Surprising outcomes in cannabinoid CB1/CB2 receptor double knockout mice in two models of ischemia.

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“Although the number of individuals suffering from stroke in the United States and worldwide will continue to grow, therapeutic intervention for treatment following stroke remains frustratingly limited.

Both the cannabinoid 1 receptor (CB1R) and the cannabinoid 2 receptor (CB2R) have been studied in relationship to stroke. Deletion of the CB2R has been shown to worsen outcome, while selective CB2R agonists have been demonstrated to be neuroprotective following stroke.

We tested the hypothesis that CB1/CB2 receptor double knockout would produce significant increases in infarct size and volume and significant worsening in clinical score, using two mouse models, one of permanent ischemia and one of ischemia/reperfusion.

The results surprisingly revealed that CB1/CB2 double knockout mice showed improved outcomes, with the most improvements in the mouse model of permanent ischemia.

Although initial studies of CB1R knockout mice demonstrated increased injury following stroke, indicating that activation of the CB1R was neuroprotective, later studies of selective antagonists of the CB1R also demonstrated a protective effect.

Surprisingly the double knockout animals had improved outcome.

Since the phenotype of the double knockout is not dramatically changed, significant changes in the contribution of other homeostatic pathways in compensation for the loss of these two important receptors may explain these apparently contradictory results.”

https://www.ncbi.nlm.nih.gov/pubmed/29288767

http://www.sciencedirect.com/science/article/pii/S002432051730677X

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Translating Endocannabinoid Biology into Clinical Practice: Cannabidiol for Stroke Prevention.

Mary Ann Liebert, Inc. publishers

“Introduction: The endocannabinoid system (ECS) regulates functions throughout human physiology, including neuropsychiatric, cardiovascular, autonomic, metabolic, and inflammatory states. The complex cellular interactions regulated by the ECS suggest a potential for vascular disease and stroke prevention by augmenting central nervous and immune cell endocannabinoid signaling.

Discussion: The endocannabinoid N-arachidonoylethanolamine (anandamide) plays a central role in augmenting these processes in cerebrovascular and neurometabolic disease. Furthermore, cannabidiol (CBD), a nonpsychoactive constituent of Cannabis, is an immediate therapeutic candidate both for potentiating endocannabinoid signaling and for acting at multiple pharmacological targets.

Conclusion: This speculative synthesis explores the current state of knowledge of the ECS and suggests CBD as a therapeutic candidate for stroke prevention by exerting favorable augmentation of the homeostatic effects of the ECS and, in turn, improving the metabolic syndrome, while simultaneously stalling the development of atherosclerosis.”

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Treatment of human spasticity with delta 9-tetrahydrocannabinol.

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“Spasticity is a common neurologic condition in patients with multiple sclerosis, stroke, cerebral palsy or an injured spinal cord. Animal studies suggest that THC has an inhibitory effect on polysynaptic reflexes.

Some spastic patients claim improvement after inhaling cannabis. We tested muscle tone, reflexes, strength and performed EMGs before and after double-blinded oral administration of either 10 or 5 mg THC or placebo.

10 mg THC significantly reduced spasticity by clinical measurement (P less than 0.01).

Responses varied, but benefit was seen in three of three patients with “tonic spasms.””

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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

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Smoking Marijuana Can Reduce Risk Of Stroke, Study Finds.

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“Smoking marijuana can reduce the risk of a stroke to a large extent, a new study has found. In the states where marijuana use is legal, strains of the drug are prescribed to cure chronic pain, anxiety, and epilepsy. A new study conducted by the University of Texas at Dallas has found cannabis can improve a person’s health by enhancing the blood and oxygen flow, thus reducing the risk of blood clots and the possibility of a stroke.” http://www.ibtimes.com/smoking-marijuana-can-reduce-risk-stroke-study-finds-2579489
“Residual Effects of THC via Novel Measures of Brain Perfusion and Metabolism in a Large Group of Chronic Cannabis Users” https://www.nature.com/npp/journal/vaop/ncurrent/full/npp201744a.html
“Could cannabis PROTECT you from a stroke? People who smoke marijuana every day have better blood flow and oxygen to the brain, controversial study claims. A study by the University of Texas at Dallas has found the drug can improve oxygen and blood flow to the brain, reducing the risk of clots that cause a brain attack. In fact, the research team found chronic cannabis users have the most efficient brain blood flow of all, suggesting their stroke risk is lowest.” http://www.dailymail.co.uk/health/article-4797444/Cannabis-PROTECTS-stroke-study-claims.html
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Modulation of Astrocyte Activity by Cannabidiol, a Nonpsychoactive Cannabinoid.

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“The astrocytes have gained in recent decades an enormous interest as a potential target for neurotherapies, due to their essential and pleiotropic roles in brain physiology and pathology. Their precise regulation is still far from understood, although several candidate molecules/systems arise as promising targets for astrocyte-mediated neuroregulation and/or neuroprotection.

The cannabinoid system and its ligands have been shown to interact and affect activities of astrocytes. Cannabidiol (CBD) is the main non-psychotomimetic cannabinoid derived from Cannabis. CBD is devoid of direct CB1 and CB2 receptor activity, but exerts a number of important effects in the brain. Here, we attempt to sum up the current findings on the effects of CBD on astrocyte activity, and in this way on central nervous system (CNS) functions, across various tested models and neuropathologies.

The collected data shows that increased astrocyte activity is suppressed in the presence of CBD in models of ischemia, Alzheimer-like and Multiple-Sclerosis-like neurodegenerations, sciatic nerve injury, epilepsy, and schizophrenia. Moreover, CBD has been shown to decrease proinflammatory functions and signaling in astrocytes.”

https://www.ncbi.nlm.nih.gov/pubmed/28788104

http://www.mdpi.com/1422-0067/18/8/1669

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Correlation Between Cannabidiol-Induced Reduction of Infarct Volume and Inflammatory Factors Expression in Ischemic Stroke Model.

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“Recent studies demonstrated that cannabidiol had neuroprotective property. There is some evidence about effective role of cannabidiol in reduction of ischemic damages. It has been reported that infarct size is influenced by various factors after MCAO, including inflammatory factors. The aim of the present study was to evaluate the effect of cannabidiol on infarction volume and correlation of infarct size with tumor necrosis factor receptor 1 (TNFR1), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) expression.

RESULTS:

The present results indicate that in the MCAO-induced cerebral ischemia, administration of cannabidiol (100 and 200 ng/rat) causes a significant reduction in infarction volume in comparison with the vehicle group. Also, there were significant correlations between decrease of regional infarct volume and TNFR1/NF-κB expression.

CONCLUSION:

The results of this study indicate that cannabidiol reduced cerebral infarction possibly through diminishing TNFR1/NF-κB-induced neurotoxicity in transient focal cerebral ischemia.”

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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.”

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Cannabinoid CB2 receptor ligand profiling reveals biased signalling and off-target activity

“The cannabinoid CB2 receptor (CB2R) represents a promising therapeutic target for various forms of tissue injury and inflammatory diseases. There is a great interest in the development of selective type-2 cannabinoid receptor (CB2R) agonists as potential drug candidates for various pathophysiological conditions, which include chronic and inflammatory pain, pruritus, diabetic neuropathy and nephropathy, liver cirrhosis, and protective effects after ischaemic-reperfusion injury.” https://www.nature.com/articles/ncomms13958

“Pain relief without the high. Researchers at Leiden University led by Mario van der Stelt (Leiden Institute for Chemistry) have set ‘gold standards’ for developing new painkillers based on the medicinal effects of cannabis.”  https://www.sciencedaily.com/releases/2017/01/170104103916.htm

ScienceDaily
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In vivo TSPO and cannabinoid receptor type 2 availability early in post-stroke neuroinflammation in rats: a positron emission tomography study.

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“Upregulated levels of 18-kDa translocator proteins (TSPO) and type 2 endocannabinoid receptors (CB2) are considered to reflect different aspects of microglia-related neuroinflammatory responses in the brain. Relative to the increase in the TSPO expression that occurs slightly later during neuroinflammation in a proinflammatory fashion, CB2 activation is considered to relate to the neuroprotective responses that occurs predominantly at an early stage of brain disorders. These findings, however, were deduced from studies with different animal samples under different experimental settings. Here, we aimed to examined the differences in TSPO binding and CB2 availability at an early stage of stroke in the same animal using positron emission tomography (PET).

CONCLUSIONS:

The present results provide in vivo evidence of different responses of microglia occurring in the acute state of stroke. The use of the CB2 tracer [11C]NE40 allows us to evaluate the roles played by the neuroprotective aspect of microglia in acute neuroinflammatory processes.” https://www.ncbi.nlm.nih.gov/pubmed/28356120

https://jneuroinflammation.biomedcentral.com/articles/10.1186/s12974-017-0851-4

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