Traumatic brain injury

Exploring Pharmacological Mechanisms of Xuefu Zhuyu Decoction in the Treatment of Traumatic Brain Injury via a Network Pharmacology Approach

Objectives

Xuefu Zhuyu decoction (XFZYD), a traditional Chinese medicine (TCM) formula, has been demonstrated to be effective for the treatment of traumatic brain injury (TBI). However, the underlying pharmacological mechanisms remain unclear. This study aims to explore the potential action mechanisms of XFZYD in the treatment of TBI and to elucidate the combination principle of this herbal formula.

Methods

A network pharmacology approach including ADME (absorption, distribution, metabolism, and excretion) evaluation, target prediction, known therapeutic targets collection, network construction, and molecule docking was used in this study.

Results

A total of 119 bioactive ingredients from XFZYD were predicted to act on 47 TBI associated specific proteins which intervened in several crucial pathological processes including apoptosis, inflammation, antioxidant, and axon genesis. Almost each of the bioactive ingredients targeted more than one protein. The molecular docking simulation showed that 91 pairs of chemical components and candidate targets had strong binding efficiencies. The “Jun”, “Chen”, and “Zuo-Shi” herbs from XFZYD triggered their specific targets regulation, respectively.

Conclusion

Our work successfully illuminates the “multicompounds, multitargets” therapeutic action of XFZYD in the treatment of TBI by network pharmacology with molecule docking method. The present work may provide valuable evidence for further clinical application of XFZYD as therapeutic strategy for TBI treatment.

Estimation of Arterial Carbon Dioxide Based on End-Tidal Gas Pressure and Oxygen Saturation

Arterial blood gas (ABG) analysis is the traditional method for measuring the partial pressure of carbon dioxide. In mechanically ventilated patients a continuous noninvasive monitoring of carbon dioxide would obviously be attractive. In the current study, we present a novel formula for noninvasive estimation of arterial carbon dioxide. Eighty-one datasets were collected from 19 anesthetized and mechanically ventilated pigs. Eleven animals were mechanically ventilated without interventions. In the remaining eight pigs the partial pressure of carbon dioxide was manipulated. The new formula (Formula 1) is PaCO₂ = PETCO₂ + k(PETO₂ − PaO₂) where PaO₂ was calculated from the oxygen saturation. We tested the agreements of this novel formula and compared it to a traditional method using the baseline PaCO₂ − ETCO₂ gap added to subsequently measured, end-tidal carbon dioxide levels (Formula 2). The mean difference between PaCO₂ and calculated carbon dioxide (Formula 1) was 0.16 kPa (±SE 1.17). The mean difference between PaCO₂ and carbon dioxide with Formula 2 was 0.66 kPa (±SE 0.18). With a mixed linear model excluding cases with cardiorespiratory collapse, there was a significant difference between formulae (p < 0.001), as well as significant interaction between formulae and time (p < 0.001). In this preliminary animal study, this novel formula appears to have a reasonable agreement with PaCO₂ values measured with ABG analysis, but needs further validation in human patients.

Indicators of long-term return to work after severe traumatic brain injury: A cohort study

BACKGROUND

Return to work (RTW) is a major objective in the rehabilitation of individuals with severe traumatic brain injury (TBI). Implications for long-term occupational integration (beyond 5 years) have rarely been studied.

OBJECTIVE

The objective was to assess long-term RTW and the associated factors after severe TBI.

MATERIAL AND METHODS

Retrospective analysis of a cohort of individuals 16 to 60 years old admitted to hospital after severe TBI from 2005 to 2009 and followed prospectively. Medical and occupational data were collected from medical files and by systematic telephone interview to assess outcome at a minimum of 6 years post-trauma. Factors associated with RTW were investigated by multivariable regression analysis, estimating prevalence ratios (PRs) and 95% confidence intervals (CIs). A proportional hazards model was used to study RTW delay, estimating hazard ratios (HRs).

RESULTS

Among the 91 individuals included (mean [SD] age 28.5 [11.3] years; 79% male), 63.7% returned to work after a mean of about 20 months, and 57.1% were still working at the time of the survey. Factors significantly associated with RTW on multivariable analysis were higher educational level (adjusted PR, 1.53; 95% CI, 1.15 to 2.03), absence of motor disability (adjusted PR, 1.82; 1.12 to 2.95) and behavioural disorder (adjusted PR, 1.26; 1.01 to 1.60), as well as disabled worker status (adjusted PR, 1.26; 1.01 to 1.60) (likelihood of the multivariate analysis model 53.1). Delayed RTW was associated with health insurance payments (adjusted HR, 0.40; 95% CI, 0.22 to 0.71), motor disability (adjusted HR, 0.34; 0.15 to 0.76), low educational level (adjusted HR, 2.20; 1.06 to 4.56) and moderate disability on the Extended Glasgow Outcome Scale (adjusted HR, 0.49; 0.27 to 0.91) (likelihood of the multivariate analysis model 335.5).

CONCLUSION

Individuals with the most severe TBI are able to RTW and remain in work. This study highlights the multiple determinants involved in RTW and the role of socioenvironmental factors.

Glibenclamide Produces Region-Dependent Effects on Cerebral Edema in a Combined Injury Model of Traumatic Brain Injury and Hemorrhagic Shock in Mice

Cerebral edema is critical to morbidity/mortality in traumatic brain injury (TBI) and is worsened by hypotension. Glibenclamide may reduce cerebral edema by inhibiting sulfonylurea receptor-1 (Sur1); its effect on diffuse cerebral edema exacerbated by hypotension/resuscitation is unknown. We aimed to determine if glibenclamide improves pericontusional and/or diffuse edema in controlled cortical impact (CCI) (5m/sec, 1 mm depth) plus hemorrhagic shock (HS) (35 min), and compare its effects in CCI alone. C57BL/6 mice were divided into five groups (n = 10/group): naïve, CCI+vehicle, CCI+glibenclamide, CCI+HS+vehicle, and CCI+HS+glibenclamide. Intravenous glibenclamide (10 min post-injury) was followed by a subcutaneous infusion for 24 h. Brain edema in injured and contralateral hemispheres was subsequently quantified (wet-dry weight). This protocol brain water (BW) = 80.4% vehicle vs. 78.3% naïve, p < 0.01) but was not reduced by glibenclamide (I%BW = 80.4%). Ipsilateral edema also developed in CCI alone (I%BW = 80.2% vehicle vs. 78.3% naïve, p < 0.01); again unaffected by glibenclamide (I%BW = 80.5%). Contralateral (C) %BW in CCI+HS was increased in vehicle (78.6%) versus naive (78.3%, p = 0.02) but unchanged in CCI (78.3%). At 24 h, glibenclamide treatment in CCI+HS eliminated contralateral cerebral edema (C%BW = 78.3%) with no difference versus naïve. By 72 h, contralateral cerebral edema had resolved (C%BW = 78.5 ± 0.09% vehicle vs. 78.3 ± 0.05% naïve). Glibenclamide decreased 24 h contralateral cerebral edema in CCI+HS. This beneficial effect merits additional exploration in the important setting of TBI with polytrauma, shock, and resuscitation. Contralateral edema did not develop in CCI alone. Surprisingly, 24 h of glibenclamide treatment failed to decrease ipsilateral edema in either model. Interspecies dosing differences versus prior studies may play an important role in these findings. Mechanisms underlying brain edema may differ regionally, with pericontusional/osmolar swelling refractory to glibenclamide but diffuse edema (via Sur1) from combined injury and/or resuscitation responsive to this therapy. TBI phenotype may mandate precision medicine approaches to treat brain edema.

Prospective evaluation of the Quality of Life after Brain Injury (QOLIBRI) score: minor differences in patients with major versus no or mild traumatic brain injury at one-year follow up

Background

The Quality of Life after Brain Injury (QOLIBRI) score was developed to assess disease-specific health-related quality of life (HRQoL) after traumatic brain injury (TBI). So far, validation studies on the QOLIBRI were only conducted in cohorts with traumatic brain injury. This study investigated the longer-term residuals in severely injured patients, focusing specifically on the possible impact of major TBI.

Methods

In a prospective questionnaire investigation, 199 survivors with an injury severity score (ISS) > 15 participated in one-year follow-up. Patients who had sustained major TBI (abbreviated injury scale, AIS head > 2) were compared with patients who had no or only mild TBI (AIS head ≤ 2). Univariate analysis (ANOVA, Cohen’s kappa, Pearson’s r) and stepwise linear regression analysis (B with 95% CI, R, R²) were used.

Results

The total QOLIBRI revealed no differences in one-year outcomes between patients with versus without major TBI (75 and 76, resp.; p = 0.68). With regard to the cognitive subscore, the group with major TBI demonstrated significantly more limitations than the one with no or mild TBI (p < 0.05). The AIS head correlated significantly with the cognitive dimension of the QOLIBRI (r = − 0.16; p < 0.05), but not with the mental components of the SF-36 or the TOP. In multivariate analysis, the influence of the severity of head injury (AIS head) on total QOLIBRI was weaker than that of injured extremities (R² = 0.02; p < 0.05 vs. R² = 0.04; p = 0.001) and equal to the QOLIBRI cognitive subscore (R² = 0.03, p < 0.01 each).

Conclusions

Given the unexpected result of similar mean QOLIBRI total score values and only minor differences in cognitive deficits following major trauma independently of whether patients sustained major brain injury or not, further studies should investigate whether the QOLIBRI actually has the discriminative capacity to detect specific residuals of major TBI. In effect, the score appears to indicate mental deficits following different types of severe trauma, which should be evaluated in more detail.

Trial registration

NCT02165137; retrospectively registered 11 June 2014.

Interactive iBook-Based Patient Education in a NeuroTrauma Clinic

BACKGROUND

Traumatic brain injury (TBI) is a leading cause of death and disability in the United States. Educational interventions may alleviate the burden of TBI for patients and their families. Interactive modalities that involve engagement with the educational material may enhance patient knowledge acquisition when compared to static text-based educational material.

OBJECTIVE

To determine the effects of educational interventions in the outpatient setting on self-reported patient knowledge, with a focus on iPad-based (Apple, Cupertino, California) interactive modules.

METHODS

Patients and family members presenting to a NeuroTrauma clinic at a tertiary care academic medical center completed a presurvey assessing baseline knowledge of TBI or concussion, depending on the diagnosis. Subjects then received either an interactive iBook (Apple) on TBI or concussion, or an informative pamphlet with identical information in text format. Subjects then completed a postsurvey prior to seeing the neurosurgeon.

RESULTS

All subjects (n = 152) significantly improved on self-reported knowledge measures following administration of either an iBook (Apple) or pamphlet (P < .01, 95% confidence interval [CI]). Subjects receiving the iBook (n = 122) performed significantly better on the postsurvey (P < .01, 95% CI), despite equivalent presurvey scores, when compared to those receiving pamphlets (n = 30). Lastly, patients preferred the iBook to pamphlets (P < .01, 95% CI).

CONCLUSION

Educational interventions in the outpatient NeuroTrauma setting led to significant improvement in self-reported measures of patient and family knowledge. This improved understanding may increase compliance with the neurosurgeon's recommendations and may help reduce the potential anxiety and complications that arise following a TBI.

Andrographolide protects mouse astrocytes against hypoxia injury by promoting autophagy and S100B expression

Andrographolide (ANDRO) has been studied for its immunomodulation, anti-inflammatory, and neuroprotection effects. Because brain hypoxia is the most common factor of secondary brain injury after traumatic brain injury, we studied the role and possible mechanism of ANDRO in this process using hypoxia-injured astrocytes. Mouse cortical astrocytes C8-D1A (astrocyte type I clone from C57/BL6 strains) were subjected to 3 and 21% of O₂ for various times (0–12 h) to establish an astrocyte hypoxia injury model in vitro. After hypoxia and ANDRO administration, the changes in cell viability and apoptosis were assessed using CCK-8 and flow cytometry. Expression changes in apoptosis-related proteins, autophagy-related proteins, main factors of JNK pathway, ATG5, and S100B were determined by western blot. Hypoxia remarkably damaged C8-D1A cells evidenced by reduction of cell viability and induction of apoptosis. Hypoxia also induced autophagy and overproduction of S100B. ANDRO reduced cell apoptosis and promoted cell autophagy and S100B expression. After ANDRO administration, autophagy-related proteins, S-100B, JNK pathway proteins, and ATG5 were all upregulated, while autophagy-related proteins and s100b were downregulated when the jnk pathway was inhibited or ATG5 was knocked down. ANDRO conferred a survival advantage to hypoxia-injured astrocytes by reducing cell apoptosis and promoting autophagy and s100b expression. Furthermore, the promotion of autophagy and s100b expression by ANDRO was via activation of jnk pathway and regulation of ATG5.

Eyeball pressure stimulation induces subtle sympathetic activation in patients with a history of moderate or severe traumatic brain injury

OBJECTIVE

After traumatic brain injury (TBI), there may be persistent central-autonomic-network (CAN) dysfunction causing cardiovascular-autonomic dysregulation. Eyeball-pressure-stimulation (EPS) normally induces cardiovagal activation. In patients with a history of moderate or severe TBI (post-moderate-severe-TBI), we determined whether EPS unveils cardiovascular-autonomic dysregulation.

METHODS

In 51 post-moderate-severe-TBI patients (32.7 ± 10.5 years old, 43.1 ± 33.4 months post-injury), and 30 controls (29.1 ± 9.8 years), we recorded respiration, RR-intervals (RRI), systolic and diastolic blood-pressure (BPsys, BPdia), before and during EPS (120 sec; 30 mmHg), using an ocular-pressure-device (Okulopressor®). We calculated spectral-powers of mainly sympathetic low (LF: 0.04-0.15 Hz) and parasympathetic high (HF: 0.15-0.5 Hz) frequency RRI-fluctuations, sympathetically mediated LF-powers of BPsys, and calculated normalized (nu) LF- and HF-powers of RRI. We compared parameters between groups before and during EPS by repeated-measurement-analysis-of-variance with post-hoc analysis (significance: p < 0.05).

RESULTS

At rest, sympathetically mediated LF-BPsys-powers were significantly lower in the patients than the controls. During EPS, only controls significantly increased RRIs and parasympathetically mediated HFnu-RRI-powers, but decreased LF-RRI-powers, LFnu-RRI-powers, and LF-BPsys-powers; in contrast, the patients slightly though significantly increased BPsys upon EPS, without changing any other parameter.

CONCLUSIONS

In post-moderate-severe-TBI patients, autonomic BP-modulation was already compromised at rest. During EPS, our patients failed to activate cardiovagal modulation but slightly increased BPsys, indicating persistent CAN dysregulation.

SIGNIFICANCE

Our findings unveil persistence of subtle cardiovascular-autonomic dysregulation even years after TBI.

Helicopter Transportation Increases Intracranial Pressure: a Proof-of-Principle Study

OBJECTIVE

After severe (primary) brain injury, Dutch physician-based helicopter emergency medical services start therapy to lower the intracranial pressure (ICP) on scene to stop or delay secondary brain injury. In some cases, helicopter transportation to the nearest level 1 trauma center is indicated. During transportation, the head-down position may counteract the ICP-lowering strategies because of venous blood pooling in the head. To examine this theory, we measured the optic nerve sheath diameter (ONSD) during helicopter transport in healthy volunteers.

METHODS

The ONSD was measured by ultrasound in healthy volunteers during helicopter liftoff and acceleration in the supine position or with a raised headrest.

RESULTS

In this proof-of-principle study, the ONSD increased during helicopter acceleration (-9° Trendelenburg, mean = 5.6 ± .3 mm) from baseline (0° supine position, mean = 5.0 ± .4 mm). After headrest elevation (20°-25°), the ONSD did not increase during helicopter acceleration (mean ONSD = 5.0 ± .5 mm).

CONCLUSION

ONSD and ICP seem to increase during helicopter transportation in -9° head-down (Trendelenburg) position. By raising the headrest of the gurney before liftoff, these effects can be prevented.

Automatic evaluation of traumatic brain injury based on terahertz imaging with machine learning

The imaging diagnosis and prognostication of different degrees of traumatic brain injury (TBI) is very important for early care and clinical treatment. Especially, the exact recognition of mild TBI is the bottleneck for current label-free imaging technologies in neurosurgery. Here, we report an automatic evaluation method for TBI recognition with terahertz (THz) continuous-wave (CW) transmission imaging based on machine learning (ML). We propose a new feature extraction method for biological THz images combined with the transmittance distribution features in spatial domain and statistical distribution features in normalized gray histogram. Based on the extracted feature database, ML algorithms are performed for the classification of different degrees of TBI by feature selection and parameter optimization. The highest classification accuracy is up to 87.5%. The area under the curve (AUC) scores of the receiver operating characteristics (ROC) curve are all higher than 0.9, which shows this evaluation method has a good generalization ability. Furthermore, the excellent performance of the proposed system in the recognition of mild TBI is analyzed by different methodological parameters and diagnostic criteria. The system can be extensible to various diseases and will be a powerful tool in automatic biomedical diagnostics.

Effect of Cerebral Perfusion Pressure on Acute Respiratory Distress Syndrome

BACKGROUND

Increased cerebral perfusion pressure (CPP)>70 mmHg has been associated with acute respiratory distress syndrome (ARDS) after traumatic brain injury (TBI). Since this reported association, significant changes in ventilation strategies and fluid management have been accepted as routine critical care. Recently, individualized perfusion targets using autoregulation monitoring suggest CPP titration>70 mmHg. Given these clinical advances, the association between ARDS and increased CPP requires further delineation.

OBJECTIVE

To determine the association between ARDS and increased CPP after TBI.

METHODS

We conducted a single-center historical cohort study investigating the association of increased CPP and ARDS after TBI. We collected demographic data and physiologic data for CPP, intracranial pressure, mechanical ventilation, cumulative fluid balance and delta/driving pressure (ΔP). We collected outcomes measures pertaining to duration of ventilation, intensive care unit admission length, hospitalization length and 6-month neurological outcome.

RESULTS

In total, 113 patients with severe TBI and multimodal neuromonitoring were included. In total, 16 patients (14%) developed ARDS according to the Berlin definition. There was no difference in the mean CPP during the first 7 days of admission between patients who developed ARDS (74 mmHg SD 18 vs. 73 mmHg SD 18, p=0.86) versus those who did not. Patients who developed ARDS had a higher ΔP (15 mmHg [5] vs. 12 mmHg [4], p=0.016) and lower lung compliance (35 ml/cmH2O [10] vs. 49 ml/cmH2O [18], p=0.024) versus those who did not.

CONCLUSION

We did not observe an association between increased CPP and ARDS. Patients with ARDS had higher ΔP and lower lung compliance.

Is it possible to recover from traumatic brain injury and a Glasgow coma scale score of 3 at emergency department presentation?

INTRODUCTION

A Glasgow Coma Scale (GCS) score of 3 on presentation in patients with traumatic brain injury (TBI) portends a poor prognosis. Consequently, there is often a tendency to treat these patients less aggressively because of low expectations for a good outcome.

METHODS AND RESULTS

We performed a retrospective review of patients with TBI and a GCS score of 3. Patients were divided into 2 groups based on Glasgow Outcome Scale (GOS): Group 1 (GOS=1-3) and Group 2 (GOS=4-5). A total of 62 patients were included. The overall mortality rate was 80.6%. At 6-month, 9 patients (14.5%) achieved a GOS 4-5. Compared to Group 2 (n=9), Group 1 (n=53) had higher average APACHE IV score (104±19 vs 89±27, p=0.04), more patients with bilateral fixed pupils (59% vs 22%, p=0.04), and higher ICP burden (50±34 vs 0±0, p=0.0001). Using the CRASH calculator, the estimated mortality at 14days was 66% compared to actual mortality of 81%; difference of 15%, (p=0.05), and the estimated GOS 1-3 was 85.5% compared to actual of 85.5%, (p=1.0).

CONCLUSIONS

14.5% of patients with TBI and a GCS of 3 at presentation achieved a good outcome at 6months, and 6.9% of patients with GCS of 3 and bilateral fixed pupils on presentation to the ED achieved a good outcome at 6months.

The ketogenic diet as a treatment for traumatic brain injury: a scoping review

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality worldwide. The ketogenic diet (KD) has been identified as a potential therapy to enhance recovery after TBI. The purpose of this study is to complete a scoping review and synthesize the evidence regarding the KD and its therapeutic effects in TBI. The methodological framework of Arksey and O'Malley was employed. Databases searched include Medline, EMBASE, CCRCT, CINAHL and WebOfScience. Two reviewers independently screened titles, abstracts and full texts in a two-step screening protocol to determine inclusion. Abstracted data included study setting and therapeutic mechanism. The KD was demonstrated to reduce cerebral oedema, apoptosis, improve cerebral metabolism and behavioural outcomes in rodent TBIs. Additionally, the KD affected rodent TBIs in an age-dependent manner. Due to a lack of relevant outcome measures, the human trials did not establish much evidence with respect to the KD as a treatment for TBI; only its safety was established. The KD is an effective treatment for TBI recovery in rats and shows potential in humans. Future research should aim to better elucidate the KD's mechanisms of action in human TBIs and determine if the KD's effectiveness on clinical outcomes can be reproduced in humans.

Effect of in vitro storage duration on measured mechanical properties of brain tissue

Accurate characterization of the mechanical properties of brain tissue is essential for understanding the mechanisms of traumatic brain injuries and developing protective gears or facilities. However, how storage conditions might affect the mechanical properties of brain tissue remains unclear. The objective of this study is to investigate the effect of in vitro storage duration on the mechanical performance of brain tissue since measurements are usually carried out in vitro. Differential Scanning Calorimetry (DSC) measurements and uniaxial compression mechanical experiments are carried out. The results indicate that, for brain tissue stored at 1 °C without any liquid medium, the bio-molecular interactions and the mechanical strength of both white and grey matter deteriorate with prolonged storage duration. Transmission Electron Microscopy (TEM) results reveal the degeneration of myelin sheaths and the vacuolization of cristae with prolonged storage duration, suggesting that the in vitro storage duration should be carefully controlled. The findings from this study might facilitate the development of guidelines and standards for the in vitro storage of brain tissue.

Italian guidelines on the assessment and management of pediatric head injury in the emergency department

OBJECTIVE

We aim to formulate evidence-based recommendations to assist physicians decision-making in the assessment and management of children younger than 16 years presenting to the emergency department (ED) following a blunt head trauma with no suspicion of non-accidental injury.

METHODS

These guidelines were commissioned by the Italian Society of Pediatric Emergency Medicine and include a systematic review and analysis of the literature published since 2005. Physicians with expertise and experience in the fields of pediatrics, pediatric emergency medicine, pediatric intensive care, neurosurgery and neuroradiology, as well as an experienced pediatric nurse and a parent representative were the components of the guidelines working group. Areas of direct interest included 1) initial assessment and stabilization in the ED, 2) diagnosis of clinically important traumatic brain injury in the ED, 3) management and disposition in the ED. The guidelines do not provide specific guidance on the identification and management of possible associated cervical spine injuries. Other exclusions are noted in the full text.

CONCLUSIONS

Recommendations to guide physicians practice when assessing children presenting to the ED following blunt head trauma are reported in both summary and extensive format in the guideline document.

Risk of Erectile Dysfunction After Traumatic Brain Injury: A Nationwide Population-Based Cohort study in Taiwan

Introduction:

In our study, we aimed to investigate the association between a traumatic brain injury (TBI) and subsequent erectile dysfunction (ED). This is a population-based study using the claims dataset from The National Health Insurance Research Database.

Methods:

We included 72,642 patients with TBI aged over 20 years, retrospectively, selected from the longitudinal health insurance database during 2000–2010, according to the ICD-9-CM. The control group consisted of 217,872 patients without TBI that were randomly chosen from the database at a ratio of 1:3, with age- and index year matched. Cox proportional hazards analysis was used to estimate the association between the TBI and subsequent ED.

Results:

After a 10-year follow-up, the incidence rate of ED was higher in the TBI patients when compared with the non-TBI control group (24.66 and 19.07 per 100,000, respectively). Patients with TBI had a higher risk of developing ED than the non-TBI cohort after the adjustment of the confounding factors, such as age, comorbidity, residence of urbanization and locations, seasons, level of care, and insured premiums (adjusted hazard ratio (HR) = 2.569, 95% CI [1.890, 3.492], p < .001).

Conclusion:

This is the first study using a comprehensive nationwide database to analyze the association of ED and TBI in the Asian population. After adjusted the confounding factors, patients with TBI have a significantly higher risk of developing ED, especially organic ED, than the general population. This finding might remind clinicians that it’s crucial in early identification and treatment of ED in post-TBI patients.

Diffuse traumatic brain injury in the mouse induces a transient proliferation of oligodendrocyte progenitor cells in injured white matter tracts

BACKGROUND

Injury to the white matter may lead to impaired neuronal signaling and is commonly observed following traumatic brain injury (TBI). Although endogenous repair of TBI-induced white matter pathology is limited, oligodendrocyte progenitor cells (OPCs) may be stimulated to proliferate and regenerate functionally myelinating oligodendrocytes. Even though OPCs are present throughout the adult brain, little is known about their proliferative activity following axonal injury caused by TBI.

OBJECTIVE

We hypothesized that central fluid percussion injury (cFPI) in mice, a TBI model causing wide-spread axonal injury, results in OPC proliferation.

METHODS

Proliferation of OPCs was evaluated in 27 cFPI mice using 5-ethynyl-2'-deoxyuridine (EdU) labeling and a cell proliferation assay at 2 (n = 9), 7 (n = 8) and 21 (n = 10) days post injury (dpi). Sham-injured mice (n = 14) were used as controls. OPC proliferation was quantified by immunohistochemistry using the OPC markers NG2 and Olig2 in several white matter loci including the corpus callosum, external capsule, fimbriae, the internal capsule and cerebral peduncle.

RESULTS

The number of EdU/DAPI/Olig2-positive cells were increased in the cFPI group compared to sham-injured animals at 7 days post-injury (dpi; p≤0.05) in the majority of white matter regions. The OPC proliferation had subsided by 21 dpi. The number of EdU/DAPI/NG2 cells was also increase at 7 dpi in the external capsule and fimbriae.

CONCLUSION

These results suggest that traumatic axonal injury in the mouse induces a transient proliferative response of residing OPCs. These proliferating OPCs may replace dead oligodendrocytes and contribute to remyelination, which needs evaluation in future studies.

Highly Integrated MEMS-ASIC Sensing System for Intracorporeal Physiological Condition Monitoring

In this paper, a highly monolithic-integrated multi-modality sensor is proposed for intracorporeal monitoring. The single-chip sensor consists of a solid-state based temperature sensor, a capacitive based pressure sensor, and an electrochemical oxygen sensor with their respective interface application-specific integrated circuits (ASICs). The solid-state-based temperature sensor and the interface ASICs were first designed and fabricated based on a 0.18-μm 1.8-V CMOS (complementary metal-oxide-semiconductor) process. The oxygen sensor and pressure sensor were fabricated by the standard CMOS process and subsequent CMOS-compatible MEMS (micro-electromechanical systems) post-processing. The multi-sensor single chip was completely sealed by the nafion, parylene, and PDMS (polydimethylsiloxane) layers for biocompatibility study. The size of the compact sensor chip is only 3.65 mm × 1.65 mm × 0.72 mm. The functionality, stability, and sensitivity of the multi-functional sensor was tested ex vivo. Cytotoxicity assessment was performed to verify that the bio-compatibility of the device is conforming to the ISO 10993-5:2009 standards. The measured sensitivities of the sensors for the temperature, pressure, and oxygen concentration are 10.2 mV/°C, 5.58 mV/kPa, and 20 mV·L/mg, respectively. The measurement results show that the proposed multi-sensor single chip is suitable to sense the temperature, pressure, and oxygen concentration of human tissues for intracorporeal physiological condition monitoring.

Cellular therapy for traumatic neurological injury

Neurological injury is the primary lethal mechanism of injury in children, and the primary etiology of long-term disability after trauma. Laboratories and clinical/translational teams have sought to develop stem/progenitor cell therapies to improve recovery in a clinical setting in which there is no significant reparative option. While none of these treatments are currently standard therapeutics, phase IIb clinical trials are underway in both adults and children in severe traumatic brain injury (TBI) and phase I/IIa trials in spinal cord injury. This review will characterize the cell therapy strategies: cell replacement and tissue integration vs. immunomodulation/enhanced endogenous tissue repair. TBI is somewhat different from other central nervous system injuries (spinal cord injury and stroke), in that TBI is a diffuse injury, whereas spinal cord injury and stroke are anatomically discrete. Importantly, this drives cell therapy approaches, as TBI is less apt to be treatable with a local cell replacement intervention. More localized injuries may be more amenable to local approaches and cell replacement to bridge focal gaps. This review focuses on a few reports in the field that highlight areas of progress, but is not intended to be a comprehensive survey of the state of regenerative medicine for neurological injuries.

Inflammasomes in CNS Diseases

Neuroinflammation is a common pathological feature in almost all neurological diseases and is a response triggered as a consequence of the chronic activation of the innate immune response in the CNS against a variety of stimuli, including infection, traumatic brain injury, toxic metabolites, aggregated proteins, or autoimmunity. Crucial mediators of this neurinflammatory process are the intracellular protein complexes known as inflammasomes which can be triggered by pathogens as well as pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). However, chronic inflammasome activation can eventually result in cellular death and tissue damage, leading to the release of DAMPs that can reactivate the inflammasome, thereby propagating a vicious cycle of inflammation. The primary cells involved in CNS inflammasome activation are the immunocompetent microglia and the infiltrating macrophages into the CNS. However, astrocytes and neurons also express inflammasomes, and the understanding of how they are engaged in the pathogenesis of a variety of neurological diseases is crucial to develop effective therapeutic approaches for CNS pathologies that are propagated by chronic inflammasome activation. This chapter covers the activation mechanisms of relevant inflammasomes in the brain and summarizes their roles in the pathogenesis and progression of different neurological conditions.

Factors Affecting Functional Outcome after Decompressive Craniectomy Performed for Traumatic Brain Injury: A Retrospective, Cross-sectional Study

Background:

Factors affecting functional outcome after decompressive craniectomy (DC) performed for traumatic brain injury (TBI) remain poorly understood.

Methods:

We conducted a retrospective study of all patients who underwent primary DC for TBI at our hospital between 2010 and 2014. Multivariate regression analyses were used to determine the predictors of functional outcome and overall survival.

Results:

A total of 98 patients with severe (n = 81, 82.6%) or moderate (n = 17, 17.4%) TBI underwent primary DC and were included in this study. The 30-day and overall mortality rates were 15.3% and 25.5%, respectively. At a median follow-up of 90 (interquartile range (IQR): 38–180) days, median Karnofsky Performance Status (KPS) and Glasgow outcome scale-extended (GOSE) scores were 50 (IQR: 20–70) and 5 (IQR: 3–7), respectively. Young age and severe TBI were predictors of mortality. Glasgow coma scale (GCS) score on discharge was a strong predictor of KPS and GOSE scores.

Conclusion:

Primary DC afforded an acceptable functional outcome (GOSE score ≥5) in 45.9% of patients. Young age and lower GCS at presentation were associated with worse survival. GCS score on discharge was a strong predictor of functional outcome.

Piezo type mechanosensitive ion channel component 1 functions as a regulator of the cell fate determination of mesenchymal stem cells

The extracellular environment regulates the dynamic behaviors of cells. However, the effects of hydrostatic pressure (HP) on cell fate determination of mesenchymal stem cells (MSCs) are not clearly understood. Here, we established a cell culture chamber to control HP. Using this system, we found that the promotion of osteogenic differentiation by HP is depend on bone morphogenetic protein 2 (BMP2) expression regulated by Piezo type mechanosensitive ion channel component 1 (PIEZO1) in MSCs. The PIEZO1 was expressed and induced after HP loading in primary MSCs and MSC lines, UE7T-13 and SDP11. HP and Yoda1, an activator of PIEZO1, promoted BMP2 expression and osteoblast differentiation, whereas inhibits adipocyte differentiation. Conversely, PIEZO1 inhibition reduced osteoblast differentiation and BMP2 expression. Furthermore, Blocking of BMP2 function by noggin inhibits HP induced osteogenic maker genes expression. In addition, in an in vivo model of medaka with HP loading, HP promoted caudal fin ray development whereas inhibition of piezo1 using GsMTx4 suppressed its development. Thus, our results suggested that PIEZO1 is responsible for HP and could functions as a factor for cell fate determination of MSCs by regulating BMP2 expression.

Does Red Cell Distribution Width Predict Outcome in Traumatic Brain Injury: Comparison to Corticosteroid Randomization After Significant Head Injury

Background

Traumatic brain injury (TBI) is a leading cause of death and disability. The role of red cell distribution width (RDW) as a prognostic biomarker for outcome in TBI patients is unknown. Based on the corticosteroid randomization after significant head injury (CRASH) trial database, a prognosis calculator (CRASH) has been developed for outcome prediction in TBI. The objectives of this study are to investigate the association between RDW on day 1 of TBI and outcome, and to compare outcome prediction from RDW to that from CRASH.

Methods

We performed a retrospective review of patients with TBI and a Glasgow coma scale (GCS) score of 14 or less. Day 1 RDW and CRASH data were extracted. CRASH was calculated for each patient. Outcome was defined as mortality at 14 days and GOS at 6 months, with poor outcome defined as GOS of 1 - 3. Patients were stratified according to RDW values into six groups, and according to CRASH values into six groups.

Results

A total of 416 patients with TBI were included, with 339 survivors (S) and 77 non-survivors (NS). Compared to survivors, non-survivors were of similar age in years (58 ± 23 vs. 58 ± 23, P = 1.0), had lower GCS scores (5 ± 3 vs. 12 ± 3, P = 0.0001), similar RDW (14.0 ± 1.2 vs. 13.9 ± 1.5, P = 0.6), and higher CRASH values (68 ± 26 vs. 24 ± 22, P = 0.0001). Estimating the receiver-operating characteristic (ROC) area under the curve (AUC) showed that CRASH was a significantly better predictor of mortality compared to RDW (AUC = 0.91 ± 0.01 for CRASH compared to 0.66 ± 0.03 for RDW; P < 0.0001). In addition, CRASH was a better predictor of neurologic outcome compared to RDW (AUC = 0.85 ± 0.02 for CRASH compared to 0.76 ± 0.03 for RDW; P = 0.005).

Conclusions

CRASH calculator was a strong predictor of mortality in patients with TBI. RDW on day 1 did not differ between survivors and non-survivors, and was a poor predictor of mortality. Both RDW on day 1 and CRASH calculator are good predictors of 6-month outcome in TBI patients, although CRASH calculator remains a better predictor.

Chronic Subdural Hematoma: A Perspective on Subdural Membranes and Dementia

OBJECTIVE

To review the complex pathogenesis of the subdural membrane and the link between head trauma, dementia, and dural lymphatics.

METHODS

A thorough literature search of published English-language articles was performed using PubMed, Ovid, and Cochrane databases.

RESULTS

Chronic subdural hematoma (cSDH) is a common intracranial pathology and a leading cause of reversible dementia. cSDH is projected to affect at least 60,000 new individuals in the United States annually by 2030. This condition can result from mild to moderate head trauma that leads to hemorrhaging in the dura-arachnoid interface. The short-term and long-term effects of cSDH and the subdural membrane on the pathogenesis of dementia and the newly discovered dural lymphatics is a topic of increasing importance.

CONCLUSIONS

Further research into the possible link between traumatic brain injury and cSDH in particular and dural lymphatics and intracranial fluid dynamics is warranted.

Current Opportunities for Clinical Monitoring of Axonal Pathology in Traumatic Brain Injury

Traumatic brain injury (TBI) is a multidimensional and highly complex disease commonly resulting in widespread injury to axons, due to rapid inertial acceleration/deceleration forces transmitted to the brain during impact. Axonal injury leads to brain network dysfunction, significantly contributing to cognitive and functional impairments frequently observed in TBI survivors. Diffuse axonal injury (DAI) is a clinical entity suggested by impaired level of consciousness and coma on clinical examination and characterized by widespread injury to the hemispheric white matter tracts, the corpus callosum and the brain stem. The clinical course of DAI is commonly unpredictable and it remains a challenging entity with limited therapeutic options, to date. Although axonal integrity may be disrupted at impact, the majority of axonal pathology evolves over time, resulting from delayed activation of complex intracellular biochemical cascades. Activation of these secondary biochemical pathways may lead to axonal transection, named secondary axotomy, and be responsible for the clinical decline of DAI patients. Advances in the neurocritical care of TBI patients have been achieved by refinements in multimodality monitoring for prevention and early detection of secondary injury factors, which can be applied also to DAI. There is an emerging role for biomarkers in blood, cerebrospinal fluid, and interstitial fluid using microdialysis in the evaluation of axonal injury in TBI. These biomarker studies have assessed various axonal and neuroglial markers as well as inflammatory mediators, such as cytokines and chemokines. Moreover, modern neuroimaging can detect subtle or overt DAI/white matter changes in diffuse TBI patients across all injury severities using magnetic resonance spectroscopy, diffusion tensor imaging, and positron emission tomography. Importantly, serial neuroimaging studies provide evidence for evolving axonal injury. Since axonal injury may be a key risk factor for neurodegeneration and dementias at long-term following TBI, the secondary injury processes may require prolonged monitoring. The aim of the present review is to summarize the clinical short- and long-term monitoring possibilities of axonal injury in TBI. Increased knowledge of the underlying pathophysiology achieved by advanced clinical monitoring raises hope for the development of novel treatment strategies for axonal injury in TBI.

Regulation of Mitochondrial, Cellular, and Organismal Functions by TSPO

In 1999, the enigma of the 18kDa mitochondrial translocator protein (TSPO), also known as the peripheral-type benzodiazepine receptor, was the seeming disparity of the many functions attributed to TSPO, ranging from the potential of TSPO acting as a housekeeping gene at molecular biological levels to adaptations to stress, and even involvement in higher emotional and cognitive functioning, such as anxiety and depression. In the years since then, knowledge regarding the many functions modulated by TSPO has expanded, and understanding has deepened. In addition, new functions could be firmly associated with TSPO, such as regulation of programmed cell death and modulation of gene expression. Interestingly, control by the mitochondrial TSPO over both of these life and death functions appears to include Ca⁺⁺ homeostasis, generation of reactive oxygen species (ROS), and ATP production. Other mitochondrial functions under TSPO control are considered to be steroidogenesis and tetrapyrrole metabolism. As TSPO effects on gene expression and on programmed cell death can be related to the wide range of functions that can be associated with TSPO, several of these five elements of Ca⁺⁺, ROS, ATP, steroids, and tetrapyrroles may indeed form the basis of TSPO's capability to operate as a multifunctional housekeeping gene to maintain homeostasis of the cell and of the whole multicellular organism.

Linguistic Validation of Interactive Educational Interventions in Neurologic Trauma

BACKGROUND

Neurological surgeons oftentimes educate patients and their families on complex medical conditions and treatment options. Time constraints and varied linguistic and cultural backgrounds limit the amount of information that can be disbursed. In this study, we assessed the linguistic validity of interactive educational interventions in non-English-speaking patients with traumatic brain injury (TBI) and concussion and their families.

METHODS

A total of 273 English-, Spanish-, Korean-, and Vietnamese-speaking neurotrauma patients (n =124) and family members (n =149) completed a presurvey to evaluate their incipient understanding, interacted with an iPad-based iBook (Apple) on concussion or TBI in their native language, completed a postsurvey to gauge changes in understanding, and then consulted with their neurosurgeon.

RESULTS

All participants (124 patients and 149 family members) had significantly increased (95% confidence interval [CI], P < 0.01) postsurvey scores (average pre-iBook score, 2.810; average post-iBook score, 4.109), regardless of native language or cultural background. Caucasian participants scored significantly higher than the combination of all ethnicities on both the baseline survey (95% CI, P < 0.01) and the post-iBook survey (95% CI, P < 0.01), and Asian participants scored significantly lower (95% CI, P < 0.05) than the combination regardless of similar baseline scores.

CONCLUSIONS

Interactive iBook-based interventions on concussion and TBI can increase participants' comprehension, improve their comfort with their medical condition and the follow-up care, and enhance communication with their physicians. These findings are linguistically valid irrespective of the participants' native language or cultural background.

Feature clustering of intracranial pressure time series for alarm function estimation in traumatic brain injury

OBJECTIVE

The conventional application of intracranial pressure (ICP) monitoring of traumatic brain injury (TBI) patients consists merely in the acquisition of ICP values in discrete time and their comparison to the established ICP threshold. An exceeding of this threshold triggers a special emergency treatment protocol. This paper addresses the possibility of making use of the rich information latent in the ICP records of known vital and fatal outcomes gathered during real clinical practice of treating TBI patients. Our assumption was that the proposed algorithmic procedure derived from this information could, in addition to ICP monitoring itself, provide a complementary added value. This might help clinicians to make better decisions during a patient's treatment.

APPROACH

We concentrated on studying specific clustering schemes for subsequences of ICP time series. The clusterization problem was formulated for feature vectors which are introduced to represent ICP time subsequences. The ICP transformation to a feature space uses global and local definitions of time subsequences. For clusterization itself, we adopted hierarchical Gaussian mixture models (hGMMs). By using posterior probabilities of the clusters, we introduced three novel alarm functions. We explored two alternative methods of searching for optimum alarm function thresholds (ROC analysis and a novel efficiency measure).

MAIN RESULTS

We performed extensive cross-validation experiments on a clinical retrospective data set. The results of the optimization over several hGMMs, various feature space dimensionality and all the types of the novel alarm functions show the potential of the novel alarm functions for supplementing conventional ICP monitoring.

SIGNIFICANCE

In conclusion, the paper provides a prospective extended ICP monitoring technique for real TBI patients, based on the proposed methodology of ICP subsequence clustering and thresholding of the optimum novel alarm function.

Peroxisome proliferator-activated receptor γ (PPARγ): A master gatekeeper in CNS injury and repair

Peroxisome proliferator-activated receptor γ (PPARγ) is a widely expressed ligand-modulated transcription factor that governs the expression of genes involved in inflammation, redox equilibrium, trophic factor production, insulin sensitivity, and the metabolism of lipids and glucose. Synthetic PPARγ agonists (e.g. thiazolidinediones) are used to treat Type II diabetes and have the potential to limit the risk of developing brain injuries such as stroke by mitigating the influence of comorbidities. If brain injury develops, PPARγ serves as a master gatekeeper of cytoprotective stress responses, improving the chances of cellular survival and recovery of homeostatic equilibrium. In the acute injury phase, PPARγ directly restricts tissue damage by inhibiting the NFκB pathway to mitigate inflammation and stimulating the Nrf2/ARE axis to neutralize oxidative stress. During the chronic phase of acute brain injuries, PPARγ activation in injured cells culminates in the repair of gray and white matter, preservation of the blood-brain barrier, reconstruction of the neurovascular unit, resolution of inflammation, and long-term functional recovery. Thus, PPARγ lies at the apex of cell fate decisions and exerts profound effects on the chronic progression of acute injury conditions. Here, we review the therapeutic potential of PPARγ in stroke and brain trauma and highlight the novel role of PPARγ in long-term tissue repair. We describe its structure and function and identify the genes that it targets. PPARγ regulation of inflammation, metabolism, cell fate (proliferation/differentiation/maturation/survival), and many other processes also has relevance to other neurological diseases. Therefore, PPARγ is an attractive target for therapies against a number of progressive neurological disorders.

Effect of sex and age on traumatic brain injury: a geographical comparative study

Background

Traumatic brain injury (TBI) is a much researched topic in medical health, which requires additional studies to understand various effects of demographic and geographic factors that can assist in developing the most effective treatments. Thousands of people of different ages are suffering from lifelong disabilities, either mild or severe, from TBI and the number is increasing. This study aims to increase our understanding of the effect of sex and age by applying five different statistical methods to evaluate the effect of these covariates on two independent TBI data sets representing patients from different geographical cohorts. A primary data was collected from Bangladesh and it was compared with CRASH (Corticosteroid Randomisation after Significant Head Injury) data, representing various countries around the world.

Methods

The outcome variable for TBI considered in this paper is Glasgow Outcome Scale, which is a four point scale. It was converted to a binary outcome scale for fitting of Fisher’s exact test, a test of proportions and a binary linear model. For analyzing ordinal outcomes, the proportional odds model and the sliding dichotomy model were fitted. As the sample size of the Bangladeshi data set was small, parametric bootstrapping was applied for the consistency of results.

Results

Females were the worse sufferers of TBI compared to men, according to CRASH data set. The old (aged above 58 years) followed by adults (age 25 to 58) were the most vulnerable victims. Interaction effects concluded that old women tended to endure the worst outcomes of TBI. This conclusion came from the CRASH data set representing the world in general, whereas such effects were not present in the Bangladesh data set. Additional application of parametric bootstrapping for the smaller Bangladesh data set did not result into any significant outcome.

Conclusion

The effect of gender and age could be stronger in some countries than others which is driving the significance in CRASH and was not found in Bangladesh. It reflects the necessity of incorporating geographic patterns as well as demographic features of patients while developing treatments and designing clinical trials.

Spinal cord perfusion pressure predicts neurologic recovery in acute spinal cord injury

OBJECTIVE

To determine whether spinal cord perfusion pressure (SCPP) as measured with a lumbar intrathecal catheter is a more predictive measure of neurologic outcome than the conventionally measured mean arterial pressure (MAP).

METHODS

A total of 92 individuals with acute spinal cord injury were enrolled in this multicenter prospective observational clinical trial. MAP and CSF pressure (CSFP) were monitored during the first week postinjury. Neurologic impairment was assessed at baseline and at 6 months postinjury. We used logistic regression, systematic iterations of relative risk, and Cox proportional hazard models to examine hemodynamic patterns commensurate with neurologic outcome.

RESULTS

We found that SCPP (odds ratio 1.039, p = 0.002) is independently associated with positive neurologic recovery. The relative risk for not recovering neurologic function continually increased as individuals were exposed to SCPP below 50 mm Hg. Individuals who improved in neurologic grade dropped below SCPP of 50 mm Hg fewer times than those who did not improve (p = 0.012). This effect was not observed for MAP or CSFP. Those who were exposed to SCPP below 50 mm Hg were less likely to improve from their baseline neurologic impairment grade (p = 0.0056).

CONCLUSIONS

We demonstrate that maintaining SCPP above 50 mm Hg is a strong predictor of improved neurologic recovery following spinal cord injury. This suggests that SCPP (the difference between MAP and CSFP) can provide useful information to guide the hemodynamic management of patients with acute spinal cord injury.

Correlation between connexin and traumatic brain injury in patients

BACKGROUND

Identification of molecular alterations of damaged tissue in patients with neurological disorders can provide novel insight and potential therapeutic target for treatment of the diseases. It has been suggested by animal studies that connexins (CXs), a family of gap junction proteins, could contribute to neuronal cell death and associate with neurological deficits during trauma-induced damage. Nevertheless, whether specific CXs are involved in traumatic brain injury (TBI) has remained unexplored in human patients.

METHODS

In a clinical setting, we performed a correlation study of 131 TBI patients who received brain surgery. CXs (including CX40, CX43, and CX45) were examined in the harvested brain tissues for studying the relationships with the Glasgow Coma Scale scores of the patients.

RESULTS

Specifically, the protein levels of CX43 (negatively) and CX40 (positively) are associated with the extent of disease severity. Meanwhile, the phosphorylation status of CX43 was strongly associated with the severe TBI patients who contain relatively high kinase activities of PKC (protein kinase C) and MAPK (mitogen-activated protein kinase), two possible activators for CX43 phosphorylation.

CONCLUSION

These data highlight that a cluster of connexin family gap junction proteins not previously studied in humans is significantly correlated with the disease progression of TBI.

Metabotropic glutamate receptor 5 deficiency inhibits neutrophil infiltration after traumatic brain injury in mice

Both brain native inflammatory cells and infiltrated peripheral white blood cells (WBCs) are primary participants in the brain inflammatory damage post-TBI. Metabotropic glutamate receptor 5 (mGluR5) has been reported to regulate microglias and astrocytes to affect inflammation after TBI, but its effect on modulating infiltrated peripheral WBCs remains unclear. In a mouse moderate TBI model, we found that mGluR5 knockout (KO) significantly reduced neutrophil infiltration and inflammatory cytokine expression in the brain at 24 hours post TBI, which was accompanied by improved neurological dysfunction. Further investigation indicated that mGluR5 KO reduced the permeability of blood-brain barrier (BBB), the entrance for neutrophils to enter brain, and markedly decreased the mRNA levels of neutrophil-associated chemokines in brain tissue, including CXCL1, CXCL2, CCL2, CCL4 and CCL5. Using brain microvascular endothelial cells (BMECs), neutrophils and a BBB model in vitro, we confirmed the inhibitory effect of mGluR5 deficiency on neutrophil infiltration and demonstrated that blockade of protein kinase C (PKC) signaling was involved in it. These results provide insight into the role of mGluR5 in the regulation of inflammation in the acute phase of TBI, which may provide novel clues for TBI therapy.

The Emerging Role of GLP-1 Receptors in DNA Repair: Implications in Neurological Disorders

Glucagon-like peptide-1 (GLP-1) is originally found as a metabolic hormone (incretin) that is able to regulate blood-glucose levels via promoting synthesis and secretion of insulin. GLP-1 and many analogues are approved for treatment of type II diabetes. Accumulating results imply that GLP-1 performs multiple functions in various tissues and organs beyond regulation of blood-glucose. The neuroprotective function of GLP-1 has been extensively explored during the past two decades. Three of our previous studies have shown that apurinic/apyrimidinic endonuclease 1 (APE1) is the only protein of the base excision repair (BER) pathway able to be regulated by oxidative stress or exogenous stimulations in rat primary cortical neurons. In this article, we review the role of APE1 in neurodegenerative diseases and its relationship to neuroprotective mechanisms of the activated GLP-1 receptor (GLP-1R) in neurodegenerative disorders. The purpose of this article is to provide new insight, from the aspect of DNA damage and repair, for studying potential treatments in neurodegenerative diseases.

Cerebrovascular Protective Effect of Boldine Against Neural Apoptosis via Inhibition of Mitochondrial Bax Translocation and Cytochrome C Release

BACKGROUND In the present study, we explored the protective effect and mechanism of action of boldine (BOL) against neural apoptosis, which is a mediator of TBI. MATERIAL AND METHODS The effect of BOL on mitochondrial and cytosol proteins of extracted from cerebral cortical tissue of mice was evaluated. The grip test was used to assess the neurological deficit and brain water content of the subjects after administration of BOL to assess its effect on SOD, GSH, and MDA activity in brain ischemic tissues. To further confirm the effect of the BOL, the histopathological analysis and morphology of neurons were studied by Nissl staining. The effect of BOL against TBI-induced neural apoptosis by immuno-histochemistry and Western blotting assay were also studied. RESULTS BOL showed significant improvement against TBI in a dose-dependent manner. In the BOL-treated group, the apoptotic index was significantly reduced, but the level of caspase-3 was greatly diminished. Additionally, the level of the Bax in mitochondria (mit) and cytosol was elevated in the TBI-treated group as compared to the sham group. Further BOL at the test dose causes significant reduction in the level of mitochondrial MDA together with increase in SOD activity as compared to the TBI alone group. CONCLUSIONS BOL showed a cerebroprotective effect against TBI by attenuating the oxidative stress and the mitochondrial apoptotic pathway. It also inhibited mitochondrial Bax translocation and cytochrome c release.

Plasma creatine kinase B correlates with injury severity and symptoms in professional boxers

INTRODUCTION

Each year in the United States, approximately 1.7 million people sustain a traumatic brain injury (TBI). Of these TBI events, about 75 percent are characterized as being mild brain injuries. Immediately following TBI, a secondary brain damage persists for hours, days, and even months. Previously, detection of neuronal and glial biomarkers have proven to be useful to predict neurological outcomes. Here, we hypothesized that creatine kinase, brain (CKBB) is a sensitive biomarker for acute secondary brain injury in professional boxers.

METHODS

Blood (8cc) was collected from the boxing athletes (n=18) prior to and after competition (∼30min). The plasma levels of CKBB were measured using the Meso Scale Diagnostic (MSD) electrochemiluminescence (ECL) array-based multiplex format. Additional data such as number of blows to the head and symptom score (Rivermead Post Concussion Symptoms Questionnaire) were collected.

RESULTS

At approximately 30min after the competition, the plasma levels of CKBB were significantly elevated in concussed professional boxers and correlated with the number of blows to the head and symptom scores. Additionally, receiver operating curve (ROC) analysis yielded a 77.8% sensitivity and a specificity of 82.4% with an area under the curve (AUC) of 90% for CKBB as an identifier of secondary brain injury within this population.

CONCLUSION

This study describes the detection of CKBB as a brain biomarker to detect secondary brain injury in professional athletes that have experienced multiple high impact blows to the head. This acute biomarker may prove useful in monitoring secondary brain injury after injury.

Risk factors for myocardial dysfunction after traumatic brain injury: A one-year follow-up study

INTRODUCTION

Traumatic brain injury has been associated with an increased risk of myocardial dysfunction. Common abnormalities accompanying this pathology include electrocardiographic abnormalities, elevated creatine kinase levels, arrhythmias, and pathologic changes of the myocardium. The aim of this study was to determine if TBI patients have a higher risk of myocardial dysfunction than the general population and to identify the risk factors of myocardial dysfunction in TBI patients.

PATIENTS AND METHODS

The study sample was drawn from Taiwan's National Health Insurance Research Database of reimbursement claims, and comprised 26,860 patients who visited ambulatory care centers or were hospitalized with a diagnosis of TBI. The comparison group consisted of 134,300 randomly selected individuals. The stratified Fine and Gray regression was performed to evaluate independent risk factors for myocardial dysfunction in all patients and to identify risk factors in TBI patients.

RESULTS

During a 1-year follow-up period, 664 patients with TBI and 1494 controls developed myocardial dysfunction. TBI was independently associated with increased risk of myocardial dysfunction. Diabetes, hypertension, peptic ulcer disease, chronic liver disease and chronic renal disease were risk factors of myocardial dysfunction in TBI patients.

CONCLUSIONS

Individuals with TBI are at greater risk of developing myocardial dysfunction after adjustments for possible confounding factors. Early monitor should be initiated to decrease disability and dependence in patients with TBI.

ApoE Influences the Blood-Brain Barrier Through the NF-κB/MMP-9 Pathway After Traumatic Brain Injury

Apolipoprotein E (ApoE), encoded by the ApoE gene (APOE), influences the outcomes of traumatic brain injury (TBI), but the mechanism remains unclear. The present study aimed to investigate the effects of different ApoEs on the outcome of TBI and to explore the possible mechanisms. Controlled cortical impact (CCI) was performed on APOEε3 (E3) and APOEε4 (E4) transgenic mice, APOE-KO (KO) mice, and wild type (WT) mice to construct an in vivo TBI model. Neurological deficits, blood brain barrier (BBB) permeability and brain edema were detected at days 1, 3, and 7 after TBI. The results revealed no significant differences among the four groups at day 1 or day 3 after injury, but more severe deficits were found in E4 and KO mice than in E3 and WT mice. Furthermore, a significant loss of tight junction proteins was observed in E4 and KO mice compared with E3 and WT mice at day 7. Additionally, more expression and activation of NF-κB and MMP-9 were found in E4 mice compared with E3 mice. Different ApoEs had distinct effects on neuro-function and BBB integrity after TBI. ApoE3, but not E4, might inhibit the NF-κB/MMP-9 pathway to alleviate BBB disruption and improve TBI outcomes.

Understanding and managing the risk of "head impact" from in-hospital falls: A cross-sectional analysis of data from 166 public hospitals

BACKGROUND

Falls are a leading cause of preventable harm in the hospitalized elderly, and head impacts (HIs) can be a precursor to serious injury. The aim of this study was to examine if the risk of fall-related HI can be explained by incident characteristics.

METHODS

All reported falls across public hospital facilities in the state of Queensland, Australia, over a 2-year period were analyzed using univariate and multiple logistic regression.

RESULTS

In all, 650 instances of HI were reported across 24 218 falls. Falls due to fainting were associated with elevated HI odds (odds ratio [OR] = 2.00, 95% confidence interval [CI] = 1.30, 3.08). Similarly, falls while walking (OR = 1.48, 95% CI = 1.20, 1.81) and falls during certain time periods, namely, from 11:00 pm to midnight (OR = 1.79, 95% CI = 1.24, 2.59) and between 5:00 am and 6:00 am (OR = 1.50, 95% CI = 1.01, 2.22) were linked to increased HI odds. Falls among males were associated with lowered odds of HI (adjusted odds ratio [AOR] = 0.78, 95% CI = 0.64, 0.74).

CONCLUSIONS

Results confirm links between characteristics of inpatient falls and the likelihood of HI, and these data can assist risk managers to better target fall prevention strategies. Assisted mobility in high-risk patients and improved environmental lighting are advanced as foci for future research.

Effect of Memantine on Serum Levels of Neuron-Specific Enolase and on the Glasgow Coma Scale in Patients With Moderate Traumatic Brain Injury

Traumatic brain injury (TBI) is a major cause of disability and death globally. Despite significant progress in neuromonitoring and neuroprotection, pharmacological interventions have failed to generate favorable results. We examined the effect of memantine on serum levels of neuron-specific enolase (NSE), a marker of neuronal damage, and the Glasgow Coma Scale (GCS) in patients with moderate TBI. Patients were randomly assigned to the control group (who received standard TBI management) and the treatment group (who, alongside their standard management, received enteral memantine 30 mg twice daily for 7 days). Patients' clinical data, GCS, findings of head computed tomography, and serum NSE levels were collected during the study. Forty-one patients were randomized into the control and treatment groups, 19 and 22 patients respectively. Baseline characteristics and serum NSE levels were not significantly different between the 2 groups. The mean serum NSE levels for the memantine and the control groups on day 3 were 7.95 ± 2.86 and 12.33 ± 7.09 ng/mL, respectively (P = .05), and on day 7 were 5.03 ± 3.25 and 10.04 ± 5.72 ng/mL, respectively (P = .003). The mean GCS on day 3 was 12.3 ± 2.0 and 10.9 ± 1.9 in the memantine and control groups, respectively (P = .03). Serum NSE levels and GCS changes were negatively correlated (r = -0.368, P = .02). Patients with moderate TBI who received memantine had significantly reduced serum NSE levels by day 7 and marked improvement in their GCS scores on day 3 of the study.

The use and uptake of pupillometers in the Intensive Care Unit

BACKGROUND

Traumatic brain injury (TBI) is a significant public health issue. Assessing pupil reactivity is a crucial aspect of its management and the pupillometer has been shown to be a more objective tool compared to the standard penlight. Its use, however, is not widespread.

OBJECTIVE

To investigate the paucity in uptake, we examined the frequency of use of pupillometers (NeurOptics^®NPi-100™) amongst Intensive Care Unit (ICU) doctors and nurses, evaluated its user-friendliness and explored barriers to its use.

DESIGN

An online cross-sectional survey.

METHODS

Surveys were distributed five months after the introduction of pupillometers (in May 2015) to ICU doctors and nurses working in a quaternary referral centre providing state services for trauma. The survey included sections on: questions on demographics and experience, methods of conventional pupillary assessment in patients with TBI, experience of using the pupillometer, and questions on barriers to its use. Responses were collated as discrete variables and summarised using counts and proportions. Comparisons among proportions were undertaken using the chi-squared test and reported with 95% confidence intervals.

RESULTS

A total of 79 responses were recorded, predominantly 94.9% (n=75) from nursing staff. A total of 50 (63.3%) responders were using the pupillometers, with a mean frequency-of-use rating of 4.67 out of 10 and a mean user-friendliness rating of 6.28 out of 10. There was no association between frequency of use and user-friendliness (p=0.36). The main identified barriers to its use included a lack of education with regards to its use, a perceived lack of clinical significance, a lack of standardisation of documenting findings, and difficulties with access to disposable patient shields (Smartguards).

CONCLUSIONS

There was good adoption of the technology in the early phases of ICU implementation with user-friendliness rated favourably. In this paper we identify barriers to use and discuss possible solutions to increase clinical utility.

Primary decompressive craniectomy is associated with worse neurological outcome in patients with traumatic brain injury requiring acute surgery

BACKGROUND

The role of decompressive craniectomy in treating raised intracranial pressure (ICP) after traumatic brain injuries (TBI) is controversial. The aim of this study was to assess the differences in prognosis of patients initially treated by decompressive craniectomy, craniotomy, or conservatively.

METHODS

We conducted a single-center retrospective study on adult blunt TBI patients admitted to a neurosurgical intensive care unit during 2009-2012. Patients were divided into three groups based on their initial treatment - decompressive craniectomy, craniotomy, and conservative. Primary outcome was 6-month Glasgow Outcome Scale (GOS) dichotomized to favorable outcome (independent) and unfavorable outcome (dependent). The association between initial treatment and outcome was assessed using a logistic regression model adjusting for case-mix using known predictors of outcome.

RESULTS

Of the 822 included patients, 58 patients were in the craniectomy group, 401 patients in the craniotomy group, and 363 patients in the conservatively treated group. Overall, 6-month unfavorable outcome was 48%. After adjusting for case-mix, patients in the decompressive craniectomy group had a statistical significantly higher risk for poor neurological outcome compared to patients in the conservative group (OR 3.06, 95% CI 1.45-6.42) and craniotomy group (OR 3.61, 95% CI 1.74-7.51).

CONCLUSION

In conclusion, patients requiring primary decompressive craniectomy had a higher risk for poor neurological outcome compared to patients undergoing craniotomy or were conservatively treated. It is plausible that the poor prognosis is related to the TBI severity itself rather than the intervention. Further prospective randomized trials are required to establish the role of decompressive craniectomy in the treatment of patients with TBI.

Exploring the potential of natural and synthetic neuroprotective steroids against neurodegenerative disorders: A literature review

Neurodegeneration is a complex process, which leads to progressive brain damage due to loss of neurons. Despite exhaustive research, the cause of neuronal loss in various degenerative disorders is not entirely understood. Neuroprotective steroids constitute an important line of attack, which could play a major role against the common mechanisms associated with various neurodegenerative disorders like Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Natural endogenous steroids induce the neuroprotection by protecting the nerve cells from neuronal injury through multiple mechanisms, therefore the structural modifications of the endogenous steroids could be helpful in the generation of new therapeutically useful neuroprotective agents. The review article will keep the readers apprised of the detailed description of natural as well as synthetic neuroprotective steroids from the medicinal chemistry point of view, which would be helpful in drug discovery efforts aimed toward neurodegenerative diseases.

Pathological correlations between traumatic brain injury and chronic neurodegenerative diseases

Traumatic brain injury is among the most common causes of death and disability in youth and young adults. In addition to the acute risk of morbidity with moderate to severe injuries, traumatic brain injury is associated with a number of chronic neurological and neuropsychiatric sequelae including neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. However, despite the high incidence of traumatic brain injuries and the established clinical correlation with neurodegeneration, the causative factors linking these processes have not yet been fully elucidated. Apart from removal from activity, few, if any prophylactic treatments against post-traumatic brain injury neurodegeneration exist. Therefore, it is imperative to understand the pathophysiological mechanisms of traumatic brain injury and neurodegeneration in order to identify potential factors that initiate neurodegenerative processes. Oxidative stress, neuroinflammation, and glutamatergic excitotoxicity have previously been implicated in both secondary brain injury and neurodegeneration. In particular, reactive oxygen species appear to be key in mediating molecular insult in neuroinflammation and excitotoxicity. As such, it is likely that post injury oxidative stress is a key mechanism which links traumatic brain injury to increased risk of neurodegeneration. Consequently, reactive oxygen species and their subsequent byproducts may serve as novel fluid markers for identification and monitoring of cellular damage. Furthermore, these reactive species may further serve as a suitable therapeutic target to reduce the risk of post-injury neurodegeneration and provide long term quality of life improvements for those suffering from traumatic brain injury.

Hierarchically Enhanced Impact Resistance of Bioinspired Composites

An order of magnitude tougher than nacre, conch shells are known for being one of the toughest body armors in nature. However, the complexity of the conch shell architecture creates a barrier to emulating its cross-lamellar structure in synthetic materials. Here, a 3D biomimetic conch shell prototype is presented, which can replicate the crack arresting mechanisms embedded in the natural architecture. Through an integrated approach combining simulation, additive manufacturing, and drop tower testing, the function of hierarchy in conch shell's multiscale microarchitectures is explicated. The results show that adding the second level of cross-lamellar hierarchy can boost impact performance by 70% and 85% compared to a single-level hierarchy and the stiff constituent, respectively. The overarching mechanism responsible for the impact resistance of conch shell is the generation of pathways for crack deviation, which can be generalized to the design of future protective apparatus such as helmets and body armor.