Impact of the Presence of Alcohol at the Time of Injury on Acute and One-Year Cognitive and Functional Recovery After Traumatic Brain Injury

Dentate Gyrus Proliferative Responses After Traumatic Brain Injury and Binge Alcohol in Adult Rats

BACKGROUND

Traumatic brain injury is a significant public health issue that results in serious disability in survivors. Traumatic brain injury patients are often intoxicated with alcohol when admitted to the hospital; however, it is not clear how acute intoxication affects recovery from a traumatic brain injury. Our group has previously shown that binge alcohol prior to traumatic brain injury resulted in long-term impairment in a fine sensorimotor task that was correlated with a decreased proliferative and neuroblast response from the subventricular zone. However, whether binge alcohol prior to traumatic brain injury affects the proliferative response in the hippocampal dentate gyrus is not yet known.

METHODS

Male rats underwent binge alcohol (3 g/kg/day) by gastric gavage for 3 days prior to traumatic brain injury. Cell proliferation was labeled by BrdU injections following traumatic brain injury. Stereological quantification and immunofluorescence confocal analysis of BrdU+ cells in the hippocampal dorsal dentate gyrus was performed at 24 hours, 1 week and 6 weeks post traumatic brain injury.

RESULTS

We found that either traumatic brain injury alone or binge alcohol alone significantly increased dentate gyrus proliferation at 24 hours and 1 week. However, a combined binge alcohol and traumatic brain injury regimen resulted in decreased dentate gyrus proliferation at 24 hours post-traumatic brain injury. At the 6 week time point, binge alcohol overall reduced the number of BrdU+ cells. Furthermore, more BrdU+ cells were found in the dentate hilar region of alcohol traumatic brain injury compared to vehicle traumatic brain injury groups. The location and double-labeling of these mismigrated BrdU+ cells was consistent with hilar ectopic granule cells.

CONCLUSION

The results from this study showed that pre-traumatic brain injury binge alcohol impacts the injury-induced proliferative response in the dentate gyrus in the short-term and may affect the distribution of newly generated cells in the dentate gyrus in the long-term.

Epidemiology of Comorbid Conditions Among Adults 50 Years and Older With Traumatic Brain Injury

OBJECTIVES

Aging individuals with traumatic brain injury (TBI) experience multiple comorbidities that can affect recovery from injury. The objective of this study was to describe the most commonly co-occurring comorbid conditions among adults 50 years and older with TBI.

SETTING

Level I Trauma centers.

PARTICIPANTS

Adults 50 years and older with moderate/severe TBI enrolled in the TBI-Model Systems (TBI-MS) from 2007 to 2014 (n = 2134).

DESIGN

A TBI-MS prospective cohort study.

MAIN MEASURES

International Classification of Disease-9th Revision codes collapsed into 45 comorbidity categories. Comorbidity prevalence estimates and trend analyses were conducted by age strata (50-54, 55-64, 65-74, 75-84, ≥85 years). A dimension reduction method, Treelet Transform, classified clusters of comorbidities that tended to co-occur.

RESULTS

The 3 most commonly occurring comorbid categories were hypertensive disease (52.6/100 persons), other diseases of the respiratory system (51.8/100 persons), and fluid component imbalances (43.7/100 persons). Treelet Transform classified 3 clusters of comorbid codes, broadly classified as (1) acute medical diseases/infections, (2) chronic conditions, and (3) substance abuse disorders.

CONCLUSION

This study provides valuable insight into comorbid conditions that co-occur among adults 50 years and older with TBI and provides a foundation for future studies to explore how specific comorbidities affect TBI recovery.

Subventricular zone neural precursor cell responses after traumatic brain injury and binge alcohol in male rats

Traumatic brain injury (TBI) is a major cause of disability worldwide. Additionally, many TBI patients are intoxicated with alcohol at the time of injury, but the impact of acute intoxication on recovery from brain injury is not well understood. We have previously found that binge alcohol prior to TBI impairs spontaneous functional sensorimotor recovery. However, whether alcohol administration in this setting affects reactive neurogenesis after TBI is not known. This study, therefore, sought to determine the short- and long-term effects of pre-TBI binge alcohol on neural precursor cell responses in the subventricular zone (SVZ) following brain injury in male rats. We found that TBI alone significantly increased proliferation in the SVZ as early as 24 hr after injury. Surprisingly, binge alcohol alone also significantly increased proliferation in the SVZ after 24 hr. However, a combined binge alcohol and TBI regimen resulted in decreased TBI-induced proliferation in the SVZ at 24 hr and 1 week post-TBI. Furthermore, at 6 weeks after TBI, binge alcohol administered at the time of TBI significantly decreased the TBI-induced neuroblast response in the SVZ and the rostral migratory stream (RMS). The results from this study suggest that pre-TBI binge alcohol negatively impacts reparative processes in the brain by decreasing short-term neural precursor cell proliferative responses as well as long-term neuroblasts in the SVZ and RMS.

The Neuroprotective Effect of Ethanol Intoxication in Traumatic Brain Injury Is Associated with the Suppression of ErbB Signaling in Parvalbumin-Positive Interneurons

Ethanol intoxication (EI) is a frequent comorbidity of traumatic brain injury (TBI), but the impact of EI on TBI pathogenic cascades and prognosis is unclear. Although clinical evidence suggests that EI may have neuroprotective effects, experimental support is, to date, inconclusive. We aimed at elucidating the impact of EI on TBI-associated neurological deficits, signaling pathways, and pathogenic cascades in order to identify new modifiers of TBI pathophysiology. We have shown that ethanol administration (5 g/kg) before trauma enhances behavioral recovery in a weight-drop TBI model. Neuronal survival in the injured somatosensory cortex was also enhanced by EI. We have used phospho-receptor tyrosine kinase (RTK) arrays to screen the impact of ethanol on TBI-induced activation of RTK in somatosensory cortex, identifying ErbB2/ErbB3 among the RTKs activated by TBI and suppressed by ethanol. Phosphorylation of ErbB2/3/4 RTKs were upregulated in vGlut2⁺ excitatory synapses in the injured cortex, including excitatory synapses located on parvalbumin (PV)-positive interneurons. Administration of selective ErbB inhibitors was able to recapitulate, to a significant extent, the neuroprotective effects of ethanol both in sensorimotor performance and structural integrity. Further, suppression of PV interneurons in somatosensory cortex before TBI, by engineered receptors with orthogonal pharmacology, could mimic the beneficial effects of ErbB inhibitors. Thus, we have shown that EI interferes with TBI-induced pathogenic cascades at multiple levels, with one prominent pathway, involving ErbB-dependent modulation of PV interneurons.

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.

Unintentional injuries after TBI: Potential risk factors, impacts, and prevention

BACKGROUND

The top three causes of fatal unintentional injuries are falls, motor vehicle crashes, and being struck against or struck by objects or persons. These etiologies also happen to be the leading causes of TBI, a serious public health problem, in the US. Reduced cognitive functioning, poor decision making, increased risk taking, disinhibition, diminished safety skills and substance use, place individuals with TBI at an increased risk for subsequent unintentional injuries. The caregiving, psychological, social and financial burden of initial injuries is enormous. Unintentional injuries post-TBI add to that burden significantly. Many unintentional injuries can be prevented with simple education and environment and lifestyle changes. Injury prevention requires collaboration among many.

OBJECTIVE

This literature review will share information regarding potential triggers or causes of unintentional injuries after TBI to identify potential issues. The many impacts of these injuries will be reviewed. Best practices in prevention will be presented.

CONCLUSION

Ultimately, education, discussion, and awareness across multiple stakeholders can aid in preventing unintentional injuries after TBI.

Alcohol Consumption Does not Impede Recovery from Mild to Moderate Traumatic Brain Injury

OBJECTIVES

To examine the effect of pre-injury alcohol use, acute alcohol intoxication, and post-injury alcohol use on outcome from mild to moderate traumatic brain injury (TBI).

METHODS

Prospective inception cohort of patients who presented to the Emergency Department with mild to moderate TBI and had a blood alcohol level (BAL) taken for clinical purposes. Those who completed the 1-year outcome assessment were eligible for this study (N=91). Outcomes of interest were the count of post-concussion symptoms (British Columbia Post-Concussion Symptom Inventory), low neuropsychological test scores (Neuropsychological Assessment Battery), and abnormal regions of interest on diffusion tensor imaging (low fractional anisotropy). The main predictors were pre-injury alcohol consumption (Cognitive Lifetime Drinking History interview), BAL, and post-injury alcohol use.

RESULTS

The alcohol use variables were moderately to strongly inter-correlated. None of the alcohol use variables (whether continuous or categorical) were related to 1-year TBI outcomes in generalized linear modeling. Participants in this cohort generally had a good clinical outcome, regardless of their pre-, peri-, and post-injury alcohol use.

CONCLUSIONS

Alcohol may not significantly alter long-term outcome from mild to moderate TBI. (JINS, 2016, 22, 816-827).

Alcohol Intake and Reduced Mortality in Patients with Traumatic Brain Injury

BACKGROUND

The purpose of our study was to determine whether alcohol intake influences short-term mortality in patients with traumatic brain injury (TBI), using a comprehensive trauma database.

METHODS

We collected data from 7 emergency departments (EDs) between June 1, 2008 and May 31, 2010, using the same data form. Cases were included if they met the following criteria: (i) older than 15 and (ii) injuries including TBI. Demographics and outcomes were compared between patients with and without alcohol intake. We present the risk of mortality using hazard ratios and 95% confidence intervals.

RESULTS

A total of 76,596 trauma patients visited the EDs during the study period; 12,980 patients were older than 15 and had TBI. There were 4,009 (30.9%) patients in the alcohol-intake group, of whom 3,306 (82.5%) patients were male, 1,450 (36.2%) patients were moved by ambulance, and 1,218 (30.4%) patients' injuries were intentional. The most frequent injury mechanism was falling down with alcohol intake and blunt injury without alcohol intake. Mortality rate was 1.0% with alcohol intake and 2.0% without alcohol intake. After adjusting for all factors related to mortality, the hazard ratio of mortality was 0.72 in the alcohol-intake group.

CONCLUSIONS

Mortality rate due to TBI in the alcohol-intake group appears to be lower compared to that in the no-alcohol-intake group after adjusting for main confounding variables.

Managing behavioral health needs of veterans with traumatic brain injury (TBI) in primary care

Traumatic brain injury (TBI) is a frequent occurrence in the United States, and has been given particular attention in the veteran population. Recent accounts have estimated TBI incidence rates as high as 20 % among US veterans who served in Afghanistan or Iraq, and many of these veterans experience a host of co-morbid concerns, including psychiatric complaints (such as depression and post-traumatic stress disorder), sleep disturbance, and substance abuse which may warrant referral to behavioral health specialists working in primary care settings. This paper reviews many common behavioral health concerns co-morbid with TBI, and suggests areas in which behavioral health specialists may assess, intervene, and help to facilitate holistic patient care beyond the acute phase of injury. The primary focus is on sequelae common to mild and moderate TBI which may more readily present in primary care clinics.