Saliva and esophageal protection

There has been much interest in recent years in the potential protective ro le of saliva in the esophagus. Variables such as salivary volume and neutra lizing capacity have been studied both during basal conditions and in respo nse to esophageal acid exposure, in healthy subjects and in patients with e sophagitis. in addition to its known neutralizing capacity, saliva also con tains growth factors. These polypeptides (of which epidermal growth factor has been studied most) have cytoprotective and healing properties in variou s segments of the gastrointestinal tract. Therefore, a deficiency in one or more of these growth factors might be a contributing factor in the develop ment of gastroesophageal reflux disease (GERD) or its complication, such as Barrett's metaplasia. However, human studies have produced contradictory r esults regarding salivary growth factor deficiency in such patients. Curren t methods of investigation make it difficult to assess the importance of sa liva in GERD. This may be due in part to the multifactorial nature of the d isease and the difficulty in long-term, selective manipulation of salivary function in humans. Given the present data in the literature, it is therefo re unknown if saliva plays an important role in esophageal protection. (Am J Gastroenterol 1999;94: 1446-1452. (C) 1999 by Am. Coll. of Gastroenterolo gy).