cagA+ Helicobacter pylori induces greater levels of prostaglandin E2 than cagA- strains.
cagA+ Helicobacter pylori (HP) infection is associated with an increased risk of distal gastric cancer. Previous studies investigating the effect of HP infection on prostaglandin E2 (PGE2) levels have not differentiated between cagA+ and cagA- strains and consequently have produced contradictory results. The aim was to investigate the effect of cagA+ strains on PGE2 and enhance the understanding of the mechanisms leading to gastric diseases. Hundred patients without peptic ulcers and not on medication were recruited (one later excluded) from endoscopy clinics: six biopsies were obtained from each patient. PGE2, colonization density and histology were determined. In addition, HP status was assessed by histology, CLOtest and culture with cagA+ being determined by PCR. Sixty-nine patients were HP- and 30 HP+ (10 cagA+, 18 cagA-, 2 undetermined). In age and sex-matched patients, PGE2 was significantly greater (P = 0.04) in HP+ (37.2 +/- 1.2 pg/mg per 20 min) than in HP- (22.6 +/- 1.2). In patients without atrophy, those infected with cagA+ had significantly higher (P = 0.03) PGE2 levels (53 +/- 1.1) than HP- patients (22.6 +/- 1.1) and greater levels (P = 0.29) than cagA- patients (35 +/- 1.3). In conclusion, the increased levels of PGE2 in the presence of cagA+ infection could be an important factor by which cagA+ strains enhance the gastric mucus layer protective functions leading to established colonization, gastritis and increased risk of gastric cancer. However, further evaluation with a large-scale multi-centre study is required to substantiate this hypothesis.
School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK. almarhoon@hotmail.com
Mohammed S
MS
Al-Marhoon
Sheila
S
Nunn
Roger W
RW
Soames
D000368:Aged; D000942:Antigens, Bacterial / Q000096:biosynthesis* / Q000235:genetics; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D015232:Dinoprostone / Q000096:biosynthesis*; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D016481:Helicobacter Infections / Q000378:metabolism* / Q000382:microbiology; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D006801:Humans; D008297:Male; D008875:Middle Aged
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C080866:cagA protein, Helicobacter pylori; D015232:Dinoprostone