The endocannabinoid system and cardiometabolic risk: Effects of CB1 receptor blockade on lipid metabolism

Cardiometabolic risk factors affect more than 47 million adults in the United States today. Although certain risk factors (e.g., obesity, dyslipidemia, hypertension, and hyperglycemia) contribute independently to the global risk, dyslipidemia is one of the most important risk factors for cardiovascular disease. Successful treatment requires a well-coordinated multifaceted approach, with commitment to a long-term program for disease management. Although initial attempts should focus on dietary changes and increased physical activity, most patients also need effective, safe, and well-monitored pharmacotherapy. Experimental studies have shown that overactivation of the endocannabinoid system-a physiologic signaling system involved in regulating energy intake, fatty acid synthesis and storage, and glucose and lipid metabolism-is associated with obesity, dyslipidemia, and insulin resistance. In clinical trials, selective blockade of CB1 receptors has resulted in substantial weight loss and significant improvement in lipid profiles. The effects of rimonabant, the first selective CB1 receptor blocker, were evaluated in 6600 obese or overweight adults who participated in one of 4 multicenter, placebo-controlled, randomized clinical trials for at least 1 year. Significant improvement in lipid profiles (specifically HDL and triglyceride levels and ratio of total cholesterol to HDL cholesterol) was seen in the 2503 patients taking rimonabant 20 mg/day, independent of its substantial effects on weight loss. No significant changes in LDL or total cholesterol were observed. Results of clinical trials with rimonabant are promising. Additional long-term controlled studies with appropriate follow-up are warranted to confirm the clinical potential of this drug, particularly its effects on dyslipidemia and other cardiovascular endpoints.