Cyclooxygenase-2 and Inflammation Mediators Have a Crucial Role in Reflux-Related Esophageal Histological Changes and Barrett's Esophagus

Gastroesophageal reflux (GER) causes injury of the esophageal squamous epithelium, a condition called reflux esophagitis. The sequence reflux-esophagitis-intestinal metaplasia-dysplasia-invasive cancer is widely accepted as the main adenocarcinogenetic pathway in the esophagus; however, the mechanisms of this progression need to be better defined. We evaluated COX-2 expression and activity in biopsies from patients affected with GER, and these parameters have been correlated with the stage of the disease, ceramide expression, apoptotic process, and angiogenesis. The effects of celecoxib on bile acid- and EGF-induced mucosal proliferation, apoptosis and angiogenesis have been also investigated. Four groups of patients were distinguished: non esophagitis, non erosive esophagitis, erosive esophagitis, and Barrett's esophagus. COX-2 expression, basal PGE(2) levels, proliferative activity, VEGF expression and apoptosis were evaluated in esophageal biopsies. COX-2 expression, basal PGE(2) levels, proliferative activity, VEGF expression and apoptosis progressively increase from non esophagitis patients to patients with non erosive and erosive esophagitis, to those with BE. Incubation of the cells with DCA/EGF increases PGE(2) production, proliferative activity and VEGF production, effects prevented by celecoxib pretreatment. Ceramide expression increased from non esophagitis patients to patients with non erosive and erosive esophagitis, and decreased in BE; caspase-3 activity progressively decreased from non esophagitis to BE patients, suggesting an impairment of the apoptotic process with disease progression. These results stand for a close relationship between progression of initial steps of gastroesophageal reflux disease (GERD) and COX-2, proliferative activity and EGF/VEGF expression and could have implications in GERD treatment in order to prevent its neoplastic evolution.