The Effect of Mifepristone (RU486) on the Endocannabinoid System in Human Plasma and First- Trimester Trophoblast of Women Undergoing Termination of Pregnancy Tülay Karasu, Timothy H. Marczylo, Emma L. Marczylo, Anthony H. Taylor, Emeka Oloto, and Justin C. Konje Endocannabinoid Research Group (T.K., T.H.M., A.H.T., J.C.K.), Reproductive Sciences, Leicester Royal Infirmary, Leicester, Leicestershire, LE2 7LX, United Kingdom; Systems Toxicology (E.L.M.), Medical Research Council Toxicology Unit, Hodgkin Building, Lancaster Road, Leicester, LE1 9HN, United Kingdom; and Contraception, Sexual, and Reproductive Health Services (E.O.), University Hospitals of Leicester National Health Service (NHS) Trust, St Peters Health Centre, Leicester, LE2 0TA, United Kingdom Introduction: High anandamide (AEA) concentrations are detrimental for implantation and early pregnancy. Progesterone, essential for pregnancy, may keep AEA levels low by increasing fatty acid amide hydrolase (FAAH) expression. Here the effect of RU486, a P4 antagonist used to initiate medical termination of pregnancy (MTOP), on plasma AEA concentrations and the endocannabi- noid system (ECS) in trophoblasts was examined. Objective: Quantification of the endocannabinoid concentrations and expression of the ECS in tro- phoblast tissue of MTOP women and women undergoing surgical termination of pregnancy (STOP). Design and Setting: A prospective study at the University Hospitals of Leicester National Health Service Trust. Patients and Methods: AEA, N-oleoylethanolamine (OEA), and N-palmitolylethanolamine (PEA) concentrations in trophoblast tissues and blood samples from 68 MTOP and 15 STOP were analyzed by ultra-high-performance liquid chromatography-tandem mass spectrometry. ECS expression was determined by immunohistochemistry, quantitative RT-PCR, and Western blotting. Results: Concentrations of AEA, OEA, and PEA were significantly higher in MTOP than STOP tro- phoblasts (P = .0062, P = .016, and P = .0029, respectively), whereas no significant differences in plasma AEA, OEA, and PEA concentrations were observed even though plasma AEA and PEA concentrations were significantly (P = .005 and P = .025, respectively) increased the day after RU486 administration in women undergoing MTOP. Changes in the immunohistochemical densities of the AEA modifying enzymes N-acylphophatidylethanolamine-phospholipase D (NAPE-PLD) and FAAH, and the cannabinoid receptors (CB1 and CB2) were observed with increased NAPE-PLD, FAAH, and CB1 expression seen in the trophoblast of MTOP patients. Conclusions: Trophoblast after MTOP demonstrated high AEA concentrations with increased ex- pression of NAPE-PLD, FAAH, and CB1. (J Clin Endocrinol Metab 99: 871– 880, 2014) ISSN Print 0021-972X ISSN Online 1945-7197 Printed in U.S.A. Copyright © 2014 by the Endocrine Society Received July 22, 2013. Accepted December 3, 2013. First Published Online December 17, 2013 Abbreviations: AEA, anandamide; BMI, body mass index; CB1, CB2, cannabinoid recep- tors; ECS, endocannabinoid system; FAAH, fatty acid amide hydrolase; MTOP, medical termination of pregnancy; NAE, N-acylethanolamines; NAPE-PLD, N-acylphophatidyletha- nolamine-phospholipase D; OEA, N-oleoylethanolamine; P4, progesterone; PEA, N-palmi- tolylethanolamine; PG, prostaglandins; STOP, surgical termination of pregnancy; TBS, Tris- buffered saline. ORIGINAL ARTICLE Endocrine Research doi: 10.1210/jc.2013-2922 J Clin Endocrinol Metab, March 2014, 99(3):871– 880 jcem.endojournals.org 871 Downloaded from https://academic.oup.com/jcem/article/99/3/871/2537293 by guest on 07 May 2021