Helicobacter pylori CagA-positive strains affect oxygen free radicals generation by gastric mucosa.
BACKGROUND
Helicobacter pylori plays a key role in production of reactive oxygen metabolites (ROMs). However, the importance of virulent CagA-positive H. pylori strains remains to be determined. The aim of this study was to assess ROMs production in gastric biopsies of patients infected by H. pylori. Results were correlated to CagA status and acute inflammatory infiltration.


METHODS
Patients undergoing gastroscopy were enrolled. H. pylori infection was assessed by histology and 13C urea breath test. CagA status was assessed through serology. ROMs were assayed in gastric biopsies by luminol-enhanced chemiluminescence (CLS). Gastric mucosal inflammation was histologically graded and neutrophils were individually counted. Macroscopical damage was scored according to a modified Lanza score.


RESULTS
40 out of 60 patients evaluated were H. pylori (HP) positive. Of the 40 infected patients, 24 were CagA-positive. CLS emission was significantly higher in HP-CagA-positive patients than in HP-CagA-negatives and uninfected. ROMs production showed a significant correlation to neutrophil infiltrate in all groups.


CONCLUSIONS
Gastric mucosa of patients infected by HP-CagA-positive strains is characterized by a higher generation of ROMs and by greater neutrophil counts than that observed in HP-CagA-negative subjects. Since ROMs production is associated with DNA oxidative damage, a long-term stimulation by these strains might be relevant in the pathogenesis of gastric malignancies. Assessment of CagA status might be useful to discriminate patients in which H. pylori eradication is advisable.
Danese
S
S
Dept. of Clinical Chemistry, Gemelli Hospital, Catholic University, Rome, Italy.
Cremonini
F
F
Armuzzi
A
A
Candelli
M
M
Papa
A
A
Ojetti
V
V
Pastorelli
A
A
Di Caro
S
S
Zannoni
G
G
De Sole
P
P
Gasbarrini
G
G
Gasbarrini
A
A
D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000032:analysis; D046508:Culture Techniques; D005260:Female; D005609:Free Radicals / Q000032:analysis; D005753:Gastric Mucosa / Q000378:metabolism*; D005756:Gastritis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000821:virology; D005773:Gastroscopy; D016481:Helicobacter Infections / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D016480:Helicobacter pylori / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D011336:Probability; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D005609:Free Radicals; D017382:Reactive Oxygen Species; C080866:cagA protein, Helicobacter pylori