Salivary immunoreactive endothelin in patients with upper gastrointestinal diseases

Endothelins have been implicated in gastric mucosal damage in a variety of animal models. Furthermore, clinical reports also show elevated gastric mucosal endothelin-1 levels in patients suffering from peptic ulcer diseases. We have demonstrated, first, the presence of immunoreactive endothelin (IR-ET) in human saliva. We also show that endothelins are rather stable in human saliva. The present study was undertaken to determine whether patients with endoscopically proven upper gastrointestinal diseases have a salivary excess of IR-ET, compared with patients with a normal esophagogastroduodenoscopy. Saliva was collected from fasting subjects prior to esophagogastroduodenoscopy. The levels of IR-ET were measured by the radioimmunoassay method. The salivary concentrations of IR-ET in the studied subjects were as follows: 8.9 +/- 1.0 fmol/mL (mean +/- standard error of the mean) for patients with gastric ulcers (n = 18); 7.3 +/- 1.0 fmol/mL for patients with duodenal ulcers (n = 22); and 6.8 +/- 0.6 fmol/mL for patients with gastritis (n = 28). These values are all higher than that of normal subjects (4.4 +/- 0.5 fmol/mL, n = 20; P < 0.001, P < 0.01, and P < 0.05, respectively). No significant differences in salivary IR-ET were noted between patients with a normal esophagogastroduodenoscopy and patients with esophagitis (3.8 +/- 0.7 fmol/mL, n = 4) or gastric cancer (5.3 +/- 1.4 fmol/mL, n = 4). There were no significant differences in the salivary IR-ET levels between males and females. However, the salivary IR-ET levels in the smokers (8.0 +/- 0.6 fmol/mL, n = 38) were significantly higher (P < 0.01) than those of the non-smokers (6.0 +/- 0.4 fmol/mL, n = 58). There was no correlation of IR-ET levels with age. Our findings suggest that salivary endothelin may have a contributing role in certain gastroduodenal diseases.