Potential role of the cannabinoid receptor CB in the pathogenesis of erosive and non-erosive gastro-oesophageal reflux disease

BACKGROUND: Cannabinoid (CB) receptors have been located in brain areas involved in the triggering of TLESRs as well as in the nodose ganglion from which vagal afferents emanate. The distribution of CB(1) receptors has been investigated in the human gastrointestinal mucosa, as expression of inflammatory process. AIM: To evaluate the CB(1) expression in oesophageal mucosa. METHODS: A total of 87 consecutive subjects were enrolled: 10 controls, 39 NERD and 38 erosive oesophagitis. Eight specimens were taken from macroscopically normal mucosa. Five were processed by haematoxylin-eosin, MIB1/CB(1) evaluation and three for the RNA and proteins extraction. RESULTS: The mean MIB1-LI value was 31% and 22% in NERD and ERD patients, respectively, compared to 68% in the healthy subjects. Mean CB(1)mRNA/GUSB mRNA value of the controls was 0.66, while in GERD patients, it was 0.28. In NERD and ERD, the mean values of CB(1)/GUSB were 0.38 and 0.17, respectively, with highly significant differences between the NERD vs. ERD groups. Semi-quantitative analysis of CB(1) expression, performed with WB, shows in NERD patients a higher CB(1) receptor expression than ERD patients. CONCLUSIONS: With this study, we showed for the first time the presence of CB(1) receptors in the human oesophageal epithelium.