Category Archives: Endocannabinoid System

The Endocannabinoid System in Alzheimer’s Disease: A Network Meta-Analysis

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“The findings concerning the association between endocannabinoid system (ECS) and Alzheimer’s disease (AD) exhibited inconsistencies when examining the expression levels of endocannabinoids. This study aimed to provide a comprehensive summary of the studies regarding alterations of the ECS in AD.

Six databases were thoroughly searched for literature to select relevant studies investigating the ECS in AD, including changes in cannabinoid receptors (CB1R and CB2R), endocannabinoids (2-AG and AEA), and their associated enzymes (FAAH and MAGL). Traditional meta-analysis evaluated the expression levels of the ECS in AD, and the results showed no significant differences in ECS components between healthy controls and AD patients. However, subgroup analysis revealed significantly lower expression levels of CB1R in AD than in controls, particularly in studies using western blot (SMD = -0.88, p < 0.01) and in studies testing CB1R of frontal cortex (SMD = -1.09, p < 0.01). For studies using HPLC, the subgroup analysis indicated significantly higher 2-AG levels in AD than in controls (SMD = 0.46, p = 0.02). Network meta-analysis examined the rank of ECS alterations in AD compared to controls, and the findings revealed that 2-AG and MAGL exhibited the largest increase and CB1R showed the largest decrease relative to the control group.

Based on the findings of traditional meta-analysis and network meta-analysis, we proposed that AD patients may present decreased expression levels of CB1R and increased expression levels of 2-AG and its degrading enzyme MAGL.

Our results may contribute to the growing body of research supporting the therapeutic potential of ECS modulation in the management of AD.”

https://pubmed.ncbi.nlm.nih.gov/39245959/

https://onlinelibrary.wiley.com/doi/10.1002/jnr.25380

Microglial morphological/inflammatory phenotypes and endocannabinoid signaling in a preclinical model of periodontitis and depression

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“Background: Depression is a chronic psychiatric disease of multifactorial etiology, and its pathophysiology is not fully understood. Stress and other chronic inflammatory pathologies are shared risk factors for psychiatric diseases, and comorbidities are features of major depression. Epidemiological evidence suggests that periodontitis, as a source of low-grade chronic systemic inflammation, may be associated with depression, but the underlying mechanisms are not well understood.

Methods: Periodontitis (P) was induced in Wistar: Han rats through oral gavage with the pathogenic bacteria Porphyromonas gingivalis and Fusobacterium nucleatum for 12 weeks, followed by 3 weeks of chronic mild stress (CMS) to induce depressive-like behavior. The following four groups were established (n = 12 rats/group): periodontitis and CMS (P + CMS+), periodontitis without CMS, CMS without periodontitis, and control. The morphology and inflammatory phenotype of microglia in the frontal cortex (FC) were studied using immunofluorescence and bioinformatics tools. The endocannabinoid (EC) signaling and proteins related to synaptic plasticity were analyzed in FC samples using biochemical and immunohistochemical techniques.

Results: Ultrastructural and fractal analyses of FC revealed a significant increase in the complexity and heterogeneity of Iba1 + parenchymal microglia in the combined experimental model (P + CMS+) and increased expression of the proinflammatory marker inducible nitric oxide synthase (iNOS), while there were no changes in the expression of cannabinoid receptor 2 (CB2). In the FC protein extracts of the P + CMS + animals, there was a decrease in the levels of the EC metabolic enzymes N-acyl phosphatidylethanolamine-specific phospholipase D (NAPE-PLD), diacylglycerol lipase (DAGL), and monoacylglycerol lipase (MAGL) compared to those in the controls, which extended to protein expression in neurons and in FC extracts of cannabinoid receptor 1 (CB1) and to the intracellular signaling molecules phosphatidylinositol-3-kinase (PI3K), protein kinase B (Akt) and extracellular signal-regulated kinase 1/2 (ERK1/2). The protein levels of brain-derived neurotrophic factor (BDNF) and synaptophysin were also lower in P + CMS + animals than in controls.

Conclusions: The combined effects on microglial morphology and inflammatory phenotype, the EC signaling, and proteins related to synaptic plasticity in P + CMS + animals may represent relevant mechanisms explaining the association between periodontitis and depression. These findings highlight potential therapeutic targets that warrant further investigation.”

https://pubmed.ncbi.nlm.nih.gov/39245706/

https://jneuroinflammation.biomedcentral.com/articles/10.1186/s12974-024-03213-5

Effects of Cannabidiol on Bone Quality in Ovariectomized Rats

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“The incidence of osteoporosis and related fractures increases significantly with age, impacting public health and associated costs. Postmenopausal osteoporosis results from increased bone resorption due to decreased estrogen levels.

The endocannabinoid system, especially cannabidiol (CBD), has shown therapeutic potential in modulating bone formation. This study investigated the effects of administration of CBD in rats after the onset of with ovariectomy-induced osteopenia (OVX).

Forty-eight female Sprague‒Dawley rats were divided into four groups (n = 12): OVX + CBD, SHAM + CBD, OVX + vehicle, and SHAM + vehicle. CBD was administered intraperitoneally for 3 weeks. After euthanasia, the bone quality, mechanical properties, and bone microarchitecture of the femurs and lumbar vertebrae were assessed by microcomputed tomography (micro-CT), bone densitometry, mechanical tests, and histological and immunohistochemical analyses.

CBD treatment improved the bone mineral density (BMD) of the lumbar vertebrae and increased the BV/TV% and Tb.N in the femoral neck. There were also improvements in the mechanical properties, such as the maximum force and stiffness of the femurs and vertebrae. CBD significantly increased the bone matrix in osteopenic femurs and vertebrae, Although did not significantly influence the expression of RANKL and OPG, in ovariectomized animals, there was an increase in osteoblasts and a decrease in osteoclasts.

Determining the optimal timing for CBD use in relation to postovariectomy bone loss remains a crucial issue. Understanding when and how CBD can be most effective in preventing or treating bone loss is essential to emphasize the importance of early diagnosis and treatment of osteoporosis. However, further studies are needed to explore in more detail the efficacy and safety of CBD in the treatment of postmenopausal osteoporosis.”

https://pubmed.ncbi.nlm.nih.gov/39245783/

https://link.springer.com/article/10.1007/s00223-024-01281-6

Mechanistic Insights into the Impact of WIN 55, 212-2, a Synthetic Cannabinoid, on Adhesion Molecules PECAM-1 and VE-cadherin in HeLa Cells: Implications on Cancer Processes

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“The endocannabinoid (eCB) system comprises endogenous ligands, cannabinoid receptors (CBRs) and proteins involved in their regulation; its alteration leads to many diseases including cancer. Thus, becomes a therapeutic target for synthetic cannabinoids aimed to control cancer cell proliferation, migration, adhesion and invasion. However, little is known about adhesion molecules regulation through CBRs activation.

Consequently, the aim of this study was to evaluate the effects of a CB1/CB2 agonist, WIN-55, 212-2 (WIN), on the regulation of adhesion molecules PECAM-1 and VE-cadherin in HeLa cells. CBRs expression was evaluated by immunofluorescence staining in HeLa cells. Cell viability by MTT, cell adhesion by crystal violet, adhesion molecules expression and location by Western blot and immunofluorescence staining assays were assessed on cells treated with different WIN concentrations.

Results show that CB1, CB2 and GPR55 receptors are expressed in HeLa cells. Additionally, biphasic effects were observed in their metabolic activity and adhesive properties: low WIN concentrations significantly increased them, in contrast, were decreased at high ones as compared to controls (p < 0.0001), demonstrating that WIN elicits opposite effects depending on the concentration and exposure time. PECAM-1 was detected in cytoplasm, membrane and perinuclear region of HeLa cells, whereas VE-cadherin had a nuclear distribution. There were not significant differences in PECAM-1 and VE-cadherin expression and location, suggesting that WIN does not modulate these proteins.

These findings support the potential use of WIN due to its anticancer properties without dysregulating adhesion molecules. WIN possible contribution to inhibit cancer progression should be further investigated.”

https://pubmed.ncbi.nlm.nih.gov/39228102/

https://www.tandfonline.com/doi/full/10.1080/15376516.2024.2399132

A Comprehensive Exploration of the Multifaceted Neuroprotective Role of Cannabinoids in Alzheimer’s Disease across a Decade of Research

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“Alzheimer’s disease (AD), a progressive neurodegenerative disorder, manifests through dysregulation of brain function and subsequent loss of bodily control, attributed to β-amyloid plaque deposition and TAU protein hyperphosphorylation and aggregation, leading to neuronal death.

Concurrently, similar cannabinoids to the ones derived from Cannabis sativa are present in the endocannabinoid system, acting through receptors CB1R and CB2R and other related receptors such as Trpv-1 and GPR-55, and are being extensively investigated for AD therapy.

Given the limited efficacy and adverse effects of current available treatments, alternative approaches are crucial. Therefore, this review aims to identify effective natural and synthetic cannabinoids and elucidate their beneficial actions for AD treatment. PubMed and Scopus databases were queried (2014-2024) using keywords such as “Alzheimer’s disease” and “cannabinoids”.

The majority of natural (Δ9-THC, CBD, AEA, etc.) and synthetic (JWH-133, WIN55,212-2, CP55-940, etc.) cannabinoids included showed promise in improving memory, cognition, and behavioral symptoms, potentially via pathways involving antioxidant effects of selective CB1R agonists (such as the BDNF/TrkB/Akt pathway) and immunomodulatory effects of selective CB2R agonists (TLR4/NF-κB p65 pathway).

Combining anticholinesterase properties with a cannabinoid moiety may enhance therapeutic responses, addressing cholinergic deficits of AD brains. Thus, the positive outcomes of the vast majority of studies discussed support further advancing cannabinoids in clinical trials for AD treatment.”

https://pubmed.ncbi.nlm.nih.gov/39201317/

“As understood from the above, cannabinoids exhibit efficacy in reversing several of the manifestations of AD.”

https://www.mdpi.com/1422-0067/25/16/8630

Circulating endocannabinoid levels in SARS-CoV-2 infection and their potential role in the inflammatory response

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“Plasma levels of endocannabinoids (eCBs) are very dynamic and variable in different circumstances and pathologies. The aim of the study was to determine the levels of the main eCBs and N-acylethanolamines (NAEs) in COVID-19 patients during the acute and post-acute phase of SARS-CoV-2 infection. Samples collected before December 31, 2020 were used for the determination of circulating eCB levels by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The association between plasma eCB measurements and biochemical and hematological parameters, as well as serum IL-6 levels, was evaluated. Samples of 64 individuals were analysed, n = 18 healthy donors, n = 30 acute, and n = 16 post-acute patients. Plasma levels of 2-arachidonoylglycerol (2-AG), were significantly elevated in COVID-19 patients when compared to healthy individuals. Plasma N-palmitoylethanolamide (PEA) and N-arachidonoylethanolamide (AEA) levels were found to be decreased in post-acute patient samples. These results suggest that 2-AG plays an important role in the inflammatory cascade in COVID-19 disease; in addition, eCBs might be involved in the post-acute pathogenesis of COVID-19. This study provides evidence of altered levels of circulating eCBs as a consequence of SARS-CoV-2 infection.”

https://pubmed.ncbi.nlm.nih.gov/39174572/

“This study shows that circulating eCBs have been altered following SARS-CoV-2 infection. These variations mainly concern 2-AG that showed increased levels that persisted even 30–60 days post-infection. Further studies are needed to address the potential role of the ECS in the SARS-CoV-2 inflammatory response and its potential role in long COVID development.”

https://www.nature.com/articles/s41598-024-70172-5

Cannabinoids and triple-negative breast cancer treatment

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“Triple-negative breast cancer (TNBC) accounts for about 10-20% of all breast cancer cases and is associated with an unfavorable prognosis. Until recently, treatment options for TNBC were limited to chemotherapy. A new successful systemic treatment is immunotherapy with immune checkpoint inhibitors, but new tumor-specific biomarkers are needed to improve patient outcomes.

Cannabinoids show antitumor activity in most preclinical studies in TNBC models and do not appear to have adverse effects on chemotherapy.

Clinical data are needed to evaluate efficacy and safety in humans. Importantly, the endocannabinoid system is linked to the immune system and immunosuppression. Therefore, cannabinoid receptors could be a potential biomarker for immune checkpoint inhibitor therapy or a novel mechanism to reverse resistance to immunotherapy. In this article, we provide an overview of the currently available information on how cannabinoids may influence standard therapy in TNBC.”

https://pubmed.ncbi.nlm.nih.gov/39176080/

“Selective CB2R agonists and antagonists are needed to develop potential anti-cancer drugs that target the endocannabinoid system,”

https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1386548/full

Bioelectronic sensing platform emulating the human endocannabinoid system for assessing and modulating of cannabinoid activity

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“Cannabinoids are involved in physiological and neuromodulatory processes through their interactions with the human cannabinoid receptor-based endocannabinoid system. Their association with neurodegenerative diseases and brain reward pathways underscores the importance of evaluating and modulating cannabinoid activity for both understanding physiological mechanisms and developing therapeutic drugs. The use of agonists and antagonists could be strategic approaches for modulation.

In this study, we introduce a bioelectronic sensor designed to monitor cannabinoid binding to receptors and assess their agonistic and antagonistic properties. We produced human cannabinoid receptor 1 (hCB1R) via an Escherichia coli expression system and incorporated it into nanodiscs (NDs). These hCB1R-NDs were then immobilized on a single-walled carbon nanotube field-effect transistor (swCNT-FET) to construct a bioelectronic sensing platform. This novel system can sensitively detect the cannabinoid ligand anandamide (AEA) at concentrations as low as 1 fM, demonstrating high selectivity and real-time response. It also successfully identified the hCB1R agonist Δ9-tetrahydrocannabinol and observed that the hCB1R antagonist rimonabant diminished the sensor signal upon AEA binding, indicating the antagonism-based modulation of ligand interaction. Consequently, our bioelectronic sensing platform holds potential for ligand detection and analysis of agonism and antagonism.”

https://pubmed.ncbi.nlm.nih.gov/39173339/

https://www.sciencedirect.com/science/article/abs/pii/S0956566324006924?via%3Dihub

Potential Neuroprotective Effect of the Endocannabinoid System on Parkinson’s Disease

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“Parkinson’s disease (PD) is a neurodegenerative disorder characterized by alterations in motor capacity resulting from a decrease in the neurotransmitter dopamine due to the selective death of dopaminergic neurons of the nigrostriatal pathway. Unfortunately, conventional pharmacological treatments fail to halt disease progression; therefore, new therapeutic strategies are needed, and currently, some are being investigated.

The endocannabinoid system (ECS), highly expressed in the basal ganglia (BG) circuit, undergoes alterations in response to dopaminergic depletion, potentially contributing to motor symptoms and the etiopathogenesis of PD. Substantial evidence supports the neuroprotective role of the ECS through various mechanisms, including anti-inflammatory, antioxidative, and antiapoptotic effects. Therefore, the ECS emerges as a promising target for PD treatment.

This review provides a comprehensive summary of current clinical and preclinical evidence concerning ECS alterations in PD, along with potential pharmacological targets that may exert the protection of dopaminergic neurons.”

https://pubmed.ncbi.nlm.nih.gov/39104613/

“Considering current evidence, the ECS emerges as a promising therapeutic target for managing PD, primarily owing to its neuroprotective effects, prominently mediated through anti-inflammatory mechanisms. This is particularly significant since neuroinflammation stands out as a hallmark of PD, and extensive preclinical studies have consistently demonstrated that modulating this inflammatory process mitigates the progression of dopaminergic neuronal death.”

https://onlinelibrary.wiley.com/doi/10.1155/2024/5519396

Beneficial Consequences of One-Month Oral Treatment with Cannabis Oil on Cardiac Hypertrophy and the Mitochondrial Pool in Spontaneously Hypertensive Rats

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“Introduction: It has been demonstrated the dysregulation of the cardiac endocannabinoid system in cardiovascular diseases. Thus, the modulation of this system through the administration of phytocannabinoids present in medicinal cannabis oil (CO) emerges as a promising therapeutic approach. Furthermore, phytocannabinoids exhibit potent antioxidant properties, making them highly desirable in the treatment of cardiac pathologies, such as hypertension-induced cardiac hypertrophy (CH). 

Objective: To evaluate the effect of CO treatment on hypertrophy and mitochondrial status in spontaneously hypertensive rat (SHR) hearts. 

Methods: Three-month-old male SHR were randomly assigned to CO or olive oil (vehicle) oral treatment for 1 month. We evaluated cardiac mass and histology, mitochondrial dynamics, membrane potential, area and density, myocardial reactive oxygen species (ROS) production, superoxide dismutase (SOD), and citrate synthase (CS) activity and expression. Data are presented as mean ± SEM (n) and compared by t-test, or two-way ANOVA and Bonferroni post hoc test were used as appropriate. p < 0.05 was considered statistically significant. 

Results: CH was reduced by CO treatment, as indicated by the left ventricular weight/tibia length ratio, left ventricular mass index, myocyte cross-sectional area, and left ventricle collagen volume fraction. The ejection fraction was preserved in the CO-treated group despite the persistence of elevated systolic blood pressure and the reduction in CH. Mitochondrial membrane potential was improved and mitochondrial biogenesis, dynamics, area, and density were all increased by treatment. Moreover, the activity and expression of the CS were enhanced by treatment, whereas ROS production was decreased and the antioxidant activity of SOD increased by CO administration. 

Conclusion: Based on the mentioned results, we propose that 1-month oral treatment with CO is effective to reduce hypertrophy, improve the mitochondrial pool and increase the antioxidant capacity in SHR hearts.”

https://pubmed.ncbi.nlm.nih.gov/39137344/

https://www.liebertpub.com/doi/10.1089/can.2024.0066