Cannabinoid receptor 2 modulates susceptibility to experimental cerebral malaria through a CCL17-dependent mechanism.

“Cerebral malaria (CM) is a severe and often fatal complication of Plasmodium falciparum infection. It is characterized by parasite sequestration, a breakdown of the blood-brain-barrier and a strong inflammation in the brain.

We investigated the role of the cannabinoid receptor 2 (CB2), an important modulator of neuroinflammatory responses, in experimental cerebral malaria (ECM).

Strikingly, mice with a deletion of the CB2-encoding gene (Cnr2-/-) mice inoculated with Plasmodium berghei ANKA-erythrocytes exhibited enhanced survival and a diminished blood-brain-barrier disruption.

Therapeutic application of a specific CB2 antagonist also conferred increased ECM resistance in wild type mice.

Hematopoietic-derived immune cells were responsible for the enhanced protection in bone-marrow-chimeric (BM)-Cnr2-/- mice. Mixed BM-chimeras further revealed that CB2-expressing cells contributed to ECM development. A heterogeneous CD11b+ cell population, containing macrophages and neutrophils, expanded in the Cnr2-/- spleen after infection and expressed macrophage mannose receptors, arginase-1 activity and IL-10.

Also in the Cnr2-/-brain CD11b+ cells that expressed selected anti-inflammatory markers accumulated and expression of inflammatory mediators IFN-γ and TNF-α was reduced.

Finally, the M2-macrophage chemokine CCL17 was identified as essential factor for enhanced survival in the absence of CB2, since CCL17 x Cnr2 double-deficient mice were fully susceptible to ECM.

Thus, targeting CB2 may be promising for the development of alternative treatment regimes of ECM.”

http://www.ncbi.nlm.nih.gov/pubmed/27474745

The therapeutic potential of the phytocannabinoid cannabidiol for Alzheimer’s disease.

“Alzheimer’s disease (AD) is the most common neurodegenerative disorder, characterized by progressive loss of cognition. Over 35 million individuals currently have AD worldwide. Unfortunately, current therapies are limited to very modest symptomatic relief.

The brains of AD patients are characterized by the deposition of amyloid-β and hyperphosphorylated forms of tau protein. AD brains also show neurodegeneration and high levels of oxidative stress and inflammation.

The phytocannabinoid cannabidiol (CBD) possesses neuroprotective, antioxidant and anti-inflammatory properties and reduces amyloid-β production and tau hyperphosphorylation in vitro.

CBD has also been shown to be effective in vivo making the phytocannabinoid an interesting candidate for novel therapeutic interventions in AD, especially as it lacks psychoactive or cognition-impairing properties.

CBD treatment would be in line with preventative, multimodal drug strategies targeting a combination of pathological symptoms, which might be ideal for AD therapy.

Thus, this review will present a brief introduction to AD biology and current treatment options before outlining comprehensively CBD biology and pharmacology, followed by in-vitro and in-vivo evidence for the therapeutic potential of CBD. We will also discuss the role of the endocannabinioid system in AD before commenting on the potential future of CBD for AD therapy (including safety aspects).”

http://www.ncbi.nlm.nih.gov/pubmed/27471947

Delayed treatment with cannabidiol has a cerebroprotective action via a cannabinoid receptor-independent myeloperoxidase-inhibiting mechanism.

“We examined the neuroprotective mechanism of cannabidiol, non-psychoactive component of marijuana, on the infarction in a 4 h mouse middle cerebral artery (MCA) occlusion model in comparison with Delta(9)-tetrahydrocannabinol (Delta(9)-THC).

Both pre- and post-ischemic treatment with cannabidiol resulted in potent and long-lasting neuroprotection, whereas only pre-ischemic treatment with Delta(9)-THC reduced the infarction.

Unlike Delta(9)-THC, cannabidiol did not affect the excess release of glutamate in the cortex after occlusion.

Cannabidiol suppressed the decrease in cerebral blood flow by the failure of cerebral microcirculation after reperfusion and inhibited MPO activity in neutrophils.

Furthermore, the number of MPO-immunopositive cells was reduced in the ipsilateral hemisphere in cannabidiol-treated group.

Cannabidiol provides potent and long-lasting neuroprotection through an anti-inflammatory CB(1) receptor-independent mechanism, suggesting that cannabidiol will have a palliative action and open new therapeutic possibilities for treating cerebrovascular disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/17437545

Cannabidiol prevents a post-ischemic injury progressively induced by cerebral ischemia via a high-mobility group box1-inhibiting mechanism.

“We examined the cerebroprotective mechanism of cannabidiol, the non-psychoactive component of marijuana, against infarction in a 4-h mouse middle cerebral artery (MCA) occlusion model.

Cannabidiol was intraperitoneally administrated immediately before and 3h after cerebral ischemia.

Cannabidiol significantly prevented infarction and MPO activity at 20h after reperfusion.

Cannabidiol inhibited the MPO-positive cells expressing HMGB1 and also decreased the expression level of HMGB1 in plasma.

In addition, cannabidiol decreased the number of Iba1- and GFAP-positive cells at 3 days after cerebral ischemia.

Moreover, cannabidiol improved neurological score and motor coordination on the rota-rod test.

Our results suggest that cannabidiol inhibits monocyte/macropharge expressing HMGB1 followed by preventing glial activation and neurological impairment induced by cerebral ischemia.

Cannabidiol will open new therapeutic possibilities for post-ischemic injury via HMGB1-inhibiting mechanism.”

http://www.ncbi.nlm.nih.gov/pubmed/18634812

The future of cannabinoids as analgesic agents: a pharmacologic, pharmacokinetic, and pharmacodynamic overview.

 

“For thousands of years, physicians and their patients employed cannabis as a therapeutic agent.

Despite this extensive historical usage, in the Western world, cannabis fell into disfavor among medical professionals because the technology available in the 1800s and early 1900s did not permit reliable, standardized preparations to be developed.

However, since the discovery and cloning of cannabinoid receptors (CB1 and CB2) in the 1990s, scientific interest in the area has burgeoned, and the complexities of this fascinating receptor system, and its endogenous ligands, have been actively explored.

Recent studies reveal that cannabinoids have a rich pharmacology and may interact with a number of other receptor systems-as well as with other cannabinoids-to produce potential synergies.

Cannabinoids-endocannabinoids, phytocannabinoids, and synthetic cannabinoids-affect numerous bodily functions and have indicated efficacy of varying degrees in a number of serious medical conditions.

Cannabinoid receptor agonists and/or molecules that affect the modulation of endocannabinoid synthesis, metabolism, and transport may, in the future, offer extremely valuable tools for the treatment of a number of currently intractable disorders.”

 http://www.ncbi.nlm.nih.gov/pubmed/17890938

Cannabinoids in bipolar affective disorder: a review and discussion of their therapeutic potential.

“Bipolar affective disorder is often poorly controlled by prescribed drugs.

Cannabis use is common in patients with this disorder and anecdotal reports suggest that some patients take it to alleviate symptoms of both mania and depression.

We undertook a literature review of cannabis use by patients with bipolar disorder and of the neuropharmacological properties of cannabinoids suggesting possible therapeutic effects in this condition.

No systematic studies of cannabinoids in bipolar disorder were found to exist, although some patients claim that cannabis relieves symptoms of mania and/or depression.

The cannabinoids Delta(9)-tetrahydrocannabinol (THC) and cannabidiol (CBD) may exert sedative, hypnotic, anxiolytic, antidepressant, antipsychotic and anticonvulsant effects.

Pure synthetic cannabinoids, such as dronabinol and nabilone and specific plant extracts containing THC, CBD, or a mixture of the two in known concentrations, are available and can be delivered sublingually.

Controlled trials of these cannabinoids as adjunctive medication in bipolar disorder are now indicated.”

http://www.ncbi.nlm.nih.gov/pubmed/15888515

The cannabinoids: therapeutic potentials.

 

“A review of the therapeutic potentials of the cannabinoids is presented. With respect to the antifertility aspects of cannabinoids, 2 mg delta 9-THC suppressed luteinizing hormone secretion in rats and 2 and 3 mg/kg resulted in a deterioation of male sexual performance. A new chapter in marijuana research was opened in 1964 with the identification of delta 9-tetrahydrocannabinol as the active ingredient. Antiedema, analgesic, antipyretic, antiinflammatory, antifertility, antiepileptic, anticonvulsant, antihypertensive, cardiotonic, pulmonary, and antidepressant effects along with potentiation of barbiturates and analgesics are reviewed leading one to the conclusion that marijuana is “a drug for all reasons”. During the past decade many investigators have pursued the possibility of modification of the delta 9 structure to delineate activities. 1 compound, Abbott 40656, SP106, a water-soluble benzopyran derivative is presently under Phase 1 clinical evaluation as a sedative-hypnotic.”

http://www.ncbi.nlm.nih.gov/pubmed/12307093/

Blood pressure regulation by endocannabinoids and their receptors

Logo of nihpa

“Cannabinoids and their endogenous and synthetic analogs exert powerful hypotensive and cardiodepressor effects by complex mechanisms involving direct and indirect effects on myocardium and vasculature.

On the one hand, endocannabinoids and cannabinoid receptors have been implicated in the hypotensive state associated with hemorrhagic, endotoxic and cardiogenic shock, and advanced liver cirrhosis.

On the other hand, there is emerging evidence suggesting that the endocannabinergic system plays an important role in the cardiovascular regulation in hypertension.

This review is aimed to discuss the in vivo hypotensive and cardiodepressant effects of cannabinoids mediated by cannabinoid and TRPV1 receptors, and focuses on the novel therapeutical strategies offered by targeting the endocannabinoid system in the treatment of hypertension.

The endocannabinergic system plays an important cardiovascular regulatory role not only in pathophysiological conditions associated with excessive hypotension but also in hypertension.

Thus, the pharmacological manipulation of this system may offer novel therapeutic approaches in a variety of cardiovascular disorders.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2225528/

The synthetic cannabinoids attenuate allodynia and hyperalgesia in a rat model of trigeminal neuropathic pain.

 

“Trigeminal neuralgia is a disorder of paroxysmal and severely disabling facial pain and continues to be a real therapeutic challenge.

At present there are few effective drugs. Here we have evaluated the effects of the synthetic cannabinoid WIN 55,212-2 on mechanical allodynia and thermal hyperalgesia in a rat model of trigeminal neuropathic pain produced by a chronic constriction injury (CCI) of the infraorbital branch of the trigeminalnerve (ION).

Taken together, these results suggest that cannabinoids may be a useful therapeutic approach for the clinical management of trigeminal neuropathic pain disorders.”

The CB1 Antagonist, SR141716A, Is Protective in Permanent Photothrombotic Cerebral Ischemia.

“Modulation of the endocannabinoid system has been shown to have a significant impact on outcomes in animal models of stroke.

We have previously reported a protective effect of the CB1 antagonist, SR141716A, in a transient reperfusion mouse model of cerebral ischemia. This protective effect was in part mediated by activation of the 5HT1A receptor.

Here we have examined its effect in a mouse model of permanent ischemia induced by photoinjury.

The CB1 antagonist was found to be protective in this model.

As was the case following transient ischemia reperfusion, SR141716A (5mg/kg) resulted in smaller infarct fractions and stroke volumes when utilized both as a pretreatment and as a post-treatment. In contrast to the effect in a transient ischemia model, the pretreatment effect did not depend on the 5HT1A receptor.

Neurological function correlated favorably to the reduction in stroke size when SR141716A was given as a pretreatment.

With the incidence of stroke predicted to rise in parallel with an ever aging population, understanding mechanisms underlying ischemia and therapeutics remains a paramount goal of research.”

http://www.ncbi.nlm.nih.gov/pubmed/27453059