Category Archives: Chronic Inflammatory and Neuropathic Pain

Edible cannabis for chronic low back pain: associations with pain, mood, and intoxication

Posted on by
Reply
pubmed logo

“Introduction: Cannabis, commonly known for both therapeutic and intoxicating effects, is gaining accessibility on legal markets and traction as a potential alternative therapy for pain mediation, particularly in those suffering from chronic low back pain. However, the effectiveness in this population of legal market forms of cannabis, particularly commonly used edibles, is unknown.

Methods: Therefore, this study utilized a naturalistic prospective design where participants with chronic low back pain with intentions to initiate cannabis use for treatment were recruited and self-selected edible cannabis products containing varying amounts of delta- 9 tetrahydrocannabinol (THC) and cannabidiol (CBD). Products were categorized as CBD-dominant, THC-dominant, or combined THC and CBD (THC + CBD).

Results: 249 participants [140 female (56.62%), mean (SD) age of 46.30 (16.02), 90% White] were tracked over 2 weeks of ad libitum use and assessed during a naturalistic acute cannabis administration session on changes in pain, mood, and subjective drug effects. During acute administration, a significant correlation between THC dose and short-term pain relief was found, suggesting that higher THC doses were associated with greater pain reduction (p < .05). In addition, THC was associated with higher levels of subjective cannabis drug effects (p < .001), regardless of whether CBD was also in the edible product. Acute CBD dose was primarily associated with short-term tension relief (p < .05); however, there were no associations between CBD dose and acute pain. Over the 2-week ad libitum administration period results suggested pain reductions across participants using all forms of cannabis. However, trends suggested that more frequent use of CBD-dominant edible cannabis may be associated with greater reductions in perceived pain over the 2-week observation period (p = .07).

Discussion: These findings support the short-term analgesic effects of THC and anxiolytic effects of CBD and further suggest that orally-administered THC and CBD should continue to be evaluated for the potential to provide both acute and extended relief from chronic low back pain.”

https://pubmed.ncbi.nlm.nih.gov/39380911/

“In this naturalistic observational study, it was found that the use of edible cannabinoid products significantly reduced chronic pain in extended and acute use models. More specifically, THC dose was associated with the greatest decrease in pain during the acute use session. Further, there was signal that more frequent use of a CBD-dominant product may provide stronger relief over a 2-week ad libitum use period.

These results indicate that edible cannabis may be a safe and suitable alternative pain therapy for those looking to substitute more traditional pain medications.”

https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2024.1464005/full

Identification of the TRPA1 Cannabinoid-Binding Site

Posted on by
Reply
pubmed logo

“Chronic pain accounts for nearly two-thirds of conditions eligible for medical cannabis licenses, yet the mechanisms underlying cannabis-induced analgesia remain poorly understood.

The principal phytocannabinoids, the psychoactive Δ9-tetrahydrocannabinol (THC) and non-psychoactive cannabidiol (CBD), exhibit comparable efficacy in pain management. Notably, THC functions as an agonist of cannabinoid receptor 1 (CB1), whereas CBD shows minimal activity on CB1 and CB2 receptors.

Elucidating the molecular targets through which phytocannabinoids modulate the pain system is required for advancing our understanding of the pain pathway and optimizing medical cannabis therapies.

Transient receptor potential ankyrin 1 (TRPA1), a pivotal chemosensor in the pain pathway, has been identified as a phytocannabinoid target. Unlike most TRPA1 activators, phytocannabinoid activation is not mediated through the electrophilic binding site, suggesting an alternative mechanism. Here, we identified the human TRPA1 channel cannabinoid-binding site (CBS) and demonstrated that mutations at residue Y840 abolished responses to both THC and CBD at saturating concentrations, indicating a shared primary binding site. Molecular modeling revealed distinct interactions of THC and CBD with the Y840 residue within the CBS. Additionally, CBD binds to the adjacent general anesthetic binding site at oversaturating concentrations.

Our findings define the CBS of TRPA1 as overlapping with and adjacent to binding sites for other allosteric activators, suggesting that TRPA1 possesses a highly adaptable domain for binding non-electrophilic activators. This underscores its unique role as a chemosensor in the pain pathway. Furthermore, our results provide new insights into the molecular mechanisms of cannabinoid-induced analgesia and identify novel targets for pain management therapies.”

https://pubmed.ncbi.nlm.nih.gov/39368566/

https://www.sciencedirect.com/science/article/pii/S104366182400389X?via%3Dihub

Cannabis sativa L. Extract Alleviates Neuropathic Pain and Modulates CB1 and CB2 Receptor Expression in Rat

Posted on by
Reply
pubmed logo

“Introduction: Cannabis sativa L. (CSL) extract has pain-relieving potential due to its cannabinoid content, so the effects of two CSL extracts on alleviating neuropathic pain were investigated in vivo. Methods and groups: Male Wistar rats (n = 130) were divided into groups and received vincristine (0.1 mg/kg) and gabapentin (60 mg/kg) to induce and relieve neuropathic pain or CSL extracts (D and B). The mRNA and protein expression of the cannabinoid receptors type 1 and 2 (CB1R, CB2R) were evaluated in the cerebral cortex, hippocampus, and lymphocytes. Behavioural tests (Tail-Flick and von Frey) were performed on all animals.

Results: VK-induced neuropathic pain was accompanied by decreased CB1R protein level and CB2R mRNA expression in the cortex. Gabapentin relieved pain and increased CB1R protein levels in the hippocampus compared to the vincristine group. Hippocampus CB1R protein expression increased with the administration of extract D (10 mg/kg, 40 mg/kg) and extract B (7.5 mg/kg, 10 mg/kg) compared to VK group. In the cerebral cortex CSL decreased CB1R protein expression (10 mg/kg, 20 mg/kg, 40 mg/kg of extract B) and mRNA level (5 mg/kg, 7.5 mg/kg of extract B; 20 mg/kg of extract D) compared to the VK-group.CB2R protein expression increased in the hippocampus after treatment with extract B (7.5 mg/kg) compared to the VK-group. In the cerebral cortex extract B (10 mg/kg, 20 mg/kg) increased CB2R protein expression compared to VK-group.

Conclusion: Alterations in cannabinoid receptor expression do not fully account for the observed behavioural changes in rats. Therefore, additional signalling pathways may contribute to the initiation and transmission of neuropathic pain. The Cannabis extracts tested demonstrated antinociceptive effects comparable to gabapentin, highlighting the antinociceptive properties of Cannabis extracts for human use.”

https://pubmed.ncbi.nlm.nih.gov/39334832/

“Furthermore, both tested Cannabis sativa L. extracts demonstrated antinociceptive effects comparable to gabapentin, highlighting the potential medical value of Cannabis extracts for human use.”

https://www.mdpi.com/2218-273X/14/9/1065

Cannabinoids as a Natural Alternative for the Management of Neuropathic Pain: A Systematic Review of Randomized Placebo-Controlled Trials

Posted on by
Reply

“Dysfunction or damage to the nervous system may develop into and result in a chronic pain condition known as neuropathic pain. Neuropathic pain is defined as the structural and functional alteration of the somatosensory component of the nervous system. The treatment of neuropathic pain is a complex endeavor, which often requires specialist care and intensive drug therapy. Recently, cannabinoids have emerged as an alternative and natural option for the treatment of chronic pain, with tetrahydrocannabinol (THC) and cannabidiol (CBD) being the most extensively studied neuroactive components. The therapeutic potential of cannabis remains largely underexplored, primarily due to its social stigma and the restrictions that are in place on its cultivation. The primary aim of this systematic review was to explore the therapeutic value of cannabinoids in the management of chronic pain and thus achieve an improved quality of life for those patients.

A systematic review of the literature published over the last two decades was performed using the following databases: PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Turning research into practice (Trip), and Google Scholar. Studies that were completed and published between January 01, 2000 and August 31, 2024, in English language, were extracted and appraised. A combination of keywords and Boolean operators Cannabis OR Chronic Pain OR End of life OR Pain Management AND Drug therapy was employed for data extraction. The Cochrane risk-of-bias tool for randomized trials (RoB 2) was used for risk-of-bias assessment. The initial search resulted in 125282 articles; 86,781 of the articles were identified as duplicates and were removed from the primary analysis, and 38,501 abstracts were thus screened. Abstracts, case studies, reports, editorials, viewpoints, cross-sectional studies, cohort studies, case-control studies, case series, and letters to the editor/correspondence manuscripts (n =38,492) were furthermore excluded. Nine full-text articles were critically assessed and tested against the inclusion and exclusion criteria, and a further four articles were excluded with a total of five placebo-controlled randomized control studies being ultimately included in the final systematic review.

Compared to placebo, cannabinoids provided significant relief from chronic pain (33% vs 15%) as measured by the visual analog scale. The transdermal application of CBD led to a more pronounced reduction in sharp pain, according to the neuropathic pain scale. Minimal to no side effects were recorded, further highlighting the potential benefits of cannabinoids. 

The potential benefit of cannabinoids is that they are naturally derived drugs that have already been shown to have the potential to effectively decrease chronic pain with minimal side effects as compared to the standard drugs being used. The ability of cannabinoids to provide pain relief with minimal side effects and concurrently be a naturally derived product may potentially be a life-changing alternative that the pharmaceutical market is in dire need of.”

https://www.cureus.com/articles/297124-cannabinoids-as-a-natural-alternative-for-the-management-of-neuropathic-pain-a-systematic-review-of-randomized-placebo-controlled-trials#!/

The endocannabinoid system as a therapeutic target in neuropathic pain: a review

Posted on by
Reply
pubmed logo

“Introduction: This review highlights the critical role of the endocannabinoid system (ECS) in regulating neuropathic pain and explores the therapeutic potential of cannabinoids. Understanding the mechanisms of the ECS, including its receptors, endogenous ligands, and enzymatic routes, can lead to innovative treatments for chronic pain, offering more effective therapies for neuropathic conditions. This review bridges the gap between preclinical studies and clinical applications by emphasizing ECS modulation for better pain management outcomes.

Areas covered: A review mapped the existing literature on neuropathic pain and the effects of modulating the ECS using natural and synthetic cannabinoids. This analysis examined ECS components and their alterations in neuropathic pain, highlighting the peripheral, spinal, and supraspinal mechanisms. This review aimed to provide a thorough understanding of the therapeutic potential of cannabinoids in the management of neuropathic pain.

Expert opinion: Advances in cannabinoid research have shown significant potential for the management of chronic neuropathic pain. The study emphasizes the need for high-quality clinical trials and collaborative efforts among researchers, clinicians, and regulatory bodies to ensure safe and effective integration of cannabinoids into pain management protocols. Understanding the mechanisms and optimizing cannabinoid formulations and delivery methods are crucial for enhancing therapeutic outcomes.”

https://pubmed.ncbi.nlm.nih.gov/39317147/

“Research on the modulation of the endocannabinoid system in nervous tissue related to neuropathic pain reveals complex mechanisms of pain modulation. Dysregulation of the endocannabinoid system, microglial activation, and interactions between various signaling pathways contribute to the onset and persistence of neuropathic pain. Understanding these molecular and cellular processes is crucial for developing targeted therapies that leverage the endocannabinoid system to alleviate neuropathic pain.”

https://www.tandfonline.com/doi/full/10.1080/14728222.2024.2407824

“Smoked Cannabis Proven Effective In Treating Neuropathic Pain”

https://www.sciencedaily.com/releases/2007/10/071024141745.htm

THC vapor inhalation attenuates hyperalgesia in rats using a chronic inflammatory pain model

Posted on by
Reply
pubmed logo

“Humans use cannabinoid drugs to alleviate pain.

As cannabis and cannabinoids are legalized in the U.S. for medicinal and recreational use, it has become critical to determine the potential utilities and harms of cannabinoid drugs in individuals living with chronic pain.

Here, we tested the effects of repeated THC vapor inhalation on thermal nociception and mechanical sensitivity, in adult male and female Wistar rats using a chronic inflammatory pain model (i.e., treated with Complete Freund’s Adjuvant [CFA]).

We report that repeated THC vapor inhalation rescues thermal hyperalgesia in males and females treated with CFA, and also reduces mechanical hypersensitivity in CFA males but not females. Many of the anti-hyperalgesic effects of chronic THC vapor were still observable 24 hours after cessation of the last THC exposure.

We also report plasma levels of THC and its major metabolites, some of which are cannabinoid type-1 receptor (CB1) agonists, after the first and tenth days of THC vapor inhalation. Finally, we report that systemic administration of the CB1 inverse agonist AM251 (1mg/kg; i.p.) blocks the anti-hyperalgesic effects of THC vapor in males and females.

These data provide a foundation for future work that will explore the cells and circuits underlying the anti-hyperalgesic effects of THC vapor inhalation in individuals with chronic inflammatory pain.

PERSPECTIVE: Cannabinoids are thought to have potential utility in the treatment of chronic pain, but few animal studies have tested the effects of chronic THC or cannabis in animal models of chronic pain. We tested the effects of repeated THC vapor inhalation on chronic pain-related outcomes in male and female animals.”

https://pubmed.ncbi.nlm.nih.gov/39121915/

https://www.jpain.org/article/S1526-5900(24)00599-6/abstract

Analgesic properties of next generation modulators of endocannabinoid signaling: leveraging modern tools for the development of novel therapeutics

Posted on by
Reply
pubmed logo

“Targeting the endocannabinoid (eCB) signaling system for pain relief is an important treatment option that is only now beginning to be mechanistically explored.

In this review, we focus on two recently appreciated cannabinoid-based targeting strategies, treatments with cannabidiol (CBD) and a/b-hydrolase domain containing 6 (ABHD6) inhibitors, which have the exciting potential to produce pain relief through distinct mechanisms of action (MOA) and without intoxication.

We review evidence on plant-derived cannabinoids for pain, with an emphasis on CBD and its multiple molecular targets expressed in pain pathways. We also discuss the function of eCB signaling in regulating pain responses and the therapeutic promises of inhibitors targeting ABHD6, a 2-arachidonoylglycerol (2-AG) hydrolyzing enzyme. Finally, we discuss how the novel cannabinoid biosensor, GRABeCB2.0, may be leveraged to enable the discovery of targets modulated by cannabinoids at a circuit-specific level. 

Significance Statement Cannabis has been used by humans as an effective medicine for millennia, including for pain management. Recent evidence emphasizes the therapeutic potential of compounds that modulate endocannabinoid signaling. Specifically, cannabidiol and inhibitors of the enzyme ABHD6 represent promising strategies to achieve pain relief by modulating endocannabinoid signaling in pain pathways via distinct, non-intoxicating, mechanisms of action.”

https://pubmed.ncbi.nlm.nih.gov/39060165/

https://jpet.aspetjournals.org/content/early/2024/07/26/jpet.124.002119

Cannabidiol and Beta-Caryophyllene Combination Attenuates Diabetic Neuropathy by Inhibiting NLRP3 Inflammasome/NFκB through the AMPK/sirT3/Nrf2 Axis

Posted on by
Reply
pubmed logo

“Background: In this study, we investigated in detail the role of cannabidiol (CBD), beta-caryophyllene (BC), or their combinations in diabetic peripheral neuropathy (DN). The key factors that contribute to DN include mitochondrial dysfunction, inflammation, and oxidative stress.

Methods: Briefly, streptozotocin (STZ) (55 mg/kg) was injected intraperitoneally to induce DN in Sprague-Dawley rats, and we performed procedures involving Randall Sellito calipers, a Von Frey aesthesiometer, a hot plate, and cold plate methods to determine mechanical and thermal hyperalgesia in vivo. The blood flow to the nerves was assessed using a laser Doppler device. Schwann cells were exposed to high glucose (HG) at a dose of 30 mM to induce hyperglycemia and DCFDA, and JC1 and Mitosox staining were performed to determine mitochondrial membrane potential, reactive oxygen species, and mitochondrial superoxides in vitro. The rats were administered BC (30 mg/kg), CBD (15 mg/kg), or combination via i.p. injections, while Schwann cells were treated with 3.65 µM CBD, 75 µM BC, or combination to assess their role in DN amelioration.

Results: Our results revealed that exposure to BC and CBD diminished HG-induced hyperglycemia in Schwann cells, in part by reducing mitochondrial membrane potential, reactive oxygen species, and mitochondrial superoxides. Furthermore, the BC and CBD combination treatment in vivo could prevent the deterioration of the mitochondrial quality control system by promoting autophagy and mitochondrial biogenesis while improving blood flow. CBD and BC treatments also reduced pain hypersensitivity to hyperalgesia and allodynia, with increased antioxidant and anti-inflammatory action in diabetic rats. These in vivo effects were attributed to significant upregulation of AMPK, sirT3, Nrf2, PINK1, PARKIN, LC3B, Beclin1, and TFAM functions, while downregulation of NLRP3 inflammasome, NFκB, COX2, and p62 activity was noted using Western blotting.

Conclusions: the present study demonstrated that STZ and HG-induced oxidative and nitrosative stress play a crucial role in the pathogenesis of diabetic neuropathy. We find, for the first time, that a CBD and BC combination ameliorates DN by modulating the mitochondrial quality control system.”

https://www.mdpi.com/2227-9059/12/7/1442

“In summary, the present studies demonstrated that STZ- and HG-induced oxidative and nitrosative stress play a crucial role in the pathogenesis of diabetic neuropathy. The functional, behavioral, and molecular deficits were due to oxidant-induced damage, neuroinflammation, and bioenergetic deficits. These pathological consequences of nerve injury have been attenuated by the combination of CBD and BC in vitro and in vivo.

Our findings suggest that the enhanced neuroprotective effects of combination therapy may be attributable to simultaneous inhibition of oxidative stress, neuroinflammation, and NLRP3, as well as activation of Nrf2. Hence, the combination therapy could be suggested as a potential strategy that can be further pursued for the management of STZ- and HG-induced diabetic neuropathy.”

https://pubmed.ncbi.nlm.nih.gov/39062016/

Cannabidiol and pain

Posted on by
Reply
pubmed logo

“Chronic pain presents significant personal, psychological, and socioeconomic hurdles, impacting over 30% of adults worldwide and substantially contributing to disability. Unfortunately, current pharmacotherapy often proves inadequate, leaving fewer than 70% of patients with relief. This shortfall has sparked a drive to seek alternative treatments offering superior safety and efficacy profiles.

Cannabinoid-based pharmaceuticals, notably cannabidiol (CBD), hold promise in pain management, driven by their natural origins, versatility, and reduced risk of addiction. As we navigate the opioid crisis, ongoing research plunges into CBD’s therapeutic potential, buoyed by animal studies revealing its pain-relieving prowess through various system tweaks. However, the efficacy of cannabis in chronic pain management remains a contentious and stigmatized issue.

The International Association for the Study of Pain (IASP) presently refrains from endorsing cannabinoid use for pain relief. Nevertheless, evidence indicates their potential in alleviating cancer-related, neuropathic, arthritis, and musculoskeletal pain, necessitating further investigation. Crucially, our comprehension of CBD’s role in pain management is a journey still unfolding, with animal studies illustrating its analgesic effects through interactions with the endocannabinoid, inflammatory, and nociceptive systems.

As the plot thickens, it’s clear: the saga of chronic pain and CBD’s potential offers a compelling narrative ripe for further exploration and understanding.”

https://pubmed.ncbi.nlm.nih.gov/39029988/

https://www.sciencedirect.com/science/article/abs/pii/S0074774224000680?via%3Dihub

Select Minor Cannabinoids from Cannabis sativa are Cannabimimetic and Antinociceptive in a Mouse Model of Chronic Neuropathic Pain

Posted on by
Reply
pubmed logo

“Chronic pain conditions affect nearly 20% of the population in the United States. Current medical interventions, such as opioid drugs, are effective at relieving pain but are accompanied by many undesirable side effects. This is one reason increased numbers of chronic pain patients have been turning to Cannabis for pain management. 

Cannabis contains many bioactive chemical compounds; however, current research looking into lesser-studied minor cannabinoids in Cannabis lacks uniformity between experimental groups and/or excludes female mice from investigation. This makes it challenging to draw conclusions between experiments done with different minor cannabinoid compounds between labs or parse out potential sex differences that could be present.

We chose five minor cannabinoids found in lower quantities within Cannabis: cannabinol (CBN), cannabidivarin (CBDV), cannabigerol (CBG), Δ8-tetrahydrocannabinol (Δ8-THC), and Δ9-tetrahydrocannabivarin (THCV). These compounds were then tested for their cannabimimetic and pain-relieving behaviors in a cannabinoid tetrad assay and a chemotherapy-induced peripheral neuropathy (CIPN) pain model in male and female CD-1 mice.

We found that the minor cannabinoids we tested differed in the cannabimimetic behaviors evoked, as well as the extent. We found that CBN, CBG, and high dose Δ8-THC evoked some tetrad behaviors in both sexes, while THCV and low dose Δ8-THC exhibited cannabimimetic tetrad behaviors only in females. Only CBN efficaciously relieved CIPN pain, which contrasts with reports from other researchers. Together these findings provide further clarity to the pharmacology of minor cannabinoids and suggest further investigation into their mechanism and therapeutic potential. 

Significance Statement Minor cannabinoids are poorly studied ligands present in lower levels in Cannabis than cannabinoids like THC. In this study we evaluated 5 minor cannabinoids (CBN, CBDV, CBG, THCV, and Δ8-THC) for their cannabimimetic and analgesic effects in mice. We found that 4 of the 5 minor cannabinoids showed cannabimimetic activity, while one was efficacious in relieving chronic neuropathic pain. This work is important in further evaluating the activity of these drugs, which are seeing wider public use with marijuana legalization.”

https://pubmed.ncbi.nlm.nih.gov/38834356/

https://jpet.aspetjournals.org/content/early/2024/06/04/jpet.124.002212