Tag Archives: antagonist

Peripheral CB1 cannabinoid receptor blockade improves cardiometabolic risk in mouse models of obesity

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Abstract

“Obesity and its metabolic consequences are a major public health concern worldwide. Obesity is associated with overactivity of the endocannabinoid system, which is involved in the regulation of appetite, lipogenesis, and insulin resistance. Cannabinoid-1 receptor (CB1R) antagonists reduce body weight and improve cardiometabolic abnormalities in experimental and human obesity, but their therapeutic potential is limited by neuropsychiatric side effects. Here we have demonstrated that a CB1R neutral antagonist largely restricted to the periphery does not affect behavioral responses mediated by CB1R in the brains of mice with genetic or diet-induced obesity, but it does cause weight-independent improvements in glucose homeostasis, fatty liver, and plasma lipid profile. These effects were due to blockade of CB1R in peripheral tissues, including the liver, as verified through the use of CB1R-deficient mice with or without transgenic expression of CB1R in the liver. These results suggest that targeting peripheral CB1R has therapeutic potential for alleviating cardiometabolic risk in obese patients.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2912197/

The Central Cannabinoid CB1 Receptor Is Required for Diet-Induced Obesity and Rimonabant’s Antiobesity Effects in Mice

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“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.”

http://www.nature.com/oby/journal/v19/n10/full/oby2011250a.html

The endocannabinoid system as a novel approach for managing obesity.

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“The recent discovery of the endocannabinoid system has led to the development of promising treatments for patients with obesity and associated cardiometabolic risk factors. Basic research has demonstrated that the endocannabinoid system plays an integral role in the regulation of food intake, metabolism, and storage. Research with the endocannabinoid receptor antagonist rimonabant has demonstrated statistically significant improvements in body weight, fasting insulin levels, glucose tolerance, high-density lipoprotein cholesterol levels, serum triglyceride levels, and waist circumference, compared with placebo. Rimonabant has also produced statistically significant improvements in inflammatory markers. Research with rimonabant has demonstrated sustained efficacy for as long as 2 years when used in conjunction with a reduced-calorie diet and moderate physical activity. Rimonabant is the first cannabinoid receptor 1 antagonist to be marketed in Europe and the first to file an New Drug Application in the United States. It may provide a novel therapeutic strategy for the treatment of patients with obesity and associated cardiometabolic risk factors.”

http://www.ncbi.nlm.nih.gov/pubmed/17784530

The challenge of treating obesity: the endocannabinoid system as a potential target.

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“Obesity and cardiometabolic risk, or the metabolic syndrome, continue to be major public health concerns. To date, treatment with lifestyle and pharmacotherapy interventions has resulted in limited efficacy in reversing the upward trend in this present-day health crisis. Research reveals that a modest 5% to 10% weight loss results in substantial improvement in health. While obtaining modest weight loss is often achievable, maintaining lost weight is challenging. Research has recently improved our understanding of several endogenous pathways that influence body weight regulation and disease risk. The endocannabinoid system has been found to regulate appetite and energy expenditure, as well as lipid and glucose metabolism. Interest in blocking stimulation of this pathway to aid weight loss and reduce cardiometabolic risk factor development is an area of interest and research. This article reviews the mechanisms by which the endocannabinoid system is believed to influence body weight regulation and cardiometabolic risk factors, as well as the results of clinical trials investigating the safety and efficacy of a selective cannabinoid-1 receptor antagonist (rimonabant). Clinical trials investigating rimonabant treatment resulted in substantial reductions in body weight and markers for cardiometabolic risk in study participants. However, increases in adverse events were reported in the drug-treated group. Data regarding long-term benefit and adverse events from rimonabant treatment are being collected in several ongoing clinical trials. Rimonabant is currently available in 42 countries, but has not received United States Food and Drug Administration approval. Food and nutrition professionals play a pivotal role in tackling the current obesity crisis; it is essential that they understand the many physiological mechanisms regulating body weight. Emerging research data reveals pathways that influence appetite and energy metabolism, and this knowledge may form the foundation for new clinical treatment options for obese individuals.”

http://www.ncbi.nlm.nih.gov/pubmed/18442506