Factors affecting gastric mucosal hydrophobicity in man.

Contact angle measurements in animal studies have demonstrated that gastric mucosa has a relatively hydrophobic surface. We have developed and validated a technique for the measurement of this property on human endoscopic biopsy specimens. Mean contact angle of the gastric body (70 degrees) and antrum (70 degrees) was higher than the duodenal bulb (62 degrees; p less than 0.01) and distal duodenum (50 degrees; p less than 0.001). Subjects with duodenal ulcer and gastric ulcer had a lower contact angle than controls without ulcer (57 degrees, n = 49, and 59 degrees, n = 17 versus 66 degrees, n = 124, respectively). Helicobacter pylori infection was associated with reduced contact angle in subjects with gastritis (59 degrees versus 68 degrees). The contact angle was unchanged after treatment with ranitidine but increased to control values after clearance and eradication of H. pylori with bismuth and antibiotics. In postgastrectomy patients, the contact angle was reduced and correlated negatively with the bile acid content of gastric juice (r = 0.51, p less than 0.0001). We conclude that in man gastric mucosal hydrophobicity can be validly measured on endoscopic biopsy specimens and that it is high in health and reduced in bile reflux and in peptic ulcer disease, largely as a result of H. pylori infection.