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The Endocannabinoid System in Energy Homeostasis and the Etiopathology of Metabolic Disorders
Abstract
Endocannabinoids and cannabinoid CB1 receptors are known to play a generalized role in energy homeostasis. However, clinical trials with the first generation of CB1 blockers, now discontinued due to psychiatric side effects, were originally designed to reduce food intake and body weight rather than the metabolic risk factors associated with obesity. In this review, we discuss how, in addition to promoting energy intake, endocannabinoids control lipid and glucose metabolism in several peripheral organs, particularly the liver and adipose tissue. Direct actions in skeletal muscle and pancreas are also emerging. This knowledge may help in the design of future therapies for the metabolic syndrome.
... The endocannabinoid system (ECS) plays a vital role in regulating appetite, metabolic processes, and energy balance both centrally and peripherally [3]. ECS is composed of cannabinoid receptor type 1 (CB1) and cannabinoid receptor type 2 (CB2), endogenous ligands, i.e., endocannabinoids, and the enzymes that synthesize and degrade them [3]. ...
... The endocannabinoid system (ECS) plays a vital role in regulating appetite, metabolic processes, and energy balance both centrally and peripherally [3]. ECS is composed of cannabinoid receptor type 1 (CB1) and cannabinoid receptor type 2 (CB2), endogenous ligands, i.e., endocannabinoids, and the enzymes that synthesize and degrade them [3]. The endocannabinoids are bioactive lipids, the two most studied of which are N-arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol (2-AG) [3]. ...
... ECS is composed of cannabinoid receptor type 1 (CB1) and cannabinoid receptor type 2 (CB2), endogenous ligands, i.e., endocannabinoids, and the enzymes that synthesize and degrade them [3]. The endocannabinoids are bioactive lipids, the two most studied of which are N-arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol (2-AG) [3]. In recent years, additional receptors, enzymes, and "endocannabinoid-like" mediators have been identified as part of the extended ECS. ...
Prolonged cannabis users show a lower prevalence of obesity and associated comorbidities. In rodent models, Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) from the plant Cannabis sativa L. have shown anti-obesity properties, suggesting a link between the endocannabinoid system (ECS) and obesity. However, the oral administration route has rarely been studied in this context. The aim of this study was to investigate the effect of prolonged oral administration of pure THC and CBD on obesity-related parameters and peripheral endocannabinoids. C57BL/6 male mice were fed with either a high-fat or standard diet and then received oral treatment in ramping doses, namely 10 mg/kg of THC or CBD for 5 weeks followed by 30 mg/kg for an additional 5 weeks. Mice treated with THC had attenuated weight gain and improved glucose tolerance, followed by improvement in steatosis markers and decreased hypertrophic cells in adipose epididymal tissue. Mice treated with CBD had improved glucose tolerance and increased markers of lipid metabolism in adipose and liver tissues, but in contrast to THC, CBD had no effect on weight gain and steatosis markers. CBD exclusively decreased the level of the endocannabinoid 2-arachidonoylglycerol in the liver. These data suggest that the prolonged oral consumption of THC, but not of CBD, ameliorates diet-induced obesity and metabolic parameters, possibly through a mechanism of adipose tissue adaptation.
... The endocannabinoid system (ECS) plays a central role in regulating food intake, energy homeostasis, and lipid metabolism at both the central and peripheral level [3,4]. ECS consists of two G proteincoupled receptors: cannabinoid type 1 and type 2 (CB1R and CB2R, respectively) receptors, their ligands endocannabinoids, and the ligand-metabolizing enzymes [4]. ...
... The endocannabinoid system (ECS) plays a central role in regulating food intake, energy homeostasis, and lipid metabolism at both the central and peripheral level [3,4]. ECS consists of two G proteincoupled receptors: cannabinoid type 1 and type 2 (CB1R and CB2R, respectively) receptors, their ligands endocannabinoids, and the ligand-metabolizing enzymes [4]. CB1Rs, which are essential in energy homeostasis, are widely expressed in the central nervous system, notably in brain regions controlling energy balance and feeding behavior such as the hypothalamus, corticolimbic circuits, ventral tegmental area, and brain stem [5,6]. ...
... Endocannabinoids, of which the most studied are anandamide (AEA) and 2-arachidonoylglycerol (2-AG), act as ligands to CB1Rs, which exert a cascade promoting energy preservation leading to increased food intake, adipose tissue accumulation, increased levels of proinflammatory markers, decreased energy expenditure and thermogenesis, insulin resistance, and weight gain [3][4][5][6][7]. Endocannabinoids are synthesized and released locally on demand under tight regulation by neurons [3,4]. ...
Objective:
Cannabinoid type 1 receptors (CB1R) modulate feeding behavior and energy homeostasis, and the CB1R tone is dysgulated in obesity. This study aimed to investigate CB1R availability in peripheral tissue and brain in young men with overweight versus lean men.
Methods:
Healthy males with high (HR, n = 16) or low (LR, n = 20) obesity risk were studied with fluoride 18-labeled FMPEP-d2 positron emission tomography to quantify CB1R availability in abdominal adipose tissue, brown adipose tissue, muscle, and brain. Obesity risk was assessed by BMI, physical exercise habits, and familial obesity risk, including parental overweight, obesity, and type 2 diabetes. To assess insulin sensitivity, fluoro-[18 F]-deoxy-2-D-glucose positron emission tomography during hyperinsulinemic-euglycemic clamp was performed. Serum endocannabinoids were analyzed.
Results:
CB1R availability in abdominal adipose tissue was lower in the HR than in the LR group, whereas no difference was found in other tissues. CB1R availability of abdominal adipose tissue and brain correlated positively with insulin sensitivity and negatively with unfavorable lipid profile, BMI, body adiposity, and inflammatory markers. Serum arachidonoyl glycerol concentration was associated with lower CB1R availability of the whole brain, unfavorable lipid profile, and higher serum inflammatory markers.
Conclusions:
The results suggest endocannabinoid dysregulation already in the preobesity state.
... CB2 is also found on enteric neurons and on immune and epithelial cells in the GI tract [85]. When AEA and 2-AG trigger CB1 and CB2 receptors, the biochemical responses will frequently depend on the type of cell stimulated; the response varies from decreased levels of cAMP thought the inhibition of Ca2+ channels and adenylate cyclase activity to increased activity of mitogen-activated protein kinase pathways, phospholipases, and K+ channels [86]. ...
... Appetite and food intake are locally balanced by the activation of the CB1 receptor that modulates the activity of hypothalamic neurons that cause the release of orexigenic and anorexigenic neuropeptides as well as the function of the mesolimbic and brainstem neurons by directing information to these neurons from the periphery. Therefore, CB1 receptors are implicated both in the homeostatic and hedonic aspects of food intake [86]. ...
... The activation of glucose uptake, lipoprotein lipase, and fatty acid synthase; stimulation of PPARg expression and adipogenesis; inhibition of cAMP release, AMPK, and mitochondrial biogenesis; and inhibition of adiponectin production in hypertrophic adipocytes are the mechanisms described in the regulation of adipogenesis and lipogenesis. It was observed that, in animal and human obesity, the CB1 receptor expressed at the level of white adipocytes, WAT AEA, and 2-AG levels are usually deregulated [13,86,[92][93][94][95]. ...
The endocannabinoid system (ECS) is involved in various processes, including brain plasticity, learning and memory, neuronal development, nociception, inflammation, appetite regulation, digestion, metabolism, energy balance, motility, and regulation of stress and emotions. Physical exercise (PE) is considered a valuable non-pharmacological therapy that is an immediately available and cost-effective method with a lot of health benefits, one of them being the activation of the endogenous cannabinoids. Endocannabinoids (eCBs) are generated as a response to high-intensity activities and can act as short-term circuit breakers, generating antinociceptive responses for a short and variable period of time. A runner’s high is an ephemeral feeling some sport practitioners experience during endurance activities, such as running. The release of eCBs during sustained physical exercise appears to be involved in triggering this phenomenon. The last decades have been characterized by an increased interest in this emotional state induced by exercise, as it is believed to alleviate pain, induce mild sedation, increase euphoric levels, and have anxiolytic effects. This review provides information about the current state of knowledge about endocannabinoids and physical effort and also an overview of the studies published in the specialized literature about this subject.
... The ECS plays a pivotal role at both central and peripheral levels to generally decrease metabolism and increase energy storage in several organs (10) as well as decrease inflammation (11). Endocannabinoids (ECs; N-arachidonoylethanolamine [AEA] and 2-arachidonoylglycerol [2-AG]) are long-chain arachidonic acid (AA)-derived signaling lipids generally produced on demand from phospholipid precursors (12) and originally found to activate cannabinoid receptors type 1 and type 2 (CB1 and CB2) (13). ...
... To assess the direct effects of the different diets on the eCBome, we measured eCBome gene expression and mediator levels in the muscle, hypothalamus, liver, BAT, SCAT, and EPAT, because it is well established that endocannabinoids and related lipids play important roles in each of these tissues with respect to the regulation of various aspects of metabolism (7,10,12,16,18,20,25) and plasma (lipid levels only). As expected, we observed important changes in eCBome signaling with the hemp seed and linseed supplemented diets, which are rich in PUFAs. ...
... As expected, important changes in eCBome signaling under the hemp and linseed substituted diets, which are rich in PUFAs, were found in the present study. The ECS generally decreases energy expenditure and increases energy storage in several organs through the elevation of AEA and/or 2-AG levels and CB1 receptor activation (10). However, the ECS is now considered as part of a much larger signaling system, the eCBome, which, with its over 100 lipid mediators and about 13 molecular targets (including the PPARs, thermosensitive TRP channels such as TRPV1, and orphan GPCRs such as GPR119), is also deeply involved in energy metabolism control but often in ways opposite to endocannabinoid/CB1 signaling (63). ...
Omega-3 fatty acids support cardiometabolic health and reduce chronic low-grade inflammation. These fatty acids may impart their health benefits partly by modulating the endocannabinoidome and the gut microbiome, both of which are key regulators of metabolism and the inflammatory response. Whole hemp seeds ( Cannabis sativa ) are of exceptional nutritional value, being rich in omega-3 fatty acids. We assessed the effects of dietary substitution (equivalent to about 2 tablespoons of seeds a day for humans) of whole hemp seeds in comparison with whole linseeds in a diet-induced obesity mouse model and determined their effects on obesity and the gut microbiome-endocannabinoidome axis. We show that whole hemp seed substitution did not affect weigh gain, adiposity, or food intake, whereas linseed substitution did, in association with higher fasting glucose levels, greater insulin release during an oral glucose tolerance test, and higher levels of liver triglycerides than controls. Furthermore, hemp seed substitution mitigated diet-induced obesity-associated increases in intestinal permeability and circulating PAI-1 levels, while having no effects on markers of inflammation in epididymal adipose tissue, which were, however, increased in mice fed linseeds. Both hemp seeds and linseeds were able to modify the expression of several endocannabinoidome genes and markedly increased the levels of several omega-3 fatty acid–derived endocannabinoidome bioactive lipids with previously suggested anti-inflammatory actions in a tissue specific manner, despite the relatively low level of seed substitution. While neither diet markedly modified the gut microbiome, mice on the hemp seed diet had higher abundance of Clostridiaceae 1 and Rikenellaceae than mice fed linseed or control diet, respectively. Thus, hemp seed-containing foods might represent a source of healthy fats that are not likely to exacerbate the metabolic consequences of obesogenic diets while producing intestinal permeability protective effects and some anti-inflammatory actions.
... Yet, recent investigations discovered long-chain fatty acid amides and esters that often share biosynthetic or degradative enzymes with 2-AG and AEA and can thus considered to be part of the expanded eCB system (e.g., endocannabinoidome) [3]. Accumulating evidence highlights the essential role of the eCB system in multiple physiological functions such as energy homeostasis, food intake, sleep patterns, mood, and stress [4,5]. In addition, the eCB signaling is implicated in numerous pathophysiological processes, including respiratory, mental, cardiovascular, and cerebrovascular diseases [6]. ...
... In line with our findings, a study from the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohorts identified substantial differences between men and women in their associations of blood metabolome with A-T-N biomarkers [33]. Sex-specific differences were observed mainly in metabolites responsible for energy metabolism and homeostasis, processes that are regulated by eCBs [4,5]. Sex-specific differences has been shown in the expression and affinity of cannabis receptors in animals [34] and human brains [35]. ...
Background
Preclinical studies highlight the importance of endogenous cannabinoids (endocannabinoids; eCBs) in neurodegeneration. Yet, prior observational studies focused on limited outcome measures and assessed only few eCB compounds while largely ignoring the complexity of the eCB system. We examined the associations of multiple circulating eCBs and eCB-like molecules with early markers of neurodegeneration and neuro-injury and tested for effect modification by sex.
Methods
This exploratory cross-sectional study included a random sample of 237 dementia-free older participants from the Framingham Heart Study Offspring cohort who attended examination cycle 9 (2011–2014), were 65 years or older, and cognitively healthy. Forty-four eCB compounds were quantified in serum, via liquid chromatography high-resolution mass spectrometry. Linear regression models were used to examine the associations of eCB levels with brain MRI measures (i.e., total cerebral brain volume, gray matter volume, hippocampal volume, and white matter hyperintensities volume) and blood biomarkers of Alzheimer’s disease and neuro-injury (i.e., total tau, neurofilament light, glial fibrillary acidic protein and Ubiquitin C-terminal hydrolase L1). All models were adjusted for potential confounders and effect modification by sex was examined.
Results
Participants mean age was 73.3 ± 6.2 years, and 40% were men. After adjustment for potential confounders and correction for multiple comparisons, no statistically significant associations were observed between eCB levels and the study outcomes. However, we identified multiple sex-specific associations between eCB levels and the various study outcomes. For example, high linoleoyl ethanolamide (LEA) levels were related to decreased hippocampal volume among men and to increased hippocampal volume among women (β ± SE = − 0.12 ± 0.06, p = 0.034 and β ± SE = 0.08 ± 0.04, p = 0.026, respectively).
Conclusions
Circulating eCBs may play a role in neuro-injury and may explain sex differences in susceptibility to accelerated brain aging. Particularly, our results highlight the possible involvement of eCBs from the N-acyl amino acids and fatty acid ethanolamide classes and suggest specific novel fatty acid compounds that may be implicated in brain aging. Furthermore, investigation of the eCBs contribution to neurodegenerative disease such as Alzheimer’s disease in humans is warranted, especially with prospective study designs and among diverse populations, including premenopausal women.
... The endocannabinoid system (ECS) represents an endogenous signaling system demonstrated to play a key role in the regulation of appetite, metabolic processes, and energy balance. The ECS is made up of bioactive lipids, the endocannabinoids, enzymes that regulate their production and degradation, and receptors through which they transmit their signal [365]. The most studied and well-known receptors of the ECS are the G-protein-coupled receptors: cannabinoid receptor 1 (CBr1) and 2 (CBr2). ...
... Animal studies have shown that decreasing food intake and increasing energy consumption are correlated with the antagonism of CB1. This effect results in the improvement of different metabolic diseases [365]. In addition, the stimulation of adipocyte metabolism is correlated with the reduction in CB1 activity in visceral fat [371]. ...
In the current review, we focused on identifying aliment compounds and micronutrients, as well as addressed promising bioactive nutrients that may interfere with NAFLD advance and ultimately affect this disease progress. In this regard, we targeted: 1. Potential bioactive nutrients that may interfere with NAFLD, specifically dark chocolate, cocoa butter, and peanut butter which may be involved in decreasing cholesterol concentrations. 2. The role of sweeteners used in coffee and other frequent beverages; in this sense, stevia has proven to be adequate for improving carbohydrate metabolism, liver steatosis, and liver fibrosis. 3. Additional compounds were shown to exert a beneficial action on NAFLD, namely glutathione, soy lecithin, silymarin, Aquamin, and cannabinoids which were shown to lower the serum concentration of triglycerides. 4. The effects of micronutrients, especially vitamins, on NAFLD. Even if most studies demonstrate the beneficial role of vitamins in this pathology, there are exceptions. 5. We provide information regarding the modulation of the activity of some enzymes related to NAFLD and their effect on this disease. We conclude that NAFLD can be prevented or improved by different factors through their involvement in the signaling, genetic, and biochemical pathways that underlie NAFLD. Therefore, exposing this vast knowledge to the public is particularly important.
... The hypothalamus plays a key role in the context of exostatic functions, because increased food intake can be interpreted as a behavior bound by the change in the incentive property of external stimuli induced by the activation of the lateral hypothalamus (Trojniar and Wise, 1991;Berridge and Valenstein, 1991). On the other hand, the limbic system, has been linked to the food palatability (Jager and Witkamp, 2014;Silvestri and Di Marzo, 2013). Recently the role of the ECS in olfactory circuits and olfactory bulb, where exogenous and endogenous CB1 receptor agonists increase perception and attractiveness of both odors and food, has been described role (Soria-Gomez et al. 2014a). ...
... Increased endocannabinoid levels and CB1 receptor expression are hallmarks of obesity in rodents and humans, which strongly contribute not only to the development, but also to the maintenance of the pathology (Mazier et al. 2015;Silvestri and Di Marzo, 2013 Thus, we can argue the ECS plays a physiological role in promoting exostatic processes and energy accumulation, contributing to the development of obesity and metabolic disorders when the system is activetd beyond physiological levels. ...
Via modulation of neuronal activity by cannabinoid receptor type-1 (CB1), the endocannabinoid system represents a major brain modulatory system controlling memory functions. On the other hand, several reports point out a crucial role of hippocampal dopamine signaling in the regulation of memory related processes. Furthermore, recent evidence suggests that hippocampal cells expressing dopamine receptors do also posses CB1 receptors.The work presented in this Thesis aims at establishing a functional connection between CB1 receptor and dopaminoceptive signaling in the regulation of hippocampal related memory processes with particular enfasis on the cellular and sub-cellular mechanisms involved.In the first part of the thesis we observed that a mouse line lacking CB1 in dopamine receptor type- 1 cells (D1-CB1-KO) displayed impaired long-term novel object recognition memory (NOR) and, interestingly, viral-mediated re-expression of CB1 in D1-positive cells in the hippocampus of D1-CB1- KO mice reversed the NOR impairment present in these mice. Furthermore, we pointed out execessive hippocampal GABAA receptor activation and impaired in vivo long-term potentiation (LTP) in the CA3-CA1 pathway as the main cellular mechanisms for memory impairment in D1-CB1- KO. Thus, we provided functional evidence for the involvement of a small subclass of type-1 cannabinoid receptor (CB1)-expressing hippocampal interneurons in the modulation of specific hippocampal circuits in memory processes.The second part of the Thesis focused on subcellular location of CB1 activation in D1 positive cells. Indeed, besides the canonical regulation of neuronal activity by plasma membrane CB1 receptor, recent evidence suggests the involvement of mitochondrial CB1 receptor (mtCB1) in the regulation of bioenergetic processes which impacts on synaptic transmission and amnesic effects of cannabinoids. We found that mtCB1 receptors in hippocampal D1-positive neurons is not required for physiological regulation of memory formation per se but its activation is required for THC- induced memory impairment. Looking for the intracellular and intra-mitochondrial G-protein signaling involved in these processes, we developed a new chemogenetic strategy which specifically modulates the mitochondrial G-protein signaling and we observed its contribution in brain mitochondrial activity and cognitive functions. Specific chemogenetic activation of mitochondrial G- protein signaling results in increased mitochondrial respiration which in turns rescues THC-induced amnesic effect.Overall, the results of this Thesis indicate the mechanisms linking the diversity of cellular and subcellular CB1 receptors in higher brain functions, including learning and memory and provide the basis for the development of more selective and precise therapeutic strategies for cognitive disorders.
... Besides their central localization, CB1Rs are widely distributed in peripheral tissues (e.g., in human and murine skeletal muscle) where they are localized mainly in the cell membrane (pCB1R) [6,[14][15][16][17], but a subpopulation is present in the mitochondria (mtCB1R) as well. Here they are involved in cellular functions and energy metabolism [13,[18][19][20][21] exerting several biochemical effects, including ATP production, modulation of reactive oxygen species (ROS), and neuropeptide signaling [22]. ...
... The force-frequency relation in EDL was obtained with isometric contractions at 20, 40, 60, 80, 100, 120, 160 and 200 Hz, with trains of 200 ms duration, at 30 sec intervals. In SOL the protocol was 10,20,30,40,60,80, and 100 Hz, with trains of 500 ms duration, at 30 sec intervals. ...
The endocannabinoid system (ECS) refers to a widespread signaling system and its alteration is implicated in a growing number of human diseases. Cannabinoid receptors (CBRs) are highly expressed in the central nervous system and many peripheral tissues. Evidence suggests that CB1Rs are expressed in human and murine skeletal muscle mainly in the cell membrane, but a subpopulation is present also in the mitochondria. However, very little is known about the latter population. To date, the connection between the function of CB1Rs and the regulation of intracellular Ca2+ signaling has not been investigated yet. Tamoxifen-inducible skeletal muscle-specific conditional CB1 knock-down (skmCB1-KD, hereafter referred to as Cre+/−) mice were used in this study for functional and morphological analysis. After confirming CB1R down-regulation on the mRNA and protein level, we performed in vitro muscle force measurements and found that peak twitch, tetanus, and fatigue were decreased significantly in Cre+/− mice. Resting intracellular calcium concentration, voltage dependence of the calcium transients as well as the activity dependent mitochondrial calcium uptake were essentially unaltered by Cnr1 gene manipulation. Nevertheless, we found striking differences in the ultrastructural architecture of the mitochondrial network of muscle tissue from the Cre+/− mice. Our results suggest a role of CB1Rs in maintaining physiological muscle function and morphology. Targeting ECS could be a potential tool in certain diseases, including muscular dystrophies where increased endocannabinoid levels have already been described.
... De plus, les taux d'endocannabinoïdes augmentent de manière significative dans l'hypothalamus et le noyau accumbens en réponse au jeûne, revenant à la normale après la réalimentation, sans changement dans les zones cérébrales non impliquées dans la prise alimentaire [59]. Le système endocannabinoïde affecte également les circuits de récompense et de renforcement dans le système mésolimbique contribuant à une préférence pour les aliments très palatables [59,60]. ...
... De plus, les taux d'endocannabinoïdes augmentent de manière significative dans l'hypothalamus et le noyau accumbens en réponse au jeûne, revenant à la normale après la réalimentation, sans changement dans les zones cérébrales non impliquées dans la prise alimentaire [59]. Le système endocannabinoïde affecte également les circuits de récompense et de renforcement dans le système mésolimbique contribuant à une préférence pour les aliments très palatables [59,60]. Le récepteur CB 1 est majoritairement exprimé dans le cerveau, et dans une moindre mesure dans de nombreux autres tissus comme l'intestin, le foie, le tissu adipeux ou le système cardiovasculaire ; le récepteur CB2-R est, quant à lui essentiellement exprimé par les cellules du système immunitaire [61]. ...
Résumé
Face à l’augmentation de la prévalence de l’obésité et ses conséquences en termes de santé publique, il est nécessaire de toujours mieux en comprendre la physiopathologie afin de développer des stratégies thérapeutiques innovantes. Cette revue rappelle brièvement les différents mécanismes impliqués dans la physiopathologie de l’obésité, tant au niveau central (homéostatique et hédonique) que périphérique, en prenant en compte le rôle du microbiote intestinal. Les différentes stratégies thérapeutiques récentes, hors chirurgie, endoscopie et approches comportementales, sont ensuite passées en revue en mettant les approches pharmacologiques en regard des différents mécanismes de régulation neurohormonaux ou métaboliques ciblés, et en incluant les développements actuels concernant la modulation du microbiote intestinal.
... HFD was reported to activate the SNS as well as the eCB system [26,38,39]. Therefore, we challenged both dbh-CB1-KO and -WT mice with HFD treatment. ...
... 2.2. dbh-CB1-KO Mice Show Reduced Weight, Adiposity, and Increased BAT Thermogenesis on a High-Fat Diet HFD was reported to activate the SNS as well as the eCB system [26,38,39]. Therefore, we challenged both dbh-CB1-KO and -WT mice with HFD treatment. ...
High-calorie diets and chronic stress are major contributors to the development of obesity and metabolic disorders. These two risk factors regulate the activity of the sympathetic nervous system (SNS). The present study showed a key role of the cannabinoid type 1 receptor (CB1) in dopamine β-hydroxylase (dbh)-expressing cells in the regulation of SNS activity. In a diet-induced obesity model, CB1 deletion from these cells protected mice from diet-induced weight gain by increasing sympathetic drive, resulting in reduced adipogenesis in white adipose tissue and enhanced thermogenesis in brown adipose tissue. The deletion of CB1 from catecholaminergic neurons increased the plasma norepinephrine levels, norepinephrine turnover, and sympathetic activity in the visceral fat, which coincided with lowered neuropeptide Y (NPY) levels in the visceral fat of the mutant mice compared with the controls. Furthermore, the mutant mice showed decreased plasma corticosterone levels. Our study provided new insight into the mechanisms underlying the roles of the endocannabinoid system in regulating energy balance, where the CB1 deletion in dbh-positive cells protected from diet-induced weight gain via multiple mechanisms, such as increased SNS activity, reduced NPY activity, and decreased basal hypothalamic-pituitary-adrenal (HPA) axis activity.
... Fasting activates CB1R to induce food intake by regulating levels of appetite-stimulating factors [111]. Hunger is generally provoked by hormonal changes such as ghrelin increase and leptin decrease, but the eCBs 2-AG and AEA bind hypothalamic CB1R to trigger the hunger response [112]. Direct activation of CB1R by AEA stimulates food intake [113]. ...
... The influence of CB1R agonists, especially AEA and 2-AG, on adipogenesis and lipogenesis has been reported. Activation of these receptors by AEA and 2-AG in white adipose tissue in vitro prompts fatty acids (FA) synthesis, TG accumulation, and decreased lipolysis [112]. ...
Cannabinoids (CBs) are used to treat chronic pain, chemotherapy-induced nausea and vomiting, and multiple sclerosis spasticity. Recently, the medicinal use of CBs has attracted increasing interest as a new therapeutic in many diseases. Data indicate a correlation between CBs and PPARs via diverse mechanisms. Both the endocannabinoid system (ECS) and peroxisome proliferator-activated receptors (PPARs) may play a significant role in PCOS and PCOS related disorders, especially in disturbances of glucose-lipid metabolism as well as in obesity and fertility. Taking into consideration the ubiquity of PCOS in the human population, it seems indispensable to search for new potential therapeutic targets for this condition. The aim of this review is to examine the relationship between metabolic disturbances and obesity in PCOS pathology. We discuss current and future therapeutic interventions for PCOS and related disorders, with emphasis on the metabolic pathways related to PCOS pathophysiology. The link between the ECS and PPARs is a promising new target for PCOS, and we examine this relationship in depth.
... In the present study, after 3 weeks of cannabis oil administration, favorable changes were evident in the lipid profile and markers of liver damage and prevented the increase in serum endocannabinoid levels in SRD-fed rats. Furthermore, we observed an improvement in the hepatic lipid content, NAS, and enzyme activities involved in de novo lipogenesis and oxidation of fatty acids, highlighting the beneficial effects of the full-spectrum cannabis extract used in dyslipidemia, liver damage, hepatic steatosis, and Some studies have suggested that Δ9-THC and/or CBD cannabinoids increased HDL-c concentration, reduced lipid serum and hepatic triglyceride accumulation, and liver damage in other animal models [46][47][48]. Similarly, Silvestri et al. [49] revealed the positive influence of CBD on the liver, namely, the reduction of intracellular lipid content in an in vitro hepatosteatosis model. ...
Introduction
This study aimed to analyze the effects of cannabis oil (cannabidiol:tetrahydrocannabinol [CBD:THC], 2:1 ratio) on the mechanisms involved in hepatic steatosis and oxidative stress in an experimental model of metabolic syndrome (MS) induced by a sucrose-rich diet (SRD). We hypothesized that noninvasive oral cannabis oil administration improves hepatic steatosis through a lower activity of lipogenic enzymes and an increase in carnitine palmitoyltransferase-1 (CPT-1) enzyme activity involved in the mitochondrial oxidation of fatty acids. Furthermore, cannabis oil ameliorates liver oxidative stress through the regulation of the main regulatory factors involved, nuclear factor erythroid 2 (NrF2) and nuclear factor-kB (NF-κB) p65. For testing this hypothesize, a relevant experimental model of MS was induced by feeding rats with a SRD for 3 weeks.
Methods
Male Wistar rats were fed the following diets for 3 weeks: reference diet: standard commercial laboratory diet, SRD, and SRD + cannabis oil: noninvasive oral administration of 1 mg/kg body weight cannabis oil daily. The full-spectrum cannabis oil presents a total cannabinoid CBD:THC 2:1 ratio. Serum glucose, triglyceride, total cholesterol, HDL-cholesterol, LDL-cholesterol, uric acid, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase (AP), N-arachidonoylethanolamine or anandamide and 2-arachidonoylglycerol endocannabinoids levels, thiobarbituric acid reactive substance (TBARS) levels, and non-enzymatic antioxidant capacity (ferric ion-reducing antioxidant power [FRAP]) were evaluated. In the liver tissue: histology, nonalcoholic fatty liver disease activity score (NAS), triglycerides and cholesterol content, lipogenic enzyme activities (fatty acid synthase, acetyl-CoA carboxylase, malic enzyme, and glucose-6-phosphate dehydrogenase), enzyme related to mitochondrial fatty acid oxidation (CPT-1), reactive oxygen species, TBARS, FRAP, glutathione, catalase, glutathione peroxidase, and glutathione reductase enzyme activities. 4-hydroxynonenal, NrF2, and NF-κB p65 levels were analyzed by immunohistochemistry.
Results
The results showed that SRD-fed rats developed dyslipidemia, liver damage, hepatic steatosis (increase of key enzymes related to the novo fatty acid synthesis and decrease of key enzyme related to mitochondrial fatty acid oxidation), lipid peroxidation, and oxidative stress. Hepatic NrF2 expression was significantly decreased and NF-κB p65 expression was increased. Cannabis oil administration improved dyslipidemia, liver damage, hepatic steatosis, lipid peroxidation (improving enzymes involved in lipid metabolism), and oxidative stress. In the liver tissue, NrF2 expression increased, and NF-κB p65 expression was reduced.
Conclusion
The present study revealed new aspects of liver damage and steatosis, lipid peroxidation, and oxidative stress in dyslipidemic insulin-resistant SRD-fed rats. We demonstrated new properties and molecular mechanisms of cannabis oil (CBD:THC, 2:1 ratio) on lipotoxicity and hepatic oxidative stress in an experimental model of MS.
... The extension of the eCB system, the endocannabinoidome (eCBome), includes additional eCB congeners derived from long chain fatty acids, notably within the N-acyl-ethanolamines (NAEs) and the 2-monoacyl-glycerols (2-MAGs) families, as well as numerous other enzymes and receptors. This system shares several metabolic functions with the gut microbiota, such as energy metabolism, inflammation, and immunity [3][4][5] . An increasing amount of evidence points to a bidirectional relationship between gut microbiota activity and the host eCBome www.nature.com/scientificreports/ ...
The gut microbiota and the endocannabinoidome (eCBome) play important roles in regulating energy homeostasis, and both are closely linked to dietary habits. However, the complex and compositional nature of these variables has limited our understanding of their interrelationship. This study aims to decipher the interrelation between dietary intake and the gut microbiome–eCBome axis using two different approaches for measuring dietary intake: one based on whole food and the other on macronutrient intakes. We reveal that food patterns, rather than macronutrient intakes, were associated with the gut microbiome–eCBome axis in a sample of healthy men and women (n = 195). N-acyl-ethanolamines (NAEs) and gut microbial families were correlated with intakes of vegetables, refined grains, olive oil and meats independently of adiposity and energy intakes. Specifically, higher intakes in vegetables and olive oil were associated with increased relative abundance of Clostridiaceae, Veillonellaceae and Peptostreptococaceae, decreased relative abundance of Acidominococaceae, higher circulating levels of NAEs, and higher HDL and LDL cholesterol levels. Our findings highlight the relative importance of food patterns in determining the gut microbiome–eCBome axis. They emphasize the importance of recognizing the contribution of dietary habits in these systems to develop personalized dietary interventions for preventing and treating metabolic disorders through this axis.
... Factually, relevant research has unveiled valuable clarifying snippets in terms of delineating many diseases pathways, including adipose tissue-related mechanisms regulating energy homeostasis (28). The eCBS mediators are the endocannabinoids, AEA and 2-arachidonoyl-glycerol, which are critical regulators of the WAT and often dysregulated in obesity (23,(28)(29)(30). AEA levels increase during adipogenesis (31), and this eCB is suggested to upregulate this process through activation of cannabinoid receptor 1 and peroxisome proliferator-activated receptor gamma (PPARG) (20,32,33). ...
... Endocannabinoids, anandamide (AEA), and 2-arachidonoylglycerol (2-AG) are endogenous ligands of CB receptors. They are synthesized "on demand" by postsynaptic cells without intermediate storage in synaptic vesicles, and they are released into the synaptic cleft, where they act as backward synaptic transmitters by binding to CB receptors situated on presynaptic terminals of neurons [13][14][15][16][17][18][19]. Some synthetic cannabinoids (i.e., nabilone, dronabinol) are already used in the treatment of drug-resistant epilepsy, vomiting, nausea, anorexia, and in multiple sclerosis, but it is also the fastest-growing group of illicit compounds with an alarming side effect profile that is often difficult to explain by the established molecular mechanisms of cannabinoid pharmacology. ...
Cannabinoids are active substances present in plants of the Cannabis genus. Both the Food and Drug Administration (FDA) and European Medicines Agency (EMA) have approved several medicinal products containing natural cannabinoids or their synthetic derivatives for the treatment of drug-resistant epilepsy, nausea and vomiting associated with cancer chemotherapy, anorexia in AIDS patients, and the alleviation of symptoms in patients with multiple sclerosis. In fact, cannabinoids constitute a broad group of molecules with a possible therapeutic potential that could be used in the management of much more diseases than mentioned above; therefore, multiple preclinical and clinical studies on cannabinoids have been carried out in recent years. Danio rerio (zebrafish) is an animal model that has gained more attention lately due to its numerous advantages, including easy and fast reproduction, the significant similarity of the zebrafish genome to the human one, simplicity of genetic modifications, and body transparency during the early stages of development. A number of studies have confirmed the usefulness of this model in toxicological research, experiments related to the impact of early life exposure to xenobiotics, modeling various diseases, and screening tests to detect active substances with promising biological activity. The present paper focuses on the current knowledge of the endocannabinoid system in the zebrafish model, and it summarizes the results and observations from studies investigating the pharmacological effects of natural and synthetic cannabinoids that were carried out in Danio rerio. The presented data support the notion that the zebrafish model is a suitable animal model for use in cannabinoid research.
... Rimonabant, a well-known CB1 antagonist has been shown to attenuate renal diseases such as CIH-induced kidney disease and renal fibrosis [29,81]. This antagonist was sold on the market in the past, as it was used to achieve weight-loss and was being tested as a cardiovascular drug [107,108]. However, due to the inhibitory effects of the drug in the CNS, rimonabant began to show psychiatric side effects of anxiety and depression [109,110]. ...
Endocannabinoid signaling plays crucial roles in human physiology in the function of multiple systems. The two cannabinoid receptors, CB1 and CB2, are cell membrane proteins that interact with both exogenous and endogenous bioactive lipid ligands, or endocannabinoids. Recent evidence has established that endocannabinoid signaling operates within the human kidney, as well as suggests the important role it plays in multiple renal pathologies. CB1, specifically, has been identified as the more prominent ECS receptor within the kidney, allowing us to place emphasis on this receptor. The activity of CB1 has been repeatedly shown to contribute to both diabetic and non-diabetic chronic kidney disease (CKD). Interestingly, recent reports of acute kidney injury (AKI) have been attributed to synthetic cannabinoid use. Therefore, the exploration of the ECS, its receptors, and its ligands can help provide better insight into new methods of treatment for a range of renal diseases. This review explores the endocannabinoid system, with a focus on its impacts within the healthy and diseased kidney.
... The cannabis oil administration presented reduction in these enzymes in serum and liver, together with an improvement in the hepatic content of triglyceride and cholesterol, suggesting a significant decrease in steatosis and liver damage, showing the hepatoprotective effect of cannabis oil used in present study. In this line, some studies suggest that the cannabinoids Δ9-THC and/or CBD increase HDL-C concentration, reduce total cholesterol and triglyceride in serum and decreases hepatic triglyceride accumulation and liver damage in other animal models [32][33][34][35]. Although none of them were performed in male Wistar rats fed with a SRD. ...
Objective: The aim of the present study was to analyse the effects of cannabis oil on cannabinoid-induced tetrad, blood pressure, and metabolic parameters in rats normal fed a sucrose-rich diet (SRD). Methods: Male Wistar rats were fed the following diets for 21 days: Reference Diet (RD): standard commercial laboratory diet, SRD and SRD+Cannabis oil (SRD+Ca): the oral administration of 1 mg/kg of body weight of cannabis oil daily. Cannabis oil present a total cannabinoids CBD:THC 2:1 ratio. During the experimental period, body weight, food intake, blood pressure, body temperature, locomotion, catalepsy and analgesia were evaluated. At the end of the experimental period, levels of glucose, triglycerides, cholesterol, uric acid, AST, ALT and AP in serum were evaluated. In liver were determined AST, ALT and AP enzymes and triglycerides and cholesterol content. Results: A cannabis oil administration significantly increased (P<0.05) analgesia, and locomotion was also significantly decreased, which was found to be increased in the SRD group. Systolic and diastolic blood pressure decreased during the experiment. In the SRD+Ca group, serum triglycerides and cholesterol levels significantly decreased, reaching values similar to RD group, without changes in glucose levels. In addition, serum uric acid and AP levels significantly decreased, although did not obtain reference values. AST and ALT levels in serum and liver significantly decreased, reaching reference values. At the liver, the triglycerides and cholesterol content significantly decreased with the administration of cannabis oil, although not reaching to reference values. Conclusions: Our results suggest that cannabis oil could be useful as a therapeutic strategy to prevent some of the alterations present in Metabolic Syndrome, including hypertension, dyslipidemia and liver damage. In addition, the analgesic effect of cannabis oil could be observed in SRD-fed rats.
... The endocannabinoid system (ECS) is an integral component of body homeostasis responsible for the regulation of numerous physiological processes, including energy metabolism, immune response, motor activity and pain perception (Silvestri & Di Marzo, 2013). The first studies on this system were reported in 1992 with the discovery of endogenous molecule-N-arachidonoylethanolamide (anadamide, AEA) in pork brain samples (Devane et al., 1992). ...
Introduction
The endocannabinoid system consists of different types of receptors, enzymes and endocannabinoids (ECs), which are involved in several physiological processes, but also play important role in the development and progression of central nervous system disorders.
Objectives
The purpose of this study was to apply precise and sensitive methodology for monitoring of four ECs, namely anandamide (AEA), 2-arachidonoyl glycerol (2-AG), N-arachidonoyl dopamine (NADA), 2-arachidonyl glyceryl ether (2-AGe) in selected brain regions of female and male rats at different stages of development (young, adult and old).
Methods
Biocompatible solid-phase microextraction (SPME) probes were introduced into the intact (non-homogenized) brain structures for isolation of four ECs, and the extracts were subjected to LC–MS/MS analysis. Two chemometric approaches, namely hierarchical cluster analysis (HCA) and Principal Component Analysis (PCA) were applied to provide more information about the levels of 2-AG and AEA in different brain structures.
Results
2-AG and AEA were extracted and could be quantified in each brain region; the level of 2-AG was significantly higher in comparison to the level of AEA. Two highly unstable ECs, NADA and 2-AGe, were captured by SPME probes from intact brain samples for the first time.
Conclusion
SPME probes were able to isolate highly unstable endogenous compounds from intact tissue, and provided new tools for precise analysis of the level and distribution of ECs in different brain regions. Monitoring of ECs in brain samples is important not only in physiological conditions, but also may contribute to better understanding of the functioning of the endocannabinoid system in various disorders.
... Moreover, obesity has been associated with dynamic changes in ECS: individuals with obesity show an increase of the endocannabinoid tone and an overactivation of the ECS (Monteleone et al., 2016;Silvestri & Di Marzo, 2013). Furthermore, clinical and preclinical observations reported that obesity is linked to polymorphisms of genes involved in the ECS (Pucci et al., 2021;Rossi et al., 2018) and that individuals with obesity present altered expression of proteins of ECS both in peripheral tissues (Cocci et al., 2021;Ruiz de Azua & Lutz, 2019) and in the brain (Pucci et al., 2019). ...
Objective:
Consumption of energy-dense palatable "comfort" food can alleviate stress and negative emotions, while abrupt withdrawal from a palatable diet can worsen these symptoms, causing difficulties with adherence to weight-loss diets. Currently, no pharmacological treatment is effective for obesity-related anxiety, so we investigated the endocannabinoid system (ECS), and specifically the fatty acid amide hydrolase (FAAH), as an interesting emerging target in this context because of its key role in the regulation of both energy homeostasis and emotional behavior.
Methods:
Rats were subjected to exposure and subsequent abstinence from a palatable cafeteria diet. During abstinence period, rats were treated with the selective FAAH inhibitor PF-3845 (10 mg/kg; intraperitoneal administration every other day).
Results:
Abstinent rats displayed an anxiogenic-like behavior and changes in the proteins of ECS signaling machinery in brain areas involved both in anxiety and food intake regulation. In particular, withdrawal caused a reduction of the expression of cannabinoid receptors in the nucleus accumbens and of enzymes diacylglycerol lipase alpha and monoacylglycerol lipase (MAGL) in the amygdala. Pharmacological inhibition of FAAH exerted an anxiolytic-like effect in abstinent animals and increased both MAGL expression in amygdala and CB2 expression in prefrontal cortex.
Discussion:
Overall, our results suggest that emotional disturbances associated with dieting are coupled with region-specific alterations in the cerebral expression of the ECS and that the enhancement of the endocannabinoid signaling by FAAH inhibition might represent a novel pharmacological strategy for the treatment of anxiety related to abstinence from palatable food.
Public significance:
The present study focused on evaluating the role of the endocannabinoid system in modulating withdrawal from naturally rewarding activities that have an impact on mood, such as feeding. The variations observed in the emotional behavior of abstinent rats was linked to neuroadaptations of the ECS in specific brain areas.
... Previous pre-clinical and clinical studies clearly demonstrated that the endocannabinoid system plays a pivotal role in energy metabolism homeostasis. It has been reported that tissue and circulating concentrations of some endocannabinoid species derived from the ω-6 PUFA AA -such as AEA and 2-AG -are increased, while ω-3 PUFA-containing NAEs and MAGs are decreased, under pathophysiological conditions63 . In the present study, both models of ω-3 PUFA-tissue enrichment significantly modulated the liver endocannabinoidome compared to HF diet alone, rich in precursors for 6 PUFA. ...
We compared endogenous ω-3 PUFA production to supplementation for improving obesity-related metabolic dysfunction. Fat-1 transgenic mice, who endogenously convert exogenous ω-6 to ω-3 PUFA, and wild-type littermates were fed a high-fat diet and a daily dose of either ω-3 or ω-6 PUFA-rich oil for 12 wk. The endogenous ω-3 PUFA production improved glucose intolerance and insulin resistance but not hepatic steatosis. Conversely, ω-3 PUFA supplementation fully prevented hepatic steatosis but failed to improve insulin resistance. Both models increased hepatic levels of ω-3 PUFA-containing 2-monoacylglycerol and N-acylethanolamine congeners, and reduced levels of ω-6 PUFA-derived endocannabinoids with ω-3 PUFA supplementation being more efficacious. Reduced hepatic lipid accumulation associated with the endocannabinoidome metabolites EPEA and DHEA, which was causally demonstrated by lower lipid accumulation in oleic acid-treated hepatic cells treated with these metabolites. While both models induced a significant fecal enrichment of the beneficial Allobaculum genus, mice supplemented with ω-3 PUFA displayed additional changes in the gut microbiota functions with a significant reduction of fecal levels of the proinflammatory molecules lipopolysaccharide and flagellin. Multiple-factor analysis identify that the metabolic improvements induced by ω-3 PUFAs were accompanied by a reduced production of the proinflammatory cytokine TNFα, and that ω-3 PUFA supplementation had a stronger effect on improving the hepatic fatty acid profile than endogenous ω-3 PUFA. While endogenous ω-3 PUFA production preferably improves glucose tolerance and insulin resistance, ω-3 PUFA intake appears to be required to elicit selective changes in hepatic endocannabinoidome signaling that are essential to alleviate high-fat diet-induced hepatic steatosis.
... Cannabidiol has an experimental [24,[342][343][344][345] and an epidemiological literature describing its genotoxic effects in both cancer [112][113][114] and congenital anomalies [103]. Cannabidiol is also genotoxic by virtue of its involvement in signaling via the nuclear receptor-transcription factor PPARγ (Peroxisome proliferator receptor gamma) [346][347][348][349][350][351][352][353], by its inhibition of mitochondrial respiration which forms the energetic and co-factor substrate basis for the epigenomic machinery [41,42,[354][355][356][357][358][359][360][361], and by its interaction at higher doses [362][363][364][365][366][367][368][369][370] with the cannabinoid type 1 receptors present on mitochondria themselves [44,[145][146][147][371][372][373][374]. Importantly, the PPARγ nuclear signal is transduced by binding to retinoic acid receptors (RXR) which together then bind the genome [375]. ...
Background:
Twelve separate streams of empirical data make a strong case for cannabis-induced accelerated aging including hormonal, mitochondriopathic, cardiovascular, hepatotoxic, immunological, genotoxic, epigenotoxic, disruption of chromosomal physiology, congenital anomalies, cancers including inheritable tumorigenesis, telomerase inhibition and elevated mortality.
Methods:
Results from a recently published longitudinal epigenomic screen were analyzed with regard to the results of recent large epidemiological studies of the causal impacts of cannabis. We also integrate theoretical syntheses with prior studies into these combined epigenomic and epidemiological results.
Results:
Cannabis dependence not only recapitulates many of the key features of aging, but is characterized by both age-defining and age-generating illnesses including immunomodulation, hepatic inflammation, many psychiatric syndromes with a neuroinflammatory basis, genotoxicity and epigenotoxicity. DNA breaks, chromosomal breakage-fusion-bridge morphologies and likely cycles, and altered intergenerational DNA methylation and disruption of both the histone and tubulin codes in the context of increased clinical congenital anomalies, cancers and heritable tumors imply widespread disruption of the genome and epigenome. Modern epigenomic clocks indicate that, in cannabis-dependent patients, cannabis advances cellular DNA methylation age by 25-30% at age 30 years. Data have implications not only for somatic but also stem cell and germ line tissues including post-fertilization zygotes. This effect is likely increases with the square of chronological age.
Conclusion:
Recent epigenomic studies of cannabis exposure provide many explanations for the broad spectrum of cannabis-related teratogenicity and carcinogenicity and appear to account for many epidemiologically observed findings. Further research is indicated on the role of cannabinoids in the aging process both developmentally and longitudinally, from stem cell to germ cell to blastocystoids to embryoid bodies and beyond.
... A better understanding of the biological mechanisms that control appetite and energy utilization, considering sexual dimorphism in energy and substrate metabolism, is needed to design more effective interventions for the prevention and management of obesity-related metabolic diseases (7)(8)(9). The endogenous cannabinoid system, (that is, the endocannabinoid system), is an ubiquitous lipid signaling system that has a critical role in obesity and metabolic syndrome (10). Endocannabinoids (eCBs), the lipid messengers of this neuromodulatory system, are produced on-demand by cell membrane phospholipids in the brain, where they stimulate hunger by modulation of synaptic transmission (11,12), but also in peripheral tissues, including adipose tissue, liver, pancreas, skeletal muscle and gut, where they control lipid and glucose metabolism (13)(14)(15). ...
Background
Excess circulating endocannabinoids (eCBs) and imbalanced N -acylethanolamines (NAEs) related eCBs abundance could influence dietary weight loss success. We aimed to examine sex differences in the impact of a 3-years Mediterranean diet (MedDiet) intervention on circulating eCBs, NAEs and their precursor fatty acids, and to analyze the interplay between changes in eCBs or NAEs ratios, insulin resistance and the achievement of clinically meaningful weight reductions.
Methods
Prospective cohort study in a subsample of N = 105 participants (54.3% women; 65.6 ± 4.6 years) with overweight or obesity and metabolic syndrome that underwent a 3-years MedDiet intervention (PREDIMED-Plus study). Plasma eCBs and NAEs, including 2-arachidonoylglycerol (2-AG), anandamide (AEA), oleoylethanolamide (OEA) and palmitoylethanolamide (PEA), fatty acids, diet, glycemic homeostasis (including the assessment of insulin resistance-HOMA-IR), and cardiovascular risk markers were monitored (at 0-6-12-36 months).
Results
Mediterranean diet adherence increased in both sexes and remained high during the 3 years of follow-up. Reductions in body weight, glycemic and cardiovascular parameters were larger in men than in women. Women presented higher concentrations of NAEs than men throughout the study. In both sexes, AEA and other NAEs (including OEA, and PEA) decreased after 6 months (for AEA: −4.9%), whereas the ratio OEA/AEA increased after 1 year (+5.8%). Changes in 2-AG (−3.9%) and the ratio OEA/PEA (+8.2%) persisted over the 3 years of follow-up. In women, 6-months changes in AEA (OR = 0.65) and the ratio OEA/AEA (OR = 3.28) were associated with the achievement of 8% weight reductions and correlated with HOMA-IR changes ( r = 0.29 and r = −0.34). In men, OEA/PEA changes were associated with 8% weight reductions (OR = 2.62) and correlated with HOMA-IR changes ( r = −0.32).
Conclusion
A 3-years MedDiet intervention modulated plasma concentrations of eCBs and NAEs. Changes in AEA and in the relative abundance of NAEs were associated with clinically meaningful weight reductions. However, marked sex differences were identified in eCBs and NAEs, as well as in the efficacy of the intervention in terms of glycemic and cardiovascular parameters, which could be related to post-menopause alterations in glucose metabolism. These findings support a sex-balanced research strategy for a better understanding of the mechanisms underlying the regulation of body weight loss.
... [19][20][21] The homeostatic process of food intake includes the hyperphagic and hypophagic effects of endocannabinoids that have GABAergic and glutamatergic effects, as well as additional neurochemical processes. 22 The close relationship between circadian control of food intake and clock genes has been shown in animal studies. It has been illustrated that there is a decrease in day-night variation in the food intake pattern of mice with a global deletion in the clock gene, and there is a change in the daily fasting-feeding cycles in general. ...
A circadian rhythm is a 24-hour rhythm controlled by a master clock, the suprachiasmatic nucleus, and driven by synchronizing internal/external zeitgebers. Food intake is one of the most important external cues/zeitgebers. Studies in humans and animals have shown that misalignment of food intake leads to chronodisruption, which is associated with metabolic disruption, obesity, and disordered eating attitudes. The term chronotype, which expresses the circadian typology, has been classified into 3 main types that represent the differences in the reflection of circadian rhythms shown in human studies on daily behaviors. It has been reported that evening-type individuals are more prone to disrupted eating attitudes, such as skipping meals, eating at night, and consuming a calorie-rich diet. In addition, eating disorders up to the diagnostic level is associated with the evening type. The bidirectional relationship between impaired circadian rhythms and disordered eating attitudes has brought chronotherapeutic interventions, which are biological rhythm-oriented treatment approaches, to the agenda. Bright light therapy has been found to reduce bulimic eating behaviors and night eating symptoms. More evidence is needed regarding the effect of chronotherapeutic approaches on metabolic disorders, disordered eating attitudes, and eating disorders associated with obesity.
... Endocannabinoids are long chain w-6 polyunsaturated fatty acid (PUFA)-derived lipid mediators and include anandamide (AEA) and 2-arachidonoyl-glycerol (2-AG), mostly acting at G proteincoupled cannabinoid type 1 and type 2 (CB 1 and CB 2 ) receptors. Their respective congeners, the N-acyl-ethanolamines (NAEs) and 2-monoacyl-glycerols (2-MAGs), respectively, are important components of the eCBome, and, with the two eCBs, are involved in multiple physiological processes (36,37). The recognized functions of eCBs include the regulation of satiety, energy control and lipid metabolism through the CB 1 receptor, increasing food intake, reducing energy expenditure, and promoting fat accumulation in adipose tissue (38, 39). ...
Dietary micronutrients act at the intestinal level, thereby influencing microbial communities, the host endocannabinoidome, and immune and anti-oxidative response. Selenium (Se) is a trace element with several health benefits. Indeed, Se plays an important role in the regulation of enzymes with antioxidative and anti-inflammatory activity as well as indicators of the level of oxidative stress, which, together with chronic low-grade inflammation, is associated to obesity. To understand how Se variations affect diet-related metabolic health, we fed female and male mice for 28 days with Se-depleted or Se-enriched diets combined with low- and high-fat/sucrose diets. We quantified the plasma and intestinal endocannabinoidome, profiled the gut microbiota, and measured intestinal gene expression related to the immune and the antioxidant responses in the intestinal microenvironment. Overall, we show that intestinal segment-specific microbiota alterations occur following high-fat or low-fat diets enriched or depleted in Se, concomitantly with modifications of circulating endocannabinoidome mediators and changes in cytokine and antioxidant enzyme expression. Specifically, Se enrichment was associated with increased circulating plasma levels of 2-docosahexaenoyl-glycerol (2-DHG), a mediator with putative beneficial actions on metabolism and inflammation. Others eCBome mediators also responded to the diets. Concomitantly, changes in gut microbiota were observed in Se-enriched diets following a high-fat diet, including an increase in the relative abundance of Peptostreptococcaceae and Lactobacillaceae. With respect to the intestinal immune response and anti-oxidative gene expression, we observed a decrease in the expression of proinflammatory genes Il1β and Tnfα in high-fat Se-enriched diets in caecum, while in ileum an increase in the expression levels of the antioxidant gene Gpx4 was observed following Se depletion. The sex of the animal influenced the response to the diet of both the gut microbiota and endocannabinoid mediators. These results identify Se as a regulator of the gut microbiome and endocannabinoidome in conjunction with high-fat diet, and might be relevant to the development of new nutritional strategies to improve metabolic health and chronic low-grade inflammation associated to metabolic disorders.
... Endocannabinoids, their synthesizing and metabolizing enzymes, and their receptors constitute the endocannabinoid system (ECS). It has been revealed that the overactivation of cannabinoid receptors type 1 (CB1) has a significant role in lipogenesis, hepatic steatosis, obesity, and insulin resistance [11][12][13]. The CB1 receptor is found in CNS and in peripheral organs which control metabolism and activates anabolic pathways in favor of energy storage [14]. ...
Background
The role of the Endocannabinoids (ECs) in insulin resistance, and their association with visceral obesity and metabolic profile have been studied extensively. Since the association between ECs and metabolic factors in Gestational Diabetes Mellitus (GDM) are not clear, we aimed to evaluate the levels of N-Arachidonoylethanolamide (AEA) and 2-Arachidonoylglycerol (2-AG) and their association with C-reactive protein (CRP), glycemic indices, blood pressure, and anthropometric indices in pregnant women with GDM.
Methods
The present case–control study was conducted among 96 singleton pregnant women aged 18–40 years, including 48 healthy pregnant women (control group) and 48 women with a positive diagnosis of GDM (case group). Odds Ratios (ORs) and 95% Confidence Intervals (CIs) for GDM were checked according to endocannabinoids and anthropometric indices using Multivariable Logistic Regression.
Results
AEA was significantly associated with increased risk of GDM in models 1, 2 and 3 (OR = 1.22, 95% CI: 1.06–1.41; OR = 1.54, 95% CI: 1.19–1.97; OR = 1.46, 95% CI:1.11–1.91). A positive but no significant association was found for AEA in model 4 (OR = 1.38,95% CI: 0.99–1.92). Similar to AEA, 2-AG was also positively associated with the likelihood of GDM in Models 1, 2, and 3 but the association attenuated to null in model 4 (OR = 1.25; 95% CI: 0.94- 1.65).
Conclusions
Our findings showed that levels of ECs were significantly higher in pregnant women with GDM compared to healthy ones. Also, ECs levels were associated with the likelihood of GDM, independent of BMI and weight gain.
... The endocannabinoid system (ECS) is a central regulator of metabolism and energy homeostasis (Silvestri and Di Marzo, 2013), that is also involved in immune modulation in mammals. The ECS components are the ligands, receptors, and enzymes that synthesize and degrade the endogenous ligands of the ECS, called endocannabinoids (eCBs). ...
... Although important molecular effects of eCBs in skeletal muscle have been identified [53], so far it is not known if they engage the regulation of mitochondrial activity, which is essential for skeletal muscle metabolism and proper tissue plasticity. It should be recalled that AEA is known to play a key role in energy homeostasis [37][38][39], and indeed it can affect the shape and function of isolated mitochondria [42]. In line with this, some reports have even suggested a mitochondrial localization of CB 1 , supporting the view that AEA-dependent effects on energy production are triggered by these particular CB 1 receptors [61,62]. ...
The sphingosine 1-phosphate (S1P) and endocannabinoid (ECS) systems comprehend bioactive lipids widely involved in the regulation of similar biological processes. Interactions between S1P and ECS have not been so far investigated in skeletal muscle, where both systems are active. Here, we used murine C2C12 myoblasts to investigate the effects of S1P on ECS elements by qRT-PCR, Western blotting and UHPLC-MS. In addition, the modulation of the mitochondrial membrane potential (ΔΨm), by JC-1 and Mitotracker Red CMX-Ros fluorescent dyes, as well as levels of protein controlling mitochondrial function, along with the oxygen consumption were assessed, by Western blotting and respirometry, respectively, after cell treatment with methanandamide (mAEA) and in the presence of S1P or antagonists to endocannabinoid-binding receptors. S1P induced a significant increase in TRPV1 expression both at mRNA and protein level, while it reduced the protein content of CB2. A dose-dependent effect of mAEA on ΔΨm, mediated by TRPV1, was evidenced; in particular, low doses were responsible for increased ΔΨm, whereas a high dose negatively modulated ΔΨm and cell survival. Moreover, mAEA-induced hyperpolarization was counteracted by S1P. These findings open new dimension to S1P and endocannabinoids cross-talk in skeletal muscle, identifying TRPV1 as a pivotal target.
... Both CB1R and CB2R have also been found in other organs and tissues, where they regulate, among other things, hormone secretion, blood circulation, gastrointestinal-tract functions, reproductive-system functions, and energy metabolism [16,17]. There is a growing body of literature supporting the implication of the eCBS in the regulation of hepatic lipid and glucose metabolisms [18,19] and the modulation of the immunological response at the hepatic site, and particularly in the establishment and regulation of liver inflammation [20,21]. Additionally, it has been shown that hepatic CB1R and CB2R have dual and opposite effects on fibrogenesis associated with chronic liver injury: CB1R promotes profibrogenic effects, while CB2R elicits antifibrogenic effects [22,23]. ...
Nonalcoholic fatty liver disease (NAFLD), alcohol-induced liver disease (ALD), and viral hepatitis are the main causes of morbidity and mortality related to chronic liver diseases (CLDs) worldwide. New therapeutic approaches to prevent or reverse these liver disorders are thus emerging. Although their etiologies differ, these CLDs all have in common a significant dysregulation of liver metabolism that is closely linked to the perturbation of the hepatic endocannabinoid system (eCBS) and inflammatory pathways. Therefore, targeting the hepatic eCBS might have promising therapeutic potential to overcome CLDs. Experimental models of CLDs and observational studies in humans suggest that cannabis and its derivatives may exert hepatoprotective effects against CLDs through diverse pathways. However, these promising therapeutic benefits are not yet fully validated, as the few completed clinical trials on phytocannabinoids, which are thought to hold the most promising therapeutic potential (cannabidiol or tetrahydrocannabivarin), remained inconclusive. Therefore, expanding research on less studied phytocannabinoids and their derivatives, with a focus on their mode of action on liver metabolism, might provide promising advances in the development of new and original therapeutics for the management of CLDs, such as NAFLD, ALD, or even hepatitis C-induced liver disorders.
Background
The metabolic changes that ultimately lead to gestational diabetes mellitus (GDM) likely begin before pregnancy. Cannabis use might increase the risk of GDM by increasing appetite or promoting fat deposition and adipogenesis.
Objectives
We aimed to assess the association between preconception cannabis use and GDM incidence.
Methods
We analysed individual‐level data from eight prospective cohort studies. We identified the first, or index, pregnancy (lasting ≥20 weeks of gestation with GDM status) after cannabis use. In analyses of pooled individual‐level data, we used logistic regression to estimate study‐type‐specific odds ratios (OR) and 95% confidence intervals (CI), adjusting for potential confounders using random effect meta‐analysis to combine study‐type‐specific ORs and 95% CIs. Stratified analyses assessed potential effect modification by preconception tobacco use and pre‐pregnancy body mass index (BMI).
Results
Of 17,880 participants with an index pregnancy, 1198 (6.7%) were diagnosed with GDM. Before the index pregnancy, 12.5% of participants used cannabis in the past year. Overall, there was no association between preconception cannabis use in the past year and GDM (OR 0.97, 95% CI 0.79, 1.18). Among participants who never used tobacco, however, those who used cannabis more than weekly had a higher risk of developing GDM than those who did not use cannabis in the past year (OR 2.65, 95% CI 1.15, 6.09). This association was not present among former or current tobacco users. Results were similar across all preconception BMI groups.
Conclusions
In this pooled analysis of preconception cohort studies, preconception cannabis use was associated with a higher risk of developing GDM among individuals who never used tobacco but not among individuals who formerly or currently used tobacco. Future studies with more detailed measurements are needed to investigate the influence of preconception cannabis use on pregnancy complications.
We have designed orally bioavailable, non-brain-penetrant antagonists of the cannabinoid-1 receptor (CB1R) with a built-in biguanide sensor to mimic 5'-adenosine monophosphate kinase (AMPK) activation for treating obesity-associated co-morbidities. A series of 3,4-diarylpyrazolines bearing rational pharmacophoric pendants designed to limit brain penetration were synthesized and evaluated in CB1R ligand binding assays and recombinant AMPK assays. The compounds displayed high CB1R binding affinity and potent CB1R antagonist activities and acted as AMPK activators. Select compounds showed good oral exposure, with compounds 36, 38-S, and 39-S showing <5% brain penetrance, attesting to peripheral restriction. In vivo studies of 38-S revealed decreased food intake and body weight reduction in diet-induced obese mice as well as oral in vivo efficacy of 38-S in ameliorating glucose tolerance and insulin resistance. The designed "cannabinoformin" four-arm CB1R antagonists could serve as potential leads for treatment of metabolic syndrome disorders with negligible neuropsychiatric side effects.
Cannabinoids (CBDs) represent a group of C21 or C22 terpenophenolic compounds predominantly produced by Cannabis but have also been found in plants from the Radula and Helichrysum genera. There are about 100 different cannabinoids, although some of them are metabolites. They are generally classified into ten subclasses [1–3].
The brain requires large quantities of energy to sustain its functions. At the same time, the brain is isolated from the rest of the body, forcing this organ to develop strategies to control and fulfill its own energy needs. Likely based on these constraints, several brain-specific mechanisms emerged during evolution. For example, metabolically specialized cells are present in the brain, where intercellular metabolic cycles are organized to separate workload and optimize the use of energy. To orchestrate these strategies across time and space, several signaling pathways control the metabolism of brain cells. One of such controlling systems is the endocannabinoid system, whose main signaling hub in the brain is the type-1 cannabinoid (CB1 ) receptor. CB1 receptors govern a plethora of different processes in the brain, including cognitive function, emotional responses, or feeding behaviors. Classically, the mechanisms of action of CB1 receptors on brain function had been explained by its direct targeting of neuronal synaptic function. However, new discoveries have challenged this view. In this review, we will present and discuss recent data about how a small fraction of CB1 receptors associated to mitochondrial membranes (mtCB1 ), are able to exert a powerful control on brain functions and behavior. mtCB1 receptors impair mitochondrial functions both in neurons and astrocytes. In the latter cells, this effect is linked to an impairment of astrocyte glycolytic function, resulting in specific behavioral outputs. Finally, we will discuss the potential implications of (mt)CB1 expression on oligodendrocytes and microglia metabolic functions, with the aim to encourage interdisciplinary approaches to better understand the role of (mt)CB1 receptors in brain function and behavior.
Cannabidiol (CBD) is a non-intoxicating cannabinoid extracted from the cannabis plant that is used for medicinal purposes. Ingestion of CBD is claimed to address several pathologies, including gastrointestinal disorders, although limited evidence has been generated thus far to substantiate many of its health claims. Nevertheless, CBD usage as an over-the-counter treatment for gastrointestinal disorders is likely to expand in response to increasing commercial availability, permissive legal status, and acceptance by consumers. This systematic review critically evaluates the knowledge boundaries of the published research on CBD, intestinal motility, and intestinal motility disorders. Research on CBD and intestinal motility is currently limited but does support the safety and efficacy of CBD for several therapeutic applications, including seizure disorders, inflammatory responses, and upper gastrointestinal dysfunction (i.e., nausea and vomiting). CBD, therefore, may have therapeutic potential for addressing functional gastrointestinal disorders. The results of this review show promising in vitro and preclinical data supporting a role of CBD in intestinal motility. This includes improved gastrointestinal-related outcomes in murine models of colitis. These studies, however, vary by dose, delivery method, and CBD-extract composition. Clinical trials have yet to find a conclusive benefit of CBD on intestinal motility disorders, but these trials have been limited in scope. In addition, critical factors such as CBD dosing parameters have not yet been established. Further research will establish the efficacy of CBD in applications to address intestinal motility.
The endocannabinoid system (ECS), particularly its signaling pathways and ligands, has garnered considerable interest in recent years. Along with clinical work investigating the ECS’ functions, including its role in the development of neurological and inflammatory conditions, much research has focused on developing analytical protocols enabling the precise monitoring of the levels and metabolism of the most potent ECS ligands: exogenous phytocannabinoids (PCs) and endogenous cannabinoids (endocannabinoids, ECs). Solid-phase microextraction (SPME) is an advanced, non-exhaustive sample-preparation technique that facilitates the precise and efficient isolation of trace amounts of analytes, thus making it appealing for the analysis of PCs and ECs in complex matrices of plant and animal/human origin. In this paper, we review recent forensic medicine and toxicological studies wherein SPME has been applied to monitor levels of PCs and ECs in complex matrices, determine their effects on organism physiology, and assess their role in the development of several diseases.
Among the sources of chemical signals regulating food intake, energy metabolism and body weight, few have attracted recently as much attention as the expanded endocannabinoid system, or endocannabinoidome (eCBome), and the gut microbiome, the two systems on which this review article is focussed. Therefore, it is legitimate to expect that these two systems also play a major role in the etiopathology of eating disorders (EDs), in particular of anorexia nervosa, bulimia nervosa and binge-eating disorder. The major mechanisms through which, also via interactions with other endogenous signaling systems, the eCBome, with its several lipid mediators and receptors, and the gut microbiome, via its variety of microbial kingdoms, phyla and species, and armamentarium of metabolites, intervene in these disorders, are described here, based on several published studies in either experimental models or patients. Additionally, in view of the emerging multi-faceted cross-talk mechanisms between these two complex systems, we discuss the possibility that the eCBome-gut microbiome axis is also involved in EDs.
Objetivo: Descrever e apresentar a importância do Cannabidiol no uso terapêutico na doença de Alzheimer (DA). Revisão bibliográfica: A DA é a forma mais comum de demência, está entre as doenças incuráveis e é classificada como neurodegenerativa. Patologia que se dá início quando algumas proteínas se instalam no sistema nervoso central e começam a desenvolver atividades fisiológicas de forma inapropriada ocorrendo a perda progressiva de neurônios em algumas regiões do cérebro. O uso terapêutico do cannabidiol no tratamento da DA, tem eficácia como um agente neuro protetor, anti-inflamatório e antioxidante, adiando o efeito gradual da doença. As doses do Cannabidiol Fitocanabinóide (CDB) reduzem o acúmulo de uma proteína no cérebro chamada beta-amiloide, que é o principal culpado pelo surgimento do Alzheimer, visto que esta proteína afeta as sinapses e sinalizam para as células da inflamação do neurônio, fazendo com que essas células sejam destruídas. Considerações finais: De acordo com pesquisas realizadas sobre a atuação do cannabidiol em doenças do Sistema Nervoso Central (SNC) o CBD tem a capacidade de diminuir os sintomas do DA.
Objective:
Orexin-A (OX-A) is a neuropeptide produced selectively by neurons of the lateral hypothalamus. It exerts powerful control over brain function and physiology by regulating energy homeostasis and complex behaviors linked to arousal. Under conditions of chronic or acute brain leptin signaling deficiency, such as in obesity or short-term food deprivation, respectively, OX-A neurons become hyperactive and promote hyperarousal and food seeking. However, this leptin-dependent mechanism is still mostly unexplored. The endocannabinoid 2-arachidonoyl-glycerol (2-AG) is known to be implicated in food consumption by promoting hyperphagia and obesity, and we and others demonstrated that OX-A is a strong inducer of 2-AG biosynthesis. Here, we investigated the hypothesis that, under acute (6 h fasting in wt mice) or chronic (in ob/ob mice) hypothalamic leptin signaling reduction, OX-A-induced enhancement of 2-AG levels leads to the production of the 2-AG-derived 2-arachidonoyl-sn-glycerol-3-phosphate (2-AGP), a bioactive lipid belonging to the class of lysophosphatidic acids (LPAs), which then regulates hypothalamic synaptic plasticity by disassembling α-MSH anorexigenic inputs via GSK-3β-mediated Tau phosphorylation, ultimately affecting food intake.
Methods:
We combined cell-type-specific morphological (CLEM and confocal microscopy), biochemical, pharmacological, and electrophysiological techniques to dissect the leptin- and OX-A/2-AGP-mediated molecular pathways regulating GSK-3β-controlled pT231-Tau production at POMC neurons of obese ob/ob and wild-type (wt) lean littermate mice and in an in vitro model of POMC neurons such as mHypoN41 neurons (N41).
Results:
2-AGP is overproduced in the hypothalamus of obese leptin-deficient, or lean 6 h food-deprived mice, and promotes food intake by reducing α-MSH-expressing synaptic inputs to OX-A neurons via lysophosphatidic acid type-1 receptor (LPA1-R) activation, and pT231-Tau accumulation in α-MSH projections. This effect is due to the activation of the Pyk2-mediated pTyr216-GSK3β pathway and contributes to further elevating OX-A release in obesity. Accordingly, we found a strong correlation between OX-A and 2-AGP levels in the serum of obese mice and of human subjects.
Conclusions:
Hypothalamic feeding pathways are endowed with 2-AGP-mediated synaptic plasticity according to their inherent functional activities and the necessity to adapt to changes in the nutritional status. These findings reveal a new molecular pathway involved in energy homeostasis regulation, which could be targeted to treat obesity and related disturbances.
The cannabinoid receptor CB1R is expressed in pancreatic β-cells; CB1R increased activity is associated with diabetes, obesity, cardiovascular disorders as well as decreased insulin secretion and insulin resistance. CB1R was shown to signal through G-protein coupling as well as β-arrestins in β-cells. Peripherally restricted CB1R inverse agonists purportedly have beneficial effects on insulin secretion in β-cells, without the unwanted effects in the central nervous system. Here we show that a peripherally restricted CB1R inverse agonist, MRI-1891, augments glucose stimulated insulin secretion in isolated human pancreatic islets and mouse islets. The insulin secretion enhancing effect of MRI-1891 is comparable to exendin-4, an analogue of the glucagon like peptide-1 (GLP1). Moreover, MRI-1891 treatment protects isolated human islet cells against cytokine-induced apoptosis, similar to exendin-4. Thus, MRI-1891, a new class of CB1R inverse agonist, may be considered a potential therapeutic for both type 1 and type 2 diabetes because of its ability to protect pancreatic β-cells from cytokine toxicity and to promote insulin secretion.
Transtorno do Espectro do Autismo | Trauma na Infância | Adição
Transtorno Do Estresse Pós-Traumático (TEPT) | Depressão | Esquizofrenia |Epilepsia
Dor Crônica | Zumbido | Estado Vegetativo e Outros Distúrbios de Consciência
Demência Do Tipo Alzheimer | Doença De Parkinson
Aspectos Neuropsiquiátricos Da Infecção Pelo HIV
Cannabis Sativa e Seus Derivados Naturais e Sintéticos: uso Terapêutico e Recreativo
Elisabete Castelon
Transtorno do Espectro do Autismo | Trauma na Infância | Adição
Transtorno Do Estresse Pós-Traumático (TEPT) | Depressão | Esquizofrenia |Epilepsia
Dor Crônica | Zumbido | Estado Vegetativo e Outros Distúrbios de Consciência
Demência Do Tipo Alzheimer | Doença De Parkinson
Aspectos Neuropsiquiátricos Da Infecção Pelo HIV
Cannabis Sativa e Seus Derivados Naturais e Sintéticos: uso Terapêutico e Recreativo
The use of cannabinoids as therapeutic drugs has increased among aging populations recently. Age-related changes in the endogenous cannabinoid system could influence the effects of therapies that target the cannabinoid system. At the preclinical level, cannabidiol (CBD) induces anti-amyloidogenic, antioxidative, anti-apoptotic, anti-inflammatory, and neuroprotective effects. These findings suggest a potential therapeutic role of cannabinoids to neurodegenerative disorders such as Parkinson’s disease (PD) and Alzheimer. Emerging evidence suggests that CBD and tetrahydrocannabinol have neuroprotective therapeutic-like effects on dementias. In clinical practice, cannabinoids are being used off-label to relieve symptoms of PD and AD. In fact, patients are using cannabis compounds for the treatment of tremor, non-motor symptoms, anxiety, and sleep assistance in PD, and managing responsive behaviors of dementia such as agitation. However, strong evidence from clinical trials is scarce for most indications. Some clinicians consider cannabinoids an alternative for older adults bearing Parkinson’s disease and Alzheimer’s dementia with a poor response to first-line treatments. In our concept and experience, cannabinoids should never be considered a first-line treatment but could be regarded as an adjuvant therapy in specific situations commonly seen in clinical practice. To mitigate the risk of adverse events, the traditional dogma of geriatric medicine, starting with a low dose and proceeding with a slow titration regime, should also be employed with cannabinoids. In this review, we aimed to address preclinical evidence of cannabinoids in neurodegenerative disorders such as PD and AD and discuss potential off-label use of cannabinoids in clinical practice of these disorders.
Endogenous and exogenous cannabinoids modulate many physiological and pathological processes by binding classical cannabinoid receptors 1 (CB1) or 2 (CB2) or non-cannabinoid receptors. Cannabinoids are known to exert antiproliferative, apoptotic, anti-migratory and anti-invasive effect on cancer cells by inducing or inhibiting various signaling cascades. In this chapter, we specifically emphasize the latest research works about the alterations in endocannabinoid system (ECS) components in malignancies and cancer cell proliferation, migration, invasion, angiogenesis, autophagy, and death by cannabinoid administration, emphasizing their mechanism of action, and give a future perspective for clinical use.
The endocannabinoid system (ECS) is an essential endogenous signaling system that may be involved in the pathophysiology of chronic widespread pain (CWP) and fibromyalgia syndrome (FMS). Further research is required to understand the role of ECS in the development and maintenance of CWP and FMS. We provided the first systematic review and meta-analysis exploring the clinical relevance of ECS alterations in patients with CWP and FMS by comparing plasma and interstitial levels of endocannabinoids and N-acylethanolamines in patients and healthy controls. A systematic search was conducted to identify studies that measured plasma and/or interstitial levels of endocannabinoids and N-acylethanolamines in patients with CWP or FMS and healthy controls. A total of 8 studies were included for qualitative review, and 7 studies were included for meta-analysis. The findings identified increased plasma levels of oleoylethanolamide and stearoylethanolamide in patients with FMS compared with those in controls (P 5 0.005 and P , 0.0001, respectively) and increased plasma levels of palmitoylethanolamide and interstitial levels of stearoylethanolamide in patients with CWP compared with those in controls (P 5 0.05 and P 5 0.001, respectively). There were no significant differences in other ECS parameters. Most studies did not account for variables that may influence ECS function, including cannabis use, concomitant medication, comorbidities, physical activity, stress levels, circadian rhythm, sleep quality, and dietary factors, suggesting that future studies should explore the correlation between these variables and endocannabinoid activity. We highlight the importance of investigating endocannabinoid activity in CWP and FMS because it will underpin future translational research in the area.
Obesity is a global public health problem linked to increased risk for many disorders including diabetes, cardiovascular disease, and even cancer. The World Health Organization estimates almost 2 billion adults worldwide are considered overweight with nearly 600 million of those individuals also being considered obese. How did we get here? The laws of thermodynamics would suggest it is simply a fact that we consume too many calories without burning an equal number, thus causing an imbalance that results in weight gain and eventual obesity. Such a situation would thus be easy to address, since simply reducing caloric intake would eliminate the problem. However, the story is far more complex and involves the interplay between both central and peripheral systems that regulate energy metabolism, energy consumption, and even the brain’s reward circuitry. This chapter explores the peripheral signals that not only contribute to obesity but also make it difficult for us to break the cycle that leads to metabolic dysregulation and obesity. We will specifically consider obesity in the context of the brain, which coordinates feeding, activity, circadian rhythms, and metabolic functions, while also being a target for many metabolic hormones. Thus, the state of being obese leads to changes not only in the periphery but also centrally within the brain. How this affects brain structure and function will also be discussed.
Cannabis plant has been used from ancient times with therapeutic purposes for treating human pathologies, but the identification of the cellular and molecular mechanisms underlying the therapeutic properties of the phytocannabinoids, the active compounds in this plant, occurred in the last years of the past century. In the late 1980s and early 1990s, seminal studies demonstrated the existence of cannabinoid receptors and other elements of the so-called endocannabinoid system. These G protein-coupled receptors (GPCRs) are a key element in the functions assigned to endocannabinoids and appear to serve as promising pharmacological targets. They include CB1, CB2, and GPR55, but also non-GPCRs can be activated by endocannabinoids, like ionotropic receptor TRPV1 and even nuclear receptors of the PPAR family. Their activation, inhibition, or simply modulation have been associated with numerous physiological effects at both central and peripheral levels, which may have therapeutic value in different human pathologies, then providing a solid experimental explanation for both the ancient medicinal uses of Cannabis plant and the recent advances in the development of cannabinoid-based specific therapies. This chapter will review the scientific knowledge generated in the last years around the research on the different endocannabinoid-binding receptors and their signaling mechanisms. Our intention is that this knowledge may help readers to understand the relevance of these receptors in health and disease conditions, as well as it may serve as the theoretical basis for the different experimental protocols to investigate these receptors and their signaling mechanisms that will be described in the following chapters.Key wordsCannabinoidsEndocannabinoid systemCB1 receptorCB2 receptorGPR55TRPV1 receptorPPARsCannabinoid-based therapies
Endocannabinoid lipids are known to exert orexigenic effects via central cannabinoid CB1 and CB2 receptors, which have also been identified in islet endocrine cells. However, there is no consensus on whether the receptors are expressed by β-cells, nor what effect CB1 and CB2 receptor agonists have on insulin secretion. In the current study we have therefore used the mouse MIN6 β-cell line rather than primary islets, which are heterogeneous clusters of endocrine cells. Cannabinoid receptor and diacylglycerol lipase isoform mRNAs were detected in MIN6 cells by RT-PCR and immunocytochemistry was used to identify cannabinoid receptor expression by MIN6 cells. Changes in cyclic AMP and intracellular calcium were measured by immunoassay and microfluorimetry, respectively, and insulin secretion from perifused MIN6 pseudoislets was determined by radioimmunoassay. MIN6 β-cells express the cannabinoid synthesising enzyme diacylglycerol lipase and CB1 and CB2 receptors, which are coupled to inhibition of β-cell cyclic AMP generation and stimulation of intracellular calcium levels. Cannabinoid receptor activation with pharmacological agonists resulted in reversible elevations in insulin secretion at both 2 mM and 20 mM glucose. Synthesis of endocannabinoids by β-cells may provide an additional mechanism for stimulation of insulin secretion through activation of β-cell CB1 and/or CB2 cannabinoid receptors.
The function of small intestinal monoacylglycerol lipase (MGL) is unknown. Its expression in this tissue is surprising because one of the primary functions of the small intestine is to convert diet-derived MGs to triacylglycerol (TG), and not to degrade them. To elucidate the function of intestinal MGL, we generated transgenic mice that over-express MGL specifically in small intestine (iMGL mice). After only 3 weeks of high fat feeding, iMGL mice showed an obese phenotype; body weight gain and body fat mass were markedly higher in iMGL mice, along with increased hepatic and plasma TG levels compared to wild type littermates. The iMGL mice were hyperphagic and displayed reduced energy expenditure despite unchanged lean body mass, suggesting that the increased adiposity was due to both increased caloric intake and systemic effects resulting in a hypometabolic rate. The presence of the transgene resulted in lower levels of most MG species in intestinal mucosa, including the endocannabinoid 2-arachidonoyl glycerol (2-AG). The results therefore suggest a role for intestinal MGL, and intestinal 2-AG and perhaps other MG species, in whole body energy balance via regulation of food intake as well as metabolic rate.
Insulin controls fatty acid (FA) release from white adipose tissue (WAT) through direct effects on adipocytes and indirectly through hypothalamic signaling by reducing sympathetic nervous system outflow to WAT. Uncontrolled FA release from WAT promotes lipotoxicity, which is characterized by inflammation and insulin resistance that leads to and worsens type 2 diabetes. Here we tested whether early diet-induced insulin resistance impairs the ability of hypothalamic insulin to regulate WAT lipolysis and thus contributes to adipose tissue dysfunction. To this end we fed male Sprague-Dawley rats a 10% lard diet (high fat diet (HFD)) for 3 consecutive days, which is known to induce systemic insulin resistance. Rats were studied by euglycemic pancreatic clamps and concomitant infusion of either insulin or vehicle into the mediobasal hypothalamus. Short term HFD feeding led to a 37% increase in caloric intake and elevated base-line free FAs and insulin levels compared with rats fed regular chow. Overfeeding did not impair insulin signaling in WAT, but it abolished the ability of mediobasal hypothalamus insulin to suppress WAT lipolysis and hepatic glucose production as assessed by glycerol and glucose flux. HFD feeding also increased hypothalamic levels of the endocannabinoid 2-arachidonoylglycerol after only 3 days. In summary, overfeeding impairs hypothalamic insulin action, which may contribute to unrestrained lipolysis seen in human obesity and type 2 diabetes.
Cannabinoid type 1 (CB(1)) receptor activation is generally considered a powerful orexigenic signal and inhibition of the endocannabinoid system is beneficial for the treatment of obesity and related metabolic diseases. The hypothalamus plays a critical role in regulating energy balance by modulating both food intake and energy expenditure. Although CB(1) receptor signaling has been implicated in the modulation of both these mechanisms, a complete understanding of its role in the hypothalamus is still lacking. Here we combined a genetic approach with the use of adeno-associated viral vectors to delete the CB(1) receptor gene in the adult mouse hypothalamus and assessed the impact of such manipulation on the regulation of energy balance. Viral-mediated deletion of the CB(1) receptor gene in the hypothalamus led to the generation of Hyp-CB(1)-KO mice, which displayed an approximately 60% decrease in hypothalamic CB(1) receptor mRNA levels. Hyp-CB(1)-KO mice maintained on a normocaloric, standard diet showed decreased body weight gain over time, which was associated with increased energy expenditure and elevated β(3)-adrenergic receptor and uncoupling protein-1 mRNA levels in the brown adipose tissue but, surprisingly, not to changes in food intake. Additionally, Hyp-CB(1)-KO mice were insensitive to the anorectic action of the hormone leptin (5 mg/kg) and displayed a time-dependent hypophagic response to the CB(1) inverse agonist rimonabant (3 mg/kg). Altogether these findings suggest that hypothalamic CB(1) receptor signaling is a key determinant of energy expenditure under basal conditions and reveal its specific role in conveying the effects of leptin and pharmacological CB1 receptor antagonism on food intake.
The goal of this study was to determine whether administration of the CB(1) cannabinoid receptor antagonist rimonabant would alter fatty acid flux in nonhuman primates. Five adult baboons (Papio Sp) aged 12.1 ± 4.7 yr (body weight: 31.9 ± 2.1 kg) underwent repeated metabolic tests to determine fatty acid and TG flux before and after 7 wk of treatment with rimonabant (15 mg/day). Animals were fed ad libitum diets, and stable isotopes were administered via diet (d(31)-tripalmitin) and intravenously ((13)C(4)-palmitate, (13)C(1)-acetate). Plasma was collected in the fed and fasted states, and blood lipids were analyzed by GC-MS. DEXA was used to assess body composition and a hyperinsulinemic euglycemic clamp used to assess insulin-mediated glucose disposal. During the study, no changes were observed in food intake, body weight, plasma, and tissue endocannabinoid concentrations or the quantity of liver-TG fatty acids originating from de novo lipogenesis (19 ± 6 vs. 16 ± 5%, for pre- and posttreatment, respectively, P = 0.39). However, waist circumference was significantly reduced 4% in the treated animals (P < 0.04), glucose disposal increased 30% (P = 0.03), and FFA turnover increased 37% (P = 0.02). The faster FFA flux was consistent with a 43% reduction in these fatty acids used for TRL-TG synthesis (40 ± 3 vs. 23 ± 4%, P = 0.02) and a twofold increase in TRL-TG turnover (1.5 ± 0.9 vs. 3.1 ± 1.4 μmol·kg(-1)·h(-1), P = 0.03). These data support the potential for a strong effect of CB(1) receptor antagonism at the level of adipose tissue, resulting in improvements in fasting turnover of fatty acids at the whole body level, central adipose storage, and significant improvements in glucose homeostasis.
n-3 polyunsaturated fatty acids, namely docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), reduce the risk of cardiovascular disease and can ameliorate many of obesity-associated disorders. We hypothesised that the latter effect will be more pronounced when DHA/EPA is supplemented as phospholipids rather than as triglycerides.
In a 'prevention study', C57BL/6J mice were fed for 9 weeks on either a corn oil-based high-fat obesogenic diet (cHF; lipids ∼35% wt/wt), or cHF-based diets in which corn oil was partially replaced by DHA/EPA, admixed either as phospholipids or triglycerides from marine fish. The reversal of obesity was studied in mice subjected to the preceding cHF-feeding for 4 months. DHA/EPA administered as phospholipids prevented glucose intolerance and tended to reduce obesity better than triglycerides. Lipemia and hepatosteatosis were suppressed more in response to dietary phospholipids, in correlation with better bioavailability of DHA and EPA, and a higher DHA accumulation in the liver, white adipose tissue (WAT), and muscle phospholipids. In dietary obese mice, both DHA/EPA concentrates prevented a further weight gain, reduced plasma lipid levels to a similar extent, and tended to improve glucose tolerance. Importantly, only the phospholipid form reduced plasma insulin and adipocyte hypertrophy, while being more effective in reducing hepatic steatosis and low-grade inflammation of WAT. These beneficial effects were correlated with changes of endocannabinoid metabolome in WAT, where phospholipids reduced 2-arachidonoylglycerol, and were more effective in increasing anti-inflammatory lipids such as N-docosahexaenoylethanolamine.
Compared with triglycerides, dietary DHA/EPA administered as phospholipids are superior in preserving a healthy metabolic profile under obesogenic conditions, possibly reflecting better bioavalability and improved modulation of the endocannabinoid system activity in WAT.
Hedonic hunger refers to consumption of food just for pleasure and not to maintain energy homeostasis. In this condition, the subject eats also when not in a state of short-term energy depletion, and food is consumed uniquely because of its gustatory rewarding properties. The physiological mechanisms underlying this eating behavior are not deeply understood, but endogenous rewarding mediators like ghrelin and endocannabinoids are likely involved.
To explore the role of these substances in hedonic eating, we measured changes in their plasma levels in eight satiated healthy subjects after ad libitum consumption of highly palatable food as compared with the consumption of nonpalatable food in isoenergetic amounts with the same nutrient composition of the palatable food.
The consumption of food for pleasure was characterized by increased peripheral levels of both the peptide ghrelin and the endocannabinoid 2-arachidonoyl-glycerol. Levels of the other endocannabinoid anandamide and of anandamide-related mediators oleoylethanolamide and palmitoylethanolamide, instead, progressively decreased after the ingestion of both highly pleasurable and isoenergetic nonpleasurable food. A positive correlation was found between plasma 2-arachidonoyl glycerol and ghrelin during hedonic but not nonhedonic, eating.
The present preliminary findings suggest that when motivation to eat is generated by the availability of highly palatable food and not by food deprivation, a peripheral activation of two endogenous rewarding chemical signals is observed. Future research should confirm and extend our results to better understand the phenomenon of hedonic eating, which influences food intake and, ultimately, body mass.
Background/aims:
Antagonism of the endocannabinoid receptor-1 (CB1R) directly improves whole-body metabolic parameters of insulin resistance. The present investigation determined the effects of chronic CB1R antagonism on whole-body and skeletal-muscle insulin action in insulin-sensitive lean and insulin-resistant obese Zucker rats.
Methods:
Animals were either fed ad libitum or in pairs, or treated with SR141716 (10 mg/kg i.p. for 14 days).
Results:
Food intake was significantly reduced (p < 0.05) after initial SR141716 treatment and remained decreased in both lean and obese animals until day 13. Fasting plasma glucose decreased (24%) and insulin increased (43%) in lean SR141716-treated (24%) rats compared to lean ad libitum-fed controls, but not in the corresponding obese groups. Fasting plasma free fatty acids were reduced by CB1R antagonism in lean (21%) and obese (42%) animals. Whole-body insulin sensitivity was increased (36%) in obese SR141716-treated rats compared to obese ad libitum-fed controls, which was associated with reduced insulin secretion during an oral glucose tolerance test. Insulin-stimulated glucose transport activity in the soleus was greatest in the respective SR141716-treated lean and obese groups compared to the corresponding ad libitum- and pair-fed controls. Chronic SR141716 treatment did not induce alterations in signaling factors associated with the regulation of glucose transport [protein kinase B (Akt), glycogen synthase kinase-3β, 5'-AMP-dependent protein kinase, or p38 mitogen-activated protein kinase] in the soleus.
Conclusions:
These results indicate that, while the chronic treatment with CB1R antagonism markedly diminished food intake in lean and obese Zucker rats, there are also significant metabolic improvements in whole-body and skeletal-muscle insulin action mediated by CB1R antagonism through mechanisms independent of reduced caloric intake.
Impaired aerobic exercise capacity and skeletal muscle dysfunction are associated with cardiometabolic diseases. Acute administration of capsaicin enhances exercise endurance in rodents, but the long-term effect of dietary capsaicin is unknown. The capsaicin receptor, the transient receptor potential vanilloid 1 (TRPV1) cation channel has been detected in skeletal muscle, the role of which remains unclear. Here we report the function of TRPV1 in cultured C2C12 myocytes and the effect of TRPV1 activation by dietary capsaicin on energy metabolism and exercise endurance of skeletal muscles in mice. In vitro, capsaicin increased cytosolic free calcium and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression in C2C12 myotubes through activating TRPV1. In vivo, PGC-1α in skeletal muscle was upregulated by capsaicin-induced TRPV1 activation or genetic overexpression of TRPV1 in mice. TRPV1 activation increased the expression of genes involved in fatty acid oxidation and mitochondrial respiration, promoted mitochondrial biogenesis, increased oxidative fibers, enhanced exercise endurance and prevented high-fat diet-induced metabolic disorders. Importantly, these effects of capsaicin were absent in TRPV1-deficient mice. We conclude that TRPV1 activation by dietary capsaicin improves energy metabolism and exercise endurance by upregulating PGC-1α in skeletal muscles. The present results indicate a novel therapeutic strategy for managing metabolic diseases and improving exercise endurance.
The elucidation of the role of endocannabinoids in physiological and pathological conditions and the transferability of the importance of these mediators from basic evidence into clinical practice is still hampered by the indefiniteness of their circulating reference intervals. In this work, we developed and validated a two-dimensional LC/MS/MS method for the simultaneous measurement of plasma endocannabinoids and related compounds such as arachidonoyl-ethanolamide, palmitoyl-ethanolamide, and oleoyl-ethanolamide, belonging to the N-acyl-ethanolamide (NAE) family, and 2-arachidonoyl-glycerol and its inactive isomer 1-arachidonoyl-glycerol from the monoacyl-glycerol (MAG) family. We found that several pitfalls in the endocannabinoid measurement may occur, from blood withdrawal to plasma processing. Plasma extraction with toluene followed by on-line purification was chosen, allowing high-throughput and reliability. We estimated gender-specific reference intervals on 121 healthy normal weight subjects fulfilling rigorous anthropometric and hematic criteria. We observed no gender differences for NAEs, whereas significantly higher MAG levels were found in males compared with females. MAGs also significantly correlated with triglycerides. NAEs increased with age in females, and arachidonoyl-ethanolamide correlated with adiposity and metabolic parameters in females. This work paves the way to the establishment of definitive reference intervals for circulating endocannabinoids to help physicians move from the speculative research field into the clinical field.
Endocannabinoids regulate energy balance and lipid metabolism by stimulating the cannabinoid receptor type 1 (CB1). Genetic deletion and pharmacological antagonism have shown that CB1 signaling is necessary for the development of obesity and related metabolic disturbances. However, the sufficiency of endogenously produced endocannabinoids to cause hepatic lipid accumulation and insulin resistance, independent of food intake, has not been demonstrated. Here, we show that a single administration of isopropyl dodecylfluorophosphonate (IDFP), perhaps the most potent pharmacological inhibitor of endocannabinoid degradation, increases hepatic triglycerides (TG) and induces insulin resistance in mice. These effects involve increased CB1 signaling, as they are mitigated by pre-administration of a CB1 antagonist (AM251) and in CB1 knockout mice. Despite the strong physiological effects of CB1 on hepatic lipid and glucose metabolism, little is known about the downstream targets responsible for these effects. To elucidate transcriptional targets of CB1 signaling, we performed microarrays on hepatic RNA isolated from DMSO (control), IDFP and AM251/IDFP-treated mice. The gene for the secreted glycoprotein lipocalin 2 (lcn2), which has been implicated in obesity and insulin resistance, was among those most responsive to alterations in CB1 signaling. The expression pattern of IDFP mice segregated from DMSO mice in hierarchal cluster analysis and AM251 pre-administration reduced (>50%) the majority (303 of 533) of the IDFP induced alterations. Pathway analysis revealed that IDFP altered expression of genes involved in lipid, fatty acid and steroid metabolism, the acute phase response, and amino acid metabolism in a CB1-dependent manner. PCR confirmed array results of key target genes in multiple independent experiments. Overall, we show that acute IDFP treatment induces hepatic TG accumulation and insulin resistance, at least in part through the CB1 receptor, and identify novel cannabinoid responsive genes.
Phospholipase A(2)(PLA(2)) enzymes are considered the primary source of arachidonic acid for cyclooxygenase (COX)-mediated biosynthesis of prostaglandins. Here, we show that a distinct pathway exists in brain, where monoacylglycerol lipase (MAGL) hydrolyzes the endocannabinoid 2-arachidonoylglycerol to generate a major arachidonate precursor pool for neuroinflammatory prostaglandins. MAGL-disrupted animals show neuroprotection in a parkinsonian mouse model. These animals are spared the hemorrhaging caused by COX inhibitors in the gut, where prostaglandins are instead regulated by cytosolic PLA(2). These findings identify MAGL as a distinct metabolic node that couples endocannabinoid to prostaglandin signaling networks in the nervous system and suggest that inhibition of this enzyme may be a new and potentially safer way to suppress the proinflammatory cascades that underlie neurodegenerative disorders.
We examined the physiological mechanisms by which cannabinoid receptor 1 (CB1) antagonism improves glucose metabolism and insulin sensitivity independent of its anorectic and weight-reducing effects, as well as the effects of CB1 antagonism on brown adipose tissue (BAT) function.
Three groups of diet-induced obese mice received for 1 month: vehicle; the selective CB1 antagonist SR141716; or vehicle/pair-feeding. After measurements of body composition and energy expenditure, mice underwent euglycaemic-hyperinsulinaemic clamp studies to assess in vivo insulin action. In separate cohorts, we assessed insulin action in weight-reduced mice with diet-induced obesity (DIO), and the effect of CB1 antagonism on BAT thermogenesis. Surgical denervation of interscapular BAT (iBAT) was carried out in order to study the requirement for the sympathetic nervous system in mediating the effects of CB1 antagonism on BAT function.
Weight loss associated with chronic CB1 antagonism was accompanied by increased energy expenditure, enhanced insulin-stimulated glucose utilisation, and marked activation of BAT thermogenesis. Insulin-dependent glucose uptake was significantly increased in white adipose tissue and BAT, whereas glycogen synthesis was increased in liver, fat and muscle. Despite marked weight loss in the mice, SR141716 treatment did not improve insulin-mediated suppression of hepatic glucose production nor increase skeletal muscle glucose uptake. Denervation of iBAT blunted the effect of SR141716 on iBAT differentiation and insulin-mediated glucose uptake.
Chronic CB1 antagonism markedly enhances insulin-mediated glucose utilisation in DIO mice, independent of its anorectic and weight-reducing effects. The potent effect on insulin-stimulated BAT glucose uptake reveals a novel role for CB1 receptors as regulators of glucose metabolism.
The endocannabinoid system (ECS) is a ubiquitously expressed signalling system, with involvement in lipid metabolism and obesity. There are reported changes in obesity of blood concentrations of the endocannabinoids anandamide (AEA) and 2-arachidonoylglcyerol (2-AG), and of adipose tissue expression levels of the two key catabolic enzymes of the ECS, fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MGL). Surprisingly, however, the activities of these enzymes have not been assayed in conditions of increasing adiposity. The aim of the current study was to investigate whether FAAH and MGL activities in human subcutaneous adipocytes are affected by body mass index (BMI), or other markers of adiposity and metabolism.
Subcutaneous abdominal mature adipocytes, fasting blood samples and anthropometric measurements were obtained from 28 metabolically healthy subjects representing a range of BMIs. FAAH and MGL activities were assayed in mature adipocytes using radiolabelled substrates. Serum glucose, insulin and adipokines were determined using ELISAs.
MGL activity showed no relationship with BMI or other adiposity indices, metabolic markers (fasting serum insulin or glucose) or serum adipokine levels (adiponectin, leptin or resistin). In contrast, FAAH activity in subcutaneous adipocytes correlated positively with BMI and waist circumference, but not with skinfold thickness, metabolic markers or serum adipokine levels.
In this study, novel evidence is provided that FAAH activity in subcutaneous mature adipocytes increases with BMI, whereas MGL activity does not. These findings support the hypothesis that some components of the ECS are upregulated with increasing adiposity in humans, and that AEA and 2-AG may be regulated differently.
Cannabinoid receptor CB1 is expressed abundantly in the brain and presumably in the peripheral tissues responsible for energy metabolism. It is unclear if the antiobesity effects of rimonabant, a CB1 antagonist, are mediated through the central or the peripheral CB1 receptors. To address this question, we generated transgenic mice with central nervous system (CNS)-specific knockdown (KD) of CB1, by expressing an artificial microRNA (AMIR) under the control of the neuronal Thy1.2 promoter. In the mutant mice, CB1 expression was reduced in the brain and spinal cord, whereas no change was observed in the superior cervical ganglia (SCG), sympathetic trunk, enteric nervous system, and pancreatic ganglia. In contrast to the neuronal tissues, CB1 was undetectable in the brown adipose tissue (BAT) or the liver. Consistent with the selective loss of central CB1, agonist-induced hypothermia was attenuated in the mutant mice, but the agonist-induced delay of gastrointestinal transit (GIT), a primarily peripheral nervous system-mediated effect, was not. Compared to wild-type (WT) littermates, the mutant mice displayed reduced body weight (BW), adiposity, and feeding efficiency, and when fed a high-fat diet (HFD), showed decreased plasma insulin, leptin, cholesterol, and triglyceride levels, and elevated adiponectin levels. Furthermore, the therapeutic effects of rimonabant on food intake (FI), BW, and serum parameters were markedly reduced and correlated with the degree of CB1 KD. Thus, KD of CB1 in the CNS recapitulates the metabolic phenotype of CB1 knockout (KO) mice and diminishes rimonabant's efficacy, indicating that blockade of central CB1 is required for rimonabant's antiobesity actions.
Omega-3 polyunsaturated fatty acids (ω-3-PUFA) are known to ameliorate several metabolic risk factors for cardiovascular disease, and an association between elevated peripheral levels of endogenous ligands of cannabinoid receptors (endocannabinoids) and the metabolic syndrome has been reported. We investigated the dose-dependent effects of dietary ω-3-PUFA supplementation, given as krill oil (KO), on metabolic parameters in high fat diet (HFD)-fed mice and, in parallel, on the levels, in inguinal and epididymal adipose tissue (AT), liver, gastrocnemius muscle, kidneys and heart, of: 1) the endocannabinoids, anandamide and 2-arachidonoylglycerol (2-AG), 2) two anandamide congeners which activate PPARα but not cannabinoid receptors, N-oleoylethanolamine and N-palmitoylethanolamine, and 3) the direct biosynthetic precursors of these compounds.
Lipids were identified and quantified using liquid chromatography coupled to atmospheric pressure chemical ionization single quadrupole mass spectrometry (LC-APCI-MS) or high resolution ion trap-time of flight mass spectrometry (LC-IT-ToF-MS).
Eight-week HFD increased endocannabinoid levels in all tissues except the liver and epididymal AT, and KO reduced anandamide and/or 2-AG levels in all tissues but not in the liver, usually in a dose-dependent manner. Levels of endocannabinoid precursors were also generally down-regulated, indicating that KO affects levels of endocannabinoids in part by reducing the availability of their biosynthetic precursors. Usually smaller effects were found of KO on OEA and PEA levels.
Our data suggest that KO may promote therapeutic benefit by reducing endocannabinoid precursor availability and hence endocannabinoid biosynthesis.
Oral sensory signals drive dietary fat intake, but the neural mechanisms underlying this process are largely unknown. The endocannabinoid system has gained recent attention for its central and peripheral roles in regulating food intake, energy balance, and reward. Here, we used a sham-feeding paradigm, which isolates orosensory from postingestive influences of foods, to examine whether endocannabinoid signaling participates in the positive feedback control of fat intake. Sham feeding a lipid-based meal stimulated endocannabinoid mobilization in the rat proximal small intestine by altering enzymatic activities that control endocannabinoid metabolism. This effect was abolished by surgical transection of the vagus nerve and was not observed in other peripheral organs or in brain regions that control feeding. Sham feeding of a nutritionally complete liquid meal produced a similar response to that of fat, whereas protein or carbohydrate alone had no such effect. Local infusion of the CB(1)-cannabinoid receptor antagonist, rimonabant, into the duodenum markedly reduced fat sham feeding. Similarly to rimonabant, systemic administration of the peripherally restricted CB(1)-receptor antagonist, URB 447, attenuated sham feeding of lipid. Collectively, the results suggest that the endocannabinoid system in the gut exerts a powerful regulatory control over fat intake and might be a target for antiobesity drugs.
Activated cannabinoid 1 receptor (CB1R) signaling has been implicated in the development of phenotypes associated with fatty liver, insulin resistance, and impaired suppression of hepatic glucose output. Endoplasmic reticulum stress-associated liver-specific transcription factor CREBH is emerging as a critical player in various hepatic metabolic pathways and regulates hepatic gluconeogenesis in diet-induced obese settings. In this study, we elucidated the critical role of CREBH in mediating CB1R signaling to regulate glucose homeostasis in primary rat and human hepatocytes. mRNA and protein levels and glucose production were analyzed in primary rat and human hepatocytes. ChIP assays were performed together with various transcriptional analyses using standard techniques. CB1R activation by 2-arachidonoylglycerol (2-AG) specifically induced CREBH gene expression via phosphorylation of the JNK signaling pathway and c-Jun binding to the AP-1 binding site in the CREBH gene promoter. 2-AG treatment significantly induced hepatic gluconeogenic gene expression and glucose production in primary hepatocytes, and we demonstrated that the CREBH binding site mutant significantly attenuated 2-AG-mediated activation of the gluconeogenic gene promoter. Endogenous knockdown of CREBH led to ablation of 2-AG-induced gluconeogenic gene expression and glucose production, and the CB1R antagonist AM251 or insulin exhibited repression of CREBH gene induction and subsequently inhibited gluconeogenesis in both rat and human primary hepatocytes. These results demonstrate a novel mechanism of action of activated CB1R signaling to induce hepatic gluconeogenesis via direct activation of CREBH, thereby contributing to a better understanding of the endocannabinoid signaling mechanism involved in regulating the hepatic glucose metabolism.
Since the first reports of endocannabinoid-mediated retrograde signaling in 2001, great advances have been made toward understanding the molecular basis and functions of the endocannabinoid system. Electrophysiological studies have revealed that the endocannabinoid system is functional at various types of synapses throughout the brain. Basic mechanisms have been clarified as to how endocannabinoids are produced and released from postsynaptic neurons and regulate neurotransmitter release through activating presynaptic cannabinoid CB(1) receptors, although there remain unsolved questions and some discrepancies. In addition to this major function, recent studies suggest diverse functions of endocannabinoids, including control of other endocannabinoid-independent forms of synaptic plasticity, regulation of neuronal excitability, stimulation of glia-neuron interaction, and induction of CB(1)R-independent plasticity. Using recently developed pharmacological and genetic tools, behavioral studies have elucidated the roles of the endocannabinoid system in various aspects of neural functions. In this review, we make a brief overview of molecular mechanisms underlying the endocannabinoid-mediated synaptic modulation and also summarize recent findings, which shed new light on a diversity of functional roles of endocannabinoids.
Monoglyceride lipase (MGL) influences energy metabolism by at least two mechanisms. First, it hydrolyzes monoacylglycerols (MG) into fatty acids and glycerol. These products can be used for energy production or synthetic reactions. Second, MGL degrades 2-arachidonoyl glycerol (2-AG), the most abundant endogenous ligand of cannabinoid receptors (CBR). Activation of CBR affects energy homeostasis by central orexigenic stimuli, by promoting lipid storage, and by reducing energy expenditure. To characterize the metabolic role of MGL in vivo, we generated an MGL-deficient mouse model (MGL-ko). These mice exhibit a reduction in MG hydrolase activity and a concomitant increase in MG levels in adipose tissue, brain, and liver. In adipose tissue, the lack of MGL activity is partially compensated by hormone-sensitive lipase. Nonetheless, fasted MGL-ko mice exhibit reduced plasma glycerol and triacylglycerol, as well as liver triacylglycerol levels indicative for impaired lipolysis. Despite a strong elevation of 2-AG levels, MGL-ko mice exhibit normal food intake, fat mass, and energy expenditure. Yet mice lacking MGL show a pharmacological tolerance to the CBR agonist CP 55,940 suggesting that the elevated 2-AG levels are functionally antagonized by desensitization of CBR. Interestingly, however, MGL-ko mice receiving a high fat diet exhibit significantly improved glucose tolerance and insulin sensitivity in comparison with wild-type controls despite equal weight gain. In conclusion, our observations implicate that MGL deficiency impairs lipolysis and attenuates diet-induced insulin resistance. Defective degradation of 2-AG does not provoke cannabinoid-like effects on feeding behavior, lipid storage, and energy expenditure, which may be explained by desensitization of CBR.
The endocannabinoid (EC) system has been implicated as an important regulator of energy homeostasis. In obesity and type 2 diabetes, EC tone is elevated in peripheral tissues including liver, muscle, fat, and also centrally, particularly in the hypothalamus. Cannabinoid receptor type 1 (CB₁) blockade with the centrally and peripherally acting rimonabant induces weight loss and improves glucose homeostasis while also causing psychiatric adverse effects. The relative contributions of peripheral versus central EC signaling on glucose homeostasis remain to be elucidated. The aim of this study was to test whether the central EC system regulates systemic glucose fluxes.
We determined glucose and lipid fluxes in male Sprague-Dawley rats during intracerebroventricular infusions of either WIN55,212-2 (WIN) or arachidonoyl-2'-chloroethylamide (ACEA) while controlling circulating insulin and glucose levels through hyperinsulinemic, euglycemic clamp studies. Conversely, we fed rats a high-fat diet for 3 days and then blocked central EC signaling with an intracerebroventricular infusion of rimonabant while assessing glucose fluxes during a clamp.
Central CB₁ activation is sufficient to impair glucose homeostasis. Either WIN or ACEA infusions acutely impaired insulin action in both liver and adipose tissue. Conversely, in a model of overfeeding-induced insulin resistance, CB₁ antagonism restored hepatic insulin sensitivity.
Thus central EC tone plays an important role in regulating hepatic and adipose tissue insulin action. These results indicate that peripherally restricted CB₁ antagonists, which may lack psychiatric side effects, are also likely to be less effective than brain-permeable CB₁ antagonists in ameliorating insulin resistance.
Optimal glucose homeostasis requires exquisitely precise adaptation of the number of insulin-secreting β-cells in the islets of Langerhans. Insulin itself positively regulates β-cell proliferation in an autocrine manner through the insulin receptor (IR) signaling pathway. It is now coming to light that cannabinoid 1 receptor (CB1R) agonism/antagonism influences insulin action in insulin-sensitive tissues. However, the cells on which the CB1Rs are expressed and their function in islets have not been firmly established. We undertook the current study to investigate if intraislet endogenous cannabinoids (ECs) regulate β-cell proliferation and if they influence insulin action.
We measured EC production in isolated human and mouse islets and β-cell line in response to glucose and KCl. We evaluated human and mouse islets, several β-cell lines, and CB1R-null (CB1R(-/-)) mice for the presence of a fully functioning EC system. We investigated if ECs influence β-cell physiology through regulating insulin action and demonstrated the therapeutic potential of manipulation of the EC system in diabetic (db/db) mice.
ECs are generated within β-cells, which also express CB1Rs that are fully functioning when activated by ligands. Genetic and pharmacologic blockade of CB1R results in enhanced IR signaling through the insulin receptor substrate 2-AKT pathway in β-cells and leads to increased β-cell proliferation and mass. CB1R antagonism in db/db mice results in reduced blood glucose and increased β-cell proliferation and mass, coupled with enhanced IR signaling in β-cells. Furthermore, CB1R activation impedes insulin-stimulated IR autophosphorylation on β-cells in a Gα(i)-dependent manner.
These findings provide direct evidence for a functional interaction between CB1R and IR signaling involved in the regulation of β-cell proliferation and will serve as a basis for developing new therapeutic interventions to enhance β-cell function and proliferation in diabetes.
International Journal of Obesity is a monthly, multi-disciplinary forum for papers describing basic, clinical and applied studies in biochemistry, genetics and nutrition, together with molecular, metabolic, psychological and epidemiological aspects of obesity and related disorders