Effects of cagA+ and cagA- strains of Helicobacter pylori on the human gastric mucus layer thickness.
BACKGROUND
Infection with cytotoxin-associated gene A (cagA) Helicobacter pylori is associated with severe gastric diseases, with contradictory views being expressed concerning the effect of H. pylori on the gastric mucus thickness. The aim of the present study was to differentiate between the effect of cagA+ and cagA- strains on gastric mucus thickness.


METHODS
Ninety-nine patients without peptic ulcers who were not on medication were randomly recruited from consecutive endoscopy clinics: six biopsies (five antral, one body) were obtained from each patient. Cryostat sections (18 microm) were cut and stained using the modified periodic acid-Schiff/Alcian blue technique. Mucus thickness was measured using computer-assisted light microscopy. The H. pylori status was assessed by histology, Campylobacter-like organism (CLO)test and culture, and cagA+ status determined by polymerase chain reaction (PCR).


RESULTS
There was no significant difference (P = 0.784) in mean mucus thickness between cagA+ (52.7 +/- 1.2 microm, n = 10), cagA- (46.6 +/- 1.1 microm, n = 18) or H. pylori-negative patients (51.3 +/- 1.1 microm, n = 30). In cagA- patients, mucus thickness was significantly reduced with increased H. pylori colonization density, Spearman (r(s)) = -0.805, P < 0.0001. In contrast, in cagA+ patients there was a weak positive, but not significant, association between mucus thickness and H. pylori colonization density, r(s) = 0.333, P = 0.381.


CONCLUSIONS
The human gastric mucus thickness is not affected by infection with cagA+ or cagA- strains of H. pylori compared with uninfected. Although a trend of increased mucus thickness with cagA+ infection was observed.
Al-Marhoon
Mohammed S
MS
School of Biomedical Sciences, University of Leeds, West Yorkshire, UK. almarhoon@hotmail.com
Nunn
Sheila
S
Soames
Roger W
RW
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000032:analysis* / Q000235:genetics; D001426:Bacterial Proteins / Q000032:analysis* / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis; D016099:Endoscopy, Gastrointestinal; D005260:Female; D005752:Gastric Mucins / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D005756:Gastritis / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D016481:Helicobacter Infections / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D016480:Helicobacter pylori / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D006801:Humans; D008297:Male; D008875:Middle Aged
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D005752:Gastric Mucins; C080866:cagA protein, Helicobacter pylori