Cannabinoids As Potential Treatment for Chemotherapy-Induced Nausea and Vomiting

A Comprehensive Review and Update on Cannabis Hyperemesis Syndrome

Cannabis, derived from Cannabis sativa plants, is a prevalent illicit substance in the United States, containing over 400 chemicals, including 100 cannabinoids, each affecting the body's organs differently upon ingestion. Cannabis hyperemesis syndrome (CHS) is a gut-brain axis disorder characterized by recurring nausea and vomiting intensified by excessive cannabis consumption. CHS often goes undiagnosed due to inconsistent criteria, subjective symptoms, and similarity to cyclical vomiting syndrome (CVS). Understanding the endocannabinoid system (ECS) and its dual response (pro-emetic at higher doses and anti-emetic at lower doses) is crucial in the pathophysiology of CHS. Recent research noted that type 1 cannabinoid receptors in the intestinal nerve plexus exhibit an inhibitory effect on gastrointestinal motility. At the same time, the thermoregulatory function of endocannabinoids might explain compulsive hot bathing in CHS patients. The prevalence of cannabis CHS is expected to rise as legal restrictions on its recreational use decrease in several states. Education and awareness are vital in diagnosing and treating CHS as its prevalence increases. This comprehensive review explores the ECS's involvement, CHS management approaches, and knowledge gaps to enhance understanding of this syndrome.

A head-to-head comparison of MM/PBSA and MM/GBSA in predicting binding affinities for the CB1 cannabinoid ligands

CONTEXT

The substantial increase in the number of active and inactive-state CB1 receptor experimental structures has provided opportunities for CB1 drug discovery using various structure-based drug design methods, including the popular end-point methods for predicting binding free energies-Molecular Mechanics/Poisson-Boltzmann Surface Area (MM/PBSA) and Molecular Mechanics/Generalized Born Surface Area (MM/GBSA). In this study, we have therefore evaluated the performance of MM/PBSA and MM/GBSA in calculating binding free energies for CB1 receptor. Additionally, with both MM/PBSA and MM/GBSA being known for their highly individualized performance, we have evaluated the effects of various simulation parameters including the use of energy minimized structures, choice of solute dielectric constant, inclusion of entropy, and the effects of the five GB models. Generally, MM/GBSA provided higher correlations than MM/PBSA (rMM/GBSA = 0.433 - 0.652 vs. rMM/PBSA = 0.100 - 0.486) regardless of the simulation parameters, while also offering faster calculations. Improved correlations were observed with the use of molecular dynamics ensembles compared with energy minimized structures and larger solute dielectric constants. Incorporation of entropic terms led to unfavorable results for both MM/PBSA and MM/GBSA for a majority of the dataset, while the evaluation of the various GB models exerted a varying effect on both the datasets. The findings obtained in this study demonstrate the utility of MM/PBSA and MM/GBSA in predicting binding free energies for the CB1 receptor, hence providing a useful benchmark for their applicability in the endocannabinoid system as well as other G protein-coupled receptors.

METHODS

The study utilized the docked dataset (Induced Fit Docking with Glide XP scoring function) from Loo et al., consisting of 46 ligands-23 agonists and 23 antagonists. The equilibrated structures from Loo et al. were subjected to 30 ns production simulations using GROMACS 2018 at 300 K and 1 atm with the velocity rescaling thermostat and the Parinello-Rahman barostat. AMBER ff99SB*-ILDN was used for the proteins, General Amber Force Field (GAFF) was used for the ligands, and Slipids parameters were used for lipids. MM/PBSA and MM/GBSA binding free energies were then calculated using gmx_MMPBSA. The solute dielectric constant was varied between 1, 2, and 4 to study the effect of different solute dielectric constants on the performance of MM/PB(GB)SA. The effect of entropy on MM/PB(GB)SA binding free energies was evaluated using the interaction entropy module implemented in gmx_MMPBSA. Five GB models, GBHCT, GBOBC1, GBOBC2, GBNeck, and GBNeck2, were evaluated to study the effect of the choice of GB models in the performance of MM/GBSA. Pearson correlation coefficients were used to measure the correlation between experimental and predicted binding free energies.

Surgery-Related Considerations in Treating People Who Use Cannabis: A Review

Importance

Cannabis use has experienced substantial growth. Many patients treated by otolaryngologists are using cannabis in various forms, often without the knowledge of the treating surgeon. These cannabinoid substances have various systemic effects, and it is critical for otolaryngologists to recognize how cannabis use may contribute to a patient's care.

Observations

Cannabis use has effects that contribute to every phase of a surgeon's care. Preoperative counseling for tapering use may prevent increased rates of adverse effects. Care with anesthesia must be observed due to increased rates of myocardial ischemia, higher tolerance to standard doses, and prolonged sedation. Although results of studies are mixed, there may be an association with cannabis use and postoperative pain, nausea, and vomiting. Postoperative wound healing may be improved through the use of topical cannabinoids. Significant drug-drug interactions exist with cannabis, most notably with several common anticoagulant medications. Care should be exercised when managing medications for people who use cannabis. While many people who use cannabis consume it infrequently, a substantial population has developed cannabis use disorder, which is associated with increased morbidity and mortality postoperatively. Screening for cannabis use disorder is important and can be done through short screening tools.

Conclusions and Relevance

Patients who use cannabis may require special attention regarding preoperative counseling and workup, intraoperative anesthesia, postoperative pain management, nausea, wound healing, and drug-drug interactions. As patient use continues to increase, otolaryngologists will find an increasing need to remain up to date on how cannabis use contributes to patient care.

Large library docking for cannabinoid-1 receptor agonists with reduced side effects

Large library docking can reveal unexpected chemotypes that complement the structures of biological targets. Seeking new agonists for the cannabinoid-1 receptor (CB1R), we docked 74 million tangible molecules, prioritizing 46 high ranking ones for de novo synthesis and testing. Nine were active by radioligand competition, a 20% hit-rate. Structure-based optimization of one of the most potent of these (Ki = 0.7 uM) led to '4042, a 1.9 nM ligand and a full CB1R agonist. A cryo-EM structure of the purified enantiomer of '4042 ('1350) in complex with CB1R-Gi1 confirmed its docked pose. The new agonist was strongly analgesic, with generally a 5-10-fold therapeutic window over sedation and catalepsy and no observable conditioned place preference. These findings suggest that new cannabinoid chemotypes may disentangle characteristic cannabinoid side-effects from their analgesia, supporting the further development of cannabinoids as pain therapeutics.

Synthesis and Evaluation of Natural and Unnatural Tetrahydrocannabiorcol for Its Potential Use in Neuropathologies

(-)-trans-Δ9-Tetrahydrocannabinol (trans-(-)-Δ9-THC) has shown neuroprotective potential, but its medicinal benefits are not fully exploited due to the limitations of psychoactive properties. The lower homologues are non-psychoactive in nature but lack comprehensive scientific validation regarding neuroprotective potential. The present study describes the synthesis of non-psychoactive lower homologues of THC-type compounds and their neuroprotective potential. Both natural tetrahydro-cannabiorcol (trans-(-)-Δ9-THCO) and unnatural Δ9-tetrahydrocannabiorcol (trans-(+)-Δ9-THCO) were successfully synthesized starting from R-limonene and S-limonene, respectively, and investigated for neuroprotective potential in cellular models. The structures of both enantiomers were confirmed by NMR, HMBC, HQSC, NOESY, and COSY experiments. Results indicated that both enantiomers were nontoxic to the cells treated up to 50 μM. Neuroprotective properties of the enantiomers showed that treatments could significantly reverse the corticosterone-induced toxicity in SH-SY5Y cells and simultaneously cause elevated expression of brain-derived neurotrophic factor (BDNF). It was also observed that unnatural trans-(+)-Δ9-THCO displayed better activity than the natural enantiomer and can be further explored for its potential use in neuropathological ailments.

Plasma endocannabinoids and cannabimimetic fatty acid derivatives are altered in cyclic vomiting syndrome: The effects of sham feeding

Cyclic vomiting syndrome (CVS) is an underdiagnosed disorder of the gut-brain interaction. Our understanding of the pathophysiology of CVS is evolving. Here, we tested the hypotheses that: (1) the levels of endocannabinoids and related lipids are altered in CVS, and (2) cephalic-vagal stimulation drive changes in endolipid levels. Ten adult patients with CVS and eight healthy controls were included. Indirect measurements of parasympathetic (RFa) functions were performed with spectral analysis of heart rate variability and respiratory activity. Plasma levels of endocannabinoids and related lipids were measured at baseline and during a sham feeding. Values are reported as mean ± standard error of the mean and compared using t-test or ANOVA. CVS patients had a lower parasympathetic tone and response to the Valsalva maneuver and deep breathing than the controls. The baseline 2-Arachidonoylglycerol (2-AG) had a significantly higher concentration in CVS (5.9e-008 ± 3.7e-008 mol/L) than control (3.7e-008 ± 1.3e-008 mol/; p < 0.05). Sham feeding did not change the concentration of 2-AG. 2-oleoylglycerol (2-OG) was significantly higher in CVS than control and did not change with sham feeding. Levels of N-acylethanolamines, including anandamide (AEA), were not different in CVS vs control. After sham feeding, AEA showed a trend toward increasing (p = 0.08) in CVS, but not in control. With sham feeding, palmitoyl ethanolamine significantly increased in both CVS and control groups; oleoyl ethanolamine in CVS only, and stearoyl ethanolamine in the control group. Levels of endocannabinoids and related lipids are altered in CVS patients. Sham feeding affects endogenous signaling lipids in a disease and time-dependent manner.

Phytocannabinoids Reduce Seizures in Larval Zebrafish and Affect Endocannabinoid Gene Expression

Cannabis has demonstrated anticonvulsant properties, and about thirty percent of epileptic patients do not have satisfactory seizure management with standard treatment and could potentially benefit from cannabis-based intervention. Here, we report the use of cannabinoids to treat pentylenetetrazol (PTZ)-induced convulsions in a zebrafish model, their effect on gene expression, and a simple assay for assessing their uptake in zebrafish tissues. Using an optimized behavioral assay, we show that cannabidiol (CBD) and cannabichromene (CBC) and cannabinol (CBN) are effective at reducing seizures at low doses, with little evidence of sedation, and our novel HPLC assay indicates that CBC is effective with the lowest accumulation in larval tissues. All cannabinoids tested were effective at higher concentrations. Pharmacological manipulation of potential receptors demonstrates that Gpr55 partially mediates the anticonvulsant effects of CBD. Treatment of zebrafish larvae with endocannabinoids, such as 2-arachidonoylglycerol (2-AG) and anandamide (AEA), altered larvae movement, and the expression of genes that regulate their metabolism was affected by phytocannabinoid treatment, highlighting the possibility that changes to endocannabinoid levels may represent one facet of the anticonvulsant effect of phytocannabinoids.

Endocannabinoid System and Exogenous Cannabinoids in Depression and Anxiety: A Review

Background: There is a growing liberalization of cannabis-based preparations for medical and recreational use. In multiple instances, anxiety and depression are cited as either a primary or a secondary reason for the use of cannabinoids. Aim: The purpose of this review is to explore the association between depression or anxiety and the dysregulation of the endogenous endocannabinoid system (ECS), as well as the use of phytocannabinoids and synthetic cannabinoids in the remediation of depression/anxiety symptoms. After a brief description of the constituents of cannabis, cannabinoid receptors and the endocannabinoid system, the most important evidence is presented for the involvement of cannabinoids in depression and anxiety both in human and from animal models of depression and anxiety. Finally, evidence is presented for the clinical use of cannabinoids to treat depression and anxiety. Conclusions: Although the common belief that cannabinoids, including cannabis, its main studied components-tetrahydrocannabinol (THC) and cannabidiol (CBD)-or other synthetic derivatives have been suggested to have a therapeutic role for certain mental health conditions, all recent systematic reviews that we report have concluded that the evidence that cannabinoids improve depressive and anxiety disorders is weak, of very-low-quality, and offers no guidance on the use of cannabinoids for mental health conditions within a regulatory framework. There is an urgent need for high-quality studies examining the effects of cannabinoids on mental disorders in general and depression/anxiety in particular, as well as the consequences of long-term use of these preparations due to possible risks such as addiction and even reversal of improvement.

Cannabinoid drugs against chemotherapy-induced adverse effects: focus on nausea/vomiting, peripheral neuropathy and chemofog in animal models

Although new drugs are being developed for cancer treatment, classical chemotherapeutic agents are still front-line therapies, despite their frequent association with severe side effects that can hamper their use. Cannabinoids may prevent or palliate some of these side effects. The aim of the present study is to review the basic research which has been conducted evaluating the effects of cannabinoid drugs in the treatment of three important side effects induced by classical chemotherapeutic agents: nausea and vomiting, neuropathic pain and cognitive impairment. Several published studies have demonstrated that cannabinoids are useful in preventing and reducing the nausea, vomits and neuropathy induced by different chemotherapy regimens, though other side effects can occur, such as a reduction of gastrointestinal motility, along with psychotropic effects when using centrally-acting cannabinoids. Thus, peripherally-acting cannabinoids and new pharmacological options are being investigated, such as allosteric or biased agonists. Additionally, due to the increase in the survival of cancer patients, there are emerging data that demonstrate an important cognitive deterioration due to chemotherapy, and because the cannabinoid drugs have a neuroprotective effect, they could be useful in preventing chemotherapy-induced cognitive impairment (as demonstrated through studies in other neurological disorders), but this has not yet been tested. Thus, although cannabinoids seem a promising therapeutic approach in the treatment of different side effects induced by chemotherapeutic agents, future research will be necessary to find pharmacological options with a safer profile. Moreover, a new line of research awaits to be opened to elucidate their possible usefulness in preventing cognitive impairment.

Cannabinoids and Cancer Chemotherapy-Associated Adverse Effects

The use of cannabis is not unfamiliar to many cancer patients, as there is a long history of its use for cancer pain and/or pain, nausea, and cachexia induced by cancer treatment. To date, the US Food and Drug Administration has approved 2 cannabis-based pharmacotherapies for the treatment of cancer chemotherapy-associated adverse effects: dronabinol and nabilone. Over the proceeding decades, both research investigating and societal attitudes toward the potential utility of cannabinoids for a range of indications have progressed dramatically. The following monograph highlights recent preclinical research focusing on promising cannabinoid-based approaches for the treatment of the 2 most common adverse effects of cancer chemotherapy: chemotherapy-induced peripheral neuropathy and chemotherapy-induced nausea and vomiting. Both plant-derived and synthetic approaches are discussed, as is the potential relative safety and effectiveness of these approaches in relation to current treatment options, including opioid analgesics.

Mechanisms of Nausea and Vomiting: Current Knowledge and Recent Advances in Intracellular Emetic Signaling Systems

Nausea and vomiting are common gastrointestinal complaints that can be triggered by diverse emetic stimuli through central and/or peripheral nervous systems. Both nausea and vomiting are considered as defense mechanisms when threatening toxins/drugs/bacteria/viruses/fungi enter the body either via the enteral (e.g., the gastrointestinal tract) or parenteral routes, including the blood, skin, and respiratory systems. While vomiting is the act of forceful removal of gastrointestinal contents, nausea is believed to be a subjective sensation that is more difficult to study in nonhuman species. In this review, the authors discuss the anatomical structures, neurotransmitters/mediators, and corresponding receptors, as well as intracellular emetic signaling pathways involved in the processes of nausea and vomiting in diverse animal models as well as humans. While blockade of emetic receptors in the prevention of vomiting is fairly well understood, the potential of new classes of antiemetics altering postreceptor signal transduction mechanisms is currently evolving, which is also reviewed. Finally, future directions within the field will be discussed in terms of important questions that remain to be resolved and advances in technology that may help provide potential answers.

Cannabis hyperemesis syndrome: an update on the pathophysiology and management

Cannabis hyperemesis syndrome (CHS) is a form of functional gut-brain axis disorder characterized by bouts of episodic nausea and vomiting worsened by cannabis intake. It is considered as a variant of cyclical vomiting syndrome seen in cannabis users especially characterized by compulsive hot bathing/showers to relieve the symptoms. CHS was reported for the first time in 2004, and since then, an increasing number of cases have been reported. With cannabis use increasing throughout the world as the threshold for legalization becomes lower, its user numbers are expected to rise over time. Despite this trend, a strict criterion for the diagnosis of CHS is lacking. Early recognition of CHS is essential to prevent complications related to severe volume depletion. The recent body of research recognizes that patients with CHS impose a burden on the healthcare systems. Understanding the pathophysiology of the endocannabinoid system (ECS) remains central in explaining the clinical features and potential drug targets for the treatment of CHS. The frequency and prevalence of CHS change in accordance with the doses of tetrahydrocannabinol and other cannabinoids in various formulations of cannabis. CHS is unique in presentation, because of the cannabis’s biphasic effect as anti-emetic at low doses and pro-emetic at higher doses, and the association with pathological hot water bathing. In this narrative review, we elaborate on the role of the ECS, its management, and the identification of gaps in our current knowledge of CHS to further enhance its understanding in the future.

Pharmacokinetic and Safety Evaluation of Various Oral Doses of a Novel 1:20 THC:CBD Cannabis Herbal Extract in Dogs

Objective: To determine the pharmacokinetics (PK) and safety of various oral doses of a Cannabis herbal extract (CHE) containing a 1:20 ratio of Δ9-tetrahydrocannabinol (THC):cannabidiol (CBD) in 13 healthy Beagle-cross dogs.

Methods: Single-dose PK was assessed after oral administration of CHE at low, medium, or high doses [2, 5, or 10 mg CBD and 0.1, 0.25, or 0.5 mg THC per kg of body weight (bw), respectively; n = 6 per group]. Dogs were monitored for adverse events for up to 48 h post-dose. Evaluations of neurological signs, clinical laboratory abnormalities, and other adverse events were performed in two separate study phases: a multiple-dose phase with 12 dogs receiving five medium doses (5 mg CBD/kg bw) at 12 h intervals, and a single low-dose (2 mg CBD/kg bw), randomized, blinded, negative controlled study with 13 dogs.

Results: Cannabinoids CBD, THC, CBC, and metabolites 6-OH-CBD, 7-OH-CBD, 11-OH-THC, and THC-COOH were quantified in plasma. CBD and THC were rapidly absorbed (mean T_max of 1.9–2.3 h) and initially depleted rapidly (mean CBD T_1/2β of 2.3–2.6 h). A prolonged elimination phase (mean CBD T_1/2λ of 13.3–24.4 h) was observed. CBD and THC concentrations increased in a dose-dependent (non-linear) manner, with disproportionally greater cannabinoid exposure relative to the dose increase. Neurological signs (hyperesthesia or proprioceptive deficits) were noted in five of six dogs in the high-dose group, but only occasionally or rarely in the medium- and low-dose groups, respectively. Presence and severity of clinical signs correlated with plasma cannabinoid concentrations. Dogs appeared to develop a tolerance to cannabinoid effects after multiple CHE doses, with fewer neurological signs noted after the final (fifth) vs. first dose. No clinically meaningful changes in blood count or chemistry values occurred after multiple CHE doses.

Clinical Significance: Dogs tolerated the 1:20 THC:CBD formulation well at low and medium doses, but clinically meaningful neurological signs were observed at high doses. Because of non-proportional increases in plasma cannabinoid concentrations with increasing doses, as well as potential differences in CHE product composition and bioavailability, the possibility of adverse events and dose regimen consistency should be discussed with dog owners.

It Is Our Turn to Get Cannabis High: Put Cannabinoids in Food and Health Baskets

Cannabis is an annual plant with a long history of use as food, feed, fiber, oil, medicine, and narcotics. Despite realizing its true value, it has not yet found its true place. Cannabis has had a long history with many ups and downs, and now it is our turn to promote it. Cannabis contains approximately 600 identified and many yet unidentified potentially useful compounds. Cannabinoids, phenolic compounds, terpenoids, and alkaloids are some of the secondary metabolites present in cannabis. However, among a plethora of unique chemical compounds found in this plant, the most important ones are phytocannabinoids (PCs). Over hundreds of 21-22-carbon compounds exclusively produce in cannabis glandular hairs through either polyketide and or deoxyxylulose phosphate/methylerythritol phosphate (DOXP/MEP) pathways. Trans-Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD) are those that first come to mind while talking about cannabis. Nevertheless, despite the low concentration, cannabinol (CBN), cannabigerol (CBG), cannabichromene (CBC), tetrahydrocannabivarin (THCV), cannabidivarin (CBDV), cannabinodiol (CBND), and cannabinidiol (CBDL) may have potentially some medical effects. PCs and endocannabinoids (ECs) mediate their effects mainly through CB1 and CB2 receptors. Despite all concerns regarding cannabis, nobody can ignore the use of cannabinoids as promising tonic, analgesic, antipyretic, antiemetic, anti-inflammatory, anti-epileptic, anticancer agents, which are effective for pain relief, depression, anxiety, sleep disorders, nausea and vomiting, multiple sclerosis, cardiovascular disorders, and appetite stimulation. The scientific community and public society have now increasingly accepted cannabis specifically hemp as much more than a recreational drug. There are growing demands for cannabinoids, mainly CBD, with many diverse therapeutic and nutritional properties in veterinary or human medicine. The main objective of this review article is to historically summarize findings concerning cannabinoids, mainly THC and CBD, towards putting these valuable compounds into food, feed and health baskets and current and future trends in the consumption of products derived from cannabis.

Evaluation of repeated or acute treatment with cannabidiol (CBD), cannabidiolic acid (CBDA) or CBDA methyl ester (HU-580) on nausea and/or vomiting in rats and shrews

RATIONALE

When acutely administered intraperitoneally, the non-psychoactive cannabinoid cannabidiol (CBD), its acidic precursor cannabidiolic acid (CBDA) and a stable methyl ester of CBDA (HU-580) reduce lithium chloride (LiCl)-induced conditioned gaping in male rats (a selective preclinical model of acute nausea) via activation of the serotonin 1A (5-HT_1A) receptor.

OBJECTIVES

To utilise these compounds to manage nausea in the clinic, we must determine if their effectiveness is maintained when injected subcutaneously (s.c) and when repeatedly administered. First, we compared the effectiveness of each of these compounds to reduce conditioned gaping following repeated (7-day) and acute (1-day) pretreatments and whether these anti-nausea effects were mediated by the 5-HT_1A receptor. Next, we assessed whether the effectiveness of these compounds can be maintained when administered prior to each of 4 conditioning trials (once per week). We also evaluated the ability of repeated CBD (7 days) to reduce LiCl-induced vomiting in Suncus murinus. Finally, we examined whether acute CBD was equally effective in male and female rats.

RESULTS

Both acute and repeated (7 day) s.c. administrations of CBD (5 mg/kg), CBDA (1 μg/kg) and HU-580 (1 μg/kg) similarly reduced LiCl-induced conditioned gaping, and these effects were blocked by 5HT_1A receptor antagonism. When administered over 4 weekly conditioning trials, the anti-nausea effectiveness of each of these compounds was also maintained. Repeated CBD (5 mg/kg, s.c.) maintained its anti-emetic efficacy in S. murinus. Acute CBD (5 and 20 mg/kg, s.c.) administration reduced LiCl-induced conditioned gaping similarly in male and female rats.

CONCLUSION

When administered repeatedly (7 days), CBD, CBDA and HU-580 did not lose efficacy in reducing nausea and continued to act via agonism of the 5-HT_1A receptor. When administered across 4 weekly conditioning trials, they maintained their effectiveness in reducing LiCl-induced nausea. Repeated CBD also reduced vomiting in shrews. Finally, CBD's anti-nausea effects were similar in male and female rats. This suggests that these cannabinoids may be useful anti-nausea and anti-emetic treatments for chronic conditions, without the development of tolerance.

Targeting the endocannabinoid system: a predictive, preventive, and personalized medicine-directed approach to the management of brain pathologies

Cannabis-inspired medical products are garnering increasing attention from the scientific community, general public, and health policy makers. A plethora of scientific literature demonstrates intricate engagement of the endocannabinoid system with human immunology, psychology, developmental processes, neuronal plasticity, signal transduction, and metabolic regulation. Despite the therapeutic potential, the adverse psychoactive effects and historical stigma, cannabinoids have limited widespread clinical application. Therefore, it is plausible to weigh carefully the beneficial effects of cannabinoids against the potential adverse impacts for every individual. This is where the concept of "personalized medicine" as a promising approach for disease prediction and prevention may take into the account. The goal of this review is to provide an outline of the endocannabinoid system, including endocannabinoid metabolizing pathways, and will progress to a more in-depth discussion of the therapeutic interventions by endocannabinoids in various neurological disorders.

Effect of combined doses of Δ9-tetrahydrocannabinol and cannabidiol or tetrahydrocannabinolic acid and cannabidiolic acid on acute nausea in male Sprague-Dawley rats

RATIONALE

This study evaluated the potential of combined cannabis constituents to reduce nausea.

OBJECTIVES

Using the lithium chloride (LiCl)-induced conditioned gaping model of nausea in male rats, we aimed to: 1) Determine effective anti-nausea doses of cannabidiol (CBD) 2) Determine effectiveness and the mechanism of action of combined subthreshold doses of CBD and Δ⁹-tetrahydrocannabinol (THC) 3) Determine effective doses of synthetic cannabidiolic acid (CBDA) 4) Determine effective doses of synthetic tetrahydrocannabinolic acid (THCA) 5) Determine the mechanism of action for THCA 6) Determine effectiveness and the mechanism of action of combined subthreshold doses of CBDA and THCA RESULTS: CBD (0.5-5 mg/kg, intraperitoneal [i.p.]) reduces LiCl-induced conditioned gaping (but 0.1, 20, 40 mg/kg are ineffective). Combined subthreshold doses of CBD (0.1 mg/kg, i.p.) and THC (0.1 mg/kg, i.p.) produce suppression of conditioned gaping, and this effect is blocked by administration of either WAY100635 (a serotonin 1A [5-HT_1A]) receptor antagonist or SR141716 (SR; a CB₁ receptor antagonist). THCA (0.01 mg/kg, i.p.) reduces conditioned gaping and administration of MK886 (a peroxisome proliferator-activated receptor alpha [PPARα] antagonist) blocked THCA's anti-nausea effect. Combined subthreshold doses of CBDA (0.00001 mg/kg, i.p.) and THCA (0.001 mg/kg, i.p.) produce suppression of conditioned gaping, and this effect is blocked by administration of WAY100635 or MK886.

CONCLUSION

Combinations of very low doses of CBD + THC or CBDA + THCA robustly reduce LiCl-induced conditioned gaping. Clinical trials are necessary to determine the efficacy of using single or combined cannabinoids as adjunct treatments with existing anti-emetic regimens to manage chemotherapy-induced nausea.

Altered SWD stopping mechanism in WAG/Rij rats subchronically treated with the cannabinoid agonist R(+)WIN55,212-2

A single injection of the cannabinoid agonist R(+)WIN55,212-2 (WIN) is known to cause an increase of the mean duration of spontaneously occurring spike-and-wave discharges (SWDs) in rats of the WAG/Rij strain, a genetic model for absence epilepsy. The aim of the present study was to establish whether repeated activation of CB₁ receptors with WIN leads to tolerance in its effect on SWD parameters, spectral density, and behavior over time. Adult male WAG/Rij rats (n = 16) were treated with WIN (6 mg/kg) or vehicle (olive oil). Injections (s.c.) took place 3 times per week during 2 weeks. Electroencephalogram (EEG) recordings, each lasting 24 h, were made 3 times: immediately before the first injection (baseline), immediately after the first injection (acute treatment), and after 2 weeks of treatment (subchronic treatment). The recordings were analyzed regarding incidence, durations of SWDs, and hazard rates of the durations of SWDs, the latter to describe SWD stopping probabilities. Putative changes in the spectral content of the EEG before and after WIN during active and passive behaviors were additionally investigated. Spike-and-wave discharge incidence was not affected by the acute and subchronic treatments. The mean duration of the SWDs was significantly longer than controls in the acute WIN-treated animals [11.9-s standard error of the mean (SEM): 0.64 compared with 8.4-s SEM: 0.25] as well as in subchronically treated animals (11.5-s SEM: 1.00 compared with 8.4-s SEM: 0.25). Hazard rates were significantly lower for WIN-treated animals at SWD durations in the 5.04-20.16-s range on both occasions. No effects of WIN on the frequency spectrum of the ongoing EEG were found, neither acutely nor after repeated administration. Evidence for tolerance was not found. The results on the mean duration and hazard rates suggest that stimulating the endocannabinoid system affects the SWD stopping mechanism, resulting in more long SWDs. We speculate that this effect is likely to be a direct result of CB₁ receptor agonism and a subsequent decrease in the availability of gamma-aminobutyric acid (GABA) in the reticular thalamic nucleus, which further weakens, in WAG/Rij rats already disturbed, the stopping mechanism of the SWDs.

From Cannabinoids and Neurosteroids to Statins and the Ketogenic Diet: New Therapeutic Avenues in Rett Syndrome?

Rett syndrome (RTT) is an X-linked neurodevelopmental disorder caused mainly by mutations in the MECP2 gene, being one of the leading causes of mental disability in females. Mutations in the MECP2 gene are responsible for 95% of the diagnosed RTT cases and the mechanisms through which these mutations relate with symptomatology are still elusive. Children with RTT present a period of apparent normal development followed by a rapid regression in speech and behavior and a progressive deterioration of motor abilities. Epilepsy is one of the most common symptoms in RTT, occurring in 60 to 80% of RTT cases, being associated with worsening of other symptoms. At this point, no cure for RTT is available and there is a pressing need for the discovery of new drug candidates to treat its severe symptoms. However, despite being a rare disease, in the last decade research in RTT has grown exponentially. New and exciting evidence has been gathered and the etiopathogenesis of this complex, severe and untreatable disease is slowly being unfolded. Advances in gene editing techniques have prompted cure-oriented research in RTT. Nonetheless, at this point, finding a cure is a distant reality, highlighting the importance of further investigating the basic pathological mechanisms of this disease. In this review, we focus our attention in some of the newest evidence on RTT clinical and preclinical research, evaluating their impact in RTT symptomatology control, and pinpointing possible directions for future research.

Cannabinoids: Current and Future Options to Treat Chronic and Chemotherapy-Induced Neuropathic Pain

Increases in cancer diagnosis have tremendous negative impacts on patients and their families, and major societal and economic costs. The beneficial effect of chemotherapeutic agents on tumor suppression comes with major unwanted side effects such as weight and hair loss, nausea and vomiting, and neuropathic pain. Chemotherapy-induced peripheral neuropathy (CIPN), which can include both painful and non-painful symptoms, can persist 6 months or longer after the patient's last chemotherapeutic treatment. These peripheral sensory and motor deficits are poorly treated by our current analgesics with limited effectiveness. Therefore, the development of novel treatment strategies is an important preclinical research focus and an urgent need for patients. Approaches to prevent CIPN have yielded disappointing results since these compounds may interfere with the anti-tumor properties of chemotherapeutic agents. Nevertheless, the first (serotonin noradrenaline reuptake inhibitors [SNRIs], anticonvulsants, tricyclic antidepressants) and second (5% lidocaine patches, 8% capsaicin patches and weak opioids such as tramadol) lines of treatment for CIPN have shown some efficacy. The clinical challenge of CIPN management in cancer patients and the need to target novel therapies with long-term efficacy in alleviating CIPN are an ongoing focus of research. The endogenous cannabinoid system has shown great promise and efficacy in alleviating CIPN in preclinical and clinical studies. In this review, we will discuss the mechanisms through which the platinum, taxane, and vinca alkaloid classes of chemotherapeutics may produce CIPN and the potential therapeutic effect of drugs targeting the endocannabinoid system in preclinical and clinical studies, in addition to cannabinoid compounds diffuse mechanisms of action in alleviation of CIPN.

A History of Drug Discovery for Treatment of Nausea and Vomiting and the Implications for Future Research

The origins of the major classes of current anti-emetics are examined. Serendipity is a recurrent theme in discovery of their anti-emetic properties and repurposing from one indication to another is a continuing trend. Notably, the discoveries have occurred against a background of company mergers and changing anti-emetic requirements. Major drug classes include: (i) Muscarinic receptor antagonists-originated from historical accounts of plant extracts containing atropine and hyoscine with development stimulated by the need to prevent sea-sickness among soldiers during beach landings; (ii) Histamine receptor antagonists-searching for replacements for the anti-malaria drug quinine, in short supply because of wartime shipping blockade, facilitated the discovery of histamine (H1) antagonists (e.g., dimenhydrinate), followed by serendipitous discovery of anti-emetic activity against motion sickness in a patient undergoing treatment for urticaria; (iii) Phenothiazines and dopamine receptor antagonists-investigations of their pharmacology as "sedatives" (e.g., chlorpromazine) implicated dopamine receptors in emesis, leading to development of selective dopamine (D2) receptor antagonists (e.g., domperidone with poor ability to penetrate the blood-brain barrier) as anti-emetics in chemotherapy and surgery; (iv) Metoclopramide and selective 5-hydroxytryptamine3(5-HT3) receptor antagonists-metoclopramide was initially assumed to act only via D2 receptor antagonism but subsequently its gastric motility stimulant effect (proposed to contribute to the anti-emetic action) was shown to be due to 5-hydroxytryptamine4 receptor agonism. Pre-clinical studies showed that anti-emetic efficacy against the newly-introduced, highly emetic, chemotherapeutic agent cisplatin was due to antagonism at 5-HT3 receptors. The latter led to identification of selective 5-HT3 receptor antagonists (e.g., granisetron), a major breakthrough in treatment of chemotherapy-induced emesis; (v) Neurokinin1receptor antagonists-antagonists of the actions of substance P were developed as analgesics but pre-clinical studies identified broad-spectrum anti-emetic effects; clinical studies showed particular efficacy in the delayed phase of chemotherapy-induced emesis. Finally, the repurposing of different drugs for treatment of nausea and vomiting is examined, particularly during palliative care, and also the challenges in identifying novel anti-emetic drugs, particularly for treatment of nausea as compared to vomiting. We consider the lessons from the past for the future and ask why there has not been a major breakthrough in the last 20 years.

The Endocannabinoid/Cannabinoid Receptor 2 System Protects Against Cisplatin-Induced Hearing Loss

Previous studies have demonstrated the presence of cannabinoid 2 receptor (CB2R) in the rat cochlea which was induced by cisplatin. In an organ of Corti-derived cell culture model, it was also shown that an agonist of the CB2R protected these cells against cisplatin-induced apoptosis. In the current study, we determined the distribution of CB2R in the mouse and rat cochleae and examined whether these receptors provide protection against cisplatin-induced hearing loss. In a knock-in mouse model expressing the CB2R tagged with green fluorescent protein, we show distribution of CB2R in the organ of Corti, stria vascularis, spiral ligament and spiral ganglion cells. A similar distribution of CB2R was observed in the rat cochlea using a polyclonal antibody against CB2R. Trans-tympanic administration of (2-methyl-1-propyl-1H-indol-3-yl)-1-naphthalenylmethanone (JWH015), a selective agonist of the CB2R, protected against cisplatin-induced hearing loss which was reversed by blockade of this receptor with 6-iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indol-3-yl](4-methoxyphenyl)methanone (AM630), an antagonist of CB2R. JWH015 also reduced the loss of outer hair cells (OHCs) in the organ of Corti, loss of inner hair cell (IHC) ribbon synapses and loss of Na⁺/K⁺-ATPase immunoreactivity in the stria vascularis. Administration of AM630 alone produced significant hearing loss (measured by auditory brainstem responses) which was not associated with loss of OHCs, but led to reductions in the levels of IHC ribbon synapses and strial Na⁺/K⁺-ATPase immunoreactivity. Furthermore, knock-down of CB2R by trans-tympanic administration of siRNA sensitized the cochlea to cisplatin-induced hearing loss at the low and middle frequencies. Hearing loss induced by cisplatin and AM630 in the rat was associated with increased expression of genes for oxidative stress and inflammatory proteins in the rat cochlea. In vitro studies indicate that JWH015 did not alter cisplatin-induced killing of cancer cells suggesting this agent could be safely used during cisplatin chemotherapy. These data unmask a protective role of the cochlear endocannabinoid/CB2R system which appears tonically active under normal conditions to preserve normal hearing. However, an exogenous agonist is needed to boost the activity of endocannabinoid/CB2R system for protection against a more traumatic cochlear insult, as observed with cisplatin administration.

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).

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.

Medical cannabis in the treatment of cancer pain and spastic conditions and options of drug delivery in clinical practice

The use of cannabis for medical purposes has been recently legalised in many countries including the Czech Republic. As a result, there is increased interest on the part of physicians and patients in many aspects of its application. This mini review briefly covers the main active substances of the cannabis plant and mechanisms of action. It focuses on two conditions, cancer pain and spasticity in multiple sclerosis, where its effects are well-documented. A comprehensive overview of a few cannabis-based products and the basic pharmacokinetics of marijuana's constituents follows. The review concludes with an outline for preparing cannabis (dried inflorescence) containing drug dosage forms that can be produced in a hospital pharmacy.

Sex-Dependent Effects of Cannabis and Cannabinoids: A Translational Perspective

Recent policy changes have led to significant increases in the use of cannabis for both medical and recreational purposes. Although men are more likely to endorse past month cannabis use and are more frequently diagnosed with Cannabis Use Disorder relative to women, a growing proportion of medical cannabis users are reported to be women. The increased popularity of cannabis for medical purposes and the narrowing gap in prevalence of use between men and women raises questions regarding sex-dependent effects related to therapeutic efficacy and negative health effects of cannabis and cannabinoids. The objective of this review is to provide a translational perspective on the sex-dependent effects of cannabis and cannabinoids by synthesizing findings from preclinical and clinical studies focused on sex comparisons of their therapeutic potential and abuse liability, two specific areas that are of significant public health relevance. Hormonal and pharmacological mechanisms that may underlie sex differences in the effects of cannabis and cannabinoids are highlighted.

Review: The Role of Cannabinoids on Esophageal Function-What We Know Thus Far

The endocannabinoid system (ECS) primarily consists of cannabinoid receptors (CBRs), endogenous ligands, and enzymes for endocannabinoid biosynthesis and inactivation. Although the presence of CBRs, both CB1 and CB2, as well as a third receptor (G-protein receptor 55 [GPR55]), has been established in the gastrointestinal (GI) tract, few studies have focused on the role of cannabinoids on esophageal function. To date, studies have shown their effect on GI motility, inflammation and immunity, intestinal and gastric acid secretion, nociception and emesis pathways, and appetite control. Given the varying and sometimes limited efficacy of current medical therapies for diseases of the esophagus, further understanding and investigation into the interplay of the ECS on esophageal health and disease may present new therapeutic modalities that may help advance current treatment options. In this brief review, the current understanding of the ECS role in various esophageal functions and disorders is presented.

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.

The endocannabinoid system, a novel and key participant in acupuncture's multiple beneficial effects

Acupuncture and its modified forms have been used to treat multiple medical conditions, but whether the diverse effects of acupuncture are intrinsically linked at the cellular and molecular level and how they might be connected have yet to be determined. Recently, an emerging role for the endocannabinoid system (ECS) in the regulation of a variety of physiological/pathological conditions has been identified. Overlap between the biological and therapeutic effects induced by ECS activation and acupuncture has facilitated investigations into the participation of ECS in the acupuncture-induced beneficial effects, which have shed light on the idea that the ECS may be a primary mediator and regulatory factor of acupuncture's beneficial effects. This review seeks to provide a comprehensive summary of the existing literature concerning the role of endocannabinoid signaling in the various effects of acupuncture, and suggests a novel notion that acupuncture may restore homeostasis under different pathological conditions by regulating similar networks of signaling pathways, resulting in the activation of different reaction cascades in specific tissues in response to pathological insults.