Cannabinoids and the gut: new developments and emerging concepts

Overview of cannabidiol (CBD) and its analogues: Structures, biological activities, and neuroprotective mechanisms in epilepsy and Alzheimer's disease

Herein, 11 general types of natural cannabinoids from Cannabis sativa as well as 50 (-)-CBD analogues with therapeutic potential were described. The underlying molecular mechanisms of CBD as a therapeutic candidate for epilepsy and neurodegenerative diseases were comprehensively clarified. CBD indirectly acts as an endogenous cannabinoid receptor agonist to exert its neuroprotective effects. CBD also promotes neuroprotection through different signal transduction pathways mediated indirectly by cannabinoid receptors. Furthermore, CBD prevents the glycogen synthase kinase 3β (GSK-3β) hyperphosphorylation caused by Aβ and may be developed as a new therapeutic candidate for Alzheimer's disease.

Signaling molecules targeting cannabinoid receptors: Hemopressin and related peptides

Cannabinoid receptors (CBRs) are part of the endocannabinoid system, which is involved in various physiological processes such as nociception, inflammation, appetite, stress, and emotion regulation. Many studies have linked the endocannabinoid system to neuroinflammatory and neurodegenerative disorders such as Parkinson's disease, Huntington's chorea, Alzheimer's disease, and multiple sclerosis. Hemopressin [Hp; a fragment of the hemoglobin α1 chain (95-103 amino acids)] and related peptides [VD-Hpα and RVD-Hpα] are peptides that bind to CBRs. Hp acts as an inverse agonist to CB₁ receptor (CB₁R), VD-Hpα acts as an agonist to CB₁R, and RVD-Hpα acts as a negative allosteric modulator of CB₁R and a positive allosteric modulator of CB₂R. Because of the critical roles of CBRs in numerous physiological processes, it is appealing to use Hp and related peptides for therapeutic purposes. This review discusses their discovery, structure, metabolism, brain exposure, self-assembly characteristics, pharmacological characterization, and pharmacological activities.

Relationship of Cannabis Use Disorder and Irritable Bowel Syndrome (IBS): An Analysis of 6.8 Million Hospitalizations in the United States

Background: Irritable bowel syndrome (IBS) is a chronic multifactorial gastrointestinal condition that substantially affects the quality of life. Research have suggested an increasing trend in cannabis use to alleviate IBS-related psychiatric symptoms. Objectives: We aim to investigate the association of psychiatric comorbidities and cannabis use disorders (CUD) in hospitalized IBS patients. Methods: We analyzed 31,272 IBS hospitalizations in patients (aged 15-54 years) from the Nationwide Inpatient Sample (NIS). We utilized logistic regression to evaluate the adjusted odds ratio (aOR) of CUD and psychiatric comorbidities. Results: Anxiety (26.3%) and depressive (24.8%) disorders were prevalent and increased the odds for IBS-hospitalization by 2.5 and 1.8 times respectively. Tobacco use disorder was most prevalent (24.5%) followed by CUD (3.7%). After controlling for demographics, psychiatric and medical comorbidities, and other substance use disorders, CUD had higher odds for IBS hospitalizations (aOR 1.407, 95% CI 1.32-1.50). IBS hospitalizations with CUD increased by 32.8% from 2010 to 2014. CUD patients were younger (15-24 years, aOR 5.4, 95% CI 4.27-6.77), males (aOR 1.8, 95% CI 1.59-2.09) and African Americans (aOR 2.8, 95% CI 1.45-2.23) and from low-income families (aOR 1.9, 95% CI 1.58-2.39). Conclusions: We found that patients with CUD have 40.7% higher odds for IBS-hospitalizations with a rising trend of CUD and related psychiatric comorbidities which may further worsen IBS and health quality of life. With limited evidence of efficacy and safety of cannabis in IBS, larger, randomized controlled studies are required to examine its therapeutic efficacy.

Fatigue in Inflammatory Bowel Diseases: Etiologies and Management

Fatigue is a burdensome, multidimensional, and multifactorial symptom that is associated with a wide array of chronic illnesses, specifically occurring in nearly 50% of patients with inflammatory bowel disease (IBD). Although common, given its subjective nature, physicians often under-recognize and undertreat this debilitating symptom. There are multiple etiologies that can contribute to fatigue in patients with IBD, including disease activity, anemia, medications, psychosomatic symptoms, and alterations to the gut–brain axis. The management of fatigue in IBD can be challenging, as it is often times multifaceted. In this review, we summarize the available tools for the diagnosis and measurement of fatigue, discuss etiologies, and make recommendations for their management. We identify knowledge gaps for the workup and treatment of fatigue and propose an algorithm to aid physicians in the evaluation and management of fatigue in this unique population. However, future research is needed to address several areas of knowledge deficits and improve the management of fatigue in IBD.

Cannabinoids and the Microbiota-Gut-Brain Axis: Emerging Effects of Cannabidiol and Potential Applications to Alcohol Use Disorders

The endocannabinoid system (ECS) has emerged in recent years as a potential treatment target for alcohol use disorders (AUD). In particular, the nonpsychoactive cannabinoid cannabidiol (CBD) has shown preclinical promise in ameliorating numerous clinical symptoms of AUD. There are several proposed mechanism(s) through which cannabinoids (and CBD in particular) may confer beneficial effects in the context of AUD. First, CBD may directly impact specific brain mechanisms underlying AUD to influence alcohol consumption and the clinical features of AUD. Second, CBD may influence AUD symptoms through its actions across the digestive, immune, and central nervous systems, collectively known as the microbiota-gut-brain axis (MGBA). Notably, emerging work suggests that alcohol and cannabinoids exert opposing effects on the MGBA. Alcohol is linked to immune dysfunction (e.g., chronic systemic inflammation in the brain and periphery) as well as disturbances in gut microbial species (microbiota) and increased intestinal permeability. These MGBA disruptions have been associated with AUD symptoms such as craving and impaired cognitive control. Conversely, existing preclinical data suggest that cannabinoids may confer beneficial effects on the gastrointestinal and immune system, such as reducing intestinal permeability, regulating gut bacteria, and reducing inflammation. Thus, cannabinoids may exert AUD harm-reduction effects, at least in part, through their beneficial actions across the MGBA. This review will provide a brief introduction to the ECS and the MGBA, discuss the effects of cannabinoids (particularly CBD) and alcohol in the brain, gut, and immune system (i.e., across the MGBA), and put forth a theoretical framework to inform future research questions.

Missing Pieces to the Endocannabinoid Puzzle

The most bioactive ingredient of cannabis (Cannabis sativa or indica) extracts, Δ⁹-tetrahydrocannabinol (THC), was identified in the 1960s as one of more than 110 phytocannabinoids. It activates receptors of chemically different endogenous ligands (endocannabinoids) that, unlike THC, are metabolized by several enzymes of the endocannabinoid system. Here, the complexity of the plant-derived and endogenous cannabinoids (eCBs) is discussed, to better appreciate the challenge of: (i) dissecting their mutual interactions; (ii) understanding their impact on human pathophysiology; and (iii) exploiting them for human disease. To this aim, missing pieces to the eCB puzzle must be urgently found, by solving the 3D structures of key components, and interrogating noncanonical modes of regulation and trafficking of these lipid signals.

Endocannabinoid system in irritable bowel syndrome and cannabis as a therapy

Irritable bowel syndrome (IBS) global burden is underestimated despite its high prevalence. It's a gastrointestinal disease having obscure pathophysiology with multiple therapies yet unsatisfactory remedies. The Endocannabinoid system (ECS) of our body plays a key role in maintaining normal physiology of the gastrointestinal tract as well as involves abnormalities including functional diseases like IBS. This review highlights the importance of the Endocannabinoid system, its connections with the normal gastrointestinal functions and abnormalities like IBS. It also discusses the role of cannabis as medical therapy in IBS patients. A literature search for articles related to endocannabinoids in IBS and medical cannabis in PubMed and Google Scholar was conducted. The studies highlighted the significant participation of ECS in IBS. However, the breach in obtaining the promising therapeutic model for IBS needed further investigation in ECS and uncover other treatments for IBS. This review summarizes ECS, highlights the relationship of ECS with IBS and explores cannabis as a potential therapy to treat IBS.

Herbal medicinal products for inflammatory bowel disease: A focus on those assessed in double-blind randomised controlled trials

Inflammatory bowel disease patients frequently use herbal products as complementary or alternative medicines to current pharmacotherapies and obtain information on them mainly from the internet, social media, or unlicensed practitioners. Clinicians should therefore take a more active role and become knowledgeable of the mechanisms of action and potential drug interactions of herbal medicines for which evidence of efficacy is available. The therapeutic efficacy and safety of several herbal medicines have been studied in double-blind randomised controlled trials (RCTs). Evidence of efficacy is available for Andrographis paniculata extract; curcumin; a combination of myrrh, extract of chamomile flower, and coffee charcoal; and the Chinese herbal medicines Fufangkushen colon-coated capsule and Xilei san in patients with ulcerative colitis; and Artemisia absinthium extract and Boswellia serrata resin extract in patients with Crohn's disease. However, most of this evidence comes from single small RCTs with short follow-up, and the long-term effects and safety of their use have not yet been established. Thus, our findings indicate that further appropriately sized RCTs are necessary prior to the recommended use of these herbal medicines in therapy. In the meantime, increasing awareness of their use, and potential drug interactions among physicians may help to reduce unwanted effects and adverse disease outcomes.

Roles of the Hepatic Endocannabinoid and Apelin Systems in the Pathogenesis of Liver Fibrosis

Hepatic fibrosis is the consequence of an unresolved wound healing process in response to chronic liver injury and involves multiple cell types and molecular mechanisms. The hepatic endocannabinoid and apelin systems are two signalling pathways with a substantial role in the liver fibrosis pathophysiology-both are upregulated in patients with advanced liver disease. Endogenous cannabinoids are lipid-signalling molecules derived from arachidonic acid involved in the pathogenesis of cardiovascular dysfunction, portal hypertension, liver fibrosis, and other processes associated with hepatic disease through their interactions with the CB₁ and CB₂ receptors. Apelin is a peptide that participates in cardiovascular and renal functions, inflammation, angiogenesis, and hepatic fibrosis through its interaction with the APJ receptor. The endocannabinoid and apelin systems are two of the multiple cell-signalling pathways involved in the transformation of quiescent hepatic stellate cells into myofibroblast like cells, the main matrix-producing cells in liver fibrosis. The mechanisms underlying the control of hepatic stellate cell activity are coincident despite the marked dissimilarities between the endocannabinoid and apelin signalling pathways. This review discusses the current understanding of the molecular and cellular mechanisms by which the hepatic endocannabinoid and apelin systems play a significant role in the pathophysiology of liver fibrosis.

Insights into the role of cannabis in the management of inflammatory bowel disease

Over the last decade, interest in the therapeutic potential of cannabis and its constituents (e.g. cannabidiol) in the management of inflammatory bowel diseases (IBD) has escalated. Cannabis has been increasingly approved for a variety of medical conditions in several jurisdictions around the world. In animal models, cannabinoids have been shown to improve intestinal inflammation in experimental models of IBD through their interaction with the endocannabinoid system. However, the few randomized controlled trials of cannabis or cannabidiol in patients with IBD have not demonstrated efficacy in modulating inflammatory disease activity. Cannabis may be effective in the symptomatic management of IBD. Given the increasing utilization and cultural acceptance of cannabis, physicians need to be aware of its safety and efficacy in order to better counsel patients. The aim of this review is to provide an overview of the role of cannabis in the management of patients with IBD.

Food database of N-acyl-phosphatidylethanolamines, N-acylethanolamines and endocannabinoids and daily intake from a Western, a Mediterranean and a vegetarian diet

The contents of N-acylphosphatidylethanolamines (NAPEs), N-acylethanolamines (NAEs) and endocannabinoids (ECs) in 43 food products were assessed and daily intakes, based on consumption of Mediterranean, vegetarian and Western diets, were simulated. NAPEs and NAEs were more abundant in plant-based foods than in animal food products; NAPEs were in the ranges 0-4032 vs 4-398 µg/g dw and NAEs were in the ranges 0-35 vs 0.1-0.7 µg/g dw, respectively while ECs were in the range 0-0.1 vs 0-34 µg/g dw. Daily intakes of NAPEs and NAEs were higher from Mediterranean (263 and 0.25 mg/day) and vegetarian (242 and 0.28 mg/day) diets than the Western diet (163 and 0.08 mg/day). Conversely, ECs intakes were higher from Western and Mediterranean diets (0.17 mg/day) than the vegetarian diet (0.01 mg/day). Future studies will evaluate the physiological role of dietary NAPEs, NAEs and ECs in humans.

Higher odds of irritable bowel syndrome among hospitalized patients using cannabis: a propensity-matched analysis

BACKGROUND

The endogenous cannabinoid system modulates many brain-gut and gut-brain physiologic pathways, which are postulated to be dysfunctional in irritable bowel syndrome (IBS). Herein, we examine the relationship between cannabis use disorder (CUD) and having IBS.

PATIENTS AND METHODS

After selecting patients aged 18 years and above from the 2014 Nationwide Inpatient Survey, we used the International Classification of Diseases, 9th ed. codes to identify individuals with CUD, IBS, and the established risk factors for IBS. We then estimated the crude and adjusted odds ratios of having a diagnosis of IBS with CUD and assessed for the interactions of CUD with other risk factors (SAS 9.4). We confirmed our findings in two ways: conducting a similar analysis on a previous Nationwide Inpatient Survey data (2012); and using a greedy algorithm to design a propensity-scored case-control (1 : 10) study, approximating a pseudorandomized clinical trial.

RESULTS

Out of 4 709 043 patients evaluated, 0.03% had a primary admission for IBS and 1.32% had CUD. CUD was associated with increased odds of IBS [adjusted odds ratio: 2.03; 95% confidence interval (CI): 1.53-2.71]. CUD was related to higher odds for IBS among males compared with females (3.48; 1.98-6.12 vs. 1.48; 0.88-2.50), and Hispanics and Caucasians compared with Blacks (5.28; 1.77-15.76, 1.80; 1.02-3.18 vs. 1.80; 0.65-5.03). On propensity-matching, CUD was associated with 80% increased odds for IBS (1.82; 1.27-2.60).

CONCLUSION

Our findings suggest that CUD is significantly associated with IBS among the general population. Males, Caucasians, and Hispanics might be more impacted by CUD associated IBS. Additional biomedical studies are required to elucidate this relationship.

Role of Cannabinoid Receptor Type 1 in Insulin Resistance and Its Biological Implications

Endogenous cannabinoids (ECs) are lipid-signaling molecules that specifically bind to cannabinoid receptor types 1 and 2 (CB1R and CB2R) and are highly expressed in central and many peripheral tissues under pathological conditions. Activation of hepatic CB1R is associated with obesity, insulin resistance, and impaired metabolic function, owing to increased energy intake and storage, impaired glucose and lipid metabolism, and enhanced oxidative stress and inflammatory responses. Additionally, blocking peripheral CB1R improves insulin sensitivity and glucose metabolism and also reduces hepatic steatosis and body weight in obese mice. Thus, targeting EC receptors, especially CB1R, may provide a potential therapeutic strategy against obesity and insulin resistance. There are many CB1R antagonists, including inverse agonists and natural compounds that target CB1R and can reduce body weight, adiposity, and hepatic steatosis, and those that improve insulin sensitivity and reverse leptin resistance. Recently, the use of CB1R antagonists was suspended due to adverse central effects, and this caused a major setback in the development of CB1R antagonists. Recent studies, however, have focused on development of antagonists lacking adverse effects. In this review, we detail the important role of CB1R in hepatic insulin resistance and the possible underlying mechanisms, and the therapeutic potential of CB1R targeting is also discussed.

Cannabis, Cannabinoids, and the Endocannabinoid System-Is there Therapeutic Potential for Inflammatory Bowel Disease?

Cannabis sativa and its extracts have been used for centuries, both medicinally and recreationally. There is accumulating evidence that exogenous cannabis and related cannabinoids improve symptoms associated with inflammatory bowel disease [IBD], such as pain, loss of appetite, and diarrhoea. In vivo, exocannabinoids have been demonstrated to improve colitis, mainly in chemical models. Exocannabinoids signal through the endocannabinoid system, an increasingly understood network of endogenous lipid ligands and their receptors, together with a number of synthetic and degradative enzymes and the resulting products. Modulating the endocannabinoid system using pharmacological receptor agonists, genetic knockout models, or inhibition of degradative enzymes have largely shown improvements in colitis in vivo. Despite these promising experimental results, this has not translated into meaningful benefits for human IBD in the few clinical trials which have been conducted to date, the largest study being limited by poor medication tolerance due to the Δ9-tetrahydrocannabinol component. This review article synthesises the current literature surrounding the modulation of the endocannabinoid system and administration of exocannabinoids in experimental and human IBD. Findings of clinical surveys and studies of cannabis use in IBD are summarised. Discrepancies in the literature are highlighted together with identifying novel areas of interest.

Brain activity of anandamide: a rewarding bliss?

Anandamide is a lipid mediator that acts as an endogenous ligand of CB1 receptors. These receptors are also the primary molecular target responsible for the pharmacological effects of Δ9-tetrahydrocannabinol, the psychoactive ingredient in Cannabis sativa. Several studies demonstrate that anandamide exerts an overall modulatory effect on the brain reward circuitry. Several reports suggest its involvement in the addiction-producing actions of other abused drugs, and it can also act as a behavioral reinforcer in animal models of drug abuse. Importantly, all these effects of anandamide appear to be potentiated by pharmacological inhibition of its metabolic degradation. Enhanced brain levels of anandamide after treatment with inhibitors of fatty acid amide hydrolase, the main enzyme responsible for its degradation, seem to affect the rewarding and reinforcing actions of many drugs of abuse. In this review, we will provide an overview from a preclinical perspective of the current state of knowledge regarding the behavioral pharmacology of anandamide, with a particular emphasis on its motivational/reinforcing properties. We will also discuss how modulation of anandamide levels through inhibition of enzymatic metabolic pathways could provide a basis for developing new pharmaco-therapeutic tools for the treatment of substance use disorders.

Activity in nodose ganglia neurons after treatment with CP 55,940 and cholecystokinin

Previous work has shown that cannabinoids increase feeding, while cholecystokinin (CCK) has an anorexigenic effect on food intake. Receptors for these hormones are located on cell bodies of vagal afferent nerves in the nodose ganglia. An interaction between CCK and endocannabinoid receptors has been suggested. The purpose of these studies is to explore the effect of pretreatment with a cannabinoid agonist, CP 55,940, on nodose neuron activation by CCK. To determine the effect of CP 55,940 and CCK on neuron activation, rats were anesthetized and nodose ganglia were excised. The neurons were dissociated and placed in culture on coverslips. The cells were treated with media; CP 55,940; CCK; CP 55,940 followed by CCK; or AM 251, a CB1 receptor antagonist, and CP 55,940 followed by CCK. Immunohistochemistry was performed to stain the cells for cFos as a measure of cell activation. Neurons were identified using neurofilament immunoreactivity. The neurons on each slip were counted using fluorescence imaging, and the number of neurons that were cFos positive was counted in order to calculate the percentage of activated neurons per coverslip. Pretreatment with CP 55,940 decreased the percentage of neurons expressing cFos-immunoreactivity in response to CCK. This observation suggests that cannabinoids inhibit CCK activation of nodose ganglion neurons.

Design, Synthesis, and SAR Studies of Heteroarylpyrimidines and Heteroaryltriazines as CB2 R Ligands

Herein we describe the design and synthesis of a new series of heteroarylpyrimidine/heteroaryltriazine derivatives on the basis of quinazoline-2,4(1H,3H)-diones as CB₂ R-selective ligands using a bioisosterism strategy. An acetamide group was explored to displace the enamine linker of the lead compound for the purpose of stereoisomerism elimination and hydrophilicity increase. As a result, some of the synthesized compounds showed high bioactivity and selectivity for CB₂ R in calcium mobilization assays, and four displayed CB₂ R agonist activity, with EC₅₀ values below 30 nm. The compound exhibiting the highest agonist activity toward CB₂ R (EC₅₀ =7.53±3.15 nm) had a selectivity over CB₁ R of more than 1328-fold. Moreover, structure-activity relationship (SAR) studies indicated that the substituents on the nucleus play key roles in the functionality of a ligand, with one such example demonstrating CB₂ R antagonist activity. Additionally, molecular docking simulations were conducted with the aim of better understanding of these new derivatives in relation to the structural requirements for agonists/antagonists binding to CB₂ R.

Host- and Helminth-Derived Endocannabinoids That Have Effects on Host Immunity Are Generated during Infection

Helminths have coevolved with their hosts, resulting in the development of specialized host immune mechanisms and parasite-specific regulatory products. Identification of new pathways that regulate helminth infection could provide a better understanding of host-helminth interaction and may identify new therapeutic targets for helminth infection. Here we identify the endocannabinoid system as a new mechanism that influences host immunity to helminths. Endocannabinoids are lipid-derived signaling molecules that control important physiologic processes, such as feeding behavior and metabolism. Following murine infection with Nippostrongylus brasiliensis, an intestinal nematode with a life cycle similar to that of hookworms, we observed increased levels of endocannabinoids (2-arachidonoylglycerol [2-AG] or anandamide [AEA]) and the endocannabinoid-like molecule oleoylethanolamine (OEA) in infected lung and intestine. To investigate endocannabinoid function in helminth infection, we employed pharmacological inhibitors of cannabinoid subtype receptors 1 and 2 (CB₁R and CB₂R). Compared to findings for vehicle-treated mice, inhibition of CB₁R but not CB₂R resulted in increased N. brasiliensis worm burden and egg output, associated with significantly decreased expression of the T helper type 2 cytokine interleukin 5 (IL-5) in intestinal tissue and splenocyte cultures. Strikingly, bioinformatic analysis of genomic and transcriptome sequencing (RNA-seq) data sets identified putative genes encoding endocannabinoid biosynthetic and degradative enzymes in many parasitic nematodes. To test the novel hypothesis that helminth parasites produce their own endocannabinoids, we measured endocannabinoid levels in N. brasiliensis by mass spectrometry and quantitative PCR and found that N. brasiliensis parasites produced endocannabinoids, especially at the infectious larval stage. To our knowledge, this is the first report of helminth- and host-derived endocannabinoids that promote host immune responses and reduce parasite burden.

Impact of maternal western diet-induced obesity on offspring mortality and peripheral endocannabinoid system in mice

Over two-thirds of adults in the United States are obese or overweight, which is largely due to chronic overconsumption of diets high in fats and sugars (i.e., Western diet). Recent studies reveal that maternal obesity may predispose offspring to development of obesity and other metabolic diseases; however, the molecular underpinnings of these outcomes are largely unknown. The endocannabinoid system is an important signaling pathway that controls feeding behavior and energy homeostasis, and its activity becomes upregulated in the upper small intestinal epithelium of Western diet-induced obese mice, which drives overeating. In the current investigation, we examined the impact of chronic maternal consumption of Western diet on the expression and function of the endocannabinoid system in several peripheral organs important for food intake and energy homeostasis in offspring. Female C57BL/6Tac mice were fed a Western diet or low-fat/no-sucrose control chow for 10 weeks, then males were introduced for mating. Dams were maintained on their respective diets through weaning of pups, at which time pups were maintained on low-fat/no-sucrose chow for 10 weeks. Neonates born from dams fed Western diet, when compared to those born from mice fed control chow, unexpectedly displayed increases in mortality that occurred exclusively within six days following birth (greater than 50% mortality). Males comprised a larger fraction of surviving offspring from obese dams. Furthermore, surviving offspring displayed transient increases in body mass for first two days post weaning, and no marked changes in feeding patterns and endocannabinoid levels in upper small intestinal epithelium, pancreas, and plasma, or in expression of key endocannabinoid system genes in the upper small intestinal epithelium and pancreas at 10 weeks post-weaning. Collectively, these results suggest that maternal diet composition greatly influences survival of neonate C57BL/6Tac mice, and that surviving offspring from dams chronically fed a Western diet do not display marked changes in body mass, eating patterns, or expression and function of the endocannabinoid system in several peripheral organs important for feeding behavior and energy homeostasis.

Recurrent Nausea and Vomiting in a Pregnant Woman with Chronic Marijuana Use

Background

Cannabinoid hyperemesis syndrome is a condition characterized by chronic cannabis use and cyclic episodes of nausea, vomiting, and abdominal pain, relieved by compulsive bathing. The syndrome is likely to be underdiagnosed in pregnant women due to its similarity with hyperemesis gravidarum in the presentation.

Case

We report a 20-year-old pregnant woman with multiple admissions for recurrent nausea and vomiting who was observed to be taking frequent hot showers. Without other identifiable causes, she was diagnosed with cannabinoid hyperemesis syndrome and managed with antiemetics and abstinence.

Conclusion

Abstinence from cannabis use is highly recommended in pregnant women due to its potential harm in fetal development and stimulation of intractable nausea and vomiting. Recognizing the symptoms and proper history taking prompt early diagnosis, allowing timely and adequate treatment.

The novel peripherally active cannabinoid type 1 and serotonin type 3 receptor agonist AM9405 inhibits gastrointestinal motility and reduces abdominal pain in mouse models mimicking irritable bowel syndrome

The endocannabinoid system (ECS) plays a crucial role in numerous physiological processes in the central and peripheral nervous systems. In the gastrointestinal (GI) tract, selective cannabinoid (CB) receptor agonists exert potent inhibitory actions on motility and pain signalling. In the present study, we used mouse models of diarrhea, hypermotility, and abdominal pain to examine whether a novel synthetic CB₁ receptor agonist AM9405 [(2-(2,6-dihydroxy-4-(2-methyloctan-2-yl)phenyl)-1,3-dimethyl-1H-benzo[d]imidazol-3-ium bromide); also known as GAT379] exhibits effects of potential therapeutic relevance. AM9405 significantly slowed mouse intestinal motility in physiological conditions. Moreover, AM9405 reversed hypermotility and reduced pain in mouse models mimicking symptoms of functional GI disorders, such as stress-induced diarrhea and writhing test. Interestingly, some of the effects of AM9405 were blocked by a 5-HT₃ antagonist suggesting interaction with 5-HT₃ receptors. In our study we show that combining CB₁ agonism with 5-HT₃ agonism may alter physiological functions and experimental pathophysiologies in a manner that make such compounds promising drugs for the future treatment of functional GI disorders.

Intestinal P-glycoprotein exports endocannabinoids to prevent inflammation and maintain homeostasis

Neutrophil influx into the intestinal lumen is a critical response to infectious agents, but is also associated with severe intestinal damage observed in idiopathic inflammatory bowel disease. The chemoattractant hepoxilin A3, an eicosanoid secreted from intestinal epithelial cells by the apically restricted efflux pump multidrug resistance protein 2 (MRP2), mediates this neutrophil influx. Information about a possible counterbalance pathway that could signal the lack of or resolution of an apical inflammatory signal, however, has yet to be described. We now report a system with such hallmarks. Specifically, we identify endocannabinoids as the first known endogenous substrates of the apically restricted multidrug resistance transporter P-glycoprotein (P-gp) and reveal a mechanism, which we believe is novel, for endocannabinoid secretion into the intestinal lumen. Knockdown or inhibition of P-gp reduced luminal secretion levels of N-acyl ethanolamine-type endocannabinoids, which correlated with increased neutrophil transmigration in vitro and in vivo. Additionally, loss of CB2, the peripheral cannabinoid receptor, led to increased pathology and neutrophil influx in models of acute intestinal inflammation. These results define a key role for epithelial cells in balancing the constitutive secretion of antiinflammatory lipids with the stimulated secretion of proinflammatory lipids via surface efflux pumps in order to control neutrophil infiltration into the intestinal lumen and maintain homeostasis in the healthy intestine.

Cannabinoid pharmacology and therapy in gut disorders

Cannabis sp. and their products (marijuana, hashish…), in addition to their recreational, industrial and other uses, have a long history for their use as a remedy for symptoms related with gastrointestinal diseases. After many reports suggesting these beneficial effects, it was not surprising to discover that the gastrointestinal tract expresses endogenous cannabinoids, their receptors, and enzymes for their synthesis and degradation, comprising the so-called endocannabinoid system. This system participates in the control of tissue homeostasis and important intestinal functions like motor and sensory activity, nausea, emesis, the maintenance of the epithelial barrier integrity, and the correct cellular microenvironment. Thus, different cannabinoid-related pharmacological agents may be useful to treat the main digestive pathologies. To name a few examples, in irritable bowel syndrome they may normalize dysmotility and reduce pain, in inflammatory bowel disease they may decrease inflammation, and in colorectal cancer, apart from alleviating some symptoms, they may play a role in the regulation of the cell niche. This review summarizes the main recent findings on the role of cannabinoid receptors, their synthetic or natural ligands and their metabolizing enzymes in normal gastrointestinal function and in disorders including irritable bowel syndrome, inflammatory bowel disease, colon cancer and gastrointestinal chemotherapy-induced adverse effects (nausea/vomiting, constipation, diarrhea).

Marijuana Use by Adolescents and Young Adults with Inflammatory Bowel Disease

OBJECTIVE

To evaluate marijuana use by adolescents and young adults with inflammatory bowel disease (IBD).

STUDY DESIGN

This descriptive cross-sectional study of patients seen between December 2015 through June 2017 at Children's Hospital Colorado for IBD enrolled patients 13-23 years of age, independent of marijuana use status. Information obtained consisted of chart review, electronic and interview self-report, and serum cannabinoid levels. Marijuana ever-users were compared with never-users for clinical characteristics and perceptions of risk with use; users provided information on routes, patterns, motivations, and perceived benefits and problems with use.

RESULTS

Of 99 participants, ever-use was endorsed by 32% (32 of 99) and daily or almost daily use by 9% (9 of 99). Older age was the only characteristic related to endorsing marijuana use. Twenty-nine ever-users completed all questionnaires. After adjusting for age, users were 10.7 times more likely to perceive low risk of harm with regular use (P < .001). At least 1 medical reason for use was endorsed by 57% (17 of 30), most commonly for relief of physical pain (53%, 16 of 30) (2 did not complete all questionnaires). Problems from use were identified by 37% (11 of 30), most commonly craving/strong urge to use. Most common route of use was smoking (83%) followed by edibles (50%), dabbing (40%), and vaping (30%).

CONCLUSIONS

Marijuana use by adolescents and young adults with IBD is common and perceived as beneficial. Guidelines for screening, testing, and counseling of marijuana use should be developed for patients with IBD.

Therapeutic applications of cannabinoids

The psychoactive property of cannabinoids is well known and there has been a continuous controversy regarding the usage of these compounds for therapeutic purposes all over the world. Their use for medical and research purposes are restricted in various countries. However, their utility as medications should not be overshadowed by its negative physiological activities. This review article is focused on the therapeutic potential and applications of phytocannabinoids and endocannabinoids. We further highlights their mode of action, overall effects on physiology, various in vitro and in vivo studies that have been done so far and the extent to which these compounds can be useful in different disease conditions such as cancer, Alzheimer's disease, multiple sclerosis, pain, inflammation, glaucoma and many others. Thus, this work is an attempt to make the readers understand the positive implications of these compounds and indicates the significant developments of utilizing cannabinoids as therapeutic agents.

Profiles of Patients Who Use Marijuana for Inflammatory Bowel Disease

BACKGROUND

Marijuana is legal in a number of states for indications that include inflammatory bowel diseases (IBD), and patients are interested in its potential benefits.

AIMS

We aimed to describe the legal use of marijuana in individuals with IBD in the USA who participate within the CCFA Partners internet-based cohort.

METHODS

A total of 2357 participants who lived in states where prescription or recreational marijuana was legal, were offered the opportunity to complete a survey on marijuana use and IBD symptoms including perceived benefits of therapy. Bivariate statistics and logistic regression models were used to determine factors associated with marijuana use.

RESULTS

Surveys were completed by 1666 participants (71%) with only 214 (12.8%) indicating they had asked their medical doctor about its use and 73 actually using prescribed marijuana (4.4%). Within the respondent group (N = 1666), 234 participants lived where both medical and recreational marijuana is legal and 49 (20.9%) reported recreational marijuana use specifically for IBD. Users reported positive benefits (80.7%), but users also reported more depression, anxiety, pain interference, and lower social satisfaction than non-users. Those prescribed marijuana reported more active disease, and more use of steroids, narcotics, and zolpidem.

CONCLUSIONS

Few IBD patients consulted their medical doctors about marijuana use or used prescription marijuana. Where recreational marijuana was available, usage rates were higher. Users reported benefits but also more IBD symptoms, depression, anxiety, and pain. Marijuana use may be higher in patients with IBD symptoms not well treated by conventional medical approaches.

Endocannabinoids in Body Weight Control

Maintenance of body weight is fundamental to maintain one's health and to promote longevity. Nevertheless, it appears that the global obesity epidemic is still constantly increasing. Endocannabinoids (eCBs) are lipid messengers that are involved in overall body weight control by interfering with manifold central and peripheral regulatory circuits that orchestrate energy homeostasis. Initially, blocking of eCB signaling by first generation cannabinoid type 1 receptor (CB1) inverse agonists such as rimonabant revealed body weight-reducing effects in laboratory animals and men. Unfortunately, rimonabant also induced severe psychiatric side effects. At this point, it became clear that future cannabinoid research has to decipher more precisely the underlying central and peripheral mechanisms behind eCB-driven control of feeding behavior and whole body energy metabolism. Here, we will summarize the most recent advances in understanding how central eCBs interfere with circuits in the brain that control food intake and energy expenditure. Next, we will focus on how peripheral eCBs affect food digestion, nutrient transformation and energy expenditure by interfering with signaling cascades in the gastrointestinal tract, liver, pancreas, fat depots and endocrine glands. To finally outline the safe future potential of cannabinoids as medicines, our overall goal is to address the molecular, cellular and pharmacological logic behind central and peripheral eCB-mediated body weight control, and to figure out how these precise mechanistic insights are currently transferred into the development of next generation cannabinoid medicines displaying clearly improved safety profiles, such as significantly reduced side effects.

Cannabinoid Receptor 2 Functional Variant Contributes to the Risk for Pediatric Inflammatory Bowel Disease

GOALS

We conducted a case-control association analysis to establish the role of a common CB2 functional variant, Q63R, in the susceptibility to inflammatory bowel disease (IBD).

BACKGROUND

Endocannabinoids may limit intestinal inflammation through cannabinoid receptor 1 and/or 2 (CB1, CB2).

STUDY

We genotyped 217 pediatric IBD patients [112 Crohn's disease (CD), 105 ulcerative colitis (UC)] and 600 controls for the CB2-Q63R variant by Taqman assay. Data were collected from clinical records on age at diagnosis, disease activity, duration and location, extraintestinal manifestations, therapy, clinical relapses, and need for surgery.

RESULTS

We found a significant association of the CB2-R63 variant with IBD (allele frequencies, P=0.04; genotype distributions, P=0.0006), in particular with CD (allele frequencies, P=0.002; genotype distributions, P=0.00005) and with UC only for genotype distributions (P=0.03). RR carriers showed an increased risk for developing IBD [odds ratio (OR)=1.82; P=0.0002 for IBD; OR=2.02; P=10 for CD; OR=1.63; P=0.02 for UC at 95% confidence interval]. Upon genotype-phenotype evaluation, RR patients showed an increased frequency of moderate-to-severe disease activity at diagnosis in the case of both CD and UC (P=0.01 and P=0.02, respectively) and also an earlier clinical relapse in UC (P=0.04). In UC, all the clinical features related to the CB2 risk allele were still significantly associated with the variant when analyzed using a multivariate logistic regression model (P=0.001).

CONCLUSIONS

The CB2-Q63R variant contributes to the risk for pediatric IBD, in particular CD. The R63 variant is associated with a more severe phenotype in both UC and CD. Taken together, our data point toward the involvement of the CB2 receptor in the pathogenesis and clinical features of pediatric IBD.

Cannabinoid Receptors and the Endocannabinoid System: Signaling and Function in the Central Nervous System

The biological effects of cannabinoids, the major constituents of the ancient medicinal plant Cannabis sativa (marijuana) are mediated by two members of the G-protein coupled receptor family, cannabinoid receptors 1 (CB1R) and 2. The CB1R is the prominent subtype in the central nervous system (CNS) and has drawn great attention as a potential therapeutic avenue in several pathological conditions, including neuropsychological disorders and neurodegenerative diseases. Furthermore, cannabinoids also modulate signal transduction pathways and exert profound effects at peripheral sites. Although cannabinoids have therapeutic potential, their psychoactive effects have largely limited their use in clinical practice. In this review, we briefly summarized our knowledge of cannabinoids and the endocannabinoid system, focusing on the CB1R and the CNS, with emphasis on recent breakthroughs in the field. We aim to define several potential roles of cannabinoid receptors in the modulation of signaling pathways and in association with several pathophysiological conditions. We believe that the therapeutic significance of cannabinoids is masked by the adverse effects and here alternative strategies are discussed to take therapeutic advantage of cannabinoids.

Novel derivatives of 1,2,3-triazole, cannabinoid-1 receptor ligands modulate gastrointestinal motility in mice

Cannabinoid-1 (CB1) receptors are broadly distributed in the central and peripheral nervous systems; among others, they are located in the enteric nervous system. In the gastrointestinal (GI) system, they participate in regulation of intestinal motility or ion transport. The aim of our study was to assess the effect of 1,2,3-triazole derivatives (compound 1: 2-[4,5-bis(2,4-dichlorophenyl)-2H-1,2,3-triazol-2-yl]-N-(2-fluorobenzyl)acetamide, compound 2: 2-[4,5-bis(2,4-dichlorophenyl)-2H-1,2,3-triazol-2-yl]-N-(4-fluorobenzyl)acetamide, compound 3: N-benzyl-2-[4-(4-chlorophenyl)-5-(2,4-dichlorophenyl)-2H-1,2,3-triazol-2-yl]acetamide]), characterized in vitro as CB1 antagonists with high CB1 over CB2 selectivity, in the mouse GI tract. The action of compounds 1-3 was assessed in vitro (electrical field stimulated smooth muscle contractility of the mouse ileum and colon) and in vivo (whole GI transit time). Compound 1 decreased ileal (10^-6 M) and colonic (10^-7-10^-6 M) smooth muscles contractility. Moreover, it prolonged whole GI transit. Compound 2 (10^-10-10^-8 M) slightly increased the amplitude of muscle contractions in the ileum, but at a higher concentration (10^-6 M), the amplitude was decreased. Compound 2 reduced colonic contractility but accelerated GI transit. Compound 3 decreased the amplitude of intestinal muscle contractions in the ileum (10^-6 M) and colon (10^-10-10^-6 M). Moreover, it increased the GI transit time in vivo. Triazole derivatives possess easily modifiable structure and interesting pharmacological action in the GI tract; further, alterations may enhance their efficacy at CB receptors and provide low side effect profile in clinical conditions.

Rimonabant Kills Colon Cancer Stem Cells without Inducing Toxicity in Normal Colon Organoids

Colorectal cancer (CRC), like other tumor types, is a highly heterogeneous disease. Within the tumor bulk, intra-tumoral heterogeneity is also ascribable to Cancer Stem Cells (CSCs) subpopulation, characterized by high chemoresistance and the unique ability to retain tumorigenic potential, thus associated to tumor recurrence. High dynamic plasticity of CSCs, makes the development of winning therapeutic strategies even more complex to completely eradicate tumor fuel. Rimonabant, originally synthesized as antagonist/inverse agonist of Cannabinoid Receptor 1, is able to inactivate Wnt signaling, both in vitro and in vivo, in CRC models, through inhibition of p300-histone acetyltransferase activity. Since Wnt/β-Catenin pathway is the main player underlying CSCs dynamic, this finding candidates Rimonabant as potential modulator of cancer stemness, in CRC. In this work, using established 3D cultures of primary colon CSCs, taking into account the tumor heterogeneity through monitoring of Wnt activity, we demonstrated that Rimonabant was able to reduces both tumor differentiated cells and colon CSCs proliferation and to control their survival in long term cultures. Interestingly, in ex vivo model of wild type human organoids, retaining both architecture and heterogeneity of original tissue, Rimonabant showed no toxicity against cells from healthy colon epithelium, suggesting its potential selectivity toward cancer cells. Overall, results from this work provided new insights on anti-tumor efficacy of Rimonabant, strongly suggesting that it could be a novel lead compound for CRC treatment.

Successful Treatment of Cannabinoid Hyperemesis Syndrome with Topical Capsaicin

Cannabinoid hyperemesis syndrome (CHS) is a clinical entity in which marijuana users develop nausea, vomiting, and abdominal pain that improves with hot water bathing or cannabis cessation. Previous models suggest that CHS arises solely from the derangement of cannabinoid receptor type 1 signaling. However, involvement of transient receptor potential vanilloid subtype 1 (TRPV1) receptor, which is activated by marijuana, capsaicin, and heat, could fill gaps in existing models, including the enigmatic role of hot water bathing. We propose that chronic cannabis use decreases TRPV1 signaling and alters gastric motility, and we report the case of a CHS patient whose symptoms improved after topical capsaicin.

Pathophysiological Mechanisms of Gastrointestinal Toxicity

Humans swallow a great variety and often large amounts of chemicals as nutrients, incidental food additives and contaminants, drugs, and inhaled particles and chemicals, thus exposing the gastrointestinal tract to many potentially toxic substances. It serves as a barrier in many cases to protect other components of the body from such substances and infections. Fortunately, the gastrointestinal tract is remarkably robust and generally is able to withstand multiple daily assaults by the chemicals to which it is exposed. Some chemicals, however, can affect one or more aspects of the gastrointestinal tract to produce abnormal events that reflect toxicity. It is the purpose of this chapter to evaluate the mechanisms by which toxic chemicals produce their deleterious effects and to determine the consequences of the toxicity on integrity of gastrointestinal structure and function. Probably because of the intrinsic ability of the gastrointestinal tract to resist toxic chemicals, there is a paucity of data regarding gastrointestinal toxicology. It is therefore necessary in many cases to extrapolate toxic mechanisms from infectious processes, inflammatory conditions, ischemia, and other insults in addition to more conventional chemical sources of toxicity.

Elevation of arachidonoylethanolamide levels by activation of the endocannabinoid system protects against colitis and ameliorates remote organ lesions in mice

The endocannabinoid system (ECS) is a potential pharmaceutical target for the treatment of inflammatory bowel diseases (IBDs). The aim of this study was to explore the effects of activation of the ECS on IBD and the associated neural inflammation-induced disruption of the blood-brain barrier (BBB). In a mouse model of trinitrobenzene sulfonic acid-induced colitis, the inhibition of fatty acid amide hydrolase with URB597 elevated the arachidonoylethanolamide concentration of the colon. Macroscopic alterations of the colons were evaluated, and the 7-day survival rate of mice was analyzed. BBB integrity was assessed using a dye tracer method, and the cognitive function of mice was examined using a fear-conditioning test. URB597 treatment significantly reduced macroscopic alterations of the colon, decreased the mortality rate, and protected the integrity of the BBB in the mice (P<0.05). No significant changes were observed in the cognitive functions of the mice (P>0.05); therefore, the neuroprotective effect of ECS in this colitis model requires further investigation. Activation of the ECS was efficient in ameliorating colitis and increasing the survival rate of the mice, and reducing remote organ changes induced by colitis. The results suggest that modulation of the ECS is a potential therapeutic approach for IBDs and the associated remote organ lesions.

Running Out of Options: Rhabdomyolysis Associated with Cannabis Hyperemesis Syndrome

Cannabis hyperemesis syndrome (CHS) is a condition in which some patients with long-term, frequent use of cannabis paradoxically develop recurrent episodes of nausea and vomiting. The pathophysiology underlying this condition is poorly understood, as is the explanation for its common association with patients' discovery that hot-water bathing alleviates symptoms. We describe the case of a 24-year-old male with daily marijuana use and a history of CHS who was found to have rhabdomyolysis induced by a period of 15 h of continuous jogging after he discovered that this activity helped to alleviate his symptoms. To our knowledge, this is the first reported case of exercise-alleviated CHS symptoms, and we propose that this case provides support to the theory of redistribution of enteric blood flow as the mechanism behind the learned hot-water bathing behavior seen so commonly in CHS.

Targeting fatty acid amide hydrolase and transient receptor potential vanilloid-1 simultaneously to modulate colonic motility and visceral sensation in the mouse: A pharmacological intervention with N-arachidonoyl-serotonin (AA-5-HT)

BACKGROUND

Endocannabinoid anandamide (AEA) inhibits intestinal motility and visceral pain, but it may also be proalgesic through transient receptor potential vanilloid-1 (TRPV1). AEA is degraded by fatty acid amide hydrolase (FAAH). This study explored whether dual inhibition of FAAH and TRPV1 reduces diarrhea and abdominal pain.

METHODS

Immunostaining was performed on myenteric plexus of the mouse colon. The effects of the dual FAAH/TRPV1 inhibitor AA-5-HT on electrically induced contractility, excitatory junction potential (EJP) and fast (f) and slow (s) inhibitory junction potentials (IJP) in the mouse colon, colonic propulsion and visceromotor response (VMR) to rectal distension were studied. The colonic levels of endocannabinoids and fatty acid amides were measured.

KEY RESULTS

CB1-positive neurons exhibited TRPV1; only some TRPV1 positive neurons did not express CB1. CB1 and FAAH did not colocalize. AA-5-HT (100 nM-10 μM) decreased colonic contractility by ~60%; this effect was abolished by TRPV1 antagonist 5'-IRTX, but not by CB1 antagonist, SR141716. AA-5-HT (1 μM-10 μM) inhibited EJP by ~30% and IJPs by ~50%. The effects of AA-5-HT on junction potentials were reversed by SR141716 and 5`-IRTX. AA-5-HT (20 mg/kg; i.p.) inhibited colonic propulsion by ~30%; SR141716 but not 5`-IRTX reversed this effect. AA-5-HT decreased VMR by ~50%-60%; these effects were not blocked by SR141716 or 5`-IRTX. AA-5-HT increased AEA in the colon.

CONCLUSIONS AND INFERENCES

The effects of AA-5-HT on visceral sensation and colonic motility are differentially mediated by CB1, TRPV1 and non-CB1/TRPV1 mechanisms, possibly reflecting the distinct neuromodulatory roles of endocannabinoid and endovanilloid FAAH substrates in the mouse intestine.

Complementary and Alternative Medicine Strategies for Therapeutic Gut Microbiota Modulation in Inflammatory Bowel Disease and their Next-Generation Approaches

The human gut microbiome exerts a major impact on human health and disease, and therapeutic gut microbiota modulation is now a well-advocated strategy in the management of many diseases, including inflammatory bowel disease (IBD). Scientific and clinical evidence in support of complementary and alternative medicine, in targeting intestinal dysbiosis among patients with IBD, or other disorders, has increased dramatically over the past years. Delivery of "artificial" stool replacements for fecal microbiota transplantation (FMT) could provide an effective, safer alternative to that of human donor stool. Nevertheless, optimum timing of FMT administration in IBD remains unexplored, and future investigations are essential.

Cannabis intake and intussusception: an accidental association?

Most intussusception cases in adults have an organic cause and their treatment is surgical. In some cases, there is no injury associated with intussusception and we can opt for conservative management. In our clinical practice we have shown the presence of intussusceptions in the absence of structural damage associated with chronic cannabis with a good course after conservative management. We describe three cases of recurrent intussusception in cannabis users, suggesting a relationship between cannabis use and the incidence of intussusception.

Endocannabinoid-related compounds in gastrointestinal diseases

The endocannabinoid system (ECS) is an endogenous signalling pathway involved in the control of several gastrointestinal (GI) functions at both peripheral and central levels. In recent years, it has become apparent that the ECS is pivotal in the regulation of GI motility, secretion and sensitivity, but endocannabinoids (ECs) are also involved in the regulation of intestinal inflammation and mucosal barrier permeability, suggesting their role in the pathophysiology of both functional and organic GI disorders. Genetic studies in patients with irritable bowel syndrome (IBS) or inflammatory bowel disease have indeed shown significant associations with polymorphisms or mutation in genes encoding for cannabinoid receptor or enzyme responsible for their catabolism, respectively. Furthermore, ongoing clinical trials are testing EC agonists/antagonists in the achievement of symptomatic relief from a number of GI symptoms. Despite this evidence, there is a lack of supportive RCTs and relevant data in human beings, and hence, the possible therapeutic application of these compounds is raising ethical, political and economic concerns. More recently, the identification of several EC-like compounds able to modulate ECS function without the typical central side effects of cannabino-mimetics has paved the way for emerging peripherally acting drugs. This review summarizes the possible mechanisms linking the ECS to GI disorders and describes the most recent advances in the manipulation of the ECS in the treatment of GI diseases.

The CB1 Receptor as the Cornerstone of Exostasis

The type-1 cannabinoid receptor (CB1) is the main effector of the endocannabinoid system (ECS), which is involved in most brain and body functions. In this Perspective, we provide evidence indicating that CB1 receptor functions are key determinants of bodily coordinated exostatic processes. First, we will introduce the concepts of endostasis and exostasis as compensation or accumulation for immediate or future energy needs and discuss how exostasis has been necessary for the survival of species during evolution. Then, we will argue how different specific biological functions of the CB1 receptor in the body converge to provide physiological exostatic processes. Finally, we will introduce the concept of proactive evolution-induced diseases (PEIDs), which helps explain the seeming paradox that an evolutionary-selected physiological function can become the cause of epidemic pathological conditions, such as obesity. We propose here a possible unifying theory of CB1 receptor functions that can be tested by future experimental studies.

G protein-coupled receptor GPR55 promotes colorectal cancer and has opposing effects to cannabinoid receptor 1

The putative cannabinoid receptor GPR55 has been shown to play a tumor-promoting role in various cancers, and is involved in many physiological and pathological processes of the gastrointestinal (GI) tract. While the cannabinoid receptor 1 (CB₁ ) has been reported to suppress intestinal tumor growth, the role of GPR55 in the development of GI cancers is unclear. We, therefore, aimed at elucidating the role of GPR55 in colorectal cancer (CRC), the third most common cancer worldwide. Using azoxymethane (AOM)- and dextran sulfate sodium (DSS)-driven CRC mouse models, we found that GPR55 plays a tumor-promoting role that involves alterations of leukocyte populations, i.e. myeloid-derived suppressor cells and T lymphocytes, within the tumor tissues. Concomitantly, expression levels of COX-2 and STAT3 were reduced in tumor tissue of GPR55 knockout mice, indicating reduced presence of tumor-promoting factors. By employing the experimental CRC models to CB₁ knockout and CB₁ /GPR55 double knockout mice, we can further show that GPR55 plays an opposing role to CB₁ . We report that GPR55 and CB₁ mRNA expression are differentially regulated in the experimental models and in a cohort of 86 CRC patients. Epigenetic methylation of CNR1 and GPR55 was also differentially regulated in human CRC tissue compared to control samples. Collectively, our data suggest that GPR55 and CB₁ play differential roles in colon carcinogenesis where the former seems to act as oncogene and the latter as tumor suppressor.

A case of cannabinoid hyperemesis syndrome with Heliobacter pylori and preeclampsia during pregnancy

BACKGROUND

The condition termed cannabinoid hyperemesis syndrome (CHS) was characterized a decade ago by Allen et al. and includes cyclic episodes of nausea and vomiting and the learned behavior of hot bathing in individuals with chronic cannabis abuse. During pregnancy, the differential diagnosis of this syndrome is challenging, since it can be masked by typical symptoms of early pregnancy or by hyperemesis gravidarum, a complication of early pregnancy associated with excessive nausea and vomiting.

CASE DESCRIPTION

The authors herein describe the case of a 21-year-old primigravida patient diagnosed with hyperemesis gravidarum at 6 weeks of gestation and with preeclampsia at 35 weeks. At 30 weeks of gestation, a drug screen was performed that was positive for cannabis; therefore, a diagnosis of CHS was made. After labor induction, the patient delivered an infant who developed normally and had a negative drug test of the umbilical cord blood. Esophagogastroduodenoscopy was performed 9 days post delivery, with biopsies taken of the duodenal, gastric, and esophageal tissues. Moderate chronic gastritis with lymphoid aggregates and slight acute inflammation were noticed, whereas no malignancy, dysplasia, or goblet cell metaplasia was detected. A number of Helicobacter-like organisms were identified by H. pylori immunostaining.

CONCLUSION

Presented here is the first case reporting an association of chronic cannabis use with H. pylori colonization and preeclampsia in pregnancy, which brings to light the possible involvement of a cannabinoid-related pathway in the link between pregnancy-specific complications and bacterial colonization.

Cannabinoid Receptor 1 Gene by Cannabis Use Interaction on CB1 Receptor Density

Background: Because delta-9-tetrahydrocannabinol (THC), the primary psychoactive ingredient in cannabis, binds to cannabinoid 1 (CB1) receptors, levels of CB1 protein could serve as a potential biomarker for response to THC. To date, available techniques to characterize CB1 expression and function in vivo are limited. In this study, we developed an assay to quantify CB1 in lymphocytes to determine how it relates to cannabis use in 58 daily cannabis users compared with 47 nonusers. Furthermore, we tested whether CB1 levels are associated with mutations in a single nucleotide polymorphism known to regulate CB1 functioning (i.e., rs2023239).

Methods: Total protein concentration was analyzed through the Pierce BCA Protein assay kit. CB1 protein was quantified through CNR1 enzyme-linked immunosorbent assay (ELISA) kit from MyBioSource. CB1 concentration and total protein concentration were quantified and used to calculate a ratio of CB1 to total protein.

Results: Inherent levels of peripheral lymphocyte CB1 were sufficient for quantification through ELISA without protein amplification. We found a group×genotype interaction such that users with the G allele had greater CB1 concentration than users with the A/A genotype, and a trend-level difference between genotypes in nonusers.

Conclusions: This study demonstrates a minimally invasive technique of CB1 quantification that holds promise for the use of CB1 protein concentration, along with rs2023239 genotype, as a potential biomarker for susceptibility to cannabis use. These results suggest a gene (rs2023239 G)×environment (cannabis use) effect on CB1 density.