Tag Archives: 2-AG

Endocannabinoids Measurement in Human Saliva as Potential Biomarker of Obesity

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Background

“The discovery of the endocannabinoid system and of its role in the regulation of energy balance has significantly advanced our understanding of the physiopathological mechanisms leading to obesity and type 2 diabetes. New knowledge on the role of this system in humans has been acquired by measuring blood endocannabinoids. Here we explored endocannabinoids and related N-acylethanolamines in saliva and verified their changes in relation to body weight status and in response to a meal or to body weight loss.”

“The discovery of the endocannabinoid system (ECS) and of its impact on the regulation of energy homeostasis represents a significant advance in the study of obesity and type 2 diabetes [1]–[4].”

“The saliva is the first digestive secretion produced in response to the ingestion of food [11]. Therefore, it is reasonable to investigate whether signals and systems involved in the regulation of food intake, such as the ECS, might be present in saliva and exert a functional role. Besides, saliva offers distinctive advantages over serum or plasma as a diagnostic tool, thanks to the non-invasiveness of the collection procedure.”

“The ECS is present in human salivary glands.”

“Changes in salivary endocannabinoids and N-acylethanolamines levels in response to body weight loss.”

“Here we demonstrate that endocannabinoids and related N-acylethanolamines can be reliably detected and quantified in human saliva. Similarly to what already reported for circulating levels in the blood [7], [9], [10], the salivary concentration of AEA and OEA were significantly increased in obese, insulin-resistant subjects as compared to normal weight controls.”

“the present findings overall indicate that salivary AEA might be a useful biomarker in human obesity, in particular considering that salivary samples are easy to collect, require a non-invasive procedure advantageous when performing studies in obese subjects in whom venipuncture may be difficult, and can be repeatedly collected at home by the patient during a therapeutic intervention. This type of tool could therefore be used to better phenotype the obese population, assess responses to treatment, or to further study the physiology of the ECS in humans, by investigating salivary endocannabinoid responses under various conditions.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3409167/

The endocannabinoid system, eating behavior and energy homeostasis: the end or a new beginning?

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Abstract

“The endocannabinoid system (ECS) consists of two receptors (CB(1) and CB(2)), several endogenous ligands (primarily anandamide and 2-AG), and over a dozen ligand-metabolizing enzymes. The ECS regulates many aspects of embryological development and homeostasis, including neuroprotection and neural plasticity, immunity and inflammation, apoptosis and carcinogenesis, pain and emotional memory, and the focus of this review: hunger, feeding, and metabolism. This mini-review summarizes the main findings that supported the clinical use of CB1 antagonists/inverse agonists, the clinical concerns that have emerged, and the possible future of cannabinoid-based therapy of obesity and related diseases. The ECS controls energy balance and lipid metabolism centrally (in the hypothalamus and mesolimbic pathways) and peripherally (in adipocytes, liver, skeletal muscle and pancreatic islet cells), acting through numerous anorexigenic and orexigenic pathways. Obese people seem to display an increased endocannabinoid tone, driving CB(1) receptor in a feed-forward dysfunction. Several CB(1) antagonists/inverse agonists have been developed for the treatment of obesity. Although these drugs were found to be efficacious at reducing food intake as well as abdominal adiposity and cardiometabolic risk factors, they resulted in adverse psychiatric effects that limited their use and finally led to the end of the clinical use of systemic CB(1) ligands with significant inverse agonist activity for complicated obesity. However, the existence of alternatives such as CB(1) partial agonists, neutral antagonists, antagonists restricted to the periphery, allosteric modulators and other potential targets within the ECS indicate that a cannabinoid-based therapy for the management of obesity and its associated cardiometabolic sequelae should remain open for consideration.”

http://www.ncbi.nlm.nih.gov/pubmed/20347862

Understanding metabolic homeostasis and imbalance: what is the role of the endocannabinoid system?

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Abstract

“Endogenous endocannabinoids (ECs) (anandamide and 2-arachidonoyl glycerol) are part of the leptin-regulated neural circuitry involved in appetite regulation. One of the sites of the orexigenic action of ECs involves activation of cannabinoid-1 (CB1) receptors in the lateral hypothalamus, from which neurons involved in mediating food reward project into the limbic system. In animal models of obesity, pharmacologic blockade or genetic ablation of CB1 receptors causes a transient reduction in food intake accompanied by sustained weight loss, reduced adiposity, and reversal of hormonal/metabolic changes, such as elevated levels of plasma leptin, insulin, glucose, and triglyceride, and reduced levels of plasma adiponectin (Acrp30). However, the beneficial effects of CB1 blockade on weight and metabolism cannot be explained by appetite suppression alone. Animal studies suggest that CB1 blockade exerts a direct peripheral as well as a central effect on fat metabolism. CB1 receptor blockade with rimonabant has been shown to not only reduce weight and adiposity but also to directly modulate fat metabolism at peripheral sites in skeletal muscle, adipose tissue, and the liver. Preclinical animal studies suggest that CB1 blockade acts on adipocytes to increase Acrp30 expression, on hepatocytes to decrease de novo lipogenesis and increase fatty acid oxidation, and on skeletal muscle to reduce blood glucose and insulin levels. Extrapolating from animal studies to the clinic, CB1 receptor blockade offers a promising strategy not only for reducing weight and abdominal adiposity but also for preventing and reversing its metabolic consequences.”

http://www.ncbi.nlm.nih.gov/pubmed/17720356

The future of weight loss: A ‘marijuana’ diet pill?

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“Limiting a brain compound that regulates metabolism allows genetically altered mice to stay skinny without exercising. Is a dream pill far behind?

If you find the prospect of staying thin while eating as much as you want appealing, scientists have news for you. New research from the University of California, Irvine — detailed in the March issue of Cell Metabolism — found that certain brain chemicals with characteristics similar to marijuana might help the body shed pounds without any exercise. A dream come true? Here’s a brief look at the promising discovery:

What chemical could have such power?
It’s an endocannabinoid compound called 2-AG. Endocannabinoids, as the name might suggest, share a similar molecular structure to the active ingredients in cannabis. Typically, high levels of 2-AG are found in the brains of mammals, and previous studies suggested that these compounds may make the body crave fat. Scientists think endocannabinoids play a key role in regulating the body’s metabolism, or the energy it makes from food.

How did scientists put the compound to the test?
Researchers genetically engineered brain cells in mice to exhibit low levels of 2-AG, on the theory that this would allow the rodents’ metabolic rates to “go crazy,” says Kristen Philipkoski at Gizmodo. And the hunch was right. These mice lived in a “hypermetabolic state,” burning fat calories far more efficiently than normal mice, study researcher Daniele Piomeli said in a statement. They were “resistant to obesity,” staying thin despite a high-fat diet without exercise. They even had normal blood pressure, and showed no increased risk of heart disease or diabetes. 

How could this discovery help humans?
“To produce the desired effects, we would need to create a drug that blocks 2-AG production in the brain,” says Piomeli, “something we’re not yet able to do.” 

So can we expect a miracle pill in the foreseeable future?
“Tweaking” human brain chemistry is no easy task, says Philipkoski. And preliminary estimates say it would take a decade and cost up to $2 billion to make the drug safe and effective enough for the FDA to to approve it. “So don’t cancel that gym membership just yet,” says Piomeli.”

http://news.yahoo.com/future-weight-loss-marijuana-diet-pill-071500947.html

Activation of the peripheral endocannabinoid system in human obesity.

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Abstract

“Obesity is the main risk factor for the development of type 2 diabetes. Activation of the central endocannabinoid system increases food intake and promotes weight gain. Blockade of the cannabinoid type 1 (CB-1) receptor reduces body weight in animals by central and peripheral actions; the role of the peripheral endocannabinoid system in human obesity is now being extensively investigated. We measured circulating endocannabinoid concentrations and studied the expression of CB-1 and the main degrading enzyme, fatty acid amide hydrolase (FAAH), in adipose tissue of lean (n = 20) and obese (n = 20) women and after a 5% weight loss in a second group of women (n = 17). Circulating levels of anandamide and 1/2-arachidonoylglycerol were increased by 35 and 52% in obese compared with lean women (P < 0.05). Adipose tissue mRNA levels were reduced by -34% for CB-1 and -59% for FAAH in obese subjects (P < 0.05). A strong negative correlation was found between FAAH expression in adipose tissue and circulating endocannabinoids. Circulating endocannabinoids and CB-1 or FAAH expression were not affected by 5% weight loss. The expression of CB-1 and FAAH was increased in mature human adipocytes compared with in preadipocytes and was found in several human tissues. Our findings support the presence of a peripheral endocannabinoid system that is upregulated in human obesity.”

“We demonstrated that the CB-1 receptor is expressed in organs relevant to the pathogenesis of obesity in humans, so that results from mechanistic studies in animals may also be applicable to patients. Furthermore, the peripheral endocannabinoid system is activated in human obesity. The observation that endocannabinoid activation is not reversible with a 5% weight loss may suggest that this activation is a cause rather than a consequence of obesity. The physiology and pathophysiology of the peripheral adipose tissue endocannabinoid system warrant further studies.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2228268/

Dysregulation of the Peripheral and Adipose Tissue Endocannabinoid System in Human Abdominal Obesity

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Abstract

“The endocannabinoid system has been suspected to contribute to the association of visceral fat accumulation with metabolic diseases. We determined whether circulating endocannabinoids are related to visceral adipose tissue mass in lean, subcutaneous obese, and visceral obese subjects (10 men and 10 women in each group). We further measured expression of the cannabinoid type 1 (CB(1)) receptor and fatty acid amide hydrolase (FAAH) genes in paired samples of subcutaneous and visceral adipose tissue in all 60 subjects. Circulating 2-arachidonoyl glycerol (2-AG) was significantly correlated with body fat (r = 0.45, P = 0.03), visceral fat mass (r = 0.44, P = 0.003), and fasting plasma insulin concentrations (r = 0.41, P = 0.001) but negatively correlated to glucose infusion rate during clamp (r = 0.39, P = 0.009). In visceral adipose tissue, CB(1) mRNA expression was negatively correlated with visceral fat mass (r = 0.32, P = 0.01), fasting insulin (r = 0.48, P < 0.001), and circulating 2-AG (r = 0.5, P < 0.001), whereas FAAH gene expression was negatively correlated with visceral fat mass (r = 0.39, P = 0.01) and circulating 2-AG (r = 0.77, P < 0.001). Our findings suggest that abdominal fat accumulation is a critical correlate of the dysregulation of the peripheral endocannabinoid system in human obesity. Thus, the endocannabinoid system may represent a primary target for the treatment of abdominal obesity and associated metabolic changes.”

“In conclusion, extending previous observations that the peripheral endocannabinoid system may be activated in human obesity (21), we demonstrate here that visceral fat accumulation is an important correlate of an activated peripheral endocannabinoid system. In addition, strong expression of CB1 receptors in visceral adipose tissue could represent a primary target for the beneficial effects of CB1 blockade on different components of the metabolic syndrome.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2228260/

Dysregulation of the endocannabinoid system in obesity.

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Abstract

“An activation of the endocannabinoid system (ECS) in obesity with increased concentrations of endocannabinoids in several tissues and in the circulation is described in this review. This increased availability of endocannabinoids might stimulate cannabinoid receptors in a pathophysiological manner. The successful use of the cannabinoid receptor CB(1) inverse agonists rimonabant and taranabant for weight loss and the treatment of obesity-associated metabolic disorders might well be through blocking this overstimulation of cannabinoid receptors. At present, no single mechanism has been identified that explains the increased bioavailability of endocannabinoids in obesity. Both increased synthesis and decreased degradation appear to operate in a species- and tissue-dependent manner, but many pieces of the puzzle still need to be collected. For example, most data show decreased fatty acid amide hydrolase (FAAH) expression and/or activity as a result of obesity or high-fat intake, but the endocannabinoid predominantly increased in tissues is 2-arachidonoylglycerol (2-AG), which is not degraded by FAAH in vivo. Furthermore, the influence of dietary fatty acids on the synthesis of endocannabinoids needs to be studied in much more detail. Although weight loss does not seem to influence activation of the endocannabinoid system (ECS) in human obesity, suggesting an underlying mechanisms independent of body weight, no such mechanism at the genetic level has yet been identified either. Thus, activation of the ECS is a hallmark of abdominal obesity, and explains the success of pharmacological CB(1) blockade, but serious attempts have to be made to clarify the underlying mechanisms of this activation.”

http://www.ncbi.nlm.nih.gov/pubmed/18426509

Cannabinoid drugs and enhancement of endocannabinoid responses: strategies for a wide array of disease states.

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Abstract

“The endogenous cannabinoid system has revealed potential avenues to treat many disease states. Medicinal indications of cannabinoid drugs including compounds that result in enhanced endocannabinoid responses (EER) have expanded markedly in recent years. The wide range of indications covers chemotherapy complications, tumor growth, addiction, pain, multiple sclerosis, glaucoma, inflammation, eating disorders, age-related neurodegenerative disorders, as well as epileptic seizures, traumatic brain injury, cerebral ischemia, and other excitotoxic insults. Indeed, a great effort has led to the discovery of agents that selectively activate the cannabinoid system or that enhance the endogenous pathways of cannabinergic signaling. The endocannabinoid system is comprised of three primary components: (i) cannabinoid receptors, (ii) endocannabinoid transport system, and (iii) hydrolysis enzymes that break down the endogenous ligands. Two known endocannabinoids, anandamide (AEA) and 2-arachidonoyl glycerol (2-AG), are lipid molecules that are greatly elevated in response to a variety of pathological events. This increase in endocannabinoid levels is suggested to be part of an on-demand compensatory response. Furthermore, activation of signaling pathways mediated by the endogenous cannabinoid system promotes repair and cell survival. Similar cell maintenance effects are elicited by EER through inhibitors of the endocannabinoid deactivation processes (i.e., internalization and hydrolysis). The therapeutic potential of the endocannabinoid system has yet to be fully determined, and the number of medical maladies that may be treated will likely continue to grow. This review will underline studies that demonstrate medicinal applications for agents that influence the endocannabinoid system.”

http://www.ncbi.nlm.nih.gov/pubmed/17022737

The Endocannabinoid System and the Brain.

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Abstract

“The psychoactive constituent in cannabis, Δ(9)-tetrahydrocannabinol (THC), was isolated in the mid-1960s, but the cannabinoid receptors, CB1 and CB2, and the major endogenous cannabinoids (anandamide and 2-arachidonoyl glycerol) were identified only 20 to 25 years later. The cannabinoid system affects both central nervous system (CNS) and peripheral processes. In this review, we have tried to summarize research-with an emphasis on recent publications-on the actions of the endocannabinoid system on anxiety, depression, neurogenesis, reward, cognition, learning, and memory. The effects are at times biphasic-lower doses causing effects opposite to those seen at high doses. Recently, numerous endocannabinoid-like compounds have been identified in the brain. Only a few have been investigated for their CNS activity, and future investigations on their action may throw light on a wide spectrum of brain functions. Expected final online publication date for the Annual Review of Psychology Volume 64 is November 30, 2012. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.”

http://www.ncbi.nlm.nih.gov/pubmed/22804774

Endocannabinoid system: An overview of its potential in current medical practice.

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Abstract

“The endocannabinoid system (ECS) is a lipid signalling system, comprising of the endogenous cannabis-like ligands (endocannabinoids) anandamide (AEA) and 2-arachidonoylglycerol (2-AG), which derive from arachidonic acid. These bind to a family of G-protein-coupled receptors, called CB1 and CB2. The cannabinoid receptor 1 (CB1R) is distributed in brain areas associated with motor control, emotional responses, motivated behaviour and energy homeostasis. In the periphery, the same receptor is expressed in the adipose tissue, pancreas, liver, GI tract, skeletal muscles, heart and the reproduction system. The CB2R is mainly expressed in the immune system regulating its functions. Endocannabinoids are synthesized and released upon demand in a receptor-dependent way. They act as retrograde signalling messengers in GABAergic and glutamatergic synapses and as modulators of postsynaptic transmission, interacting with other neurotransmitters. Endocannabinoids are transported into cells by a specific uptake system and degraded by the enzymes fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL). The ECS is involved in various pathophysiological conditions in central and peripheral tissues. It is implicated in the hormonal regulation of food intake, cardiovascular, gastrointestinal, immune, behavioral, antiproliferative and mammalian reproduction functions. Recent advances have correlated the ECS with drug addiction and alcoholism. The growing number of preclinical and clinical data on ECS modulators is bound to result in novel therapeutic approaches for a number of diseases currently treated inadequately. The ECS dysregulation has been correlated to obesity and metabolic syndrome pathogenesis. Rimonabant is the first CB1 blocker launched to treat cardiometabolic risk factors in obese and overweight patients. Phase III clinical trials showed the drug’s ability to regulate intra-abdominal fat tissue levels, lipidemic, glycemic and inflammatory parameters. However, safety conerns have led to its withrawal. The role of endocannabinoids in mammalian reproduction is an emerging research area given their implication in fertilization, preimplantation embryo and spermatogenesis. The relevant preclinical data on endocannabinoid signalling open up new perspectives as a target to improve infertility and reproductive health in humans.”

http://www.ncbi.nlm.nih.gov/pubmed/19675519