The Basic Science of Cannabinoids

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“The cannabis plant has been used for centuries to manage the symptoms of various ailments including pain.

Hundreds of chemical compounds have been identified and isolated from the plant and elicit a variety of physiological responses by binding to specific receptors and interacting with numerous other proteins.

In addition, the body makes its own cannabinoid-like compounds that are integrally involved in modulating normal and pathophysiological processes.

As the legal cannabis landscape continues to evolve within the United States and throughout the world, it is important to understand the rich science behind the effects of the plant and the implications for providers and patients.

This narrative review aims to provide an overview of the basic science of the cannabinoids by describing the discovery and function of the endocannabinoid system, pharmacology of cannabinoids, and areas for future research and therapeutic development as they relate to perioperative and chronic pain medicine.”

https://pubmed.ncbi.nlm.nih.gov/38100799/

https://journals.lww.com/anesthesia-analgesia/fulltext/2024/01000/the_basic_science_of_cannabinoids.6.aspx

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

In Vitro Evidence of Selective Pro-Apoptotic Action of the Pure Cannabidiol and Cannabidiol-Rich Extract

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“Plant cannabinoids, secondary metabolites of species belonging to the Cannabis genus, can mimic the endocannabinoids’ action and exert biological effects. Considering the contribution of the endocannabinoid system in cell cycle and apoptotic regulation, there is an interest in exploring the potential anti-cancer activities of natural and synthetic cannabinoids. Cannabidiol (CBD), an abundant plant cannabinoid, reveals a low affinity to cannabinoid receptors and, contrary to various cannabinoids, lacks psychoactive action. Here, we present the in vitro assessment of the pro-apoptototic potential of CBD-rich extracts of Cannabis sativa L. (eCBD) compared to purified CBD (pCBD). As demonstrated, both eCBD and pCBD decreased the viability of breast cancer cell line MDA-MB-231 and human prostate cancer cell line PC-3 in a concentration-dependent fashion. Endoplasmic reticulum stress-related apoptosis and morphological changes were induced only in low-serum conditions. Moreover, the effects of eCDB and pCDB were also assessed in non-malignant cell lines (MCF-10A and PNT2) with no alterations of viability noted, ultimately suggesting a selective action of CBD in tumor cells. The results suggest the possible involvement of reactive oxygen species in the response mechanism to eCBD and pCBD, but no clear pattern was observed. We also demonstrated significant changes in gene expression involved in apoptosis and cell cycle control upon extract treatment. Altogether, our study shows the potential of eCBD and pCBD as novel pro-apoptototic agents that can be considered promising in future preclinical and clinical testing.”

https://pubmed.ncbi.nlm.nih.gov/38067615/

https://www.mdpi.com/1420-3049/28/23/7887

Cannabis as a Source of Approved Drugs: A New Look at an Old Problem

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“Cannabis plants have been used in medicine since ancient times. They are well known for their anti-diabetic, anti-inflammatory, neuroprotective, anti-cancer, anti-oxidative, anti-microbial, anti-viral, and anti-fungal activities. A growing body of evidence indicates that targeting the endocannabinoid system and various other receptors with cannabinoid compounds holds great promise for addressing multiple medical conditions. There are two distinct avenues in the development of cannabinoid-based drugs. The first involves creating treatments directly based on the components of the cannabis plant. The second involves a singular molecule strategy, in which specific phytocannabinoids or newly discovered cannabinoids with therapeutic promise are pinpointed and synthesized for future pharmaceutical development and validation. Although the therapeutic potential of cannabis is enormous, few cannabis-related approved drugs exist, and this avenue warrants further investigation. With this in mind, we review here the medicinal properties of cannabis, its phytochemicals, approved drugs of natural and synthetic origin, pitfalls on the way to the widespread clinical use of cannabis, and additional applications of cannabis-related products.”

https://pubmed.ncbi.nlm.nih.gov/38067416/

https://www.mdpi.com/1420-3049/28/23/7686

Cancer-Cachexia-Induced Human Skeletal Muscle Myotube Degeneration Is Prevented via Cannabinoid Receptor 2 Agonism In Vitro

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“Cachexia syndrome, leading to reduced skeletal muscle and fat mass, is highly prevalent in cancer patients, resulting in further negative implications for these patients. To date, there is no approved therapy for cachexia syndrome. The objective of this study was to establish an in vitro model of cancer cachexia in mature human skeletal muscle myotubes, with the intention of exploiting the cell model to assess potential cachexia therapeutics, specifically cannabinoid related drugs. Having cultured and differentiated primary human muscle myoblasts to mature myotubes, we successfully established two cancer cachexia models using conditioned media (CM) from human colon adenocarcinoma (SW480) and from non-small-cell lung carcinoma (H1299) cultured cells. The cancer-CM-induced extensive myotube degeneration, demonstrated by a significant reduction in mature myotube diameter, which progressed over the period studied. Myotube degeneration is a characteristic feature of cancer cachexia and was used in this study as an index of cachexia. Expression of cannabinoid 1 and 2 receptors (CB1R and CB2R) was confirmed in the mature human skeletal muscle myotubes. Subsequently, the effect of cannabinoid compounds on this myotube degeneration were assessed.

Tetrahydrocannabinol (THC), a partial CB1R/CB2R agonist, and JWH133, a selective CB2R agonist, proved efficacious in protecting mature human myotubes from the deleterious effects of both (SW480 and H1299) cancer cachexia conditions.

ART27.13, a full, peripherally selective CB1R/CB2R agonist, currently being trialled in cancer cachexia (IRAS ID 278450, REC 20/NE/0198), was also significantly protective against myotube degeneration in both (SW480 and H1299) cancer cachexia conditions. Furthermore, the addition of the CB2R antagonist AM630, but not the CB1R antagonist Rimonabant, abolished the protective effect of ART27.13. In short, we have established a convenient and robust in vitro model of cancer-induced human skeletal muscle cachexia. The data obtained using the model demonstrate the therapeutic potential of ART27.13 in cancer-induced cachexia prevention and provides evidence indicating that this effect is via CB2R, and not CB1R.”

https://pubmed.ncbi.nlm.nih.gov/38004445/

“Several cannabinoid drugs have emerged as potential therapeutics for various conditions.”

https://www.mdpi.com/1424-8247/16/11/1580

Cannabinoids and Their Receptors in Skin Diseases

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“The therapeutic application of cannabinoids has gained traction in recent years. Cannabinoids interact with the human endocannabinoid system in the skin. A large body of research indicates that cannabinoids could hold promise for the treatment of eczema, psoriasis, acne, pruritus, hair disorders, and skin cancer. However, most of the available data are at the preclinical stage. Comprehensive, large-scale, randomized, controlled clinical trials have not yet been fully conducted. In this article, we describe new findings in cannabinoid research and point out promising future research areas.”

https://pubmed.ncbi.nlm.nih.gov/38003712/

“In recent years, some components of cannabis, also known as marijuana, have been studied. Cannabis has been used for various purposes throughout history, including recreational, medicinal, and industrial uses. In recent years, cannabinoid components are emerging as therapeutic alternatives for patients with a variety of illnesses and conditions. In particular, their anti-inflammatory properties have piqued the interest of dermatologists [1]. Given the growing number of pre-clinical and clinical studies exploring the potential of cannabinoids to treat dermatologic conditions, we here summarize reports of cannabinoid use in dermatologic therapy.”

https://www.mdpi.com/1422-0067/24/22/16523

Cannabis and Endometriosis: The Roles of the Gut Microbiota and the Endocannabinoid System

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“Endometriosis, a chronic condition affecting around 10-14% of women, is challenging to manage, due to its complex pathogenesis and limited treatment options. Research has suggested a potential role of the gut microbiota and the endocannabinoid system in the development and progression of endometriosis. This narrative review aims to explore the role of, and any potential interactions between, the endocannabinoid system (ECS) and the gut microbiota in endometriosis. This review found that both the ECS and microbiota influence endometriosis, with the former regulating inflammation and pain perception and the latter influencing immune responses and hormonal balance. There is evidence that a dysregulation of the endocannabinoid system and the gut microbiota influence endometriosis symptoms and progression via changes in CB1 receptor expression and increased circulating levels of endocannabinoids. Microbial imbalances in the gut, such as increases in Prevotella, have been directly correlated to increased bloating, a common endometriosis symptom, while increases in E. coli have supported the bacterial contamination hypothesis as a potential pathway for endometriosis pathogenesis. These microbial imbalances have been correlated with increases in inflammatory markers such as TNF-α and IL-6, both often raised in those with endometriosis. Protective effects of the ECS on the gut were observed by increases in endocannabinoids, including 2-AG, resulting in decreased inflammation and improved gut permeability. Given these findings, both the ECS and the gut microbiota may be targets for therapeutic interventions for endometriosis; however, clinical studies are required to determine effectiveness.”

https://pubmed.ncbi.nlm.nih.gov/38002684/

https://www.mdpi.com/2077-0383/12/22/7071

An Emerging Strategy for Neuroinflammation Treatment: Combined Cannabidiol and Angiotensin Receptor Blockers Treatments Effectively Inhibit Glial Nitric Oxide Release

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“Cannabidiol (CBD), the major non-psychoactive phytocannabinoid found in cannabis, has anti-neuroinflammatory properties.

Despite the increasing use of CBD, little is known about its effect in combination with other substances. Combination therapy has been gaining attention recently, aiming to produce more efficient effects. Angiotensin II activates the angiotensin 1 receptor and regulates neuroinflammation and cognition. Angiotensin receptor 1 blockers (ARBs) were shown to be neuroprotective and prevent cognitive decline. The present study aimed to elucidate the combined role of CBD and ARBs in the modulation of lipopolysaccharide (LPS)-induced glial inflammation. While LPS significantly enhanced nitric oxide synthesis vs. the control, telmisartan and CBD, when administered alone, attenuated this effect by 60% and 36%, respectively. Exposure of LPS-stimulated cells to both compounds resulted in the 95% inhibition of glial nitric oxide release (additive effect). A synergistic inhibitory effect on nitric oxide release was observed when cells were co-treated with losartan (5 μM) and CBD (5 μM) (by 80%) compared to exposure to each compound alone (by 22% and 26%, respectively). Telmisartan and CBD given alone increased TNFα levels by 60% and 40%, respectively. CBD and telmisartan, when given together, attenuated the LPS-induced increase in TNFα levels without statistical significance. LPS-induced IL-17 release was attenuated by CBD with or without telmisartan (by 75%) or telmisartan alone (by 60%). LPS-induced Interferon-γ release was attenuated by 80% when telmisartan was administered in the absence or presence of CBD. Anti-inflammatory effects were recorded when CBD was combined with the known anti-inflammatory agent dimethyl fumarate (DMF)/monomethyl fumarate (MMF). A synergistic inhibitory effect of CBD and MMF on glial release of nitric oxide (by 77%) was observed compared to cells exposed to MMF (by 35%) or CBD (by 12%) alone. Overall, this study highlights the potential of new combinations of CBD (5 μM) with losartan (5 μM) or MMF (1 μM) to synergistically attenuate glial NO synthesis. Additive effects on NO production were observed when telmisartan (5 μM) and CBD (5 μM) were administered together to glial cells.”

https://pubmed.ncbi.nlm.nih.gov/38003444/

https://www.mdpi.com/1422-0067/24/22/16254

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

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“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.”

https://pubmed.ncbi.nlm.nih.gov/37976207/

https://www.liebertpub.com/doi/10.1089/can.2023.0067