Gastroesophageal reflux disease: Update on inflammation and symptom perception.

Although gastroesophageal reflux disease (GERD) is a common disorder in Western countries, with a significant impact on quality of life and healthcare costs, the mechanisms involved in the pathogenesis of symptoms remain to be fully elucidated. GERD symptoms and complications may result from a multifactorial mechanism, in which acid and acid-pepsin are the important noxious factors involved. Prolonged contact of the esophageal mucosa with the refluxed content, probably caused by a defective anti-reflux barrier and luminal clearance mechanisms, would appear to be responsible for macroscopically detectable injury to the esophageal squamous epithelium. Receptors on acid-sensitive nerve endings may play a role in nociception and esophageal sensitivity, as suggested in animal models of chronic acid exposure. Meanwhile, specific cytokine and chemokine profiles would appear to underlie the various esophageal phenotypes of GERD, explaining, in part, the genesis of esophagitis in a subset of patients. Despite these findings, which show a significant production of inflammatory mediators and neurotransmitters in the pathogenesis of GERD, the relationship between the hypersensitivity and esophageal inflammation is not clear. Moreover, the large majority of GERD patients (up to 70%) do not develop esophageal erosions, a variant of the condition called non-erosive reflux disease. This summary aims to explore the inflammatory pathway involved in GERD pathogenesis, to better understand the possible distinction between erosive and non-erosive reflux disease patients and to provide new therapeutic approaches.