Cannabinoids and Pain: New Insights From Old Molecules

Cardiovascular Effects of Cannabinoids

Marijuana is now one of the most widely used substances in the United States that has been rising in prevalence given increasing legalization and recreational and medical usage. Despite its widespread use, there have been increasing concerns regarding the cardiovascular safety of marijuana. Recent studies have found a link between marijuana use and the development of cardiovascular disease. Most notably, marijuana has been found to be associated with various cardiac complications, including atherosclerosis, myocardial infarction, stroke, cardiomyopathy, arrhythmia, and arteritis. Given these growing concerns, this article seeks to examine the effects and significance of marijuana on cardiovascular health.

Marijuana Use Is Associated with Increased Rates of Hip Dislocation and Lower Insurance Reimbursement among Total Hip Arthroplasty Recipients

This study utilizes an all-payer database to compare 90-d and 1-year outcomes between marijuana and non-marijuana users undergoing total hip arthroplasty (THA). The primary aim of this study focused on 90-d and 1-year opioid consumption among marijuana users and non-users who underwent THA. Our secondary aim focused on comparing 90-d and 1-year rates of readmissions, revisions and adverse events between the two groups. A retrospective review was performed in the Mariner Database for all primary THA patients from 2010 to 2018. Marijuana users were identified utilizing International Classification of Diseases (ICD) 9 and 10 codes and matched 1:1 to non-marijuana users on age, sex, Charlson Comorbidity Index (CCI), obesity, alcohol, tobacco, illicit drug use, history of drug abuse, and presence of psychiatric history. This yielded a total of 1654 patients in each group. The 90-d and 1-year outcomes included opioid consumption, episode of care costs, readmissions, revisions, and complications. Chi-square was employed to assess categorical variables, while t-tests were employed for continuous variables. There was no difference in opioid consumption among marijuana users and non-marijuana users who underwent a THA. Marijuana use was associated with lower 90-d costs of care when compared with non-marijuana users. Marijuana users had higher rates of hip dislocation within 90 d and 1 year of surgery. Marijuana use is associated with higher 90-d and 1-year dislocation rates. THA recipients who use marijuana should be counseled concerning this increased risk. Prospective randomized control trials are needed to verify the results of this study.

A combination of peripherally restricted CB1 and CB2 cannabinoid receptor agonists reduces bladder afferent sensitisation in cystitis

Cannabinoid agonists can potentially ameliorate lower urinary tract symptoms (LUTS), including pain associated with interstitial cystitis/bladder pain syndrome (IC/BPS). This study aims to determine the contributions of the cannabinoid 1 receptors (CB1Rs) and CB2Rs in regulating the activity of different functional classes of afferents, comparing normal healthy bladder with bladders from guinea pigs with protamine/zymosan-induced cystitis. The mechanosensitivity of different functional afferent classes was determined by ex vivo single-unit extracellular recordings. Peripherally restricted CB1R preferential agonists, ACEA and PrNMI and peripherally restricted CB2R selective agonists, 4Q3C and olorinab all reduced the mechanosensitivity of mucosal bladder afferents. The potency and efficacy of these synthetic cannabinoid agonists were significantly increased in cystitis compared to controls. Combined application of CB1R agonists, ACEA or PrNMI with the CB2R agonist, 4Q3C produced additive inhibitory effects. ACEA and PrNMI also inhibited the stretch-induced firing of high-threshold muscular bladder afferents in animals with cystitis. In contrast, low- and high-threshold muscular-mucosal bladder afferents were unaffected by the CB1R and CB2R agonists in control and cystitis. Our data indicated that peripherally restricted CB1R and CB2R agonists effectively reduce the sensitisation of probable nociceptive afferents in the bladder in cystitis. The findings also suggest a potential benefit of simultaneously targeting both the CB1Rs and CB2Rs to ameliorate LUTS in cystitis.

Acute Kappa opioid receptor blocking disrupts the pro-cognitive effect of cannabidiol in neuropathic rats

Cannabidiol has been shown to ameliorate neuropathic pain and its affective components. Previous studies highlighted the pharmacological interaction between the CBD and opioid system, particularly the MOR, but the understanding of the interaction between CBD and kappa opioid receptor (KOR), physiologically stimulated by the endogenous opioid dynorphin, remains elusive. We assessed the pharmacological interactions between CBD and nor-BNI, a selective KOR antagonist in a rat neuropathic pain model. We show an increase in dynorphin peptide and its KOR receptors in the hippocampus' dentate gyrus (DG) of neuropathic rats showing allodynia, and memory deficits. Consistent with these findings, neuropathic pain was associated with long-term potentiation (LTP) impairment in the entorhinal cortex-DG, also referred to as the lateral perforant pathway (LPP). Moreover, a downregulation of the endocannabinoid 2-AG and an upregulation of the cannabinoid CB1 receptors in the DG were detected in neuropathic pain animals. Either an acute KOR antagonist administration or one-week CBD treatment normalized dynorphin levels and improved affective symptoms, LTP and receptor expression, whereas only CBD showed an anti-allodynic effect. In addition, CBD normalized the SNI-induced changes in neuroplasticity as well as endocannabinoid and GABA levels in the DG. Noteworthy, the acute blockade of the KOR carried out after CBD repeated administration causes the re-installment of some neuropathic condition symptoms. As a whole, these original results indicate a critical relationship between the adaptive changes in the hippocampus produced by CBD and the need to maintain the recovered physiological dynorphin tone to preserve the therapeutic effect of CBD in neuropathic rats.

Topical Cannabidiol for Established Chemotherapy-Induced Neuropathy: A Pilot Randomized Placebo-Controlled Trial

Background: Patients have been known to use cannabinoids for treating established chemotherapy-induced peripheral neuropathy (CIPN) based on anecdotal information and retrospective reports suggesting that such might be beneficial. In response, a double-blinded, placebo-controlled, randomized, pilot clinical trial was developed to evaluate whether resultant data would support a phase III trial for testing whether a cannabidiol (CBD) cream might improve CIPN. Methods: Forty patients with established CIPN were randomized, in a double-blinded manner, to topical CBD or a placebo cream. The study product was applied for 2 weeks, followed by a crossover for 2 weeks. Neuropathy was evaluated using the European Organization of Research and Treatment of Cancer (EORTC)-CIPN20, the Chemotherapy-Induced Peripheral Neuropathy Assessment Tool, and the Global Impression of Change instruments. Side effects were recorded by symptom diaries. Results: The EORTC-CIPN20 scores were similar in the patients receiving CBD versus the placebo. Likewise, the toxicity scores were similar in patients who received the CBD versus the placebo. Conclusions: This pilot trial did not support that the studied CBD isolate cream improved painful established CIPN. It was well tolerated overall. Clinical Trial Registration Number: NCT05388058.

Clinical guidance for cannabidiol-associated hepatotoxicity: A narrative review

There is increasing evidence that cannabidiol (CBD) use is associated with clinically significant liver enzyme (LE) elevations and drug-induced liver injury (DILI). The proportion of LE elevations and DILI events reported in the literature meet the Council for International Organizations of Medical Sciences' (CIOMS) classification of a common adverse drug reaction. However, these potential adverse events are unknown to many clinicians and may be overlooked. The increasing use of CBD for both medical and non-medical use necessitates clear direction in the diagnosis and management of CBD-associated hepatotoxicity. To our knowledge, no such clinical guidance currently exists. For people presenting with elevated LEs, CBD use should be screened for and be considered in the differential diagnosis. This narrative review will provide clinicians with guidance in the prevention, detection, and management of CBD-related hepatotoxicity.

Electroacupuncture Regulates Cannabinoid Receptor 1 Expression in a Mouse Fibromyalgia Model: Pharmacological and Chemogenetic Modulation

Fibromyalgia is a chronic illness usually accompanied by long-lasting, general pain throughout the body, often accompanied by anxiety, depression, fatigue, and sleep disruption. Meanwhile, doctors and scientists have not entirely discovered detailed mechanisms; patients always have an exaggerated sensation to pervasive pain without satisfied medical service. Given the lack of knowledge on its underlying mechanism, current treatments aim to provide pain and/or symptom relief. The present study aimed to clarify the role of cannabinoid receptor 1 (CB1) signaling in a mouse fibromyalgia pain model. To develop the mouse fibromyalgia model, mice were subjected to intermittent cold stress (ICS). Our results indicated that mechanical (2.09 ± 0.09 g) and thermal hyperalgesia (4.77 ± 0.29 s), which were evaluated by von Frey and Hargraves' tests, were induced by ICS, suggesting successful modeling. The hurting replies were then provoked by electroacupuncture (EA) but not for sham EA mice. Further, in a Western blot analysis, we found significantly decreased CB1 protein levels in the thalamus, somatosensory cortex, and anterior cingulate cortex. In addition, the levels of pain-related protein kinases and transcription factor were increased. Treatment with EA reliably increased CB1 expression in various brain regions sequentially alleviated by nociceptive mediators. Furthermore, the administration of a CB1 agonist significantly attenuated fibromyalgia pain, reversed EA analgesia by the CB1 antagonist, and further reversed the chemogenetic inhibition of SSC. Our innovative findings evidence the role of CB1 signaling in the interaction of EA and fibromyalgia, suggesting its potential for clinical trials and as a treatment target.

UK medical cannabis registry: A clinical outcome analysis of medical cannabis therapy in chronic pain patients with and without co-morbid sleep impairment

INTRODUCTION

Chronic pain (CP) affects 35.0%-51.3% of the UK population, with 67%-88% reporting sleep disturbances. Cannabis-based medicinal products (CBMPs) have shown therapeutic potential in managing CP. Evidence suggests poor sleep worsens pain perception; therefore, this study aimed to assess patient-reported outcome measures (PROMs) following CBMP treatment in CP patients with and without co-morbid sleep impairment.

METHODS

A prospective cohort study of CP patients from the UK Medical Cannabis Registry was conducted. Participants were separated by baseline single-item sleep quality scale (SQS) score into sleep impaired (SQS ≤3) and unimpaired (SQS ≥4) cohorts. The primary outcome assessed changes in PROMs from baseline to 1-, 3-, 6-, and 12-months. Participants completed the following: SQS, General Anxiety Disorder-7, EQ-5D-5L, Brief Pain Inventory (BPI), and Short-Form McGill Pain Questionnaire-2. Significance was defined as p < 0.050.

RESULTS

1139 participants met the inclusion criteria (sleep impaired: n = 517, 45.4%; sleep unimpaired: n = 622, 54.61%). The sleep impaired cohort showed improvements in all PROMs at each follow-up (p < 0.010). The sleep unimpaired cohort showed similar results (p < 0.050), except in SQS and ED-5Q-5L: self-care and anxiety/depression scores (p > 0.050). However, the sleep impaired cohort observed greater improvements in BPI pain severity (p < 0.050) and SQS (p < 0.001) than the sleep unimpaired cohort at all follow-ups. 2817 adverse events were self-reported between both cohorts (p = 0.197).

DISCUSSION

These findings align with literature that shows associated improvements in pain outcomes following CBMP administration. Sleep impaired individuals were more likely to experience greater pain severity improvements. However, this was not confirmed on multivariate logistic regression analysis and instead may be confounded by baseline pain severity.

CONCLUSION

Whilst these results show promise for the effects of CBMPs on CP, they must be examined within the limitations of the study design. These findings provide further evidence to support the design of subsequent randomized controlled trials to verify causality between CBMPs and pain outcomes.

Tribal Identity, Pain Interference, and Substance Use Among American Indian and Alaska Native Adolescents

Importance

Substance use is high among American Indian/Alaska Native adolescents. Pain interference is a risk factor for substance use, and identifying potential protective factors, such as Tribal identity, is important to help inform culturally grounded substance use prevention strategies.

Objective

To examine the protective potential of Tribal identity as a moderator in the association between pain interference and substance use in American Indian/Alaska Native adolescents.

Design, Setting, and Participants

This cross-sectional study of 10th-grade students self-identifying as American Indian/Alaska Native was conducted among students enrolled at 20 high schools on or near the Cherokee Nation Reservation. Data for this study were collected from the baseline assessments of a cluster randomized trial to prevent substance use among adolescents living on or near the Cherokee Nation Reservation. Inclusion criteria for high schools' participation included being located within counties that partially or fully fall within the Cherokee Nation reservation, a town population of 3000 individuals or fewer, and class sizes between 30 and 100 students. Exclusion criteria included high schools within metropolitan and micropolitan cores (per the US Census Bureau's Rural-Urban Commuting Area codes) and the existence of an established community drug prevention coalition. Student surveys were conducted from September 2021 to May 2024.

Exposure

Pain interference in the 7 days prior to baseline assessment.

Main Outcomes and Measures

The primary outcomes were past 30-day alcohol use, marijuana use, and prescription opioid misuse. Generalized estimating equations Poisson models were used, with an exchangeable correlation structure clustered on the school level using baseline data from a cluster randomized trial to prevent alcohol and substance use among adolescents. For each substance, a separate multivariable model was fit, which included pain interference, Tribal identity, an interaction term between pain interference and Tribal identity, age, gender, food insecurity, anxiety symptoms, and depressive symptoms.

Results

Among 514 self-identified American Indian/Alaska Native students at 20 high schools on or near the Cherokee Nation Reservation, mean (SD) participant age was 15.59 (0.62) years, and 252 participants (49.0%) self-identified as female. Pain interference was associated with alcohol use and prescription opioid misuse in American Indian/Alaska Native adolescents, controlling for age, gender, food insecurity, anxiety symptoms, and depressive symptoms. Tribal identity significantly moderated the association between pain interference and alcohol use (coefficient, -0.13; 95% CI, -0.23 to -0.02).

Conclusions and Relevance

When Tribal identity was high, the adverse association of pain interference with alcohol use was significantly attenuated. This demonstrates a protective role of Tribal identity on alcohol use, which can inform future substance use prevention efforts among American Indian/Alaska Native adolescents.

Trial Registration

ClinicalTrials.gov Identifier: NCT04839978.

The Elusive Truth of Cannabinoids for Rheumatic Pain

PURPOSE OF REVIEW

Medical cannabis (MC) has entered mainstream medicine by a unique route. Regulatory acceptance as a medical product in many jurisdictions has bypassed the traditional evidence-based pathway required for therapies. Easier access to MC, especially related to recreational legalization of cannabis, has led to widespread use by patients for symptom relief of a variety of medical conditions and often without medical oversight. Musculoskeletal pain remains the most common reason for MC use. This review examines real-world issues pertaining to MC and offers some guidance for clinical care of patients with rheumatic diseases being treated with MC.

RECENT FINDINGS

Controlled clinical studies of cannabis products in patients with rheumatic diseases have been small and tested a range of compounds, routes of administration, and clinical populations, limiting our ability to generate conclusions on MC's effectiveness in this population. Observational cohort studies and surveys suggest that use of MC and related products in patients with rheumatic diseases improves pain and associated symptoms but is commonly accompanied by mild to moderate side effects. Conflicting evidence contributes to practitioner and patient uncertainty regarding the use of MC for rheumatic disease-related pain. Despite promising preclinical and observational evidence that MC and cannabis-derived compounds are useful in the management of rheumatic disease-related pain, there remains limited high-quality clinical evidence to substantiate these findings. There are a significant number of clinical trials on this topic currently planned or underway, however, suggesting the next decade may yield more clarity. Nevertheless, given that many people with rheumatic diseases are using cannabis products, healthcare professionals must remain apprised of the evidence pertaining to cannabinoids, communicate such evidence to patients in a meaningful way that is free from personal bias and stigma, and maintain strong collaborative clinical care pertaining to MC.

Edge advances in nanodrug therapies for osteoarthritis treatment

As global population and lifestyles change, osteoarthritis (OA) is becoming a major healthcare challenge world. OA, a chronic condition characterized by inflammatory and degeneration, often present with joint pain and can lead to irreversible disability. While there is currently no cure for OA, it is commonly managed using nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, and glucosamine. Although these treatments can alleviate symptoms, it is difficult to effectively deliver and sustain therapeutic agents within joints. The emergence of nanotechnology, particularly in form of smart nanomedicine, has introduced innovative therapeutic approaches for OA treatment. Nanotherapeutic strategies offer promising advantages, including more precise targeting of affected areas, prolonged therapeutic effects, enhanced bioavailability, and reduced systemic toxicity compared to traditional treatments. While nanoparticles show potential as a viable delivery system for OA therapies based on encouraging lab-based and clinical trials results, there remails a considerable gap between current research and clinical application. This review highlights recent advances in nanotherapy for OA and explore future pathways to refine and optimize OA treatments strategies.

Changes in Pain and Mental Health Symptoms Associated with Prescribed Medicinal Cannabis Use: A One-Year Longitudinal Study

Chronic pain and mental health issues like depression and anxiety significantly contribute to disease burden in Western countries. While cannabinoids are suggested to have analgesic, anxiolytic and antidepressant properties, evidence, especially for long-term use, is inconclusive. This 12-month observational study evaluated the effects of prescribed medicinal cannabis for 96 patients suffering from pain, as well as sleep disturbances, depression and anxiety. Treatment outcomes for pain, depression, anxiety and sleep problems were assessed at 3, 6, and 12 months using validated instruments. Significant reductions were observed in pain scores and the interference of pain on daily functions, alongside improvements in mental health and sleep. Many patients reported notable improvements in pain severity and reduced use of pain medications in the first 6 months, with a decline at 12 months. Additionally, sustained improvements in depression, anxiety, stress and sleep were observed, with about half reporting substantial improvement. Adverse effects were common but mostly mild or moderate, most commonly dry mouth and sleepiness. These results show that prescribed medicinal cannabis treatment is associated with improvements in chronic pain and mental health symptoms, such as depression, anxiety and stress. However, findings also suggest reduced effectiveness with longer-term use, emphasizing the need for additional research.

Cannabis-Based Phytocannabinoids: Overview, Mechanism of Action, Therapeutic Application, Production, and Affecting Environmental Factors

This review provides an overview of cannabis-based phytocannabinoids, focusing on their mechanisms of action, therapeutic applications, and production processes, along with the environmental factors that affect their quality and efficacy. Phytocannabinoids such as THC (∆9-tetrahydrocannabinol), CBD (cannabidiol), CBG (cannabigerol), CBN (cannabinol), and CBC (cannabichromene) exhibit significant therapeutic potential in treating various physical and mental health conditions, including chronic pain, epilepsy, neurodegenerative diseases, skin disorders, and anxiety. The cultivation of cannabis plays a crucial role in determining cannabinoid profiles, with indoor cultivation offering more control and consistency than outdoor methods. Environmental factors such as light, water, temperature, humidity, nutrient management, CO2, and the drying method used are key to optimizing cannabinoid content in inflorescences. This review outlines the need for broader data transfer between the health industry and technological production, especially in terms of what concentration and cannabinoid ratios are effective in treatment. Such data transfer would provide cultivators with information on what environmental parameters should be manipulated to obtain the required final product.

Cannabinoid CB2 receptors enhance high-fat diet evoked peripheral neuroinflammation

It is known that the cannabinoid type 2 (CB2) receptor has an anti-inflammatory role. Therefore, animals without CB2 receptors show enhanced inflammation and pain in the model of chronic pain, e.g., neuropathic pain. We previously proposed the upregulated leptin signaling at the peripheral nerve as one of the underlying molecular mechanisms of pain exacerbation in nerve-injured CB2 knockouts, as they displayed robust upregulation of leptin receptors and leptin signaling in the peripheral nerve. Due to these past results, we hypothesized that CB2 receptor deficiency might also modify the peripheral neuroinflammation led by chronic exposure to a high-fat diet (HFD). Interestingly, CB2 knockout animals showed significant resistance to HFD-induced neuroinflammation. Namely, 5-week feeding of HFD induced substantial hypersensitivity in WT animals, while tactile sensitivity of HFD-fed CB2 knockouts remained intact. HFD-fed WT animals also displayed the robust upregulation of chemokine CXCR4 expression with increased macrophage infiltration, which was never observed in HFD-fed CB2 knockout mice. Moreover, 5-week HFD exposure led significant increase of CD11b+Ly6G-Ly6Chigh cells and a decrease of CD11b+Ly6G+Ly6Clow cells in the spleen of WT animals, which was also not found in either HFD-fed CB2 knockouts or standard diet-fed WT and CB2 animals. Together with past reports, these results suggest that CB2 receptors might have a double-sided regulatory role in the context of inflammation development or, more widely, immune system regulation. We propose that CB2 signaling is not always anti-inflammatory and could take a pro-inflammatory role depending on the cause of the inflammation.

Palmitoylethanolamide as a Supplement: The Importance of Dose-Dependent Effects for Improving Nervous Tissue Health in an In Vitro Model

Palmitoylethanolamide (PEA) is a highly lipophilic molecule with low solubility, making absorption difficult. Recent techniques like micronisation, ultra-micronisation and combining PEA with solvents have improved their bioavailability and stability. Our study analysed particle size differences and absorption kinetics using specific solvents (PEAΩ and PEA DynoΩ) over time (0.5 h-6 h) in a dose-dependent manner (200 mg-1800 mg). The results showed that PEAΩ and PEA DynoΩ achieved 82-63% absorption at 3 h, compared to 30-60% for micronised, ultra-micronised PEA and a commercial product, highlighting the optimal dose range of 300 mg-600 mg. In addition, a 3D model of the peripheral nerve was utilised to explain the efficacy after gut passage and support the most effective dose (300 mg or 600 mg) achieved at the gut level. PEAΩ and PEA DynoΩ, which are associated with better intestinal bioavailability compared to PEA-micronised, PEA ultra-micronised and a commercial product, have allowed not only a reduction in the inflammatory context but also an improvement of peripheral nerve well-being by increasing specific markers like MPZ (26-36% vs. 8-15%), p75 (25-32% vs. 13-16%) and NRG1 (22-29.5% vs. 11-14%). These results highlight the potential of advanced PEA formulations to overcome solubility challenges and maintain in vitro efficacy, modulating peripheral nerve well-being.

The Efficacy of Cannabis in Oncology Patient Care and Its Anti-Tumor Effects

As the legalization of medical cannabis expands across several countries, interest in its potential advantages among cancer patients and caregivers is burgeoning. However, patients seeking to integrate cannabis into their treatment often encounter frustration when their oncologists lack adequate information to offer guidance. This knowledge gap is exacerbated by the scarcity of published literature on the benefits of medical cannabis, leaving oncologists reliant on evidence-based data disheartened. This comprehensive narrative article, tailored for both clinicians and patients, endeavors to bridge these informational voids. It synthesizes cannabis history, pharmacology, and physiology and focuses on addressing various symptoms prevalent in cancer care, including insomnia, nausea and vomiting, appetite issues, pain management, and potential anti-cancer effects. Furthermore, by delving into the potential mechanisms of action and exploring their relevance in cancer treatment, this article aims to shed light on the potential benefits and effects of cannabis in oncology.

The State of Synthetic Cannabinoid Medications for the Treatment of Pain

Synthetic cannabinoids are compounds made in the laboratory to structurally and functionally mimic phytocannabinoids from the Cannabis sativa L. plant, including delta-9-tetrahydrocannabinol (THC). Synthetic cannabinoids (SCs) can signal via the classical endogenous cannabinoid system (ECS) and the greater endocannabidiome network, highlighting their signalling complexity and far-reaching effects. Dronabinol and nabilone, which mimic THC signalling, have been approved by the Food and Drug Administration (FDA) for treating nausea associated with cancer chemotherapy and/or acquired immunodeficiency syndrome (AIDS). However, there is ongoing interest in these two drugs as potential analgesics for a variety of other clinical conditions, including neuropathic pain, spasticity-related pain, and nociplastic pain syndromes including fibromyalgia, osteoarthritis, and postoperative pain, among others. In this review, we highlight the signalling mechanisms of FDA-approved synthetic cannabinoids, discuss key clinical trials that investigate their analgesic potential, and illustrate challenges faced when bringing synthetic cannabinoids to the clinic.

Cannabinoid CB2 receptor orthologues; in vitro function and perspectives for preclinical to clinical translation

Cannabinoid CB2 receptor agonists are in development as therapeutic agents, including for immune modulation and pain relief. Despite promising results in rodent preclinical studies, efficacy in human clinical trials has been marginal to date. Fundamental differences in ligand engagement and signalling responses between the human CB2 receptor and preclinical model species orthologues may contribute to mismatches in functional outcomes. This is a tangible possibility for the CB2 receptor in that there is a relatively large degree of primary amino acid sequence divergence between human and rodent. Here, we summarise CB2 receptor gene and protein structure, assess comparative molecular pharmacology between CB2 receptor orthologues, and review the current status of preclinical to clinical translation for drugs targeted at the CB2 receptor, focusing on comparisons between human, mouse and rat receptors. We hope that raising wider awareness of, and proposing strategies to address, this additional challenge in drug development will assist in ongoing efforts toward successful therapeutic translation of drugs targeted at the CB2 receptor. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.

Cannabidiol and its application in the treatment of oral diseases: therapeutic potentials, routes of administration and prospects

Cannabidiol (CBD), one of the most important active ingredients in cannabis, has been reported to have some pharmacological effects such as antibacterial and analgesic effects, and to have therapeutic potential in the treatment of oral diseases such as oral cancer, gingivitis and periodontal diseases. However, there is a lack of relevant systematic research and reviews. Therefore, based on the etiology and clinical symptoms of several common oral diseases, this paper focuses on the therapeutic potential of CBD in periodontal diseases, pulp diseases, oral mucosal diseases, oral cancer and temporomandibular joint diseases. The pharmacological effects of CBD and the distribution and function of its receptors in the oral cavity are also summarized. In order to provide reference for future research and further clinical application of CBD, we also summarize several possible routes of administration and corresponding characteristics. Finally, the challenges faced while applying CBD clinically and possible solutions are discussed, and we also look to the future.

Identification and Characterization of Cannabichromene's Major Metabolite Following Incubation with Human Liver Microsomes

Cannabichromene (CBC) is a minor cannabinoid within the array of over 120 cannabinoids identified in the Cannabis sativa plant. While CBC does not comprise a significant portion of whole plant material, it is available to the public in a purified and highly concentrated form. As minor cannabinoids become more popular due to their potential therapeutic properties, it becomes crucial to elucidate their metabolism in humans. Therefore, the goal of this was study to identify the major CBC phase I-oxidized metabolite generated in vitro following incubation with human liver microsomes. The novel metabolite structure was identified as 2'-hydroxycannabicitran using gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy. Following the identification, in silico molecular modeling experiments were conducted and predicted 2'-hydroxycannabicitran to fit in the orthosteric site of both the CB1 and CB2 receptors. When tested in vitro utilizing a competitive binding assay, the metabolite did not show significant binding to either the CB1 or CB2 receptors. Further work necessitates the determination of potential activity of CBC and the here-identified phase I metabolite in other non-cannabinoid receptors.

Imaging of Pain using Positron Emission Tomography

Positron emission tomography (PET) is a noninvasive molecular imaging technique that utilizes biologically active radiolabeled compounds to image biochemical processes. As such, PET can provide important pathophysiological information associated with pain of different etiologies. As such, the information obtained using PET often combined with MRI or CT can provide useful information for diagnosing and monitoring changes associated with pain. This review covers the most important PET tracers that have been used to image pain including tracers for fundamental biological processes such as glucose metabolism and cerebral blood flow to receptor-specific tracers such as ion channels and neurotransmitters. For tracer type, we describe the structure and radiochemical synthesis of the tracer followed by a brief summary of the available preclinical and clinical studies. By providing a summary of the PET tracers that have been employed for PET imaging of pain, this review aims to serve as a reference for preclinical, translational and clinical investigators interested in molecular imaging of pain. Finally, the review ends with an outlook of the needs and opportunities in this area.

Cannabidiol Anticonvulsant Effects Against Lithium-Pilocarpine-Induced Status Epilepticus in Male Rats Are Mediated by Neuroinflammation Modulation and Cannabinoids 1 (CB1), But Not CB2 and GABAA Receptors

Background: Status epilepticus (SE) is a series of seizures that can lead to serious neurological damages. Cannabidiol (CBD) is extracted from the cannabis plant, which has been approved as an antiseizure medication. This study aimed to determine the efficacy of various doses of CBD on lithium-pilocarpine-induced SE in rats and possible involvement of multiple pharmacological pathways. We hypothesized that cannabinoid receptors type 1 (CB1) and CB2, as well as GABAA receptors, might have important roles in the anticonvulsant effects of CBD against SE by its anti-inflammatory effects. Methods: SE was induced by intraperitoneal (i.p.) injection of lithium (127 mg/kg, i.p.) and pilocarpine (60 mg/kg, i.p., 20 h after lithium). Forty-two male rats were divided into seven groups (including control and sham groups), and the treated groups received different doses of CBD (1, 3, 5, 10, and 25 mg/kg, i.p.). SE score was recorded over the next 2 h following pilocarpine injection. Then, we measured the levels of pro-inflammatory cytokines, including interleukin (IL)-lβ and tumor necrosis factor (TNF)-α, using ELISA kits. Also we analyzed the expression of CB1, CB2, and GABAA receptors using the Western blot technique. Results: CBD at 5 mg/kg significantly reduced Racine's scale and duration of seizures, and increased the onset time of seizure. Moreover, CBD 5 mg/kg caused significant reductions in the elevated levels of IL-lβ and TNF-α, as well as a significant increase in the decreased level of CB1 receptor expression compared to the control group. In other word, CBD reverted the effects of SE in terms of neuroinflammation and CB1 receptor. Based on the obtained results, CBD was not able to restore the declined levels of CB2 or GABAA receptors. Conclusion: Our study found anticonvulsant effects of CBD on the SE rat model induced by lithium-pilocarpine with probable involvement of CB1 receptors and anti-inflammatory effects by reducing IL-1β and TNF-α markers independent of CB2 and GABAA receptors.

Cannabinoid levels description in a cohort of patients with chronic and neuropathic pain treated with Cannabis decoction: A possible role of TDM

The phytocomplex of Cannabis is made up of approximately 500 substances: terpeno-phenols metabolites, including Δ-9-tetrahydrocannabinol and cannabidiol, exhibit pharmacological activity. Medical Cannabis has several pharmacological potential applications, in particular in the management of chronic and neuropathic pain. In the literature, a few data are available concerning cannabis pharmacokinetics, efficacy and safety. Thus, aim of the present study was the evaluation of cannabinoid pharmacokinetics in a cohort of patients, with chronic and neuropathic pain, treated with inhaled medical cannabis and decoction, as a galenic preparation. In this study, 67 patients were enrolled. Dried flower tops with different THC and CBD concentrations were used: Bedrocan® medical cannabis with THC level standardized at 19% and with a CBD level below 1%, Bediol® medical cannabis with THC and CBD level standardized at similar concentration of 6.5% and 8%, respectively. Cannabis was administered as a decoction in 47 patients and inhaled in 11 patients. The blood withdrawn was obtained before the new dose administration at the steady state and metabolites plasma concentrations were measured with an UHPLC-MS/MS method. Statistically significant differences were found in cannabinoids plasma exposure between inhaled and oral administration of medical cannabis, between male and female and cigarette smokers. For the first time, differences in cannabinoid metabolites exposures between different galenic formulations were suggested in patients. Therapeutic drug monitoring could be useful to allow for dose adjustment, but further studies in larger cohorts of patients are required in order to confirm these data.

The Role of Medicinal Cannabis as an Emerging Therapy for Opioid Use Disorder

This narrative review explores current insights into the potential use of medicinal cannabis-related products as an emerging therapy for opioid use disorder in the landscape of increasing knowledge about medicinal cannabis-based products, commercialisation and global legalisation. Preclinical studies have provided preliminary insight into the putative neurobiological mechanisms that underpin the potential for medicinal cannabis to be considered a therapeutic in opioid use disorder and addiction. With the progressive legalisation of cannabis in many jurisdictions worldwide, contemporary research has highlighted further evidence that medicinal cannabis may have efficacy in reducing cravings and withdrawal effects, and therefore may be considered as an adjunct or standalone to current medications for opioid use disorder. Despite this potential, the landscape of research in this space draws from a large number of observational studies, with a paucity of rigorous randomised controlled trials to ascertain a true understanding of effect size and safety profile. With current challenges in implementation that arise from political and legal qualms about adopting medicinal cannabis on the background of associated social stigma, significant hurdles remain to be addressed by government, policy-makers, healthcare providers and researchers before medical cannabis can be introduced globally for the treatment of opioid use disorder.

How Biodegradable Polymers Can be Effective Drug Delivery Systems for Cannabinoids? Prospectives and Challenges

Cannabinoids are compounds found in and derived from the Cannabis plants that have become increasingly recognised as significant modulating factors of physiological mechanisms and inflammatory reactions of the organism, thus inevitably affecting maintenance of homeostasis. Medical Cannabis popularity has surged since its legal regulation growing around the world. Numerous promising discoveries bring more data on cannabinoids' pharmacological characteristics and therapeutic applications. Given the current surge in interest in the medical use of cannabinoids, there is an urgent need for an effective method of their administration. Surpassing low bioavailability, low water solubility, and instability became an important milestone in the advancement of cannabinoids in pharmaceutical applications. The numerous uses of cannabinoids in clinical practice remain restricted by limited administration alternatives, but there is hope when biodegradable polymers are taken into account. The primary objective of this review is to highlight the wide range of indications for which cannabinoids may be used, as well as the polymeric carriers that enhance their effectiveness. The current review described a wide range of therapeutic applications of cannabinoids, including pain management, neurological and sleep disorders, anxiety, and cancer treatment. The use of these compounds was further examined in the area of dermatology and cosmetology. Finally, with the use of biodegradable polymer-based drug delivery systems (DDSs), it was demonstrated that cannabinoids can be delivered specifically to the intended site while also improving the drug's physicochemical properties, emphasizing their utility. Nevertheless, additional clinical trials on novel cannabinoids' formulations are required, as their full spectrum therapeutical potential is yet to be unravelled.

Phytocannabinoids: Exploring Pharmacological Profiles and Their Impact on Therapeutical Use

Phytocannabinoids, a diverse group of naturally occurring compounds extracted from the Cannabis plant, have attracted interest due to their potential pharmacological effects and medicinal uses. This comprehensive review presents the intricate pharmacological profiles of phytocannabinoids while exploring the diverse impacts these substances have on biological systems. From the more than one hundred cannabinoids which were identified in the Cannabis plant so far, cannabidiol (CBD) and tetrahydrocannabinol (THC) are two of the most extensively studied phytocannabinoids. CBD is a non-psychoactive compound, which exhibits potential anti-inflammatory, neuroprotective, and anxiolytic properties, making it a promising candidate for a wide array of medical conditions. THC, known for its psychoactive effects, possesses analgesic and antiemetic properties, contributing to its therapeutic potential. In addition to THC and CBD, a wide range of additional phytocannabinoids have shown intriguing pharmacological effects, including cannabichromene (CBC), cannabigerol (CBG), and cannabinol (CBN). The endocannabinoid system, made up of the enzymes involved in the production and breakdown of endocannabinoids, cannabinoid receptors (CB1 and CB2), and endogenous ligands (endocannabinoids), is essential for preserving homeostasis in several physiological processes. Beyond their effects on the endocannabinoid system, phytocannabinoids are studied for their ability to modify ion channels, neurotransmitter receptors, and anti-oxidative pathways. The complex interaction between phytocannabinoids and biological systems offers hope for novel treatment approaches and lays the groundwork for further developments in the field of cannabinoid-based medicine. This review summarizes the state of the field, points out information gaps, and emphasizes the need for more studies to fully realize the therapeutic potential of phytocannabinoids.

Elevated risk of prosthetic infections in cannabis users after shoulder arthroplasty

INTRODUCTION

An increasing number of states are beginning to legalize recreational cannabis use, and as such, more patients using cannabis are undergoing shoulder arthroplasty procedures. The present study sought to examine the impact of cannabis use on post-operative outcomes. The primary outcomes of interest were postoperative complications, which included infection, periprosthetic fractures, periprosthetic joint infections (PJI), dislocations, and aseptic loosening as well as medical complications. Secondary outcomes were risk factors for PJI and aseptic loosening at two-years.

METHODS

A private, nationwide, all-payer database (Pearldiver Technologies) was queried to identify shoulder arthroplasty patients from 2010 to 2020. Those not using tobacco or cannabis ("control", n = 10,000), tobacco users (n = 10,000), cannabis users (n = 155), and concurrent tobacco and cannabis users (n = 9,842) were identified. Risk factors for PJI and aseptic loosening at two-years were further quantified utilizing multivariable logistic regression analysis.

RESULTS

Compared to non-users, cannabis users experienced the highest odds for PJI and aseptic revisions, which were followed by concurrent cannabis and tobacco users and tobacco-only users. Concurrent users, as well as tobacco users were at higher risk for dislocation. Cannabis use was the most significant risk factor for PJI, followed by concurrent use and male sex.

CONCLUSIONS

Our study found cannabis use to cause greater risk for superficial and deep infection. More research involving randomized trials are needed to fully elucidate the impact of cannabis use on shoulder arthroplasty procedures. Clinically, these findings can appropriately guide surgeons and patients alike regarding expectations prior to undergoing TSA.

Marijuana Use, Vaping, and Preoperative Anesthetic and Surgical Considerations in Clinical Practice

In recent years, marijuana and vaping have acquired widespread popularity, with millions of people using them for a variety of reasons, including recreational purposes. However, these practices have often overlooked the implications on surgery and the preoperative anesthesia considerations. Marijuana can influence a patient's response to anesthesia, alter postoperative pain management, and increase the risk of complications, whereas vaping can have negative effects on the respiratory system and hinder the body's ability to recover after surgery.

Prevalence of cannabis use disorder and perioperative outcomes in adult colectomy patients: A propensity score-matched analysis

BACKGROUND

The decriminalization of cannabis across the United States has led to an increased number of patients reporting cannabis use prior to surgery. However, it is unknown whether preoperative cannabis use disorder (CUD) increases the risk of postoperative complications among adult colectomy patients.

METHODS

Adult patients undergoing an elective colectomy were retrospectively analyzed from the National Inpatient Sample database (2004-2018). To control for potential confounders, patients with CUD, defined using ICD-9/10 codes, were propensity score matched to patients without CUD in a 1:1 ratio. The association between preoperative CUD and composite morbidity, the primary outcome of interest, was assessed. Subgroup analyses were performed after stratification by age (≥50 years).

RESULTS

Among 432,018 adult colectomy patients, 816 (0.19%) reported preoperative CUD. The prevalence of CUD increased nearly three-fold during the study period from 0.8/1000 patients in 2004 to 2.0/1000 patients in 2018 (P-trend<0.001). After propensity score matching, patients with CUD exhibited similar rates of composite morbidity (140 of 816; 17.2%) as those without CUD (151 of 816; 18.5%) (p = 0.477). Patients with CUD also had similar anastomotic leak rates (CUD: 5.64% vs. No CUD: 6.25%; p = 0.601), hospital lengths of stay (CUD: 5 days, IQR 4-7 vs. No CUD: 5 days, IQR 4-7) (p = 0.415), and hospital charges as those without CUD. Similar findings were seen among patients aged ≥50 years in the subgroup analysis.

CONCLUSIONS

Though the prevalence of CUD has increased drastically over the past 15 years, preoperative CUD was not associated with an increased risk of composite morbidity among adult patients undergoing an elective colectomy.

Tetrahydrocannabinol and Cannabidiol for Pain Treatment-An Update on the Evidence

In light of the current International Association for the Study of Pain (IASP) clinical practice guidelines (CPGs) and the European Society for Medical Oncology (ESMO) guidelines, the topic of cannabinoids in relation to pain remains controversial, with insufficient research presently available. Cannabinoids are an attractive pain management option due to their synergistic effects when administered with opioids, thereby also limiting the extent of respiratory depression. On their own, however, cannabinoids have been shown to have the potential to relieve specific subtypes of chronic pain in adults, although controversies remain. Among these subtypes are neuropathic, musculoskeletal, cancer, and geriatric pain. Another interesting feature is their effectiveness in chemotherapy-induced peripheral neuropathy (CIPN). Analgesic benefits are hypothesized to extend to HIV-associated neuropathic pain, as well as to lower back pain in the elderly. The aim of this article is to provide an up-to-date review of the existing preclinical as well as clinical studies, along with relevant systematic reviews addressing the roles of various types of cannabinoids in neuropathic pain settings. The impact of cannabinoids in chronic cancer pain and in non-cancer conditions, such as multiple sclerosis and headaches, are all discussed, as well as novel techniques of administration and relevant mechanisms of action.

Applications of Cannabinoids in Neuropathic Pain: An Updated Review

Neuropathic pain is experienced due to injury to the nerves, underlying disease conditions or toxicity induced by chemotherapeutics. Multiple factors can contribute to neuropathic pain such as central nervous system (CNS)-related autoimmune and metabolic disorders, nerve injury, multiple sclerosis and diabetes. Hence, development of pharmacological interventions to reduce the drawbacks of existing chemotherapeutics and counter neuropathic pain is an urgent unmet clinical need. Cannabinoid treatment has been reported to be beneficial for several disease conditions including neuropathic pain. Cannabinoids act by inhibiting the release of neurotransmitters from presynaptic nerve endings, modulating the excitation of postsynaptic neurons, activating descending inhibitory pain pathways, reducing neural inflammation and oxidative stress and also correcting autophagy defects. This review provides insights on the various preclinical and clinical therapeutic applications of cannabidiol (CBD), cannabigerol (CBG), and cannabinol (CBN) in various diseases and the ongoing clinical trials for the treatment of chronic and acute pain with cannabinoids. Pharmacological and genetic experimental strategies have well demonstrated the potential neuroprotective effects of cannabinoids and also elaborated their mechanism of action for the therapy of neuropathic pain.

Pharmacokinetics and pharmacodynamics of cannabis-based medicine in a patient population included in a randomized, placebo-controlled, clinical trial

Information on the pharmacokinetics (PK) and pharmacodynamics (PD) of orally administered cannabis-based medicine (CBM) in capsule formulation in patient populations is sparse. In this exploratory study, we aimed to evaluate the PK and PD in a probable steady state of CBM in neuropathic pain and spasticity in a population of patients with multiple sclerosis (MS). Of 134 patients participating in a randomized, double-blinded, placebo-controlled, trial, 23 patients with MS (17 female) mean age 52 years (range 21-67) were enrolled in this substudy. They received oral capsules containing Δ9 -tetrahydrocannabinol (THC, n = 4), cannabidiol (CBD, n = 6), a combination (THC&CBD, n = 4), or placebo (n = 9). Maximum doses were 22.5 mg (THC) and 45 mg (CBD) a day divided into three administrations. PD parameters were evaluated for pain and spasticity. Blood samples were analyzed using an ultra-high-performance liquid chromatography-tandem mass spectrometer after protein precipitation and phospholipid removal. PK parameters were estimated using computerized modeling. The variation in daily dose and PK between individuals was considerable in a steady state, yet comparable with previous reports from healthy controls. Based on a simulation of the best model, the estimated PK parameters (mean) for THC (5 mg) were Cmax 1.21 ng/mL, Tmax 2.68 h, and half-life 2.75 h, and for CBD (10 mg) were Cmax 2.67 ng/mL, Tmax 0.10 h, and half-life 4.95 h, respectively. No effect was found on the PD parameters, but the placebo response was considerable. More immediate adverse events were registered in the active treatment groups compared with the placebo group.

Optimization of Trimming Techniques for Enhancing Cannabinoid and Terpene Content in Medical Cannabis Inflorescences

Introduction

Cannabis sativa L. inflorescences are widely used in the medicinal field as treatments for a variety of symptoms and illnesses due to their unique phytochemicals such as cannabinoids and terpenes. Common postharvest procedures for cannabis inflorescence include trimming, followed by drying, curing, and subsequent storage. The postharvest trimming step, particularly its timing (pre- or post-drying) and the extent of trimming, is not optimally refined in terms of its impact on the cannabinoid and terpene content. In this study, our objective was to identify the optimal trimming conditions for a commercially available medicinal cannabis hybrid chemovar, with the goal of maximizing its cannabinoid and terpene content.

Methods

To achieve this, we investigated the effects of pre- versus post-drying trimming and evaluated the impact of mild versus aggressive trimming prior to drying on the cannabinoid and terpene profiles using liquid and gas chromatography.

Results

Our results indicated that pre-drying mild trimming yielded the highest cannabinoid concentration, possibly due to optimal balance between stress signals and precursor influx from the sugar leaves to the inflorescence. On the other, post-drying trimming yielded the highest terpene content.

Conclusion

Identifying the optimal trimming conditions that maximize both cannabinoid and terpene levels in cannabis is challenging. Therefore, growers face a decision in their trimming practices: to prioritize either enhanced cannabinoid content or increased aromatic terpene concentrations, as optimizing for both simultaneously appears to be difficult.

Medical Cannabis Prescription Practices and Quality of Life in Thai Patients: A Nationwide Prospective Observational Cohort Study

Introduction

The legalization of cannabis in Thailand has renewed interest in its traditional medical use. This study aimed to explore the prescribing patterns of traditional practitioners and assess the impact of cannabis oil on patients' quality of life, with a specific focus on comparing outcomes between cancer and non-cancer patients.

Methods

We conducted a prospective observational cohort study across 30 sites in 21 Thai provinces to analyze the use of "Ganja Oil," a cannabis extract in 10% coconut oil, prescribed for symptoms like pain, anorexia, and insomnia across a diverse patient group, including cancer and migraines. Quality of life was assessed using the Edmonton Symptom Assessment Scale (ESAS) and EQ-5D-5L at baseline, 1, 2, and 3 months. The study included a predefined subgroup analysis to compare the effects on cancer versus non-cancer patients. Data management was facilitated through Research Electronic Data Capture (REDCap), with statistical analysis performed using Stata/MP.

Results

Among 21,284 participants, the mean age was 54.10 ± 15.32 years, with 52.49% being male. The baseline EQ-5D-5L index was 0.85 ± 0.24. Significant differences in EQ-5D-5L indices were seen between cancer patients (0.79 ± 0.32) and non-cancer patients (0.85 ± 0.23; p < 0.001). ESAS scores also differed significantly between these groups for all symptoms, except anxiety. The most frequent prescription of Ganja Oil was oral administration at bedtime (88.26%), with the predominant dosage being three drops daily, approximately 0.204 mg of tetrahydrocannabinol in total. Posttreatment, significant improvements were noted: the EQ-5D-5L index increased by 0.11 points (95% CI: 0.11, 0.11; p < 0.001) overall, 0.13 points (95% CI: 0.12, 0.14; p < 0.001) for cancer patients, and 0.11 points (95% CI: 0.10, 0.11; p < 0.001) for non-cancer patients. ESAS pain scores improved by -2.66 points (95% CI: -2.71, -2.61; p < 0.001) overall, -2.01 points (95% CI: -2.16, -1.87; p < 0.001) for cancer patients, and -2.75 points (95% CI: -2.80, -2.70; p < 0.001) for non-cancer patients, with similar significant improvements in other symptoms.

Conclusion

Our study indicates potential benefits of Ganja Oil for improving quality of life among Thai patients, as a complementary treatment. These findings must be viewed in light of the study's design limitations. Further controlled studies are essential to ascertain its efficacy and inform dosing guidelines.

Neurophysiology of corneal neuropathic pain and emerging pharmacotherapeutics

The altered activity generated by corneal neuronal injury can result in morphological and physiological changes in the architecture of synaptic connections in the nervous system. These changes can alter the sensitivity of neurons (both second-order and higher-order projection) projecting pain signals. A complex process involving different cell types, molecules, nerves, dendritic cells, neurokines, neuropeptides, and axon guidance molecules causes a high level of sensory rearrangement, which is germane to all the phases in the pathomechanism of corneal neuropathic pain. Immune cells migrating to the region of nerve injury assist in pain generation by secreting neurokines that ensure nerve depolarization. Furthermore, excitability in the central pain pathway is perpetuated by local activation of microglia in the trigeminal ganglion and alterations of the descending inhibitory modulation for corneal pain arriving from central nervous system. Corneal neuropathic pain may be facilitated by dysfunctional structures in the central somatosensory nervous system due to a lesion, altered synaptogenesis, or genetic abnormality. Understanding these important pathways will provide novel therapeutic insight.

Cannabis and Cannabinoids in the Perioperative Period

Cannabis use is increasingly common, and with a growing number of jurisdictions implementing legalization frameworks, it is likely that providers will encounter more patients who use cannabis. Therefore, it is important for providers to understand the implications of cannabis use and practical considerations for the perioperative period. Cannabis affects multiple organ systems and may influence intraoperative anesthesia, as well as postoperative pain management. The effects of cannabis and key anesthetic considerations are reviewed here.

Cannabinoids in anesthesia and chronic pain: Where do we stand?

Cannabis derivatives have been conventionally employed globally for their curative and restorative properties for various ailments. However, its recreational use and consequent legal restrictions have substantially cramped its scientific research. An emerging interest regarding the profound therapeutic potential of cannabinoids has been observed among clinicians. Despite a rich cultural background, high-quality research on cannabinoids is lacking in the Indian scenario. This review readdresses the challenges on this front and brings an insight into the current status of cannabinoids and their utility in scientific exploration. Cannabinoids have a significant medicinal value in various clinical disorders. Its use so far has been based on scarce resources and corroborations, as evidence-based substantiation is limited. Through this review article, we emphasize the remarkable role enacted by cannabinoids in the treatment of various clinical disorders and an utterly significant need to formulate stringent research methodologies to promote its systematic investigation.

Cannabinoids, Endocannabinoids, and Synthetic Cannabimimetic Molecules in Neuromuscular Disorders

Neuromuscular disorders (NMDs) encompass a large heterogeneous group of hereditary and acquired diseases primarily affecting motor neurons, peripheral nerves, and the skeletal muscle system. The symptoms of NMDs may vary depending on the specific condition, but some of the most common ones include muscle weakness, pain, paresthesias, and hyporeflexia, as well as difficulties with swallowing and breathing. NMDs are currently untreatable. Therapeutic options include symptomatic and experimental medications aimed at delaying and alleviating symptoms, in some cases supplemented by surgical and physical interventions. To address this unmet medical need, ongoing research is being conducted on new treatments, including studies on medical cannabis, endocannabinoids, and related molecules with cannabimimetic properties. In this context, a significant amount of knowledge about the safety and effectiveness of cannabinoids in NMDs has been obtained from studies involving patients with multiple sclerosis experiencing pain and spasticity. In recent decades, numerous other preclinical and clinical studies have been conducted to determine the potential benefits of cannabinoids in NMDs. This review article aims to summarize and provide an unbiased point of view on the current knowledge about the use of cannabinoids, endocannabinoids, and synthetic analogs in NMDs, drawing from an array of compelling studies.

Anti-allodynic and medullary modulatory effects of a single dose of delta-9-tetrahydrocannabinol (THC) in neuropathic rats tolerant to morphine

Neuropathic pain (NP) is often treated with opioids, the prolonged use of which causes tolerance to their analgesic effect and can potentially cause death by overdose. The phytocannabinoid delta-9-tetrahydrocannabinol (THC) may be an effective alternative analgesic to treat NP in morphine-tolerant subjects. Male Wistar rats developed NP after spared nerve injury, and were then treated with increasing doses of THC (1, 1.5, 2, 2.5, and 5 mg/kg, intraperitoneally), which reduced mechanical allodynia at the dose of 2.5 and 5 mg/kg. Another group of NP rats were treated with morphine (5 mg/kg, twice daily for 7 days, subcutaneously), until tolerance developed, and on day 8 received a single dose of THC (2.5 mg/kg), which significantly reduced mechanical allodynia. To evaluate the modulation of THC in the descending pain pathway, in vivo electrophysiological recordings of pronociceptive ON cells and antinociceptive OFF cells in the rostroventral medulla (RVM) were recorded after intra-PAG microinjection of THC (10 μg/μl). NP rats with morphine tolerance, compared to the control one, showed a tonic reduction of the spontaneous firing rate of ON cells by 44%, but the THC was able to further decrease it (a hallmark of many analgesic drugs acting at supraspinal level). On the other hand, the firing rate, of the antinociceptive OFF cells was increased after morphine tolerance by 133%, but the THC failed to further activate it. Altogether, these findings indicate that a single dose of THC produces antiallodynic effect in individuals with NP who are tolerant to morphine, acting mostly on the ON cells of the descending pain pathways, but not on OFF cells.

Metallothionein Family Proteins as Regulators of Zinc Ions Synergistically Enhance the Anticancer Effect of Cannabidiol in Human Colorectal Cancer Cells

Cannabidiol (CBD) is a chemical obtained from Cannabis sativa; it has therapeutic effects on anxiety and cognition and anti-inflammatory properties. Although pharmacological applications of CBD in many types of tumors have recently been reported, the mechanism of action of CBD is not yet fully understood. In this study, we perform an mRNA-seq analysis to identify the target genes of CBD after determining the cytotoxic concentrations of CBD using an MTT assay. CBD treatment regulated the expression of genes related to DNA repair and cell division, with metallothionein (MT) family genes being identified as having highly increased expression levels induced by CBD. It was also found that the expression levels of MT family genes were decreased in colorectal cancer tissues compared to those in normal tissues, indicating that the downregulation of MT family genes might be highly associated with colorectal tumor progression. A qPCR experiment revealed that the expression levels of MT family genes were increased by CBD. Moreover, MT family genes were regulated by CBD or crude extract but not by other cannabinoids, suggesting that the expression of MT family genes was specifically induced by CBD. A synergistic effect between CBD and MT gene transfection or zinc ion treatment was found. In conclusion, MT family genes as novel target genes could synergistically increase the anticancer activity of CBD by regulating the zinc ions in human colorectal cancer cells.

Expression of Cannabinoid Receptors in the Trigeminal Ganglion of the Horse

Cannabinoid receptors are expressed in human and animal trigeminal sensory neurons; however, the expression in the equine trigeminal ganglion is unknown. Ten trigeminal ganglia from five horses were collected post-mortem from an abattoir. The expression of cannabinoid receptors type 1 (CB1R) and type 2 (CB2R), and the cannabinoid-related receptors like transient receptor potential vanilloid type 1 (TRPV1), peroxisome proliferator-activated receptor gamma (PPARɣ), and G protein-related receptor 55 (GPR55) in the trigeminal ganglia (TG) of the horse were studied, using immunofluorescence on cryosections and formalin-fixed paraffin-embedded (FFPE) sections. Neurons and glial cells were identified using fluorescent Nissl staining NeuroTrace® and an antibody directed against the glial marker glial fibrillary acidic protein (GFAP), respectively. Macrophages were identified by means of an antibody directed against the macrophages/microglia marker ionized calcium-binding adapter molecule 1 (IBA1). The protein expression of CB1R, CB2R, TRPV1, and PPARɣ was found in the majority of TG neurons in both cryosections and FFPE sections. The expression of GPR55 immunoreactivity was mainly detectable in FFPE sections, with expression in the majority of sensory neurons. Some receptors were also observed in glial cells (CB2R, TRPV1, PPARγ, and GPR55) and inflammatory cells (PPARγ and GPR55). These results support further investigation of such receptors in disorders of equine trigeminal neuronal excitability.

Cannabis Use in Patients With Distal Radius Fractures: A Moment of Unity?

BACKGROUND

As legalization of cannabis spreads, an increasing number of patients who use cannabis are being seen in the clinical setting. This study examined the impact of cannabis and tobacco use on postoperative complications following open reduction and internal fixation (ORIF) of distal radius fractures.

METHODS

A national, all-payer database was queried to identify patients who underwent ORIF of a distal radius fracture between 2015 and 2020 (n = 970 747). Patients were stratified into the following groups: (1) tobacco use (n = 86 941), (2) cannabis use (n = 898), (3) tobacco and cannabis use (n = 9842), and (4) neither tobacco nor cannabis use ("control", 747 892). Multivariable logistic regression was used to identify risk factors for infection, nonunion, and malunion within the first postoperative year.

RESULTS

Concomitant use of tobacco and cannabis was associated with a higher rate of nonunion (5.0%) compared to tobacco or cannabis use alone (P < .001). Multivariate analysis identified cannabis-only use (odds ratio [OR] 1.25), tobacco-only use (OR 2.17), and concurrent tobacco and cannabis use (OR 1.78) as risk factors for infection within the first postoperative year. Similarly, cannabis-only use (OR 1.47), tobacco-only use (OR 1.92), and concurrent tobacco and cannabis use (OR 2.52) were associated with an increased risk of malunion.

CONCLUSIONS

Cannabis use is associated with an elevated risk of infection and malunion following operative management of a distal radius fracture. Concomitant use of cannabis and tobacco poses an elevated risk of nonunion and malunion compared to tobacco use alone.

A type II cannabis extract and a 1:1 blend of Δ(9)-tetrahydrocannabinol and cannabidiol display distinct antinociceptive profiles and engage different endocannabinoid targets when administered into the subarachnoid space

Introduction: Cannabis extracts are being increasingly used to mitigate chronic pain. Current guidelines for their prescription rely on Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) content as well as the ratio of these major cannabinoids present in the blend. Here we assessed whether these descriptors were representative of product effectiveness to produce a desired outcome such as analgesia. Methods: In this study, we used a rat model of diabetic neuropathy and assessed the reduction in mechanical allodynia following intrathecal injection of pure THC, pure CBD, a 1:1 mix of these compounds and a "balanced" chemotype II cannabis extract. Engagement of endocannabinoid targets by different treatments was investigated using CB1 (AM251) and CB2 (AM630) receptor antagonists as well as a TRPV1 channel blocker (capsazepine). Results: Antinociceptive responses induced by an equivalent amount of THC administered in its pure form, as a THC:CBD mix or as a "balanced" extract were distinct. Furthermore, the 1:1 THC:CBD mix and the balanced extract had not only different response profiles but their relative engagement of CB1, CB2 receptors and TRPV1 channels was distinct. Discussion: These findings indicate that antinociceptive responses and targets engaged by blended cannabinoids are composition-specific, and cannot be simply inferred from THC and CBD contents. This information may have implications in relation to the way medicinal cannabis products are prescribed.

Unveiling the angiogenic effects of cannabinoids: Enhancers or inhibitors?

Cannabinoids are compounds found in the cannabis sativa plant. Cannabinoids, such as delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), have potential therapeutic benefits in various medical conditions. Some can activate the cannabinoid receptors type-1 and -2 (CB1 and CB2), that are part of the endocannabinoid system (ECS), alongside the endocannabinoids and their metabolic enzymes. The ECS regulates physiological and cognitive processes and is a potential therapeutic target for a wide range of health conditions like chronic pain, anxiety, and neurodegenerative diseases. Synthetic cannabinoids, are associated with serious health risks, including addiction, psychosis, and death. Nonetheless, some of these molecules are also being explored for pharmacological applications. Angiogenesis is the process of forming new blood vessels from existing ones, crucial for growth, repair, and tissue maintenance. Dysregulation of this process is associated with several diseases, including cancer, diabetic retinopathy and reproductive pathologies, such as preeclampsia. Recent data suggests that cannabinoids may affect angiogenesis. Here, we reviewed their impact on pro-angiogenic factors, extracellular matrix enzymes and inhibitors, immune-inflammatory responses, angiogenic pathways and functional assays, focusing on the main compounds for each cannabinoid class: THC and CBD for phytocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG) for endocannabinoids and WIN-55, JWH-133, XLR-11, LYR-7 and LYR-8, for the synthetic cannabinoids. Despite conflicting reports about the actions of phytocannabinoids and endocannabinoids on angiogenesis, the ability to modulate the angiogenic process is undoubtedly confirmed. This may open a new therapeutical route for angiogenesis-related pathologies. In addition, synthetic cannabinoids present anti-angiogenic actions in several cell models, hinting their potential as anti-angiogenic drugs.

Cannabicitran: Its unexpected racemic nature and potential origins

Cannabicitran is a cannabinoid found in levels up to ~10% in commercial "purified" cannabidiol (CBD) extracts. The structure of this natural product was first reported more than 50 years ago. However, few studies have investigated cannabicitran or its origin despite the rapidly increasing interest in the use of cannabinoids for the treatment of a wide range of physiological conditions. Following on a recent detailed NMR and computational characterization of cannabicitran, our group initiated ECD and TDDFT studies aimed at unequivocally determining the absolute configuration of cannabicitran present in Cannabis sativa extracts. To our surprise, we discovered the natural product was racemic, raising questions around its presumed enzymatic origin. Herein, we report the isolation and absolute configuration of (-)-cannabicitran and (+)-cannabicitran. Several possible scenarios for production of the racemate in the plant and/or during extract processing are discussed.

Nutraceuticals for Fibromyalgia and Neuropathic Pain

Both neuropathic pain and fibromyalgia are horrific painful conditions arising due to impairment in the somatosensory nervous system and the musculoskeletal system, respectively. They share some common symptoms like hyperalgesia, allodynia, insomnia, cognitive deficits, and mood disturbances. It is believed that fibromyalgia is the consequence of dysfunction of the central nervous system, autonomic nervous system, imbalance in neurotransmitters, and psychological and emotional stress. Henceforth, these pain syndromes have become a major challenge for healthcare professionals due to their complex etiology and poor availability and effectiveness of the drugs. Notably, the available synthetic drugs possess serious side effects including physical dependence and tolerance. Therefore, researchers are now seeking natural-based therapy for modulating chronic pain conditions. This chapter has been written with the intention of exploring the beneficial effects of various nutraceuticals including herbal dietary supplements in neuropathic pain and fibromyalgia.

The role of cannabinoid CB1 receptors in the antinociceptive and reparative actions of mesenchymal stem cells in rats with peripheral neuropathic pain

Mesenchymal stem cells (MSCs) can produce antinociceptive and reparative effects. Presumably, the MSCs-induced antinociception may be partly due to the involvement of the endocannabinoid system. The study aimed to evaluate the antinociceptive and reparative effects of adipose-derived MSCs (ADMSCs) upon pharmacological modulation of cannabinoid CB1 receptor in peripheral tissues or on ADMSCs' membranes in a rat model of peripheral neuropathy. ADMSCs were injected into the area of rat sciatic nerve injury (i) with no additional treatments, (ii) at the tissue CB1 receptor activation by endogenous agonist anandamide (AEA) or blockade with a selective AM251 antagonist; and (iii) preincubated with AEA or AM251. The evaluation of CB1 receptor activity involved analyzing nociceptive responses, gait parameters, and histology. Transplantation of ADMSCs upon activation of CB1 receptors, both on AMSCs' membranes or in the area of nerve injury, accelerated the analgesia and recovery of dynamic gait parameters, abolished static gait disturbances, and promoted the fastest nerve regeneration. Only blockade of CB1 receptors on ADMSCs shortened ADMSCs-induced analgesia and decreased the number of preserved nerve fibers. CB1 receptors on ADMSCs significantly contribute to their pain-relieving and tissue-repairing capabilities by stimulating the growth factors secretion and suppressing the release of pro-inflammatory cytokines. Peripheral CB1 receptors do not significantly influence ADMSC-induced antinociception.

Diastereoselective and Scalable Synthesis of 6-(S)-Hydroxycannabidivarin

The synthesis of 6-(S)-hydroxycannabidivarin was required to assess its biological activity in the treatment of neurological disorders. A novel and scalable synthesis has been developed where the key step involves a Friedel-Crafts alkylation of phloroglucinol with (1S,2R,5R)-2-hydroxy-2-methyl-5-(prop-1-en-2-yl)cyclohex-3-en-1-ylbenzoate. Careful optimization of the reaction conditions identified trifluoromethanesulfonic acid in isopropyl acetate as the best catalyst/solvent combination, providing optimum regioselectivity, diastereoselectivity, and yield for this step. This enabled the multigram synthesis of 6-(S)-hydroxycannabidivarin in 10 steps from S-(+)-carvone.

Prevalence of cannabidiol (CBD) consumption and cancer patients' expectations in one oncology day-hospital: A cross-sectional study and questionnaire validation

INTRODUCTION

The growing interest of cannabidiol (CBD) in medical care prompted French health authorities to explore the potential of CBD in cancer-related severe symptoms. This study aimed to assess the prevalence of CBD use among cancer patients with potential associated factors and to measure the cancer patient's health literacy (HL) on CBD consumption.

METHODS

In a prospective study in oncology day-care hospital including patients from 29 October to 20 December 2021, we collected demographic, biological, and oncological characteristics. Patient CBD HL was measured by the hetero-questionnaire 8-item-CBD HL scale (HLS-8-CBD) whose conception has been validated by a psychometric analysis.

RESULTS

Among 363 participants, 20 patients (5.5%) reported CBD use. Factors associated with CBD use were: age <60 years (odd ratio = 7.80[1.36-13.32], p < 10^-4 versus ≥60 years), smoking history (OR = 5.53[1.81-16.88], p < 0.01), and no smoking cessation (OR = 5.07[1.66-15.46], p < 0.01). CBD use was also associated with a better CBD total HL score than non-users (p-value = 0.02).

CONCLUSION

Identification of factors associated with CBD use and a relatively high patient CBD HL in CBD users showed that CBD use in cancer patients care represented a new concern and should enhance health professionals to consider CBD with its associated drug-related problems.

Determining Antioxidant Activity of Cannabis Leaves Extracts from Different Varieties-Unveiling Nature's Treasure Trove

Cannabis leaves contain a diverse range of antioxidants, including cannabinoids, flavonoids, and phenolic compounds, which offer significant health benefits. Utilising cannabis leaves as a source of antioxidants presents a cost-effective approach because they are typically discarded during the cultivation of cannabis plants for their seeds or fibres. Therefore, this presented study aimed to assess the antioxidant activity of the leaves of selected hemp cultivars, such as Białobrzeska, Tygra, and Henola, based on the results obtained with the 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid, ferric reducing antioxidant power, cupric reducing antioxidant capacity, and 2,2-Diphenyl-1-picrylhydrazyl assays. The cannabinoid profile was analysed for the antioxidant activity to the contents of cannabidiol (CBD), cannabigerol (CBG), Δ⁹-tetrahydrocannabinol (Δ⁹-THC), and cannabichromene (CBC), determined based on chromatographic assays. The following variables were tested: the impact of various extractants (methanol, ethanol, and isopropanol), and their mixtures (50:50, v/v, as well as extraction methods (maceration and ultra-sound-assisted extraction) significant in obtaining hemp extracts characterised by different cannabinoid profiles. The results revealed that the selection of extractant and extraction conditions significantly influenced the active compounds' extraction efficiency and antioxidant activity. Among the tested conditions, ultrasound-assisted extraction using methanol yielded the highest cannabinoid profile: CBD = 184.51 ± 5.61; CBG = 6.10 ± 0.21; Δ9-THC = 0.51 ± 0.01; and CBC = 0.71 ± 0.01 μg/g antioxidant potential in Białobrzeska leaf extracts.