Rimonabant: A Cannabinoid Receptor Type 1 Blocker for Management of Multiple Cardiometabolic Risk Factors

Advances in cannabinoid receptors pharmacology: from receptor structural insights to ligand discovery

The medicinal and recreational uses of Cannabis sativa have been recognized for thousands of years. Today, cannabis-derived medicines are used to treat a variety of conditions, including chronic pain, epilepsy, multiple sclerosis, and chemotherapy-induced nausea. However, cannabis use disorder (CUD) has become the third most prevalent substance use disorder globally. Cannabinoid receptors are the primary targets that mediate the effects of cannabis and its analogs. Despite their importance, the mechanisms of modulation and the full therapeutic potential of cannabinoid receptors remain unclear, hindering the development of the next generation of cannabinoid-based drugs. This review summarizes the discovery and medicinal potential of phytocannabinoids and explores the distribution, signaling pathways, and functional roles of cannabinoid receptors. It also discusses classical cannabinoid drugs, as well as agonists, antagonists, and inverse agonists, which serve as key therapeutic agents. Recent advancements in the development of allosteric drugs are highlighted, with a focus on positive and negative allosteric modulators (PAMs and NAMs) that target CB1 and CB2 receptors. The identification of multiple allosteric sites on the CB1 receptor and the structural basis for allosteric modulation are emphasized, along with the structure-based discovery of ago-BAMs for CB1. This review concludes by examining the future potential of allosteric modulators in cannabinoid drug development, noting that ongoing progress in cannabinoid-derived drugs continues to open new avenues for therapeutic use and paves the way for future research into their full medicinal potential.

Contemporary nationwide trends in major adverse cardiovascular events in young cannabis users without concomitant tobacco, alcohol, cocaine use

BACKGROUND

Cannabis use has increased among young individuals in recent years. Although dependent cannabis use disorder (CUD) has been associated with various cardiac events, its effects on young adults without concurrent substance use remain understudied.

AIM

To examine trends in hospitalizations for major adverse cardiac and cerebrovascular events (MACCE) in this cohort.

METHODS

We used the National Inpatient Sample (2016-2019) to identify hospitalized young individuals (18-44 years), excluding those with concurrent substance usage (tobacco, alcohol, and cocaine). They were divided into CUD+ and CUD-. Using International Classification of Diseases-10 codes, we examined the trends in MACCE hospitalizations, including all-cause mortality (ACM), acute myocardial infarction (AMI), cardiac arrest (CA), and acute ischemic stroke (AIS).

RESULTS

Of 27.4 million hospitalizations among young adults without concurrent substance abuse, 4.2% (1.1 million) had co-existent CUD. In CUD+ group, hospitalization rates for MACCE (1.71% vs 1.35%), AMI (0.86% vs 0.54%), CA (0.27% vs 0.24%), and AIS (0.49% vs 0.35%) were higher than in CUD- group (P < 0.001). However, rate of ACM hospitalizations was lower in CUD+ group (0.30% vs 0.44%). From 2016 to 2019, CUD+ group experienced a relative rise of 5% in MACCE and 20% in AMI hospitalizations, compared to 22% and 36% increases in CUD- group (P < 0.05). The CUD+ group had a 13% relative decrease in ACM hospitalizations, compared to a 10% relative rise in CUD- group (P < 0.05). However, when adjusted for confounders, MACCE odds among CUD+ cohort remain comparable between 2016 and 2019.

CONCLUSION

The CUD+ group had higher rates of MACCE, but the rising trends were more apparent in the CUD- group over time. Interestingly, the CUD+ group had lower ACM rates than the CUD- group.

Cannabinoids in Breast Cancer: Differential Susceptibility According to Subtype

Although cannabinoids have been used for centuries for diverse pathological conditions, recently, their clinical interest and application have emerged due to their diverse pharmacological properties. Indeed, it is well established that cannabinoids exert important actions on multiple sclerosis, epilepsy and pain relief. Regarding cancer, cannabinoids were first introduced to manage chemotherapy-related side effects, though several studies demonstrated that they could modulate the proliferation and death of different cancer cells, as well as angiogenesis, making them attractive agents for cancer treatment. In relation to breast cancer, it has been suggested that estrogen receptor-negative (ER-) cells are more sensitive to cannabinoids than estrogen receptor-positive (ER+) cells. In fact, most of the studies regarding their effects on breast tumors have been conducted on triple-negative breast cancer (TNBC). Nonetheless, the number of studies on human epidermal growth factor receptor 2-positive (HER2+) and ER+ breast tumors has been rising in recent years. However, besides the optimistic results obtained thus far, there is still a long way to go to fully understand the role of these molecules. This review intends to help clarify the clinical potential of cannabinoids for each breast cancer subtype.

Brugada Electrocardiogram Pattern Induced by Recreational Delta-8-Tetrahydrocannabinol (THC): A Case Report

Brugada electrocardiogram (ECG) pattern describes a characteristic right bundle branch block (RBBB) appearance with persistent ST-segment elevation in precordial leads V1 to V3, often associated with Brugada syndrome, a genetic sodium channelopathy, in the absence of ischemic or structural heart disease. Known triggers such as fever, electrolyte abnormalities, medications, or recreational drugs may elicit such an ECG pattern without a clear clinical significance yet creating a dilemma for clinicians providing care in the urgent setting. We present a case of reversible Brugada electrocardiogram pattern (BEP) after recreational use of delta-8-tetrahydrocannabinol (THC) and explore the need for further research on the safety of such an over-the-counter supplement.

L-Theanine regulates glutamine metabolism and immune function by binding to cannabinoid receptor 1

l-Theanine is a characteristic amino acid in tea with various effects including antioxidant and anti-inflammatory effects. Previously, most studies had reported that l-theanine regulates the immune function in vivo by inhibiting the expression of the inflammatory factors, but how l-theanine regulates the inflammatory factors' pathway is not known. In this study, we innovatively found the binding target of l-theanine in vivo-cannabinoid receptor 1, and demonstrated that l-theanine regulated the immune function and glutamine metabolism by competitively binding cannabinoid receptor 1. Mechanistically, l-theanine competitively binds cannabinoid receptor 1, leading to inhibition of cannabinoid receptor 1 activity, and regulates glutamine metabolism and immune function in normal and E44813-stressed rats. In normal rats, l-theanine inhibits ERK1/2 phosphorylation through Gβy by antagonizing cannabinoid receptor 1, thus affecting GS expression. From the point of view of immune signaling, after LTA antagonizes the activity of cannabinoid receptor 1, it relieves the inhibition of cannabinoid receptor 1 on COX-2 expression, downregulates Pdcd4 expression and NFκB, and ultimately enhances the expression of the anti-inflammatory factor IL-10. In E44813-stressed rats, l-theanine promotes the nuclear translocation of p-ERK1/2 by inhibiting the activity of cannabinoid receptor 1, and finally acts on GS. At the same time, it decreases the expression of the pro-inflammatory factor TNF-α and increases the expression of the anti-inflammatory factor IL-10 in stressed rats through the COX2-Pdcd4-NFκB-IL10 and TNFα pathways. In summary, these results demonstrate that l-theanine regulates glutamine metabolism and immune function by competitively binding to cannabinoid receptor 1.

Targeting the endocannabinoid system: a predictive, preventive, and personalized medicine-directed approach to the management of brain pathologies

Cannabis-inspired medical products are garnering increasing attention from the scientific community, general public, and health policy makers. A plethora of scientific literature demonstrates intricate engagement of the endocannabinoid system with human immunology, psychology, developmental processes, neuronal plasticity, signal transduction, and metabolic regulation. Despite the therapeutic potential, the adverse psychoactive effects and historical stigma, cannabinoids have limited widespread clinical application. Therefore, it is plausible to weigh carefully the beneficial effects of cannabinoids against the potential adverse impacts for every individual. This is where the concept of "personalized medicine" as a promising approach for disease prediction and prevention may take into the account. The goal of this review is to provide an outline of the endocannabinoid system, including endocannabinoid metabolizing pathways, and will progress to a more in-depth discussion of the therapeutic interventions by endocannabinoids in various neurological disorders.

Nicotine patch for cannabis withdrawal symptom relief: a randomized controlled trial

RATIONALE

Given that tetrahydrocannabinol (THC) and nicotine have similar effects on negative affect (NA), we hypothesized that a 7-mg nicotine patch (NP) would reduce NA-related cannabis (CAN) withdrawal symptoms in cannabis-dependent (CD) individuals who were not nicotine dependent.

OBJECTIVE

We sought to determine whether NP reduces NA across 15 days of CAN abstinence in two groups: non-tobacco smokers (NTS) and light tobacco smokers (LTS).

METHODS

CD participants (N = 127; aged 18-35) who used CAN at least 5 times/week for the past 12 + months were randomized to (1) NP or (2) a placebo patch (PP) and received $300 for sustained biochemically verified CAN abstinence. Of those randomly assigned, 52 of 63 NP, and 56 of 64 PP maintained biochemically verified CAN abstinence and 51 NP and 50 PP participants complied with all aspects of the study. Affect and other withdrawal symptoms were measured every 48 h across 15 days of CAN abstinence.

RESULTS

After controlling for age, tobacco use, baseline THC concentration, and baseline measurements of the dependent variable, NP reduced NA symptoms across the 15-day treatment relative to PP. Differences in NA and CAN withdrawal symptoms were not moderated by tobacco user status.

CONCLUSIONS

The findings provide the first evidence that NP may be able to attenuate NA-related withdrawal symptoms in individuals with cannabis use disorder who are not heavy users of tobacco or nicotine.

CLINICAL TRIALS REGISTRY

NCT01400243 http://www.clinicaltrials.gov.

Opportunities for cannabis in supportive care in cancer

Cannabis has the potential to modulate some of the most common and debilitating symptoms of cancer and its treatments, including nausea and vomiting, loss of appetite, and pain. However, the dearth of scientific evidence for the effectiveness of cannabis in treating these symptoms in patients with cancer poses a challenge to clinicians in discussing this option with their patients. A review was performed using keywords related to cannabis and important symptoms of cancer and its treatments. Literature was qualitatively reviewed from preclinical models to clinical trials in the fields of cancer, human immunodeficiency virus (HIV), multiple sclerosis, inflammatory bowel disease, post-traumatic stress disorder (PTSD), and others, to prudently inform the use of cannabis in supportive and palliative care in cancer. There is a reasonable amount of evidence to consider cannabis for nausea and vomiting, loss of appetite, and pain as a supplement to first-line treatments. There is promising evidence to treat chemotherapy-induced peripheral neuropathy, gastrointestinal distress, and sleep disorders, but the literature is thus far too limited to recommend cannabis for these symptoms. Scant, yet more controversial, evidence exists in regard to cannabis for cancer- and treatment-related cognitive impairment, anxiety, depression, and fatigue. Adverse effects of cannabis are documented but tend to be mild. Cannabis has multifaceted potential bioactive benefits that appear to outweigh its risks in many situations. Further research is required to elucidate its mechanisms of action and efficacy and to optimize cannabis preparations and doses for specific populations affected by cancer.

A commentary on the medicinal use of marijuana

Background

Lately, the number of people using marijuana in the USA has dramatically increased. In 2018, many states have legalized marijuana use for both medical and recreational purposes, thus exploring the evidence behind medical marijuana use became essential. Muslim majority countries enforce rigorous rules as marijuana has been a long-debated issue due to the stigma associated with its use as a treatment. Marijuana has a high beneficial effect in managing chronic pain in adults and relieving spasticity symptoms in multiple sclerosis, obstructive sleep apnea syndrome, and fibromyalgia. As well as, used as pain management, and as anti-emetic in treatment of chemotherapy-induced vomiting and nausea. Marijuana is requested from more than one-third of posttraumatic stress disorder patients due to its significant clinical improvement in nightmares and subsidence disorder symptoms.

Marijuana adversely affects the body’s resistance to many infections, compromising their immune response. Its recreational use has led to an increasing trend in the occurrence of major acute cardiovascular events as stroke, epilepsy, acute myocardial infarction, congestive heart failure, and arrhythmia.

Conclusion

Many countries started to allow medicinal use of marijuana due to its beneficial effect in managing chronic pain, spasticity symptoms in multiple sclerosis, obstructive sleep apnea syndrome, fibromyalgia, and posttraumatic stress disorder. But literature lacks benefit-harm analysis for marijuana usage in medicine. Therefore, evidence-based report of short- and long-term health effects of marijuana use—both harmful and beneficial effects—is crucial for further marijuana prescription in healthcare settings.

Countering the Modern Metabolic Disease Rampage With Ancestral Endocannabinoid System Alignment

When primitive vertebrates evolved from ancestral members of the animal kingdom and acquired complex locomotive and neurological toolsets, a constant supply of energy became necessary for their continued survival. To help fulfill this need, the endocannabinoid (eCB) system transformed drastically with the addition of the cannabinoid-1 receptor (CB1R) to its gene repertoire. This established an eCB/CB1R signaling mechanism responsible for governing the whole organism's energy balance, with its activation triggering a shift toward energy intake and storage in the brain and the peripheral organs (i.e., liver and adipose). Although this function was of primal importance for humans during their pre-historic existence as hunter-gatherers, it became expendable following the successive lifestyle shifts of the Agricultural and Industrial Revolutions. Modernization of the world has further increased food availability and decreased energy expenditure, thus shifting the eCB/CB1R system into a state of hyperactive deregulated signaling that contributes to the 21st century metabolic disease pandemic. Studies from the literature supporting this perspective come from a variety of disciplines, including biochemistry, human medicine, evolutionary/comparative biology, anthropology, and developmental biology. Consideration of both biological and cultural evolution justifies the design of improved pharmacological treatments for obesity and Type 2 diabetes (T2D) that focus on peripheral CB1R antagonism. Blockade of peripheral CB1Rs, which universally promote energy conservation across the vertebrate lineage, represents an evolutionary medicine strategy for clinical management of present-day metabolic disorders.

Sex differences in the cardiometabolic health of cannabis users with a psychotic illness

BACKGROUND

Growing evidence shows cannabis use is associated with lower rates of metabolic dysregulation. Despite cannabis impacting each sex differently, few studies have examined the metabolic profile of male and female cannabis users separately. Our aim was to investigate sex differences in the impact of cannabis use on metabolic syndrome in adults with psychotic illness.

METHOD

Data from 1078 men and 735 women interviewed in the second Australian national survey of psychosis were analyzed using multiple logistic regression to model separately, for each sex, the influence of no, occasional and frequent past-year cannabis use on metabolic syndrome, adjusting for potential covariates including antipsychotic medication, smoking, and physical activity.

RESULTS

The proportion of women and men with metabolic syndrome was 58.1% and 57.6% respectively. Unadjusted analyses showed frequent cannabis use was associated with significantly lower odds of metabolic syndrome for both sexes. In adjusted analyses, the association between metabolic syndrome and frequent cannabis use remained significant for men (AOR = 0.49, 95% CI = 0.31-0.78), but not for women (AOR = 0.68, 95% CI = 0.37-1.24). Frequent cannabis use was associated with lower odds of abdominal obesity, hypertension and elevated triglyceride levels in men only.

CONCLUSIONS

The differences we found suggest cannabinoid regulation of energy balance may be sex-dependent and highlight the importance of examining cannabis use in men and women separately. At the same time, the negative association between cannabis and psychosis onset and relapse should not be dismissed.

Recurrent STEMI Precipitated by Marijuana Use: Case Report and Literature Review

Marijuana abuse is rapidly growing and currently it is the most coimnon drug of abuse in the United States due to increased legalization for recreational and medicinal use. Delta 9-tetrahydrocannibol, the main psychoactive compound in marijuana, acts via the endocannabinoid system to elicit various cardiovascular physiological effects, and has been associated with many adverse cardiovascular effects such as acute coronary syndrome, arrhythmias, and sudden cardiac death that have previously been reported by our group and others. We present a case of a 30-year-old African-American male with no cardiovascular disease (CVD) risk factors with recurrent ST-segment elevation myocardial infarctions (STEMI) whose coronary angiography revealed recurrent 100% occlusion of the left anterior descending artery (LAD) in the setting of marijuana smoking. It was the patient's third STEMI with 100% occlusion of the LAD with each STEMI secondary to thrombosis of a different region of the LAD. Marijuana use was confirmed by urine toxicology screening at each STEMI presentation. Coronary angiography on multiple occasions was negative for stenosis of other epicardial coronary arteries, and coronary calcimn scoring was zero. Evaluation for other cardiovascular risk factors including family history of premature coronary artery disease, dyslipidemia, diabetes, and hypercoagulable disorders was negative. Further studies are required to elucidate the mechanisms of marijuana-associated coronary thrombosis and myocardial infarction.

Marijuana Use and Cardiovascular Disease

Marijuana is currently the most used illicit substance in the world. With the current trend of decriminalization and legalization of marijuana in the US, physicians in the US will encounter more patients using marijuana recreationally over a diverse range of ages and health states. Therefore, it is relevant to review marijuana's effects on human cardiovascular physiology and disease. Compared with placebo, marijuana cigarettes cause increases in heart rate, supine systolic and diastolic blood pressures, and forearm blood flow via increased sympathetic nervous system activity. These actions increase myocardial oxygen demand to a degree that they can decrease the time to exercise-induced angina in patients with a history of stable angina. In addition, marijuana has been associated with triggering myocardial infarctions (MIs) in young male patients. Smoking marijuana has been shown to increase the risk of MI onset by a factor of 4.8 for the 60 minutes after marijuana consumption, and to increase the annual risk of MI in the daily cannabis user from 1.5% to 3% per year. Human and animal models suggest that this effect may be due to coronary arterial vasospasm. However, longitudinal studies have indicated that marijuana use may not have a significant effect on long-term mortality. While further research is required to definitively determine the impact of marijuana on cardiovascular disease, it is reasonable to recommend against recreational marijuana use, especially in individuals with a history of coronary artery disorders.

The Role of Endocannabinoid System Blockade in the Treatment of the Metabolic Syndrome

This review considers the use of the first selective blocker of the cannabinoid receptor type 1, rimonabant, to reduce weight and improve cardiovascular disease risk factors in obese patients with metabolic syndrome or multiple cardiovascular disease risk factors. In 4 large trials-Rimonabant in Obesity (RIO)-Lipids, RIO-Europe, RIO-North America, and RIO-Diabetes-after 1 to 2 years of treatment, rimonabant (20 mg/day) led to a significantly greater weight loss and reduction in waist circumference compared with placebo. Treatment with rimonabant was also associated with other favorable changes, including better glycemic control in type 2 diabetes mellitus, improved lipid profile, reduced blood pressure, increased adiponectin levels, fall in high-sensitivity C-reactive protein concentrations, and an overall decrease in the prevalence of the metabolic syndrome. Initial experience with rimonabant shows that it is generally well tolerated with the most common side effect of mild nausea. Rimonabant may be a useful adjunct to lifestyle and behavior modification in the treatment of obese subjects with metabolic syndrome or multiple cardiometabolic risk factors.

Prevention of cardiovascular complications of the metabolic syndrome: focus on pharmacotherapy

The metabolic syndrome increases the risk of atherothrombotic cardiovascular disease (CVD) and diabetes. In turn, diabetes promotes the development of atheroma and is regarded as a coronary heart disease risk equivalent. A multifactorial therapeutic strategy is advocated for patients with the metabolic syndrome to improve cardiovascular risk factor profiles and to reduce the chances of developing type 2 diabetes. Individual components of the syndrome must be addressed using safe, efficacious, and cost-effective measures. There is general agreement that lifestyle modifications, including control of body weight, avoidance of central adiposity, adoption of an antiatherogenic diet, and regular physical activity, are crucial. However, as the magnitude of the individual components of the metabolic syndrome increases with time, lifestyle measures are often insufficient. An individual with metabolic syndrome will often require drug treatment for hyperglycemia, atherogenic dyslipidemia, and high blood pressure, together with antiplatelet therapy. Reducing the need for polypharmacy is an increasingly important consideration for clinicians and the pharmaceutical industry; to date, no single therapy has emerged that targets the root cause(s) of the syndrome. HMG-CoA reductase inhibitors are important agents that reduce CVD morbidity and mortality, in people with impaired fasting glucose or metabolic syndrome. Selective cannabinoid receptor antagonists appear promising because they improve or attenuate several key defects of the syndrome. Thiazolidinediones and metformin are presently licensed for treatment of type 2 diabetes but may prove to have a broader role in future. Novel insulin-sensitizing drugs are under investigation. Drugs that act to prevent or reverse endothelial dysfunction may be of particular utility in preventing cardiovascular disease, especially if initiated before tissue damage has become irreversible. Insulin therapy, which has antiinflammatory and endothelial protective properties, has been shown to reduce morbidity and mortality in high-risk nondiabetic patients during critical illness. Potential synergy between different classes of drugs with metabolic and/or cardiovascular protective properties merits further investigation.

Platelet activation in obesity and metabolic syndrome

Obesity is associated with increased cardiovascular disease. Metabolic syndrome (MS) identifies substantial additional cardiovascular risk beyond the individual risk factors, and is a powerful predictor of cardiovascular events even regardless of body mass index, thus suggesting a common downstream pathway conferring increased cardiovascular risk. Platelet hyper-reactivity/activation plays a central role to accelerate atherothrombosis and is the result of the interaction among the features clustering in obesity and MS: insulin resistance, inflammation, oxidative stress, endothelial dysfunction. Interestingly, the same pathogenic events largely account for the less-than-expected response to antiplatelet agents, namely low-dose aspirin. The proposed explanations for this phenomenon, besides underdosing of drug and/or reduced bioavailability, subsequent to excess of adipose tissue, include enhanced platelet turnover, leading to unacetylated COX-1 and COX-2 in newly formed platelets as a source of aspirin-escaping thromboxane formation; extraplatelet sources of thromboxane, driven by inflammatory triggers; and enhanced lipid peroxidation, activating platelets with a mechanism bypassing COX-1 acetylation or limiting COX-isozyme acetylation by aspirin. This review will address the complex interactions between platelets and the pathogenic events occurring in obesity and MS, trying to translate this body of mechanistic information into a clinically relevant read-out, in order to establish novel strategies in the prevention/treatment of atherothrombosis.

The role of insulin resistance in the pathogenesis of atherosclerotic cardiovascular disease: an updated review

Insulin resistance is the main pathologic mechanism that links the constellation of clinical, metabolic and anthropometric traits with increased risk for cardiovascular disease and type II diabetes mellitus. These traits include hyperinsulinemia, impaired glucose intolerance, endothelial dysfunction, dyslipidemia, hypertension, and generalized and upper body fat redistribution. This cluster is often referred to as insulin resistance syndrome. The progression of insulin resistance to diabetes mellitus parallels the progression of endothelial dysfunction to atherosclerosis leading to cardiovascular disease and its complications. In fact, insulin resistance assessed by homeostasis model assessment (HOMA) has shown to be independently predictive of cardiovascular disease in several studies and one unit increase in insulin resistance is associated with a 5.4% increase in cardiovascular disease risk. This review article addresses the role of insulin resistance as a main causal factor in the development of metabolic syndrome and endothelial dysfunction, and its relationship with cardiovascular disease. In addition to this, we review the type of lifestyle modification and pharmacotherapy that could possibly ameliorate the effect of insulin resistance and reverse the disturbances in insulin, glucose and lipid metabolism.

Rimonabant inhibits TNF-α-induced endothelial IL-6 secretion via CB1 receptor and cAMP-dependent protein kinase pathway

AIM

To investigate whether rimonabant, a cannabinoid receptor antagonist, had inhibitory effects on inflammatory reactions in human umbilical vein endothelial cells (HUVEC).

METHODS

TNF-α-induced IL-6 production was measured by ELISA and effects on related signaling pathways were investigated by immunoblot analysis. Cellular cAMP level was measured using kinase-coupled luciferase reaction.

RESULTS

Rimonabant at 1 and 10 μmol/L significantly inhibited TNF-α-induced IL-6 production when added 15, 30 and 60 minutes before TNF-α treatment. Rimonabant also inhibited TNF-α-induced phosphorylation of IκB kinase (IKK) α/β and IκB-α degradation. ACEA, a cannabinoid receptor subtype 1 (CB1) agonist, added before rimonabant abolished the former effects of rimonabant. H-89, an inhibitor of cAMP-dependent protein kinase (PKA), abolished the inhibitory effects of rimonabant on TNF-α induced IL-6 production. Rimonabant also increased the phosphorylation of PKA regulatory subunit II (PKA-RII), implying the essential role of PKA activation in the inhibitory effects of rimonabant. Treatment with the phosphatidylinositol 3-kinase (PI3K) inhibitor, wortmannin did not abolish the inhibitory effects of rimonabant on TNF-α induced IL-6 production.

CONCLUSION

Rimonabant had anti-inflammatory effects on endothelial cells and inhibited TNF-α-induced IKKα/β phosphorylation, IκB-α degradation and IL-6 production in HUVEC. This effect was related to CB1 antagonism and PKA activation.

Management of the metabolic syndrome in cardiovascular disease

The main components of the metabolic syndrome (MS) are abdominal obesity, atherogenic dyslipidemia, raised blood pressure, insulin resistance with or without glucose intolerance, and proinflammatory and prothrombotic states. The clustering of these metabolic risk factors significantly increases the risk of type 2 diabetes and promotes vascular endothelial dysfunction, inflammation, and increased oxidative stress. The net result is an increase in the risk of atherosclerotic cardiovascular disease. Therefore, management of MS is of utmost importance, especially considering its rapidly increasing prevalence in a population with rising obesity rates and its significant cardiovascular implications. The primary management of this syndrome involves the correction of the underlying risk factors--obesity, physical inactivity, and an atherogenic diet--with lifestyle modifications including increased physical activity and dietary modification. Smoking cessation also should be encouraged. However, pharmacologic therapies are often required to address cardiovascular risk factors. These agents can be categorized broadly into 1) anorectic agents, 2) insulin-sensitizing agents, 3) statins, and 4) renin-angiotensin system antagonists. Emerging therapies include adipokines, endocannabinoid inhibitors, and metabolic modulators, such as perhexiline and trimetazidine. To date, these therapies have not been shown to normalize the metabolic and cardiovascular burden of MS, and there still is no single therapeutic agent for its management.

Targeting intermediary metabolism in the hypothalamus as a mechanism to regulate appetite

The central nervous system mediates energy balance (energy intake and energy expenditure) in the body; the hypothalamus has a key role in this process. Recent evidence has demonstrated an important role for hypothalamic malonyl CoA in mediating energy balance. Malonyl CoA is generated by the carboxylation of acetyl CoA by acetyl CoA carboxylase and is then either incorporated into long-chain fatty acids by fatty acid synthase, or converted back to acetyl-CoA by malonyl CoA decarboxylase. Increased hypothalamic malonyl CoA is an indicator of energy surplus, resulting in a decrease in food intake and an increase in energy expenditure. In contrast, a decrease in hypothalamic malonyl CoA signals an energy deficit, resulting in an increased appetite and a decrease in body energy expenditure. A number of hormonal and neural orexigenic and anorexigenic signaling pathways have now been shown to be associated with changes in malonyl CoA levels in the arcuate nucleus (ARC) of the hypothalamus. Despite compelling evidence that malonyl CoA is an important mediator in the hypothalamic ARC control of food intake and regulation of energy balance, the mechanism(s) by which this occurs has not been established. Malonyl CoA inhibits carnitine palmitoyltransferase-1 (CPT-1), and it has been proposed that the substrate of CPT-1, long-chain acyl CoA(s), may act as a mediator(s) of appetite and energy balance. However, recent evidence has challenged the role of long-chain acyl CoA(s) in this process, as well as the involvement of CPT-1 in hypothalamic malonyl CoA signaling. A better understanding of how malonyl CoA regulates energy balance should provide novel approaches to targeting intermediary metabolism in the hypothalamus as a mechanism to control appetite and body weight. Here, we review the data supporting an important role for malonyl CoA in mediating hypothalamic control of energy balance, and recent evidence suggesting that targeting malonyl CoA synthesis or degradation may be a novel approach to favorably modify appetite and weight gain.

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

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

Effect of antiobesity medications in patients with type 2 diabetes mellitus

Obesity is considered as a major health problem, as its prevalence continuously rises worldwide. One of the common health consequences of obesity is type 2 diabetes mellitus. Therefore, antiobesity management is a prerequisite in treating diabetic patients. Lifestyle modifications combined with pharmacological agents appear to be an effective approach. Sibutramine is a serotonin-noradrenaline reuptake inhibitor, which acts centrally by promoting the feeling of satiety and decreasing caloric intake, thus resulting in weight loss. A potential association with cardiovascular side effects has been noted. Orlistat, a gastric and pancreatic lipase inhibitor, also achieves significant weight loss and improves glycaemic status, but it has gastrointestinal side effects. Rimonabant, the first endocannabinoid CB1 antagonist, is associated with weight reduction and it improves diabetic parameters; nevertheless, it is associated with psychiatric disorders; indeed, a recently conducted safety review led to the temporal suspension of its commercialization. The above-mentioned medications seem to be currently useful agents for treating obesity in patients with type 2 diabetes mellitus. Other medications used for diabetes management, such as exenatide, liraglutide and pramlintide, have also shown body weight reduction. Ongoing research is needed to scrutinize the precise impact of these agents in the daily clinical practice of management of obesity in patients with type 2 diabetes mellitus.

Pharmacotherapy for smoking cessation

Tobacco dependence is a chronic relapsing disease that needs continuous treatment. In combination with behavioural support, pharmacotherapy is a proven key component for supporting smoking cessation. Effective drugs are available and recommended: nicotine replacement therapy (NRT), bupropion and varenicline. Much research into new pharmacological approaches is ongoing, combining 'old' and 'new' drugs and personalizing a pharmacological treatment for a single smoker/patient; other new medications and vaccines are in development. Overall, pharmacotherapy seems to have efficacy and cost-effectiveness in real life, thus physicians should become familiar with these medicines. Further efforts should be aimed at optimizing treatment management and increasing smoking cessation rates in the general population.

Smoking and suicide: a brief overview

This article provides a brief overview of the rationales, possible mechanisms and epidemiological data on the association of smoking, smoking cessation and cessation medications with suicide. Current smoking is reliably associated with suicide both in case-control and cohort studies. The three most plausible (but relatively untested) explanations for the association are that smokers have pre-existing conditions that increase their risk for suicide, smoking causes painful and debilitating conditions that might lead to suicide, and smoking decreases serotonin and monoamine oxidase levels. Stopping smoking appears to lead to major depression in some smokers; thus, it could induce suicide; however, smoking cessation has not been associated with suicide in the few studies available. Regulatory agencies have stated bupropion, rimonabant and varenicline appear to be associated with suicide; however, the data for these statements have not been presented in sufficient detail to assess their validity. Most prior data have come from post hoc analyses. Studies that a priori focus on understanding smoking and suicide are now needed.

Dyslipidemia and glucose dysregulation in overweight and obese patients

Inactivity and a sedentary lifestyle contribute to overweight, obesity, and cardiometabolic risk. Overweight and obesity can lead to metabolic abnormalities, insulin resistance, type 2 diabetes mellitus (DM), lipid disorders, and cardiovascular disease. Diet and exercise can effectively reverse overweight and obesity and their related comorbidities. Modest weight loss (5%-10%) and modest physical activity (30 minutes a day) are first-line recommendations for the prevention of type 2 DM. Clinical trials have demonstrated that insulin sensitivity can be improved and type 2 DM can be prevented through lifestyle modification and pharmacologic therapy, including antiobesity drugs, antidiabetic drugs, statins, and antihypertensive drugs. The endocannabinoid system plays an important role in regulating metabolism through its effects on food intake at the level of the hypothalamus and on body composition through peripheral effects on adipose tissue.

Endocannabinoids and liver disease. IV. Endocannabinoid involvement in obesity and hepatic steatosis

Endocannabinoids are endogenous lipid mediators that interact with the same receptors as plant-derived cannabinoids to produce similar biological effects. The well-known appetitive effect of smoking marijuana has prompted inquiries into the possible role of endocannabinoids in the control of food intake and body weight. This brief review surveys recent evidence that endocannabinoids and their receptors are involved at multiple levels in the control of energy homeostasis. Endocannabinoids are orexigenic mediators and are part of the leptin-regulated central neural circuitry that controls energy intake. In addition, they act at multiple peripheral sites including adipose tissue, liver, and skeletal muscle to promote lipogenesis and limit fat elimination. Their complex actions could be viewed as anabolic, increasing energy intake and storage and decreasing energy expenditure, as components of an evolutionarily conserved system that has insured survival under conditions of starvation. In the era of plentiful food and limited physical activity, pharmacological inhibition of endocannabinoid activity offers benefits in the treatment of obesity and its hormonal/metabolic consequences.

CB1 receptor blockade and its impact on cardiometabolic risk factors: overview of the RIO programme with rimonabant

Rimonabant, the first selective CB(1) receptor antagonist in clinical use, has been extensively investigated in the Rimonabant in Obesity (RIO) programme, comprising four 1-2 year placebo-controlled randomised clinical trials recruiting more than 6600 overweight/obese patients with or without co-morbidities. Rimonabant 20 mg daily consistently reduced body weight, waist circumference, triglycerides, blood pressure, insulin resistance and C-reactive protein levels, and increased HDL cholesterol concentrations in both non-diabetic and type-2 diabetic overweight/obese patients. Adiponectin levels were increased, an effect that correlated with HDL cholesterol augmentation, while small dense LDL cholesterol levels were decreased in patients receiving rimonabant 20 mg compared with those receiving placebo in RIO Lipids. Furthermore, in RIO Diabetes, a 0.7% reduction in glycated haemoglobin (HbA1c) levels was observed in metformin- or sulphonylurea-treated patients with type-2 diabetes, an effect recently confirmed in the 6-month SERENADE (Study Evaluating Rimonabant Efficacy in drug-NAive DiabEtic patients) trial in drug-naive diabetic patients. Almost half of metabolic changes occurred beyond weight loss, in agreement with direct peripheral effects. The positive effects observed after 1 year were maintained after 2 years. Rimonabant was generally well-tolerated, but with a slightly higher incidence of depressed mood disorders, anxiety, nausea and dizziness compared with placebo. In clinical practice, rimonabant has to be prescribed to the right patient, i.e. overweight/obese subjects with cardiometabolic risk factors and with no major depressive illness and/or ongoing antidepressive treatment, in order to both maximise efficacy and minimise safety issues. New trials are supposed to confirm the potential role of rimonabant in patients with abdominal adiposity, atherogenic dyslipidaemia and/or type-2 diabetes, i.e. at high cardiometabolic risk.

Cost-utility analysis of rimonabant in the treatment of obesity

OBJECTIVE

To estimate the incremental cost-utility ratio (ICUR) of rimonabant 20 mg/day in the treatment of obesity from a third-party payer's perspective.

METHODS

Pooled data from three randomized clinical trials were used to develop a decision tree with five treatment alternatives: 1- and 2-year treatment with rimonabant, 2-year placebo, 1-year rimonabant followed by 1-year placebo, and no treatment. All alternatives, except no treatment, were accompanied by lifestyle interventions. Treatment benefits included gains in quality-adjusted life-years (QALYs) and reduced incidence of type-2 diabetes mellitus and coronary heart disease (CHD). Drug acquisition cost was based on the average wholesale price of a comparator drug minus 15%. One-way and probabilistic sensitivity analyses were conducted to assess the stability of the base-case results.

RESULTS

One-year rimonabant and 1-year rimonabant followed by placebo were extensively dominated. Rimonabant for 2 years showed an average weight reduction of 8.49 kg, a body mass index reduction of 2.98 kg/m(2) and reduced waist circumference by 8.24 cm (placebo: 3.55 kg, 1.22 kg/m(2), 4.18 cm). Two-year rimonabant was associated with a relative reduction in the 5-year incidence of CHD by 7.15% and of diabetes by 9.28%. Incremental benefits (costs) were 0.0984 QALYs ($5209) compared to no treatment and 0.0581 QALYs ($4182) compared to placebo, producing ICURs of $52,936/QALY (95% confidence interval $39K-$69K) and $71,973/QALY ($51K-$98K), respectively.

CONCLUSIONS

Rimonabant combined with lifestyle interventions has the potential to decrease the rate of obesity-related comorbidities and improve health-related quality of life, albeit at considerable cost.

Identification of novel cannabinoid CB1 receptor antagonists by using virtual screening with a pharmacophore model

CB1 receptor antagonists have proven to be clinically effective in treating obesity and related disorders. We report here the identification of a novel class of azetidinone CB1 antagonists by using virtual screening methods. For this purpose, we developed a pharmacophore model based on known representative CB1 antagonists and employed it to screen a database of about a half million Schering-Plough compounds. We applied a stepwise filtering protocol based on molecular weight, compound availability, and a modified rule-of-five to reduce the number of hits. We then combined Bayesian modeling and clustering techniques to select a final set of 420 compounds for in vitro testing. Five compounds were found to have >50% inhibition at 100 nM in a CB1 competitive binding assay and were further characterized by using both CB1 and CB2 assays. The most potent compound has a CB1 K i of 53 nM and >5-fold selectivity against the CB2 receptor.

Emerging HDL-based therapies for atherothrombotic vascular disease

Statin therapy has been a significant advance in the management of dyslipidemia and atherothrombotic cardiovascular disease with a resultant 30% to 40% reduction in cardiovascular events; however, a significant number of events continue to occur in statin-treated patients, including in patients treated with high-dose statins targeted to achieve mean low-density lipoprotein cholesterol levels in the range of 60 to 80 mg/dL. Therefore, development and testing of new therapies that exploit the vascular protective effects of high-density lipoprotein (HDL) constitutes a rational and complementary approach. A number of HDL-based therapies are in various stages of development and testing. It is hoped that one or more of these new HDL-based therapies, if proven effective and safe, will become a part of our armamentarium against vaso-occlusive cardiovascular disease. A paradigm could emerge in which patients recovering from acute coronary syndromes and at high risk of recurrent events could be treated with rapid-acting HDL-based therapy, such as infusions of recombinant HDL or even HDL delipidation, followed by more sustained long-term HDL-based therapies, such as oral agents and perhaps even HDL-based gene therapy.

HDL-cholesterol modulation and its impact on the management of cardiovascular risk

There is strong epidemiological evidence that HDL-cholesterol (HDL-C) is an independent cardiovascular risk factor. A low HDL-C is a common finding in the general population, and is a feature of metabolic syndrome, the prevalence of which is increasing globally. The importance of HDL-C as a coronary risk factor is generally accepted, and has been incorporated into most of the commonly applied risk engines. There are several causes of a low HDL-C, including rare genetic abnormalities, and more common conditions associated with lifestyle and drug therapy. Not all of these are associated with an increased risk of coronary disease. A better understanding of HDL metabolism and the mechanisms by which it may exert its protective effects has revealed why this may be the case. New therapeutic targets have also been identified that may allow HDL-C to be raised in patients with low levels. However, good clinical endpoint studies are still required to enable the setting of absolute target values for HDL-C in patients at high cardiovascular risk.

Smoking cessation: lessons learned from clinical trial evidence

PURPOSE OF REVIEW

Cigarette smoking and exposure to secondhand smoke cause coronary heart disease. Cessation dramatically reduces the incidence of primary and secondary cardiac events. The review presents up-to-date information regarding nicotine dependence, recent findings related to its treatment, and recommendations for addressing smoking cessation for the primary and secondary prevention of coronary heart disease.

RECENT FINDINGS

Bans on smoking in public places are associated with significant reductions in the incidence of acute myocardial infarction. Counseling and pharmacotherapy (nicotine replacement therapy, bupropion) are proven, effective treatments for nicotine dependence. Clinical trials of two new pharmacotherapies, varenicline and rimonabant, have recently been reported. Varenicline is a safe and efficacious medication for smoking cessation, and has been approved in the US, Canada and Europe. Rimonabant has shown mixed results for smoking cessation and is undergoing further evaluation.

SUMMARY

All patients should be screened for tobacco use. Clinicians can effectively treat nicotine dependence in the general population using counseling and first-line pharmacotherapies (nicotine replacement therapy, bupropion, varenicline). These same treatments, with some modification, are appropriate for smokers with coronary heart disease; however, brief interventions without follow-up are not effective in this population. For smokers with coronary heart disease, the best time to intervene may be during hospitalization.

The importance of beta-cell management in type 2 diabetes

Despite intervention with effective oral glucose-lowering agents, most patients with type 2 diabetes will experience a gradual loss of glycaemic control. Irrespective of underlying levels of insulin resistance, the progressive failure and loss of beta-cells are ultimately responsible for the onset of frank type 2 diabetes. The mechanisms responsible for loss of beta-cell function are likely to be multifactorial, but may involve toxicity because of elevated glucose and/or lipid levels, increased secretory demand because of insulin resistance, amyloid deposition and altered levels of cytokines. Preservation of beta-cell function is now gaining recognition as a critical target in the management of type 2 diabetes. For patients with frank type 2 diabetes, preservation of beta-cell function has the potential to reduce or stabilise the progression of type 2 diabetes and to decrease the need for additional oral glucose-lowering agents and/or insulin therapy. There is a growing body of animal/preclinical evidence for improved and preserved beta-cell function with current glucose-lowering agents, such as the thiazolidinediones, metformin and the glucagon-like peptide-1 analogue, exenatide. Clinical studies incorporating indirect measures of beta-cell function also support a protective effect with some agents. A number of novel therapies that are currently under investigation may also offer beta-cell structural and functional protection, including dipeptidyl peptidase IV inhibitors and cannabinoid receptor type 1 blockers. Emerging evidence from interventional trials suggests that both intensive lifestyle changes and pharmacotherapy can delay or possibly prevent the onset of type 2 diabetes in high-risk individuals. For patients newly diagnosed with type 2 diabetes, early and aggressive intervention strategies that combine maximal glucose-lowering efficacy alongside potential beta-cell preserving properties may provide an opportunity to delay or prevent progression of the disease.

Cannabinoid-1 receptor antagonists in type-2 diabetes

Type-2 diabetes is closely related to abdominal obesity and is generally associated with other cardiometabolic risk factors, resulting in a risk of major cardiovascular disease. Several animal and human observations suggest that the endocannabinoid system is over-active in the presence of abdominal obesity and/or diabetes. Both central and peripheral endocannabinoid actions, via the activation of CB1 receptors, promote weight gain and associated metabolic changes. Rimonabant, the first selective CB(1) receptor blocker in clinical use, has been shown to reduce body weight, waist circumference, triglycerides, blood pressure, insulin resistance index and C-reactive protein levels, and to increase high-density lipoprotein (HDL) cholesterol and adiponectin concentrations in both non-diabetic and diabetic overweight/obese patients. In addition, a 0.5-0.7% reduction in HbA1c levels was observed in metformin- or sulphonylurea-treated patients with type-2 diabetes and in drug-naïve diabetic patients. Almost half of the metabolic changes, including HbA1c reduction, could not be explained by weight loss, suggesting that there are direct peripheral effects. Rimonabant was generally well-tolerated, and the safety profile was similar in diabetic and non-diabetic patients, with a higher incidence of depressed mood disorders, nausea and dizziness. In conclusion, the potential role of rimonabant in overweight/obese patients with type-2 diabetes and at high risk of cardiovascular disease deserves much consideration.

A possible role for the endocannabinoid system in the neurobiology of depression

The present review synthetically describes the currently advanced hypotheses for a neurobiological basis of depression, ranging from the classical monoaminergic to the more recent neurotrophic hypothesis. Moreover, the Authors review the available preclinical and clinical evidence suggesting a possible role for the endocannabinoid system in the physiopathology of depression. Indeed, in spite of the reporting of conflicting results, the pharmacological enhancement of endocannabinoid activity at the CB1 cannabinoid receptor level appears to exert an antidepressant-like effect in some animal models of depression. On the contrary, a reduced activity of the endogenous cannabinoid system seems to be associated with the animal model of depression, namely the chronic mild stress model. Moreover, a few studies have reported an interaction of antidepressants with the endocannabinoid system. With regard to clinical studies, several authors have reported an alteration of endocannabinoid serum levels in depression, while post mortem studies have demonstrated increased levels of endocannabinoids associated to a concomitant hyperactivity of CB1 receptor in the prefrontal cortex of suicide victims. No clinical trials carried out using cannabinoids in the treatment of affective disorders have been published to date, although anecdotal reports have described both antidepressant and antimanic properties of cannabis as well as the ability of cannabis to induce mania that has also been documented. These findings are discussed, leading us to conclude that, although data available are sufficient to suggest a possible involvement of the endogenous cannabinoid system in the neurobiology of depression, additional studies should be performed in order to better elucidate the role of this system in the physiopathology of depression.

High-density lipoprotein cholesterol and residual cardiometabolic risk in metabolic syndrome

It has long been recognized that elevated levels of low-density lipoprotein cholesterol (LDL-C) increase the risk of cardiovascular disease (CVD) and that pharmacologic therapy to decrease LDL-C significantly reduces cardiovascular events. Despite the effectiveness of statins for CVD risk reduction, even optimal LDL-lowering therapy alone fails to avert approximately 60% to 70% of CVD cases, and the incidence of CVD mortality continues to grow. A low plasma concentration of high-density lipoprotein cholesterol (HDL-C) is also associated with increased risk of CVD and is 1 component of metabolic syndrome, a cluster of interrelated CVD risk factors. HDL stimulates reverse cholesterol transport from the peripheral tissues to the liver for removal from the body, prevents deleterious effects of LDL on endothelial function, acts as an antioxidant, and also possesses anti-inflammatory, antithrombotic, and antiapoptotic effects. Some of the treatments that increase HDL-C concentrations have been shown to reduce atheroma volume and may prevent the formation of new atherosclerotic lesions, thereby reducing the risk of CVD. For these reasons, increasing HDL-C concentrations has become a potentially attractive therapeutic target for individuals who are at increased risk of CVD, including those with metabolic syndrome. Traditional strategies to increase HDL-C include the use of niacin, statins, and fibric acid derivatives. Pharmacotherapies that have recently been developed and are currently being evaluated include inhibition of the enzyme cholesteryl ester transfer protein (CETP) and antagonism of the endocannabinoid CB1 receptor. Initial studies of CETP inhibitors suggest that these agents may markedly increase HDL-C concentrations. Clinical trials with rimonabant, a CB1 receptor antagonist, have demonstrated significant weight loss as well as increased HDL-C levels and reduced triglyceride levels.

Management of Obesity in Patients with Peripheral Arterial Disease

Obesity is a major risk factor for cardiovascular disorders, including peripheral arterial disease. This review outlines the evidence for a 6-step process for the management of obesity, starting with identifying the degree and type of obesity, followed by target setting, life style and behavioural changes, imposed hypocaloric diet and physical activity, pharmacological treatment and consideration of eating disorders and/or bariatric surgery.

Interactions between microvascular and macrovascular disease in diabetes: pathophysiology and therapeutic implications

Convention partitions the complications of diabetes into two main subtypes. First are the diabetes-specific microvascular complications of retinopathy, nephropathy and neuropathy; second are the atherothrombotic macrovascular complications that account for the majority of premature deaths. Pathological interactions between microvascular and macrovascular complications, for example, nephropathy and macrovascular disease, are common. Similar mechanisms and shared risk factors drive the development and progression of both small and large vessel disease. This concept has therapeutic implications. Mounting evidence points to the need for multifactorial strategies to prevent vascular complications in subjects with diabetes and/or the metabolic syndrome. We advocate a combined therapeutic approach that addresses small and large vessel disease. Preferential use should be made of drug regimens that (i) maximize vascular protection, (ii) reduce the risk of iatrogenic vascular damage and (iii) minimize the increasing problem of polypharmacy.

Cannabinoid receptors in acute and chronic complications of atherosclerosis

Atherosclerosis is a chronic inflammatory disease that is the primary cause of myocardial infarction and stroke, which occur after sudden thrombotic occlusion of an artery. A growing body of evidence suggests that cannabinoid signalling plays a fundamental role in atherosclerosis development and its clinical manifestations. Thus, CB2 receptors are protective in myocardial ischaemia/reperfusion and implicated in the modulation of chemotaxis, which is crucial for the recruitment of leukocytes during inflammation. Delta-9-Tetrahydrocannabinol (THC)-mediated activation has been shown to inhibit atherosclerotic plaque progression in a CB2 dependent manner. Although CB1 and CB2 expression has been reported on platelets, their involvement in thrombus formation is still controversial. While several reports suggest that CB1 receptors may have a relevant role in neuroprotection after ischaemic stroke, recent studies show the protective effects in various forms of neuroprotection are not related to CB1 stimulation, and a protective role of CB1 blockade has also been reported. In addition, vascular and myocardial CB1 receptors contribute to the modulation of blood pressure and heart rate. It is tempting to suggest that pharmacological modulation of the endocannabinoid system is a potential novel therapeutic strategy in the treatment of atherosclerosis. For these purposes, it is important to better understand the complex mechanisms of endocannabinoid signalling and potential consequences of its pharmacological modulation, as it may have both pro- and anti-atherosclerotic effects.

Endocannabinoid System and Cardiometabolic Risk

The increasing prevalence of overweight and obesity counteracts the favorable advances of risk factor management achieved for cardiovascular disease (CVD) prevention. Obese and overweight individuals are at increased risk for CVDs and diabetes mellitus, a risk pattern called "cardiometabolic risk." There is a growing interest concerning the role of the endocannabinoid system in energy metabolism and how blockade of cannabinoid receptors (CB(1)) may optimize fat distribution, insulin sensitivity, and blood lipids to improve cardiovascular risk profile.

Genetic forms of the cardiometabolic syndrome: what can they tell the clinician?

A well-worn medical aphorism states that "when you hear hoof beats, think of a horse and not a zebra." When applying this principle to the cardiometabolic syndrome (CMS), the horse would be represented by the prevalent CMS phenotype that affects approximately 30% of individuals in Westernized societies, while the zebra is represented by very rare conditions--such as lipodystrophy syndromes--that share some features with the more prevalent CMS. For instance, familial partial lipodystrophy types 2 and 3 result from heterozygous mutations in LMNA, encoding nuclear lamin A/C, and in PPARG, encoding peroxisome proliferator-activated receptor (PPAR)-gamma, respectively. Patients with either subtype of partial lipodystrophy exhibit an increased ratio of central to peripheral fat stores, dysglycemia, dyslipidemia, and hypertension, with predisposition for developing insulin-resistant diabetes and atherosclerosis end points. Sometimes, however, the zebra serves as a model that can help us understand the horse, so that the rare partial lipodystrophies might offer some insight into pathogenesis and treatment of the more prevalent CMS.

Endocannabinoid system and pathophysiology of adipogenesis: current management of obesity

The endocannabinoids are now known as novel and important regulators of energy metabolism and homeostasis. The endocrine functions of white adipose are chiefly involved in the control of whole-body metabolism, insulin sensitivity and food intake. Adipocytes produce hormones, such as leptin and adiponectin, that can improve insulin resistance or peptides, such as TNF-α, that elicit insulin resistance. Adipocytes express specific receptors, such as peroxisome proliferator-activated receptor (PPAR)-γ, which serve as adipocyte targets for insulin sensitizers such as thiazolidinediones. Recently, endocannabinoids and related compounds were identified in human fat cells. The endocannabinoid system consists primarily of two receptors, cannabinoid (CB)1 and CB2, their endogenous ligands termed endocannabinoids and the enzymes responsible for ligand biosynthesis and degradation. The endocannabinoids 2-arachidonylglycerol and anandamide or N-arachidonoylethanolamine increase food intake and promote weight gain in animals. Rimonabant, a selective CB1 blocker, reduces food intake and body weight in animals and humans.

Blocking the Cannabinoid Receptors: Drug Candidates and Therapeutic Promises

The CB1 and CB2 cannabinoid receptors have been described as two prime sites of action for endocannabinoids. Both the localization and pharmacology of these two G-protein-coupled receptors are well-described, and numerous selective ligands have been characterized. The physiological effects of Cannabis sativa (cannabis) and a throughout study of the endocannabinoid system allowed for the identification of several pathophysiological conditions--including obesity, dyslipidemia, addictions, inflammation, and allergies--in which blocking the cannabinoid receptors might be beneficial. Many CB1 receptor antagonists are now in clinical trials, and the results of several studies involving the CB1 antagonist lead compound rimonabant (SR141716A) are now available. This review describes the pharmacological tools that are currently available and the animal studies supporting the therapeutic use of cannabinoid receptor antagonists and inverse agonists. The data available from the clinical trials are also discussed.