Thus, new neurological events could only be detected via an intracranial pressure sensor. Her ICP increased on the seventh day, and a CT scan showed a new cerebral infarction in the right middle cerebral artery (MCA) region. We performed decompressive craniectomy to reduce ICP. Postoperative CTA confirmed severe vasospasm in the right MCA. The severe cerebral vasospasm induced the cerebral infarction. Our review suggests that physicians in trauma departments should frequently perform vascular evaluations by CTA, magnetic resonance angiography (MRA), transcranial Doppler ultrasound, or digital subtraction angiography (DSA), especially within two weeks from onset, to detect post-traumatic cerebral vasospasm.

Risk of Subdural Hematoma Expansion in Patients With End-Stage Renal Disease: Continuous Venovenous Hemodialysis Versus Intermittent Hemodialysis

BACKGROUND AND OBJECTIVES

Subdural hematoma (SDH) patients with end-stage renal disease (ESRD) require renal replacement therapy in addition to neurological management. We sought to determine whether continuous venovenous hemodialysis (CVVHD) or intermittent hemodialysis (iHD) is associated with higher rates of SDH re-expansion as well as morbidity and mortality.

METHODS

Hemodialysis-dependent patients with ESRD who were discovered to have an SDH were retrospectively identified from 2016 to 2022. Rates of SDH expansion during CVVHD vs iHD were compared. Hemodialysis mode was included in a multivariate logistic regression model to test for independent association with SDH expansion and mortality.

RESULTS

A total of 123 hemodialysis-dependent patients with ESRD were discovered to have a concomitant SDH during the period of study. Patients who received CVVHD were on average 10.2 years younger ( P < .001), more likely to have traumatic SDH (47.7% vs 19.0%, P < .001), and more likely to have cirrhosis (25.0% vs 10.1%, P = .029). SDH expansion affecting neurological function occurred more frequently during iHD compared with CVVHD (29.7% vs 12.0%, P = .013). Multivariate logistic regression analysis found that CVVHD was independently associated with decreased risk of SDH affecting neurological function (odds ratio 0.25, 95% CI 0.08-0.65). Among patients who experienced in-hospital mortality or were discharged to hospice, 5% suffered a neurologically devastating SDH expansion while on CVVHD compared with 35% on iHD.

CONCLUSION

CVVHD was independently associated with decreased risk of neurologically significant SDH expansion. Therefore, receiving renal replacement therapy through a course of CVVHD may increase SDH stability in patients with ESRD.

Edema progression in proximity to traumatic microbleeds: evolution of cytotoxic and vasogenic edema on serial MRI

Introduction

Although cerebral edema is common following traumatic brain injury (TBI), its formation and progression are poorly understood. This is especially true for the mild TBI population, who rarely undergo magnetic resonance imaging (MRI) studies, which can pick up subtle structural details not visualized on computed tomography, in the first few days after injury. This study aimed to visually classify and quantitatively measure edema progression in relation to traumatic microbleeds (TMBs) in a cohort of primarily mild TBI patients up to 30 days after injury. Researchers hypothesized that hypointense lesions on Apparent Diffusion Coefficient (ADC) detected acutely after injury would evolve into hyperintense Fluid Attenuated Inversion Recover (FLAIR) lesions.

Methods

This study analyzed the progression of cerebral edema after acute injury using multimodal MRI to classify TMBs as potential edema-related biomarkers. ADC and FLAIR MRI were utilized for edema classification at three different timepoints: ≤48 hours, ~1 week, and 30 days after injury. Hypointense lesions on ADC (ADC+) suggested the presence of cytotoxic edema while hyperintense lesions on FLAIR (FLAIR+) suggested vasogenic edema. Signal intensity Ratio (SIR) calculations were made using ADC and FLAIR to quantitatively confirm edema progression.

Results

Our results indicated the presence of ADC+ lesions ≤48 hours and ~1 week were associated with FLAIR+ lesions at ~1 week and 30 days, respectively, suggesting some progression of cytotoxic edema to vasogenic edema over time. Ten out of 15 FLAIR+ lesions at 30 days (67%) were ADC+ ≤48 hours. However, ADC+ lesions ≤48 hours were not associated with FLAIR+ lesions at 30 days; 10 out of 25 (40%) ADC+ lesions ≤48 hours were FLAIR+ at 30 days, which could indicate that some lesions resolved or were not visualized due to associated atrophy or tissue necrosis. Quantitative analysis confirmed the visual progression of some TMB lesions from ADC+ to FLAIR+. FLAIR SIRs at ~1 week were significantly higher when lesions were ADC+ ≤48 hours (1.22 [1.08-1.32] vs 1.03 [0.97-1.11], p=0.002).

Conclusion

Awareness of how cerebral edema can evolve in proximity to TMBs acutely after injury may facilitate identification and monitoring of patients with traumatic cerebrovascular injury and assist in development of novel therapeutic strategies.

Dehydroevodiamine ameliorates neurological dysfunction after traumatic brain injury in mice via regulating the SIRT1/FOXO3a/Bim pathway

BACKGROUND

Traumatic Brain Injury (TBI) poses a considerable public health challenge, resulting in mortality, disability, and economic strain. Dehydroevodiamine (DEDM) is a natural compound derived from a traditional Chinese herbal medicine. Prior studies have substantiated the neuroprotective attributes of this compound in the context of TBI. Nevertheless, a comprehensive comprehension of the exact mechanisms responsible for its neuroprotective effects remains elusive. It is imperative to elucidate the precise intrinsic mechanisms underlying the neuroprotective actions of DEDM.

PURPOSE

The aim of this investigation was to elucidate the mechanism underlying DEDM treatment in TBI utilizing both in vivo and in vitro models. Specifically, our focus was on comprehending the impact of DEDM on the Sirtuin1 (SIRT1) / Forkhead box O3 (FOXO3a) / Bcl-2-like protein 11 (Bim) pathway, a pivotal player in TBI-induced cell death attributed to oxidative stress.

STUDY DESIGN AND METHODS

We established a TBI mouse model via the weight drop method. Following continuous intraperitoneal administration, we assessed the neurological dysfunction using the Modified Neurological Severity Score (mNSS) and behavioral assay, followed by sample collection. Secondary brain damage in mice was evaluated through Nissl staining, brain water content measurement, Evans blue detection, and Western blot assays. We scrutinized the expression levels of oxidative stress-related indicators and key proteins for apoptosis. The intricate mechanism of DEDM in TBI was further explored through immunofluorescence, Co-immunoprecipitation (Co-IP) assays, real-time quantitative PCR (RT-qPCR), dual-luciferase assays and western blotting. Additionally, we further investigated the specific therapeutic mechanism of DEDM in an oxidative stress cell model.

RESULTS

The results indicated that DEDM effectively ameliorated oxidative stress and apoptosis post-TBI, mitigating neurological dysfunction and brain injury in mice. DEDM facilitated the deacetylation of FOXO3a by up-regulating the expression of the deacetylase SIRT1, consequently suppressing Bim expression. This mechanism contributed to the alleviation of neurological injury and symptom improvement in TBI-afflicted mice. Remarkably, SIRT1 emerged as a central mediator in the overall treatment mechanism.

CONCLUSIONS

DEDM exerted significant neuroprotective effects on TBI mice by modulating the SIRT1/FOXO3a/Bim pathway. Our innovative research provides a basis for further exploration of the clinical therapeutic potential of DEDM in the context of TBI.

Research on the classification of early-stage brain edema by combining intrinsic optical signal imaging and laser speckle contrast imaging

The early detection and pathological classification of brain edema are very important for symptomatic treatment. The dual-optical imaging system (DOIS) consists of intrinsic optical signal imaging (IOSI) and laser speckle contrast imaging (LSCI), which can acquire cerebral hemodynamic parameters of mice in real-time, including changes of oxygenated hemoglobin concentration ( Δ C HbO 2 ), deoxyhemoglobin concentration (ΔCHbR) and relative cerebral blood flow (rCBF) within the field of view. The slope sum of Δ C HbO 2 , ΔCHbR and rCBF was proposed to classify vasogenic edema (VE) and cytotoxic edema (CE). The slope sum values in the VE and CE group remain statistically different and the classification results provide higher accuracy of more than 93% for early brain edema detection. In conclusion, the differences of hemodynamic parameters between VE and CE in the early stage were revealed and the method helps in the classification of early brain edema.

Similarities in the Electrographic Patterns of Delayed Cerebral Infarction and Brain Death After Aneurysmal and Traumatic Subarachnoid Hemorrhage

While subarachnoid hemorrhage is the second most common hemorrhagic stroke in epidemiologic studies, the recent DISCHARGE-1 trial has shown that in reality, three-quarters of focal brain damage after subarachnoid hemorrhage is ischemic. Two-fifths of these ischemic infarctions occur early and three-fifths are delayed. The vast majority are cortical infarcts whose pathomorphology corresponds to anemic infarcts. Therefore, we propose in this review that subarachnoid hemorrhage as an ischemic-hemorrhagic stroke is rather a third, separate entity in addition to purely ischemic or hemorrhagic strokes. Cumulative focal brain damage, determined by neuroimaging after the first 2 weeks, is the strongest known predictor of patient outcome half a year after the initial hemorrhage. Because of the unique ability to implant neuromonitoring probes at the brain surface before stroke onset and to perform longitudinal MRI scans before and after stroke, delayed cerebral ischemia is currently the stroke variant in humans whose pathophysiological details are by far the best characterized. Optoelectrodes located directly over newly developing delayed infarcts have shown that, as mechanistic correlates of infarct development, spreading depolarizations trigger (1) spreading ischemia, (2) severe hypoxia, (3) persistent activity depression, and (4) transition from clustered spreading depolarizations to a negative ultraslow potential. Furthermore, traumatic brain injury and subarachnoid hemorrhage are the second and third most common etiologies of brain death during continued systemic circulation. Here, we use examples to illustrate that although the pathophysiological cascades associated with brain death are global, they closely resemble the local cascades associated with the development of delayed cerebral infarcts.

Deplete and repeat: microglial CSF1R inhibition and traumatic brain injury

Traumatic brain injury (TBI) is a public health burden affecting millions of people. Sustained neuroinflammation after TBI is often associated with poor outcome. As a result, increased attention has been placed on the role of immune cells in post-injury recovery. Microglia are highly dynamic after TBI and play a key role in the post-injury neuroinflammatory response. Therefore, microglia represent a malleable post-injury target that could substantially influence long-term outcome after TBI. This review highlights the cell specific role of microglia in TBI pathophysiology. Microglia have been manipulated via genetic deletion, drug inhibition, and pharmacological depletion in various pre-clinical TBI models. Notably, colony stimulating factor 1 (CSF1) and its receptor (CSF1R) have gained much traction in recent years as a pharmacological target on microglia. CSF1R is a transmembrane tyrosine kinase receptor that is essential for microglia proliferation, differentiation, and survival. Small molecule inhibitors targeting CSF1R result in a swift and effective depletion of microglia in rodents. Moreover, discontinuation of the inhibitors is sufficient for microglia repopulation. Attention is placed on summarizing studies that incorporate CSF1R inhibition of microglia. Indeed, microglia depletion affects multiple aspects of TBI pathophysiology, including neuroinflammation, oxidative stress, and functional recovery with measurable influence on astrocytes, peripheral immune cells, and neurons. Taken together, the data highlight an important role for microglia in sustaining neuroinflammation and increasing risk of oxidative stress, which lends to neuronal damage and behavioral deficits chronically after TBI. Ultimately, the insights gained from CSF1R depletion of microglia are critical for understanding the temporospatial role that microglia develop in mediating TBI pathophysiology and recovery.

Characterization of Vasogenic and Cytotoxic Brain Edema Formation After Experimental Traumatic Brain Injury by Free Water Diffusion Magnetic Resonance Imaging

Brain edema formation is a key factor for secondary tissue damage after traumatic brain injury (TBI), however, the type of brain edema and the temporal profile of edema formation are still unclear. We performed free water imaging, a bi-tensor model based diffusion MRI analysis, to characterize vasogenic brain edema (VBE) and cytotoxic edema (CBE) formation up to 7 days after experimental TBI. Male C57/Bl6 mice were subjected to controlled cortical impact (CCI) or sham surgery and investigated by MRI 4h, 1, 2, 3, 5, and 7 days thereafter (n = 8/group). We determined mean diffusivity (MD) and free water (FW) in contusion, pericontusional area, ipsi- and contralateral brain tissue. Free (i.e., non-restricted) water was interpreted as VBE, restricted water as CBE. To verify the results, VBE formation was investigated by in-vivo 2-Photon Microscopy (2-PM) 48h after surgery. We found that MD and FW values decreased for 48h within the contusion, indicating the occurrence of CBE. In pericontusional tissue, MD and FW indices were increased at all time points, suggesting the formation of VBE. This was consistent with our results obtained by 2-PM. Taken together, CBE formation occurs for 48h after trauma and is restricted to the contusion, while VBE forms in pericontusional tissue up to 7 days after TBI. Our results indicate that free water magnetic resonance imaging may represent a promising tool to investigate vasogenic and cytotoxic brain edema in the laboratory and in patients.

Combined effect of trifluoperazine and sodium cromoglycate on reducing acute edema and limiting lasting functional impairments after spinal cord injury in rats

Edema formation is one of the very first events to occur after spinal cord injury (SCI) leading to an increase of the intrathecal pressure and consequently to serious spinal tissue and functional impairments. Current edema treatments are still symptomatic and/or non-specific. Since edema formation mechanisms are mainly described as vasogenic and cytotoxic, it becomes crucial to understand the interplay between these two subtypes. Acting on key targets to inhibit edema formation may reduce secondary damage and related functional impairments. In this study, we characterize the edema kinetic after T9-10 spinal contusion. We use trifluoperazine (TFP) to block the expression and the functional subcellular localization of aquaporin-4 supposed to be implicated in the cytotoxic edema formation. We also use sodium cromoglycate (SCG) to deactivate mast cell degranulation known to be implicated in the vasogenic edema formation. Our results show a significant reduction of edema after TFP treatment and after TFP-SCG combined treatment compared to control. This reduction is correlated with limited onset of initial sensorimotor impairments particularly after combined treatment. Our results highlight the importance of potential synergetic targets in early edema therapy after SCI as part of tissue sparing strategies.

Optic Nerve Sheath Diameter Sonography for the Diagnosis of Intracranial Hypertension in Traumatic Brain Injury: A Systematic Review and Meta-Analysis

OBJECTIVES

Timely diagnosis and management of elevated intracranial pressure (ICP) in patients with traumatic brain injury (TBI) can significantly reduce mortality rates. Ultrasound examination of the optic nerve sheath diameter (ONSD) is considered a potential, noninvasive, and effective method for assessing ICP. We conducted a systematic review and meta-analysis of ONSD ultrasound detection and invasive ICP monitoring methods to compare and evaluate the diagnostic accuracy of ONSD ultrasound detection methods for intracranial hypertension (IH) in patients with TBI.

METHODS

We searched the Web of Science, PubMed, and Embase databases to assess the diagnostic accuracy of ONSD sonography for predicting increased ICP. The 2 authors independently extracted the collected data. Simultaneously, the QUADAS-2 tool was used to evaluate the bias risk of each study and conducted random-effects meta-analyses for the accuracy and specificity of diagnosis, and calculated pooled estimates.

RESULTS

Ten studies with 512 patients were included. The diagnostic accuracy of ONSD sonography for IH was revealed as a pooled sensitivity of 0.85 (95% confidence interval [CI], 0.79-0.89) and specificity of 0.88 (95% CI, 0.80-0.93), compared with the invasive ICP monitoring standard for patients with TBI.

CONCLUSIONS

ONSD sonography may be a useful method for predicting increased ICP in adult patients with TBI. Further clinical studies are required to confirm the diagnostic value of ONSD sonography.

Broadening horizons: ferroptosis as a new target for traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide, with ~50 million people experiencing TBI each year. Ferroptosis, a form of regulated cell death triggered by iron ion-catalyzed and reactive oxygen species-induced lipid peroxidation, has been identified as a potential contributor to traumatic central nervous system conditions, suggesting its involvement in the pathogenesis of TBI. Alterations in iron metabolism play a crucial role in secondary injury following TBI. This study aimed to explore the role of ferroptosis in TBI, focusing on iron metabolism disorders, lipid metabolism disorders and the regulatory axis of system Xc-/glutathione/glutathione peroxidase 4 in TBI. Additionally, we examined the involvement of ferroptosis in the chronic TBI stage. Based on these findings, we discuss potential therapeutic interventions targeting ferroptosis after TBI. In conclusion, this review provides novel insights into the pathology of TBI and proposes potential therapeutic targets.

Investigation of the Binding Interaction of Mfsd2a with NEDD4-2 via Molecular Dynamics Simulations

Major facilitator superfamily domain-containing 2a (Mfsd2a) is a sodium-dependent lysophosphatidylcholine cotransporter that plays an important role in maintaining the integrity of the blood-brain barrier and neurological function. Abnormal degradation of Mfsd2a often leads to dysfunction of the blood-brain barrier, while upregulation of Mfsd2a can retrieve neurological damage. It has been reported that Mfsd2a can be specifically recognized and ubiquitinated by neural precursor cell-expressed developmentally downregulated gene 4 type 2 (NEDD4-2) ubiquitin ligase and finally degraded through the proteasome pathway. However, the structural basis for the specific binding of Mfsd2a to NEDD4-2 is unclear. In this work, we combined deep learning and molecular dynamics simulations to obtain a Mfsd2a structure with high quality and a stable Mfsd2a/NEDD4-2-WW3 interaction model. Moreover, molecular mechanics generalized Born surface area (MM-GBSA) methods coupled with per-residue energy decomposition studies were carried out to analyze the key residues that dominate the binding interaction. Based on these results, we designed three peptides containing the key residues by truncating the Mfsd2a sequences. One of them was found to significantly inhibit Mfsd2a ubiquitination, which was further validated in an oxygen-glucose deprivation (OGD) model in a human microvascular endothelial cell line. This work provides some new insights into the understanding of Mfsd2a and NEDD4-2 interaction and might promote further development of drugs targeting Mfsd2a ubiquitination.

Matrix Metalloproteinase-9 inhibitors as therapeutic drugs for traumatic brain injury

Traumatic brain injury (TBI) is one of the leading causes of morbidity and mortality among young adults and the elderly. In the United States, TBI is responsible for around 30 percent of all injuries brought on by injuries in general. Vasogenic cerebral edema due to blood-brain barrier (BBB) dysfunction and the associated elevation of intracranial pressure (ICP) are some of the major causes of secondary injuries following traumatic brain injury. Matrix metalloproteinase-9 (MMP-9) is a therapeutic target for being an enzyme that degrades the proteins that make up a part of the microvascular basal lamina as well as inter-endothelial tight junctions of the blood-brain barrier. MMP-9-mediated BBB dysfunctions and the compromise of the BBB is a major pathway that leads the development of vasogenic cerebral edema, elevation of ICP, poor cerebral perfusion and brain herniation following traumatic brain injury. That makes MMP-9 an effective therapeutic target and endogenous or exogenous MMP-9 inhibitors as therapeutic drugs for preventing secondary brain damage after traumatic brain injury. Although our understanding of the mechanisms that underlie the primary and secondary stages of damage following a TBI has significantly improved in recent years, such information has not yet resulted in the successful development of novel pharmacological treatment options for traumatic brain injury. Recent pre-clinical and/or clinical studies have demonstrated that there are several compounds with specific or non-specific MMP-9 inhibitory properties either directly binding and inhibiting MMP-9 or by indirectly inhibiting MMP-9, with potential as therapeutic agents for traumatic brain injury. This article reviews the efficacy of several such medications and potential agents that include endogenous and exogeneous compounds that are at various levels of research and development. MMP-9-based therapeutic drug development has enormous potential in the pharmacological treatment of cerebral edema and/or neuronal injury resulting from traumatic brain injury.

Role of regulatory non-coding RNAs in traumatic brain injury

Traumatic brain injury (TBI) is a potentially fatal health event that cannot be predicted in advance. After TBI occurs, it can have enduring consequences within both familial and social spheres. Yet, despite extensive efforts to improve medical interventions and tailor healthcare services, TBI still remains a major contributor to global disability and mortality rates. The prompt and accurate diagnosis of TBI in clinical contexts, coupled with the implementation of effective therapeutic strategies, remains an arduous challenge. However, a deeper understanding of changes in gene expression and the underlying molecular regulatory processes may alleviate this pressing issue. In recent years, the study of regulatory non-coding RNAs (ncRNAs), a diverse class of RNA molecules with regulatory functions, has been a potential game changer in TBI research. Notably, the identification of microRNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and other ncRNAs has revealed their potential as novel diagnostic biomarkers and therapeutic targets for TBI, owing to their ability to regulate the expression of numerous genes. In this review, we seek to provide a comprehensive overview of the functions of regulatory ncRNAs in TBI. We also summarize regulatory ncRNAs used for treatment in animal models, as well as miRNAs, lncRNAs, and circRNAs that served as biomarkers for TBI diagnosis and prognosis. Finally, we discuss future challenges and prospects in diagnosing and treating TBI patients in the clinical settings.

Drug Discovery Research for Traumatic Brain Injury Focused on Functional Molecules in Astrocytes

Traumatic brain injury (TBI) is severe damage to the head caused by traffic accidents, falls, and sports. Because TBI-induced disruption of the blood-brain barrier (BBB) causes brain edema and neuroinflammation, which are major causes of death or serious disabilities, protection and recovery of BBB function may be beneficial therapeutic strategies for TBI. Astrocytes are key components of BBB integrity, and astrocyte-derived bioactive factors promote and suppress BBB disruption in TBI. Therefore, the regulation of astrocyte function is essential for BBB protection. In the injured cerebrum of TBI model mice, we found that the endothelin ETB receptor, histamine H2 receptor, and transient receptor potential vanilloid 4 (TRPV4) were predominantly expressed in reactive astrocytes. We also showed that repeated administration of an ETB receptor antagonist, H2 receptor agonist, and TRPV4 antagonist alleviated BBB disruption and brain edema in a TBI mouse model. Furthermore, these drugs decreased the expression levels of astrocyte-derived factors promoting BBB disruption and increased the expression levels of astrocyte-derived protective factors in the injured cerebrum after TBI. These results suggest that the ETB receptor, H2 receptor, and TRPV4 are molecules that regulate astrocyte function, and might be attractive candidates for the development of therapeutic drugs for TBI.

Mannitol inhibits the proliferation of neural stem cell by a p38 mitogen-activated protein kinase-dependent signaling pathway

PURPOSE

Mannitol is one of the first-line drugs for reducing cerebral edema through increasing the extracellular osmotic pressure. However, long-term administration of mannitol in the treatment of cerebral edema triggers damage to neurons and astrocytes. Given that neural stem cell (NSC) is a subpopulation of main regenerative cells in the central nervous system after injury, the effect of mannitol on NSC is still elusive. The present study aims to elucidate the role of mannitol in NSC proliferation.

METHODS

C57 mice were derived from the animal house of Zunyi Medical University. A total of 15 pregnant mice were employed for the purpose of isolating NSCs in this investigation. Initially, mouse primary NSCs were isolated from the embryonic cortex of mice and subsequently identified through immunofluorescence staining. In order to investigate the impact of mannitol on NSC proliferation, both cell counting kit-8 assays and neurospheres formation assays were conducted. The in vitro effects of mannitol were examined at various doses and time points. In order to elucidate the role of Aquaporin 4 (AQP4) in the suppressive effect of mannitol on NSC proliferation, various assays including reverse transcription polymerase chain reaction, western blotting, and immunocytochemistry were conducted on control and mannitol-treated groups. Additionally, the phosphorylated p38 (p-p38) was examined to explore the potential mechanism underlying the inhibitory effect of mannitol on NSC proliferation. Finally, to further confirm the involvement of the p38 mitogen-activated protein kinase-dependent (MAPK) signaling pathway in the observed inhibition of NSC proliferation by mannitol, SB203580 was employed. All data were analyzed using SPSS 20.0 software (SPSS, Inc., Chicago, IL). The statistical analysis among multiple comparisons was performed using one-way analysis of variance (ANOVA), followed by Turkey's post hoc test in case of the data following a normal distribution using a Shapiro-Wilk normality test. Comparisons between 2 groups were determined using Student's t-test, if the data exhibited a normal distribution using a Shapiro-Wilk normality test. Meanwhile, data were shown as median and interquartile range and analyzed using the Mann-Whitney U test, if the data failed the normality test. A p < 0.05 was considered as significant difference.

RESULTS

Primary NSC were isolated from the mice, and the characteristics were identified using immunostaining analysis. Thereafter, the results indicated that mannitol held the capability of inhibiting NSC proliferation in a dose-dependent and time-dependent manner using cell counting kit-8, neurospheres formation, and immunostaining of Nestin and Ki67 assays. During the process of mannitol suppressing NSC proliferation, the expression of AQP4 mRNA and protein was downregulated, while the gene expression of p-p38 was elevated by reverse transcription polymerase chain reaction, immunostaining, and western blotting assays. Subsequently, the administration of SB203580, one of the p38 MAPK signaling pathway inhibitors, partially abrogated this inhibitory effect resulting from mannitol, supporting the fact that the p38 MAPK signaling pathway participated in curbing NSC proliferation induced by mannitol.

CONCLUSIONS

Mannitol inhibits NSC proliferation through downregulating AQP4, while upregulating the expression of p-p38 MAPK.

Prednisolone Targets Claudins in Mouse Brain Blood Vessels

Endothelial cells in brain capillaries are crucial for the function of the blood-brain barrier (BBB), and members of the tight junction protein family of claudins are regarded to be primarily responsible for barrier properties. Thus, the analysis of bioactive substances that can affect the BBB's permeability is of great importance and may be useful for the development of new therapeutic strategies for brain pathologies. In our study, we tested the hypothesis that the application of the glucocorticoid prednisolone affects the murine blood-brain barrier in vivo. Isolated brain tissue of control and prednisolone-injected mice was examined by employing immunoblotting and confocal laser scanning immunofluorescence microscopy, and the physiological and behavioral effects were analyzed. The control tissue samples revealed the expression of barrier-forming tight junction proteins claudin-1, -3, and -5 and of the paracellular cation and water-channel-forming protein claudin-2. Prednisolone administration for 7 days at doses of 70 mg/kg caused physiological and behavioral effects and downregulated claudin-1 and -3 and the channel-forming claudin-2 without altering their localization in cerebral blood vessels. Changes in the expression of these claudins might have effects on the ionic and acid-base balance in brain tissue, suggesting the relevance of our findings for therapeutic options in disorders such as cerebral edema and psychiatric failure.

Increased brain age and relationships with blood-based biomarkers following concussion in younger populations

OBJECTIVE

Brain age is increasingly being applied to the spectrum of brain injury to define neuropathological changes in conjunction with blood-based biomarkers. However, data from the acute/sub-acute stages of concussion are lacking, especially among younger cohorts.

METHODS

Predicted brain age differences were independently calculated in large, prospectively recruited cohorts of pediatric concussion and matched healthy controls (total N = 446), as well as collegiate athletes with sport-related concussion and matched non-contact sport controls (total N = 184). Effects of repetitive head injury (i.e., exposure) were examined in a separate cohort of contact sport athletes (N = 82), as well as by quantifying concussion history through semi-structured interviews and years of contact sport participation.

RESULTS

Findings of increased brain age during acute and sub-acute concussion were independently replicated across both cohorts, with stronger evidence of recovery for pediatric (4 months) relative to concussed athletes (6 months). Mixed evidence existed for effects of repetitive head injury, as brain age was increased in contact sport athletes, but was not associated with concussion history or years of contact sport exposure. There was no difference in brain age between concussed and contact sport athletes. Total tau decreased immediately (~ 1.5 days) post-concussion relative to the non-contact group, whereas pro-inflammatory markers were increased in both concussed and contact sport athletes. Anti-inflammatory markers were inversely related to brain age, whereas markers of axonal injury (neurofilament light) exhibited a trend positive association.

CONCLUSION

Current and previous findings collectively suggest that the chronicity of brain age differences may be mediated by age at injury (adults > children), with preliminary findings suggesting that exposure to contact sports may also increase brain age.

Anacardic acid improves neurological deficits in traumatic brain injury by anti-ferroptosis and anti-inflammation

BACKGROUND

Traumatic brain injury (TBI) is an important cause of disability and death. TBI leads to multiple forms of nerve cell death including ferroptosis due to iron-dependent lipid peroxidation. Anacardic acid (AA) is a natural component extracted from cashew nut shells, which has been reported to have neuroprotective effects in traumatic brain injury. We investigated whether AA has an anti-ferroptosis effect in TBI.

METHODS

We used the Feeney free-fall impact method to construct a TBI model to investigate the effect of AA on ferroptosis caused by TBI, in which Ferrostatin-1 (Fer-1), a ferroptosis inhibitor, served as a positive control group. We first identified the therapeutic effect of AA on TBI through modified neurological severity score (mNSS) and determined the appropriate concentration. Secondly, we investigated the effect of AA on the expression level of the key protein of ferroptosis by Western blotting and immunohistochemistry. Then the effect of AA on nerve tissue injury and nerve function improvement was verified. Finally, enzym-linked immunosorbent assay (ELISA) was used to verify that AA could reduce inflammation after TBI.

RESULTS

We found the intensely inhibitory effect of AA on ferroptosis, which is in parallel with the results obtained after Fer-1 treatment. In addition, AA and Fer-1 mitigated TBI-mediated tissue defects, destruction of the blood-brain barrier, and neurodegeneration. Novel object recognition (NOR), mNSS and water maze test showed that AA could significantly reduce the impairment of neural function and behavioral cognitive ability caused by TBI. Finally, we also demonstrated that AA has not only an anti-ferroptosis effect, but also an anti-inflammation effect.

CONCLUSIONS

AA can reduce the neurological impairment and behavioral cognitive impairment caused by TBI through the dual effect of anti-ferroptosis and anti-inflammation.

P2Y12 receptor mediates apoptosis and demyelination to affect functional recovery in mice with spinal cord injury

Among diseases of the central nervous system (CNS), spinal cord injury (SCI) has a high fatality rate. It has been proven that P2Y G protein-coupled purinergic receptors have a neuroprotective role in apoptosis and regeneration inside the damaged spinal cord. The P2Y12 receptor (P2Y12R) has recently been linked to peripheral neuropathy and stroke. However, the role of P2Y12R after SCI remains unclear. Our study randomly divided C57BL/6J female mice into 3 groups: Sham+DMSO, SCI+DMSO, and SCI+MRS2395. MRS2395 as a P2Y12R inhibitor was intraperitoneally injected at a dose of 1.5 mg/kg once daily for 7 days. We showed that the P2Y12R was markedly activated after injury, and it was double labeled with the microglial and neuron. Behavioral tests were employed to assess motor function recovery. By using immunofluorescence staining, the NeuN expression level was detected. The morphology of neurons was observed by hematoxylin-eosin and Nissl staining. P2Y12R, Bax, GFAP, PCNA and calbindin expression levels were detected using Western blot. Meanwhile, mitochondria and myelin sheath were observed by transmission electron microscopy (TEM). Our findings demonstrated that MRS2395 significantly enhanced motor function induced by SCI and that was used to alleviate apoptosis and astrocyte scarring. NeuN positive cells in the SCI group were lower than in the therapy group, although Bax, GFAP, PCNA and calbindin expression levels were considerably higher. Moreover, following MRS2395 therapy, the histological damage was reversed. A notable improvement in myelin sheath and mitochondrial morphology was seen in the therapy group. Together, our findings indicate that activation of P2Y12R in damaged spinal cord may be a critical event and suggest that inhibition of P2Y12R might be a feasible therapeutic strategy for treating SCI.

Prolonged course of brain edema and neurological recovery in a translational model of decompressive craniectomy after closed head injury in mice

Background

The use of decompressive craniectomy in traumatic brain injury (TBI) remains a matter of debate. According to the DECRA trial, craniectomy may have a negative impact on functional outcome, while the RescueICP trial revealed a positive effect of surgical decompression, which is evolving over time. This ambivalence of craniectomy has not been studied extensively in controlled laboratory experiments.

Objective

The goal of the current study was to investigate the prolonged effects of decompressive craniectomy (both positive and negative) in an animal model.

Methods

Male mice were assigned to the following groups: sham, decompressive craniectomy, TBI and TBI followed by craniectomy. The analysis of functional outcome was performed at time points 3d, 7d, 14d and 28d post trauma according to the Neurological Severity Score and Beam Balance Score. At the same time points, magnetic resonance imaging was performed, and brain edema was analyzed.

Results

Animals subjected to both trauma and craniectomy presented the exacerbation of the neurological impairment that was apparent mostly in the early course (up to 7d) after injury. Decompressive craniectomy also caused a significant increase in brain edema volume (initially cytotoxic with a secondary shift to vasogenic edema and gliosis). Notably, delayed edema plus gliosis appeared also after decompression even without preceding trauma.

Conclusion

In prolonged outcomes, craniectomy applied after closed head injury in mice aggravates posttraumatic brain edema, leading to additional functional impairment. This effect is, however, transient. Treatment options that reduce brain swelling after decompression may accelerate neurological recovery and should be explored in future experiments.

The risk and outcome of malignant brain edema in post-mechanical thrombectomy: acute ischemic stroke by anterior circulation occlusion

BACKGROUND AND PURPOSE

Malignant brain edema (MBE) occurring after mechanical thrombectomy (MT) in acute ischemic stroke (AIS) could lead to severe disability and mortality. We aimed to investigate the incidence, predictors, and clinical outcomes of MBE in patients with AIS after MT.

METHODS

The clinical and imaging data of 155 patients with AIS of anterior circulation after MT were studied. Standard non-contrast CT was used to evaluate baseline imaging characteristics at admission. Clinical outcomes were measured using the 90-day modified Rankin Scale (mRS) score. Based on the follow-up CT scans performed within 72 h after MT, the patients were classified into MBE and non-MBE group. MBE was defined as a midline shift of ≥ 5 mm with signs of local brain swelling. Univariate and multivariate regression analyses were used to analyze the relationship between MBE and clinical outcomes and identify the predictors that correlate with MBE.

RESULTS

MBE was observed in 19.4% of the patients who underwent MT and was associated with a lower rate of favorable 90-day clinical outcomes. Significant differences were observed in both MBE and non-MBE groups: baseline Alberta Stroke Program Early CT (ASPECT) score, hyperdense middle cerebral artery sign (HMCAS), baseline signs of early infarct, angiographic favorable collaterals, number of retrieval attempts, and revascularization rate. Multivariate analysis indicated that low baseline ASPECT score, absent HMCAS, angiographic poor collaterals, more retrieval attempt count, and poor revascularization independently influenced the occurrence of MBE in AIS patients with anterior circulation after MT.

CONCLUSION

MBE was associated with a lower rate of favorable 90-day clinical outcomes. Low baseline ASPECT score, absent HMCAS, angiographic poor collaterals, more retrieval attempt count and poor revascularization were independently associated with MBE after MT.

The Renin Angiotensin System as a Therapeutic Target in Traumatic Brain Injury

Traumatic brain injury (TBI) is a major public health problem, with limited pharmacological options available beyond symptomatic relief. The renin angiotensin system (RAS) is primarily known as a systemic endocrine regulatory system, with major roles controlling blood pressure and fluid homeostasis. Drugs that target the RAS are used to treat hypertension, heart failure and kidney disorders. They have now been used chronically by millions of people and have a favorable safety profile. In addition to the systemic RAS, it is now appreciated that many different organ systems, including the brain, have their own local RAS. The major ligand of the classic RAS, Angiotensin II (Ang II) acts predominantly through the Ang II Type 1 receptor (AT1R), leading to vasoconstriction, inflammation, and heightened oxidative stress. These processes can exacerbate brain injuries. Ang II receptor blockers (ARBs) are AT1R antagonists. They have been shown in several preclinical studies to enhance recovery from TBI in rodents through improvements in molecular, cellular and behavioral correlates of injury. ARBs are now under consideration for clinical trials in TBI. Several different RAS peptides that signal through receptors distinct from the AT1R, are also potential therapeutic targets for TBI. The counter regulatory RAS pathway has actions that oppose those stimulated by AT1R signaling. This alternative pathway has many beneficial effects on cells in the central nervous system, bringing about vasodilation, and having anti-inflammatory and anti-oxidative stress actions. Stimulation of this pathway also has potential therapeutic value for the treatment of TBI. This comprehensive review will provide an overview of the various components of the RAS, with a focus on their direct relevance to TBI pathology. It will explore different therapeutic agents that modulate this system and assess their potential efficacy in treating TBI patients.

Advancing edema detection: Harnessing the power of machine learning and near infrared spectroscopy for cerebral and cerebellar edema assessment

Edema, characterized by brain swelling, is a common response observed in various brain injuries. Timely detection of edema is crucial to mitigate the associated risks and improve patient care. This study evaluates the efficacy of CEREBO®, a non-invasive machine learning-powered near-infrared spectroscopy (mNIRS) based device, in detecting edema. The study was conducted on 234 participants with suspected head injuries who underwent simultaneous CEREBO® scans and CT head scans. The results of the study showed that CEREBO® effectively identified edematous lobes, achieving a sensitivity of 95.7%, specificity of 97%, and accuracy of 96.9% for cases with intracranial hemorrhage (ICH). Additionally, for cases without ICH, the device exhibited a sensitivity of 100%, specificity of 97.2%, and accuracy of 97.2%. Two cases were reported where CEREBO® failed to detect edematous ICH. The study highlights the potential of CEREBO® as a valuable tool for early detection of pre-symptomatic edema and ICH, enabling timely interventions and improved patient care. The findings support the reliability of near-infrared spectroscopy as a diagnostic modality for edema.

The Role of Inhaled Estradiol and Myrtenol, Alone and in Combination, in Modulating Behavioral and Functional Outcomes Following Traumatic Experimental Brain Injury: Hemodynamic, Molecular, Histological and Behavioral Study

BACKGROUND

Traumatic brain injury (TBI) is an important and growing cause of disability worldwide, and its cognitive consequences may be particularly significant. This study assessed the neuroprotective impacts of estradiol (E2), myrtenol (Myr), and the combination of the two on the neurological outcome, hemodynamic parameters, learning and memory, brain-derived neurotrophic factor (BDNF) level, phosphoinositide 3-kinases (PI3K/AKT) signaling, and inflammatory and oxidative factors in the hippocampus after TBI.

METHODS

Eighty-four adult male Wistar rats were randomly divided into 12 groups with seven rats in each (six groups to measure intracranial pressure, cerebral perfusion pressure, brain water content, and veterinary coma scale, and six groups for behavioral and molecular studies): sham, TBI, TBI/vehicle, TBI/Myr, TBI/E2, and TBI/Myr + E2 (Myr 50 mg/kg and E2 33.3 μg/kg via inhalation for 30 min after TBI induction). Brain injury was induced by using Marmarou's method. Briefly, a 300-g weight was dropped down from a 2-m height through a free-falling tube onto the head of the anesthetized animals.

RESULTS

Veterinary coma scale, learning and memory, brain water content, intracranial pressure, and cerebral perfusion pressure were impaired following TBI, and inflammation and oxidative stress were raised in the hippocampus after TBI. The BDNF level and PI3K/AKT signaling were impaired due to TBI. Inhalation of Myr and E2 had protective effects against all negative consequences of TBI by decreasing brain edema and the hippocampal content of inflammatory and oxidant factors and also by improving BDNF and PI3K/AKT in the hippocampus. Based on these data, there were no differences between alone and combination administrations.

CONCLUSIONS

Our results propose that Myr and E2 have neuroprotective effects on cognition impairments due to TBI.

Zinc defends against Parthanatos and promotes functional recovery after spinal cord injury through SIRT3-mediated anti-oxidative stress and mitophagy

INTRODUCTION

Spinal cord injury (SCI) is a central nervous system injury that is primarily traumatic and manifests as motor, sensory, and autonomic dysfunction below the level of damage. Our previous studies confirmed the ability of zinc to protect mitochondria, protect neurons and promote spinal cord recovery. However, the role of zinc in Parthanatos is unknown.

AIM

We investigated the effects of zinc in Parthanatos from oxidative stress and mitophagy. We elucidated the role of SIRT3 in providing new ideas for treating spinal cord injury.

THE RESULTS

Zinc protected SCI mice by regulating Parthanatos. On the one hand, zinc eliminated ROS directly through SIRT3 deacetylation targeting SOD2 to alleviate Parthanatos. On the other hand, zinc eliminated ROS indirectly through SIRT3-mediated promotion of mitophagy to alleviate Parthanatos.

CONCLUSION

Zinc defends against Parthanatos and promotes functional recovery after spinal cord injury through SIRT3-mediated anti-oxidative stress and mitophagy.

Epidemiology and Outcomes of Cerebral Edema in Hospitalized Children

BACKGROUND

Cerebral edema can be a consequence of multiple disease processes. Untreated cerebral edema can be fatal, and even with aggressive management, it can be devastating. The objective of this study was to describe the prevalence, underlying causes, and outcomes of cerebral edema in hospitalized children.

METHODS

A retrospective cross-sectional study using the 2016 Kids' Inpatient Database was performed. Children aged one month to 20 years were included. Sample weighting was employed to produce national estimates. Univariate analyses were used to compare those who died and survived. Multivariable logistic regression was performed to assess the influence of demographic variables and etiologic factors on mortality.

RESULTS

Cerebral edema was documented in 4903 children of 2,210,263 (2.2 of 1000) discharges. Among children with cerebral edema, males were 57%, white children were 47.9%, and adolescents were 48.9%. The three most common etiologies associated with cerebral edema in this cohort were stroke (21.7%), anoxic injury (21.4%), and central nervous system (CNS) malignancy (16%). The overall hospital mortality rate was 29.4%. The adjusted mortality rate was significantly higher when cerebral edema was associated with anoxic injury (84%). The mortality was lower when cerebral edema was associated with CNS malignancy (9.5%) or diabetic ketoacidosis (DKA) (4.3%).

CONCLUSIONS

Cerebral edema is uncommon in hospitalized children but has a high mortality. Stroke and anoxic brain injury are the two most common etiologies for cerebral edema in hospitalized children in the United States. Among all etiologies for cerebral edema in children, anoxic brain injury has the highest mortality, whereas DKA has the lowest mortality.

Glibenclamide for Brain Contusions: Contextualizing a Promising Clinical Trial Design that Leverages an Imaging-Based TBI Endotype

TBI heterogeneity is recognized as a major impediment to successful translation of therapies that could improve morbidity and mortality after injury. This heterogeneity exists on multiple levels including primary injury, secondary injury/host-response, and recovery. One widely accepted type of primary-injury related heterogeneity is pathoanatomic-the intracranial compartment that is predominantly affected, which can include any combination of subdural, subarachnoid, intraparenchymal, diffuse axonal, intraventricular and epidural hemorrhages. Intraparenchymal contusions carry the highest risk for progression. Contusion expansion is one of the most important drivers of death and disability after TBI. Over the past decade, there has been increasing evidence of the role of the sulfonylurea-receptor 1-transient receptor potential melastatin 4 (SUR1-TRPM4) channel in secondary injury after TBI, including progression of both cerebral edema and intraparenchymal hemorrhage. Inhibition of SUR1-TRPM4 with glibenclamide has shown promising results in preclinical models of contusional TBI with benefits against cerebral edema, secondary hemorrhage progression of the contusion, and improved functional outcome. Early-stage human research supports the key role of this pathway in contusion expansion and suggests a benefit with glibenclamide inhibition. ASTRAL is an ongoing international multi-center double blind multidose placebo-controlled phase-II clinical trial evaluating the safety and efficacy of an intravenous formulation of glibenclamide (BIIB093). ASTRAL is a unique and innovative study that addresses TBI heterogeneity by limiting enrollment to patients with the TBI pathoanatomic endotype of brain contusion and using contusion-expansion (a mechanistically linked secondary injury) as its primary outcome. Both criteria are consistent with the strong supporting preclinical and molecular data. In this narrative review, we contextualize the development and design of ASTRAL, including the need to address TBI heterogeneity, the scientific rationale underlying the focus on brain contusions and contusion-expansion, and the preclinical and clinical data supporting benefit of SUR1-TRPM4 inhibition in this specific endotype. Within this framework, we summarize the current study design of ASTRAL which is sponsored by Biogen and actively enrolling with a goal of 160 participants.

Intranasal Insulin Alleviates Traumatic Brain Injury by Inhibiting Autophagy and Endoplasmic Reticulum Stress-mediated Apoptosis Through the PI3K/Akt/mTOR Signaling Pathway

Intranasal insulin reduces lesion size and enhances memory capacity in traumatic brain injury (TBI) models, but the molecular mechanisms behind this neuroprotective action not yet understood. Here we used Feeney's free-falling method to construct TBI mouse models and administrated intranasal insulin, rapamycin, insulin and rapamycin, or normal saline to assess their effects on neurological functions, cerebral edema, and the expression of Iba1 in microglia through immunofluorescence assay. We also measured concentrations of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the brain using enzyme immunosorbent assay, investigated apoptosis with TUNEL staining and Western blotting, and evaluated autophagy, endoplasmic reticulum (ER) stress, and PI3K/Akt/mTOR signaling pathway with Western blotting. The autophagosome was assessed through transmission electron microscopy. Our findings demonstrated that intranasal insulin promoted neurological recovery, decreased brain swelling, and reduced injury lesions on days 1, 3, and 7 post TBI. Moreover, intranasal insulin reduced microglia activation and the concentration of IL-1β or TNF-α on the same days. Through Western blotting and transmission electron microscopy, we observed that intranasal insulin suppressed autophagy while activating the PI3K/AKT/mTOR signaling pathway on days 1 and 3 post TBI. TUNEL assay and Western blotting also indicated that intranasal insulin inhibited ER stress-mediated apoptosis. Interestingly, the mTOR inhibitor rapamycin partially blocked the pro-autophagy and anti-apoptosis effects of intranasal insulin both on days 1 and 3 post TBI. Our results suggest that intranasal insulin can ameliorate TBI by regulating autophagy and ER stress-mediated apoptosis through the PI3K/AKT/mTOR signaling pathway, providing a promising therapeutic strategy for TBI.

Effect of thymosin β4 on lipopolysaccharide‑stimulated brain microvascular endothelial cell remodeling: A possible role in blood‑brain barrier injury

War veterans, in particular, are more prone to mental illness as they are more likely to have encountered multiple traumatic brain injuries (TBIs) whilst serving on active duty in war zone areas. A TBI is known to cause mortality or serious neurological disabilities among survivors and elicits a number of pathological processes, including neuroinflammation and blood brain barrier (BBB) disruption, leading to secondary brain damage and subsequent impairment of the neurovascular unit. Although several drugs exhibit promising effects for TBI, the repertoire of currently available therapeutic strategies remains limited. Thymosin 4 (Tβ4) is a 43-amino acid G-acting sequestering peptide that confers neuroprotective potential in TBI models. However, its role in BBB function remains unclear. Further research into the mechanism of BBB disruption induced by TBI and its specific role in neurovascular pathophysiology is necessary. In the present study, the protective effects of Tβ4 in lipopolysaccharide (LPS)-stimulated gene expression of several tight junction proteins, inflammatory genes, apoptotic genes, and adhesion genes in human brain microvascular endothelial cells (hBMVECs), one of the pivotal cell types in the BBB, were reported. The results suggested that pretreatment with Tβ4 reversed the LPS-induced damage of BBB components in hBMVECs. Furthermore, these results identified neuregulin 1 as a possible target for Tβ4. Therefore, it is proposed that Tβ4-mediated cellular signaling in hBMVEC may be vital for understanding the association between the BBB and TBI pathophysiology, which warrants further investigation.