Expression and cellular localization of COX-1 and -2 in Helicobacter pylori gastritis.
BACKGROUND
There are conflicting reports on the expression of cyclooxygenase in Helicobacter pylori infection.


OBJECTIVE
To evaluate the expression of COX-1 and COX-2 in H. pylori gastritis at messenger RNA (mRNA) and protein levels.


METHODS
Endoscopic gastric biopsies were obtained from patients with non-ulcer dyspepsia. The levels of COX-1 and COX-2 mRNA were compared between H. pylori-infected and uninfected specimens using reverse transcription-polymerase chain reaction. The immunohistochemical findings were correlated with the cellular localization of cyclooxygenase mRNA using in situ hybridization.


RESULTS
A total of 40 H. pylori-infected and 40 uninfected specimens were studied. mRNA of COX-2 but not COX-1 was elevated in H. pylori-infected mucosa. COX-1 was localized to the mononuclear inflammatory, endothelial and smooth muscle cells in the lamina propria. COX-2 was barely detectable in uninfected mucosa but was strongly expressed in the foveolar and glandular epithelia in H. pylori gastritis.


CONCLUSIONS
Cyclooxygenase-1 is expressed in the mononuclear inflammatory, endothelial and smooth muscle cells in the lamina propria irrespective of the H. pylori status. By contrast, H. pylori induces COX-2 expression in the foveolar and glandular epithelia.
Chan
F K
FK
Department of Medicine & Therapeutics, The Chinese University of Hong Kong, Hong Kong. fklchan@cuhk.edu.hk
To
K F
KF
Ng
Y P
YP
Lee
T L
TL
Cheng
A S
AS
Leung
W K
WK
Sung
J J
JJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D005756:Gastritis / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D015870:Gene Expression; D016481:Helicobacter Infections / Q000378:metabolism*; D016480:Helicobacter pylori; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis
D007527:Isoenzymes; D008565:Membrane Proteins; D012333:RNA, Messenger; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases