The Importance of Therapeutic Time Window in the Treatment of Traumatic Brain Injury

Dose-Dependent Tranexamic Acid Blunting of Penumbral Leukocyte Mobilization and Blood-Brain Barrier Permeability Following Traumatic Brain Injury: An In Vivo Murine Study

BACKGROUND

Early posttraumatic brain injury (TBI) tranexamic acid (TXA) may reduce blood-brain barrier (BBB) permeability, but it is unclear if this effect is fixed regardless of dose. We hypothesized that post-TBI TXA demonstrates a dose-dependent reduction of in vivo penumbral leukocyte mobilization, BBB microvascular permeability, and enhancement of neuroclinical recovery.

METHODS

CD1 male mice (n = 40) were randomly assigned to TBI by controlled cortical impact (injury [I]) or sham TBI (S), followed by intravenous bolus of either saline (placebo [P]) or TXA (15, 30, or 60 mg/kg). At 48 h, in vivo pial intravital microscopy visualized live penumbral BBB microvascular leukocytes and albumin leakage. Neuroclinical recovery was assessed by Garcia Neurological Test scores and animal weight changes at 24 h and 48 h after injury.

RESULTS

I + TXA60 reduced live penumbral leukocyte rolling compared with I + P (p < 0.001) and both lower TXA doses (p = 0.017 vs. I + TXA15, p = 0.012 vs. I + TXA30). Leukocyte adhesion was infrequent and similar across groups. Only I + TXA60 significantly reduced BBB permeability compared with that in the I + P (p = 0.004) group. All TXA doses improved Garcia Test scores relative to I + P at both 24 h and 48 h (p < 0.001 vs. I + P for all at both time points). Mean 24-h body weight loss was greatest in the I + P (- 8.7 ± 1.3%) group and lowest in the I + TXA15 (- 4.4 ± 1.0%, p = 0.051 vs. I + P) group.

CONCLUSIONS

Only higher TXA dosing definitively abrogates penumbral leukocyte mobilization, preserving BBB integrity post TBI. Some neuroclinical recovery is observed, even with lower TXA dosing. Better outcomes with higher dose TXA after TBI may occur secondary to blunting of leukocyte-mediated penumbral cerebrovascular inflammation.

mGlu4R, mGlu7R, and mGlu8R allosteric modulation for treating acute and chronic neurodegenerative disorders

Neuroprotection, defined as safeguarding neurons from damage and death by inhibiting diverse pathological mechanisms, continues to be a promising approach for managing a range of central nervous system (CNS) disorders, including acute conditions such as ischemic stroke and traumatic brain injury (TBI) and chronic neurodegenerative diseases like Parkinson's disease (PD), Alzheimer's disease (AD), and multiple sclerosis (MS). These pathophysiological conditions involve excessive glutamatergic (Glu) transmission activity, which can lead to excitotoxicity. Inhibiting this excessive Glu transmission has been proposed as a potential therapeutic strategy for treating the CNS disorders mentioned. In particular, ligands of G protein-coupled receptors (GPCRs), including metabotropic glutamatergic receptors (mGluRs), have been recognized as promising options for inhibiting excessive Glu transmission. This review discusses the complex interactions of mGlu receptors with their subtypes, including the formation of homo- and heterodimers, which may vary in function and pharmacology depending on their protomer composition. Understanding these intricate details of mGlu receptor structure and function enhances researchers' ability to develop targeted pharmacological interventions, potentially offering new therapeutic avenues for neurological and psychiatric disorders. This review also summarizes the current knowledge of the neuroprotective potential of ligands targeting group III mGluRs in preclinical cellular (in vitro) and animal (in vivo) models of ischemic stroke, TBI, PD, AD, and MS. In recent years, experiments have shown that compounds, especially those activating mGlu4 or mGlu7 receptors, exhibit protective effects in experimental ischemia models. The discovery of allosteric ligands for specific mGluR subtypes has led to reports suggesting that group III mGluRs may be promising targets for neuroprotective therapy in PD (mGlu4R), TBI (mGlu7R), and MS (mGlu8R).

Development of a Quality Indicator Set for the Optimal Acute Management of Moderate to Severe Traumatic Brain Injury in the Australian Context

BACKGROUND

The aim of this study was to develop a consensus-based set of indicators of high-quality acute moderate to severe traumatic brain injury (msTBI) clinical management that can be used to measure structure, process, and outcome factors that are likely to influence patient outcomes. This is the first stage of the PRECISION-TBI program, which is a prospective cohort study that aims to identify and promote optimal clinical management of msTBI in Australia.

METHODS

A preliminary set of 45 quality indicators was developed based on available evidence. An advisory committee of established experts in the field refined the initial indicator set in terms of content coverage, proportional representation, contamination, and supporting evidence. The refined indicator set was then distributed to a wider Delphi panel for assessment of each indicator in terms of validity, measurement feasibility, variability, and action feasibility. Inclusion in the final indicator set was contingent on prespecified inclusion scoring.

RESULTS

The indicator set was structured according to the care pathway of msTBI and included prehospital, emergency department, neurosurgical, intensive care, and rehabilitation indicators. Measurement domains included structure indicators, logistic indicators, and clinical management indicators. The Delphi panel consisted of 44 participants (84% physician, 12% nursing, and 4% primary research) with a median of 15 years of practice. Of the 47 indicators included in the second round of the Delphi, 32 indicators were approved by the Delphi group.

CONCLUSIONS

This study identified a set of 32 quality indicators that can be used to structure data collection to drive quality improvement in the clinical management of msTBI. They will also be used to guide feedback to PRECISION-TBI's participating sites.

Brain tissue oxygen monitoring in moderate-to-severe traumatic brain injury: Physiological determinants, clinical interventions and current randomised controlled trial evidence

Modern intensive care for moderate-to-severe traumatic brain injury (msTBI) focuses on managing intracranial pressure (ICP) and cerebral perfusion pressure (CPP). This approach lacks robust clinical evidence and often overlooks the impact of hypoxic injuries. Emerging monitoring modalities, particularly those capable of measuring brain tissue oxygen, represent a promising avenue for advanced neuromonitoring. Among these, brain tissue oxygen tension (PbtO2) shows the most promising results. However, there is still a lack of consensus regarding the interpretation of PbtO2 in clinical practice. This review aims to provide an overview of the pathophysiological rationales, monitoring technology, physiological determinants, and recent clinical trial evidence for PbtO2 monitoring in the management of msTBI.

Reprograming Clots for In Vivo Chemical Targeting in Traumatic Brain Injury

Traumatic brain injury (TBI) is a critical public health concern, yet there are no therapeutics available to improve long-term outcomes. Drug delivery to TBI remains a challenge due to the blood-brain barrier and increased intracranial pressure. In this work, a chemical targeting approach to improve delivery of materials to the injured brain, is developed. It is hypothesized that the provisional fibrin matrix can be harnessed as an injury-specific scaffold that can be targeted by materials via click chemistry. To accomplish this, the brain clot is engineered in situ by delivering fibrinogen modified with strained cyclooctyne (SCO) moieties, which incorporated into the injury lesion and is retained there for days. Improved intra-injury capture and retention of diverse, clickable azide-materials including a small molecule azide-dye, 40 kDa azide-PEG nanomaterial, and a therapeutic azide-protein in multiple dosing regimens is subsequently observed. To demonstrate therapeutic translation of this approach, a reduction in reactive oxygen species levels in the injured brain after delivery of the antioxidant catalase, is achieved. Further, colocalization between azide and SCO-fibrinogen is specific to the brain over off-target organs. Taken together, a chemical targeting strategy leveraging endogenous clot formation is established which can be applied to improve therapeutic delivery after TBI.

Utility of Early Magnetic Resonance Imaging to Enhance Outcome Prediction in Critically Ill Children with Severe Traumatic Brain Injury

BACKGROUND

Many children with severe traumatic brain injury (TBI) receive magnetic resonance imaging (MRI) during hospitalization. There are insufficient data on how different patterns of injury on early MRI inform outcomes.

METHODS

Children (3-17 years) admitted in 2010-2021 for severe TBI (Glasgow Coma Scale [GCS] score < 9) were identified using our site's trauma registry. We used multivariable modeling to determine whether the hemorrhagic diffuse axonal injury (DAI) grade and the number of regions with restricted diffusion (subcortical white matter, corpus callosum, deep gray matter, and brainstem) on MRI obtained within 7 days of injury were independently associated with time to follow commands and with Functional Independence Measure for Children (WeeFIM) scores at the time of discharge from inpatient rehabilitation. We controlled for the clinical variables age, preadmission cardiopulmonary resuscitation, pupil reactivity, motor GCS score, and fever (> 38 °C) in the first 12 h.

RESULTS

Of 260 patients, 136 (52%) underwent MRI within 7 days of injury at a median of 3 days (interquartile range [IQR] 2-4). Patients with early MRI were a median age of 11 years (IQR 7-14), 8 (6%) patients received cardiopulmonary resuscitation, 19 (14%) patients had bilateral unreactive pupils, the median motor GCS score was 1 (IQR 1-4), and 82 (60%) patients had fever. Grade 3 DAI was present in 46 (34%) patients, and restricted diffusion was noted in the corpus callosum in 75 (55%) patients, deep gray matter in 29 (21%) patients, subcortical white matter in 23 (17%) patients, and the brainstem in 20 (15%) patients. After controlling for clinical variables, an increased number of regions with restricted diffusion, but not hemorrhagic DAI grade, was independently associated with longer time to follow commands (hazard ratio 0.68, 95% confidence interval 0.53-0.89) and worse WeeFIM scores (estimate β - 4.67, 95% confidence interval - 8.33 to - 1.01).

CONCLUSIONS

Regional restricted diffusion on early MRI is independently associated with short-term outcomes in children with severe TBI. Multicenter cohort studies are needed to validate these findings and elucidate the association of early MRI features with long-term outcomes in children with severe TBI.

Effect of erythropoietin on SOFA score, Glasgow Coma Scale and mortality in traumatic brain injury patients: a randomized-double-blind controlled trial

Background

Recent studies suggest that erythropoietin has an anti-inflammatory effect on the central nervous system. The authors aimed to investigate the effect of erythropoietin on Glasgow Coma Scale (GCS), Sequential Organ Failure Assessment (SOFA) scores, and the mortality rate of traumatic brain injury (TBI) patients.

Methods

Sixty-eight patients with available inclusion criteria were randomly allocated to the control or intervention groups. In the intervention group, erythropoietin (4000 units) was administrated on days 1, 3, and 5. In the control group, normal saline on the same days was used. The primary outcomes were the GCS and SOFA score changes during the intervention. The secondary outcomes were the ventilation period during the first 2 weeks and the 3-month mortality rate.

Results

Erythropoietin administration significantly affected SOFA score over time (P=0.008), but no significant effect on the GCS, and duration of ventilation between the two groups was observed. Finally, erythropoietin had no significant effect on the three-month mortality (23.5% vs. 38.2% in the erythropoietin and control group, respectively). However, the mortality rate in the intervention group was lower than in the control group.

Conclusion

Our finding showed that erythropoietin administration in TBI may improve SOFA score. Therefore, erythropoietin may have beneficial effects on early morbidity and clinical improvement in TBI patients.

Discovery of 2-deoxy glucose surfaced mixed layer dendrimer: a smart neuron targeted systemic drug delivery system for brain diseases

The availability of non-invasive drug delivery systems capable of efficiently transporting bioactive molecules across the blood-brain barrier to specific cells at the injury site in the brain is currently limited. Delivering drugs to neurons presents an even more formidable challenge due to their lower numbers and less phagocytic nature compared to other brain cells. Additionally, the diverse types of neurons, each performing specific functions, necessitate precise targeting of those implicated in the disease. Moreover, the complex synthetic design of drug delivery systems often hinders their clinical translation. The production of nanomaterials at an industrial scale with high reproducibility and purity is particularly challenging. However, overcoming this challenge is possible by designing nanomaterials through a straightforward, facile, and easily reproducible synthetic process. Methods: In this study, we have developed a third-generation 2-deoxy-glucose functionalized mixed layer dendrimer (2DG-D) utilizing biocompatible and cost-effective materials via a highly facile convergent approach, employing copper-catalyzed click chemistry. We further evaluated the systemic neuronal targeting and biodistribution of 2DG-D, and brain delivery of a neuroprotective agent pioglitazone (Pio) in a pediatric traumatic brain injury (TBI) model. Results: The 2DG-D exhibits favorable characteristics including high water solubility, biocompatibility, biological stability, nanoscale size, and a substantial number of end groups suitable for drug conjugation. Upon systemic administration in a pediatric mouse model of traumatic brain injury (TBI), the 2DG-D localizes in neurons at the injured brain site, clears rapidly from off-target locations, effectively delivers Pio, ameliorates neuroinflammation, and improves behavioral outcomes. Conclusions: The promising in vivo results coupled with a convenient synthetic approach for the construction of 2DG-D makes it a potential nanoplatform for addressing brain diseases.

Dysregulated brain-gut axis in the setting of traumatic brain injury: review of mechanisms and anti-inflammatory pharmacotherapies

Traumatic brain injury (TBI) is a chronic and debilitating disease, associated with a high risk of psychiatric and neurodegenerative diseases. Despite significant advancements in improving outcomes, the lack of effective treatments underscore the urgent need for innovative therapeutic strategies. The brain-gut axis has emerged as a crucial bidirectional pathway connecting the brain and the gastrointestinal (GI) system through an intricate network of neuronal, hormonal, and immunological pathways. Four main pathways are primarily implicated in this crosstalk, including the systemic immune system, autonomic and enteric nervous systems, neuroendocrine system, and microbiome. TBI induces profound changes in the gut, initiating an unrestrained vicious cycle that exacerbates brain injury through the brain-gut axis. Alterations in the gut include mucosal damage associated with the malabsorption of nutrients/electrolytes, disintegration of the intestinal barrier, increased infiltration of systemic immune cells, dysmotility, dysbiosis, enteroendocrine cell (EEC) dysfunction and disruption in the enteric nervous system (ENS) and autonomic nervous system (ANS). Collectively, these changes further contribute to brain neuroinflammation and neurodegeneration via the gut-brain axis. In this review article, we elucidate the roles of various anti-inflammatory pharmacotherapies capable of attenuating the dysregulated inflammatory response along the brain-gut axis in TBI. These agents include hormones such as serotonin, ghrelin, and progesterone, ANS regulators such as beta-blockers, lipid-lowering drugs like statins, and intestinal flora modulators such as probiotics and antibiotics. They attenuate neuroinflammation by targeting distinct inflammatory pathways in both the brain and the gut post-TBI. These therapeutic agents exhibit promising potential in mitigating inflammation along the brain-gut axis and enhancing neurocognitive outcomes for TBI patients.

Appropriate incorporation of susceptibility-weighted magnetic resonance imaging into routine imaging protocols for accurate diagnosis of traumatic brain injuries: a systematic review

Traumatic brain injury (TBI) results from physical or traumatic injuries to the brain's surrounding bony structures and associated tissues, which can lead to various sequelae, including simple concussion, acute epidural hematoma, parenchymal contusions, subarachnoid hemorrhage, diffuse axonal injury, and chronic traumatic encephalopathy. Susceptibility-weighted imaging (SWI) has enhanced the accuracy of neuroimaging for these injuries. SWI is based on 3D gradient echo magnetic resonance imaging (MRI) with long echo times and flow compensation. Owing to its sensitivity to deoxyhemoglobin, hemosiderin, iron, and calcium, SWI is extremely informative and superior to conventional MRI for the diagnosis and follow-up of patients with acute, subacute, and prolonged hemorrhage. This systematic review aimed to evaluate and summarize the published articles that report SWI results for the evaluation of TBI and to determine correlations between clinical status and SWI results. Consequently, our analysis also aimed to identify the appropriate MRI sequences to use in the assessment of patients with TBI. We searched the Medline and Embase online electronic databases for relevant papers published from 2012 onwards. We found that SWI had higher sensitivity than gradient echo MRI in detecting and characterizing microbleeds in TBIs and was able to differentiate diamagnetic calcifications from paramagnetic microhemorrhages. However, it is important that future research not only continues to evaluate the utility of SWI in TBIs but also attempts to overcome the limitations of the studies described in this review, which should help validate the conclusions and recommendations from our analysis.

PRECISION-TBI: a study protocol for a vanguard prospective cohort study to enhance understanding and management of moderate to severe traumatic brain injury in Australia

INTRODUCTION

Traumatic brain injury (TBI) is a heterogeneous condition in terms of pathophysiology and clinical course. Outcomes from moderate to severe TBI (msTBI) remain poor despite concerted research efforts. The heterogeneity of clinical management represents a barrier to progress in this area. PRECISION-TBI is a prospective, observational, cohort study that will establish a clinical research network across major neurotrauma centres in Australia. This network will enable the ongoing collection of injury and clinical management data from patients with msTBI, to quantify variations in processes of care between sites. It will also pilot high-frequency data collection and analysis techniques, novel clinical interventions, and comparative effectiveness methodology.

METHODS AND ANALYSIS

PRECISION-TBI will initially enrol 300 patients with msTBI with Glasgow Coma Scale (GCS) <13 requiring intensive care unit (ICU) admission for invasive neuromonitoring from 10 Australian neurotrauma centres. Demographic data and process of care data (eg, prehospital, emergency and surgical intervention variables) will be collected. Clinical data will include prehospital and emergency department vital signs, and ICU physiological variables in the form of high frequency neuromonitoring data. ICU treatment data will also be collected for specific aspects of msTBI care. Six-month extended Glasgow Outcome Scores (GOSE) will be collected as the key outcome. Statistical analysis will focus on measures of between and within-site variation. Reports documenting performance on selected key quality indicators will be provided to participating sites.

ETHICS AND DISSEMINATION

Ethics approval has been obtained from The Alfred Human Research Ethics Committee (Alfred Health, Melbourne, Australia). All eligible participants will be included in the study under a waiver of consent (hospital data collection) and opt-out (6 months follow-up). Brochures explaining the rationale of the study will be provided to all participants and/or an appropriate medical treatment decision-maker, who can act on the patient's behalf if they lack capacity. Study findings will be disseminated by peer-review publications.

TRIAL REGISTRATION NUMBER

NCT05855252.

Vepoloxamer improves functional recovery in rat after traumatic brain injury: A dose-response and therapeutic window study

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. There are no effective therapies available for TBI patients. Vepoloxamer is an amphiphilic polyethylene-polypropylene-polyethylene tri-block copolymer that seals membranes and restores plasma membrane integrity in damaged cells. We previously demonstrated that treatment of TBI rats with Vepoloxamer improves functional recovery. However, additional studies are needed to potentially translate Vepoloxamer treatment from preclinical studies into clinical applications. We thus conducted a study to investigate dose-response and therapeutic window of Vepoloxamer on functional recovery of adult rats after TBI. To identify the most effective dose of Vepoloxamer, male Wistar adult rats with controlled cortical impact (CCI) injury were randomly treated with 0 (vehicle), 100, 300, or 600 mg/kg of Vepoloxamer, administered intravenously (IV) at 2 h after TBI. We then performed a therapeutic window study in which the rats were treated IV with the most effective single dose of Vepoloxamer at different time points of 2 h, 4 h, 1 day, or 3 days after TBI. A battery of cognitive and neurological tests was performed. Animals were killed 35 days after TBI for histopathological analysis. Dose-response experiments showed that Vepoloxamer at all three tested doses (100, 300, 600 mg/kg) administered 2 h post injury significantly improved cognitive functional recovery, whereas Vepoloxamer at doses of 300 and 600 mg/kg, but not the 100 mg/kg dose, significantly reduced lesion volume compared to saline treatment. However, Vepoloxamer at 300 mg/kg showed significantly improved neurological and cognitive outcomes than treatment with a dose of 600 mg/kg. In addition, our data demonstrated that the dose of 300 mg/kg of Vepoloxamer administered at 2 h, 4 h, 1 day, or 3 days post injury significantly improved neurological function compared with vehicle, whereas Vepoloxamer administered at 2 h or 4 h post injury significantly improved cognitive function compared with the 1-day and 3-day treatments, with the most robust effect administered at 2 h post injury. The present study demonstrated that Vepoloxamer improves functional recovery in a dose-and time-dependent manner, with therapeutic efficacy compared with vehicle evident even when the treatment is initiated 3 days post TBI in the rat.

Traumatic Brain Injury in the Long-COVID Era

Major determinants of the biological background or reserve, such as age, biological sex, comorbidities (diabetes, hypertension, obesity, etc.), and medications (e.g., anticoagulants), are known to affect outcome after traumatic brain injury (TBI). With the unparalleled data richness of coronavirus disease 2019 (COVID-19; ∼375,000 and counting!) as well as the chronic form, long-COVID, also called post-acute sequelae SARS-CoV-2 infection (PASC), publications (∼30,000 and counting) covering virtually every aspect of the diseases, pathomechanisms, biomarkers, disease phases, symptomatology, etc., have provided a unique opportunity to better understand and appreciate the holistic nature of diseases, interconnectivity between organ systems, and importance of biological background in modifying disease trajectories and affecting outcomes. Such a holistic approach is badly needed to better understand TBI-induced conditions in their totality. Here, I briefly review what is known about long-COVID/PASC, its underlying-suspected-pathologies, the pathobiological changes induced by TBI, in other words, the TBI endophenotypes, discuss the intersection of long-COVID/PASC and TBI-induced pathobiologies, and how by considering some of the known factors affecting the person's biological background and the inclusion of mechanistic molecular biomarkers can help to improve the clinical management of TBI patients.

Targeting pyroptosis with nanoparticles to alleviate neuroinflammatory for preventing secondary damage following traumatic brain injury

Posttraumatic neuroinflammation is a key driver of secondary injury after traumatic brain injury (TBI). Pyroptosis, a proinflammatory form of programmed cell death, considerably activates strong neuroinflammation and amplifies the inflammatory response by releasing inflammatory contents. Therefore, treatments targeting pyroptosis may have beneficial effects on the treatment of secondary brain damage after TBI. Here, a cysteine-alanine-glutamine-lysine peptide-modified β-lactoglobulin (β-LG) nanoparticle was constructed to deliver disulfiram (DSF), C-β-LG/DSF, to inhibit pyroptosis and decrease neuroinflammation, thereby preventing TBI-induced secondary injury. In the post-TBI mice model, C-β-LG/DSF selectively targets the injured brain, increases DSF accumulation, and extends the time of the systemic circulation of DSF. C-β-LG/DSF can alleviate brain edema and inflammatory response, inhibit secondary brain injury, promote learning, and improve memory recovery in mice after trauma. Therefore, this study likely provided a potential approach for reducing the secondary spread of TBI.

Delayed tranexamic acid after traumatic brain injury impedes learning and memory: Early tranexamic acid is favorable but not in sham animals

BACKGROUND

Early but not late tranexamic acid (TXA) after TBI preserves blood-brain-barrier integrity, but it is unclear if and how dose timing affects cognitive recovery beyond hours postinjury. We hypothesized that early (1 hour post-TBI) but not late (24 hours post-TBI) TXA administration improves cognitive recovery for 14 days.

METHODS

CD1 male mice (n = 25) were randomized to severe TBI (injury [I], by controlled cortical impact) or sham craniotomy (S) followed by intravenous saline at 1 hour (placebo [P1]) or 30 mg/kg TXA at 1 hour (TXA1) or 24 hours (TXA24). Daily body weights, Garcia Neurological Test scores, brain/lung water content, and Morris water maze exercises quantifying swimming traffic in the platform quadrant (zone [Z] 1) and platform area (Z5) were recorded for up to 14 days.

RESULTS

Among injured groups, I-TXA1 demonstrated fastest weight gain for 14 days and only I-TXA1 showed rapid (day 1) normalization of Garcia Neurological Test ( p = 0.01 vs. I-P1, I-TXA24). In cumulative spatial trials, compared with I-TXA1, I-TXA24 hindered learning (distance to Z5 and % time in Z1, p < 0.05). Compared with I-TXA1, I-TXA24 showed poorer memory with less Z5 time (0.51 vs. 0.16 seconds, p < 0.01) and Z5 crossing frequency. Unexpectedly, TXA in uninjured animals (S-TXA1) displayed faster weight gain but inferior learning and memory.

CONCLUSION

Early TXA appears beneficial for cognitive and behavioral outcomes following TBI, although administration 24 hours postinjury consistently impairs cognitive recovery. Tranexamic acid in sham animals may lead to adverse effects on cognition.

Antioxidant theranostic copolymer-mediated reduction in oxidative stress following traumatic brain injury improves outcome in a mouse model

Following a traumatic brain injury (TBI), excess reactive oxygen species (ROS) and lipid peroxidation products (LPOx) are generated and lead to secondary injury beyond the primary insult. A major limitation of current treatments is poor target engagement, which has prevented success in clinical trials. Thus, nanoparticle-based treatments have received recent attention because of their ability to increase accumulation and retention in damaged brain. Theranostic neuroprotective copolymers (NPC3) containing thiol functional groups can neutralize ROS and LPOx. Immediate administration of NPC3 following injury in a controlled cortical impact (CCI) mouse model provides a therapeutic window in reducing ROS levels at 2.08-20.83 mg/kg in males and 5.52-27.62 mg/kg in females. This NPC3-mediated reduction in oxidative stress improves spatial learning and memory in males, while females show minimal improvement. Notably, NPC3-mediated reduction in oxidative stress prevents the bilateral spread of necrosis in male mice, which was not observed in female mice and likely accounts for the sex-based spatial learning and memory differences. Overall, these findings suggest sex-based differences to oxidative stress scavenger nanoparticle treatments, and a possible upper threshold of antioxidant activity that provides therapeutic benefit in injured brain since female mice benefit from NPC3 treatment to a lesser extent than male mice.

Intranasal human-recombinant NGF administration improves outcome in children with post-traumatic unresponsive wakefulness syndrome

BACKGROUND

Severe traumatic brain injury (TBI) is one of the most dramatic events in pediatric age and, despite advanced neuro-intensive care, the survival rate of these patients remains low. Children suffering from severe TBI show long-term sequelae, more pronounced in behavioral, neurological and neuropsychological functions leading to, in the most severe cases, an unresponsive wakefulness syndrome (UWS). Currently, no effective treatments can restore neuronal loss or produce significant improvement in these patients. In experimental animal models, human- recombinant Nerve Growth Factor (hr-NGF) promotes neural recovery supporting neuronal growth, differentiation and survival of brain cells and up-regulating the neurogenesis-associated processes. Only a few studies reported the efficacy of intranasal hr-NGF administration in children with post- traumatic UWS.

METHODS

Children with the diagnosis of post-traumatic UWS were enrolled. These patients underwent a treatment with intranasal hr-NGF administration, at a total dose of 50 gamma/kg, three times a day for 7 consecutive days. The treatment schedule was performed for 4 cycles, at one month distance each. Neuroradiogical evaluation by Positron Emission Tomography scan (PET), Single Photon Emission Computed Tomography (SPECT), Electroencephalography (EEG), and Power Spectral Density (PSD) was determined before the treatment and one month after the end. Neurological assessment was also deepened by using modified Ashworth Scale, Gross Motor Function Measure, and Disability Rating Scale.

RESULTS

Three children with post-traumatic UWS were treated. hr-NGF administration improved functional (PET and SPECT) and electrophysiological (EEG and PSD) assessment. Also clinical conditions improved, mainly for the reduction of spasticity and with the acquisition of voluntary movements, facial mimicry, attention and verbal comprehension, ability to cry, cough reflex, oral motility, and feeding capacity, with a significant improvement of their neurological scores. No side effects were reported.

CONCLUSION

These promising results and the ease of administration of this treatment make it worthwhile to be investigated further, mainly in the early stages from severe TBI and in patients with better baseline neurological conditions, to explore more thoroughly the benefits of this new approach on neuronal function recovery after traumatic brain damage.

Treating Traumatic Brain Injury with Minocycline

Traumatic brain injury (TBI) results in both rapid and delayed brain damage. The speed, complexity, and persistence of TBI present large obstacles to drug development. Preclinical studies from multiple laboratories have tested the FDA-approved anti-microbial drug minocycline (MINO) to treat traumatic brain injury. At concentrations greater than needed for anti-microbial action, MINO readily inhibits microglial activation. MINO has additional pleotropic effects including anti-inflammatory, anti-oxidant, and anti-apoptotic activities. MINO inhibits multiple proteins that promote brain injury including metalloproteases, caspases, calpain, and polyADP-ribose-polymerase-1. At these elevated doses, MINO is well tolerated and enters the brain even when the blood-brain barrier is intact. Most preclinical studies with a first dose of MINO at less than 1 h after injury have shown improved multiple outcomes after TBI. Fewer studies with more delayed dosing have yielded similar results. A small number of clinical trials for TBI have established the safety of MINO and suggested some drug efficacy. Studies are also ongoing that either improve MINO pharmacology or combine MINO with other drugs to increase its therapeutic efficacy against TBI. This review builds upon a previous, recent review by some of the authors (Lawless and Bergold, Neural Regen Res 17:2589-92, 2022). The present review includes the additional preclinical studies examining the efficacy of minocycline in preclinical TBI models. This review also includes recommendations for a clinical trial to test MINO to treat TBI.

A Potential Role Exists for Nutritional Interventions in the Chronic Phase of Mild Traumatic Brain Injury, Concussion and Sports-Related Concussion: A Systematic Review

Mild traumatic brain injury (mTBI) represents a significant burden for individuals, economies, and healthcare systems worldwide. Recovery protocols focus on medication and physiotherapy-based interventions. Animal studies have shown that antioxidants, branched-chain amino acids and omega-3 fatty acids may improve neurophysiological outcomes after TBI. However, there appears to be a paucity of nutritional interventions in humans with chronic (≥1 month) symptomology post-mTBI. This systematic literature review aimed to consolidate evidence for nutrition and dietary-related interventions in humans with chronic mTBI. The review was registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD42021277780) and conducted following the Preferred Reporting for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Three reviewers searched five databases (PubMed/MEDLINE, Web of Science, SPORTDiscus, CINAHL Complete and Cochrane), which yielded 6164 studies. Nine studies met the inclusion criteria. The main finding was the lack of interventions conducted to date, and a quality assessment of the included studies was found to be fair to good. Due to heterogeneity, a meta-analysis was not feasible. The six nutrition areas identified (omega-3 fatty acids, melatonin, Enzogenol®, MLC901, ketogenic diet and phytocannabinoids) were safe and well-tolerated. It was found that these nutritional interventions may improve cognitive failures, sleep disturbances, anxiety, physical disability, systolic blood pressure volume and sport concussion assessment tool scores following mTBI. Potential areas of improvement identified for future studies included blinding, reporting compliance, and controlling for confounders. In conclusion, further research of higher quality is needed to investigate the role of nutrition in recovery from mTBI to reduce the burden of chronic outcomes following mTBI.

Nature vs. Manmade: Comparing Exosomes and Liposomes for Traumatic Brain Injury

Traumatic brain injury (TBI) of all severities is a significant public health burden, causing a range of effects that can lead to death or a diminished quality of life. Liposomes and mesenchymal stem cell-derived exosomes are two drug delivery agents with potential to be leveraged in the treatment of TBI by increasing the efficacy of drug therapies as well as having additional therapeutic effects. They exhibit several physical similarities, but key differences affect their performances as nanocarriers. Liposomes can be produced commercially at scale, and liposomes achieve higher encapsulation efficiency. Meanwhile, the intrinsic cargo and targeting moieties of exosomes, which liposomes lack, give exosomes a greater ability to facilitate neural regeneration, and exosomes do not trigger the infusion reactions that liposomes can. However, there are concerns about both exosomes and liposomes regarding interactions with tumors. The same routes of administration can be used for both exosomes and liposomes, resulting in somewhat different distribution throughout the body. While the effect of the nanocarrier type on accumulation in the brain is not concrete, targeting leads to increased accumulation of both exosomes and liposomes in the brain, upon which on-demand release can be used for both drug deliverers. Although neither have been applied to TBI in humans, preclinical trials have shown their immense potential, as have clinical trials pertaining to other brain injuries and conditions. While questions remain, research thus far shows that the various differences make exosomes a better choice of nanocarrier for TBI.

Analysis of PEG-lipid anchor length on lipid nanoparticle pharmacokinetics and activity in a mouse model of traumatic brain injury

Traumatic brain injury (TBI) affects millions of people worldwide, yet there are currently no therapeutics that address the long-term impairments that develop in a large portion of survivors. Lipid nanoparticles (LNPs) are a promising therapeutic strategy that may address the molecular basis of TBI pathophysiology. LNPs are the only non-viral gene delivery platform to achieve clinical success, but systemically administered formulations have only been established for targets in the liver. In this work, we evaluated the pharmacokinetics and activity of LNPs formulated with polyethylene glycol (PEG)-lipids of different anchor lengths when systemically administered to a mouse model of TBI. We observed an increase in LNP accumulation and activity in the injured brain hemisphere compared to the uninjured contralateral brain hemisphere. Interestingly, transgene expression mediated by LNPs was more durable in injured brain tissue compared to off-target organs when compared between 4 and 24 hours. The PEG-lipid is an important component of LNP formulation necessary for the stable formation and storage of LNPs, but the PEG-lipid structure and content also has an impact on LNP function. LNP formulations containing various ratios of PEG-lipid with C18 (DSPE-PEG) and C14 (DMG-PEG) anchors displayed similar physicochemical properties, independent of the PEG-lipid compositions. As the proportion of DSPE-PEG was increased in formulations, blood circulation times of LNPs increased and the duration of expression increased. We also evaluated diffusion of LNPs after convection enhanced delivery (CED) in healthy brains and found LNPs distributed >1 mm away from the injection site. Understanding LNP pharmacokinetics and activity in TBI models and the impact of PEG-lipid anchor length informs the design of LNP-based therapies for TBI after systemic administration.

Clinical factors associated with delayed emergency department visit in intracranial traumatic brain injury: from a multicenter injury surveillance registry

INTRODUCTION

Early diagnosis and intervention by visiting the emergency department (ED) are important for traumatic brain injury (TBI). We evaluate the factors associated with delayed ED visits in patients with intracranial TBI.

METHODS

A retrospective multicenter observational study using the ED-based injury in-depth surveillance database (EDIIS) was designed. Patients with intracranial TBI with an alert mentality at ED presentation from 2014 to 2019 were enrolled. Patients were categorized into four groups according to ED visit time after injury (<1 h, 1-3 h, 3-12 h, and >12 h). ED visits after 12 h were defined as delayed ED visits. The factors associated with delayed ED visits were identified using multivariable logistic regression analysis.

RESULTS

Among 15,620 patients with TBI enrolled in the final analysis, 2,190 (14.0%) visited the ED 12 h after injury. Multivariable analysis identified the following factors as independent predictors for delayed ED visit such as unintentionally struck by or against an object or unintentional fall as a trauma mechanism, injury during ordinary activities, indoor injury, injury during nighttime, winter season, combined subdural hemorrhage and epidural hemorrhage.

CONCLUSION

In patients with intracranial TBI with an alert mentality, multiple factors related to patient demographics and injury characteristics were associated with the time interval from injury to ED visit.

Sex-based differences of antioxidant enzyme nanoparticle effects following traumatic brain injury

Following traumatic brain injury (TBI), reactive oxygen species (ROS) are released in excess, causing oxidative stress, carbonyl stress, and cell death, which induce the additional release of ROS. The limited accumulation and retention of small molecule antioxidants commonly used in clinical trials likely limit the target engagement and therapeutic effect in reducing secondary injury. Small molecule drugs also need to be administered every several hours to maintain bioavailability in the brain. Therefore, there is a need for a burst and sustained release system with high accumulation and retention in the injured brain. Here, we utilized Pro-NP™ with a size of 200 nm, which was designed to have a burst and sustained release of encapsulated antioxidants, Cu/Zn superoxide dismutase (SOD1) and catalase (CAT), to scavenge ROS for >24 h post-injection. Here, we utilized a controlled cortical impact (CCI) mouse model of TBI and found the accumulation of Pro-NP™ in the brain lesion was highest when injected immediately after injury, with a reduction in the accumulation with delayed administration of 1 h or more post-injury. Pro-NP™ treatment with 9000 U/kg SOD1 and 9800 U/kg CAT gave the highest reduction in ROS in both male and female mice. We found that Pro-NP™ treatment was effective in reducing carbonyl stress and necrosis at 1 d post-injury in the contralateral hemisphere in male mice, which showed a similar trend to untreated female mice. Although we found that male and female mice similarly benefit from Pro-NP™ treatment in reducing ROS levels 4 h post-injury, Pro-NP™ treatment did not significantly affect markers of post-traumatic oxidative stress in female CCI mice as compared to male CCI mice. These findings of protection by Pro-NP™ in male mice did not extend to 7 d post-injury, which suggests subsequent treatments with Pro-NP™ may be needed to afford protection into the chronic phase of injury. Overall, these different treatment effects of Pro-NP™ between male and female mice suggest important sex-based differences in response to antioxidant nanoparticle delivery and that there may exist a maximal benefit from local antioxidant activity in injured brain.

Emerging Materials, Wearables, and Diagnostic Advancements in Therapeutic Treatment of Brain Diseases

Among the most critical health issues, brain illnesses, such as neurodegenerative conditions and tumors, lower quality of life and have a significant economic impact. Implantable technology and nano-drug carriers have enormous promise for cerebral brain activity sensing and regulated therapeutic application in the treatment and detection of brain illnesses. Flexible materials are chosen for implantable devices because they help reduce biomechanical mismatch between the implanted device and brain tissue. Additionally, implanted biodegradable devices might lessen any autoimmune negative effects. The onerous subsequent operation for removing the implanted device is further lessened with biodegradability. This review expands on current developments in diagnostic technologies such as magnetic resonance imaging, computed tomography, mass spectroscopy, infrared spectroscopy, angiography, and electroencephalogram while providing an overview of prevalent brain diseases. As far as we are aware, there hasn't been a single review article that addresses all the prevalent brain illnesses. The reviewer also looks into the prospects for the future and offers suggestions for the direction of future developments in the treatment of brain diseases.

NIR-II Dyad-Doped Ratiometric Nanosensor with Enhanced Spectral Fidelity in Biological Media for In Vivo Biosensing

Ratiometric fluorescence nanosensors provide quantitative biological information. However, spectral shift and distortion of ratiometric nanosensors in biological media often compromise sensing accuracy, limiting in vivo applications. Here, we develop a fluorescent dyad (aBOP-IR1110) in the second near-infrared (NIR-II) window by covalently linking an asymmetric aza-BODIPY with a ONOO^--responsive meso-thiocyanine. The dyad encapsulated in the PEGylated nanomicelle largely improves spectral fidelity in serum culture by >9.4 times compared to that of its noncovalent counterpart. The increased molecular weights (>1480 Da) and hydrophobicity (LogP of 7.87-12.36) lock dyads inside the micelles, which act as the shield against the external environment. ONOO^--altered intramolecular Förster resonance energy transfer (FRET) generates linear ratiometric response with better serum tolerance, enabling us to monitor the dynamics of oxidative stress in traumatic brain injury and evaluate therapeutic efficiency. The results show high correlation with in vitro triphenyltetrazolium chloride staining, suggesting the potential of NIR-II dyad-doped nanosensor for in vivo high-fidelity sensing applications.

Elevated C-reactive protein-to-albumin ratio with fever is a predictor of poor functional outcome in patients with mild traumatic brain injury

Introduction

The C-reactive protein -to-albumin ratio (CAR), a novel inflammation-based prognostic score, is useful in predicting clinical outcomes, including those in central nervous system diseases. However, no report has identified the relationship between CAR and long-term clinical outcomes in patients with mild traumatic brain injury (mTBI). We aimed to evaluate the relationship between CAR and long-term functional outcomes in patients with mTBI and analyze whether CAR is associated with the presence of fever.

Methods

This was a retrospective observational study includes 387 adult patients with mTBI who were treated at a level-1 trauma center between 2017 and 2021. The main exposure variable was an elevated CAR, and the main outcomes were degrees of disability and quality of life measured using the modified Rankin Scale (mRS). A multivariable logistic regression analysis was performed to estimate the effect size of CAR on study outcomes. An interaction analysis was performed between CAR and fever on study outcomes.

Results

Elevated CAR had no significant association with poor functional outcomes (aOR [95% CI]: 1.35 [0.39-4.69]) in patients with mTBI. In the interaction analysis, elevated CAR was not associated with increased poor functional outcomes in the absence of fever (1.08 [0.55-2.13]), but a significant increase in poor functional outcomes was observed when elevated CAR was accompanied by fever (1.32 [1.14-2.56)).

Conclusions

Elevated CAR with fever increased the risk of poor functional recovery at 6 months after hospital discharge in patients with mTBI. Our study findings suggest the need for strategies for the prevention of long-term poor functional recovery in the presence of high CAR and fever in patients with mTBI.

Group III metabotropic glutamate receptors as promising targets for neuroprotective therapy: Particular emphasis on the role of mGlu4 and mGlu7 receptors

There is still no effective treatment for central nervous system (CNS) pathologies, including cerebral ischemia, neurotrauma, and neurodegenerative diseases in which the Glu/GABA balance is disturbed with associated excitotoxicity. It is thus important to search for new efficacious therapeutic strategies. Preclinical studies on the role of metabotropic glutamate receptors (mGluRs) in neuroprotection conducted over the years show that these receptors may have therapeutic potential in these CNS disorders. However, clinical trials, especially for treating Parkinson's disease, have been unsatisfactory. This review focuses on the specific role of group III mGluRs in neuroprotection in experimental in vitro and in vivo models of excitotoxicity/neurotoxicity using neurotoxins as well as ischemia, traumatic brain injury, and neurodegenerative diseases such as Parkinson's disease, Alzheimer's diseases, and multiple sclerosis. The review highlights recent preclinical studies in which group III mGluR ligands (especially those acting at mGluR4 or mGluR7) were administered after damage, thus emphasizing the importance of the therapeutic time window in the treatment of ischemic stroke and traumatic brain injury. From a clinical standpoint, the review also highlights studies using group III mGluR agonists with favorable neuroprotective efficacy (histological and functional) in experimental ischemic stroke, including healthy normotensive and-hypertensive rats. This review also summarizes possible mechanisms underlying the neuroprotective activity of the group III mGluR ligands, which may be helpful in developing more effective and safe therapeutic strategies. Therefore, to fully assess the role of these receptors in neuroprotection, it is necessary to uncover new selective ligands, primarily those stimulating mGlu4 and mGlu7 receptors.

N-methyl-D-aspartate receptor antagonists in improving cognitive deficits following traumatic brain injury: a systematic review

OBJECTIVE

To review the role of N-methyl-D-aspartate receptor (NMDAR) antagonists in managing post-TBI cognitive deficits.

METHODS

A search of PubMed, Embase, and Cochrane was conducted on Jan 12, 2021 without publication date or language restriction.

RESULTS

Forty-seven studies were included, involving 20 (42.6%) randomized controlled trials. Four (8.5%) studies had a low risk of bias (RoB), while 34 (72.3%) had unclear and nine (19.2%) had high RoB. Six NMDAR antagonists had been investigated: amantadine (n = 32), memantine (n = 4), magnesium (n = 4), traxoprodil (n = 3), selfotel (n = 2), and dextromethorphan (n = 2).

CONCLUSION

Although some benefits were observed, there are still some concerns regarding the efficacy and safety of NMDAR antagonists in improving post-TBI cognitive deficits. Further research is required to examine whether (i) these agents, notably amantadine, could accelerate cognitive improvement and shorten the hospital stay, (ii) these agents affect different cognitive domains/subdomains in the same direction, (iii) an optimal therapeutic time window exists, (iv) a member of this drug class can be proved to be effective without interfering in non-excitotoxic actions of glutamate, (v) they can be more effective as part of combination therapies or in particular subgroups of patients with TBI.

Utility of neuromuscular blockade reversal in the evaluation of acute neurosurgical patients: A retrospective case-series

OBJECTIVE

Sugammadex reversal of neuromuscular blocking agents (NMBAs) is usually performed postoperatively. A scarcity of literature exists exploring sugammadex use for timely neurological examination of neurosurgical patients. NMBAs, like rocuronium, are used in the Emergency Department during intubation and their unpredictable duration of action often impedes timely and accurate assessment of patient neurological status. We aim to explore the role of sugammadex in evaluating patients in need of acute neurosurgical care.

METHODS

Retrospective assessment of patients presenting with traumatic brain injury or intracranial hemorrhage was conducted at our level 1 trauma center. Patients of interest were those for whom sugammadex reversal of rocuronium neuromuscular blockade, from intubating doses, was pursued to ensure timely neurologic assessment. Nine patients were identified for whom GCS pre-/post-sugammadex, rocuronium dosing, elapsed time between rocuronium administration and reversal, and clinical course data were retrieved.

RESULTS

Arrival GCS was 5.2 ± 3.2, with intubation accomplished within 10 ± 2.5 min of presentation. Rocuronium dosing was consistent between patients, average single dose of 1.2 ± 0.3 mg/kg. Lingering neuromuscular blockade ranged from 28 to 132 min (87.3 ± 34.3 min). All patients exhibited a GCS of 3 T upon initial neurosurgical evaluation, prior to reversal. Post-reversal GCS rose to 6.0 T ± 2.2. Sugammadex facilitated more accurate clinical decision making in 8 of 9 patients, including prevention of unnecessary invasive procedures. Two of 9 patients were eventually discharged home or to a rehabilitation facility.

CONCLUSIONS

Rocuronium neuromuscular blockade can linger beyond pharmacokinetic predictions, thus delaying timely and precise neurologic assessment. Our data suggests sugammadex may be a useful addition to the clinician's armamentarium for acute neurologic assessment in the neurosurgical population. Sugammadex may impact clinical decision-making in certain patients and allow for more informed decision-making by families and physicians alike. Prospective studies are needed to definitively assess the impact of sugammadex on outcomes in acute neurosurgical settings.

Neuroprotection by the noble gases argon and xenon as treatments for acquired brain injury: a preclinical systematic review and meta-analysis

BACKGROUND

The noble gases argon and xenon are potential novel neuroprotective treatments for acquired brain injuries. Xenon has already undergone early-stage clinical trials in the treatment of ischaemic brain injuries, with mixed results. Argon has yet to progress to clinical trials as a treatment for brain injury. Here, we aim to synthesise the results of preclinical studies evaluating argon and xenon as neuroprotective therapies for brain injuries.

METHODS

After a systematic review of the MEDLINE and Embase databases, we carried out a pairwise and stratified meta-analysis. Heterogeneity was examined by subgroup analysis, funnel plot asymmetry, and Egger's regression.

RESULTS

A total of 32 studies were identified, 14 for argon and 18 for xenon, involving measurements from 1384 animals, including murine, rat, and porcine models. Brain injury models included ischaemic brain injury after cardiac arrest (CA), neurological injury after cardiopulmonary bypass (CPB), traumatic brain injury (TBI), and ischaemic stroke. Both argon and xenon had significant (P<0.001), positive neuroprotective effect sizes. The overall effect size for argon (CA, TBI, stroke) was 18.1% (95% confidence interval [CI], 8.1-28.1%), and for xenon (CA, TBI, stroke) was 34.1% (95% CI, 24.7-43.6%). Including the CPB model, only present for xenon, the xenon effect size (CPB, CA, TBI, stroke) was 27.4% (95% CI, 11.5-43.3%). Xenon, both with and without the CPB model, was significantly (P<0.001) more protective than argon.

CONCLUSIONS

These findings provide evidence to support the use of xenon and argon as neuroprotective treatments for acquired brain injuries. Current evidence suggests that xenon is more efficacious than argon overall.

Oxidative stress and mitochondrial dysfunction following traumatic brain injury: From mechanistic view to targeted therapeutic opportunities

Traumatic brain injury (TBI) is one of the most prevalent causes of permanent physical and cognitive disabilities. TBI pathology results from primary insults and a multi-mechanistic biochemical process, termed as secondary brain injury. Currently, there are no pharmacological agents for definitive treatment of patients with TBI. This article is presented with the purpose of reviewing molecular mechanisms of TBI pathology, as well as potential strategies and agents against pathological pathways. In this review article, materials were obtained by searching PubMed, Scopus, Elsevier, Web of Science, and Google Scholar. This search was considered without time limitation. Evidence indicates that oxidative stress and mitochondrial dysfunction are two key mediators of the secondary injury cascade in TBI pathology. TBI-induced oxidative damage results in the structural and functional impairments of cellular and subcellular components, such as mitochondria. Impairments of mitochondrial electron transfer chain and mitochondrial membrane potential result in a vicious cycle of free radical formation and cell apoptosis. The results of some preclinical and clinical studies, evaluating mitochondria-targeted therapies, such as mitochondria-targeted antioxidants and compounds with pleiotropic effects after TBI, are promising. As a proposed strategy in recent years, mitochondria-targeted multipotential therapy is a new hope, waiting to be confirmed. Moreover, based on the available findings, biologics, such as stem cell-based therapy and transplantation of mitochondria are novel potential strategies for the treatment of TBI; however, more studies are needed to clearly confirm the safety and efficacy of these strategies.

Evaluation of Progesterone Receptor Antagonist and Maxi-K Channel Agonist as Neuroprotective in Feeney's Weight Drop Model of TBI

Background

Neuroprotection in traumatic brain injury (TBI) is an unmet medical need.

Objective

We evaluated two agents, aglepristone (progesterone receptor antagonist) and N-salicyloyltryptamine (STP) (activator of Maxi-K channel in GH3 cells), for neuroprotection in Feeney's weight drop model of TBI.

Material and Methods

Forty-eight male Wistar rats were divided into six groups (n = 8 per group). A battery of six neurobehavioral tests was evaluated at the end of the first week (EO1W), second week (EO2W), and third week (EO3W). In addition, histopathological and immunohistochemistry (BAX, Bcl-2, and M30 Cytodeath) tests were performed at EO3W.

Results

Aglepristone at 10 mg/kg showed significant neuroprotection compared to control as assessed by Rota-rod test at EO1W, VEFP right paw and 28-point neurobehavioral test at EO2W, MWM test at EO3W, and positive histopathological and IHC findings. Aglepristone at 20 mg/kg showed negative results as assessed by BAX expression, downregulation of Bcl-2, and positive M30 Cytodeath, thereby suggesting toxicity at higher doses. STP 100 mg/kg showed modest neuroprotective activity but failed to show a dose-response relationship at a dose of 50 mg/kg.

Conclusion

The study shows that progesterone receptor antagonists have neuroprotection at lower doses and toxicity at higher doses.

Immunomodulatory protein from ganoderma microsporum protects against oxidative damages and cognitive impairments after traumatic brain injury

A traumatic brain injury (TBI) causes abnormal proliferation of neuroglial cells, and over-release of glutamate induces oxidative stress and inflammation and leads to neuronal death, memory deficits, and even death if the condition is severe. There is currently no effective treatment for TBI. Recent interests have focused on the benefits of supplements or natural products like Ganoderma. Studies have indicated that immunomodulatory protein from Ganoderma microsporum (GMI) inhibits oxidative stress in lung cancer cells A549 and induces cancer cell death by causing intracellular autophagy. However, no evidence has shown the application of GMI on TBI. Thus, this study addressed whether GMI could be used to prevent or treat TBI through its anti-inflammation and antioxidative effects. We used glutamate-induced excitotoxicity as in vitro model and penetrating brain injury as in vivo model of TBI. We found that GMI inhibits the generation of intracellular reactive oxygen species and reduces neuronal death in cortical neurons against glutamate excitotoxicity. In neurite injury assay, GMI promotes neurite regeneration, the length of the regenerated neurite was even longer than that of the control group. The animal data show that GMI alleviates TBI-induced spatial memory deficits, expedites the restoration of the injured areas, induces the secretion of brain-derived neurotrophic factors, increases the superoxide dismutase 1 (SOD-1) and lowers the astroglial proliferation. It is the first paper to apply GMI to brain-injured diseases and confirms that GMI reduces oxidative stress caused by TBI and improves neurocognitive function. Moreover, the effects show that prevention is better than treatment. Thus, this study provides a potential treatment in naturopathy against TBI.

Theranostic Copolymers Neutralize Reactive Oxygen Species and Lipid Peroxidation Products for the Combined Treatment of Traumatic Brain Injury

Traumatic brain injury (TBI) results in the generation of reactive oxygen species (ROS) and lipid peroxidation product (LPOx), including acrolein and 4-hydroxynonenal (4HNE). The presence of these biochemical derangements results in neurodegeneration during the secondary phase of the injury. The ability to rapidly neutralize multiple species could significantly improve outcomes for TBI patients. However, the difficulty in creating therapies that target multiple biochemical derangements simultaneously has greatly limited therapeutic efficacy. Therefore, our goal was to design a material that could rapidly bind and neutralize both ROS and LPOx following TBI. To do this, a series of thiol-functionalized biocompatible copolymers based on lipoic acid methacrylate and polyethylene glycol monomethyl ether methacrylate (FW ∼ 950 Da) (O950) were prepared. A polymerizable gadolinium-DOTA methacrylate monomer (Gd-MA) was also synthesized starting from cyclen to facilitate direct magnetic resonance imaging and in vivo tracking of accumulation. These neuroprotective copolymers (NPCs) were shown to rapidly and effectively neutralize both ROS and LPOx. Horseradish peroxidase absorbance assays showed that the NPCs efficiently neutralized H₂O₂, while R-phycoerythrin protection assays demonstrated their ability to protect the fluorescent protein from oxidative damage. ¹H NMR studies indicated that the thiol-functional NPCs rapidly form covalent bonds with acrolein, efficiently removing it from solution. In vitro cell studies with SH-SY5Y-differentiated neurons showed that NPCs provide unique protection against toxic concentrations of both H₂O₂ and acrolein. NPCs rapidly accumulate and are retained in the injured brain in controlled cortical impact mice and reduce post-traumatic oxidative stress. Therefore, these materials show promise for improved target engagement of multiple biochemical derangements in hopes of improving TBI therapeutic outcomes.

Patients' and professionals' perspectives on the consideration of patients' convenient therapy periods as part of personalised rehabilitation: a focus group study with patients and therapists from inpatient neurological rehabilitation

BACKGROUND

Research on the optimal period for administering health services, especially rehabilitation interventions, is scarce. The aims of this study were to explore the construct of patients' convenient therapy periods and to identify indicators based on the perspectives of patients and different health professionals from inpatient neurological rehabilitation clinics.

METHODS

This study was part of a larger project on patients' convenient therapy periods following a mixed methods approach. In the current study a grounded theory approach was employed based on the use of focus group interviews. Focus group interviews were conducted in three different inpatient neurological rehabilitation clinics. Patients and therapists from inpatient neurological rehabilitation clinics who were able to speak and to participate in conversations were included.

RESULTS

A total of 41 persons, including 23 patients and 18 therapists, such as music and occupational therapists, participated in a total of six focus group interviews. The analysis of the focus group interviews resulted in the identification of a total of 1261 codes, which could be summarised in fifteen categories. However, these categories could be divided into five indicators and ten impact factors of convenient therapy periods. Identified indicators were verbal and non-verbal communication, mental functions, physiological needs, recreational needs, and therapy initiation.

CONCLUSIONS

The results provide initial evidence that convenient therapy periods are clinically relevant for patients and therapists. Different states of patients' ability to effectively participate in a rehabilitation intervention exist. A systematic consideration of patients' convenient therapy periods could contribute to a personalised and more efficient delivery of intervention in neurological rehabilitation. To our knowledge, this study is one of the first attempts to research convenient therapy periods.

Predictors of thoracic and lumbar spine injuries in patients with TBI: A nationwide analysis

OBJECTIVE

Cervical spine injury screening is common practice for traumatic brain injury (TBI) patients. However, risk factors for concomitant thoracolumbar trauma remain unknown. We characterized epidemiology and clinical risk for concomitant thoracolumbar trauma in TBI.

METHODS

We conducted a multi-center, retrospective cohort analysis of TBI patients in the National Trauma Data Bank from 2011-2014 using multivariable logistic regression.

RESULTS

Out of 768,718 TBIs, 46,654 (6.1%) and 42,810 (5.6%) patients were diagnosed with thoracic and lumbar spine fractures, respectively. Only 11% of thoracic and 7% of lumbar spine fracture patients had an accompanying spinal cord injury at any level. The most common mechanism of injury was motor vehicle accident (67% of thoracic and 71% and lumbar fractures). Predictors for both thoracic and lumbar fractures included moderate (thoracic: OR 1.26, 95%CI 1.21-1.31; lumbar: OR 1.13, 95%CI 1.08-1.18) and severe Glasgow Coma Scale (GCS) score (OR 1.71, 95%CI 1.67-1.75; OR 1.17, 95%CI 1.13-1.20) compared to mild; epidural hematoma (OR 1.36, 95%CI 1.28-1.44; OR 1.1, 95%CI 1.04-1.19); lower extremity injury (OR 1.38, 95%CI 1.35-1.41; OR 2.50, 95%CI 2.45-2.55); upper extremity injury (OR 2.19, 95%CI 2.14-2.23; OR 1.15, 95%CI 1.13-1.18); smoking (OR 1.09, 95%CI 1.06-1.12; OR 1.12, 95%CI 1.09-1.15); and obesity (OR 1.39, 95%CI 1.34-1.45; OR 1.29, 95%CI 1.24-1.35). Thoracic injuries (OR 4.45; 95% CI 4.35-4.55) predicted lumbar fractures, while abdominal injuries (OR 2.02; 95% CI 1.97-2.07) predicted thoracic fractures.

CONCLUSIONS

We identified GCS, smoking, upper and lower extremity injuries, and obesity as common risk factors for thoracic and lumbar spinal fractures in TBI.

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

Background

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

Methods

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

Results

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

Conclusion

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

Cellular and Molecular Targets for Non-Invasive, Non-Pharmacological Therapeutic/Rehabilitative Interventions in Acute Ischemic Stroke

BACKGROUND

Cerebral circulation delivers the blood flow to the brain through a dedicated network of sanguine vessels. A healthy human brain can regulate cerebral blood flow (CBF) according to any physiological or pathological challenges. The brain is protected by its self-regulatory mechanisms, which are dependent on neuronal and support cellular populations, including endothelial ones, as well as metabolic, and even myogenic factors.

OBJECTIVES

Accumulating data suggest that "non-pharmacological" approaches might provide new opportunities for stroke therapy, such as electro-/acupuncture, hyperbaric oxygen therapy, hypothermia/cooling, photobiomodulation, therapeutic gases, transcranial direct current stimulations, or transcranial magnetic stimulations. We reviewed the recent data on the mechanisms and clinical implications of these non-pharmaceutical treatments.

METHODS

To present the state-of-the-art for currently available non-invasive, non-pharmacological-related interventions in acute ischemic stroke, we accomplished this synthetic and systematic literature review based on the Preferred Reporting Items for Systematic Principles Reviews and Meta-Analyses (PRISMA).

RESULTS

The initial number of obtained articles was 313. After fulfilling the five steps in the filtering/selection methodology, 54 fully eligible papers were selected for synthetic review. We enhanced our documentation with other bibliographic resources connected to our subject, identified in the literature within a non-standardized search, to fill the knowledge gaps. Fifteen clinical trials were also identified.

DISCUSSION

Non-invasive, non-pharmacological therapeutic/rehabilitative interventions for acute ischemic stroke are mainly holistic therapies. Therefore, most of them are not yet routinely used in clinical practice, despite some possible beneficial effects, which have yet to be supplementarily proven in more related studies. Moreover, few of the identified clinical trials are already completed and most do not have final results.

CONCLUSIONS

This review synthesizes the current findings on acute ischemic stroke therapeutic/rehabilitative interventions, described as non-invasive and non-pharmacological.

Clinically relevant mitochondrial-targeted therapy improves chronic outcomes after traumatic brain injury

Pioglitazone, an FDA-approved compound, has been shown to target the novel mitochondrial protein mitoNEET and produce short-term neuroprotection and functional benefits following traumatic brain injury. To expand on these findings, we now investigate the dose- and time-dependent effects of pioglitazone administration on mitochondrial function after experimental traumatic brain injury. We then hypothesize that optimal pioglitazone dosing will lead to ongoing neuroprotection and cognitive benefits that are dependent on pioglitazone-mitoNEET signalling pathways. We show that delayed intervention is significantly more effective than early intervention at improving acute mitochondrial bioenergetics in the brain after traumatic brain injury. In corroboration, we demonstrate that mitoNEET is more heavily expressed, especially near the cortical contusion, in the 18 h following traumatic brain injury. To explore whether these findings relate to ongoing pathological and behavioural outcomes, mice received controlled cortical impact followed by initiation of pioglitazone treatment at either 3 or 18 h post-injury. Mice with treatment initiation at 18 h post-injury exhibited significantly improved behaviour and tissue sparing compared to mice with pioglitazone initiated at 3 h post-injury. Further using mitoNEET knockout mice, we show that this therapeutic effect is dependent on mitoNEET. Finally, we demonstrate that delayed pioglitazone treatment improves serial motor and cognitive performance in conjunction with attenuated brain atrophy after traumatic brain injury. This study illustrates that mitoNEET is the critical target for delayed pioglitazone intervention after traumatic brain injury, mitochondrial-targeting is highly time-dependent after injury and there is an extended therapeutic window to effectively treat mitochondrial dysfunction after brain injury.

Intranasal delivery of exosomes from human adipose derived stem cells at forty-eight hours post injury reduces motor and cognitive impairments following traumatic brain injury

The neuroprotective role of human adipose-derived stems cells (hASCs) has raised great interest in regenerative medicine due to their ability to modulate their surrounding environment. Our group has demonstrated that exosomes derived from hASC (hASCexo) are a cell-free regenerative approach to long term recovery following traumatic brain injury (TBI). Previously, we demonstrated the efficacy of exosome treatment with intravenous delivery at 3 h post TBI in rats. Here, we show efficacy of exosomes through intranasal delivery at 48 h post TBI in mice lengthening the therapeutic window of treatment and therefore increasing possible translation to clinical studies. Our findings demonstrate significant recovery of motor impairment assessed by an elevated body swing test in mice treated with exosomes containing MALAT1 compared to both TBI mice without exosomes and exosomes depleted of MALAT1. Significant cognitive improvement was seen in the reversal trial of 8 arm radial arm water maze in mice treated with exosomes containing MALAT1. Furthermore, cortical damage was significantly reduced in mice treated with exosomes containing MALAT1 as well as decreased MHCII+ staining of microglial cells. Mice without exosomes or treated with exosomes depleted of MALAT1 did not show similar recovery. Results demonstrate both inflammation related genes and NRTK3 (TrkC) are target genes modulated by hASC exosomes and further that MALAT1 in hASC exosomes regulates expression of full length TrkC thereby activating the MAPK pathway and promoting recovery. Exosomes are a promising therapeutic approach following TBI with a therapeutic window of at least 48 h and contain long noncoding RNA's, specifically MALAT1 that play a vital role in the mechanism of action.

The Current State of Traumatic Brain Injury Biomarker Measurement Methods

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

A Variable Height Microfluidic Device for Multiplexed Immunoassay Analysis of Traumatic Brain Injury Biomarkers

Traumatic brain injury (TBI) is a leading cause of global morbidity and mortality, partially due to the lack of sensitive diagnostic methods and efficacious therapies. Panels of protein biomarkers have been proposed as a way of diagnosing and monitoring TBI. To measure multiple TBI biomarkers simultaneously, we present a variable height microfluidic device consisting of a single channel that varies in height between the inlet and outlet and can passively multiplex bead-based immunoassays by trapping assay beads at the point where their diameter matches the channel height. We developed bead-based quantum dot-linked immunosorbent assays (QLISAs) for interleukin-6 (IL-6), glial fibrillary acidic protein (GFAP), and interleukin-8 (IL-8) using DynabeadsTM M-450, M-270, and MyOneTM, respectively. The IL-6 and GFAP QLISAs were successfully multiplexed using a variable height channel that ranged in height from ~7.6 µm at the inlet to ~2.1 µm at the outlet. The IL-6, GFAP, and IL-8 QLISAs were also multiplexed using a channel that ranged in height from ~6.3 µm at the inlet to ~0.9 µm at the outlet. Our system can keep pace with TBI biomarker discovery and validation, as additional protein biomarkers can be multiplexed simply by adding in antibody-conjugated beads of different diameters.

Preliminary Evidence for the Clinical Utility of Tactile Somatosensory Assessments of Sport-Related mTBI

OBJECTIVES

To evaluate the clinical utility of tactile somatosensory assessments to assist clinicians in diagnosing sport-related mild traumatic brain injury (SR-mTBI), classifying recovery trajectory based on performance at initial clinical assessment, and determining if neurophysiological recovery coincided with clinical recovery.

RESEARCH DESIGN

Prospective cohort study with normative controls.

METHODS

At admission (n = 79) and discharge (n = 45/79), SR-mTBI patients completed the SCAT-5 symptom scale, along with the following three components from the Cortical Metrics Brain Gauge somatosensory assessment (BG-SA): temporal order judgement (TOJ), TOJ with confounding condition (TOJc), and duration discrimination (DUR). To assist SR-mTBI diagnosis on admission, BG-SA performance was used in logistic regression to discriminate cases belonging to the SR-mTBI sample or a healthy reference sample (pooled BG-SA data for healthy participants in previous studies). Decision trees evaluated how accurately BG-SA performance classified SR-mTBI recovery trajectories.

RESULTS

BG-SA TOJ, TOJc, and DUR poorly discriminated between cases belonging to the SR-mTBI sample or a healthy reference sample (0.54-0.70 AUC, 47.46-64.71 PPV, 48.48-61.11 NPV). The BG-SA evaluated did not accurately classify SR-mTBI recovery trajectories (> 14-day resolution 48%, ≤14-day resolution 54%, lost to referral/follow-up 45%). Mann-Whitney U tests revealed differences in BG-SA TOJc performance between SR-mTBI participants and the healthy reference sample at initial clinical assessment and at clinical recovery (p < 0.05).

CONCLUSIONS

BG-SA TOJ, TOJc, and DUR appear to have limited clinical utility to assist clinicians with diagnosing SR-mTBI or predicting recovery trajectories under ecologically valid conditions. Neurophysiological abnormalities persisted beyond clinical recovery given abnormal BG-SA TOJc performance observed when SR-mTBI patients achieved clinical recovery.

Common Symptoms of Mild Traumatic Brain Injury and Work Functioning of Active-Duty Service Members with a History of Deployment

This study used data from the Military Health System Data Repository to examine the association between mild traumatic brain injuries (mTBI) and work functioning such as work duty limitations, hospital emergency room visits and inpatient admissions for active-duty service members (ADSMs). Further, this study assessed the role that common symptoms of mTBI play in work functioning. Multivariate results showed that having a mTBI diagnosis is not a major factor that results in being "released with work duty limitations". However, findings from these regression models also showed that the interaction of mTBI with cognitive and linguistic symptoms resulted in odds of 3.63 (CI: 1.40-9.36, p < 0.01) for being "released with work duty limitations" and odds of 4.98 (CI: 1.16-21.39, p < 0.05) for having any emergency department visits compared to those with no diagnosis of mTBI and none of these symptoms. Additionally, the interaction of mTBI with sleep disturbance and chronic pain showed odds of 2.72 (CI: 1.31-5.65, p < 0.01) and odds of 11.56 (CI: 2.65-50.44, p < 0.01) for being "released with work duty limitations" compared to those with no diagnosis of TBI and none of these symptoms, respectively. Further research is needed to investigate the association between mTBI and duration of time off work to provide a comprehensive understanding of the effect of mTBI on work functioning in the Military Health System.

Delayed dosing of minocycline plus N-acetylcysteine reduces neurodegeneration in distal brain regions and restores spatial memory after experimental traumatic brain injury

Multiple drugs to treat traumatic brain injury (TBI) have failed clinical trials. Most drugs lose efficacy as the time interval increases between injury and treatment onset. Insufficient therapeutic time window is a major reason underlying failure in clinical trials. Few drugs have been developed with therapeutic time windows sufficiently long enough to treat TBI because little is known about which brain functions can be targeted if therapy is delayed hours to days after injury. We identified multiple injury parameters that are improved by first initiating treatment with the drug combination minocycline (MINO) plus N-acetylcysteine (NAC) at 72 h after injury (MN72) in a mouse closed head injury (CHI) experimental TBI model. CHI produces spatial memory deficits resulting in impaired performance on Barnes maze, hippocampal neuronal loss, and bilateral damage to hippocampal neurons, dendrites, spines and synapses. MN72 treatment restores Barnes maze acquisition and retention, protects against hippocampal neuronal loss, limits damage to dendrites, spines and synapses, and accelerates recovery of microtubule associated protein 2 (MAP2) expression, a key protein in maintaining proper dendritic architecture and synapse density. These data show that in addition to the structural integrity of the dendritic arbor, spine and synapse density can be successfully targeted with drugs first dosed days after injury. Retention of substantial drug efficacy even when first dosed 72 h after injury makes MINO plus NAC a promising candidate to treat clinical TBI.

Neuroprotective response and efficacy of intravenous administration of mesenchymal stem cells in traumatic brain injury mice

Cellular transplantation of stem cells can be a beneficial treatment approach for neurodegenerative diseases such as traumatic brain injury (TBI). In this study, we investigated the proliferation and differentiation potential of infused mesenchymal stem cells (MSCs) after localisation at the injury site. We evaluated the appropriate homing of infused MSCs through immunohistochemistry, followed by Y-chromosome-specific polymerase chain reaction and fluorescent in situ hybridisation analyses. The proliferation and differentiation of infused MSCs were analysed using exogenous cell tracer 5'-bromo-2'-deoxyuridine (BrdU) labelling and neuronal specific markers, respectively. Structural and functional recovery in TBI mice were examined by performing magnetic resonance imaging and different behavioural assessments, respectively. Results demonstrated a significantly high number of BrdU-positive cells in the lesion region in the MSC-infused group compared with control and TBI groups. Infused MSCs were well differentiated into neural-like cells and expressed significantly more neural markers (neuronal nuclear antigen [NeuN], microtubule-associated protein 2 [MAP2] and glial fibrillary acid protein [GFAP]). Improved tissue abnormalities as well as functional behaviours were observed in MSC-infused TBI mice, implying the substantial proliferation and differentiation of infused MSCs. Our findings support the neuroprotective response and efficacy of MSCs after transplantation in TBI mice, and MSCs may serve as potential therapeutic candidates in regenerative medicine.

SCF + G-CSF treatment in the chronic phase of severe TBI enhances axonal sprouting in the spinal cord and synaptic pruning in the hippocampus

Traumatic brain injury (TBI) is a major cause of long-term disability in young adults. An evidence-based treatment for TBI recovery, especially in the chronic phase, is not yet available. Using a severe TBI mouse model, we demonstrate that the neurorestorative efficacy of repeated treatments with stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF) (SCF + G-CSF) in the chronic phase is superior to SCF + G-CSF single treatment. SCF + G-CSF treatment initiated at 3 months post-TBI enhances contralesional corticospinal tract sprouting into the denervated side of the cervical spinal cord and re-balances the TBI-induced overgrown synapses in the hippocampus by enhancing microglial function of synaptic pruning. These neurorestorative changes are associated with SCF + G-CSF-improved somatosensory-motor function and spatial learning. In the chronic phase of TBI, severe TBI-caused microglial degeneration in the cortex and hippocampus is ameliorated by SCF + G-CSF treatment. These findings reveal the therapeutic potential and possible mechanism of SCF + G-CSF treatment in brain repair during the chronic phase of severe TBI.

Neuroprotective effect of minocycline against acute brain injury in clinical practice: A systematic review

Acute brain injury is a leading cause of morbidity and mortality worldwide. The term is inclusive of traumatic brain injury, cerebral ischemia, subarachnoid hemorrhage, and intracerebral hemorrhage. Current pharmacologic treatments have had minimal effect on improving neurological outcomes leading to a significant interest in the development neuroprotective agents. Minocycline is a second-generation tetracycline with high blood brain barrier penetrance due to its lipophilic properties. It functions across multiple molecular pathways involved in secondary-injury cascades following acute brain injury. Animal model studies suggest that minocycline might lead to improved neurologic outcomes, but few such trials exist in humans. Clinical investigations have been limited to small randomized trials in ischemic stroke patients which have not demonstrated a clear advantage in neurologic outcomes, but also have not been sufficiently powered to draw definitive conclusions. The potential neuroprotective effect of minocycline in the setting of traumatic brain injury, subarachnoid hemorrhage, and intracerebral hemorrhage have all been limited to pilot studies with phase II/III investigations pending. The authors aim to synthesize what is currently known about minocycline as a neuroprotective agent against acute brain injury in humans.