Human gastric mucosal hydrophobicity does not decrease with Helicobacter pylori infection or chronological age

Background and aims: Infection with cytotoxin-associated gene A (cagA) Helicobacter pylori is associated with severe gastric diseases. Previous studies in humans have reported a decreased gastric hydrophobicity with H pylori infection. The aim of the present study was to differentiate between the effect of cagA+ and cagA- strains on gastric mucus hydrophobicity. Methods: One hundred patients without peptic ulcers and not on medication were randomly recruited from endoscopy clinics; each patient had six biopsies. Contact angle measurements were performed using a goniometer assisted by computer software. H pylori status was assessed by histology, Campylobacter-like organism test and culture, and cagA+ status was determined by polymerase chain reaction. Results: In age- and sex-matched patients, there was no significant difference (P=0.27) in contact angle between H pylori-positive (61±2.8°) and H pylori-negative patients (65.5±3.0°). There was also no significant difference (P=0.36) in contact angle among H pylori-negative, cagA- and cagA+ patients (65.5±3.0°, 58.6±3.6° and 63.4±4.9°, respectively). However, a trend of increased mean contact angles in cagA+ compared with cagA- and H pylori-negative patients was observed in patients 50 years and younger (68.3±8.3°, 61.1±6.1° and 63.6±2.2°, respectively; P=0.70) and in patients without atrophy (71.1±8°, 59.6±4° and 66±2°, respectively; P=0.30). In addition, there was no significant correlation between contact angles and patient age (r=0.104, P=0.306). Conclusions: The present study shows that H pylori infection and the chronological age have no effect on the gastric mucus hydrophobicity, but it highlights a trend of increased mucus hydrophobicity with cagA+ infection that needs to be supported by future studies.