Category Archives: Neuropathic Pain

Insights on cannabidiol’s antiallodynic and anxiolytic mechanisms of action in a model of neuropathic pain

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PAIN Impact Factor Increase to 6.029 - IASP“Recent studies have shown that cannabidiol (CBD) could have a great therapeutic potential for treating disorders such as chronic pain and anxiety. In the target article, the authors propose that CBD modulates serotonergic transmission and reverses allodynia and anxiety-like behaviour in a rat model of neuropathic pain. Furthermore, this study shows an antinociceptive effect mediated by TRPV1 and partially by 5-HT1A receptors, as well as an anxiolytic effect mediated by 5-HT1A receptors.”

https://pubmed.ncbi.nlm.nih.gov/32766463/

https://journals.lww.com/painrpts/Fulltext/2019/10000/Insights_on_cannabidiol_s_antiallodynic_and.10.aspx

“Cannabidiol modulates serotonergic transmission and reverses both allodynia and anxiety-like behavior in a model of neuropathic pain”  https://pubmed.ncbi.nlm.nih.gov/30157131/

 

Spinal cannabinoid CB1 or CB2 receptors activation attenuates mechanical allodynia in streptozotocin-induced diabetic rats

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 Behavioural Pharmacology“Diabetes is a chronic disease associated with a high number of complications such as peripheral neuropathy, which causes sensorial disturbances and may lead to the development of diabetic neuropathic pain (DNP). The current treatment for DNP is just palliative and the drugs may cause severe adverse effects, leading to discontinuation of treatment. Thus, new therapeutic targets need to be urgently investigated.

Studies have shown that cannabinoids have promising effects in the treatment of several pathological conditions, including chronic pain.

Thus, we aimed to investigate the acute effect of the intrathecal injection of CB1 or CB2 cannabinoid receptor agonists N-(2-chloroethyl)-5Z, 8Z, 11Z, 14Z-eicosatetraenamide (ACEA) or JWH 133, respectively (10, 30 or 100 μg/rat) on the mechanical allodynia associated with experimental diabetes induced by streptozotocin (60 mg/kg; intraperitoneal) in rats.

Cannabinoid receptor antagonists CB1 AM251 or CB2 AM630 (1 mg/kg) were given before treatment with respective agonists to confirm the involvement of cannabinoid CB1 or CB2 receptors. Rats with diabetes exhibited a significant reduction on the paw mechanical threshold 2 weeks after diabetes induction, having the maximum effect observed 4 weeks after the streptozotocin injection. This mechanical allodynia was significantly improved by intrathecal treatment with ACEA or JWH 133 (only at the higher dose of 100 μg). Pre-treatment with AM251 or AM630 significantly reverted the anti-allodynic effect of the ACEA or JWH 133, respectively.

Considering the clinical challenge that the treatment of DPN represents, this study showed for the first time, that the intrathecal cannabinoid receptors agonists may represent an alternative for the treatment of DNP.”

https://pubmed.ncbi.nlm.nih.gov/32804775/

Protective role of neuronal and lymphoid cannabinoid CB 2 receptors in neuropathic pain

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 eLife logo“Cannabinoid CB2 receptor (CB2) agonists are potential analgesics void of psychotropic effects.

Peripheral immune cells, neurons and glia express CB2, however the involvement of CB2 from these cells in neuropathic pain remains unresolved. We explored spontaneous neuropathic pain through on-demand self-administration of the selective CB2 agonist JWH133 in wild-type and knockout mice lacking CB2 in neurons, monocytes or constitutively. Operant self-administration reflected drug-taking to alleviate spontaneous pain, nociceptive and affective manifestations. While constitutive deletion of CB2 disrupted JWH133-taking behavior, this behavior was not modified in monocyte-specific CB2 knockouts and was increased in mice defective in neuronal CB2 knockouts suggestive of increased spontaneous pain. Interestingly, CB2-positive lymphocytes infiltrated the injured nerve and possible CB2transfer from immune cells to neurons was found. Lymphocyte CB2depletion also exacerbated JWH133 self-administration and inhibited antinociception.

This work identifies a simultaneous activity of neuronal and lymphoid CB2that protects against spontaneous and evoked neuropathic pain.”

https://pubmed.ncbi.nlm.nih.gov/32687056/

https://elifesciences.org/articles/55582

The Therapeutic Effectiveness of Full Spectrum Hemp Oil Using a Chronic Neuropathic Pain Model

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life-logo“Few models exist that can control for placebo and expectancy effects commonly observed in clinical trials measuring ‘Cannabis’ pharmacodynamics. We used the Foramen Rotundum Inflammatory Constriction Trigeminal Infraorbital Nerve injury (FRICT-ION) model to measure the effect of “full-spectrum” whole plant extracted hemp oil on chronic neuropathic pain sensitivity in mice.

Results: Mechanical allodynia was alleviated within 1 h (d = 2.50, p < 0.001) with a peak reversal effect at 4 h (d = 7.21, p < 0.001) and remained significant throughout the 6 h observation window. There was no threshold change on contralateral whisker pad after hemp oil administration, demonstrating the localization of anesthetic response to affected areas.

Conclusion: Future research should focus on how whole plant extracted hemp oil affects multi-sensory and cognitive-attentional systems that process pain.

The present study shows for the first time that common, commercially available, and easily reproducible full-spectrum hemp oil induces significant anti-allodynic effects with a bell-shaped pain sensitivity effect peeking between 2 and 4 h and lasting over 6 h. The study provides evidence that phytochemical extracts of the Cannabis plant, even with relatively low levels of THC, can significantly improve mechanical pressure pain in animals with established chronic neuropathic hypersensitivity.”

https://www.mdpi.com/2075-1729/10/5/69/htm

“Legal Cannabis hemp oil effectively treats chronic neuropathic pain: study”   https://medicalxpress.com/news/2020-05-legal-cannabis-hemp-oil-effectively.html

Investigation of cannabidiol gastro retentive tablets based on regional absorption of cannabinoids in rats.

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European Journal of Pharmaceutics and Biopharmaceutics“The cannabis plant has been widely researched for many therapeutic indications and found to be effective in many chronic conditions such as epilepsy, neuropathic or chronic pain and more. However, biased opinion against compounds of the plant, regulatory as well as compounding challenges have led to very few approved medicinal products. Those formulations which are approved are dosed several times a day, creating an unmet need for controlled release (CR) formulations of cannabinoids. Conventional CR formulations rely on prolonged absorption including the colon. The purpose of this work is to investigate regional absorption of major cannabinoids THC and CBD from the colon and develop a suitable CR formulation. As hypothesized by researchers, THC and CBD have poor absorption from the colon compared to small intestine, suggesting that these compounds have a narrow absorption window. The suggested formulation examined in-vitro was a floating gastro retentive tablet based on egg albumin matrix, gas generating agents and surfactants. In-vivo investigation of CBD containing formulation in the freely moving rat model proved a prolonged absorption phase with a substantial increase in bioavailability compared to CBD solution. The findings of this paper answer a crucial question regarding potential application of CR dosage forms for cannabinoids and shed light on the regional intestinal absorption of these compounds. Ultimately, these results cement the way for future development of cannabinoid gastro retentive dosage forms.”

https://www.ncbi.nlm.nih.gov/pubmed/32422168

https://www.sciencedirect.com/science/article/abs/pii/S0939641120301375?via%3Dihub

Novel approaches and current challenges with targeting the endocannabinoid system.

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 Publication Cover“The pathophysiological relevance of the endocannabinoid system has been widely demonstrated in a variety of diseases including cancer, neurological disorders, and metabolic issues. Therefore, targeting the receptors and the endogenous machinery involved in this system can provide a successful therapeutic outcome.

Ligands targeting the canonical cannabinoid receptors, CB1 and CB2, along with inhibitors of the endocannabinoid enzymes have been thoroughly studied in diverse disease models. In fact, phytocannabinoids such as cannabidiol or Δ9-tetrahydrocannabinol are currently on the market for the management of neuropathic pain due to spasticity in multiple sclerosis or seizures in children epilepsy amongst others.

Expert opinion: Even if orthosteric CB1 and CB2 ligands are on the forefront in cannabinoid clinical research, emerging strategies such as allosteric or biased modulation of these receptors along with controlled off-targets effects may increase the therapeutic potential of cannabinoids.”

https://www.ncbi.nlm.nih.gov/pubmed/32336154

“Multi-target approaches could be promising strategies for the treatment of endocannabinoid system-related disorders. The authors believe that phytocannabinoids are at the forefront of future clinical research.”

https://www.tandfonline.com/doi/abs/10.1080/17460441.2020.1752178?journalCode=iedc20

The anti-inflammatory and analgesic effects of formulated full-spectrum cannabis extract in the treatment of neuropathic pain associated with multiple sclerosis.

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 SpringerLink“Cannabis has been used for thousands of years in many cultures for the treatment of several ailments including pain.

The benefits of cannabis are mediated largely by cannabinoids, the most prominent of which are tetrahydrocannabinol (THC) and cannabidiol (CBD). As such, THC and/or CBD have been investigated in clinical studies for the treatment of many conditions including neuropathic pain and acute or chronic inflammation.

While a plethora of studies have examined the biochemical effects of purified THC and/or CBD, only a few have focused on the effects of full-spectrum cannabis plant extract. Accordingly, studies using purified THC or CBD may not accurately reflect the potential health benefits of full-spectrum cannabis extracts.

Indeed, the cannabis plant produces a wide range of cannabinoids, terpenes, flavonoids, and other bioactive molecules which are likely to contribute to the different biological effects. The presence of all these bioactive molecules in cannabis extracts has garnered much attention of late especially with regard to their potential role in the treatment of neuropathic pain associated with multiple sclerosis.:

Herein, the current knowledge about the potential beneficial effects of existing products of full-spectrum cannabis extract in clinical studies involving patients with multiple sclerosis is extensively reviewed. In addition, the possible adverse effects associated with cannabis use is discussed along with how the method of extraction and the delivery mechanisms of different cannabis extracts contribute to the pharmacokinetic and biological effects of full-spectrum cannabis extracts.”

https://www.ncbi.nlm.nih.gov/pubmed/32239248

https://link.springer.com/article/10.1007%2Fs00011-020-01341-1

The molecular mechanisms that underpin the biological benefit of full spectrum cannabis extract in the treatment of neuropathic pain and inflammation.

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Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease“Cannabis has been shown to be beneficial in the treatment of pain and inflammatory diseases.

The biological effect of cannabis is mainly attributed to two major cannabinoids, tetrahydrocannabinol and cannabidiol. In the majority of studies to-date, a purified tetrahydrocannabinol and cannabidiol alone or in combination have been extensively examined in many studies for the treatment of numerous disorders including pain and inflammation. However, few studies have investigated the biological benefits of full-spectrum cannabis plant extract.

Given that cannabis is known to generate a large number of cannabinoids along with numerous other biologically relevant products including terpenes, studies involving purified tetrahydrocannabinol and/or cannabidiol may not precisely consider the potential biological benefits of the full-spectrum cannabis extracts. This may be especially true in the role of cannabis as a treatment of pain and inflammation. Herein, we review the pre-clinical physiological and molecular mechanisms in biological systems that are affected by cannabis.”

https://www.ncbi.nlm.nih.gov/pubmed/32201189

“Full-spectrum cannabis extract demonstrates several convincing beneficial anti-inflammatory and analgesic effects in preclinical studies. Full-spectrum cannabis extract may represent a promising therapeutic agent that seems to benefit a variety of conditions associated with pain and inflammation.”

https://www.sciencedirect.com/science/article/abs/pii/S0925443920301162?via%3Dihub

Analgesic Effects of Cannabinoids for Chronic Non-cancer Pain: a Systematic Review and Meta-Analysis with Meta-Regression.

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SpringerLink “There is growing interest in using cannabinoids for chronic pain.

We performed a systematic review and meta-analysis of randomized controlled trials to evaluate the analgesic efficacy and adverse effects of cannabinoids for chronic non-cancer pain.

PubMed, EMBASE, Web of Science, Cochrane CENTRAL and clinicaltrials.gov were searched up to December 2018. Information on the type, dosage, route of administration, pain conditions, pain scores, and adverse events were extracted for qualitative analysis. Meta-analysis of analgesic efficacy was performed. Meta-regression was performed to compare the analgesic efficacy for different pain conditions (neuropathic versus non-neuropathic pain). Risk of bias was assessed by The Cochrane Risk of Bias tool, and the strength of the evidence was assessed using the Grade of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

Forty-three randomized controlled trials were included. Meta-analysis was performed for 33 studies that compared cannabinoids to placebo, and showed a mean pain score (scale 0-10) reduction of -0.70 (p < 0.001, random effect). Meta-regression showed that analgesic efficacy was similar for neuropathic and non-neuropathic pain (Difference = -0.14, p = 0.262).

Inhaled, oral, and oromucosal administration all provided statistically significant, but small reduction in mean pain score (-0.97, -0.85, -0.45, all p < 0.001). Incidence of serious adverse events was rare, and non-serious adverse events were usually mild to moderate. Heterogeneity was moderate.

The GRADE level of evidence was low to moderate. Pain intensity of chronic non-cancer patients was reduced by cannabinoids consumption, but effect sizes were small. Efficacy for neuropathic and non-neuropathic pain was similar.”

https://www.ncbi.nlm.nih.gov/pubmed/32172501

https://link.springer.com/article/10.1007%2Fs11481-020-09905-y

A Review of Scientific Evidence for THC:CBD Oromucosal Spray (Nabiximols) in the Management of Chronic Pain.

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“The 20% prevalence of chronic pain in the general population is a major health concern given the often profound associated impairment of daily activities, employment status, and health-related quality of life in sufferers. Resource utilization associated with chronic pain represents an enormous burden for healthcare systems. Although analgesia based on the World Health Organization’s pain ladder continues to be the mainstay of chronic pain management, aside from chronic cancer pain or end-of-life care, prolonged use of non-steroidal anti-inflammatory drugs or opioids to manage chronic pain is rarely sustainable.

As the endocannabinoid system is known to control pain at peripheral, spinal, and supraspinal levels, interest in medical use of cannabis is growing.

A proprietary blend of cannabis plant extracts containing delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) as the principal cannabinoids is formulated as an oromucosal spray (USAN name: nabiximols) and standardized to ensure quality, consistency and stability. This review examines evidence for THC:CBD oromucosal spray (nabiximols) in the management of chronic pain conditions.

Cumulative evidence from clinical trials and an exploratory analysis of the German Pain e-Registry suggests that add-on THC:CBD oromucosal spray (nabiximols) may have a role in managing chronic neuropathic pain, although further precise clinical trials are required to draw definitive conclusions.”

https://www.ncbi.nlm.nih.gov/pubmed/32104061

https://www.dovepress.com/a-review-of-scientific-evidence-for-thccbd-oromucosal-spray-nabiximols-peer-reviewed-article-JPR

“Smoked Cannabis Proven Effective In Treating Neuropathic Pain.” https://www.sciencedaily.com/releases/2007/10/071024141745.htm

“Marijuana Relieves Chronic Pain, Research Shows” https://www.webmd.com/pain-management/news/20100830/marijuana-relieves-chronic-pain-research-show#1