Ethanol reduces metabolic uncoupling following experimental head injury

The impact of minimum unit pricing on traumatic brain injury in Scotland: a retrospective cohort study of routine national data

BACKGROUND

Traumatic brain injury (TBI) is a common cause of disability and mortality and is associated with alcohol consumption. On 1st May 2018, the Scottish Government introduced Minimum Unit Pricing (MUP) legislation which set the floor price at which alcohol can be sold to 50 pence per unit. While MUP has led to a 7.6% decrease in off trade alcohol purchases, there are limited studies investigating the clinical impact of this legislation. This study aims to explore the impact of MUP on traumatic brain injury in Scotland.

METHODS

Retrospective cohort study using routinely collected national data collated by the Scottish Trauma Audit Group. Data were requested for all TBI incidents from 1st May to 31st December for both 2017 and 2018. Primary outcome was alcohol-related TBI. Secondary outcomes were injury mechanism, injury severity, clinical course, and short-term mortality. Analysis was conducted using multiple regression models adjusted for age, sex, season, and deprivation.

RESULTS

A total of 1166 patients (66% male, and 46% in the 60-79-year bracket) were identified. Alcohol-related TBI was evident in 184 of 509 (36%) patients before MUP and in 239 of 657 (36%) patients injured after its implementation (p = 0.638). Further, there was no change in injury mechanism, injury severity, hospital course and short-term mortality of TBI after MUP.

CONCLUSIONS

MUP has not resulted in a change in alcohol-related TBI nor in the mechanism and severity of TBI. Limitations in two-point analysis mean that findings should be interpreted with caution and further studies investigating the clinical outcomes of MUP must be conducted.

Outcome and survival of surgically treated acute subdural hematomas and postcraniotomy hematomas - A retrospective cohort study

Background

The morbidity and mortality of acute subdural hematoma (aSDH) remains high. Several factors have been reported to affect the outcome and survival of these patients. In this study, we explored factors potentially associated with the outcome and survival of surgically treated acute subdural hematoma (aSDH), including postcraniotomy hematomas (PCHs).

Methods

This retrospective cohort study was conducted in a single tertiary university hospital between 2008 and 2012 and all aSDH patients that underwent surgical intervention were included. A total of 132 cases were identified for collection of demographics, clinical, laboratory, and imaging data. Univariate and multivariable analyses were performed to assess factors associated with three-month Glasgow Outcome Scale (GOS) and survival at one- and five-year.

Results

In this study, PCH (n = 14, 10.6%) was not associated with a worse outcome according to the 3- month GOS (p = 0.37) or one (p = 0.34) and five-year (p = 0.37) survival. The multivariable analysis showed that the volume of initial hematoma (p = 0.009) and Abbreviated Injury Scale score (p = 0.016) were independent predictors of the three-month GOS. Glasgow Coma Scale (GCS) score (p < 0.001 and p = 0.037) and age (p = 0.048 and p = 0.003) were predictors for one and five-year survival, while use of antiplatelet drug (p = 0.030), neuroworsening (p = 0.005) and smoking (p = 0.026) were significant factors impacting one year survival. In addition, blood alcohol level on admission was a predictor for five-year survival (p = 0.025).

Conclusions

These elucidations underscore that, although PCHs are pertinent, a comprehensive appreciation of multifarious variables is indispensable in aSDH prognosis. These findings are observational, not causal. Expanded research endeavors are advocated to corroborate these insights.

Alcohol intake before injury and functional and survival outcomes after traumatic brain injury: Pan-Asian trauma outcomes study (PATOS)

There are controversies about the effects of alcohol intake shortly before injury on prognosis of traumatic brain injury (TBI) patients. We investigated the association between alcohol intake and functional/survival outcomes in TBI patients, and whether this effect varied according to age and sex. This was a prospective international multicenter cohort study using the Pan-Asian trauma outcomes study registry in Asian-Pacific countries, conducted on adult patients with TBI who visited participating hospitals. The main exposure variable was alcohol intake before injury, and the main outcomes were poor functional recovery (modified Rankin Scale score, 4-6) and in-hospital mortality. Multivariable logistic regression analyses were conducted to estimate the effects of alcohol intake on study outcomes. Interaction analysis between alcohol intake and age/sex were also performed. Among the study population of 12,451, 3263 (26.2%) patients consumed alcohol before injury. In multivariable logistic regression analysis, alcohol intake was associated with lower odds for poor functional recovery [4.4% vs 6.6%, a odds ratio (95% confidence interval): 0.68 (0.56-0.83)] and in-hospital mortality (1.9% vs 3.1%, 0.64 [0.48-0.86]). The alcohol intake had interaction effects with sex for poor functional recovery: 0.59 (0.45-0.75) for male and 0.94 (0.60-1.49) for female (P for-interaction < .01), whereas there were no interaction between alcohol intake and age. In TBI patients, alcohol intake before injury was associated with lower odds of poor functional recovery and in-hospital mortality, and these effects were maintained in the male group in the interaction analyses.

Vices-paradox in trauma: Positive alcohol and drug screens associated with decreased mortality

BACKGROUND

Improved survival in trauma patients with acute alcohol intoxication has been previously reported. The effect of illegal and controlled substances on mortality is less clear. We hypothesized that alcohol, illegal and controlled substances are each independently associated with lower odds of mortality in adult trauma patients.

METHODS

The Trauma Quality Improvement Program (2010-2016) was queried for patients screening positive for alcohol, illegal or controlled substances on admission. A multivariate logistic regression analysis was used to determine odds of mortality. A similar analysis was used after stratification by injury severity scale (ISS).

RESULTS

From 1,299,705 adult patients, 660,135 were screened for substance use. Of these patients, 497,872 were male, 227,995 (34.5 %) screened positive for alcohol, 155,437 (23.5 %) for illegal substances and 90,259 (13.7 %) for controlled substances. Mortality rate was 6.2 % with alcohol, 5.1 % with illegal substances, and 5.7 % with controlled substances compared to 8.0 % with no substance use (p < 0.001). After controlling for covariates, all groups had lower odds of mortality: alcohol (OR = 0.88, CI = 0.84-0.92, p < 0.001), illegal substances (OR = 0.83, CI = 0.77-0.90, p < 0.001), controlled substances (OR = 0.72, CI = 0.67-0.79, p < 0.001). When stratified by ISS, alcohol and illegal substances continued to be associated with decreased mortality until ISS 50. Controlled substances were associated with decreased mortality when ISS > 16.

CONCLUSION

Patients positive for alcohol, illegal or controlled substances have 12 %, 17 %, and 28 % decreased odds of mortality, respectively. This paradoxical association should be confirmed with future clinical studies and merits basic science research to identify biochemical or physiological components conferring a protective effect on survival in trauma patients.

The impact of exercise, sleep, and diet on neurocognitive recovery from mild traumatic brain injury in older adults: A narrative review

Mild traumatic brain injury (mTBI) accounts for a large majority of traumatic brain injuries sustained globally each year. Older adults, who are already susceptible to age-related declines to neurocognitive health, appear to be at an increased risk of both sustaining an mTBI and experiencing slower or impaired recovery. There is also growing evidence that mTBI is a potential risk factor for accelerated cognitive decline and neurodegeneration. Lifestyle-based interventions are gaining prominence as a cost-effective means of maintaining cognition and brain health with age. Consequently, inter-individual variations in exercise, sleep, and dietary patterns could influence the trajectory of post-mTBI neurocognitive recovery, particularly in older adults. This review synthesises the current animal and human literature centred on the mechanisms through which lifestyle-related habits and behaviours could influence acute and longer-term neurocognitive functioning following mTBI. Numerous neuroprotective processes which are impacted by lifestyle factors have been established in animal models of TBI. However, the literature is characterised by a lack of translation to human samples and limited appraisal of the interaction between ageing and brain injury. Further research is needed to better establish the therapeutic utility of applying lifestyle-based modifications to improve post-mTBI neurocognitive outcomes in older adults.

Isolated traumatic brain injury: Routine intubation for Glasgow Coma Scale 7 or 8 may be harmful!

INTRODUCTION

Despite strong recommendations, there is no direct evidence supporting routine intubation of trauma patients with Glasgow Coma Scale (GCS) score of 7 or 8. We hypothesized that routine intubation may not be beneficial in isolated blunt head injury.

METHODS

A retrospective Trauma Quality Improvement Program study, including adult blunt trauma patients with GCS score of 7 or 8 and isolated head injury, was performed. Epidemiological and clinical characteristics, neurosurgical procedures, timing of intubation, and outcome variables were collected. The study population was stratified by the intubation procedure: immediate intubation (≤1 hour of admission), delayed intubation (>1 hour of admission), and no intubation. Multivariable regression analysis was used to determine risk factors for mortality and complications, as well as factors predictive of the decision to intubate.

RESULTS

Of 2,727 patients with GCS score of 7 or 8 and isolated blunt head trauma, 1,866 patients (68.4%) were intubated within 1 hour of admission (immediate intubation), 223 (8.2%) had an intubation >1 hour of admission (delayed intubation), and 638 patients (23.4%) were not intubated at all. After correcting for age, sex, overall comorbidities, tachycardia, GCS, alcohol, illegal drug use, and head injury severity, immediate intubation was independently associated with higher mortality (odds ratio, 1.79; 95% confidence interval, 1.31-2.44; p < 0.001) and more overall complications (odds ratio, 2.46; 95% confidence interval, 1.62-3.73; p < 0.001). Increasing head Abbreviated Injury Scale (AIS) score, GCS score of 7, and tachycardia were identified as independent clinical factors associated with the decision to intubate. A policy of intubating all isolated blunt head injury patients 45 years or younger with head AIS score of 5 and GCS score of 7 would have improved intubation management, with seven immediate instead of delayed intubations and only three potentially unnecessary intubations.

CONCLUSION

In patients with GCS score of 7 or 8 and isolated head injury, immediate intubation was associated with higher mortality and more overall complications. Intubation management could have been improved by intubating all patients younger than 45 years with head AIS score of 5 and a GCS score of 7 on admission.

LEVEL OF EVIDENCE

Therapeutic, level III.

Effects of acute alcohol consumption on neuronal activity and cerebral vasomotor response

Introduction

In the majority of European countries, driving after drinking small-moderate amount of alcohol is legal. Motivated by our previous studies on cerebral hemodynamics, we aimed to study whether a small-moderate blood alcohol content (BAC), at which driving is legal in some countries (0.8 g/L), influences the neuronal activity, neurovascular coupling, and cerebral vasoreactivity.

Methods

Analyses of pattern-reversal visual evoked potential (VEP) and transcranial Doppler (TCD) examinations were performed in thirty young healthy adults before and 30 min after alcohol consumption. Cerebral vasoreactivity was evaluated by breath holding test in both middle cerebral arteries. By using a visual cortex stimulation paradigm, visually evoked flow velocity response during reading was measured in both posterior cerebral arteries (PCA).

Results

The BAC was 0.82 g/L and 0.94 g/L 30 and 60 min after drinking alcohol, respectively. Latency of the VEP P100 wave increased after alcohol consumption. Resting absolute flow velocity values increased, whereas pulsatility indices in the PCA decreased after alcohol ingestion, indicating vasodilation of cerebral microvessels. Breath holding index and the visually evoked maximum relative flow velocity increase in the PCA and steepness of rise of the flow velocity curve were smaller after than before alcohol consumption.

Conclusion

BAC close to a legal value at which driving is allowed in some European countries inhibited the neuronal activity and resulted in dilation of cerebral arterioles. Cerebral vasodilation may explain the decrease of cerebral vasoreactivity and might contribute to the disturbance of visually evoked flow response after alcohol consumption.

When Two Wrongs Make a Right: The Effect of Acute and Chronic Binge Drinking on Traumatic Brain Injury Outcomes in Young Adult Female Rats

Alcohol is the most commonly abused drug by young adults across North America. Although alcohol consumption itself incurs a risk of neurological damage, it is also a significant risk factor for traumatic brain injury (TBI). TBI among young adults is described as a modern healthcare epidemic. The drastic changes occurring within their neurological networks put young adults at greater risk for developing long-term post-traumatic deficits. Contradictory findings have been indicated regarding the effects of alcohol consumption on TBI outcomes in adults, with some studies demonstrating detrimental effects, whereas others suggest neuroprotective abilities. However, little is known about the effects of alcohol consumption on TBI outcomes during the sensitive stage of early adulthood. Young adult female Sprague-Dawley rats were randomly assigned to one of six experimental conditions: Pre-injury alcohol+TBI; Pre-injury alcohol+Sham; Pre- and Post-injury alcohol+TBI; Pre- and Post-injury alcohol+Sham; No alcohol+TBI; No alcohol+Sham. Alcohol consumption groups received an amount of 10% v/v ethanol solution based on the animals' weight. Following the injury, the rats were subjected to a behavioral test battery to assess post-concussive symptomology. Overall, chronic binge drinking significantly improved TBI outcomes related to motor coordination and balance, whereas binge drinking in general significantly decreased anxiety-like behaviors. Additionally, in many cases, chronic binge drinking appears to return the TBI animal's behavioral outcomes to levels comparable to those of the no alcohol sham animals. Thus, the results suggest that alcohol may exhibit neuroprotective abilities in the context of early adulthood TBI.

Alcohol in Traumatic Brain Injury: Toxic or Therapeutic?

BACKGROUND

Alcohol (EtOH) poses a challenge in traumatic brain injuries (TBIs) given its metabolic and neurologic impact. Studies have had opposing results regarding mortality and complication rates in the intoxicated TBI patient. We hypothesized that trauma mechanism, brain injury severity, and blood alcohol concentration (BAC) would influence the impact of EtOH on mortality in TBI.

METHODS

We performed a single-institution retrospective review of consecutive adult trauma patients tested for EtOH and a diagnosis of TBI. The primary outcome was mortality, and secondary outcomes included infectious complications. The primary analysis included univariate and multivariate regression comparing mortality between intoxicated and sober patients, at different values of BAC, different brain injury severities, and among mechanisms of trauma.

RESULTS

Admission EtOH was assessed in 583 patients with TBI, with 256 testing positive for EtOH and 327 testing negative. Overall, EtOH was associated with lower mortality on univariate analysis (4.7% versus 8.9%, P = 0.05) but not on multivariate analysis (P = 0.21). There was no effect of EtOH on mortality when patients were stratified by brain injury severity or among penetrating trauma victims. However, EtOH was associated with lower overall infectious complications on univariate and multivariate regression. Finally, EtOH was predictive of mortality with an area under the receiver operator characteristic curve of 0.83.

CONCLUSIONS

We found that EtOH is not associated with mortality in the patient with TBI, suggesting no causative effect. However, EtOH showed some predictability of mortality based on a receiver operator characteristic analysis. Interestingly, EtOH was associated with lower infectious complications, suggesting an immunomodulatory effect of EtOH in TBI.

Neuroprotective effect of ethanol and Modafinil on focal cerebral ischemia in rats

Ethanol is known as an effective agent against cerebral lesions after ischemia. Modafinil is a stimulant of the central nervous system (CNS) with antioxidant properties. We assessed the neuroprotective effect of modafinil in combination with ethanol after focal cerebral ischemia. Male wistar rats weighing 280-300 g were divided into nine groups (n = 12 each group): The groups consisted of the MCAO (middle cerebral artery occlusion) group (i.e. ischemia without treatment); the vehicle group(Dimethylsulfoxide); the modafinil group including three subgroups which pretreated with Modafinil (10, 30, 100 mg/kg), respectively, for seven days prior to the induction of MCAO; the ethanol group which received 1.5g/kg ethanol at the time of reperfusion; and modafinil+ethanol group which was divided into three subgroups that received three doses of modanifil (10, 30,100 mg/kg), respectively, for seven days prior to MCAO as well as ethanol at the time of reperfusion. Transient cerebral ischemia was induced by 60-min intraluminal occlusion of the right middle cerebral artery. Edema, infarct volume, glial scar formation (gliosis) and apoptosis were analyzed. The ethanol alone treatment (with a less significant effect), modafinil (in a dose-dependent way), and the combination of modafinil and ethanol significantly decreased the brain infarct volume, edema, apoptosis, and gliosis (P ≤ 0.05). Additionally, modafinil+ethanol mediated the restoration of aerobic metabolism and hyper-glycolysis suppress, thereby resulting in an increase in pyruvate dehydrogenase and a decrease in lactate dehydrogenase activity, respectively, which ultimately reduced oxidative reperfusion injury. These results demonstrate that pretreatment with modafinil (100 mg/kg) and modafinil+ethanol(1.5 g/kg) may prevent ischemic brain injuries.

Association of Alcohol With Mortality After Traumatic Brain Injury

Although alcohol exposure results in reduced mortality after traumatic brain injury (TBI) in animal models, clinical trials based on proposed mechanisms have been disappointing and have reported conflicting results. Methodological issues common to many of these clinical studies may have contributed to the spurious results. Our objective was to evaluate the association between blood alcohol concentration (BAC) and in-hospital mortality after TBI, and overcome methodological problems of prior studies. We conducted a retrospective cohort study on individuals treated for isolated TBI (n = 1,084) at the R Adams Cowley Shock Trauma Center (Baltimore, Maryland) from 1997 to 2012. We excluded individuals with injury to other body regions and examined multiple cutpoints of BAC. Our primary outcome was in-hospital mortality. In adjusted logistic regression models, the upper level of each blood alcohol categorization from 0.10 g/dL (odds ratio = 0.63, 95% confidence interval: 0.40, 0.97) through 0.30 g/dL (odds ratio = 0.25, 95% confidence interval: 0.08, 0.84) was associated with reduced risk of mortality after TBI compared with individuals with undetectable BAC. In sensitivity analyses among individuals without penetrating brain injuries (95% firearm-related) (n = 899), the protective association was eliminated. This study provides evidence that the observed protective association between BAC and in-hospital mortality after TBI resulted from bias introduced by inclusion of penetrating injuries.

Acute Alcohol Exposure and Risk of Mortality of Patients with Traumatic Brain Injury: A Systematic Review and Meta-Analysis

After traumatic brain injury (TBI), patients usually live with significant disability and socioeconomic burdens. Acute exposure to alcohol is considered a major risk factor for TBI. Numerous studies have examined whether alcohol exposure is related to the risk of mortality in patients with TBI, yet the results remain inconsistent. We performed a meta-analysis to assess whether acute alcohol exposure affects the mortality rate of TBI patients. We searched PubMed, EMBASE, and the Cochrane Library up to November 2015 for relevant studies. We screened studies based on their inclusion criteria and selected the studies that reported mortality rate, which included 18 observational studies. We used R to analyze the included data. An initial result showed that the presence of a positive blood alcohol concentration (BAC) had no significant relation with mortality rate (OR = 0.92, 95% CI = 0.83 to 1.01), but there was notable heterogeneity along with variable results according to sensitivity analysis. For the BAC-positive population, low BAC (1 to 100 mg/dl) carried a higher risk of mortality than moderate BAC (100 to 230 mg/dl) (OR = 1.40, 95% CI = 1.09 to 1.81), moderate and high BAC as a single category (>100 mg/dl) (OR = 1.57, 95% CI = 1.28 to 1.94), or high BAC (>230 mg/dl) (OR = 1.76, 95% CI = 1.34 to 2.30). However, moderate BAC did not increase the mortality risk when compared with high BAC (OR = 1.20, 95% CI = 0.89 to 1.63). Whether positive BAC at the time of admission after TBI reduces mortality rate compared with the rate under negative BAC remains unknown. In addition, low BAC (1 to 100 mg/dl) poses a risk of mortality compared with higher BAC. Further studies assessing the effect of alcohol between the BAC-positive group and the BAC-negative group are still needed.

Patient mortality following alcohol use and trauma: a propensity-matched analysis

OBJECTIVE

To examine the outcomes of trauma patients who tested positive for alcohol at the time of hospital arrival versus those who tested negative.

METHODS

Data were pulled from the National Trauma Data Bank (2007-2010). All injured patients who were ≥14 years of age, sustained a "blunt" or "penetrating" injury, had complete systolic blood pressure (SBP) and heart rate (HR) records, were taken to a level 1 or 2 trauma center, and who received a confirmed blood alcohol test were included in the study. Any blood alcohol concentration (BAC) above the legal limit (≥0.08 g/dL) was considered "positive" for alcohol, and if no alcohol was identified it was considered "negative". Patients' demography and clinical information were compared across groups using Chi-square and Wilcoxon rank sum tests. Logistic regression, propensity score matching, and a follow-up paired analysis were also performed.

RESULTS

Of 279,460 total patients, around one-third of the patients (92,960) tested positive for BAC. There were clear demographic differences found between the two groups regarding age, gender, race, and injury type. There was also a significantly higher mortality rate (4.3 vs. 3.1%, P < 0.001) and a longer hospital length of stay (4 vs. 3 days, P < 0.001) found in the alcohol-negative group. Propensity score matching was also performed resulting in 92,959 patients per group. Using the paired data, the overall mortality observed was 3.1 vs. 3.3% (P = 0.035) between the alcohol-positive and alcohol-negative groups, respectively. There was no significant difference noted in the total hospital length of stay (median: 3 vs. 4 days, P = 0.84).

CONCLUSION

Patients who tested positive for alcohol following a traumatic injury showed no clinically significant reduction in mortality and no significant difference in total hospital length of stay.

Impact of day-of-injury alcohol consumption on outcomes after traumatic brain injury: A meta-analysis

Although a known risk factor for traumatic brain injury (TBI), alcohol has been found to both promote and protect against secondary brain damage. However, it is presently unclear whether the cognitive, psychological and medical/functional outcomes of adults who have consumed alcohol prior to sustaining a TBI differ from those who have not. This meta-analysis examined the outcomes of groups that differed in terms of their day-of-injury (DOI) blood alcohol levels (BALs) by comparing positive with zero BAL (BAL⁺/BAL^-) and high with low BAL (BAL^high/BAL^low) samples. The PubMed, PsycINFO, EMBASE, and Scopus databases were searched from inception until the end of March 2015. Hedge's g effects (continuous data) and odds ratios (categorical data) were calculated for 27 studies that compared either the outcomes of BAL⁺ and BAL^- groups or BAL^high and BAL^low groups. BAL⁺ was associated with significantly poorer cognitive outcomes (overall and on general tests) and higher levels of disability, and BAL^high was associated with shorter stays in intensive care. More generally, however, most effect sizes were small to low-moderate in size, non-significant and inconsistent in their direction. Although DOI alcohol consumption increases the risk of sustaining a TBI, it is not consistently associated with better or worse outcomes, other than subtle cognitive deficits; the source of which remains to be determined.

Ethanol and isolated traumatic brain injury

The aim of this systematic review was to determine whether ethanol is neuroprotective or associated with adverse effects in the context of traumatic brain injury (TBI). Approximately 30-60% of TBI patients are intoxicated with ethanol at the time of injury. We performed a systematic review of the literature using a combination of keywords for ethanol and TBI. Manuscripts were included if the population studied was human subjects with isolated moderate to severe TBI, acute ethanol intoxication was studied as an exposure variable and mortality reported as an outcome. The included studies were assessed for heterogeneity. A meta-analysis was performed and the pooled odds ratio (OR) for the association between ethanol and in-hospital mortality reported. There were seven studies eligible for analysis. A statistically significant association favouring reduced mortality with ethanol intoxication was found (OR 0.78; 95% confidence interval 0.73-0.83). Heterogeneity among selected studies was not statistically significant (p=0.25). Following isolated moderate-severe TBI, ethanol intoxication was associated with reduced in-hospital mortality. The retrospective nature of the studies, varying definitions of brain injury, degree of intoxication and presence of potential confounders limits our confidence in this conclusion. Further research is recommended to explore the potential use of ethanol as a therapeutic strategy following TBI.

Acute alcohol intoxication and long-term outcome in patients with traumatic brain injury

The effect of blood alcohol concentration (BAC) on outcome after traumatic brain injury (TBI) is controversial. We sought to assess the independent effect of positive BAC on long-term outcome in patients with TBI treated in the intensive care unit (ICU). We performed a retrospective analysis of 405 patients with TBI, admitted to the ICU of a large urban Level 1 trauma center between January 2009 and December 2012. Outcome was six-month mortality and unfavorable neurological outcome (defined as a Glasgow Outcome Scale score of 1 [death], 2, [vegetative state], or 3 [severe disability]). Patients were categorized by admission BAC into: no BAC (0.0‰; n=99), low BAC (<2.3‰; n=140) and high BAC (≥2.3‰; n=166). Logistic regression analysis, adjusting for baseline risk and severity of illness, was used to assess the independent effect of BAC on outcome (using the no BAC group as the reference). Overall six-month mortality was 25% and unfavorable outcome was 46%. Multivariate analysis showed low BAC to independently reduce risk of six-month mortality compared with no BAC (low BAC adjusted odds ratio [AOR] 0.41, 95% confidence interval [CI] 0.19-0.88, p=0.021) and high BAC (AOR 0.58, 95% CI 0.29-1.15, p=0.120). Furthermore, a trend towards reduced risk of six-month unfavorable neurological outcome for patients with positive BAC, compared to patients with negative BAC, was noted, although this did not reach statistical significance (low BAC AOR 0.65, 95% CI 0.34-1.22, p=0.178, and high BAC AOR 0.59, 95% CI 0.32-1.09, p=0.089). In conclusion, low admission BAC (<2.3‰) was found to independently reduce risk of six-month mortality for patients with TBI, and a trend towards improved long-term neurological outcome was found for BAC-positive patients. The role of alcohol as a neuroprotective agent warrants further studies.

The effect of alcohol intoxication on mortality of blunt head injury

Alcohol is found to have neuroprotection in recent studies in head injuries. We investigated the association of blood alcohol concentration (BAC) with mortality of patients with blunt head injury after traffic accident. All patients sustaining blunt head injury caused by traffic accident brought to our emergency department who had obtained a brain computed tomography scans and BAC were analyzed. Patients with unknown mechanisms, transfers from outside hospitals, and incomplete data were excluded. Logistic regression was used to identify independent predictors of mortality. During the study period, 3,628 patients with brain computed tomography (CT) were included. Of these, BAC was measured in 556 patients. Patients with the lowest BAC (less than 8 mg/dl) had lower mortality; intoxicated patients with BAC between 8 and less than 100 mg/dl were associated with significantly higher mortality than those patients in other intoxicated groups. Adjusted logistic regression demonstrated higher BAC group and Glasgow coma scale (GCS) scores, and lower ISS and age were identified as independent predictors of reduced mortality. In our study, we found that patients who had moderate alcohol intoxication had higher risk of mortality. However, higher GCS scores, lower ISS, and younger age were identified as independent predictors of reduced mortality in the study patients.

Effect of alcohol in traumatic brain injury: is it really protective?

BACKGROUND

Studies have proposed a neuroprotective role for alcohol (ETOH) in traumatic brain injury (TBI). We hypothesized that ETOH intoxication is associated with mortality in patients with severe TBI.

METHODS

Version 7.2 of the National Trauma Data Bank (2007-2010) was queried for all patients with isolated blunt severe TBI (Head Abbreviated Injury Score ≥4) and blood ETOH levels recorded on admission. Primary outcome measure was mortality. Multivariate logistic regression analysis was performed to assess factors predicting mortality and in-hospital complications.

RESULTS

A total of 23,983 patients with severe TBI were evaluated of which 22.8% (n = 5461) patients tested positive for ETOH intoxication. ETOH-positive patients were more likely to have in-hospital complications (P = 0.001) and have a higher mortality rate (P = 0.01). ETOH intoxication was an independent predictor for mortality (odds ratio: 1.2, 95% confidence interval: 1.1-2.1, P = 0.01) and development of in-hospital complications (odds ratio: 1.3, 95% confidence interval: 1.1-2.8, P = 0.009) in patients with isolated severe TBI.

CONCLUSIONS

ETOH intoxication is an independent predictor for mortality in patients with severe TBI patients and is associated with higher complication rates. Our results from the National Trauma Data Standards differ from those previously reported. The proposed neuroprotective role of ETOH needs further clarification.

Controlled cortical impact results in an extensive loss of dendritic spines that is not mediated by injury-induced amyloid-beta accumulation

The clinical manifestations that occur after traumatic brain injury (TBI) include a wide range of cognitive, emotional, and behavioral deficits. The loss of excitatory synapses could potentially explain why such diverse symptoms occur after TBI, and a recent preclinical study has demonstrated a loss of dendritic spines, the postsynaptic site of the excitatory synapse, after fluid percussion injury. The objective of this study was to determine if controlled cortical impact (CCI) also resulted in dendritic spine retraction and to probe the underlying mechanisms of this spine loss. We used a unilateral CCI and visualized neurons and dendtritic spines at 24 h post-injury using Golgi stain. We found that TBI caused a 32% reduction of dendritic spines in layer II/III of the ipsilateral cortex and a 20% reduction in the dendritic spines of the ipsilateral dentate gyrus. Spine loss was not restricted to the ipsilateral hemisphere, however, with similar reductions in spine numbers recorded in the contralateral cortex (25% reduction) and hippocampus (23% reduction). Amyloid-β (Aβ), a neurotoxic peptide commonly associated with Alzheimer disease, accumulates rapidly after TBI and is also known to cause synaptic loss. To determine if Aβ contributes to spine loss after brain injury, we administered a γ-secretase inhibitor LY450139 after TBI. We found that while LY450139 administration could attenuate the TBI-induced increase in Aβ, it had no effect on dendritic spine loss after TBI. We conclude that the acute, global loss of dendritic spines after TBI is independent of γ-secretase activity or TBI-induced Aβ accumulation.

Acute alcohol intoxication, diffuse axonal injury and intraventricular bleeding in patients with isolated blunt traumatic brain injury

OBJECTIVE

The influence of blood alcohol level (BAL) on outcome remains unclear. This study investigated the relationships between BAL, type and number of diffuse axonal injury (DAI), intraventricular bleeding (IVB) and 6-month outcome.

METHODS

This study reviewed 419 patients with isolated blunt traumatic brain injury. First, it compared clinical and radiological characteristics between patients with good recovery and disability. Second, it compared BAL among DAI lesions. Third, it evaluated the correlation between the BAL and severity of IVB, number of DAI and corpus callosum injury lesions.

RESULTS

Regardless of BAL, older age, male gender, severe Glasgow Coma Scale score (<9), abnormal pupil, IVB and lesion on genu of corpus callosum were significantly related to disability. There were no significant differences between the BAL and lesions of DAI. Simple regression analysis revealed that there were no significant correlation between BAL and severity of IVB, number of DAI and corpus callosum injury lesions.

CONCLUSIONS

Acute alcohol intoxication was not associated with type and number of DAI lesion, IVB and disability. This study suggested that a specific type of traumatic lesion, specifically lesion on genu of corpus callosum and IVB, might be more vital for outcome.

Insights into the metabolic response to traumatic brain injury as revealed by (13)C NMR spectroscopy

The present review highlights critical issues related to cerebral metabolism following traumatic brain injury (TBI) and the use of (13)C labeled substrates and nuclear magnetic resonance (NMR) spectroscopy to study these changes. First we address some pathophysiologic factors contributing to metabolic dysfunction following TBI. We then examine how (13)C NMR spectroscopy strategies have been used to investigate energy metabolism, neurotransmission, the intracellular redox state, and neuroglial compartmentation following injury. (13)C NMR spectroscopy studies of brain extracts from animal models of TBI have revealed enhanced glycolytic production of lactate, evidence of pentose phosphate pathway (PPP) activation, and alterations in neuronal and astrocyte oxidative metabolism that are dependent on injury severity. Differential incorporation of label into glutamate and glutamine from (13)C labeled glucose or acetate also suggest TBI-induced adaptations to the glutamate-glutamine cycle.

Effects of the neurotoxin MPTP and pargyline protection on extracellular energy metabolites and dopamine levels in the striatum of freely moving rats

The neurotoxin MPTP is known to induce dopamine release and depletion of ATP in the striatum of rats. Therefore, we studied the changes induced by MPTP and pargyline protection both on striatal dopamine release and on extracellular energy metabolites in freely moving rats, using dual asymmetric-flow microdialysis. A dual microdialysis probe was inserted in the right striatum of rats. MPTP (25mg/kg, 15mg/kg, 10mg/kg) was intraperitoneally administered for three consecutive days. MAO-B inhibitor pargyline (15mg/kg) was systemically administered before neurotoxin administration. The first MPTP dose induced an increase in dialysate dopamine and a decrease of DOPAC levels in striatal dialysate. After the first neurotoxin administration, increases in striatal glucose, lactate, pyruvate, lactate/pyruvate (L/P) and lactate/glucose (L/G) ratios were observed. Subsequent MPTP administrations showed a progressive reduction of dopamine, glucose and pyruvate levels with a concomitant further increase in lactate levels and L/P and L/G ratios. At day 1, pargyline pre-treatment attenuated the MPTP-induced changes in all studied analytes. Starting from day 2, pargyline prevented the depletion of dopamine, glucose and pyruvate while reduced the increase of lactate, L/P ratio and L/G ratio. These in vivo results suggest a pargyline neuroprotection role against the MPTP-induced energetic impairment consequent to mitochondrial damage. This neuroprotective effect was confirmed by TH immunostaining of the substantia nigra.

At low doses ethanol maintains blood-brain barrier (BBB) integrity after hypoxia and reoxygenation: a brain slice study

Post-ischemia ethanol (EtOH) treatments have been shown to exhibit neuroprotective effects in stroke. However, the mechanisms underlying these effects and those on blood-brain barrier (BBB) integrity have yet to be elucidated. In the present study, we determined whether administering differing concentrations of EtOH alter the expressions of BBB integral proteins, including aquaporins-4 and -9 (AQP-4, AQP-9), matrix metallopeptidases-2 and -9 (MMP-2, MMP-9), zonula occludens-1 (ZO-1), and basal lamina (laminin). We employed an organotypic brain slice culture model that utilizes oxygen-glucose deprivation followed by reoxygenation (OGD/R). Brain slices were obtained from 10-day-old Sprague-Dawley rats and divided into the following five groups (n = 8 subjects per group): (1) control, (2) hypoxia (OGD/R), no EtOH, (3) OGD/R and 10 mM EtOH, (4) OGD/R and 30 mM EtOH, and (5) OGD/R and 90 mM EtOH. To assess BBB integrity, levels of AQPs, MMPs, ZO-1, and laminin were determined by Western blot. Compared to control, OGD/R without EtOH significantly increased AQP-4, AQP-9, MMP-2, and MMP-9 levels, while decreasing ZO-1 and laminin levels. All EtOH concentration treatments (groups 3 through 5) significantly reduced the expressions of AQP-4, AQP-9, MMP-2, and MMP-9, compared to the OGD/R, non-alcohol treated slices. Furthermore, compared to the OGD/R without EtOH group, the 30 mM EtOH treatment significantly increased ZO-1 and laminin levels. In contrast, the 90 mM EtOH level neither enhanced the reduction in AQP and MMP levels nor increased ZO-1 or basal lamina expressions observed in the 30 mM treatment. In conclusion, at an optimal dose of 30 mM, EtOH improves the expressions of MMP-2, MMP-9, AQP-4, AQP-9, ZO-1, and basal laminin, previously altered by OGD/R. These effects may indicate a beneficial effect of EtOH on BBB integrity after stroke.

Acute administration of ethanol reduces apoptosis following ischemic stroke in rats

In recent studies, acute ethanol administration appears to play a neuroprotective role during ischemic stroke. We sought to confirm these findings by identifying if ethanol-derived neuroprotection is associated with a reduction in apoptosis. Ethanol at 0.5 and 1.5 g/kg doses was given by intraperitoneal injections to Sprague-Dawley rats after 2h of middle cerebral artery (MCA) occlusion, followed by reperfusion. We quantified apoptotic cell death in each of the treatment groups with ELISA, and measured pro- and anti-apoptotic protein expression with Western blot analysis. Cell death was significantly increased in rats after ischemia and was subsequently significantly reduced by the administration of 1.5 g/kg of ethanol. We found that the 1.5 g/kg dose promoted the expression of pro-survival factors and decreased the expression of apoptotic proteins at 3h after reperfusion. This effect was maintained at 24h for Caspase-3 and apoptosis-inducing factor (AIF), although not for Bcl-2, Bcl-xL, and Bcl-2-associated X (Bax). Administration of 0.5 g/kg of ethanol was not as effective in regulating protein expression as the 1.5 g/kg dose. Our study suggests that administration of ethanol at a dose of 1.5 g/kg after stroke - which provides rat blood alcohol levels equivalent to the legal driving limit - produces a differential protein profile, with increased expression of anti-apoptotic proteins and decrease in pro-apoptotic factors. This results in a significant reduction of neuronal apoptosis and is neuroprotective in ischemia-reperfusion injury.

Neuroprotection conferred by post-ischemia ethanol therapy in experimental stroke: an inhibitory effect on hyperglycolysis and NADPH oxidase activation

Ethanol provides neuroprotection following ischemia/reperfusion. This study assessed ethanol's effect on hyperglycolysis and NADPH oxidase (NOX) activation. Adult, male Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) for 2 h. Three sets of experiments were conducted to determine ethanol's effect on (i) conferring neuroprotection by measuring infarct volume and neurological deficits 24 h post reperfusion; (ii) cerebral glucose metabolism and lactic acidosis by measuring brain and blood glucose concentrations and protein expression of glucose transporter 1 and 3 (GLUT1, GLUT3), phosphofructokinase (PFK), as well as lactic acidosis by measuring lactate dehydrogenase (LDH), and lactate; and (iii) nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activation by detecting enzymatic activity and subunit expression at 3 h after reperfusion. When administered upon reperfusion, ethanol (1.5 g/kg) reduced infarct volume by 40% (p < 0.01) and neurological deficits by 48% at 24 h post reperfusion while reducing (p < 0.01) elevations in glycolytic protein expression and lactate levels during early reperfusion (3 h). Ethanol increased the reductions in cerebral glucose concentration at 3 h post reperfusion by 64% (p < 0.01) while enhancing (p < 0.01) post stroke blood glucose concentration, suggesting a reduced cellular glucose uptake and utilization. Ethanol decreased (p < 0.01) stroke-induced NOX activation by reducing enzymatic activity and gp91(phox) expression by 45% and 38%, respectively. Post-ischemia ethanol treatment exerts neuroprotection through attenuation of hyperglycolysis and associated NOX activation. Because of the lack of associated hypoglycemia and selectivity toward decreasing cerebral metabolism, further investigation of ethanol's use as a post-stroke therapy, especially in the context of hyperglycemia, seems warranted.

Reduction of brain edema and expression of aquaporins with acute ethanol treatment after traumatic brain injury

OBJECT

Previous studies have demonstrated that traumatic brain injury (TBI) causes brain edema by allowing excessive water passage through aquaporin (AQP) proteins. To establish the potential neuroprotective properties of ethanol as a post-TBI therapy, in the present study the authors determined the effect of ethanol on brain edema, AQP expression, and functional outcomes in a post-TBI setting.

METHODS

Adult male Sprague-Dawley rats weighing between 425 and 475 g received a closed head TBI in which Maramarou's impact-acceleration method was used. Animals were given a subsequent intraperitoneal injection of 0.5 g/kg or 1.5 g/kg ethanol at 60 minutes post-TBI and were killed 24 hours after TBI. Brains were subsequently examined for edema along with AQP mRNA and protein expression. Additional animals treated with either 0.5 g/kg or 1.5 g/kg ethanol at 60 minutes post-TBI were designated for cognitive and motor testing for 3 weeks.

RESULTS

Ethanol administration post-TBI led to significantly (p < 0.05) lower levels of brain edema as measured by brain water content. This downregulation in brain edema was associated with significantly (p < 0.05) reduced levels of AQP mRNA and protein expression as compared with TBI without treatment. These findings concur with cognitive studies in which ethanol-treated animals exhibited significantly (p < 0.05) faster radial maze completion times. Motor behavioral testing additionally demonstrated significant (p < 0.05) beneficial effects of ethanol, with treated animals displaying improved motor coordination when compared with untreated animals.

CONCLUSIONS

The present findings suggest that acute ethanol administration after a TBI decreases AQP expression, which may lead to reduced cerebral edema. Ethanol-treated animals additionally showed improved cognitive and motor outcomes compared with untreated animals.

Alcohol use at time of injury and survival following traumatic brain injury: results from the National Trauma Data Bank

OBJECTIVE

Premised on biological evidence from animal research, recent clinical studies have, for the most part, concluded that elevated blood alcohol concentration levels are independently associated with higher survival or decreased mortality in patients with moderate to severe traumatic brain injury (TBI). This study aims to provide some counterevidence to this claim and to further future investigations.

METHOD

Incident data were drawn from the largest U.S. trauma registry, the National Trauma Data Bank, for emergency department admission years 2002-2006. TBI was identified according to the National Trauma Data Bank's definition using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM), codes. To eliminate confounding, the exact matching method was used to match alcohol-positive with alcohol-negative incidents on sex, age, race/ethnicity, and facility. Logistic regression compared in-hospital mortality between 44,043 alcohol-positive and 59,817 matched alcohol-negative TBI incidents, with and without causes and intents of TBI and Injury Severity Score as covariates. A sensitivity analysis was performed within a subsample of isolated moderate to severe TBI incidents.

RESULTS

Alcohol use at the time of injury was found to be significantly associated with an increased risk for TBI. Including varied causes and intents of TBI and Injury Severity Score as potential confounders in the regression model explained away the statistical significance of the seemingly protective effect of alcohol against TBI mortality for all TBIs and for isolated moderate to severe TBIs.

CONCLUSIONS

The null finding shows that the purported reduction in TBI mortality attributed to positive blood alcohol likely is attributable to residual confounding. Accordingly, the risk of TBI associated with alcohol use should not be overlooked.

Preventing flow-metabolism uncoupling acutely reduces axonal injury after traumatic brain injury

We have previously presented evidence that the development of secondary traumatic axonal injury is related to the degree of local cerebral blood flow (LCBF) and flow-metabolism uncoupling. We have now tested the hypothesis that augmenting LCBF in the acute stages after brain injury prevents further axonal injury. Data were acquired from rats with or without acetazolamide (ACZ) that was administered immediately following controlled cortical impact injury to increase cortical LCBF. Local cerebral metabolic rate for glucose (LCMRglc) and LCBF measurements were obtained 3 h post-trauma in the same rat via ¹⁸F-fluorodeoxyglucose and ¹⁴C-iodoantipyrine co-registered autoradiographic images, and compared to the density of damaged axonal profiles in adjacent sections, and in additional groups at 24 h used to assess different populations of injured axons stereologically. ACZ treatment significantly and globally elevated LCBF twofold above untreated-injured rats at 3 h (p<0.05), but did not significantly affect LCMRglc. As a result, ipsilateral LCMRglc:LCBF ratios were reduced by twofold to sham-control levels, and the density of β-APP-stained axons at 24 h was significantly reduced in most brain regions compared to the untreated-injured group (p<0.01). Furthermore, early LCBF augmentation prevented the injury-associated increase in the number of stained axons from 3-24 h. Additional robust stereological analysis of impaired axonal transport and neurofilament compaction in the corpus callosum and cingulum underlying the injury core confirmed the amelioration of β-APP axon density, and showed a trend, but no significant effect, on RMO14-positive axons. These data underline the importance of maintaining flow-metabolism coupling immediately after injury in order to prevent further axonal injury, in at least one population of injured axons.

Use-dependent dendritic regrowth is limited after unilateral controlled cortical impact to the forelimb sensorimotor cortex

Compensatory neural plasticity occurs in both hemispheres following unilateral cortical damage incurred by seizures, stroke, and focal lesions. Plasticity is thought to play a role in recovery of function, and is important for the utility of rehabilitation strategies. Such effects have not been well described in models of traumatic brain injury (TBI). We examined changes in immunoreactivity for neural structural and plasticity-relevant proteins in the area surrounding a controlled cortical impact (CCI) to the forelimb sensorimotor cortex (FL-SMC), and in the contralateral homotopic cortex over time (3-28 days). CCI resulted in considerable motor deficits in the forelimb contralateral to injury, and increased reliance on the ipsilateral forelimb. The density of dendritic processes, visualized with immunostaining for microtubule-associated protein-2 (MAP-2), were bilaterally decreased at all time points. Synaptophysin (SYN) immunoreactivity increased transiently in the injured hemisphere, but this reflected an atypical labeling pattern, and it was unchanged in the contralateral hemisphere compared to uninjured controls. The lack of compensatory neuronal structural plasticity in the contralateral homotopic cortex, despite behavioral asymmetries, is in contrast to previous findings in stroke models. In the cortex surrounding the injury (but not the contralateral cortex), decreases in dendrites were accompanied by neurodegeneration, as indicated by Fluoro-Jade B (FJB) staining, and increased expression of the growth-inhibitory protein Nogo-A. These studies indicate that, following unilateral CCI, the cortex undergoes neuronal structural degradation in both hemispheres out to 28 days post-injury, which may be indicative of compromised compensatory plasticity. This is likely to be an important consideration in designing therapeutic strategies aimed at enhancing plasticity following TBI.

Ethanol intoxication is associated with a lower incidence of admission coagulopathy in severe traumatic brain injury patients

The aim of this study was to determine the impact of ethanol (ETOH) on the incidence of severe traumatic brain injury (sTBI)-associated coagulopathy and to examine the effect of ETOH on in-hospital outcomes in patients sustaining sTBI. Patients admitted to the surgical intensive care unit from June 2005 through December 2008 following sTBI, defined as a head Abbreviated Injury Scale (AIS) score ≥3, were retrospectively identified. Patients with a chest, abdomen, or extremity AIS score >3 were excluded to minimize the impact of extracranial injuries. Criteria for sTBI-associated coagulopathy included thrombocytopenia and/or elevated International Normalized Ratio (INR) and/or prolonged activated partial thromboplastin time (aPTT). The incidence of admission coagulopathy, in-hospital complications, and mortality were compared between patients who were ETOH positive [ETOH (+)] and ETOH negative [ETOH (-)]. During the study period, there were 439 patients with ETOH levels available for analysis. Overall, 46.5% (n=204) of these patients were ETOH (+), while 53.5% (n=235) were ETOH (-). Coagulopathy was significantly less frequent in the ETOH (+) patients compared to their ETOH (-) counterparts (5.4% versus 15.3%; adjusted p<0.001). In the forward logistic regression analysis, a positive ETOH level proved to be an independent protective factor for admission coagulopathy [OR (95% CI)=0.24 (0.10,0.54; p=0.001]. ETOH (+) patients had a significantly lower in-hospital mortality rate than ETOH (-) patients [9.8% versus 16.6%; adjusted p=0.011; adjusted OR (95% CI)=0.39 (0.19,0.81)]. For brain-injured patients arriving alive to the hospital, ETOH intoxication is associated with a significantly lower incidence of early coagulopathy and in-hospital mortality. Further research to establish the pathophysiologic mechanisms underlying any potential beneficial effect of ETOH on the coagulation system following sTBI is warranted.

Pathophysiology of sports-related concussion: an update on basic science and translational research

CONTEXT

Concussions that occur during participation in athletic events affect millions of individuals each year. Although our understanding of the pathophysiology of concussion has grown considerably in recent years, much remains to be elucidated. This article reviews basic science and relevant translational clinical research regarding several aspects of concussion.

EVIDENCE ACQUISITION

A literature search was conducted using PubMed from 1966 to 2010, with an emphasis on work published within the past 10 years. Additional articles were identified from the bibliography of recent reviews.

RESULTS

Basic science and clinical data both indicate that there is a period of increased vulnerability to repeated injury following a concussion and that its duration is variable. Growing evidence indicates that postinjury activity is likely to affect recovery from brain injury. Data suggest that long-term sequelae may result from prior concussion-particularly, repeated injuries. The unique aspects of cerebral development may account for differences in the effects of concussion in children and adolescents when compared with adults.

CONCLUSIONS

The available pathophysiologic data from basic science and clinical studies have increased the evidence base for concussion management strategies-the approaches to which may differ between young athletes and adults.

Beneficial effects of sodium or ethyl pyruvate after traumatic brain injury in the rat

Sodium pyruvate (SP) treatment initiated within 5 min post-injury is neuroprotective in a rat model of unilateral cortical contusion injury (CCI). The current studies examined: (1) effects of delayed SP treatments (1000 mg/kg, i.p., at 1, 12 and 24h), (2) effects of single (1h) or multiple (1, 12 and 24h) ethyl pyruvate treatments (EP; at 20 or 40 mg/kg, i.p.), and (3) mechanisms of action for pyruvate effects after CCI. In Experiment 1, both SP and EP treatment(s) significantly reduced the number of dead/dying cells in the ipsilateral hippocampus (dentate hilus+CA3(c) and/or CA3(a-b) regions) at 72 h post-CCI. Pyruvate treatment(s) attenuated CCI-induced reductions of cerebral cytochrome oxidase activity at 7 2h, significantly improving activity in peri-contusional cortex after multiple SP or EP treatments. Optical density measures of ipsilateral CD11b immuno-staining were significantly increased 72 h post-CCI, but these measures of microglia activation were not different from sham injury values in SP and EP groups with three post-CCI treatments. In Experiment 2, three treatments (1, 12 and 24h) of SP (1000 mg/kg) or EP (40 mg/kg) significantly improved recovery of beam-walking and neurological scores in the first 3 weeks after CCI, and EP treatments significantly improved spatial working memory 1 week post-CCI. Ipsilateral CA3(b) neuronal loss, but not cortical tissue loss, was significantly reduced 1 month post-CCI with pyruvate treatments begun 1h post-CCI. Thus, delayed pyruvate treatments after CCI are neuroprotective and improve neurobehavioral recovery; these effects may be mediated by improved metabolism and reduced inflammation.

The influence of alcohol on behavioral recovery after mTBI in mice

In the United States 258,000 people were injured in 2004 in motor vehicle accidents that were caused by drivers under the influence of alcohol. The majority of these drivers were binge drinkers, most notably young people who tend to drink heavily during the weekends, but rarely drink alcohol during the week. Since a large proportion of the injuries involved head injuries, the present study aimed at investigating the influence of binge alcohol drinking on mild traumatic brain injury (mTBI) in an animal model. Mice had access to 0%, 7.5%, 15%, or 30% alcohol solutions for 48 consecutive hours once a week for 4 weeks as the sole source of fluids (the remaining time they drank water). Three experiments were done. For the first one (alcohol-mTBI-alcohol) the animals were subjected to a controlled mTBI injury by applying a closed-head weight drop, or a sham procedure. After the mTBI/sham-mTBI the animals got alcohol and /water for the same regimen for 4 additional weeks. In the second experiment (alcohol only) after the 4 weeks of drinking blood samples were collected, at the same time as the animals that underwent sham-mTBI or mTBI procedures. In the third experiment (mTBI-alcohol) the mice were subjected to mTBI/sham-mTBI without any treatment, and after mTBI they had alcohol for 4 weeks in the same regimen as in the previous experiments. At the end of the pharmacological treatment all animals were assessed using different behavioral tests. mTBI mice exhibited lower memory ability in the Y-maze, higher anxiety in the elevated plus maze, and lower retention in the passive avoidance test than sham-mTBI animals. Alcohol reversed these effects at all doses. The results suggest that alcohol drinking before trauma might have a protective effect on recovery from brain trauma, but not if consumed after the trauma.

Modifiable factors influencing relapses and disability in multiple sclerosis

A growing body of literature indicates that the natural course of multiple sclerosis can be influenced by a number of factors. Strong evidence suggests that relapses can be triggered by infections, the postpartum period and stressful life events. Vaccinations against influenza, hepatitis B and tetanus appear to be safe. Surgery, general and epidural anaesthesia, and physical trauma are not associated with an increased risk of relapses. Factors that have been associated with a reduced relapse rate are pregnancy, exclusive breastfeeding, sunlight exposure and higher vitamin D levels. A number of medications, including hormonal fertility treatment, seem to be able to trigger relapses. Factors that may worsen progression of disability include stressful life events, radiotherapy to the head, low levels of physical activity and low vitamin D levels. Strong evidence suggests that smoking promotes disease progression, both clinically and on brain magnetic resonance imaging. There is no evidence for an increased progression of disability following childbirth in women with multiple sclerosis. Moderate alcohol intake and exercise might have a neuroprotective effect, but this needs to be confirmed.

Isolated severe traumatic brain injuries: association of blood alcohol levels with the severity of injuries and outcomes

BACKGROUND

Traumatic brain injury is a common cause of death after traumatic insults. Alcohol intoxication is a recognized contributor to the occurrence of these injuries. The specific effects of alcohol exposure on injury severity and subsequent outcomes, however, remain controversial. The aim of this study was to investigate the relationship between blood alcohol levels (BAL) and outcomes in patients with isolated severe traumatic brain injuries (sTBI).

METHODS

During the calendar year 2003, as part of a pilot project, the Los Angeles County Department of Health Services obtained routine BAL on all patients transported to any of its 13 trauma centers. This study analyzes the effect of BAL on outcomes in patients with isolated sTBI (head Abbreviated Injury Scale (AIS) score >or=3; extracranial AIS score <3). The Low/No ethanol (ETOH) group included patients with negative or low (<0.08 mg/dL) BAL. Patients with BAL >or=0.08 mg/dL constituted the high ETOH group. Logistic regression was performed to determine whether alcohol levels had an independent association with outcomes.

RESULTS

There were 815 patients with isolated severe head injuries. Overall, 468 patients (57%) constituted the Low/No ETOH group, and 347 (43%) the high ETOH group. Alcohol levels were not significantly associated with severity of injury, hypotension at admission, Glasgow Coma Scale score, incidence of major complications, and intensive care unit or hospital length of stay. However, adjusted mortality was significantly lower in the high ETOH group when compared with the Low/No ETOH (8.9% vs. 17.1%; adjusted odds ratio: 0.60, 95% confidence interval: 0.37-0.96, p = 0.037). In the subgroup of patients with Injury Severity Score >15 the relative risk for mortality in the high ETOH group was significantly lower than in patients with Low/No ETOH. There was also an increased survival with high ETOH in patients with Injury Severity Score >25, but this was not statistically significant.

CONCLUSIONS

Among patients with isolated sTBI, BAL do not seem to be associated with overall injury severity, head injury severity, or the occurrence of major morbidities. Similarly, hospital and intensive care unit lengths are not affected by high admission BAL level. The adjusted overall in-hospital mortality, however, is significantly lower in patients presenting with the high BAL (>or=0.08 g/dL) after isolated sTBI.

Unexpected death following single blow to the orbit

Severe brain injury is rare after assault to the head with a fist. Our patient was a 39-year-old white male who was punched in a parking lot. The subject fell on his right head. He did not lose consciousness. The subject was taken to the hospital. On admission, his blood alcohol concentration was 229 mg/dL. A CT scan of the head showed no injury. He was admitted to the detoxification unit. He became sober, and was seen ambulating at 3:30 am. By 5:20 am, he was unresponsive. A CT scan of the head showed that an epidural hematoma had developed over the right temporal lobe. The hematoma was drained. The patient did not recover. EEG confirmed no cerebral activity. At autopsy, the brain was removed, showing that the central brain was liquefied. The skull demonstrated a hairline fracture of the right temporal bone, corresponding to the impact with the sidewalk. Our patient differs from the typical victim of head trauma from assault in that severe brain injury or death is typically rare in assault. Alcohol is reported sometimes to have a neuroprotective effect in head injury. The present case illustrates an extreme conclusion of an otherwise-routine head trauma.

Brain metabolism is significantly impaired at blood glucose below 6 mM and brain glucose below 1 mM in patients with severe traumatic brain injury

INTRODUCTION

The optimal blood glucose target following severe traumatic brain injury (TBI) must be defined. Cerebral microdialysis was used to investigate the influence of arterial blood and brain glucose on cerebral glucose, lactate, pyruvate, glutamate, and calculated indices of downstream metabolism.

METHODS

In twenty TBI patients, microdialysis catheters inserted in the edematous frontal lobe were dialyzed at 1 microl/min, collecting samples at 60 minute intervals. Occult metabolic alterations were determined by calculating the lactate- pyruvate (L/P), lactate- glucose (L/Glc), and lactate- glutamate (L/Glu) ratios.

RESULTS

Brain glucose was influenced by arterial blood glucose. Elevated L/P and L/Glc were significantly reduced at brain glucose above 1 mM, reaching lowest values at blood and brain glucose levels between 6-9 mM (P < 0.001). Lowest cerebral glutamate was measured at brain glucose 3-5 mM with a significant increase at brain glucose below 3 mM and above 6 mM. While L/Glu was significantly increased at low brain glucose levels, it was significantly decreased at brain glucose above 5 mM (P < 0.001). Insulin administration increased brain glutamate at low brain glucose, but prevented increase in L/Glu.

CONCLUSIONS

Arterial blood glucose levels appear to be optimal at 6-9 mM. While low brain glucose levels below 1 mM are detrimental, elevated brain glucose are to be targeted despite increased brain glutamate at brain glucose >5 mM. Pathogenity of elevated glutamate appears to be relativized by L/Glu and suggests to exclude insulin- induced brain injury.

Serum ethanol levels: predictor of survival after severe traumatic brain injury

BACKGROUND

Recent studies have suggested that moderate doses of ethanol (ETOH) before traumatic brain injury (TBI) may have a neuroprotective role.

OBJECTIVE

: The objective of this study is to investigate the effects of serum ETOH levels on outcomes after TBI. Our hypothesis was that ETOH exposure is associated with improved survival in severe TBI patients and that the serum ETOH levels on admission correlate with survival.

METHODS

All patients sustaining severe TBI (head abbreviated injury score >or=3) admitted to the Surgical Intensive Care Unit at the Los Angeles County + University of Southern California Medical Center from January 2000 to December 2005 who had a serum ETOH level measured on admission were analyzed. Patients were classified into ETOH-positive and ETOH-negative groups, according to the serum ETOH levels and compared for differences in outcomes using logistic regression to adjust for clinically and statistically relevant confounding factors.

RESULTS

During the 5-year study period, 482 severe TBI patients admitted to the Surgical Intensive Care Unit at Los Angeles County + University of Southern California Medical Center had a serum ETOH level measured on admission. A total of 47% of severe TBI patients were tested for ETOH. ETOH levels were positive in 37% (179) and negative in 63% (303) of the TBI patients. The ETOH-positive group had a higher percentage of males (91% vs. 79%, p = 0.001), lower percentage of penetrating injuries (9% vs. 20%, p = 0.002), and lower injury severity score (25.7 +/- 11.5 vs. 28.4 +/- 14.1, p = 0.05). Overall mortality was significantly lower in the ETOH-positive group at 27% versus 40% (odds ratio = 0.55, 95% confidence interval: 0.37-0.82; p = 0.004). This survival benefit remained significant after multivariable analysis (adjusted odds ratio = 0.54, 95% confidence interval: 0.31-0.92; adjusted p = 0.02). The mean serum ETOH level was significantly higher for survivors than for nonsurvivors (0.11 +/- 0.21 vs. 0.05 +/- 0.10, p < 0.001). The serum ETOH levels significantly correlated with the probability of survival (r = 0.21, p < 0.001), but this correlation was not strong as shown by the low r value.

CONCLUSION

The results of this study suggest that elevated ETOH serum levels are independently associated with higher survival in patients with severe traumatic brain injuries. Additional research is required to further investigate the mechanism and potential therapeutic implications of this association.

Voluntary exercise or amphetamine treatment, but not the combination, increases hippocampal brain-derived neurotrophic factor and synapsin I following cortical contusion injury in rats

Prior work has shown that d-amphetamine (AMPH) treatment or voluntary exercise improves cognitive functions after traumatic brain injury (TBI). In addition, voluntary exercise increases levels of brain-derived neurotrophic factor (BDNF). The current study was conducted to determine how AMPH and exercise treatments, either alone or in combination, affect molecular events that may underlie recovery following controlled cortical impact (CCI) injury in rats. We also determined if these treatments reduced injury-induced oxidative stress. Following a CCI or sham injury, rats received AMPH (1 mg/kg/day) or saline treatment via an ALZET pump and were housed with or without access to a running wheel for 7 days. CCI rats ran significantly less than sham controls, but exercise level was not altered by drug treatment. On day 7 the hippocampus ipsilateral to injury was harvested and BDNF, synapsin I and phosphorylated (P) -synapsin I proteins were quantified. Exercise or AMPH alone significantly increased BDNF protein in sham and CCI rats, but this effect was lost with the combined treatment. In sham-injured rats synapsin I increased significantly after AMPH or exercise, but did not increase after combined treatment. Synapsin levels, including the P-synapsin/total synapsin ratio, were reduced from sham controls in the saline-treated CCI groups, with or without exercise. AMPH treatment significantly increased the P-synapsin/total synapsin ratio after CCI, an effect that was attenuated by combining AMPH with exercise. Exercise or AMPH treatment alone significantly decreased hippocampal carbonyl groups on oxidized proteins in the CCI rats, compared with saline-treated sedentary counterparts, but this reduction in a marker of oxidative stress was not found with the combination of exercise and AMPH treatment. These results indicate that, whereas exercise or AMPH treatment alone may induce plasticity and reduce oxidative stress after TBI, combining these treatments may cancel each other's therapeutic effects.

Heterogeneous regional and temporal energetic impairment following controlled cortical impact injury in rats

OBJECTIVES

Following traumatic brain injury metabolic stability is impaired. Duration and reversibility of these changes might be important to guide specific interventions.

METHODS

To characterize temporal and regional changes in cerebral metabolism, 68 male Sprague-Dawley rats were subjected to a focal cortical contusion. Lesion progression and mitochondrial impairment were determined by magnetic resonance imaging (MRI) and triphenyl tetrazolium chloride (TTC) staining, respectively. Metabolic alterations were determined at hours 6 and 24 and day 7 by measuring extracellular glucose, lactate and hypoxanthine levels with microdialysis catheters placed adjacent and distant to the contusion and by quantifying changes in tissue ATP, lactate and glucose using bioluminescence imaging.

RESULTS

The cortical lesion reached its maximal extent at hour 24 and remained confined to the ipsilateral hemisphere. In microdialysate, at hour 6, extracellular hypoxanthine and lactate reached maximal values, thereafter hypoxanthine normalized while lactate remained increased. Extracellular glucose reached the highest values at hour 24 and remained elevated. Bioluminescence imaging revealed heterogeneous changes in areas distant to the contusion. No significant changes were found in ATP content. Slightly elevated tissue glucose until 24 hours in the ipsilateral hemisphere was observed. Following a continuous increase, lactate levels were the highest by 6 hours in the ipsilateral cortex and hippocampus.

DISCUSSION

CCI is associated with disturbances in energetic metabolism. Metabolic perturbation is not restricted to the early phase and the contusional region following focal cortical contusion, but also involves hippocampus and primarily uninjured parts of the hemisphere.

Differential temporal profile of lowered blood glucose levels (3.5 to 6.5 mmol/l versus 5 to 8 mmol/l) in patients with severe traumatic brain injury

INTRODUCTION

Hyperglycaemia is detrimental, but maintaining low blood glucose levels within tight limits is controversial in patients with severe traumatic brain injury, because decreased blood glucose levels can induce and aggravate underlying brain injury.

METHODS

In 228 propensity matched patients (age, sex and injury severity) treated in our intensive care unit (ICU) from 2000 to 2004, we retrospectively evaluated the influence of different predefined blood glucose targets (3.5 to 6.5 versus 5 to 8 mmol/l) on frequency of hypoglycaemic and hyperglycaemic episodes, insulin and norepinephrine requirement, changes in intracranial pressure and cerebral perfusion pressure, mortality and length of stay on the ICU.

RESULTS

Mortality and length of ICU stay were similar in both blood glucose target groups. Blood glucose values below and above the predefined levels were significantly increased in the 3.5 to 6.5 mmol/l group, predominantly during the first week. Insulin and norepinephrine requirements were markedly increased in this group. During the second week, the incidences of intracranial pressure exceeding 20 mmHg and infectious complications were significantly decreased in the 3.5 to 6.5 mmol/l group.

CONCLUSION

Maintaining blood glucose within 5 to 8 mmol/l appears to yield greater benefit during the first week. During the second week, 3.5 to 6.5 mmol/l is associated with beneficial effects in terms of reduced intracranial hypertension and decreased rate of pneumonia, bacteraemia and urinary tract infections. It remains to be determined whether patients might profit from temporally adapted blood glucose limits, inducing lower values during the second week, and whether concomitant glucose infusion to prevent hypoglycaemia is safe in patients with post-traumatic oedema.

The fate of glucose during the period of decreased metabolism after fluid percussion injury: a 13C NMR study

The present study determined the metabolic fate of [1, 2 13C2] glucose in male control rats and in rats with moderate lateral fluid percussion injured (FPI) at 3.5 h and 24 h post-surgery. After a 3-h infusion, the amount of 13C-labeled glucose increased bilaterally (26% in left/injured cerebral cortex and 45% in right cerebral cortex) at 3.5 h after FPI and in injured cortex (45%) at 24 h after injury, indicating an accumulation of unmetabolised glucose not seen in controls. No evidence of an increase in anaerobic glycolysis above control levels was found after FPI, as 13C-labeled lactate tended to decrease at both time points and was significantly reduced (33%) in the injured cortex at 24 h post-FPI. A bilateral decrease in the 13C-labeling of both glutamate and glutamine was observed in the FPI rats at 3.5 h and the glutamine pool remained significantly decreased in the injured cortex at 24 h, suggesting reduced oxidative metabolism in both neuronal and astrocyte compartments after injury. The percentage of glucose metabolism through the pentose phosphate pathway (PPP) increased in the injured (13%) and contralateral (11%) cortex at 3.5 h post-FPI and in the injured cortex (9%) at 24 h post-injury. Based upon the changes in metabolite pools, our results show an injury-induced decrease in glucose utilization and oxidation within the first 24 h after FPI. Increased metabolism through the PPP would result in increased NADPH synthesis, suggesting a need for reducing equivalents after FPI to help restore the intracellular redox state and/or in response to free radical stress.

Glucose metabolism after traumatic brain injury: estimation of pyruvate carboxylase and pyruvate dehydrogenase flux by mass isotopomer analysis

The metabolism of [1, 2 (13)C(2)] glucose via the tricarboxylic acid (TCA) cycle yields a number of key glutamate mass isotopomers whose formation is a function of pyruvate carboxylase (PC) and pyruvate dehydrogenase (PDH). Analysis of the isotopomer distribution patterns was used to determine the relative flux of glucose entry into the TCA cycle through anaplerotic and oxidative pathways in the cerebral cortex of both uninjured and traumatically injured adult male rats. In the cerebral cortex of uninjured animals the PC/PDH ratio showed greater metabolism of glucose via pyruvate carboxylase, which is consistent with the notion that the majority of glucose taken up at rest is used as a substrate for anaplerotic processes and not as an energy source. While traumatic brain injury did not change the overall (13)C enrichment of glutamate indicating a continued oxidation of glucose, the PC/PDH ratio was reduced in the injured cortex at 3.5 h after injury. This suggests that glucose metabolism is primarily directed through pathways associated with energy production in the early postinjury period. By 24 h, the anaplerotic flux decreased and the PC/PDH ratio increased in both the injured and non-injured cortex indicating a switch away from energy production to pathways associated with anabolic and/or regenerative processes.