Role of Gut Microbiota in Cannabinoid-Mediated Suppression of Inflammation

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“Cannabinoids and the endocannabinoid system have been well established to play a crucial role in the regulation of the immune response. Also, emerging data from numerous investigations unravel the imperative role of gut microbiota and their metabolites in the maintenance of immune homeostasis and gut barrier integrity. In this review, we concisely report the immunosuppressive mechanisms triggered by cannabinoids, and how they are closely associated with the alterations in the gut microbiome and metabolome following exposure to endogenous or exogenous cannabinoids. We discuss how cannabinoid-mediated induction of microbial secondary bile acids, short chain fatty acids, and indole metabolites, produced in the gut, can suppress inflammation even in distal organs. While clearly, more clinical studies are necessary to establish the cross talk between exo- or endocannabinoid system with the gut microbiome and the immune system, the current evidence opens a new avenue of cannabinoid-gut-microbiota-based therapeutics to regulate immunological disorders.”

“The microbiome-eCB signaling modulation exploiting exo- or endogenous cannabinoids opens a new avenue of cannabinoid-gut microbiota-based therapeutics to curb metabolic and immune-oriented conditions.”

Impact of Cannabis Use on Inpatient Inflammatory Bowel Disease Outcomes in 2 States Legalizing Recreational Cannabis

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“Background: We evaluated the impact of recreational cannabis legalization on use and inpatient outcomes of patients with inflammatory bowel disease (IBD).

Methods: Hospitalized adult patients in Colorado and Washington before (2011) and after (2015) recreational cannabis legalization were compared by chi-square tests for categorical variables and t-tests for continuous variables. Multivariable regression models adjusting for demographic data were fit to assess the association of cannabis use with hospital outcomes.

Results: Reported cannabis use increased after legalization (1.2% vs 4.2%, P < .001). On multivariable analysis, in 2011, cannabis users were less likely to need total parenteral nutrition (odds ratio 0.12, P = .038), and in 2015 had less hospital charges ($-8418, P = .024).

Conclusions: The impact of cannabis legalization and use on IBD is difficult to analyze but may have implications on inpatient IBD outcomes as described in this retrospective analysis. Large, prospective studies are needed to evaluate other IBD outcomes based on cannabis legalization and use.”

“Lay Summary

Colorado and Washington inpatient databases were analyzed before (2011) and after (2015) recreational cannabis legalization assessing use and inflammatory bowel disease outcomes. Cannabis use increased after legalization. In 2011, cannabis users were less likely to need total parenteral nutrition, and in 2015 had less hospital charges.”

The effect of medical cannabis in inflammatory bowel disease: analysis from the UK Medical Cannabis Registry

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“Objectives: Cannabis-based medicinal products (CBMPs) have shown promising preclinical activity in inflammatory bowel disease. However, clinical trials have not demonstrated significant effects on active inflammation. This study aims to analyze changes in health-related quality of life (HRQoL) and adverse events in IBD patients prescribed CBMPs.

Methods: A case series from the UK Medical Cannabis Registry was performed. Primary outcomes included changes from baseline in the Short Inflammatory Bowel Disease Questionnaire (SIBDQ), Generalized Anxiety Disorder-7 (GAD-7), Single-Item Sleep Quality Scale (SQS), and EQ-5D-5L Index score at 1 and 3 months. Statistical significance was defined using p<0.050. Secondary outcomes included incidence of adverse events.

Results: Seventy-six patients with Crohn’s disease (n=51; 67.11%) and ulcerative colitis (n=25; 32.89%) were included. The median baseline SIBDQ score improved at 1 and 3 months. EQ-5D-5L index values, GAD-7 and SQS also improved after 3 months (p<0.050). Sixteen (21.05%) patients reported adverse events with the majority being classified as mild to moderate in severity. No life-threatening AEs were reported.

Conclusion: Patients treated with CBMPs for refractory symptoms of Crohn’s disease and ulcerative colitis demonstrated a short-term improvement in IBD-specific and general HRQoL. Prior cannabis consumers reported greater improvement compared to cannabis-naïve individuals.”

Phytocannabinoids Act Synergistically with Non-Steroidal Anti-Inflammatory Drugs Reducing Inflammation in 2D and 3D In Vitro Models


“Lung inflammation is associated with elevated pro-inflammatory cytokines and chemokines. Treatment with FCBD:std (standard mix of cannabidiol [CBD], cannabigerol [CBG] and tetrahydrocannabivarin [THCV]) leads to a marked reduction in the inflammation of alveolar epithelial cells, but not in macrophages.

In the present study, the combined anti-inflammatory effect of FCBD:std with two corticosteroids (dexamethasone and budesonide) and two non-steroidal anti-inflammatory drugs (NSAID; ibuprofen and diclofenac), was examined. Enzyme-linked immunosorbent assay (ELISA) was used to determine protein levels. Gene expression was determined by quantitative real-time PCR. Inhibition of cyclo-oxygenase (COX) activity was determined in vitro.

FCBD:std and diclofenac act synergistically, reducing IL-8 levels in macrophages and lung epithelial cells. FCBD:std plus diclofenac also reduced IL-6IL-8 and CCL2 expression levels in co-cultures of macrophages and lung epithelial cells, in 2D and 3D models. Treatment by FCBD:std and/or NSAID reduced COX-1 and COX-2 gene expression but not their enzymatic activity. FCBD:std and diclofenac exhibit synergistic anti-inflammatory effects on macrophages and lung epithelial cells, yet this combined activity needs to be examined in pre-clinical studies and clinical trials.”

“We have shown that FCBD:std and diclofenac have synergistic anti-inflammatory effects on macrophages and lung epithelial cells, which involve the reduction of COX and CCL2 gene expression and IL levels. FCBD:std, when combined with diclofenac, can have considerably increased anti-inflammatory activity by several fold, suggesting that in an effective cannabis-diclofenac combined treatment, the level of NSAIDs may be reduced without compromising anti-inflammatory effectivity.”

Cannabinoid Therapeutic Effects in Inflammatory Bowel Diseases: A Systematic Review and Meta-Analysis of Randomized Controlled Trials


“Introduction: Inflammatory Bowel Disease (IBD) patients may benefit from cannabinoid administration supplementary therapy; currently no consensus on its effect has been reached.

Methods: a systematic review of RCTs on cannabinoid supplementation therapy in IBD has been conducted; data sources were MEDLINE, Scopus, ClinicalTrials.

Results: out of 974 papers found with electronic search, six studies have been included into the systematic review, and five of them, for a grand total of 208 patients, were included into the meta-analysis.

Conclusions: cannabinoid supplementation as adjuvant therapy may increase the chances of success for standard therapy of Crohn’s Disease during the induction period; no statement on its potential usage during maintenance period can be derived from retrieved evidence. Its usage in Ulcerative Colitis is not to be recommended. If ever, low-dose treatment may be more effective than higher dosage. Mean CDAI reduction was found stronger in patients treated with cannabinoids (mean CDAI reduction = 36.63, CI 95% 12.27-61.19) than placebo. In future studies, it is advisable to include disease activity levels, as well as patient-level information such as genetic and behavioral patterns.”

The Enteric Glia and Its Modulation by the Endocannabinoid System, a New Target for Cannabinoid-Based Nutraceuticals?


“The enteric nervous system (ENS) is a part of the autonomic nervous system that intrinsically innervates the gastrointestinal (GI) tract. Whereas enteric neurons have been deeply studied, the enteric glial cells (EGCs) have received less attention. However, these are immune-competent cells that contribute to the maintenance of the GI tract homeostasis through supporting epithelial integrity, providing neuroprotection, and influencing the GI motor function and sensation. The endogenous cannabinoid system (ECS) includes endogenous classical cannabinoids (anandamide, 2-arachidonoylglycerol), cannabinoid-like ligands (oleoylethanolamide (OEA) and palmitoylethanolamide (PEA)), enzymes involved in their metabolism (FAAH, MAGL, COX-2) and classical (CB1 and CB2) and non-classical (TRPV1, GPR55, PPAR) receptors. The ECS participates in many processes crucial for the proper functioning of the GI tract, in which the EGCs are involved. Thus, the modulation of the EGCs through the ECS might be beneficial to treat some dysfunctions of the GI tract. This review explores the role of EGCs and ECS on the GI tract functions and dysfunctions, and the current knowledge about how EGCs may be modulated by the ECS components, as possible new targets for cannabinoids and cannabinoid-like molecules, particularly those with potential nutraceutical use.”

“Although further studies are needed to define the connections between the ECS and EGCs as a possible target to treat or reduce alterations associated with GI disorders, the use of cannabinoids may be beneficial in prevalent pathologies such as inflammatory bowel disease (IBD) and, maybe, other types of GI pathologies displaying ENS inflammation.”

Targeting the endocannabinoid system for the treatment of abdominal pain in irritable bowel syndrome

Nature Reviews Gastroenterology & Hepatology

“The management of visceral pain in patients with disorders of gut-brain interaction, notably irritable bowel syndrome, presents a considerable clinical challenge, with few available treatment options.

Patients are increasingly using cannabis and cannabinoids to control abdominal pain. Cannabis acts on receptors of the endocannabinoid system, an endogenous system of lipid mediators that regulates gastrointestinal function and pain processing pathways in health and disease.

The endocannabinoid system represents a logical molecular therapeutic target for the treatment of pain in irritable bowel syndrome.

Here, we review the physiological and pathophysiological functions of the endocannabinoid system with a focus on the peripheral and central regulation of gastrointestinal function and visceral nociception. We address the use of cannabinoids in pain management, comparing them to other treatment modalities, including opioids and neuromodulators. Finally, we discuss emerging therapeutic candidates targeting the endocannabinoid system for the treatment of pain in irritable bowel syndrome.”

Hemp-Derived Nanovesicles Protect Leaky Gut and Liver Injury in Dextran Sodium Sulfate-Induced Colitis


“Hemp (Cannabis sativa L.) is used for medicinal purposes owing to its anti-inflammatory and antioxidant activities.

We evaluated the protective effect of nanovesicles isolated from hemp plant parts (root, seed, hemp sprout, and leaf) in dextran sulfate sodium (DSS)-induced colitis in mice.

The particle sizes of root-derived nanovesicles (RNVs), seed-derived nanovesicles (SNVs), hemp sprout-derived nanovesicles (HSNVs), and leaf-derived nanovesicles (LNVs) were within the range of 100-200 nm as measured by nanoparticle tracking analysis. Acute colitis was induced in C57BL/N mice by 5% DSS in water provided for 7 days.

RNVs were administered orally once a day, leading to the recovery of both the small intestine and colon lengths. RNVs, SNVs, and HSNVs restored the tight (ZO-1, claudin-4, occludin) and adherent junctions (E-cadherin and α-tubulin) in DSS-induced small intestine and colon injury. Additionally, RNVs markedly reduced NF-κB activation and oxidative stress proteins in DSS-induced small intestine and colon injury. Tight junction protein expression and epithelial cell permeability were elevated in RNV-, SNV-, and HSNV-treated T84 colon cells exposed to 2% DSS. Interestedly, RNVs, SNVs, HSNVs, and LNVs reduced ALT activity and liver regeneration marker proteins in DSS-induced liver injury.

These results showed for the first time that hemp-derived nanovesicles (HNVs) exhibited a protective effect on DSS-induced gut leaky and liver injury through the gut-liver axis by inhibiting oxidative stress marker proteins.”

“In summary, we successfully identified and characterized edible-plant nanovesicles from different hemp (Cannabis sativa L.) parts (root; RNVS, seed; SNVS, hemp sprout; HSNVs, leaf; LNVs). RNVs markedly alleviated leaky gut and intestinal barrier proteins such as tight junction and adherent junction proteins and reduced NF-κB activation and oxidative stress markers in DSS-induced colitis. Additionally, NVs, SNVs, HSNVs, and LNVs administration reduced liver damage markers and elevated liver regeneration markers. Therefore, this is the first study using hemp-derived nanovesicles in protection against colitis that can be a novel therapeutic strategy to treat IBD.”

Differential Effects of D9 Tetrahydrocannabinol (THC)- and Cannabidiol (CBD)-Based Cannabinoid Treatments on Macrophage Immune Function In Vitro and on Gastrointestinal Inflammation in a Murine Model


“Phytocannabinoids possess a wide range of immune regulatory properties, mediated by the endocannabinoid system.

Monocyte/macrophage innate immune cells express endocannabinoid receptors. Dysregulation of macrophage function is involved in the pathogenesis of different inflammatory diseases, including inflammatory bowel disease.

In our research, we aimed to evaluate the effects of the phytocannabinoids D9 tetrahydrocannabinol (THC) and cannabidiol (CBD) on macrophage activation.

Macrophages from young and aged C57BL/6 mice were activated in vitro in the presence of pure cannabinoids or cannabis extracts. The phenotype of the cells, nitric oxide (NO•) secretion, and cytokine secretion were examined. In addition, these treatments were administered to murine colitis model. The clinical statuses of mice, levels of colon infiltrating macrophages, and inflammatory cytokines in the blood, were evaluated.

We demonstrated inhibition of macrophage NO• and cytokine secretion and significant effects on expression of cell surface molecules. In the murine model, clinical scores were improved and macrophage colon infiltration reduced following treatment. We identified higher activity of cannabis extracts as compared with pure cannabinoids. Each treatment had a unique effect on cytokine composition.

Overall, our results establish that the effects of cannabinoid treatments differ. A better understanding of the reciprocal relationship between cannabinoids and immunity is essential to design targeted treatment strategies.”

“Overall, our results indicate both similarities and differences between the impact of CBD- and THC-based drugs. Although all the tested treatments had an anti-inflammatory effect, their specific effects (for example, on phenotype of the cells and on cytokine production) differed. These differences may influence the clinical outcome of the treatment. We were surprised to find very similar anti-inflammatory results for the two cannabis extracts, which had diverse content of THC and CBD. This could suggest that THC/CBD content may not be the best indicator for anti-inflammatory properties of a cannabis-based drug. These results highlight the need to expand the research on the interplay between cannabinoids and other phytochemicals in the cannabis extracts. A better understanding of the effects of each molecule and the synergism between these molecules on the immune response will assist physicians to provide the best possible individually targeted treatment for their patients and will allow the design of new treatments.”

Involvement of the cannabinoid system in chronic inflammatory intestinal diseases: opportunities for new therapies

Intestinal Research

“The components of the endogenous cannabinoid system are widely expressed in the gastrointestinal tract contributing to local homeostasis. In general, cannabinoids exert inhibitory actions in the gastrointestinal tract, inducing anti-inflammatory, antiemetic, antisecretory, and antiproliferative effects. Therefore, cannabinoids are interesting pharmacological compounds for the treatment of several acute intestinal disorders, such as dysmotility, emesis, and abdominal pain. Likewise, the role of cannabinoids in the treatment of chronic intestinal diseases, such as irritable bowel syndrome and inflammatory bowel disease, is also under investigation. Patients with chronic intestinal inflammatory diseases present impaired quality of life, and mental health issues are commonly associated with long-term chronic diseases. The complex pathophysiology of these diseases contributes to difficulties in diagnosis and, therefore, in the choice of a satisfactory treatment. Thus, this article reviews the involvement of the cannabinoid system in chronic inflammatory diseases that affect the gastrointestinal tract and highlights possible therapeutic approaches related to the use of cannabinoids.”