High fat-fed GPR55 null mice display impaired glucose tolerance without concomitant changes in energy balance or insulin sensitivity but are less responsive to the effects of the cannabinoids rimonabant or Δ(9)-tetrahydrocannabivarin on weight gain

The role of tetrahydrocannabivarin (THCV) in metabolic disorders: A promising cannabinoid for diabetes and weight management

Disorders of the metabolism, including obesity and type 2 diabetes, represent significant global health challenges due to their rising prevalence and associated complications. Despite existing therapeutic strategies, including lifestyle interventions, pharmacological treatments, and surgical options, limitations such as poor adherence, side effects, and accessibility issues call attention to the need for novel solutions. Tetrahydrocannabivarin (THCV), a non-psychoactive cannabinoid derived from Cannabis sativa, has emerged as a promising agent to manage metabolic disorders. Unlike tetrahydrocannabinol (THC), THCV exhibits an antagonistic function on the CB1 receptor and a partial agonist function on the CB2 receptor, thus enabling appetite suppression, enhanced glucose regulation, and increased energy expenditure. Preclinical studies demonstrated that THCV improves insulin sensitivity, promotes glucose uptake, and restores insulin signaling in metabolic tissues. Additionally, THCV reduces lipid accumulation and improves the mitochondrial activity in adipocytes and hepatocytes, shown through both cell-based and animal research. Animal models further revealed THCV's potential to suppress appetite, prevent hepatosteatosis, and improve metabolic homeostasis. Preliminary human trials support these findings, thereby showing that THCV may modulate appetite and glycemic control, though larger-scale studies are necessary to confirm its clinical efficacy and safety. THCV's unique pharmacological profile positions it as a possible therapeutic candidate to address the multifaceted challenges of obesity and diabetes. Continued research should concentrate on optimizing formulations, undertaking well-designed clinical studies, and addressing regulatory hurdles to unlock its full potential.

Pharmacology of Non-Psychoactive Phytocannabinoids and Their Potential for Treatment of Cardiometabolic Disease

The use of Cannabis sativa by humans dates back to the third millennium BC, and it has been utilized in many forms for multiple purposes, including production of fibre and rope, as food and medicine, and (perhaps most notably) for its psychoactive properties for recreational use. The discovery of Δ9-tetrahydrocannabinol (Δ9-THC) as the main psychoactive phytocannabinoid contained in cannabis by Gaoni and Mechoulam in 1964 (J Am Chem Soc 86, 1646-1647), was the first major step in cannabis research; since then the identification of the chemicals (phytocannabinoids) present in cannabis, the classification of the pharmacological targets of these compounds and the discovery that the body has its own endocannabinoid system (ECS) have highlighted the potential value of cannabis-derived compounds in the treatment of many diseases, such as neurological disorders and cancers. Although the use of Δ9-THC as a therapeutic agent is constrained by its psychoactive properties, there is growing evidence that non-psychoactive phytocannabinoids, derived from both Cannabis sativa and other plant species, as well as non-cannabinoid compounds found in Cannabis sativa, have real potential as therapeutics. This chapter will focus on the possibilities for using these compounds in the prevention and treatment of cardiovascular disease and related metabolic disturbances.

Global deletion of G protein-coupled receptor 55 impairs glucose homeostasis during obesity by reducing insulin secretion and β-cell turnover

AIM

To investigate the effect of G protein-coupled receptor 55 (GPR55) deletion on glucose homeostasis and islet function following diet-induced obesity.

METHODS

GPR55-/- and wild-type (WT) mice were fed ad libitum either standard chow (SC) or a high-fat diet (HFD) for 20 weeks. Glucose and insulin tolerance tests were performed at 9/10 and 19/20 weeks of dietary intervention. Insulin secretion in vivo and dynamic insulin secretion following perifusion of isolated islets were also determined, as were islet caspase-3/7 activities and β-cell 5-bromo-20-deoxyuridine (BrdU) incorporation.

RESULTS

GPR55-/- mice fed a HFD were more susceptible to diet-induced obesity and were more glucose intolerant and insulin resistant than WT mice maintained on a HFD. Islets isolated from HFD-fed GPR55-/- mice showed impaired glucose- and pcacahorbol 12-myristate 13-acetate-stimulated insulin secretion, and they also displayed increased cytokine-induced apoptosis. While there was a 5.6 ± 1.6-fold increase in β-cell BrdU incorporation in the pancreases of WT mice fed a HFD, this compensatory increase in β-cell proliferation in response to the HFD was attenuated in GPR55-/- mice.

CONCLUSIONS

Under conditions of diet-induced obesity, GPR55-/- mice show impaired glucose handling, which is associated with reduced insulin secretory capacity, increased islet cell apoptosis and insufficient compensatory increases in β-cell proliferation. These observations support that GPR55 plays an important role in positively regulating islet function.

The Role of Cannabidiol in Liver Disease: A Systemic Review

Cannabidiol (CBD), a non-psychoactive phytocannabinoid abundant in Cannabis sativa, has gained considerable attention for its anti-inflammatory, antioxidant, analgesic, and neuroprotective properties. It exhibits the potential to prevent or slow the progression of various diseases, ranging from malignant tumors and viral infections to neurodegenerative disorders and ischemic diseases. Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), alcoholic liver disease, and viral hepatitis stand as prominent causes of morbidity and mortality in chronic liver diseases globally. The literature has substantiated CBD's potential therapeutic effects across diverse liver diseases in in vivo and in vitro models. However, the precise mechanism of action remains elusive, and an absence of evidence hinders its translation into clinical practice. This comprehensive review emphasizes the wealth of data linking CBD to liver diseases. Importantly, we delve into a detailed discussion of the receptors through which CBD might exert its effects, including cannabinoid receptors, CB1 and CB2, peroxisome proliferator-activated receptors (PPARs), G protein-coupled receptor 55 (GPR55), transient receptor potential channels (TRPs), and their intricate connections with liver diseases. In conclusion, we address new questions that warrant further investigation in this evolving field.

Toxicological Evaluation and Pain Assessment of Four Minor Cannabinoids Following 14-Day Oral Administration in Rats

Introduction: Despite growing consumer interest and market availability, the safety of minor cannabinoids, generally present in low concentrations in Cannabis sativa L., is not well understood. Materials and Methods: Cannabichromene (CBC; 3.2, 10, 17, 22, 32, or 100 mg/kg-bw/day), cannabinol (CBN; 1, 3.2, 10, 17, 32, or 100 mg/kg-bw/day), delta-8-tetrahydrocannabinol (D8-THC; 0.32, 1, 3.2, or 10 mg/kg-bw/day), tetrahydrocannabivarin (THCV; 3.2, 10, 17, 22, 32, or 100 mg/kg-bw/day), and vehicle (medium-chain triglyceride oil) preparations were administered via oral gavage once daily for 14 days to Sprague Dawley rats. Changes in behavior, body weight, food consumption, clinical pathology, organ weights, body temperature, and thermal pain sensitivity (tail flick assay) were assessed. Select organ tissues were collected at terminal necropsy and fixed for histopathological examination. Results: No treatment-related deaths were observed throughout the study, and cannabinoids were generally well tolerated. While some significant trends in body weight differences from controls (increases and decreases) were observed, these occurred independently of food consumption. Overall, differences in serum chemistry and hematology parameters between cannabinoid groups and their respective control groups were considered to occur due to biological variation among rats. No treatment-related gross abnormalities were observed in examined organs. Significant changes in absolute and relative organ weights occurred primarily in males and were generally of negligible magnitude. There were no biologically significant histopathological observations. While pain tolerance was significantly improved in animals treated with D8-THC (3.2 and 10 mg/kg-bw/day, day 14), results across minor cannabinoids were inconsistent and warrant further study. Conclusion: Minor cannabinoids were well tolerated across 14 days of daily oral administration at the doses assessed. Modest, dose-dependent trends in relative organ weights and serum chemistry parameters warrant exploration at higher oral doses. These data will assist in dose selection for future studies investigating the long-term safety and effects of CBC, CBN, D8-THC, and THCV.

Pharmacological Activation of GPR55 Improved Cognitive Impairment Induced by Lipopolysaccharide in Mice

Our previous research found that activation of GPR55 can alleviate cognitive impairment induced by amyloid-beta 1-42 (Aβ_1-42) and streptozotocin in mice, but the role of GPR55 in the pathogenesis of cognitive impairment remains unknown. Here, we used a lipopolysaccharide (LPS) mouse model to further investigate the role and mechanism of O-1602, a GPR55 agonist, on cognitive dysfunction. ICR mice were treated with an intracerebroventricular (i.c.v.) injection of LPS, followed by cognitive function tests. The expression of GPR55, NF-κB p65, caspase-3, Bax, and Bcl-2 in the hippocampus was examined by Western blotting. Inflammatory cytokines and microglia were detected by ELISA kit and immunohistochemical analyses, respectively. The levels of MDA, GSH, SOD, and CAT were examined by assay kits. Furthermore, TUNEL-staining was used to detect neuronal apoptosis. Our results showed that i.c.v. injection of LPS in mice exhibited impaired performance in the behavior tests, which were ameliorated by O-1602 treatment (2.0 or 4.0 μg/mouse, i.c.v.). Importantly, we found that O-1602 treatment reversed GPR55 downregulation, decreased the expression of NF-κB p65, suppressed the accumulation of proinflammatory cytokines and microglia activation, increased the anti-inflammatory cytokines, and reduced the levels of MDA, increased the levels of GSH, SOD, and CAT in the hippocampus. In addition, O-1602 treatment also significantly reduced Bax and increased Bcl-2 expression as well as decreased caspase-3 activity and TUNEL-positive cells in the hippocampus. These observations indicate that O-1602 may ameliorate LPS-induced cognition deficits via inhibiting neuroinflammation, oxidative stress, and apoptosis mediated by the NF-κB pathway in mice.

Pharmacological and Toxicological Effects of Phytocannabinoids and Recreational Synthetic Cannabinoids: Increasing Risk of Public Health

Synthetic Cannabinoids (CBs) are a novel class of psychoactive substances that have rapidly evolved around the world with the addition of diverse structural modifications to existing molecules which produce new structural analogues that can be associated with serious adverse health effects. Synthetic CBs represent the largest class of drugs detected by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) with a total of 207 substances identified from 2008 to October 2020, and 9 compounds being reported for the first time. Synthetic CBs are sprayed on natural harmless herbs with an aim to mimic the euphoric effect of Cannabis. They are sold under different brand names including Black mamba, spice, K2, Bombay Blue, etc. As these synthetic CBs act as full agonists at the CB receptors, they are much more potent than natural Cannabis and have been increasingly associated with acute to chronic intoxications and death. Due to their potential toxicity and abuse, the US government has listed some synthetic CBs under schedule 1 classification. The present review aims to provide a focused overview of the literature concerning the development of synthetic CBs, their abuse, and potential toxicological effects including renal toxicity, respiratory depression, hyperemesis syndrome, cardiovascular effects, and a range of effects on brain function.