Phytocannabinoids for the Treatment of Neuropathic Pain: A Scoping Review of Randomised Controlled Trials Published Between 2012 and 2023

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“Purpose of review: Neuropathic pain (NP) remains a challenge to treat, with 50% of patients experiencing limited efficacy from current treatments. Medicinal cannabis, which contains tetrahydrocannabinol (THC), cannabidiol (CBD) and other minor cannabinoids, is garnering attention as an alternative treatment for NP. This paper reviews the clinical evidence for phytocannabinoid treatment of NP.

Recent findings: Seventeen randomised controlled trials (RCT) were identified for inclusion in this review. Of these, ten studies using phytocannabinoid preparations containing THC alone had the most evidence for pain relief. Four studies investigating THC/CBD combinations showed some reductions in pain scores, although not all findings were statistically significant, whereas studies investigating CBD (two studies) or cannabidivarin (one study) showed no analgesic effect over placebo. However, CBD studies were of small sample size when compared to other studies in the review and short duration. Results for treatment of diabetic peripheral neuropathy patients with THC showed better improvements over those for NP induced by chemotherapy and multiple sclerosis, with these trials using vaporised whole plant cannabis. This formulation may have trace amounts of other minor cannabinoids, compared with synthetic cannabinoids such as dronabinol or nabilone that were investigated in other studies. This review provides an overview of RCTs that have investigated phytocannabinoid use for the treatment of NP. There appears to be evidence to necessitate further high quality RCTs into novel formulations of phytocannabinoids for the treatment of NP.”

https://pubmed.ncbi.nlm.nih.gov/38095748/

https://link.springer.com/article/10.1007/s11916-023-01196-1

Divergent synthesis of fractionated Cannabis sativa extract led to multiple cannabinoids C-&O-glycosides with anti-proliferative/anti-metastatic properties

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“Here, we present an interesting, previously unreported method for fractionating a particular class of cannabinoids from the crude leaf extract of Cannabis sativa using HP-20 resins. In this study, we report a novel method of divergent synthesis of fractionated Cannabis sativa extract, which allows the generation of multiple cannabinoids C- and O-glycosides which react with the glycosyl donor 2,3,4,6-tetra-O-acetyl-d-mannosyl trichloroacetimidate (TAMTA) to create eight C- and O-β-d-cannabinoids glycosides (COCG), which are separated by HPLC and whose structures are characterized by 1D, 2D NMR, and mass spectrometry.

These glycosides exhibit improved anti-proliferative and anti-metastatic effects against numerous cancer cell lines in vitro and are more water-soluble and stable than their parent cannabinoids. The in vitro testing of the pure cannabinoids (1-4) and their C- & O-glycosides (1a-4a) and 1b-4b exhibited anti-proliferative and anti-metastatic activities against a panel of eight human cancer cell lines in contrast to their respective parent molecules. Different cancer cell lines’ IC50 values varied significantly when their cell viability was compared. In addition to the others, compounds 2a, 3a, 4a, and 2b, 3b were highly potent, with IC50values ranging from 0.74 µM (3a) to 51.40 µM (4a).Although2a(1.42 µM) and3a(0.74 µM) exhibited lower IC50values in the MiaPaca-2 cell line than4a(2.58 µM). But, in addition to the comparable anti-clonogenic activity of4ain MiaPaca-2 and Panc-1 cells, it manifested remarkable anti-invasive activity than either 2a or 3a.In contrast to 2a, 2b, 3a, and 3b and their respective parent compounds,4ahad substantial anti-invasive/anti-metastatic capabilities and possessed anti-proliferative activity.The effects of 4a treatment on MiaPaca-2 and Panc-1 cells include a dose-dependent increase in the expression of E-cadherin and a significant decrease in the expression of Zeb-1, Vimentin, and Snail1.

Our results demonstrate that divergent synthesis of fractionated Cannabis sativa extract is a feasible and efficient strategy to produce a library of novel cannabinoid glycosides with improved pharmacological properties and potential anticancer benefits.”

https://pubmed.ncbi.nlm.nih.gov/38091718/

https://www.sciencedirect.com/science/article/abs/pii/S0045206823006910?via%3Dihub

Medical Cannabis: A Review from the American Society of Pain and Neuroscience

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“Cannabinoids have recently gained a renewed interest due to their potential applicability to various medical conditions, specifically the management of chronic pain conditions.

Unlike many other medications, medical cannabis is not associated with serious adverse events, and no overdose deaths have been reported.

However, both safety and efficacy data for medical cannabis treatment of chronic, nonmalignant pain conditions are lacking. Therefore, representatives from the American Society of Pain and Neuroscience summarize the evidence, according to level and grade, for medical cannabis treatment of several different pain conditions. Treatment of cancer-related pain has prospective evidentiary support for the use of medical cannabis. Although 3 large and well-designed randomized controlled trials investigated cannabis treatment of cancer-related pain, the evidence yielded only a grade D recommendation. Neuropathic pain has been investigated in prospective studies, but a lack of high-quality evidence renders cannabis treatment for this indication a grade C recommendation. Both safety and efficacy data are lacking for use of medical cannabis to treat chronic nonmalignant pain conditions.”

https://pubmed.ncbi.nlm.nih.gov/38094100/

https://www.dovepress.com/medical-cannabis-a-review-from-the-american-society-of-pain-and-neuros-peer-reviewed-fulltext-article-JPR

Cannabis use and atherosclerotic cardiovascular disease: a Mendelian randomization study

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“Background: Association between cannabis use and development of atherosclerotic cardiovascular disease (ASCVD) is inconsistent and challenging to interpret, given existing study limitations.

Methods: Sixty five independent single-nucleotide polymorphisms (SNPs), obtained from a genome-wide association study on lifetime cannabis use, were employed as genetic instruments to estimate the effects of genetically indexed cannabis use on risk of coronary artery disease (CAD) and acute ischemic stroke (IS) using a two-sample Mendelian randomization (MR) approach. Summary statistics on CAD (CARDIoGRAMplusC4D; 60,801 cases and 123,504 controls) and IS (MEGASTROKE; 34,217 cases and 406,111 controls) were obtained separately. A comprehensive review of the observational literature on cannabis use and CAD or IS was also performed and contrasted with MR results.

Results: There was no causal effect of cannabis use on the risk of CAD (odds ratio (OR) per ever-users vs. never-users 0.93; 95% confidence interval (CI), 0.83 to 1.03) or IS (OR 1.05; 95%CI, 0.93 to 1.19). Sensitivity analyses yielded similar results, and no heterogeneity and directional pleiotropy was observed. Our meta-analysis of observational studies showed no significant association between ever use of cannabis with risk of CAD (k = 6 studies; ORpooled = 1.23, 95%CI 0.78 to 1.69), nor with IS (k = 6 studies; ORpooled = 1.22, 95%CI 0.95 to 1.50).

Conclusion: Using a genetic approach approximating a clinical trial does not provide evidence consistent with a causal effect of genetic predisposition to cannabis use on CAD or IS development. Further studies are needed to replicate our findinds, an to investigate more precisely the risk of ASCVD in relation to the quantity, type, route of administration, or the age at exposure to cannabis.”

https://pubmed.ncbi.nlm.nih.gov/38093188/

https://bmccardiovascdisord.biomedcentral.com/articles/10.1186/s12872-023-03641-w

Identification of Anti-Neuroinflammatory Bioactive Compounds in Essential Oils and Aqueous Distillation Residues Obtained from Commercial Varieties of Cannabis sativa L

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“Neuroinflammation, which is mainly triggered by microglia, is a key contributor to multiple neurodegenerative diseases.

Natural products, and in particular Cannabis sativa L., due to its richness in phytochemical components, represent ideal candidates to counteract neuroinflammation.

We previously characterized different C. sativa commercial varieties which showed significantly different chemical profiles. On these bases, the aim of this study was to evaluate essential oils and aqueous distillation residues from the inflorescences of three different hemp varieties for their anti-neuroinflammatory activity in BV-2 microglial cells. Cells were pretreated with aqueous residues or essential oils and then activated with LPS. Unlike essential oils, aqueous residues showed negligible effects in terms of anti-inflammatory activity. Among the essential oils, the one obtained from ‘Gorilla Glue’ was the most effective in inhibiting pro-inflammatory mediators and in upregulating anti-inflammatory ones through the modulation of the p38 MAPK/NF-κB pathway. Moreover, the sesquiterpenes (E)-caryophyllene, α-humulene, and caryophyllene oxide were identified as the main contributors to the essential oils’ anti-inflammatory activity. To our knowledge, the anti-neuroinflammatory activity of α-humulene has not been previously described.

In conclusion, our work shows that C. sativa essential oils characterized by high levels of sesquiterpenes can be promising candidates in the prevention/counteraction of neuroinflammation.”

https://pubmed.ncbi.nlm.nih.gov/38068924/

https://www.mdpi.com/1422-0067/24/23/16601

Characterizing cannabis-prevalent terpenes for neuroprotection reveal a role for α and β-pinenes in mitigating amyloid β-evoked neurotoxicity and aggregation in vitro

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Background: Cannabis Sativa L. (C. sativa) can efficiently synthesize of over 200 terpenes, including monoterpenes, sesquiterpenes and triterpenes that may contribute to the known biological activities of phytocannabinoids of relevance for the burgeoning access to medicinal cannabis formulations globally; however, to date have been uncharacterized. We assessed twelve predominant terpenes in C. sativa for neuroprotective and anti-aggregative properties in semi-differentiated PC12 neuronal cell line that is robust and validated as a cell model responsive to amyloid β (Aβ1-42) protein exposure and oxidative stress.

Methods: Cell viability was assessed biochemically using the MTT assay in the presence of myrcene, β-caryophyllene, terpinolene, limonene, linalool, humulene, α-pinene, nerolidol, β-pinene, terpineol, citronellol and friedelin (1-200μM) for 24hr. Sub-toxic threshold test concentrations of each terpene were then applied to cells, alone or with concomitant incubation with the lipid peroxidant tert-butyl hyrdroperoxide (t-BHP; 0-250μM) or amyloid β (Aβ1-42; 0-1μM) to assess neuroprotective effects. Direct effects of each terpene on Aβ fibril formation and aggregation were also evaluated using the Thioflavin T (ThT) fluorometric kinetic assay and transmission electron microscopy (TEM) to visualize fibril and aggregate morphology

Results: Terpenes were intrinsically benign to PC12 cells up to 50μM, with higher concentrations of β-caryophyllene, humulene and nerolidol inducing some loss of PC12 cell viability. No significant protective effects of terpenes were observed following t-BHP (0-200µM) administration, with some enhanced toxicity instead demonstrated from both β-caryophyllene and humulene treatment (each at 50µM). α-pinene and β-pinene demonstrated a significant neuroprotective effect against amyloid β exposure. α-pinene, β-pinene, terpineol, terpinolene and friedelin were associated with a variable inhibition of Aβ1-42 fibril and aggregate density.

Conclusions: The outcomes of this study underline a neuroprotective role of α-pinene and β-pinene against Aβ-mediated neurotoxicity associated with an inhibition of Aβ1-42 fibrilization and density. This demonstrates the bioactive potential of selected terpenes for consideration in the development of medicinal cannabis formulations targeting neurodegenerative diseases.”

https://pubmed.ncbi.nlm.nih.gov/38070653/

“In summary, the outcomes from this study reveal a novel and efficacious neuroprotective and anti-aggregatory effect of α-pinene and β-pinene against β amyloid-mediated toxicity. The modest inhibition of lipid peroxidation from α-pinene, β-pinene, and terpinolene may also contribute to the multifaceted neuroprotection of C. sativa-prevalent terpenes. In addition, limited anti-aggregatory effects were observed from terpineol, terpinolene, α-pinene, β-pinene and friedelin. The outcomes of this study contribute to an emerging body of knowledge towards the potential synergistic bioactivities of selected terpenes for consideration in the development of medicinal cannabis formulations targeting neurodegenerative diseases.”

https://www.sciencedirect.com/science/article/pii/S0161813X23001699?via%3Dihub

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

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“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.”

https://pubmed.ncbi.nlm.nih.gov/38068944/

“In conclusion, CBD requires the expression of MT family genes for its anticancer activity during cancer treatment, suggesting that CBD can affect the expression of genes involved in zinc homeostasis via MT family gene expression. These current results suggest that the regulation of zinc levels could play an important role in allowing CBD to exert enhanced anticancer effects. Although CBD treatment has shown anticancer effects on many types of cancers, its molecular mechanism remains unclear. In this study, we explained the possible interactions of MT genes, metal ions, and CBD for anticancer effects. The results of this study might provide an important clue for uncovering the mechanisms involved in the anticancer effects of CBD, such as through the regulation of intracellular homeostasis of metal ions.”

https://www.mdpi.com/1422-0067/24/23/16621

Assessing Cannabidiol as a Therapeutic Agent for Preventing and Alleviating Alzheimer’s Disease Neurodegeneration

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“Alzheimer’s disease (AD) is a leading neurodegenerative condition causing cognitive and memory decline. With small-molecule drugs targeting Aβ proving ineffective, alternative targets are urgently needed. Neuroinflammation, which is central to AD’s pathology, results in synaptic and neuronal damage, highlighting the importance of addressing inflammation and conserving neuronal integrity. Cannabidiol (CBD), derived from cannabis, is noted for its neuroprotective and anti-inflammatory properties, having shown efficacy in neuropathic pain management for epilepsy. To investigate the therapeutic efficacy of CBD in AD and to elucidate its underlying mechanisms, we aimed to contribute valuable insights for incorporating AD prevention recommendations into future CBD nutritional guidelines. Aβ1-42 was employed for in vivo or in vitro model establishment, CBD treatment was utilized to assess the therapeutic efficacy of CBD, and RNA-seq analysis was conducted to elucidate the underlying therapeutic mechanism. CBD mitigates Aβ-induced cognitive deficits by modulating microglial activity, promoting neurotrophic factor release, and regulating inflammatory genes. The administration of CBD demonstrated a protective effect against Aβ toxicity both in vitro and in vivo, along with an amelioration of cognitive impairment in mice. These findings support the potential inclusion of CBD in future nutritional guidelines for Alzheimer’s disease prevention.”

https://pubmed.ncbi.nlm.nih.gov/38067101/

https://www.mdpi.com/2073-4409/12/23/2672

The Interplay between Cannabinoid Receptors and Microglia in the Pathophysiology of Alzheimer’s Disease

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“Alzheimer’s disease (AD) is characterized by massive neuronal death, brain atrophy, and loss of neurons and synapses, which all lead to a progressive cognitive decline. Neuroinflammation has been recently identified as one of the main causes of AD progression, and microglia cells are considered to have a central role in this process.

Growing evidence suggests that cannabinoids may be used as preventive treatment for AD.

An altered expression of the endocannabinoids (eCBs) and their receptors (CBRs) is reported in several neurodegenerative disorders, including AD. Moreover, the modulation of CBRs demonstrated neuroprotective effects in reducing aggregated protein deposition, suggesting the therapeutic potential of natural and synthetic CBR ligands in the treatment of neurodegenerative proteinopathies. Here, we review the current knowledge regarding the involvement of CBRs in the modulation of microglia activation phenotypes, highlighting the role of neuroinflammation in the pathogenesis of neurodegenerative diseases, like AD. We also provide an overview of recently developed candidate drugs targeting CBRs that may afford a new innovative strategy for the treatment and management of AD.”

https://pubmed.ncbi.nlm.nih.gov/38068253/

https://www.mdpi.com/2077-0383/12/23/7201

Neuroprotection and Beyond: The Central Role of CB1 and CB2 Receptors in Stroke Recovery

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“The endocannabinoid system, with its intricate presence in numerous cells, tissues, and organs, offers a compelling avenue for therapeutic interventions. Central to this system are the cannabinoid receptors 1 and 2 (CB1R and CB2R), whose ubiquity can introduce complexities in targeted treatments due to their wide-ranging physiological influence. Injuries to the central nervous system (CNS), including strokes and traumatic brain injuries, induce localized pro-inflammatory immune responses, termed neuroinflammation. Research has shown that compensatory immunodepression usually follows, and these mechanisms might influence immunity, potentially affecting infection risks in patients. As traditional preventive treatments like antibiotics face challenges, the exploration of immunomodulatory therapies offers a promising alternative. This review delves into the potential neuroprotective roles of the cannabinoid receptors: CB1R’s involvement in mitigating excitotoxicity and CB2R’s dual role in promoting cell survival and anti-inflammatory responses. However, the potential of cannabinoids to reduce neuroinflammation must be weighed against the risk of exacerbating immunodepression. Though the endocannabinoid system promises numerous therapeutic benefits, understanding its multifaceted signaling mechanisms and outcomes remains a challenge.”

https://pubmed.ncbi.nlm.nih.gov/38069049/

https://www.mdpi.com/1422-0067/24/23/16728