Discovery of Selective Cannabinoid CB2 Receptor Agonists by High-Throughput Screening.

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“The endocannabinoid system (ECS) plays a diverse role in human physiology ranging from the regulation of mood and appetite to immune modulation and the response to pain.

Drug development that targets the cannabinoid receptors (CB1 and CB2) has been explored; however, success in the clinic has been limited by the psychoactive side effects associated with modulation of the neuronally expressed CB1 that are enriched in the CNS. CB2, however, are expressed in peripheral tissues, primarily in immune cells, and thus development of CB2-selective drugs holds the potential to modulate pain among other indications without eliciting anxiety and other undesirable side effects associated with CB1 activation.

As part of a collaborative effort among industry and academic laboratories, we performed a high-throughput screen designed to discover selective agonists or positive allosteric modulators (PAMs) of CB2. Although no CB2 PAMs were identified, 167 CB2 agonists were discovered here, and further characterization of four select compounds revealed two with high selectivity for CB2 versus CB1.

These results broaden drug discovery efforts aimed at the ECS and may lead to the development of novel therapies for immune modulation and pain management with improved side effect profiles.”

https://www.ncbi.nlm.nih.gov/pubmed/29257918

 

Cannabinoids for the treatment of neuropsychiatric symptoms, pain and weight loss in dementia.

“Efficacious treatment for neuropsychiatric symptoms (NPS), pain and weight loss for dementia patients is desperately needed.

This review presents an up-to-date look at the literature investigating the use of cannabinoid for these symptoms in dementia.

RECENT FINDINGS:

We searched electronically for publications regarding cannabinoid use in dementia, with a focus on Alzheimer’s disease. Seven studies and one case report have been conducted to examine the use of cannabinoids for the treatment of NPS of dementia, and three of these trials reported on the effect of cannabinoids on weight. Five studies reported decreased agitation or improvements in sleep with cannabinoid use. One crossover trial found that cannabinoids positively impacted weight, whereas a chart review study found no impact on weight with cannabinoids, but an increase in food intake. There were no trials examining the use of cannabinoids for pain in dementia.

SUMMARY:

Findings from trials with small sample sizes and various clinical populations suggest that cannabinoid use may be well tolerated and effective for treatment of NPS such as agitation as well as weight and pain management in patients with dementia. Additional studies are necessary to further elucidate the relative risks and benefits of this treatment.”

Therapeutic Value of Medical Marijuana in New Jersey Patients: A Community Partnership Research Endeavor.

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“The Public Health Program at Stockton University partnered with the Compassionate Care Foundation to ascertain the impact of medical marijuana on patients in New Jersey.

Results provide insight into the diagnoses for which patients used medical marijuana.

Results indicate increased mood, general overall condition, and energy as the highest consequences; level of pain in the middle range; and most frequent usage as 3 to 4 times a day. Repeated measures done after visit 2 showed eight statistically significant differences for patients after using medical marijuana: an increase in general quality of life, mobility, and mood, with a decrease in inflammation, intraocular pressure, spasms, seizures, and pain.

Results after visit 3 indicated seven significant differences compared to visit 1: decreased seizures, intraocular pressure, spasms, nausea, and pain, along with increased energy and mobility. No differences were found by patient diagnosis or age, but sex-related differences occurred in inflammation, mood, and energy.

Results support positive therapeutic benefits of medical marijuana, and despite methodological limitations, our study contributes to the growing body of literature.”

https://www.ncbi.nlm.nih.gov/pubmed/29202158

 

Antinociceptive effects of mixtures of mu opioid receptor agonists and cannabinoid receptor agonists in rats: impact of drug and fixed-dose ratio.

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“Pain is a significant clinical problem, and there is a need for effective pharmacotherapies with fewer adverse effects than currently available drugs (e.g., mu opioid receptor agonists).

Cannabinoid receptor agonists enhance the antinociceptive effects of mu opioid receptor agonists, but it remains unclear which drugs and in what proportion will yield the most effective and safest treatments.

The antinociceptive effects of the mu opioid receptor agonists etorphine and morphine alone and in combination with the cannabinoid receptor agonists Δ9-THC and CP55940 were studied in male Sprague-Dawley rats (n=16) using a warm water tail withdrawal procedure.

The ratio of opioid to cannabinoid (3:1, 1:1, and 1:3) varied for each mixture. Drugs administered alone or as pairwise mixtures of an opioid and a cannabinoid dose-dependently increased tail withdrawal latency. Mixtures with morphine produced supra-additive (CP55940) and additive (Δ9-THC) effects, whereas mixtures with etorphine and either cannabinoid were sub-additive. The interactions were not different among ratios for a particular mixture.

The nature of the interaction between opioids and cannabinoids with regard to antinociceptive effects varies with the particular drugs in the mixture, which can have implications for designing combination therapies for pain.”

https://www.ncbi.nlm.nih.gov/pubmed/29183835

http://www.sciencedirect.com/science/article/pii/S0014299917307719

Acetaminophen Relieves Inflammatory Pain Through CB1 Cannabinoid Receptors in the Rostral Ventromedial Medulla.

Journal of Neuroscience

“Acetaminophen (paracetamol) is a widely used analgesic and antipyretic drug with only incompletely understood mechanisms of action.

Previous work, using models of acute nociceptive pain, indicated that analgesia by acetaminophen involves an indirect activation of CB1 receptors by the acetaminophen metabolite and endocannabinoid re-uptake inhibitor AM 404.  However, the contribution of the cannabinoid system to anti-hyperalgesia against inflammatory pain, the main indication of acetaminophen, and the precise site of the relevant CB1 receptors have remained elusive.

Here, we analyzed acetaminophen analgesia in mice of either sex with inflammatory pain and found that acetaminophen exerted a dose-dependent anti-hyperalgesic action, which was mimicked by intrathecally injected AM 404. Both compounds lost their anti-hyperalgesic activity in CB1-/- mice confirming the involvement of the cannabinoid system.

Our results indicate that the cannabinoid system contributes not only to acetaminophen analgesia against acute pain but also against inflammatory pain, and suggest that the relevant CB1 receptors reside in the RVM.

SIGNIFICANCE STATEMENT: Acetaminophen is a widely used analgesic drug with multiple but only incompletely understood mechanisms of action including a facilitation of endogenous cannabinoid signaling via one of its metabolites. Our present data indicate that enhanced cannabinoid signaling is also responsible for the analgesic effects of acetaminophen against inflammatory pain. Local injections of the acetaminophen metabolite AM 404 and of cannabinoid receptor antagonists as well as data from tissue specific CB1 receptor deficient mice suggest the rostral ventromedial medulla as an important site of the cannabinoid-mediated analgesia by acetaminophen.”

https://www.ncbi.nlm.nih.gov/pubmed/29167401

http://www.jneurosci.org/content/early/2017/11/22/JNEUROSCI.1945-17.2017

Current evidence of cannabinoid-based analgesia obtained in preclinical and human experimental settings.

European Journal of Pain

“Cannabinoids have a long record of recreational and medical use and become increasingly approved for pain therapy. This development is based on preclinical and human experimental research summarized in this review.

Cannabinoid CB1 receptors are widely expressed throughout the nociceptive system. Their activation by endogenous or exogenous cannabinoids modulates the release of neurotransmitters. This is reflected in antinociceptive effects of cannabinoids in preclinical models of inflammatory, cancer and neuropathic pain, and by nociceptive hypersensitivity of cannabinoid receptor-deficient mice.

Cannabis-based medications available for humans mainly comprise Δ9 -tetrahydrocannabinol (THC), cannabidiol (CBD) and nabilone.

During the last 10 years, six controlled studies assessing analgesic effects of cannabinoid-based drugs in human experimental settings were reported. An effect on nociceptive processing could be translated to the human setting in functional magnetic resonance imaging studies that pointed at a reduced connectivity within the pain matrix of the brain. However, cannabinoid-based drugs heterogeneously influenced the perception of experimentally induced pain including a reduction in only the affective but not the sensory perception of pain, only moderate analgesic effects, or occasional hyperalgesic effects. This extends to the clinical setting.

While controlled studies showed a lack of robust analgesic effects, cannabis was nearly always associated with analgesia in open-label or retrospective reports, possibly indicating an effect on well-being or mood, rather than on sensory pain. Thus, while preclinical evidence supports cannabinoid-based analgesics, human evidence presently provides only reluctant support for a broad clinical use of cannabinoid-based medications in pain therapy.

SIGNIFICANCE:

Cannabinoids consistently produced antinociceptive effects in preclinical models, whereas they heterogeneously influenced the perception of experimentally induced pain in humans and did not provide robust clinical analgesia, which jeopardizes the translation of preclinical research on cannabinoid-mediated antinociception into the human setting.”

https://www.ncbi.nlm.nih.gov/pubmed/29160600

http://onlinelibrary.wiley.com/doi/10.1002/ejp.1148/abstract?systemMessage=Wiley+Online+Library+usage+report+download+page+will+be+unavailable+on+Friday+24th+November+2017+at+21%3A00+EST+%2F+02.00+GMT+%2F+10%3A00+SGT+%28Saturday+25th+Nov+for+SGT+

Modulating the endocannabinoid pathway as treatment for peripheral neuropathic pain: a selected review of preclinical studies.

“Chemotherapy-induced neuropathic pain is a distressing and commonly occurring side effect of many commonly used chemotherapeutic agents, which in some cases may prevent cancer patients from being able to complete their treatment.

Cannabinoid based therapies have the potential to manage or even prevent pain associated with this syndrome.

Pre-clinical animal studies that investigate the modulation of the endocannabinoid system (endogenous cannabinoid pathway) are being conducted to better understand the mechanisms behind this phenomenon.

Five recent pre-clinical studies identified from Medline published between 2013 and 2016 were selected for review. All studies evaluated the effect of small-molecule agonists or antagonists on components of the endocannabinoid system in rats or mice, using cisplatin or paclitax-el-induced allodynia as a model of chemotherapy-induced neuropathic pain. Activation of the cannabinoid receptor-2 (CB-2) receptor by AM1710 blocked paclitaxel-induced mechanical and cold allodynia in one study.

Four studies investigating the activation of both cannabinoid receptor-1 (CB-1) and CB-2 receptors by dual-agonists (WIN55,21 and CP55,940), or by the introduction of inhibitors of endocannabinoid metabolisers (URB597, URB937, JZL184, and SA-57) showed reduction of chemotherapy-induced al-lodynia. In addition, their results suggest that anti-allodynic effects may also be mediated by additional receptors, including TRPV1 and 5-hydroxytryptamine (5-HT1A).

Pre-clinical studies demon-strate that the activation of endocannabinoid CB-1 or CB-2 receptors produces physiological effects in animal models, namely the reduction of chemotherapy-induced allodynia. These studies also provide in-sight into the biological mechanism behind the therapeutic utility of cannabis compounds in managing chemotherapy-induced neuropathic pain, and provide a basis for the conduct of future clinical studies in patients of this population.”

Associations between medical cannabis and prescription opioid use in chronic pain patients: A preliminary cohort study.

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“Current levels and dangers of opioid use in the U.S. warrant the investigation of harm-reducing treatment alternatives.

PURPOSE:

A preliminary, historical, cohort study was used to examine the association between enrollment in the New Mexico Medical Cannabis Program (MCP) and opioid prescription use.

RESULTS:

By the end of the 21 month observation period, MCP enrollment was associated with 17.27 higher age- and gender-adjusted odds of ceasing opioid prescriptions (CI 1.89 to 157.36, p = 0.012), 5.12 higher odds of reducing daily prescription opioid dosages (CI 1.56 to 16.88, p = 0.007), and a 47 percentage point reduction in daily opioid dosages relative to a mean change of positive 10.4 percentage points in the comparison group (CI -90.68 to -3.59, p = 0.034). The monthly trend in opioid prescriptions over time was negative among MCP patients (-0.64mg IV morphine, CI -1.10 to -0.18, p = 0.008), but not statistically different from zero in the comparison group (0.18mg IV morphine, CI -0.02 to 0.39, p = 0.081). Survey responses indicated improvements in pain reduction, quality of life, social life, activity levels, and concentration, and few side effects from using cannabis one year after enrollment in the MCP (ps<0.001).

CONCLUSIONS:

The clinically and statistically significant evidence of an association between MCP enrollment and opioid prescription cessation and reductions and improved quality of life warrants further investigations on cannabis as a potential alternative to prescription opioids for treating chronic pain.” https://www.ncbi.nlm.nih.gov/pubmed/29145417

“In summary, if cannabis can serve as an alternative to prescription opioids for at least some patients, legislators and the medical community may want to consider medical cannabis programs as a potential tool for combating the current opioid epidemic.”   http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0187795

“Study finds medical cannabis is effective at reducing opioid addiction”  http://news.unm.edu/news/study-finds-medical-cannabis-is-effective-at-reducing-opioid-addiction

Availability and approval of cannabis-based medicines for chronic pain management and palliative/supportive care in Europe: A survey of the status in the chapters of the European Pain Federation.

European Journal of Pain

“There is considerable public and political interest in the use of cannabis products for medical purposes.

METHODS:

The task force of the European Pain Federation (EFIC) conducted a survey with its national chapters representatives on the status of approval of all types of cannabis-based medicines, the covering of costs and the availability of a position paper of a national medical association on the use of medical cannabis for chronic pain and for symptom control in palliative/supportive care.

RESULTS:

Thirty-one out of 37 contacted councillors responded. Plant-derived tetrahydrocannabinol/cannabidiol (THC/CBD) oromucosal spray is approved for spasticity in multiple sclerosis refractory to conventional treatment in 21 EFIC chapters. Plant-derived THC (dronabinol) is approved for some palliative care conditions in four EFIC chapters. Synthetic THC analogue (nabilone) is approved for chemotherapy-associated nausea and vomiting refractory to conventional treatment in four EFIC chapters’. Eight EFIC chapters’ countries have an exceptional and six chapters an expanded access programme for medical cannabis. German and Israeli pain societies recommend the use of cannabis-based medicines as third-line drug therapies for chronic pain within a multicomponent approach. Conversely, the German medical association and a team of finish experts and officials do not recommend the prescription of medical cannabis due to the lack of high-quality evidence of efficacy and the potential harms.

CONCLUSIONS:

There are marked differences between the countries represented in EFIC in the approval and availability of cannabis-based products for medical use. EFIC countries are encouraged to collaborate with the European Medicines Agency to publish a common document on cannabis-based medicines.

SIGNIFICANCE:

There are striking differences between European countries in the availability of plant-derived and synthetic cannabinoids and of medical cannabis for pain management and for symptom control in palliative care and in the covering of costs by health insurance companies or state social security systems.”

https://www.ncbi.nlm.nih.gov/pubmed/29134767

http://onlinelibrary.wiley.com/doi/10.1002/ejp.1147/abstract

Cannabinoids offer alternatives to opioids for pain relief, experts say.

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“Alternatives to opioids can be used alone or in combination with opioids for pain relief, to help prevent medical exposure to narcotics being an entry point to misuse, said experts at a medical education forum in Washington, DC on 3 November.

Endocannabinoid compounds found in marijuana can greatly enhance the potency of opioids in relieving pain.

The synergy from using these drugs together can result in more effective pain relief from lower doses of opioids,”

https://www.ncbi.nlm.nih.gov/pubmed/29113969

http://www.bmj.com/content/359/bmj.j5140.full