Symptomatic therapy in multiple sclerosis: the role of cannabinoids in treating spasticity

“Anecdotal evidence suggests a beneficial effect of cannabis on spasticity as well as pain. Recently, randomized, double-blind, placebo-controlled studies have confirmed the clinical efficacy of cannabinoids for the treatment of spasticity in patients with MS. Based on these data, nabiximols (Sativex), a 1:1 mix of Δ-9-tetrahydrocannabinol and cannabidiol extracted from cloned Cannabis sativa chemovars, received approval for treating MS-related spasticity in various countries around the globe. In this article we review the current understanding of cannabinoid biology and the value of cannabinoids as a symptomatic treatment option addressing spasticity in patients with MS.

Based on individual case reports, the consumption of plant parts, specifically, the resin of the Cannabis sativa hemp plant, has, for years, been attributed to the capacity to reduce the symptoms of multiple sclerosis (MS), such as spasticity, neuropathic pain, tremor, and disturbed bladder function. As characterization of the endocannabinoid system and its role in the motor system and pain processing continue to advance, there is increasing evidence of a scientific basis for the postulated therapeutic effect of cannabis derivatives.

The oromucosal administration of THC and CBD in a 1:1 ratio has proven to be a well tolerated therapeutic option for treating spasticity in patients with MS who respond poorly to conventional antispastic drugs. Assessment of the efficacy is limited by the fact that spasticity as a symptom is very difficult to measure reliably, objectively, and validly. Current study data support the position that the beneficial effects of nabiximols on subjective and objective endpoints in a selected patient sample outweigh the adverse pharmaceutical effects. The effects of long-term nabiximols treatment on neuropsychological processes and the structure of the endocannabinoid system need to be further characterized.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3437528/

Beneficial effect of the non-psychotropic plant cannabinoid cannabigerol on experimental inflammatory bowel disease.

“Inflammatory bowel disease (IBD) is an incurable disease which affects millions of people in industrialised countries. Anecdotal and scientific evidence suggest that Cannabis use may have a positive impact in IBD patients.

 Here, we investigated the effect of cannabigerol (CBG), a non-psychotropic Cannabis-derived cannabinoid, in a murine model of colitis…

  In conclusion, CBG attenuated murine colitis, reduced nitric oxide production in macrophages (effect being modulated by the CB(2) receptor) and reduced ROS formation in intestinal epithelial cells.

CBG could be considered for clinical experimentation in IBD patients.”

http://www.ncbi.nlm.nih.gov/pubmed/23415610

Cannabis may help reverse dementia: study

“It makes most people a little foggy-headed, but scientists are investigating whether an active ingredient in cannabis could actually stave off dementia.

A team from Neuroscience Research Australia is in the early stages of research examining if one of the main active ingredients in cannabis, called cannabidiol, could reverse some of the symptoms of memory loss in animals.

Tim Karl, a senior research fellow with the group, said cannabidiol does not have the same psychoactive effects as the main component of marijuana, THC, but it has been found to have anti-inflammatory, antioxidant and other effects that could be beneficial for the brain.”

Read more: http://www.narrominenewsonline.com.au/story/1283217/cannabis-may-help-reverse-dementia-study/

Role of cannabinoids and endocannabinoids in cerebral ischemia

“The human costs of stroke are very large and growing; it is the third largest cause of death in the United States and survivors are often faced with loss of ability to function independently. There is a large need for therapeutic approaches that act to protect neurons from the injury produced by ischemia and reperfusion… 

 Overall, the available data suggest that inhibition of CB1 receptor activation together with increased CB2 receptor activation produces beneficial effects.

These studies support the hypothesis that activation of the CB1 receptor by highly efficacious, exogenous agonists during the acute phase of ischemia decreases the likelihood of the occurrence of a detrimental event at the time of ischemia and thereby reduces the amount of infarction and neuronal death long-term… A protective role of the CB1 receptor is also supported by studies…

While it is possible that the ECS will be added to the long list of neuroprotective agents that show promise in animals and do not work in humans, there are a few reasons to be optimistic about this class of drugs. First, many of the other agents did not work because they do not cross the blood brain barrier. While the considerable lipophilicity of the cannabinoids poses its own set of problems, these drugs have no problems entering the brain. Second, the ECS is multifactorial and could “cover” multiple biochemical pathways in a single drug. Third, manipulations of the ECS has been shown to be beneficial in several preclinical models. Only time and further research will answer the most important question, are the cannabinoids of therapeutic benefit in humans suffering from stroke?”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2581413/

 

Endocannabinoids and cannabinoid receptors in ischaemia–reperfusion injury and preconditioning

“This review is aimed to discuss the role of endocannabinoids and CB receptors in various forms of I/R injury (myocardial, cerebral, hepatic and circulatory shock) and preconditioning, and to delineate the evidence supporting the therapeutic utility of selective CB2 receptor agonists, which are devoid of psychoactive effects, as a promising new approach to limit I/R-induced tissue damage.

In this review, we will discuss the triggers and sources of endocannabinoid production during various forms of I/R injury (myocardial, cerebral, hepatic and retinal ischaemia, and circulatory shock) and preconditioning, as well as the diverse role of these novel mediators and their receptors in these processes. We will also overview the accumulating evidence obtained through the use of various synthetic CB1/CB2 receptor ligands, with particular focus on the novel role of CB2 receptors, suggesting that the modulation of the endocannabinoid system can be therapeutically exploited in various forms of I/R injury.

Cerebral I/R (stroke)

The first evidence for the neuroprotective effect of CBs came from the stroke research field from studies using synthetic non-psychotropic CB Dexanabinol/HU-211, which exerted its beneficial effects through CB1/CB2-independent mechanisms.

Collectively, it appears that both CB1 agonists and antagonists may afford neuroprotective effects against cerebral I/R…

There is considerable interest in the development of selective CB2 receptor agonists, which are devoid of psychoactive properties of CB1 agonists, for various inflammatory disorders. Further studies should also establish the therapeutic window of protection during the reperfusion phase with the currently available CB2 receptor agonists, and new compounds should also be designed with better in vivo bioavailability, to devise clinically relevant treatment strategies against various forms of I/R. Nevertheless, the recently observed beneficial effects of CB2 receptor agonists in hepatic and other forms of I/R, coupled with the absence of psychoactive properties, and antifibrotic effects of CB2 receptor in the liver suggest that this approach may represent a novel promising strategy against various forms of I/R injury and other inflammatory disorders.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219536/

The endocannabinoid system and Alzheimer’s disease.

“The importance of the role of the endocannabinoid system (ECS) in neurodegenerative diseases has grown during the past few years. Mostly because of the high density and wide distribution of cannabinoid receptors of the CB(1) type in the central nervous system (CNS), much research focused on the function(s) that these receptors might play in pathophysiological conditions.

Our current understanding, however, points to much diverse roles for this system. In particular, other elements of the ECS, such as the fatty acid amide hydrolase (FAAH) or the CB(2) cannabinoid receptor are now considered as promising pharmacological targets for some diseases and new cannabinoids have been incorporated as therapeutic tools.

 Although still preliminary, recent reports suggest that the modulation of the ECS may constitute a novel approach for the treatment of Alzheimer’s disease (AD). Data obtained in vitro, as well as in animal models for this disease and in human samples seem to corroborate the notion that the activation of the ECS, through the use of agonists or by enhancing the endogenous cannabinoid tone, may induce beneficial effects on the evolution of this disease.”

http://www.ncbi.nlm.nih.gov/pubmed/17952652

Differential transcriptional profiles mediated by exposure to the cannabinoids cannabidiol and Δ9-tetrahydrocannabinol in BV-2 microglial cells.

“Apart from their effects on mood and reward, cannabinoids exert beneficial actions such as neuroprotection and attenuation of inflammation. The immunosuppressive activity of cannabinoids has been well established. We previously showed that the psychoactive cannabinoid Δ(9) -tetrahydrocannabinol (THC) and the non-psychoactive cannabidiol (CBD) differ in their anti-inflammatory signalling pathways.

CONCLUSIONS AND IMPLICATIONS:

These observations indicated that CBD, but much less than THC, induced a cellular stress response in microglial cells and suggested that this effect could underlie its anti-inflammatory activity.”

http://www.ncbi.nlm.nih.gov/pubmed/21542829

Smoked Medical Cannabis May Be Beneficial as Treatment for Chronic Neuropathic Pain, Study Suggests.

“Medicinal marijuana. A new study provides evidence that cannabis may offer relief to patients suffering from chronic neuropathic pain. (Credit: iStockphoto)”
 

“The medicinal use of cannabis has been debated by clinicians, researchers, legislators and the public at large for many years as an alternative to standard pharmaceutical treatments for pain, which may not always be effective and may have unwanted side effects. A new study by McGill University Health Centre (MUHC) and McGill University researchers provides evidence that cannabis may offer relief to patients suffering from chronic neuropathic pain.”

“This is the first trial to be conducted where patients have been allowed to smoke cannabis at home and to monitor their responses, daily,” says Dr. Mark Ware, lead author of the study, who is also Director of Clinical Research at the Alan Edwards Pain Management Unit at the MUHC and an assistant professor of anesthesia in McGill University’s Faculty of Medicine, and neuroscience researcher at the Research Institute of the MUHC.

In this study, low doses (25mg) of inhaled cannabis containing approximately 10% THC (the active ingredient in cannabis), smoked as a single inhalation using a pipe three times daily over a period of five days, offered modest pain reduction in patients suffering from chronic neuropathic pain (pain associated with nerve injury) within the first few days. The results also suggest that cannabis improved moods and helped patients sleep better. The effects were less pronounced in cannabis strains containing less than 10% THC.

“The patients we followed suffered from pain caused by injuries to the nervous system from post-traumatic (e.g. traffic accidents) or post-surgical (e.g. cut nerves) events, and which was not controlled using standard therapies” explains Dr. Ware. “This kind of pain occurs more frequently than many people recognize, and there are few effective treatments available. For these patients, medical cannabis is sometimes seen as their last hope.”

“This study marks an important step forward because it demonstrates the analgesic effects of cannabis at a low dose over a shot period of time for patients suffering from chronic neuropathic pain,” adds Dr. Ware. The study used herbal cannabis from Prairie Plant Systems (under contract to Health Canada to provide cannabis for research and medical purposes), and a 0% THC ‘placebo’ cannabis from the USA.”

Read more:http://www.sciencedaily.com/releases/2010/08/100830094926.htm

Discovery and development of endocannabinoid-hydrolyzing enzyme inhibitors.

Abstract

“Fatty acid amide hydrolase (FAAH) and monoglyceride lipase (MGL) are hydrolytic enzymes which degrade the endogenous cannabinoids (endocannabinoids) N-arachidonoylethanolamine (anandamide, AEA) and 2-arachidonoylglycerol (2-AG), respectively. Endocannabinoids are an important class of lipid messenger molecules that are produced on demand in response to elevated intracellular calcium levels. They recognize and activate the cannabinoid CB(1) and CB(2) receptors, the molecular targets for Delta(9)-tetrahydrocannabinol (Delta(9)-THC) in marijuana evoking several beneficial therapeutic effects. However, in vivo the cannabimimetic effects of AEA and 2-AG remain weak owing to their rapid inactivation by FAAH and MGL, respectively. The inactivation of FAAH and MGL by specific enzyme inhibitors increases the levels of AEA and 2-AG, respectively, producing therapeutic effects such as pain relief and depression of anxiety.”

http://www.ncbi.nlm.nih.gov/pubmed/20370710

Nonpsychotropic Cannabinoid Receptors Regulate Microglial Cell Migration

“During neuroinflammation, activated microglial cells migrate toward dying neurons, where they exacerbate local cell damage. The signaling molecules that trigger microglial cell migration are poorly understood. In this paper, we show that pathological overstimulation of neurons by glutamate plus carbachol dramatically increases the production of the endocannabinoid 2-arachidonylglycerol (2-AG) but only slightly increases the production of anandamide and does not affect the production of two putative endocannabinoids, homo-γ-linolenylethanolamide and docosatetraenylethanolamide. We further show that pathological stimulation of microglial cells with ATP also increases the production of 2-AG without affecting the amount of other endocannabinoids. Using a Boyden chamber assay, we provide evidence that 2-AG triggers microglial cell migration. This effect of 2-AG occurs through CB2 and abnormal-cannabidiol-sensitive receptors, with subsequent activation of the extracellular signal-regulated kinase 1/2 signal transduction pathway. It is important to note that cannabinol and cannabidiol, two nonpsychotropic ingredients present in the marijuana plant, prevent the 2-AG-induced cell migration by antagonizing the CB2 and abnormal-cannabidiol-sensitive receptors, respectively. Finally, we show that microglial cells express CB2 receptors at the leading edge of lamellipodia, which is consistent with the involvement of microglial cells in cell migration. Our study identifies a cannabinoid signaling system regulating microglial cell migration. Because this signaling system is likely to be involved in recruiting microglial cells toward dying neurons, we propose that cannabinol and cannabidiol are promising nonpsychotropic therapeutics to prevent the recruitment of these cells at neuroinflammatory lesion sites.”

“Because marijuana produces remarkable beneficial effects, patients with multiple sclerosis, for example, commonly use this plant as a therapeutic agent; however, we still lack essential information on the mechanistic basis of these beneficial effects.”

“The marijuana plant, Cannabis sativa, contains >60 cannabinoid compounds, the best known being Δ9-tetrahydrocannabinol (THC), cannabinol (CBN), and cannabidiol (CBD) (for review, see. Cannabinoid compounds produce their biological effects by acting through at least three cannabinoid receptors (see Table1). These include the cloned cannabinoid CB1 receptors, which are expressed predominately in the CNS, the cloned cannabinoid CB2 receptors, which are expressed predominately by immune cells, and the abnormal-cannabidiol-sensitive receptors (hereafter referred to as abn-CBD receptors). The latter receptors have not been cloned yet, but they have been pinpointed pharmacologically in mice lacking CB1 and CB2 receptors and are also known as anandamide (AEA) receptors.”

“We also show that CBN and CBD, two nonpsychotropic bioactive compounds of marijuana, may antagonize the 2-AG-induced recruitment of microglial cells. This is in agreement with the fact that nabilone, a synthetic analog of THC, produces minimal palliative effects against multiple sclerosis symptoms, whereas smoking cannabis is reported to be beneficial. Therefore, our results suggest that bioactive cannabinoids present in the marijuana plant, such as CBN and CBD, are likely to underlie the increased efficacy of cannabis versus nabilone and therefore hold promise as nonpsychotropic therapeutics to treat neuroinflammation.”

http://www.jneurosci.org/content/23/4/1398.long