The effect of Helicobacter pylori on the surface hydrophobicity and phospholipid composition of the gastric mucosa

Abstract

In 1983 our laboratory reported that the canine gastric mucosa has clear hydrophobic properties as determined by contact angle analysis, which is routinely employed in industry to determine surface wettability¹. This technique is schematically depicted in Figure 1, in which a microlitre droplet of water is applied to a test surface, and the contact angle at the air/liquid/solid interface is read through a telescopic eyepiece. A large contact angle reading is observed when the droplet beads up after it is applied to a hydrophobic surface, whereas minimal values are registered when the droplet is applied to, and attempts to coat, a wettable surface. Since this observation, reports from our laboratory and those of other investigators have indicated that the stomachs of all mammalian species tested to date, including humans, have non-wettable properties that appear to be attributable to the hydrophobic characteristics of the overlying mucus gel layer^1–7. Biochemical and biophysical analyses indicate that this unique surface property appears to be attributable to the presence of surface-active phospholipids present within and coating the mucus gel layer, with phosphatidylcholine being the most prominent constituent, representing 40–60% of the total^8–10. Ultrastructural studies employing special stains and fixatives to preserve and stain basic phospholipids indicate that surface-active phospholipids are synthesized and stored in specific organelles of gastric surface mucous cells, which are in turn secreted into the mucus gel layer upon stimulation^11–16.