Endogenous Cannabinoids in Crohn’s Disease

Abstract

Background: An increasing number of people around the world suffer from Crohn’s disease (CD), one of the inflammatory bowel diseases (IBDs). Recent evidence suggests that the endogenous cannabinoid system plays an important role in IBD. The main endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG), are ligands of the CB1 and CB2 receptors that are expressed on immune cells. These receptors as well as endocannabinoids are believed to mediate inflammatory activity and participate in the pathophysiology of CD. Objective: Very little is known about the secretion of endogenous cannabinoids throughout the course of CD. Therefore, the aim of this study was to determine and analyze the 2-AG and AEA concentrations in children who suffered from CD. Methods: We studied 34 adolescents with CD, mean age 13.5 years ± 2.0. Blood samples were collected three times in the active phase of the disease (during admission to hospital, before treatment), 2–4 weeks later, during the treatment and clinical improvement of the patients, and 3–6 months later, in the period of remission. The control group included 33 healthy teenagers of the same age who were examined once. In all patients, fasting blood samples were collected in the morning. 2AG and AEA concentrations in serum were measured using EIA kits (Abclonal, Woburn, MA, USA and ELK Biotechnology Co., Ltd. Wuhan, China, respectively). Results: The median 2-AG concentration in the study group was stable: acute phase 907.4 [379.3; 1300.5] pg/mL, during treatment 715.1 [416.7; 1302.5] pg/mL; remission 991.1 [381.1; 1652.5] pg/mL, and similar to the values observed in the control group 761.8 [504.3; 1497.0] pg/mL. No significant differences were found between the results obtained at all time points in the study group and compared to the control group (in all cases p > 0.44). In the case of AEA, in the study group before treatment, the median concentration was 2.63 [2.24; 2.79] ng/mL and similar to values obtained during treatment 2.56 [2.33; 3.06] ng/mL, and in remission, with 2.61 [2.46; 2.85] ng/mL. All these concentrations were lower compared to the values measured in the control group of 3.18 [2.57; 3.88] ng/mL (p = 0.023, p = 0.035, p = 0.056, respectively). Conclusions: While 2-AG levels remained stable throughout the disease course and were comparable to controls, AEA concentrations were consistently lower in CD patients. Therefore, therapeutic interventions aimed at increasing AEA-related signaling, such as administration of its analogues or fatty acid amide hydrolase inhibitors, may improve symptoms associated with Crohn’s disease in children.