anandamide and Celiac-Disease

The endocannabinoid system has been extensively investigated in experimental colitis and inflammatory bowel disease, but not in celiac disease, where only a single study showed increased levels of the major endocannabinoid anandamide in the atrophic mucosa. On this basis, we aimed to investigate anandamide metabolism in celiac disease by analyzing transcript levels (through quantitative real-time reverse transcriptase-polymerase chain reaction), protein concentration (through immunoblotting) and activity (through radioassays) of enzymes responsible for anandamide synthesis (N-acylphosphatidyl-ethanolamine specific phospholipase D, NAPE-PLD) and degradation (fatty acid amide hydrolase, FAAH) in the duodenal mucosa of untreated celiac patients, celiac patients on a gluten-free diet for at least 12 months and control subjects. Also, treated celiac biopsies cultured ex vivo with peptic-tryptic digest of gliadin were investigated. Our in vivo experiments showed that mucosal NAPE-PLD expression and activity are higher in untreated celiac patients than treated celiac patients and controls, with no significant difference between the latter two groups. In keeping with the in vivo data, the ex vivo activity of NAPE-PLD was significantly enhanced by incubation of peptic-tryptic digest of gliadin with treated celiac biopsies. On the contrary, in vivo mucosal FAAH expression and activity did not change in the three groups of patients, and accordingly, mucosal FAAH activity was not influenced by treatment with peptic-tryptic digest of gliadin. In conclusion, our findings provide a possible pathophysiological explanation for the increased anandamide concentration previously shown in active celiac mucosa.

Topics: Adult; Amidohydrolases; Arachidonic Acids; Biopsy; Blotting, Western; Case-Control Studies; Celiac Disease; Diet, Gluten-Free; Duodenum; Endocannabinoids; Female; Gliadin; Humans; Intestinal Mucosa; Male; Middle Aged; Phospholipase D; Polyunsaturated Alkamides; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Up-Regulation; Young Adult

The endocannabinoid system is upregulated in both human inflammatory bowel diseases and experimental models of colitis. In this study, we investigated whether this upregulation is a marker also of celiac disease-induced atrophy. The levels of the cannabinoid CB(1) receptor, of the endocannabinoids, anandamide, and 2-arachidonoyl-glycerol (2-AG), and of the anti-inflammatory mediator palmitoylethanolamide (PEA) were analyzed in bioptic samples from the duodenal mucosa of celiac patients at first diagnosis assessed by the determination of antiendomysial antibodies and histological examination. Samples were analyzed during the active phase of atrophy and after remission and compared to control samples from non-celiac patients. The levels of anandamide and PEA were significantly elevated (approx. 2- and 1.8-fold, respectively) in active celiac patients and so were those of CB(1) receptors. Anandamide levels returned to normal after remission with a gluten-free diet. We also analyzed endocannabinoid and PEA levels in the jejunum of rats 2, 3, and 7 days after treatment with methotrexate, which causes inflammatory features (assessed by histopathological analyses and myeloperoxidase activity) similar to those of celiac patients. In both muscle/serosa and mucosa layers, the levels of anandamide, 2-AG, and PEA peaked 3 days after treatment and returned to basal levels at remission, 7 days after treatment. Thus, intestinal endocannabinoid levels peak with atrophy and regress with remission in both celiac patients and methotrexate-treated rats. The latter might be used as a model to study the role of the endocannabinoid system in celiac disease.

Topics: Adolescent; Adult; Amides; Animals; Arachidonic Acids; Atrophy; Cannabinoid Receptor Modulators; Case-Control Studies; Celiac Disease; Child; Diet, Protein-Restricted; Disease Models, Animal; Duodenum; Endocannabinoids; Ethanolamines; Female; Glycerides; Humans; Jejunum; Male; Methotrexate; Middle Aged; Palmitic Acids; Peroxidase; Polyunsaturated Alkamides; Rats; Rats, Wistar; Receptor, Cannabinoid, CB1; Time Factors; Up-Regulation