The Influence of Cannabinoids on Drosophila Behaviors, Longevity, and Traumatic Injury Responses of the Adult Nervous System

Introduction: The legalization of cannabis products has increased their usage in the United States. Among the ∼500 active compounds, this is especially true for cannabidiol (CBD)-based products, which are being used to treat a range of ailments. Research is ongoing regarding the safety, therapeutic potential, and molecular mechanism of cannabinoids. Drosophila (fruit flies) are widely used to model a range of factors that impact neural aging, stress responses, and longevity. Materials and Methods: Adult wild-type Drosophila melanogaster cohorts (w1118/+) were treated with different Δ9-tetrahydrocannabinol (THC) and CBD dosages and examined for neural protective properties using established neural aging and trauma models. The therapeutic potential of each compound was assessed using circadian and locomotor behavioral assays and longevity profiles. Changes to NF-κB pathway activation were assessed by measuring expression levels of downstream targets using quantitative real-time polymerase chain reaction analysis of neural cDNAs. Results: Flies exposed to different CBD or THC dosages showed minimal effects to sleep and circadian-based behaviors or the age-dependent decline in locomotion. The 2-week CBD (3 μM) treatment did significantly enhance longevity. Flies exposed to different CBD and THC dosages were also examined under stress conditions, using the Drosophila mild traumatic brain injury (mTBI) model (10×). Pretreatment with either compound did not alter baseline expression of key inflammatory markers (NF-κB targets), but did reduce neural mRNA profiles at a key 4-h time point following mTBI exposure. Locomotor responses were also significantly improved 1 and 2 weeks following mTBI. After mTBI (10×) exposure, the 48-h mortality rate improved for CBD (3 μM)-treated flies, as were global average longevity profiles for other CBD doses tested. While not significant, THC (0.1 μM)-treated flies show a net positive impact on acute mortality and longevity profiles following mTBI (10×) exposure. Conclusions: This study shows that the CBD and THC dosages examined had at most a modest impact on basal neural function, while demonstrating that CBD treatments had significant neural protective properties for flies following exposure to traumatic injury.

Approaches and reporting of alcohol and other drug testing for injured patients in hospital-based studies: A systematic review

ISSUE

Hospital alcohol and/or other drug (AOD) testing is important for identifying AOD-related injuries; however, testing methods vary. This systematic review aimed to examine biological AOD testing methods from hospital-based studies of injured patients and quantify what proportion reported key information on those testing methods.

APPROACH

Observational studies published in English from 2010 onwards involving biological AOD testing for injured patients presenting to hospital were included. Studies examining single injury causes were excluded. Extracted data included concentration thresholds for AOD detection (e.g., lower limits of detection, author-defined cut-offs), test type (e.g., immunoassay, breathalyser) and approach (e.g., routine, clinical discretion), timing of testing, sample type and the proportion of injured cases tested for AODs.

KEY FINDINGS

Of 83 included studies, 76 measured alcohol and 37 other drugs. Forty-nine studies defined blood alcohol concentration thresholds (ranging from 0 to 0.1 g/100 mL). Seven studies defined concentration thresholds for other drugs. Testing approach was reported in 39/76 alcohol and 18/37 other drug studies. Sample type was commonly reported (alcohol: n = 69/76; other drugs: n = 28/37); alcohol was typically measured using blood (n = 60) and other drugs using urine (n = 20). Studies that reported the proportion of cases tested (alcohol: n = 53/76; other drugs: n = 28/37), reported that between 0% and 89% of cases were not tested for alcohol and 0% and 91% for other drugs. Timing of testing was often unreported (alcohol: n = 61; other drugs: n = 30).

IMPLICATIONS AND CONCLUSION

Variation in AOD testing methods alongside incomplete reporting of those methods limits data comparability and interpretation. Standardised reporting of testing methods will assist AOD-related injury surveillance and prevention.

Traumatic Brain Injury Outcomes After Recreational Cannabis Use

Purpose

Basic science data indicate potential neuroprotective effects of cannabinoids in traumatic brain injury (TBI). We aimed to evaluate the effects of pre-TBI recreational cannabis use on TBI outcomes.

Patients and Methods

We used i2b2 (a scalable informatics framework; www.i2b2.org) to identify all patients presenting with acute TBI between 1/1/2014 and 12/31/2016, then conducted a double-abstraction medical chart review to compile basic demographic, urine drug screen (UDS), Glasgow Coma Scale (GCS), and available outcomes data (mortality, modified Rankin Scale (mRS), duration of stay, disposition (home, skilled nursing facility, inpatient rehabilitation, other)) at discharge and at specific time points thereafter. We conducted multivariable nested ordinal and logistic regression analyses to estimate associations between cannabis use, other UDS results, demographic factors, and selected outcomes.

Results

i2b2 identified 6396 patients who acutely presented to our emergency room with TBI. Of those, 3729 received UDS, with 22.2% of them testing positive for cannabis. Mortality was similar in patients who tested positive vs negative for cannabis (3.9% vs 4.8%; p = 0.3) despite more severe GCS on admission in the cannabis positive group (p = 0.045). Several discharge outcome measures favored the cannabis positive group who had a higher rate of discharge home vs other care settings (p < 0.001), lower discharge mRS (p < 0.001), and shorter duration of hospital stay (p < 0.001) than the UDS negative group. Multivariable analyses confirmed mostly independent associations between positive cannabis screen and these post-TBI short- and long-term outcomes.

Conclusion

This study adds evidence about the potentially neuroprotective effects of recreational cannabis for short- and long-term post-TBI outcomes. These results need to be confirmed via prospective data collections.

Cannabis use disorders and outcome of admission to intensive care: A retrospective multi-centre cohort study

PURPOSE

To identify factors associated with cannabinoid use among patients admitted to ICU and its impact on survival.

METHODS

A cohort of adult patients admitted to four public Australian ICUs was assembled. Individuals with mental and behavioural disorders related to cannabinoids were identified using ICD10-AM codes.

RESULTS

Of a cohort of 34,680 admissions among 28,689 adults, 292 (0.8%) had an associated diagnosis related to cannabinoids, of which 66% were classified as harmful use, 26% as dependence syndrome/withdrawal state, 4% as psychosis/delirium, and 4% as acute intoxication. Patients with cannabinoid-use disorders were more likely to be male (73%), tended to be younger (36 vs 62 years), with fewer comorbidities and lesser severity of disease. ICU LOS was longer for those with cannabinoid-use disorders (2 vs 1 days; p < 0.0001). Patients with cannabinoid-use disorders had lower 90-day case-fatality (6% vs. 10%; p = 0.034), however no significant effect on mortality was present after adjustment for severity of illness, age, and chronic comorbidities (p = 1.0).

CONCLUSION

Cannabinoid-use disorders were present in 0.8% of ICU admissions in our region and were associated with increased ICU length of stay. Further studies are needed to examine cannabinoids as contributors to and modifiers of critical illness.

Prevalence of Alcohol and Other Drug Use in Patients Presenting to Hospital for Violence-Related Injuries: A Systematic Review

Substance use is a risk factor for being both a perpetrator and a victim of violence. The aim of this systematic review was to report the prevalence of acute pre-injury substance use in patients with violence-related injuries. Systematic searches were used to identify observational studies that included patients aged ≥15 years presenting to hospital after violence-related injuries and used objective toxicology measures to report prevalence of acute pre-injury substance use. Studies were grouped based on injury cause (any violence-related, assault, firearm, and other penetrating injuries including stab and incised wounds) and substance type (any substance, alcohol only, drugs other than alcohol only), and they were summarized using narrative synthesis and meta-analyses. This review included 28 studies. Alcohol was detected in 13%-66% of any violence-related injuries (five studies), 4%-71% of assaults (13 studies), 21%-45% of firearm injuries (six studies; pooled estimate = 41%, 95% CI: 40%-42%, n = 9,190), and 9%-66% of other penetrating injuries (nine studies; pooled estimate = 60%, 95% CI: 56%-64%, n = 6,950). Drugs other than alcohol were detected in 37% of any violence-related injuries (one study), 39% of firearm injuries (one study), 7%-49% of assaults (five studies), and 5%-66% of penetrating injuries (three studies). The prevalence of any substance varied across injury categories: any violence-related injuries = 76%-77% (three studies), assaults = 40%-73% (six studies), firearms = n/a, other penetrating injuries = 26%-45% (four studies; pooled estimate = 30%, 95% CI: 24%-37%, n = 319).Overall, substance use was frequently detected in patients presenting to hospital for violence-related injuries. Quantification of substance use in violence-related injuries provides a benchmark for harm reduction and injury prevention strategies.

Cannabis use in the intensive care setting: A scoping review

PURPOSE

Cannabis is the most used recreational drug worldwide, and is increasingly used for medicinal purposes, however little is known about its impact on patients in intensive care units (ICU). Our objective was to identify key themes in the literature surrounding cannabis in the ICU and identify future research priorities.

METHODS

Four databases were systematically searched for literature investigating the impact of cannabis, and evidence for its therapeutic use, in adult ICU patients.

RESULTS

Of 2589 articles screened, 22 articles were included for analysis. Cannabis-associated admissions were primarily related to an outbreak of vaping associated lung injury, and synthetic cannabinoid toxicity. Studies on the impact of cannabis use on outcomes were mostly limited to trauma and burns populations, with an inconsistent mortality benefit, and a trend towards increased pain scores and analgesic requirements found. There is minimal research on its therapeutic uses in ICU, with two trials investigating the use of a synthetic cannabinoid in patients with severe traumatic brain injury, with ultimately no significant effect on intracranial pressure found.

CONCLUSIONS

There is a paucity of studies investigating the impact of cannabinoids or their therapeutic uses in critically ill patients, with further research in this area needed.

The modulatory role of cannabis use in subconcussive neural injury

Cannabis use has become popular among athletes, many of whom are exposed to repetitive subconcussive head impacts. We aimed to test whether chronic cannabis use would be neuroprotective or exacerbating against acute subconcussive head impacts. This trial included 43 adult soccer players (Cannabis group using cannabis at least once a week for the past 6 months, n = 24; non-cannabis control group, n = 19). Twenty soccer headings, induced by our controlled heading model, significantly impaired ocular-motor function, but the degrees of impairments were less in the cannabis group compared to controls. The control group significantly increased its serum S100B level after heading, whereas no change was observed in the cannabis group. There was no group difference in serum neurofilament light levels at any time point. Our data suggest that chronic cannabis use may be associated with an enhancement of oculomotor functional resiliency and suppression of the neuroinflammatory response following 20 soccer headings.

Cannabinoids in traumatic brain injury and related neuropathologies: preclinical and clinical research on endogenous, plant-derived, and synthetic compounds

Traumatic brain injury is common, and often results in debilitating consequences. Even mild traumatic brain injury leaves approximately 20% of patients with symptoms that persist for months. Despite great clinical need there are currently no approved pharmaceutical interventions that improve outcomes after traumatic brain injury. Increased understanding of the endocannabinoid system in health and disease has accompanied growing evidence for therapeutic benefits of Cannabis sativa. This has driven research of Cannabis' active chemical constituents (phytocannabinoids), alongside endogenous and synthetic counterparts, collectively known as cannabinoids. Also of therapeutic interest are other Cannabis constituents, such as terpenes. Cannabinoids interact with neurons, microglia, and astrocytes, and exert anti-inflammatory and neuroprotective effects which are highly desirable for the management of traumatic brain injury. In this review, we comprehensively appraised the relevant scientific literature, where major and minor phytocannabinoids, terpenes, synthetic cannabinoids, and endogenous cannabinoids were assessed in TBI, or other neurological conditions with pathology and symptomology relevant to TBI, as well as recent studies in preclinical TBI models and clinical TBI populations.

Recovery from Traumatic Brain Injury Following Treatment with Δ9-Tetrahydrocannabinol Is Associated with Increased Expression of Granulocyte-Colony Stimulating Factor and Other Neurotrophic Factors

Introduction: The hematopoietic cytokine granulocyte-colony stimulating factor (G-CSF) is well known to stimulate proliferation of blood stem/progenitor cells of the leukocyte lineage, but is also recognized as a neurotrophic factor involved in brain self-repair processes. G-CSF administration has been shown to promote recovery from experimental models of traumatic brain injury (TBI) and to modulate components of the endocannabinoid system (eCS). Conversely, Δ9-tetrahydrocannabinol (Δ9THC) treatment of normal mice has been shown to increase blood levels of G-CSF in the periphery. Hypothesis: Administration of the phytocannabinoid Δ9THC will enhance brain repair following controlled cortical impact (CCI) by upregulating G-CSF and other neurotrophic factors (brain-derived neurotrophic factor [BDNF] and glial-derived neurotrophic factor [GDNF]) in brain regions. Materials and Methods: C57BL/6J mice underwent CCI and were treated for 3 days with THC 3 mg/kg intraperitoneally. Motor function on a rotarod was recorded at baseline and 3, 7, and 14 days after CCI. Groups of mice were euthanized at 7 and 14 days. G-CSF, BDNF, and GDNF expression were measured at 7 and 14 days in cerebral cortex, striatum, and hippocampus on the side of the trauma. Results: Δ9THC-treated mice ran on the rotarod longer than vehicle-treated mice and recovered to normal rotarod performance levels at 2 weeks. These mice, compared to vehicle-treated animals, exhibited significant upregulation of G-CSF as well as BDNF and GDNF in cerebral cortex, striatum, and hippocampus. Conclusion: Administration of the phytocannabinoid Δ9THC promotes significant recovery from TBI and is associated with upregulation of brain G-CSF, BDNF, and GDNF, neurotrophic factors previously shown to mediate brain self-repair following TBI and stroke.

The Impact of Isolated Baseline Cannabis Use on Outcomes Following Thoracolumbar Spinal Fusion: A Propensity Score-Matched Analysis

BACKGROUND

There is limited literature evaluating the impact of isolated cannabis use on outcomes for patients following spinal surgery. This study sought to compare 90-day complication, 90-day readmission, as well as 2-year revision rates between baseline cannabis users and non-users following thoracolumbar spinal fusion (TLF) for adult spinal deformity (ASD).

METHODS

The New York Statewide Planning and Research Cooperative System (SPARCS) database was queried between January 2009 and September 2013 to identify all patients who underwent TLF for ASD. Inclusion criteria were age ≥18 years and either minimum 90-day (for complications and readmissions) or 2-year (for revisions) follow-up surveillance. Cohorts were created and propensity score-matched based on presence or absence of isolated baseline cannabis use. Baseline demographics, hospital-related parameters, 90-day complications and readmissions, and two-year revisions were retrieved. Multivariate binary stepwise logistic regression identified independent outcome predictors.

RESULTS

704 patients were identified (n=352 each), with comparable age, sex, race, primary insurance, Charlson/Deyo scores, surgical approach, and levels fused between cohorts (all, p>0.05). Cannabis users (versus non-users) incurred lower 90-day overall and medical complication rates (2.4% vs. 4.8%, p=0.013; 2.0% vs. 4.1%, p=0.018). Cohorts had otherwise comparable complication, revision, and readmission rates (p>0.05). Baseline cannabis use was associated with a lower risk of 90-day medical complications (OR=0.47, p=0.005). Isolated baseline cannabis use was not associated with 90-day surgical complications and readmissions, or two-year revisions.

CONCLUSION

Isolated baseline cannabis use, in the absence of any other diagnosed substance abuse disorders, was not associated with increased odds of 90-day surgical complications or readmissions or two-year revisions, though its use was associated with reduced odds of 90-day medical complications when compared to non-users undergoing TLF for ASD. Further investigations are warranted to identify the physiologic mechanisms underlying these findings. Level of Evidence: III.

Prevalence of alcohol and other drug use in patients presenting to hospital for fall-related injuries: a systematic review

BACKGROUND

Alcohol and other drug (AOD) use is a key preventable risk factor for serious injuries. Prevention strategies to date have largely focused on transport injuries, despite AOD use being a significant risk factor for other injury causes, including falls. This systematic review aimed to report the prevalence of AOD use in patients presenting to hospital for fall-related injuries.

METHODS

This systematic review includes studies published in English after the year 2010 that objectively measured the prevalence of AOD use in patients presenting to hospital for a fall-related injury. Screening, data extraction and risk of bias assessments were completed by two independent reviewers. Data were presented using narrative synthesis and, where appropriate, meta-analyses.

RESULTS

A total of 12 707 records were screened. Full texts were retrieved for 2042 records, of which 29 were included. Four studies reported the combined prevalence of any alcohol and/or drug use, generating a pooled prevalence estimate of 37% (95% CI 25% to 49%). Twenty-two records reported on the prevalence of acute alcohol use alone and nine reported specifically on the prevalence of drugs other than alcohol, with prevalence ranging from 2% to 57% and 7% to 46%, respectively. The variation in prevalence estimates likely resulted from differences in toxicology testing methods across studies.

CONCLUSIONS

AOD exposure was common in hospitalised fall-related injuries. However, research addressing prevalence across different types of falls and the use of drugs other than alcohol was limited. Future research should address these areas to improve our understanding of which populations should be targeted in AOD and injury prevention strategies .

PROSPERO REGISTRATION NUMBER

CRD42020188746.

Phosphatidylethanolamine Deficiency and Triglyceride Overload in Perilesional Cortex Contribute to Non-Goal-Directed Hyperactivity after Traumatic Brain Injury in Mice

Traumatic brain injury (TBI) is often complicated by long-lasting disabilities, including headache, fatigue, insomnia, hyperactivity, and cognitive deficits. In a previous study in mice, we showed that persistent non-goal-directed hyperactivity is a characteristic post-TBI behavior that was associated with low levels of endocannabinoids in the perilesional cortex. We now analyzed lipidome patterns in the brain and plasma in TBI versus sham mice in association with key behavioral parameters and endocannabinoids. Lipidome profiles in the plasma and subcortical ipsilateral and contralateral brain were astonishingly equal in sham and TBI mice, but the ipsilateral perilesional cortex revealed a strong increase in neutral lipids represented by 30 species of triacylglycerols (TGs) of different chain lengths and saturation. The accumulation of TG was localized predominantly to perilesional border cells as revealed by Oil Red O staining. In addition, hexosylceramides (HexCer) and phosphatidylethanolamines (PE and ether-linked PE-O) were reduced. They are precursors of gangliosides and endocannabinoids, respectively. High TG, low HexCer, and low PE/PE-O showed a linear association with non-goal-directed nighttime hyperactivity but not with the loss of avoidance memory. The analyses suggest that TG overload and HexCer and PE deficiencies contributed to behavioral dimensions of post-TBI psychopathology.

Title: Marijuana Use Associated with Decreased Mortality in Trauma Patients

BACKGROUND

The incidence of trauma patients with a positive marijuana screen (pMS) is increasing but the effects of marijuana on outcomes have varied in previous studies. A recent statewide analysis demonstrated decreased mortality for intensive care unit (ICU) trauma patients with pMS. Thus, we hypothesized a pMS to be associated with a decreased risk of mortality for all trauma patients.

METHODS

The 2017 Trauma Quality Improvement Program (TQIP) database was queried for adult (≥18 years-old) pMS patients, who were compared to patients negative for all drugs and alcohol (nDS). Patients not drug tested or testing positive for drug(s)/alcohol other than marijuana were excluded. Multivariable logistic regression was used to evaluate risk of mortality after controlling for known predictors of mortality including age, sex, injury severity, vital signs, and comorbidities. Additional subgroup analyses were performed for ICU patients and younger adults (<40 years-old).

RESULTS

From 141 737 tested patients, 23 310 (16.4%) had an isolated pMS. Patients with pMS were younger (P < .001) but had a similar median injury severity score (ISS) (9, P = .42) compared to nDS patients. On multivariable analysis the associated risk of mortality was lower for pMS (OR .79, .71-.87, P < .001) compared to nDS patients. Subgroups analyses also demonstrated decreased associated risk of mortality for ICU and younger patients (both P < .05).

DISCUSSION

Patients with a pMS had decreased associated risk of mortality compared to nDS patients, including subgroups of ICU and younger patients. These findings require corroboration with future prospective clinical study and basic science evaluation to ascertain the exact pathophysiologic basis and thereby target potential interventions.

The changing landscape of the use of medical marijuana after traumatic brain injury: a narrative review

OBJECTIVE

To summarize the potential therapeutic benefits of medical marijuana for patients with traumatic brain injury (TBI).

METHODS

A systematic search was conducted using PubMed and Cochran's library for information regard the safety and efficacy of medical marijuana as a therapeutic agent. We investigated, in depth, articles specifically evaluating medical marijuana's use in TBI, as well as articles that summarized the effects of marijuana in general. Articles from the year 2000-2020 were included.

RESULTS

A total of 37 articles met our inclusion criteria. An additional 3 articles were obtained from reference lists.

CONCLUSION

Studies have shown that medical marijuana can potentially aid the recovery from TBI by modulating the endocannabinoid system, reducing inflammation and secondary injury. Adverse cognitive and physiological effects have been observed in the acute setting as well as chronically, though more research is necessitated. There is also the concern of significant drug-drug interactions that have not been thoroughly studied. Thus, while there is evidence that medical marijuana can be beneficial in the treatment of TBI, more research is necessitated to fully explore the long-term efficacy and adverse effects.

Cannabidiol (CBD) and cognition in epilepsy

Anecdotal reports of the benefits of cannabis and its components in the treatment of epilepsy have been reported for millennia. However, only recently randomized controlled trial data in support of cannabidiol (CBD) became available resulting in its FDA approval for the treatment of seizures and epilepsy. One of the most common and debilitating comorbidities of epilepsy is cognitive impairment. This impairment has a multifactorial etiology including network dysfunction due to seizures, negative cognitive side effects from anti-seizure medications (ASMs), and mood disturbances. Knowing the effects of a particular ASM (either positive or negative) is vital for providers to counsel patients on expected side effects, and may result in choosing a particular regimen over the other if the patient already suffers from significant cognitive deficits. Unlike most other ASMs and other well-studied cannabinoids such as Δ9-tetrahydrocannabinol, CBD has been shown to have additional mechanisms of action (MOA) that result in neuroprotective, anti-inflammatory, anti-oxidant, and neurogenesis effects. These additional MOAs suggest that the use of CBD could lead to other actions including positive effects on cognition that may be independent of seizure control. This targeted review discusses the currently available data on CBD's effects on cognition in epilepsy. First, we review the proposed mechanisms by which CBD could exert effects on cognition. Then, we present the pre-clinical/animal data investigating cognitive effects of CBD in seizure/epilepsy models. Finally, we discuss the available human data, including the studies in people with epilepsy that included cognitive evaluations pre- and on-CBD, and studies investigating if CBD has any effects on brain structure or function in areas pertinent to memory and cognitive functions.

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.

Relationship of Time of Injury Marijuana Exposure and Traumatic Brain Injury: A Systematic Review

BACKGROUND

Traumatic brain injury (TBI) is a significant nursing concern, as it is a leading cause of mortality, morbidity, and disability in the United States. Notably, up to 51% of all TBI patients have substance use exposure at the time of injury. Marijuana remains the most widely used illicit drug in the United States. However, little is known about marijuana exposure and TBI incidence and severity, particularly at the time of injury.

METHODS

A systematic literature review was conducted following PRISMA guidelines in PubMed to determine the relationship between marijuana exposure and TBI severity.Heterogeneity of study designs, concepts, samples, and variables in included studies precluded a meta-analysis. Hence, a descriptive analysis of findings was conducted.

RESULTS

The search yielded 939 studies, of which eight met inclusion criteria. Only one study found a connection between positive marijuana toxicology screen and mortality outcomes in TBI patients. There was significant variation in how marijuana exposure was defined, conceptualized, and operationalized in the other studies.

CONCLUSIONS

This review identified the need for larger, better-designed studies to address the significant knowledge gap about the relationship between marijuana use and its influence on TBI. Data and knowledge derived from such studies can help inform policy and aid in the development of nursing interventions that target prevention and increase awareness of TBI risk when under the influence of marijuana.

Psychedelics for Brain Injury: A Mini-Review

Objective: Stroke and traumatic brain injury (TBI) are among the leading causes of disability. Even after engaging in rehabilitation, nearly half of patients with severe TBI requiring hospitalization are left with major disability. Despite decades of investigation, pharmacologic treatment of brain injury is still a field in its infancy. Recent clinical trials have begun into the use of psychedelic therapeutics for treatment of brain injury. This brief review aims to summarize the current state of the science's relevance to neurorehabilitation, and may act as a resource for those seeking to understand the precedence for these ongoing clinical trials.

Methods: Narrative mini-review of studies published related to psychedelic therapeutics and brain injury.

Results: Recent in vitro, in vivo, and case report studies suggest psychedelic pharmacotherapies may influence the future of brain injury treatment through modulation of neuroinflammation, hippocampal neurogenesis, neuroplasticity, and brain complexity.

Conclusions: Historical data on the safety of some of these substances could serve in effect as phase 0 and phase I studies. Further phase II trials will illuminate how these drugs may treat brain injury, particularly TBI and reperfusion injury from stroke.

Impact of opioid use disorder on resource utilization and readmissions after operative trauma

BACKGROUND

Although patients with opioid use disorder have been shown to be more susceptible to traumatic injury, the impact of opioid use disorder after trauma-related admission remains poorly characterized. The present nationally representative study evaluated the association of opioid use disorder on clinical outcomes after traumatic injury warranting operative intervention.

METHODS

The 2010 to 2018 Nationwide Readmissions Database was used to identify adult trauma victims who underwent major operative procedures. Injury severity was quantified using International Classification of Diseases Trauma Mortality Prediction Model. Entropy balancing was used to adjust for intergroup differences. Multivariable regression models were developed to assess the association of opioid use disorder on in-hospital mortality, perioperative complications, resource utilization, and readmissions.

RESULTS

Of an estimated 5,089,003 hospitalizations, 54,097 (1.06%) had a diagnosis of opioid use disorder with increasing prevalence during the study period. Compared with others, opioid use disorder had a lower proportion of extremity injuries and falls but greater predicted mortality measured by Trauma Mortality Prediction Model. After adjustment, opioid use disorder was associated with decreased odds of in-hospital mortality (adjusted odds ratio: 0.61; 95% confidence interval, 0.53-0.70) but had greater likelihood of pneumonia, infectious complications, and acute kidney injury. Additionally, opioid use disorder was associated with longer hospitalization duration as well as greater index costs and risk of readmission within 30 days (adjusted odds ratio: 1.36; 95% confidence interval, 1.25-1.49).

CONCLUSION

Opioid use disorder in operative trauma has significantly increased in prevalence and is associated with decreased in-hospital index mortality but greater resource utilization and readmission.

Medicinal Applications of Cannabinoids Extracted from Cannabis sativa (L.): A New Route in the Fight Against COVID-19?

Cannabis sativa is a well-known plant that has been recognized for its benefits since ancient times by several medicinal systems, including those of China, India, Greece, and Egypt. Although C. sativa is one of the most investigated medicinal plants in the world, it faces some of the greatest controversies surrounding its legalization and use as a medication. C. sativa contains several hundred phytoconstituents, including the infamous "cannabinoids". It is necessary to properly understand the medicinal importance of these phytochemicals and spread awareness among the countries where cannabis is still facing legal obstacles. The current review focuses on the most recent literature pertaining to various applications of cannabinoids, with a special focus on the medicinal aspect of these phytochemicals. Peer-reviewed articles focusing on the importance of cannabis and cannabinoids are the target of this review. Articles were selected based on the relevance to the general scope of the work, i.e., application of cannabinoids. Cannabinoids can truly be regarded as wonder drugs, considering their immense diversity of usage. Unfortunately, however, many of the mares have never been researched biologically or pharmacologically due to their low yield in the plant. However, the approval of some cannabinoids by the FDA (along with other recognized national medical health systems) has opened the horizon for the use of these natural drugs in medicines such as Epidiolex® (cannabidiol, used for the treatment of severe forms of epilepsy) and Sativex®(Δ⁹-tetrahydrocannabinol and cannabidiol, used for the treatment of spasticity caused by multiple sclerosis). Many pharmacological properties of C. sativa are attributed to cannabidiol (CBD), a non-psychoactive component, along with Δ9-tetrahydrocannabinol (Δ⁹-THC), a psychoactive component. This review addresses the most important applications or current utilization of cannabinoids in a variety of treatments such as chronic pain, cancer, emesis, anorexia, irritable bowel syndrome, communicable diseases, glaucoma, and central nervous system disorders. The biosynthetic pathway of cannabinoids is also discussed. In short, cannabis has a myriad of bioactive compounds that have the potential to increase the list of approved cannabinoids suitable for therapy.

Use of Medical Cannabis to Treat Traumatic Brain Injury

There is not a single pharmacological agent with demonstrated therapeutic efficacy for traumatic brain injury (TBI). With recent legalization efforts and the growing popularity of medical cannabis, patients with TBI will inevitably consider medical cannabis as a treatment option. Pre-clinical TBI research suggests that cannabinoids have neuroprotective and psychotherapeutic properties. In contrast, recreational cannabis use has consistently shown to have detrimental effects. Our review identified a paucity of high-quality studies examining the beneficial and adverse effects of medical cannabis on TBI, with only a single phase III randomized control trial. However, observational studies demonstrate that TBI patients are using medical and recreational cannabis to treat their symptoms, highlighting inconsistencies between public policy, perception of potential efficacy, and the dearth of empirical evidence. We conclude that randomized controlled trials and prospective studies with appropriate control groups are necessary to fully understand the efficacy and potential adverse effects of medical cannabis for TBI.

The combined effects of alcohol and marijuana use prior to traumatic brain injury on mortality

Background

Alcohol (ETOH) intoxication is a common comorbidity in traumatic brain injury (TBI), and marijuana (THC) has been implicated as a major risk factor for trauma. The objective this study was to investigate the combined effects of ETOH and THC on mortality after TBI.

Materials and methods

A retrospective review of patient data was performed to assess adult (>18 years) patients with brain injuries between January 2012 and December 2018. Included patients sustained TBI (Abbreviated Injury Scale (AIS 1-6)) and were divided into two groups: No Substances and THC + ETOH.

Results

1085 (median age 52 years [range: 18–97 years]; 33.5% female (364/1085)) patients met the inclusion criteria. Significant differences for mortality at discharge were found between groups (p = 0.0025) with higher mortality in the No Substances group. On multiple logistic regression, a positive test for both ETOH + THC was found not to independently predict mortality at discharge, while age, Glasgow Coma Scale, intensive care unit stay, Injury Severity Score, length of hospital stay, and days on ventilator were independent predictors.

Conclusions

After controlling for confounding variables, positive ETOH + THC screens were not found to be independent predictors of mortality at discharge. Therefore, our results indicated no survival benefit for TBI patients with concomitant ETOH and THC use prior to injury.

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No survival benefit of alcohol and marijuana for all traumatic brain injury levels

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Glasgow Coma Scale predicts mortality for all traumatic brain injury levels

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Length of stay predicts mortality for all traumatic brain injury levels

Traumatic brain injury and the misuse of alcohol, opioids, and cannabis

Traumatic brain injury (TBI), most often classified as concussion, is caused by biomechanical forces to the brain resulting in short- or long-term impairment in brain function. TBI resulting from military combat, sports, violence, falls, and vehicular accidents is a major cause of long-term physical, cognitive, and psychiatric dysfunction. Psychiatric disorders associated with TBI include depression, anxiety, and substance use disorder, all having significant implications for post-TBI recovery and rehabilitation. This chapter reviews the current preclinical and clinical literature describing the bidirectional relationship between TBI and misuse of three commonly abused drugs: alcohol, opioids, and cannabis. We highlight the influence of each of these drugs on the incidence of TBI, as well as trends in their use after TBI. Furthermore, we discuss factors that may underlie post-injury substance use. Understanding the complex relationship between TBI and substance misuse will enhance the clinical treatment of individuals suffering from these two highly comorbid conditions.

Understanding Cannabis-Based Therapeutics in Sports Medicine

CONTEXT

With increased use of cannabis-based products by the public for both recreational and medical use, sports medicine clinicians should be informed of historical context, current legal considerations, and existing evidence with regard to efficacy, safety, and risks in the athletic community.

EVIDENCE ACQUISITION

A review of ClinicalTrials.gov, MEDLINE, and CINAHL from 2015 to present was conducted with emphasis on the most recent literature using search terms, cannabis, nabiximols, cannabinoids, pain management, THC, CBD, and marijuana. Bibliographies based on original search were utilized to pursue further literature search.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 3.

RESULTS

At present, limited high-quality studies exist for use of cannabinoids for acute pain, chronic pain, or concussion. None of the trials involving cannabinoids included the athletic population. Thus, results from this clinical review are extrapolated to conditions of the sports medicine population. For acute pain, 2 small-randomized double-blinded crossover trials concluded no immediate effect of cannabinoid therapy. More robust evidence exists for treatment of chronic pain conditions through meta-analysis and systemic reviews. Cannabinoid therapy exhibits moderate efficacy as a treatment for some chronic pain conditions. Investigations included a broad spectrum of chronic pain conditions, including neuropathic, musculoskeletal, inflammatory, and central pain conditions, and reveal reduction in pain and improvement of quality of life with limited adverse effects. For concussion, evidence is based on preclinical in vitro and animal models revealing possible neuroprotective effects as well as 2 clinical studies involving the presence of cannabinoids for concussion (some sports-related), but there are no high-quality trials evaluating efficacy for treatment with cannabinoids at this time.

CONCLUSION

Although various biochemical explanations exist on the use of cannabinoid therapy through modulation of the endocannabinoid system for several medical issues affecting athletes, recommendations from clinicians must be extrapolated from a majority of research done in the nonathletic population. Lack of strong-quality clinical evidence, coupled with inconsistent federal and state law as well as purity issues with cannabis-based products, make it difficult for the sports medicine clinician to widely recommend cannabinoid therapeutics at present. Future larger, higher quality clinical research studies with standardized pure extracts will better guide appropriate medical use going forward. At present, evidence for a multitude of therapeutic applications is emerging for cannabinoid treatment approaches. With emphasis placed on patient-centered clinical decisions, cannabinoids hold promise of treatment for athletes with chronic pain conditions. Clinicians who treat the athletic community must consider legal and ethical issues when discussing and recommending the use of cannabinoids, with acknowledgment of inconsistencies in purity of various formulations and concerns of drug testing.

Low brain endocannabinoids associated with persistent non-goal directed nighttime hyperactivity after traumatic brain injury in mice

Traumatic brain injury (TBI) is a frequent cause of chronic headache, fatigue, insomnia, hyperactivity, memory deficits, irritability and posttraumatic stress disorder. Recent evidence suggests beneficial effects of pro-cannabinoid treatments. We assessed in mice levels of endocannabinoids in association with the occurrence and persistence of comparable sequelae after controlled cortical impact in mice using a set of long-term behavioral observations in IntelliCages, motor and nociception tests in two sequential cohorts of TBI/sham mice. TBI mice maintained lower body weights, and they had persistent low levels of brain ethanolamide endocannabinoids (eCBs: AEA, OEA, PEA) in perilesional and subcortical ipsilateral brain tissue (6 months), but rapidly recovered motor functions (within days), and average nociceptive responses were within normal limits, albeit with high variability, ranging from loss of thermal sensation to hypersensitivity. TBI mice showed persistent non-goal directed nighttime hyperactivity, i.e. they visited rewarding and non-rewarding operant corners with high frequency and random success. On successful visits, they made more licks than sham mice resulting in net over-licking. The lower the eCBs the stronger was the hyperactivity. In reward-based learning and reversal learning tasks, TBI mice were not inferior to sham mice, but avoidance memory was less stable. Hence, the major late behavioral TBI phenotype was non-goal directed nighttime hyperactivity and "over-licking" in association with low ipsilateral brain eCBs. The behavioral phenotype would agree with a "post-TBI hyperactivity disorder". The association with persistently low eCBs in perilesional and subcortical regions suggests that eCB deficiency contribute to the post-TBI psychopathology.

The effects of alcohol and marijuana on survival after severe traumatic brain injury: A retrospective cohort study

Background

Alcohol (ETOH) and marijuana (THC) use have previously shown to improve outcomes after Traumatic Brain Injury (TBI). However, whether TBI severity impacts outcomes among patients tested positive for both ETOH and THC remains unclear.

Materials and methods

A retrospective review from the Northern Ohio Regional Trauma Registry, which includes deidentified data from six regional hospitals, including three Level 1 and three Level 3 trauma centers, was performed to assess adult (>18 years) patients with severe TBI (head Abbreviated Injury Score ≥ 3) between January 2012 and December 2018 having an alcohol and drug toxicology screen and data regarding outcome at discharge. Patients were divided into two groups: 1) patients with a negative ETOH and drug test, and 2) patients positive for ETOH + THC. Mortality at discharge was the primary outcome measure and multiple logistic regression was used to assess predictors of mortality at discharge.

Results

A total of 854 (median age: 51 years [range: 18–72]; 34.4% female [294/854]) patients were included. On multiple logistic regression, age (p = 0.003), days in intensive care unit (ICU) (p < 0.001), Glasgow Coma Scale (GCS) (p < 0.001), Injury Severity Score (ISS) (p < 0.001), length of stay (LOS) (p < 0.001), and days on ventilator support (p = 0.032) were significant predictors of mortality at discharge. Blood alcohol content (BAC), cause of TBI, drug class, and sex were not significant predictors of mortality at discharge.

Conclusions

After severe TBI, positive THC and BAC screening did not predict mortality at discharge after controlling for confounding variables, indicating no survival benefit for patients with severe TBI.

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No survival benefit of alcohol and marijuana for severe traumatic brain injury.

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Glasgow Coma Scale predict mortality for severe traumatic brain injury.

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Injury Severity Score predict mortality for severe traumatic brain injury.

Targeting the endocannabinoid system: a predictive, preventive, and personalized medicine-directed approach to the management of brain pathologies

Cannabis-inspired medical products are garnering increasing attention from the scientific community, general public, and health policy makers. A plethora of scientific literature demonstrates intricate engagement of the endocannabinoid system with human immunology, psychology, developmental processes, neuronal plasticity, signal transduction, and metabolic regulation. Despite the therapeutic potential, the adverse psychoactive effects and historical stigma, cannabinoids have limited widespread clinical application. Therefore, it is plausible to weigh carefully the beneficial effects of cannabinoids against the potential adverse impacts for every individual. This is where the concept of "personalized medicine" as a promising approach for disease prediction and prevention may take into the account. The goal of this review is to provide an outline of the endocannabinoid system, including endocannabinoid metabolizing pathways, and will progress to a more in-depth discussion of the therapeutic interventions by endocannabinoids in various neurological disorders.

Cannabis Use and Sport: A Systematic Review

CONTEXT

Cannabis use has increased, in large part due to decriminalization. Despite this increase in usage, it remains unclear what proportion of athletes use cannabis and what effect it has on athletic performance and recovery.

OBJECTIVE

To systematically review cannabis use among athletes, including epidemiology, effect on performance and recovery, and regulations for use in sport.

DATA SOURCES

PubMed, MEDLINE, and EMBASE databases were queried from database inception through November 15, 2018. A hand search of policies, official documents, and media reports was performed for relevant information.

STUDY SELECTION

All studies related to cannabis use in athletes, including impact on athletic performance or recovery, were included.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Demographic and descriptive data of included studies relating to epidemiology of cannabis use in athletes were extracted and presented in weighted means or percentages where applicable.

RESULTS

Overall, 37 studies were included, of which the majority were cross-sectional studies of elite and university athletes. Among 11 studies reporting use among athletes (n = 46,202), approximately 23.4% of respondents reported using cannabis in the past 12 months. Two studies found a negative impact on performance, while another 2 studies found no impact. There was no literature on the influence of cannabis on athletic recovery. Across athletic organizations and leagues, there is considerable variability in acceptable thresholds for urine tetrahydrocannabinol levels (>15 to 150 ng/mL) and penalties for athletes found to be above these accepted thresholds.

CONCLUSION

Overall, these results suggest that approximately 1 in 4 athletes report using cannabis within the past year. Based on the available evidence, cannabis does not appear to positively affect performance, but the literature surrounding this is generally poor. Given the variability in regulation across different sport types and competition levels, as well as the growing number of states legalizing recreational cannabis use, there is a need to improve our understanding of the effects of cannabis use on the athlete and perhaps adopt a clearer and overarching policy for the use of cannabis by athletes in all sports and at all levels.

Cannabis, alcohol and cigarette use during the acute post-concussion period

Objective: To document the prevalence of acute post-concussion cannabis, alcohol and cigarette use and their association with clinical recovery and symptom burden.Methods: A prospective cohort study was conducted. Concussions were physician-diagnosed and presented to the emergency department and concussion clinic within 7 days post-injury. Participants were assessed weekly and followed for a minimum 4 weeks. A survival analysis (using physician-determined recovery to both cognitive and physical activities) in addition to a weekly symptom score analysis was conducted.Results: A total of 307 acute concussions with a mean age of 33.7 years (SD, 13.0) were included. Acute post-concussion cannabis, alcohol and cigarette use were identified in 43 (14.0%), 125 (40.7%) and 61 (19.9%) individuals. Acute cannabis, alcohol and cigarette use were not associated with recovery to cognitive (p > .05) or physical activity (p > .05). Acute cigarette use was associated with a higher unadjusted symptom severity score at week1 (p = .003). Acute cannabis use was associated with lower symptom severity scores at week-3 (p = .061) and week-4 (p = .029).Conclusion: In conclusion, cannabis, alcohol and cigarette use were prevalent in the acute period post-concussion; however, were not observed to impact recovery within the first 4 weeks post-injury. Amongst unrecovered individuals, acute cannabis use was associated with lower symptom burden, while cigarette use was associated with greater initial symptom burden.

Cerebral Microvascular Injury: A Potentially Treatable Endophenotype of Traumatic Brain Injury-Induced Neurodegeneration

Traumatic brain injury (TBI) is one the most common human afflictions, contributing to long-term disability in survivors. Emerging data indicate that functional improvement or deterioration can occur years after TBI. In this regard, TBI is recognized as risk factor for late-life neurodegenerative disorders. TBI encompasses a heterogeneous disease process in which diverse injury subtypes and multiple molecular mechanisms overlap. To develop precision medicine approaches where specific pathobiological processes are targeted by mechanistically appropriate therapies, techniques to identify and measure these subtypes are needed. Traumatic microvascular injury is a common but relatively understudied TBI endophenotype. In this review, we describe evidence of microvascular dysfunction in human and animal TBI, explore the role of vascular dysfunction in neurodegenerative disease, and discuss potential opportunities for vascular-directed therapies in ameliorating TBI-related neurodegeneration. We discuss the therapeutic potential of vascular-directed therapies in TBI and the use and limitations of preclinical models to explore these therapies.

Medicinal Properties of Cannabinoids, Terpenes, and Flavonoids in Cannabis, and Benefits in Migraine, Headache, and Pain: An Update on Current Evidence and Cannabis Science

BACKGROUND

Comprehensive literature reviews of historical perspectives and evidence supporting cannabis/cannabinoids in the treatment of pain, including migraine and headache, with associated neurobiological mechanisms of pain modulation have been well described. Most of the existing literature reports on the cannabinoids Δ⁹ -tetrahydrocannabinol (THC) and cannabidiol (CBD), or cannabis in general. There are many cannabis strains that vary widely in the composition of cannabinoids, terpenes, flavonoids, and other compounds. These components work synergistically to produce wide variations in benefits, side effects, and strain characteristics. Knowledge of the individual medicinal properties of the cannabinoids, terpenes, and flavonoids is necessary to cross-breed strains to obtain optimal standardized synergistic compositions. This will enable targeting individual symptoms and/or diseases, including migraine, headache, and pain.

OBJECTIVE

Review the medical literature for the use of cannabis/cannabinoids in the treatment of migraine, headache, facial pain, and other chronic pain syndromes, and for supporting evidence of a potential role in combatting the opioid epidemic. Review the medical literature involving major and minor cannabinoids, primary and secondary terpenes, and flavonoids that underlie the synergistic entourage effects of cannabis. Summarize the individual medicinal benefits of these substances, including analgesic and anti-inflammatory properties.

CONCLUSION

There is accumulating evidence for various therapeutic benefits of cannabis/cannabinoids, especially in the treatment of pain, which may also apply to the treatment of migraine and headache. There is also supporting evidence that cannabis may assist in opioid detoxification and weaning, thus making it a potential weapon in battling the opioid epidemic. Cannabis science is a rapidly evolving medical sector and industry with increasingly regulated production standards. Further research is anticipated to optimize breeding of strain-specific synergistic ratios of cannabinoids, terpenes, and other phytochemicals for predictable user effects, characteristics, and improved symptom and disease-targeted therapies.

A cross-sectional examination of choice and behavior of veterans with access to free medicinal cannabis

Background: With a rise in public pressure to increase veteran access to medicinal cannabis, free cannabis collectives for military veterans are proliferating across the US. Objectives: The aim of the current study was to document which cannabis formulations and routes of administration are chosen by veterans with increased access to cannabis, and to determine whether cannabis is being used as a substitute for other licit and illicit drugs. Method: The current study collected cross-sectional self-report data on cannabis use, cannabinoid constituent composition, primary indication of use, and substitution practices among a sample of 93 US military veterans (84.9% male) with access to free cannabis. Result: Most of the sample reported using cannabinoids as a substitute for either alcohol, tobacco, prescription medications, or illicit substances, reported that they use cannabis frequently (Modal frequency >4x/day, Modal quantity = 5 to 8 grams/week), and primarily select higher-risk cannabis formulations (i.e., high THC/low CBD, smoked). The majority of the sample reported that they use cannabis to self-treat multiple physical and mental health conditions/symptoms. Conclusions: Results of the current study suggest that military Veterans with reduced barriers to access cannabis could be making both helpful and harmful choices regarding their cannabis use. These findings suggest that more guidance on the selection of cannabis-based products in this population is warranted, particularly as barriers to medicinal cannabis access are reduced.

Cannabis Use is Associated with Increased Mechanical Ventilation and Polysubstance Use in Trauma Patients

Recent policy changes in California regarding cannabis use underscore the need to study outcomes and prevalence of this drug in trauma. Our study aims to study the prevalence of cannabis use and associations with injury types and outcomes in Los Angeles County trauma patients. Data were reviewed from 21,276 adult patients from a Los Angeles countywide database spanning five years (2012–2016), who underwent urine toxicology testing in the ED after sustaining a traumatic injury. The percentage of trauma patients using marijuana increased from 36 to 43 per cent over the five-year period. On univariate analysis, cannabis-positive patients were significantly younger and more likely male, with lower median systolic blood pressure and heart rate on arrival in the ED. A higher proportion of cannabis users had penetrating trauma, and 48 per cent of cannabis users also tested positive for amphetamines, cocaine, opioids, or Phencyclidine. On multivariate analysis, cannabis was associated with an increase in need for mechanical ventilation after adjusting for age, admission Glasgow Coma Score, gender, polysubstance use, blunt or penetrating mechanism, and Injury Severity Score, and was not associated with increases in mortality or ICU length of stay.

Neuroprotection in Oxidative Stress-Related Neurodegenerative Diseases: Role of Endocannabinoid System Modulation

SIGNIFICANCE

Redox imbalance may lead to overproduction of reactive oxygen and nitrogen species (ROS/RNS) and subsequent oxidative tissue damage, which is a critical event in the course of neurodegenerative diseases. It is still not fully elucidated, however, whether oxidative stress is the primary trigger or a consequence in the process of neurodegeneration. Recent Advances: Increasing evidence suggests that oxidative stress is involved in the propagation of neuronal injury and consequent inflammatory response, which in concert promote development of pathological alterations characteristic of most common neurodegenerative diseases.

CRITICAL ISSUES

Accumulating recent evidence also suggests that there is an important interplay between the lipid endocannabinoid system [ECS; comprising the main cannabinoid 1 and 2 receptors (CB1 and CB2), endocannabinoids, and their synthetic and metabolizing enzymes] and various key inflammatory and redox-dependent processes.

FUTURE DIRECTIONS

Targeting the ECS to modulate redox state-dependent cell death and to decrease consequent or preceding inflammatory response holds therapeutic potential in a multitude of oxidative stress-related acute or chronic neurodegenerative disorders from stroke and traumatic brain injury to Alzheimer's and Parkinson's diseases and multiple sclerosis, just to name a few, which will be discussed in this overview. Antioxid. Redox Signal. 29, 75-108.

Marijuana use and mortality following orthopedic surgical procedures

Background: The association between marijuana use and surgical procedures is a matter of increasing societal relevance that has not been well studied in the literature. The primary aim of this study is to evaluate the relationship between marijuana use and in-hospital mortality, as well as to assess associated comorbidities in patients undergoing commonly billed orthopedic surgeries. Methods: The National Inpatient Sample (NIS) database from 2010 to 2014 was used to determine the odds ratios for the associations between marijuana use and in-hospital mortality, heart failure (HF), stroke, and cardiac disease (CD) in patients undergoing 5 common orthopedic procedures: total hip (THA), total knee (TKA), and total shoulder (TSA) arthroplasties, spinal fusion, and traumatic femur fracture fixation. Results: Of 9,561,963 patients who underwent one of the 5 selected procedures in the 4-year period, 26,416 (0.28%) were identified with a diagnosis of marijuana use disorder. In hip and knee arthroplasty patients, marijuana use was associated with decreased odds of mortality compared with no marijuana use (P < .0001) and increased odds of HF (P = .018), stroke (P = .0068), and CD (P = .0123). Traumatic femur fixation patients had the highest prevalence of marijuana use (0.70%), which was associated with decreased odds of mortality (P = .0483), HF (P = .0076), and CD (P = .0003). For spinal fusions, marijuana use was associated with increased odds of stroke (P < .0001) and CD (P < .0001). Marijuana use in patients undergoing total shoulder arthroplasty was associated with decreased odds of mortality (P < .001) and stroke (P < .001). Conclusions: In this study, marijuana use was associated with decreased mortality in patients undergoing THA, TKA, TSA, and traumatic femur fixation, although the significance of these findings remains unclear. More research is needed to provide insight into these associations in a growing surgical population.

Endocannabinoids: A Promising Impact for Traumatic Brain Injury

The endogenous cannabinoid (endocannabinoid) system regulates a diverse array of physiological processes and unsurprisingly possesses considerable potential targets for the potential treatment of numerous disease states, including two receptors (i.e., CB1 and CB2 receptors) and enzymes regulating their endogenous ligands N-arachidonoylethanolamine (anandamide) and 2-arachidonyl glycerol (2-AG). Increases in brain levels of endocannabinoids to pathogenic events suggest this system plays a role in compensatory repair mechanisms. Traumatic brain injury (TBI) pathology remains mostly refractory to currently available drugs, perhaps due to its heterogeneous nature in etiology, clinical presentation, and severity. Here, we review pre-clinical studies assessing the therapeutic potential of cannabinoids and manipulations of the endocannabinoid system to ameliorate TBI pathology. Specifically, manipulations of endocannabinoid degradative enzymes (e.g., fatty acid amide hydrolase, monoacylglycerol lipase, and α/β-hydrolase domain-6), CB1 and CB2 receptors, and their endogenous ligands have shown promise in modulating cellular and molecular hallmarks of TBI pathology such as; cell death, excitotoxicity, neuroinflammation, cerebrovascular breakdown, and cell structure and remodeling. TBI-induced behavioral deficits, such as learning and memory, neurological motor impairments, post-traumatic convulsions or seizures, and anxiety also respond to manipulations of the endocannabinoid system. As such, the endocannabinoid system possesses potential drugable receptor and enzyme targets for the treatment of diverse TBI pathology. Yet, full characterization of TBI-induced changes in endocannabinoid ligands, enzymes, and receptor populations will be important to understand that role this system plays in TBI pathology. Promising classes of compounds, such as the plant-derived phytocannabinoids, synthetic cannabinoids, and endocannabinoids, as well as their non-cannabinoid receptor targets, such as TRPV1 receptors, represent important areas of basic research and potential therapeutic interest to treat TBI.

Pharmacologic Neuroprotection for Functional Outcomes After Traumatic Brain Injury: A Systematic Review of the Clinical Literature

INTRODUCTION

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. The deleterious effects of secondary brain injury may be attenuated by early pharmacological therapy in the emergency room and intensive care unit (ICU). Current medical management of acute TBI is primarily supportive, aimed at reducing intracranial pressure (ICP) and optimizing cerebral perfusion. There are no pharmacological therapies to date that have been unequivocally demonstrated to improve neurological outcomes after TBI.

OBJECTIVES

The purpose of this systematic review was to evaluate the recent clinical studies from January 2013 through November 2015 that investigated neuroprotective functional outcomes of pharmacological agents after TBI.

METHODS

The following databases were searched for relevant studies: MEDLINE (OvidSP January Week 1, 2013-November Week 2 2015), Embase (OvidSP 2013 January 1-2015 November 24), and the unindexed material in PubMed (National Library of Medicine/National Institutes of Health [NLM/NIH]). This systematic review included only full-length clinical studies and case series that included at least five patients and were published in the English language. Only studies that examined functional clinical outcomes were included.

RESULTS

Twenty-five of 527 studies met our inclusion criteria, which investigated 15 independent pharmacological therapies. Eight of these therapies demonstrated possible neuroprotective properties and improved functional outcomes, of which five were investigated with randomized clinical trials: statins, N-acetyl cysteine (NAC), Enzogenol, Cerebrolysin, and nitric oxide synthase inhibitor (VAS203). Three pharmacological agents did not demonstrate neuroprotective effects, and four agents had mixed results.

CONCLUSIONS

While there is currently no single pharmacological therapy that will unequivocally improve clinical outcomes after TBI, several agents have demonstrated promising clinical benefits for specific TBI patients and should be investigated further.

Cannabinoid receptor 1 ligands revisited: Pharmacological assessment in the ACTOne system

In vitro cannabinoid pharmacology has evolved over time from simple receptor binding to include [(35)S]GTPγ, β-arrestin, and cAMP assays. Each assay has benefits and drawbacks; however, no single functional system has been used for high-throughput evaluation of compounds from binding to pharmacological functionality and antagonist assessment in a well-characterized human cell line. In this study, we evaluated and validated one system-ACTOne human embryonic kidney cells transfected with a cyclic nucleotide gated channel and cannabinoid receptor 1 (CB1)-and compared human CB1 affinity, functional, and antagonistic effects on cAMP with previously published results. The study was conducted on a diverse group of CB1 ligands, including endocannabinoids and related compounds, 2-AG, AEA, MAEA, and ACEA, the phytocannabinoid Δ(9) THC, and synthetic cannabinoids CP 55,940, WIN 55,212-2, SR 141716A, CP 945,598, and WIN 55,212-3. Our results were compared with literature values where human CB1 was used for affinity determination and cAMP was used as a functional readout. Here we report the first detailed evaluation of the ACTOne assay for the pharmacological evaluation of CB1 ligands. The results from the study reveal some interesting deviations from previously reported functional activities of the aforementioned ligands.

Neuroprotection in Experimental Autoimmune Encephalomyelitis and Progressive Multiple Sclerosis by Cannabis-Based Cannabinoids

Multiple sclerosis (MS) is the major immune-mediated, demyelinating, neurodegenerative disease of the central nervous system. Compounds within cannabis, notably Δ9-tetrahydrocannabinol (Δ9-THC) can limit the inappropriate neurotransmissions that cause MS-related problems and medicinal cannabis is now licenced for the treatment of MS symptoms. However, the biology indicates that the endocannabinoid system may offer the potential to control other aspects of disease. Although there is limited evidence that the cannabinoids from cannabis are having significant immunosuppressive activities that will influence relapsing autoimmunity, we and others can experimentally demonstrate that they may limit neurodegeneration that drives progressive disability. Here we show that synthetic cannabidiol can slow down the accumulation of disability from the inflammatory penumbra during relapsing experimental autoimmune encephalomyelitis (EAE) in ABH mice, possibly via blockade of voltage-gated sodium channels. In addition, whilst non-sedating doses of Δ9-THC do not inhibit relapsing autoimmunity, they dose-dependently inhibit the accumulation of disability during EAE. They also appear to slow down clinical progression during MS in humans. Although a 3 year, phase III clinical trial did not detect a beneficial effect of oral Δ9-THC in progressive MS, a planned subgroup analysis of people with less disability who progressed more rapidly, demonstrated a significant slowing of progression by oral Δ9-THC compared to placebo. Whilst this may support the experimental and biological evidence for a neuroprotective effect by the endocannabinoid system in MS, it remains to be established whether this will be formally demonstrated in further trials of Δ9-THC/cannabis in progressive MS.