Elevated endocannabinoid plasma levels are associated with coronary circulatory dysfunction in obesity

Aims Aim of this study was to evaluate a possible association between endocannabinoid (EC) plasma levels, such as anandamide (AEA) and 2-arachidonoylglycerol (2-AG), and coronary circulatory function in obesity. Methods and results Myocardial blood flow (MBF) responses to cold pressor test (CPT) and during pharmacological vasodilation with dipyridamole were measured with 13N-ammonia PET/CT. Study participants (n ¼ 77) were divided into three groups based on their body mass index (BMI, kg/m2): control group 20≤ BMI ,25 (n ¼ 21); overweight group, 25≤ BMI ,30 (n ¼ 26); and obese group, BMI ≥30 (n ¼ 30). Anandamide plasma levels, but not 2-AG plasma levels, were significantly elevated in obesity as compared with controls, respectively [0.68 (0.53, 0.78) vs. 0.56 (0.47, 0.66) ng/mL, P ¼ 0.020, and 2.2 (1.21, 4.59) vs. 2.0 (0.80, 5.90) ng/mL, P ¼ 0.806)]. The endothelium-related change in MBF during CPT from rest (DMBF) progressively declined in overweight and obese when compared with control group [0.21 (0.10, 0.27) and 0.09 (20.01, 0.15) vs. 0.26 (0.23, 0.39) mL/g/min; P ¼ 0.010 and P ¼ 0.0001, respectively). Compared with controls, hyperaemic MBFs were significantly lower in overweight and obese individuals [2.39 (1.97, 2.62) vs. 1.98 (1.69, 2.26) and 2.10 (1.76, 2.36); P ¼ 0.007 and P ¼ 0.042, respectively)]. In obese individuals, AEA and 2-AG plasma levels were inversely correlated with DMBF to CPT (r ¼ 20.37, P ¼ 0.046 and r ¼ 20.48, P ¼ 0.008) and hyperaemic MBFs (r ¼ 20.38, P ¼ 0.052 and r ¼ 20.45, P ¼ 0.017), respectively. Conclusions Increased EC plasma levels of AEA and 2-AG are associated with coronary circulatory dysfunction in obese individuals. This observation might suggest increases in EC plasma levels as a novel endogenous cardiovascular risk factor in obesity, but needing further investigations