Cannabinoid-induced apoptosis in immune cells as a pathway to immunosuppression.

Fig. 1

“Cannabinoids are a group of compounds found in the marijuana plant (Cannabis sativaL.). Marijuana has been used both for recreational and medicinal purposes for several centuries.

Cannabinoids have been shown to be effective in the treatment of nausea and vomiting associated with cancer chemotherapy, anorexia and cachexia seen in HIV/AIDS patients, as well as neuropathic pain, and spasticity in multiple sclerosis.

More recently, the anti-inflammatory properties of cannabinoids are drawing significant attention. In the last 15 years, studies with marijuana cannabinoids led to the discovery of cannabinoid receptors (CB1 and CB2) and their endogenous ligands, which make up what is known as the endocannabinoid system.

Cannabinoids are a group of compounds present in Cannabis plant (Cannabis sativa L.). They mediate their physiological and behavioral effects by activating specific cannabinoid receptors. With the recent discovery of the cannabinoid receptors (CB1 and CB2) and the endocannabinoid system, research in this field has expanded exponentially.

Cannabinoids have been shown to act as potent immunosuppressive and anti-inflammatory agents and have been shown to mediate beneficial effects in a wide range of immune-mediated diseases such as multiple sclerosis, diabetes, septic shock, rheumatoid arthritis, and allergic asthma.

Cannabinoid receptor 1 (CB1) is mainly expressed on the cells of the central nervous system as well as in the periphery. In contrast, cannabinoid receptor 2 (CB2) is predominantly expressed on immune cells. The precise mechanisms through which cannabinoids mediate immunosuppression is only now beginning to be understood…

In this review, we will focus on apoptotic mechanisms of immunosuppression mediated by cannabinoids on different immune cell populations and discuss how activation of CB2 provides a novel therapeutic modality against inflammatory and autoimmune diseases as well as malignancies of the immune system, without exerting the untoward psychotropic effects…

…cannabinoids do induce apoptosis in immune cells, alleviating inflammatory responses and protecting the host from acute and chronic inflammation.

The cumulative effect of cannabinoids on all cell populations of the immune system can be beneficial, when there is a need for immune suppression.

For example, in patients with autoimmune diseases such as multiple sclerosis, arthritis and lupus, or in those with septic shock, where the disease is caused by activated immune cells, targeting the immune cells via CB2 agonists may trigger apoptosis and act as anti-inflammatory therapy.

CB2 select agonists are not psychoactive and because CB2 is expressed primarily in immune cells, use of CB2 agonists could provide a novel therapeutic modality against autoimmune and inflammatory diseases.

In addition to the use of exogenous cannabinoids, in vivo manipulation of endocannabinoids may also offer novel treatment opportunities against cancer and autoimmune diseases.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3005548/

Direct suppression of autoreactive lymphocytes in the central nervous system via the CB2 receptor.

The cannabinoid system is evolutionally conserved and is present in invertebrates and vertebrates. One of the best-studied cannabinoids is Δ9-tetrahydrocannabinol (THC), the predominant active component of Cannabis sativa or marijuana.

The marijuana plant has been exploited by humans since their early history and was used for centuries in Asian medicine to reduce the severity of pain, inflammation and asthma. However, only recently have the mechanisms of the medicinal properties of THC begun to be understood. This understanding is largely due to the identification and cloning of two cannabinoid receptors.

The cannabinoid system is now recognized as a regulator of both the nervous and immune systems.

Although marijuana has been used for centuries for the treatment of a variety of disorders, its therapeutic mechanisms are only now being understood.

The best-studied plant cannabinoid, delta9-tetrahydrocannabinol (THC), produced by Cannabis sativa and found in marijuana, has shown evidence of being immunosuppressive in both in vivo and in vitro.

These studies are theoretically in agreement with the suggestions of others that cannabinoid receptor agonists would be beneficial for the treatment of MS in humans.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219523/

Multiple sclerosis may disrupt endocannabinoid brain protection mechanism

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“Since the discovery of the endocannabinoids [eCB; anandamide and 2-arachidonoylglycerol (2-AG), various pathological conditions were shown to increase the eCB tone and to inhibit molecular mechanisms that are involved in the production, release, and diffusion of harmful mediators such as proinflammatory cytokines or excess glutamate.

In this issue of PNAS, Witting et al.  demonstrate that, unexpectedly and contrary to the effects of other brain diseases, cell damage induced by experimental autoimmune encephalomyelitis (EAE), an immune-mediated disease widely used as a laboratory model of multiple sclerosis (MS), does not lead to enhancement of eCB levels, although the cannabinoid receptors remain functional.

Nearly two decades ago, Lyman et al.  reported that Δ9-THC, the psychoactive component of marijuana, suppresses the symptoms of EAE. A few years later, Wirguin et al. reported the same effect by Δ8-THC, a more stable and less psychotropic analogue of Δ9-THC.

Thus, THC was shown to inhibit both clinical and histological signs of EAE even before the endocannabinoids were described.

THC was also shown to control spasticity and tremor in chronic relapsing EAE, a further autoimmune model of MS , and to inhibit glutamate release via activation of the CB1-cannabinoid receptor in EAE. Moreover, mice deficient in the cannabinoid receptor CB1 tolerate inflammatory and excitotoxic insults poorly and develop substantial neurodegeneration after immune attack in EAE.

Thus, the brain loses some of its endogenous neuroprotective capacity, but it may still respond to exogenous treatment with 2-AG or other CB1 agonists. Assuming that the biochemical changes taking place in the EAE model of MS are similar to those in MS itself, these results represent a biochemical-based support to the positive outcome noted with cannabinoid therapy in MS.

These data suggest that the high level of IFN-γ in the CNS, noted in mice with EAE, disrupts eCB-mediated neuroprotection, while maintaining functional cannabinoid receptors, thus providing additional support for the use of cannabinoid-based medicine to treat MS.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1458835/

The role of the endocannabinoid system in atherosclerosis.

“Our current understanding of the pathophysiology of atherosclerosis suggests a prominent role for immune responses from its initiation through its complications. Given the increasing prevalence of cardiovascular risk factors worldwide, there is an urgent need to better understand the underlying mechanisms to improve current treatment protocols.

A growing body of evidence suggests that endocannabinoid signalling plays a critical role in the pathogenesis of atherogenesis and its clinical manifestations. Blocking CB(1) receptors has been shown to mediate not only weight reduction, but also several cardiometabolic effects in rodents and humans, indicating a potential relevance for the process of atherosclerosis.

Activation of CB(2) receptors with Delta(9)-tetrahydrocannabinol (THC) has been shown to inhibit atherosclerotic plaque progression in mice, mainly by inhibiting macrophage recruitment.

In conclusion, the precise role of the endocannabinoid system during atherosclerosis is not yet understood.”

http://www.ncbi.nlm.nih.gov/pubmed/18426500

http://www.thctotalhealthcare.com/category/atherosclerosis-2/

Cannabinoid receptors in atherosclerosis.

“…cannabinoid receptors are potential targets for the treatment of atherosclerosis…

Cannabinoids, such as Delta9-tetrahydrocannabinol, the major psychoactive compound of marijuana… was shown to inhibit disease progression through pleiotropic effects on inflammatory cells.

The development of novel cannabinoid receptor ligands that selectively target CB2 receptors or pharmacological modulation of the endocannabinoid system might offer novel therapeutic strategies in the treatment of atherosclerosis.

The immunomodulatory capacity of cannabinoids is now well established and suggests a broad therapeutic potential of cannabinoids for a variety of conditions, including atherosclerosis.”

http://www.ncbi.nlm.nih.gov/pubmed/16960500

http://www.thctotalhealthcare.com/category/atherosclerosis-2/

Cannabinoid receptors in acute and chronic complications of atherosclerosis

“Atherosclerosis is a chronic inflammatory disease that is the primary cause of myocardial infarction and stroke, which occur after sudden thrombotic occlusion of an artery.

A growing body of evidence suggests that cannabinoid signalling plays a fundamental role in atherosclerosis development and its clinical manifestations. Thus, CB2 receptors are protective in myocardial ischaemia/reperfusion and implicated in the modulation of chemotaxis, which is crucial for the recruitment of leukocytes during inflammation.

Delta-9-Tetrahydrocannabinol (THC)-mediated activation has been shown to inhibit atherosclerotic plaque progression in a CB2 dependent manner.

It is tempting to suggest that pharmacological modulation of the endocannabinoid system is a potential novel therapeutic strategy in the treatment of atherosclerosis.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219535/

Towards a therapeutic use of selective CB2 cannabinoid receptor ligands for atherosclerosis.

“Atherosclerosis remains the primary cause of heart disease and stroke, causing approximately 50% of all deaths in Western countries. The identification of promising novel anti-atherosclerotic therapies is therefore of great interest and represents a continued challenge to the medical community.

Cannabinoids, such as Delta9-tetrahydrocannabinol (THC), which is the major psychoactive compound of marijuana, modulate immune functions and might therefore be of therapeutic use for the treatment of inflammatory diseases.

The authors have demonstrated recently that oral treatment with low dose THC inhibits atherosclerosis progression in mice through pleiotropic immunomodulatory effects on inflammatory cells. All these effects were mediated via the cannabinoid receptor CB(2), the main cannabinoid receptor expressed on immune cells.

The identification and characterization of cannabinoid derivative that selectively activate CB(2) receptors and are devoid of adverse effects might offer a novel therapeutic strategy for the treatment of atherosclerosis.”

http://www.ncbi.nlm.nih.gov/pubmed/19804131

https://www.futuremedicine.com/doi/abs/10.2217/14796678.2.1.49

“Researchers suggest that THC and other cannabinoids, which are active at CB2, the cannabinoid receptor expressed on immune cells, may be valuable in treating atherosclerosis.” https://www.medscape.com/viewarticle/787468

Low dose oral cannabinoid therapy reduces progression of atherosclerosis in mice

Figure 1 : The cannabinoid receptor CB2 is expressed in human and mouse atherosclerotic plaques. Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, or to obtain a text description, please contact npg@nature.com

“Atherosclerosis is a chronic inflammatory disease… Derivatives of cannabinoids such as delta-9-tetrahydrocannabinol (THC) modulate immune functions and therefore have potential for the treatment of inflammatory diseases.

We investigated the effects of THC in a murine model of established atherosclerosis.

Oral administration of THC resulted in significant inhibition of disease progression.

Our data demonstrate that oral treatment with a low dose of THC inhibits atherosclerosis progression in the apolipoprotein E knockout mouse model, through pleiotropic immunomodulatory effects on lymphoid and myeloid cells.

Thus, THC or cannabinoids with activity at the CB2 receptor may be valuable targets for treating atherosclerosis.”

http://www.nature.com/nature/journal/v434/n7034/full/nature03389.html

http://www.ncbi.nlm.nih.gov/pubmed/15815632

 

Marijuana Chemical Fights Hardened Arteries – WebMD

WebMD: Better information. Better health.

“The active ingredient in marijuana that produces changes in brain messages appears to fight atherosclerosis — a hardening of the arteries.

It takes a very specific amount of THC — marijuana’s key chemical — to help the arteries. That dose is too low to produce mood-altering effects in the brain, according to the new study.

“It would be difficult to achieve such specific concentrations in the blood by smoking marijuana,” Roth explains in a Nature editorial.”

http://www.webmd.com/heart-disease/news/20050406/marijuana-chemical-fights-hardened-arteries

“Low dose oral cannabinoid therapy reduces progression of atherosclerosis in mice” http://www.nature.com/nature/journal/v434/n7034/full/nature03389.html

 http://www.thctotalhealthcare.com/category/atherosclerosis-2/

Cannabidiol: Pharmacology and potential therapeutic role in epilepsy and other neuropsychiatric disorders.

“Cannabis has been used to treat disease since ancient times. Δ9 -Tetrahydrocannabinol (Δ9 -THC) is the major psychoactive ingredient and CBD is the major nonpsychoactive ingredient in cannabis.

Cannabis and Δ9 -THC are anticonvulsant in most animal models but can be proconvulsant in some healthy animals. The psychotropic effects of Δ9 -THC limit tolerability.

CBD is anticonvulsant in many acute animal models, but there are limited data in chronic models.

The antiepileptic mechanisms of CBD are not known, but may include effects on the equilibrative nucleoside transporter; the orphan G-protein-coupled receptor GPR55; the transient receptor potential of vanilloid type-1 channel; the 5-HT1a receptor; and the α3 and α1 glycine receptors.

CBD has neuroprotective and antiinflammatory effects, and it appears to be well tolerated in humans, but small and methodologically limited studies of CBD in human epilepsy have been inconclusive.

More recent anecdotal reports of high-ratio CBD:Δ9 -THC medical marijuana have claimed efficacy, but studies were not controlled.

CBD bears investigation in epilepsy and other neuropsychiatric disorders, including anxiety, schizophrenia, addiction, and neonatal hypoxic-ischemic encephalopathy.”

http://www.ncbi.nlm.nih.gov/pubmed/24854329