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Improvement in Coronary Circulatory Function in Morbidly Obese Individuals After Gastric Bypass-Induced Weight Loss: Relation to Alterations in Endocannabinoids and Adipocytokines
Study Questions:
Do surgical gastric bypass-induced weight loss and related changes in endocannabinoids and adipocytokine plasma levels affect coronary circulatory dysfunction?
Methods:
In a prospective, baseline, and longitudinal study, coronary circulatory function was assessed with 13N-ammonia and positron emission tomography/computed tomography (PET/CT) by measuring myocardial blood flow at rest and its response to vasomotor stress in obese individuals (body mass index [BMI] ≥40 kg/m2) without arterial hypertension, hypercholesterolemia, smoking, and diabetes mellitus before and after a follow-up of at least 12 months after gastric bypass surgery as a weight reduction treatment. The standard operation involved Roux-en-Y gastric bypass surgery with an isolated gastric pouch. In addition, myocardial blood flow values were compared with those in 18 healthy, normal weight, age- and gender-matched controls who served as reference to define the normal range of coronary circulatory function.
Results:
A total of 18 morbidly obese individuals were studied. Median follow-up after gastric bypass was 22 months. Gastric bypass intervention decreased BMI from a median of 44.8 (interquartile range: 43.3, 48.2) to 30.8 (27.3, 34.7) kg/m2 (p < 0.0001). This decrease in BMI was accompanied by a marked improvement in endothelium-related change in myocardial blood flows to cold presser test and hyperaemic myocardial blood flows, respectively [0.34 (0.18, 0.41) from 0.03 (-0.08, 0.15) ml/g/min, p = 0.002; and 2.51 (2.17, 2.64) from 1.53 (1.39, 2.18) ml/g/min, p <0.001]. There was an inverse correlation between decreases in plasma concentrations of the endocannabinoids anandamide and improvement in change myocardial blood flows to cold presser test (r = -0.59, p = 0.009), while increases in adiponectin plasma levels correlated positively with hyperaemic myocardial blood flows (r = 0.60, p = 0.050). Conversely, decreases in leptin plasma concentrations were not observed to correlate with the improvement in coronary circulatory function (r = 0.22, p = 0.400, and r = -0.31, p = 0.250).
Conclusions:
The investigators concluded that gastric bypass-related reduction of BMI in morbidly obese individuals beneficially affects coronary circulatory dysfunction. The dysbalance between endocannabinoids and adipocytokines appears to be an important determinant of coronary circulatory function in obesity.
Perspective:
These data provide unique information regarding weight loss associated with gastric bypass surgery; in particular, such weight loss is associated with improvements in coronary endothelial function. Replication in larger cohorts is recommended.
Keywords: Adipokines, Body Mass Index, Gastric Bypass, Morbidity, Weight Loss, Obesity, Hypercholesterolemia, Endocannabinoids, Positron-Emission Tomography
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