Circulating Endocannabinoids Are Reduced Following Bariatric Surgery and Associated with Improved Metabolic Homeostasis in Humans
The endocannabinoid (eCB) system plays a key role in the development of obesity and its comorbidities. Limited information exists on the changes in circulating eCBs following bariatric surgery.
This study aims to (i) assess the circulating levels of eCBs and related molecules and (ii) examine the association between their levels and numerous clinical/metabolic features pre- and post-operatively.
Sixty-five morbidly obese patients (age 42.78 ± 9.27 years; BMI 42.00 ± 5.01 kg/m2) underwent laparoscopic sleeve gastrectomy (LSG) surgery, and were followed up for 12 months. Data collected included anthropometrics and metabolic parameters. The serum levels of the eCBs, 2-arachidonoylglycerol (2-AG), anandamide (AEA); and their related molecules, arachidonic acid (AA) and oleoylethanolamine (OEA) were measured by liquid chromatography-mass spectrometry.
Levels of 2-AG, AEA, and AA were reduced post operatively with no differences in serum OEA levels. The delta changes in eCB levels between pre- and post-operation were correlated with the delta of different metabolic parameters. Positive correlations were found between delta AA and waist circumference (WC) (r = 0.28, P < 0.05), free fat mass (r = 0.26, P < 0.05), SteatoTest score (r = 0.45, P < 0.05), and ALT (r = 0.32, P < 0.05). Delta AEA levels positively correlated with WC (r = 0.30, P < 0.05). Delta 2-AG levels positively correlated with total cholesterol (r = 0.27, P < 0.05), triglycerides (r = 0.55, P < 0.05), and SteatoTest score (r = 0.27, P < 0.05). Delta OEA levels negatively correlated with fasting glucose levels (r = − 0.27, P < 0.05).
This study provides compelling evidence that LSG surgery induces reductions in the circulating 2-AG, AEA, and AA levels, and that these changes are associated with clinical benefits related to the surgery including reduced fat mass, hepatic steatosis, glucose, and improved lipid profile.
KeywordsEndocannabinoids Laparoscopic sleeve gastrectomy Obesity Metabolic parameters
This study was supported (in part) by a grant no. 3-10470 from the Chief Scientist’s Office of the Ministry of Health, Israel, to O.S. and a grant from the Israeli Science Foundation (ISF; 617/14) to J.T. The funding source did not play a role in the design, conduct, and analysis of the study or the decision to submit this manuscript for publication.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
All procedures performed in this study were approved by the institutional research committees in both participating hospitals and in accordance with the ethical standards of the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The study was preregistered in the NIH registration website (TRIAL no. NCT01922830).
Statement of Informed Consent
Informed consent was obtained from all individual participants included in the study.
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