Category Archives: Brain Trauma

Selective activation of cannabinoid receptor-2 reduces neuroinflammation after traumatic brain injury via alternative macrophage polarization.

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“Inflammation is an important mediator of secondary neurological injury after traumatic brain injury (TBI). Endocannabinoids, endogenously produced arachidonate based lipids, have recently emerged as powerful anti-inflammatory compounds, yet the molecular and cellular mechanisms underlying these effects are poorly defined. Endocannabinoids are physiological ligands for two known cannabinoid receptors, CB1R and CB2R. In the present study, we hypothesized that selective activation of CB2R attenuates neuroinflammation and reduces neurovascular injury after TBI. Taken together, our findings support the development of selective CB2R agonists as a therapeutic strategy to improve TBI outcomes while avoiding the psychoactive effects of CB1R activation.”   https://www.ncbi.nlm.nih.gov/pubmed/29079445   http://www.sciencedirect.com/science/article/pii/S0889159117304774

“The Cannabinoid CB2 Receptor as a Target for Inflammation-Dependent Neurodegeneration. The first approved cannabinoid drugs were analogues of Δ9-tetrahydrocannabinol (Δ9-THC). Dronabinol is a natural isomer of THC that is found in the cannabis plant” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2435344/

“Cannabinoid Receptor CB2 Is Involved in Tetrahydrocannabinol-Induced Anti-Inflammation against Lipopolysaccharide in MG-63 Cells. These results suggested that CB2 is involved in the THC-induced anti-inflammation”  https://www.hindawi.com/journals/mi/2015/362126/

“Cannabinoids as novel anti-inflammatory drugs. Manipulation of endocannabinoids and/or use of exogenous cannabinoids in vivo can constitute a potent treatment modality against inflammatory disorders.  For several centuries, marijuana has been used as an alternative medicine in many cultures and, recently, its beneficial effects have been shown”  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2828614/

“Cannabinoids as neuroprotective agents in traumatic brain injury.  Cannabinoids of all classes have the ability to protect neurons from a variety of insults that are believed to underlie delayed neuronal death after traumatic brain injury (TBI), including excitotoxicity, calcium influx, free radical formation and neuroinflammation.” https://www.ncbi.nlm.nih.gov/pubmed/15281893

“Effect of marijuana use on outcomes in traumatic brain injury. A positive THC screen is associated with decreased mortality in adult patients sustaining TBI.”  https://www.ncbi.nlm.nih.gov/pubmed/25264643

Intra-cerebral cannabidiol infusion-induced neuroprotection is partly associated with the TNF-α/TNFR1/NF-кB pathway in transient focal cerebral ischaemia.

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“Stroke is a neurological disease, which, in addition to high mortality, imposes many financial and mental burdens on families and the society.

The main objective of this study was to investigate the effect of cannabidiol (CBD) on one of the major inflammatory pathways in cerebral ischaemia.

RESULTS:

Administration of CBD (100 and 200 ng/rat) caused a significant reduction in infarction, brain oedema, and BBB permeability compared with the vehicle-received group. Down-regulation of TNF-α, TNFR1, and NF-кB expression was also observed by CBD.

CONCLUSION:

The results achieved in this study support the idea that CBD has a cerebroprotective effect (partly through suppression of TNF-α, TNFR1, and NF-кB) on ischaemic injury.”

https://www.ncbi.nlm.nih.gov/pubmed/28872345

http://www.tandfonline.com/doi/abs/10.1080/02699052.2017.1358397?journalCode=ibij20

Interplay Between n-3 and n-6 Long-Chain Polyunsaturated Fatty Acids and the Endocannabinoid System in Brain Protection and Repair.

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“The brain is enriched in arachidonic acid (ARA) and docosahexaenoic acid (DHA), long-chain polyunsaturated fatty acids (LCPUFAs) of the n-6 and n-3 series, respectively. Both are essential for optimal brain development and function. Dietary enrichment with DHA and other long-chain n-3 PUFA, such as eicosapentaenoic acid (EPA), has shown beneficial effects on learning and memory, neuroinflammatory processes, and synaptic plasticity and neurogenesis. ARA, DHA and EPA are precursors to a diverse repertoire of bioactive lipid mediators, including endocannabinoids.

The endocannabinoid system comprises cannabinoid receptors, their endogenous ligands, the endocannabinoids, and their biosynthetic and degradation enzymes. Anandamide (AEA) and 2-arachidonoylglycerol (2-AG) are the most widely studied endocannabinoids and are both derived from phospholipid-bound ARA. The endocannabinoid system also has well-established roles in neuroinflammation, synaptic plasticity and neurogenesis, suggesting an overlap in the neuroprotective effects observed with these different classes of lipids.

Indeed, growing evidence suggests a complex interplay between n-3 and n-6 LCPUFA and the endocannabinoid system. For example, long-term DHA and EPA supplementation reduces AEA and 2-AG levels, with reciprocal increases in levels of the analogous endocannabinoid-like DHA and EPA-derived molecules. This review summarises current evidence of this interplay and discusses the therapeutic potential for brain protection and repair.”

https://www.ncbi.nlm.nih.gov/pubmed/28875399

https://link.springer.com/article/10.1007%2Fs11745-017-4292-8

“The seed of Cannabis sativa L. has been an important source of nutrition for thousands of years in Old World cultures. Technically a nut, hempseed typically contains over 30% oil and about 25% protein, with considerable amounts of dietary fiber, vitamins and minerals. Hempseed oil is over 80% in polyunsaturated fatty acids (PUFAs), and is an exceptionally rich source of the two essential fatty acids (EFAs) linoleic acid (18:2 omega-6) and alpha-linolenic acid (18:3 omega-3). The omega-6 to omega-3 ratio (n6/n3) in hempseed oil is normally between 2:1 and 3:1, which is considered to be optimal for human health. Hempseed has been used to treat various disorders for thousands of years in traditional oriental medicine.”  http://link.springer.com/article/10.1007%2Fs10681-004-4811-6

Neuroprotection in oxidative stress-related neurodegenerative diseases: role of endocannabinoid system modulation.

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“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 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 Issue: Accumulating recent evidence also suggests that there is an important interplay between the lipid endocannabinoid system (ECS; comprising of 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 in order to modulate redox state-dependent cell death, and to decrease consequent or preceding inflammatory response holds therapeutic potential in 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.”

 https://www.ncbi.nlm.nih.gov/pubmed/28497982

Cannabidiol reduces lung injury induced by hypoxic-ischemic brain damage in newborn piglets.

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“Brain hypoxic-ischemic (HI) damage induces distant inflammatory lung damage in newborn pigs. We aimed to investigate the effects of cannabidiol (CBD) on lung damage in this scenario.

RESULTS:

CBD prevented HI-induced deleterious effects on TLC and OI and reduced lung histological damage, modulating inflammation (decreased leukocyte infiltration and IL-1 concentration) and reducing protein content in BALF and EVLW. These effects were related to CBD-induced anti-inflammatory changes in the brain. HI did not increase oxidative stress in the lungs. In the lungs, WAY100635 blunted CBD’s beneficial effects on histological damage, IL-1 concentration and EVLW.

CONCLUSIONS:

CBD reduced brain HI-induced distant lung damage, with 5-HT1A receptor involvement in these effects. Whether CBD’s effects on lungs were due to anti-inflammatory effects on the brain or to direct effects on lungs remains to be elucidated.” https://www.ncbi.nlm.nih.gov/pubmed/28388598

“Hypoxic-ischemic brain injury is a diagnostic term that encompasses a complex constellation of pathophysiological and molecular injuries to the brain induced by hypoxia, ischemia, cytotoxicity, or combinations of these conditions. The typical causes of hypoxic-ischemic brain injury – cardiac arrest, respiratory arrest, near-drowning, near-hanging, and other forms of incomplete suffocation, carbon monoxide and other poisonous gas exposures, and perinatal asphyxia – expose the entire brain to potentially injurious reductions of oxygen (i.e., hypoxia) and/or diminished blood supply (ischemia).”  http://www.internationalbrain.org/articles/hypoxicischemic-brain-injury/

“Hypoxic-ischemic brain damage induces distant inflammatory lung injury in newborn piglets.” https://www.ncbi.nlm.nih.gov/pubmed/25950454

“Cannabidiol reduces lung injury induced by hypoxic-ischemic brain damage in newborn piglets.” https://www.ncbi.nlm.nih.gov/pubmed/28388598

Neuroprotective effect of WIN55,212-2 against 3-nitropropionic acid-induced toxicity in the rat brain: involvement of CB1 and NMDA receptors.

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“The endocannabinoid system (ECS), and agonists acting on cannabinoid receptors (CBr), are known to regulate several physiological events in the brain, including modulatory actions on excitatory events probably through N-methyl-D-aspartate receptor (NMDAr) activity.

Actually, CBr agonists can be neuroprotective.

Our results demonstrate a protective role of WIN55,212-2 on the 3-NP-induced striatal neurotoxicity that could be partially related to the ECS stimulation and induction of NMDAr hypofunction, representing an effective therapeutic strategy at the experimental level for further studies.”

https://www.ncbi.nlm.nih.gov/pubmed/28337258

Cannabis Use Has Negligible Effects Following Severe Traumatic Injury.

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“Nearly half of all states have legalized medical marijuana or recreational-use marijuana. As more states move toward legalization, the effects on injured patients must be evaluated.

This study sought to determine effects of cannabis positivity at the time of severe injury on hospital outcomes compared with individuals negative for illicit substances and those who were users of other illicit substances.

Cannabis users suffering from severe injury demonstrated no detrimental outcomes in this study compared with nondrug users.”

https://www.ncbi.nlm.nih.gov/pubmed/28272189

Cell-Autonomous Excitation of Midbrain Dopamine Neurons by Endocannabinoid-Dependent Lipid Signaling.

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“The major endocannabinoid in the mammalian brain is the bioactive lipid 2-arachidonoylglycerol (2-AG). The best-known effects of 2-AG are mediated by G-protein-coupled cannabinoid receptors. In principle, 2-AG could modify neuronal excitability by acting directly on ion channels, but such mechanisms are poorly understood.

Using a preparation of dissociated mouse midbrain dopamine neurons to isolate effects on intrinsic excitability, we found that 100 nM 2-AG accelerated pacemaking and steepened the frequency-current relationship for burst-like firing. In voltage-clamp experiments, 2-AG reduced A-type potassium current (IA) through a cannabinoid receptor-independent mechanism mimicked by arachidonic acid, which has no activity on cannabinoid receptors. Activation of orexin, neurotensin, and metabotropic glutamate Gq/11-linked receptors mimicked the effects of exogenous 2-AG and their actions were prevented by inhibiting the 2-AG-synthesizing enzyme diacylglycerol lipase α.

The results show that 2-AG and related lipid signaling molecules can directly tune neuronal excitability in a cell-autonomous manner by modulating IA.”

https://www.ncbi.nlm.nih.gov/pubmed/28262417

Inflammatory Regulation by Driving Microglial M2 Polarization: Neuroprotective Effects of Cannabinoid Receptor-2 Activation in Intracerebral Hemorrhage.

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“The cannabinoid receptor-2 (CB2R) was initially thought to be the “peripheral cannabinoid receptor.” Recent studies, however, have documented CB2R expression in the brain in both glial and neuronal cells, and increasing evidence suggests an important role for CB2R in the central nervous system inflammatory response.

Intracerebral hemorrhage (ICH), which occurs when a diseased cerebral vessel ruptures, accounts for 10-15% of all strokes. Although surgical techniques have significantly advanced in the past two decades, ICH continues to have a high mortality rate.

The aim of this study was to investigate the therapeutic effects of CB2R stimulation in acute phase after experimental ICH in rats and its related mechanisms.

These findings demonstrated that CB2R stimulation significantly protected the brain damage and suppressed neuroinflammation by promoting the acquisition of microglial M2 phenotype in acute stage after ICH.

Taken together, this study provided mechanism insight into neuroprotective effects by CB2R stimulation after ICH.”

 https://www.ncbi.nlm.nih.gov/pubmed/28261199

Endocannabinoids: A Promising Impact for Traumatic Brain Injury.

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“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), CB1and 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.”

 https://www.ncbi.nlm.nih.gov/pubmed/28261100