Sex differences in traumatic brain injury: a multi-dimensional exploration in genes, hormones, cells, individuals, and society

Perturbations in risk/reward decision making and frontal cortical catecholamine regulation induced by mild traumatic brain injury

Mild traumatic brain injury (mTBI) disrupts cognitive processes that influence risk taking behavior. Little is known regarding the effects of repetitive mild injury (rmTBI) or whether these outcomes are sex specific. Risk/reward decision making is mediated by the prefrontal cortex (PFC), which is densely innervated by catecholaminergic fibers. Aberrant PFC catecholamine activity has been documented following TBI and may underlie TBI-induced risky behavior. The present study characterized the effects of rmTBI on risk/reward decision making behavior and catecholamine transmitter regulatory proteins within the PFC. Rats were exposed to sham, single (smTBI), or three closed-head controlled cortical impact (CH-CCI) injuries and assessed for injury-induced effects on risk/reward decision making using a probabilistic discounting task (PDT). In the first week post-final surgery, mTBI increased risky choice preference. By the fourth week, males exhibited increased latencies to make risky choices following rmTBI, demonstrating a delayed effect on processing speed. When levels of tyrosine hydroxylase (TH) and the norepinephrine reuptake transporter (NET) were measured within subregions of the PFC, females exhibited dramatic increases of TH levels within the orbitofrontal cortex (OFC) following smTBI. However, both males and females demonstrated reduced levels of OFC NET following rmTBI. These results indicate the OFC is susceptible to catecholamine instability after rmTBI and suggests that not all areas of the PFC contribute equally to TBI-induced imbalances. Overall, the CH-CCI model of rmTBI has revealed time-dependent and sex-specific changes in risk/reward decision making and catecholamine regulation following repetitive mild head injuries.

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.

Applicability and clinical utility of the German rivermead post-concussion symptoms questionnaire in proxies of children after traumatic brain injury: an instrument validation study

BACKGROUND

The German Rivermead Post-Concussion Symptoms Questionnaire (RPQ) can be used to assess post-concussion symptoms (PCS) after traumatic brain injury (TBI) in adults, adolescents, and children.

METHODS

In this study, we examined the psychometric properties of the German RPQ proxy version (N = 146) for children (8-12 years) after TBI at the item, total and scale score level. Construct validity was analyzed using rank correlations with the proxy-assessed Post-Concussion Symptoms Inventory (PCSI-P), the Patient Health Questionnaire 9 (PHQ-9), and the Generalized Anxiety Disorder Scale 7 (GAD-7). Furthermore, sensitivity testing was performed concerning subjects' sociodemographic and injury-related characteristics. Differential item functioning (DIF) was analyzed to assess the comparability of RPQ proxy ratings for children with those for adolescents.

RESULTS

Good internal consistency was demonstrated regarding Cronbach's α (0.81-0.90) and McDonald's ω (0.84-0.92). The factorial validity of a three-factor model was superior to the original one-factor model. Proxy ratings of the RPQ total and scale scores were strongly correlated with the PCSI-P (ϱ = 0.50-0.69), as well as moderately to strongly correlated with the PHQ-9 (ϱ = 0.49-0.65) and the GAD-7 (ϱ = 0.44-0.64). The DIF analysis revealed no relevant differences between the child and adolescent proxy versions.

CONCLUSIONS

The German RPQ proxy is a psychometrically reliable and valid instrument for assessing PCS in children after TBI. Therefore, RPQ self- and proxy-ratings can be used to assess PCS in childhood as well as along the lifespan of an individual after TBI.

The Association Between Gender and Clinical Outcomes in Patients With Moderate to Severe Traumatic Brain Injury: A Systematic Review and Meta-Analysis

INTRODUCTION

Traumatic brain injuries (TBIs) are a significant cause of morbidity and mortality in the United States. but have a disproportionate impact on patients based on gender. This systematic review and meta-analysis aim to compare gender differences in clinical outcomes between male and female adult trauma patients with moderate and severe TBI.

METHODS

Studies assessing gender differences in outcomes following TBIs on PubMed, Google Scholar, EMBASE, and ProQuest were searched. Meta-analysis was performed for outcomes including in-hospital mortality, hospital length of stay, intensive care unit length of stay, and Glasgow outcome scale (GOS) at 6 mo.

RESULTS

Eight studies were included for analysis with 26,408 female and 63,393 male patients. Meta-analysis demonstrated that males had a significantly lower risk of mortality than females (RR: 0.88; 95% CI 0.78, 0.99; P = 0.0001). Females had a shorter hospital length of stay (mean difference -1.4 d; 95% CI - 1.6 d, -1.2 d). No significant differences were identified in intensive care unit length of stay (mean difference -3.0 d; 95% CI -7.0 d, 1.1 d; P = 0.94) or GOS at 6 mo (mean difference 0.2 d; 95% CI -0.9 d, 1.4 d; P = 1).

CONCLUSIONS

Compared to male patients, female patients with moderate and severe TBI had a significantly higher in-hospital mortality risk. There were no significant differences in long-term outcomes between genders based on GOS at 6 mo. These findings warrant further investigation into the etiology of these gender disparities and their impact on additional clinical outcome measures.

Deplete and repeat: microglial CSF1R inhibition and traumatic brain injury

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

Utility of intracranial pressure monitoring in patients with traumatic brain injuries: a propensity score matching analysis of TQIP data

PURPOSE

Intracranial pressure monitoring (ICPM) is central to traumatic brain injury (TBI) management, but its utility is controversial.

METHODS

The 2016-2017 TQIP database was queried for isolated TBI. Patients with ICPM [(ICPM (+)] were propensity-score matched (PSM) to those without ICPM [ICPM (-)] and divided into three age groups by years (< 18, 18-54, ≥  55).

RESULTS

PSM yielded 2125 patients in each group. Patients aged < 18 years had a higher survival probability (p = 0.013) and decreased mortality (p = 0.016) in the ICPM (+) group. Complications were higher and LOS was longer in ICPM (+) patients aged 18-54 years and ≥ 55 years, but not in patients aged < 18 years.

CONCLUSIONS

ICPM (+) is associated with a survival benefit without an increase in complications in patents aged < 18 years. In patients aged ≥ 18 years, ICPM (+) is associated with more complications and longer LOS without a survival benefit.

Gender versus sex in predicting outcomes of traumatic brain injury: a cohort study utilizing large administrative databases

Understanding the factors associated with elevated risks and adverse consequences of traumatic brain injury (TBI) is an integral part of developing preventive measures for TBI. Brain injury outcomes differ based on one's sex (biological characteristics) and gender (social characteristics reflecting norms and relationships), however, whether it is sex or gender that drives differences in early (30-day) mortality and discharge location post-TBI is not well understood. In the absence of a gender variable in existing data, we developed a method for "measuring gender" in 276,812 residents of Ontario, Canada who entered the emergency department and acute care hospitals with a TBI diagnostic code between April 1st, 2002, and March 31st, 2020. We applied logistic regression to analyse differences in diagnostic codes between the sexes and to derive a gender score that reflected social dimensions. We used the derived gender score along with a sex variable to demonstrate how it can be used to separate the relationship between sex, gender and TBI outcomes after severe TBI. Sex had a significant effect on early mortality after severe TBI with a rate ratio (95% confidence interval (CI)) of 1.54 (1.24-1.91). Gender had a more significant effect than sex on discharge location. A person expressing more "woman-like" characteristics had lower odds of being discharged to rehabilitation versus home with odds ratio (95% CI) of 0.54 (0.32-0.88). The method we propose offers an opportunity to measure a gender effect independently of sex on TBI outcomes.

An updated Barnes maze protocol for assessing the outcome of controlled cortical impact mouse models of traumatic brain injury

BACKGROUND

The Barnes Maze (BM) is a common method of testing cognitive deficits in rodents. Adapting BM protocols for specific neurological disorders could potentially aid in more effective testing, reduce research time, and help decrease variability between studies.

NEW METHOD

We tested differences an updated, shortened BM consisting of 6 days, 3 trials per day, only covering the equivalent of the spatial acquisition week BM protocol and a probe trial day consisting of one trial (7 total days).

RESULTS

Kaplan-Meier plots of escape percentage as a function of total latency showed a significant difference between control and CCI mice in the updated protocol on days 3 through 6. Additionally, probe trial data showed significant differences in primary latency, primary errors, and returns to goal.

COMPARISON WITH EXISTING METHODS

We tested differences between a traditional 5 days per week, 2 trials per day, spatial acquisition and reversal weeks BM protocol (12 total days with probe trials) with an updated 6-day BM protocol (7 total days with probe trial). In the probe trial, the updated protocol control mice showed an over 5-fold decrease in primary latency and primary errors and a 4.6-fold increase in returns to goal compared to the traditional protocol. Additionally, mice in both protocols performed similarly on a trial-by-trial basis suggesting that the changes made for the updated protocol increased learning and memory and was not simply an easier task.

CONCLUSION

The updated BM protocol showed an improved ability to distinguish between control and CCI mice and promoted improved and more consistent learning for both the control and CCI groups.

An educational intervention to promote a culture of gender equity among persons with traumatic brain injury and caregivers: A pilot study

Background

Traumatic brain injury (TBI) outcomes are dependent on patients' biological sex (e.g., hormone levels) and sociocultural gender (e.g., norms, responsibilities). Informal caregivers additionally experience disruptions to identity and roles post-TBI. However, information on this topic remains largely unavailable to patients and caregivers.

Purpose

This study aimed to determine the effectiveness of a one-time educational intervention on sex and gender influences in TBI for patients and informal caregivers.

Materials and methods

We conducted a pilot pre-test/post-test randomized control-group design study. Groups (i.e., passive, active and control) consisted a total of 16 persons with TBI and caregivers (75% persons with TBI, 63% women). Individual and group learning gains, and group-average normalized gain, were computed for three learning domains: knowledge, attitude, and skill. An intervention with an average normalized gain of ≥30% was considered effective. Educational intervention evaluation and qualitative comments post-participation were summarized.

Results

The passive group demonstrated the highest average normalized gain across the three learning domains, including 100% for knowledge, 40% and 61% for attitude, and 37% for skill. The remaining groups did not reach an average normalized gain of ≥30%, except for the attitude domain of the control group (33% and 32%). Two key categories were identified qualitatively: (1) gendered self-expectations post-injury and (2) implications of gender stereotypes in rehabilitation, including the need for rehabilitation treatment to look beyond sex and gender. The post-participation educational session evaluation conveyed high appraisal of content, organization, and usability of the intervention.

Conclusion

A one-time passive educational intervention on sex and gender in TBI may improve knowledge, attitude, and skill on the topic of sex and gender among adults with TBI and caregivers. Obtaining knowledge and skill on sex and gender effects in TBI can potentially help persons with TBI and caregivers adapt to changes in roles and behaviours post-injury.

Gender versus sex in predicting outcomes of traumatic brain injury: A cohort study utilizing large administrative databases

Understanding the factors associated with elevated risks and adverse consequences of traumatic brain injury (TBI) is an integral part of developing preventive measures for TBI. Brain injury outcomes differ based on one's sex (biological characteristics) and gender (social characteristics reflecting norms and relationships), however, whether it is sex or gender that drives differences in early (30-day) mortality and discharge location post-TBI event are unknown. In the absence of gender variable in existing data, we developed a method for "measuring gender" in 276,812 residents of Ontario, Canada who entered the emergency department and acute care hospitals with a TBI diagnostic code between April 1st, 2002 and March 31st, 2020. We analysed differences in diagnostic codes between the sexes to derive gender score that reflected social dimensions. Sex had a significant effect on early mortality after severe TBI with a rate ratio (95% confidence interval (CI)) of 1.54 (1.24-1.91). Gender had a more significant effect than sex on discharge location. A person expressing more female-like characteristics have lower odds of being discharged to rehabilitation versus home with odds ratio (95% CI) of 0.54 (0.32-0.88). The method we propose offers an opportunity to measure gender effect independently of sex on TBI outcomes.

Drosophila melanogaster as a model to study age and sex differences in brain injury and neurodegeneration after mild head trauma

Repetitive physical insults to the head, including those that elicit mild traumatic brain injury (mTBI), are a known risk factor for a variety of neurodegenerative conditions including Alzheimer's disease (AD), Parkinson's disease (PD), and chronic traumatic encephalopathy (CTE). Although most individuals who sustain mTBI typically achieve a seemingly full recovery within a few weeks, a subset experience delayed-onset symptoms later in life. As most mTBI research has focused on the acute phase of injury, there is an incomplete understanding of mechanisms related to the late-life emergence of neurodegeneration after early exposure to mild head trauma. The recent adoption of Drosophila-based brain injury models provides several unique advantages over existing preclinical animal models, including a tractable framework amenable to high-throughput assays and short relative lifespan conducive to lifelong mechanistic investigation. The use of flies also provides an opportunity to investigate important risk factors associated with neurodegenerative conditions, specifically age and sex. In this review, we survey current literature that examines age and sex as contributing factors to head trauma-mediated neurodegeneration in humans and preclinical models, including mammalian and Drosophila models. We discuss similarities and disparities between human and fly in aging, sex differences, and pathophysiology. Finally, we highlight Drosophila as an effective tool for investigating mechanisms underlying head trauma-induced neurodegeneration and for identifying therapeutic targets for treatment and recovery.

Propranolol Reduces p-tau Accumulation and Improves Behavior Outcomes in a Polytrauma Murine Model

INTRODUCTION

Traumatic brain injury (TBI) can lead to neurocognitive decline, in part due to phosphorylated tau (p-tau). Whether p-tau accumulation worsens in the setting of polytrauma remains unknown. Propranolol has shown clinical benefit in head injuries; however, the underlying mechanism is also unknown. We hypothesize that hemorrhagic shock would worsen p-tau accumulation but that propranolol would improve functional outcomes on behavioral studies.

METHODS

A murine polytrauma model was developed to examine the accumulation of p-tau and whether it can be mitigated by early administration of propranolol. TBI was induced using a weight-drop model and hemorrhagic shock was achieved via controlled hemorrhage for 1 h. Mice were given intraperitoneal propranolol 4 mg/kg or saline control. The animals underwent behavioral testing at 30 d postinjury and were sacrificed for cerebral histological analysis. These studies were completed in male and female mice.

RESULTS

TBI alone led to increased p-tau generation compared to sham on both immunohistochemistry and immunofluorescence (P < 0.05). The addition of hemorrhage led to greater accumulation of p-tau in the hippocampus (P < 0.007). In male mice, p-tau accumulation decreased with propranolol administration for both polytrauma and TBI alone (P < 0.0001). Male mice treated with propranolol also outperformed saline-control mice on the hippocampal-dependent behavioral assessment (P = 0.0013). These results were not replicated in female mice; the addition of hemorrhage did not increase p-tau accumulation and propranolol did not demonstrate a therapeutic effect.

CONCLUSIONS

Polytrauma including TBI generates high levels of hippocampal p-tau, but propranolol may help prevent this accumulation to improve both neuropathological and functional outcomes in males.

Gender Differences in Executive Functions of Patients Operated for Mild to Moderate Epidural Hematoma

Background Impairment in neurocognitive functions are commonly followed by Epidural hematoma (EDH) . This cross-sectional study was aimed to study gender differences in neurocognitive functions in mild to moderate epidural hematoma patients (43 male and 19 female patients) post-surgery using standardized assessment tools of comprehensive neurocognitive function attention, speed, working memory, fluency, set-shifting, perseveration, planning and response inhibition.

Methods Descriptive statistics, i.e., mean and standard deviation (SD) values were computed, and a t-test was applied for further exploration.

Results The analysis of results shows that on the test of working memory, female group scored better as significant differences were found on N-Back (2 Back versions) and digit span-backward. On the verbal fluency test (COWA), significant difference was found as females scored higher than the male group on total responses. However, the male group was higher in total time and error than the female group on the test of sustained attention and divided attention.

Conclusion This study shows interesting results in terms of gender differences in executive function of patients operated for mild to moderate epidural hematoma. These findings have significant clinical and implications for planning intervention. The neuropsychological rehabilitation of patients operated for mild to moderate epidural hematoma has a crucial role in enhancing their recovery and overall functioning. Inputs about gender differences in neuro psychological functioning of these patients would help in decision making regarding neuropsychological rehabilitation incorporating the gender related differences too in their intervention plan.

The outcome of severely injured patients following traumatic brain injury is affected by gender—A retrospective, multicenter, matched-pair analysis utilizing data of the TraumaRegister DGU®

Introduction

Traumatic brain injury (TBI) causes a major health-concern globally. Gender-dependent differences in mortality outcome after TBI have been controversially discussed.

Materials and methods

We conducted a retrospective, multicenter, matched-pair analysis using data collected by the TraumaRegister DGU® of the German Trauma Society between 2009 and 2020. All patients after severe trauma with the leading injury of TBI (AIS ≥ 3), above 18 years of age were included. Thereby, 42,034 cases were identified. We used 12 different matching criteria to ensure highly accurate matching and were able to match 11,738 pairs of one female and one male patient.

Results

Average age at injury was 67.5 ± 19.6 years in women and 66.7 ± 19.1 years in men. Mean Injury Severity Score (ISS) was 21.3 ± 8.1 in women and 21.6 ± 8.2 in men. While women were more likely to die within the first week after trauma, the mortality was significantly higher in men overall (30.8 vs. 29.2%, p &lt; 0.002). Women were less likely to suffer from multi organ failure (MOF) (27.5 vs. 33.0%) or sepsis (4.5 vs. 7.1%). When comparing younger (≤ 45-years) and older (&gt; 45 years) patients, overall mortality was lower in men (13.1% men vs. 13.4% women) in the younger age group, but in the older group mortality was lower in women (33.8% men vs. 31.8% women).

Discussion

Gender-specific differences in the clinical outcome of severely injured patients with leading TBI could be detected. While women are overall characterized by an advantage in survival, this feature is not equally reproducible in premenopausal women. Therefore, the exact pathophysiological reasons for the described survival advantages of women will have to be explored in further prospective clinical studies.

Sexual dimorphism in immune cell responses following stroke

Recent bodies of work in regard to stroke have revealed significant sex differences in terms of risk and outcome. While differences in sex hormones have been the focus of earlier research, the reasons for these differences are much more complex and require further identification. This review covers differences in sex related immune responses with a focus on differences in immune cell composition and function. While females are more susceptible to immune related diseases, they seem to have better outcomes from stroke at the experimental level with reduced pro-inflammatory responses. However, at the clinical level, the picture is much more complex with worse neurological outcomes from stroke. While the use of exogenous sex steroids can replicate some of these findings, it is apparent that many other factors are involved in the modulation of immune responses. As a result, more research is needed to better understand these differences and identify appropriate interventions and risk modification.

Gender Discrepancy in Patients with Traumatic Brain Injury: A Retrospective Study from a Level 1 Trauma Center

Objectives. The objective of this study is to explore the gender discrepancy in patients with traumatic brain injury (TBI). Methods. A retrospective analysis of Qatar Trauma Registry (QTR) was conducted among patients (age ≥14y) who were hospitalized with TBI. Data were collected and analyzed based on the gender and age. Results. Over 5 years (2014-2019), 9, 309 trauma patients (90% males and 10% females) were admitted to the trauma center. Of these, 1, 620 (17.4%) patients were hospitalized with TBI (94% males and 6% females). Motor vehicle crash was the main mechanism of injury (MOI) in females, and fall from height was predominant among males. Subdural hematoma (SDH) was the more frequent type of TBI in both genders, but it was more prevalent in male patients ≥55 years. Injury severity score, Glasgow coma scale, and head abbreviated injury score were comparable between males and females. The length of stay in the ICU and hospital and mortality were similar in both genders. However, mortality was higher among males ≥55 years when compared to 14-54 years within the same gender (21% vs. 12%, $p=0.002$ ). The crude and adjusted odds ratio did not show that gender is a significant predictor of mortality among TBI patients. Conclusions. Although the incidence and MOI of TBI show significant differences between male and female patients, the severity and outcomes are comparable.

Electroacupuncture improves TBI dysfunction by targeting HDAC overexpression and BDNF-associated Akt/GSK-3β signaling

Background

Acupuncture or electroacupuncture (EA) appears to be a potential treatment in acute clinical traumatic brain injury (TBI); however, it remains uncertain whether acupuncture affects post-TBI histone deacetylase (HDAC) expression or impacts other biochemical/neurobiological events.

Materials and methods

We used behavioral testing, Western blot, and immunohistochemistry analysis to evaluate the cellular and molecular effects of EA at LI4 and LI11 in both weight drop-impact acceleration (WD)- and controlled cortical impact (CCI)-induced TBI models.

Results

Both WD- and CCI-induced TBI caused behavioral dysfunction, increased cortical levels of HDAC1 and HDAC3 isoforms, activated microglia and astrocytes, and decreased cortical levels of BDNF as well as its downstream mediators phosphorylated-Akt and phosphorylated-GSK-3β. Application of EA reversed motor, sensorimotor, and learning/memory deficits. EA also restored overexpression of HDAC1 and HDAC3, and recovered downregulation of BDNF-associated signaling in the cortex of TBI mice.

Conclusion

The results strongly suggest that acupuncture has multiple benefits against TBI-associated adverse behavioral and biochemical effects and that the underlying mechanisms are likely mediated by targeting HDAC overexpression and aberrant BDNF-associated Akt/GSK-3 signaling.

The change of serum and CSF BDNF level as a prognosis predictor in traumatic brain injury cases: A systematic review

Background:

Mortality predictions following traumatic brain injury (TBI) may be improved by including genetic risk in addition to traditional prognostic variables. One promising target is the gene coding for brain-derived neurotrophic factor (BDNF), a ubiquitous neurotrophin important for neuronal survival and neurogenesis.

Methods:

A total of seven publications pertaining to BDNF in the study of traumatic head injury were included and reviewed. The majority of patients were male, that is, 483 (83.85%) patients, compared to 93 (16.15%) female patients. The median length of follow-up was 6 months (3 days–12 months). Measurement of the patient’s initial condition was carried out by measuring the initial GCS of the patient at the time of admission across the five studies being 6.5. The median CSF BDNF levels in the unfavorable group being 0.2365 (0.19–0.3119) ng/ml, from favorable group which was 0.20585 (0.17–0.5526) ng/ml. The median serum BDNF level in the unfavorable group being 3.9058 (0.6142–13.0) ng/ml, from favorable group which was 4.3 (0.6174–23.3) ng/ml.

Results:

Six studies reported on the sex distribution of patients, the majority of patients were male, that is, 483 (83.85%) patients, compared to 93 (16.15%) female patients. Six studies reported the number of patients per outcome group. The comparison of the number of patients in the two groups was quite balanced with the number of patients in the good group as many as 269 patients (55.5%) and the number of patients in the unfavorable group as many as 216 patients (44.5%). Measurement of the patient’s initial condition was carried out by measuring the patient’s initial GCS at the time of admission. It was reported in five studies, with the overall mean baseline GCS across five studies being 6.5 (3.2–8.8). Measurement of patient outcome was carried out by several methods, two studies used Glasgow Outcome Scale, Glasgow Outcome Scale Extended was used in two studies, and five studies used survival as a patient outcome measure. The patient’s BDNF level was measured in CSF and/or serum. A total of four studies measuring BDNF CSF levels and serum BDNF levels. Measurement of BDNF levels in TBI patients conducted on patients in seven literatures showed that there were differences in the trend of BDNF levels from CSF sources and serum sources. Measurement of CSF BDNF levels CSF BDNF levels was reported in two of the seven literatures, with the median CSF BDNF level in the unfavorable group being 0.2365 (0.19–0.3119) ng/ml. CSF BDNF levels were higher than the median in the preferred group, which was 0.20585 (0.17–0.5526) ng/ml. The results of the analysis from three other literatures stated that there was a tendency for lower CSF BDNF levels in the preferred group. Serum BDNF levels were reported in two of the seven literatures, with the median serum BDNF level in the unfavorable group being 3.9058 (0.6142–13.0) ng/ml. This serum BDNF level was lower than the median in the preferred group, which was 4.3 (0.6174–23.3) ng/ml. The results of the analysis of four literatures reporting serum BDNF stated that there was a tendency for lower serum BDNF levels in the poor group. A risk assessment of bias for each study was performed using ROBINS-I because all included studies were non-RCT studies. Overall the results of the risk of bias analysis were good, with the greatest risk of confounding bias and outcome bias.

Conclusion:

Serum BDNF levels were found to be lower in the unfavorable group than in the favorable group. This is associated with an increase in autonomic function as well as a breakdown of the blood–brain barrier which causes a decrease in serum BDNF levels. Conversely, CSF BDNF levels were found to be higher in the unfavorable group than in the favorable group. This is associated with an increase in the breakdown of the blood–brain barrier which facilitates the transfer of serum BDNF to the brain, leading to an increase in CSF BDNF levels.

Gender Influences Virtual Reality-Based Recovery of Cognitive Functions in Patients with Traumatic Brain Injury: A Secondary Analysis of a Randomized Clinical Trial

The rehabilitation of cognitive deficits in individuals with traumatic brain injury is essential for promoting patients’ recovery and autonomy. Virtual reality (VR) training is a powerful tool for reaching this target, although the effectiveness of this intervention could be interfered with by several factors. In this study, we evaluated if demographical and clinical variables could be related to the recovery of cognitive function in TBI patients after a well-validated VR training. One hundred patients with TBI were enrolled in this study and equally randomized into the Traditional Cognitive Rehabilitation Group (TCRG: n = 50) or Virtual Reality Training Group (VRTG: n = 50). The VRTG underwent a VRT with BTs-N, whereas the TCRG received standard cognitive treatment. All the patients were evaluated by a complete neuropsychological battery before (T0) and after the end of the training (T1). We found that the VR-related improvement in mood, as well as cognitive flexibility, and selective attention were influenced by gender. Indeed, females who underwent VR training were those showing better cognitive recovery. This study highlights the importance of evaluating gender effects in planning cognitive rehabilitation programs. The inclusion of different repetitions and modalities of VR training should be considered for TBI male patients.

The Emergence of Model Systems to Investigate the Link Between Traumatic Brain Injury and Alzheimer’s Disease

Numerous epidemiological studies have demonstrated that individuals who have sustained a traumatic brain injury (TBI) have an elevated risk for developing Alzheimer’s disease and Alzheimer’s-related dementias (AD/ADRD). Despite these connections, the underlying mechanisms by which TBI induces AD-related pathology, neuronal dysfunction, and cognitive decline have yet to be elucidated. In this review, we will discuss the various in vivo and in vitro models that are being employed to provide more definite mechanistic relationships between TBI-induced mechanical injury and AD-related phenotypes. In particular, we will highlight the strengths and weaknesses of each of these model systems as it relates to advancing the understanding of the mechanisms that lead to TBI-induced AD onset and progression as well as providing platforms to evaluate potential therapies. Finally, we will discuss how emerging methods including the use of human induced pluripotent stem cell (hiPSC)-derived cultures and genome engineering technologies can be employed to generate better models of TBI-induced AD.

Repeated mild traumatic brain injury impairs fracture healing in male mice

Objectives

The goal of this study was to evaluate the long-term impact of repeated (r) mild traumatic brain injury (mTBI) on the healing of fractures in a mouse model. Ten week-old male mice were subjected to r-mTBI once per day for 4 days followed by closed femoral fracture using a three-point bending technique, 1 week post impact and fracture healing phenotype evaluated at 20 weeks of age.

Results

Micro-CT analysis of the fracture callus region at nine weeks post fracture revealed reduced bone volume (30%, p < 0.05) in the r-mTBI fracture group compared to the control-fracture group. The connectivity density of the fracture callus bone was reduced by 40% (p < 0.01) in the r-mTBI fracture group. Finite element analysis of the fracture callus region showed reduced failure load (p = 0.08) in the r-mTBI group compared to control group. There was no residual cartilage in the fracture callus region of either the r-mTBI or control fracture group. The reduced fracture callus bone volume and mechanical strength of fracture callus in r-mTBI mice 9 weeks post fracture are consistent with negative effects of r-mTBI on fracture healing over a long-term resulting in decreased mechanical strength of the fracture callus.

Salivary Biomarkers as Indicators of TBI Diagnosis and Prognosis: A Systematic Review

BACKGROUND AND OBJECTIVE

Traumatic brain injuries are physical injuries to the head that result in disruptions to normal brain function. Diagnostic tools such as computed tomography scans have commonly been used to detect traumatic brain injuries but are costly and not ubiquitously available. Recent research on diagnostic alternatives has focused on using salivary biomarkers, but there is no consensus on the utility of these methods.  The objective of this manuscript is to address the gap in the literature pertaining to the effectiveness of salivary biomarkers for TBI diagnosis and prognosis.

METHODS

A systematic review was conducted between November 2020 and October 2021 using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Six databases were searched using the terms "traumatic brain injury," "TBI," "saliva," and "biomarkers." Literature published prior to 2010 was excluded, and two authors reviewed each full-text article to ensure its relevance.

RESULTS

A total of 18 articles were included in this review, with nine articles on salivary microRNA, three on salivary hormones, three on salivary extracellular vesicles, and three on salivary proteins.

CONCLUSIONS

Studies reported changes in salivary biomarkers after traumatic brain injuries and indicated a possible link between salivary biomarker expression and traumatic brain injury severity. However, it is unclear the degree to which salivary biomarkers accurately predict traumatic brain injury diagnosis and prognosis; some studies reported significant associations while others reported weaker associations. More research into the robustness of salivary biomarkers is needed to fully elucidate their utility for the traumatic brain injury population.

The relationship between HbA1C levels and clinical outcome in patients with traumatic train injury: A prospective study

Introduction/Aim: Recently, hemoglobin A1c (HbA1c) has been suggested as a predictor of mortality and poor clinical outcome in patients with trauma. The aim of this study was to evaluate the relationship between HbA1c values and clinical outcome in patients with traumatic brain injury (TBI). Methods: In a cross-sectional study, a total of 133 TBI patients referred to the emergency department of Imam Khomeini Hospital in Sari, Mazandaran, Iran were evaluated. After transferring the patients to the neurosurgery ward, their HbA1c, fasting blood glucose (FBG) and postprandial glucose (PPG) were measured. Also, patients' Glasgow Coma Scale (GCS) score was recorded at the time of admission, 24 hours after admission and at the time of discharge from the hospital. Results: The mean of GCS score of patients at the time of admission, 24 hours after admission, and at the time of discharge were 9.02 (2.09), 10.07 (2.16), and 12.98 (1.82), respectively. The mean GCS score of patients with HbA1c < 5.7% was significantly lower than of patients with HbA1c = 5.7 - 6.5% at the time of admission (p < 0.05). At 24 hours after admission, the mean GCS score of patients with HbA1c < 5.7% was significantly lower than in other groups (p < 0.05). However, at the time of discharge, the mean GCS score of patients with HbA1c > 6.5% was significantly lower than in patients with HbA1c = 5.7 - 6.5% (p < 0.05). Over time, the mean of GCS scores in all patients significantly increased (p < 0.001). Conclusion: According to the results of this study it seems that HbA1c measurements cannot provide clear information about the clinical outcome of patients with TBI.

Literature Review of Sex Differences in mTBI

INTRODUCTION

Traumatic brain injury (TBI) remains a significant source of morbidity worldwide and is of particular concern for the military. Scientific literature examining sex differences in TBI is highly contradictory with some reporting better outcomes in men, others reporting better outcomes in women, and others reporting mixed results or no difference. While the exact cause is currently debated, the existence of such differences has important implications for surveillance techniques, treatment options, and management of long-term consequences. As the number of women within the U.S. military ranks increases and with the opening of combat roles to women in 2013, increased awareness of probable sex differences regarding TBI responses will enable better standard of care.

MATERIALS AND METHODS

Using the PubMed database, a keyword search using gender, "sex factors", "sex dependent", "gender disparity", TBI, "traumatic brain injury", mTBI (mild TBI), and "cranial trauma" was used to identify articles of interest. Results were filtered for written in the last 5 years, English, and free full text. References of relevant articles were cross-checked for additional publications. Articles familiar to the authors were also included.

RESULTS

We review literature that includes analysis of age as an interaction in TBI, hypothesized mechanisms to explain variations in outcomes between men and women, and the need for inclusion of sex as a criterion in future studies.

CONCLUSIONS

Emerging studies underscore the complexity of interpreting sex differences in TBI. The long-held belief that women have a neuroprotective advantage compared to men based on higher levels of sex hormones is being re-evaluated. Past conclusions have relied extensively on clinical studies that include a disproportionate number of men or do not stratify results based on sex. While sex hormones may be neuroprotective, underlying mechanisms are far from clarified. Future TBI studies must include women and gonadal hormone levels should be measured to address potential variables. Given the significant number of TBIs within the military, an improved understanding of TBI pathophysiology and outcomes is important considerations for mission success and servicemember longevity.

Recommencement of anticoagulation/antiplatelet therapy following non-operative management of a Chronic Subdural Hematoma - Is there an optimal time frame?

Background

There is no consensus among clinicians regarding recommencement of antithrombotic agents following conservative management of a Chronic Subdural Hematoma (cSDH). Thus, the primary objective of this study was to determine the most commonly recommended interval and whether the data reveal a general consensus that should be adopted.

Methods

A retrospective analysis of Salford Royal Foundation Trust's Neurosurgical referral database for patients referred with a cSDH between March 2017 and March 2020 was carried out. Patients were sorted by whether they were on blood-thinning medications.

Results

Over the 3-year period, there were a total of 1220 referral and 1099 patients. 502 (41.14%) of these referrals and 479 (43.59%) patients were on one more blood thinning agent. Of these patients 221 (46.13%) conservative management, there was a clear male predominance (M: F ≈ 2.5:1) in this cohort. 2 weeks was the most commonly advised time-frame (n = 76, 36.36%) to withhold. Of the 234 referrals, there were 13 (5.88%) re-referrals in total. Crucially, there was no significant difference in reaccumulation rates between patients asked to withhold their blood thinners for 2 weeks versus those asked to stop for longer than 2 weeks (P = 0.57).

Conclusion

For the majority of bleeds, there is no clear benefit from asking patients to withhold their anticoagulant/antiplatelet for longer than 2 weeks. In cases, where it is deemed appropriate to stop for longer than 2 weeks, clear instructions should be provided and documented along with reasons behind the decision.

Short review: The impact of sex on neuroimmune and cognitive outcomes after traumatic brain injury

Traumatic brain injury (TBI) is an ever growing health concern, with cases increasing in both the US and the world at large. With the improvement of emergency medicine in recent decades, survival from TBI has become more common place, and thus individuals are coping with long-term deleterious outcomes from trauma as a result. Such outcomes include altered cognitive (memory loss/executive function), social (isolation tendencies), and behavioral (risk-taking behavior/anxiety) function. Researchers use preclinical rodent models to investigate cellular and molecular underpinnings of adverse TBI outcomes. One leading mechanism of long-term cognitive changes include alterations of immune function in the brain (termed 'neuroimmune'). Studies have found that TBI can induce chronic maladaptive neuroimmune responses, which can in turn propagate long-term neurological deficits. Unfortunately, most of the molecular understanding of TBI-induced neuroimmune outcomes is derived from studies performed solely in males. This is especially problematic as sex-dimorphic neuroimmune changes have been identified in healthy individuals. If and how these basal neuroimmune differences influence TBI related outcomes is the focus of this short review. Importantly, understanding these differences could allow for improved therapeutic development for treating the long-term effects of TBI.

Shape effect of cerium oxide nanoparticles on mild traumatic brain injury

The catalytic performance and therapeutic effect of nanoparticles varies with shape. Here, we investigated and compared the therapeutic outcomes of ceria nanospheres (Ceria NSs) and ceria nanorods (Ceria NRs) in an in vivo study of mild traumatic brain injury (mTBI). In vivo TBI was induced in a mouse model of open head injury using a stereotaxic impactor. Outcomes including cytoprotective effects, cognitive function, and cerebral edema were investigated after retro-orbital injection of 11.6 mM of ceria nanoparticles. Ceria nanoparticles significantly reduced fluoro-jade B (FJB)-positive cells and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive cells, and restored mRNA levels of superoxide dismutase 1 (SOD1) and SOD2. They also decreased the cyclooxygenase-2 (COX-2) expression compared with the untreated control group. Comparing the two nanomaterials, Ceria NRs showed less stable and high-energy (100) and (110) planes, which increased the number of active sites. The Ce3+/Ce4+ molar ratio of Ceria NRs (0.40) was greater than that of Ceria NSs (0.27). Ceria NRs (0.059 ± 0.021) appeared to exhibit better anti-inflammatory effect than Ceria NSs (0.133 ± 0.024), but the effect was statistically insignificant (p = 0.190). Ceria nanoparticles also improved cognitive impairment following mTBI compared with the control group, but the effect did not differ significantly according to the nanoshape. However, Ceria NRs (70.1 ± 0.5%) significantly decreased brain water content compared with Ceria NSs (73.7 ± 0.4%; p = 0.0015), indicating a more effective reduction in brain edema (p = 0.0015). Compared with Ceria NSs, the Ceria NRs are more effective in alleviating cerebral edema following in vivo mTBI.

Demographic Characteristics, Motivation and Perception of Change as Determinants of Memory Compensation Self-Reports After Acquired Brain Injury

INTRODUCTION

Individuals with brain injuries experience cognitive and emotional changes that have long-lasting impacts on everyday life. In the context of rehabilitation, surveys have stressed the importance of compensating for memory disturbances to ease the impact of disorders on day-to-day autonomy. Despite extensive research on the nature of neurocognitive impairments following brain injury, few studies have looked at patients' perceptions of these day-to-day compensations. This study examines these perceptions; in particular, what brain-injured people believe they do to compensate for memory deficiencies in everyday life. It also investigates the determinants of reported compensation strategies (age, gender, perceived stress, change awareness and motivation to succeed).

METHODS

Eighty patients and 80 controls completed the French Memory Compensation Questionnaire, a self-report measure of everyday memory compensation. Five forms of compensation were investigated: External and Internal strategies, Reliance on social help, and investments in Time and Effort, along with two general factors: the degree of importance attached to Success (motivation) and perceptions of Change. Participants also completed measures of demographic and emotional aspects that may affect everyday compensation perceptions.

RESULTS

The brain-injured group reported significantly more frequent use of memory compensation strategies than controls, with the exception of External aids. Large effects were observed for Reliance and Effort. Demographic, motivation and perception of change determinants were found to have different effects depending on the compensation strategy, and mediated the direct effect of brain injury on reported compensation.

CONCLUSION

Clinical and rehabilitation neuropsychologists often seek to have a better sense of how their patients perceive their compensatory behaviors. In practice, such an understanding is needed to help select appropriate methods and improve the long-term impact of rehabilitation programs: memory rehabilitation will fail if neuropsychologists do not deal, first and foremost, with the emotional and metacognitive issues surrounding traumatic brain injury (TBI), rather than focusing on cognitive efficiency.

Emerging COVID-19 Neurological Manifestations: Present Outlook and Potential Neurological Challenges in COVID-19 Pandemic

The unremitting coronavirus disease 2019 (COVID-19) pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) marked a year-long phase of public health adversaries and has severely compromised healthcare globally. Early evidence of COVID-19 noted its impact on the pulmonary and cardiovascular functions, while multiple studies in recent time shed light on its substantial neurological complications, though a comprehensive understanding of the cause(s), the mechanism(s), and their neuropathological outcomes is scarce. In the present review, we conferred evidence of neurological complications in COVID-19 patients and shed light on the SARS-CoV-2 infection routes including the hematogenous, direct/neuronal, lymphatic tissue or cerebrospinal fluid, or infiltration through infected immune cells, while the underlying mechanism of SARS-CoV-2 invasion to the central nervous system (CNS) was also discussed. In an up-to-date manner, we further reviewed the impact of COVID-19 in developing diverse neurologic manifestations associated with CNS, peripheral nervous system (PNS), skeletal muscle, and also pre-existing neurological diseases, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, epilepsy, and myasthenia gravis. Furthermore, we discussed the involvement of key factors including age, sex, comorbidity, and disease severity in exacerbating the neurologic manifestations in COVID-19 patients. An outlook of present therapeutic strategies and state of existing challenges in COVID-19 management was also accessed. Conclusively, the present report provides a comprehensive review of COVID-19-related neurological complications and emphasizes the need for their early clinical management in the ongoing COVID-19 pandemic.

Epidemiology of Traumatic Brain Injury in Georgia: A Prospective Hospital-Based Study

Purpose

Traumatic brain injury (TBI) is one of the major causes of morbidity and mortality worldwide, disproportionally affecting low- and middle-income countries (LMICs). Epidemiological characteristics of TBI at a national level are absent for most LMICs including Georgia. This study aimed to establish the registries and assess causes and outcomes in TBI patients presenting to two major trauma hospitals in the capital city –Tbilisi.

Patients and Methods

The prospective observational study was conducted at Acad. O. Gudushauri National Medical Center and M. Iashvili Children’s Central Hospital from March, 1 through August, 31, 2019. Patients of all age groups admitted to one of the study hospitals with a TBI diagnosis were eligible for participation. Collected data were uploaded using the electronic data collection tool –REDCap, analyzed through SPSS software and evaluated to provide detailed information on TBI-related variables and outcomes using descriptive statistics.

Results

Overall, 542 hospitalized patients were enrolled during the study period, about 63% were male and the average age was 17.7. The main causes of TBI were falls (58%) and struck by or against an object (22%). The 97% suffered from mild TBI (GCS 13–15). Over 23% of patients arrived at the hospital more than 1 hour after injury and 25% after more than 4-hours post-injury. Moderate and severe TBI were associated with an increased hospital length of stay. Mortality rate of severe TBI was 54%.

Conclusion

This study provides important information on the major epidemiological characteristics of TBI in Georgia, which should be considered for setting priorities for injury management.

Sex Differences in Neuromodulation Treatment Approaches for Traumatic Brain Injury: A Scoping Review

OBJECTIVE

Neuromodulatory brain stimulation interventions for traumatic brain injury (TBI)-related health sequelae, such as psychiatric, cognitive, and pain disorders, are on the rise. Because of disproportionate recruitment and epidemiological reporting of TBI-related research in men, there is limited understanding of TBI development, pathophysiology, and treatment intervention outcomes in women. With data suggesting sex-related variances in treatment outcomes, it is important that these gaps are addressed in emerging, neuromodulatory treatment approaches for TBI populations.

METHODS

Four research databases (PubMED, EMBASE, CINAHL, and PsycINFO) were electronically searched in February 2020.

DESIGN

This PRISMA Scoping Review (PRISMA-ScR)-guided report contextualizes the importance of reporting sex differences in TBI + neuromodulatory intervention studies and summarizes the current state of reporting sex differences when investigating 3 emerging interventions for TBI outcomes.

RESULTS

Fifty-four studies were identified for the final review including 12 controlled trials, 16 single or case series reports, and 26 empirical studies. Across all studies reviewed, 68% of participants were male, and only 7 studies reported sex differences as a part of their methodological approach, analysis, or discussion.

CONCLUSION

This review is hoped to update the TBI community on the current state of evidence in reporting sex differences across these 3 neuromodulatory treatments of post-TBI sequelae. The proposed recommendations aim to improve future research and clinical treatment of all individuals suffering from post-TBI sequelae.

Neuropsychiatric Presentations due to Traumatic Brain Injury in Cognitively Normal Older Adults

Neuropsychiatric symptoms (NPS) are common sequelae of traumatic brain injuries (TBI) among adults. However, little is known about NPS associated with a history of TBI in adults relative to adults without a history of TBI and to what extent NPS may be modulated by sex and other factors. Using the National Alzheimer's Coordinating Center Uniform Data Set, we examined the association between Neuropsychiatric Inventory-Questionnaire (NPI-Q) scores in cognitively normal older adults with and without a history of TBI. A binomial logistic regression model was used to examine NPI-Q domains in adults with a history of TBI (n = 266) versus without a history of TBI (n = 1508). History of TBI, sex, age, and body mass index were used as covariates. Adults with a history of TBI had a greater probability of exhibiting agitation, anxiety, apathy, disinhibition and aberrant motor behavior relative to adults without a history of TBI. In terms of sex differences, males with and without a history of TBI had an increased likelihood of agitation, apathy, disinhibition, and apnea, whereas females had an increased likelihood of anxiety and insomnia relative to males. Our study confirms that history of TBI is associated with an increased prevalence of specific NPS, including agitation, anxiety, apathy, disinhibition, and aberrant motor behavior. Given that the aforementioned NPS are linked through different pathways, damage to any of them may cause an alteration in behavior. As well, NPS appear to be modulated by sex, with symptoms differing between males and females. Our research suggests future studies examining NPS sequelae of TBI should adjust for sex.

Traumatic Brain Injury and Alcohol Drinking Alter Basolateral Amygdala Endocannabinoids in Female Rats

Traumatic brain injury (TBI) affects approximately 3 million Americans yearly and increases vulnerability to developing psychiatric comorbidities. Alcohol use disorder (AUD) is the most prevalent psychiatric diagnosis preceding injury and TBI may increase subsequent alcohol use. The basolateral amygdala (BLA) is a limbic structure commonly affected by TBI that is implicated in anxiety and AUD. Endocannabinoids (eCBs) regulate synaptic activity in the BLA, and BLA eCB modulation alters anxiety-like behavior and stress reactivity. Previous work from our laboratories showed that systemic eCB degradation inhibition ameliorates TBI-induced increases in anxiety-like behavior and motivation to respond for alcohol in male rats. Here, we used a lateral fluid percussion model to test moderate TBI effects on anxiety-like behavior, alcohol drinking, and eCB levels and cell signaling in BLA, as well as the effect of alcohol drinking on anxiety-like behavior and the BLA eCB system, in female rats. Our results show that TBI does not promote escalation of operant alcohol self-administration or increase anxiety-like behavior in female rats. In the BLA, TBI and alcohol drinking alter tissue amounts of 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (anandamide; AEA) 1 h post-injury, and 2-AG levels remain low 11 days post-injury. Eleven days after injury, BLA pyramidal neurons were hyperexcitable, but measures of synaptic transmission and eCB signaling were unchanged. These data show that TBI impacts BLA 2-AG tissue levels, that this effect is modified by alcohol drinking, and also that TBI increases BLA cell excitability.