Cannabinoid-1 receptor blockade in cardiometabolic risk reduction: safety, tolerability, and therapeutic potential

Cannabinol (CBN; 30 and 300 mg) effects on sleep and next-day function in insomnia disorder ('CUPID' study): protocol for a randomised, double-blind, placebo-controlled, cross-over, three-arm, proof-of-concept trial

OBJECTIVE

Insomnia is the most prevalent sleep disorder, with few effective pharmacotherapies. Anecdotal reports and recent preclinical research suggest that cannabinol (CBN), a constituent of Cannabis sativa derived from delta-9-tetrahydrocannabinol, could be an effective treatment. Despite this, the isolated effects of CBN on sleep have yet to be systematically studied in humans.

METHODS

The present protocol paper describes a randomised, double-blind, placebo-controlled, single-dose, three-arm, cross-over, proof-of-concept study which investigates the effects of CBN on sleep and next-day function in 20 participants with clinician-diagnosed insomnia disorder and an Insomnia Severity Index Score ≥15. Participants receive a single fixed oral liquid dose of 30 mg CBN, 300 mg CBN and matched placebo, in random order on three treatment nights; each separated by a 2-week wash-out period. Participants undergo overnight sleep assessment using in-laboratory polysomnography and next-day neurobehavioural function tests. The primary outcome is wake after sleep onset minutes. Secondary outcomes include changes to traditional sleep staging, sleep-onset latency and absolute spectral power during non-rapid eye movement (NREM) sleep. Tertiary outcomes include changes to sleep spindles during NREM sleep, arousal indices, absolute spectral power during REM sleep and subjective sleep quality. Safety-related and exploratory outcomes include changes to next-day simulated driving performance, subjective mood and drug effects, postural sway, alertness and reaction time, overnight memory consolidation, pre and post-sleep subjective and objective sleepiness; and plasma, urinary, and salivary cannabinoid concentrations. The study will provide novel preliminary data on CBN efficacy and safety in insomnia disorder, which will inform larger clinical trials.

ETHICS AND DISSEMINATION

Human Research Ethics Committee approval has been granted by Bellberry (2021-08-907). Study findings will be disseminated in a peer-reviewed journal and at academic conferences.

TRIAL REGISTRATION NUMBER

NCT05344170.

An α-hemoglobin-derived peptide (m)VD-hemopressin (α) promotes NREM sleep via the CB1 cannabinoid receptor

Hemopressin and related peptides have shown to function as the endogenous ligands or the regulator of cannabinoid receptors. The previous studies demonstrated that the endocannabinoid system played important roles in modulating several physiological functions such as sleep, olfaction, emotion, learning and memory, and reward behaviors. Mouse VD-hemopressin (α) [(m)VD-HPα], an 11-residue peptide derived from the α1 chain of hemoglobin, was recently presumed as a selective agonist of the CB₁ receptor. The present study was undertaken to investigate the effects of (m)VD-HPα on the sleep-wake cycle and power spectrum of cortical EEG in freely moving rats and the potential neurons in the brain activated by (m)VD-HPα. The results showed that 20.1 nmol of (m)VD-HPα i.c.v. administration increased non-rapid eye movement (NREM) sleep in the first 2 h section accompanied by an increase in EEG delta (0.5-4 Hz) activity. The (m)VD-HPα-induced NREM sleep enhancement was due to extended episode duration instead of the episode number. In addition, the effect of (m)VD-HPα (20.1 nmol) on sleep-wake states was significantly attenuated by an antagonist of the CB₁ receptor, AM251 (20 nmol, i.c.v.) but not by the CB₂ receptor antagonist, AM630 (20 nmol, i.c.v.). In comparison with vehicle, (m)VD-HPα increased Fos-immunoreactive (-ir) neurons in the ventrolateral preoptic nucleus (VLPO), but reduced Fos-ir neurons in the lateral hypothalamus (LH), tuberomammillary nucleus (TMN), and locus coeruleus (LC). These findings suggest that (m)VD-HPα promotes NREM sleep via the CB₁ cannabinoid receptor to probably activate VLPO GABAergic neurons, but inactivates the LH orexinergic, LC noradrenergic, and TMN histaminergic neurons.

Off-label and investigational drugs in the treatment of alcohol use disorder: A critical review

Compounds known to be successful in the treatment of alcohol use disorder include the aversive agent, Disulfiram, the glutamatergic NMDA receptor antagonist, Acamprosate, and the opioid receptor antagonists, Naltrexone and Nalmefene. Although all four are effective in maintaining abstinence or reduction of alcohol consumption, only a small percentage of patients receive pharmacological treatment. In addition, many other medications have been investigated for their therapeutic potential in the treatment of alcohol use disorder. In this review we summarize and compare Baclofen, Gabapentin, Topiramate, Ondansetron, Varenicline, Aripiprazole, Quetiapine, Clozapine, Antidepressants, Lithium, Neuropeptide Y, Neuropeptide S, Corticotropin-releasing factor antagonists, Oxytocin, PF-05190457, Memantine, Ifenprodil, Samidorphan, Ondelopran, ABT-436, SSR149415, Mifepristone, Ibudilast, Citicoline, Rimonabant, Surinabant, AM4113 and Gamma-hydroxybutyrate While some have shown promising results in the treatment of alcohol use disorder, others have disappointed and should be excluded from further investigation. Here we discuss the most promising results and highlight medications that deserve further preclinical or clinical study. Effective, patient-tailored treatment will require greater understanding provided by many more preclinical and clinical studies.

Cannabinoids, Insomnia, and Other Sleep Disorders

Sleep disturbances are often cited as a primary reason for medicinal cannabis use, and there is increasing clinical interest in the therapeutic potential of cannabinoids in treating sleep disorders. Burgeoning evidence suggests a role of the endocannabinoid system in regulating the circadian sleep-wake cycle, highlighting a potential avenue for developing novel therapeutics. Despite widespread use of cannabis products as sleep aids globally, robustly designed studies verifying efficacy in sleep-disordered populations are limited. Although some study outcomes have suggested cannabinoid utility in insomnia disorder and sleep apnea, most studies to date are limited by small sample sizes, lack of rigorously controlled study designs, and high risk of bias. This critical review summarizes the current evidence for the use of cannabinoids as a treatment for sleep disorders and provides an overview of endocannabinoid modulation of sleep-wake cycles, as well as the sleep-modulating effects of plant-derived cannabinoids such as delta-9-tetrahydrocannbinol, cannabidiol, and cannabinol. The review also discusses practical considerations for clinicians regarding cannabinoid formulations, routes of administration, respiratory concerns, dosing, potential side effects, drug interactions, and effects relevant to driving, tolerance, and withdrawal. Although current interest in, and uptake of, medicinal cannabis use for sleep disorders may have surpassed the evidence base, there is a strong rationale for continued investigation into the therapeutic potential of cannabinoids.

CB1Rs in VMH neurons regulate glucose homeostasis but not body weight

Cannabinoid 1 receptor (CB1R) inverse agonists reduce body weight and improve several parameters of glucose homeostasis. However, these drugs have also been associated with deleterious side effects. CB1R expression is widespread in the brain and in peripheral tissues, but whether specific sites of expression can mediate the beneficial metabolic effects of CB1R drugs, while avoiding the untoward side effects, remains unclear. Evidence suggests inverse agonists may act on key sites within the central nervous system to improve metabolism. The ventromedial hypothalamus (VMH) is a critical node regulating energy balance and glucose homeostasis. To determine the contributions of CB1Rs expressed in VMH neurons in regulating metabolic homeostasis, we generated mice lacking CB1Rs in the VMH. We found that the deletion of CB1Rs in the VMH did not affect body weight in chow- and high-fat diet-fed male and female mice. We also found that deletion of CB1Rs in the VMH did not alter weight loss responses induced by the CB1R inverse agonist SR141716. However, we did find that CB1Rs of the VMH regulate parameters of glucose homeostasis independent of body weight in diet-induced obese male mice.NEW & NOTEWORTHY Cannabinoid 1 receptors (CB1Rs) regulate metabolic homeostasis, and CB1R inverse agonists reduce body weight and improve parameters of glucose metabolism. However, the cell populations expressing CB1Rs that regulate metabolic homeostasis remain unclear. CB1Rs are highly expressed in the ventromedial hypothalamic nucleus (VMH), which is a crucial node that regulates metabolism. With CRISPR/Cas9, we generated mice lacking CB1Rs specifically in VMH neurons and found that CB1Rs in VMH neurons are essential for the regulation of glucose metabolism independent of body weight regulation.

Cannabinoids, Endocannabinoids and Sleep

Sleep is a vital function of the nervous system that contributes to brain and bodily homeostasis, energy levels, cognitive ability, and other key functions of a variety of organisms. Dysfunctional sleep induces neural problems and is a key part of almost all human psychiatric disorders including substance abuse disorders. The hypnotic effects of cannabis have long been known and there is increasing use of phytocannabinoids and other formulations as sleep aids. Thus, it is crucial to gain a better understanding of the neurobiological basis of cannabis drug effects on sleep, as well as the role of the endogenous cannabinoid system in sleep physiology. In this review article, we summarize the current state of knowledge concerning sleep-related endogenous cannabinoid function derived from research on humans and rodent models. We also review information on acute and chronic cannabinoid drug effects on sleep in these organisms, and molecular mechanisms that may contribute to these effects. We point out the potential benefits of acute cannabinoids for sleep improvement, but also the potential sleep-disruptive effects of withdrawal following chronic cannabinoid drug use. Prescriptions for future research in this burgeoning field are also provided.

Dual inhibition of cannabinoid CB1 receptor and inducible NOS attenuates obesity-induced chronic kidney disease

Background and Purpose

Obesity, an important risk factor for developing chronic kidney disease (CKD), affects the kidneys by two main molecular signalling pathways: the endocannabinoid/CB₁ receptor system, whose activation in obesity promotes renal inflammation, fibrosis, and injury, and the inducible NOS (iNOS), which generates ROS resulting in oxidative stress. Hence, a compound that inhibits both peripheral CB₁ receptors and iNOS may serve as an effective therapeutic agent against obesity‐induced CKD.

Experimental Approach

Here, we describe the effect of a novel peripherally restricted, orally bioavailable dual CB₁ receptor/iNOS antagonist, MRI‐1867 (3 mg·kg⁻¹), in ameliorating obesity‐induced CKD, and compared its metabolic and renal efficacies to a stand‐alone peripheral CB₁ receptor antagonist (JD5037; 3 mg·kg⁻¹), iNOS antagonist (1400W; 10 mg·kg⁻¹), and pair feeding. Mice with high‐fat diet‐induced obesity were treated orally with these compounds or vehicle (Veh) for 28 days. Standard diet‐fed mice treated with Veh served as controls.

Key Results

Enhanced expression of CB₁ receptors and iNOS in renal tubules was found in human kidney patients with obesity and other CKDs. The hybrid inhibitor ameliorated obesity‐induced kidney morphological and functional changes via decreasing kidney inflammation, fibrosis, oxidative stress, and renal injury. Some of these features were independent of the improved metabolic profile mediated via inhibition of CB₁ receptors. An additional interesting finding is that these beneficial effects on the kidney were partially associated with modulating renal adiponectin signalling.

Conclusions and Implications

Collectively, our results highlight the therapeutic relevance of blocking CB₁ receptors and iNOS in ameliorating obesity‐induced CKD.

Targeting the endocannabinoid/CB1 receptor system for treating obesity in Prader-Willi syndrome

Objective

Extreme obesity is a core phenotypic feature of Prader–Willi syndrome (PWS). Among numerous metabolic regulators, the endocannabinoid (eCB) system is critically involved in controlling feeding, body weight, and energy metabolism, and a globally acting cannabinoid-1 receptor (CB₁R) blockade reverses obesity both in animals and humans. The first-in-class CB₁R antagonist rimonabant proved effective in inducing weight loss in adults with PWS. However, it is no longer available for clinical use because of its centrally mediated, neuropsychiatric, adverse effects.

Methods

We studied eCB ‘tone’ in individuals with PWS and in the Magel2-null mouse model that recapitulates the major metabolic phenotypes of PWS and determined the efficacy of a peripherally restricted CB₁R antagonist, JD5037 in treating obesity in these mice.

Results

Individuals with PWS had elevated circulating levels of 2-arachidonoylglycerol and its endogenous precursor and breakdown ligand, arachidonic acid. Increased hypothalamic eCB ‘tone’, manifested by increased eCBs and upregulated CB₁R, was associated with increased fat mass, reduced energy expenditure, and decreased voluntary activity in Magel2-null mice. Daily chronic treatment of obese Magel2-null mice and their littermate wild-type controls with JD5037 (3 mg/kg/d for 28 days) reduced body weight, reversed hyperphagia, and improved metabolic parameters related to their obese phenotype.

Conclusions

Dysregulation of the eCB/CB₁R system may contribute to hyperphagia and obesity in Magel2-null mice and in individuals with PWS. Our results demonstrate that treatment with peripherally restricted CB₁R antagonists may be an effective strategy for the management of severe obesity in PWS.

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Circulating levels of endocannabinoids are increased in individuals with PWS.

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Magel2 is a negative regulator of hypothalamic endocannabinoid ‘tone’.

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Peripherally-restricted CB1 receptor blockade reverses obesity in Magel2-null mice.

Endocannabinoid Signaling Regulates Sleep Stability

The hypnogenic properties of cannabis have been recognized for centuries, but endogenous cannabinoid (endocannabinoid) regulation of vigilance states is poorly characterized. We report findings from a series of experiments in mice measuring sleep with polysomnography after various systemic pharmacological manipulations of the endocannabinoid system. Rapid, unbiased scoring of vigilance states was achieved using an automated algorithm that we devised and validated. Increasing endocannabinoid tone with a selective inhibitor of monoacyglycerol lipase (JZL184) or fatty acid amide hydrolase (AM3506) produced a transient increase in non-rapid eye movement (NREM) sleep due to an augmentation of the length of NREM bouts (NREM stability). Similarly, direct activation of type 1 cannabinoid (CB1) receptors with CP47,497 increased NREM stability, but both CP47,497 and JZL184 had a secondary effect that reduced NREM sleep time and stability. This secondary response to these drugs was similar to the early effect of CB1 blockade with the antagonist/inverse agonist AM281, which fragmented NREM sleep. The magnitude of the effects produced by JZL184 and AM281 were dependent on the time of day this drug was administered. While activation of CB1 resulted in only a slight reduction in gamma power, CB1 blockade had dramatic effects on broadband power in the EEG, particularly at low frequencies. However, CB1 blockade did not significantly reduce the rebound in NREM sleep following total sleep deprivation. These results support the hypothesis that endocannabinoid signaling through CB1 is necessary for NREM stability but it is not necessary for sleep homeostasis.

Angiotensin II-induced activation of central AT1 receptors exerts endocannabinoid-mediated gastroprotective effect in rats

The aim of the present study was to analyze whether angiotensin II via the endocannabinoid system can induce gastric mucosal protection, since transactivation of cannabinoid CB1 receptors by angiotensin AT1 receptor in CHO cells was described. Experimental ulcer was induced by acidified ethanol given orally in male Wistar rats, CB1(+/+) wild type and CB1(-/-) knockout mice. The compounds were administered intracerebroventricularly. It was found, that 1. Angiotensin II inhibited the ethanol-induced gastric lesions (11.9-191pmol); the effect of angiotensin II (191pmol) was inhibited by the CB1 receptor inverse agonist AM 251 (1.8nmol) and the inhibitor of diacylglycerol lipase (DAGL), tetrahydrolipstatin (0.2nmol). 2. Angiotensin II exerted gastroprotection in wild type, but not in CB1(-/-) mice. 3. The gastroprotective effect of angiotensin II (191pmol) was reduced by atropine (1mg/kg i.v.) and bilateral cervical vagotomy. In conclusion, stimulation of central angiotensin AT1 receptors via activation of cannabinoid CB1 receptors induces gastroprotection in a DAGL-dependent and vagus-mediated mechanism.

Homology modeling of cannabinoid receptors: discovery of cannabinoid analogues for therapeutic use

Cannabinoids represent a promising class of compounds for developing novel therapeutic agents. Since the isolation and identification of the major psychoactive component Δ(9)-THC in Cannabis sativa in the 1960s, numerous analogues of the classical plant cannabinoids have been synthesized and tested for their biological activity. These compounds primarily target the cannabinoid receptors 1 (CB1) and Cannabinoid receptors 2 (CB2). This chapter focuses on CB1. Despite the lack of crystal structures for CB1, protein-based homology modeling approaches and molecular docking methods can be used in the design and discovery of cannabinoid analogues. Efficient synthetic approaches for therapeutically interesting cannabinoid analogues have been developed to further facilitate the drug discovery process.

Endocannabinoid system in cardiovascular disorders - new pharmacotherapeutic opportunities

The long history of Cannabis sativa had its development stimulated and oriented for medicine after the discovery and chemical characterization of its main active ingredient, the 9-tetrahydrocannabinol (9-THC). Consequently, a binding site for 9-THC was identified in rat brains and the first cannabinoid receptor (CB1) was cloned, followed by the CB2 and by the discover of two endogenous agonists: anandamide and 2-arachidonoyl glycerol. Cannabinoid receptors, endocannabinoids and the enzymes that catalyze its synthesis and degradation constitute the endocannabinoid system (ECS), which plays an important role in the cardiovascular system. In vivo experiments with rats have demonstrated the action of anandamide and 2-AG on the development of atherosclerotic plaque, as well as an effect on heart rate, blood pressure, vasoactivity and energy metabolism (action in dyslipidemia and obesity). Recent studies with an antagonist of CB1 receptors showed that the modulation of ECS can play an important role in reducing cardiovascular risk in obese and dyslipidemic patients. Similarly, studies in rats have demonstrated the action of CB2 receptors in adhesion, migration, proliferation and function of immune cells involved in the atherosclerotic plaque formation process. The evidence so far gathered shows that the modulation of ECS (as agonism or antagonism of its receptors) is an enormous potential field for research and intervention in multiple areas of human pathophysiology. The development of selective drugs for the CB1 and CB2 receptors may open a door to new therapeutic regimens.This review article aims to address the key findings and evidences on the modulation of ECS, in order to prospect future forms of therapeutic intervention at the cardiovascular level. A recent, emerging, controversial and of undoubted scientific interest subject, which states as a potential therapeutic target to reach in the 21^st century.

Contribution of limbic norepinephrine to cannabinoid-induced aversion

RATIONALE

The cannabinoid system has risen to the forefront in the development of novel treatments for a number of pathophysiological processes. However, significant side effects have been observed in clinical trials raising concerns regarding the potential clinical utility of cannabinoid-based agents. Understanding the neural circuits and neurochemical substrates impacted by cannabinoids will provide a better means of gaging their actions within the central nervous system that may contribute to the expression of unwanted side effects.

OBJECTIVES

In the present study, we investigated whether norepinephrine (NE) in the limbic forebrain is a critical determinant of cannabinoid receptor agonist-induced aversion and anxiety in rats.

METHODS

An immunotoxin lesion approach was combined with behavioral analysis using a place conditioning paradigm and the elevated zero maze.

RESULTS

Our results show that the non-selective CB1/CB2 receptor agonist, WIN 55,212-2, produced a significant place aversion in rats. Further, NE in the nucleus accumbens was critical for WIN 55,212-2-induced aversion but did not affect anxiety-like behaviors. Depletion of NE from the bed nucleus of the stria terminalis was ineffective in altering WIN 55,212-2-induced aversion and anxiety.

CONCLUSIONS

These results indicate that limbic, specifically accumbal, NE is required for cannabinoid-induced aversion but is not essential to cannabinoid-induced anxiety.

Involvement of adipokines in rimonabant-mediated insulin sensitivity in ob/ob mice

Objectives

It has been recently reported that blockade of type 1 cannabinoid (CB1) receptors by specific antagonists or genetic manipulation alleviates dyslipidaemia, hyperglycaemia and insulin resistance in animal models of obesity and type 2 diabetes. However, the precise role of adipokines in the insulin-sensitising effects of the CB1 antagonist rimonabant is not clear.

Methods

ob/ob mice were treated with different doses of rimonabant and then subjected to an oral glucose tolerance test. The expression of different adipokines in white adipose tissue was analysed by quantitative real-time PCR.

Key findings

Rimonabant (30 mg/kg) significantly inhibited body weight and fat pad weight gain (P < 0.05) and improved glucose tolerance. Gene expression analysis indicated that tumour necrosis factor-α, visfatin and retinol binding protein-4 were downregulated in the adipose tissue of ob/ob mice treated with rimonabant compared with controls, whereas adiponectin was significantly upregulated.

Conclusions

Rimonabant-mediated alteration of adipokines in white adipose tissues may play a role in improving insulin sensitivity in obese animals.

Rimonabant: an antagonist drug of the endocannabinoid system for the treatment of obesity

Obesity, an ever-increasing problem in the industrialized world, has long been a target of research for a cure or, at least, control of its expansion. In the search for treatment, the recently discovered endocannabinoid system has emerged as a new target for controlling obesity and its associated conditions. The endocannabinoid system plays an important role in controlling weight and energy balance in humans. This system is activated to a greater extent in obese patients, and the specific blockage of its receptors is the aim of rimonabant, one of the most recent drugs created for the treatment of obesity. This drug acts as a blockade for endocannabinoid receptors found in the brain and peripheral organs that play an important role on carbohydrate and fat metabolism. Clinical studies have confirmed that, when used in combination with a low calorie diet, rimonabant promotes loss in body weight, loss in abdominal circumference, and improvements in dyslipidemia. Rimonabant is also being tested as a potential anti-smoking treatment since endocannabinoids are related to the pleasurable effect of nicotine. Thus, rimonabant constitutes a new therapeutic approach to obesity and cardiovascular risk factors. Studies show effectiveness in weight loss; however, side effects such as psychiatric alterations have been reported, including depression and anxiety. These side effects have led the FDA (Food and Drug Administration) to not approve this drug in the United States. For a more complete evaluation on the safety of this drug, additional studies are in progress.

Pharmacotherapy for cannabis dependence: how close are we?

Cannabis is the most widely used illicit drug in the world. Treatment admissions for cannabis use disorders have risen considerably in recent years, and the identification of medications that can be used to improve treatment outcomes among this population is a priority for researchers and clinicians. To date, several medications have been investigated for indications of clinically desirable effects among cannabis users (e.g. reduced withdrawal, attenuation of subjective or reinforcing effects, reduced relapse). Medications studied have included those: (i) known to be effective in the treatment of other drug use disorders; (ii) known to alleviate symptoms of cannabis withdrawal (e.g. dysphoric mood, irritability); or (iii) that directly affect endogenous cannabinoid receptor function. Results from controlled laboratory studies and small open-label clinical studies indicate that buspirone, dronabinol, fluoxetine, lithium and lofexidine may have therapeutic benefit for those seeking treatment for cannabis-related problems. However, controlled clinical trials have not been conducted and are needed to both confirm the potential clinical efficacy of these medications and to validate the laboratory models being used to study candidate medications. Although the recent increase in research towards the development of pharmacotherapy for cannabis use disorders has yielded promising leads, well controlled clinical trials are needed to support broad clinical use of these medications to treat cannabis use disorders.

Should peripheral CB(1) cannabinoid receptors be selectively targeted for therapeutic gain?

Endocannabinoids, endogenous lipid ligands of cannabinoid receptors, mediate a variety of effects similar to those of marijuana. Cannabinoid CB(1) receptors are highly abundant in the brain and mediate psychotropic effects, which limits their value as a potential therapeutic target. There is growing evidence for CB(1) receptors in peripheral tissues that modulate a variety of functions, including pain sensitivity and obesity-related hormonal and metabolic abnormalities. In this review we propose that selective targeting of peripheral CB(1) receptors has potential therapeutic value because it would help to minimize addictive, psychoactive effects in the case of CB(1) agonists used as analgesics, or depression and anxiety in the case of CB(1) antagonists used in the management of cardiometabolic risk factors associated with the metabolic syndrome.

Disrupting nicotine reinforcement: from cigarette to brain

Cigarette smoking is a tenacious addiction that is maintained to a significant extent by the reinforcing effects of nicotine. An emerging theme in smoking cessation treatment is the development of methods for interfering with these reinforcing effects. By attenuating nicotine reinforcement, treatments may enhance a smoker's chances of successfully remaining abstinent. Several treatment approaches will be described, including the use of denicotinized cigarettes, nicotine vaccines, nicotinic receptor agonists and antagonists, and modulators of brain reinforcement processes. These techniques highlight the numerous sites along the path between the cigarette and the brain that can be targeted for intervention. In addition to unimodal therapies, treatment combinations will be discussed that might more effectively block cigarette reward and thereby further enhance smoking abstinence.